含铜超低碳钢CCT曲线及组织

采用Formastor-F热模拟试验机测定了一种含铜超低碳钢900℃未变形奥氏体0.2～100℃/s冷速下连续冷却转变曲线,观察分析不同冷速下的相变组织,并测定对应的维氏硬度。结果表明,不同冷速下,这种超低碳钢奥氏体稳定转变成贝氏体铁素体组织,冷却速度对实际晶粒度无显著影响,冷速在3℃/s以下,组织主要为准多边形贝氏体铁素体,且在基体上析出细小ε-Cu颗粒;冷速在5℃/s以上,组织主要为贝氏体型铁素体,硬度不发生显著变化。     

深水超声波换能器设计

利用回声信号探测无声目标的原理,测量信号往返所需时间与在水中超声波声速的乘积,就可以确定目标所处的位置.根据该原理来探测海底微地形的高程数据,为此对适合于深海环境下工作的超声波换能器参数进行了理论分析与设计计算,该参数将为海底微地形探测系统提供技术依据.     

H20型全电伺服数控转塔冲床噪声分析及降噪方案

对H20型全电伺服数控转塔冲床作了介绍,对伺服转塔冲床的冲压噪声进行测量、分析,并提出了降噪解决方案。     

DD6单晶带气膜孔平板试件高周疲劳性能研究

利用电液束、激光、电火花三种不同制孔工艺制备了DD6镍基单晶高温合金气膜孔平板试验件,在980℃下对试件的高周疲劳性能进行了测试,并对疲劳极限与断口形貌进行了分析比较.结果表明:不同制孔工艺对试件的高周疲劳性能影响显著,电液束制孔工艺的疲劳极限较高速电火花制孔、毫秒激光制孔工艺提升约5.3％和7.1％.不同制孔工艺的试...     

椰壳粉/PVC复合材料的结构及动态力学性能研究

将改性椰壳粉填充到聚氯乙烯(PVC)中制得椰壳粉/PVC复合材料,用SEM、DMA对复合材料的结构和动态力学性能进行了研究。结果表明:改性后的椰壳粉与基体PVC的界面黏结强度提高;用2.0%硅烷偶联剂KH-550及15%HDPE-g-(GMA-co-St)改性后,复合材料具有较好的动态力学性能。     

Supramolecular columnar nanostructures from self‐organization of coil–rod–coil molecules incorporating an anthracene unit

We report the synthesis and self‐assembly behavior of coil–rod–coil molecules. These molecules each consist of two biphenyl groups and an anthracene unit connected with ethynyl bonds at the 1,8‐position of anthracene as a rod segment, with methoxy or octyl groups at the 10‐position of anthracene, and poly(ethylene oxide) with degrees of polymerization of 12 and 17 linked to the biphenyls as coil segments. Structural investigation of these molecules by means of differential scanning calorimetry, polarized optical microscopy and X‐ray diffraction in the bulk state reveals that these molecules self‐assemble into lamellar structures in the solid state, while, in the liquid‐crystalline phase, they self‐organize into various columnar assemblies depending on the volume fraction of coil segments. Copyright © 2011 Society of Chemical Industry     

烟道气脱硫技术进展

本文对低浓度SO2脱除方法进行了分类,综述了各种方法的脱硫机理、工艺条件和脱硫效率.     

Modified thiourea used as the ligand for the synthesis of novel coordination polymers: Based on its significant conformational behavior and H-bonding preference

Modified thiourea was used as the ligand for the synthesis of three novel coordination complexes, basing on its increased H-bond donor ability of the NH group and decreased H-bond acceptor ability of the C = S bond. Complex 1 is the first 3D network with 1D rod SBU and 2D surface SBU based on the long biscarboxylate ligand; Complex 2 has a 2D layer constructed by 1D chains via H-bonds, which shows a “plywood-like array” with a new AABB type; Complex 3 is a 3-fold interpenetrating 5-connected net with the rare 4⁶6⁴ topology.     

Porous Silicon Carbide Ceramics Produced by a Carbon Foam Derived from Mixtures of Mesophase Pitch and Si Particles

Carbon foam templates were prepared from a mixture of mesophase pitch (MP) and Si particles, followed by foaming and carbonization. Subsequent molten Si infiltrated into the carbon foam at 1500°C for 4 h in an inert atmosphere resulted in the formation of porous SiC ceramics. Micrographs were investigated by a scanning electron microscope (SEM), and phase identification of porous SiC ceramics was performed by X-ray diffraction (XRD). The flexural strength and bulk density of porous SiC ceramics were also measured and calculated. The results revealed that the flexural strength of porous SiC ceramics increases with increasing Si content and decreasing porosity. The addition of Si in MP results in an increased densification of porous SiC struts. With 50 wt% Si, porous SiC ceramics with a high flexural strength of 23.9 MPa and a porosity of 55% were obtained.     

Preparation and Characterization of Cationic PLA-PEG Nanoparticles for Delivery of Plasmid DNA

The purpose of the present work was to formulate and evaluate cationic poly(lactic acid)-poly(ethylene glycol) (PLA-PEG) nanoparticles as novel non-viral gene delivery nano-device. Cationic PLA-PEG nanoparticles were prepared by nanoprecipitation method. The gene loaded nanoparticles were obtained by incubating the report gene pEGFP with cationic PLA-PEG nanoparticles. The physicochemical properties (e.g., morphology, particle size, surface charge, DNA binding efficiency) and biological properties (e.g., integrity of the released DNA, protection from nuclease degradation, plasma stability, in vitro cytotoxicity, and in vitro transfection ability in Hela cells) of the gene loaded PLA-PEG nanoparticles were evaluated, respectively. The obtained cationic PLA-PEG nanoparticles and gene loaded nanoparticles were both spherical in shape with average particle size of 89.7 and 128.9 nm, polydispersity index of 0.185 and 0.161, zeta potentials of +28.9 and +16.8 mV, respectively. The obtained cationic PLA-PEG nanoparticles with high binding efficiency (>95%) could protect the loaded DNA from the degradation by nuclease and plasma. The nanoparticles displayed sustained-release properties in vitro and the released DNA maintained its structural and functional integrity. It also showed lower cytotoxicity than Lipofectamine 2000 and could successfully transfect gene into Hela cells even in presence of serum. It could be concluded that the established gene loaded cationic PLA-PEG nanoparticles with excellent properties were promising non-viral nano-device, which had potential to make cancer gene therapy achievable.