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951.
Zhong Jie ZOU Yue Sheng DONG Jun Shan YANG 《中国化学快报》2005,16(11):1484-1486
A new β-carboline alkaloid, 4-(9H-β-carbolin-1-yl)-4-oxobutyric acid and a new derivate of isoferulic acid, (E)-3-(3-hydroxy-4-methoxyphenyl)acrylic acid carboxymethyl ester, were isolated from the roots of Anemone altaica. Their structures were determined on the basis of spectral data. 相似文献
952.
晶态氮化碳薄膜的低温合成 总被引:1,自引:0,他引:1
The synthesis of carbon nitride films at low temperature has been investigated using pulsed arc discharge from methanol solution with nitrogen atmosphere. Raman spectra and X-ray diffraction (XRD) analysis suggest that crystalline carbon nitride films may be prepared at low substrate temperature (220 ℃). At same time, the substrate temperature has a significantly effect on the nitrogen content and structure of the films. Increasing substrate temperature (300 ℃) would decrease the content of nitrogen in the films and result in a formation of carbon films. 相似文献
953.
Xi Cun WANG Zheng Jun QUAN Man Gang WANG Zheng LI 《中国化学快报》2005,16(8):1027-1030
Eighteen 1-aroyl-4-(2-iodobenzoyl)thiosemicarbazides and corresponding semicarbazides were synthesized in excellent yield under microwave irradiation in solvent and catalyst free condition. 相似文献
954.
Phosphonium or arsonium salt 1 can undergo the tandem reaction of deprotonation -oxidation-Wittig reaction with alcohol 2 in the presence of sodium hydroxide and manganese dioxide,which affords a general simplified method for the stereoselective synthesis of (E)- α-β-unsaturated esters 3. 相似文献
955.
使用PAN-Ni(Ⅱ)共沉淀体系分离富集、微量流向进样火焰原子吸收光谱测定饮水和人发中的微量锰。样品中的共存元素不干扰测定,锰的标准加入回收率90%-108%之间。12次重复测定锰含量为0.15μg/mL的试样溶液的变异系数为4.6%,本法简便快捷,取得了较满意的结果. 相似文献
956.
This paper presents the synthesis of some novel acyclonucleosides containing 2‐pyridinones and 2‐hydroxyethoxymethyl, 2,3‐dihydroxy‐propyl side chain. The tosylate of these nucleosides analogues could be modified to azido derivatives. Also, acyclonucleosides with 1‐ethoxymethyl, 1‐benzyloxymethyl, 1‐methylthiomethy 1 and 2‐hydroxyethyl side chains have been investigated. The O‐alkylated pyridine derivatives were obtained during most reactions. 相似文献
957.
Yu Ping ZHANG Wen Jun GONG Li Qun FAN Yi Jun ZHANG Kwang Pill LEE 《中国化学快报》2006,17(11):1485-1488
A porous monolithic sol-gel column with the solution of methacryloxypropyltrimethoxysilane in toluene with an acid catalyst was prepared in the presence and absence of sodium dodecyl sulfate. In situ polymerization was carried out byγ-ray irradiation within the capillary. Theγ-radiation-initiated synthesis could generate radicals directly on the monomer avoiding use of any initiator. The chromatographic behavior of the capillary monolithic columns were studied in the modes of CEC, p-CEC and low pressure-driven separation, all the tests exhibited reversed-phase character. It provided a viable alternative to either thermally initiated or photo polymerization method for the preparation of monolithic columns. 相似文献
958.
959.
960.
Masayoshi Nakasako Masamitsu Wada Satoru Tokutomi Kotaro T. Yamamoto Jun Sakai Mikio Kataoka Fumio Tokunaga † Masaki Furuya 《Photochemistry and photobiology》1990,52(1):3-12
Abstract— The quaternary structure of pea phytochrome type I (PI) dimer in the red-light-absorbing form was studied by small-angle X-ray scattering (SAXS) technique and rotary-shadowing electron microscopy. Structural parameters for PI 114 kDa chromopeptide dimer and its tryptically digested N-terminal 59 kDa chromopeptide monomer, such as average electron density, molecular volume and the second moment of electron density distribution, were determined in terms of SAXS using the contrast variation method. Furthermore, by means of model simulation for the scattering profiles of the chromopeptides, most plausible structural models for both peptides were constructed. The distance between the chromophoric domains was estimated to be about 70 A in the resultant model for 114 kDa chromopeptide dimer. Furthermore, the model was consistent with the electron-micrographic images of both the intact PI dimer and the PI 114 kDa chromopeptide dimer, so that the N-terminal 7 kDa fragment did not significantly contribute the low-resolution images of the dimer. 相似文献