Construction of High Strain Rate Loading Constitutive Model and Failure Model and Prediction of Forming Limit for LA103Z Magnesium Alloy

Hailiang Yang,Xiao Wang,Peng Ni,Zhewen Li,Huixia Liu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

In order to use numerical simulation to reveal the formability of magnesium–lithium alloys and other light alloys under highstrain rate, it is crucial to construct a constitutive model and a forming limit diagram (FLD) of LA103Z alloy that was formedby laser shock at high strain rate. In this study, three different uniaxial tensile experiments on the ultralight alloy materialLA103Z magnesium alloy were conducted, the mechanical behavior of the material with sensitivity to high strain rate wasstudied, and a Johnson–Cook (JC) constitutive model sensitive to high strain rates and suitable for laser shock forming wasproposed. At the same time, the constitutive parameters and failure parameters of the modified JC model of LA103Z magnesiumalloy were obtained through three different uniaxial tensile experiments. On the basis of the relationship betweentensile loading and stress–strain of LA103Z magnesium alloy, the experiments demonstrated the precision of the modified JCconstitutive model. A modified constitutive model was then developed by using the user material subroutine VUMAT, andthen it was applied to ABAQUS. Finally, the formability of the material was simulated, and the FLD of LA103Z magnesiumalloy material in laser shock forming was predicted. This study provides guidance on the actual production and applicationof LA103Z magnesium alloys.

Influence of Microstructure and Mechanical Properties on Formability in High Strain Rate Rolled AZ31 Magnesium Alloy Sheets

Fubao Liu,Xiao Liu,Biwu Zhu,Hui Yang,Gang Xiao,Mingyue Hu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

High strain-rate rolling (≥ 10 s−1) has been successfully employed to produce AZ31 magnesium alloy sheets to a high reductionof 82% with a fine grain structure in a single pass. The rolled sheets inevitably undertake various forming processessuch as press and deep forming in the fabrication stage. To investigate the formability, the Erichsen tests were carried out onhigh strain rate rolled AZ31 magnesium alloy sheets at room temperature. The relationship among mechanical properties,microstructure and formability were investigated. The crack behavior during Erichsen tests was also studied. It was foundthat the formability was related to the lowest in-plane tensile strengthen and dislocation density of initial microstructure. The competitive relationship between micro-crack and twinning/shear bands would also influence the formability of highstrain rate rolled magnesium alloy sheets. Deformed shear band with substaintial twins prohibits the crack extension andenhances strengthen of materials in front of crack tip.

The Event Detection of Serving a Ball in Sports Video

Jingmeng Sun,Yang Liu,Gang Liu1,Yang Wang,Haitao Yang 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.3

Tennis video’s serve events were detected. In other words, athletes area were obtained to calculate particle of athletes area and particle shift in adjacent frame by using background subtraction algorithm. And then tennis video’s serve events were inferred, according to specific constraints on serve, through establishing ontology and setting SWRL rules.

자동차용 센서응용을 위한 CMOS 열전대 공정 개발

이광만,박세광,도양회,Liu, C.C. 경북대학교 센서기술연구소 1996 연차보고서 Vol.1996 No.-

자동차용 센서응용을 위하여 CMOS공정을 이용한 마이크로 열센서의 기초 제조공정을 개발하고 CMOS공정과 호환성을 갖는 열센서의 마스크 설계와 공정 설계를 하였다. LPCVD법, APCVD법 및 실리콘 미세가공기술을 각각 활용하여 열전도율이 낮고 내부응력이 최소화된 NON절연막 다이아프램을 형성하였다. TMAH용액의 농도와 온도를 3∼25wt%와 80∼90℃ 범위내에서 각각 변화시키면서 실리콘의 식각특성을 조사하였다. 그리고 NON절연막의 기계적 및 열적응력을 NON 캔티레버와 빔의 조합으로 이루어진 시험패턴의 식각을 통하여 각각 조사하였다. 그리고 CMOS 구동회로를 내장한 마이크로 열센서의 기초연구를 하였다. A basic fabrication process of micro thermal sensor was developed and the related mask pattern and process were designed by standard CMOS process for the automotive sensor application. An NON dielectric diaphragm with low thermal conductivity and minimum internal stress was fabricated by LPCVD, APCVD methods and silicon micromachining techniques. Etching characteristics of silicon in the TMAH solution was studied with the TMAH concentration and temperature variation of 3∼25wt% and 80∼90℃, respectively. Mechanical and thermal stress of the NON layer were investigated by using a test pattern which composed of cantilever and beam. And a micro thermal sensor with on-chip CMOS driving circuits was studied.

Hypoxia Mediates Runt-Related Transcription Factor 2 Expression via Induction of Vascular Endothelial Growth Factor in Periodontal Ligament Stem Cells

Manjing Deng,Qian Xu,Zhihua Liu1,Ling Guo,Rui Liu,Rulei Li,Xiang Chu,Jiajia Yang,Jia Luo,Faming Chen 한국분자세포생물학회 2019 Molecules and cells Vol.42 No.11

Periodontitis is characterized by the loss of periodontal tissues, especially alveolar bone. Common therapies cannot satisfactorily recover lost alveolar bone. Periodontal ligament stem cells (PDLSCs) possess the capacity of self-renewal and multilineage differentiation and are likely to recover lost alveolar bone. In addition, periodontitis is accompanied by hypoxia, and hypoxia-inducible factor-1α (HIF-1α) is a master transcription factor in the response to hypoxia. Thus, we aimed to ascertain how hypoxia affects runt-related transcription factor 2 (RUNX2), a key osteogenic marker, in the osteogenesis of PDLSCs. In this study, we found that hypoxia enhanced the protein expression of HIF-1α, vascular endothelial growth factor (VEGF), and RUNX2 ex vivo and in situ. VEGF is a target gene of HIF-1α, and the increased expression of VEGF and RUNX2 proteins was enhanced by cobalt chloride (CoCl2, 100 μmol/L), an agonist of HIF-1α, and suppressed by 3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole (YC-1, 10 μmol/L), an antagonist of HIF-1α. In addition, VEGF could regulate the expression of RUNX2, as RUNX2 expression was enhanced by human VEGF (hVEGF165) and suppressed by VEGF siRNA. In addition, knocking down VEGF could decrease the expression of osteogenesis-related genes, i.e., RUNX2, alkaline phosphatase (ALP), and type I collagen (COL1), and hypoxia could enhance the expression of ALP, COL1, and osteocalcin (OCN) in the early stage of osteogenesis of PDLSCs. Taken together, our results showed that hypoxia could mediate the expression of RUNX2 in PDLSCs via HIF-1α-induced VEGF and play a positive role in the early stage of osteogenesis of PDLSCs

Fenofibrate Increases Radiosensitivity in Head and Neck Squamous Cell Carcinoma via Inducing G2/M Arrest and Apoptosis

Liu, Jia,Ge, Yang-Yang,Zhu, Hong-Cheng,Yang, Xi,Cai, Jing,Zhang, Chi,Lu, Jing,Zhan, Liang-Liang,Qin, Qin,Yang, Yan,Yang, Yue-Hua,Zhang, Hao,Chen, Xiao-Chen,Liu, Zhe-Ming,Ma, Jian-Xin,Cheng, Hong-Yan,S Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.16

Radiation therapy is an important treatment for head and neck squamous cell carcinoma (HNSCC). However, how to promote radiation sensitivity in HNSCC remains a challenge. This study aimed to investigate the radiosensitizing effects of fenofibrate on HNSCC and explore the underlying mechanisms. HNSCC cell lines CNE-2 and KB were subjected to ionizing radiation (IR), in the presence or absence of fenofibrate treatment. Cell growth and survival, apoptosis and cell cycle were evaluated. In addition, CNE-2 cells were xenografted into nude mice and subjected to IR and/or fenofibrate treatment. The expression of cyclinB and CDK1 was detected by Western blotting. Our results showed that fenofibrate efficiently radiosensitized HNSCC cells and xenografts in mice, and induced apoptosis and G2/M arrest via reducing the activity of the CDK1/cyclinB1 kinase complex. These data suggest that fenofibrate could be a promising radiosensitizer for HNSCC radiotherapy.

The Clinical Observation of Inflammation Theory for Depression: The Initiative of the Formosa Long COVID Multicenter Study (FOCuS)

Shu-Tsen Liu(Shu-Tsen Liu),Sheng-Che Lin(Sheng-Che Lin),Jane Pei-Chen Chang(Jane Pei-Chen Chang),Kai-Jie Yang(Kai-Jie Yang),Che-Sheng Chu(Che-Sheng Chu),Chia-Chun Yang(Chia-Chun Yang),Chih-Sung Liang( 대한정신약물학회 2023 CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE Vol.21 No.1

There is growing evidence that the coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with increased risks of psychiatric sequelae. Depression, anxiety, cognitive impairments, sleep disturbance, and fatigue during and after the acute phase of COVID-19 are prevalent, long-lasting, and exerting negative consequences on well-being and imposing a huge burden on healthcare systems and society. This current review presented timely updates of clinical research findings, particularly focusing on the pathogenetic mechanisms underlying the neuropsychiatric sequelae, and identified potential key targets for developing effective treatment strategies for long COVID. In addition, we introduced the Formosa Long COVID Multicenter Study (FOCuS), which aims to apply the inflammation theory to the pathogenesis and the psychosocial and nutrition treatments of post-COVID depression and anxiety.

Fabrication of carbon nanotube-loaded TiO2@AgI and its excellent performance in visible-light photocatalysis

Liu Yang,Yang An,Bin Dai,Xuhong Guo,Zhiyong Liu,Banghua Peng 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.2

Novel, visible light driven CNTs-TiO2@AgI hybrid materials were synthesized by a simple solvothermaldissolution- precipitation method, during which the acid vapor treated carbon nanotubes (CNTs) as template, AgI as sensitizer and TiO2 as the bridge unified them to form a ternary composite. The morphology and chemical components of as-prepared samples were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). XRD and XPS characterizations indicated that anatase TiO2 and crystal AgI co-existed in the composite. HRTEM demonstrated CNTs were decorated with well-dispersed AgI and TiO2 nanoparticles (NPs), and TiO2 had an intimate connection with both AgI and CNTs. Diffusive reflectance UV-vis spectroscopy of CNTs-TiO2@AgI nanocomposite was extended to the whole UV-visible region due to adding of CNTs and AgI NPs. Degradation of Rhodamine B (RhB) polluted water using CNTs-TiO2@AgI NPs was carried out under visible light irradiation, and it showed higher degradation efficiency than CNTs-TiO2, TiO2@AgI, and CNTs@AgI NPs. The primary reason for the enhanced photocatalytic property was attributed to the synergic effect in CNTs-TiO2@AgI, which included the good adsorption ability and electrical conductivity of CNTs as well as the intimate connection and hetero-junctions among AgI, TiO2, and CNTs. Meanwhile, the as-prepared hybrid materials can be easily separated and reclaimed from the liquid phase, and the recycling tests indicated CNTs-TiO2@AgI had renewable performance.

Children‘s Omoiyari, "Empathic Consideration": Through Interviews with Japanese and Chinese Children of Four and Five Year Old

Yang Yang Liu,Yoko Shirakawa 한국유아교육학회 2003 INTERNATIONAL JOURNAL OF EARLY CHILDHOOD EDUCATION Vol.9 No.1

To examine children‘s Omoiyari. empathic consideration, the author interviewed sixty Japanese children age four and five and sixty Chinese children of the same age , using picture-story cards of six Omoiyari Situations. Children were first asked whether they would act with empathic consideration or not, and then the reason for the answer. Both Japanese children and Chinese children showed empathic consideratior in all six situations except Situation 5, the empathic consideration to the farmer who grew rice for children. Both Japanese children and Chinese children showed empathic consideration when they understood the situation correctly. Children‘s empathic consideration was closely related to the children‘s needs or wishes in each situation. The stronger their wishes were ,the less frequently they showed empathic consideration. Some children, however, could resolve conflicts between their own needs and the other people‘s needs, and showed empathic consideration by sharing, waiting ,looking for alternatives, forgiving negotiating and so on. The Japanese children frequently used reasoning based on considering the other person‘s feelings such as ‘because I feel sorry with the African child‘, more frequently than the Chinese children, Chinese children showed empathic consideration to a strange blind man and the farmer who grows rice more frequently than Japanese children, whereas they showed empathic consideration less frequently to a father as a familiar person and to peers than to Japanese children. Chinese children often mentioned reasons based on indoctrination by adults. Cultural differences were reflected on children‘s empathic consideration in both countries.

Massive open online course's teaching reform path of integrating ideological and political elements into the general education course of corporate crime investigation

Liu Aijiao(Aijiao Liu),Shi Jiangshan(Jiangshan Shi),Yang Renqiao(Renqiao Yang) 아시아사회과학학회 2023 Jornal of Asia Social Science Vol.10 No.2

The investigation of corporate crimes is a key course in public security colleges, which has high application, sociality, practicality and theory. With the rapid development of modern information technology, “Internet + education” has become the main direction of undergraduate teaching reform. It is extremely important to combine massive open online course with the teaching of corporate crime investigation. On the premise of expanding college students' professional knowledge and subject knowledge, general education can shape students' thinking paradigm in line with socialist core values and ensure students to develop scientific three views. Taking the general course “Investigation of Corporate Crime Cases” in public security colleges as an example, this paper discusses the necessity, problems and relevant countermeasures of integrating ideological and political elements into the online teaching of general education courses, and provides reference for the design and practice of ideological and political courses in the online teaching of general education courses.