绩效度量的一致性、敏感性及准确性关系研究

将环境的波动性和度量噪音看作是影响绩效度量的两类不同的随机误差,在Linear-exponential-normal框架下,建立了以价值绩效度量和补偿绩效度量的线性组合为基础的收益激励模型,并分析了激励强度与绩效度量的一致性、敏感性和准确性之间的关系,以及环境波动性对上述关系的影响.研究发现,在确定性环境条件下,激励强度与绩效度量的"信号噪音比"成正比关系,但绩效度量的一致性的提高并不必然增加该度量指标在激励契约中的权重,而要视敏感性或噪音相对于一致性的变化幅度来定.特别地,在绩效度量的敏感性与一致性之间并不存在权衡取舍关系.研究还发现,波动性与激励强度之间存在负向关系,且波动性的存在降低了绩效度量的一致性和敏感性,但波动性对绩效度量的准确性的影响则呈非单调性变化.     

改性松香键合二氧化硅高效液相色谱固定相的制备及其对三七总皂苷的分离

三七中发挥药效的主要成分为三七皂苷R1、人参皂苷Rg1、人参皂苷Re、人参皂苷Rb1和人参皂苷Rd,用于贫血、冠心病、高血压、脑卒中后遗症等疾病的治疗,但其化学成分多且难分离.将氢化松香丙烯酸羟乙酯(HRHA)通过巯基-烯点击化学反应键合到烷基化硅胶表面,制备出一种新型的改性松香键合二氧化硅高效液相色谱固定相(SiO2...     

弱耦合一维扩展赫伯特模型的基态相图

我们利用玻色化和重整化群分析的方法研究了半满填空且排斥势小于跃迁动能时的一维扩展赫伯特模型的基态相图,发现基态相图是由自旋密度波,电荷密度波和键荷密度波组成.这些结果揭示了扩展赫伯特模型和赫伯特模型基态相图的差异.     

Systeme Binaire AgNO3-LiNO3. Diagramme de phases et proprietes thermodynamiques des mélanges a l’etat liquide

To study the coherence of thermodynamic data of the AgNO₃-LiNO₃ -RbNO₃ ternary system, phase diagram of the binary system AgNO₃ -LiNO₃ has been obtained between 303 and 550 K by direct and differential thermal analysis technique. This system is characterized by an eutectic point (25% mol. LiNO₃ , 445±1 K) and a plateau due to the solid-solid transition in AgNO₃ at 434±1 K. In the solid state the solubility of each component in the other seems to be nil or negligible (no more than a few percents). Using other thermodynamic data, the excess properties of the binary liquid (AgNO₃ - LiNO₃ ) were calculated at 623 K. This revised version was published online in August 2006 with corrections to the Cover Date.     

Large-aperture double-focus laser collimator for PAT performance testing of inter-satellite laser communication terminal

A laser collimator is necessary for testing and verification of the pointing, acquisition and tracking (PAT) performance of inter-satellite laser communication terminals on the ground. The laser collimator must have a large clear aperture to fit the PAT performance testing system. The PAT subsystem has a large field of view for the acquisition and a high angular accuracy for the fine tracking. To resolve the conflict between large field of view and fine angular resolution, a large-aperture double-focus laser collimator is proposed and its optical design and mechanical structure are described. The collimator mainly consists of a primary lens, a reflector, a beam-splitting plate, a secondary lens, two compensating lenses, two imaging sensors and a laser. The primary lens directly forms the long focal length arm of the collimator. The combination of the primary lens and the secondary lens form the short focal length arm of the collimator. The collimator has an angular resolution <0.75 μrad and a 10 mrad field of view. For the collimator, the incident beam is focused on the two imaging sensors by its two arms, and the beam emitted from the laser is collimated and transmitted. The collimator is combined with an optical scanner and a fine beam deflector to test and verify the PAT performance of the inter-satellite laser communication terminal in a full physical manner.     

Impedance of faradeic process with partial charge transfer

The electrochemical impedance of charge-transfer reaction involving the stages of adsorption and desorption of intermediate partially charged substance is analyzed theoretically in the frequency-potential plane in order to study the possibility for measuring the partial charge transfer. The simplest case of adsorption two-electron transfer, namely, the Langmuir adsorption with liner dependence of reaction rate on the coverage, is considered. It is assumed that the partial charge transfer is independent of the electrode potential.     

Quantitative analysis of 3‐OHB[a]P and (+)‐anti‐BPDE as biomarkers of B[a]P exposure in rats

The aim of this study was to develop an analytical method for the determination the levels of metabolites of benzo[a]pyrene (B[a]P), 3‐hydroxybenzo(a)pyrene (3‐OHB[a]P) and (+)‐anti‐benzo(a)pyrene diol‐epoxide [(+)‐anti‐BPDE, combined with DNA to form adducts], in rat blood and tissues exposed to B[a]P exposure by high‐performance liquid chromatography with fluorescence detection (HPLC/FD), and to investigate the usefulness of 3‐OHB[a]P and (+)‐anti‐BPDE as markers of intragastrical exposure to B[a]P in rats. The levels of 3‐OH‐B[a]P and B[a]P‐tetrol I‐1 released after acid hydrolysis of (+)‐anti‐BPDE in the samples were measured by HPLC/FD. The calibration curves were linear (r² > 0.9904), and the lower limit of quantification ranged from 0.34 to 0.45 ng/mL for 3‐OHB[a]P and from 0.43 to 0.58 ng/mL for (+)‐anti‐BPDE. The intra‐ and inter‐day stability assay data suggested that the method is accurate and precise. The recoveries of 3‐OHB[a]P and (+)‐anti‐BPDE were in the ranges of 73.6 ± 5.0 to 116.5 ± 6.3% and 73.3 ± 8.5 to 141.2 ± 13.8%, respectively. A positive correlation was found between the concentration of intragastrical B[a]P and the concentrations of 3‐OH‐B[a]P and (+)‐anti‐BPDE in the blood and in most of the tissues studied, except for the brain and kidney, which showed no correlation between B[a]P and 3‐OHB[a]P and between B[a]P and (+)‐anti‐BPDE, respectively. A sensitive, reliable and rapid HPLC/FD was developed and validated for analysis of 3‐OHB[a]P and (+)‐anti‐BPDE in rat blood and tissues. There was a positive correlation between the concentration of 3‐OHB[a]P or (+)‐anti‐BPDE in the blood and the concentration of 3‐OHB[a]P or (+)‐anti‐BPDE in the most other tissues examined. The concentration of 3‐OHB[a]P or (+)‐anti‐BPDE in the blood could be used as an indicator of the concentration of 3‐OHB[a]P or (+)‐anti‐BPDE in the other tissues in response to B[a]P exposure. These results demonstrate that 3‐OHB[a]P and (+)‐anti‐BPDE are potential biomarkers of B[a]P exposure, which would also be useful to assess the carcinogenic risks from B[a]P exposure. Copyright © 2015 John Wiley & Sons, Ltd.     

Tuning the frontier molecular orbital energy levels of n‐type conjugated copolymers by using angular‐shaped naphthalene tetracarboxylic diimides,and their use in all‐polymer solar cells with high open‐circuit voltages

An angular‐shaped naphthalene tetracarboxylic diimide (NDI) was designed and synthesized as a new building block for n‐type conjugated polymers to tune their energy levels. Three n‐type copolymers incorporating this angular‐shaped NDI as the acceptor moiety were obtained by Stille coupling reactions and had number average molecular weights of 18.7–73.0 kDa. All‐polymer bulk‐heterojunction solar cells made from blends of these polymers with poly(3‐hexylthiophene) gave a power conversion efficiency up to 0.32% and exhibited an open‐circuit voltage (V_oc) up to 0.94 V due to their relative high‐lying lowest unoccupied molecular orbital energy levels. The high V_oc of 0.94 V is higher than that of solar cells based on linear‐shaped NDI‐containing polymers (<0.6 V). The results indicate that the angular‐shaped NDI is a promising building block for constructing nonfullerene polymer acceptors for solar cells with high open‐circuit voltages. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Analysis of photo-chemical degradation behaviour of polyethylene mulching film with pro-oxidants

It is generally accepted that polyolefins are bioinert. The last years, a new class of photodegradable polyethylene films with pro-oxidants has been developed, exhibiting optimised operational properties in terms of controlled UV and/or thermal ageing leading to an abrupt, predefined to some extent, rapid fragmentation into very small fragments. These photodegradable or fragmentable polyethylene films are promoted in the market for various commercial applications. In some cases, these materials are presented as, or are claimed to be, biodegradable materials. Such materials are already used in agriculture in the form of photodegradable mulching films which become fragmented into small remains after the end of their useful lifetime and are incorporated into the soil. However, it has not been verified yet beyond any doubt, that these remains do in fact biodegrade in natural soil, under what conditions, at which rate and what are their effects in agricultural production, the soil and the environment. An experimental investigation has been carried out focusing on the combined effects of critical factors on the controlled (predefined) photo-chemical degradation of photodegradable mulching LLDPE films with pro-oxidants and the behaviour of their remains in the soil. The analysis of the photo-chemical degradation behaviour presented in this paper was carried out through parallel experiments performed under real field and controlled laboratory conditions. The main factors investigated include materials, exposure time, temperature and UV radiation.     

Rapid and Simple Method to Determine Tamoxifen and Its Major Metabolites in Human Liver Microsomes by High Performance Liquid Chromatography with Fluorescence Detection

Abstract

Sensitive and reproducible analyses were developed for assaying tamoxifen, desmethyltamoxifen, didesmethyltamoxifen and hydroxytamoxifen in human liver microsomes by high performance liquid chromatography (H.P.L.C.) following protein precipitation. Detection was by fluorimetry of phenanthrene derivatives formed by on-stream U.V. irradiation with a photochemical reactor enhanced detection (P.H.R.E.D.) for post-column irradiation of the H.P.L.C. stream. The method is highly sensitive (1 ng/ml). A C8,5 μm column (4.6 x 150 mm) was used, with a mobile phase of acetonitrile / 100 mM ammonium acetate (1:1) pH 5. Precipitation of the microsomal protein was carried out by adding methanol and concentrated chloric acid to the reaction mixture, and extraction efficiencies were approximately 100 % for tamoxifen and its metabolites. The assay has been optimised for the identification and quantitation of the 4-hydroxylated metabolite, as well as the two metabolites formed by N-oxidative demethylation of the side chain. The latter catalytic activity involves cytochrome P450 3A enzymes.