高强度PAMPS-PAAm互穿网络凝胶及其溶胀性能

通过考察不同单体浓度或离子强度下凝胶的力学性能和溶胀特性,对聚2-丙烯酰胺-2-甲基丙磺酸(PAMPS)与聚丙烯酰胺(PAAm)形成的互穿网络凝胶的高强度性能和作用机理进行了研究.结果表明:PAMPS-PAAm互穿网络凝胶的力学强度对c(AMPS)存在一个最佳值(1 mol/L),且随c(AAM)的增大而显著增大(0.5～4 mol/L).当c(AMPS)=1 mol/L、c(AAM)＝4 mol/L时,互穿网络凝胶的最大抗压强度达6.46 MPa;改变凝胶体系内水的离子强度,PAMPS-PAAm凝胶在0.25 mol/kg离子强度时的抗压强度与纯水状态下相比增加了29%.     

氢元素发现史中定量推理的作用

定量推理是应用数学知识来分析解释数据、得出结论,以解决跨学科背景下的复杂问题。定量推理将数学和学科专业知识整合在一起,属于高阶思维能力。引导学生发展定量推理能力对化学学科核心素养目标的达成具有重要意义。以氢元素的发现历程为例,阐述了定量推理在科学探究过程中的关键作用。     

The entanglement properties of holographic QCD model with a critical end point

We investigated different entanglement properties of a holographic QCD(hQCD)model with a critical end point at the finite baryon density.Firstly,we considered the holographic entanglement entropy(HEE)of this hQCD model in a spherical shaped region and a strip shaped region.It was determined that the HEE of this hQCD model in both regions can reflect QCD phase transition.Moreover,although the area formulas and minimal area equations of the two regions were quite different,the HEE exhibited a similar behavior on the QCD phase diagram.Therefore,we assert that the behavior of the HEE on the QCD phase diagram is independent of the shape of the subregions.However,the HEE is not an ideal parameter for the characterization of the entanglement between different subregions of a thermal system.As such,we investigated the mutual information(MI),conditional mutual information(CMI),and the entanglement of purification(Ep)in different strip shaped regions.We determined that the three entanglement quantities exhibited some universal behavior;their values did not change significantly in the hadronic matter phase but increased rapidly with the increase in T andμin the QGP phase.Near the phase boundary,these three entanglement quantities changed smoothly in the crossover region and continuously but not smoothly at CEP;they exhibited discontinuous behavior in the first phase transition region.These properties can be used to distinguish between the different phases of strongly coupled matter.     

具连续变量的变系数偶数阶差分方程的有界振动

研究时滞差分方程解的性质在理论和应用中是非常重要的.本文借助研究离散变量的差分方程振动性的一般方法,研究了一类具有连续变量的变系数偶数阶中立型差分方程的有界解的振动性,给出了有界解振动的几个充分条件.     

Electric and magnetic screenings of gluons in a model with dimension-2 gluon condensate

Electric and magnetic screenings of the thermal gluons are studied by using the background expansion method in a gluodynamic model with gauge invariant dimension-2 gluon condensate at zero momentum. At low temperature, the electric and magnetic gluons are degenerate. With the increase of temperature, it is found that the electric and magnetic gluons start to split at certain temperature T₀. The electric screening mass changes rapidly with temperature when T > T₀, and the Polyakov loop expectation value rises sharply around T₀ from zero in the vacuum to a value around 0.8 at high temperature. This suggests that the color electric deconfinement phase transition is driven by electric gluons. It is also observed that the magnetic screening mass keeps almost the same as its vacuum value, which manifests that the magnetic gluons remain confined. Both the screening masses and the Polyakov loop results are qualitatively in agreement with the Lattice calculations.     

平衡单向分类随机效应模型中的多个异常值检验

该文研究平衡单向分类随机效应模型中多个异常值的检验问题. 在基于随机效应上的均值滑动模型下导出了似然比检验统计量, 并给出了其精确分布及水平异常值的检验过程. 在基于观测误差上的均值滑动模型下,利用得分检验统计量给出了多个异常值的检验过程.     

具连续变量的偶数阶中立型差分方程的振动性

研究具有连续变量的偶数阶中立型时滞差分方程的解的振动性,给出了有界解振动的几个充分条件.     

HL-2A装置ECRH回旋管磁场分布测量

HL-2A装置的电子回旋系统使用了俄罗斯进口的新型回旋管，在俄罗斯专家的协助下，去年将其安装完毕，并且投入了实验运行，取得了丰富的实验数据和良好的实验参数。     

具有变系数的二阶中立型差分方程的有界振动

研究一类具有连续变量的二阶中立型时滞差分方程，给出了该类方程一切有界解振动的几个充分条件.     

美托洛尔的合成工艺研究

本文以价廉易得的对羟基苯乙酸甲酯为原料,通过酚羟基苄基保护、酯键还原、甲基化、脱苄基得到关键中间体对甲氧基乙基苯酚5,再与环氧氯丙烷发生烷基化反应,最后与异丙胺反应开环得到美托洛尔。对于合成路线中的关键步骤进行了工艺优化,分步平均收率高达89.3%,6步反应总收率也高达48%。中间体及目标化合物均通过~1HNMR和~(13)CNMR确证了结构。该方法具有原料易得、合成步骤短、收率高以及易于工业化制备等优点。