热回收在全新风除湿机中的节能研究

分析了GB/T20109-2006所述全新风除湿机节能的5个方面:1)冷凝热回收.2)室内回风热回收.3)冷凝水冷回收.4)处理后新风冷回收.5)新风热回收.通过对典型案例做深入探讨发现:采用板翅式热回收器或热管换热器对新风处理后新风进行冷回收预冷新风,能够降低制冷系统冷负荷20％～30％,显著提高全新风除湿机的单位输入功率除湿量.     

Inverse QR iterative method for subspace tracking

The Bi-LS method based on QR decomposition provides a convenient framework for developing efficient subspace tracking algorithms. To overcome the shortcoming of the backsubstitution step and improve the parallel architecture of the Bi-LS algorithms, a Bi-LS subspace tracking algorithm based on Inverse QR (IQR) decomposition is developed. The proposed IQR iterative algorithm for subspace tracking is well suited for the parallel implementation in the systolic array. Simulation results are presented to illustrate the effectiveness of the proposed IQR subspace tracking algorithm.     

双侧电传动履带车辆模糊前馈-反馈转向控制

针对双侧电传动履带车辆转向控制存在目标跟踪慢和抗干扰性能差等问题,通过车辆动力学分析和驾驶员操控信号解析,在直接转矩控制的基础上设计了一种模糊前馈-反馈转向控制算法。该算法将方向盘转角及变化率作为模糊控制输入,对两侧电机目标转矩进行前馈补偿;采用转向半径的偏差及变化率作为模糊控制输入,对目标转矩差进行反馈修正。通过实时仿真系统dSPACE平台构建车辆的硬件在环实时仿真平台,对控制策略的实时性和可行性进行了验证。结果表明,模糊前馈-反馈控制在车辆不同速度和不同转向半径工况下均能有效缩短转向动态响应时间,同时转向轨迹的抗扰性能得到了提高,实现了车辆快速稳定转向。     

一种提高脉冲电流测量准确度的方法

对脉冲电流的测量,现用设备由数字示波器和电流探头组成,此测量装置的误差限为±1%,对误差限有较高要求的脉冲电流测量,该测量装置存在局限性。本文在上述测量设备的基础上,分析并找出常用方法产生误差的主要来源;为减小误差分量,提出了一种提高脉冲电流测量准确度的方法,即直流电流替代法;并详细阐述了直流电流替代法的工作原理和方法,对改进方法和常用方法进行不确定度分析比较。实验结果表明,改进方法可操作性强,能明显提高电流测量的准确度。     

High-performance inverted polymer solar cells with lead monoxide-modified indium tin oxides as the cathode

The photovoltaic stability of polymer solar cells (PSCs) can be greatly improved by adopting an inverted device structure. This paper reports high-performance inverted PSCs with lead monoxide (PbO)-modified indium tin oxide (ITO) as the cathodes. A thin PbO layer can effectively lower the work function of ITO from 4.5 to 3.8 eV. The optimal inverted PSCs with poly(3-hexylthiophene) (P3HT) as the donor and [6,6]-phenyl-C₆₁-butyric acid methyl ester (PCBM) as the acceptor exhibited high photovoltaic performance: open-circuit voltage of 0.59 V, short-circuit current density of 10.8 mA cm⁻², fill factor of 0.632, and power conversion efficiency of 4.00% under simulated AM1.5G illumination (100 mW cm⁻²). The photovoltaic efficiency is significantly higher than that of the control inverted PSCs with unmodified ITO as the cathode. It is even better than that of the control PSCs with normal architecture, which have an optimal efficiency of 3.5%. The lowering in the work function by the PbO modification is attributed to the charge transfer between PbO and ITO, as evidenced by the X-ray photoelectron spectra.     

High‐Conductivity Poly(3,4‐ethylenedioxythiophene):Poly(styrene sulfonate) Film and Its Application in Polymer Optoelectronic Devices

The conductivity of a poly(3,4‐ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) film can be enhanced by more than two orders of magnitude by adding a compound with two or more polar groups, such as ethylene glycol, meso‐erythritol (1,2,3,4‐tetrahydroxybutane), or 2‐nitroenthanol, to an aqueous solution of PEDOT:PSS. The mechanism for this conductivity enhancement is studied, and a new mechanism proposed. Raman spectroscopy indicates an effect of the liquid additive on the chemical structure of the PEDOT chains, which suggests a conformational change of PEDOT chains in the film. Both coil and linear conformations or an expanded‐coil conformation of the PEDOT chains may be present in the untreated PEDOT:PSS film, and the linear or expanded‐coil conformations may become dominant in the treated PEDOT:PSS film. This conformational change results in the enhancement of charge‐carrier mobility in the film and leads to an enhanced conductivity. The high‐conductivity PEDOT:PSS film is ideal as an electrode for polymer optoelectronic devices. Polymer light‐emitting diodes and photovoltaic cells fabricated using such high‐conductivity PEDOT:PSS films as the anode exhibit a high performance, close to that obtained using indium tin oxide as the anode.     

Hole transfer from PbS nanocrystal quantum dots to polymers and efficient hybrid solar cells utilizing infrared photons

Polymer/inorganic-nanocrystals bulk heterojunction solar cells, where inorganic semiconductor nanocrystals such as CdSe, CdS, CdTe, ZnO, TiO₂, and silicon, replace the fullerene molecules as the electron acceptors, typically exhibit a power conversion efficiency (PCE) below 3% even after tremendous engineering efforts to optimize the nanocrystal size, shape, and nanoscale morphology. One promising feature of polymer hybrid solar cells is the ability to sensitize conjugated polymers, which on their own absorb only in the visible part of solar spectrum, into the infrared spectral range using infrared-active lead salt nanocrystal quantum dots (NQDs). Here we observed for the first time hole transfer from PbS NQDs to polymers as evidenced by the quenching of the PbS photoluminescence (PL), a sign of the presence of charge separating type II heterojunction. The type II band-offset at the NQD/polymer heterojunction enables efficient hole extraction from NQDs and leads to a record PCE of 3.80%, realized in a planar junction configuration under simulated air mass 1.5 global (AM 1.5G) irradiation of 100 mW/cm². The photocurrent has an extended spectral range spanning from the ultraviolet (UV) to the infrared (IR). Contributions from the polymer and PbS to the photocurrent were identified. Infrared photons (>700 nm) contribute about 30% of the photocurrent and yield a high external quantum efficiency (EQE) of 20% at 1050 nm.     

干线传输线路一体化运维管理系统设计与实现

针对目前线路资源、维护任务和网络质量无法统一管理与集中监控的现状,在研究资源模型、任务流程和工作场景的基础上,提出了一种基于 GIS(地理信息系统)平台和 GPS(全球定位系统)智能终端的整体运维管理方案,并进行了管理流程、信息交互、数据验证、用户界面功能的设计与系统实现。实际应用结果表明,该系统显著提高了干线传输线路运维管理的效率。     

OFDM系统的功率和比特分配算法

OFDM(正交频分复用)是高速无线数据通信系统最有力的候选技术之一。在OFDM系统中,能够根据各个信道的衰减对各载波的发送功率和传输的比特数进行动态分配,从而使系统性能达到最佳。首先介绍了功率和比特分配的最优算法、贪婪算法,并针对贪婪算法迭代次数多的不足,提出了一种改进的贪婪算法。该算法通过修改迭代过程的初始条件,大大简化了贪婪算法的计算复杂度。仿真结果表明,改进的贪婪算法能够在保持发送比特总数不变的同时有效减少迭代的次数。     

液晶光阀的双稳态特性研究

测量了TB3639型液晶光阀在电压驱动下的光谱特性及其光学双稳态特性,并讨论其产生光学双稳态特性的非线性效应物理机制,分析了液晶光阀的光学双稳态特性不明显的原因.分析结果表明,扭曲角对液晶光阀的光学双稳态特性影响较大,由于TN型液晶光阀的扭曲角只有90°,导致其双稳态特性不是很明显,TB3639型液晶光阀在某一电压范围内存在光学双稳态特性.