• Journal of the Korean Society for Nondestructive Testing
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• v.24 no.2
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• pp.136-141
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• 2004

A torsional guided wave mode was applied to detect a crack in a pipe. An array of electromagnetic acoustic transduce. (EMAT that can generate and receive torsional guided ultrasound with the frequency of 200kHz was designed and fabricated for testing a pipe of 2.5 inch diameter Artificial notches with various depths were fabricated in a bent feeder pipe mock-up and the detectability was examined from the distance of 2m of the specimen. The axial notches with the depth of 5% of wall thickness were successfully detected by a torsional mode (T(0,1)) generated by the EMAT However, it was found that the depth of defects was not related to the signal amplitude.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.7
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• pp.806-813
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• 2014

The EGR system being reburned the part of the exhaust gas through intake system indicates more favorable emission characteristics to reduce NOx in a gasoline engine, but the case of inappropriate exhaust gas quantity induced from engine is fallen engine power caused by unstable combustion. In this study, we examined a method to predict EGR ratio according to various engine operation condition based by intake manifold pressure and confirmed such a prediction data through an experimental method. And after having constituted feedback EGR control algorithm in a base with such a prediction data, we acquired qualitatively similar results by having compared data provided through an EGR feedback control experiment with the data which calculated quantity of residual gas for the engine operation condition. Therefore, the applied algorithm and the system for feedback EGR control showed feasibility applied to real electronic control EGR technology.

• Applied Microscopy
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• v.31 no.4
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• pp.375-383
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• 2001

To understand the fine structure of Korean bat livers , the authors investigated the liver of four Korean bats; Rhinolephus ferrumequinum korai, Myotis macrodactylus, Myotis dauhentonii ussrinesis, and Murina leucogaster intermedia by transmission electron microscopy. The hepatocytes of Rhinolophus ferrumequinum korai had large-sized mitochondria and many peroxisomes. In the Myotis macrodactylus, juctional completes, especially desmosomes, were well developed. The Myotis daubentonii ussrinesis had many glycogen particles in the cytoplasm. Also, the space of Disse and sinusoidal spare was filled with amorphous materials. In the Murina leucogaster intemedia, basement membrane was prominent in the sinusoid, and no Kupffer and Ito cells were observed These results suggest the characteristic differences in the liver ultrastructure among Korean bats.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.7 no.3
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• pp.99-104
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• 2012

The purpose of this study is to develop an educational program for improving conversational skills in military counselors and prove its effects. For statistical analysis, t test to find out homogeneity between the experimental and control group and to find out the differences of two groups, and an evaluation before and after the program to verify the therapeutic effects of the program were each proved by SPSS 15.0 for Windows. The followings are the list of the results. First of all, the program was effective in improving military counseling communication skills. Secondly, it was proved to be effective in improving self-effectiveness in counselors. Thirdly, the program was effective in improving interpersonal communication skills. Fourthly, the program revealed its therapeutic effects. Therefore, it is concluded that the program would help greatly in military counseling and living.

• Applied Biological Chemistry
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• v.8
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• pp.81-86
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• 1967

Changes in the protein contents of various organs of the germinating soy bean as well as the effect of X-irradiation on the RNA content of cotyledon of it were investigated. 1) The protein content of germinating organs other than cotyledon increase while that of cotyledon decreases as germination proceeds, which is indicative of the fact that the former organs are anabolic and the latter catabolic in nature with regard to their protein metabolism during germination. 2) The cotyledon RNA content of soybean decreases until the 6 th day after germination initiated, and increases thereafter . When the seeds are exposed to $300{\gamma}$ X-irradiation, these tendencies seem to be accelerated, but when exposed to $600{\gamma}$ and $900{\gamma}$ X-irradiation the decrement of RNA in the early stage is prominent and the synthetic recovery in the later period is inhibited markedly due to radiation damage rather than radiation activation.

• Journal of the Korean Wood Science and Technology
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• v.24 no.2
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• pp.61-70
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• 1996

침엽수재(針葉樹材)(Radiata pine, Pinus radiata)MDF와 활엽수재(闊葉樹材)(Rubber wood, Hevea brasiliensis)MDF 각 1종을 대상으로 MDF를 제조하기 전 원료(原料) 섬유(纖維)의 미세(微細) 구조(構造) 및 내부결합력 시험 후 MDF의 파괴면(破壞面)에서 섬유표면(纖維表面)에 접착제(接着劑)가 도포(塗布)된 형태를 주사전자현미경(走査電子顯微鏡)으로 관찰하였다. 원료 섬유는 침(針) 활엽수재(闊葉樹材) 모두 fiber twisting 및 shrinkage fold 등이 관찰되었다. 침엽수재(針葉樹材)의 경우는 유연벽공부(有緣壁孔部)에서 유연벽공(有緣壁孔)이 없는 부분에 비하여 shrinkage fold의 발생 빈도가 낮고 표면(表面) 박리(剝離)는 가도관(假導管) 중 벽공이 없는 부분에서 관찰되었다. 활엽수재(闊葉樹材) 목섬유(木纖維)는 침엽수재(針葉樹材)와 마찬가지로 shrinkage fold가 관찰되었으나 표면(表面) 박리(剝離)는 거의 관찰되지 않았다. 활엽수(闊葉樹) 섬유(纖維)에서는 벽공의 유무에 따른 shrinkage fold의 차이(差異)가 거의 관찰되지 않았는데 이는 목섬유(木纖維)가 침엽수(針葉樹) 가도관(假導管)보다 작은 단벽공(單壁孔)을 갖기 때문으로 생각된다. 또 방사유세포(放射柔細胞)와 가도관(假導管) 및 목섬유(木纖維)의 박리(剝離) 부분(部分)에는 융기부(隆起部)가 관찰되었다. 내부결합력 시험후 나타난 파괴면을 통하여 접착제 분포를 관찰한 결과 거의 모든 섬유(纖維)들이 접착제(接着劑)로 둘러싸여 있었으며 섬유(纖維)간 접착형태(接着形態)도 매우 다양하였다. 침활엽수재(針闊葉樹材)간에 강도(强度)의 차이는 있었지만 파괴(破壞) 형태(形態)는 큰 차이를 나타내지 않았다. 즉 침활엽수(針闊葉樹) 모두 접착층(接着層)이 아닌 섬유(纖維)에서 파괴(破壞)가 발생하였으며 섬유에서 박리(剝離)된, 세포벽(細胞壁)의 일부가 다른 섬유(纖維)의 표면(表面)에 남아있는 형태와 섬유(纖維) 표면(表面)에서 떨어져 나간 형태로 관찰되었다. 세포 구성이 단순한 침엽수(針葉樹) MDF에 비하여 유세포(柔細胞)와 도관(導管) 및 목섬유(木纖維)의 파편들이 활엽수(闊葉樹) MDF에서는 다양(多樣)하게 분포하였다.

• The Korean Journal of Zoology
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• v.33 no.3
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• pp.354-364
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• 1990

The ultrastructure and silk formational process of the flagelliform glands, one of the capture thread producing organs in the orb web spider (Nephila clavata L. Koch), have been studied with electron microscope. A pair of flagelliform glands consist of three distinct regions: excretory duct, storage sac and convoluted tail. This gland is connected to the large spinning tube (spigot) of the posterior spinnerets with two pairs of aggregate glands, and showed a characteristic spigot structure called "triad". The excretory duct consists of three long segments surrounded by the same sheath of connective tissue. The distal duct near the spinning tube bears the electron lucent subcuticles which have the functions of water removal and orientation of the silk fiber, whereas the proximal duct near the sac contains the cuticule precursor transported through the intercellular space. Cytoplasms of the sac and tail regions have well developed rough endoplasmic reticulum and contain the round secretory granules commonly, but the electron densities and internal textures of the granules do not coincided. Adjacent epithelial cells are connected with the specialized septate junctions, and secretory granules accumulated at the apical pole are released to the lumen by the apocrine secretion.secretion.

• Nuclear Engineering and Technology
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• v.21 no.1
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• pp.40-47
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• 1989

For the effective design of a beam forming structure of the negative-ion-based neutral beam injector, a computer program based on a particle simulation model is developed for the calculation of charged particle motions in the electrostatic fields. The motions of negative ions inside the acceleration tube of a multiple-aperture triode are computed at finite time steps. The electrostatic potentials are obtained from the Poisson's equation by the finite difference method. The successive overrelaxation method is used to solve the matrix equation. The particle and force weighting methods are used on a cloud-in-cell model. The optimum design of the beam forming structure has been studied by using this computer code for the various conditions of elctrodes. The effects of the acceleration-deceleration gap distance, the thickness of the deceleration electrode and the shape of the acceleration electrode on beam trajectories are exmined to find the minimum beam divergence. Some numerical illustrations are presented for the particle movements at finite time steps in the beam forming tubes. It is found in this particle simulation modelling that the shape of the acceleration electrode is the most significant factor of beam divergence.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.1
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• pp.12-20
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• 2021

The purpose of this retrospective study was to evaluate the survival rate by comparing Class II restoration using flowable resin composite with stainless steel crown in primary molars. Electronic medical records and radiographs of 1,504 primary molars with proximal caries of 590 patients from June 2015 to August 2019 were analyzed. With the collected data, survival analysis was performed using the Kaplan-Meier method. The 1-year survival rate of flowable resin composite in the primary molar was 98.5%, 3-year survival rate was 87.7%, and mean survival time was 39 months. There was no statistically significant difference between flowable resin composite and stainless steel crown (p = 0.896). Within the limits of this study, Class II restoration using flowable resin composite can be considered a promising option for the treatment of proximal caries in primary molars.

• Journal of Korean Society of Archives and Records Management
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• v.24 no.2
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• pp.113-137
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• 2024

In this study, considering the National Memorial of the Korean Provisional Government as a "Larchiveum," the researchers attempted to develop a classification system that can comprehensively categorize various types of materials and propose a method of providing an online service. To this end, as a case study, the researchers examined the classification system structure and contents of the National Archives of Korea, National Assembly Archives, and Archives of Korean History of the National Institute of Korean History, which are the current material collection institutions of the Korean Provisional Government. Regarding online services, apart from the three institutions above, the Imperial War Museum and the Hoover Institution at Stanford University were also explored. Through the implications derived from the case analysis of domestic and foreign institutions, a basic hierarchical classification system by provenance for the materials held by the institution was established, and a multi-classification system was presented according to the classification criteria of "by type, by era, and by subject." In addition, methods of applying the developed classification system to online services were proposed.