一种基于H.264的自适应快速模式选择算法

提出了一种基于H.264的快速模式选择算法.该算法首先进行Skip模式的判断.如果Skip模式不适合当前宏块,则继续利用宏块的空间同质性和时间静态性进行其他帧间模式的筛选.然后根据帧间模式选择的结果判断是否继续进行帧内预测.算法设计过程中,充分考虑Quan-tize Parameter对模式选择的影响,从而可以适用于不同码率的环境.实验证明,该算法在高低码率下都能在保证图像质量的同时大幅度提升编码速度.     

Analytical determination of flow resistance characteristic for combination channel inside hydraulic manifold block

Computational fluid dynamics （CFD） was used in conjunction with BP neural network to study the flow resistance characteristic of the combination-channel inside hydraulic manifold block （HMB）. The input parameters of the combination-channel model were confirmed to have effect on the pressure-drop by the numerical method, and a BP neural network model was accordingly constructed to predict the channel pressure-drops. The flow resistance characteristic curves of various channels were achieved, and a performance parameter was given to evaluate the through-flow characteristic of the channel according to the curves. The predictions are in agreement with the numerical computation, indicating that the method can be utilized to accurately determine the flow characteristic of the combination channel with high efficiency.     

页岩纹层与破裂方式实验研究

页岩纹层发育,微观非均质性强,页岩破裂方式受多种因素控制。以川南地区X101井龙马溪组深层页岩为研究对象,利用岩芯、薄片、测井资料、X-射线衍射与CT扫描等手段,结合单轴压缩与常规三轴压缩实验,系统研究了页岩破裂方式与纹层产状、矿物组成的关系。结果表明,主压应力垂直纹层方向的单轴压缩岩样形成张拉劈裂破坏,产生80°左右的垂直缝;三轴压缩实验中,主压应力垂直于纹层的岩样形成剪切破坏,裂缝与纹层以45°～65°高角度斜交,主压应力与纹层45°斜交的岩样以沿纹层面的剪切滑移破坏为主,主压应力平行纹层的岩样产生共轭剪切破坏,两者形成的裂缝与纹层呈10°～45°低角度斜交。对于不同纹层倾角的岩样,杨氏模量均与石英含量呈显著正相关,与黏土矿物呈显著负相关的关系,抗压强度与石英、黏土矿物含量的相关性受不同纹层倾角的影响。硅质纹层发育单层厚度大将增强页岩力学性质。     

数学专业师范生素质的调查研究

师范生的教师专业素质培养直接影响着其将来从师的水平,对数学学院的师范生必备教师专业素质,如数学专业和数学教育知识、教学能力与技能、教学技术、教学观念及数学课程改革等方面,进行了的问卷调查,通过对调查数据的统计分析,显示数学学院师范生具备较好的专业基础知识和数学基本能力,而缺少实践知识和实践技能;能使用现代教学手段制作数学课件;对新数学课程改革有一定的认识,但对高中新课程选修模块的掌握情况不容乐观,对师范生的培养及教学改革提出了几点建议。     

Progress in bionic information processing techniques for an electronic nose based on olfactory models

As a novel bionic analytical technique, an electronic nose, inspired by the mechanism of the biological olfactory system and integrated with modern sensing technology, electronic technology and pattern recognition technology, has been widely used in many areas. Moreover, recent basic research findings in biological olfaction combined with computational neuroscience promote its development both in methodology and application. In this review, the basic information processing principle of biological olfaction and artificial olfaction are summarized and compared, and four olfactory models and their applications to electronic noses are presented. Finally, a chaotic olfactory neural network is detailed and the utilization of several biologically oriented learning rules and its spatiotemporal dynamic propties for electronic noses are discussed. The integration of various phenomena and their mechanisms for biological olfaction into an electronic nose context for information processing will not only make them more bionic, but also perform better than conventional methods. However, many problems still remain, which should be solved by further cooperation between theorists and engineers. Supported by the National Creative Research Groups Science Foundation of China (Grant No. 60421002) and National Basic Research Programme of China (Grant No. 2004CB720302)     

农业经济系统与水资源环境系统耦合协调关系研究——以湖南省为例

该文综合考虑农业经济—水资源环境复合关系,构建了由农业投入、产出、现代化以及水资源压力、状态、管理六个维度、19个指标组成的农业经济和水资源环境系统评价指标体系,并基于客观组合赋权法确定指标权重,采用耦合协调度和障碍度诊断模型识别两系统耦合协调程度及其主要影响因素.以湖南省为例,分析其2008-2019年农业经济和水资...     

Identification of AtSM34, a novel tonoplast intrinsic protein-interacting polypeptide expressed in response to osmotic stress in germinating seedlings

Aquaporins are implicated in a wide variety of plant physiological processes, although the mechanisms involved in their regulation are not fully understood. To gain further insight into the regulatory factors involved in this process, we used a yeast two-hybrid system to screen for potential binding partners to the Arabidopsis tonoplast intrinsic protein (TIP) AtTIP1;1. This was the first protein identified to be associated with high water permeability in vacuolar membranes from Arabidopsis thaliana. Using ...     

Long-chain alkenones in Hotong Qagan Nur Lake sediments and its paleoclimatic implications

The long-chain alkenones present in the shallow sediment of Hotong Qagan Nur Lake in China are reported. According to the similarity of compositions and distributions of the alkenones determined commonly in the sediment section to those of marine sediment, it is reasonably referred that the alkenones might also originate from Prymnesiophyceae. In addition, the parameter U37k of alkenone is in positive correlation to δ18O values of authigenic calcium and magnesium minerals. This indicates that the parameter U37k of long-chain alkenone is also available to indicate paleoclimate of high-salinity alkaline lake.     

H型钢多道次粗轧工艺过程的数值分析

为了分析现有型钢轧制工艺的合理性,必须综合考虑轧件的微观组织演化、轧制力等多方面因素.为此,文中提出了针对H型钢多道次轧制过程的综合数值分析流程,通过热模拟实验和金相观测,建立轧件材料的高温屈服应力模型及奥氏体再结晶预报模型,并构建基于网格重构的多道次仿真分析方法.对某11道次H型钢多道次粗轧过程的仿真计算表明:轧制力的计算结果和现场实测数据吻合较好,现有多道次粗轧工艺对轧件腹板的晶粒细化作用较为明显.     

基于动载荷模拟的半刚性沥青路面响应分析

提出了一种基于虚拟样机和有限元技术的半刚性沥青路面动载荷响应分析方法,可准确计算重型货车各轴的动载荷.分析动、静载荷共同作用下路面的应力、应变,有效预测路面疲劳寿命.依据车辆动力学原理,基于ADAMS平台构建重型货车一路面系统的多自由度虚拟样机模型,通过仿真得出第一轴右侧单轮和第三轴右侧双轮的动载荷变化规律;基于弹性层状体系理论建立半刚性沥青路面的3D黏弹性有限元模型,在考虑轮胎矩形印迹和动载荷动态性的基础上,分析和比较单、双轮载荷作用下的路面响应.研究结果表明,路面的疲劳破坏是动载荷引起的水平应力、横向应力和垂直应力共同作用的结果,水平应力的交变变化是破坏的主要因素;此外,重型货车的后轴双轮造成的路面疲劳断裂破坏为前轴单轮的3.96倍.