高重频三向侧面泵浦DPL耦合系统设计

激光二极管侧面泵浦容易将大功率二极管阵列(LDA)光耦合到激光晶体中去,但耦合效率有待于进一步的提高.在已建立的二极管单bar侧面泵浦YAG晶体泵浦光场分布数值模型的基础上,进一步分析了三向侧面泵浦激光器晶体内光强的分布,并全面考虑了耦合系统相关的因素,结合实际设计出LD三向侧面泵浦耦合光学系统,最终获得了重复频率1～1 000 Hz可调,波长1.064 μm的TEMoo模的调Q窄脉冲激光输出.激光输出最大单脉冲能量为11.5 mJ,脉冲宽度为8 ns,光-光转换效率为11.7%.实验验证了该耦合系统的合理性与优越性,为高效耦合系统的进一步优化奠定了基础.     

再入飞行器驻点流光辐射特性的理论建模

本文用直接模拟蒙特卡罗法，对再入体驻点区域的流场、光辐射特性进行了研究．针对头部锥体驻点区（包括激波层），建立了流场中的化学反应模型，中性粒子和等离子体的热运动、粒子间碰撞的理论模型，碰撞激发辐射和化学发光辐射的物理模型．给出了样本粒子运动方向和速率、粒子碰撞对的选择等蒙特卡罗法概率模型和计算方法．     

Perylene diimide copolymers with dithienothiophene and dithienopyrrole: Use in n‐channel and ambipolar field‐effect transistors

Solution‐processable polymers consisting of perylene diimide (PDI) acceptor moieties alternating with dithienothiophene (DTT), N‐dodecyl‐dithienopyrrole (DTP), or oligomers of these donor groups have been synthesized. We have, in addition to varying the donor, varied the N,N′ substituents of the PDIs. The thermal, optical, electrochemical, and charge‐transport properties of the polymers have been investigated. The polymers show broad absorption extending from 300 to 1000 nm with optical band gaps as low as 1.2 eV; the band gap decreases with increasing the conjugation length of donor block, or by replacement of DTT by DTP. The electron affinities of the polymers, estimated from electrochemical data, range from ?3.87 to ?4.01 eV and are slightly affected by the specific choice of donor moiety, while the estimated ionization potentials (?5.31 to ?5.92 eV) are more sensitive to the choice of donor. Bottom‐gate top‐contact organic field‐effect transistors based on the polymers generally exhibit n‐channel behavior with electron mobilities as high as 1.7 × 10^–2 cm²/V/s and on/off ratios as high as 10⁶; one PDI‐DTP polymer is an ambipolar transport material with electron mobility of 4 × 10^–4 cm²/V/s and hole mobility of 4 × 10^–5 cm²/V/s in air. There is considerable variation in the charge transport properties of the polymers with the chemical structures. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

New series of AB2‐type hyperbranched polytriazoles derived from the same polymeric intermediate: Different endcapping spacers with adjustable bulk and convenient syntheses via click chemistry under copper(I) catalysis

In this article, according to the concept of “suitable isolation group,” six new AB₂‐type polytriazoles containing azo‐chromophore moieties, derived from the same hyperbranched polymer intermediate, were successfully prepared through click reaction under copper(I) catalysis by modifying the synthetic route, in which different isolation groups in different size were introduced to the periphery of the hyperbranched polymers as end‐capping moieties. With the different end‐capping groups, these hyperbranched polymers, P1 – P6 , exhibited different solubility and processability; also, their nonlinear optical properties were modified accordingly, realizing the adjustment of the properties of hyperbranched polymers through the structural design. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and Characterization of New Schiff Base and Polyoxa-azaCryptands and Their Rare Earth Cryptates with [1 1] Condensation and Reduction Methods

IntroductionWithspecialandnovelstructures,macropolycyclicmoleculespreselltamultitudeofnewproperties'andopenupvastvistasforapplicationsinmanyfields"',suchassupramoleculardevices,luminescentlabels,fluorescentprobesinbiologicalandmedicalapplications,magneticresonanceimagingandcatalyticcleavageofRNA,and.-theyarealsoimportantligands'forrecognizinginorganicandorganiccanons,anionsandneutralmolecules.Becauseofmulti-stepprocessandlowyields',thesynthesisofmacropolycycliccompoundsaresometimesverydifficu…     

光电密码锁的实验研究

介绍了以红外为信号的光电密码锁的工作原理,并对其各个器件的性能进行了分析.该实验有利于学生掌握光电器件的特性及使用方法,掌握光电密码锁的基本知识.     

多星联合鲁棒性调度模型研究

在多星联合调度过程中,存在着很多不确定性因素,其中云层覆盖变化是主要的不确定性来源.本文针对考虑云层覆盖变化的多星联合调度问题,借鉴了连续函数的鲁棒性优化思想,提出了一种基于邻域的鲁棒性指标.在此基础上,建立了多星联合鲁棒性调度模型,给出了观测任务优先级的计算方法.实例研究表明,本文建立的模型能够在保证调度方案性能的基础上,获得鲁棒性强的调度方案.     

Determination of inorganic anions in ethyl acetate by in-line hollow fiber membrane extraction with ion chromatography

In this work,a novel hollow fiber membrane extractor was set up to extract inorganic anions from ethyl acetate using deionized water.Inorganic anions in slightly soluble organic solvents can be determined by the in-line hollow fiber membrane extractor coupled with ion chromatography at first time.Different aspects of the extraction procedure such as magnetic stirring speed, extraction flow rate and extraction time were optimized to achieve high extraction efficiency and good separation results. Satisfact...     

Hyperpolarizabilities of Chelidamic Acid Complexes M_m(C_7H_3O_5N)_n (M=Cu, Ag): Theoretical Analysis

The frequency‐dependent hyperpolarizabilities of chelidamic acid complexes M_m(C₇H₃O₅N)_n (M?Cu, Ag) were investigated under the time dependent density functional theory (TDDFT) combined with the sum‐over‐states method (SOS). The relationship between molecular orbitals and nonlinear optical (NLO) properties has been explored. The results show that the charge transitions of π‐π* and 3d_M‐π* are very important to the second‐order polarizabilities, and the largest component of dynamic β is 3.84×10^?25 cm⁵·esu^?1 at 0.74 eV for Ag₂Cu₂(C₇H₃O₅N)₄. The charge transition between π‐π* is also highly crucial to the third‐order polarizabilities, and the largest component of dynamic γ is ?4.46×10^?29 esu at 0.50 eV for Ag₂Cu₂(C₇H₃O₅N)₄. The central Cu ion, as electron bridge, extends the range of delocalization and leads to an interesting phenomenon of spiroconjugation.