飞参系统实时监视技术研究

针对飞机研制阶段各系统交联试验时故障定位慢、检查测试手段匮乏的问题,设计了飞参系统的实时监视功能。飞参系统中的机载设备与地面设备通过以太网进行数据交互,实现飞机状态的实时监视。分析了实时监视功能的作用与优势,并从某型飞参系统功能需求出发,阐述了机载设备的硬件配置及软件架构。基于UDP通信协议,提出了一种机载设备与地面设备交互的数据收发策略。该策略通过地面设备控制数据通信周期,机载设备采集的数据按周期发送给地面设备还原显示,实现了飞行数据的一边记录一边监视。实际应用表明,飞参系统的实时监视功能丰富了试验测试手段,提高了各个系统试验效率,实现了对飞机实时状态的监测,为航前快速检测技术的发展奠定了基础,具有很高的工程实用价值。     

混合溶剂中混合电解质活度系数的研究——HCl+NaCl+PrOH+H2O体系, 298.15 K

This paper reports our studies on HCl+NaCl+PrOH+H_2O system by mesns of emf measurements of the cell without liquid junction as type (A) Pt, H_2 (latm) |HCI (m_A), NaCl (m_B), PrOH(x), H_2O(1-x)| AgCl-Ag (A) at constant total ionic strengths I=0.1, 0.5, 1.0, 2.0 and 3.0 mol kg~(-1), at 298.15 K, where m_A and m_B are the molalities of HCl and NaCl, respectively, x is the molar fraction of PrOH in mixed solvents, x=0.05. The results show that HCI approximately follows Harned's Rule from I=0.1 to 3.0 mole kg~(-1)...     

Migration-plugging properties and plugging mechanism of microfoam

To gain a better understanding of the migration-plugging properties and plugging mechanism of microfoam, micromodel tests were conducted to investigate the factors controlling the bubble size and plugging mechanism of microfoam. The resistance factor, plugging ratio, and matching factor between average bubble diameter of microfoam and pore-throat diameter of core were introduced to characterize the migration-plugging properties of microfoam by core displacement experiments. The results showed that the average bubble diameter of microfoam could be tuned from 8.6 to 57.9?µm by changing the gas liquid ratio and the sandpack foam generator permeability. Microfoam showed both better injectivity and deep plugging capacity when the matching factor was 1.35–1.87 and the gas liquid ratio was 1:2–1:1. Microfoam would create a temporary blocking zone in the high permeable region through bubble accumulation, and the subsequent microfoam would flow through the low permeable region directly or by means of elastic deformation. With the increase of the gas liquid ratio, the flow pattern of the microfoam was changed from dispersed and isolated bubbles to dense and surface contact bubbles. The blocking mode of microfoam at the pore-throat was shown to shift from intermittent plugging to continuous plugging, leading to the enhancement of plugging capacity and deformability of microfoam.     

OFDM水声通信系统中基于中继选择的资源分配算法

针对水声通信中继系统中系统容量和中继选择问题,本文提出了一种基于中继选择的资源分配算法。首先将每条中继链路的信道增益等效为虚拟直传链路的信道增益,然后在等功率分配的前提下,根据信道信息最佳原则,提出了一种中继选择及资源分配的多用户迭代算法,以实现对每个用户的传输链路进行选择和子载波分配,最后通过线性迭代注水算法进行功率分配。仿真结果表明,所提算法在保证目标速率的前提下,提升了系统容量。     

Transfer Hydrogenation of Ethyl Levulinate to γ‐Valerolactone Catalyzed by Iron Complexes

Conversion of biomass‐derived ethyl levulinate to γ‐valerolactone is realized by using homogeneous iron‐catalyzed transfer hydrogenation (CTH). By utilizing Casey's catalyst and cheap isopropanol as hydrogen source, γ‐valerolactone can be generated in 95% yield. Addition of catalytic amount of base is important to achieve good yield.     

Mechanisms of Enhanced Oil Recovery by Surfactant-Induced Wettability Alteration

Different measurements were conducted to study the mechanisms of enhanced oil recovery (EOR) by surfactant-induced wettability alteration. The adhesion work could be reduced by the surfactant-induced wettability alteration from oil-wet conditions to water-wet conditions. Surfactant-induced wettability alteration has a great effect on the relative permeabilities of oil and water. The relative permeability of the oil phase increases with the increase of the water-wetness of the solid surface. Seepage laws of oil and water are greatly affected by surfactant-induced wettability alteration. Water flows forward along the pore wall in the water-wet rocks and moves forward along the center of the pores in the oil-wet rocks during the surfactant flooding. For the intermediate-wet system, water uniformly moves forward and the contact angle between the oil–water interface and the pore surface is close to 90°. The direction of capillary force is consistent with the direction of water flooding for the water-wet surface. While for the oil-wet surface, the capillary force direction is opposite to the water-flooding direction. The highest oil recovery by water flooding is obtained at close to neutral wetting conditions and the minimal oil recovery occurs under oil-wet conditions.     

Pore-Scale Studies on the Stability of Microfoam and the Effect of Parameters on Its Bubble Size

This paper presents a new method to prepare microfoam with excellent stability and high by using a sandpack foam generator. The micromorphology of microfoam were analyzed, and average bubble diameter and uniformity of microfoam were studied by microscope. The stability of xanthan gum-stabilized microfoam and common microfoam at the pore scale was also compared. The results showed that a highly uniform microfoam ranging in size from 10 to 100 µm in diameter with a variable coefficient less than 10% was successfully prepared. The bubble size of the microfoam could be controlled by solution viscosity, gas and liquid flow rate, temperature, and backpressure. The bubble size of microfoam decreased and became uniform with the increase of solution viscosity, total flow rate, and backpressure. The bubble size increased slightly and became non-uniform with the increase of temperature, while the concentration of foaming agent had little effect on the bubble size when above 5000 mg/L. The xanthan gum in the solution increased the viscosity and thickness of liquid membrane, so xanthan gum-stabilized microfoam maintained better stability within microconfined media than common microfoam under condition of 160 g/L salinity, 90°C, and 6 MPa backpressure.     

KCl在甲醇-非电解质的混合溶剂中溶解度和溶剂化

本文测定了5、15、25和35 ℃时KCl在甲醇-苯、甲醇-甲苯、甲醇-环己烷和甲醇-四氯化碳中的溶解度S, 并得到经验公式: logS=a+bT, 其中T为绝对温度。同时计算了KCl由甲醇到甲醇混合溶剂的标准迁移自由能ΔG_(tr)~°-, 并得到它和组成x_(Ne)的经验关系式; ΔG_(tr)~°-=CX_(Ne)。同时指出在本实验范围内,温度的变化不影响单纯溶剂化模型和第二介质常数公式的适用性。     

Degradation factors of a new long life cathode

This paper analyses the degradation factors of a new long life coated impregnated cathode after accelerated life test. The surface state of the cathode is investigated with scanning electron microscope (SEM) as well as the content and variation of the various elements on the surface and the longitudinal section of the cathode are analyzed with Auger electron spectroscopy (AES) before and after the life test. The analyzing results with SEM show that the cathode coating shrinks at the life end and leads to a rise in its work function. The analyzing results with AES show that the percent of the W increases and the active materials Ba decreases on the cathode surface at the life end. Furthermore, there is less Ba underneath the cathode surface but still a lot of Ba in the tungsten matrix at the life end.