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Influence of layer thickness on formation quality,microstructure,mechanical properties,and corrosion resistance of WE43 magnesium alloy fabricated by laser powder bed fusion

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Journal of Magnesium and Alloys 2024年第4期12卷 1367-1385页

作者： Bangzhao Yin Jinge Liu Bo Peng Mengran Zhou Bingchuan Liu Xiaolin Ma caimei wang Peng Wen Yun Tian Yufeng Zheng State Key Laboratory of Tribology in Advanced Equipment Beijing100084China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Institute for Precision Medicine Tsinghua UniversityBeijing102218China Department of Orthopaedics Peking University Third HospitalBeijing 100191China Beijing AKEC Medical Co. Ltd.Beijing 102200China School of Materials Science and Engineering Peking UniversityBeijing 100871China Engineering Research Center of Bone and Joint Precision Medicine Ministry of EducationBeijing 100191China

Laser powder bed fusion(L-PBF)of Mg alloys has provided tremendous opportunities for customized production of aeronautical and medical *** thickness(LT)is of great significance to the L-PBF process but has not been studied for Mg *** this study,WE43 Mg alloy bulk cubes,porous scaffolds,and thin walls with layer thicknesses of 10,20,30,and 40μm were *** required laser energy input increased with increasing layer thickness and was different for the bulk cubes and porous *** tended to occur at the connection joints in porous scaffolds for LT40 and could be eliminated by reducing the laser energy *** thin wall parts,a large overhang angle or a small wall thickness resulted in porosity when a large layer thicknesses was used,and the porosity disappeared by reducing the layer thickness or laser energy input.A deeper keyhole penetration was found in all occasions with porosity,explaining the influence of layer thickness,geometrical structure,and laser energy input on the *** the samples achieved a high fusion quality with a relative density of over 99.5%using the optimized laser energy *** increased layer thickness resulted to more precipitation phases,finer grain sizes and decreased grain *** the similar high fusion quality,the tensile strength and elongation of bulk samples were significantly improved from 257 MPa and 1.41%with the 10μm layer to 287 MPa and 15.12%with the 40μm layer,in accordance with the microstructural *** effect of layer thickness on the compressive properties of porous scaffolds was ***,the corrosion rate of bulk samples accelerated with increasing the layer thickness,mainly attributed to the increased number of precipitation phases.

关键词： Magnesium alloy WE43 Laser powder bed fusion Layer thickness Process optimization

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Improving corrosion resistance of additively manufactured WE43 magnesium alloy by high temperature oxidation for biodegradable applications

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Journal of Magnesium and Alloys 2024年第3期12卷 940-953页

作者： Jinge Liu Bangzhao Yin Fei Song Bingchuan Liu Bo Peng Peng Wen Yun Tian Yufeng Zheng Xiaolin Ma caimei wang State Key Laboratory of Tribology in Advanced Equipment Beijing100084China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China Department of Orthopaedics Beijing Tsinghua Changgung HospitalInstitute for Precision MedicineTsinghua UniversityBeijing102218China Department of Orthopaedics Peking University Third HospitalBeijing 100191China Engineering Research Center of Bone and Joint Precision Medicine Ministry of EducationBeijing 100191China School of Materials Science and Engineering Peking UniversityBeijing 100871China Beijing AKEC Medical Co. Ltd.Beijing 102200China

Laser powder bed fusion(L-PBF)has been employed to additively manufacture WE43 magnesium(Mg)alloy biodegradable implants,but WE43 L-PBF samples exhibit excessively rapid *** this work,dense WE43 L-PBF samples were built with the relativity density reaching 99.9%.High temperature oxidation was performed on the L-PBF samples in circulating air via various heating temperatures and holding *** oxidation and diffusion at the elevated temperature generated a gradient structure composed of an oxide layer at the surface,a transition layer in the middle and the *** oxide layer consisted of rare earth(RE)oxides,and became dense and thick with increasing the holding *** matrix was composed ofα-Mg,RE oxides and Mg_(24)RE_(5) *** precipitates almost disappeared in the transition *** passivation effect was observed in the samples treated by a suitable high temperature *** original L-PBF samples lost 40%weight after 3-day immersion in Hank’s solution,and broke into fragments after 7-day *** casted and solution treated samples lost roughly half of the weight after 28-day *** high temperature oxidation samples,which were heated at 525℃ for 8 h,kept the structural integrity,and lost only 6.88%weight after 28-day *** substantially improved corrosion resistance was contributed to the gradient structure at the *** one hand,the outmost dense layer of RE oxides isolated the corrosive medium;on the other hand,the transition layer considerably inhibited the corrosion owing to the lack of ***,high temperature oxidation provides an efficient,economic and safe approach to inhibit the corrosion of WE43 L-PBF samples,and has promising prospects for future clinical applications.

关键词： Laser powder bed fusion Biodegradable magnesium alloy High temperature oxidation Corrosion resistance WE43.

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Chinese Journal of Electronics 2017年第1期26卷 22-26页

作者： GONG Xudong wang caimei XIONG Yan HUANG Wenchao School of Computer Science University of Science and Technology of China Department of Computer Science Hefei University

Similar time series searching plays an important role in applications such as time series classification and outlier detection. We observe that different segment of a time series may have different significance, thus propose to assign different weight to each segment, and extract those segments with highest weights for distance computation. Since these segments are more representative, we can achieve high accuracy of similarity search with much lower computation overhead. The result of experiments on both real world and synthetic data sets demonstrates that we can achieve comparable or even higher accuracy while largely reduce the computation overhead, if we use only those important segments rather than the whole time series while performing similarity search.

关键词： Similarity search Time series Algorithm

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热带海洋大气条件下2219铝合金FSW接头力学性能研究

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热加工工艺 2024年第7期53卷 28-30,36页

作者：胡启达张华王彩妹张健刘德博北京石油化工学院机械工程学院北京102617 北京宇航系统工程研究所北京100076

对8 mm厚的2219铝合金板进行了搅拌摩擦焊试验,在热带海洋大气条件下对接头表面进行暴露试验,并结合扫描电镜(SEM)、万能拉伸试验机等研究了不同暴露时间下2219铝合金搅拌摩擦焊接头的腐蚀形貌和力学性能。结果表明,随着暴露时间的延长... 详细信息

对8 mm厚的2219铝合金板进行了搅拌摩擦焊试验,在热带海洋大气条件下对接头表面进行暴露试验,并结合扫描电镜(SEM)、万能拉伸试验机等研究了不同暴露时间下2219铝合金搅拌摩擦焊接头的腐蚀形貌和力学性能。结果表明,随着暴露时间的延长,接头的拉伸性能降低,暴露3月后接头抗拉强度为400 MPa,断后伸长率为17.53%,暴露12月后抗拉强度下降到363.25 MPa,断后伸长率下降到15.9%;断裂形式由韧性断裂发展为局部脆性断裂,最终发展为大部分脆性断裂。

关键词：热带海洋大气 2219铝合金搅拌摩擦焊腐蚀力学性能

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电感耦合等离子体-质谱法测定枸橼酸三乙酯中7种元素杂质

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中国药业 2024年第3期33卷 88-91页

作者：王彩媚林嗣翔王淼广东省药品检验所·国家药品监督管理局药用辅料质量控制与评价重点实验室广东广州510663

目的建立测定枸橼酸三乙酯中镉(Cd)、铅(Pb)、砷(As)、汞(Hg)、钴(Co)、钒(V)、镍(Ni)7种元素杂质残留量的电感耦合等离子体-质谱法。方法采用在线内标法,载气为氦气,等离子体模式为HMI-8,载气、雾化气、辅助气流量均为0.8 L/min,等离... 详细信息

目的建立测定枸橼酸三乙酯中镉(Cd)、铅(Pb)、砷(As)、汞(Hg)、钴(Co)、钒(V)、镍(Ni)7种元素杂质残留量的电感耦合等离子体-质谱法。方法采用在线内标法,载气为氦气,等离子体模式为HMI-8,载气、雾化气、辅助气流量均为0.8 L/min,等离子气流量为15.0 L/min,蠕动泵转速为0.10 r/min,雾化室温度为2℃。结果V,Co,Ni,As,Cd,Pb元素的质量浓度在0~20.0 ng/mL范围内,Hg元素的质量浓度在0~5.0 ng/mL范围内,与仪器响应值线性关系良好(r≥0.9995,n=7);精密度试验结果的RSD均小于3%(n=6);加样回收率分别为97.58%,96.12%,96.56%,100.25%,96.63%,99.80%,106.73%,RSD分别为1.11%,1.29%,2.43%,1.09%,0.89%,1.26%,4.48%(n=9)。23批样品中7种元素杂质含量均低于控制阈值。结论该方法操作简便、精密度好、结果准确,可用于枸橼酸三乙酯中痕量元素杂质的含量测定。

关键词：枸橼酸三乙酯电感耦合等离子体-质谱法元素杂质

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Effect of Phase Structure Evolution on Thermal Expansion and Toughness of (Nd1-xScx)2Zr2O7 (x = 0, 0.025, 0.05, 0.075, 0.1 ) Ceramics

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Journal of Materials Science & Technology 2017年第2期33卷 192-197页

作者： Xiaoxiang Zhao Lei Guo caimei wang Yu Zhang Fuxing Ye School of Materials Science and Engineering Tianjin University Tianjin 300072 China Tianjin Key Laboratory of Advanced Joining Technology Tianjin University Tianjin 300072 China Key Lab of Advanced Ceramics and Machining Technology of Ministry of Education Tianjin University Tianjin 300072 China

Nd2Zr2O7 is being explored as an alternate thermal barrier coating （TBC） material for operating above 1300 ℃, and great effort has been made to enlarge its thermal expansion coefficient （TEC） and improve its toughness. In this study, Sc203 vvas doped to Nd2Zr2O7. The phase structure, TECs and toughness of （Nd1-xScx）2Zr2O7 （x = 0, 0.025, 0.05, 0.075, 0.1 ） compounds were investigated. （Nd1-xScx）2Zr2O7 （x = 0, 0.025, 0.05, 0,075） exhibited pyrochlore structure, while （Nd0.9Sc0.1）2Zr2O7 consisted of pyrochlore and fluorite phases. With the increase of the Sc203 content, the ordering degree of the pyrochlore in the compounds decreased. In （Nd1-xScx）2Zr2O7 series, （Nd0.925Sc0.075）2Zr2O7 exhibited the largest TEC, while the toughness of the compounds increased with increasing the Sc2O3 content. The related mechanisms were discussed based on the crystal structure analysis. Considering the TEC and toughness, 10 mol% Sc2O3 was sug- gested as the optimal doping content for Nd2Zr2O7 ceramic.

关键词： Thermal harrier coating Nd2Zr2O7 Doping Phase structure Thermal expansion coefficient Toughness

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面向去中心化存储的数据流行度去重模型

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计算机应用研究 2024年第5期41卷 1544-1553页

作者：汪彩梅闻琪略周子健卢建豪张琛吴志泽合肥大学人工智能与大数据学院合肥230601

数据流行度去重方案中存在检测机构不诚实、数据存储不可靠等问题,提出一种面向去中心化存储的数据流行度去重模型。针对检测机构不诚实,模型结合区块链的不可窜改性与智能合约的不可抵赖性,将智能合约作为检测机构执行数据的重复性检... 详细信息

数据流行度去重方案中存在检测机构不诚实、数据存储不可靠等问题,提出一种面向去中心化存储的数据流行度去重模型。针对检测机构不诚实,模型结合区块链的不可窜改性与智能合约的不可抵赖性,将智能合约作为检测机构执行数据的重复性检测和流行度检测,保障了检测结果的真实性。针对数据存储不可靠问题,提出一种文件链存储结构。该结构满足数据流行度去重的要求,并通过添加辅助信息的方式,建立分布在不同存储节点中实现物理/逻辑上传的分片之间的逻辑关系,为流行度数据去中心化网络存储提供基础;同时,在数据块信息中添加备份标识,借助备份标识将存储网络划分为两个虚拟存储空间,分别实现数据和备份数据的检测与存储,满足了用户备份需求。安全性分析和性能分析表明,该方案具有可行性,保障了检测结果的真实性,并提高了数据存储的可靠性。

关键词：数据去重数据流行度去中心化区块链存储可靠性

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Personalized Privacy-Preserving Trajectory Data Publishing

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Chinese Journal of Electronics 2017年第2期26卷 285-291页

作者： LU Qiwei wang caimei XIONG Yan XIA Huihua HUANG Wenchao GONG Xudong School of Computer Science and Technology University of Science and Technology of China Department of Computer Science and Engineering Hefei University

Due to the popularity of mobile internet and location-aware devices,there is an explosion of location and tra jectory data of moving objects.A few proposals have been proposed for privacy preserving tra jectory data publishing,and most of them assume the attacks with the same adversarial background *** practice,different users have different privacy *** non-personalized privacy assumption does not meet the personalized privacy requirements,meanwhile,it looses the chance to achieve better utility by taking advantage of differences of users’ privacy *** study the personalized tra jectory k-anonymity criterion for trajectory data ***,we explore and propose an overall framework which provides privacy preserving services based on users’ personal privacy requests,including tra jectory clustering,editing and *** demonstrate the efficiency and effectiveness of our scheme through experiments on real world dataset.

关键词： Personalization Tra jectory data Privacy-preserving data publishing

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乌拉地尔联合硫酸镁、阿司匹林治疗妊娠期高血压疾病的效果及对微环境炎症的影响

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临床医学研究与实践 2024年第1期9卷 124-127,136页

作者：王彩梅刘继梅寇帅榆林市第二医院陕西榆林719000

目的分析乌拉地尔联合硫酸镁、阿司匹林治疗妊娠期高血压疾病的效果及对微环境炎症的影响。方法选择2021年1月至2022年3月我院收治的80例妊娠期高血压疾病患者作为研究对象,以随机数字表法将其分为对照组和观察组,每组40例。对照组给予... 详细信息

目的分析乌拉地尔联合硫酸镁、阿司匹林治疗妊娠期高血压疾病的效果及对微环境炎症的影响。方法选择2021年1月至2022年3月我院收治的80例妊娠期高血压疾病患者作为研究对象,以随机数字表法将其分为对照组和观察组,每组40例。对照组给予硫酸镁、阿司匹林治疗,观察组在对照组治疗基础上加施乌拉地尔治疗。比较两组的治疗效果。结果治疗后,观察组的收缩压、舒张压、尿蛋白含量低于对照组(P<0.05)。治疗后,观察组的可溶性白细胞介素-2受体(sIL-2R)、核因子-κB(NF-κB)、高迁移率族蛋白B1(HMGB1)水平低于对照组(P<0.05)。治疗后,观察组的内皮素-1(ET-1)水平低于对照组,血管内皮生长因子(VEGF)、血小板内皮细胞黏附分子-1(PECAM-1)水平高于对照组(P<0.05)。观察组的不良妊娠总发生率显著低于对照组(P<0.05)。结论乌拉地尔联合硫酸镁、阿司匹林治疗妊娠期高血压疾病不仅能改善微环境炎症及血管内皮功能,提高血压控制效果,还能减少不良妊娠结局发生,值得临床进一步推广及应用。

关键词：乌拉地尔硫酸镁阿司匹林妊娠期高血压疾病微环境炎症妊娠结局

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药用辅料糊精的质量评价

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华西药学杂志 2024年第2期39卷 193-196页

作者：叶秀金胡淑君李艺郭雅娟胡佳哲王彩媚林嗣翔陈旻广东省药品检验所国家药品监督管理局药用辅料质量控制与评价重点实验室广东广州510663

目的考察药用辅料糊精的质量现状及存在问题。方法按现行质量标准,对18个厂家167批样品进行检验,并开展探索性试验,分析评价糊精的质量。结果按现行标准检验,1批样品不合格。产品中真菌毒素的含量较高,并存在质量不均一的情况,应重视,... 详细信息

目的考察药用辅料糊精的质量现状及存在问题。方法按现行质量标准,对18个厂家167批样品进行检验,并开展探索性试验,分析评价糊精的质量。结果按现行标准检验,1批样品不合格。产品中真菌毒素的含量较高,并存在质量不均一的情况,应重视,以免带来质量风险。结论按现行质量标准和探索性研究项目检验,糊精的合格率为85.6%。为后续制剂研究提供参考,对中药制剂的发展具重要意义。

关键词：糊精质量评价均匀性真菌毒素溶液的澄清度元素杂质还原糖农药残留

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