基于分段电容阵列的改进型逐次逼近型ADC

为缩短高速模数转换器(ADC)中高位(MSB)电容建立时间以及减小功耗,提出了一种基于分段式电容阵列的改进型逐次逼近型(SAR)ADC结构,通过翻转小电容阵列代替翻转大电容阵列以产生高位数字码,并利用180 nm CMOS工艺实现和验证了此ADC结构。该结构一方面可以缩短产生高位数码字过程中的转换时间,提高量化速度;另一方面其可以延长大电容的稳定时间,减小参考电压的负载。通过缩小比较器输入对管的面积以减小寄生电容带来的误差,提升高位数字码的准确度。同时,利用一次性校准技术减小比较器的失配电压。最终,采用180 nm CMOS工艺实现该10 bit SAR ADC,以验证该改进型结构。结果表明,在1.8 V电源电压、780μW功耗、有电路噪声和电容失配情况下,该改进型SAR ADC得到了58.0 dB的信噪失真比(SNDR)。     

基于MATLAB的集成电路储能焊封装能量分布研究

气密性是集成电路封装中的一项重要技术指标,对于集成电路的可靠性使用具有重要作用。就气密性封装工艺中的储能焊封装技术进行了讨论,通过对储能焊设备放电过程进行分析及建模,得到了气密性焊接能量与各个工艺参数之间的关系,并利用MATLAB软件进行了模拟计算。结合具体实验,验证了理论建模及模拟的正确性,对于储能焊焊接的工艺参数设定及优化具有一定的指导意义。     

“高电压工程”课程思政教改探索与实践

针对“高电压工程”课程思政教学改革的要求,分别从教学目标、教学内容、教学方法和考核手段四个方面,挖掘课程中蕴含的思政元素,通过教学创新,有机融入思政内容,使学生不仅学到专业知识,更体会到专业内容蕴含的社会主义核心价值观。最后,通过课堂教学对“高电压工程”课程思政的改革效果进行了实践和检验,为其他电气类专业课的课程思政教学改革提供参考。     

宽阻带小型化双频带通滤波器

文中提出了一种具有宽阻带的紧凑型双频带通滤波器,它采用了折叠短路枝节负载谐振器、紧凑型微 带单元谐振器(CMRC)和阶跃阻抗谐振器结构。由于多个谐振器产生了五个可控传输零点(TZ),该滤波器实现了两个 通带之间的良好隔离度以及宽阻带特性。制作并测试了尺寸紧凑的双频带通滤波器实验样品,测试结果显示,第一通 带和第二通带的中心频率/ 插入损耗分别为0. 66 GHz/0. 8 dB 和1. 73 GHz/0. 7 dB,阻带频率高达10. 5 GHz,抑制水平 超过15 dB。     

基于超级电容的列车制动能量回收控制策略

针对列车电制动回馈能量回收与利用问题,文中通过分析列车运行特性,重点探究了列车运行过程与牵引网电压波动之间的关系。结合牵引变电所供电功率与列车用电功率动态不匹配特性,采用车载式制动能量回收利用系统的方案,提出了基于列车用电功率动态变化的超级电容充放电控制策略。该方案主要由超级电容串并联储能单元和双向DC-DC变换器组成。利用MATLAB进行建模仿真分析,结果表明,该控制策略在有效回收利用列车制动能量的同时抑制了牵引网电压波动,为列车制动能量回收与利用提供了有效的解决方案。     

Characterizations of generalized Hermite and sieved ultraspherical polynomials

A new characterization of the generalized Hermite polyno-
mials and of the orthogonal polynomials with respect to the measure
is derived which is based on a ``reversing property" of the coefficients in the corresponding recurrence formulas and does not use the representation in terms of Laguerre and Jacobi polynomials. A similar characterization can be obtained for a generalization of the sieved ultraspherical polynomials of the first and second kind. These results are applied in order to determine the asymptotic limit distribution for the zeros when the degree and the parameters tend to infinity with the same order.

     

The zeros of Faber polynomials generated by an -star

It is shown that the zeros of the Faber polynomials generated by a regular -star are located on the -star. This proves a recent conjecture of J. Bartolomeo and M. He. The proof uses the connection between zeros of Faber polynomials and Chebyshev quadrature formulas.

     

卟啉超分子化合物在分子器件中的应用

分子电子器件已成为近年来的一个研究热点，卟啉类化合物因为光敏性好、性能稳定、易于修饰等优点成为分子器件研究的理想模型化合物。本文着重介绍了它在分子器件中的最新应用进展。     

Intrinsic Surface Reaction Constant in 1-pK Model of Mg-Fe Hydrotalcite-like Compounds

The relationship among intrinsic surface reaction constant (K) in 1-pK model, point of zero net charge (PZNC) and structural charge density (σst) for amphoteric solid with structural charges was established in order to investigate the effect of σst on pK. The theoretical analysis based on 1-pK model indicates that the independent PZNC of electrolyte concentration (c) exists for amphoteric solid with structural charges. A common intersection point (CIP) should appear on the acid-base titration curves at different c, and the pH at the CIP is pHPZNC. The pK can be expressed as pK=-pHPZNC log[(1 2αPZNC)/(1-2αPZNC)], where αPZNC≡σst/eNANs, in which e is the elementary charge, NA the Avogadro‘s constant and Ns the total density of surface sites. For solids without structural charges, pK=-pHPZNC. The pK values of hydrotalcite-like compounds (HTlc) with general formula of [Mg1-xFex(OH)2](Cl,OH)x were evaluated. With increasing x, the pK increases, which can be explained based on the affinity of metal cations for H^- or OH^- and the electrostatic interaction between charging surface and H^- or OH^-.     

Synthesis and Asymmetric Enantioselective Addition of Chiral Polybinaphthyl and Polybinaphthol I.igands

Four chiral polymers P-1, P-2, P-3 and P-4 were synthesized by the polymerization of （S）-2,2＇-dioctoxy-1,1＇- binaphthyl-6,6＇-boronic acid （S-M-3） with （S）-6,6＇-dibromo-1,1＇-binaphthol （S-M-1）, （R）-6,6＇-dibromo-1,1＇- binaphthol （R-M-1）, （S）-3,3＇-diiodo-1,1＇-binaphthol （S-M-2） and （R）-3,3＇-diiodo-1,1＇-binaphthol （R-M-2） under Pd-catalyzed Suzuki reaction, respectively. All four polymers can show good solubility in some common solvents due to the nonplanarity of the polymers in the main chain backbone and flexible alkyl groups in the side chain. The analysis results indicate that specific rotation and circular dichroism （CD） spectral signals of the alternative S-S chiral polymers P-1 and P-3 are larger than those of S-R chiral polymers P-2 and P-4, but their UV-Vis and fluorescence spectra are almost similar. The results of asymmetric enantioselectivity of four polymers for diethylzinc addition to benzaldehyde indicate that catalytically active center is （R） or （S）-1, 1＇-binaphthol moieties.