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Development of single-action,two-step clinching system using finite element analysis

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中国有色金属学会会刊：英文版 2009年第B9期19卷 266-270页

作者： Seong-Wook lee Tae-Hyung KIM Geun-jo han Power & Industrial Systems R&D Center Hyosung Corporation Department of Mechanical Engineering Department of Mechanical Engineering Dong-A University

Traditional manufacturing processes for bending and combining the upper and lower heat insulation plates for a car catalytic converter need two kinds of bending dies. This study was carried out to develop a single-action, two-step clinching system for clinching heat insulation plates. To design the operating mechanism for this clinching system, finite element analysis was used to estimate the bending load needed and to predict the bent shape of the heat insulation plate. Then a recovery and cushioning system was designed for the bending die. It is expected that this new process will improve the manufacturing quality of heat insulation plates and will reduce manufacturing cost. And a higher value-added technique for mold and pressing systems was introduced.

关键词：缓冲系统有限元分析开发汽车催化转化器单动模具技术隔热板板弯曲

Sequential disruption of ALV host receptor genes reveals no sharing of receptors between ALV subgroups A, B, and J

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journal of Animal Science and Biotechnology 2019年第2期10卷 410-423页

作者： Hong jo lee Kyung Je Park Kyung Youn lee Yongxiu Yao Venugopal Nair Jae Yong han Sciences and Research Institute of Agriculture and Life SciencesSeoul National UniversitySeoul 08826Korea The Pirbright Institute WokingSurrey GU24 0NFUK.

Background: Previously, we showed that targeted disruption of viral receptor genes in avian leukosis virus(ALV)subgroups using clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9))-based genome editing confers resistance to ALV subgroups B and J. Here, we used the same strategy to target the receptor expressed by ALV subgroup A(TVA) and generate chicken cells resistant to infection by this ***: CRISPR/Cas9-based disruption of exon 2 within the tva gene of DF-1 fibroblasts conferred resistance to infection by ALV subgroup A regardless of whether frameshift mutations were introduced during editing. Conversely,overexpression of the wild-type TVA receptor(wtTVA) by tva-modified DF-1 clones restored susceptibility to ALV subgroup A. The results confirm that exon 2, which contains the low-density lipoprotein receptor class A domain of TVA, is critical for virus entry. Furthermore, we sequentially modified DF-1 cells by editing the tva, tvb, and Na^+/H^+ exchange 1(chNHE1) genes, which are the specific receptors for ALV subgroups A, B, and J, ***: Simultaneous editing of multiple receptors to block infection by different subgroups of ALV confirmed that ALV subgroups A, B, and J do not share host receptors. This strategy could be used to generate cells resistant to multiple viral pathogens that use distinct receptors for cell entry.

关键词： Avian leukosis virus CRISPR/Cas9 Genome editing Host receptor TVA

joint member angle limits of composite beams and CFT square columns

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journal of Central South University 2013年第1期20卷 199-206页

作者： lee Seung-jo lee Kang-Guk Department of Architecture Chosun College of Science & Technology Research Center for Urban Affair Kyungil University

This work aims to understand the relationship between the member angle limit and the energy ratio for 24 test samples of composite beams and CFT square steel tube columns. This work also compares the formula applicability for member angle limit with the previous test result to provide the basic data for the design of composite beam-CFT column. The evaluation of the member angle limit was performed with concrete compressive strength (fC =22.16 MPa, 30.49 MPa), breadth-to-thickness ratio (B/t=25.0, 33.3, 43.5), and axial capacity ratio (N/N0=0, 0.3, 0.4, 0.5) as the main variables of the test samples. For the relationship between the member angle limit (Ru) and the energy ratio (ES/EC ), the test result shows that the energy ratio becomes lower as the axial capacity ratio and the breadth-to-thickness ratio increase. The energy ratio is lower for the Type B test sample compared with that of Types A and C. For the formula suggested by SATO, the test samples are distributed evenly for comparison between test values and the member angle limit; however, other formulas indicate a deviation. Specifically, for the comparison between R u,cal and R u (Test), Maeda's formula shows severe deviation.

关键词： square steel tube axial capacity ratio member angle limit breadth-to-thickness ratio

Regulatory elements and transcriptional control of chicken vasa homologue(CVH)promoter in chicken primordial germ cells

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journal of Animal Science and Biotechnology 2017年第2期8卷 490-500页

作者： So Dam Jin Bo Ram lee Young Sun Hwang Hong jo lee jong Seop Rim Jae Yong han Department of Agricultural Biotechnology Research Institute of Agriculture and Life Sciences College of Agriculture and Life Sciences Seoul National University Institute for Biomedical Sciences Shinshu University

Background： Primordial germ cells（PGCs）, the precursors of functional gametes, have distinct characteristics and exhibit several unique molecular mechanisms to maintain pluripotency and germness in comparison to somatic cells. They express germ cel-specific RNA binding proteins（RBPs） by modulating tissue-specific cis-and trans-regulatory elements. Studies on gene structures of chicken vasa homologue（CVH）, a chicken RNA binding protein, involved in temporal and spatial regulation are thus important not only for understanding the molecular mechanisms that regulate germ cel fate, but also for practical applications of primordial germ cells. However, very limited studies are available on regulatory elements that control germ cel-specific expression in chicken. Therefore, we investigated the intricate regulatory mechanism（s） that governs transcriptional control of ***： We constructed green fluorescence protein（GFP） or luciferase reporter vectors containing the various 5′ flanking regions of CVH gene. From the 5′ deletion and fragmented assays in chicken PGCs, we have identified a CVH promoter that locates at-316 to ＋275 base pair fragment with the highest luciferase activity. Additional y, we confirmed for the first time that the 5′ untranslated region（UTR） containing intron 1 is required for promoter activity of the CVH gene in chicken PGCs. Furthermore, using a transcription factor binding prediction, transcriptome analysis and siR NA-mediated knockdown,we have identified that a set of transcription factors play a role in the PGC-specific CVH gene ***： These results demonstrate that cis-elements and transcription factors localizing in the 5′ flanking region including the 5′ UTR and an intron are important for transcriptional regulation of the CVH gene in chicken PGCs. Final y,this information wil contribute to research studies in areas of reproductive biology, constructing of germ cel-specific synthetic promoter for tracing primordial germ ce

关键词： Chicken Chicken vasa homologue Primordial germ cel Regulatory element siRNA-mediated knockdown

GPU-Driven Scalable Parser for OBJ Models

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journal of Computer Science & Technology 2018年第2期33卷 417-428页

作者： Sunghun jo Yuna Jeong Sungkil lee Department of Software Sungkyunkwan University Suwon 16419 Korea

This paper presents a scalable parser framework using graphics processing units （GPUs） for massive text-based files. Specifically, our solution is designed to efficiently parse Wavefront OBJ models texts of which specify 3D geometries and their topology. Our work bases its scalability and efficiency on chunk-based processing. The entire parsing problem is subdivided into subproblems the chunk of which can be processed independently and merged seamlessly. The within-chunk processing is made highly parallel, leveraged by GPUs. Our approach thereby overcomes the bottlenecks of the existing OBJ parsers. Experiments performed to assess the performance of our system showed that our solutions significantly outperform the existing CPU-based solutions and GPU-based solutions as well.

关键词： 3D model Wavefront OBJ parser GPU

Indolo[3,2,1-jk]carbazole-derived planar electron transport materials realizing high efficiency in green phosphorescent organic light-emitting diodes

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Science China Materials 2023年第11期66卷 4437-4444页

作者： Sejeong Um Unhyeok jo Jun Yeob lee School of Chemical Engineering Sungkyunkwan University 2066Seobu-roJangan-guSuwonGyeonggi16419Republic of Korea SKKU Advanced Institute of Nano Technology Sungkyunkwan University 2066Seobu-roJangan-guSuwonGyeonggi16419Republic of Korea SKKU Institute of Energy Science and Technology Sungkyunkwan University 2066Seobu-roJangan-guSuwonGyeonggi16419Republic of Korea

Two novel electron transporting materials(ETMs),2-(4,6-diphenyl-1,3,5-triazin-2-yl)indolo[3,2,1-jk]-carbazole(DPTrz-ICz)and 5,11-bis(4,6-diphenyl-1,3,5-triazin-2-yl)-2-phenylindolo[3,2,1-jk]carbazole(2DPTrz-ICz),were developed based on the indolo[3,2,1-jk]carbazole(ICz)core,combined with 2,4-diphenyl-1,3,5-triazine(DPTrz).The introduced ICz core in ETM exhibited enhanced intermolecular charge transport properties owing to its planar and rigid geometry and high triplet energy,demonstrating the potential of designing ***,2DPTrz-ICz,featuring high triplet energy of 2.84 eV,effectively prevented triplet exciton quenching and showed increased electron mobility owing to the activation of intermolecular hopping charge transfer facilitated by stacking *** two materials were utilized as ETMs in green phosphorescent organic light-emitting diodes.2DPTrz-ICz exhibited a superior external quantum efficiency of 21.5%,higher than that of the spirobifluorene-derived ETM.

关键词： electron transport layer indolocarbazole efficiency OLED

Flexural-wave-generation using a phononic crystal with a piezoelectric defect

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Applied Mathematics and Mechanics(English Edition) 2023年第8期44卷 1241-1262页

作者： S.H.jo D.lee Department of Mechanical Roboticsand Energy EngineeringDongguk UniversitySeoul 04620Republic of Korea Department of Mechanical Engineering Seoul National UniversitySeoul 08826Republic of Korea

This paper proposes a method to amplify the performance of a flexural-wave-generation system by utilizing the energy-localization characteristics of a phononic crystal(PnC)with a piezoelectric defect and an analytical approach that accelerates the predictions of such wave-generation *** proposed analytical model is based on the Euler-Bernoulli beam *** proposed analytical approach,inspired by the transfer matrix and S-parameter methods,is used to perform band-structure and time-harmonic analyses.A comparison of the results of the proposed approach with those of the finite element method validates the high predictive capability and time efficiency of the proposed model.A case study is explored;the results demonstrate an almost ten-fold amplification of the velocity amplitudes of flexural waves leaving at a defect-band frequency,compared with a system without the ***,design guidelines for piezoelectric-defect-introduced PnCs are provided by analyzing the changes in wave-generation performance that arise depending on the defect location.

关键词： phononic crystal(PnC) defect wave-generation fexural wave analytical model

Mechanically resilient,alumina-reinforced carbon nanotube arrays for in-plane shock absorption in micromechanical devices

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Microsystems & Nanoengineering 2023年第3期9卷 73-81页

作者： Eunhwan jo Hojoon lee Jae-Ik lee jongbaeg Kim School of Mechanical Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul 03722Republic of Korea Department of Neurosurgery Massachusetts General HospitalHarvard Medical School25 Shattuck StBostonMA 02115USA

Microelectromechanical systems(MEMS)are of considerable interest due to their compact size and low power consumption when used in modern *** devices intrinsically incorporate three-dimensional(3D)microstructures for their intended operations;however,these microstructures are easily broken by mechanical shocks accompanying high-magnitude transient acceleration,inducing device *** various structural designs and materials have been proposed to overcome this limit,developing a shock absorber for easy integration into existing MEMS structures that effectively dissipates impact energy remains ***,a vertically aligned 3D nanocomposite based on ceramic-reinforced carbon nanotube(CNT)arrays is presented for in-plane shock-absorbing and energy dissipation around MEMS *** geometrically aligned composite consists of regionally-selective integrated CNT arrays and a subsequent atomically thick alumina layer coating,which serve as structural and reinforcing materials,*** nanocomposite is integrated with the microstructure through a batch-fabrication process and remarkably improves the in-plane shock reliability of a designed movable structure over a wide acceleration range(0-12,000g).In addition,the enhanced shock reliability through the nanocomposite was experimentally verified through comparison with various control devices.

关键词： shock plane arrays

Prediction of characteristic blast-induced vibration frequency during underground excavation by using wavelet transform

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Frontiers of Structural and Civil Engineering 2022年第8期16卷 1029-1039页

作者： Tae Un PAK Guk Rae jo Un Chol han Faculty of Mining Engineering Kim Chaek University of TechnologyPyongyang 999093Democratic People’s Republic of Korea School of Science and Engineering Kim Chaek University of TechnologyPyongyang 999093Democratic People’s Republic of Korea

Blast-induced vibration produces a very complex signal,and it is very important to work out environmental problems induced by *** this study,blasting vibration signals were measured during underground excavation in carbonaceous shale by using vibration pickup CB-30 and FFT analyzer ***,wavelet analysis on the measured results was carried out to identify frequency bands reflecting changes of blasting vibration parameters such as vibration velocity and energy in different frequency *** characteristics are then discussed in view of blast source distance and charge weight per *** analysis of results,it can be found that peak velocity and energy of blasting vibration in frequency band of 62.5–125 Hz were larger than ones in other bands,indicating the similarity to characteristics in the distribution band(31–130 Hz)of main vibration *** frequency bands were affected by blasting source distance,and the frequency band of 0–62.5 Hz reflected the change of charge weight per *** presenting a simplified method to predict main vibration frequency,this research may provide significant reference for future blasting engineering.

关键词： wavelet analysis blast-induced vibration frequency characteristics underground excavation