高动态范围（HDR）激光显示一方面可以显示接近人眼动态范围的高对比度场景，另一方面可以最大化显示色域，是下一代显示技术的重要发展方向。为了实现高亮度、高效率、低成本的HDR激光显示，提出了一种基于区域调光的HDR激光显示架构，即模块化的激光光源通过光纤阵列的方式拼接出一个阵列照明光场，在图像显示时，每个激光器会根据画面各个区域的亮度来动态控制发光强度，而空间光调制器会根据动态的照明光场和要显示的图像内容进行相应的像素调制。另外，针对激光器波长差异导致的显示色差，提出了一种消除激光色差的区域调光算法，其主要原理是，激光器调制光强输出后，空间光调制器上的每一个像素点均根据该处混合照明光的三基色色坐标计算出对应的调制值，进而实现HDR图像的无色差显示。

Defect graphene was developed as an efficient electrocatalyst for the NRR and transformed from dopant-free graphene to N-doped graphene after the NRR.

针对某型汽油转子发动机,研制了电控单元(electronic control unit,ECU).在此基础上,着重研究了基于单转速信号的燃油喷射与点火正时控制策略.为了提高转子发动机电控系统可靠性,采用双路曲轴位置信号传感器进行了硬件电路及软件控制策略冗余设计,并且提出了相应的故障诊断方法.通过半物理仿真试验和台架试验表明:基于自主开发电子控制单元的转子发动机控制策略正确可行,发动机运转平稳.

Two-dimensional materials have large specific area, high electron transfer capability and abundant exposed active sites, which are beneficial to improve their catalytic properties. Here, we used a simple salt-template method to construct ultrathin graphene-like Fe/N-C nanosheets (named as Fe/GNS-1.5). During the synthesis process, NaCl crystallite serves as a rigid template of two-dimensional mesoscopic structure. Iron nitrate acts as a gas-foaming agent, which plays pivotal part in the morphology and structure of catalysts. The obtained Fe/GNS-1.5 nanosheets with a thickness of 3 nm have a large specific surface area (705 m(2) g(-1)). Benefiting from the structure advantages, Fe/GNS-1.5 exhibits a great bifunctional catalytic performance. The Fe/GNS-1.5 catalyst is employed as air cathode of zinc-air battery to examine its practical application, which presents excellent power density (156 mW cm(-2)) and favorable cyclic stability for more than 600 cycles.

Oxygen reduction is a significant cathodic reaction in the state-of-art clean energy devices such as fuel cell and metal-oxygen battery. Here, ZIF-incorporated hybrid polymeric fibres have been fabricated by using a dual-phase electrospinning method. These are then transformed into Co3 O4 -nanoparticle-decorated porous N-doped carbon fibres (ZIF-Co3 O4 /NCF) through multi-step annealing treatment. The resultant ZIF-Co3 O4 /NCF is interweaved into a self-supported film and can be used as a bi-functional catalyst for catalysing oxygen reduction in both aqueous and non-aqueous electrolytes. Electrochemical tests demonstrate that ZIF-Co3 O4 /NCF displays a high catalytic activity for oxygen reduction with a half-wave potential (E1/2 ) of 0.813 V (vs. RHE) and an almost favourable four-electron reduction pathway in alkaline medium. ZIF-Co3 O4 /NCF catalyst only shows 4 mV negative shift of E1/2 after 5000 continuous CV cycles. In addition, the ZIF-Co3 O4 /NCF can be applied as the cathode catalyst of non-aqueous Li-O2 battery, exhibiting a remarkable ORR activity in LiPF6 contained 1,2-dimethoxyethane electrolyte. The excellent electrocatalytic performance of ZIF-Co3 O4 /NCF is probably due to the abundance of active sites of graphitic carbon-wrapped Co3 O4 nanoparticles, as well as the cross-linked fibrous nitrogen-doped carbon texture.

During the research on the durability of oxygen reduction reaction (ORR) catalyst, we find the long-term stability test in perchloric acid electrolyte leads to an "activation effect" on the catalyst when using a Pt plate as the counter electrode. After 30,000 potential cycles, the carbon-based catalyst exhibits a positive shift of about 200 mV for the half-wave potential. By performing systemic characterization and analysis, we ascribe the " activation effect" to the deposition of Pt nano-particles onto the catalyst surface, which comes from the Pt dissolution during the potential cycling process. These results indicate the widely employed Pt wire/plate not suitable for the ORR test in acidic media, especially for stability test, which may bring about inaccurate or misleading judgments. In addition, this work also provides a novel method to decorate Pt particles on non-noble metal material to enhance the ORR activity by long-time potential cycling deposition.

A non-precious-metal catalyst, specifically made up of cobalt-embedded nitrogen-doped carbon nanotubes (Co-N-CNTs), was synthesized by subjecting a Prussian blue analogue to annealing decomposition. These Co-N-CNTs were employed as the cathode catalyst of a Li-CO2 battery, and helped this battery deliver a high capacity and outstanding cyclability. Furthermore, we verified the reversibility of this Li-CO2 battery.

Electrocatalysts with highly effective activity for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are considered to be the key factor of renewable energy technologies. Herein, we designed and synthesized bi-functional electrocatalyst Co9S8/C nanosheets (NSs) by reducing the Co3O4/C NS precursor with sodium sulfide. From the structural characterization, Co9S8 is anchored on the graphitized carbon NSs homogeneously. According to the electrochemical measurements, the Co9S8/C NSs show excellent electrocatalytic activity towards both the ORR (E-onset = 0.892 V vs. RHE and (E1/2) is 0.778 V vs. RHE) and OER (E-onset = 1.50 V vs. RHE and the overpotential is 0.434 V vs. RHE at 10 mA cm(-2)) in 0.1 M KOH solution. In the ORR, Co9S8/C catalyzes through a 4-electron process like the commercial Pt-based catalyst. In addition, the Co9S8/C NSs show great long-term stability. The Co9S8/C NSs show excellent catalytic performance due to the rich active sites and two-dimensional sheet structure. The developed strategy offers an effective method for preparing bi-functional electrocatalysts for both the OER and ORR.

We fabricated a highly effective oxygen reduction reaction (ORR) catalyst consisting of Fe/Fe5C2 species wrapped in N-doped carbon (Fe/Fe5C2@N-C), derived from annealing decomposition of a zinciferous Prussian blue analogue Zn3[Fe(CN)6]2, which can be prepared through a facile precipitation reaction. The rationally designed carbon layer-encapsulated structure with iron/iron carbide encased inside the N-doped graphitic carbon shells is favorable for ORR, wherein the iron species not only facilitate the graphitization process but also improve the ORR activity together with outside N-doped graphic carbon. The resultant catalyst demonstrates a positive half-wave potential (E1/2) of 0.85 V (vs. RHE) and a nearly four-electron pathway in 0.1 M KOH solution, comparable to that of the commercial Pt/C. With superior stability to that of Pt/C, Fe/Fe5C2@N-C suffers almost no performance attenuation after 5000 potential cycles. The zinc-air battery using Fe/Fe5C2@N-C catalyst exhibits high power density and capacity, holding great promise for the practical application of metal-air batteries.

旋翼/平尾气动干扰建模是直升机全机配平模型和飞行动力学模型的核心内容.常规全机配平模型主要通过旋翼下洗流或诱导速度等方式间接考虑旋翼对平尾的气动干扰作用,但未充分考虑旋翼对平尾非定常气动干扰产生的非线性气动载荷,因而仍难于准确体现旋翼/平尾气动干扰对全机配平特性的影响.为此本文基于非定常面元/黏性涡粒子法,通过在平尾面元中增加由旋翼和平尾尾迹时变干扰产生的非定常压力项,建立旋翼/平尾气动干扰模型,直接计算平尾非线性气动载荷,并耦合基于GA/LM混合优化的直升机全机配平方法,构建旋翼/平尾气动干扰作用下的直升机全机配平特性分析方法.通过计算UH-60A直升机的旋翼操纵量和机体姿态,并与试验测试值对比验证本文方法的准确性.通过与基于诱导速度考虑旋翼/平尾气动干扰的直升机配平结果比较表明,后者难于体现直升机低速纵向操纵量和机体俯仰角突增现象,而本文方法能较好地体现直升机低速纵向操纵量和机体俯仰角突增,且与OH-6A、EH-101等试验测量的特性一致.研究不同平尾构型对旋翼/平尾气动干扰下直升机全机配平特性的影响,分析表明低平尾产生较大的低速纵向操纵量突增,而高平尾则增加高速纵向操纵量;前置平尾产生较大的低速纵向操纵量突增,右旋直升机的右置平尾有利于减小低速纵向操纵量突增和机体俯仰角.

针对传统环境监测系统布线复杂、功耗高、设备维护不便等问题,设计一个以CC2530芯片为核心的ZigBee无线环境监测系统;该系统以CC2530为主控芯片,基于ZigBee协议栈构建无线网络实现协调器节点和现场终端节点之间数据的收发,利用串口通信技术实现协调器节点和PC机之间的通信;从系统的整体设计方案、系统的硬件设计、系统的软件设计和系统的性能测试4个方面对系统进行简单介绍;经实验证明,该系统性能稳定、实时性强、功耗低、可扩展性强,可广泛应用于对环境参数要求比较高的场合。

A novel fusion method of multispectral image and panchromatic image based on nonsubsampled contourlet transform (NSCT) and non-negative matrix factorization (NMF) is presented, the aim of which is to preserve both spectral and spatial information simultaneously in fused image. NMF is a matrix factorization method, which can extract the local feature by choosing suitable dimension of the feature subspace. Firstly the multispectral image was represented in intensity hue saturation (IHS) system. Then the I component and panchromatic image were decomposed by NSCT. Next we used NMF to learn the feature of both multispectral and panchromatic images' low-frequency subbands, and the selection principle of the other coefficients was absolute maximum criterion. Finally the new coefficients were reconstructed to get the fused image. Experiments are carried out and the results are compared with some other methods, which show that the new method performs better in improving the spatial resolution and preserving the feature information than the other existing relative methods. © Copyright.

Traffic sign detection for intelligent vehicle has become an attractive research area throughout the world. Algorithm based on traditional color space is not robust or efficient enough in complex traffic environment. Considering human vision system, we propose a new method based on opponent-color. First, the Gaussian pyramid is used to process the images in private color space. Then, the center-surround algorithm is used to enhance the color of traffic signs. Finally, the maximum area is calculated and the location of traffic signs is marked using horizontal and vertical projection of the binary image. Experimental verification shows the method has good accuracy and efficiency, which can provide efficient information for traffic sign recognition.

The purpose of remote sensing images fusion is to produce a fused image that contains more clear,accurate and comprehensive information than any single image.A novel fusion method is proposed in this paper based on nonsubsampled contourlet transform(NSCT) and region segmentation.Firstly,the multispectral image is transformed to intensity-hue-saturation(IHS) system.Secondly,the panchromatic image and the component intensity of the multispectral image are decomposed by NSCT.Then the NSCT coefficients of high and low frequency subbands are fused by different rules,respectively.For the high frequency subbands,the fusion rules are also unalike in the smooth and edge regions.The two regions are segregated in the panchromatic image,and the segmentation is based on particle swarm optimization.Finally,the fusion image can be obtained by performing inverse NSCT and inverse IHS transform.The experimental results are evaluated by both subjective and objective criteria.It is shown that the proposed method can obtain superior results to others.

针对高光谱图像的非监督目标检测问题,提出了一种基于混沌粒子群优化(PSO)投影寻踪(PP)的检测方法.混沌PSO可加快PP过程,得到更精确的最佳投影方向.利用自适应波段选择方法进行高光谱图像降维.依据对异常分布敏感的偏度和峰度设计投影指标,并采用混沌PSO搜索最佳投影方向,由此可有效地将目标信息投影至低维空间.采用直方图分割的方法从投影图像中提取出目标.针对大量图像进行了实验及检测效果的定性与定量评价,并与遗传算法PP法、RX方法的检测结果作了比较.结果表明,能够更有效地检测出高光谱图像中的目标,且所需运行时间大为减少.

In this paper, an unsupervised change detection method for multitemporal remote sensing images is proposed. Firstly, the difference image is obtained from two multitemporal images acquired on the same geographical area but at different time instances. Then the difference image is decomposed by nonsubsampled contour let transform (NSCT). For each pixel in the difference image, a feature vector is extracted using the NSCT coefficients and the difference image itself which are in the same position. The final change map is achieved by clustering the feature vectors using kernel fuzzy c-means (KFCM) clustering algorithm into two classes: changed and unchanged. The change detection results are compared with those of several state-of-the-art methods. And the experimental results demonstrate that the proposed method yields superior performance.

This paper presents a novel pedestrian detection approach. Firstly, Haar wavelet is employed to transform the input image into its sub-patterns with different resolution. And then, some relevant wavelet sub-patterns are selected to compute the fractal vector in different scales. Next, this fractal vector is assembled to be a Wavelet Fractal Signature vector, which is utilized in Support Vector Machine classifier. To validate this approach, some experiments based on Daimler's Pedestrian Detection Benchmark are conducted; the experimental results show that the proposed approach has the advantages of compact feature expression form and high detection rate.

Hot compression tests of TA15 titanium alloy with coarse lamellar microstructure were conducted using Thermecmastor-Z hot working simulator. Microstructural deformation mechanisms were investigated by means of processing map technology based on Murty criterion in the temperature range of 1 000-1 100 ℃ and strain rate range of 0. 001-10 s-1, and the forging thermal parameters were optimized. The results show that in β phase field the desired deformation regions were in the range of 1 030- 1 075 ℃ and 0.001- 0.03 s-1 with the deformation mechanism of full and uniform dynamic recrystallization, and the optimum deformation parameters were at 1 050 ℃ and 0.001 s-1. The regions of flow instability occurred in the temperature range of 1 000- 1 100 ℃ and strain rate range of 1.78-10 s-1, and non-uniform deformation of β grains appeared in this range.