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11.
Summary Preparations of soluble TiCl3 catalysts by reduction of TiCl4 with some types of Grignard reagents were carried out in halogenated hydrocarbon solvents by using appropriate ethers as donor. The soluble TiCl3·MgX2·ether complex catalysts and triisobutylaluminum as co-catalyst showed high activities for the copolymerization of ethylene with propylene. It was first found that the soluble TiCl3·MgX2·ether complex catalysts enhance the activities for the copolymerizations in the same manner as solid titanium catalysts supported on MgCl2 which show high activities for homopolymerizations of olefin monomers. The copolymers obtained possessed low crystallinities. Also, the copolymers seem to contain microblock sequences and have outstandingly high tensile strength and elongation at break compared to copolymers by the conventional VOCl3/Al(Et)1.5Cl1.5 catalyst system. 相似文献
12.
Minoru Tsuda Setsuko Oikawa Akira Yokota Mitsuo Yabuta Wataru Kanai Ken-Ichi Kashiwagi Isamu Hijikata Hisashi Nakane 《Polymer Engineering and Science》1983,23(18):993-999
A dry developable negative working resist composition comprised of poly(methyl isopropenyl ketone) (PMIPK) and 4-methyl-2,6-di(4′-azido-benzylidene) cyclohexanone-1 was examined. The main photochemical product formed in the resist pattern was found to be a secondary amine which crosslinks PMIPK. Post-annealing forms a hydrogen-bonded product which shows a powerful electronic excitation energy quenching effect. The quencher is more powerful than the aromatic compound arising from the azide by post-annealing only. The residual resist thickness of the negative pattern is about 80 percent of the initial thickness of the coating in spite of all the azide compound remaining in the resist coating. The obtained dry developed resist pattern has a high dry etch resistance. Etchings of Si and SiO2 were performed by plasma and reactive ion etching, respectively. 相似文献
13.
Kuramochi K Suzuki K Yamazaki T Mitsuishi K Furuya K Hashimoto I Watanabe K 《Ultramicroscopy》2008,109(1):96-103
The structure and composition of the 1/4{110} twin boundary in alpha-Zn7Sb2O12 have been determined by using quantitative high-angle annular dark field scanning transmission electron microscopy (HAADF STEM) analysis. The noise in the experimental HAADF STEM images is reduced by using the maximum entropy method and average processing, and the parameters used in dynamical simulations are experimentally determined. From the analysis, it has been found that octahedral sites in the twin boundary slightly shift parallel to the [110] direction, and a reduction of the Sb concentration at the octahedral sites on the plane adjacent to the twin boundary was detected. The reduction was measured from three regions in the same twin boundary, and the Sb concentrations were 4 +/- 3, 8 +/- 3 and 19 +/-2 at% from 33 at%. 相似文献
14.
This study was designed to test the hypothesis that distinct alterations in cardiac beta-adrenoceptors (betaARs) may occur during cardiopulmonary bypass (CPB) alone, during CPB with cold cardioplegic cardiac arrest (CCCA), and during CPB with electrically induced ventricular fibrillation (EIVF). We assessed the density and affinity of right atrial betaARs in 27 patients undergoing open-heart surgery by (-)-[125I]iodocyanopindolol binding before CPB, defined as the "control," immediately after initiation, defined as "before," and immediately before the cessation of CCCA or EIVF, defined as "after." The density of betaARs was equivalent between the "control" and "before" groups; however, during CPB with EIVF, the density of betaARs decreased significantly (P < 0.001), whereas during CPB with CCCA, it increased significantly (P < 0.01). The rate of changes of the betaAR density was not correlated with the "before"-"after" interval, and the affinity of the betaARs did not change throughout these CPBs. These findings demonstrate that: CPB alone does not affect cardiac betaARs, at least until the onset of EIVF or CCCA; CPB with EIVF induces rapid desensitization of cardiac betaARs; and CPB with CCCA induces rapid sensitization of cardiac betaARs. 相似文献
15.
Kazuto Okazaki Tatsuya Ogiwara Dongshin Yang Kentaro Sakata Ken Saito Yoshifumi Sekine Fumio Uchikoba 《Artificial Life and Robotics》2011,16(2):229-233
This article presents the micro-electro-mechanical systems (MEMS) microrobot which demonstrates locomotion controlled by hardware
neural networks (HNN). The size of the microrobot fabricated by the MEMS technology is 4 × 4 × 3.5 mm. The frame of the robot
is made of silicon wafer, and it is equipped with a rotary-type actuator, a link mechanism, and six legs. The rotary-type
actuator generates rotational movement by applying an electrical current to artificial muscle wires. The locomotion of the
microrobot is obtained by the rotation of the rotary-type actuator. As in a living organism, the HNN realized robot control
without using any software programs, A/D converters, or additional driving circuits. A central pattern generator (CPG) model
was implemented as an HNN system to emulate the locomotion pattern. The MEMS microrobot emulated the locomotion method and
the neural networks of an insect with the rotary-type actuator, the link mechanism, and the HNN. The microrobot performed
forward and backward locomotion, and also changed direction by inputting an external trigger pulse. The locomotion speed was
0.325 mm/s and the step width was 1.3 mm. 相似文献
16.
Yusuke Tsuda Yonghao Yue Yoshinori Dobashi Tomoyuki Nishita 《The Visual computer》2010,26(6-8):883-891
In the field of computer graphics, simulation of fluids, including avalanches, is an important research topic. In this paper, we propose a method to simulate a kind of avalanche, mixed-motion avalanche, which is usually large and travels down the slope fast, often resulting in impressive visual effects. The mixed-motion avalanche consists of snow smokes and liquefied snow which form an upper suspension layer and a lower dense-flow layer, respectively. The mixed-motion avalanche travels down the surface of the snow-covered mountain, which is called accumulated snow layer. We simulate a mixed-motion avalanche taking into account these three snow layers. We simulate the suspension layer using a grid-based approach, the dense-flow and accumulated snow layer using a particle-based approach. An important contribution of our method is an interaction model between these snow layers that enables us to obtain the characteristic motions of avalanches, such as the generation of the snow smoke from the head of the avalanche. 相似文献
17.
The model of self-organized criticality (SOC) is a useful tool to understand the complexity of natural systems in the form of the artificial life and the artificial market. However, SOC remains the question what guarantees the criticality even though the natural systems seem to keep itself in the critical state. In this paper, we focus on the locality of interaction in zero-intelligence plus (ZIP) model. The extremely localized interaction changes the behavior of the ZIP model from equilibrium to intermittency. Although the original ZIP model falls into unstable with some noise, extremely localized interaction model archives robust intermittency against the noise parameter. Further, the statistical property of intermittent behavior shows the power-law nature. 相似文献
18.
Saito W. Domon T. Omura I. Kuraguchi M. Takada Y. Tsuda K. Yamaguchi M. 《Electron Device Letters, IEEE》2006,27(5):326-328
A 13.56-MHz class-E amplifier with a high-voltage GaN HEMT as the main switching device is demonstrated to show the possibility of using GaN HEMTs in high-frequency switching power applications such as RF power-supply applications. The 380-V/1.9-A GaN power HEMT was designed and fabricated for high-voltage power-electronics applications. The demonstrated circuit achieved the output power of 13.4 W and the power efficiency of 91% under a drain-peak voltage as high as 330 V. This result shows that high-voltage GaN devices are suitable for high-frequency switching applications under high dc input voltages of over 100 V. 相似文献
19.
Tatsunari Ohkubo Takaaki Shiina Kayoko Kawaguchi Daisuke Sasaki Rena Inamasu Yue Yang Zhuoqi Li Keizaburo Taninaka Masaki Sakaguchi Shoko Fujimura Hiroshi Sekiguchi Masahiro Kuramochi Tatsuya Arai Sakae Tsuda Yuji C. Sasaki Kazuhiro Mio 《International journal of molecular sciences》2022,23(23)
Membrane proteins play important roles in biological functions, with accompanying allosteric structure changes. Understanding intramolecular dynamics helps elucidate catalytic mechanisms and develop new drugs. In contrast to the various technologies for structural analysis, methods for analyzing intramolecular dynamics are limited. Single-molecule measurements using optical microscopy have been widely used for kinetic analysis. Recently, improvements in detectors and image analysis technology have made it possible to use single-molecule determination methods using X-rays and electron beams, such as diffracted X-ray tracking (DXT), X-ray free electron laser (XFEL) imaging, and cryo-electron microscopy (cryo-EM). High-speed atomic force microscopy (HS-AFM) is a scanning probe microscope that can capture the structural dynamics of biomolecules in real time at the single-molecule level. Time-resolved techniques also facilitate an understanding of real-time intramolecular processes during chemical reactions. In this review, recent advances in membrane protein dynamics visualization techniques were presented. 相似文献
20.
Sanshiro Kanazawa Hiroyuki Okada Dan Riu Yo Mabuchi Chihiro Akazawa Junichi Iwata Kazuto Hoshi Atsuhiko Hikita 《International journal of molecular sciences》2022,23(15)
It is well known that the properties of hematopoietic stem/progenitor cells (HSCs), such as their self-renewal ability and multipotency, are maintained through interactions with mesenchymal stem/stromal cells (MSCs). MSCs are rare cells that are present in the bone marrow and are useful for clinical applications due to their functional ability. To obtain the necessary number of cells, MSCs must be cultured to expand, but this causes a remarkable decrease in stem cell properties, such as multipotency and proliferation ability. In this study, we show that the c-Mpl signal, which is related to the maintenance of hematopoietic stem cells, has an important effect on the proliferation and differentiation ability of MSCs. Utilizing a co-culture system comprising MSCs and HSCs, it is suggested that signaling from hematopoietic cells to MSCs supports cell proliferation. Interestingly, the enhanced proliferation ability of the HSCs was decreased in c-Mpl knock-out HSCs (c-Mpl-KO). In addition, the MSCs co-cultured with c-Mpl-KO HSCs had reduced MSC marker expression (PDGFRa and Sca-1) compared to the MSCs co-cultured with c-Mpl-wild-type HSCs. These results suggest that a hematopoietic–mesenchymal signal exists, and that the state of the HSCs is important for the stability of MSC properties. 相似文献