Effect of positive ions on the microwave generation in a low-voltage vircator

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.     

The influence of vacuum conditions on the microwave generation in a vircator

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.     

行波热声发动机的多负载声功输出特性

为进一步提高热声发动机的声功输出能力并为驱动多负载做准备,提出了热声发动机声功的多路引出方案。实验中以氮气为工质,工作压力为2．4MPa,在热声发动机环路压比稳定在1．20的情况下,从环路声容和谐振管处同时引出声功,获得了389．95W的最大声功,11．3％的最大声功输出效率以及16．0％的最大声功输出炯效率,这比单独从环路引出的最大声功和效率分别提高了51．4％,24．6％以及19．4％。     

Measurement of the influence of dispersion on white-light interferometry

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.     

Modeling of a vircator with internal TEM feedback

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)     

The effect of quantum dispersion on laboratory feedback optimal control

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.     

The influence of dispersion on journal impact measures

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,...     

The influence of a dispersion of particles on the sintering of metal powders and wires

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.     

Investigation on influence of dimensions of ice containing ozone micro-bubbles on characteristics of ozone concentration

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.     

Surface wave dispersion characteristics of a corrugated strip line

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.     

产品-包装-运载体系统动态特性研究

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.     

Observations on the growth characteristics of the research output of Turkish physicists based on a selective citation analysis

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.     

线性压缩机RC负载全阻抗输出特性研究

建立了线性压缩机的理论分析模型,考虑了间隙损失,并对一系列典型工况进行了分析计算,预测了压缩机的输出特性.用阀门与气库构成RC负载,实验测量了压缩机多种工况下的输出特性,验证了理论预测的准确性.     

Hydrodynamic mechanisms of the influence of injection on the classification characteristics of a hydrocyclone

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.