一种确保压缩空气在线性长度上均匀性的方法

简要分析了造成压缩空气在线性长度上分布不均匀的若干原因 。

一种基于非线性长度的多约束路由算法

满足多个约束的QoS路由问题已经被证明是NP完全问题。在分析了多种路由算法的基础上,设计了一种高效的多约束路由算法。该算法采用非线性路径长度计算方法。为提高算法的成功率,在节点的松弛过程中设计了节点动态路径长度计算,允许节点作多次松弛。为提高算法的执行效率,在节点正向松弛和反向估计过程中引入了受控路径的思想,使算法得到了优化。大量仿真表明,该算法在最短路径获取和路由发现成功率方面都有高效的表现。

一种基于蚁群算法和非线性长度的多约束路由算法

在分析了多种路由算法的基础上,设计了一种基于蚁群算法的多约束路由算法。该算法采用了非线性路径长度,通过蚂蚁的周游获得长度更短的多约束路径。仿真表明,该算法在最短路径获取和路由发现成功率方面都有高效的表现。

有限域上定长序列的最短线性递归长度分布

研究有限域F(q)上任意给定长度的序列的最短线性递归长度的分布.对任意正整数n和0 l n,计算出了长度为n、最短线性递归长度为l的序列个数,指出了对于固定长度为n的任意序列,其最短线性递归长度大部分情况下等于n/2或n/2+1,即其最短线性递归长度的分布一般都集中在长度的一半位置.

分压器的特性研究

本文对滑线式变阻器作分压器时的输出电压与其输出电阻线性长度的关系进行了讨论。

光参量啁啾脉冲放大系统非线性晶体长度确定及调谐方法研究

首先介绍了模拟光参量啁啾脉冲放大(OPCPA)过程的多种计算模型,在此基础上提出了三步走逐步逼近算法,以确定OPCPA过程中最稳输出时所需的非线性晶体长度.这种算法综合利用了上述计算模型,随着计算模型越来越精确,非线性晶体长度的计算范围越来越小.因而利用这种算法能高效、精确地确定最佳非线性晶体长度.最后提出在OPCPA过程引入一定的相位失配量,来调谐最稳输出时所需晶体长度,从而能突破晶体加工精度不够的局限,在实际OPCPA过程中获得稳定输出.

青少年足长与身长关系的研究

足长与身长的关系国内外学者研究较少,为弄清其关系,为人类学、法医学积累资料。我们按照活体测量要求(黄新美,1983),于1983年对鄂西7—17岁1533名(男863人,女670人)青少年的足长(pte—ap)和身长进行了测量。并将每人测量的原始数据,按性别、年龄输入AppleⅡ电子计算机,对数据进行分析处理。计算语言为BASIC语言,主要采用直线回归程序,以分析青少年足长与身长的线性长度关系。现将结果报告如下。

最小共享干扰——负荷平衡QoS路由算法

文中将链路共享、负荷均衡性以非线性路径长度的统一形式纳入QoS寻径决策中 ,并以“最短路径优先”为准则 ,提出一种QoS路由算法 ,该算法能选择合适路径、能调节链路共享、能平衡网络负荷 。

Berlekamp-Massey算法的新描述形式

流密码在密码学中是非常重要的一种加密体制,而其主要思想是采用伪随机序列进行加密。在生成流密码所需的伪随机序列过程中,发现该伪随机序列的最短线性递归长度的分布具有一定的规律,为了对这些规律进行深入的理论分析,提出了对求解其最短线性递归长度的Berlekamp-Massey(BM)算法的另一种描述形式。使用这种形式进行描述可以简化原有BM算法的描述及程序实现,对于进一步从理论上研讨分析最短线性递归长度的分布规律有很大的帮助,从而可以对生成流密码所需的序列有更深入的了解,能够生成更适用的伪随机序列。

Vegetation Growth Monitoring Under Coal Exploitation Stress by Remote Sensing in the Bulianta Coal Mining Area

Coal exploitation inevitably damages the natural ecological environment through large scale underground exploitation which exhausts the surrounding areas and is the cause of surface subsidence and cracks. These types of damage seriously lower the underground water table. Deterioration of the environment has certainly an impact on and limits growth of vegetation,which is a very important indicator of a healthy ecological system. Dynamically monitoring vegetation growth under coal exploitation stress by remote sensing technology provides advantages such as large scale coverage,high accuracy and abundant information. A scatter plot was built by a TM (Thematic Mapper) infrared and red bands. A detailed analysis of the distributional characteristics of vegetation pixels has been carried out. Results show that vegetation pixels are affected by soil background pixels,while the distribution of soil pixels presents a linear pattern. Soil line equations were obtained mainly by linear regression. A new band,reflecting vegetation growth,has been obtained based on the elimination of the soil background. A grading of vegetation images was extracted by means of a density slice method. Our analysis indicates that before the exploitation of the Bulianta coal mining area,vegetation growth had gradually reduced; especially intermediate growth vegetation had been transformed into low vegetation. It may have been caused by the deterioration of the brittle environment in the western part of the mining area. All the same,after the start of coal production,vegetation growth has gradually improved,probably due to large scale aerial seeding. Remote sensing interpretation results proved to be consistent with the actual situation on the ground. From our research results we can not conclude that coal exploitation stress has no impact on the growth of vegetation. More de-tailed research on vegetation growth needs to be analyzed.

Screening efficiency and screen length of a linear vibrating screen using DEM 3D simulation

The effect of screen length on the screening efficiency of particles is studied under various single parameter conditions including frequency, amplitude, vibration angle, and screen inclination. The Discrete Element Method (DEM) has been used to simulate the screening process. A functional relationship between screening efficiency and screen length is established. It is shown that screening efficiency and screen length have a complicated exponential relationship. Relationships between them are profoundly discussed and conclusions are easily drawn: low values of the parameters do not benefit screening; screening efficiency generally increases with screen length; screening efficiency reaches a plateau when these parameters are in range frequently encountered in practical applications.

Maternal Inheritance of Yellowfin Tuna （Thunnus albacares） in Captivity

Mitochondrial DNA introgression has been suggested to be responsible for the maternal consistent implications. Study on mt-DNA （mitochondrial DNA） variation in the yellowfin tuna （Thunnus albacares） using RFLP （restriction fragment length polymorphisms） has provided the evidence of maternal inheritance of yellowfin tuna in captivity. Eggs were collected in every spawning in 2004-2006 season. The mt-DNA genotypes of broodstock were compared with their eggs and the maternal inheritance of these females was determined from genotypes in the eggs. The result showed that six genotypes of female broodstock were observed in eggs and four of them were found to share a single female＇s identity and one type was shared by two females. The same genotype was observed in almost every sampling throughout the year. The female broodstocks spawned almost daily throughout the season.

AFLP analysis of genetic variation among three natural populations of horseshoe crab Tachypleus tridentatus along Chinese coast

The AFLP(amplified fragment length polymorphism) technique was used to analyze and compare the genetic diversity of Tachypleus tridentatus from three south-eastern coastal sites of China(Pingtan,Hong Kong and Beihai).Eight pairs of primers generated 361 loci,including 285 polymorphic loci.The ratio of polymorphic loci was 96.97%.Nei's genetic diversity index was 0.420 8 and the Shannon information index was 0.607 5,both of which were higher than that reported for many other arthropods.These results show that the genetic diversity detected was mainly caused by individual differences within a population.Genetic distance showed that the rational division of the three geographic populations of T.tridentatus along the south-eastern coast of China was not significant,in which the genetic distance was not proportional to the geographic distance.All three horseshoe crab populations may belong to a large group,and had a high degree of genetic similarity.The high level of genetic diversity obtained from the present AFLP analysis may be due to the large effective population size of the species in Chinese waters.

The Stability Study of Globe Transportation Center of Beijing Capital International Airport

The stability of long span steel arch structure of globe transportation center (GTC) in the Beijing Capital International Airport was studied. Different objective models such as single arch model, composite arch model and global structural model were introduced to analyze the structural stability by means of the finite element technique. The eigen buckling factor of the steel arch structure was analyzed. The geometrical nonlinearity, elastic-plastic nonlinearity and initial imperfection were taken into account in the investigation of the structural buckling, and the nonlinearity reduction factors for the steel arch structure were discussed. The effects of geometrical nonlinearity and initial imperfection on the structural buckling are light while the effect of material nonlinearity is quite remarkable. For a single steel arch, the dominant buckling mode occurs in out-of-plane of arch structure. The out-of-plane buckling factor of the composite steel arch is greater than that of the single steel arch while the in-plane buckling factor of the former is somewhat less than that of the latter. Moreover, the webs near the steel arch feet have the lowest local buckling level and the local buckling is more serious than the global buckling for the global structure.

Advanced aerostatic analysis of long-span suspension bridges

As the span length of suspension bridges increases, the diameter of cables and thus the wind load acting on them, the nonlinear wind-structure interaction and the wind speed spatial non-uniformity all increase consequently, which may have unnegligible influence on the aerostatic behavior of long-span suspension bridges. In this work, a method of advanced aerostatic analysis is presented firstly by considering the geometric nonlinearity, the nonlinear wind-structures and wind speed spatial non-uniformity. By taking the Runyang Bridge over the Yangtze River as example, effects of the nonlinear wind-structttre interaction, wind speed spatial non-uniformity, and the cable＇s wind load on the aerostatic behavior of the bridge are investigated analytically. The results showed that these factors all have important influence on the aerostatic behavior, and should be considered in the aerostatic analysis of long and particularly super long-span suspension bridges.

Experimental research on breakup of 2D power law liquid film

On account of limited knowledge of the breakup of power law liquid film, the process of its disintegration and atomization was studied by using a planar liquid film. A linear stability analysis was adopted to predict the breakup characteristics of the power law film. The predicting formulas of stripping breakup length and diameter of ligament were put forward presently. Through high-speed photography and laser light sheet illumination,different breakup characteristics of flat power law film under different conditions were derived. The characteristic dimension of breakup regimes were defined and extracted. The effects of several parameters(injection pressure,ambient pressure, nozzle structure and fluid property) on the stripping breakup length and spray angle were investigated. The results revealed that increasing both the velocity of liquid film and the ambient pressure facilitated the breakup of film, reduced the stripping breakup length and enlarged the spray angle in different extents. The comparison between theoretical and experimental results was conducted to validate the feasibility of the linear stability theory.

伪随机交织器的FPGA设计与实现

首先分析了伪随机交织器在Turbo码中的重要作用,讨论了交织器的设计准则,给出了一种采用m序列的伪随机交织器的硬件电路实现方案。设计中利用Matlab平台上的DSP Builder工具实现伪随机算法,并基于开发软件QuartusⅡ进行了程序设计、功能仿真和综合。该交织器具有易于实现、占用硬件资源少、适应数据可靠性传输等优点。

A Class of Constacyclic Codes over Ring R+vR

By constructing a Gray map, a class of constacyclic codes over ring R = R＋ vR is studied. Using cyclic codes and negacyclic codes of length p^s over ring R, the structure of （1 - 2v）-constacyclic codes and dual codes of length p^s over ring R are given, the Gray images of （1 - 2v）-constacyclic codes in a particular case are also studied. It is shown that linear codes of length pS over ring R are （1 -2v）-constacyclic codes if and only if their Gray images are distance-invariant cyclic codes of length 2p^s over ring R.

Ordinary Mode Instability in a Cairns Distributed Electron Plasma

Employing the linearized Vlasov-Maxwell equations, a generalized dispersion relation for the ordinary mode is derived by employing the Cairns distribution function. The instability of the mode and its threshold condition is investigated. It is found that the temperature anisotropy χ= TⅡ I⊥〉 1 required to excite the instability varies with density values whereas the growth rate is dependent on various parameters like non-thermMity A, equilibrium number density no and temperature anisotropy. It is found that with the increase in the values of any of the parameters A, no and X, the growth rate is enhanced and the k-domain is enlarged. The results are applicable for space plasma environments like solar wind.

Topological Properties of Fibonacci Networks

The Fibonacci numbers are the numbers defined by the linear recurrence equation, in which each subsequent number is the sum of the previous two. In this paper, we propose Fibonacci networks using Fibonacci numbers. The analyticai expressions involving degree distribution, average path lengh and mean first passage time are obtained. This kind of networks exhibits the smail-world characteristic and follows the exponential distribution. Our proposed models would provide the vaiuable insights into the deterministicaily delayed growing networks.