水杨醛缩邻氨基苯酚的合成及铅荧光反应的研究和应用

合成了荧光试剂水杨醛缩邻氨基苯酚,在NH4Cl-NH3·H2O缓冲溶液介质中,铅离子能使其荧光强度增强,荧光增强的程度随铅离子含量的增加而增大.据此建立了测定痕量铅离子的直接荧光分析方法.并研究此试剂与铅荧光反应的最佳条件,在λex/λem=386/502nm处,铅离子含量在0.0-200.0μg·L-1范围内与△F呈良好的线性关系,方法的检出限为1.62μg·L-1.该方法操作简便快速,具有极高的灵敏度.用于蓄电池废水中铅含量的测定,结果与火焰原子吸收光谱法基本一致,效果令人满意.     

富氧条件下乙炔选择催化还原NOx

Acetylene as a reducing agent of metal exchanged HY catalysts, for selective catalytic reduction of NO in the reaction system of 0.16% NO, 0 （C2H2-SCR） was investigated over a series 08% C2H2, and 9.95% O2 （volume percent） in He. 75% of NO conversion to N2 with hydrocarbon efficiency about 1.5 was achieved over a Ce-HY catalyst around 300 ℃. The NO removal level was comparable with that of selective catalytic reduction of NOx by C3H6 reported in literatures, although only one third of the reducing agent in carbon moles was used in the C2H2-SCR of NO. The protons in zeolite were crucial to the C2H2-SCR of NO, and the performance of HY in the reaction was significantly promoted by cerium incorporation into the zeolite. NO2 was proposed to be the intermediate of NO reduction to N2, and the oxidation of NO to NO2 was rate-determining step of the C2H2-SCR of NO over Ce-HY. The suggestion was well supported by the results of the NO oxidation with O2, and the C2H2 consumption under the conditions in the presence or absence of NO.     

Atomistic simulation of kink structure on edge dislocation in bcc iron

Based on the general theory of dislocation and kink, we have constructed the three kink models corresponding to the 1/2 （111）{011} and 1/2 （111）{112} edge dislocations （EDs） in bcc Fe using the molecular dynamics method. We found that the geometric structure of a kink depends on the type of ED and the structural energies of the atom sites in the dislocation core region, as well as the geometric symmetry of the dislocation core and the characteristic of the stacking sequence of atomic plane along the dislocation line. The formation energies and widths of the kinks on the 1/2 （111）{011} and 1/2 （111）{112} EDs are calculated, the formation energies are 0.05eV and 0.04eV, and widths are 6.02b and 6.51b, respectively （b is the magnitude of the Burgers vector）. The small formation energies indicate that the formation of kink in the edge dislocation is very easy in bcc Fe.     

杂质P对α-Fe中刃型位错上扭折电子结构的影响

利用离散变分方法和DMol方法，研究了P对bcc Fe中［100］(010)刃型位错上扭折电子结构的影响，计算了杂质偏聚能、原子间相互作用能、电荷密度及态密度.计算结果表明：微量P引入体系后，电荷发生了重新分布，P原子得到电子，其周围Fe原子失去电子，由于P原子的3p轨道与近邻Fe原子的3d4s4p轨道之间杂化，使P原子与近邻Fe原子间有较强的相互作用，不利于扭折的迁移，使位错运动受阻，有利于材料强度的提高.同时，杂质P原子与基体原子间的成键主要是d，p轨道起作用，使得它们之间的成键有较强的方向性，有可能     

基于“学习金字塔理论”的物理化学实验教学模式改革实践

介绍了东北林业大学物理化学实验课程教学中基于"学习金字塔理论"进行教学模式改革实践的情况。在实施实验教学过程中,通过增加"学生通过在线实验视频预习""学生为学生讲解实验""操作前学生小组讨论"和"操作后学生小组总结讨论"等学习环节,建立了一种有效的"以学生为中心"的实验教学模式,促进了学生综合素质和创新能力的培养,取得了良好的教学效果。     

镍基单晶高温合金相界面错配位错网络的演化

运用分子动力学方法,研究了镍基单晶高温合金γ/γ′相界面错配位错网络的特征.通过对界面位错的形成、位错的反应、位错网络的演化等现象的分析发现,在温度场影响下,位错网络将由弛豫初期的十四面体演化成最终的正六面体. 关键词： 镍基单晶高温合金 相界面错配位错 位错网络演化 分子动力学     

Anisotropic elastic properties and ideal uniaxial compressive strength of TiB_2 from first principles calculations

The structural, anisotropic elastic properties and the ideal compressive and tensile strengths of titanium diboride(TiB_2) were investigated using first-principles calculations based on density functional theory. The stress–strain relationships of TiB_2 under 1010, 1210, and 0001 compressive loads were calculated. Our results showed that the ideal uniaxial compressive strengths are |σ _(1210)| = 142.96 GPa, |σ_(0001)| = 188.75 GPa, and |σ_(1010)| = 245.33 GPa, at strains -0.16,-0.32, and-0.24, respectively. The variational trend is just the opposite to that of the ideal tensile strength withσ 1010 = 44.13 GPa, σ_(0001)= 47.03 GPa, and σ_(1210)= 56.09 GPa, at strains 0.14, 0.28, and 0.22, respectively. Furthermore, it was found that TiB_2 is much stronger under compression than in tension. The ratios of the ideal compressive to tensile strengths are 5.56, 2.55, and 4.01 for crystallographic directions 1010, 1210, and 0001, respectively. The present results are in excellent agreement with the most recent experimental data and should be helpful to the understanding of the compressive property of TiB_2.     

阻抑动力学荧光法测定氨苄青霉素

氨苄青霉素属于β-内酰胺类抗生素,是国内临床上广泛使用的广谱青霉素,其含量测定多采用紫外可见分光光度法[1-2]、高效液相色谱法[3]、电位滴定法[4]、化学发光法[5]、极谱法[6]等。但上述方法有的试剂繁多操作复杂,有的费时,灵敏度不高,线性范围较窄。美国药典(第23版)采用剩     

Effect of Re on stacking fault nucleation under shear strain in Ni by atomistic simulation

The effect of Re on stacking fault(SF) nucleation under shear strain in Ni is investigated using the climbing image nudged elastic band method with a Ni–Al–Re embedded-atom-method potential. A parameter(?Eb sf), the activation energy of SF nucleation under shear strain, is introduced to evaluate the effect of Re on SF nucleation under shear strain. Calculation results show that ?Eb sfdecreases with Re addition, which means that SF nucleation under shear strain in Ni may be enhanced by Re. The atomic structure observation shows that the decrease of ?Eb sfmay be due to the expansion of local structure around the Re atom when SF goes through the Re atom.     

嵌入原子法研究Ni3Al中点缺陷以及Re择优占位和集团化

基于纯金属元素Ni,Al和Re的基本物理性质,建立了一个Ni-Al-Re三元体系的分析型嵌入原子多体势.结合分子动力学计算了Ni3Al的平衡晶格常数、弹性模量、结合能、空位形成能以及反位置缺陷形成能,并分析了Ni3Al中点缺陷的存在形式.计算结果表明, 当成分偏离理想化学配比时出现反位置缺陷.同时研究了Re在Ni3Al中的择优占位以及Re在Ni3Al和Ni中的集团化行为.计算结果表明,Re在Ni3Al中优先置换Al的位置,且发现当Re原子团的尺寸接近于11。A时,Re原子团的长大趋势变弱.计算结果与实验以及其他的理论计算结果相符合.