• 한국산학기술학회논문지
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• 제11권2호
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• pp.449-454
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• 2010

본 논문은 균질유동모델을 적용하여 단열 모세관내 R600a의 유동 특성을 이론적으로 조사하였다. 이 모델은 시뮬레이션 해석에 필요한 기본적인 질량, 에너지, 운동량 방정식에 근거하고 있다. 또한 2개의 마찰인자와 점성계수모델을 이용하여 유동특성을 조사하였다. R600a의 열역학 및 전달 물성치는 EES 물성치 코드를 이용하여 계산하였다. 작동변수들에 대한 기초 설계자료를 제공하고자 단열 모세관내 R600a의 유동 특성을 분석하였다. 본 연구의 작동변수에는 응축온도, 증발온도, 과냉각도, 모세관의 직경이 있다. 주요 결과를 요약하면 다음과 같다. R600a용 단열 모세관내 응축온도, 증발온도, 과냉각도, 관직경은 모세관 전체길이에 영향을 준다. 즉 R600a용 모세관 전체길이는 식(15)와 같은 상관식으로 나타낸다.

• 접착 및 계면
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• 제7권4호
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• pp.1-9
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• 2006

The single lap joint is the most studied joint in the literature in terms of both theory and practice. It is easy to manufacture and the lap shear strength is a useful value for strength assessment and quality control. Simple design rules exist such as the one present in standard ASTM 1002 or in a recent paper by Adams and Davies. The main factors that have an influence on the lap shear strength are the type of adhesive, i.e. ductile or brittle, the adherend yield strength and the overlap length. The overlap increases the shear strength almost linearly if the adhesive is sufficiently ductile and the adherend does not yield. For substrates that yield, a plateau is reached for a certain value of overlap corresponding to the yielding of the adherend. For intermediate or brittle adhesives, the analysis is more complex and needs further investigation. In order to quantify the influence of the adhesive, the adherend and the overlap on the lap shear strength, the experimental design technique of Taguchi was used. An experimental matrix of 27 tests was designed and each test was repeated three times. The influence of each variable could be assessed as well as the interactions between them using the statistical software Statview. The results show that the most important variable on the lap shear strength is the overlap length followed by the type of adherend.

• 수산해양교육연구
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• 제21권2호
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• pp.230-236
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• 2009

2003년 2월부터 2004년 1월까지 잔라북도 고창군 심원면 대죽도 부근에 서식하는 바지락의 성장에 관한 조사결과를 요약하면 다음과 같다. 1. 바지락의 패각에 나타난 윤문은 연1회 형성되며 윤문형성시기는 1월에서 3월사이로 조사되었다 2. 초륜 형성 시기는 19개월(1.58년)로 나타났다. 3. 각고에 대한 각장,각폭 및 총중량사이의 상대성장관계식은 각각 ${\bullet}$ SL=1.0027SH+5.812, ${\bullet}$ SW=0.5120H+1.2849, ${\bullet}\;TW=2.8x10^{-3}SH^{2.3648}$ 이었다. 4. 연령에 대한 각고와 총중량으로부터 구한 von Bertalanffy성장식은 ${\bullet}\;SH_t=42.83(1-e^{-0.4595(t-0.591)})$이고, ${\bullet}\;TW_t=20.17(1-e^{-0.4595(t-0.59)})^{2.3648}$이다.

• Journal of Forest and Environmental Science
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• 제30권4호
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• pp.322-330
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• 2014

This study was conducted during May to September in 2012 to investigate the distribution and diversity of beetles in Mt. Jangsan (634 m) located near Busan, Republic of Korea. The collection of beetles was repeated 11 times in the four areas classified according to altitudes 200 m, 400 m, 600 m, and over 600 m (approximately) on the south and north slopes of Mt. Jangsan. A total of 12 families, 20 species, and 4,343 individual beetles were collected. In the southern slopes, a total of 12 families, 20 species, and 2,264 individuals were collected, whereas a total of 12 families, 20 species, and 2,079 individuals on the northern slopes were captured. The monthly emergence of beetles was the highest in August at 651 individuals followed by 516 individuals in September, 496 individuals in July, 364 individuals in Jun, 237 individuals in May. In the northern slopes, the monthly emergence of beetles was the highest in August as 591 individuals followed by 512 individuals in September, 443 individuals in July, 321 individuals in June, and 212 individuals in May. On the southern slopes, the species diversity index, evenness index, and dominance value were 0.950, 0.730, and 0.181, respectively, while in the northern slopes, the species diversity index, evenness index, and dominance index were 0.946, 0.727, and 0.182, respectively. In the both slopes, the species diversity index and evenness index were the highest in May, while dominance index was the highest in September. This study lays the groundwork for further monitoring of these sites and others through the region for environmental changes using the indicator species.

• 한국전산구조공학회논문집
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• 제27권5호
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• pp.379-384
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• 2014

본 논문은 갠트리 크레인의 설계를 위해 컨테이너 하역작업 시 특정하중 조건하의 RTGC(Rubber Tired Gantry Crane)의 동적거동과 그에 따른 윤하중을 분석한 내용을 기술하고 있다. 먼저 RTGC의 동적거동을 살펴보기 위해 거대 구조물인 크레인의 유한요소 모델을 개발하고 고유진동수와 고유모드의 모달시험결과를 이용하여 유한요소모델을 검증하였다. RTGC의 기타 부속품은 3차원 CAD모델링을 통해 다물체 동역학해석 소프트웨어인 ADAMS에서 강체로 모델링하였다. 본 연구에서 하중 조건은 일반적인 컨테이너의 이송조건(OP1)과 외부부하조건 없이 단순히 트롤리를 이용하여 컨테이너를 하역하는 2가지 경우로 고려하였다. 해석 결과 RTGC의 컨테이너 작업 시 발생하는 크레인의 진동은 거대 구조물의 강성과 변형에 주로 기인함을 확인하였으며 이러한 크레인의 진동은 RTGC의 움직임을 발생시켜 컨테이너 하역작업 불능 등의 거동을 발생시킬 수 있음을 분석할 수 있었다.

• 논리연구
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• 제8권2호
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• pp.59-84
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• 2005

조건문의 확률은 조건부 확률과 같을 수 없음을 보이는 루이스의 '사소함 결과'(the triviality results)는 널리 알려져 있다. 하지만 이 증명의 정확한 구조와 그 의미를 파악하기란 그다지 쉽지 않다. 이 논문에서는 먼저 루이스 증명의 한 형태가 제시되고 왜 조건문의 확률은 조건부 확률과 같을 수 없는지에 대해 한 가지 설명이 제공된다. 이와 아울러 이런 결과가 갖는 철학적 함축이 무엇인지가 논의된다. A일 경우 C일 조건부 확률은 A가 성립할 경우 C가 성립할 가능성이 어느 정도인지에 관한 것으로, 이 점은 조건부 확률의 정의인 등식 Pr(C|A)= Pr(A & C) / Pr(A)에 잘 반영되어 있다. 조건부 확률이 갖는 이런 독특한 성질과 조건부 확률과 언제나 같은 확률을 갖는 명제를 찾으려는 노력이 허사로 끝나게 마련이라는 점은 서로 밀접한 연관이 있어 보인다. 만약 이 점이 옳다면, 우리는 조건문은 그냥 주장과는 아주 다른 조건부 주장을 표현한다고 보아야 하며, 조건부 주장은 진리조건을 갖지 않는, 사이비 주장이라는 점을 받아들여야 할지도 모르겠다.

• 대한기계학회논문집B
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• 제29권6호
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• pp.737-746
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• 2005

The present study investigates heat/mass transfer and flow characteristics in a ribbed rotating passage with turning region. The duct has an aspect ratio (W/H) of 0.5 and a hydraulic diameter ($D_h$) of 26.67 mm. Rib turbulators are attached in the cross arrangement on the leading and trailing surfaces of the passage. The ribs have a rectangular cross section of $2\;mm\;(e){\times}\;mm\;(w)$ and an attack angle of $70^{\circ}$. The pitch-to-rib height ratio (p/e) is 7.5, and the rib height-to-hydraulic diameter ratio ($e/D_h$) is 0.075. The rotation number ranges from 0.0 to 0.20 while the Reynolds number is constant at 10,000. To verify the heat/mass transfer augmentation, internal flow structures are calculated for the same conditions using a commercial code FLUENT 6.1. The heat transfer data of the smooth duct for various Ro numbers agree well with not only the McAdams correlation but also the previous studies. The cross-rib turbulators significantly enhance heat/mass transfer in the passage by disturbing the main flow near the surfaces and generating one asymmetric cell of secondary flow skewing along the ribs. Because the secondary flow is induced in the first-pass and turning region, heat/mass transfer discrepancy is observed in the second-pass even for the stationary case. When the passage rotates, heat/mass transfer and flow phenomena change. Especially, the effect of rotation is more dominant than the effect of the ribs at the higher rotation number in the upstream of the second-pass.

• Clinical and Experimental Reproductive Medicine
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• 제44권1호
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• pp.40-46
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• 2017

Objective: To describe in vitro development of human embryos derived from an individual with a homozygous pathogenic variant in NLRP7 (19q13.42) and recurrent hydatidiform mole (HM), an autosomal recessive condition thought to occur secondary to an oocyte defect. Methods: A patient with five consecutive HM pregnancies was genomically evaluated via next generation sequencing followed by controlled ovarian hyperstimulation, in vitro fertilization (IVF) with intracytoplasmic sperm injection, embryo culture, and preimplantation genetic screening. Findings in NLRP7 were recorded and embryo culture and biopsy data were tabulated as a function of parental origin for any identified ploidy error. Results: The patient was found to have a pathogenic variant in NLRP7 (c.2810+2T>G) in a homozygous state. Fifteen oocytes were retrieved and 10 embryos were available after fertilization via intracytoplasmic sperm injection. Developmental arrest was noted for all 10 embryos after 144 hours in culture, thus no transfer was possible. These non-viable embryos were evaluated by karyomapping and all were diploid biparental; two were euploid and eight had various aneuploidies all of maternal origin. Conclusion: This is the first report of early human embryo development from a patient with any NLRP7 mutation. The pathogenic variant identified here resulted in global developmental arrest at or before blastocyst stage. Standard IVF should therefore be discouraged for such patients, who instead need to consider oocyte (or embryo) donation with IVF as preferred clinical methods to treat infertility.

• 한국패류학회지
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• 제7권1호
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• pp.1-11
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• 1991

Authors describe here five new species and three new subspecies of Korean Iand snail fauna. They are collected from the southern part of Korea including Ullungdo and Chejudo. The generic names of these new species and subspecies were discribed in the [ Il-lustrated Encyclopedia of fauna & flora of Korea V ol.32 Mollusca(I)]. The newly recorded species and subspecies are as follows:Genus Diplommatina Benson, 1849 Subgenus Sinica Mollendorff, 1885 Diplommatina(Sinica) paxillus changensis n. subsp. Diplommatina(Sinica) chejuensis n. sp.Genus Arinia H. & A. Adams, 1856 Arinia chejuensis n. sp.Authors describe here five new species and three new subspecies of Korean Iand snail fauna. They are collected from the southern part of Korea including Ullungdo and Chejudo. The generic names of these new species and subspecies were discribed in the [ Il-lustrated Encyclopedia of fauna & flora of Korea V ol.32 Mollusca(I)]. The newly recorded species and subspecies are as follows:Genus Diplommatina Benson, 1849 Subgenus Sinica Mollendorff, 1885 Diplommatina(Sinica) paxillus changensis n. subsp. Diplommatina(Sinica) chejuensis n. sp.Genus Cavernacmella Habe, 1942 cavernacmella coreana n. sp.Authors describe here five new species and three new subspecies of Korean Iand snail fauna. They are collected from the southern part of Korea including Ullungdo and Chejudo. The generic names of these new species and subspecies were discribed in the [ Il-lustrated Encyclopedia of fauna & flora of Korea V ol.32 Mollusca(I)]. The newly recorded species and subspecies are as follows:Genus Diplommatina Benson, 1849 Subgenus Sinica Mollendorff, 1885 Diplommatina(Sinica) paxillus changensis n. subsp. Diplommatina(Sinica) chejuensis n. sp.Genus Mirus Albers, 1850 Mirus junensis n. sp.Genus Paganizaptyx Kuroda, 1945 Paganizaptyx miyanagai ullungdoensis. subsp.Authors describe here five new species and three new subspecies of Korean Iand snail fauna. They are collected from the southern part of Korea including Ullungdo and Chejudo. The generic names of these new species and subspecies were discribed in the [ Il-lustrated Encyclopedia of fauna & flora of Korea V ol.32 Mollusca(I)]. The newly recorded species and subspecies are as follows:Genus Diplommatina Benson, 1849 Subgenus Sinica Mollendorff, 1885 Diplommatina(Sinica) paxillus changensis n. subsp. Diplommatina(Sinica) chejuensis n. sp.Genus Ratinella Shuttleworth, 1877 Retinella radiatula coreana n. subsp.Genus Sitalina Thiele, 1931 Sitalina chejuensis n. sp.

• Smart Structures and Systems
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• 제25권5호
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• pp.559-567
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• 2020

Vibration at the tip of various flexible manipulators may affect their operation accuracy and work efficiency. To suppress such vibrations, the feasibility of using MFC actuators and sensors is investigated in this paper. Considering the convergence of the famous filtered-x least mean square (FXLMS) algorithm could not be guaranteed while it is employed for vibration suppression of plants with varying secondary path, this paper proposes a new multiple model switching adaptive control algorithm to implement the real time active vibration suppression tests with a new multiple switching strategy. The new switching strategy is based on a cost function with reconstructed error signal and disturbance signal instead of the error signal from the error sensor. And from a robustness perspective, a new variable step-size sign algorithm (VSSA) based FXLMS algorithm is proposed to improve the convergence rate. A cantilever beam with varying tip mass is employed as flexible manipulator model. MFC layers are attached on both sides of it as sensors and actuators. A co-simulation platform was built using ADAMS and MATLAB to test the feasibility of the proposed algorithms. And an experimental platform was constructed to verify the effectiveness of MFC actuators and sensors and the real-time vibration control performance. Simulation and experiment results show that the proposed FXLMS algorithm based multiple model adaptive control approach has good convergence performance under varying load conditions for the flexible cantilever beam, and the proposed FX-VSSA-LMS algorithm based multiple model adaptive control algorithm has the best vibration suppression performance.