蜕化p-Laplace方程无穷多解的存在性

研究了一类在无穷远处具超线性条件的蜕化p-Laplace方程无穷多解的存在性.由于没有假设A-R条件,不能像通常那样得到(PS)c条件,为此证明其满足Cerami条件,再利用对称山路引理,得到了无穷多解的存在性.     

具有次二次位势的二阶哈密尔顿系统的周期解的存在性

利用变分法研究二阶哈密尔顿系统的周期解.减弱了以前的次二次条件并得到解的存在性.     

质点系对任意点的动量矩定理及其应用

本文详细推导了质点系对于任意点的动量矩定理，该定理具有普遍性，由它可以导出质点系对于定点、质心、刚体作平面运动时速度瞬心的动量矩定理。运用这些定理可以很方便地求解某些问题。     

枯草杆菌重组水蛭素的冷冻干燥工艺及热稳定性研究

[目的]研究枯草杆菌重组水蛭素的冷冻干燥优化工艺及在酸碱中的热稳定性。[方法]测定不同填充剂、保护剂浓度组合下的共熔点，根据共熔点最高的原则确定其组合浓度，据此再设计水蛭素的冷冻干燥工艺。[结果]优化的冷冻干燥工艺为：填充剂浓度4％，保护剂浓度1．2％，共熔点为-30℃，装样量为3．0ml，冷冻温度-40℃，冷冻时间2h，升华干燥温度-32℃，升华时间24h，再干燥温度25℃，时间5h，活力回收为96．2％，含水量为1．48％。100℃时，酸性条件下，水蛭素非常稳定；加热结合碱性的条件下水蛭素才相当不稳定。[结论]可为进一步工业化冷冻干燥水蛭素研究提供借鉴。     

Tomato yield, biomass accumulation, root distribution and irrigation water use efficiency on a sandy soil, as affected by nitrogen rate and irrigation scheduling

Florida is the largest producer of fresh-market tomatoes in the United States. Production areas are typically intensively managed with high inputs of fertilizer and irrigation. The objectives of this 3-year field study were to evaluate the interaction between N-fertilizer rates and irrigation scheduling on yield, irrigation water use efficiency (iWUE) and root distribution of tomato cultivated in a plastic mulched/drip irrigated production systems. Experimental treatments included three irrigation scheduling regimes and three N-rates (176, 220 and 230 kg ha⁻¹). Irrigation treatments included were: (1) SUR (surface drip irrigation) both irrigation and fertigation line placed right underneath the plastic mulch; (2) SDI (subsurface drip irrigation) where the irrigation line was placed 0.15 m below the fertigation line which was located on top of the bed; and (3) TIME (conventional control) with irrigation and fertigation lines placed as in SUR and irrigation being applied once a day. Except for the “TIME” treatment all irrigation treatments were controlled by soil moisture sensor (SMS)-based irrigation set at 10% volumetric water content which was allotted five irrigation windows daily and bypassed events if the soil water content exceeded the established threshold. Average marketable fruit yields were 28, 56 and 79 Mg ha⁻¹ for years 1-3, respectively. The SUR treatment required 15-51% less irrigation water when compared to TIME treatments, while the reductions in irrigation water use for SDI were 7-29%. Tomato yield was 11-80% higher for the SUR and SDI treatments than TIME where as N-rate did not affect yield. Root concentration was greatest in the vicinity of the irrigation and fertigation drip lines for all irrigation treatments. At the beginning of reproductive phase about 70-75% of the total root length density (RLD) was concentrated in the 0-15 cm soil layer while 15-20% of the roots were found in the 15-30 cm layer. Corresponding RLD distribution values during the reproductive phase were 68% and 22%, respectively. Root distribution in the soil profile thus appears to be mainly driven by development stage, soil moisture and nutrient availability. It is concluded that use of SDI and SMS-based systems consistently increased tomato yields while greatly improving irrigation water use efficiency and thereby reduced both irrigation water use and potential N leaching.     

数字化地籍测量中定向错误的类型与改正方法

数字化地籍测量中,利用控制点进行定向操作时容易出现错误。如果定向出现问题,将导致该站所测的界址点均出现错误。本文根据不同的错误类型,推导出了不同的数学模型。有些定向错误可以通过数学模型修正,有的错误类型则无法修正,当尽量避免。     

数字化人体模型在车身逆向布置中的应用

以人体参数为依据建立的数字化人体模型能有效的描述人体的形态特性.本文在CATIA人机工程模块中,建立了人群文件,生成自定义的三维数字化人体模型。在此基础上建立了满足不同百分位需求的参数化人体模型。以某汽车为对象,根据SAE标准,综合考虑了踏板行程、汽车视野和上下肢舒适性等因素对驾驶员的影响,最终得到满足各种约束的驾驶员最佳舒适性H点区域。论文研究为针对不同地区人群特性对车型进行逆向开发和逆向布置提供了很好的参考。     

遗传算法及其在渔饲料配方中的应用

首先阐述了参数编码、初始群体、适应度函数、遗传操作以及算法控制参数等遗传算法基本原理,然后着重介绍其在渔饲料配方中的应用,在该应用中采用了实数编码、基于线性排名的选择、算术杂交和非一致变异等遗传算法方法。结果表明,在渔饲料配方优化中应用遗传算法要优于目前饲料配方软件中大多采用的常规应用数学的优化方法。主要体现在单位产量饲料配方中的成本价格前者要低于后者。由于遗传算法能够解决因子较多,非线性程度高的问题,从而得出的饲料配方能更好的符合相关鱼种的营养含量标准。     

The significance of meandering channel morphology on the diversity and abundance of macroinvertebrates in a lowland river in Japan

• 1. Many rivers and streams across the world have been channelized for various purposes. Channel cross‐sections of meandering rivers are asymmetrical and have cross‐sectional diversity in their physical environment; cross‐sections of a channelized river are typically trapezoidal and have little cross‐sectional diversity, both in physical and ecological conditions. Several programmes to restore stream meanders have been undertaken to improve river ecosystems degraded by channelization. However, the association between diversification in the physical environment due to meander restoration and the macroinvertebrate community structure is poorly known.
• 2. This study of a lowland river in Japan assessed how the cross‐sectional diversity of the physical environment changed with restoration of a meander in a channelized river, and how the macroinvertebrate communities responded to the changes in physical habitat variation. Comparisons were made between the macroinvertebrate communities of a channelized reach, the restored meandering reach, and a natural meandering reach.
• 3. Natural meandering and restored meandering reaches showed higher cross‐sectional diversity in physical variables and total taxon richness across a reach than did the channelized reach. Almost all taxa observed in the natural and restored meandering reaches were concentrated in the shallowest marginal habitats near the banks. Shear velocity increasing with water depth had a negative association with macroinvertebrate density and richness.
• 4. This study demonstrated that the shallow river bed along the inside of bends formed point bars that provided a highly stable substrate, a suitable habitat for macroinvertebrates in a lowland river. It is concluded that meander restoration could be an effective strategy for in‐stream habitat restoration in lowland meandering rivers.

Copyright © 2007 John Wiley & Sons, Ltd.     

基于核心主导人物构建团队的拓扑形态分析

以核心主导人物构建团队的方式,运用点集拓扑学中凝聚点的概念,将核心主导人物看作团队的凝聚点,得到核心主导人物集合是团队拓扑空间的闭集,并由此对由3个成员的团队进行分析,得出了同胚意义下的所有拓扑形态。