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11.
Xu Jie-Cheng Cheng Ling-Ling Shen Wei-Zhen Wang Shi-Qing Qian Cui-He Huang Jia-Xin 《中国化学》1986,4(2):160-167
DSIP and its fourteen analogs as well as three short peptides were synthesized by solid phase method. The design of the analogs was based on the consideration of the introduction of D-amino acid into the molecules to inhibit the enzymatic hydrolysis and the introduction of amino acids with a hydrophobic side chain. The modification was placed on the position of 1, 3, 4, 5, 8 and 9, e.g. D- Trp1, Tyr1, Tyr1 Phe5, D-Trp1 Phe8, Trp3,4, D-Trp1,3,4 Phe8, D-Trp3,4 Phe8 D-Glu9, D-pF-Phe3,4 Phe8 D-Glu9, Phe5, Glu5 Asp9, Tyr6 Asp9, Asp9 and Ala7-DSIP as well as Trp-Ala-Gly-Gly-Asp, Trp-Ala-Gly-Gly-Glu and Trp-Gly-Glu. DSIP and Phe5-DSIP were also prepared by pentafluorophenyl ester method. The purity of the synthetic peptides was checked by amino acid analysis, elemental analysis, thin layer chromatography and paper electrophoresis. The biological assay showed that the analogs of D-Trp1, Tyr1, Tyr1 Phe5 and Ala7-DSIP as well as three short peptides were inactive whereas Phe5-DSIP showed similar activity as that of synthetic DSIP. 相似文献
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通过两步法制备了一种空心六边形镍钴硫化物(HHNCS)与还原氧化石墨烯(RGO)的纳米复合材料HHNCS/RGO。利用XRD,SEM,TEM和Raman光谱等对复合物进行表征,发现镍钴硫化物为空心六边形结构,并且均匀地附着在RGO的表面。该纳米复合物用作超级电容器电极表现出优异的电化学性能。在电流密度为1 A·g-1时比电容为927 F·g-1;当电流密度增大到20 A·g-1时,比电容仍高达724 F·g-1,表明材料拥有较好的倍率性能。此外,在电流密度5 A·g-1下循环2 000次后比电容保留有初始值的93%,显示出优异的循环稳定性。HHNCS/RGO优异的电容性能主要是由于RGO的存在不仅增强了材料的导电性,而且作为理想的载体分散HHNCS纳米片。HHNCS/RGO纳米复合物优异的电化学性能使其在超级电容器电极材料领域具有应用前景。 相似文献
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采用基于密度泛函理论框架下的第一性原理平面波超软赝势方法,结合局域密度近似(LDA)研究了钙钛矿结构氧化物LaAlO3/SrTiO3界面的电子结构及光学性质.能带结构分析表明当形成(AlO2)-/(TiO2)0界面时其禁带宽度为1.888 eV,呈现绝缘体的性质,当形成(LaO)+/(SrO)0界面时其禁带宽度为0.021eV,呈现半导体或半金属性质.同时,对不同界面的光学性质也进行了研究,结果表明纯相的LaAlO3和SrTiO3的吸收系数、反射系数及能量损失谱强度明显高于由这两种单质形成不同界面的强度. 相似文献
16.
Host dependent thermal stability and frequency upconversion of Er^3+-doped heavy metal oxyfluoride germanate glasses
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The upconversion properties of Er^3+-doped heavy metal oxyfluoride germanate glasses under 975 nm excitation have been investigated. The intense green (551 and 529 nm) and relatively weak red (657 nm) emissions corresponding to the transitions ^4S3/2→^4I15/2, ^2H11/2→^4 I15/2 and ^4F9/2 →^4I15/2, respectively, were simultaneously observed at room temperature. The content of PbF2 has an important influence on the upconversion luminescence emission. With increasing content of PbF2, the intensities of green (529 nm) and red (657 nm) emissions increase slightly, while the green emission (551 nm) increases markedly. These results suggest that PbF2 has an influence on the green (551 nm) emission more than on the green (529 nm) and red (657 nm) emissions. 相似文献
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研究了卤化铅调整Tm3+/Yb3+共掺碲酸盐玻璃的热稳定性能、Raman 光谱和上转 换发光光谱,分析了Tm3+/Yb3+共掺氧卤碲酸盐玻璃的上转换发光 机理.结果发 现:混合卤化铅调整Tm3+/Yb3+共掺碲酸盐玻璃具有好的热稳定性 能、低的声 子能量、强的上转换蓝光.这表明混合卤化铅调整Tm3+/Yb3+共掺碲 酸盐玻璃是一种上转换蓝光激光器的潜在基质材料.
关键词:
氧卤碲酸盐玻璃
上转换光谱
发光机理
上转换蓝光激光器 相似文献
18.
Simple schemes for generation of W-type multipartite entangled states and realization of quantum- information concentration
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We propose simple schemes for generating W-type multipartite entangled states in cavity quantum electrodynamics (CQED). Our schemes involve a largely detuned interaction of Λ-type three-level atoms with a single-mode cavity field and a classical laser, and both the symmetric and asymmetric W states can be created in a single step. Our schemes are insensitive to both the cavity decay and atomic spontaneous emission. With the above system, we also propose a scheme for realizing quantum-information concentration which is the reverse process of quantum cloning. In this scheme, quantum-information originally coming from a single qubit, but now distributed into many qubits, is concentrated back to a single qubit in only one step. 相似文献
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Effects of Anisotropy on Entanglement in a Two-Qubit Heisenberg XYZ Chain with Intrinsic Decoherence
XIE Li-Jun ZHANG Deng-Yu TANG Shi-Qing ZHANG Xiao-Gui GAO Feng 《理论物理通讯》2009,51(4):659-663
Taking the intrinsic decoherence effect into account, the entanglement ofa two-qubit anisotropic Heisenberg XYZ chain in the presence of the Dzyaloshinski Moriya (DM) anisotropic antisymetric interaction is investigated in this paper. Concurrence, the measurement of entanglement, is calculated. Compared with the anisotropic in XY plane, the DM interaction is another kind of anisotropic antisymmetrie exchange interaction. It is shown that the intrinsic decoherence obviously suppresses the time evolution of the entanglement. The DM interaction only acts on the time evolution of the entanglement when the initial state is [ψ(0)〉 = cosα|01〉 + sinα|10〉 and weakens the degree of entanglement. The anisotropic in XY plane merely impacts on the time evolution of the entanglement when the system & initially in a state |ψ(0)〉 = cos α|00〉 + sin α|11 〉. The sufficiently weak anisotropic in XY plane can effectively enhance the degree of entanglement. 相似文献