甲芬那酸包合物和固体分散体的研究

目的　探索将甲芬那酸 (mefenamicacid ,MFA)制成包合物和固体分散体的工艺 ,以增加其溶解度和溶出速率。方法　采用环糊精 (β CD) ,聚乙二醇 40 0 0 (PEG 40 0 0 )为载体 ,以差示扫描量热图谱与甲芬那酸溶出度为指标 ,确定包合物和固体分散体的制备工艺。结果饱和溶液法制成了甲芬那酸 β CD包合物 ,熔融 冷冻法制成了甲芬那酸 PEG 40 0 0固体分散体 ,甲芬那酸包合物、固体分散体的溶解度分别增加 2 .3、3.1倍。正交试验 9组中以下 3组包合工艺为优 :A3 B3 C2 [m(MFA)∶m(β CD) =1∶8,70℃搅拌 2h],A2 B2 C3 [m(MFA)∶m(β CD) =1∶6 ,6 0℃搅拌 4h],A1B3 C3 [m(MFA)∶m(β CD) =1∶4 ,70℃搅拌 4h]。考虑大规模生产宜选择 β CD用量小、包合效果较好的条件 ,又将A1B3 C3进行扩大试验 ,结果表明该工艺条件重复性好。熔融 冷冻法制备PEG 40 0 0 固体分散体可采用 1∶3～ 1∶4量比。结论　将甲芬那酸制成β CD包合物和PEG 40 0 0 固体分散体技术可行 ,均能显著增加其溶解度和溶出速率     

Heterogeneous platoon flow dispersion model based on truncated mixed simplified phase‐type distribution of travel speed

Existing research on platoon dispersion models either describe homogeneous traffic flow feature, or are in lack of analytical solutions. By analyzing the field data, the truncated mixed simplified phase‐type distribution is proved to be capable of capturing the characteristics of heterogeneous traffic flow with an excellent fitting result. In light of this, we derive a generic heterogeneous platoon dispersion model with truncated mixed simplified phase‐type of speed in the forms of integrable functions. Numerical case studies are conducted to compare the performance of the proposed model and the conventional models (i.e., the Robertson model and truncated mixed Gaussian model). The results show that the proposed model not only better captures the platoon dispersion laws of heterogeneous traffic flow, but also presents higher computational efficiency, which provides practical implications on traffic signal control. Copyright © 2017 John Wiley & Sons, Ltd.     

An Approximate Analytical Solution for Grout Transport Modeling： A Case Study in Luling Mining, China

This case study describes the effects of a grouting process developed to decrease groundwater flow exiting from a ruptured mine ventilation shaft lining in Luling coal mine at Huaibei, China. The primary purpose of grouting at this site is to prevent groundwater flow into the mine from adjacent aquifers. The study supports a transport perspective to describe the miscible grout movement, and provides an approximate analytical method to determine grout concentration based on Wilson and Miller's (1978) model. This study shows that the breakthrough curves (BTCs) established from the Wilson and Miller's model match the experimental BTCs obtained from test grouting performed at the site, and Rd a retardation factor of 1.1 is determined. The retardation factor and the BTC are subsequently used to guide the actual production grouting. The monitored result shows that the groundwater inflow at the disrupted ventilation well has been reduced by 47% after drilling and grouting just one borehole. The discharge rate was measured at no more than 4 m3/h after completion of four injection boreholes, which is about 13% of the 30 m3/h before grouting.     

交通突发事件下交通疏散方案设计

交通突发事件极易造成交通拥堵,严重影响城市交通系统的正常运行,应尽快制定与实施交通应急疏散方案。因此,提出一种基于蚂蚁算法优化的多目标交通疏导分配方法,通过蚂蚁算法寻求最优路径,并综合考虑多个目标影响因素,运用多目标交通分配模型生成交通突发事件下的应急疏导分流方案。通过示例仿真分析,验证该方法的可行性和实用性。     

考虑车辆尾气污染暴露的系统网络优化模型

为缓解车辆尾气排放对出行者造成的影响,为交通规划与管理部门提供一种新的规划思路,从交通管理者的角度,以出行者为研究对象,集成高斯扩散模型,建立了考虑尾气污染暴露的系统网络优化模型.利用Matlab和MINOS对非线性模型进行求解,并通过算例验证了模型和算法的有效性,研究结果表明,所建立的模型能够以牺牲系统小部分行驶时间为代价(+10.45%),有效地降低路网中的尾气污染暴露(-41.13%).通过分析比较,系统行驶时间与系统尾气污染暴露之间存在Pareto优化,即决策者可根据规划目的权衡缓解交通拥堵与减少尾气暴露的关系.     

静水压力对壳液耦合系统频散特性的影响(英文)

The effect of hydrostatic pressure on the vibration dispersion characteristics of fluid-shell coupled structures was studied.Both fluid-loaded cylindrical shells and fluid-filled cylindrical shells were considered.Numerical analysis was applied to solve the dispersion equations for shells filled with or loaded with fluid at various hydrostatic pressures.The results for external pressure showed that non-dimensional axial wave numbers are nearly independent when the pressure is below the critical level.The in...     

基于增强鲸鱼优化算法的面波频散曲线反演

增强鲸鱼优化算法是一种新型群体智能优化算法,相比于传统算法,其性能更加卓越。面波频散曲线反演横波速度可以对浅部的地层进行精确刻画,是工程物探领域一种可靠的手段。利用面波可以有效地识别当地层中出现含高速层或含低速层,但是面波频散曲线反演是一个多极值、非线性的问题。使用增强鲸鱼优化算法,相较于传统线性反演,其可以更快速地逼近极值或跳出局部最小值,收敛速度更快,满足工程物探的需求。     

悬移质运动扩散方程的应用

从悬移质运动剖面二维扩散方程出发 ,通过适当假定 ,获得了饱和含沙量垂线分布公式、悬移质运动一维质量守恒方程和剖面二维实用型方程 ;重新定义了“α系数” ,给出了理论计算公式 ,使数值模拟的理论基础和可操作性得到了强化     

Experimental study of the impact of structural geometry and wind direction on vehicle emissions in urban environment

Vehicle emissions inside an urban environment are investigated using a wind-tunnel under neutral atmospheric conditions. The urban environment was formed as street canyon model. The diffusion flow field in the boundary layer inside the street canyon was examined at different locations of varying geometry of the street and wind directions in the downwind distance of the leeward side of the street canyon model. The results show that the vertical velocity increases as the aspect ratio increases and with wind direction increases from θ = 90°. The pollutant concentration increases as the aspect ratio decreases. The pollutant concentration decreases as the wind direction increases from θ = 90°. The pollutant concentration distributions indicate that the variability of the structure, geometry and wind direction inside the street canyon are important parameters for estimating air quality in the urban street canyon.     

激光测距新的近程散射干扰的研究

对激光测距中出现的新的干扰问题进行了研究。分析了干扰现象,确定了干扰产生的原因,提出了消除干扰的方案,解决了存在的干扰问题。新出现的干扰距离是原大气近程散射干扰距离的2.5倍,是由于大气污染严重造成的,采取了时控增益延长法,将近程抑制距离增加2.5倍,较好地解决了干扰问题,且不影响近目标测距。通过试验证明,大气污染造成近程散射干扰增加的观点的正确,采用延长时控增益的方法抑制新的近程干扰是可行的。