混合型粗集料轻混凝土的微观结构（I）

在轻集料混凝土内,微观结构的改变,对混凝土性能的影响,目前还没有人作过系统的研究,也就是说,对于轻集料混凝土,其微观结构的具体类型、微观结构与各项理化性能之间的关系,基本上还是个空白,针对以上的具体事实,研究中采用X光（XRD）、电镜（SEM）、红外（IR）和差热（DTA）等探测手段,对所配高性能轻集料混凝土微观结构的具体类型及转化,微观结构与各项理化性能之间的关系,进行了全面的研究和测定,并着重提出：①由于陶粒的微泵作用,陶粒颗粒的内部会形成内部水化产物,除其它影响因素之外,陶粒内部水化产物的形成,将有效地提高陶粒本身和陶粒混凝土的强度。②由于界面反应,在陶粒与水泥石界面处会形成与水泥石基体相微观结构不同的9A^。托勃莫来石矿物。最后对其相应的早期水化产物及其结构特点,进行发分析和论证。     

赛罕乌拉自然保护区鸟类区系研究

１９９０－１９９９年,对赛罕乌拉自然保护区的鸟类进行了考察研究,共记录到鸟类１５０种,隶属于１７目４７科１０２属,其中６３种是夏修鸟,３８种是留鸟,１０种是冬候鸟,３９种是旅鸟。     

四位中国数学大师的创新精神及其启示

对华罗庚、丘成桐、吴文俊、谷超豪四位中国数学大师的创新精神进行了全面的分析与阐释,在此基础上得到几点重要启示.     

充填胶凝材料研究进展与金川废弃物利用展望

金川镍矿开采深度增加地压增大和品位降低,既增大采矿难度,也降低了采矿经济效益。与此同时,矿山每年排放出大量废弃物,使矿山面临严峻的环保压力。利用固体废弃物开发新型充填胶凝材料,并以此为契机,实施废弃物资源化应用,是金川矿山实现绿色开采和可持续发展的必由之路。首先,简要介绍充填胶凝材料研究进展,分析金川矿山开发新型充填胶凝材料面临的困难和问题;然后,提出利用矿渣开发金川矿山新型充填胶凝材料的技术路线与关键技术;最后,针对金川矿山镍钴资源开采与利用现状,提出以新型充填胶凝材料为突破口,开展废石、废渣、尾砂等废弃物资源化综合利用技术途径,展望金川矿山固体废弃物资源化综合利用发展前景。     

Reproductive ecology of Dusky Flycatchers in montane meadows of the central Sierra Nevada

Avian species with expansive ranges or those that occupy more than one vegetative association may vary in aspects of their life histories across their ranges. The distribution of Dusky Flycatchers encompasses a variety of vegetative associations, including riparian communities. However, much of the literature on this species details studies conducted in upland areas. Our objectives were to describe the breeding ecology and fecundity of Dusky Flycatchers nesting in montane meadows of the central Sierra Nevada, California. We monitored 36 territories and located 37 Dusky Flycatcher nests in 8 meadows. Average clutch size was 3.9 eggs. Egg laying, incubation, and nestling stages were 4, 15.4, and 16.4 days, respectively. Eighteen nests successfully fledged young, with an average of 3.3 fledglings per successful nest. Nest success was 43% and nest predation was the leading cause of nest failure. Estimated annual fecundity was 1.62 fledglings per pair; however, because all renesting attempts were not located, this should be viewed as the minimum annual fecundity. Dusky Flycatchers we monitored may have had higher fecundity than those nesting in upland areas because riparian areas often have higher arthropod abundances. While the importance of riparian conservation to riparian-obligate bird species is obvious, our study indicates that these areas also may be of value to Dusky Flycatchers that breed in riparian areas and upland areas.     

基于IMM的高动态GPS接收机载波跟踪算法

利用交互式多模型的带宽自适应调整特性实现了高动态与静态环境下通用的GPS信号载波跟踪算法。仿真结果表明,该算法在保证满足高动态GPS信号载波跟踪要求的前提下,降低了静态时的频率跟踪误差,避免了不同动态环境下多个载波跟踪算法及切换方案的设计。     

X射线衍射强度公式的修正

X射线衍射技术在物相分析、点阵参数测量以及微应力的测定等方面被广泛应用,为了更精确地确定物理参数,X射线衍射强度的精确计算是十分重要的.目前单晶X射线衍射的强度公式的理论计算结果与实验数据有较大偏差.对衍射强度公式进行合理修正,使计算结果得到较大改善,并与实验测量的数据符合得更好.     

(Nd0.62 Li0.15)TiO3陶瓷的制备及其热电性能

采用固相反应法与无压烧结法相结合制备了ABO₃型钙钛矿(Nd_0.62Li_0.15)TiO₃晶体陶瓷材料,并对其热电性能进行了表征.高分辨率透射电镜观察显示,制备的材料具有纳米超晶格结构,导致材料表现出玻璃态热传导特征且热导率小于2W/(m·K),该玻璃态热传导源于超晶格结构形成的大量纳米域界面对声子的强烈散射.A位空位填充使材料的电子电导率得到了明显改善,但对材料的热导率影响不大.塞贝克系数因为TiO₆八面体的扭曲而受到一定的影响.在测试温度范围内,块体陶瓷在500K时得到了最高的无因次热电优值(ZT)0.019.     

非正交码移键控和码索引调制算法

针对正交码移键控(code shift keying,CSK)误比特率(bit error rate,BER)性能下降和非正交码索引调制(non-orthogonal-code index modulation,N-CIM)未能充分利用扩频码自相关性的不足,提出一种非正交CSK和码索引调制(non-orthogonal...