藕田养鱼巧除浮螺和青苔

在藕、鱼生长的前期,藕田会产大量的浮螺、青苔,与藕苗争肥。用硫酸水溶液巧除浮螺和青苔,效果很好。即在5～6月。

MODELING OF SCG ROTOR DRIFT AND MEASURING SCHEME

Based on micro-displacement measurement principles of the spherical differential capacitance sensor, the relationship between the capacitance variation and the micro-displacement of each pair of detecting electrodes for the superconducting gyroscope （SCG） with eight detecting electrodes is analyzed. The model of the SCG rotor drift is established through dimensionless processing, linearization within micro-displacement and the least-square approach. Both the measurement scheme of the SCG rotor drift based on the model and its parameter relationship are presented. To guarantee the potential of the suspension rotor to be zero, the distributing scheme of four pairs of detecting electrodes is presented. The scheme can measure the magnitude and the direction of the rotor drift. The negative factors for affecting the measurement precision of .the SCG rotor drift and simulation results of the total effects are given. Simulation results show that the distributing capacitance of these differential capacitance sensors, the zero potential of the rotor and the model error are the major negative factors. The methods for eliminating those negative factors and the application range of the model are given. The model ensures the relationship between the output voltage and the rotor drift be linear.

MEMS Inductor Consisting of Suspended Thick Crystalline Silicon Spiral with Copper Surface Coating

A novel MEMS inductor consisting of a planar single crystalline silicon spiral with a copper surface coating as the conductor is presented. Using a silicon-glass anodic bonding and deep etching formation-and-release process,a 40μm-thick silicon spiral is formed, which is suspended on a glass substrate to eliminate substrate loss. The surfaces of the silicon spiral are coated with highly conformal copper by electroless plating to reduce the resis- tive loss in the conductor,with thin nickel film plated on the surface of the copper layer for final surface passivation. The fabricated inductor exhibits a self-resonance frequency higher than 15GHz,with a quality factor of about 40 and an inductance of over 5nil at 11.3GHz. Simulations based on a compact equivalent circuit model of the inductor and parameter extraction using a characteristic-function approach are carried out,and good agreement with measurements is obtained.

MATLAB-Based Simulation of Buoyancy-Driven Underwater Glider Motion

The mass configuration of the buoyancy-driven underwater glider is decomposed and defined. The coupling between the glider body and its internal masses is addressed using the energy law. A glider motion model is established, and the corresponding simulation program is derived using MATLAB. The characteristics of the glider motion are explored using this program. The simula- tion results show that the basic characteristic of a buoyancy-driven underwater glider is the periodic alternation of downward and upward motions. The glider's spiral motion can be applied to missions in restricted regions. The glider's horizontal velocity, gliding depth and its motion radius in spiral motion can be changed to meet different application purposes by using different glider parameter designs. The simulation also shows that the model is appropriate and the program has strong simulation functions.

A New Fine Damping Method for Solid ESG Rotor

For the electrostatically suspended gyro （ESG） with solid rotor, because the equatorial photoelectric sensor won＇t sense the equatorial marking line and output the correct damping control information when the nutation angle is small, the active damping with equatorial marking line will bring considerable error. The passive damping method by applying strong DC magnetic field requires too much time. So an active damping method by longitude marking lines is proposed to fulfill the fine damping for solid ESG rotor. The shape of rotor marking lines and the principle of fine damping are introduced. The simulation results prove that this fine damping method can effectively solve the problem of damping error introduced by active damping with equatorial marking line. The estimating resuits for damping time indicate that the fine damping time is less than 10 percent of passive damping time.

Special requirements for alumina ceramic of ESG electrode bowl

At present ESG (Electrostatic Suspended Gyro) is the most precise inertia element in the world. The electrode bowl, which has direct effect on the precision of ESG, is a key part to ESG. Through the analysis of the function and characteristic of the electrode bowl in hollow rotor ESG and the present situation of new material development in the world, the alumina ceramic is regarded as the best material for the electrode bowl of hollow rotor ESG. By analyzing the present situation of alumina ceramic in the world, main technique requirements have been put forward for the alumina ceramic of ESG electrode bowl which is also fit for solid rotor ESG.

Novel Implicit Lorentz Force-Type Magnetic Bearing for High-Precision Agile Maneuver of Magnetically Suspended Gyrowheel

The lorentz force-type magnetic bearing(LFTMB)with good linearity is suitable for the high-precision deflection control of the magnetically suspended gyrowheel(MSGW). Two kinds of novel implicit LFTMBs are proposed in allusion to the poor magnetic flux density uniformity of the existing explicit LFTMB. The improvement of uniformity is realized under the paramagnetic contribution of magnetic ring. Their structures are introduced,the mathematical models are established based on the equivalent magnetic circuit method and the magnetic fields are analyzed by the finite element method based on the design parameters. Simulation results indicate that the magnetic flux density uniformity of implicit LFTMBs is superior to the traditional explicit LFTMB. Furthermore,the implicit trapezoid LFTMB with double magnetic circuits is better than that of those with single magnetic circuit,in terms of the magnetic flux density uniformity and the magnetic flux density. The magnetic flux density of implicit trapezoid double magnetic circuits LFTMB is verified by the experiment. The error between the experimental results and the simulation results is within 5%,which shows that the implicit trapezoid double magnetic circuits LFTMB is promising to meet the high-precision agile maneuver requirement of the magnetically suspended gyrowheel.

江苏省血吸虫病监测预警系统的研究 Ⅴ长江水域血吸虫毛蚴感染性的监测

目的建立长江水体血吸虫毛蚴监测方法,监测水体受血吸虫虫卵污染情况,为追踪与控制传染源、切断传播途径及灭螺提供参考依据。方法在长江江苏段选择45个监测点,采用浮瓶-尼龙袋哨螺测定法,每个点投放500只阴性钉螺,于2009年5-9月每月投放1次,每次投放28 h,钉螺收回后置于25℃恒温箱内饲养。首次回收2个月后每月采用群体逸蚴法检测1次钉螺感染性,在末次投放3个月后,采用压碎法解剖全部钉螺,观察钉螺血吸虫感染情况,并调查出现感染螺环境的人畜活动情况。建立江苏省长江水域哨螺监测数据库,绘制哨螺阳性点地理分布图,计算江水中钉螺单位时间被血吸虫毛蚴感染的阳性率。结果 45个点5个月共投放哨螺44 717只,回收43 477只,回收率为97.23%;钉螺逸蚴81 410只次,未发现感染性钉螺;解剖钉螺13 033只,发现5只感染血吸虫,钉螺感染率为0.038%,水体中钉螺感染血吸虫的阳性率为4.11/100万。在45个监测点中检出阳性点5个,阳性点出现率为11.11%;其中哨螺阳性点分布在长江南岸3个、北岸1个、江心洲1个,其阳性点出现率分别为21.43%、5.56%和7.69%,南岸哨螺阳性点出现率是北岸的3.8倍。5个阳性点中有3个为渔船民集散地。结论江苏省长江南岸水域受血吸虫虫卵污染程度高于北岸,渔船民集散地是重要的污染地之一。浮瓶-尼龙螺袋哨螺测定法是监测水体受血吸虫虫卵污染的有效方法。