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861.
Ken-ichi Tanaka Masashi Shou Hongbin Zhang Youzhu Yuan Tokio Hagiwara Atsushi Fukuoka Junji Nakamura Daling Lu 《Catalysis Letters》2008,126(1-2):89-95
Pt catalyst supported on carbon nano-tube (CNT) was extremely active for the selective oxidation of CO in H2 at room temperature, which was remarked contrast to the Pt supported on an active carbon (Vulcan carbon) and a graphite powder. Complete oxidation of CO was attained on a 5 wt.% Pt/CNT catalyst (0.8 g) at ca. 40 °C when the O2/CO ratio in a flow of H2 (20 mL/min) + CO (3.0 mL/min) + O2 + N2 was adjusted to be larger than 0.75 at the total flow rate of 100 mL/min. Specific activity of the Pt/CNT catalyst was explained by efficient provision of reactant molecules diffusing on CNT surface to Pt particles. 相似文献
862.
Isshu Sato Yoshitaka Ichikawa Junji Sakanoue Mamoru Mizutani Nobuyasu Adachi Toshitaka Ota 《Journal of the American Ceramic Society》2008,91(2):607-610
A ceramic composite mimicking the pervasively cracked microstructure of flexible sandstone (itacolumite) was successfully synthesized by sintering two ceramic materials with different thermal expansion coefficients. A combination of granular KZr2 (PO4 )3 (high thermal expansion) and powdered KAlSi2 O6 (low thermal expansion) resulted in a material with a jigsaw-like three-dimensional cracking microstructure similar to that of itacolumite. The synthesized composite was found to exhibit ductile deformation. 相似文献
863.
The synthesis of ZrW2O8 from different kinds of mixtures containing ZrO2–WO3, ZrO(NO3)2·2H2O–WO3, ZrCl2O·8H2O–WO3, and ZrO2–(NH4)10W12O41·5H2O was investigated, and the kinetics was analyzed using JMA equation. It was found that ZrO(NO3)2·2H2O, ZrCl2O·8H2O H2O and (NH4)10W12O41·5H2O that were used as inorganic precursors formed ZrO2 and WO3 after firing above 500 °C. The content of ZrW2O8 obtained by firing the mixtures is influenced by the kinds of precursors as well as mixing methods. The formation rate of ZrW2O8 depends on homogeneity related to mixing methods as well as the particle size of starting powders. Phase-pure ZrW2O8 is obtained from the ZrCl2O·8H2O–WO3 mixtures at 1200 °C for 4 h, which is much shorter time than in the case of conventional ZrO2–WO3 mixtures. In the reaction kinetics of ZrO2–WO3 system, the Avrami exponent (n) is ∼0.5 above 1175 °C, indicating that the reaction is controlled by the diffusion-controlled reaction. 相似文献
864.
Kobayashi D Tamai I Sai Y Yoshida K Wakayama T Kido Y Nezu J Iseki S Tsuji A 《Reproduction (Cambridge, England)》2007,134(5):651-658
Carnitine and acetylcarnitine are important for the acquisition of motility and maturation of spermatozoa in the epididymis. In this study, we examined the involvement of carnitine/organic cation transporter (OCTN) in carnitine and acetylcarnitine transport in epididymal spermatozoa of mice. Uptake of both compounds by epididymal spermatozoa was time-dependent and partially Na(+)-dependent. Kinetic analyses revealed the presence of a high-affinity transport system in the spermatozoa, with K(m) values of 23.6 and 6.57 muM for carnitine and acetylcarnitine respectively in the presence of Na(+). Expression of OCTN2 and OCTN3 in epididymal spermatozoa was confirmed by immunofluorescence analysis. The involvement of these two transporters in carnitine and acetylcarnitine transport was supported by a selective inhibition study. We conclude that both Na(+)-dependent and -independent carnitine transporters, OCTN2 and OCTN3, mediate the supply of carnitine and acetylcarnitine to epididymal spermatozoa in mice. 相似文献
865.
许多城市开展了地下管线普查,但普查管理方法却不尽相同。本文基于笔者从项目调研到项目竣工验收全过程参与绍兴市地下管线普查建设与管理的经验,从不同的角度介绍了绍兴市管线普查管理与项目运作过程,重点阐述了管线普查的质量管理及项目管理的特色,希望对其他城市地下管线普查有所借鉴。 相似文献
866.
Shiojiri K Ozawa R Matsui K Kishimoto K Kugimiya S Takabayashi J 《Journal of chemical ecology》2006,32(5):969-979
To elucidate the role of the plant lipoxygenase (LOX)/lyase pathway for host search behavior of two parasitic wasps attacking herbivorous larvae, an Arabidopsis mutant (all84) was isolated with a mutation somewhere in the LOX/lyase pathway. Detached leaves of the mutant were shown to release less (Z)-3-hexenal, a first green leaf volatile (GLV) product of the LOX/lyase pathway. The braconid larval parasitoids studied, Cotesia glomerata and Cotesia plutella, differ in their ability to discriminate among plant volatiles induced by feeding of lepidopteran hosts and nonhosts: C. plutella only responds to plant volatiles induced by hosts (Plutella larvae), whereas the response by the more generalist C. glomerata is not host specific. The Arabidopsis mutant all84 infested by Pieris larvae was less attractive to C. glomerata than Arabidopsis wild type (wt) infested by the host larvae. C. glomerata was attracted by two of the GLV biosynthesized through the LOX/lyase pathway, (E)-2-hexenal and (Z)-3-hexenyl acetate. However, attraction of C. plutellae to volatiles from Plutella-infested all84 plants did not differ from attraction to host-infested wt Arabidopsis. Both wasp species were arrested to the respective host-infested edge of the wt leaf by showing characteristic antennal searching behavior on the edge. In C. glomerata, the duration of this searching behavior at the infested leaf edge was significantly shorter on all84 plants than on wt plants. By contrast, the duration of the searching behavior of C. plutellae on the host-infested leaf edge of all84 was not significantly different from that on the wt leaf. These data suggest that the LOX/lyase pathway is directly involved in the production of attractants and arrestants important for host search behavior of the more generalist C. glomerata, but not for the specialist C. plutellae. 相似文献
867.
Forced convection boiling of subcooled water was performed in a horizontal rectangular channel with the heated surface on the bottom. The experiment was conducted for heating surfaces, 10, 20, or 40 mm in length. Microbubble emission boiling (MEB) was observed in subcooled transition boiling and was easy to generate for the shorter heating surfaces. In higher flow velocity of subcooled water, MEB was generated at even lower subcooling. Stormy MEB was observed at both the higher subcooling and the higher flow velocity of water. In the stormy MEB, the heat flux rose rapidly above the critical heat flux with larger acoustic noise and vibration. © 2001 Scripta Technica, Heat Trans Asian Res, 30(5): 426–438, 2001 相似文献
868.
In this paper, we describe a method for automatically retrieving collocations from large text corpora. This method comprises the following stages: (1) extracting strings of characters as units of collocations, and (2) extracting recurrent combinations of strings as collocations. Through this method, various types of domain-specific collocations can be retrieved simultaneously. This method is practical because it uses plain text with no specific-language-dependent information, such as lexical knowledge and parts of speech. Experimental results using English and Japanese text corpora show that the method is equally applicable to both languages. 相似文献
869.
介绍了长沙市房地产管理局Internet网络系统的设计与实现,着重探讨了建立Intranet网络系统的过程中应考虑的各种因素,对网络的规划设计和系统软,硬件的选择做了比较详细的介绍。 相似文献
870.
本文设计了一种可调的叠式钐钴永磁迥路。用三层径向磁化的钐钴磁体和软铁类磁导材料,借助于计算机,设计了沿轴向长2.0mm,磁场强度1.2kGs,波动0.7%的均匀磁场,为高功率微波管的永磁聚焦系统提供了一种优良的永磁迴路。 相似文献