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High strength mullite-bond SiC porous ceramics fabricated by digital light processing

Journal of Advanced Ceramics 2024年第1期13卷 53-62页

作者： Jian Sun Jingde Zhang Xu Zhang Zihe Li Jianzhang Li Sijie Wei Weibin Zhang weili wang Guifang Han Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) School of Materials Science and EngineeringShandong UniversityJinan 250061China Key Laboratory of Special Functional Aggregated Materials Ministry of EducationShandong UniversityJinan 250100China Materials and Structures Research Centre Department of Mechanical EngineeringUniversity of BathBath BA27AYUK National Engineering Research Centre of Ceramic Matrix Composite Manufacture Technology Xi’an Golden Mountain Ceramic Composites Co.Ltd.Xi’an 710118China School of Physics and Materials Science Changji UniversityChangji 831100China

Fabricating SiC ceramics via the digital light processing(DLP)technology is of great challenge due to strong light absorption and high refractive index of deep-colored SiC powders,which highly differ from those of resin,and thus significantly affect the curing performance of the photosensitive SiC slurry.In this paper,a thin silicon oxide(SiO_(2))layer was in-situ formed on the surface of SiC powders by pre-oxidation treatment.This method was proven to effectively improve the curing ability of SiC slurry.The SiC photosensitive slurry was fabricated with solid content of 55 vol%and viscosity of 7.77 Pa·s(shear rate of 30 s^(−1)).The curing thickness was 50μm with exposure time of only 5 s.Then,a well-designed sintering additive was added to completely convert low-strength SiO_(2) into mullite reinforcement during sintering.Complexshaped mullite-bond SiC ceramics were successfully fabricated.The flexural strength of SiC ceramics sintered at 1550℃in air reached 97.6 MPa with porosity of 39.2 vol%,as high as those prepared by spark plasma sintering(SPS)techniques.

关键词： digital light processing(DLP) SiC ceramics pre-oxidation mullite-bond SiC mechanical properties

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Damage effectiveness assessment method for anti-ship missiles based on double hierarchy linguistic term sets and evidence theory

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Journal of Systems Engineering and Electronics 2022年第2期33卷 393-405页

作者： YAO Tianle wang weili MIAO Run DONG Jun YAN Xuefei Ordnance Engineering College Naval University of EngineeringWuhan 430000China Xi’an Modern Chemistry Research Institute Xi’an 710065 Institute of Systems Engineering Academy of Military ScienceBeijing 100082

The research on the damage effectiveness assessment of anti-ship missiles involves system science and weapon science, and has essential strategic research significance. With comprehensive analysis of the specific process of the damage assessment process of anti-missile against ships, a synthetic damage effectiveness assessment process is proposed based on the double hierarchy linguistic term set and the evidence theory. In order to improve the accuracy of the expert ’s assessment information, double hierarchy linguistic terms are used to describe the assessment opinions of experts. In order to avoid the loss of experts ’ original information caused by information fusion rules, the evidence theory is used to fuse the assessment information of various experts on each case. Good stability of the assessment process can be reflected through sensitivity analysis, and the fluctuation of a certain parameter does not have an excessive influence on the assessment results. The assessment process is accurate enough to be reflected through comparative analysis and it has a good advantage in damage effectiveness assessment.

关键词： anti-ship missile damage effect assessment linguistic term set evidence reasoning

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初创科创平台的国际形象构建与国际科技合作策略——以西方主流媒体对中国大型科创平台的报道为鉴

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中国科技论坛 2024年第6期 167-177页

作者：王威力王海文西安交通大学新闻与新媒体学院陕西西安710049 陕西省国际科学技术合作协会陕西西安710086

通过分析美国《纽约时报》、英国《泰晤士报》、澳大利亚《澳大利亚人报》、加拿大《多伦多星报》等影响力较高的西方主流媒体在过去35年间对北京中关村科技园区、上海张江高科技园区、深圳南山科技园等中国大型科创平台的新闻报道,辅... 详细信息

通过分析美国《纽约时报》、英国《泰晤士报》、澳大利亚《澳大利亚人报》、加拿大《多伦多星报》等影响力较高的西方主流媒体在过去35年间对北京中关村科技园区、上海张江高科技园区、深圳南山科技园等中国大型科创平台的新闻报道,辅以在超过4万个媒体报道及商业数据源中检索有关以陕西秦创原为代表的初创科创平台的报道,借助内容分析法,在媒体报道的基础信息、报道主题、信源类型、科创平台相关描述四方面进行类目构建及编码,运用基于计算机辅助的主题建模,对上述新闻报道进行主题聚类与层次聚类,探究媒体在报道层面存在的相似与差异,探讨形成原因及背后逻辑。研究发现,相关报道呈现出中国科创平台与西方国家公共议程关联度不高、媒体对特定主题存在普遍兴趣但关注点存在差异、共同利益形成与否对西方媒体的报道影响显著等特征。有鉴于此,基于实证研究数据的支撑,以国际合作的认知、语境、共识等层面为出发点,提出对标全球相似知名科创平台强化初创科创平台与全球公共议程关联度、善用“经济框架”将初创科创平台置于全球经济循环话语、构筑基于人类命运共同体价值追求的发展模式,并在形象塑造中设置更加精巧的叙事等策略,从而有助于在当前的媒体与认知环境中构建中国初创科创平台的国际形象,促进国际科技合作。

关键词：科创园区国际传播科技形象国际合作科技合作

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人群聚集场所拥挤踩踏风险评估

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灾害学 2024年第1期39卷 146-151,157页

作者：王维莉薛雪上海海事大学物流研究中心上海201306

为更准确评估人群聚集场所的拥挤踩踏风险,首先基于国内外踩踏事故影响因素的相关研究,从“人、物、环、管”的因素出发,选取拥挤踩踏事故的13个风险因子;然后对2000—2022年全球范围内的200起踩踏事故进行概念编码,统计各风险因素的频... 详细信息

为更准确评估人群聚集场所的拥挤踩踏风险,首先基于国内外踩踏事故影响因素的相关研究,从“人、物、环、管”的因素出发,选取拥挤踩踏事故的13个风险因子;然后对2000—2022年全球范围内的200起踩踏事故进行概念编码,统计各风险因素的频次;最后利用因子分析法的结果,从“风险脆弱性、风险承受力、风险控制力”三个维度表征风险因素,建立人群聚集场所的风险评估指标体系,对风险因素及其风险水平进行量化评价。通过所建立的模型对“韩国梨泰院踩踏事故”风险等级评估发现,该模型可用于计算人群聚集场所的风险水平并划分风险等级。以上海五角场环岛下沉式广场为例,构建若干典型情境,计算该场所拥挤踩踏风险等级,并提出风险管控措施建议。

关键词：拥挤踩踏事故统计风险因子风险评估因子分析

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Formation mechanism of primary phases and eutectic structures within undercooled Pb-Sb-Sn ternary alloys

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Science China(Physics,Mechanics & Astronomy) 2007年第4期50卷 472-490页

作者： wang weili DAI FuPing WEI BingBo Department of Applied Physics Northwestern Polytechnical UniversityXi’an 710072China

The solidification characteristics of three types of Pb-Sb-Sn ternary alloys with different primary phases were studied under substantial undercooling conditions. The experimental results show that primary (Pb) and SbSn phases grow in the dendritic mode, whereas primary (Sb) phase exhibits faceted growth in the form of polygonal blocks and long strips. (Pb) solid solution phase displays strong affinity with SbSn intermetallic compound so that they produce various morphologies of pseudobinary eutectics, but it can only grow in the divorced eutectic mode together with (Sb) phase. Although (Sb) solid solution phase and SbSn intermetallic com- pound may grow cooperatively within ternary eutectic microstructures, they sel- dom form pseudobinary eutectics independently. The (Pb)+(Sb)+SbSn ternary eutectic structure usually shows lamellar morphology, but appears as anomalous eutectic when its volume fraction becomes small. EDS analyses reveal that all of the three primary (Pb), (Sb) and SbSn phases exhibit conspicuous solute trapping effect during rapid solidification, which results in the remarkable extension of sol- ute solubility.

关键词： undercooling dendritic growth eutectic growth ternary eutectic solute trapping

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Identity and Differences Between Chinese and Western Cultural Philosophy

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学术界 2018年第11期 262-272页

作者： Chen Jiafu wang weili College English Teaching and Research Department Tianjin Agricultural University

Cultural philosophy refers to the study of cultural principles with philosophical viewpoints and methods to form a theoretical system of cultural views and cultural activities.It mainly discusses the history and development of culture,the motive force and conditions of culture,the role of tradition in social history,the comparison of various cultures,and the conflict and blending of cultures.This paper attempts to explore an effective way to integrate the two modes of thinking of Chinese and Western cultural philosophy through a comparative analysis of the differences and identity between Chinese and Western cultural philosophy.The study of cultural identity and differences between China and Western countries has a certain practical significance for cross-cultural communication in China.

关键词： cultural philosophy differences identity

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Rapid solidification and dendrite growth of ternary Fe-Sn-Ge and Cu-Pb-Ge monotectic alloys

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Science China(Physics,Mechanics & Astronomy) 2007年第4期50卷 491-499页

作者： ZHANG XueHua RUAN Ying wang weili WEI BingBo Department of Applied Physics Northwestern Polytechnical UniversityXi’an 710072China

The phase separation and dendrite growth characteristics of ternary Fe-43.9%Sn- 10%Ge and Cu-35.5%Pb-5%Ge monotectic alloys were studied systematically by the glass fluxing method under substantial undercooling conditions. The maximum undercoolings obtained in this work are 245 and 257 K, respectively, for these two alloys. All of the solidified samples exhibit serious macrosegregation, indicating that the homogenous alloy melt is separated into two liquid phases prior to rapid solidification. The solidification structures consist of four phases including α-Fe, (Sn), FeSn and FeSn2 in Fe-43.9%Sn-10%Ge ternary alloy, whereas only (Cu) and (Pb) solid solution phases in Cu-35.5%Pb-5%Ge alloy under different undercool- ings. In the process of rapid monotectic solidification, α-Fe and (Cu) phases grow in a dendritic mode, and the transition "dendrite→monotectic cell" happens when alloy undercoolings become sufficiently large. The dendrite growth velocities of α-Fe and (Cu) phases are found to increase with undercooling according to an exponential relation.

关键词： phase separation dendrite growth monotectic alloy undercooling macrosegregation

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Dendrite growth characteristics within liquid Fe-Sb alloy

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Science China(Physics,Mechanics & Astronomy) 2009年第5期52卷 720-728页

作者： wang weili LüYongJun QIN HaiYan WEI BingBo Department of Applied Physics Northwestern Polytechnical UniversityXi’an 710072China

Bulk samples and small droplets of liquid Fe-10%Sb alloys are undercooled up to 429 K (0.24TL) and 568 K (0.32TL), respectively, with glass fluxing and free fall techniques. The high undercooling does not change the phase constitution, and only the αFe solid solution is found in the rapidly solidified alloy. The experimental results show that when the undercooling is below 296 K, the growth velocity of αFe dendrite rises exponentially with the increase of undercooling and reaches a maximum value 1.38 m/s. Subsequently, the growth velocity begins to decrease if undercooling further increases. The αFe phase grows into coarse dendrites under small undercooling conditions, whereas it becomes vermicular dendrites in highly undercooled melts. The solute trapping is closely related to the dendrite growth velocity and cooling rate rather than undercooling. Although the solute trapping can be remarkably suppressed by the rapid dendrite growth, the segregationless solidification is not observed in the present experiments due to the large solidification temperature range.

关键词： liquid physics dendrite growth solute distribution segregationless solidification

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Solute redistribution profiles during rapid solidification of undercooled ternary Co-Cu-Pb alloy

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Science China(Physics,Mechanics & Astronomy) 2014年第3期57卷 393-399页

作者： YAN Na wang weili XIA ZhenChao WEI BingBo Key Laboratory of Applied Physics and Chemistry Ministry of EducationNorthwestern Polytechnical University

The solute redistribution and phase separation of liquid ternary Co-35%Cu-32.5%Pb immiscible alloy have been investigated using glass fluxing method.A bulk undercooling of 125 K was achieved and the macrosegregation pattern was characterized by a top Co-rich zone and a bottom Cu-rich zone.The average solute contents of the two separated zones decreased with the increase of undercooling,except for the solute Pb in Cu-rich zone.With the enhancement of undercooling,a morphological transition from dendrites into equaxied grains occurred to the primary(Co)phase in Co-rich zone.The solute redistribution of Cu in primary(Co)phase was found to depend upon both the undercooling and composition of Co-rich zone.Stokes migration is shown to be the main dynamic mechanism of droplet movement during liquid phase separation.

关键词：溶质再分配铜铅合金过冷度快速凝固三元熔融玻璃宏观偏析分离过程

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Neuroprotective effect of ethyl acetate extract from gastrodia elata against transient focal cerebral ischemia in rats induced by middle cerebral artery occlusion

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Journal of Traditional Chinese Medicine 2015年第6期35卷 671-678页

作者： Duan Xiaohua wang weili Liu Xiaoqing Yan Hanwen Dai Rong Lin Qing the Key Modern Research Laboratory for Ethno-pharmacognosy of Yunnan Higher School Yunnan University of Traditional Chinese Medicine the Department of Pharmacology Yunnan University of Traditional Chinese Medicine Center for Neuron and Disease Frontier Institute of Science and TechnologyXi'an Jiaotong University

OBJECTIVE: To investigate the protective effect of neuroprotection against transient focal cerebral ischemia of the extract from Tianma(Rhizoma Gastrodiae) and the possible mechanisms underlying the action.METHODS: Cerebral ischemia-reperfusion injury was induced through middle cerebral artery occlusion(MCAO). Adult male Sprague-Dawley rats were randomly divided into four groups: sham-operated,ischemia-reperfusion model, 102.6 mg/kg extract treated and 11.4 mg/kg extract treated groups. The extract was prepared from gastrodia elata with ethyl acetate. The effect of the extract tested on rat neurological de fi cits and Cerebral index, cerebral infarct volume, brain injury, terminal dexynucleotidyl transferase-mediated d UTP nick end labeling(TUNEL) and B-cell lymphoma-2(Bcl-2) positive cells.RESULTS: The extract was able to reduce neurological scores, cerebral index and cerebral infarction rate. The brain injury was also relieved by the extract. The results of immunofluorescence staining analysis indicated that the extract increased the expression of Bcl-2 and reduced TUNEL-positive cells significantly in the extract treated groups.CONCLUSION: These results suggested that the extract relieved ischemic injury induced by transient focal cerebral ischemia in rats, and this neuroprotective effect might be partially due to the attenuated apoptosis pathway.

关键词： Ethyl acetate Gastrodia Neuroprotec-tive agents Reperfusion injury Apoptosis

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