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401.
An Oxyma derivative, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl 2-cyano-2-(hydroxyimino)acetate (2), displayed remarkable physicochemical properties as a peptide-coupling additive for peptide-forming reactions in water. Short peptides to oligopeptides could be synthesized by using 2, EDCI, and NaHCO(3) in water without measurable racemization. Significantly, a simple basic and acidic aqueous workup procedure can remove all reagents utilized in the reactions to afford only coupling products in consistently excellent yields. 相似文献
402.
Shin-ichiro Sato Hitoshi Sai Takeshi Ohshima Mitsuru Imaizumi Kazunori Shimazaki Michio Kondo 《Journal of Non》2012,358(17):2039-2043
Electric conductivity variations of undoped, n-type and p-type hydrogenated amorphous silicon (a-Si:H) thin films irradiated with various energy protons are systematically investigated. Dark conductivity (DC) and photoconductivity (PC) of the undoped samples increase at first due to proton irradiation and then decrease dramatically with increasing proton fluence. The increase in DC and PC becomes greater with increased proton energy. However, this increase is metastable and gradually decreases with time at room temperature. Similar results are observed in the n-type a-Si:H, whereas only a monotonic decrease is observed in DC and PC for the p-type samples. The increase of both DC and PC due to proton irradiation is attributed to metastable donor center generation. On further irradiation both the DC and PC decrease by the accumulation of radiation-induced defects, which act as deep traps and compensate carriers. The decrease in DC and PC becomes less pronounced as the proton energy increase and can be fitted along a universal line when the proton fluence is converted into displacement per atom (dpa). 相似文献
403.
Kazuhiro Tsuji Michio Sorai Hiroshi Suga SyÛZÔ Seki 《Molecular Crystals and Liquid Crystals》2013,570(1):71-88
Abstract The heat capacity of the nematogenic liquid crystal, HBAB, has been measured between 15 K and 385 K by using an adiabatic calorimeter. The crystal-crystal phase transition has been discovered at 27 K below the crystal-nematic phase transition temperature. The transition temperatures, the enthalpies and the entropies of the three phase transitions have been determined: T 1 = 306.98 K, ΔH t = 5.11 kJ mol?1, ΔS t = 16.7 JK?l; T m = 334.05 K, ΔH m = 23.77 kJ mol?1, ΔSm = 71.2 J K?l mol?1; and T c = 375.10 K, ΔH c = 1.75 kJ mol?1, ΔS c = 3.2 J K?1 mol?1, respectively. The thermodynamic functions of HBAB from 0 K to 385 K have been determined from the heat capacity data and the enthalpies of the transitions. Two crystal modifications, one yellow and granular form and the other white and needle-like form, have been obtained during the course of the preparation of the sample. It turned out that the yellow form was the stable crystal and the white the metastable modification. The crystal-crystal phase transition has been discussed as an onset of partial melting from the entropy consideration. In this connection the total entropies of the transitions, 91.1 J K?1 mol?1 has been proposed to be an important measure of melting. 相似文献
404.
Michio Yamashita Yoshio Kawai Itsuo Uchida Tadaaki Komori Masanobu Kohsaka Hiroshi Imanaka Kazuo Sakane Hiroyuki Setoi Tsutomu Teraji 《Tetrahedron letters》1984,25(41):4689-4692
The structure elucidation and total synthesis of chryscandin (1), a new antifungal antibiotic produced by No.4629, is reported. 相似文献
405.
406.
The reaction of enamine between 9-chloroacridines and 6-aminouracil derivatives gives the novel acridine substituted uracils, the structure of which has been determined by X-ray crystallography. 相似文献
407.
408.
The action of lithium diisopropylamide on diethyl difluoromethylphosphonate gives the title reagent which reacts with various electrophiles to introduce difluoromethylene or difluoromethyl unit. 相似文献
409.
A bromide salt of a TTF-based cross-cyclophane-type donor displayed characteristic nonlinear voltage-biased conductivity. As the applied voltage was increased, the passing current was enhanced abruptly at 54 kV.cm-1, exhibiting hysteretic behavior. X-ray analysis of the current-induced low-resistance state of the crystal, which has P41 symmetry, revealed that the degree of charge disproportionation of the dimeric donor in the crystal substantially decreased during the current application. This result is interpreted as indicating that the class I mixed-valence state of the cation-radical salt of the dimeric donor was converted into the class III state by the application of the large current. 相似文献
410.