栽培介质、pH值和氮形态对毛竹幼苗地上部分生长的影响

为进一步明确毛竹幼苗无土栽培的最佳条件,阐明毛竹N形态响应差异的影响因素,加快毛竹实生苗的培育.研究超纯水、砂和蛭石3种栽培介质,2 mM不同N形态(NH4+-N、NO3--N)以及3种pH值(3.8、5.8、7.8)处理对毛竹幼苗地上部的苗高、叶片数、叶绿素相对含量(SPAD)及地上部生物量的影响.结果表明:在蛭石和水培时,毛竹生长表现出明显的喜铵性,并且在pH为3.8时生长最好;而砂培时,毛竹幼苗生长对NH4+-N和NO3--N以及pH的响应差异都不明显.相关性分析结果表明,对地上部生长的影响为:栽培介质>pH值>N形态.毛竹幼苗生长及对不同N形态的响应受外界环境条件影响,在蛭石中栽培,供应NH4+-N为主、pH值为3.8的营养液,其生长最好.研究结果可为毛竹幼苗的无土栽培和繁育提供理论参考.     

基于RS与GIS的山东某煤矿区历史遗留损毁土地调查

我国地域辽阔，但可利用土地资源少，同时由于生产建设和自然灾害等，造成许多优质土地资源损毁。调查清楚土地损毁情况，采取针对性的土地复垦措施，在目前经济发展中显得尤为迫切。以山东某矿区为例，确定了历史遗留损毁土地的划定依据，利用RS与GIS等技术手段对矿区进行地表沉陷预计，用遥感影像提取土地利用变化情况，得到了历史遗留损毁土地的位置、面积和损毁类型等信息，为后期土地复垦与规划提供参考。      

景泰绿洲3种小谷物的产草量与牧草营养成分预测

为了预测景泰绿洲春小麦(Triticum aestivum)、燕麦(Avena sativa)、黑麦(Secale cereale)的产草量和营养品质,通过田间试验,测得牧产草量、株高和分蘖,室内测定粗蛋白、粗脂肪、中性洗涤纤维、酸性洗涤纤维、粗灰分和可溶性碳水化合物,分析各指标之间的相关性。结果表明,收获干草的3种小谷物分蘖和株高均与可溶性碳水化合物之外其它5个营养指标存在显著相关性(P0.05),模拟轮牧的春小麦和黑麦株高与营养指标均无相关性(P0.05),燕麦和黑麦的分蘖与6个营养指标均呈显著相关(P0.05)。建立了根据株高预测产草量和营养品质的模型、用分蘖预测牧草营养品质的模型、用产草量预测牧草营养品质的模型、用分蘖和产草量两个因子综合预测营养品质的模型。经过与实测值对比,各预测模型的准确性均较高。     

Design and Experiment of Slave Computer Control System for Applying Variable-rate Liquid Fertilizer

In order to increase the applying rate of liquid fertilizer and reduce environmental pollution, a slave computer control system for applying variable-rate liquid fertilizer was designed. The system used SMC as core processor and electrically controlled pressure regulator as execution component. The characteristic equation of the system was obtained by using classical control theory. Results indicated that the characteristic equation met the requirements of routh-criterion, which indicated the working process of the system was stable. Performance of the slave computer was verified via bench tests. Results demonstrated that there was no significant influence on the response from interclass error. The fertilization error was less than 0.9, and the fertilization accuracy was larger than 97%. The liquid fertilizer emitted by the fertilizing devices had no significant difference in uniformity, which met the demands of the slave computer control system for applying variable-rate liquid fertilizer.     

基于ODBC技术的庭院可视化远程灌溉系统设计

水是制约可持续发展最重要的因素,而家庭灌溉将很快成为城市的用水大户,如何从硬件技术上实现节约有限的水资源关系到眼前以及未来的发展。为了解决城市用户需水量不断增加和水资源相对匮乏的现状,提供了一种可视化精确灌溉系统,该系统以MySQL数据库为中间媒介,利用Internet作为信息远程传输载体,通过一些特别的对象集合如ODBC来进行数据库连接,利用高级程序语言VB.NET实现数据库的调用。该系统经过长期调试,能够较好地完成灌区的管理,实现节水灌溉。     

高阶椭圆锥齿轮泵的流量特性

针对齿轮泵的变量功能及非圆锥齿轮的应用,提出了一种新型相交轴变量齿轮泵——高阶椭圆锥齿轮泵.该齿轮泵是以高阶椭圆锥齿轮为工作转子的非圆锥齿轮泵.根据齿轮的空间啮合原理,给出了其工作转子高阶椭圆锥齿轮副的齿形生成方法.基于该种齿轮特殊的运动学特性,分析了高阶椭圆锥齿轮泵的传动特性,并对其工作结构进行了设计.依据球面微分理论,推导出了高阶椭圆锥齿轮泵的平均理论流量公式、瞬时流量公式以及流量脉动公式,同时分析了高阶椭圆锥齿轮的偏心率、阶数等参数对其流量特性的影响.在同等参数模型及工况条件下,将对高阶椭圆锥齿轮泵的平均理论流量、瞬时流量及其变量范围与圆柱齿轮泵和非圆柱齿轮泵的流量特性进行了对比分析,获得了该锥齿轮泵在同等条件下排量最大、变量范围最大的特点.     

离合式行星齿轮减速器的研制

针对我国大中型拖拉机及收割机现用行星齿轮减速器不能离合的现状,设计了离合式行星齿轮减速器。介绍了离合式行星齿轮减速器的设计思路、结构形式和性能参数及主要特点,重点综述了离合式行星齿轮减速器离合装置的结构设计优化及使用效果,为各种大中型拖拉机及收割机行星齿轮减速器改进设计,开创新思路。     

生啤酒膜法过滤除菌技术的试验研究

阐述了生啤酒膜法过滤除菌技术的试验研究方法。着重讨论了膜孔径的选择试验及操作压力，主流液流速对浓差极化和渗透通量的影响，运用二次回归正交组合设计的方法建立数学模型，寻求操作参数的最佳值，并初步探索了膜的再生方法。     

The rehabilitation of an irrigation system along the Yellow River

The People's Victory Irrigation System which diverts water from the Yellow River of China covers a total irrigable area of 59 000 ha. The system encountered some serious problems in the first decade of its operation — salinity and waterlogging of irrigated land, siltation of irrigation and drainage channels, as well as a low efficiency of water use. This paper describes a series of structural and functional measures which have been adopted in the past 24 years for the rehabilitation of the system, including: improvement of the existing drainage system and construction of new drainage system on agricultural land, conjunctive use of surface and groundwater supplies, a comprehensive programme to reduce the levels of siltation as well as the implementation of improved water management practices. A model for the optimal operation of the system by using system analysis theory as an aid in reducing the operation and maintenance (O & M) costs has been developed in recent years. The results are that the soil salinity has been controlled and the agricultural production has increased whilst the efficiency of water use has improved and the siltation levels reduced. Experience gained on this system has been successfully used in developing and managing other irrigation projects along the lower reaches of the Yellow River. The proposed procedure of solving the said optimal model has also embodied some benefits from reducing O & M costs in operation.