基于OMAPL138 FPGA构架的PC104主板检测系统

为了对PC104主板进行自动检测,分析了PC104主板工作原理及其总线时序,提出了一种基于ARM FPGA的嵌入式检测系统的设计方案。该方案采用德州仪器(TI)双核架构的高性能芯片OMAPL138中的ARM核来实现检测系统的应用管理,DSP核实现数据的处理,并利用FPGA技术来实时采集PC104总线数据。检测系统在Linux操作系统下,通过人机交互方式实现了PC104主板的各种功能的自动检测。实验结果显示该检测快速可靠,为PC104主板的自动检测提供了一种有效的方法。     

NOVEL TERAHERTZ PHOTOCONDUCTIVE ANTENNAS

The photoconductive (PC) antenna is a key device for the recent terahertz (THz) photonics based on laser-pumped generation and detection of THz radiation. In this paper we report on two new types of PC antennas: the Schottky PC antenna and the multi-contacts PC antenna. The former one is able to detect THz radiation intensity without the time-delay scan and useful for applications where spectroscopic information is not important, such as the THz intensity imaging. The latter one is useful for the polarization sensitive THz spectroscopy, such as the THz ellipsometry. The characteristic features of these new types of PC antennas are studied by using a THz time-domain spectroscopy system.     

Computer software for identification of noise source and automatic noise measurement

A new computational system for the environmental noise measurement and analysis has been developed. The system consists of binaural microphones, a laptop PC, and analysing software. A target noise is recorded automatically depending on the specified background noise level, and the acoustical parameters are calculated simultaneously. These functions allow for precise field measurements. The system is equipped with a template-matching algorithm for the identification of noise source. This function was implemented to avoid the effect of an interrupting sound such as voice and wind blowing during a measurement. Noise analyses in this system are based on the model of human auditory system. In addition to the time-series data of sound level, the important acoustical parameters of noise source are extracted from the running autocorrelation function (ACF) and the inter-aural cross-correlation function (IACF). It has been found that those parameters are strongly related to the auditory primary sensations and spatial sensations. Evaluation of the environmental noise based on these functions is another feature of this system. This paper describes the effectiveness of the ACF and the IACF analysis for analysing acoustical properties of noise and for evaluating the subjective response to noise.     

ESR数据系统的研制

报道了电子自旋磁共振谱仪与IBM PC微型机联用,建立了所需要的硬件系统,包括接口和放大器,研制了分辨率为12位的AD/DA转换器,达到同步采样控制,并实现了X-Y记录仪,示波器,绘图仪与打印机的输出,同时系统软件配有信号采样、信号累加、信号平滑、谱线加减、测量g因子及A值,ESR谱的一、二次积分等一系列数据处理程序,还具有谱线模拟、线形分析等一些应用软件,对于谱的定量和解析极为方便,大大提高了谱仪的功能.     

Spectral data compression using weighted principal component analysis with consideration of human visual system and light sources

This paper proposed two weight functions based on principal component analysis (PCA) to reserve more colorimetric information in spectral data compression process. One weight function consisted of the CIE XYZ color-matching functions representing the characteristic of the human visual system, while another was made up of the CIE XYZ color-matching functions of human visual system and relative spectral power distribution of the CIE standard illuminant D65. The improvement obtained from the proposed two methods were tested to compress and reconstruct the reflectance spectra of 1600 glossy Munsell color chips and 1950 Natural Color System color chips as well as six multispectral images. The performance was evaluated by the mean values of color difference under the CIE 1931 standard colorimetric observer and the CIE standard illuminant D65 and A. The mean values of root mean square errors between the original and reconstructed spectra were also calculated. The experimental results show that the proposed two methods significantly outperform the standard PCA and another two weighted PCA in the aspects of colorimetric reconstruction accuracy with very slight degradation in spectral reconstruction accuracy. In addition, weight functions with the CIE standard illuminant D65 can improve the colorimetric reconstruction accuracy compared to weight functions without the CIE standard illuminant D65.     

QCD Sum Rule Study of π_1S States

We study the states π_1 (1600) and π_1 (2015) in the QCD sum rule.We classify the tetraquark currents of the quantum numbers I~GJ~(PC)=1~-1~(-+),and find that the flavor structure (3 (×) -6)(+) (6(×)3) is preferred when using a diquark-antidiquark construction.By using both the SVZ and finite energy sum rules,we obtain a mass around 1.6 and 2.0 GeV,for the states with the quark contents qqqq and qsqs,respectively.We also study their decay patterns.     

New developments on electrochemical etching processes at the atomic energy organization of Iran

Some highlights of new developments made in our laboratory at the Atomic Energy Organization of Iran on chemical and electrochemical etching (ECE) of polymer track detectors like polycarbonate (PC) are presented. They include introduction of new ECE chamber systems and methods for production of ECE signs and symbols, and a new versatile ECE chamber (VECE) system for multi-purpose, multi-size, and/or multi-shape detector processing; determination of photoneutron doses in and around high-energy X-ray beams of a 20 MV medical accelerator; verification of the Smythe and Mason equations for ECE of tracks in polymers; ECE of alpha and recoil tracks in PC using PMW, PEW and PEMW etchants; introduction of a novel method using ethylene diamine for treatment of PC detectors with its applications, for example in precision removal of surface layers of PC (e.g. bulk removal rates of about 0.04, 0.15, 0.36, 0.66, and 1.33 mm min⁻¹ for 60%, 65%, 70%, 75% and 80% ethylene diamine solution (v/v) in water respectively, with no effects on its transparency), and in significant reduction of background track density of PC detectors, in alpha energy discrimination and alpha spectrometry; and development of an image processing system for track counting and measurements; etc. Some main results are reviewed and discussed.     

Dynamically tunable multifunctional QED platform

Solid-state quantum electrodynamics(QED) not only demonstrates basic principles of quantum physics, but also provides key support to future quantum technologies. However, the non-modifiability of the fabricated solid-state QED systems limits their flexibility and versatility in manipulating light-matter interaction, and severely hinders their practical applications. Here, we put forward an approach of multi-dimensionally manipulating light-matter interaction to realize a dynamically tunable multifunctional QED platform by combining the local light-induced refractive index modulation(LRIM) and strong dispersion characteristic of the photonic crystal(PC) waveguide. We demonstrate three significant functions of the platform as examples:switch control between weak and strong couplings on demand, distant quantum entanglement, and a directional single photon source with high brightness and efficiency. These functions are strongly robust against positioning error of the quantum emitter,and can be facilely realized only by local LRIM on one PC waveguide. Our work paves a new way for the realization of multifunctional quantum devices.     

Stable zirconia-erbium doped multiwavelength fiber laser by precise control of polarization states

A compact zirconium-erbium doped fiber (Zr-EDF) based multiwavelength fiber laser (MWFL) with stable output comb is proposed and demonstrated. The MWFL utilizes a 3 m long Zr-EDF with an erbium concentration of 3000 ppm and pumped by a 1480 nm laser diode (LD) as the active gain medium. A fiber based multimode polarization controller (PC) is used to precisely control the polarization states of the oscillating modes in the MWFL, distributing the total energy of the system among the lasing wavelengths in order to overcome the mode-suppression and mode-competition that arises from homogenous line broadening. The MWFL is capable of generating up to four lasing wavelengths with average peak powers of 0.08 dBm in the extended L-band of 1600 nm. The lasing wavelengths have a 3-dB linewidth of 0.1 and an extinction ratio of 40 dB as well as highly stable, with minimal fluctuations of less than 0.6 dB observed in the peak powers of the lasing wavelengths over a period of 1 h. The proposed system allows for the realization of a compact, cost-effective and stable erbium based MWFL capable of operating at room temperature.     

高温超导热图像信号采集和处理系统

本文介绍一种高温超导热图像信号采集和处理系统，采用在ＰＣ机中插入采集板的硬件结构和Ｃ语言与汇编语言混合编程的软件设计方法，实现了对高温超导热图像信号的采集和图像处理，图像管理，图像显示等多种功能。