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81.
郑其 《通信业与经济市场》2006,(2):48-50
“缘订全球通,今生永相随”,这是中国移动关于全球通业务的宣传语。不过,因为参与四川移动对全球通用户推出的一项活动,家住成都四圣祠北街的代女士却感到很受伤。2月23日,代女士向笔者表示,她对现在手上这款参加四川移动活动得到的索爱W550C手机头疼至极。 相似文献
82.
提出水冷式双压电晶片自适应铜镜和钼镜以补偿输出功率高达15KW激光系统的大规模光学象差,报道所研制的水冷式双压电晶片反射镜特性的研究结果,实验结果和计算机模拟结果进行了比较。提出和讨论了双压电晶片面前途的设计方案。 相似文献
83.
Yurkin MA Semyanov KA Tarasov PA Chernyshev AV Hoekstra AG Maltsev VP 《Applied optics》2005,44(25):5249-5256
Elastic light scattering by mature red blood cells (RBCs) was theoretically and experimentally analyzed by use of the discrete dipole approximation (DDA) and scanning flow cytometry (SFC), respectively. SFC permits measurement of the angular dependence of the light-scattering intensity (indicatrix) of single particles. A mature RBC is modeled as a biconcave disk in DDA simulations of light scattering. We have studied the effect of RBC orientation related to the direction of the light incident upon the indicatrix. Numerical calculations of indicatrices for several axis ratios and volumes of RBC have been carried out. Comparison of the simulated indicatrices and indicatrices measured by SFC showed good agreement, validating the biconcave disk model for a mature RBC. We simulated the light-scattering output signals from the SFC with the DDA for RBCs modeled as a disk-sphere and as an oblate spheroid. The biconcave disk, the disk-sphere, and the oblate spheroid models have been compared for two orientations, i.e., face-on and rim-on incidence, relative to the direction of the incident beam. Only the oblate spheroid model for rim-on incidence gives results similar to those of the rigorous biconcave disk model. 相似文献
84.
We report a new approach in optical coherence tomography (OCT) called full-field Fourier-domain OCT (3F-OCT). A three-dimensional image of a sample is obtained by digital reconstruction of a three-dimensional data cube, acquired with a Fourier holography recording system, illuminated with a swept source. We present a theoretical and experimental study of the signal-to-noise ratio of the 3F-OCT approach versus serial image acquisition (flying-spot OCT) approach. 相似文献
85.
We built a transient absorption spectrophotometer that can determine transient absorption spectral changes that occur at times as fast as approximately 200 ns and as slow as a minute. The transient absorption can be induced by a temperature-jump (T-jump) or by optical pumping from the deep ultraviolet (UV) to the infrared (IR) by use of single ns Nd:YAG laser pulses. Our use of a fiber-optic spectrometer coupled to a XeF flashlamp makes the collection of transient spectra easy and convenient in the spectral range from the near IR (1700 nm) down to the deep UV (200 nm), with high signal-to-noise (S/N) ratios. The spectral resolution is determined by the specific configuration of the fiber-optic spectrometer (grating groove density, fiber diameter, slit width) and varies between 0.3 and 10 nm. The utility of this spectrometer was demonstrated by measuring the rate at which a polymerized crystalline colloidal array (PCCA) of poly(N-isopropylacrylamide) nanogel particles optically switch light due to a T-jump induced by nanosecond 1.9 microm laser pulses. In addition, we measured the rate of optical switching induced by a 3 ns 355 nm pump pulse in PCCA functionalized with azobenzene. 相似文献
86.
Multilayer mirrors capable of > 99.9% reflectivity in the far infrared (70-200 microm wavelengths) were constructed using thin silicon etalons separated by empty gaps. Calculations indicate that only three periods are required to produce 99.9% reflectivity because of the large difference between the index of refraction of silicon (3.384) and the vacuum (1). The mirror was assembled from high-purity silicon wafers, with resistivity over 4000 omega cm to reduce free-carrier absorption. Wafers were double-side polished with faces parallel within 10 arc sec. The multilayer mirror was demonstrated as a cavity mirror for the far-infrared p-Ge laser. Dependence of reflectivity on design accuracy was considered. 相似文献
87.
High-sensitivity ion mobility spectrometry/mass spectrometry using electrodynamic ion funnel interfaces 总被引:1,自引:0,他引:1
Tang K Shvartsburg AA Lee HN Prior DC Buschbach MA Li F Tolmachev AV Anderson GA Smith RD 《Analytical chemistry》2005,77(10):3330-3339
The utility of ion mobility spectrometry (IMS) for separation of mixtures and structural characterization of ions has been demonstrated extensively, including in biological and nanoscience contexts. A major attraction of IMS is its speed, several orders of magnitude greater than that of condensed-phase separations. Nonetheless, IMS combined with mass spectrometry (MS) has remained a niche technique, substantially because of limited sensitivity resulting from ion losses at the IMS-MS junction. We have developed a new electrospray ionization (ESI)-IMS-QTOF MS instrument that incorporates electrodynamic ion funnels at both front ESI-IMS and rear IMS-QTOF interfaces. The front funnel is of the novel "hourglass" design that efficiently accumulates ions and pulses them into the IMS drift tube. Even for drift tubes of 2-m length, ion transmission through IMS and on to QTOF is essentially lossless across the range of ion masses relevant to most applications. The rf ion focusing at the IMS terminus does not degrade IMS resolving power, which exceeds 100 (for singly charged ions) and is close to the theoretical limit. The overall sensitivity of the present ESI-IMS-MS system is comparable to that of commercial ESI-MS, which should make IMS-MS suitable for analyses of complex mixtures with ultrahigh sensitivity and exceptional throughput. 相似文献
88.
The initial stage of the reaction between sodium stearate (NaSt) and AgNO(3) produces silver stearate (AgSt) micelles, [(C(18)H(35)O(2))(x)(Na(x-y))(Ag(y))(H(2)O)(z)], and aggregations of these AgSt micelles in the form of cubic pre-AgSt crystals. When cubic grains of 50?nm AgBr are added to the NaSt dispersion prior to the AgNO(3), the reaction proceeds to form the silver stearate micelles, but not the aggregation of those micelles. Instead, the {111} silver ion planes of the cubic AgBr crystal corners provide nucleation sites for silver stearate micelle deposition and crystal growth. After nucleation, the AgSt micelles evolve into nanostructured bud-like formations via an epitaxial interface on one or several corners of each AgBr cubic crystal. Over time, additional AgSt micelle deposition enables the buds to grow longer into strand-like structures, which then connect to form the beginnings of the ultimate silver stearate crystal plates. 相似文献
89.
It was found that the including of nutritional formulae in the dietary therapy for patients with cardiovascular diseases and obesity has been evaluated, had a positive effect on the clinical presentation of disease, lipid metabolism and the dynamic of body composition of patients. 相似文献
90.
The investigation of influent of antiatherosclerotic diets with chitosan on clinical and metabolic parameters in patients with cardiovascular diseases. Results of the study show that enrichment of a diet with chitosan in patients with ishemic heart disease and hypertension improved clinic, immune status, antropometric levels and lipid spectrum of blood. The research has shown, that the use in the treat-preventive purposes chitosan is rather perspective. 相似文献