期刊文献+
共找到346,486篇文章
< 1 2 250 >
每页显示 20 50 100
Growth pattern of MAO coating under constant voltage–current two-step power mode 被引量:1
1
作者 Shu-fan Zhou Liang-yu Chen +5 位作者 Wei-gang Lv Jun-jie Gu Fei Ye Dubovyy Oleksandr Sheng Lu Ze-xin Wang 《Journal of Iron and Steel Research International》 2025年第5期1245-1262,共18页
A custom micro-arc oxidation(MAO)apparatus is employed to produce coatings under optimized constant voltage–current two-step power supply mode.Various analytical techniques,including scanning electron microscopy,conf... A custom micro-arc oxidation(MAO)apparatus is employed to produce coatings under optimized constant voltage–current two-step power supply mode.Various analytical techniques,including scanning electron microscopy,confocal laser microscopy,X-ray diffraction,X-ray photoelectron spectroscopy,transmission electron microscopy,and electrochemical analysis,are employed to characterize MAO coatings at different stages of preparation.MAO has MgO,hydroxyapatite,Ca_(3)(PO_(4))_(2),and Mg2SiO4 phases.Its microstructure of the coating is characterized by"multiple breakdowns,pores within pores",and"repaired blind pores".The porosity and the uniformity of MAO coating first declines in the constant voltage mode,then augments while the discharge phenomenon takes place,and finally decreases in the repair stage.These analyses reveal a four-stage growth pattern for MAO coatings:anodic oxidation stage,micro-arc oxidation stage,breakdown stage,and repairing stage.During anodic oxidation and MAO stages,inward growth prevails,while the breakdown stage sees outward and accelerated growth.Simultaneous inward and outward growth in the repair stage results in a denser,more uniform coating with increased thickness and improved corrosion resistance. 展开更多
关键词 Micro-arc oxidation Biomedical material Corrosion resistance growth pattern Two-step power mode
原文传递
Research on the Growth Patterns and Training Paths of Excellent Counselors in Private Colleges
2
作者 Jian Du 《Journal of Contemporary Educational Research》 2025年第4期184-192,共9页
With the rapid development of private higher education,the construction of counselor teams in private universities has become increasingly important.This paper focuses on outstanding counselors in private universities... With the rapid development of private higher education,the construction of counselor teams in private universities has become increasingly important.This paper focuses on outstanding counselors in private universities,delving into their growth patterns and proposing targeted training paths based on this analysis.By reviewing relevant theories and analyzing case studies of excellent counselors,it is found that outstanding counselors in private universities exhibit stage-specific characteristics during their development,influenced by personal traits,school environment,career progression,and other factors.In terms of training approaches,efforts should be made to improve selection mechanisms,strengthen training systems,provide career development support,and create a positive work atmosphere,all aimed at enhancing the overall quality of the counselor team in private universities and better serving student growth and institutional development. 展开更多
关键词 Private colleges and universities COUNSELORS growth patterns Training paths
在线阅读 下载PDF
基于FP-Growth算法和贝叶斯模型的坍塌事故致因分析
3
作者 李珏 曾敏 《武汉理工大学学报(信息与管理工程版)》 2026年第1期15-21,共7页
为探究建筑施工安全风险,深入分析建筑工程中的坍塌事故风险,通过改进的人因分析和分类系统(HFACS)模型识别出32个坍塌事故的关键致因。同时为深入挖掘事故特征,明确施工坍塌事故的成因机制,采用基于FP-Growth算法的关联规则挖掘方法构... 为探究建筑施工安全风险,深入分析建筑工程中的坍塌事故风险,通过改进的人因分析和分类系统(HFACS)模型识别出32个坍塌事故的关键致因。同时为深入挖掘事故特征,明确施工坍塌事故的成因机制,采用基于FP-Growth算法的关联规则挖掘方法构建贝叶斯网络结构,通过数据驱动的方式训练模型,从而提升坍塌事故推理分析的效率与精度。基于贝叶斯网络的敏感性分析与逆向推理,识别出5类坍塌事故的关键致因及其致因路径。研究结果表明:土方坍塌、建筑物坍塌、拆除工程坍塌和模板坍塌多由不安全行为前提条件造成,脚手架坍塌多由不安全行为前提条件和不安全行为共同造成。通过关键致因链分析可知5类坍塌事故的发生路径,从而对各类事故进行管控。 展开更多
关键词 FP-growth算法 贝叶斯网络 HFACS模型 风险分析 关联规则
在线阅读 下载PDF
Comparing ecological memory effects of the bimodal radial growth in the Qinling Mountains and Mediterranean forests
4
作者 Huiyue Yan Xiaomin Zeng +4 位作者 Xiaohong Liu Yu Xue Quanxi Li Lingnan Zhang Jun Liu 《Forest Ecosystems》 2026年第1期131-143,共13页
Intra-annual climatic variability plays a critical role in regulating wood formation dynamics during the growing season,particularly in seasonally arid regions—such as the Qinling Mountains,China,and Mediterranean fo... Intra-annual climatic variability plays a critical role in regulating wood formation dynamics during the growing season,particularly in seasonally arid regions—such as the Qinling Mountains,China,and Mediterranean forests—where trees exhibit bimodal radial growth patterns as an adaptive response to water stress.While these growth patterns reflect immediate climatic conditions,the role of ecological memory,specifically vegetation growth carryover(VGC)and lagged climate effects(LCEs),remains poorly quantified.We employed the Vaganov–Shashkin(VS)model to analyze intra-annual bimodal growth patterns in two regions and used a vector autoregressive model with impulse response functions to assess the duration and intensity of VGC and LCE on tree-ring growth and remote sensing vegetation indices(leaf area index(LAI)and gross primary productivity(GPP)).Our results revealed bimodal growth patterns with spring and autumn peaks,but the autumn peak occurred earlier in the Qinling Mountains(August–October)than in Mediterranean forests(late September–October).VGC exerted the strongest influence on tree-ring growth in the first year,diminishing significantly after eight years in both regions(p<0.01).Tree-ring growth exhibited positive LCE responses to precipitation and soil moisture but negative responses to temperature(p<0.05).Remote sensing indices(LAI and GPP)displayed stronger VGC effects in the Qinling Mountains than in Mediterranean forests.While both LAI and GPP responded positively to soil moisture,temperature-induced LCE was positive in the Qinling Mountains but negative in the Mediterranean forests(p<0.05).Overall,VGC was the dominant ecological memory effect in both regions.Our results suggest that coupling the VGC and LCE of multiple vegetation growth indicators at multiple scales has the potential to improve the accuracy of global dynamic vegetation models. 展开更多
关键词 Tree-ring width Bimodal growth patterns Vaganov-Shashkin(VS)model Vegetation growth carryover Lagged climate effects(LCEs)
在线阅读 下载PDF
Effects of Microplastics on Growth Pattern of Pinus massoniana and Schima uperba
5
作者 Keke Zhang Yong Cui +6 位作者 Changchang Shao Liqing Yang Yuxin Wang Yao Fang Hua Zhou Jie Wang Honglang Duan 《Phyton-International Journal of Experimental Botany》 2025年第9期2855-2871,共17页
As ubiquitous environmental contaminants,microplastics(MPs)have garnered global concern due to their persistence,bioaccumulation potential,and multifaceted threats to ecosystem health.These particles threaten terrestr... As ubiquitous environmental contaminants,microplastics(MPs)have garnered global concern due to their persistence,bioaccumulation potential,and multifaceted threats to ecosystem health.These particles threaten terrestrial ecosystems via soil contamination;however,research on their phytotoxicity remains predominantly focused on herbaceous plants.The responses of woody plants to MPs and their interspecific differences are severely unexplored.Here,two important ecological and economical tree species in southern China,Pinus massoniana(P.massoniana)and Schima superba(S.superba),were selected to explore the ecotoxicity effects of polyethylene(PE)and polypropylene(PP)MPs(the two most abundant species in the soil)on seedling growth characteristics,specific leaf area(SLA)and biomass allocation at 0%,1%,5%and 10%concentration gradients in the 120-day potted experiment.The results showed that the inhibition effect of MPs was concentration and tree species-dependent.Seedling height,basal diameter,and total biomass of P.massoniana decreased significantly with increased concentration,while S.superba showed a non-significant growth effect at 1%concentration.The SLA was generally increased,revealing that plants enhanced their light capture ability through leaf morphological plasticity to compensate for the loss of carbon assimilation.There were interspecific differences in root investment strategies:the root-shoot ratio of P.massoniana was significantly reduced by 48.43%under 10%PP treatment.In comparison,the root-shoot ratio of S.superba was significantly reduced by maintaining a higher root-shoot ratio(65.26%higher than that of P.massoniana on average)and phased resource allocation(5%concentration biomass is higher than 10%)partially alleviated the toxic pressure.Collectively,our results indicate that the ecotoxicity of MPs was mainly driven by concentration and was not correlated with type(PE/PP),while the differences in tree species response were closely related to their resource allocation strategies and morphological plasticity.These findings imply that MPs contamination can differently impact the growth and development of dominant tree species,potentially altering the structure,diversity,and function of forest ecosystems.This study systematically revealed the growth response mechanism of native common tree species to MPs pollution and provided a theoretical basis for sustainable management of plantations and toxicological risk assessment of forest ecosystems. 展开更多
关键词 Microplastics growth biomass allocation SPECIES-SPECIFIC
在线阅读 下载PDF
Frequent Pattern Growth-Based Identification of Critical Lines in Cascading Failures for Renewable-Dominant Hybrid AC/DC Power Systems
6
作者 Tianhao Liu Jiongcheng Yan Yutian Liu 《Engineering》 2025年第8期158-170,共13页
In wind and solar renewable-dominant hybrid alternating current/direct current(AC/DC)power systems,the active power of high-voltage direct current(HVDC)system is significantly limited by the security and stability eve... In wind and solar renewable-dominant hybrid alternating current/direct current(AC/DC)power systems,the active power of high-voltage direct current(HVDC)system is significantly limited by the security and stability events caused by cascading failures.To identify critical lines in cascading failures,a rapid risk assessment method is proposed based on the gradient boosting decision tree(GBDT)and frequent pat-tern growth(FP-Growth)algorithms.First,security and stability events triggered by cascading failures are analyzed to explain the impact of cascading failures on the maximum DC power.Then,a cascading failure risk index is defined,focusing on the DC power being limited.To handle the strong nonlinear relationship between the maximum DC power and cascading failures,a GBDT with an update strategy is utilized to rapidly predict the maximum DC power under uncertain operating conditions.Finally,the FP-Growth algorithm is improved to mine frequent patterns in cascading failures.The importance index for each fault in a frequent pattern is defined by evaluating its impact on cascading failures,enabling the identification of critical lines.Simulation results of a modified Ningxia–Shandong hybrid AC/DC system in China demonstrate that the proposed method can rapidly assess the risk of cascading failures and effectively identify critical lines. 展开更多
关键词 Cascading failure Risk assessment Frequent pattern Hybrid AC/DC power system Renewable energy
在线阅读 下载PDF
Spatiotemporal patterns and driving factors for vegetation growth status in the upper reaches of the Yellow River
7
作者 Xiaolong Wang Yongde Gan +5 位作者 Yangwen Jia Ziqi Su Jianhua Wang Chenhui Ma Zhaolin Zhang Huan Liu 《River》 2025年第3期311-329,共19页
The impact of climate change on vegetation ecosystems is a prominent focus in global climate change research.The climate change affects vegetation growth and ecosystem stability in the upper reaches of the Yellow Rive... The impact of climate change on vegetation ecosystems is a prominent focus in global climate change research.The climate change affects vegetation growth and ecosystem stability in the upper reaches of the Yellow River(UYR).However,the spatiotemporal patterns and driving mechanisms of vegetation growth status(VGS)in the region remain poorly understood.Based on the hydrological model PLS,an innovative WEP-CHC model was developed by integrating regional environmental and vegetation growth characteristics.Furthermore,combined with the PLS-SEM model and other methods,this study systematically investigated the spatiotemporal patterns and driving mechanisms of VGS in the UYR.The results indicated that:①VGS exhibited significant spatiotemporal variation trends within the study area.In the study period of 1970–2020,the GPP onset time was significantly advanced(p<0.05)while the GPP peak value was significantly increased.Spatial analysis revealed significant spatial complexity in the GPP onset time and peak values across the region.②Soil freeze-thaw conditions significantly influenced VGS(p<0.05).The complete thawing time of permafrost was closely coincided with the GPP onset time,with a correlation coefficient exceeding 0.84.After controlling soil freeze-thaw effects using partial correlation analysis,it was found that better initial soil hydrothermal conditions would lead to better VGS;③The model constructed with annual hydrothermal conditions(AHC),soil freeze-thaw period(SFTP),vegetation growth season(VGS),initial soil hydrothermal conditions(ISHC),and annual solar radiation conditions(ASRC),demonstrated good explanatory power for vegetation growth.The R^(2)values of PLS-SEM were above 0.76 in all five subregions.However,their effects on VGS varied significantly across subregions.Overall,AHC and SFTP were the dominant factors in all subregions.Furthermore,the impacts of ISHC and VGC were statistically insignificant,whereas the effects of ASRC exhibited high complexity.This study not only provides new insights into the current state of hydrological-ecological coupling in the UYR but also offers a new tool for ecological conservation and sustainable water management in other cold regions and similar watersheds worldwide. 展开更多
关键词 driving factors ecological hydrological model GPP spatiotemporal variation vegetation growth status
在线阅读 下载PDF
Analysis of height and diameter growth patterns in Sakhalin fir seedlings competing with evergreen dwarf bamboo and deciduous vegetation using generalized additive models
8
作者 Hisanori Harayama Takeshi Yamada +1 位作者 Mitsutoshi Kitao Ikutaro Tsuyama 《Journal of Forestry Research》 2025年第5期76-89,共14页
The growth of Sakhalin fir(Abies sachalinen-sis)seedlings,an important forest tree species in northern Hokkaido,Japan,is significantly affected by competition from surrounding vegetation,especially evergreen dwarf bam... The growth of Sakhalin fir(Abies sachalinen-sis)seedlings,an important forest tree species in northern Hokkaido,Japan,is significantly affected by competition from surrounding vegetation,especially evergreen dwarf bamboo.In this study,we investigated the height and root collar diameter(RCD)growth of Sakhalin fir seedlings under various degrees of cover by deciduous vegetation and evergreen dwarf bamboo.Generalized additive models were used to quantify the effects of canopy cover and forest floor cover on the relative growth rates of these two parameters.The canopy cover of Sakhalin fir seedlings had a nonlin-ear negative effect on both the height growth of seedlings in the subsequent year and the RCD growth in the current year,given the general growth pattern in this species,where height growth ceases in early summer and RCD growth con-tinues until autumn.Height growth declined sharply after the canopy cover rate exceeded 50%,while RCD growth declined rapidly between 0 and 50%canopy cover rate.The forest floor cover had a greater negative impact on RCD growth than on height growth.These results suggested that Sakhalin fir seedlings respond to vegetative competition by prioritizing height growth for light acquisition at the expense of diameter growth and possibly root growth for below-ground competition.The cover of evergreen dwarf bamboo reduced the height growth of fir seedlings significantly more than the cover of deciduous vegetation.This difference is likely due to the timing of light availability.When competing with deciduous vegetation,Sakhalin fir seedlings exposed to light during the post-snow melt and early spring before the development of the deciduous vegetation canopy can photosynthesize more effectively,leading to greater height growth.The results of this study highlighted the importance of vegetation control considering the type of vegetation for successful Sakhalin fir reforestation.Adjusting the intensity and timing of weeding based on the presence and abundance of dwarf bamboo and other competing vegetation could potentially reduce weeding costs and increase biodiversity in reforested areas. 展开更多
关键词 Abies sachalinensis Competition Crown cover Forest floor cover Generalized additive models(GAM) Relative growth rate
在线阅读 下载PDF
Seasonal emission patterns of airborne phytoncides in temperate forests from autumn to early spring:a case study of Xishui National Forest Park(Yichun,Northeast China)
9
作者 Hongda Cai Yitong Wang +6 位作者 Xianwen Huang Sen Zhang Yankun Liu Jian Zhang Dongmei Zhao Peng Zhao Xiuhua Zhao 《Journal of Forestry Research》 2026年第1期256-271,共16页
Xishui National Forest Park in Heilongjiang Province hosts China's most pristine temperate forests and serves as a key site for ecotourism and forest therapy.However,the emission patterns of phytoncides(key bio ac... Xishui National Forest Park in Heilongjiang Province hosts China's most pristine temperate forests and serves as a key site for ecotourism and forest therapy.However,the emission patterns of phytoncides(key bio active compounds) remain poorly understood,limiting their therapeutic application.This study provides the first comprehensive characterization of spatiotemporal dynamics in airborne phytoncides and their synergistic interactions with environmental factors throughout the autumn-early spring seasonal transition in a temperate forest ecosystem.We analyzed the compositional dynamics of phytoncides and terpenoid content variations using thermal desorption-gas chromatography-mass spectrometry(TD-GC-MS) from September 2024 to March 2025.This period encompassed seasonal transitions from autumn to early spring,including diurnal variations in September and snowfall events in November.The method demonstrated detection limits(LODs) ranging from 1.35 to 5.33 ng m-3 and quantification limits(LOQs) from 4.09 to 16.15 ng m-3.Our results revealed pronounced seasonal fluctuations in phytoncide composition.In September,terpenoids,esters,alcohols,and alkanes displayed a diurnal "decrease-increase" trend,whereas aldehydes and ketones peaked at midday.Notably,esters and alcohols were undetectable in November and January.By January,terpenoids reached their lowest proportion(0.17±0.02%) at noon.Five terpenoids(α-pinene,myrcene,D-limonene,camphene,p-cymene) were detected in September,four(α-pinene,D-limonene,camphene,p-cymene) in November,two(D-limonene,p-cymene) in January,and only p-cymene in March.The total concentration and emission rate of the five terpenoids peaked in September afternoons at 1961.58±106.67 ng m^(-3) and653.86±35.56 ng m^(-3) h^(-1),respectively.Nocturnal emissions(32131.95±2522.21 ng m^(-3)) significantly surpassed daytime levels(14473.04±958.49 ng m^(-3)),with emission rates escalating from 1447.30±95.85 ng m^(-3) h^(-1)(day) to 5355.33±420.37 ng m^(-3) h^(-1)(night),marking a3.7-fold increase.Snowfall dramatically elevated terpenoid concentrations(pre-snowfall:158.58±14.12 ng m^(-3);post-snowfall:1080.57±57.76 ng m^(-3)) and emission rates(pre-snowfall:52.86±4.71 ng m^(-3) h^(-1);post-snowfall:360.19±19.25 ng m^(-3) h^(-1)),reflecting a 6.8-fold surge.This study underscores the profound influence of light intensity,seasonal shifts,and climatic conditions on airborne phytoncide levels,offering a scientific foundation for optimizing forest therapy and ecotourism strategies. 展开更多
关键词 Phytoncides Seasonal variation Diurnal-nocturnal patterns Snowfall impact Emission patterns
在线阅读 下载PDF
Light Regulation across Strawberry Growth Stages:A Comprehensive Review
10
作者 Geng Zhang Xiangyu Ding +7 位作者 Zidan Wen Chao Liu Duyen T.P.Nguyen Jinxiu Song Zejin Zhang Zhiming Yan Yuanhua Wang Zhengnan Yan 《Phyton-International Journal of Experimental Botany》 2026年第2期1-21,共21页
As a pivotal environmental factor,light,comprising intensity,photoperiod,and spectrum,governs the entire life cycle of strawberries by mediating alterations in the plant’s morphological,physiological,and biochemical ... As a pivotal environmental factor,light,comprising intensity,photoperiod,and spectrum,governs the entire life cycle of strawberries by mediating alterations in the plant’s morphological,physiological,and biochemical traits.Although extensive research has been conducted on light-mediated growth regulation in horticultural crops,most reviews focus primarily on leafy and fruiting vegetables,with limited attention given to berry crops such as strawberries.Additionally,most existing reviews concentrate on one or several growth stages,failing to systematically characterize light’s effects throughout the entire growth cycle and postharvest stage.This review briefly summarizes the regulatory roles of light across key stages of strawberry growth,including seedling propagation,vegetative growth,reproductive growth,and postharvest stages.It seeks to address the knowledge gap by systematically organizing research findings across these developmental phases.The integrated analysis provides a theoretical foundation for designing stage-specific lighting strategies to improve strawberry yield and quality. 展开更多
关键词 Light intensity light spectrum STRAWBERRY seedling propagation vegetative growth reproductive growth POSTHARVEST
在线阅读 下载PDF
Discrepancies between predictions of mainstream empirical growth models and observed forest growth of Pinus radiata(D.Don)plantations in New Zealand
11
作者 Serajis Salekin Yvette Dickinson +5 位作者 Jo Liddell Christine Dodunski Priscilla Lad Steven Dovey Donald A.White David Pont 《Forest Ecosystems》 2026年第1期157-165,共9页
Pinus radiata(D.Don)dominates New Zealand's forestry industry,constituting 91%of plantations,and is among the world's most important plantation species.Given the socio-economic and environmental importance of ... Pinus radiata(D.Don)dominates New Zealand's forestry industry,constituting 91%of plantations,and is among the world's most important plantation species.Given the socio-economic and environmental importance of this species,it is important to have accurate and precise projections over time to make efficient decisions for forest management and greenfield investments in afforestation projects,especially for permanent carbon forests.Future projections of any natural resource systems rely on modeling;however,the acceleration of climate change makes future projections of yield less certain.These challenges also impact national expectations of the contribution planted forests will provide to address climate change and meet international commitments under the Paris Agreement.Using a large national-scale set of contemporary ground-measured data(2013–2023),this study investigates the performance of two growth models developed over 30 years ago that are widely used by NZ plantation growers:1)the Pumice Plateau Model 1988(PPM88)and 2)the 300-index(including a model variant of regional drift).Model simulations were made using the FORECASTER modeling suite with geographic boundaries to adjust for drift in space and time.Basal area(BA,m^(2)⋅ha^(-1))and volume(m^(3)⋅ha^(-1))were simulated,and standard errors and goodness-of-fit metrics calculated up to a typical rotation age of 30 years.Model residuals were then separated and analysed for the main plantation growing regions.The models overpredicted observed growth by between 6.8%and 16.2%,but model predictions and errors varied significantly between regions.The results of this study provided clear evidence of divergence between the outputs of both models and the measured data.Finally,this study suggests future measures to address challenges posed by these discrepancies that will provide better information for forest management and investment decisions in a changing climate. 展开更多
关键词 Pinus radiata growth and yield prediction Empirical growth models Plantation forest Permanent sample plots Prediction errors Climate changeA
在线阅读 下载PDF
Improving Online Restore Performance of Backup Storage via Historical File Access Pattern
12
作者 Ruidong Chen Guopeng Wang +5 位作者 Jingyuan Yang Ziyu Wang Fang Zou Jia Sun Xingpeng Tang Ting Chen 《Computers, Materials & Continua》 2026年第3期1536-1558,共23页
The performance of data restore is one of the key indicators of user experience for backup storage systems.Compared to the traditional offline restore process,online restore reduces downtime during backup restoration,... The performance of data restore is one of the key indicators of user experience for backup storage systems.Compared to the traditional offline restore process,online restore reduces downtime during backup restoration,allowing users to operate on already restored files while other files are still being restored.This approach improves availability during restoration tasks but suffers from a critical limitation:inconsistencies between the access sequence and the restore sequence.In many cases,the file a user needs to access at a given moment may not yet be restored,resulting in significant delays and poor user experience.To this end,we present Histore,which builds on the user’s historical access sequence to schedule the restore sequence,in order to reduce users’access delayed time.Histore includes three restore approaches:(i)the frequency-based approach,which restores files based on historical file access frequencies and prioritizes ensuring the availability of frequently accessed files;(ii)the graph-based approach,which preferentially restores the frequently accessed files as well as their correlated files based on historical access patterns,and(iii)the trie-based approach,which restores particular files based on both users’real-time and historical access patterns to deduce and restore the files to be accessed in the near future.We implement a prototype of Histore and evaluate its performance from multiple perspectives.Trace-driven experiments on two datasets show that Histore significantly reduces users’delay time by 4-700×with only 1.0%-14.5%additional performance overhead. 展开更多
关键词 Online restore access pattern correlation graph TRIE
在线阅读 下载PDF
Effect of Cyclic Heat Treatment on Fatigue Crack Growth Rate of Ti-6Al-4V-1Mo Alloy Prepared by Laser Directed Energy Deposition
13
作者 Xue Lipan Zhang Fengying +6 位作者 Deng Yulin Ye Zimeng Zhao Kexin Yu Zerong Wu Wenlu Su Wei Yang Renjie 《稀有金属材料与工程》 北大核心 2026年第2期292-301,共10页
The fatigue crack growth rate of a novel Ti-6Al-4V-1Mo titanium alloy,which is developed for laser directed energy deposition technique,was investigated before and after cyclic heat treatment(CHT).Changes in microstru... The fatigue crack growth rate of a novel Ti-6Al-4V-1Mo titanium alloy,which is developed for laser directed energy deposition technique,was investigated before and after cyclic heat treatment(CHT).Changes in microstructure,fracture surfaces,and crack growth paths were analyzed before and after CHT.Results indicate that in the stable crack growth region,the growth rates for the as-deposited and cyclic heat-treated specimens follow the relationships da/dN=1.8651×10^(−8)(ΔK)^(3.2271)and da/dN=1.4112×10^(−8)(ΔK)^(3.1125),respectively.Compared with that at the as-deposited state,the microstructure after CHT is transformed from a uniform basket-weave microstructure to a dual-phase microstructure consisting of near-sphericalαandβ-transformed matrix phases.The cyclic process also disrupts the continuity of the grain boundaryα(αGB)at the primaryβ-phase grain boundary.The coarsening of primaryαand the disruption ofαGB continuity are the primary factors to release stress concentration and promote crack deflection,thereby decreasing the fatigue crack growth rate.Additionally,the increased occurrence of crack branching,secondary cracking,and crack bridging in cyclic heat-treated specimens further reduces the crack driving force and slows the fatigue crack growth rate. 展开更多
关键词 Ti-6Al-4V-1Mo alloy CHT fatigue crack growth rate laser directed energy deposition
原文传递
Evolution of diamond film growth modes under varied plasma conditions:insights from optical emission spectroscopy
14
作者 Pengfei Qu Guangdi Zhou +2 位作者 Peng Jin Xu Han Zhanguo Wang 《Journal of Semiconductors》 2026年第1期91-97,共7页
The synthesis of high-quality heteroepitaxial diamond films on iridium composite substrates is a critical step toward advancing diamond for electronic and optical applications.Microwave plasma chemical vapor depositio... The synthesis of high-quality heteroepitaxial diamond films on iridium composite substrates is a critical step toward advancing diamond for electronic and optical applications.Microwave plasma chemical vapor deposition,combined with in situ optical emission spectroscopy,enables precise control over growth modes through plasma parameter tuning.In this study,we examine how methane concentration,microwave power,and gas pressure influence plasma species and,consequently,the growth modes of heteroepitaxial diamond by optical emission spectroscopy and scanning electron microscope.At low nucleation densities,increased methane concentrations promote the transition from faceted polyhedral to ballas structures,driven by elevated C_(2) radical concentrations in the plasma.Conversely,at higher nucleation densities,gas pressure,and substrate temperature dominate growth mode determination,leading to diverse morphologies,such as planar,polycrystalline,octahedral,and step-flow growth.These findings elucidate the interplay among plasma species,growth parameters,and growth mode,offering critical insights for optimizing growth conditions and preparing heteroepitaxial diamond films in a specific growth mode. 展开更多
关键词 HETEROEPITAXY diamond films growth modes MPCVD OES
在线阅读 下载PDF
Reproducible Fabrication of Perovskite Photovoltaics via Supramolecule Confinement Growth
15
作者 Xinyi Liu Jin Xie +11 位作者 Ziren Zhou Huijun Lian Xinyuan Sui Qing Li Miaoyu Lin Da Liu Haiyang Yuan Feng Gao Yongzhen Wu Hua Gui Yang Shuang Yang Yu Hou 《Nano-Micro Letters》 2026年第2期756-771,共16页
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
关键词 Solar cells REPRODUCIBILITY Perovskites Space-confined growth SUPRAMOLECULES
在线阅读 下载PDF
Vascular plant diversity and distribution pattern in Tajikistan:A global hotspot of diversity
16
作者 ZHOU Yixin MA Suliya +7 位作者 LI Wenjun Parvina KURBONOVA Mariyo BOBOEV LI Yufan Hikmat HISORIEV MA Keping YANG Weikang ZHANG Yuanming 《Regional Sustainability》 2026年第1期37-53,共17页
Tajikistan represents a core region of the biodiversity hotspot in Central Asian mountains and has exceptional vascular plant diversity.However,the species diversity of the country faces urgent conservation challenges... Tajikistan represents a core region of the biodiversity hotspot in Central Asian mountains and has exceptional vascular plant diversity.However,the species diversity of the country faces urgent conservation challenges.There has been a lack of a comprehensive and multidimensional assessment to inform strategic conservation planning.Therefore,this study integrated 4 key biodiversity indices including species richness(SR),phylogenetic diversity(PD),threatened species richness(TSR),and endemic species richness(ESR)to map species diversity distribution patterns,identify conservation gaps,and elucidate their effects of climatic factors.This study revealed that species diversity shows a clear trend of decreasing from the western region to the eastern region of Tajikistan.The central–western mountains(specifically the Gissar-Darvasian and Zeravshanian regions)emerge as irreplaceable biodiversity hotspots.However,we found a severe spatial mismatch between these priority areas and the existing protected areas(PAs).Protection coverage for all hotspots was alarmingly low,ranging from 31.00%to 38.00%.Consequently,a critical 64.80%of integrated priority areas fall outside of the current PAs,representing a major conservation gap.This study identified precipitation seasonality and isothermality as the principal drivers,collectively explaining over 50.00%of the diversity variation and suggesting high vulnerability to hydrological shifts.Furthermore,we detected significant geographic sampling bias in the public biodiversity databases,with the most critical hotspot being systematically under-sampled.This study provides a robust scientific basis for conservation action,highlighting the urgent need to strategically expand PAs in the under-protected southwestern region and to mitigate critical sampling gaps through targeted data digitization and field surveys.These measures are indispensable for securing Tajikistan’s unique biodiversity and achieving the Kunming-Montreal Global Biodiversity Framework Target 3(“30×30 Protection”). 展开更多
关键词 Vascular plant Species diversity Distribution pattern Conservation gaps TAJIKISTAN
在线阅读 下载PDF
Thermal stability design for flexural wave bandgap of metamaterial plates with perforated and pre-curved patterns
17
作者 Qian GENG Xing ZHOU +3 位作者 Mengyang WANG Xiongwei YANG Zhushan SHAO Yueming LI 《Applied Mathematics and Mechanics(English Edition)》 2026年第3期443-472,I0001-I0004,共34页
A design idea for single-component metamaterial plates is proposed to achieve the thermal stability of flexural wave bandgap by the perforated and pre-curved patterns.The band structure analysis suggests that perforat... A design idea for single-component metamaterial plates is proposed to achieve the thermal stability of flexural wave bandgap by the perforated and pre-curved patterns.The band structure analysis suggests that perforation can release part of the in-plane thermal expansion to weaken the softening effect of thermal stress.Introducing precurved components to the perforated structure will stop the decrement of the bandgap frequency in thermal environment,and even make the frequency higher with appropriate structural parameters.The bending stiffness of the heated plate is enhanced by the thermal deflection induced stiffening effect of the pre-curved components.The segmented pre-curved component presents a strong ability to resist the thermal influence on the flexural wave bandgap.A simplified model is established for the local structure of the precurved component.The theoretical calculations explain the thermally induced frequency increment of the bandgap and the discrepancy in the thermal response between the two pre-curved models.The transmittance of flexural wave validates the effectiveness of the proposed design. 展开更多
关键词 metamaterial plate flexural vibration bandgap PERFORATION pre-curved pattern thermal stability
在线阅读 下载PDF
Patterns of utilization of antipsychotic drugs and direct medical costs among patients with schizophrenia in a tertiary care hospital
18
作者 Aqeel Haider Lekha Saha Debashish Basu 《World Journal of Psychiatry》 2026年第1期125-135,共11页
BACKGROUND Drug utilization research has an important role in assisting the healthcare administration to know,compute,and refine the prescription whose principal objective is to enable the rational use of drugs.Resear... BACKGROUND Drug utilization research has an important role in assisting the healthcare administration to know,compute,and refine the prescription whose principal objective is to enable the rational use of drugs.Research in developing nations relating to the cost of treatment is scarce when compared with developed countries.Thus,the drug utilization research studies from developing nations are most needed,and their number has been growing.AIM To evaluate patterns of utilization of antipsychotic drugs and direct medical cost analysis in patients newly diagnosed with schizophrenia.METHODS The present study was observational in type and based on a retrospective cohort to evaluate patterns of utilization of antipsychotic drugs using World Health Organization(WHO)core prescribing indicators and anatomical therapeutic chemical/defined daily dose indicators.We also calculated direct medical costs for a period of 6 months.RESULTS This study has found that atypical antipsychotics are the mainstay of treatment for schizophrenia in every age group and subcategories of schizophrenia.The evaluation based on WHO prescribing indicators showed a low average number of drugs per prescription and low prescribing frequency of antipsychotics from the National List of Essential Medicines 2015 and the WHO Essential Medicines List 2019.The total mean drug cost of our study was 1396 Indian rupees.The total mean cost due to the investigation in our study was 1017.34 Indian rupees.Therefore,the total mean direct medical cost incurred on patients in our study was 4337.28 Indian rupees.CONCLUSION The information from the present study can be used for reviewing and updating treatment policy at the institutional level. 展开更多
关键词 patterns of utilization Antipsychotic drugs Direct medical cost SCHIZOPHRENIA DRUGS
暂未订购
Microclimatic,physiological,and structural changes of tomato seedlings during wind-based overgrowth inhibition in vegetable nursery
19
作者 Peiji Yang Ying Liu +3 位作者 Jie Hao Zhiguo Li Fideline Tchuenbou-Magaia Jiheng Ni 《Horticultural Plant Journal》 2026年第2期369-386,共18页
Wind disturbance has emerged as a potential eco-friendly method for seedling cultivation.In this study,an electromechanical device was designed and built to investigate the effects of airflow on the micro-environment ... Wind disturbance has emerged as a potential eco-friendly method for seedling cultivation.In this study,an electromechanical device was designed and built to investigate the effects of airflow on the micro-environment and physiological activities of tomato seedlings in seedbeds by controlled experiments.The results indicated that airflow could enhance CO_(2) concentration near the seedling canopy,accelerate water evaporation from the seedling substrate,and reduce fluctuations in the temperature and humidity in microclimate.The photosynthetic rates of leaves at the 4th,7th,and 10th positions in seedlings subjected to airflow increased by 25.04%,8.23%,and 8.47%,respectively,whereas the transpiration rates increased by 15.59%,22.28%,and 13.26%,respectively when compared to the control group.Additionally,the strong seedling index of seedlings treated with airflow and exogenous iron element increased by 26.02%and 31.5%,respectively.Compared to seedlings treated with exogenous iron element,the geometric mean diameter of the pith tissue cells in the stems of seedlings subjected to airflow disturbance was reduced by approximately 18.66%,while the elastic modulus and bending strength of the stems increased by 10.01%and 5.89%,respectively.Similarly,the volume of root tissue cells decreased by 19.22%,but the elastic modulus of the roots increased by 6.46%.This study confirms that airflow significantly enhances seedling resilience to abiotic stress,yielding similar or better outcomes than exogenous iron application.It provides both theoretical and practical support for using airflow disturbance as a green technology for cultivating robust seedlings. 展开更多
关键词 Wind disturbance Tomato seedling growth MICROCLIMATE Physiological response Histological structure
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部