• 한국세라믹학회지
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• 제31권4호
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• pp.407-414
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• 1994

Compacts were prepared using the SHS(Self-propagating High-temperature Synthesis) method and nitrided at temperatures range from 145$0^{\circ}C$ to 175$0^{\circ}C$, and pressed at 180$0^{\circ}C$ under N2 atmosphere. The samples were characterized for bulk density, porosity, pore size and distribution, phase composition, microstructure and fracture toughness. Compacts were composed of whiskers, which showed a good candidate for the composite materials. The major phases of the compacts nitrided at 175$0^{\circ}C$ and pressed at 180$0^{\circ}C$ were 15R-sialon with a large aspect ratio.

• 약학회지
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• 제50권1호
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• pp.1-7
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• 2006

The purpose of the present study was to formulate the aqueous solution of 1-cyclopent-3-enylmethyl-6(3,5-dimethyl-benzoyl)-5-ethyl-1H-pyrimidine-2,4-dione (CPD), a novel antivirus compound containing pirimidine structure. For this purpose, the effects of various solubilization agents such as cosolvents [ethanol, propylene glycol (PG), polyethylene glycol 300 (PEG 300), polyethylene glycol 400 (PEG 400), glycerin], surfactants (Tween 80, Cremophor$^{(R)}$ RH40, Cremophor$^{(R)}$ EL, Poloxamer 407, Poloxamer 188) and a complexation agent [hydroxypropyl-${\beta}$-cyclodextrin (HPBCD)] , on the solubility of CPD in aqueous solution were evaluated. The solubility of CPD in water was under $1\;{\mu}g/ml$ at $20^{\circ}C$. Cosolvents such as ethanol, PG, PEG 300, PEG 400 and glycerin did not enhance the solubility of CPD at the $0{\sim}40\%$ concentration range. The solubility of CPD was significantly elevated by the addition of cosolvents over the $80\%$ concentration range. On the other hand, tween 80, Cremophor$^{(R)}$ L, Cremophor$^{(R)}$ RH40, and HPBCD showed enhanced effects on the solubility of CPD. The enhanced effects of Poloxamer 407 or Poloxamer 188 on the CPD solubility were less pronounced compared with tween 80, Cremophor$^{(R)}$ L or Cremophor$^{(R)}$ RH40. As a results, tween 80 aqueous solution was selected as an optimum solvent system. The aqueous solutions containing $20\%$ tween 80 were formulated as a dosing solution containing CPD for its intraperitoneal and intrahypodermic administration, respectively, The formular showed physical stability after stored for 7 days at $4^{\circ}C$.

• KSBB Journal
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• 제26권5호
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• pp.407-411
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• 2011

Microbial fuel cell (MFC) wes enriched using sludge in wastewater treatment. The microbial community of activated sludge and enriched MFC were analyzed by FISH (fluorescent in situ hybridization) and 16S rDNA sequencing. Bacteroidetes group were pre-dominant in activated sludge by FISH. ${\alpha}$ group, ${\gamma}$ group and Acintobacter group were dominant and they were similar to distribution. The average value of 10 peak of MFC is 0.44C. When MFC wase enriched by sludge, ${\gamma}$-Proteobacteria, Plantomycetes group increased 70% and 60%, respectively. In results of 16S rDNA sequencing, Sphiringomonas sp. was comprised in ${\alpha}$ proteobacteria and Enterobacter sp., Klebsiella sp., Acinetobacter sp., Bacillus sp. were comprised in ${\gamma}$ proteobacteria and Chryseobacterium sp. was comprised in Flavobacteria were isolated from sludge.

• 한국수소및신에너지학회논문집
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• 제32권5호
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• pp.356-364
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• 2021

During the hydrogen fueling process, hydrogen temperature inside the compressed tank were limited below 85℃ due to the allowable pressure of tank material. The chiller system to cool compressed hydrogen used R407C, greenhouse gas with a high global warming potential (GWP), as a refrigerant. To reduce greehouse gas emission, it should be replaced by refrigerant with a low GWP. This study proposes a chiller system for fueling hydrogen with R290, consisted in propane, by applying the C3 pre-cooled system use d in the LNG liquefaction process. The proposed system consisted of hydrogen compression and cooling sections and optimized the operating pressure through exergy analysis. It was also compared to the exergy efficiency with the existing system at the optimal operating pressure. The result showed that the optimal operating pressure is 700 kPa in 2-stage, 840 kPa/490 kPa in 3-stage, and the exergy efficiency increased by 17%.

• 한국동물위생학회지
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• 제37권2호
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• pp.85-96
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• 2014

Total 99 strains of Campylobacter spp. were isolated from 117 cases of duck's fecal samples. Among 99 strains of Campylobacter spp. isolates, 93 strains (93.9%) were C. jejuni and 6 strains (6.1%) were C. coli. Prevalence of virulence and GBS associated genes of 72 C. jejuni isolates was determined by m-PCR. Among the 10 kinds of virulence associated genes, cadF, dnaJ, flaA and ceuE genes were detected in all of C. jejuni isolates from ducks, racR, pldA, iamA, ciaB, virB11 and docC genes were 87.5%, 84.7%, 77.8%, 48.6%, 13.9% and 11.1%, respectively. Antimicrobial susceptibility test was performed on 72 C. jejuni isolates. The rate of resistance were 62.5% for oxytetracycline, 55.6% for kanamycin, 54.2% for enrofloxacin, 50% for ciprofloxacin, 37.5% for tetracycline and nalidixic acid, 18.1% for ampicillin, 15.3% for streptomycin, and 6.9% for ofloxacin. All isolates were susceptible to erythromycin. The adherence (intracellular and extracellular bacteria) abilities of the 20 isolates to INT-407 cells were between $4.21{\pm}1.27{\times}10^4$ CFU/well and $1.053{\pm}0.451{\times}10^6$ CFU/well from the isolates of cj-55 and cj-52, respectively, and that can be expressed as 0.1033% to 5.2655% to the infecting inoculum. The invasion (intracellular bacteria) abilities of the 20 isolates to INT-407 were between $1.00{\pm}1.73{\times}10^3$ CFU/well and $8.47{\pm}5.16{\times}10^4$ CFU/well from the isolates of cj-13 and cj-47, respectively, and that can be expressed as 0.0050% to 0.4235% to the infecting inoculums. The average CFU/well of 20 campylobacters isolated from ducks for adherence to and invasion were $2.646{\pm}2.886{\times}10^5$ and $3.03{\pm}2.7{\times}10^4$ respectively, and that was $1.3230{\pm}1.2139%$ and $0.1516{\pm}0.1343%$ of the starting viable inoculum. There was considerable correlation ($R^2$=0.627) between the adherence and invasion ability of C. jejuni isolates for INT-407 cell.

• 대한수학회논문집
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• 제37권2호
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• pp.399-407
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• 2022

In this paper, we continue to study the von Neumann regularity of rings whose essential maximal right ideals are GP-injective. It is proved that the following statements are equivalent: (1) R is strongly regular; (2) R is a 2-primal ring whose essential maximal right ideals are GP-injective; (3) R is a right (or left) quasi-duo ring whose essential maximal right ideals are GP-injective. Moreover, it is shown that R is strongly regular if and only if R is a strongly right (or left) bounded ring whose essential maximal right ideals are GP-injective. Finally, we prove that a PI-ring whose essential maximal right ideals are GP-injective is strongly π-regular.

• 정보처리학회논문지B
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• 제14B권6호
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• pp.407-412
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• 2007

초음파 의료 영상기기나 산업용 초음파 검사 시스템의 성능은 초음파 탐촉자의 성능에 의해 크게 좌우된다. 탐촉자의 성능 특성 정보는 보통 제작자가 제공하는 반사원의 초음파 R/F 신호와 주파수 특성에 의해 기술된다. 그러나 집속형 초음파 탐촉자의 경우, 두 자료로는 선명한 C-Scan 이미지를 얻을 수 있다는 것을 보증할 수는 없다. 그래서 집속형 초음파 탐촉자의 성능 평가를 위한 새로운 척도로 상대 초점크기 및 상대 유효초점영역의 모양을 제안한다. 상대 초점의 크기와 상대 유효초점영역의 모양은 쇠구슬로부터 획득된 초음파 R/F 신호를 가상 3차원 영상 복원 프로그램으로 처리하여 얻는다. 제시된 방법은 기존 자료로는 알 수 없었던 탐촉자 성능을 정확히 평가할 수 있었으며, 방법도 간단하여 실제 탐촉자 제작시 불/양품을 쉽게 가려 낼 수 있으며, 탐촉자 경년열화에 따른 성능 저하도 검출할 수 있는 장점을 갖는다. 결과적으로 초음파 영상기기나 산업용 초음파 검사 시스템의 성능을 담보할 수 있다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권9호
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• pp.1027-1031
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• 2014

외기냉수냉방 시스템은 공조나 산업공정에 사용되는 냉수를 저온의 외기를 이용하여 냉각하는 시스템으로 에너지를 절감하기위해 사용되며, 냉각시스템과 외기와 냉수가 열교환을 하는 드라이쿨러로 구성되어있다. 외기냉수냉방 시스템은 지속적인 냉방이 필요한 곳에 에너지절감효과가 뛰어나나 국내의 경우, 외기냉수냉방 시스템에 설계 기준과 자료가 미비하다. 따라서 본 연구에서는 상용프로그램 HYSYS를 이용하여, 드라이쿨러를 이용한 외기냉수냉방 시스템의 요소변화에 따른 성능을 비교 분석했으며 그 결과는 다음과 같다. 드라이쿨러의 냉각능력은 외기온도, 요구냉수온도, 열교환기의 LMTD (Logarithmic Mean Temperature Difference, 대수평균온도차)에 따라 변한다. 드라이쿨러는 외기온도가 낮을 수록 그 냉각능력이 증가하며, LMTD가 낮은 드라이쿨러가 LMTD가 높은 것에 비하여 고온의 외기온도에서 사용이 가능하였다. 외기온도가 극히 낮은 지역에서는 글리콜이 함유된 부동액을 사용해야하며 국내의 외기온도를 고려하였을 때, 글리콜농도 34%의 부동액이 적절한 것으로 판단된다. 냉동기에 적용될 작동유체의 경우, R22, R134a, R407C의 압축일을 비교했으며, R134a가 환경관련 규제와 에너지 사용측면에서 우수한 냉매로 사료된다.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2008년도 추계학술발표논문집
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• pp.407-410
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• 2008

원소분석 결과 평균값은 "화합물 및 화학제품 제조업"의 경우 C 33.06wt%, H 4.34wt%, O 24.81wt%, N 5.18wt%, S 0.72wt%로 나타났으며, "코크스, 석유 정제품 및 핵연료 제조업"의 경우 C 36.58wt%, H 4.74wt%, O 26.79wt%, N 5.09wt%, S 0.49wt%로 나타났다. 열중량분석 결과, B사에서 배출되는 슬러지는 $700^{\circ}C$ 이상에서 그리고 F와 N 사에서 배출되는 슬러지는 $600^{\circ}C$ 정도의 온도에서도 연소가 가능할 것으로 판단된다. 연소테스트 결과, 산화반응과 동시에 열분해 반응이 일어나 고농도의 일산화탄소가 배출된다.

• 분석과학
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• 제23권1호
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• pp.68-73
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• 2010

Cimetidine HCl 함유 주사액에 대한 네모파 전압전류법(SWV) 분석방법을 개발 하고자 인산염 완충용액(pH 3.01~8.97)을 지지전해질로 하여 $5.00{\times}10^{-4}\;M$의 cimetidine HCl용액에 대하여 SWV를 실행한 결과 cimetidine의 구조 내 -C=N-C$\equiv$N-의 전기화학적 환원으로 추정되는 하나의 환원 봉우리는 Ep가 -0.051V/pH씩 이동하여 수소가 관여함을 나타내었다. Cimetidine HCl을 정량분석 하기 위하여 세 가지 인산염 완충용액을 지지전해질로 하여 농도범위 $1.00{\times}10^{-5}\;M\sim5.00{\times}10^{-3}\;M$에서 검량곡선을 작성할 때 기울기는 127,407nA/M(pH 3.01), 115,125nA/M(pH 5.00) 및 111,287nA/M(pH 7.00)이었으며, 상관계수 $R^2$값$\geqq$0.9997의 좋은 직선 성을 나타내었다. 타그마주$^{(R)}$ 앰플을 표준물 첨가법으로 SWV 정량분석 할 때 하루 중 정밀도(n=4)는 분석시료 제조당일에 1 앰플 당 cimetidine의 함량이 $203{\pm}3.8mg$(규정된 함량의 102%)으로 RSD 1.9%로 나타났으며, 5일에 걸친 날짜 간 정밀도(n=4)는 1.3%이내의 RSD를 보여 정밀도가 합리적이었다.