检索结果-内蒙古大学图书馆

地球物理学进展 2024年第1期39卷 63-76页

作者：敬嘉良陈国雄程飞丹阳刘江平徐富文王德涛地质过程与矿产资源国家重点实验室中国地质大学(武汉)武汉430074 中国地质大学(武汉)资源学院武汉430074 中国地质大学(武汉)海洋学院武汉430074 中国地质大学(武汉)地球物理与空间信息学院武汉430074 湖北省地质局第一地质大队大冶435000

背景噪声地震成像方法已被广泛应用于探测壳幔深部结构;近些年来,该方法在浅地表结构成像中的应用研究也在蓬勃发展,然而近地表场源不均匀等因素导致高频面波信号往往难以准确恢复,以牺牲时间来提高信噪比的观测方式会极大限制其在工程... 详细信息

背景噪声地震成像方法已被广泛应用于探测壳幔深部结构;近些年来,该方法在浅地表结构成像中的应用研究也在蓬勃发展,然而近地表场源不均匀等因素导致高频面波信号往往难以准确恢复,以牺牲时间来提高信噪比的观测方式会极大限制其在工程勘查中的应用.本文尝试讨论超短时背景噪声成像技术在浅层地质结构探测中的应用效果.笔者利用湖北应城地区超短时(1 h)线性台阵地震背景噪声记录,使用被动源面波多道分析法从虚拟炮集中提取相速度频散曲线,通过反演获取了浅地表二维横波速度结构.结果表明,利用本文方案可以恢复高信噪比面波信号、获取高信噪比的频散能量以及拾取高精度相速度;反演速度结构与实际测井数据吻合度好,成像结果有效揭示了测区150 m以浅的地层结构,证明了超短时背景噪声成像技术在浅层地质结构调查中具有很大的应用潜力.

关键词：背景噪声超短时频散曲线浅层地质结构横波速度反演

来源：评论

学校读者我要写书评

暂无评论

Rapid Formation of Full Intermetallic Bondlines for Die Attachment in High-Temperature Power Devices Based on Micro-sized Sn-Coated Ag Particles

引用

JOM 2019年第9期71卷 3049-3056页

作者： Yu, fuwen Liu, Hao Hang, Chunjin chen, Hongtao Li, Mingyu Harbin Inst Technol Shenzhen Dept Mat Sci & Engn Shenzhen 518055 Peoples R China Beijing Santel Technol & Trading Corp Beijing 100039 Peoples R China Harbin Inst Technol State Key Lab Adv Welding & Joining Harbin 150001 Heilongjiang Peoples R China

A new die attach material prepared by pressing micro-sized Sn-coated Ag powders as a preform is proposed for high-temperature power device packaging. The Sn-coated Ag powders were completely transformed into Ag3Sn with a melting point of 480 degrees C after bonding at 250 degrees C for 10 min, subsequently producing a bondline which can sustain a much higher temperature than the processing temperature. The detailed microstructural analysis indicates that a fine-grained full Ag3Sn bondline with high-density twin boundaries can be formed in a short reflow time, which contributes to the improved performance of the full Ag3Sn bondline, with an average shear strength of 37.5 MPa at 400 degrees C. Nano-indentation testing showed that the average hardness and elasticity modulus of the prepared full Ag3Sn bondline were 3.1 +/- 0.26 GPa and 84.56 +/- 6.13 GPa, respectively. The electrical resistivity was measured to be 11.42 mu omega cm. The shear strength at 400 degrees C was kept above 20 MPa after aging at 200 degrees C for 200 h due to the thermostability of Ag3Sn microstructure in the bondlines.

关键词： Tin alloys

来源：评论

学校读者我要写书评

暂无评论

Design, Preparation, and Bioactivity Study of New Fusion Protein HB-NC4 in the Treatment of Osteoarthritis

引用

FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY 2021年 9卷 700064页

作者： Wang, Yaya Li, Lian Wei, Qiang Chai, Rongrong Yao, Qingqiang Liang, chen Wang, fuwen Li, Yan Shandong First Med Univ & Shandong Acad Med Sci Inst Mat Med Jinan Peoples R China Shandong Univ Cheeloo Coll Med Sch Pharmaceut Sci Key Lab Chem BiolMinist Educ Jinan Peoples R China Tangshan Normal Univ Dept Phys Educ Tangshan Peoples R China Shandong Med Coll Jinan Peoples R China

Osteoarthritis (OA) is now becoming the main disease that affects public health. There is no specific medicine used for OA in clinical application until now. Recently, several studies demonstrated that OA is closely related to the complement system, and some complement regulators such as N-terminal non-collagenous domain 4 (NC4) aimed at alleviating OA have shown a promising therapeutic effect. However, targeting ability is the main limitation for NC4. In this study, a fusion protein named heparin-binding domain-N-terminal non-collagenous domain 4 (HB-NC4) was proposed to solve this problem, which could provide a better way for OA treatment. First, HB-NC4 plasmid was constructed using ClonExpress II one-step ligation kit method. And Escherichia coli BL21 was utilized to express the fusion protein, Ni2+-sepharose, and a desalting gravity column were introduced to purify HB-NC4. The results showed that 0.84 mg HB-NC4 could be obtained from a 1 L culture medium with a purity higher than 92.6%. Then, the hemolytic assay was introduced to validate the anti-complement activity of HB-NC4;these results demonstrated that both HB-NC4 and NC4 had a similar anti-complement activity, which indicated that heparin-binding (HB) did not affect the NC4 structure. Targeting ability was investigated in vivo. HB-NC4 showed a higher affinity to cartilage tissue than NC4, which could prolong the retention time in cartilage. Finally, the destabilization of the medial meniscus (DMM) model was applied to investigate HB-NC4 pharmacodynamics in vivo. The results indicated that HB-NC4 significantly slowed cartilage degradation during the OA process. In summary, compared with NC4, HB-NC4 had better-targeting ability which could improve its therapeutic effect and prolonged its action time. It could be used as a new complement regulator for the treatment of OA in the future.

关键词： osteoarthritis C5b-9 HB NC4 fusion protein

来源：评论

学校读者我要写书评

暂无评论

Spatial patterns and conservation of genetic and phylogenetic diversity of wildlife in China

引用

SCIENCE ADVANCES 2021年第4期7卷 000-000页

作者： Hu, Yibo Fan, Huizhong chen, Youhua Chang, Jiang Zhan, Xiangjiang Wu, Hua Zhang, Baowei Wang, Meng Zhang, Wenyan Yang, Lin Hou, Xian Shen, Xing Pan, Tao Wu, Wei Li, Jun Hu, Haihua Wei, fuwen Chinese Acad Sci Inst Zool CAS Key Lab Anim Ecol & Conservat Biol Beijing Peoples R China Univ Chinese Acad Sci Beijing Peoples R China Chinese Acad Sci Ctr Excellence Anim Evolut & Genet Kunming Yunnan Peoples R China Chinese Acad Sci Chengdu Inst Biol Chengdu Peoples R China Chinese Res Inst Environm Sci State Key Lab Environm Criteria & Risk Assessment Beijing Peoples R China Cent China Normal Univ Sch Life Sci Inst Evolut & Ecol Wuhan Peoples R China Anhui Univ Sch Life Sci Hefei Peoples R China Chinese Acad Sci Inst Bot State Key Lab Systemat & Evolutionary Bot Beijing Peoples R China Southern Marine Sci & Engn Guangdong Lab Guangzho Guangzhou Guangdong Peoples R China

Genetic diversity and phylogenetic diversity reflect the evolutionary potential and history of species, respectively. However, the levels and spatial patterns of genetic and phylogenetic diversity of wildlife at the regional scale have largely remained unclear. Here, we performed meta-analyses of genetic diversity in Chinese terrestrial vertebrates based on three genetic markers and investigated their phylogenetic diversity based on a dated phylogenetic tree of 2461 species. We detected strong positive spatial correlations among mitochondrial DNA-based genetic diversity, phylogenetic diversity, and species richness. Moreover, the terrestrial vertebrates harbored higher genetic and phylogenetic diversity in South China and Southwest China than in other regions. Last, climatic factors (precipitation and temperature) had significant positive effects while altitude and human population density had significant negative impacts on levels of mitochondrial DNA-based genetic diversity in most cases. Our findings will help guide national-level genetic diversity conservation plans and a post-2020 biodiversity conservation framework.

关键词： Conservation

来源：评论

学校读者我要写书评

暂无评论

CODIS: Benchmarking Context-Dependent Visual Comprehension for Multimodal Large Language Models

arXiv

引用

arXiv 2024年

作者： Luo, fuwen chen, Chi Wan, Zihao Kang, Zhaolu Yan, Qidong Li, Yingjie Wang, Xiaolong Wang, Siyu Wang, Ziyue Mi, Xiaoyue Li, Peng Ma, Ning Sun, Maosong Liu, Yang Dept. of Comp. Sci. & Tech. Institute for AI Tsinghua University Beijing China Tsinghua University Beijing China Shanghai Artificial Intelligence Laboratory Shanghai China Jiangsu Collaborative Innovation Center for Language Competence Jiangsu China Key Laboratory of Linguistic and Cultural Computing Ministry of Education Northwest Minzu University China College of Software Jilin University China Institute of Computing Technology Chinese Academy of Sciences China

Multimodal large language models (MLLMs) have demonstrated promising results in a variety of tasks that combine vision and language. As these models become more integral to research and applications, conducting comprehensive evaluations of their capabilities has grown increasingly important. However, most existing benchmarks fail to consider that, in certain situations, images need to be interpreted within a broader context. In this work, we introduce a new benchmark, named as CODIS, designed to assess the ability of models to use context provided in free-form text to enhance visual comprehension. Our findings indicate that MLLMs consistently fall short of human performance on this benchmark. Further analysis confirms that these models struggle to effectively extract and utilize contextual information to improve their understanding of images. This underscores the pressing need to enhance the ability of MLLMs to comprehend visuals in a context-dependent manner. View our project website at https://***/CODIS. © 2024, CC BY.

关键词： Benchmarking

来源：评论

学校读者我要写书评

暂无评论

Highly efficient photocatalytic hydrogen production via porphyrin-fullerene supramolecular photocatalyst with donor-acceptor structure

引用

CHEMICAL ENGINEERING JOURNAL 2022年 444卷

作者： Liu, Liping chen, Xianjie Chai, Yongqiang Zhang, Weina Liu, Xiaolong Zhao, fuwen Wang, Zhuan Weng, Yuxiang Wu, Bo Geng, Hua Zhu, Yongfa Wang, Chunru Chinese Acad Sci Inst Chem Beijing Natl Lab Mol Sci Key Lab Mol Nanostruct & Nanotechnol Beijing 100190 Peoples R China Tsinghua Univ Dept Chem Beijing 100084 Peoples R China Southwest Univ Sci & Technol Sch Mat Sci & Engn State Key Lab Environm Friendly Energy Mat Mianyang 621010 Sichuan Peoples R China Capital Normal Univ Beijing Adv Innovat Ctr Imaging Theory & Technol Dept Chem Beijing 100048 Peoples R China Chinese Acad Sci Inst Phys Beijing Natl Lab Condensed Matter Phys CAS Key Lab Soft Matter Phys Beijing 100190 Peoples R China Univ Chinese Acad Sci Beijing 100049 Peoples R China

A novel tetraphenylporphyrin-C-60 supramolecular photocatalyst (SA-TPP-C-60) with donor-acceptor (D-A) structure is successfully constructed. Self-assembly of covalently-linked D-A molecule TPP-C-60 gives rise to SA-TPP-C-60 with highly-ordered layered D-A structure. TPP-C-60 molecule is characterized with strong D-A interaction, inducing a significantly larger molecular dipole moment (ca. 4.86 D) than the referential TPP molecule (only 0.04 D). In consequence, robust internal electric field (IEF) with 4.7 times enhancement is built up in SA-TPP-C-60, contributing to ultrafast photogenerated charge separation (similar to 0.5 ps) and enhanced charge transport. Notably, unprecedented long-lived photogenerated charge separation (tau = 26.3 ns) was observed in SA-TPP-C-60. Thus, the photocatalytic hydrogen evolution performance of SA-TPP-C-60 reached 10.69 mmol g(-1)h(-1) , which is about 80 times higher than SA-TPP. Briefly, this study sheds light on D-A structure engineering of supramolecular photocatalysts for high-performance photocatalytic applications.

关键词： Donor-acceptor structure Molecular dipole Robust internal electric field Ultrafast charge separation Photocatalytic hydrogen production

来源：评论

学校读者我要写书评

暂无评论

Failure analysis and revamping methods for loading threaded joints of raiseboring machine

Failure analysis and revamping methods for loading threaded ...

引用

作者： Guoye Jing fuwen Hu Yun chen Mine Construction Branch China Coal Research Institute National Engineering Laboratory for Deep Shaft Construction Technology in Coal Mine School of Mechanical and Material Engineering North China University of Technology Ningxia Tiandi Benniu Industrial Group Co. Ltd.

The process of raise boring(or back reaming) has been successfully employed for vertical mine *** technology has successfully evolved from early small borehole diameter less than 2m to large diameter greater than 8m without ***,in our developed raise boring machines,the threaded joints connecting reamers and drill rods suffered several fracture accidents during reaming in different geological and geotechnical *** this background,it is undoubtedly of great engineering value to explore the failure mechanisms and put forward systematic quality control and risk control *** fractured threaded joints were visually examined on-site,and then examined in the laboratory using fractographic and metallographic examination,mechanical testing and chemical composition ***,the end faces of threaded joints could not to be installed to fit the end faces of spindles due to over-specified tolerances or insufficient ***,it was found that the manganese(Mn) contents in material samples are higher than the national standards ***,the heat treatment of water-quenching of workpieces perhaps caused a certain degree of residual *** this systematic inspection suggested we should take overall improvements to eliminate the potential failure *** check and measurement of product and process performance,the cause-and-effect relationships undoubtedly were complex and ***,the component was redesigned using revamping methods including material compositions upgrade,fitting tolerances control,optimization of heat treatment ***,a systems approach and the institution of quality management system including increasing the preload,adding anti-dropping device and executing a Plan-Do-Check-Act cycle were *** this investigation and recommendations,the device has been in operation for more than two years without any problems.

关键词： Failure analysis and revamping methods for loading threaded joints of raiseboring machine

来源：评论

学校读者我要写书评

暂无评论

局限性脉络膜凹陷的临床研究进展

引用

眼科学报 2023年第7期38卷 512-517页

作者：刘雪英丁珊陈鸣(综述) 张富文(审校) 成都中医药大学眼科学院成都610075 成都中医大银海眼科医院成都610084 成都市中西医结合医院成都610041

局限性脉络膜凹陷(focal choroidal excavation,FCE)是表现为光感受器细胞层、视网膜色素上皮层向脉络膜层凹陷的眼底病变。发病机制多认为是先天脉络膜发育异常、炎症或感染。基于光学相干断层扫描(optical coherence tomography,OCT)... 详细信息

局限性脉络膜凹陷(focal choroidal excavation,FCE)是表现为光感受器细胞层、视网膜色素上皮层向脉络膜层凹陷的眼底病变。发病机制多认为是先天脉络膜发育异常、炎症或感染。基于光学相干断层扫描(optical coherence tomography,OCT),可将FCE从光感受器尖端与视网膜色素上皮层是否分离、形态特征或中央脉络膜厚度三种方式对其进行分类。FCE常合并脉络膜新生血管等疾病。该文对FCE的临床研究现状做一综述。

关键词：局限性脉络膜凹陷发病机制光学相干断层扫描临床表现

来源：评论

学校读者我要写书评

暂无评论

预应力胶合木-混凝土组合梁受弯性能的试验研究

引用

工业建筑 2024年第10期54卷 70-76页

作者：陈溪许清风张富文冷予冰王明谦陈玲珠上海市建筑科学研究院有限公司上海市工程结构安全重点实验室上海200032 上海建科预应力技术工程有限公司上海200032

进行了4组12个预应力胶合木-混凝土组合梁试件的受弯试验,试验参数为抗剪连接型式,包括凹槽连接、凹槽加螺钉连接、多种组合连接。结果表明:预应力胶合木-混凝土组合梁试件的主要破坏模式为木材的受弯破坏;对于同样采用凹槽加螺钉连接... 详细信息

进行了4组12个预应力胶合木-混凝土组合梁试件的受弯试验,试验参数为抗剪连接型式,包括凹槽连接、凹槽加螺钉连接、多种组合连接。结果表明:预应力胶合木-混凝土组合梁试件的主要破坏模式为木材的受弯破坏;对于同样采用凹槽加螺钉连接的组合梁试件,施加预应力后的平均受弯承载力提高了20.3%、破坏刚度提高了10.1%。组合梁试件破坏时,剪力连接处发生明显的滑移;采用凹槽加螺钉连接的组合梁试件在破坏时整体性和受弯承载力均优于其余两组组合梁试件,连接效果较好。

关键词：预应力胶合木-混凝土组合梁剪力连接受弯试验

来源：评论

学校读者我要写书评

暂无评论

Dual-emitting from Bi³⁺/Eu³⁺ co-activated akermanite phosphor for optical thermometric applications

引用

OPTICAL MATERIALS 2021年 116卷 111076-111076页

作者： Zhou, Liuyan Ye, Renguang Liu, fuwen Lin, Jianhua chen, Yanling Fu, Jie Guo, Weigang Deng, Degang Xu, Shiqing China Jiliang Univ Coll Mat & Chem Hangzhou 310018 Peoples R China China Jiliang Univ Inst Optoelect Mat & Devices Hangzhou 310018 Peoples R China Hangzhou Vocat & Tech Coll Hangzhou 310018 Peoples R China

In this paper, Ca2MgSi2O7: Bi3+, Eu3+ thermometric phosphors with dual-emitting centers were favorably designed. Phosphors were created by the approach of solid phase in high temperature condition. The inner phase structure and photoluminescence characteristics were investigated. The approaches of characterization including X-ray diffractometry, SEM, EDS mapping, ultraviolet-visible diffuse reflectance spectroscopy, as well as fluorescence spectrometry were applied. The influence of temperature on the photoluminescence characteristics of Ca2MgSi2O7: Bi3+, Eu3+ phosphors was systematically researched. The intensity ratio of P-3(1)-> S-1(0) purple luminescence of Bi3+ and D-5(0)-> F-7(2) red luminescence of Eu3+ is dependent on the temperature, which provides a method of optical sensing thermometry. Under the UV excitation of 287 nm, the maximum relative sensitivity (S-r) of this Ca2MgSi2O7: Bi3+, Eu3+ phosphor is 0.66%K-1 (at 533 K) and absolute sensitivity (S-a) gets to 0.0086 K-1 (at 573 K). The experimental phenomena were explained by the thermal-quenching mechanism. The garnered results provide an idea for the future development of luminescence intensity ratio (LIR) technology sensing materials on the basis of Ca2MgSi2O7.

关键词： Optical thermometric Ca2MgSi2O7: Bi3+ Eu3+ Dual-emitting centers Thermal-quenching mechanism

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：