GPS信号自适应抗干扰系统

针对GPS卫星信号易受干扰,不稳定的问题,提出INS/GPS组合导航抗干扰的方法并用硬件电路进行实现验证。给出了惯性器件的误差模型,采用松散组合方式,设计卡尔曼滤波器,取姿态、速度、位置的误差作为状态变量。提出以INS与GPS输出的东北天向速度误差作为滤波器观测量的方案。通过计算机的仿真和实验验证,对系统的精度进行了分析,证明该方案是可行的,实现实时滤波计算,并能满足导航的精度要求。     

石油类危化品实时巡检系统

提出了基于GIS、GPS、GPRS和无线传感网络技术的石油类危险化学品油气管道监控系统结构及该系统的软件架构和功能设计.该系统利用无线传感网络、GPS和GPRS技术对油气管道进行实时跟踪巡检预警,利用地理信息系统实现对石油类危险化学品查询、综合分析、动态管理等功能,从而为石油类危险化学品安全监测提供科学依据,对减少事故发生或伤亡损失具有重要的现实意义.     

Note: Autoignition Temperature of Selected Polymers at Elevated Oxygen Pressure and Their Heat of Combustion

Autoignition temperature and heat of combustion are two important parameters in determining the oxygen compatibility of materials. This study investigates the autoignition temperature of 32 polymers at an elevated oxygen pressure of 10.3 MPa and reports their heat of combustion. © 1996 by John Wiley & Sons, Ltd.     

Burning behaviors of selected chlorosilanes and SiH‐containing siloxanes

Chlorosilanes are silanes containing the Si‐Cl functional group and SiH‐containing siloxanes are siloxanes containing the Si‐H functional group. Some chlorosilanes and SiH‐containing siloxanes present potentially high fire or explosion hazards during handling, storage, transport and process operations. Cone calorimeter tests have been used to study the burning behaviors of selected chlorosilanes and SiH‐containing siloxanes at various incident heat fluxes to simulate pool fire burning. The peak heat release rate of a silicon intermediate obtained from the cone calorimeter at 15 kW/m² incident heat flux was very close to that measured by a relatively large‐scale field test. The flammability of monochlorosilanes was similar to that of organic hydrocarbons having comparable volatility. The flammability of chlorosilanes descends in the order of monochlorosilanes, dichlorosilanes and trichlorosilanes. SiH‐containing siloxanes ignited faster than non‐SiH‐containing siloxanes because of the reactive silicon‐hydrogen linkages. The ignition of SiH‐containing siloxanes was much more violent than the ignition of non‐SiH‐containing siloxanes. The SiH‐containing siloxanes exhibited a lower peak heat release rate, less total heat released and a lower peak smoke extinction coefficient compared with non‐SiH‐containing siloxanes having comparable volatility. Copyright © 2004 John Wiley & Sons, Ltd.     

Predicted heats of combustion of some important organosilicon intermediates

This short communication presents the predicted heats of combustion of 308 organosilicon intermediates. The net and gross heats of combustion were predicted using two previously developed empirical equations. These intermediates cover most of the important organosilicon compounds that are manufactured or used in the silicone industry. Copyright © 2003 John Wiley & Sons, Ltd.     

Flammability testing of pure and flame retardant-treated cotton fabrics

A Controlled-atomosphere cone calorimeter was used to investigate the burning of pure and flame retardant-treated cotton fabrics. The condensed-phase flame retardants used were Morguard (containing ammonium dihydrogen phosphate and diammonium hydrogen phoisphate) and Nochar (containing ammonium sulfate and a sodium salt). The fabrics were tested at 25 kW m^?2 incident heat flux in environments containing 15–30% oxygen. The flame retardants increased the time to ignition, residue yield, and CO and CO₂ yields. The flame retardants decreased the peak and average mass loss rates, the peak and average heat release rates, the effective heat of combustion at peak heat release rate, and the propensity to flashover. The effect of oxygen concentration on the burning of pure and flame retardant-treated cotton fabrics has also been investigated. The flame retardants had better performance when the treated fabrics burned in the lower oxyge concentrations. The result of this study indicate that the controlled-atmosphere cone calorimeter is a good tool for studying the effect of flame retardant and oxygen concentration on the burning of materials.     

Thermodynamic and molecular insights into the absorption of H2S,CO2, and CH4 in choline chloride plus urea mixtures

Deep eutectic solvents (DESs) are a class of promising media for gas separation. In order to examine the potential application of DESs for natural gas upgrading, the solubilities of H₂S, CO₂, and CH₄ in choline chloride (ChCl) plus urea mixtures were measured in this work. The solubility data were correlated with Henry's law equation to calculate the thermodynamic properties of gas absorption processes, such as Henry's constants and enthalpy changes. Grand-canonical Monte Carlo simulations and quantum chemistry calculations were also performed to examine the mechanism of gas absorption processes. It is found that the absorption of H₂S in ChCl + urea mixtures is governed by the hydrogen-bond interaction between Cl of ChCl and H of H₂S, whereas the absorption of CO₂ and CH₄ in ChCl+urea mixtures is governed by the free volume of solvents. Based on the different behavior of gas absorption, high H₂S/CO₂, H₂S/CH₄, and CO₂/CH₄ selectivities can be achieved by adjusting the ratio of ChCl/urea in mixtures.     

Zeolitic imidazolate metal organic framework-8 as an efficient pH-controlled delivery vehicle for zinc phthalocyanine in photodynamic therapy

To improve the aqueous solubility and cancer targeting of the photosensitizers in photodynamic therapy (PDT), we encapsulated the photosensitizer in a biocompatibility and pH-sensitive drug delivery system, zeolitic imidazolate frameworks-8 (ZIF-8) nanospheres. Powder X-ray diffraction and electron microscopy show that our nanospheres are uniform and single-crystalline particles. Owing to the cleavage of zinc–ligand coordination bonds, more ZnPc–COOH were released much faster in the mild acidic conditions (pH 5.0 and 6.0) in comparison with physiological environment (pH 7.4). By incorporating ZnPc–COOH in ZIF-8, our nanospheres exhibited high singlet oxygen quantum yield and intracellular ROS generation. Cell viability experiments toward HepG2 cells demonstrated the low toxicity of ZIF-8 and the good anticancer efficacy of the nanospheres with low IC₅₀ values (4.2–4.9 μg/mL) under light illumination (670 nm, 1.5 J/cm²). Collectively, these results suggested that our nanospheres are the promising pH-responsive drug delivery systems for PDT.     

Probing substrate influence on graphene by analyzing Raman lineshapes

We provide a new approach to identify the substrate influence on graphene surface. Distinguishing the substrate influences or the doping effects of charged impurities on graphene can be realized by optically probing the graphene surfaces, included the suspended and supported graphene. In this work, the line scan of Raman spectroscopy was performed across the graphene surface on the ordered square hole. Then, the bandwidths of G-band and 2D-band were fitted into the Voigt profile, a convolution of Gaussian and Lorentzian profiles. The bandwidths of Lorentzian parts were kept as constant whether it is the suspended and supported graphene. For the Gaussian part, the suspended graphene exhibits much greater Gaussian bandwidths than those of the supported graphene. It reveals that the doping effect on supported graphene is stronger than that of suspended graphene. Compared with the previous studies, we also used the peak positions of G bands, and I_2D/I_G ratios to confirm that our method really works. For the suspended graphene, the peak positions of G band are downshifted with respect to supported graphene, and the I_2D/I_G ratios of suspended graphene are larger than those of supported graphene. With data fitting into Voigt profile, one can find out the information behind the lineshapes.     

Experimental study on the radiative ignition of silicones

Silicones comprise a wide variety of materials such as fluids, elastomers, resins, and foams. This paper reports the ignitability of some typical silicones under various external radiant heat fluxes. The ignitability of silicones was studied using a cone calorimeter under radiant heat flux levels of 0.5–60 kW m⁻². The time to ignition of the silicones was found to be proportional to a power of the incident heat flux that varies from −1.33 to −2.84. For silicone fluids, viscosity (or molecular size) is the key variable in controlling the ignitability. For silicone elastomers, the fillers play an important role in controlling the ignitability, especially at incident heat fluxes lower than 35 kW m⁻². The ignitability of silicone resins depends on the chemical structure of the resins: the pure trifunctional resin has the lowest ignitability. The ignitability of the silicone foams having the same density depends on the foam thickness, especially at incident heat fluxes lower than 30 kW m⁻². © 1998 John Wiley & Sons, Ltd.