Optimal simulation design for weight reduction of periodic titanium alloy space structures

Liang Xuan,Yanhe Zhang,Siyuan Peng,Yongkang Shen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2

This research investigates the spatial structure of periodic titanium alloys. The response surface optimization method is used to optimize the weight reduction structure of combined model parameters. Under the condition of unidirectional load, the stress and strain results of each model group of a 3D structure with weight reduction rates of 30 %, 50 %, and 70 % are obtained through simulation analysis. Furthermore, the characteristics of the selective laser melting (SLM) forming process are incorporated, and a comparative analysis of the maximum equivalent stress of each group of models under unidirectional load is performed. The optimal structural form and its parameters suitable for multi-directional loads are screened. By using SLM to form the optimal model and carry out a loading test, the ultimate load of the model under different weight reduction rates is obtained to provide a theoretical basis for the next step of 3D printing process research.

Erosion Characteristics of Steep-Slope Colluvial Deposits in Gully under Different Rainfall Intensity and Slope Gradient Conditions, South-East China

Fanshi Jiang,Yanhe Huang,Ming Wang,Jinshi Lin,Gan Zhao,Hongli Ge 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Study on the Cyclic Behavior of an UPPC Beam with an Energy Dissipator and a Conventional UPPC Beam

Xiaoying Wen,Yanhe Li,Jianlei Zhai,Yue Liu 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.9

In this study, low reversed cyclic loading experiments were performed on an Unbonded Partially Prestressed Concrete (UPPC) beam with an energy dissipator and a conventional UPPC beam to investigate the seismic performance of the beams, including displacement restoration, energy dissipation capacity, ductility, and failure patterns. Studies have shown that UPPC beams with energy dissipators are superior to conventional UPPC beams in terms of displacement restoration, energy dissipation capacity, and ductility and are inferior to conventional UPPC beams in terms of failure patterns. The results of this investigation can help us to improve the poor energy dissipation capacity and lack of displacement restoration in UPPC beams. The contact relationship between the unbonded prestressed tendon and the concrete was simulated using the coupling interaction method, The hysteresis curve based on the calculations was close to the hysteresis curve obtained experimentally. The ultimate bearing capacity and ultimate displacement are highly similar.

Seismic Performance Experiment Involving One-Story, Two-Bay Self-control Energy Dissipation UPPC Frames under Low Cyclic Loads

Cheng Qian,Yanhe Li,Dengfeng Xie,Ning Li,Xiaoying Wen 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.7

This paper presents an experimental study of the behavior of three one-story, two-bay unbonded partially prestressed concrete (UPPC) frames, of which two frames are self-control energy dissipation UPPC frames. This study aims to use the self-control energy dissipation UPPC frame as a new frame, and its seismic performance is evaluated compared to that of existing UPPC frames. The new frame utilizes energy dissipation components to provide energy dissipation capabilities, which allow the frame to form a beamhinge mechanism under earthquake actions. The influence of the prestress release percentage on the seismic performance of the UPPC frame is experimentally examined. The test results show that the new UPPC frame displays better ductility and energy dissipation capabilities as the prestress release percentage increases, but the lateral resistance is slightly weaker than that of a common UPPC frame. Overall, the new frame displays better seismic performance than the conventional UPPC frame and can be reused after retrofitting.

Machine Learning-Based Prediction of COVID-19 Severity and Progression to Critical Illness Using CT Imaging and Clinical Data

Purkayastha Subhanik,Xiao Yanhe,Jiao Zhicheng,Thepumnoeysuk Rujapa,Halsey Kasey,Wu Jing,Tran Thi My Linh,Hsieh Ben,Choi Ji Whae,Wang Dongcui,Vallières Martin,Wang Robin,Collins Scott,Feng Xue,Feldman 대한영상의학회 2021 Korean Journal of Radiology Vol.22 No.7

Objective: To develop a machine learning (ML) pipeline based on radiomics to predict Coronavirus Disease 2019 (COVID-19) severity and the future deterioration to critical illness using CT and clinical variables. Materials and Methods: Clinical data were collected from 981 patients from a multi-institutional international cohort with real-time polymerase chain reaction-confirmed COVID-19. Radiomics features were extracted from chest CT of the patients. The data of the cohort were randomly divided into training, validation, and test sets using a 7:1:2 ratio. A ML pipeline consisting of a model to predict severity and time-to-event model to predict progression to critical illness were trained on radiomics features and clinical variables. The receiver operating characteristic area under the curve (ROC-AUC), concordance index (C-index), and time-dependent ROC-AUC were calculated to determine model performance, which was compared with consensus CT severity scores obtained by visual interpretation by radiologists. Results: Among 981 patients with confirmed COVID-19, 274 patients developed critical illness. Radiomics features and clinical variables resulted in the best performance for the prediction of disease severity with a highest test ROC-AUC of 0.76 compared with 0.70 (0.76 vs. 0.70, p = 0.023) for visual CT severity score and clinical variables. The progression prediction model achieved a test C-index of 0.868 when it was based on the combination of CT radiomics and clinical variables compared with 0.767 when based on CT radiomics features alone (p < 0.001), 0.847 when based on clinical variables alone (p = 0.110), and 0.860 when based on the combination of visual CT severity scores and clinical variables (p = 0.549). Furthermore, the model based on the combination of CT radiomics and clinical variables achieved time-dependent ROC-AUCs of 0.897, 0.933, and 0.927 for the prediction of progression risks at 3, 5 and 7 days, respectively. Conclusion: CT radiomics features combined with clinical variables were predictive of COVID-19 severity and progression to critical illness with fairly high accuracy.

중국 반부패운동의 곤경과 새로운 전략에 대한 연구

Dong Qiang,Song Yanhe,Rui Donggen 한국부패학회 2015 한국부패학회보 Vol.20 No.2

시진핑정권 출범 후, 중국의 반부패운동은 18기 공산당중앙회를 거쳐 더 강화되고 있다. 많은 연구자들은 중국의 반부패운동이 일시적일 수도 있으며, 정권을 공고화하기 위한 수단으로 보여주기 정책이라고 하였다. 하지만 본 논문은 중국의 반부패운동이 한번의 일시적인 이벤트에 거치는 것이 아니라 시진핑정권 전반에 걸쳐 장기적인 통치수단으로 작용할 것으로 보고 있다. 본 논문에서 구체적으로 18기 중국공산당회의 이후 “호랑이”와 “파리”를 모두 잡는 반부패운동의 특징을 보여 주려고 구체적인 사건과 반부패의 ‘전형적 인물’들을 중심으로 반부패의 특징과 성격을 밝혀내고자 하였으며, 반부패운동이 지속될 것이라는 추이를 내놓았다. Since the 18th CPC National Congress, Chinese Communist Party Central Committee has been improving the Party’s style of work and strengthening the building of a clean government while a campaign in order to combat corruption is being carried out firmly, strongly and boldly to severely punish corruption , fighting both “tigers” and “flies” perseveringly, which reveals the confidence and determination of CPC to combat corruption and build a clean government. In this article, based on how to view the corruption in China under the new situation, the current corruption is analyzed objectively, furthermore, the current moves, achievements and features in combating corruption are taken apart profoundly, the coming difficulties of China in combating corruption are faced straightly, in the end, the routing of combating corruption and building a clean government in the future of China is thought rationally and penetratingly.

Modeling and Control of a Magnus-effect-based Ducted Fan Aerial Vehicle

Qingming Hou,Hongzhe Jin,Yanhe Zhu,Yongsheng Gao,Jie Zhao 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.4

A ducted fan aerial vehicle model using Magnus effect steering engine is proposed in this paper. This model utilizes a steering engine that comprises four cylinders that are symmetrically installed at the aft inside the duct. Interaction between the spinning cylinder surface and the duct jet flow causes the aerodynamic lift proportional to angular velocity of the cylinder. Therefore, operating range of the aerodynamic lift is guaranteed to be sufficiently wide. The efficiency of the proposed method is confirmed via numerical simulations on integrated flight dynamics developed in this study.

Design and evaluation of a 7-DOF cable-driven upper limb exoskeleton

Feiyun Xiao,Yongsheng Gao,Yong Wang,Yanhe Zhu,Jie Zhao 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.2

This paper presents a seven degrees of freedom cable-driven upper limb exoskeleton (CABXLexo-7), which is compact, lightweight, and comfortable for post-stroke patients. To achieve the compactness of exoskeleton, two types of cable-driven differential mechanisms were designed. The cable-conduit mechanisms were applied to transmit the power of motors mounted on the backboard to the corresponding joints, then the whole weight of the exoskeleton could be light to ensure a comfortable motion assistance. In the course of experiments, the surface electromyography signals of major muscles related with the movements of upper limb were collected to evaluate the assistant ability of exoskeleton. The experimental results showed that the activation levels of corresponding muscles were reduced by using the seven degrees of freedom cable-driven upper limb exoskeleton in the course of rehabilitation, and it demonstrated that the exoskeleton can provide effective movements assistance to the post-stroke patients.

Highly stable palladium-loaded TiO2 nanotube array electrode for the electrocatalytic hydrodehalogenation of polychlorinated biphenyls

Chunyue Cui,Juan Wu,Yanjun Xin,Yanhe Han 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.6

Palladized TiO2 nanotube array electrode was prepared for the electrocatalytic hydrodehalogenation (HDH) of 2,4,5-trichlorobiphenyl (2,4,5-PCB). The TiO2 nanotube array electrode was successfully fabricated by anodic oxidation method, and Pd was loaded onto the TiO2 nanotubes by electrochemical deposition. The morphology and structure of the nanotube array electrodes with and without Pd catalysts were evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results showed that the diameters and lengths of the TiO2 nanotubes were 30-50 nm and 200-400 nm, respectively. The particle size of the Pd was about 12 nm. Electrocatalytic HDH of 2,4,5-PCB with the Pd/TiO2 nanotube array electrode was performed in H-cell reactor. Under a constant potential of −1.0 V, the HDH efficiency of 2,4,5-PCB was 90% and the biphenyl yield was 83% (15% current efficiency) within 180min at the Pd/TiO2 nanotube array electrode. Compared with the Pd/Ti electrode, the Pd/TiO2 nanotube array electrode exhibited higher HDH efficiency and stability. Additionally, the effect of the primary HDH factors was also investigated.

Bartonella rochalimae, B. grahamii, B. elizabethae, and Wolbachia spp. in Fleas from Wild Rodents near the China-Kazakhstan Border

Xiaoping Yin,Shanshan Zhao,Bin Yan,Yanhe Tian,Teer Ba,Jiangguo Zhang,Yuanzhi Wang 대한기생충학ㆍ열대의학회 2019 The Korean Journal of Parasitology Vol.57 No.5

The Alataw Pass, near the Ebinur Lake Wetland (northwest of China) and Taldykorgan (east of Kazakhstan), is a natural habitat for wild rodents. To date, little has been done on the surveillance of Bartonella spp. and Wolbachia spp. from fleas in the region. Here we molecularly detected Bartonella spp. and Wolbachia spp. in wild rodent fleas during January and October of 2016 along the Alataw Pass-Kazakhstan border. A total of 1,706 fleas belonging to 10 species were collected from 6 rodent species. Among the 10 flea species, 4 were found to be positive for Wolbachia, and 5 flea species were positive for Bartonella. Molecular analysis indicated that i) B. rochalimae was firstly identified in Xenopsylla gerbilli minax and X. conforms conforms, ii) B. grahamii was firstly identified in X. gerbilli minax, and iii) B. elizabethae was firstly detected in Coptopsylla lamellifer ardua, Paradoxopsyllus repandus, and Nosopsyllus laeviceps laeviceps. Additionally, 3 Wolbachia endosymbionts were firstly found in X. gerbilli minax, X. conforms conforms, P. repandus, and N. laeviceps laeviceps. BLASTn analysis indicated 3 Bartonella species showed genotypic variation. Phylogenetic analysis revealed 3 Wolbachia endosymbionts were clustered into the non-Siphonaptera Wolbachia group. These findings extend our knowledge of the geographical distribution and carriers of B. rochalimae, B. grahamii, B. elizabethae, and Wolbachia spp. In the future, there is a need for China-Kazakhstan cooperation to strengthen the surveillance of flea-borne pathogens in wildlife.