结合伪随机特征码的多序列跳频通信方法

针对多序列跳频(multi-sequence frequency hopping, MSFH)通信系统在对偶信道存在干扰信号的情况下易引发误码的问题,提出了结合伪随机特征码的MSFH(pseudo-random feature coding MSFH, PRFC-MSFH)通信方法。在信道频率间隔内调制伪随机特征码作为信号来源的特征信息,减少对偶信道受干扰的影响,达到抗干扰目的。建立了PRFC-MSFH发射接收通信模型,根据模型推导了PRFC-MSFH在不同干扰下的误码性能。仿真结果表明, PRFC-MSFH在跟踪干扰条件下较常规跳频约有3~5 dB性能增益,在最坏多音干扰条件下较MSFH有约6~7 dB性能增益,具有较强的综合抗干扰能力。     

基于抵消技术的邻道干扰抑制

针对无线设备间的邻道干扰,提出了一种干扰抑制方法。在接收机中设计邻道干扰重建支路,利用记忆多项式估计信道的非线性参数,构建邻道干扰信号模型并重建干扰信号,最终从接收信号中消除邻道干扰信号。所提方法能够有效减小邻道干扰影响,提升期望信号接收信噪比,使有限带宽内容纳更多通信设备。计算机仿真与软件无线电平台实验结果表明,在实验室视距环境中,甚高频频段,信号带宽25 kHz,所提方法能够抑制18 dB的邻道干扰,为有限空间内无线电设备间邻道干扰抑制提供了新的研究思路。     

等效方法与等效原理

给出了等效的功能性定义,提出了结构、功能等效原理,用媒质等效法简单地导出了单色平面电磁波在良导体表面上的反射、折射特性。     

利手与注意偏向对双耳分听汉字大脑功能优势的影响

对24名左利手和24名右利手被试在三种注意条件（刺激驱动、注意左耳和注意右耳）下进行双耳分听汉字测验,检查中国人利手与汉字听觉词汇加工大脑两半球功能优势的关系,同时考察被试的注意偏向对优势效应的影响.结果表明：（1）汉语母语左利手被试加工汉字听觉词汇的大脑功能偏侧化组织明显不同于右利手;（2）右利手被试在刺激驱动条件下的右耳（左半球）优势易受注意偏向的调节出现明显波动;（3）注意偏向对左利手被试的影响主要表现为优势的左耳（右半球）成绩的下降与非优势的右耳（左半球）成绩的提高,这暗示汉语母语左利手者可能存在汉字听觉词汇加工的潜在两半球表征.     

草坪草对土壤中镉的吸收与富集作用的研究

对种植在镉污染地上草坪中镉的分布特征进行了分析测定,结果表明,草坪草不仅具有抗镉能力,而且对镉还有较强的富集能力,在停耕的镉污染农田上,种植观察草坪草,既可分散,降低镉的污染程度,改善污染的农田,又可切断镉进入食物链,同时获得可观的经济效益和社会效益,方法可行。     

电路分析的若干法则

深入分析了两套方向和两套符号，给出了完全响应分解的一种新方法，导出了米尔曼定理的对偶形式，分析了等效法则和对偶法则。     

Frequency-dependent survival in natural guppy populations

The maintenance of genetic variation in traits under natural selection is a long-standing paradox in evolutionary biology. Of the processes capable of maintaining variation, negative frequency-dependent selection (where rare types are favoured by selection) is the most powerful, at least in theory; however, few experimental studies have confirmed that this process operates in nature. One of the most extreme, unexplained genetic polymorphisms is seen in the colour patterns of male guppies (Poecilia reticulata). Here we manipulated the frequencies of males with different colour patterns in three natural populations to estimate survival rates, and found that rare phenotypes had a highly significant survival advantage compared to common phenotypes. Evidence from humans and other species implicates frequency-dependent survival in the maintenance of molecular, morphological and health-related polymorphisms. As a controlled manipulation in nature, this study provides unequivocal support for frequency-dependent survival--an evolutionary process capable of maintaining extreme polymorphism.     

Domain Decomposition Method for the Forward-Backward Heat Equation

Theheat equation arises in a remarkable variety of physical applications. A non-overlaping domain decomposition method was constructed to obtain numerical solutions of the forward-backward heat equation. The primary advantage is that the method reduces the computation time tremendously. The convergence of the given method is established. The numerical performance shows that the domain decomposition method is effective.     

两耳分听汉字测验中大脑机能优势加工的超日节律效应

对３２名听力正常的大学生被试在日间进行连续８ｈ汉语单字词两耳分听测验,以检查大脑两半球加工汉字语音机能优势的时间性动态变化。结果发现：①所有被试左、右耳正确报告的词数未见有明显的周期性波动;②有１２例被试左、右耳正确占先报告词数的优势比出现了周期约为３ｈ的超日节律;③女性被试的平均节律周期长度明显长于男性。结果提示,大脑两半球控制的分听语词加工过程在部分被试中明显受到生物钟超日节律的调节。     

电压的测量

分析了各种电压表的结构与性能特点，提出了一种提高精确度和灵敏度的新方案。