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911.
Electrons with an energy of 300 keV or lower were defined as “Soft-electrons”, which showed several advantages over conventional irradiation with gamma-rays or high-energy electrons in decontamination of grains and spices. Energies of electrons necessary to reduce microbial loads to levels lower than 10 CFU/g were 60 keV for brown rice, 75 keV for wheat, 100 keV for white pepper, coriander and basil, 130 keV for buckwheat, 160 keV for rough rice, and 210 keV for black pepper. Electrons with such energies did not significantly influence the quality. 相似文献
912.
[reaction: see text] A variety of selenoiminium salts were obtained by reacting the corresponding selenoamides with methyl triflate at room temperature for 30 s. All of the salts were stable under air. The structures of the selenoiminium salts were determined by X-ray molecular analysis. An aromatic selenoiminium salt reacted with BuLi (3 equiv) to give two types of ketones. In a reaction with LiAlH(4)/Te, the selenoiminium salts were converted to telluroamides. 相似文献
913.
Mitsuru ShojiSatoshi Kishida Yusuke KoderaIsamu Shiina Hideaki KakeyaHiroyuki Osada Yujiro Hayashi 《Tetrahedron letters》2003,44(38):7205-7207
Of the 16 possible modes of the oxidation-6π-electrocylization-Diels-Alder reaction cascade for an epoxyquinone, and eight for a 2-alkenyl-3-hydroxymethyl-2-cyclohexen-1-one, only the endo-anti(epoxide)-anti(Me)-hetero and endo-anti(Me)-hetero are respectively observed, while both the endo-anti(epoxide)-anti(Me)-hetero and exo-anti(epoxide)-anti(Me)-homo reaction modes occur with epoxy-4-hydroxycyclohexenones owing to a hydrogen-bonding interaction. 相似文献
914.
A sensitive method was developed for the determination of deuterated and non-deuterated 1-methyl-1,2,3,4-tetrahydro-beta-carboline by combined capillary gas chromatography and negative-ion chemical ionization mass spectrometry. 1-Methyl-1,2,3,4-tetrahydro-beta-carboline was converted into a trifluoroacetyl derivative after pretreatment with fluorescamine and extraction with ethyl acetate. The derivative was separated by capillary gas chromatography and determined by selected-ion monitoring. In the determination, [3,3,4,4-2H4]-1-methyl-1,2,3,4-tetrahydro-beta-carboline was used as an internal standard. The method developed in this work was used for the determination of deuterated and non-deuterated 1-methyl-1,2,3,4-tetrahydro-beta-carboline in human urine samples collected before and after administration of [3,3-2H2]-L-tryptophan. 相似文献
915.
The tetramer of octaethylporphyrin nickel complex [OEP(Ni)], connected with diacetylene and ethylene linkages, was synthesized. Its structural and electronic properties were studied, proving that two constituents of the diacetylene-group connected OEP(Ni) dimer face to each other in s-cis conformation about the ethylene linkage but not so closely as to induce a transannular π-electronic interaction between them. 相似文献
916.
Y. Tabata H. Kobayashi M. Washio Y. Yoshida N. Hayashi S. Tagawa 《Journal of Radioanalytical and Nuclear Chemistry》1986,101(2):163-169
A new picosecond pulse radiolysis Twin LINAC System has been constructed recently at Nuclear Engineering Research Laboratory at the University of Tokyo. The time resolution of the system is 20 ps and the system has a versatile capability for pulse radiolysis study. The outline of the facility is introduced. Some research carried out using the facility is presented. The examples are radiolysis of CCl4 and n-C21H44. 相似文献
917.
Eiji Hayashi Takashi Abe Hajime Baba Shunji Nagase 《Journal of fluorine chemistry》1984,26(4):417-434
Electrochemical fluorinations of six kinds of N-(ω-chloroalkyl)pipecolines [N-(2-chloroethyl)-2-, N-(3-chloropropyl)-2-, N-(2-chloroethyl)-3-, N-(3-chloropropyl)-3-, N-(2-chloroethyl)4- and N-(3-chloropropyl)-4-pipecolines] and two kinds of N-(ω- chloroalkyl)-substituted hexamethyleneimines [N-(2-chloroethyl)- and N-(3-chloropropyl)hexamethyleneimines] were conducted. From these starting materials, corresponding chlorine-retained fully fluorinated amines together with ring isomerized products were formed in yields of 7.6~14.8% from the former and 5.4~5.5% from the latter, respectively. New chloropolyfluoroamines obtained in the present investigation have been isolated and characterized by spectroscopic (infrared, 19F nmr and mass) and elemental analysis. 相似文献
918.
A stereocontrolled total synthesis of both the (+)- and (-)-epolactaene ((+)- and (-)-1) enantiomers from tetrahydropyran-2-ol is described. The following reactions in this synthesis are particularly noteworthy: (1) the stereoselective construction of the conjugated (E,E,E)-triene by a combination of kinetic deprotonation and thermodynamic equilibration, (2) the E-selective Knoevenagel condensation of beta-ketonitrile 33 with a chiral 2-alkoxyaldehyde, (3) a diastereoselective epoxidation achieved using a bulky nucleophile (TrOOLi) and an appropriate protecting group, (4) the mild hydrolysis of an alpha-epoxy nitrile by silica gel on TLC facilitated by hydroxyl-mediated, intramolecular assistance. 相似文献
919.
Myers MC Witschi MA Larionova NV Franck JM Haynes RD Hara T Grajkowski A Appella DH 《Organic letters》2003,5(15):2695-2698
[structure: see text] A strategy to restrict the highly flexible backbone conformation of a peptide nucleic acid (PNA) by incorporation of a cyclopentane ring is proposed. An asymmetric synthesis of cyclopentane-modified PNA is reported, and its binding properties were determined. The cyclopentane ring leads to a significant improvement in the binding properties of the resulting PNA to DNA and RNA. 相似文献
920.
Naoki Shinozaki Ryoji Takahashi Satoshi Sato Toshiaki Sodesawa 《Journal of Sol-Gel Science and Technology》2007,43(3):275-282
The bending strength and the Young’s modulus of bimodal porous silica gels having different porosity were evaluated. The porosity
of the gel increased by aging the gel under basic conditions, and decreased with increasing the calcination temperature. The
mesopores disappeared on calcination at 1,050 °C, whereas continuous macropores retained their morphology up to 1,050 °C for
all the samples. Both the bending strength and the Young’s modulus of the bimodal porous silica gels were expressed as power-law
functions of the bulk density, and no effect of bimodal pore structures on mechanical properties was observed. We also found
linear correlation between the bending strength and the elasticity. The bimodal porous silica had higher strength and elastic
modulus compared with other porous materials at the same porosity probably due to the presence of homogeneous micrometer-scale
macropores. 相似文献