Diffusion-induced Spatio-temporal Oscillations in an Epidemic Model with Two Delays

We investigate a diffusive, stage-structured epidemic model with the maturation delay and freelymoving delay. Choosing delays and diffusive rates as bifurcation parameters, the only possible way to destabilize the endemic equilibrium is through Hopf bifurcation. The normal forms of Hopf bifurcations on the center manifold are calculated, and explicit formulae determining the criticality of bifurcations are derived. There are two different kinds of stable oscillations near the first bifurcation: ...     

锗钨酸分子间化合物的合成和结构研究

以锗钨酸和4-甲基吡啶为原料合成了分子间化合物H₄GeW₁₂O₄₀·5C₆H₇N·CH₃CN。单晶X-射线分析表明，属正交晶系，空间群P2₁2₁2₁, 晶胞参数a=13.533(5),b=20.835(5), c=21.859(7)?，V=6164(3)?³。Dc=3.650 Mg/m³, Z=4。对3934个可观察到的衍射点进行全矩阵最小二乘法修正后，可靠性因子R=0.0534。     

流动注射分光光度法测定水体总磷

提出了一种单通道紫外消解流动注射比色分析法，能快速测定水样中总磷。实验采用了微量恒流混合泵、新型的细长型高灵敏度流通池及紫外消解器、液流分配阀、恒流瓶等FIA装置，并使用工业编程控制器和智能触摸屏进行控制和计算，使操作更为方便。此法分析时间短，测量范围宽，精度高，适合于各种水体的测定。     

Self-repairing polymers: poly(dioxaborolane)s containing trigonal planar boron

The molecular weight of poly(dioxaborolane)s can be controlled during the polymerization reaction or through post-polymerization processing in such a manner that hydrolytic damage to these materials may be repaired, thereby regenerating the polymer.     

尼龙—6／丙烯酸接枝膜的结构与性能

应用ＩＲ确定了尼龙－６与丙烯酸接枝反应的接枝点位于尼龙大分子酰胺键的Ｎ原子上，用Ｘ射线衍射研究了接枝膜的结晶状况，探讨了接枝率对接枝膜的电阻、离子交换容量、强度等性能的影响．     

反相离子对高效液相色谱法测定硫酸软骨素

以四甲基氯化铵作为离子对试剂，采用乙腈-2.28mmol/L四甲基氯化铵水溶液（5:95)作为流动相，选用C18色谱柱分离硫酸软骨素和杂质，建立了测定硫酸软骨素含量的反相离子对高效液相色谱方法。该方法的线性范围为0.4-8.0μg，回收率为98.8%-100.3%，相对标准偏差为0.17%-0.53%。该方法的精密度和准确度较高。