阻燃双酚A型聚碳酸酯/丙烯腈-丁二烯-苯乙烯共聚物合金研究进展

介绍了双酚A型聚碳酸酯（PC）的热分解机理及热分解产物,综述了阻燃PC/丙烯腈-丁二烯-苯乙烯共聚物（ABS）合金的研究进展,重点介绍了无卤阻燃体系包括磷系、硅系阻燃剂及复配型阻燃剂的研究进展及相关阻燃机理,并指出了阻燃PC/ABS合金将来的研究重点和发展方向。目前,PC/ABS合金的阻燃逐渐向着无卤、高效、低毒、环保的方向发展,提高阻燃剂的阻燃效率、减少添加量、降低成本和对环境的危害是今后阻燃的重要研究方向,且开发新型或复配型无卤阻燃剂已成为PC/ABS合金阻燃的必然趋势。     

(2PRR)~2+R平面并联机构的刚度与固有频率

基于两移动一转动三自由度平面并联机构构造了一种新型五自由度串并混联机器人并对其并联部分,一具有运动冗余和驱动冗余两种不同模式的平面并联机构(2PRR)~2+R进行了运动学分析。首先,建立了三自由度平面并联机构的运动学模型,基于机构的运动学模型推导得到了冗余和非冗余驱动并联机构的刚度矩阵,并且通过求取并联机构各组成构件的等效质量,得到并联机构的质量矩阵;然后,借助系统刚度矩阵和质量矩阵建立的并联机构动力学方程,求得了机构的固有频率方程;最后,通过数值仿真对冗余和非冗余驱动并联机构的刚度及固有频率进行对比分析。结果显示:冗余驱动分支对机构绕Z轴方向角刚度和系统的一阶固有频率均值影响最大,其增幅分别为88.46%和31.50%;对X轴方向的线刚度和系统的二阶固有频率均值影响最小,其增幅分别为52.34%和1.90%。因此,冗余驱动分支有助于提高并联机构的整体刚度,改善机构的动态性能。     

新型PURU+RR+S球面并联人形机器人踝关节机构动力学性能分析

提出了一种新型PURU+RR+S球面并联人形机器人踝关节机构,根据机构的几何约束关系和速度合成定理,建立包括各个构件位姿、速度的机构运动学模型。在此基础上,考虑各构件惯性力的影响,基于虚功原理和拉格朗日方程,建立了机构动力学模型。通过实验测量,得到一组人体踝关节的运动学数据,利用傅里叶公式进行拟合,得到人体踝关节的位姿函数。将此位姿函数分别作为理论模型、踝关节虚拟样机的输出,得到踝关节机构输入的数值解、仿真数据,验证了运动学和动力学模型的正确性。研究结果为该人形机器人踝关节机构在工程中的结构设计与应用提供了动力学理论基础和依据。     

硫酸盐有机废水厌氧处理颗粒污泥研究进展

厌氧工艺是硫酸盐有机废水处理中最具竞争力的技术,厌氧颗粒污泥则是其核心,开展该类废水厌氧处理颗粒污泥特性的研究,对提高其厌氧处理效率具有重要意义。本文综述了硫酸盐有机废水厌氧处理颗粒污泥近年来的国内外研究进展,主要包括颗粒污泥的理化特性（形态及粒径、孔隙、通道及沉降速度、胞外沉积物等）及颗粒污泥的生物学特性（生物活性、微生物形态、组成及分布）,并分析了此方面研究工作存在的问题,认为硫酸盐有机废水厌氧处理颗粒污泥活性抑制机理的研究以及从本质上解除这种抑制措施的提出,将是今后需要重点关注的研究内容。     

厌氧颗粒污泥处理含铅废水的机理探讨

本文对厌氧颗粒污泥处理含铅废水的机理进行了实验研究,分析了颗粒污泥处理含铅废水的影响因素,并对其机理进行了探讨,结果表明硫酸盐的投加一定程度上促进了SRB的生长并创造了利于硫化铅沉淀的环境,为厌氧颗粒污泥处理含铅废水提供了有效途径.     

Facile synthesis of different morphologies of Te-doped ZnO nanostructures

Te-doped ZnO nanostructures were synthesized by an annealing (vapor–solid) process under ambient conditions, and characterized in terms of their morphological, structural, compositional and optical properties. The structural and morphological characterizations revealed that the synthesized nanostructures were well-defined multipods, needles and spherical particles, and possessed well-crystalline ZnO wurtzite hexagonal phase. Also, in the X-ray diffraction studies, the presence of a shift in the peak positions towards a lower angle, and a decrease in the intensity, with an increase in the Te concentration, as compared to the undoped ZnO, were observed. The chemical composition confirmed the presence of Te, in the case of multipod and needle morphologies. The effect of doping on the crystalline quality and optical properties was also investigated, by using photoluminescence (PL) and Raman spectrometers. The Raman results demonstrated that the doped ZnO nanostructures had a lower crystalline quality than the undoped ZnO. Moreover, the PL results showed a decrease in the band gap for the doped ZnO nanostructures, in comparison to the undoped ZnO. A possible growth mechanism was also proposed.     

Long Non-Coding RNAs: Critical Players in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a complex disease with multiple underlying pathogenic mechanisms caused by a variety of etiologic factors. Emerging evidence showed that long non-coding RNAs (lncRNAs), with size larger than 200 nucleotides (nt), play important roles in various types of cancer development and progression. In recent years, some dysregulated lncRNAs in HCC have been revealed and roles for several of them in HCC have been characterized. All these findings point to the potential of lncRNAs as prospective novel therapeutic targets in HCC. In this review, we summarize known dysregulated lncRNAs in HCC, and review potential biological roles and underlying molecular mechanisms of lncRNAs in HCC. Additionally, we discussed prospects of lncRNAs as potential biomarker and therapeutic target for HCC. In conclusion, this paper will help us gain better understanding of molecular mechanisms by which lncRNAs perform their function in HCC and also provide general strategies and directions for future research.     

Synthesis of parallel squared nanosheet-assembled Bi2WO6 microstructures under alkalescent hydrothermal treatment

The hierarchical Bi₂WO₆ microstructures, which were two-dimensionally assembled by parallel squared nanosheets, were synthesized under alkalescent hydrothermal treatment. The crystalline phase, morphology, size, lattice plane and crystalline structure of the products were characterized by X-ray diffraction, scanning/transmission electron microscopy and selected area electron diffraction. The formation of parallel squared nanosheet-assembled hierarchical Bi₂WO₆ microstructures was elucidated by the oriented attachment growth mechanism based on our experimental results. The aqueous ammonia, which was employed as the alkalescent environment, had a critical effect on the formation of such hierarchical Bi₂WO₆ microstructures with a large proportion of {001} facets. The parallel squared nanosheet-assembled hierarchical Bi₂WO₆ microstructures obtained at the hydrothermal temperature of 120 °C showed high photocatalytic activity under visible-light irradiation.     

定模带斜推机构的手机下盖注射模设计

以手机下盖为研究对象,分析了该产品的工艺特点,提出了完善的注射模设计方案.针对制件内外形结构复杂,有侧孔的情况,采用一模一腔,双分型面、潜伏浇口进料的模具结构.该模具设计了一种斜推内侧抽芯机构,以替代弹簧内侧抽芯结构.解决了其寿命低、不稳定的问题,可为类似制品的模具设计提供参考.