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101.
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104.
Junichi Goto Nobhuharu Goto Atsuko Hikichi Tomoko Nishimaki Toshio Nambara 《Analytica chimica acta》1980
Two highly sensitive, chiral derivatization reagents, D- and L-1-aminoethyl-4-dimethyl-aminonaphthalene, were synthesized from 1-dimethylaminonaphthalene. Condensation of carboxylic acids with the chiral reagent was readily effected in the presence of a watersoluble carbodiimide. The diastereoisomeric amides formed from N-acetylamino acid and α-arylpropionic acid enantiomers were efficiently resolved by normal phase chromatography (μPorasil column) -with hexane/ethyl acetate or hexane/tetrahydrofuran as a mobile phase. With a fluorescence detector (excitation 320 nm, emission 395 nm), the detection limit was 0.1 ng. 相似文献
105.
106.
Intramolecular cyclisation of the trifluoromethanesulphonate esters of the β-(4-hydroxy-n-butyl)-pyrroles (5a) and (5b) in each case yields a mixture of the α- and β-alkylated products whereas exclusive β-alkylation is observed for the β-(5-hydroxy-n-pentyl)-pyrrole (5c). 相似文献
107.
108.
During the course of the study of the hydrothermal stability of alanine oligopeptides, a small amount of oligopeptides longer than the starting oligopeptides was found in the reaction products. On the basis of this unexpected finding and the investigation of the reaction mechanism, the elongation of oligopeptides using (Ala)3, (Ala)4, and (Ala)5 was attempted in aqueous solution at 275-310 degrees C within the second time range using a microflow reactor system. The elongation of (Ala)4 and (Ala)5 succeeded in the presence of an excess amount of Ala monomer. This is probably due to the fact that the elongation rate is competitive or somewhat faster than the degradation of peptide bonding. On the contrary, the elongation of (Ala)3 was not possible since it was immediately converted to diketopiperazine. 相似文献
109.
Yuko?Ogihara Richard?L.?SmithJr.Email author Hiroshi?Inomata Kunio?Arai 《Cellulose (London, England)》2005,12(6):595-606
Direct observations of the heating of microcrystalline cellulose (230 DP) in water at temperatures up to 410 °C and at pressures
up to 700 MPa were made with a batch-type microreactor. Cellulose particles were found to dissolve with water over temperatures
ranging from 315 to 355 °C at high pressures. Dissolution temperatures depended on water density and decreased from about
350 °C at a water density of 560 kg/m3 to a minimum of around 320 °C at a water density of 850 kg/m3. At densities greater than 850 kg/m3, the dissolution temperatures increased and reached a value of about 347 °C at 980 kg/m3. The cellulose dissolution temperatures were independent of heating rates for values ranging from 10 to 17 °C/s. The low
dependence of dissolution temperatures on the heating rates is strong evidence for simultaneous dissolution and reaction of
the cellulose. Different phenomena occurred depending on water density. At low densities, particles turned transparent and
seemed to dissolve into the aqueous phase from the surface. From 670 to 850 kg/m3, the cellulose particles visibly swelled just before completely collapsing and dissolving into the aqueous phase. The swelling
probably increased water accessibility and particle surface area and thus lead to the lower dissolution temperatures observed.
From 850 to 1000 kg/m3, the particles required longer times to dissolve and many fine brown-like particles were generated as the particles dissolved.
FT-IR spectra of the residues were analyzed. Residues formed from heating cellulose at high densities still retained some
cellulose character whereas those as low densities had little cellulose character, especially in the O–H stretching vibration
region. 相似文献
110.
This paper summarizes some hitherto unpublished findings on factors affecting or resulting from social mobility, based on
data obtained from the Social Stratification and Social Mobility Survey conducted in 1955 by the Research Committee of the
Japan Sociological Society.1) Section I is concerned with factors related to inter-generation occupational mobility, Section II with inter-generation educational
mobility, and Section III with occupational mobility within the individual’s lifetime. In additon, in Section IV relations
between social mobility and respondent’s attitudes will be dealt with. 相似文献