对稳态NUT- Kerr-Newman黑洞的量子隧穿特征的研究

运用Parikh的量子隧穿模型, 研究了NUT- Kerr- Newman黑洞的量子隧穿辐射特征. 研究结果表明, 当考虑能量守恒与角动量守恒时, 稳态NUT- Kerr- Newman黑洞的真实谱不再是纯热谱, 视界处粒子的隧穿率与Bekenstein-Hawking熵有关, 且满足量子力学中的幺正性原理.     

A survey of data envelopment analysis in energy and environmental studies

Data envelopment analysis has gained great popularity in energy and environmental (E&E) modeling in recent years. In this paper, we present a literature survey on the application of data envelopment analysis (DEA) to E&E studies. We begin with an introduction to the most widely used DEA techniques, which is followed by a classification of 100 publications in this field. The main features observed are summarized. Issues related to the selection of DEA models in E&E studies are discussed.     

Implications of energy conditions on standard static space–times

In the framework of standard static space–times, we state a family of sufficient or necessary conditions for a set of physically reasonable energy and convergence conditions in relativity and related theories. We concentrate our study on questions about the sub-harmonicity of the warping function, the scalar curvature map, conformal hyperbolicity, conjugate points and the time-like diameter of this class of space–times.     

Trace elements in human cancerous and healthy tissues: A comparative study by EDXRF,TXRF, synchrotron radiation and PIXE

It is known that trace elements play an important role in a number of biological processes. These include the activation or inhibition of enzymatic reactions, competition between elements and metal proteins for binding positions and modifications in the permeability of cellular membranes. These elements may also influence carcinogenic processes, thus the knowledge of trace element concentrations in healthy and neoplastic tissues might help in diagnostic and in the etiology and development of cancer.     

Factorial design for Fe, Cu, Zn, Se and Pb preconcentration optimization with APDC and analysis with a portable X-ray fluorescence system

Preconcentration of heavy metals in water with ammonium pyrrolydine dithiocarbamate (APDC) is a common practice in analytical chemistry. A literature review on this topic showed that several authors use this precipitation agent, but in different preconcentration conditions, conducting to divergent results. The objective of this work is to use factorial design to optimize the factors involved in the preconcentration process of heavy metals using APDC. Five factors were studied: sample volume, solution pH, APDC concentration, APDC volume and stirring time. The assays were performed by energy dispersive X-ray fluorescence (EDXRF). The values for detection limits within 95% confidence level, in μg L⁻¹, were: Fe (6.0 ± 0.1), Cu (4.0 ± 0.1), Zn (2.0 ± 0.1), Se (4.0 ± 0.1) and Pb (5.0 ± 0.1). The value for quantification limit for the five elements was 20 μg L⁻¹, with 3% deviation. Multi-element standard solutions were prepared. Precipitation procedure was applied in the spiked solutions and the samples were filtered in cellulose ester membrane for quantification measurements. The optimum values obtained were 300 mL of sample solution, pH 4, 1 mL of 2% APDC and 10 min of stirring time. The concentration results obtained for the validation measurements were satisfactory for in situ survey employing a portable instrument.     

Bright White Organic Light-Emitting Diode Mixed Blue and Green Emission

Double-layer and triple-layer organic light-emitting diodes (OLEDs) were fabricated using a novel star-shaped hexafluorenylbenzene organic material, 1,2,3,4,5,6-hexakis(9,9-diethyl-9H-fluoren-2-yl)benzene (HKEthFLYPh) as an energy transfer layer, N, N′-bis-(1-naphthyl)-N, N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) as a hole-transport layer (HTL) and blue emissive layer (EML), and tris(8-hydroxyquinoline)aluminum (Alq₃) as an electron-transport layer (ETL) and green light-emitting layer. Bright white light was obtained with a triple-layer device structure of indium-tin-oxide (ITO)/NPB (40 nm)/HKEthFLYPh (10 nm)/Alq₃ (50 nm)/Mg:Ag (200 nm). A maximum luminance of 8523 cd·m⁻² at 15 V and a power efficiency of 1.0 lm·W⁻¹ at 5.5 V were achieved. The Commissions Internationale de L′Eclairage (CIE) coordinates of the device were (0.29, 0.34) at 9 V, which located in white light region. With increasing film thickness of HKEthFLYPh, light emission intensity from NPB increased compared to that of Alq₃.     

A Bodipy-bearing pillar[5]arene for mimicking photosynthesis: Multi-fluorophoric light harvesting system

Herein, we submitted to the original synthesis, characterization, energy transfer mechanism of the Bodipy-bearing pillar[5]arene Bodipy and its reactants by employing of infrared, ¹H, ¹¹B, ¹³C, ¹⁹F-NMRs, UV–vis, fluorescence spectroscopy, melting point apparatus, CHN elemental analysis and mass spectroscopy. Preliminary UV–vis, fluorescence and excitation measurements were carried out in CH₂Cl₂ and the results revealed an effective fluorescence resonance energy transfer (FRET) system based on the interaction of pillar[5]arene and Bodipy derivative. ε_max of target molecule reached to a maximum value and it was found as 955 000?M^?1?cm^?1. This fluorescent macromolecule worked well for mimicking a light harvesting system with an energy transfer efficiency up to 92%.     

聚合物掺杂的高亮度磷光有机电致发光器件

采用新型贵金属铱的配合物(pbi)2Ir(acac)作为客体磷光发光材料, 分别以4%和5%(w)的浓度掺杂于聚合物主体材料poly(N-vinylcarbazole) (PVK)中, 利用旋涂工艺制备了结构为indium-tin oxide (ITO)/PVK:(pbi)2Ir(acac)/2,9-二甲基-4,7-二苯基-1,10-菲咯啉(BCP)/Mg:Ag的有机电致发光器件, 对磷光材料(pbi)2Ir(acac)的紫外-可见吸收光谱﹑光致发光光谱以及聚合物掺杂的磷光器件的电致发光特性进行了研究. 结果表明, 两种掺杂浓度的器件均具有8 V左右的启亮电压, 器件在启亮后的最大流明效率分别为1.53和1.31 lm·W-1, 最大亮度分别为11210和9174 cd·m-2; 同时, 器件的电致发光光谱与色坐标均不随偏置电压和客体掺杂浓度的变化而改变, 具有稳定的色纯度. 分析了主体材料PVK到磷光客体(pbi)2Ir(acac)的能量转移机制, 并探讨了随着器件电流密度和客体掺杂浓度的逐渐增加, 器件流明效率的变化趋势.     

补偿效应：一条化学/化工动力学基本定律的探讨

补偿效应揭示了Arrhenius方程中反应速率常数k的指数项(-E/RgT)与指前因子(k0)项存在着相互补偿关系。不仅存在于催化与非催化,均相与非均相的反应体系及需要克服能垒的物理过程,而且也存在于生命与非生命、能源、环境与材料等许多领域。本文对补偿效应的定位、理论解释及适用范围进行了探讨,指出其在化学/化工动力学中占有重要位置,不仅是一条定律,而且是与质量作用定律、Arrhenius定律并列的又一条基本定律。本文从统计学角度对补偿效应进行了概率分析,试图对其给出更为广义的理论解释,并指出,均相反应体系和非均相反应体系本质上都是不均匀的。中间络合物生成具有耗散结构特征,在近平衡(准平衡)线性区进行,无序度减小伴随着能量及无序度的同向变化,这是补偿效应存在的根本原因。从而提出了反应速率常数中能量分布、无序度分布的概率因子。其对补偿效应的概率解释与能量指数分布说/焓熵补偿关系说是统一的而非对立的。进而还讨论了自然指数律/自然补偿律,指出补偿效应是自然界存在/运动所遵循的自然律在化学反应领域的具体体现。