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121.
目前,我国的信息产业也在不断的飞速发展,而信息化发展的进程中,计算机硬件学科也加入了其发展的行列,并长期以来一直坚持着可持续发展的自主创新理念。本文首先介绍了信息化的发展进程,接着分析了计算机硬件学科的建设的自主创新的坚持的主要原则,最后明确的阐述了计算机硬件学科,在建设的持续自主创新中采取的有利措施。  相似文献   
122.
弓奇 《表面技术》1992,21(5):216-218
介绍铝及铝合金阳极氧化膜颜色的概念和描写,对颜色的儿种测量方法进行了比较,重点分析观察法及其在各国标准中的异同。在此基础上,提出了GB8013中的对颜色进行观察的条件和理论根据。  相似文献   
123.
Two generations of novel linear-dendritic carboxylate surfactants C18-G1-(COONa)2 and C18-G2-(COONa)4 have been synthesized by the divergent method and their structures are characterized by 1H Nuclear Magnetic Resonance and Infrared analysis. The electrical conductivity measurement is used to measure the Krafft temperatures of C18-G1-(COONa)2 and C18-G2-(COONa)4, which are much smaller than those of the corresponding conventional surfactant sodium stearate. The markedly enhanced solubility of two linear-dendritic surfactants is ascribed to the high hydrophilicity of surfactant headgroups induced by the carboxylate and ester groups. The critical micelle concentration (CMC) values obtained from both the electrical conductivity and surface tension measurements indicate that the micellizations of linear-dendritic surfactants become favorable with the increase in the number of the surfactant headgroup. However, the surface activity parameters including the surface tension at the CMC, maximum surface excess, and minimum surface area reveal that C18-G1-(COONa)2 exhibits greater efficiency in absorbing at the air/water interface compared to C18-G2-(COONa)4, owing to their different steric repulsions of the surfactant headgroups. In addition, C18-G1-(COONa)2 and C18-G2-(COONa)4 have higher emulsifying ability than the conventional surfactants sodium stearate and sodium octadecyl sulfate.  相似文献   
124.
含硼金刚石的金属包膜成分及其物相的研究   总被引:1,自引:0,他引:1  
本文采用铁基触媒加入硼铁的方法,在高温高压条件下合成了含硼金刚石,利用电子探针(EPMA),透射电子显微镜(TEM)两种检测手段,分析了含硼金刚石金属包膜的微观组织结构,化学组成成分,各组成成分的物相及其可能形成的原因。研究结果表明:金属包膜的成分及其物相由正交立方结构的(Fe,Ni)3C,面心立方的γ-(Fe,Ni),面心立方的Fe23(C,B)。及少量的FeB,Ni3B组成,这些成份主要来源于原材料,其含量在高温压过程中是瞬间变化的。  相似文献   
125.
采用在铸型中放置石墨片,然后浇注低碳合金钢的方法,制造表面耐磨材料。分析了铸造过程中渗碳的效果及机理,讨论了影响组织和渗层深度的因素。  相似文献   
126.
针对卫星网络高误码率、长延时等特点,提出了一种适合卫星可靠组播的差错恢复方案。该方案采用异或(XOR)编译码的方法,可以一次重传恢复多个丢失的数据包;在此基础上,设计了一种基于重传矩阵预处理的最优重传策略来实现重传数量最小化。仿真结果证明了该可靠组播差错恢复方案在卫星环境中的有效性。  相似文献   
127.
Radiative cooling can achieve cooling effect without consuming any energy by delivering energy into outer space(3K) through"atmospheric window"(8–13 μm). Conventional radiative cooling coating with multi-layer structure was severely restricted during application due to its complex preparation process and high cost. In this study, a single-layer radiative cooling coating with mixture of TiO_2 particles and SiO_2 particles was proposed. The algorithm for calculating the radiative properties of the multi-particle system was developed. Monte Carlo ray-tracing method combined with that algorithm was used to solve the radiative transfer equation(RTE) of the single-layer radiative cooling coating with mixture of TiO_2 particles and SiO_2 particles.The effects of particle diameter, volume fraction and coating thickness on radiative cooling performance were analyzed to obtain the best radiative cooling performance. The numerical results indicated that the average reflectivity of the single-layer radiative cooling coating with mixture of TiO_2 particles and SiO_2 particles in the solar spectrum can reach 95.6%, while and the average emissivity in the "atmospheric window" spectrum can reach 94.9% without additional silver-reflectance layer. The average reflectivity in the solar spectrum and average emissivity in the "atmospheric window" spectrum of the single-layer radiative cooling coating with mixture of TiO_2 particles and SiO_2 particles can increase 4.6% and 4.8% compared to the double-layer radiative cooling coating. This numerical research results can provide a theoretical guidance for design and optimization of single-layer radiative cooling coatings containing mixed nanoparticles.  相似文献   
128.
Gong  ZeYu  Yu  SuPu  Tao  Bo  Gu  ZhenFeng  Wang  JinShan  Ding  Han 《中国科学:技术科学(英文版)》2021,64(10):2186-2199

The accurate estimation of the end-effector’s pose in large operating spaces is the key for the mobile manipulator to realize efficient manufacturing of large and complex components. We propose a novel pose tracking method in large-range using visual fiducial markers, and further propose the layout optimization method for the encoded fiducial markers. A metric named orientational dilution of precision (ODOP) is proposed to evaluate the magnification of the pose estimation error compared with the measurement error of the coded fiducial markers. The distribution pattern of the coded markers is analyzed based on ODOP, and the square-shaped layout is determined to be a satisfactory distribution pattern for the minimum positioning unit of markers, and the side length of the square-shaped layout is further selected. The simulations and experiments prove the effectiveness of the ODOP index. Finally, the square-shaped layout and the designed distribution density for positioning coded markers are adopted to realize the high-precision measurement of large components by the mobile manipulator.

  相似文献   
129.
为了降低玻璃纤维生产成本,提升分束纱产品质量,增加市场竞争优势,根据分束纱生产工艺线特点,从分束器设计开发及工艺技术调整应用方面进行攻关,研制开发出了特殊的拉丝分束装置,解决了拉丝过程中玻璃纤维在分束器处飞丝和浸润剂浪费的问题.  相似文献   
130.
In order to meet the requirements of polymer dielectric materials for high thermal stability and excellent dielectric properties in the application of high-temperature film capacitors, a series of polyimide (PI) films are fabricated by introducing a self-synthesized aniline trimer (ACAT) with a conjugated structure in this work. Since the conjugated ACAT in the main chains of PI improves the electron polarization and carrier mobility of the PI molecular chains, the dielectric constant of the ACAT-PI films is greatly enhanced (4.4–7.4). Meanwhile, the dissipation factor does not increase apparently (0.002–0.013). The dielectric properties are stable even when the temperature is up to 200 °C, the thermal degradation temperature is as high as 450 °C, and the mechanical properties are also excellent (70–105 MPa). Among all the films, the PI film with 5 mol% ACAT exhibits the maximal energy density of 3.6 J cm−3 under the field of 426 kV mm−1, the high tensile strength (90 MPa) and the excellent thermal stability (Td5 = 515 °C). The work paves the way to prepare high-temperature polymer dielectric film materials with high energy storage density.  相似文献   
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