以学生为主体的有机实验教学探讨

有机实验课的教学效果直接影响到化学专业的质量问题,针对目前存在的一些问题,指导教师在教学中应树立"以学生为主体"的教学理念,重视实验课前预习工作;加强师资力量,强化指导环节;把有价值的相关信息融入课堂教学,更好地培养学生的综合实验技能。     

运用虚拟仿真与多媒体教学相结合的材料力学实验教学改革

材料力学实验是一门重要的工科专业基础实验课.针对原有材料力学实验课中存在的学生预习不充分、实验操作时间较少等问题,运用虚拟仿真技术和多媒体技术对材料力学试验教学进行改革.原有的材料力学成绩考核方式只注重实验报告成绩,缺少了对实验预习和实验操作环节的考核.通过对考核方式的完善,使实验考核成绩由预习成绩、操作成绩和报告成绩三个部分组成.此次实验教学改革增强了学生的实验兴趣,提升了学生的实验操作能力,取得了较好的教学效果.     

基于科研能力培养的地方高校植物生理学实验教学改革

目前地方高校植物生理学实验课教学主要是基础验证性实验,同时课堂中"注入式"教学方法不利于激发学生学习热情和培养学生动手与科研思维能力。针对这些问题,对植物生理实验课教学进行了改革,将单一的小实验进行有机融合,使之成为综合性实验,从而提高学生的知识系统性、实验主动性以及科研创新能力。让学生参与实验准备环节以提高学生的动手能力,在课堂中运用启发式教学以提高学生学习兴趣和教学效果。此外,将实验报告改革为研究论文,从而提高学生的科研论文写作能力。     

生物专业基础化学实验课教学效果评价体系的研究与实践

科学的实验教学效果评价体系是确保实验课教学质量的核心环节.本文分析了我院生物专业基础化学实验课的教学内容、实验考核模式现状及问题,初步探索了以学生为本的、与生物专业基础化学实验课教学目标相适应的、可操作的实验教学效果评价方法,构建了"基础实验+综合实验+设计实验"为内容、"平时考核+期末考核"并重的综合实验教学效果评价体系.实践证明,新的评价体系能有效促进学生主动学习的兴趣和实验效果,利于教师对教学效果的检查,能较全面客观地评价学生实验课的成绩,取得了一定的教学效果.     

对比式教学方法在纸色谱实验课上的实践

在"纸色谱分离几种氨基酸"实验课上采用对比式教学法,改变以往教师讲解、学生照方取药的传统实验模式,让学生做实验课堂的主角,教师辅助学生完成实验,学生通过配制不同展开剂,亲身实践不同组实验结果,主动探究实验原理,由被动学习转为主动学习,明显提高了学生实验课的积极性,培养了学生分析问题、解决问题的能力及创新意识,使实验课教学环节充满生趣。     

“临床血液学检验”实验课教学改革与实践

医学检验专业由五年制改为四年制,为了适应教改需求,使实验课教学跟进理论教学,对"临床血液学检验"实验课进行了一系列教学改革,包括实验课教学方法的改革,调整实验课教学内容,配备数码互动实验室,对实验课教学环节进行改革等,目的是培养学生的独立思考能力及动手能力,让学生早期接触临床,以适应实习及工作学习的需要,培养出新一代适应社会需要的四年制检验技师人才。     

“临床检验基础”实验课教学改革与实践

为了适应医学检验专业四年制的教学改革,使实验课教学更具实用性和操作性,通过对"临床检验基础"实验课的教学改革,包括实验课教学方法的改革,调整实验课教学内容,购置自动化检验仪器,对实验课教学环节进行改革等,目的是培养学生的独立思考能力及动手能力,让学生早期接触临床,以适应实习及工作学习需要,培养出新的一代适应社会需要的检验技师人才。     

以问题为基础教学法在运动解剖学实验课教学中的应用

将以问题为基础教学法应用于运动解剖学实验课教学,结果表明,与传统教学方法相比,以问题为基础教学法能有效地提高学生成绩,提高学生学习兴趣,激发学习动机,提高学习效率,活跃课堂氛围,提高学生发现、解决问题的能力,从而有利于学生对知识的掌握.并指出使用以问题为基础教学法需要注意的问题为:教师对问题的选择要有针对性;教师要正确处理"收"与"放"的关系;教学过程要做到充分交流.     

精品实验项目教学的实践与体会

结合河北大学精品实验教学改革的实践,总结了目前大学生物理化学实验课学习存在的主要问题。以物理化学精品实验项目"溶液表面张力的测定"的设立为例,分别从教学方案设计、实验内容的合理构建与预习资料微课的制作、课堂教学的实施等几个方面探讨了如何在精品实验教学环节中丰富教学内容、优化教学效果,从而激发学生实验课前预习的主动性,提高学生实验兴趣,全面培养学生的综合素质。     

“循进式”高中物理实验教学实践与思考

物理新课程改革对物理实验教学提出了更高的要求。如何更好地进行高中物理实验教学,提高学生的实验能力,是物理教师需要思考的问题。为此,我们在实验课教学中采用"循进式"教学方法,力求提高学生的实验能力。     

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…     

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.     

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.     

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.     

Effect of proton irradiation on structure relaxation of Zr<Subscript>41.5</Subscript>Ti<Subscript>14.9</Subscript>Cu<Subscript>12.6</Subscript>Ni<Subscript>10.5</Subscript>Be<Subscript>20.4</Subscript> bulk metallic glass

Effects of proton irradiation on structure re-laxation of Zr_(41.5)Ti_(14.9)Cu_(12.6)Ni_(10.5)Be_(20.4) bulk metallic glass areinvestigated by means of X-ray diffraction, differential scan-ning calorimetric and electronic resistance measurements.The results show that, at 203 K, the structure ofZr_(41.5)Ti_(14.9)Cu_(12.6)Ni_(10.5)Be_(20.4) bulk metal glass is relaxed obvi-ously by proton irradiation with the energy and the dosebeing of 160 keV and 1.65×10~(16) ions/cm~2, respectively. How-ever, Zr_(41 .5)Ti_(14.9)Cu_(12.6)Ni_(10.5)Be_(20.4) bulk metallic glass becomesmore steady amorphous state under two conditions, one isthat the energy and the dose are 160 keV and 1.1×10~(15)ions/cm~2, respectively. Another is that the energy and thedose are 120 keV and 6.5×10~(15) ions/cm~2, respectively.     

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.     

Electro-deoxidation of V<Subscript>2</Subscript>O<Subscript>3</Subscript> in molten CaCl<Subscript>2</Subscript>-NaCl-CaO

The electro-deoxidation of V₂O₃ precursors was studied. Experiments were carried out with a two-terminal electrochemical cell, which was comprised of a molten electrolyte of CaCl₂ and NaCl with additions of CaO, a cathode of compact V₂O₃, and a graphite anode under the potential of 3.0 V at 1173 K. The phase constitution and composition as well as the morphology of the samples were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). 3 g of V₂O₃ could be converted to vanadium metal powder within the processing time of 8 h. The kinetic pathway was investigated by analyzing the product phase in samples prepared at different reduction stages. CaO added in the reduction path of V₂O₃ formed the intermediate product CaV₂O₄.     

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.     

One-pot synthesis of PVP-coated Ni<Subscript>0.6</Subscript>Fe<Subscript>2.4</Subscript>O<Subscript>4</Subscript> nanocrystals

Novel poly(N-vinyl-2-pyrrolidone) (PVP)-coated nickel ferrite nanocrystals were prepared by simultaneously pyrolyzing nickel(II) acetylacetonate (Ni(acac)₂) and iron(III) acetylacetonate (Fe(acac)₃) in N-vinyl-2-pyrrolidone (NVP). The PVP coating was formed in situ through polymerization of NVP. The crystalline structure of the resultant nickel ferrite was analyzed by high-resolution transmission electron microscopy, electron diffraction patterns, and powder X-ray diffraction. In addition, the valence state of Ni and the metal contents of Ni and Fe in different valence states were analyzed by X-ray photoelectron spectroscopy (XPS), atomic absorption and the phenanthroline method. The surface coating layer of PVP and its binding states were characterized by Fourier transform infrared spectroscopy in combination with XPS. Colloidal stability experiments revealed that the nanocrystals could be dispersed well in both phosphate-buffered saline and Dulbecco’s Modified Eagle Medium.