• 한국소음진동공학회논문집
• /
• 제17권11호
• /
• pp.1119-1126
• /
• 2007

In this paper, the dynamic stability of a cracked cantilever pipe conveying fluid with tip mass is investigated. The pipe is modelled by the Euler-Bernoulli beam theory in which rotatory inertia and shear deformation effects are ignored. The equation of motion is derived by the energy expressions using extended Hamilton's Principle. The crack section is represented by a local flexibility matrix connecting two undamaged pipe segments. The influence of the crack severity, the position of crack, the mass ratio, and a tip mass on the stability of a cantilever pipe conveying fluid are studied by the numerical method. Besides, the critical flow velocity and the stability maps of the pipe system as a function of mass ratios($\beta$) for the changing each parameter are obtained.

• Journal of Mechanical Science and Technology
• /
• 제14권12호
• /
• pp.1396-1402
• /
• 2000

Here is investigated the characteristics of double-diffusive convection in thermally-stable stratified horizontal fluid layer. By employing an electrochemical technique, and adopting aqueous CuSO$_4$-H$_2$SO$_4$solution as electrolyte, experiments on ionic mass transfer have been conducted systematically. And, also a new mass transfer correlation in double-diffusive situations has been derived by extending the model of micro-scales of turbulence, which was proposed by Arpaci. The resulting correlation of the Sherwood number as a function of the thermal Rayleigh number was in good agreement with the present experimental results. The present study provides plausible understanding in controlling both mass and heat transfer rates for practical situations including double-diffusive convection.

• 한국멀티미디어학회:학술대회논문집
• /
• 한국멀티미디어학회 2000년도 추계학술발표논문집
• /
• pp.571-574
• /
• 2000

오늘날 단백질 정보 분석은 HGP(Human Genome Project)이후 Post-genome 시대를 맞이하면서 매우 중요한 분야로 인식되고 있다. 이 단백질 정보를 이용하는 응용은 Discovery of Protein Structure/Function Relationships, Evolutionary Relationships, 3D Modeling 등 많은 분야에서 활용되어진다. 여러 가지 분야들 중에서 특히 단백질 구조 분석을 위한 많은 다양한 소프트웨어들이 출현되고 있다. 하지만 복잡하게 얽혀 있는 단백질들을 검증하기 위해서 Mass Spectrometry에서 발생되는 Peptide Masses의 정보들을 이용할 수 있다. 이에 본 논문에서는 Mass Spectrometry에서 생성된 Peptide Mass Map을 이용하여 기존의 단백질 Database에 있는 단백질들과 비교하는 자동화 단백질 검증 시스템 설계 및 구현에 관한 연구내용을 담고 있다. 이 시스템은 3-계층 중심으로 개발이 이루어지며 이 기종 시스템과의 원활한 통신 다중 계층의 환경에 있는 각 객체들간에 통신을 위해서 RMI 기반의 미들 웨어를 활용하기로 한다.

• Journal of Korean Neurosurgical Society
• /
• 제37권1호
• /
• pp.63-66
• /
• 2005

The authors report a case of Currarino triad which had a congenital anorectal stenosis associated with a sacral defect and a presacral mass. A 1-year-old female presented with constipation since birth. Neurological deficits were not found on admission. She had had a diverting colostomy due to anorectal stenosis at another hospital before admission. Lumbar X-ray films showed bony defect caudal to the third sacral vertebra. Magnetic resonance image demonstrated a round cystic pelvic mass which was connected with a dural sac via anterior sacral defect. Posterior approach with Intradural removal of the presacral cystic mass was performed and followed by anoplasty by a pediatric surgeon. The cystic mass was verified histologically as mature teratoma with cystic change. Postoperatively, the urinary function and bowel movement remained intact. Currarino triad should be suspected and evaluated physically and radiographically in a case of congenital anorectal stenosis. Prompt recognition and close cooperation between pediatric surgeons and neurosurgeons is advisable to ensure adequate surgical treatment.

• 한국자동차공학회논문집
• /
• 제10권2호
• /
• pp.193-200
• /
• 2002

Simple spring-damper-mass models have been widely used to investigate whole-body vortical biodynamic response characteristics of the seated vehicle driver. Most previous models have not considered the effect of wobbling masses; i.e. heart, lungs, liver, intestine, etc. In this study, 4 -DOF seated driver model including one non-rigid mass representing wobbling visceral mass, 5-DOF model including intestine, and 10-DOF model including five lumbar vertebral masses were proposed. The model parameters were identified by a combinatorial optimization technique. simulated annealing method. The objective function was chosen as the sum of error between model response of seat-to-head transmissibility and driving point mechanical impedance and those of experimental data for subjects seated erect without backrest support. The model response showed a good agreement with the experimental response characteristics. Using a 10-DOF model, calculated resonance frequency of lumbar spine at 4Hz was matched well with experimental results of Panjabi et al.

• Nuclear Engineering and Technology
• /
• 제49권1호
• /
• pp.234-244
• /
• 2017

Natural frequencies of immersed square sections decrease due to a contribution of added mass to the movement of square sections. In this study, natural frequencies of square sections are obtained as a function of gap size between the square section and a rigid square wall using the finite element method. Additionally, they are used to extract the added mass effect on translational and rotation motions. Published information and studies on the translational and torsional vibration of square beams are also examined for practical use. D coupling of a square section is also investigated for multiple square sections. The suggested added mass estimation can be applicable to the spent fuel storage design of a pressurized light water modulated nuclear power plant.

• Structural Engineering and Mechanics
• /
• 제3권1호
• /
• pp.61-74
• /
• 1995

A linearly tapered, doubly symmetric thin-walled closed member, such as power-transmission towers and tourist towers, are often characterized by local variation in mass and/or rigidity, due to additional mass and rigidity. On the preliminary stage of design the closed-form solution is more effective than the finite element method. In order to propose approximate solutions, the discontinuous and local variation in mass and/or rigidity is treated continuously by means of a usable function proposed by Takabatake(1988, 1991, 1993). Thus, a simplified analytical method and approximate solutions for the free and forced transverse vibrations in linear elasticity are demonstrated in general by means of the Galerkin method. The solutions proposed here are examined from the results obtained using the Galerkin method and Wilson-${\theta}$ method and from the results obtained using NASTRAN.

• 생태와환경
• /
• 제41권3호
• /
• pp.320-330
• /
• 2008

소하천에 서식하는 수서곤충 29 분류군에 대한 몸길이와 건조질량, 그리고 회분외질량에 관한 회귀식이 자연 log로 변환된 멱함수를 이용하여 구해졌다. 수서곤충은 강원도 북부지방의 산간계류에서 채집되었다. 각 분류군에서 주어진 몸길이에 대해 회귀식이 예측하는 건조질량은 기 보고된 다른 저자들의 예측값과 대체로 유사하였지만, 체벽이 연하고 이동할 때 몸을 수축-이완하는 분류군에서는 다른 저자들이 예측값에 비해 높았다. 수서곤충의 평균 회분율은 건조질량의 10%였으며, 섭식기능군간 차이는 인정되지 않았다.

• 천문학회보
• /
• 제35권1호
• /
• pp.52.1-52.1
• /
• 2010

The relationship between orbital periods of cataclysmic variables (CV) and mass-loss rates of their donor stars is an important subject of theoretical researches. The observed donor's radii are oversized in comparison with those of isolated unperturbed stars of the same mass, which is thought to be a consequence of the mass-loss. Using the empirical mass-radius relation of CVs and the Hayashi theory for changes in effective temperature, orbital period, and luminosity of the donor with the stellar radius, we find the mass-loss rate of CVs as a function of the orbital period P. The derived mass-loss rate is more or less constant at 10-9.6-10-10M$\odot$ yr-1 with P above 90 minutes and declines very rapidly with P below 90 minutes, reaching 10-10.3-10-11.7M$\odot$ yr-1 when P is close to the minimum period. The turnaround behavior of the mass-loss rate shape with P near the minimal period is much less pronounced than suggested by earlier numerical models, making observational detection of the turnaround highly unlikely. When applied to our new results, SDSS 1035, 1507, 1501 and 1433 systems, previously known as post-bounce CVs, are more likely to be systems that have yet to reach the minimal period.

• 한국광학회지
• /
• 제9권6호
• /
• pp.396-402
• /
• 1998

광학계의 결상성능평가는 optical transfer function(OTF)을 측정하는 것이 표준적인 방법으로 사용되고 있다. 그러나, 대량 생산되는 광학계의 경우에서는 측정의 편리함 때문에 test pattern을 투영하여 contrast를 검사하는 방법도 많이 사용되고 있다. 본 연구에서는 회절결상이론을 사용하여 주기적 line-space pattern에 대한 contrast transfer function(CTF)을 계산하는 프로그램을 개발하고, C­계수와 Zernike 다항식으로 표현되는 3차 파면수차에 의한 광학계의 modulation transfer function (MTF)과 CTF 변화를 비교, 분석하였다.