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981.
R.E. Lobnig W. Villalba K. Goll J. Vogelsang I. Winkels R. Schmidt P. Zanger J. Soetemann 《Progress in Organic Coatings》2006,55(4):363-374
The critical pigment–volume–concentration (CPVC) of a solvent-based epoxy coating with various pigment–volume–concentrations (PVC) was analyzed. It was shown that electrochemical impedance spectroscopy (EIS) is a suitable method to detect the CPVC of coatings. The CPVC can be derived from EIS Bode plots or by fitting the EIS-curves using simple equivalent circuit diagrams. The parameters pore resistance RP, capacitance C of the constant phase element (CPE), the relative dielectric constant R derived from C, and the exponent n of the CPE allow the determination of the CPVC. 相似文献
982.
983.
H. E. Schmidt 《European Journal of Lipid Science and Technology》1967,69(12):913-916
Determination of Tocopherols in Oils and Fats: Influence of the Tocopherol Content of Ground-nut and Soybean Oils on the Course of Oxidation of these Oils on Heating I A sensitive method for the quantitative determination of α, γ and δ tocopherols in edible oils and fats was worked out. The tocopherols are isolated from unsaponifiable matter by thinlayer chromatography and ultimately each of them was determined photometrically from the red colour formed with iron chloride and bathophenanthroline. The effect of reduction in tocopherol content, resulting from the heating of oils, on the course of the oxidation of oil was followed, among others, with the help of 4-hexylresorcin. The blue dyestuff formed by this reaction was synthesized and identified as trimethin dye. 相似文献
984.
Ohne Zusammenfassung
VDI 相似文献
985.
We have studied the adiabatic and autothermal oxidative coupling of methane over Pt on -Al2O3 monoliths at space velocities above 105 h-1. The selectivity to C2 hydrocarbons (primarily acetylene) reaches a maximum of around 20% at low fuel to oxygen ratios, low dilution, and high space velocities. These conditions promote a large temperature gradient in the monolith, with an exit temperature of nearly 1500°C and an entrance temperature of less than 200°C. This temperature gradient appears to be the driving force for C2 hydrocarbon formation under these conditions. Both homogeneous and heterogeneous reactions may be involved in producing coupling products, and a combustion model predicts C2 selectivities similar to those observed. 相似文献
986.
O. Klüsener H. W. Hahnemann H. Gebelein H. Brauer H. Petermann K. Gersten G. Franke K. Meerbeck E. Becker Ommo Schmidt R. Jaeckel H. Peeken 《Forschung im Ingenieurwesen》1963,29(3):89-92
Ohne Zusammenfassung
VDI 相似文献
987.
This study was designed to measure the effect of dietary n−3 fatty acids (FA) on platelets and blood lipids. Healthy men (n=9),
ages 31 to 65, were fed diets in which salmon was the source of n−3 fatty acids. They were confined in a nutrition suite at
this Center for 100 days. Food intake and exercise levels were rigidly controlled. Initially they were placed on a stabilization
diet for 20 days, then six men were fed the salmon diet for 40 days. The others remained on the stabilization diet. The two
groups switched diets for the last 40 days of the study. Both diets were isocaloric [16% protein, 54% carbohydrate, and 30%
fat by energy-% (En%)]. The salmon diet contained 7.5% of calories from n−6 FA and 2% from n−3 FA, primarily eicosapentaenoic
acid (EPA) and docosahexaenoic acid (DHA) in a 40∶60 ratio, while the stabilization diet contained 7.5% of calories from n−6
FA and less than 0.3% n−3 FA, mainly 18∶3n−3. The bleeding time was unaffected by the diets in this study. The prothrombin
time was shortened (11.6 sec.vs. 12.6 sec., p<0.01) for the subjects consuming the salmon diet as compared to that measured after 20 days of the stabilization
diet. Mean platelet volume increased significantly during the period in which the volunteers consumed the salmon diet compared
to the baseline diet (p<0.01), while the mean platelet levels decreased. Platelet aggregation (PA) was measured in platelet
rich plasma before, during, and after the salmon diet using collagen, ADP, arachidonic acid (AA), and thrombin agonists. The
PA threshold for ADP was significantly increased for the subjects on the salmon diet (p<0.05). No change in the PA threshold
was detected for collagen or thrombin. The PA threshold for AA was unchanged also, but the platelets in subjects consuming
the salmon diet had a prolonged time to maximum aggregation (p<0.01) with this reagent compared to platelets from men on the
stabilization diet. Plasma, red cell, and platelet total FA composition was determined by capillary GLC. While the men consumed
the salmon diets, there were marked increases (3 to 10-fold) in the EPA and DHA levels in all blood components with concomitant
decreases in linoleic acid and AA levels. Thus, a salmon diet, high in n−3 FA, did not influence the bleeding times, but it
decreased the sensitivity of platelets to ADP and AA, increased the mean platelet size, decreased the platelet count, and
changed the FA composition of the plasma, RBC and platelet membrane lipids. 相似文献
988.
We present the setup of a variable-angle vector-magneto-optical generalized ellipsometer (VMOGE) in the spectral range from 300 to 1100 nm using an octupole magnet, and demonstrate VMOGE measurements of the upper 3 × 4 submatrix of the Mueller matrix in a magnetic field of arbitrary orientation and magnitude up to 0.4 T at room temperature. New "field orbit" measurements can be performed without physically moving the sample, which is useful to study magnetic multilayer or nanostructure samples. A 4 × 4 matrix formalism is employed to model the experimental VMOGE data. Searching the best match model between experimental and calculated VMOGE data, the magneto-optical dielectric tensor ?(MO) of each layer in a multilayer sample system can be determined. In this work, we assume that the nonsymmetric terms of ?(MO) are induced by an external magnetic field and depend linearly on the sample magnetization. Comparison with vector magnetometer measurements can provide the anisotropic magneto-optical coupling constants Q(x), Q(y), Q(z). 相似文献
989.
Kienberger F Stroh C Kada G Moser R Baumgartner W Pastushenko V Rankl C Schmidt U Müller H Orlova E LeGrimellec C Drenckhahn D Blaas D Hinterdorfer P 《Ultramicroscopy》2003,97(1-4):229-237
We employed magnetic ACmode atomic force microscopy (MACmode AFM) as a novel dynamic force microscopy method to image surfaces of biological membranes in their native environments. The lateral resolution achieved under optimized imaging conditions was in the nanometer range, even when the sample was only weakly attached to the support. Purple membranes (PM) from Halobacterium salinarum were used as a test standard for topographical imaging. The hexagonal arrangement of the bacteriorhodopsin trimers on the cytoplasmic side of PM was resolved with 1.5nm lateral accuracy, a resolution similar to images obtained in contact and tapping-mode AFM. Human rhinovirus 2 (HRV2) particles were attached to mica surfaces via nonspecific interactions. The capsid structure and 2nm sized protein loops of HRV2 were routinely obtained without any displacement of the virus. Globular and filamentous structures on living and fixed endothelial cells were observed with a resolution of 5-20nm. These examples show that MACmode AFM is a favorable method in studying the topography of soft and weakly attached biological samples with high resolution under physiological conditions. 相似文献
990.
Croizé L Mondelain D Camy-Peyret C Delmotte M Schmidt M 《The Review of scientific instruments》2008,79(4):043101
We have developed a tunable diode laser spectrometer, called SIMCO (spectrometer for isotopic measurements of CO(2)), for determining the concentrations of (12)CO(2) and (13)CO(2) in atmospheric air, from which the total concentration of CO(2) and the isotopic composition (expressed in delta units) delta(13)CO(2) are calculated. The two concentrations are measured using a pair of lines around 2290.1 cm(-1), by fitting a line profile model, taking into account the confinement narrowing effect to achieve a better accuracy. Using the Allan variance, we have demonstrated (for an integration time of 25 s) a precision of 0.1 ppmv for the total CO(2) concentration and of 0.3[per thousand] for delta(13)CO(2). The performances on atmospheric air have been tested during a 3 days campaign by comparing the SIMCO instrument with a gas chromatograph (GC) for the measurement of the total CO(2) concentration and with an isotopic ratio mass spectrometer (MS) for the isotopic composition. The CO(2) concentration measurements of SIMCO are in very good agreement with the GC data with a mean difference of Delta(CO(2))=0.16+/-1.20 ppmv for a comparison period of 45 h and the linearity of the concentration between the two instruments is also very good (slope of correlation: 0.9996+/-0.0003) over the range between 380 and 415 ppmv. For delta(13)CO(2), the comparison with the MS data shows a larger mean difference of Delta(delta(13)CO(2))=(-1.9+/-1.2)[per thousand], which could be partly related to small residual fluctuations of the overall SIMCO instrument response. 相似文献