Theoretical simulation and analysis of large size BMP-LSC by 3D Monte Carlo ray tracing model

Luminescent solar concentrators(LSC) can reduce the area of solar cells by collecting light from a large area and concentrating the captured light onto relatively small area photovoltaic(PV) cells, and thereby reducing the cost of PV electricity generation. LSCs with bottom-facing cells(BMP-LSC) can collect both direct light and indirect light, so further improving the efficiency of the PV cells. However, it is hard to analyze the effect of each parameter by experiment because there are too many parameters involved in the BMP-LSC. In this paper, all the physical processes of the light transmission and collection in the BMP-LSC were analyzed. A three-dimensional Monte Carlo ray tracing program was developed to study the transmission of photons in the LSC. A larger-size LSC was simulated, and the effects of dye concentration, the LSC thickness, the cell area, and the cell distance were systematically analyzed.     

A simple procedure for evaluating the heterogeneity parameter and the ratio of molecular sizes of solute and solvent by using HPLC data

Based on the relationship defining the dependence of the capacity ratio upon the composition of the mobile phase, a simple numerical procedure is proposed for evaluating the heterogeneity parameter and the ratio of molecular sizes of solute and solvent. This procedure is examined by using HPLC data for pesticides chromatographed in isooctane/dichloromethane eluent on Lichrosorb at 291 K.     

Formation and migration of zones in overloaded preparative liquid-solid chromatography

Summary An equilibrium sandwich chamber for continuous thinlayer chromatography was used to study overloaded systems of the heptane + methylene chloride-silica type. Mixtures of two or three dyes were used as the model samples. Wide starting zones were formed using a glass distributor (frontal chromatography stage), then the movement of the zones was recorded during continuous elution. The effect of sample concentration and volume on the maximum separation yield was investigated. Band compression effects are illustrated for samples dissolved in solvents having a low eluent strength. Satisfactory analogy was found to separations in preparative column chromatography. Good separation yield was obtained for frontal + elution TLC: depending on the differences in the R_F values of the components, 6–16 mg samples were completely separated on 0.5×100×75 mm layers containing ca. 1 g of silica.Presented at the Eighth International Symposium on Liquid Chromatography, Baden-Baden, 3–7 May 1983.     

Comparative bioanalytical study of3H-deramciclane in dog plasma, using a gas chromatography-nitrogen-selective detection (GC-NPD), a new GC-radiochemical detection (GC-RD) and a liquid scintillation method

Summary A new, highly sensitive and selective gas chromatography method, using radiochemical detection (GC-DR) was developed for the selective determination of³H-labelled deramciclane and its N-desmethyl metabolite in dog plasma. Inter-day accuracy and precision, as well as system suitability of the GC-RD method was investigated during the method validation. The calibration curve was proved to be linear (r=0.9986) in a wide concentration range (13–1000 ngeqv mL⁻¹) The lower limit of quantitation (LLOQ) was 13.7 ngeqv mL⁻¹, and the limit of the detection (LOD) was 1 ngeqv mL⁻¹. Using this new GC-RD method, plasma levels of³H-labelled deramciclane and its metabolite were determined in dogs, after the administration of a single 10 mg kg⁻¹ oral dose. Pharmacokinetic curves and the calculated pharmacokinetic parameters were compared to those obtained using a previously elaborated gas chromatography-nitrogen selective detection method (GC-NPD) and to those obtained by measuring the plasma level of total radioactivity (liquid scintillation counting, LSC). Pharmacokinetic curves and the calculated pharmacokinetic parameters obtained with the two different gas chromatography detection methods (NPD and RD) showed good correlation. Comparison of these results to those acquired by total radioactivity measurement demonstrated that deramciclane was intensively metabolised. Moreover, the biological half-life (t ₁ ^2/β ) of the unknown metabolites proved to be more than a magnitude longer than the half-life of the parent compound or that of N-desmethyl metabolite. Presented at: Balaton Symposium on High-Performance Separation Methods, Siófok, Hungary, September 3–5, 1997.     

Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples

The radiometric methods, alpha (α)-, beta (β)-, gamma (γ)-spectrometry, and mass spectrometric methods, inductively coupled plasma mass spectrometry, accelerator mass spectrometry, thermal ionization mass spectrometry, resonance ionization mass spectrometry, secondary ion mass spectrometry, and glow discharge mass spectrometry are reviewed for the determination of radionuclides. These methods are critically compared for the determination of long-lived radionuclides important for radiation protection, decommissioning of nuclear facilities, repository of nuclear waste, tracer application in the environmental and biological researches, these radionuclides include ³H, ¹⁴C, ³⁶Cl, ⁴¹Ca, ^59,63Ni, ^89,90Sr, ⁹⁹Tc, ¹²⁹I, ^135,137Cs, ²¹⁰Pb, ^226,228Ra, ²³⁷Np, ²⁴¹Am, and isotopes of thorium, uranium and plutonium. The application of on-line methods (flow injection/sequential injection) for separation of radionuclides and automated determination of radionuclides is also discussed.     

Multilayer effects in liquid adsorption chromatography with mixed mobile phases

This paper describes the theory of liquid adsorption chromatography (LSC) with mixed mobile phase, involving formation of multilayer surface phases. An equation describing the dependence of the capacity ratio upon the mobile phase composition is derived and theoretical curves illustrating the same dependence are calculated accordingly by assuming different thicknesses of the surface phase.     

Simultaneous determination of radionuclides separable into natural decay series by use of time-interval analysis

A delayed coincidence method, time-interval analysis (TIA), has been applied to successive – decay events on the millisecond time-scale. Such decay events are part of the ²²⁰Rn²¹⁶Po (T_1/2 145 ms) (Th-series) and ²¹⁹Rn²¹⁵Po (T_1/2 1.78 ms) (Ac-series). By using TIA in addition to measurement of ²²⁶Ra (U-series) from -spectrometry by liquid scintillation counting (LSC), two natural decay series could be identified and separated. The TIA detection efficiency was improved by using the pulse-shape discrimination technique (PSD) to reject -pulses, by solvent extraction of Ra combined with simple chemical separation, and by purging the scintillation solution with dry N₂ gas. The U- and Th-series together with the Ac-series were determined, respectively, from alpha spectra and TIA carried out immediately after Ra-extraction. Using the ²²¹Fr²¹⁷At (T_1/2 32.3 ms) decay process as a tracer, overall yields were estimated from application of TIA to the ²²⁵Ra (Np-decay series) at the time of maximum growth. The present method has proven useful for simultaneous determination of three radioactive decay series in environmental samples.     

Application of chlorine-36 technique in determining the age of modern groundwater in the Al-Zulfi province,Saudi Arabia

The present study aims to estimate the residence time of groundwater based on bomb-produced ³⁶Cl. ³⁶Cl/Cl ratios in the water samples are determined by inductively coupled plasma mass spectrometry and liquid scintillation counting. ³⁶Cl/Cl ratios in the groundwater were estimated to be 1.0–2.0?×?10^?12. Estimates of residence time were obtained by comparing the measured bomb-derived ³⁶Cl concentrations in groundwater with the background reference. Dating based on a ³⁶Cl bomb pulse may be more reliable and sensitive for groundwater recharged before 1975, back as far as the mid-1950s. The above ³⁶Cl background concentration was deduced by determining the background-corrected Dye-3 ice core data from the frozen Arctic data, according to the estimated total ³⁶Cl resources. The residence time of 7.81?×?10⁴ y is obtained from extrapolated groundwater flow velocity. ³⁶Cl concentration in groundwater does not reflect the input of bomb pulse ³⁶Cl, and it belongs to the era before 1950.     

基于量子点的荧光型太阳能聚光器

近年来,量子点在结构可控、光谱调节和光学稳定方面的研究进展,表明基于量子点的聚光器件表现出优于基于传统有机染料分子的光输出性能。量子点聚光器成为目前量子点研究领域的新方向。量子点在宏量制备和绿色制备方面的深入研究,使得量子点的制造成本逐步降低,基于量子点的聚光器具有光电转换效率和成本上的优势。本文综述了量子点聚光器的研究进展,主要包括荧光型聚光器的优点、聚光器对量子点光学性质的要求、器件制备的工艺和器件的性能表征方法。重点阐述了量子点的太阳光吸收能力、荧光量子产率和重吸收等关键因素对聚光器件性能的影响,同时介绍了该领域目前最新的研究方向,展望了廉价太阳能窗户在未来城镇建筑上的潜在应用。     

PbSe量子点在太阳能荧光聚集器中的应用研究

将PbSe量子点成功引入到了太阳能荧光聚集器(LSC)的应用中,利用光子追踪的方法,成功建立了一种基于Monte Carlo模拟方法的模型,通过实验测量,得到PbSe量子点相关数据, 在这些数据基础上,对PbSe量子点LSC的各个参数进行模拟优化,并在优化的条件下,对基于PbSe量子点LSC对太阳能电池单位输出能量造价进行考察,发现通过PbSe量子点LSC的引入,太阳能电池的造价可以降低49.2%,说明PbSe量子点非常适用于LSC体系。