排序方式: 共有21条查询结果,搜索用时 203 毫秒
1.
R. Schmiele W. Lüthy P. -D. Henchoz H. P. Weber 《Applied physics. B, Lasers and optics》1982,29(3):201-203
We report on the operation of a thallium photodissociation laser with an active medium in the form of a thin layer on a quartz wall. Laser emission has been obtained with layer thicknesses below 100 m. This gas laser seems to be feasible with an active volume as small as 10–1 to 10–2 mm3. 相似文献
2.
A. Henchoz 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1968,19(5):689-702
Summary The direct creation of an electron-positron pair by a high-energy charged particle manifests itself in a certain type of track configuration which is known as a trident. A device for automatic scanning and detection of tridents in nuclear emulsion is described. The device consists of two main parts: a TV camera which analyses the magnified image of the emulsion and a logical detection unit which counts all the observed tracks and also counts the track configurations which may correspond to tridents. The performance of the apparatus is discussed. 相似文献
3.
R. Stierlin R. Bättig P. -D. Henchoz H. P. Weber 《Optical and Quantum Electronics》1986,18(6):445-454
We have investigated balanced heterodyne detection in applications where laser intensity fluctuations are the dominant noise source, as, for example, in laser Doppler velocimetry with a He-Ne laser. The suppression of excess noise in comparison with a single receiver detection system is analysed theoretically. In our heterodyne experiment we have compared two different fibre-optic Mach-Zehnder interferometers, both with single-mode polarization-preserving fibres, one in integrated form using a directional coupler, the other one with a dielectric beam-splitter as the optical mixing element. With the former we have verified the theoretical results; with the latter we have demonstrated that with a good balance the fundamental short noise detection limit can be reached. 相似文献
4.
5.
Comparative study of the alignment method on experimental and simulated chromatographic data
下载免费PDF全文
![点击此处可从《Journal of separation science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
One of the major problems in the signal comparison of chromatographic data is the variability of response caused by instrumental drifts and others instabilities. Measures of quality control and evaluation of conformity are inherently sensitive to shift. It is essential to be able to compare test samples to reference samples in an evolutionary analytical environment by offsetting the inevitable drift. Therefore, prior to any multivariate analysis, the alignment of analytical signals is a compulsory preprocessing step. During recent years, many researchers have taken a greater interest in the study of the alignment. The present paper is an updated review on the alignment algorithms, methods, and improvements used in chromatography. The study is dedicated to one‐dimensional signals. Several of the exposed methods have common theoretical bases and can differ through their optimization methods. The main issue for the operator is to choose the appropriate method according to the type of signals to be processed. 相似文献
6.
Conditions for the operation of a Tl photodissociation laser, in view of power optimization, have been determined. A crucial parameter is found to be quenching of the upper laser level. A value for the quenching cross-section of the 72
S
1/2 Tl state by the TlI molecules of 2×10–14 cm2 has been measured. 相似文献
7.
The hydrochloride of the tetrazolyl bioisostere of the neurotransmitter GABA can be easily prepared by means of three simple steps: a Gabriel-type substitution on 4-bromobutyronitrile with Boc2NH, a tetrazole formation by action of azidotributyltin on the cyano group and a deprotection step using gaseous HCl. 相似文献
8.
Analysis of elastic waves from two-point strain measurement 总被引:1,自引:0,他引:1
Provided that the one-dimensional wave equation applies, strain measurement at two sections of a linearly elastic cylindrical rod makes it possible to determine a number of important quantities at an arbitrary section of the rod; for example, strain, particle velocity and power transmission. The equations needed are derived, and the design of an analogue real-time analyzer is presented. The influence of some principal sources of error is analyzed and it is shown that it should be possible to perform accurate evaluation (errors less than a few percent) during a time interval which is not very long compared to the travelling time for a wave between the two gage positions. Comparisons are made between direct measurement and digital evaluation of strain, and between digital and analogue evaluation of particle velocity and power transmission. The discrepancies are typically less than ten percent during a time interval of 20 travelling times between gages. Although these results do not represent what is achievable, the accuracy is sufficient in several applications and demonstrates the feasibility of the method used. 相似文献
9.
A. Henchoz J. P. Piantino 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1967,18(4):617-618
Sans résuméDéveloppé dans le cadre d'un programme de recherches financé par le Fonds National Suisse de la Recherche Scientifique. 相似文献
10.
Geiser L Henchoz Y Galland A Carrupt PA Veuthey JL 《Journal of separation science》2005,28(17):2374-2380
CZE allows to measure the acidic dissociation constant (pKa) of many drug substances. However, determining the EOF intensity may be time-consuming, especially at a low pH. In order to overcome this drawback, a dynamic coating procedure of the capillary was carried out to increase microEOF, and thus to reduce the analysis time. In addition, this coating procedure enhanced migration time stability. The effective mobilities of 15 compounds were measured at different pH, producing pK'a values dependent on BGE ionic strength. The latter values were corrected with the activity coefficient to obtain a "true" pKa value. The 15 investigated compounds were (i) five acids: namely, salicylic acid, benzoic acid, ketoprofen, phenobarbital, and phenol, (ii) four bases: lidocaine, propafenone, propranolol, and quinine, (iii), five ampholytes: sulfanilamide, sulfabenzamide, sulfadimethoxine, sulfadoxine, and sulfisoxazole, and (iv) one zwitterion: cetirizine. The range of determined pKa values was between 1.2 and 11.2, and close to the pKa values available from the literature. 相似文献