核磁共振技术在生命科学领域的应用

从磁悬浮陀螺寻北仪的寻北原理出发,将地球自转角速度分解到陀螺坐标系上,分析了存在准直误差的情况下所引起的寻北误差,推导出了用于补偿运算的准直误差与寻北误差之间的关系表达式,避免了精确准直消耗时间造成总寻北时间延长的问题。实际应用结果表明:准直范围由3″扩大到1′,可缩短磁浮闭路时间约60 s,通过测量准直误差并补偿,仪器总寻北精度没有改变。     

基座晃动对寻北仪影响的仿真分析

外界对寻北仪的干扰,选取正弦和正弦衰减情形,采用二位置寻北方案及改进寻北算法进行仿真,允许基座在大倾角情况下确定方位,即横滚角和俯仰角可不近似为零.计算机控制力矩电机带动旋转机构使陀螺、加速度计由初始位置转动180°采样,再反向转动180°回到初始位置重采样,根据各通道的两次脉冲总数计算航向角、横滚角和俯仰角.仿真结果说明在基座晃动情况下,寻北仪未经有效补偿无法准确寻北.     

具有倾角补偿的快速寻北仪系统研究

介绍了一种能在静态下全天候、全方位、快速、实时的陀螺自动寻北仪,本寻北仪采用二位置寻北,二位置寻北方案结构简单、实现方便和精度高等优点得到广泛应用.寻北仪利用陀螺和加速度计分别测量地球自转角速度的分量及载体的倾角.寻北算法里包含了载体倾角补偿内容,不需将载体完全调平,在小倾角的条件下就能够自动寻北,最后通过数码显像管或串口通讯输出载体的某一固定轴与真北方向的夹角.     

具有倾角补偿的快速寻北仪系统研究

介绍了一种能在静态下全天候、全方位、快速、实时的陀螺自动寻北仪,本寻北仪采用二位置寻北,二位置寻北方案结构简单、实现方便和精度高等优点得到广泛应用。寻北仪利用陀螺和加速度计分别测量地球自转角速度的分量及载体的倾角,寻北算法里包含了载体倾角补偿内容,不需将载体完全调平,在小倾角的条件下就能够自动寻北,最后通过数码显像管或串口通讯输出载体的某一固定轴与真北方向的夹角。     

某型炮兵雷达探测系统自动寻北标定仪总体设计与实现

针对气象探测前进行人工寻北标定存在的问题以及研制自动寻北标定仪的必要性,在从组成及功能2个方面对自动寻北标定仪进行分析的基础上,提出了该系统的数字化设计与实现,实践应用表明,该寻北仪各项指标达到了设计需求。     

恒速偏频激光陀螺寻北仪的研究

文中介绍了恒速偏频激光陀螺寻北仪的工作原理，分析了其寻北算法，在此基础上进行了实验。理论分析和实验表明恒速偏频激光陀螺寻北仪的精度和激光陀螺的随机游走成正比，和总寻北时间的平方根成反比。     

捷联式陀螺寻北仪误差分析与试验研究

对产生捷联式挠性陀蚴寻北仪误差的主要因素进行了分析。试验结果表明：水平姿态角较 ,与重力加速度的一次项有关的陀螺漂移是产生建立经误差的主要原因之一。应用椭圆低通滤波器对陀螺仪输出信号进行处理,能较好地减小基座扰动对寻北精度的影响。     

二位置光纤陀螺寻北方案及误差分析

为消除陀螺零偏和陀螺常值漂移的影响,探讨二位置方案来实现高精度寻北的方法;并以二位置寻北原理为基础,给出其误差分析方法,得出在陀螺的漂移及标度因数误差、台体的水平误差、转位误差、引入参数误差等几个因素作用下的误差模型,并对误差特点进行分析。分析结果证明:在以上误差源作用下产生的寻北误差多与方位角的三角函数成比例关系,或为常值误差,该结论可为补偿寻北误差提高寻北精度提供参考。     

带误差补偿的二位置寻北仪设计

带误差补偿的二位置寻北仪系统包括电源、转机结构、控制电路、计数器等.其补偿算法推导基于陀螺和加速度计一次误差补偿模型,以降低陀螺随机漂移及加速度计的零位漂移对寻北精度的影响.同时再利用由典型静态误差源产生的寻北误差与方位角三角函数成正比或为常值,以罗差修正寻北结果进一步提高寻北精度.     

摆式陀螺寻北仪快速寻北的时差逆转点法

针对现有粗寻北方法时间长精度差的不足,结合时差法和逆转点法提出一种综合快速寻北的时差逆转点法。由陀螺仪常数及地理信息求出摆动周期,然后测量摆动曲线中一个逆转点和两个相关点的时刻与摆幅,代入时差逆转点法模型解算出真北方向。通过实验验证,测量时间短,精度优于传统粗寻北方法。结合积分法精寻北,在7min内,寻北精度达到7″。     

Nitrosation and Nitration of Tetraacetyldibenzylhexaazaisowurtzitane

Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.     

A Robust Algorithm for Watermarking 2D Vector Maps with Low Shape-Distortions

The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS （geographical information system） data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.     

Open Rule-setting System Applied to Conceptual Design of Engines

Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.     

Research on Linux Network Device Driver

By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux （kernel version 2.6.11 ） is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

Experimental Study on the Small Flyer Initiating Behavior of Fine-grained Explosives

The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.     

Algorithm for Multi-laser-target Tracking Based on Clustering Fusion

Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.     

Influence of Installing Error on the Surface Shape Precision of the Axial Symmetry Aspheric Workpiece in Lapping

A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same.     

Experimental Research on Output Performances of Giant Magnetostrictive Actuator

The paper introduces the performances of magnetostrictive actuators and its applications, discusses the design methods for the structure and internal magnetic circuit of a giant magnetostrictive actuator, and makes tests on the output displacement and force characteristics for an actuator using homemade magnetostrictive material. The experimental result shows that the actuator has satisfactory output precisions and ranges in transient and stable states, and can be used in lowfrequency vibration control system of precise equipment.     

Robust Graded Sliding Mode Tracking Control for Low Speed Spinning Ballistic Missiles

The nonlinear dynamic model of spinning ballistic missiles is established during the first boosting phase of the missile. Based on the conventional backstepping sliding mode control and the assumption of a two time-scale separation of missile dynamics, a graded sliding mode controller is designed with two sub-sliding surfaces which have invariability to external disturbances and parameter perturbations, and a matrix which comprises three first order low pass filters is introduced to prevent ＂explosion of terms＂. Owing to the upper bounds of the uncertainties are difficult to obtain in advance, adaptive laws are introduced to estimate the values of the uncertainties in real-time. Eventually, the numerical simulation results given to show the proposed controller can ensure the steady flight of missiles.