复杂系统的变结构分析

传统的变结构研究方法都是建立在模型基础上的 ,变结构分析主要集中在系统运行模型中参数的变化或变量的增减问题上 .这种传统的分析方法只限于人们对未知系统的模型结构有一个大致的了解 ,在一系列先验假设的条件下才能进行 .但是在系统建模之前 ,人们很难预先知道系统的运行的模型形式 .,对复杂系统而言 ,传统的变结构分析方法就难以奏效 .特别地 ,对非线性向量时间序列系统而言 ,系统内部动态均衡结构的变化不仅具有空间结构 ,而且具有一定的时间结构 .针对这种实际情况 ,本文提出了一种新的变结构分析思想 ,利用神经网络技术对系统的运行规律的结构变化情况进行了分析 .利用上海股市数据进行了实证研究 。

跨断层形变的慢时变结构分析与异常识别初探

甘肃及与青海、宁夏交界区布设有50多处跨断层短水准观测场地，20世纪80年代末起测并基本于每年的3，7，11月观测，2004-2008年曾加密为每年6期；控制了祁连山-海原-六盘山断裂带及西秦岭构造区；多数测线跨度数百米、个别测线达1km左右。其形变测值时序变化能直接反映所控制断层段的运动变化过程，具有强震预测的中短期前兆意义。

TX-1600G数控镗铣加工中心镗削系统变结构动态特性分析

针对镗削系统振动对加工零件精度影响问题,以TX-1600G数控加工中心镗削系统为研究对象,利用三维建模软件对镗削系统进行实体三维建模,并以镗削主轴进给量和镗滑台位置为参数,离散化镗削系统加工空间,对镗铣系统典型工作位置进行模态仿真,通过对镗削系统典型工作位置模态云图分析,选择动态特性良好的工作空间进行零件加工,提高零件加工精度,并为加工中心的整体分析优化提供参考参数。

溃变原理—结构分析法在强对流天气中的应用

溃变原理 [1]—结构分析法是欧阳首承教授经过三十多年的潜心钻研 ,研究出来的一套新的理论和方法。其核心就是要充分利用非均匀或不连续的真实信息 ,来预报天气演化的转折性变化 ,而天气演化的实质 ,既是大气涡旋转移式的演化。在天气预测的分析中 ,以涡动的旋矢性、风矢的不连续性、超低温和反序量 [2 ]构成结构分析体系 ,在天气的转折性变化和雷暴、暴雨、大风等强对流天气的预测中取得了成功。“旋矢性”是通过分析某个测站垂直方向上整层风矢的顺时针或逆时针滚流结构 ,来判断天气的转折 ;“超低温”是通过分析对流层顶或平流层底大气的超低温现象 ,即位温随气压的下降而陡然降低或不变 ,来预测灾害性天气 ;通过分析风场的不连续带来确定“次涡旋” ;“反序量”即按照风、湿、温、压的顺序 ,而非压、温、湿、风的顺序分析信息 ,提前抓住溃变信息。

不完全状态信息随机系统的变结构控制

根据完全状态信息下随机系统的变结构控制（ＳＶＳＣ）理论进一步研究不完全状态信息下随机系统的变结构控制问题，得到了变结构控制策略，研究了系统的渐近行为。仿真结果表明所得到的变结构控制策略是有效的。

筒型翅片管换热器空气侧换热模型分析与实验

本文对筒型翅片管换热器的空气侧流动特点进行了理论分析,基于现有换热模型提出了一种能够反映筒型翅片管换热器结构特点的集中参数形式的换热因子关联式。通过实验对比了筒型和普通型的换热因子,对理论分析进行验证,结果表明:现有换热模型对筒型翅片管换热器的预测误差较大,平均相对误差达到81.16%;对传统换热器预测较准,平均误差为7.53%;使用本文实验数据拟合后的新关联式对筒型换热器平均相对误差仅为8.86%,对传统换热器平均误差为8.80%,且误差分布均匀,大幅提高了关联式对筒型翅片管换热器的预测精度,也保持了对传统换热器的预测精度。

中国农业生产资料价格上涨原因的变结构协整分析

本文利用1978-2010年的年度时间序列数据对中国农业生产资料价格上涨的影响因素进行了变结构协整分析，发现成本推动和需求拉动是农业生产资料价格E涨的重要原因，如果农业生产资料成本和需求分别再增加1％，农业生产资料价格将分别上涨0．4301％和0．4687％，从而验证了已有研究结论。本文的研究还表明，农业生产资料生产和进口企业因在市场上具有垄断地位，可以凭借其垄断地位涨价，即使在控制住农产品价格上涨导致农业生产规模扩大的需求拉动影响之后，农业生产资料价格与农产品价格几乎仍然以相同幅度上涨，大大降低了农产品价格政策的绩效。为了提高农产品价格政策的绩效，必须改变农业生产资料市场结构，将分散的小规模农户组织起来，统一购买，提高农民的谈判能力，促进农业生产资料市场向竞争性市场转变。

多回路气动伺服弹性系统稳定裕度的变结构μ分析方法

作为一个多输入多输出(MIMO)系统,气动伺服弹性系统的各控制回路是相互耦合的,但对于各控制回路的稳定裕度目前尚无统一的计算方法。针对MIMO控制系统的稳定裕度计算问题,首先分析了现有的回差阵奇异值方法和μ分析方法,并指出了2种方法各自保守性的来源。在此基础上,提出了一种变结构μ分析方法,通过迭代调整扰动模型结构来求解稳定裕度,并从理论上证明了算法的单调收敛特性。以某弹性飞机的阵风减缓控制系统为例进行了稳定裕度分析。3种方法结果的对比表明,本文方法能够有效降低分析结果的保守性。

Increasing the toughness while reducing the viscosity of carbon nanotube/ polyether imide/polyether ether ketone nanocomposites

Polyether ether ketone(PEEK)has good mechanical properties.However,its high viscosity when molten limits its use because it is hard to process.PEEK nanocomposites containing both carbon nanotubes(CNTs)and polyether imide(PEI)were pre-pared by a direct wet powder blending method using a vertical injection molding machine.The addition of an optimum amount of PEI lowered the viscosity of the molten PEEK by approximately 50%while producing an increase in the toughness of the nanocom-posites,whose strain to failure increased by 129%,and fracture energy increased by 97%.The uniformly dispersed CNT/PEI powder reduced the processing difficulty of PEEK nanocomposites without affecting the thermal resistance.This improvement of the strength and viscosity of PEEK facilitate its use in the preparation of thermoplastic composites.

影响中长期电力需求的经济社会发展指标体系研究

电力需求与经济社会发展紧密相关,是经济、产业结构、人口、城市发展、科技进步等因素综合作用的结果。从经济发展、社会发展、能源电力、科技发展4个方面出发,分析经济社会发展各因素对电力需求的影响,利用因子分析、变结构协整分析等方法筛选指标,全面、系统地论证了影响电力需求的因素,构建影响中长期电力需求的经济社会发展指标体系。

Morphological,Anatomical and Genetic Analysis for a Rice Mutant with Abnormal Hull

A mutant with abnormal hull was first discovered from a twin-seedling strain W2555 in rice （Oryza sativa L.）. The mutant had sparse branches and decreased number of florets from the base to the peak. Frequently, the florets at the top of the panicle did not develop completely. The underdeveloped florets often showed slender and white in their life cycle. Genetic analysis indicated that the mutant traits were controlled by a single recessive gene （temporarily designated as ah）. ah gene controlled the development of inflorescence meristem and the flower organ. The florets of mutant showed degenerated lemma and palea. Stamens and lodicules were homeoticly transformed into pistils and palea/lemma-like structures, respectively. It seemed that ah mutant phenotypes of the homeotic conversions in lodicules and stamens were very similar to that of the B loss-of-function spwl gene reported previously in rice.

Application of the Blown-Ups Principle to Thunderstorm Forecast

Discontinuous and long-duration thunderstorm weather, which occurred at Guanghan in Sichuan Province, was analyzed and predicted using structural conversion of irregular information in phase-space from self-recording “time sequence” records for predicting rain areas, as described in the “Non Destructive Information” method proposed by Professor OuYang Shoucheng. The results show that this method can reveal important changes of weather as well as, by using irregular self-recording information recorded every ten minutes, predict local thunderstorms with durations of only half an hour, and even predict intense convections 12 hours in advance. This is significant for civil and military aviation. It shows the necessity of full utilization of information from automatic weather stations and the necessity of improvements in recording modes in current automatic stations.

Structural Variation Analysis of Mutated Nannochloropsis oceanica Caused by Zeocin Through Genome Re-Sequencing

Zeocin can cause double strand breaks of DNA and thus may be employed as a mutagen. In this study, two strains of Nannochloropsis oceanica, the wild and the Zeocin-tolerant strains, were re-sequenced to verify such function of Zeocin, The results showed that Zeocin can mutate the N. oceanica genome and cause the structural variation. Zeocin either swept away or selected the alleles of genes functioning in ubiquitin-mediated proteolysis, alpha-linolenic acid metabolism, ascorbate and aldarate metabolism, ribosome biogenesis, and circadian rhythm, indicating that N. oceanica may have adjusted its metabolic performances for protein, carbohydrate, and lipid, and changed its ribosome biosynthesis and living rhythm to survive in Zeocin containing medium. In addition, Zeocin caused mutation may have influenced the expression of a set of tanscription factors. It was concluded that Zeocin effectively caused the structural variation of the genome of N. oceanica, and forced the microalgae to select out the alleles of a set of genes around these variations in order to adapt to Zeocin containing medium. Further studies on the genetic basis of the phenotypic adaptation of this haploid and asexual microalga and the application of Zeocin to its genetic improvement are very important.

Deformation-based freeform feature reconstruction in reverse engineering

For reconstructing a freeform feature from point cloud, a deformation-based method is proposed in this paper. The freeform feature consists of a secondary surface and a blending surface. The secondary surface plays a role in substituting a local region of a given primary surface. The blending surface acts as a bridge to smoothly connect the unchanged region of the primary surface with the secondary surface. The secondary surface is generated by surface deformation subjected to line constraints, i.e., character lines and limiting lines, not designed by conventional methods. The lines are used to represent the underlying informa-tion of the freeform feature in point cloud, where the character lines depict the feature’s shape, and the limiting lines determine its location and orientation. The configuration of the character lines and the extraction of the limiting lines are discussed in detail. The blending surface is designed by the traditional modeling method, whose intrinsic parameters are recovered from point cloud through a series of steps, namely, point cloud slicing, circle fitting and regression analysis. The proposed method is used not only to effectively and efficiently reconstruct the freeform feature, but also to modify it by manipulating the line constraints. Typical examples are given to verify our method.

Spectroscopic Analysis of Structural Transformation in Biodiesel Oxidation

The oxidation behavior of three biodiesels of different origins,viz.rapeseed oil derived biodiesel,soybean oil derived biodiesel and waste oil based biodiesel,were tested on an oxidation tester.The chemical compositions of the biodiesels were characterized by gas chromatography.Thereafter,the structural transformation of fatty acid methyl ester(FAME)of the biodiesels was analyzed by an infrared spectrometer and an ultraviolet absorption spectrometer.The results demonstrated that the oxidation behavior of biodiesels of different origins was closely related to the composition and distribution of FAMEs.Higher concentration of unsaturated FAME with multi-double bonds exhibited poorer oxidation resistance.Furthermore,cis-trans isomerization transformation occurred in the unsaturated FAME molecules and conjugated double-bond produced during the oxidation process of biodiesel.Greater cis-trans variations corresponded to deeper oxidation degree.The higher the content of unsaturated FAME with multi-double bonds in a biodiesel,the more the conjugated double bonds was formed.

Analysis on Genomic Structure Changes and Diversity of Introgression Lines in Dongxiang Wild Rice(Oryza rufipogon Griff.)

[Objective] The aim of the study was to make research on genomic struc- ture variation and variety analysis of Dongxiang wild rice. [Method] Introgression groups of BC1F6 were based on donor of Oryza rufipogon Griff. and receptor of O. sativa sp. indica Kate. Strains of 239 in the group were analyzed on Polymor- phism with the help of 25 couples of SSR primers distributed in 12 pairs of chromo- somes. [Result] Gene fragments of O. rufipogon Griff. were found penetrated in the 25 microsatellite sites and most of the groups kept the parents of Xieqinzao B or DNA sequence of O. rufipogon Griff. The average rate of recurrent homozygous bands was 78.13% in the ILs, but the highest was 94.98% （amplified by primer RM131） and the lowest was 60.25% （RM171）. The average rate of donor homozy- gous bands was 13.37%, but the highest was 32.64% （RM171） and the lowest was 2.93% （RM1095）. There were numerous heterozygous sites in the population and the average heterozygosis rate was 5.62%, while the highest was 10.04%（RM401）. Moreover, we found some parental fragments were lost and some novel fragments were not detected in either parent in BC1F6 population. The average rate of lost bands was 2.88%, while the highest was 13.39% （RM311） and the lowest was 0 （RM401）. The average rate of new bands was 1%. The average of Nei＇s gene di- versity （He） and Shannon＇s Information index （I） were 0.276 and 0.457 respectively in high generation of introgression lines. [Conclusion] The study demonstrated that distant hybridization led to extensive genetic and epigenetic variations in high gener- ation of introgression lines, which expanded the base of genetic variation and laid an important foundation for rice improvement and germplasm innovation.

Splitting PMMA with Mini Cutting Explosives

In order to improve the present aviation ejection escape system, the application of explosion cutting technique to aviation escape system is proposed to weaken the strength of canopy before ejecting it. A series of mini cutting explosives are designed to investigate the process of splitting PMMA plate. The phenomenon of spallation in PMMA is observed. The effects of different parameters of mini cutting explosives on the cutting depth are obtained. Consequently the appropriate material of half-circular metal covers, explosive types and the ranges of charge quantities are determined. On the other hand, the cutting process of aviation PMMA plate by mini cutting explosives is simulated by means of nonlinear dynamic analysis code LS-DYNA. In finite element analysis,Arbitrary Lagrangian Euler (ALE) algorithm is used to depict the fluid property of high energy explosives. Continuous damage material model is used to simulate the complicate dynamic damage behavior of PMMA due to explosion shock waves. Only sliding contact option is defined to fulfill the fluid-structure interaction between explosives and PMMA plate by distributed parameter methods. Phenomenon of spallation observed in the experiment is presented in the simulation. The relationship between the penetration depth of PMMA plate and charge linear density obtained by numerical simulation agrees well with experimental result.

Effect of CuO and SnO_(2) particle size on hot extrusion deformation of AgCuOSnO_(2):Finite element simulation and experimental study

The finite element model is established according to the experimental results,and then the experimental results are verified by simulation calculation.In terms of the combination of finite element analysis and experiment,the effect of particle size of CuO and SnO_(2) on the stress,strain and microstructure of AgCuOSnO_(2) composite during hot extrusion was studied.The results illustrate that with the decrease of particle size,the dispersion of the second phase increases gradually,while the possibility of“tail shrinkage”of the billet decreases continuously;cubic CuO will evolve to fibrosis,and the degree of fibrosis will increase with the decrease of the particle size and ring clusters.Specifically,the degree of fibrosis at the middle end of the billet is higher than that at the front end,the degree of fibrosis at the front end is higher than that at the back end,and the degree of fibrosis on the surface is higher than that in the core;part of CuO fibers will bend,and the degree of buckling strength is positively correlated with the size of particles and their annular clusters.Additionally,there is fiber CuO in the front and back end of the billet that are inconsistent with the extrusion direction,and the degree of difference was negatively correlated with the particle size.

Creep characteristic simulation of deep soft rock roadway and long-term mechanical analysis of lining support

By the generalized Kelvin creep model,rheological characteristics of deep softrock and long-term mechanical behaviors of support structures were simulated.Mechanicaldeformation characteristics of support structures under different lining circumstanceswere also analyzed on the basis of deducing the relationship between the generalizedKelvin creep model and implicit creep equations in ANSYS FEM software.The resultsshow that high stress of deep tunnels is the main factor in creep damage;the surroundingrock's deformation binding effect due to lining increases as the thickness increases but theeffect becomes very weak when it increases to a certain value;contact pressure on thelining decreases as its thickness decreases.

Parameter Variations of Identified Model for Static Deformation Analysis of Arch Dam

The structural health monitoring of a dam is important for maintaining the safe operation and longevity of the dam system. The structural health of a large dam can be monitored from the measured static deformation. This paper presents an investigation of the parameter variations of the identified model of the measured long-term static deformation for the structural health monitoring of Fui-Tsui Dam, which is located in a very active seismic zone of Taiwan. The measured static deformation is characterized as a function of the measured physical parameters, including the effects of hydrostatic pressure and temperature variation. The identified parameters, associated with the effects of hydrostatic pressure and temperature variation, change with environmental factors, such as flooding, earthquake and foundation change.