3D Nanocomposite Hydrogel Scaffolds Fabricated by Rapid Prototyping for Bone Tissue Engineering

Colloidal gels made of oppositely charged nanoparticles are a novel class of hydrogels and can exhibit pseudoplastic behavior which will enable them to mold easily into specific shapes. These moldable gels can be used as building blocks to self-assemble into integral scaffolds from bottom to up through electrostatic forces. However, they are too weak to maintain scaffold morphology just depending on interparticle interactions such as Van der Waals attraction and electrostatic forces especially for bone tissue engineering. In this study, oppositely charged gelatin nanoparticles were firstly prepared by two-step desolvation method, followed by the mixture with water to form colloid gels. To solve the problem of weak mechanical performance of colloid gels, gelatin macromolecules were introduced into the prepared gels to form blend gels. The blend gels can be easily processed into three-dimensional （3D） porous scaffolds via motor assisted microsyringe （MAM） system, a nozzle-based rapid prototyping technology, under mild conditions. After fabrication the scaffolds were erosslinked by glutaraldehyde （ GA, 25 % solution in water by weight）, then the crosslinked gelatin macromolecules network could form to improve the mechanical properties of colloid gels. The average particle size and zeta potential of gdatin nanoparticles were measured by Nano- ZS instrument. The morphology and microstructures of scaffolds were characterized by macroscopic images. The mechanical properties of the scaffolds were studied by a universal material testing machine.     

铜离子掺杂钒基配位聚合物的制备及其超级电容器性能

通过两步微波和离子交换的方法得到一种直径约为 1.5 μm 的微球形貌铜离子掺杂钒基配位聚合物 (V-Cu-HHTP). 聚合物中部分取代的 Cu$^{2+}$提高了配位聚合物的导电性和结构稳定性, 并提供 V、Cu 的协同效应, 在用于超级电容器电极材料时表现出良好的电化学性能. 在 1 A$\cdot$g$^{-1}$ 的电流密度下, V-Cu-HHTP 表现出 287 F$\cdot$g$^{-1}$ 的比容量, 在 10 A$\cdot$g$^{-1}$ 的大电流密度下循环 3 000 圈后, V-Cu-HHTP 的电容保持率仍有 98.6%, 比相同测试条件下未掺杂的 V-HHTP 电极表现优异 (比容量为 227 F$\cdot$g$^{-1}$, 电容保持率为 94.2%). 选取 V-Cu-HHTP 作为正极, 活性炭 (activated carbon, AC) 作为负极, 组装非对称超级电容器 V-Cu-HHTP//AC, 电压窗口达到 1.6 V. V-Cu-HHTP//AC 在功率密度为 795.0 W$\cdot$Kg$^{-1}$ 时, 最大能量密度为44.1 Wh$\cdot$Kg$^{-1}$, 优于许多钒基超级电容器. 优异的电化学性能归因于: 双金属配位聚合物的设计为体系提供了优异的协同效应, 提高了结构稳定性; Cu 离子掺杂提高了导电性; V-Cu-HHTP 的多孔特征为体系暴露更多活性位点, 提供优异的双电层电容特性.     

反复荷载作用下受弯构件有限元非线性分析

本文用有限元线性分析方法，研究钢筋混凝土受弯构件在反复荷载作用下的受力性能，研究混凝土材料的非线性性能，将混凝土分成８种单元，并考虑了混凝土的裂面效应，采用ＦＯＲＴＲＡＮ语言编制计算程序，对悬臂梁作全过程分析，计算得出滞回曲线，裂缝发展等，与试验数据吻合较好。     

韶关历代寺院兴衰原因初探——以南华禅寺兴衰沿革为例

历史上,韶关地区是佛教尤其是禅宗弘法和传播的重要策源地与据点,境内历代寺院遍布.在这为数众多的寺院中,南华禅寺、东平山正觉寺、云门寺以及月华寺、大梵寺、灵树寺、双峰寺、别传寺等,是禅宗的重要道场,在禅宗发展史上占有举足轻重的地位.南禅祖庭南华禅寺的兴衰沿革历史,充分说明了寺院兴衰“全维系于嗣法”,得人则兴,失人则废的道理.     

聚苯乙烯-甲基丙烯酸模板与SiO2空心微球可控性制备

利用无皂聚合和乳液聚合,制备了聚苯乙烯-甲基丙烯酸胶体模板.聚苯乙烯-甲基丙烯酸胶体模板粒径分别控制为363,349,160和56 nm,实现了模板粒径的可控制备.利用制备的聚苯乙烯-甲基丙烯酸系列胶体模板,以偏硅酸钠为前驱体,煅烧去除模板后,制备了不同粒径及壁厚的二氧化硅空心微球.所制备的样品粒径在69～ 405 nm之间,壁厚在11 ～27 nm之间变化.利用扫描电子显微镜、透射电子显微镜和傅立叶变换红外光谱仪,对乳液模板、核壳复合材料及二氧化硅空心球形貌进行了表征,提出了聚苯乙烯-甲基丙烯酸模板与二氧化硅空心微球粒径调控的有效方法.     

Durable, high conductivity, superhydrophobicity bamboo timber surface for nanoimprint stamps

Superhydrophobic bamboo timber was fabricated by magnetron sputtering and nanoimprint stamps. Conductive copper film was deposited on the surface of bamboo timber, followed by transferring lotus leaf structure pattern to the Cu-bamboo timber surface. Modified by stearic acid, the as-prepared surface with lotus leaf structure showed superhydrophobic property with the water contact angle of 152°, and the sliding angle was only 5°. The coating showed excellent mechanical resistance, environmental stability and high conductivity. It was expected that this work could promote the applications of superhydrophobic and conductive bamboo products.     

粗糙群和基于子群的群的粗糙

运用粗糙集理论的思想,在群中基于子群定义了群的近似空间,并定义了集合的运算,用集合的近似进行了研究．用近似群重新定义了粗糙群理论中的粗糙群、粗糙子群、粗糙不变子群、粗糙商群、粗糙同态、粗糙同构等一系列概念,并在传统的和新定义的两种粗糙群理论体系中,研究了基于子群的群的粗糙的性质．     

一类Jacobi矩阵的广义特征值反问题

在综合分析矩阵论中某些反问题和Jacobi 矩阵特征值反问题的基础上, 提出了一类Jocobi 矩阵广义特征值反问题, 给出了问题有唯一解的一个充要条件和解的表达式, 并提供了一个数值例子.     

基于EP1C3T144的最小系统开发板的设计

提出一种新的FPGA最小系统开发板的设计思想,开发板以ALTERA公司的 Cyclone 系列的EP1C3T144为主芯片,配有I/O口、有源晶振、EP1C3T144芯片、电压转换芯片、两个配置接口（JTAG模式和AS模式）和AS串行配置芯片.开发板对I/O口的扩展作了进一步的改进,并以试验DDS为例,对该开发板的应用和功能进行验证.     

基于用户群的智能主题爬虫

提出一个基于用户群的智能主题爬虫系统CITC。它首先对用户群日志进行挖掘,得到相应的知识库。在知识库的指导下,CITC采用多重选择策略,对网页进行选择性爬取。实验结果表明,此系统能够基于用户群兴趣有效地抓取目的网页。