河口近岸区三维潮流及悬沙扩散的一种分步模型

在建立模型时，对三维浅海流体动力学方程进行时间分步计算．在垂直方向上引用σ坐标变换，并采用隐式有限差分格式；在水平方向上，采用迎风有限元方法进行数值离散．应用本模式与相应的理论公式做了对比计算。

口腔固定修复工艺技术实训课教学中分步模型的应用

口腔固定修复工艺技术实训课中应用分步模型是对教师分组示教的传统教学模式的有益补充,有助于学生标准化操作技能的训练和学习兴趣的提高,收到良好的教学效果。

浅谈分步模型在“口腔修复学”教学中的应用

分步模型在口腔修复学中的应用充分弥补了传统教学方法在口腔修复学中的缺陷。在教学过程中,通过分步模型将教学内容完美地呈现出来,提高了口腔修复学的教学效率。

轴入式旋风分离器分步湍流模型的数值模拟与试验

针对轴入式旋风分离器的气相流场,提出了一种基于RNGκ-ε模型和雷诺应力模型的分布湍流模型并进行模拟研究.首先对5种分离器模型的气相流场采用RNGκ-ε模型进行模拟.待气相场趋于稳定时,加入离散颗粒相,对气相改用雷诺应力模型模拟;根据已得到的流场对颗粒相采用随机轨道模型,分析分离器阻力与效率性能.最后将典型模型的模拟结果与试验结果进行比较,二者吻合良好.基于分步湍流模型的数值模拟方法在研究轴入式旋风分离器的气相流场是可靠的.

基于Three.js的交互式鱼类模型展示系统设计

目前浏览器对三维图形显示技术越来越成熟,使用WebGL的第三方库Three.js展示鱼类3D模型不仅简单方便,而且跨平台优势明显。通过对Three.js的研究解决以往技术建立鱼类3D展示系统功能较少、构建复杂、需要安装插件浏览和无法跨平台使用的问题,可推动鱼类可视化的相关应用。本研究主要采取3ds MAX软件建立鱼类模型和标本馆模型,通过Three.js库实现对模型的加载和交互,并将Three.js与Bootstrap框架、PHP技术、MySQL等技术结合进行搭建鱼类模型展示系统。在完成系统构建后将系统部署到腾讯云服务器中完成性能测试。结果显示:本系统实现了鱼类模型搜索查看、分页展示、在线上环境中秒加载,鱼类标本馆场景模型的分步加载,Mobile VR方式查看鱼类模型,以及用户在线上传模型、展示模型、分享模型等功能,具有较好的应用价值。本研究可为鱼类建模、鱼类3D模型的压缩、渔业大型模型场景加载和渔业可视化相关的研究提供参考。

气体泄爆压力分步计算模型及其湍流修正

通过将密闭空间内爆燃泄放过程进行微分,假设各微分时段内爆燃泄放过程均按照先燃烧、再泄放、最后压力平衡的过程独立分步进行,最终得到泄爆压力分步计算模型。同时,在尺寸为2 m×1.2 m×0.6 m的爆炸腔体一端安装击穿压力相同、泄放面积不同的泄爆构件进行泄爆实验,对分步压力计算模型进行验证。对比发现:大面积泄放条件下,2个传感器测得的压力曲线基本重合,均为单峰值曲线,此时模型计算值与实验结果吻合较好;小面积泄放条件下,腔体内压力曲线均为双峰值曲线,由于泄放截面改变加剧口部湍流扰动,使得腔体内部产生压力梯度,近泄爆口处传感器测得的第2个压力峰值要大于腔体内部传感器相应的测量值,经湍流速度修正后的压力计算模型可以较好地描述近泄爆口处的压力变化情况。

基于分布优化模型的穿越沙漠游戏攻略

穿越沙漠游戏非常有趣,受资金、水、食物及天气的限制,成功完成游戏有一定的困难。本论文根据游戏的不同设定,建立穿越沙漠游戏的数学模型,得到行动路线最优策略。对于第一关,首先,以剩余资金为目标函数,以水、食物及天气为约束条件,分别建立不经过矿山到达终点和途径矿山到达终点的最优策略模型。然后,通过比较剩余资金,得到最优路线为1→5→6→13或1→4→6→13,且在初始起点备54箱水和食物。对于第二关,首先,根据沙暴出现的概率,建立路线分步优化模型,利用决策树算法,得到不同沙暴出现次数的最优策略。最后,给出一般情况下玩家的最佳策略(见表1)。

外商直接投资与广东省经济增长的实证分析

通过格兰杰因果检验、多元滞后分步模型等计量经济学方法对1979—2008年间FDI与广东省经济增长之间的关系进行实证分析,结果表明外商直接投资与广东经济增长之间存在着单向的因果关系,即FDI是广东省经济增长的格兰杰原因。

外商直接投资与广东省经济增长的实证分析

通过格兰杰因果检验、多元滞后分步模型等计量经济学方法对1979年～2008年间FDI与广东省经济增长之间的关系进行实证分析,结果表明外商直接投资与广东经济增长之间存在着单向的因果关系,即FDI是广东省经济增长的格兰杰原因。

基于有限量测数据的主动配电网电压暂降源精确定位策略

准确定位电压暂降源,对提高供电可靠性、明确供需双方责任具有重要意义。目前,基于有限电能质量(PQ)监测点量测数据和配电自动化提供的网络实时信息,通过短路电流计算,进行配电网电压暂降源精确定位成为研究热点之一。但现有方法存在不区分暂降源类型,需遍历所有母线、计算量大、过渡电阻估计不准确影响定位精度、难以适用于多源主动配电网等不足。该文提出一种适用于主动配电网的电压暂降源精确定位策略。针对基于序功率增量方向原理确定的暂降源候选区域,进行电压暂降成因辨识。对于由短路故障引起的电压暂降,基于考虑分布式电源接入和过渡电阻影响的主动配电网短路电流计算方法,以故障位置、过渡电阻为优化变量,以最小化有限观测点处故障电流、电压的计算值与观测值误差为目标,建立寻找最邻近母线和寻找准确故障位置的分步优化模型并采用智能优化算法求解,实现精确定位。基于改进IEEE 34节点配电网算例验证了本文方法的有效性,并通过与现有方法的结果比较说明了所提方法的优越性。

题库智能化组卷的心理计量理论与方法

现代教育成就测验的广泛应用，促使题库技术迅速发展。现代教育测量理论与计算机技术的结合，更使智能化组卷成为可能。本文报告了以项目反应理论为指导，并改进一般线性规划法为分步离差加权模型法，编制程序在高等教育自学考试“逻辑学”题库上，成功实现智能化组卷的研究成果，从而为计算机技术在题库建设中的应用作了新的探讨。

膜厚度和流动状况对渗透蒸发过程的浓差极化影响

浓差极化对渗透蒸发过程的渗透速率和分离因子有一定负面影响。文中利用渗透蒸发过程中的分步阻力传质模型分析浓差极化,以含乙醇质量分数2%的乙醇/水为进料体系,观察进料流速对渗透蒸发过程中分离因子和通量的影响。分别估算了边界层阻力和膜阻力以及流速对边界层阻力的影响,并考察了膜厚度对浓差极化和分离因子的影响。

陆上盐丘区叠前深度偏移建模技术

针对陆上复杂盐丘区的地震、地质特点,将叠前深度偏移的速度建模分为盐上沉积层建模、盐间沉积层建模、盐顶建模、盐底建模、盐下沉积层建模五步,形成了一系列针对性很强的配套处理技术,主要包括:①面向叠前深度偏移的叠前道集配套处理;②时间域速度谱上异常时空调查;③借助于叠前时间偏移提高盐丘两翼的刻画精度;④叠前深度偏移迭代中CIP道集对盐丘顶、底刻画的约束;⑤地质、测井、钻井等信息对深度—速度模型迭代的约束。利用针对不同目标体的分步建模技术,建立了陆上A区盐丘区的符合实际地质构造的速度模型,实现了对盐丘侧翼的准确偏移归位,较好地消除了盐丘对下伏地层的影响,实现了盐下目的层合理、准确的成像。

Relationship between Rice Planthopper Occurrence Area in China and Atmospheric Circulation Indices

[Objective] This study aimed to establish models based on atmospheric cir- culation indices for forecasting the area attacked by rice planthopper every year, and to provide guide for preventing and controlling planthopper damage. [Method] The data related to rice planthopper occurrence and atmospheric circulation were collected and analyzed with the method of stepwise regression to establish the prediction models. [Result] The factors significantly related to the area attacked by rice plan-thopper were selected. Two types of prediction models were established. One was for Sogatella furcifera （Horvath）, based on Atlantic-Europe circulation pattern W in October in that year, Pacific polar vortex area index in October in that year, North America subtropical high index in August in that year, Atlantic-Europe circulation pattern W in June in that year, northern boundary of North America subtropical high in February in that year, Atlantic-Europe polar vortex intensity index in October in that year and Asia polar vortex intensity index in November in the last year; the other type of prediction models were for Nilaparvata lugens （Stal）, based on the Eastern Pacific subtropical high intensity index in July in that year, northern hemi- sphere polar vortex area index in October in the last year, Asia polar vortex strength index in November in the last year, north boundary of North America-At- lantic subtropical high in September in that year, north boundary of North Africa-At- lantic-North America subtropical high in January in that year, sunspot in September of the last year and eastern Pacific subtropical high area index in September in that year. [Conclusion] With the stepwise regression, the forecasting equations of the rice planthopper occurrence established based on the atmospheric circulation indices could be used for actual forecast.

风险投资对战略性新兴产业创新影响分析——基于倾向匹配得分(PSM)

文章首先通过倾向匹配得分解决战略性新兴产业上市公司数据样本中反事实样本缺失和指标内生性问题,然后使用分布滞后模型对风投介入上市公司与战略性新兴产业上市公司创新产出的关系进行回归,发现风投介入对上市公司创新产出存在非线性影响,主要表现为介入的前几年与企业专利产出负相关,临近退出时与企业专利产出量显著正相关。

Data classification method based on network dynamics analysis and cloud model

In order to reduce amount of data storage and improve processing capacity of the system, this paper proposes a new classification method of data source by combining phase synchronization model in network clustering with cloud model. Firstly, taking data source as a complex network, after the topography of network is obtained, the cloud model of each node data is determined by fuzzy analytic hierarchy process （AHP）. Secondly, by calculating expectation, entropy and hyper entropy of the cloud model, comprehensive coupling strength is got and then it is regarded as the edge weight of topography. Finally, distribution curve is obtained by iterating the phase of each node by means of phase synchronization model. Thus classification of data source is completed. This method can not only provide convenience for storage, cleaning and compression of data, but also improve the efficiency of data analysis.

基于COM+体系结构的管理系统开发应用

介绍了分布式组件COM+的体系,介绍了当前三层应用模型的结构及其优势,并给出了一个实例来说明如何在windows平台上构建基于这一新的模型应用。

Distribution and Abundance of Pelagic Tunicates in the North Yellow Sea

In this paper, the distribution patterns and abundance of pelagic tunicates in the North Yellow Sea of China during the period 2006-2007 were analyzed. Zooplankton samples were obtained with vertical towing from bottom to surface using a WP2 plankton net(200 μm mesh size; mouth area: 0.25 m2). Five species belonging to two classes were identified: Oikopleura dioica, O. longicauda and Fritillaria borealis belonging to class Appendicularia; Salpa fusiformis and Doliolum denticulatum of class Thaliacea. O. dioica and O. longicauda were the dominant species, occurring in the samples of all four seasons, with different distribution patterns. Their maximum abundance were 1664.7 ind. m-3(spring) and 1031.7 ind. m-3(spring) respectively. Following Oikopleura spp. were D. denticulatum, which was found only in autumn with an average abundance of 149.6 ind. m-3, and S. fusiformis, which was detected all the year long except for autumn with low abundance(max. abundance 289.4 ind. m-3 in summer). Only a very small amount of F. borealis was detected in summer samples, with an average abundance of 2.7 ind. m-3. The relationship between tunicates abundances and the environmental factors was analyzed using the stepwise regression model for each species. The variation of appendicularian abundance showed a significant correlation with the surface water temperature and with the concentration of Chl-a. No relationship was found between tunicates abundance and salinity, likely due to the slight changes in surface salinity of the studied area during the four seasons. Salps abundance and that of doliolids were significantly correlated to bottom water temperature, indicating that these two species(S. fusiformis and D. denticulatum) migrate vertically in the water column. In particular D. denticulatum, known to be a warm water species, showed not only an important correlation with water temperature, but also a spatial distribution connected to the warm currents in the North Yellow Sea. The occurrence of D. denticulatum represents an interesting result never found in past research work. Water temperature, algal distribution and currents were the most relevant environmental factors influencing the tunicate abundance and distribution in the North Yellow Sea. Further research is needed in order to get more information on the ecology of these organisms and to better understand their role in the ecosystem including the oceanic food web.

Study on cogging force of permanent magnet linear synchronous motor

Presented the methods to obtain the cogging force of permanent magnet linear synchronous motors(PMLSMs), analyzed the characteristics of the cogging force, and provided a basis for reducing the effect of the cogging force. 2-dimensional finite element method(2D FEM) was used to solve the whole motor when its mover was at dif- ferent position, so that the relation was derived between the cogging force and the mover position. The analysis results show that the cogging force between the two ends of the primary iron-core and the secondary permanent magnets (PMs) is sinusoidal function of the mover position under certain conditions only. Two proposed methods, namely direct and indirect methods, are applied to calculate the cogging force between the primary iron-core teeth and the secondary PMs. The agreement of the two methods is validated.

Parameter Estimations of the TFR Model Under Exponential Distribution at a Normal Stress

The TFR（Tampered Failure Rate） model was proposed by Bhattacharyya and Soejoeti（1989） for step-stress accelerated life tests, On step-stress completely accelerated test occasions, the paper gives a method of estimating parameters under a normal stress.