Capacitive power transfer(CPT)technology is a newly emerging research focus for EV charging applications.Due to the absence of eddy current loss and light weight of the capacitive coupling metal plates,CPT technology ...Capacitive power transfer(CPT)technology is a newly emerging research focus for EV charging applications.Due to the absence of eddy current loss and light weight of the capacitive coupling metal plates,CPT technology is considered to be a promising alternative to the inductive power transfer(IPT)technology.In this paper,the recent designs of large-gap CPT systems designed for EV charging applications are summarized.And a graphical method based on Smith chart is proposed to analyze the characteristics of the compensation designs.With the design objectives graphically represented,the Smith chart can be used to visually analyze the performance of a compensation design,which could be helpful in multi-objectives design of the CPT system.The graphic features of three major design objectives on the Smith chart are investigated.Several guidelines of a good compensation design are concluded.展开更多
Tin (Sn) metal foil is a promising anode for next-generation high-energy–density lithium-ion batteries (LIBs) due to its high capacity and easy processibility. However, the pristine Sn foil anode suffers nonuniform a...Tin (Sn) metal foil is a promising anode for next-generation high-energy–density lithium-ion batteries (LIBs) due to its high capacity and easy processibility. However, the pristine Sn foil anode suffers nonuniform alloying/dealloying reaction with lithium (Li) and huge volume variation, leading to electrode pulverization and inferior electrochemical performance. Herein, we proposed that reduced grain size and elaborate porosity design of Sn foil can circumvent the nonuniform alloy reaction and buffer the volume change during the lithiation/delithiation cycling. Experimentally, we designed a three-dimensional interconnected porous Sn (3DIP-Sn) foil by a facile chemical alloying/dealloying approach, which showed improved electrochemical performance. The enhanced structure stability of the as-fabricated 3DIP-Sn foil was verified by chemo-mechanical simulations and experimental investigation. As expected, the 3DIP-Sn foil anode revealed a long cycle lifespan of 4400 h at 0.5 mA cm^(−2) and 1 mAh cm^(−2) in Sn||Li half cells. A 3DIP-Sn||LiFePO_(4) full cell with LiFePO_(4) loading of 7.1 mg cm^(−2) exhibited stable cycling for 500 cycles with 80% capacity retention at 70 mA g^(−1). Pairing with high-loading commercial LiNi0.6Co0.2Mn0.2O_(2) (NCM622, 18.4 mg cm^(−2)) cathode, a 3DIP-Sn||NCM622 full cell delivered a high reversible capacity of 3.2 mAh cm^(−2). These results demonstrated the important role of regulating the uniform alloying/dealloying reaction and circumventing the localized strain/stress in improving the electrochemical performance of Sn foil anodes for advanced LIBs.展开更多
Objective:To investigate the relationship of iodine nutritional status with thyroid function in pregnant women in Baotou,and provide a scientific basis for the guide of reasonable iodine supplementation.Methods:By use...Objective:To investigate the relationship of iodine nutritional status with thyroid function in pregnant women in Baotou,and provide a scientific basis for the guide of reasonable iodine supplementation.Methods:By use of As-Ce catalysis spectrophotometry,the urinary iodine concentration was determined in 90 women during different periods of pregnancy admitted to Baogang Hospital of Inner Mongolia from January 2017 to December 2017.The determination of thyroid function and the autoantibody level was carried out by electro-chemiluminescence immunoassay(ECLIA).Results:In the early trimester of pregnancy,pregnant women with iodine deficiency,iodine sufficiency and iodine excess accounted for 36.67%,40.00%and 23.33%respectively;in the middle trimester of pregnancy,they accounted for 66.67%,26.67%and 6.66%respectively;they made up 40.00%,40.00%and 20.00%respectively in the late trimester of pregnancy.The rate of iodine deficiency in women in the middle trimester of pregnancy was significantly higher than that in women in the early and the late trimesters of pregnancy respectively,and the difference was statistically significant(p<0.05).The rate of iodine deficiency in pregnant women was positively correlated to the positivity of thyroid peroxidase antibody.Moreover,it had no relationship with the positivity of thyroglobulin antibody.No matter in the pregnant women with iodine deficiency or with iodine excess,the abnormality rate of thyroid function and autoantibodies was significantly higher than that in the pregnant women with iodine sufficiency.The difference was statistically significant(p<0.05).Conclusions:The iodine deficiency in the women in the middle trimester of pregnancy is more severe than that in the women in the early and the late trimesters of pregnancy.Iodine deficiency during pregnancy is positively correlated with the positivity of thyroid peroxidase antibody.Pregnant women with iodine deficiency and iodine excess show a higher abnormality rate of thyroid function and autoantibodies.It is recommended to advocate health education on iodine nutrition to pregnant women,and conduct the dynamic monitoring of urinary iodine concentration and the screening of thyroid function and autoantibodies during pregnancy.展开更多
Herein,we report a microwave-assisted acid-induced post-treatment method for the formation of linker vacancies within Zr-based metal organic frameworks(Zr-MOFs).The number of linker vacancies can be easily regulated w...Herein,we report a microwave-assisted acid-induced post-treatment method for the formation of linker vacancies within Zr-based metal organic frameworks(Zr-MOFs).The number of linker vacancies can be easily regulated with this method by changing the concentration of the HCl solution and the duration of microwave irradiation.The optimized defective UiO-66 showed higher linker defects with a higher specific surface area and thermal stability.The results of the catalytic cyclization of citronella showed that the Zr-MOFs with more defects exhibited enhanced catalytic performance.This work may provide a new method for the creation of defective MOFs with high activity and stability.展开更多
Oxygen evolution reaction(OER)is a bottleneck process for many electrochemical devices due to the sluggish kinetics,for which advanced electrocatalysts should be carefully designed.Nickle-based materials have been ext...Oxygen evolution reaction(OER)is a bottleneck process for many electrochemical devices due to the sluggish kinetics,for which advanced electrocatalysts should be carefully designed.Nickle-based materials have been extensively studied to catalyze OER.However,their performances are still below the expectation and the active sites are often controversial.Herein,we have successfully modulated the electronic and surface properties of layeredβ-Ni(OH)2 by the interlayer ligand engineering,aiming to design novel efficient electrocatalysts and unveil the catalysis mechanism.By one-step solvothermal reaction,alkoxyl substitutedβ-Ni(OH)2 with variable interlayer distances is obtained,and the ethoxyl substituted one(NiEt)shows great potential for efficient OER.With the assistance of powder X-ray diffraction and crystalline structure computational simulation,the formula of alkoxyl substitutedβ-Ni(OH)2 are determined.Operando X-ray absorption spectroscopy studies combined with ex-situ analyses revealed that the critical active species of NiEt is formed via hydroxylation and subsequent de-protonation,with high valent Niδ+(3<δ≤3.66).The corresponding catalytic reaction pathway and mechanism are proposed.展开更多
Scalar optical hopfions weaved by nested equiphase lines in the shape of a toroidal vortex are theoretically designed and experimentally demonstrated.This category of hopfions manifesting as a spatiotemporally structu...Scalar optical hopfions weaved by nested equiphase lines in the shape of a toroidal vortex are theoretically designed and experimentally demonstrated.This category of hopfions manifesting as a spatiotemporally structured pulse propagating in space-time may enable encoding and transferring optical topological information in an additional(temporal)dimension.展开更多
Flaxseed cake contains cyanogenic glucosides, which can be metabolized into hydrocyanic acid in an animal's body, leading to asphyxia poisoning in cells. Beta-glucosidase is highly efficient in degrading cyanogeni...Flaxseed cake contains cyanogenic glucosides, which can be metabolized into hydrocyanic acid in an animal's body, leading to asphyxia poisoning in cells. Beta-glucosidase is highly efficient in degrading cyanogenic glucosides. The Cattle may have b-glucosidase-producing strains in the intestinal tract after eating small amounts of flaxseed cake for a long time. This study aimed to isolate of a strain from cow dung that produces b-glucosidase with high activity and can significantly reduce the amount of cyanogenic glucosides. We used cow dung as the microflora source and an esculin agar as the selective medium. After screening with 0.05% esculin and 0.01% ferric citrate, we isolated 5 strains producing high amounts of b-glucosidase. In vitro flaxseed cake fermentation was fermented by these 5 strains, in which the strain M-2 exerted the best effect(P < 0.05). The strain M-2 was identified as Lichtheimia ramosa and used as the fermentation strain to optimize the fermentation parameters by a single factor analysis and orthogonal experimental design. The optimum condition was as follows: inoculum size3%, water content 60%, time 144 h, and temperature 32℃. Under this condition, the removal rate of cyanogenic glucosides reached 89%, and crude protein increment reached 44%. These results provided a theoretical basis for the removal of cyanogenic glucosides in flaxseed and the comprehensive utilization of flaxseed cake.展开更多
1.Introduction Nearβtitanium alloys have been considered as a potential material to fabricate high-strength fasteners in aerospace field owing to their high specific strength,good crack and fatigue resistance[1,2].It...1.Introduction Nearβtitanium alloys have been considered as a potential material to fabricate high-strength fasteners in aerospace field owing to their high specific strength,good crack and fatigue resistance[1,2].It is well known that the processing technology determines the microstructure,and the microstructure eventually correlates with the performance of alloys.展开更多
First-principles methods based on density functional theory(DFT)are nowadays routinely applied to calculate the elastic constants of materials at temperature of 0 K.Nevertheless,the first-principles calculations of el...First-principles methods based on density functional theory(DFT)are nowadays routinely applied to calculate the elastic constants of materials at temperature of 0 K.Nevertheless,the first-principles calculations of elastic constants at finite temperature are not straightforward.In the present work,the feasibility of the ab initio molecular dynamic(AIMD)method in calculations of the temperature dependent elastic constants of relatively"soft"metals,taking face centered cubic(FCC)aluminum(Al)as example,is explored.The AIMD calculations are performed with carefully selected strain tensors and strain magnitude.In parallel with the AIMD calculations,first-principles calculations with the quasiharmonic approximation(QHA)are performed as well.We show that all three independent elastic constant components(C11,C12 and C44)of Al from both the AIMD and QHA calculations decrease with increasing temperature T,in good agreement with those from experimental measurements.Our work allows us to quantify the individual contributions of the volume expansion,lattice vibration(excluding those contributed to the volume expansion),and electronic temperature effects to the temperature induced variation of the elastic constants.For Al with stable FCC crystal structure,the volume expansion effect contributes the major part(about 75%~80%)in the temperature induced variation of the elastic constants.The contribution of the lattice vibration is minor(about 20%~25%)while the electronic temperature effect is negligible.Although the elastic constants soften with increasing temperature,FCC Al satisfies the Born elastic stability criteria with temperature up to the experimental melting point.展开更多
Flexible ferroelectric memories,endowing with high data storage density,provide a chance for the nextgeneration wearable electronics.Here,flexible inorganic Mn-doped BiFeO_(3) thin films were directly integrated on fl...Flexible ferroelectric memories,endowing with high data storage density,provide a chance for the nextgeneration wearable electronics.Here,flexible inorganic Mn-doped BiFeO_(3) thin films were directly integrated on fluorophlogopite mica(F-Mica)substrates by an easy and low-cost all solution chemical solution deposition(AS-CSD)route.The integration of LaNiO_(3) buffer layer can improve the film surface density and uniformity.The flexible characteristic can be achieved by reducing the thickness of F-Mica substrates for the ferroelectric thin films.In contrast to BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/Si thin film deposited on rigid substrates(Si),the BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/F-mica fabricated on F-Mica show better ferroelectric performances due to the improved crystal growth and less defects.More importantly,the obtained BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/F-mica ferroelectric thin films still show large remnant polarization of Pr ~64 μC/cm^(2)(deterioration of ~7.2%),good antifatigue properties up to 1.2×10^(8) cycles and outstanding retention behaviors for 1.6×10^(4) s after continuous bending.This work will provide a feasible route to fabricate flexible inorganic ferroelectric thin films through low-cost solution method and show attractive comprehensive performances in next-generation wearable smart devices.展开更多
基金This work was supported by National Natural Science Foundation of China(51507168)International Science&Technology Cooperation Program of China(2016YFE0102200)Beijing information science and technology university 2017'training plan"project.
文摘Capacitive power transfer(CPT)technology is a newly emerging research focus for EV charging applications.Due to the absence of eddy current loss and light weight of the capacitive coupling metal plates,CPT technology is considered to be a promising alternative to the inductive power transfer(IPT)technology.In this paper,the recent designs of large-gap CPT systems designed for EV charging applications are summarized.And a graphical method based on Smith chart is proposed to analyze the characteristics of the compensation designs.With the design objectives graphically represented,the Smith chart can be used to visually analyze the performance of a compensation design,which could be helpful in multi-objectives design of the CPT system.The graphic features of three major design objectives on the Smith chart are investigated.Several guidelines of a good compensation design are concluded.
基金This work is financially supported by the National Natural Science Foundation of China(Grant Nos.52072137,51802105).
文摘Tin (Sn) metal foil is a promising anode for next-generation high-energy–density lithium-ion batteries (LIBs) due to its high capacity and easy processibility. However, the pristine Sn foil anode suffers nonuniform alloying/dealloying reaction with lithium (Li) and huge volume variation, leading to electrode pulverization and inferior electrochemical performance. Herein, we proposed that reduced grain size and elaborate porosity design of Sn foil can circumvent the nonuniform alloy reaction and buffer the volume change during the lithiation/delithiation cycling. Experimentally, we designed a three-dimensional interconnected porous Sn (3DIP-Sn) foil by a facile chemical alloying/dealloying approach, which showed improved electrochemical performance. The enhanced structure stability of the as-fabricated 3DIP-Sn foil was verified by chemo-mechanical simulations and experimental investigation. As expected, the 3DIP-Sn foil anode revealed a long cycle lifespan of 4400 h at 0.5 mA cm^(−2) and 1 mAh cm^(−2) in Sn||Li half cells. A 3DIP-Sn||LiFePO_(4) full cell with LiFePO_(4) loading of 7.1 mg cm^(−2) exhibited stable cycling for 500 cycles with 80% capacity retention at 70 mA g^(−1). Pairing with high-loading commercial LiNi0.6Co0.2Mn0.2O_(2) (NCM622, 18.4 mg cm^(−2)) cathode, a 3DIP-Sn||NCM622 full cell delivered a high reversible capacity of 3.2 mAh cm^(−2). These results demonstrated the important role of regulating the uniform alloying/dealloying reaction and circumventing the localized strain/stress in improving the electrochemical performance of Sn foil anodes for advanced LIBs.
文摘Objective:To investigate the relationship of iodine nutritional status with thyroid function in pregnant women in Baotou,and provide a scientific basis for the guide of reasonable iodine supplementation.Methods:By use of As-Ce catalysis spectrophotometry,the urinary iodine concentration was determined in 90 women during different periods of pregnancy admitted to Baogang Hospital of Inner Mongolia from January 2017 to December 2017.The determination of thyroid function and the autoantibody level was carried out by electro-chemiluminescence immunoassay(ECLIA).Results:In the early trimester of pregnancy,pregnant women with iodine deficiency,iodine sufficiency and iodine excess accounted for 36.67%,40.00%and 23.33%respectively;in the middle trimester of pregnancy,they accounted for 66.67%,26.67%and 6.66%respectively;they made up 40.00%,40.00%and 20.00%respectively in the late trimester of pregnancy.The rate of iodine deficiency in women in the middle trimester of pregnancy was significantly higher than that in women in the early and the late trimesters of pregnancy respectively,and the difference was statistically significant(p<0.05).The rate of iodine deficiency in pregnant women was positively correlated to the positivity of thyroid peroxidase antibody.Moreover,it had no relationship with the positivity of thyroglobulin antibody.No matter in the pregnant women with iodine deficiency or with iodine excess,the abnormality rate of thyroid function and autoantibodies was significantly higher than that in the pregnant women with iodine sufficiency.The difference was statistically significant(p<0.05).Conclusions:The iodine deficiency in the women in the middle trimester of pregnancy is more severe than that in the women in the early and the late trimesters of pregnancy.Iodine deficiency during pregnancy is positively correlated with the positivity of thyroid peroxidase antibody.Pregnant women with iodine deficiency and iodine excess show a higher abnormality rate of thyroid function and autoantibodies.It is recommended to advocate health education on iodine nutrition to pregnant women,and conduct the dynamic monitoring of urinary iodine concentration and the screening of thyroid function and autoantibodies during pregnancy.
基金supported by the National Natural Science Foundation of China (No.21573063)the Hunan Provincial Natural Science Foundation of Youth Fund (No.2020JJ3002)+1 种基金Open Fund from Hunan Provincial Key Laboratory of Advanced Materials for New Energy Storage and Conversion (No.2018TP1037201902)the Training Program of Hunan University of Youth Fund。
文摘Herein,we report a microwave-assisted acid-induced post-treatment method for the formation of linker vacancies within Zr-based metal organic frameworks(Zr-MOFs).The number of linker vacancies can be easily regulated with this method by changing the concentration of the HCl solution and the duration of microwave irradiation.The optimized defective UiO-66 showed higher linker defects with a higher specific surface area and thermal stability.The results of the catalytic cyclization of citronella showed that the Zr-MOFs with more defects exhibited enhanced catalytic performance.This work may provide a new method for the creation of defective MOFs with high activity and stability.
基金This work was supported by the Fundamental Research Funds for the Central Universities(531107051102)the National Natural Science Foundation of China(51402100,21825201,21573066,21805080,21902047)the Provincial Natural Science Foundation of Hunan(2016TP1009,2020JJ5045).
文摘Oxygen evolution reaction(OER)is a bottleneck process for many electrochemical devices due to the sluggish kinetics,for which advanced electrocatalysts should be carefully designed.Nickle-based materials have been extensively studied to catalyze OER.However,their performances are still below the expectation and the active sites are often controversial.Herein,we have successfully modulated the electronic and surface properties of layeredβ-Ni(OH)2 by the interlayer ligand engineering,aiming to design novel efficient electrocatalysts and unveil the catalysis mechanism.By one-step solvothermal reaction,alkoxyl substitutedβ-Ni(OH)2 with variable interlayer distances is obtained,and the ethoxyl substituted one(NiEt)shows great potential for efficient OER.With the assistance of powder X-ray diffraction and crystalline structure computational simulation,the formula of alkoxyl substitutedβ-Ni(OH)2 are determined.Operando X-ray absorption spectroscopy studies combined with ex-situ analyses revealed that the critical active species of NiEt is formed via hydroxylation and subsequent de-protonation,with high valent Niδ+(3<δ≤3.66).The corresponding catalytic reaction pathway and mechanism are proposed.
文摘Scalar optical hopfions weaved by nested equiphase lines in the shape of a toroidal vortex are theoretically designed and experimentally demonstrated.This category of hopfions manifesting as a spatiotemporally structured pulse propagating in space-time may enable encoding and transferring optical topological information in an additional(temporal)dimension.
基金supported by Jiangsu Science and Technology Major Project (BA2016036)Lanzhou Science and Technology Funds (2015-3-81)Gansu Science and Technology Major Project (17ZD2FA009)
文摘Flaxseed cake contains cyanogenic glucosides, which can be metabolized into hydrocyanic acid in an animal's body, leading to asphyxia poisoning in cells. Beta-glucosidase is highly efficient in degrading cyanogenic glucosides. The Cattle may have b-glucosidase-producing strains in the intestinal tract after eating small amounts of flaxseed cake for a long time. This study aimed to isolate of a strain from cow dung that produces b-glucosidase with high activity and can significantly reduce the amount of cyanogenic glucosides. We used cow dung as the microflora source and an esculin agar as the selective medium. After screening with 0.05% esculin and 0.01% ferric citrate, we isolated 5 strains producing high amounts of b-glucosidase. In vitro flaxseed cake fermentation was fermented by these 5 strains, in which the strain M-2 exerted the best effect(P < 0.05). The strain M-2 was identified as Lichtheimia ramosa and used as the fermentation strain to optimize the fermentation parameters by a single factor analysis and orthogonal experimental design. The optimum condition was as follows: inoculum size3%, water content 60%, time 144 h, and temperature 32℃. Under this condition, the removal rate of cyanogenic glucosides reached 89%, and crude protein increment reached 44%. These results provided a theoretical basis for the removal of cyanogenic glucosides in flaxseed and the comprehensive utilization of flaxseed cake.
基金the Science and Technology Major Project of Shanxi Province(Nos.20191102008 and 20181101014)the Applied Basic Research Foundation of Shanxi Province(No.201901D211255)+1 种基金Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(Nos.2020L0304 and 2019L0526)the Natural Science Research Project of NUC(Nos.XJJ201916 and XJJ201909)for the financial support to this work。
文摘1.Introduction Nearβtitanium alloys have been considered as a potential material to fabricate high-strength fasteners in aerospace field owing to their high specific strength,good crack and fatigue resistance[1,2].It is well known that the processing technology determines the microstructure,and the microstructure eventually correlates with the performance of alloys.
基金the National Key Research and Development Program of China(No.2016YFB0701301)the National Nature Science Foundation of China(No.91860107)the National Key Basic Research Program(No.2014CB644001)。
文摘First-principles methods based on density functional theory(DFT)are nowadays routinely applied to calculate the elastic constants of materials at temperature of 0 K.Nevertheless,the first-principles calculations of elastic constants at finite temperature are not straightforward.In the present work,the feasibility of the ab initio molecular dynamic(AIMD)method in calculations of the temperature dependent elastic constants of relatively"soft"metals,taking face centered cubic(FCC)aluminum(Al)as example,is explored.The AIMD calculations are performed with carefully selected strain tensors and strain magnitude.In parallel with the AIMD calculations,first-principles calculations with the quasiharmonic approximation(QHA)are performed as well.We show that all three independent elastic constant components(C11,C12 and C44)of Al from both the AIMD and QHA calculations decrease with increasing temperature T,in good agreement with those from experimental measurements.Our work allows us to quantify the individual contributions of the volume expansion,lattice vibration(excluding those contributed to the volume expansion),and electronic temperature effects to the temperature induced variation of the elastic constants.For Al with stable FCC crystal structure,the volume expansion effect contributes the major part(about 75%~80%)in the temperature induced variation of the elastic constants.The contribution of the lattice vibration is minor(about 20%~25%)while the electronic temperature effect is negligible.Although the elastic constants soften with increasing temperature,FCC Al satisfies the Born elastic stability criteria with temperature up to the experimental melting point.
基金supported by the National Key Basic Research program(Grant No.2014CB931704)the Joint Funds of the National Natural Science Foundation of China and the Chinese Academy of Sciences Large-Scale Scientific Facility(Grant No.U1432137).
文摘Flexible ferroelectric memories,endowing with high data storage density,provide a chance for the nextgeneration wearable electronics.Here,flexible inorganic Mn-doped BiFeO_(3) thin films were directly integrated on fluorophlogopite mica(F-Mica)substrates by an easy and low-cost all solution chemical solution deposition(AS-CSD)route.The integration of LaNiO_(3) buffer layer can improve the film surface density and uniformity.The flexible characteristic can be achieved by reducing the thickness of F-Mica substrates for the ferroelectric thin films.In contrast to BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/Si thin film deposited on rigid substrates(Si),the BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/F-mica fabricated on F-Mica show better ferroelectric performances due to the improved crystal growth and less defects.More importantly,the obtained BiFe_(0.93)Mn_(0.07)O_(3)/LaNiO_(3)/F-mica ferroelectric thin films still show large remnant polarization of Pr ~64 μC/cm^(2)(deterioration of ~7.2%),good antifatigue properties up to 1.2×10^(8) cycles and outstanding retention behaviors for 1.6×10^(4) s after continuous bending.This work will provide a feasible route to fabricate flexible inorganic ferroelectric thin films through low-cost solution method and show attractive comprehensive performances in next-generation wearable smart devices.
