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.

Projections of summertime ozone concentration over East Asia under multiple IPCC SRES emission scenarios

Lee, Jae-Bum,Cha, Jun-Seok,Hong, Sung-Chul,Choi, Jin-Young,Myoung, Ji-Su,Park, Rokjin J.,Woo, Jung-Hun,Ho, Changhoi,Han, Jin-Seok,Song, Chang-Keun Elsevier 2015 Atmospheric environment Vol.106 No.-

<P><B>Abstract</B></P> <P>We have developed the Integrated Climate and Air Quality Modeling System (ICAMS) through the one-way nesting of global–regional models to examine the changes in the surface ozone concentrations over East Asia under future climate scenarios. Model simulations have been conducted for the present period of 1996–2005 to evaluate the performance of ICAMS. The simulated surface ozone concentrations reproduced the observed monthly mean concentrations at sites in East Asia with high R<SUP>2</SUP> values (0.4–0.9), indicating a successful simulation to capture both spatial and temporal variability. We then performed several model simulations with the six IPCC SRES scenarios (A2, A1B, A1FI, A1T, B1, and B2) for the next three periods, 2016–2025 (the 2020s), 2046–2055 (the 2050s), and 2091–2100 (the 2090s). The model results show that the projected changes of the annual daily mean maximum eight-hour (DM8H) surface ozone concentrations in summertime for East Asia are in the range of 2–8 ppb, −3 to 8 ppb, and −7 to 9 ppb for the 2020s, the 2050s, and the 2090s, respectively, and are primarily determined based on the emission changes of NO<SUB>x</SUB> and NMVOC. The maximum increases in the annual DM8H surface ozone and high-ozone events occur in the 2020s for all scenarios except for A2, implying that the air quality over East Asia is likely to get worse in the near future period (the 2020s) than in the far future periods (the 2050s and the 2090s). The changes in the future environment based on IPCC SRES scenarios would also influence the change in the occurrences of high-concentrations events more greatly than that of the annual DM8H surface ozone concentrations. Sensitivity simulations show that the emissions increase is the key factor in determining future regional surface ozone concentrations in the case of a developing country, China, whereas a developed country, Japan would be influenced more greatly by effects of the regional climate change than the increase in emissions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Change in ozone level is determined by the combination of NO<SUB>x</SUB> and NMVOC emissions. </LI> <LI> Ozone level over East Asia would get worse in the near future (the 2020s) than far future. </LI> <LI> A high-concentration event generally increases and more frequently occurs in the future. </LI> <LI> Change in ozone air quality in a developing country depends more on emissions change. </LI> <LI> Change in ozone air quality in a developed country depends more on climate change. </LI> </UL> </P>

보조호르몬요법을 받는 여성 유방암 환자의 모발 변화와 치료 실태에 대한 기초 연구

이재경 ( Jae Kyung Lee ),김창현 ( Chang-hyun Kim ),홍동균 ( Dongkyun Hong ),정경은 ( Kyung Eun Jung ),서영준 ( Young-joon Seo ),김창덕 ( Chang-deok Kim ),이진선 ( Jin Sun Lee ),권인선 ( In Sun Kwon ),박상현 ( Sanghyun Park ),이영 대한피부과학회 2021 대한피부과학회지 Vol.59 No.7

Background: Hormone therapy, which includes tamoxifen and aromatase inhibitors, is the most common adjuvant therapy used for breast cancer. However, only a few studies have reported endocrine therapy induced alopecia. Objective: We investigated the effects of long-term adjuvant hormone therapy on hair in patients with breast cancer, in addition to patients’ concerns and current treatment for hair loss. Methods: Patients completed a questionnaire that included information on self-perceived hair changes after each adjuvant therapy session, distress, and current treatment for hair loss. Using a folliscope, we measured hair density and thickness in each patient and in healthy controls. Results: The study included 93 patients with breast cancer (mean age 51.9±9.8 years). The density and hair thickness were 106.36±21.85 hairs/cm2 and 0.07±0.01 mm in the patient group and 147.86±30.67 hairs/cm2 and 0.07±0.01 mm in the control group (n=98, mean age 52.10±8.40 years), respectively. The mean hair density was significantly lower in the patient group than in the control group; however, no statistically significant intergroup difference was observed in hair thickness. Among 76 patients who perceived hair changes after adjuvant therapy, 71.1% (n=54) were distressed with regard to hair changes. However, only 7.8% of the patients, including two who were treated by dermatologists, currently received treatment for hair changes. Conclusion: Dermatologists should be familiar with hair changes in patients with breast cancer and provide appropriate education to encourage patients to consult dermatologists for hair loss and thinning after breast cancer treatment. (Korean J Dermatol 2021;59(7):521∼526)

Carotenoids 식이와 알코올이 혈액학적 성분과 간조직에 미치는 영향에 관한 연구

조만희,김연선,이상한,우기민,장예진,김창세 순천향의학연구소 1999 Journal of Soonchunhyang Medical Science Vol.5 No.2

Alcohol is well known agent which can damage the human tissues such as liver via stimulating lipid peroxidation and storage, denaturation of macromolecules, and inhibiting protein metabolism. On the other hand, carotenoids in addition to vitamins A, C, E and lipoic acid, play important roles in protecting these oxidative damages as well as preventing the production of free radicals. This study was carried out to elucidate the precise effects of alcohol administration into rats on the antioxidative functions of dietary carotenoids and isolated β-carotene, and to find out any parameters to uncover more detailed biochemical mechanisms of these agents. For these purposes, two different approaches were performed: 1) examination of the changes in hematological parameters (e.g., total proteins, A/G ratio, ALT/AST et. al) and statistical correlations among inter- and intragroups, 2) examination of the histopathological changes by an electron microscope. The results were analyzed and summarized as following; (1) Carrot diet for one week caused a slight increase in albumin. A/G ratio and AST levels, and a slight decrease in ALT, ALP, BUN and uric acid levels. Two-week alcohol administration following carrot diet increased total proteins, albumin A/G ratio and BUN levels. However, both groups were shown to have little significant changes in cholesterol concentrations. (2) Cheese diet for one week caused a significant increase in total proteins, albumin, AST, ALP, uric acid and total cholesterol levels, and a significant decrease in A/G ratio and glucose concentrations. However, two-week β-carotene diet following cheese intake increased total proteins albumin, A/G ratio, BUN and total cholesterol levels, whereas AST, ALT, ALP and uric acid levels were decreased. (3) Alcohol administration for one week caused an increase in AST activities and a decrease in total proteins, albumin, ALT, ALP and BUN levels. A successive β-carotene diet following alcohol administration increased total proteins, albumin, ALT, ALP and BUN levels, whereas decreased AST and uric acid levels. However, there were not significant changes in A/G ratio, glucose and total cholesterol levels in both groups. (4) β-carotene diet for one week caused a slight increase in albumin, glucose, AST and uric acid levels, and a slight decrease in ALP and BUN levels. Two-weeks alcohol administration following β-carotene diet increased albumin, glucose, BUN and total cholesterol levels, whereas decreased AST, ALT, ALP and uric acid levels. (5) Although the pathological investigation on the liver did not reveal significant changes, cheese diet group (CH-BC/1-CH) was shown to have some lipid deposits. Some results were unexpected and different from typical hematological changes shown by other researchers. Nonetheless, these results strongly suggest that the liver damage or hepatism caused by alcohol intake affects many kinds of biochemical metabolisms, which results in significant changes in many hematological parameters. In addition, dietary carotenoid and isolated β-carotene were shown to have protective roles against the biochemical changes by alcohol intake.

Brain SPECT 영상의 Attenuation Correction 방법들에 대한 비교

조진우,김창호,나수경,이귀원,Jo, Jin U,Kim, Chang Ho,Na, Soo Kyung,Lee, Gui Won 대한핵의학기술학회 2012 핵의학 기술 Vol.16 No.2

이 연구의 목적은 Brain SPECT (Single Photon Emission Computed Tomography)의 Non-attenuation correction (AC-non) 영상에 대한 attenuation correction(AC) 방법 중 Chang's method와 CT based attenuation correction(AC-CT) 사이의 count를 비교하기 위함이다. phantom study는 증류수로 채워진 hoffman 3D phantom에 $^{99m}Tc$ 37Mbq을 투여하였고, patient study는 normal volunteer에 $^{99m}Tc$-HMPAO 750Mbq를 정맥주입하고 Siemens사의 Symbia T6로 Brain SPECT 영상을 획득하였고 뇌 정량 분석을 하였다. 각각의 방법들을 적용한 transverse image는 같은 위치에서 재구성 되었으며 각각 10, 20, 30번째 slice에서 6개의 region of interest(ROI)를 그려 AC-non 과 AC-CT 그리고 Chang's method의 count를 비교하였다. phantom study에서 AC-non, AC-CT, Chang's method의 각각 평균 count는 $4606.8{\pm}511.3$, $16794.6{\pm}2429.4$, $8752.6{\pm}896.5$이었으며 patient study에서 $5460.8{\pm}519.6$, $15320{\pm}1171.6$, $12795{\pm}1422.1$이었다. phantom study에서 AC-CT와 AC-non 사이의 비는 3.70이고 Chang's method와 AC-non 사이의 비는 1.92였으며 patient study에서는 각각 2.85, 2.38이었다. 우리는 이 연구를 통하여 AC-CT가 Chang's method보다 더 높은 AC을 해준다는 걸 알 수 있었다. 그리고 Chang's method는 patient study에서의 AC 값이 phantom study에서의 AC값보다 더 높다는 것을 알 수 있었다. brain SPECT/CT를 시행하는 경우 scatter correction을 같이 시행하고 bone에 의한 감쇠 정보를 반영할 수 있는 AC-CT가 chang's method보다 정확하다 할 수 있겠다. Purpose : The purpose of this study was to compare count between Chang's method and CT-based attenuation correction (AC-CT) among the attenuation correction (AC) methods for non-attenuation correction (AC-non) images of Brain SPECT (Single Photon Emission Computed Tomography). Materials and Methods : We injected $^{99m}Tc$ 37Mbq in a Hoffman 3D phantom filled with distilled water in the phantom study, and injected intravenously $^{99m}Tc$-HMPAO 740Mbq in a normal volunteer in the patient study, and then obtained Brain SPECT images with Symbia T6 of Siemens and conducted quantitative brain analysis. Transverse images to which each method was applied were rebuilt at the same position, and 6 regions of interest (ROI) were drawn on each of Slice No. 10, 20 and 30 and then the counts of AC-non, AC-CT and Chang's method were compared. Results : The mean counts of AC-non, AC-CT and Chang's method were $4606.8{\pm}511.3$, $16794.6{\pm}2429.4$, and $8752.6{\pm}896.5$, respectively, in the phantom study and $5460.8{\pm}519.6$, $15320{\pm}1171.6$ and $12795{\pm}1422.1$, respectively, in the patient study. In the phantom study, the ratio of AC-CT to AC-non was 3.70 and the ratio of Chang's method to AC-non was 1.92, and in the patient study, they were 2.85 and 2.38, respectively. Conclusion : From this study, we found that AC-CT makes higher AC than Chang's method. In addition, when Chang's method was used, AC in the patient study was higher than that in the phantom study. These results need to be considered also in other examinations.

만성 두부외상 환자에서 99mTc - HMPAO Brain SPECT의 임상적 유용성

서정호(Jung Ho Suh),김동익(Dong Ik Kim),정태섭(Tae Sub Chung),이종두(Jong Doo Lee),박창윤(Chang Yoon Park),정진일(Jin Ill Chung),김영수(Young Soo Kim) 대한핵의학회 1992 핵의학 분자영상 Vol.26 No.1

N/A Minima1 deterioration of cerebral perfusion or microanatomical changes were undetectable on conventional Brain CT or MRI. So evaluation of focal functional changes of the brain parenchyme is essential in chronic head injury patients, who did not show focal anatomical changes on these radiological studies. However, the patients who had longstanding neurologic sequelae following head injury, there had been no available imaging modalities for evaluating these patients precisely. Therefore we tried to detect the focal functional changes on the brain parenchyme using Tc-99m-HMPAO Brain SPECT on the patients of chronic head injuries. Twenty three patients who had suffered from headache, memory dysfunction, personality change and insomnia lasting more than six months following head injury were included in our cases, which showed no anatomical abnormalities on Brain CT or MRI. At first they underwent psychological test whether the symptoms were organic or not. Also we were able to evaluate the cerebral perfusion changes with Tc-99m-HMPAO Brain SPECT in 22 patients among the 23, which five patients were focal and 17 patients were nonfocally diffuse perfusion changes. Thus we can predict the perfusion changes such as local vascular deterioration or functional defects using Tc-99m-HMPAO Brain SPECT in the patients who had suffered from post-traumatic sequelae, which changes were undetectable on Brain CT or MRI.

펠던크라이스 기법, 탄성밴드 운동 및 복합운동 적용이 현대무용전공자의 체간근력에 미치는 영향

김채수(Kim Chae-Soo),권혜영(Kwon Hye-Young),이원재(Lee Won-Jae),조창모(Jo Chang-Mo),김진환(Kim Jin-Hwan),주성범(Ju Sung-Bum),이미경(Lee Mi-Kyoung) 한국체육과학회 2011 한국체육과학회지 Vol.20 No.1

This study is carried out to examine the effect of applying Feldenkrais method, elastic band training and combined training on trunk muscle. The subjects of this study were 32 modern dance majors and they were divided into four groups which consists of 8 peoples each, Feldenkrais method group(modern dance + Feldenkrais method), elastic band training group(modern dance + elastic band training), combined training group(modern dance + Feldenkrais method + elastic band training), and control group(modern dance). Measurement variables which are trunk muscle were measured before training, and after 4 and 8 weeks training and the results are as follow: In the left muscle strength change at Centaur 0°, Feldenkrais method group, elastic band training group and combined training group showed significant increase after 8 weeks training compared to before training. In the right muscle strength change, Feldenkrais method group and combined training group had significant increase after 8 weeks training. In the left muscle strength change at Centaur 45°, Feldenkrais method group and combined training group showed significant increase after 8 weeks training compared to before training and after 4 weeks training. Also elastic band training group showed significant increase after 8 weeks training compared to before training. In the right muscle strength change, Feldenkrais method group and elastic band training group significantly increased after 8 weeks training compared to before training. In the left muscle strength change at Centaur 90°, Feldenkrais method group and combined training group showed significant increase after 4 and 8 weeks training compared to before training. In the right muscle strength change, Feldenkrais method group showed significant increase after 4 and 8 weeks training compared to before training, and elastic band training group significantly increased after 8weeks training compared to before training. In the left muscle strength change at Centaur 135°, there was no significant changes. In the right muscle strength change, elastic band training group and combined training group showed significant increase after 8 weeks training compared to before training. In the left muscle strength change at Centaur 180°, combined training group showed significant increase after 4 and 8 weeks training compared to before training. In the right muscle strength change, combined training group showed significant increase after 4 and 8 weeks training compared to before training. From above results, applying 8 weeks regular program of Feldenkrais method, elastic band training and combined training to modern dance majors showed positive changes on improvement of trunk muscle strength and physical strength. Also this study implemented to verify the effects of trunk muscle strength and body balance through supplementary training program, and showed the effects in the training group and control group after 8 weeks trunk muscle strengthening program. Feldenkrais method, elastic band training and combined training are very effective to improve trunk muscle strength of modern dance majors so that continuous implementation and application of these effective training program shall be provided for strengthening trunk muscle.

Effects of aerosol on evaporation, freezing and precipitation in a multiple cloud system

Lee, Seoung Soo,Kim, Byung-Gon,Yum, Seong Soo,Seo, Kyong-Hwan,Jung, Chang-Hoon,Um, Jun Shik,Li, Zhanqing,Hong, JinKyu,Chang, Ki-Ho,Jeong, Jin-Yim Springer-Verlag 2017 Climate dynamics Vol.48 No.3

<P>Aerosol effects on clouds and precipitation account for a large portion of uncertainties in the prediction of the future course of global hydrologic circulations and climate. As a process of a better understanding of interactions between aerosol, clouds and precipitation, simulations are performed for a mixed-phase convective multiple-cloud system over the tropics. Studies on single-cloud systems have shown that aerosol-induced increases in freezing, associated increases in parcel buoyancy and thus the intensity of clouds (or updrafts) are a main mechanism which controls aerosol-cloud-precipitation interactions in convective clouds. However, in the multiple-cloud system that plays much more important roles in global hydrologic circulations and thus climate than single-cloud systems, aerosol effects on condensation play the most important role in aerosol-induced changes in the intensity of clouds and the effects on freezing play a negligible role in those changes. Aerosol-induced enhancement in evaporation intensifies gust fronts and increases the number of subsequently developing clouds, which leads to the substantial increases in condensation and associated intensity of convection. Although aerosol-induced enhancement in freezing takes part in the increases in condensation by inducing stronger convergence around cloud bottom, the increases in condensation are similar to one order of magnitude larger than those in freezing. It is found that while aerosol-induced increases in freezing create intermittent extremely heavy precipitation, aerosol-induced increases in evaporation enhance light and medium precipitation in the multiple-cloud system here. This increase in light and medium precipitation makes it possible that cumulative precipitation increases with increasing aerosol concentration, although the increase is small. It is interesting that the altitude of the maximum of the time- and domain-averaged hydrometeor mass densities is quite robust to increases in aerosol concentration. This is because locations of gust fronts and homogeneous freezing do not vary significantly with changing aerosol concentration and this outweighs aerosol effects on hydrometeor size.</P>

Energy consumptions and associated greenhouse gas emissions in operation phases of urban water reuse systems in Korea

Chang, Jin,Lee, Woojin,Yoon, Sukhwan Elsevier 2017 Journal of Cleaner Production Vol.141 No.-

<P><B>Abstract</B></P> <P>Water reuse systems have been widely implemented across the globe as a solution to water shortage and freshwater contamination. Ongoing controversies regarding supposedly high energy cost and the lack of sufficient data to support benefits of water reuse are delaying further expansion of implementation of water reuse systems in South Korea. In order to clarify the ambiguity regarding the energy demand and provide an unbiased comparison between the water reuse alternatives and the conventional water supply system, energy consumptions and greenhouse gas emissions in operation phases of different water reuse facilities and the conventional water supply system were examined. The average total energy consumption and the greenhouse gas emission of the conventional process were calculated to be 0.511 kWh/m<SUP>3</SUP> and 0.43 kgCO<SUB>2</SUB>e/m<SUP>3</SUP>, respectively. Centralized wastewater reuse systems had prohibitively high energy consumptions (1.224–1.914 kWh/m<SUP>3</SUP>) and greenhouse gas emissions (0.72–0.83 kgCO<SUB>2</SUB>e/m<SUP>3</SUP>). The decentralized wastewater reuse systems, greywater reuse and rainwater harvesting systems, all used for non-potable purposes, had comparable or higher energy demands than the conventional process (0.246–0.970 kWh/m<SUP>3</SUP> after adjustment), although estimated greenhouse gas emissions from these processes were lower than the conventional process (0–0.33 kgCO<SUB>2</SUB>e/m<SUP>3</SUP> after adjustment). Considering the hidden environmental benefit (0.357 kWh/m<SUP>3</SUP>) from reduction of contaminant release, the energy demand of greywater reuse drops far below that of the conventional system, suggesting that decentralized water reuse is the key to an energy-efficient water management with minimal impact on climate change.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Analyses of energy consumptions and GHG emissions from water reuse systems. </LI> <LI> Analyses based on operating data from 8 fully operational reuse systems in Korea. </LI> <LI> Decentralized reuse systems were more energy-efficient than centralized reuse systems. </LI> <LI> Centralized, high purity wastewater reuse systems have very high energy demands. </LI> <LI> Environmental benefits should not be overlooked in assessment of the reuse systems. </LI> </UL> </P>

Structure and Property Modification of Bimodal Molecular Weight Distribution Polyethylene by Electron Beam Irradiation

Lee, Sang-Man,Jeon, Hye-Jin,Choi, Sun-Woong,Song, Hyun-Hoon,Nho, Young-Chang,Cho, Kyu-Cheol The Polymer Society of Korea 2006 Macromolecular Research Vol.14 No.6

Polyethylene of bimodal molecular weight distribution was irradiated with an electron beam. The thermal and mechanical properties were examined by DSC, small and wide angle X-ray scattering and static tensile test according to the crystal morphology of the irradiated samples. The crystal morphology change upon irradiation, as revealed by wide angle X-ray scattering, correlated well with the changes in melting enthalpy, whereas the lamellar thickness and the amorphous gap thickness remained virtually unchanged at irradiation doses up to 500 kGy. Crosslinks in the crystal domains became evident at an energy level of 250 kGy, resulting in reduced crystallinity and crystal size of the (110) and (200) planes. The samples became stiff and brittle with increased irradiation dose, which seem to be more relevant to the amount of cross links than the crystal morphology changes.