• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.11
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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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• v.5C no.6
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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.

• Transactions of the Society of Information Storage Systems
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• v.10 no.1
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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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• v.37 no.1
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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.

• Korean journal of applied entomology
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• v.35 no.3
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• pp.216-220
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• 1996

Drosophila simulans and D. mauritiana are sibling species, the former cosmopolitan and the latter restricted to the oceanic island of Mauritius. Sex comb-tooth number of male flies of D. simulans were about 9.83, while those of D. mauritiana were 12.90. Genital arch of D. simulans is large semicircular shaped expasion, while that of D. mauritiana is a narrow fingerlike expansion. We used classical genetic analysis to measure effects of genes on the X chromosome responsible for numeral and morphological differences in sex comb-tooth and genital arch between these species, respectively. For these purposes, mutant strain of D. simulans and wild type strain of D. mauritiana were hybridized and males of the FI and the backcrossed progenies were compared with two characters above mentioned. The sex comb-tooth number of F, males were about 11.79, and the genitalia of F, male were intermediate in shape between those of D. simulans and D. mauritiana. Genetic analysis of sex comb-tooth number and genital arches differing between D. simulans and D. mauritiana showed that very little diffemce was due to effect of the X chromosome.

• Korean journal of applied entomology
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• v.34 no.4
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• pp.308-313
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• 1995

Drosophila melanogaster, D. simulans, and D. sechellia are closely related species which belong to the D. melanogaster complex; the first two cosmopolita and the last one restricted to th Seychelles archipelago. The phenogenetical relationship between this complex and their hybrids were investigated by the comparison of sex-comb tooth number an genital arch of male. In interspecific hybrids of all crosses between three species four hybrid males were produced and completely sterile. Males of D. simulans (${O}_{9}$) have significantly less sex-comb teeth (mean 8.35) than either D. melanogaster (OR, mean 10.73) and D. sechellia (Ja, mean 10.60). From the analysis by the number of sex-comb tooth in interspecific hybrids we could not represent the direction of heredity nature. each species of D. melanogaster complex were characteristic in the shape of the genital arch, which readily allows these species to be distinguished. The common structure of the genital arch in the interspecific hybrids were mosaic-like structure between parental species.

• Proceedings of the KIEE Conference
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• 1998.07g
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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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• v.1 no.2
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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.

• Journal of Sensor Science and Technology
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• v.8 no.5
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• pp.368-376
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• 1999

This paper predicts the changes in the spring constant, the resonant frequency, the electrostatic force, and the displacement of a resonant structure due to non-ideal anisotropic RIE etching process. First, a $6\;{\mu}m$ thick polysilicon was etched by RIE and the anisotropy of the etched structure was measured as a function of a RF power, a $Cl_2$ flow rate and a chamber pressure. In the experimental results, an anisotropy was decreased as the RF power, the $Cl_2$ flow rate, or the chamber pressure was increased. A comb actuator's operation characteristic was predicted depending on the anisotropy variations in RIE etching. Comb actuators with three different support beam structures were investigated : fixed-fixed, crab-leg, and double crab-leg. As the RIE etch anisotropy becomes non-ideal, i.e. the cross section becomes rather a trapezoidal than a rectangular shape, it decreases spring constant, resonant frequency and electrostatic force of a comb actuator but it increases the displacement of the mass. Among the three structures, the comb actuator with double crab-leg support beams is more influenced by anisotropy variation in RIE etch than other two.