Modeling of the roughness in micro-nano scale and its influence have not been fully investigated, however the roughness will cause amplitude and phase errors of the radiating slot, and decrease the precision and effic...Modeling of the roughness in micro-nano scale and its influence have not been fully investigated, however the roughness will cause amplitude and phase errors of the radiating slot, and decrease the precision and efficiency of the SWA in Ku-band. Firstly, the roughness is simulated using the electromechanical coupled（EC） model. The relationship between roughness and the antenna＇s radiation properties is obtained. For verification, an antenna proto- type is manufactured and tested, and the simulation method is introduced. According to the prototype, a contrasting experiment dealing with the flatness of the radiating plane is conducted to test the simulation method. The advantage of the EC model is validated by comparisons of the EC model and two classical roughness models （sine wave and fractal function）, which shows that the EC model gives a more accurate description model for roughness, the maxi- mum error is 13%. The existence of roughness strongly broadens the beamwidth and raises the side-lobe level of SWA, which is 1.2 times greater than the ideal antenna. In addition, effect of the EC model＇s evaluation indices is investigated, the most affected scale of the roughness is found, which is 1/10 of the working wavelength. The proposed research provides the instruction for antenna designing and manufacturing.展开更多
Owing to intensified globalization and informatization,the structures of the urban scale hierarchy and urban networks between cities have become increasingly intertwined,resulting in different spatial effects.Therefor...Owing to intensified globalization and informatization,the structures of the urban scale hierarchy and urban networks between cities have become increasingly intertwined,resulting in different spatial effects.Therefore,this paper analyzes the spatial interaction between urban scale hierarchy and urban networks in China from 2019 to 2023,drawing on Baidu migration data and employing a spatial simultaneous equation model.The results reveal a significant positive spatial correlation between cities with higher hierarchy and those with greater network centrality.Within a static framework,we identify a positive interaction between urban scale hierarchy and urban network centrality,while their spatial cross-effects manifest as negative neighborhood interactions based on geographical distance and positive cross-scale interactions shaped by network connections.Within a dynamic framework,changes in urban scale hierarchy and urban networks are mutually reinforcing,thereby widening disparities within the urban hierarchy.Furthermore,an increase in a city’s network centrality had a dampening effect on the population growth of neighboring cities and network-connected cities.This study enhances understanding of the spatial organisation of urban systems and offers insights for coordinated regional development.展开更多
The(010)orientation ofβ-Ga_(2)O_(3)is a highly promising platform for next-generation lateral power electronics due to its superior theoretical transport properties.However,progress has been impeded by the unavailabi...The(010)orientation ofβ-Ga_(2)O_(3)is a highly promising platform for next-generation lateral power electronics due to its superior theoretical transport properties.However,progress has been impeded by the unavailability of large-area substrates,limiting studies to small-scale samples.Leveraging the recent emergence of 2-inch wafers,we report the first demonstration of homoepitaxial growth on a 2-inch,Fe-doped semi-insulating(010)β-Ga_(2)O_(3)substrate by metal-organic chemical vapor deposition(MOCVD).A systematic,wafer-scale characterization reveals the successful growth of a highquality epitaxial film.High-resolution x-ray diffraction shows an excellent crystalline structure,with a rocking curve full-width ranging from 21.0 arcsec to 103.0 arcsec.Atomic force microscopy confirms an atomically smooth surface with a root-mean-square roughness below 1.53 nm,displaying a distinct step-flow growth mode across the wafer.Furthermore,mercury-probe capacitance-voltage mapping indicates a well-controlled carrier concentration of~2×10~(18)cm~(-3)with a RSD of 5.12%.This work provides the first comprehensive assessment of 2-inch(010)Ga_(2)O_(3)epitaxial wafers,validating a critical material platform for the development and future manufacturing of high-performance power devices.展开更多
Surface modification for micro-nanoparticles at the atomic and close-to-atomic scales is of great importance to enhance their performance in various applications,including high-volume battery,persistent luminescence,e...Surface modification for micro-nanoparticles at the atomic and close-to-atomic scales is of great importance to enhance their performance in various applications,including high-volume battery,persistent luminescence,etc.Fluidized bed atomic layer deposition(FB-ALD)is a promising atomic-scale manufacturing technology that offers ultrathin films on large amounts of particulate materials.Nevertheless,nanoparticles tend to agglomerate due to the strong cohesive forces,which is much unfavorable to the film conformality and also hinders their real applications.In this paper,the particle fluidization process in an ultrasonic vibration-assisted FB-ALD reactor is numerically investigated from micro-scale to macro-scale through the multiscale computational fluid dynamics and discrete element method(CFD-DEM)modeling with experimental verification.Various vibration amplitudes and frequencies are investigated in terms of their effects on the fluid dynamics,distribution of particle velocity and solid volume fraction,as well as the size of agglomerates.Results show that the fluid turbulent kinetic energy,which is the key power source for the particles to obtain the kinetic energy for overcoming the interparticle agglomeration forces,can be strengthened obviously by the ultrasonic vibration.Besides,the application of ultrasonic vibration is found to reduce the mean agglomerate size in the FB.This is bound to facilitate the heat transfer and precursor diffusion in the entire FB-ALD reactor and the agglomerates,which can largely shorten the coating time and improve the film conformality as well as precursor utilization.The simulation results also agree well with our battery experimental results,verifying the validity of the multiscale CFD-DEM model.This work has provided momentous guidance to the mass manufacturing of atomic-scale particle coating from lab-scale to industrial applications.展开更多
To accelerate the development of lithium-ion batteries(LIBs),researchers should urgently exploit next-generation electrodes with high specific capacity,long cycle stability,and excellent rate performance,such as TMOs,...To accelerate the development of lithium-ion batteries(LIBs),researchers should urgently exploit next-generation electrodes with high specific capacity,long cycle stability,and excellent rate performance,such as TMOs,silicon-based materials,and alloys.Among all the modification measures,hierarchical micro-nano structure and yolk–shell structure are considered suitable and effective ways to improve the electrochemical performance of those novel materials.Herein,a facile glucose-assisted solvothermal method combined with heat treatment was implemented to synthesize hierarchical micro-nano yolk–shell V_(2)O_(3).The special-structured material exhibited higher specific capacity,better structure stability,and faster electrochemical kinetics compared with nanosheet-structured and micro-nano-cluster-structured V_(2)O_(3).When used as an anode for LIB,mnYS-V_(2)O_(3)delivered high specific capacity of 650.1 mA h g^(-1)after over 500 cycles at a current density of 100 mA g^(-1),with a retention of 93.4%.Moreover,the morphology evolution mechanism of micro-nano structure and yolk–shell structure was investigated in this work,which is beneficial to the design of other mnYS-structured TMOs.展开更多
Inspired by the ubiquitous helical structures in nature,research on artificial helices has attracted increasing attention.As a unique and complex three-dimensional(3D)geometry in the microscopic world,the micro-/nano ...Inspired by the ubiquitous helical structures in nature,research on artificial helices has attracted increasing attention.As a unique and complex three-dimensional(3D)geometry in the microscopic world,the micro-/nano helix has significant advantages in wide applications due to its distinctive properties at the micro-scale.Micro-/nanotechnology is advancing rapidly.The geometric complexity of helical structure poses technical challenges for the manufacturing at the micro-/nanoscale,requiring some emerging manufacturing techniques.In this review,we systematically classify and summarize existing manufacturing methods for micro/nano helical structures and their underlying mechanisms.Based on the unique physical properties of helical structures at the microscale,their latest applications are analyzed across different fields.Finally,we conclude the challenges and future research directions of micro-/nano helices in manufacturing methods and applications.展开更多
Organic-rich shale is a significant potential source of oil and gas that requires development through in situ conversion technology.However,the evolution patterns of the internal three-dimensional(3D)pore structure an...Organic-rich shale is a significant potential source of oil and gas that requires development through in situ conversion technology.However,the evolution patterns of the internal three-dimensional(3D)pore structure and kerogen distribution at high temperatures are not well understood,making it difficult to microscopically explain the evolution of the flow conductivity in organic-rich shale at high temperatures.This study utilizes high-resolution X-ray computed tomography(micro-nano CT)to obtain the distribution of pores,kerogen,and inorganic matter at different temperatures.Combined with the pyrolysis results for the rock,the evolution of the pore structure at various temperatures is quantitatively analyzed.Based on three-phase segmentation technology,a model of kerogen distribution in organicrich shale is established by dividing the kerogen into clustered kerogen and dispersed kerogen stored in the inorganic matter and the pores into inorganic pores and organic pores within the kerogen skeleton.The results show that the inorganic pores in organic-rich shale evolve through three stages as the temperature increases:kerogen pyrolysis(200-400℃),clay mineral decomposition(400-600℃),and carbonate mineral decomposition(600-800℃).The inorganic pores porosity sequentially increases from 3%to 11.4%,13.1%,and 15.4%,and the roughness and connectivity of the inorganic pores gradually increase during this process.When the pyrolysis temperature reaches 400℃,the volume of clustered kerogen decreases from 25%to 12.5%.During this process,the relative density of kerogen decreases from9.5 g/cm^(3) in its original state to 5.4 g/cm^(3),while the kerogen skeleton density increases from 1.15 g/cm^(3) in its original state to 1.54 g/cm^(3).Correspondingly,7%-8%of organic pores develop within the clustered kerogen,accounting for approximately 50%of the volume of clustered kerogen.In addition,approximately 30%of the kerogen in organic-rich shale exists in the form of dispersed kerogen within inorganic matter,and its variation trend is similar to that of clustered kerogen,rapidly decreasing from 200 to 400℃ and stabilizing above 400℃.The results of this study provide an essential microscopic theoretical basis for the industrial development of organic-rich shale resources.展开更多
Mason Reset(MR),a groundbreaking invention by Clesson E.Mason in 1930 that later became a part of“the universal approach to process control instrumentation”,is revisited in this paper and is shown to consists of thr...Mason Reset(MR),a groundbreaking invention by Clesson E.Mason in 1930 that later became a part of“the universal approach to process control instrumentation”,is revisited in this paper and is shown to consists of three actions:fast(errorcorrection),medium(negative feedback for expanded proportional band)and slow(reset for zero steady-state error).The focus of the paper is on the reset action,generated from a positive feedback loop,and its underlying principles with profound implications to our understanding and practice of automatic control,both basic and advanced.For example,we note that reset control and integral control,contrary to common belief,differ fundamentally in design principle and in practicality.Such difference comes to a head in the event of integrator windup:while reset windup is a problem of actuator saturation,the integrator windup is a runaway situation due to controller instability.In fact,there is no advantage gained in replacing MR with an integrator.In other words,one should not integrate the error directly as in standard PID,since doing so makes the closed-loop system internally unstable.With MR-based control formulated in this paper,there is no such threat of instability and,therefore,no need for any anti-windup mechanisms.Furthermore,the integral control is made scalable in this framework as a tradeoff between the steady-state accuracy and the controller stability.This leads to a novel MR-based control design,scalable in gain and in time to accommodate various process characteristics and design specifications.Simple in construction and transparent in principle,this MR-based control,as a basic framework of design,is readily deployable in scale.展开更多
Multiscale shell structure design is a rational and promising way to regulate the performance of hollow spheres in terms of both functionality and structural robustness,but it remains a big challenge to realize micro-...Multiscale shell structure design is a rational and promising way to regulate the performance of hollow spheres in terms of both functionality and structural robustness,but it remains a big challenge to realize micro-nano engineering of the thin shell while maintaining the low density.In this work,the divisional shell design strategy was adopted to obtain the glass-cobalt-cobalt sulfide composite hollow microspheres(CSH),and an unprecedented stepwise high-temperature chemical reaction-induced aggregation and sub-sequent volume expansion strategy was developed to achieve rational regulation of core-shell structured cobalt-cobalt sulfide building units(BU)assembled on hollow glass microspheres.Special attention has been paid to the sulfidation degree-induced volume control with the underlying mechanism of volume expansion during chemical conversion from metallic cobalt to cobalt sulfide.The electromagnetic prop-erty was found to depend largely on the sulfidation degree due to the volume expansion-induced inter-connecting status regulation among the BU.When evaluated as microwave absorbent,an optimized broad bandwidth of 5.12 GHz and a minimum reflection loss(RLmin)of-45.58 dB of our CSH can be achieved at a thin matching thickness of 1.67 mm and a low filling ratio of 20.04 wt%.In addition to functionality,the divisional shell design also brings the CSH high structural strength(92.36%survival rate at a high hydrostatic pressure of 20 MPa)at low density(0.73 g cm^(-3)).展开更多
The indiscriminate discharge of industrial wastewater and oil leakage accidents cause serious water pollution and pose threats to aquatic ecosystems and sanitary environments.The oily wastewater system is complex and ...The indiscriminate discharge of industrial wastewater and oil leakage accidents cause serious water pollution and pose threats to aquatic ecosystems and sanitary environments.The oily wastewater system is complex and most membrane materials cannot separate various oil-water mixtures.S erious membrane pollution would cause a decrease in separation flux.We proposed a pre-identified organic hydrogel surface prepared by micro-nano manufacturing technology for selective oil/water separation with ultra-high separating flux.Stimulated by water,the prepared surface is superhydrophilic-underwater superoleophobic,allowing water to pass through,and stimulated by oil,the prepared surface is superoleophilic-underoil superhydrophobic,allowing oil to pass through.Thus,based on the special solvent-responsive property,the prepared surface has a pre-identified function for water and oil,and could achieve the capture of oil droplets in water and water droplets in oil.In addition,the surface maintains an ultra-high separating efficiency and flux of about 99.85%and 17750 L·m^(-2)·h^(-1),and even after continuous cycles without cleaning,it could keep 99.1%and 16000 L·m^(-2)·h^(-1)due to the excellent anti-fouling ability.This study provides new ideas and methods for designing intelligent oil-water separation devices,and further guidance for achieving on-demand oily wastewater treatment.展开更多
An improved model based on you only look once version 8(YOLOv8)is proposed to solve the problem of low detection accuracy due to the diversity of object sizes in optical remote sensing images.Firstly,the feature pyram...An improved model based on you only look once version 8(YOLOv8)is proposed to solve the problem of low detection accuracy due to the diversity of object sizes in optical remote sensing images.Firstly,the feature pyramid network(FPN)structure of the original YOLOv8 mode is replaced by the generalized-FPN(GFPN)structure in GiraffeDet to realize the"cross-layer"and"cross-scale"adaptive feature fusion,to enrich the semantic information and spatial information on the feature map to improve the target detection ability of the model.Secondly,a pyramid-pool module of multi atrous spatial pyramid pooling(MASPP)is designed by using the idea of atrous convolution and feature pyramid structure to extract multi-scale features,so as to improve the processing ability of the model for multi-scale objects.The experimental results show that the detection accuracy of the improved YOLOv8 model on DIOR dataset is 92%and mean average precision(mAP)is 87.9%,respectively 3.5%and 1.7%higher than those of the original model.It is proved the detection and classification ability of the proposed model on multi-dimensional optical remote sensing target has been improved.展开更多
Background The patient-reported Dimensional Anhedonia Rating Scale(DARS)has been adapted into Chinese,so there is a need to evaluate its measurement properties in a Chinese population.Aims To evaluate the reliability ...Background The patient-reported Dimensional Anhedonia Rating Scale(DARS)has been adapted into Chinese,so there is a need to evaluate its measurement properties in a Chinese population.Aims To evaluate the reliability and validity of the DARS among Chinese individuals with major depressive disorder(MDD)and its treatment sensitivity in a prospective clinical study.Methods Data were from a multicentre,prospective clinical study(NCT03294525),which recruited both patients with MDD,who were followed for 8 weeks,and healthy controls(HCs),assessed at baseline only.The analysis included confirmatory factor analysis,validity and sensitivity to change.Results Patients’mean(standard deviation(SD))age was 34.8(11.0)years,with 68.7%being female.75.2%of patients with MDD had melancholic features,followed by 63.8%with anxious distress.Patients had experienced MDD for a mean(SD)of 9.2(18)months.DARS scores covered the full range of severity with no major floor or ceiling effects.Confirmatory factor analysis showed adequate fit statistics(comparative fit index 0.976,goodness-of-fit index 0.935 and root mean square error of approximation 0.055).Convergent validity with anhedonia-related measures was confirmed.While the correlation between the DARS and the Hamilton Depression Rating Scale was not strong(r=0.31,baseline),the DARS was found to differentiate between levels of depression.Greater improvements in DARS scores were seen with the Hamilton Rating Scale for Depression responder group(effect size 1.16)compared with the non-responder group(effect size 0.46).Conclusions This study comprehensively evaluated the measurement properties of the DARS using a Chinese population with MDD.Overall,the Chinese version of DARS demonstrates good psychometric properties and has been found to be responsive to change during antidepressant treatment.The DARS is a suitable scale for assessing patient-reported anhedonia in future clinical trials.展开更多
Background The effectiveness of life skills-based prevention programs to prevent substance addiction has been underexplored in Türkiye,likely in part due to the lack of validated measurement tools developed speci...Background The effectiveness of life skills-based prevention programs to prevent substance addiction has been underexplored in Türkiye,likely in part due to the lack of validated measurement tools developed specifically for that purpose.Therefore,the aim of this study is to develop a tool to measure life skills for middle school students.The present study aims to test the factorial structure,reliability,convergent and discriminant validity,and measurement invariance across gender and age groups of the Green Crescent Life Skills(GCLS)Scale.Methods The study was conducted in Istanbul with two different sample groups.The first sample consisted of 566 and the second sample consisted of 885 middle school students.In the study,exploratory factor analysis(EFA)was applied to the first sample,and confirmatory factor analysis(CFA)was applied to the second sample to test the factorial structure of the scale.Convergent and discriminant validity were examined to provide evidence for construct-based validity.The reliability of the scale was assessed with Cronbach’sα,composite reliability,McDonald’sω,and test-retest.Results The EFA results showed that the scale consisted of four factors(self-awareness,coping with negative emotions,thinking skills,and peer relations).CFA results also confirmed this structure.The results revealed a significant positive correlation(r=0.52,p<0.01)between life skills and avoidance self-efficacy scores,as well as a significant negative correlation(r=−0.53,p<0.01)between life skills and attitude toward drug use scores.Additionally,it was found that measurement invariances based on gender and age groups were provided.It was determined that all sub-dimensions had sufficient reliability levels.Conclusion The findings of this validation study show that the GCLS Scale,which assesses four skills in a self-reported format,is a valid and reliable scale with considerable potential utility in monitoring life skills in Turkish adolescent populations.展开更多
Flow boiling in open microchannels offers highly efficient heat transfer performance and has attracted increasing attention in the fields of heat transfer and thermalmanagement of electronic devices in recent years.Ho...Flow boiling in open microchannels offers highly efficient heat transfer performance and has attracted increasing attention in the fields of heat transfer and thermalmanagement of electronic devices in recent years.However,the continuous rise in power density of electronic components imposesmore stringent requirements on the heat transfer capability of microchannel flow boiling.HFE-7100,a dielectric coolant with favorable thermophysical properties,has become a focal point of research for enhancing flow boiling performance in open microchannels.The flow boiling heat transfer performance ofHFE-7100 was investigated in this study by fabricating micro-nano composite structures on the bottom surface of open microchannels using laser ablation technology.Based on visualization results,a comparative analysis was conducted on the bubble dynamics and flow pattern characteristics of HFE-7100 flow boiling in micronano structured open microchannels(MNSOMC)and smooth-surface open microchannels(SSOMC),to elucidate the enhancement mechanism of micro-nano structures on flow boiling heat transfer in open microchannels.The results indicate that the surface structures and strong wettability of MNSOMC accelerated bubble nucleation and departure.Moreover,bubbles in the channel tended to coalesce along the flow direction,forming elongated slug bubbles with high aspect ratios,which enabled efficient thin film evaporation in conjunction with intense nucleate boiling,thereby significantly enhancing flow boiling heat transfer.Under the experimental conditions of this study,the maximum enhancements in the heat transfer coefficient(HTC)and critical heat flux(CHF)of HFE-7100 inMNSOMC were 33.4%and 133.1%,respectively,with the CHF reaching up to 1542.3 kW⋅m^(−2).Furthermore,due to the superior wettability and capillary wicking capability of the micro-nano composite structures,the significant enhancement in flow boiling heat transfer was achieved without incurring a noticeable pressure drop penalty.展开更多
Micro-nano Earth Observation Satellite(MEOS)constellation has the advantages of low construction cost,short revisit cycle,and high functional density,which is considered a promising solution for serving rapidly growin...Micro-nano Earth Observation Satellite(MEOS)constellation has the advantages of low construction cost,short revisit cycle,and high functional density,which is considered a promising solution for serving rapidly growing observation demands.The observation Scheduling Problem in the MEOS constellation(MEOSSP)is a challenging issue due to the large number of satellites and tasks,as well as complex observation constraints.To address the large-scale and complicated MEOSSP,we develop a Two-Stage Scheduling Algorithm based on the Pointer Network with Attention mechanism(TSSA-PNA).In TSSA-PNA,the MEOS observation scheduling is decomposed into a task allocation stage and a single-MEOS scheduling stage.In the task allocation stage,an adaptive task allocation algorithm with four problem-specific allocation operators is proposed to reallocate the unscheduled tasks to new MEOSs.Regarding the single-MEOS scheduling stage,we design a pointer network based on the encoder-decoder architecture to learn the optimal singleMEOS scheduling solution and introduce the attention mechanism into the encoder to improve the learning efficiency.The Pointer Network with Attention mechanism(PNA)can generate the single-MEOS scheduling solution quickly in an end-to-end manner.These two decomposed stages are performed iteratively to search for the solution with high profit.A greedy local search algorithm is developed to improve the profits further.The performance of the PNA and TSSA-PNA on singleMEOS and multi-MEOS scheduling problems are evaluated in the experiments.The experimental results demonstrate that PNA can obtain the approximate solution for the single-MEOS scheduling problem in a short time.Besides,the TSSA-PNA can achieve higher observation profits than the existing scheduling algorithms within the acceptable computational time for the large-scale MEOS scheduling problem.展开更多
Loneliness is a complex and usually unpleasant emotional response to isolation,which has been considered the latest global health epidemic exacerbated by the coronavirus disease 2019 pandemic,affecting nearly twothird...Loneliness is a complex and usually unpleasant emotional response to isolation,which has been considered the latest global health epidemic exacerbated by the coronavirus disease 2019 pandemic,affecting nearly twothirds of older adults.Some profound health implications carried by loneliness include depression,cognitive impairment,hypertension and frailty.Across the world,there is no consensus definition of loneliness,and its measure is based on the phenomenological perspective of the individual.The 20-item University of California Los Angeles Loneliness Scale version 3(UCLA-20)is the most common measure.This scale demonstrates acceptable psychometric properties but is too long and complex for a phone interview.This paper addresses the increasing need to shorten this scale by adopting classical item response theory and network psychometrics to advance scale development.Through an item reduction analysis,we trimmed the original scale into an effective short form,which is as valid as the original one.With respondents’time at a premium in most research nowadays,this shortform scale is an efficient and practical alternative to the original UCLA-20.展开更多
BACKGROUND During the gradual decline of physical and social functioning associated with end-stage renal disease,patients might experience a premonition of impending death,resulting in a series of pre-mourning grief r...BACKGROUND During the gradual decline of physical and social functioning associated with end-stage renal disease,patients might experience a premonition of impending death,resulting in a series of pre-mourning grief responses called preparatory grief.The preparatory grief in advanced cancer patients(PGAC)scale is the most widely used preparatory grief scale for patients on hemodialysis in China.AIM To verify the reliability and validity of the PGAC scale in patients on hemodialysis.METHODS In total,327 patients undergoing regular hemodialysis in the blood purification center of three grade-A tertiary hospitals in Guangdong and Guizhou provinces were selected by convenience sampling.The assessment was administered using the general information questionnaire and the Chinese version of PGAC.SPSS 25.0 and Amos 24.0 were used for item analysis,confirmatory factor analysis(CFA),convergent validity,and internal consistency reliability estimation.RESULTS In the modified Chinese version of PGAC,7 dimensions covering 27 total items were retained.CFA revealed a good fit of the factor model(chi-square degree of freedom=2.056,standardized root mean square residual=0.0479,root mean square error of approximation=0.0570,GFI=0.872,AGFI=0.841,IFI=0.931,CFI=0.930,TLI=0.919).The factor loadings of the items ranged 0.503-0.884.The composite reliability ranged 0.664-0.914,and the average variance extracted ranged 0.366-0.747.Cronbach’sαof the scale was 0.945,and Cronbach’sαfor various dimensions ranged 0.662-0.914.CONCLUSION The modified PGAC has good reliability and validity,and it can effectively measure preparatory grief in patients on hemodialysis.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.51305322,51405364,51475348)
文摘Modeling of the roughness in micro-nano scale and its influence have not been fully investigated, however the roughness will cause amplitude and phase errors of the radiating slot, and decrease the precision and efficiency of the SWA in Ku-band. Firstly, the roughness is simulated using the electromechanical coupled（EC） model. The relationship between roughness and the antenna＇s radiation properties is obtained. For verification, an antenna proto- type is manufactured and tested, and the simulation method is introduced. According to the prototype, a contrasting experiment dealing with the flatness of the radiating plane is conducted to test the simulation method. The advantage of the EC model is validated by comparisons of the EC model and two classical roughness models （sine wave and fractal function）, which shows that the EC model gives a more accurate description model for roughness, the maxi- mum error is 13%. The existence of roughness strongly broadens the beamwidth and raises the side-lobe level of SWA, which is 1.2 times greater than the ideal antenna. In addition, effect of the EC model＇s evaluation indices is investigated, the most affected scale of the roughness is found, which is 1/10 of the working wavelength. The proposed research provides the instruction for antenna designing and manufacturing.
基金Under the auspices of the National Natural Science Foundation of China(No.42371222,41971167)Fundamental Scientific Research Funds of Central China Normal University(No.CCNU24ZZ120)。
文摘Owing to intensified globalization and informatization,the structures of the urban scale hierarchy and urban networks between cities have become increasingly intertwined,resulting in different spatial effects.Therefore,this paper analyzes the spatial interaction between urban scale hierarchy and urban networks in China from 2019 to 2023,drawing on Baidu migration data and employing a spatial simultaneous equation model.The results reveal a significant positive spatial correlation between cities with higher hierarchy and those with greater network centrality.Within a static framework,we identify a positive interaction between urban scale hierarchy and urban network centrality,while their spatial cross-effects manifest as negative neighborhood interactions based on geographical distance and positive cross-scale interactions shaped by network connections.Within a dynamic framework,changes in urban scale hierarchy and urban networks are mutually reinforcing,thereby widening disparities within the urban hierarchy.Furthermore,an increase in a city’s network centrality had a dampening effect on the population growth of neighboring cities and network-connected cities.This study enhances understanding of the spatial organisation of urban systems and offers insights for coordinated regional development.
基金supported by the National Natural Science Foundation of China(Grant Nos.U23A20358,62474170,61925110,62404214,and 62234007)the University of Science and Technology of China(USTC)Research Funds of the Double First-Class Initiative(Grant No.WK2100000055)+2 种基金the Project of the 46t hResearch Institute of CETC(Grant No.WDZC202446007)the JieBang Headed Project of Changsha City Hunan Province(Grant No.kq2301006)the Opening Project and the Key Laboratory of Nano devices and Applications in Suzhou Institute of Nano-Tech and NanoBionics of CAS。
文摘The(010)orientation ofβ-Ga_(2)O_(3)is a highly promising platform for next-generation lateral power electronics due to its superior theoretical transport properties.However,progress has been impeded by the unavailability of large-area substrates,limiting studies to small-scale samples.Leveraging the recent emergence of 2-inch wafers,we report the first demonstration of homoepitaxial growth on a 2-inch,Fe-doped semi-insulating(010)β-Ga_(2)O_(3)substrate by metal-organic chemical vapor deposition(MOCVD).A systematic,wafer-scale characterization reveals the successful growth of a highquality epitaxial film.High-resolution x-ray diffraction shows an excellent crystalline structure,with a rocking curve full-width ranging from 21.0 arcsec to 103.0 arcsec.Atomic force microscopy confirms an atomically smooth surface with a root-mean-square roughness below 1.53 nm,displaying a distinct step-flow growth mode across the wafer.Furthermore,mercury-probe capacitance-voltage mapping indicates a well-controlled carrier concentration of~2×10~(18)cm~(-3)with a RSD of 5.12%.This work provides the first comprehensive assessment of 2-inch(010)Ga_(2)O_(3)epitaxial wafers,validating a critical material platform for the development and future manufacturing of high-performance power devices.
基金supported by the National Natural Science Foundation of China(51835005 and 51911540476)National Key Research and Development Program of China(2020YFB2010401)+3 种基金Hubei Province Natural Science Foundation for innovative research groups(2020CFA030)Independent Innovation Research Fund of HUST(2019kfyXMBZ025)Tencent Foundationthe Engineering and Physical Sciences Research Council project(EP/T019085/1).
文摘Surface modification for micro-nanoparticles at the atomic and close-to-atomic scales is of great importance to enhance their performance in various applications,including high-volume battery,persistent luminescence,etc.Fluidized bed atomic layer deposition(FB-ALD)is a promising atomic-scale manufacturing technology that offers ultrathin films on large amounts of particulate materials.Nevertheless,nanoparticles tend to agglomerate due to the strong cohesive forces,which is much unfavorable to the film conformality and also hinders their real applications.In this paper,the particle fluidization process in an ultrasonic vibration-assisted FB-ALD reactor is numerically investigated from micro-scale to macro-scale through the multiscale computational fluid dynamics and discrete element method(CFD-DEM)modeling with experimental verification.Various vibration amplitudes and frequencies are investigated in terms of their effects on the fluid dynamics,distribution of particle velocity and solid volume fraction,as well as the size of agglomerates.Results show that the fluid turbulent kinetic energy,which is the key power source for the particles to obtain the kinetic energy for overcoming the interparticle agglomeration forces,can be strengthened obviously by the ultrasonic vibration.Besides,the application of ultrasonic vibration is found to reduce the mean agglomerate size in the FB.This is bound to facilitate the heat transfer and precursor diffusion in the entire FB-ALD reactor and the agglomerates,which can largely shorten the coating time and improve the film conformality as well as precursor utilization.The simulation results also agree well with our battery experimental results,verifying the validity of the multiscale CFD-DEM model.This work has provided momentous guidance to the mass manufacturing of atomic-scale particle coating from lab-scale to industrial applications.
基金supported by the National Natural Science Foundation of China(NSFC No.52372200)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_0360).
文摘To accelerate the development of lithium-ion batteries(LIBs),researchers should urgently exploit next-generation electrodes with high specific capacity,long cycle stability,and excellent rate performance,such as TMOs,silicon-based materials,and alloys.Among all the modification measures,hierarchical micro-nano structure and yolk–shell structure are considered suitable and effective ways to improve the electrochemical performance of those novel materials.Herein,a facile glucose-assisted solvothermal method combined with heat treatment was implemented to synthesize hierarchical micro-nano yolk–shell V_(2)O_(3).The special-structured material exhibited higher specific capacity,better structure stability,and faster electrochemical kinetics compared with nanosheet-structured and micro-nano-cluster-structured V_(2)O_(3).When used as an anode for LIB,mnYS-V_(2)O_(3)delivered high specific capacity of 650.1 mA h g^(-1)after over 500 cycles at a current density of 100 mA g^(-1),with a retention of 93.4%.Moreover,the morphology evolution mechanism of micro-nano structure and yolk–shell structure was investigated in this work,which is beneficial to the design of other mnYS-structured TMOs.
基金supported by the National Key R&D Program of China(Grant No.2022YFB4701200)the National Natural Science Foundation of China(Grant Nos.52335003,52405011 and U22A20176)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(Grant Nos.2022B1515120078 and 2023A1515110313)the Shenzhen Natural Science Fund(the Stable Support Plan Program,Grant No.GXWD20231129161359002)the Shenzhen Science and Technology Program(Grant No.KQTD20210811090146075)Pre-research Task of State Key Laboratory of Robotics and Systems(HIT)(Grant No.SKLRS202421B).
文摘Inspired by the ubiquitous helical structures in nature,research on artificial helices has attracted increasing attention.As a unique and complex three-dimensional(3D)geometry in the microscopic world,the micro-/nano helix has significant advantages in wide applications due to its distinctive properties at the micro-scale.Micro-/nanotechnology is advancing rapidly.The geometric complexity of helical structure poses technical challenges for the manufacturing at the micro-/nanoscale,requiring some emerging manufacturing techniques.In this review,we systematically classify and summarize existing manufacturing methods for micro/nano helical structures and their underlying mechanisms.Based on the unique physical properties of helical structures at the microscale,their latest applications are analyzed across different fields.Finally,we conclude the challenges and future research directions of micro-/nano helices in manufacturing methods and applications.
基金the financial support offered by the National Oil Shale Exploitation R&D Center Open Fund Project(Grant No.33550000-24-ZC0613-0055)National Key R&D Program of China(Grant No.2019YFA0705502,Grant No.2019YFA0705501)+1 种基金Science and technology research project of Education Department of Jilin Province(Grant No.JJKH20231185K)the National Natural Science Fund project of China(Grant No.4210020395,51974334)。
文摘Organic-rich shale is a significant potential source of oil and gas that requires development through in situ conversion technology.However,the evolution patterns of the internal three-dimensional(3D)pore structure and kerogen distribution at high temperatures are not well understood,making it difficult to microscopically explain the evolution of the flow conductivity in organic-rich shale at high temperatures.This study utilizes high-resolution X-ray computed tomography(micro-nano CT)to obtain the distribution of pores,kerogen,and inorganic matter at different temperatures.Combined with the pyrolysis results for the rock,the evolution of the pore structure at various temperatures is quantitatively analyzed.Based on three-phase segmentation technology,a model of kerogen distribution in organicrich shale is established by dividing the kerogen into clustered kerogen and dispersed kerogen stored in the inorganic matter and the pores into inorganic pores and organic pores within the kerogen skeleton.The results show that the inorganic pores in organic-rich shale evolve through three stages as the temperature increases:kerogen pyrolysis(200-400℃),clay mineral decomposition(400-600℃),and carbonate mineral decomposition(600-800℃).The inorganic pores porosity sequentially increases from 3%to 11.4%,13.1%,and 15.4%,and the roughness and connectivity of the inorganic pores gradually increase during this process.When the pyrolysis temperature reaches 400℃,the volume of clustered kerogen decreases from 25%to 12.5%.During this process,the relative density of kerogen decreases from9.5 g/cm^(3) in its original state to 5.4 g/cm^(3),while the kerogen skeleton density increases from 1.15 g/cm^(3) in its original state to 1.54 g/cm^(3).Correspondingly,7%-8%of organic pores develop within the clustered kerogen,accounting for approximately 50%of the volume of clustered kerogen.In addition,approximately 30%of the kerogen in organic-rich shale exists in the form of dispersed kerogen within inorganic matter,and its variation trend is similar to that of clustered kerogen,rapidly decreasing from 200 to 400℃ and stabilizing above 400℃.The results of this study provide an essential microscopic theoretical basis for the industrial development of organic-rich shale resources.
文摘Mason Reset(MR),a groundbreaking invention by Clesson E.Mason in 1930 that later became a part of“the universal approach to process control instrumentation”,is revisited in this paper and is shown to consists of three actions:fast(errorcorrection),medium(negative feedback for expanded proportional band)and slow(reset for zero steady-state error).The focus of the paper is on the reset action,generated from a positive feedback loop,and its underlying principles with profound implications to our understanding and practice of automatic control,both basic and advanced.For example,we note that reset control and integral control,contrary to common belief,differ fundamentally in design principle and in practicality.Such difference comes to a head in the event of integrator windup:while reset windup is a problem of actuator saturation,the integrator windup is a runaway situation due to controller instability.In fact,there is no advantage gained in replacing MR with an integrator.In other words,one should not integrate the error directly as in standard PID,since doing so makes the closed-loop system internally unstable.With MR-based control formulated in this paper,there is no such threat of instability and,therefore,no need for any anti-windup mechanisms.Furthermore,the integral control is made scalable in this framework as a tradeoff between the steady-state accuracy and the controller stability.This leads to a novel MR-based control design,scalable in gain and in time to accommodate various process characteristics and design specifications.Simple in construction and transparent in principle,this MR-based control,as a basic framework of design,is readily deployable in scale.
基金supported by the National Natural Science Foundation of China(project No 51872298)the fund of the State Key Laboratory of Technologies in Space Cryogenic Pro-pellants(project No SKLTSCP202202)the Strategic Priority Research Program of the Chinese Academy of Science(project No XDA22010202).
文摘Multiscale shell structure design is a rational and promising way to regulate the performance of hollow spheres in terms of both functionality and structural robustness,but it remains a big challenge to realize micro-nano engineering of the thin shell while maintaining the low density.In this work,the divisional shell design strategy was adopted to obtain the glass-cobalt-cobalt sulfide composite hollow microspheres(CSH),and an unprecedented stepwise high-temperature chemical reaction-induced aggregation and sub-sequent volume expansion strategy was developed to achieve rational regulation of core-shell structured cobalt-cobalt sulfide building units(BU)assembled on hollow glass microspheres.Special attention has been paid to the sulfidation degree-induced volume control with the underlying mechanism of volume expansion during chemical conversion from metallic cobalt to cobalt sulfide.The electromagnetic prop-erty was found to depend largely on the sulfidation degree due to the volume expansion-induced inter-connecting status regulation among the BU.When evaluated as microwave absorbent,an optimized broad bandwidth of 5.12 GHz and a minimum reflection loss(RLmin)of-45.58 dB of our CSH can be achieved at a thin matching thickness of 1.67 mm and a low filling ratio of 20.04 wt%.In addition to functionality,the divisional shell design also brings the CSH high structural strength(92.36%survival rate at a high hydrostatic pressure of 20 MPa)at low density(0.73 g cm^(-3)).
基金the National Natural Science Foundation of China(Nos.52475301,52005222,and 12272151)Open Fund for Key Laboratory of Bionic Engineering(Ministry of Education)of Jilin University(K202207)。
文摘The indiscriminate discharge of industrial wastewater and oil leakage accidents cause serious water pollution and pose threats to aquatic ecosystems and sanitary environments.The oily wastewater system is complex and most membrane materials cannot separate various oil-water mixtures.S erious membrane pollution would cause a decrease in separation flux.We proposed a pre-identified organic hydrogel surface prepared by micro-nano manufacturing technology for selective oil/water separation with ultra-high separating flux.Stimulated by water,the prepared surface is superhydrophilic-underwater superoleophobic,allowing water to pass through,and stimulated by oil,the prepared surface is superoleophilic-underoil superhydrophobic,allowing oil to pass through.Thus,based on the special solvent-responsive property,the prepared surface has a pre-identified function for water and oil,and could achieve the capture of oil droplets in water and water droplets in oil.In addition,the surface maintains an ultra-high separating efficiency and flux of about 99.85%and 17750 L·m^(-2)·h^(-1),and even after continuous cycles without cleaning,it could keep 99.1%and 16000 L·m^(-2)·h^(-1)due to the excellent anti-fouling ability.This study provides new ideas and methods for designing intelligent oil-water separation devices,and further guidance for achieving on-demand oily wastewater treatment.
基金supported by the National Natural Science Foundation of China(No.62241109)the Tianjin Science and Technology Commissioner Project(No.20YDTPJC01110)。
文摘An improved model based on you only look once version 8(YOLOv8)is proposed to solve the problem of low detection accuracy due to the diversity of object sizes in optical remote sensing images.Firstly,the feature pyramid network(FPN)structure of the original YOLOv8 mode is replaced by the generalized-FPN(GFPN)structure in GiraffeDet to realize the"cross-layer"and"cross-scale"adaptive feature fusion,to enrich the semantic information and spatial information on the feature map to improve the target detection ability of the model.Secondly,a pyramid-pool module of multi atrous spatial pyramid pooling(MASPP)is designed by using the idea of atrous convolution and feature pyramid structure to extract multi-scale features,so as to improve the processing ability of the model for multi-scale objects.The experimental results show that the detection accuracy of the improved YOLOv8 model on DIOR dataset is 92%and mean average precision(mAP)is 87.9%,respectively 3.5%and 1.7%higher than those of the original model.It is proved the detection and classification ability of the proposed model on multi-dimensional optical remote sensing target has been improved.
基金supported by the National Natural Science Foundation of China(No.82371530,82171529)the Capital Health Development Special Research Project(2022-1-4111)the National Key Technology R and D Program(No.2015BAI13B01).
文摘Background The patient-reported Dimensional Anhedonia Rating Scale(DARS)has been adapted into Chinese,so there is a need to evaluate its measurement properties in a Chinese population.Aims To evaluate the reliability and validity of the DARS among Chinese individuals with major depressive disorder(MDD)and its treatment sensitivity in a prospective clinical study.Methods Data were from a multicentre,prospective clinical study(NCT03294525),which recruited both patients with MDD,who were followed for 8 weeks,and healthy controls(HCs),assessed at baseline only.The analysis included confirmatory factor analysis,validity and sensitivity to change.Results Patients’mean(standard deviation(SD))age was 34.8(11.0)years,with 68.7%being female.75.2%of patients with MDD had melancholic features,followed by 63.8%with anxious distress.Patients had experienced MDD for a mean(SD)of 9.2(18)months.DARS scores covered the full range of severity with no major floor or ceiling effects.Confirmatory factor analysis showed adequate fit statistics(comparative fit index 0.976,goodness-of-fit index 0.935 and root mean square error of approximation 0.055).Convergent validity with anhedonia-related measures was confirmed.While the correlation between the DARS and the Hamilton Depression Rating Scale was not strong(r=0.31,baseline),the DARS was found to differentiate between levels of depression.Greater improvements in DARS scores were seen with the Hamilton Rating Scale for Depression responder group(effect size 1.16)compared with the non-responder group(effect size 0.46).Conclusions This study comprehensively evaluated the measurement properties of the DARS using a Chinese population with MDD.Overall,the Chinese version of DARS demonstrates good psychometric properties and has been found to be responsive to change during antidepressant treatment.The DARS is a suitable scale for assessing patient-reported anhedonia in future clinical trials.
基金supported by the Turkish Green Crescent Society under Grant[41402653-160-6/333].
文摘Background The effectiveness of life skills-based prevention programs to prevent substance addiction has been underexplored in Türkiye,likely in part due to the lack of validated measurement tools developed specifically for that purpose.Therefore,the aim of this study is to develop a tool to measure life skills for middle school students.The present study aims to test the factorial structure,reliability,convergent and discriminant validity,and measurement invariance across gender and age groups of the Green Crescent Life Skills(GCLS)Scale.Methods The study was conducted in Istanbul with two different sample groups.The first sample consisted of 566 and the second sample consisted of 885 middle school students.In the study,exploratory factor analysis(EFA)was applied to the first sample,and confirmatory factor analysis(CFA)was applied to the second sample to test the factorial structure of the scale.Convergent and discriminant validity were examined to provide evidence for construct-based validity.The reliability of the scale was assessed with Cronbach’sα,composite reliability,McDonald’sω,and test-retest.Results The EFA results showed that the scale consisted of four factors(self-awareness,coping with negative emotions,thinking skills,and peer relations).CFA results also confirmed this structure.The results revealed a significant positive correlation(r=0.52,p<0.01)between life skills and avoidance self-efficacy scores,as well as a significant negative correlation(r=−0.53,p<0.01)between life skills and attitude toward drug use scores.Additionally,it was found that measurement invariances based on gender and age groups were provided.It was determined that all sub-dimensions had sufficient reliability levels.Conclusion The findings of this validation study show that the GCLS Scale,which assesses four skills in a self-reported format,is a valid and reliable scale with considerable potential utility in monitoring life skills in Turkish adolescent populations.
基金funded by the National Natural Science Foundation of China(Grant No.52276047)the Open Fund of NationalKey Laboratory of SpacecraftThermal Control(Grant No.NKLST-JJ-202401011)the Beijing Municipal Science&Technology Commission(Grant No.Z231100006123010).
文摘Flow boiling in open microchannels offers highly efficient heat transfer performance and has attracted increasing attention in the fields of heat transfer and thermalmanagement of electronic devices in recent years.However,the continuous rise in power density of electronic components imposesmore stringent requirements on the heat transfer capability of microchannel flow boiling.HFE-7100,a dielectric coolant with favorable thermophysical properties,has become a focal point of research for enhancing flow boiling performance in open microchannels.The flow boiling heat transfer performance ofHFE-7100 was investigated in this study by fabricating micro-nano composite structures on the bottom surface of open microchannels using laser ablation technology.Based on visualization results,a comparative analysis was conducted on the bubble dynamics and flow pattern characteristics of HFE-7100 flow boiling in micronano structured open microchannels(MNSOMC)and smooth-surface open microchannels(SSOMC),to elucidate the enhancement mechanism of micro-nano structures on flow boiling heat transfer in open microchannels.The results indicate that the surface structures and strong wettability of MNSOMC accelerated bubble nucleation and departure.Moreover,bubbles in the channel tended to coalesce along the flow direction,forming elongated slug bubbles with high aspect ratios,which enabled efficient thin film evaporation in conjunction with intense nucleate boiling,thereby significantly enhancing flow boiling heat transfer.Under the experimental conditions of this study,the maximum enhancements in the heat transfer coefficient(HTC)and critical heat flux(CHF)of HFE-7100 inMNSOMC were 33.4%and 133.1%,respectively,with the CHF reaching up to 1542.3 kW⋅m^(−2).Furthermore,due to the superior wettability and capillary wicking capability of the micro-nano composite structures,the significant enhancement in flow boiling heat transfer was achieved without incurring a noticeable pressure drop penalty.
基金supported by the National Natural Science Foundation of China(No.62101587)the National Funded Postdoctoral Researcher Program of China(No.GZC20233578)。
文摘Micro-nano Earth Observation Satellite(MEOS)constellation has the advantages of low construction cost,short revisit cycle,and high functional density,which is considered a promising solution for serving rapidly growing observation demands.The observation Scheduling Problem in the MEOS constellation(MEOSSP)is a challenging issue due to the large number of satellites and tasks,as well as complex observation constraints.To address the large-scale and complicated MEOSSP,we develop a Two-Stage Scheduling Algorithm based on the Pointer Network with Attention mechanism(TSSA-PNA).In TSSA-PNA,the MEOS observation scheduling is decomposed into a task allocation stage and a single-MEOS scheduling stage.In the task allocation stage,an adaptive task allocation algorithm with four problem-specific allocation operators is proposed to reallocate the unscheduled tasks to new MEOSs.Regarding the single-MEOS scheduling stage,we design a pointer network based on the encoder-decoder architecture to learn the optimal singleMEOS scheduling solution and introduce the attention mechanism into the encoder to improve the learning efficiency.The Pointer Network with Attention mechanism(PNA)can generate the single-MEOS scheduling solution quickly in an end-to-end manner.These two decomposed stages are performed iteratively to search for the solution with high profit.A greedy local search algorithm is developed to improve the profits further.The performance of the PNA and TSSA-PNA on singleMEOS and multi-MEOS scheduling problems are evaluated in the experiments.The experimental results demonstrate that PNA can obtain the approximate solution for the single-MEOS scheduling problem in a short time.Besides,the TSSA-PNA can achieve higher observation profits than the existing scheduling algorithms within the acceptable computational time for the large-scale MEOS scheduling problem.
文摘Loneliness is a complex and usually unpleasant emotional response to isolation,which has been considered the latest global health epidemic exacerbated by the coronavirus disease 2019 pandemic,affecting nearly twothirds of older adults.Some profound health implications carried by loneliness include depression,cognitive impairment,hypertension and frailty.Across the world,there is no consensus definition of loneliness,and its measure is based on the phenomenological perspective of the individual.The 20-item University of California Los Angeles Loneliness Scale version 3(UCLA-20)is the most common measure.This scale demonstrates acceptable psychometric properties but is too long and complex for a phone interview.This paper addresses the increasing need to shorten this scale by adopting classical item response theory and network psychometrics to advance scale development.Through an item reduction analysis,we trimmed the original scale into an effective short form,which is as valid as the original one.With respondents’time at a premium in most research nowadays,this shortform scale is an efficient and practical alternative to the original UCLA-20.
文摘BACKGROUND During the gradual decline of physical and social functioning associated with end-stage renal disease,patients might experience a premonition of impending death,resulting in a series of pre-mourning grief responses called preparatory grief.The preparatory grief in advanced cancer patients(PGAC)scale is the most widely used preparatory grief scale for patients on hemodialysis in China.AIM To verify the reliability and validity of the PGAC scale in patients on hemodialysis.METHODS In total,327 patients undergoing regular hemodialysis in the blood purification center of three grade-A tertiary hospitals in Guangdong and Guizhou provinces were selected by convenience sampling.The assessment was administered using the general information questionnaire and the Chinese version of PGAC.SPSS 25.0 and Amos 24.0 were used for item analysis,confirmatory factor analysis(CFA),convergent validity,and internal consistency reliability estimation.RESULTS In the modified Chinese version of PGAC,7 dimensions covering 27 total items were retained.CFA revealed a good fit of the factor model(chi-square degree of freedom=2.056,standardized root mean square residual=0.0479,root mean square error of approximation=0.0570,GFI=0.872,AGFI=0.841,IFI=0.931,CFI=0.930,TLI=0.919).The factor loadings of the items ranged 0.503-0.884.The composite reliability ranged 0.664-0.914,and the average variance extracted ranged 0.366-0.747.Cronbach’sαof the scale was 0.945,and Cronbach’sαfor various dimensions ranged 0.662-0.914.CONCLUSION The modified PGAC has good reliability and validity,and it can effectively measure preparatory grief in patients on hemodialysis.
