• 한국공작기계학회논문집
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• 제17권6호
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• pp.124-131
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• 2008

There are many factors which affect the acoustical properties of a micro-speaker. Among the factors, the shape of the diaphragm is considered in this study. As an investigating method, the finite element methods and measurement techniques applied to study the acoustical properties according to diaphragm shape. In order to vary the stiffness of the diaphragm, the some patterns of comb teeth, such as the angle and the number of comb teeth, are applied to diaphragm. We can confirm that the change of the stiffness by the changing diaphragm shape affects the vibration and sound properties of the speaker. As a result, the reduction of the angle of the comb teeth increases the diaphragm stiffness and shifts the resonance frequency to a higher frequency range. The number of the comb teeth is related to the stiffness of the edge part.

• 한국전기전자재료학회논문지
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• 제24권11호
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• pp.920-924
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• 2011

ZnO crystals with belt and comb shapes were synthesized without any catalysts through a simple thermal oxidation of ZnS powder in alumina crucible under air atmosphere. X-ray diffraction (XRD) pattern revealed that the ZnO crystals had wurtzite structure of hexagonal phase. Energy dispersive x-ray (EDX) spectra showed that the ZnO was of high purity. In the cathodoluminescece spectra obtained for the ZnO crystals with belt and comb shapes, a strong ultraviolet emission centered at 380nm was observed, which indicates the ZnO crystal has high crystalline quality.

• KIEE International Transactions on Electrophysics and Applications
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• 제5C권6호
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• pp.264-269
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• 2005

The electrostatic comb drive actuator is one of the main building blocks in the field of micro electro-mechanical systems (MEMS). Most of the comb actuators presented previously have fingers that are rectangular in shape which produce a stable, constant force output during actuation. The use of sawtooth fixed fingers in a comb drive, which were presumed to produce an increasing force output with displacement due to the increased number of regions where fringing force, the driving force of comb actuators, appear. The dimensions of the sawtooth were derived from finite element analysis (FEA) of simplified finger models with sawtooth type fingers of various dimension and were compared to the rectangular finger model that showed that the sawtooth type fingers have $7\~9$ times stronger driving force. Finally, comb drive actuators with sawtooth type and rectangular fingers were fabricated and although the gap was bigger, the comb actuator with sawtooth type fingers showed about 1.7 times greater electrostatic force than the one with rectangular fingers at equal driving voltages. In conclusion, using the proposed sawtooth type comb fingers in a comb drive makes it possible to increase its displacement or reduce the driving voltage.

• 정보저장시스템학회논문집
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• 제10권1호
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• pp.23-26
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• 2014

In this paper, we present a novel approach for tuning the resonant frequency of torsionally driven vertical comb actuators. The tuning unit composed of thermal actuator, scissor mechanism and V-shape shaft enables continuous and reversible resonant frequency tuning. The proposed method is based on the stiffness alteration of the V-shape shaft. It is experimentally verified that the resonant frequency of the torsional microscanner is shifted up to 1.59 kHz from 1.51 kHz showing the maximum tuning ratio of 5.29%.

• ALGAE
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• 제37권1호
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• pp.15-32
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• 2022

Inspecting herbaria collections of Laurencia rigida highlighted frequent misidentifications between L. rigida and L. heteroclada f. decussata, two poorly studied taxa from Australia. Recent collections of DNA material, including from topotype material, allowed for re-examination of these two taxa using molecular techniques. Detailed morphological and molecular analyses based on two markers (rbcL and COI-5P) strongly supported these two taxa as being distinct from each other and requiring nomenclatural changes. Comprehensive morphological analyses highlighted features useful for accurate identifications. Interestingly, L. rigida was found to belong to the genus Palisada with evidence from both the morphology and molecular data. Therefore, this study proposed recognizing L. rigida as Palisada rigida comb. nov. Molecular data for L. heteroclada f. decussata on the other hand supported its separation from L. heteroclada, with too great a molecular distance to be considered a variety. Morphological characters that best separated P. rigida from L. decussata included seven characters; number of pericentral cells per vegetative axial segment, the presence of secondary pit connections, the presence of lenticular thickenings, tetrasporangia alignment, the presence of corps en cerise, holdfast morphology, and overall plant shape. Morphologically, L. heteroclada f. decussata was also separated from L. heteroclada, particularly by the following characteristics; ultimate branchlets morphologies, lower order branch lengths, primary axis and holdfast morphologies. Therefore, it was proposed that L. heteroclada f. decussata is recognized at a species level as L. decussata comb. et stat. nov.

• 한국응용곤충학회지
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• 제35권3호
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• pp.216-220
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• 1996

Drosophila simulans와 D. mauritiana는 동일 subgroup에 속하는 동포종으로, 전자는 전세계 분포종이며, 후자는 Mauritius 섬에만 서식하는 지역종이다. D. simulans의 성즐(sex comb)은 약 9.83개의 치열로 구성되어 있으며, D, mauritiana의 성즐 치열수는 약 12.90개 정도이다. D. simulans의 생식궁(genital arch)은 큰 반월형이며, D. mauritiana는 가는 막대형이다. 두 종간 성즐의 치열수와 생식궁의 형태적 차이에 미치는 X 염색체의 효과를 알아보기 위한 유전적 분석을 실시하였으며, 이를 위하여 X 염색체상 돌연변이 유전자들을 가지는 D. simulans 계통과 정상의 D. mauritiana 사이의 잡종 {TEX}$F_{1}${/TEX}을 부모계통과 역교배를 실시하여 얻은 자손들을 대상으로 상기 두가지 형질의 분석을 실시하였다. F1의 성즐 치열수는 평균 11.79개 정도였으며, 외부생식기의 일반적인 형태는 D. simulans와 D. mauritiana의 중간형이었다. 성즐의 치열수와 외부생식기의 주요 특징분석에서 X 염색체 효과에 따른 유의적인 차이는 거의 없는 것으로 나타났다.

• 한국응용곤충학회지
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• 제34권4호
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• pp.308-313
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• 1995

Drosophila melanogaster와 D. Simulan는 전세계적으로 분포하며, D. Sechellia 는 Africa의 Seychelles 제도에만 서식하는 지역종으로, 모두 D. melanogaster complex에 속하는 동포종이다. 이들 D. melanogaster complex 3종을 대상으로 종간 교배를 통한 잡종을 형성하여 성증(sex-bomb)과 생식궁(genital arch)의 표현형적 유연관계를 부모계통과 상호 비교하였다. 상기 3종들 사이의 교배를 통해 4가지 유형의 잡종 수컷을 얻었으며 이들은 모두 불임이었다. 성즐의 평균 치열 수는 D. melanogaster(OR)가 10.73개, D. sechellia(Ja)는 10.69개였으며, D. simulans($O_9$)에서는 8.35개였다. 종간 잡종의 치열수 분석으로 뚜렷한 성즐의 유전양식을 제시할 수가 없었다. 외부 생식기를 구성하는 각 부속기관 중 분류상 중요 기준이 되는 생식궁은 종 특이적 모양을 띠고 있었으며, 종간 접종 생식궁의 일반적인 형태는 부모종간의 중간형인 mosaic 구조였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2515-2517
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• 1998

The micro fresnel lens(MFL) was modeled and fabricated on a XY-stage electrostatically driven by comb actuator. The modeled MFL was approximated as a step shape with 4-phase and 4-zone plate. The focal length and diameter of the MFL is 20mm and 912${\mu}m$, respectively. The XY-stage suspending the MFL is designed to generate a large static displacement up to about 20${\mu}m$. On SOI substrates, we first fabricated MFL using the RIE(reactive Ion etching) technology and then patterned and etched bulk silicon to make XY-stage. After the fabrication of all structures on top side of the SOI substrates. $Si_3N_4$ was deposited for passivation of all structures using PECVD(plasma enhanced chemical vapor deposition). All the MFL systems width comb drive actuator were released by KOH etching from the bottom side of the SOI wafer using double-sided alignment technique. In fabrication of MFL, a dry etching conditions is established in order to improve surface roughness and to control the etched depth.

• Journal of Species Research
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• 제1권2호
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• pp.156-174
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• 2012

Monchenkocyclops gen. nov. was erected to accommodate M. changi sp. nov. from South Korea (type species), M. mirabdullayevi sp. nov. from Kazakhstan, M. biarticulatus (Monchenko, 1972) comb. nov. from Uzbekistan, and M. biwensis (Ishida, 2005) comb. nov. from Japan. The latter species was originally described from surface-water habitats of the ancient Lake Biwa in the genus Diacyclops Kiefer, 1927, while two Central Asian species were previously collected from groundwater habitats and assigned to the genus Acanthocyclops Kiefer, 1927. Monchenkocyclops changi is also found in subterranean waters, and described here in detail. It is morphologically most similar to its Uzbek congener (not to the Japanese one), which rises some interesting zoogeographical questions about the disjunct distribution of this genus. Range fragmentation is a more plausible explanation for this distribution pattern than range expansion, and we emphasize four lines of evidence that support this hypothesis. Four species of Monchenkocyclops share not only the same segmentation of the swimming legs, but also the exact same armature formula of all swimming legs, in addition to many other morphological characters, such as the caudal rami shape and armature, absence of exopod on the antenna, similar shape of the seminal receptacle, fifth leg, etc. They can be distinguished mostly by the relative length of different armature elements, such as the innermost terminal caudal setae, and inner setae and apical spines on the third endopodal segment of the fourth leg. A dichotomous key to species is provided.

• 센서학회지
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• 제8권5호
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• pp.368-376
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• 1999

본 논문에서는 머리빗형 액튜에이터의 제작 공정 중에서 RIE 식각 공정시 발생하는 식각의 비등방도의 변화에 의해서 머리빗형 액튜에이터의 스프링 상수, 공진 주파수, 정전 구동력 과리고 진동자 변위 등에서 발생하는 동작 특성이 설계 값으로부터 변화되는 것을 예측하였다. 이를 위해 $6\;{\mu}m$ 두께의 폴리실리콘에 대한 RIE 식각 실험을 수행하여 RF power, $Cl_2$ 유량 그리고 챔버내 압력에 따른 비등방도를 측정하였다. 실험 결과에서 RF Power, $Cl_2$ 유량, 그리고 챔버내 압력이 증가할수록 비등방도 감소하였다. 이러한 비등방도 감소에 따른 머리빗형 구조물의 동작 특성을 세 가지 다른 지지빔의 경우에 대해 예측하였는데 세 가지는 fixed-fixed, crab-leg, 그리고 double crab-leg 구조이다. 비등방도가 감소함에 따라 즉, 지지빔의 단면이 직사각형이 아니고 사다리꼴이 되면서, 머리빗형 액튜에이더의 스프링 상수, 공진 주파수, 그리고 정전 구동력은 감소하였지만 질량체의 변위는 증가하였다. 그리고 세 가지 구조물 중에서 double crab-leg 지지빔을 갖는 머리빗형 액튜에이터의 특성이 비등방도에 의해 가장 큰 영향을 받는 것으로 나타났다.