• 한국응용과학기술학회지
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• 제19권1호
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• pp.19-24
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• 2002

It is a great role that the character of man or woman could be distinguished by hair on the aspect of ornament. Hair will be support of beautifulness of human being in various permanent wave by many kinds of its drugs. Hair is based upon the skin which enroll the body of high living animals and have multiple membrane structure. This study used rat and the effects of commercial permanent wave products to skin which are composed with thioglycolic acid and bases. Results are as follows. Permanent wave penetrated to 4 hours later with steady state in skins and was not significant changeable after 20hr later. In case of neutralizer with thioglycolic acid lag time and permeability coefficient in healthy skin is 3.38hr and $0.094^{\mu}g/cm^{2}$ ${\cdot}$ hr, it old skin is 3.48hr and 0.129$^{\mu}g/cm^{2}$ ${\cdot}$ hr, and it wounded skin is 4.72hr and $0.158^{\mu}g/cm^{2}$ ${\cdot}$ hr. In conclusion, lag time and permeability coefficient in old skin and wounded skin are faster than healthy skin. In vivo which was studied by general time and method of permanent wave. We notified that fine rinkle and rash of skin were changeable in the case of treating with permanent wave drugs than normal skin. We can see even rash and eruption by the naked eye.

• Annals of Clinical Neurophysiology
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• 제4권2호
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• pp.119-124
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• 2002

Background : Guillain-$Barr{\acute{e}}$ syndrome(GBS) is a neurologically emergent condition, leading to respiratory insufficiency without an early and appropriate treatment. Thus, the treatment of GBS requires early diagnosis but it is difficult due to the low sensitivity of laboratory tools in the initial stage. Hoffman reflex (H-reflex) and its facilitation by Jendrassik maneuver (JM) are sensitive tools evaluating the central circuit of motor system on the spinal cord level. The aim of this study is to test whether the change of H-reflex and F-wave under the JM is able to detect the early stage of GBS and whether GBS involves the central nervous system (CNS). Material and Methods : All 7 GBS patients who showed normal or nearly normal nerve conduction study were included. The facilitation of H-reflex and changes of F-wave were calculated by measuring the percent difference of H-reflex or F-wave amplitude under JM compared to basal H-reflex of F-wave amplitude. The changes of F-wave and H-reflex in the GBS patients were compared with them of 8 healthy controls. Results : The F-wave amplitudes of both healthy controls and GBS patients did not changed under the influence of JM ($102.4{\pm}24.9%$, $108.7{\pm}29.0%$ respectively). However, the facilitation of H-wave by JM in the GBS patients was absent ($98.8{\pm}5.8%$), even though the H-reflex amplitude I the healthy controls increased under the influence of JM ($124.8{\pm}12.1%$). Conclusions : The loss of H-reflex facilitation in GBS implies that this phenomenon might be the most early change detected in the electrophysiological study and support the early diagnosis, and that GBS might include lesion in the spinal motor CNS.

• 한국패션뷰티학회지
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• 제4권3호
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• pp.18-24
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• 2006

Hair is the part of body which expresses man into more manlike. When we create some artworks, we need the most suitable material for the artworks. Similarity, the healthy scalp hair condition and treatment are required to keep our hair clean and healthy. And the improper condition of scalp hair prohibits our hair from normal growing, proceeds the alopecia(loss of hair) and double our physical and mental stresses. The necessity of health treatment of scalp hair which was damaged by frequent permanent hair wave and hair coloring is on the rise. This study will present how to control and treat the scalp hair and will check how we feel about the necessity of scalp hair treatment. This study finally shows that people think their scalp hair conditions are not normal and chemically treated hair in spite of their natural hair. However, most people think that the scalp hair treatment is very useful to their hair and this result enables us to predict the future market of the scalp hair treatment business will be growing day by day. We need to study further not only scalp hair treatment but also prevention stage in order to keep the healthy hair and will check how we feel about the necessity of scalp hair treatment.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.220-223
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• 2008

A test facility to measure the performance of a KM(Kick Motor) is constructed, and prediction of blast wave propagation over the facility is performed to check if the safety of test personnel in MCC(Main Control Center) can be guaranteed even for the most severe explosion. Assuming that the initial explosion energy is contained in a sphere under the pressure of 500, 1000, 1500 psi, respectively, the radius of the sphere is determined for each pressure to set the mass of contained explosion gas to 35 kg. The material properties of explosion gas are set to be the ones of KM propellant combustion gas under normal condition. To reduce the effort and time required for a complex three-dimensional modeling, the flowfield is approximated to axismmetry. Calculations are performed for all three initial pressure conditions, and the analysis of the result is given for 1500 psi which is expected to be the worst case. The maximum pressure is 3.5 psig while the minimum pressure is -1.2 psig on the outer wall of MCC, and the maximum pressure difference between the inner and outer walls of protection wall amounts to 3.0 psi.

• 대한조선학회논문집
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• 제33권3호
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• pp.35-47
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• 1996

포텐셜을 기저로 하는 판요소법을 사용하여 자유 표면이 존재하는 유동장에서 일정 속도로 전진하는 3차원 물체의 형상을 설계하였다. 설계 방법으로는 원하는 압력 분포를 경계 조건으로 부여하고 이를 만족하는 물체 형상을 찾아내는 역해석법(inverse method)을 사용하였다. 즉, 주어진 압력으로부터 물체 표면에 분포된 법선 다이폴의 세기인 포텐셜 값을 결정하게 되며, 이는 물체 표면에 대한 Dirichlet형태의 경계 조건으로서 Green의 정리로부터 유도된 적분 방정식을 해석하게 된다. 전체 속도 포텐셜은 기본 유동인 선속에 대한 성분과 선제에 의하여 교란되는 성분으로 구성되어진다고 가정하였으며, 교란 포텐셜을 사용하여 선형화된 자유 표면 경계 조건을 적용하였다. 적분 방정식에 대한 수치 해석을 위해 물체 표면에 법선 다이폴과 Rankine 쏘오스를 분포하였으며, 자유 표면에는 Rankine 쏘오스를 분포하고 4점 유한 차분법을 사용하여 자유 표면 경계 조건이 만족되도록 하였다. 해로서 얻어지는 각 판요소에서의 Rankine 쏘오스의 세기는 가상의 유동 출입량으로서 형상 수정항으로 사용되었다. 몰수 회전 타원체의 형상 설계에 대하여 본 설계법을 적용한 결과 무한 수심에서나 조파 상태에서 $4{\sim}6$회의 반복 계산으로 충분히 수렴된 해를 얻을 수 있었다. 또한 자유 표면을 가르고 전진하는 Wigley 수학적 선형에 대한 형상 설계를 수행하여 만족스러운 결과를 얻어내었으며, 얻어진 수치해는 매우 안정적이고 빠른 수렴성을 보였다. 선형의 우열 비교를 통해 조파 저항을 감소시킬 수 있는 압력 분포의 형태를 파악하였으며, 이를 바탕으로 조파 저항의 관점에서의 5500TEU급 콘테이너 운반선의 설계를 수행하였다. 설계되어진 새로운 선형은 조파 저항의 관점에서 기존의 선형보다 계산과 실험에서 모두 우수하게 개량된 것으로 나타났다.

• 한국해안·해양공학회논문집
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• 제23권3호
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• pp.258-264
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• 2011

혼성제 케이슨에 작용하는 파력의 불확실성을 확률론적으로 해석할 수 있는 MCS 기법을 제시하였다. 수평파력 및 양력에 대한 확률론적 산정모형을 파력 산정에 사용되는 최대파고의 확률적 특성의 함수로 수립하였다. 파력이 극치분포를 따른다는 가정하에 Goda 식으로부터 산정된 수평파력과 양력에 대한 상대파력의 개념으로 파력의 거동특성을 해석하였다. 이중절단형 정규분포를 이용하는 MCS 기법을 이용하여 축척모수와 형상모수의 불확실성을 고려하였다. 최대설계파고의 초과확률에 따라 상대파력의 평균과 분산을 정량적으로 산정하였다. 해석 결과에 의하면 초과확률이 커짐에 따라 수평파력 및 양력에 대한 상대파력의 평균은 일정하게 감소된다. 특히 양력에 대한 상대 파력은 그 평균값이 수평파력의 평균보다 크고 변동계수는 작게 산정되었다. 이는 동일조건의 초과수준에서 양력에 대한 불확실성이 상대적으로 수평파력의 불확실성보다 작다는 것을 의미한다. 따라서 본 연구의 결과는 파력의 불확실성에 대한 통계적 거동특성을 요구하는 신뢰성 설계 등에서 유용하게 이용될 수 있다.

• Journal of Mechanical Science and Technology
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• 제20권2호
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• pp.286-294
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• 2006

Flows in a ramjet inlet is simulated for the study of the rocket-ramjet transition. The flow is unsteady, two-dimensional axisymmetric, compressible and turbulent. Double time marching method is used for the unsteady calculation and HLLC method is used as a higher order MUSCL method. As for turbulent calculation, $\kappa-\omega$ SST model is used for more accurate viscous calculations. Sinusoidal pressure perturbation is given at the exit and the flow fields at the inlet is studied. The cruise condition as well as the ground test condition are considered. The pressure level for the ground test condition is relatively low and the effect of the pressure perturbation at the combustion chamber is small. The normal shock at the cruise condition is very sensitive to the pressure perturbation and can be easily detached from the cowl when the exit pressure is relatively high. The sudden decrease in the mass flux is observed when the inlet flow becomes subcritical, which can make the inlet incapable. The amplitude of travelling pressure waves becomes larger as the downstream pressure increases, and the wavelength becomes shorter as Mach number increases. The phase difference of the travelling perturbed pressure wave in space is 180 degree.

• 대한조선학회논문집
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• 제33권1호
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• pp.1-8
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• 1996

3차원 날개면이 부착된 복합지지형 고속선의 정상상태에서의 조파저항을 포텐셜 기저 판요소법으로 해석하였다. 계산에 사용된 고속선은 물 속에 잠겨있는 몸체와 몸체의 중간 및 후방에 붙어 있는 3차원 날개면과 수면을 관통하는 앞, 뒤의 스트럿트로 구성되었다. 물체 표면(몸체, 날개면 및 스트럿트)에는 쏘오스와 다이폴을, 자유표면에는 쏘오스를 분포하였고, 선형화된 자유표면 조건과 방사조건을 만족시키기 위해 4점 유한차분을 이용하였으며, 날개면의 유동해석을 위해 준압력 Kutta조건(semi-linear pressure Kutta condition)을 적용하였다. 패널사이의 틈새 문제를 개선하기 위해 비 평면성이 고려된 쌍곡면 판요소법을 적용하여 각 선체 표면에서의 수치 계산 정도를 높이고자 하였다. 수치 계산 결과는 회류수조에서 모형 시험을 수행한 결과와 비교하였으며, 이로부터 본 연구에서 개발된 수치 계산법은 고속선의 최적 선형 개발에 이용 가능한 도구가 될 수 있는 것으로 나타났다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1018-1021
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• 2007

This paper explores the use of BEM based NAH to reconstruct the surface vibration of a plate in a rectangular finite cavity, in which the distances between sensors and the nearest points on the source surface are not equal. In such circumstances, different degree of information on propagating and non-propagating wave components will be detected by sensors at different positions, as well as the influence of measurement noise will vary significantly from the nearest points of measurement to the farthest ones. On the other hand, the condition number of the vibro-acoustic transfer function matrix relating normal surface velocities and field pressures will becomes high, numerically indicating an increase of linear dependency between rows of transfer function matrix. The combination of poor measurement and high condition number will result inaccurate reconstruction. Therefore, one approach to be investigated in this work is to select the measurement positions in such ways that reduce measurement redundancy, as it indicated by the condition number. The improvement is found to be significant in the numerical simulations utilizing two different criterions, spanning from over-determined to under-determined cases, and in the validation experiment.

• 한국패션뷰티학회지
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• 제1권1호
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• pp.133-142
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• 2003

As you see, there's no difference of the hair's before and after Magic straight permanent on the example A's hair's thickness, the rate of the tense and the C's rate of the tense, but we can find that there are a lot of difference of the A's strength of the hair, the B's hair's thickness, the strength of the hair, the rate of the tense, the C's hair's thickness, and the strength of the hair on the before and after the Magic straight permanent. That is to say, there are more damage on the condition of normal hair than the one after the Magic straight permanent. On the change of the hair's physical character, before the permanent, the hair's schedule was regular and had the healthy head skin of clear mutual boundary But after the Magic straight permanent wave, the hair's schedule changed to unregural, had unclear mutual boundary of the head skin and the schedule was taken off so the cortex showed up and so on, every condition of the damage was very heavy. On the effect of the treatment, even though it gaves the worth condition of the hair, after the Magic straight permanent formally the change of the hair gives the beautiful straight.