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排序方式: 共有1398条查询结果,搜索用时 15 毫秒
841.
Zhaoxia Song Atsushi Takahashi Naoki Mimura Tadahiro Fujitani 《Catalysis Letters》2009,131(3-4):364-369
In this work, we studied the conversion of ethanol to propylene over ZSM-5 zeolites. The catalytic performance of H-ZSM-5 (Si/Al2 = 30, 80, and 280) and ZSM-5 (Si/Al2 = 80) modified with various metals was investigated. H-ZSM-5(Si/Al2 = 80) afforded high propylene yield, which indicates that a moderate surface acidity favored propylene production. Zr-modified ZSM-5(80) gave the highest yield (32%) of propylene at 773 K. Furthermore, the catalytic stability of the zeolite was improved by the modification of zirconium. The surface acidity and the presence of metal ions played important roles on the production of propylene. 相似文献
842.
Isao Miyazaki Hideo Okumura Dr. Siro Simizu Dr. Yoshikazu Takahashi Dr. Naoki Kanoh Dr. Yasuhiko Muraoka Dr. Yoshiaki Nonomura Dr. Hiroyuki Osada Prof. 《Chembiochem : a European journal of chemical biology》2009,10(5):845-852
Natural product libraries for SAR studies : We used a chemical array platform to study the SARs of bleomycin (BLM) derivatives and Shble protein. The on‐chip SARs suggested that several domains are important for recognition of BLMs by Shble protein. In particular, the C‐terminal tail and the propionamide moiety in pyrimidoblamic acid (PBA) were shown to be important for the binding.
843.
Naoki Uchiyama Shigenori Sano Takaya Nakamura 《The International Journal of Advanced Manufacturing Technology》2009,44(5-6):428-436
Contouring control is an effective method for computer numerical controlled machining, and various such designs have been proposed to date. However, the compliance of the transmission mechanism is not considered in most existent contouring controller designs. This paper presents a new contouring control system design considering the compliance of a transmission mechanism based on a fourth-order model of feed drive dynamics. First, we present a controller design that enables the controller gain assignment for reducing the error component orthogonal to the desired contour curve, independent of the tangential error component. Although this design provides better control performance with small control input variance, there exists an inherent contour error because of the difficulty in calculating the exact contour error for any contour curve in real time. To address this problem, a reference adjustment method is used to estimate the actual contour error. The effectiveness of the proposed design is experimentally verified by comparing the control performance with a design based on a plant model that neglects the compliance. 相似文献
844.
Behavioral analysis revealed that S-(+)-isopiperitenone [(S)-3-methyl-6-isopropenyl-2-cyclohexen-1-one], previously identified as an alarm pheromone, is also the female sex pheromone
of Tyrophagus similis (Astigmata: Acaridae), showing maximum male attraction at a dose of 0.1 female equivalent. Although the antipode, R-(−)-isopiperitenone, was not detectable in the mite extract, this synthetic optical isomer (80% e.e.) also induced activity
at a dose of 100 ng, a response indicative of S-(+)-isopiperitenone being the active compound. The average content was determined to be 38.5 ng per female and 19.8 ng per
male. This is the first example of an astigmatid mite species possessing a compound that functions as an alarm as well as
a sex pheromone. 相似文献
845.
Watanabe H Akaboshi C Sekido H Tanaka K Tanaka K Shimojo N 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2012,53(2):98-104
Changes in egg protein contents by cooking were measured with an ELISA kit using Tris-HCl buffer in model foods including cake, meatballs, pasta and pudding made with whole egg, egg-white and egg-yolk. The egg protein contents were lowest in the deep-fried model foods of cakes and meatballs. Ovalbumin (OVA) was undetectable (<1 μg/g) and ovomucoid (OVM) was lowest in pouched meatballs, suggesting that processing temperature and uniform heat-treatment affect the detection of egg protein. Furthermore, egg protein contents were below 6 μg/g in the pouched meatballs and pasta made with egg-yolk, and OVA and OVM were not detected by Western blotting analysis with human IgE from patients' serum. On the other hand, processed egg proteins were detected with an ELISA kit using a surfactant and reductant in the extract buffer. 相似文献
846.
K Aoyama H Akashi N Mochizuki Y Ito T Miyashita S Lee M Ogiso M Maeda S Kai H Tanaka H Noriduki H Hiraoka T Tanaka E Ishikuro Y Itoh T Nagayama M Nakajima S Naito Y Sugita-Konishi 《Shokuhin eiseigaku zasshi. Journal of the Food Hygienic Society of Japan》2012,53(3):152-156
To evaluate LC methods with UV or MS detection for simultaneous analysis of deoxynivalenol (DON) and nivalenol (NIV) in wheat, an interlaboratory study was conducted in 11 laboratories. DON and NIV were purified using a multifunctional column, and their concentrations were determined using LC-UV or LC-MS(/MS). No internal standards were used. Three fortified wheat samples (0.1, 0.5 and 1 mg/kg), one naturally contaminated wheat sample, and one blank wheat sample were used. The recoveries ranged from 90% to 110% for DON and from 76% to 83% for NIV. For DON, the relative standard deviations for repeatability (RSDr) ranged from 1.1% to 7.6%. The relative standard deviations for reproducibility (RSDr) ranged from 7.2% to 25.2%. For NIV, the RSDr ranged from 2.0% to 10.7%, and the RSDr ranged from 7.0% to 31.4%. Regardless of sample and detector, the HorRat values for DON and NIV ranged from 0.4 to 1.4. Both LC-UV and LC-MS(/MS) methods were considered to be suitable for application as an official method. 相似文献
847.
848.
Youngbae Han Naoki Shikazono Nobuhide Kasagi 《International Journal of Heat and Mass Transfer》2012,55(4):547-555
Flow boiling in micro channels is attracting large attention since it leads to large heat transfer area per unit volume. Generated vapor bubbles in micro channels are elongated due to the restriction of channel wall, and thus slug flow becomes one of the main flow regimes. In slug flow, sequential bubbles are confined by the liquid slugs, and thin liquid film is formed between tube wall and bubble. Liquid film evaporation is one of the main heat transfer mechanisms in micro channels and liquid film thickness is a very important parameter which determines heat transfer coefficient. In the present study, liquid film thickness is measured by laser focus displacement meter under flow boiling condition and compared with the correlation proposed for an adiabatic flow. The relationship between liquid film thickness and heat transfer coefficient is also investigated. Initial liquid film thickness under flow boiling condition can be predicted well by the correlation proposed under adiabatic condition. Under flow boiling condition, liquid film surface fluctuates due to high vapor velocity and shows periodic pattern against time. Frequency of periodic pattern increases with heat flux. At low quality, heat transfer coefficients calculated from measured liquid film thickness show good accordance with heat transfer coefficients obtained directly from wall temperature measurements. 相似文献
849.
Catalysis using gold is emerging as an important field of research in connection with 'green' chemistry. Several hypotheses have been presented to explain the markedly high activities of Au catalysts. So far, the origin of the catalytic activities of supported Au catalysts can be assigned to the perimeter interfaces between Au nanoclusters and the support. However, the genesis of the catalytic activities of colloidal Au-based bimetallic nanoclusters is unclear. Moreover, it is still a challenge to synthesize Au-based colloidal catalysts with high activity. Here we now present the 'crown-jewel' concept (Supplementary Fig. S1) for preparation of catalytically highly Au-based colloidal catalysts. Au-Pd colloidal catalysts containing an abundance of top (vertex or corner) Au atoms were synthesized according to the strategy on a large scale. Our results indicate that the genesis of the high activity of the catalysts could be ascribed to the presence of negatively charged top Au atoms. 相似文献
850.
Kundu LM Tsukada H Matsuoka Y Kanayama N Takarada T Maeda M 《Analytical chemistry》2012,84(12):5204-5209
An affinity capillary electrophoresis method was developed to determine a binding constant between a peptide nucleic acid (PNA) and a hairpin-structured DNA. A diblock copolymer composed of PNA and polyethylene glycol (PEG) was synthesized as a novel affinity probe. The base sequence of the probe's PNA segment was complementary to a hairpin-structured region of a 60-base single-stranded DNA (ssDNA). Upon applying a voltage, the DNA hairpin migrated slowly compared to a random sequence ssDNA in the presence of the PNA probe. This retardation was induced by strand invasion of the PNA into the DNA hairpin to form a hybridized complex, where the PEG segment received a large amount of hydrodynamic friction during electrophoresis. The binding constant between the PNA probe and the DNA hairpin was easily determined by mobility analysis. This simple method would be potentially beneficial in studying binding behaviors of various artificial nucleotides to natural DNA or RNA. 相似文献