Preparation of ZAO powder and investigation on its infrared emissivity

According to the basic infrared stealth mechanism of low infrared emissivity powders,the ZAO powder materials were prepared by liquid coprecipitation method,and the starting materials were Zn( NO3) 6H2O and Al( NO3) 39H2O. The process parameters were obtained,and the relationship between technology parameters and infrared emissivity was investigated. The temperature of thermal treatment,crystal structure and surface micrograph of ZAO powder was analyzed by the help of TG-DTA,XRD and SEM. The infrared stealth performance of ZAO powder was studied by IR-2 emissivity spectroscopy. Results showed that the infrared emissivity was the lowest when pH was 8. 0,calcination temperature was 1100 ℃,calcination time was 2 h,and the Al2O3doping content was 3% ( mass percentage) . The crystal structure of doped ZAO powder was lead-zinc, and there exists distortion of crystal lattice in nanocrystalline ZnO. The average particle size was 10 μm. The lowest infrared emissivity reached to 0. 61 at between 8 μm and 14 μm. It means that the ZAO powders will be excellent infrared stealthy materials.     

Thermal deformation analysis of the composite material satellite antenna

Controlling the thermal deformation is a crucial index for the design of the satellite antenna. To calculate and measure the satellite antenna’s thermal deformation is also an important step for the design of satellite antenna. Based on the foundation of equivalent assumption, the thermal deformation of the parabolic satellite antenna was analyzed by the finite element method for different design project. The best design project that had the minimum of the thermal deformation could be obtained through changing the lay-angle, lay-layers and lay-thickness of each layer. Results show the asymmetry structure has the minimum of thermal deformation. This paper may provide useful information for the further investigation on the coupling of thermal-stress structure.     

The Negative Thermal Expansion Property of NdMnO3 Based on Pores Effect and Phase Transition

A novel negative thermal expansion(NTE) material NdMnO₃ was synthesized by solid-state method at 1 523 K. The crystal structure, phase transition, pores effect and negative expansion properties of NdMnO₃ were investigated by variable temperature X-ray diffraction(XRD), scanning electron microscope(SEM) and variable temperature Raman spectra. The compound exhibits NTE properties in the orderly O’ phase crystal structure. When the temperature is from 293 to 759 K, the ceramic...     

Surface modification of fire-retardant asphalt with silane coupling agent

The theory and approach of the surface modified of asphalt fire-retardant with silane coupling agent were introduced.The optimum silane dosage was determined,and the structure and properties of the asphalt fire-retardant before and after the surface modification were characterized by infrared spectrum and thermo gravimetric analysis.The dispersion effect of asphalt fire-retardant was studied.The influence of the surface modification on the hydrophilicity and lipophilicity of the asphalt fire-retardant was analyzed.The experimental results showed that there were physical and chemical interactions between the silane coupling agent and the asphalt fire-retardant,which reduced the surface polarity of the asphalt fire retardant.The optimum silane coupling agent dosage was 0.95% of the asphalt fire retardant.The surface modification improved the thermal stability,dispersibility and lipophilicity of the asphalt fire retardant,which enhanced the compatibility between asphalt fire retardant and asphalt.     

Thermal Decomposition Behavior and Kinetics of Composites from Coal and Polyethylene

A thermogravimetric analysis （TG） was conducted to study the thermal decomposition behavior and kinetics of composites from coal and high density polyethylene （HDPE）, linear low density polyethylene （LLDPE） or low density polyethylene （LDPE）. The results show that coal facilitates melting of the polyethylene before temperatures reach 700 K in nitrogen due to the exothermic effect of coal. Above 700 K, adding coal into the polyethylene will result in smaller maximum rates of mass loss and higher initial mass loss temperatures of the composites. Hence, some chemical interactions, occurring between liquid compounds released in the pyrolysis of the coal and polymer, depend on several factors, such as coal rank and the molecular structure of polymers. Synergetic effects in coal and polymers were also found. Both chemical interactions and synergetic effects control the entire thermal decomposition behavior of composites. The larger the amount of coal in the composites, the greater the decomposition temperature spans and the higher the maximum decomposition temperature, the smaller the devolatilization rates. The effect of coal on the thermal stability of composites lies in the hydrogen acceptor effect of the coals. Thermal decomposition of the coals, the polymers and related composites can be modelled via first order parallel reactions between 563 K and 763 K.     

Influence of crystal structure on friction coefficient of ZnO films prepared by atomic layer deposition

In this work, the influence of crystal structure on the friction coefficient of zinc oxide(ZnO) films was studied. The ZnO films were deposited on a Si(100) substrate using an atomic layer deposition process, and the crystal structure of the ZnO films was changed by adjusting the substrate temperature. The surface morphology and the crystal structure of the Zn O films were measured by an atomic force microscope and an X-ray diffractometer, respectively, and the friction coefficient of the ZnO films was measured by a ball-on-disk dry sliding tester. The results show that the ZnO films deposited at substrate temperatures below 200°C are dominated by(100),(002) and(101)-orientated crystals, while the ZnO films deposited at substrate temperatures above 250°C are dominated by(002)-orientated crystals, and that the crystal structure influences the friction coefficient of ZnO films greatly. The ZnO films with(002)-orientated crystals possess a larger friction coefficient than those with other orientated crystals. In order to verify this conclusion, we measured the friction behavior of the ZnO single crystals with different orientations. The results are consistent well with our conclusion.     

Mechanism of low thermal conductivity of xonotlite-silica aerogel nanoporous super insulation material

In an effort to incorporate the low thermal conductivity of the silica aerogel and the superior structure strength of the xonotlite,a composite material of these two was produced. It was synthesized under vacuum condition and dried by supercritical drying technique. The thermal conductivity of the new material,which is at 298K with the gas pressure ranging from 1.01×10^5 to 1×10^-2 Pa,was measured using the transient hot-strip method. The mechanism of the low thermal conductivity was studied. The results indicate that the low thermal conductivity mainly results from the significant decrease of gaseous thermal conductivity of the new material due to the restriction of the motion of gas molecules in its fine structures. The formation of the fine structures is because the new material takes the pore structure of the silica aerogel which consists of mainly nanometer-sized pores.     

Investigation of the Thermal Decomposition Properties of Polyoxymethylene

By testing the melt index （MI）, tensile strength and breaking extension ratio, the thermal ageing rate of polyoxymethylene （POM） was analyzed and compared. The surface morphology and type of function group of POM surface were observed and analyzed by SEM and XPS. The results show that the MI value increases gradually with the ageing time at 120℃, indicating that the thermal oxidation decomposition occurrs slowly. The effect of 20-day thermal ageing on the tensile strength and breaking extension ratio of POM is not obvious, showing that the ageing of POM is quite a long process. After 105-day, thermal ageing cracking and powdering occurr on the POM surface. XPS determination shows the Cls spectra of samples before and after ageing include two peaks of C-C and C-O, while after ageing the content of C-C decreases and the content of C-O increases, indicating that the thermal ageing of POM is mainly the breaking and decomposing of C-C bond. The Ols/Cls ratio of original samples is 56.98% and after 105-day thermal ageing the ratio is 72.92%.     

Effect of thermal oxidation on microstructures and mechanical properties of nanoporous coppers

Nanoporous copper oxides were formed by thermal oxidation of nanoporous copper at 150°C–270°C. The oxidation process of nanoporous copper was investigated by using XRD, SEM, nitrogen adsorption, HRTEM and nanoindentation. The variation of microstructures and mechanical properties was analyzed. The results showed that the content of copper oxides increased, the ligament gradually coarsened, and the mechanical properties of nanoporous structure were improved with the increase of oxidation temperature. When the oxidation temperature was below 210°C, the ligament surface was oxidized to Cu_2O, and the composite structure of Cu_2O@Cu was formed. The formation of CuO occurred since 220°C, and the composite structure of CuO/Cu_2 O@Cu was formed. CuO nanowires were grown on the ligament surface at 250°C; the specific surface area, elastic modulus and hardness of nanoporous structure are 1.37, 3.31 and 7.58 times that of the nanoporous copper, respectively.     

High-temperature phase transition and the activity of tobermorite

The high-temperature phase transition of tobermorite was investigated by TGA/DSC, X-ray diffraction and Infrared spectroscopy(IR), respectively. The experimental results showed that Si-OH bonds were cleaved at 724 ℃ and dehydroxylation occured at the same time, implying that the crystal structure of tobermorite was broken. As a result, the dehydroxylation tobermorite was metastable state, exhibiting obviously hydrolysis activity. The suspension was alkaline and Ca2+ ions content reached a maximum value 4.76% after heat treatment at 724 ℃. The dehydroxylation tobermorite had potential reactive activity due to the strong hydrolysis activity. The disordered structure recombined to wollastonite, and the crystal structure became ordering and stable at 861 ℃. Finally, 2M-wollastonite structure can be found in the sample as the temperature reached up to 1 000 ℃.     

驱动蛋白与微管间阳离子-π和π-π的定量分析

驱动蛋白是一种ATP酶,属于一种在真核细胞中发现的马达蛋白类.驱动蛋白通过ATP的水解供能,能够沿着微管正向运动.驱动蛋白与微管之间存在着阳离子-π和π-π弱相互作用.用Gaussian软件对驱动蛋白与微管之间的阳离子-π和π-π的能量进行量子化学定量计算.根据计算的数据结果,对阳离子-π和π-π分别做了在ATP强结合态和ADP弱结合态两种态下的统计分析,并得到强结合态和弱结合态在总体上能量相差8.32kJ/mol,表明驱动蛋白处于ATP结合态时与微管的相互作用确实强于ADP结合态,这个结果与有关的实验事实定性地吻合.     

一种新型苝衍生物的凝胶行为

采用离子自组装方法,以苝酐的羧酸盐及阳离子表面活性剂二甲基二十八烷基溴化铵（DOAB）为原料,室温下合成一种新型苝衍生物.借用核磁共振仪（NMR）和傅里叶变换红外光谱仪（FTIR）确定目标产物的化学组成和结构.利用透射电镜（TEM）、X射线衍射仪（XRD）、小角X射线散射仪（SAXS）等表征衍生物的凝胶聚集体形貌及排列结构.结果表明：这种苝衍生物能够在芳香环间的π–π相互作用下,通过自组装过程形成有序排列的聚集体,其在甲苯中的凝胶呈现典型的层状结构,苝环之间的π–π相互作用是其形成凝胶的主要驱动力,相互缠结的烷基链与溶剂之间范德华力促使凝胶结构更加稳定.     

配合物[Ho2（bpdc）3·（H2O）4]·5H2O的合成及晶体结构研究

在水热条件下,合成配合物[Ho2（bpdc）3·（H2O）4].5H2O单晶（bpdc为2,2＇-联吡啶-6,6＇二羧酸）.配合物晶体属于三斜晶系,P-1空间群.在晶体结构中含有2种独立配位模式Ho3＋,其配位构型都是八配位的扭曲四方反棱柱体.一种为一个配体H2bipy上的2个氮原子和2个羧基氧原子采用螯合配位占据四方反棱柱体的4个顶点位置,同时余下4个顶点位置被4个配位水分子占据;另一种是2个配体H2bpdc上的4个氮原子与4个羧基上的氧原子配位形成八配位的扭曲四方反棱柱体构型.配合物分子之间通过分子内和分子间的氢键作用与π-π堆积作用进一步形成三维框架结构.     

晶体结构中罕见的O-H…π堆积作用

Hinokiol是一种在植物中含量较少的二萜类化合物，对一些细菌有非常好的杀灭作用。Hinokiol从糙苏（Phlomis umbrosa Turcz）中首次分离出来，利用红外图谱和核磁图谱确定了其结构，并利用单晶X-衍射技术对其晶体结构和构象进行了分析，发现Hinokiol晶体结构中除存在氢键外还存在一种罕见的O-H…π堆积作用，这里对O-H…π堆积作用的特征进行了简单地描述。     

Synthesis and Structural Characterization of [Co（Q）2（H2O）2]（Q=8-Hydroxyquinoline Ion）

8-Hydroxyquinoline(HQ) and its derivatives areof the most intensivelyinvestigatedligands in the co-ordination chemistry[1 -3]. They have been used inmetallic ion detection,chromatography and especiallyin organic light-emitting diodes (OLEDS)[4]. Poly-oxometalates compounds have received muchattentionbecause of their potential applications in catalysis ,sorption, magnetism,photochemistry[5 ,6]. We origi-nally intended to gain the organic-inorganic hybridcomplex of HQ and polyoxometalates . …     

超分子化合物C_8N_2O_2H_6·2H_2O的合成、结构与性能表征

在水热条件下,使用邻苯二胺和草酸合成了一种新的化合物邻苯二草酰胺.通过X-射线单晶衍射技术确定该化合物的结构,该化合物属于三斜晶系,P-1空间群.该化合物结构最显著的特点是存在着具有四水的水簇结构,氢键和π-π作用将该化合物连接成三维的超分子网络结构.用元素分析、红外光谱、紫外光谱对该化合物进行了表征,并测定了其荧光性能.     

均苯四甲酸酯衍生物小分子凝胶剂的合成研究

设计合成了一种新型的以π?π堆积为主导作用力的凝胶因子,通过生成均苯四甲酸酯的形式来减少氢键作用位点,以均苯四甲酸二酐为母核结构与不同碳链长度的醇反应,成功合成了一系列不同碳链长度的均苯四甲酸酯的凝胶因子衍生物,进而探讨了这些凝胶因子衍生物在常见的不同有机溶剂中形成凝胶的性能。流变学测试显示,该凝胶体系的弹性模量比储能模量高一个数量级,有很好的机械性能,并且呈现出典型的类固体的流变学行为。傅里叶红外光谱、核磁共振谱、扫描电镜及DSC结果表明,凝胶中凝胶剂分子形成纤维状的自组装聚集体,以均苯四甲酸二酐为母核结构的凝胶剂分子中π?π堆积的弱相互作用力以及分子间的范德华力是形成该凝胶的主要驱动力,形成的聚集体相互缠绕,最终形成三维网络结构阻碍溶剂流动从而形成凝胶。     

含N杂环硫醚四核Cu(I)配合物的合成及晶体结构

采用溶液扩散法,利用含N杂环硫醚配体2-巯基-(2-甲基吡啶)-4-甲基嘧啶(L)和金属盐CuI反应合成了配合物[Cu4I4L2],利用X线单晶衍射技术测定了其晶体结构,并对其进行了红外表征.结果表明,该配合物属单斜晶系,空间群为P21/n,晶胞参数:a=1.004 70(5)nm,b=0.893 04(4)nm,c=1.815 98(8)nm,β=99.847(10)°,V=1.605 36(13)nm3,Z=2,Mr=1 196.40.该配合物为四核结构,配合物分子间通过氢键、S…S和π-π等弱作用堆积成三维结构.     

Effect of the benzene ring of the dispersant on the rheological characteristics of coal-water slurry: Experiments and theoretical calculations

In this study,low-rank coal-water slurry(LCWS) was prepared using polyoxyethylene dodecylphenol ether(PDPE) and polyoxyethylene lauryl ether(PLE),respectively.A combination of experiments and simulations was used to investigate the pulping properties and microscopic mechanism of the LCWS samples prepared using the two agents,so as to explore the influence of benzene ring on the performance of dispersant.The results of the LCWS preparation experiments revealed that the pulp-forming performance of PDPE exceeded that of PLE.When LCWS concentration is 62%,64%,and 66%,the apparent viscosity corresponding to PDPE is 247.80,504.17,and 653.10 mPa·s,and the apparent viscosity corresponding to PLE is 548.10,1470.61,and 1549.98 mPa·s,respectively.The C_(1000)(When the apparent viscosity is 1000 mPa·s,the corresponding concentration of LCWS is defined as C_(1000)) values of PDPE and PLE are 67.60% and 62.95%,respectively.In addition to the van der Waals forces and hydrogen bonds between the PDPE and/or PLE molecules and coal,the benzene rings of PDPE present π-π stacking effect with the aromatic rings of coal.That could facilitate and strengthen the adsorption of PDPE on coal,which would be conducive to further improving the dispersion of coal particles.The two dispersants have no significant difference in effect on the pyrolysis of LCWS.The simulation results indicated that the times for PDPE and PLE molecules to reach flat adsorption state on coal are approximately 290 and 565 ps,respectively.The self-diffusion coefficient(D) of the PDPE and PLE on coal is 3.16 x 10~(-6) and6.57×10~(-6) m~2/s,respectively,and their interaction energies with coal are 785.71 and 648.60 kcal/mol,respectively.The results of the simulation calculations demonstrated that PDPE adsorbed on coal easier than PLE,and its binding is more stable than that of PLE owing to the π-π stacking effect,which is conducive to uniform dispersion of coal in solution.The simulation results confirmed the experimental results.     

新型含非共轭单元的光伏材料的合成及表征

基于高性能半导体聚合物给体聚［（2,6-（4,8-双（5-（2-乙基己基）-噻吩-2-基）-苯并［1,2-b:4,5-b’］二噻吩））-alt-（5,5-（1’,3’-二-2-噻吩基）-5’,7’-双（2-乙基己基）苯并［1’,2’-c:4’,5’-c’］二噻吩-4,8-二酮）］（PBDB-T）,通过Stile偶联聚合反应,首次合成了一种含非共轭单元的新型聚合物给体材料聚［（2,6-（4,8-双（5-（2-乙基己基）-噻吩-2-基）-苯并［1,2-b:4,5-b’］二噻吩））-（5,5-（1’,3’-二-2-噻吩基）-5’,7’-双（2-乙基己基）苯并［1’,2’-c:4’,5’-c’］二噻吩-4,8-二酮）-1,3-双（2-噻吩基）丙烷］（PDBS-5）,并将其应用于有机太阳能电池。紫外-可见光谱表明:相比于PBDB-T,非共轭单元的引入降低了PDBS-5吸收光谱中堆积峰的吸收强度,表明分子间π-π堆积减弱;循环伏安测试表明非共轭单元的引入降低了聚合物的能级。基于PDBS-5:IT-4F共混膜制备出能量转换效率达到7.42%的有机太阳能电池。研究结果表明含非共轭单元的聚合物PDBS-5是有潜力的有机太阳能电池给体材料。