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Orientation and strain rate dependent tensile behavior of single crystal titanium nanowires by molecular dynamics simulations

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Journal of Materials Science & Technology 2018年第5期34卷 864-877页

作者： Le chang chang-yu zhou Hong-Xi Liu Jian Li Xiao-Hua He School of Mechanical and Power Engineering Nanjing Tech University Nanjing 211816 China School of Mechanical Engineering Jiangsu University of Science and Technology Zhenjiang 212000 China

Molecular dynamics simulation was employed to study the tensile behavior of single crystal titanium nanowires（NWs）with[112^-0],[1^-100] and[0001]orientations at different strain rates from 10^8s^-1 to 10^11s^-*** strain rates are above 10^10s^-1,the state transformation from HCP structure to amorphous state leads to super plasticity of Ti NWs,which is similar to FCC *** strain rates are below 10^10s^-1,deformation mechanisms of Ti NWs show strong dependence on *** [112^-0] orientated NW.{101^-1} compression twins（CTs）and the frequently activated transformation between CTs and deformation faults lead to higher plasticity than the other two orientated ***,tensile deformation process along [112^-0] orientation is insensitive to strain *** [1^-100] orientated NW,prismaticslip is the main deformation mode at 10^8s^-*** the strain rate increases,more types of dislocations are activated during plastic deformation ***[0001]orientated NW,{101^-2} extension twinning is the main deformation mechanism,inducing the yield stress of [0001] orientated NW,which has the highest strain rate *** number of initial nucleated twins increases while the saturation twin volume fraction decreases nonlinearly with increasing strain rate.

关键词： Molecular dynamics Single crystal titanium nanowires Strain rate Orientation Plastic deformation mechanisms

Temperature-Dependent SRS Behavior of 316L and Its Constitutive Model

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Acta Metallurgica Sinica(English Letters) 2018年第3期31卷 234-244页

作者： Jian Peng Jian Peng Kai-Shang Li Jun-Feng Pei chang-yu zhou School of Mechanical Engineering Changzhou UniversityChangzhou 213164 China Jiangsu Key Laboratory of Green Process Equipment Changzhou University Changzhou 213164 China School of Mechanical and Power Engineering Nanjing TechUniversity Nanjing 210009 China

The strain rate sensitivity（SRS）and temperature sensitivity（TS）of 316L austenitic stainless steel were investigated by constant strain rate test（CSRT）and strain rate jump test（SRJT）under four temperatures（293,373,473 and 573 K）and four strain rates（5 ×10^-4/s,1 × 10^-3/s,5 × 10^-3/s and 1 × 10^-2/s）.The results show that temperature sensitivity（TS）indexes at different strain rates are coincidence to be negative,related to temperature *** the contrary,SRS indexes change from positive to negative with the increase in temperature associated with dynamic strain aging（DSA）.Moreover,based on the comparison between CSRT and SRJT,SRS and TS indexes obtained by two methods agree *** proves that the SRJT can describe the SRS and TS phenomenon of 316L ***,the effects of tem-perature and strain rate on fracture mechanism were *** last,an improved Johnson-Cook model was proposed to consider the temperature-dependent SRS behavior of 316L.

关键词： Strain rate sensitivity Strain rate jump test Improved Johnson-Cook model

Effect of isothermal temper embrittlement and subsequent hydrogen embrittlement on tensile properties of 2.25Cr-1Mo-0.25V base metal and welded metal

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Journal of Iron and Steel Research International 2021年第11期28卷 1426-1438页

作者： Zhi-peng Shen Wei Fu Ling-rui Kong Han-han Ma Xiao-hua He Xiao-chun yu chang-yu zhou School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211816JiangsuChina Jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipment Nanjing 211816JiangsuChina

2.25Cr–1Mo–0.25V base metal(BM)and welded metal(WM)with different temper embrittlement states were obtained by isothermal temper embrittlement *** ductile–brittle transition temperature and the carbide size of temper embrittled 2.25Cr–1Mo–0.25V BM and WM increased with the isothermal tempering *** increase in temper embrittlement time leads to a decrease in yield strength(YS)and ultimate tensile strength(UTS).Hydrogen embrittlement(HE)can decrease the ductility and increase YS and UTS of the *** hydrogen embrittlement sensitivity and microstructure analysis both show a combined effect of HE and temper *** deeper the temper embrittlement,the more sensitive the material to *** the hydrogen content in the material is low,the WM is less susceptible to HE due to its welding defects.

关键词： 2.25Cr–1Mo–0.25V base metal Temper embrittlement Hydrogen embrittlement Mechanical property Combined effect

Spontaneous pneumomediastinum in an elderly COVID-19 patient:A case report

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World Journal of Clinical Cases 2020年第16期8卷 3573-3577页

作者： Ning Kong Chen Gao Mao-Sheng Xu yuan-Liang Xie chang-yu zhou Department of Radiology The First Clinical Medical College of Zhejiang Chinese Medical UniversityHangzhou 310053Zhejiang ProvinceChina Department of Radiology The First Affiliated Hospital of Zhejiang Chinese Medical UniversityHangzhou 310006Zhejiang ProvinceChina Department of Radiology Central Hospital of WuhanTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430014Hubei ProvinceChina

BACKGROUND Spontaneous pneumomediastinum(SPM)is more common in young adults,usually caused by external factors like *** causes symptoms such as chest pain or dyspnea,but it is rare to see elderly patients who develop *** we report the case of an elderly patient diagnosed with coronavirus disease 2019(COVID-19)who neither got mechanical ventilation nor had chest trauma but were found to develop SPM for unknown *** SUMMARY A 62-year-old man complained of a 14-d history of fever accompanied by dry cough,shortness of breath,wheezing,myalgia,nausea,and ***-time fluorescence polymerase chain reaction confirmed the diagnosis of *** patient was treated with supplementary oxygen by nasal cannula and gamma *** symptomatic treatments included antibacterial and antiviral *** day 4 of hospitalization,he reported sudden onset of *** day 6,he was *** day 12,the patient reported worsening right-sided chest pain which eventually progressed to bilateral chest *** was diagnosed with SPM,with no clear trigger *** treatment was *** follow-up,the pneumomediastinum had resolved and the patient recovered without other *** We presume that aging lung changes and bronchopulmonary infection play an important part in the onset of SPM in COVID-19,but severe acute respiratory syndrome may represent a separate pathophysiologic mechanism *** the incidence of SPM in elderly patients is low,clinicians should be alert to the possibility of SPM in those infected with severe acute respiratory syndrome coronavirus 2 for life-threatening complications such as cardiorespiratory arrest may occur.

关键词： Aging Spontaneous pneumomediastinum COVID-19 SARS Case report

Atypical adult-onset Still’s disease with an initial and sole manifestation of liver injury: A case report and review of literature

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World Journal of Clinical Cases 2021年第1期9卷 224-231页

作者： Fan yu Shao-You Qin chang-yu zhou Lu Zhao Yan Xu Er-Na Jia Jiang-Bin Wang Department of Gastroenterology and Hepatology China-Japan Union Hospital of Jilin UniversityChangchun 130033Jilin ProvinceChina Department of Digestive Heze Municipal HospitalHeze 274000Shandong ProvinceChina

BACKGROUND Adult-onset Still's disease(AOSD)typically presents with a high spiking fever,polyarthritis,transient maculopapular rash,neutrophilic leukocytosis,and *** has a wide spectrum of clinical symptoms ranging from mild to severe,with extensive involvement of almost every *** liver involvement in the form of increased hepatic enzymes and bilirubin is common,no AOSD case with liver involvement as the initial manifestation of AOSD has been *** SUMMARY A 35-year-old woman presented to the hepatology department with progressively worsening jaundice for one *** chemistry tests revealed a significantly increased liver enzymes and bilirubin *** that the clinical examination was unremarkable,liver biopsy was considered because the patient had a history of AOSD 6 years *** histopathology revealed that most hepatic lobules were still *** necrosis was observed around most central veins.A few bridging necrotic zones were also *** of multiple plasma cells were observed in the necrotic zone,and the reticular scaffold was still ***,no obvious fibrosis was observed in the portal *** mixed inflammatory cell infiltration was noted in the interstitium of the portal *** examination was unremarkable except for a remarkably high level of ***,a presumptive diagnosis of liver injury secondary to AOSD was *** hepatic involvement responded well to glucocorticoid *** This case highlights that hepatic involvement as an initial and sole manifestation could be a pattern of relapsed *** diagnosis of AOSD should be considered in the case of nonresolving liver injury after the exclusion of common etiologies for liver diseases.A liver biopsy can be useful for the differential diagnosis of liver injury associated with AOSD.

关键词： Adult-onset Still's disease Liver injury Liver biopsy Histopathology Glucocorticoid treatment Case report

Low cycle fatigue behavior of zirconium−titanium−steel composite plate

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Transactions of Nonferrous Metals Society of China 2022年第5期32卷 1530-1547页

作者： Bin-bin zhou Peng yu Le chang chang-yu zhou Cheng YE Bo-jun ZHANG Engineering Technology Training Center Nanjing Vocational University of Industry TechnologyNanjing 210023China School of Mechanical and Power Engineering Nanjing Tech UniversityNanjing 211816China Jiangsu Key Lab of Design and Manufacture of Extreme Pressure Equipment Nanjing 210028China Technology Research and Development Department Nanjing Boiler and Pressure Vessel Inspection InstituteNanjing 210028China

The low cycle fatigue behavior of zirconium−titanium−steel composite plate under symmetrical and asymmetric stress control was *** effects of mean stress and stress amplitude on cyclic deformation,ratcheting effect and damage mechanism were discussed in *** results show that under symmetric stress control,the forward ratcheting deformation is *** asymmetric stress control,the ratcheting strain increases rapidly with mean stress and stress amplitude *** high stress amplitude,the influence of mean stress is more *** addition,by studying the variation of strain energy density,it is found that the stress amplitude mainly promotes the fatigue damage,while the mean stress leads to the ratcheting *** addition,fractographic observation shows that the crack initiates in the brittle metal compound at the interface,and the steel has higher resistance to crack ***,the accuracy of life prediction model considering ratcheting effect is discussed in detail,and a high-precision life prediction model directly based on mean stress and stress amplitude is proposed.

关键词： zirconium−titanium−steel composite plate low cycle fatigue behavior fatigue damage mean stress ratcheting effect life prediction model

Landscape changes from 1974 to 1995 in the Upper Minjiang River Basin, China

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Pedosphere 2006年第3期16卷 398-405页

作者： HE Xing-yuan ZHAO Yong-Hua HU yuan-Man chang yu zhou Qi-Xing Institute of Applied Ecology the Chinese Academy of Sciences Shenyang 110016 （China） College of Earth Science ＆ Land Resources Management Chang＇an University Xi＇an 710054 （China） Graduate School of the Chinese Academy of Sciences Beijing 100039 （China）

Landscape changes were traced over the 20 years from 1974 to 1995 in the upper Minjiang River basin, one of the most important forest regions in China, based on satellite image interpretation to provide basic data for local decision-making as well as sustainable landscape use and management. Results revealed that landscape from 1974 to 1995 changed at the regional scale as the area of forestland decreased, while cropland, shrubland, economic forest, grassland, and built-up land increased. Landscape changes mainly occurred in forestland, shrubland, grassland, economic forest, and built-up land. Moreover, the changes among forestland, shrubland, and grassland were the largest, influencing the whole characteristics of the changes in the basin. Analysis of the changes between 1974 and 1995 in the study area indicated that landscape heterogeneity and fragmentation increased, whereas landscape connectivity decreased. There were multiple reasons for landscape changes. A principal component analysis (PCA) was used to quantitatively study driving forces of landscape changes. The PCA results showed that economic and population factors were the principal driving forces of landscape changes from 1974 to 1995 in the upper Minjiang River basin, and that PCA was a suitable method for investigating driving forces of landscape changes.

关键词： driving forces landscape change satellite image quantification principal component analysis

Influence of polarization extinction ratio on distributed polarization coupling detection

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Optoelectronics Letters 2008年第4期4卷 292-294页

作者： XU Tlan-hua TANG Feng JING Wen-cai ZHANG Hong-xia JIA Da-gong yu chang-song zhou Ge ZHANG Yi-mo College of Precision Instrument ＆ Optoelectronics Engineering Key Laboratory for Optoelectronics Information and Technical Science of National Ministry of Education Tianjin University Tianjin 300072 China

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson *** technique usually requires that only one polarization mode is ***,in practical measurement,the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF,so the influence of the polarization extinction ratio should be *** on the polarization coupling theory,the influence of the incident polarization extinction on the measurement result is evaluated and analyzed,and a method for distributed polariza-tion coupling detection is developed when both two orthogonal eigenmodes are excited.

关键词：分布式偏振耦合检测极化衰落率白光迈克逊干涉计偏振模式

ONE LIMIT THEOREM, OPTIMAL CRITERION AND EXISTENCE THEOREM OF THE DUAL NONLINEAR PROGRAM

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Chinese Science Bulletin 1989年第2期34卷 95-99页

作者：王长钰周惠山 Institute of Operations Research Qufu Normal University

R. T. Rockafellar built a new general convex dual theory by introducing the conjugate function and the perturbation function. Following him, many other authors obtained some important results in generalized convex dua... 详细信息

关键词： primal program dual program characteristic function perturbation parameter.