ID 原文 译文
21445 发射端信息比特分割为伪随机(Pseudo Noise, PN)码映射块和调制信息块，并分别映射为PN码的索引和调制符号，调制符号的实部与虚部再选择相同的激活的PN码进行扩频。 The bit stream of the transmitter is divided into mapping block of Pseudo Noise (PN) code and informational block of modulation, which are mapped into the index of the PN code and modulation symbol respectively.
21446 仿真与分析结果表明，在相同频谱效率时，N-CIM的误比特率性能比CIM在加性高斯白噪声信道中当误比特率为10–5时具备约2～3 dB的优势，在瑞利衰落信道中当误比特率为10–2时具备约2 dB的优势。 The real part and imaginary part of the modulation symbol are spread by selecting the identical activate PN code. Simulation and analysis results show that N-CIM outperforms CIM by about 2~3 dB inadditive white Gaussian noise channel when the bit error rate is 10–5, and N-CIM outperforms CIM by about 2dB in Rayleigh fading channel when the bit error rate is 10–2 at the same spectral efficiency.
21447 覆膜对浸渍扩散热阴极表面电子发射的影响一直是热阴极研究领域的重点课题。 The impact on impregnated cathode electronic emission, when it is coated by films, is an important studied content in the field of thermionic cathode.
21448 该文采用最新研制的深紫外激光光发射电子显微镜/热发射电子显微镜(DUV-PEEM/TEEM)，对一半覆膜、另一半未覆膜的浸渍扩散阴极试样作了1150 ℃×2 h激活，并对其表面微区的热电子发射像及其随温度的变化作了比较。 A cathode sample is evenly split by impregnated dispenser cathode and coated impregnated dispenser cathode. The sample is activated at 1150 ℃ in the Deep UltraVioletlaser Photo- and Thermal- Emission Electron Microscope system (DUV-PEEM/TEEM) for 2 hours. In this system, the micro- electron emission phenomenon of two cathode and its changes with temperature are compared and studied directly.
21449 结果发现，两种阴极的热电子发射均主要位于孔隙及其邻近颗粒边缘； The results show that the electronic emission of both impregnated cathode and coated impregnated cathode are mainly located at the pores and the edge of the adjacent particles;
21450 随温度升高，未覆膜阴极发射主要集中于孔隙内及周边有限区域内，发射面积增量较小，覆膜则使阴极有效发射区域得以由孔隙及其边缘向距孔隙更远的区域延伸，发射面积大幅增加。 Along with the rise of cathode's temperature, the cathode emission without coating anything is still mainly focused on the pores and nearby narrow regions on cathode surface, that the emission area changed a little. However, for the coated impregnated dispenser cathode, the effective emission area is extended from the pores and its edge to the area far away from the pores.
21451 上述结果首次给出了覆膜浸渍扩散阴极微区的电子发射特征，对于理解该类型阴极发射机理有一定参考价值。 These results for the first time give the electron emission characteristics for impregnated cathode coated with film, which have certain reference value to understand the emission mechanism of this cathode.
21452 平滑l0范数(SL0)算法是一种基于近似l0范数的压缩感知信号重构算法，采用最速下降法和梯度投影原理，通过选择一个递减序列来逐步逼近最优解，具有匹配度高、计算量低、不需要已知信号稀疏度等优点。 Smoothed l0 norm (SL0) algorithm is a compressive sensing reconstruction algorithm based on approximate l0 norm, which uses the steepest descent method and gradient projection principle, by selecting a decreasing sequence to get the optimal solution. It has the advantages of high matching degree, low computational complexity and without knowing the signal sparsity.
21453 但是，其迭代方向为负梯度方向，使得在迭代过程中产生“锯齿现象”，导致在最优解附近收敛速度较慢。 However, the iterative direction of steepest descent method is negative gradient direction, which leads to the "sawtooth phenomenon" and the slower convergence speed in the vicinity of the optimal solution.
21454 牛顿法具有较快的收敛速度，但是对初值的要求较高，并且需要计算Hesse矩阵。 The Newton method has a good convergence speed but has higher requirement of the initial value and needs to calculate the Hessian matrix.