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Effect of cooling rate on microstructure and mechanical properties of CB2 tempered martensitic steel

China Foundry 2020年第2期17卷 158-166页

作者： Yu-lin Ma Yue Liu Li-ping zhang Xu Jiang chun-ming Liu School of Materials Science and Engineering Northeastern UniversityShenyang 110189China The Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) Northeastern UniversityShenyang 110189China

The cooling rate of casting has a significant effect on microstructure and mechanical properties of *** 9Cr-1.5Mo-1Co cast steel,referred to as CB2,is one of the most promising alloys for various cast components to be used under ultrasupercritical *** this study,HRTEM,SEM,and XRD methods were used for qualitative and quantitative analyses of contents,phases,and sizes of the inclusions and precipitates,as well as microstructure observation of the tempered martensitic steel at different cooling *** tensile tests were conducted to characterize the material mechanical *** show that the size of the boron nitride and precipitate,the width of the martensite lath and the content of theδ-ferrite are reduced as the cooling rate increases from 5-8℃·min^-1(CB2-S steel)to 50-60℃·min^-1(CB2-F steel).The precipitates are mainly composed of M23C6 and a small amount of *** average diameters of the M23C6 precipitates in CB2-F and CB2-S are 202 nm and 209 nm,*** inclusions are mainly composed of BN,Al2O3 and MnO2,and the inclusion ratios are 0.1969%for the CB2-F and 0.06556%for CB2-S *** average martensite lath widths of CB2-F and CB2-S steels are 289 nm and 301 nm,***,the M3C having a diameter of about 150 nm and a thickness of 20 nm is observed in theδ-ferrite of the tempered CB2-S *** presence of theδ-ferrite reduces the precipitation strengthening and dislocation density in CB2-S *** addition,the lower cooling rate stabilizes theδ-ferrite structure at room temperature.

关键词： tempered martensitic steel casting microstructure M23C6 mechanical properties inclusions δ-ferrite

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Secure Beamforming Design for SWIPT in Cooperative D2D Communications

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China Communications 2017年第1期14卷 20-33页

作者： Li Jiang Cheng Qin Xixi zhang hui Tian State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunicationsand Science and Technology on Information Transmission and Dissemination in Communication Networks LaboratoryBeijing100876China

In device-to-device(D2D) communications, device terminal relaying makes it possible for devices in a network to function as transmission relays for each other to enhance the spectral efficiency. In this paper we consider a cooperative D2D communication system with simultaneous wireless information and power transfer(SWIPT). The cooperative D2D communication scheme allows two nearby devices to communicate with each other in the licensed cellular bandwidth by assigning D2D transmitters as half-duplex(HD) relay to assists cellular downlink transmissions. In particular, we focus on secure information transmission for the cellular users when the idle D2D users are the potential eavesdroppers. We aim to design secure beamforming schemes to maximize the D2D users data rate while guaranteeing the secrecy rate requirements of the cellular users and the minimum required amounts of power transferred to the idle D2D users. To solve this non-convex problem, a semi-definite programming relaxation(SDR) approach is adopted to obtain the optimal solution. Furthermore, we propose two suboptimal secure beamforming schemes with low computational complexity for providing secure communication and efficient energy transfer. Simulation results demonstrate the superiority of our proposed scheme.

关键词： device-to-device(D2D) communications half-duplex relaying physical layer security secure beamforming simultaneous wireless information and power transfer

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Numerical simulation of the interfacial stress between epoxy resin and metal conductor of power equipment during epoxy curing

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High Voltage 2022年第5期7卷 903-915页

作者： Chuang Wang Gang Zhou Qing Sun Chi Chen Zaiqin zhang hui Li ZongRen Peng School of Electrical Engineering Xi'an University of TechnologyXi'anChina State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina

There are many metal and epoxy resin interfacial structures in power equipments,which can generate interfacial stress concentrations and may induce accidents due to epoxy *** this paper,through simplifying interface structure into a coaxial cylindrical model,the formation mechanism of interfacial stress concentration of this interface structure was studied during epoxy resin curing *** strain and temperature at the interface were measured by the strain and temperature measurement *** a model for calculating the interface stress distribution was established,including the heat conduction module,curing dynamics module and curing deformation *** validity of the model was verified by comparing the calculated results with the measured *** addition,the air gap defects at the interface,appearing after the curing process,were *** results show that,after the curing process,the first principal stress at the centre of the interface gradually increases from the centre to the edge,reaching 41.06 and 40.20 MPa at the upper and lower edges *** existence of air gap leads to partial discharge at low *** calculation model can be extended to the stress prediction between the metal and epoxy resin in other power equipments.

关键词： resin curing interfacial

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Aerobic exercise improves ejaculatory behaviors and complements dapoxetine treatment by upregulating the BDNF-5-HT duo:a pilot study in rats

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Asian Journal of Andrology 2023年第5期25卷 637-642页

作者： Yuan-Yuan Huang Dang-Wei Peng Qiu-Shi Liu hui Jiang Xian-Sheng zhang Department of Urology The First Affiliated Hospital of Anhui Medical UniversityHefei 230022China Department of Urology Peking University First HospitalBeijing 100000China Andrology Center Peking University First HospitalBeijing 100000China Institute of Urology Peking UniversityBeijing 100000China

Accumulating evidence has revealed many clues that regular aerobic exercise benefits brain health and *** aims of this study were to explore the effect of aerobic exercise on ejaculatory behaviors,as well as to make a preliminary assessment of aerobic exercise as a complementary strategy to dapoxetine treatment in rapid *** tests of rats and a treadmill training protocol were performed in this *** total,12 rapid ejaculators were selected on the basis of ejaculation distribution theory and randomly assigned to 4 groups:control(Ctrol)group,aerobic exercise(Ex)group,dapoxetine(Dapo)group,and Ex+Dapo *** evaluated the changes in ejaculatory parameters in the 4 *** in biological markers,including serum corticosterone,serotonin(5-HT),and brain-derived neurotrophic factor(BDNF)of the raphe nucleus,were determined by enzyme-linked immunosorbent assay(ELISA).The primary finding of our study was that both aerobic exercise and acute dapoxetine could enhance ejaculation control and prolong ejaculation latency in rapid ejaculator *** ejaculation delay effect of aerobic exercise was nearly equivalent to that of acute *** addition,both aerobic exercise and dapoxetine treatment could lead to increased expression of BDNF and 5-HT in the raphe nucleus of rapid ***,the two interventions,when applied together,may further upregulate the expression of BDNF-5-HT duo in a complementary *** study highlights the positive effects of aerobic exercise on ejaculation *** aerobic exercise might be a promising complementary treatment to dapoxetine in rats.

关键词： aerobic exercise animal model brain-derived neurotrophic factor premature ejaculation raphe nucleus serotonin

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Applying the Hidden Markov Model to Analyze Urban Mobility Patterns: An Interdisciplinary Approach

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Chinese Geographical Science 2021年第1期31卷 1-13页

作者： LOO Becky P Y zhang Feiyang HSIAO Janet H CHAN Antoni B LAN hui Department of Geography the University of Hong KongHong Kong 999077China Department of Psychology the University of Hong KongHong Kong 999077China Department of Computer Science the City University of Hong KongHong Kong 999077China

With the emergence of the Internet of Things(IoT), there has been a proliferation of urban studies using big data. Yet, another type of urban research innovations that involve interdisciplinary thinking and methods remains underdeveloped. This paper represents an attempt to adopt a Hidden Markov Model(HMM) toolbox developed in Computer Science for the analysis of eye movement patterns in Psychology to answer urban mobility questions in Geography. The main idea is that both people’s eye movements and travel behavior follow the stop-travel-stop pattern, which can be summarized using HMM. Methodological challenges were addressed by adjusting the HMM to analyze territory-wide travel survey data in Hong Kong, China. By using the adjusted toolbox to identify the activitytravel patterns of working adults in Hong Kong, two distinctive groups of balanced(38.4%) and work-oriented(61.6%) lifestyles were identified. With some notable exceptions, working adults living in the urban core were having a more work-oriented lifestyle. Those with a balanced lifestyle were having a relatively compact zone of non-work activities around their homes but a relatively long commuting distance. Furthermore, working females tend to spend more time at home than their counterparts, regardless of their marital status and lifestyle. Overall, this interdisciplinary research demonstrates an attempt to integrate spatial, temporal, and sequential information for understanding people’s behavior in urban mobility research.

关键词： activity-travel pattern urban mobility activity sequences cluster analysis Hidden Markov Model

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Acetic acid-assisted mild dealloying of fine CuPd nanoalloys achieving compressive strain toward high-efficiency oxygen reduction and ethanol oxidation electrocatalysis

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Carbon Energy 2023年第7期5卷 112-120页

作者： Danye Liu Yu zhang hui Liu Peng Rao Lin Xu Dong Chen Xinlong Tian Jun Yang State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijingChina State Key Laboratory of Marine Resource Utilization in South China Sea Hainan Provincial Key Lab of Fine ChemistrySchool of Chemical Engineering and TechnologyHainan UniversityHaikouChina Jiangsu Key Laboratory of New Power Batteries School of Chemistry and Materials ScienceJiangsu Collaborative Innovation Centre of Biomedical Functional MaterialsNanjing Normal UniversityNanjingChina Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina Nanjing IPE Institute of Green Manufacturing Industry NanjingJiangsuChina

Dealloying by which the transition metal is partially or completely leached from an alloy precursor is an effective way to optimize the fundamental effects for further enhancing the electrocatalysis of a ***,to address the deficiencies associated with the commonly used dealloying methods,for example,electrochemical and sulfuric acid/nitric acid treatment,we report an acetic acid-assisted mild strategy to dealloy Cu atoms from the outer surface layers of CuPd alloy nanoparticles to achieve high-efficiency electrocatalysis for oxygen reduction and ethanol oxidation in an alkaline *** leaching of Cu atoms by acetic acid exerts an additional compressive strain effect on the surface layers and exposes more active Pd atoms,which is beneficial for boosting the catalytic performance of a dealloyed catalyst for the oxygen reduction reaction(ORR)and the ethanol oxidation reaction(EOR).In particular,for ORR,the CuPd nanoparticles with a Pd/Cu molar ratio of 2:1 after acetic dealloying show a half-wave potential of 0.912 V(***)and a mass activity of 0.213 AmgPd^(-1) at 0.9 V,respectively,while for EOR,the same dealloyed sample has a mass activity and a specific activity of 8.4 Amg^(-1) and 8.23 mA cm^(-2),respectively,much better than their dealloyed counterparts at other temperatures and commercial Pd/C as well as a Pt/C catalyst.

关键词： compressive strain effect dealloying electrocatalysis ethanol oxidation reaction oxygen reduction reaction

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Intrahepatic biliary cystadenoma:A case report

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World Journal of Clinical Cases 2020年第22期8卷 5670-5677页

作者： Ruo-Mei Xu Xiao-Ru Li Lin-Han Liu Wen-Qiao Zheng hui Zhou Xiao-chun Wang College of Medical Imaging Shanxi Medical UniversityTaiyuan 030001Shanxi ProvinceChina Department of Radiology First Hospital of Shanxi Medical UniversityTaiyuan 030001Shanxi ProvinceChina

BACKGROUND Biliary cystadenoma(BCA)is a rare benign tumor,accounting for only 5%of reported cystic lesions of the *** its potential for malignancy and high rate of recurrence,surgical resection is the preferred ***,early and accurate preoperative diagnosis is critical to the choice of *** here report the first male case of BCA in our hospital,diagnosed by our team and confirmed by pathological *** article aims to improve the understanding of this disease and help make a correct diagnosis to better manage *** SUMMARY A 58-year-old man with irregular abdominal discomfort came to our clinic and was found to have a distended abdomen during physical *** tomography and magnetic resonance imaging both showed a huge cystic mass in the *** patient underwent left hepatic lobectomy,cholecystectomy,and liver cyst fenestration,and most of the masses had decreased in size as of the 6-mo *** pathological diagnosis was consistent with BCA,and no recurrence was detected after the *** occurred mainly in middle-aged *** the best of our knowledge,this patient is the 11th male case of BCA reported in the *** The combination of magnetic resonance imaging and magnetic resonance cholangiopancreatography is of great significance for the early accurate diagnosis of the disease and the choice of surgical methods.

关键词： Cystadenoma Liver cystic lesions Magnetic resonance imaging Diagnosis Imaging Case report

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Influence of sulfate on the generation of bitumen components from kerogen decomposition during catagenesis

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Petroleum Science 2021年第6期18卷 1611-1618页

作者： Jia Wu Wen Qi Fu-Jie Jiang Qing-Yong Luo chun-Lin zhang Huan-Zhen Hu Zi Wang Qi-Sheng Ma Yong-chun Tang State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249China College of Geoscience China University of Petroleum(Beijing)Beijing102249China PetroChina Research Institute of Petroleum Exploration&DevelopmentdNorthwest LanzhouGansu730020China PetroChina Research Institute of Petroleum Exploration&Development Beijing100083China University of Southern California Los AngelesCA90089USA Power Environmental Energy Research Institute CovinaCA91722USA

High-quality source rocks in saline lacustrine or marine sedimentary environments often show early peak petroleum generation and enhanced hydrocarbon yields,which have conventionally been attributed to organosulfur-enhanced thermal decomposition of kero ***,there is increasing awareness that the coexisting inorganic salts,particularly sulfates,might also contribute to the acceleration of petroleum *** this study,we investigated the influence of sulfates on the thermal decomposition of kerogen sampled from the Pingliang Formation in the Ordos *** results demonstrate that the kerogen samples mixed with sulfate generate more hydrocarbons with a lower peak production temperature than their sulfate-free *** chemical analysis revealed that the presence of sulfates significantly facilitated the generation of resins and asphaltenes at temperatures below 350℃,corresponding in our simulations to the early stage of petroleum generation(Easy%R_o <1.0%).We hypothesize that sulfates can promote the fragmentation of kerogen via direct thermochemical oxidation into a complex mixture of bitumen components that consist mostly of compounds typically encountered in the classical resin and asphaltene *** findings reveal a new reaction paradigm between sulfates and organic macromolecules that could offer useful guidance in the exploration for low-maturity oils.

关键词： Sulfate Kerogen Thermal decomposition Resins and asphaltenes Redox reactions

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Gastric neuroendocrine tumors in a BRCA2 germline mutation carrier:A case report

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World Journal of Gastrointestinal Oncology 2023年第8期15卷 1497-1504页

作者： hui-Fang zhang Yi Zheng Xue Wen Jing Zhao Jun Li Department of Pathology The First Affiliated HospitalMedical CollegeZhejiang UniversityHangzhou 310000Zhejiang ProvinceChina

BACKGROUND The molecular changes present in gastric neuroendocrine tumors(NETs)include a loss of heterozygosity or mutation of MEN1,CDKN1B gene mutation,P27 heterozygous mutation,and ATP4A gene missense *** identified and are the first to report a case of type 1 histamine-producing enterochromaffin-like cell NETs(ECL-cell NETs)with a BRCA2 gene germline *** SUMMARY The patient had a history of iron-deficient anemia for 5 years,and gastroscopic examination indicated multiple gastric ***,the patient underwent distal ***,multifocal tumor cells were found in the mucosa and submucosa;tumor cells were organoid and arranged in nests and cords,and the stroma was rich in *** surrounding gastric mucosa showed atrophy with mild intestinal metaplasia or pseudopyloric gland *** cells could be seen with diffuse linear,nodular,and adenomatous ***,the tumor cells diffusely expressed cytokeratin,chromogranin,synaptophysin,and ***-genome highthroughput molecular sequencing revealed a pathogenic germline mutation in the BRCA2 gene,a heterozygous germline frameshift mutation in exon 11,c.6443_6444del(p.S2148Yfs*2).The final diagnosis was gastric type 1 ECL-cell NETs with a BRCA2 gene germline mutation,accompanied by autoimmune *** This is the first report of a case of type 1 gastric ECL-cell NETs with a pathogenic germline mutation of the BRCA2 *** findings of this report will expand the germline mutation spectrum of gastric NETs and increase the understanding of the molecular changes present in these tumors for their improved diagnosis in the future.

关键词： Gastric Neuroendocrine tumor Enterochromaffin-like cell neuroendocrine tumors Type 1 enterochromaffin-like cell neuroendocrine tumors BRCA2 Germline mutation Case report

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Influence of formation in-situ stress on mechanical heterogeneity of shale through grid nanoindentation

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Petroleum Science 2022年第1期19卷 211-219页

作者： Mao Sheng Shi-Zhong Cheng Zhao-hui Lu Ye zhang Shou-Ceng Tian Gen-Sheng Li College of Petroleum Engineering China University of Petroleum-Beijing102249PR China National and Local Joint Engineering Research Center of Shale Gas Exploration and Development Chongqing401120PR China

Mechanical heterogeneity is a major characteristic of the organic-rich *** relation between mechanical heterogeneity and formation in-situ stress has been seldomly addressed but important to understand hydraulic fracture propagation,wellbore stability,and hydrocarbon *** this paper,the grid nanoindentation technique was used to characterize the heterogeneity of the mechanical properties of Longmaxi organic-rich shales from various burial depths and in-situ *** measured elastic modulus and hardness of each sample are deconvolved into three phases including soft phase,medium stiff phase and stiff phase according to mineral *** the burial depth and corresponding in-situ stress increase,the overall elastic modulus and hardness of the sample ***,the percentage of soft minerals decreases,and the probability distribution tends to concentrate through 95%confidence interval evaluation which demonstrates weakened ***,SEM images provide evidence that extended cracking,initiated cracking,crushing and ductile deforming always occur around indentation *** confirms that even under deep buried depth and high in-situ stress,brittle fracture and ductile deformation can exist *** paper demonstrates the influence of in-situ stress on the heterogeneity of shale micromechanics.

关键词： Shale Heterogeneity Elastoplasticity Nanoindentation

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