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Inlet Recirculation Influence to the Flow Structure of Centrifugal Impeller

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Chinese Journal of Mechanical Engineering 2010年第5期23卷 647-654页

作者： YANG Ce CHEN shan LI Du YANG Changmao wang Yidi School of Mechanical Engineering Beijing Institute of Technology Beijing 100081 China Hunan TYENMachinery Co. Ltd. Hengyang 421005 China

Inlet recirculation is proved as an effective way for centrifugal compressor surge margin extension,and is successively used in some engineering *** its working mechanism is still not being well understood,which leads to redesigning of inlet recirculation mostly by ***,most study about inlet recirculation is steady to *** is necessary to study surge margin extension mechanism about inlet *** expose the mechanism in detail,steady and unsteady numerical simulations were performed on a centrifugal compressor with and without inlet *** results showed that,with inlet recirculation,the inlet axial velocity is augmented,relative Mach number around blade tip leading edge area is significantly reduced and so is the flow *** the flow angle decreased,the incidence angle reduced which greatly improves the flow field inside the ***,inlet recirculation changes the blade loading around blade tip and restrains the flow separation on the blade suction side at the leading edge *** unsteady results of static pressure around blade surface,entropy at inlet crossflow section and vorticity distributions at near tip span surface indicated that,at near stall condition,strong fluctuation exists in the vicinity of tip area due to the interaction between tip leakage flow and core *** inlet recirculation these strong flow fluctuations are eliminated so the flow stability is greatly *** these improvements mentioned above are the reason for inlet recirculation delays compressor *** research reveals the surge margin extension reason of inlet recirculation from an unsteady flow viewpoint and provides important reference for inlet recirculation structure design.

关键词： centrifugal compressor inlet recirculation flow field calculation flow structure unsteady

Fabrication of nanoporous silver by de-alloying Cu?Zr?Ag amorphous alloys

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International Journal of Minerals,Metallurgy and Materials 2016年第7期23卷 835-843页

作者： hui wang shang-gang Xiao Tao Zhang School of Materials Science and Engineering Beihang University Key Laboratory of Aerospace Materials and Performance (Ministry of Education) Beihang University

Nanoporous silver（NPS） with a ligament size ranging from 15 to 40 nm was fabricated by de-alloying（Cu_（50）Zr_（50））_（100-x）Agx（x = 10at%, 20at%, 30at%, and 40at%） amorphous ribbons in a mixed aqueous solution of hydrofluoric（HF） acid and nitric acid under free corrosion conditions. Nanoporous silver ligaments and pore sizes were able to be fine-tuned through tailoring the chemical composition, corrosion conditions, and de-alloying time. The ligament size increases with an increase in Ag content and de-alloying time, but decreases with an increase in HF concentration. This phenomenon may be attributed to the dissolution of Zr/Cu and the diffusion, aggregation, nucleation, and recrystallization of Ag, leading to an oriented attachment of adjacent nanocrystals as revealed by TEM analysis.

关键词： amorphous alloys corrosion silver nanopores fabrication

Corrosion behaviors of thermally grown oxide films on Fe-based bulk metallic glasses

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International Journal of Minerals,Metallurgy and Materials 2012年第8期19卷 726-732页

作者： Hong-xiang Li shan-lin wang Yeonuk Jeong Seonghoon Yi State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China. School of Aeronautical Manufacturing Engineering Nanchang Hangkong University Nanchang 330063 China. Department of Electronic Materials Science and Engineering Kyungpook National University Daegu 702-701 South Korea. Department of Materials Science and Metallurgy Kyungpook National University Daegu 702-701 South Korea.

Oxide films formed on the surfaces of Fe-based bulk metallic glasses in the temperature range between 373 K and 573 K were characterized and their effects on the corrosion behaviors were investigated by microstructural and electrochemical analysis. The oxide film formed at 573 K is iron-rich oxide and it exhibits an n-type semiconductor at a higher potential than 0.35 V and a p-type semiconductor at a lower potential than 0.35 V. Capacitance measurements show that the donor density decreases with the increase in oxidation temperature, while the thickness of the space charge layer increases with the oxidation temperature rising. The result of immersion tests shows that the mass loss rate increases with the oxidation temperature rising. Therefore, the correlation between microstructure and corrosion resistance needs to be proposed because the corrosion resistance is deteriorated with the development of the oxide films.

关键词： bulk metallic glass oxide films corrosion capacitance

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有源医疗器械使用期限研究资料常见问题分析

中国医疗器械信息 2024年第1期30卷 15-17,59页

作者：王志远吴璠黄珊珊朱静周冬安徽省药品审评查验中心安徽合肥230041

医疗器械注册申请人应保证医疗器械产品在使用期限内安全有效,并在注册申报时提交使用期限研究资料。文章汇总自2020年4月~2022年1月安徽审评中心受理的有源医疗器械注册申请件,梳理和分析使用期限研究资料的共性问题,总结使用期限研究... 详细信息

医疗器械注册申请人应保证医疗器械产品在使用期限内安全有效,并在注册申报时提交使用期限研究资料。文章汇总自2020年4月~2022年1月安徽审评中心受理的有源医疗器械注册申请件,梳理和分析使用期限研究资料的共性问题,总结使用期限研究的重难点。以期帮助申请人提高注册申报资料的完整性和合规性,提升使用期限研究的科学性和系统性,在加快医疗器械产品上市的同时保证质量可靠。

关键词：有源医疗器械使用期限研究资料技术审评

Improving multiprocessor performance with fine-grain coherence bypass

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Science China(Information Sciences) 2015年第1期58卷 84-98页

作者： wang hui wang Rui LUAN ZhongZhi QIAN XueHai QIAN DePei Sino-German Joint Software Institute School of Computer Science and EngineeringBeihang University University of Illinois Urbana-Champaign

Efficient and scalable cache coherence protocol is crucial to high-performance servers with sharedmemory. The directory-based cache coherence protocol is more desirable than the snooping-based protocol with respect to the scalability. However, even for the former protocol, scaling to a large number of cores is also challenging due to the additional area requirements of the directories. We observed that a significant percentage of the referenced memory blocks were only accessed by a single core(even in parallel applications) which could be considered as private memory blocks. An intuitive motivation from this observation is that memory blocks accessed by a single core do not require coherence maintenance. The issue is to identify the private block and track the change of its access pattern. We propose a novel hardware approach to(1) dynamically identify the shared memory blocks at the cache block level, and(2) bypass the coherence procedure for the private memory blocks. This approach increases the effectiveness of the directory-based approach and therefore improves the system performance. Experimental results showed that, our approach can on an average(1) avoid the coherence tracking of about 54% referenced memory blocks,(2) reduce the coherence overhead by 77%,(3) avoid 8% L2 cache misses, and(4) shorten the execution time of parallel applications by 13%.

关键词： many-core cache coherence private memory block fine-grain coherence high performance

Recent advances of multidimensional sensing: from design to applications

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Science China Chemistry 2019年第12期62卷 1601-1618页

作者： Sihua Qian shan Sun Yuhui wang Zhongjun Li Hengwei Lin Ningbo Institute of Materials Technology&Engineering(NIMTE) Chinese Academy of SciencesNingbo 315201China University of Chinese Academy of Sciences Beijing 100049China College of Chemistry and Molecular Engineering Zhengzhou UniversityZhengzhou 450001China

Recently,multidimensional(or multi-channel)sensing methodology has attracted broad attention in the field of analytical chemistry due to its fascinating merits.A variety of multidimensional sensors based on sensor arrays,lab-on-a-molecule/nanoparticle and smart chip strategies have been designed to differentiate chemical structure and property similar analytes and complex *** recognition algorithms are usually used and allow these sensors to fulfill such *** this review,the recent advances of multidimensional sensor devices were firstly summarized,and particularly focused on their design strategies and applications in monitoring of biological active molecules,biomarkers,microbes,foods and beverages,***,some limitations and possible solutions of multidimensional sensors were *** finally,potential applications of this technique in the future were *** review would help the readers who are interested in multidimensional sensing methodology to understand the research progresses and trends.

关键词： multidimensional sensor multi-channel sensor sensor arrays smart chip lab-on-a-molecule/nanoparticle

钻井过程储层无机垢损害的时空尺度数值模拟及应用

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科学技术与工程 2024年第3期24卷 1014-1020页

作者：苏延辉王巧智易飞熊培祺曹丹中海油能源发展股份有限公司工程技术分公司天津300452

钻井过程结无机垢现象普遍存在,由于缺乏对问题井的结无机垢损害程度、损害半径的有效判断,难以进行有效的储层保护,造成储层堵塞,完井后无法达到配产。针对于钻井过程中常见的碳酸钙、硫酸钙、硫酸钡、硫酸锶等类型无机垢损害,建立力... 详细信息

钻井过程结无机垢现象普遍存在,由于缺乏对问题井的结无机垢损害程度、损害半径的有效判断,难以进行有效的储层保护,造成储层堵塞,完井后无法达到配产。针对于钻井过程中常见的碳酸钙、硫酸钙、硫酸钡、硫酸锶等类型无机垢损害,建立力学化学耦合的微分方程组数学模型,实现无机垢损害的时空尺度模拟,模型的准确性在渤海某油田得到验证和应用。基于此模型探索钻井压差、储层温度、储层压力等模型参数对结无机垢损害程度的影响,钻井过程中的储层无机垢损害应以预防为主,合理控制钻井压差是关键。

关键词：钻井无机垢时空尺度数值模拟

铸牢中华民族共同体意识视域下促进各族学生交往交流交融的实践路径研究——以宁夏高校为例

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民族艺林 2024年第2期 46-55页

作者：惠庆王维东宁夏大学法学院宁夏银川750021 宁夏职业技术学院马克思主义学院宁夏银川750021

铸牢中华民族共同体意识是新时代党的民族工作和民族地区各项工作的主线,也是高校开展思想政治教育课程建设的重要内容。作为少数民族地区,宁夏高校坚持以民族团结进步教育活动为载体,将非物质文化遗产传承发展与专业建设、课程建设相融... 详细信息

铸牢中华民族共同体意识是新时代党的民族工作和民族地区各项工作的主线,也是高校开展思想政治教育课程建设的重要内容。作为少数民族地区,宁夏高校坚持以民族团结进步教育活动为载体,将非物质文化遗产传承发展与专业建设、课程建设相融合,在深入开展交往交流交融活动中积累了宝贵经验。通过研究各族学生交往交流交融的实践路径,探索高校持续铸牢中华民族共同体意识的优化方法,能够为加快建设铸牢中华民族共同体意识示范区贡献智慧与力量。

关键词：铸牢中华民族共同体意识民族地区交往交流交融高校

经典名方小承气汤颗粒干法制备工艺及其质量标准研究

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中国新药杂志 2024年第6期33卷 588-597页

作者：朱文杰单家明杨元丰熊豪郭文慧叶喜德杨武亮江西中医药大学现代中药制剂教育部重点实验室南昌330004

目的:优选小承气汤颗粒的干法制粒工艺,并制定其质量控制方法。方法:以颗粒一次性成型率、休止角、吸湿率及溶化性为考察指标,在单因素考察干法制粒机压片压力、辅料(糊精∶可溶性淀粉)比例和二氧化硅用量的基础上,结合正交实验,优选小... 详细信息

目的:优选小承气汤颗粒的干法制粒工艺,并制定其质量控制方法。方法:以颗粒一次性成型率、休止角、吸湿率及溶化性为考察指标,在单因素考察干法制粒机压片压力、辅料(糊精∶可溶性淀粉)比例和二氧化硅用量的基础上,结合正交实验,优选小承气汤颗粒的干法制粒最佳工艺。采用薄层色谱法(TLC)鉴别方法和高效液相色谱法(HPLC)测定小承气汤颗粒中游离蒽醌、总蒽醌(以大黄酸、大黄素、大黄酚)含量,建立其质控标准。结果:优化后的小承气汤颗粒干法制备工艺为:干膏粉∶辅料=7∶3,辅料(糊精∶可溶性淀粉=1∶1),二氧化硅用量5%,压片压力22 MPa。颗粒中大黄、厚朴和枳实饮片的TLC鉴别斑点清晰,阴性无干扰。大黄酸在36.22~362.20 ng、大黄素在36.80~368.00 ng、大黄酚在38.44~384.40 ng范围内线性关系良好(R^(2)=0.9999)。游离大黄酸、大黄素、大黄酚的平均回收率分别为98.46%,102.25%,99.02%;总大黄酸、大黄素、大黄酚的平均回收率分别为95.18%,93.84%,97.94%。结论:优选的干法制粒工艺条件稳定可行,适合规模化生产;质量控制方法简单准确,可用于小承气汤颗粒的质量控制。

关键词：小承气汤颗粒干法制粒薄层色谱法鉴别高效液相色谱法测定质量标准