Replication and surface properties of micro injection molded PLA/MWCNT nanocomposites

Multi-walled carbon nanotube (MWCNT) reinforced polylactide (PLA) nanocomposites were injected molded into a mold with micro needle patterns. In order to alleviate the hesitation effect caused by an increased melt viscositgy of PLA/CNT nanocomposites, the effects of the injection speed and holding pressure on the replication property were investigated. The effects of MWCNTs on the crystallization, thermal behavior, replication properties, replication and surface properties of micro injection molded PLA/CNT nanocomposites were investigated. An analysis of crystallinity and thermal behavior indicated that the MWCNTs promoted the unique α’ to α crystal transition of PLA, leading to an enhancement of surface modulus and hardness, as measured using a nanoindentation technique. The specific interaction between PLA and MWCNTs was characterized using an equilibrium melting point depression technique. Furthermore, the MWCNTs increased the activation energy for thermal degradation of PLA due to the physical barrier effect. The improved replication quality of the microfeatures in the PLA/MWCNT nanocomposites has been achieved by elevating injection speed and holding pressure, which enhances the polymer filling ability within the micro cavity. A replication ratio greater than 96% for the micro injection molded PLA/CNT nanocomposites were achieved at holding pressure of 100 MPa and injection speed of 120 mm/s. This study shows that processing conditions significantly influence the replication and surface properties of micro injection molded PLA/CNT nanocomposites.     

两个二亚胺-铜(Ⅰ)-膦配合物的合成、结构和太赫兹时域光谱（英文）

本文报道了2个新的Cu(Ⅰ)配合物:[Cu(PPh3)2(dppz)]I(1)(PPh3=三苯基膦,dppz=二吡啶并[3,2-a∶2′,3′-c]吩嗪)和[Cu2(dppm)2(dppz)2]Cl2(2)(dppm=双(二苯基膦)甲烷)的合成,并通过X射线单晶衍射、元素分析、核磁共振氢(膦)谱、荧光光谱和太赫兹时域光谱对其进行了分析和表征。分析结果显示配合物1是一个单核配合物,中心Cu(Ⅰ)离子与2个含膦配体(PPh3)和1个含氮配体(dppz)进行配位,形成了一个扭曲的四面体结构。与1不同的是,配合物2是由CuCl,dppm和dppz以1∶1∶1的比例混配得到的双核配合物。其中,双膦配体dppm作为桥联配体,连接了2个Cu(Ⅰ)离子。荧光光谱表明所有的发射峰均源于金属到配体的电荷转移跃迁(MLCT)。同时,使用太赫兹时域光谱技术表征了2种配合物以及相应的配体。     

Electrochemical synthesis of selenocyanated imidazo[1,5-a]quinolines under metal catalyst-and chemical oxidant-free conditions

Reported herein is the first example of electrochemical selenocyanation of imidazo[1,5-a]quinolines with KSeCN under metal catalyst-and chemical oxidant-free conditions.This sustainable strategy shows a broad scope and great compatibility with functional groups,and affords synthetically and biologically important selenocyanated imidazo[1,5-a]quinolines in good to excellent yields with cheap graphite and Ni plates as the electrodes.The gram-scale synthesis was also successfully conducted,which might demonstrate the potential value of this electrochemical protocol.     

Molecular engineering of CxNy: Topologies,electronic structures and multidisciplinary applications

As a class of metal-free two-dimensional (2D) semiconductor materials, polymeric carbon nitrides have attracted wide attention recently due to its facile regulation of the molecular and electronic structures, availability in abundance and high stability. According to the different ratios of C and N atoms in the framework, a series of C_xN_y materials have been successfully synthesized by virtue of various precursors, which further triggers extensive investigations of broad applications ranging from sustainable photocatalytic reactions and highly sensitive optoelectronic biosensing. In view of topological structures on their electronic structures and material properties, the as-reported C_xN_y could be generally classified into two main categories with three- or six-bond-extending frameworks. Owing to the effective n→π* transition in most C_xN_y materials, the relative energy level of the lone-pair electrons on N atoms is high, which thus endows the materials with the capability of visible light absorption. Meanwhile, the different repeating units, bridging groups and defect sites of these two kinds of C_xN_y allow them to effectively drive a diverse of promising applications that require specific electronic, interfacial and geometric properties. This review paper aims to summarize the recent progress in topological structure design and the relevant electronic band structures and striking properties of C_xN_y materials. In the final part, we also discuss the existing challenges of C_xN_y and outlook the prospect possibilities.     

New Simple Method for Obtaining Integrable Hierarchies of Soliton Equations with Multicomponent Potential Functions

A new simple method for obtaining integrable hierarchies of soliton equations is proposed. First of all, a new loop algebra is constructed, whose commutation operation is clear as that in loop algebra . Second, by making use of the Tu scheme, many of integrable hierarchies with multicomponent potential functions can be produced. As a specific application of our method, a multicomponent AKNS hierarchy is obtained. Finally, an expanding loop algebra of the loop algebra is constructed. Taking advantage of above, a type of integrable coupling system of the multicomponent AKNS hierarchy is worked out.     

Influence of Bi underlayer on the magnetic properties of Fe<Subscript>x</Subscript>Pt<Subscript>100-x</Subscript> (<Emphasis Type="BoldItalic">x</Emphasis> =<Emphasis Type="Bold">40</Emphasis>∼<Emphasis Type="Bold">58</Emphasis>) films

We have studied the effect of a Bi underlayer on ordering and coercivity H_c of Fe_xPt_100-x thin films (atomic content of Fe x=40∼58). We found that the Bi underlayer enhances H_c remarkably. After annealing at 400 °C for 20 min, a Bi/Fe₄₉Pt₅₁ film can realize an H_c as high as 1.07×10³ kA/m and a ratio of the remnant M_r to the saturated magnetization M_s as high as 0.93. The ordering process of FePt film was promoted by the diffusion of Bi atoms. Moreover, the Bi underlayer broadens the range of x for high H_c from 49∼55 to 43∼55. Interestingly, with Bi underlayer, the high H_c is affected by x to a less extent. PACS 75.50.Ss; 75.50.Vv; 75.60.Ej     

北京同步辐射装置3W1B软X射线光束线偏振特性测量

应用自行研制的Mo/Si周期多层膜作为起偏器和检偏器的光学元件, 测量了北京同步辐射装置3W1B束线的偏振状态. 通过数据分析, 得到了3W1B软X射线的有关偏振参数, 在86—89eV能区经过起偏器后的偏振度超过98%, 圆偏振分量介于1%—3%之间.     

Improvement of foaming ability of egg white product by irradiation and its application

To investigate the enhancement of foaming abilities of liquid egg white (LEW) and egg white powder (EWP) by irradiation and its application for bakery product, LEW and EWP were irradiated at 0, 1, 2, and 5 kGy by Co-60 gamma ray. There was no pH change found among treatments in both LEW and EWP. The viscosity of LEW decreased significantly by irradiation (P<0.05), whereas that of EWP was not affected by irradiation. The foaming ability of LEW and EWP was significantly increased by irradiation as a dose-dependent manner (P<0.05). The volume and the height of angel cake baked with irradiated LEW were significantly higher than those of unirradiated control (P<0.05). For EWP, the volume and the height of angel cake were greater at 2 kGy only than those of control. A significant decrease in hardness, chewiness, and gumminess values and an increase in Hunter L* value were observed in the angel cakes prepared from irradiated egg white products (P<0.05). Results indicated that irradiation of egg white could offer advantages in increasing foaming ability and improving quality of final bakery products.     

基于非协调有限元方法的特征值的下界逼近

本文将文献提出的非协调元方法用于二阶椭圆特征值问题,证明了最优的误差估计.并且证明了当网格充分细时,近似特征值总是比真解小.