室内气态污染物净化技术研究综述及量化对比分析

室内气态污染物的净化是我国居民越来越关注的一个热点问题。近年来气态污染物净化技术的相关研究层出不穷。但多数报道仅关注于某项净化技术,很少横向对比各技术的净化效率。综述了通风换气、吸收和氧化分解三类气态污染物净化技术的原理,量化对比了其中8项技术的净化效率和能耗,分析讨论了各技术优缺点。植物吸收技术、光催化氧化技术、臭氧氧化技术、二氧化氯氧化技术、低温等离子体氧化技术的净化效率相对低于活性炭吸附技术和通风换气类净化技术。一般,多种净化技术复合后的效率优于单一的净化技术。对于光催化氧化、臭氧氧化、二氧化氯氧化、低温等离子体氧化等技术,通过技术的优化或复合,大幅度提高其净化效率后才可能具有商业化应用前景。     

UHF波段六位数字移相器的研究与实现

对应用于相控阵雷达中的六位数字移相器的工作原理进行了深入的研究、并详细地介绍了它的设计方法和测试结果.主要叙述了采用高低通滤波器移相原理实现UHF波段的六位数字移相器,利用ADS软件设计仿真,实现了频带内高移相精度、低插入损耗和低VSWR等较好性能,最后通过矢量网络分析仪HP8753D对实物进行调试和检测.进而验证了设计方案.     

碘代物杂质对TFT液晶性能的影响

为了研究碘代物杂质对TFT液晶性能的影响,设计了不同劣化条件下TFT液晶的保存实验,进行了碘代物掺杂的浓度梯度实验,测试了混晶VHR随碘代物浓度变化的趋势。实验结果表明:在UV照射和加电的劣化条件下,液晶中的碘代物杂质会发生分解,明显降低TFT液晶的VHR参数。液晶中碘代物杂质含量越高,TFT液晶在劣化条件下的稳定性就越差。在本实验条件下,2×10-5浓度的碘代物,已经对液晶可靠性产生明显不良影响。     

Computational design of ratiometric two-photon fluorescent Zn2+ probes based on quinoline and di-2-picolylamine moieties

To improve two-photon absorption (TPA) response of a newly synthesized probe, a series of ratiometric two-photon fluorescent Zn²⁺ sensors based on quinoline and DPA moieties have been designed. The one-photon absorption, TPA, and emission properties of the experimental and designed probes before and after coordination with Zn²⁺ are investigated employing the density functional theory in combination with response functions. The design consists of two levels. In the first level of design, five probes are constructed through using several electron acceptors or donors to increase accepting or donating ability of the fluorophores. It shows that all the designed probes have stronger TPA intensities at longer wavelengths with respect to the experimental probe because of the increased intra-molecular charge transfer. Moreover, it is found that the probe 4 built by adding an acyl unit has the largest TPA cross section among the designed structures due to the form of longer conjugated length and more linear backbone. One dimethylamino terminal attached along the skeleton can improve TPA intensity more efficiently than two side amino groups. Therefore, in the second level of design, a new probe 7 is formed by both an acyl unit and a dimethylamino terminal. It exhibits that the TPA cross sections of probe 7 and its zinc complex increase dramatically. Furthermore, the fluorescence quantum yields of the designed probes 4 and 7 are calculated in a new way, which makes use of the relation between the computed difference of dipole moment and the measured fluorescence quantum yield. The result shows that our design also improves the fluorescence quantum yield considerably. All in all, the designed probes 4 and 7 not only possess enhanced TPA intensities but also have large differences of emission wavelength upon Zn²⁺ coordination and strong fluorescence intensity, which demonstrates that they are potential ratiometric two-photon fluorescent probes.     

一种基于DFP-BFGS算法与微扰法的波束赋形方法

本文利用微扰迭代法对DFP-BFGS无约束最优化方法进行改进,解决了不能全局优化的缺点。首先对构造的目标函数进行阵列各单元激励幅度和相位同时进行全局优化,然后对得到的阵列激励幅度分布数据进行部分调整,使其更加均匀以便于馈电网络的设计,最后固定激励幅度分布,对相位分布进行优化。在实现对方向图主瓣波束赋形的同时,得到了较为均匀的激励幅度分布。该优化方法具有应用灵活和结果可调控的优点,是一种实现阵列天线波束赋形的实用方法。