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771.
The dependence of the wave resistance coefficients for planar periodic reliefs on the similarity parameters is investigated. It is proved that the wave resistance coefficients of the infinite reliefs and their finite analogs in the case of the whole wave numbers coincide, whereas in the case of the fractional wave numbers they differ.  相似文献   
772.
A problem on low vibrations of a thin spherical shell is considered. A solid of finite dimensions is discretely attached to the shell by means of an elastic rod system. The calculation examples are presented.  相似文献   
773.
The derivation of parametric equations for a limiting surface in the space of internal forces and moments that act in the rod cross-sections, using the basic concepts of plasticity theory and conventional hypotheses of the rod theory, is presented. The plastic properties of rod material are described by the Mises criterion. A case of small displacements and strains under static simple loading is considered. The results of solving a number of problems of constructing limiting curves in the planes of internal forces and moments are given.  相似文献   
774.
Magnetic effects are ubiquitous and known to be crucial in space physics and astrophysical media. We have now the opportunity to probe these effects in the outer heliosphere with the two spacecraft Voyager 1 and 2. Voyager 1 crossed, in December 2004, the termination shock and is now in the heliosheath. On August 30, 2007 Voyager 2 crossed the termination shock, providing us for the first time in-situ measurements of the subsonic solar wind in the heliosheath. With the recent in-situ data from Voyager 1 and 2 the numerical models are forced to confront their models with observational data. Our recent results indicate that magnetic effects, in particular the interstellar magnetic field, are very important in the interaction between the solar system and the interstellar medium. We summarize here our recent work that shows that the interstellar magnetic field affects the symmetry of the heliosphere that can be detected by different measurements. We combined radio emission and energetic particle streaming measurements from Voyager 1 and 2 with extensive state-of-the art 3D MHD modeling, to constrain the direction of the local interstellar magnetic field. The orientation derived is a plane ~60°–90° from the galactic plane. This indicates that the field orientation differs from that of a larger scale interstellar magnetic field, thought to parallel the galactic plane. Although it may take 7–12 years for Voyager 2 to leave the heliosheath and enter the pristine interstellar medium, the subsonic flows are immediately sensitive to the shape of the heliopause. The flows measured by Voyager 2 in the heliosheath indicate that the heliopause is being distorted by local interstellar magnetic field with the same orientation as derived previously. As a result of the interstellar magnetic field the solar system is asymmetric being pushed in the southern direction. The presence of hydrogen atoms tend to symmetrize the solutions. We show that with a strong interstellar magnetic field with our most current model that includes hydrogen atoms, the asymmetries are recovered. It remains a challenge for future works with a more complete model, to explain all the observed asymmetries by V1 and V2. We comment on these results and implications of other factors not included in our present model.  相似文献   
775.
香港工商企业的质量管理大部分都采用西方的质量管理概念。每当范畴扩展到建立人的优质思想和意识时,便遇到不少困难,基于上述问题,作者进行了一系列的研究,希望了解‘文化’与‘优质管理’之间的关系,并将中国的优良文化传统应用于现代质量管理之中。研究结果显示,‘管理哲学’是重要的一环,而我国的哲学极为丰富,作者借此文章,希望引起更多中国人在这方面的兴趣,从而进行更深入地研究和推广。  相似文献   
776.
We report measurements of chromosomal aberrations in peripheral blood lymphocytes from cancer patients undergoingradiotherapy treatment. Patients with cervix or esophageal cancer were treated with 10 MV X-rays produced at a LINAC accelerator, or high-energy carbon ions produced at the HIMAC accelerator at the National Institute for Radiological Sciences (NIRS) in Chiba. Blood samples were obtained before, during, and after the radiation treatment. Chromosomes were prematurely condensed by incubation in calyculin A. Aberrations in chromosomes 2 and 4 were scored after fluorescence in situ hybridization with whole-chromosome probes. Pre-treatment samples were exposed in vitro to X-rays, individual dose-response curves for the induction of chromosomal aberrations were determined, and used as calibration curves to calculate the effective whole-body dose absorbed during the treatment. This calculated dose, based on the calibration curve relative to the induction of reciprocal exchanges, has a sharp increase after the first few fractions of the treatment, then saturates at high doses. Although carbon ions are 2–3 times more effective than X-rays in tumor sterilization, the effective dose was similar to that of X-ray treatment. However, the frequency of complex-type chromosomal exchanges was much higher for patients treated with carbon ions than X-ray.  相似文献   
777.
778.
Nowadays operational models for solar activity forecasting are still based on the statistical relationship between solar activity and solar magnetic field evolution. In order to set up this relationship, many parameters have been proposed to be the measures. Conventional measures are based on the sunspot group classification which provides limited information from sunspots. For this reason, new measures based on solar magnetic field observations are proposed and a solar flare forecasting model supported with an artificial neural network is introduced. This model is equivalent to a person with a long period of solar flare forecasting experience.  相似文献   
779.
The original basis for the Lorentz transformations, and thus special relativity, was the assumption that the observed velocity of interaction of light with matter represents a unique velocity of the electromagnetic wave. This arbitrary decision is not borne out by Maxwell's theories or by any test that might prove that EM energy actually travels in a continuum of velocities. The second postulate as stated by Einstein does not deserve the status of a postulate, as it is at once overly restrictive and ultimately phenomenological-the nature of c is based on experimental measurement rather than on analysis of first principles. The radiation continuum model's (RCM) modified second postulate, however, says nothing about the actual propagation of EM energy, but only of the relative speed with which it must interact with matter to be detected. Utilizing this modified light principle we obtain an intuitive Galilean form invariance for Maxwell's equations. RCM places no upper limit on attainable velocities, and allows for the possibility of communications between humans or particles at speeds far in excess of c. This precludes many of the compatibility problems between the highly successful quantum mechanics and relativity theory  相似文献   
780.
The region of South Atlantic Geomagnetic Anomaly (SAGA) was investigated by the Intercosmos-Bulgaria-1300 satellite, launched on August 7, 1981. On the basis of data obtained from 15 orbits during increased geomagnetic activity in August 1981, a map of the Anomaly was elaborated. Two centres of activity were identified. By means of the EMO-5 electrophotometer on board the Intercosmos-Bulgaria-1300 satellite, the atmosphere glow in lines λ 5577 Å, λ 6300 Å and λ 4278 Å was studied.  相似文献   
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