A 24-GHz Patch Array with a Power Amplifier/Low-Noise Amplifier MMIC

This paper presents an active patch array designed at 24 GHz. It can be used as a front-end component for a phased array. A series resonant array structure is chosen which is compact and easy excite. With 5 elements, the array proved a 12-dB antenna gain. A power amplifier and a low noise amplifier are designed on a single GaAs chip (PALNA). Bias switch is used in the PALNA, which greatly reduces the switch loss in a transceiver and increases the efficiency. 20-dB small signal gain is achieved in both power amplifier and low noise amplifier. The active patch array is built by the combination of the patch array and PALNA. The measured active gain of this antenna is 35-dB for the PA mode and 31-dB for the LNA mode. This active patch array can obtain an EIRP of 34 dBm with a total radiated power of 22dBm and a maximum PAE of 32%. To check the noise performance, we applied sources at both normal temperature and 77K (liquid nitrogen) and extracted the noise figure (3.5 dB) of the active antenna by the Y factor method. The results proved that the active antenna is working efficiently as both a transmitting and receiving antenna.     

Sums of Two Exact Powers

An asymptotic formula is obtained for the number of representations of an element of a finite field as a weighted sum of two prescribed powers of primitive elements. This generalises previous work on sums of primitive elements, including that relating to some conjectures of Golomb.     

溅射功率对多层膜质量的影响

用磁控溅射技术制备薄膜，用X射线衍射研究在基片和靶间距离固定的情况下不同的溅射功率对薄膜结构的影响。结果表明：过低的溅射功率下淀积的薄膜有畸变的X射线衍射特征峰，特征峰强度小，半峰全宽大。而比较高溅射功率得到的薄膜有比较尖锐的X射线衍射特征峰，强度高和半峰全宽非常窄。研究表明，X射线衍射特征峰强度小和半峰全宽大的薄膜结构疏松，而强度高和半峰全宽非常窄的薄膜结构致密。     

统计等效多项式非线性系统识别

在平稳激振下的一个非线振动系统，若其响应也是平衡随机过程，该系统可统计等效为一多项多非线性系统，本文介绍统计等效三次多项式的参数估计，系统的多维频率响应应函数以及多项式非线性系统响应的谱分析及谱分析。     

水电工程规划设计方案的自动生成及评价

本文介绍了在水电工程规划设计时，如何利用三次自然样条插值函数在有限个方案的基础上自动生成无限多个方案，然后采用多目标综合决策模型在其中选择最优方案的一种方法．文中还给出了程序流程，并以某水电站正常蓄水位选择作为实例，对方法进行了验证，结果与专家决策完全吻合．     

特定最大功率传输问题探讨

本文通过理论计算给出几种特定情况下的功率传输问题。     

受激喇曼散射在掺铒光纤放大器中的影响

本文在分析了均匀掺杂分布式光纤放大器（d－EDFA）的基础上，提出了沿传输方向掺杂浓度单调下降（单变），和降升结合（两变）的两种渐变型分布式光纤放大器，并用传输方程研究了透明传输和最佳掺杂浓度下，受激喇曼散射对均匀、单变和两变型三种d－EDFA的各种特性的影响．     

Aliasing Effects and Sampling Theorems of Spherical Random Fields when Sampled on a Finite Grid

Aliasing effects are investigated for spherical random fields sampled on a finite grid. Using the spherical harmonics expansion, it is shown that for a band-limited spherical random field its trend and spectrum can be uniquely reconstructed from the sampled field if the sampling points are judiciously designed. Analytical expressions are also obtained for aliasing errors in the trend and the spectrum when the field is not band-limited.     

女性命运的不同阐释--比较《玉米》和《麦穗》

毕飞宇的《玉米》和迟子建的《麦穗》都以书写女性人生为主要内容,但由于作家自身经历、人生观念的差异,两篇题材相似的作品对女性命运的阐释有很大不同,前者描述的是一个权欲的悲剧,后者则用美好的人性温暖了女主角原本走向黯淡的人生。     

文化生产场域中符号权力的形成--以文学艺术场域的分析为例

文化生产场域的生成不仅为文化生产者提供了游戏的空间,同时也区分了文化资本的富有者和贫乏者,文化资本数量上的落差导致了符号权力关系的建立;对文化资本功效和意义的认可赋予了它足够的价值,在价值认可的基础上,文化生产者的符号权力得以合法化;而文化资本的符号特性往往会造成文化生产者本身的符号化,关于作者的各种神话被创造出来,他们的符号权力因而得到进一步强化。