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排序方式: 共有206条查询结果,搜索用时 28 毫秒
11.
Koichi Mitsukura Hiromu Sakamoto Haruka Kubo Toyokazu Yoshida Toru Nagasawa 《Journal of Bioscience and Bioengineering》2010,109(6):550-553
To efficiently produce 1,3-adamantanediol (1,3-ad(OH)2) from 1-adamantanol (1-adOH), our stocks of culture strains and soil microorganisms were surveyed for hydroxylation activity towards 1-adOH. Among them, the soil actinomycete SA8 showing the highest hydroxylation activity was identified as Streptomyces sp. based on 16S ribosomal DNA sequence analysis. The reaction products were purified by silica gel column chromatography, and from NMR and MS analyses, they were identified as 1,3-ad(OH)2 and 1,4-ad(OH)2. Streptomyces sp. SA8 produced 5.9 g l? 1 1,3-ad(OH)2from 6.2 g l? 1 1-adOH in culture broth after 120 h at 25 °C. Using resting cells, 2.3 g l? 1 1,3-ad(OH)2 was produced after 96 h of incubation at a 69% conversion rate. In both cases, 1,4-ad(OH)2 was formed as a byproduct at a rate of about 15%. Strain SA8 also hydroxylated 2-adamantanol and 2-methyl-2-adamantanol. 相似文献
12.
Chun Li Naoe Isshiki Hiromu Saito Kazufumi Kohno Akinori Toyota 《Polymer Bulletin》2009,63(6):779-788
We investigated the formation of inclusion complexes (ICs) between cyclodextrins (CDs) with different cavity size and polyolefin
(PO) with different side chains by using Fourier transform infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (WAXD)
and differential scanning calorimetry. The analysis of FTIR spectra revealed that the resultants were complexes of CD and
PO, and the analysis of WAXD revealed that the molecules of CD had a channel structure due to the formation of ICs. We found
that IC could not be obtained when the cavity size of CD was small for PO molecules to thread and it was too large for cross-sectional
area of PO molecules. Thus, it was found that PO1 with few side chains could form IC with α-CD, and PO2 with ethyl side chain
could form IC with β-CD and γ-CD, while the PO3 with 2-methyl-propyl side chain could form IC with γ-CD. These results suggest
that the cross-sectional areas of polymer and the cavity size of CDs play critical roles in the formation of ICs. It is only
possible to form ICs when the polymer chains can tread into cavities of CDs, and the space between the polymer and CD is suitable
to provide enough intermolecular interaction to keep the structure of IC stable. 相似文献
13.
Hiroyuki Kurachi Sashiro Uemura Jyunko Yotani Takeshi Nagasako Hiromu Yamada Tomotaka Ezaki Tsuyoshi Maesoba Takehiro Nakao Masaaki Ito Akira Sakurai Yahachi Saito Hisanori Shinohara 《Journal of the Society for Information Display》2005,13(9):727-733
Abstract— The synthesis of carbon‐nanotube (CNT) field emitters for FEDs by thermal chemical vapor deposition (CVD) and their structural and emission characterization are described. Multi‐walled nanotubes (MWNTs) were grown on patterned metal‐base electrodes by thermal CVD, and the grown CNTs formed a network structured layer covering the surfaces of the metal electrode uniformly, which realized uniform distribution of electron emission. A technique for growing narrow MWNTs was also developed in order to reduce the driving voltage. The diameter of MWNT depends on the growth temperature, and it has changed from 40 nm at the low temperature (675°C) to 10–15 nm at the high temperature (900–1000°C). Moreover, narrower MWNTs were grown by using the metal‐base electrode covered with a thin alumina layer and a metal catalyst layer. Double‐walled nanotubes (DWNTs) were also observed among narrow MWNTs. The emission from the narrow CNTs showed a low turn‐on electric field of 1.5 V/μm at the as‐grown layer. 相似文献
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Reinforcement learning (RL) has been widely used to solve problems with a little feedback from environment. Q learning can solve Markov decision processes (MDPs) quite well. For partially observable Markov decision processes (POMDPs), a recurrent neural network (RNN) can be used to approximate Q values. However, learning time for these problems is typically very long. We present a new combination of RL and RNN to find a good policy for POMDPs in a shorter learning time. This method contains two phases: firstly, state space is divided into two groups (fully observable state group and hidden state group); secondly, a Q value table is used to store values of fully observable states and an RNN is used to approximate values for hidden states. Results of experiments in two grid world problems show that the proposed method enables an agent to acquire a policy with better learning performance compared to the method using only a RNN. 相似文献
16.
Kholid Akhmad Hiroaki Okamoto Akio Kitamura Hiromu Matsuda Fumio Yamamoto Yoshihiro Hamakawa 《Solar Energy Materials & Solar Cells》1997,47(1-4)
The experiments investigated phenomena related to direct contact between the DC output of a PV array and the AC power from the utility grid. The results show that the DC power flows through the distribution transformers (DC-injection) saturating their magnetic circuits. The saturation of magnetic circuits makes peak currents, incorporating a large portion of even harmonics, flow through the high-voltage side of the distribution transformer, adding the level of harmonic distortion of its exciting current. With the increase of injecting DC-current to the utility grid, peak currents at the primary side of distribution transformer increases the most, and even among the same effective (rms) values, the increase of primary side current is larger than that of the secondary side current. 相似文献
17.
Hiroyuki Hamada Hiroyuki Kato Naoto Ito Yoshihiko Takase Hironobu Nanbu Shoko Mishima Hiromu Sakaki Kiyotaka Sato 《European Journal of Lipid Science and Technology》2010,112(12):1323-1330
Biodiesel fuels (BDF) have many problems in the cold due to their crystallization properties. In particular, precipitation of large crystals of high‐melting fractions in BDF at low temperatures remarkably changes cold flow property of BDF and, thereby, it increases the values of cold filter plugging point. In this study, we evaluated polyglycerol esters of fatty acids (PGE) and ethylene‐vinyl acetate co‐polymer (EVA) as chemical additives to improve the cold flow property of palm oil‐based FAME (PFME). The results of solid fat content measurement indicate that the simultaneous addition of PGE and EVA showed synergistic effects on suppression of crystallization of PFME, however such effect was not observed when EVA was used alone. DSC thermograms indicated that the PGE additives not only decreased the crystallization temperature but also kinetically suppressed the crystal growth. Polarized light microscopy showed that the simultaneous addition of PGE and EVA led to the formation of considerably small and fine‐dispersed crystals of PFME. These results indicate that combined effects of PGE and EVA caused the formation of fine‐dispersed PFME crystals, which could improve the viscous properties of palm oil‐based BDF at relatively cold temperatures. 相似文献
18.
19.
The γ‐cyclodextrin (γ‐CD) inclusion complexes (ICs) with four kinds of polyolefin (PO) as guest molecules were prepared. The crystallization behavior of isotactic polypropylene (iPP) blended with the γ‐CD and γ‐CD–PO ICs was investigated by differential scanning calorimetry, polarized optical microscopy, and light scattering. The iPP blended with the ICs was found to exhibit higher crystallization temperature (TC), smaller spherulites, and faster crystallization rate than those of neat iPP, indicating that the ICs play a role of nucleating agent on the crystallization of iPP and induce accelerated crystallization. The IC with PO having higher TC as guest molecules showed higher nucleation effect than the IC with PO having lower TC as guest molecules. The results suggest that the nucleation effect of these ICs was affected by the kinds of the guest molecules. The higher TC guest molecules could result in higher nucleation effect. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
20.