In this study, polyvinylidene fluoride/organic rectorite (PVDF/OREC) organic-inorganic nanocomposite membrane was prepared by phase conversion method. TEM and X-ray diffraction (XRD) results demonstrate the successful fabrication of nanocomposite ultrafiltration membranes. When the OREC is less than 3 wt%, the nanosheets are mainly stripped and dispersed in the polymer matrix, with different numbers of intercalations. When the impurity content is 5%, the intercalation distribution dominates. When the impurity content increases to 7% and above, it becomes increasingly difficult for PVDF chain segments to enter the OREC interlayer and the OREC particles are dominated by simple blends on the order of micrometers in the polymer matrix. The inclusion of inorganic fillings significantly improved the mechanical properties of the membrane. The yield strength and tensile modulus of the membrane were increased by 53.7% and 574.9%, respectively, with an inorganic filler content of 5 wt%, while the elongation at the break was slightly decreased to 16.2%. This suggests a strong interaction between the OREC nanosheets and the polymer matrix. XRD and FTIR analyses indicate that OREC particles are effective heterogeneous nucleating agents that favor the formation of beta-phase crystals in the film. SEM surface and cross-section results show that when joining can significantly reduce the average pore size of the membrane surface, large holes tend to reduce the number of holes in the skin layer distribution more uniformly. The AFM results show that the addition of OREC can significantly alter the surface roughness of ultrafiltered membranes, and that the changes in surface roughness and surface pore morphology of membranes with different clay contents are closely related to the distribution of nanoscale silicate sheets in the PVDF matrix.HighlightsPrepared PVDF/OREC nanocomposite membranes via a phase-inversion process.OREC acted as a potent nucleation agent, favoring beta crystal formation.OREC resulted in smaller pore sizes and fewer large pores in the skin layer.The hydrophilicity of PVDF membranes was reformative by filling OREC.OREC led to increased water flux and BSA rejection due to pores and hydrophilicity. The structural sketch of OREC modified PVDF membranes.image

Crystallization, a characteristic property of natural rubber, has great effect on the storage and application in industrial. Based on different milling times, natural rubber samples were prepared. Moreover, structure of natural rubber with different milling times, i.e. molecular weight, group transform, cross-link density (entanglement), and rheology were analyzed by gel permeation chromatograph (GPC), Fourier transform infrared spectrum (FTIR), and rubber processing analyzer (RPA), respectively. Furthermore, temperature induced crystallization parameters were mounted on differential scanning calorimeter (DSC). The results demonstrated that temperature induced crystallization rate decreased with the increment of milling times, whereas the average molecular weight measured by GPC decreased with milling times increasing. However, the average cross-link molecular weight increased which was compatible to the temperature induced crystallization rate. It was concluded that temperature induced crystallization rate was related to the average cross-link molecular weight, but not average molecular weight.

A new solver is developed to numerically simulate the melting phase change with natural convection. This solver was implemented on a single Nvidia GPU based on the CUDA technology in order to simulate the melting phase change in a 2D rectangular enclosure. The Rayleigh number is of the order of magnitude of 10 8 and Prandlt is 50. The hybrid thermal lattice Boltzmann method (HTLBM) is employed to simulate the natural convection in the liquid phase, and the enthalpy formulation is used to simulate the phase change aspect. The model is validated by experimental data and published analytic results. The simulation results manifest a strong convection in the melted phase and a different flow pattern from the reference results with low Rayleigh number. In addition, the computational performance is estimated for single precision arithmetic, and this solver yields 703.31MLUPS and 61.89GB/s device to device data throughput on a Nvidia Tesla C2050 GPU.

The testing of a doubled-sided multi-strip silicon detector manufactured by Institute of Modern Physics of CAS and Peking University were introduced.The electrical characteristics and energy resolution,two-dimensional spectrum,crosstalk were presented.The reverse leak current of each strip is smaller than 10 nA under bias voltage of 25 V.The energy resolution of strips on the front side is about 1.5%,but a little worse for the backside strips,about 3%.The level of crosstalk is about 6% for the front side,1% for the backside.Same tests were carried out on the commercial Micron BB1 detector and a comparison was presented.

在固定床反应器上进行了自制多孔白云石颗粒催化裂解乙酸、苯等焦油模型化合物的动力学实验研究,考察了反应温度（873～1123K）、接触时间（0.3～2.0s）等反应条件对乙酸、苯转化率的影响。实验结果表明:乙酸、苯转化率均随反应温度与接触时间的增加而上升,当反应温度为1123K、停留时间为2.0s时,乙酸、苯的最大转化率分别为99.8%和18.7%;通过对乙酸与苯的催化裂解动力学分析,得出乙酸、苯的反应速率常数变化范围分别为0.41～3.64s -1 和0.00718～0.11300s -1 ,活化能分别为71.4kJ·mol -1 和94.5kJ·mol -1 。经检验,模型计算与实验结果能较好吻合。