偶氮苯类有机小分子纳米粒子的制备及表征

以十六烷基三甲基溴化铵(CTAB)为稳定剂和模板,利用再沉淀法制备了偶氮苯类有机小分子2-(4-羟基苯基-偶氮)苯甲酸(HABA)的纳米粒子,并用紫外—可见吸收光谱(UV-vis)、扫描电镜(SEM)和圆二色谱(CD)等测试手段对其进行了表征.结果表明:制备的HABA纳米粒子为带状,在无手性诱导剂条件下制备的纳米粒子表...     

请为国产汽车设计雨刮器喷水装置

今年以来,全国各地车辆事故每月均呈上升趋势。我是一名汽车驾驶员,对目前各级交通部门为狠刹交通事故,积极开展的各种安全活动是赞赏的。然而,赞赏之余,我认为还必须改善国产汽车的一些机械装置设计。比如,目前国产汽车(不论是轿车,旅游车,还是载货车)都没有前挡风玻璃喷水装置。汽车行驶途中,遇到挡风玻璃脏了,     

汽车制动钳体所需液量的检测与浅析

介绍了微型轿车系列盘式制动器性能试验中所需液量的检测与分析，所需液量指钳体内压入液体容积与压力上升的关系，所需液量的多少即指达到同等压力下钳体内所需压入液体的容积大小。经过几年的试验探索，找出了一套操作简单、方便及测试精度高的所需液量测试方法。另外，阐述了影响所需液量的因素。     

An improved cyclostationary feature detection based on the selection of optimal parameter in cognitive radios

Spectrum sensing is an important part of cognitive radio systems to find spectrum hole for transmission which enables cognitive radio systems coexist with the authorized radio systems without harmful interference. In this paper, an improved cyclostationary feature detection method is proposed to reduce computational complexity without loss of good performance based on the optimal parameter selection strategy for choosing detection parameters of cyclic frequency and lag. Taking binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) signals as examples, the theoretical analyses are presented for choosing the optimal parameters. Simulation results are given to certify the correctness of the proposed parameter selection strategy and show the performance of the proposed method.