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A Comprehensive Study on the Consequences of Gap-Graded Sands Considering the Loss of Fine Particles

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Journal of Earth Science 2024年第2期35卷 597-612页

作者： Weiping Liu yu Gan yunwei Cui Faming Huang Lina Hu School of Civil Engineering and Architecture Nanchang UniversityNanchang330031China

Water and sand leakage disasters are likely to occur during construction in water-rich sand layer areas,resulting in ground *** stress-strain action characteristics of discontinuous graded sand under different internal erosion degrees,and the evolution mechanism of water and sand leakage disasters caused by the internal erosion need to be further ***,this paper takes the discontinuous graded sand in a water rich sand layer area in Nanchang City of China as the research *** the influence of different fine particle losses(0,10%,20%and 30%)under the internal erosion of sand,the salt solution method is used to realize the specified loss of fine particles in the internal *** stress-strain behavior after the loss of fine particles due to internal erosion is studied by triaxial shear ***,the physical model test and PFC-CFD method are both used to study the evolution rules of water and sand leakage disaster considered the influence of internal erosion *** show that:(1)under the same confining pressure,the peak failure strength of sand samples decreases along with the increase of fine particle loss.(2)In the water and sand leakage test of saturated sand,a natural filter channel is formed above the observed soil *** greater the loss of fine particles,the steeper and wider the collapse settlement area.(3)The relationship between the cumulative amount of water and sand leakage and time is *** total mass loss of sand increases along with the increase of internal erosion degree.(4)After the soil arch is formed around the damaged opening,the sand continues to converge above the soil arch under the action of water flow,resulting in the dense convergence of contact force chains.

关键词： sandy soil internal erosion stress and strain water and sand leakage PFC3D engineering geology

A Simple Urea Approach to N-Dopedα-Mo_(2)C with Enhanced Superconductivity

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Chinese Physics Letters 2024年第10期41卷 103-111页

作者： Longfu Li Lei Shi Lingyong Zeng Kuan Li Peifeng yu Kangwang Wang Chao Zhang Rui Chen Zaichen Xiang yunwei Zhang Huixia Luo School of Materials Science and Engineering State Key Laboratory of Optoelectronic Materials and TechnologiesGuangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesKey Lab of Polymer Composite&Functional MaterialsSun Yat-Sen UniversityGuangzhou 510275China School of Physics Guangdong Provincial Key Laboratory of Magnetoelectric Physics and DevicesSun Yat-Sen UniversityGuangzhou 510275China

Chemical doping is a critical factor in the development of new superconductors or optimizing the superconducting transition temperature(T_(c))of the parent superconducting ***,a new simple urea approach is developed to synthesize the N-dopedα-Mo_(2)*** from the simple urea method,a broad superconducting dome is found in the Mo_(2)C1−xNx(0≤x≤0.49)compositions.X-ray diffraction results show that the structure of𝛼α-Mo_(2)C remains unchanged and there is a variation of lattice parameters with nitrogen ***,magnetic susceptibility,and heat capacity measurement results confirm that T_(c)was strongly increased from 2.68K(x=0)to 7.05K(x=0.49).First-principles calculations and our analysis indicate that increasing nitrogen doping leads to a rise in the density of states at the Fermi level and doping-induced phonon softening,which enhances electron–phonon *** results in an increase in𝑇T_(c)and a sharp rise in the upper critical *** findings provide a promising strategy for fabricating transition metal carbonitrides and provide a material platform for further study of the superconductivity of transition metal carbides.

关键词： softening doping critical

Transcription factor OsWRKY11 induces rice heading at low concentrations but inhibits rice heading at high concentrations

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Journal of Integrative Plant Biology 2024年第7期66卷 1385-1407页

作者： Lirong Zhao yunwei Liu Yi Zhu Shidie Chen Yang Du Luyao Deng Lei Liu Xia Li Wanqin Chen Zhiyu Xu Yangyang Xiong You Ming Siyu Fang Ligang Chen Houping Wang Diqiu yu CAS Key Laboratory of Tropical Plant Resources and Sustainable Use Xishuangbanna Tropical Botanical GardenThe Chinese Academy of SciencesMengla 666303China College of Life Sciences University of Chinese Academy of SciencesBeijing 101408China State Key Laboratory for Conservation and Utilization of Bio‐resources in yunnan Yunnan UniversityKunming 650500China School of Life Sciences Yunnan UniversityKunming 650500China Southwest United Graduate School Yunnan UniversityKunming 650092China

The heading date of rice is a crucial agronomic characteristic that influences its adaptability to different regions and its productivity *** the involvement of WRKY transcription factors in various biological processes related to development,the precise mechanisms through which these transcription factors regulate the heading date in rice have not been well *** present study identified OsWRKY11 as a WRKY transcription factor which exhibits a pivotal function in the regulation of the heading date in rice through a comprehensive screening of a clustered regularly interspaced palindromic repeats(CRISPR)-CRISPR-associated nuclease 9 mutant library that specifically targets the WRKY genes in *** heading date of oswrky11 mutant plants and OsWRKY11-overexpressing plants was delayed compared with that of the wild-type plants under short-day and long-day *** investigation revealed that OsWRKY11 exerts dual effects on transcriptional promotion and suppression through direct and indirect DNA binding,*** normal conditions,OsWRKY11 facilitates flowering by directly inducing the expression of OsMADS14 and *** presence of elevated levels of OsWRKY11 protein promote formation of a ternary protein complex involving OsWRKY11,Heading date 1(Hd1),and Days to heading date 8(DTH8),and this complex then suppresses the expression of Ehd1,which leads to a delay in the heading *** investigation revealed that a mild drought condition resulted in a modest increase in OsWRKY11 expression,promoting ***,under severe drought conditions,a significant upregulation of OsWRKY11 led to the suppression of Ehd1 expression,ultimately causing a delay in heading *** findings uncover a previously unacknowledged mechanism through which the transcription factor OsWRKY11 exerts a dual impact on the heading date by directly and indirectly binding to the promoters of target genes.

关键词： heading date OsWRKY11 rice transcription factors

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单根碳纳米管场致发射表面电荷分布研究

固体电子学研究与进展 2005年第4期25卷 432-436页

作者：刘金平俞云伟徐新平黄新堂华中师范大学纳米科技研究院武汉430079

考虑碳纳米管尺寸及端帽形状,计算得到了比较精确的金属型纳米管表面电荷密度相对分布曲线。与先前的理论结果作比较,消除了曲线上的波动,曲线相对抬高,尖端附近电荷量所占比例减小。进一步研究了长度、半径和长径比对电荷密度相对分布... 详细信息

考虑碳纳米管尺寸及端帽形状,计算得到了比较精确的金属型纳米管表面电荷密度相对分布曲线。与先前的理论结果作比较,消除了曲线上的波动,曲线相对抬高,尖端附近电荷量所占比例减小。进一步研究了长度、半径和长径比对电荷密度相对分布曲线的影响,表明长度主要影响管身电荷密度相对分布,半径主要影响尖端电荷密度相对分布。在忽略其他条件影响下,长径比相同的碳纳米管,电荷密度相对分布曲线趋势完全相同。

关键词：碳纳米管场致发射表面电荷分布长径比

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快速射电暴高能辐射的相关研究

中国科学：物理学、力学、天文学 2020年第12期50卷 21-32页

作者：王敏浩高鹤王界双李兵俞云伟刘彤戴子高北京师范大学天文系北京100875 上海交通大学李政道研究所上海200240 中国科学院高能物理研究所北京100049 华中师范大学物理科学与技术学院武汉430079 厦门大学天文系厦门361005 南京大学天文与空间科学学院南京210023

快速射电暴(FRB)是一类高度色散且短时标的射电爆发现象,大多数定位于高银纬地区并且光变曲线呈简单的单脉冲结构.FRB在其大致毫秒量级的持续时间内可释放出的总能量约为1038–1040erg,其发生率约为103–104Gpc-3yr-1,远高于同样条件下... 详细信息

快速射电暴(FRB)是一类高度色散且短时标的射电爆发现象,大多数定位于高银纬地区并且光变曲线呈简单的单脉冲结构.FRB在其大致毫秒量级的持续时间内可释放出的总能量约为1038–1040erg,其发生率约为103–104Gpc-3yr-1,远高于同样条件下伽马暴(GRB)的事件率.目前已公布超过100个FRB事件,人们构建了几十个理论模型来试图解释这类现象,如双致密星并合、致密天体的坍缩、中子星与小天体的碰撞及相互作用、磁星的巨耀发以及脉冲星的巨脉冲等.但依赖单一射电波段的观测还很难对诸多模型进行辨别,而FRB的多波段辐射很有可能对其模型及爆发机制给予有效的甄别或限制,因而多波段探测对FRB的研究至关重要.本文详细地归纳和整理了FRB的主要理论模型,并重点分析了各种理论预言的高能电磁辐射的情况,同时介绍了我国正在研制建设中的GECAM卫星将如何凭借其在伽马射线的全天、高灵敏度及宽能段的监测能力,对这些理论模型进行一定的筛选与验证.

关键词：中子星脉冲星射电与微波

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面向失配的图像隐写分析研究进展

北京交通大学学报 2024年第2期48卷 102-114页

作者：李芸伟张祝薇于丽芳曹鹏曹刚北京印刷学院信息工程学院北京102600 中国传媒大学计算机与网络空间安全学院北京100024

尽管隐写分析在实验室环境下取得了显著的进步,但是在实际应用中,由于训练集和测试集的载体来源、隐写算法和嵌入率经常不同,导致隐写分析器性能下降,这种现象称为失配,严重阻碍了隐写分析的实际应用.因此,对目前面向失配问题的主要隐... 详细信息

尽管隐写分析在实验室环境下取得了显著的进步,但是在实际应用中,由于训练集和测试集的载体来源、隐写算法和嵌入率经常不同,导致隐写分析器性能下降,这种现象称为失配,严重阻碍了隐写分析的实际应用.因此,对目前面向失配问题的主要隐写分析方法进行了分析与总结.根据解决失配问题的思路,将现有失配隐写分析方法分为3类,即设计训练集、取证辅助和无监督领域适应,并对各类方法进行梳理和对比.基于对比结果,探讨了当前基于无监督领域适应的深度隐写分析模型面临的挑战以及未来的发展方向.研究结果表明:基于无监督领域适应的深度隐写分析模型是目前解决失配问题的最有效方案,领域对齐、中间域桥接、对抗学习等是设计该类深度隐写分析模型的主流思想;引入类别等细粒度信息以提高基于无监督领域适应的深度隐写分析模型的性能是未来研究的方向;针对不平衡样本及单/小样本等更恶劣的失配问题的解决方案仍待进一步探索.

关键词：隐写分析深度学习失配无监督领域适应

基于MLP-Bagging集成分类模型的在线学习行为分析

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云南大学学报（自然科学版） 2024年第5期46卷 852-861页

作者：普运伟姜萤田春瑾余永鹏昆明理工大学信息工程与自动化学院云南昆明650500 昆明理工大学计算中心云南昆明650500

针对教育者难以对学习者多样化的在线学习行为进行监测和研判等问题,提出一种带嵌入层的MLP-Bagging集成分类模型对学习者的在线学习行为进行分析与判别.考虑到学习者的在线学习行为以及个体特性,从学习准备行为、知识获取行为、交互学... 详细信息

针对教育者难以对学习者多样化的在线学习行为进行监测和研判等问题,提出一种带嵌入层的MLP-Bagging集成分类模型对学习者的在线学习行为进行分析与判别.考虑到学习者的在线学习行为以及个体特性,从学习准备行为、知识获取行为、交互学习行为、学习巩固行为和辅助特征5个方面构建在线学习行为模型,并采用MLP-Bagging集成分类模型对学习者进行分类判别.实验结果表明,所构建的学习模型可对在线学习者的学习行为进行符合实际的建模,加入辅助特征有利于对各类学习者的在线学习行为进行深入的分析与指导,并且在分类模型中加入嵌入层可以有效克服标签编码带来的数据冗余和误差缺陷,从而获得更好的分类效果.与其他分类模型相比,融合多个MLP分类器的Bagging集成模型可以减少单个MLP分类器的方差,其分类准确率达到98.72%,具有较好的实际应用价值.

关键词：在线学习行为学习者分类嵌入层 MLP神经网络 Bagging集成学习

阿尔茨海默病“肾虚酿毒伤髓”病机演变模型构建及其应用

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辽宁中医杂志 2024年第7期51卷 193-196,I0004页

作者：钱小溪陆韵薇吴同越于顾然南京中医药大学附属医院江苏南京210029

目的根据肾-骨髓-血细胞-脑髓相互影响的中西医理论,建立一种阿尔茨海默病(Alzheimer′s disease,AD)“肾虚酿毒伤髓”模型,筛查AD有效中药,并初步探讨该模型的临床应用。方法由于AD患者B淋巴细胞可以促进神经细胞产生Aβ毒素。将肾虚... 详细信息

目的根据肾-骨髓-血细胞-脑髓相互影响的中西医理论,建立一种阿尔茨海默病(Alzheimer′s disease,AD)“肾虚酿毒伤髓”模型,筛查AD有效中药,并初步探讨该模型的临床应用。方法由于AD患者B淋巴细胞可以促进神经细胞产生Aβ毒素。将肾虚型AD患者外周血提取B淋巴细胞永生化,建立淋巴母细胞系(lymphoblastoid cell lines,LCL),并与人神经上皮瘤细胞(SKNMC)共培养,产生Aβ毒素,制成阿尔茨海默病“肾虚酿毒伤髓”模型。通过免疫荧光法检测Aβ_(1-42)的表达量,筛查有抑制Aβ_(1-42)生成的中药。并初步探讨该模型的临床应用。结果与正常对照组相比,肾虚型AD模型中神经细胞Aβ_(1-42)的生成明显增多,具有统计学意义(P<0.01)。与肾虚模型组相比,白术、人参、黄芪、生地黄、梓醇减少了神经细胞Aβ_(1-42)的生成,差异具有统计学意义(P<0.01)。结论白术、人参、黄芪、生地黄、梓醇可以减少AD中Aβ_(1-42)的生成。该模型除了筛查有效中药外,可以作为AD患者“肾虚酿毒”严重程度的生物标记物,及评价中药干预的疗效指标。

关键词：阿尔茨海默病肾虚酿毒伤髓 B淋巴细胞体外模型

Damage and fracture model for eutectic composite ceramics

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Acta Mechanica Sinica 2019年第1期35卷 190-200,I0006页

作者： Jinfeng yu Xinhua Ni Xiequan Liu yunwei Fu Zhihong Du Department of Vehicle and Electric Engineering Army Engineering UniversityShijiazhuang 050003China Army Infantry College Nanchang 330000China Xichang Satellite Launch Center Xichang 615000China

Study of damage and fracture models to analyze the fracture mechanism of eutectic composite ceramics is of considerable importance because no accurate fracture models are available for these materials. Eutectic composite ceramics are composed of microcells with random direction. We present herein a model that predicts the damage and fracture of eutectic composite ceramics based on analysis of defect stability and the damage localization band. Firstly, given the microstructure of eutectic composite ceramics, a mesodomain and a microcell model are constructed. The local stress field in the mesodomain is then analyzed based on the interaction direct derivative estimate. Secondly, the stability of a defect around particles in a microcell is analyzed, and the stress intensity factor of an annular defect under the applied stress field and the residual stress field in the particle are calculated. The stress intensity factor of a defect is controlled by the residual stress when the defect extension is small. However, it is controlled by the applied stress when the defect extension is large. Finally, a model for the damage localization band at the crack tip is constructed based on the Dugdale-Barenblatt model. The residual intensity is the important factor affecting the length of the damage localization band. When the damage variables reach their largest value, the residual in ten sity and the length of the damage localization band attain their minimum value. This work provides the theoretical basis for further study of the damage mechanics of eutectic composite ceramics and guides the engineering applications of these materials.

关键词： Microcell Interaction direct derivative estimate Defect stability Damage localization band