高精度I-FOG光电转换的设计与实现

为了提高闭环干涉式光纤陀螺（I—FOG）检测精度,根据I—FOG的信号特征,说明了光电转换对陀螺后级信号处理的影响。详细分析了转换电路的噪声模型。基于微弱信号检测的方法,设计了应用AD8099实现的一种低噪声、高精度光电转换电路。经实验得到了优良的零漂、零偏、低噪声指标,可满足闭环I—FOG的实用要求。     

Yole发布RLG—FOG—DTG-石英和MEMS基惯性测量装置市场竞争性分析

Yole Developpment发布了一篇新报告：2007—2012年的IMU市场。报告的内容为RLG—FOG—DTG-石英和MEMS基惯性测量装置的市场竞争性分析。     

光纤陀螺寻北仪多位置寻北误差分析

在建立光纤陀螺（FOG）寻北仪误差模型和FOG误差模型的基础上，从理论上分析了FOG和加速度计的零偏、FOG零漂、地速和地磁场随方位的变化等对FOG、FOG寻北仪的影响以及FOG寻北仪产生多位置寻北误差的原因，并提出了减小多位置寻北误差的方法。最后，在FOG寻北仪中进行了实验，实验证明了理论分析的正确性和所采用的方法的有效性。     

中高精度光纤陀螺的误差分析及抑制措施

光纤陀螺（FOG）是惯性导航系统中新发展起来的一代惯性测量元件,其性能深受光源、多功能光电集成芯片及光电探测器等光电器件的影响。文章阐述了中高精度光纤陀螺的主要噪声机理,对两个不同精度等级的陀螺进行了Allan方差分析。根据FOG噪声参数估计值判断出FOG中白噪声和分形噪声的含量,从而验证了FOG的精度级别,并给出了不同精度FOG的改进方案,为提高FOG精度提供了理论指导。     

光纤陀螺温度漂移建模补偿

光纤陀螺(FOG)的核心部件对温度敏感,造成温度是影响FOG测量精度的主要原因之一.对FOG温度漂移进行建模是实现其温度补偿,提高FOG测量精度的有效方法.结合近年来FOG的研究成果,在分析FOG温度效应机理的基础上,对FOG温度漂移建模方法进行综述.特别针对FOG温度特性的复杂非线性特点,从光纤陀螺温度漂移建模原理、建模复杂程度、模型精度及模型通用性等方面对多种建模方法进行对比分析.     

光纤陀螺(FOG)小型化技术

在把FOG从实验室推向实用领域的研究过程中,FOG的小型化是必不可少的。本文基于对FOG电路和光路两个结构部分的分析,分别阐述了使FOG体积减小,重量减轻的几种途径。多轴陀螺的复用也是FOG小型化的重要途径,本文介绍了常用的几种     

一种用于光纤陀螺降噪的鲁棒平滑滤波算法

为了降低光纤陀螺(FOG)的随机噪声以及消除异常采样信号的干扰,提出一种鲁棒平滑滤波算法。利用权重函数为FOG每个采样数据迭代加权,给异常值分配较低权重给高质量数据分配较高权重,有效提高了平滑滤波的鲁棒性。采用广义交叉验证估计平滑参数再利用离散余弦变换计算原始FOG数据的平滑值,提高了平滑滤波的运算速度。软件仿真和实际实验结果表明,相比传统最小二乘平滑滤波算法,所提算法能够有效抑制FOG随机噪声和异常采样信号的干扰,并且对时变的FOG信号具有较好的跟踪能力。     

宽谱光源相对强度噪声及对闭环光纤陀螺影响研究

宽谱光源相对强度噪声(RIN)的定量评估及其对光纤陀螺(FOG)性能的影响机理是进一步提高FOG精度的关键问题。搭建实验测试系统对4种不同谱型、不同偏振态宽谱光源的RIN进行了独立测试,基于3种不同等效谱宽定义分别计算4种宽谱光源的RIN,通过对比确定了基于功率加权平均谱宽的强度噪声计算模型;在此基础上,对FOG的随机游走系数(RWC)模型进行了修正。搭建光电分离式高精度FOG实验系统,采用4种光源,分别测试了FOG的RWC,同时利用修正模型估算了RWC,实测值与估算值吻合较好。结果表明,光源的功率加权平均等效谱宽和偏振度是影响宽谱光源RIN的主要因素,该研究为光源RIN的评估和高精度FOG的优化设计提供了重要的理论和实践依据。     

闭环光纤陀螺的建模方法

在设计基于光纤陀螺（FOG）的惯性测量单元之前,必须首先获得陀螺的传递函数模型,研究的目的就是寻求一种有效的FOG传递函数的辨识方法。本文分析了传统方法辨识闭环FOG传递函数的困难,然后提出了利用速率转台对地球自转角速度的调制分量作为陀螺输入来辨识FOG传递函数的方法,并设计了基于最小二乘法的正弦信号幅值和相位的检测方法。通过对国外某FOG模型的分析说明了该方法的可行性,并且该方法实施简单,能够克服白噪声对信号幅值和相位检测带来的影响。     

基于长程光纤网络的谐振腔光纤陀螺

提出一种全新结构的基于长程光纤网络光调制谐振腔光纤陀螺(R FOG)系统,利用R FOG传感部件光纤环形腔的光纤长度短、体积小以及无源特点,将其通过长程光纤网络与后端的光源、探测器及复杂的信号处理部件连接起来,实现远距离的无源角速度探测。这种结构的R FOG具有很高的理论灵敏度可达5×10-8 rad/s,采用的全数字闭环处理方案能实现大动态范围信号检测,而且对转换器的要求不高。各种误差消除措施可以在系统中很方便的实现,大大提高陀螺性能。结合光纤系统的各种复用技术,该R FOG结构可以组成大型的远距离角速度惯性测量网络系统,有效地克服了传统R FOG在系统成本和复杂性上的劣势,为R FOG走向实用提供了新途径。     

谐振式光纤陀螺闭环锁频系统

谐振式光纤陀螺(R-FOG)是基于Sagnac 效应产生的谐振频率差来检测旋转角速率的一种新型光学传感器。利用闭环锁频系统可以减小光纤环形谐振腔受温度、应力等外界环境变化的影响,提高陀螺性能。提出了数字与模拟相结合的闭环锁频系统方案设计,克服了模拟锁频电路带来的电路温漂,采用模拟解调技术来降低了对系统A/D 转换器的转换速度的要求,同时无需对复杂数字解调算法的研究。闭环锁频系统应用于陀螺测试系统中,实验测得10 s时间内的锁频精度为2.15 ()/s。     

Key Dimensions of Inhibitors for the Deployment of Web-Based Business-to-Business Electronic Commerce

There has been a rapid increase in the number of firms undertaking business-to-business (B2B) electronic commerce (e-commerce) initiatives. Although there are various benefits to B2B e-commerce, there are also inhibitors to its deployment. This study empirically investigates the inhibitors for deploying Web-based B2B e-commerce applications in organizations. A field survey of senior IT executives was conducted to examine the key problems that inhibit the deployment of Web-based B2B e-commerce. A comprehensive list of inhibitors was derived from an extensive review of the literature and pretested with senior IT executives. Data from 249 firms were factor analyzed to yield the underlying structural dimensions of inhibitors impacting the deployment of Web-based B2B e-commerce. Univariate$ t$-test and multivariate discriminant analysis were carried out on the resulting ten dimensions to compare B2B (i.e., firms who have deployed B2B) and non-B2B firms (i.e., firms who have not deployed B2B). The results suggest that key inhibitors in B2B deployment are the lack of top management support, unresolved technical issues, the lack of e-commerce strategy, and the difficulties in cost-benefit assessment of e-commerce investments. Implications of the results for researchers and IT/engineering management executives are discussed.     

一种新的8B/10B编解码方案设计与实现

对现有不同的8B/10B编解码方案进行了介绍和分析,同时研究8B/10B的编码特点和内在相关性,在此基础上提出一种可移植性SB/10B编解码方法,用VHDL语言进行设计,给出了仿真和综合结果.将其嵌入到FPGA中可构成一个资源占用少、速度快、可靠性高、可移植的IP核,实现了具体的硬件电路,验证了设计方法的有效性和可行性.     

Ab initio study on physical properties of wurtzite,zincblende, and rocksalt structures of zinc oxide using revised functionals

To provide a more comprehensive understanding of zinc oxide (ZnO), the structural, optical, dielectric and thermodynamic properties of wurtzite (B4), zincblende (B3) and rocksalt (B1) phases are studied based on density functional theory with various revised functionals. It is found that the equilibrium volume, bulk modulus, phase transition point and covalent degree of B3-ZnO are close to those of B4-ZnO. Similar behaviors can be observed from optical properties, dielectric constants and Born effective charges. Moreover, thermodynamic parameters including isothermal bulk modulus, thermal expansion coefficients, Grüneisen parameter, and heat capacity with temperature of B3-ZnO are also in accordance with B4-ZnO. In contrast, B1-ZnO obviously undergoes dissimilar physical properties. Thus, it can be concluded that B3 phase may be the substitute of B4 phase in case of growing on the closely cubic lattice-matched substrates.     

[[2n, n]] ADDITIVE QUANTUM ERROR CORRECTING CODES

The self-orthogonal condition is analyzed with respect to symplectic inner product for the binary code that generated by [B1 I B2 B3], where B, are the binary n x n matrices, I is an identity matrix. By the use of the binary codes that generated by [B1 I B2 B2 BT1], asymptotic good [[2n, n]] additive quantum codes are obtained.     

Transport characteristics of a symmetrically extended bipolartransistor

This work deals with a novel bipolar transistor structure consisting of a δp(B*)-δn(E)-δp(B) planar doping layer sequence embedded between two heavily doped n⁺ collector layers C* and C. Currents flowing in such a n⁺δpδnδpn⁺ structure are investigated under symmetrical bias conditions (V_EB=V_EB *, V_BC=V_B*C*). At V_EB>0 (forward bias), electrons, injected from the E layer over the B(B*) barrier, are collected in the C(C*) layer whereas holes, injected from B and B* over the E barrier, are collected in the respective counter-layer B* and B. In this structure, at V_BC=0, the difference between the total current emitted from E and the current collected in C and C* equals the electron-hole recombination current between E and B (E and B*). Accordingly, the current gain depends linearly on the recombination lifetime in the E-B(E-B*) region. At reasonable lifetimes (τ=1 μs) appreciable current gain values are obtained even at high B(B*) doping levels     

LAAS地面站伪距纠正量误差完好性监测算法研究

该文推导了LAAS地面参考站系统中伪距纠正量误差公式,分析现有的伪距纠正量误差完好性监测算法B值排除法,得出结论:B值之间具有相关性,一个B值出错,会影响到其它B值;B值排除法没有把接收机故障和卫星故障分开考虑,会产生较大的误检和漏检概率。该文提出两种伪距纠正量误差完好性监测算法:行列判断法和C值辅助法。针对无故障和5种故障情况,通过仿真实验对3种算法进行了分析,结果表明两种新算法的误检、漏检、误排、漏排概率均小于原算法,进而提高了系统的定位精度和连续性。把行列判断法和C值辅助法进行对比,讨论各自优缺点,提出选择算法的依据。     

Service assurance across organisational boundaries with semantic mediation

This paper describes an approach to support OSS integration across organisational boundaries. The requirement for such B2B interfaces is expected to increase as is the need to carry out integration in a much more flexible way. Existing approaches for integration tend to be implementation specific, operate at the syntactic level, and are realised by program code. Consequently they are inflexible due to their highly coupled nature and are costly to set up and maintain. An approach to decouple B2B interfaces is introduced, which allows them to be flexibly coupled as required with the use of scalable, semantic mediation. A prototype based on an assurance integration scenario for BT Wholesale’s B2B gateway is described.     

A first principle study of pressure-induced effects on phase transitions,band structures and elasticity of zinc oxide

Using the first-principles projector-augmented wave (PAW) method, the pressure induced effects on solid–solid phase transition, electronic band structures and elasticity of zinc oxide are investigated. The four possible structures are considered here, including rocksalt (B1), CsCl (B2), zinc blende (B3), and wurtzite (B4). It is found that structural properties and phase transition points by the PBEsol method are better than those computed using the standard local density approximation and Perdew, Burke and Ernzerhof functionals. Moreover, using the hybrid HSE06 functional, the band structures around phase transition points are displayed. The predicted fundamental gaps of the four considered structures provide improvements over directly density functional theory calculations. Meanwhile, the effective masses for the electrons in the conduction band and the holes in the valence band are derived. Furthermore, the elastic abnormal behavior is achieved around the phase transition points. For B4, B1 and B2 structures, the longitudinal and transverse sound velocities are evaluated along significant symmetry directions with pressure, and it still awaits experimental confirmation.     

不谐和系数对钢琴音质的影响

从实验上研究了钢琴的不谐和系数B对主观听感的影响。通过对钢琴的原始录音进行分析，并对分析数据进行处理，合成出几个不同B值的钢琴音。合成音与原始录音的听感比较实验结果表明，B值对低音键的音质影响较为明显，过高或零的B值都会产生较差的音质。但在现有生产技术条件所给出的最低(B=0．00005)极限范围之上，减少B值可使钢琴的低音键在主观听感上较为厚实。