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131.
F. M. Karawajew A. F. Dričko H. Greupner K.-H. Sucker 《Isotopes in environmental and health studies》2013,49(11):396-399
In der Arbeit wird über eine Empfehlung zur Methodik der Weitergabe der Aktivitätseinheit für umschlossene γ-Strahlungsquellen von den Normalen der metrologischen Slaatsämter der UdSSR (WNIIM) und der DDR (ASMW) an Normale niederer Ordnung berichtet. Die Weitergabe der Aktivitätseinheit geschieht durch Vergleich mittels Ionisationskammern. Die Empfehlung bezieht sich auch auf solche Fälle, in denen neben dem Hauptnuklid ein Verunreinigungsnuklid in der Quelle enthalten ist, sowie auf solche, bei denen unterschiedlicher Aufbau der zu vergleichenden Quellen vorliegt. Auβerdem umfaβt die Empfehlung die Methode der Fehlerrechnung. 相似文献
132.
Haishun Liu Chaochao DunLinming Dou Weiming Yang 《Journal of magnetism and magnetic materials》2011,323(12):1667-1670
The output voltage is an important parameter to determine the stress state in magnetic stress measurement, the relationship between the output voltage and the difference in the principal stresses was investigated by a comprehensive application of magnetic circuit theory, magnetization theory, stress analysis as well as the law of electromagnetic induction, and a corresponding quantitative equation was derived. It is drawn that the output voltage is proportional to the difference in the principal stresses, and related to the angle between the principal stress and the direction of the sensor. This investigation provides a theoretical basis for the principle stresses measurement by output voltage. 相似文献
133.
134.
The relationships between the morphological characteristics and the vulnerability of atherosclerotic plaque were analyzed
theoretically and several suggestions were proposed to evaluate the plaque vulnerability. Validated by animal experiments
and clinical studies, the theoretical results were confirmed.
Supported by the National Natural Science Foundation of China (Grant Nos. 10302016 and 60402023), the National Basic Research
Program of China (973 Program)(Grant No. 2006CB503803), and the National Hi-Tech Research and Development Program of China
(863 Program) (Grant No. 2007AA02Z448) 相似文献
135.
The use of non-contact laser techniques for the generation of ultrasound has extended the limits of the application of traditional ultrasonic techniques. This paper focusses on the use of one such non-contact laser technique, known as ‘optical fibre array’, to generate shear and surface waves. The shear wave experimental directivity pattern results are presented and compared with the theoretical results of a single source and an array source. The experimental directivity results for the surface wave are also presented, and compared with the theoretical results. The data show that the array enhances signal generation in the forward direction for both shear and surface waves. The array gain is also discussed. The receiver for the directivity measurements was a contact piezoelectric transducer. 相似文献
136.
XU Yong WANG Binglin 《声学学报:英文版》1993,(3)
The author has made tests for an artificial head transfer system whichis modelled on a Chinese male on its main physical behaviour such as frequencyresponses,frequency response differences between the front and the rear inci-dences,as will as on its important hearing behaviour such as localization,theperception of distance and room dimensions.The results verify that this kind ofartificial head transfer system can be used as one of effective tools of acousticevaluation researches for halls. 相似文献
137.
本文叙述了新铸铝光谱标样的制备过程,制备出的标样具有工艺先进,化学成分均匀,定值准确及校准曲线啮合系数高等特点。通过试用分析,结果与化学仲裁分析结果相符,很好地满足了光谱分析铸造铝合金化学成分对标样的需求。 相似文献
138.
The scattering behavior of P-waves in piezoelectric composites with 1–3 connectivity is studied. The method of wave function expansion is adopted for the theoretical derivations. Analytical expressions are obtained for the distributions of mechanical displacement in z-direction along the circumferences of piezoelectric cylinders. These solutions are used to study the influence of each element of the stiffness matrix and the piezoelectric matrix on the various resonant modes of vibration. Numerical results obtained indicate that perturbations of the elements c44 and e15 significantly affect resonant frequencies and amplitudes, perturbations of c11 and c12 have pronounced effects on resonant modes of high frequencies also. However, the resonant modes are not so sensitive to the perturbations of c13, e31 and e33. The dynamic characteristics of 1–3 connectivity piezoelectric composites exposed here are meaningful for the design and manufacture of sensor/actuator elements by this kind of composites as well as the on-line health monitoring of the mechanical properties variations of the composites itself. 相似文献
139.
Cho G Segal E Ackerman JL 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2004,169(2):328-334
A high temperature magnetic resonance compatible furnace for real time in situ monitoring of materials, processes, and chemical reactions with magnetic resonance imaging and spectroscopy is described. Design issues are analyzed. Example applications are demonstrated with a time sequence of proton images of the binder burnout in a porous green ceramic cylinder containing polyethylene glycol binder at 200 degrees C, and 7Li images of the molten salt LiCl at 700 degrees C. 相似文献
140.
The objective of this paper is to develop a nondestructive method for estimating the fracture toughness (K(IC)) of CrMoV steels used as the rotor material of steam turbines in power plants. To achieve this objective, a number of CrMoV steel samples were heat-treated, and the fracture appearance transition temperature (FATT) was determined as a function of aging time. Nonlinear ultrasonics was employed as the theoretical basis to explain the harmonic generation in a damaged material, and the nonlinearity parameter of the second harmonic wave was the experimental measure used to be correlated to the fracture toughness of the rotor steel. The nondestructive procedure for estimating the K(IC) consists of two steps. First, the correlations between the nonlinearity parameter and the FATT are sought. The FATT values are then used to estimate K(IC) using the K(IC) versus excess temperature (i.e., T-FATT) correlation that is available in the literature for CrMoV rotor steel. 相似文献