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Microstructural characteristics and low-cycle fatigue properties of AZ91 and AZ91-Ca-Y alloys extruded at different temperatures

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Journal of Magnesium and Alloys 2023年第3期11卷 892-902页

作者： Ye Jin Kim Young Min Kim jun Ho bae Soo-hyun Joo Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Republic of Korea Advanced Metals Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea Department of Materials Science and Engineering Dankook UniversityCheonan 31116Republic of Korea

The commercial AZ91 alloy and nonflammable SEN9(AZ91-0.3Ca-0.2Y,wt%)alloy are extruded at 300°C and 400°*** microstructure,tensile and compressive properties,and low-cycle fatigue(LCF)properties are investigated,with particular focus on the influence of the extrusion *** the AZ91 and SEN9 materials extruded at 300°C(300-materials),numerous fine Mg_(17)Al_(12)particles are inhomogeneously distributed owing to localized dynamic precipitation during extrusion,unlike those extruded at 400°C(400-materials).These fine particles suppress the coarsening of recrystallized grains,decreasing the average grain size of *** the four extruded materials have considerably different microstructures,the difference in their tensile yield strengths is insignificant because strong grain-boundary hardening and precipitation hardening effects in 300-materials are offset almost completely by a strong texture hardening effect in ***,owing to their finer grains and weaker texture,300-materials have higher compressive yield strengths *** the LCF tests,{10-12}twinning is activated at lower stresses in 400-materials than in *** the fatigue damage accumulated per cycle is smaller in 400-materials,they have longer fatigue lives than those of 300-materials.A fatigue life prediction model for the investigated materials is established on the basis of the relationship between the total strain energy density(ΔW_(t))and the number of cycles to fatigue failure(N_(f)),and it is expressed through a simple equation(ΔW_(t)=10·N_(f)-0.59).This model enables fatigue life prediction of both the investigated alloys regardless of the extrusion temperature and strain amplitude.

关键词： AZ91-Ca-Y Extrusion temperature Microstructure Low-cycle fatigue Fatigue life prediction model

Adaptive Consistent Management to Prevent System Collapse on Shared Object Manipulation in Mixed Reality

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Computers, Materials & Continua 2023年第4期75卷 2025-2042页

作者： jun Lee hyun Kwon Department of Game Software Hoseo UniversityAsan-siKorea Department of Artificial Intelligence and Data Science Korea Military AcademySeoulKorea

A concurrency control mechanism for collaborative work is akey element in a mixed reality environment. However, conventional lockingmechanisms restrict potential tasks or the support of non-owners, thusincreasing the working time because of waiting to avoid conflicts. Herein, wepropose an adaptive concurrency control approach that can reduce conflictsand work time. We classify shared object manipulation in mixed reality intodetailed goals and tasks. Then, we model the relationships among goal,task, and ownership. As the collaborative work progresses, the proposedsystem adapts the different concurrency control mechanisms of shared objectmanipulation according to the modeling of goal–task–ownership. With theproposed concurrency control scheme, users can hold shared objects andmove and rotate together in a mixed reality environment similar to realindustrial sites. Additionally, this system provides MS Hololens and Myosensors to recognize inputs from a user and provides results in a mixed realityenvironment. The proposed method is applied to install an air conditioneras a case study. Experimental results and user studies show that, comparedwith the conventional approach, the proposed method reduced the number ofconflicts, waiting time, and total working time.

关键词： Mixed reality upper body motion recognition shared object manipulation adaptive task concurrency control

Polymer-based membranes for solvent-resistant nanofiltration:A review

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Chinese Journal of Chemical Engineering 2017年第11期25卷 1653-1675页

作者： Slow Kee Lira Kunli Goh Tae-hyun bae Rong Wang Singapore Membrane Technology Center Nanyang Environment and WaterResearch InstituteNanyang Technological UniversityI Cleantech Loop637141 SingaporeSingapore Nanyang Environment and Water Research Institute Interdisciplinary Graduate SchoolNanyang Technological University637141 SingaporeSingapore School of Chemical and Biomedical Engineenng Nanyang Technological University62 Nanyang Drive637459 SingaporeSingapore School of Civil and Environmental Engineering Nanyang Technological University50 NanyangAvenue639798 SingaporeSingapore

Separation of organic mixture is an inevitable process in most modern industrial processes. In the quest for a more sustainable and efficient separation, solvent-resistant nanofiltration(SRNF) has emerged as a promising answer. This is because SRNF is a membrane-based process which offers the key advantages of high efficacy and low energy intensity separation. In particular, polymer-based membranes can offer compelling opportunities for SRNF with unprecedented cost-effectiveness. As a result, intensive research efforts have been devoted into developing novel polymer-based membranes with solvent-resistant capacities as well as exploring potential applications in different types of industries. In this review, we aim to give an overview of the recent progress in the development of the state-of-the-art polymer-based membranes for SRNF in the first section. Emerging nanomaterials for mixed matrix and thin film nanocomposite membranes are also covered in this section. This is followed by a discussion on the current status of membrane engineering and SRNF membrane commercialization. In the third section, we highlight recent efforts in adopting SRNF for relevant industrial applications such as food, bio-refinery, petrochemical, fine chemical and pharmaceutical industries followed by separations of enantiomers in stereochemistry, homogeneous catalysis and ionic liquids. Finally, we offer a perspective and provide deeper insights to help shape future research direction in this very important field of SRNF.

关键词： Nanofiltration Solvent-resistant Polymeric membranes Nanomaterials Crosslinking Industrial applications

Recent progress in quasi-two-dimensional and quantum dot perovskite light-emitting diodes harnessing the diverse effects of ligands:A review

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Nano Research 2022年第7期15卷 6449-6465页

作者： Yurim bae jun Ryu Saemon Yoon Dong-Won Kang School of Energy Systems Engineering Chung-Ang UniversitySeoul 06974Republic of Korea Department of Smart City Chung-Ang UniversitySeoul 06974Republic of Korea

Halide perovskites have been extensively studied for use as light-emitting diodes(LEDs)in next-generation displays due to their beneficial characteristics,including their high color purity and wide color *** perovskites can be categorized into four representative structures:three-dimensional(3D)bulk,two-dimensional(2D),quasi-two-dimensional(quasi-2D),and quantum dot(QD).Recently,excellent advances in the performance of perovskite LEDs(PeLEDs),especially those with quasi-2D and QD architectures,have been demonstrated with the incorporation of organic chain *** can both modify the structure of PeLEDs,such as forming multi-quantum wells in quasi-2D PeLEDs and essential passivation layers in QD PeLEDs,and also enhance their optical *** appropriate use of ligands in PeLEDs can thus lead to greater luminescence,current efficiency,power efficiency,and external quantum *** this review,the principal roles of ligands in quasi-2D and QD PeLEDs are systematically ***,current limitations and future perspectives are discussed in detail.

关键词： perovskites light emitting diode ligands quasi-two-dimensional(quasi-2D) quantum dot

Aging Behavior of Mg-Y-Zr and Mg-Nd-Zr Cast Alloys

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Journal of Materials Science & Technology 2008年第1期24卷 80-84页

作者： Yang-Do Kim Nam-hyun Kang Il-Guk Jo Kyung-hyun Kim In-bae Kim School of Materials Science and Engineering Pusan National University 30 Jangjun-dongGeumjeong-guBusan 609-735Korea Deptartment of Materials Engineering Korea Institute of Machinery & Materials 66 Sangnam-dongChangwonGyeongsangnam-do 641-010Korea

Aging behavior of Mg-3.6Y-0.5Zr and ***-0.5Zr alloys was investigated by microhardness measurement and transmission electron *** the case of Mg-Y-Zr alloy,the presence ofβ″phase,a major strength- ener,having base centered orthorhombic structure with its lattice constants of a-（β″）=0.64 nm,b-（β″）=2.22 nm, and c-（β″）=0.52 nm was *** the case of Mg-Nd-Zr alloy aged at 250℃,the presence ofβ″andβ′phases was *** crystal structure ofβ″phase was found to be DO-（19） and its orientation relationships with Mg matrix were [0001]-（β″）//[0001]-（Mg） and [01（？）0]-（β″）//[01（？）0]-（Mg）.Theβ′phase had face centered cubic structure and its orientation relationships with Mg matrix were [011]-（β′）//[0001]-（Mg） and [（？）1（？）]β′//[（？）110]）-（Mg）. The ***-0.5Zr alloy showed higher hardness compared with Mg-3.6Y-0.5Zr alloy.

关键词： Mg-Y-Zr alloy Mg-Nd-Zr alloy Precipitation sequence

Spatial Multi-Presence System to Increase Security Awareness for Remote Collaboration in an Extended Reality Environment

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Intelligent Automation & Soft Computing 2023年第7期37卷 369-384页

作者： jun Lee hyun Kwon Department of Game Software Hoseo UniversityAsan-siKorea Department of Artificial Intelligence and Data Science Korea Military AcademySeoulKorea

Enhancing the sense of presence of participants is an important issue in terms of security awareness for remote collaboration in extended ***,conventional methods are insufficient to be aware of remote situations and to search for and control remote *** study pro-poses a spatial multi-presence system that simultaneously provides multiple spaces while rapidly exploring these spaces as users perform collaborative work in an extended reality *** proposed system provides methods for arranging and manipulating remote and personal spaces by creating an annular screen that is invisible to the *** user can freely arrange remote participants and their workspaces on the annular *** users can simultaneously view various spaces arranged on the annular screen,they can perform collaborative work while simultaneously feeling the presence of multiple spaces and can be fully immersed in a specific *** addition,the personal spaces where users work can also be arranged through the annular *** to the results of the performance evaluations,users participating in remote collaborative works can visualize the spaces of multiple users simultaneously and feel their presence,thereby increasing their understanding of the ***,the proposed system reduces the time to perform tasks and gain awareness of the emergency in remote workspaces.

关键词： Extended reality spatial presence multi presence security awareness

Stress-induced cardiomyopathy with electrocardiographic ST-segment elevation in a patient with pneumothorax

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World Journal of Emergency Medicine 2020年第4期11卷 260-262页

作者： jun Woo Cho Chi Hoon bae Department of Thoracic and Cardiovascular Surgery School of MedicineCatholic University of DaeguDaeguRepublic of Korea

Dear editor,In many cases,S T-segment changes on electrocardiogram(ECG)are suggestive of acute coronary syndrome,but there may be other causes,[12]such as stress induced ***,reports of such changes in patients with pneumothorax are very rare.[3-1]Here,we report a case of ST-segment elevation due to stress-induced cardiomyopathy in a patient with pneumothorax.

关键词： cardiomyopathy acute patient

Pseudo-C-rpp Semigroups

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Acta Mathematica Sinica,English Series 2010年第4期26卷 629-646页

作者： Xiao Jiang GUO Young bae jun Ming ZHAO Department of Mathematics Jiangxi Normal University Nanchang 330022 P. R. China Department of Mathematics Education and RINS Gyeongsang National University Chinju 660-701 Korea Teaching and Research Section of Mathematics Shangrao Branch of Jiangxi Medical College Shangrao 334000 P. R. China

The aim of this paper is to study a class of right pp semigroups, so-called pseudo-C- rpp semigroups. After obtaining some characterizations of pseudo-C-rpp semigroups, we establish a construction of such semigroups i... 详细信息

关键词： right pp semigroup left normal band strongly rpp semigroup right quasi-normal band right regular band left cancellative monoid

Strangulated small bowel hernia through the port site:A case report

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World Journal of Gastroenterology 2008年第44期14卷 6881-6883页

作者： jun hyun Lee Wook Kim Department of Surgery Holy Family HospitalCollege of MedicineThe Catholic University of KoreaBucheon 420-717South Korea

Port site hernia develops through a fascial or peritoneal layer that was inadequate or not repaired. It is a rare complication of laparoscopic surgery which may lead to serious problems. Here,we present a 77-year-old female,diagnosed with a small bowel hernia through a 10-mm port site. We had performed ten cases of laparoscopy-assisted distal gastrectomy before this case. The patient complained of left lower abdominal pain with a palpable mass. Abdominal CT showed an incarcerated small bowel hernia and the patient underwent segmental resection of the strangulated small bowel through a minimally extended port site incision.

关键词： Port site hernia Strangulated small bowel Minimally extended port site incision