地图数字化数据质量控制方法

源误差、处理误差和应用误差是空间数据误差的3种类型,源误差通常远远大于处理误差,因此源误差对地图数字化数据质量显得尤为重要．在分析数据采集误差的基础上,提出了地图数字化数据质量控制方法．     

一种增加动基座飞行器误差分离结果稳定性的半解析方法

动基座发射飞行器存在初始误差大、初始误差和工具误差强耦合等特点,相比静基座发射,其误差分离过程更为复杂针对上述问题,提出了一种增加动基座飞行器误差分离结果稳定性的半解析方法,建立了初始定位误差、初始速度误差的解析求解模型,采用了迭代方法对初始误差和工具误差进行联合求解.通过算例对比分析半解析误差分离方法和传统误差分离方法,结果表明:半解析方法中基于遥外测视位置和速度差分离初始误差,观测数据与误差量直接对应,并结合解析方法精准高效的特点,能够有效提高动基座飞行器误差分离结果稳定性.     

光纤陀螺标定误差对舰船捷联惯导系统的影响

为降低船用光纤陀螺标定误差对捷联惯导系统的影响,有针对性地提高光纤陀螺各标定参数的精度,采用将光纤陀螺标度因数误差、安装误差和零位误差进行分离的方法,推导出光纤陀螺三种标定误差与舰船角速率误差之间的函数关系,将其分别代入舰船捷联惯导系统姿态误差方程进行误差分析.并将舰船摇摆运动下的导航误差与静止下的导航误差进行比较.研究结果表明:光纤陀螺零位误差等效于光纤陀螺漂移,舰船摇摆运动会激励光纤陀螺标度因数误差和安装误差的标定误差对系统的影响.     

环境温度影响下交叉杆并联机床的误差分布

环境温度作为影响并联机床加工精度的误差源一直被忽视,为提高机床的加工精度,研究了环境温度影响下并联机床的误差分布特性。用全微分法建立机床的误差模型,根据该模型计算工作空间内各点的径向误差和轴向误差,用Matlab绘制各误差的空间分布图及各离散层上的误差等值图,得到了各误差的分布形态及分布规律,并对误差分布规律进行了试验验证。研究表明,径向误差主要受刀轨半径的影响,轴向误差受刀尖点轴向坐标和刀轨半径的共同影响。工作空间边缘区域径向误差较大,向中心区域递减;轴向误差反之。提出误差等值图可用来分析和估算环境温度对并联机床加工误差的影响。     

GPS观测误差及其相应的处理方法研究

GPS测量含有多种误差,根据误差的来源可将其分为三类：与GPS卫星有关的误差;与信号传播有关的误差;与接收机有关的误差。根据误差的性质,这些误差又可分为系统误差和随机误差两类。系统性的误差主要包括：卫星轨道误差、卫星钟差、电离层延迟、对流层延迟、接收机钟差和接收机位置误差。随机误差主要包括多路径效应误差和接收机噪声。     

3DP工艺中阶梯误差与渗透误差相互作用研究

3DP工艺中影响零件成型精度的原理性误差主要来源于阶梯误差和黏结剂渗透误差,并且在误差测量结果中难以区分．本文基于黏结剂在砂床中的流动状态,建立了黏结剂从喷射到渗透过程的数值仿真模型,分析了在二维平面不同角度三角面片打印时理想模型边界和实际黏结砂粒边界之间的位置误差,研究了阶梯误差和渗透误差之间的相互作用．在此基础上,针对不同角度三角面片打印过程中阶梯误差与黏结剂渗透误差相互作用关系也不相同的问题,提出了基于三角面片法向量方向与成型方向夹角的三角面片偏移误差公式用于表达这两种误差对成型质量的综合影响．结果表明：在向上三角面片中,渗透误差与阶梯误差相互补偿,三角面片偏移误差随着斜面与水平面夹角角度的减小而减小;在向下三角面片中,阶梯误差与渗透误差相互叠加,三角面片偏移误差随着斜面与水平面夹角角度的减小而增大．将三角面片偏移误差的公式计算值与其实际测量值进行对比,公式计算误差最大为0.060 mm,最小为0.002 mm,表明三角面片偏移误差公式用于表达阶梯误差与黏结剂渗透误差综合作用的有效性.     

多因素综合作用的摆线针轮传动误差分析

摆线齿轮的齿廓修形以及制造误差是影响摆线针轮传动精度的关键因素,为了分析多因素综合作用下摆线针轮传动的误差,基于齿轮啮合原理和坐标变换,通过构建考虑齿廓修形、加工误差和装配误差等综合因素的摆线齿轮齿廓方程,得到多因素综合作用下的摆线针轮啮合副误差分析模型。该模型可实现齿廓修形、加工和装配误差等因素综合作用下摆线针轮传动误差的分析计算,分析各误差因素以及多因素作用对传动误差产生的影响。结果表明：摆线轮齿距累积误差对传动误差的影响最大;摆线轮廓度误差和装配误差的影响次之;针齿半径误差和针齿位置半径误差的影响最小。     

基于状态空间模型的飞行器角误差控制

针对飞行器装配角误差过程控制问题,提出了基于状态空间模型的逐步最小化角误差法及全局最小化最终角误差法,并与直接装配法进行了对比.研究结果表明:直接装配法角误差服从莱斯分布并逐渐增加;逐步最小化角误差法和全局最小化最终角误差法角误差服从广义极值分布,逐步最小化角误差法不受装配零件个数的影响,全局最小化最终角误差法角误差均值与标准差均随零件增加收敛于0.     

全野外数字化测图精度探讨

全野外数字化测图的方法已被普遍应用,但从全野外数字测图的实际作业来看,它的可靠性和精度仍应引起注意。全野外数字测图的误差来源主要有:测点误差(仪器误差和观测误差)、测站误差、棱镜偏心误差以及人为操作引起的误差,其中棱镜偏心误差和人为操作误差不容忽视。     

序列运算离散化过程中的误差成因及补偿

为了减少序列离散化过程导致的误差,提出几种概率补偿的方法。由误差的成因入手,分析了离散化过程的误差机理,将利用随机变量的概率分布函数离散化后所得序列,分别以修正公式、平均补偿法及比例补偿法进行补偿,推导出各种误差补偿方法下序列期望值及方差的误差估计公式。结果表明:经误差补偿后,算例中序列期望值误差下降为原误差的8%以下,而方差误差至少可降为原误差的91%。     

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.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the