大学物理课程教学设计撰写方法探讨——以绪论课为例

课程教学设计中不仅包含了课程教学内容,还蕴含了授课思路、方式与方法,以及课程思政元素的融入等因素,教学设计质量与水平是讲好一堂课的关键.本研究以绪论课为例,探讨了大学物理课程教学设计撰写思路与方法.     

利用自发布里渊散射测量液体声速

为了克服共振干涉法在液体的热力学声速和高频声速测量方面精度不高的问题, 本文建立了一种基于自发布里渊散射原理的测定液体声速的实验装置. 利用法布里-珀罗干涉仪对散射光进行扫描滤波, 数据采集卡结合光子计数器对散射光进行探测, 设计了一种散射光信息采集分析方法. 该实验方法有效的解决了传统布里渊散射方法中信号失真的问题, 显著地提升了液体声速测量精度. 对308.6–906.2 MHz内298.15 K饱和液相CCl₄声速进行了测量, 测量结果与文献值具有较好一致性. 利用法布里-珀罗干涉仪周期性扫描的滤波原理, 通过在测量得到的布里渊频移上加减整数倍个自由波谱区, 得到了更大频率的波谱信息, 进而设计一种测定介质高频声速的方法. 对CCl₄在5406.1–5521.0 MHz频段内的声速进行了测量. 实验结果显示, CCl₄的热力学声速随频率无明显变化, 而高频声速随频率的增大呈增大趋势且远大于热力学声速, 证实CCl₄具有色散现象.     

A NOTE ON THE COMPLEX OSCILLATION OF NONHOMOGENEOUS LINEAR DIFFERENTIAL EQUATIONS WITH TRANSCENDENTAL ENTIRE COEFFICIENTS

ＡＮＯＴＥＯＮＴＨＥＣＯＭＰＬＥＸＯＳＣＩＬＬＡＴＩＯＮＯＦＮＯＮＨＯＭＯＧＥＮＥＯＵＳＬＩＮＥＡＲＤＩＦＦＥＲＥＮＴＩＡＬＥＱＵＡＴＩＯＮＳＷＩＴＨＴＲＡＮＳＣＥＮＤＥＮＴＡＬＥＮＴＩＲＥＣＯＥＦＦＩＣＩＥＮＴＳＧａｏＳｈｉａｎ；＆ＷａｎｇＳｈｅｎ...     

新型含羧戊基不对称五甲川菁染料的合成及蛋白标记

以磺酸基苯肼和7-甲基-8-氧代壬酸为原料合成了2,3-二甲基-3-羧戊基-3H-吲哚-5-磺酸;以2,3,3-三甲基-3H-吲哚-5-磺酸和1,3-丙磺酸内酯为原料合成了1-磺酸丙基-2,3,3-三甲基-3H-吲哚-5-磺酸;然后通过半菁合成法合成了一种新型水溶性不对称五甲川吲哚菁染料(Cy5)。产物经C18反相硅胶柱分离,收率57%,其结构经1H NMR、HRMS进行确证。并检测了目标化合物的光谱性质,初步探讨了其在生物标记方面的应用。染料具有良好的水溶性和光稳定性,水溶液的最大紫外吸收波长和最大荧光发射波长分别为646和666 nm,荧光量子产率为0.2,用n(活化菁染料)∶n(牛血清蛋白)=2∶1标记蛋白,D/P值为1.56。     

线型分子势能函数及第二维里系数计算

本文以两中心的Lennard—Jones（2CLJ）流体为研究对象,通过引入与温度相关的势能参数,提出了改进型的2CLJDQP势能函数模型。应用此模型计算了乙烷（C2H6）、六氟乙烷（C2F6）、氟甲烷（CH3F）、氯甲烷（CH3C1）、1,1,1-三氟乙烷（CH3CF3）、二氟乙烷（CH3CHF2）的第二维里系数,较...     

甲烷部分氧化制合成气:载体及助剂对Ni系催化剂活性的影响

 采用浸渍法制备了Ni系催化剂,并用程序升温还原和X射线衍射技术对催化剂进行了表征,用固定床微反装置考察了催化剂的催化活性．活性考察结果表明,在Ni担载量为8％的Ni／γ－Al2O3,Ni／δ－Al2O3,Ni／θ－Al2O3和Ni／α－Al2O3四种催化剂上,甲烷部分氧化制合成气反应的活性及产物选择性存在着明显的差异．在770℃下,甲烷转化率及CO和H2的选择性按Ni／γ－Al2O3＜Ni／δ－Al2O3＜Ni／θ－Al2O3≈Ni／α－Al2O3顺序排列．在相同的条件下,加入适量的CeO2助剂后,Ni／γ－Al2O3和Ni／δ－Al2O3上的反应活性和选择性显著提高,而Ni／θ－Al2O3和Ni／α－Al2O3上的活性和选择性却变化不大．同时,表征结果显示,Ni易与γ－Al2O3形成镍铝尖晶石NiAl2O4,加入CeO2助剂能有效地抑制该组分的生成,而Ni／α－Al2O3样品中未发现NiAl2O4．因此,不同Ni／Al2O3催化剂体系上的反应活性及选择性的差异可归结为不同结构Al2O3载体的性质不同,及CeO2对抑制镍铝尖晶石生成的效果不同．     

Modified 2CLJDQP model and the second virial coefficients for linear molecules

A modified form of 2CLJDQP potential model is proposed to calculate the second virial coefficients of two-center Lennard-Jones molecules. In the presented potential model, the potential parameters σ and ε are considered as the temperature-dependent parameters in the form of hyperbolical temperature function based on the theory of temperaturedependent potential parameters. With this modified model, the second virial coefficients of some homonuclear molecules（such as O2, Cl2, CH3CH3, and CF3CF3） and heteronuclear molecules（such as CO, NO, CH3 F, CH3 Cl, CH3CF3,CH3CHF2, and CF3CH2F） are calculated. Then the Lorentz–Berthelot mixing rule is modified with a temperaturedependent expression, and the second virial coefficients of the heteronuclear molecules（such as CH3 F, CH3 Cl, and CH3CF3） are calculated. Moreover, CO2 and N2O are also studied with the modified 3CLJDQP model. The calculated results from the modified 2CLJDQP model accord better with the experimental data than those from the original model.It is shown that the presented model improves the positive deviation in low temperature range and negative deviation in high temperature range. So the modified 2CLJDQP potential model with the temperature-dependent parameters can be employed satisfactorily in large temperature range.     

Bandgap evolution of Mg3N2 under pressure: Experimental and theoretical studies

Wide bandgap semiconductors are crucially significant for optoelectronic and thermoelectric device applications. Metal nitride is a class of semiconductor material with great potential. Under high pressure, the bandgap of magnesium nitride was predicted to grow. Raman spectra, ultra-violet-visible (UV-Vis) absorption spectra, and first-principles calculations were employed in this study to analyze the bandgap evolution of Mg₃N₂. The widening of the bandgap has been first detected experimentally, with the gap increasing from 2.05 eV at 3 GPa to 2.88 eV at 47 GPa. According to the calculation results, the enhanced covalent component is responsible for the bandgap widening.     

磷矿的超声分解—磷酸的超声萃取研究

磷酸是化学工业上一种重要的无机酸,通过它可以制成一系列重要的产品。例如,用于肥料生产可制得磷酸钙、重过磷酸钙、磷