• 약학회지
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• 제41권5호
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• pp.615-621
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• 1997

Dehydropeptidase-I (DHP-I) was solubilized from porcine kidney by treatment with n-butanol and partially purified 19.25 fold by $(NH_4)_2SO_4$ precipitation, DEAE-Sepharose CL-6B ion exchange chromatography and Sephacryl S-300 HR chromatography with an overall yield of 19.16. DHP-I showed its optimal activity at pH 7.5 and 25$^{\circ}C$. Its activity was stable under neutral and alkaline conditions, but was disappeared under acidic condition. And DHP-I was heat-labile and its activity remained at 45$^{\circ}C$ for 3hrs. The enzyme was not inhibited by dicationic ions, while its activity was increased by $Co^{2+}$(1mM) and $Zn^{2+}$ (0.1mM). The enzyme was inhibited by EDTA and N-ethylmaleimide. The relative molecular mass of DHP-I was estimated to be approximately 100kDa by gel filtration chromatography. The $K_m$ value of DHP-I for glycyldehydrophenylalanine (GDHP) was 1.98mM. DWP20418 [(1R, 5S, 6S)-6-[1-(R)-Hydroxyethyl]-1-methyl-2-[(2S, 4S)-2-(piperazinylcarbonyl)-1-(R)-hydroxyethyl)pyrrolidine-4-thio]carbapen-2-em-3-carboxylic acid], compared with meropenem (MEPM), was rather easily hydrolized by DHP-I, while it was four times more resistant than imipenem (IPM) to DHP-I.

• 복식문화연구
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• 제18권1호
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• pp.109-117
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• 2010

편성물은 여러 가지 형태의 편성 조직을 얻기 위해서 횡편기나 환편기 등의 다양한 니트 편기를 이용하여 다양한 형태의 니트 편환과 조건에 의해서 편성을 하게 된다. 입체적인 형태의 니트 편지는 각기 다른 니트 편환 조직의 병용, 다양한 편사의 이용, 또는 여러 가지 가공공정 등을 거쳐서 얻을 수 있다. 본 연구는 컴퓨터화된 자동 횡편기를 이용하여 편성에 있어서 기본이 되는 조직인 리브편과 펄편의 편성조직을 효과적으로 혼합 편성하여 새로운 형태의 입체 니트구조를 갖는 편지를 개발하는데 그 목적이 있다. 이러한 입체 니트조직을 바탕으로 하여 몇 가지 다른 형태의 입체구조를 갖는 편성물을 개발하고, 새로운 형태의 니트 패션 의복을 제작한다. 또한 리브편과 펄편에 의한 입체 편성조직의 원리와 특성 등에 대하여 논한다.

• 공학논문집
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• 제2권1호
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• pp.133-138
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• 1997

Mullite 분말을 합성하는 제조공정에서 기존의 분말합성법은 $1300^{\circ}C$이상의 높은 온도와 긴 반응시간과 cost 면에서 비싸다는 문제점을 안고 있다. 따라서 본 연구에서는 비교적 제조공정이 간단하고 짧은 반응시간내에 낮은 온도에서 미립의 산화물계 분말을 합성할 수 있는 연소 합성법으로 mullite 분말을 합성하였다. 금속의 질산염, 미립의 $SiO_2$분말과 연료를 적정 mole비로 혼합하여 공정변수에 따라 mullite를 합성하고, 그의 물성을 조사하였다. Hot plate에서의 실험은 연료의 양에 관계없이 mullite는 합성되지 않았다. 그러나, $500^{\circ}C$ 열처리로 실험에서는 mullite와 약간의 alumina, cristobalite가 보였고, 특히 aluminum nitrate, silica, urea 각각의 조성이 화학양론비였을 때 거의 완벽한 mullite를 얻을 수 있었다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1999년도 춘계학술발표회 초록집
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• pp.5-5
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• 1999

A novel process is proposed to improve oxidation resistance of Ti-Al intermetallic compounds at elevated temperatures by both Cr addition and pre-sulfidation, where TiAl alloys withlor without Cr addition were sulfidized at 1173K for 86.4ks at a 1.3 Pa sulfur partial pressure in a $H_2-H_2S$ gas mixture. The pre-sulfidation treatment formed a thin Cr-Al alloy layer as well as 7~10 micrometer $TiAl_3$ and $TiAl_2$ layer, due to selective sulfidation of Ti. Oxidation resistance of the pre-sulfidation processed TiAl 4Cr alloy was examined under isothermal and heat cycle conditions between room temperature and 1173K in air. Changes in $TiAl_3$ into $TiAl_2$ and then TiAl phases as well as their effect on oxidation behavior were investigated and compared with the oxidation behavior of the TiAl-4Cr alloy as TiAl and pre-sulfidation processed TiAl aHoys. After oxidation for up to 2.7Ms a protective $Al_2O_3$ scale was formed, and the pre-formed $TiAl_3$ changed into $TiAl_2$ and the $Al_2Cr$ phase changed into a CrAlTi phase between the $Al_2O_3$ scale and $TiAl_2$ layer. The pre-sulfidation processed TiAl-4Cr alloy had very good oxidation resistance for longer times, up to 2.7 Ms, in contrast to those observed for the pre-sulfidation processed TiAl alloy where localized oxidation occurred after 81 Oks and both the TiAl and TiAl-4Cr alloys themselves corroded rapidly from the initial stage of oxidation

• 한국식품과학회지
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• 제27권4호
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• pp.439-444
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• 1995

Preparative conditions and characteristics of six-vegetable and fruit juice were studied for the effects of mixing ratio, heat treatment and addition of sugar, salt and organic acid. The vegetables and fruit used were carrot(Ct), cabbage(Cg), pear(Pr), cucumber(Cr), celery(Cy) and dongchimi(Di). From the sensory results of mixing ratio of three of binary mixtures of Cg-Pr(1:3):Ct-Di(1:4):Cr-Cy(3:1), two ratios of 5.0:2.5:2.5(V-6A) and 6.0:2.0:2.0(V-6B) were suggested optimal for six-vegetable and fruit juice. Addition of 2% sucrose and 0.3% NaCl improved the preference significantly. The pH 4.0 for V-6A and pH 3.5 for V-6B were more prefered when pH was adjusted by citric acid. Heating the juice at $100^{\circ}C$ for 100 minutes slightly decreased pH and increased the acidity. Total solids and viscosity were also decreased by heating. All of those changes were more significant in V-6B than V-6A, probably due to lower pH. Heating the juice resulted in a slight decrease in L value and an increase in a and b values. Heating at $100^{\circ}C$ caused an increase in moldy flavor and a decrease in fresh vegetable flavor while heating at $80^{\circ}C$ for 20 minutes changed them little.

• 한국식품과학회지
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• 제36권2호
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• pp.299-305
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• 2004

유전자재조합 옥수수 Bt11을 이용하여 가공조건에 따른 유전자의 변화를 조사한 결과, 직접 가열하여 탄화 혹은 갈변 되거나 수분을 함유한 멸균조건에서는 내재유전자 및 삽입유전자는 완전히 소실되는 것으로 나타났다. 반면, 유탕처리나 건조상태의 멸균, 단순 건조 등의 방법으로는 유전자의 많은 양이 보존됨을 알 수 있었다. 당화효소를 이용한 효소처리에서는 유전자에 영향을 주지 않는 것으로 나타났으며 실제 가공생산 공정에서도 전분당의 생산공정에서 효소처리 단계에서는 영향이 없었고 이후 당화액을 여과하는 과정에서 유전자가 소실되는 것으로 나타났다. 이러한 모의 실험결과를 토대로 가공식품을 65종 모니터링 분석한 결과 13.6%인 9종에서 유전자재조합 옥수수를 사용한 것으로 확인됐으며, 콘칩 등의 과자류에서 사용이 많은 것으로 나타났다. 특히 미국산 옥수수 분말을 사용한 율무차, 쇠고기 수프, 옥수수 수프, 식빵믹스 등에서 GM옥수수의 검출빈도가 높았으며, 옥수수통조림, 전분당, 식용유, 팝콘류 등에서는 검출되지 않았다.

• 대한의용생체공학회:의공학회지
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• 제22권6호
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• pp.511-518
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• 2001

치과용 고-Pd계 합금인 76.5wt.%Pd-11 6%Cu-7.2%Ga계 및 77.3%Pd-6.0%Ga계 합금의 주조. 탈개스 및 세라믹소성처리 후 부식저항성을 0.9%NaCl 및 Fusayama 전해액에서 동전위분극법을 이용하여 평가하였다. 미세조직의 변화에 따라 약간의 부식속도 차이를 나타내었으나 이는 미미하여 치과재료로서의 부식저항성은 문제가 없는 것으로 판단되었다 합금조성에 따른 부식저항성은 77.3%Pd-6.0%Ga계 합금이 76.5%Pd-11.6%Cu-7.2%Ga계 합금보다 우수한 것으로 나타났다. 이러한 결과는 76.5%Pd-11.6%Cu-7.2%Ga계 합금은 급냉조건과 Cu의 첨가로 공정반응을 촉진시켜 미세조직에 편석 및 석출물들이 존재했기 때문이었으며 77.3%Pd-6.0%Ga계 합금은 기지조직이 고용체로 구성되어 부식저항성 이 우수하였다.

• 한국표면공학회지
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• 제52권6호
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• pp.298-305
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• 2019

We investigated a correlation between morphology and photoelectrochemical properties of TiO₂ nanotubes fabricated by well-controlled anodization processes. Anodization in an ethylene-glycol-based electrolyte solution accelerated the rapid grow rate of TiO₂ nanotubes, but also cause problems such as delamination at the interface between TiO₂ nanotubes and a Ti substrate, and debris on the top of the nanotube. The applied voltages for the anodization of TiO₂ were adjusted to avoid the interface delamination. The heat treatment and the anodizing time were also controlled to enhance the crystallinity of the as-prepared TiO₂ nanotubes and to increase the surface area with the varied length of the anodized TiO₂ nanotubes. Additionally, a 2-step anodization process was utilized to remove the debris on the tube top. The photoelectrochemical properties of TiO₂ nanotubes prepared with the carefully tailored conditions were investigated. By removing the debris on TiO₂ nanotubes, applied bias photon-to-current efficiency (ABPE) of TiO₂ nanotubes increased up to 0.33%.

• 한국의류학회지
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• 제35권11호
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• pp.1297-1308
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• 2011

This research investigates the application of ZnO (zinc oxide) nanoparticles and $TiO_2$ (titanium dioxide) nanoparticles to polypropylene nonwoven fabrics via an electrospinning technique for the development of textile materials that can decompose harmful gases. To fabricate uniform ZnO nanocomposite fibers, two types of ZnO nanoparticles were applied. Colloidal $TiO_2$ nanoparticles were chosen to fabricate $TiO_2$ nano- composite fibers. ZnO/poly(vinyl alcohol) (PVA) and $TiO_2$/PVA nanocomposite fibers were electrospun under a variety of conditions that include various feed rates, electric voltages, and capillary diameters. The morphology of electrospun nanocomposite fibers was examined with a field-emission scanning electron micro- scope and a transmission electron microscope. Decomposition efficiency of gaseous materials (formaldehyde, ammonia, toluene, benzene, nitrogen dioxide, sulfur dioxide) by nanocomposite fiber webs with 3wt% nano-particles (ZnO or $TiO_2$) and 7$g/m^2$ web area density was assessed. This study shows that ZnO nanoparticles in colloid were more suitable for fabricating nanocomposite fibers in which nanoparticles are evenly dispersed than in powder. A heat treatment was applied to water-soluble PVA nanofiber webs in order to stabilize the electrospun nanocomposite fibrous structure against dissolution in water. ZnO/PVA and $TiO_2$/PVA nanofiber webs exhibited a range of degradation efficiency for different types of gases. For nitrogen dioxide, the degradation efficiency was 92.2% for ZnO nanocomposite fiber web and 87% for $TiO_2$ nanocomposite fiber web after 20 hours of UV light irradiation. The results indicate that ZnO/PVA and $TiO_2$/PVA nano- composite fiber webs have possible uses in functional textiles that can decompose harmful gases.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 SMICS 2004 International Symposium on Maritime and Communication Sciences
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• pp.113-116
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• 2004

The materials showing high structure dispersion with functional properties were developed on the quartz base and those were obtained by mechano-chemical reaction technology. Depending on the processing conditions and subsequent applications the materials produced by mechano-chemical reaction show concurrently magnetic, dielectric and electrical properties. The obtained magnetic-electrical powders classified by aggregate complex of their features as segnetomagnetics, containing a dielectric material as a carrying nucleus, particularly the quartz on that surface one or more layers of different compounds were synthesized having thickness up to 10~50 nm showing magnetic, electrical properties and others. The similarity of the structure of surface layers of quartz particles subjected to mechano-chemical processing and nano-structure cluspol (clusters in a polymer matrics) material was also confirmed by the fact that the characteristics of ferromagnetic quartz of insulating nano-composite powder were changed with time, after its preparing process was completed. The magnetic permeability of the sample was decreasing within first two months down by 15~20 %. Then, the magnetic characteristics were almost stabilized steadily and continuously. The observed changes were related with defective structure of the particles, elastic stress relief, and changes of electron density and magnetic moment in deformation zones. This process of stabilization of the investigated properties could be intensified by the thermal annealing heat treatment in short time period of the nano-composite quartz powders at the temperature ranges of 100~15$0^{\circ}C$.