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Microstructure and Hot Tearing Sensitivity Simulation and Parameters Optimization for the Centrifugal Casting of Al-Cu Alloy

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Computers, Materials & Continua 2024年第8期80卷 2873-2895页

作者： xueli he Shengkun Lv Ruifeng Dou Yanying Zhang Junsheng Wang Xunliang Liu Zhi Wen School of Energy and Environmental Engineering(SEEE) University of Science and Technology Beijing(USTB)Beijing100083China Advanced Research Institute of Multidisciplinary Science(ARIM) Beijing Institute of Technology(BIT)Beijing100081China

Four typical theories on the formation of thermal tears:strength,liquid film,intergranular bridging,and solidifica-tion shrinkage compensation *** these theories,a number of criteria have been derived for predicting the formation of thermal cracks,such as the stress-based Niyama,Clyne,and RDG(Rapaz-Dreiser-Grimaud)*** this paper,a mathematical model of horizontal centrifugal casting was established,and numerical simulation analysis was conducted for the centrifugal casting process of cylindrical Al-Cu alloy castings to investigate the effect of the centrifugal casting process conditions on the microstructure and hot tearing sensitivity of alloy castings by using the modified RDG hot tearing *** show that increasing the centrifugal rotation and pouring speeds can refine the microstructure of the alloy but increasing the pouring and mold preheating temperatures can lead to an increase in grain *** grain size gradually transitions from fine grain on the outer layer to coarse grain on the inner ***,combined with the modified RDG hot tearing criterion,the overall distribution of the castings’hot tearing sensitivity was *** analysis results indicate that the porosity in the middle region of the casting was large,and hot tearing defects were prone to *** hot tearing tendency on the inner side of the casting was greater than that on the outer *** effects of centrifugal rotation speed,pouring temperature,and preheating temperature on the thermal sensitivity of Al-Cu alloy castings are summarized in this *** study revealed that the tendency of alloy hot cracking decreases with the increase of the centrifugal speed,and the maximum porosity of castings decreases first and then increases with the pouring *** the preheating temperature increases,the overall maximum porosity of castings shows a decreasing trend.

关键词： Centrifugal casting Al-Cu alloy microstructure hot tearing simulation

莫妮卡的生与逝——奥古斯丁《忏悔录》中的人伦反思

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宗教学研究 2024年第3期 181-188页

作者：何雪丽北京大学哲学系

在奥古斯丁的《忏悔录》中,“我”的母亲莫妮卡是一位颇为重要又耐人寻味的人物。奥古斯丁不但时常追忆母亲的往事,而且在第9卷中用相当篇幅回顾了母亲的生平,并讲述了母亲的离世。对书中有关莫妮卡生与逝的内容的分析表明,奥古斯丁笔... 详细信息

在奥古斯丁的《忏悔录》中,“我”的母亲莫妮卡是一位颇为重要又耐人寻味的人物。奥古斯丁不但时常追忆母亲的往事,而且在第9卷中用相当篇幅回顾了母亲的生平,并讲述了母亲的离世。对书中有关莫妮卡生与逝的内容的分析表明,奥古斯丁笔下关于莫妮卡看似日常琐碎的记述,实际上承载着他对家庭亲情与自然人伦的深刻反思,构成其基督教思想不可或缺的一部分。对莫妮卡形象及母子之情的深入探究,不仅可以帮助我们更好地理解身为基督徒的奥古斯丁对待尘世人伦关系的复杂态度,更使我们得以在基督教传统拒斥“自然”的主流思想路径外,仍然看到其安顿自然人伦的努力。

关键词：奥古斯丁人伦关系基督教传统《忏悔录》基督教思想复杂态度基督徒思想路径

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肃南县畜间布鲁氏菌病流行病学调查报告

畜牧兽医杂志 2024年第2期43卷 88-90页

作者：贺雪丽肃南县动物疫病预防控制中心甘肃肃南734400

布鲁氏菌病是由布鲁氏菌属细菌引起的多种动物的、急性或慢性的人畜共患传染病。肃南县是畜间布鲁氏菌病防控二类区,为分析县内局部地方畜间布病反弹的原因,县乡两级畜牧兽医部门专题开展了畜间布鲁氏菌病疫源调查和流行病学分析,初步... 详细信息

布鲁氏菌病是由布鲁氏菌属细菌引起的多种动物的、急性或慢性的人畜共患传染病。肃南县是畜间布鲁氏菌病防控二类区,为分析县内局部地方畜间布病反弹的原因,县乡两级畜牧兽医部门专题开展了畜间布鲁氏菌病疫源调查和流行病学分析,初步摸清了布鲁氏菌病反弹的主要原因,为进一步开展好畜间布病防控工作提出了切实可行的的建议。

关键词：布鲁氏菌病流行病学调查报告

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黄河中下游河水及沉积物花粉分布与传输特征

地理学报 2024年第5期79卷 1246-1264页

作者：刘德新潘燕芳何雪莉吴朋飞马建华谷蕾河南大学地理与环境学院开封475004 河南大学黄河中下游数字地理技术教育部重点实验室开封475004 河南大学黄河文明与可持续发展研究中心开封475001

厘清河流花粉现代过程是重建流域古环境的基础。尽管学界较早开展了河水花粉研究,但花粉进入河流之后如何传输、受何种动力影响等问题尚不清楚。本文选取黄河中下游干、支流布设采样断面,在丰水期采集河水和沉积物样品开展花粉分析,采... 详细信息

厘清河流花粉现代过程是重建流域古环境的基础。尽管学界较早开展了河水花粉研究,但花粉进入河流之后如何传输、受何种动力影响等问题尚不清楚。本文选取黄河中下游干、支流布设采样断面,在丰水期采集河水和沉积物样品开展花粉分析,采用地理探测器等研究方法,探究花粉分布特征及影响因素。结果表明:(1)不同流域植被组成不同,花粉类型百分比和浓度存在较大差异,河水干流花粉浓度大于支流,而沉积物花粉百分含量与浓度干流普遍低于支流。(2)悬浮物浓度是影响河水花粉含量的主要因素,且在晋陕峡谷之外的样点表现尤为突出;粗沙多、流速快可能是导致晋陕峡谷干流悬浮物浓度高而花粉浓度低的原因。(3)黏粒含量是影响沉积物花粉含量的主要因素,且黏粒分别和粉砂、流速交互作用的影响更为突出;黄河出晋陕峡谷后沉积物花粉含量明显增加。(4)水库前后河水和沉积物花粉浓度变化分别与悬浮物和黏粒一致,相较于水样,水库后沉积物花粉浓度减少更为明显。(5)河流花粉与表土花粉有良好的对应关系,能较好的反映流域整体植被面貌。研究结果可为利用冲积物或者有河流注入的湖泊花粉开展古环境重建提供支撑。

关键词：河水花粉沉积物花粉空间分布传输机制黄河中下游

Development of a Percentile Based Three-dimensional Model of the Buttocks in Computer System

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Chinese Journal of Mechanical Engineering 2016年第3期29卷 633-640页

作者： WANG Lijing he xueli LI Hongpeng Fundamental Science on Ergonomics and Environment Control Laboratory Beihang University

There are diverse products related to human buttocks, which need to be designed, manufactured and evaluated with 3D buttock model. The 3D buttock model used in present research field is just simple approximate model similar to human buttocks. The 3D buttock percentile model is highly desired in the ergonomics design and evaluation for these products. So far, there is no research on the percentile sizing system of human 3D buttock model. So the purpose of this paper is to develop a new method for building three-dimensional buttock percentile model in computer system. After scanning the 3D shape of buttocks, the cloud data of 3D points is imported into the reverse engineering software（Geomagic） for the reconstructing of the buttock surface model. Five characteristic dimensions of the buttock are measured through mark-points after models being imported into engineering software CATIA. A series of space points are obtained by the intersecting of the cutting slices and 3D buttock surface model, and then are ordered based on the sequence number of the horizontal and vertical slices. The 1st, 5th, 50 th, 95 th, 99 th percentile values of the five dimensions and the spatial coordinate values of the space points are obtained, and used to reconstruct percentile buttock models. This research proposes a establishing method of percentile sizing system of buttock 3D model based on the percentile values of the ischial tuberosities diameter, the distances from margin to ischial tuberosity and the space coordinates value of coordinate points, for establishing the Nth percentile 3D buttock model and every special buttock types model. The proposed method also serves as a useful guidance for the other 3D percentile models establishment for other part in human body with characteristic points.

关键词： three-dimensional percentile buttock model point-cloud

欣母沛配合改良B-lynch缝合在前置胎盘剖宫产产后出血的应用

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现代科学仪器 2024年第4期41卷 107-111页

作者：何雪丽李伟苏璿淮南东方医院集团总医院

目的:观察欣母沛配合改良B-lynch缝合术在前置胎盘剖宫产产后出血的效果。方法:回顾性分析2021.1~2023.9本院收治的前置胎盘剖宫产产后出血患者资料,根据使用药物的不同分为对照组(缩宫素配合改良B-lynch缝合)和观察组(加用欣母沛),比... 详细信息

目的:观察欣母沛配合改良B-lynch缝合术在前置胎盘剖宫产产后出血的效果。方法:回顾性分析2021.1~2023.9本院收治的前置胎盘剖宫产产后出血患者资料,根据使用药物的不同分为对照组(缩宫素配合改良B-lynch缝合)和观察组(加用欣母沛),比较两组临床效果。结果:观察组止血、住院时间、术后凝血功能指标均短于对照组(P<0.05),出血量、宫底下降高度、子宫三径之和在组间、时间点及交互比较,差异均有统计学意义(P<0.05)。结论:欣母沛联合改良B-lynch缝合及缩宫素可有效控制前置胎盘剖宫产产后出血,促进子宫复旧,适于临床应用。

关键词：前置胎盘剖宫产产后出血改良B-lynch缝合术欣母沛子宫复旧

Arbuscular mycorrhizal fungi associated with the clonal plants in Mu Us sandland of China

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Progress in Natural Science:Materials International 2007年第11期17卷 1296-1302页

作者： Zhao Jinli and he xueli(College of Life Sciences, hebei University, Baoding 071002, China) College of Life Sciences Hebei University Baoding 071002 China

Clonal plants in Mu Us sandland change the sandy enviroment. The clonal plant is a kind of resource in restoration of the Mu Us sandy landscape. Soil samples at depth of 50 cm in the rhizosphere of the clonal plants were collected in 4 replicates at each location and divided into sections corresponding to 0—10, 10—20, 20—30, 30—40 and 40—50 cm depths in two representative sites from north to south in Mu Us sandland, northwestern China, in July 2005. Clonal plants included Psammochloa villosa and hedysarum laeve. The colonization and ecological distribution of arbuscular mycorrhizal (AM) fungi were investigated in the rhizosphere of clonal plants in Mu Us sandland. The results showed that the clonal plants established well symbiosis with AM fungi; AM fungal species and spatial distribution were significantly related with the host plants and soil factors. Of 16 AM fungal taxa in three genera isolated and identified, Glomus multicaule was only observed in the rhizosphere of Psammochloa villosa; Glomus aggregatum, Glomus hydembadensis, Glomus constrictum and Acaulospora rehmii only appeared in the rhizosphere of hedysarum leave. The depth of soil layers observably affected the spore density and the frequency of colonization (%F). The maximal %F and spore density occurred in the 10—20 cm layer at the site of Ordos Sandy Land Ecological Station, but which occurred in the 0—10 cm layer in Shanxi Yulin Rare Sandy-plants Conversation Field. AM fungal status and colonization might be used to monitor desertification and soil degradation.

关键词： AM fungi clonal plants Mu Us sandland

步进底加热炉三维瞬态加热过程数学模型与验证

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冶金能源 2024年第5期43卷 17-22页

作者：何雪莉李栋豆瑞锋梁敬斌尤晓东尹海清刘训良北京科技大学能源与环境工程学院北京科技大学钢铁共性技术协同创新中心河冶科技股份有限公司

以步进底加热炉炉内钢坯瞬态传热过程为研究对象,综合考虑钢坯、步进底、炉衬、炉气等之间的相互影响,建立了炉内钢坯的三维瞬态传热模型。采用黑匣子实验对模型进行验证表明,该模型能够准确预测加热过程中钢坯内部的温度水平以及变化规... 详细信息

以步进底加热炉炉内钢坯瞬态传热过程为研究对象,综合考虑钢坯、步进底、炉衬、炉气等之间的相互影响,建立了炉内钢坯的三维瞬态传热模型。采用黑匣子实验对模型进行验证表明,该模型能够准确预测加热过程中钢坯内部的温度水平以及变化规律,模型预测精度在6%以内的命中率在80%以上,为今后的工艺优化提供了理论指导。

关键词：步进底加热炉辐射传热数学模型黑匣子实验

In-situ construction of abundant active centers on hierarchically porous carbon electrode toward high-performance phosphate electrosorption: Synergistic effect of electric field and capture sites

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Green Energy & Environment 2024年第1期9卷 126-137页

作者： Peng Zhang Fukuan Li Mingming he Silu Huo xueli Zhang Benqiang Cen Dezhi Fang Kexun Li Hao Wang College of Environmental Science and Engineering Nankai UniversityTianjin300350China MOE Key Laboratory of Pollution Processes and Environmental Criteria Tianjin Key Laboratory of Environmental Remediation and Pollution ControlTianjin Key Laboratory of Environmental Technology for Complex Trans-Media PollutionNankai UniversityTianjin300350China State Key Laboratory of Simulation and Regulation of Water Cycles in River Basins China Institute of Water Resources and Hydropower ResearchBeijing100038China

Phosphate removal is crucial for eutrophication control and water quality ***-assisted adsorption,an eco-friendly elec-trosorption process,exhibited a promising potential for wastewater ***,there are few works focused on phosphate electro-sorption,and reported electrodes cannot attach satisfactory removal capacities and ***,electro-assisted adsorption of phosphate via in-situ construction of La active centers on hierarchically porous carbon(LaPC)has been originally *** resulted LaPC composite not only possessed a hierarchically porous structure with uniformly dispersed La active sites,but also provided good conductivity for interfacial electron *** LaPC electrode achieved an ultrahigh phosphate electrosorption capability of 462.01 mg g^(-1) at 1 V,outperforming most existing *** superior phosphate removal performance originates from abundant active centers formed by the coupling of electricﬁeld and capture ***,the stability and selectivity toward phosphate capture were maintained well even under comprehensive ***,a series of kinetics and isotherms models were employed to validate the electrosorption *** work demonstrates a deep understanding and promotes a new level of phosphate electrosorption.

关键词： Electro-assisted adsorption Electrosorption Phosphate removal Active centers MOF-derived carbon