The solution processibility of perovskites provides a costeffective and high-throughput route for fabricating state-of-the-art solar cells.However,the fast kinetics of precursor-to-perovskite transformation is suscept...The solution processibility of perovskites provides a costeffective and high-throughput route for fabricating state-of-the-art solar cells.However,the fast kinetics of precursor-to-perovskite transformation is susceptible to processing conditions,resulting in an uncontrollable variance in device performance.Here,we demonstrate a supramolecule confined approach to reproducibly fabricate perovskite films with an ultrasmooth,electronically homogeneous surface.The assembly of a calixarene capping layer on precursor surface can induce host-vip interactions with solvent molecules to tailor the desolvation kinetics,and initiate the perovskite crystallization from the sharp molecule-precursor interface.These combined effects significantly reduced the spatial variance and extended the processing window of perovskite films.As a result,the standard efficiency deviations of device-to-device and batch-to-batch devices were reduced from 0.64-0.26%to 0.67-0.23%,respectively.In addition,the perovskite films with ultrasmooth top surfaces exhibited photoluminescence quantum yield>10%and surface recombination velocities<100 cm s^(-1)for both interfaces that yielded p-i-n structured solar cells with power conversion efficiency over 25%.展开更多
To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conduc...To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°.展开更多
With China’s rapidly aging population and the growing preference for aging in place,digital monitoring technologies have emerged as potential tools to support older adults in managing their activities of daily living...With China’s rapidly aging population and the growing preference for aging in place,digital monitoring technologies have emerged as potential tools to support older adults in managing their activities of daily living(ADLs).This study explores the perceptions and acceptance of these technologies among elderly individuals living alone and their informal caregivers(ICs)in Nanshan District,Shenzhen.Grounded in the Unified Theory of Acceptance and Use of Technology(UTAUT),the study employed semi-structured and photo-elicitation interviews to analyze how performance expectancy,effort expectancy,social influence,and facilitating conditions shape technology adoption.The findings reveal clear intergenerational differences:caregivers show higher acceptance and a better understanding of the benefits and functionalities of wearable and environmental monitoring devices,while older adults often express skepticism due to concerns over privacy,usability,and cost.Many elderly participants also cite discomfort,technical complexity,and lack of training as barriers to adoption.Despite these obstacles,both groups acknowledge the potential safety and health benefits of such technologies.The study highlights the need for privacy-by-design features,customized user interfaces,and enhanced digital literacy programs tailored to both elderly users and their caregivers.The research contributes to a sociotechnical understanding of aging-in-place technologies in China and provides actionable insights for developers,policymakers,and healthcare practitioners aiming to enhance home-based elder care.展开更多
Current research on rail vehicle system vibrations primarily relies on numerical methods,with vibration transfer functions commonly derived through data fitting.However,the physical mechanisms underlying these vibrati...Current research on rail vehicle system vibrations primarily relies on numerical methods,with vibration transfer functions commonly derived through data fitting.However,the physical mechanisms underlying these vibrations are not well understood.To clarify the vibration transfer function and its characteristics,four basic input vectors are defined,and an analytical method is proposed.The vibration transfer functions of the vehicle system are solved,and their spatial coherence is analyzed.The results show that there are two spatial scales and four coherent modes in the vehicle system.The track irregularity wavelengths are combined with two spatial scales to alter the proportions of basic input vectors and then show the characteristics of spatial coherence.Four coherent modes are involved in wheel-rail force and primary suspension force;two coherent modes are involved in bogie vertical motion;and their dominant modes vary with the input frequency.On the other hand,the coherent modes involved in the bogie pitching motion and vehicle body motion are single and fixed over the whole range of frequency.This study presents an analytical method for the rapid solution of dynamic responses in vehicle systems and systematically analyzes the coherence behavior of vibration transfer functions with respect to tracking irregularity wavelengths.展开更多
The continuous white light(CWL)covering the visible and near-infrared(NIR)regions can be observed in various absorptive media excited by continuous-wave(CW)lasers.It is valuable to stimulate more efforts in unravellin...The continuous white light(CWL)covering the visible and near-infrared(NIR)regions can be observed in various absorptive media excited by continuous-wave(CW)lasers.It is valuable to stimulate more efforts in unravelling the involved photophysical processes and exploring its potential applications in diverse fields.Here,we proved that the enhanced thermal-field can boost the CWL emission.Using rare earth(RE)ions(Pr^(3+),Er^(3+)and Yb^(3+))as the photothermally active centers in Y_(2)SiO_(5)phosphor,we reveal that absorbing more excitation energy and isolating the heat conduction can lead to rapid thermal field accumulation inside the material,thereby significantly reducing the excitation threshold and enhancing white light emission.Our results might have important implications for the understanding of thermally enhanced radiation and may facilitate the CWL commercial application in night vision,bioimaging,and non-destructive detection.展开更多
AIM: To evaluate whether sorafenib use after resection impacts tumor relapse and survival in Barcelona Clinic Liver Cancer(BCLC) stage C hepatocellular carcinoma(HCC).METHODS: This retrospective study enrolled 36 male...AIM: To evaluate whether sorafenib use after resection impacts tumor relapse and survival in Barcelona Clinic Liver Cancer(BCLC) stage C hepatocellular carcinoma(HCC).METHODS: This retrospective study enrolled 36 male BCLC stage C HCC patients with portal vein thrombus and Child-Pugh class A liver function. Twentyfour patients received only surgical resection(SR), and 12 patients received oral sorafenib within 30 d after surgery. The primary outcomes were time to progression(TTP)(the time from surgical resection until HCC recurrence or extrahepatic metastases) and overall survival(OS). The secondary outcome was the rate of postoperative recurrence or metastasis. TTP and OS were analyzed using Kaplan Meier curves.RESULTS: There were no significant differences between the two groups in the serum levels of alpha-fetoprotein, copies of hepatitis B virus-DNA, preoperative laboratory results, degree of hepatic fibrosis, types of portal vein tumor thrombus, number of satellite lesions, tumor diameter, pathological results, volume of blood loss, volume of blood transfusion, or surgery time(all P > 0.05). Patients in the SR + sorafenib group had a significantly longer TTP(29 mo vs 22 mo, P = 0.041) and a significantly longer medianOS(37 mo vs 30 mo, P = 0.01) compared to patients in the SR group. The SR group had 18 cases(75%) of recurrence/metastasis while the SR + sorafenib group had six cases(50%) of recurrence/metastasis. A total of 19 patients died after surgery(five in the SR + sorafenib group and 14 in the SR group). The most common sorafenib-related adverse events were skin reactions, diarrhea, and hypertension, all of which were resolved with treatment.CONCLUSION: Sorafenib after SR was well-tolerated. Patients who received sorafenib after SR had better outcomes compared to patients who received only SR.展开更多
Many studies have investigated the selective laser melting(SLM)of AlSi10Mg and AlSi7Mg alloys,but there are still lack of researches focused on Al-Si-Mg alloys specifically tailored for SLM.In this work,a novel high M...Many studies have investigated the selective laser melting(SLM)of AlSi10Mg and AlSi7Mg alloys,but there are still lack of researches focused on Al-Si-Mg alloys specifically tailored for SLM.In this work,a novel high Mg-content AlSi8Mg3 alloy was specifically designed for SLM.The results showed that this new alloy exhibited excellent SLM processability with a lowest porosity of 0.07%.Massive lattice distortion led to a high Vickers hardness in samples fabricated at a high laser power due to the precipitation of Mg_(2)Si nanoparticles from theα-Al matrix induced by high-intensity intrinsic heat treatment during SLM.The maximum microhardness and compressive yield strength of the alloy reached HV(211±4)and(526±12)MPa,respectively.After aging treatment at 150℃,the maximum microhardness and compressive yield strength of the samples were further improved to HV(221±4)and(577±5)MPa,respectively.These values are higher than those of most known aluminum alloys fabricated by SLM.This paper provides a new idea for optimizing the mechanical properties of Al-Si-Mg alloys fabricated using SLM.展开更多
MicroRNA(miRNAs)是一类长约22nt且对基因表达具有广泛的调控作用的非编码RNA,并在神经元增殖、分化和发育成熟的过程中扮演重要角色。近年来全基因组关联研究(genome-wide association studies,GWAS)发现了众多的精神分裂症相关单核苷...MicroRNA(miRNAs)是一类长约22nt且对基因表达具有广泛的调控作用的非编码RNA,并在神经元增殖、分化和发育成熟的过程中扮演重要角色。近年来全基因组关联研究(genome-wide association studies,GWAS)发现了众多的精神分裂症相关单核苷酸多态性(single nucleotide polymorphisms,SNPs)位点多位于非编码区,表明miRNA在精神分裂症的发病过程中存在重要作用。本文综述了精神分裂症相关SNP与miRNA可能发生相互作用的4种机制(SNP位于miRNA基因、SNP位于miRNA宿主基因、SNP位于miRNA种子序列和SNP位于miRNA结合位点),为研究miRNA在精神分裂症发生发展中的作用提供参考。展开更多
For the fatigue failure and tribological property of a rolling element bearing,the contact load variation plays a significant role while the most loaded position of the bearing outer raceway takes the greatest risk of...For the fatigue failure and tribological property of a rolling element bearing,the contact load variation plays a significant role while the most loaded position of the bearing outer raceway takes the greatest risk of failure.This paper focuses on the variation in contact load on the most loaded position of the outer raceway of a gearbox bearing in high-speed train.Under operation conditions of different input speeds and torques,the dynamic contact load distribution in a gearbox bearing of high-speed train was measured by instrumenting the bearing with strain gauges.The most loaded position was identified accordingly and the features and reasons of the variation in contact load on this position were suggested.Three factors were found to have varying degrees of impact on the contact load variation under different gear meshing conditions:modal vibration of the cage or shaft,radial geometrical differences among the rollers and vibration of the gearbox housing.展开更多
The load spectrum is a crucial factor for assess-ing the fatigue reliability of in-service rolling element bear-ings in transmission systems.For a bearing in a high-speed train gearbox,a measurement technique based on...The load spectrum is a crucial factor for assess-ing the fatigue reliability of in-service rolling element bear-ings in transmission systems.For a bearing in a high-speed train gearbox,a measurement technique based on strain detection of bearing outer ring was used to instrument the bearing and determine the time histories of the distributed load in the bearing under different gear meshing conditions.Accordingly,the load spectrum of the total radial load car-ried by the bearing was compiled.The mean value and class interval of the obtained load spectrum were found to vary non-monotonously with the speed and torque of gear mesh-ing,which was considered to be caused by the vibration of the shaft and the bearing cage.As the realistic service load input of bearing life assessment,the measured load spectrum under different gear meshing conditions can be used to pre-dict gearbox bearing life realistically based on the damage-equivalent principle and actual operating conditions.展开更多
Slicing and post-treatment of SiC crystals have been a significant challenge in the integrated circuit and microelectronics industry.To compete with wire-sawing and mechanical grinding technology,a promis-ing approach...Slicing and post-treatment of SiC crystals have been a significant challenge in the integrated circuit and microelectronics industry.To compete with wire-sawing and mechanical grinding technology,a promis-ing approach combining laser slicing and laser polishing technologies has been innovatively applied to increase utilization and decrease damage defects for single crystal 4H-SiC.Significant material utiliza-tion has been achieved in the hybrid laser processes,where material loss is reduced by 75%compared to that of conventional machining technologies.Without any special process control or additional treat-ment,an internally modified layer formed by laser slicing can easily separate the 4H-SiC crystals using an external force of about∼3.6 MPa.The modified layer has been characterized using a micro-Raman method to determine residual stress.The sliced surface exhibits a combination of smooth and coarse appearances around the fluvial morphology,with an average surface roughness of over S_(a) 0.89μm.An amorphous phase surrounds the SiC substrate,with two dimensions of lattice spacing,d=0.261 nm and d=0.265 nm,confirmed by high-resolution transmission electron microscopy(HRTEM).The creation of laser-induced periodic surface nanostructures in the laser-polished surface results in a flatter surface with an average roughness of less than S_(a) 0.22μm.Due to the extreme cooling rates and multiple thermal cy-cles,dissociation of Si-C bonding,and phase separation are identified on the laser-polished surface,which is much better than that of the machining surface.We anticipate that this approach will be applicable to other high-value crystals and will have promising viability in the aerospace and semiconductor industries.展开更多
The evolution of the microstructure and toughness of APL5L X80 pipeline steel after thermal welding simulation was investigated by X-ray diffraction,electron backscatter diffraction,and transmission electron microscop...The evolution of the microstructure and toughness of APL5L X80 pipeline steel after thermal welding simulation was investigated by X-ray diffraction,electron backscatter diffraction,and transmission electron microscopy.The results indicated that primary heat-affected zones can be divided into weld,coarse-grained,fine-grained,intercritical,and sub-critical zones.The microstructure of the weld zone is mainly composed of bainitic ferrite and a small amount of granular bainite;however,the original austenite grains are distributed in the columnar grains.The structure of the coarse-grained zone is similar to that of the weld zone,but the original austenite grains are equiaxed.In contrast,the microstructure in the fine-grained zone is dominated by fine granular bainite,and the effective grain size is only 8.15μm,thus providing the highest toughness in the entire heat-affected zone.The intercritical and subcritical zones were brittle valley regions,and the microstructure was dominated by granular bainite.However,the martensite-austenite(M/A)constituents are present in island chains along the grain boundaries,and the coarse size of the M/A constituents seriously reduces the toughness.The results of the crack propagation analyzes revealed that high-angle grain boundaries can significantly slow down crack growth and change the crack direction,thereby increasing the material toughness.The impact toughness of the low-temperature tempering zone was equivalent to that of the columnar grain zone,and the impact toughness was between those of the critical and fine-grained zones.展开更多
In recent years, perovskite solar cells(PSCs) have propelled into the limelight owing to rapid development of efficiency;however, the abundant defects at the perovskite grain boundaries result in unwanted energy loss ...In recent years, perovskite solar cells(PSCs) have propelled into the limelight owing to rapid development of efficiency;however, the abundant defects at the perovskite grain boundaries result in unwanted energy loss and structural degradation. Here, the grain boundaries of perovskite polycrystalline films have been found to act as nanocapillaries for capturing perovskite quantum dots(PQDs), which enable the conformal assemble of PQDs at the top interspace between perovskite grains. The existence of PQDs passivated the surface defects, optimized the interfacial band alignments, and ultimately improved the power conversion efficiency from 19.27% to 22.47% in inverted PSCs. Our findings open up the possibility of selective assembly and structural modulation of the perovskite nanostructures towards efficient and stable PSCs.展开更多
Passivation,as a classical surface treatment technique,has been widely accepted in start-of-the-art perovskite solar cells(PSCs)that can effectively modulate the electronic and chemical property of defective perovskit...Passivation,as a classical surface treatment technique,has been widely accepted in start-of-the-art perovskite solar cells(PSCs)that can effectively modulate the electronic and chemical property of defective perovskite surface.The discovery of inorganic passivation compounds,such as oxysalts,has largely advanced the efficiency and lifetime of PSCs on account of its favorable electrical property and remarkable inherent stability,but a lack of deep understanding of how its local configuration affects the passivation effectiveness is a huge impediment for future interfacial molecular engineering.Here,we demonstrate the central-atom-dependent-passivation of oxysalt on perovskite surface,in which the central atoms of oxyacid anions dominate the interfacial oxygen-bridge strength.We revealed that the balance of local interactions between the central atoms of oxyacid anions(e.g.,N,C,S,P,Si)and the metal cations on perovskite surface(e.g.,Pb)generally determines the bond formation at oxysalt/perovskite interface,which can be understood by the bond order conservation principle.Silicate with less electronegative Si central atoms provides strong O-Pb motif and improved passivation effect,delivering a champion efficiency of 17.26%for CsPbI2Br solar cells.Our strategy is also universally effective in improving the device performance of several commonly used perovskite compositions.展开更多
The EAST superconducting tokamak, an advanced steady-state plasma physics experimental device, has been built at the Institute of Plasma Physics, Chinese Academy of Sciences. All the toroidal field magnets and poloida...The EAST superconducting tokamak, an advanced steady-state plasma physics experimental device, has been built at the Institute of Plasma Physics, Chinese Academy of Sciences. All the toroidal field magnets and poloidal field magnets, made of NbTi/Cu cable-in-conduit conductor, are cooled with forced flow supercritical helium at 3.8 K. The cryogenic system of EAST consists of a 2 kW/4 K helium refrigerator and a helium distribution system for the cooling of coils, structures, thermal shields, bus-lines, etc. The high-speed turbo-expander is an important refrigerating component of the EAST cryogenic system. In the turbo-expander, the axial supporting technology is critical for the smooth operation of the rotor bearing system. In this paper, hydrostatic thrust bearings are designed based on the axial load of the turbo-expander. Thereafter, a computational fluid dynamics-based numerical model of the aerostatic thrust bearing is set up to evaluate the bearing performance. Tilting effect on the pressure distribution and bearing load is analyzed for the thrust beating. Bearing load and stiffness are compared with different static supply pressures. The net force from the thrust bearings can be calculated for different combinations of bearing clearance and supply pressure.展开更多
A controllable crystallization is of practical importance to produce high-quality perovskite thin films with reduced structural defects.Lewis bases as electron-pair donor chemicals can strongly coordinate to lead ions...A controllable crystallization is of practical importance to produce high-quality perovskite thin films with reduced structural defects.Lewis bases as electron-pair donor chemicals can strongly coordinate to lead ions and have been extensively employed to manipulate the growth of perovskite crystals.In this work,we demonstrate a series of Lewis-base amides,for morphological regulation of methylammonium lead triiodide(MAPbI3)thin films.The screened acetamide was demonstrated to decently improve the grain size,along with a spatial distribution at grain boundaries(GBs).The mesostructured solar cells of acetamide-modified absorbers yielded an optimized power conversion efficiency(PCE)of 20.04%with a mitigated open-circuit voltage(V_(OC))deficit of 0.39 V.This work provides a facile and cost-effective strategy toward controllable fabrication of high-performance MAPbI3 solar cells.展开更多
Organometal halide perovskites have recently emerged with a huge potential for photovoltaic applications. Moreover, preparation of high-quality perovskite crystals with controlled morphology is of great significance f...Organometal halide perovskites have recently emerged with a huge potential for photovoltaic applications. Moreover, preparation of high-quality perovskite crystals with controlled morphology is of great significance for the fundamental studies such as optical and electrical properties, as well as the applications. Here, we report a one-pot solvothermal process to synthesize sheet-shaped CH3NH3PbBr3 single crystals with the lateral size of 100 μm and the thickness of 3–8 μm. Furthermore, a controlled etching behavior on the crystalline surface was demonstrated, which could be the irregular collapse of the crystalline surface caused by the local accumulation of methylammonium cations. Using this technique,CH3NH3PbBr3 single crystal sheets could be used in the various optoelectronic devices, such as nanolaser,optical sensors, photodetectors and field effect transistors.展开更多
Inverted perovskite solar cells(PSCs) have attracted broad research and industrial interest owing to their suppressed hysteresis,cost-effectiveness,and easy-fabrication.However,the issue of non-radiative recombination...Inverted perovskite solar cells(PSCs) have attracted broad research and industrial interest owing to their suppressed hysteresis,cost-effectiveness,and easy-fabrication.However,the issue of non-radiative recombination losses at the n-type interface between the perovskite and fullerene has impeded further improvement of photovoltaic performance.Here,we modify the n-type interface of FAPbI_(3) perovskite films by constructing a stereochemical two-dimensional(2D) perovskite interlayer,in which the organic cations comprise both pyridine and ammonium groups.The pyridine N donor can create stable bonding with the surface-uncoordinated Pb on the perovskite,thereby passivating the shallow-level defects and enhancing the air stability of the film.Furthermore,the pyridine N donor also offers a positive polar interface to decrease the surface work function of the perovskite film,enabling n-type modification.Ultimately,we employ a p-i-n photovoltaic(PV) device with the positive dipole interlayer at perovskite/fullerene contact and achieve remarkable photoelectric conversion efficiency(PCE) of 22.0%.展开更多
基金financially supported by the National Natural Science Foundation of China(22379044,22472053)the Science and Technology Commission of Shanghai Municipality(23520710700)+6 种基金the Key Program of the National Natural Science Foundation of China(22239001)the Shanghai Pilot Program for Basic Research(22TQ1400100-5)the ShanghaiMunicipal Natural Science Foundation(25ZR1401081)the Fundamental Research Funds for the Central Universities(JKD01251505,JKVD1251041)the Postdoctoral Fellowship Program of CPSF(GZC20250071)the Shanghai Engineering Research Center of Hierarchical Nanomaterials(18DZ2252400)the Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism(Shanghai Municipal Education Commission)。
文摘The solution processibility of perovskites provides a costeffective and high-throughput route for fabricating state-of-the-art solar cells.However,the fast kinetics of precursor-to-perovskite transformation is susceptible to processing conditions,resulting in an uncontrollable variance in device performance.Here,we demonstrate a supramolecule confined approach to reproducibly fabricate perovskite films with an ultrasmooth,electronically homogeneous surface.The assembly of a calixarene capping layer on precursor surface can induce host-vip interactions with solvent molecules to tailor the desolvation kinetics,and initiate the perovskite crystallization from the sharp molecule-precursor interface.These combined effects significantly reduced the spatial variance and extended the processing window of perovskite films.As a result,the standard efficiency deviations of device-to-device and batch-to-batch devices were reduced from 0.64-0.26%to 0.67-0.23%,respectively.In addition,the perovskite films with ultrasmooth top surfaces exhibited photoluminescence quantum yield>10%and surface recombination velocities<100 cm s^(-1)for both interfaces that yielded p-i-n structured solar cells with power conversion efficiency over 25%.
基金supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX24_0714).
文摘To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°.
文摘With China’s rapidly aging population and the growing preference for aging in place,digital monitoring technologies have emerged as potential tools to support older adults in managing their activities of daily living(ADLs).This study explores the perceptions and acceptance of these technologies among elderly individuals living alone and their informal caregivers(ICs)in Nanshan District,Shenzhen.Grounded in the Unified Theory of Acceptance and Use of Technology(UTAUT),the study employed semi-structured and photo-elicitation interviews to analyze how performance expectancy,effort expectancy,social influence,and facilitating conditions shape technology adoption.The findings reveal clear intergenerational differences:caregivers show higher acceptance and a better understanding of the benefits and functionalities of wearable and environmental monitoring devices,while older adults often express skepticism due to concerns over privacy,usability,and cost.Many elderly participants also cite discomfort,technical complexity,and lack of training as barriers to adoption.Despite these obstacles,both groups acknowledge the potential safety and health benefits of such technologies.The study highlights the need for privacy-by-design features,customized user interfaces,and enhanced digital literacy programs tailored to both elderly users and their caregivers.The research contributes to a sociotechnical understanding of aging-in-place technologies in China and provides actionable insights for developers,policymakers,and healthcare practitioners aiming to enhance home-based elder care.
基金Supported by Fundamental Research Funds for the Central Universities(Grant No.2024QYBS031)Fundamental Research Funds for the Central Universities(Grant No.2022JBQY007)。
文摘Current research on rail vehicle system vibrations primarily relies on numerical methods,with vibration transfer functions commonly derived through data fitting.However,the physical mechanisms underlying these vibrations are not well understood.To clarify the vibration transfer function and its characteristics,four basic input vectors are defined,and an analytical method is proposed.The vibration transfer functions of the vehicle system are solved,and their spatial coherence is analyzed.The results show that there are two spatial scales and four coherent modes in the vehicle system.The track irregularity wavelengths are combined with two spatial scales to alter the proportions of basic input vectors and then show the characteristics of spatial coherence.Four coherent modes are involved in wheel-rail force and primary suspension force;two coherent modes are involved in bogie vertical motion;and their dominant modes vary with the input frequency.On the other hand,the coherent modes involved in the bogie pitching motion and vehicle body motion are single and fixed over the whole range of frequency.This study presents an analytical method for the rapid solution of dynamic responses in vehicle systems and systematically analyzes the coherence behavior of vibration transfer functions with respect to tracking irregularity wavelengths.
基金supported by the National Natural Science Foundation of China(12104336,U20A20211,62075152,12004274)Fundamental Research Program of Shanxi Province(20210302124162)。
文摘The continuous white light(CWL)covering the visible and near-infrared(NIR)regions can be observed in various absorptive media excited by continuous-wave(CW)lasers.It is valuable to stimulate more efforts in unravelling the involved photophysical processes and exploring its potential applications in diverse fields.Here,we proved that the enhanced thermal-field can boost the CWL emission.Using rare earth(RE)ions(Pr^(3+),Er^(3+)and Yb^(3+))as the photothermally active centers in Y_(2)SiO_(5)phosphor,we reveal that absorbing more excitation energy and isolating the heat conduction can lead to rapid thermal field accumulation inside the material,thereby significantly reducing the excitation threshold and enhancing white light emission.Our results might have important implications for the understanding of thermally enhanced radiation and may facilitate the CWL commercial application in night vision,bioimaging,and non-destructive detection.
文摘AIM: To evaluate whether sorafenib use after resection impacts tumor relapse and survival in Barcelona Clinic Liver Cancer(BCLC) stage C hepatocellular carcinoma(HCC).METHODS: This retrospective study enrolled 36 male BCLC stage C HCC patients with portal vein thrombus and Child-Pugh class A liver function. Twentyfour patients received only surgical resection(SR), and 12 patients received oral sorafenib within 30 d after surgery. The primary outcomes were time to progression(TTP)(the time from surgical resection until HCC recurrence or extrahepatic metastases) and overall survival(OS). The secondary outcome was the rate of postoperative recurrence or metastasis. TTP and OS were analyzed using Kaplan Meier curves.RESULTS: There were no significant differences between the two groups in the serum levels of alpha-fetoprotein, copies of hepatitis B virus-DNA, preoperative laboratory results, degree of hepatic fibrosis, types of portal vein tumor thrombus, number of satellite lesions, tumor diameter, pathological results, volume of blood loss, volume of blood transfusion, or surgery time(all P > 0.05). Patients in the SR + sorafenib group had a significantly longer TTP(29 mo vs 22 mo, P = 0.041) and a significantly longer medianOS(37 mo vs 30 mo, P = 0.01) compared to patients in the SR group. The SR group had 18 cases(75%) of recurrence/metastasis while the SR + sorafenib group had six cases(50%) of recurrence/metastasis. A total of 19 patients died after surgery(five in the SR + sorafenib group and 14 in the SR group). The most common sorafenib-related adverse events were skin reactions, diarrhea, and hypertension, all of which were resolved with treatment.CONCLUSION: Sorafenib after SR was well-tolerated. Patients who received sorafenib after SR had better outcomes compared to patients who received only SR.
基金financially supported by the the National Natural Science Foundation of China(Nos.51801079 and 52001140)the Natural Science Foundation for Young Scientists of Jiangsu,China(Nos.BK20180985 and BK20180987)the Open Foundation of Zhenjiang Key Laboratory for High Technology Research on Marine Functional Films(No.ZHZ2019001)。
文摘Many studies have investigated the selective laser melting(SLM)of AlSi10Mg and AlSi7Mg alloys,but there are still lack of researches focused on Al-Si-Mg alloys specifically tailored for SLM.In this work,a novel high Mg-content AlSi8Mg3 alloy was specifically designed for SLM.The results showed that this new alloy exhibited excellent SLM processability with a lowest porosity of 0.07%.Massive lattice distortion led to a high Vickers hardness in samples fabricated at a high laser power due to the precipitation of Mg_(2)Si nanoparticles from theα-Al matrix induced by high-intensity intrinsic heat treatment during SLM.The maximum microhardness and compressive yield strength of the alloy reached HV(211±4)and(526±12)MPa,respectively.After aging treatment at 150℃,the maximum microhardness and compressive yield strength of the samples were further improved to HV(221±4)and(577±5)MPa,respectively.These values are higher than those of most known aluminum alloys fabricated by SLM.This paper provides a new idea for optimizing the mechanical properties of Al-Si-Mg alloys fabricated using SLM.
文摘MicroRNA(miRNAs)是一类长约22nt且对基因表达具有广泛的调控作用的非编码RNA,并在神经元增殖、分化和发育成熟的过程中扮演重要角色。近年来全基因组关联研究(genome-wide association studies,GWAS)发现了众多的精神分裂症相关单核苷酸多态性(single nucleotide polymorphisms,SNPs)位点多位于非编码区,表明miRNA在精神分裂症的发病过程中存在重要作用。本文综述了精神分裂症相关SNP与miRNA可能发生相互作用的4种机制(SNP位于miRNA基因、SNP位于miRNA宿主基因、SNP位于miRNA种子序列和SNP位于miRNA结合位点),为研究miRNA在精神分裂症发生发展中的作用提供参考。
基金This research was supported by the Joint Funds of the National Natural Science Foundation of China(Grant U1834202).
文摘For the fatigue failure and tribological property of a rolling element bearing,the contact load variation plays a significant role while the most loaded position of the bearing outer raceway takes the greatest risk of failure.This paper focuses on the variation in contact load on the most loaded position of the outer raceway of a gearbox bearing in high-speed train.Under operation conditions of different input speeds and torques,the dynamic contact load distribution in a gearbox bearing of high-speed train was measured by instrumenting the bearing with strain gauges.The most loaded position was identified accordingly and the features and reasons of the variation in contact load on this position were suggested.Three factors were found to have varying degrees of impact on the contact load variation under different gear meshing conditions:modal vibration of the cage or shaft,radial geometrical differences among the rollers and vibration of the gearbox housing.
基金This research was supported by the Joint Funds of the National Natural Science Foundation of China(Grant No.U1834202).
文摘The load spectrum is a crucial factor for assess-ing the fatigue reliability of in-service rolling element bear-ings in transmission systems.For a bearing in a high-speed train gearbox,a measurement technique based on strain detection of bearing outer ring was used to instrument the bearing and determine the time histories of the distributed load in the bearing under different gear meshing conditions.Accordingly,the load spectrum of the total radial load car-ried by the bearing was compiled.The mean value and class interval of the obtained load spectrum were found to vary non-monotonously with the speed and torque of gear mesh-ing,which was considered to be caused by the vibration of the shaft and the bearing cage.As the realistic service load input of bearing life assessment,the measured load spectrum under different gear meshing conditions can be used to pre-dict gearbox bearing life realistically based on the damage-equivalent principle and actual operating conditions.
基金supported by National Natural Science Foundation of China(No.62304249)a project funded by China Postdoctoral Science Foundation(No.2023M733704).
文摘Slicing and post-treatment of SiC crystals have been a significant challenge in the integrated circuit and microelectronics industry.To compete with wire-sawing and mechanical grinding technology,a promis-ing approach combining laser slicing and laser polishing technologies has been innovatively applied to increase utilization and decrease damage defects for single crystal 4H-SiC.Significant material utiliza-tion has been achieved in the hybrid laser processes,where material loss is reduced by 75%compared to that of conventional machining technologies.Without any special process control or additional treat-ment,an internally modified layer formed by laser slicing can easily separate the 4H-SiC crystals using an external force of about∼3.6 MPa.The modified layer has been characterized using a micro-Raman method to determine residual stress.The sliced surface exhibits a combination of smooth and coarse appearances around the fluvial morphology,with an average surface roughness of over S_(a) 0.89μm.An amorphous phase surrounds the SiC substrate,with two dimensions of lattice spacing,d=0.261 nm and d=0.265 nm,confirmed by high-resolution transmission electron microscopy(HRTEM).The creation of laser-induced periodic surface nanostructures in the laser-polished surface results in a flatter surface with an average roughness of less than S_(a) 0.22μm.Due to the extreme cooling rates and multiple thermal cy-cles,dissociation of Si-C bonding,and phase separation are identified on the laser-polished surface,which is much better than that of the machining surface.We anticipate that this approach will be applicable to other high-value crystals and will have promising viability in the aerospace and semiconductor industries.
基金The authors appreciate the financial support from National Key Research and Development Program of China(2017YFBO304900).
文摘The evolution of the microstructure and toughness of APL5L X80 pipeline steel after thermal welding simulation was investigated by X-ray diffraction,electron backscatter diffraction,and transmission electron microscopy.The results indicated that primary heat-affected zones can be divided into weld,coarse-grained,fine-grained,intercritical,and sub-critical zones.The microstructure of the weld zone is mainly composed of bainitic ferrite and a small amount of granular bainite;however,the original austenite grains are distributed in the columnar grains.The structure of the coarse-grained zone is similar to that of the weld zone,but the original austenite grains are equiaxed.In contrast,the microstructure in the fine-grained zone is dominated by fine granular bainite,and the effective grain size is only 8.15μm,thus providing the highest toughness in the entire heat-affected zone.The intercritical and subcritical zones were brittle valley regions,and the microstructure was dominated by granular bainite.However,the martensite-austenite(M/A)constituents are present in island chains along the grain boundaries,and the coarse size of the M/A constituents seriously reduces the toughness.The results of the crack propagation analyzes revealed that high-angle grain boundaries can significantly slow down crack growth and change the crack direction,thereby increasing the material toughness.The impact toughness of the low-temperature tempering zone was equivalent to that of the columnar grain zone,and the impact toughness was between those of the critical and fine-grained zones.
基金financially supported by the National Ten Thousand Talent Program for Young Top-notch Talentthe National Natural Science Fund for Excellent Young Scholars (52022030)+8 种基金the National Natural Science Foundation of China (51972111,52203330)the Shanghai Pilot Program for Basic Research(22TQ1400100-5)the “Dawn” Program of Shanghai Education Commission (22SG28)the Shanghai Municipal Natural Science Foundation (22ZR1418000)the Science and Technology Innovation Plan of Shanghai Science and Technology Commission(22YF1410000)the Postdoctoral Research Foundation of China(2021M701190)the Fundamental Research Funds for the Central Universities (JKM01221621, JKM01221678)the Major Science and Technology Projects of Inner Mongolia Autonomous Region(2021ZD0042)Shanghai Engineering Research Center of Hierarchical Nanomaterials (18DZ2252400)。
文摘In recent years, perovskite solar cells(PSCs) have propelled into the limelight owing to rapid development of efficiency;however, the abundant defects at the perovskite grain boundaries result in unwanted energy loss and structural degradation. Here, the grain boundaries of perovskite polycrystalline films have been found to act as nanocapillaries for capturing perovskite quantum dots(PQDs), which enable the conformal assemble of PQDs at the top interspace between perovskite grains. The existence of PQDs passivated the surface defects, optimized the interfacial band alignments, and ultimately improved the power conversion efficiency from 19.27% to 22.47% in inverted PSCs. Our findings open up the possibility of selective assembly and structural modulation of the perovskite nanostructures towards efficient and stable PSCs.
基金Ze Qing Lin and Hui Jun Lian contributed equally to this work.This work was financially supported by National Natural Science Fund for Excellent Young Scholars(52022030)International(Regional)Cooperation and Exchange Projects of the National Natural Science Foundation of China(51920105003)+4 种基金National Natural Science Fund for Distinguished Young Scholars(51725201)National Ten Thousand Talent Program for Young Top-notch Talent,National Natural Science Foundation of China(51902185,51972111)Innovation Program of Shanghai Municipal Education Commission(E00014)Shanghai Engineering Research Center of Hierarchical Nanomaterials(18DZ2252400)The authors also thank the Frontiers Science Center for Materiobiology and Dynamic Chemistry.
文摘Passivation,as a classical surface treatment technique,has been widely accepted in start-of-the-art perovskite solar cells(PSCs)that can effectively modulate the electronic and chemical property of defective perovskite surface.The discovery of inorganic passivation compounds,such as oxysalts,has largely advanced the efficiency and lifetime of PSCs on account of its favorable electrical property and remarkable inherent stability,but a lack of deep understanding of how its local configuration affects the passivation effectiveness is a huge impediment for future interfacial molecular engineering.Here,we demonstrate the central-atom-dependent-passivation of oxysalt on perovskite surface,in which the central atoms of oxyacid anions dominate the interfacial oxygen-bridge strength.We revealed that the balance of local interactions between the central atoms of oxyacid anions(e.g.,N,C,S,P,Si)and the metal cations on perovskite surface(e.g.,Pb)generally determines the bond formation at oxysalt/perovskite interface,which can be understood by the bond order conservation principle.Silicate with less electronegative Si central atoms provides strong O-Pb motif and improved passivation effect,delivering a champion efficiency of 17.26%for CsPbI2Br solar cells.Our strategy is also universally effective in improving the device performance of several commonly used perovskite compositions.
基金supported by National Natural Science Foundation of China(Nos.51406157,51506209)partially supported by the China Postdoctoral Science Foundation(No.2014M552438)
文摘The EAST superconducting tokamak, an advanced steady-state plasma physics experimental device, has been built at the Institute of Plasma Physics, Chinese Academy of Sciences. All the toroidal field magnets and poloidal field magnets, made of NbTi/Cu cable-in-conduit conductor, are cooled with forced flow supercritical helium at 3.8 K. The cryogenic system of EAST consists of a 2 kW/4 K helium refrigerator and a helium distribution system for the cooling of coils, structures, thermal shields, bus-lines, etc. The high-speed turbo-expander is an important refrigerating component of the EAST cryogenic system. In the turbo-expander, the axial supporting technology is critical for the smooth operation of the rotor bearing system. In this paper, hydrostatic thrust bearings are designed based on the axial load of the turbo-expander. Thereafter, a computational fluid dynamics-based numerical model of the aerostatic thrust bearing is set up to evaluate the bearing performance. Tilting effect on the pressure distribution and bearing load is analyzed for the thrust beating. Bearing load and stiffness are compared with different static supply pressures. The net force from the thrust bearings can be calculated for different combinations of bearing clearance and supply pressure.
基金financially supported by the National Natural Science Funds for Distinguished Young Scholar(51725201)the National Natural Science Foundation of China(51972111,51902185,51602103)+4 种基金Young Elite Scientists Sponsorship Program by CAST(2017QNRC001)International(Regional)Cooperation and Exchange Projects of the National Natural Science Foundation of China(51920105003)Innovation Program of Shanghai Municipal Education Commission(E00014)the Fundamental Research Funds for the Central Universities(JKD012016025,JKD012016022)Shanghai Engineering Research Center of Hierarchical Nanomaterials(18DZ2252400)。
文摘A controllable crystallization is of practical importance to produce high-quality perovskite thin films with reduced structural defects.Lewis bases as electron-pair donor chemicals can strongly coordinate to lead ions and have been extensively employed to manipulate the growth of perovskite crystals.In this work,we demonstrate a series of Lewis-base amides,for morphological regulation of methylammonium lead triiodide(MAPbI3)thin films.The screened acetamide was demonstrated to decently improve the grain size,along with a spatial distribution at grain boundaries(GBs).The mesostructured solar cells of acetamide-modified absorbers yielded an optimized power conversion efficiency(PCE)of 20.04%with a mitigated open-circuit voltage(V_(OC))deficit of 0.39 V.This work provides a facile and cost-effective strategy toward controllable fabrication of high-performance MAPbI3 solar cells.
基金financially supported by the National Natural Science Foundation of China (51602103)the National Natural Science Funds for Distinguished Young Scholar (51725201)+4 种基金Young Elite Scientists Sponsorship Program by CAST (2017QNRC001)Shanghai Pujiang Program (18PJD009)“Chen Guang” Project supported by Shanghai Municipal Education Commission and Shanghai Education Development Foundation (15CG26)Fundamental Research Funds for the Central Universities (222201718002)the Major Research plan of National Natural Science Foundation of China (91534202)
文摘Organometal halide perovskites have recently emerged with a huge potential for photovoltaic applications. Moreover, preparation of high-quality perovskite crystals with controlled morphology is of great significance for the fundamental studies such as optical and electrical properties, as well as the applications. Here, we report a one-pot solvothermal process to synthesize sheet-shaped CH3NH3PbBr3 single crystals with the lateral size of 100 μm and the thickness of 3–8 μm. Furthermore, a controlled etching behavior on the crystalline surface was demonstrated, which could be the irregular collapse of the crystalline surface caused by the local accumulation of methylammonium cations. Using this technique,CH3NH3PbBr3 single crystal sheets could be used in the various optoelectronic devices, such as nanolaser,optical sensors, photodetectors and field effect transistors.
基金financially supported by the National Ten Thousand Talent Program for Young Top-notch Talent,China,the National Natural Science Fund for Excellent Young Scholars,China(52022030)the National Natural Science Foundation of China,China(51972111,52203330)+7 种基金the Shanghai Pilot Program for Basic Research,China(22TQ1400100-5)the “Dawn”Program of Shanghai Education Commission,China(22SG28)the Shanghai Municipal Natural Science Foundation,China(22ZR1418000)the Science and Technology Innovation Plan of Shanghai Science and Technology Commission,China(22YF1410000)the Postdoctoral Research Foundation of China,China(2021M701190)the Fundamental Research Funds for the Central Universities,China(JKD01231632,JKVD1231041)the Major Science and Technology Projects of Inner Mongolia Autonomous Region,China(2021ZD0042)the Shanghai Engineering Research Center of Hierarchical Nanomaterials,China(18DZ2252400)。
文摘Inverted perovskite solar cells(PSCs) have attracted broad research and industrial interest owing to their suppressed hysteresis,cost-effectiveness,and easy-fabrication.However,the issue of non-radiative recombination losses at the n-type interface between the perovskite and fullerene has impeded further improvement of photovoltaic performance.Here,we modify the n-type interface of FAPbI_(3) perovskite films by constructing a stereochemical two-dimensional(2D) perovskite interlayer,in which the organic cations comprise both pyridine and ammonium groups.The pyridine N donor can create stable bonding with the surface-uncoordinated Pb on the perovskite,thereby passivating the shallow-level defects and enhancing the air stability of the film.Furthermore,the pyridine N donor also offers a positive polar interface to decrease the surface work function of the perovskite film,enabling n-type modification.Ultimately,we employ a p-i-n photovoltaic(PV) device with the positive dipole interlayer at perovskite/fullerene contact and achieve remarkable photoelectric conversion efficiency(PCE) of 22.0%.
