• 한국의학물리학회:학술대회논문집
• /
• 한국의학물리학회 2004년도 제29회 추계학술대회 발표논문집
• /
• pp.39-42
• /
• 2004

빔선질보정인수(kQ)의 인자 중에서 이온함 중심전극 물질의 공기 비등가성에 대한 보정인수 Pcel 값은 TG-51이 기준 깊이로 정한 물 깊이 10cm에 기반하지 않고 5cm에 기반한 데이터를 사용하고 있다. 본 연구의 목적은 선량계의 깊이가 5cm 에서 10cm로 변화함에 따라 광자의 에너지스펙트럼의 변화가 예상되며 이로 인한 Pcel 값 (그리고 이에 따른 Pcel 결정식)의 변화 정도를 몬테칼로 전산모사 방법을 통하여 확인하는데 있다. 확인 결과, 선량계의 깊이가 5cm에서 10cm로 변화하더라도 Pcel 값은 0.2% 통계오차 범위 내에서 차이가 없음을 알 수 있었다.

• 한국의학물리학회지:의학물리
• /
• 제29권1호
• /
• pp.16-22
• /
• 2018

Current dosimetry protocols recommend the use of parallel-plate chambers in electron dosimetry because the electron fluence perturbation can be effectively minimized. However, substitutable methods to calibrate and measure the electron output and energy with the widely used cylindrical chamber should be developed in case a parallel-plate chamber is unavailable. In this study, we measured the correction factors and absolute dose-to-water of electrons with energies of 4, 6, 9, 12, 16, and 20 MeV using Farmer-type and Roos chambers by varying the dose rates according to the AAPM TG-51 protocol. The ion recombination factor and absolute dose were found to be varied across the chamber types, energy, and dose rate, and these phenomena were remarkable at a low energy (4 MeV), which was in good agreement with literature. While the ion recombination factor showed a difference across chamber types of less than 0.4%, the absolute dose differences between them were largest at 4 MeV at approximately 1.5%. We therefore found that the absolute dose with respect to the dose rate was strongly influenced by ion-collection efficiency. Although more rigorous validation with other types of chambers and protocols should be performed, the outcome of the study shows the feasibility of replacing the parallel-plate chamber with the cylindrical chamber in electron dosimetry.

• 한국결정성장학회지
• /
• 제24권6호
• /
• pp.256-260
• /
• 2014

본 연구는 코발트 코팅 두께에 따른 점토 표면과의 반응성을 연구하였다. 시편에서 표면으로 부터 일정한 두께로 코발트가 확산된 것을 볼 수가 있으며, 황화코발트의 도포양과 함께 청자토보다 백자토에서 확산층의 두께가 증가하였다. 백자토에 코팅된 시편은 grayish blue가 blue 색으로 변화되는 것을 알 수 있으며 $L^*$값이 51.78에서 37.61로 감소하고, 청자토에 코팅된 시편인 경우 dark olive gray에서 dark gray색으로 $L^*$값이 53.91에서 38.93로 적어지는 것을 알 수가 있다. 시편의 물성 평가는 XRD, SEM, 열팽창기, TG-DTA, UV-vis spectrophotometer와 HRDPM을 이용하였다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
• /
• pp.311-311
• /
• 2016

최근 고성능 디스플레이 개발이 요구되면서 기존 비정질 실리콘(a-Si)을 대체할 산화물 반도체에 대한 연구 관심이 급증하고 있다. 여러 종류의 산화물 반도체 중 a-IGZO (amorphous indium-gallium-zinc oxide)가 높은 전계효과 이동도, 저온 공정, 넓은 밴드갭으로 인한 투명성 등의 장점을 가지며 가장 연구가 활발하게 보고되고 있다. 기존에는 SG(단일 게이트) TFT가 주로 제작 되었지만 본 연구에서는 DG(이중 게이트) 구조를 적용하여 고성능의 a-IGZO 기반 박막 트랜지스터(TFT)를 구현하였다. SG mode에서는 하나의 게이트가 채널 전체 영역을 제어하지만, double gate mode에서는 상, 하부 두 개의 게이트가 동시에 채널 영역을 제어하기 때문에 채널층의 형성이 빠르게 이루어지고, 이는 TFT 스위칭 속도를 향상시킨다. 또한, 상호 모듈레이션 효과로 인해 S.S(subthreshold swing)값이 낮아질 뿐만 아니라, 상(TG), 하부 게이트(BG) 절연막의 계면 산란 현상이 줄어들기 때문에 이동도가 향상되고 누설전류 감소 및 안정성이 향상되는 효과를 얻을 수 있다. Dual gate mode로 동작을 시키면, TG(BG)에는 일정한 positive(or negative)전압을 인가하면서 BG(TG)에 전압을 가해주게 된다. 이 때, 소자의 채널층은 depletion(or enhancement) mode로 동작하여 다른 전기적인 특성에는 영향을 미치지 않으면서 문턱 전압을 쉽게 조절 할 수 있는 장점도 있다. 제작된 소자는 p-type bulk silicon 위에 thermal SiO2 산화막이 100 nm 형성된 기판을 사용하였다. 표준 RCA 클리닝을 진행한 후 BG 형성을 위해 150 nm 두께의 ITO를 증착하고, BG 절연막으로 두께의 SiO2를 300 nm 증착하였다. 이 후, 채널층 형성을 위하여 50 nm 두께의 a-IGZO를 증착하였고, 소스/드레인(S/D) 전극은 BG와 동일한 조건으로 ITO 100 nm를 증착하였다. TG 절연막은 BG 절연막과 동일한 조건에서 SiO2를 50 nm 증착하였다. TG는 S/D 증착 조건과 동일한 조건에서, 150 nm 두께로 증착 하였다. 전극 물질과, 절연막 물질은 모두 RF magnetron sputter를 이용하여 증착되었고, 또한 모든 patterning 과정은 표준 photolithography, wet etching, lift-off 공정을 통하여 이루어졌다. 후속 열처리 공정으로 퍼니스에서 질소 가스 분위기, $300^{\circ}C$ 온도에서 30 분 동안 진행하였다. 결과적으로 $9.06cm2/V{\cdot}s$, 255.7 mV/dec, $1.8{\times}106$의 전계효과 이동도, S.S, on-off ratio값을 갖는 SG와 비교하여 double gate mode에서는 $51.3cm2/V{\cdot}s$, 110.7 mV/dec, $3.2{\times}108$의 값을 나타내며 훌륭한 전기적 특성을 보였고, dual gate mode에서는 약 5.22의 coupling ratio를 나타내었다. 따라서 산화물 반도체 a-IGZO TFT의 이중게이트 구조는 우수한 전기적 특성을 나타내며 차세대 디스플레이 시장에서 훌륭한 역할을 할 것으로 기대된다.

• Journal of Nutrition and Health
• /
• 제38권3호
• /
• pp.197-202
• /
• 2005

Resistin, adiponectin, and leptin are hormones secreted by adipose tissue and are known to play an important role in adipose tissue metabolism. The purpose of this study was to evaluate the levels of adipocyte-derived hormones (resistin, adiponectin, leptin) in obese children aged 10-12 years. The subjects were 102 obese children with obesity index (OI) over $120\%$ and 51 control children with obesity index less than $120\%$ were included for comparison. Anthropometric variables and serological parameters were assessed. Height, weight, OI, body mass index (BMI) were significantly higher in obese group than in control. Obese children showed significantly higher serum concentrations of triglyceride (TG), total cholesterol (TC), and LDL-cho1esterol and significantly lower HDL-cholesterol compared with control children, even though the values were within normal ranges for both groups. Concentrations of resistin and leptin were significantly higher in obese group than in control. Adiponectin and insulin levels were tended to lower in obese group even though the differences were not statistically significant. Resistin had significant positive correlation with OI and TG, and 1eptin with weight, OI, BMI, TG and TC. On the other hand, adiponectin showed significant negative correlations with height, OI and BMI. These finding showed that obese children had higher serum levels of resistin and leptin and lower adiponectin, and also these hormones had correlations with related factors of obesity, suggesting adipocyte-derived hormones has a role in child obesity.

• 대한지역사회영양학회지
• /
• 제2권1호
• /
• pp.44-51
• /
• 1997

Secrum lipid and vitamin E levels were determined and smoking, alcohol drinking and exercise habits were asked in 357 healthy male subjects aged 49.4$\pm$6.7 years in Taegu. Average serum levels of total cholesterol, HDL-cholesterol and triglyceride(TG) were 189$\pm$43mg/이, 42$\pm$13mg/dl and 136$\pm$73mg/이, respectively. Serum level of lipid peroxide measured as thiobarbituric acid reactive substances(TBARS) of the subjects was 2.01$\pm$0.73MDA nmoles/ml and that of $\alpha$-tocopherol was 9.53$\pm$3.14ug/ml. The correlation coefficients between $\alpha$-tocopherol and serum lipids were 0.3631 for triglyceride, 0.2993 for cholesterol, and 0.3025 for total lipid. Heavy smokers who smoked more than 20 cigarettes a day had higher levels of TG and TBARS than those who smoke less. Alcohol drinkers had higher levels of TG and TBARS than nondrinkers. Vitamin E level(per ml serum)was significantly higher in the heavy smokers and drinkers, which was reflected by the higher level of serum lipid. When the level of $\alpha$-tocopherol was expressed as $\alpha$-tocopherol/triglyceride, it was negatively correlated with serum TBARS level and was lower in the heavy smokers than in the moderate smokers. It is concluded that vitamin E level as $\alpha$-tocopherol/triglyceride would be better compared to $\alpha$-tocopherol/total cholesterol or $\alpha$-tocopherol/total lipid for the evaluation of vitamin E status in Korean men.

• 한국임상약학회지
• /
• 제16권1호
• /
• pp.46-51
• /
• 2006

Dyslipidemia is an important CHD risk factor in diabetic patients. We conducted this study to assess the pattern of dyslipidemia in type 2 diabetes patients, to examine the demographic and clinical factors associated with dyslipidemia and to evaluate attaining within the lipid target goals and treatment strategies. A retrospective analysis was conducted among patents diagnosed type 2 diabetes at outpatient clinic in endocrinology between January 2003 and December 2004. Clinical history and physical examination were reviewed and laboratory data including blood glucose, HbAlc, lipid levels were recorded sequentially at least 1 year. In 882 patients with type 2 diabetes, 437 patients (49.6%) have dyslipidemia and 73% of them (319 patients) received lipid-lowering agents. 244 patients (94 males, 150 females, mean age 60 years old) were susceptible to analyses. The most frequent pattern of dyslipidemia is high LDL level and high TG levels (28%). Metabolic syndrome and macrovascular complication were significant negative independent association with lipid levels within the target goals (p<0.05). Only 15.2% (19 males, 18 females) attained within the lipid tar- get goals. Patients with diabetic dyslipidemia need maximization of lipid-lowering agents, increasing the fibric acid derivatives prescription and the effort to correction of low HDL and/or high TG.

• Nuclear Engineering and Technology
• /
• 제51권3호
• /
• pp.746-754
• /
• 2019

Vitrification of radioactive liquid waste (RLW) provides a feasible solution for isolating radionuclides from the biosphere for an extended period. In vitrification, base glass and radioactive waste are added simultaneously into the melter. Determination of heat and mass transfer rates is necessary for rational design and sizing of melter. For obtaining an assured product quality, knowledge of reaction kinetics associated with the thermal decomposition of waste constituents is essential. In this study Thermogravimetry (TG) - Differential Thermogravimetry (DTG) of eight kinds of nitrates and two oxides, which are major components of RLW, is investigated in the temperature range of 298-1273 K in the presence of base glasses of five component (5C) and seven component (7C). Studies on thermal behavior of constituents in RLW were carried out at heating rates ranging from 10 to $40\;K\;min^{-1}$ using TG - DTG. Thermal behavior and related kinetic parameters of waste constituents, in the presence of 5C and 7C base glass compositions were also investigated. The activation energy, pre-exponential factor and order of the reaction for the thermal decomposition of 24% waste oxide loaded glasses were estimated using Kissinger method.

• 한국수산과학회지
• /
• 제17권6호
• /
• pp.477-484
• /
• 1984

전보에 이어 뱀장어의 지질을 부위별로 유리 및 결합지질로 추출하여 중성, 당 및 인지질로 분획한 다음, 그 구성지질 및 지방산조성을 분석, 비교한 결과를 요약한다. 1. 조지질함량은 육질부가 24.94로 가장 많고 피부(20.00), 내장부(14.96)의 순으로 감소하였으며, 다른 어류에 비해 지질 함량이 월등히 많았다. 부위별로 유리 및 결합지질의 함량을 비교해 보면 유리지질은 육질부(57.57)와 피부(45.29)에 많은 반면 결합지질은 내장부(19.41)에 많았다. 2. 유리지질은 중성지질이 86.71~94.94로 가장 많고 인지질(4.13~12.74), 당지질(0.63~1.22)의 순이었고 결합지질은 유리지질과는 반대로 인지질이 51.74~75.21로 가장 많은 반면 중성지질이 14.41~36.82로 적었다. 3. 중성지질 중의 구성지질함량을 보면 유리지질은 TG가 68.51~95.22로 대부분을 차지하고 있는 반면 결합지질은 TG (36.54~39.94), ES & HC(17.20~18.01), MG(15.81~18.11) 등으로 고루 분포되어 있었다. 또 인지질 중의 구성지질 함양은 유리지질은 PC (32.40~56.08), PE (18.71~31.09), PS(8.63~15.54), FA(1.96~7.05)의 순으로 결합지질은 PC(42.51~67.90), PS(23.37~34.49), PE(7.41~10.00), FA(1.12~3.09)의 순으로 감소하고 있었다. 4. 극성지질의 중요 구성지방산을 유리 및 결합지질로 비교하여 보면 $C_{16:0}$(16.58,14.10), $C_{18:0}$(12.44, 7.36), $C_{18:1}$(16.01, 15.78), $C_{20:4}$(10.01, 6.11) $C_{20:5}$(4.20, 8.67) $C_{22:6}$(10.26, 18.32)인 반면 비극성지질의 경우는 $C_{16:0}$(22.31, 18.61), $C_{18:0}$(4.36, 5.69), $C_{18:1}$(36.30, 27.20) $C_{20:5}$(2.88, 2.38) $C_{22:5}$(6.38, 5.11) $C_{22:6}$(1.20, 5.11)였다. 5. 총필수지방산 함량(TEFA)을 보면 극성지질이 17.33~22.88로서 비극성지질(5.21~11.54) 보다 2.0~3.0배 정도 높았으며, 또 결합지질(11.54~22.88)이 유리지질(5.21~17.33) 보다 1.5~2.0배 정도 높았다. 또 w3-고도불포화지방산(w3-HUFA)은 극성지질이 18.63~42.85로서 비극성지질(11.48~14.42) 보다 높았으며 결합지질(13.35~42.85)이 유리지질(11.48~18.63) 보다 높았다. 부위별로는 육질부(17.24~26.26)가 피부(15.56~16.36)나 내장부(8.82~16.99) 보다 높음을 알 수 있었다.

• 대한지역사회영양학회지
• /
• 제6권1호
• /
• pp.51-68
• /
• 2001

This investigation studied the relationship between Body Mass Index(BMI) and dietary intake, levels of serum lipid, lipoprotein(a) and plasminogen activator inhibitor-1(PAI-1) of 28.449 Korean adults(16.937 men, 11.542 women) from 1995 to 1999. The dietary assessment was conducted using 24-hour dietary records and food frequency questionnaires. During this five year study, the BMI normal-weight group, as a percentage of the annual test population, decreased from 68.0% to 60.2%, while the BMI overweight and obese groups collectively increased from 25.0% to 29.7%. The levels of serum total cholesterol (TC), LDL-cholesterol(LDL-C), Triacylglycerol(TG) and PAI-1 increased as the values of BMI increased, while the levels of HDL-cholesterol(HDL-C) and lipoprotein(a)(men only) appeared to decrease as values of BMI increased. The levels of daily energy intake also increased as values of BMI increased in both men and women. The obese group had significantly higher levels of carbohydrate, protein, fat(men only), and cholesterol intake than those of the normal-weight, underweight, and overweight groups. In men, BMI positively correlated with the levels of macronutrients and cholesterol intake(p＜0.001), % energy of protein, fat, and alcohol intake(p＜0.001), and the levels of serum TC, LDL-C, TG and PAI-1(p＜0.001), while BMI negatively correlated with % energy of carbohydrate intake, and the levels of Lp(a) and HDL-C(p＜0.001). In women, BMI negatively correlated with level of cholesterol(p＜0.01), fat(p＜0.001), alcohol intake(p＜0.05),% energy of fat (p＜0.001), % energy of alcohol intake and level of and HDL-C(p＜0.001). Subjects who had serum TC, LDL-C, HDL-C, and TG levels greater than the standard reference values(TC＞240mg/㎗, LDL-C＞130mg/㎗, HDL-C＞35, TG＞200mg/㎗) exhibited a higher intake of the three macronutrients, iron, calcium, meat, milk and fatty foods than those subjects who had serum lipid concentrations less-than-or-equal-to the standard reference values. Overall, there was positive correlation between the high risk factors of vascular disease variables, dietary intake, and BMI. Prevalence of hypertension and high blood sugar were increased as BMI increased, but the prevalence of hypertension is decreased as the year goes by. These findings showed that dietary intake, level of serum lipids and other vascular disease risk factors increased as BIM increased. Therefore, middle or upper class Korean adults who have high BMI should improve their eating habits. This involve reducing alcohol, animal fat, high carbohydrate foods, and overall food intake, and balancing intake in order to lower vascular disease risk factors, including obesity.