以4’-羟基-联苯-4-羧酸和1,3-二(4-吡啶基)丙烷构筑的一维锌配位聚合物的晶体结构与荧光性质

水热条件下采用Zn(NO3)2.6H2O,4′-羟基-联苯-4-羧酸和1,3-二(4-吡啶基)丙烷作为反应物合成出一个新的一维锌金属配位聚合物{[Zn(Hhbc)2(bpp)].H2O}n(1)(Hhbc=4′-羟基-联苯-4-羧酸,bpp=1,3-二(4-吡啶基)丙烷),并分别用元素分析、红外光谱、差热分析、X-射线粉末衍射和X-射线单晶衍射等表征了该结构。晶体结构分析结果表明:化合物1为一维链状锌(Ⅱ)配位聚合物,通过分子间的O-H…O氢键作用,一维链进一步被连接成二维超分子结构。荧光分析表明常温固态下配合物1发射蓝色荧光,荧光寿命为3.08 ns(480 nm)。     

CTAB辅助合成纳米复合材料Ag/ZnO-TiO2及其紫外光催化性能

在模板剂溴化十六烷基三甲基胺(CTAB)的辅助作用下,按nAg∶nZn∶nTi=0.1∶2∶1的物质的量的比,采用溶胶-凝胶再结合程序升温溶剂热法制备了一系列纳米复合材料Ag/ZnO-TiO2(CTAB),并经X射线衍射(XRD)、紫外-可见漫反射吸收光谱(UV-Vis/DRS)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、扫描电子显微镜配合X射线能量色散谱仪(SEM-EDS)和N2吸附-脱附测定等测试手段对不同温度(500、600、700℃)和不同时间(5、7 h)下煅烧得到各产物的组成、结构及形貌等进行了表征。结果表明,该系列复合材料不仅含有ZnO纤锌矿和TiO2锐钛矿结构,同时有部分Zn2TiO4生成,其Ag还以单质形式存在。在CTAB作用下改变煅烧温度和时间可使各产物分别呈现纳米线、纳米球等多种形态,且颗粒分布较均匀。上述各复合材料在紫外光作用下对罗丹明B(RB)的光催化降解结果显示,样品煅烧温度和煅烧时间不同,其活性会发生明显的变化。     

红外光谱法测定异氰酸酯的封闭率

依据Beer-Lambert定律两种基团的吸收值之比与其相应的质量比成比例的原理,采用红外光谱法测定异氰酸酯加成物中两种官能团的吸收值比值,从而测定体系中异氰酸酯的含量,并最终计算出异氰酸酯的封闭率。实验结果表明,红外光谱法测定异氰酸酯的封闭率快速准确。     

三维有序大孔复合材料Bi2O3/TiO2制备与多模式下光催化降解结晶紫

以TiO2为基体,在聚苯乙烯(PS)胶球和EO20PO70EO20(P123)两种模板剂作用下通过溶胶-凝胶及煅烧后处理方法制备了三维有序大孔纳米复合材料Bi2O3/TiO2.经傅里叶变换红外(FT-IR)光谱、X-射线衍射(XRD)、等离子体原子发射光谱(ICP-AES)、紫外-可见漫反射吸收光谱(UV-Vis DRS)、X-射线光电子能谱(XPS)、扫描电子显微镜(SEM)和N2吸附-脱附等物理测试手段对其组成、结构、形貌及表面物理化学性能进行了表征.结果表明,该复合材料晶型结构良好,孔结构排列整齐有序,孔壁呈介孔结构,属于三维有序大孔材料(3DOM).与TiO2相比,3DOM-Bi2O3/TiO2对光的吸收至少红移60 nm,且红移至可见区.在紫外光、可见光以及微波辅助等多模式光催化降解结晶紫的实验中,复合材料3DOM-Bi2O3/TiO2表现出良好的光催化活性,其活性明显高于P25、Bi2O3和Bi2O3/TiO2.同时,该复合材料针对不同类型的染料均表现出较好的紫外光降解效果,且3次循环实验后,依旧保持较高活性.     

One-pot,three component synthesis of novel 5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxylate derivatives by microwave irradiation

An efficient one-pot synthetic method for the highly substituted 5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxylate derivatives has been accomplished via a microwave irradiation of MCRs of various aldehydes, 2-aminothiadiazole, and acetoacetate without any catalyst in acetic acid. This approach provides a convenient one pot method for the synthesis of 5H-[1,3,4]thiadiazolo[3,2-a]pyrimidine-6-carboxylate derivatives.     

具有两种功能性反应的捕食者-食饵系统的定性分析

本文研究了Hanski et al(1991)提出的生态学模型dx/dt=r0x(1-x/k)-cxy/d+x-gx2/(h2+x2);dy/dt=s0y(1-qy/x)。对捕食者既有HollingⅡ型功能性反应,又有HollingⅢ型功能性反应,对食饵来说既有广食者又有专食者,本文将分析Hanski et al(1991)提出的模型的平衡点、极限环和全局渐近稳定性等动力学行为。     

In situ formed silver nanoparticles on glass fibers grafted with polyacrylamide and their antibacterial activity

In this paper, grafted polyacrylamide from the surface of glass fibers was prepared by surface initiated atom transfer radical polymerization in order to control the matrix surface structure and properties. The uniform and stable grafted polymer layer was utilized to prepare silver ions complexes, and then the silver ions were reduced by AlLiH₄ to form in situ silver nanoparticles. The structure, composition, properties and surface morphology of the modified glass fibers were characterized by X-ray photoelectron spectroscopy, fourier transform infrared spectroscopy, thermo gravimetric analysis and scanning electron microscopy. The antibacterial activities of modified glass fibers against E. coli, B. subtilis and S. cerevisiae had been studied respectively by Shake Flask Method. The results show that the antibacterial ratio of Ag nanoparticles loaded glass fibers is significantly improved than that of Ag⁺ loaded, and the highest antibacterial ratio is 72.2% against E. coli.     

Multiwalled‐carbon‐nanotubes‐based matrix solid‐phase dispersion extraction coupled with high‐performance liquid chromatography for the determination of honokiol and magnolol in Magnoliae Cortex

In this paper, multiwalled‐carbon‐nanotube‐based matrix solid‐phase dispersion coupled to HPLC with diode array detection was used to extract and determine honokiol and magnolol from Magnoliae Cortex. The extraction efficiency of the multiwalled‐carbon‐nanotube‐based matrix solid‐phase dispersion was studied and optimized as a function of the amount of dispersing sorbent, volume of elution solvent, and flow rate of elution solvent, with the aid of response surface methodology. An amount of 0.06 g of carboxyl‐modified multiwalled carbon nanotubes and 1.5 mL of methanol at a flow rate of 1.1 mL/min were selected. The method obtained good linearity (r² > 0.9992) and precision (RSD < 4.7%) for honokiol and magnolol, with limits of detection of 0.045 and 0.087 μg/mL, respectively. The recoveries obtained from analyzing in triplicate spiked samples were determined to be from 90.23 to 101.10% and the RSDs from 3.5 to 4.8%. The proposed method that required less samples and reagents was simpler and faster than Soxhlet and maceration extraction methods. The optimized method was applied for analyzing five real samples collected from different cultivated areas.     

基于空气流场压力分析的头盔冲击波防护效能研究

研究典型战斗头盔对爆炸冲击波致颅脑冲击伤的防护效能。首先开展了50 g TNT距有无头盔防护下头部模型1 m处爆炸的抗爆试验,采集了有无防护下头部前额、颅顶、颅后冲击波超压并进行了对比分析;建立了具有典型颅脑结构的头部有限元模型并进行爆炸冲击波加载,对试验工况进行了仿真再现,通过试验结果验证了仿真模型有效性;同时利用数值仿真对不同工况下冲击波流场压力变化规律进行分析;进一步利用数值仿真研究了泡沫衬垫对头盔防护能力的影响。研究结果表明,典型战斗头盔可使前额空气超压衰减为无防护时的54.5%,但是会使颅后空气超压增强为无防护时的2.19倍,对颅后冲击波防护产生负面效果;头盔悬挂中泡沫衬垫能消弱头盔对颅后防护的负面效果,提高头盔对冲击波的防护能力。