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MRI鉴别乏血供性胰腺神经内分泌肿瘤与胰腺导管腺癌:回顾性横断面研究

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国际医学放射学杂志 2017年第5期 587-587页

作者： S.K.jeon j.M.Lee I.joo E.S.Lee H.j.Park j.y.jang 张小琨 Department of Radiology Seoul National University Hospital

摘要目的确定对乏血供性胰腺神经内分泌肿瘤(PNET)与胰腺导管腺癌(PDAC)鉴别有价值的MRI特征。材料与方法本回顾性研究经机构伦理委员会批准,无需知情

关键词：胰腺导管腺癌胰腺神经内分泌肿瘤 MRI

胰腺脂肪变性与纤维化:多参数MRI术前定量评估

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国际医学放射学杂志 2016年第3期 313-313页

作者： j.H.yoon j.M.Lee K.B.Lee S.W.Kim M.j.Kang j.y.jang 陈国中 Department of Radiology Seoul National University College of Medicine

摘要目的以组织学分析作为参照标准,评价多参数胰腺MRI包括T2*校正Dixon技术和体素内非相干性运动(IVIM)扩散加权(DW)成像在胰腺脂肪变性和纤维化中的诊断效能,以及MR参数与术后胰瘘之间的关系。材料与方法此回顾性研究已取得伦理委员... 详细信息

摘要目的以组织学分析作为参照标准,评价多参数胰腺MRI包括T2*校正Dixon技术和体素内非相干性运动(IVIM)扩散加权(DW)成像在胰腺脂肪变性和纤维化中的诊断效能,以及MR参数与术后胰瘘之间的关系。材料与方法此回顾性研究已取得伦理委员会许可,无需书面知情同意。

关键词： MRI 纤维化胰腺脂肪变性脂肪分数多参数术前

Experimental and finite element analysis for fracture of coating layer of galvannealed steel sheet

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 111-116页

作者： S.I.KIM j.U.HER y.C.jang y.LEE Sheet Products and Process Research Group POSCO Techology Research Laboratory Department of Mechanical Engineering Chung-Ang University

Mechanical properties of galvannealed (GA) steel sheet used for automotive exposed panel and predicted failure phenomenon of its coating layer were evaluated using finite element method. V-bending test was performed to understand better the fracture of coating layer of GA steel sheet during plastic deformation. yield strength of the coating layer was calculated by using a relative difference between hardness of coating layer measured from the nano-indentation test and that of substrate. To measure shearing strength at the interface between substrate and coating layer, shearing test with two specimens attached by an adhesive was carried out. Using the mechanical properties measured, a series of finite element analyses coupled with a failure model was performed. Results reveal that the fracture of coating layer occurs in an irregular manner at the region where compressive deformation is dominant. Meanwhile, a series of vertical cracks perpendicular to material surface are observed at the tensile stressed-region. It is found that 0.26-0.28 of local equivalent plastic strain exists at the coating and substrate at the beginning of failure. The fracture of coating layer depends on ductility of the coating layer considerably as well.

关键词： galvannealed steel sheet fracture simulation coating layer finite element analysis, failure model

Emissions of Er3+ and yb3+ co-doped SrZrO3 nanocrystals under near-infrared and near-ultraviolet excitations

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journal of Advanced Ceramics 2020年第4期9卷 413-423页

作者： Hyeontae Lim juyeong Lim Soyoung jang y.S.Lee Department of Physics Soongsil UniversitySeoul06978Republic of Korea

In this study,the upconversion(UC)emissions of Er3+and yb3+co-doped SrZrO3 nanocrystals(NCs)were investigated in terms of the thermal annealing temperature and concentration of Er3+ions and compared with the emissions under a near-ultraviolet(near-UV)*** NCs were synthesized by the combustion method,and the as-synthesized NCs were post-annealed at high *** X-ray diffraction patterns revealed that the grain sizes and crystallinity degrees of the samples increased with increasing annealing *** photoluminescence spectra of our samples exhibited strong green and very weak red emissions with the near-UV excitation,originating from the f-f transitions in the Er3+***,under near-infrared(near-IR)excitation,we identified sizable visible emissions at 525,547,and 660 nm in our NCs,which indicated that the UC process successfully occurred in our *** UC emissions were maximized in the NCs with an Er3+concentration of 0.02 and thermal annealing at 1000°*** found that the intensity ratios of red to green emissions increased with increasing annealing *** discussed the differences in the emissions between near-UV and near-IR excitations.

关键词： Er3+and yb3+co-doped SrZrO3 upconversion downshifting nanocrystals combustion method annealing temperature

Degradation of Synthetic Dyeing Wastewater by Underwater Electrical Discharge Processes

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Plasma Science and Technology 2013年第7期15卷 659-665页

作者： S.D.KIM D.I.jang B.j.LIM S.B.LEE y.S.MOK yeongsan River Environment Research Center National Institute of Environmental ResearchGwangju 500-480 Korea Department of Chemical and Biological Engineering Jeju National UniversityJeju 690-756 Korea

Electrical discharge treatments of synthetic dyeing wastewater were carried out with two different systems： underwater pulsed electrical discharge （UPED） and underwater dielectric barrier discharge （UDBD）. Reactive Blue 4 （RB4） and Acid Red 4 （AR4） were used as model contaminants for the synthetic wastewater. The performance of the aforementioned systems was compared with respect to the chromaticity removal and the energy requirement. The results showed that the present electrical discharge systems were very effective for degradation of the dyes. The dependences of the dye degradation rate on treatment time, initial dye concentration, electrical energy, and the type of working gas including air, 02, and N2 were examined. The change in the initial dye concentration did not largely affect the degradation of either RB4 or AR4. The energy delivered to the UPED system was only partially utilized for generating reactive species capable of degrading the dyes, leading to higher energy requirement than the UDBD system. Among the working gases, the best performance was observed with O2. As the degradation proceeded, the concentration of total dissolved solids and the solution conductivity kept increasing while pH showed a decreasing trend, revealing that the dyes were effectively mineralized.

关键词： degradation dyeing wastewater pulsed electrical discharge dielectric barrierdischarge

Fabrication of ultrafine Nd-Fe-B powder by a modified reduction-diffusion process

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Rare Metals 2006年第Z2期25卷 223-226页

作者： jang T.S. LEE D.H. CHOI C.j. SEO W.S. LEE y.H. Department of Electronic Materials Engineering Sunmoon University Korea Powder Materials Research Center Korea Institute of Machinery and Materials Korea Advanced Materials Analysis & Evaluation Center Korea Institute of Ceramic Engineering and Technology Korea

In order to obtain ultrafine Nd-Fe-B powder, a spray-dried precursor was treated by reduction-diffusion (R/D) process. And, unlike the conventional R/D process, calcium reduction that is a crucial step for the formation of Nd2Fe14B was performed without conglomerating the precursor with Ca powder. By adopting this modified process, it is possible to synthesize the hard magnetic Nd2Fe14B at the reaction temperature as low as 850 ℃. The average size of Nd2Fe14B particles that are uniformly distributed in the optimally treated powder was yers of Nd-rich phase. Typical magnetic properties of such powder without eliminating impurity CaO were iHc=～5.9 kOe, Br=～5.5 kG, and (BH)max=～6 MGOe.

关键词： NdFeB powder spray drying reduction-diffusion process Nd2Fe14B magnetic powder