공구의 처짐을 고려한 복합 자려진동에 대한 연구

박중윤 金烏工科大學校 1990 論文集 Vol.11 No.-

The multiple regenerative chatter vibration due to the deflection of tool occurring in orthogonal cutting is investigated. Tool deflection is a bad chatter condition and causes severe chatter. General chatter generates the constant chatter amplitude, but severe chatter due to small tool deflection has varying chatter amplitude and chatter frequency. It is shown that the severe chatter with large tool deflection, the larger chatter amplitude, but the chatter amplitude and chatter frequency are kept constant.

강산 및 강알칼리 음독에서 냉각 용액을 사용한 희석 요법과 중화 요법의 가능성

이중의,송형곤,김동훈,권운용,곽영호,서길준,윤여규 대한응급의학회 2001 대한응급의학회지 Vol.12 No.3

Background: There is no effective treatment modality for caustic agent ingestion. Dilution and neutralization are prohibited because of the risk of secondary thermal injury. This experiment is designed to evaluate the amount of dilution and neutralization heat and to gauge the applicability of dilution and neutralization therapy using cold solutions to suppress the peak temperature. Methods: This is an in-vitro chemical experiment. HCl, CH3COOH, NaOH, and NH4OH are selected as representatives of strong and weak acids and strong and weak alkali, respectively. 20℃, 11.6M, 5.8M, and 2.9M solutions of each acid and alkali are made and mixed using a magnetic stirrer at a room air temperature of 28℃. The peak temperature, the duration above 40℃, and the heat amount are measured or calculated. Results: When a 11.6M HCl or NaOH solution is diluted with same amount of water, 32 or 18cal. per mL of HCl or NaOH is produced, respectively. HCl produces a significant peak temperature, but NaOH does not. The lower the concentration, the lower the amount of heat production. 11.6M CH3COOH and NH4OH solutions don't produce dilution heat.11.6M and 5.8M solutions of all acids and alkali produce destructive neutralization heat. However, 2.9M solutions produce neutralization heat which might be controllable. When a 11.6M HCl or NaOH solution is neutralized with a -10℃ 2.9 M NaOH or HCl solution, respectively, the peak temperature produced is below 40℃ and seems to add little thermal damage to viable tissue. Conclusion: Dilution and neutralization with a cold solution in cases of strong acid or alkali ingestion is a promising method to avoid thermal injury.

압력용기 구조물 용접부에서 잔류응력이 피로균열진전거동에 미치는 영향

이연신,차용훈,김덕중,성백섭 朝鮮大學校 機械技術硏究所 1999 機械技術硏究 Vol.2 No.2

This paper is to investigated the influence of welding residual stresses on the fatigue crack growth behaviors in the vertical direction to the weld bead. So, Co₂Automatic welding was performed on the ASTM A5l6 grade 60 Steel. For skip and continuous fillet welding, the specimens of fatigue cracks are initiated at toe end and beginning of welded specimen. The fatigue life of continue fillet welding is greater then that of skip fillet welding. The fatigue lief of as welded specimen is longer than that of PWHT specimen because the compression residual stress are greater than the other zone, which are near the welding toe notch of welded specimen. For skip and continuous fillet welding, da/dN-ΔK relations show retardation at HAZ and increase linearly at the stable growth region.

한국경제의 구조조정과 정책대안

鄭然中 대진대학교 2004 大眞論叢 Vol.11 No.-

The conclusion derived from this study is as follows: The Korean economi reform needs the introduction of structural reform incentive system and firm clearness accounting.

H∞ 제어에 의한 유연한 로봇조작기의 강건제어

박중윤,박창용 金烏工科大學校 1995 論文集 Vol.16 No.-

Robust Control of a one link flexible robot manipulator is studied. The objective of this paper shows the H∞ robust control for model uncertainty and sensitivity problems of flexible structures. The system is modeled as rigid mode and the first one vibration mode neglecting the other higher degree of vibration modes. H∞ control design is a powerful method for designing robust feedbackcontrol system to achieve the frequency-dependent singular values of shaping specifications. The first, we consider the robust stability analysis for structural uncertainty because of system modeling to overcome the spillover phenomenon. Next, mixed sensitivity problem of robust control system design of good command response, disturbance rejection and noise suppression are considered by achievement of shaping specifications. We show that the feedback system satisfies some design objectives. Simulation results are presented to demonstrate control performance.

金利政策이 證券市場에 미치는 效果에 관한 硏究

鄭然中 대진대학교 1997 大眞論叢 Vol.5 No.-

A positive analysis has been done on the impact that the interest rate policy will have on both the financial market and the stock market. And the outlook of how the stock market will move when interrest rates have been liberalized has also been discussed. The conclusion drawn from the above analysis is as follows: Changes in interest rates in Korea had certainly an adjusting effect, although to a limited extent, on the flow of financial funds in the past, but it has also been found that those interest rate changes have little impact on the stock market, particularly on the stock price movement. That is, interest rate changes on certificate of deposits and other short term money market funds have an effect on the stock price movements in the short run, but have been found out through regression analysis that those changes have no correlation with them from a long-term perspective. In conclusion, the liveralization of interest rates that is currently under way in Korea should be done gradually, selectively, and under certain guidelines in the short term. And the optimal level of interest rates should be the one that is determined based on international rates of interest and that can perform the function of efficient distribution of financial capital. The liberalization of interest rates would gave effect on the stock market to a considerable extent in the short run due to the synergism of investor confidence and various other related factors, but in the long run, the impact would not likely be significant. This analysis and the conclusion based on it have an inherent limitation, in that they lack multi-regression analysis due to the limited data materials, and this issue will have to be left as a subject of further study.

都市住居空間에서의 中心性 解釋에 관한 硏究

이중우,이윤정 啓明大學校 産業技術硏究所 1999 産業技術硏究所 論文報告集 Vol.22 No.1

This study first investigates the concept and the meaning of centrality from the viewpoint of CHe-Yong-Sang theory as applied to architectural space and secondly investigates the way in which the centrality of modern urban dwelling space is perceived. The findings indicate that the centrality of modern urban dwelling space is perceived in more complex manners than is the case with the traditional dwelling space. While the centrality of dwelling space is observed at different locations, its significance persists in the urban dwelling space.

하드디스크 헤드 위치 결정 기구의 고주파수 대역화에 관한 연구

박중윤,小野京石 金烏工科大學校 1999 論文集 Vol.20 No.-

In order to increase the track density of a magnetic hard disk storage, it is most important to increase the frequency bandwidth of the head positioner. This paper describes the dynamics for a swing arm head positioner of a 3.5″hard disk drive. and investigates the inphase modes design of the two natural modes to increase the frequency bandwidth. The inphase modes have same sign of the residue for each principal vibration mode. This means each mode has same dynamic characteristics in the actual frequency region. Design factors such as bearing characteristics, bended angle and the location of mass center are considered. In isotropic bearing case, when the bended angle is increased, the inphase mode region is also increased. Thus a bended arm mechanism is recommended. But, in anisotropic bearing case, the principal mode direction of the bearing stiffness rather than the bended angle is more effected for increasing the inphase region.

패혈증 백서 모델에서 비타민-C의 효과

이중의,신상도,표창해,서길준,정성은,윤여규 대한응급의학회 1999 대한응급의학회지 Vol.10 No.4

Background : Multi-organ failure from sepsis is very lethal disease entity, which is suspected to be caused by activated inflammatory cells. Inflammatory cells activated by endotoxins generate oxidants and cytokines such as TNF-α and IL-6, which in turn stimulate macrophages and neutrophils. Augmented inflammation makes an organ-injury deteriorate into an organ-failure, which may progress to multi-organ failure. This study is designed to evaluate the therapeutic effects of vitamin-C, a scavenger of oxidants, in sepsis. Methods : Male Sprague-Dawley rats were divided into 3 groups : a control group, a group injected intrapetoneally with LPS(lipopolysaccharide), and a group injected intraperitoneally with LPS and vitamin-C. Each eight rats were sacrified 24 hours and 48 hours after injection, and samples of the blood, the liver and the lung were obtained. Biochemical assays of TNF-α level in the blood and malondialdehyde(MDA)level, catalase activity and nitric oxide synthase(NOS)activity in the liver and the lung tissues were performed. Results : Serum TNF-α level, tissue lipid peroxidation and tissue i-NOS activity were dramatically increased, and tissue catalase activity was exhausted rapidly in sepsis. High dose vitamin-C administration decreased serum TNF-α level, tissue lipid peroxidation and tissue i-NOS induction, and protected against catalase exhaustion. Conclusion : high dose vitamin-C therapy was proved to have definite antioxidant effect in septic condition.

經濟發展과 資本自由化에 관한 硏究

鄭然中 대진대학교 1999 大眞論叢 Vol.7 No.-

The purpose of this study is measuring the effects of capital market liberalization on the economic growth in Korea. The conclusion drawn from the above analysis is that capital market liberalization should be carried out step by step, gradually, by the planned schedules.