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61.
Effect of refraction index and thickness of the light guide in the position-sensitive gamma-ray detector using compact PS-PMTs 总被引:1,自引:0,他引:1
Koji Inoue Haruo Saito Yasuyuki Nagashima Toshio Hyodo Yasuyoshi Nagai Shinichi Muramatsu Shota Nagai 《Radiation Physics and Chemistry》2000,58(5-6):763-766
We constructed a position-sensitive gamma-ray detector consisting of an array of BGO scintillators, a light guide and compact PS-PMTs. The effects of refractive index and thickness of the light guide of a glass plate on the detector performance were investigated. A light guide with higher refractive index and smaller thickness is found better for a good spatial resolution. 相似文献
62.
63.
In a prototype of an adenine analyser, adenosine and adenine nucleotides were derivatized with a fluorescent reagent, bromoacetaldehyde, after separation on a Hitachi gel No. 3012-N column by high-performance liquid chromatography. The previous analyser was improved by using a shorter reaction coil and by introduction of a Hitachi gel No. 3013-N with 5-microns particles of porous polystyrene-divinylbenzene, and applied to estimate the freshness of porgy. Total amounts of ATP, ADP and AMP in an isolated muscle just after death gradually decreased to 60% of the original amount after 5 h, and the ATP content rapidly decreased to 20% after 1 h. A good correlation was found between the levels of total adenine compounds and the energy charge values obtained from nineteen porgies frozen at a prerigour state. On the other hand, there existed no relationship between total adenine levels and the K values, which were indices for estimating freshness of fish. The analyser will be useful to evaluate the freshness of tissues and cells based on the higher contents of total adenine compounds, especially ATP. 相似文献
64.
Preparation of poly(amino‐amide) particles complexed with ZnO particles using silane coupling agents
Yayoi Yoshioka 《Journal of polymer science. Part A, Polymer chemistry》2009,47(19):4908-4918
Poly(amino‐amide) particles were prepared by reacting 4,4′‐diphenyldicarbonyl chloride and 3,3′‐diaminobenzidine using a precipitation polymerization method with ultrasonic irradiation. The resulting particles had a narrow size distribution with an average diameter of 334 nm and showed excellent dispersion stability in water. The particles obtained were then modified with silane coupling agents (GPES) by reacting the amino groups of the poly(amino‐amide) particles with the epoxide rings of the GPES molecules in N,N‐dimethylformamide or N‐methylpyrrolidone using di‐n‐butyltin dilaurate as a catalyst. The amount of GPES covalently bonded to the poly(amino‐amide) particles was found to depend strongly on the reaction solvent and catalyst used. The resulting particles showed a narrow size distribution and the connections among the particles were not observed. On the other hand, the particles before and after modification showed different thermal properties and dispersion stability in water. The GPES‐modified aromatic polyamide particles were then complexed with ZnO particles with an average diameter of about 20 nm in aqueous acetic acid solution. It was found that the surface of the aromatic polyamide particles was covered with ZnO particles via hydrolysis reaction. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4908–4918, 2009 相似文献
65.
Keigo Kobayashi Prof. Hirokazu Kobayashi Prof. Mitsuhiko Maesato Dr. Mikihiro Hayashi Tomokazu Yamamoto Dr. Satoru Yoshioka Prof. Syo Matsumura Prof. Takeharu Sugiyama Dr. Shogo Kawaguchi Prof. Yoshiki Kubota Prof. Hiroshi Nakanishi Prof. Hiroshi Kitagawa 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(23):6678-6682
We report on hexagonal close-packed (hcp) palladium (Pd)–boron (B) nanocrystals (NCs) by heavy B doping into face-centered cubic (fcc) Pd NCs. Scanning transmission electron microscopy–electron energy loss spectroscopy and synchrotron powder X-ray diffraction measurements demonstrated that the B atoms are homogeneously distributed inside the hcp Pd lattice. The large paramagnetic susceptibility of Pd is significantly suppressed in Pd–B NCs in good agreement with the reduction of density of states at Fermi energy suggested by X-ray absorption near-edge structure and theoretical calculations. 相似文献
66.
Prof. Dr. Yoshihiko Yamamoto Kei-ichiro Nishimura Dr. Shota Mori Dr. Masatoshi Shibuya 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(20):5586-5589
In the presence of a cationic Ru catalyst, 1,6-diynes bearing a terminal styryl moiety underwent [2+2+2] cyclization to produce dehydrobiphenylenes fused with a five-membered ring. Although the cycloadducts were unstable toward purification, their one-pot iodine-mediated ring expansion successfully afforded unprecedented bridged ketone products containing a benzo-fused bicyclo[3.2.1] framework. 相似文献
67.
Tomohito Kameda Saya Ito Toshiaki Yoshioka 《Journal of Dispersion Science and Technology》2017,38(7):1063-1066
We found that activated carbon effectively removed urea from solution and that urea adsorption onto activated carbon followed a pseudo-second-order kinetic model. We classified the urea adsorption on activated carbon as physical adsorption and found that it was best described by the Halsey adsorption isotherm, suggesting that the multilayer adsorption of urea molecules on the adsorption sites of activated carbon best characterized the adsorption system. The mechanism of adsorption of urea by activated carbon involved two steps. First, an amino (–NH2) group of urea interacted with a carbonyl (–C?O) group and a hydroxyl (?OH) group on the surface of activated carbon via dipole–dipole interactions. Next, the –C?O group of the urea molecule adsorbed to the activated carbon interacted with another –NH2 group from a second urea molecule, leading to multilayer adsorption. 相似文献
68.
Yoshimi Sueishi Atsushi Miyata Daisuke Yoshioka Masato Kamibayashi Yashige Kotake 《Journal of inclusion phenomena and macrocyclic chemistry》2010,66(3-4):357-364
The effect of CD-inclusion on spin-trapping rates and spin-adduct decay rates for sulfur trioxide radical anion (SO3 ??) was investigated. SO3 ?? radical was produced with UV photolysis of sodium sulfite in basic aqueous solution, and spin-trapped with various spin traps, i.e., PBN (α-phenyl-N-t-butylnitrone), DMPO (5,5-dimethyl pyrroline-1-oxide), and three other phosphoryl DMPO-type spin traps. A modified β-CD, 6-O-α-d-glucosyl-β-cyclodextrin (G-β-CD) having better inclusion properties than β-CD, was employed. Upon adding excess G-β-CD, decay rates of SO3 ?? radical adducts significantly decreased in most spin traps. Half-lives of SO3 ?? radical adducts of phosphoryl spin traps were one to two orders of magnitude longer than that of PBN or DMPO, and the G-β-CD addition further extended the half-life time. The spin traps containing phosphoryl-group all showed higher SO3 ?? trapping rates than those of PBN and DMPO, but two phosphoryl spin traps achieved slower trapping rates by G-β-CD addition. In addition, the structures of CD-inclusion complexes of spin traps were established by means of 1D and 2D NMR measurements. Based on the results, the influences of inclusion on the spin-trapping rate processes and spin-adduct stabilizations were discussed. We conclude that substituents in DMPO-type spin traps may be modified to provide best spin-trapping capabilities in the presence or absence of CD. 相似文献
69.
Chang KS Yoshioka T Kanezashi M Tsuru T Tung KL 《Chemical communications (Cambridge, England)》2010,46(48):9140-9142
A new molecular dynamics simulation method was successfully applied to construct a homogeneous organic-inorganic hybrid silica membrane using the hybrid-pcff (h-pcff) potential function. Analysis suggested that the hybrid BTESE silica membrane provided a looser network and larger cavity size for the enhancement of gas permeability and selectivity. 相似文献
70.
Akihiro Nakamoto Takeshi Saito Shota Miyazaki Masataka Nagao 《Analytica chimica acta》2010,661(1):42-46
A simple, sensitive, and specific method with gas chromatography-mass spectrometry was developed for simultaneous extraction and derivatization of amphetamines (APs) and 3,4-methylenedioxyamphetamines (MDAs) in human urine by using a monolithic silica spin column. All the procedures, such as sample loading, washing, and elution were performed by centrifugation. APs and MDAs in urine were adsorbed on the monolithic silica and derivatized with propyl chloroformate in the column. Methamphetamine-d5 was used as an internal standard. The linear ranges were 0.01-5.0 μg mL−1 for methamphetamine (MA) and 3,4-methylenedioxymethamphetamine (MDMA) and 0.02-5.0 μg mL−1 for amphetamine (AP) and 3,4-methylenedioxyamphetamine (MDA) (coefficient of correlation ≧0.995). The recovery of APs and MDAs in urine was 84-94%, and the relative standard deviation of the intra- and interday reproducibility for urine samples containing 0.1, 1.0, and 4.0 μg mL−1 of APs and MDAs ranged from 1.4% to 13.6%. The lowest detection limit (signal-to-noise ratio ≧ 3) in urine was 5 ng mL−1 for MA and MDMA and 10 ng mL−1 for AP and MDA. The proposed method can be used to perform simultaneous extraction and derivatization on spin columns that have been loaded with a small quantity of solvent by using centrifugation. 相似文献