A Novel Athermal 40-Channel DWDM Multi/Demultiplexer Based on the Combination of AWGs and Interleaver

An athermal 40-channel dense wavelength-division-multiplexing multi/demultiplexer using a novel combination technology is proposed. It consists of one 1times4 100- to 400-GHz spacing interleaver filter and four sub-arrayed-waveguide gratings (AWGs). The temperature-dependent wavelength shift of the combined device is successfully suppressed to 0.058 nm in the -20degC to 70degC temperature range. Moreover, the combined device's adjacent crosstalk (typically -35 dB) is much better than conventional AWGs (typically -25 dB).     

宝鸡市医用诊断X线照射频度调查

本文报道从1984年6月1日至1985年5月31日对宝鸡市五县(区)医用诊断 X 线照射频度的调查结果。结果表明,胸透和群检胸透医照率最高,占医疗照射总人次数的68.7%,门诊医照率为70.8人次/千人·年,人群受照率为344。5人次/千人·年。按年龄比较,青壮年组医照率最高,占医照总人次数的57.2%。按性别比较,男性多于女性。     

秦岭造山带（陕西部分）中新生代陆内造山及与矿产关系

印支运动后的秦岭造山带受古亚洲构造域、环太平洋构造域和特题斯三大构造域联合作用，发生了强烈的陆内造山，奠定了该区条块相间构造岩片系统的基本构造格架，控制了本区斑岩型钼矿和众多热液型多金属矿产的最终成矿作用和矿带展布。     

A Subcarriers Allocation Scheme for Cognitive Radio Systems Based on Multi-Carrier Modulation

Cognitive radio (CR) is a dynamic spectrum access technology as a solution to spectrum under-utilization problem in some licensed bands. Operating over an exceedingly wide spectrum, CR systems usually adopt multi-carrier modulation (MCM) to implement flexible channelization. Consequently, efficient channel allocation scheme becomes extremely important to an MCM based CR (MCM-CR) system. In this paper, a maximum likelihood detection model is developed to detect the presence and locations of licensed users (LUs) signals in the frequency domain. Performance of the detection model, including the optimal detection region, detection probability and false alarm probability, is analyzed. A one-order two-state Markovian chain model is proposed to predict channel status information. In particular, a novel subcarrier allocation scheme for MCM-CR systems is proposed, taking into account the confidence of channel estimation, quality of services (QoS) of rental users (RUs) and throughput. To validate the analytical results, simulations have been conducted to show effectiveness of the proposed scheme.     

KATRIN NEG pumping concept investigation

The Karlsruhe Tritium Neutrino experiment (KATRIN) is going to use a very large electro-static tandem spectrometer to measure the electron spectrum from the tritium beta decay, where several kilometers of non-evaporable getter (NEG) strips (type ST707) are to be used to achieve the UHV requirements. Different geometrical configurations of the NEG strips have been studied by Monte Carlo simulations. It is shown that the resulting pumping speed of the getter pumps will allow to get a pressure below 10⁻¹¹ mbar in the huge vessel with a volume of 1400 m³. By systematic assessment of the statistics of the pumping surfaces, it could be demonstrated that the design is sound.     

奥里油在电力工业的应用及环保处理

委内瑞拉富藏奥里油约469亿t，中国政府与委内瑞拉政府签订了合作生产和供应每年650万t奥里油的合作协议。介绍了奥里油的特性和在全球以及中国的应用情况，分析了奥里油燃烧发电带来的特殊的环保问题和处理方法。     

青海省桥头电厂河子沟灰场拦洪坝粘滞流模型试验分析

本文采用粘滞流模型试验对青海桥头电厂河子沟灰场拦洪坝设计方案进行了论证，分析了多种防渗条件下的渗流场特点，提出了满足工程运作的既经济又合理的建议。     

Effect of heat treatments on tensile properties and microstructures of wrought Mg−Zn−Zr-RE alloys

The effect of heat treatments on the tensile properties and microstructures of wrought Mg–Zn–Zr-Rare earth alloys MB25 and MB26 have been studied in this paper. It was shown that the homogenization of the cast ingots decreased the strength of the extruded bars because some grain boundary phases were dissolved during the process of this treatment, while the ageing treatment of the extruded bars increased the strength due to the dispersive precipitation of MgZn₂ phase. The quenching + ageing treatments of the extruded bars decreases the strength and plasticity because of the growing up of the grains.Abbreviations ED electron diffraction - GB grain boundary - RE rare earth - TEM transmission electron microscope