从信息论角度看视频图像压缩编码技术的发展

随着视频通信技术的发展,视频图像压缩编码也成为人们关注的热点问题。从信息论的角度分析视频图像压缩编码技术在发展过程中如何减少冗余度以及获得高质量的图像画面的问题,并详细介绍了MPEG-4的编码方法。     

运用微元法推导平面曲线弧长公式

改革《数学分析》教材中关于推导平面曲线弧长公式的传统方法和顺序,具体论述运用微元法先推导平面曲线弧长的直角坐标公式,再推导其参数公式,后推导其极坐标公式的创新方法及技巧。     

基于NI ELVIS Ⅱ+的信号处理技术虚拟仿真开放式实验教学探析

近几年,国家重点研发科技方向之一为海洋领域,目前水声工程领域的各科研单位亟须从事水声信号处理技术的研究型人才。针对这一需求,水声工程专业研究生课程教学改革必须体现"基础理论、分析方法和工程实践技术并重"的理念。在研究生一年级的课堂教学环节中,研究生可以灵活进入国家级开放式水声教学实验中心,通过调试NI ELVIS Ⅱ +信号处理实验箱,完成水声信号处理基础案例设计。这不仅可以开阔研究生的工程实践能力视野,也为研究生的毕业设计和未来从事科研工作建立一定的水声信号处理技术储备。     

Virtual local target method for avoiding local minimum in potential field based robot navigation

A novel robot navigation algorithm with global path generation capability is presented. Local minimum is a most intractable but is an encountered frequently problem in potential field based robot navigation. Through appointing appropriately some virtual local targets on the journey, it can be solved effectively. The key concept employed in this algorithm are the rules that govern when and how to appoint these virtual local targets. When the robot finds itself in danger of local minimum, a virtual local target is appointed to replace the global goal temporarily according to the rules. After the virtual target is reached, the robot continues on its journey by heading towards the global goal. The algorithm prevents the robot from running into local minima anymore. Simulation results showed that it is very effective in complex obstacle environments. Project (No. 69904009) supported by the National Natural Science Foundation of China     

论晚唐的牛李党争

牛李党争是晚唐历史上的重大事件,对当时社会生活的各个方面都有重大影响。传统认为,党争的焦点是对进士科的态度,牛党重进士科,李党重门第,李党是反动的,牛党是进步的,因此,关于两党的评价是偏牛非李。笔者认为,传统观点有失偏颇,本文就牛李党争的焦点,两党的社会基础以及评价作一探讨。     

论高校教学设备采购适应市场经济规律的管理体制

在改革开放的当今社会中，经济体制和计划供应体制都在进行着改革，这种改革的方向是：原来的计划经济转轨为市场经济，原来的计划供应转轨为市场竞争采购。新形势下，高校教学设备采购模式千变万化，为了适应社会变革的需要，建立合理的设备采购管理模式，已势在必行。     

桑叶的化学成分、药理活性及应用研究进展

目的：为合理开发利用桑叶资源提供依据。方法：采取查阅文献资料及实地考察相结合的方法。结果：桑叶中含N－糖化合物，芸香甙、，槲皮素，挥发油，氨基酸，维生素及微量元素等多种活化学成分，具有降血糖，降血脂，降血压，抗菌和抗病毒多种药理活性，结果：桑叶资源丰富，在药品和功能性食品领域研究开发前景广阔。     

激发学生学习兴趣搞好初中语文教学

在语文教学中,提高学生的学习兴趣对于增强教学效果十分关键.只有充分激发学生的学习兴趣,才能使学生轻松地克服学习中遇到的困难,自然地由被动接受知识变成主动学习,把艰苦的学习看成快乐的享受.     

Phenolic compounds participating in mulberry juice sediment formation during storage

The stability of clarified juice is of great importance in the beverage industry and to consumers. Phenolic compounds are considered to be one of the main factors responsible for sediment formation. The aim of this study is to investigate the changes in the phenolic content in clarified mulberry juice during storage. Hence, separation, identification, quantification, and analysis of the changes in the contents of phenolic compounds, both free and bound forms, in the supernatant and sediments of mulberry juice, were carried out using high performance liquid chromatographic system, equipped with a photo-diode array detector (HPLC-PDA) and HPLC coupled with quadrupole-time of flight mass spectrometric (HPLC-QTOF-MS/MS) techniques. There was an increase in the amount of sediment formed over the period of study. Total phenolic content of supernatant, as well as free phenolic content in the extracts of the precipitate decreased, whereas the bound phenolic content in the sediment increased. Quantitative estimation of individual phenolic compounds indicated high degradation of free anthocyanins in the supernatant and sediment from 938.60 to 2.30 mg/L and 235.60 to 1.74 mg/g, respectively. A decrease in flavonoids in the supernatant was also observed, whereas the contents of bound forms of gallic acid, protocatechuic acid, caffeic acid, and rutin in the sediment increased. Anthocyanins were the most abundant form of phenolics in the sediment, and accounted for 67.2% of total phenolics after 8 weeks of storage. These results revealed that phenolic compounds, particularly anthocyanins, were involved in the formation of sediments in mulberry juice during storage.     

正确处理CAI与传统教学的关系

CAI作为一种新兴的教学手段,在职业学校的技术课中发挥着越来越重要的作用,如何正确处理CAI与传统教学的关系,使之发挥最佳教学效果,笔者根据自己的教学经验,谈了对这个问题的看法。