聚甲基丙烯酸甲酯与SiO2的复合研究

将正硅酸乙酯和乙醇的混合溶液加入到乙醇、水和氨水的混合溶液中,水解制备出单分散SiO2的乙醇分散液,然后分离出SiO2纳米粒子.接着利用硅烷偶联剂KH-570对SiO2纳米粒子进行表面改性以改善其亲油性.通过分散性试验,发现SiO2纳米粒子的亲水性明显降低而亲油性明显增加,证明硅烷偶联剂KH-570已经成功地接枝到纳米SiO2颗粒表面.采用超声波分散方法将其分散在含有甲基丙烯酸甲酯的乙酸乙酯和苯组成的混合溶液中,采用原位聚合法制备出PMMA/SiO2纳米复合材料.利用DSC、TGA和FTIR实验方法及溶解性实验对PMMA/SiO2纳米复合材料进行了测试.试验结果表明,SiO2纳米粒子在复合材料中起着物理交联点和化学交联点的作用.     

宽脉冲光子计数偏振激光雷达探测浅水层研究（特邀）

由于受激光脉冲宽度的限制,传统激光雷达无法实现几十厘米的浅水层测量。设计了一个双Gm-APD光子计数偏振激光雷达系统,采用宽脉冲获取薄浅水层的高精度距离像。浅水层的表面光滑,能够保偏;底面粗糙,将发生退偏。根据该偏振现象,通过发射水平线偏振光,接收系统中采用一个偏振分光棱镜将前后表面信号光分离,然后分别被两个Gm-APD探测。该系统不受信号光的脉冲宽度限制,并充分利用Gm-APD的死时间机制,针对超薄浅水层实现三维深度测量。利用基于穆勒矩阵和斯托克斯参量表示的偏振传输原理,理论分析了双Gm-APD偏振激光雷达的分光原理。采用信号复原质心算法抑制距离漂移误差获取高精度距离信息。对于深度从4.5cm变化到8 cm渐变的薄浅水层,底面覆盖了黑、白沙子,探测距离为5 m,在实验上采用6 ns激光脉冲获取了薄浅水层的高精度距离像,测距精度为0.8 cm,有效验证了方案的可行性。该方案能够为机载海洋测绘激光雷达的浅水层测量提供一定借鉴。     

复方苦槿霜抗真菌作用的实验研究

目的 :探讨和验证自拟中药方剂复方苦槿霜治疗皮肤浅部真菌病的抑菌试验及药理药效。方法 :将 5 %、10 %、2 0 %复方苦槿霜对常见皮肤致病真菌进行抑菌试验及药效学实验。结果 :10 %、2 0 %复方苦槿霜抑菌效果相当 ,明显优于 5 %复方苦槿霜的抑菌效果 (P <0 .0 5 ) ,10 %、2 0 %复方苦槿霜抑菌效果与达克宁相当 (P >0 .0 5 ) ,并对皮肤常见致病真菌都有抑制作用。药效学试验结果 :复方苦槿霜临床日用量是安全的。无皮肤刺激及过敏反应。结论 :本研究为临床应用纯中药制剂治疗皮肤浅部真菌病提供了科学依据 ,证实了复方苦槿霜的科学性及可行性。     

Analysis of the effects of water on the ACTS propagation terminal antenna

The NASA advanced communications technology satellite (ACTS) propagation experiment was designed to observe the attenuation produced by rain on Earth-satellite paths operating in the Ka-band. Unwanted effects of water on the antenna reflector surface were noted. Wet-antenna attenuation could be attributed to the combined effect of a water layer on the reflector surface and water wetting the feed window surface. A model was developed to calculate the antenna reflector and feed surface water layer thickness values as a function of position on each surface. The thickness values were used to calculate the additional attenuation produced by the water layers as a function of rain rate on the antenna. The wet-antenna-attenuation prediction model was verified by sprayer tests. The goal of the ACTS propagation experiment was to obtain path attenuation statistics, statistics that represent the effects of rain on the Earth-satellite path but not on the antenna itself. The wet-antenna attenuation prediction model was used to remove the effects of water on the antenna from the combined antenna-plus-path attenuation statistics produced by the experiment. The overall efficacy of the model was demonstrated by comparing the corrected path loss statistics from two ACTS propagation experiment sites with earlier COMSTAR path loss measurements made at or near those sites. The empirical distribution functions from both the ACTS and COMSTAR experiments were identical within the expected uncertainty of an empirical annual distribution of attenuation by rain.     

渐变结构TE11^0—TE11^{}模式变换器

本文介绍了一种新的渐变截面ＴＥ１１－ＴＥ１１模式变换器，并采用有限元法及耦合模理论对变换器进行了理论分析，实验测试表明在对接收极化在１２．５－１８．０ＧＨｚ的频率范围内，变换器的电压驻波比小于１．２，而且测试曲线与计算曲线的有较好的吻合。     

三维LDV/APV系统研究细水雾与射流卷吸现象

利用三维激光多普勒测速计和自适性相位多普勒速度计系统（三维ＬＤＶ／ＡＰＶ系统）,通过观察和测量劝水雾被射流卷吸的现象,获取了细水雾的平均速度、平均粒径和雾通量等特性参数,深化认识细水雾被射流卷吸的机理,为下一步进行细水雾被火焰卷吸现象的实验研究打下了良好的基础。     

激光全息照相实验技巧（三）

本文结合我们实验中的经验，总结了若干提高彩虹全息图质量的技巧。     

复方苦槿霜的皮肤毒理学实验研究

目的：评价复方苦槿霜局部用药的安全性。方法：皮肤刺激试验：40％、80％复方苦槿霜分别涂于家兔完整皮肤和破损皮肤;皮肤过敏试验：40％复方苦槿霜反复接触豚鼠背部皮肤。结果：40％、80％复方苦槿霜外用对动物无局部刺激作用和过敏反应。结论：复方苦槿霜外用是安全的。     

Equations for Calculating the Dielectric Constant of Saline Water (Correspondence)

The dielectric constant of saline water may be represented by an equation of the Debye form. Equations for the parameters in the Debye expression are given as functions of the water temperature and salinity.     

Electron beam induced current (EBIC) as a function of the angle of incidence of the electron beam in a scanning electron microscope (SEM)

The paper presents an analysis of the Electron Beam Induced Current as a function of the angle of incidence of an electron beam. A SEM experiment under steady-state conditions for a silicon diode structure has been performed. Two simple theoretical models have been considered.     

细水雾与固体木垛火相互作用的红外热像研究

利用TVS-2000ST型热像系统,以热电偶为辅助观察和测量细水雾与火焰相互作用前后火焰热场的结构的变化,分别对细水雾与不同尺寸和功率的固体木垛火的相互作用进行了实验研究,为进一步认识细水雾与固体扩散火焰相互作用的机理提供了简捷可靠的实验手段.     

Monitoring of melting refreezing cycles of snow with microwave radiometers: the Microwave Alpine Snow Melting Experiment (MASMEx 2002-2003)

A study of the melting cycle of snow was carried out by using ground-based microwave radiometers, which operated continuously 24 h/day from late March to mid-May in 2002 and from mid-February to early May in 2003. The experiment took place on the eastern Italian Alps and included micrometeorological and conventional snow measurements as well. The measurements confirmed the high sensitivity of microwave emission at 19 and 37 GHz to the melting-refreezing cycles of snow. Moreover, micrometeorological data made it possible to simulate snow density, temperature, and liquid water content through a hydrological snowpack model and provided additional insight into these processes. Simulations obtained with a two-layer electromagnetic model based on the strong fluctuation theory and driven by the output of the hydrological snowpack model were consistent with experimental data and allowed interpretation of both variation in microwave emission during the melting and refreezing phases and in discerning the contributions of the upper and lower layers of snow as well as of the underlying ground surface.     

Electron-bombarded semiconductor (EBS) switch

The swiching of an electron-bombarded semiconductor diode by means of forward bias is demonstrated. With development, such switches may be advantageous for high-power, high-frequency matrix switching. A theoretical argument indicates that isolation similar to that of optoelectronic diode switches without gain can be obtained. Isolation over 30 dB is observed in a simple experiment.     

细水雾发生及抑制液体火焰的实验研究

本文设计加工了细水雾发生器，并且应用三维LDV／APV(Adaptive Phase/Doppler Velocimeter)系统对其产生的细水雾雾场特性参数做了有效的测量，并在此基础上进行了细水雾抑制液体火有效性的模拟实验．利用热像仪、热电偶和摄像机等仪器研究了这种细水雾抑制熄灭煤油火和酒精火的过程。实验结果表明细水雾技术具有应用在灭火系统上的可行性，并具有优越的特点。     

Electron surface trapping effects on the switching voltage of metal-insulator (tunnel)-Si(n)-Si(p+) devices

Using double-delay pulse method for investigation of the dynamic characteristics of MIS switching devices, we have observed an abnormal dependence of the switching voltage on the pulse separation time in AuSiO₂ (tunnel)-Si(n)-Si(p⁺) diodes. This abnormal dependence may be attributed to the electron trapping and detrapping in the surface states at the SiSiO₂ interface. A simple model of the surface discrete traps is given and the calculation is in good agreement with experiment.     

Analysis and Experiment Concerning the Cutoff Frequencies of Rectangular Striplines (Short Paper)

The cutoff frequency of the first higher order mode in a rectangular stripline is determined by two disparate techniques and compared to published results. Results from a novel experiment verify the cutoff frequency predictions. Furthermore, a nomenclature scheme for uniquely identifying rectangular stripline modes is offered.     

Cloud Statistics Measured With the Infrared Cloud Imager (ICI)

The Infrared Cloud Imager (ICI) is a ground-based thermal infrared imaging system that measures spatial cloud statistics with a 320$,times,$240-pixel uncooled microbolometer detector array. Clouds are identified from the residual radiance that remains after water vapor emission is removed from radiometrically calibrated sky images (the water vapor correction relies on measurements of precipitable water vapor and near-surface air temperature). Cloud amount, the percentage of an ICI image containing clouds, is presented for data from Atmospheric Radiation Measurement (ARM) sites at Barrow, AK in February–April 2002, Lamont, OK in February–April 2003, and Barrow, AK in March–April 2004. In Oklahoma, the percent cloud cover determined from full ICI images was slightly higher than that found from a single-pixel time series, suggesting that cloudiness may be under sampled by vertically viewing lidars or radars under highly variable conditions. Full-image and single-pixel statistics agreed more closely for Arctic clouds, which tend to be uniform for long periods of time. Good agreement is found in comparing cloud amount from ICI and active remote sensors during day and night, but much worse agreement is found between ICI and the ARM Whole Sky Imager during nighttime relative to daytime, indicating the importance of the diurnally consistent ICI measurements.     

Microstrip Varactor-Tuned Millimeter-Wave Transmitter (Letters)

A 60-GHz varactor-tuned microstrip oscillator intended for use in a millimeter-wave radio relay experiment has been designed and tested. The output power of the transmitter is 110 /spl plusmn/ 15 mW from 58.5 to 60.1 GHz. The oscillator can be frequency-shift keyed (FSK) at a rate up to 200 Mbit/s. The rms FM noise of about 400 Hz/(kHz)/sup 1/2/ meets the required system specifications.     

工业自动化网络虚拟实验平台的研究与实现

以"工业自动化网络"课程的实验为背景,基于LonWorks总线及TCP/IP技术,探讨了开发网络远程虚拟实验平台的相关技术.在此基础上,实现了工业自动化网络课程的相关远程实验,并对水箱液位自动控制系统的远程试验进行了模拟实现,为网络虚拟试验室的具体实现奠定了基础.试验证明该系统基本达到了远程实验的目的.     

Tunable Superparamagnetic Ring (tSPRing) for Droplet Manipulation

The manipulation of droplets via a magnetic field forms the basis of a fascinating technology that is currently in development. Often, the movement of droplets with magnets involves adding magnetic particles in or around the droplet; alternatively, magneto responsive surfaces may also be used. This work, presents and characterizes experimentally the formation and properties of a tunable superparamagnetic ring (tSPRing), which precisely adjusts itself around a water droplet, due to liquid–liquid interaction, and enables the physical manipulation of droplets. The ring is made of an oil-based ferrofluid, a stable suspension of ferromagnetic particles in an oily phase. It appears spontaneously due to the oil–water interfacial interaction under the influence of a magnetic field. The ferrofluid–water interaction resembles a cupcake assembly, with the surrounding ring only at the base of the droplet. The ring is analogous to a soft matter ring magnet, showing dipole repulsive forces, which stabilizes the droplets on a surface. It enables robust, controllable, and programmable manipulation of enclosed water droplets. This work opens the door to new applications in open surface upside or upside-down microfluidics and lays the groundwork for new studies on tunable interfaces between two immiscible liquids.