Pulse width effect on the dissociation probability of CH4^＋ in the intense femtosecond laser field

The electric field strength of the intense ultrashort laser pulse can reach or exceed 108 V/cm, the intensity of the Coulomb field responsible for the stability of molecules. Exposed to such intense laser fields, mole- cules become unstable, undergoing di…     

Fabrication and photoluminescence of GaN nanowires prepared by ammoniating GaeO3/BN films on Si substrate

GaN nanowires were successfully prepared on Si（111） substrate through ammoniating Ga203/BN films deposited by radio frequency magnetron sputtering system. The synthesized nanowires were confirmed as hexagonal wurtzite GaN by X-ray diffraction, selected-area electron diffraction and Fourier transform infrared spectra. Scanning electron microscopy and transmission electron microscopy revealed that the grown GaN nanowires have a smooth and clean surface with diameters ranging from 40 to 160 nm and lengths typically up to several tens of micrometers. The representative photoluminescence spectrum at room temperature exhibited a strong UV light emission band centered at 363 nm and a relative weak purple light emission peak at 422 nm. The growth mechanism is discussed briefly.     

孔隙结构对碎屑储集岩物性控制作用的定量描述

油气储集岩的微观孔隙结构对其物性具有重要的控制作用.通过扫描电镜的直接观察和对应的孔渗物性分析揭示了微观孔隙结构与岩石孔渗性能呈良好的正相关关系.由常规压汞法可以提取多项表征储集层微观孔隙结构的特征参数,使用对应分析数学地质手段筛选出主控因素.通过多元线性回归,获得了储集岩孔隙度、渗透率与其孔隙结构参数之间的定量关系,以及储集岩孔隙度与其孔隙结构参数及矿物组成之间的定量关系.这些定量关系证明了孔隙结构对碎屑储集岩物性的明显控制作用,为储集岩孔渗性能的预测提供了新的手段.     

微乳法与溶剂热法制备WO3/ZrO2及其在异丁烷/丁烯烷基化反应中的应用

采用4组分微乳液为CTAB/正己烷/水/正戊醇体系,溶剂热法制备了WO3/ZrO2固体酸催化剂,并用X射线粉末分析(XRD)、红外光谱、N2吸附-脱附、透射电镜(TEM)等手段对样品结构进行了表征.TEM、氨程序长温脱附(NH3-TPD)和烷基化反应的测定结果表明:ZrO2纳米粒子呈方形,WO3/ZrO2纳米粒子呈球形;样品在负载WO3后经过焙烧酸量大大增强;烷基化产物中C8的质量分数在70%左右.     

FTIR-ATR chamber for observation of efflorescence and deliquescence processes of NaClO4 aerosol particles on ZnSe substrate

NaClO4 aerosol particles with diameter of 5-20 microns are deposited on the ZnSe substrate. An FTIR-ATR chamber on the ZnSe substrate is set up to observe the structural changes of NaClO4 aerosol particles at crystallization relative humidity （CRH） and deliquescence relative humidity （DRH）. With the decrease of RH （relative humidity） from 96% to 24% in the efflorescence process, the absorbance of O-H stretching band of the aerosol solutions continuously decreases. A sudden decrease of the water peak is observed at RH20%, where solid particles form. Very small amount of residual interfacial water, with two weak peaks at 3602 and 3533 cm^-1, can still be resolved in the FTIR-ATR spectra of the solid particles. In the deliquescence process of the same sample, little spectral changes are observed when the value of RH varies from 5% to 29%. Before the abrupt increase of the O-H stretching band at the DRH of about RH46%, a pre-deliquescence process is observed, i.e. in the RH range between 33% and 46%, there is really a slow absorbance increase for the peak area of O-H stretching band. The O-H stretching band shows an arciform O-H en- velope, totally different from not only the FTIR-ATR spectra of ClO4^- solutions either under supersaturated state or in diluted state, but also the characteristic of the residually interfacial water discussed in the efflorescence process. Such kind of water is considered as pure water, indicating that small amount of water aggregates in the microspaces of solid aerosol particles due to the capillary cohesion effect. When the RH arrives at RH44%, two weak shoulders at 3384 and 3260 cm^-1 can be resolved, and the solid NaClO4 particles begin to be dissolved by increasing capillary cohesion water. The spectral characteristic of the v3-ClO4^- band also shows the transition from solid particles to mainly solvated ClO4^- ions.     

产品绿色设计评估建模

绿色设计评估是实施产品绿色设计的关键技术。建立了产品的全生命周期信息模型 ;并在此基础上 ,提出了退役产品的拆卸回收评估方法和产品全生命周期环境影响评估方法 ;探讨了产品绿色设计决策支持系统的框架组成。绿色设计评估系统将产品的拆卸回收分析和产品全生命周期分析结合在一起 ,可为产品的绿色设计提供方案评估和决策支持     

Modeling pyrolysis of charring material in fire

A modified model of pyrolysis for charring materials in fire has been proposed in this note. In this model some special factors which show the effect on pyrolysis are considered, i.e. heat loss by convection and radiation caused by surface temperature rise and shrinkage of char surface are considered. Experimental device is designed specially for validating the reliability of the model. Effects of density of materials and heat radiation on pyrolysis of materials have also been investigated.     

Dissociation of methanol in intense femtosecond laser field

Methanol was irradiated by 80 fs laser pulse, intensity range of 10¹³–10¹⁴ W/cm². A TOF-mass spectrometer was coupled to the laser system and used to detect the ions produced. The parent ions CH₃OH⁺ appeared firstly at the laser intensity of 1.4×10¹³ W/cm². While the laser intensity was gradually increased, the parent ions were dissociated and the primary ions CH₂OH⁺ were given as verified from the irradiation of deuterated methanol (CH₃OD) showing the C—H bond cracking firstly. While the laser intensity was further increased to 2.0 × 10¹³ W/cm², the C—O bonds of the parent ions also broke to give CH₃ ⁺. When the laser intensity was higher, smaller fragment ions like CH⁺, C⁺, OH⁺ and O⁺ also appeared. Among the fragment ions, only H⁺ ion yield had anisotropic angular distribution dependence on the laser polarization vector in the dissociation of methanol. All the experimental observations show that the dissociation of methanol proceeds through stepwise mechanism but not Coulomb explosion.     

分形集上广义s-凸函数的一类带有局部分数积分的Hadamard不等式及应用

利用局部分数积分的分析方法, 给出分形集上广义s-凸函数的Hadamard型恒等式, 进而得到一类Hadamard不等式, 并结合数值积分及几个常用的平均值给出其应用.     

硝化纤维素-甘油-丙酮-苯纳米微滴体系的光谱特性研究

10mg/mL硝化纤维－58．2mg/mL甘油－3mL丙酮－3mL苯体系为白色不透明体系；6．7mg/mL硝化纤维－38．9mg/mL甘油－3mL丙酮－6mL苯纳米微滴体系呈黄紫色；5．7mg/mL硝化纤维－33．3mg/mL甘油－3mL丙酮－7．5mL苯纳米微滴体系呈红紫色；5．0mg/mL硝化纤维－29．1mg/mL甘油－3mL丙酮－9．0mL苯纳米微滴体系呈蓝紫色，它们具有不同的紫外吸收光谱和共振散射光谱。由紫外吸收光谱无法确定纳米微滴的颜色，而共振散射光谱可判定纳米微滴的颜色。根据纳米微粒的界面超分子能带原理解释了纳米微滴体系的呈色现象。