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Nanotechnology and Precision Engineering 2020年第3期3卷 141-155页

作者： suk bum kwon Aditya Nagaraj Hae-Sung Yoon Sangkee Min Department of Mechanical Engineering University of Wisconsin-Madison1513 University AvenueMadisonWI 53706United States of America School of Aerospace and Mechanical Engineering Korea Aerospace University76 Hanggongdaehak-roDeogyang-guGoyang-siGyeonggi-do 10540Republic of Korea

In this paper, the modified slip/fracture activation model has been used in order to understand the mechanism of ductile-brittle transition on the R-plane of sapphire during ultra-precision machining by reflecting direction of resultant force. Anisotropic characteristics of crack morphology and ductility of machining depending on cutting direction were explained in detail with modified fracture cleavage and plastic deformation parameters. Through the analysis, it was concluded that crack morphologies were mainly determined by the interaction of multiple fracture systems activated while, critical depth of cut was determined by the dominant plastic deformation parameter. In addition to this, by using proportionality relationship between magnitude of resultant force and depth of cut in the ductile region, an empirical model for critical depth of cut was developed.

关键词： Ductile-brittle transition Crack morphology Single crystal sapphire Deformation mechanism Orthogonal cutting Ultra-precision machining

Liquid Metal Grid Patterned Thin Film Devices Toward Absorption‑Dominant and Strain‑Tunable Electromagnetic Interference Shielding

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Nano-Micro Letters 2024年第11期16卷 541-553页

作者： Yuwen Wei Priyanuj Bhuyan suk Jin kwon Sihyun Kim Yejin Bae Mukesh Singh Duy Thanh Tran Minjeong Ha Kwang‑Un Jeong Xing Ma Byeongjin Park Sungjune Park Department of Polymer‑Nano Science and Technology Department of Nano Convergence EngineeringJeonbuk National UniversityJeonju 54896Republic of Korea School of Chemical Engineering Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Composites Research Division Korea Institute of Materials ScienceChangwon 51508Republic of Korea School of Materials Science and Engineering Gwangju Institute of Science and TechnologyGwangju 61005Republic of Korea School of Materials Science and Engineering and Sauvage Laboratory for Smart MaterialsHarbin Institute of Technology(Shenzhen)ShenzhenGuangdong 518055People’s Republic of China

The demand of high-performance thin-film-shaped deformable electromagnetic interference(EMI)shielding devices is increasing for the next generation of wearable and miniaturized soft *** highly reflective conductive materials can effectively shield EMI,they prevent deformation of the devices owing to rigidity and generate secondary electromagnetic pollution ***,soft and stretchable EMI shielding thin film devices with absorption-dominant EMI shielding behavior is *** devices consist of liquid metal(LM)layer and LM grid-patterned layer separated by a thin elastomeric film,fabricated by leveraging superior adhesion of aerosol-deposited LM on *** devices demonstrate high electromagnetic shielding effectiveness(SE)(SE_(T) of up to 75 dB)with low reflectance(SER of 1.5 dB at the resonant frequency)owing to EMI absorption induced by multiple internal reflection generated in the LM grid ***,the excellent stretchability of the LM-based devices facilitates tunable EMI shielding abilities through grid space adjustment upon strain(resonant frequency shift from 81.3 to 71.3 GHz@33%strain)and is also capable of retaining shielding effectiveness even after multiple strain *** newly explored device presents an advanced paradigm for powerful EMI shielding performance for next-generation smart electronics.

关键词： Absorption-dominant electromagnetic interference shielding Liquid metals Soft and stretchable electronics Thin film devices Tunable electromagnetic interference shielding

Survival benefit of concurrent chemoradiotherapy for advanced ampulla of Vater cancer

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World Journal of Clinical Cases 2024年第2期12卷 267-275页

作者： Chae Hwa kwon Hyung Il Seo Dong Uk Kim Sung Yong Han suk Kim Nam Kyung Lee Seung Baek Hong Ji Hyun Ahn Young Mok Park Byeong Gwan Noh BioMedical Research Institute Pusan National University HospitalBusan 49241South Korea Department of Surgery Pusan National University School of Medicine and Biomedical Research InstitutePusan National University HospitalBusan 49241South Korea Department of Internal Medicine Pusan National University School of Medicine and Biomedical Research InstitutePusan National University HospitalBusan 49241South Korea Department of Radiology Pusan National University School of Medicine and Biomedical Research InstitutePusan National University HospitalBusan 49241South Korea Department of Pathology and Biomedical Research Institute Pusan National University HospitalBusan 49241South Korea

BACKGROUND Currently,there is no standard adjuvant therapy for patients with resected ampulla of Vater(AoV)*** To evaluate the effectiveness of adjuvant concurrent chemoradiotherapy(CCRT)in patients with advanced AoV cancer who underwent curative *** This single-centered,retrospective study included 29 patients with advanced AoV cancer who underwent pancreaticoduodenectomy between 2006 and *** impact of CCRT on advanced AoV cancer was *** The 1-,3-,and 5-yr recurrence-free survival(RFS)rates for patients with advanced AoV cancer were 82.8%,48.3%,and 40.8%,respectively,and the overall survival(OS)rates were 89.7%,62.1%,and 51.7%,***-cular invasion was found to be a significant risk factor for RFS and OS in patients with advanced AoV cancer in the univariate analysis,whereas T stage and lymph node metastasis were significantly associated with OS in the multivariate *** to the patients who did not receive adjuvant CCRT,those who received adjuvant CCRT did not show statistically significant improvements in the RFS and OS,although they had a significantly lower average age and significantly higher platelet-to-lymphocyte *** Adjuvant CCRT did not improve survival outcomes in patients with advanced AoV *** findings contribute to existing knowledge on the effectiveness of CCRT in this patient population and provide important insights for clinical decision-making.

关键词： Advanced ampulla of Vater cancer Adjuvant concurrent chemoradiotherapy Recurrence Survival Vater cancer

A Study of the Influence of Air-knife Tilting on Coating Thickness in Hot-dip Galvanizing

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Journal of Thermal Science 2009年第3期18卷 262-267页

作者： Tae-Seok CHO Young-Doo kwon Soon-bum kwon School of Mechanical Engineering Kyungpook National University

Gas wiping is a decisive operation in hot-dip galvanizing process. In special, it has a crucial influence on the thickness and uniformity in coating film, but may be subsequently responsible for the problem of splashing. The progress of industry demands continuously the reduction of production costs which may relate directly with the increase of coating speed, and the speed up of coating results in the increase of stagnation pressure in gas wiping system in final. It is known that the increase of stagnation pressure may accompany a harmful problem of splashing in general. Together with these, also, from the view point of energy consumption, it is necessary to design a nozzle optimally. And there is known that the downward tilting of nozzle using in air knife system is effective to prevent in somewhat the harmful problem of splashing. In these connections, first, we design a nozzle with constant expansion rate. Next, for the case of actual coating conditions in field, the effects of tilting of the constant expansion rate nozzle are investigated by numerical analysis. Under the present numerical conditions, it was turned out that the nozzle of constant expansion rate of p = having a downward jet angle of 5^0 is the most effective to diminish the onset of splashing, while the influence of small tilting of the nozzle on impinging wall pres- sure itself is not so large.

关键词： Air-knife Constant expansion rate nozzle Impinging pressure Wall shear stress Hot-dip galvanizing Coating thickness Splashing

Experimental and Computational Studies on Coanda Nozzle Flow for the Air Knife Application

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Journal of Thermal Science 2007年第2期16卷 164-169页

作者： Soon-bum kwon Dong-Won LEE Young-Doo kwon School of Mechanical Engineering Kyungpook National University1370Sankyuk-dongDaegu 702-701Korea

To control the film thickness of zinc in the process of continuous hot-dip galvanizing, it is known from the early days that the gas wiping through an air knife is the most effective one. The gas wiping using in galvanizing process brings about a problem of splashing from the strip edge for a certain high speed of coating. So, in the present study, the effects of the deflection angle of Coanda nozzle on jet structure and the distribution of impinging pres- sure at the plate surface are investigated numerically and experimentally. In numerical analysis, the governing equations consisted of three-dimensional time dependent full Navier-Stokes equations, standard k-ε turbulence model to solve turbulent stTess and so on are employed. In experiment, 16 channel pressure scanning valve and 3-axis auto traversing unit are used to measure the impinging pressure at the strip surface. As a result, it is found that the smaller the deflection angle for the same nozzle slit of air knife is, the larger the impinging pressure is. To reduce the size of separation bubble and to enhance the cutting ability, it is recommendable to use an air knife with the Coanda nozzle.

关键词： Air knife Coanda effect edge splashing gas wiping hot-dip galvanizing impinging jet

Evaluation of particle growth systems for sampling and analysis of atmospheric fine particles

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Particuology 2011年第6期9卷 606-610页

作者： Dae Seong Kim Sang bum Hong Jung-Taek kwon Kihong Park Department of Environmental Science and Engineering Gwangju Institute of Science and Technology Korea Polar Research Institute Laboratory of Toxicology College of Veterinary Medicine Seoul National University

Three types of water-based condensational growth systems, which can enable particles to grow in size to facilitate sampling and subsequent chemical analysis, were evaluated. The first one is a mixing type growth system where aerosols are mixed with saturated water vapor, the second one is a thermal diffusive growth system where warm flow enters cold-walled tube, and the third one is a laminar flow type where cold flow enters a warm wet-wall tube. Hygroscopic sodium chloride （NaCl）, ammonium sulfate （（NH4）2SO4） and ammonium nitrate （NH4N03）, and non-hygroscopic polystyrene latex （PSL） particles, in the size range of 50-400 nm, were used to determine their growth factors through the growth systems. Our data showed that the third-type growth system could enable particles to grow most efficiently regardless of their hygroscopic property. Collection efficiency of particles in the size range of 0.05-2.5 μm, in a continuous aerosol sampler after they passed through the third-type growth system was about 100%, suggesting that the third-type growth system would he the most useful among the tested growth systems for sampling and subsequent chemical analysis of fine and ultrafine particles.

关键词： Particle growth chamber Condensational growth Particle sampler Hygroscopic particles

Characteristics of damaged layer in micro-machining of copper 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 295-300页

作者： Dong-Hee kwon Jeong-suk KIM Myung-Chang KANG Se-Hun kwon Jong-Hwan LEE School of Mechanical Engineering Pusan National University National Core Research Center for Hybrid Materials Solution Pusan National University Department of Mechatronics Busan College of Korea Polytechnic Ⅶ

The study on damaged layer is necessary for improving the machinability in micro-machining because the damaged layer affects the micro mold life and micro machine parts. This study examined the ultra-precision micro-machining characteristics, such as cutting speed, feed rate and cutting depth, of a micro-damaged layer produced by an ultra-high speed air turbine spindle. The micro cutting force, surface roughness and plastic deformation layer were investigated according to the machining conditions. The damaged layer was measured using optical microscope on samples prepared through metallographic techniques. The scale of the damaged layer depends on the cutting process parameters, particularly, the feed per tooth and axial depth of the cut. According to the experimental results, the depth of the damaged layer is increased by increasing the feed per tooth and cutting depth, also the damaged layer occurs less in down-milling compared with up-milling during the micro-machining operation.

关键词：机械加工性微观特征损伤层铜材样品制备技术微型机器切削速度切削深度

Risk stratification for disease progression in pT3 prostate cancer after robot-assisted radical prostatectomy

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Asian Journal of Andrology 2017年第6期19卷 700-706页

作者： Jeong Hee Hong Young suk kwon Isaac Yi Kim Section of Urologic Oncology Rutgers Cancer Institute of New Jersey Division of Urology Rutgers Robert Wood Johnson Medical School Rutgers The State University of New Jersey New Brunswick NJ 08903 USA Department of Urology Dankook University College of Medicine Cheonan 31116 South Korea.

The aim of this study is to identify optimal patients for adjuvant radiation therapy （ART） in pT3 prostate cancer. The role of ART for patients with adverse pathologic features after radical prostatectomy （RP） has been demonstrated, but over- or under-treatment remains a significant concern. Two-hundred and five patients with pT3NOMO who underwent robot-assisted RP without ART were analyzed. Multivariate Cox proportional regression analyses were used to identify predictors of biochemical recurrence （BCR） and clinical progression （CP）. The estimated 5-year BCR-free survival （BCRFS） and CP-free survival （CPFS） were 52.8% and 85.6%, respectively. Preoperative prostate-specifc antigen （PSA）：〉10 ng m1-1 （hazard ratio [HR]： 3.288-6.027; P = 0.003）, pathologic Gleason score （pGS）：〉8 （HR： 4.146; P = 0.014）, and lymphovascular invasion （LVI）（HR： 2.167; P = 0.026） were associated with BCR. Based on these factors, a risk stratification tool was developed. Patients with no risk factors （PSA 〈10 ng m1-1, pGS 6, and absent LVI） showed excellent BCRFS and CPFS at 5 years （91.9% and 100.0%, respectively）, but those with two or more risk factors （PSA ：〉10 ng ml-1, pGS ≥8, or present LVI） had poor BCRFS and CPFS （12.1% and 54.6%, respectively）. In addition, the multivariate analysis revealed that pathologic stage pT3b （HR： 5.393; P = 0.025） was the only predictor of CP. Our study demonstrated the heterogeneity of oncologic outcomes in patients with pT3 prostate cancer. The proposed risk stratification can be used to identify patients who are at risk for disease progression and may aid in identifying the best patients for ART.

关键词： prostatectomy prostate-specific antigen recurrence survival

A comparative study on machine learning-based classification to find photothrombotic lesion in histological rabbit brain images

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Journal of Innovative Optical Health Sciences 2021年第6期4卷 81-89页

作者： Sang Hee Jo Yoonhee Kim Yoon bum Lee Sung suk Oh Jong-ryul Choi School of Biomedical Engineering Daegu Catholic University(DCU)Gyeongsan 38430Republic of Korea Medical Device Development Center Daegu-Gyeongbuk Medical Innovation Foundation(DGMIF) Daegu 41061Republic of Korea Laboratory Animal Center Daegu-Gyeongbuk Medical Innovation Foundation(DGMIF) Daegu 41061Republic of Korea

Recently,research has been conducted to assist in the processing and analysis of histopathological images using machine learning *** this study,we established machine learning-based algorithms to detect photothrombotic lesions in histological images of photothrombosis-induced rabbit *** machine learning-based algorithms for binary classification were applied,and the accu-racies were compared to classify normal tissues and photothrombotic *** lesion classification model consisting of a 3-layered neural network with a rectified linear unit(ReLU)activation function,Xavier initialization,and Adam optimization using datasets with a unit size of 128×128 pixels yielded the highest accuracy(0.975).In the validation using the tested histological images,it was confirmed that the model could identify regions where brain damage occurred due to photochemical ischemic *** the development of machine learning-based photothrombotic lesion classi-fication models and performance comparisons,we confirmed that machine learning algorithms have the potential to be utilized in histopathology and various medical diagnostic techniques.

关键词： Machine learning histopathological images photothrombotic lesion rabbit brain binary classification logistic regression multi-layer neural networks

Classification of Regular Planar Graphs with Diameter Two

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Acta Mathematica Sinica,English Series 2007年第3期23卷 411-416页

作者： Moo Young SOHN Sang bum KIM Young Soo kwon Rong Quan FENG Mathematics Changwon National University Changwon 641-773 Korea Mathematics Pohang University of Science and Technology Pohang 790-784 Korea LMAM School of Mathematical Sc-iencesPeking University Beijing 100871 P. R. China

In the present paper, the regular planar graphs with diameter two are classified.

关键词： graph regular diameter planar outer planar