The concentrations of eight heavy metals （Cu, Zn, Pb, Cd, Cr, Ni, Hg, and As） in the intertidal surface sediments from Quanzhou Bay were determined to evaluate their levels and spatial distribution due to urbanizati...The concentrations of eight heavy metals （Cu, Zn, Pb, Cd, Cr, Ni, Hg, and As） in the intertidal surface sediments from Quanzhou Bay were determined to evaluate their levels and spatial distribution due to urbanization and economic development of Quanzhou region, southeast China. The ranges of the measured concentrations in the sediments are as follows： 24.8-119.7 mg/kg for Cu, 105.5-241.9 mg/kg for Zn, 34.3-100. 9 mg/kg for Pb, 0.28-0. 89 mg/kg for Cd, 51.1-121.7 mg/kg for Cr, 16.1-45.7 mg/kg for Ni, 0.17-0.74 mg/kg for Hg, and 17.7-30.2 mg/kg for As. The overall average concentrations of above metals exceed the primary standard criteria but meet the secondary standard criteria of the Chinese National Standard of Marine Sediment Quality. Several contents of Cu and Hg exceed the secondary standard criteria at some stations. The results of geoaccumulation index （Igeo） show that Cd causes strong pollution in most of the study area. There are no significant correlations among most of these heavy metals, indicating they have different anthropogenic and natural sources. Some locations present severe pollution by heavy metals depending on the sources, of which sewage outlets, aquatic breeding, and commercial ports are the main sources of contaminants to the area.展开更多
This study investigated effects of Ginsenoside Ro （Ro） on interleukin-1β （IL-1β）-induced apoptosis and inflammation in rat chondrocytes. The rat chondrocytes were co-treated with IL-1β （10 ng.kg^-1） and Ro （...This study investigated effects of Ginsenoside Ro （Ro） on interleukin-1β （IL-1β）-induced apoptosis and inflammation in rat chondrocytes. The rat chondrocytes were co-treated with IL-1β （10 ng.kg^-1） and Ro （50, 100 and 200 μmol.L^-1） for 48 h. Chondrocytes viability was detected by the MTT assay and Annexin V-FITC/PI dual staining assay. Caspase 3 activity was measured by using caspase 3 colorimetric assay kit. Apoptosis related proteins Bax, Bad, Bcl-XL, PCNA, p53 and phospho-p53, along with inflammation related protein MMP 3, MMP 9 and COX-2, and the expression of phospho-NF-κ3 p65 were assayed by western blotting analyses. Ro could improve IL-1β-induced chondrocytes viability. Ro could suppress IL-1β-induced apoptosis by inhibiting levels of Bax and Bad, decreasing p53 phosphorylation and promoting the expression of Bcl-XL and PCNA. Ro inhibited caspase 3 activity. IL-1β-induced inflammation and matrix degration were also alleviated by Ro with down-regulating the expression of MMP 3, MMP 9 and COX-2. Moreover, Ro inhibited NF-κ3 p65 phosphorylation induced by 1L-1β. In conclusion, these results suggested Ro exerted anti-apoptosis and anti-inflammation in IL-1β-induced rat chondrocytes, which might be related to NF-κ3 signal pathway. Therefore, we propose that Ro might be a potential novel drug for the treatment ofosteoarthritis.展开更多
Though the traditional energy regeneration system（ERS） which used a hydraulic motor and a generator in hybrid excavators can regenerate part of the energy, the power of the motor and the generator should be larger a...Though the traditional energy regeneration system（ERS） which used a hydraulic motor and a generator in hybrid excavators can regenerate part of the energy, the power of the motor and the generator should be larger and the time for regenerating energy is so short. At first, the structure of new ERS that combines the advantages of an electric and hydraulic accumulator is analyzed. The energy can be converted into both the electric energy and the hydraulic energy at the lowering of the boom and the generator can still works when the boom stops going down. Then, a method how to set the working pressure of the hydraulic accumulator is proposed. To avoid the excess loss, extra noise and shock pressure, a two-level pressure threshold method that the generator starts to work at the rising edge of the high pressure threshold and stops working at the falling edge of the low pressure threshold is presented to characterize the working mode of the generator. The control strategies on how to control the boom velocity at the lowering of the boom and how to improve the recovery efficiency when the boom stops going down are presented. The test bench of hybrid excavator with ERS is constructed, with which the studies on the influences of ERS on energy conversion efficiency and control performance are carried out. Experimental results show that the proposed ERS features better speed control performance of the boom than traditional ERS. It is also observed that an estimated 45% of the total potential energy could be regenerated at the lowering of the boom in the proposed ERS, and the power level of the generator and the hydraulic motor could be reduced by 60%. Hence, the proposed ERS has obvious advantages over the traditional ERS on the improvement of energy regeneration time, energy efficiency, control performance and economy.展开更多
Optical models directly effect the irradiance distribution of observed surface. Traditionally, approximate Lambertian models are widely used in designing the light-emitting diodes (LED) arrays in spite of their errors...Optical models directly effect the irradiance distribution of observed surface. Traditionally, approximate Lambertian models are widely used in designing the light-emitting diodes (LED) arrays in spite of their errors compared with the experimental data. But now a novel LED optical model for uniform illumination system has been proposed, in which the curvefitting technique is used to reduce the inherited errors and modify those previous models. The points from the curve of the LED light intensity are adopted, and a spline curve is designed for fitting, which obtains the revised mode. To verify its feasibility, we apply the new model in a 4×4 array design. The results show that compared with the approximate Lambertian, the light intensity distribution produced by the fitting model is more uniform and intense, as is expected.展开更多
The effect of screen length on the screening efficiency of particles is studied under various single parameter conditions including frequency, amplitude, vibration angle, and screen inclination. The Discrete Element M...The effect of screen length on the screening efficiency of particles is studied under various single parameter conditions including frequency, amplitude, vibration angle, and screen inclination. The Discrete Element Method (DEM) has been used to simulate the screening process. A functional relationship between screening efficiency and screen length is established. It is shown that screening efficiency and screen length have a complicated exponential relationship. Relationships between them are profoundly discussed and conclusions are easily drawn: low values of the parameters do not benefit screening; screening efficiency generally increases with screen length; screening efficiency reaches a plateau when these parameters are in range frequently encountered in practical applications.展开更多
Lithium metal batteries(LMBs)are considered the most promising energy stor-age devices for applications such as electrical vehicles owing to its tremendous theoretical capacity(3860 mAh g−1).However,the serious safety...Lithium metal batteries(LMBs)are considered the most promising energy stor-age devices for applications such as electrical vehicles owing to its tremendous theoretical capacity(3860 mAh g−1).However,the serious safety issues and poor cycling performance caused by the dendritic crystal growth during deposi-tion are concerned for any rechargeable batteries with a lithium metal anode.To make widespread adoption a possibility,considerable efforts have been devoted to suppressing lithium(Li)dendrite growth.In this review,the recent strategies to developing dendrite free Li anode,including constructing an artifi-cial solid electrolyte interface,current collector modification,separator film improvement,and electrolyte additive,are summarized.The merits and short-comings for different strategies are reviewed and a general summary and per-spective on the next generation rechargeable batteries are presented.展开更多
Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell(PSC) becomes a promising candidate for next-generation high-efficiency solar cells.The power conv...Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell(PSC) becomes a promising candidate for next-generation high-efficiency solar cells.The power conversion efficiency(PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)3 and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)3 solar cells and outline possible directions to further improve the device performance.展开更多
The discrete element method(DEM) has been widely used to simulate microscopic interactions between particles.Screening is a deeply complicated process when considering the law of motion for the particles,themselves.In...The discrete element method(DEM) has been widely used to simulate microscopic interactions between particles.Screening is a deeply complicated process when considering the law of motion for the particles,themselves.In this paper,a numerical model for the study of a particle screening process using the DEM is presented.Special attention was paid to the modeling of a vibrating screen that allows particles to pass through,or to rebound,when approaching the screen surface.Inferences concerning screen length and vibrating frequency as they relate to screening efficiency were studied.The conclusions were:three-dimensional simulation of screening efficiency along the screen length follows an exponential distribution;when the sieve vibrates over a certain frequency range the screening efficiency is stable;and,higher vibration frequencies can improve the handling capacity of the screening machine.展开更多
Recent studies have revealed that human sodium taurocholate cotransporting polypeptide （SLC10A1 or NTCP） is a functional cellular receptor for hepatitis B virus （HBV）. However, whether human NTCP can support HBV i...Recent studies have revealed that human sodium taurocholate cotransporting polypeptide （SLC10A1 or NTCP） is a functional cellular receptor for hepatitis B virus （HBV）. However, whether human NTCP can support HBV infection in mouse hepatocyte cell lines has not been clarified. Because an HBV-permissible mouse model would be helpful for the study of HBV pathogenesis, it is necessary to investigate whether human NTCP supports the susceptibility of mouse hepatocyte cell lines to HBV. The results show that exogenous human NTCP expression can render non-susceptible HepG2 （human）, Huh7 （human）, Hepal-6 （mouse）, AML-12 （mouse） cell lines and primary mouse hepatocyte （PMH） cells susceptible to hepatitis D virus （HDV） which employs HBV envelope proteins. However, human NTCP could only introduce HBV susceptibility in human-derived HepG2 and Huh7 cells, but not in mouse-derived Hepal-6, AML-12 or PMH cells. These data suggest that although human NTCP is a functional receptor that mediates HBV infection in human cells, it cannot support HBV infection in mouse hepatocytes. Our study indicated that the restriction of HBV in mouse hepatocytes likely occurs after viral entry but prior to viral transcription. We have excluded the role of mouse hepatocyte nuclear factors in the restriction of the HBV life cycle and showed that knockdown or inhibition of Sting, TBK1, IRF3 or IRF7, the components of the anti-viral signaling pathways, had no effect on HBV infection in mouse hepatocytes. Therefore, murine restriction factors that limit HBV infection need to be identified before a HBV-permissible mouse line can be created.展开更多
Geological disasters will happen in cold regions because of the effects of freeze-thaw cycles on rocks or soils, so studying the effects of these cycles on the mechanical characteristics and permeability properties of...Geological disasters will happen in cold regions because of the effects of freeze-thaw cycles on rocks or soils, so studying the effects of these cycles on the mechanical characteristics and permeability properties of rocks is very important. In this study, red sandstone samples were frozen and thawed with o, 4, 8 and 12 cycles, each cycle including 12 h of freezing and 12 h of thawing. The P-wave velocities of these samples were measured, and the mechanical properties and evolution of the steady-state permeabilities were investigated in a series of uniaxial and triaxial compression tests. Experimental results show that, with the increasing of cyclic freeze-thaw times, the P-wave velocity of the red sandstone decreases. The number of freeze-thaw cycles has a significant influence on the uniaxial compressive strength, elastic modulus, cohesion, and angle of internal friction. The evolution of permeability of the rock samples after cycles of freeze-thaw in a complete stress-strain process under triaxial compression is closely related to the variation of the microstructure in the rock. There is a highly corresponding relationship between volumetric strain and permeability with axial strain in all stages of the stress-strain behaviour.展开更多
A new vibration type and motion characteristics were proposed according to the principle of manual sie- ving. A mechanical model of the new motion was established and the characteristics of the new vibrating screen we...A new vibration type and motion characteristics were proposed according to the principle of manual sie- ving. A mechanical model of the new motion was established and the characteristics of the new vibrating screen were analyzed to establish its equation of motion by using the vibration theory, to include as tech- nological parameters, amplitude, movement velocity, and throwing index through theoretical calculation. The efficiency of particle screening was studied at different values of frequency and swing declination angle. The discrete element method （DEM） was used to simulate the screening with the swing trace. The functional relationship between screening efficiency and the parameters was fitted with the least square method. The results show that high frequency and large swing angle are suitable for small particles, while small values are suitable for particles close to the aperture size. Compared to the linear vibration trace, both screening efficiency and processing capacity were effectively improved.展开更多
AIM： TO investigate the inhibitory effect of kallistatin （KAL） on angiogenesis and HCT-116 xenograft tumor growth.METHODS： Heterotopic subcutaneous injection of 2 Seven days later, 2 x 1011 injected intratumorally...AIM： TO investigate the inhibitory effect of kallistatin （KAL） on angiogenesis and HCT-116 xenograft tumor growth.METHODS： Heterotopic subcutaneous injection of 2 Seven days later, 2 x 1011 injected intratumorally （n tumors were induced by x 106 HCT-11 cells in mice. rAAV-GFP or rAAV-KAL was = 5 for each group）. The mice were sacrificed at d 28, by which time the tumors in the rAAV-GFP group had grown to beyond 5% of the total body weight. Tumor growth was measured by calipers in two dimensions. Tumor angiogenesis was determined with tumor microvessel density （MVD） by immunohistology. Tumor cell proliferation was assessed by Ki-67 staining.RESULTS： Intratumor injection of rAAV-KAL inhibited tumor growth in the treatment group by 78% （171 ＋ 52 mm^3） at d 21 after virus infection compared to the control group （776 ＋ 241 mm^3）. Microvessel density was significantly inhibited in tumor tissues treated with rAAV-KAL, rAAV-KAL also decreased the proportion of proliferating cells （Ki-67 positive cells） in tumors compared with the control group.CONCLUSION： rAAV-mediated expression of KAL inhibits the growth of colon cancer by reducing angiogenesis and proliferation of tumor cells, and may provide a promising anti-angiogenesis-based approach to the treatment of metastatic colorectal cancer.展开更多
AIM:To investigate the effect of transgenic expression of kallistatin(Kal) on carbon tetrachloride(CCl 4)induced liver injury by intramuscular(im) electrotransfer of a Kal-encoding plasmid formulated with poly-Lglutam...AIM:To investigate the effect of transgenic expression of kallistatin(Kal) on carbon tetrachloride(CCl 4)induced liver injury by intramuscular(im) electrotransfer of a Kal-encoding plasmid formulated with poly-Lglutamate(PLG).METHODS:The pKal plasmid encoding Kal gene was formulated with PLG and electrotransferred into mice skeletal muscle before the administration of CCl 4.The expression level of Kal was measured.The serum biomarker levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST),malonyldialdehyde(MDA),and tumor necrosis factor(TNF)-α were monitored.The extent of CCl 4-induced liver injury was analyzed histopathologically.RESULTS:The transgene of Kal was sufficiently expressed after an im injection of plasmid formulated with PLG followed by electroporation.In the Kal gene-transferred mice,protection against CCl 4-induced liver injury was reflected by significantly decreased serum ALT,AST,MDA and TNF-α levels compared to those in control mice(P < 0.01 to 0.05 in a dose-dependent manner).Histological observations also revealed that hepatocyte necrosis,hemorrhage,vacuolar change and hydropic degeneration were apparent in mice after CCl 4 administration.In contrast,the damage was markedly attenuated in the Kal gene-transferred mice.The expression of hepatic fibrogenesis marker transforming growth factor-β1 was also reduced in the pKal transferred mice.CONCLUSION:Intramuscular electrotransfer of plasmid pKal which was formulated with PLG significantly alleviated the CCl 4-induced oxidative stress and inflammatory response,and reduced the liver damage in a mouse model.展开更多
The efficiency of particle screening was studied over a range of vibrational parameters including amplitude, frequency and vibrational direction. The Discrete Element Method (DEM) was used to simulate the screening pr...The efficiency of particle screening was studied over a range of vibrational parameters including amplitude, frequency and vibrational direction. The Discrete Element Method (DEM) was used to simulate the screening process. A functional relationship between efficiency and the parameters, both singly and combined, is established. The function is a complicated exponential. Optimal amplitude and frequency values are smaller for particles near the mesh and larger for other particles. The optimum vibration angle is 45° for nearly all kinds of particles. A transverse velocity, V⊥, was defined and V⊥=0.2 m/s was identified to be the most efficient operating point by both simulation and experimental observation. Comparison of these results with those reported by others is included.展开更多
As a novel advanced oxidation process (AOP), electro-Fenton process is powerful for degrading most organic compounds including toxic and non-biodegradable ones, and so has attracted great attention. This paper reviews...As a novel advanced oxidation process (AOP), electro-Fenton process is powerful for degrading most organic compounds including toxic and non-biodegradable ones, and so has attracted great attention. This paper reviews this process in detail including the mechanism, electrolytic bath, electrode materials, aerations and operation parameters. The application of electro-Fenton method in wastewater treatment is evaluated and summarized. Future work in this field is suggested, and three main directions of new electrode exploitation, development of assisted technologies and mechanistic study should be strengthened.展开更多
The propagation of polychromatic electromagnetic Gaussian Schell-model （EGSM） beams in free space is investigated. It is shown that the spectral degree of polarization, spectral degree of coherence, and normalized s...The propagation of polychromatic electromagnetic Gaussian Schell-model （EGSM） beams in free space is investigated. It is shown that the spectral degree of polarization, spectral degree of coherence, and normalized spectrum change generally on propagation. The conditions of keeping the spectral invariance and keeping polarization invariance for the polychromatic EGSM beams are derived respectively. The results indicate that the constraints on the parameters of EGSM source to keep polarization invariance on propagation are more rigorous than those to keep invariance of the normalized spectrum.展开更多
Landslide displacement prediction can enhance the efficacy of landslide monitoring system,and the prediction of the periodic displacement is particularly challenging.In the previous studies,static regression models(e....Landslide displacement prediction can enhance the efficacy of landslide monitoring system,and the prediction of the periodic displacement is particularly challenging.In the previous studies,static regression models(e.g.,support vector machine(SVM))were mostly used for predicting the periodic displacement.These models may have bad performances,when the dynamic features of landslide triggers are incorporated.This paper proposes a method for predicting the landslide displacement in a dynamic manner,based on the gated recurrent unit(GRU)neural network and complete ensemble empirical decomposition with adaptive noise(CEEMDAN).The CEEMDAN is used to decompose the training data,and the GRU is subsequently used for predicting the periodic displacement.Implementation procedures of the proposed method were illustrated by a case study in the Caojiatuo landslide area,and SVM was also adopted for the periodic displacement prediction.This case study shows that the predictors obtained by SVM are inaccurate,as the landslide displacement is in a pronouncedly step-wise manner.By contrast,the accuracy can be significantly improved using the dynamic predictive method.This paper reveals the significance of capturing the dynamic features of the inputs in the training process,when the machine learning models are adopted to predict the landslide displacement.展开更多
Novel cost-effective fuel cells have become more attractive due to the demands for rare and expensive platinum-group metal(PGM)catalysts for mitigating the sluggish kinetics of the oxygen reduction reaction(ORR).The h...Novel cost-effective fuel cells have become more attractive due to the demands for rare and expensive platinum-group metal(PGM)catalysts for mitigating the sluggish kinetics of the oxygen reduction reaction(ORR).The high-cost PGM catalyst in fuel cells can be replaced by earth-abundant transition-metalbased catalysts,that is,an Fe-N-C catalyst,which is considered one of the most promising alternatives.However,the performance of the Fe-N-C catalyst is hindered by the low catalytic activity and poor stability,which is caused by insufficient active sites and the lack of optimization of the triple-phase interface for mass transportation.Herein,a novel Fe–N–C catalyst consisting of mono-dispersed hierarchically mesoporous carbon sphere cores and single Fe atom-dispersed functional shells are presented.The synergistic effect between highly dispersed Fe-active sites and well-organized porous structures yields the combination of high ORR activity and high mass transfer performance.The half-wave potential of the catalyst in 0.1M H_(2)SO_(4) is 0.82 V versus reversible hydrogen electrode,and the peak power density is 812 mW·cm^(−2) in H_(2)–O_(2) fuel cells.Furthermore,it shows superior methanol tolerance,which is almost immune to methanol poisoning and generates up to 162 mW·cm^(−2) power density in direct methanol fuel cells.展开更多
A novel quadripolymer scale inhibitor poly-maleic anhydride-acrylic acid-acrylamide-sodium methallyl sulfonate(PMAAS)was synthesized by solution polymerization with maleic anhydride(MA),acrylic acid(AA), acrylamide(AM...A novel quadripolymer scale inhibitor poly-maleic anhydride-acrylic acid-acrylamide-sodium methallyl sulfonate(PMAAS)was synthesized by solution polymerization with maleic anhydride(MA),acrylic acid(AA), acrylamide(AM),sodium methallyl sulfonate(SMAS),etc.IR spectrum shows that PMAAS contains carbonyl, hydroxyl,phosphatic and sulfonic acid group.SEM indicates that PMAAS blocks the normal growth of scale CaCO3 and CaSO4 crystals.The influences of PMAAS concentration,Ca 2+ concentration,temperature and pH value of the system on the inhibition efficiency are investigated.The inhibition efficiency of PMAAS is superior to com- mercial inhibitors T-225 and XF-192.展开更多
基金supported by the National Natural Science Foundation of China(No.40673061)the Research Program of Science and Technology of Quanzhou City Government(No.2007Z43)the Foundation of Key Laboratory of Nuclear Resources and Environment(East China Institute of Technology),Ministry of Education(No.070714).
文摘The concentrations of eight heavy metals （Cu, Zn, Pb, Cd, Cr, Ni, Hg, and As） in the intertidal surface sediments from Quanzhou Bay were determined to evaluate their levels and spatial distribution due to urbanization and economic development of Quanzhou region, southeast China. The ranges of the measured concentrations in the sediments are as follows： 24.8-119.7 mg/kg for Cu, 105.5-241.9 mg/kg for Zn, 34.3-100. 9 mg/kg for Pb, 0.28-0. 89 mg/kg for Cd, 51.1-121.7 mg/kg for Cr, 16.1-45.7 mg/kg for Ni, 0.17-0.74 mg/kg for Hg, and 17.7-30.2 mg/kg for As. The overall average concentrations of above metals exceed the primary standard criteria but meet the secondary standard criteria of the Chinese National Standard of Marine Sediment Quality. Several contents of Cu and Hg exceed the secondary standard criteria at some stations. The results of geoaccumulation index （Igeo） show that Cd causes strong pollution in most of the study area. There are no significant correlations among most of these heavy metals, indicating they have different anthropogenic and natural sources. Some locations present severe pollution by heavy metals depending on the sources, of which sewage outlets, aquatic breeding, and commercial ports are the main sources of contaminants to the area.
基金supported by the Key Science and Technology Project of Fujian Province(No.2012Y0049)the Key Project of Quanzhou City Science and Technology Program(No.2011Z8)+1 种基金the Special Fund for Basic Scientific Research of Central Colleges,Huaqiao University(No.JB-SJ1012)the Science Foundation of Huaqiao University(No.10HZR28)
文摘This study investigated effects of Ginsenoside Ro （Ro） on interleukin-1β （IL-1β）-induced apoptosis and inflammation in rat chondrocytes. The rat chondrocytes were co-treated with IL-1β （10 ng.kg^-1） and Ro （50, 100 and 200 μmol.L^-1） for 48 h. Chondrocytes viability was detected by the MTT assay and Annexin V-FITC/PI dual staining assay. Caspase 3 activity was measured by using caspase 3 colorimetric assay kit. Apoptosis related proteins Bax, Bad, Bcl-XL, PCNA, p53 and phospho-p53, along with inflammation related protein MMP 3, MMP 9 and COX-2, and the expression of phospho-NF-κ3 p65 were assayed by western blotting analyses. Ro could improve IL-1β-induced chondrocytes viability. Ro could suppress IL-1β-induced apoptosis by inhibiting levels of Bax and Bad, decreasing p53 phosphorylation and promoting the expression of Bcl-XL and PCNA. Ro inhibited caspase 3 activity. IL-1β-induced inflammation and matrix degration were also alleviated by Ro with down-regulating the expression of MMP 3, MMP 9 and COX-2. Moreover, Ro inhibited NF-κ3 p65 phosphorylation induced by 1L-1β. In conclusion, these results suggested Ro exerted anti-apoptosis and anti-inflammation in IL-1β-induced rat chondrocytes, which might be related to NF-κ3 signal pathway. Therefore, we propose that Ro might be a potential novel drug for the treatment ofosteoarthritis.
基金supported by National Natural Science Foundation of China(Grant No. 50875233)National Hi-tech Research and Development Program of China(863 Program, Grant No. 2010AA044401)+3 种基金Open Fund of the State Key Lab of Flow Power Transmission and Control(Grant No. GZKF-201111)National Youth Science Foundofion of China(Grant No. 51205140)Fundamental Research Funds for the Central University of China(Grant No. JB-ZR1208)Scientific Research Funds of Huaqiao University, China(Grant No. 11BS409)
文摘Though the traditional energy regeneration system（ERS） which used a hydraulic motor and a generator in hybrid excavators can regenerate part of the energy, the power of the motor and the generator should be larger and the time for regenerating energy is so short. At first, the structure of new ERS that combines the advantages of an electric and hydraulic accumulator is analyzed. The energy can be converted into both the electric energy and the hydraulic energy at the lowering of the boom and the generator can still works when the boom stops going down. Then, a method how to set the working pressure of the hydraulic accumulator is proposed. To avoid the excess loss, extra noise and shock pressure, a two-level pressure threshold method that the generator starts to work at the rising edge of the high pressure threshold and stops working at the falling edge of the low pressure threshold is presented to characterize the working mode of the generator. The control strategies on how to control the boom velocity at the lowering of the boom and how to improve the recovery efficiency when the boom stops going down are presented. The test bench of hybrid excavator with ERS is constructed, with which the studies on the influences of ERS on energy conversion efficiency and control performance are carried out. Experimental results show that the proposed ERS features better speed control performance of the boom than traditional ERS. It is also observed that an estimated 45% of the total potential energy could be regenerated at the lowering of the boom in the proposed ERS, and the power level of the generator and the hydraulic motor could be reduced by 60%. Hence, the proposed ERS has obvious advantages over the traditional ERS on the improvement of energy regeneration time, energy efficiency, control performance and economy.
基金supported by the National Natural Science Foundation of China (No.60977068)the Science and Technology Key Project of Quanzhou (No.2009G9)
文摘Optical models directly effect the irradiance distribution of observed surface. Traditionally, approximate Lambertian models are widely used in designing the light-emitting diodes (LED) arrays in spite of their errors compared with the experimental data. But now a novel LED optical model for uniform illumination system has been proposed, in which the curvefitting technique is used to reduce the inherited errors and modify those previous models. The points from the curve of the LED light intensity are adopted, and a spline curve is designed for fitting, which obtains the revised mode. To verify its feasibility, we apply the new model in a 4×4 array design. The results show that compared with the approximate Lambertian, the light intensity distribution produced by the fitting model is more uniform and intense, as is expected.
基金the Special Topic Fund of Key Science and Technology of Fujian Province (No.2006HZ0002-2) for the financial support of these studies
文摘The effect of screen length on the screening efficiency of particles is studied under various single parameter conditions including frequency, amplitude, vibration angle, and screen inclination. The Discrete Element Method (DEM) has been used to simulate the screening process. A functional relationship between screening efficiency and screen length is established. It is shown that screening efficiency and screen length have a complicated exponential relationship. Relationships between them are profoundly discussed and conclusions are easily drawn: low values of the parameters do not benefit screening; screening efficiency generally increases with screen length; screening efficiency reaches a plateau when these parameters are in range frequently encountered in practical applications.
基金National Science Foundation,Grant/Award Numbers:1700785,1724941,1917577China Postdoctoral Science Foundation,Grant/Award Number:2020M671606+1 种基金National Natural Science Foundation of China,Grant/Award Numbers:21805221,21905221Natural Science Foundation of Jiangsu Province,Grant/Award Number:BK20191190。
文摘Lithium metal batteries(LMBs)are considered the most promising energy stor-age devices for applications such as electrical vehicles owing to its tremendous theoretical capacity(3860 mAh g−1).However,the serious safety issues and poor cycling performance caused by the dendritic crystal growth during deposi-tion are concerned for any rechargeable batteries with a lithium metal anode.To make widespread adoption a possibility,considerable efforts have been devoted to suppressing lithium(Li)dendrite growth.In this review,the recent strategies to developing dendrite free Li anode,including constructing an artifi-cial solid electrolyte interface,current collector modification,separator film improvement,and electrolyte additive,are summarized.The merits and short-comings for different strategies are reviewed and a general summary and per-spective on the next generation rechargeable batteries are presented.
基金the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51773045,21572041 and 21772030)for the financial support
文摘Owing to its nice performance, low cost, and simple solution-processing, organic-inorganic hybrid perovskite solar cell(PSC) becomes a promising candidate for next-generation high-efficiency solar cells.The power conversion efficiency(PCE) has boosted from 3.8% to 25.2% over the past ten years. Despite the rapid progress in PCE, the device stability is a key issue that impedes the commercialization of PSCs. Recently, all-inorganic cesium lead halide perovskites have attracted much attention due to their better stability compared with their organic-inorganic counterpart. In this progress report, we summarize the properties of CsPb(IxBr1-x)3 and their applications in solar cells. The current challenges and corresponding solutions are discussed. Finally, we share our perspectives on CsPb(IxBr1-x)3 solar cells and outline possible directions to further improve the device performance.
基金Project 2006HZ0002-2 supported by the Special Topic Fund of Key Science and Technology of Fujian Province
文摘The discrete element method(DEM) has been widely used to simulate microscopic interactions between particles.Screening is a deeply complicated process when considering the law of motion for the particles,themselves.In this paper,a numerical model for the study of a particle screening process using the DEM is presented.Special attention was paid to the modeling of a vibrating screen that allows particles to pass through,or to rebound,when approaching the screen surface.Inferences concerning screen length and vibrating frequency as they relate to screening efficiency were studied.The conclusions were:three-dimensional simulation of screening efficiency along the screen length follows an exponential distribution;when the sieve vibrates over a certain frequency range the screening efficiency is stable;and,higher vibration frequencies can improve the handling capacity of the screening machine.
文摘Recent studies have revealed that human sodium taurocholate cotransporting polypeptide （SLC10A1 or NTCP） is a functional cellular receptor for hepatitis B virus （HBV）. However, whether human NTCP can support HBV infection in mouse hepatocyte cell lines has not been clarified. Because an HBV-permissible mouse model would be helpful for the study of HBV pathogenesis, it is necessary to investigate whether human NTCP supports the susceptibility of mouse hepatocyte cell lines to HBV. The results show that exogenous human NTCP expression can render non-susceptible HepG2 （human）, Huh7 （human）, Hepal-6 （mouse）, AML-12 （mouse） cell lines and primary mouse hepatocyte （PMH） cells susceptible to hepatitis D virus （HDV） which employs HBV envelope proteins. However, human NTCP could only introduce HBV susceptibility in human-derived HepG2 and Huh7 cells, but not in mouse-derived Hepal-6, AML-12 or PMH cells. These data suggest that although human NTCP is a functional receptor that mediates HBV infection in human cells, it cannot support HBV infection in mouse hepatocytes. Our study indicated that the restriction of HBV in mouse hepatocytes likely occurs after viral entry but prior to viral transcription. We have excluded the role of mouse hepatocyte nuclear factors in the restriction of the HBV life cycle and showed that knockdown or inhibition of Sting, TBK1, IRF3 or IRF7, the components of the anti-viral signaling pathways, had no effect on HBV infection in mouse hepatocytes. Therefore, murine restriction factors that limit HBV infection need to be identified before a HBV-permissible mouse line can be created.
基金supported by the National Basic Research Program of China (973 Program) (Grant No. 2011CB013503)the National Natural Science Foundation of China (Grant No. 51374112)the Promotion Program for Young and Middle-aged Teacher in Science and Technology Research of Huaqiao University (ZQN-PY112)
文摘Geological disasters will happen in cold regions because of the effects of freeze-thaw cycles on rocks or soils, so studying the effects of these cycles on the mechanical characteristics and permeability properties of rocks is very important. In this study, red sandstone samples were frozen and thawed with o, 4, 8 and 12 cycles, each cycle including 12 h of freezing and 12 h of thawing. The P-wave velocities of these samples were measured, and the mechanical properties and evolution of the steady-state permeabilities were investigated in a series of uniaxial and triaxial compression tests. Experimental results show that, with the increasing of cyclic freeze-thaw times, the P-wave velocity of the red sandstone decreases. The number of freeze-thaw cycles has a significant influence on the uniaxial compressive strength, elastic modulus, cohesion, and angle of internal friction. The evolution of permeability of the rock samples after cycles of freeze-thaw in a complete stress-strain process under triaxial compression is closely related to the variation of the microstructure in the rock. There is a highly corresponding relationship between volumetric strain and permeability with axial strain in all stages of the stress-strain behaviour.
基金support from the National Natural Science Foundation of China(51175190)the Special Topic Fund of Key Science and Technology of Fujian Province(2006HZ0002-2)
文摘A new vibration type and motion characteristics were proposed according to the principle of manual sie- ving. A mechanical model of the new motion was established and the characteristics of the new vibrating screen were analyzed to establish its equation of motion by using the vibration theory, to include as tech- nological parameters, amplitude, movement velocity, and throwing index through theoretical calculation. The efficiency of particle screening was studied at different values of frequency and swing declination angle. The discrete element method （DEM） was used to simulate the screening with the swing trace. The functional relationship between screening efficiency and the parameters was fitted with the least square method. The results show that high frequency and large swing angle are suitable for small particles, while small values are suitable for particles close to the aperture size. Compared to the linear vibration trace, both screening efficiency and processing capacity were effectively improved.
基金Hong Kong University Foundation (special donation from Madame Cho So Man)Huaqiao University Foundation B105
文摘AIM： TO investigate the inhibitory effect of kallistatin （KAL） on angiogenesis and HCT-116 xenograft tumor growth.METHODS： Heterotopic subcutaneous injection of 2 Seven days later, 2 x 1011 injected intratumorally （n tumors were induced by x 106 HCT-11 cells in mice. rAAV-GFP or rAAV-KAL was = 5 for each group）. The mice were sacrificed at d 28, by which time the tumors in the rAAV-GFP group had grown to beyond 5% of the total body weight. Tumor growth was measured by calipers in two dimensions. Tumor angiogenesis was determined with tumor microvessel density （MVD） by immunohistology. Tumor cell proliferation was assessed by Ki-67 staining.RESULTS： Intratumor injection of rAAV-KAL inhibited tumor growth in the treatment group by 78% （171 ＋ 52 mm^3） at d 21 after virus infection compared to the control group （776 ＋ 241 mm^3）. Microvessel density was significantly inhibited in tumor tissues treated with rAAV-KAL, rAAV-KAL also decreased the proportion of proliferating cells （Ki-67 positive cells） in tumors compared with the control group.CONCLUSION： rAAV-mediated expression of KAL inhibits the growth of colon cancer by reducing angiogenesis and proliferation of tumor cells, and may provide a promising anti-angiogenesis-based approach to the treatment of metastatic colorectal cancer.
基金Supported by The State High Technology Research and Development Program of China (863 Program),No.2008AA02Z135the Important National Science and Technology Specific Projects,No.2009ZX09103-643the Natural Science Foundation of China,No.30973591
文摘AIM:To investigate the effect of transgenic expression of kallistatin(Kal) on carbon tetrachloride(CCl 4)induced liver injury by intramuscular(im) electrotransfer of a Kal-encoding plasmid formulated with poly-Lglutamate(PLG).METHODS:The pKal plasmid encoding Kal gene was formulated with PLG and electrotransferred into mice skeletal muscle before the administration of CCl 4.The expression level of Kal was measured.The serum biomarker levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST),malonyldialdehyde(MDA),and tumor necrosis factor(TNF)-α were monitored.The extent of CCl 4-induced liver injury was analyzed histopathologically.RESULTS:The transgene of Kal was sufficiently expressed after an im injection of plasmid formulated with PLG followed by electroporation.In the Kal gene-transferred mice,protection against CCl 4-induced liver injury was reflected by significantly decreased serum ALT,AST,MDA and TNF-α levels compared to those in control mice(P < 0.01 to 0.05 in a dose-dependent manner).Histological observations also revealed that hepatocyte necrosis,hemorrhage,vacuolar change and hydropic degeneration were apparent in mice after CCl 4 administration.In contrast,the damage was markedly attenuated in the Kal gene-transferred mice.The expression of hepatic fibrogenesis marker transforming growth factor-β1 was also reduced in the pKal transferred mice.CONCLUSION:Intramuscular electrotransfer of plasmid pKal which was formulated with PLG significantly alleviated the CCl 4-induced oxidative stress and inflammatory response,and reduced the liver damage in a mouse model.
基金the Special Topic of Key Science and Technology of Fujian Province Fund (No.2006HZ0002-2)
文摘The efficiency of particle screening was studied over a range of vibrational parameters including amplitude, frequency and vibrational direction. The Discrete Element Method (DEM) was used to simulate the screening process. A functional relationship between efficiency and the parameters, both singly and combined, is established. The function is a complicated exponential. Optimal amplitude and frequency values are smaller for particles near the mesh and larger for other particles. The optimum vibration angle is 45° for nearly all kinds of particles. A transverse velocity, V⊥, was defined and V⊥=0.2 m/s was identified to be the most efficient operating point by both simulation and experimental observation. Comparison of these results with those reported by others is included.
基金Project supported by the National Natural Science Foundation of China (No. 50478049)the Natural Science Foundation of Guangdong Province (No. 04011215), China
文摘As a novel advanced oxidation process (AOP), electro-Fenton process is powerful for degrading most organic compounds including toxic and non-biodegradable ones, and so has attracted great attention. This paper reviews this process in detail including the mechanism, electrolytic bath, electrode materials, aerations and operation parameters. The application of electro-Fenton method in wastewater treatment is evaluated and summarized. Future work in this field is suggested, and three main directions of new electrode exploitation, development of assisted technologies and mechanistic study should be strengthened.
基金I am indebted to Prof. Emil Wolf at the University of Rochester (USA) for his helpful discussions and encouragement. This work was supported by the National Natural Science Foundation of China under Grant No.60477041.
文摘The propagation of polychromatic electromagnetic Gaussian Schell-model （EGSM） beams in free space is investigated. It is shown that the spectral degree of polarization, spectral degree of coherence, and normalized spectrum change generally on propagation. The conditions of keeping the spectral invariance and keeping polarization invariance for the polychromatic EGSM beams are derived respectively. The results indicate that the constraints on the parameters of EGSM source to keep polarization invariance on propagation are more rigorous than those to keep invariance of the normalized spectrum.
基金The authors appreciate the financial support provided by the Natural Science Foundation of China(No.41807294)This study was also financially supported by China Geological Survey Project(Nos.DD20190716 and 0001212020CC60002)。
文摘Landslide displacement prediction can enhance the efficacy of landslide monitoring system,and the prediction of the periodic displacement is particularly challenging.In the previous studies,static regression models(e.g.,support vector machine(SVM))were mostly used for predicting the periodic displacement.These models may have bad performances,when the dynamic features of landslide triggers are incorporated.This paper proposes a method for predicting the landslide displacement in a dynamic manner,based on the gated recurrent unit(GRU)neural network and complete ensemble empirical decomposition with adaptive noise(CEEMDAN).The CEEMDAN is used to decompose the training data,and the GRU is subsequently used for predicting the periodic displacement.Implementation procedures of the proposed method were illustrated by a case study in the Caojiatuo landslide area,and SVM was also adopted for the periodic displacement prediction.This case study shows that the predictors obtained by SVM are inaccurate,as the landslide displacement is in a pronouncedly step-wise manner.By contrast,the accuracy can be significantly improved using the dynamic predictive method.This paper reveals the significance of capturing the dynamic features of the inputs in the training process,when the machine learning models are adopted to predict the landslide displacement.
基金We gratefully acknowledge support from the National Natural Science Foundation of China(Grant Nos.21905220,51772240,21503158,51425301,U1601214,21703184)the China Postdoctoral Science Foundation(2020M673408)+5 种基金the Key Research and Development Plan of Shaanxi Province,China(Grant No.2018ZDXM-GY-135)the Fundamental Research Funds for“Young Talent Support Plan”of Xi'an Jiaotong University(HG6J003)the“1000‐Plan program”of Shaanxi Province,the Promotion Program for Young and Middle-Aged Teacher in Science and Technology Research of Huaqiao University(ZQN-PY506)the Scientific Research Funds of Huaqiao University(17BS405)the State Key Laboratory for Mechanical Behavior of Materials(20192101)the Natural Science Foundation Committee of Jiangsu Province(BK20201190).
文摘Novel cost-effective fuel cells have become more attractive due to the demands for rare and expensive platinum-group metal(PGM)catalysts for mitigating the sluggish kinetics of the oxygen reduction reaction(ORR).The high-cost PGM catalyst in fuel cells can be replaced by earth-abundant transition-metalbased catalysts,that is,an Fe-N-C catalyst,which is considered one of the most promising alternatives.However,the performance of the Fe-N-C catalyst is hindered by the low catalytic activity and poor stability,which is caused by insufficient active sites and the lack of optimization of the triple-phase interface for mass transportation.Herein,a novel Fe–N–C catalyst consisting of mono-dispersed hierarchically mesoporous carbon sphere cores and single Fe atom-dispersed functional shells are presented.The synergistic effect between highly dispersed Fe-active sites and well-organized porous structures yields the combination of high ORR activity and high mass transfer performance.The half-wave potential of the catalyst in 0.1M H_(2)SO_(4) is 0.82 V versus reversible hydrogen electrode,and the peak power density is 812 mW·cm^(−2) in H_(2)–O_(2) fuel cells.Furthermore,it shows superior methanol tolerance,which is almost immune to methanol poisoning and generates up to 162 mW·cm^(−2) power density in direct methanol fuel cells.
基金Supported by the National Natural Science Foundation of China （No.50082003） and the Provincial Natural Science Foundation of Fujian （No.E0210023）.
文摘A novel quadripolymer scale inhibitor poly-maleic anhydride-acrylic acid-acrylamide-sodium methallyl sulfonate(PMAAS)was synthesized by solution polymerization with maleic anhydride(MA),acrylic acid(AA), acrylamide(AM),sodium methallyl sulfonate(SMAS),etc.IR spectrum shows that PMAAS contains carbonyl, hydroxyl,phosphatic and sulfonic acid group.SEM indicates that PMAAS blocks the normal growth of scale CaCO3 and CaSO4 crystals.The influences of PMAAS concentration,Ca 2+ concentration,temperature and pH value of the system on the inhibition efficiency are investigated.The inhibition efficiency of PMAAS is superior to com- mercial inhibitors T-225 and XF-192.
