黄河水资源利用现状,预测及对策

人民治黄以来，黄河流域修建了大量的蓄，引，提水工程，为黄河水资源的开发利用创造了良好的条件，１９９０年流域工农业总引用水４７８亿ｍ＾３其中地下水１１４亿ｍ＾３，河川水３６４亿ｍ＾３，用水量最多的是农业灌溉，工业及生活用水比重较小，据分析，２０００年水平全流域总需水量６４０亿ｍ＾３年供水量为６２０亿ｍ＾３，缺水２０亿ｍ＾３，２０１０年水平全流域总需水量为７２３亿ｍ＾３，在满足下游输水入海用水条件下，     

黑龙江省移动基站动力及环境集中监控系统

介绍了黑龙江省移动基站集中监控系统网络结构、系统功能、监控对象及供电方式，并探讨了黑龙江省移动基站动力及环境集中监控系统的传输方案。     

强直流场下空气等离子体产生的太赫兹波的特性研究

研究了强直流偏压场下的800 nm飞秒激光电离空气等离子体产生的太赫兹波.通过改变直流偏置场的方向,使之垂直或平行于泵浦光偏振方向,对太赫兹波的偏振特性进行了系统的研究.研究结果表明太赫兹波的产生是有质动力和直流偏置场的共同作用结果,外直流偏置场能够放大和调制总的太赫兹波.     

含有损耗双负介质的棱镜波导中古斯汉森位移特性研究

研究含有损耗的双负介质导波层的棱镜波导耦合系统中的古斯汉森(Goos-H?nchen,GH)位移增强效应。采用稳态相位理论得出了GH位移的表达式,并推导出获得较大GH位移的充分条件;通过仿真分析,研究了介电常数、包层和导波层的厚度对GH位移的影响,同时验证了增强GH位移的充分条件的有效性。结果表明,利用双负介质做棱镜波导系统的导波层可以有效克服材料自身带来的损耗,实现较大值的GH位移;同时,系统中的GH位移极大值对包层和导波层的厚度的微弱变化(1纳米)十分敏感,可用来制作高灵敏度的表面平整度探测器。     

Proactive content caching by exploiting transfer learning for mobile edge computing

To address the vast multimedia traffic volume and requirements of user quality of experience in the next‐generation mobile communication system (5G), it is imperative to develop efficient content caching strategy at mobile network edges, which is deemed as a key technique for 5G. Recent advances in edge/cloud computing and machine learning facilitate efficient content caching for 5G, where mobile edge computing can be exploited to reduce service latency by equipping computation and storage capacity at the edge network. In this paper, we propose a proactive caching mechanism named learning‐based cooperative caching (LECC) strategy based on mobile edge computing architecture to reduce transmission cost while improving user quality of experience for future mobile networks. In LECC, we exploit a transfer learning‐based approach for estimating content popularity and then formulate the proactive caching optimization model. As the optimization problem is NP‐hard, we resort to a greedy algorithm for solving the cache content placement problem. Performance evaluation reveals that LECC can apparently improve content cache hit rate and decrease content delivery latency and transmission cost in comparison with known existing caching strategies.     

基于Simulink的箔条走廊干扰仿真系统

采用Simulink仿真技术,对箔条走廊干扰过程和干扰效果进行了动态的信号级仿真。进行了作战场景想定,建立了箔条走廊对雷达干扰的模型体系结构,给出了仿真模块框图。给出了箔条走廊干扰的原理及数学模型,对仿真结果进行了对比分析。仿真结果表明,箔条走廊散射杂波可以压制常规脉冲雷达,箔条走廊对电磁波的衰减可以使MTD体制雷达接收不到目标回波。     

Self‐Assembled In‐Plane Growth of Mg2SiO4 Nanowires on Si Substrates Catalyzed by Au Nanoparticles

In‐plane growth of Mg₂SiO₄ nanowires on Si substrates is achieved by using a vapor transport method with Au nanoparticles as catalyst. The self‐assembly of the as‐grown nanowires shows dependence on the substrate orientation, i.e., they are along one, two, and three particular directions on Si (110), (100), and (111) substrates, respectively. Detailed electron microscopy studies suggest that the Si substrates participate in the formation of Mg₂SiO₄, and the epitaxial growth of the nanowires is confined along the Si <110> directions. This synthesis route is quite reliable, and the dimensions of the Mg₂SiO₄ nanowires can be well controlled by the experiment parameters. Furthermore, using these nanowires, a lithography‐free method is demonstrated to fabricate nanowalls on Si substrates by controlled chemical etching. The Au nanoparticle catalyzed in‐plane epitaxial growth of the Mg₂SiO₄ nanowires hinges on the intimate interactions between substrates, nanoparticles, and nanowires, and our study may help to advance the developments of novel nanomaterials and functional nanodevices.     

利用开菲尔发酵剂制备牛乳酸马奶酒的研究

对利用生产酸牛乳酒（Ｋｅｆｉｒ）的发酵剂（ＫｅｆｉｒＣｕｌｔｕｒｅ）制备牛乳酸马奶酒（或称模拟酸马奶酒）进行了研究。利用全牛乳、脱盐乳清及植物油、ＶＣ按一定比例配合制得的模拟马乳其主要成分接近马乳的化学组成。制得的模拟马乳用ｋｅｆｉｒ发酵剂进行发酵，经１２ｈ的发酵，其中乳酸含量为０．７３－０．７８％；乙醇含量为０．０２１％－０．０２８％，随发酵的进行，其中ＮＰＮ含量逐渐增多，产品中的游离氨基酸含量     

An experimental study on the universality of visual vocabularies

Bag-of-visual-words has been shown to be a powerful image representation and attained success in many computer vision and pattern recognition applications. Usually for a given classification task, researchers choose to build a specific visual vocabulary, and the problem of building a universal visual vocabulary is rarely addressed. In this paper we conduct extensive classification experiments with three features on four image datasets and show that the visual vocabularies built from different datasets can be exchanged without apparent performance loss. Furthermore, we investigate the correlation between the visual vocabularies built from different datasets and find that they are nearly identical, which explains why they are universal across classification tasks. We believe that this work reveals what is behind the universality of visual vocabularies and narrows the gap between bag-of-visual-words and bag-of-words in text domain.