大学英语阅读与写作教学评价量规的制定与应用

评价量规已经成为语言教学评价中一种有效的工具,它有助于帮助教师向学生阐明学习目标和任务,并向学生提供有效的反馈信息.本文着重介绍了大学英语教学中阅读和写作的评价量规的制定,并阐述了在制定量规时应该遵守的原则.     

丙烯酰胺基交联聚合物微球的制备及其对钻井液性能的影响

为揭示水分散聚合方法制备的丙烯酰胺基交联聚合物微球的结构特征及其对钻井液性能的影响规律,以硫酸铵水溶液为反应介质,丙烯酰胺(AM)、丙烯酸(AA)、甲基丙酰氧乙基三甲基氯化铵(DMC)为共聚单体,2,2-偶氮二(2-甲基丙基咪)二盐酸盐为引发剂,N,N'-亚甲基双丙烯酰胺复配物为交联剂制备了丙烯酰胺基交联聚合物微球。采用红外光谱、粒度分析等方法表征了交联聚合物微球的结构,研究了丙烯酰胺基交联聚合物微球对钻井液性能的影响。结果表明,交联聚合物微球的合成工艺条件对产物的降滤失性影响较小,但对产物在钻井液中的增黏作用影响显著。随AM和交联剂加量增加,聚合物微球对钻井液的增黏作用增强;存在对钻井液增黏作用最小的引发剂加量和AA与DMC摩尔比。采用水分散聚合方法可制备出平均粒径8.04μm(粒径范围2.43数53.72μm)的丙烯酰胺基交联聚合物微球。该交联聚合物微球对钻井液具有显著的降滤失作用和一定的增黏作用,耐温性能优良,150℃高温老化不会降低交联聚合物微球的降滤失作用,但可降低对钻井液的增黏作用,减小其对钻井液流变性的影响。     

Theoretical Study of Optically Pumped NH3 Far-Infrared Laser in Vibrational Ground State

In this paper, the density matrix equation of three-level system for far-infrared (FIR) Raman transition in vibrational ground state was solved. By means of iteration method and numerical calculation, the spectral characteristics of NH₃ molecules FIR laser with TEA CO₂-10R(14) laser pumping was studied theoretically. The theoretical result would help us to understand the physical mechanism of optically pumped molecular gases FIR laser with ground-state reversal transition.     

Stoichiometry Control for the Tuning of Grain Passivation and Domain Distribution in Green Quasi‐2D Metal Halide Perovskite Films and Light‐Emitting Diodes

Quasi‐2D metal halide perovskite films are promising for efficient light‐emitting diodes (LEDs), because of their efficient radiative recombination and suppressed trap‐assisted quenching compared with pure 3D perovskites. However, because of the multidomain polycrystalline nature of solution‐processed quasi‐2D perovskite films, the composition engineering always impacts the emitting properties with complicated mechanisms. Here, defect passivation and domain distribution of quasi‐2D perovskite films prepared with various precursor compositions are systematically studied. As a result, in perovskite films prepared from stoichiometric quasi‐2D precursor compositions, large organic ammonium cations function well as passivators. In comparison, precursor compositions of simply adding large organic halide salt into a 3D perovskite precursor ensure not only the defect passivation but also the effective formation of quasi‐2D perovskite domains, avoiding unfavorable appearance of low‐order domains. Quasi‐2D perovskite films fabricated with a well‐designed precursor composition achieve a high photoluminescence quantum yield of 95.3% and an external quantum efficiency of 14.7% in LEDs.     

Layered Silicon‐Based Nanosheets as Electrode for 4 V High‐Performance Supercapacitor

Silicon‐based materials have shown great potential and been widely studied in various fields. Unlike its unparalleled theoretical capacity as anodes for batteries, few investigations have been reported on silicon‐based materials for applications in supercapacitors. Here, an electrode composed of layered silicon‐based nanosheets, obtained through oxidation and exfoliation, for a supercapacitor operated up to 4 V is reported. These silicon‐based nanosheets show an areal specific capacitance of 4.43 mF cm^?2 at 10 mV s^?1 while still retaining a specific capacitance of 834 µF cm^?2 even at an ultrahigh scan rate of 50 000 mV s^?1. The volumetric energy and power density of the supercapacitor are 7.65 mWh cm^?3 and 9312 mW cm^?3, respectively, and the electrode can operate for 12000 cycles in a potential window of 4 V at 2 A g^?1, while retaining 90.6% capacitance. These results indicate that the silicon‐based nanosheets can be a competitive candidate as the supercapacitor electrode material.     

基于Arnold变换的量子图像混沌加密方法

在确保量子图像密码算法安全的基础上,为进一步优化解密图像质量及计算复杂度,该文提出一种基于Arnold变换的量子图像混沌加密方案。方案使用量子细胞神经网络产生的混沌信号来控制量子Arnold变换、量子交换(SWAP)和量子控制非操作(CNOT),然后将这些操作作用于量子明文图像中以获得相应的密文图像。研究结果表明：所提量子灰度图像加密方法具有高安全性、高解密图像质量及低计算复杂度的特点。     

立足基础面向学科构建电路理论课程的立体化教学体系

本文详细介绍了教育部2002年启动教学质量工程以来,我校电路理论课程的教学改革建设的成效,包括电路理论课程的立体化教学体系的建立、相关课程的立体化教材的建设、实验实践教学的强化、教学方法的改进和具体的实践效果。     

军用软件鉴定定型标准化工作方法

结合最新版装备试验鉴定指导性文件TE-BTBA-004-2021《装备状态鉴定工作指南》、TE-BTBA-006-2021《装备列装定型工作指南》及TE-BTBC-002-2021至TE-BTBC-028-2021《装备鉴定定型文件编制指南》等,阐述军用软件鉴定定型阶段的主要工作,阐明军用软件鉴定定型标准化工作在定型装...     

加权系数平均法改进的小波域LMMSE信道估计算法

针对传统LMMSE算法需要知道信道特性的问题,提出了一种加权系数平均法改进的小波域LMMSE信道估计算法.运用离散小波变换对LS初始估计和预滤波处理后的信号实行阈值量化去噪处理,然后结合时域信道能量分布的稀疏性特征,利用加权系数平均法求出各子载波的频域响应,从而克服了传统LMMSE算法需要预先知晓信道统计特性的缺陷.对算法的BER和MSE性能进行实验仿真,结果表明:文中所提改进算法的信道估计整体性能显然会更优于LS、SVD-LMMSE以及加权平均改进后的LMMSE算法.另外,在信噪比较低且信道统计特性未可知的状况下,文中算法要优于传统的LMMSE算法,并能够较好地降低噪声的影响,有效提升信道估计的精确度.