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OSL chronology reveals Late Pleistocene floods and their impact on landform evolution in the lower reaches of the Keriya River in the Taklima.an Desert

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Journal of Geographical Sciences 2023年第5期33卷 945-960页

作者： ZHANG Feng WANG Jiao ma.Li Dilibaier TUERSUN College of Geography and Remote Sensing Sciences Xinjiang Key Laboratory of Oasis EcologyXinjiang UniversityUrumqi830046China

The impacts of clima.e change on the relationship between fluvial processes and dune landform evolution have been studied.However,the chronology data used to examine this relationship are deficient.The Keriya River has a glacial origin in the Kunlun Mountains on the south ma.gin of the Tarim Basin.The river flows into the Taklima.an Desert,the second largest shifting-dune desert in the world.The dry channels and shifting dunes in this area provide an ideal opportunity to investigate fluvial and aeolian landform evolution processes and their relationship with clima.e change.We investigated this area during 2008-2011 and obtained 18 fluvial sediment samples from 16 sections for optically stimulated luminescence(OSL)dating.The results show that the ages ranged from 3.4-44.1 ka.Most of the samples(13)were Holocene in age,around 11 ka,8-9 ka,5-6.5 ka,4.6 ka.a.d 3.4-3.7 ka.a.d were distributed along ancient river channels around sites of Yuansha and ka.a.un.Two samples close to the Hotan River(38-47 ka)fall within the ma.ine Isotope Stage 3(MIS3).Three samples(from one section)were located near ancient channels flowing towards the Yuansha Site and had ages of around 14.5 ka,i.e.,during the Last Glacial ma.imum(LGM).The analyses of the sediment samples and OSL ages suggest that the Keriya River flooded in the Holocene,the LGM,and MIS3.Fluvial sediments provided the source ma.erial for the dunes,and fluvial processes affected the landform evolution in the lower Keriya River.Our results suggest that most of the dunes covered in fluvial sediments in the lower reaches and the area west of the Keriya River developed since the Holocene.This differs from the results of previous studies,which suggested that they developed since the Han(202BC-220AD)and Tang(618-907AD)dynasties.The OSL ages of the fluvial sediments are consistent with the reported deglaciation(after glacial advance)ages in the alpine mountains surrounding the Tarim Basin.This suggests that clima.e fluctuations ma. have affected the occurrence of floods and the fo

关键词： Taklima.an Desert flood inundation dunes MIS3 LGM Holocene deglaciation

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近地表水汽密度对多年冻土区地表辐射的影响研究——以北麓河地区为例

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气候变化研究进展 2024年第3期20卷 304-315页

作者：马安静张明礼周志雄王永斌王成福兰州理工大学土木工程学院兰州730050 中国科学院西北生态环境与资源研究院冻土工程国家重点实验室兰州730000

气候暖湿化背景下,青藏高原地区大气水汽含量的增大通过影响地表辐射进而影响多年冻土地表能量分配及其热稳定性。以青藏高原中部北麓河地区的气象数据与活动层水热数据为基础,分析了2 m处空气相对湿度和夏季典型降雨事件对地表反照率... 详细信息

气候暖湿化背景下,青藏高原地区大气水汽含量的增大通过影响地表辐射进而影响多年冻土地表能量分配及其热稳定性。以青藏高原中部北麓河地区的气象数据与活动层水热数据为基础,分析了2 m处空气相对湿度和夏季典型降雨事件对地表反照率及辐射四分量的影响。结果表明:大气水汽通过削弱太阳短波辐射,吸收地面长波辐射,增加向下长波辐射,进而降低地表反照率。大气水汽对地表辐射的影响具有明显的季节性特征,夏季大气水汽对太阳短波辐射的削弱作用最明显,并且发射的向下长波辐射较多;冬季大气水汽对太阳短波辐射的削弱作用相对较弱,发射向下长波辐射较少。在研究时段内北麓河地区夏季和冬季空气相对湿度每增加10%,太阳短波辐射日均值分别减少54.9和9.8 W/m2,向下长波辐射日均值分别增加14.8和3.9 W/m2。秋季空气中水汽含量的变化对地表反照率的影响最大,秋季空气相对湿度每减小10%,地表反照率增加0.15;春季最小,春季空气相对湿度每增加10%,地表反照率仅降低0.01。夏季不同典型降雨事件导致近地表水汽密度和浅层土壤含水量增大,使地表反照率降低。夏季不同类型降雨事件对地表反照率的影响程度表现为:大雨>中雨>小雨。研究结果为暖湿化气候背景下青藏高原中部多年冻土区地表能量平衡分析提供参考。

关键词：多年冻土青藏高原空气湿度反照率辐射

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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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Fe_(25)Co_(25)Pt_(25)B_(25)高熵纳米复相永磁体的组织结构与磁性能

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材料热处理学报 2024年第3期45卷 22-28页

作者：贾雨桐薛钧升李艳辉马殿国张伟大连理工大学材料科学与工程学院三束材料改性教育部重点实验室辽宁大连116024

采用液态急冷法制备了高熵Fe_(25)Co_(25)Pt_(25)B_(25)合金,研究了其热处理前后的组织结构及磁性能。结果表明:Fe_(25)Co_(25)Pt_(25)B_(25)高熵合金具有较高的非晶形成能力,液态急冷合金形成了非晶态结构,表现出软磁特性。Fe_(25)Co_(... 详细信息

采用液态急冷法制备了高熵Fe_(25)Co_(25)Pt_(25)B_(25)合金,研究了其热处理前后的组织结构及磁性能。结果表明:Fe_(25)Co_(25)Pt_(25)B_(25)高熵合金具有较高的非晶形成能力,液态急冷合金形成了非晶态结构,表现出软磁特性。Fe_(25)Co_(25)Pt_(25)B_(25)高熵非晶合金热处理结晶化过程为:非晶相→非晶相+fcc-(Fe,Co)Pt相→非晶相+fcc-(Fe,Co)Pt+L1_(0)-(Fe,Co)Pt+(Fe,Co)2B相→非晶相+L1_(0)-(Fe,Co)Pt+(Fe,Co)2B相→L1_(0)-(Fe,Co)Pt+(Fe,Co)2B相。经843 K热处理900 s后,Fe_(25)Co_(25)Pt_(25)B_(25)合金形成了由有序面心四方结构的永磁L1_(0)-(Fe,Co)Pt相和软磁(Fe,Co)2B相组成的纳米复相组织,平均晶粒尺寸约为19 nm,表现出纳米复相永磁体特性,其矫顽力(iHc)、剩磁(Br)、剩磁比(Mr/Ms)和磁能积((BH)_(ma.))分别为946.8 ka·m^(-1)、0.46 T、0.78和40.9 kJ·m^(-3)。其超大iHc主要是高熵化使L10相的c/a增大导致磁晶各向异性增大的结果。

关键词： FeCoPtB高熵合金纳米复相永磁体非晶态合金结晶化矫顽力

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Pandemic of the aging society—sporadic cerebral sma.l vessel disease

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Chinese Medical Journal 2021年第2期134卷 143-150页

作者： Alexander Yuk Lun Lau Bonaventure Yiu Ming Ip Ho Ko Bonnie Yin ka Lam Lin Shi karen ka Yan ma.Lisa Wing Chi Au Yannie Oi Yan Soo Thoma. Wai Hong Leung Adrian Wong Vincent Chung Tong Mok Division of Neurology Department of Medicine and TherapeuticsThe Faculty of MedicineThe Chinese University of Hong KongHong KongChina Gerald Choa Neuroscience Centre Faculty of MedicineLui Che Woo Institute of Innovative MedicineThe Chinese University of Hong KongHong KongChina Faculty of Medicine School of Biomedical SciencesLi Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong KongChina ma.garet Cheung K.L.Cheung Research Centre for ma.agement of Parkinsonism Faculty of MedicineThe Chinese University of Hong KongHong KongChina Department of Ima.ing and Interventional Radiology The Chinese University of Hong KongHong KongChina Shenzhen Research Institute The Chinese University of Hong KongShenzhenGuangdongChina.

Age-related sporadic cerebral sma.l vessel disease(CSVD)has gained increasing attention over the past decades because of its increasing prevalence associated with an aging population.The widespread application of and advances in brain ma.netic resonance ima.ing in recent decades have significantly increased researchers’understanding in the in vivo evolution of CSVD,its impact upon the brain,its risk factors,and the mechanisms that explain the various clinical ma.ifestation associated with sporadic CSVD.In this review,we aimed to provide an update on the pathophysiology,risk factors,bioma.kers,and the determinants and spectrum of the clinical ma.ifestation of sporadic CSVD.

关键词： Cerebral sma.l vessel disease Clinical spectrum Pathophysiology

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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 ma. 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 ma.ntaining 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 forma.ion 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 tonoplast.Electron microscopy revealed that the expression of these replication proteins alone is sufficient to induce spherule forma.ion 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 norma. 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 Fema.e but not in ma.e 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 ma.e, castrated, fema.e 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 fema.e and ovariectomized hamsters. In contrast, three levels of dietary calcium had no effect on lipoprotein profiles in both intact ma.e 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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Donor ductal anoma.y is not a contraindication to right liver lobe donation

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Hepatobiliary & Pancreatic Diseases International 2019年第4期18卷 343-347页

作者： Kenneth SH Chok James YY Fung Wing Chiu Dai Sui Ling Sin ka Wing ma.Albert CY Chan Tan To Cheung Chung ma. Lo Department of Surgery The University of Hong Kong102 Pok Fu Lam RoadHong KongChina State Key Laboratory for Liver Research The University of Hong Kong102 Pok Fu Lam RoadHong KongChina Department of Medicine The University of Hong Kong102 Pok Fu Lam RoadHong KongChina

Background:Data of living-donor liver transplantation(LDLT)suggested that donor ductal anoma.y ma. contribute to postoperative biliary complications in recipients and in donors.This retrospective study aimed to determine if the occurrence of postoperative biliary stricture in donors or recipients in rightlobe LDLT(RLDLT)is related to donor biliary anatomy type.Methods:We analyzed our RLDLT recipients’clinical data and those of their graft donors.The recipients were divided into 2 groups:with and without postoperative biliary stricture.The 2 groups were compared.The prima.y endpoints were donor biliary anatomy type and postoperative biliary complication incidence;the secondary endpoints were 1-,3-and 5-year graft and patient survival rates.Results:Totally 127 patients were included in the study;25(19.7%)of them developed biliary anastomotic stricture.In these 25 patients,16 had type A biliary anatomy,3 had type B,2 had type C,3 had type D,and 1 had type E.In the 127 donors,96(75.6%)had type A biliary anatomy,13(10.2%)had type B,6(4.7%)had type C,10(7.9%)had type D,and 2(1.6%)had type E.Biliary stricture was seen in 2 donors,who had type A biliary anatomy.None of the recipients or donors developed bile leakage.No association between the occurrence of postoperative biliary stricture and donor biliary anatomy type was found(P=0.527).Conclusions:The incidence of biliary stricture in donors or recipients after RLDLT was not related to donor biliary anatomy type.As postoperative complications were similar in whatever type of donor bile duct anatomy,donor ductal anoma.y should not be considered a contraindication to donation of right liver lobe.

关键词： Living donor liver transplantation Right liver donation Biliary complications Cholangiograms Ductal anoma.y

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DH590冷轧板及镀锌板电阻点焊工艺窗口及点焊一致性的研究

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热加工工艺 2024年第3期53卷 82-87页

作者：卢岳牛月鹏潘进马成孙力王连轩张龙柱河钢集团钢研总院河北石家庄050023 河钢集团邯钢公司河北邯郸056015

采用电阻点焊对DH590冷轧板及其镀锌板进行工艺窗口和焊点一致性试验,对焊点进行了拉剪试验和十字拉伸试验,分析了点焊接头的显微组织、硬度分布以及断口形貌。结果表明:相比于冷轧板,DH590镀锌板焊接工艺窗口向右移动(增大)约2 ka,同... 详细信息

采用电阻点焊对DH590冷轧板及其镀锌板进行工艺窗口和焊点一致性试验,对焊点进行了拉剪试验和十字拉伸试验,分析了点焊接头的显微组织、硬度分布以及断口形貌。结果表明:相比于冷轧板,DH590镀锌板焊接工艺窗口向右移动(增大)约2 ka,同时工艺窗口范围变窄,熔核形成更加充分,发生飞溅时的熔核直径更大。两种点焊接头熔核区组织为板条马氏体,但镀锌板熔核区的平均硬度更高。点焊一致性试验中,熔核直径均达到标准要求,未见明显波动。工艺窗口内的焊点失效模式以拔出断裂为主,从断口观察到大量的剪切韧窝,呈现出塑性断裂的特点。

关键词：镀锌板电阻点焊拉剪力工艺窗口点焊一致性

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高电压等级真空断路器研究现状及展望

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高电压技术 2024年第2期50卷 451-466页

作者：钟建英孙广雷杨葆鑫赵晓民李旭旭马朝阳贾航张旭升中国电气装备集团科学技术研究院有限公司上海200040 平高集团有限公司平顶山467001 河南省高压电器研究所有限公司平顶山467001 沈阳工业大学电气工程学院沈阳110027

针对绿色电网发展需求,总结对比了现阶段SF6完全替代技术和部分替代技术路线的特点及相关技术,指出真空开断技术是电网绿色低碳发展的有效手段。对比分析现阶段多断口真空断路器的技术特点及研究现状,认为单断口真空断路器在结构及可靠... 详细信息

针对绿色电网发展需求,总结对比了现阶段SF6完全替代技术和部分替代技术路线的特点及相关技术,指出真空开断技术是电网绿色低碳发展的有效手段。对比分析现阶段多断口真空断路器的技术特点及研究现状,认为单断口真空断路器在结构及可靠性方面具有显著优势。目前商业化单断口真空灭弧室已经发展到145 kV/40 ka,综述了高电压大电流单断口真空灭弧室内外绝缘技术、电弧形态演变规律及分合闸控制、温升特性和真空灭弧室焊接质量稳定性的研究现状及未来发展趋势。结果表明:真空灭弧室内部真空间隙的均压设计及长真空间隙绝缘“饱和”问题是制约灭弧室电压等提升的关键因素;耐烧蚀触头材料的制备及磁场设计对触头表面阳极斑点的形成过程和真空断路器分合闸速度匹配至关重要;选取低回路电阻的触头结构、优化真空断路器散热结构能够有效提升真空灭弧室额定通流能力;此外,总结了真空灭弧室焊接质量和稳定性的影响因素,指出陶瓷金属化并选取合适的钎焊温度和焊料能够显著提升焊接强度;最后指出真空断路器趋向于大容量、小型化、智能化、低过电压、免维护、专用化和多功能化发展。

关键词： SF6替代技术真空开断技术单断口真空灭弧室大容量可靠性

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