基于短时傅里叶变换的干扰信号识别方法

目的提高无线电引信识别欺骗式干扰的能力。方法根据炮弹弹体自旋的特点,使得采用连续波线极化天线的无线电引信所收到的干扰信号呈现出有别于地面回波的周期性幅度调制特征,通过对此特征进行短时傅里叶变换后进行识别,可以作为无线电引信是否受到欺骗式干扰的判断依据。结果通过仿真和试验对方法的可行性进行了验证,表明该识别方法可以很好地提高连续波无线电引信的识别欺骗式干扰的能力。结论基于短时傅里叶变换检测旋转调制的对地旋转弹无线电引信欺骗干扰识别的方法可以对干扰信号特征进行识别,算法处理时间短,能够作为引信是否受到干扰的一种判断依据。     

黔中地区二级阶地堆积物边坡稳定性对工程建设的影响

结合在建工程清水河大花水电站实例,本文对黔中地区二级阶地堆积物边坡成因、堆积物物质成份、结构与其物理力学特性作了分析、总结,初步探讨了贵州省二级阶地堆积物边坡稳定性对工程建设的影响,望能给正在进行工程建设的同行以一定的参考,并对工程建设区的二级地堆积物边坡稳定性引起重视。     

城市大气污染物浓度预测模糊识别理论与模型

根据大气污染物的浓度具有模糊性且与多种指标相关的特点，提出对其进行预测的模糊识别理论与模型，并以二氧化硫为例，由２５个预测点大气中ＳＯ２浓度和相关指标的实测资料，利用上述理论与模型得出最优模糊预测参数，并对其它５个观测点的ＳＯ２浓度进行了预测检验。     

铝和铁共聚物的组成与结晶形貌

通过扫描电镜对铝，铁均聚物与共聚物样品的观察，不同Ａｌ／Ｆｅ的能谱点测定，其晶形貌象进行了比较，并探讨其共聚合作用的机理，为深入研究铝，铁无机共聚合物特性及絮凝效能提供了基础依据。     

粒子图像测速技术在往复隔板絮凝池中的应用

由于往复隔板絮凝池廊道狭窄、絮凝池拐弯水流结构复杂,致使整个流场的量测十分困难。采用了粒子图像测速技术,对其流场进行了量测与相关分析,提高了分析结果的准确性和可靠性。     

The superseded female's dilemma: ultimate and proximate factors that influence guarding behaviour of the carpenter bee Xylocopa pubescens

Both solitary and primitively social nests of the facultatively social carpenter bee Xylocopa pubescens can be found throughout most of the breeding season. In social nests there is reproductive division of labour between a dominant forager and a guarding female. Two types of guarding females can be discerned: the young pre-reproductive guards, and older, formerly reproductive guards. The latter type of guard is found when, after a take-over of reproductive dominance either by a nestmate (mostly a daughter) or an intruder, the defeated female stays in the nest instead of leaving to try and found or usurp another nest. She is then manipulated into the role of a guard. The dominant female profits from the presence of the guard since she protects the nest against pollen robbery by conspecifics (Hogendoorn and Velthuis 1993). We have studied why superseded females might prefer to remain as a guard, rather than try their luck somewhere else. The hypotheses investigated pertain to (1) the difficulty for the defeated female of finding a new nest and of restarting reproductive activities due to (a) ecological constraints (nest and pollen shortage) and (b) the effect of age and wear on the defeated female; (2) the effects of guarding in terms of inclusive fitness. We found that superseded females remained as guards significantly more often when a nestmate (not necessarily close kin) took over reproductive dominance than when an intruder did so. Other factors associated with the decision of the defeated female to stay or leave were her age and the number of her own young still present after the supersedure. The probability of finding or constructing a new nest was lower for old than for young females. After finding a nest, old females produced less brood than young foundresses. As a result of these two factors old superseded females gained, in terms of inclusive fitness, by staying as guards, whereas young females profited from leaving the nest. We interpret these results as an indication that guarding behaviour has evolved due to kin selection. However, kin discrimination apparently did not occur. Therefore we conclude that in this species kin selection is not, in the proximate frame of reference, based on kin recognition and preference for helping kin. Correspondence to: K. Hogendoorn     

爆堆块度评价方法研究的进展

爆堆矿岩的块度分布是评价爆破效果的一项重要依据。对爆堆矿岩的块度大小与块度构成情况进行准确、可靠的定量描述 ,不仅可为验证、改进爆破工艺与参数 ,进而为改善爆破效果提供直接的参考依据 ,而且也是开展爆破优化研究的重要技术基础。通常使用手工方法去评估爆堆矿岩的块度 ,它能在一定程度上对爆破块度分布进行定量的评价。但这些方法还都存在着某些缺陷。而爆堆矿岩块度的计算机图像分析法则可弥补上述诸方法的种种缺陷 ,近年来 ,该研究在国内外得到了越来越广泛的关注和应用。笔者在总结各种测定爆破块度分布的理论和方法的基础上 ,详细分析和研究了当前计算机图像处理分析爆破块度方法。     

小径薄壁管射线透照布置方法

小径薄壁管广泛用于工艺管道中，在对其进行无损探伤时，一般采用双壁双影椭圆成像法和双壁重叠成像法，针对小径薄壁管对接焊缝透照成像的特殊要求，具体介绍双壁双影椭圆成像法的透照布置方法。     

高层建筑物附近架空高压输电线路的走廊问题

采用镜像法实例计算了高层建筑物附近架空高压输电线路的工频电场和无线电干扰场强，并从电磁环评的角度对输电线路走廊的选择提出了一些建议。     

灾害发生时影响居民心理承受能力的社会心理因素分析

目的：探讨影响个体面对自然灾害时心理承受能力的社会心理因素．方法，采用问卷调查的方式，运用因素分析法和相关分析法对1000余名居民进行测评．结果。①个体面对灾害时的心理承受能力的影响因素为。灾害意识、灾时行为、灾害认知、社会支持，②通过相关分析，灾时行为对心理承受能力的影响最大。