• Bulletin of the Korean Chemical Society
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• 제25권8호
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• pp.1241-1243
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• 2004

• 천문학회지
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• 제30권1호
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• pp.95-106
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• 1997

We investigate the velocity distribution of dark matter in the disk of a galaxy like the Milky Way at the solar radius. Using N-body simulations with the total mass and z-component of angular momentum conserved, we calculate the response of a dissipationless dark matter galactic halo during the dissipational collapse of the baryonic matter in spiral galaxy formation. The initial distribution of dark matter and baryonic particles is assumed to be a homogeneous mixture based on a King model. The baryonic matter is assumed to contract, forming the final luminous components of the galaxy, namely the disk and, in some cases, a bulge and central point. Both slow and fast growth of the luminous components are considered. We find that the velocity distribution of dark matter particles in a reference frame rotating slowly about the galaxy center in the plane of the disk is similar to a Maxwellian, but it is somewhat boxier, being flatter at the peak and truncated in the tails of the distribution. We tabulate parameters for the best-fitting Maxwellian and modified-Maxwellian distributions. There is no significant difference between slow collapse and fast collapse for all these results. We were unable to detect any effect of disk formation on the z-dependence of the dark matter density distribution.

• Fisheries and Aquatic Sciences
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• 제6권4호
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• pp.194-202
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• 2003

Budgets for water, nitrogen, and chemical oxygen demand (COD) were determined in two 0.012 ha earthy-bottom ponds stocked with Israeli strain common carp at an initial stocking density of $20\;fish/m^3$. Total ammonia nitrogen (TAN) concentrations increased continuously but later decreased in pond A as a consequence of high nitrification. COD concentrations increased during the experimental period due to the accumulation of feed input. Nutrient budgets showed that feed represented $94-95\%$ of nitrogen input and about 99% of organic matter input. Fish harvest accounted for $40\%$ of nitrogen and organic matter input. Seepage and water exchange removed $15-17\%$ of nitrogen input but only $1-2\%$ of organic matter. Draining of the ponds removed $20-26\%$ of input nitrogen, mostly in inorganic forms, but removed only minus organic matter. Fish and water column respiration accounted for $39\%$ of organic matter input, and benthic respiration accounted for $7-12\%$ of organic matter input. No significant change of nitrogen and organic matter in both pond bottoms were found during the three-month growth period. The unrecovered input nitrogen, about $6.3-13\%$, was lost through denitrification and ammonia volatilization. On a dry matter basis, fish growth removed $31\%$ of total feed input and left $69\%$ as metabolic wastes.

• 한국산업융합학회 논문집
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• 제10권1호
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• pp.15-20
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• 2007

The aim of this study is to measure the removal characteristics of organic matter and bacteria with the use of ozone to reduce the problems caused by bacteria and organic matter which appear in sea-water is summer season. When the total input of ozone was $1.4mg/{\ell}O_3$, the removal rate of bacteria and E-coli from sea-water proved to be 100%. With the same input of ozone, on the other hand, the removal rate of COD turned to be relatively low, 50%, which was to the fact that sea-water consists of salt matter which is a kind of COD matter. This result supports the idea that we can keep using ozone steadily in the future to remove organic matters and bacteria from sea-water because ozone destructs relatively less salt matter in sea-water. Also, the treatment effect rate of SS, turbidity and organic matters such as $NH_3$-N, $NO_3$-N etc, was very high. As a result, we assume that the treatment of organic matter in sea-water with ozone is very effective

• Journal of Korean Biological Nursing Science
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• 제20권1호
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• pp.20-29
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• 2018

Purpose: This study aimed to determine the relationships between particulate matter risk perception, knowledge, and perceived barriers and health-promoting behaviors among college students. Methods: Data for this cross-sectional study were collected from September 1 to 30, 2017. The study sample consisted of 85 students from a university, Seoul. Students not living in the Seoul metropolitan area during the spring 2017 semester were excluded from participation. Pearson's correlation coefficient was used to identify relationships among study variables. Results: A significant positive correlation existed between particulate matter risk perception and health-promoting behaviors related to particulate matter (r= .51, p< .001). Among the risk perception subdomains, attention (r= .47, p< .001) and health effect (r= .55, p< .001) showed strong positive relationships with health-promoting behaviors. No significant relationships were found between knowledge (r= .12, p= .288) or perceived barriers (r= -.12, p= .264) and health-promoting behaviors related to particulate matter. Conclusion: Based on the study results, strategies for enhancing particulate matter risk perception are needed to increase the level of health-promoting behaviors related to particulate matter among college students.

• Asian-Australasian Journal of Animal Sciences
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• 제4권3호
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• pp.235-240
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• 1991

A CRD experiment with thirty growing cross bred calves were assigned at random to three treatments rations. 1) $T_0$, 0% Urea + 20% M. O. cake, 2) $T_1$, 1% Urea + 10% M. O. cake and 3) $T_2$, 2% Urea + 0% M. O. cake to develop a rice straw based ration for ruminants. Sweetish odour and yellowish colour were observed in good recovered silage. Organic matter varied from 87.45% to 89.63% whereas crude protein varied from 14.0% to 14.5% in each treatment. No significant differences were found among the nutrient composition of the ration. The dry matter in take (DMI) and dry matter digestibility was higher in $T_0$ (0% Urea) than those of ration containing 1% ($T_1$) and 2% Urea ($T_2$). The organic matter digestibility decreases with increasing doses of urea. The crude protein & nitrogen-free-extract digestibility were found higher in the ration $T_1$ containing 1% urea whereas crude fibre digestibility and available metabolizable energy (ME) were higher in $T_0$ containing no urea as compared to $T_1$ and $T_2$. Total digestible nutrient (TDN) decreases with the increase of urea level. The highest feed efficiency was found in $T_0$ having no urea and lowest was in $T_2$. The animals gained in weights from each ration. Highest gain in weight was found in $T_0$ ration, then followed $T_1$, and $T_2$. This is due to natural protein available in M. O. cake only. It is concluded that supplemetation of urea or M. O. cake with readily available energy source as molasses upto 20% of total dietary dry matter in a complete ration may increase the intake of low quality fibrous roughage only when nitrogen and mineral are not limiting factor.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.76-82
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• 2015

Active matter는 스스로 에너지를 가지고 움직이는 개체들이 서로 상호작용을 하여 집단적인 움직임을 보이는 물질이다. Rotational noise model은 반발 상호작용과 rotational noise를 가지고 있는 self-propelled particle로 active matter를 설명한다. 이 연구에서는 rotational noise model에서의 상 도표와 클러스터 형성을 알아보고 입자들의 집단적인 운동을 도와주거나 방해할 수 있는 leader 입자와 seed가 클러스터의 운동에 어떠한 영향을 주는지 알아본다.

• 천문학회보
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• 제45권1호
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• pp.47.3-48
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• 2020

I will present the Sejong Suite, an extensive collection of state-of-the-art high-resolution cosmological hydrodynamical simulations spanning a variety of cosmological and astrophysical parameters, primarily developed for modeling the Lyman-Alpha forest. Adopting a particle-based implementation, we follow the evolution of gas, dark matter (cold and warm), massive neutrinos, and dark radiation, and consider several combinations of box sizes and number of particles. Noticeably, for the first time, we simulate extended mixed scenarios describing the combined effects of warm dark matter, neutrinos, and dark radiation, modeled consistently by taking into account the neutrino mass splitting. Along the way, I will also highlight some new results focused on the matter and flux statistics.

• 한국초지조사료학회지
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• 제17권2호
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• pp.110-116
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• 1997

The objective of this experiment was to suggest the optimum nitrogen fertilization level for orchardgrass(0G)- red clover(RC) mixtures. The field trials were conducted from 1993 to 1994 in order to evaluate the dry matter yield, botanical composition, chemical composition, dry matter digestibility(DMD), crude protein dry matter (CPDM) and digestible dry matter(DDM) yields on the nitrogen levels( 0, 50, 100, 150 and 300kgha). The results obtained were summarized as follows : 1. With increasing nitrogen levels, the DM yield of OG-RC mixttures significantly increased(P<0.05). The maximum total DM yield (7,964kgha) was obtained at N 300kgha level, However, there was no significant difference between N 150 and 300kgha. 2. With increasing the nitrogen levels, the botanical composition of OG in OG-RC mixttures was significantly increased(P< 0.05), whereas that of RC was remarkably decreased(P< 0.05). 3. The CP content was decreased by increasing nitrogen level(P

• Asian-Australasian Journal of Animal Sciences
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• 제29권7호
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• pp.965-970
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• 2016

This study was conducted to determine the effects of freezing and supplementation of molasses (M), lactic acid bacteria (LAB) and LAB+enzyme mixture on chemical and nutritional composition of sunflower silage (SF). Sunflower crops were harvested (at about $29.2%{\pm}1.2%$ dry matter) and half of fresh sunflower was ensiled alone and half was frozen (F) at $-20^{\circ}C$ for 7 days. Silage additives were admixed into frozen SF material. All samples were ensiled in glass jars with six replicates for 90 days. The treatments were as follows: i) positive control (non-frozen and no additives, NF), ii) negative control (frozen, no additives, F), iii) F+5% molasses (FM), iv) F+LAB (1.5 g/tons, Lactobacillus plantarum and Enterococcus faecium, FLAB); v) F+LAB+enzyme (2 g/tons Lactobacillus plantarum and Enterococcus faecium and cellulase and amylase enzymes, FLEN). Freezing silage increased dry matter, crude ash, neutral detergent fiber, and acid detergent lignin. The organic matter, total digestible nutrient, non-fiber carbohydrate, metabolizable energy and in vitro dry matter digestibility were negatively influenced by freezing treatments (p<0.05). In conclusion, freezing sunflower plants prior to ensiling may negatively affect silage quality, while molasses supplementation improved some quality traits of frozen silage. Lactic acid bacteria and LAB+enzyme inoculations did not effectively compensate the negative impacts of freezing on sunflower silage.