Various supercritical carbon dioxide cycle layouts study for molten carbonate fuel cell application

Bae, S.J.,Ahn, Y.,Lee, J.,Lee, J.I. Elsevier Sequoia 2014 Journal of Power Sources Vol.270 No.-

Various supercritical carbon dioxide (S-CO<SUB>2</SUB>) cycles for a power conversion system of a Molten Carbonate Fuel Cell (MCFC) hybrid system are studied in this paper. Re-Compressing Brayton (RCB) cycle, Simple Recuperated Brayton (SRB) cycle and Simple Recuperated Transcritical (SRT) cycle layouts were selected as candidates for this study. In addition, a novel concept of S-CO<SUB>2</SUB> cycle which combines Brayton cycle and Rankine cycle is proposed and intensively studied with other S-CO<SUB>2</SUB> layouts. A parametric study is performed to optimize the total system to be compact and to achieve wider operating range. Performances of each S-CO<SUB>2</SUB> cycle are compared in terms of the thermal efficiency, net electricity of the MCFC hybrid system and approximate total volumes of each S-CO<SUB>2</SUB> cycle. As a result, performance and total physical size of S-CO<SUB>2</SUB> cycle can be better understood for MCFC S-CO<SUB>2</SUB> hybrid system and especially, newly suggested S-CO<SUB>2</SUB> cycle shows some success.

Bifidobacterium bifidum ATCC 11863 에 의한 우유의 발효에 관한 연구 - 발효에 의한 유성분의 변화 -

고준수(J . S . Goh),권일경(I . K . Kwon),안종건(J . K . Ahn),윤영호(Y . H . Yoon) 한국축산학회 1988 한국축산학회지 Vol.30 No.10

This research was performed to get the informations needed to manufacture fermented milk products using bifidobacteria as starter culture. The conversion of constituents in the whole milk fermented by Bifidobacterium bifidum ATCC 11863 was investigated, and the results were compared with those by several lactic acid bacteria generally used for the fermented milk products. 1. The use of lactose varied according to the kinds of bacteria, such as B. bifidum, L. acidophilus, L. casei and S. thermophilus. When the whole milk was fermented by B. bifidum, the glucose reached 480 mg per 100 ml; while galactose reached 661 mg per 100 ml when S. thermophilus was grown in whole milk. 2. B. bifidum and L. acidophilus raised the, soluble nitrogenous compounds in whole milk after 24 hours at 37℃, however, there was little change soluble nitrogenous compounds content of whole milk by L. casei and S. thermophilus. 3. The content of free amino acids was increased by B. bifidum and L. acidophilus after 24 hours at 37℃; whereas decreased when L. casei and S. thermophilus were grown. 4. The polyacrylamide gel electrophoresis evidenced no significant change of casein but distinct changes of whey protein were observed by B. bifidum, L. acidophilus, L. casei and S. thermophilus at 37℃ after 24 hours. The change of whey protein was more noticeable when whole milk was fermented by L. acidophilus and L. casei than by B. bifidum and S. thermophilus. 5. The pyruvic acid content was decreased in whole milk after 24 hours at 37℃ by B. bifidum, L. acidophilus, L. casei and S. thermophilus. Lactic and succinic acid were produced during the fermentation of whole milk by B. bifidum, L. acidophilus and L. casei but B. bifidum produced less lactic acid than other bacteria. 6. Acetic acid was increased in the whole milk by B. bifidum, L. acidophilus and L. casei after 24 hours at 37℃. It was increased more rapidly by B. bifidum than by other bacteria; however, it was decreased during the fermentation by S. thermophilus. When B. bifidum was grown in whole milk, volatile organic acids such as propionic, isobutyric, butyric, isovaleric, valeric and caproic acids were decreased.

Predicting temporal shifts in the spring occurrence of overwintered Scotinophara lurida (Hemiptera: Pentatomidae) and rice phenology in Korea with climate change

Lee, H.,Kang, W. S.,Ahn, M. I.,Cho, K.,Lee, J. H. Springer Science + Business Media 2016 International journal of biometeorology Vol.60 No.1

<P>Climate change could shift the phenology of insects and plants and alter their linkage in space and time. We examined the synchrony of rice and its insect pest, Scotinophara lurida (Burmeister), under the representative concentration pathways (RCP) 8.5 climate change scenario by comparing the mean spring immigration time of overwintered S. lurida with the mean rice transplanting times in Korea. The immigration time of S. lurida was estimated using an overwintered adult flight model. The rice transplanting time of three cultivars (early, medium, and medium-late maturing) was estimated by forecasting the optimal cultivation period using leaf appearance and final leaf number models. A temperature increase significantly advanced the 99 % immigration time of S. lurida from Julian day 192.1 in the 2000s to 178.4 in the 2050s and 163.1 in the 2090s. In contrast, rice transplanting time was significantly delayed in the early-maturing cultivar from day 141.2 in the 2000s to 166.7 in the 2050s and 190.6 in the 2090s, in the medium-maturing cultivar from day 130.6 in the 2000s to 156.6 in the 2050s and 184.7 in the 2090s, and in the medium-late maturing cultivar from day 128.5 in 2000s to 152.9 in the 2050s and 182.3 in the 2090s. These simulation results predict a significant future phenological asynchrony between S. lurida and rice in Korea.</P>

Elliptic flow of identified hadrons in Pb-Pb collisions at s N N = 2.76 $$ \sqrt{s_{\mathrm{NN}}}=2.76 $$ TeV

Abelev, B.,Adam, J.,Adamová,, D.,Aggarwal, M. M.,Agnello, M.,Agostinelli, A.,Agrawal, N.,Ahammed, Z.,Ahmad, N.,Ahmed, I.,Ahn, S. U.,Ahn, S. A.,Aimo, I.,Aiola, S.,Ajaz, M.,Akindinov, A.,Alam, S. Institute of Physics Pub 2015 The journal of high energy physics Vol.2015 No.6

<P>The elliptic flow coefficient (v(2)) of identified particles in Pb-Pb collisions at root s(NN) = 2.76 TeV was measured with the ALICE detector at the Large Hadron Collider (LHC). The results were obtained with the Scalar Product method, a two-particle correlation technique, using a pseudo-rapidity gap of |Delta eta| > 0.9 between the identified hadron under study and the reference particles. The v (2) is reported for pi(+/-), K-+/-, K-S(0), p+(p) over bar, phi, Lambda+(Lambda) over bar, Xi+(Xi) over bar (+) and Omega(-)+(Omega) over bar (+) in several collision centralities. In the low transverse momentum (p(T)) region, p(T) < 3 GeV/c, v(2)(p(T)) exhibits a particle mass dependence consistent with elliptic flow accompanied by the transverse radial expansion of the system with a common velocity field. The experimental data for pi (+/-) and the combined K-+/- and K-S(0) results, are described fairly well by hydrodynamic calculations coupled to a hadronic cascade model (VISHNU) for central collisions. However, the same calculations fail to reproduce the v(2)(p(T)) for p+(p) over bar, phi, Lambda+(Lambda) over bar, Xi+(Xi) over bar (+). For transverse momentum values larger than about 3 GeV/c, particles tend to group according to their type, i.e. mesons and baryons. The present measurements exhibit deviations from the number of constituent quark (NCQ) scaling at the level of +/- 20% for p(T) > 3 GeV/c.</P>

RBFN과의 Hybrid알고리즘에 의한 음소인식

안종영,박창호,김상범,김주성,김수훈,허강인 동아대학교 공과대학 부설 한국자원개발연구소 1995 硏究報告 Vol.19 No.2

A feed forward neural network has been used for the pattern classification. It has the capability of representing a desired input-output mapping through the training of a given set of teaching patterns. In this paper, we proposed recognition by GPFN and PNN a kind of RBFN. The neural network can approximate a posteriori probability through Bay's theorm, by training it with binary vectors as target pattern corresponding to the categroies of input pattern. In the phoneme recognition, we compared the recognition rate of GPFN, PNN with Hybrid(VQ, LVQ) Algorithm. We found that recognition rate of LVQ-PNN, VQ-PNN had higher then that of them.

BSO 유도 루타치온 저감 흰쥐에서 1, 2, 4-trichlorobenzene의 급성독성에 관한 연구

안영수,권명희,이정섭,김정우,김대선,류홍일,강인구 한국환경독성학회 1996 환경독성보건학회지 Vol.11 No.1

1, 2, 4-Trichlorobenzene (1, 2, 4-TCB) is used as a dye carrier, as an intermediate in the synthesis of herbicides, as a flame retardant, and for other purpose. After a single oral administration of 1, 2, 4-TCB (200 mg/kg, 400 mg/kg) in rats, toxic effects were studied by means of serum biochemical and heatological analysis, and liver calcium concentration. Administration of 1, 2, 4-TCB resulted in dose-dependent liver and kidney damage as estimated by increased serum alanine aminotransferase (ALT) activities, liver calcium concentration and blood urea nitrogen (BUN). Pretreatment with DL-buthionine sulfoximine (BSO, 2 mmol/kg, i. p. ) considerably decreased liver glutathione concentration, which was accompanied by markedly elevated serum ALT activates. It is well-known that toxicity of halogenated benzene such as bromobenzene, 1, 4-dichlorobenzene is increased by pretreatment of henobarbital (PB), and protected by pretreatment of cytochrome P450 inhibitor including metyrapone (MP). However, there was no obvious alterations in toxicity of 1, 2, 4-TCB by pretreatment of phenobarbital or metyrapone. In comparison with control group, treatment groups exhibited significant changes in some parameters of hematological analysis but all hematological values remined within normal ranges.

肝吸蟲症의 疫學

金東燦(D. C. Kim),李溫永(O. Y. Lee),李鐘秀(Lee, J. S.),安壯洙(J. S. Ahn),張泳美(Y. M. Chang),孫盛昌(S. C. Son),文翊相(I. S. Moon) 한국농촌의학 지역보건학회 1983 농촌의학·지역보건 Vol.8 No.1

The plant-specific uncertainty analysis for an ex-vessel steam explosion-induced pressure load using a TEXAS-SAUNA coupled system

Ahn, K.I.,Park, S.H.,Kim, H.D.,Park, H.S. North-Holland Pub. Co 2012 Nuclear engineering and design Vol.249 No.-

An ex-vessel steam explosion has been considered as one of the most challenging severe accident phenomena to the integrity of the reactor cavity and containment of a nuclear power plant, owing to its rapid and dynamic characteristics. The purpose of this paper is to provide plant-specific uncertainty analysis results on the ex-vessel steam explosion-induced pressure loads, which can be used as key input to assess the conditional failure probability if the fragility structures of interest is provided. The APR1400, a two-loop pressurized water reactor, has been selected as a reference plant for an uncertainty analysis. For this purpose, a comprehensive uncertainty analysis has been performed for key thermal-hydraulic conditions of the reactor pressure vessel and cavity, which can highly influence on these pressure loads, with the help of a coupling of a steam explosion analysis code (TEXAS-V) with a sampling-based uncertainty quantification code (SAUNA). To get a more robust conclusion based on the analysis results, various sensitivity analyses have been applied to both probability types (e.g., normal and uniform PDF) and sampling schemes (e.g., random and Latin Hypercube sampling). Key contributors (i.e., physical and model parameters) to the underlying pressure loads have been determined by assessing the six currently available types of importance measures.

Sub-Halfmicron Processing Optimization by Constant Enhancement Lithography for I-Line

Moon, S. C.,Kim, K. Y.,Kim, Y. I.,Lee, Y. S.,Ahn, D. J.,Oh, K. H. 대한전자공학회 1991 ICVC : International Conference on VLSI and CAD Vol.2 No.1

In recent days, a device manufacturing technology for pattern delineation is beyond the capability of single layer resist(SLR) process with optical lithography, especially in the sub-halfmicron region. Contrast Enhanced Lithography (CEL) is a effective technique which improves decreased light contrast through the lens. In this paper, water-soluble CEL process for I-line has been developed to overcome the limitations of a standard single layer resist process. This process extended the practical resolution capability into the sub-halfmicron region by increasing effective depth of focus while maintaining vertical resist profiles. To analyze CEL process characteristics, we investigated general features such as sensitivity contrast, resolution capability, focus latitude, and proximity effects compared to standard single resist process using a 5× reduction 1-line wafer stepper with 0.50 NA lens.

Temperature-dependent current-voltage characteristics of Er-silicide Schottky contacts to strained Si-on-insulator

Jyothi, I.,Seo, M.W.,Janardhanam, V.,Shim, K.H.,Lee, Y.B.,Ahn, K.S.,Choi, C.J. Elsevier Sequoia 2013 Journal of alloys and compounds Vol.556 No.-

We fabricated Er-silicide (ErSi<SUB>1.7</SUB>) Schottky contacts to strained Si-on-insulator (sSOI) with a strain level of 0.77% and investigated their electrical properties in the temperature range of 225-400K. The Schottky parameters such as the barrier height, ideality factor, and series resistance were found to strongly depend on temperature. Barrier height and ideality factor were found to decrease and increase, respectively, with decreasing temperature. The series resistance gradually increased with decreasing temperature. A discrepancy between the Schottky barrier heights calculated from the forward current-voltage (I-V) characteristics and Norde's method indicated a deviation from the ideal thermionic emission of ErSi<SUB>1.7</SUB>/sSOI Schottky diode. The lateral inhomogeneity of the Schottky barrier and potential fluctuations at the interface between ErSi<SUB>1.7</SUB> and sSOI could be a main cause of the difference between the calculated and theoretical values of the Richardson constant. On the basis of a thermionic emission mechanism with a Gaussian distribution of the barrier heights, temperature dependency of ErSi<SUB>1.7</SUB> Schottky contact to sSOI was explained in terms of the barrier height inhomogeneities at the interface.