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Plasticity Induced by Twin Lamellar Structure in Magnesium Alloy

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Journal of Materials Science & Technology 2013年第12期29卷 1123-1128页

作者： xiyan zhang Chao Lou Jian Tu Qing Liu School of Materials Science and Engineering Chongqing University

Effect of {10-12} twins on the mechanical properties of magnesium alloy has received considerable research interest. A hot-rolled AZ31 Mg alloy sheet was subjected to dynamic plastic deformation with the aim of introducing {10-12} twin lamellar structure. It has been found that higher strength and better ductility are obtained when tensile loading is perpendicular to the c axis of twin region of the twin lamellar structured sample, indicating that the plasticity improvement caused by twins depends on the special strain path. The fracture morphology of the twin lamellar structured sample shows a dimple fracture mode under tensile loading perpendicular to the c axis, while the cleavage fracture with river pattern has been observed in other fractured samples. Above experimental results indicate that the interaction of dislocations and twin lamellae may play an important role in improving mechanical properties of Mg alloy.

关键词： Magnesium alloy Twin lameilar structure Mechanical behavior Plasticity

Characteristics of Twin Lamellar Structure in Magnesium Alloy during Room Temperature Dynamic Plastic Deformation

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Journal of Materials Science & Technology 2014年第1期30卷 41-46页

作者： Chao Lou xiyan zhang Gaolin Duan Jian Tu Qing Liu School of Materials Science and Engineering Chongqing UniversityChongqing 400030China

The microstructures of the as-rolled magnesium alloy subjected to dynamic plastic deformation along the rolling direction have been *** one{101-2}twin variant or a twin variant pair is activated in a grain,leading to a parallel{101-2}twin lamellar *** the stage of twinning-dominated deformation(ε〈-8%),lamellar thickness decreases significantly with strain,from 5.55 to 2.49 *** evolution of lamellar thickness during deformation is directly related to{1012}twin *** plastic strain is greater than-8%,the twin lamellar structure disappears because the volume fraction of twins almost saturates at a value of-90%.

关键词： Magnesium alloy {1012}hvin lameUa Lamellar thickness Strain

Precise determination of the α → α+β phase transformation temperature of Zr-1.0Sn-0.3Nb-0.3Fe alloy

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Science China(Technological Sciences) 2013年第1期56卷 60-65页

作者： QIU RiSheng LUAN BaiFeng CHAI LinJiang zhang xiyan LIU Qing College of Materials Science and Engineering Chongqing University

In this investigation,differential scanning calorimetry(DSC) and metallographic experiments were performed to study α→α +β phase transformation temperature in a Zr-1.0Sn-0.3Nb-0.3Fe *** deconvolution and extrapolation methods to determine the α→α+β phase transformation temperature in DSC experiment were appropriate for the Zr ***,precise determination of α→α+β phase transformation temperature was carried out by back-scattered electron imaging(BSEI) and electron back-scattered diffraction(EBSD) characterization *** α→α+β phase transformation temperature of the Zr-1.0Sn-0.3Nb-0.3 Fe alloy was determined to be 765-770°C.

关键词： phase transformation temperature deconvolution extrapolation back-scattered electron imaging(BSEI) electron back-scattered diffraction(EBSD)

A Large-Scale Cross-Sectional Study on Mental Health Status Among Children and Adolescents - Jiangsu Province, China, 2022

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China CDC weekly 2023年第32期5卷 710-714页

作者： Xin Wang Yan Wang xiyan zhang Wenyi Yang Jie Yang Department of Child and Adolescent Health Promotion Jiangsu Provincial Center for Disease Control and PreventionNanjing CityJiangsu ProvinceChina

What is already known about this topic?The prevalence of mental health disorders among children and youth in China stands at 17.5%,a figure that has been gradually escalating over recent *** surge has led to substantial psychological distress and financial strain for both families and the wider *** is added by this report?This study boasts an expansive geographical scope by covering the Jiangsu Province extensively and utilizing a substantial sample *** investigation was conducted on the prevalence and risk factors,which included family type and health behaviors,of depressive,anxiety,and stress *** are the implications for public health practice?The mental health status of children and adolescents should be of great concern to the ***,it is important that public health measures are implemented to mitigate the development of depressive *** measures may include regular screening procedures and the implementation of proven interventions.

关键词： measures utilizing Jiangsu

Parenting stress and affective symptoms in parents of autistic children

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Science China(Life Sciences) 2015年第10期58卷 1036-1043页

作者： GONG Yun DU YaSong LI HuiLin zhang xiyan AN Yu WU Bai-Lin Shanghai Mental Health Center Shanghai Jiao Tong University School of Medicine Institutes of Biomedical Sciences Fudan University

We examined parenting stress and mental health status in parents of autistic children and assessed factors associated with such stress. Participants were parents of 188 autistic children diagnosed with DSM-IV criteria and parents of 144 normally developing children. Parents of autistic children reported higher levels of stress, depression, and anxiety than parents of normally developing children. Mothers of autistic children had a higher risk of depression and anxiety than that did parents of normally developing children. Mothers compared to fathers of autistic children were more vulnerable to depression. Age, behavior problems of autistic children, and mothers' anxiety were significantly associated with parenting stress.

关键词： autistic children parenting stress mental health parenting stress index

Preparation and Luminescence Properties of Color-tunable Single-phased LaPO4：Eu3＋/Tb3＋ Phosphors

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Chemical Research in Chinese Universities 2016年第2期32卷 248-252页

作者： DONG Weili zhang xiyan SHI Hui WANG Nengli zhang Wenmin LI Liang XUE Qingxue School of Materials Science and Engineering Changchun University of Science and Technology Changchun 130022 P. R. China

A novel series of color-tunable single-phased phosphors La1-x-yPO4：xEu3＋/yTb3＋（x=0, 0.01, 0.02, 0.03, 0.04, 0.05; y=0, 0.05, 0.10, 0.15, 0.20） was synthesized via microwave-assisted co-precipitation method with diammonium hydrogen phosphate as precipitant. The morphology, crystal structure and photoluminescence properties of the as-prepared samples were characterized by means of X-ray diffraction（XRD）, scanning electron microscopy（SEM） and fluorescence spectrophotometer. The results reveal that the as-synthesized samples calcined at 1100 ℃ display spherical morphology with uniform distribution. Upon excitation with 350 nm ultraviolet radiation, the LaPOa：Eu3＋/Tb3＋ phosphors showed a green light peaking at 543 nm assigned to the characteristic 5Da-7F5 emission of Tb3＋ and a red light peaking at 591 nm corresponding to the characteristic 5D0-7F1 emission of Eu3＋ simultaneously. For the Eu3＋/Tb3＋ co-activated phosphors, Tb3＋ acts as an efficient sensitizer to enhance the emission intensity of Eu3＋ ions. The energy transfer mechanism and the emission color tunability of LaPO4：Eu3＋/Tb3＋ have been studied. The results indicate that a color-tunable luminescence（from green to white to red） can be achieved by adjusting the Eu3＋/Tb3＋ doping ratio in the LaPO4 host matrix.

关键词： Lanthanum phosphate phosphor Photoluminescence property Color-tunable

Cracking Behaviour of Al_2O_3 Short Fibre/Al-5.5Zn Composite in TEM

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Journal of Materials Science & Technology 1997年第3期13卷 235-237页

作者： xiyan zhang Tianxin TAN Wenyi PENG and Qing GAO (Southwest Jiaotong University, Chengdu 610031, China) Southwest Jiaotong University Chengdu 610031 China

The micromechanical behaviour of Al2O3 short fibre reinforced Al-5.5Zn matrix composite has been in-situ studied by using TEM. The results show that in the composite the nucleation and propagation of cracks take place mainly in the matrix, as well as in the region near the fibre/matrix interface. It has been also observed that the microcracks can close during *** the fracture property can be characterized by crack open displacement (COD). The cracking characteristic may result from the large strength difference between the matrix and fibre.

关键词： Cracking Behaviour of Al2O3 Short Fibre/Al-5.5Zn Composite in TEM Al Zn

A Multi-Center Cross-Sectional Study on Visual Impairment and Depression Among Students—Jiangsu Province,China,2017–2022

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China CDC weekly 2023年第51期5卷 1145-1149页

作者： xiyan zhang Wei Du Yan Wang Wenyi Yang Xin Wang Jie Yang Jiangsu Provincial Center for Disease Control and Prevention Nanjing CityJiangsu ProvinceChina School of Public Health Nanjing Medical UniversityNanjing CityJiangsu ProvinceChina School of Public Health Southeast UniversityNanjing CityJiangsu ProvinceChina.

What is already known about this topic?China exhibits a significantly high prevalence ofmyopia compared to other countries globally. Childrenwith vision impairment have been found to engage lessin physical activities, achieve lower academicperformance, and have increased vulnerability *** is added by this report?During a six-year observational study, a populationlevelcorrelation was identified between varying degreesof visual impairment and the presence of depressivesymptoms among students. Specifically, individualswith a visual acuity below 4.0 had a significantly higherodds ratio of 1.90 (95% confidence interval:1.53–2.37) compared to individuals with normal vision(visual acuity ≥5.0).What are the implications for public healthpractice?This study highlights the importance of holistic healthinterventions that address both visual and psychologicalaspects. Understanding common mechanisms andinfluential factors can guide the development of moreimpactful public health strategies.

关键词： globally Visual Jiangsu

Effects of RE^(3+)(RE=La,Ce,Pr,Sm,Dy,Ho,Er,and Tm) on the luminescence of Sr_2MgSiO_5:Eu^(2+) phosphors

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Rare Metals 2011年第1期30卷 14-17页

作者： CHENG Guang WEI Xiaoyan CHENG Liqun LIU Quansheng WANG Xiaochun SUN Haiying zhang xiyan QIU Guanming School of Materials Science and Engineering Changchun University of Science and TechnologyChangchun 130022China

Sr2MgSiO5：Eu^2＋phosphors were synthesized through a high temperature solid state reaction *** phase and luminescence properties of the samples were characterized by X-ray diffraction（XRD） and a luminescence *** effects of RE^3＋（RE = La,Ce,Pr,Sm,Dy,Ho,Er,and Tm） on the luminescent properties of the samples were *** results show that the luminescence spectrum of Sr2MgSiO5：Eu^2＋ is a broad band composed of two emission peaks,at 460 and at 530 nm under near-ultraviolet *** earth ions Re^3＋（RE = La,Ce,Pr,Sm,Dy,Ho,Er,and Tm） have great influence on the emission of Sr2MgSiO5：Eu^2＋ *** La^3＋ ion in Sr2MgSiO5：Eu^2＋ phosphors greatly enhances the emission at 460 and 530 nm.

关键词： phosphors solid state reactions rare earths luminescence