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Effect of molybdenum on interfacial properties of titanium carbide reinforced Fe composite

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Journal of Materials Science & Technology 2022年第12期107卷 252-258页

作者： Seungchan cho Junghwan Kim Ilguk Jo Jae hyun Park Jaekwang Lee hyun-Uk Hong Bong Ho Lee Wook Ryol Hwang Dong-Woo Suh Sang-Kwan Lee Sang-Bok Lee Composites Research Division Korea Institute of Materials Science(KIMS)Changwon 51508South Korea Advanced Materials Engineering Dong-Eui UniversityBusan 47340South Korea Department of Aerospace and Software Engineering Gyeongsang National UniversityJinju 52828South Korea Department of Physics Pusan National UniversityBusan 46241South Korea Department of Materials Convergence and System Engineering Changwon National UniversityChangwon 51140South Korea Center for Core Research Facilities Daegu Gyeongbuk Institute of Science and TechnologyDaegu 42988South Korea School of Mechanical Engineering Gyeongsang National UniversityJinju 52828South Korea Graduate Institute of Ferrous Technology Pohang University of Science and TechnologyGyeongbuk 37673South Korea

This study shows that the mechanical strength of the composite of Fe matrix and titanium carbide(Ti C)ceramic particles is significantly enhanced with addition of molybdenum(Mo) atoms. Ti C reinforced Fe(Fe-0.2C-7Mn) composites with and without Mo were fabricated by a liquid pressing infiltration(LPI)process and the effect of Mo on interfacial properties of TiC–Fe composite was investigated using atomic probe tomography(APT) analysis, molecular dynamics(MD) simulations, first-principle density functional theory(DFT), and thermodynamic calculations. First, DFT calculations showed that total energies of the Mo-doped Ti C–Fe superlattices strongly depend on the position of Mo defects, and are minimized when the Mo atom is located at the TiC/Fe interface, supporting the probable formation of MoC-like interphase at the TiC/Fe interface region. Then, APT analysis confirmed the DFT predictions by finding that about6.5 wt.% Mo is incorporated in the Ti C–Fe(Mo) composite and that sub-micrometer thick(Ti,Mo)C interphase is indeed formed near the interface. The MD simulations show that Mo atoms migrate to the Mo-free TiC–Fe interface at elevated temperatures and the mechanical strength of the interface is considerably enhanced, which is in good agreement with experimental observations.

关键词： Metal matrix composites(MMCs) Titanium carbide Fe matrix composite Infiltration Molybdenum Interfacial property

Serial evaluation of myocardial function using the myocardial performance index in Kawasaki disease

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World Journal of Pediatrics 2018年第3期14卷 259-268页

作者： Eun Song Song Somy Yoon Joo hyun cho Eun Mi Yang Hwa Jin cho Young Youn choi Jae Sook Ma Gwang Hyeon Eom Young Kuk cho Department of Pediatrics Chonnam National University HospitalChonnam National University Medical School42 Jebong-roDong-guGwangju 501-757South Korea Department of Pharmacology and Medical Research Center for Gene Regulation Chonnam National University Medical School160 Baekseo-roDong-guGwangju 61469South Korea Department of Pediatrics KS HospitalGwangjuSouth Korea

Background Kawasaki disease (KD) is known as systemic vasculitis, and more than half of the patients with KD have myo-carditis, which can induce ventricular dysfunction. In this study, we evaluate left ventricular (LV) dysfunction in patients with KD based on the myocardial performance index (MPI) using pulse Doppler (PD) and tissue Doppler imaging (TDI), from the acute to convalescent phases. Methods We retrospectively studied 89 children diagnosed with KD from January 2010 to August 2012. We assessed the presence of coronary artery lesions (CALs) and the LV ejection fraction, PD-MPI, and TDI-MPI at diagnosis, and 2, 14, and 56 days after intravenous immunoglobulin (IVIG) treatment. We enrolled 70 healthy children as a control group. Results The ejection fraction in patients with KD at diagnosis (67.3 ± 0.9%) was lower than that in the control group (69.8 ± 0.8%,P = 0.035), and the LV TDI-MPIs for patients with KD at diagnosis (0.49 ± 0.01) and 2 days after IVIG treatment (0.48 ± 0.01) were higher than those in the control group (0.45 ± 0.01,P = 0.002,P = 0.033, respectively). No signifi cant diff erences were found in the LV dysfunction between the patients with complete and incomplete KD. Septal TDI-MPIs in patients with KD with CAL at diagnosis (0.52 ± 0.02) were higher than those in patients with KD without CAL (0.47 ± 0.01,P = 0.019). Conclusions Transient LV dysfunction occurred in patients with complete and incomplete KD in the acute stage. In patients with KD with CAL at diagnosis, the LV dysfunction was more prominent. The PD-MPI and TDI-MPI are useful parameters for assessing LV function in patients with KD.

关键词： Kawasaki disease Myocardial function Myocardial performance index Tissue Doppler imaging

Intrahepatic biliary cystadenoma:Is there really an almost exclusively female predominance?

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World Journal of Gastroenterology 2011年第25期17卷 3073-3074页

作者： Ho hyun Kim Young Hoe Hur Yang Seok Koh chol Kyoon cho Jin Woong Kim Department of Surgery Chonnam National University Medical School Department of Radiology Chonnam National University Medical School

Biliary cystic tumors,such as cystadenomas and cystadenocarcinomas,are rare cystic tumors of the liver,accounting for less than 5% of all intrahepatic cysts of biliary *** cystadenomas have been known to occur predominantly in women (> 85%),and 38%-44% of biliary cystadenocarcinomas have occurred in *** wrote this letter to comment on a brief article (World J Gasteroenterol 2011 January 21;17(3):361-365) regarding a case of intrahepatic biliary cystic neoplasm treated with *** adenoma-carcinoma sequence is the possible mechanism of *** the carcinogenesis of biliary cystadenocarcinoma occurs in the adenoma-carcinoma sequence,we believe that the male-to-female ratio of cystadenoma should be higher than the incidence rate that has been reported to date.

关键词： Biliary cystadenoma Cystadenocarcinoma Carcinogenesis Incidence

The Sensing Behavior to Volatile Organic Compounds Gas on Polypyrrole Sensor under Humidity Condition

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稀有金属材料与工程 2006年第A3期35卷 65-66页

作者： Jae-hyun cho Joon-Boo Yu Sung-Ok Sohn Duk-Dong Lee Jeung-Soo Huh Department of Material Science Metallurgy Kyungpook National UniversitySangyuk-Dong 1370DaeguKorea School of Electronic Engineering Kyungpook National UniversitySangyuk-Dong 1370DaeguKorea

Polypyrrole (PPy) powder was synthesized by chemical polymerization at 0℃under atmospheric condition and its layer was prepared by dip coating method on the alumina substrate with interdigitated *** influence of relative humidity (RH 0～70%) to PPy sensor was *** measuring temperature was fixed at 25℃.Methanol and benzene were used as target *** analytic techniques were examined to observe changes in the properties of PPy *** sensitivity of PPy sensor to water vapor was linearly increased with the increasing *** the relative humidity increase from 0% to 70%,the sensitivities to methanol and benzene vapor were reduced,and reduction ratio of sensitivity was 94%, 92.5% at RH 70%,respectively.

关键词： VOCs polypyrrole humidity effect gas sensor

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

Screw penetration of the iliopsoas muscle causing late-onset pain after total hip arthroplasty: A case report

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World Journal of Clinical Cases 2021年第32期9卷 10006-10012页

作者： hyung-Seok Park Sang-Hong Lee Hong-Man cho hyun-Bai choi Suenghwan Jo Department of Orthopaedic Surgery Chosun University HospitalGwangju 61453South Korea Department of Orthopedics Gwangju Veterans HospitalGwangju 62284South Korea

BACKGROUND Postoperative pain following total hip arthroplasty(THA)may occur in a few patients but may pose a significant challenge to surgeons if the etiology is not ***,we report the case of a patient who developed late-onset pain following THA due to screw penetration of the iliopsoas *** SUMMARY We report the case of a 77-year-old man who developed inguinal pain 7 years after *** the symptoms resembled that of iliopsoas impingement by the acetabular cup,the pain resolved only when the supplementary acetabular screw protruding through the ilium was *** was performed using the pararectus *** patient was able to ambulate pain-free immediately after *** A protruded screw through the ilium may penetrate the iliopsoas muscle,causing pain following *** may resolve with the decompression of the protruded screw.

关键词： Acetabular cup Iliopsoas impingement Para-rectus approach Screw penetration Total hip arthroplasty Case report

重庆市绿色空间景观格局与PM_(2.5)浓度时空相关性

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地球科学与环境学报 2024年第1期46卷 25-37页

作者：苟爱萍李皖新王江波上海应用技术大学生态技术与工程学院上海201418 南京工业大学建筑学院江苏南京211816

空气中的细颗粒物对人民群众身体健康产生严重威胁,探究绿色空间景观格局对PM_(2.5)浓度的影响,有助于通过调整绿色空间格局降低PM_(2.5)浓度。以重庆市1980~2020年土地利用遥感监测数据和PM_(2.5)浓度数据作为基础数据,通过景观格局指... 详细信息

空气中的细颗粒物对人民群众身体健康产生严重威胁,探究绿色空间景观格局对PM_(2.5)浓度的影响,有助于通过调整绿色空间格局降低PM_(2.5)浓度。以重庆市1980~2020年土地利用遥感监测数据和PM_(2.5)浓度数据作为基础数据,通过景观格局指数法、空间自相关分析研究绿色空间景观格局及PM_(2.5)浓度变化特征,再通过时空地理加权回归(GTWR)模型研究绿色空间景观格局指数变化对PM_(2.5)浓度的影响及其时空异质性。结果表明:①重庆市PM_(2.5)浓度从1980年至2010年逐渐上升,2010年至今逐渐降低;同时,其空间分布具有显著聚集特征,主要显示为东部低-低聚集、西部高-高聚集的特征。②林地、草地和耕地的面积指数(TA)、斑块密度指数(PD)和斑块连接度指数(COHESION)与PM_(2.5)浓度具有显著的相关性。其中,林地面积指数呈负影响,耕地、草地面积指数呈正影响;林地、草地斑块密度指数呈正影响,耕地斑块密度指数呈负影响;林地、草地和耕地斑块连接度指数均呈负影响。③主城都市区内,草地面积指数和耕地斑块密度指数对PM_(2.5)浓度的负影响较强。渝东北三峡库区城镇群和渝东南武陵山区城镇群内,林地聚合度指数(AI)、斑块密度指数和斑块连接度指数以及耕地面积指数对PM_(2.5)浓度的影响较强。

关键词：绿色空间景观格局指数消减效应 PM_(2.5)浓度空间自相关分析时空地理加权回归模型时空异质性重庆

Segmental artery injury during transforaminal percutaneous endoscopic lumbar discectomy:Two case reports

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World Journal of Clinical Cases 2022年第33期10卷 12345-12351页

作者： wan-Jae cho Ki-Won Kim hyung-Youl Park Bo-Hyoung Kim Jun-Seok Lee Department of Orthopedic Surgery Yeouido St.Mary’s HospitalCollege of MedicineCatholic University of KoreaSeoul 07345South Korea Department of Orthopedic Surgery Eunpyeong St.Mary’s HospitalCollege of MedicineCatholic University of KoreaSeoul 03312South Korea

BACKGROUND Since Kambin experimentally induced arthroscopy to treat herniated nucleus pulposus,percutaneous endoscopic lumbar discectomy(PELD)has been *** branch of the segmental artery around the neural foramen may be damaged during PELD using the transforaminal *** report 2 rare cases in which segmental artery injury that occurred during PELD was treated with emergency *** SUMMARY In case 1,a 31-year-old man was transferred to our emergency department with left lower quadrant abdominal pain after PELD at a local *** spine magnetic resonance imaging after the surgery showed a hematoma of the left retroperitoneal area and the psoas muscle *** suspicion of vascular injury,arteriography was *** and blood leakage from the left 4th lumbar segmental artery into the abdominal cavity were *** transarterial embolization was performed using fibered microcoils for bleeding of the segmental *** case 2,a 75-year-old woman was transferred to our emergency department with low blood pressure,right flank pain,and drowsy mental status after PELD at a local *** the patient arrived at the emergency room,the blood pressure decreased from 107/55 mmHg to 72/47 *** blood pressure *** suspicion of vessel injury,arteriography was performed,and the right 4th lumbar segmental artery rupture was *** transarterial embolization was performed for bleeding of segmental *** We were able to find the bleeding focus by angiography and treat the injury of the segmental artery successfully through emergency transarterial embolization.

关键词： Percutaneous endoscopic lumbar discectomy Segmental artery injury Transarterial embolization Angiography Case report

Posturographic Evaluation of Dizziness Complaining Patients under Suspicion to Develop Parkinson's Disease

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Neuroscience & Medicine 2011年第1期2卷 28-33页

作者： hyun cho 不详

Although the typical clinical signs of Parkinson disease (PD) are tremor, rigidity, bradykinesia, and postural instability, PD is preceded by a preclinical phase during which neuronal degeneration develops without typical symptoms. More general nonspecific symptoms including dizziness have also been described to predate the typical PD signs for several years. All subjects were selected among patients in the Willis Hospital (Pusan, South of Korea), with complaints of diz-ziness from September 2009 to September 2010 and the baseline neurological screening and clinical ENT examination, to which the results were within the normal range. At baseline, 113 participants underwent neurological screening and provided information on dizziness. Of those participants, 103 were enrolled including 63 subjects in the control group. We used posturography. It allows quantitative assessment of vestibular-spinal component of body balance. The parame-ter of average speed of pressure center displacement to the lateral plan (VMX) and antero-posterior plan (VMY), which presented statistically significant differences between the groups except VMX with closed eyes. (p = 0.008 and p = 0.012, with closed eyes). With open eyes, only VMY showed significant difference between the groups (p = 0.010). In this study, the patients with dizziness and subjective complaints related to typical clinical signs of PD complaints presented higher instability in the orthostatic position than the control group of patients with dizziness and without such complaint. It could suggest that dizziness may be one symptom of preclinical PD and progress to overt postural instability. It is believed that a stepwise approach with a simple and inexpensive initial screening test of preclinical PD is required.

关键词： Parkinson Disease Postural Instability Neuronal Degeneration Posturography