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1.
Yang Ju Yo Hirosawa Masumi Saka Hiroyuki Abé 《International Journal of Infrared and Millimeter Waves》2003,24(3):391-397
We developed a compact equipment working at 94 GHz to replace the commonly used network analyzer for nondestructive testing of materials. The compact equipment was designed to measure the variations in the amplitude and phase of the reflected signal from the material relative to a reference signal. A good accuracy of the amplitude and phase measurement of the equipment was obtained in the confirmative experiments. The distribution of a drop of water in a wood plate is clearly visible in the millimeter wave images obtained by the amplitude and phase measurement. 相似文献
2.
Victor Alexandrov 《Geometriae Dedicata》2004,107(1):169-186
Classical H. Minkowski theorems on existence and uniqueness of convex polyhedra with prescribed directions and areas of faces as well as the well-known generalization of H. Minkowski uniqueness theorem due to A.D. Alexandrov are extended to a class of nonconvex polyhedra which are called polyhedral herissons and may be described as polyhedra with injective spherical image. 相似文献
3.
测量反应体系压力变化的装置已有报道,但本文装置具有操作方便、记数准确等优点。 1 实 验 1.1 实验原理及试剂 详见文献。 1.2 装置及仪器 本文的无汞动力学测量装置用于乙炔氢氯化均相催化反应力学研究,其组装图如图1所示。 相似文献
4.
The linearity of the relationship between σT,t2 and (1 + k)2 is studied with the view of using it for the evaluation of GC equipment. Based on appropriate analytical expressions it is concluded that in general this relationship is not linear and that practical procedures for column evaluation should be developed that take this non-linearity into account. 相似文献
5.
Rupert B. Hurley 《Journal of separation science》1980,3(3):147-148
This paper describes a design for an all-glass GC/MS interface. The design has advantages due to low dead volume, lack of column effluent adsorption and degradation, simple interface production and installation, and ease of column mounting/dismounting. 相似文献
6.
Non-destructive in situ determination of pigments in 15th century wall paintings by Raman microscopy
Raman microscopy has been applied to the study of 15th century wall paintings in a chapel of St. Orso Priory palace (Aosta, Italy) in view of their restoration. The use of a transportable instrument has made it possible to work non-destructively in situ without sampling. The main inorganic pigments used by the unknown artist, namely mercury sulphide, azurite, white lead, red and yellow ochre, carbon black and lead tin yellow type I have been identified, and the presence of organic substances and of some decay products (calcium sulphate and oxalate) has been observed. 相似文献
7.
文章简要介绍了“数字信号处理”与“数字信号处理器(DSP)”的发展历史.在数字信号处理的应用中,实时实现是非常重要的,而DSP在实时处理中,扮演了一个重要的角色.文章中还介绍了DSP在实际应用中的一些关键技术,例如DSP的种类和选型,DSP的开发工具,实时软件的开发过程等.最后,还介绍了一些DSP的应用实例,如语音编码器,视频电话和视频会议系统,用于雷达和声纳的DSP并行处理系统 相似文献
8.
Leonard I. Wassenaar Liang-Feng Han Thomas Schiefer Gustav Kainz Luis Araguas-Araguas Pradeep K. Aggarwal 《Isotopes in environmental and health studies》2018,54(3):274-287
Tritium (3H) is an essential tracer of the Earth's water cycle; yet widespread adoption of tritium in hydrologic studies remains a challenge because of analytical barriers to quantification and detection of 3H by electrolytic pre-concentration. Here, we propose a simple tritium electrolytic enrichment system based on the use of solid polymer electrolyte membranes (PEMs) that can be used to enrich 3H in 250–3000?mL environmental water samples to a 10-mL final volume. The IAEA PEM-3H system reported here can produce high enrichment factors (>70-fold) and, importantly, removes some of the deterrents to conventional 3H enrichments methods, including the use of toxic electrolysis and neutralization chemicals, spike standards, a complex electrolysis apparatus that requires extensive cooling and temperature controls, and improves precision by eliminating the need for tracking recovery gravimetrics. Preliminary results with varying operating conditions show 3H enrichments to 70-fold and higher are feasible, spanning a wide range of tritium activities from 5 to 150 TU with a precision of ~4.5?%. Further work is needed to quantify inter-sample memory and to establish lower 3H detection limits. The IAEA PEM-3H system is open source, with 3-D CAD and design files made freely available for adoption and improvement by others. 相似文献
9.
F. Buzek 《Isotopes in environmental and health studies》2013,49(3):70-72
An equipment for the speed δ18O analysis of water samples is described. It used the equilibrium isotopic exchange reaction between water and CO2 gas. Outgasing of samples through capillary without freezing down the samples, together with shaking during the equilibrium time, reduced considerably time for sample preparation. Apparatus is air termostated with hand valves. Measured δ values are not very sensitive to precision of preparation work and reaction conditions, except of temperature. With good temperature control the standard reproducibility of single measurement is better than 0,1‰ 相似文献
10.
Brynne E. Lazarus Matthew J. Germino Jessica L. Vander Veen 《Isotopes in environmental and health studies》2016,52(3):309-325
Application of stable isotopes of water to studies of plant–soil interactions often requires a substantial preparatory step of extracting water from samples without fractionating isotopes. Online heating is an emerging approach for this need, but is relatively untested and major questions of how to best deliver standards and assess interference by organics have not been evaluated. We examined these issues in our application of measuring woody stem xylem of sagebrush using a Picarro laser spectrometer with online induction heating. We determined (1) effects of cryogenic compared to induction-heating extraction, (2) effects of delivery of standards on filter media compared to on woody stem sections, and (3) spectral interference from organic compounds for these approaches (and developed a technique to do so). Our results suggest that matching sample and standard media improves accuracy, but that isotopic values differ with the extraction method in ways that are not due to spectral interference from organics. 相似文献