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Numerical simulation of melt flow and temperature field during DC casting 2024 aluminium alloy under different casting conditions

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China Foundry 2024年第4期21卷 387-396页

作者： Jin-chuan Wang Yu-bo Zuo Qing-feng zhu Jing Li Rui Wang Xu-dong Liu Key Laboratory of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Engineering Research Center of Advanced Materials Preparing Technology Ministry of EducationShenyang 110819China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

Casting speed,casting temperature and secondary cooling water flow rate are the main process parameters affecting the DC casting *** parameters significantly influence the flow and temperature fields during casting,which are crucial for the quality of the ingot and can determine the success or failure of the casting *** simulation,with the advantages of low cost,rapid execution,and visualized results,is an important method to study and optimize the DC casting *** the present work,a simulation model of DC casting 2024 aluminum alloy was established,and the reliability of the model was ***,the influence of casting parameters on flow field and temperature field was studied in detail by numerical simulation *** show that with the increase of casting speed,the melt flow becomes faster,the depths of slurry zone and mushy zone increase,and the variation of slurry zone depth is greater than that of mushy *** an increase in casting temperature,the melt flow rate increases,the depth of the slurry zone becomes shallower,and the depth of the mushy zone experiences only minor *** simulation results further indicate that the increase of the flow rate of the secondary cooling water slightly reduces the depths of both slurry and mushy zone.

关键词： aluminium DC casting flow field temperature field numerical simulation

Mechanics model and numerical analysis of floor heave in soft rock roadway

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Journal of Coal Science & Engineering(China) 2011年第4期17卷 372-376页

作者： zhu chuan-qu WANG Yong CHEN Miao-ming CHEN Zhi WANG Hong-ming Hunan Key Laboratory of Safe Mining Techniques of Coal Mines Hunan University of Science and Technology Xiangtan411201 China

The mechanism of floor heave was analyzed by establishing mechanics models and solving differential equations. The amount of floor heave is proportional to the abutment pressure of surrounding rock, roadway width, and the distance of support pressure peak to the roadway and is inversely proportional to the elastic modulus of floor rock. Using FLAC2D to simulate floor rock grouting in soft rock roadway verifies the active role of floor rock grouting in the floor controlling of soft rock roadway; floor rock grouting and grouting range directly impact on the stability scope of surrounding rock, namely, with the increase of grouting range, the subsidence of roof, the approach of both sides, and the amount of floor heave decreased gradually, the stability of surrounding rock is enhanced

关键词： soft rock roadway floor heave floor rock grouting numerical simulation

Microstructure Recrystallization and Mechanical Properties of a Cold-Rolled TiNbZrTaHf Refractory High-Entropy Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 633-647页

作者： chuan Rong Jieren Yang Xiaoliang Zhao Ke Huang Ying Liu Xiaohong Wang Dongdong zhu Ruirun Chen College of Materials Science and Engineering Sichuan UniversityChengdu610065China Key Laboratory of Air-Driven Equipment Technology of Zhejiang Province Quzhou UniversityQuzhou324000China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin150001China

The equiatomic TiNbZrTaHf alloy was successfully rolled at room temperature with the reduction of ~ 85%. The microstructure and tensile properties were investigated after cold working and annealing. It was determined that the recrystallization temperature of the TiNbZrTaHf alloy between 850 and 900 ℃. Complete recrystallization and normal grain growth occurred, the high stability of single phase was maintained after annealing at 1000, 1200, and 1400 ℃. But the precipitated phase appeared after long term annealing, as seen after 500 h at 1000 ℃. After cold working, the tensile strength and the elongation of TiNbZrTaHf were 1137 MPa and 25.1%, respectively. The annealed alloy has a high tensile strength (σ_(b )= 863 MPa) and ductility (ε_(e )= 28.5%). Moreover, the oxidation of TiNbZrTaHf alloy at elevated temperatures has a significant impact on its mechanical properties. The poor oxidation resistance of TiNbZrTaHf can accelerate tensile failure by inducing fractures at grain boundaries.

关键词： Refractory high entropy alloy Cold rolling Recrystallization Oxidation resistance Mechanical properties

盐酸氟西汀胶囊和草酸艾司西酞普兰片治疗首发抑郁症的临床效果研究

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中国现代医生 2024年第21期62卷 108-110,121页

作者：马增明陈进东夏玉平魏晓倩朱传安黄志源厦门市仙岳医院厦门医学院附属仙岳医院福建省精神医学中心福建省精神疾病临床医学研究中心住院部福建厦门361012 厦门市仙岳医院厦门医学院附属仙岳医院福建省精神医学中心福建省精神疾病临床医学研究中心院办公室福建厦门361012

目的探讨盐酸氟西汀胶囊和草酸艾司西酞普兰片治疗首发抑郁症的临床疗效。方法选取2023年2月至11月在厦门市仙岳医院中西医结合14病区住院的80例首发抑郁症患者,根据随机数字表法将患者分为盐酸氟西汀胶囊组(n=40)和草酸艾司西酞普兰片... 详细信息

目的探讨盐酸氟西汀胶囊和草酸艾司西酞普兰片治疗首发抑郁症的临床疗效。方法选取2023年2月至11月在厦门市仙岳医院中西医结合14病区住院的80例首发抑郁症患者,根据随机数字表法将患者分为盐酸氟西汀胶囊组(n=40)和草酸艾司西酞普兰片组(n=40);治疗前与治疗4周后对患者进行汉密顿抑郁量表(Hamilton depression scale,HAMD)评估,分析药物的临床治疗效果。结果药物治疗4周后,两组患者的HAMD评分均较本组治疗前显著降低(P0.05)。两组患者的总有效率比较,差异无统计学意义(P>0.05)。结论草酸艾司西酞普兰片与盐酸氟西汀胶囊治疗首发抑郁症患者均有效,两组患者的总有效率相近。

关键词：首发抑郁症草酸艾司西酞普兰片盐酸氟西汀胶囊临床疗效

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Analysis of stability of coal pillars with multi-coal seam strip mining

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中国有色金属学会会刊：英文版 2011年第S3期21卷 549-555页

作者： ZHANG Li-ya, DENG Ka-zhong, zhu chuan-guang, XING Zheng-quan Jiangsu Key Laboratory of Resources and Environmental Information Engineering, China University of Mining and Technology, Xuzhou 221116, China Jiangsu Key Laboratory of Resources and Environmental Information Engineering China University of Mining and Technology Xuzhou 221116 China

Strip mining is one of the efficient measures to control surface subsidence and mining damage. However, the researches on the laws of the geological mining factors to upper and lower pillar's stability are still deficient in multi-coal seam strip mining at present. Based on the three dimension fast Lagrangian analysis of continua (short for FLAC3D) numerical simulation software, the laws of the stress increasing coefficient on the coal pillar and its stability were systematically studied for different depths, different mining widths, different interlayer spacings, different mining thicknesses, different properties of interstratified rock and the spacial relations of the upper and lower pillars in vertical alignment in multi-coal seam strip mining. The function relation between the stress increasing coefficient of upper and lower pillars with the mining depth, mining widths, interlayer spacing, mining thickness, property of interstratified rock and the spatial relationship were obtained.

关键词： multi-coal seam strip mining FLAC3D numerical simulation stability of coal pillar

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库仑土压系数简易计算法

岩土力学 2007年第9期28卷 1789-1795页

作者：朱传培浙江建设职业技术学院杭州311231

根据库仑主动土压力系数与填土内摩擦角、坡角、墙背倾角等参数的内在关系,对库仑主动土压力系数随不同参数的变化规律进行了分析,并在原数解法的基础上推导出一种新的简易计算公式。通过数解法与简易法的对比分析表明,当保证率为95%时... 详细信息

根据库仑主动土压力系数与填土内摩擦角、坡角、墙背倾角等参数的内在关系,对库仑主动土压力系数随不同参数的变化规律进行了分析,并在原数解法的基础上推导出一种新的简易计算公式。通过数解法与简易法的对比分析表明,当保证率为95%时,简易法相对于库仑计算值的最大误差小于14%。

关键词：库仑土压力系数简易计算方法填土内摩擦角墙背倾角坡角

The relationship between physical activity in early pregnancy and hypertensive disorders of pregnancy: a cohort study in Chinese women

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World Journal of Emergency Medicine 2023年第3期14卷 204-208页

作者： Qian Lu Shi-jiao Yan Huan-jun Chen Xiong-fei Pan Yi-xiang Ye Xing-yue Song Ri-xing Wang chuan-zhu Lyu International School of Public Health and One Health Hainan Medical UniversityHaikou 570100China Research Unit of Island Emergency Medicine Chinese Academy of Medical SciencesHainan Medical UniversityHaikou 570100China Section of Epidemiology and Population Health Ministry of Education Key Laboratory of Birth Defects and Related Diseases of Women and ChildrenWest China Second University Hospital&West China Biomedical Big Data CenterWest China HospitalSichuan UniversityShuangliu Institute of Women's and Children's HealthShuangliu Maternal and Child Health HospitalChengdu 610041China Department of Epidemiology and Biostatistics School of Public HealthTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430000China Department of Emergency Hainan Clinical Research Center for Acute and Critical Diseasesthe Second Affi liated Hospital of Hainan Medical UniversityHaikou 570100China Emergency Medicine Center Sichuan Provincial People's HospitalUniversity of Electronic Science and Technology of ChinaChengdu 610072China Ministry of Education Key Laboratory of Emergency and Trauma Hainan Medical UniversityHaikou 570100China

BACKGROUND:We aimed to examine prospective associations between diff erent intensities and diff erent types of physical activity(PA)in early pregnancy and hypertensive disorders of pregnancy(HDP)among Chinese ***:A total of 6,820 pregnant women from the Tongji-Shuangliu Birth Cohort were included in this *** pregnancy physical activity questionnaire(PPAQ)was used to assess PA,including household/caregiving,occupational,sports/exercise,and transportation activities in the first trimester of *** diagnosis of HDP was collected,including gestational hypertension(GH)and preeclampsia(PE).Data were analyzed by unconditional multivariate logistic regression,and the odds ratio(OR)and 95%confi dence interval(CI)were ***:A total of 178(2.6%)of the 6,820 women were diagnosed with HDP,of which 126(1.8%)were GH and 52(0.8%)were ***,we found no association between PA in early pregnancy and PE.A trend toward lower risk was found only among women with GH and among those with higher levels of moderate-to-vigorous intensity physical activity(MVPA)(adjusted OR 0.54,95%CI 0.31–0.96).No association was observed between PA and HDP in early pregnancy,regardless of diff erent intensities or types of ***:MVPA in the first trimester is an influencing factor of *** pregnant women to engage in MVPA in the fi rst trimester may help to prevent GH.

关键词： Physical activity Gestational hypertension Preeclampsia Prospective cohort study

Gradient sparsification for efficient wireless federated learning with differential privacy

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Science China(Information Sciences) 2024年第4期67卷 272-288页

作者： Kang WEI Jun LI chuan MA Ming DING Feng SHU Haitao ZHAO Wen CHEN Hongbo zhu School of Electronic and Optical Engineering Nanjing University of Science and Technology Zhejiang Lab Key Laboratory of Computer Network and Information Integration(Southeast University) Ministry of Education Data61 Commonwealth Scientific and Industrial Research Organisation School of Information and Communication Engineering Hainan University School of Communications and Information Engineering Nanjing University of Posts and Telecommunications School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

Federated learning(FL) enables distributed clients to collaboratively train a machine learning model without sharing raw data with each other. However, it suffers from the leakage of private information from uploading models. In addition, as the model size grows, the training latency increases due to the limited transmission bandwidth and model performance degradation while using differential privacy(DP)protection. In this paper, we propose a gradient sparsification empowered FL framework with DP over wireless channels, to improve training efficiency without sacrificing convergence performance. Specifically, we first design a random sparsification algorithm to retain a fraction of the gradient elements in each client’s local model, thereby mitigating the performance degradation induced by DP and reducing the number of transmission parameters over wireless channels. Then, we analyze the convergence bound of the proposed algorithm, by modeling a non-convex FL problem. Next, we formulate a time-sequential stochastic optimization problem for minimizing the developed convergence bound, under the constraints of transmit power, the average transmitting delay, as well as the client’s DP requirement. Utilizing the Lyapunov drift-plus-penalty framework, we develop an analytical solution to the optimization problem. Extensive experiments have been implemented on three real-life datasets to demonstrate the effectiveness of our proposed algorithm. We show that our proposed algorithms can fully exploit the interworking between communication and computation to outperform the baselines, i.e., random scheduling, round robin, and delay-minimization algorithms.

关键词： federated learning differential privacy gradient sparsification Lyapunov drift convergence analysis

Activity-Dependent Phosphorylation of CDKL5 at Serine 407 Regulates Synaptogenesis and Plasticity

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Neuroscience Bulletin 2023年第9期39卷 1454-1458页

作者： Mengying Jiang Qiwu Xu Can Yang Dan Li Ji-Wei Liu Yuxian Zhang Yong-chuan zhu Zhi-Qi Xiong Institute of Neuroscience State Key Laboratory of NeuroscienceCAS Center for Excellence in Brain Science and Intelligence TechnologyChinese Academy of SciencesShanghai200031China University of Chinese Academy of Sciences Beijing100049China Shanghai Mental Health Center Shanghai Jiao Tong University School of MedicineShanghai200030China Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology Shanghai201210China School of Life Science and Technology ShanghaiTech UniversityShanghai201210China

Dear Editor,The X-linked gene cyclin-dependent kinase-like 5(CDKL5)encodes a serine/threonine kinase that is associated with CDKL5-deficiency disorder(CDD),a severe developmental and epileptic encephalopathy characterized by early-onset seizures,gross developmental delay,and motor disabilities[1].The expression of CDKL5 is highly enriched in the brain and is significantly induced during postnatal development[2].

关键词： seizures enriched CDK