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91.
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93.
For the well-known British occupational mobility data describing the cross-classification of father’s and son’s occupational status categories, the quasi-uniform association (QU) model considered by Goodman (1979a, 1981b) fits well. This paper gives decompositions for the QU model and also shows that for the British data one of the decomposed models is preferable to the QU model though the QU model has a good fit.
相似文献94.
The oxidations of 1-butene, butadiene, and acetic acid in a large excess of air were carried out over various MoP oxide catalysts with different P2O5 contents and at different calcination temperatures. The oxidation activities were compared with the dehydration activity for isopropyl alcohol, which was used as a measure of the acidity of the catalysts. The acidity of the catalysts increases with an increase in the P2O5 content and attains a maximum at about . With a further increase in P2O5, it decreases. P2O5 alone is completely inactive as a catalyst in the reactions. The acidity drops markedly with an increase in the calcination temperature. A good linear relationship is obtained between the dehydration activity and the oxidation activity for butene and butadiene, as well as the isomerization activity for butene. The activity per unit surface area for the oxidation of acetic acid is not affected by the P2O5 content. The results are discussed from the viewpoint of the acid-base nature of the reactants and the catalyst. 相似文献
95.
96.
Sadao Sato Yukio Sakata Joh Aoki Kazuhisa Kubota 《Polymer Engineering and Science》2006,46(10):1387-1393
A probe consisting of a cartridge heater was inserted into melted polypropylene composites (PP/mica = 5, 10, and 20 wt%) flowing in a die having a diameter of 10 mm, and the effects of mica on the heat transfer coefficient and the heat transfer behavior from the surface of the probe to the flow compound material were examined experimentally. As a result, the heat transfer coefficient of the PP/mica composites increases 15–20% depending on the flow velocity and filler content. In general, the Prandtl number (Pr) for high‐viscosity (η) melted polymer is greater than one (Pr > 1), and the Prandtl number for polypropylene composites increases as the viscosity increases and decreases depending on the flow velocity and the temperature. The relationship between Pr and η is directly proportional, and the β value, which is given by the slope of the Pr ? η diagram, is a constant that shows the viscosity dependency of the Prandtl number. The β value can be determined by the ratio of the specific heat to the thermal conductivity. The Nusselt number depends on the mica content of the filler and increases gradually. POLYM. ENG. SCI. 46:1387–1393, 2006. © 2006 Society of Plastics Engineers 相似文献
97.
Trees of the genus Glochidion (Phyllanthaceae) are pollinated by females of Epicephala moths (Gracillariidae) whose larvae consume the seeds of the flowers that they pollinate. Each Epicephala moth species is specific locally to a single host species, although two to four Glochidion hosts often cooccur. To investigate the role of olfactory signals in maintaining the plant−moth specificity, we analyzed
floral scent composition of five Glochidion species by using gas chromatography–mass spectrometry (GC-MS) and conducted Y-tube olfactometer bioassays with Epicephala moths and their host flowers. The GC-MS analysis showed that the floral scents of the five Glochidion species are dominated by (R)-(−)- and (S)-(+)-linalool, and (E)- and (Z)-β-ocimene, and that each species produces 6–20 compounds. Transformation of scent profiles by using chord-normalized expected
species shared distances and analysis of the data with nonmetric multidimensional scaling showed that floral volatiles of
cooccurring Glochidion species can be distinguished by relative chemical composition, especially that of minor compounds. The bioassay with pollinators
of Glochidion lanceolatum and Glochidion ruburm further indicated that Epicephala moths are capable of discriminating their hosts by using floral odor. The results suggest that the floral scent of Glochidion is one of the important key signals that mediate the encounters of the species-specific partners in the Glochidion–Epicephala mutualism. 相似文献
98.
Yuji Shimada Akio Sugihara Hirofumi Nakano Tomomi Yokota Toshihiro Nagao Sadao Komemushi Yoshio Tominaga 《Journal of the American Oil Chemists' Society》1996,73(11):1415-1420
An attempt was made to produce structured lipids containing essential fatty acid by acidolysis with 1,3-positional specificRhizopus delemar lipase. The lipase was immobilized on a ceramic carrier by coprecipitation with acetone and then was activated by shaking
for 2 d at 30°C in a mixture of 5 g safflower or linseed oil, 10 g caprylic acid, 0.3 g water and 0.6 g of the immobilized
enzyme. The activated enzyme was transferred into the same amount of oil/caprylic acid mixture without water, and the mixture
was shaken under the same conditions as for the activation. By this reaction, 45–50 mol% of the fatty acids in oils were exchanged
for caprylic acid, and the immobilized enzyme could be reused 45 and 55 times for safflower and linseed oils, respectively,
without any significant loss of activity. The triglycerides were extracted withn-hexane after the acidolysis and then were allowed to react again with caprylic acid under the same conditions as mentioned
above. When acidolysis was repeated three times with safflower oil as a starting material, the only products obtained were
1,3-capryloyl-2-linoleoylglycerol and 1,3-capryloyl-2-oleoyl-glycerol, with a ratio of 86∶14 (w/w). Equally, the products
from linseed oil were 1,3-capryloyl-2-α-linolenoyl-glycerol, 1,3-caprylol-2-linoleoyl-glycerol, and 1,3-capryloyl-2-oleoly-glycerol
(60∶22∶18, w/w/w). All fatty acids at the 1,3-positions in the original oils were exchanged for caprylic acid by the repeated
acidolyses, and the positional specificity ofRhizopus lipase was also confirmed to be strict. 相似文献
99.
Yasunari Ishikawa Seiji Kuroda Jin Kawakita Matsufumi Takaya 《Surface & coatings technology》2007,201(8):4718-4727
WC-20 mass%Cr3C2-7 mass%Ni powder was sprayed onto low-carbon steel substrates by a commercial high velocity oxygen-fuel (HVOF) spray process as well as by an improved HVOF process equipped with a gas shroud attachment. The latter process utilizes a nitrogen gas flow to shield the region between the spray gun and the substrate in order to suppress the material's degradation caused by reaction with air such as oxidation and decarburization. Some coatings were further heat-treated in air at 773 K for 30 h to form a thin oxide film on the surface. The sliding wear properties of these coatings against an iron pin were evaluated by using a pin-on-disk wear tester. The specific wear rate of the as-sprayed cermet coatings prepared under the conventional spray condition was about three times higher than that of the chrome plating but by using the gas shroud, the wear rate was reduced to the same level with the chrome plating. The specific wear rate could be further decreased by the oxidation heat-treatment. It was found that a proper amount of oxides existing on the surface or within the coatings have a great beneficial effects on the wear properties such as to promote the transition from severe wear to mild wear and thus to reduce the wear rate remarkably. XPS analysis of the transfer particles collected from the wear track revealed a shift in the oxidation state of iron depending on the wear condition. 相似文献
100.
Makoto Takahashi Toshiyuki Miyauchi Kengo Sawada Hiroyuki Ishikawa Shoji Sato Masahiro Tahashi Koichi Wakita Sadao Ohkido Motohisa Honda Asami Murai Masato Kamiya Masanori Matubara 《Journal of the American Ceramic Society》2009,92(3):578-584
The preparation of large-scale YBa2 Cu3 O7− x superconductor samples was investigated. This method is based on plastic forming using a slurry consisting of YBa2 Cu3 O7− x particles and a sol solution made up of multimetallic hydroxide particles (YBa2 Cu3 (OH) x colloidal particles) and poly(vinyl) alcohol (PVA). The effects of adding PVA on the product, the crystallinity, and the superconducting properties of the sample were investigated. It was found that PVA acted as a protective colloid in the sol solution and stabilized YBa2 Cu3 (OH) x colloidal particles, and that the role of PVA changed from a thickener to a flocculant during drying so that the formability/workability of the green sheet sample was improved and large samples (about 80 mm × 80 mm × 3 mm) without large cracks were obtained after firing. The samples became superconducting at 91.5±0.5 K ( T con ) and the full transition temperature ( T coff ) was 88.5±1.5 K. The critical current density ( J c ) of the sample prepared from the slurry containing 1 wt% PVA was 713±150 A/cm2 at 77 K. This J c value was improved to 2300 A/cm2 by heat treatment at 773 K under an oxygen atmosphere. 相似文献