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Reduction and Spark Plasma Sintering of the W(Tungsten) Nanopowder Produced by the Electric Explosion of Wire Process (전기선폭발법으로 제조한 나노 W(텅스텐) 분말의 환원처리 및 방전플라즈마소결에 의한 조밀화)

  • Kim Ji-Soon;Kim Cheol-Hee;Park Eun-Ju;Kwon Young-Soon;Kim Jin-Chun;Lee Sung-Ho;Jung Dong-Ik
    • Journal of Powder Materials
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    • v.13 no.4 s.57
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    • pp.269-277
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    • 2006
  • [ ${\beta}-W(W_3O)$ ] oxide layer on the surface of each W(tungsten) nanopowder produced by the electric explosion of wire(EEW) process were formed during the 1vol.% air passivation process. The oxide layer hindered sintering densification of compacts during SPS process. The oxide phase was reduced to the pure W phase during SPS. The W nanopowder's compacts treated by the hydrogen reduction showed high sintered density of 94.5%. after SPS process at $1900^{\circ}C$.

Experimental Research on an Organic Rankine Cycle Using Engine Exhaust Gas (엔진 배기열 이용 유기랭킨사이클에 대한 실험적 연구)

  • Shin, Dong Gil
    • Journal of Energy Engineering
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    • v.21 no.4
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    • pp.393-397
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    • 2012
  • In this study, an organic Rankine cycle(ORC) for gas engine waste heat recovery for industry has been constructed and a performance analysis test has been carried out. Shell & tube style heat exchanger has been equipped on an engine exhaust manifold in order to absorb heat of engine exhaust gas into the working fluid(refrigerant R134a). Under 60 kW of engine power output, about 63 kW of engine exhaust gas heat was discharged and the proportion of heat recovered was 68~73% while 43~46 kW of heat was absorbed into working fluid. Consequently rated power output of ORC was 4.6 kW while the ratio of rated power output to engine exhaust gas heat was 7.3%.

Identification and Phylogeny of the Human Endogenous Retrovirus HERV-W LTR Family in Human Brain cDNA Library and Xq21.3 Region

  • KIM, HEUI-SOO;TIMOTHY J. CRO
    • Journal of Microbiology and Biotechnology
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    • v.12 no.3
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    • pp.508-513
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    • 2002
  • Human endogenous retroviral long terminal repeats (LTRs) have been found to be coexpressed with sequences of genes located nearby. It has been suggested that the LTR elements have contributed to the structural change or genetic variation of human genome connected to various diseases. The HERV-W family has been identified in the cerebrospinal fluids and brains of individuals with schizophrenia. Using a cDNA library derived from a human brain, the HERV-W LTR elements were examined and five new LTR elements were identified. These elements were examined using a YAC clone panel from the Xq21.3 region linked to psychosis that was replicated on the Y chromosome after the separation of the chimpanzee and human lineages. Fourteen elements of the HERV-W LTR were identified in that region. Those LTR elements showed a high degree of sequence similarity ($91.8-99.5\%$) with previously reported HERV-W LTR. A phylogenetic tree obtained from the neighbor-joining method revealed that new HERV-W LTR elements were closely related to the AXt000960, AF072504, and AF072506 from the GenBank database. The data indicates that several copy numbers of the HERV-W LTR elements exist on the Xq21.3 region and are also expressed in the human brain. These LTR elements need to be further investigated as potential leads to neuropsychiatric diseases.

Evaluation or various vehicles and O/W Microemulsions of Flurbiprofen as Transdermal Delivery System (경피제제로서 수종의 플루비프로펜 Vehicle과 O/W 마이크로에멀젼의 평가)

  • Lee, Gye-Won;Jee, Ung-Kil
    • Journal of Pharmaceutical Investigation
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    • v.28 no.3
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    • pp.141-149
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    • 1998
  • In order to reduce systemic side effects following administration, flurbiprofen was formulated as O/W microemulsion consisting of the surfactant, oil phase and aqueous phase. Particle size distribution, apparent viscosity, solubility and skin permeation of flurbiprofen in various vehicles and microemulsion were evaluated. The domain of O/W microemulsion s phase diagram had difference between oil types and the area of O/W microemulsion was wide distributed by adding to PG and cosurfactant than that of water alone. As increasing 10, 15 and 20% of Brij 97 content and 1, 2.5, 5% of oil content, the solubility of flurbiprofen in O/W microemulsions and various vehicles was $400{\sim}1,000$ and $10{\sim}500$ times higher than that of control. Also, apparent viscosity of soybean oil microemulsions was higher than that of IPM microemulsions and that of vehicle were increased as increasing vehicle content. Since skin permeation of flurbiprofen decreased as increasing viscosity, in each vehicle, it was not affected 2% ${\beta}-CD$ and decreased as increasing PG content and to 2, 5 and 10% of $HP-{\beta}-CD$. In O/W microemulsion, 5% soybean oil. 20% Brij 97 and 75% water(A-1) with high viscosity showed low skin penetration.

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SATELLITE ATTITUDE SENSING MODEL AND THEIR S/W DEVELOPMENT (인공위성 자세감지 모델과 그 S/W 개발)

  • 김영신;안웅영;김천휘
    • Journal of Astronomy and Space Sciences
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    • v.16 no.1
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    • pp.69-78
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    • 1999
  • We have developed an attitude sensing S/W system, one of modules of Mission Analysis System(MAS), which simulates attitude sensing data as almost the same as the real sensor of a satellite in orbit. When attitude elements($alpha,delta$) of a satellite and positions of Earth, Moon, and Sun are given, the S/W system calculates look angles and dihedral angles of each celestial bodies relative to the rotations axis of the satellite. It consists of two sub-modules : One is ephemeris service module which consider the perturbations of four planets(Venus, Mars, Jupiter, Saturn) for positions of Sun and Moon and 4 $\times$4 earth gravitational potential terms for a satellite's position. The other is attitude simulation module which generates attitude sensing data. Varying the rotational axis of a satellite and it's orbital elements, we simulated the generating attitude sensing data with this S/W system and discussed their results.

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A Novel Method for Production of Concentrated Purity Maltose Using Swollen Extruded Starch (Extrusion시킨 팽윤 전분을 기질로 한 새로운 Maltose 생산법)

  • Lee, Yong-Hyun;Kim, Dong-Sun;Shin, Hyun-Dong;Park, Jin-Seo
    • Microbiology and Biotechnology Letters
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    • v.22 no.1
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    • pp.106-113
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    • 1994
  • A novel method for production of concentrated purity maltose using swollen extruded corn starch was investigated. Degree of gelatinization of extruded starch suitable for maltose formation was found to be around 70%. The optimal amiunt of enzyme was 400 unit fungal $\alpha $-amylase per g of starch, and the reaction time was 12 hours. At extruded starch concentration of 300 g/l(w/v), maltose concentration and content were reached up to 220 g/l(w/v) and 77%(w/w), respectively. The maltose forming reaction was also successfully proceeded at high starch concentration of 700 g/l(w/v), however, the conversion yield and content were decreased. By the addition of extruded starch by fed-batch wise, the maltose concentration, purity, and conversion yield could be improved up to 465 g/l(w/v), 70%(w/w), and 0.63, respectively. The investigated maltose production process seems to have many potential advantages over the conventional process utilizing liquefied starch, and the feasibility for industrial application needs to be evaluated.

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The study on removal of slurry particles on W plug generated during tungsten CMP (WCMP에서 발생되는 W plug내 slurry particle제거에 관한 연구)

  • Yang, Chan-Ki;Kwon, Tae-Young;Hong, Yi-Koan;Kang, Young-Jae;Park, Jin-Goo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.11a
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    • pp.366-367
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    • 2006
  • In general, HF chemistry lifts off the particles during scrubbing after polishing and effectively removes particles. It is sometimes impossible to apply HF chemistry on W plug due to the degradation of electrical characteristics of a device. In this paper, a post W CMP cleaning process is proposed to remove residue particles without applying HF chemistry. After W CMP, recessed plugs are created, therefore they easily trap slurry particles during CMP process. These particles in recessed plug are not easy to remove by brush scrubbing when $NH_4OH$ chemistry is used for the cleaning because the brush surface can not reach the recessed area of plugs. Buffing with oxide slurry was followed by W CMP due to its high selectivity to W. The buffing polishes only oxide slightly which creates higher plug profiles than surrounding oxide. Higher profiles make the brush contact much more effectively and result in a similar particle removal efficiency even in $NH_4OH$ cleaning to that in HF brush scrubbing.

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The Changes of Body Fat Accumulation, Serum Lipids and Platelet Functions in Rat Fed the Diet Containing Different Common Oils in Korea: Sesame oil, Perilla oil, Rice Bran oil and Mixed oil (급원이 다른 식이 지방이 흰쥐의 지방대사와 혈소판 성상에 미치는 영향 -참깨유, 들깨유, 미강유 중심으로-)

  • 김숙희
    • Journal of Nutrition and Health
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    • v.26 no.5
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    • pp.513-523
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    • 1993
  • In this experiment, we investigated the hypolipidemic and antithrombotic effects of rats fed diets with different common oils in Korea for different feeding periods(4 weeks or 12 weeks), using Korean sesame oil, perilla oil, rice bran oil and mixed oil. W-3/w-6 ratio of each group was 0.001, 1.44, 0.03 and 0.112, respectively. P/S ratio of each group was 9.64, 10.49, 5.58 and 1.68, respectively. The result were as follows: 1) According to the age, body fat accumulation was increased. 2) Perilla oil(w-3 rich) decreased total lipid, triglyceride and total cholesterol, and increased HDL/total cholesterol ratio. 3) With regard to the compositono of platelet fatty acids, Perilla oil increased w-3/w-6 ratio of the platelet. Perilla oil lengthened bleeding time and decreased MDA(MalonDAdehyde) formation which determined in place of Thromboxane A2(TXA2) in platelet. This result can suggest that linoleic acid of perrilla oil seem to supress the conversion of linoleic acid to arachidonic acid(AA 20:4, w-6) and eicosapentaenoic acid(EPA, 20:5, w-3) trannnsformed from linolenic acid to suppress the conversion of arachidonic acid to TXA2. Since TXA2 is platelet-aggregating and vasoconstricting agent, the reduction of TXA2 tgeneration by platelet with increased linolenic acid intakes shows prologed bleeding time. In conclusion, w-3 rich perilla oil has strong hypolipidemic and antithrombotic effects by changing fatty acid profiles of the platelet.

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Study on Ejection Mitigation Impact Test about correlation between Vehicle and B.I.W(Body In White) Condition (FMVSS 226 Ejection Mitigation Impact Test의 시험품 단순화에 따른 인자들의 상관 관계에 대한 연구)

  • Kang, Mooncheol;Shin, Hyunhack;Oh, Hyungjoon
    • Journal of Auto-vehicle Safety Association
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    • v.7 no.4
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    • pp.16-19
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    • 2015
  • FMVSS226 Ejection Mitigation Impact Test is usually performed by real vehicle. But it is necessary to perform the test using by Reinforced B.I.W. with considering vehicle developing timing and roof rail airbag (RRAB) supplier capacity. We sometimes need tendency (quick data) instead of slow accurate data to fix RRAB design as proper timing. Test with Reinforced B.I.W. is helpful saving time and cost. But it should be confirmed how much different between vehicle conditioned test result and Reinforced B.I.W. conditioned test result. There are some points to be improved even in the test with vehicle. Understanding of deviation of Reinforced B.I.W. conditioned test result from vehicle conditioned test result is needed to get benefits with using Reinforced B.I.W. conditioned in the test.

Community Structure and Species Diversity of Fish across Spatial Scales in the Lower Reach of Seomjin River (섬진강 하류역에 서식하는 어류의 군집구조 및 공간 규모에서 종 다양성)

  • Huh, Man-Kyu;Seo, Jeoung-Yoon;Joo, Woo-Hong
    • Journal of Environmental Science International
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    • v.21 no.11
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    • pp.1361-1369
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    • 2012
  • A biological assessments of fish community structure were carried out in the lower reach of Seomjin River from May 2009 to November 2010. The collected fish from the six surveyed sites were 63 species belonging to 24 families, and 10 orders. Although species was different depending on sites, the numbers of individuals were not shown significance on sites. Locational dominant species were different. For example, the dominant species on May were Zacco platypus at W-1, Zacco temminckii at W-2, Acanthogobius flavimanus at W-3 and W-4, and Leiognathus nuchalis at W-5 and W-6. There is no seasonal differences in species. Species diversity was the best up to 2.64 on May at W-1 from 1.33 on November at W-6. As a result of an analysis about environmental factors for the numbers of fish species and individuals in each surveyed sites, the most effective groups were DO, BOD, and COD. The proportional difference was high on May than November between transient and asymptotic projections for population size and population growth rate for simulations starting at the current or theoretical stage distribution.