Synthesizing plans that contain actions with context-dependent effects1

This paper presents a method of solving planning problems that involve actions whose effects change according to the situations in which they are performed. The approach is an extension of the conventional planning methodology in which plans are constructed through an iterative process of scanning for goals that are not yet satisfied, inserting actions to achieve them, and introducing subgoals to these actions. This methodology was originally developed under the assumption that one would be dealing exclusively with actions that produce the same effects in every situation. The extension involves introducing additional subgoals to actions above and beyond the preconditions of execution normally introduced. These additional subgoals, called secondary preconditions, ensure that the actions are performed in contexts conducive to producing the effects we desire. This paper defines and analyzes secondary preconditions from a mathematically rigorous standpoint and demonstrates how they can be derived from regression operators.     

基于AutoCAD2000的图解法确定工艺转角

提出了基于AutoCAD2 0 0 0的图解法求解机械加工过程中工艺转角的问题 ,并针对具体的应用实例给出了圆满的解答 ,并验证了其精度。     

影响聚合物段塞流变性因素的研究

本文针对我国表面活性剂/聚合物驱油的实际,研究了石油磺酸盐(PS)、正丁醇(R_4OH)和矿化水对水解聚丙烯酰胺(HPAM)溶液流变性的影响。结果表明,PS对HPAM溶液流变性的影响与介质的矿化度有关:非矿化水介质中,PS对HPAM溶液性质的影响类似于无机盐,能降低HPAM溶液的表现粘度(η_α)和稠度系数(k);当系统中含有一定浓度矿化水时,PS却能升高系统的η_α和k值,降低流型指数(n),使系统的非牛顿性增强。在含有PS和矿化水的HPAM系统中加入R_4OH,系统的η_α和k值会有所增加。     

Boussinesq方程的永形波的级数解

对于用层平均速度势(或速度)与波高给出的非线性等水深Boussinesq方程,与KdV方程一样,存在两类永形波—孤立波和周期波。不同的是,对于Boussinesq方程,孤立波和周期波一样,是以反函数的积分形式给出的,这在使用上是不方便的。本文对这两类波,分别给出了相应的级数形式的正函数解。对于孤立波,级数的收敛速度是十分快的,且文中还给出了一个具有高精度的十分简单的近似解,对于周期波,只要有关参数选得合适,解的收敛速度也是相当快的。这就有效地克服了反函数形式解在使用上的不方便。     

痕量分析中金溶液的稳定性

评述了痕量分析中,金标准溶液和天然水试样中痕量金贮存的稳定性及影响贮存的重要因素,提出了标准溶液配制和贮存的方法。     

发电机同轴励磁机电刷火花过大的原因及处理方法

本文对发电机同轴励磁机电刷火花过大的原因进行了分析．并针对这些原因提出了相应的处理办法。对规范励磁机的运行维护有很大的帮助。     

从混联法生产中提取镓的研究

针对联合法厂家资源的分布特点,提出采用化学法和树脂吸附法相结合的方式实现同时回收烧结法和拜尔法循环母液中镓的新工艺,并通过小试和扩试结果分析,阐述了该工艺的可行性。     

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我国的西气东输工程从新疆塔里木油田到上海，管线长度达4000公里，为确保对长江三角洲地区安全稳定的供气，就必须在长江三角洲地区建设地下储气库，从而保证在管线故障期间应急供气，同时利用地下储气库调节冬季和夏季用气量的差异，保证长输管线的高效、平稳运行。在长江三角洲地区经地库址选择，目前准备将常州盆地的金坛盐矿用以建设地下储气库。盐穴地下储气库主要选择在盐层或盐兵上，利用水溶方式形成地下溶腔进行储气，选择合适的建库地址要结合地质、水、工程等诸多因素，造腔过程中需要采取一系列控制技术，在造腔过程中还要及时采取声纳测井技术进行跟踪监测，造腔过程的检测及腔体完成后的密封安全性检测是气库能否投入运行的关键。     

Second-order Wagner theory of wave impact

The paper deals with the two-dimensional unsteady problem of the impact of a liquid parabola onto a rigid flat plate at a constant velocity. The liquid is assumed ideal and incompressible and its flow potential. The initial stage of the impact is the main concern in this study. The non-dimensional half-width of the contact region between the impacting liquid and the plate plays the role of a small parameter in this problem. The flow region is subdivided into four parts: (i) the main flow region, the dimension of which is of the order of the contact-region width, (ii) the jet-root region, where the curvature of the free surface is very high and the flow is strongly nonlinear, (iii) the jet region, where the flow is approximately one-dimensional, (iv) the far-field region, where the flow is approximately uniform at the initial stage of impact. A second-order solution in the main flow region has been derived and matched to the first-order inner solution in the jet-root region. The matching conditions provide an estimate of the dimension of the contact region for small time. Pressure distributions in both the main flow region and the inner region are derived. The accuracy of the obtained asymptotic formulae is estimated. The second-order hydrodynamic force acting on the plate is obtained and compared with available experimental data. A fairly good agreement is reported.     

Nodally exact Ritz discretizations of 1D diffusion–absorption and Helmholtz equations by variational FIC and modified equation methods

This article presents the first application of the Finite Calculus (FIC) in a Ritz-FEM variational framework. FIC provides a steplength parametrization of mesh dimensions, which is used to modify the shape functions. This approach is applied to the FEM discretization of the steady-state, one-dimensional, diffusion–absorption and Helmholtz equations. Parametrized linear shape functions are directly inserted into a FIC functional. The resulting Ritz-FIC equations are symmetric and carry a element-level free parameter coming from the function modification process. Both constant- and variable-coefficient cases are studied. It is shown that the parameter can be used to produce nodally exact solutions for the constant coefficient case. The optimal value is found by matching the finite-order modified differential equation (FOMoDE) of the Ritz-FIC equations with the original field equation. The inclusion of the Ritz-FIC models in the context of templates is examined. This inclusion shows that there is an infinite number of nodally exact models for the constant coefficient case. The ingredients of these methods (FIC, Ritz, MoDE and templates) can be extended to multiple dimensions