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1.
Measurement of the First Hyperpolarizability of Substituted Ketene N,S-acetals by Hyper-Rayleigh Scattering in Solution 总被引:1,自引:1,他引:0
MeasurementoftheFirstHyperpolarizabilityofSubstitutedKeteneN,S-acetalsbyHyper-RayleighScatteringinSolutionGAOXingyu;CHENJingb... 相似文献
2.
本文利用飞秒时间分辩光克尔效应,对主链为C=N结构的两种共轭聚腈高分子的溶液和薄膜进行研究,所测得的时间分辨光克尔信号均表现为超快响应。 相似文献
3.
近年来,大电流的监测成了人们十分关心的问题,这是由于大电流有强磁、高压、电流大等一系列的直接监测所不能克服的问题。这就需要把高压大电流的强电信号,经过提取后变成能在实验室中直接观测的弱电信号。为此,如何从高压大电流的信号中提取出随实时信号变化而实时变化的小信号就变成了一个关键问题。详细介绍了监测信号提取的光收发电路原理和后续信号处理电路,分析了各部分的作用,给出了必要的分析结果。 相似文献
4.
Dynamic bandwidth allocation for quality-of-service over Ethernet PONs 总被引:24,自引:0,他引:24
Assi C.M. Yinghua Ye Sudhir Dixit Ali M.A. 《Selected Areas in Communications, IEEE Journal on》2003,21(9):1467-1477
Ethernet-based passive optical network (EPON) technology is being considered as a promising solution for next-generation broadband access networks due to the convergence of low-cost Ethernet equipment and low-cost fiber infrastructures. A major feature for this new architecture is the use of a shared transmission media between all users; hence, medium access control arbitration mechanisms are essential for the successful implementation of EPON: i.e., to ensure a contention-free transmission and provide end users with equal access to the shared media. We propose to use the multipoint control protocol defined by the IEEE 802.3ah task force to arbitrate the transmission of different users, and we present different dynamic bandwidth allocation (DBA) algorithms to allocate bandwidths effectively and fairly between end users. These DBA algorithms are also augmented to support differentiated services, a crucial requirement for a converged broadband access network with heterogeneous traffic. We show that queueing delays under strict bandwidth allocation algorithms result in an unexpected behavior for certain traffic classes, and we suggest the use of DBA with appropriate local queue management to alleviate this inappropriate behavior. We conduct detailed simulation experiments to study the performance and validate the effectiveness of the proposed protocols. 相似文献
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The non-isothermal crystallization kinetics of poly(ethylene terephthalate) (PET) modified by poly (ethlene glycol) (PEG) were determined by DSC. The dual linear regression method was used to evaluate the relationship between the reciprocal of t 1/2 ( the half life of crystallization) and the appropriate temperature variable. The parameters such as the activation energy (Ed) for transport, the equilibrium melting temperature (T_m~0),the nucleation parameter (ψ),themaximum crystallization temperature (T_(e, max)), and the kinetic crystallizability (G) for the copolyesters were obtained. The influence of the PEG content in PET chains on the parameters characterizing crystallization kinetics and crystallization thermodynamics was discussed. 相似文献
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本文用自制的单一或复合的微生物传感器作检测器,与高效液相色谱结合,对7种氮基酸,5种有机醇,以及同化糖与醇,维生素等7种混合体系进行分离硷测,取得较好的结果。 相似文献
9.
A sensitive and selective method using liquid chromatography with electrospray ionization mass spectrometric detection was
developed for the quantification of bilobalide and ginkgolides in canine plasma. The analytes were extracted with diethyl
ether-dichloromethane-isopropanol (6:3:1, v/v) after spiking the samples with daidzein (internal standard). The lower limit
of quantification (LLOQ) of the method was 2.5 μg L−1 for ginkgolide B and 10.0 μg L−1 for bilabolide, ginkgolide A and ginkgolide C. The accuracy of the method was within 15% of the actual values over a wide
range of plasma concentrations. The intra-day and inter-day precision was better than 15% (R.S.D.). Finally, the LC-ESI-MS
method was successfully applied to study the pharmacokinetics of ginkgolides and bilabolide after administration of Ginkgo biloba extracts to dogs. 相似文献
10.
A rigorous and practical methodology for evaluating thermal-equilibrium density matrices, finite-temperature time-dependent expectation values, and time-correlation functions is described. The method involves an extension of the matching-pursuit/split-operator-Fourier-transform method to the solution of the Bloch equation via imaginary-time propagation of the density matrix and the evaluation of Heisenberg time-evolution operators through real-time propagation in dynamically adaptive coherent-state representations. 相似文献