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Analysis of local crystallographic orientation in an annealed Ti60 billet

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journal of Materials Science & Technology 2019年第4期35卷 591-595页

作者： z.B.zhao z.Liu Q.j.Wang j.R.Liu R.yang Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

A heterogeneous microstructure in terms of local orientation distribution is often found in near-α titanium alloys. The presence of large regions with similar crystallographic orientation, called ‘macrozones',could drastically decrease the fatigue performance of titanium alloys. The present work reports on the crystallographic orientation of a near-α titanium alloy, Ti60, billet after annealing in an α+β phase *** texture was found to be weak, and no obvious macrozone was found in our measured zone where the variant selection is suppressed. Meanwhile, in-depth electron backscattered diffraction(EBSD) analysis was applied to evaluate the final microstructure, and the mechanisms by which they formed were analyzed.

关键词： Titanium alloys Microstructure Texture Heat treatment EBSD

Analysis of the inflection points of height-diameter models

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Forest Ecosystems 2024年第4期11卷 414-422页

作者： Tzeng Yih Lam Mark j.Ducey Department of Forest Resources Management Faculty of ForestryThe University of British Columbia2045-2424 Main MallVancouverBCV6T 1Z4 Canada Department of Natural Resources and the Environment University of New Hampshire114 James HallDurhamNH 03824USA

The inflection point is an important feature of sigmoidal height-diameter(H-D)*** is often cited as one of the properties favoring sigmoidal model ***,there are very few studies analyzing the inflection points of H-D *** goals of this study were to theoretically and empirically examine the behaviors of inflection points of six common H-D models with a regional *** six models were the Wykoff(WYK),Schumacher(SCH),Curtis(CUR),HossfeldⅣ(HOS),von Bertalanffy-Richards(VBR),and Gompertz(GPz)*** models were first fitted in their base forms with tree species as random effects and were then expanded to include functional traits and spatial *** distributions of the estimated inflection points were similar between the two-parameter models WYK,SCH,and CUR,but were different between the threeparameter models HOS,VBR,and *** produced some of the largest inflection *** and VBR produced concave H-D curves without inflection points for 12.7%and 39.7%of the tree *** species or decreasing shade tolerance resulted in larger inflection *** trends in the estimated inflection points of HOS and VBR were entirely opposite across the ***,HOS could produce concave H-D curves for portions of the *** on the studied behaviors,the choice between two-parameter models may not *** recommend comparing seve ral three-parameter model forms for consistency in estimated inflection points before deciding on *** sigmoidal models to have inflection points does not necessarily mean that they will produce fitted curves with *** study highlights the need to integrate analysis of inflection points into modeling H-D relationships.

关键词： Concavity Forest inventory and analysis Generalized height-diameter models Growth functions Height-diameter functions Mixed-effects modeling Points of inflection Species-specific models

Deformation behaviors of Cu bicrystals with an inclined twin boundary at multiple scales

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journal of Materials Science & Technology 2017年第7期33卷 698-702页

作者： L.L.Li z.j.zhang P.zhang j.Tan j.B.yang z.F.zhang Shenyaag National Laboratory for Materials Science lastitute of Metal Research Chinese Academy of Sciences Shenyaag 110016 China

Cu bicrystals of different sizes with a sole twin boundary（TB） inclined at 45？with respect to the loading direction were deformed under unidirectional and cyclic loading, respectively. It is found that the slip bands（SBs） parallel to the TB can be activated near the TB at all scales without obeying the Schmid＇s *** is concerned with the local stress enhancement in the macroscale while it is more closely related to the scarce dislocation sources in the microscale. Moreover, a wedge-shaped zone formed near the TB in the microscale ascribed to the limited specimen size.

关键词： Bicrystal Micropillar Twin boundary Schmid factors Size effect

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全球变暖与城市

气候变化研究进展 2024年第4期20卷 504-508页

作者：赵宗慈罗勇黄建斌清华大学地球系统科学系北京100084 中国气象局国家气候中心北京100081 中国科学院大学资源环境学院北京100049

城市(city)、城镇(town)和都市(urban)都是城市的考虑范围。城市的界定是一个复杂的问题,直到目前为止,没有一个确定城市边界的国际标准。一般以大量人居住与生活和工作的地方,政府、商业与运输的枢纽为城市,考虑“城市本身”“城市聚... 详细信息

城市(city)、城镇(town)和都市(urban)都是城市的考虑范围。城市的界定是一个复杂的问题,直到目前为止,没有一个确定城市边界的国际标准。一般以大量人居住与生活和工作的地方,政府、商业与运输的枢纽为城市,考虑“城市本身”“城市聚集”“大城市区”等作为界定。世界上超过一半人口生活在城市,处在气候变化的前沿。据联合国统计,2022年城市人口占54.5%,预计到2030年将可能达到60%,2050年将可能达到68%。城市的分级也很复杂,一般城市分级从万人极小城市,到千万人特大城市,城镇人口则可能小到仅有百十人。据联合国统计,人口至少101万的城市,在2022年全球有512个,预计2030年全球将达到662个。观测到的不利影响特别集中在经济和社会边缘化(低收入或无收入)的城市居民中(高信度)。人口1000万或以上的特大城市群(megacity)是人为造成的,更值得注意[1-2]。

关键词：社会边缘化城镇人口城市边界城市聚集特大城市全球变暖城市居民气候变化

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Photoluminescence from Silicon Nanocrystals in Encapsulating Materials

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journal of Materials Science & Technology 2013年第3期29卷 221-224页

作者： z.Deng X.D.Pi j.j.zhao D.yang State Key Laboratory of Silicon Materials and Department of Materials Science and Engineering Zhejiang University

Naturally oxidized freestanding silicon nanocrystals （Si NCs） are incorporated in commonly used encapsulating materials to explore the photoluminescent application of Si NCs in device structures such as solid-state lighting light-emitting diodes （LEDs） and solar cells. The quantum yield of Si NCs before the incorporation has reached about 45% at the excitation wavelength of 370 nm without any special surface modification. It is found that medium Ioadings, e.g., 5 wt% of Si NCs in encapsulating materials help to obtain high external quantum efficiency （EQE） of the mixtures of Si NCs and encapsulating materials. The curing of encapsulating materials significantly reduces EQE. Among all the encapsulating materials investigated in this work, silicone- OE6551 enables the highest EQE （21% at excitation wavelength λex = 370 nm） after curing. Based on current findings, we have discussed the continuous efforts to advance the photoluminescent application of Si NCs.

关键词： Photoluminescence Silicon nanocrystals Epoxy Silicone Quantum yield External quantum efficiency

MECHANICAL PROPERTIES OF LONGITUDINAL SUBMERGED ARC WELDED STEEL PIPES USED FOR GAS PIPELINE OF OFFSHORE OIL

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Acta Metallurgica Sinica(English Letters) 2008年第2期21卷 85-93页

作者： z.z. yang W. Tian Q.R. Ma Y.L. Li j.K. Li j.z. Gao H.B. zhang Y.H. yang Tubular Goods Research Center of CNPC Xi＇an 710065 China Xiran Aerotechnical College Xi＇an 710077 China

Since the development of offshore oil and gas, increased submarine oil and gas pipelines were installed. All the early steel pipes of submarine pipelines depended on importing because of the strict requirements of comprehensive properties, such as, anti-corrosion, resistance to pressure and so on. To research and develop domes- tic steel pipes used for the submarine pipeline, the Longitudinal-seam Submerged Arc Welded （LSAW） pipes were made of steel plates cut from leveled hot rolled coils by both the jCOE and UOE （the forming process in which the plate like the letter “j”, “C”, “0” or “U” shape, then expansion） forming processes. Furthermore, the mechanical properties of the pipe base metal and weld metal were tested, and the results were in accordance with the corresponding pipe specification API SPEC 5L or DNV- OS-FI01, which showed that domestic LSAW pipes could be used for submarine oil and gas pipelines.

关键词： Mechanical properties Offshore oil and gas Longitudinal-seamsubmerged arc welded pipe (LSA W) Pipeline jCOE formingprocess UOE forming process

Step‑by‑Step Modulation of Crystalline Features and Exciton Kinetics for 19.2%Efficiency Ortho‑Xylene Processed Organic Solar Cells

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Nano-Micro Letters 2024年第2期16卷 258-272页

作者： Bosen zou Weiwei Wu Top Archie Dela Pena Ruijie Ma Yongmin Luo Yulong Hai Xiyun Xie Mingjie Li zhenghui Luo jiaying Wu Chuluo yang Gang Li He Yan Department of Chemistry Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction The Hong Kong University of Science and TechnologyClear Water BayHong KongPeople’s Republic of China Department of Electronic and Information Engineering Research Institute for Smart Energy(RISE)Guangdong‑Hong Kong‑Macao(GHM)Joint Laboratory for Photonic‑Thermal‑Electrical Energy Materials and DevicesThe Hong Kong Polytechnic UniversityHung HomKowloonHong Kong 999077People’s Republic of China The Hong Kong University of Science and Technology Function HubAdvanced Materials ThrustNanshaGuangzhou 511400People’s Republic of China Department of Applied Physics The Hong Kong Polytechnic UniversityHong KongPeople’s Republic of China Shenzhen Key Laboratory of New Information Display and Storage Materials College of Materials Science and EngineeringShenzhen UniversityShenzhen 518060People’s Republic of China

With plenty of popular and effective ternary organic solar cells(OSCs)construction strategies proposed and applied,its power conversion efficiencies(PCEs)have come to a new level of over 19%in single-junction ***,previous studies are heavily based in chloroform(CF)leaving behind substantial knowledge deficiencies in understanding the influence of solvent choice when introducing a third ***,we present a case where a newly designed asymmetric small molecular acceptor using fluoro-methoxylated end-group modification strategy,named BTP-BO-3FO with enlarged bandgap,brings different morphological evolution and performance improvement effect on host system PM6:BTP-eC9,processed by CF and ortho-xylene(o-XY).With detailed analyses supported by a series of experiments,the best PCE of 19.24%for green solvent-processed OSCs is found to be a fruit of finely tuned crystalline ordering and general aggregation motif,which furthermore nourishes a favorable charge generation and recombination ***,over 19%PCE can be achieved by replacing spin-coating with blade coating for active layer *** work focuses on understanding the commonly met yet frequently ignored issues when building ternary blends to demonstrate cutting-edge device performance,hence,will be instructive to other ternary OSC works in the future.

关键词： Organic solar cells Ternary design Solvent selection Flouro-methoxylated end group Morphological ordering

识别液态和固态水的四波段水指数及其在咸海流域的应用

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中国科学：地球科学 2024年第3期54卷 788-807页

作者：岳兵陈曦李赛博杜正平 john WILSON 杨筠慧焦毅蒙黄双燕周成虎中国科学院新疆生态与地理研究所乌鲁木齐830011 中国科学院大学资源与环境学院北京100049 中国科学院地理科学与资源研究所北京100101 Spatial Sciences Institute University of Southern CaliforniaLos AngelesCA 90089-0374USA

虽然已有许多水指数被运用于咸海和咸海流域的水域面积分析,然而已有研究尚存在很大的不确定性.由于所使用水指数存在水体误识别的问题,导致不同研究得出的结论差异很大.此外,各种研究采用的咸海流域面积也差异很大,流域面积从约1百万km... 详细信息

虽然已有许多水指数被运用于咸海和咸海流域的水域面积分析,然而已有研究尚存在很大的不确定性.由于所使用水指数存在水体误识别的问题,导致不同研究得出的结论差异很大.此外,各种研究采用的咸海流域面积也差异很大,流域面积从约1百万km^(2)到2百万km^(2)不等.因此,我们首先界定咸海流域、锡尔河和阿姆河流域以及它们的上、中、下游的边界,然后提出可识别液态水和固态水的四波段指数(ILSW),以解决传统水指数的误别偏差问题.ILSW基于绿色、红色、近红外和热红外波段反射值,是归一化差异水指数(NDWI)和地表温度(LST)的合成.验证结果显示,ILSW水指数在咸海流域的准确性远远超过其他指数.研究结果表明,南咸海的水域面积平均每年缩小963km^(2),而北咸海几乎没有变化;由于气候变暖,咸海流域上游常年冰雪面积有大幅度退缩趋势,阿姆河上游和锡尔河上游常年冰雪的退缩速率分别为年均6233和384km^(2)/a.气候变化和人类活动引起了严重的水亏问题.自20世纪90年代以来,水亏呈增长趋势,平均每年增长3.778亿m^(3).2011~2020年期间,整个咸海流域平均总水亏量为76.967亿m^(3),而锡尔河流域上游(咸海流域的一个组成部分)水盈余量为25.461亿m^(3).研究结果对制定咸海流域可持续发展战略具有重要意义.

关键词：咸海流域锡尔河流域阿姆河流域水指数水面积覆盖水亏缺气候变化

Gyroscopic modes decoupling method in parametric instability analysis of gyroscopic systems

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Acta Mechanica Sinica 2018年第5期34卷 963-969页

作者： Y.j.Qian X.D.yang H.Wu W.zhang T.z.yang College of Mechanical Engineering Beijing University of TechnologyBeijing 100124China Department of Mechanics Tianjing UniversityTianjing 300072China

Traditional procedures to treat vibrations of gyroscopic continua involve direct application of perturbation methods to a system with both a strong gyroscopic term and other weakly coupled *** this study,a gyroscopic modes decoupling method is used to obtain an equivalent system with decoupled gyroscopic modes having only weak *** the axially moving string as an example,the instability boundaries in the vicinity of parametric resonances are detected using both the traditional coupled gyroscopic system and our system with decoupled gyroscopic modes,and the results are compared to show the advantages and disadvantages of each method.

关键词： Axially moving material Decoupling of gyroscopic modes Parametric instability Perturbation method Gyroscopic system