Effect of Forging Type on the Deformation Heterogeneities in Multi‑Axial Diagonal Forged AA1100

Min‑Seong Kim,Sang‑Chul Kwon,Sun‑Tae Kim,Seong Lee,Hyo‑Tae Jeong,Shi‑Hoon Choi 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.3

The present study investigated the effects that different types of forging exert on the deformation heterogeneities developedin AA1100 during multi-axial diagonal forging. To measure the deformation heterogeneities of deformed workpieces, thevalues for hardness and Kernel average misorientation were measured at the center section following each forging process. Type-D forging that consists of diagonal forging and return-diagonal forging was relatively advantageous compared withType-P forging that includes plane forging and return-plane forging for minimizing the non-uniformity of deformationdeveloped in workpieces. The effective strain developed in a workpiece during the 2 types of forging was simulated using3-D FEA. FEA revealed that the positions and degrees of occurrence for soft and hard-zones in workpieces vary greatlydepending on the forging type. Type-D forging was relatively advantageous compared with Type-P forging for minimizingthe non-uniformity of effective strain developed in workpieces.

Crosslinked anion exchange membranes with primary diamine-based crosslinkers for vanadium redox flow battery application

Cha, Min Suc,Jeong, Hwan Yeop,Shin, Hee Young,Hong, Soo Hyun,Kim, Tae-Ho,Oh, Seong-Geun,Lee, Jang Yong,Hong, Young Taik Elsevier 2017 Journal of Power Sources Vol.363 No.-

<P><B>Abstract</B></P> <P>A series of polysulfone-based crosslinked anion exchange membranes (AEMs) with primary diamine-based crosslinkers has been prepared via simple a crosslinking process as low-cost and durable membranes for vanadium redox flow batteries (VRFBs). Chloromethylated polysulfone is used as a precursor polymer for crosslinked AEMs (CAPSU-x) with different degrees of crosslinking. Among the developed AEMs, CAPSU-2.5 shows outstanding dimensional stability and anion (Cl<SUP>−</SUP>, SO<SUB>4</SUB> <SUP>2−</SUP>, and OH<SUP>−</SUP>) conductivity. Moreover, CAPSU-2.5 exhibits much lower vanadium ion permeability (2.72 × 10<SUP>−8</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>) than Nafion 115 (2.88 × 10<SUP>−6</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>), which results in an excellent coulombic efficiency of 100%. The chemical and operational stabilities of the membranes have been investigated via ex situ soaking tests in 0.1 M VO<SUB>2</SUB> <SUP>+</SUP> solution and in situ operation tests for 100 cycles, respectively. The excellent chemical, physical, and electrochemical properties of the CAPSU-2.5 membrane make it suitable for use in VRFBs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The crosslinking between polymer chains are constructed by 4,4′-diaminobenzophenone. </LI> <LI> The crosslinked AEMs were fabricated by commercial polysulfone (PSU; Udel<SUP>®</SUP> P-3500). </LI> <LI> The crosslinked AEM based on PSU indicated good chemical and dimensional stability. </LI> <LI> The performance of crosslinked AEM showed high EE (86%) with high capacity retention. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

친환경 계면활성제 Potassium Cocoyl Glycinate (PCG)가 알칼리 전처리된 백합나무의 효소 당화에 미치는 영향

민병철(Byeong-Cheol Min),정수빈(Subin Jeong),송우용(Woo-Yong Song),성현아(Hyun-A Seong),신수정(Soo-Jeong Shin) 한국펄프·종이공학회 2018 펄프.종이기술 Vol.50 No.1

Potassium cocoyl glycinate (PCG) as a green surfactant was used to evaluate the possibility to substitute petrochemical surfactants for productivity improvement of enzymatic hydrolysis. Yellow poplar (Liriodendron tulipifera L. ) was subjected to NaOH (0.1%, 1.0% and 10.0%) pretreatment at 121°C for 60 min. Pretreated substrate (5.0% w/v) was hydrolyzed by enzyme under the variety PCG concentrations up to 0.3%. The optimum dose of PCG was around 0.03% at which it resulted in the highest total sugar production for all pretreatment conditions. The total sugar production of pretreated yellow poplar with 0.1%, 1.0% and 10.0% of NaOH increased from 2.3, 20.1, 20.8 g/L to 7.7, 25.7, 31.8 g/L under 0.03% of PCG concentration at 72 h hydrolysis. The effect of PCG to improve enzymatic hydrolysis was significantly promising as compared to other researches applying surfactants for hydrolysis. In conclusion, application of PCG was a promising alternative to replace petrochemical surfactants in enzymatic hydrolysis processes due to the high sugar production and positive influence on the ecosystem.

Purification and Characterization of Helicobacter pylori ${\gamma}$-Glutamyltranspeptidase

Song, Jae-Young,Choi, Yeo-Jeong,Kim, Jeong-Min,Kim, Yoo-Ree,Jo, Jin-Seong,Park, Jin-Sik,Park, Hee-Jin,Song, Yun-Gyu,Lee, Kon-Ho,Kang, Hyung-Lyun,Baik, Seung-Chul,Youn, Hee-Shang,Cho, Myung-Je,Rhee, Kw The Korean Society for Microbiology 2011 Journal of Bacteriology and Virology Vol.41 No.4

Gamma-glutamyltranspeptidase (GGT) was purified to electrophoretic homogeneity from the cell extract of H. pylori. The purified enzyme consisted of heavy and light subunits with molecular weights of 38 kDa and 21 kDa, respectively. N-terminal amino acid sequence of heavy and light subunits revealed that H. pylori GGT was processed into 3 parts for a signal peptide of 27 amino acid residues, a heavy subunit of 352 residues, and a light subunit of 188 residues during translation. The reaction rate for hydrolysis of ${\gamma}$-GpNA was 84.4 ${\mu}mol/min$ per milligram of protein, and that for the ${\gamma}$-glutamyl transfer from ${\gamma}$-GpNA to gly-gly was 23.8 ${\mu}mol/min$ per milligram of protein. The apparent Km values of H. pylori GGT for ${\gamma}$-glutamyl compounds were on the order of $10^{-3}$ to $10^{-4}$ M and those for acceptor peptides and amino acids were on the order of $10^{-1}$ to $10^{-2}$ M. The GGT protein kept approximately 80% of the initial enzymatic activity on incubation at $60^{\circ}C$ for 15 min. The optimum temperature and pH for reactions of both hydrolysis and transpeptidation were $40^{\circ}C$ and 9.0, respectively. The transpeptidation and hydrolysis reactions catalyzed by H. pylori GGT were strongly inhibited by L-Gln and moderately inhibited by L-Ala, L-Ser, ${\beta}$-chloro-L-Ala, and L-Glu. These results demonstrated that the biochemical properties of H. pylori GGT are different from those of other bacterial GGTs. Further, H. pylori GGT might degrade glutathione in the gastric mucous layer of humans if the enzyme could be secreted in the bacterial niches.

혈액 투석 환자에서 중심정맥 협착에 대한 스텐트 삽입술 : Wallstent Placement

임대승,노상필,이유선,정승현,김보영,이정우,강정아,김정희,이민수,정준용,최시완,정진옥,성인환,이강욱,신영태 충남대학교 의과대학 의학연구소 2002 충남의대잡지 Vol.29 No.1

Stenosis of central vein is a common complication arising after percutaneous subclavian vein catheter insertion performed for temporary vascular access in chronic renal failure patients undergoing hemodialysis. There are several treatment methods for the condition like percutaneous angioplasty(PTA), stent insertion, and surgery, but recent trend is toward PTA and stents. Among the patients diagnosed with chronic renal failure from March 1993 to May 2002 and undergoing hemodialysis through AV fistula, the 14 Patients in whom central vein stenosis arose were selected for the study. A total of 28 percutaneous interventions(5 PTA and 23 stent placement) were performed, and restenosis rate and the time taken till the restenosis in de novo lesions and instant lesions were compared. All 28 cases were operated successfully. The 14 cases that received both anigioplasty and stent placement initially. (de novo lesion : 14 cases), Among the 10 cases with de novo lesion that followed up more than 1 year, 3 cases are currently undergoing hemodialysis without restenosis, and the remaining 7 cases have recurred stenosis with the mean time to restenosis of 10.9 months. In the 7 cases in whom stenosis recurred, 11 interventions were done(instent lesion: 11 cases). 4 of these were using only ballon angioplasty with 100% restenosis rate and the mean time of 3 months until restenosis. The remaining 7 cases were using both balloon angioplasty and stent placement, also with 100% restenosis rate but with the mean time of 12 months until restenosis, which was later than the group receiving only balloon angioplasty. In treating the patients with central vein stenosis, stent placement seems to be more advantageous over PTA in terms of restenosis rate and the mean duration of patency. In the case of instent lesion, inserting the stent for the second time after stenosis recurred lengthened the duration of patency compared to performing balloon angioplasty alone.

단신 : 실리콘의 염소화반응에 의한 사염화규소 제조

박균영 ( Kyun Young Park ),이미선 ( Mi Sun Lee ),김민철 ( Min Cheol Kim ),이찬희 ( Chan Hee Lee ),박회경 ( Hoey Kyung Park ),강태원 ( Tae Won Kang ),정해성 ( Hae Seong Jeong ),한경아 ( Kyoung Ah Han ),허원회 ( Weon Hoe Huh ),유지 한국화학공학회 2013 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.51 No.3

직경 25 mm의 파이렉스 튜브 내에서 실리콘의 유동층 염소화 반응이 수행되었다. 반응기에 공급되는 질소 유량0.8~1.0 L/min, 염소 유량 0.2 L/min, 반응온도 450℃, SiCl4 응축기의 냉매온도는 -5℃로 설정하였다. 반응기에 도입되는 가스 내 염소의 몰분율이 증가하면 SiCl4의 수율이 증가하였다. 반응가스 중 염소의 몰분율 0.2의 조건에서 SiCl4의 수율은 28% 이었다. 염소의 몰분율 증가는 반응열 상승에 의해 반응온도 상승을 가져옴으로써 안전을 고려하여 염소의 몰분율을 0.2 이상으로 올리지 못했다. 실리콘의 유동층 염소화 반응에 의한 사염화실리콘의 제조 가능성이 입증되 었으며, 향후 보다 가혹한 조건에서의 실용화 연구를 위한 기초로 활용될 수 있을 것으로 기대된다. The chlorination of a metallurgical-grade silicon was carried out in a fluidized bed reactor, 25 mm in diameter. The flow rate of the chlorine admitted into the reactor was 0.2 L/min and that of the carrier nitrogen was 0.8~1.0 L/ min. The reactor temperature was maintained at 450℃ and the temperature of the coolant at the SiCl4 condenser was at -5℃. The SiCl4 yield increased with increasing the mole fraction of chlorine in the feed gas, exhibiting 28% at the mole fraction of 0.2. Further increase of the chlorine mole fraction was not attempted in a worry that the reactor might be failed due to the high exothermicity of the reaction. The production of SiCl4 from silicon by fluidized bed chlorination was demonstrated on a laboratory scale, which is a stepping stone for future studies under more severe conditions toward industrial application.

흰주 전정핵신경 칼륨 전류

정한성,차민정,김태선,박종성 全南大醫大 2001 전남의대학술지 Vol.37 No.2

腎皮質 電氣 燒灼法에 의한 白鼠 慢性 腎不全症 모델 誘導에 관한 硏究

정민수,김성숙,이강욱,신영태 충남대학교 의과대학 지역사회의학연구소 1993 충남의대잡지 Vol.20 No.2

An animal model with experimental uremia is an a important research tool for the study of sequence of pathological events taking place in uremic syndrome. A number of animal models and methods for the induction of chronic uremia have been published. The present study is designed to estabilish usefullness of a new method for the induction of chronic uremia in the rat. This method consist of unilateral destruction of most of the renal cortex by burns and contralateral nephrectomy. To investigate the results of massive renal ablation by this method, we measured serially blood pressure, body weight, BUN, serum creatinine, creatinine clearance, rate and examined renal histology. The results were as follows : 1) Surgical mortality rate was 5% and postoperative mortality of experimental group was 30.8% during 15 weeks of postoperative period. 2) Blood pressure of experimental group was significantly higher than control group after renal ablation(p<0.01). 3) Experimental group showed lower body weight gain than control group(p<0.01). 4) BUN and serum creatinine values increased continuously after renal ablation. However, those of control group were not changed. 5) Creatinine clearence rate of experimental group decreased significantly after renal ablation(p<0.01). 6) Weight of remnant kidney in experimental group was significantly higher than left kidney of control group(p<0.01). 7) Histologically, focal and segmental glomerular sclerosis, mesangeal proliferation, interstitial fibrosis and tubular atrophy appeared in the kidney of most experimental group 15 weeks after renal ablation. In conclusion, experimental rat group shows remarkable uremic appearance 7-11 weeks after renal ablation. This suggests that the unilateral renal cortical electrocoagulation and contralateral nephrectomy was a useful method for inducing experimental CRF rat model.

젊은 성인에서 신체 만족도에 따른 문제해결양식, 대인관계문제와 우울증상과 자살사고와의 관련성

차승민,김태성,강문희,권명진,김정란,왕성근,지익성 대한생물치료정신의학회 2011 생물치료정신의학 Vol.17 No.2

Objectives:The aim of this study was to evaluate that problem solving styles, interpersonal problems, depression and suicidal ideation according to body image satisfaction. Methods:One hundred and nineteen young healthy normal subjects filled out administered the Body Dysmorphic Disorder Examination-Self Report (Korean version of BDDE-SR K-BDDE-SR), Problem Solving Style Scale(Korean version PSS), Korean Inventory of Interpersonal Problem(KIIP), Korean version of the Depression Anxiety Stress Scale(KDASS-21), Korean version of Beck Scale for Suicidal Ideation(Korean version SSI) and Korean version of Reynolds Suicidal Ideation Questionnaire(Korean version SIQ) for a month. Results:Out of the 119 subjects, 39%(N=46) was male and 61%(N=73) was female. In high K-BDDE-SR group (higher than 67), helplessness was significantly higher than low K-BDDE-SR group(lower than 67), and problem-solving confidence, creative style, approach style were significantly lower than low K-BDDE-SR group. Also, Higher level of all KIIP factors in High K-BDDE-SR group was significantly differ than low K-BDDE-SR group. In High K-BDDE-SR group, K-DASS-21, SSI, and SIQ were significantly higher than low K-BDDE-SR group. Using multiple regression analysis contributing variance toward the total factor score of K-BDDE-SR of participants were K-DASS-21 and SIQ. Conclusion:Our results indicates that high tendency of dissatisfied body images have differences in helplessness, problem-solving confidence, approach style, interpersonal problems, depression and suicidal ideation compared to low tendency of dissatisfied body images. It is necessary to study body dysmorphic disorder patients group in the future.

외안각 절제술과 경결막 절개에 의한 안와 접근법

정종철,김성범,서지훈,송민석,전창훈,최세훈,김현민 대한악안면성형재건외과학회 2002 Maxillofacial Plastic Reconstructive Surgery Vol.24 No.4

Various surgical approaches to the orbits have been used. But the transconjunctival approach, also called the inferior fornix incision, provides adequate access to the orbital floor with esthetic results. Additionally, transconjunctival approach with lateral canthotomy allows more wide surgical field and good access to the orbital area. Generally, preseptal approach is more used rather than postseptal approach in the transconjunctival incision for the prevention of fat herniation during surgery. There are some complications in transconjunctival approaches but these complications can be prevented with careful surgical techniques. We report clinical results in 12 patients who were treated by preseptal transconjunctival incision with lateral canthotomoy for the treatment of orbital trauma. We were satisfied with this technique for reduction and reconstruction of the orbital trauma and we could also observe relatively good esthetic results.