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multiscale microstructural consideration of enhanced shear strength in TiAl intermetallic/K4169 alloy composite joints prepared by vacuum brazing with(Ti,Zr)-Ni-based amorphous filler metal

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Journal of materials Science & Technology 2024年第5期172卷 51-70页

作者： Liangliang Zhang Honggang Dong Peng Li Baosheng Wu Yueting ma Libing Huang Chao Li Jiachen Li School of materials Science and Engineering Dalian University of TechnologyDalian 116024China

TiAl intermetallic could be used to replace Ni-based alloy in assemblies to generate excellent specific strength.A(Ti,Zr)-Ni-based amorphous filler metal Ti_(21.25)Zr_(25)Ni_(25)Cu_(18.75)(at.%)was designed using a cluster-plus-glue-atom model to successfully vacuum braze K4169 and TiAl bimetallic *** various brazing temperatures and holding time,the quantitative relationships between lattice distortion,grain boundary,dislocation density,and hardness,elastic modulus,shear strength of the joints were ***,the fracture mechanism of the joints was *** brazed seam mainly consisted of solid diffusion reaction layers(ZonesⅠandⅢ)and filler metal residue zone(ZoneⅡ).When the brazing temperature increased to 1030℃,grain refinement occurred in the brazed ***Ⅰwas primarily composed of(Ni)ss[0-11]+TiNi[011]/(Cr,Fe,Ni)ss[0-11]/(Ti,Zr)Ni[0-1-1]+(Cr,Fe,Ni)ss[0-11].The(Ti,Zr)(Ni,Cu)[001]and(Ti,Zr)(Ni,Cu)[101]intermetallic compound-based solid solutions were formed in ZoneⅡ.And the lattice distortion of(Ti,Zr)(Ni,Cu)[101]and(Ti,Zr)(Ni,Cu)[001]was 32.05%and 14.82%,*** a result,the proportion of low angle grain boundaries(LAGBs)and deformed grains in ZoneⅡrose to 38.6%and 38.7%.in ZonesⅠandⅢ,the proportion of LAGBs reduced to 8%and 3.4%,*** the holding time increased,the long-range diffusion of Al in ZoneⅡcaused the(Ti,Zr)(Ni,Cu)[001]with cubic structure to transform into(Ti,Zr)(Ni,Cu,Al)[00-1]with hexagonal crystal system structure,where the lattice distortion was 4.42%and 10.49%for a and *** 1030℃/10 min,the average geometrically nec-essary dislocation densities(GNDs)in ZonesⅠ,ⅡandⅢwere 9.87×10^(14)m^(-2),8.55×10^(14)m^(-2)and 11.4×10^(14)m^(-2),***,the shear strength of joints reached 322 mPa due to the lattice distortion,dislocation strengthening and fine grain ***,the plastic and brittle hard phases were generated in ZoneⅡand displayed a mechanical interlocking structure tha

关键词： K4169/Ti_(21.25)Zr_(25)Ni_(25)Cu_(18.75)/TiAl composite joints intermetallic compound-based solid solution Lattice distortion Elastic modulus

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Flexible microbubble-based Fabry-Pérot cavity for sensitive ultrasound detection and wide-view photoacoustic imaging

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Photonics Research 2020年第10期8卷 1558-1565页

作者： JUN ma YANG HE XUE BAi Li-PENG SUN ka CHEN KYUNGHWAN OH BAi-OU GUAN Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Institute of Photonics TechnologyJinan UniversityGuangzhou 511443China Photonic Device Physics Laboratory Department of PhysicsYonsei UniversitySeoul 033722South Korea

interaction of acoustic waves and microbubbles occurs in numerous biomedical applications including ultrasound imaging,drug delivery,lithotripsy treatment,and cell manipulation,wherein the acoustically driven microbub-blcs routincly act as active microscale oscillators or *** contrast,microbubbles were utilized here as passive reccivers to detect broadband ultrasound waves in aqueous *** microbubble was photo-thermally generated on a microstructured optical fiber(mOF)tip,forming a flexible Fabry-Perot cavity whose gas-water interface was sensitive to ultrasound *** mOF severed as both a low-loss waveguide and a compact light condenser,allowing high-efficiency generation and stabilization of ultrasmall *** with all-fiber interferometry,a 10 um diameter microbubble exhibited a low noise-cquivalcnt pressur elevei of^3.4 mPa/Hz^1/2 and a broad bandwidth of^0.8 mHz,capable of detecting weak ultrasounds emittedfrom red blood cells irradiated by pulsed laser *** advantages of high sensitivity,compact size,and low cost,the microbubble-based ultrasound sensor has great potential in biomedical imaging and sensing applications.

关键词： microstructure bubble cavity

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济阳坳陷富有机质页岩记录的中始新世气候适宜期古气候

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第四纪研究 2024年第05期44卷 1273-1281页

作者：郭颖马义权刘惠民陆永潮张晨马超成都理工大学自然资源部深时地理环境重建与应用重点实验室成都理工大学油气藏地质及开发工程全国重点实验室成都理工大学沉积地质研究院成都理工大学管理科学学院中国石油化工股份有限公司胜利油田分公司中国地质大学(武汉)资源学院成都理工大学计算机与网络安全学院

中始新世气候适宜期(mECO)是发生在约40.5～40.1 ma的一次全球增温事件。目前该事件在海相环境中的响应特征已相对明晰，而对其发生前、发生期间、发生之后的陆相环境响应及差异的认识仍需进一步研究。济阳坳陷北部的沾化凹陷中始新统... 详细信息

中始新世气候适宜期(mECO)是发生在约40.5～40.1 ma的一次全球增温事件。目前该事件在海相环境中的响应特征已相对明晰，而对其发生前、发生期间、发生之后的陆相环境响应及差异的认识仍需进一步研究。济阳坳陷北部的沾化凹陷中始新统沙三下亚段(Es3L)为一套富有机质页岩层系，沉积连续，不仅是该区页岩油勘探的重点层位，也为开展mECO事件的陆相环境响应研究提供了详实的沉积记录。本研究利用沾化凹陷Luo69井跨越Es3L且长度约194 m的高分辨率伽马(GR)数据，开展旋回地层学分析，结合相关系数法(COCO)和演化相关系数法(eCOCO),以Es3L的底界年龄41.21 ma为锚点，建立天文年代标尺。在此基础上，综合Fe含量、 Ti/K比值、 V/Al比值、 TOC含量以及济阳坳陷南部东营凹陷的FY1井的磁性地层，确定mECO事件在研究区的响应时间，查明mECO事件发生前、发生期间、发生后济阳坳陷的气候和水文变化及其对有机质富集的影响。结果表明，Luo69井GR数据中的20.7～27.7 m波长代表405 ka长偏心率，通过调谐，获得GR数据的延续时间为3.34 ma, Es3L的延续时间为2.48 ma,与已报道的FY1井结果一致。结合年龄锚点，建立了41.77 ma至38.43 ma的天文年代标尺，并推定mECO事件在济阳坳陷的响应时间约为40.51～40.06 ma,对应于Luo69井的约3045～3017 m区间。在mECO事件发生之前，气候潮湿-干旱波动较大，引起湖盆流域水动力和湖水氧化还原状态出现较大变化；mECO期间，气候更加潮湿，使得流域水动力增强，导致湖水富氧，但该时期TOC含量整体较高，可能与较高的初级生产力有关；在mECO事件发生后，气候变化幅度较小，相对稳定，相比事件发生前更加潮湿，TOC较事件发生前略有升高，主要受控于升高的初级生产力。

关键词：增温事件统计调谐时间序列分析古气候有机质富集页岩油

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Three-dimensional reconstruction and comparison of vacuolar membranes in response to viral infection

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Journal of integrative Plant Biology 2021年第2期63卷 353-364页

作者： Xueting Wang Juncai ma Xuejiao Jin Ning Yue Peng Gao Keith ka Ki mai Xian-Bing Wang Dawei Li Byung-Ho kang Yongliang Zhang State Key Laboratory of Agro-Biotechnology and ministry of Agriculture Key Laboratory of Soil microbiology College of Biological SciencesChina Agricultural UniversityBeijing 100193China State Key Laboratory of Agro-Biotechnology School of Life SciencesThe Chinese University of Hong KongHong Kong 999077China

The vacuole is a unique plant organelle that plays an important role in maintaining cellular homeostasis under various environmental stress conditions. However, the effects of biotic stress on vacuole structure has not been examined using three-dimensional(3D) visualization. Here, we performed 3D electron tomography to compare the ultrastructural changes in the vacuole during infection with different viruses. The 3D models revealed that vacuoles are remodeled in cells infected with cucumber mosaic virus(CmV) or tobacco necrosis virus A Chinese isolate(TNV-AC), resulting in the formation of spherules at the periphery of the vacuole. These spherules contain neck-like channels that connect their interior with the cytosol. Confocal microscopy of CmV replication proteins 1 a and 2 a and TNV-AC auxiliary replication protein p23 showed that all of these proteins localize to the *** microscopy revealed that the expression of these replication proteins alone is sufficient to induce spherule formation on the tonoplast, suggesting that these proteins play prominent roles in inducing vacuolar membrane remodeling. This is the first report of the 3D structures of viral replication factories built on the tonoplasts. These findings contribute to our understanding of vacuole biogenesis under normal conditions and during assembly of plant(+) RNA virus replication complexes.

关键词： comparison cucumber mosaic virus electron tomography spherules tobacco necrosis virus A vacuole viral replication

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Dietary Calcium Decreases Plasma Cholesterol Level only in Female but not in male Hamster Fed a High Cholesterol Diet

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Biomedical and Environmental Sciences 2012年第4期25卷 392-398页

作者： ma ka Ying LiANG Yin Tong CHEN Jing Nan JiANG Yue KWAN Kin ming PENG Cheng JiAO Rui ZUO Yuan Yuan HUANG Yu CHEN Zhen Yu Food & Nutritional Sciences Programme School of Life Sciences The Chinese University of Hong Kong Shatin NT Hong Kong China Department of Biology and Kwong Living Trust Food Safety & Analysis Laboratory Hong Kong Baptist University Kowloon Tong Hong Kong China School of Biomedical Sciences The Chinese University of Hong Kong Shatin NT Hong Kong China

Objective To investigate the effect of dietary calcium on plasma lipoprotein profile in castrated and ovariectomized hamsters. methods male, castrated, female and ovariectomized hamsters （n=36 each group） were randomly divided into three sub-groups （n=12） and fed one of the three diets containing O, 2, and B g calcium per kg diet for a period of six weeks. Changes in plasma lipoprotein profile were monitored at the end of week O, 3 and 6. Results Plasma total cholesterol （TC）, non-high density lipoprotein cholesterol （non-HDL-C）, triacylglycerols （TG） and TC/HDL-C were decreased only in intact female and ovariectomized hamsters. in contrast, three levels of dietary calcium had no effect on lipoprotein profiles in both intact male and castrated hamsters. Conclusion Beneficial modification of lipoprotein profile by dietary calcium was gender-dependent at least in hamsters.

关键词： Calcium Cholesterol Triacylglycerols Fecal sterols

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泛巽他盆山体系北部湾古泥沼旋回与古生态效应

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现代地质 2024年第2期38卷 269-286页

作者：黄向青梁开马胜中袁晓婕潘毅中国地质调查局广州海洋地质调查局广东广州511458 自然资源部海底矿产资源重点实验室广东广州511458

南海西北部北部湾在地质环境方面与狭义巽他陆架相似而成为一体构成泛巽他,同属青藏高原及其挤出阶梯地貌盆山体系。然而,关于其指示环境变化和碳循环的古泥沼分布及其气候-构造驱动机制、作用与联系等缺乏关注,其研究滞后于上述热点巽... 详细信息

南海西北部北部湾在地质环境方面与狭义巽他陆架相似而成为一体构成泛巽他,同属青藏高原及其挤出阶梯地貌盆山体系。然而,关于其指示环境变化和碳循环的古泥沼分布及其气候-构造驱动机制、作用与联系等缺乏关注,其研究滞后于上述热点巽他陆架相关进展。为加强对这些内容的认识,本文的研究在北部湾北部华南陆缘沉降带进行了80.05 m进尺第四系全岩心钻取,立足于沉积物微体古生物、粒度、碎屑矿物组分、微量元素含量等基础沉积环境指标的实验测试、鉴定以及测年数据,并结合前人相关资料和结果进行综合分析。结果表明,岩心底部年龄为中更新世后期171.0 ka,孢粉化石呈热带和亚热带植被面貌,主要有栲属、栎属等以及鳞盖蕨属、水龙骨科等,其含量变化显示出3个主要气候变化阶段,与倒数第二冰盛期、末次间冰期、末次冰期以及冰消期等相联系,从56.0 ka始见有半咸水种硅藻化石条纹小环藻、柱状小环藻等,有孔虫化石出现于中全新世6.0 ka接受海进。总体上以砂为主,但局部粉砂和黏土(泥)含量较高,最高依次可达65.78%、59.71%,元素含量为2.6×10^(-6)~347×10^(-6),碎屑矿物稳定出现石英、长石、风化矿物,以前者占优,平均含量88.57%,余下矿物相间出现,具有陆源性,各要素随气候阶段而变化。存在5个泥沼旋回,沉积环境有所差异,在冰期和间冰期均有分布,出现炭化腐木以及邻区炭化层。青藏高原隆起导致的区域强烈地形落差在中—晚更新世业已构建,盆山体系成为海洋暖湿气流与地形作用的水热有效利用地带,北部湾冰期出露地表古水系广布,森林和草地植被共存,有助于泥沼的维护发展。气候波动性是泥沼的本质驱动因素,除了间冰期之外,冰期的强烈暖阶振荡亦为其成因;泛巽他北部湾在冰期同样具有碳库意义,具有转移与弥补中高纬度生产力衰减之作用。

关键词：北部湾沉积要素变化泥沼旋回驱动机制碳库

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2/3匝线圈式纵磁触头大开距真空断路器分闸速度设计

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电工技术学报 2024年第13期39卷 4139-4152页

作者：马飞越姚晓飞刘志远孙尚鹏白涛国网宁夏电力有限公司电力科学研究院银川750002 西安交通大学电气工程学院西安710049 国网宁夏电力有限公司石嘴山供电公司石嘴山750029

合理设计纵磁触头真空断路器的分闸速度特性,可有效避免大电流开断过程中真空电弧阳极斑点的形成或缩短阳极斑点持续时间,显著提升断路器短路电流开断性能。然而,现阶段仍然缺乏线圈式纵磁触头真空断路器全行程分闸速度特性的量化设计... 详细信息

合理设计纵磁触头真空断路器的分闸速度特性,可有效避免大电流开断过程中真空电弧阳极斑点的形成或缩短阳极斑点持续时间,显著提升断路器短路电流开断性能。然而,现阶段仍然缺乏线圈式纵磁触头真空断路器全行程分闸速度特性的量化设计方法。该文试验研究了电弧电流、分闸速度对2/3匝线圈式纵磁触头大电流真空电弧阳极放电模式演变的影响规律,获得了不同分闸速度下线圈式纵磁触头阳极放电模式图,据此提出线圈式纵磁触头分闸速度的量化设计方法:初始分闸速度v1应不小于其从强电弧模式演变为扩散态电弧模式的临界触头开距峰值所对应的分闸速度;平均分闸速度v2应不大于大开距活跃阳极放电模式形成的临界触头开距峰值所对应的分闸速度;同时,对比实际开断过程中触头间隙磁感应强度与阳极放电模式演变的临界纵向磁感应强度,可校验上述分闸速度特性设计的合理性,并能预测该纵磁触头以任一分闸速度开断任一短路电流时的阳极放电模式演变特性。应用上述方法,该文确定了126 kV单断口真空断路器的分闸速度特性设计值为v1=3.5 m/s、v2=3.0 m/s,并通过型式试验验证了断路器在上述分闸速度特性下的短路电流开断性能。

关键词：纵向磁场大开距真空断路器阳极放电模式分闸速度

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Clinical implications of microRNAs in liver cancer stem cells

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Chinese Journal of Cancer 2013年第8期32卷 419-426页

作者： Stella Chai Stephanie ma Department of Clinical Oncology Li Ka Shing Faculty of Medicine The University of Hong Kong State Key Laboratory for Liver Research Li Ka Shing Faculty of Medicine The University of Hong Kong

The prognosis of patients diagnosed with hepatocellular carcinoma (HCC) is often dismal, mainly due to late presentation, high recurrence rate, and frequent resistance to chemotherapy and radiotherapy. Accumulating evidence on the differential microRNA (miRNA) expression patterns between non-tumor and HCC tissues or between liver cancer stem cells (CSCs) and non-CSC subsets and the significant clinical implications of these differences suggest that miRNAs are a promising, non-invasive marker for the prognosis and diagnosis of the disease. This perspective article summarizes the current knowledge of miRNAs in liver CSCs and highlights the need for further investigations of the role of miRNAs in regulating liver CSC subsets for possible future clinical applications.

关键词：肝干细胞 microRNA 临床意义肝癌 miRNAs 肝细胞癌表达模式小RNA

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U-series dating on late Quaternary sediments from Balikun Lake

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Chinese Science Bulletin 1998年第17期43卷 1434-1441页

作者： Jiaqi Liu Zhibang ma Chinese Acad Sci Inst Geol Beijing 100029 Peoples R China

The U-series component-dating method has been employed to date the sediment core B-194 from Balikun Lake. 230Th/ 232Th and 234U/ 232Th ratios in various components of the samples dissolved in different concentration acids were measured respectively. The results indicate that there is a good relationship of the isotopic ratios between the solutions and the residues, and that uranium and thorium isotopic fractionations did not occur during acid leaching. Based on the U-series ages obtained by using component-dating method, a 144-ka time sequence was established corresponding to the upper 25-m interval of the B-194 core, which is in agreement with palaeomagnetic dating results. The fact that the palaeoclimatic and palaeoenvironmental record labeled with U-series ages is correlative with the deep-sea δ 18O SPECmaP also demonstrates that the U-series component-dating method can be used to date lake sediments.

关键词： Balikun Lake sediments component-dating model U-series age.

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Study on match Relationship between Rail and Wheel

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Journal of iron and Steel Research international 2000年第1期7卷 43-47页

作者： ma Teng ZHU Gui-lan Central iron & Steel Research institute

The match relationship between rail and wheel was studied by investigating the behavior of the contact fatigue wear in rail/wheel *** hardnesses of samples were close or equal to that of the real rail and *** the probe of study went further into the condition match and the material match based on the hardness *** experimental results show that the wear rate depends on the hardness ratio(H/H)between rail and wheel,and the safe value of H/Hequals *** fatigue life of materials relies on the operating conditions except *** selected experimental conditions satisfy the condition match except Rheat-treated *** factor H/Sis the main element effecting wears in rail steel and wheel *** nature of the hardness match is the microstructure match under specified operating conditions.

关键词： rail/wheel match wear contact fatigue hardness m icrostructure

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