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Changhao Wang,Yu Luo,Jinru Luo,Xiao Song,Wei Zhang,Pinghuai Wang,Zhenghao Liu,Maoyin Wang,Xinghui He,Linjiang Chai 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.4
Titanium alloys are one of the most important structural materials for the aerospace applications, which bring active studyon microstructural and mechanical optimization of the alloys. In the present study, commercial TA2 titanium sheets withdifferent initial textures were rolled to a strain of 4% at liquid nitrogen temperature. Microstructures of the rolled sheets werecharacterized using a scanning electron microscope equipped with an EBSD detector and their mechanical properties weretested through quasi-static uniaxial tension tests at room temperature. The influence of the initial texture on the microstructureand mechanical performance of the cryorolled sheet were discussed. Twinning is found to occur in the TA2 sheets after rollingeven at a small strain. Initial texture is an important factor affecting both numbers and types of the twins. {11–22} contractiontwinning is always the dominating type of twins for all three sheets having different initial textures. A lot of {11–22}and {11–24} twins can be found in the sheets with the initial texture of C-axes//ND, while the sheet with an initial texture ofC-axes away from the ND contains few twins, with a high density of dislocations developed instead. Along with contractiontwinning, many {10–12} and {11–21} twins are detected in the sheet with the initial texture of C-axes⊥ND. The cryorolledsheet having the densest twins shows the best mechanical properties, indicating a beneficial effect of a small pre-strain.
Active Patchy Colloids with Shape-Tunable Dynamics
Wang, Zuochen,Wang, Zhisheng,Li, Jiahui,Cheung, Simon Tsz Hang,Tian, Changhao,Kim, Shin-Hyun,Yi, Gi-Ra,Ducrot, Etienne,Wang, Yufeng American Chemical Society 2019 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.141 No.37
<P>Controlling the complex dynamics of active colloids-the autonomous locomotion of colloidal particles and their spontaneous assembly-is challenging yet crucial for creating functional, out-of-equilibrium colloidal systems potentially useful for nano- and micromachines. Herein, by introducing the synthesis of active “patchy” colloids of various low-symmetry shapes, we demonstrate that the dynamics of such systems can be precisely tuned. The low-symmetry patchy colloids are made in bulk via a cluster-encapsulation-dewetting method. They carry essential information encoded in their shapes (particle geometry, number, size, and configurations of surface patches, etc.) that programs their locomotive and assembling behaviors. Under AC electric field, we show that the velocity of particle propulsion and the ability to brake and steer can be modulated by having two asymmetrical patches with various bending angles. The assembly of monopatch particles leads to the formation of dynamic and reconfigurable structures such as spinners and “cooperative swimmers” depending on the particle’s aspect ratios. A particle with two patches of different sizes allows for “directional bonding”, a concept popular in static assemblies but rare in dynamic ones. With the capability to make tunable and complex shapes, we anticipate the discovery of a diverse range of new dynamics and structures when other external stimuli (e.g., magnetic, optical, chemical, etc.) are employed and spark synergy with shapes.</P> [FIG OMISSION]</BR>
Research on the Seismic Design of High-rise Steel Building Based on Security Perspective
Changhao Zhang,Jianhu Feng,Xuntao Wang 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.5
In recent years, with the continuous development of the construction industry, the development of high-rise steel structure growth fast in China. At the same time, it is very important to analyze the structure of these high-rise steel Building, especially the seismic performance analysis. In this paper, the authors analyze the seismic performance of high rise buildings by using finite element modeling, dynamic and static analysis. Through the static analysis of steel structure that combined with dead load, live load and wind load, the result shows that when steel support under the force, the maximum node stress mainly appears in the low-end and the ninth layer, which is located in 19, 22 axis node stress is the largest, respectively as 65.9Mpa, 62.6Mpa, it is safety and within the strength limit. The results can provide a theoretical basis for the seismic design of steel structure buildings
Changhao Zhang,Wei Wang,Jianhu Feng 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.10
According to the mechanical performance and energy dissipation characteristics of buckling restrained brace, combined with the seismic design idea of code for seismic design of buildings(GB 50011 -2010), we put forward the displacement-based design method for structures with buckling restrained brace. In this paper, we analyze the seismic design of high-rise buildings and test the relationship between structural target displacement and BRB added stiffness for a single-degree-reedom system. By using an engineering example to verify the validity of the design method, the time history analysis results to elastic and elastic-plastic show that the displacement of BRB frame structure under frequent earthquake can reach the expected target displacement, under rare earthquake, the input energy are dissipated by BRB, improving the seismic capacity and safety reserves.
False diffusion in numerical simulation of combustion processes in tangential-fired furnace
Xuchang Xu,Zhigang Wang,Yuqun Zhuo,Changhao Zheng 대한기계학회 2007 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.21 No.11
Numerical simulation serves as one of the most important tools for analyzing coal combustion in Tangentially Fired Furnaces (TFF) with NUMERICAL FALSE DIFFUSION as one key problem that degrades the simulation accuracy, especially for complex flow patterns. False diffusion often completely compromises the accuracy, leading to erroneous predictions. This paper reviews various methods to reduce the numerical diffusion. In computational fluid dynamics (CFD), false diffusion originates from a truncation error of the Taylor series approximation of the derivative and multidimensional discretization effects. Higher-order upwind convective schemes were designed to reduce truncation errors, while grid line adjusting methods were developed to reduce crossflow diffusion. This paper compares numerical and experimental results for isothermal flows to evaluate these methods. Results with the standard upwind scheme in a rectangular Cartesian mesh are compared with results in body-fitted meshes for comprehensive combustion processes in a TFF. Analysis of the false diffusion effect in the x, y, z directions and the artificial viscosity distribution in a rectangular mesh shows where the false diffusion overtakes the real physical diffusion and where the mesh must be refined or grid line must be adjusted to improve TFF combustion simulations.
Yudong Shi,Wei Li,Changhao Chen,Xiaoping Yuan,Yingying Yang,Song Wang,Zhiwei Liu,Feng Geng,Jiawei Wang,Xiangfen Luo,Xiangwang Wen,Lei Xia,Huanzhong Liu 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.11
Objective Excessive daytime sleepiness (EDS) and insomnia symptoms are common in patients with major depressive disorder (MDD), which might lead to a poor prognosis and an increased risk of depression relapse. The current study aimed to investigate the prevalence, and sociodemographic and clinical correlates of EDS and insomnia symptoms among adolescents with MDD.Methods The sample of this cross-sectional study included 297 adolescents (mean age=15.26 years; range=12–18 years; 218 females) with MDD recruited from three general and four psychiatric hospitals in five cities (Hefei, Bengbu, Fuyang, Suzhou, and Ma’anshan) in Anhui Province, China between January and August, 2021. EDS and insomnia symptoms, and clinical severity of depressive symptoms were assessed using Epworth sleepiness scale, Insomnia Severity Index, and Clinical Global Impression-Severity.Results The prevalence of EDS and insomnia symptoms in adolescents with MDD was 39.7% and 38.0%, respectively. Binary logistic regression analyses showed that EDS symptoms were significantly associated with higher body mass index (odds ratio [OR]=1.097, 95% confidence interval [CI]=1.027–1.172), more severe depressive symptoms (OR=1.313, 95% CI=1.028–1.679), and selective serotonin reuptake inhibitors use (OR=2.078, 95% CI=1.199–3.601). And insomnia symptoms were positively associated with female sex (OR=1.955, 95% CI=1.052–3.633), suicide attempts (OR=1.765, 95% CI=1.037–3.005), more severe depressive symptoms (OR=2.031, 95% CI=1.523–2.709), and negatively associated with antipsychotics use (OR=0.433, 95% CI=0.196–0.952).Conclusion EDS and insomnia symptoms are common among adolescents with MDD. Considering their negative effects on the clinical prognosis, regular screening and clinical managements should be developed for this patient population.
Ergonomic Development and Evaluation of UI Design for Optical Brain- Machine Interface (OBMI) System
Xin Cui(최신아),Hayoung Jung(정하영),Halim Kim(김하림),Yang Xiaopeng(양샤오펑),Linqing Feng(펭린칭),Shaomin Zhang(장샤오민),Mingkang Li(리밍캉),Changhao Liu(리우창하오),Jiawei Han(한지아웨이),Ruixue Wang(왕루이수에),Heecheon You(유희천) 대한인간공학회 2020 대한인간공학회 학술대회논문집 Vol.2020 No.10