多光束激光外差高精度测量玻璃厚度的方法

利用基于激光外差测量技术和激光多普勒技术的非接触式多光束激光外差测量方法,得到了光电探测器输出电流的谐波表达式.讨论了该测量方法用于玻璃厚度超精密测量的可行性及理论依据,并利用Matlab软件对不同情况进行了仿真实验.结果表明：该方法在不同入射角时测量平板玻璃厚度最大的误差为0.3%,明显比其他测量方法精度高. 关键词： 外差探测 多光束激光外差 激光多普勒技术 非接触式测量     

Spectral Characterization of Couplings in a Mixed Optomechanical Model *

Abstract:We study the spectrum of single-photon emission and scattering in a mixed optomechanical model which consists of both linear and quadratic optomechanical interactions. The spectra are calculated based on the exact long-time solutions of the single-photon emission and scattering processes in this system. We find that there exist some phonon sideband peaks in the spectra and there are some sub peaks around the phonon sideband peaks under proper parameter conditions. The correspondence between the spectral features and the optomechanical interactions is confirmed, and the optomechanical coupling strengths can be inferred by analyzing the resonance peaks and dips in the spectra.     

A Novel “Turn On” Glucose-Based Rhodamine B Fluorescent Chemosensor for Mercury Ions Recognition in Aqueous Solution

A novel “turn-on” fluorescent sensor based on glucose and rhodamine B for detection of mercury ions was designed and synthesized. The fluorescent sensor showed an extreme specificity for mercury ions than for other metal ions in aqueous solution. On adding mercury ions to the solution of glucose-based rhodamine B sensor, the absorption and fluorescence signals enhanced remarkably at 567 and 587 nm, respectively. Titration of sensor with mercury ions showed 1:1 stoichiometric reaction. The cyclic voltammetric measurement of an increasing amount of mercury ions in the solution of glucose-based rhodamine B sensor commendably showed the change in the fluorescence characteristics. Furthermore, the successful detection of trace amount of mercury ions in water indicated that glucose-based rhodamine B sensor can be used for the detection of the limited mercury ions in drinking water.     

Design of Hamming Code Checker Using Titanium-Diffused Lithium Niobate-Based Waveguide

ABSTRACT

This work presents an electro-optic effect-based design for the widely used Hamming code for checking single bit errors in the received data. The structure is based on Mach-Zehnder Interferometer, designed using Titanium-diffused Lithium Niobate-based waveguides. The proposed device has been successfully tested using the beam propagation method. For a received 7-bit code, the three simultaneously generated check bits are combined to check the error position. Critical performance parameters like extinction ratio (24.39dB), contrast ratio (25.711dB), insertion loss (0.041dB), and amplitude modulation (0.079dB) calculated for the overall device are within acceptable limits for the feasibility of the device.     

Einige Aspekte der Entwicklung radiometrischer Analysen- und Detektionsverfahren

Die Ausnutzung von Quanten- und Teilchenstrahlung zur Analyse von Stoiffverteilungen und Stoffzusammensetzungen hat im vergangenen Jahrzehnt einen beträctlichen und fast unübersehbaren Umfang angenommen.

Es werden mögliche Schicerpunkie der zukünftigen Anforderungen an solche Analysenverfahren — die sich aus der modernen Forschung und Entvicklung ergeben — aufgezeichnet und die Anwendungsmöglichkeiten und der Entwicklungsstand spezieller Verfahren besprochen. Insbesondere werden Mönlichkeiten der Gesamtbilddurstellung, der Scanning-Verfahren und der Oberflächenuntersuchungen dünnster Schichten und Fragen der Strukluraufklärung, der chemischen Bindungen bzw. Bindungskonfigurationen diskutiert.     

Radiophotolumenescence of Irradiated Polymethylmethacrylate Doped with Some Charge Transfer Complexes

Radiophotolumenescence (RPL) of irradiated and non irradiated thin films of polymethylmethacrylate (PMMA) doped with anthracene (Anth) as a donor, and tetracyanoquinodimethane (TCNQ) as an acceptor, has been investigated. The RPL – glow spectrum was recorded to study the characterizing emission bands from the point of view of glow peak position and intensity and hence the prospective relative sensitivities. RFL – signal fading after one month storage in dark at room temperature post gamma irradiation was also studied. PMMA doped with 6:4 donor to acceptor ratio has been proved to be the most sensitive one with less fading regarding gamma detection. On the other hand 2 Anth: 8 TCNQ was found to be the proper dopant concentration ratio for thermal neutron detection.     

The Determination of 222Rn in Drilling Fluids of the KTB Pilot Borehole Using SSNTD Techniques

²²²Rn dissolved in drilling fluids of the KTB (Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschland) pilot hole has been determined using solid state nuclear track detector (SSNTD) technique:The α-sensitive SSNTD CR-39 was used to measure the a-activity of ²²²Rn. Well-defined conditions for Rn-measurements could be established by employing a mica nuclear track microfilter to separate the detector containing air volume from the volume containing the water. This technique has been applied to determine quantitatively the ²²² Rn-concentration as a function of depth of the borehole down to 4000 m.     

Fast Neutron Sensitivity of TL Detectors using Proton Radiator Techniques

TL materials have a small intrinsic sensitivity for fast neutrons. In order to increase this sensitivity one uses hydrogen containing radiators giving recoil protons as a result of the neutron interaction. By combining the proton radiator technique with the use of TL detectors having various glow peaks with a different response to recoil protons an additional sensitivity yield can be reached. The paper deals with the calculation procedure for the (radiator) sensitivity component. For the LiF phosphors TLD-600 and TLD-700 calculated and experimentally determined fast neutron sensitivities are presented for the glow peaks V and VII. The results show that for accident dosimetry a sufficient agreement of the dedector response with the dose-to-fluence conversion factors is obtained.     

An efficient statistics-based method for the automated detection of sperm whale clicks

In this paper, we present a new method for the automated detection of sperm whale regular clicks and creaks based on statistical computations. In the first stage, a spectrogram is computed from the input waveform, followed by a noise normalisation process. A frequency domain filter is then applied, and the energy accumulated in each time frame is calculated. Two-second time-windows are then classified as containing either regular clicks, creaks, or noise based on statistical parameters using a neural network classifier. Finally, previously obtained statistical parameters are used to implement an energy-based detection criterion for the classified time-windows. Individual regular clicks and creaks are isolated by linking contiguous detected time frames. The proposed method was tested on five recordings of sperm whale sounds. Comparison of the detection performances to hand-labelled regular clicks and creaks revealed that this method outperforms two recently reported waveform-based methods when working with the same recordings files. An average percentage of detection of 86.97% was attained for the set of files. This method consumes also little computation time.