• 한국강구조학회 논문집
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• 제11권1호통권38호
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• pp.43-54
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• 1999

공장설비구조물, 트러스, 해양구조물 등에 사용되는 원형강관 분기이음이 많이 사용되고 있다. 강관구조물은 폐단면으로 되어 있기 때문에 개단면인 H, L-형강에 비하여 역학적으로 유리하다. 격점부에서 주요한 문제는 압축을 받는 지관이 압축력에 의하여 부재가 좌굴하기 이전에 강관 분기이음부에서 국부좌굴에 의한 구조체 전체가 불안정하게 된다. 일반적으로 상기와 같은 격점부의 응력분포 및 변형성상이 복잡하여 해석적으로 정밀 해를 구하기가 어렵기 때문에 실험에 기초한 단순한 해석법을 통하여 접합부의 항복내력에 관한 실용식을 제안할 필요가 있다. 본 연구에서는 X형 강관 격점부에 관하여 주관의 직경비(d/D) 및 주관경과 두께비(D/T)을 주 변수로 하여 내력 및 변형성상에 관하여 실험을 진행하고 단순한 해석법인 링해석법을 통하여 항복하중에 관한 예측식을 제안하였다.

• 식물분류학회지
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• 제42권4호
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• pp.330-334
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• 2012

골풀과의 골풀속에 속하는 Juncus fauriei L$\acute{e}$v. & Vaniot는 일본과 러시아에 분포한다고 알려져 있는 종인데, 강원도의 하조대 해안가 사구 습지에서 이를 발견하여 보고하고자 한다. 이 식물은 줄기의 단면이 납작하고 주로 나선상으로 꼬여있고, 화피편의 가장자리가 검은색을 띄는 특징으로 국내 골풀속 내의 section Juncotypus에 속하는 근연 종인, J. decipiens (골풀), J. setchuensis (푸른갯골풀), J. haenkei (갯골풀), J. brachyspathus (참골풀)와 확연하게 구분 된다. 이러한 형태적 특징에 따라 국명을 '검정납작골풀'로 신칭하였고, 이 분류군의 사진 및 형질에 대한 기재, 근연 분류군들과 구분할 수 있는 검색표를 제시하였다.

• 한국지반환경공학회 논문집
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• 제4권2호
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• pp.57-64
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• 2003

좁고 길게 굴착된 고랑형태의 되메움 지반의 토압에 관한 해석에 널리 사용되어져 오던 Marston(1913), Spangller(1982) 이론은 R.L. Handy(1985)가 굴착벽면과 되메움 흙과의 상호작용에 의한 최소주응력의 고리를 연결한 최소주응력 아치로서 표현함으로 보다 명확한 설명이 가능하게 되었다. 이후 C.G. Kellogg(1993)는 지금까지 주로 수직하게 대칭된 공간만을 대상으로 논의 되오던 되메움 공간형태를 경사지게 대칭된 공간형태에 대하여 연구를 확장하였다. 발표된 C.G. Kellogg(1993) 이론식은 이론식의 도출 과정에 있어 경사 벽면의 마찰저항이 아닌 경사단면 저부에서 연직한 되메움 흙 자체의 내부 마찰의 크기로서 가정하였다. 본 연구는 C.G. Kellogg가 적용한 경사단면 저부에서 연직한 면의 마찰저항은 경사진 단면에서의 마찰저항과는 다른 크기를 갖을 것이며 이 크기는 토압 산출에 영향을 미칠것으로 판단되어 이를 실내모형 토조실험, C.G Kellogg(1993) 이론식, 수치해석, 실제 경사벽면에 미치는 마찰저항을 고려한 수정된 C.G. Kellogg 이론식으로 규명하고자 하였다.

• ETRI Journal
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• 제42권5호
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• pp.781-789
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• 2020

In this study, an E-band low-noise amplifier (LNA) monolithic microwave integrated circuit (MMIC) has been designed using silicon-germanium 130-nm bipolar complementary metal-oxide-semiconductor technology to suppress unwanted signal gain outside operating frequencies and improve the signal gain and noise figures at operating frequencies. The proposed impedance-controllable filter has series (R_s) and parallel (R_p) resistors instead of a conventional inductor-capacitor (L-C) filter without any resistor in an interstage matching circuit. Using the impedance-controllable filter instead of the conventional L-C filter, the unwanted high signal gains of the designed E-band LNA at frequencies of 54 GHz to 57 GHz are suppressed by 8 dB to 12 dB from 24 dB to 26 dB to 12 dB to 18 dB. The small-signal gain S₂₁ at the operating frequencies of 70 GHz to 95 GHz are only decreased by 1.4 dB to 2.4 dB from 21.6 dB to 25.4 dB to 19.2 dB to 24.0 dB. The fabricated E-band LNA MMIC with the proposed filter has a measured S₂₁ of 16 dB to 21 dB, input matching (S₁₁) of -14 dB to -5 dB, and output matching (S₂₂) of -19 dB to -4 dB at E-band operating frequencies of 70 GHz to 95 GHz.

• Advanced Composite Materials
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• 제17권1호
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• pp.1-23
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• 2008

Robotized filament winding technology involves a robot that winds a roving impregnated by resin on a die along the directions of stresses to which the work-piece is submitted in applications. The robot moves a deposition head along a winding trajectory in order to deposit roving. The trajectory planning is a very critical aspect of robotized filament winding technology, since it is responsible for both the tension constancy and the winding time. The present work shows two original rules to plan the winding trajectory of structural parts, whose shape is obtained by sweeping a full section around a 3D curve that must be closed and not crossing in order to assure a continuous winding. The first rule plans the winding trajectory by approximating the part 3D shape with straight lines; it is called the discretized rule. The second rule defines the winding trajectory simply by offsetting a 3D curve that reproduces the part 3D shape, of a defined distance; it is called the offset rule. The two rules have been compared in terms of roving tension and winding time. The present work shows how the offset rule enables achievement of both the required aims: to manufacture parts of high structural performances by keeping the tension on the roving near to the nominal value and to markedly decrease the winding time. This is the first step towards the optimization of the robotized filament winding technology.

• 한국지형학회지
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• 제20권1호
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• pp.57-74
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• 2013

순천시 와온마을 일대에는 해발고도 8.3m의 단구가 발달하고 있다. 단구면 내부에는 여러 단의 원력층 (4.3m, 5.8m, 6.3m) 뿐만 아니라 현재와는 다른 환경에서 퇴적된 사질층을 포함하고 있어 과거 해수준에 대한 추정과 함께, 형성 당시의 기후 환경적 특색을 파악할 수 있다. 이를 파악하기 위해 단면기술, 입도분석, XRD, 박편분석을 시도하였으며, 다른 지역과의 비교를 통해 상대적인 편년을 추정하였다. 분석결과 와온단면은 최후간빙기(MIS 5)보다는 좀 더 근자에 형성되었을 것으로 추정되며, 이 시기에 다양한 토양학적 특징을 형성한 것으로 보인다.

• Journal of Ecology and Environment
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• 제41권1호
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• pp.9-18
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• 2017

Background: Species in the heterokont genus Synura are colonial and have silica scales whose ultrastructural characteristics are used for classification. We examined the ultrastructure of silica scales and molecular data (nuclear SSU rDNA and LSU rDNA, and plastid rbcL sequences) to better understand the taxonomy and phylogeny within the section Petersenianae of genus Synura. In addition, we report the first finding of newly recorded Synura species from Korea. Results: We identified all species by examination of scale ultrastructure using scanning and transmission electron microscopy (SEM and TEM). Three newly recorded species from Korea, Synura americana, Synura conopea, and Synura truttae were described based on morphological characters, such as cell size, scale shape, scale size, keel shape, number of struts, distance between struts, degree of interconnections between struts, size of base plate pores, keel pores, base plate hole, and posterior rim. The scales of the newly recorded species, which belong to the section Petersenianae, have a well-developed keel and a characteristic number of struts on the base plate. We performed molecular phylogenetic analyses based on sequence data from three genes in 32 strains (including three outgroup species). The results provided strong statistical support that the section Petersenianae was monophyletic, and that all taxa within this section had well-developed keels and a defined number of struts on the base plate. Conclusions: The phylogenetic tree based on sequence data of three genes was congruent with the data on scale ultrastructure. The resulting phylogenetic tree strongly supported the existence of the section Petersenianae. In addition, we propose newly recorded Synura species from Korea based on phylogenetic analyses and morphological characters: S. americana, S. conopea, and S. truttae.

• Asian-Australasian Journal of Animal Sciences
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• 제18권10호
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• pp.1379-1382
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• 2005

High prolificacy in Garole sheep is due to existence of FecB mutation in an autosomal gene, bone morphogenetic protein receptor. The mutation enhances ovulation rate and in turn litter size in Garole sheep. Garole sires were crossed with non-prolific Malpura ewes with the aim to introduce prolificacy into Garole${\times}$Malpura (G${\times}$M) crosses through FecB introgression programme. In the present study, the effect of carrying booroola allele on litter size and live body weight was analyzed. The average litter size at birth was found to be 1.87 and 1.48 in the Garole and the G${\times}$M crosses, respectively. At weaning, 6-month, 9-month and 12-month of age, body weights were not affected by the presence of booroola allele (p>0.05); however, a significant effect (p<0.05) was found on body weight at birth in G${\times}$M crosses. In Garole sheep, no significant effect of FecB was observed on live weights in any age group. The interaction between the genetic group and the FecB genotype was also found to be non-significant.

• 한국환경과학회지
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• 제11권2호
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• pp.121-130
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• 2002

Compare to investigate the taxonomic utility of infragenera system and interspecific of Asian Geranium, we examined the fruit and seed morphology from 35 taxa. The fruit shape and seed's dispersal way did so that may divide subgenus or some part section to do could reason evolutionary trends. That is, at seed dispersal, the awns of section Geranium of subgenus Geranium, ramains attached at the top of rostrum, though fairy easily broken off, because seed increases awn's elasticity by diffusive way, it is long characteristic seed\`s dispersal distance, and subgenus Robertium observed that seed dispersal distance is short because it is no awn's elasticity by way that seed dispersal is gone as awn drops with rostrum. Also, section Geranium of subgenus Geranium and subgenus Robertium act role that awn keeps temporarily breed swerving with mericarp instead of bristle because section Tuberosa of subgenus Geranium is not bristled function that keep temporarily breed because mericarp bristled on base at seed dispersal do while. Therefore, is thought that is talon that when consider formation's development and function regarding this seed dispersal function, subgenus Geraniuum evolves more than subgenus Robertium. Seed morphology can divide by 2 subgenera(Geranium, Robertium) according to pattern of seed coat. and Seed's morphology characteristic(whole shape, color, form of seed apical and base, micropyle area, hilum area, chalaza, and position of seed hilum area), can distinguish some species, but is thought that is not reasonable as for discernment characteristic form and nature by repetition of characteristic form and nature. Especially, infrasection do in fruit and seed's morphology that is handling in this research that know to argue classification system and relationship by repetition of characteristic form and nature difficult. To all reliable truth, cytological, ecological, embryology, and molecular genetics research about talon is considered that should be achieved section Geranium that do not handle yet.

• 한국임상수의학회지
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• 제24권2호
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• pp.160-163
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• 2007

Patients often present with spontaneous bleeding, or a bleeding disorder may be discovered when an otherwise healthy dog develops marked bleeding during or after surgery. In this study, we were aimed to elucidate whether the cesarean section in dogs has influence on the coagulation profiles. And we gained the normal data on a panel of screening laboratory tests which allow accurate characterization of a hemostatic defects in dogs. Of the 20 healthy adult dogs, buccal mucosa bleeding time (BMBT) was $83.0{\pm}10.5$ seconds, platelet count was $24.0{\pm}3.5{\times}10^4/{\mu}l$, activated partial thromboplastin time (APTT) was $8.8{\pm}2.0$ seconds, the concentration of fibrinogen was $288.5{\pm}77.9mg/dl$, and the concentration of fibrin degradation products (D-dimer) was <250.0 ng/ml. Coagulation profiles before and after cesarean section of 13 cesarean sectioned dogs were in the normal range and there were no statistical differences in coagulation profiles between normal dogs and cesarean sectioned dogs (p>0.05). The results suggested that labor and cesarean section in healthy dogs did not alter coagulation profiles.