超支化聚合物的性能、合成及其功能化应用研究

超支化聚合物，具有多端基的“缺陷核壳”空间结构，化学反应性活泼，易于改性，与相应的线型聚合物相比，拥有特殊的性能，在多领域展现出广阔的应用前景。随着合成技术的进步，它们的应用研究，尤其是功能化的应用研究，成为多年来的研究热点。主要介绍超支化聚合物的结构、性能、合成及其功能化应用研究概况。     

Maximum bubble loads: Experimental measurement vs. analytical estimation

This paper presents an experimental technique to measure maximum bubble loads, which are then compared with geometrical model estimations. The geometrical models studied assume that a particle monolayer, having a square arrangement, covers the entire bubble surface. Comparison of the experimental and analytical results gave a fairly high statistical correlation (R² = 0.89), when a shape factor was used for particle volume estimation (λ = 0.32–0.41; [Kelly, E.G., Spottiswood, D.J. Introduction to Mineral Processing, John Wiley & Sons, 1982, p. 491]). This supports the applicability of geometrical models for maximum bubble load estimation.     

高沸石配比陶瓷纤维复合纸制备中助留剂的选择

考察了沸石复合纸板制备中助留剂对无机物留着的影响。结果表明,PDADMAC或A-PAM单元体系、PVAm/A-PAM二元助留体系的作用效果差,PDADMAC/A-PAM二元助留体系的留着效果显著,PDADMAC的相对分子质量对留着效果的影响不大,PDADMAC与A-PAM的电荷量比是决定无机物留着的主要因素,本研究的条件下,最佳正负电荷量比为3.0～5.0。     

Biomimetic synthesis of spherical nano-hydroxyapatite in the presence of polyethylene glycol

Spherical nano-hydroxyapatite (nano-HA) was synthesized successfully by a biomimetic method using Ca(NO₃)₂·4H₂O and (NH₄)₃PO₄·3H₂O as reagents in the presence of polyethylene glycol (PEG). The crystalline phase, microstructure, chemical composition, and morphology of the obtained samples were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). The results show that spherical nano-HA with diameter of 30–50 nm can be synthesized in the presence of a certain concentration (2–6%) of PEG. The crystallinity of HA powder synthesized in the presence of PEG was higher than that synthesized in the absence of PEG, but the crystallinity of HA reduced with increasing the concentration of PEG. The electrical conductivity (EC) of the solution revealed that PEG reduced the transfer rate of Ca²⁺ in the process of HA crystallization, indicating the interaction between PEG and HA. The possible mechanism of formation spherical nano-HA was discussed.     

A unified formulation of Kautz network and generalized hypercube

Hypercube and Kautz network each possess certain desirable properties. However, some of the attractive features of one network are not found in the other. A novel class of network topologies proposed in this paper has the generalized hypercube and the Kautz network as its two extremes. The proposed network inherits the topological properties of both the Kautz network and the generalized hypercube to a varying degree. This allows us to trade-off cost and performance effectively and construct networks which are most suitable for a particular purpose. In the present paper, we investigate the connectivity, wide-diameter, fault-tolerance, Hamiltonicity.     

Zr替代Ti对Ti19．5V40Mn16．2Cr9．8Ni14．5合金的影响Ⅱ：电化学性能

在对合金微观结构和储氢性能研究的基础上，详细考察了少量Zr取代Ti对Ti19．5V40Mn16．2Cr9．8Ni14．5合金电化学性能的影响。通过观察电极的充放电行为，并结合EIS及多种极化曲线的分析结果，发现少量Zr对Ti的取代能够显著提高合金电极的实际电化学容量和循环稳定性，而且还能在一定程度上改善合金的电极动力学性能。对于这些性能的改善，从合金微观结构方面进行了解释。     

聚合物材料脆韧转变判据及影响因素分析

综述了聚合物共混增韧机理包括弹性体增韧、刚性粒子增韧、弹性体与刚性粒子协同增韧等研究进展；着重介绍了临界基体层厚度、损伤竞争准数、分子链参数、临界界面黏结条件、临界特征长度等几种源于单一粒子填充的脆韧转变判据，并分析其在复合粒子填充改性聚合物中的适用性。此外，还结合增韧机理和脆韧转变判据讨论了基体性能、分散相状态及相间界面黏结强度等因素对复合体系韧性的影响，提出寻找合适的复合分散相、适当调整复合粒子的结构比例、改善相间界面黏结以及设计最佳断裂路径仍将是今后努力的方向。     

Synthesis of chaoite-like macrotubes at low temperature and ambient pressure

Chaoite-like carbon was prepared by quenching the pyrolysate of acetylene gas at 873 K and ambient pressure. Its morphology is carbon macrotubes (CMTs) with 20–60 μm in diameter and up to 8 mm in length. Microstructure analysis revealed that sp-bonded carbon (SPBC) chains in CMTs are kinked and the crystal orientation is anisotropic along the length and circumference directions of CMTs. A SPBC belt scrolling model was proposed for explaining the formation process of CMTs.     

A comprehensive approach to evaluating watershed models for predicting river flow regimes critical to downstream ecosystem services

Selection of strategies that help reduce riverine inputs requires numerical models that accurately quantify hydrologic processes. While numerous models exist, information on how to evaluate and select the most robust models is limited. Toward this end, we developed a comprehensive approach that helps evaluate watershed models in their ability to simulate flow regimes critical to downstream ecosystem services. We demonstrated the method using the Soil and Water Assessment Tool (SWAT), the Hydrological Simulation Program–FORTRAN (HSPF) model, and Distributed Large Basin Runoff Model (DLBRM) applied to the Maumee River Basin (USA). The approach helped in identifying that each model simulated flows within acceptable ranges. However, each was limited in its ability to simulate flows triggered by extreme weather events, owing to algorithms not being optimized for such events and mismatched physiographic watershed conditions. Ultimately, we found HSPF to best predict river flow, whereas SWAT offered the most flexibility for evaluating agricultural management practices.     

IPv6 WLAN安全网关设计

IPv6强大的寻址方案和对移动性的支持,使其在WLAN中的应用成为一种趋势。WLAN为用户提供了便捷接入的同时,也带来相较于有线网络更大的安全威胁,IPv6的邻居发现协议和自动配置功能等这些特点使得WLAN的接入安全变得更为复杂。设计一个IPv6 WLAN环境下的安全网关,能够检测到网络中潜在的漏洞和威胁,通过搭建实验环境,并对未授权接入、DAD DOS攻击和重定向攻击三种安全威胁进行了仿真,实验结果证明该安全网关的有效性。