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971.
Since the most important characteristic of optical glass is the uniformity of its refractive index, which is itself a function of fictive temperature, any fine annealing treatment must be such as to bring about substantial uniformity in fictive temperature. Methods of accomplishing this are reviewed. In terms of total required time in the annealing process, the most efficient method consists of soaking the glass for a short time at a temperature near the annealing point and cooling at a constant rate to a temperature below the annealing range and at an increased rate to room temperature. Formulas are given for specifying the parameters in the annealing schedule in terms of the final condition of the glass as to stress and index. The several outstanding advantages of this method of annealing are discussed. 相似文献
972.
A method is presented to identify flow model parameters from radioactive signals with a high noise content. The method is based on the two detection points method with a highly accurate identification of the parameters by optimization in the frequency domain. The study of dispersed phase of a pulsed column with perforated plate using this method has shown evidence that there are operating conditions for which the piston-diffusion flow does not describe well the behavior of the dispersed phase. 相似文献
973.
Potentiometric titration of long chain quaternary ammonium compounds using sodium tetraphenyl borate
C. N. Wang L. D. Metcalfe J. J. Donkerbroek A. H. M. Cosijn 《Journal of the American Oil Chemists' Society》1989,66(12):1831-1833
Current methods for determining the activity of long chain quaternary ammonium compounds (QACS) are based either on dye partition,
titration, or colorimetric analysis. The two major disadvantages of these methods are the disparity of partition coefficients
among differently constituted QACS and the difficulty in detecting visual end points. Some potentiometric titration methods
for QACS have been reported in the literature. However, back titration techniques, as well as complicated electrode systems,
are generally involved.
A new potentiometric titration system is presented which uses aqueous sodium tetraphenylborate (TPB) solution as a titrant
and a platinum-platinum electrode system to detect the end point. Standard potentiometric titration instruments may be used
for this method. This new potentiometric method is superior in precision and accuracy to visual (colorimetric) methods.
Original version presented at the 1986 Annual AOCS Meeting in Honolulu, HI. 相似文献
974.
H. Bertsch H. Reinheckel G. Czichocki 《European Journal of Lipid Science and Technology》1966,68(12):1002-1009
Preparation and Sulfation of N-Substituted 12-Hydroxy-octadecan-(9) Acid-(1) Amides Ricinoleic acid amides, substituted at the nitrogen atom, were converted to the sodium salts of the monosulfuric acid esters of the substituted ricinoleic acid amides (sodium salt of substituted 12-hydroxy sulfonyl-oxy-oleic acid amide) by sulfation with chlorosulfuric acid-diethyl ester-adduct followed by neutralisation. Washing capacity as well as surface tension, angle of contact and wetting capacity in relation to the concentration of the aqueous solutions of these anion active surfactants are measured. 相似文献
975.
F. Molaparast-Saless E. Shrago T. L. Spennetta S. Donatello L. M. Kneeland S. H. Nellis A. J. Liedtke 《Lipids》1988,23(5):490-492
A method has been developed for determination of individual long-chain fatty acyl-CoA esters from heart and skeletal muscle
using high performance liquid chromatography (HPLC). The esters were extracted from freezeclamped tissue of pig and rat hearts
and rat skeletal muscle for analysis on a radially compressed C18 5μ reversephase column. Nine peaks in the extract with carbon chain lengths from C12 to C20 that subsequently disappeared on alkaline hydrolysis were identified. The major acyl-CoA peaks were 14∶1, 18∶2, 16∶0 and
18∶1 and additionally in rat heart 18∶0. Total long-chain acyl-CoA esters obtained by summation of the individual molecular
species was 11.34±1.48 nmol/g wet wt. pig heart; 14.51±2.11 nmol/g wet wt. in rat heart, and 4.35±0.71 nmol/g wet wt. in rat
skeletal muscle. These values were approximately 132% of those obtained using a separate procedure that measured total CoA
by HPLC after alkaline hydrolysis of the esters. The described method demonstrates the quantitation of individual acyl-CoA
species in muscle tissue. Therefore, it has a number of advantages in that it permits information to be obtained on the individual
molecular species under various nutritional and metabolic conditions. 相似文献
976.
Mechanical properties of high density polyethylene (HDPE) extended to draw ratios in the 20–40 range have been determined and compared with corresponding properties of the polymers containing particulates including rutile, carbon black, iron oxide, and mica. Shrinkage of drawn structures was studied to temperatures near the fusion of the polymer host. The degree of interaction at polymer/additive interfaces was varied by surface coating certain of the solids with standard coupling agents. Solids were found to increase tensile moduli and to decrease shrinkage, particularly at higher exposure temperatures. The magnitude of changes due to the presence of solids was shown to depend on the apparent interaction at contacts between host and additive. In a dispersion–force matrix, like HDPE, benefits were optimized when the particulates were amphoteric or neutral, rather than having pronounced acid or base interaction potentials. 相似文献
977.
E. H. Gruger R. W. Nelson M. E. Stansby 《Journal of the American Oil Chemists' Society》1964,41(10):662-667
The fatty acid composition of body lipids was determined by GLC for 14 species of saltwater fish, three species of freshwater
fish and four species of shellfish. In addition, liver lipids of two species and egg lipids of one species were analyzed for
comparison with the fish body lipids. The various species ranged from lean to fatty and contained from 0.7~15.5% oil in the
tissues. Certain major fatty acids were found to vary widely among the species, as follows: 1.6~8.0% myristic, 9.5~33.4% palmitic,
2.0~11.2% palmitoleic, 5.2~29.1% oleic, 0.7~10.5% eicosenoic, 5.0~21.5% eicosapentaenoic, 0.2~11.6% docosenoic and 5.9~26.2%
docosahexaenoic acids. Analyses of two separate mullet-oil samples illustrated the wide differences that are possible for
a single species caught during different seasons. Significant differences in the amt of particular fatty acids were found
in comparing freshwater-fish analyses with analyses for marine fish. Oysters and scallops showed large amt of pentaenoic and
hexaenoic acids in their oils.
Presented in part at the AOCS Meeting, New York, 1960. 相似文献
978.
979.
Smith Robert El. Wekstein David R. Sullivan Robert H. 《IEEE transactions on bio-medical engineering》1970,(2):151-156
A multiplexing, demodulating, and recording telemetry system designed to process multiple pulse-coded temperature channels is described. The system provides complete control of recording and multiplexing sequences and timing, and gives a single analog signal in response to each sample of pulse-coded data. It identifies all channels and indicates to a computer when a new data sample is to be processed. The system is self-calibrating to maintain accuracy over extended data collection periods, and is inexpensive. 相似文献
980.
Using a Debye function analysis, the presence of icosahedral and face centered cuboctahedral gold in a 1 1 ratio has been found in freshly prepared Au/Mg(OH)2 catalyst. The results support earlier studies which suggest the icosahedral form to be more stable at small nanometer sizes. Interactions between the gold and the Mg(OH)2 support appear to be weak, with the gold rapidly coagulating over a period of three months. Re-analysis of the aged sample shows the gold to be mainly in the form of truncated decahedra. 相似文献