光学工程专业研究生“现代光学实验”的教学改革

简要介绍南开大学光学工程专业研究生"现代光学实验"课程的教学现状,对实验教学内容及授课模式进行分析。针对课程中存在的问题,提出几点改革方案:提高教学效率的"三步走教学"方法;为提升教学质量提倡与时俱进的教学内容;为强化学生科研思维及动手能力增加自主实验。同时对研究生实验教学改革进行了初步的探索与实践,取得了显著成效。     

“研讨式”教学在军校研究生教学中的应用

研究生具有不同于本科生的身心特点和培养目标,决定研究生的课程教学应采用"研讨式"教学方式。"研讨式"教学的实施,需要教师精心准备和组织,涉及专题划分和团队组建、进度安排、课程报告与讨论、撰写课程论文等具体环节。"研讨式"教学方式对于研究生综合素质与能力的培养,实现研究生培养目标具有重要而直接的意义。     

基于虚拟仿真实验的"应用光学"工程教育实践

"应用光学"是光学相关专业的一门学科基础课或专业基础课.秉承工程教育以成果导向教育的主要理念,将虚拟仿真实验应用于"应用光学"课程的工程化教学实践,利用仿真计算软件提升授课内容中原理的可视化效果,对无法实际展示的实验进行补充,对无法展示的光学系统的内部结构进行直观的展示.在此基础上,结合科研中的工程实践案例,开展了光学...     

统计学硕士研究生培养现状调查与分析

通过问卷调查的方式研究统计学研究生的培养现状,主要从课程设置情况、授课方式、科研氛围三个方面进行考察,结果显示:课程设置较好但仍需改进,专业硕士研究生对于课程设置最不满意;授课方式方面,"填鸭式"教学最受欢迎,部分学生支持讨论式教学,整体授课方式需要改进;高校科研氛围较差,专业硕士比例较高,统计专业士研究生参与课题数目偏少,科研成果较少.针对统计学硕士培养的不足,提出对策建议.     

有关研究生课程教学中研讨式教学模式的探讨

研讨式教学模式是研究生课程教学改革的积极尝试,它使提高研究生独立科研能力、创新能力、合作研究能力的培养目标落实到研究生课程学习中。本文通过介绍研讨式教学模式的基本理念,并结合研讨式教学模式特点探讨一下研讨式教学模式在实践中需要注意的主要问题。     

非线性光学效应在光纤通信中的应用研究

为了研究非线性光学效应在光纤通信中的应用,首先阐述了非线性光学的定义,探讨了非线性光学在光纤通信方面的应用发展．指出其研究展望．着重数值模拟了非线性光学效应在光纤通信中用作光纤拉曼放大器时的物理过程．结果表明：基于Chraplyvy模型能够较好地模拟出受激拉曼散射作为光纤拉曼放大器原理的过程．并且其程序运行效率高于采用洛仑兹模型．结论与文献相比有新的进展,为非线性光学的进一步理论、实验和应用研究提供了参考．     

启发式思维驱动的研究生算法课程在线教学探索

受新冠肺炎疫情影响,2020年春季学期的研究生课程由线下授课全面转为线上教学。该文针对研究生算法设计与分析课程特点,分析当前存在的问题,探索算法课程在线教学模式的创新与改革,在课程基础理论统一框架下,从教学内容、教学过程、教学考核评估等方面设计多元化的在线教学方案,全面融入启发式和研讨式教学模式,总结了研究生在线课程教学的经验和不足。     

孤子脉冲在光子晶体光纤中的传播特性研究

根据光脉冲在光子晶体光纤中传播的非线性薛定谔方程,分析了孤子传播基本原理,给出了光脉冲在光子晶体光纤中色散和非线性效应的表达式,对非线性薛定谔方程进行归一化处理并求解,获得光子晶体光纤中基态孤子解.在远大于光纤零色散波长区域,使色散和非线性效应达到平衡,在光子晶体光纤中就可以得到稳定的光学孤子.光子晶体光纤中产生的孤子可以作为光孤子通信的载波,是光子晶体光纤中高次谐波产生的泵浦源.     

探究式小班教学模式的浅析与实践

教学模式的创新是提高大学课堂教学质量的一种重要方法,高校的探究式小班教学是一种新的教学模式。该文对教学模式中涉及的4个主要问题进行了浅析,并介绍了一种合作式"大班授课小班研讨"的探究式小班教学模式。该教学模式非常适合于承担同一门课程的大班教学的教师开展"大班授课小班研讨"的需要。实践表明,该教学模式在实际教学中取得了良好的教学效果。     

新一代光纤智能传感网技术进展

新一代光纤智能传感网是一项涵盖领域较为广泛的综合性技术,主要包括微结构光纤传感、基于非线性光学散射的光纤传感、基于光纤扰动的光纤传感、传感网的优化及应用技术四个方面。燕山大学、天津大学研制了不同类型的光子晶体光纤传感器,可用于生物化学方面检测。中国计量学院、南京大学开展了基于非线性光学散射的光纤系统研究,并在实际工程中得到应用。复旦大学、天津大学、上海理工大学针对光纤扰动的理论、算法等方面进行了研究。天津大学开展了光纤传感网优化及应用的研究,并在实际中得到应用。该文简要介绍了上述科研机构在光纤智能传感网技术方面取得的进展,为广大科研工作者进行相关研究提供参考。     

盾构机密封舱渣土非线性本构模型参数识别

根据密封舱改性渣土的三轴压缩实验数据,建立了基于优化方法的Duncan-Chang双曲线本构模型参数反演方法。为了解决参数识别反问题解的不稳定性问题,在Gauss-Newton优化迭代算法的基础上,提出了正则化参数反演方法。实际应用结果表明,所提出的反演方法具有较快的收敛速度和较强的鲁棒性,预测的实验模型变形与实验值吻合较好。     

Electrochemical properties of LiNi<Subscript>0.5</Subscript>Mn<Subscript>1.3</Subscript>Ti<Subscript>0.2</Subscript>O<Subscript>4</Subscript>/Li<Subscript>4</Subscript>Ti<Subscript>5</Subscript>O<Subscript>12</Subscript> cells

Spinel compounds LiNi_0.5Mn_1.3Ti_0.2O₄ (LNMTO) and Li₄Ti₅O₁₂ (LTO) were synthesized by different methods. The particle sizes of LNMTO and LTO are 0.5–2 and 0.5–0.8 μm, respectively. The LNMTO/LTO cell exhibits better electrochemical properties at both a low current rate of 0.2C and a high current rate of 1C. When the specific capacity was determined based on the mass of the LNMTO cathode, the LNMTO/LTO cell delivered 137 mA·h·g⁻¹ at 0.2C and 118.2 mA·h·g⁻¹ at 1C, and the corresponding capacity retentions after 30 cycles are 88.5% and 92.4%, respectively.     

Preparation of Al<Subscript>72</Subscript>Ni<Subscript>8</Subscript>Ti<Subscript>8</Subscript>Zr<Subscript>6</Subscript>Nb<Subscript>3</Subscript>Y<Subscript>3</Subscript> amorphous powders and bulk materials

Amorphous Al₇₂Ni₈Ti₈Zr₆Nb₃Y₃ powders were successfully fabricated by mechanical alloying. The microstructure, glass-forming ability, and crystallization behavior of amorphous Al₇₂Ni₈Ti₈Zr₆Nb₃Y₃ powders were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). The isothermal crystallization kinetics was analyzed by the Johnson–Mehl–Avrami equation. In the results, the supercooled liquid region of the amorphous alloy is as high as 81 K, as determined by non-isothermal DSC curves. The activation energy for crystallization is as high as 312.6 kJ·mol?1 obtained by Kissinger and Ozawa analyses. The values of Avrami exponent (n) imply that the crystallization is dominated by interface-controlled three-dimensional growth in the early stage and the end stage and by diffusion-controlled two- or three-dimensional growth in the middle stage. In addition, the amorphous Al₇₂Ni₈Ti₈Zr₆Nb₃Y₃ powders were sintered under 2 GPa at temperatures of 673 K and 723 K. The results show that the Vickers hardness of the compacted powders is as high as Hv 1215.     

Acid etching process for fabrication of Bi2Sr2CaCu2O8＋x stack

We adopted a new method, acid etching process, to fabricate the intrinsic Josephson junctions based on the Bi2Sr2CaCu2O8 x single crystals. By soaking the crystals into the dilute hydrochloric acid, we fabricated a junction stack successfully, and meantime made the surrounding area insulated. A certain concentration of hydrochloric acid was used to maintain the roughness of the modified layer. The cur-rent-voltage characteristic was achieved through the four terminal measurement. We could control the junctions' number by changing the concentration and the soaking time. We also found that the thick-ness of the stack was equal to the average height of the insulation layer. Such a simple, convenient and controllable fabrication method with a high yield might widen the applications of the intrinsic Joseph-son junctions.     

基于遗传算法的带附加气室空气悬架多目标优化

以带附加气室的空气弹簧悬架为研究对象,按照物理模型建立带附加气室空气弹簧的数学模型,考虑到空气弹簧刚度的非线性,将该模型以空气弹簧非线性力的形式直接引入到1/4车辆模型。以提高车辆平顺性、行驶安全性及操纵稳定性的综合性能为目标,以附加气室容积为优化变量,设计带附加气室空气悬架的多目标优化模型;考虑到悬架性能各指标量在量纲与量级上的差异,对各指标量进行统一化处理,并采用线性加权和法将多目标函数转化为单目标评价函数。在MAT-LAB/Simulink中搭建系统仿真模型,采用遗传优化算法对典型工况下的最优附加气室容积进行寻优。优化结果表明,优化附加气室容积能有效提高悬架的综合性能,降低车身加速度、悬架动行程,但轮胎动载荷有所增加。     

Kinetic parameters of oscillating reaction of amino acid- BrO3^——Mn^2＋-H2SO4-acetone system

In the previous papers[1—3], the oscillating reactionusing amino acids as organic substrates was studied. Inorder to obtain information about the kinetic parameters ofoscillating reaction of amino acids in amino acid- BrO3 - ?Mn2 -H2SO4-acetone sy…     

Rolling-induced microstructure change in Zr_（65）Al_（7.5）Ni_（10）Cu_（12.5）Ag_5 bulk metallic glass

The microstructures and free-volume evolutions of as-cast and pre-annealed Zr65Al7.5Ni10Cu12.5Ag5 bulk metallic glasses during rolling deformation have been investigated. No phase transformation is detected in the as-cast/rolled specimen. However,the structural stability of the glass against plastic deformation is worse after pre-annealing,indicated by nanocrystallization in preannealed/rolled specimens with large deformation degrees. Moreover,with increasing deformation degree,the free-volume content in a pre-annealed/rolled specimen increases at a lower average rate than that in an as-cast/rolled specimen.     

Synthesis, Characterization and Calorimetry of Ni（C4H8N2O3）2Cl2

A coordination complex was synthesized from NiCl2 and dipeptide glycylglycine（GG）. It was characterized by element analysis, NMR and TG methods, and then was determined to be Ni（C4HsN2O3）2Cl2. Using an isoperibolic reaction calorimeter, the standard molar enthalpy of formation of Ni（GG）2Cl2（solid） has been determined to be -（1 674.66±2.02） kJ · mol^-1 at 298.15 K.     

Work toughening effect in Zr_（41）Ti_（14）Cu_（12.5）Ni_（10）Be_（22.5） bulk metallic glass

Work hardening is a well-known phenomenon occurring in crystalline metals during deformation,which has been widely used to increase the strength of metals although their ductility is usually reduced simultaneously. Here we report that the plastic strain of Zr41Ti14Cu12.5Ni10Be22.5 (at.%) bulk metallic glasses has been increased from 0.3% for the as-cast sample to 2.5%-8.0% for samples that have experienced pre-deformation under constrained conditions. The pre-deformed glassy alloys possess more free volume and abundant introduced shear bands,which are believed to promote the activation of shear bands in post-deformation and result in an increase in plasticity. The orientation of the pre-introduced shear bands relative to the loading direction will affect the deformation behavior of pre-deformed samples. The present results show that pre-deformation of this glassy alloy will result in work toughening. This work toughening effect can be removed by isothermal annealing at a sub-Tg (glass transition) temperature,which causes annihilation of free volume and healing of shear bands.     

Mutagenesis of Ser24 of Cytochrome b559 α Subunit Affects PSII Acitivies in Chlamydomonas reinhardtii

In order to study the functions of cytochrome b559 (Cyt b559) in photosystem two (PSII) activity, mutant S24F of Chlamydomonas reinhardtii was constructed using site directed mutagenesis, in which Serine24 (Ser24) locating downstream of Histidine23 (His23) in α subunit of Cyt b559 was replaced by Phenylalanine (Phe). Physiological and biochemical analysis showed that mutant S24F could be grown photoautotrophically or photoheterotrophically. However, their growth rate was slower either on HSM or TAP medium than that of the control; Analysis of PSII activity revealed that its oxygen evolution was about 71% of wild type (WT); The Photochemical efficiency of PSII (Fv/Fm) of S24F was reduced 0.23 compared with WT; S24F was more sensitive to strong light irradiance than the wild type; Furthermore, SDS-PAGE and Western-blotting analysis indicated that the expression levels of α subunit of Cyt b559, LHCII and PsbO of S24F were a little less than those of the wild type. Overall, these data suggests that Ser24 plays a significant role in making Cyt b559 structure maintain PSII complex activity of oxygen evolution although it is not directly bound to heme group.