Measurement of $^{93}Nb(n,n{\alpha})^{89m}Y$, $^{93}Nb(n,{\alpha})^{90m}Y$ and $^{93}Nb(n,2n)^{92m}Nb$ Cross Sections for 14 MeV Neutrons

김영석,김낙배,정기형,박혜일,Kim, Y.S.,Kim, N.B.,Chung, K.H.,Bak, H.I. Korean Nuclear Society 1986 Nuclear Engineering and Technology Vol.18 No.2

The $^{93}Nb(n,n\alpha)^{89m}Y$, $^{93}Nb(n,{\alpha})^{90m}Y$ and $^{93}Nb(n,2n)^{92m}Nb$ cross sections at a neutron energy of 14.6 MeV have been measured relative to the $^{27}Al(n,p)^{27}Mg$ and $^{27}Al(n,{\alpha})^{24}Na$ cross sections. A small accelerator utilizing $T(D,n)^4He$ reaction was used as a neutron source and the neutron energy spread is about 0.4MeV at the sample. All induced activities were measured with a 70cc HPGe detector in the same geometry.

에탄올을 첨가한 TMA 포접화합물의 냉각특성에 대한 연구

김창오,정용우,박호진,김진흥,정낙규 朝鮮大學校 機械技術硏究所 2002 機械技術硏究 Vol.5 No.1

The purpose of this study is to investigate the propriety of TMA clathrate as a cold storage medium. Particularly, this is to examine the extent of subcooling improvement when the additives are added to the TMA clathrate, because water used cold storage material has low phase change temperature and subcooling. This study has been analyzed and compared with TMA 30 wt% clathrate how phase change temperature, subcooling and specific heat in the various concentrations are changed. This results view to be improved phase change temperature and subcooling of TMA 30wt% as a cold storage medium, when it had some additive. Additionally, it is found that the additive must be controlled under available solution limit and study for new additive must be lasted to know its effect.

포접화합물에 대한 첨가제의 영향에 관한 연구

정낙규,김진홍,김창오,강승현,정종현 조선대학교 에너지.자원신기술연구소 2004 에너지·자원신기술연구소 논문지 Vol.26 No.2

Clathrate compound is suitable for cooling applications as it possesses latent heat in the range of 5-12C, has a cooling storage capacity 2.3 times as large as that of the conventional chilled water. Because clathrate compound is a cooling medium with high thermal density, air-conditioning systems using clathrate compound are expected to substantially reduce cooling medium transportation costs and make an important contribution to energy savings, with attendant benefits in reducing CO_(2) emissions. But, supercooling phenomenon in the phase change process of water cause to increase the cooling capacity and to decrease COP of the refrigerator. Thus, the improvement of supercooling and thermal properties as phase change temperature are expehmentally investigated by comparing TMA30wt% clathrate compound with TMA30wt% clathrate compound that some additives are added.

Experimental investigation of Wheeler's hardening model for Pusan clays

Chung, S.G.,M. Suneel,K.N. Prasad,Rao, K.G. 東亞大學校建設技術硏究所 2004 硏究論文集 Vol.28 No.1

The present paper adopts Wheeler's model (1997) to evaluate its application to Pusan clays. A program of triaxial and consolidation tests on samples of Pusan clays at Yangsan, Korea was under taken to investigate the applicability of the model adopted. The model parameters are evaluated by describing the initial state of the soil. Model predictions are shown to be qualitatively consistent with experimental observations, but refinement seems to be required to have much better agreement between experimental results and model predictions.

TMA 포접화합물의 냉각특성에 미치는 Acetone의 영향

김진홍,정낙류,김창오,강승현,정종현 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.2

An experimental investigation is conducted to measure phase change temperature and supercooling when acetone is added to TMA30wt% clathrate during cooling process in heat source. The results show that phase change temperature is about 4.5~5.5°C when acetone is added to TMA30wt% clathrate during the cooling process in heat source -6, -7℃ and -8℃, supercooling is repressed about 2~8℃ when 0.08wt% acetone is added to it.

The Repressive Activity of Hepatitis C Virus Core Protein on the Transcription of p21 is Regulated by PKA-Mediated Phosphorylation

Chung,E. Y.,Lee,M. N.,Ahn,J. Y.,Jang,K. L. 한국생명과학회 2001 한국생명과학회 학술발표회 Vol.31 No.-

HCV core protein is known to repress the transcription of p21 directly in a p53-independent manner. In this study, the region of HCV core protein responsible for the transcriptional repression of p21 promoter was determined. N-terminal half of core protein almost completely lost the ability to repress p21 promoter, indicating that the domain required for the majority of p21 repression is located between amino acid positions 91 and 191. The trans -repression activity of HCV core mutant S99L on p21 gene expression was similar to that of wild type core protein whereas mutation of the 116th amino aicd Ser into either Ile or Ala complely abolished the repressive ability of HCV core protein. In addition, the trans -repression activity of HCV core mutant S116N was similar to that of wild type core protein, suggesting that an acidic aspartate residue can mimic the effect of phosphorylation. When treated with a PKA inhibitor (HA1004), the inhibitory activity of wild-type HCV core protein was dose-dependently decreased and was completely lost at the concentration of 5μM. On the contrary, the repression activity of HCV core protein was increased by treatment with a PKA activator, indicating, that the p21 repressive activity of HCV core protein is regulated by phosphorylation at 5-116 by PKA. The growth rate of HCV Core-expressing cell line was about 2 fold higher compared to that of the parent cells, suggesting that the repression of p21 transcription by HCV core protein is actually connected to the stimulation of cell growth.

Effect of Dopamine on a Voltage-Gated Potassium Channel in a Jellyfish Motor Neuron

Chung, Jun-mo,Spencer, Andrew N. 이화여자대학교 생명과학연구소 1996 생명과학연구논문집 Vol.7 No.-

To swimming motor neurons(SMNs)of Polyorchis penicillatus, a hydrozoan medusae, dopamine(DA)acts as an inhibitory neurotransmitter by hyperpolarizing its membrane potential and decreasing its firing rate as well. Such an inhibitory action of DA is caused by an increased pemeability to potassium(K)ions. To investigate whether voltage-gated K channels are directly responsible for the membrane hyperpolarization induced by DA, we employed whole-cell voltage clamp configuration. One μM DA applied to SMNs increased the peak and rear values of voltage-gated K currents by 37 and 54%, respectively, in a reversible manner. Combined with subtraction analysis, this result suggests that the outflux of K ions by DA in SMNs occurs mainly through rectifier-like K channels.

Action of Dopamine as Inhibitory Neuromodulator in Jellyfish Synapse

Chung, Jun-Mo,Spencer, Andrew N. The Korea Science and Technology Center 1998 BMB Reports Vol.31 No.3

Dopamine (DA) acts on swimming motor neurons (SMNs) of Polyorchis penicillatus as an inhibitory neurotransmitter by hyperpolarizing their membrane potentials, which results from the activation of voltage-sensitive potassium channels mediated through a D₂-type receptor. In addition, DA, and not the hyperpolarized membrane potential, directly decreased the input resistance of SMNs by ca. 50% from 1.42 to 0.68 GΩ. It strongly indicates that DA can shunt other excitatory synaptic signals onto SMNs where DA usually elicited much greater responses in their neurites than soma. All these evidences suggest that DA may operate in this primitive nervous system in dual modes as an inhibitory neurotransmitter and neuromodulator as well.

테니스 競技 技術 向上을 爲한 硏究

鄭秦宇,朴昌植,李錫南,丁小鳳 경희대학교 체육과학연구소 1978 體育學論文集 Vol.6 No.-

The following results were achieved by means of checking the playing arts, the won points and the rate of Service, Ground Stroke, Volley, Smashing in the game of Joo Nam Champion VS Im Ho Champion in Semi Final Match of Male Single, the game of Joo Nam VS Kim 11 for final match, between Saideill of Pakistan VS Kim 11 of Korea for the first single match of elimination contest in East area for Davis Cup, the game between Joo Nam, Korean champion VS Muhamed of Pakis tan for second single match, for purpose of investigating the game quality of Tennis Champions. 1. 106 points in 645 services for the first service and its succession rate of 16.43% and 34 points in 307-serfice for second service and its succession rate was 11.07% in the services. 2. 181 points in 2069-stroke for foreground storke and its succession rate was 8.74%, 193 points in 2437-stroke for backhand ground stroke and its succession rate was 7.92%. 3. 219 points in 629-volley in the volley play and its succession rate was 34.82%. 4. In smashing plays, 52 points in 108-smashing and its succession rate was 48.15%. As shown in the above, smashing, volley, first service have showe a high succession rate in terms of point for all champions, and second service, forehand ground stroke, backhand ground stroke have shown lower rate. Accordingly it has been learned that, in Tennis Games, Volley and Smashing closing to Net with strong service make a good point rather than a inactive play being hoped for point by ground stroke close to the base line upon waiting for a miss of counter player.

Geotechnical Characteristics of Marine Clay in Busan New Port

Chung, S.G.,Ryu, C.K.,Beak, S.H.,Huh, D.Y.,Jo, K.Y.,Lee, N.K.,Ninjgarav 東亞大學校建設技術硏究所 2004 硏究論文集 Vol.28 No.1

Since early 1990s reclamation projects in Busan and its vicinity in Nakdong River plain have been performed for industrial and residential complexes. As well it has started to build a new port (Busan Newport) due to increase in overloads of Busan port since late 1990s. In the area the sedimentary deposit is composed of soft clay of about 30m thick, thin sand layer of 3-4m thick, hard clayey soil, and then basal conglomerates and sandy sediments, total thickness of which is about 70m at the maximum under seawater. For the huge project many contract companies have simultaneously performed geotechnical investigations to get design parameters. Based on the harmful experiences gained by the previous projects, it was also required to pay careful attention to sampling and laboratory and field tests for the project. Nevertheless the results of laboratory tests were so scattered and then resulted in difficulty to evaluate the design parameters. Existing data has been reviewed to evaluate the validity or cause of their variation. In addition geological study, sampling and soil tests have been carefully carried out at a few locations. Using the results the clay would be effectively characterized for depositional environment and its relation to soil properties.