THE EXTINCTION OF A NON-AUTONOMOUS ALLELOPATHIC PHYTOPLANKTON MODEL WITH FEEDBACK CONTROLS

A non-autonomous allelopathic phytoplankton model with feedback controls is considered in this paper. By constructing some suitable Lyapunov type extinction functions, some sufficient conditions for the extinction of the system are obtained. For the autonomous case, by constructing a suitable Lyapunov function, we show that one species is extinct and the rest species is globally attractive. Our results supplement some known results.     

Dicarboxylic imide‐substituted poly(p‐phenylene vinylenes) with high electron affinity

Synthesis of n‐type organic semiconductors with high electron mobilities, good environmental stability, and good processability is an urgent task in current organic electronics. This is because most of π‐conjugated materials are p‐type and prefer to transport positive hole carriers. In this article, a series of new dicarboxylic imide‐substituted poly(p‐phenylene vinylenes) (DI‐PPVs) were first synthesized. They exhibited a high electron affinity of 3.60 eV and thus are able to transport electrons. The polymers showed tunable solubility in common organic solvents and high chemical and thermal stability. They remain rigidity of the PPV backbone, and strong interchain π‐stacking was observed in thin films by X‐ray diffraction measurement. All these suggested that these polymers could serve as good candidates as n‐type semiconductors in organic electronic devices such as n‐channel field‐effect transistors and all polymer‐based solar cells. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 186–194, 2010     

在两层不同爆速炸药滑移爆轰作用下飞板运动的数值计算研究

本文研究用低爆速炸药复盖高爆速炸药在定滑移爆轰作用下飞板运动的计算方法,并对惯性复盖与炸药复盖的结果作出相互比较。     

双金属爆炸焊接上限

本文根据热传导理论给出了爆炸焊接时双金属结合区附近的温度场解析解。并利用该解初步研究了双金属的爆炸焊接上限。     

Semi-Preparative Scale Separation of Emodin from Plant Extract by Using Molecularly Imprinted Polymer as Stationary Phase

In this work, a core–shell molecularly imprinted polymer (MIP) was synthesized through sol–gel coating procedure by using silica beads, emodin, 3-aminopropyltriethoxysilane, tetraethoxysilane and tetrahydrofuran as supporting matrix, template, functional monomer, cross-linker and solvent, respectively. The selective recognition property for emodin and its analogues (physcion and aloe emodin) of the resultant MIP was evaluated in a chromatographic column for high-performance liquid chromatography (HPLC). The retention time and imprinted factor of MIP column for emodin, physcion and aloe emodin were 5.11, 0.63, 0.69 min and 4.69, 0.75, 1.38, respectively. It showed that the MIP beads had a good binding ability for emodin. Finally, one-step separation of emodin from alcohol extract of Rheum palmatum L. at semi-preparative scale was achieved and 380 mg of emodin was collected in 5 days. The product was characterized by mass spectrometry and HPLC and its purity was 95 %.     

奇异Hamilton-Jacobi-Bellman方程粘性解的存在唯一性

研究系数在边界点有奇性的一类Hamilt on- Jacobi- Bellman (HJB)方程的粘性解的存在唯一性问题及解的渐近估计,这类问题包括波动系数振荡或爆破的情况.奇异HJB方程在随机最优控制和金融数学等许多领域都有重要的应用,包括金融数学中的随机利率模型.应用粘性上下解理论建立了一类奇异HJB方程的比较原理,给出了粘性解存在唯一性的条件.     

Dynamical behavior of a stochastic Nicholson’s blowflies model with distributed delay and degenerate diffusion

Nonlinear Dynamics - The mathematical model with time delay is often more practical because it is subject to current and past state. What remains unclear are the details, such as how time delay and...     

受乳糖启动子控制的基因表达过程的优化

借助于ＳＤＳ－聚丙烯酰胺凝胶电泳分析方法，对乳糖诱导的由乳糖启动子控制的大肠杆菌ＲＮＡ聚合酶σ７０因子基因表达过程进行了优化研究．结果表明，含此融合基因的大肠杆菌菌株ＢＬ２１（ＤＥ３）ｐＧＥＭＤ的生长量达到ＯＤ６００ｎｍ＝１．０时，用终浓度为０．０８％的乳糖进行连续５ｈ的诱导，可使大肠杆菌ＲＮＡ聚合酶σ７０因子基因的表达量达到最大，并达到ＩＰＴＧ同样的诱导效果．流加低浓度的乳糖溶液能增加σ７０因子的合成量，但是促进作用不很显著．     

非晶合金条带的爆炸焊接

 报道了利用爆炸焊接技术对铁基、铁镍基非晶合金条带（厚度约25 μm）进行单层和多层爆炸焊接的结果。金相分析结果表明，条带间相互结合良好；X光衍射结果说明，焊接后的条带仍保持非晶态，即使采用表面已有部分晶化德条带进行焊接，焊接后仍转化为非晶态。这说明在焊接过程中条带表面已发生熔化，且冷却速度也可达10⁶ K/s量级。     

Eigenvalues of scaling operators and a characterization of -splines

A finitely supported sequence that sums to defines a scaling operator on functions a transition operator on sequences and a unique compactly supported scaling function that satisfies normalized with It is shown that the eigenvalues of on the space of compactly supported square-integrable functions are a subset of the nonzero eigenvalues of the transition operator on the space of finitely supported sequences, and that the two sets of eigenvalues are equal if and only if the corresponding scaling function is a uniform -spline.