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1.
Using a corrected sum rule and a generalized virial identity, we study the analytical expression for entire modes of the collective elementary excitation spectrum in a trapped Bose–Einstein condensate at any atom number. Explicit analytical formulas for the spectrum are obtained for the harmonic traps with both spherical symmetry and axial symmetry using the gaussian approximation for the N-body ground-state wave function of the condensate. These formulas give the simple dependence of all energy levels on the atom numbers, their interaction strength and trap geometry parameters. 相似文献
2.
中频反应溅射SiO2膜与直流溅射ITO膜的在线联镀 总被引:2,自引:2,他引:0
多数ITO透明导电玻璃生产线在实现SiO2膜与ITO膜在线联镀时,应用SiO2靶射频溅射沉积SiO2膜工艺和ITO靶直流溅射沉积ITO膜工艺,如果SiO2膜应用硅靶反应磁控溅射工艺,存在这种工艺是否可以与ITO靶直流溅射沉积ITO膜工艺在线联用以及如何实现联用的问题。作者对现有的生产线进行了改造设计、加工,做了大量实验、质谱分析和多项测试研究,成功地实现反应溅射SiO2膜与ITO膜在线联镀,做到SiO2镀膜室的工作状态的变化基本上不影响ITO镀膜室的工艺条件。 相似文献
3.
ST Chui 《Canadian Metallurgical Quarterly》1991,43(13):10654-10658
4.
在竹坑水库大坝安全鉴定中,认真分析了该工程存在的主要问题,并针对大坝的结构稳定和渗流稳定作了详细的分析论证. 相似文献
5.
A brown coal, peat and oil shale were subjected to a rapid pyrolysis process and medium-heat-value gases together with tar were collected. The char residue was of high activity and suitable for gasification to create a two-stage gasification system. The coal-tar is used for manufacturing liquid fuels and chemicals. 相似文献
6.
In reverse engineering, geometrical information of a product is obtained directly from a physical shape by a digitizing device. To fabricate the product, manufacturing information (usually tool-path) must be generated from a CAD model. The data digitized must be processed and in most cases, a surface model is constructed from them using some of the surface fitting technologies. However, these technologies are usually complicated and the process for constructing a surface patch from a massive digitizing data is time-consuming. To simplify the process for getting tool-path information, a simple algorithm is proposed in this paper. The algorithm is used to generate a 5-axis machining tool-path. Instead of implementing any complicated surface fitting techniques, a direct method is proposed for constructing three-dimensional (3D) triangular mesh from the digitizing data with the mesh points considered as the tool contact locations. Depending on the locations of the points digitized, a decimation procedure is applied such that some of the digitizing data will be filtered out. Then, the tool axis orientations which must be determined in 5-axis tool-path are calculated and the tool center locations are determined accordingly. A 3D biarc fitting technique is applied for all the tool center locations so that a complete 5-axis tool-path is obtained. 相似文献
7.
NAT穿越是多媒体传输技术中的一个重要研究课题,STUN解决方案能解决部分NAT的穿越问题,但是还有一定的弊端.在STUN技术的基础上,介绍了NAT路由器的识别方法,详细分析并设计一种解决NAT路由器穿越问题的算法.并对处于不同NAT路由器环境下的直接通信给出一种解决方案.既提高了NAT路由器的识别效率,也改善了通信质量. 相似文献
8.
Tungsten wires and porous NiAl prepared through directional solidification and selective dissolution
Zhilong Zhao Jianjun Gao Lufeng Wei Kai Chui 《Materials and Manufacturing Processes》2017,32(16):1817-1822
The combination of directional solidification and selective dissolution was applied to fabricate tungsten (W) wires and porous NiAl matrix. A NiAl–W pseudobinary eutectic alloy with 1.5?at.% tungsten was directionally solidified in a Bridgman-type oven at 1700°C. Results confirmed that the relationships of the growth rate with the interfibrous spacing and diameter of W fibrous phases in the directionally solidified samples are in accordance with the Jackson and Hunt (J?H) model. Afterward, the NiAl matrix was selectively dissolved in an HCl:H2O2 solution to reveal W wires, which present various three-dimensional (3D) morphologies at different growth rates. The W fibrous phases in the NiAl–W alloy samples were then selectively removed with a mixed etchant of ammonium acetate to form a porous NiAl matrix at a constant potential. Dynamic corrosion curves revealed that etching W from the NiAl matrix was inhibited after 2–3?h. The porous structures of NiAl after removing W phases are linked to the 3D morphologies of W fibrous phases embedded in the NiAl matrix. The aspect ratio of W wires and the structures of porous NiAl can be adjusted by selecting the process parameters of this combined technology. 相似文献
9.
构造了一个二元组合型三角插值多项式算子,使该算子对任意的关于变量x、y均以2π为周期的连续函数f(x,y)都能在全平面上一致地逼近,且具有最佳收敛阶。 相似文献
10.
采用溶胶-凝胶法分别在晶态衬底Si/SiO2/Ti/Pt和无定形态衬底Si/SiO2上制备了ZnO压电薄膜.以X射线衍射仪和原子力显微镜研究了薄膜的002择优取向度和表面形貌.结果表明,采用溶胶-凝胶法在Si/SiO2/Ti/Pt和Si/SiO2衬底上都能制备出具有较好择优取向,表面粗糙度低的ZnO薄膜,而且由于Pt和ZnO的晶格失配度较小,在Si/SiO2/Ti/Pt衬底上生长的ZnO薄膜形成002择优取向的退火温度低于在Si/SiO2衬底上生长的薄膜形成002择优取向的退火温度. 相似文献