某鱼雷空中姿态控制装置自动测试系统的设计

通过对某鱼雷空中姿态控制装置进行分析与研究,并对被测对象测试需求特征进行综合分析,优化测试项目,优化测试资源配置,设计出适用的空中姿态控制装置测试设备。测试仪硬件采用基于ISA总线结构的工控机,软件采用LabWindows/CVI开发平台。     

Nanostructure effect of V2O5 buffer layer on performance of polymer-fullerene devices

Nanostructure of solar cell materials is often essential for the device performance. V₂O₅ nanobelt structure is synthesized with a solution process and further used as an anode buffer layer in polymer solar cells, resulting insignificantly improved power conversion efficiency (PCE of 2.71%) much higher than that of devices without the buffer layer (PCE of 0.14%) or with V₂O₅ powder as the buffer layer (1.08%). X-ray diffraction (XRD) results indicate that the V₂O₅ nanobelt structure has better phase separation while providing higher surface area for the P3HT:PCBM active layer to enhance photocurrent. The measured impedance spectrums show that the V₂O₅ nanobelt structure has faster charge transport than the powder material. This work clearly demonstrates that V₂O₅ nanobelt has great potential as a substitute of the conventionally used PEDOT-PSS buffer layer for high performance devices.     

Detection of OFDM Signals in Fast-Varying Channels With Low-Density Pilot Symbols

In fast-varying channels, an orthogonal frequency-division multiplexing system needs to insert denser pilot symbols among transmitted symbols in tracking the variation of a channel. However, using denser pilot symbols reduces transmission throughput. In this paper, we propose a pseudopilot algorithm for data detection in fast-varying channels without increasing the pilot density. Our algorithm is based on a regressional model-based least-squares-fitting approach. Within a block of received symbols, we select some data symbols and regard them as pseudopilot symbols. The receiver considers all the possible patterns of the pseudopilots and associates each of them with a data sequence and a corresponding metric. The associated data sequence, whose metric is minimum, is selected as the detected data sequence. Our algorithm is not based on a decision-directed or decision-feedback architecture because the pseudopilots do not come from any detected symbols. The proposed algorithm needs to search all the possible patterns of the pseudopilots, and the complexity may increase with the number of pseudopilots and constellation size. To reduce the number of search, we further propose two modified approaches. The simulation results show that the performance of the proposed algorithms could approach a bit-error probability lower bound that is obtained by letting the receiver know the true values of the pseudopilots. Compared with the linear interpolation method, the proposed algorithm shows obvious improvement in fast-varying channels. The proposed modified approaches could also effectively reduce the number of search while maintaining the performance. We also give the complexity analysis of the proposed algorithm and an approach to determine the degree of the regression polynomial.     

Engineering of charge transport materials for universal low optimum doping concentration in phosphorescent organic light-emitting diodes

A universal low optimum doping concentration of below 5% was demonstrated in phosphorescent organic light-emitting diodes (PHOLEDs) by managing the energy levels of charge transport materials. The device performances of PHOLEDs could be optimized at a low doping concentration of 3% irrespective of the host material in the emitting layer. The suppression of charge trapping and hopping by the dopant through charge transport layer engineering optimized the device performance at low doping concentration. In addition, it was revealed that PHOLEDs with low optimum doping concentration show better quantum efficiency, low efficiency roll-off and low doping concentration dependency of the device performance.     

椭圆曲线密码体制数字签各卡的实现

数字签名是电子商务安全可靠的重要技术手段.在介绍了数字签名原理和椭圆曲线密码体制基础上,针对椭圆曲线算法具有密钥短、安全强度高、计算量小,智能卡具有体积小、便于携带、具备一定数据存储和数据处理能力等特点.采用Infineon公司的SLE66CL160S智能卡实现了基于椭圆曲线算法的数字签名卡设计,给出了设计中应用的文件结构、自定义指令、数据交换协议及签名、验证流程等,并通过合理选取参数验证了设计的可行性.     

A low-voltage, low-power CMOS delay element

A low-voltage, low-power CMOS delay element is proposed. With a unit CMOS inverter load, a delay from 2.6 ns to 76.3 ms is achieved in 0.8 μm CMOS technology. Based on a CMOS thyristor concept, the delay value of the proposed element can be varied over a wide range by a control current. The inherent advantage of a CMOS thyristor in low voltage domains enables this delay element to work down to the supply voltage of 1 V while the threshold voltage of the nMOS and pMOS transistors are 840 mV and -770 mV, respectively. The designed delay value is less sensitive to supply voltage and temperature variation than RC-based or CMOS inverter-based delay elements. Temperature compensation and jitter performance in a noisy environment are also discussed     

国产钢丝绳产品质量不稳定因素分析

对比国内外钢丝绳产品,从制造钢丝绳原料的化学成分、金相组织,钢丝拉拔、热处理工艺及设备,钢丝绳设计、生产控制及使用维护等方面,阐述国产钢丝绳质量不稳定的因素,指出国内钢丝绳制造厂家应加强钢丝绳配套设备的研究,尽快缩小与国外钢丝绳产品的差距。     

航向角BP神经网络自整定PID控制算法仿真

设计了基于BP神经网络的自整定PID控制算法,此控制算法不需要被控对象的数学模型,先由BP神经网络对被控对象进行辨识,给出PID控制所需要的3个参数,再由PID控制算法进行有效的控制,最后用MATLAB对某水下机器人的航向角模型进行了仿真验证。     

安家岭露天矿台阶爆破质量优化研究

为了提高安家岭露天矿煤岩台阶的破碎效果,降低爆破成本,比较深入地分析和研究了岩体的节理裂隙、孔网参数的布置、起爆方式以及台阶深孔爆破装药技术等几种因素对台阶爆破效果的影响。针对该矿在爆破生产过程中遇到的拉底和大块问题,通过改变和调整孔网参数、装药结构、炸药单耗、起爆药包位置及微差间隔等技术措施,改善了煤岩台阶的破碎效果。实践表明,这些爆破技术的优化提高了该矿的综合生产效率,也使开采成本得到了一定的控制。     

改进的代理多重签名方案

Ji和Li提出的一种基于椭圆曲线离散对数问题的代理多重签名方案存在两个问题：a）安全性,该方案的签名验证数据中没有避免孤悬因子这一现象,因此并不满足强不可伪造性,任意一个原始签名者能伪造代理多重签名;b）效率,代理多重签名的长度和验证其签名效率与原始签名者的个数有关。对Ji-Li代理多签名方案的安全性和效率进行了分析,提出了新的、安全的基于椭圆曲线离散对数问题的代理多签名体制,提高了签名验证效率、缩短了签名长度。