The amine-functionalized mesoporous silica materials were prepared via the co-condensation reaction of tetraethoxysilane and three types of organoalkoxysilanes： 3-aminopropyl-trimethoxysilane, n-（2-aminoethyl）-3-am...The amine-functionalized mesoporous silica materials were prepared via the co-condensation reaction of tetraethoxysilane and three types of organoalkoxysilanes： 3-aminopropyl-trimethoxysilane, n-（2-aminoethyl）-3-aminopropyltrimethoxysilane, and 3-（2-（2- aminoehtylamino）ethylamino） propyl-trimethoxysilane. Cetyltrimethylammonium bromide was used as a template for forming pores, Specific surface area and pore volume of the amine-functionalized mesoporous silica materials were determined using surface area and pore size analyzer. Fourier transform infrared （FTIR） spectroscope was employed for identifying the functional groups on pore surface. In addition, the amine-functionalized mesoporous silica materials were applied as adsorbents for adsorbing formaldehyde vapor. FTIR spectra showed the evidence of the reaction between formaldehyde molecules and amine groups on pore surface of adsorbents. The equilibrium data of formaldehyde adsorbed on the adsorbents were analyzed using the Langmuir, Freundlich and Temkin isotherm. The sample functionalized from n-（2-aminoethyl）-3-aminopropyltrimethoxysilane showed the highest adsorption capacity owing to its amine groups and the large pore diameter.展开更多
Recent trends in seasonal cycles in China are analyzed, based on a homogenized dataset of daily temperatures at 541 stations during the period 1960–2008. Several indices are defined for describing the key features of...Recent trends in seasonal cycles in China are analyzed, based on a homogenized dataset of daily temperatures at 541 stations during the period 1960–2008. Several indices are defined for describing the key features of a seasonal cycle, including local winter/summer （LW/LS） periods and local spring/autumn phase （LSP/LAP）. The Ensemble Empirical Mode Decomposition method is applied to determine the indices for each year. The LW period was found to have shortened by 2–6 d （10 yr）-1, mainly due to an earlier end to winter conditions, with the LW mean temperature having increased by 0.2°C–0.4°C （10 yr）？1, over almost all of China. Records of the most severe climate extremes changed less than more typical winter conditions did. The LS period was found to have lengthened by 2–4 d （10 yr）？1, due to progressively earlier onsets and delayed end dates of the locally defined hot period. The LS mean temperature increased by 0.1°C–0.2°C （10 yr）-1 in most of China, except for a region in southern China centered on the mid-lower reaches of the Yangtze River. In contrast to the winter cases, the warming trend in summer was more prominent in the most extreme records than in those of more typical summer conditions. The LSP was found to have advanced significantly by about 2 d （10 yr）-1 in most of China. Changes in the autumn phase were less prominent. Relatively rapid changes happened in the 1980s for most of the regional mean indices dealing with winter and in the 1990s for those dealing with summer.展开更多
Aqueous Zinc-ion batteries(ZIB) are attracting immense attention because of their merits of excellent safety and quite cheap properties compared with lithium-ion batteries(LIB).Manganese oxide is one of the most impor...Aqueous Zinc-ion batteries(ZIB) are attracting immense attention because of their merits of excellent safety and quite cheap properties compared with lithium-ion batteries(LIB).Manganese oxide is one of the most important cathode materials of ZIB.In this paper,α-Mn2O3 used as cathode of ZIB is synthesized via Metal-Organic Framework(MOF)-derived method,which delivers a high specific capacity of225 mAh g^(-1) at 0.05 A g^(-1) and 92.7 mAh g^(-1) after 1700 cycles at 2 A g^(-1).The charge storage mechanism of α-Mn2O3 cathode is found to greatly depend on the discharge current density.At lower current density discharging,the H+ and Zn2+ are successively intercalated into the α-Mn2O3 before and after the "turning point" of discharge voltage and their discharging products present obviously different morphologies changing from flower-like to large plate-like products.At a higher current density,the low-voltage plateau after the turning point disappears due to the decrease of amount of Zn2+ intercalation and the H+intercalation is dominated in α-Mn2 O3.This study provides significant understanding for future design and research of high-performance Mn-based cathodes of ZIB.展开更多
South China （SC） experienced persistent heavy rain in June 2010. The climatic anomalies and related mechanism are analyzed in this study. Results show that the large-scale circulation pattern favorable for precipita...South China （SC） experienced persistent heavy rain in June 2010. The climatic anomalies and related mechanism are analyzed in this study. Results show that the large-scale circulation pattern favorable for precipitation was maintained. In the upper level, the South Asian High and westerly jet stream provided a divergent circulation over SC. In the middle and low levels, an anomalous strong subtropical high （STH） extended to the South China Sea. The southwesterly monsoon flow along the northwest flank of the STH transported abundant water vapor from the western North Pacific, the Bay of Bengal, and the South China Sea to SC. The precipitation can be classified into two types： the West Siberia low （WSL）-induced low-level cyclone mode, and the STH-induced low-level jet mode. STH and WSL indices are defined to estimate the influence of these two systems, respectively. Analysis shows that both are critical for precipitation, but their respective contributions differ from year to year. In 2010, both were important factors for the heavy rainfall in June.展开更多
SnO_(2)/graphene nanocomposites have been fabricated by a simple chemical method.In the fabrication process,the control of surface charge causes echinoid-like SnO_(2)nanoparticles to be formed and uniformly decorated ...SnO_(2)/graphene nanocomposites have been fabricated by a simple chemical method.In the fabrication process,the control of surface charge causes echinoid-like SnO_(2)nanoparticles to be formed and uniformly decorated on the graphene.The electrostatic attraction between a graphene nanosheet(GNS)and the echinoid-like SnO_(2)particles under controlled pH creates a unique nanostructure in which extremely small SnO_(2)particles are uniformly dispersed on the GNS.The SnO_(2)/graphene nanocomposite has been shown to perform as a high capacity anode with good cycling behavior in lithium rechargeable batteries.The anode retained a reversible capacity of 634 mA·h·g^(–1)with a coulombic efficiency of 98%after 50 cycles.The high reversibility can be attributed to the mechanical buffering by the GNS against the large volume change of SnO_(2)during delithiation/lithiation reactions.Furthermore,the power capability is significantly enhanced due to the nanostructure,which enables facile electron transport through the GNS and fast delithiation/lithiation reactions within the echinoid-like nano-SnO_(2).The route suggested here for the fabrication of SnO_(2)/graphene hybrid materials is a simple economical route for the preparation of other graphene-based hybrid materials which can be employed in many different fields.展开更多
Compared to organic-inorganic hybrid perovskites,the cesium-based allinorganic lead halide perovskite(CsPbI_(3))is a promising light absorber for perovskite solar cells owing to its higher resistance to thermal stress...Compared to organic-inorganic hybrid perovskites,the cesium-based allinorganic lead halide perovskite(CsPbI_(3))is a promising light absorber for perovskite solar cells owing to its higher resistance to thermal stress.Nonetheless,additional research is required to reduce the nonradiative recombination to realize the full potential of CsPbI_(3).Here,the diffusion of Cs ions participating in ion exchange is proposed to be an important factor responsible for the bulk defects inγ-CsPbI_(3)perovskite.Calculations based on first-principles density functional theory reveal that the[PbI_(6)]^(4-)octahedral tilt modifies the perovskite crystallographic properties inγ-CsPbI_(3),leading to alterations in its bandgap and crystal strain.In addition,by substituting amorphous barium titanium oxide(a-BaTiO_(3))for TiO_(2)as the electron transport layer,interfacial defects caused by imperfect energy levels between the electron transport layer and perovskite are reduced.High-resolution transmission electron microscopy and electron energy loss spectroscopy demonstrate that a-BaTiO_(3)forms entirely as a single phase,as opposed to Ba-doped TiO_(2)hybrid nanoclusters or separate domains of TiO_(2)and BaTiO_(3)phases.Accordingly,inorganic perovskite solar cells based on the a-BaTiO_(3)electron transport layer achieved a power conversion efficiency of 19.96%.展开更多
The fruit of Morinda citrifolia L., commonly known as noni, has an extensive history of use as a food and traditional medicine around the world. Adding value to Morinda citrifolia L. products, particularly the fruit, ...The fruit of Morinda citrifolia L., commonly known as noni, has an extensive history of use as a food and traditional medicine around the world. Adding value to Morinda citrifolia L. products, particularly the fruit, could be one way of building resilience in vulnerable farming households. The aim of this study was to determine the secondary metabolite and mineral composition of noni juice obtained by fermenting the fruit of Morinda citrifolia L. Fruits were collected in August 2022 from the local field in Thiès region, West of Senegal. Extraction yields were determined and the secondary metabolites were determined using conventional analytical methods. Calcium, magnesium, iron, sodium and potassium were determined by atomic absorption spectrophotometer coupled with a CCD detector. The results show that an average fruit mass (503.2 ± 110.96 g) consists of 171.44 ± 50.01 g pulp and 34.06 ± 10.35 g seeds. The traditional extraction yield of noni juice is 16.46% after three weeks of fermentation. The contents of total polyphenols, flavonoids and tannins obtained in noni are 608.97 ± 4.53 mg EAG/100mL, 7.78 ± 0.01 mg EQ/100mL and 0.191 ± 0.01 mg EC/100mL respectively. The ethanol content of noni varies from 3.57 to 5.23 mL/100mL during extraction. Noni has a high calcium content with a concentration of 383.79 ± 33.23 mg/L. This is followed by a good concentration of magnesium, potassium and sodium, at 278.47 ± 26.30, 187.43 ± 10.7 and 155.95 ± 28.66 mg/L respectively. Noni also has an iron content of 202.15 ± 0.05 mg/L.展开更多
Our previous study showed that the frictional drag decreases with increasing void fraction at Re〉1300, while it increases at Re 〈 1000. Decomposition of the Reynolds shear stress also implied that bubbles induce iso...Our previous study showed that the frictional drag decreases with increasing void fraction at Re〉1300, while it increases at Re 〈 1000. Decomposition of the Reynolds shear stress also implied that bubbles induce isotropy of turbulence. In order to confirm our previous analysis and to further investigate flow fields in the vicinity of bubbles, we analyze velocity fluctuations on the quadrant space in the streamwise and transverse directions （u′-v′ plane）. Here, we focus on two specific Reynolds numbers （at Re≈900 and ≈1410, which are close to the laminar-to-turbulent transition regime） and discuss bubble effects on sweep （u′〉 0, v′〈 0 ） and ejection （u′〈 0, v′〉 0） events as a function of the Reynolds number. We also illustrate velocity fluctuations in the vicinity of an individual bubble and a swarm of bubbles on the u′- v′ coordinates. The results show that a bubble swarm suppresses the velocity fluctuations at Re≈1410.展开更多
A novel polybenzimidazole(PBI)-based trilayer membrane assembly is developed for application in vanadium redox flow battery(VRFB).The membrane comprises a 1μm thin cross-linked poly[2,2′-(p-oxydiphenylene)−5,5′-bib...A novel polybenzimidazole(PBI)-based trilayer membrane assembly is developed for application in vanadium redox flow battery(VRFB).The membrane comprises a 1μm thin cross-linked poly[2,2′-(p-oxydiphenylene)−5,5′-bibenzimidazole](OPBI)sandwiched between two 20μm thick porous OPBI membranes(p-OPBI)without further lamination steps.The trilayer membrane demonstrates exceptional properties,such as high conductivity and low area-specific resistance(ASR)of 51 mS cm−1 and 81mΩcm^(2),respectively.Contact with vanadium electrolyte increases the ASR of trilayer membrane only to 158mΩcm^(2),while that of Nafion is 193mΩcm^(2).VO^(2+)permeability is 2.73×10^(-9) cm^(2) min^(−1),about 150 times lower than that of Nafion NR212.In addition,the membrane has high mechanical strength and high chemical stability against VO^(2+).In VRFB,the combination of low resistance and low vanadium permeability results in excellent performance,revealing high Coulombic efficiency(>99%),high energy efficiency(EE;90.8%at current density of 80mA cm^(−2)),and long-term durability.The EE is one of the best reported to date.展开更多
Developi ng alter native oxyge n reducti on reactio n (ORR) catalysts to replace precious Pt-based metals with abundant materials is the key challe nge of commercial application of fuel cells. Owing to their various c...Developi ng alter native oxyge n reducti on reactio n (ORR) catalysts to replace precious Pt-based metals with abundant materials is the key challe nge of commercial application of fuel cells. Owing to their various compositi ons and tun able electronic properties, transition metal dichalcogenides (TMDs) have the great potential to realize high-efficiency catalysts for ORR. Here, various 3R-phase dichalcogenides of group VB and VIB transition metals (MX2, M = Nb, Ta, Mo, W;X = S, Se, Te) are investigated for ORR catalysts by using density functional theory calculations. The computed over-potentials of group VB TMDs are much less than those of group VIB TMDs. For group VB TMDs, a volcano-type plot of ORR catalytic activity is established on the adsorption energies of *OH, and NbS2 and TaTe2 exhibit best ORR activity with an oveepotential of 0.54 V. To achieve even better activity, strain engineering is performed to tune ORR catalytic activity, and the minimum over-potential of 0.43 V can be realized. We further dem on strate that the shift of p orbital center of surface chalcoge n elements under strain is responsible for tuning the catalytic activity of TMDs.展开更多
The purpose of this study is to investigate the physicochemical properties of some local varieties of onion (Allium cepa L.) and compare them with an imported variety, all collected in May 2021. Proteins, reducing sug...The purpose of this study is to investigate the physicochemical properties of some local varieties of onion (Allium cepa L.) and compare them with an imported variety, all collected in May 2021. Proteins, reducing sugars, lipids, and polyphenol content were estimated according to the AFNOR standardized methods. The determination of calcium, magnesium, iron, sodium, potassium and phosphorus was performed by atomic absorption spectrophotometer coupled with a CCD detector. The results highlighted an average acidity of 0.377% ± 0.002% lower than the value of the imported variety which is 0.520% ± 0.001%. Local varieties have a pH ranging from 6.35 ± 0.003 to 6.42 ± 0.004, while the variety has a pH of 6.36 ± 0.003. The ash and dry matter contents vary respectively from 4.788% ± 0.004% to 8.253% ± 0.003% and 7.945% ± 0.021% to 11.945% ± 0.007% for the local varieties. Moreover, the imported one has ash and dry matter contents of 5.175% ± 0.007% and 10.035% ± 0.021% respectively. The results show that the protein, reducing sugar and lipid contents in the local onion varieties vary respectively from 2.815 ± 0.000 to 15.634 ± 0.001 g·100 g<sup>-1</sup>;4.691 ± 0.001 to 12.596 ± 0.002 g·100 g<sup>-1</sup> and 0.006 ± 0.001 to 0.050 ± 0.057 g·100 g<sup>-1</sup>. Furthermore, the imported variety has a protein, reducing sugar and lipid content of 5.649 ± 0.002;8.565 ± 0.002 g·100 g<sup>-1</sup> and 0.011 ± 0.010 g·100 g<sup>-1</sup> respectively. The maximum levels of total polyphenols are obtained in the imported variety, Bellani and Gandiol, respectively 9.973 ± 0.001, 4.535 ± 0.002, and 3.425 ± 0.006 mg EAG/g of dry matter. The local varieties have a significant calorific intake of between 35.451 ± 0.001 and 112.980 ± 0.003 kcal·100 g<sup>-1</sup> compared to the imported one with an energy value of 56.953 ± 0.001 kcal·100 g<sup>-1</sup> of dry matter. The bulbs of different onion varieties studied have a fairly high content of mineral elements. The potassium content of local varieties is展开更多
Mixed-dimensional composite structures using zero-dimensional(0D)quantum dots(QDs)and two-dimensional(2D)transition metal dichalcogenides(TMDs)materials are expected to attract great interest in optoelectronics due to...Mixed-dimensional composite structures using zero-dimensional(0D)quantum dots(QDs)and two-dimensional(2D)transition metal dichalcogenides(TMDs)materials are expected to attract great interest in optoelectronics due to the potential to generate new optical properties.Here,we report on the unique optical characteristics of a devices with mixed dimensional vertically stacked structures based on tungsten diselenide(WSe_(2))/CdSeS QDs monolayer/molybdenum disulfide(MoS_(2))(2D/0D/2D).Specifically,it exhibits an ambipolar photoresponse characteristic,with a negative photoresponse observed in the 400-600 nm wavelength range and a positive photoresponse appeared at 700 nm wavelength.It resulted in the high negative responsivity of up to 52.22 mA·W^(−1)under 400 nm,which is 163 times higher than that of the photodetector without CdSeS QDs.We also demonstrated the negative photoresponse,which could be due to increased carrier collision probability and non-radiative recombination.Device modeling and simulation reveal that Auger recombination among the types of non-radiative recombination is the main cause of negative photocurrent generation.Consequently,we discovered ambipolar photoresponse near a specific wavelength corresponding to the energy of quantum dots.Our study revealed interesting phenomenon in the mixed low-dimensional stacked structure and paved the way to exploit it for the development of innovative photodetection materials as well as for optoelectronic applications.展开更多
Core-shell-type bimetallic oxide and carbon composites comprising zinc oxide(ZnO)nanospheres and zinc manganese oxide(ZnMn_(2)O_(4))nanowires were produced by a hydrothermal method,and supersoni-cally sprayed together...Core-shell-type bimetallic oxide and carbon composites comprising zinc oxide(ZnO)nanospheres and zinc manganese oxide(ZnMn_(2)O_(4))nanowires were produced by a hydrothermal method,and supersoni-cally sprayed together with reduced graphene oxide(rGO)nanosheets onto Ni foil to fabricate flexible su-percapacitors.The supersonic impact facilitated the exfoliation of the rGO nanosheets,thereby increasing the surface area and adhesion of the composite particles to the substrate.The rGO nanosheets were vertically aligned during the supersonic impact and formed localized zones,enabling optimal accommodation of the ZnO/ZnMn_(2)O_(4)particles.This localization,with the addition of rGO,reduced the agglomeration of ZnO/ZnMn_(2)O_(4)particles.The molar concentration of MnSO_(4)used in the synthesis of ZnO/ZnMn_(2)O_(4)was varied from 0.05 to 0.15 mol/L to determine the optimal MnSO_(4)concentration that would result in the highest energy storage capacitance.The unique nanostructure of ZnO/ZnMn_(2)O_(4)and the self-alignment of rGO sheets facilitated a favorable environment for high energy storage capability with a specific capaci-tance of 276.3 mF·cm^(−2)at a current density of 0.5 mA·cm^(−2)and an energy density of 98.2μWh·cm^(−2)at a power density of 1600μW·cm^(−2).The width of the potential window was increased to 1.2 V,imply-ing a significant increase in the energy storage capability of the supercapacitor.Capacitance retention of 88%was achieved after 10,000 charge/discharge cycles for the supercapacitor fabricated using an optimal MnSO_(4)concentration(0.10 mol/L)during the composite synthesis.展开更多
For anode-free lithium metal battery,lithiophilic surface modification on the current collector can effectively reduce the lithium nucleation barrier,so as to regulate the electrodeposition of lithium.Here,atomically ...For anode-free lithium metal battery,lithiophilic surface modification on the current collector can effectively reduce the lithium nucleation barrier,so as to regulate the electrodeposition of lithium.Here,atomically dispersed Zn-(C/N/O)lithiophilic sites in the amorphous carbon medium were introduced onto Cu by an in-situ induced ion coordination chemistry strategy to get the modified Zn@NC@RGO@Cu current collector.X-ray absorption spectroscopy(XAS)combined with scanning transmission electron microscopy in high angle annular dark field(STEM-HAADF)analysis proved the single atomic state of the zinc sites surrounded by C,N,and O with a coordination number of~3.According to the electrochemical tests and first principle calculations,the ultra-uniformly dispersed Zn-(C/N/O)sites at the atomic level can effectively improve the lithium affinity,reduce the energy barrier for lithium nucleation,homogenize the lithium nucleation,and enhance an inorganic lithium compounds rich solid electrolyte interphase layer.As a result,the nucleation overpotential of lithium on the modified current collector was reduced to 7.7 mV,which was 5.4 times lower than that on bare Cu.Uniform lithium nucleation and deposition enabled stable Li plating/stripping and elevated Coulombic efficiency of 98.95%in Li||Cu cell after>850 cycles.Capacity retention of 89.7%was successfully achieved in the anode-free lithium metal battery after 100 cycles.展开更多
Since trees and plants can absorb CO2, forests are widely regarded as a carbon sink that may control the amount of CO2 in the atmosphere. The CO2 uptake rate of plants is affected by the plant species and environmenta...Since trees and plants can absorb CO2, forests are widely regarded as a carbon sink that may control the amount of CO2 in the atmosphere. The CO2 uptake rate of plants is affected by the plant species and environmental conditions such as photosynthetically active radiation (PAR), temperature, water and nutrient contents. PAR is the most immediate environmental control on photosynthesis while air temperature affects both photorespiration and dark respiration. In the natural condition, PAR and temperature play an important role in net CO2 uptake. The effects of PAR and air temperature on the CO2 uptake of Pterocarpus macrocarpus grown in a natural habitat were studied in the present work. Due to many uncontrollable factors, a simple rectangular hyperbola could not represent the measured data. The data were divided into groups of 2oC intervals; CO2 uptake in each group may then be related to PAR by a rectangular hyperbola function. Using the obtained functions, the effect of PAR was removed from the original data. The PAR-independent CO2 uptake was then related to air temperature. Finally, the effects of PAR (I) and air temperature (Ta) on the CO2 uptake rate (A) were combined as: (-0.0575Ta2+2.6691Ta-23.264)I A= ——————————————— (-0.00766Ta2+0.40666Ta-3.99924) (-4.8794Ta2+227.13Ta-2456.9)+I展开更多
Introducing Ni in Ru oxide is a promising approach to enhance the catalytic activity for the oxygen evolution reaction(OER).However,the role of Ni(which has a poor intrinsic activity)is not fully understood.Here,a Ru ...Introducing Ni in Ru oxide is a promising approach to enhance the catalytic activity for the oxygen evolution reaction(OER).However,the role of Ni(which has a poor intrinsic activity)is not fully understood.Here,a Ru NiO_(x)electrode fabricated via a modified dip coating method exhibited excellent OER performance in acidic media,and neutral media for CO_(2)reduction reaction.We combined in-situ/operando X-ray absorption near-edge structure and on-line inductively coupled plasma mass spectrometry studies to unveil the role of the Ni introduced in the Ru oxide.We propose that the Ni not only transforms the electronic structure of the Ru oxide,but also produces a large number of oxygen vacancies by distorting the oxygen lattice structure at low overpotentials,increasing the participation of lattice oxygen for OER.This work demonstrates the real behavior of bimetallic oxide materials under applied potentials and provides new insights into the development of efficient electrocatalysts.展开更多
Combining metal to form metal phosphide is a promising strategy to address the fast capacity decay of P rooted from its low electronic conductivity and large volume changes upon cycling. Cu_(3)P, which possesses a hig...Combining metal to form metal phosphide is a promising strategy to address the fast capacity decay of P rooted from its low electronic conductivity and large volume changes upon cycling. Cu_(3)P, which possesses a high theoretical gravimetric and volumetric capacity of 363 m Ahág^(-1) and 1028 AháL^(-1) and reasonable volume expansion of 156% during sodiation, was investigated as anode material in SIBs. Hollow-structured Cu_(3)P electrode delivers an initial de-sodiation capacity of * 159.0 m Ahág^(-1) with high capacity retention of ~85.1% over 50 cycles at 0.2 C rate and exhibits good rate performance,retaining 70% of the capacity when the current density increases from 0.2 C to 1.6 C. A 3 V-class full cell consisting of P2-Na_(2/3) Ni_(1/3) Mn_(1/2) Ti_(1/6)O_(2) cathode and Cu_(3)P anode was also assembled, which could achieve an energy density of ~189.3 Whákg^(-1)(based on the mass of both electrode materials) and average discharge voltage of~2.91 V when cycled in 1.0-4.3 V at 0.1C.展开更多
Tandem solar cells are a key technology for exceeding the theoretical efficiency limit of single-junction cells.One of the most promising combinations is the silicon–perovskite tandem cells,considering their potentia...Tandem solar cells are a key technology for exceeding the theoretical efficiency limit of single-junction cells.One of the most promising combinations is the silicon–perovskite tandem cells,considering their potential for high efficiency,fabrication on a large scale,and low cost.While most research focuses on improving each subcell,another key challenge lies in the tunnel junction that connects these subcells,significantly impacting the overall cell characteristics.Here,we demonstrate the first use of tunnel junctions using a stack of p+/n+polysilicon passivating contacts deposited directly on the tunnel oxide to overcome the drawbacks of conventional metal oxide-based tunnel junctions,including low tunneling efficiency and sputter damage.Using Random Forest analysis,we achieved high implied open circuit voltages over 700 mV and low contact resistivities of 500 mΩcm 2,suggesting fill factor losses of less than 1%abs for the operating conditions of a tandem cell.展开更多
Ozone(O3)is widely used in drinking water disinfection and wastewater treatment.However,when applied to bromide-containing water,ozone induces the formation of bromate,which is carcinogenic.Our previous study found...Ozone(O3)is widely used in drinking water disinfection and wastewater treatment.However,when applied to bromide-containing water,ozone induces the formation of bromate,which is carcinogenic.Our previous study found±at graphene oxide(GO)can enhance the degradation efficiency of micropollutants during ozonation.However,in this study,GO was found to promote bromate formation during ozonation of bromide-containing waters,with bromate yields from the O3/GO process more than twice those obtained using ozone alone.The promoted bromate formation was attributed to increased hydroxyl radical production,as confirmed by the significant reduction(almost 75%)in bromate yield after adding t-butanol(TBA).Cerium oxide(less tfian 5 mg/L)supported on reduced GO(xCeO2/RGO)significantly inhibited bromate formation during ozonation compared with reduced GO alone,and the optimal Ce atomic percentage(x)was determined to be 0.36%,achieving an inhibition rate of approximately 73%.Fourier transform infrared(FT-IR)spectra indicated the transformation of GO into RGO after hydrothermal treatment,and transmission electron microscope(TEM)results showed that CeO2 nanoparticles were well dispersed on the RGO surface.The X-ray photoelectron spectroscopy(XPS)spectra results demonstrated that the Ce^3+/Ce^4+ratio in xCeO2/RGO was almost 3-4 times higher than that in pure CeO2,which might be attributed to the charge transfer effect from GO to CeO2.Furthermore,Ce+on thexCeO2/RGO surface could quench Br-and BrO-to further inhibit bromate formation.Meanwhile,0.36CeO2/RGO could also enhance the degradation efficiency of N,N-diethyl-zn-toluamide(DEET)in synthetic and reclaimed water during ozonation.展开更多
Electron transport layer(ETL)is pivotal to charge carrier transport for PSCs to reach the Shockley-Queisser limit.This study provides a fundamental understanding of heterojunction electron transport layers(ETLs)at the...Electron transport layer(ETL)is pivotal to charge carrier transport for PSCs to reach the Shockley-Queisser limit.This study provides a fundamental understanding of heterojunction electron transport layers(ETLs)at the atomic level for stable and efficient perovskite solar cells(PSCs).The bilayer structure of an ETL composed of SnO_(2) on TiO_(2) was examined,revealing a critical factor limiting its potential to obtain efficient performance.Alteration of oxygen vacancies in the TiO_(2) underlayer via an annealing process is found to induce manipulated band offsets at the interface between the TiO_(2) and SnO_(2) layers.In-depth electronic investigations of the bilayer structure elucidate the importance of the electronic properties at the interface between the TiO_(2) and SnO_(2) layers.The apparent correlation in hysteresis phenomena,including current density-voltage(J-V)curves,appears as a function of the type of band alignment.Density functional theory calculations reveal the intimate relationship between oxygen vacancies,deep trap states,and charge transport efficiency at the interface between the TiO_(2) and SnO_(2) layers.The formation of cascade band alignment via control over the TiO_(2) underlayer enhances device performance and suppresses hysteresis.Optimal performance exhibits a power conversion efficiency(PCE)of 23.45%with an open-circuit voltage(V_(oc))of 1.184 V,showing better device stability under maximum power point tracking compared with a staggered bilayer under one-sun continuous illumination.展开更多
文摘The amine-functionalized mesoporous silica materials were prepared via the co-condensation reaction of tetraethoxysilane and three types of organoalkoxysilanes： 3-aminopropyl-trimethoxysilane, n-（2-aminoethyl）-3-aminopropyltrimethoxysilane, and 3-（2-（2- aminoehtylamino）ethylamino） propyl-trimethoxysilane. Cetyltrimethylammonium bromide was used as a template for forming pores, Specific surface area and pore volume of the amine-functionalized mesoporous silica materials were determined using surface area and pore size analyzer. Fourier transform infrared （FTIR） spectroscope was employed for identifying the functional groups on pore surface. In addition, the amine-functionalized mesoporous silica materials were applied as adsorbents for adsorbing formaldehyde vapor. FTIR spectra showed the evidence of the reaction between formaldehyde molecules and amine groups on pore surface of adsorbents. The equilibrium data of formaldehyde adsorbed on the adsorbents were analyzed using the Langmuir, Freundlich and Temkin isotherm. The sample functionalized from n-（2-aminoethyl）-3-aminopropyltrimethoxysilane showed the highest adsorption capacity owing to its amine groups and the large pore diameter.
基金supported bythe National Basic Research Program of China (Grant No.2009CB421401)Qian was supported by the National Natural Science Foundation of China (Grant No. 41005039)The work of Xia and Zhou was partly supported by astrategic research grant from the City University of HongKong (Grant No. SRG-Fd 7002505)
文摘Recent trends in seasonal cycles in China are analyzed, based on a homogenized dataset of daily temperatures at 541 stations during the period 1960–2008. Several indices are defined for describing the key features of a seasonal cycle, including local winter/summer （LW/LS） periods and local spring/autumn phase （LSP/LAP）. The Ensemble Empirical Mode Decomposition method is applied to determine the indices for each year. The LW period was found to have shortened by 2–6 d （10 yr）-1, mainly due to an earlier end to winter conditions, with the LW mean temperature having increased by 0.2°C–0.4°C （10 yr）？1, over almost all of China. Records of the most severe climate extremes changed less than more typical winter conditions did. The LS period was found to have lengthened by 2–4 d （10 yr）？1, due to progressively earlier onsets and delayed end dates of the locally defined hot period. The LS mean temperature increased by 0.1°C–0.2°C （10 yr）-1 in most of China, except for a region in southern China centered on the mid-lower reaches of the Yangtze River. In contrast to the winter cases, the warming trend in summer was more prominent in the most extreme records than in those of more typical summer conditions. The LSP was found to have advanced significantly by about 2 d （10 yr）-1 in most of China. Changes in the autumn phase were less prominent. Relatively rapid changes happened in the 1980s for most of the regional mean indices dealing with winter and in the 1990s for those dealing with summer.
基金supported by the National Natural Science Foundation of China (51672156)Local Innovative Research Teams Project of Guangdong Pearl River Talents Program (No. 2017BT01N111)+2 种基金Guangdong Province Technical Plan Project (2017B010119001)Shenzhen Technical Plan Project (JCYJ20170817161221958 and JCYJ20170412170706047)Shenzhen Graphene Manufacturing Innovation Center (201901161513)。
文摘Aqueous Zinc-ion batteries(ZIB) are attracting immense attention because of their merits of excellent safety and quite cheap properties compared with lithium-ion batteries(LIB).Manganese oxide is one of the most important cathode materials of ZIB.In this paper,α-Mn2O3 used as cathode of ZIB is synthesized via Metal-Organic Framework(MOF)-derived method,which delivers a high specific capacity of225 mAh g^(-1) at 0.05 A g^(-1) and 92.7 mAh g^(-1) after 1700 cycles at 2 A g^(-1).The charge storage mechanism of α-Mn2O3 cathode is found to greatly depend on the discharge current density.At lower current density discharging,the H+ and Zn2+ are successively intercalated into the α-Mn2O3 before and after the "turning point" of discharge voltage and their discharging products present obviously different morphologies changing from flower-like to large plate-like products.At a higher current density,the low-voltage plateau after the turning point disappears due to the decrease of amount of Zn2+ intercalation and the H+intercalation is dominated in α-Mn2 O3.This study provides significant understanding for future design and research of high-performance Mn-based cathodes of ZIB.
基金supported by the National Basic Research Program of China(Grant No.2009CB421405)the National Natural Science Foundation of China(Grant Nos.41025017and40921160379)partly supported by City University of Hong Kong(GrantNo.7002717)
文摘South China （SC） experienced persistent heavy rain in June 2010. The climatic anomalies and related mechanism are analyzed in this study. Results show that the large-scale circulation pattern favorable for precipitation was maintained. In the upper level, the South Asian High and westerly jet stream provided a divergent circulation over SC. In the middle and low levels, an anomalous strong subtropical high （STH） extended to the South China Sea. The southwesterly monsoon flow along the northwest flank of the STH transported abundant water vapor from the western North Pacific, the Bay of Bengal, and the South China Sea to SC. The precipitation can be classified into two types： the West Siberia low （WSL）-induced low-level cyclone mode, and the STH-induced low-level jet mode. STH and WSL indices are defined to estimate the influence of these two systems, respectively. Analysis shows that both are critical for precipitation, but their respective contributions differ from year to year. In 2010, both were important factors for the heavy rainfall in June.
基金This work was supported by a grant from the Korea Science and Engineering Foundation(KOSEF)(WCU program,No.31-2008-000-10055-0)a grant from the National Research Foundation of Korea(No.NRF-2009-0094219)funded by the Ministry of Education and Science and Technology(MEST)the Energy Resources Technology R&D program(No.20092020100040)under the Ministry of Knowledge Economy.
文摘SnO_(2)/graphene nanocomposites have been fabricated by a simple chemical method.In the fabrication process,the control of surface charge causes echinoid-like SnO_(2)nanoparticles to be formed and uniformly decorated on the graphene.The electrostatic attraction between a graphene nanosheet(GNS)and the echinoid-like SnO_(2)particles under controlled pH creates a unique nanostructure in which extremely small SnO_(2)particles are uniformly dispersed on the GNS.The SnO_(2)/graphene nanocomposite has been shown to perform as a high capacity anode with good cycling behavior in lithium rechargeable batteries.The anode retained a reversible capacity of 634 mA·h·g^(–1)with a coulombic efficiency of 98%after 50 cycles.The high reversibility can be attributed to the mechanical buffering by the GNS against the large volume change of SnO_(2)during delithiation/lithiation reactions.Furthermore,the power capability is significantly enhanced due to the nanostructure,which enables facile electron transport through the GNS and fast delithiation/lithiation reactions within the echinoid-like nano-SnO_(2).The route suggested here for the fabrication of SnO_(2)/graphene hybrid materials is a simple economical route for the preparation of other graphene-based hybrid materials which can be employed in many different fields.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)granted financial resource from the Ministry of Trade,Industry&Energy,Republic of Korea(20213091010020)the Korea Institute of Planning and Evaluation for Technology in Food,Agriculture and Forestry(IPET)and Korea Smart Farm R&D Foundation(KosFarm)through Smart Farm Innovation Technology Development Programfunded by Ministry of Agriculture,Food and Rural Affairs(MAFRA),Ministry of Science and ICT(MSIT),Rural Development Administration(RDA)(421036-03)
文摘Compared to organic-inorganic hybrid perovskites,the cesium-based allinorganic lead halide perovskite(CsPbI_(3))is a promising light absorber for perovskite solar cells owing to its higher resistance to thermal stress.Nonetheless,additional research is required to reduce the nonradiative recombination to realize the full potential of CsPbI_(3).Here,the diffusion of Cs ions participating in ion exchange is proposed to be an important factor responsible for the bulk defects inγ-CsPbI_(3)perovskite.Calculations based on first-principles density functional theory reveal that the[PbI_(6)]^(4-)octahedral tilt modifies the perovskite crystallographic properties inγ-CsPbI_(3),leading to alterations in its bandgap and crystal strain.In addition,by substituting amorphous barium titanium oxide(a-BaTiO_(3))for TiO_(2)as the electron transport layer,interfacial defects caused by imperfect energy levels between the electron transport layer and perovskite are reduced.High-resolution transmission electron microscopy and electron energy loss spectroscopy demonstrate that a-BaTiO_(3)forms entirely as a single phase,as opposed to Ba-doped TiO_(2)hybrid nanoclusters or separate domains of TiO_(2)and BaTiO_(3)phases.Accordingly,inorganic perovskite solar cells based on the a-BaTiO_(3)electron transport layer achieved a power conversion efficiency of 19.96%.
文摘The fruit of Morinda citrifolia L., commonly known as noni, has an extensive history of use as a food and traditional medicine around the world. Adding value to Morinda citrifolia L. products, particularly the fruit, could be one way of building resilience in vulnerable farming households. The aim of this study was to determine the secondary metabolite and mineral composition of noni juice obtained by fermenting the fruit of Morinda citrifolia L. Fruits were collected in August 2022 from the local field in Thiès region, West of Senegal. Extraction yields were determined and the secondary metabolites were determined using conventional analytical methods. Calcium, magnesium, iron, sodium and potassium were determined by atomic absorption spectrophotometer coupled with a CCD detector. The results show that an average fruit mass (503.2 ± 110.96 g) consists of 171.44 ± 50.01 g pulp and 34.06 ± 10.35 g seeds. The traditional extraction yield of noni juice is 16.46% after three weeks of fermentation. The contents of total polyphenols, flavonoids and tannins obtained in noni are 608.97 ± 4.53 mg EAG/100mL, 7.78 ± 0.01 mg EQ/100mL and 0.191 ± 0.01 mg EC/100mL respectively. The ethanol content of noni varies from 3.57 to 5.23 mL/100mL during extraction. Noni has a high calcium content with a concentration of 383.79 ± 33.23 mg/L. This is followed by a good concentration of magnesium, potassium and sodium, at 278.47 ± 26.30, 187.43 ± 10.7 and 155.95 ± 28.66 mg/L respectively. Noni also has an iron content of 202.15 ± 0.05 mg/L.
文摘Our previous study showed that the frictional drag decreases with increasing void fraction at Re〉1300, while it increases at Re 〈 1000. Decomposition of the Reynolds shear stress also implied that bubbles induce isotropy of turbulence. In order to confirm our previous analysis and to further investigate flow fields in the vicinity of bubbles, we analyze velocity fluctuations on the quadrant space in the streamwise and transverse directions （u′-v′ plane）. Here, we focus on two specific Reynolds numbers （at Re≈900 and ≈1410, which are close to the laminar-to-turbulent transition regime） and discuss bubble effects on sweep （u′〉 0, v′〈 0 ） and ejection （u′〈 0, v′〉 0） events as a function of the Reynolds number. We also illustrate velocity fluctuations in the vicinity of an individual bubble and a swarm of bubbles on the u′- v′ coordinates. The results show that a bubble swarm suppresses the velocity fluctuations at Re≈1410.
基金supported by KIST (2E31871 and 2E32591)and Innovation Fund Denmark Denmark (DANFLOW—project#9090-00059)Korea Institute for Advancement of Technology (KIAT)through the International Cooperative R&D program (Project No.P0018437)Basic Science Research Program through the National Research Foundation of Korea (NRF)funded by the Ministry of Education (2021R1A6A1A03039981).
文摘A novel polybenzimidazole(PBI)-based trilayer membrane assembly is developed for application in vanadium redox flow battery(VRFB).The membrane comprises a 1μm thin cross-linked poly[2,2′-(p-oxydiphenylene)−5,5′-bibenzimidazole](OPBI)sandwiched between two 20μm thick porous OPBI membranes(p-OPBI)without further lamination steps.The trilayer membrane demonstrates exceptional properties,such as high conductivity and low area-specific resistance(ASR)of 51 mS cm−1 and 81mΩcm^(2),respectively.Contact with vanadium electrolyte increases the ASR of trilayer membrane only to 158mΩcm^(2),while that of Nafion is 193mΩcm^(2).VO^(2+)permeability is 2.73×10^(-9) cm^(2) min^(−1),about 150 times lower than that of Nafion NR212.In addition,the membrane has high mechanical strength and high chemical stability against VO^(2+).In VRFB,the combination of low resistance and low vanadium permeability results in excellent performance,revealing high Coulombic efficiency(>99%),high energy efficiency(EE;90.8%at current density of 80mA cm^(−2)),and long-term durability.The EE is one of the best reported to date.
基金National Key Research and Development Program of China (No. 2017YFB0701600)National Natural Science Foundation of China (Nos. 11874036, 51622103, and 21573123)+2 种基金Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (No. 2017BT01N111)Shenzhen Projects for Basic Research (No. JCYJ20170412171430026)National Program for Thousand Young Talents of China.
文摘Developi ng alter native oxyge n reducti on reactio n (ORR) catalysts to replace precious Pt-based metals with abundant materials is the key challe nge of commercial application of fuel cells. Owing to their various compositi ons and tun able electronic properties, transition metal dichalcogenides (TMDs) have the great potential to realize high-efficiency catalysts for ORR. Here, various 3R-phase dichalcogenides of group VB and VIB transition metals (MX2, M = Nb, Ta, Mo, W;X = S, Se, Te) are investigated for ORR catalysts by using density functional theory calculations. The computed over-potentials of group VB TMDs are much less than those of group VIB TMDs. For group VB TMDs, a volcano-type plot of ORR catalytic activity is established on the adsorption energies of *OH, and NbS2 and TaTe2 exhibit best ORR activity with an oveepotential of 0.54 V. To achieve even better activity, strain engineering is performed to tune ORR catalytic activity, and the minimum over-potential of 0.43 V can be realized. We further dem on strate that the shift of p orbital center of surface chalcoge n elements under strain is responsible for tuning the catalytic activity of TMDs.
文摘The purpose of this study is to investigate the physicochemical properties of some local varieties of onion (Allium cepa L.) and compare them with an imported variety, all collected in May 2021. Proteins, reducing sugars, lipids, and polyphenol content were estimated according to the AFNOR standardized methods. The determination of calcium, magnesium, iron, sodium, potassium and phosphorus was performed by atomic absorption spectrophotometer coupled with a CCD detector. The results highlighted an average acidity of 0.377% ± 0.002% lower than the value of the imported variety which is 0.520% ± 0.001%. Local varieties have a pH ranging from 6.35 ± 0.003 to 6.42 ± 0.004, while the variety has a pH of 6.36 ± 0.003. The ash and dry matter contents vary respectively from 4.788% ± 0.004% to 8.253% ± 0.003% and 7.945% ± 0.021% to 11.945% ± 0.007% for the local varieties. Moreover, the imported one has ash and dry matter contents of 5.175% ± 0.007% and 10.035% ± 0.021% respectively. The results show that the protein, reducing sugar and lipid contents in the local onion varieties vary respectively from 2.815 ± 0.000 to 15.634 ± 0.001 g·100 g<sup>-1</sup>;4.691 ± 0.001 to 12.596 ± 0.002 g·100 g<sup>-1</sup> and 0.006 ± 0.001 to 0.050 ± 0.057 g·100 g<sup>-1</sup>. Furthermore, the imported variety has a protein, reducing sugar and lipid content of 5.649 ± 0.002;8.565 ± 0.002 g·100 g<sup>-1</sup> and 0.011 ± 0.010 g·100 g<sup>-1</sup> respectively. The maximum levels of total polyphenols are obtained in the imported variety, Bellani and Gandiol, respectively 9.973 ± 0.001, 4.535 ± 0.002, and 3.425 ± 0.006 mg EAG/g of dry matter. The local varieties have a significant calorific intake of between 35.451 ± 0.001 and 112.980 ± 0.003 kcal·100 g<sup>-1</sup> compared to the imported one with an energy value of 56.953 ± 0.001 kcal·100 g<sup>-1</sup> of dry matter. The bulbs of different onion varieties studied have a fairly high content of mineral elements. The potassium content of local varieties is
基金the financial support from the KIST Institution Program(No.2E32634)Basic Science Research Program through the National Research Foundation of Korea(NRF)grant funded by the Korea government(Ministry of Science and ICT)(Nos.NRF-2017R1A2B3002307 and NRF-2016M3A7B4900135)+1 种基金Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.NRF-2020R1A6A3A01099388)the National R&D Program through the National Research Foundation of Korea(NRF)funded by Ministry of Science and ICT(Nos.NRF-2022M3H4A1A04074153 and RS-2023-00239634).
文摘Mixed-dimensional composite structures using zero-dimensional(0D)quantum dots(QDs)and two-dimensional(2D)transition metal dichalcogenides(TMDs)materials are expected to attract great interest in optoelectronics due to the potential to generate new optical properties.Here,we report on the unique optical characteristics of a devices with mixed dimensional vertically stacked structures based on tungsten diselenide(WSe_(2))/CdSeS QDs monolayer/molybdenum disulfide(MoS_(2))(2D/0D/2D).Specifically,it exhibits an ambipolar photoresponse characteristic,with a negative photoresponse observed in the 400-600 nm wavelength range and a positive photoresponse appeared at 700 nm wavelength.It resulted in the high negative responsivity of up to 52.22 mA·W^(−1)under 400 nm,which is 163 times higher than that of the photodetector without CdSeS QDs.We also demonstrated the negative photoresponse,which could be due to increased carrier collision probability and non-radiative recombination.Device modeling and simulation reveal that Auger recombination among the types of non-radiative recombination is the main cause of negative photocurrent generation.Consequently,we discovered ambipolar photoresponse near a specific wavelength corresponding to the energy of quantum dots.Our study revealed interesting phenomenon in the mixed low-dimensional stacked structure and paved the way to exploit it for the development of innovative photodetection materials as well as for optoelectronic applications.
基金This work was financially supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(Nos.NRF-2020R1A5A1018153,NRF-2021R1A2C2010530,and 2020K1A3A1A74114847)This research was also supported by Technology R&D Project through the Korea Health Industry Development Institute(KHIDI),funded by the Ministry of Health&Wel-fare,Republic of Korea(No.HI21C0049010021).
文摘Core-shell-type bimetallic oxide and carbon composites comprising zinc oxide(ZnO)nanospheres and zinc manganese oxide(ZnMn_(2)O_(4))nanowires were produced by a hydrothermal method,and supersoni-cally sprayed together with reduced graphene oxide(rGO)nanosheets onto Ni foil to fabricate flexible su-percapacitors.The supersonic impact facilitated the exfoliation of the rGO nanosheets,thereby increasing the surface area and adhesion of the composite particles to the substrate.The rGO nanosheets were vertically aligned during the supersonic impact and formed localized zones,enabling optimal accommodation of the ZnO/ZnMn_(2)O_(4)particles.This localization,with the addition of rGO,reduced the agglomeration of ZnO/ZnMn_(2)O_(4)particles.The molar concentration of MnSO_(4)used in the synthesis of ZnO/ZnMn_(2)O_(4)was varied from 0.05 to 0.15 mol/L to determine the optimal MnSO_(4)concentration that would result in the highest energy storage capacitance.The unique nanostructure of ZnO/ZnMn_(2)O_(4)and the self-alignment of rGO sheets facilitated a favorable environment for high energy storage capability with a specific capaci-tance of 276.3 mF·cm^(−2)at a current density of 0.5 mA·cm^(−2)and an energy density of 98.2μWh·cm^(−2)at a power density of 1600μW·cm^(−2).The width of the potential window was increased to 1.2 V,imply-ing a significant increase in the energy storage capability of the supercapacitor.Capacitance retention of 88%was achieved after 10,000 charge/discharge cycles for the supercapacitor fabricated using an optimal MnSO_(4)concentration(0.10 mol/L)during the composite synthesis.
基金supported by Department of Science and Technology of Guangdong Province(No.211233812024)Guangdong Basic and Applied Basic Research Foundation(No.2021A1515110871)+1 种基金Shenzhen Science and Technology Program(Nos.JCYJ20220818101007016 and JCYJ20210324140804013)Tsinghua Shenzhen International Graduate School(No.QD2021005N).
文摘For anode-free lithium metal battery,lithiophilic surface modification on the current collector can effectively reduce the lithium nucleation barrier,so as to regulate the electrodeposition of lithium.Here,atomically dispersed Zn-(C/N/O)lithiophilic sites in the amorphous carbon medium were introduced onto Cu by an in-situ induced ion coordination chemistry strategy to get the modified Zn@NC@RGO@Cu current collector.X-ray absorption spectroscopy(XAS)combined with scanning transmission electron microscopy in high angle annular dark field(STEM-HAADF)analysis proved the single atomic state of the zinc sites surrounded by C,N,and O with a coordination number of~3.According to the electrochemical tests and first principle calculations,the ultra-uniformly dispersed Zn-(C/N/O)sites at the atomic level can effectively improve the lithium affinity,reduce the energy barrier for lithium nucleation,homogenize the lithium nucleation,and enhance an inorganic lithium compounds rich solid electrolyte interphase layer.As a result,the nucleation overpotential of lithium on the modified current collector was reduced to 7.7 mV,which was 5.4 times lower than that on bare Cu.Uniform lithium nucleation and deposition enabled stable Li plating/stripping and elevated Coulombic efficiency of 98.95%in Li||Cu cell after>850 cycles.Capacity retention of 89.7%was successfully achieved in the anode-free lithium metal battery after 100 cycles.
文摘Since trees and plants can absorb CO2, forests are widely regarded as a carbon sink that may control the amount of CO2 in the atmosphere. The CO2 uptake rate of plants is affected by the plant species and environmental conditions such as photosynthetically active radiation (PAR), temperature, water and nutrient contents. PAR is the most immediate environmental control on photosynthesis while air temperature affects both photorespiration and dark respiration. In the natural condition, PAR and temperature play an important role in net CO2 uptake. The effects of PAR and air temperature on the CO2 uptake of Pterocarpus macrocarpus grown in a natural habitat were studied in the present work. Due to many uncontrollable factors, a simple rectangular hyperbola could not represent the measured data. The data were divided into groups of 2oC intervals; CO2 uptake in each group may then be related to PAR by a rectangular hyperbola function. Using the obtained functions, the effect of PAR was removed from the original data. The PAR-independent CO2 uptake was then related to air temperature. Finally, the effects of PAR (I) and air temperature (Ta) on the CO2 uptake rate (A) were combined as: (-0.0575Ta2+2.6691Ta-23.264)I A= ——————————————— (-0.00766Ta2+0.40666Ta-3.99924) (-4.8794Ta2+227.13Ta-2456.9)+I
基金supported by institutional program grants from the Korea Institute of Science and Technology and Korea Institute of Energy Technology Evaluation and Planning(KETEP)granted financial resource from the Ministry of Trade,Industry&Energy,Republic of Korea(No.20224C10300020)“Carbon to X Project”(2020M3H7A1098229)through the National Research Foundation(NRF)funded by the Ministry of Science and ICT,Republic of Korea+1 种基金supported by the National Research Council of Science&Technology(NST)grant by the Korean government(MSIT)(No.CAP21011-100)National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(NRF-2021R1A2C2093467)。
文摘Introducing Ni in Ru oxide is a promising approach to enhance the catalytic activity for the oxygen evolution reaction(OER).However,the role of Ni(which has a poor intrinsic activity)is not fully understood.Here,a Ru NiO_(x)electrode fabricated via a modified dip coating method exhibited excellent OER performance in acidic media,and neutral media for CO_(2)reduction reaction.We combined in-situ/operando X-ray absorption near-edge structure and on-line inductively coupled plasma mass spectrometry studies to unveil the role of the Ni introduced in the Ru oxide.We propose that the Ni not only transforms the electronic structure of the Ru oxide,but also produces a large number of oxygen vacancies by distorting the oxygen lattice structure at low overpotentials,increasing the participation of lattice oxygen for OER.This work demonstrates the real behavior of bimetallic oxide materials under applied potentials and provides new insights into the development of efficient electrocatalysts.
基金financially supported by the National Natural Science Foundation of China (No. 51678182)the Start-up Grant for Shenzhen Oversea High-Level Talents。
文摘Combining metal to form metal phosphide is a promising strategy to address the fast capacity decay of P rooted from its low electronic conductivity and large volume changes upon cycling. Cu_(3)P, which possesses a high theoretical gravimetric and volumetric capacity of 363 m Ahág^(-1) and 1028 AháL^(-1) and reasonable volume expansion of 156% during sodiation, was investigated as anode material in SIBs. Hollow-structured Cu_(3)P electrode delivers an initial de-sodiation capacity of * 159.0 m Ahág^(-1) with high capacity retention of ~85.1% over 50 cycles at 0.2 C rate and exhibits good rate performance,retaining 70% of the capacity when the current density increases from 0.2 C to 1.6 C. A 3 V-class full cell consisting of P2-Na_(2/3) Ni_(1/3) Mn_(1/2) Ti_(1/6)O_(2) cathode and Cu_(3)P anode was also assembled, which could achieve an energy density of ~189.3 Whákg^(-1)(based on the mass of both electrode materials) and average discharge voltage of~2.91 V when cycled in 1.0-4.3 V at 0.1C.
基金This research was funded by the New&Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Eval-uation and Planning(KETEP),and supported by the ministry of Trade,Industry,Energy,of the Republic of Korea(No.20204010600470)Munho Kim acknowledges the support of Ministry of Education,Sin-gapore,under AcRF Tier 2(T2EP50120-0001)。
文摘Tandem solar cells are a key technology for exceeding the theoretical efficiency limit of single-junction cells.One of the most promising combinations is the silicon–perovskite tandem cells,considering their potential for high efficiency,fabrication on a large scale,and low cost.While most research focuses on improving each subcell,another key challenge lies in the tunnel junction that connects these subcells,significantly impacting the overall cell characteristics.Here,we demonstrate the first use of tunnel junctions using a stack of p+/n+polysilicon passivating contacts deposited directly on the tunnel oxide to overcome the drawbacks of conventional metal oxide-based tunnel junctions,including low tunneling efficiency and sputter damage.Using Random Forest analysis,we achieved high implied open circuit voltages over 700 mV and low contact resistivities of 500 mΩcm 2,suggesting fill factor losses of less than 1%abs for the operating conditions of a tandem cell.
文摘Ozone(O3)is widely used in drinking water disinfection and wastewater treatment.However,when applied to bromide-containing water,ozone induces the formation of bromate,which is carcinogenic.Our previous study found±at graphene oxide(GO)can enhance the degradation efficiency of micropollutants during ozonation.However,in this study,GO was found to promote bromate formation during ozonation of bromide-containing waters,with bromate yields from the O3/GO process more than twice those obtained using ozone alone.The promoted bromate formation was attributed to increased hydroxyl radical production,as confirmed by the significant reduction(almost 75%)in bromate yield after adding t-butanol(TBA).Cerium oxide(less tfian 5 mg/L)supported on reduced GO(xCeO2/RGO)significantly inhibited bromate formation during ozonation compared with reduced GO alone,and the optimal Ce atomic percentage(x)was determined to be 0.36%,achieving an inhibition rate of approximately 73%.Fourier transform infrared(FT-IR)spectra indicated the transformation of GO into RGO after hydrothermal treatment,and transmission electron microscope(TEM)results showed that CeO2 nanoparticles were well dispersed on the RGO surface.The X-ray photoelectron spectroscopy(XPS)spectra results demonstrated that the Ce^3+/Ce^4+ratio in xCeO2/RGO was almost 3-4 times higher than that in pure CeO2,which might be attributed to the charge transfer effect from GO to CeO2.Furthermore,Ce+on thexCeO2/RGO surface could quench Br-and BrO-to further inhibit bromate formation.Meanwhile,0.36CeO2/RGO could also enhance the degradation efficiency of N,N-diethyl-zn-toluamide(DEET)in synthetic and reclaimed water during ozonation.
基金supported by the New&Renewable Energy Core Technology Program of the Korea Institute of Energy Technology Evaluation and Planning(KETEP)granted financial resource from the Ministry of Trade,Industry&Energy(MOTIE),Republic of Korea(No.20213091010020)National Research Foundation of Korea(NRF)grant funded by the Korea Government(MSIT)(2020R1A2C1101085)+2 种基金the Korea Institute of Planning and Evaluation for Technology in Food,Agriculture and Forestry(IPET)and Korea Smart Farm R&D Foundation(KosFarm)through Smart Farm Innovation Technology Development Programfunded by the Ministry of Agriculture,Food and Rural Affairs(MAFRA)the Ministry of Science and ICT(MSIT),Rural Development Administration(RDA)(421036-03).
文摘Electron transport layer(ETL)is pivotal to charge carrier transport for PSCs to reach the Shockley-Queisser limit.This study provides a fundamental understanding of heterojunction electron transport layers(ETLs)at the atomic level for stable and efficient perovskite solar cells(PSCs).The bilayer structure of an ETL composed of SnO_(2) on TiO_(2) was examined,revealing a critical factor limiting its potential to obtain efficient performance.Alteration of oxygen vacancies in the TiO_(2) underlayer via an annealing process is found to induce manipulated band offsets at the interface between the TiO_(2) and SnO_(2) layers.In-depth electronic investigations of the bilayer structure elucidate the importance of the electronic properties at the interface between the TiO_(2) and SnO_(2) layers.The apparent correlation in hysteresis phenomena,including current density-voltage(J-V)curves,appears as a function of the type of band alignment.Density functional theory calculations reveal the intimate relationship between oxygen vacancies,deep trap states,and charge transport efficiency at the interface between the TiO_(2) and SnO_(2) layers.The formation of cascade band alignment via control over the TiO_(2) underlayer enhances device performance and suppresses hysteresis.Optimal performance exhibits a power conversion efficiency(PCE)of 23.45%with an open-circuit voltage(V_(oc))of 1.184 V,showing better device stability under maximum power point tracking compared with a staggered bilayer under one-sun continuous illumination.
