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81.
82.
Bubbly flow undergoing a steep pressure gradient 总被引:1,自引:0,他引:1
The effects of a steep pressure gradient on bubbly flow were studied to determine the cause of noise emanating from components of a piping system. We used an orifice to generate a local pressure difference. The behavior of bubbles passing through the orifice was observed by using a video camera, and the noise was measured by a condenser microphone outside the pipe. It was found that the sound pressure level of noise generated by a bubbly flow was proportional to the pressure difference. An empirical formula for estimating noise level is proposed. The changes in size and number of bubbles passing through an orifice were found related to the breakup, which is affected by pressure difference rather than airflow rate. The breakup of a single bubble undergoing a steep pressure difference was observed to determine the mechanism of sound generation. It was found that a bubble was broken by impingement of an inward protrusion in the bubble. The growth rate of the protrusion depended on the pressure difference. 相似文献
83.
Toshiki Mochizuki Kenichiro TodorokiKoichi Inoue Jun Zhe MinToshimasa Toyo’oka 《Analytica chimica acta》2014
l-Pyroglutamic acid succinimidyl ester (l-PGA-OSu) and its isotopic variant (l-PGA[d5]-OSu) were newly synthesized and evaluated as the chiral labeling reagents for the enantioseparation of amino acids, in terms of separation efficiency by reversed-phase chromatography and detection sensitivity by ESI-MS/MS. The enantiomers of amino acids were easily labeled with the reagents at 60 °C within 10 min in an alkaline medium containing triethylamine. Although all the diastereomers derived from 18 proteolytic amino acids could not be satisfactorily separated, the pairs of 9 amino acids were completely separated by reversed-phase chromatography using the small particle (1.7 μm) ODS column (Rs = 1.95–8.05). The characteristic daughter ions, i.e., m/z 84.04 and m/z 89.04, were detected from all the derivatives by the collision induced dissociation of the protonated molecular ions. A highly sensitive detection at a low-fmol level (0.5–3.2 fmol) was also obtained from the selected reaction monitoring (SRM) chromatograms. An isotope labeling strategy using light and heavy l-PGA-OSu for the differential analysis of the dl-amino acids in different sample groups is also presented in this paper. The differential analysis of biological sample (i.e., human serum) and food product (i.e., yogurt) were tried to demonstrate the efficiency of the proposed method. The ratios of the dl-amino acids in human serum samples, spiked with the different concentrations of d-amino acids, were determined by the procedures using l-PGA-OSu and l-PGA[d5]-OSu. The d/l ratios in the two sample groups at different concentrations of amino acids were similar to the theoretical values. Furthermore, the ratios of d/l-alanine values in different yogurt products were comparable to the ratios obtained from the d/l values using only light reagent (i.e., l-PGA-OSu). Consequently, the proposed strategy is useful for the differential analysis not only in biological samples but also in food products. 相似文献
84.
Masaaki Saitow Tomonori Ida Yuji Mochizuki 《International journal of quantum chemistry》2014,114(9):577-586
The self‐energy shift in the orbital relaxation (OR) term of the polarization propagator complete through the second‐order is presented. In combination with the optimal damping parameter in the OR term, the modified propagator produces the excitation energy of the coupled‐cluster with singles and doubles (CCSD) accuracy. The self‐energy shift requires the floating‐point operation of , where N refers to the magnitude of the molecular size. Because the second‐order polarization propagator requires the floating‐point operation of , the additional computational effort to construct the self‐energy is negligibly small. Numerical results are shown for several molecules including glycine, 2,3,5,6‐tetrafluorobenzene, and naphthalene, and promising agreements with those of CCSD are confirmed within less than 0.2 eV. The basis set dependence is also tested for the water molecule using aug‐cc‐pV NZ (N = D–7), where this newly developed approach mimics the behavior of the CCSD values. The self‐energy shifting for the second‐order response matrix in combination with the use of a dumping parameter is efficiently implemented for calculations of medium‐sized molecular systems, including glycine and naphthalene. The developed approach provides CCSD‐like accuracy at a more affordable computational expense. © 2014 Wiley Periodicals, Inc. 相似文献
85.
Kuniaki Tatsuta Sonoko TokishitaTomohiro Fukuda Takaaki KanoTadaaki Komiya Seijiro Hosokawa 《Tetrahedron letters》2011,52(9):983-986
K1115 B1, isolated from the broth of Streptomyces species, was found to be a mixture of stereoisomers. Authors synthesized all stereoisomers of K1115 B1 by convergent synthesis coupling a rhamnose derivative, an isobenzofuranone, and a chiral tetraol. Comparison of 1H NMR spectra and optical rotations made it clear that the absolute structures of K1115 B1α (the major isomer) and K1115 B1β (the minor isomer) were (1R, 17S)- and (1R, 17R)-configurations, respectively. The optical rotations of the stereoisomers revealed that alnumycin, reported as the identical structure with K1115 B1, might be another mixture of stereoisomers. 相似文献
86.
Fujii S Mochizuki M Aono K Hamasaki S Murakami R Nakamura Y 《Langmuir : the ACS journal of surfaces and colloids》2011,27(21):12902-12909
Polystyrene (PS) latex particles carrying pH-responsive poly[2-(diethylamino)ethyl methacrylate] (PDEA) hair (PDEA-PS particles) were synthesized by dispersion polymerization and characterized in terms of diameter, diameter distribution, morphology, chemical composition, surface chemistry, and pH-response using scanning electron microscopy (SEM), elemental microanalysis, (1)H nuclear magnetic resonance spectroscopy, the laser diffraction method, and zeta potential measurements. The hairy particles can act as pH-responsive stabilizers of aqueous foams by adsorption at the air-water surface. Above pH 8.0, where particles have nonprotonated PDEA hair, which is relatively hydrophobic, particle-stabilized foams are stable for at least 1 month. Optical microscopy and SEM confirmed that flocculated PDEA-PS latex particles were adsorbed at the air-water interface and stabilized the aqueous foams. At pH 6.1 and 7.1, relatively stable foams can be prepared that remain stable for at least 24 h. SEM studies indicated that the PDEA-PS particles were adsorbed at the air-water interface as a monolayer at pH 6.1. At pH 5.1 and 3.1, where the particles have cationic water-soluble PDEA hairs with hydrophilic character, no foam was formed. Rapid defoamation can be induced by lowering the solution pH; the addition of acid caused the in situ protonation of 2-(diethylamino)ethyl methacrylate residues, which impart water-soluble hydrophilic character to the PDEA hair, and the PDEA-PS particles desorbed from the air-water interface. The foaming and defoaming cycles could be repeated at least five times. 相似文献
87.
Hirotaka Fujita Qingrong Qian Takao Fujii Kazuhiro Mochizuki Akiyoshi Sakoda 《Adsorption》2011,17(5):869-879
A novel bioethanol separation process was proposed in this study employing molecular sieving carbon (MSC) as an adsorbent,
whose pore diameter is close to molecular size of ethanol. In the proposed process, fermentation broth is first introduced
to the adsorption bed packed with MSC. In this step, ethanol is selectively adsorbed onto MSC, with highly enriching ethanol
in the micropore of MSC. Subsequently, the concentrated ethanol is desorbed from MSC to gaseous phase, resulting in further
purification of ethanol owing to a considerable difference in desorption rate between water and ethanol; Because of molecular
sieving effect of MSC, the desorption rate of ethanol is much smaller than that of water. To establish this process, adsorption
equilibrium and kinetics of ethanol on various MSCs were investigated in aqueous phase as the first step. Also, desorption
kinetics of ethanol and water in gaseous phase were investigated. As a result, it was suggested that highly concentrated ethanol
could be obtained with high recovery ratio through these simple operations, meaning the proposed process is quite promising. 相似文献
88.
A synthetic method for bicyclic heterocycles, such as indole, benzofuran and chromene derivatives bearing a chiral cyclopropane at the 2-position, was established using isomerization of a terminal olefin and enamide-ene or diene metathesis. This route can also be applied to chiral 2-cyclopropylquinoline synthesis (both cis and trans). 相似文献
89.
90.
Tue Trong Phan Takaaki Miyasako Koichi Higashimine Eisuke Tokumitsu Tatsuya Shimoda 《Applied Physics A: Materials Science & Processing》2013,113(2):333-338
We propose the use of a La2O3 (LO) film as the capping layer for improvement of a semiconductor/insulator interface in a solution-processed indium–tin–oxide (ITO) ferroelectric-gate thin-film transistor (FGT) device. It is demonstrated that the LO layer acts as a good barrier film not only for preventing the interdiffusion between the ITO semiconductor and lead–zirconium-titanate (PZT) insulator layers, but also for stabilizing the PZT surface structure. The fabricated FGT device exhibited high I on/I off, large M w, high μ FE and improved retention time of about 109, 3.5 V, 7.94 cm2?V?1?s?1 and 1 day, respectively, which are comparable to or better than those obtained with FGTs fabricated by means of conventional vacuum processes. We also point out that the key origin of the interface improvement is likely due to the incorporation of La into the PZT system, forming a La surface-modified PZT system which is more stable than the pure PZT in terms of Pb volatility and formation of oxygen vacancies. 相似文献