空间光通信ATP系统粗跟踪平台的混合自适应控制

ATP系统的粗跟踪平台外框架对内框架的耦合作用以及内框架自身的不平衡所引起的加速度干扰是影响空间光通信系统光信号跟踪性能的重要因素。针对方位跟踪通道中的内框架系统结构,提出了应用一种混合自适应控制方法,该方法在设计自适应控制器时采用离散与连续相结合的方法,并将耦合作用和加速度干扰转换为对象的未建模动态进行处理。最终的仿真结果表明,被控对象在具有未建模动态和干扰的情况下,采用混合自适应控制算法能够获得较高的跟踪精度。     

Degradation of p-nitrotoluene by O3/H2O2 process and oxidation mechanism

The degradation of p-nitrotoluene by O3/H2O2 process in a bubble contact column was investigated. Effects of the molar ratio of hydrogen peroxide to ozone,pH value and t-butanol on the oxidation process were discussed. It was found that the proper H2O2/O3 molar ratio for the degradation of p-nitrotoluene was around 0.6, different pH values and the presence of t-butanol highly influenced the removal efficiency of p-nitrotoluene. 5-methyl-2-nitrophenol, 2-methyl-5-nitrophenol, (4-nitrophenyl) methanol, 5-(hydroxymethyl)-2-nitro phenol, acetic acid, 2-methylpropane diacid and 2-(hydroxylmethyl)propane diacid were identified as degradation intermediates and products through GC-MS. Radical reaction mechanism and degradation pathway were proposed based on the results of experiments. It is deduced that the benzene ring of p-nitrotoluene can be only destroyed by hydroxyl radicals through a polyhydroxy intermediate pathway. Then unstable polyhydroxy intermediates can be oxidized to different acids with low molecular weight rapidly.     

Electroless nickel plating on the surface of carbon fibers

The electroless nickel plating on the surface of carbon fibers was prepared by pretreating the carbon fibers in order to increase their conductivity,and consequently enhance the EMI shielding effectiveness of the composites.The relationship between the performance of depositing coat and pH value,temperature,reaction time and the way of agitation was studied.Results show that the depositing quality is stable under pH between 4.5 and 5.0,temperature between 75 ℃ and 85 ℃,reaction time for 10 min and air agitation.The uniform and compact nickel layer deposited on carbon fibers was proved by XRD and SEM,and the electrical resistivity of carbon fibers with nickel coating was tested.Results indicate that the electrical resistivity of carbon fibers with electroless nickel plating is decreased by an order of magnitude compared with that of carbon fibers.It means that nickel coating can greatly improve the electromagnetic interference shielding properties of carbon fibers.     

A preliminary study on total removal efficiency of organic pollutants in sewage by Harbin municipal sewage treatment plant

To evaluate the removal efficiency of organic pollutants in the sewage by Harbin municipal sewage treatment plant,the influent and effluent samples from the plant were pretreated by liquid-liquid extraction (LLE) under conditions of acidity,neutrality and alkalescence in sequence,and then were analyzed by gas chromatograph-mass spectrum (GC-MS) procedures.Results indicate that there are 70 species of organic pollutants in the influent sample of the plant,which mainly consist of alkyls,benzene series,esters,and heterocyclic compounds.Some of these organic pollutants are biotoxic and belong to persistent organic pollutants (POPs).Four species among them are on the list of Prior Pollutants of Environmental Protection Agency of USA (USEPA).However,7 species of organic pollutants appearing in the effluent sample mainly include alkyls of multi-carbons and phthalate esters.The removal efficiency of phthalates is poor because of their poor biodegradability.The sewage treatment technique is effective in removing most of organics pollutants.     

Comparative study on photocatalytic properties of TiO2 nanoparticles prepared in acidic medium and basic medium by hydrothermal method

In order to investigate the difference of phtotocatalytic properties of TiO2 samples prepared in different pH conditions,TiO2 nanoparticles were prepared in acidic medium and basic medium by a hydrothermal process,respectively.The samples were characterized using XRD,TEM,BET,XPS,surface photovoltage spectroscopy (SPS) and field-induced surface photovoltage spectroscopy (FISPS).Effects of temperature and pH in the hydrothermal process on particle sizes,specific surface areas,and photocatalytic properties of the TiO2 nanocrystalline were investigated.The experimental results indicate that the photocatalysis activity of TiO2 nanoparticles prepared in basic medium (B-TiO2) is superior to that in acidic medium (A-TiO2),which is ascribed to the difference of surface state between A-TiO2 and B-TiO2.     

An improvement to the simulation of phase-change heat-transfer during soil freezing and thawing

A new variable time step method, which is called the backwards calculating time step method, is presented in this paper. It allows numerical simulation of soil freezing and thawing while avoiding "phase change missing and overflowing". A sensitive heat capacity model is introduced through which the calculation errors are analyzed. Then the equation using the self-adjusted time step is presented and solved using finite differences. Through this equation, the time needed for a space cell to reach the phase change point temperature is calculated. Using this time allows the time step to be adjusted so that errors caused by "phase change missing and overflowing" are successfully eliminated. Above all, the obvious features of this method are an accelerated rate for adjusting the time step and simplifing the computations. An actual example proves that this method can accurately calculate the temperature fields during soil freezing and thawing. It is an improvement over traditional methods and can be widely used on com- plicated multi-dimensional phase change problems.     

调剖措施效果的模糊理论评价

针对以往对油田调剖措施效果的生产动态资料、水驱曲线、监测资料和经济效益等单因素评价方法结论不够全面的缺点,把它们指标细分,分别对其进行模糊评判,再采用层次分析法确定指标权重,应用模糊综合评价方法对调剖措施效果进行全面的评价,形成一套调剖效果评价标准。用该方法对北三东区块进行评价,得到结果表明,调剖措施模糊综合评价结论客观地反映调剖措施的效果,避免了单因素评价的片面性,全方面反映各指标水平,使措施效果评价系统化,定量化以及标准化。     

金属磷酸盐Al8P2O16（OH）4C3N2H6·H2O的水热合成及晶体结构

采用水热合成的方法,在酸性条件下合成出一个三维微孔化合物Al8P2O16（OH）4C3N2H6·H2O并对其进行了X射线单晶衍射的测定,晶体学数据为：Imma空间群,a=18．655（2）nln,b=8．5370（10）nm,c=13．2196（16）nm,V=2105．3（4）nm^3,a=90°,Z=2,R1=0．0937。     

火灾时钢筋混凝土板的承载力计算

提出了2种能考虑火灾时钢筋混凝土板薄膜效应的极限承载力计算方法。在塑性铰线理论的基础上,利用板块平衡法和虚功法对火灾时钢筋混凝土板的承载力进行了计算,并将计算结果与试验结果进行了对比。结果表明：承载力计算结果与试验结果吻合良好;提出的方法适用于各向同性和各向异性配筋的方形板和矩形板;采用该方法可以解释相同条件下方形板和矩形板产生的破坏挠度不同的原因。     

一种带有纽结分支的内在链图

针对于Petersen图P9进行研究,利用两个Petersen图K3,3,1与中间边组成的图的方法来形成petersen图中的P9,本文得到了一种带有纽结分支的内在链图H（93）,并证明了该定理.