調和 集中 荷重을 받고 回轉하는 타이어에서 音響 放射

김병삼,홍동표 全北大學校 1992 論文集 Vol.34 No.-

The Problem of sound radiation from rotational tire under the action of harmonic point forces is studied. The reaction on the vibratory response of the rotational tire is taken into account. The rotational tire is assumed to occupy the plane y = 0. The rotational tire material and the elastic foundation are assumed to be lossless and Bernoulli-Euler beam theory including a tension force (T), damping coefficient (C) and stiffness of foundation (k_s) will be employed. The non- dimensional sound power is derived through integration of the surface intensity distribution over the entire rotational tire. The expression for sound power is integrated numerically and the results examined as a function of wavenumber ratio (γ) and stiffness factor (ψ). Here, our purpose is to explain the response of sound power over a number of non-dimensional parameters describing tension, stiffness, damping and foundation stiffness.

저장 온도 및 상대습도가 비타민 정제 중 지용성 비타민 함량의 변화에 미치는 영향

김동섭,이재황,김세곤,이동언,박석준,이진희,이강표,최성원,백무열 경희대학교식량자원개발연구소 2007 硏究論文集 Vol.26 No.1

정보통신산업의 국민경제적 위상과 전망

김용규,문석웅,홍동표 한양대학교 디지털경제연구소 2003 디지털경제연구 Vol.8 No.-

승용차용 알루미늄 합금 휠의 진동특성에 관한 실험적 연구

金秉三,홍동표 全北大學校 1993 論文集 Vol.36 No.-

Vibration characteristics of a wheel play an important role to judge a ride comfortability and quality for a passenger car. In this study, the vibration characteristics of al-alloy and steel wheel for passenger car are studied. Natural frequency, damping and mode shape are determined experimentally by frequency response function. Results show that wheel material property, size and design are parameter for shift of natural frequency and damping.

X선 프렉토그래피기법을 이용한 금속복합재료의 피로손상 해석에 관한 연구

김광영,박동성,박영철,윤두표,김득진 韓國非破壞檢査學會 1998 한국비파괴검사학회지 Vol.18 No.3

본 연구에서는 비파괴방법중 대단히 효과적인 방법이라 할 수 있는 X선 프렉토그래피 방법을 이용하여 파괴역학적 파라메타인 ΔK, Kmax의 정량적인 평가의 가능성에 대하여 검토하였다. 이를 위하여 Al2009-15v/o SiCw 복합재료와 SS41 불림재를 이용하여 피로균열진전시험을 실시하고 그 결과로부터 파면상의 X선 프렉토그래피 파라메타와 파면형성시의 파괴역학적 파라메타를 비교 ㆍ검토하여 X선 프렉토그래피에 의한 ΔKdhk Kmax의 평가 방법에 대하여 연구하였다. 또한, 정적하중부에 의한 소성변형률의 비파괴적 평가법에 대하여도 검토하였다. 이를 위하여 인장시험으로 소성변형을 부하한 후, X선 프렉토그래피 파라메타를 이용하여 부하된 소성변형량의 비파괴평가법에 대하여 검토하였다. 그 결과 피로파괴시의 부하된 Kmax와 피로손상 정도를 X선 프렉토그래피에 의하여 정량적으로 평가할 수 있는 방법을 제시하였다. It is attempted to verify the Quantitative relationship between fracture mechanical parameters(ΔK, Kmax)and X-ray parameters (residual stress, half-value breadth) of Al2009-15v/o SiCw composite, and normalized SS41 steel. In this study, fatigue crack propagation test were carried out X-ray diffraction was applied to fatigue fractured surface in order to investigate the change of residual stress and half-value breadth on fatigue fractured surface. And it is loaded prestrain to each tensile specimen, Al2009-15v/o SiCw composite(0.3,0.5,1,1.5,2%) and normalized SS41 steel(0.63,7.50,13.7,20%),for investigating plastic strain rate using nondestructive measurement method. X-ray diffraction was applied to the prestrained tensile specimens in order to measure the change of residual stress and half-value breadth.

L-Phenylalanine 생산

김준표,임동준 嶺南大學校 環境問題硏究所 1991 環境硏究 Vol.11 No.1

본 논문은 미생물에 의한 L-phenylalanine생성에 관한 연구로서 E. coli CGSC 4510을 이용하여 NTG(N-methy-N'-nitro-N-nitroso-guanidine)와 penicillin으로 처리하여 L-tyrosine 영양요구성 변이주를 분리하였고 L-phenylalanine의 생산량을 더욱 증가시킬 목적으로 L-tyrosine 영양요구성 변이주를 NTG로 재처리하여 PFP(p-fluoro-phenylalanine) 내성 변이주를 분리하였다. 이 균주를 사용하여 L-phenylalanine을 생성할 때 최적 배지 조성은 탄소원으로 glucose의 초기 농도가 20g/l, 질소원으로 NH₄Cl의 농도가 4g/l 즉, C/N ratio가 5일 때였으며 pH 7.5에서 최대의 L-phenylalanine의 생성을 보였다. 유가식 배양에서 세포 성장의 exponential phase 초기에 n-hexadecane을 1%(v/v)되게 첨가하였더니 세포 성장과 L-phenylalanine 생산량이 우수하였는데 n-hexadecane을 첨가하지 않았을 때 보다 세포성장수율 ?? 은 약 2.2배 증가하였으며 L-phenylalanine 생산수율 ?? 은 48% 증가하였다. The production of L-phenylalanine by Escherichia coli CGSC 4510 was investigated. Mutation techniques were used in order to select the strains which yields the highest L-phenylalanine production. Mutans were induced by N-methyl-N'-nitro-N-nitrosoguanidine(NTG) treatment and then L-tyrosine mutants were induced by NTG and penicillin treatment. PFP(p-fluoro-phenylalanine) resistant mutant was isolated from L-tyrosine auxotrophic mutants with plasmid pSY110-14 and the recombinant cells were used for L-phenylalanine production. The optimum media composition for L-phenylalanine production were 20g/l of glucose, 4g/l of NH₄Cl(C/N=5), When 1%(v/v) n-hexadecane was added at initial exponential phase, the product yield of L-phenylalanine was insreased 49%.

폐염균의 항생제 감수성 검색

김수남,이동권,표석능 성균관대학교 약학연구소 1993 成均藥硏論文集 Vol.5 No.1

Streptococcus pneumoniae remains a major cause of bacteremia, meningitis, penumonia, sinusitis, and otitis media. Although this organism was originally exquisitely susceptible to penicillin, the last two decades have witnessed the emergence of strains resistant to penicillin as well as other antimicrobial agents in many parts of the world. 102 isolates obtained from patients with invasive pneumococcal disease have been examined the susceptibility to various antibiotics. 52% to 85% of isolates tested were resistant to various antibiotics. These data suggest that more powerful antibiotics should be used for the treatment of pneumococal infection.

증점제를 사용한 고유동콘크리트의 기포조직과 내동해성에 관한 실험적 연구

김무한,권영진,강석표,여동구,김용로,장종호 충남대학교 산업기술연구소 2000 산업기술연구논문집 Vol.15 No.1

Recently, lots of studies for high flowing concrete have been suggested under practical use that it is only a way to solve the confronted problem. However, most studies have been concentrated on the manufacture method and properties of fresh concrete, but there is few studies for the durability of hardened concrete, specially for the freezing and thawing. It is generally known that the frost resistance of concrete is much affected by the air content in concrete and by the air void system. The frost resistance is also believed to vary with the strength of concrete. The purpose of this experimental study is to make a comparison between high flowing concrete using viscosity agent and ordinary concrete about the effect of the viscosity agent, air content and curing method on the frost resistance. As the result of tutus study, the frost resistance have not effect the viscosity agent but effect the different of curing methods.

지점부 다이아프램의 응력분배 거동

김동표,정경섭,김경남,양경환 충북대학교 건설기술연구소 2002 建設技術論文集 Vol.21 No.1

These days, bridges have a tendency to be long-spanned and simple ‘ thus, the importance of economy and efficiency has increased for bridge construction. As a result, one of the main members on which interest is focused is the diaphragms. In this study, stress variation of the support diaphragms in a steel box girder was considered. This paper deals with the behavior of the stress distribution on the diaphragms on the bearings of a closed section steel box girder bridge due to the continuous casting of concrete slab. Both experimental and structural analyses were performed to verify the behavior of the stress distribution a composite steel box girder bridge under construction. Strain was continuously checked at intervals of 10 to 30 min. from the beginning of the placement by the Time Interval Function of the measuring instrument. The variation of strain on the diaphragms on the bearings are presented herein.

고밀도 플라즈마에 의해 식각된 SrBi_2Ta_2O_9 박막의 표면 반응 연구

김동표,김창일,장의구 중앙대학교 기술과학연구소 2000 기술과학연구소 논문집 Vol.30 No.-

본 연구에서 SBT 박막은 Cl_2양을 변화하면서 Cl_2/Ar 가스 플라즈마를 이용하여 식각하였다. 최대 식각 속도는 Cl_2(20%)/Ar(80%) 가스혼합비에서 883A˚/min 이었다. Cl_2 가스양이 증가함에 따라서 SBT 박막의 식각 속도는 감소하였다. 이는 Ar 이온의 물리적 스퍼터링에 의한 영향이 화확 반응에 의한 식각보다 우세하게 작용함을 의미한다. 식각 메커니즘을 규명하기 위하여 optical emission spectroscopy (OES), x-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS)와 atomic force microscopy (AFM) 분석을 하였다. AFM 분석결과에서 Ar이나 Cl12 플라즈마를 이용하여 식각된 시료의 표면 거칠기 rms 값이 식각전의 시료나 Cl_2/Ar 플라즈마로 식각된 시료보다 크다. 이는 식각된 시료에서의 Bi 양의 감소나 비휘발성 식각 잔류물에 의한 영향이다. XPS와 SIMS 분석을 통하여 검증하였다. SBT thin films were etched at different content of Cl_2 in Cl_2/Ar. The maximum etch rate of SBT was 883A˚/min in Cl_2(20%)/Ar(80%). As Cl_2 gas increased in Cl_2/Ar gas plasma, the etch rate decreased. The result indicates that physical sputtering of Ar ion is dominant to chemical reaction in etching SBT thin films. To evaluate the etching mechanism of SBT thin films, optical emission spectroscopy (OES), x-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and atomic force microscopy (AFM) were carried out. From the result of AFM, the rms values of etched samples in Ar only or Cl_2 only plasma were higher than that of as-deposited, Cl_2/Ar. This can be illustrated by a decrease of Bi content or nonvolatile etching products(Sr-Cl and Ta-Cl), which are revealed by XPS and SIMS.