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排序方式: 共有237条查询结果,搜索用时 15 毫秒
61.
A new leak element using a sintered stainless steel filter with a pore size of less than 1 μm has been developed for in-situ calibrations of ionization gauges (IGs) and quadruple mass spectrometers (QMSs). The gas flow through this leak element realizes molecular flow at an upstream pressure of less than 104 Pa. This new leak element, which is a kind of open-type standard leak, has four advantages. (1) Calibrations for various gas species are available only with this single leak element because the conductance is easily compensated for gas species by molecular mass. (2) Calibrations with multiple pressure points are easily available because the conductance is constant against changing upstream pressure. (3) Calibrations for a gas mixture are available because the interference effect between gas molecules in a gas mixture is negligible. (4) The dependence of flow rate on temperature is small and is compensated theoretically. These advantages were experimentally demonstrated. The stability and uncertainty of the leak element were also evaluated. The changes in the conductance of this leak element were less than 3% over one year. Since the conductance is typically 10−10 · m3/s, the reference gas flow in the range from 10−8 Pa · m3/s to 10−6 Pa m3 is obtained by changing the upstream pressure from 102 Pa to 104 Pa with an uncertainty of approximately 6%. 相似文献
62.
Kenta Kitsuka Kazuhiro Kaneda Mineo Ikematsu Masahiro Iseki Katsuhiko Mushiake Takeo Ohsaka 《Electrochimica acta》2009,55(1):31-36
An electrode composed of silicon/titanium oxide/platinum/titanium dioxide (Si/TiOX/Pt/TiO2) was fabricated by spin-coating TiO2 multilayers on a Si/TiOX/Pt substrate and was used in electrochemical ozone production (EOP). EOP was realized when the Si/TiOX/Pt substrate was completely covered with the TiO2 film and a current efficiency of 7% was achieved at a low current density of 26.7 mA cm−2 in 0.01 M HClO4 at 15 °C. The TiO2 film was found to be of an anatase-type TiO2 and that to comprise aperture structures from the X-ray diffraction (XRD) and transmission electron microscopy (TEM) observations. Moreover, the fabricated TiO2 film was found to be an n-type semiconductor by photoelectrochemical measurements. The high efficiency at a low current density of EOP on the TiO2 n-type semiconductor was explained to result from the electron transfer through the TiO2/HClO4 interface as tunneling current. When the tunneling current passes through a depletion layer of TiO2, the electrode potential is necessarily high enough to facilitate EOP. 相似文献
63.
Shigematsu T Nasuhara Y Nagai G Nomura K Ikarashi K Hirayama M Hayashi M Ueno S Fujii T 《Journal of food science》2010,75(8):M509-M514
Using UV mutagenesis, 2 high-pressure (HP) sensitive (barosensitive) mutants of Saccharomyces cerevisiae were obtained. The HP inactivation of the mutants, as well as their parent strains, followed 1st-order kinetics in the range of 175 to 250 MPa within 600 s. Both mutants showed larger 1st-order inactivation rate constant values or significant loss of viabilities, compared with their parent strains in the pressure range tested. The inactivation rate constant value of one of the mutants was comparable with that of a previously reported highly barosensitive strain, which was generated by deletion of hsp104 in a trehalose deficient strain. The activation volume values of HP inactivation reactions in the 2 mutants were apparently equivalent with those of their parent strains. This suggested that the mutation did not bring drastic volume changes of the key molecules for HP inactivation. Their auxotrophic properties, growth, and ethanol fermentation were identical in mutant and parent strains. The mutants could therefore be useful for fermentations where control by HP processing is desired. 相似文献
64.
Biodesulfurization of alkylated forms of dibenzothiophene and benzothiophene by Sphingomonas subarctica T7b 总被引:1,自引:0,他引:1
Gunam IB Yaku Y Hirano M Yamamura K Tomita F Sone T Asano K 《Journal of Bioscience and Bioengineering》2006,101(4):322-327
Sphingomonas subarctica T7b was isolated from soil in Toyotomi, Hokkaido, Japan as an organism capable of desulfurizing aromatic hydrocarbons in light gas oil (LGO) through enrichment culture. S. subarctica T7b could grow on mineral salt sulfur-free (MSSF) medium with the n-tetradecane oil phase containing dibenzothiophene (DBT), alkyl dibenzothiophenes (alkyl DBTs) or alkyl benzothiophenes (alkyl BTs) as the sole sulfur source and desulfurize these compounds, but could not utilize the tetradecane as a carbon source. This is the first report of a gram-negative bacterium which can desulfurize 4,6-dibutyl DBT and 4,6-dipentyl DBT. The desulfurized product of DBT produced by this strain was 2-hydroxybiphenyl, as in the case of other DBT-desulfurizing bacteria. S. subarctica T7b could desulfurize LGO and the sulfur content was decreased to 41% within 36 h. 相似文献
65.
Shotaro Hayashi Shinsuke Inagi Kenta Hosaka Toshio Fuchigami 《Synthetic Metals》2009,159(17-18):1792-1795
Selective anodic chlorination of a poly(3-hexylthiophene) was successfully carried out by electrochemical polymer reaction. NMR and EDX analyses revealed the selective and sufficient substitution of chlorine atom at the 4-position of the repeating thiophene ring. GPC measurement of the polymer before and after electrolysis indicated that neither decomposition nor propagation of the polymer occurred even after passage of the excess charge. The optical and electrochemical properties of the obtained chlorinated polymer were investigated in detail. 相似文献
66.
Akihisa Kubota Hidekazu Mimura Kouji Inagaki Kenta Arima Yuzo Mori Kazuto Yamauchi 《Journal of Electronic Materials》2005,34(4):439-443
In this work, elastic emission machining (EEM), which is a precise surface-preparation technique using chemical reactions
between the surfaces of work and fine powder particles, is applied to the flattening 4H-SiC (0001) surface. Prepared surfaces
are observed and characterized by optical interferometry, atomic force microscopy (AFM), and low-energy electron diffraction
(LEED). The obtained images show that the processed surface has atomic-level flatness, and the subsurface damage and surface
scratches of the preprocessed surface are almost entirely removed. 相似文献
67.
68.
The effect of surface hydrophobicity on the adsorption behaviour of polyelectrolytes is investigated using graphite and alumina powder slurries. Graphite slurries containing carboxymethylcellulose (CMC) have a relatively low apparent viscosity and afford a sediment with a relatively high packing fraction as compared to that obtained when using sodium polyacrylate (Na-PAA) as a dispersant, although both have the same functional group. As a greater amount of CMC is adsorbed, it is concluded that its adsorption mechanism involves hydrophobic interaction, thus making it a better dispersant for hydrophobic powders in aqueous media. In contrast, Na-PAA is more effective in dispersing relatively hydrophilic powders such as alumina, as it adsorbs mainly through electrostatic interactions. 相似文献
69.
The local b-function bf,p(s) of an n-variate polynomial f∈C[x] (x=(x1,…,xn)) at a point p∈Cn is constant on each stratum of a stratification of Cn. We propose a new method for computing such a stratification and bf,p(s) on each stratum. In the existing method proposed in Oaku (1997b), a primary ideal decomposition of an ideal in C[x,s] is needed and our experiment shows that the primary decomposition can be a bottleneck for computing the stratification. In our new method, the computation can be done by just computing ideal quotients and examining inclusions of algebraic sets. The precise form of a stratum can be obtained by computing the decomposition of the radicals of the ideals in C[x] defining the stratum. We also introduce various techniques for improving the practical efficiency of the implementation and we show results of computations for some examples. 相似文献
70.