关于黑龙江省冷害风险的生产经营模型的研究

考虑黑龙江省水稻冷害的生产特点,根据预报的气象资料,利用品种的不同特性及多样性,根据价格变动和收益变动,采用日本大石亘研究的已经应用于生产的线性模型,利用电脑XLP的操作系统来组合最佳生产模式,使农户获得最高的经济效益,来降低冷害带来的风险.     

最优化技术在确定最佳施肥量提高农产品品质上的应用

农产品的品质,无论是加工品质和贮藏品质,还是食用品质,作为一个综合概念,均与一系列的品质性状有关。要想通过合理施肥,既使产品的质量满足消费者特别是加工和销售部门对产品品质的特殊需求,又能获得最大的经济效益,将涉及到在复杂的农业生物系统中综合目标的实现。本研究应用优化控制的方法,在微机上建立了非线性数学优化模型。优化计算的实例显示,利用优化模型可以迅速方便地计算出既能达到所要求的农产品品质指标,又能获得最大经济效益的最佳NPK施肥量。与其他方法相比较,由于优化模型一方面考虑到了NPK三种主要营养元素对作物生长的复合作用;另一方面,应用了多项产量和品质参数来衡量作物的肥效反应,因而较现行确定施肥量的方法有更大的可靠性。此外,利用这一优化模型既可以评价作物的肥效效应,又可以确定获得期望达到的生长效应所需要的NPK施肥量,故较目前常见的模拟模型有更多的功用。     

新疆塔里木盆地盐碱土综合治理与水资源合理分配规划模型研究

本文对新疆塔里木盆地盐碱土综合治理和水资源合理分配问题进行了研究,并提出了一个多层次数学模型。该模型在考虑盆地内各灌区经济目标、社会目标和生态目标以及资源、环境、资金等限制因素的基础上,对各灌区的土壤改良和水资源分配进行了系统优化,提出了多种可供选择的替代方案,并通过对这些方案预期效果的综合评价,选择在全盆地范围内最满意的方案。最后,对模型计算的结果结合实际进行了初步分析和评价。     

土地资源配置的可拓目标规划模型及其应用初探

从不同角度生成各种决策方案,可为土地资源优化配置提供充分的信息和备选方案,也是实现土地资源优化配置的基础,但目前对如何生成决策方案这一问题却研究得较少。该文通过可拓工程与目标规划模型相结合,建立了从不同角度生成各种方案的可拓目标规划模型方法,并以山西省隰县试区为例,探讨了可拓目标规划模型的应用及其方案生成的方法。结果表明：土地资源配置的可拓目标规划模型及其规划方案生成的方法,可通过变换规划目标、约束条件、决策变量等途径来实现,该方法是从不同角度生成各种土地资源配置方案的较好方法。     

车辆主动悬架路面自适应控制系统

针对不同的路面状况,采用增加高低通非线性滤波器的方法,对控制目标进行优化处理,并利用逆向递推(Backstepping)技术,设计了一种主动悬架的路面自适应控制器。仿真结果表明,在不同的路面激励信号作用下,都能取得较好的控制效果,与被动悬架相比,大大改善了乘座的舒适性。     

A decision support system for soil and water conservation measures on agricultural watersheds

Integrated watershed management (IWM) is vital in achieving agricultural sustainability in terms of both production and environmental protection. A decision support system (DSS) is useful in generating alternative decision scenarios for management of natural resources, facilitating the implementation of IWM concepts in an interactive and holistic way. The decision to implement an appropriate land use coupled with suitable soil and water conservation techniques not only enhances watershed health but also prevents sediment losses. Besides reducing basin fertility, such losses decrease the storage capacity of downstream reservoirs through silt deposition, which can, in turn, give rise to low biomass production and poorer flood control. In order to facilitate IWM, an effort was made to develop, in the Visual Basic programming language, a soil and water conservation DSS which considered both structural and cropping practices for arresting sediment loss. Input parameters to the DSS for a given tract of land included: mean slope; sediment loss; soil type; and land capability class (LCC). Outputs included decision criteria to choose among alternative structural measures and suggested cropping systems to serve as biological measures to reduce soil loss and conserve water. Structural watershed management measures included a variety of soil and water conservation structures widely adopted by farming communities throughout the world. The DSS is capable of providing sediment control solutions not only for small watersheds but also for larger drainage basins, by dividing the basin into smaller watersheds. The DSS was validated for a watershed on the Caribbean island of St Lucia and used to suggest measures for a 10° slope under specific soil type, sediment loss and LCC conditions. The measures proposed included bench terraces, graded contour bunds, conservation ditches, concrete chute spillways, diversion dams and conservation cropping systems. The measures actually adopted on‐site were conservation ditches, graded contour bunds and conservation cropping systems, a close parallel to the DSS's proposed measures. On slopes ranging from 5–55°, implementation of the suggested control measures resulted in a 34–37 per cent reduction in soil loss on the watershed. Copyright © 2004 John Wiley & Sons, Ltd.     

Feeding corn distillers grains as an energy source to gestating and lactating beef heifers: Impact of excess protein on feedlot performance,glucose tolerance,carcass characteristics and Longissimus muscle fatty acid profile of steer progeny

This study was conducted to determine the impact of dried distiller's grain with solubles (DDGS) from 192 days of gestation through 118 days of lactation on feedlot performance, carcass characteristics, Longissimus muscle (LM) fatty acids and glucose tolerance of male progeny (n = 36). Angus‐Simmental heifer dams were fed diets that contained either DDGS (DG) or not (CON) formulated to provide similar daily net energy for gain but differing crude protein. In the feedlot, male progeny were fed a diet devoid of DDGS. An intravenous glucose tolerance test (IVGTT) was performed on a subset of 20 steers prior to harvest. Steers were harvested at a common 12th rib fat depth. Data were analyzed with the GLIMMIX and MIXED procedures of SAS. Performance (P ≥ 0.11) and glucose and insulin concentrations during IVGTT (P ≥ 0.24) did not differ between treatments. Dressing percentage tended to be greater (P = 0.09) in DG than CON progeny, but all other carcass characteristics did not differ (P ≥ 0.18). Progeny from DG dams had greater LM 16:2, 18:0, and 20:1 n‐9 concentrations than progeny from CON dams (P ≤ 0.02). In conclusion, DDGS are a viable option for gestating and lactating beef cows.     

混合整数可行性问题的一个求解方法

给出了混合整数可行性问题的一个求解方法。首先把混合整数可行性问题转化为线性互补问题,其次给出了求解一般线性互补问题的混合整数线性规划解法,最后给出算例来说明该方法的可行性和有效性。     

永丰草地畜牧业生产系统分析

运用线性规划模型，对甘肃省天祝藏自治县永丰草地的畜牧业生产进行了系统分析。结果表明在保持现有牦牛、绵羊头数（年１８０６７头、羊２６９１２只，总载畜量１１７２４７羊单位）和人工草地（１３３ｈｍ＾２）时，仅调整畜群结构，可使纯收益增加２０％。