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排序方式: 共有1422条查询结果,搜索用时 15 毫秒
41.
Tomohiro Isogai Kazuhiro Hirooka Tetsuro Tojo Hitoshi Takebayashi Morihiro Saito Minoru Inaba Akimasa Tasaka 《Electrochimica acta》2011,56(12):4425
Metal fluoride added carbon anodes treated by pre-electrolysis were investigated for electrolytic production of nitrogen trifluoride (NF3) in molten NH4F·KF·4HF at 100 °C. The conditions for pre-electrolysis were first optimized using a graphite sheet anode as a model anode. The formation of fluorine-graphite intercalation compounds (fluorine-GICs) with semi-covalent C–F bonds, (CxF)n, on the MgF2 and CaF2 added carbon anode surface was accelerated by pre-electrolysis at potentials less than 4.0 V. Critical current densities (CCD) on the MgF2 added carbon anodes pre-electrolyzed under various conditions were determined, and the highest CCD was 290 mA cm−2 obtained for that pre-electrolyzed at 3.5 V for 500 C cm−2. This anode was successfully used in the electrolysis at 100 mA cm−2 for 290 h and the maximum NF3 current efficiency was 55%. From these results, it was concluded that the metal fluoride added carbon anode treated by pre-electrolysis has a high potential for electrolytic production of NF3 at higher current density. 相似文献
42.
A fluorous micellar system in water has been created to produce a large interfacial area between these media that retains substrates, effectively facilitating intermolecular Diels–Alder reactions due to repulsion effects from both media. Because LiFOS functioned not only as a surfactant but also as a supporting electrolyte, an electrochemical approach could be introduced to evaluate the rate acceleration effects. The measurement of the particle size distribution of the fluorous micelles clearly supported these evaluations. 相似文献
43.
44.
Satoshi Murakami Kazuhiro Satou Taturo Kijima Masataka Watanabe Taeko Izumi 《European Journal of Lipid Science and Technology》2011,113(4):450-458
The enantiopure of (R)‐(?) MαNPA was allowed to react with racemic 18‐(tert‐butyldimethylsilyloxy)‐5‐octadecayne‐7‐ol which was derived from dodecane‐1,12‐diol, yielding diastereomeric esters mixture. These racemic esters were easily separated by HPLC on silica‐gel. The absolute configurations of the first‐eluted diastereomeric esters from the separated esters were determined using 1H NMR anisotropy method. Analysis on 1H NMR spectra and HPLC elution time of the synthesized esters and those of MαNP ester derived from natural methyl‐12‐hydroxystealate showed that the absolute configuration of natural 12‐hydroxystearic acid was R form, and the enantiomeric excess was over 99%. 相似文献
45.
Effects of spraying ozonated water on the severity of powdery mildew infection, visible disorder/injury occurrence, and net photosynthesis in cucumbers were investigated. The severity in the ozonated water treatment was contained to almost the same level throughout the 14-day period of the experiment, while the severity steadily increased in the non-treated control and distilled water treatment. Neither visible disorder/injury on the leaves nor a large difference in net photosynthesis between before and after spraying the ozonated water was observed. The results indicate that ozonated water can be at least a partial alternative to agricultural chemical fungicides for powdery mildew on cucumber leaves. 相似文献
46.
Kazuhiro Yoshioka Ei-ichi TazawaKenji Kawai Tomoyuki Enohata 《Cement and Concrete Research》2002,32(10):1507-1513
Adsorption characteristics of various superplasticizers on portland cement component minerals were investigated. Adsorption isotherms of various types of superplasticizers and ζ-potentials of cement component minerals at the maximum adsorption of the superplasticizers were measured. The value of the adsorption isotherm was calculated from the amount of the superplasticizer adsorbed on a cement component mineral in an equilibrated solution. The maximum amounts of adsorption and the adsorption isotherms varied with types of component mineral and superplasticizer. For all types of superplasticizers, a larger amount of superplasticizer was adsorbed on C3A and C4AF than C3S and C2S. However, the equilibrated concentration of each superplasticizer at the maximum adsorption was not influenced by types of superplasticizer. Without superplasticizer, C3S and C2S had negative ζ-potential. On the contrary, C3A and C4AF had positive ζ-potential. Therefore, accelerated coagulation of cement particles might occur due to their electrostatic potentials that are opposite each other. However, all component minerals of cement had negative ζ-potential when they were mixed with any superplasticizer. Fluidity of fresh cement paste is improved due to electrostatic repulsion acting between particles. 相似文献
47.
The effect of the N-linked glycans on structural features and physicochemical functions of soybean β-conglycinin homotrimers 总被引:2,自引:0,他引:2
Nobuyuki Maruyama Mohamad Ramlan Mohamed Salleh Koji Takahashi Kazuhiro Yagasaki Hideyuki Goto Naho Hontani Shuko Nakagawa Shigeru Utsumi 《Journal of the American Oil Chemists' Society》2002,79(2):139-144
β-Conglycinin is a trimeric protein consisting of three subunits, α,α′,and β, which are N-glycosylated. The α and α′ subunits
contain extension regions in addition to core regions common to all subunits. We purified homogeneous trimers consisting of
only α, α′, or β from mutant soybean cultivars containing β-conglycinin lacking one or two subunits: α homotrimers from an
α′-lacking mutant, α′ homotrimers from an α-lacking mutant, and β homotrimers from an α-and α′-lacking mutant. Structural
features and physicochemical functions of the three homotrimers were examined and compared with those of recombinant homotrimers
having no N-linked glycans. The native homotrimers have secondary structures very similar to those of the recombinant ones.
In analogy with the recombinant homotrimers, the native ones exhibit different thermal stabilities from one another (β>α′>α),
and the native α and α′ homotrimers exhibit better solubility, emulsifying ability, and heat-induced association than the
native β homotrimer. Further, the N-linked glycans contribute to solubilities of the three subunits at low ionic strength
(μ=0.08) and to the emulsifying ability of the native β homotrimer. N-Linked glycans also prevent heat-induced associations
of the native α and α′ homotrimers but do not contribute to the secondary structure and the thermal stability of β-conglycinin. 相似文献
48.
Wataru Nakao Hiroyuki Fukuyama Kazuhiro Nagata 《Journal of the American Ceramic Society》2002,85(4):889-896
The experimental method for the high-temperature reaction equilibria in the AlN-Al2 O3 system has been established. The equilibrium N2 -CO gas compositions coexisting with AlN- Al2 O3 -graphite have been successfully measured by quadrupole mass spectrometry and gas chromatography. From the obtained results, the standard Gibbs energy change of the forming reaction of AlN by carbothermal nitridation is determined at temperatures ranging from 1723 to 1899 K:
From the obtained result, the standard Gibbs energy of formation of AlN and the third-law enthalpy of formation of AlN at 298.15 K are derived as
The disagreement between the present results and values in the NIST–JANAF thermodynamic table is discussed. 相似文献
From the obtained result, the standard Gibbs energy of formation of AlN and the third-law enthalpy of formation of AlN at 298.15 K are derived as
The disagreement between the present results and values in the NIST–JANAF thermodynamic table is discussed. 相似文献
49.
Katsuyuki Kunii Kazuhiro Narahara Shoji Yamanaka 《Microporous and mesoporous materials》2001,50(2-3):181-185
A microporous aluminophosphate molecular sieve, AlPO4-H3, was prepared without using organic templates. It was crystallized at temperatures as low as 90 °C from aluminophosphate gels with a molar ratio of Al2O3/P2O51; the addition of seed crystals was essential. AlPO4-H3 was topotactically and irreversibly converted into AlPO4-D at 300 °C, which adsorbed water up to 0.2 ml/g at 25 °C, although nitrogen gas was hardly adsorbed at liquid nitrogen temperature. 相似文献
50.
Kazuhiro Suzuki Hideo Fukuda Takatoshi Yamada Atsuhito Sawabe 《Diamond and Related Materials》2001,10(12):570-2156
We obtained an epitaxially grown free-standing diamond platelet utilizing epitaxial diamond film formed on a {100} iridium surface using a d.c. plasma CVD process. Iridium was selected as a suitable substrate material for the heteroepitaxy of diamond based on original criteria. Confocal Raman spectroscopy revealed that the diamond platelet contained little or no non-diamond carbon. The obtained diamond platelet is transparent to visible light and cleavable along the 110 direction on the surface. The angles between the top surface and the cross-sectional surfaces are approximately 55°, almost equal to the theoretical angle of 54.74° between {100} and {111} planes in cubic crystals. Therefore, the cross-sectional surfaces would be {111} planes of a typical facet for single-crystalline diamond. This means that the diamond platelet we have formed has relatively good crystallinity. 相似文献