• International Journal of Air-Conditioning and Refrigeration
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• 제10권1호
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• pp.50-63
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• 2002

The Karman boundary-layer has been numerically investigated for the disturbance wave number, wave velocity, azimuth angle and radius (Reynolds number, Re). The disturbed flow over rotating disk can lead to transition at a much lower Re than that of the well-known Type I instability. This early transition is due to the excitation of the Type II. Presented are the neutral stability results concerning these instabilities by solving newly formulated stability equations with consideration of whole convective terms. When the present numerical results are compared with the previously known results, the value of critical Re corresponding to Type I is moved from ${Re}_{c.1}$=285.3 to 270.2 and the value corresponding to Type II from ${Re}_{c.2}$=69.4 to 36.9, respectively. Also, the corresponding wave number is moved fro)m $k_1$=0.378 to 0.386 for Type I; from $k_2$=0.279 to 0.385 for Type II. For Type II, the upped limit of wave number and azimuth angle is $k_u$=0.5872, $\varepsilon_u$=$-17.5^{\circ}$, while its lower limit is near $k_u$=0, $\varepsilon_u$=$-28.4^{\circ}$. This implies that the disturbances will be relatively fast amplified at small Re and within narrow bands of wave number compared with the previous results.

• Environmental Analysis Health and Toxicology
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• 제13권3_4호
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• pp.87-94
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• 1998

The use of cisplatin is limited by severe side effects such as renal toxicity. Our platinum-base drug discovery is aimed at developing drugs capable of diminishing toxicity and improving antitumor activity. We synthesized new Pt (II) complex analogue [Pt (cis-DACH)(DPPP)]. 2NO$_3$ (PC) containing cis-1,2-diaminocyclohexane as a carrier ligand and 1,3-bis(diphenylphosphino) propane as a leaving group. Furthermore, nitrate was added to improved the solubility. In this study, its structure was determined and its antitumor activity against SKOV-3 and NIH-OVCAR-3 human ovarian adenocarcinoma, and in vitro cytotoxicity was determined against primary cultured rabbit kidney proximal tubular and renal cortical cells of human kidney using colorimetric MTT assay. PC demonstrated acceptable antitumor activity against SKOV-3 and NIH-OVCAR-3 human ovarian adenocarcinoma and significant activity as compared with that of cisplatin. The toxicity of PC was found quite less than that of cisplatin using MTT and $^3$H-thymidine uptake tests in rabbit proximal tubular cells and human kidney cortical cells. PC was used for human cortical tissue in 7 weeks hitoculture by the glucose-consumption tests. We determined that the new platinum drug has lower nephrotoxicity than cisplatin. Based on these results, this novel platinum (II) complex compound (PC) represent a valuable lead in the development of a new anticancer chemotherapeutic agent capable of improving antitumor activity and low nephrotoxicity.

• 설비공학논문집
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• 제12권8호
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• pp.771-781
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• 2000

The Karman boundary-layer, has been numerically investigated for the disturbance wave number, wave velocity, azimuth angle and radius (Reynolds number, Re). The disturbed flow over rotating disk can lead to transition at a much lower Re than that of the well-known Type 1 mode of instability. This early transition is due to the excitation of the Type II mode. Presented are the neutral stability results concerning these modes by solving new formulated vorticity equations with consideration of whole convective terms. When the present numerical results are compared with the previously known results, the value of critical Re corresponding to Type I is moved from Rec,! =285.3 to 270.2 and the value corresponding to Type II is from $Re_{c,2}$=69.4 to 36.9, respectively. Also, the corresponding wave number is moved from $k_1$ =0.378 to $k_1$ =0.389 for Type I; from $k_2$ =0.279 to $k_2$=0.385 for Type II. For Type II, the upper limit of wave number and azimuth angle is $k_U$=0.5872,$varepsilon_U=-18^{\circ}$ , while its lower limit is$k_L$ =0.05, $varepsilon_L=-27^{\circ}$ This implies that the disturbances will be relatively fast amplified at small Re and within narrow bands of wave number compared with the previous results.

• 한국환경농학회지
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• 제4권1호
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• pp.31-36
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• 1985

현미중(玄米中) 카드뮴, 아연(亞鉛) 및 연(鉛)의 함량추정(含量推定)에 적합(適合)한 토양침출액(土壤浸出液)을 선발(選拔)하여 토양분석치(土壤分析置)를 이용(利用)한 예측모형식(豫測模型式)을 다단계식(多段階式)나으로 분석(分析) 유도(誘導)해 본 결과(結果), 공시(公試)된 침출액(浸出液) 0.1M HCl, 0.1 M $HNO_3$, 0.001M 2Na-EDTA 및 0.1 M $NH_4-oxalate$ 중(中) 현미중(玄米中) 카드뮴과 가장 높은 상관(相關)을 나타낸 침출액(浸出液)은 0.001M 2Na-EDTA였고, 아연(亞鉛)은 0.1N HCl, 연(鉛)은 0.1 M $NH_4-oxalate$였으며 3종김속(種金屬) 모두와 높은 상관정도(相關程度)를 나타낸 침출액(浸出液)은 0.1M $NH_4-oxalate$였다. 또 토양특성(土壤特性)을 이용(利用)한 다중회귀분석결과(多重回歸分析結果) 현미중(玄米中) 카드뮴함양추정(含量推定)에는 pH와 Ca 함양(含量)이 가장 중요(重要)한 변수(變數)로 작용(作用)하였고, 현미중(玄米中) 아은(亞銀)은 CEC 및 Mg 함양(含量)이였으며, 현미중(玄米中) 연함양(鉛含量)은 Na함양(含量)을 제외(除外)한 Ca, CEC, pH, Mg, OM, K등 모든 특성(特性)이 중요(重要)한 변수(變數)였다.

• 한국지반환경공학회 논문집
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• 제15권8호
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• pp.39-44
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• 2014

초임계 조건에서 제조된 망간산화물이 코팅된 활성탄($Mn_3O_4$/AC)에 의한 납 흡착특성을 규명하기 위해 칼럼실험을 통해 파과특성에 미치는 운전변수의 영향에 관해 실험하였다. 활성탄에 망간산화물을 코팅시킴으로써 물질전달대와 평형흡착량은 대략 2.8배 증가하는 것으로 나타났다. 흡착층 높이의 증가는 수용액이 흡착대에 체류하는 시간을 증가시켜 파과시간, 물질전달대와 평형흡착량을 증가시키는 것으로 나타났다. 칼럼으로 공급되는 유량이 증가함에 따라 수용액으로부터 흡착제로 납이 빠르게 전달되어 접촉되므로 파과시간과 물질전달대가 감소하였다. 유량 증가는 흡착대에서 납의 체류시간을 감소시켜 흡착경계면에서의 확산현상을 감소시키므로 평형흡착량을 감소시키는 것으로 나타났다. 칼럼으로 유입되는 납 농도가 증가하면 흡착제로 전달되는 납의 양이 증가하여 물질전달이 빠르게 완료되므로 파과시간과 물질전달대가 감소하는 것으로 나타났다.

• 천문학회지
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• 제28권2호
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• pp.245-253
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• 1995

We have analyzed the time series of Ca II H,K and ${\lambda}8498$ line profiles taken for a sunspot (SPO 5007) with the Echelle spectrograph attached to Vacuum Tower Telescope at Sacramento Peak Solar Observatory. Each set of spectra was taken simultaneously for 20 minutes at a time interval of 30 seconds. A total of 40 photographic films for each line was scanned by a PDS at Korea Astronomy Observatory. The central peak intensity of Ca II H ($I_{max}$), the intensity measured at ${\Delta}{\lambda}=-0.1{\AA}$ from the line center of ${\lambda}8498(I_{{\lambda}8489})$, the radial velocity ($V_r$) and the Doppler width (${\Delta}{\lambda}_D$) estimated from Ca II H have been measured to study the dynamical behaviors of the sunspot chromosphere. Fourier analysis has been carried out for these measured quantities. Our main results are as follows: (1) We have confirmed the 3-minute oscillation being dominant throughout the umbra. The period of oscillations jumps from 180 sec in the umbra to 500 to 1000 sec in the penumbra. (2) The nonlinear character of the umbral oscillation is noted from the observed sawtooth shaped radial velocity fluctuations with amplitudes reaching up to $5{\sim}6\;km/sec$. (3) The spatial distribution of the maximum powers shows that the power of oscillations is stronger in the umbra than in the penumbra. (4) The spatial distributions of the time averaged < $I_{max}$ > and < $V_r$ > across the spot are found to be nearly axially symmetric, implying that the physical quantities derived from the line profiles of Ca II H and ${\lambda}8498$ are inherently associated with the geometry of the magnetic field distribution of the spot. (5) The central peaks of the CaII H emission core lead the upward motions of the umbral atmosphere by $90^{\circ}$, while no phase delay is found in intensities between $I_{max}$ and $I_{{\lambda}8498}$, suggesting that the umbral oscillation is of standing waves.

• 약학회지
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• 제28권4호
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• pp.207-215
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• 1984

Effects of Ssang Wha Tang (SWT), a blended Chinease traditional medicine, on the pharmacokinetics of sulfobromophthalein (BSP) in the rats of hepatic failure induced by carbon tetrachloride were examined. The disposition of plasma BSP in carbon tetrachloride-treated rats (Group I) and in carbon tetrachloride+SWT-treated rats (Group II) followed a three-compartment model, while those in control group followed two-compartment model. GOT, GPT level and some pharmacokinetic paramiters like plasma clearance but except distribution volume (Vdss) recovered in Group II compared to Group I. Therefore, SWT seemed to have an apparent restoring effect of hepatic function damaged by carbon tetrachloride treatment. From the fact that Vdss of BSP in Group II was considered as an one of the probable mechanisms. More intensive increase in BSP-free fraction ($f_p$) in Group II than that in Group I might also explain the increases of BSP clearance and Vdss in Group II compared to Group I. Assuming no changes in hepatic plasma flow(Q) in each group, hepatic intrinsic clearance($CL^h_{int}$) decreased in Group I did not recovered not at all in Group II. Therefore SWT seemed not to have any restoring effect of true hepaticfunction to biotransform and excrete BSP, and the apparent restoring effect of SWT might be due only to the replacement of BSP-plasma protein binding. Whether $f_p$ is actually higer in Group II than in Group I, and Q is constant in each group are being examined in our laboratory. The changes of Q, which might lead to another conculusions, also should be taken into consideration to clarify the apparent hepatorestoring effect of SWT.

• Archives of Pharmacal Research
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• 제27권5호
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• pp.518-523
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• 2004

An allergic reaction ensues after antigen binds to mast cell or basophil high affinity IgE receptor, Fc$\varepsilon$RI, resulting in degranulation of various inflammatory mediators that produce various allergic symptoms. In this study, i) we isolated the active component for the inhibition of mast cell degranulation from the extract of leaves of Castanea crenata and identified it as quercetin; ii) we established the total synthesis procedure of quercetin; iii) using quercetin as positive control, we excavated some lead compounds that possess inhibitory activities for mast cell degranulation by screening the chemical libraries of 1,3-oxazolidine derivatives prepared by solid phase combinatorial chemistry. Some of 1,3-oxazolidine compounds possessing acetyl and 3',4'-dichlorophenyl group displayed strong inhibitory activities on Fc$\varepsilon$RI-mediated mast cell degranulation, suggesting that they can be used as lead compounds for the development of anti-allergic agents.

• Bulletin of the Korean Chemical Society
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• 제26권8호
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• pp.1219-1224
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• 2005

We prepared lead ion-selective PVC membranes that were based on N,N'-bis-thiophene-2-ylmethylene-ethane-1,2-diamine as a membrane carrier. The membrane electrode has a linear dynamic range between 1.0 ${\times}$ $10^{-5}$ and 1.0 ${\times}$ $10^{-1}$ M with a Nernstian slope of 29.79 mV per decade, and its detection limit was 2.04 ${\times}$ $10^{-6}$ M at room temperature. The potentiometric response is independent of the pH of the solution in the pH range of 5-7. The proposed electrode revealed good selectivity and response for $Pb^{2+}$ over a wide variety of other metal ions in pH 5.0 buffer solutions, and there was good reproducibility of the base line on the subsequent measurements. The membrane electrode has a relatively fast response time, satisfactory reproducibility and a relatively long life time.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2005년도 학술발표회 논문집
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• pp.429-436
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• 2005

In this study, we made two types of main control room floor systems (Type I, Type II) and several shaking table tests with and without isolation system were conducted to evaluate floor isolation effectiveness of LRB(Lead Rubber Bearing). Both type showed large difference according to input earthquake signals, but showed little difference according to floor type. It is required to make LRB of which design frequency is below 1Hz when applied to main control room of NPP, but considering much difficulties in making such LRB, it is recommended that consideration should be taken into account when applied to main control room of NPP.