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91.
Amplification process in an excimer laser of dense modes is studied. Rate-equations with wavelength dependence are used to reproduce its spectra. Two extreme cases are tried and in spite of the duration of the output pulse relative to the relaxation time, the short pulse limit is proved to describe well the oscillation process of individual mode. 相似文献
92.
采用放大自发辐射模型,利用快速傅里叶变换解傍轴波动方程,考虑衍射,折射和增益饱和,编制了X射线激光在多靶中传播与放大的波动光学和程序XWAVE,给出了X射线激光的空间分布,角分布和空间相干性的结果。计算结果与多靶实验所给出的增益系数和发射角结果相符合。 相似文献
93.
94.
Pi-Tai Chou Chen-Pin Chang John H. Clements Kuo Meng-Shin 《Journal of fluorescence》1995,5(4):369-375
The synthesis and photophysics of 4-formyl-4-N,N-dimethylamino-1,1-biphenyl are reported. The emission spectrum in various solvent polarities demonstrates solvatochromism, indicating that the fluorescence originates from an electronically excited species with a strong charge transfer character. The change in
[
max(absorption) –
max(emission)] varies from 1500 cm–1 inn-heptane to as much as 7500 cm–1 in acetonitrile. In protic solvents, the unusual excitation energy-dependent steady-state emission (red edge effect), resulting from solvent dielectric relaxation, was observed in media with a low viscosity. The large Stokes-shifted and high-yield fluorescence led to the observation of the efficient lasing action. The frequency tunability of the laser output is strongly solvent dependent, generating a new charge transfer laser dye in the blue-green region. 相似文献
95.
LI Tie-sheng Masaya Mitsuishi Tokuji Miyashta 《高等学校化学研究》2006,22(4):543-546
IntroductionDeep-UV lithography is generally recognized asthe most promising lithographic technology, for the pro-duction of high-resolution devices. However, lithogra-phy requires high sensitivity, high resolution, and highresistance. To make this techno… 相似文献
96.
A novel method for performing in-column field-amplified sample stacking (FASS) in chip-based electrophoretic systems is presented. The methodology involves the use of a narrow sample channel (NSC) injector. NSC injectors allow sample plugs to be introduced directly into the separation channel, and subsequent stacking and separation can proceed without any need for leakage control. More importantly, stacking and separation occur in a single step negating the requirement for complex channel geometries and voltage switching to control sample plugs during the stacking procedure. The chip is composed of six paralleled systems. Using the NSC injector design, the number of reservoirs in the multiplexed chip is reduced to N + 2, where N is the number of paralleled systems. This design feature radically reduces the complexity in chip structures and associated chip operation. The approach is applied to the analysis of fluorescently labelled biogenic amines affording detection at concentrations down to 20 pM. 相似文献
97.
A novel, rapid, and continuous online concentration approach based on field-amplified sample injection for the analysis of fangchinoline and tetrandrine was developed in this paper by combination of flow injection-MEKC. The BGE used was a solution composed of 75 mM H3PO4-triethylamine-2.5% v/v polyoxyethylene sorbitan monolaurate-20% v/v methanol buffer (pH* 5.0). The analytes prepared in 50% v/v aqueous ethanol were used as the test analytes. Sample was injected electrokinetically between plugs of water. When the cations reached the boundary between the water plug and BGE, they slowed down and became concentrated. Thereafter, MEKC was initiated for the separation. This results in 6.8-8.9-fold improvement in concentration sensitivity relative to conventional CE methods. The separation could be achieved within 10 min and sample throughput rate can reach up to 50/h. The repeatability (defined as RSD) was 4.8, 4.4% with peak height evaluation and 3.6, 0.94% with peak area evaluation for TET and FAN, respectively. 相似文献
98.
A simple, effective, and continuous online concentration method for the sensitive detection of alkaloids applying CE-flow injection analysis with head-column field-amplified sample stacking was developed. A series of samples was continuously introduced into the capillary by electrokinetic means without interrupting the high voltage. A short water plug was introduced by the EOF at the capillary inlet end prior to sample introduction. Under optimum conditions, 15-fold improvement in concentration sensitivity was achieved, giving an LOD of about 0.67 and 0.73 microg/mL for ephedrine (E) and pseudoephedrine (PE), respectively. The separation could be achieved within 4 min and sample throughput rate could reach up to 7/h. The repeatability (defined as RSD) was 3.62, 1.51% with peak area evaluation and 1.30, 2.58% with peak height evaluation for E and PE, respectively. This method has been successfully applied to the analysis of commercial pharmaceutical preparations containing E and PE, and the recoveries were 92.3-102.4%. 相似文献
99.
Minsheng Li Xiaoyan Chen Yuan Guo Bingyu Zhang Fengxiang Tang Xiaoping Wu 《Electrophoresis》2016,37(23-24):3109-3117
The profiling of the most lethal paralytic shellfish poisoning toxins (PSTs) in freshwater has increased the need to establish an alternative analytical method with high sensitivity and resolution. In this paper, a coupling technique of field‐amplified sample injection (FASI) and CE with end‐column amperometric detection (CE‐AD) was developed to improve the detection sensitivity and separation of PSTs by electrokinetically injecting a water plug of analytes to the capillary filled with a high‐conductivity BGE. Parameters affecting FASI and CE process were carefully adjusted to achieve the highest response and resolution. Separation selectivity for PSTs, especially for the analogues and epimers, was greatly enhanced by using 40 mM Britton–Robinson buffer (pH 9.5) as BGE, which altered the EOF and mobility of the analytes that interacted with polyborate ions. Satisfactory linear relationship between peak current and concentration of toxins were gained over a wide range of 1.95–254 μg/L. The detection limits (S/N = 3) for five PSTs ranged from 0.63 to 3.11 μg/L, which are below the health alert level in drinking water. In comparison with the up‐to‐date reporting chromatographic methods, the FASI‐CE‐AD method was simple, low‐cost, selective, and sensitive enough for direct quantification of PSTs at very low levels, implying a potential for screening and monitoring of PSTs in surface waters. 相似文献
100.
Low thresholds for a nonconventional polymer blend—Amplified spontaneous emission and lasing in F81−x:SYx system
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Haider Butt Kamran ul Hasan Jui‐Fen Chang Ayooye Abigael Olawoyin Richard Henry Friend 《Journal of Polymer Science.Polymer Physics》2016,54(1):15-21
A mixture of two polymer materials, poly (9,9‐dioctylfluorene) (F8), and one of the poly(para‐phenylenevinylene) derivatives, superyellow (SY) have been used to make F81?x:SYx polymer blend system. Under a 3–5 ns pulsed‐laser excitation, this system showed excellent optical properties with low threshold values of ≈14 µJ/cm2 and ≈8 µJ/cm2 for amplified spontaneous emission and optically pumped lasing, respectively. The proposed system was also electroluminescent and an interesting candidate for future research on polymer injection lasers. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 15–21 相似文献