非负矩阵谱半径的上界估计

非负矩阵的谱半径估计是非负矩阵理论研究的重要课题之一.如果谱半径的上界能够表示为非负矩阵元素的易于计算的函数,那么这种估计价值更高.结合非负矩阵的迹分两种情况给出非负矩阵谱半径的上界序列,并且给出数值例子加以说明.     

非负不可约矩阵Perron根的上界

非负矩阵在数学物理、控制论、电力系统理论等领域有广泛的应用.非负矩阵Perron根的估计是矩阵分析理论研究中的重要问题.利用M-矩阵与非负矩阵之间的关系,给出计算非负不可约矩阵Perron根上界的一种新算法,数值例子表明该算法具有可行性.     

非负矩阵最大特征值的新界值

非负矩阵最大特征值的估计是非负矩阵理论中重要的课题,如果上下界能表示为收敛的序列,则能得到最大特征值更精确的估计。借助2个新的矩阵给出了非负矩阵最大特征值的一种新的估计方法,得到非负矩阵最大特征值范围的界,并通过实例说明了估计的有效性和精确性。     

非负矩阵最大特征值的新界值

非负矩阵最大特征值的估计是非负矩阵理论研究的重要组成部分.如果上下界能够表示为非负矩阵元素的易于计算的函数,那么这种估计价值更高.本文通过构造两个收敛的序列得到非负矩阵最大特征值的新界值.数值算例表明其结果比有关结论更加精确.     

矩阵负指数多项式的计算方法

本文介绍了利用矩阵最小多项式计算负指数矩阵多项式的具体方法。     

关于灰色非负矩阵的Perron—Frobenius定理及其证明

本文给出了有关灰色非负矩阵的几个定义,并利用紧凸集的性质和拓扑映射的Brouwer不动点定理证明了关于灰色非负矩阵的Perron-Frobenius定理,为灰矩阵在社会、经济、科技等大系统研究中的深入应用奠立了一定的基础。     

非负矩阵Hadamard积谱半径上界的不等式

非负矩阵的Hadamard积是矩阵分析理论研究中的重要问题.在H9lder不等式的基础上,利用相似矩阵具有相同特征值这一特点给出两个n阶非负矩阵A和B的Hadamard积AB谱半径的上界,所得结果只依赖于两个非负矩阵的元素,便于计算.数值例子表明新估计式在一定条件下改进了现有的一些结果.     

基于正交非负矩阵分解的高光谱遥感图像混合像元分解

像元分解是遥感图像信息挖掘的重要手段,非负矩阵分解模型应用于高光谱遥感图像混合像元分解时,分解的效果与算法所获局部最优解密切相关。本文将带正交性约束的非负矩阵分解用于光谱解混,保证了分解矩阵列向量的线性无关性,进而使分解所得端元光谱具有较大的独立性。通过试验分析,利用正交非负矩阵分解,实现了对1997年机载可见光及红外成像光谱仪(AVIRIS)高光谱图像的混合像元分解,结果表明,增加约束条件后的正交非负矩阵分解,能成功分离出6种端元光谱,解混出的端元光谱与参考光谱的光谱角距离更小,与真实地物的丰度谱图吻合度增强。     

混浊介质后向散射的Mueller矩阵的偏振特性分析

对典型混浊介质（Intralipid悬浊液）后向散射的Mueller矩阵进行了试验测量。基于Mueller矩阵计算的保偏度反映散射介质某点的偏振效应：接近光入射点的区域,保偏能力较强;随着距离的增加,保偏能力逐渐减弱而趋向于1;混浊介质浓度加大,将导致介质的保偏能力减弱。     

非负矩阵谱半径的新界值

非负矩阵谱半径的估计是非负矩阵理论中重要的课题。对Frobenius界值方法加以研究,给出了一种易于计算且能得到较紧的界的方法,并通过数值算例与以往的结果进行比较,有一定的精确性。     

一类偏序线性代数上的Freudenthal谱定理

利用一类特殊的偏序线性代数上的极大投影的概念,讨论了其上的Freudenthal谱定理,不同于以往的方法,仅仅使用了偏序和Dedekindσ完备的基本概念.最后,给出了一个偏序线性代数的例子,它不是格,但是Freudenthal谱定理依然成立.     

部分预应力T梁试验研究

介绍了新兴立交桥部分预应力Ｔ梁检算、静载试验过程和试验结果。通过理论及试验结果表明，该部分预应力Ｔ梁强度及刚度均满足设计和使用功能要求。本文还特别对普通钢筋的配筋量进行了讨论。     

莲雾化肥减施增效技术应用效果研究

为发展生态循环农业,推进农业绿色先行先试支撑体系建设,开展莲雾化肥减施增效技术应用试验,在每亩化肥使用量减少5%以上的基础上实现莲雾化肥减施增效。本研究以三亚南鹿农庄莲雾为试材,常规种植管理为对照,设置了有机无机复合专用肥部分替代化肥、专用型莲雾炭基肥部分替代化肥、有机肥部分替代化肥、生物有机肥部分替代化肥以及全程智能水肥一体化试验区,并观测莲雾产量、肥耗、单果重、SPAD值、优等果率以及果实品质。结果表明,化肥减施条件下,与常规施肥处理相比,所有减肥处理均能提高莲雾单果重以及莲雾产量,其中在化肥减少17%的条件下,生物有机肥部分替代化肥处理的产量提高了31.8%,单果重提高了8.7%,可溶性固形物提高了57%,肥耗降低了37.1%,其化肥减施增效效果最好。     

Reduction of naturally occurring motoneuron death in vivo by a target-derived neurotrophic factor

Treatment of chick embryos in ovo with crude and partially purified extracts from embryonic hindlimbs (days 8 to 9) during the normal cell death period (days 5 to 10) rescues a significant number of motoneurons from degeneration. The survival activity of partially purified extract was dose-dependent and developmentally regulated. The survival of sensory, sympathetic, parasympathetic, and a population of cholinergic sympathetic preganglionic neurons was unaffected by treatment with hindlimb extract. The massive motoneuron death that occurs after early target (hindlimb) removal was partially ameliorated by daily treatment with the hindlimb extract. These results indicate that a target-derived neurotrophic factor is involved in the regulation of motoneuron survival in vivo.     

隐马尔可夫模型下基于SIFT特征的局部遮挡目标识别

提出一种利用隐马尔可夫模型建立目标特征匹配库来识别图像中局部遮挡目标的新方法。该方法首先通过SIFT算法提取目标SIFT特征,然后采用隐马尔可夫模型对目标所有的SIFT特征进行训练,得到目标SIFT特征对应的模型输出概率范围,将该概率范围作为目标特征匹配库。在对图像中的目标进行识别时,利用目标特征匹配库可以把目标特征从图像所有特征中识别出来,即使目标遮挡比例为60%时,该方法仍能识别出目标。实验结果表明,新方法可以精准地识别出图像中被遮挡目标,能够很好地解决遮挡情况下的目标识别问题。与现有局部遮挡目标识别算法相比,新方法所取得的目标识别率均有所提高。     

Antagonistic relationship between dietary cadmium and zinc

The growth of chicks decreased, and specific abnormalities of hocks and feathers increased, when cadmium was added to a zinc-deficient diet. Supplementation of the diet with zinc prevented the adverse effect of cadmium on hock and feather development and partially offset the effect on growth. Changes in the gizzard lining, also resulting from cadmium ingestion, were partially prevented by increase in the zinc intake.     

Partially Molten Middle Crust Beneath Southern Tibet: Synthesis of Project INDEPTH Results

INDEPTH geophysical and geological observations imply that a partially molten midcrustal layer exists beneath southern Tibet. This partially molten layer has been produced by crustal thickening and behaves as a fluid on the time scale of Himalayan deformation. It is confined on the south by the structurally imbricated Indian crust underlying the Tethyan and High Himalaya and is underlain, apparently, by a stiff Indian mantle lid. The results suggest that during Neogene time the underthrusting Indian crust has acted as a plunger, displacing the molten middle crust to the north while at the same time contributing to this layer by melting and ductile flow. Viewed broadly, the Neogene evolution of the Himalaya is essentially a record of the southward extrusion of the partially molten middle crust underlying southern Tibet.     

Drilling on midway atoll, hawaii

Two holes drilled through reef sediments into basalt have established a geologic section through the Miocene. Midway was built above the sea by flows that were weathered and partially truncated in pre-Miocene time. After submergence, volcanic clays were reworked and covered by limestones. Overall ubmergence was interrupted at least twice by emergence. The limestones have been leached, recrystallized, and partially dolomitized.     

Partial Synchronization of Nuclear Divisions in Root Meristems with 5-Aminouracil

Root tip cells of Vicia faba were partially synchronized in nuclear stages by treatment for 24 hours with 700 parts of 5-aminouracil per million. All division was suppressed by the analog treatment, and a peak in division stages ( up to 62.5 percent) was reached 14 hours after removal from the aminouracil. Populations of partially synchronized cells can be useful in experiments designed to study various intracellular reactions or responses at different stages in the nuclear cycle.     

改变蛋壳通透性对肉鸡种蛋失水率及出雏影响的研究

在肉鸡种蛋孵化的０ｄ、５．５ｄ、１０．５ｄ和１５．５ｄ用稀盐水洗蛋和用明胶封闭部分蛋壳,研究其对种蛋失水率及出雏的影响。结果表明：用稀盐水清洗种蛋增加蛋壳通透性不能显著提高种蛋失水率,胚胎自身具有渗透压调节作用,但对提高受精蛋孵化率有利;对出雏重、出雏重占入孵蛋重比率及孵化时间没有影响。用明胶封闭部分蛋壳降低蛋壳通透性,显著降低了失水率,影响胚胎气体交换,导致受精蛋孵化率较低,出雏重增大（ｐ＞０．０５）。