L波段射频加速器电子束微脉冲诊断

 利用切伦柯夫辐射的瞬时发光机理,把相对论电子束打在熔石英靶片上转化为可见光,再用皮秒扫描相机进行测量,就可得到射频直线加速器皮秒电子束微脉冲的峰值电流及微脉冲束团。采用该方法,对L波段射频直线加速器的电子束微脉冲宽度和束团结构进行了诊断。由此构建了一套加速器电子束微脉冲的在线测量系统,该系统对调整加速器工作状态、提高束流品质使之适应自由电子激光要求起到了重要作用。     

用于种子注入的微型二极管泵浦激光器

设计了一种用于种子注入的微型二极管泵浦激光器,并从LD泵浦固体激光器优化设计原则出发,对种子激光器的增益介质、耦合系统、谐振腔进行了优化设计.实验研究表明,该激光器运转稳定,输出光束质量高,光束发散角小,输出功率可达80 mW,可满足种子激光的要求.     

A boosted voltage generator for low-voltage DRAMs

This paper proposes a new two-stage two-phase VPP charge pump configured in such a manner that the body effect and the threshold voltage loss are eliminated. The newly proposed circuit is fabricated using 0.18 μm triple-well CMOS process and the measurement result shows that the VPP level tracks 3VDD when VDD is above the threshold voltage.     

微小缺陷的非线性超声检测及其成像技术

采用通用超声检测设备并结合高通滤波技术获取了非线性超声的高次谐波信号,并将其用于薄板点焊焊核的微小缺陷检测及焊核的超声C扫描成像中。较之传统超声检测方法,采用非线性高次谐波检测薄板点焊焊核缺陷具有更高的时域分辨率及缺陷敏感度,能够更加准确的确定内部缺陷的位置及尺寸。此外,本研究还采用非线性高次谐波对薄板焊核进行超声成像分析,获得了清晰准确的焊核结构图像。非线性超声检测技术具有更高的检测效力,能够显著拓展检测系统的检测能力。     

基于HL7的移动式微型临床实验室Mini Lis接口设计

由于移动式微型临床实验室集成了多种不同的医疗仪器,导致各应用系统之间难以实现数据信息交换与共享等问题。因此本文通过对微型临床实验室信息管理系统(Mini LIS)进行需求分析,研究了Mini LIS的接口设计。采用医疗信息行业国际前沿的HL7标准,结合XML编码方式,使用DOM技术实现对基于XML模式的HL7消息进行构建和解析,运用MQSeries信息传输系统作为中间件。实现了各仪器应用系统之间数据格式的统一,以及数据信息的交换与共享,解决了各应用系统间的通讯难题,成功集成了多种仪器,并在实际中取得了良好的应用效果。     

Physical foundations for high-temperature electron-beam modification of ceramics

We consider the phenomenon of radiation-accelerated high-temperature mass transfer (RAHTMT) in heterogeneous ion structures under the influence of powerful electron beams. We present a theoretical basis for a surface-recombination mechanism for RAHTMT. The basis for the mechanism is the notion of volume-inhomogeneous dissipation of radiation energy in heterogeneous structures and thermal-diffusion stimulation of mass transfer. We show that high-temperature radiation annealing is an efficient technological method for obtaining ceramics with different and unique properties. Methods of radiation modification have been used to obtain corundum—zircon ceramics with world-class properties. Tomsk Polytechnic University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 176–192, November, 1996.     

Luminescent compositions for creation of low-voltage cathode luminophores

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 5, pp. 855–857, November, 1991.     

A low-voltage decay time analyzer for monitoring ionizers

This paper presents a development of a low-voltage decay time analyzer to replace the charged plate monitor which works at the high-voltage level. The proposed low-voltage decay time analyzer is based on the measurement of the induced charges on a conductive plate via an ultra-high input impedance amplifier. A microcontroller with an Ethernet module is the central processing to control, calculate the decay time, and enable network communications. The test results show that the analyzed decay times correlate to the standard test method.     

Computer-generated hologram fabricated by electron-beam lithography for noise reduction

A Lohmann-type computer-generated hologram (CGH) is fabricated using an electron-beam lithographic system. A high-resolution groove width of 0.2 μm is attained in relief gratings by changing the e-beam exposures. A diffraction efficiency close to ∼30.4% is obtained by using resist-on-silicon recording materials and cell-structural apertures in a CGH. The reconstructed images exhibit fewer phase noises owing to the incorporation of a non-overflow cell structure into a CGH. The CGH is designed for reconstruction-noise reduction by using an iterative error-reduction algorithm. The designed CGH exhibits fewer reconstruction noises such that the performance function in the convergence is smaller by a factor of 1/3 than that in the first iteration. Experiments demonstrating the performance of CGHs obtained by electron-beam lithography are presented.     

实现微位移测量的非本征法布里-珀罗干涉型光纤传感器

从光纤耦合和多光束干涉的原理出发,建立了非本征型法布里_珀罗干涉仪光纤传感器的理论模型,得到了用光谱法进行绝对距离测量的公式。设计出了传感器探头的结构,并搭建了系统。用LED作为宽带光源所得到的反射光谱可用于实际样品的微位移测量。实验结果表明,该传感器理论模型的数值模拟结果与实验结果是一致的。对实验数据进行了误差分析,所得到的测量精度可达到1μm。     

微小层片型缺陷的超声非线性区域检测技术*

针对微小层片型缺陷的超声检测效率低、检测能力弱、易受主客观因素干扰的问题,提出弹簧扁钢中微小层片型缺陷的非线性超声区域检测技术。首先,优化探头夹持装置并提出区域检测方法,提取稳定可靠的检测信号;其次,提出相对非线性系数均值及波动系数表征缺陷分布;最后,基于斯皮尔曼次序相关系数分析扁钢各类缺陷与非线性超声系数均值的相关性。研究结果显示:两种非线性超声特征参数中的波动系数具有更高的缺陷敏感度,可表征扁钢中缺陷分布;波动系数与扁钢中微小层片型缺陷的相关系数比与体积型缺陷的相关性系数大得多,特别适用于微小层片型缺陷的检测。     

Proximity-effect induced density limitations for electron-beam patterned planar photonic nanomaterials

Patterning of deeply subwavelength artificial nanomaterials, e.g. photonic crystals or plasmonic metamaterials, for the visible or near-infrared optical spectrum is a challenging task. Electron-beam lithography is often the method of choice thanks to its combination of flexibility, accuracy and availability in many research laboratories. In this article an analytical model for large and dense arrays of photonic nanostructures is presented which allows to predict the maximum fill ratio (radius divided by nearest neighbor distance) before the onset of resist loss between the individual elements. The model includes geometrical parameters of the design (lattice constant, lattice symmetry), the resist contrast and proximity parameters (beam broadening, backscatter range, backscatter efficiency). It is shown that the resist contrast has a significant impact on the achievable maximum fill ratio even for large nearest neighbor distances and that the beam broadening is of paramount importance. The background energy level which is determined by the backscatter efficiency and the lattice symmetry is shown to have a weaker influence on the maximum fill ratio. The derived model can be used as a guideline in the project planning stage to predict achievable fill ratios at a planned lattice constant and consequently an assessment whether a desired functionality at a certain wavelength is possible or not.     

Prospects of developing multibeam systems for low-voltage electron lithography

The prospects of developing tiny multibeam systems for electron lithography have been considered. Designs of tiny basic elements of electron-optical systems, including a magnetic lens with an open magnetic circuit and a lens with aligned axially symmetric fields (whose magnetic circuit simultaneously plays the role of electrodes of an electrostatic lens), are represented, as well as their analysis. The results of the investigation of high-speed one-turn deflection systems without or with a core and the analysis of a stigmator are reported. Radically new approaches to design of tiny electron-optical systems have been considered, which make it possible to increase the efficiency of electron beam formation and pass to micro-and nanotechnological design of vacuum microsystems.     

Micromachined silicon lenses for terahertz applications

Silicon microlenses are a very important tool for coupling terahertz (THz) radiation into antennas and detectors in integrated circuits. They can be used in a large array structures at this frequency range reducing considerably the crosstalk between the pixels. Drops of photoresist have been deposited and their shape transferred into the silicon by means of a Reactive Ion Etching (RIE) process. Large silicon lenses with a few mm diameter (between 1.5 and 4.5 mm) and hundreds of μm height (between 50 and 350 μm) have been fabricated. The surface of such lenses has been characterized using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM), resulting in a surface roughness of about ∼3 μm, good enough for any THz application. The beam profile at the focal plane of such lenses has been measured at a wavelength of 10.6 μm using a tomographic knife-edge technique and a CO₂ laser.     

Single-lens equivalent systems for Grin lenses

In this paper, one simple single-lens optical systems equivalent to Grin lens of various lengths, which are immersed in either homogeneous or inhomogeneous medium, are proposed. Basing on this equivalent system, the imaging properties of Grin lens rod in paraxial approximation have been thoroughly studied. The proposed plain optical system will lead to a straightforward optical analysis of complex optoelectronics systems employing Grin lens rod.     

Wet-etched diffractive lenses for hard X-rays

A method for the fabrication of linear transmission Fresnel zone plates for X-rays in the 8-15 keV photon energy range is presented. The diffractive elements are generated by electron-beam lithography and chemical wet etching of (110)-oriented silicon membrane substrates. Diffractive structures with aspect ratios of more than 30 for 300 nm-wide structures were obtained. The diffraction efficiency of such a lens was measured for 13.3 keV radiation to be 20%.