• 한국수자원학회논문집
• /
• 제30권6호
• /
• pp.769-776
• /
• 1997

윤성범과 이기혁(1977)의 수치모형을 이용하여 열발전소의 펌프 비상중단시 냉각수 계통에서 발생하는 서어지거동을 해석하였다. 종래에 무시되었던 기계내부계통으로 부터의 유량, 폐정공기실, 및 공기유출입구, 맨홀, 개수로 및 바다의 영향을 고려하였으며, 이들이 서어지 거동에 미치는 영향을 체계적으로 분석하였다. 특히 공기유출입구의 면적에 따른 서어지 제어효과와 공기실의 공기압 변화를 제시하여 실무에의 적용이 용이하도록 하였다.

• 설비공학논문집
• /
• 제13권3호
• /
• pp.184-193
• /
• 2001

The present study develops programs simulating the internal pressure change of cars due to the change of external pressure when trains run into or passing each other in a tunnel. A new continuous ventilating system control method has been developed in order to alleviate the aural discomfort of passengers riding a high speed train. This method is based on the change of the charged and discharged flow rate by detecting the air pressures generated outside and inside of the train. When the outside and inside pressure are detected, the speed of the charge or exhaust fans and also the valve opening ratios are changed. The elementary performance of the system is checked using dta of the TGV-K high speed train at a speed of 300km/h. Moreover, applicability of the system to the Koran high speed train at a speed of 350 km/h is ascertained by simulation and its effectiveness as a means to alleviate the ear pains is confirmed. This application of the system to the Korean high speed vehicles running in the speed range of 350km/h is considered to have good prospect.

• 한국게임학회 논문지
• /
• 제20권1호
• /
• pp.33-46
• /
• 2020

이 연구는 청소년의 게임 과몰입에 영향을 미치는 요인들이 학교급(초·중·고)에 따라 어떠한 차이가 있는지 살펴보고자 했다. 이를 위해 한국콘텐츠진흥원의 게임이용자패널 데이터를 활용했으며, 내적요인(개인적 특성), 외적요인(환경적 특성), 게임이용 심리변인을 통합적으로 고려했다. 분석결과, 내적요인 중 고독감, 자기통제, 게임이용 심리변인 중 게임리더십, 게임규범성, 게임효능감은 모든 집단에서 공통적으로 게임 과몰입에 영향을 주었으며, 학교급에 따라 게임 과몰입에 영향을 주는 요인들이 차별적인 것으로 확인됐다. 이러한 결과는 청소년의 게임 과몰입에 관한 정책을 수립하거나 프로그램을 개발하는 데 도움을 줄 수 있을 것이다.

• 생물환경조절학회지
• /
• 제1권2호
• /
• pp.175-180
• /
• 1992

수경재배에 적합한 방울토마토 품종선발에 관한 연구결과, 배양액 공급후 시간이 흐를수록 배양액의 pH는 상승했으며 EC는 감소했다. ‘미니캐롤’은 모두 다발화방이었으며, ‘체르시미니’와 ‘뽀뽀’는 single, double, 다발화방이 골고루 나타났다. 각 품종간 생육정도는 별다른 차이를 보이지 않았으나, 수확량에 있어서는 ‘미니캐롤’이 세 품종 중 단연 많았으며, ‘뽀뽀’와 ‘체르시미니’는 별 차이를 보이지 않았다. 당도, 당산비, vitamin C등의 과실의 내적품질은 ‘미니캐롤’에서 좋았다. 관능검사결과 ‘미니캐롤’이 과육의 부드러움, 먹기편한 정도, 껍질의 연도도 등에서 제일 높은 점수를 받아, 세 품종 중 시장성이 가장 좋은 것으로 나타났다.

• 국제초고층학회논문집
• /
• 제2권4호
• /
• pp.293-314
• /
• 2013

Double-Skin Façade (DSF), which is a kind of passive indoor environmental control technique, is effective way to control environmental loads while maintaining the transparency especially in perimeter zone and hence the adoption example of DSF keep increasing recently. The objective of this study was to perform a field survey of air quality environment with natural ventilation through DSF and thermal environment within office building with six stories during a mild climate period in Japan. Moreover, to understand the comprehensive environmental performance of the target building, questionnaire survey was conducted to subjectively evaluate the productivity and satisfaction with the environmental factors in office space. In this field measurement, there was a positive correlation between the DSF internal ventilation flow and the amount of solar radiation on the DSF normal surface; the primary driving force for ventilation in the DSF was considered to be the buoyancy force caused by solar radiation. The results of questionnaire survey with regard to productivity level indicated the need for improvement in the thermal (temperature) and spatial environment (room size and furniture placement).

• 동의생리병리학회지
• /
• 제23권3호
• /
• pp.590-598
• /
• 2009

The purpose of this research is to evaluate the effect of Mahaenggamseok-tang-gagambang (MGTG) on airway hyper- responsiveness (AHR), immune cells, cytokines and lung tissue in OVA-induced asthmatic mice. C578L/6 mice were injected, inhaled and sprayed with OVA for 12 weeks (3times a week) for asthma sensitization and challenge. Two experimental groups were treated with different concentrations of MGTG (400 mg/kg and 200 mg/kg) extract and cyclosporin A (10 mg/kg) for the later 8 weeks. Enhanced pause (Penh) levels were measured by whole body plethysmography. Immune cells were analyzed by flow cytometer in peripheral blood monocyte cell (PBMC) and lung cells. The IL-1b, IL-12, IFN-${\gamma}$, OVA-lgE, IL-4, IL-5, TNF-${\alpha}$ were analyzed by ELISA kit in serum and splenocyte+a-cCDS/a-CD28. Enhanced pause (Penh) levels of the MGTG groups (400 mg/kg and 200 mg/kg) were decreased significantly compared with that of control group. The numbers of MGTG groups (400 mg/kg and 200 mg/kg) on lung total cells were decreased significantly compared with that of control group. The numbers of MGTG groups (400 mg/kg and 200 mg/kg) on $CD3^+/CD69^+$, $B220^+/CD22^+$, $B220^+/CD23^+$, $B220^+/lgE^+$, $CCR3^+$ cells were decreased significantly compared with that of control group. The number of MGTG group (400 mg/kg) on $CD3^+/CD49b^+$ cells was decreased significantly compared with that of control group. The level of MGTG groups (400 mg/kg and 200 mg/kg) on IL-4, IL-5, IL-12, TNF-${\alpha}$, OVA-lgE were decreased significantly compared with that of control group. The level of MGTG group (400 mg/kg) on IL-1b, IL-1S, OVA-lgE were decreased significantly compared with that of control group. These results demonstrate that MGTG could be a desirable alternative therapy for allergic asthma by inhibiting the expression of immune cells, the activation of inflammatory mediator.

• 대한한방내과학회지
• /
• 제21권3호
• /
• pp.467-475
• /
• 2000

The water extracts of Jagamcho-tang has been used for treatment of arrhythmia and palpitation in oriental traditional medicine. Brain is provided with blood flow by heart. Jagamcho-tang has been studied on ischemia and infarction in heart. However, little is known about the mechanism by which the water extracts of Jagamcho-tang rescues brain cells from ischemic damages. To elucidate the protective mechanism on ischemic induced cytotoxicity, the effects of Jagamcho-tang on ischemia induced cytotoxicity and generation of nitric oxide(NO) are investigated in C6 glioma cells. Jagamcho-tang induce NO in a dose dependent manner up to 2.5mg/ml in C6 glioma cells. The pretreatment of Jagamcho-tang protect sodium nitroprusside(SNP) (2mM) induced cytotoxicity. This effect of Jagamcho-tang is mimicked by treatment by pretreatment of SNP($100{\mu}M$), an exogenous NO donor. NG-monomethyl-L-arginine($N^{G}MMA$), a specific inhibitor of nitric oxide synthase (NOS), significantly blocks the protective effects of Jagamcho-tang on cell toxicity by ischemia. In addition, lipopolysaccharide(LPS) and phorhol 12 myristate 13-acetate(PMA) treatment for 72h in C6 glial cells markedly induce NO, but treatment of the cells with the water extracts of Jagamcho-tang decrease nitrite formation in a dose dependent manner. In addition, LPS and PMA treatment for 72h induce severe cell death and LDH release into medium in C6 glial cells. However treatment of the cells with the water extracts of Jagamcho-tang dose not induce significant changes compare to control cells. Furthermore, the protective effects of the water extracts of Jagamcho-tang is mimicked by treatment of $N^{G}MMA$. Taken together, I suggest that the protective effects of the water extracts of Jagamcho-tang against ischemic brain damages may be mediated by regulation of iNOS during ischemic condition.

• Tuberculosis and Respiratory Diseases
• /
• 제75권1호
• /
• pp.9-17
• /
• 2013

Background: In cancer cells, autophagy is generally induced as a pro-survival mechanism in response to treatment-associated genotoxic and metabolic stress. Thus, concurrent autophagy inhibition can be expected to have a synergistic effect with chemotherapy on cancer cell death. Monensin, a polyether antibiotic, is known as an autophagy inhibitor, which interferes with the fusion of autophagosome and lysosome. There have been a few reports of its effect in combination with anticancer drugs. We performed this study to investigate whether erlotinib, an epidermal growth factor receptor inhibitor, or rapamycin, an mammalian target of rapamycin (mTOR) inhibitor, is effective in combination therapy with monensin in non-small cell lung cancer cells. Methods: NCI-H1299 cells were treated with rapamycin or erlotinib, with or without monensin pretreatment, and then subjected to growth inhibition assay, apoptosis analysis by flow cytometry, and cell cycle analysis on the basis of the DNA contents histogram. Finally, a Western blot analysis was done to examine the changes of proteins related to apoptosis and cell cycle control. Results: Monensin synergistically increases growth inhibition and apoptosis induced by rapamycin or erlotinib. The number of cells in the sub-$G_1$ phase increases noticeably after the combination treatment. Increase of proapoptotic proteins, including bax, cleaved caspase 3, and cleaved poly(ADP-ribose) polymerase, and decrease of anti-apoptotic proteins, bcl-2 and bcl-xL, are augmented by the combination treatment with monensin. The promoters of cell cycle progression, notch3 and skp2, decrease and p21, a cyclin-dependent kinase inhibitor, accumulates within the cell during this process. Conclusion: Our findings suggest that concurrent autophagy inhibition could have a role in lung cancer treatment.

• 대한기계학회논문집A
• /
• 제41권11호
• /
• pp.1077-1084
• /
• 2017

기존의 선박용 디젤 엔진에는 항상 일정한 엔진 부하량을 유지하는 캠 구동장치가 적용되고 있었으나, 최근 환경규제로 인하여 엔진 부하량에 따라 실린더 온도를 개별적으로 제어하는 LDCL(Load dependent cylinder liner) JWCS(Jacket water cooling system)가 적용된 전자유압 제어방식이 개발되었다. 이 시스템에서 3-way 밸브는 실린더의 상부와 하부와의 온도 차이를 줄여 저온부식을 방지하는데, 대부분 수입에 의존하고 있으며 토출유량이 낮다. 이에 본 연구에서는 3-way 밸브 내부 형상 관련 설계인자가 성능(토출 유량 및 온도)에 미치는 영향을 파악하여 밸브의 형상 설계를 수행하였으며, 기존 모델과의 성능 비교를 통해 제안된 밸브의 우수성을 검증하였다.

• Tuberculosis and Respiratory Diseases
• /
• 제47권5호
• /
• pp.629-641
• /
• 1999

연구배경: 스테로이드는 천식의 장기적인 치료에 사용하는 약물로 치료효과는 기도에 대한 항염증작용을 통해 이루어지는 것으로 알려져 있다. fluticasone propionate(FP)는 치료효과가 크고 주로 폐에 국소적으로 작용하는 약물로서 beclomethasone dipropionate(BDP)에 비해 2배 정도의 역가를 가지고 있다고 알려져 있다. 이 연구를 통해 FP와 BDP의 치료효과를 비교하고자 하였다. 방 법: 50명의 천식환자를 대상으로 하여 연구를 진행하였다. 환자에게 무작위적으로 FP 혹은 BDP를 4주 동안 투여하였다. 처음 2주간의 Run-in period에는 $\beta_2$-기관지확장제반을 투여하였고 그 후 무작위적으로 FP 또는 BDP를 투여하였다. FP는 diskhaler를 이용하여 하루 2 회 $250{\mu}g$씩 총 $500{\mu}g$을 투여하였고, BDP는 reservoir dry-power device-RPD 를 이용하여 하루 2회 $400{\mu}g$씩 총 $800{\mu}g$을 투여하였다. Run-in period 및 치료 기간 종에 매일 아침과 저녁의 최고호기유량과 주간과 야간의 천식증상점수, 주간과 야간의 응급 & 기관지확장제 사용횟수 등을 측정하였다. $FEV_{1.0}$과 FVC는 치료시작전과 치료 후 2주 간격으로 3 회 측정하였다. 결 과: FP를 투여한 환자 중 3 명과 BDP를 투여한 환자 중 7명이 탈락되어, 총 40명의 천식환자를 대상으로 결과를 분석하였다. FP 및 BDP 투여 후에 아침과 저녁의 최고호기유량이 유의하게 증가하고, 최고호기유량의 일중변이는 유의하게 감소하였다. 폐기능 검사 결과 $FEV_{1.0}$은 FP를 투여한 군에서 증가하고, FVC는 양 군에서 모두 증가하지 않았다. 주간 및 야간의 천식증상 점수가 호전되고, 응급 $\beta_2$-기관지확장제 사용횟수는 유의하게 감소하였다. 그러나 두 군 사이의 치료효과에는 유의한 차이가 없었다. 최고호기유량의 증가, 일중변이의 감소, 증상의 호전 및 응급 $\beta_2$-기관지확장제 사용횟수의 감소는 FP를 투여한 군에서 더 빨리 나타났다. 결 론: 천식환자에게 매일 FP $500{\mu}g$과 BDP $800{\mu}g$을 투여하였을 때, 두 군간의 치료효과는 유사하였다. 효과는 FP를 투여한 군에서 더 빨리 나타났고 부작용으로 치료를 중단한 경우는 없었다.