影子价格及其在资源配置中的应用研究

为了应用影子价格实现资源在全社会的最优配置,本文通过线性规划的对偶理论和非线性优化问题的Kuhn-Tucker条件揭示了影子价格的本质,在资源配置优化问题中线性规划模型中的影子价格就是其对偶问题的最优解,非线性规划模型中的影子价格就是与最优解相对应的拉格朗日乘数。根据松紧定理解释了资源影子价格与资源限量之间的关系,还对线性规划模型与非线性规划模型中影子价格的不同表现进行了分析。最后阐明了影子价格在资源配置中的应用。     

深水域近水面水下爆炸水柱形态及演变实验研究

 为研究不同起爆深度的水下爆炸水柱形态及演变特征,进行了1 kg球形RDX装药在不同起爆深度下的海上爆炸实验,通过高速摄像机记录装药起爆后水柱的形成和成长过程,获得了喷射水柱形态的演变特征以及水柱高度、直径、水柱突出水面时间等参数的变化规律,并与Cole、Hole和Swisdak等人的研究结果进行对比分析。研究结果表明：对于深水域近水面水下爆炸,水柱以垂直喷射形态为主,当气泡在膨胀阶段到达水面时水柱存在微弱的径向飞散现象;水柱最大高度随起爆深度呈脉动变化,水柱直径随起爆深度线性减小;Swisdak关于水柱最大高度的计算公式不适用深水域近水面水下爆炸情况。     

Bionomic exploitation of a ratio-dependent predator–prey system

The present article deals with the problem of combined harvesting of a Michaelis–Menten-type ratio-dependent predator–prey system. The problem of determining the optimal harvest policy is solved by invoking Pontryagin's Maximum Principle. Dynamic optimization of the harvest policy is studied by taking the combined harvest effort as a dynamic variable. Computer simulations are carried out to illustrate our analytical findings. Biological and bioeconomical interpretations of the results are explained critically.     

Asymptotic analysis for Merton's problem with transaction costs in power utility case

We revisit the optimal investment and consumption problem with proportional transaction costs. We prove that both the value function and the slopes of the lines demarcating the no-trading region are analytic functions of cube root of the transaction cost parameter. Also, we can explicitly calculate the coefficients of the fractional power series expansions of the value function and the no-trading region.     

针孔辅助点投影诊断方法实验研究

针孔辅助点投影背光成像是近几年国外新兴的等离子体诊断技术,在惯性约束聚变相关物理实验诊断中具有重要的应用前景.为验证这一诊断方法的实用性,在神光Ⅱ第九路平台上开展了演示实验.利用激光驱动平面Ti靶获得约4.7 keV的Ti K壳层X射线,在十几微米的针孔约束下作为次级点源并对Au栅格样品投影成像,并用CCD记录.实验成功获得了清晰的样品二维空间分辨的时间积分图像,空间分辨力优于16.1 μm.实验结果表明针孔辅助点投影具有较高的空间分辨力、较大的视场、较高的图像对比度,将成为瑞利泰勒不稳定性研究、激光状态方程研究等物理实验的重要诊断方法之一.     

蒙特卡罗方法在X光源尺寸测量中的应用

 利用蒙特卡罗方法对两种X光源尺寸测量方法狭缝法和刃边法进行了模拟,比较了在不同实验布局条件下的模拟结果,指出X射线的强穿透性对成像具有较大的影响,使狭缝像的底部展宽,影响对光源特性的判断,同时使刃边法的测量精度在一定程度上受对中精度的制约。为减小其影响,在保证不降低图像接收范围、图像对比度以及测量精度的基础上,设计了新的狭缝法实验测量布局,同时建议用ROLLBAR法代替刃边法进行测量。     

The effect of brine salinity on water-in-oil emulsion stability through droplet size distribution analysis: A case study

Water-in-oil emulsion usually forms during waterflooding in some heavy oil reservoirs. The composition and salinity of the injected water critically affect the w/o emulsion droplet size distribution, which control the emulsion stability and emulsion flow in porous media. The aim of the present work is to assess the effect of different sea water salinities on w/o emulsion stability through microscopic imaging. Therefore, w/o emulsions were prepared with different sea water samples, which were synthesized to resemble Persian Gulf, Mediterranean, Red Sea, and North Sea water samples. The results showed that log-normal distribution function predicts very well the experimental data to track the emulsion droplet size distribution, and then it was used for the emulsion stability analysis. It was found that among the four emulsion samples, North Sea emulsion with the lowest NaCl and TDS concentration of 24.12?g/L and 34.44?g/L remained stable up to almost 24 hours, while Red sea emulsion with the highest NaCl and TDS concentration of 32.39?g/L and 41?g/L became unstable after 6-hour period. This indicated that as the brine concentration increases, the w/o emulsion droplets would be larger due to the higher rate of aggregation and coalescence, and the emulsion stability decreases.     

Burning velocity measurements of fluoropropanes by the spherical-vessel method

Burning velocity measurements of six types of fluoropropanes including structural isomers were carried out in order to understand the flammability of hydrofluorocarbons (HFC). The burning velocity (S_u) was determined by applying a spherical flame model to the pressure rise during combustion, which was measured at room temperature and at initial pressures of 80-107 kPa over a wide range of HFC/air concentrations. The maximum S_u of 1-fluoropropane (HFC-281fa), 2-fluoropropane (HFC-281ea), 1,3-difluoropropane (HFC-272fa), 2,2-difluoropropane (HFC-272ca), 1,2,3-trifluoropropane (HFC-263ea), and 1,1,1-trifluoropropane (HFC-263fb) was 35.0, 31.8, 31.9, 21.2, 25.7, and 14.5 cm s⁻¹, respectively. Note that the maximum S_u of HFC-263ea was appreciably higher than that of HFC-272ca, which shows the importance of the F-atom distribution, as well as of the F/H ratio in the HFC molecule. The results of equilibrium calculation for these HFCs showed that S_u is positively correlated with the flame temperature and the concentrations of the active chain carriers H and OH in the flame. We conducted a trial to interpret the magnitude of S_u by means of the effects of substituents for C₁-C₃ HFCs. As a result, it has been found that the order of inhibition efficiency for S_u decreases in the order of CF₃ > CF₂ > CF.     

面向时间敏感型顾客的服务系统速率-成本决策模型

针对一类客户资源集中、时间敏感性强、质量要求高的服务系统决策问题,建立M/M/1排队模型,分析稳定状态下顾客参与服务系统的均衡到达率、服务价格之间的关系以及服务商最优速率.结果表明:服务速率与顾客单位时间等待成本无关,而均衡到达率和服务价格均与顾客单位等待成本呈负相关;当基准服务质量达到一定水平时,企业要提高利润就要追加投资,降低顾客等待效用,提高顾客满意度.     

The numbers of jump layers of boundary value problems in quasilinear differential equations

This paper discusses the numbers of jump layers of boundary value problems in quasilinear differential equations. In addition, the paper gives several examples to explain why the original equation must be rediscussed when the determinate function in reference [1] is always equal to zero.