Combinatorial model of solute transport in porous media

Modeling of solute transport is a key issue in the area of soil physics and hydrogeology. The most common approach (the convection-dispersion equation) considers an average convection flow rate and Fickian-like dispersion. Here,we propose a solute transport model in porous media of continuously expanding scale, according to the combinatorics principle. The model supposed actual porous media as a combinative body of many basic segments. First, we studied the solute transport process in each basic segment body, and then deduced the distribution of pore velocity in each basic segment body by difference approximation, finally assembled the solute transport process of each basic segment body into one of the combinative body. The simulation result coincided with the solute transport process observed in test. The model provides useful insight into the solute transport process of the non-Fickian dispersion in continuously expanding scale.     

承压含水层中反应性溶质运移实验与模拟研究——以苯胺和1,2-萘醌-4-磺酸钠为例

反应性溶质运移机理和模拟是地下水污染防治的前提和基础.为了考察化学反应和水流条件对溶质运移的影响,本文设计了承压含水层物理模型,以苯胺和1,2-萘醌-4-磺酸钠化学反应为例,开展了双分子化学反应条件下不同流速溶质运移实验和模拟研究,得到主要结论如下：（1）利用变系数二级反应率改进的ADRE模型能够较好地模拟在3种不同流速下双分子反应性溶质运移行为,峰值浓度相对误差分别为4.5％、5.0％及10.1％,模型可行,且模拟精度较高.（2）随着流速增大,模型参数m减小,而β0则增大.（3）模型对参数m值变化最敏感,其次是β0值,较不敏感的是弥散系数D.（4）随着流速增大,反应物和产物穿透曲线的不规则性加强,存在较明显的“拖尾”现象,今后需要进行机理方面的研究.     

高校数字媒体艺术专业动画教学创新与实践--以“乐高定格动画创意媒介实验课程”为例

近年来,高校数字媒体艺术专业大量开设,专业的建设亟须教学实践跟进。数字媒体艺术内容与形式并重,与动画有着千丝万缕的联系,特别是,相当一部分动画专业转型数字媒体艺术专业,基础课程教学要根据专业方向及时调整。基于这一现实,本文以动画基础教学为例,探讨数字媒体艺术语境下动画类课程的改革,并通过相应的课程实践,验证了保留动画创作相关课程优良教学基础的重要性,以及不断发展和扩充其教学内容和手段的必要性。数字媒体艺术专业课程建设要保持开放的态度和开阔的行业视野,让课堂与高速发展的技术和传播环境紧密接轨。     

A New Fast Algorithm for Computing 2─DDiscrete Cosine Transform

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Enhancement of ion transport in porous media by the use of a continuously reoriented electric field

Electromigration in porous media is enhanced by a new type of electrokinetic processing. Compared with a single-oriented electric field, a continuously reoriented electric field was proven to sharply enhance mass transport of several heavy metals in kaolin. The initial concentration of the metals was: Cd: 250 mg/kg; Cu: 250 mg/kg; Ni: 250 mg/kg; Zn: 900 mg/kg. Electric field reorientation was obtained by the use of a fixed anode and a cathode that rotated at different frequencies (0, 0.25, 1.00, 1.25, 2.00, 5.00 and 10.00 r/m). Mass transport evidently increased from 0 r/m to 1.25 r/m, and then decreased as the rotation speed reached 10 r/m. From 0 r/m to 1.25 r/m, mass transport increased 2.87 times for Cd, 3.17 times for Cu, 2.11 times for Ni, and 4.13 times for Zn. We suggest that continuous reorientation of the electric field facilitates the advance of ions through kaolin pores, minimizing the retardation effect caused by media tortuosity.     

浅析现代企业集团财务集中管控的必要性

我国社会主义市场经济不断发展,新的情况不断出现,过去集团公司各分公司延用的财务分散管理造成了许多不利于集团管理的弊端,财务集中管控弥补了分散管理的不足,是现代企业集团公司治理模式。     

Influence of water saturation on propagation of elastic waves in transversely isotropic nearly saturated soil

Biot's two-phase theory for fluid-saturated porous media was applied in a study carried out to investigate the influence of water saturation on propagation of elastic wave in transversely isotropic nearly saturated soil. The characteristic equations for wave propagation were derived and solved analytically. The results showed that there are four waves: the first and second quasi-longitudinal waves (QP1 and QP2), the quasi-transverse wave (QSV) and the anti-plane transverse wave (SH). Numerical results are given to illustrate the influence of saturation on the velocity, dispersion and attenuation of the four body waves. Some typical numerical results are discussed and plotted. The results can be meaningful for soil dynamics and earthquake engineering.     

坚持“七字”方针 提高教学质量

教学管理是学校管理的核心环节。教学质量的提高是通过不断强化教学过程管理来实现的。近几年来,我校通过强化教学过程管理,从每一个教学环节抓起,促使教学质量不断提高。     

Influence of water saturation on propagation of elastic waves in transversely isotropic nearly saturated soil

INTRODUCTIONIthaslongbeenrecognizedthatcompression alwavespropagationinsaturatedsoilsisstronglyaffectedbythewaterfillingtheintersticesofthesoilgrains.HardinandRichart(1 963 )appliedthetwo phasetheoryofBiot(1 956)andstudiedtheinfluenceoftheconfiningpressur…     

信息化时代下幼儿教师媒体素养研究

信息化时代新媒体不断涌现,媒体素养已成为信息时代的一种基本素养。教育改革中新媒体日益融入课堂的教学,以提高教与学的绩效。幼儿的媒介素养如何全面培养,有效引导使用媒体,对幼儿教师专业化发展提出新的要求。为此,当代幼儿教师必须具备良好的媒体素养,恰切的选择、使用和整合媒体与教学内容,优化教学,培养幼儿学习者的全面发展,进而推动教育信息化和教育均衡化发展。     

Why do elephants have big ear flaps?

In this essay we shall try to answer the question in the title with some geometry and heat transfer thrown in for effect. For doing so, as the joke goes, allow me to assume the elephant as a sphere. The reason will be apparent soon. Arunn Narasimhan is a faculty at the Indian Institute of Technology Madras. His research interests include transport in porous media, phase change materials and heat transfer in biological systems.     

研究生全英文专业课程教学实践及改革探索——以Neutron Technology and Its Application为例

针对不同教育背景的外国留学生研究生和本国研究生的全英文授课问题,借鉴国际先进的教学理念和教学方法,以Neutron Technology and Its Application课程为例,采用互动式教学模式不断增强学生的英语学术交流水平,拓展其知识面,同时考虑到研究生自身的研究方向,引导其结合本课程的主要内容,增强解决实际问题的能力。     

一种自发形成的非平衡有序结构及其可用性探索

论证了在汽液界面也存在一种自发形成的非平衡有序结构,此结构由分子因热运动而在汽液两相之间迁移而自发形成.针对该有序结构提出了一个实验模型,该模型中每个自发过程都会使某环节向平衡靠近而却同时导致另一环节偏离平衡,自发过程之间的联动和互补作用形成一个自持续的循环机制.分析表明,通过适当的动力学机制可使汽液界面的相变过程总是保持不平衡,从液相净迁移进汽相的分子能以设定的路径返回液面并在此过程中释放分子势能做功.提出与麦克斯韦妖功能类似的非耗能有序化自组织机制是可能存在的,分子的微观无序运动能转化为宏观的定向运动.     

中国近代新闻史研究三题

中国近代新闻史研究既要注重史料的考释,又要侧重学理的阐述。就目前而言,研究范围的界定与研究视野的拓展并不矛盾;探究报刊等传媒与中国近代文化转型的关系是中国近代新闻史教学与研究的焦点;中国近代新闻史研究既要有宏观视野,又要从微观层面来考察。     

高等职业教育人才培养模式探讨

近年来我国高等职业教育发展迅速,规模不断扩大,但受到普通高等教育的影响,目前还存在着一些亟待解决的问题。针对症结所在,新世纪高等职业教育人才培养模式的建构应从分析高等职业教育培养的人才层次和规格要求入手,以技术型人才培养为目标,以产学结合为特色,强化课程整合,走内涵发展之路。     

传媒生产关系研究

传媒产品是由传媒劳动者以一定的方式结合起来共同活动而生产出来的,传媒生产关系客观存在。传媒生产关系同物质生产关系是对立统一的两个方面。传媒生产关系的总和构成上层建筑,物质生产关系的总和构成经济基础。生产资料的所有制形式不仅是物质生产关系的基础,而且也是传媒生产关系的基础。改善传媒生产关系,有利于传媒生产力和传媒经济的发展。     

后现代消费社会身体的转向与去向

后现代消费社会身体的文化与符号学意义已发生了显著的变化。哲学界意识与身体的“二元论”过渡到“一元论”;消费文化在形成过程中,传媒中充斥着各种大写的身体形象。然而,现代人应找寻真正的身与心的自由,这种自由既不是在肉体欲望中驻足,也不是要回归纯粹的理性,而需要在肉体与灵魂中找到一个中间点,从而获得真正的完美人性。     

调整学校布局 推进农牧区基础教育均衡发展

青海省农牧区教育存在着规模小、成本高、效益低、质量差等问题。改革开放以来,青海省不断进行学校布局调整,适当集中、扩大规模,走以内涵发展为主的路子。其学校布局调整的基本思路为,明确布局调整的指导思想;理清布局调整的总体思路;科学量化寄宿制中小学的标准;实施布局调整的具体要求。今后学校布局调整中还需要注意避免对教学点一刀切;处理好资源归属与管理问题;注重亲情教育问题研究;探索学校管理新模式等。     

教育传播学视野下的教务管理信息化构建探析

随着我国高等教育进入大众化阶段,高校不断进行扩招,教务管理过程中急需对＂海量＂教育管理信息进行采集、存储、传播和反馈,文章试从教育传播学角度研究教务管理信息化,通过教育传播学理论、教务管理业务流程的介绍,分析教务管理传播主体、传播媒体和通道、反馈、有效交流等几个方面的问题,提出教育传播学对教务管理研究的重要意义和有效传播的策略。     

Tracking multiple people under occlusion and across cameras using probabilistic models

Tracking multiple people under occlusion and across cameras is a challenging question for discussion. Furthermore, the cameras in this study are used to extend the field of view, which are distinguished from the same field of view. Such corre-spondence between multiple cameras is a burgeoning research subject in the area of computer vision. This paper effectively solves the problems of tracking multiple people who pass from one camera to another and segmenting people under occlusion using probabilistic models. The probabilistic models are composed ofblob model, motion model and color model, which make the most of the space, motion and color information. First, we present a color model that uses maximum likelihood estimation based on non-parametric kernel density estimation. Second, we introduce a blob model based on mean shift, which segments the body into many regions according to the color of each person in order to spatially localize the color features corresponding to the way people are dressed. Clothes can be any mixture of colors. Third, we bring forward a motion model based on statistical probability which indicates the movement position of the same person between two successive frames in a single camera. Finally, we effectively unify the three models into a general probabilistic model and attain a maximization likelihood probability image, which is used to segment the foreground region under occlusion and to match people across multiple cameras.