수소버스용 내압용기 복합재의 열적환경에 따른 기계적 물성 연구

양현석 ( Hyunseok Yang ),정우철 ( Woo-chul Jung ),신광복 ( Kwang Bok Shin ),공만식 ( Man-sik Kong ) 한국복합재료학회 2022 Composites research Vol.35 No.6

수소가스용 압력용기의 안전성 평가를 위해 다양한 내구성 시험이 요구된다. 고온 정압 시험은 고압(875 bar) 하에 고온(85oC 이상)에서 장시간(1,000시간) 유지하여 수소 용기의 내구성을 시험하는 방법이며 승용차용 용기에 한정되어 있다. 하지만 대용량 수소버스용 용기와 관련된 고온 정압 시험의 국제 기준은 논의 초기 단계이며, 시험의 효율성 및 신뢰성 측면에서 가속시험 기준 제시 등의 현실적 보완이 필요하다. 본 연구에서는 수소버스용 내압용기의 고온 정압 시험 기준을 정립하기 위해 열적환경에 노출된 내압용기 복합재의 기계적 물성평가를 진행하였다. 복합재의 인장강도는 수지의 유리전이온도에 가까워질수록 수지의 열화로 인해 강도가 감소한다. 또한 장시간 유지 시 수지의 후경화로 인해 인장강도의 재상승을 확인할 수 있었다. 따라서 대용량 수소버스용 압력용기의 고온 정압 시험은 탄소섬유 복합재의 에폭시 수지 물성을 바탕으로 시험 조건을 설정해야 한다. In this study, the mechanical properties of the pressure vessel composite exposed to the thermal environment were evaluated to establish the standard for high temperature static pressure test of the pressure vessel for hydrogen bus. As the tensile strength of the composite material approaches the glass transition temperature of the epoxy resin, the strength decreases due to the deterioration of the epoxy resin. In addition, it was confirmed that the tensile strength increased again due to the post-curing of the epoxy resin during long-term exposure. Therefore, the accelerated stress rupture test conditions of the pressure vessel for the hydrogen bus should be set based on the epoxy resin properties of the carbon fiber composite material.

A 24-Month Effects of Methylphenidate Use on Growth in Children and Adolescents With Attention Deficit Hyperactivity Disorder

Lee Yoojeong,Kong Nayeong,Koo San,Bai Dai Seg,Kim Hee jin,Jeong Hyunseok,Seo Wan Seok 대한신경정신의학회 2022 PSYCHIATRY INVESTIGATION Vol.19 No.3

Objective The primary objective of this study was to investigate the effect of methylphenidate (MPH) on height, weight, and body mass index (BMI) in drug-naive children and adolescents with attention deficit hyperactivity disorder (ADHD) over 24 months. The secondary objective was to investigate whether the age of MPH initiation and sex act as risk factors for growth retardation.Methods A total of 82 patients with ADHD were included. Weight, height, and BMI were measured at baseline and every 6 months up to 24 months. Weight, height, and BMI data were converted to z-scores and analyzed using two-way repeated-measures ANOVA and multiple linear regression.Results The z-score of height, weight and BMI decreased from the baseline values. The z-scores of height were at baseline 0.002; 6 months -0.100; 12 months -0.159; 18 months -0.159; 24 months -0.186. The z-scores of weight were at baseline 0.104; 6 months -0.155; 12 months -0.256; 18 months -0.278; 24 months -0.301. Here were no age and sex differences of height, weight, and BMI.Conclusion The use of MPH was associated with attenuation of weight and height gain rates in children and adolescents with ADHD.

A study on electropolishing of NiTi shape memory alloy wire for improvement of surface roughness and corrosion resistance

Deokhyun HAN,Hyunseok YANG,Chul-Han SONG,Man-Sik KONG,Shingoo HUR 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

주조용 TiAl 합금의 조직 미세화를 위한 반복열처리 공정 조건에 관한 연구

공만식 ( Man-sik Kong ),양현석 ( Hyunseok Yang ) 한국열처리공학회 2019 熱處理工學會誌 Vol.32 No.5

For expanding the applications and workability of TiAl alloy, elongation is very important property. Fine microstructure is needed for elongation and physical properties of TiAl alloys. In this study, The effects of cyclic heat treatment process for fine microstructure of Ti-46Al-Nb-W-Cr-Si-C alloy, which was made by VAR (vacuum arc remelting) and VIM(vacuum induction melting) centrifugal casting process, was investigated. Cycle heat treatment process was very effective for recrystallization of this TiAl system, which has microstructure size of 50~100 μm through pre-heat treatment, cyclic heat treatment in α+γ phase region and solution heat treatment respectively. Refined grain size was finally confirmed by photos of optical microscope and scanning electron microscope.

폐(廢) 냉장고(冷藏庫) 재활용(再活用) 현황(現況)과 기술(技術) 전망(展望)

양현석,김건홍,공만식,박기진,이광원,김보생,Yang, Hyunseok,Kim, Geon-Hong,Kong, Man-Sik,Park, Kiejin,Lee, Gwang Weon,Kim, Bo Saeng 한국자원리싸이클링학회 2013 資源 리싸이클링 Vol.22 No.4

냉장고는 폐 전기전자제품(WEEE)에서 가장 많은 양이 처리되고 있는 품목이며 또한 가장 재활용이 복잡한 공정이다. 이는 가전제품 중 부피와 중량이 가장 크며 철, 비철금속, 플라스틱(PP, PS, ABS)등으로 이루어진 다양한 부품과 소재를 사용하고 있기 때문이다. 특히 최근에는 대용량 양문형 냉장고나 스탠드형 김치냉장고 등의 새로운 모델 출시와 더불어 다양한 혼합 재질의 사용으로 인해 폐 냉장고 재활용 공정의 어려움이 더욱 증가되고 있다. 뿐만 아니라 국내외 WEEE 재활용 관련 입법의 도입으로 폐 냉장고의 재활용 및 재자원화는 필수이고 관련 자원순환기술개발은 국가 기술경쟁력의 강화 및 국제 환경규제 대응 측면에서도 매우 중요하다고 할 수 있다. 따라서 현재 우리나라의 폐 냉장고 재활용 처리 및 기술개발 현황을 분석하고 선진국의 재활용 기술을 비교 분석하고자 한다. Waste refrigerator is the most large amount of item being recycled and the recycling process is the most complicated in WEEE (Waste Electrical and Electronic Equipment) because refrigerator is biggest product and consists of various parts and materials such as ferrous, non-ferrous, and plastics. Recently, recycling process of waste refrigerator has been being more complex since large capacity 2 door refrigerators and standing Kimchi refrigerators with various material are distributed on custom market. In addition, recycling of valuable resource from waste refrigerator is mandatory by WEEEs recycling legislation; therefore, high efficiency recycling enough for economic and environment-friendly recovery of valuable resource through present technical situation analysis and comparison of recycling technologies of waste refrigerator with advanced country.

Immunomodulatory Effects of Dioscoreae Rhizome Against Inflammation through Suppressed Production of Cytokines Via Inhibition of the NF-${\kappa}B$ Pathway

Kim, Seulah,Shin, Seulmee,Hyun, Bobae,Kong, Hyunseok,Han, Shinha,Lee, Aeri,Lee, Seungjeong,Kim, Kyungjae The Korean Association of Immunobiologists 2012 Immune Network Vol.12 No.5

Dioscoreae Rhizome (DR) has been used in traditional medicine to treat numerous diseases and is reported to have anti-diabetes and anti-tumor activities. To identify a bioactive traditional medicine with anti-inflammatory activity of a water extract of DR (EDR), we determined the mRNA and protein levels of proinflammatory cytokines in macrophages through RT-PCR and western blot analysis and performed a FACS analysis for measuring surface molecules. EDR dose-dependently decreased the production of NO and pro-inflammatory cytokines such as IL-$1{\beta}$, IL-6, TNF-${\alpha}$, and $PGE_2$, as well as mRNA levels of iNOS, COX-2, and pro-inflammatory cytokines, as determined by western blot and RT-PCR analysis, respectively. The expression of co-stimulatory molecules such as B7-1 and B7-2 was also reduced by EDR. Furthermore, activation of the nuclear transcription factor, NF-${\kappa}B$, but not that of IL-4 and IL-10, in macrophages was inhibited by EDR. These results show that EDR decreased pro-inflammatory cytokines via inhibition of NF-${\kappa}B$-dependent inflammatory protein level, suggesting that EDR could be a useful immunomodulatory agent for treating immunological diseases.

Studies on Production of High Fat Diet Induced Obesity C57BL/6NCrjBgi Mice

Chungtaek Han,Sanghoon Lee,Seungbin Lim,Hyunseok Kong,Soohyeon Kim,Sangkyun Lee,Jaejin Chang 한국실험동물학회 2006 Laboratory Animal Research Vol.22 No.3

To save researcher's animal room space, time and expense, we developed a standard protocol for production of diet induced obesity C57BL/6NCrjBgi mice. In this study, we evaluated general clinical signs, weekly body weight changes, weekly food intake, organ weights and glucose tolerance on male C57BL/6NCrjBgi mice fed high (D12451, Rodent Diet with 45 ㎉% fat, Research Diets Inc., New Brunswick, NJ; D-45 Group) and low (D12450B, Rodent Diet with 10 ㎉% fat; D-10 Group) fat diets for 16 weeks. The mean body weight of D-45 Group had significantly increased compared to D-10 Group as early as 1 week after initiation of diet. Food intake was not significantly different between two groups, but caloric intake and food efficiency ratio were significantly increased in D-45 Group. Absolute organ weights of spleen, liver, pancreas and kidneys in D-45 Group were significantly increased compared to D-10 Group. The significantly increased fat deposit in epididymal and perirenal area was found in D-45 Group. In glucose tolerance test, D-45 Group mice had glucose intolerance compared to D-10 Group mice. In summary, the first characterization data of C57BL/6NCrjBgi mice fed high fat diet for 16 weeks is very similar to the most frequently used C57BL/6J diet induced obesity (DIO) mouse model of Jackson Laboratory, USA.

Immunomodulatory Effects of Dioscoreae Rhizome Against Inflammation through Suppressed Production of Cytokines Via Inhibition of the NF-κB Pathway

Kim, Seulah,Shin, Seulmee,Hyun, Bobae,Kong, Hyunseok,Han, Shinha,Lee, Aeri,Lee, Seungjeong,Kim, Kyungjae 대한면역학회 2012 Immune Network Vol.12 No.5

Dioscoreae Rhizome (DR) has been used in traditional medicine to treat numerous diseases and is reported to have anti-diabetes and anti-tumor activities. To identify a bioactive traditional medicine with anti-inflammatory activity of a water extract of DR (EDR), we determined the mRNA and protein levels of proinflammatory cytokines in macrophages through RT-PCR and western blot analysis and performed a FACS analysis for measuring surface molecules. EDR dose-dependently decreased the production of NO and pro-inflammatory cytokines such as IL-1β, IL-6, TNF-α, and PGE₂, as well as mRNA levels of iNOS, COX-2, and pro-inflammatory cytokines, as determined by western blot and RT-PCR analysis, respectively. The expression of co-stimulatory molecules such as B7-1 and B7-2 was also reduced by EDR. Furthermore, activation of the nuclear transcription factor, NF-κB , but not that of IL-4 and IL-10, in macrophages was inhibited by EDR. These results show that EDR decreased pro-inflammatory cytokines via inhibition of NF-κB -dependent inflammatory protein level, suggesting that EDR could be a useful immunomodulatory agent for treating immunological diseases.

Downregulation of IL-18 Expression in the Gut by Metformin-induced Gut Microbiota Modulation

Heetae Lee,Jiyeon Kim,Jinho An,Sungwon Lee,Dohyun Choi,Hyunseok Kong,Youngcheon Song,Il Ho Park,Chong-Kil Lee,Kyungjae Kim 대한면역학회 2019 Immune Network Vol.19 No.4

Amelioration of Benign Prostatic Hyperplasia by Costunolide and Dehydrocostus Lactone in Wistar Rats

Choi Dohyun,Kim Jiyeon,An Jinho,Hong Seonhwa,Song Youngcheon,Kong Hyunseok 대한남성과학회 2021 The World Journal of Men's Health Vol.39 No.2

Purpose: Sesquiterpene lactones, which are found in plants of the Asteraceae family, contain costunolide (CO) and dehydrocostus lactone (DCL) as indicator material. CO, in particular, has been reported to possess varied pharmacological activity, including anti-inflammatory, antibacterial, and antioxidant effects. This study was designed to characterize the effects of CO and DCL on benign prostate hyperplasia (BPH). Materials and Methods: Rats were injected subcutaneously daily for 8 weeks with 5 mg/kg testosterone to induce prostatic hyperplasia. Wistar rats were randomly divided into 5 groups of 10 animals each and received the following treatment: I. Normal control group; II. BPH-induced group; III. CO group (0.075 mg/kg); IV. DCL group (0.075 mg/kg); and V. Finasteride group (0.8 mg/kg). After treatment, changes in prostate weight and serum biochemical indices, serum dihydrotestosterone level, and mRNA levels of BCL2 were measured and histological examinations performed. Results: Absolute and relative prostate weight in the indicator material treated groups, as well as prostate volume, decreased compared to those in the disease-induced group. Epithelial cell thickness increased significantly in the disease-induced group, with a significant decrease being observed in the CO group. The level of the anti-apoptotic protein BCL2 (B-cell lymphoma 2) tended to decrease to a greater extent in the DCL group than in the disease-induced group. Conclusions: In this study, we confirmed that the indicator materials (CO and DCL) can help suppress the development of BPH.