• Title/Summary/Keyword: 유리 전이

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Physical Properties of Flame Retardant Particulate Reinforced Thermoplastic Polymer Composites for Cold-Resistant Cable (내한성 케이블 적용을 위한 난연 입자 강화 열가소성 고분자복합재료의 기계적 특성평가)

  • Lee, Jinwoo;Shim, Seung Bo;Park, Jae Hyung;Lee, Ji Eun
    • Composites Research
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    • v.35 no.5
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    • pp.309-316
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    • 2022
  • The demand for cold-resistant cable material is increasing due to the rapid increase in the development of devices that operate in a low temperature environment. Cold tolerance of a thermoplastic polymer largely depends on the type and content of about 20 or more additives used to make the polymer. The phenomenon of polymer hardening at low temperature can be classified into hardening by simple temperature effect, embrittlement at the glass transition temperature, and hardening by crystallization of polymers that tend to crystallize. In this study, a thermoplastic polymer having a low glass transition temperature, a flame retardant, and an additive were mixed to evaluate the mechanical properties of a thermoplastic polymer composite material for electric wires. It has been confirmed that mechanical properties and processability are determined depending on the additives and compatibilizers added, and this study is considered to be useful as basic data for optimization to meet the performance requirements of wires developed for low-temperature use.

Reconstruction after Wide Excision of Malignant Soft Tissue Tumor in Ankle and Foot (족관절 및 족부에 발생한 연부 조직 악성 종양의 광범위 절제술 후 재건술)

  • Kwon, Young-Ho;Cho, Yool;Kim, Jae-Do;Chung, So-Hak
    • The Journal of the Korean bone and joint tumor society
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    • v.14 no.1
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    • pp.33-43
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    • 2008
  • Purpose: To evaluate the clinical usability of reconstructive methods, and how to select flap after wide excision of malignant soft tissue tumor in ankle and foot. Materials and Methods: The 15 cases shown in the 14 patients (In case of a male patient, reconstruction was performed two times due to local recurrence.) with malignant soft tissue tumor in ankle and foot, who underwent reconstruction after wide excision from March 2000 until March 2007. Oncologic, surgical and functional results were evaluated. Results: The method of reconstruction used were anterolateral thigh perforator flap (5cases), Reversed superficial sural artery flap (4 cases), dorsalis pedis flap (3 cases), local flap (3cases). The defect, mean size was $5.5{\times}5.7\;cm$, was reconstructed with rotation flap or free flap, mean size was $5.9{\times}6.0\;cm$, skin graft for remnant. The mean operation time was 310 minutes (120~540 minutes); it took 256 minutes to reconstruct by rotation flap, and 420 minutes by free flap. As oncologic results, 7 patients were no evidence of disease, 6 patients were alive with disease and 1 patient was expired by pulmonary metastasis at the time of the last follow-up. 4 patients had local recurrence and 4 pateints had distant metastases. As functional results, 14 patients were evaluated with average score of 68.8% using the system of the Musculoskeletal Tumor Society. Conclusion: The dorsalis pedis and reverse superficial sural artery rotation flap which is easy procedure, has less complication and takes short operation time, can be primarily considered to reconstruct a small defect. And the anterolateral thigh perforator flap is suitable for coverage of a large defects after wide excision of malignant soft tissue tumor in ankle and foot.

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Effect of Short Term Treatment with Different Dosage of Inhaled Flucatisone Propionate on Basal Cortisol Concentration (단기간 Fluticasone Propionate 투여 용량에 따른 가저 코르티솔 농도의 변화)

  • Kim, Hyun-Jung;Kim, Hyoung-Sik;Lee, Hong;Moon, Sung-Gi;Lim, Seok-Tae;Park, Ji-Hyun;Lee, Heung-Bum;Lee, Yong-Chul;Rhee, Yang-Keun
    • Tuberculosis and Respiratory Diseases
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    • v.44 no.5
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    • pp.1063-1071
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    • 1997
  • Backgroung : The efficacy of oral corticosteroids in the treatment of chronic asthma is undisputed, but their long-term use is associated with adverse side-effects, including supression of the hypothalamic-pituitary adrenal axis function, osteoporosis, weight gain, hypertension and impaired glucose tolerance. The introduction of inhaled corticosteroids in the early 1970's represented a significant therapeutic advance in the management of asthma, since these compounds combined high topical potency with low systemic activity. Fluticasone propionate is a new topically active synthetic glucocorticosteroid that combinds a high degree of efficacy with negligible systemic bioavailability. This study was perfomed to determine the effect of inhaled fluticasone propionate on the adreocortical supression in patients with bronchial asthma or chronic obstructive pulmonary disease. Method : The adrenocortical function was assessed by measurement of plasma cortisol concentration at 8 o'clock in morning and free cortisol in 24 hour urine collection at interval. Absolutely, no steroid was taken during pretreatment period of 10days. There after each subject inhaled fluticasone aerosol, in daily doses of 500 or 1000micrograms for 12days. The dose was delivered by metered dose inhaler(MDI). Results : The serum cortisol and 24hour urinary free cortisol were not decreased during the treatment period in patients with inhaled fluticasone propionate in daily doses of 500 micrograms. In contrast, serum cortisol was significantly decreased on 9th and 12th day(p less than 0.05). And, 24hour urinary free cortisol was also significantly decreased on 3rd and 12th day of treatement period(p less than 0.05) in patients with inhaled fluticasone in daily doses of 1000 micrograms. Conclusion : These results suggested that endogenous cortisol secretion was not supressed after short-term inhalation of fluticasone in daily dose of 500 micrograms, but in daily dose of 1000 micrograms, the endogenous cortisol secretion was supressed.

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Effects of Zingiber mioga, Zingiber mioga Root and Zingiber officinale on the Lipid Concentration in Hyperlipidemic Rats (양하, 양하근경 및 생강분말이 고지혈증 유발 흰쥐의 지질성분에 미치는 영향)

  • Shin, Jung-Hye;Lee, Soo-Jung;Sung, Nak-Ju
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.31 no.4
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    • pp.679-684
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    • 2002
  • This study was designed to establish the effects of Zingiber mioga, Zingiber mioga root and Zingiber ofiicinale on the lipid concentrations in hyperlipidemic rats. A total of 24 male Sprague-Dawley rats weighing 60$\pm$5g were fed one of four experimental diets for 4 weeks: a control diet (hyperlipidemic diet), diets supplemented with 3% of Z. mioga, 3% Z. mioga roots or 3% Z. officinale. The concentration of total cholesterol in serum was significantly decreased by 31% in Z. mioga group compared to the control group. The HDL-cholesterol concentration was significantly higher in Z. mioga and Z. mioga root supplemented groups than in control group. Triglyceride concentration in serum and liver significantly decreased with 3% Zingiber supplemented groups compared with control group, but had no significant differences among three Zingiber supplemented groups. The contents of total cholesterol triglyceride free cholesterol and cholesteryl ester in liver were remarkably lower in Zingiber supplemented groups than in control group. However, hepatic phospholipid level was not showed significant effect.

Treatment of Early Glassy Cell Carcinoma of Uterine Cervix (초기 자궁경부 유리세포암의 치료)

  • Kim Ok-Bae;Kim Jin-Hee;Choi Tae-Jin
    • Radiation Oncology Journal
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    • v.24 no.2
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    • pp.123-127
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    • 2006
  • Purpose: The purpose of this study was to investigate the clinical findings, treatment, and outcome of patients with glassy cell carcinoma of cervix. Materials and Methods: We reviewed all cases of glassy cell carcinoma of the uterine cervix confirmed and treated at the Dongsan Medical Center, Keimyung University, between January 1993 and December 2005. There were 7 cases with histopathologically confirmed gassy cell carcinoma. A tumor was diagnosed as glassy cell carcinoma if over 50% of the tumor cell type displayed glassy cell features. Six patients with stage IB had radical hysterectomy and bilateral pelvic node dissection, and 2 of them received adjuvant external pelvic irradiation with concurrent chemotherapy. Remaining one patient with stage IIA had curative concurrent chemoradiotherapy with external pelvic irradiation and brachytherapy. Results: There were 7 patients diagnosed as glassy cell carcinoma among the 3,745 (0.2%) patients of carcinoma of uterine cervix. The mean age of 7 patients was 44 years with range of 35 to 53 years of age. The most frequent symptom was vaginal bleeding (86%). By the punch biopsy undertaken before treatment of 7 cases, 2 only cases could diagnose as glassy cell carcinoma of uterine cervix, but remaining of them confirmed by surgical pathological examination. The mean follow up duration was 73 months with range of 13 to 150 months. All 7 patients were alive without disease after treatment. Conclusion: Glassy cell carcinoma of the uterine cervix is a distinct clinicopathologic entity that demonstrates an aggressive biologic behavior. However for early-stage disease, we may have more favorable clinical outcome with radical surgery followed by chemoradiothery.

Continuous Production of Fructooligosaccharides from Sucrose by a Dual Immobilized Enzyme System of Fructosyltransferase and Glucose Isomerase (과당전이효소와 포도당 이성화 효소의 고정화 혼합효소계에 의한 설탕으로부터 프락토올리고당의 연속생산)

  • 윤종원;서근학송승구
    • KSBB Journal
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    • v.10 no.1
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    • pp.9-14
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    • 1995
  • Continuous production of fructooligosaccharides from sucrose by a dual immobilized enzyme system of fructosyltransferase and glucose isomerase was studied in a column reactor. The optimal temperature and pH of the immobilized fructosyltransferase were $65^{\circ}C$ and 5.5, respectively. The activity of glucose isomerase was favorable as temperature and pH were increased within the ranges examined. However, both the immobilized enzymes were thermally unstable over $5^{\circ}C$, suggesting that long-term operation of the dual immobilized enzyme column should be carried out below $50^{\circ}C$. The optimum packing ratio of fructosyltransferase to glucose isomerase was found to be around 5/3. Under the optimized reaction conditions, the dual enzyme column was successfully operated for 40 days without any loss of initial enzyme activities, yielding 66% of fructooligosaccharides. Furthermore, the relative sweetness of fructooligosaccharides produced by a dual emzyme system was enhanced by 6% compared with that of fructosyltransferase alone.

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Effects of impurities on transformation of quartz to cristobalite (Quartz에서 cristobalite로의 전이에 미치는 미량성분의 영향)

  • Jin Kim;Jeong-Hoon
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.4 no.3
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    • pp.315-324
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    • 1994
  • The effects of impurities of the quartz raw materials on the trasformation of quartz to cristobalite were investigated. As the increase of impurities content, the amount of cristobalite crystal increased, whereas the fusion temperature of quartz and the formation temperature of cristobalite decreased. And the courses of the transformation of quartz to cristobalite were examined. The course of quartz $\rightarrow$ transitional noncrystalline phase $\rightarrow$ melt (T) and quartz $\rightarrow$ transitional noncrystalline phase $\rightarrow$ cristobalite $\rightarrow$ melt (C) were always coexisted on the transformation of quartz. In the case of high purity quartz raw material, the T course was predominant, while in low purity quartz raw material, the C course was predominant. And the calculated density of heat treated sand by the quantitative analysis of quartz and cristobalite phase by XRD is well agreed with the measured density by pycnometer. On the melting proces of quartz glass, the volume expansion of sand at a certain temperature can be estimated with the calculated density data.

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Mid-Holocene palaeoenvironmental change at the Yeonsan-dong, Gwangju (홀로신 중기 광주광역시 연산동 일대의 고식생 및 고기후 변화)

  • Park, Jung-Jae;Kim, Min-Koo
    • Journal of the Korean Geographical Society
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    • v.46 no.4
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    • pp.414-425
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    • 2011
  • The aim of this research is to infer paleovegetation and paleoclimate in the Hwajeon archeological site of Gwangju city during mid-Holocene through the analysis of pollen, waterlogged woods, and sediments. Between 8200 ~ 6800 years ago, relatively dry climate resulted in a weakened dominance of oak and high diversity of tree genus. During the Holocene climatic optimum period (6800 ~ 5900 years ago), oak forests expanded while wetland areas diminished as warm/humid climate intensified. Between 5900 ~ 4700 years ago, the entire forest area as well as oak climax forests was reduced due to a relatively cool/dry climate. However at the end of this period, oak forests expanded since a favorable climate condition temporarily resumed. Lastly, between 4700 ~ 3300 years ago, oaks dominated but alders were weakened. The density of forest was low because of a relatively dry climate in this period.

Chemical Components of Chestnut Flower(Castanea crenata) (밤꽃의 화학성분)

  • 이용수;서권일;심기환
    • Journal of the East Asian Society of Dietary Life
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    • v.7 no.3
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    • pp.309-314
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    • 1997
  • To obtain fundamental data from chestnut flower, chemical properties were investigated. The results are as follows. The contents of total sugar, reducing sugar, crude protein, crude fat and ash in prebloomed chestnut flower were 10.44, 4.91, 8.80, 1.42 and 0.87%, in the postbloomed were 11, 75, 7.04, 7.71, 2.26 and 0.66%, respectively. The browning degree of the extracts from the prebloomed sample was higher than that of the postbloomed. The contents of flavonoids and nonflavonoids in the prebloomed sample were 7.05 and 0.52%, in the postbloomed were 2.08% and 0.22%, respectively. The contents of free sugars such as sucrose, fructose and glucose in the prebloomed sample were 2.90, 0.72 and 0.71%, in the postbloomed were 2.65, 2.10 and 2.20%, respectively. The major amino acids in the prebloomed sample were threonine, proline and cystine and its contents were 28.96, 12.49 and 11.43%. But aspartic are glutamic acid were major amino acids in the postbloomed and its contents were 16.19 and 11.90%, respectively.

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Analysis of Temperature and Total Heat of Heated Glass through Experimental Measurement and Three-Dimensional Steady-State Heat Transfer Analysis (실측실험과 3차원 정상상태 열전달 해석을 통한 발열유리의 온도 및 전열량 분석)

  • Lee, Do-Hyung;Yoon, Jong-Ho;Oh, Myeong-Hwan
    • KIEAE Journal
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    • v.15 no.1
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    • pp.111-116
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    • 2015
  • Heat loss from windows and condensation occuring on its surface due to its lower insulation value causes much discomfort to occupants. In this study, Heated glass was used to make a basic study on prevention of condensation on glass surface for its heating functionality through experimental measurement and simulation analysis of total heat flux on the interior and exterior surface of glass. Error between experimental results and three dimensional steady-state heat transfer analysis were caused firstly, beacuse in the experimental chambers, cold chamber and steady temperature and humidity chamber, air temperature setting was not constant but rather ON/OFF control, and secondly, due to error rate in heat flux meter due to heat flux direction even in stable conditions.