Highly efficient toughening effect of ultrafine full-vulcanized powdered rubber on poly(lactic acid)(PLA)

A unique ultrafine full-vulcanized powdered ethyl acrylate rubber (EA-UFPR) was used as the toughening modifier for poly (lactic acid) (PLA). Largely improved tensile toughness was successfully achieved with the incorporation of only 1 wt% EA-UFPR, while the tensile strength and modulus of the blends were almost the same as pure PLA. The highly efficient toughening of PLA by UFPR is mainly ascribed to the strong interfacial interaction between PLA and UFPR and good dispersion of UFPR particles in PLA matrix. Our work provides an effective toughening method to largely improve the mechanical properties of PLA without sacrificing its stiffness, which is very important for the wide application of PLA materials.     

One-step synthesis ofα,β-unsaturated arylsulfones by a novel multicomponent reaction of aromatic aldehydes,chloroacetonitrile, benzenesulfinic acid sodium salt

A new and green method for the synthesis of α,β-unsaturated arylsulfones had been achieved through the condensation of aromatic aldehydes,chloroacetonitrile,benzenesulfinic acid sodium salt in the presence of l-butyl-3-methyl imidazolium hydroxide([bmim]OH) in EtOH under reflux.The ionic liquid was recovered and recycled for subsequent reactions.The advantages of this protocol were non-toxic,easy work-up and good yields.     

Why calcium inhibits magnesium-dependent enzyme phosphoserine phosphatase? A theoretical study

Mechanisms for the formation of the Schiff base from acetaldehyde and butylamine, glycine and phosphatidylethanolamine based on Dmol3/DFT calculations were realized. For the case of phosphatidylethanolamine, calculations were done under periodic boundary conditions, in an amine-phospholipid monolayer model with two molecules of phosphatidylethanolamine by cell. All models contained explicit aqueous solvent. In the three cases, a neutral amino group is used to model the nucleophilic attack on the carbonyl group of acetaldehyde, and water molecules form hydrogen bond networks. These networks were involved in the reactions by performing as proton-transfer carriers, important in some steps of reactions, and stabilizing reaction intermediates. In all the studied reactions, they take place in two steps, namely: (1) formation of a carbinolamine and (2) its dehydration to the Schiff base, being the dehydration the rate-determining step of the process, consistent with available experimental evidence for similar reactions. The main difference between the studied reactions is found in the value for relative free energy for the intermediates and transition states in the second step; these values are lower in the cases of glycine and phosphatidylethanolamine in comparison with butylamine, due the influence of their molecular environments. Based on the results, the aminophospholipid surface environment and carboxylic group of glycine may boost Schiff base formation via a neighboring catalyst effect.     

超声雾化法制取金属粉末方法研究

本文介绍了利用超声振动能量制取超细金属粉末的超声雾化方法，提出了超声制粉雾化室，等离子枪，阴极、阳极喷咀及换能器振动系统的最佳尺寸和工作参数，给出了实验结果及制得的粉末显微结构照片．实验结果表明，用本文所述方法制得的金属粉末组成为：－80目粉占84呢，－120目粉占63．7啪，而用PREP方法制得的粉末分别占19．5％和11．7％，由此看来，用本方法制取超细金属粉，在粒度组成方面优于PREP方法．文中还对粉末冷却速度做了估算，得到了粉末平均冷却速度大于1×10_5k/5     

集值严格集-压缩映象的一致极限的不动点指数及其应用

在本文中,我们研究了一类集值严格集-压缩映象的一致极限映象.建立了这类一致极限映象的不动点指数理论,证明了某些正不动点定理.我们的定理推广了Fitzpatrick和Petryshyn的某些最近结果.     

波动方程反演问题的一种新的逼近方法

本文给出了一种求解波动方程反演问题的“多目标函数法”.这种方法简单、有效,并具有明确的物理意义.对于三维问题的程序化它有很强的优越性.     

基于改进U-Net的量子点STM图像分割

为提升量子点图像分割精度,降低特征识别误差,提出一种基于改进U-Net的量子点图像分割方法.首先,在预处理阶段,设计了以色彩通道为权值的灰度化算法,以提升后续分割效果.其次,在STM图像分割部分,在原始U-Net结构上引入中间过渡层以均衡网络各层特征.而后,建立数据集,并通过实验对比不同分割算法的精确度、召回率、F-measure.最后,将分割算法应用于量子点的特征识别,并测试了不同分割方式对应用的影响.实验结果显示,改进灰度化方法保留细节信息丰富,明显提升了量子点分割精度;改进U-Net的平均精确率、召回率、F-measure相较原始网络分别提升了13.83%、2.16%、8.13%.同时,实验数据表明由于分割精度的提升,量子点数量、纵横比等特征参数的识别更加精确.     

The isometric extension problem in the unit spheres of l<Superscript>p</Superscript>(Г) (<Emphasis Type="Italic">p</Emphasis> >1) type spaces

In this paper, we first derive the representation theorem of onto isometric mappings in the unit spheres of l ^p (Г) (@#@(p >) 1,p ≠ 2 type spaces, and then we conclude that such mappings can be extended to the whole space as real linear isometries by using the previous result of the author.