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991.
测量了不同激光功率照射下,在具有不同导热率的三种衬底上蒸镀膜所吸附的C60分子的振动光谱。发现在激光功率达到800mW时,C60分子发生“石墨子”。对石墨化的起因做了定性分析。 相似文献
992.
Joanne DombrowskiSteen Pedersen 《Journal of Mathematical Analysis and Applications》2002,267(2):695-713
We investigate the spectral properties of a class of Jacobi matrices in which the subdiagonal entries are quadratics and the row sums are constants. 相似文献
993.
An exact solution is obtained for the roughness dependent speckle contrast in the case of a rectangular spectrum. This is compared to the simple formula previously obtained for a gaussian spectrum. The agreement is shown to be good if the formulas are fitted to the same asymptotic dependence in the incoherent limit. From this we conclude that the simple gaussian formula may be a useful approximation even for other non-gaussian spectra, and a fitting procedure is indicated. 相似文献
994.
For a C1-dynamical system (A, G, α) we show that the crossed product C1-algebra is induced from a simple C1-algebra equipped with an action of the Connes Spectrum, provided that A is G-simple and all isotropy subgroups of G under the action on the primitive ideal space of A are discrete. We then study the Borchers Spectrum of α and characterize its annihilator in G as the group of locally derivable automorphisms, under the assumption that the Arveson Spectrum of α is compact modulo the Borchers Spectrum. Finally a properly outer automorphism α is characterized by a series of equivalent conditions, one of which says that α is not close to the inner automorphisms on any ideal, another that α is not universally weakly inner on any ideal, and a third that the Borchers Spectrum of α on any invariant hereditary C1-subalgebra is non-zero. This characterization leads to the conclusion that α is aperiodic (i.e., every non-zero power is properly outer) precisely when the Connes Spectrum of α is the full circle group. 相似文献
995.
By showing the existence of certain functions in A+ (the algebraof analytic functions in the unit disc with absolutely convergentTaylor series), we prove that if T is a power bounded operatoron a Banach space X, and x X satisfies Tx x, then
相似文献
996.
采用等体积浸渍法将助剂(MgO、CuO、Co2O3)引入商品Ni-Al合金粉,经10%(w/w)NaOH溶液浸取制备Raney-Ni催化剂。通过能量色散X射线(EDX)、X射线衍射(XRD)、N2吸附-脱附测试、透射电镜(TEM)、NH3程序升温脱附(NH3-TPD)、X射线光电子能谱(XPS)等方法表征和评价实验,考察了金属助剂对Ni-Al合金粉及Raney-Ni催化剂元素组成、晶相结构、孔结构特征、表面形貌、表面酸碱性的影响。表征分析显示,不同助剂催化剂的元素含量、比表面积及表面形貌均表现出明显的差异。其中,添加助剂Cu的催化剂表面检测到较多的活性组分Ni,接近90%(w/w),该催化剂平均孔径最小(3.87 nm)、活性组分Ni颗粒分散性好。评价结果表明,该催化剂具有较佳的加氢性能,其1,4-丁烯二醇(BED)转化率为100%,1,4-丁二醇(BDO)选择性和收率分别为59.62%和59.62%,这与该催化剂较大的活性组分Ni负载量、酸强度和适中的酸量及存在的Cu对Ni分散性的提高进一步防止了Ni的严重烧结(即"限域效应")等有较大关联。 相似文献
997.
K Washington M M Sarasua L S Koehler K A Koehler J A Schultz L G Pedersen R G Hiskey 《Photochemistry and photobiology》1984,40(6):693-701
The interaction of halothane (CF3 CHBrCl) with dipalmitoylphosphatidylcholine (DPPC) membranes containing varying amounts of dipalmitoylphosphatidylglycerol (DPPG) was examined via heavy atom effect quenching of pyrene fluorescence by halothane. The effect of halothane on pyrene fluorescence is consistent with a kinetic model based upon the assumption of the existence of two populations of pyrene in the membrane: one accessible to interactions with halothane; the second inaccessible to halothane on the time scale of the pyrene fluorescence excited state. Both populations of pyrene are affected by the presence of halothane in the membrane. The rate of halothane quenching of pyrene fluorescence is increased significantly for all DPPG/DPPC membranes compared to pure DPPC membranes indicating that any DPPG in the membrane facilitates interaction between halothane and pyrene even though the measured partition coefficients indicate that little change in total halothane concentration in the membrane as a whole occurs as a function of percent DPPG in DPPG/DPPC mixtures.
It is speculated that phase boundaries play an important role in determining the behavior of this model system by determining the location of the pyrene probe. The heavy atom effect quenching of pyrene by halothane provides a useful probe of phase boundaries in membranes. 相似文献
It is speculated that phase boundaries play an important role in determining the behavior of this model system by determining the location of the pyrene probe. The heavy atom effect quenching of pyrene by halothane provides a useful probe of phase boundaries in membranes. 相似文献
998.
S. Bjørnholm J. Borggreen O. Echt K. Hansen J. Pedersen H. D. Rasmussen 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1991,19(4):47-50
Measurements of the mass abundance spectra of sodium clusters containing up to 600 atoms are presented. The clusters are produced in a seeded supersonic expansion of Ar or Kr gas, and the spectra are obtained by a time-of-flight technique. The sawtooth features in the spectra are interpreted as evidence of a regular spherical shell structure with magic numbers,N 0, scaling approximately with the cube root of the number of sodium atoms. Altogether twelve shell closings are observed,N 0=2, 8, 20, 40, 58, 92, 138, 196, 260, 344, 440 and 558. There is also a pronounced odd-even staggering all the way up toN=70. The experimentally observed intensity changes for the clusters around the magic numbers are discussed in terms of the electronic free energy,F(N), calculated at finite temperature, and the second differences of the free energy Δ2 F(N)=F(N?1)?2F(N)+F(N+1). The processes behind the non-uniform abundance distributions, and the thermodynamics of finite electron systems with non-uniform level spacings are discussed on this basis. 相似文献
999.
A new method of determination for roxithromycin tablets by non-aqueous capillary electrophoresis (NACE) with square-wave amperometric detection was carried out. Several parameters affecting the NACE-AD determination were studied. The data was modified by spline wavelet least square (SWLS). The method is simple, rapid and highly reliable for routine analysis. 相似文献
1000.
毛细管电泳安培法测定脂可平胶囊中的姜黄素 总被引:3,自引:3,他引:3
采用毛细管电泳柱端安培检测对脂可平胶囊中的姜黄素进行测定。着重研究了缓冲溶液浓度和酸碱度、检测电位、进样时间和高压对分离测定的影响。以微Pt电极为工作电极,电极电位为 1.0 V,以V(甲醇)∶V(乙醇)∶V(水)=5∶2∶3为非水介质,磷酸二氢钾和硼砂(pH 9.5)为缓冲体系,并用二阶样条小波进行滤波处理,姜黄素在1.0~120 mg/L范围内,峰高与其质量浓度呈良好的线性关系,线性回归方程:Y=20.2 146ρ,检出限为0.02 mg/L。 相似文献