We previously performed transcriptome sequencing and found that genes for matrix metalloproteinases（MMPs）,such as MMP7 and 12,seem to be highly upregulated following peripheral nerve injury,and may be involved in ne...We previously performed transcriptome sequencing and found that genes for matrix metalloproteinases（MMPs）,such as MMP7 and 12,seem to be highly upregulated following peripheral nerve injury,and may be involved in nerve repair.In the present study,we systematically determined the expression levels of MMPs and their regulators at 1,4,7 and 14 days after sciatic nerve crush injury.The number of differentially expressed genes was elevated at 4 and 7 days after injury,but decreased at 14 days after injury.Among the differentially expressed genes,those most up-regulated showed fold changes of more than 214,while those most down-regulated exhibited fold changes of more than 2-10.Gene sequencing showed that,at all time points after injury,a variety of MMP genes in the “Inhibition of MMPs” pathway were up-regulated,and their inhibitor genes were down-regulated.Expression of key up-and down-regulated genes was verified by quantitative real-time polymerase chain reaction analysis and found to be consistent with transcriptome sequencing.These results suggest that MMP-related genes are strongly involved in the process of peripheral nerve regeneration.展开更多
We studied the effects of sintering temperature on FeCuCo based pre-alloyed powder for diamond bits.The FeCuCo composite was fabricated by co-precipitation method.With the addition of tungsten carbide（WC）,sintering ...We studied the effects of sintering temperature on FeCuCo based pre-alloyed powder for diamond bits.The FeCuCo composite was fabricated by co-precipitation method.With the addition of tungsten carbide（WC）,sintering under different temperatures was investigated.Mechanical properties of the FeCuCo based matrix were systematically studied.The structure of the composite was evaluated by X-ray diffraction（XRD） and scanning electron microscope（SEM） was used to analyze the surface of the powder and matrix.The suitable sintering temperature was determined through differential scanning calorimeter（DSC）.Micro drilling experiments were performed,and 820 ℃ was identified to be the ideal sintering temperature,at which the matrix shows the best mechanical properties and drilling performance.展开更多
PEG-related adhesives are limited in clinical use because they are easy to swell and cannot support the cell growth. In this study, we produced a series of POSS-modified PEG adhesives with high adhesive strength. Intr...PEG-related adhesives are limited in clinical use because they are easy to swell and cannot support the cell growth. In this study, we produced a series of POSS-modified PEG adhesives with high adhesive strength. Introduction of inorganic hydrophobic POSS units decreased the swelling of the adhesives and enhanced cell adhesion and growth. The in vitro cytotoxicity and in vivo inflammatory response experiments clearly demonstrated that the adhesives were nontoxic and possessed excellent biocompatibility. Compared with the sutured wounds, the adhesive-treated wounds showed an accelerated healing process in wounded skin model of the Bama miniature pig, demonstrating that the POSS-modified PEG adhesive is a promising candidate for wound closure.展开更多
Wallerian degeneration is a critical biological process that occurs in distal nerve stumps after nerve injury. To systematically investigate molecular changes underlying Wallerian degeneration, we used a rat sciatic n...Wallerian degeneration is a critical biological process that occurs in distal nerve stumps after nerve injury. To systematically investigate molecular changes underlying Wallerian degeneration, we used a rat sciatic nerve transection model to examine microarray analysis outcomes and investigate significantly involved Kyoto Enrichment of Genes and Genomes（KEGG） pathways in injured distal nerve stumps at 0, 0.5, 1, 6, 12, and 24 hours, 4 days, 1, 2, 3, and 4 weeks after peripheral nerve injury. Bioinformatic analysis showed that only one KEGG pathway（cytokine-cytokine receptor interaction） was significantly enriched at an early time point（1 hour post-sciatic nerve transection）. At later time points, the number of enriched KEGG pathways initially increased and then decreased. Three KEGG pathways were studied in further detail： cytokine-cytokine receptor interaction, neuroactive ligand-receptor interaction, and axon guidance. Moreover, temporal expression patterns of representative differentially expressed genes in these KEGG pathways were validated by real time-polymerase chain reaction. Taken together, the above three signaling pathways are important after sciatic nerve injury, and may increase our understanding of the molecular mechanisms underlying Wallerian degeneration.展开更多
After annealing the solution cast P（VDF-TrFE） films at elevated temperatures, which were synthesized via a full hydrogenation process from P（VDF-CTFE） with a composition of VDF/TrFE = 80/20（mol%）, a series of P...After annealing the solution cast P（VDF-TrFE） films at elevated temperatures, which were synthesized via a full hydrogenation process from P（VDF-CTFE） with a composition of VDF/TrFE = 80/20（mol%）, a series of P（VDF-TrFE） films were fabricated in present work. The crystalline and ferroelectric phases of the films were carefully characterized and their dielectric, ferroelectric and piezoelectric properties were systematically investigated. The improved crystalline and ferroelectric phases in the films induced by annealing at elevated temperatures are responsible for the significant improved electric properties of the films. The optimized annealing temperature is found to be 130 ℃ and the best performance including the highest dielectric constant of 12.5 at 1 kHz, the largest maximum polarization of 11.21 μC/cm^2 and remnant polarization of 7.22 μC/cm^2, the lowest coercive electric field of 56 MV/m, and the highest piezoelectric coefficient of -25 pC/N is observed.展开更多
Two pairs of amino-acid functionalized poly（3,4-ethylenedioxythiophene）（PEDOT） derivatives, namely, poly（N-（tert-butoxycarbonyl）-L-methionyl（3,4-ethylenedioxythiophene-2＇-yl）methylamide）（L-PEDOT-Boc-Met） ...Two pairs of amino-acid functionalized poly（3,4-ethylenedioxythiophene）（PEDOT） derivatives, namely, poly（N-（tert-butoxycarbonyl）-L-methionyl（3,4-ethylenedioxythiophene-2＇-yl）methylamide）（L-PEDOT-Boc-Met） and poly（N-（tertbutoxycarbonyl）-D-methionyl（3,4-ethylenedioxythiophene-2＇-yl）methylamide）（D-PEDOT-Boc-Met）; poly（L-methionyl（3,4-ethylenedioxythiophene-2＇-yl）methylamide）（L-PEDOT-Met） and poly（D-methionyl（3,4-ethylenedioxythiophene-2＇-yl）methylamide）（D-PEDOT-Met） were synthesized via chemical oxidative polymerization of corresponding monomers. The structural characterization, spectroscopic properties and thermal stability of these monomers and polymers were systematically explored by FTIR spectra, Raman spectra, XRD spectra, UV-Vis spectra and thermogravimetric analysis. As chiral electrode materials, these polymers were employed to successfully recognize 3,4-dihydroxyphenylalanine（DOPA） enantiomers by cyclic voltammetry（CV） in sulphuric acid solution. The measurement results reveal that the tendency was hetero-chiral interaction between L-PEDOT-Met/PVA/GCE and D-DOPA, D-PEDOT-Met/PVA/GCE and L-DOPA, respectively. Also, the mechanism of chiral discrimination was discussed. All the results implied that the combination of electrochemical molecular recognition technology and chiral PEDOT materials can be a promising approach for chiral recognition and may open new opportunities for facile, biocompatible, sensitive and robust chiral assays in biochemical applications.展开更多
A new low-cost corrosion-resistant rebar（HRB400R）was designed and fabricated by Cr micro-alloying.The HRB400 Rrebar had uniform distribution of Cr element in ferrite grains.The corrosion behavior of the rebar in the...A new low-cost corrosion-resistant rebar（HRB400R）was designed and fabricated by Cr micro-alloying.The HRB400 Rrebar had uniform distribution of Cr element in ferrite grains.The corrosion behavior of the rebar in the neutral Cl^--containing environment was studied systematically,and the improved corrosion resistance of the HRB400 Rrebar was revealed.According to the corrosion-morphology observation and electrochemical monitoring during the constant immersion corrosion in the 3.5mass% NaCl solution,the HRB400 Rrebar presented alleviated corrosion damage,nobler Ecorr,lower Icorr,and larger Rtvalues,and these phenomena were more remarkable in the initial corrosion period.The elevated electrode potential of the rebar,caused by the solid-solution of Cr micro-alloying in the ferrite grains,was the key to the corrosion-resistance improvement.The HRB400 Rrebar also presented much lower mass-loss rate in the salt spray corrosion test.Besides the elevated corrosion resistance of the matrix,the doping and enrichment of Cr element in the rust layer was another factor for the higher corrosion resistance,which retarded the penetration of aggressive medium through the rust layer.展开更多
Droplet migration in plane Poiseuille flow is numerically investigated with a dissipative particle dynamics method.The single droplet deformation in the channel flow is first studied to verify the current method and t...Droplet migration in plane Poiseuille flow is numerically investigated with a dissipative particle dynamics method.The single droplet deformation in the channel flow is first studied to verify the current method and the physical model.The effect of the viscosity ratio between the droplet and the solvent and the effect of the confinement are systematically investigated.The droplet is in an off-centerline equilibrium position with a specific selection of the parameters.A large viscosity ratio makes the droplet locate in a near-wall equilibrium position,and a large capillary number makes the droplet migrate to the near-centerline region of the channel.For the droplet migration at the same Capillary number,there is a critical width of the channel,which is less than twice of the droplet diameter,and the droplet will only migrate to the channel centerline if the width is less than this critical value.展开更多
Flexible electrochemical capacitors（ECs） are vitally important as the emerging flexible electronics.We have prepared polypyrrole doped with counter ion of Cl-on carbon fibers（PPy-Cl/CFs） via the simple electrochem...Flexible electrochemical capacitors（ECs） are vitally important as the emerging flexible electronics.We have prepared polypyrrole doped with counter ion of Cl-on carbon fibers（PPy-Cl/CFs） via the simple electrochemical deposition method.The flexible ECs based on PPy-Cl/CFs electrodes have been assembled by using H_3PO_4/poly（vinyl alcohol）（PVA）,H_2SO_4/PVA,LiClO_4/PVA,KCl/PVA and Li Cl/PVA as gel electrolytes.The capacitive properties of ECs have been systematically evaluated with electrochemical methods.The results show that the cells with H_3PO_4/PVA electrolyte exhibit good cyclic stability（91.5% retention after 15000 cycles） although PPy-Cl/CFs has moderate specific capacitance in H_3PO_4/PVA（41.6 m F·cm^-1 or 52.0 F·cm^-3）.However,the ECs in other electrolytes have poor cyclic stability.Further electrochemical analysis reveals that the doping/dedoping processes of PPy-Cl/CFs are different in the five electrolytes,and X-ray photoelectron spectra demonstrate that the ratios of counter anions in PPy＇s oxidized states to those in reduced states are obviously different when PPy-Cl/CFs are kept in reduced or oxidized states in the five electrolytes.The results also illustrate why the capacitors using H_3PO_4/PVA as electrolyte exhibit good cyclic stability.Furthermore,a light emitting diode（LED） with a threshold voltage of 2.5 V can be lighted by three ECs connected in series.展开更多
Luminescent solar concentrators（LSC） can reduce the area of solar cells by collecting light from a large area and concentrating the captured light onto relatively small area photovoltaic（PV） cells, and thereby red...Luminescent solar concentrators（LSC） can reduce the area of solar cells by collecting light from a large area and concentrating the captured light onto relatively small area photovoltaic（PV） cells, and thereby reducing the cost of PV electricity generation. LSCs with bottom-facing cells（BMP-LSC） can collect both direct light and indirect light, so further improving the efficiency of the PV cells. However, it is hard to analyze the effect of each parameter by experiment because there are too many parameters involved in the BMP-LSC. In this paper, all the physical processes of the light transmission and collection in the BMP-LSC were analyzed. A three-dimensional Monte Carlo ray tracing program was developed to study the transmission of photons in the LSC. A larger-size LSC was simulated, and the effects of dye concentration, the LSC thickness, the cell area, and the cell distance were systematically analyzed.展开更多
Eu^3＋/Dy^3＋ single-doped and co-doped 6SrO-3Al2O3-91SiO2 and 12SrO-6Al2O3-82SiO2 glass and glass-ceramics were synthesized successfully by a sol-gel method. The prepared samples were characterized by the X-ray diffr...Eu^3＋/Dy^3＋ single-doped and co-doped 6SrO-3Al2O3-91SiO2 and 12SrO-6Al2O3-82SiO2 glass and glass-ceramics were synthesized successfully by a sol-gel method. The prepared samples were characterized by the X-ray diffraction, high-resolution transmission electron microscopy, photoluminescent spectra and X-ray photoelectron spectroscopy. The effect of annealing temperature, doped ions and matrix component on the structure and the photoluminescent characteristics was systematically studied. The higher temperature was helpful to form nanocrystals and the amount of SrO and Al2O3 could better disperse the rare earth ions in matrix at suitable temperature, and both of them could improve the luminescent intensity. Meanwhile, the doped ions could change the luminescent color by single, codoped and energy transfer. The Sr2SiO4 nanocrystals were observed in silicates glasses and became larger with the increase of the annealing temperature and the luminous efficiency of rare-earth（RE） ions could be enhanced when the samples changed from glass state to glass-ceramic state. The results indicated that the photoluminescent properties could be changed through controlling the doped ions, annealing temperature and matrix component.展开更多
The influence of sodium dodecyl sulfate（SDS） on the cloud point temperature（Tcp） of the aqueous solution of thermoresponsive hyperbranched polyethylenimine derivative HPEI-IBAm was studied systematically. When pH ...The influence of sodium dodecyl sulfate（SDS） on the cloud point temperature（Tcp） of the aqueous solution of thermoresponsive hyperbranched polyethylenimine derivative HPEI-IBAm was studied systematically. When pH was below 8.5, HPEI-IBAm was positively-charged. Initially, the Tcp of HPEI-IBAm decreased significantly, followed by an obvious increase with the increase of SDS concentration. The lower the pH was, the higher the SDS concentration was required to achieve the minimum Tcp. When pH was above 8.5, HPEI-IBAm was neutral and raising the SDS concentration led to the gradual increase of Tcp. Compared to linear poly（N-isopropyl acrylamide）（PNIPAm）, the Tcp of the current hyperbranched HPEI-IBAm was more sensitive to SDS. The thermoresponsive HPEI-IBAm/SDS complex was used as host to accommodate the non-polar pyrene in water. The lowest SDS concentration for effectively enhancing the solubility of pyrene in water was around 6.4 mmol·L^-1. When HPEI-IBAm was present, the SDS concentration threshhold was decreased to about 0.31 mmol·L^-1. Fluorescence technique with pyrene as the hydrophobic probe demonstrated that the SDS concentration of 7.2 mmol·L^-1 was required to form the hydrophobic domain to accommodate pyrene guests without HPEI-IBAm, while only 0.2 mmol·L^-1 of SDS was required in the presence of HPEI-IBAm.展开更多
Sum frequency generation spectroscopy（SFG） has been widely used to study the interfacial chemistry of aqueous salt solutions of biological or environmental importance. Most of the SFG data analysis used the same bul...Sum frequency generation spectroscopy（SFG） has been widely used to study the interfacial chemistry of aqueous salt solutions of biological or environmental importance. Most of the SFG data analysis used the same bulk refractive index for different salt concentrations despite of the variations of the refractive indices. Here we systematically investigate the influence of the refractive index on the SFG intensities at various experimental conditions. It is discovered that the SFG intensities are the most sensitive to the refractive index at solid/liquid interfaces nearby the total internal reflection geometries. At air/liquid interfaces, the effect of the refractive indices is also nonegligible. Consequently some important SFG results, such as the response of water structures to the ionic strength at the SiO2/aqueous interfaces, are necessary to be reevaluated. These conclusions on the effect of the small variations of the refractive index are generally useful for the common practice of SFG data analysis.展开更多
Due to high reflectivity and high resolution of X-ray pulses, diamond is one of the most popular Bragg crystals serving as the reflecting mirror and mono-chromator in the next generation of free electron lasers（FELs...Due to high reflectivity and high resolution of X-ray pulses, diamond is one of the most popular Bragg crystals serving as the reflecting mirror and mono-chromator in the next generation of free electron lasers（FELs）.The energy deposition of X-rays will result in thermal heating, and thus lattice expansion of the diamond crystal,which may degrade the performance of X-ray FELs. In this paper, the thermal loading effect of diamond crystal for X-ray FEL oscillators has been systematically studied by combined simulation with Geant4 and ANSYS, and its dependence on the environmental temperature, crystal size, X-ray pulse repetition rate and pulse energy are presented. Our results show that taking the thermal loading effects into account, X-ray FEL oscillators are still robust and promising with an optimized design.展开更多
Doppler broadening and coincidence Doppler broadening of annihilation radiation experiments have been performed in three kinds of polyethylene glycol（PEG） membrane formed with different average molecular weight usin...Doppler broadening and coincidence Doppler broadening of annihilation radiation experiments have been performed in three kinds of polyethylene glycol（PEG） membrane formed with different average molecular weight using the tunable monoenergy slow positron probe as a function of implantion energy. The obtained positron annihilation parameters are interpreted from two aspects： surface effect and differences in micro-structure or chemical environment of positron annihilation. The experimental results show that the regulation of densification of PEG molecular packing and distribution uniformity from the near surface layer to the bulk region in the film forming process can be well realized by changing its molecular weight. Combining a variable monoenergetic slow positron beam and these two positron annihilation spectroscopy methods is a powerful tool to study positron annihilation characteristics and for polymeric thin-film fine structure analysis.展开更多
The polymorphisms of toll-like receptor（TLR） have been hypothesized to affect the tuberculosis susceptibility. However, the direct evidence remains controversial. Here we performed a comprehensive meta-analysis to s...The polymorphisms of toll-like receptor（TLR） have been hypothesized to affect the tuberculosis susceptibility. However, the direct evidence remains controversial. Here we performed a comprehensive meta-analysis to summarize the associations between TLR polymorphisms and tuberculosis susceptibility. We systematically searched the Pub Med, Embase, Cochrane library, and Chinese National Knowledge Infrastructure up to April 25, 2014. Case-control studies investigating TLR polymorphisms and tuberculosis susceptibility were included in the meta-analysis. Pooled odds ratios and corresponding 95% confidence intervals were calculated for cases and controls. Stata 11.0 and Review Manager 5.1 were adopted to conduct statistical analysis. We included 29 studies, involving 17 804 individuals. The results revealed an obvious increase of tuberculosis risk in TLR2 2258 AA, and decreased risk in TLR6 745 TT and TLR8 rs3761624 GA genotypes. Meanwhile, different genetic models were performed. TLR8 rs3764879 C, TLR8 rs3761624 A and TLR8 rs3764880 A alleles were associated with high susceptibility, while TLR6 745 T and TLR8 rs3788935 C alleles were protective. Other polymorphisms, including TLR9 1486C/T, did not show significant associations with tuberculosis infection. Finally, subgroup analysis in TLR8 rs3764880 according to gender found a slight elevated effect of A allele in males. The meta-analysis suggests significant associations between several TLR polymorphisms and tuberculosis, including TLR2 2258G/A, TLR6 745C/T, TLR8 rs3761624, TLR8 rs3764879, TLR8 rs3761624 and TLR8 rs3764880. This study serves as the framework for additional studies to determine further the role of TLRs in tuberculosis infection.展开更多
基金supported by the Natural Science Foundation of Jiangsu Province of China,No.BK20150409the Natural Science Foundation of Jiangsu Higher Education Institutions of China,No.15KJB180013+2 种基金the Scientific Research Foundation of Nantong University in China,No.14R29the Natural Science Foundation of Nantong City in China,No.MS12015043the Priority Academic Program Development of Jiangsu Higher Education Institutions in China
文摘We previously performed transcriptome sequencing and found that genes for matrix metalloproteinases（MMPs）,such as MMP7 and 12,seem to be highly upregulated following peripheral nerve injury,and may be involved in nerve repair.In the present study,we systematically determined the expression levels of MMPs and their regulators at 1,4,7 and 14 days after sciatic nerve crush injury.The number of differentially expressed genes was elevated at 4 and 7 days after injury,but decreased at 14 days after injury.Among the differentially expressed genes,those most up-regulated showed fold changes of more than 214,while those most down-regulated exhibited fold changes of more than 2-10.Gene sequencing showed that,at all time points after injury,a variety of MMP genes in the “Inhibition of MMPs” pathway were up-regulated,and their inhibitor genes were down-regulated.Expression of key up-and down-regulated genes was verified by quantitative real-time polymerase chain reaction analysis and found to be consistent with transcriptome sequencing.These results suggest that MMP-related genes are strongly involved in the process of peripheral nerve regeneration.
基金Funded by the Special Fund for Research Institutes of the Ministry of Science and Technology of China(No.2013EG115007)the General Program of Natural Science Fund of Guangxi province in China(No.2013GXNSFAA019320)+2 种基金the Plan program of Scientific Research and Technical Development of Guangxi province in China(No.1348008-3)the Program of Scientific Development of China Nonferrous Metal Mining(group)Co,Ltd(No.2013KJJH11)the Plan program of Scientific Research and Technical Development of Guilin in China(Nos.20140104-4 and 20150105-1)
文摘We studied the effects of sintering temperature on FeCuCo based pre-alloyed powder for diamond bits.The FeCuCo composite was fabricated by co-precipitation method.With the addition of tungsten carbide（WC）,sintering under different temperatures was investigated.Mechanical properties of the FeCuCo based matrix were systematically studied.The structure of the composite was evaluated by X-ray diffraction（XRD） and scanning electron microscope（SEM） was used to analyze the surface of the powder and matrix.The suitable sintering temperature was determined through differential scanning calorimeter（DSC）.Micro drilling experiments were performed,and 820 ℃ was identified to be the ideal sintering temperature,at which the matrix shows the best mechanical properties and drilling performance.
基金financially supported by the National Natural Science Foundation of China(Nos.21674120,81630056,21474115)PLA(No.AWS14C003)“Young Thousand Talents Program”
文摘PEG-related adhesives are limited in clinical use because they are easy to swell and cannot support the cell growth. In this study, we produced a series of POSS-modified PEG adhesives with high adhesive strength. Introduction of inorganic hydrophobic POSS units decreased the swelling of the adhesives and enhanced cell adhesion and growth. The in vitro cytotoxicity and in vivo inflammatory response experiments clearly demonstrated that the adhesives were nontoxic and possessed excellent biocompatibility. Compared with the sutured wounds, the adhesive-treated wounds showed an accelerated healing process in wounded skin model of the Bama miniature pig, demonstrating that the POSS-modified PEG adhesive is a promising candidate for wound closure.
基金supported by the National Natural Science Foundation of China,No.81501058the Natural Science Foundation of Jiangsu Province of China,No.BK20150409+1 种基金the Natural Science Foundation of Jiangsu Higher Education Institutions of China,No.15KJB180013,15KJB310014a grant from the Priority Academic Program Development of Jiangsu Higher Education Institutions of China
文摘Wallerian degeneration is a critical biological process that occurs in distal nerve stumps after nerve injury. To systematically investigate molecular changes underlying Wallerian degeneration, we used a rat sciatic nerve transection model to examine microarray analysis outcomes and investigate significantly involved Kyoto Enrichment of Genes and Genomes（KEGG） pathways in injured distal nerve stumps at 0, 0.5, 1, 6, 12, and 24 hours, 4 days, 1, 2, 3, and 4 weeks after peripheral nerve injury. Bioinformatic analysis showed that only one KEGG pathway（cytokine-cytokine receptor interaction） was significantly enriched at an early time point（1 hour post-sciatic nerve transection）. At later time points, the number of enriched KEGG pathways initially increased and then decreased. Three KEGG pathways were studied in further detail： cytokine-cytokine receptor interaction, neuroactive ligand-receptor interaction, and axon guidance. Moreover, temporal expression patterns of representative differentially expressed genes in these KEGG pathways were validated by real time-polymerase chain reaction. Taken together, the above three signaling pathways are important after sciatic nerve injury, and may increase our understanding of the molecular mechanisms underlying Wallerian degeneration.
基金supported by the National Natural Science Foundation of China(Nos.5110311550903065 and 51573146)+3 种基金Fundamental Research Funds for the Central Universities(Nos.XJJ2013075 and cxtd2015003)International Science & Technology Cooperation Program of China(No.2013DFR50470)Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2013JZ003 and 2015JZ009)National Basic Research Program of China 973(No.6132620101)
文摘After annealing the solution cast P（VDF-TrFE） films at elevated temperatures, which were synthesized via a full hydrogenation process from P（VDF-CTFE） with a composition of VDF/TrFE = 80/20（mol%）, a series of P（VDF-TrFE） films were fabricated in present work. The crystalline and ferroelectric phases of the films were carefully characterized and their dielectric, ferroelectric and piezoelectric properties were systematically investigated. The improved crystalline and ferroelectric phases in the films induced by annealing at elevated temperatures are responsible for the significant improved electric properties of the films. The optimized annealing temperature is found to be 130 ℃ and the best performance including the highest dielectric constant of 12.5 at 1 kHz, the largest maximum polarization of 11.21 μC/cm^2 and remnant polarization of 7.22 μC/cm^2, the lowest coercive electric field of 56 MV/m, and the highest piezoelectric coefficient of -25 pC/N is observed.
基金supported by the National Natural Science Foundation of China(Nos.5126301051303073 and 51272096)+2 种基金Natural Science Foundation of Jiangxi Province(No.20142BAB206028)the Science and Technology Landing Plan of Universities in Jiangxi Province(No.KJLD14069)Provincial Project for Postgraduate Innoviation in Jiangxi Science and Technology Normal University(No.YC2014-X27)
文摘Two pairs of amino-acid functionalized poly（3,4-ethylenedioxythiophene）（PEDOT） derivatives, namely, poly（N-（tert-butoxycarbonyl）-L-methionyl（3,4-ethylenedioxythiophene-2＇-yl）methylamide）（L-PEDOT-Boc-Met） and poly（N-（tertbutoxycarbonyl）-D-methionyl（3,4-ethylenedioxythiophene-2＇-yl）methylamide）（D-PEDOT-Boc-Met）; poly（L-methionyl（3,4-ethylenedioxythiophene-2＇-yl）methylamide）（L-PEDOT-Met） and poly（D-methionyl（3,4-ethylenedioxythiophene-2＇-yl）methylamide）（D-PEDOT-Met） were synthesized via chemical oxidative polymerization of corresponding monomers. The structural characterization, spectroscopic properties and thermal stability of these monomers and polymers were systematically explored by FTIR spectra, Raman spectra, XRD spectra, UV-Vis spectra and thermogravimetric analysis. As chiral electrode materials, these polymers were employed to successfully recognize 3,4-dihydroxyphenylalanine（DOPA） enantiomers by cyclic voltammetry（CV） in sulphuric acid solution. The measurement results reveal that the tendency was hetero-chiral interaction between L-PEDOT-Met/PVA/GCE and D-DOPA, D-PEDOT-Met/PVA/GCE and L-DOPA, respectively. Also, the mechanism of chiral discrimination was discussed. All the results implied that the combination of electrochemical molecular recognition technology and chiral PEDOT materials can be a promising approach for chiral recognition and may open new opportunities for facile, biocompatible, sensitive and robust chiral assays in biochemical applications.
基金Item Sponsored by National Basic Research Program of China(2015CB655100)National Natural Science Foundation of China(51308111+4 种基金51278098)Postdoctoral Science Foundation of China(2013M531249)Industry-University-Research Cooperative Innovation Fund of Jiangsu Province of China(BY2013091)Postdoctoral Science Foundation of Jiangsu Province of China(1202008C)Applied Research Foundation of Nantong City of Jiangsu Province of China(BK2013001)
文摘A new low-cost corrosion-resistant rebar（HRB400R）was designed and fabricated by Cr micro-alloying.The HRB400 Rrebar had uniform distribution of Cr element in ferrite grains.The corrosion behavior of the rebar in the neutral Cl^--containing environment was studied systematically,and the improved corrosion resistance of the HRB400 Rrebar was revealed.According to the corrosion-morphology observation and electrochemical monitoring during the constant immersion corrosion in the 3.5mass% NaCl solution,the HRB400 Rrebar presented alleviated corrosion damage,nobler Ecorr,lower Icorr,and larger Rtvalues,and these phenomena were more remarkable in the initial corrosion period.The elevated electrode potential of the rebar,caused by the solid-solution of Cr micro-alloying in the ferrite grains,was the key to the corrosion-resistance improvement.The HRB400 Rrebar also presented much lower mass-loss rate in the salt spray corrosion test.Besides the elevated corrosion resistance of the matrix,the doping and enrichment of Cr element in the rust layer was another factor for the higher corrosion resistance,which retarded the penetration of aggressive medium through the rust layer.
基金supported by the National Natural Science Foun-dations of China(Grant Nos.11402230,11332009 and 11272284)
文摘Droplet migration in plane Poiseuille flow is numerically investigated with a dissipative particle dynamics method.The single droplet deformation in the channel flow is first studied to verify the current method and the physical model.The effect of the viscosity ratio between the droplet and the solvent and the effect of the confinement are systematically investigated.The droplet is in an off-centerline equilibrium position with a specific selection of the parameters.A large viscosity ratio makes the droplet locate in a near-wall equilibrium position,and a large capillary number makes the droplet migrate to the near-centerline region of the channel.For the droplet migration at the same Capillary number,there is a critical width of the channel,which is less than twice of the droplet diameter,and the droplet will only migrate to the channel centerline if the width is less than this critical value.
基金financially supported by the National Natural Science Foundation of China(Nos.21574076,U1510121,21501113,61504076 and 21407100)the Science Foundation of Shanxi province(Nos.2014011016-1 and 2015021129)the Program for the Top Young and Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.020352901014)
文摘Flexible electrochemical capacitors（ECs） are vitally important as the emerging flexible electronics.We have prepared polypyrrole doped with counter ion of Cl-on carbon fibers（PPy-Cl/CFs） via the simple electrochemical deposition method.The flexible ECs based on PPy-Cl/CFs electrodes have been assembled by using H_3PO_4/poly（vinyl alcohol）（PVA）,H_2SO_4/PVA,LiClO_4/PVA,KCl/PVA and Li Cl/PVA as gel electrolytes.The capacitive properties of ECs have been systematically evaluated with electrochemical methods.The results show that the cells with H_3PO_4/PVA electrolyte exhibit good cyclic stability（91.5% retention after 15000 cycles） although PPy-Cl/CFs has moderate specific capacitance in H_3PO_4/PVA（41.6 m F·cm^-1 or 52.0 F·cm^-3）.However,the ECs in other electrolytes have poor cyclic stability.Further electrochemical analysis reveals that the doping/dedoping processes of PPy-Cl/CFs are different in the five electrolytes,and X-ray photoelectron spectra demonstrate that the ratios of counter anions in PPy＇s oxidized states to those in reduced states are obviously different when PPy-Cl/CFs are kept in reduced or oxidized states in the five electrolytes.The results also illustrate why the capacitors using H_3PO_4/PVA as electrolyte exhibit good cyclic stability.Furthermore,a light emitting diode（LED） with a threshold voltage of 2.5 V can be lighted by three ECs connected in series.
基金Project supported by the National Natural Science Foundation of China(Grant No.U1632273)the Chinese Universities Scientific Fund(Grant No.CX3430000001)
文摘Luminescent solar concentrators（LSC） can reduce the area of solar cells by collecting light from a large area and concentrating the captured light onto relatively small area photovoltaic（PV） cells, and thereby reducing the cost of PV electricity generation. LSCs with bottom-facing cells（BMP-LSC） can collect both direct light and indirect light, so further improving the efficiency of the PV cells. However, it is hard to analyze the effect of each parameter by experiment because there are too many parameters involved in the BMP-LSC. In this paper, all the physical processes of the light transmission and collection in the BMP-LSC were analyzed. A three-dimensional Monte Carlo ray tracing program was developed to study the transmission of photons in the LSC. A larger-size LSC was simulated, and the effects of dye concentration, the LSC thickness, the cell area, and the cell distance were systematically analyzed.
基金Project supported by the National Natural Science Foundation of China(51562025)Graduate Student Innovation Special Funds(YC2016-S085) of Jiangxi Province
文摘Eu^3＋/Dy^3＋ single-doped and co-doped 6SrO-3Al2O3-91SiO2 and 12SrO-6Al2O3-82SiO2 glass and glass-ceramics were synthesized successfully by a sol-gel method. The prepared samples were characterized by the X-ray diffraction, high-resolution transmission electron microscopy, photoluminescent spectra and X-ray photoelectron spectroscopy. The effect of annealing temperature, doped ions and matrix component on the structure and the photoluminescent characteristics was systematically studied. The higher temperature was helpful to form nanocrystals and the amount of SrO and Al2O3 could better disperse the rare earth ions in matrix at suitable temperature, and both of them could improve the luminescent intensity. Meanwhile, the doped ions could change the luminescent color by single, codoped and energy transfer. The Sr2SiO4 nanocrystals were observed in silicates glasses and became larger with the increase of the annealing temperature and the luminous efficiency of rare-earth（RE） ions could be enhanced when the samples changed from glass state to glass-ceramic state. The results indicated that the photoluminescent properties could be changed through controlling the doped ions, annealing temperature and matrix component.
基金supported by the National Natural Science Foundation of China(Nos.20804027 and 21274106)
文摘The influence of sodium dodecyl sulfate（SDS） on the cloud point temperature（Tcp） of the aqueous solution of thermoresponsive hyperbranched polyethylenimine derivative HPEI-IBAm was studied systematically. When pH was below 8.5, HPEI-IBAm was positively-charged. Initially, the Tcp of HPEI-IBAm decreased significantly, followed by an obvious increase with the increase of SDS concentration. The lower the pH was, the higher the SDS concentration was required to achieve the minimum Tcp. When pH was above 8.5, HPEI-IBAm was neutral and raising the SDS concentration led to the gradual increase of Tcp. Compared to linear poly（N-isopropyl acrylamide）（PNIPAm）, the Tcp of the current hyperbranched HPEI-IBAm was more sensitive to SDS. The thermoresponsive HPEI-IBAm/SDS complex was used as host to accommodate the non-polar pyrene in water. The lowest SDS concentration for effectively enhancing the solubility of pyrene in water was around 6.4 mmol·L^-1. When HPEI-IBAm was present, the SDS concentration threshhold was decreased to about 0.31 mmol·L^-1. Fluorescence technique with pyrene as the hydrophobic probe demonstrated that the SDS concentration of 7.2 mmol·L^-1 was required to form the hydrophobic domain to accommodate pyrene guests without HPEI-IBAm, while only 0.2 mmol·L^-1 of SDS was required in the presence of HPEI-IBAm.
基金financially supported by the National Natural Science Foundation of China(Nos.21227802,21303216 and21473217)
文摘Sum frequency generation spectroscopy（SFG） has been widely used to study the interfacial chemistry of aqueous salt solutions of biological or environmental importance. Most of the SFG data analysis used the same bulk refractive index for different salt concentrations despite of the variations of the refractive indices. Here we systematically investigate the influence of the refractive index on the SFG intensities at various experimental conditions. It is discovered that the SFG intensities are the most sensitive to the refractive index at solid/liquid interfaces nearby the total internal reflection geometries. At air/liquid interfaces, the effect of the refractive indices is also nonegligible. Consequently some important SFG results, such as the response of water structures to the ionic strength at the SiO2/aqueous interfaces, are necessary to be reevaluated. These conclusions on the effect of the small variations of the refractive index are generally useful for the common practice of SFG data analysis.
基金Supported by National Natural Science Foundation of China(11175240,11205234,11322550)Program for Changjiang Scholars and Innovative Research Team in University(IRT1280)
文摘Due to high reflectivity and high resolution of X-ray pulses, diamond is one of the most popular Bragg crystals serving as the reflecting mirror and mono-chromator in the next generation of free electron lasers（FELs）.The energy deposition of X-rays will result in thermal heating, and thus lattice expansion of the diamond crystal,which may degrade the performance of X-ray FELs. In this paper, the thermal loading effect of diamond crystal for X-ray FEL oscillators has been systematically studied by combined simulation with Geant4 and ANSYS, and its dependence on the environmental temperature, crystal size, X-ray pulse repetition rate and pulse energy are presented. Our results show that taking the thermal loading effects into account, X-ray FEL oscillators are still robust and promising with an optimized design.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11575205,11475197,11675188,and 11475193)
文摘Doppler broadening and coincidence Doppler broadening of annihilation radiation experiments have been performed in three kinds of polyethylene glycol（PEG） membrane formed with different average molecular weight using the tunable monoenergy slow positron probe as a function of implantion energy. The obtained positron annihilation parameters are interpreted from two aspects： surface effect and differences in micro-structure or chemical environment of positron annihilation. The experimental results show that the regulation of densification of PEG molecular packing and distribution uniformity from the near surface layer to the bulk region in the film forming process can be well realized by changing its molecular weight. Combining a variable monoenergetic slow positron beam and these two positron annihilation spectroscopy methods is a powerful tool to study positron annihilation characteristics and for polymeric thin-film fine structure analysis.
文摘The polymorphisms of toll-like receptor（TLR） have been hypothesized to affect the tuberculosis susceptibility. However, the direct evidence remains controversial. Here we performed a comprehensive meta-analysis to summarize the associations between TLR polymorphisms and tuberculosis susceptibility. We systematically searched the Pub Med, Embase, Cochrane library, and Chinese National Knowledge Infrastructure up to April 25, 2014. Case-control studies investigating TLR polymorphisms and tuberculosis susceptibility were included in the meta-analysis. Pooled odds ratios and corresponding 95% confidence intervals were calculated for cases and controls. Stata 11.0 and Review Manager 5.1 were adopted to conduct statistical analysis. We included 29 studies, involving 17 804 individuals. The results revealed an obvious increase of tuberculosis risk in TLR2 2258 AA, and decreased risk in TLR6 745 TT and TLR8 rs3761624 GA genotypes. Meanwhile, different genetic models were performed. TLR8 rs3764879 C, TLR8 rs3761624 A and TLR8 rs3764880 A alleles were associated with high susceptibility, while TLR6 745 T and TLR8 rs3788935 C alleles were protective. Other polymorphisms, including TLR9 1486C/T, did not show significant associations with tuberculosis infection. Finally, subgroup analysis in TLR8 rs3764880 according to gender found a slight elevated effect of A allele in males. The meta-analysis suggests significant associations between several TLR polymorphisms and tuberculosis, including TLR2 2258G/A, TLR6 745C/T, TLR8 rs3761624, TLR8 rs3764879, TLR8 rs3761624 and TLR8 rs3764880. This study serves as the framework for additional studies to determine further the role of TLRs in tuberculosis infection.
