一种多基元类的布局迁移自适应算法及在闸机设计中的应用

布局问题研究物体的布局先后或布局定位以满足设计要求,布局迁移设计是在已有布局基础上高效设计新布局的方法。在轨道交通自动控制系统中,闸机表面传感器的布局对人与物的识别有重要的影响。为了实现闸机在不同地域环境中的快速设计,首先以闸机布局中的传感器作为研究对象,进行基元划分,提出了多种基元类型;并分析了基于拓扑结构的基元迁移变换方法,研究了人群特征因素、机械结构约束的数学表达;然后提出基于包围圆搜索的基元运动与干涉分析算法,其参数能够根据求解精度进行自适应调整;并利用多目标归一化函数对各基元的解进行择优,以获取最终布局。最后以18对传感器的闸机布局设计为例进行实例分析,应用此方法并借助于Visual Basic可视化编译平台,实现了闸机在不同地域环境中的传感器布局快速设计。     

Root growth and phosphorus and potassium uptake by two corn genotypes in the field

In a field study P and K uptake by two corn (Zea mays L.) genotypes which differed in root growth was investigated. The effect of differences in root growth on P and K uptake was assessed using a mechanistic-mathematical model which describes nutrient uptake by growing plant roots in soil. Nitrogen was applied at 0 and 227 kg ha^–1 to Pioneer 3732 and B73xMo17 corn grown on Raub silt loam (fine-silty, mixed, mesic Aquic Argiudoll) and at 227 kg N ha^–1 to these two genotypes on Chalmers silt loam (finesilty, mixed, mesic, Typic Haplaquoll). Root growth and P and K uptake by the two corn genotypes was measured 31, 47, 75 and 91 d after planting on the Raub and 31, 47, 61 and 75 d after planting on the Chalmers soil.Root growth and P and K uptake by B73xMo17 was greater than that of Pioneer 3732 on N-fertilized Raub soil. On Chalmers soil the difference in root growth between the two genotypes resulted in an increase in K but not P uptake. The higher soil P level of the Chalmers appears to have offset possible differences in P uptake due to root size. There were no differences between the two genotypes in either the percentage of roots with root hairs, or the density or length of root hairs. Phosphorus and K uptake calculated with the simulation models for both corn genotypes on both soils over each of three growth periods agreed with observed P (Y = 0.68X + 1.71; r = 0.944^**) and K (Y = 0.88X + 15.52; r = 0.928^**) uptake. Differences in P and K uptake between B73xMo17 and Pioneer 3732 resulted primarily from the difference in root growth in the topsoil. A high correlation was found between root surface area and P (r = 0.893^**) and K (r = 0.928^**) uptake by both corn genotypes on both the soils.Journal paper No. 10,316 Purdue Univ. Agric. Exp. Stn., W. Lafayette, In 47906. Contribution from the Dep. of Agron. This paper was supported in part by a grant from the Tennessee Valley Authority.     

Inhibition and recovery of cucumber roots given multiple treatments of ferulic acid in nutrient culture

Ferulic acid, a frequently cited allelopathic agent, inhibited photosynthesis, leaf expansion, and root elongation of cucumber seedlings grown in aerated nutrient cultures in a growth chamber. Other effects were a reduction in the proportion of radioactivity fixed by photosynthesis translocated to roots, a stimulation in secondary root initiation, and an increase in root-shoot ratios. Inhibition of leaf expansion and root elongation induced by multiple ferulic acid treatments was rapidly lost once ferulic acid was removed from the root environment. The changes in general root morphology, i.e., average root length and root number, associated with ferulic acid treatments, were partially reversed or not affected when ferulic acid was removed from the root environment.Paper No. 11411 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, North Carolina 27695-7601. The use of trade names in this publication does not imply endorsement by the North Carolina Agricultural Research Service of the products named, nor criticism of similar ones not mentioned.     

多机系统处理机调度算法的设计与实现

本文论述的是用IBMPC及其兼容机作为节点机组成的总线型紧耦合的多机系统中的处理机调度算法的设计与实现。作者根据各节点机具有独立工作能力主动性和智能性,设计并实现了一种适合本系统的面向实现的分布/集中式调度算法。分布在这里是指算法的局部算法是分布在各处理机上;集中在这里是指全局共享的控制数据是集中存放在共享存贮器中。用于实现调度的原语全部用C语言可调用的函数形式给出。     

Anticipating Degradation in State Estimation Accuracy via Online Nonlinear Observability Analysis

A methodology is proposed to enable real-time evaluation of the observability of local motions, and generate a local observability cost map to enable informed local motion planning in order to avoid potential degradation or degeneracy in state estimator performance. The proposed approach leverages efficient numerical techniques in nonlinear observability analysis and motion primitive-based planning technique to realize the local observability prediction with real-time performance. The degradation of the state estimation performance can be readily predicted with the local observability evaluation result. The proposed approach is specialized to a representative optimization-based monocular visual-inertial state estimation formulation and evaluated through simulation and experiments. The experimental results demonstrated the ability of the proposed methodology to correctly anticipate the potential state estimation degradation.     

基于通用智能卡的可信引导方案

为了解决传统的操作系统引导机制存在关键验证信息被绕过的风险和引导数据被篡改的安全隐患,基于可信计算理论,结合带光盘文件系统的智能卡技术,提出了基于通用智能卡的可信引导方案.在不改变智能卡和终端设备的硬件和固件结构的基础上,通过改造智能卡的存储数据和磁盘的引导数据,实现用户身份信息、智能卡和终端设备绑定的安全目标,将可信计算机制从开机加电扩展至应用层,确保操作系统的初始状态可信.通过安全性分析和性能分析,证明终端设备引导的安全性,并且在实际应用中得到了验证.     

基于前掠式HWB(翼身融合混合布局)无人飞行器的初步研究

根据前掠翼布局及飞翼布局的特点,针对前掠式HWB(翼身融合混合布局)建立模型,采用流场可视化分析方法,对前掠式HWB(翼身融合混合布局)模型进行流场分析,发现在较合理的气动布局设计情况下可以有效的改善前掠翼气动弹性发散、翼根失速等问题从而获得良好的气动性能.在此基础上进一步试制模型并试飞,获得了较为理想的效果.为前掠翼飞机的实用化做了前期的探索.     

施磷方式对蓖麻生长和铅积累的影响

采用盆栽实验研究了土壤重金属铅污染下（1 000mg·kg-1）,磷肥根施和根施配合叶面喷施两种方式对能源作物蓖麻生长和铅积累特征的影响。结果表明,根施磷肥对蓖麻形态和生物量影响很小,而根施配合叶面喷施显著地提高了蓖麻总生物量。根施磷肥降低了蓖麻地下部对铅的富集,根施配合叶面喷施则大幅度提高了蓖麻叶片对铅的积累量,从而提高了蓖麻地上部的铅积累量,两者与对照相比分别提高了90.01%和79.40%。磷肥根施配合叶面喷施对蓖麻铅富集系数影响很小,但大大提高了转运系数,达0.549,是对照的1.91倍。因此,适当的磷肥根施配合叶面喷施可以有效提高蓖麻铅从根系到地上部的转移能力,从而提高蓖麻对土壤铅的萃取能力和修复效果。     

二元生成自由群的幂单性质(英文)

为了研究二元生成自由群的幂单性质,依据组合群理论,讨论了本原元素的若干组合方式,证明了可用于处理幂零的几组新方程.证明了可以嵌入一般线性群的二元生成自由群是幂单群的充要条件是它的每个本原元素均是幂单的.     

连云港市金融中介支持科技企业研究

研究企业科技创新的金融支持问题,对于促进企业科技创新能力的发展,实现建立创新型国家的目标,促进经济结构转型具有极为重要的意义。选取连云港市2002—2012年间科技创新与金融支持的相关数据进行实证分析,通过单位根检验、协整分析与格兰杰因果检验得到以下结论:金融规模与科技创新长期正相关,金融效率与科技创新负相关。并在此基础上,提出了促进连云港市科技创新金融支持的意见与建议。