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In situ thickness control of black phosphorus field-effect transistors via ozone treatment

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Nano Research 2016年第10期9卷 3056-3065页

作者： Suhyun Kim younghun jung Jong-young lee Gwan-Hyoung lee Jihyun Kim Department of Chemical and Biological Engineering Korea University Seou102841 Republic of Korea Department of Materials Science and Engineering Yonsei University Seou103722 Republic of Korea

A simple and reproducible method to control the thickness of black phosphorus flakes in real time using a UV/ozone treatment is demonstrated. Back-gated black phosphorus field-effect transistors （FETs） were fabricated using thick black phosphorus flakes obtained by thinning of black phosphorus, as oxygen radicals generated by UV irradiation formed phosphorus oxides on the surface. In order to monitor the thickness effect on the electrical properties, the fabricated FETs were loaded in the UV/ozone chamber, where both the optical （micro-Raman spectroscopy and optical microscopy） and electrical properties （current-voltage characteristics） were monitored in situ. We observed an intensity decrease of the Raman modes of black phosphorus while the field-effect mobility and on/off ratio increased by 48% and 6,800%, respectively. The instability in ambient air limits the investigation and implementation of ultra-thin black phosphorus. However, the method reported in this study allowed us to start with thick black phosphorous flakes, providing a reliable approach for optimizing the electrical performance of black phosphorus-based electronic devices. We believe that these results can motivate further studies using mono- and few-layer black phosphorus.

关键词： black phosphorus in situ thinning UV/ozone treatment

Process simulation and economic analysis of reactor systems for perfluorinated compounds abatement without HF effluent

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Frontiers of Chemical Science and Engineering 2016年第4期10卷 526-533页

作者： Boreum lee Sunggeun lee Ho young jung Shin-Kun Ryi Hankwon Lim Department of Advanced Materials and Chemical Engineering Catholic University of Daegu Gyeongbuk 38430 Korea Department of Environment and Energy Engineering C-honnam National University-Gwangju 61186 Korea Korea Institute of Energy Research Daejeon 34129 Korea

New and efficient proposed to treat perfluorinated reactor systems were compounds via catalytic decomposition. One system has a single reactor （S-1）, and another has a series of reactors （S-2）. Both systems are capable of producing a valuable CaF2 and eliminating toxic HF effluent and their feasibility was studied at various temperatures with a commercial process simulator, Aspen HYSYS. They are better than the conventional system, and S-2 is better than S-1 in terms of CaF2 production, a required heat for the system, natural gas usage and CO2 emissions in a boiler, and energy consumption. Based on process simulation results, preliminary economic analysis shows that cost savings of 12.37% and 13.55% were obtained in S-2 at 589.6 and 621.4℃compared to S-1 at 700 and 750 ℃, respectively, for the same amount of CaF2 production.

关键词： perfluorinated compounds (PFCs) CF4 pro-cess simulation economic analysis

Deformation prediction of porcelain-enameled steels with strain history by press forming and high-temperature behavior of coating layer

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中国有色金属学会会刊：英文版 2012年第S3期22卷 838-844页

作者： young-Ki SON Chan-Joo lee jung-Min lee Byung-Min KIM School of Mechanical Engineering Pusan National University Dongnam Regional Division Korea Institute of Industrial Technology

Porcelain enamel coatings were widely applied for the protection of steel products because they offered high corrosion protection,resistance to heat and abrasion,high hardness,hygiene and ease of *** typical process to produce enameled steels is roughly divided into two stages:the first stage consists of a forming process to give the desired shape to a steel substrate,and the second stage consists of a firing process to bond enamel frits on the *** firing process requires a high temperature above 800 °C,which may lead to austenitic transformation and severe thermal deformation of the steel *** aim of this study is to develop a finite element analysis (FE analysis) technique to predict the mechanical and thermal deformations of the enameled steels during forming and any further enameling process,including *** FE analysis involves analyzing the strain history of the steel substrate,which comprises the stress and thickness distributions of the substrate and its deformed shape,and the high-temperature behavior of the enamel coating *** validity of the FE analysis is verified through the U-bending test and firing test with various numbers and positions of enamel coating layers on the *** results reveal that the FE analysis results agree well with the experimental results with 8% error.

关键词： porcelain enamel firing process finite element analysis enameled steel thermal deformation

Effective parameters on diameter of carbon nanotubes by plasma enhanced chemical vapor deposition

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中国有色金属学会会刊：英文版 2012年第S3期22卷 712-716页

作者： Kang young JEONG Hyun Kyung jung Hyung Woo lee National Core Research Center for Hybrid Materials Solution Hybrid Graduate SchoolPusan National University Department of Diagnostic Radiology Inje University College of MedicineHaeundae Paik Hospital

The effective parameters on the diameter of carbon nanotubes (CNTs) by plasma enhanced chemical vapor deposition (PECVD) were *** lots of influential parameters,the effects of the catalytic film thickness and the pretreatment plasma power on the growth of CNTs were *** results show that the size of catalytic islands increases by increasing the thickness of catalytic layer,but the density of CNTs *** pretreatment duration time of 30 s is the optimal condition for growing CNTs with about 50 nm in *** increasing the pretreatment plasma power,the diameter of CNTs decreases ***,the diameter of CNTs does not change drastically from 80 to 120 *** uniformly grown CNTs with the diameter of 50 nm are obtained at the pretreatment plasma power of 100 W.

关键词： carbon nanotubes catalytic film thickness pretreatment plasma power plasma enhanced chemical vapor deposition

2.47 GPa grade ultra-strong 15Co-12Ni secondary hardening steel with superior ductility and fracture toughness

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Journal of Materials Science & Technology 2021年第7期66卷 36-45页

作者： young-Kyun Kim Kyu-Sik Kim young-Beum Song jung Hyo Park Kee-Ahn lee Department of Materials Science and Engineering Inha UniversityIncheon22212Republic of Korea Agency for Defense Development(ADD) Yuseong-guDaegeon34186Republic of Korea

This study investigated the effect of multi-step heat treatment on the microstructure, mechanical properties and fracture behavior of thick 15 Co-12 Ni secondary hardening steel. As-quenched sample was found to have elongated prior austenite grain(PAG) and coarse lenticular martensitic structure. On the other hand, heat-treated sample was observed to have fine lenticular martensitic structure due to fine PAG size and a lot of nano-sized carbides. Also, after heat treatment, nano-scale reverted austenite film was formed at the martensite interfaces. The heat-treated sample showed 2.47 GPa superior tensile strength and superior elongation of about 12 %. The high strength was mainly due to fine block size and high number density of nano-sized carbides. The average value of plane strain fracture toughness(KIC) was 29.3 MPa m1/2, which indicated a good fracture toughness even with the high tensile strength. The tensile fracture surface was observed to have ductile fracture mode(cup-and-cone) and the formation of about ~1 μm ultra-fine dimples. In addition to this, nano-sized carbides were observed within the *** findings suggested that the nano-sized carbide had a positive effect not only on the strength but also on the ductility of the alloy. The fractured surface after toughness test, also showed ductile fracture mode with a lot of dimples. Based on the above results, correlation among microstructural evolution,deformation and fracture mechanisms along the heat-treatment was also discussed.

关键词： Ultra-high strength High Co-Ni secondary hardening steel Microstructure Tensile properties Fracture toughness Reverted austenite

Does prostate-specific antigen (PSA)mass or free PSA mass improve the accuracy of predicting total prostate volume in relation to obesity in men with biopsy-proven benign prostatic hyperplasia?

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Asian Journal of Andrology 2019年第1期21卷 86-91页

作者： Jin-Woo jung young Dong Yu young Ju lee jung Jun Kim Hak Min lee Jong Jin Oh Sangchul lee Sang Wook lee Sang Eun lee Seong Jin Jeong Department of Urology Catholic Kwandong Univerisity International St.Mary's HospitalIncheon 22711Korea Department of Urology Seoul National University Bundang HospitalSeongnam 13620Korea Department of Urology Kangwon National University School of MedicineChuncheon 24341Korea

We evaluated whether the prostate-specific antigen (PSA)mass or free PSA (fPSA)mass (i.e.,absolute amount of total circulating PSA or fPSA protein,respectively),versus serum PSA or fPSA concentration,improves the accuracy of predicting the total prostate volume (TPV)in relation to *** men whose multicore (≥12)transrectal prostate biopsy was negative,586 who had a PSA of <10 ng ml^-1 and underwent the fPSA test prior to biopsy were *** PSA mass or fPSA mass (pg)was calculated by multiplying the serum level by plasma *** each TPV cut-off point (30 ml,40 ml,and 50 ml),the areas under the receiver operating characteristics curve (AUCs)of each variable were compared in obesity-based *** of fPSA and fPSA mass for predicting TPV were significantly larger than those for PSA and PSA mass by 8.7%-12.1%at all cut-off points. Subgroup analyses based on obesity showed that,although PSA mass and fPSA mass enhanced accuracy by 4%(P =0.031)and 1.8%(P =0.003),respectively,for determining TPVs of ≥30 ml and ≥50 ml in obese and overweight men,they did not improve the accuracy in most other combinations of the degrees of obesity with TPV cut-off ***,compared with serum PSA or fPSA,the absolute amount of PSA or fPSA protein mass improved the accuracy of predicting TPV in obese men very minimally and only for certain TPV cut-off ***,these indicators may not provide clinically meaningful improvement in predicting TPV in obese men.

关键词： benign prostatic hyperplasia obesity prostate volume prostate-specific antigen mass

^(27)Al MAS-NMR study of inorganic polymer formation at ambient temperature

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 182-187页

作者： Sang-Wook AHN Hee-Soo lee Wan-Hee YANG jung-Woo lee young-Keun JEONG National Core Research Center for Hybrid Materials Solution Pusan National University School of Material Science and Engineering Pusan National University INTChem Co. Ltd.

Inorganic polymers are a novel class of materials formed by the polymerization of silicon, aluminium and oxygen species to form an amorphous three-dimensional framework structure. The basis of this process is the alkaline solutions to induce a certain amount of Si and AI atoms to dissolve from a feedstock such as aluminosilicate. A study of 27A1 MAS-NMR was carried out in an attempt to understand the reaction mechanism of the inorganic polymerization at ambient temperature. Scanning electron microscopy （SEM） and X-ray diflYactometry （XRD） were also employed to establish the composition and microstructure of the inorganic polymerization. Specimens were prepared with different A1/Si mole ratios from the starting materials. The higher the AI content, the more sufficient the AI atoms that can combine with SiO4, and the longer the reaction time, the more the bonded Si--O--A1--O polymer structure, and then the higher the A1 content, the fewer the octahedral A1 with a uniform Si--O--A1--O structure in four directions, because four AI atoms are combined with SiO4, resulting in a uniform Si--O--AI--O structure in four directions. The results show that they have an amorphous microstructure.

关键词： inorganic polymer amorphous tetrahedral

Combined Insights from Leachate Structure and Microstructure Characteristics for Eating Quality of Convenience Rice Processed by Super-Heated and Pressurized Steam Technologies

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Rice science 2024年第4期31卷 475-488,I0035,I0036页

作者： Mingyo HA Hyo-young JEONG Ju Hun lee Hyun-jung CHUNG Division of Food and Nutrition Chonnam National UniversityGwangju 61186South Korea Department of Biotechnology College of Life Sciences and BiotechnologyKorea UniversitySeoul 02841South Korea Division of Food Science&Culinary Arts Shinhan UniversityGyeonggi 11644South Korea

Convenience rice has become widely popular due to its easy availability for cooking. This study investigated the starch structure and composition of leachate and the microstructure of reheated convenience rice using novel processing technologies: super-heated steaming(SHS), auto-electric cooking(AEC), and pressurized-steam cooking(PSC). Additionally, the effect of two different target water contents(58% and 63%) was also evaluated. The PSC_63% sample had the highest total solids and amylopectin amount in the leachate. The amylopectin amount in the leachate differed significantly based on the targeted water content. Morphological characterization revealed that the swelling of starch and the coated layer on the surface of rice grains were most pronounced in the PSC_63% sample due to the pressure processing. The textural hardness of the AEC_58% sample was much higher than that of the other samples. The PSC_63% sample had the highest textural adhesiveness value, which can be attributed to the highest amylopectin amount in the leachate. Sensory characterization showed that the PSC_63% sample had the highest glossiness, whiteness, moistness, and overall acceptability. The principal component analysis score plots presented substantial differences in the leachate and textural and sensory characteristics of reheated convenience rice among the different processing technologies.

关键词： reheated convenience rice starch structure leachate multi-scale structure eating quality processing technology

Analysis of expanded criteria to select candidates for active surveillance of low-risk prostate cancer

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Asian Journal of Andrology 2015年第2期17卷 248-252,I0008,I0009页

作者： jung Ki Jo Hart Sol lee young Ik lee Sang Eun lee Sung Kyu Hong Department of Urology Seoul National University Bundang Hospital Seongnam Korea.

We aimed to analyze the value of each criterion for clinically insignificant prostate cancer （PCa） in the selection of men for active surveillance （AS） of low-risk PCa. We identified 532 men who were treated with radical prostatectomy from 2006 to 2013 who met 4 or all 5 of the criteria for clinically insignificant PCa （clinical stage 〈 T1, prostate specific antigen [PSA] density 0.15, biopsy Gleason score 〈 6, number of positive biopsy cores 〈 2, and no core with 〉 50% involvement） and analyzed their pathologic and biochemical outcomes. Patients who met all 5 criteria for clinically insignificant PCa were designated as group A （n -- 172）, and those who met 4 of 5 criteria were designated as group B （n = 360）. The association of each criterion with adverse pathologic features was assessed via logistic regression analyses. Comparison of group A and B and also logistic regression analyses showed that PSA density 0.15 ng ml-1 and high （〉7） biopsy Gleason score were associated with adverse pathologic features. Higher （〉 Tlc） clinical stage was not associated with any adverse pathologic features. Although 〈 3 positive cores were not associated with any adverse pathology, 〉4 positive cores were associated with higher risk of extracapsular extension. Among potential candidates for AS, PSA density ~ 0.15 ng ml-~ and biopsy Gleason score ~ 6 pose significantly higher risks of harboring more aggressive disease. The eligibility criteria for AS may be expanded to include men with clinical stage T2 tumor and 3 positive cores.

关键词： prediction prostate prostatectomy prostatic neoplasms risk