• Journal of Institute of Control, Robotics and Systems
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• v.6 no.1
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• pp.8-14
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• 2000

In this paper, three adaptive sliding mode control algorithms, which self-tune both the sliding mode gain and the boundary layer thickness, are proposed. The first algorithm uses a gain adaptation rule is combined with the boundary layer thickness adaptatioin rule to satisfy the sliding condition. In the third algorithm, the computation burden of the second algorithm is reduced further, and therefore no extra cost is required for real-time implementation. Due to the mixed sliding mode gain and the boundary layer thickness adaptation scheme, the tracking error and the chattering of the control input can be reduced greatly.

• Journal of Ocean Engineering and Technology
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• v.11 no.3
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• pp.180-190
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• 1997

잠수함이 저심도 조건에서 특수임무 수행시, 표면파도 및 조류등 외란의 영향하에서 요구심도 및 위치 유지를 위한 강인한 자동항법장치 설계는, 첨단 군용 잠수함 개발에 필수적이다. 본 연구는 잠수함 조종 운동역학계에 기초하여, 정확한 심도 및 피치 운동 제어를 위해 선형 행렬 부등식을 이용한 혼합 $H_2/H_{\infty}$ 설계법을 사용, 다중 목적 함수로 표현된 잠수함의 조종성능들을 개선하였다. 또한, 제어기 설계법의 타당성을 수치 시뮬레이션을 통하여 검증하였다. 결과적으로 본 제어법은 각종 외란 및 계의 불확실성하에서 잠수정의 만족스러운 과도 상태 응답과 일정 심도 유지 및 피치 각도 변동 최소화에 적합한 강인한 방법임이 검증되었다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.493-494
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• 2006

Chip breaker of cutting tool is an important feature to enhance cutting performance. Powder injection molding process was used to produce a triangular-shape cermet grooving insert which has three chip breakers. Attrition milled cermet powders were mixed with wax-based binder system in continuous twin screw extruder. Three-plate injection mold with slide cores was used to produce injection-molded parts. After molding, solvent and thermal debinding was carried out. Sintering was conducted in a batch furnace with a graphite heater. The sintered parts satisfy the requirements of dimensional tolerances and material properties.

• Bulletin of the Korean Chemical Society
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• v.15 no.5
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• pp.399-404
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• 1994

The non-Newtonian viscosities (the specific or intrinsic viscosities) of poly(L-proline) (PLP, $M_v$=19,000 and 32,000) in various mixed-solvent systems like water-propanol and acetic acid-propanol of varying compositions were measured during the reverse mutarotation (Form II ${\rightarrow}$Form I) by the application of external pressure (up to 4.5 psi). The non-Newtonian viscosity effect was found to be larger in acetic acid-propanol system than in water-propanol system and to somewhat decrease during the reverse mutarotation at a given solvent system. The non-Newtonian viscosity behavior of PLP in aqueous salt ($CaCl_2$) solution was also studied, from which it was found that the degree of the non-Newtonian effect decreased with increasing salt concentration, and increased with increasing PLP molecular weight. These findings could be explained in terms of conformational changes of PLP in solution (like the helix-helix or helix-coil transition) involved.

• Korean Journal of Veterinary Research
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• v.61 no.1
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• pp.3.1-3.5
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• 2021

A 12-year-old, castrated male, mixed dog presented with a history of gradual abdominal distention for a year and anorexia recently, with abdominal radiographs showing a gastric pylorus distention. A solitary, pedunculated, heterogeneous mass arising from the mucosal layer in the pylorus with intact wall layers was identified during ultrasound and computed tomography. The gastric muscular layer was evenly thick. After surgical excision of the mass, histological examination confirmed hypertrophic pyloric gastropathy with polypoid growth and Helicobacter spp. infiltrating the gastric mucosal epithelium. This is the first reported diagnostic imaging case of hypertrophic pyloric gastropathy with Helicobacter spp. in a dog.

• Journal of the Korean Geotechnical Society
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• v.31 no.1
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• pp.5-14
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• 2015

Seabed may undergo large excess pore water pressure in the case of long duration of high wave loading. This excess pore water pressure may reduce effective stress and, consequently, the seabed may liquefy. Thus, it is necessary to develop a numerical technique which can precisely evaluate the dynamic response of seabed due to wave action. In this study, a new numerical technique named mixed model (2D NIT & FLIP models) was proposed. The dynamic wave pressure and water flow velocity acting on the boundary between seabed and the wave field was estimated using 2D-NIT model. This result was used as input data in FLIP program for investigation of dynamic response of seabed. To secure the reliability of the mixed model, the numerical analysis results of the mixed model were compared with Yamamoto's solution and Chang's experiment results. The comparison results indicated that there were some differences between them, but the general trend of the effective stress increment and the excess pore water pressure along the depth of seabed was similar to each other. Thus, this study clearly supports the plausibility of the numerical analysis of the mixed model.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.1
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• pp.1-6
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• 2010

CuInGaSe(CIGS) mixed-source was prepared by hydride vapor phase epitaxy (HVPE). Each metal was mixed in regular ratio and soaked at $1090^{\circ}C$ for 90 minutes in nitrogen atmosphere. After making the mixed-source to powder state, the pellet was made by the powder. The diameter of pellet is 10 mm. The CIGS thin film was deposited on soda lime glass evaporated Mo layer bye-beam evaporator. To confirm the crystallization, we measured X-ray diffraction (XRD). High intensity X-ray peaks diffracted from (112), (204)/(220), (116)/(312) and (400) of CIGS thin film and from (110) of Mo were confirmed by XRD measurement.

• Journal of the Korean Society of Costume
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• v.56 no.7 s.107
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• pp.1-17
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• 2006

This study purposed to examine Korean people's white clothes custom historically and to explain the aesthetic consciousness latent in the custom. Korean people preferred white clothes, even up to foreigners called them White-clad folk. Not only as in old historical literatures, but also in Soo-suh, Shin-Dang-suh including Sam-Kuk-Ji in China, white clothes were a real symbol to Korean people, ranging chronically far back to the age of ancient tribal countries, Sam-Kuk Period through Koryo Dynasty and even to modern age near the end of Chosun Dynasty, wearing with pleasure regardless of age, sex or social position. Even King himself in Koryo Dynasty is said to have worn white clothes when he was out of official hours. During the Koryo and Chosun Dynasty, white clothes were sometimes prohibited for various reasons including conflicts with the theories of yin-yang and the five elements but such regulations were not effective. To Korean people, white clothes were ordinary people's everyday dress as well as noble people's plain suits, saints' uniforms with religious meanings, ceremonial costumes, funeral garments, etc. The various uses show that white clothes have been worn by many people. The unique custom that a People have worn white clothes consistently for such a long time may contain very deep symbolic meanings representing the people's sentiments and spirits. The present study understood that the meanings come from religious sacredness, magical wish for brightness, the pursuit of purity originating from the people's national traits, assimilation with nature and the will to attain whole ascetic personality. Aesthetic attitudes based on aesthetic values summed up as sacredness, brightness, purity, assimilation with nature, asceticism, etc. are the aesthetic consciousness pursued by Koreans through their white clothes. For Koreans, white color is the origin of their color sense coming from primitive religions such as worshipping the sun and the heaven. In this way, Korean people's preference for white clothes began with primitive religions, was mixed with various social, cultural and religious influences and finally was settled as their durable spirit, symbol and beauty.

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.159-163
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• 2002

A single phase perovskite relaxor ferroelectric PMN-PT-BT was prepared by a single calcination and the modified mixed oxide process. It was accomplished by ball-milling PbO, $Nb_2O_5,\;Ti(OC_3H_7)_4,\;BaCO_3,\;and\;Mg(NO_3)_2$ instead of MgO, removing the solvent, and then followed by calcination at 900$^{\circ}C$ for 2h. The specimen sintered at 1100$^{\circ}C$/2h showed the sintered density of 7.83 g/$cm^3$, room temperature dielectric constant of 22000, and dielectric loss of 2.5%. Addition of 1.0 mole% (0.3 wt%) of Ag as $AgNO_3$ and followed by calcination at 550$^{\circ}C$/2h lowered the sintering temperature to 900$^{\circ}C$. It still showed the sintered density of 7.88 g/$cm^3$, room temperature dielectric constant of 20000 and dielectric loss of 2.4%.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.6
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• pp.275-281
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• 2017

AlN is a promising material for wide band gap and high-frequency electronics device due to its wide bandgap and high thermal conductivity. AlN has advantages as materials for power semiconductors with a larger breakdown field, and a smaller specific on-resistance at high voltage. The growth of a p-type AlN epilayer with high conductivity is important for a manufacturing an AlN-based applications. In this paper, Mg doped AlN epilayers were grown by a mixed-source HVPE. Al and Mg mixture were used as source materials for the growth of Mg-doped AlN epilayers. Mg concentration in the AlN was controlled by modulating the quantity of Mg source in the mixed-source. Surface morphology and crystalline structure of AlN epilayers with different Mg concentrations were characterized by FE-SEM and HR-XRD. XPS spectra of the Mg-doped AlN epilayers demonstrated that Mg was doped successfully into the AlN epilayer by the mixed-source HVPE.