异氰酸酯树脂固定人工林杨木压缩变形的研究

采用异氰酸酯树脂对人工林杨木进行表面密实化处理,目的是固定杨木的压缩变形,改善木材的材性。结果表明:随着水溶液中树脂质量分数的增加,木材的尺寸稳定性逐渐提高。     

分形理论在农业工程中的应用

综述了分形理论在粗糙表面表征、摩擦温升分布、磨损预测模型、机器故障诊断、土壤耕作和计算机水果检测中的应用现状。     

基于植物器官尺寸检测的新型智能节水灌溉系统

针对传统节水灌溉系统存在的弊端,提出一种新型智能节水灌溉系统。这种节水灌溉系统不再以土壤的温度、湿度以及空气的温度这些间接指标作为反馈控制变量,而是以植物器官的几何尺寸作为反馈控制参数。在这种新型智能节水灌溉系统中,被控对象是植物,反馈控制参数也是植物本身,所以可实现真正意义上的闭环控制,从而提高控制精度,实现精准灌溉。     

FRACTAL DIMENSION AND DAYLIGHT INVESTIGATION

In this paper,we analyse the alylight with chaos method, and calculate the day-light illuminance fractal dimension in many kinds of sky, it proves the optical air is a chaos, and shows us the new way to study the sky Iuminance distributions.     

The Ultrafine Physical Structure Characteristics of Coal

The amorphous structure characteristics of coal and their variation regularity are discussed.The pore structure features and models of coal have been reviewed in detail.     

Construction and Realization Method for 3 -D Digital City

This paper studies the key technology in the 3 - D digital city construction, and puts forward a new method to construct and realize the 3 - D digital city. The authors discuss the dates gathering and disposal from the collection of 3 - D topograph dates, the construction and ingress of 3 - D model, the gathering and disposal of texture dates. Subsequently, to solve the problem of that the 3 - D topograph dates are greater than the 2 - D topograph, the bulk-dates optimization of 3 - D digital city is realized through the choose of appropriate DEM of linenumbers and column numbers, the 3 - D model modeling specification, the using of nodes replace, the optimization of LOD modeling. The successful operation result of Chongqing Hi-tech Development Zone 3 - D digital city project illustrates that, this system can realistic mimic status in quo of the Chongqing Hi-tech Development Zone, the system operates smoothly, and its effect is also well.     

Descending Dimension Algorithm of Nolinear Programming Problem with Linear Inequality Constraints

The general nonlinear programming with linear constraints was investigated. In the algorithm, the method of contributing set was used. Comparing with the general contributing set method, the descending dimension method was used to solve the sub-problem with equality constraints in iterative procedure and the problem with inequality constraints. The algorithm is effective by the numerical test. Finally, it was proved that the iteration points are descending, when the objective functions are convex.     

冻干物料孔隙特性表征的分形模型与分形维数

为了定量表征冷冻干燥物料孔隙结构和形貌特性，采用两种多孔介质分形模型，通过压汞法研究冻干牛肉和冻干腊牛肉孔隙结构的分形特性。研究表明：对于孔隙特征尺度为1～100 μm的冻干牛肉和腊牛肉，采用Menger海绵模型表征孔隙结构时，尽管表观上表现出无标度区分段线性的特性，却无法确定合理的分形维数用于表征物料的孔隙分形结构；而采用热力学关系模型分析物料孔隙结构时，物料孔隙呈现显著的分形特性，并可给出合理的分形维数，该方法可用于定量表征冻干物料的孔隙分形结构特性。     

Collembolan grazing affects the growth strategy of the cord-forming fungus Hypholoma fasciculare

Mycelia of cord-forming fungi show remarkable patterns of reallocation of biomass and nutrients indicating an important role of these, often extensive, organisms in the spatial translocation of energy and nutrients in forest soils. Despite the rich tradition of interaction studies between soil microarthropods and fungi, the spatial implications of these interactions, due to the potential growth responses of the fungi and to the translocation of energy and nutrients within the mycelial network, have been largely ignored. In this paper we analyse fungal growth responses in two-dimensional model systems composed of compressed soil, the cord-forming fungus Hypholoma fasciculare and three fungivorous Collembolan species. We hypothesised that (i) the highly co-ordinated nature of cord-forming fungi would lead to growth responses following collembolan grazing, and that, (ii) such changes are dependent on grazing intensity, and (iii) changes are dependent on the species grazing. Mycelial extent and hyphal cover decreased with increasing grazing density; at highest grazing density also the fractal dimension of the mycelial border decreased, indicating a less branched foraging front due to the regression of fine hyphae and the development of mycelial cords. Effects differed greatly between collembolan species although they exerted comparable grazing pressure (the smaller species were added in larger numbers according to their allometric size-metabolic rate relationships): while grazing by Folsomia candida resulted in less mycelial extension and hyphal cover, these variables were not affected when Proisotoma minuta and Hypogastrura cf. tullbergi grazed. The effects of a species mix suggested an additive effect of the component species. This shows that fungal mycelia may suffer from damage caused by few but large collembolans, affecting extension as well as coverage of the mycelium, but that fungi may compensate for the biomass loss caused by more but slightly smaller collembolans. In about 20% of the model systems H. fasciculare switched from a growth pattern with a broad contiguous foraging front and uniform growth in all directions to a pattern with fast growing sectors while other sectors stopped growth completely. The switch occurred in grazed systems exclusively; thus we interpret this observation as a fugitive response and as a strategy for quickly escaping from places where grazing pressure is experienced.     

螺纹铣削工艺的选择

总结了在数控加工中心上进行螺纹铣削的一些注意事项,其中包括螺纹铣削刀具的选用及测定、螺纹铣削底径的确定、铣削方式的选择及精度控制等。