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E. Iritani N. Katagiri T. Sengoku K.M. Yoo K. Kawasaki A. Matsuda 《Journal of membrane science》2007,300(1-2):36-44
The properties of dead-end microfiltration were explored under constant pressure using two types of activated sludge controlled under the condition of different air flow rates. The activated sludge cultured at the air flow rate of 0.15 L min−1 (the anaerobic condition) exhibited a significant flux decline compared with the case of the air flow rate of 2.33 L min−1 (the aerobic condition). It was found from the results of microfiltration of the supernatant separated by centrifugation that the constituents in the supernatant caused a major cake resistance in microfiltration of the activated sludge. The average specific filtration resistance for filtration of the activated sludge was closely consistent with that for filtration of the supernatant at low pressure (49 kPa). However, the cake resistance of the microbial floc in microfiltration of the activated sludge became substantial with increasing filtration pressure because of high compressibility of the microbial floc. Moreover, the foulant and the fouling mechanism in microfiltration of the supernatant were evaluated from both microfiltration test of the supernatant and microfiltration test of the filtrate collected thereby. As a result, the effects of the pore size and material of the microfiltration membrane on the flux decline behaviors in dead-end microfiltration were reasonably elucidated. 相似文献
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Total Synthesis of the Antibiotic Kendomycin: A Macrocyclization Using the Tsuji–Trost Etherification
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Dr. Tetsuya Sengoku Dr. Shu Xu Kenji Ogura Yoshinori Emori Kenji Kitada Prof. Dr. Daisuke Uemura Prof. Dr. Hirokazu Arimoto 《Angewandte Chemie (International ed. in English)》2014,53(16):4213-4216
A highly stereocontrolled, convergent total synthesis of kendomycin [(?)‐TAN2162], an ansa‐macrocyclic antibiotic, is reported. The key of the strategy is an unprecedented Tsuji–Trost macrocyclic etherification, followed by a transannular Claisen rearrangement to construct the 18‐membered carbocyclic framework. The oxa‐six‐ and five‐membered rings were also stereoselectively constructed respectively by a cascade oxidative cyclization at an unfunctionalized benzylic position and using a one‐pot epoxidation/5‐exo‐tet epoxide opening. 相似文献
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[reaction: see text] Enantioselective synthesis of attenols A and B was accomplished by using diastereoselective hydroboration, Lindlar reduction, and acid-catalyzed acetal formation. 相似文献
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Ikuko Mori Miyuki Ukachi Kimiyo Nagano Hiroyasu Ito Jun Yoshinaga Masataka Nishikawa 《Analytical and bioanalytical chemistry》2010,397(2):463-470
A candidate environmental certified reference material (CRM) for the determination of multielements in tea leaves and materials
of similar matrix, NIES CRM No. 23 Tea Leaves II, has been developed and characterized by the National Institute for Environmental
Studies (NIES), Japan. The origin of the material was tea leaves, which were ground, sieved through a 106-μm mesh, homogenized,
and then subdivided into amber glass bottles. The results of homogeneity and stability tests indicated that the material was
sufficiently homogeneous and stable for use as a reference material. The property values of the material were statistically
determined based on chemical analyses by a network of laboratories using a wide range of methods. Sixteen laboratories participated
in the characterization, and nine certified values and five reference values were obtained. These property values of the candidate
CRM, which are expressed as mass fractions, were close to the median and/or mean values of the mass fractions of elements
in various tea products. The candidate CRM is appropriate for use in analytical quality control and in the evaluation of methods
used in the analysis of tea and materials of similar matrix. 相似文献
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When a mixture of o-alkynylaryl isocyanides and organic dichalcogenides such as diselenides or ditellurides was irradiated with light of wavelength over 300 or 400 nm, the intramolecular cyclization of the isocyanides took place to afford the corresponding 2,4-bischalcogenated quinolines selectively. The photochemical cyclization of 2-(phenylethynyl)phenyl isocyanide could also proceed in the presence of hydrogen transfer reagents such as tris(trimethylsilyl)silane, tributylgermyl hydride, alkanethiols, and benzeneselenol, providing the corresponding 3-phenylquinoline as the result of 2,4-dihydrogenation. 相似文献
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The critical dose for extinction of the diffraction pattern from behenic acid monolayer crystals increased with increasing accelerating voltages. The mean values at 114, 500 and 1000kV were 0.6, 1.8 and 2.2 electrons/A(2), respectively. The critical dose at 500-1000kV is three or more times as large as that at 114kV. Considering this with the recent measured value of the detective quantum efficiency of the image plate, 0.5 at 500kV and 0.4 at 1000kV, 1.5 times as much information can be collected from a crystal at 500-1000kV as at 114kV. Therefore, the combined use of high voltage electron microscopy and image plate detectors offers a significant improvement over conventional electron microscopy approaches for the study of radiation sensitive organic molecule crystals. 相似文献
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Iwao Ojima Mitsuru Nihonyanagi Tetsuo Kogure Miyoko Kumagai Shuji Horiuchi Kimiyo Nakatsugawa Yoichiro Nagai 《Journal of organometallic chemistry》1975,94(3):449-461
The hydrosilylation of various carbonyl compounds such as simple aldehydes, simple ketones, α,β-unsaturated carbonyl compounds, α-diketones, acyl cyanides and ketones having an electron-withdrawing group on the α-carbon using tris(triphenylphosphine)chlororhodium as a catalyst is described. Solvolysis of these silyl ethers and silyl enol ethers afforded the corresponding reduced products. The hydrosilylation of α,β-unsaturated carbonyl compounds was found to proceed by 1,4-addition. An oxidative adduct of triethylsilane to the rhodium-(I) complex was obtained as a reaction intermediate. The structure of the adduct was discussed on the basis of its IR and far-IR spectra. 相似文献
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Fine perylene and pyrene particles were produced by evaporation in helium gas. The particles were sensitive to electron beam radiation. The pyrene particles sublimed under observation. These difficulties were cleared up by reducing electron beam exposure and sandwiching a specimen between two Formvar films. The fine perylene particles were rectangular or hexagonal plates about 50nm thick. The size was about 200-2000nm. The fine pyrene particles were polymorphic with a size of about 300-2000nm. The crystal forms of the perylene and pyrene particles were determined from the electron diffraction patterns to be alpha-perylene and pyrene I, respectively. 相似文献
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Akira Okada Satoshi Yokojima Noriyuki Kurita Yasuo Sengoku Shigenori Tanaka 《Journal of Molecular Structure》2003,630(1-3):283-290
A theory for charge transfer between the electrode and the donor/acceptor molecule coupled through a DNA bridge in solution is developed. We explore the crossover between the coherent tunneling and the incoherent sequential transfer regimes by varying the electrode potential and discuss the effects of single-base mismatches in DNA duplex in both regimes. In the former regime a single-base mismatch in DNA duplex causes a reduction in the charge transfer rate simply by decreasing the electron tunneling matrix element, however, in the latter regime the effects are rather complicated. 相似文献