基于精密扭秤周期法微电量测量的试验研究

本论文利用精密扭秤测量弱力的优越性,以精密扭秤为核心搭建一套微小电量的检测系统,采用动态周期法实现微电量检测。扭秤细杆两端粘贴金属带电小球,微电量小球的精密扭秤受静电场力和扭丝扭力的共同作用下的周期性摆动,通过测量摆动周期得到金属小球的带电量Q。测量系统采用光尺原理,配合使用PSD光位移传感器,最终通过数字存储示波器连接计算机进行数据的自动处理,实现小球微电量的测量。

微电量测量中信号的拾取和放大

本文介绍了静电计级运算放大器在工业微电量测量中的应用,并且给出了实际的电路结构和相关的噪声解决办法。

植物微电量采集系统设计

为更好地保护森林资源,对其生态信息进行规范、有效的监控不可或缺。无线传输可以解决森林环境信息采集过程中有线电路铺设成本高、易受干扰的缺点,是一种理想的监测信号传输模式。但无线传输设备的供电问题,却是其实际使用面临的重要问题。通过对不同植物类型、不同采集方式的分析,设计研究了植物微电量采集系统。设计超级电容将植物微电量蓄积,并利用DC-DC升压电路对微电量进行升压处理,最后采用充电管理电路对电池的充放电进行管理。该能量收集系统实现了使用植物微电量为无线设备的电池供电。最终做到无需外部供电设备即可利用现有的无线传输网络发送环境信息有效提高森林监测的经济性及实用性。

利用精密扭秤测量微小电量

充分利用精密扭秤对弱力的高灵敏度,结合机械共振放大力的效应原理、电磁阻尼原理和光杠杆原理进行改装,可测得带电体所受的弱电场力,进而求得微小电量。初步实验结果证实该方法的可行性。

恒电量微扰法研究在含Cl^-介质Ce^(3+)对航空铝材的缓蚀作用

本文用恒电量微扰法研究了Ce3+对铝合金在0．1mol·L-1NaCl介质中的缓蚀机理及抗孔蚀性。结果表明：铝合金孔蚀诱导过程及其表面形成林转化膜过程具有相同的电化学模式，电化学腐蚀速度控制步骤取决于钝化膜（转化膜）／溶液界面过程。Ce3+对铝合金孔蚀的诱导期和发展期均有抑制作用，形成铈转化膜后，铝基表面阻抗大大提高，耐孔蚀性增强。

恒电量微扰法研究在含CI^-介质中Ce^(3+)对航空铝材的缓蚀作用

本文用恒电量微扰法研究了C33+对铝合金在0.1mol·1-1NaCI介质中的缓蚀机理及抗孔蚀性。结果表明：铝合金孔蚀诱导过程及其表面形成铈转化膜过程具有相同的电化学模式，电化学腐蚀速度控制步骤取决于钝化膜（转化膜）／溶液界面过程。Ce3+对铝金孔蚀的诱导期和发展期均有抑制作用，形成铈转化膜后，铝基表面阻抗大大提高，耐孔蚀性增强。

从恒电量微扰下的ΔE_t～t曲线求取塔菲常数

本工作采用恒电量技术,分析恒电量微扰下的△E～t衰减曲线以获得塔菲尔斜率。这种断电的松弛方法不受溶液电阻的影响,因而特别适用于高阻介质和涂装金属体系。该方法以电化学基本方程为基础,结合恒电量微扰技术原理。使用基尔霍夫和结点电流公式列出微分方程组,然后采用四阶龙格——库塔法解微分方程组。可将△E值缩小到±10mV的范围。对几个实验体系所进行的试验验证了本方法的可行性。

微弱电信号检测技术

主要介绍微弱电压信号和电流产生的主要因素及其测量方法，指出在精密测量过程中需要注意的一些问题：如接地、屏蔽和抗干扰等。

A Solenoid-Type Inductor Fabricated by MEMS Technique

A solenoid-type inductor for high frequency application is realized using a micro-electro-mechanical systems (MEMS) technique.In order to achieve a high inductance value and Q-factor,UV-LIGA,dry etching technique,fine polishing and electroplating technique are adopted.The dimensions of the inductor are 1500μm×900μm×70μm,having 41 turns with a coil width of 20μm separated by 20μm spaces and a high aspect ratio of 3.5∶1.The maximum measured inductance of the inductor is 6.17nH with a Q-factor of about 6.

Beryllium-distribution in metallic glass matrix composite containing beryllium

The morphologies, sizes, compositions and volume fractions of dendritic phases in in situ Ti-based metallic glass matrix composites （MGMCs） containing beryllium （Be） with the nominal composition of Tia7Zr19Cu5V12Be17 （mole fraction, %） were investigated using XRD, SEM, EBSD, TEM, EDS and three-dimensional reconstruction method. Moreover, visualized at the nanoscale, Be distribution is confirmed to be only present in the matrix using scanning transmission electron microscopy-electron energy loss spectroscopy （STEM-EELS）. Based on these findings, it has been obtained that the accurate chemical compositions are Wi28.3Zr19.7Cu8V6.4Be37.6 （mole fraction, %） for glass matrix and Wi62.nZr18.aCu2.6V16.6 （mole fraction, %） for the dendritic phases, and the volume fractions are 38.5% and 61.5%, respectively. It is believed that the results are of particular importance for the designing of Be-containing MGMCs.

一宗侵权案的启迪

我市某电子企业属于高新科技产业。该企业与北京某大学签订了专利技术开发协议。近年购买了该大学的技术专利并组织技术力量攻关,成功地开发了微电量变迭器和无功自助补偿器两种电子新产品。经有关部门技术鉴定,两种产品均被列为国家级新产品,在全市电子行业中一枝独秀,有较好的发展前景。 然而,由于该企业缺乏必要的内部控制制度,

Application of radioanalysis to the transport of micro-constituents by diffusion

Predictions on the leaching behaviour of microconstituents from dumped, stored, or immobilised wastes are based on estimates of the effective diffusion coefficients involved, which usually range from ～10^-6 to ～10-12 cm^2.s^- 1. Radioanalysis, especially radiotracer procedures, can be applied to determine these parameters on small (field) samples of granular material and test specimens of immobilised wastes. A summary of standard experiments for both types of material under non-steady state and steady state conditions is

Effects of Reducing Mn^(2+),Cu^(2+) and Zn^(2+) Concentrations in Nutrient Solution on SOD Activity in Grafted Cucumber Seedling Leaves Under Cold Stress

[Objective] The research aimed to study the effects of reducing the concentrations of Mn2＋, Cu2＋ or Zn2＋ in nutrient solution on the contents of Mn, Cu and Zn of grafted cucumber leaves as well as on the SOD and isozymes activities and the rate of electrolytic leakage under cold stress. [Method] Nutrient solution containing low concentrations of Mn2＋, Cu2＋ or Zn2＋ were used for cultivating the grafted cucumber seedlings for the cold treatment. [Result] The results indicated that reducing the concentrations of Mn2＋, Cu2＋ or Zn2＋ in nutrient solution had declined the SOD activities in grafted cucumber leaves and increased the rates of electrolytic leakage. Mn2＋ had shown the maximum influences, followed by Cu2＋, and Zn2＋ had shown the minimum influences. [Conclusion] Cold resistance of cucumber can be improved by changing the contents of Mn2＋, Cu2＋ or Zn2＋ in nutrient solution.

Fabricating a Micro Electromagnetic Actuator with High Energy Density

This paper introduces a new technology to fabricate a micro electromagnetic actuator with high energy density without an enclosed magnetic circuit. This technology includes fabricating multi-turns planar micro coils and fabricating the thick magnetic （NiFe） core on the silicon wafer. The multi-turns planar micro coils are fabricated by the electroplating method from the surface along the line and by dynamically controlling the current density of the copper electrolytes. In order to fabricate thick NiFe plating,the adhesion properties between the NiFe plating and the silicon substrates are improved by changing the surface roughness of the silicon substrates and increasing the thickness of the seed layer. Furthermore,the micro electromagnetic actuator is tested and the energy density of the actuator is evaluated by force testing. The experiments show that the microactuator is efficient in producing high magnetic energy density and high magnetic force.

Comparison and Analysis of Two Microwave Equivalent-Circuit Models for Resonant Tunneling Diode

The distinction between two microwave equivalent-circuit models,quasi Esaki tunneling model (QETM) and quantum well injection transit model (QWITM),for the resonant tunneling diode (RTD) is discussed in details,and two groups of circuit parameters are extracted from experiment data by the least square fit method.Both theory analysis and the comparison of fit results demonstrate that QWITM is much more precise than QETM.In addition,the rationality of QWITM circuit's parameters confirms it too.On this basis,the resistive frequency is calculated,whose influence factors and improvement method are simply discussed as well.

Quankum Effects of a Dissipative Mesoscopic Circuit with Mutual Inductance

We study the quantum fluctuations of the charge and current of two L-C dissipative mesoscopic circuit with the mutual inductance in the vacuum state.Our results show that the system state will evolve to a squeezed coherent state under the effect of external source.We find that the squeezing amplitude parameter is relative to the parameters of circuit and the mutual-inductance coefficient in the existence of dissipation.When the circuit has no dissipation or there is complete coupling between two meshes,the squeezing amplitude parameter only depends on the capacitance's ratio.

Microstructure and mechanical properties of Al-Zn-Cu-Mg-Sc-Zr alloy after retrogression and re-aging treatments

The mechanical properties and stress corrosion cracking （SCC） resistance of an Al-Zn-Cu-Mg-Sc-Zr alloy under different aging conditions were investigated. The dependence of microstrueture and mechanical properties on aging parameters was evaluated by tensile test, hardness test and conductivity measurement. The results show that for the alloys with retrogression and re-aging treatment （RRA）, the conductivity increases with the retrogression time and temperature, while the tensile strength decreases. The transmission electron microscopy （TEM） results show that the precipitates η（MgZn2） at grain boundary aggregate apparently with retrogression time and the precipitates inside the matrix exhibit the similar distribution to T6 temper, which comprises fine GP zones, large η＇（MgZn2）and η（MgZn2） phases. According to the mechanical properties and microstructure observations, the optimal RRA regime is recommended to be 120℃, 24h ＋ 180 ℃, 30 min ＋ 120 ℃, 24 h. The strength level of the alloy after the optimum RRA treatment is similar to that in T6 condition and the SCC resistance is improved obviously in contrast to T6 condition.

Multiple Entropy Measures for Multi-particle Pure Quantum State

We propose to use a set of averaged entropies, the multiple entropy measures (MEMS), to partiallyquantify quantum entanglement of multipartite quantum state.The MEMS is vector-like with m = [N/2] components:[S_1, S_2,..., S_m], and the i-th component S_i is the geometric mean of i-qubits partial entropy of the system.The S_imeasures how strong an arbitrary i qubits from the system are correlated with the rest of the system.It satisfies theconditions for a good entanglement measure.We have analyzed the entanglement properties of the GHZ-state, theW-states, and cluster-states under MEMS.

Effects of Yb addition on microstructures and mechanical properties of 2519A aluminum alloy plate

The effects of Yb content on the microstructures and mechanical properties of 2519A aluminum alloy plate were investigated by means of tensile test,optical microscopy,transmission electron microscopy,scanning electron microscopy and X-ray diffractometer.The results show that addition of 0.17% (mass fraction) Yb increases the density of θ' particles of the 2519A alloy plate and reduces the coarsening speed rate of θ' phase at 300 ℃.Therefore,tensile strength is enhanced from 483.2 MPa to 501.0 MPa at room temperature and is improved from 139.5 MPa to 169.4 MPa at 300 ℃.The results also show that with the addition of 0.30% (mass fraction) Yb,the mechanical properties increase at 300 ℃ and decrease at room temperature.With Yb additions,the Al7.4Cu9.6Yb2 phase is found whilst the segregated phases of as-cast alloys along grain boundaries become discontinuous,thin and spheroidized.

Ultrasonic power features of wire bonding and thermosonic flip chip bonding in microelectronics packaging

The driving voltage and current signals of piezoceramic transducer (PZT) were measured directly by designing circuits from ultrasonic generator and using a data acquisition software system. The input impedance and power of PZT were investigated by using root mean square (RMS) calculation. The vibration driven by high frequency was tested by laser Doppler vibrometer (PSV-400-M2). And the thermosonic bonding features were observed by scanning electron microscope (JSM-6360LV). The results show that the input power of bonding is lower than that of no load. The input impedance of bonding is greater than that of no load. Nonlinear phase, plastic flow and expansion period, and strengthening bonding process are shown in the impedance and power curves. The ultrasonic power is in direct proportion to the vibration displacement driven by the power, and greater displacements driven by high power (>5 W) result in welding failure phenomena, such as crack, break, and peeling off in wedge bonding. For thermosonic flip chip bonding, the high power decreases position precision of bonding or results in slippage and rotation phenomena of bumps. To improve reliability and precision of thermosonic bonding, the low ultrasonic power (about 1-5 W) should be chosen.