适度出砂技术在海上稠油油田的应用研究

通过理论计算和室内出砂模拟实验,分别从地层出砂、井筒附近防砂以及井筒内的携砂生产三方面时适度出砂开采方式进行了研究.结果表明:地层出砂对储层物性有所改善,不同粒径段颗粒出砂1%后,渗透率增幅为20%左右,其中细微砂粒(<39 μm)的产出对渗透率提高贡献最大,为21,07%-37.60%;防砂管和地层环空间砂粒的堆积对产能影响很大,环空无砂时产能提高1.71倍,但当环空充满砂时产能仅提高14.70%;只有当井筒内的流体流速大于等于砂粒的沉降末速时产出砂才能被携带出井筒.该开采方式在渤海稠油油田得到成功应用.     

基于广义AIC和RPC的OFDM航空信道估计算法

文章通过对航空信道的分析,指出其稀疏信道特征,使用普通算法对此信道进行信道估计会引入高阶矩阵运算,为加快收敛速度、降低实现难度,文中提出了一种利用GAIC(generalized Akaike information criterion)准则和RPC(repeated phase-rotated Chu)训练序列的OFDM航空信道LS(1east squares)估计方法,该方法利用GAIC准则确定信道模型的阶次及抽头位置,为减小信道估计的运算复杂度,引入RPC序列作为训练序列,既满足了LS(least squares)估计,又大大简化了计算复杂度.文章针对具体应用给出文中算法的性能仿真结果,证明了此算法可避免高阶矩阵运算,节约了大量权值可忽略抽头所引入的资源占用和计算量,且显著减小估计误差,可更好跟踪快变的稀疏信道.     

Solidification and crystallization properties of CaO-SiO2-Na2O based mold fluxes

Crystallization properties play an important role in keeping a smooth running of continuous casting process and high sur-face quality of cast strands. To reduce fluorine pollution in slag, a new type of CaO-SiO2-Na2O (CSN) based mold flux was studied. The solidification and crystallization properties, including crystallization temperature, crystallization ratio and solidification minera-graphy, were measured, which were compared with the CaO-SiO2-CaF2 (GF) mold flux. The results show that the crystallization performance is equal to the high fluoride mold powder and CSN can be used for peritectic steel grades sensitive to longitudinal cracking in continuous casting.     

Electrochemical behavior of K3Fe（CN）6 in water-in-oil microemulsion

A water-in-oil (W/O) microemulsion composed of Triton X-100, n-hexanol, n-hexane and water solution with hydrochloric acid was prepared. K₃Fe(CN)₆ was added in as a water-soluble electroactive probe, and its electrochemical behavior was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is found that the H⁺ concentration of the water phase has a great effect on the conductivity of the W/O microemulsion, and hence influences the electrochemical behavior of K₃Fe(CN)₆. When the pH value of water phase is about 7, the electrical conductivity of the W/O microemulsion is only 1.2×10⁻⁶ S/cm, and K₃Fe(CN)₆ almost cannot react at the glassy carbon electrode. But when the H⁺ concentration is more than 3 mol/L, the W/O microemulsion has a good electrical conductivity and K₃Fe(CN)₆ shows good electrochemical performance in it. The results of CV and EIS studies indicate that the electrochemical behavior of Fe(CN)₆ ³⁻/Fe(CN)₆ ⁴⁻ in the W/O microemulsion is different from that in the aqueous solution. This may be due to the unique liquid structure of the W/O microemulsion and the unique mass transfer in the W/O microemulsion. Foundation item: Projects(20673036, J0830415) supported by the National Natural Science Foundation of China; Projects(05JT1026, 2007JT2013) supported by the Science Technology Project of Hunan Province, China     

Wet friction performance of C/C-SiC composites prepared by new processing route

C/C-SiC composites with SiC island distribution were prepared via a new processing route. The fabrication process mainly included silicon infiltration by ultrasonic vibration, chemical vapor deposition (CVD), siliconizing, liquid phase impregnation and carbonization. The wear and friction properties were tested by an MM-1000 wet friction machine. The results show that SiC phases are mainly distributed between carbon fibers and pyrocarbons as well as among the pryocarbons. The dynamic friction coefficient of the composites decreases gradually from 0.126 to 0.088 with the increase of the surface pressure from 0.5 to 2.5 MPa at the same rotary speed. Furthermore, under the constant surface pressure, the dynamic friction coefficient increases from 0.114 to 0.126 with the increase of the rotary speed from 1 500 to 2 500 r/min. However, the coefficient decreases to 0.104 when the rotary speed exceeds 4 500 r/min. During the friction process, the friction coefficient of C/C-SiC composite is between 0.088 and 0.126, and the wear value is zero after 300 times brake testing. Foundation item: Project(2006CB600901) supported by the Major State Basic Research and Development Program of China; Project(0991015) supported by Guangxi Science Found, China; Project(200808MS083) supported by Guangxi Education Department Found     

Alkaline treatment kinetics of calcium phosphate by piezoelectric quartz crystal impedance

Calcium phosphate film was prepared by electrochemical deposition technology. Subsequently, the alkaline treatment process of calcium phosphate film in 0.1 mol/L NaOH solution was monitored on real time by the piezoelectric quartz crystal impedance (PQCI) technique. The variations of morphology and composition for the alkaline treatment products were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD), respectively. The dynamic variations of calcium phosphate can be characterized by the change of equivalent circuit parameters. The results show that the forming process of hydroxyapatite (HA) is composed of three stages: (1) acidic calcium phosphate dissolution; (2) phase transformation; and (3) HA formation. Furthermore, the correlative kinetic equations and parameters are obtained by fitting the static capacitance (C _s)—time curves. Foundation item: Project(2005CB623901) supported by the Major State Basic Research and Development Program of China     

Failure mode and strength anisotropic characteristic of stratified rock mass under uniaxial compressive situation

A stratified rock mass model was founded by FLAC^3D. The failure mode and anisotropic characteristic of strength for stratified rock mass were analyzed. The analysis results show that the numerical simulation can visually reflect the failure modes of rock samples under different inclination angles β of structural plane. The stiffness of rock sample before peak strength changes in the compressive procedure. With the increase of β, the compressive strength σ _c of rock sample decreases firstly and then increases; when β is in the range of 20°–30° and 80°–90°, σ _c has the largest sensitivity to β; while β falls in the range of 30°–70°, σ _c varies little. When ϕ _j <β<90° (β _j is friction angle of structure plane), the results obtained from numerical simulation and theoretical analysis are in almost the same values; while β⩽ ϕ _j or β=90°, they are in great different values. The results obtained from theoretical analysis are obvious larger than those from numerical simulation; and the results from numerical simulation can reflect the difference of compressive strength of rock samples for the two situations of β⩾ ϕ _j and β=90°, which is in more accordance with the real situation. Foundation item: Project (50099620) supported by the National Natural Science Foundation of China     

复合掺杂Nd（III）和Zn（II）非晶态Ni（OH）2电极活性材料的制备及其表征

以NiSO4、ZnSO4和Nd（NO3）3为原料,采用共沉淀快速冷冻法制备出了复合掺杂稀土Nd（III）和Zn（II）的非晶态氢氧化镍粉体材料。测试发现：样品材料微结构无序性强,结晶水含量较高。将样品材料制备成镍电极并组装成MH—Ni电池,在80mA／g恒电流充电5．5h、40mA／g恒电流放电、终止电压为1．0V的充放电制度下,复合掺杂6％Nd（III）和6％Zn（II）样品材料电池的放电平台为1．2624V,放电比容量为343．12mAh／g,远高于目前应用的B-Ni（OH）2电极活性材料的放电比容量。     

蔗糖酯对精炼大豆油氧化稳定性的影响

以不含抗氧化荆的精炼大豆油为原料,研究了加入蔗糖酯对其氧化稳定性的影响,结果表明：在低温时（烘箱法）,HLB13的蔗糖酯具有一定的延缓大豆油氧化的作用,其中0．5‰添加量（质量分数）时延缓氧化效果最好;高温条件下（110℃）HLB13、HLB11、HLB9的蔗糖酯在不同浓度条件下有一定的加速氧化作用．     

基于Adams／Car的汽车平顺性仿真研究

依据多体动力学理论,利用Adams的专业模块Adams／Car建立某型号汽车的整车样机模型,探索进行汽车仿真的途径,进行了直线加减速仿真,将仿真结果与试验结果进行了对比,并做了相应的分析．