• 대한치과기공학회지
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• 제23권1호
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• pp.55-64
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• 2001

This study is focusing on the improvement of problems of Ti-6Al-4V alloy. A new Ti based alloy, Ti-15Sn-4Nb, have designed to examine any possibility of improving the mechanical properties and biocompatibility. Specimens of Ti alloys were melted in vacuum arc furnace and homogenized at $100^{\circ}C$ for 24h. All specimens were solution treated at $812^{\circ}C$ and aged at $500^{\circ}C$ for 10h. The corrosion resistance of Ti alloys was evaluated by potentiodynamic polarization test and immersion test inl%Lactic acid solutions. Ti-15Sn-4Nb system alloys showed Widmanstatten microstructure after solution treatment which is typical microstructure of ${\alpha}+{\beta}$ type Ti alloys. Analysing the corrosion resistance of Ti alloys, it was concluded that the passive films of Ti-15Sn-4Nb system alloys are more stable than that of Ti-6Al-4V alloys. Also, the corrosion resistance of Ti-15Sn-4Nb system alloys was improved with adding elements, Hf. It was analysed that the passive film of the Ti-15Sn-4Nb alloy which was formed in air atmosphere was consisted of TiO2, SnO and NbO through X-ray photoelectron spectroscopy(XPS) analysis.

• 동의신경정신과학회지
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• 제29권3호
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• pp.121-134
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• 2018

Objectives: The purpose of this in vivo study is to observe anti-amnesic effects of Yeongkyekamjotanggayonggolmoryo (YGYM), a novel mixed herbal prescription, Ossis Mastodi and Ostreae Testa added Yeongkyekamjo-tang, on scopolamine induced amnesia in C57BL/6 mice through acetylcholine (ACh) and acetylcholinesterase (AChE) activity, Choline acetyltransferase (ChAT) mRNA expression, and antioxidant effects. Methods: Six groups, total 20 intact or 100 Sco treated mice were used in this study after one week of acclimatization period. Half the animals were used for passive avoidance task tests and hippocampus ACh content, AChE activity, and ChAT mRNA expression were measured. The other half was subjected to an underwater maze test and then the cerebral cortex antioxidant defense system was measured. Results: In the passive avoidance experiment, there was significant decrease in residence time in the bright room and in the underwater maze test, escape latency to escape from the esophagus significantly increased compared with the normal control group. At the final sacrifice, ACh content and ChAT mRNA expression decreased, AChE activity increased, and cerebral cortical MDA increased GSH content, SOD and CAT activity in Sco control mice, as compared to intact vehicle control mice. However, these Sco treatment-related memory loss through AChE activation destroyed the cerebral cortex antioxidant defense system, and was inhibited dose-dependently by 28 days consecutive oral pretreatments of YGYM extracts 500, 250, 125 mg/kg. Conclusions: In the above results, YGYM extract that oral administration of YGYM extracts alleviates the antioxidant defense system, through preservation of ACh mediated by upregulation of ChAT mRNA expression, and increase of AChE inhibition and brain antioxidant defense systems.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.103.6-103
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• 2001

Glaucoma is an eye disease which is caused by abnormal high IOP (Intra Ocular Pressure) in the eye. High IOP is caused by the aqueous humor which is produced consistently but not drained due to the malfunction of the trabecular system which has a role of draining the aqueous humor into the venous system. Currently, there are some methods to treat glaucoma, Among these, the use of implants is increasing in these days due to many problems in other methods. However, conventional implants are passive implants and have critical disadvantage. Therefore, it is needed to develop a new implant using MEMS structure which is capable of controlling the IOP actively and copes with personal difference of patients. An active glaucoma implant consists of the valve actuator, pressure sensor, controller, and power supply. In this paper the valve actuator is considered. We make experiments and simulations with the fabricated ...

• Asian-Australasian Journal of Animal Sciences
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• 제14권8호
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• pp.1157-1163
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• 2001

First-litter gilts were used to determine how different dietary treatments during gestation affect the reproductive performance of gilts and immunity development of their piglets. Twenty-two crossbred $Landrace{\times}Yorkshire$ gilts were randomly assigned to three dietary treatments, Following conception, the gilts were fed experimental diets until farrowing occurred. The diet for treatment I was low protein diet (8% CP), treatment 2 had an additional supplement of 0.14% threonine that was added to the low protein diet, and treatment 3 was a control diet containing 12% CP. During gestation, net body weight gain of sows in treatment group 2 was higher than in treatment group 1 (p=0,075), However, during lactation there was no difference between all treatments groups on body weight loss and their live piglets at birth. Although milk IgG between treatments did not differ, treatment groups 2 and 3 were slightly higher than treatment group I was, Plasma IgG concentrations in piglets were however equal within all treatment groups at birth and at 7 days of age, at 21 days of age, it was higher in treatment group I than it was in the other two groups (p<0.01), Threonine supplementation to a low protein diet during gestation slightly increases milk IgG of sows, It is beneficial for piglets to acquire more passive immunity, but a suppressive effect was also noted on the endogenous IgG synthesis in piglets. A gestation diet of 8% CP for gilts can stimulate immuno-system of her piglets.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권2호
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• pp.9-18
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• 2003

폐탄광에 의한 주변 지하수의 오염원과 오염 경로의 파악을 위해 강원도 평창군 소재 한창탄광을 대상으로 계절 변화에 따라 SAPS(Successive Alkalinity Producing System)를 이용한 자연정화 처리시설 공정의 각 단계와 폐석침출수, 탄광부근 샘물시료가 채수 및 분석되었다. 또한 지하수의 오염원 규명과 SAPS조에서의 황산염 환원 발생여부를 확인하고자 황동위원소 분석이 실시되었다. 연구지역의 지하수에서 계절적인 변화와 관계없이 높은 수소이온농도와 금속농도가 나타나는 것은 산성광산배수가 계절과 무관하게 지속적으로 지하수를 오염시킬 수 있음을 나타내고 있다고 할 수 있다. 처리시설은 산도(acidity) 제거량이 평균 18.17 g/$\textrm{m}^2$/day이고 가장 오염부하량이 많았던 9월에는 59.02 g/$\textrm{m}^2$/day 이며, 금속제거능은 거의 100%에 이르러 다른 지역의 처리시설에 비해 높은 정화성능을 갖는다. 그러나 처리시설의 각 공정 단계별로는 황 함량의 감소가 나타나지 않았고 황동위원소 조성의 변화도 거의 없었는데 이는 황산염환원박테리아에 의한 황산염환원 작용은 매우 미약하거나 전혀 이루어지지 않는 것으로 보인다 화학조성과 황동위원소 조성을 통해 샘물은 폐석침출수에 의해, 처리시설내 석축침출수는 폐석침출수와 갱구유출수에 의해 영향을 받은 것으로 판단되었다. 본 연구지역은 갱구유출수에 대한 처리시설이 가동중에 있으나 폐석침출수에 대한 대책은 없는데 이는 다른 폐광지역에서도 유사한 상황이므로 폐석침출수에 대한 오염방지 대책 마련이 시급한 것으로 사료된다.

• 대한한의학회지
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• 제20권2호
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• pp.3-11
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• 1999

The Korean system of health and medical care has been organized with both Oriental and Western medical sciences. To get complete clinical treatment results is not possible with only one-sided medical care, therefore we need to formulate an interdisciplinary plan for better health care, that is to say our ultimate purpose is the cooperative medical care for the promotion of social welfare and health. Hereupon, I made a searching inquiry into the present condition of cooperative medical care and its problems and also took a consideration into the medical state of other countries like China. Japan and North Korea where the Oriental medical care is used. The results of this investigation are as follows. There are some problems in both Oriental and Western(general) medical care, such as a lack of mutual confidence, a severance of interdisciplinary study, a shortage of professional human resources and so on. There also used to be problems of the system such as, the responsibility of medical care, the double charge for medical treatment, the governmental passive participation and policy, the private-oriented study system and so on. The solutions of these problems are that the mutual understanding and coexistence between both Oriental and Western medical sciences should be preceded and the interdisciplinary study, identified terminology and cooperative medical specialists would be necessary. Furthermore, the government has to seek some policies and legislation for the cooperative medical system and needs to support the public research institutes and centers of the cooperative medical care. After all, we have to train the cooperative medical specialists for the mutual aid of both Oriental and Western medical sciences and the government also has to support it with some policies and legislation for the better medical care system.

• 보건교육건강증진학회지
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• 제14권1호
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• pp.1-9
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• 1997

The health education in hospitals has many problems including lack of the division specialized in health education, lack of implementation system of health education, insufficient professional health education and insufficient health education materials. Despite these restraints, hospitals should reinforce health education program as a part of active response centered on disease prevention and health promotion targeting healthy people who have potential health risk before the onset of disease, rather than passive approach emphasizing the treatment. Accordingly, health education team should be organized in a hospital, in which health educators can provide the following education services. First of all, hospitals themselves should provide active community services in collaboration with community organizations. In addition, multi-disciplinary approach in cooperation with schools, work places should be reinforced to establish the comprehensive health education system. The establishment of medical service referral system with other medical institutions and the linkage system for medical information exchange are also needed. The utilization of education materials obtained through these system should be open to community residents as well as patients. Finally, medical staff working in hospitals should try to provide the high-quality health education that is as high as the level of medical services. The high-quality health education is possible when its level is based on one required by community residents and the county rather than the international or arbitrary standard.

• Steel and Composite Structures
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• 제31권4호
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• pp.387-396
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• 2019

This paper deals with the effect of ply orientation and control gain on tip transverse displacement of functionally graded beam layer for both active constrained layer damping (ACLD) and passive constrained layer damping (PCLD) system. The functionally graded beam is taken as host beam with a bonded viscoelastic layer in ACLD beam system. Piezoelectric fiber reinforced composite (PFRC) laminate is a constraining layer which acts as actuator through the velocity feedback control system. A finite element model has been developed to study actuation of the smart beam system. Fractional order derivative constitutive model is used for the viscoelastic constitutive equation. The control voltage required for ACLD treatment for various symmetric ply stacking sequences is highest in case of longitudinal orientation of fibers of PFRC laminate over other ply stacking sequences. Performance of symmetric and anti-symmetric ply laminates on damping characteristics has been investigated for smart beam system using time and frequency response plots. Symmetric and anti-symmetric ply laminates significantly reduce the amplitude of the vibration over the longitudinal orientation of fibers of PFRC laminate. The analysis reveals that the PFRC laminate can be used effectively for developing very light weight smart structures.

• 자원환경지질
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• 제53권6호
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• pp.695-701
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• 2020

본 연구는 중성의 pH 조건에서 Fe, Mn, As이 포함된 복합오염수를 배출하는 광산배수의 수질특성을 모니터링하였다. 침출수를 처리하기 위해 모래와 석회석으로 이루어진 수직흐름반응조(VFR, Vertical Flow Reactor)와 제강슬래그와 석회석을 적용한 반응조(ZMR)로 구성된 현장파일럿 장치를 설치하여 약 6개월간 운영하였다. 광산배수 내 존재하는 Fe, Mn, As에 대한 현장파일럿 장치의 처리효율을 평가하였다. 중성의 알칼리 수질특성을 가진 D광산 침출수에 VFR와 ZMR 공정을 적용한 결과, pH와 알칼리도가 효과적으로 상승하여 Fe과 As가 99%이상 제거되었으며 Mn은 98%이상 제거하여 복합오염물질 처리가 가능함을 확인하였다. 본 연구결과를 통해 Fe, As, Mn이 포함된 소규모 광산배수에 자연정화기반의 공법이 적용가능함을 확인하였다.

• Journal of Power Electronics
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• 제19권5호
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• pp.1303-1314
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• 2019

This paper studies the harmonic characteristics of ship electric propulsion systems and their treatment methods. It also adopts effective measures to suppress and prevent ship power systems from affecting ship operation due to the serious damage caused by harmonics. Firstly, the harmonic characteristics of a ship electric propulsion system are reviewed and discussed. Secondly, aiming at problems such as resonant frequency and filter characteristics variations, resonance point migration, and unstable filtering performances in conventional passive filters, a method for fully tuning of a passive dynamic tunable filter (PDTF) is proposed to realize harmonic suppression. Thirdly, to address the problems of the uncontrollable inductance L of traditional air gap iron core reactors and the harmonics of power electronic impedance converters (PEICs), this paper proposes an electromagnetic coupling reactor with impedance transformation and harmonic suppression characteristics (ECRITHS), with the internal filter (IF) designed to suppress the harmonics generated by PEICs. The ECRITHS is characterized by both harmonic suppression and impedance change. Fourthly, the ECRITHS is investigated. This investigation includes the harmonic suppression characteristics and impedance transformation characteristics of the ECRITHS at the fundamental frequency, which shows the good performance of the ECRITHS. Simulation and experimental evaluations of the PDTF are carried out. Multiple PDTFs can be configured to realize multi-order simultaneous dynamic filtering, and can effectively eliminate the current harmonics of ship electric propulsion systems. This is done to reduce the total harmonic distortion (THD) of the supply currents to well below the 5% limit imposed by the IEEE-519 standard. The PDTF also can eliminate harmonic currents in different geographic places by using a low voltage distribution system. Finally, a detailed discussion is presented, with challenges and future implications discussed. The research results are intended to effectively eliminate the harmonics of ship electric power propulsion systems and to improve the power quality of ship power systems. This is of theoretical and practical significance for improving the power quality and power savings of ship power systems.