Synthesis and Characterization of Novel Tungsten Phosphates、Sodium Titanium Oxide、Sodium Tin Oxide

水热法和固相法是合成晶体材料的两类重要方法，与常温常压比较,水热条件下物质的理化性能均有很大变化,其间既可能产生新的化学反应,又可以使反应速度大为提高,因此作为制备新材料的强有力手段,水热法被广泛应用于制备超细及异型粉体、新型陶瓷、晶体、复合氧化物、新型结构材料等方面。而固相法由于实验条件易于控制，且可得到高温条件下稳定相等优点是较早应用在晶体合成的方法。本文通过水热法对钨磷酸盐体系，高温固相法对钛酸钠、锡酸钠进行了合成的研究，并利用X射线粉末和单晶衍射法，结合EDX能谱和红外吸收光谱等方法确定了合成产物的结构和化学组成，使用SEM扫描电子显微镜和光学显微镜对晶体形貌进行了观察。共合成和表征了...Hydrothermal synthesis and solid state synthesis are two important methods of crystal material synthesis. In comparison with method in normal temperature and pressure, the physical and chemical properties change much under hydrothermal conditions. Under such conditions, new kinds of reactions could be found and the speed of reaction could be improved perhaps. In this way, hydrothermal synthesis ha...学位：理学硕士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：20032509

Synthesis and crystal structure of Na2TiO3

The crystal structure of a sodium titanium oxide Na2TiO3 obtained by high temperature solid state reaction method was determined from single-crystal X-ray diffraction study. The compound crystallizes in the monoclinic system, space group C2/c, M-r = 141.88, a = 9.885(1), b = 6.4133(8), c = 5.5048(7) angstrom, beta = 115.50(3)degrees, V = 314.99(7) angstrom(3), Z = 4, D-c = 2.992 g/cm(3), lambda = 0.71073 angstrom, mu = 27.80 cm(-1), F(000) = 272, T = 295 K, R = 0.0189 and wR = 0.0512 for 30 variables and 370 contributing unique reflections. The three-dimensional structure in Na2TiO3 is constructed by the TiO(1)(4)O(2) and NaO(1)(3)O(2)(2) groups. The titanium atoms are grouped in the form of trigonal bipyramid and arranged along the c axis by sharing the edges. The structure is compared with other structures of related A(2)BO(3) compounds

高强钢构件稳定性研究最新进展

高强度钢材被越来越多地应用于现代钢结构,例如高层建筑、大跨度桥梁和输电塔中,但构件的稳定问题成为限制其应用的主要因素。详细介绍了国内外学者在高强钢构件稳定性能研究方面取得的最新成果,包括高强钢材料常温静载一次拉伸的力学性能、残余应力测试,以及构件的局部稳定、整体稳定、局部和整体稳定的相关性。同时,指出已有研究存在的问题,为高强钢结构设计及进一步的研究提供参考

Surface-Enhanced Raman Scatting Substrates Fabricated by Combining Chemical Assembly and Electrodeposition Methods

采用一种结合化学组装和电化学沉积制备均匀而且具有强SERS基底的方法,研究了沉积电位对组装在ITO表面的金纳米粒子形貌的影响,发现在-0.04 V下沉积5 min可以得到形貌均匀的纳米粒子.利用现场电化学紫外-可见吸收光谱来监控电化学沉积过程,发现沉积一定时间后,紫外-可见吸收谱在600~700 nm区间出现新峰,表明粒子间发生了有效的电磁场耦合.对制备的基底进行拉曼成像,结果表明,基底的均匀性很好,最强点与最弱点的d信号差小于20%,符合商品化基底的要求.We reported a method to prepare SERS substrates with a high and uniform SERS activity by combining chemical assembly and electrochemical deposition methods.We systematically investigated the effect of the electrode potential on the surface morphology of the Au nanoparticles on the ITO surface.It is found that Au nanoparticles with very uniform structure and proper electromagnetic coupling can be obtained by electrodeposition at-0.04 V(vs.SCE) for 5 min.In situ electrochemical UV-Vis absorption spectroscopy was used to monitor the deposition process by measuring the absorption spectra.A new peak between 600 and 700 nm was observed in the UV spectra during the electrochemical deposition process,which can be used as a measurement of whether and how the electromagnetic field of nanoparticles couples.SERS mapping was performed to demonstrate that the substrate was very uniform with a signal deviation less than 20%,meeting the standard for commercial SERS substrates.国家自然科学基金(批准号:20673086);; 教育部博士点基金(批准号:20040384010);; 新世纪优秀人才支持计划项目(批准号:NCET-05-0564);; 国家“九七三”计划(批准号:2007CB935603)资

河北省天然草地生物量和碳密度空间分布格局

分析不同草地类型生物量与碳密度空间分布特征及其影响因素,揭示草地植物碳库的变化规律,对于了解我国草地生态系统碳汇具有重要意义。2011–2013年以河北省天然草地为研究对象,调查了不同草地类型的地上活体生物量、凋落物生物量和根系生物量以及各组分的碳密度。结果表明:温性草原、温性草甸、温性山地草甸、低地盐化草甸、暖性草丛和暖性灌草丛6种草地类型的总生物量差异显著,其中低地盐化草甸总生物量最高,为2 770.2 g·m~(–2),而温性草原最低,为747.6 g·m~(–2),前者约为后者的3.7倍;地上活体生物量最大的是低地盐化草甸,其次是暖性灌草丛和温性山地草甸,最小的是温性草原,分别为285.0、235.1、203.1和110.6 g·m~(–2);凋落物生物量也是低地盐化草甸最大,其次是温性山地草甸和温性草甸,分别为584.0、187.9和91.0 g·m~(–2)。6种草地类型的根系生物量均大于地上生物量,是地上生物量的1.9–4.3倍,不同草地类型根冠比的平均值为3.1;低地盐化草甸的根系生物量最高,为1 901.3 g·m~(–2),温性草原的根系生物量最低,只有低地盐化草甸的1/3。在各类草地生物量碳密度方面,低地盐化草甸的地上活体碳密度、凋落物碳密度与根系碳密度均为最大,分别为132.7、81.2和705.9 g C·m~(–2)。草地地上生物量、凋落物生物量和根系生物量以及总生物量均随海拔的升高先减少而后增加(p<0.05);草地生态系统总生物量和根系生物量随大于10℃积温的增加先降低而后升高(p<0.01)。该研究中暖性灌草丛多分布在石质山区,土层很薄,植物地上生物量和根系生物量都比土层较厚的草甸草原低。可见,在较大区域比较不同草地类型生物量时,应综合考虑气候、土壤、地理等因素

Surface-enhanced Raman scatting substrates fabricated by combining chemical assembly and electrodeposition methods

We reported a method to prepare SERS substrates with a high and uniform SERS activity by combining chemical assembly and electrochemical deposition methods. We systematically investigated the effect of the electrode potential on the surface morphology of the Au nanoparticles on the ITO surface. It is found that An nanoparticles with very uniform structure and proper electromagnetic coupling can be obtained by electrodeposition at -0.04 V (vs. SCE) for 5 min. In situ electrochemical UV-Vis absorption spectroscopy was used to monitor the deposition process by measuring the absorption spectra. A new peak between 600 and 700 nm was observed in the UV spectra during the electrochemical deposition process, which can be used as a measurement of whether and how the electromagnetic field of nanoparticles couples. SERS mapping was performed to demonstrate that the substrate was very uniform with a signal deviation less than 20%, meeting the standard for commercial SERS substrates