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Effects of Momentum Ratio and Weber Number on Spray Half Angles of Liquid Controlled Pintle Injector

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Journal of Thermal Science 2015年第1期24卷 37-43页

作者： Min Son Kijeong Yu Jaye Koo Oh Chae Kwon Jeong soo kim Korea Aerospace University School of Aerospace and Mechanical Engineering Korea Aerospace University School of Mechanical Engineering Sungkyunkwan University Department of Mechanical Engineering Pukyong National University

A pintle injector is advantageous for throttling a liquid rocket engine and reducing engine weight. This study ex- plores the effects of momentum ratio and Weber number at various injection conditions on spray characteristics of the pintle injector for liquid-gas propellants. A liquid sheet is injected from a center pintle nozzle and it is broken by a gas jet from an annular gap. The pressure drops of propellants, and the pintle opening distance were consi- dered as control variables; using 0.1 -1.0 as a bar for the pressure drop of the liquid injection, a 0.01-4）.2 bar for the pressure drop of gas jet and a 0.2 - 1.0 mm for the pintle opening distance. The discharge coefficient was de- creased linearly before the pintle opening distance of 0.75 mm and then, the coefficient was slightly increased. Spray images were captured by a CMOS camera with high resolution. Then, the shadow and reflected images were analyzed. Spray distributions were measured by a pattemator with an axial distance of 50 mm from a pintle tip. Finally, the spray half angles had an exponentially decreasing correlation as a momentum ratio divided by the Weber number. Also, the spray half angles from the spray distribution were underestimated compared to those measured from the captured images.

关键词： Pintle Injector Spray Half Angle Spray Distribution Visualization

Characteristics of machined surface controlled by cutting tools and conditions in machining of brittle material

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中国有色金属学会会刊：英文版 2009年第B09期19卷 194-201页

作者： Yong-Woo kim soo-Chang CHOI Jeung-Woo PARK Deug-Woo LEE Department of Nano Fusion Technology Pusan National University Department of Mechanical Design Engineering Chosun University Department of Nanosystem and Nanoprocess Engineering Pusan National University

One of the ultra-precision machining methods was adapted for brittle material as well as soft material by using multi-arrayed diamond tips and high speed spindle. Conventional machining method is too hard to control surface roughness and surface texture against brittle material because the particles of grinding tools are irregular size and material can be fragile. Therefore, we were able to design tool paths and machine controlled pattern on surface by multi-arrayed diamond tips with uniform size made in MEMS fabrication and high speed spindle, and the maximum speed was about 3×105 r/min. We defined several parameters that can affect the machining surface. Those were multi-array of diamond tips (n×n), speed of air spindle and feeding rate. The surface roughness and surface texture can be controlled by those parameters for micro machining.

关键词：加工表面脆性材料条件控制刀具路径表面粗糙度特征高速主轴加工方法

The effectiveness of emotion-focused art therapy on the resilience and self-image of emergency physicians

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World Journal of Emergency Medicine 2022年第6期13卷 479-484页

作者： soo Kyung Eo Chanwoong kim Kyung Hye Park Eun Kyung Eo Graduate School of Art Therapy at CHA University Pocheon 11160Republic of Korea Department of Emergency Medicine Chung-Ang University College of MedicineSeoul 06974Republic of Korea Department of Medical Education Yonsei University Wonju College of MedicineWonju 26426Republic of Korea Department of Emergency Medicine Wonju Severance Christian HospitalWonju 26426Republic of Korea Department of Emergency Medicine Soonchunhyang University Bucheon HospitalBucheon 14584Republic of Korea

INTRODUCTION Resilience refers to the quality of being able to overcome adversity.[1]Studies conducted in the United States[2]and China[3]following the 2019 coronavirus disease(COVID-19)pandemic reported reduced resilience levels among medical *** resilience levels are associated with low burnout levels among residents.[4]Physician burnout affects patients’safety and quality of care.[5]In particular,emergency physicians(EPs)are more prone to exhaustion or poor resilience,as their turnover intention tends to be higher.[6]Therefore,improving EPs’resilience is imperative.

关键词： image physician overcome

Origin of superior low-cycle fatigue resistance of an interstitial metastable high-entropy alloy

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Journal of Materials Science & Technology 2022年第20期115卷 115-128页

作者： Seyed Amir Arsalan Shams Jae Wung Bae Jae Nam kim Hyoung Seop kim Taekyung Lee Chong soo Lee Graduate Institute of Ferrous Technology Pohang University of Science and TechnologyPohang 37673Republic of Korea Department of Materials Science and Engineering Pohang University of Science and TechnologyPohang 37673Republic of Korea School of Mechanical Engineering Pusan National UniversityBusan 46241Republic of Korea

In this study, the deformation behaviors and related microstructural evolutions were investigated in either monotonic or cyclic deformation modes in an interstitial metastable high-entropy alloy. These investigations aimed to reveal the mechanisms underlying the superior low-cycle fatigue(LCF) life of this alloy.A thermomechanical process was applied to induce fine-grained(FG) and coarse-grained(CG) microstructures in Fe–30Mn–10Co–10Cr–0.4C(atomic percentage) alloy. Their superior combination of strength and ductility was attributed to the appearance of deformation-induced ε-martensite and the presence of carbon. The CG alloy showed a greater volume fraction of ε-martensite than the FG alloy in the monotonic deformation mode, and vice versa in the cyclic mode. Such a disparity was interpreted in light of the back-stress effect of the relaxed γ-grain boundaries in the latter mode. Meanwhile, the γ-to-ε phase transformation under cyclic loading at low strain amplitudes(0.4%) barely led to an improved fatigue life as compared with that at higher strain amplitudes(≥ 0.55%). The high reversibility of partial dislocation motions under cyclic loading and delaying the formation of dislocation cells through the martensitic transformation could explain why the alloys investigated in this study exhibited a superior LCF life compared with high-entropy alloys reported in previous studies.

关键词： High-entropy alloy Transformation-induced plasticity Monotonic deformation Cyclic deformation Low-cycle fatigue Stacking faults

Inflammatory pathways in pathological neovascularization in retina and choroid: a narrative review on the inflammatory drug target molecules in retinal and choroidal neovascularization

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Annals of Eye Science 2021年第3期6卷 13-29页

作者： soo-Young kim Younghwa kim Youngman Oh Department of Pharmaceutics Virginia Commonwealth UniversityRichmondVAUSA Department of Biology Virginia Commonwealth UniversityRichmondVAUSA Department of Emergency Medical Technology Kyungil UniversityGyeongsanGyeongbukSouth Korea Department of Pathology Virginia Commonwealth UniversityRichmondVAUSA Massey Cancer Center Virginia Commonwealth UniversityRichmondVAUSA

Objective:We review inflammatory drug targets in retinal and choroidal neovascularization(NV)in narrative ***:Vascular remodeling and angiogenesis are processes typically associated with wound-healing mechanisms intended to minimize ischemia and maintain tissue *** the eye,however,these actions primarily deteriorate tissue homeostatic recovery,and could even contribute to the progress of severe conditions,e.g.,*** in diabetic retinopathy(DR)and age-related macular degeneration(AMD)is the primary cause of vision loss in working-age and elderly *** treatment of anti-vascular endothelial growth factor(VEGF)agents has limited action efficacy,working in less than 50%*** cellular and molecular networks associated in retinal vascular remodeling may provide an insight to develop novel therapeutic ***:Here,we highlight ocular cells-endothelial,mural,retinal pigment epithelium(RPE),glial and macrophages,as well as inflammatory molecules-such as the complement system,stromal derived factor-1,chemokine CXC receptor-4,inflammasome,interleukin-18,programed cell death ligand-1,insulin-like growth factor(IGF)and sphigosin-1-phosphate receptor,associated with retinal and choroidal NV,and discuss their recent and future therapeutic ***:A deeper understanding on pathogenesis,pathobiology including ocular immunobiology of retinal and choroidal NV will pave the way to expand and overleap the current therapeutic approach.

关键词： SDF-1/CXCR4 axis inflammasome programmed cell death ligand-1(PD-L1) insulin-like growth factor(IGF) sphigosin-1-phosphate(S1P)

Fabrication of high-strength duplex nanoporous Cu by dealloying a dual-phase Mg-Cu precursor alloy

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Journal of Magnesium and Alloys 2020年第3期8卷 910-916页

作者： Si-Young Lee soo-Min Baek Eun-Ji Gwak Na-Ri Kang Ju-Young kim Su-Hyeon kim Jung Gu Lee Sung soo Park School of Materials Science and Engineering Ulsan National Institute of Science and TechnologyUlsan 44919Republic of Korea Korea Institute of Materials Science Changwon 51508Republic of Korea School of Materials Science and Engineering University of UlsanUlsan 44610Republic of Korea

Duplex nanoporous Cu was successfully fabricated by dealloying a dual-phase Mg-Cu precursor alloy consisting of intermetallic Mg2Cu and *** duplex nanoporous Cu with embedded nanoporous struts exhibited highly enhanced strength compared to the typical monolithic nanoporous Cu under both compressive and flexural test conditions at room temperature;the duplex np-Cu sample exhibited a 12 times higher compressive strength and a 40 times greater flexural strength than the monolithic np-Cu *** responsible for the strength enhancement in the duplex nanoporous Cu are discussed.

关键词： Mg-Cu alloy Nanoporous Cu Dealloying Duplex structure Strength

Second to fourth digit ratio： a predictor of adult penile ength

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Asian Journal of Andrology 2011年第5期13卷 710-714页

作者： In Ho Choi Khae Hawn kim Han Jung Sang Jin Yoon soo Woong kim Tae Beom kim Department of Urology Gachon University Gil Hospital Incheon Korea Department of Urology Seoul National University College of Medicine Seoul Korea

The second to fourth digit ratio （2D：4D） has been proposed as a putative biomarker for prenatal testosterone and covaries with the sensitivity of the androgen receptor （AR）. Both prenatal testosterone and the AR play a central role in penile growth. In this study, we investigated the relationship between digit ratio and penile length. Korean men who were hospitalized for urological surgery at a single tertiary academic centre were examined in this study, and 144 men aged 20 years or older who gave informed consent were prospectively enrolled. Right-hand second- and fourth-digit lengths were measured by a single investigator prior to measurement of penile length. Under anaesthesia, flaccid and stretched penile lengths were measured by another investigator who did not measure nor have any the information regarding the digit lengths. Univariate and multivariate analysis using linear regression models showed that only height was a significant predictive factor for flaccid penile length （univariate analysis： r=0. 185, P=-0.026; multivariate analysis： r=-0.172, P=0.038） and that only digit ratio was a significant predictive factor for stretched penile length （univariate analysis： r=-0.216, P=0.009; multivariate analysis： r=-0.201, P=0.024; stretched penile length=-9.201 xdigit ratio ＋ 20.577）. Based on this evidence, we suggest that the digit ratio can predict adult penile size and that the effects of prenatal testosterone may in part explain the differences in adult penile length.

关键词： digit ratio flaccid penile length stretched penile length

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World Journal of Clinical Cases 2021年第24期9卷 7205-7211页

作者： So-My Koo Ki-Up kim Yang-Ki kim soo-Taek Uh Department of Internal Medicine Soonchunhyang University Seoul HospitalSeoul 04401South Korea

BACKGROUND Epidermal growth factor receptor tyrosine kinase inhibitors(EGFR-TKIs)are tolerable drugs used for patients with EGFR-mutant advanced non-small cell lung cancer(NSCLC).Serious adverse reactions are uncommon compared with cytotoxic *** SUMMARY A 52-year-old man presented with general weakness and *** had been taking erlotinib for 11 mo to treat *** pathological diagnosis from the right upper lobe mass was adenocarcinoma with an EGFR mutation in exon 21(L858R).He had previously received paclitaxel/carboplatin,gemcitabin/vinorelbine chemotherapy,stereotactic radiosurgery for brain metastasis,and whole-brain radiotherapy as treatment for *** diagnosed the patient with acute myeloid leukemia(AML).During the induction and consolidation chemotherapy for AML,the erlotinib was *** complete remission of the AML was achieved,since the lung masses were increased,pemetrexed/cisplatin for the NSCLC was *** two cycles of chemotherapy,the cytopenia was *** relapse occurred with the same *** Therapy-related acute myeloid neoplasm(t-MN)is a rare but fatal late *** a patient may be taking EGFR-TKIs,the possibility of t-MN should be *** studies are needed to determine whether EGFR-TKI usage is a predisposing factor for t-MN.

关键词： Acute myeloid leukemia Erlotinib Neoplasm,second primary Non-small cell lung cancer Case report

Comparison between sodium iodate and lipid peroxide murine models of age-related macular degeneration for drug evaluation-a narrative review

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Annals of Eye Science 2022年第1期7卷 86-105页

作者： soo-Young kim Haohua Qian Department of Pharmaceutics Department of BiologyVirginia Commonwealth UniversityRichmondVAUSA Center for Nanomedicine Wilmer Eye InstituteDepartment of OphthalmologyJohns Hopkins University of MedicineBaltimoreMDUSA Visual Function Core National Eye InstituteNational Institutes of HealthBethesdaMDUSA

Objective:In this review,non-transgenic models of age-related macular degeneration(AMD)are discussed,with focuses on murine retinal degeneration induced by sodium iodate and lipid peroxide(HpODE)as preclinical study ***:AMD is the most common cause of vision loss in a world with an increasingly aging *** major phenotypes of early and intermediate AMD are increased drusen and autofluorescence,Müller glia activation,infiltrated subretinal microglia and inward moving retinal pigment epithelium(RPE)*** AMD may progress to advanced AMD,characterized by geography atrophy and/or choroidal neovascularization(CNV).Various transgenic and non-transgenic animal models related to retinal degeneration have been generated to investigate AMD pathogenesis and pathobiology,and have been widely used as potential therapeutic evaluation ***:Two retinal degeneration murine models induced by sodium iodate and HpODE are *** pathological features and procedures of these two models are *** addition,practical protocol and material preparation and assessment methods are ***:Retina degeneration induced by sodium iodate and HpODE in mouse eye resembles many clinical aspects of human AMD and complimentary to the existent other animal ***,standardization of procedure and assessment protocols is needed for preclinical *** studies of HpODE on different routes,doses and species will be valuable for the future extensive *** many merits of murine studies,differences between murine and human should be always considered.

关键词： Retina degeneration retinal pigment epithelium(RPE) photoreceptor microglia