• Journal of Pharmaceutical Investigation
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• 제21권3호
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• pp.125-132
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• 1991

Using X-ray crystallography powder diffraction, the quantitative representation method of preferred orientation of particles ill tablets was developed. Selected faces of a tablet. the upper surface and faces cut parallel and normal to the upper surface, were presented to an X-ray beam and X-ray diffraction patterns for these faces were measured. The effects of particle size. tableting pressure, and particle form on the preferred orientation were also investigated. It was also recognized that the degree of anisotropy in terms of capping tendency was influenced by the preferred orientation of particles in tablets.

• 대한치과의사협회지
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• 제9권4호
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• pp.157-160
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• 1971

To compare the effects of various pulp capping agents that are usually applied to human pulp tissue, adult dogs were bred for a certain period and each capping agent was applied experimentally to pulp tissue after vital pulpotomy. Histological observations are as follows. 1) In comparison between methods of vital pulpotomy, one and two appointment method, different courses of healing were observed. In one appointment method, the granulation tissue formation at the amputation sur face of pulp tissue had a tendency to be transformed to scar tissue formation. In two appointment method, more transformation than that of one appointment method from scar tissue to dentin matrix formation were observed. 2) Histologic changes that have appeared in pulp tissue are a) fixation at outer layer b) degeneration at middle layer c) hyperemia and round cell infiltration at inner layer 3) With use of formocresol mixed zinc oxide powder in two appointment method complete formation of dentin matrix were observed. 4) Among the methods and aagents described above formocresol mixed zinc oxide powder in two appointment method appeared to be relatively effective.

• 공업화학
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• 제23권4호
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• pp.388-393
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• 2012

말단캡핑제(end capping agent) 4종류와 함량별로 분지형 폴리카보네이트를 용융중합법으로 제조하였다. 합성된 분지형 폴리카보네이트의 화학구조는 FT-IR과 $^{1}H-NMR$ 스펙트럼을 이용하여 확인하였으며, 말단캡핑제의 반응여부는 FT-IR 스펙트럼의 수산기($3500\;cm^{-1}$) 존재여부로 확인하였다. 평균 분자량 및 분자량 분포도, 유리전이 온도 및 분해온도는 GPC, DSC와 TGA를 이용하여 측정하였다. 말단캡핑제의 화학구조에 따라 평균 분자량이 증가 또는 감소를 나타내었으며, 말단캡핑제로 4-tert-butylphenol (TBP)이 사용되었을 때 최적의 분자량 조절 결과를 나타내었다. 말단캡핑제의 함량이 증가할수록 평균분자량은 감소하였고, 4-tert-butylphenol이 0.05 mol%가 첨가될 때 폴리카보네이트의 대형 사출물 가공에 적합한 20000 정도의 수평균분자량을 나타내었다. 분지형 폴리카보네이트의 용융점도는 분자량이 감소할수록 감소하였으며, shear thinning effect에는 큰 영향을 주지 않음을 확인하였다.

• Archives of Pharmacal Research
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• 제28권4호
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• pp.493-501
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• 2005

Effect of solvents on physical characteristics and release characteristics of monolithic acetaminophen (APAP) hydroxypropylmethylcellulose (HPMC) matrix granules and tablets were examined. Various types and amounts of solvents were employed for granulation and coating. APAP and other excipients were mixed and were then wet-granulated in a high-speed mixer. The dried granules were then directly compressed and film-coated with low viscosity grade HPMC. As the amount of water increased, the size of granules also increased, showing more spherical and regular shape. However, manufacturing problems such as capping and lamination in tableting occurred when water was used alone as a granulating solvent. The physical properties of HPMC matrix granules were not affected by the batch size. The initial release rate as well as the amount of APAP dissolved had a tendency to decrease as the water level increased. Addition of nonaqueous solvent like ethanol to water resulted in good physical properties of granules. When compared to water/ethanol as a coating solvent, the release rate of film-coated HPMC matrix tablets was more sensitive to the conditions of coating and drying in methylene chloride/ethanol. Most of all, monolithic HPMC matrix tablet when granulated in ethanol/water showed dual release with about $50\%$ drug release immediately within few minutes followed by extended release. It was evident that the type and amount of solvents (mainly water and ethanol) were very important for wet granulation and film-coating of monolithic HPMC matrix tablet, because the plastic deforming and fragmenting properties of material were changed by the different strengths of the different solvents.

• 한국산학기술학회논문지
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• 제17권5호
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• pp.10-16
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• 2016

본 연구에서는 PAA를 사용한 액상환원법에 의해 은 나노용액을 합성하는 과정에서 실험변수로서 PAA의 분자량, PAA의 첨가량, 환원제, 분산제, 유기용매 등을 사용하여 은 나노입자의 크기와 분산특성을 조사하였다. UV-Visable spectrophotometer로 은 나노입자의 생성을 확인하였으며, SEM으로 nanometer 영역의 입자크기와 분산특성을 알아냈다. 초음파 파쇄시간이 증가할수록 은 나노입자의 덩어리가 작아지는 경향을 나타내며 3시간 이후에는 1-5개의 작은 덩어리 형태로 은 나노입자가 분산되었다. 초음파 파쇄와 함께 Copolymer with pigment affinic group을 주성분으로 하는 분산제인 BYK-192를 첨가해 주면 49.56-85.75 nm의 크기를 가진 비교적 구형에 가까운 균일한 은 나노입자가 균일하게 완전히 분산되는 되었다. PAA의 분자량이 증가할수록 은 나노입자의 평균크기가 36.82<50.66<56.06 nm 순으로 증가하였다. 또한 PAA의 첨가량이 늘어날수록 은 나노입자의 표면에 덧씌움 현상이 일어나서 은 나노입자의 크기가 커지는 것으로 나타났다. 환원제인 Hydrazine을 첨가하면 환원반응에 의해 많은 수의 핵이 생성되었기 때문에 상대적으로 작은 크기의 입자가 생성되었다. 유기용제(에타놀-아세톤)는 은 나노입자의 규칙적 배열을 도와주었다.