不同投资决策的最优化模型

本文对最优投资决策问题进行了讨论,针对不同的投资决策,分别给出了最优化数学模型,为投资部门科学使用资金、避免盲目投资提供了量化参考。     

基于导频的OFDM系统信道估计

本文介绍了基于导频的OFDM系统信道估计的基本方法,并给出在不同估计准则、不同导频图案下,信道估计性能的对比分析。采用广义平非相关散射下的多径时变瑞利信道模型,对各个算法进行仿真,得出不同算下信道估计的均方误差曲线。仿真结果表明：在快变信道中,梳状导频较块导频有更好的性能;基于MMSE准则的信道估计比基于LS准则的估计有更的性能,但前者复杂度较高。     

碱性介质中茜素黄R与牛血清蛋白相互作用研究

在碱性条件下,采用紫外—可见分光光度法研究了茜素黄R(Alizarin Yellow R)与牛血清白蛋白(BSA)的结合反应。研究表明,AYR—BSA二元配合物的最大吸收波长为386 nm,比AYR紫移约108 nm;建立了碱性条件下以AYR测定蛋白质的光谱分析法,对样品分析表明,回收率为96.4%~106.6%,相对标准偏差为0.28%~1.13%;采用双波长法、平衡透析法和单波长法对AYR与BSA的相互作用的研究结果基本一致,在386 nm处,AYR—BSA配合物的结合比为nAYR:nBSA=5 1,摩尔吸光系数ε=9.12×103L.mol-1.cm-1,相互作用的条件平衡常数K=8.13×105。     

Escape of photo-detached electron from an annular nanomicrocavity

The escaped probability density of the photo-detached electron in an annular nanomicrocavity shows strong oscillations as a function of the length of the escape orbits. We present a semiclassical theory that describes theses oscillations in terms of bundles of escape orbits. Due to the interference effects of the electron waves travelling along different escaped orbits, oscillatory structures appear in the escaped probability density. In addition, the calculation results suggest that the escaped probability density of the photo-detached electron is not only related to the inner radius of the annular microcavity, but also related to the laser polarization. In order to show the correspondence between the escaped probability density and the detached electron’s escaped orbits clearly, we calculate the Fourier transformed semiclassical wave function and find that the peak positions agree well with the length of the detached electron’s orbits. We hope that our results will be useful in understanding the escape and propagation process of particles through semiconductor microjunctions or ballistic microstructure.     

Synthesis of two dihydropyrroloindoledione‐based copolymers for organic electronics

Two novel dihydropyrroloindoledione (DPID)‐based copolymers have been synthesized in a two directional approach and characterized (gel permeation chromatography (GPC), ultraviolet‐visible (UV–vis), cyclic voltammetry, and computational models). These planar, broad absorption copolymers show promise for use in organic electronics, with deep energy levels and low bandgaps. The two‐directional Knoevenagel condensation used demonstrates the versatility of DPID as a useful yet underexploited conjugated unit. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

水热法制备p-CoFe_2O_4/n-CdS及其光催化制氢性能

水热法制备了系列p-n复合半导体p-CoFe_2O_4/n-CdS。采用X射线衍射(XRD)、冷场发射扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)、透射电镜(TEM)和电化学工作站等对制得的光催化剂进行了结构和性能表征。研究了p-CoFe_2O_4/n-CdS复合光催化剂的可见光催化制氢性能及光腐蚀性能,并对光催化活性的提高、反应条件的影响及光腐蚀行为的抑制机理进行了分析。结果表明:由于CoFe_2O_4和CdS两种窄带隙半导体复合增加了光吸收率;CdS独特的树形结构以及CoFe_2O_4和CdS二者复合所产生的能带交迭和内建电场的三重作用,促进了电子从CoFe_2O_4向CdS的迁移,减少电子-空穴对复合的概率,增强了光催化活性。光生电子-空穴对的分离效率以及光催化剂表面吸附性能都对产氢速率有重要影响。CH_3OH水溶液的pH对光催化剂中光生电子-空穴对的分离效率以及光催化剂表面吸附性能都有影响。牺牲剂CH_3OH的加入以及CoFe_2O_4和CdS二者复合所产生的能带交迭和内建电场的作用都对CdS的光腐蚀起了抑制作用,后者的抑制效果更好。     

Effect of aluminum co-doping on the formation of Yb2+ in Ytterbium-doped high silica glass

Yb3+ singly doped and Yb3+/Al3+ co-doped high silica glass samples are prepared,and their luminescent properties are investigated.Al3+ is considered as a beneficial activator for Yb3+-doped glass.However,the experimental result shows that the addition of Al3+ results in the transformation from Yb3+ to Yb2+ and the improvement in the photon luminescence of Yb2+.These characteristics indicate the role of Al3+ in Yb3+-doped glass.     

Pyrenylamine‐functionalized aromatic polyamides as efficient blue‐emitters and multicolored electrochromic materials

A series of novel aromatic polyamides with pyrenylamine in the backbone were prepared from a newly synthesized dicarboxylic acid monomer, N,N‐di(4‐carboxyphenyl)‐1‐aminopyrene, and various aromatic diamines via the phosphorylation polyamidation technique. These polyamides were readily soluble in many organic solvents and could be solution‐cast into tough and amorphous films. They had useful levels of thermal stability with glass‐transition temperatures in the range of 276–342 °C and 10% weight loss temperatures in excess of 500 °C. The dilute N‐methyl‐2‐pyrrolidone (NMP) solutions of these polymers exhibited fluorescence maxima around 455–540 nm with quantum yields up to 56.9%. The polyamides also showed remarkable solvatochromism of the emission spectra. Their films showed reversible electrochemical oxidation and reduction accompanied by strong color changes from colorless neutral state to purple oxidized state and to yellow reduced state. The polyamide 4g containing the pyrenylamine units in both diacid and diamine sides exhibited easily accessible p‐ and n‐doped states, together with multicolored electrochromic behaviors. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

A convergence of photo‐bergman cyclization and intramolecular chain collapse towards polymeric nanoparticles

Employing enediynes as crosslinking precursors, a novel yet efficient strategy, namely photo‐triggered Bergman cyclization, was integrated with intramolecular chain collapse to yield polymeric nanoparticles with the size regime below 20 nm. Enediyne motif was designed delicately to possess a high photo‐reactivity, with the double bond locked in a methyl benzoate ring while triple bonds substituted with phenyls. Single electron transfer‐living radical polymerization was conducted to provide linear acrylate copolymers with controlled molecular weights and narrow polydispersities. Poly(butylarylate‐co‐ 5 ) went through UV‐irradiation with a concurrent Bergman cyclization, resulting in well‐defined ultrafine polymeric nanoparticles. Results from NMR, Raman scattering, photoluminescence and UV‐vis spectra corroborated the presence of conjugative structures in the polymeric nanoparticles, indicating the occurrence of photo‐induced Bergman cyclization. A series of other acrylate‐based nanoparticles were investigated to confirm the applicability of such a unique strategy in thermal sensitive but UV‐stable polymeric structures, making photo‐Bergman cyclization a promising tool towards polymeric nanoparticles. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011