Results 11 to 20 of about 10,410 (133)
Jianzhu Gangjiegou Jinzhan为研究冷弯薄壁不等肢复杂卷边角钢屈曲性能和稳定承载力设计方法，对24根不同截面、长细比、宽厚比的不等肢复杂卷边角钢进行了轴压试验。试验结果表明，长细比较大且宽厚比较小的试件易发生弯扭屈曲，长细比较小而宽厚比较大的试件易发生局部屈曲或弯扭和局部相关屈曲。采用ABAQUS有限元软件对试件进行了有限元模拟，屈曲模式和承载力与试验结果吻合良好，表明建立的有限元分析模型是可行的。因此可采用经验证的有限元模型对不同长细比、卷边形式和卷边比的轴心受压不等肢复杂卷边角钢进行了参数化分析。结果表明 ...
姚行友 +3 more
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冷弯薄壁型钢拼合工字形截面柱畸变屈曲及相关屈曲轴压性能试验与直接强度法研究
Jianzhu Gangjiegou Jinzhan, 2021 为了研究冷弯薄壁型钢拼合工字形截面柱畸变屈曲及相关屈曲性能和完善直接强度法,对56根不同横截面和长细比的LG550冷弯薄壁型钢拼合工字形截面柱进行了轴压试验。试验结果表明:拼合工字形截面轴压试件表现为畸变和局部相关屈曲以及畸变、局部和整体相关屈曲两种破坏模式。对于发生畸变和局部相关屈曲试件,长细比对其承载力影响较小;但对于板件宽厚比相对较小、长细比较大发生畸变、局部和整体相关屈曲的试件,其极限承载力和刚度随长细比的增大逐渐降低。螺钉间距和端部螺钉群对其承载力影响较小。螺钉连接可满足各肢协同工作要求 ...
姚行友, 李潇
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Jianzhu Gangjiegou Jinzhan冷弯薄壁型钢（CFS）全螺栓垫板连接T形拼合柱是一种新型拼合截面柱，在全螺栓连接框架结构中承受集中荷载。目前关于全螺栓连接T形CFS拼合柱轴心受力性能的研究报道较少。基于已有的试验研究成果，建立准确可靠的T形CFS拼合柱数值分析模型，选取构件长细比、板材厚度、垫板的纵向间距等参数，研究在轴压作用下各重要参数对T形CFS拼合柱极限承载力和屈曲模态的影响。结果表明：随着长细比的增大，T形CFS拼合柱的屈曲模式由局部与畸变相关屈曲逐渐转变为整体屈曲，当长细比<104.7时 ...
陈明 +4 more
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Jianzhu Gangjiegou Jinzhan将普通C型钢截面翼缘段弯折形成折叠翼缘截面，可以降低翼缘宽厚比并增大截面高度，从而改善受弯构件的稳定性能并提高其抗弯承载力。为了研究折叠翼缘冷弯薄壁C型钢构件在纯弯状态下的抗弯性能，采用ABAQUS有限元软件建立了数值计算模型，分析了板件宽厚比、板件间角度和板件相对尺寸对构件极限承载力、屈曲破坏模式、变形特征及应力分布的影响，并与普通C型钢构件的抗弯性能进行对比分析。在此基础上，开展了抗弯承载力计算方法研究。数值分析结果表明：折叠翼缘构件发生了畸变屈曲以及局部和畸变的相关屈曲 ...
王春刚, 陈立平, 张壮南
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波长调制-直接吸收方法在线监测大气中CH 4 和CO 2 浓度
, 2020 波长调制-直接吸收光谱(WM-DAS), 同时具有直接吸收光谱(DAS)的免标定、可测量吸收率函数的优点和波长调制光谱(WMS)高信噪比、抗干扰能力强的优点. 本文利用免标定、高信噪比的WM-DAS方法结合长光程Herriott池, 在常压常温条件下, 对大气中CH4 (6046.952 cm–1)和CO2 (6330.821 cm–1)分子两条近红外吸收谱线的吸收率函数进行了测量, 其光谱拟合残差标准差可达到5.6 × 10–5.
王振, 杜艳君, 丁艳军, 彭志敏
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World Medical &Health Policy, Volume 15, Issue 4, Page 455-475, December 2023., 2023 Abstract Oppression and inequality, as critical social and structural determinants of health, are key threats to public health. Democratic stability provides institutional measures to mitigate oppression and inequality. We investigate trends in democratic backsliding in the Organization for Economic Co‐operation and Development (OECD) nations, overall,
Charley E. Willison +3 more
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Timing of hydrologic anomalies direct impacts on migration traits in a flood pulse fishery system
Journal of Applied Ecology, Volume 60, Issue 3, Page 494-506, March 2023., 2023 We designed a spectral analysis framework to quantify hydrological variation and linked it with fishery harvest records. Quantified effect sizes of hydrologic anomalous events demonstrated one designed hydrograph for fishery benefits: properly timed prolong drought followed by a strong flood pulse.
Qi Deng +4 more
wiley +1 more source
Journal of Traumatic Stress, Volume 35, Issue 4, Page 1263-1272, August 2022., 2022 Abstract Trauma exposure and posttraumatic stress symptoms (PTSS) are associated with biases in emotional face processing. Existing research has utilized a variety of methodological techniques to demonstrate hyperreactivity to threatening cues in posttraumatic stress disorder (PTSD; i.e., fearful faces), but studies to date have shown conflicting ...
Lauren A. Rutter +4 more
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Journal of Diabetes, Volume 14, Issue 4, Page 247-260, April 2022., 2022 Highlights Phosphoinositide 3‐kinase (PI3K)/Akt signaling is an emerging promising therapeutic target for diabetes. Modulation of the PI3K/Akt signaling pathway, via protein and peptide‐based biologics, parasite‐derived molecules, plant extracts, or through microRNA interactions, will regulate the processes that determine the function of β‐cells and ...
Inah Camaya +2 more
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国际教育论坛, 2020 由于高中数学有着较强的抽象性和复杂性，学生在学习中如果缺乏良好的解题方法和学习技巧，就会觉得高中数学难度较大，开始逐渐产生恐惧心理，严重者甚至直接放弃数学的学习。对此，教师必须要重视起来，在数学教学中选择相应的对策来解决这些问题，进而帮助学生提高数学成绩。对此本文笔者根据多年高中数学教学经验，就高中常见数学解题方法进行概述。
永峰 李
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