• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.293-295
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• 1991

In this study, we investigated the possibilty that $Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3-PbZrO_3$ ceramics with strontium substitutions could be used for piezoelectric sounders. Piezoelectric buzzer is one of them. By partially substituting Sr for Ph, dielectric constants had values greater than 2000, the value proper piezoelectric buzzer, piezoelectric constant($d_{31}$) had a maximum value, 298 $[10^{-12}C/N]$, at the Sr 5 mol % substitution. Sound level of piezoelectric buzzer had the highest value of 91 dB at the Sr 5 mol % substitution.

• Journal of Microbiology and Biotechnology
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• v.5 no.5
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• pp.269-273
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• 1995

A thermotolerable restriction endonuclease. Svil, found in Streptomyces violochromogenes D2-5 was purified. For the purification, streptomycin sulfate and ammonium sulfate precipitation was used. Ph osphocellulose P-ll, DEAE-Cellulose and Sephacryl-S200 HR colum chromatography were also performed. The purified enzyme was found to be homogeneous and the molecular weight of the enzyme estimated by polyacrylamide gel electrophoresis containing 0.1$%$ SDS was about 32, 000 daltons. The recognition sequence and cleavage site of the enzyme were determined to be $5^1$-$TT\downarrow CGAA$-$3^1$ which is the same sequence as that of Asull. Unlike Asull, however, the Svil shows high thermal stability.

• Polymer(Korea)
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• v.39 no.3
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• pp.499-505
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• 2015

Polyorganosiloxane having controlled cross-linking density and phenyl group content were prepared by dimethyldimethoxysilane (DMDMS), methyltrimethoxysilane (MTMS) and phenyltrimethoxysilane (PTMS). The effect of cross-linking density and phenyl group content on the physical properties of siloxane resin and its coated film have been invetigated. Si-NMR results confirmed that synthesized siloxane resins have equivalent D $T^{Me}$ $T^{Ph}$ structures according to applied mole ratios of DMDMS, MTMS and PTMS. Polyorganosiloxane having higher cross-linking density with high phenyl content showed the high molecular weight and increasing phenyl content resulted in higher refractive index as well as better thermal stability. Cross-linking density is more important factor than phenyl content to obtain higher pencil hardness of coated film on the glass. Our results concluded that even polyorganosiloxanes having similar siloxane structures show different physical properties as function of cross-linking density and phenyl content in polyorganosiloxane.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.35-45
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• 2006

강원도 홍천일대의 지역은 경기육괴의 편마암이 주암종으로 이루어진 지역으로 대규모의 홍천단층이 지나고 있다. 과거 이 단층대 부근에서 건설된 도로건설시에 발생된 많은 절토사면의 붕괴를 통해 그 원인 파악 및 차후 고려해야 할 사항을 파악하는 것이 매우 중요한 과제 중에 하나이다. 본 논문은 붕괴를 토대로 붕괴의 원인 및 대책방안을 파악하고자 한다. 홍천일대의 사면붕괴를 유발시키는 원인으로는 크게 두 가지 지질구조적인 요인을 들 수 있는데 하나는 사면방향으로 발달하는 편마암내에 발달하는 엽리면을 따라 붕괴가 발생되는 사례가 있고 둘째는 단층파쇄대 및 단층대를 따라 붕괴가 발생되는 원인으로 대별할 수 있다. 두 번째의 요인은 비교적 규모가 큰 사면붕괴를 유발하게 되고 막대한 복구비용이 수반되는 결과를 초래하게 된다. 이러한 단층의 수반에 의해 발생되는 절토사면은 대책방안으로 사면경사완화 방안, 앵커 및 억지말뚝과 같은 보강방법에 의해 안정화를 시키는 사례가 주를 이루었으며 차후 이 일대의 건설공사시에는 단층대의 방향 및 규모에 대한 조사를 세밀히 이루어져야 할 것이다.

• The Journal of the Korea Contents Association
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• v.10 no.7
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• pp.305-316
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• 2010

The impotance of Radiological science is greater due to development of Science and technology in Medical and Engineering. people who research specific area thought interdisciplinary approach, convergence is essential to pioneer a new field, receive attention was that interdisciplinary approach was needed. so investigating graduate system of radiological science, advanced country, designed to fit their country, could propose reference. the results show, in the university of offered with Master Degree operated program for Clinical experts(Sonography Specialist, Radiation Theraphy Specialist and Nuclear Medicine Specialist)and offered with Ph.D Degree operated program for Scientist and physicist (Nuclear Scientist, Medical Physicist). Note that by this, advanced graduate school program will enable us to become a reader of academia, play a leading role in the world.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.139-144
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• 2009

The generation of small hydropower as compared to other different developed environmental methods produces one of the clean energies. In such manner, various application system development through IT technique is being developed for an advanced small hydropower energy resources data mining. However, existing data analysis of New & Renewable Information System for small hydropower resources application is incomplete therefore it limits expressing these information on the Web. Thus for positive usage of small hydropower resources, a more systematic and precise analysis system should be built. This study seeks to develop a map of the domestic small hydropower resources problems to further improve small hydropower resources, developed through Package Tool which can accurately evaluate a wide range of small hydropower basin in a short period of time. Small hydropower Package Tool was calculated using existing Analysis System small hydropower resources which did not provide diverse capabilities resulting to 840 standard basin classified by A and facility capacity, etc., and to assume a 40% annual capacity, expected annual electricity production was calculated. Small hydropower for the national water system of small hydropower resources potential calculated in terms of resources for the development of small hydropower will be utilized as basic data.

• Reproductive and Developmental Biology
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• v.35 no.2
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• pp.167-174
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• 2011

Acute ischemic stroke results from sudden decrease or loss of blood supply to an area of the brain, resulting in a coinciding loss of neurological function. The antioxidant action of melatonin is an important mechanism among its known effects to protective activity during ischemic/reperfusion injury. The focus of this research, therapeutic efficacy of melatonin on recovery of neurological function following long term treatment in ischemic brain injured rats. Male Sprague-Dawley rats (n=40; 8 weeks old) were divided into the control group, and MCAo groups (Vehicle, MT7 : MCAo+ melatonin injection at 7:00, MT19 : MCAo+melatonin injection at 19:00, and MT7,19 : MCAo+melatonin injection at 7:00 and 19:00). Rat body weight and neurological function were measured every week for 8 weeks. After 8 weeks, the rats were anesthetized with a mixture of zoletil (40 mg/kg) and xylazine (10 mg/kg) and sacrificed for further analysis. Tissues were then collected for RNA isolation from brain tissue. Also, brain tissues were analyzed by histological procedures. We elucidated that melatonin was not toxic in vital organs. MT7,19 was the most rapidly got back to mild symptom on test of neurological parameter. Also, exogenous melatonin induces both the down-regulation of detrimental genes, such as NOSs and the up-regulation of beneficial gene, including BDNF during long term administration after focal cerebral ischemia. Melatonin treatment reduced the loss of primary motor cortex. Therefore, we suggest that melatonin could be act as prophylactic as well as therapeutic agent for neurorehabilitative intervention.

• Reproductive and Developmental Biology
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• v.35 no.2
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• pp.143-149
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• 2011

Arthritis is a common disease in aged people, and is clinically divided into rheumatoid arthritis (RA) and osteoarthritis (OA). Although common symptoms such as pain are present, the underlying pathological mechanisms are slightly different. Therefore, the objectives of the present study were to compare joint damage induced by RA and OA by analyzing the major morphological and molecular differences, and to propose a suitable therapeutic intervention based on the pathophysiological conditions of bones and joints. For the RA animal model, 8-week-old DBA1/J mice were immunized with bovine type II collagen emulsified in complete Freund's adjuvant (CFA). Normal C57BL/6 mice (over 2 years of age) were used for OA. The clinical arthritis score was calculated using a subjective scoring system, and paw thicknesses were measured using calipers. The serum TNF ${\alpha}$ level was analyzed using an ELISA kit. Micro-CT was used to identify pathological characteristics and morphological changes. In collagen-induced RA mice, there were increased ankle joint volumes and clinical scores (p<0.01). The concentration of TNF ${\alpha}$ was significantly increased from 3 to 7 weeks after immunization. Micro-CT images showed trabecular bone destruction, pannus formation, and subchondral region destruction in RA mice. OA among aged mice showed narrowed joint spaces and breakdown of articular cartilage. This study suggests that a careful therapeutic intervention between RA and OA is required, and it should be based on morphological alteration of bone and joint.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.1
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• pp.30-37
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• 2004

This study investigated the structural characteristics of Taxus cuspidata communities on Mt. Hambaek. The vegetation consisted of 9 species in the T$_1$(tree) layer, 35 species in the T$_2$(subtall tree) layer, 28 species in the S(shrub) layer, and 69 species in the H(herb) layer. The dominant species of the T$_1$ layer was Taxus cuspidata and that of the T$_2$ layer was Acer tschonoskii var, rubripes. The dominant species of the S layer was Tripterygium regelii, and the dominant species of the H layer was Pseudostellaria palibiniana. The diameter distribution of the dominant five species in the T$_1$ and T$_2$ layers indicates that these Taxus cuspidata forests may be gradually dominated by Quercus mangolica and by Tripterygium regelii. The composition of biological type was Ph-D$_1$-R$_{5}$-e.

• Reproductive and Developmental Biology
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• v.34 no.2
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• pp.81-88
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• 2010

Our objective of current study was to investigate the development of bone and heart in association with diabetes mellitus (DM). DM was induced by administering an intraperitoneal injection of streptozotocin (STZ; 60 mg/kg) to 4-week-old Sprague-Dawley rats. Body weight and blood glucose were monitored, and rats were sacrificed after 2 or 5 weeks. The left ventricle (LV), including the interventricular septum, was weighed, and body weight and tibial bone length were assessed. Young diabetic rats showed reduced growth in terms of tibial length and body weight compared to controls. Moreover, diabetic males showed more significant growth suppression and reduced LV size than diabetic females. Morphometric analysis of tibiae from diabetic rats revealed suppressed bone growth at 2 and 5 weeks, with no difference between genders. STZ-induced diabetes decreased bone growth and retarded pre-pubertal heart development. As a result, diabetes may increase cardiovascular risk factors and lead to eventual heart failure. Therefore, new therapeutic approaches are required for diabetic children exhibiting growth retardation. Heart growth factor, exercise, and cardiopulmonary physical therapy may be required to promote heart development and physiological function.