• Journal of the Korean Geotechnical Society
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• v.19 no.1
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• pp.229-236
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• 2003

Ultrasonic propagation velocities of both the dilatational and shear waves through the weathered tuff soil sampled from the area tying between Ulanbator and Beijing were measured under temperature condition of near subzero by means of sing-around method. After comparing the results with obtained data on unfrozen water content, a linear relation between velocities and unfrozen water content was performed with high coefficient value. Experimental results of two kinds of rather uniform materials, namely, glass-beads and silica micro-beads, testified the similar linear relations. In addition, the change rate of dilatational wave velocities with the change of volumetric unfrozen water content was not dependent on soil type. Although a rational theory of the ultrasonic velocities dependence on the unfrozen water content is not yet proposed, the presented empirical relationships may suggest the appropriate evaluation to the effect of unfrozen water on dynamic characteristics of frozen soil.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.714-718
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• 1996

The interference phenomenonof a dynamic crack propagation in a inclined DEN(double edge notched) specimen has been investigated by using the dynamic photoelasticity. One crack initiated by static loading is propagated dynamically and experiences a mixed mode condition(interference) as the crack approaches to the inclined edge notch. We use the overdeterministic least-square method to extract dynamic $K_{Id}$ K sub IId/and .sigma. $_{ox}$from the recorded dynamic photoelastic pattern surounding a running crack. The evaluated $K_{Id}$ $K_{IId}$and .sigma. $_{ox}$together with the crack propagation velocity estimate the dynamic crack interference phenomenonenonon

• Journal of the KSME
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• v.31 no.4
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• pp.332-340
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• 1991

본 글에서는 속이 찬 실린더(solid cylinder)에서의 비대칭 탄성파전파 문제를 풀기 위한 해석적 방법의 일부를 소개하고자 한다. 속이찬 실린더에 있어서는 측면벽의 경계조건에 상관없이 평 판에서의 Fourier 시리즈와 유사한 단순해가 존재하지 않는다고 밝혀져 왔다(1). 그러나 최근 발표된 본인의 논문(2)에서 지적된 것처럼, 매우 특별한 측면 경계조건을 갖는 경우에만 정해가 존재한다. 특히 탄성파전파에 관한 한, 이러한 정해는 물리적으로 볼 때 팽창파(dilatational wave)와 전단파(shear wave)가 서로 얽히지 않는 상태에 해당되기 때문에, 소위 "비혼합 해(uncoupled solution)"라 불린다. 이 "비혼합해(uncoupled solution)"의 실제 사용 예를 들면, 상술된 바와 같이 일반적인 측면 경계조건을 갖는 속이 찬 실린더 문제를 풀기 위한 시도함 수(trial function)로 사용될 수 있을 것이다. 주지하는 바와 같이 자유측면벽(traction-free cylindrical wall)을 갖는 속이 찬 실린더는 공학적으로 매우 중요한 구조요소이다. 이 경우에는 측면벽의 경계조건으로 말미암아, 해가 정해의 형태로 존재하지 않는다. 특히 이 구조물에서의 탄성파전파 문제를 다루고자 할 때, 먼저 분산관계식(dispersion relation)을 구한 다음, 이를 이 용해 경계문제를 푸는 것이 상용적으로 사용되는 방법이다. 이 분산 관계식은 파장과 주파수 와의 관계를 나타내는 것으로, 그 복잡성으로 말미암아 이 식을 사용되는 수치해법으로 정확하게 구하는 것은 거의 불가능하다. 따라서, 본 글에서는 특별한 측면벽을 갖는 속이 찬 실린더의 비혼합해를 활용하여 자유측면벽을 갖는 속이 찬 실린더의 분산관계식(pochhammer의 분산관 계식이라 불린다)을 구하는 법을 설명하고자 한다. 이를 위해 비혼합해가 존재하는 측면경계조 건에 대해 먼저 살펴보고자 한다.조 건에 대해 먼저 살펴보고자 한다.

• The Journal of Internal Korean Medicine
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• v.39 no.3
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• pp.389-404
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• 2018

Objective: The aim of this study was to investigate acupuncture therapy for post-stroke cognitive disorder to suggest the methods of a study about acupuncture therapy. Methods: Several academic databases were used in this study, including National Digital Science Library (NDSL), National Assembly Library of Korea, Korean Traditional Knowledge Portal, Research Information Sharing Service (RISS), Korean studies Information Service System (KISS), Korean Medical Database (KMBASE), Korea Med, Oriental Medicine Advanced Searching Integrated System (OASIS), PubMed, MEDLINE with Full Text, and China National Knowledge Infrastructure (CNKI). Keywords used were "중풍", "뇌졸중", "인지장애", "침", "acupuncture", and "cognitive disorder". Results: Ultimately, 28 papers were investigated. that were mainly published in 2012 and 2016. Of these, More than two-thirds received a score of one or less on the Jadad scale. Acupuncture points such as GV20, GV24, PC6, EX-HN1, SP6, and GV26 were most frequently used. The treatment duration was mostly 30 minutes or less, and the treatment cycle was mostly for four weeks. Dilatational wave was generally used in pulse wave form, and amplitude of electricity was increased until patients were able to endure. G6805 was generally used in electric acupuncture apparatus. According to results of acupuncture treatment, assessments such as the MMSE (Mini Mental State Examination) and the Montreal Cognitive Function Assessment Scale (MoCA) showed statistically significant improvements in 28 studies. Conclusions: Future research is needed to standardize the treatment of acupuncture, and more diversified high quality papers should be published to help clarify the therapeutic effects of acupuncture and the mechanisms of cognitive disorder post-stroke.