地面反射波谱与卫星磁带记录数据间关系模拟的初步探讨──以冬小麦和土壤为例

根据冬小麦和土壤地面反射波谱测试数据，计算了在卫星高度上与卫星磁带数据相对应波段的辐亮度值，对ＮＯＡＡＡＶＨＲＲ和ＴＭ某些通道的差值绿度植被指数ＤＶＩ、归一化绿度植被指数ＮＤＶＩ和比值绿度植被指数ＲＶＩ的分析，从理论上证明了目前采用ＴＭＤＶＩ＿（４，３）提取冬小麦种植面积和ＮＯＡＡＮＤＶＩ＿（２，１）区分植被和土壤背景的有效性。同时在冬小麦种植面积和长势监测方面提出了一些新建议。     

Management of multidimensional discrete data

Spatial database management involves two main categories of data: vector and raster data. The former has received a lot of in-depth investigation; the latter still lacks a sound framework. Current DBMSs either regard raster data as pure byte sequences where the DBMS has no knowledge about the underlying semantics, or they do not complement array structures with storage mechanisms suitable for huge arrays, or they are designed as specialized systems with sophisticated imaging functionality, but no general database capabilities (e.g., a query language). Many types of array data will require database support in the future, notably 2-D images, audio data and general signal-time series (1-D), animations (3-D), static or time-variant voxel fields (3-D and 4-D), and the ISO/IEC PIKS (Programmer's Imaging Kernel System) BasicImage type (5-D). In this article, we propose a comprehensive support ofmultidimensional discrete data (MDD) in databases, including operations on arrays of arbitrary size over arbitrary data types. A set of requirements is developed, a small set of language constructs is proposed (based on a formal algebraic semantics), and a novel MDD architecture is outlined to provide the basis for efficient MDD query evaluation.     

Processing and microstructure of non-oxide ceramic fibres

Research and development efforts on high-temperature, oxidation-resistant fibres have increased over the past decade due to the demand for light-weight, stiff and strong composite materials in aerospace applications. Varieties of ‘high-performance’, continuous, non-oxide fibres with low-density, high tensile strength and tensile modulus have been developed either from organic precursors or via chemical vapour deposition for fabrication of ceramic matrix composites. Fibres derived from polymer precursors (e.g. Nicalon, Tyranno, HPZ) are small in diameter (compared to CVD monofilaments) and are ideally suited for ceramic composites. Processing, microstructural stability and mechanical properties of these newly developed SiC and Si₃N₄ base fibres are briefly reviewed in this paper.     

氢电弧等离子体法制备的纳米镍铈粒子的催化特性

利用氢电弧等离子法制备具有储氢特性纳米镍铈粒子，并在气相苯加氢反应中研究了其催化特性，发现其催化活性与储氢特性及表面层中ＮｉＣｅ合金存在有关，且具有高的选择性和热稳定性，这与纳米粒子独特的结构及铈的加入有关。     

低频电脉冲采油工程设备的开发与应用

低频电脉冲采油技术是通过升压、整流、充电等电路将电能蓄积在电容器中,通过触发电路,使能量瞬时释放,在井内液体中产生震动波,作用于地层,改善地层的渗流状况,达到提高采收率的目的。Ⅰ型设备在双河油田应用11井次,成功率72%;Ⅱ型设备在古城油田应用10井次,成功率90%。主要是由于Ⅰ型设备关键部件在处理油井时要放在井下,受高温、高压的影响及井下空间的限制,设备稳定性差、寿命短、能量小、效果差;Ⅱ型设备解决了上述问题,从而提高了试验成功率。     

微型无阀泵参数化结构设计及测试

 从理论计算和试验两方面研究了用于微流控化学分析芯片的微型无阀泵流动特性，初步建立了微型无阀泵流道结构的数学模型，重点讨论了结构参数的选取原则及相应的流动阻尼系数的计算方法． 通过试验验证了数值计算的可靠性，为微型无阀泵参数化设计及优化提供了理论依据及经验曲线．     

不动管柱换层采油工艺技术与应用

胜利油田已进入高含水中后期采油阶段 ,应用新开发的不动管柱换层采油工艺技术 ,取得了很好的分层开采效果。对这项工艺技术的分析表明 ,该项工艺技术的创新点在于 :(1)管柱满足直井、大斜度井、定向井机械控水的使用要求 ;(2 )设计了密封可靠、解封安全的Y4 41E型液压封隔器及其配套工具 ;(3)YK型液压换层开关换层可靠 ,性能稳定 ;(4)可随意换层生产 ,减轻了层间生产矛盾 ,降低了作业成本。     

秸杆材料用作草皮栽培基质的研究

本文介绍了秸杆毡的成型工艺 ,通过植物所需的水、肥料和空气三种因素对秸杆毡的化学和物理性能进行了研究 ,该材料可被用作草皮栽培基质     

现场总线技术在城市污水处理与气象中的应用

文章主要讨论了LonWorks现场总线技术在城市污水处理厂和气象指数预报中的应用。采用IPC和PLC控制结构对现场的各种设备实现控制和数据的采集，通过现场总线网络传输数据到中心控制室或远程终端，实现污水处理的自动控制和气象信息的实时采集和处理。     

分析矩形光波导损耗的简易方法

利用有效折射率和修正的有效折射率方法对矩形光波导的损耗作了简单有效的分析，并且计算出了纵向传播系数和衰减系数的大小。