نتایج جستجو برای: Crystallinity

تعداد نتایج: 6032  

Journal: :Journal of biomedical materials research. Part B, Applied biomaterials 2010
Angela L Bruck K S Kanaga Karuppiah Sriram Sundararajan Jun Wang Zhiqun Lin

In this study, the friction and wear behavior of ultrahigh molecular weight polyethylene (UHMWPE) were evaluated as a function of polymer crystallinity in the presence of the phospholipid dipalmitoyl phosphatidylcholine (DPPC) dissolved in ethanol. Samples of UHMWPE were separately heat treated to get high and low crystallinity samples. Degree of crystallinity was evaluated using differential s...

Journal: :International journal of pharmaceutics 1999
V Kumar S H Kothari

The effect of compressional force on the crystallinity of low crystallinity cellulose (LCPC), microcrystalline celluloses (Avicel PH-101, PH-102 and PH-302 grades) and powdered cellulose (Solka Floc BW-100) has been investigated using an X-ray diffraction method. Microcrystalline and powdered celluloses showed an increase of about 10% in their crystallinities, compared to the values for the cor...

Journal: :Acta biomaterialia 2008
K S Kanaga Karuppiah Angela L Bruck Sriram Sundararajan Jun Wang Zhiqun Lin Zhi-Hui Xu Xiaodong Li

In this study the friction, wear and surface mechanical behavior of medical-grade ultra-high molecular weight polyethylene (UHMWPE) (GUR 1050 resin) were evaluated as a function of polymer crystallinity. Crystallinity was controlled by heating UHMWPE to a temperature above its melting point and varying the hold time and cooling rates. The degree of crystallinity of the samples was evaluated usi...

2012
Widi Astuti

Coal fly ash (CFA) generated by coal-based thermal power plants is mainly composed of some oxides having high crystallinity, like quartz and mullite. In this study, the effect of CFA crystallinity toward lead adsorption capacity was investigated. To get solid with various crystallinity, the solution of sodium hydroxide (NaOH) of 1-7 M was used to treat CFA at various temperature and reflux time...

Journal: :Kobunshi Kagaku 1959

برهانی زرندی, محمود ,

In this research, the effects of cooling rate and high energy electron beam irradiation on the change of crystallinity of polypropylene was investigated. For this work, samples of polypropylene heated to 230 ºC and then rapidly cooled with different speed of cooling. Crystalliny of samples were determined by differential scanning calorimetry and infrared spectroscopy. It was shown that percenta...

2011
Nicoleta Terinte Roger Ibbett Kurt Christian Schuster

The crystalline structure of cellulose has been studied for a long time. It is well known that crystallinity of cellulose can be measured using quite a number of methods, X-ray diffraction, solid state C CP-MAS NMR, Fourier transforminfrared (FT-IR) spectroscopy and Raman spectroscopy. The solid state C CP-MAS NMR and FT-IR spectroscopy considers contributions from both crystalline and non-crys...

2005
B. Jasińska A. L. Dawidowicz S. Pikus

Three stages of thermal and chemical processing of Vycor glass were carried out. Raw material, the glass with small and big pores was studied. In each stage of study various crystallinity degrees of investigated material were obtained. The relation between crystallinity degree and the intensity of o-Ps components was determined. In nonporous material a high correlation between o-Ps intensity an...

2001
Todd A. Surovell Mary C. Stiner

Three experiments demonstrate that infra-red spectroscopic measures of bone mineral crystallinity are partially dependent upon sample preparation methods. Intensive grinding of bone samples for Fourier transform infra-red (FTIR) spectroscopic analysis results in a net decrease in splitting factor (SF), a common measure of apatite crystallinity. If grinding is overly intensive, SF measurement ma...

2006
C. P. Dullemond

We present a new perspective on the crystallinity of dust in protoplanetary disks. The dominant crystallization by thermal annealing happens in the very early phases of disk formation and evolution. Both the disk properties and the level of crystallinity are thereby directly linked to the properties of the molecular cloud core from which the star+disk system was formed. We show that, under the ...

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