• 자원ㆍ환경경제연구
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• 제15권5호
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• pp.799-826
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• 2006

본 연구에서는 시계열분석기법과 그래프 이론을 활용하여 8개의 북미천연가스 현물시장간의 관계를 분석하였다. 벡터오차수정모형과 탐욕동급검색 알고리즘(Greedy Equivalence Search Algorithm)을 활용한 그래프 이론을 통해 시장간의 관계를 분석한 결과, 가격발견과정은 초과수요지역에서 발생하여 초과공급지역으로 진행되는 것으로 나타났다. 북미 천연가스 현물시장 중에서 시카고로 대표되는 미국의 중서부지역이 가격발견과정에 있어 가장 중요한 시장인 것으로 나타났으며 미국 동부지역에 있어 펜실바니아의 Ellisburg-Leidy Hub이, 그리고 미국서부지역에 있어서는 Malin Hub이 가격발견과정에 있어 중요한 시장인 것으로 나타났다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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• pp.405-410
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• 1994

The purpose of this paper is to present the details of design procedure of a nonlinear regulator by Riemannian geometric approach and to applied it to the case of a double-effect evaporator. A nonlinear geometric model is proposed on a direct sum space of a state vector and a control vector as well as in the previous parers by the authors. The geometric model is derived by replacing the orthogonal straight coordinate axes of a linear system on the direct sum space with the curvilinear coordinate axes. The integral manifold of the geometric model becomes homeomorphic to that of fictitious linear system. For the geometric model a nonlinear regulator with a performance index is designed renewedly by the procedure of optimization. The construction method of the curvilinear coordinate axes on which the nonlinear system behaves as a linear system is discussed. To apply the above regulator theory to double-effect evaporators especially to the pilot plant at the University of Alberta, a suitable nonlinear model is determined by the plant dynamics. The optimal control law is derived through the calculation of the homeomorphism. As a result it is confirmed that the regulator is effective and superior to that of the conventional control.

• 한국결정학회지
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• 제14권2호
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• pp.79-83
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• 2003

Electrolytic MnO₂ (EMD)의 미세구조를 X선 회절 및 투과전자현미경 분석을 통해 연구하였다. 벌크에 대한 X선 회절 실험은 전헝적인 EMD 재료의 분말 회절패턴을 나타내었다. 투과전자현미경 분석은 EMD가 약 0.2㎛크기의 입자로 이루어져 있고, 각각의 입자가다시 10 nm 정도의 결정립으로 이루어진 이중 미세구조를 가짐을 나타내었다. 나노 결정립에 대한 전자빔 마이크로 회절 분석 결과, EMD 입자는 여러 상의 혼합체로서 약 50%의 Ramsdellite, 30%의 ε-MnO₂, 15%의 Pyrolusite 상으로 이루어져 있음을 확인하였다. 한편, X선 분말 회절패턴 상의 약 67°에 위치한 ｛1120｝ 피크와 (0001) 면에 대한 고분해능 이미지는 ε-MnO₂ 상의 존재를 입증하였다.

• 천문학회보
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• 제41권2호
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• pp.31.3-32
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• 2016

We present the radial variations of the scale heights and the vertical velocity dispersions in a sample of nearby edge-on galaxies using BIMA/CARMA $^{12}CO$ ($J=1{\rightarrow}0$), VLA/EVLA HI, and Spitzer $3.6{\mu}m$ data. Both the disk thicknesses and the velocity dispersions of gas and stars vary with radius, contrary to assumptions of previous studies. We investigate how the interstellar gas pressure and the gravitational instability parameter differ from values derived assuming constant velocity dispersions and scale heights. Using the measurement of the disk thicknesses and the derived radial profiles of gas and stars, we estimate the corresponding volume densities. The gravitational instability parameter Q follows a fairly uniform profile with radius and is ${\geq}1$ across the star-forming disk. The star formation law has a slope that is significantly different from those found in more face-on galaxy studies. The midplane gas pressure appears to roughly hold a power-law correlation with the midplane volume density ratio (${\rho}_{H2}/{\rho}_{HI}$).

• Asian-Australasian Journal of Animal Sciences
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• 제18권6호
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• pp.795-801
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• 2005

Eighteen Suffolk wether lambs (BW = 24 kg) were chronically exposed to temperatures of cold (2$^{\circ}C$) or warm (22$^{\circ}C$). The experimental design consisted of a 2${\times}$3 factorial with a single crossover of environment treatment. The sheep were closely shorn and were housed in individual metabolic crates in controlled environment rooms. Sheep consumed pelleted diets ad libitum, which consisted of mainly barley grain and brome grass, and diets contained 7, 11 or 14% crude protein (CP). Animals were catheterized via one jugular vein with a PVC catheter and received a single injection of 60-65 Ci of $^{14}$C]urea. Plasma urea-N (PUN), urinary urea (UU), and carbon specific radioactivity were measured. Urea metabolism was not affected by environment. Percent urea recycling and urea space clearance were highest (p<0.05) on the low nitrogen diet. Urea pool was increased (p<0.10) for the 14% CP diet. Both UU and PUN concentration were positively related (p<0.01) with diet CP content. Therefore, dietary CP content significantly influenced urea metabolism, however, cold exposure did not alter those parameters.

• Asian-Australasian Journal of Animal Sciences
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• 제4권4호
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• pp.369-375
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• 1991

A series of in vitro incubation studies with washed rumen bacteria were conducted to determine the influence of incubation time and concentrations of peptides, alanine, ammonia nitrogen and carbohydrate on the rate of peptide disappearance and on bacterial growth. Disappearance rate of tri-alanine (ala3) under various conditions was between 30.6 and $58.2mg\;hr^-$ per gram bacterial dry matter. Ala3 was removed from the incubation medium in an almost linear fashion as incubation time and ala3 concentration was increased. Washed rumen bacteria utilized ala3 faster than di-l-alanine (ala2) at all concentrations. Adding 9mM carbohydrate significantly increased ala3 disappearance, but level of ammonia nitrogen had no influence on ala3 disappearance. The presence of alanine in the medium significantly lowered ala3 utilization by rumen bacteria. Bacterial dry matter and nitrogen growth yield were not influenced by alanine and peptides when incubation medium already contained a sufficient level of ammonia nitrogen. Increased ammonia nitrogen in the presence of ala3 did not stimulate bacterial growth. Carbohydrate significantly increased bacterial dry matter and nitrogen growth as expected. Results indicate that the rate of peptide utilization by rumen bacteria may be altered by type and concentration of peptides, and energy supply, and this may be mediated through changes in numbers and type of bacteria.

• Asian Pacific Journal of Cancer Prevention
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• 제17권1호
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• pp.439-443
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• 2016

Background: To assess the effect of an information leaflet on the level of Chinese youth's knowledge about hepatitis B and hepatocellular carcinoma (HCC), the most common type of primary liver cancer (PLC). Materials and Methods: A total of 500 students, from two universities in the Chaoshan area of China, were randomly divided into an intervention group of 280 participants and a control group of 220. Baseline knowledge of HCC and hepatitis B was evaluated by questionnaire interview. Subsequently, only the intervention group was given an information leaflet of HCC and hepatitis B. Three months later, the two groups were contacted for a second interview. Changes in knowledge from baseline of HCC and hepatitis B were compared between the two groups. Results: There was no statistically significant difference in mean PRE-questionnaire scores between the intervention and control groups. However, the mean POST-questionnaire score was significantly higher in the intervention group after the intervention. The leaflet had the greatest effect on the participants' questionnaire score, and raised their level of knowledge about HCC and hepatitis B. Conclusions: The information leaflet intervention is significantly effective in improving the knowledge of HCC and hepatitis B among the youth.

• Asian-Australasian Journal of Animal Sciences
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• 제3권1호
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• pp.1-6
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• 1990

The objective of this experiment was to compare the effect of pH-regulated alkaline hydrogen peroxide (AHP) treatment of rice straw with those of sodium hydroxide (NaOH) and anhydrous ammonia ($NH_3$) treatments on in sacco digestivility. Three non-lactating ruminally cannulated Holstein cows were fed a diet containing 90% forage and 10% concentrate on a dry matter (DM) basis. The AHP treatment significantly (p<0.05) reduced acid detergent lignin content of the straw, resulting in significant (p<0.05) increase of neutral detergent fiber (NDF), acid detergent fiber (ADF) and cellulose concentrations. Disappearance rates of DM and NDF of the straw significantly (p<0.05) increased at the incubation time of 24 h. On the other hand, those of ADF and cellulose were significantly (p<0.05) higher at the incubation time of 12 h than those of the others. The effective degradability of DM(EDDM), NDF(EDNDF), ADF(EDADF) and cellulose (EDCE) were determined using in sacco nylon bag technique on the basis of 0.05/h solid outflow rate. The greater differences (p<0.05) of EDDM, EDNDF, EDADF and EDCE were found between AHP treated straw and the others. In general, AHP treatment of the straw recorded higher digestion coefficients than untreated straw as well as NaOH and $NH_3$ treated straws. The results of this study demonstrate that AHP treatment can be used as a effective method for improving the nutritive value of rice straw for ruminants.

• Journal of Microbiology and Biotechnology
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• 제18권12호
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• pp.1884-1889
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• 2008

The ${\beta}$-lactamase inhibitory protein, BLIP-II, found in the culture supernatant of Streptomyces exfoliatus SMF19, shows no discernible sequence identity with other ${\beta}$-lactamase inhibitory proteins identified in Streptomyces spp. A null mutant of the gene encoding BLIP-II (bliB::$hyg^r$) showed a bald appearance on solid media. Although BLIP-II was initially isolated from the supernatant of submerged cultures, sites of BLIP-II accumulation were seen in the cell envelope. Mutation of bliB was also associated with changes in the formation of septa and condensation of the chromosomal DNA associated with sporulation. The bliB mutant exhibited infrequent septa, showing dispersed chromosomal DNA throughout the mycelium, whereas the condensed chromosomes of the wild-type were separated by regularly spaced septa giving the appearance of a string of beads. Therefore, on the basis of these results, it is suggested that BLIP-II is a regulator of morphological differentiation in S. exfoliatus SMF19.

• 보건행정학회지
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• 제23권4호
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• pp.343-348
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• 2013

Background: Price control alone may not successfully restrain growth in health expenditures. This study aimed to propose fee adjustment model suitable for Korea reflecting health service volume and to clarify applicability of the model by comparing actual conversion factor with estimated conversion factor from simulation of this model. Methods: Fee adjustment model was developed based on Alberta's fee adjustment formula in Canada and 7 alternatives were assessed according to diversely applied parameters of the model. Results: Estimated conversion factors of the tertiary care hospital and the hospital were lower than actual conversion factors, since the utilization of heath service has been increased. However, there was no big difference between estimated conversion factors and actual conversion factors of the general hospital and the clinic. Eventually this fee adjustment model could estimate proper conversion factor reflecting health service volume. Conclusion: This model may be applicable to the mechanism as determining conversion factor between insurer and provider via negotiation and controling growth in health expenditures.