The Quantification of Micro-structural Damage of Weak Muddy Intercalation in Dry-wet Cycles Combining in-situ SEM and DIP

In order to reflect truly the damage evolution mechanism of weak muddy intercalation in dry-wet cycles, two typical weak muddy intercalations were selected for dry-wet cycles. The mineral changes of specimens were analyzed via X-ray diffraction after dry-wet cycles. By combining in-situ SEM and digital image processing(DIP), the damage evolution process and damage characteristic parameters of each stage were obtained. The experimental results indicate that the hydration and dissolution of minerals can not be a determinant factor in structure damage. The micro-structural damage is due to disintegration of mineral aggregates, leading to changes in the number and size of cracks and pores. The damage degree of specimens is related to its initial structure, and the micro-structural damage intensifies and finally tends to stabilize with cycle times increased.

In-situ SEM observation on fracture behavior of austempered silicon alloyed steel

Crack initiation, propagation and microfracture processes of austempered high silicon cast steel have been investigated by using an in-situ tensile stage installed inside a scanning electron microscope chamber. It is revealed that micro cracks always nucleate at the yielding near imperfections and the boundary of matrix-inclusions due to the stress concentration. There are four types of crack propagations in the matrix: crack propagates along the boundary of two clusters of bainitic ferrite; crack propagates along the boundary of ferrite-austenite in bainitic ferrite laths; crack propagates into bainitic ferrite laths; crack nucleates and propagates in the high carbon brittle plate shape martensite which is transformed from some blocky retained austenite due to plastic deformation. Based on the observation and analysis of microfracture processes, a schematic diagram of the crack nucleation and propagation process of high silicon cast steel is proposed.

In-situ SEM Observation of Monotonic and Cyclic Deformed Structure in Ti-2A1-2.5Zr Alloy

The SEM observation in situ of monotonic and cyclic deformed structure in Ti-ZA1-2.5Zr alloy was performed. The regularity of slippage, crack nucleation, propagation and the typical dislocation configuration were also investigated. The twin and twist play an important role in maintaining homogeneous deformation in the final plastic deformation stage.

In-situ SEM and Stereomicroscope Study Delamination Evolution of Glass Fabric Reinforced Polycarbonate Composite

The main objective of this study is to investigate the dynamic processes of the interlaminar fracture of the glass woven fabric reinforced polycarbonate composites through in-situ observation of specimen under mode Ⅰ loading by SEM and stereomicroscope. The results show that the evolution processes of interlaminar damage consist of micro-crack initiation, growth and coalescence and advance forward of the main crack tip. The mode of crack propagation in fabric composite observed here seem to be the propagation along interface, interface change and fabric separation.

基于SEM的土体微观结构三维分析与分维计算方法

土体微观结构研究很早就建立了三维空间的分形模型,但分形维数计算所需参数很难由常规土工试验得到,限制了分形理论在土体研究中的应用。基于陕西定边与甘肃兰州原状土样的扫描电镜(SEM)试验,提出了三维化处理与三角形网格原理联合方法,可以得到土体颗粒(孔隙)不同测量尺度对应的表面积与体积计算值,由此实现分形维数的计算,并通过分形理论在土水特征中的应用验证了方法的有效性与可靠性。另外,三维化处理还可获取视孔隙率、比面等土体微观结构参数,可以作为土体微观结构定量分析研究的新途径。

基于SEM的沙漠公路路基工程施工风险研究

在沙漠地区进行公路建设对完善交通网络节点、发展偏远地区经济具有重要意义。为有效探究沙漠公路路基工程施工风险,该文从人员风险、技术风险、材料风险、机械风险和环境风险5个方面出发,通过文献研究法筛选出影响沙漠公路路基工程施工风险的23项指标;基于问卷调查收集到的有效数据,构建沙漠公路路基工程施工风险的结构方程模型(Structural Equation Modeling,简称SEM);分析施工风险关键影响因素。结果表明:沙漠公路路基工程施工风险受恶劣气候、人员三违行为、风积沙质量、机械维修与保养、技术交底完整性的影响较大。提出具有针对性的控制措施,可为沙漠公路可持续发展提供参考。

基于SEM的低碳景区建设与评价——以海南省为例

采用SEM模型,构建海南景区低碳旅游建设的六个评价指标,实证结果显示海南景区低碳建设中对游客满意度影响最大的是海南优良的自然环境;海南景区低碳发展的软环境比硬环境要好,海南景区低碳管理和低碳教育这两个方面的软环境建设对游客满意度产生了显著的正向影响;而游客对海南景区在低碳交通、低碳食宿、低碳游购娱这样的硬环境建设方面的评价偏低,且这三个评价指标与游客满意度之间不存在显著影响。

基于SEM与ANN混合方法的社交问答平台用户转移行为

社交问答平台得到了用户的广泛使用,但由于各平台的功能类似,用户转移起来较为容易,这将导致用户流失。基于PPM模型,研究社交问答平台用户转移行为。采集447份有效数据,采用SEM(结构方程模型)与ANN(人工神经网络)混合方法进行分析。结果发现:推力因素(不满意度、厌倦性)和拉力因素(内容质量、用户体验)正向影响用户的转移意向,锚定因素(转移成本)负向影响转移意向,且负向调节推力因素和拉力因素的作用。ANN结果显示:不满意度是影响转移意向的最重要因素。因此,社交问答平台需要提高内容质量,改善用户体验,降低用户的不满意度和厌倦性,从而防止用户的转移行为,实现用户保持。

基于SEM的煤矿工人易发不安全行为控制研究

为了准确识别煤矿工人易发不安全行为,预防由此导致的煤矿事故,文章首先构建了由作业过程、工艺设备、环境限制和作业决策4个一级指标和操作错误等18个二级指标构成的煤矿工人不安全行为评价指标体系。其次,将结构方程模型(SEM)运用到了煤矿工人易发不安全行为控制研究中。研究结果表明:作业过程等4个一级指标(潜在变量)均对煤矿工人不安全行为的发生具有显著影响;18个二级指标(观测变量)中,有无视警示进入危险区域等14种煤矿工人易发不安全行为,且根据路径系数得到了其易发程度。最后,提出了控制煤矿工人易发不安全行为的对策。文章为煤矿工人不安全行为研究提供了一种方法。

基于Meta-SEM的建筑工人安全行为影响机制研究

为梳理建筑工人安全行为的前因变量并分析其影响机制,基于从众动机和计划行为理论,构建了建筑工人安全行为影响机制理论模型,运用元分析-结构方程模型(Meta-Structural Equation Modeling,Meta-SEM)法对国内外64项实证研究中的128个独立样本进行系统分析,以明确各前因变量与建筑工人安全行为的相互作用关系并探讨企业规模的调节作用。结果表明:在个体层面,安全意识、安全态度、安全动机与建筑工人安全行为的相关系数分别为0.663、0.513、0.509;在组织管理层面,安全氛围与建筑工人安全行为的相关系数为0.678;安全意识、安全态度、安全动机是安全氛围与建筑工人安全行为之间的中介变量;企业规模对安全意识、安全动机、安全氛围与建筑工人安全行为的关系间存在显著调节作用,其中,中小型企业的影响更显著。研究结论可为后续建筑工人安全行为研究提供一定的理论基础,也为建筑业管理者提供了管理依据。

基于SEML & ML模型的旅客出行行为选择研究

文章关注不同运距下旅客对航空、高铁、空铁联运等出行方式的选择行为。研究以成都为中心的三个OD对,采用RP和SP调查相结合的方法进行客流调查。在此基础上,构建了SEM-Logit模型(SEML)和随机参数Logit模型(ML),考虑个人社会经济属性、心理潜变量和出行方式特征。结果表明,SEML模型能更好地描绘旅客出行的心理特征因素,而ML模型更准确地描述旅客的个人特征和出行特征,显示各自优势。针对1 000公里左右运距、中转时间和出行费用对航空市场分担率影响较小,对高铁影响较大;对空铁联运航空出行方式的市场分担率影响也较小,需要加强相关产品推广。文章为了解旅客选择行为和出行方式市场分担率提供了有益信息,并为改进交通产品和服务提供了指导。

基于拓展计划行为理论的电子竞技用户行为SEM模型构建及分析

为进一步厘清电竞用户行为的形成过程,给电竞产业持续健康发展提供一定的决策参考,基于拓展计划行为理论和使用与满足理论对我国电竞用户行为进行SEM模型的构建及分析。结论表明:替代成就、审美享受、戏剧体验、社会互动四类需求动机因素均能正向影响电竞用户的行为态度。其中,社会互动的影响最为显著;电竞用户的行为态度、主观规范和知觉行为控制既能通过电竞参与意向的中介效应正向影响电竞参与行为,也能直接产生正向影响,且主观规范对电竞参与意向的影响最为显著,知觉行为控制对电竞参与行为的直接影响最为显著;电竞参与意向在以上三个自变量与电竞参与行为之间均起到了不完全中介作用。

Assessing the conservation impact of Chinese indigenous chicken populations between ex-situ and in-situ using genome-wide SNPs

Conservation programs require rigorous evaluation to ensure the preservation of genetic diversity and viability of conservation populations. In this study, we conducted a comparative analysis of two indigenous Chinese chicken breeds, Gushi and Xichuan black-bone, using whole-genome SNPs to understand their genetic diversity, track changes over time and population structure. The breeds were divided into five conservation populations(GS1, 2010, ex-situ;GS2, 2019, ex-situ;GS3, 2019, in-situ;XB1, 2010, in-situ;and XB2, 2019, in-situ) based on conservation methods and generations. The genetic diversity indices of three conservation populations of Gushi chicken showed consistent trends, with the GS3 population under in-situ strategy having the highest diversity and GS2 under ex-situ strategy having the lowest. The degree of inbreeding of GS2 was higher than that of GS1 and GS3. Conserved populations of Xichuan black-bone chicken showed no obvious changes in genetic diversity between XB1 and XB2. In terms of population structure, the GS3 population were stratified relative to GS1 and GS2. According to the conservation priority, GS3 had the highest contribution to the total gene and allelic diversity in GS breed, whereas the contribution of XB1 and XB2 were similar. We also observed that the genetic diversity of GS2 was lower than GS3, which were from the same generation but under different conservation programs(in-situ and ex-situ). While XB1 and XB2 had similar levels of genetic diversity. Overall, our findings suggested that the conservation programs performed in ex-situ could slow down the occurrence of inbreeding events, but could not entirely prevent the loss of genetic diversity when the conserved population size was small, while in-situ conservation populations with large population size could maintain a relative high level of genetic diversity.

In-situ AFM and quasi-in-situ studies for localized corrosion in Mg-9Al-1Fe-(Gd) alloys under 3.5 wt.% NaCl environment

Revealing the localized corrosion process of Mg alloy is considered as one of the most significant ways for improving its corrosion resistance.The reliable monitor should be high distinguishability and real-time in liquid environment.Herein,Mg-9Al-1Fe and Mg-9Al-1Fe-1Gd alloys were designed to highlight the impact of intermetallic on the corrosion behaviour.In-situ AFM with a special electrolyte circulation system and quasi-in-situ SEM observation were used to monitor the corrosion process of the designed alloys.SEM-EDS and TEM-SAED were applied to identify the intermetallic in the designed alloys,and their volta potentials were measured by SKPFM.According to the real-time and real-space in-situ AFM monitor,the corrosion process consisted of dissolution of anodicα-Mg phase,accumulation of corrosion products around cathodic phase and shedding of some fine cathodic phase.Then,the localized corrosion process of Mg alloy was revealed combined with the results of the monitor of corrosion process and Volta potential difference.

科创板上市公司的信用风险体系构建、评价与组态分析——基于DBN-SEM-fsQCA方法

注册制逐步推广与高技术型产业特性使得科创板上市公司的信用风险评价日趋复杂。研究通过DBN-SEM-fsQCA的方法组合,实现对科创板上市公司信用风险体系的构建、评价与组态分析。研究结果表明:基于DBN选取的关键财务指标能够准确反映科创板上市公司的信用风险情况;在SEM视角下,盈利能力与信用风险联系密切,偿债能力、成长能力、营运能力与信用风险显著相关;基于组态视角,科创板上市公司的信用风险模式主要分为成长导向型、成长缺失与营运主导型、盈利与成长互补型、盈利导向型四种类型。为此,科创板上市公司可以通过扩大产业规模来获取市场份额优势,或者增加技术研发投入来取得超额利润,以及联合城市区位条件来实现信用风险的多层次把控。

基于SEM的装配式建筑施工安全风险评价

为了加强装配式建筑在施工过程的安全管理,有效降低施工阶段存在的安全风险,针对人员、机械、技术、管理和环境5个方面,筛选出24个安全风险因素,运用灰色关联分析和专家打分方法建立安全风险评价指标体系,结合问卷调查数据,借助SPSS和AMOS软件建立结构方程模型(SEM)对装配式建筑施工安全风险指标进行验证性分析,并利用SEM的路径系数对各指标进行权重计算.研究结果表明:人员、机械、技术、管理、环境在装配式建筑施工阶段均具有不可忽略的影响,其中影响最大的是机械因素,其次是人员因素;及时监督管理预制构件的生产质量和构件的出厂质量以及大力培训施工人员安全意识是有效降低装配式建筑施工安全风险的关键.

Anomalous bond lengthening in compressed magnetic doped semiconductor Ba(Zn_(0.95)Mn_(0.05))_(2)As_(2)

Applying pressure has been evidenced as an effective method to control the properties of semiconductors,owing to its capability to modify the band configuration around Fermi energy.Correspondingly,structural evolutions under external pres-sures are required to analyze the mechanisms.Herein high-pressure structure of a magnetic doped semiconductor Ba(Zn_(0.95)Mn_(0.05))_(2)As_(2)is studied with combination of in-situ synchrotron X-ray diffractions and diamond anvil cells.The materials become ferromagnetic with Curie temperature of 105 K after further 20%K doping.The title material undergoes an isostruc-tural phase transition at around 19 GPa.Below the transition pressure,it is remarkable to find lengthening of Zn/Mn-As bond within Zn/MnAs layers,since chemical bonds are generally shortened with applying pressures.Accompanied with the bond stretch,interlayer As-As distances become shorter and the As-As dimers form after the phase transition.With further compres-sion,Zn/Mn-As bond becomes shortened due to the recovery of isotropic compression on the Zn/MnAs layers.

An in-situ self-etching enabled high-power electrode for aqueous zinc-ion batteries

Sluggish storage kinetics is considered as the main bottleneck of cathode materials for fast-charging aqueous zinc-ion batteries(AZIBs).In this report,we propose a novel in-situ self-etching strategy to unlock the Palm tree-like vanadium oxide/carbon nanofiber membrane(P-VO/C)as a robust freestanding electrode.Comprehensive investigations including the finite element simulation,in-situ X-ray diffraction,and in-situ electrochemical impedance spectroscopy disclosed it an electrochemically induced phase transformation mechanism from VO to layered Zn_(x)V_(2)O_5·nH_(2)O,as well as superior storage kinetics with ultrahigh pseudocapacitive contribution.As demonstrated,such electrode can remain a specific capacity of 285 mA h g^(-1)after 100 cycles at 1 A g^(-1),144.4 mA h g^(-1)after 1500 cycles at 30 A g^(-1),and even 97 mA h g^(-1)after 3000 cycles at 60 A g^(-1),respectively.Unexpectedly,an impressive power density of 78.9 kW kg^(-1)at the super-high current density of 100 A g^(-1)also can be achieved.Such design concept of in-situ self-etching free-standing electrode can provide a brand-new insight into extending the pseudocapacitive storage limit,so as to promote the development of high-power energy storage devices including but not limited to AZIBs.

Microstructural characterization and mechanical properties of(TiC+TiB)/TA15 composites prepared by an in-situ synthesis method

Titanium matrix composites reinforced with ceramic particles are considered a promising engineering material due to their combination of high specific strength,low density,and high modulus.In this study,the TA15-based composites reinforced with a volume fraction of 10% to 25%(TiB+TiC)were prepared using powder metallurgy and casting technique.Microstructural characterization and phase constitution were examined using optical microscopy(OM),scanning electron microscopy(SEM),and X-ray diffraction(XRD).In addition,the microhardness,room temperature(RT)and high temperature(HT)tensile properties of the composites were evaluated.Results revealed that the reinforcements are distributed uniformly even in the composites with a high volume of TiB and TiC.However,as the volume fraction exceeds 15%,TiB and TiC particles become coarsening and exhibit rod-like and dendritic-like morphology.Microhardness increases gradually from 321.2 HV for the base alloy to a maximum of 473.3 HV as the reinforcement increases to 25vol.%.Tensile test results indicate that a reinforcement volume fraction above 20% is beneficial for enhancing tensile strength and yield strength at high temperatures,but it has an adverse effect on room temperature elongation.Conversely,if the reinforcement volume fraction is below 20%,it can improve high-temperature elongation when the temperature exceeds 600℃.

In-situ interfacial passivation and self-adaptability synergistically stabilizing all-solid-state lithium metal batteries

The function of solid electrolytes and the composition of solid electrolyte interphase(SEI)are highly significant for inhibiting the growth of Li dendrites.Herein,we report an in-situ interfacial passivation combined with self-adaptability strategy to reinforce Li_(0.33)La_(0.557)TiO_(3)(LLTO)-based solid-state batteries.Specifically,a functional SEI enriched with LiF/Li_(3)PO_(4) is formed by in-situ electrochemical conversion,which is greatly beneficial to improving interface compatibility and enhancing ion transport.While the polarized dielectric BaTiO_(3)-polyamic acid(BTO-PAA,BP)film greatly improves the Li-ion transport kinetics and homogenizes the Li deposition.As expected,the resulting electrolyte offers considerable ionic conductivity at room temperature(4.3 x 10~(-4)S cm^(-1))and appreciable electrochemical decomposition voltage(5.23 V)after electrochemical passivation.For Li-LiFePO_(4) batteries,it shows a high specific capacity of 153 mA h g^(-1)at 0.2C after 100 cycles and a long-term durability of 115 mA h g^(-1)at 1.0 C after 800 cycles.Additionally,a stable Li plating/stripping can be achieved for more than 900 h at 0.5 mA cm^(-2).The stabilization mechanisms are elucidated by ex-situ XRD,ex-situ XPS,and ex-situ FTIR techniques,and the corresponding results reveal that the interfacial passivation combined with polarization effect is an effective strategy for improving the electrochemical performance.The present study provides a deeper insight into the dynamic adjustment of electrode-electrolyte interfacial for solid-state lithium batteries.