共查询到20条相似文献,搜索用时 0 毫秒
1.
The effect of vacuum conditions on the characteristics of microwave generation in a nonrelativistic electron beam with a virtual cathode (VC) formed in a retarding field (low-voltage vircator) has been experimentally studied. The ionization of residual gases in the working chamber of a low-voltage vircator leads to displacement of the VC out of the interaction space, which results in breakdown of the microwave generation. The experimental data agree with the results of numerical simulations. 相似文献
2.
V. D. Selemir A. E. Dubinov B. G. Ptitsyn A. A. Evseenko V. A. Letyagin R. K. Nurgaliev V. G. Suvorov A. V. Sudovtsov 《Technical Physics Letters》2001,27(11):967-969
The effect of residual gases on the lifetime of a virtual cathode (VC) was studied. Dependence of the output pulse energy of a high-power vircator on the vacuum conditions was studied. It is demonstrated that a rough vacuum of 5×10?4 Torr achieved with a mechanical pump is sufficient for a vircator operation without significant loss of the output radiation energy. The experimental data agree with a model of the mechanism of VC degradation as a result of the gas ionization. 相似文献
3.
4.
White-light interferometry is a well-established method for measuring the height profiles of samples with rough as well as with smooth surfaces. Because white-light interferometry uses broadband light sources, the problem of dispersion arises. Because the optical paths in the two interferometer arms cannot be balanced for all wavelengths, the white-light correlogram is distorted, which interferes with its evaluation. We investigate the influence of setup parameters on the shape of the correlogram. Calculated values are compared with experimental results. 相似文献
5.
The Karat electromagnetic PIC code is used for computer modeling of a vircator with internal TEM feedback proposed by the
authors. It is shown that the output power can be effectively controlled by varying the feedback length.
Pis’ma Zh. Tekh. Fiz. 25, 89–94 (October 26, 1999) 相似文献
6.
7.
Abstract The effect of quantum dispersion (i.e. a multitude of quantum states corresponding to each value of an observable) on laboratory feedback optimal control is studied. It is shown by numerical and analytical means that including the variance of the observable in the objective functional as well as the presence of modest noise in the controls can steer the system into a low-variance quantum state or, if possible, into an eigenstate of the observable. 相似文献
8.
Scientometrics - A family of measures of a journal’s impact is considered that takes account of the dispersion, as well as the mean, of the number of citations in a journal. These measures,... 相似文献
9.
A dispersion of fine, stable particles is known to inhibit the sintering of metal powders and wires. This can be understood as an effect of the dispersed particles on the efficiency of the sources and sinks between which matter flows during sintering. Well-wetted particles cause the free surface of the metal containing them to become less effective as a source of matter because, as the surface recedes, particles are exposed and a new, high energy interface is created. Particles on grain boundaries, too, make the removal of matter from the boundary more difficult because they pin the boundary dislocations which (at a microscopic level) are the sites from which atoms are detached.The result is that sintering can proceed only if a threshold driving force is exceeded. This threshold depends on the size and volume fraction of particles; its magnitude is different for free surfaces and grain boundaries; and it may change as sintering proceeds. Because of this, some mechanisms of sintering—particularly those leading to desinfication—are inhibited more strongly than others.These ideas are developed quantitatively, and the results presented as sintering maps which show the degree to which each mechanism of sintering is inhibited. The predictions of the model are compared with the results of published experimental observations of inhibited sintering. There is broad agreement, though certain interesting discrepancies remain. 相似文献
10.
Addition of sterilization and deodorization capabilities to ice is effective for a cold storage of food. Therefore, authors clarified the characteristics of ozone micro-bubbles (MBs) concentration fixed in the ice and ozone gas concentration released due to melting. In this paper, ice with different dimensions are prepared by cutting and crushing the formed ice containing ozone MBs, after which influences of dimensions of cut and crushed ice on the above characteristics are examined. Furthermore, using ice slurry is more effective to cool fresh food; therefore, a pseudo ice slurry formed by mixing crushed ice containing MBs with pure water is investigated. Cut ice and original uncut ice mixed with pure water, respectively, are also investigated as a reference. And validities of above ice mixed with pure water, respectively, are shown by measuring ozone concentration in water. Finally, oxidation characteristics due to ozone gas released into fish oil are also clarified. 相似文献
11.
12.
Dispersion characteristics of surface wave in a new corrugated strip line with low attenuation in the range from decimetre
(ultrashort) to centimeter waves (microwaves) have been studied. The slowing and attenuation of the fundamental mode in the
line have been numerically simulated for a broad frequency range using the finite element method. 相似文献
13.
产品-包装-运载体系统动态特性研究 总被引:9,自引:7,他引:2
为缓冲防震系统的设计与评估提供一种新的结构动态分析方法,将复杂耦合结构系统的动态逆子结构分析方法应用于运输包装工程中.从系统分析的角度建立用于确定"产品-包装-运载体"在系统与部件水平的动态特性的实验技术理论.通过对一个集总参数模型实例在系统水平的传递函数的计算,验证了所建立理论的有效性. 相似文献
14.
15.
16.
A comparison has been carried out between the scientific production of Turkish physicists in the periods 1961-1971 and 1994-2000,
by considering articles (written singly or in collaboration with scientists of different nationalities) which have received
at least ten citations. The results show that in 30 years, appreciable increases have occurred in the number of authors making
significant contributions and in the number of papers based on research carried out in Turkey.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
17.
18.
19.
20.
Hydrodynamic mechanisms of the influence of injection on the classification characteristics of a hydrocyclone 总被引:1,自引:0,他引:1
The hydromechanics in a hydrocyclone with an injector is investigated on the basis of the performed experiments and mathematical
modeling. Special emphasis is placed on elucidation of the mechanisms of action of injection on the restructuring of hydrodynamic
fields and finally on the mechanisms of classification of particles in the hydrocyclone. 相似文献