Quantitative depth profiling of deuterium up to very large depths

Quantitative depth profiles of deuterium up to very large depths are achieved from the energy spectra of protons created by the D(³He,p)α nuclear reaction at incident energies up to 6 MeV. The advantages of this method compared to the more often applied resonance method are discussed. For light target materials the achievable depth resolution is mainly limited by geometrical spread due to the finite size of the detector aperture, while for heavy materials the resolution is mainly limited by multiple small-angle scattering. A reasonable depth resolution throughout the whole analyzed depth can be obtained by using several different incident energies. Depth profiling up to 38 μm is demonstrated for a-C:D layers deposited on the limiter of Tore Supra, and up to 7.5 μm in tungsten coatings from the divertor of ASDEX Upgrade.     

Discriminative detection of deposited radon daughters on CR-39 track detectors using TRIAC II code

A method for detecting deposited ²¹⁸Po and ²¹⁴Po by a spectrometric study of CR-39 solid state nuclear track detectors is described. The method is based on the application of software imposed selection criteria, concerning the geometrical and optical properties of the tracks, which correspond to tracks created by alpha particles of specific energy falling on the detector at given angles of incidence. The selection criteria were based on a preliminary study of tracks’ parameters (major and minor axes and mean value of brightness), using the TRIAC II code. Since no linear relation was found between the energy and the geometric characteristics of the tracks (major and minor axes), we resorted to the use of an additional parameter in order to classify the tracks according to the particles’ energy. Since the brightness of tracks is associated with the tracks’ depth, the mean value of brightness was chosen as the parameter of choice. To reduce the energy of the particles, which are emitted by deposited ²¹⁸Po and ²¹⁴Po into a quantifiable range, the detectors were covered with an aluminum absorber material. In this way, the discrimination of radon’s daughters was finally accomplished by properly selecting amongst all registered tracks. This method could be applied as a low cost tool for the study of the radon’s daughters behavior in air.     

Elemental analysis of light constituents in thin plastic films

Experiments with 1-3 MeV ⁴He beams and 2.2-3.2 MeV proton beams have been performed in order to develop a precise and highly sensitive method for the detection and analysis of light elements in threat or drug materials using simultaneously the RBS and ERDA techniques. Commercially available plastic films have been used as samples. The 1 MeV ⁴He beam has been found to be inadequate owing to the rapid destruction of the targets. Best results have been obtained using proton beams with energies higher than 3 MeV. For 3.2 MeV proton beams, ERDA has been used for the analysis of the hydrogen constituent.     

一种基于LPC2102芯片的倍频器设计方案

设计用LPC2102实现倍频的硬软件,并通过Proteus进行仿真验证。结果表明：通过改变倍频数能够方便地实现不同倍频数的倍频功能。将仿真结果和理论计算的倍频最大输入频率进行对比。使用定时器T0的捕获功能实现对输入信号周期的测量,使用定时器T1的匹配功能产生倍频后的输出信号。通过将输入信号每2个上升沿为一组进行分组,测定输入信号周期只需1个周期。每组中在第二个上升沿中断中复位匹配定时器来消除误差累积,实现输入、输出信号同步。     

智能电能表现场校验仪的开发与设计

介绍了CP2102接口技术和智能电能表现校仪的开发。结合PDA（个人数字助理）、计算机及无线通信技术，使用Delphi、EVC开发工具，在Oracle8i开发的关系型数据库基础上。设计开发了一种电能表现场校验与管理智能系统，实现了电力校表的无纸化工作和智能化管理。     

灰分分布规律研究

介绍了一种计算选煤产品灰分的方法,根据影响产品灰分的因素,建立多元线性回归方程,使产品灰分的确定快捷、准确。该计算方法为产品灰分的确定提供理论依据,为浮沉·试验中累计灰分的确定提供可行方法,在实践和理论上均具有重大意义。     

USB、RS232/RS422接口转换电路的设计

由于USB接口正逐步替代传统的RS232接口成为PC机的标准接口,USB接口转换电路的设计就很有必要。采用Silicon公司高集成度的USB-UART桥接器件CP2102,辅以简单的外部电路,实现了RS232/RS422接口与USB接口转换电路的设计。其中在详细介绍CP2102结构和特性的基础上,给出了接口转换的硬件电路图,最后简单介绍了转换器的工作原理。     

基于CP2102高速USB2.0-CAN适配卡的设计

基于桥接芯片CP2102,设计了USB2.0-CAN的适配卡.系统采用USB和CAN接收中断、通信同步的握手协议等方式,解决了USB的高速率和CAN的低速率、USB的大数据包与CAN的小数据包之间的矛盾,实现了USB数据与CAN数据之间的协议转换和转发.     

Analysis of C, N and O in aerosol collected on an organic backing using internal blank measurements and variable beam size

A method with low MDL (minimum detection limit) was developed for analysis of carbon (C), nitrogen (N) and oxygen (O) in aerosol samples collected on an organic backing. An accelerator-produced beam of protons interacting with the sample and the detection of elastically scattered protons (PESA; particle elastic scattering analysis) and emitted X-rays (PIXE; particle-induced X-ray emission) were the basic components of the setup. The method is based on measurement of internal blank concentrations, i.e. measurement of the blank concentration outside the aerosol deposit in each sample, and the use of two sizes of the beam in order to improve the MDL of the analysis. Large beam size covering the entire aerosol deposit was used to obtain quantitative analysis with PIXE. Small beam was used to obtain relative elemental concentrations with PESA and PIXE, which were transformed to absolute values by the aid of large-beam analysis. The small-size-beam served two purposes: to make internal blank measurements feasible and to improve the signal ratio of aerosol-deposit to backing. Compared with the traditional way of analysis, using a beam that is larger than the deposit and specially prepared blank samples, the new method reduced the MDL of C, N and O by a factor of 130, 70 and 90, respectively. The new method was applied to aerosol samples collected in the upper troposphere and the lowermost stratosphere from the CARIBIC platform. As far as the authors know, these measurements are the first quantitative determinations of C, N and O in the aerosol of this part of the atmosphere. The results show that these elements together with sulfur are major components of the aerosol.     

基于电力线载波的电表箱安全监控系统硬件设计

提出一种基于电力线载波技术的电表箱安全监控系统的硬件设计方法。介绍电表箱安全监控系统监控前端的硬件结构,给出载波芯片PL2102、单片机AT89C51及其接口电路和载波信号发射与接收电路的设计方法和电路图。