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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

Glutathione-S-transferase (GSTM1,GSTT1) and the risk of gastrointestinal cancer in a Korean population

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World Journal of Gastroenterology 2009年第45期15卷 5716-5721页

作者： Jin-Mei Piao Min-ho Shin Sun-Seog Kweon Hee Nam Kim Jin-Su choi Woo-Kyun Bae hyun-Jeong Shim Hyeong-Rok Kim Young-Kyu Park Yoo-Duk choi Soo-hyun Kim Department of Preventive Medicine Chonnam National University Medical School Gwangju 501-746 South Korea Jeonnam Regional Cancer Center Chonnam National University Hwasun Hospital Hwasun Jeollanam-do 519-809 South Korea Genome Research Center for Hematopoietic Diseases Chonnam National University Hwasun Hospital Hwasun Jeollanam-do 519-809 South Korea Department of Hematology-Oncology Chonnam National University Hwasun Hospital Hwasun Jeollanam-do 519-809 South Korea Department of Surgery Chonnam National University Hwasun Hospital Hwasun Jeollanam-do 519-809 South Korea Department of Pathology Chonnam National University Medical School Gwangju 501-746 South Korea Department of Laboratory Medicine Chormam National University Medical School Gwangju 501-746 South Korea

AIM： To evaluate the association of glutathione S-trans-ferase mu （GSTM1） and glutathione S-transferase theta （GSTT1） null genotypes with the risk of gastric cancer （GC） and colorectal cancer （CRC） in a South Korean population. METhoDS： We conducted a population-based, large- scale case-control study including 2213 GCs, 1829 CRCs, and 1699 controls. Null and non-null genotypes of GSTM1 and GSI-F1 were determined using realtime PCR. RESULTS： The null genotypes of GSTM1 and GSTT1 were not significantly associated with elevated risk of gastric （OR = 1.070, 95% CI = 0.935-1.224; OR = 1.101, 95% CI = 0.963-1.259, respectively） or colorectal cancer （OR = 1.065, 95% CI = 0.923-1.228; OR = 1.041, 95% CI = 0.903-1.200, respectively）. The frequency of the combined null GST genotype was not different between the two cancer groups and controls. Moreover, smoking, drinking, and age did not modify the association between these genotypes and the risk of gastric or colorectal cancer. CONCLUSION： GSTM1 and GSCI-1 null genotypes were not associated with increased risk of GC or CRC in Koreans.

关键词： Glutathione S-transferase mu Glutathione S-transferase theta Gastric cancer Colorectal cancer South Korean population

Laparoscopic surgery for gastric cancer:Current status and future direction

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Chinese Journal of Cancer Research 2021年第2期33卷 133-141页

作者： So hyun Kang hyung-ho Kim Department of Surgery Seoul National University Bundang HospitalSeongnam 13620Republic of Korea Department of Surgery Seoul National University College of MedicineSeoul 03080Republic of Korea

Gastric cancer is still a major cause of death *** laparoscopic gastrectomy(LG)has gained evidence as a standard treatment for early gastric cancer in the distal stomach,there are still concerns regarding its application for gastric cancer in the upper stomach and advanced gastric ***,LG has shown to have faster recovery,shorter hospital stay,less pain,and less blood loss in many retrospective and prospective *** application of LG has now extended from conventional radical gastrectomy to novel approaches such as function-preserving gastrectomy and sentinel-node navigated *** on the use of laparoscopy in treatment for stage IV gastric cancer are rare,but show that there may be some roles of LG in selected *** the development of new laparoscopic tools that augment human ability,the future of LG should move on from proving non-inferiority to demonstrating superiority compared to the traditional open gastrectomy.

关键词： Laparoscopy stomach neoplasm minimally invasive surgical procedures

BIOCOMPATIBILITY OF A PDMS-COATED MICRO-DEVICE:BLADDER VOLUME MONITORING SENSOR

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Chinese Journal of Polymer Science 2012年第2期30卷 242-249页

作者： Dong Sup Lee Su Jin Kim Jun ho Sohn In Gul Kim Sae Woong Kim Dong Wan Sohn Jong hyun Kim Bumkyoo choi Department of Urology St.Vincent's HospitalCollege of Medicinethe Catholic University of KoreaSuwonKorea Department of Urology Seoul St.Mary's HospitalCollege of Medicinethe Catholic University of KoreaSeoulKorea Department of Urology Yeouido St.Mary's HospitalCollege of Medicinethe Catholic University of KoreaSeoulKorea Department of Mechanical Engineering Sogang UniversitySeoulKorea

We evaluated the biocompatibility of a dimethylpolysiloxane-coated micro-device which had been designed for monitoring real-time bladder volume in previous studies. The extract assay with dimethylpolysiloxane which had been used for coating the micro-device to measure the bladder volume was performed as an in vitro cytotoxicity test. For in vivo biocompatibility testing, the inflammatory responses around the implantation site of the micro-device in subcutaneous tissue of rat were assessed by light microscope with H＆E stain and fluorescence microscope with ED1 stain and von Willebrand factor stain. The averages of cell viability in dimethylpolysiloxane group were 84.6% and 82.3% at 24 h and 72 h incubation, respectively. The qualitative evaluations with light and fluorescence microscope revealed that the inflammatory changes peaked during 2 weeks but almost disappeared at 4 weeks after implantation of devices. The quantitative evaluations for granulation layer formation and neovascularization showed that the thickness of the layer in dimethylpolysiloxane group peaked during 2 weeks but it came to be stabilized at 4 weeks as thin as at 2 weeks in control group, and the frequency of neovascularization was higher in dimethylpolysiloxane group than in control group but it was not increased with time. The dimethylpolysiloxane-coated micro-device is thought be a reliable bio-medical device.

关键词： Dimethylpolysiloxane Devices Biocompatibility testing.

Microstructure and Mechanical Properties of Hyper-eutectic Al-Si Alloys Fabricated by Spray Casting

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Journal of Materials Science & Technology 2008年第1期24卷 48-50页

作者： Min Ryou Chul-hyun Kim Myung-ho Kim School of Materials Science and Engineering Inha University 253 Yonghyun-DongNam-GuIncheon 402-751Korea Dong Yang Piston Co. LTD 1050Singil-DongDonwon-GuAnsanKyungki-DoKorea

Microstructure and mechanical properties of hyper-eutectic Al-Si alloy fabricated by spray casting were in- vestigated and then these results were compared with those by squeeze *** spray-cast specimen was found to have finer Si particles （～5μm） compared to the squeeze-cast specimen （10-25μm）.The tensile strength and elongation of the spray-cast specimen are also higher than those of the squeeze cast *** was considered that the increased mechanical properties of the spray-cast specimen were mainly due to finer size of the Si particles distributed in Al matrix.

关键词： Hyper-eutectic Al-Si alloy Squeeze casting Spray casting

Small sphincterotomy combined with endoscopic papillary large balloon dilation versus sphincterotomy

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World Journal of Gastroenterology 2009年第34期15卷 4298-4304页

作者： hyun Gun Kim Young Koog Cheon Young Deok Cho Jong ho Moon Do hyun Park Tae hoon Lee hyun Jong choi Sang-Heum Park Joon Seong Lee Moon Sung Lee Institute for Digestive Research Digestive Disease Center Soonchunhyang University College of Medicine

AIM： To compare small sphincterotomy combined with endoscopic papillary large balloon dilation （SES ＋ ELBD） and endoscopic sphincterotomy （EST） for large bile duct stones. METhoDS： We compared prospectively SES ＋ ELBD （group A, n = 27） with conventional EST （group B, n = 28） for the treatment of large bile duct stones （≥ 15 mm）. When the stone could not be removed with a normal basket, mechanical lithotripsy was performed. We compared the rates of complete stone removal with one session and application of mechanical lithotripsy. RESULTS： No significant differences were observed in the mean largest stone size （A： 20.8 mm, B： 21.3 mm）, bile duct diameter （A： 21.4 turn, B： 20.5 ram）, number of stones （A： 2.2, B： 2.3）, or procedure time （A： 18 min, B： 19 rain） between the two groups. The rates of complete stone removal with one session was 85% in group A and 86% in group B （P = 0.473）. Mechanical lithotripsy was required for stone removal in nine of 27 patients （33%） in group A and nine of 28 patients （32%, P = 0.527） in group ***： SES ＋ ELBD did not show significant benefits compared to conventional EST, especially for the removal of large （≥ 15 mm） bile duct stones.

关键词： Sphincterotomy Endoscopic Balloon dilatation Cholelithiasis Lithotripsy

Possibility of Solid Hydrometeor Growth Zone Identification Using Radar Spectrum Width

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Advances in Atmospheric Sciences 2023年第2期40卷 317-332页

作者： Sung-ho SUH Eun-ho choi hong-Il KIM Woonseon JUNG Flight Safety Technology Division NARO Space CenterKorea Aerospace Research Institute(KARI)508 Haban-roBongrae-myeonGoheung-gunJeollanam-do 59571Republic of Korea Research Applications Department National Institute of Meteorological Sciences33Seohobuk-roSeoqwipo-siJeju-do 63568Republic of Korea

In this study,the correlation between simulated and measured radar velocity spectrum width(σ_(v))is *** results show that the dendrites growth zones(DGZs)and needles growth zones(NGZs)mostly contain dendrites(DN)and needles(NE),***σ_(v) zones(1.11.2 m s^(-1),a differential reflectivity(ZDR)higher than 0 dB,and a cross-correlation coefficient(ρhv)less than *** contrast,prolate particles with relatively uniform shapes were observed in the NGZ withσ_(v)how that the DN exhibited a largerσ_(v) compared to the NE,and this observedσ_(v) was strongly dependent on the wind fluctuations(v’)due to turbulence or wind *** contrast,the NE exhibited a significantly smallσ_(v)~0.55 m s^(-1),which converges irrespective of v’.In addition,a strong correlation between the measuredσ_(v) values at five radar elevation angles(θ=6.2°,9.1°,13.1°,19°,and 80°)and those simulated in this study confirmed the significance of the analysis results.

关键词： spectrum width weather radar aerodynamic properties dendritic growth zone hydrometeor classifications

Experience of limited pancreatic head resection for management of branch duct intraductal papillary mucinous neoplasm in a single center

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World Journal of Gastroenterology 2009年第23期15卷 2904-2907页

作者： Kwang Yeol Paik Seong ho choi Department of Surgery Kepco Medical Foundation Hanil General Hospital #388-1 Ssangmoon-Dong Dobong-Gu Seoul 132-033 South Korea Department of Surgery Samsung Medical Center College of Medicine Sungkyunkwan University #50 Irwon-Dong Gangnam-Gu Seoul 135-710 South Korea

AIM: To share our surgical experience and the outcome of limited pancreatic head resection for the management of branch duct intraductal papillary mucinous neoplasm (IPMN). METhoDS: Between May 2005 and February 2008, nine limited pancreatic head resections (LPHR) were performed for IPMN of the pancreatic head. We reviewed the nine patients, retrospectively. RESULTS: Tumor was located in the uncinate process of the pancreas in all nine patients. Three patients had stents inserted in the main pancreatic duct due to injury. The mean size of tumor was 28.4 mm. Postoperative complications were found in f ive patients: 3 pancreatic leakages, a pancreatitis, and a duodenal stricture. Pancreatic leakages were improved by external drainage. No perioperative mortality was observed and all patients are recorded alive during the mean follow-up period of 17.2 mo. CONCLUSION: In selected patients after careful evaluation, LPHR can be used for the treatment of branch duct type IPMN. In order to avoid pancreatic ductal injury, preand intra-operative defi nite localization and careful operative techniques are required.

关键词： Limited pancreatic head resection Branchduct type Intraductal papillary mucinous neoplasm

Cytomegalovirus ileo-pancolitis presenting as toxic megacolon in an immunocompetent patient: A case report

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World Journal of Clinical Cases 2020年第3期8卷 552-559页

作者： Joon hyun Cho Joon Hyuk choi Division of Gastroenterology and Hepatology Department of Internal MedicineYeungnam University College of MedicineDaegu 42415South Korea Department of Pathology Yeungnam University College of MedicineDaegu 42415South Korea

BACKGROUND Cytomegalovirus(CMV) enterocolitis presenting in the form of pancolitis or involving the small and large intestines in an immunocompetent patient is rarely encountered, and CMV enterocolitis presenting with a serious complication, such as toxic megacolon, in an immunocompetent adult has only been reported on a few *** SUMMARY We describe the case of a 70-year-old male with no history of inflammatory bowel disease or immunodeficiency who presented with toxic megacolon and subsequently developed massive hemorrhage as a complication of CMV ileopancolitis. The patient was referred to our institute for abdominal pain and distension. Abdominal X-ray showed marked dilatation of ileum and whole colon without air-fluid level, and sigmoidoscopy with biopsy failed to reveal any specific finding. After 7 d of conservative treatment, massive hematochezia developed, and he was diagnosed to have CMV enterocolitis by colonoscopy with biopsy. Although the diagnosis of CMV enterocolitis was delayed, the patient was treated successfully by repeat colonoscopic decompression and antiviral therapy with intravenous *** This report cautions that CMV-induced colitis should be considered as a possible differential diagnosis in a patient with intractable symptoms of enterocolitis or megacolon of unknown cause, even when the patient is nonimmunocompromised.

关键词： Toxic megacolon Cytomegalovirus Enterocolitis Immunocompetent Case report