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The phylogenetic position of Dictyostelium inferred from 18S rRNA data contradicts that from protein data. Protein trees always show the close affinity of Dictyostelium with animals, fungi, and plants, whereas in 18S rRNA trees the branching of Dictyostelium is placed at a position before the massive radiation of protist groups including the divergence of the three kingdoms. To settle this controversial issue and to determine the correct position of Dictyostelium, we inferred the phylogenetic relationship among Dictyostelium and the three kingdoms Animalia, Fungi, and Plantae by a maximum-likelihood method using 19 different protein data sets. It was shown at the significance level of 1 SE that the branching of Dictyostelium antedates the divergence of Animalia and Fungi, and Plantae is an outgroup of the Animalia-Fungi-Dictyostelium clade.  相似文献   
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Superconductive coaxial cable has been investigated to survey its feasibility as a communication medium with enormous capacity. The measurements of the frequency and the temperature dependences of the attenuation of coaxial pairs show that dielectric loss is dominant at 4.2 K, but conductor loss increases and gets the attenuation sensitive to temperature as 5 K is exceeded at a few gigahertz. The effect of periodic impedance lrregularities, which is the greatest problem in the transmission characteristics, has been solved by the improvement of the manufacturing process based on spectral analysis of the dimensional variations of the materials, and it is suggested that superconductive coaxial line is applicable to wide-band communication. A thermal insulation pipe for the cable is manufactured and its insulation efficiency is measured. The feasibility of superconductive coaxial cable Will be increased not only by developing the refrigeration system, but also by applying superconductive materials with low surface resistance and critical temperatures higher than lead.  相似文献   
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A fabrication technique of high-purity vertically aligned single-walled carbon nanotubes (VA-SWCNTs) using atmospheric pressure plasma enhanced chemical vapor deposition is presented. Although densely mono-dispersed Fe-Co catalysts of a few nanometers is primarily responsible for VA-SWCNT growth, carbon precipitation was virtually absent in the thermal CVD regime at 700 °C. On the other hand, high-purity VA-SWCNTs without measurable defects were grown at 4 μm min−1 by applying atmospheric pressure radio-frequency discharge (APRFD) which has been previously developed for this purpose. The results proved that cathodic ion sheath adjacent to the substrates, where a large potential drop exists, also plays an essential role for the controlled growth of SWCNTs, while ion damage to the VA-SWCNTs is inherently avoided due to high collision frequency among molecules in atmospheric pressure. Operation regime of APRFD and tentative reaction mechanisms for VA-SWCNT growth are discussed along with optical emission spectroscopy of near substrate region.  相似文献   
5.
钢质屋     
项目使用了3.2mm厚的钢板.采用制造汽车的技术,没有使用任何梁柱。委托人Hirose教授从小就是是铁路模型的爱好者,收集了近千件火车模型。他想居住在一种货运列车的环境中。项目为了满足场地L形的特征.将建筑设计成了货车蜷缩成L形停在一个斜坡上的场景。  相似文献   
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项目坐落在以石墙和石板路闻名的金山城堡脚下。那是一个社区中心,有导游设施和面向当地居民的学习手工和印染的工房。项目中心有6m的高差。考虑到这个特征,设计旨在形成一个松散的连接,将两个设施联系起来,并且与旁边围绕的丰富的自然留有距离。  相似文献   
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This article numerically scrutinizes magnetohydrodynamic flow of a nanofluid due to a nonlinearly curved stretching surface with third order slip flow conditions. The third order slip flow condition has not yet been discussed in fluid dynamics research. The mathematical modeling of the flow problem is given in partial differential equation form. The governing partial differential equations are transformed to high order ordinary differential equations using the similarity transformation and then solved numerically using a boundary value problem solver, bvp4c from Matlab software. The effect of the governing parameters on the flow of the velocity profile, concentration, and heat transfer characteristics are studied. Also graphs of the skin friction coefficient, local Nusselt number, and Sherwood number are drawn and their numerical values are tabulated. The numerical results of the study are compared with previously published articles in the limiting condition. The velocity of the flow field is reduced as the third order slip parameter and the first order slip parameter rises, but the velocity grows as the values of the second order slip flow parameter are elevated. The findings also indicate that the local Nusselt number is depreciated but local Sherwood numbers are elevated when the Soret and Dufour numbers are larger.  相似文献   
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The objective of this study is to show the effect of guide vane geometry on the performance. In order to overcome the disadvantages of vertical axis wind turbine, a straight-bladed vertical axis wind turbine (S-VAWT) with a directed guide vane row has been proposed and tested by the authors. According to previous studies, it was clarified that the performance of the turbine can be improved by means of the directed guide vane row. However, the guide vane geometry of S-VAWT has not been optimized so far. In order to clarify the effect of guide vane geometry, the effects of setting angle and gap between rotor blade and guide vane on power coefficient and starting characteristic were investigated in the experiments. The experimental study of the proposed wind turbine was carried out by a wind tunnel. The wind tunnel with a diameter of 1.8m is open jet type. The wind velocity is 8 m/s in the experiments. The rotor has three straight blades with a profile of NACA0018 and a chord length of 100 mm, a diameter of 0.6 m and a blade height of 0.7 m. The guide vane row consists of 3 arc plates.  相似文献   
10.
The chemical and physical properties of coal are strongly affected by the upgrading process employed. For high-moisture coals, upgrading involves thermal dehydration to improve the calorific value of the coal on mass basis. This study evaluates the feasibility of upgrading a low-rank/grade coal using the oven drying method. The objective of this research work is to study the drying characteristics of low-rank coals and to understand the factors affecting the quality of dried low-rank coals. This article describes laboratory experiments conducted on the characterization of the low-rank coals before and after the drying process. The results on drying kinetics, re-absorption of coal samples, and proximate analysis of coal samples before and after drying are discussed. It was found that the upgrading process produced coal with better heating value and combustion characteristics than those of the raw coal samples.  相似文献   
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