水热法合成SnO2微球的酒敏特性研究

采用分析纯的SnCl4 ·5H2O和NaOH为起始原料,在160 ℃温度条件下水热法反应12 h得到SnO2微球.利用X射线衍射仪(XRD)、扫描电镜( SEM)对合成材料的结构、尺寸和形态进行了表征;采用静态配气法测试了材料的气敏性能.研究结果表明:在160 ℃水热条件下一步合成了均分散的SnO2微球,粒径大约为200 nm.用其制作的旁热式气敏元件在5 V工作电压下对0.005%的C2H5OH的灵敏度为8.7,达到了口腔酒精气体浓度检测限度0.008%的要求,并且响应-恢复特性良好.     

Enhancement of gas absorption rate as a function of the particle size in slurry reactors

Exact relationships are given for the enhancement of gas absorption rate as a function of particle size in a three-phase slurry reactor. The solid-liquid mass transfer in the liquid film at the gas-liquid interface is considered as a transfer through spherical surface. The solid phase is the catalyst or reactant. The enhancement of the gas absorption rate calculated by the given equations are in very good agreement with the experimental data as a function of particle size and solid phase concentration.     

Thermal decomposition of energetic materials 12. Infrared spectral and rapid thermolysis studies of azide-containing monomers and polymers

The IR spectra of the monomers and homopolymers of glycidyl azide (GAP), 3-azidomethyl-3-methyloxetane (AMMO), 3,3-bis(azidomethyl)oxetane (BAMO), 3-azidooxetane (AZOX), and 3-(2,3-diazidopropoxymethyl)-3-methyloxetane (DAPMMO) were assigned. Rapid-scanning Fourier transform infrared spectroscopy (10 scans s⁻¹) was used to characterize the slow (5K min⁻¹) and rapid thermolysis (50–255K s⁻¹) of these compounds. The azide group decomposes before the polymer backbone does. However, once decomposed the products are essentially a mixture of those expected of low-membered cyclic ethers and methyl azide. The gaseous decomposition product concentrations are strikingly insensitive to the applied pressure (1–1000 psi Ar) and to the heating rate (50–255K s⁻¹). HCN is the dominant IR active product in all cases except for AMMO monomer, where CO is more abundant. AMMO polymer is the most thermally stable of the polymers.     

TiO2光催化抗菌陶瓷的制备

制备了SiO2-Zr3(PO4)4改性的TiO2粉体,将其添加到陶瓷釉料中,研制出了TiO2光催化抗菌陶瓷,分别就改性TiO2粉体的光催化活性和TiO2光催化抗菌陶瓷的光催化抗菌机理进行了研究.研究表明,37.2%Zr3(PO4)4和11.5%SiO2改性的TiO2粉体经1323K处理后,仍具有较好的光催化活性,将其添加到陶瓷釉料中制备出的TiO2先催化抗菌陶瓷对大肠杆菌的抑菌率达98%.     

Effect of doping cobalt on the micro-morphology and electrochemical properties of birnessite MnO2

Birnessite-type MnO₂ nanoparticles are synthesized by mixing KMnO₄ solution directly with ethylene glycol under ambient conditions. When cobalt exists in the solution, the micro-morphology of the products transforms from conglomeration to dispersive state. The result of transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) shows that the product is constructed with nanosphere in sizes of ca. 40 nm. These nanospheres are twisted by nanorods clusters. X-ray diffraction (XRD) pattern shows that the products are birnessite-type. The electrochemical properties of the prepared materials are studied using cyclic voltammetry (CV) and galvanostatic charge–discharge test in aqueous electrolyte. The product shows a very high specific capacity of 326.4 F g⁻¹. These results indicate that cobalt has great effects on the micro-morphology and electrochemical properties of manganese dioxide.     

Soot particle inception kinetics in a premixed ethylene flame

In this paper we describe our measurements of the soot particle inception (“nucleation”) rate in an atmospheric pressure premixed flat flame. After demonstrating that interfering optical signals from molecules in the flame could be eliminated or accounted for, we were able to use laser light scattering and extinction to detect the soot particles. An aerosol dynamics model was developed to allow interpretation of the optical data, and an efficient technique was found to solve the differential equations. From their solutions we determined that the soot particle inception rate in our flame peaked near 10¹⁶ cm⁻³ s⁻¹. Net surface growth during the particle inception process was close to zero, possibly because the soot was also being oxidized. The particle inception process lasted for about 2.5 ms. We carried out a sensitivity analysis to evaluate the effects of uncertainty in the properties of incipient particles.     

Water-Soluble,Alanine-Modified Fullerene C60 Promotes the Proliferation and Neuronal Differentiation of Neural Stem Cells

As carbon-based nanomaterials, water-soluble C₆₀ derivatives have potential applications in various fields of biomedicine. In this study, a water-soluble fullerene C₆₀ derivative bearing alanine residues (Ala-C₆₀) was synthesized. The effects of Ala-C₆₀ on neural stem cells (NSCs) as seed cells were explored. Ala-C₆₀ can promote the proliferation of NSCs, induce NSCs to differentiate into neurons, and inhibit the migration of NSCs. Most importantly, the Ala-C₆₀ can significantly increase the cell viability of NSCs treated with hydrogen peroxide (H₂O₂). The glutathioneperoxidase (GSH-Px) and superoxide dismutase (SOD) activities and glutathione (GSH) content increased significantly in NSCs treated even by 20 μM Ala-C₆₀. These findings strongly indicate that Ala-C₆₀ has high potential to be applied as a scaffold with NSCs for regeneration in nerve tissue engineering for diseases related to the nervous system.