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排序方式: 共有191条查询结果,搜索用时 15 毫秒
41.
Yoshiyuki Sato Ming Wang Shigeki Takishima Hirokatsu Masuoka Taku Watanabe Yoshihito Fukasawa 《Polymer Engineering and Science》2004,44(11):2083-2089
The solubility of butane and isobutane in molten polypropylene (PP) and polystyrene (PS) was measured at pressures up to 3 MPa and along four isotherms from 438 to 483 K for PP and from 348 to 473 K for PS. The solubility increased with increasing pressure and decreasing temperature. At 438 K and 2 MPa, the solubilities of butane and isobutane in PP were 0.15 and 0.11 g‐gas/g‐polym, respectively. At 423 K and 2 MPa, the solubilities of butane and isobutane in PS were 0.08 and 0.05 g‐gas/g‐polym, respectively. Solubility could be correlated with the Sanchez‐Lacombe equation of state with temperature‐dependent binary interaction parameters to within 4.4% average relative deviation. Henry's constant for these gases in the PP and PS obtained in this work were used to determine correlation equations along with literature data. Polym. Eng. Sci. 44:2083–2089, 2004. © 2004 Society of Plastics Engineers. 相似文献
42.
Anhydrides production is newly proposed as an additional pyrolysis mechanism of a biopolymer, poly(3‐hydroxybutyrate) (PHB). In spite of many suggestions of multiple degradation mechanisms, simple random chain scission by β‐elimination has been accepted as an exclusive mechanism of the thermal degradation of PHB. However, a wide range of activation energy value of the degradation and the deviation from the random chain scission statistics have suggested the presence of other kinds of mechanism out of the random scission. To confirm other mechanisms out of the random scission, minor pyrolyzates from PHB were characterized with 1H/13C‐NMR, Fourier transform infrared spectroscopy, and fast atom bombardment mass spectrometry. As a result, crotonic anhydride and its oligomers were detected as minor products from condensation reactions between carboxyl groups. The anhydrides production must be one reaction out of the conforming process to the random degradation statistics and contribute to the complexity of PHB pyrolysis. An expected thermal degradation pathway of PHB was proposed. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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Shinya Kano Yoshihito Matsumura Hirohisa Uchida T. Kuji 《Microgravity science and technology》2005,17(3):82-86
In this paper, we investigated the possibility of preparation of TbFe2 giant magnetostrictive alloys under a microgravity condition using 6 m drop-tube system on basis of a feasibility study by
JAMIC drop-tower. The diameters of TbFe2 alloy droplets varied from 1.1 to 2.1 mm were obtained. The magnetostriction of 1.1 mm droplet shows the highest value of
about 1600 ppm at external magnetic field of 15 kOe. The magnetostriction of TbFe2 droplets increased with decreasing diameter. It was suggested that a cooling rate during free-fall in helium gas atmosphere
and oil quenching influenced the magnetostriction of the samples. We concluded that 6 m drop-tube system could be potential
the continuous preparation process for high performance TbFe2 giant magnetostrictive alloys. 相似文献
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AbstractSettlement–time behaviors in the last stage of consolidation are studied both in the laboratory and in the field. It is shown that the long-term settlement–time curves observed in the field are linear with the logarithm of time and the rate of the long-term settlement are analogous to the rate of secondary compression measured in a laboratory. The finite difference consolidation analyses for cohesive soils exhibiting large amounts of secondary compression during primary consolidation provide fairly good predictions of the settlement–time curves observed in the laboratory and in the field. In this paper, the applicability of the secondary compression model established in the laboratory is examined in in situ conditions. The initial rate of secondary compression used in this paper has a predominant influence on the settlement–time curve with different drainage distances. It is emphasized that the assumption for unknown secondary compression behaviors during the primary consolidation has a predominant influence on the settlement–time curve. 相似文献
48.
GluN2B‐Selective N‐Methyl‐d‐aspartate (NMDA) Receptor Antagonists Derived from 3‐Benzazepines: Synthesis and Pharmacological Evaluation of Benzo[7]annulen‐7‐amines
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Dr. Andre Benner Alessandro Bonifazi Chikako Shirataki Louisa Temme Dr. Dirk Schepmann Prof. Wilma Quaglia Prof. Osami Shoji Prof. Yoshihito Watanabe Dr. Constantin Daniliuc Prof. Dr. Bernhard Wünsch 《ChemMedChem》2014,9(4):741-751
Given their high neuroprotective potential, ligands that block GluN2B‐containing N‐methyl‐D ‐aspartate (NMDA) receptors by interacting with the ifenprodil binding site located on the GluN2B subunit are of great interest for the treatment of various neuronal disorders. In this study, a novel class of GluN2B‐selective NMDA receptor antagonists with the benzo[7]annulene scaffold was prepared and pharmacologically evaluated. The key intermediate, N‐(2‐methoxy‐5‐oxo‐6,7,8,9‐tetrahydro‐5H‐benzo[7]annulen‐7‐yl)acetamide ( 11 ), was obtained by cyclization of 3‐acetamido‐5‐(3‐methoxyphenyl)pentanoic acid ( 10 b ). The final reaction steps comprise hydrolysis of the amide, reduction of the ketone, and reductive alkylation, leading to cis‐ and trans‐configured 7‐(ω‐phenylalkylamino)benzo[7]annulen‐5‐ols. High GluN2B affinity was observed with cis‐configured γ‐amino alcohols substituted with a 3‐phenylpropyl moiety at the amino group. Removal of the benzylic hydroxy moiety led to the most potent GluN2B antagonists of this series: 2‐methoxy‐N‐(3‐phenylpropyl)‐6,7,8,9‐tetrahydro‐5H‐benzo[7]annulen‐7‐amine ( 20 a , Ki=10 nM ) and 2‐methoxy‐N‐methyl‐N‐(3‐phenylpropyl)‐6,7,8,9‐tetrahydro‐5H‐benzo[7]annulen‐7‐amine ( 23 a , Ki=7.9 nM ). The selectivity over related receptors (phencyclidine binding site of the NMDA receptor, σ1 and σ2 receptors) was recorded. In a functional assay measuring the cytoprotective activity of the benzo[7]annulenamines, all tested compounds showed potent NMDA receptor antagonistic activity. Cytotoxicity induced via GluN2A subunit‐containing NMDA receptors was not inhibited by the new ligands. 相似文献
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In the search for new fluorescent materials among lanthanoid-activated Ca2 SnO4 compounds, a parallel solution-based synthesis approach was applied and a new blue-emission Ca2 SnO4 :Ce phosphor was discovered; its emission intensity reaches 80% of the intensity of one of the best commercial Y3 Al5 O12 :Ce3+ phosphors. Among 14 lanthanoid-activated materials, three categories could be distinguished with respect to the effect of the dopant ion on the excitation and emission properties of the phosphor. In addition, potential phosphors in the A–Sn–O (A=Mg, Ca, Sr, and Ba) systems were investigated and Ca2 SnO4 was found to be the most suitable host compound for the lanthanoid-activated phosphors. 相似文献