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극저온 볼 밀링을 통한 Ibuprofen 분말의 나노화Ⅱ
조현갑(H.K. Cho),이경엽(K.Y. Rhee),백영남(Y.N. Paik),박훈재(H.J. Park),이상목(S.M. Lee) 한국정밀공학회 2004 한국정밀공학회 학술발표대회 논문집 Vol.2004 No.10월
Reducing the particle size of drug materials down to submicron is an important matter in pharmaceutical industry. Cryogenic milling technology is one of the mechanical milling processes, which is mostly utilized in refining grain size of metal and ceramics at extremely low temperature environment. This technique has not been readily studied in application to medical and biotechnology. This paper, therefore, describes the application of cryogenic milling process to reduce particle size of Ibuprofen. The shape and size of the Ibuprofen particle before and after the cryogenic ball milling process were analyzed. XRD analysis was performed to examine a change in crystallinity of Ibuprofen by the cryogenic ball milling process. The results showed that the size of Ibuprofen particles was reduced to 1/10 or less of its initial size. The results also showed that the degree of crystallinity of Ibuprofen was slightly reduced after cryogenic ball milling with nitrogen.
Al-Fe-Ni 공정복합합금의 응고속도에 따른 전기저항의 변화
이재갑,조현기 경북대학교 산업기술연구소 1988 産業技術硏究誌 Vol.17 No.-
Numerous researchs have been investigated concerning the mechanism of unidirectionally solidification and the relationships between microstructure and growth rate in eutectic alloys. Although it is expected that the anisotropic microstructure associated with eutectic should produced the interesting electrical properties, almost all studies on eutectic composite alloy have been investigated about morphology, mechanical properties and thermal stability. In the present study, changes of electrical resistivity according to cooling rate in Al-Fe-Ni eutectic composite alloy is investigated. The obtained results are as follows; As cooling rate(R) increased, electrical resistivity of Al-Fe-Ni eutectic composite alloy at 520℃ increased with increaseing of fineness of eutectic fibers and formation of cellular structure. The higher the cooling rate, the higher the temperature dependence of electrical resistivity and the lower the stability of eutectic composite alloy, respectively.
최양일,조현갑,김일석 ( Y . I . Choi,H . G . Cho,I . S . Kim ) 한국축산학회 1998 한국축산학회지 Vol.40 No.1
This study was undertaken to investigate the pH, sensory and storage characteristics of 7 domestic chilled porks during 21 days of storage at 4℃. The pH values of chilled porks at 0 day of storage were 5.47∼5.67. Until the 21 days of storage period, the pH values of all chilled porks appeared to be normal. 1n the proximal analysis of chilled porks, the ranges of moisture and fat contents were larger than the other contents. However, all the chilled porks contained more than s% fat content and showed deposit of intramuscular fat well enough. In visual color scores, all the chilled porks showed high color scores until 14 days of the storage period except one sample of PSE(Pale, soft, exudative) meat. In sensory flavor scores, all the chilled porks showed similar scores and there was no sex odor problem. In sensory juiciness and tenderness scores, there were little differences among the porks at 0 day of storage, but after 3 days all the porks showed increased scores resulting from the aging effect until the 14th day of storage period. During the 21 days of storage at 4 C, the VBN (volatile basic nitrogen) values of chilled porks were in safe range until the 14th day of storage and the TBA(2-thiobarbituric acid) values of chilled porks were in very safe range until the 2lst day. In the total microbial counts, there were little differences among the porks at 0 day of storage, but they showed safe ranges(below the 106 Colony forming unit/g) until the 14th day. However, they reached the putrefaction ranges the 21st day of storage. In the coliform bacteria counts, 3 chilled porks among 7 companies showed coliform bacteria counts, but the count numbers were not high. However, better and/or tighter pork quality control should be necessary during the slaughtering and processing lines.