• 한국건축시공학회지
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• 제18권2호
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• pp.109-115
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• 2018

본 연구에서는 시멘트 생산에 의한 $CO_2$ 배출과 이로 인한 환경 부하를 감소시키기 위해 산업부산물인 고로슬래그 미분말을 활용하여 기존 SCW 공법에 사용되던 시멘트주입재를 친환경 무기결합재로 대체하여 모르타르를 제작하고 친환경 밀크주입재로써 적용이 가능한지를 파악하였다. 본 연구 결과 포틀랜드 시멘트를 사용하지 않은 비소성 시멘트를 이용한 NSB 경화체가 보통 포틀랜드 시멘트 경화체와 비교해 내산성, 내해수성, 압축강도 등이 우수한 것으로 나타나고 있다. 따라서 본 연구를 통해 만들어진 친환경 무기결합재 모르타르는 높은 내구성, 내화학성을 요구하는 SCW 공법과 같은 흙막이벽, 해양하부구조물 등의 지반재료용 결합재에 적용이 가능하다는 것을 알 수 있었다.

• 한국표면공학회지
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• 제38권1호
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• pp.14-20
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• 2005

The control of internal stress is extremely important in electroforming because of the deliberately low adhesion between the electro form and the mandrel. Excessive tensile or compressive stress can cause distortion, separation problem, curling, peeling or separation of electroform prematurely from the mandrel, buckling and blistering. Nickel sulfamate bath has been widely used in electroforming because of its low internal stress and moderate hardness. In this study, real-time stress sensor has been used for stress control in chloride-free nickel sulfamate bath for 400 mm x 300 mm x 500 ㎛ nickel electroform. It was found that compressive stress found at low current density indicated the contamination of electrolyte, which is very useful in procuring buckling and peeling of electroform. No compressive stress is allowed for plate electroform. The real-time stress can also be used for accurate stress control of nickel electroform. The tensile stress was found to be increased slightly with increase in nickel electroform thickness, i.e., from initial 1.47 ksi to 2.02 ksi at 320 ㎛.

• 한국표면공학회지
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• 제38권1호
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• pp.21-27
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• 2005

Tensile properties and hardness of nickel electroform from chloride-free nickel sulfamate electrolyte at 50℃ and PH 4.5 were investigated. Current density varied from 20 to 60 mA/㎠. The deposit thicknesses were 360, 480 and 980 ㎛. It was found in 480 ㎛ thick electroform that highest tensile and yield strengths and hardness of 83.7 ksi, 53.6 ksi and 216 DPH, respectively were obtained at a current density of 40 mA/㎠ and they were slightly decreased at 20 and 60 mA/㎠. However the ductility was lowest of 7.9% at 40 mA/㎠. Such a high strength and low ductility at 40 mA/㎠ seems to be related to the narrower columnar structure than those of other current densities. All the deposits exhibited pronounced necking behavior. Tensile strength, yield strength and ductility increased as the nickel electroform thickens. Initial strong (200) texture developed on stainless steel mandrel decreased and (111) and (220) textures increased as deposit thickness increased, whereas (200) texture was preferred as the current density increased.

• 공업화학
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• 제20권4호
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• pp.386-390
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• 2009

항균효과가 있는 sulfadiazine을 포함하는 아크릴형 단량체를 축합반응으로 합성하였으며, 합성된 아크릴형 단량체와 스티렌 단량체를 함께 라디칼 공중합으로 poly(styrene-co-sulfadiazine)을 합성하였다. 중합체의 중량평균분자량이 27800이었으며, 화학구조와 sulfadiazine과 스티렌 단량체간의 몰비는 핵자기공명분석을 통하여 확인하였다. 이 중합체를 이용하여 15 kV 하에서 전기방사를 수행하여 나노섬유 멤브레인을 제조하였으며, 멤브레인을 구성하고 있는 섬유의 직경은 약 500~800 nm 크기를 가졌다. 제조된 멤브레인의 항균성을 평가하기 위하여 양성균 S. Aureus와 음성균 E. Coli를 사용하였으며, 균주의 colony의 개수 증감으로 항균성을 평가하였다.

• 동의생리병리학회지
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• 제16권2호
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• pp.359-364
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• 2002

The present study examined the effects of water extract of Hwangruynhaedoktang plus Yukmijihwangtang add Chogudeung (HYC) on the blood pressure and renal function in spontaneously hypertensive rats (SHR). The HYC water extract blocked increase of systolic blood pressure (SBP) in SHR. The urinary volume (UV), sodium (UNaV), potassium (UkV), and chloride (UclV) excretions were significantly increased in SHR administered with high dose of water extract of HYC, but urinary osmolality was not changed. The creatinine clearance (Ccr), which is index of glomerular filtration rate (GFR), was increased by administration of HYC, while solute-free water reabsorption (TcH2O) was not changed. Taken together, these results suggest that the depressor effects of HYC, at least in part, caused by diuretic effect due to increase of glomerular filtration rate.

• 동의생리병리학회지
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• 제21권5호
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• pp.1176-1184
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• 2007

Chunmagudeungeumgamibang(CGE) has been used for many years as a therapeutic agent for acute stage of cerebrovascular disease and hypertension in oriental medicine. But the effect of CGE on hypertension and vascular system is not well-known. This study was done to investigate the effects of CGE on hypertension. The results were obtained as follow : CGE showed a safety in cytotoxicity and toxicity of liver. CGE showed scavenging activity on DPPH free radical. CGE showed the inhibitory effect on ROS and ACE. CGE significantly decreased the blood pressure and pulse in DOCA-salt hypertensive rat. CGE significantly decreased the levels of aldosterone in DOCA-salt hypertensive rat. CGE significantly decreased the levels of dopamine, epinephrine in DOCA-salt hypertensive rat. CGE significantly decreased the levels of potassium and chloride in DOCA-salt hypertensive rat. CGE significantly increased the levels of calcium in DOCA-salt hypertensive rat. These results suggest that CGE might be effective in treatment and prevention of hypertension

• 한국식품영양과학회지
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• 제25권4호
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• pp.665-671
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• 1996

토하(Caridina dentiulata dentiulata $D_{E}$ $H_{AAN}$)를 식염 20%로 염장하고 $4\pm1^{\circ}C에서$ 60일 동안 숙성시킨 전남의 전통발효식품인 토하젓의 숙성과정 중 영양성분의 변화를 실험한 결과는 다음과 같다. 토하젓의 유리 아미노산 함량의 변화는 숙성 50일에 최고로 증가하였고 구성 아미노산으로는 glutamic acid가 가장 많았으며 다음으로 leucine, lysine, arginine, glycine 및 alanine의 순이었다. 대부분의 핵산관련물질은hypoxanthine으로 분해되 었으나 ATP와 hnP는 검출되지 않았고 inosine과 IMP는 감소하였다. 숙성과정 중 지방산의 변화로는 포화지방산은 약간 증가 경향을 보였으나 불포화지방산은 점차적으로 감소하였고, 구성 지방산 중에서 palmitic acid가 가장 많았으며 다음으로 palmitoleic acid, linoleic acid, EPA 및 stearic acid의 순이었다. 금속이온의 함량으로는 Na과 Ca이 현저히 많았으며 숙성과정 중의 변화는 거의 없었다. 토하젓의 색도는 숙성이 진행되어감에 따라 명도와 황색도는 증가하였으나 적색도는 큰 변화가 없었다.다.

• 대한한의학방제학회지
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• 제10권1호
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• pp.113-129
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• 2002

The present study designed to investigate whether hwangryunhaedok-tang show an anti-hypertensive effect and elucidate its possible mechanism in spontaneously hypertensive rats. The systolic blood pressures (SBP) were significantly decreased as an oral administration of hwangryunhaedok-tang compared with their control group. The urine volume was significantly increased by administration of hwangryunhaedok-tang but urinary sodium (UNaV), potassium (UKV), chloride excretion (UCIV) were not remarkably affected. The urinary creatinine excretion rate (UcrV) was significantly increased in rats administered with hwangryunhaedok-tang in association with increase of creatinine clearance (Ccr). The urine osmolality (Uosmol) was significantly decreased in SHR administered with hwangryunhaedok-tang without being changed in solute-free water reabsorption ( TcH20). The expressions of Aquaporin 2 (AQP-2). 3 and ${\alpha}\;1$, ${\beta}\;1$ subunits of Na.K-ATPase were determined by Western blot analysis to assess the role of these proteins in association with changes of renal functions in SHR administered with hwangryunhaedok-tang. The expression of AQP-2 and 3 protein was significantly down-regulated in the kidney of SHR administered with hwangryunhaedok-tang compared with those in control rats without being altered expression of ${\alpha}\;1$, ${\beta}\;1$ subunits of Na,K-ATPase. In the in vitro assay, Angiotensin converting enzyme (ACE) was inhibited by hwangryunhaedok-tang in a dose-dependent manner. Berberine and/or palmatine, which are well known as a main components of hwangryunhaedok-tang, also have an ACE inhibitory effects in a dose-dependent manner. Taken together, these results suggest that hwangryunhaedok-tang lowered blood pressure through the increase of diuresis caused by down-regulation of water channels and the inhibition of Angiotensin converting enzyme.

• Environmental Engineering Research
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• 제20권3호
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• pp.246-253
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• 2015

The effects of carbon-to-nitrogen (C/N) ratio in simulated rice straw hydrolysates using glucose and ammonium chloride on polyhydroxyalkanoates (PHA) accumulation by Cupriavidus necator was investigated. In general, PHA accumulation rate was higher under higher degrees of N-deficient conditions (e.g., C/N ratio of 360:1) than lower degrees of N-deficient conditions (e.g., C/N ratio of 3.6:1 and 36:1). Also, the most PHA accumulation was observed during the first 12 h after the PHA accumulation initiation. This study showed that the similar PHA accumulation could be achieved by using different accumulation periods depending on C/N ratios. N source presence was important for new cell production, supported by approximately ten times greater PHA accumulation under the N-deficient condition ($NH_4Cl$ 0.01 g/L) than the N-free (without $NH_4Cl$) condition after 96 h. C/N ratio of the rice straw hydrolysate was approximately 160:1, based on the glucose content, and this accumulated $0.36{\pm}0.0033g/L$ PHA with PHA content of $21{\pm}3.1%$ after 12 h. Since external C or N source addition for C/N ratio adjustment increases production cost, an appropriate accumulation period may be used for PHA accumulation from organic wastes, based on the PHA accumulation patterns observed at various C/N ratios and C and N concentrations.

• KCI Concrete Journal
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• 제14권4호
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• pp.145-150
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• 2002

Reinforced concrete is inherently a durable composite material. When properly designed for the environment to be exposed and carefully constructed, reinforced concrete is capable of giving maintenance-free performance. However, unintentionally using improper materials such as non-washed sea sand having much salt together with poor controlled quality, or the concrete are placed in highly severe environment such as marine atmosphere, the corrosion of reinforcing steel in concrete becomes one of the most significant concerns of concrete. The purpose of this experimental research is to evaluate the performance of corrosion inhibitors for normal strength and high strength concrete, and to propose desirable measures for controlling corrosion of reinforcing steel in concrete. Test specimens in normal strength and high strength concrete were made with and without corrosion inhibitors. The accelerated corrosion test for reinforcing steel in concrete was adopted in accordance with JCI-SC3, which required the periodic 20 cycles for 140 days. One cycle includes 3 days for the wetting condition of $65^{\circ}C$ and $90\%$ RH, and 4 days for the drying condition of $15^{\circ}C\;and\;60\%$ RH. It was observed from the test that corrosion inhibitors in normal strength concrete and high strength concrete showed excellent corrosion resistance for reinforcing steel in concrete, but the silica fume in high strength concrete was found to have a negligible corrosion resistance if not used with corrosion inhibitors, since the chloride corrosion threshold limit in concrete containing silica fume without corrosion inhibitor was found to be considerably smaller than that of the case with corrosion inhibitor.