• 한국재료학회지
• /
• 제8권5호
• /
• pp.408-412
• /
• 1998

Bi$_{2}$(Te$_{1-x}$Se$_{ x}$)$_{3}$(0.05$\leq$x$\leq$0.25)합금분말을 기계적 합금화 공정으로 제조하여 가압소결 후, $Bi_{2}$Se$_{3}$함량에 따른 열전특성의 변화거동을 분석하였다. 기계적 합금화로 제조한 $ Bi_{2}$(Te$_{1-x}$ $Se_{x}$$_{3}$ 가압소결체는 단결정과는 달리 donor dopant의 첨가없이도 n형 전도를 나타내었다. $Bi_2(Te_{0.85}Se_{0.15})_3$ 합금분말을 (50%H$_{2}$+50% Ar)분위기 중에서 환원처리하여 가압소결시, 분말 효면의 산화층 제거와 과잉 Te 공격자의 소멸에 기인한 전자 농도의 감소로 p형으로 천이되었다. 기계적 합금화로 제조한 $ Bi_{2}$($Te_{1-x}$ $Se_{x}$$_{3}$가압소결체는 x=0.15조성에서 $1.92{\times}10^{-3}$ K의 최대 성능지수를 나타내었다.

• 분석과학
• /
• 제35권5호
• /
• pp.205-211
• /
• 2022

Deuterium (D) is an isotope with one more neutron number than hydrogen (H). Heavy elements rarely change their chemical properties with little effect even if the number of neutrons increases, but low-mass elements change their vibration energy, diffusion rate, and reaction rate because the effect cannot be ignored, which is called an isotope effect. Recently, in the semiconductor and display industries, there is a trend to replace hydrogen gas (H₂) with deuterium gas (D₂) in order to improve process stability and product quality by using the isotope effect. In addition, as the demand for D₂ in industries increases, domestic gas producers are making efforts to produce and supply D₂ on their own. In the case of high purity D₂, most of them are produced by electrolysis of heavy water (D₂O), and among D₂, hydrogen deuteride (HD) molecules are present as isotope impurities. Therefore, in order to maximize the isotope effect of hydrogen in the electronic industry, HD, which is an isotope impurity of D₂ used in the process, should be small amount. To this end, purity analysis of D₂ for industrial processing is essential. In this study, HD quantitative analysis of D₂ for high purity D₂ purity analysis was established and hydrogen isotope RM (Reference material) was developed. Since hydrogen isotopes are difficult to analyze with general gas analysis instrument, they were analyzed using a high-precision mass spectrometer (Gas/MS, Finnigan MAT271). High purity HD gas was injected into Gas/MS, sensitivity was determined by a signal according to pressure, and HD concentrations in two bottles of D₂ were quantified using the corresponding sensitivity. The amount fraction of HD in each D₂ was (4518 ± 275) μmol/mol, (2282 ± 144) μmol/mol. D₂, which quantifies HD amount using the developed quantitative analysis method, will be manufactured with hydrogen isotope RM and distributed for quality management and maintenance of electronic industries and gas producers in the future.

• 대한환경공학회지
• /
• 제34권7호
• /
• pp.445-453
• /
• 2012

본 연구에서는 PAHs 오염토양의 자연 풍화 및 화학적 생물학적 처리과정에서 반응부산물로 흔히 발견되는 PAH-케톤화합물인 1-indanon (1-ID)을 대상으로 페놀계 반응매개체 존재 하에서의 망간산화물에 의한 산화 변환 제거특성 및 용존 자연유기물인 휴믹산(HA)의 존재에 따른 영향을 조사하였다. 반응성 평가 실험은 수용액 상에서 회분식(10 mg/L 1-ID, 0.3 mM phenolic mediators, $1.0g/L\;{\delta}-MnO_2$, at pH 5)으로 수행 하였으며, 페놀계의 반응매개체(phenolic mediator)는 자연산 페놀화합물로서 휴믹물질의 모델 화합물로서도 널리 사용되고 있는 11종을 사용하였다. 실험결과 1-ID은 망간산화물 자체에 대하여는 비반응성을 띠었으나 페놀계 반응매개체 존재 하에서 교차-결합(cross-coupling)반응을 통해 제거됨을 HPLC 분석을 통해 확인하였으며, 1-ID의 제거율은 반응 2일 경과 후 9.2~71.2%범위에서 페놀계 반응매개체의 구조적 특성에 따라 다르게 나타났다. 각 반응매개체 존재 하에서의 1-ID의 교차결합 반응은 유사1차 반응 속도식을 따랐으며, 초기 반응속도 상수 값($K_{int}$, $hr^{-1}$)은 0.48~15.0의 넓은 범위에서 나타났다. 1-ID의 제거효율(제거율, 속도상수)은 -OH, $-OCH_3$ 등 전자주게(electron donating) 작용기를 포함하는 반응매개체에서 높았으며, -COOH, -CHO 등 전자받게(electron withdrowing) 작용기를 포함하는 반응매개체일수록 낮았다. 또한 동일 반응 조건에서 HA 존재에 따른 영향을 검토한 결과 낮은 HA 농도(< 2 mg/L) 조건에서는 1-ID 제거효율의 상승효과를 보였으나 전체적으로는 HA 주입 농도가 증가할수록 교차 결합 반응효율이 저하됨을 확인하였다.

• 한국산학기술학회논문지
• /
• 제18권9호
• /
• pp.436-443
• /
• 2017

최근, 지구온난화 등의 문제로 인해 새로운 에너지 기술의 개발이 화제가 되고 있다. 중규모 이상의 출력을 얻도록 최적화된 태양광 및 태양열, 풍력 발전과 같은 신재생에너지 기술과 다르게 에너지 하베스팅기술은 출력전력이 매우 작아 크게 주목받지 못하고 있다. 하지만 최근 모바일 산업이 활성화 되면서 에너지 하베스팅기술의 활용가치가 재평가 받고 있다. 또한, 최대전력점 추적방식기술 역시 활발히 연구가 이루어지고 있다. 본 논문에서는 일정한 저항부하를 위한 열전모듈의 새로운 최대전력점추적 제어방식을 제안한다. 열전 모듈(이하 TEM: Thermoelectric Module)의 V-I곡선특성과 내부저항을 분석하고. 기존의 MPPT제어방식을 비교하였다. P&O(Perturbation and Observation)제어방식은 전압, 전류를 측정하기위한 센서 2개를 사용해야하기 때문에 CV제어방식보다 경제성이 떨어지지만 보다 정확히 MPP를 찾는다는 장점을 가진다. CV(Constant Voltage)제어방식은 전압센서 1개만 사용하기 때문에 경제적인 측면에서는 P&O제어방식보다 뛰어나지만, MPP가 정확히 못하다는 단점을 가지고 있다. 본 논문에서는 두 제어방식의 장점만을 가지고 TEM의 최대전력점(MPP)을 추적하도록 설계하였다. 제안된 MPPT 제어 방식은 PSIM 프로그램을 이용한 모의실험으로 확인하였으며, 하드웨어제작을 통해 제안된 MPPT제어 방식을 검증하였다.

• Journal of Acupuncture Research
• /
• 제33권2호
• /
• pp.35-49
• /
• 2016

Objectives : This study was designed to investigate the anti-osteoarthritic effects of clematidis radix pharmacopuncture on the MIA-induced osteoarthritis rats. Methods : The subjects were divided into 4 groups ; Normal rat group(N, n=5), MIA-induced osteoarthritis control rat group(C, n=5), MIA-induced osteoarthritis rat group injected with normal saline at ST36(NS, n=5), and MIA-induced osteoarthritis rat group injected with clematidis radix pharmacopuncture at ST36(CR, n=5). The experiment was conducted over a period of 21 days after injecting MIA. We analyzed body weight, hind paw weight distribution, liver and renal function, immunocytes, cykokines, inflammatory mediators, inflammatory proteins and mRNA expressions, as well as histopathological changes. Results : The CR group showed a significant increase in the hind paw weight distribution, and significant decreases in IL-$1{\beta}$, IL-6, $PGE_2$, $LTB_4$, osteocalcin, deoxypyridinoline level, the protein expression of COX2, arachidonate 5 lipoxygenase, and the mRNA expression of COX2, TNF-${\alpha}$, IL-$1{\beta}$, and NOS-II. In terms of the joint damages induced by osteoarthritis, the CR group showed a greater protective effect than group C in histopathologic observation (H&E, Safranin-O staining). Conclusion : These results demonstrated that clematidis radix pharmacopuncture had anti-inflammatory and analgesic effects. In addition, these results showed that it inhibited the progression of osteoarthritis.

• 동의생리병리학회지
• /
• 제18권6호
• /
• pp.1825-1831
• /
• 2004

Phellinus linteus is known as a medicinal mushroom, which has the pharmaceutical activity on tumors and inflammatory diseases in traditional Oriental medicine. However, despite extensive pharmacological studies on P. linteus, the liquor of fermentation using mycelium of P. linteus(LFMP) has not been investigated. In the present study, it was examined the effect of the evaporating extract from LFMP(E-LFMP) on the expression of inflammatory proteins and the generation of reactive oxygen species in human hepatocarcinoma HepG2 cells. E-LFMP inhibited acetaldehyde-induced morphological change in HepG2 cells. Also, E-LFMP inhibits expression of inflammatory proteins including cyclooxygenase(COX)-1 and COX-2 through suppressing nuclear translocation of nuclear factor κB(NF-κB) and degradation of inhibitory κBα(IκBα). In addition, E-LFMP inhibits generation of reactive oxygen species(ROS) by hydrogen peroxide(H₂O₂) in HepG2 cells. These results suggest that LFMP has the pharmaceutical, especially anti-inflammatory, activity similar to P. linteus mushroom.

• 대한약리학회지
• /
• 제22권1호
• /
• pp.51-59
• /
• 1986

Lidocaine의 심근수축력 억제 작용에 관한 기전연구 일환으로 lidocaine에 의해 수축력이 감소된 흰쥐 적출심방에 대한 fructose의 효과를 검토하였다. Fructose는 기질제거에 의해 감소된 적출심방의 수축력을 현저히 증가시켰으며, 30mM에서 최대 증가효과를 나타냈다. Krebs-Ringer glucose용액에 현수한 적출심방의 수축력은 0.1mM lidocaine에 의해 약 50%의 감소를 나타냈으며, 30mM fructose의 투여는 이 감소된 수축력을 현저히 증가 시켰다. Lidocaine 억제심방에 대한 fructose의 실험 성적은 pyruvate나 acetate에서 얻은 실험성적과 유사하였다. 그러나 같은 농도의 fructose는 저 calcium(1/2)농도의 Krebs-Ringer glucose medium에서 감소(약 50% 감소)된 적출심방의 수축력을 증가시키지 못하였다. 이상의 결과에서 lidocaine은 심근내 포도당 대사를 해당과정에서 억제한다는 가능성을 재확인하고 있으며, 나아가서 lidocaine은 해당과정의 phosphofructokinase step 이전의 초기단계에서 억제하고 있을 가능성을 시사하고 있다.

• Journal of Applied Biological Chemistry
• /
• 제50권2호
• /
• pp.78-84
• /
• 2007

The anti-fibrotic effects of hot water extract of adventitious root culture of Panax ginseng (ARCP) and the possible mechanisms were investigated on $CCl_4-induced$ hepatotoxicity model mice. Fibrosis was induced by a mild treatment of $CCl_4$. Then silymarin as a positive control drug and ARCP or carrier alone as a negative control were treated. Serum GPT, GOT and ALP activity levels were lowered by 25, 21 and 11% for silymarin treated group and by 48, 39 and 14% for ARCP treated group compared to carrier treated alone. Hepatic collagen for ARCP treatment group was reduced by 18% and MDA contents decreased a little more. Pro-fibrotic gene ($TGF-{\beta}1$, TIMP-1 and ${\alpha}-SMA$) expression increased following the $CCl_4$ treatment, but both the silymarin and the ARCP treatments decreased the expressions of these genes by 20% to 50%. The antioxidant effect of ARCP was studied by DPPH free radical scavenging activity. In addition, a generation of reactive oxygen species (ROS) was also reduced in $H_2O_2-treated$ HepG2 cells upon the ARCP treatment. In summary, ARCP has antioxidant property, and can have some protection against oxidative stress; more importantly, ARCP can efficiently protect mice against $CCl_4-induced$ fibrosis.

• 한국환경보건학회지
• /
• 제10권1호
• /
• pp.13-20
• /
• 1984

The hospital wastewaters have to be so disposed as to prevent disease and to protect water resources from hazardous substances disinfectants, medicines, and chemicals. Polyvinylpyrrolidone-iodine complex (povidone-iodine) is widely used in the hospital as one of disinfectants. This study was carried out to manifest the effect of disinfectants in growth of activated sludge in treatment of the hospital wastewater by the activated sludge process. The results are as follow. 1. An average water quality of the hospital wastewater showed 7.2 in pH, 3.2 ppm in DO, 293.3 ppm in SS, 96.0 ppm in BOD, 151.1 ppm in COD, 0.4 ppm in povidone-iodine, 0.5 ppm in phenols, 5.4 ppm in surfactants, 1.6 ppm in o-phosphate, 4.6 ppm in $NH_3-N, 249\times 10^4$ counts/100 ml in coliform group organisms, and $1,369\times 10^2$ counts/ml in general counts of bacteria. And wastewater amounts discharged per bed was calculated 70 l/d/bed. 2. In batch culture activated sludge process, each of cresol and povidone-iodine was not effected in less than 0.1 ppm concentration, but the more concentration, the more inhibit the growth rate of activated sludge. In the mixture of two disinfectants, the growth was more inhibited the effect of single disinfectants. So that this reaction is considered as addition effect of two disinfectants. 3. The removal rates of the disinfectants-by continuous culture activated sludge process were 77.6% in 0.4 ppm povidone-iodine, and in BOD was 85.6%. 4. It is desirable that the hospital wastewater is planed in order to be discharged to two system separately, sewer from life system and wastewater from medical system. From those results, it has been concluded that the hospital wastewater has to be treated safely by the activated sludge process.

• 한국지역사회생활과학회지
• /
• 제15권1호
• /
• pp.67-76
• /
• 2004

In order to promote the value of the flowers as new agricultural products, we investigated the biological activities of rape, arrowroot, and rose extracts. Biological activities investigated included antioxidant activity and the effects on 3T3-L1 fibroblast cells. When each flower was extracted with methanol, the antioxidant index and electron donating activity of roses was the highest $(IC_{50}$ of rose extract was $17.6 \mu{g}/m\ell$). When 3T3-L1 fibroblast cells were treated with extracts made with hexane, ethyl acetate, and ether, the rape extracts had a cytotoxic effect on the cells. 12.2% of cells survived when treated with a 3mg/$m\ell$ ether extract while those treated with the same concentration of hexane and ethyl acetate had survival rates of 76.2% and 78.6% respectively. In contrast to rape, the ether extract of arrowroot and rose stimulated the growth of 3T3-L1 cells. The effect of rose extracts was much bigger than those of other extracts. Although every rose extract stimulated the growth of the 3T3-L 1 cells, the ether extract stimulated growth up to 168.6% compared to the control at the concentration of $0.3mg/m\ell$, and 148.3% at the concentration of $1mg/m\ell$. The toxicity on cells treated with $H_2 O_2$ of $450\mu{M}l$was decreased with the addition of rose extract. The survival rate after treatment with rose extract at the concentration of $100\mu{g}/m\ell$ was increased to 71% compared to the 32% survival rate of control. From these results, it can be concluded that the extracts of arrowroot and rose seem to stimulate cells, whereas the extract of rape has a cytotoxic effect. Biological activities of ether extract were the strongest compared to those of other extracts at the tested concentrations.