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Torsional vibration analysis of lathe spindle system with unbalanced workpiece

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Journal of Central South University 2011年第1期18卷 171-176页

作者：郭瑞 jang Sung-hyun CHOI Young-Hyu School of Mechatronics Changwon National University

For the purpose of analyzing the torsional vibration caused by the gravitational unbalance torque arisen in a spindle system when it is machining heavy work piece,a 10-DOF lumped parameter model was made for the machine tool spindle system with geared *** using the elementary method and Runge-Kutta method in Matlab,the eigenvalue problem was solved and the pure torsional vibration responses were obtained and *** results show that the spindle system cannot operate in the desired constant rotating speed as far as the gravitational unbalance torque is engaged,so it may cause bad effect on machining *** the torsional vibration increases infinitely near the resonant frequencies,so the spindle system cannot operate normally during these spindle speed ranges.

关键词： unbalanced work piece gravitational unbalance torque torsional vibration spindle system geared transmission

Pancreatic abscess following scrub typhus associated with multiorgan failure

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World Journal of Gastroenterology 2007年第25期13卷 3523-3525页

作者： Sun Young Yi Jung hyun tae Department of Internal Medicine School of Medicine Ewha Womans University Seoul South Korea

Clinical severity of scrub typhus ranges from mild to fatal. Acute pancreatitis with abscess formation is a rare complication among patients with scrub typhus. This paper reports a case of scrub typhus in a 75 years old man with acute pancreatitis with abscess formation and multiorgan failure. Abdominal computed tomography showed multiple infected pancreatic pseudocysts with periopancreatic infiltration. Multiorgan failure was successfully treated with doxycycline, ceftriaxone, and supportive management. The pancreatic abscess was successfully drained percutaneously and the sizes of pseudocysts decreased remarkably.

关键词： Scrub typhus Pancreatitis Pancreaticabscess Multiorgan failure

A scheme for improving computational efficiency of quasi-two-dimensional model

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Journal of Hydrodynamics 2017年第2期29卷 243-250页

作者： tae Uk jang 伍悦滨徐莹孙强 Department of Mechanics KimⅡSung UniversityPyong YangD.P.R.Korea School of Municipal and Environmental Engineering Harbin Institute of TechnologyHarbin 150090China State Key Laboratory of Urban Water Resource and Environment Harbin Institute of TechnologyHarbin 150090China School of Energy and Architecture Harbin University of CommerceHarbin 150028China

The quasi-2D model, taking into account the axial velocity profile in the cross section and neglecting the convective term in the 2-D equation, can more accurately simulate the water hammer than the 1-D model using the cross-sectional mean velocity. However, as compared with the 1-D model, the quasi-2D model bears a higher computational burden. In order to improve the computational efficiency, the 1-D method is proposed to be used to solve directly the pressure head and the discharge in the quasi-2D model in this paper, based on the fact that the pressure head obtained as the solution of the two-dimensional characteristic equation is identical to that solved by the 1-D characteristic equations. The proposed scheme solves directly the 1-D characteristic equations for the pressure head and the discharge using the MOC and solves the 2-D characteristic equation for the axial velocities in order to calculate the wall shear stress. If the radial velocity is needed, it can be evaluated easily by an explicit equation derived from the explicit 2-D characteristic equation. In the numerical test, the accuracy and the efficiency of the proposed scheme are compared with two existing quasi-two-dimensional models using the MOC. It is shown that the proposed scheme has the same accuracy as the two quasi-2D models, but requires less computational time. Therefore, it is efficient to use the proposed scheme to simulate the 2-D water hammer flows.

关键词： Water hammer method of characteristics numerical scheme pipe quasi-2D model

Examining global warming factors using self-organizing map and Granger causality network:a case from South Korea

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Ecological Processes 2023年第1期12卷 140-150页

作者： Thakur Dhakal tae-Su Kim Do-Hun Lee Gab-Sue jang Department of Life Science Yeungnam UniversityGyeongsan 38541Republic of Korea National Institute of Ecology Seocheon 33657Republic of Korea

Background Understanding and patterning the possible causal variables of global warming is attributed to the development of effective prevention and mitigation strategies for climate ***,we aimed to pattern and visualize the possible causal variables of global warming and measure the causality between *** We patterned and visualized the time series(103 years,from 1918 to 2020)of global surface temperature(GTemp)data with the gross domestic product(GDP)per capita,human population(Pop),and carbon dioxide(CO_(2))emissions of South Korea using a self-organizing map(SOM)and examined the causable local feature of global warming using the Granger causality(GC)*** time-series data were trained and mapped in 4×4 SOM grids,and causality networks between variables were examined using multivariate Granger test *** SOM patterned 103 years of data,and a dominant cluster contained continuous time-series data from 2007 to ***,the CO_(2)emissions of South Korea were obtained as a predictable unidirectional causal variable for GTemp from GC *** on data from the past 34 years,significant causality(p-value=0.01)was observed with the integrated effect of Pop,GDP,and CO_(2)on *** This study patterned the time-series data using SOM and examined the causal relationship between variables using the GC *** study framework could be used as a reference by future scholars,ecologists,and the United Nations Sustainable Development Goals.

关键词： Climate change Ecology Self-organizing map Sustainable development goal Greenhouse gas

A combination strategy of functionalized polymer coating with Ta ion implantation for multifunctional and biodegradable vascular stents

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Journal of Magnesium and Alloys 2021年第6期9卷 2195-2207页

作者： Kwang-Hee Cheon Cheonil Park Min-Ho Kang Suhyung Park Jinyoung Kim Seol-Ha Jeong Hyoun-Ee Kim hyun-Do Jung tae-Sik jang Department of Materials Science and Engineering Seoul National UniversitySeoul 08826Republic of Korea Department of Chemical and Biological Engineering Seoul National UniversitySeoul 08826Republic of Korea Department of Biomedical-Chemical Engineering Catholic University of KoreaBucheon-si 03083Republic of Korea Department of Biotechnology The Catholic University of KoreaBucheon-si 14662Republic of Korea Department of Materials Science and Engineering Chosun UniversityGwangju 61452Republic of Korea

Biodegradable stents made of magnesium(Mg)and its alloys have been developed to minimize persistent inflammation or in-stent restenosis,which are the main problems for permanent ***,their rapid corrosion behavior under physiological conditions leads to poor vascular compatibility and premature structural failure,which remains an important unsolved clinical ***,we demonstrate a new strategy for solving this problem by combining poly(ether imide)(PEI)coating and subsequent tantalum(Ta)ion *** PEI coating covers the whole surface of the Mg stent uniformly via a spray coating technique and provides Mg with superior corrosion resistance and stable sirolimus-carrying *** ion implantation is conducted by a sputtering-based plasma immersion ion implantation technique only onto the luminal surface of the PEI-coated Mg *** extremely short processing time(<30 s)permits preservation of the PEI coating’s corrosion protection ability and sirolimus loading *** addition,a Ta-implanted skin layer that forms on the topmost surface of the PEI coating plays an effective role in not only preventing a rapid release of sirolimus from the surface but also improving the PEI coating’s surface *** on in vitro cellular response and blood compatibility tests,Ta ion implantation leads to the improvement of endothelial cell adhesion/proliferation and suppression of platelet adhesion/activation regardless of sirolimus *** results indicate that the combination of PEI coating and Ta ion implantation has significant innovative potential to provide excellent vascular compatibility and prevent in-stent restenosis and thrombosis.

关键词： Magnesium stent Biodegradability Tantalum Plasma immersion ion implantation Multifunctionality

Efficacy of 0.5-L vs 1-L polyethylene glycol containing ascorbic acid as additional colon cleansing methods for inadequate bowel preparation as expected by last stool examination before colonoscopy

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World Journal of Clinical Cases 2019年第1期7卷 39-48页

作者： Joon hyun Cho Eun Joo Goo Kyeong Ok Kim Si hyung Lee Byung Ik jang tae Nyeun Kim Division of Gastroenterology and Hepatology Department of Internal Medicine Yeungnam University College of Medicine

BACKGROUND No consensus has been reached in patients suspected of having inadequate bowel preparation regarding optimal salvage methods, which negatively affects the efficacy and quality of colonoscopy. The most ideal and reasonable rescue option involves early suspicion and identification of patients with inadequate preparation before sedation, additional oral ingestion of a suitable preparation formulation, and same-day *** To compare 0.5-L and 1-L polyethylene glycol containing ascorbic acid(PEG +Asc) as additional bowel cleansing methods after a 2-L split-dose PEG + Asc regimen in patients with expected inadequate bowel preparation before *** Individuals with expected inadequate bowel preparation based on last stool form, such as turbid liquid, particulate liquid, or liquid with small amounts of feces, were randomized to either a 0.5-L PEG + Asc group or a 1-L PEG + Asc group. The primary endpoint was bowel preparation as assessed using the Aronchick bowel preparation scale(ABPS) and Boston bowel preparation scale(BBPS) scores. The secondary endpoints were cecal intubation time, withdrawal time, polyp detection rate(PDR), adenoma detection rate(ADR), individual compliance with additional PEG + Asc, and patient *** Initially, 98 patients were included, but 8 were later excluded due to withdrawal of consent to participate in the study. Adequate bowel preparation(as assessed by ABPS) was observed in 80.9%(38/47) of subjects in the 0.5-L group and in88.4%(38/43) of subjects in the 1-L group(P = 0.617). Mean total BBPS was 6.7 points in the 0.5-L group and 7.0 points in the 1-L group(P = 0.458). ADRs and PDRs were similar in the two groups, and cecal intubation and withdrawal times were not significantly different. However, mean patient satisfaction score was significantly higher in the 0.5-L group(P = 0.041).CONCLUSION The bowel cleaning efficacy of additional 0.5-L PEG + Asc was not inferior to that of 1-L PEG + Asc. Add

关键词： Inadequate bowel preparation Additional colon cleansing Colonoscopy Polyethylene glycol

Aging Analysis Framework of Windows-Based Systems through Differential-Analysis of System Snapshots

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Computers, Materials & Continua 2022年第12期73卷 5091-5102页

作者： Eun-tae jang Sung Hoon Baek Ki-Woong Park SysCore Lab Sejong UniversitySeoul05006Korea Department of Computer System Engineering Jungwon UniversityChungcheongbuk-do28024Korea

When aWindows-based system is used for an exceedingly long time,its performance degrades,and the error occurrence rate tends to *** is generally called system *** investigate the reasons for system aging,various studies have been conducted within the range of the operating system kernel to the user ***,finding an accurate reason for system performance degradation remains challenging research *** this study,system monitoring was conducted by dividing a system into‘before software installation,’‘after software installation,’and‘after software removal.’We confirmed that when a software installed in a system is removed,various system elements,such as storage and memory,are not restored to the level prior to the software ***,we established a hypothesis regarding the performance degradation of a computer system owing to repeated software installation/removal operations,investigated the correlation between system aging and repeated software installation/removal operations,and proposed a system aging analysis framework for analyzing the reason behind system *** the proposed system aging analysis framework,we aim to forcibly age a Windows-based system by repeating the software installation/removal operation by utilizing the system forced aging *** framework identifies the elements affecting system performance through a differential data analysis of the system time-series data extracted by the system performance extraction and system component snapshot ***,the aging analysis framework presented in this study is expected to be effectively utilized as an index for studying system aging.

关键词： System aging virtual machine system analysis

Transcriptomic Responses of Garlic(Allium sativum L.)to Heat and Drought Stresses

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Phyton-International Journal of Experimental Botany 2023年第11期92卷 3077-3090页

作者： Seung Hee Eom tae Kyung hyun Department of Industrial Plant Science and Technology Chungbuk National UniversityCheongju28644Korea

Heat and drought are prominent abiotic stressors that limit crop productivity and yield,particularly concerning climate change;therefore,understanding the molecular mechanisms underlying plant stress responses is crucial for stress-tolerant crop *** study conducted a transcriptomic analysis to elucidate how garlic(Allium sativum L.)responds to drought and heat stress *** libraries were generated to identify differentially expressed genes(DEGs)induced by drought and heat *** classification and clustering analysis of DEGs revealed stress-specific gene expression ***,cell wall-related genes were implicated in the drought response,whereas heat stress was associated with heat stress transcription factors and heat shock *** results provide essential information for future studies on stress tolerances in garlic.

关键词： Differentially expressed gene drought heat garlic transcriptome

Endoscopic prevention of post-endoscopic retrograde cholangiopancreatography pancreatitis

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World Journal of Gastroenterology 2014年第44期20卷 16582-16595页

作者： tae Hoon Lee Do hyun Park Division of Gastroenterology Department of Internal Medicine Soonchunhyang University School of Medicine Cheonan Hospital Division of Gastroenterology Department of Internal Medicine University of Ulsan College of Medicine Asa Medical Center

Post-endoscopic retrograde cholangiopancreatography(ERCP) pancreatitis(PEP) is not an uncommon adverse event but may be an avoidable complication. Although pancreatitis of severe grade is reported in 0.1%-0.5% of ERCP patients, a serious clinical course may be lethal. For prevention of severe PEP, patient risk stratification, appropriate selection of patients using noninvasive diagnostic imaging methods such as magnetic resonance cholangiopancreatography or endoscopic ultrasonography(EUS), and avoidance of unnecessary invasive procedures, are important measures to be taken before any procedure. Pharmacological prevention is also commonly attempted but is usually ineffective. No ideal agent has not yet been found and the available data conflict. Currently, rectal non-steroidal anti-inflammatory drugs are used to prevent PEP in high-risk patients, but additional studies using larger numbers of subjects are necessary to confirm any prophylactic effect. In this review, we focus on endoscopic procedures seeking to prevent or decrease the severity of PEP. Among various cannulation methods, wire-guided cannulation,precut fistulotomy,and transpancreatic septostomy are *** pancreatic stent placement,which is the best-known prophylactic method,is reviewed with reference to the ideal stent type,adequate duration of stent placement,and stentrelated ***,we comment on other treatment alternatives,and make the point that further advances in EUS-guided techniques may afford useful PEP prophylaxis.

关键词： Endoscopic retrograde cholangiopancreatography Prevention Pancreatitis Pancreas stent Cannulation Fistulotomy