Banach代数中鞅变换的若干收敛性

主要讨论了Banach代数中鞅变换的收敛性,指出在一类条件下,鞅变换是依范数收敛及几乎处处收敛的.     

高精度步距规在检验数控机床时的突出优势

介绍高精度步距规的特点及其检验数控机床的优势,提出相关建议。     

“四步法”教学模式在分子生物学实验课程中的探究

采用"四步法"教学模式把分子生物学实验的教学内容划分为"学会—引导—独立—综合或设计"四个层次进行教学,循序渐进地对学生进行培养,让学生先"学会"、进而"会学"、再而"能创"。通过三年的教学实践证明:"四步法"教学模式在分子生物学实验教学中能较好地培养学生在分子生物学实验方面的基本技能,该方法还能有效地提高学生的创造性思维。     

以支撑脚为参考系的轮滑双蹬技术外刃蹬地动作力学分析

探究轮滑运动双蹬技术的外刃蹬地动作是否提高了运动员在前进方向上的速度,运用力学知识对运动员在外刃蹬地时的受力情况、步长、做功、速度和动能的变化进行分析。结果:在假设各种阻力为零的条件下,以支撑脚为参考系,运动员外刃蹬地时身体重心在支撑反作用力的水平分力方向上位移为零,在支撑反作用力水平分力作用的方向上身体重心的速度为零,支撑反作用力的水平分力所做的功为零,身体重心在支撑腿滑进方向上的速度大小没有变化,动能没有增加。结论:在假设各种阻力为零的条件下,以支撑脚为参考系,运动员外刃蹬地时身体重心的合速度没有增大,动能没有增加。     

Validity of Palpation Recovery Pulse Rate to Estimate Exercise Heart Rate Following Four Intensities of Bench Step Exercise

Abstract

Previous investigations regarding activity during the post-knowledge of results (KR) interval have considered the performance of interference groups over KR-supplied acquisition trials as indicative of effects upon learning. The absence of transfer tests in these studies, however, preclude such an assumption. Indeed, the use of a retention test in the present investigation (no-KR trials following an interpolated phase) provided evidence suggesting that, while activity during the post-KR interval is detrimental to performance, no such assumption can be made regarding this effect upon learning. These findings are discussed relative to recent arguments that some of the commonly accepted “Laws of KR” may be contradictory when applied simultaneously to motor learning and performance.     

Enhanced control of DFIG-used back-to-back PWM VSC under unbalanced grid voltage conditions

This paper presents a unified positive-and negative-sequence dual-dq dynamic model of wind-turbine driven doubly-fed induction generator(DFIG) under unbalanced grid voltage conditions. Strategies for enhanced control and operation of a DFIG-used back-to-back(BTB) PWM voltage source converter(VSC) are proposed. The modified control design for the grid-side converter in the stationary αβ frames diminishes the amplitude of DC-link voltage ripples of twice the grid frequency,and the two proposed control targets for the rotor-side converter are alternatively achieved,which,as a result,improve the fault-ride through(FRT) capability of the DFIG based wind power generation systems during unbalanced network supply. A complete unbalanced control scheme with both grid-and rotor-side converters included is designed. Finally,simulation was carried out on a 1.5 MW wind-turbine driven DFIG system and the validity of the developed unified model and the feasibility of the proposed control strategies are all confirmed by the simulated results.     

略论"三个代表"思想蕴涵的辩证唯物主义及历史唯物主义思想

江泽民同志提出的“三个代表”重要思想与马克思列宁主义、毛泽东思想和邓小平理论一脉相承。正确理解和把握其运涵的哲学思想,是新时期进一步贯彻“三个代表”思想精神,永葆中国共产党的先进地位的哲学基础和力量源泉。     

线性同余随机数列二维结构的快速算法

在给出线性同余(LCG)随机数列平行直线族精确表达式的基础上，证明计算LCG最少平行线条数和谱检验法，都为对分数A／M的渐近分数及其相邻渐近分数插值的比较，并提出LCG二维结构的快速算法。     

乌鲁木齐市城乡交错带土地利用与景观格局变化研究

文章运用城市地理学、景观生态学有关原理和方法,从土地利用类型入手,以乌鲁木齐城乡交错带内四个乡为着眼点,依据调查资料和实地考察从较微观层面上解析了乌鲁木齐城乡交错带土地利用变化特征,并对不同时段的土地景观格局进行了对比分析,从而得出了一些相关结论。     

钢琴教学应遵循的几个原则

钢琴教学是复杂多变的,教师只有在全面深入了解学生的情况之后才能实施有效的教法,否则,难以达到良好的教学效果,教师的责任就是从学生的实际出发对学生进行系统的艺术、技术的训练,引导学生掌握正确的演奏方法,培养、提高学生的音乐审美和鉴赏能力。