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101.
102.
Eu1—xTbxBa2Cu3O7—δ中Tb离子价态的研究 总被引:1,自引:0,他引:1
研究了BaTbO_3、Tb_4O_7、TbFeO_3的Tb_(4d)XPS谱,找到了表征Tb~(3+)、Tb~(4+)的特征峰,得出的高、低结合能峰强之比与Tb~(4+)/Tb含量间的依赖关系,可用于确定Eu_(1-x)Tb_xBa_2Cu_3O_(7-δ)中“123”相的Tb离子混合价态,用常压高温烧结法,未能获得纯“123”单相,也不易获得纯利Tb~(3+)价态样品.在Eu_(1-x)Tb_xBa_2Cu_3O_(7-δ)中的Tb以Tb~(3+)、Tb~(4+)混合价态存在;当x=0.3时,Tb~(4+)/Tb=0.61.引入Tb~(4+)后“123”主相Cu(2)-O(2)平面上的O_(2p)空穴数降低,这是Tb~(4+)破坏超导电性的一种可能原因。 相似文献
103.
聚乙烯塑料在连续超临界水反应器中的油化研究 总被引:1,自引:1,他引:1
在连续超临界水(SCW)反应器中考察了反应温度、停留时间和反应压力对聚乙烯(PE)降解油化的影响。实验结果表明,在120s、25MPa下,从500℃提高到550℃,液体收率呈现先升后降的趋势,在530℃达到最大值(79%);在520℃、25MPa下,随停留时间的延长,PE裂解程度加深,产物轻质化程度提高,导致液体收率降低,停留240s时,气体收率达到43%;反应压力对产物收率的影响较小,气、液产物中烯/烷比随反应压力的增加而增大。 相似文献
104.
FTIR-ATR has been used for understanding the interaction between bacteria and surfaces in the adsorption progress. 相似文献
105.
采用浸渍法,制备了用于合成吲哚的Cu/SiO2催化剂,研究了不同载体和活性组分Cu对苯胺和乙二醇一步合成吲哚反应的催化活性,发现γ-Al2O3、活性炭、Na-Y,SiO2-MgO、MCM41、SiO26种载体中,SiO2是最好的载体;催化剂活性组分Cu含量为0.78mmol/gSiO2时,吲哚的收率高达88%,考察了水蒸汽、氢气、反应温度及接触时间等因素对反应性能的影响,并对催化剂进行了TG测试,得到了Cu/Sio2催化剂催化合成吲哚适应反应条件。 相似文献
106.
Ionization and dissociation of nitrosyl chloride ClNO were studied using femtosecond laser mass spectra tech-nique.Strong fragmental ions NO~ and Cl~ were observed with the laser intensity varied from 3.2×10~(14) to 2.5×10~(15) W/cm~2.These fragmental ions were attributed to the direct dissociation of the parent ions.Electronic structurecalculations were also carried out with Hartree-Fock,density functional and correlated levels of theory to under-stand the possible fragmentation pathways.The very low N-Cl bond energy in the parent ion of nitrosyl chloride isa clear reason for the absence of ClNO~ and ClN~ ion peaks from the femtosecond laser mass spectrum. 相似文献
107.
108.
The exact residues within severe acute respiratory syndrome coronavirus (SARS-CoV) S1 protein and its receptor, human ACE2, involved in their interaction still remain largely undetermined. Identification of exact amino acid residues that are crucial for the interaction of S1 with ACE2 could provide working hypotheses for experimental studies and might be helpful for the development of antiviral inhibitor. In this paper, a molecular docking model of SARS-CoV S1 protein in complex with human ACE2 was constructed. The interacting residue pairs within this complex model and their contact types were also identified. Our model, supported by significant biochemical evidence, suggested receptor-binding residues were concentrated in two segments of S1 protein. In contrast, the interfacial residues in ACE2, though close to each other in tertiary structure, were found to be widely scattered in the primary sequence. In particular, the S1 residue ARG453 and ACE2 residue LYS341 might be the key residues in the complex formation. 相似文献
109.
Xing Yong Wang Jing Nan Cui Wei Min Ren Feng Li Chun Liang Lu Xu Hong Qian State Key Laboratory of Fine Chemicals Dalian University of Technology Dalian China School of Chemical Engineering Technology China University of Mining & Technology Xuzhou China Shanghai Key Laboratory of Chemical Biology East China University of Science Technology Shanghai China 《中国化学快报》2007,18(6):681-684
Baker's yeast mediated reduction of acenaphthenequinone within 4-10 h afforded mono-hydroxyacenaphthenone mainly with low enantioselectivity, the substrate and mono-hydroxyacenaphthenone product almost converted to dihydroxyacenaphthene after 48 h. By control of the reaction time and in the presence of DMF as co-solvent, the reduction of 6-substituted acenaphthenequinones under vigorous agitation afforded the corresponding 2-hydroxyacenaphthenones in 24-84% yields with 10-93% ee. 相似文献
110.
Cheng-Zhu Wu Xing Fu Cai Seong Su Hong Eun-Kyoung Seo Ji-Xing Nan Jung Joon Lee 《Tetrahedron letters》2007,48(50):8861-8864
Two novel dimeric meroterpenoids, bisbakuchiols A and B, along with (S)-bakuchiol were isolated from the seeds of Psoralea corylifolia L. (Fabaceae). Bisbakuchiols A and B contain an unprecedented dimeric meroterpenoid skeleton in which two meroterpenes are linked through a dioxane bridge. All compounds were evaluated for their potential to inhibit hypoxia-inducible factor-1 (HIF-1) activation induced by hypoxia in a HIF-1-mediated reporter gene assay in AGS human gastric cancer cells. (S)-Bakuchiol inhibited hypoxic activation of HIF-1 with an IC50 value of 6.1 μM. 相似文献