极——零点配置自校正调节器的在线优化

极-零点配置自校正调节器在实际使用中,通常存在如何合理配置闭环极点的问题.本文运用非线性优化原理,基于系统跟踪误差指标最小的原则,建立起具有极点参数在线优化的自校正控制,使系统在参数自适应的同时,实现闭环特性最优化.     

控制理论中误差系数和零极点问题的讨论

本文根据静态和动态误差系数的定义,讨论了静态误差系数的物理意义,并用动态误差系数计算了系统在不同输入条件下的误差函数e(t),并在此基础上对两类误差系数进行了比较。此外,在系统开环零极点、闭环零极点的定义的基础上,推导出两类零极点间的关系及其在根轨迹上的位置,并着重讨论了闭环零点对系统瞬态响应的影响。     

峰值电流模BUCK变换器的建模及稳定性设计

基于小信号建模思想,建立了电感电流连续模式(CCM)下的BUCK变换器完整的小信号模型,推导出了控制-输出传递函数.通过分析电流采样对系统稳定性的影响及控制-输出传递函数中的零极点位置,提出一种电压环补偿电路,该结构产生了一对频率不同且随Cm变化的零点和极点,可用以灵活地对环路带宽及相位裕度进行微调.利用Matlab及Hspice仿真,验证了该建模方法及补偿方案的正确性,仿真结果表明:补偿后的变换器低频增益可达55dB,带宽为225kHz,相位裕度达到74°,环路在各种负载下均表现出优良的稳定性.     

稳健的可变速率机动目标跟踪方法

为了解决带宽受限的多传感器跟踪系统中机动目标的精确跟踪与带宽的有效利用这一主要矛盾,提出了一种稳健的可变速率机动目标跟踪方法.通过对系统中的非线性部分的分析,明确了目标机动、输入数据速率对跟踪系统模型不确定性的影响,从而得到以目标机动特性为依据动态调节数据采样频率的稳健跟踪方法.仿真试验表明,该方法在稳健跟踪的同时减少了系统通信负担,尤其适用于通信带宽受限的机动目标跟踪系统.     

系统零极点分布对系统性能的影响

为进一步理解系统的性能与系统零极点分布的关系,在已有系统函数的基础上,增加零极点并绘制零极点改变前后的系统根轨迹曲线、系统阶跃响应曲线,观察系统根轨迹曲线的变化趋势和系统阶跃响应的变化速度、振荡波动幅度,得出零极点分布对系统性能、根轨迹曲线变化趋势的影响的结论.理解零极点分布和系统根轨迹曲线的变化趋势以及系统性能之间的联系,可以为系统设计和分析提供理论支撑.     

船舶航向无静差跟踪控制系统设计

为了提高航向控制系统适应能力和降低控制器参数设计复杂性,在内模控制的基础上设计了一种专门针对船舶航向控制的无静差跟踪控制系统,推导了控制器参数与闭环系统零极点位置的关系,针对静水域环境下一组航速分别进行了仿真研究,测试了航向控制系统的鲁棒性和机动性能.仿真结果表明本文所设计的控制器达到无静差航向控制,并具有较好的鲁棒性.     

激光跟踪系统“鸟巢”坐标的球面标定法

深入分析了激光跟踪测量系统坐标系的特点,建立了采用高精度约束球面标定激光跟踪测量系统(LTS)的初始状态参量和结构误差参量的方法.通过数学仿真搜索出采用约束球面进行系统标定时的最佳约束球半径、最佳采样点个数等,并采用仿真方法评估系统噪声对标定结果的影响.使用三坐标测量机和QC20-W高精度伸缩球杆仪建立了球面约束标定的实验装置,对激光跟踪系统执行了球面约束标定实验.实验结果表明,采用高精度约束球面作为约束条件可以提高系统的未知参数标定精度和测量精度.     

基于稳定性原理的参数调节器在气动机械手中的应用

研究了关节型球面坐标气动机械手中的执行部件--气动摆缸的角位移控制方法.根据李亚普诺夫稳定性原理构造最优指标函数,由指标函数推导出使系统输出的跟踪误差趋于零的系统参数调节律,并通过仿真及实验分析了调参系数对气动摆缸角位移控制系统动态性能的影响.实验结果表明,基于稳定性原理的参数调节器使系统达到了对期望输出的精确跟踪,而且保持了控制过程中闭环系统的全局一致稳定性.     

结合信赖域和粒子滤波的红外目标跟踪方法

研究机载前视红外(FLIR)系统中鲁棒的目标跟踪算法.在传统的粒子滤波中嵌入信赖域寻优方法,发挥了它们各自的优点.在重要性重采样之前,将所有的粒子点都置于状态空间中恰当的位置,只用少量的粒子点就可以保持住多个模态,并解决了传统粒子滤波中的采样恶化和采样枯竭问题.实验结果显示了该方法的有效性和鲁棒性.     

一类模型跟随自适应控制方法及其在高响应电液位置伺服系统中的应用

从零极点配置结构图出发,导出了一类模型跟随自适应控制方法。该方法能够有效地处理含纯时延环节的过程的控制问题,理论上不要求被控过程与参考模型具有相同的零点。并讨论了该方法在高响应电液位置伺服系统中的应用。实验结果表明,该方法对于低频信号(方波及正弦波)具有相当高的跟踪精度。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to