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Metal Sealing Performance of Subsea X-tree Wellhead Connector Sealer

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Chinese Journal of Mechanical Engineering 2015年第3期28卷 649-656页

作者： ZHAO Honglin chen Rui LUO Xiaolan DUAN Menglan LU Yinghui fu Guowei TIAN Hongping YE Daohui College of Mechanical and Transportation Engineering China University of Petroleum Kingdream Public Limited Company

The metal sealing performance of subsea X-tree wellhead connectors is crucial for the safety and reliability of subsea X-trees. In order to establish the theoretical relation between metal sealing ring＇s contact stress and its structural parameters and working pressure, a mechanical analysis method for double-cone sealing of high pressure vessels is applied in analyzing the metal sealing ring under the condition of preload and operation. As a result, the formula of the unit sealing load for the metal sealing ring under operation with residual preload is shown in this paper, which ensures that the metal sealing ring has an excellent sealing effect and can prevent the metal sealing ring from yielding. Besides, while analyzing the sealing process of the metal sealing ring, the change rule of contact stress and working pressure is concluded here, putting forward that the structural parameters of the metal sealing ring are the major factors affecting the change rule. Finally, the analytical solution through theoretical analysis is compared with the simulation result through finite element analysis in a force feedback experiment, and both are consistent with each other, which fully verifies for the design and calculation theory on metal sealing ring＇s contact stress and its structural parameters and working pressure deduced in this paper. The proposed research will be treated as an applicable theory guiding the design of metal seal for subsea X-tree wellhead connectors.

关键词： sealing ring metal sealing mechanical analysis subsea X-tree wellhead connector subsea X-tree

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Electronic structures of the oxygenated diamond (100) surfaces

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Chinese Science Bulletin 2006年第20期51卷 2437-2443页

作者： liu Fengbin WANG Jiadao liu Bing LI Xuemin chen Darong State Key Laboratory of Tribology Tsinghua University Beijing 100084 China Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China

By means of first principles method on the basis of density functional theory (DFT), the equi- librium geometries and density of states (DOS) of the two oxygenated diamond (100) surfaces, bridging model and on-top model are calculated. The results indicate that there are no surface states located in the band gap of the bridging model of oxygenated dia- mond (100) surface, and the occupied surface states in the valence band are attributed to the non-bonded O 2p orbital, O 2p and C 2p bonding orbitals, and C 2p and H 1s bonding orbitals. By contrast, for the on-top model of oxygenated diamond (100) surface, the unoccupied surface states exist in the band gap, which originate from non-bonded C 2p and O 2p or- bitals. In addition, the occupied surface states in the valence band are induced by non-bonded O 2p or- bital and the C==O π bond.

关键词：钻石电子结构氧化摩擦密度功能理论剪切模型

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Sex difference in human diseases:mechanistic insights and clinical implications

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Signal Transduction and Targeted Therapy 2024年第10期9卷 4213-4245页

作者： Yuncong Shi Jianshuai Ma Sijin Li Chao liu Yuning liu Jie chen Ningning liu Shiming liu Hui Huang Department of Cardiology the Eighth Affiliated HospitalJoint Laboratory of Guangdong-Hong Kong-Macao Universities for Nutritional Metabolism and Precise Prevention and Control of Major Chronic DiseasesSun Yat-sen UniversityShenzhenChina Department of Radiotherapy Sun Yat-sen Memorial HospitalSun Yat-sen UniversityGuangzhouChina Department of Cardiology Guangzhou Institute of Cardiovascular DiseaseGuangdong Key Laboratory of Vascular Diseasesthe Second Affiliated HospitalGuangzhou Medical UniversityGuangzhouChina

Sex characteristics exhibit significant disparities in various human diseases,including prevalent cardiovascular diseases,cancers,metabolic disorders,autoimmune diseases,and neurodegenerative *** profiles and pathological manifestations of these diseases exhibit notable variations between *** underlying reasons for these sex disparities encompass multifactorial elements,such as physiology,genetics,and *** studies have shown that human body systems demonstrate sex-specific gene expression during critical developmental stages and gene editing *** genes,differentially expressed based on different sex,may be regulated by androgen or estrogen-responsive elements,thereby influencing the incidence and presentation of cardiovascular,oncological,metabolic,immune,and neurological diseases across ***,despite the existence of sex differences in patients with human diseases,treatment guidelines predominantly rely on male data due to the underrepresentation of women in clinical *** present,there exists a substantial knowledge gap concerning sex-specific mechanisms and clinical treatments for diverse ***,this review aims to elucidate the advances of sex differences on human diseases by examining epidemiological factors,pathogenesis,and innovative progress of clinical treatments in accordance with the distinctive risk characteristics of each disease and provide a new theoretical and practical basis for further optimizing individualized treatment and improving patient prognosis.

关键词： diseases clinical thereby

Static or dynamic pear shapes in radioactive nucleus ^(224)Rn?

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Nuclear Science and Techniques 2024年第11期35卷 164-173页

作者： Xian-Ye Wu Jin-Ze Cao Kun-Ning Zhao Zhong-Min liu Jian Xiang En-fu Zhou College of Physics and Communication Electronics Jiangxi Normal UniversityNanchang 330022China Jiangxi Provincial Key Laboratory of Advanced Electronic Materials and Devices Nanchang 330022China College of Physics and Electronic Engineering Chongqing Normal UniversityChongqing 401331China School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China

We report a comprehensive study on low-lying parity doublet states of ^(224)Rn by mixing both quadrupole-and octupoleshaped configurations in multireference covariant density functional theory,in which broken symmetries in configurations are restored using projection *** low-lying energy spectrum is reasonably reproduced when the shape fluctuations in both the quadrupole and octupole shapes are *** octupole transition strength in ^(224)Rn is found to be B(E3;3_(1)^(-)→0_(1)^(+))=43 W.u.,comparable to that in ^(224)Ra,whose data are 42(3)W.u..Our results indicate that ^(224)Rn shares similar low-energy structure with ^(224)Ra despite the excitation energy of first 3^(−)state of the former nucleus is higher than that of the *** study suggests ^(224)Rn is a candidate for the search for permanent electric dipole moment.

关键词： Covariant density functional theory Parity doublet bands Octupole correlations Electric transition strengths

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Characteristics and expression of the TCP transcription factors family in Allium senescens reveal its potential roles in drought stress responses

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BIOCELL 2023年第4期47卷 905-917页

作者： XIAOHONG fu JIE ZHAO DANDAN CAO chenGXING HE ZIYI WANG YIBEI JIANG JIANFENG liu GUIXIA liu College of Life Science Institute of Life Science and Green DevelopmentHebei UniversityBaoding071000China Hebei Innovation Center for Bioengineering and Biotechnology Hebei UniversityBaoding071002China College of Plant Protection China Agricultural UniversityBeijing100193China

Allium senescens,is an important economic and ecological grassland plant with drought-resistant characteristics.A TCP protein transcription factor is important in the regulation of plant development and adverse ***,the mechanism by which TCP transcription functions in drought resistance in Allium senescens is still not ***,we obtained a total of 190,305 transcripts with 115,562 single gene clusters based on RNA-Seq sequencing of Allium senescens under drought *** total number of bases was 97,195,096 bp,and the average length was 841.06 ***,we found that there were eight genes of the TCP family that showed an upregulated expression trend under drought stress in Allium *** carried out an investigation to determine the evolution and function of the AsTCP family and how they produce an effect in drought *** 14 AsTCP genes were confirmed and divided into class I and class II containing CIN and CYC/TBI subfamilies,*** also found that the expression of AsTCP17 was remarkably upregulated with drought ***,the transformation of AsTCP17 in Arabidopsis revealed that the protective enzymes,namely polyphenol oxidase(POD)and superoxide dismutase(SOD),were increased by 0.4 and 0.8 times,*** content was also increased,while the H2O2 and malondialdehyde(MDA)contents were *** assays with 3,3′-diaminobenzidine(DAB)also suggested that the AsTCP17 downregulates reactive oxygen species(ROS)*** addition,overexpression of the AsTCP17 affected the accumulation of drought-related hormones in plants,and the synthesis of *** expression of AtSVP and AtNCED3,related ABA synthesis pathway genes,indicated that the level of expression of AtSVP and AtNCED3 was obviously enhanced,with the overexpression of line 6 showing a 20.6-fold and 7.0-fold increase,*** together,our findings systematically analyze the AsTCPs family at the transcriptome expression

关键词： Allium senescens Drought stress TCP transcription factor ABA synthesis pathway

Preparation of high-quality resistant dextrin through pyrodextrin by a multienzyme complex

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Food Bioscience 2022年第3期47卷 986-991页

作者： Zhanzhi liu Jun liu Liqiong Ren Jing Wu Sheng chen State Key Laboratory of Food Science and Technology Jiangnan University1800 Lihu AvenueWuxi214122Jiangsu ProvinceChina School of Biotechnology and Key Laboratory of Industrial Biotechnology Ministry of Education Jiangnan University1800 Lihu AvenueWuxi214122Jiangsu ProvinceChina International Joint Laboratory on Food Safety Jiangnan University1800 Lihu AvenueWuxi214122Jiangsu ProvinceChina

As a soluble food raw material with a low calorie content,resistant dextrin (RD) has broad application prospects in the food *** enzymes (BEs),as a key enzyme for RD preparation,can break the α-1,4 glycosidic bonds of donor chains and reconstruct the cleaved chains to acceptor chains through the α-1,6 glycosidic *** with high transglucosidic activity toward amylopectin and short-chain substrates are urgently needed to increase the quality of ***,BE derived from Thermuobifida fusca (TfBE) was mined and *** optimal temperature and pH of the TfBE were 40 ℃ and 6.5,respectively.A total of 1500 U/g substrate TfBE reacted with 20% (w/v) pyrodextrin for 12 h,the ratio of α-1,4 to α-1,6 glycosidic bonds was changed from 3.52:1 to 2.33:1,and the content of enzyme-resistant components notably increased from 44.0% to 53.8%.furthermore,to make full use of receptor chains and small molecular sugars in the reaction system,a multienzyme complex of TfBE with *** α-cyclodextrin glucosyltransferase (TfCGTase),TfBE with TfCGTase and Aspergillus nidulans α-glucosidase (AnGS) was used to further increase the enzyme resistance of RD from 44.0% to 65.3% and 70.6%,*** developed multienzyme complex method could effectively contribute to improving the production quality and efficiency of RD preparation.

关键词： Pyrodextrin Resistant dextrin Branching enzyme α-Cyclodextrin glucosyltransferase α-Glucosidase Multienzyme complex

Research on Security of Key Algorithms in Intelligent Driving System

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Chinese Journal of Electronics 2019年第1期28卷 29-38页

作者： liu Shangdong WU Ye JI Yimu chen chen BI Qiang JIAO Zhipeng GONG Jian WANG Ruchuan School of Computer Science and Engineering Southeast University School of Computer Science Nanjing University of Posts and Telecommunications Jiangsu Provincial Key Laboratory of Computer Network Technology Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks

With the rapid development of the smart driving technology, the security of smart driving algorithms is becoming more and more important. Four core smart driving algorithms are determined by studying the architecture of smart driving algorithm. These algorithms comprise local path planning, pedestrian detection, lane detection and obstacle detection. The security issues of these algorithms are investigated by closely examining the work carried out by the algorithms. We found that there are vulnerabilities in all four algorithms. These vulnerabilities can cause abnormality and even road accidents for the smart cars. The final experiment shows that the vulnerabilities of these algorithms do exist under certain circumstances and therefore have high security risks. This study will lay a foundation to improve the security of the smart driving system.

关键词： Smart driving algorithm Local path planning Pedestrian detection Lane line detection Obstacle detection

Wave function in Quantum Cosmology of Bergmann-Wagoner Scalar-Tensor Gravitational Theory

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Chinese Physics Letters 1992年第12期9卷 673-676页

作者： liu Zixin chen Xiaojia Department of Physics He’nan Normal UniversityXinxiang 453002 also Institute of fundamental and Applied Science Zhengzhou 450052

The semiclassical cosmological wave function in quantum cosmology of the Bergrnann-Wagoner scalar tensor gravitational theory is given in Vilenkin approach and Hartle-Hawking *** initial condition for inflation is giv... 详细信息

关键词： tensor Tensor quantum

Au/LaVO_(4)Nanocomposite:Preparation,Characterization,and Catalytic Activity for CO Oxidation

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Nano Research 2008年第1期1卷 46-55页

作者： Junfeng liu Wei chen Xiangwen liu Kebin Zhou Yadong Li Department of Chemistry Tsinghua UniversityBeijing 100084China College of Chemistry and Chemical Engineering Graduate University of the Chinese Academy of SciencesBeijing 100049China

The size of the gold particles is a very important parameter to get active *** paper reports a novel colloidal deposition method to prepare Au/LaVO_(4)nanocomposite catalyst with monodispersed Au colloids and uniform LaVO_(4)nanoplates in nonpolar *** Au colloids with tunable size(such as 2,5,7,11,13,and 16 nm)and LaVO_(4)nanocrystals with well-defi ned shapes were pre-synthesized assisted with oleic acid/*** the following immobilization process,the particle size and shape of Au and LaVO_(4)were nearly ***-prepared Au/LaVO_(4)nanocomposite showed high catalytic activity for CO oxidation at room *** sizes of gold particles were well-defi ned before the immobilization process,size effect of gold particles was easy to be investigated and the results show that 5-nm Au/LaVO_(4)nanocomposite has the highest activity for CO *** synthetic method can be extended further for the preparation of other composite nanomaterials.

关键词： Au/LaVO_(4) nanocomposite colloidal deposition catalytic activity