• 치과방사선
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• 제11권1호
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• pp.51-58
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• 1981

The author examined 515 full mouth roentgenograms stored in the Dept. of Oral Radiology, College of Dentistry, Seoul National University. For evaluating the efficiency of the routine full mouth roentgenogram, each of abnormal conditions such as impacted teeth, missing, caries, crown, filling and apical lesions was observed. The results obtained were as follows; 1. Among 14.420 teeth examined, missing teeth were 174, impacted 16, caries 161 and treated 1,162. 2. The incidence of impacted third molar was close to 18.7 percent and the incidence of missing third molar was about 33.4 percent. 3. Among carious and treated teeth, 178 teeth (1.2%) were needed observation of root apex. And of these teeth, 119 teeth 0.8% were observed with apical lesion. 4. There is a considerable relation between the incidence or size of apical lesion and the accuracy of endodontical treat. 5. Among the teeth with apical lesion, upper and lower first molars were most frequent (about 41%), upper and lower canine were rare (about 1.7%).

• 치과방사선
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• 제11권1호
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• pp.67-74
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• 1981

The study was performed to investigae the thickness of lamina dura of the human teeth in periodontal disease, which obtained from the intraoral roentgenograms of the 122 cases taken by bisecting technic. All films were divided into the different ages, the different sexes, and the different location of the different teeth. The obtained results were as follows: 1. Compared with the normal teeth, the thickness of lamina dura in periodontal disease is in creased in all of different ages, sexes and teeth. (equation omitted) 2. Generally, the alveolar crest portion is the thickest among the root surfaces, and midroot, apex followed, and the average thinckness of the posterior teeth is thicker than that of anterior teeth. The mean value of the whole maxillary teeth is almost same as that of mandibular teeth. On the whole cases, the differences of male and female is about 0.01㎜, which is not a significant differences.

• Journal of Plant Biology
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• 제29권2호
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• pp.129-133
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• 1986

Transections of the stem region close to the shoot apex show the occurrence of an outer, complete ring of procambium and an inner group of discrete procambial strands. From the outer ring, small, discrete vascular bundles and vascular cambium originate, while the inner group forms the discrete, medullary vascular bundles with intrafascicular cambium. Secondary thickening is essentially due to the activity of the cylinder or complete ring of vascular cambium that originates from the procambium. The medullary intrafascicular cambia also form some secondary tissues. The vascular cambium produces secondary xylem inwards and secondary phloem outwards as in the normal secondary thickening process. The distinctive feature, however, is perpetual discreteness of the medullary vascular bundles. No successive series of cambia or secondary vascular bundles are found.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권5호
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• pp.295-304
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• 2003

In this paper, we proposed a hardware-oriented Genetic Algorithm Processor(GAP) based on subpopulation architecture for high-performance convergence and reducing computation time. The proposed architecture was applied to enhancing population diversity for correspondence to premature convergence. In addition, the crossover operator selection and linear ranking subpop selection were newly employed for efficient exploration. As stochastic search space selection through linear ranking and suitable genetic operator selection with respect to the convergence state of each subpopulation was used, the elapsed time of searching optimal solution was shortened. In the experiments, the computation speed was increased by over $10\%$ compared to survival-based GA and Modified-tournament GA. Especially, increased by over $20\%$ in the multi-modal function. The proposed Subpop GA processor was implemented on FPGA device APEX EP20K600EBC652-3 of AGENT 2000 design kit.

• Restorative Dentistry and Endodontics
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• 제6권1호
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• pp.77-81
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• 1980

The author has studied comparatively the sealing quality of conventional Z.O.E. cement, Kerr sealer and Nogenol sealer by means of penetration of 2% methylene blue solution through the root apex of human teeth in 72 cases as time elapsed. The results were as follows; 1. All the specimens, whose dye immersion time is two days, showed dye penetration of low degree unrelated to the kinds of root canal sealer. 2. Kerr sealer group, like conventional Z.O.E. group, showed dye penetration of high degree related to increased time of immersion in the dye. 3. In Nogenol group, there was slight increase in penetration related to increased time of immersion in the dye. 4. Kerr sealer group showed comparatively lower grade of dye penetration than conventional Z.O.E. and higher than Nogenel sealer.

• Restorative Dentistry and Endodontics
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• 제7권1호
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• pp.139-144
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• 1981

Eighty four human maxillary first premolars were injected with china ink, decalcified, cleared and used in study, in vitro, to determine the number of root canals, the frequency and location of lateral canals, the frequency and location of transverse anastomoses, the curvature of root canals, the location of apical foramens, and the frequency of apical deltas. The results were as follows: 1. Most of the teeth demonstrated two canals, but 20.2% of the teeth were found to have one canal. 2. Of the 151 canals studied, 38.4% of the canals were found to have lateral canals and these ramifications were usually located in the apical third of the root. 3. Of the two root canals in one root, 35.7% of the canals were found to have transverse anastomoses and were usually located in the middle third of the root. 4. 15.2% of apical foramens were located directly on the root apex and 84.8% of them laterally, and 52.3% of canals showed distal curvature.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.101-102
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• 2012

수중에서는 대기와 달리 매질의 차이로 인하여 통신의 제약이 따르므로 초음파를 이용하여 정보를 송 수신한다. 수중통신을 하기 위해서는 신호를 증폭시키는 전력증폭기와 증폭된 전기 신호를 초음파로 변환시키는 트랜스듀서가 필요하다. 전력증폭기는 선형적인 출력이 보장되어야 하며, 수중에서의 발열과 연료문제로 인하여 높은 효율로 동작하여야 한다. 하지만 기존의 전력증폭기는 인가되는 고정전압과 출력전압의 차이로 인해 손실이 발생하여 효율이 저하된다. 본 논문에서는 수중 통신에 적합한 특성을 가진 APEX사의 Class B push-pull 타입의 MP108A증폭기를 사용하여 선형적인 출력 특성을 보장하며 넓은 대역폭을 갖는 전력증폭기를 구현하고, 실험을 통해 특성을 확인하였다.

• Journal of Species Research
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• 제2권1호
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• pp.69-77
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• 2013

One newly recorded species, Dryopteris namegatae, sect. Hirtipedes, was collected in forests in Jeju-do. Dryopteris namegatae (vernacular name: 'Tam-ra-top-ji-ne-go-sa-ri') was distinguished from other Korean congeners of sect. Hirtipedes of the genus Dryopteris by having stiff black scales on stipe and rachis, less narrowed base of lamina, and adaxial surface of pinna immersed along veins. Dryopteris hangchowensis ('Gak-si-top-ji-ne-go-sa-ri', new local name), recorded without any comments and description, was reexamined with similar taxa and was distinguished by smaller plants, brilliant leaves, many prominent fimbriate blackish scales on stipe and rachis, long-pointed apex of lamina and pinna, halfway-lobed pinna, and narrowest pinna. Descriptions and illustrations of the two species and their photographs in the habitat are provided along with a key to the species of sect. Hirtipedes of Dryopteris in Korea.

• Journal of the Optical Society of Korea
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• 제4권1호
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• pp.1-6
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• 2000

Adaptive optics(AO) removes or compensates the distortion caused by a turbulent atmosphere or medium. A wavefront sensormeasures the distortion, on which the correction of AO is based. A new idea of pupil plane wavefront sensing, which consists of a relay lens and a pyramidal-shaped prism, was previously proposed. This paper reviews the idea of pupil wavefrontsensing and presents prism, was previously proposed. The simulation shows that pupilwavefront sensing provides full wavefront sensing when the intensity peak of PSF is located within half of the Airy radius from the apex of the sensor. Adding to this, the sensor is shown to have optimum sensor output with a finite bevel size of the pyramidal prism.

• Animal Systematics, Evolution and Diversity
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• 제34권2호
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• pp.69-78
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• 2018

We reviewed five South Korean species belonging to the genera Clistopyga Gravenhorst, 1829 and Endromopoda $Hell{\acute{e}}n$, 1939, which are recorded for the first time from South Korea: Clistopyga incitator (Fabricius, 1793), Clistopyga sziladyi Kiss, 1959, Endromopoda arundinator (Fabricius, 1804), Endromopoda detrita (Holmgren, 1860), and Endromopoda phragmitidis (Perkins, 1957). The genus Clistopyga can be distinguished from the congeneric species by distinctly upcurved ovipositor, with enlarged hypopygium, and Endromopoda by apical perpendicular teeth of ovipositor on apex. Diagnoses, illustrations and keys to South Korean species of the genera Clistopyga and Endromopoda are provided.