New band system of YbI molecule

Thermal emission spectrum of YbI molecule has been photographed for the first time in the spectral regionλλ 6100–6400 Å using Saha’s high temperature furnace at a reciprocal linear dispersion of 7.3 Å/mm. A total of 52 single-headed and violet degraded bands have been recorded and are classified into a single system. Vibrational analysis has been carried out and it has been suggested that system arises from the ground state with the vibrational constantω″ _e=153.0 cm^?1.     

Optical Recording Performance of Azo Nickel Chelate Thin Film

1IntroduCtionAndyeshavebeenwidelystudiedasmaterialsforreverwhleoPticalstorae,forholographasanexamPle,inwhichisomerizatiOnofazomoeculesekistSbetWeentransandcisform['~'].HOWever,therearetwomainproblemswhichhavelindtedtheirfurtherpracticalaPplications.oneisthatthesbetransformationspeedbetweenisomers,vawingfroInseveralhacrosecondstoseveralseconds,can'tmeetthehighspeeddemandofdatastorage.Theotheristhattheunstablecisstateofazodyesthermallyre-isomerizestothemorestabletransisomerverycommnly.Aithou…     

Effect of the nonlinearity of the CCD in Fourier transform profilometry on spectrum overlapping and measurement accuracy

In Fourier transform profilometry (FTP), we must restrain spectrum overlapping caused by the nonlinearity of the charge coupled device (CCD) and increase the measurement accuracy of the object shape. Firstly, the causes of producing higher-order spectrum components and inducing spectrum overlapping are analysed theoretically, and a simple physical explanation and analytical deduction are given. Secondly, aiming to suppress spectrum overlapping and improve measurement accuracy, the influence of spatial carrier frequency of projection grating on them is analysed. A method of increasing the spatial carrier frequency of projection grating to restrain or reduce the spectrum overlapping significantly is proposed. We then analyze the mechanism of how the spectrum overlapping is reduced. Finally, the simulation results and experimental measurements verify the correction of the proposed theory and method.     

New theoretical analysis ofv 2 0→1Q-bands of ammonia

Summary The analysis ofQ-band infra-red transitionsv ₂0→1 of ammonia has been performed by using existing data and a simple polynomial expansion up to the tenth order ofJ andK. The lines withK=3 require an additionalJ-dependent term because of theK-splitting effect. In this manner, the spectrum has been reproduced within the accuracy of the experimental data. New experimental lines withJ≦20 have been reported or assigned. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

Detection of a directly modulated terahertz light with quantum-well photodetector

We demonstrate a wireless transmission link at 3.9 THz over a distance of 0.5 m by employing a terahertz （Hz） quantum-cascade laser （QCL） and a THz quantum-well photodetector （QWP）. We make direct voltage modulation of the THz QCL and use a spectral-matched THz QWP to detect the modulated THz light from the laser. The small signal model and a direct voltage modulation scheme of the laser are presented. A square wave up to 30 MHz is added to the laser and detected by the THz detector. The bandwidth limit of the wireless link is also discussed.     

Physics possibilities at a linear collider

We review some recent studies about the parameter determination of top quarks,W bosons, Higgs bosons, supersymmetric particles and in the ADD model of extra dimensions at a linear collider.     

New band systems of NiBr molecule in visible region

Thermal emission spectrum of NiBr molecule excited by vacuum graphite tube furnace revealed the existence of ten new band sub-systems in the region λλ 5540-4720 Å which were attributed toA→X,B→X,C→X andD→X transitions. Vibrational analysis was carried out for each of the systems mentioned above.A ² Δ has been suggested as the ground state of NiBr molecule with an electronic interval of about 533 cm^?1. Transitions responsible for NiBr spectrum appear to be of the type²π–²Δ and²Δ–²Δ.     

一种基于CCD的实时测量光栅常数的方法

光栅常数是检验光栅质量的重要参数之一.该文介绍了一种实时检测光栅参数的方法,即利用面阵CCD采集光栅衍射图像信息,通过计算衍射±1级光斑与主极大光斑的能量比得出光栅常数.这种方法具有检测速度快、系统简单、精度高等特点,可用于生产线上光栅的实时检测.     

New band system of MnSe molecule

Thermal emission spectrum of MnSe molecule, excited in high temperature graphite furnace, has been photographed in the spectral region λλ4150–5800 Å at a reciprocal linear dispersion of 7.3 Å/mm. The study reveals the presence of two band systems viz.A–X andB–X in whichB–X is entirely new. While the systemA–X consists of 29 bands, the new systemB–X comprises of 24 single headed and red degraded bands. Vibrational analysis performed suggested that both the systems involve ground state⁶Σ with a vibrational frequencyω″ _e =361.0 cm^?1. Transition responsible for MnSe spectrum appears to be of the type⁶Σ–⁶Σ. An estimation of the ground state vibrational frequency for MnTe molecule gives rise to its value as 280 cm^?1.     

Optimal processing of noisy images in a photodetector with limited dynamic range

A study aimed at optimizing noisy image processing under conditions of strong additive noise has been performed. An algorithm of optimal signal processing was developed and a possibility of improving image quality due to the subtraction of excess additive noise (which limits the photodetector dynamic range) was substantiated. The possibility of technical implementation of noise subtraction due to forced recombination of charge carriers in the photodetector is experimentally confirmed. The proposed approach to design processing systems makes it possible to improve the quality of recorded images under noisy conditions without any changes in the photodetector design.     

New reformulation of the Fourier modal method with spatial adaptive resolution for multilayered metallic strip grating

The parametric formulation of the combined boundary conditions method (CBCM) with spatial adaptive resolution is extended to multilayered structures of strip gratings. Furthermore, it is shown that it is not necessary to solve the eigenvalue problem in all the layers of these structures; leading to drastic reduction of the computational load.     

多通道CCD摄像机的数据采集和图像显示

针对多通道CCD摄像机 ,提出了一种多线程数据实时存储的方法。利用多线程提高硬盘读写速度 ,实现高速、大容量CCD摄像机数据的硬盘实时存储 ,并利用定时中断将多通道信号定时分块存储入硬盘 ,存储的CCD摄像机数据被转换为图像文件加以显示。系统的CCD摄像机通道达到 5个 ,每个通道的数据率达到 10MBit/s。通过实验 ,验证了该方法的正确性和有效性     

Exploitation of inter-track interference in a shingled replay system

The expected increase in areal density in hard drives will require very narrow tracks. Tracks which are of a similar width to the read head and which are not separated by guardbands normally suffer from large inter-track interference (ITI) or crosstalk. Here, we show that it is possible to read from tracks which are not separated by guardbands and that are narrower than the head. In addition to the significant increase in areal density obtainable by reducing the unrecorded area of the disk and narrowing the tracks, such a system would also lead to a decrease in data retrieval times. We have identified across-track magnetization constraints for future coding across three adjacent tracks so that it will be possible to read from tracks which are only 73% as wide as the read head. Reading from tracks not separated by guardbands which have been written under these constraints yields an increase in track density of at least 47% greater than that possible in conventional drives.     

Zero biased Ge-on-Si photodetector with a bandwidth of 4.72~GHz at 1550~nm

High quality Ge was epitaxially grown on Si using ultrahigh vacuum/chemical vapor deposition (UHV/CVD). This paper demonstrates efficient germanium-on-silicon p-i-n photodetectors with 0.8~μm Ge, with responsivities as high as 0.38 and 0.21~A/W at 1.31 and 1.55~μ m, respectively. The dark current density is 0.37~mA/cm² and 29.4~mA/cm² at 0~V and a reverse bias of 0.5~V. The detector with a diameter of 30~μ m, a 3~dB-bandwidth of 4.72~GHz at an incident wavelength of 1550~nm and zero external bias has been measured. At a reverse bias of 3~V, the bandwidth is 6.28~GHz.     

利用线阵CCD测量透明介质折射率

根据光线穿过厚度均匀的透明介质平板时所产生的横向偏移量,提出了一种利用线阵CCD和计算机测量透明介质折射率的新方法．该方法充分利用了线阵CCD分辨率高的特点,并且具有一定的实用价值和应用前景．     

一种简易风洞模拟控制系统设计

介绍了简易风洞模拟系统的设计及制作。本设计以XS128单片机为主控芯片,利用涡轮式轴流风机来为小球的运动提供动能。通过在风洞表面安装的CCD传感器来检测小球位置,而后通过PID算法对轴流风机的抽风量进行进一步调校。从而形成一个完整的闭环控制系统,实现对风动系统的模拟。     

Spatial filtering of temporal noise with the Hadamard transformation applied to a photodetector array

The concept of temporal noise spatial filtering when the image is represented in the Walsh-Hadamard basis and the signal is integrated directly on a photodetector is validated. Results are provided which prove that the rule of ordering the rows and columns of the matrix of the original transformation influences the localization and concentration of noise over the image field.