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961.
The extraction behaviors of bismuth(III) with carboxylic acid (HL), which have not yet been clearly elucidated, because of the precipitation of hydroxide, were studied using the 2-bromoalkanoic acid in benzene and in hexane systems under aqueous conditions of high acidity at I = 1.0 M ((H,Li)NO3). The extraction equilibria were analyzed based on the-initial concentration of nitric acid and the concentration of bismuth(III) extracted in the organic phase. The extracted species and the logarithmic values of the extraction constant (log Kex) were found to be a single species of BiL3(HL)3 for the systems of 2-bromooctanoic acid/benzene (log Kex = -1.66) and 2-bromohexadecanoic acid/benzene (-1.58), and to be two species of BiL3(HL)4 (-1.01) and Bi3L9HL (-1.62) for the system of 2-bromooctanoic acid/hexane, where the monomer was dominant at a higher reagent concentration.  相似文献   
962.
The hydrogen content in a-Si1−xGex:H thin films is an important factor deciding the density and the optical band gap. We measured the elemental depth profiles of hydrogen together with Si and Ge by elastic recoil detection analysis (ERDA) combined with Rutherford backscattering (RBS) using MeV He2+ ions. In order to determine the hydrogen depth profiles precisely, the energy- and angle-dependent recoil cross-sections were measured in advance for the standard sample of a CH3+-implanted Si substrate. The cross-sections obtained here are reproduced well by a simple expression based on the partial wave analysis assuming a square well potential (width: r0 = 2.67 × 10−13 cm, depth: V0 = −36.9 MeV) within 1%. For the a-Si1−xGex:H films whose elemental compositions were determined by ERDA/RBS, we measured the secondary ions yields of HCs2+, SiCs2+, H, Si and Ge as a function of Ge concentration x. As a result, it is found that the useful yield ratios of HCs2+/SiCs2+, H/Si and Ge/Si are almost constant and thus the elemental depth profiles of the a-Si1−xGex:H films can be also determined by secondary ion mass spectrometry (SIMS) within 10% free from a matrix effect.  相似文献   
963.
In the field of materials science, π-conjugated molecules bearing a group 16 heteroatom are of great importance. Sulfur or selenium containing porphyrins were successfully synthesized using the transition-metal-catalyzed reaction with diphenyl dichalcogenides. NMR studies indicated the preferential formation of the (Z)-isomer.  相似文献   
964.
965.
Structural modification of a polypeptide hormone, glucagon, by a hydroxyl radical in vitro was investigated by reversed‐phase high‐performance liquid chromatography (RP‐HPLC), and the oxidized site of glucagon was detected by electrospray ionization tandem mass spectrometry (ESI‐MS/MS). It was shown that 27methionine (Met) was oxidized to 27Met sulfoxide by hydroxyl radical, and the production rate of 27Met sulfoxide was faster than that by hydrogen peroxide. In addition, production of 27Met sulfoxide enantiomer was confirmed by RP‐HPLC analysis. cAMP production in a HepG2 cell induced by 27Met sulfoxide glucagon was reduced to approximately 75% as compared with that induced by the native form of glucagon. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
966.
967.
We consider the free boundary problem for an incompressible ideal fluid in the two-dimensional space. We show the unique existence of the solution, locally in time, even if the initial surface and the bottom are uneven.  相似文献   
968.
969.
We realized an efficient laser diode-pumped Nd:GdVO4 laser with crystals grown by the floating zone method. In the lasing experiment, a slope efficiency of 78% was achieved with a 1 at.% Nd-doped crystal by pumping at 879 nm. Furthermore, excellent pulsed laser operation was demonstrated with the Nd:GdVO4 crystal by using an acousto-optical (AO) Q-switch. A pulse width of 7 ns was observed when the pulse-repetition frequency was 40 kHz. It is the shortest pulse width recorded in the case of the AO Q-switched Nd:GdVO4 laser.  相似文献   
970.
Operation tests of a cavity designed for high purity mode operation of the submillimeter wave gyrotron FU VA has been carried out successfully. The observed emission patterns of several cavity modes appear very pure and are compared with calculated results. High purity mode operation has the advantage of making the conversion to Gaussian-like beams more efficient.  相似文献   
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