With the advantages of abundant resources,high specific capacity,and relatively stable cycling performance,silicon suboxides(SiO_(x) ,x<2)have been recently suggested as promising anodes for next-generation lithium...With the advantages of abundant resources,high specific capacity,and relatively stable cycling performance,silicon suboxides(SiO_(x) ,x<2)have been recently suggested as promising anodes for next-generation lithium-ion batteries(LIBs).SiO_(x) exhibits superior storage capability because of the presence of silicon and smaller volume change upon charge/discharge than Si owing to the buffering effect of the initial lithiation products of inert lithium oxide and lithium silicates,enabling a stable cycle life of electrodes.However,significant improvements such as overcoming issues related to volume changes in cycling and initial irreversible capacity loss and enhancing the ionic and electronic charge transport in poorly conducting SiO_(x) electrodes,are still needed to achieve the satisfactory performance required for commercial applications.This review summarizes recent progress on the cycling performance and initial coulombic efficiency of SiO_(x) .Advances in the design of particle morphology and composite composition,prelithiation and prereduction methods,and usage of electrolyte additives and optimized electrode binders are discussed.Perspectives on the promising research directions that might lead to further improvement of the electrochemical properties of SiO_(x) -based anodes are noted.This paper can serve as a basis for the research and development of high-energy-density LIBs.展开更多
Thyroid cancer (TC) is the most common endocrine system cancer, of note, the overall survival of TC in China is suboptimal when comparing with the developed countries such as US (84.3%vs.98.3%), posing a great challen...Thyroid cancer (TC) is the most common endocrine system cancer, of note, the overall survival of TC in China is suboptimal when comparing with the developed countries such as US (84.3%vs.98.3%), posing a great challenge among professionals involved in this field.Standardization of its diagnosis and treatment not only provides the basis for all the care givers to promote the entire level of TC management, but also is helpful in shortening the distance between China and other developed countries. A multidisciplinary team (MDT)should be involved in the comprehensive clinical management of TC, particularly for those advanced or refractory TC, which needs cooperation among members from ultrasonography, radiology, pathology, surgery.展开更多
Clinical engineering(CE) has evolved rapidly over the last 25 years in China. Among the 34 provincial-level administrative units within China, the Zhejiang Province is one of the most advanced in terms of healthcare t...Clinical engineering(CE) has evolved rapidly over the last 25 years in China. Among the 34 provincial-level administrative units within China, the Zhejiang Province is one of the most advanced in terms of healthcare technology maintenance and management. In order to determine Zhejiang's current stage of development and opportunities for further improvement, a comparison of the performance of its CE departments was made against hospitals in the USA. Data were collected from 21 Zhejiang hospitals and compared to those from 270 acute-care hospitals in USA collected by Truven Health Analytics. The benchmarking comparison was made in three categories: operational, financial, and productivity. Within the operational category, the following metrics were compared: equipment inventory size/operating beds, annual repairs/inventory size, and annual scheduled maintenance/inventory size. Within the Financial category, the following metrics were compared: total CE expense/operating beds and total CE expense/total hospital expense. Within the Productivity category, the following metrics were compared: total CE full-time equivalent(FTE)/inventory size and total CE FTE/total hospital expense. These comparisons showed that:(1) While the equipment inventory in Zhejiang tends to be much smaller than USA for hospitals of comparable amount of operating beds, the numbers of repairs and scheduled maintenance per inventory size are similar;(2) The total CE expense/total hospital expense ratio is around 1% in both Zhejiang and USA; however, the total CE expense/operating beds and total CE expense/cost of equipment inventory are significantly lower in Zhejiang than USA;(3) The FTE amount in Zhejiang is significantly higher than in USA relative to both inventory size and total hospital operating expense, but significantly lower relative to the number of operating beds. The fact that repairs and scheduled maintenance are similar in Zhejiang and USA shows that CE leaders are managing equipment in comparable manner. Most of the differences found in the comparisons were traced to a few factors. First, the average length of stay in China is substantially higher than USA, which explains why hospitals in Zhejiang tend to have more operating beds but fewer pieces of equipment. Second, labor cost is significantly lower in China than USA, thus allowing Zhejiang hospitals to employ more workers than their American counterparts. Third, there is significantly difference in the cost of living between China and USA; Finally, being public entities Chinese hospitals are managed and operated in a different manner than American hospitals, which are mostly private, albeit nonprofit organizations. Nonetheless, it is interesting to note that hospitals in both areas spend roughly 1% of their total expenditure for CE. The results suggest that CE in Zhejiang is comparable to USA in terms of managerial excellence but there could be some room for improvement in financial management and productivity.展开更多
The anti-trigonometric function is used to strictly solve the uniaxial anisotropic Stoner-Wohlfarth(SW) model,which can obtain the relation of the angle α(θ) between the magnetization(the anisotropy field) and the a...The anti-trigonometric function is used to strictly solve the uniaxial anisotropic Stoner-Wohlfarth(SW) model,which can obtain the relation of the angle α(θ) between the magnetization(the anisotropy field) and the applied magnetic field.Using this analytic solution,the hysteresis loops of uniaxial anisotropic SW particles magnetized in typical directions could be numerically calculated.Then,the hysteresis loops are obtained in randomly distributed SW particle ensembles while ignoring the dipole interaction among them with the analytic solution.Finally,the correctness of the analytic solution is verified by the exact solutions of remanence,switching field,and coercivity from the SW model.The analytic solution provides an important reference for understanding the magnetizing and magnetization reversal processes of magnetic materials.展开更多
Geology is the base for highways and tunnels construction. With the fast development of national highway construction, highway tunnel construction project are more and more complex. The completeness and accuracy are e...Geology is the base for highways and tunnels construction. With the fast development of national highway construction, highway tunnel construction project are more and more complex. The completeness and accuracy are essential for the planning, design and construction of projects, while the ground information is quite poor in systematic, reliable and timely aspects. Therefore, the development of underground road tunnels, and the implementation of informationized spatial information management is urgent for highway construction. 3D geological tunnel model is intuitive, high efficient and convenience which greatly facilitates the maintenance and security of highway tunnels construction and it will be the trend for the future highway tunnel development.展开更多
Pedestrian detection is a critical challenge in the field of general object detection,the performance of object detection has advanced with the development of deep learning.However,considerable improvement is still re...Pedestrian detection is a critical challenge in the field of general object detection,the performance of object detection has advanced with the development of deep learning.However,considerable improvement is still required for pedestrian detection,considering the differences in pedestrian wears,action,and posture.In the driver assistance system,it is necessary to further improve the intelligent pedestrian detection ability.We present a method based on the combination of SSD and GAN to improve the performance of pedestrian detection.Firstly,we assess the impact of different kinds of methods which can detect pedestrians based on SSD and optimize the detection for pedestrian characteristics.Secondly,we propose a novel network architecture,namely data synthesis PS-GAN to generate diverse pedestrian data for verifying the effectiveness of massive training data to SSD detector.Experimental results show that the proposed manners can improve the performance of pedestrian detection to some extent.At last,we use the pedestrian detector to simulate a specific application of motor vehicle assisted driving which would make the detector focus on specific pedestrians according to the velocity of the vehicle.The results establish the validity of the approach.展开更多
Lead-free bismuth sodium titanate(Bi_(0.5)Na_(0.5))TiO_(3)(BNT)and related solid solutions are potential piezoelectric materials for such applications as actuators and transducers if their excellent strain responses a...Lead-free bismuth sodium titanate(Bi_(0.5)Na_(0.5))TiO_(3)(BNT)and related solid solutions are potential piezoelectric materials for such applications as actuators and transducers if their excellent strain responses and piezoelectric properties can be optimized.In this work,a large strain response of 0.61%is achieved in lead-free(0.94-x%)(Bi_(0.5)Na_(0.5))TiO_(3)-0.06BaTiO_(3)-x%NaNbO_(3)(x=0 e6,BNT-6BT-xNN)ceramics with the composition of x=3.5 in a pseudo-cubic structure.Coexistence of ferroelectric(FE)and relaxor(RE)domain structures is observed in all the unpoled ceramics and the enhanced strain response is believed to be related to the evolution of the ergodic relaxor(ER)and non-ergodic(NR)states thanks to the substitution of antiferroelectric NN.BNT-6BT-3.5NN is a critical composition near the FE/NR/ER phase boundary close to room temperature(RT)and its high strain response arises from a synergistic combination of a reversible electric-field-induced phase transition and an active domain switching in the mixed NR/ER state.This work provides new insights into the dynamic interplay between mesoscopic domains and macroscopic electrical properties in the BNT-based piezoceramics.展开更多
As an implementation tool of data intensive scientific research methods,machine learning(ML)can effectively shorten the research and development(R&D)cycle of new materials by half or even more.ML shows great poten...As an implementation tool of data intensive scientific research methods,machine learning(ML)can effectively shorten the research and development(R&D)cycle of new materials by half or even more.ML shows great potential in the combination with other scientific research technologies,especially in the processing and classification of large amounts of material data from theoretical calculation and experimental characterization.It is very important to systematically understand the research ideas of material informatics to accelerate the exploration of new materials.Here,we provide a comprehensive introduction to the most commonly used ML modeling methods in material informatics with classic cases.Then,we review the latest progresses of prediction models,which focus on new processing–structure–properties–performance(PSPP)relationships in some popular material systems,such as perovskites,catalysts,alloys,two-dimensional materials,and polymers.In addition,we summarize the recent pioneering researches in innovation of material research technology,such as inverse design,ML interatomic potentials,and microtopography characterization assistance,as new research directions of material informatics.Finally,we comprehensively provide the most significant challenges and outlooks related to the future innovation and development in the field of material informatics.This review provides a critical and concise appraisal for the applications of material informatics,and a systematic and coherent guidance for material scientists to choose modeling methods based on required materials and technologies.展开更多
The fracture toughness of rocks is a critical fracturing parameter in geo-energy exploitation playing a significant role in fracture mechanics and hydraulic fracturing.The edge-notched disk bending(ENDB)specimens are ...The fracture toughness of rocks is a critical fracturing parameter in geo-energy exploitation playing a significant role in fracture mechanics and hydraulic fracturing.The edge-notched disk bending(ENDB)specimens are employed to measure the entire range of mixed-modeⅠ/Ⅲfracture toughness of Longmaxi shale.To theoretically interpret the fracture mechanisms,this research first introduces the detailed derivations of three established fracture criteria.By distinguishing the volumetric and distortional strain energy densities,an improved three-dimensional mean strain energy density(MSED)criterion is proposed.As the critical volumetric to distortional MSED ratio decreases,the transition from tensiondominated fracture to shear-dominated fracture is observed.Our results indicate that both peak load and applied energy increase significantly with the transition from pure mode I(i.e.,tension)to pure modeⅢ(i.e.,torsion or tearing)since mode-Ⅲcracking happens in a twisted manner and mode-Ⅰcracking occurs in a coplanar manner.The macroscopic fracture signatures are consistent with those of triaxial hydraulic fracturing.The average ratio of pure mode-Ⅲfracture toughness to pure mode-Ⅰfracture toughness is 0.68,indicating that the obtained mode-Ⅲfracture resistance for a tensionbased loading system is apparent rather than true.Compared to the three mainstream fracture criteria,the present fracture criterion exhibits greater competitiveness and can successfully evaluate and predict mixed-modeⅠ/Ⅲfracture toughness of distinct materials and loading methods.展开更多
Aqueous Zinc-ion batteries(ZIBs),using zinc negative electrode and aqueous electrolyte,have attracted great attention in energy storage field due to the reliable safety and low-cost.A composite material comprised of V...Aqueous Zinc-ion batteries(ZIBs),using zinc negative electrode and aqueous electrolyte,have attracted great attention in energy storage field due to the reliable safety and low-cost.A composite material comprised of VO2·0.2H2O nanocuboids anchored on graphene sheets(VOG)is synthesized through a facile and efficient microwave-assisted solvothermal strategy and is used as aqueous ZIBs cathode material.Owing to the synergistic effects between the high conductivity of graphene sheets and the desirable structural features of VO2·0.2H2O nanocuboids,the VOG electrode has excellent electronic and ionic transport ability,resulting in superior Zn ions storage performance.The Zn/VOG system delivers ultrahigh specific capacity of 423 mAh·g^−1 at 0.25 A·g^−1 and exhibits good cycling stability of up to 1,000 cycles at 8 A·g^−1 with 87%capacity retention.Systematical structural and elemental characterizations confirm that the interlayer space of VO2·0.2H2O nanocuboids can adapt to the reversible Zn ions insertion/extraction.The as-prepared VOG composite is a promising cathode material with remarkable electrochemical performance for low-cost and safe aqueous rechargeable ZIBs.展开更多
Due to rapid changes of markets and pressures of competitions, the manufacturing companies are forced to adapt their production ways to support diversity of customer's needs and increase of new product developments. ...Due to rapid changes of markets and pressures of competitions, the manufacturing companies are forced to adapt their production ways to support diversity of customer's needs and increase of new product developments. As biological organisms are quite capable of adapting to environmental changes and stimulus, bio-inspired concepts have been recognized much suitable for adaptive manufacturing system control. This paper, therefore, proposes a novel concept of NeuroEndocrine-Inspired Manufacturing System (NEIMS). The proposed NEIMS control architecture is based on analogies with neuro-control and hormone-regulation principles. It has the capability to explicitly specify production control schemes including control points, material, information flow paths and logical operations, and to agilely deal with the frequent occurrence of unexpected disturbances at the shop floor level. From the cybernetics point of view, the control model of NEIMS indicates adaptive behavior to the changes in products demands due to external environment and malfunction of manufacturing cells as an intemal environment. Finally, a prototype system has been set up to enable the NEIMS simulation.展开更多
In this study,we report the growth of free-standing InAs nanosheets using Au catalysts in molecular beam epitaxy.Detailed structural characterizations suggest that wurtzite structured InAs nanosheets,with features of ...In this study,we report the growth of free-standing InAs nanosheets using Au catalysts in molecular beam epitaxy.Detailed structural characterizations suggest that wurtzite structured InAs nanosheets,with features of extensive{1120}surfaces,grown along the<1102>direction and adopted{0001}nanosheet/catalyst interfaces,are initiated from wurtzite structured[0001]nanowires as the inclined epitaxial growth due to relatively higher In concentrations in Au catalysts,and grown from these inclined nanostructures through catalyst-induced axial growth and their enhanced lateral growth under the high growth temperature.Based on the facts that the nanosheets contain large low energy{1120}surfaces and{0001}nanosheet/catalyst interfaces,the growth of our nanosheets is a thermodynamically driven process.This study provides new insights into fabricating free-standing Ⅲ-Ⅴ nanosheets for their applications in future nanoscale devices.展开更多
Due to the weak absorption and low light-matter interaction of MoS_(2),intrinsic MoS_(2)photodetector usually has low photoresponse,thus limiting its real application.Herein,MoS_(2)homojunction was constructed by usin...Due to the weak absorption and low light-matter interaction of MoS_(2),intrinsic MoS_(2)photodetector usually has low photoresponse,thus limiting its real application.Herein,MoS_(2)homojunction was constructed by using the chemical vapor deposition grown intrinsic MoS_(2)films and the Nb-doped MoS_(2)films.The results show that the Nb doping will induce p-type doping in MoS_(2),where the electron concentration will decrease by 2.08×10^(12)cm^(–2)after Nb doping.By investigating the photoelectric effect of MoS_(2)/Nb-doped MoS_(2)homojunction-based phototransistor,the tunability of the photoresponse,detectivity as the function of the external field,wavelength,and power of light have been studied in detail.The results show that the photoresponse and detectivity are strongly dependent on the gate voltage due to the external field tuned interlayer photoexcitation attributing to the band bending.The maximum of photoresponse can reach 51.4 A/W,the detectivity can reach 3.0×10^(12)Jones,which is two orders higher than that of intrinsic MoS_(2).Furthermore,by correlating the photoresponse and detectivity with the external field,it is found that the photodetection of MoS_(2)homojunction can be significantly tuned and exhibit well photodetection in infrared.This comprehensive work not only sheds light on the tunable photoexcitation mechanism but also offers a strategy to achieve a high-performance photodetector.展开更多
In this study, leaf-like one-dimensional InAs nanostructures were grown by the metal-organic chemical vapor deposition method. Detailed structural charac- terization suggests that the nanoleaves contain relatively low...In this study, leaf-like one-dimensional InAs nanostructures were grown by the metal-organic chemical vapor deposition method. Detailed structural charac- terization suggests that the nanoleaves contain relatively low-energy {122} or {133} mirror twins acting as their midribs and narrow sections connecting the nanoleaves and their underlying bases as petioles. Importantly, the mirror twins lead to identical lateral growth of the twinned structures in terms of crystallography and polarity, which is essential for the formation of lateral symmetrical nanoleaves. It has been found that the formation of nanoleaves is driven by catalyst energy minimization. This study provides a biomimic of leaf found in nature by fabricating a semiconductor nanoleaf.展开更多
The evolution of the nonlinear wave groups in deep water is investigated through laboratory measurements and numerical analysis.Laboratory experiments are conducted in deep-water wave tank,focusing on the characterist...The evolution of the nonlinear wave groups in deep water is investigated through laboratory measurements and numerical analysis.Laboratory experiments are conducted in deep-water wave tank,focusing on the characteristics of breaking waves arising from the evolved wave train.Some quantitative results are obtained for the significant breaking wave train,including the surface elevation time series,the local geometry,and the energy dissipation.A nonlinear model for the evolution of the wave groups in deep water is developed by adding eddy viscosity dissipation terms in the High Level Irrotational Green-Naghdi(HLIGN)equations.The results of the simulation are compared with the laboratory measurements,and good agreement is observed for the evolved wave train.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.U1637202 and52074023)the National Key R&D Program of China(No.2018YFB0905600)and the Beijing Municipal Education Commission-Natural Science Foundation Joint Key Project(No.KZ201910005003)。
文摘With the advantages of abundant resources,high specific capacity,and relatively stable cycling performance,silicon suboxides(SiO_(x) ,x<2)have been recently suggested as promising anodes for next-generation lithium-ion batteries(LIBs).SiO_(x) exhibits superior storage capability because of the presence of silicon and smaller volume change upon charge/discharge than Si owing to the buffering effect of the initial lithiation products of inert lithium oxide and lithium silicates,enabling a stable cycle life of electrodes.However,significant improvements such as overcoming issues related to volume changes in cycling and initial irreversible capacity loss and enhancing the ionic and electronic charge transport in poorly conducting SiO_(x) electrodes,are still needed to achieve the satisfactory performance required for commercial applications.This review summarizes recent progress on the cycling performance and initial coulombic efficiency of SiO_(x) .Advances in the design of particle morphology and composite composition,prelithiation and prereduction methods,and usage of electrolyte additives and optimized electrode binders are discussed.Perspectives on the promising research directions that might lead to further improvement of the electrochemical properties of SiO_(x) -based anodes are noted.This paper can serve as a basis for the research and development of high-energy-density LIBs.
文摘Thyroid cancer (TC) is the most common endocrine system cancer, of note, the overall survival of TC in China is suboptimal when comparing with the developed countries such as US (84.3%vs.98.3%), posing a great challenge among professionals involved in this field.Standardization of its diagnosis and treatment not only provides the basis for all the care givers to promote the entire level of TC management, but also is helpful in shortening the distance between China and other developed countries. A multidisciplinary team (MDT)should be involved in the comprehensive clinical management of TC, particularly for those advanced or refractory TC, which needs cooperation among members from ultrasonography, radiology, pathology, surgery.
文摘Clinical engineering(CE) has evolved rapidly over the last 25 years in China. Among the 34 provincial-level administrative units within China, the Zhejiang Province is one of the most advanced in terms of healthcare technology maintenance and management. In order to determine Zhejiang's current stage of development and opportunities for further improvement, a comparison of the performance of its CE departments was made against hospitals in the USA. Data were collected from 21 Zhejiang hospitals and compared to those from 270 acute-care hospitals in USA collected by Truven Health Analytics. The benchmarking comparison was made in three categories: operational, financial, and productivity. Within the operational category, the following metrics were compared: equipment inventory size/operating beds, annual repairs/inventory size, and annual scheduled maintenance/inventory size. Within the Financial category, the following metrics were compared: total CE expense/operating beds and total CE expense/total hospital expense. Within the Productivity category, the following metrics were compared: total CE full-time equivalent(FTE)/inventory size and total CE FTE/total hospital expense. These comparisons showed that:(1) While the equipment inventory in Zhejiang tends to be much smaller than USA for hospitals of comparable amount of operating beds, the numbers of repairs and scheduled maintenance per inventory size are similar;(2) The total CE expense/total hospital expense ratio is around 1% in both Zhejiang and USA; however, the total CE expense/operating beds and total CE expense/cost of equipment inventory are significantly lower in Zhejiang than USA;(3) The FTE amount in Zhejiang is significantly higher than in USA relative to both inventory size and total hospital operating expense, but significantly lower relative to the number of operating beds. The fact that repairs and scheduled maintenance are similar in Zhejiang and USA shows that CE leaders are managing equipment in comparable manner. Most of the differences found in the comparisons were traced to a few factors. First, the average length of stay in China is substantially higher than USA, which explains why hospitals in Zhejiang tend to have more operating beds but fewer pieces of equipment. Second, labor cost is significantly lower in China than USA, thus allowing Zhejiang hospitals to employ more workers than their American counterparts. Third, there is significantly difference in the cost of living between China and USA; Finally, being public entities Chinese hospitals are managed and operated in a different manner than American hospitals, which are mostly private, albeit nonprofit organizations. Nonetheless, it is interesting to note that hospitals in both areas spend roughly 1% of their total expenditure for CE. The results suggest that CE in Zhejiang is comparable to USA in terms of managerial excellence but there could be some room for improvement in financial management and productivity.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.91963201,12174163,and 12075102)PCSIRT(Grant No.IRT-16R35)the 111 Project(Grant No.B20063)。
文摘The anti-trigonometric function is used to strictly solve the uniaxial anisotropic Stoner-Wohlfarth(SW) model,which can obtain the relation of the angle α(θ) between the magnetization(the anisotropy field) and the applied magnetic field.Using this analytic solution,the hysteresis loops of uniaxial anisotropic SW particles magnetized in typical directions could be numerically calculated.Then,the hysteresis loops are obtained in randomly distributed SW particle ensembles while ignoring the dipole interaction among them with the analytic solution.Finally,the correctness of the analytic solution is verified by the exact solutions of remanence,switching field,and coercivity from the SW model.The analytic solution provides an important reference for understanding the magnetizing and magnetization reversal processes of magnetic materials.
文摘Geology is the base for highways and tunnels construction. With the fast development of national highway construction, highway tunnel construction project are more and more complex. The completeness and accuracy are essential for the planning, design and construction of projects, while the ground information is quite poor in systematic, reliable and timely aspects. Therefore, the development of underground road tunnels, and the implementation of informationized spatial information management is urgent for highway construction. 3D geological tunnel model is intuitive, high efficient and convenience which greatly facilitates the maintenance and security of highway tunnels construction and it will be the trend for the future highway tunnel development.
文摘Pedestrian detection is a critical challenge in the field of general object detection,the performance of object detection has advanced with the development of deep learning.However,considerable improvement is still required for pedestrian detection,considering the differences in pedestrian wears,action,and posture.In the driver assistance system,it is necessary to further improve the intelligent pedestrian detection ability.We present a method based on the combination of SSD and GAN to improve the performance of pedestrian detection.Firstly,we assess the impact of different kinds of methods which can detect pedestrians based on SSD and optimize the detection for pedestrian characteristics.Secondly,we propose a novel network architecture,namely data synthesis PS-GAN to generate diverse pedestrian data for verifying the effectiveness of massive training data to SSD detector.Experimental results show that the proposed manners can improve the performance of pedestrian detection to some extent.At last,we use the pedestrian detector to simulate a specific application of motor vehicle assisted driving which would make the detector focus on specific pedestrians according to the velocity of the vehicle.The results establish the validity of the approach.
基金supported by the Natural Science Foundation of China(Grant No.51902246,12161141012,and 12174299)the China National Key R&D Program(Grant No.2021YFB3201800 and 2020YFC0122100)+5 种基金the Natural Science Fundamental Research Project of Shaanxi Province of China(No.2019JQ590)the Key R&D Program of Shaanxi Province of China(2020GY-271)the Fundamental Research Funds for the Central Universities(xzd012020059)the“111 Project”of China(B14040)the Natural Sciences&Engineering Research Council of Canada(NSERC,Discovery Grant No.RGPIN-2017-06915)Xijiang Innovation Team Introduction Program of Zhaoqing(Jiecheng).
文摘Lead-free bismuth sodium titanate(Bi_(0.5)Na_(0.5))TiO_(3)(BNT)and related solid solutions are potential piezoelectric materials for such applications as actuators and transducers if their excellent strain responses and piezoelectric properties can be optimized.In this work,a large strain response of 0.61%is achieved in lead-free(0.94-x%)(Bi_(0.5)Na_(0.5))TiO_(3)-0.06BaTiO_(3)-x%NaNbO_(3)(x=0 e6,BNT-6BT-xNN)ceramics with the composition of x=3.5 in a pseudo-cubic structure.Coexistence of ferroelectric(FE)and relaxor(RE)domain structures is observed in all the unpoled ceramics and the enhanced strain response is believed to be related to the evolution of the ergodic relaxor(ER)and non-ergodic(NR)states thanks to the substitution of antiferroelectric NN.BNT-6BT-3.5NN is a critical composition near the FE/NR/ER phase boundary close to room temperature(RT)and its high strain response arises from a synergistic combination of a reversible electric-field-induced phase transition and an active domain switching in the mixed NR/ER state.This work provides new insights into the dynamic interplay between mesoscopic domains and macroscopic electrical properties in the BNT-based piezoceramics.
基金supported by the National Natural Science Foundation of China(12074015)the Beijing Outstanding Young Scientists Projects(BJJWZYJH01201910005018).
文摘As an implementation tool of data intensive scientific research methods,machine learning(ML)can effectively shorten the research and development(R&D)cycle of new materials by half or even more.ML shows great potential in the combination with other scientific research technologies,especially in the processing and classification of large amounts of material data from theoretical calculation and experimental characterization.It is very important to systematically understand the research ideas of material informatics to accelerate the exploration of new materials.Here,we provide a comprehensive introduction to the most commonly used ML modeling methods in material informatics with classic cases.Then,we review the latest progresses of prediction models,which focus on new processing–structure–properties–performance(PSPP)relationships in some popular material systems,such as perovskites,catalysts,alloys,two-dimensional materials,and polymers.In addition,we summarize the recent pioneering researches in innovation of material research technology,such as inverse design,ML interatomic potentials,and microtopography characterization assistance,as new research directions of material informatics.Finally,we comprehensively provide the most significant challenges and outlooks related to the future innovation and development in the field of material informatics.This review provides a critical and concise appraisal for the applications of material informatics,and a systematic and coherent guidance for material scientists to choose modeling methods based on required materials and technologies.
基金supported by National Natural Science Foundation of China(Grant Nos.52364004,52264006,and 52164001).
文摘The fracture toughness of rocks is a critical fracturing parameter in geo-energy exploitation playing a significant role in fracture mechanics and hydraulic fracturing.The edge-notched disk bending(ENDB)specimens are employed to measure the entire range of mixed-modeⅠ/Ⅲfracture toughness of Longmaxi shale.To theoretically interpret the fracture mechanisms,this research first introduces the detailed derivations of three established fracture criteria.By distinguishing the volumetric and distortional strain energy densities,an improved three-dimensional mean strain energy density(MSED)criterion is proposed.As the critical volumetric to distortional MSED ratio decreases,the transition from tensiondominated fracture to shear-dominated fracture is observed.Our results indicate that both peak load and applied energy increase significantly with the transition from pure mode I(i.e.,tension)to pure modeⅢ(i.e.,torsion or tearing)since mode-Ⅲcracking happens in a twisted manner and mode-Ⅰcracking occurs in a coplanar manner.The macroscopic fracture signatures are consistent with those of triaxial hydraulic fracturing.The average ratio of pure mode-Ⅲfracture toughness to pure mode-Ⅰfracture toughness is 0.68,indicating that the obtained mode-Ⅲfracture resistance for a tensionbased loading system is apparent rather than true.Compared to the three mainstream fracture criteria,the present fracture criterion exhibits greater competitiveness and can successfully evaluate and predict mixed-modeⅠ/Ⅲfracture toughness of distinct materials and loading methods.
基金The authors are thankful to funds from the China Postdoctoral Science Foundation(No.RZ1900011127)Qingdao Innovation Leading Talent Program and Taishan Scholars Program and Natural Science Foundation of Shandong(No.ZR2017BEM028)+4 种基金M.S.is thankful to funds from the Science Foundation of Jiangsu Province(No.BK20171169)C.W.L.thanks the support from National Natural Science Foundation of China(No.51802168)China Postdoctoral Science Foundation(No.2018M630753)Natural Science Foundation of Shandong Province(No.ZR2018BEM006)Qingdao Postdoctoral Application Research Project.
文摘Aqueous Zinc-ion batteries(ZIBs),using zinc negative electrode and aqueous electrolyte,have attracted great attention in energy storage field due to the reliable safety and low-cost.A composite material comprised of VO2·0.2H2O nanocuboids anchored on graphene sheets(VOG)is synthesized through a facile and efficient microwave-assisted solvothermal strategy and is used as aqueous ZIBs cathode material.Owing to the synergistic effects between the high conductivity of graphene sheets and the desirable structural features of VO2·0.2H2O nanocuboids,the VOG electrode has excellent electronic and ionic transport ability,resulting in superior Zn ions storage performance.The Zn/VOG system delivers ultrahigh specific capacity of 423 mAh·g^−1 at 0.25 A·g^−1 and exhibits good cycling stability of up to 1,000 cycles at 8 A·g^−1 with 87%capacity retention.Systematical structural and elemental characterizations confirm that the interlayer space of VO2·0.2H2O nanocuboids can adapt to the reversible Zn ions insertion/extraction.The as-prepared VOG composite is a promising cathode material with remarkable electrochemical performance for low-cost and safe aqueous rechargeable ZIBs.
基金supported by the Research Fund for Doctoral Program of Higher Education,China (No.20093218110020)Funding for Outstanding Doctoral Dissertation in NUAA(BCXJ10-09)the New Century Excellent Talents in University,China(NCET-08)
文摘Due to rapid changes of markets and pressures of competitions, the manufacturing companies are forced to adapt their production ways to support diversity of customer's needs and increase of new product developments. As biological organisms are quite capable of adapting to environmental changes and stimulus, bio-inspired concepts have been recognized much suitable for adaptive manufacturing system control. This paper, therefore, proposes a novel concept of NeuroEndocrine-Inspired Manufacturing System (NEIMS). The proposed NEIMS control architecture is based on analogies with neuro-control and hormone-regulation principles. It has the capability to explicitly specify production control schemes including control points, material, information flow paths and logical operations, and to agilely deal with the frequent occurrence of unexpected disturbances at the shop floor level. From the cybernetics point of view, the control model of NEIMS indicates adaptive behavior to the changes in products demands due to external environment and malfunction of manufacturing cells as an intemal environment. Finally, a prototype system has been set up to enable the NEIMS simulation.
基金the Australian Research Council,the National Key R&D Program of China(No.2016YFB0402401)the National Natural Science Foundation of China(Nos.11634009 and 11774016)+1 种基金the Key Programs of Frontier Science of the Chinese Academy of Sciences(No.QYZDJ-SSW-JSC007)The Australian Microscopy&Microanalysis Research Facility is also gratefully acknowledged for providing microscopy facilities for this study.
文摘In this study,we report the growth of free-standing InAs nanosheets using Au catalysts in molecular beam epitaxy.Detailed structural characterizations suggest that wurtzite structured InAs nanosheets,with features of extensive{1120}surfaces,grown along the<1102>direction and adopted{0001}nanosheet/catalyst interfaces,are initiated from wurtzite structured[0001]nanowires as the inclined epitaxial growth due to relatively higher In concentrations in Au catalysts,and grown from these inclined nanostructures through catalyst-induced axial growth and their enhanced lateral growth under the high growth temperature.Based on the facts that the nanosheets contain large low energy{1120}surfaces and{0001}nanosheet/catalyst interfaces,the growth of our nanosheets is a thermodynamically driven process.This study provides new insights into fabricating free-standing Ⅲ-Ⅴ nanosheets for their applications in future nanoscale devices.
基金financially supported by the National Natural Science Foundation of China(No.52002254)the Sichuan Science and Technology Foundation(Nos.2020YJ0262,2021YFH0127)+4 种基金the Chunhui plan of Ministry of Educationthe Fundamental Research Funds for the Central Universities(No.YJ201893)the Open-Foundation of Key Laboratory of Laser Device Technologythe China North Industries Group Corporation Limited(No.KLLDT202104)State Key Lab of Advanced Metals and Materials(No.2019-Z03)。
文摘Due to the weak absorption and low light-matter interaction of MoS_(2),intrinsic MoS_(2)photodetector usually has low photoresponse,thus limiting its real application.Herein,MoS_(2)homojunction was constructed by using the chemical vapor deposition grown intrinsic MoS_(2)films and the Nb-doped MoS_(2)films.The results show that the Nb doping will induce p-type doping in MoS_(2),where the electron concentration will decrease by 2.08×10^(12)cm^(–2)after Nb doping.By investigating the photoelectric effect of MoS_(2)/Nb-doped MoS_(2)homojunction-based phototransistor,the tunability of the photoresponse,detectivity as the function of the external field,wavelength,and power of light have been studied in detail.The results show that the photoresponse and detectivity are strongly dependent on the gate voltage due to the external field tuned interlayer photoexcitation attributing to the band bending.The maximum of photoresponse can reach 51.4 A/W,the detectivity can reach 3.0×10^(12)Jones,which is two orders higher than that of intrinsic MoS_(2).Furthermore,by correlating the photoresponse and detectivity with the external field,it is found that the photodetection of MoS_(2)homojunction can be significantly tuned and exhibit well photodetection in infrared.This comprehensive work not only sheds light on the tunable photoexcitation mechanism but also offers a strategy to achieve a high-performance photodetector.
文摘In this study, leaf-like one-dimensional InAs nanostructures were grown by the metal-organic chemical vapor deposition method. Detailed structural charac- terization suggests that the nanoleaves contain relatively low-energy {122} or {133} mirror twins acting as their midribs and narrow sections connecting the nanoleaves and their underlying bases as petioles. Importantly, the mirror twins lead to identical lateral growth of the twinned structures in terms of crystallography and polarity, which is essential for the formation of lateral symmetrical nanoleaves. It has been found that the formation of nanoleaves is driven by catalyst energy minimization. This study provides a biomimic of leaf found in nature by fabricating a semiconductor nanoleaf.
基金Projects supported by the National Natural Science Foundation of China(Grant No.11772099)the Heilongjiang Touyan Innovation Team Program,China.
文摘The evolution of the nonlinear wave groups in deep water is investigated through laboratory measurements and numerical analysis.Laboratory experiments are conducted in deep-water wave tank,focusing on the characteristics of breaking waves arising from the evolved wave train.Some quantitative results are obtained for the significant breaking wave train,including the surface elevation time series,the local geometry,and the energy dissipation.A nonlinear model for the evolution of the wave groups in deep water is developed by adding eddy viscosity dissipation terms in the High Level Irrotational Green-Naghdi(HLIGN)equations.The results of the simulation are compared with the laboratory measurements,and good agreement is observed for the evolved wave train.