• 한국화재소방학회논문지
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• 제26권3호
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• pp.91-99
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• 2012

분말소화기를 조작하거나 해체하는 과정 중에 아주 드물게 사상자가 발생하는 경우가 있다. 부식된 분말소화기는 조작 중 또는 해체(폐기)과정 중에 폭발하면 로켓과 같이 위쪽으로 솟아오르면서 소화기 조작자나 해체과정 중인 사람의 머리나 가슴, 목 부위 등을 쳐서 사상사고를 발생하게 한다. 이 논문에서는 분말소화기파열사고사례를 알아본 후, 파열사고의 원인과 파열로 인한 반동력, 예방대책에 대해 알아보았다. 소화기 파열사고의 예방대책으로 훈련이나 교육에 부식된 소화기의 사용 자제, 부식된 소화기에 대한 위험성 교육 및 홍보, 기설치 가압식분말소화기에 파열위험성 표시, 내용연수 표시 의무화, 일정기간 경과 소화기에 대한 수압검사 제도의 도입 검토, 폐소화기 회수시스템 구축, 폐소화기의 재활용시스템 구축, 노후소화기관련 상담창구 운영 등을 제안하였다.

• 한국식품저장유통학회지
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• 제7권4호
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• pp.389-394
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• 2000

단감의 수확 및 저장 중에 발생한 불량과실을 이용할 목적으로 분말화하기 위한 기초연구로서 본 실험을 행하였다. 일반성분 조성은 조단백질, 조지방, 조회분의 순으로 열풍건조 처리구는 0.9-1.1%, 15.0-39.0%, 2.3-3.3%이었으며, 동결건조 처리구는 1.3-2.2%, 27.0-49.0%, 2.5%로 나타났다. 무기성분 조성은 열풍과 동결건조 처리구 모두 potassium, magnesium, phosphorus; calcium, sodium이 주요 무기성분이었으며, 다른 미량원소는 약 3.00ppm 이하였다. 주요 지방산 조성은 열풍과 동결건조 처리구에서 capric acid, lauric acid tridecanoic acid, palmitic acid, palmitoleic acid, oleic acid, linoleic acid, linolenic acid 순으로 나타났다. 동결건조 처리구의 아미노산 조성은 aspartic acid, glutamic acid가 주요 아미노산이었다. 전체적으로 열풍건조 처리구보다는 동결 건조 처리구가 다소 높은 결과를 보였다. 열풍과 동결건조에 의한 분말 제조에서는 변색과 영양적인 측면을 고려할 때 열풍건조 보다는 동결건조가 우수한 결과를 보였으며, 열풍건조가 시간은 단축되었으나 얇게 펴서 건조해야 하는 단점이 있었으며, 단순한 열풍건조 만으로는 대량생산에 의한 분말 제조는 어렵고 좀더 보완적인 방법이 강구되어야할 것으로 생각된다. 이에 반해 동결건조에 의한 건조방법은 건조시간이 다소 걸리기는 했으나 딱딱해지거나 변색의 우려가 없으며 영양학적으로도 매우 안정적이었다. 이상의 결과를 평가해 볼 때 열풍건조에 의한 분말 제조는 구체적인 보완이 필요하며, 동결건조에 의한 분말 제조가 열풍건조에서보다 우수한 것으로 결과가 나타났다. 따라서, 파찌감의 분말건조 방법은 동결건조가 효율적일 것으로 생각된다.

• 약학회지
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• 제42권3호
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• pp.284-289
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• 1998

The effect of reaction condition, solvent addition and thermal treatment on the bulk density, crystallinity and chemical properties of the freeze-dried cefazohn sodium was inves tigated to prepare the cefazolin sodium powder for injection with good flowability. Crystalline cefazolin sodium powder with high untapped-bulk density (about 45%) and low compressibility (about 40%) was obtained by solvent addition to the very highly concentrated cefazohn sodium solution followed by subsequent thermal treatment before freeze-drying. The desirable solvent was low substituted alcohol such as isopropyl alcohol and anhydrous ethanol with the final concentration of about 9%. The pH adjustment and nitrogen gas purging during the reaction did not give significant effect on the chemical properties such as content, color, transmittance and pH of the reconstituted cefazolin sodium aqueous solution.

• 한국분말재료학회지
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• 제4권4호
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• pp.304-309
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• 1997

The synthesis of W-l5wt%Cu nanocomposite powder by hydrogen reduction of ball milled W-Cu oxide mixture was investigated in terms of powder characteristics such as particle size, mixing homogeneity and micropore structure. It is found that the micropores in the ball milled oxide (2-50 nm in size) act as an effective removal path of water vapor, followed by the formation of dry atmosphere at reaction zone. Such thermodynamic condition enhances the nucleation of W phase but suppresses the growth process, being in favor of the formation of W nanoparticles (about 21 nm in size). In addition, the superior mixing homogeneity of starting oxide mixture turned out to Play a significant role for forming extraordinary chemical homogeneity of W-l5wt%Cu nanocomposite powder.

• 한국세라믹학회지
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• 제16권1호
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• pp.13-20
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• 1979

High purity alumina has been extracted form low grade Korean alunite. Alunite ore was treated by 15% $NH_4OH$ solution, followed by 10% $H_2SO_4$ leaching and metallic impurities such as Fe and Ti were removed by solvent extraction method. Alumina prepared by the extraction process was 99.9% in purity. Hot Petroleum Drying Method has been employed for the preparation of uniformly fine alumina powder, using chemical reagent aluminum sulfate and ammonium aluminum sulfate extrated from Korea alunite. The sinterability of alumina powder prepared by Hot Petroleum Drying Method was shown to be improved in comparison with the one treated by other methods such as ball milling method, but dry pressing was difficult due to the agglomeration of calcined powder. The best slip of alumina powder prepared by Hot Petroleum Drying Method contained a lower soild content than the one treated by other methods. The alumina body formed by soild and drain casting with the former alumina powder showed a higher sintered density.

• 한국결정성장학회지
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• 제18권5호
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• pp.200-204
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• 2008

기계화학공정(MCP; Mechano Chemical Process)은 원료 분말이 기계적인 에너지로 인해 상 형성이 활성화되기 때문에 기존의 볼밀링을 이용한 고상반응에서 필수적인 높은 온도에서의 하소 공정이 필요하지 않다. 본 연구에서는 고 에너지 MCP 방법을 이용하여 perovskite 구조를 가지는 PLT 나노 분말을 제조하였다. 특히, 일반적으로 출발물질로 염을 이용하는 것과 달리 산화물을 원료 분말로 사용하여 어떠한 열처리 공정 없이 PLT 나노 분말을 합성하였다. 또한 건식으로 밀링을 하여 분말 건조 공정이 필요 없어서 공정이 간단하다. MCP 밀링은 시간 별로 12시간까지 진행하였으며, 제조된 분말의 상 분석과 결정면 분석 결과 3시간 이후에는 perovskite 구조의 순수한 PLT 상을 형성하였다. 또한 마이크로 크기의 원료 분말이 밀링 3시간이 지나자 약 20 nm 크기의 균일한 나노 입자가 생성되었다.

• 한국잡초학회지
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• 제17권2호
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• pp.135-138
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• 1997

Sulfonylureas are highly active herbicides which can be applied at very low rate(10-50g/ha) to control broadleaf weeds. The nature of this category of compound is, however, very unstable toward hydrolysis. Therefore, the preparation of these compounds as liquid formulation was not possible. Most of the current formulations of sulfonylurea are in dry forms such as water dispersible granule or wettable powder. Even in these dry forms, the active ingredients also encounter significant chemical decomposition. This study involves the preparation of the sulfonylurea salts by reacting the parent compound with base such as sodium hydroxide. The salt becomes stable toward hydrolysis and it turns soluble when diluted with water. This discovery makes the preparation for liquid formulation or soluble granule of sulfonylurea possible. The stoichiometry of base added to the neutral sulfonylurea is controlled quite precisely. The base has to be added enough to quench the acidic impurities in the technical material and to convert the active ingredient into salt. However, the base should not be overused to cause further saponification of the sulfonylurea salts. The chemical nature of these compounds is presented and the chemical reaction is described. New soluble liquid formulation and solid granule formulation of sulfonylurea are suggested.

• 한국분말재료학회지
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• 제9권4호
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• pp.273-279
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• 2002

In this study, the WC-10 wt.%Co nanopowders doped by grain growth inhibiter were produced by three different methods based on the spray conversion process. Agglomerated powders with homeogenous distribution of alloying elements and with internal particles of about 100-200 nm in diameter were synthesized. The microstructural changes and sintering behavior of hardmetal compacts were compared with doping method and sintering conditions. The microstructure of hardmetals was very sensitive to doping methods of inhibitor. Nanostructured WC-Co hardmetal powder compacts containing TaC/VC doped by chemical method instead of ball-milling shown superior sintering densification, and the microstructure maintained ultrafine scale with rounded WC particles.

• Archives of Pharmacal Research
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• 제16권3호
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• pp.227-230
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• 1993

A new device to detect methamphetamine (MA), amphetamine(A) and its metabolites in urine was developed using the paper strip method and the test tube method of dry chemical reagents. The reagent containing tetrabromophenolphthalein ethyl ester (TBPE) and borax. For the TBPE paper strip method, a device was prepared with a window at each end of the reagent paper strip ; one window is for the sample application, and the other window is for the methylene chloride. The diffused sample from one window reacts with reagent in the paper and produces color at the point where it meets with methylene chloride which has diffused form the other side. A positive smaple produces as red-purple color and the negative sample a greenish color, with a detection limit of 5-10 ppm. The result can be obtained within one minute. For the TBPE test tube method which contains dry reagents, the detection limit is 5 ppm and the result can be obtaineed within 30 seconds, however the carry-on is not as convenient as the paper strip method. The performance of both methods were evlauated by comparing with the results of gas chromatography (GC) and fluorescence polarizaiton immunoassay (FPIA). The results were proven that both methods were useful as primary screening reagents to detect MA in urine and in dry powder.

• 한국염색가공학회지
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• 제21권1호
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• pp.10-20
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• 2009

The objective of this study is to investigate the efficacy of leaf powder colorants as substitutes for traditional fresh juice extract dyeing. Three kinds of leaf powder colorants were prepared by freeze drying method with or without deep freezing as pre-treatment: one powder colorant from fresh leaf juice with deep freezing; two kinds of powder colorant from fresh leaves with and without deep freezing. Their dyeing properties and storage stabilities were studied and compared with the traditional fresh juice extract dyeing. The presence of indigo in the powder colorants was confirmed by UV/Visible absorption spectra. They showed absorption peak at 602nm which was same with indigo absorption peak. Dyeing was done at low temperature around 6$^{\circ}C$. All three powder colorants produced B colors on silk fabrics, showing similar color to the one dyed traditionally with fresh juice extract. The powder colorants from leaves gave higher color strength than the powder from leaf juice. The powder colorant prepared from leaves with deep freezing was the most stable for long term storage as its color and color strength were not changed after 360 days. So, this was used for further dyeing to study the effects of concentration and repeat dyeing on color strength and colorfastness. Fastnesses to dry cleaning and rubbing were fairly good above 4 rating. Further study is needed to improve light fastness. It was concluded that the leaf powder colorant with deep freezing could be used as a substitute for traditional juice extract dyeing at all seasons.