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排序方式: 共有393条查询结果,搜索用时 359 毫秒
91.
92.
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
93.
94.
Tomoji Osada Keiji Sonoya Takeyuki Abe Masanobu Nakamura Shuko Goto Saki Otagiri 《Welding International》2013,27(8):535-541
ABSTRACTThe needs of aluminium joints have grown in recent years. However, as aluminium forms strong oxide layers on the surface in an atmosphere, joining of these materials is difficult. This is why we conceived a new atmosphere solid-phase bonding method that uses high-frequency induction heating and ultrasonic vibration. The effects of ultrasonic vibration and bonding conditions on this new bonding method were investigated. As a result, we were able to confirm the efficacy of ultrasonic waves on bonding. The bonding mechanism of new bonding method was also clear. 相似文献
95.
Osada K. Jinuk Luke Shin Khan M. Liou Y. Wang K. Shoji K. Kuroda K. Ikeda S. Ishibashi K. 《Solid-State Circuits, IEEE Journal of》2001,36(11):1738-1744
A universal-Vdd 32-kB four-way-set-associative embedded cache has been developed. A test cache chip was fabricated by using 0.18-μm enhanced CMOS technology, and it was found to continuously operate from 0.65 to 2.0 V. Its operating frequency and power are from 120 MHz and 1.7 mW at 0.65 V to 1.04 GHz and 530 mW at 2.0 V. The cache is based on two new circuit techniques: a voltage-adapted timing-generation scheme with plural dummy cells for the wider voltage-range operation, and use of a lithographically symmetrical cell for lower voltage operation 相似文献
96.
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
97.
Kotabe A. Osada K. Kitai N. Fujioka M. Kamohara S. Moniwa M. Morita S. Saitoh Y. 《Solid-State Circuits, IEEE Journal of》2005,40(4):870-876
To realize high-density SRAMs, we developed a four-transistor SRAM cell with a newly developed stacked vertical poly-silicon PMOS. The vertical poly-silicon PMOS has a gate surrounding a body that forms a channel and yields a drive current of 20 /spl mu/A at 25/spl deg/C. Vertical poly-silicon PMOSs are used as transfer MOSs and are stacked over the bulk NMOSs, used as driver MOSs, to reduce the size of a four-transistor SRAM cell. As a result, the size of the proposed four-transistor SRAM cell was 38% of that of a six-transistor SRAM cell. We also developed an electric-field-relaxation scheme to reduce cell leakage and a dual-word-voltage scheme to improve cell stability. By applying these two schemes to the proposed four-transistor SRAM cell, we achieved a 90% reduction in cell leakage and an improvement in cell stability. 相似文献
98.
99.
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
100.
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