• 대한한방내과학회지
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• 제38권3호
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• pp.327-335
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• 2017

Objective: The goal of this preclinical study was to compare the dyslipidemic effect of pravastatin with that of herbal medicine in rats. Methods: In total, 40 rats were divided into 4 groups: Normal (10 rats), Control (10 rats), Statin alone (10 rats), and the MO-PM-S group (10 rats), which was given the powder of the cortex of Magnolia officinalis Rehd. et Wils., the root of Polygonum multiflorum Thunb, and pravastatin. The Control group, the Statin alone group, and the MO-PM-S group were all given a high-fat (45%) diet that made them obese. After 2 weeks of drug administration, the dyslipidemic effect of pravastatin was compared with that of herbal medicine in rats by analyzing the lipid profiles, measuring the body weights, and taking biopsies (liver, aorta). Results: The herbal medicine and the statin complex group got a much lower TG level and a slightly higher HDL-cholesterol level than the other groups. However, it got a higher total cholesterol and LDL-cholesterol level than the other groups. In biopsies, 30% of the Statin alone group and 10% of the MO-PM-S group showed mild histopathologic findings in the liver. Conclusion: The cortex of the Magnolia officinalis Rehd. et Wils. and the root of Polygonum multiflorum Thunb have dyslipidemic effects from the perspective of a TG level and HDL-cholesterol. However, the herbal mixture has a raising effect on both the LDL-cholesterol and the total cholesterol levels. Therefore, we cannot conclude that the herbal mixture helps to prevent dyslipidemia. In liver biopsies, the group administered with both the herbal mixture and the statin showed less histopathologic findings than the group administered with statin alone. This means that the herbal mixture helps to prevent fatty degeneration of the liver.

• 한국식품위생안전성학회지
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• 제17권1호
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• pp.8-14
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• 2002

천연식물소재 및 한약재 추출제재인 식물추출 혼합제재가 인체내에서 니코틴 분해능에 미치는 영향을 FRCFR5 세포주, Xenopus oocyte, 임상 실험을 통하여 검토하였다. 본 실험은 체내에 잔존하는 니코틴이 식물추출 홉합 제재에 의해 무독한 대사산물인 코티닌으로 분해량이 증가되고 동시에 NNK, NNN, NNA 등과 같은 폐암 유발물질인 니트로사민 유도체 생성 경로가 억제될 것이라는 가정을 전제로 실험을 수행하였다. 본 실험 결과에서 볼 수 있듯이 식물추출 혼합 제재에는 니코틴에서 코티닌으로 전환시키는 대사 활성물질이 함유되어 있다는 사실을 알 수 있으나, 실제로 어떤 유효성분들이 관여하는지 그리고 정확한 작용 기작을 규명하기 위해서는 더 많은 분석 및 생화학적 연구가 앞으로 수행되어야 할 것이다. 간세포에서 유래된 FRCFR5 세포주 실험 결과, 니코틴과 식물추출 혼합 제재가 첨가된 배지에서 니코틴과 물을 첨가한 배지보다 니코틴에서 코티닌으로 전환능력이 약 2∼3배 높게 나타났으며, 이러한 결과는 Xenopus oocyte에 직접 주사한 경우와 거의 비슷한 양상을 보였다. 임상실험 결과 식물추출 혼합 제재음료를 음용하고 담배를 피운 실험군이 물을 음용하고 담배를 피운 대조군에 비해 약 2배 정도 높은 코티닌 함량을 나타내었다. 이는 실험군의 소변 중에 계속적으로 다량의 코티닌이 배출되는 것을 의미하며, 식물추출 혼합 제재 섭취시 체내에 존재하는 니코틴이 코티닌으로 지속적이면서 효과적으로 전환되는 것을 말한다 이상의 생체 내·외 실험에서 알 수 있듯이 식물추출혼합물은 니코틴에서 코티닌 생성을 약 2배정도 증가 시키는 것을 알 수 있었다.

• 동력기계공학회지
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• 제19권2호
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• pp.64-69
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• 2015

Marine diesel engines with high thermal efficiency and fuel diversity used for propulsive power have been taking charge of important position on marine transport. However, marine environment has recently focused on emissions such as nitrogen oxide and sulfur oxide which is generated from combustion of low grade fuels. EGR(Exhaust gas recirculation) system is one of effective methods to reduce the nitrogen oxide emission from marine diesel engines. In general, it is considered that recirculating gas influences fuel combustion and emissions in diesel engines. However, along with positive effects of EGR, the EGR system using fuels of including high sulfur concentration should be considered about re-combustion and activation of sulfur dioxide in recirculating gas. Therefore, in experimental study, an author investigates effects of sulfur dioxide mixture concentration in intake air on combustion and exhaust emission characteristics in a direct injection diesel engine. In results, change of sulfur dioxide concentrations in intake air had negligible impact on combustion chamber pressure, rate of heat release and emissions compared with effects of oxygen decreasing and carbon dioxide increasing of EGR.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1273-1278
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• 2007

The cement-asphalt mortar is a mixture of cement and asphalt emulsion, and is utilized as a underpouring materials for the railway track which is used to fill under slab panel space so as to provide a stabilized track support and a tool for reduction of noise and vibration. To increase the workability of grouting, this study investigates the effect of temperature on cement-asphalt mortar by analyzing its physical and mechanical properties before/after hardening according to the temperature (10, 15, 20, 25, $30^{\circ}C$). According to the test results, it is found that as for the physical property of fresh cement-asphalt mortar the more mixture temperature become higher or lower, the more fluidity become worse. But by increasing reducing agent amount and its unit quantity, the required fluidity is met. The compressive strength as physical property of hardened cement-asphalt mortar become lower when temperature is lower but taking it by and large the physical properties of cement-asphalt mortar before/after hardening aren't so affected by temperature and well satisfy the requirement. And it has proved that rate of expansion and freezing and thawing resistance aren't affected by temperature.

• 응용통계연구
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• 제22권2호
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• pp.365-373
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• 2009

1990년대에 접어들면서 우리나라는 남아선호사상, 사회경제적 발전, 인구정책 등으로 인해 태아 성감별이나 불법 낙태가 사회적으로 확산되어 출생 성비의 불균형 현상이 초래되었다. 이러한 출생 성비의 불균형 현상을 모니터링 하기 위해서 시계열 분석 또는 지역 차이 분석 등의 많은 연구들이 있었지만 시간과 공판을 동시에 분석에 포함시키지 못했다는 단점이 있다. 본 연구는 시간과 지역성을 동시에 고려하여 출생 성비의 불균형 현상을 분석하였다. 행정구역상으로 구분된 234개의 구, 시, 군 지역에 대하여 2000년과 2001년도의 각 지역별 셋째 자녀 이상의 남녀 출생아 수 자료를 이질적 모집단을 가정하여 이항분포의 혼합모형에 적용시키는 방법을 제안한다. 혼합모형의 위치모수와 가중치, 상관계수 추정은 EM 알고리즘을 통해 수행되었고, ArcView GIS를 이용하여 지역의 이질성을 그림을 통해 표현하였다.

• Journal of Nutrition and Health
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• 제36권5호
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• pp.483-490
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• 2003

Chitosan, hydroxycitrate and L-carnitine have been known to be antiobesity components. The purpose of this study was to evaluate the combined effects of chitosan, hydroxycitrate and L-carnitine mixture as a potential antiobesity supplement in overweight women. Pre-menopausal healthy females who were overweight (percent ideal body weight > 110) were included in this study. Forty-nine subjects randomly received a placebo (n = 25) or antiobesity-supplement (n = 24), which was a mixture of chitosan, hydroxycitrate, and L-carnitine. Before and after the eight-week experimental period, anthropometric parameters, blood components and computerized tomography were measured. At baseline, the two groups were well matched in terms of age, body mass index and lipid profile. After the eight weeks of potential antiobesity supplementation, the subjects' body fat percent had decreased significantly (p < 0.001) by 5.6% (39.1 $\pm$ 1 vs 36.9 $\pm$ 1%) while lean body mass increased (p < 0.01). Vsceral fat area at the L4 vertebra decreased significantly (p < 0.01) by 8.6% in the supplemented group and the total fat area at the L4 vertebra showed a tendency to decrease (p = 0.051) by 2.4%. Also, in the group given the antiobesity-supplement rather than the placebo, the fasting triglyceride level decreased significantly (p < 0.05) by 10.0%. In addition, serum total cholesterol levels in the antiobesity-supplement group showed a tendency to decrease (p=0.159) by 2.7% (194 $\pm$ 6 vs 189 $\pm$ 6 mg/dl). No side effects were found in either group during the intervention. In conclusion, the present study demonstrated that taking a mixture of chitosan, hydroxycitrate, and L-carnitine as a potential antiobesity supplement for eight weeks produced advantageous changes in the weight and visceral fat accumulation of overweight women without any side effects. (Korean J Nutrition 36(5): 483~490, 2003)

• 한국도로학회논문집
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• 제8권1호
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• pp.15-23
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• 2006

현재의 마샬 배합설계는 공극률, VFA. VMA와 함께 가열 아스팔트 혼합물의 현장 공용성과 관련이 적은 안정도와 흐름값을 포함하고 있다. 게다가, 안정도와 흐름값은 거의 대부분 기준값에 만족하며. 최적 아스팔트 함량(OAC)은 공극률, VFA, VMA와 같은 용적특성에 의해 결정되고 있다. 그러므로 많은 연구자들은 현장 공용성과 관계를 가지는 혼합물을 만들기 위하여 안정도와 흐름값을 대신할 수 있는 역학적 특성에 관심을 가지고 있다. 본 연구에서는 마샬 배합설계방법의 안정도와 흐름값을 대신하여 역학적 특성과 관련있는 변형강도$(S_D)$와 파괴에너지(FE)를 도입하는 배합설계를 제안할 것이다. Kim test로부터 소성변형 저항성과 상관성이 높은 변형강도$(S_D)$와, 간접인장시험으로부터 피로균열을 모사하는 파괴에너지 (FE)를 도입하였다. 현재의 배합설계방법과 제안한 배합설계 방법을 비교하기 위하여 4가지 아스팔트 흔합물을 사용하였다. 제안한 배합설계가 현재의 배합설계방법에 비해 OAC결정에 역학적 특성이 반영되는 결과를 볼 수 있었다.

• 한국자동차공학회논문집
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• 제4권2호
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• pp.147-157
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• 1996

Natural gas is gaining more attraction as a future fuel in particular both for environmental protection and energy conservation. In order to bring about more widespread use of gaseous engines, the technology capable of achieving output and efficiency performance equivalent to that of diesel engines needs to be developed. In the present paper, the requirements of the pilot torch from pre-chamber for ensuring ignition and promoting combustion are discussed by means of taking high-speed flame photography and system can run with leaner mixture of various fuels comparing to the electric plug ignition system cause the ignition delay period ignited with the torch and the combustion period are very short in spite of changing A/F of gaseous fuels in the main chamber. However, the suitable piston-cavity design for the use of lower-hydrocarbon fuels such as propane and butane must be discussed increasingly in the mear future.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.41-45
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• 2002

The zone-conditioned CMC equations are derived by taking an unconditional average of the generic conservation equations multiplied by delta and Heaviside functions in terms of mixture fraction and reaction progress variable. The resulting equations are essentially in the same form as the single zone CMC equations except for separate flow fields for burned and unburned gas. The zone-conditioned two-fluid equations are applied to a stagnating turbulent premixed flame brush of Cheng and Shepherd[5l. It is shown that the flame stretch factor is of crucial importance to accurately reproduce the measured mean reaction progress variable and conditional velocities. Further work is in progress for the relationship between surface and volume averages and extension to partially premixed combustion on the basis of a triple flame structure, e. g. in a lifted turbulent diffusion flame.

• 한국자동차공학회논문집
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• 제2권2호
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• pp.103-116
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• 1994

In this study the behavior of engine cooling loss and overall heat transfer coefficient were studied experimentally using naturally aspirated engine and turbo charged engine. Using turbo charging, heat dissipation was increased because of the density of the mixture was increased with increment of inlet air flow rate. Therefore, cooling loss of turbo charged engine is larger than naturally aspirated engine. As taking the measurement of surface temperature of combustion chamber, gas heat transfer coefficient was calculated and found that it has greatly affected to overall heat transfer coefficient. The empirical formula of overall heat transfer coefficient established in order to predict of engine cooling loss and express only as a function of mean piston velocity.