Formulation Prediction for Young's Modulus of Poly(dimethylsiloxane) by Spectroscopic Methods

Cho Han Saem,Moon Heh‐Young,Lee Heung Soon,Kim Yong Tae,Jeoung Sae Chae 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.9

In this work, we refer to the fraction of hydrides and vinyl groups consumed in cross-linking reaction as a variation of the properties of poly(dimethylsiloxane) (PDMS) with varying the formulation of a curing agent from 3.2 wt % to 50 wt %. Young’s modulus, density, and refractive indices of PDMS were observed to have a maxima at a formulation of about 10 wt % of cross linker. The intensity of the Raman band for the Si H stretching mode in cross-linker is almost zero if the cross-linking agent is less than 10 wt %, but it is linearly increasing with increasing the content of cross-linker. The dependence of the elastic modulus on the formulation could be explained in terms of the fraction of cross-linked network. The analytical framework proposed in this work could be used for optimizing the formulation of PDMS and hence its properties can be tailored for specific applications.

고분자형 자외선 안정제를 함유한 SBR과 NR의 UV 노화 거동에 관한 연구

남경태 ( Kyoung Tae Nam ),홍창국 ( Chang Kook Hong ),채규호 ( Kyu Ho Chae ),강신영 ( Shin Young Kaang ) 한국고무학회 2006 엘라스토머 및 콤포지트 Vol.41 No.3

본 연구에서는 고분자형 자외선 안정제 DGEBA-HALS의 광분해 억제 효과를 평가하기 위해 SBR과 NR 고무를 사용하여 광안정제 첨가에 따른 UV 조사 영향을 고찰하였다. 이를 위해 광안정제를 첨가하지 않은 배합고무, 사용화된 광안정제인 Cyabsorb UV-3529를 첨가한 배합고무, 그리고 고분자형 DGEBA-HALS를 첨가한 배합고무의 영율, 인장장고, blow-off 변형, 가교밀도 측정을 통한 시편의 물리적 특성변화 등을 관찰하였다. UV 조사 후 모든 시편에서 영율이 증가하였으며 인장강도는 광안정제를 첨가한 시편이 첨가하지 않은 시편보다 우수했다. 특히 NR의 경우 DGEBA-HALS 첨가 시 인장강도가 향상되었다. Blow-off 변형 실험결과도 영율 실험 결과와 비슷하였다. UV-vis transmissinon spectra를 통한 SBR 배합고무의 투과도를 조사한 결과 광안정제를 첨가함으로써 약 4%의 향상된 투과도를 보였다. Cyabsorb UV-3529와 DGEBA-HALS의 첨가는 비슷한 경향의 투과도를 나타내었다. SEM을 통해 시편의 표면을 관찰한 결과 광안정제를 첨가함으로써 UV 조사에 의한 균열의 크기가 작아짐을 알 수 있었고, 특히 DGEBA-HALS는 상용화된 Cyabsorb UV-3529 보다 더 좋은 광분해 안정효과를 갖는 것을 확인할 수 있었다. The retardation effects of a new polymeric UV stabilizer, DGEBA-HALS, on the UV degradation of SBR and NR were investigated in this study. The UV degradation behaviors of three different rubber compounds, without any photostabilizer and with commercial Cyabsorb UV-3529 and DGEBA-HALS, were compared. Also, the physical characteristics such as Young`s modulus, tensile strength, blow-off deformation and crosslink density were examined. The Young`s modulus was increased by UV irradiation for all samples, and the tensile strength, after UV irradiation, of the compound with UV stabilizer was better than that of the compound without stabilizer. Especially, the tensile strength of UV irradiated NR was improved by adding DGEBA-HALS. The results of blow-off deformation were in accord with those of Young`s modulus. The degree of transmission of SBR compounds obtained from UV-vis transmission spectra was improved about 4% by adding the UV stabilizer. Commercial Cyabsorb UV-3529 and DGEBA-HALS showed similar trends of transmission. The SEM photographs of SBR surface showed that the size of cracks created by UV irradiation became smaller by adding UV stabilizer. In particular, it is observed that the stabilization effect of DGEBA-HALS was better than that of commercial Cyabsorb UV-3529.

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

21가지 장미꽃 품종의 페놀성 화합물 함량 및 항산화 활성

조연재(Yeon Jae Jo),서정현(Jeong Hyun Seo),홍채영(Chae Young Hong),김성태(Seung Tae Kim),최은경(Ehn-Kyoung Choi),김윤배(Yun-Bae Kim),이준수(Junsoo Lee),정헌상(Heon Sang Jeong) 한국식품영양과학회 2021 한국식품영양과학회지 Vol.50 No.4

본 연구는 21품종의 장미꽃에 대한 식품 및 화장품 원료로 사용 가능성을 살펴보기 위해 페놀성 화합물과 항산화 활성을 평가하였다. 총 폴리페놀, 총 플라보노이드 및 타닌 함량은 러버샤이 품종에서 각각 379.70 mg GAE/extract g, 50.10 mg CE/extract g 및 339.44 mg TAE/extract g으로 높게 나타났으며, 칠백리 품종에서 각각 107.25 mg GAE/extract g, 9.46 mg CE/extract g 및 36.31 mg TAE/extract g으로 낮았다. 페놀산 함량은 총 폴리페놀 함량과 유사한 결과를 보였으며, 러버샤이 품종에서 27.40 mg/extract g으로 높았다. 안토시아닌은 대부분 cyanidin-3,5-diglucoside로 확인되었으며 총 안토시아닌 함량은 유니나 품종에서 8.80 mg/extract g으로 가장 높았다. ABTS 및 DPPH 라디칼 소거 활성은 각각 428.10 및 419.59 mg AAE/extract g로 러버샤이 품종에서 가장 높았으며, 항산화 활성과 페놀 화합물의 함량과 높은 양의 상관관계를 보였다. 이러한 결과는 러버샤이와 같은 항산화 활성이 뛰어난 품종들이 관상 목적뿐만 아니라 높은 기능성을 가진 식품 및 화장품의 원료로 사용 가능성이 있다고 판단된다. This study evaluated the functional components and antioxidant activities of 21 different rose flower extracts, to confirm their value as a food and cosmetics ingredient. The highest values of total polyphenol, flavonoid and tannin contents (379.70±1.64 mg GAE/extract g, 50.10±0.76 mg CE/extract g, and 339.44±1.20 mg TAE/extract g, respectively) were obtained in Lover Shy. The proanthocyanidin content ranged from 61.88 mg CE/extract g in the Unina cultivar to 5.34±0.13 mg CE/extract g in the Aileen cultivar. The phenolic acid content obtained was highest in the Lover Shy cultivar (27.40±0.26 mg/extract g), whereas highest levels of anthocyanin (8.83±0.03 mg/extract g) were obtained in the Unina cultivar. High ABTS and DPPH radical scavenging activities were determined in the Lover Shy cultivar (428.10±0.29 and 419.59±3.12 mg AAE/extract g, respectively). Taken together, these results indicate that the antioxidant activity and functional components of Lover Shy cultivar are superior, and this extract can potentially be applied as a food and cosmetic ingredient.

Dump 소각기에서 CCl_(4) 분해에 대한 수치해석

채종성,엄태인,전영남,문승현 한밭대학교 생산융합기술연구소 2004 생산기반기술연구소 논문집 Vol.4 No.1

A major source of the hazardous waste generated is from chemical industries producing plastics, herbicides, pesticides and chlorinated solvents. All of these processes produce a class of hazardous waste termed the chlorinated hydrocarbons (CHCs), either directly or from undesirable side reactions. In this study, the destruction characteristics of hazardous waste through incineration is investigated by the development of a reliable computer program. Especially a nonequilibrium combustion model was used to describe the effect of the chemical kinetics due to the flame inhibition characteristics of CCl_(4) which was used as the surrogate of hazardous waste.

이트리아 첨가 붕규산염 유리로 제조한 알루미나-유리 복합체의 강도 평가

채민수,배태성,이주형,원대희,진영철 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.1

This study was performed to investigate the strength of dental alumina-glass composites. Four different brosilicacte glasses containing 1, 3, 6, 9 mol% Y₂O³ were prepared. Alumina compacts were prepared by pressing 150㎏/㎠ and sintering at 1100℃ for 2 hours. Dense composites were made by infiltrating partially sintered alumina with at 1200℃ for 6 hours. The obtained results were summarized as follows: 1. With increasing the amount of Y₂O₃ the peak of exothermic heat and softening point were shifted to the higher temperature. 2. Borosilicate glasses showed the coefficient of thermal expansion in the range of 6.36 to 6.56×10-6/℃. 3. The maximum biaxial strength of 385.7±34.4MPa was obtained with an addition of 6mol% Y₂O₃. 4. The observation of fracture surfaces showed the crack deflection and crack bridging and that appeared to be the principal strengthening mechanism in the alumina-glass composites.

형질전환돼지를 이용한 이종장기이식(xenotransplantation)과 돼지바이러스의 이종감염 잠재성 : A Review

채미경,김지영,김명철,박창식,김태용,전무형 충남대학교 생물공학연구소 2003 생물공학연구지 Vol.9 No.1

Recent advances in xenotransplantation technology as a therapeutic approach have the potential to benefit human health. Despite the greater immunological barrier, pigs are favored over primates as a source of transplant tissue for a variety of practical, ethical and safety reasons. The pigs are easy to breed and economic to produce, and the physiology and the size of porcine organs are similar to those in humans. However, It is important to recognize that xenotransplantation may put the human community at risk. Transplantation of porcine organs to human will allow microorganism present in the donor organs to bypass the normal defense mechanism of the recipient. Through xenogeneic infection, an agent that is non-pathognic in its natural host may become pathogenic in the recipient. The present article reviews the current knowledge regarding porcine viruses and their potential for xenogeneic transmission in humans upon xenotransplantation.

Si₃N₄-SiC Nanocomposite의 열전도도

채희백,정영석,이태기 순천향대학교 기초과학연구소 1997 순천향자연과학연구 논문집 Vol.3 No.2

Nano-sized SiC particles of 1, 10, 20 and 30 vol% were dispersed in a-Si₃N₄ matrix and hot-pressed under the condition of 30 MPa of N₂ at 1850℃. Thermal conductivity of Si₃N₄-SiC nanocomposite was measured between 300 K and 400 K. Si₃N₄-20 vol% SiC showed the lowest thermal conductivity. In growth Si₃N₄, SiC-nano particle could be a nucleation site and dispersion is maximized in the Si₃N₄-matrix when the vol% is 20. More than 20 vol% SiC, SiC particles are located on the Si₃N₄ boundaries. Thus, phonons are scattered well in Si₃N₄-20 vol% SiC with the dispersed SiC and thermal resistance(conductivity) is high(low). Similar behavior was reported in the electricl resistivity and fracture toughness.

자외선 불꽃 감지기의 개발에 관한 연구

채영무,박상태 충주대 2004 産業科學論文集 Vol.12 No.-

The technique that detects radiant energy from a flaming fire of fuels contained carbonaceous material can be applied to fast growing fires. This technique applied detectors are ultimately effective when early detecting fire alarm system is required or the smoke and heat detectors can not be applied. In Korea Fire regulation, a flame detector should be installed in case that the installation height is higher than 20 [m].Therefore it is really necessary that a flame detector has to be developed as soon as possible. The results of the research and development is as follows. With foundation technique of flame detector, ideal sensing element and stable circuit design, a trial UV flame detector is manufactured. UV radiant energy sensing device is developed through the modification and supplement of the structure and circuit. The R & D for the manufacture of an excellent flame detecting device is carried out with the establishment of technique for the mass production and the qualified manufacturing process.

형질전환돼지를 이용한 이종장기이식(xenotransplantation)과 돼지바이러스의 이종감염 잠재성

채미경,김지영,김명철,박창식,김태용,전무형 충남대학교 형질전환복제돼지연구센터 2004 논문집 Vol. No.8

Recent advances in xenotransplantation technology as a therapeutic approach have the potential to benefit human health. Despite the greater immunological barrier,pigs are favored over primates as a source of transplant tissue for a variety of practical,ethical and safety reasons. The pigs are easy to breed and economic to produce,and the physiology and the size of porcine organs are similar to those in humans. However,It is important to recognize that xcnotransplantation may put the human community at risk. Transplantation of porcine organs to human will allow microorganism present in the donor organs to bypass the normal defense mechanism of the recipient. Through xenogeneic infection, an agent that is non cingohtap-in its natural host may become pathogenic in the recipient. The present article reviews the current knowledge regarding porcine viruses and their potential for xenogeneic transmission in humans upon xenotransplantation.