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In general, the design work with traditional measures is done by hand, which cannot meet the needs of the technology and manufacture. So the author has developed a CAD hydraulic design software fit for lower specific speed axial flow runner, which is easily operated by users.The main research work of this paper is as follows:1 Analyzing the main reason of axial flow power station cannot work well under littler volume of flow in some season and putting forward an improving scheme, pointing out the characters of design under abnormal factors.2 Combined with the development of the industry in our country, the abnormal hydraulic design method of propeller turbine is discussed based on present literature, data and experiment results.3 Guided by the design method of software engineering, a suit of hydraulic design software of Lower Specific Speed Axial Flow Runner is programmed by the object-oriented programming language Visual Basic and a straightforward, concise and standard Windows human-computer dialogue interface is designed for the system, which makes the operation of the system very convenient.4 ActiveX Automation technology is adopted as the interface with AutoCAD and the hydraulic drawings are edited, modified by AutoCAD until hydraulic model drawings according with the demand of engineering practice are output.5 To resolve practice problem, the author has designed a lower specific speed axial flow runner for Duowa Power Station through an example.
论文的主要内容有:1 深入分析很多轴流定桨式水电站枯水季节小流量下不能发电的主要原因,提出减容改造方案,并指出超常规条件下的改造设计特点。2 结合国情及行业发展需要,参考现有资料、文献和前人的研究成果,进行低比转速轴流式转轮叶片水力设计方法的研究,对轴流式转轮叶片的奇点分布法水力设计进行了全面的探索,结合现代计算机技术,找到了一种针对特殊条件的轴流式转轮叶片水力设计方法。3 仔细比较多种AutoCAD二次开发工具后,结合本课题的特点,选用Visual Basic语言,综合应用软件工程的设计思想,进行低比转速轴流式转轮叶片水力设计软件的编制,为系统设计了直观、简洁和标准的Windows人机对话界面,便于用户操作;编程时在考虑到设计条件特殊性的同时,尽量做到程序的通用性,使之可用于解决同一类问题;另外,大部分程序还可移植到普通轴流式转轮叶片水力设计中,具有良好的适应性。4 利用ActiveX Automation技术与AutoCAD接口,对AutoCAD进行二次开发,在AutoCAD下实现水力图的自动生成和编辑,直至输出符合实际工程要求的木模图。5 通过算例,为多哇水电站设计了一个低比转速轴流定桨式转轮,解决其在枯水期小流量下不能发电的问题。
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The proposed approach is verified by two cantilever beam experiments under ideal boundary conditions and uncertain end conditions, and the approach presented here is suitable for crack identification in engineering even if small frequency measuring errors exist.
对于理想边界条件下的裂纹参数识别,在测量频率存在小误差情况下,该方法仍能给出比较满意的结果,对于非完全固支边界条件下的裂纹参数识别,利用本文方法能得到比Narkis的方法更精确的裂纹位置识别结果。
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The carriage stopped, as I had expected, at the hotel door; my flame (that is the very word for an opera inamorata) alighted: though muffled in a cloak — an unnecessary encumbrance, by the by, on so warm a June evening — I knew her instantly by her little foot, seen peeping from the skirt of her dress, as she skipped from the carriage step.
不出我所料,马车在房门口停了下来。我的情人(这两个字恰好用来形容一个唱歌剧的情人)从车上走下,尽管罩着斗篷——顺便说一句,那么暖和的六月夜晚,这完全是多此一举。——她从马车踏步上跳下来时,我从那双露在裙子下的小脚,立刻认出了她来。
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The numerical results show that, surface temperature gradient in the pool heated from inner wall is 10% higher than that heated from outer wall with a fixed temperature difference between the outer and inner walls. Meanwhile, the critical Marangoni number for the incipience of hydrothermal wave (Ma_{c}=3.06\times 10^{5}) in the pool heated from inner wall is smaller than that (Ma_{c}=3.34\times 10^{5}) heated from outer wall.
发现在内外壁间温差相同的情况下,在内壁加热的液层里,流体表面的温度梯度高于外壁加热情况下10%左右;相应地,发生热流体波的临界Marangoni 数Ma_{c}=3.06\times 10^{5}(或临界温差\Delta T_{c}=4.58K)低于外壁加热情况下的Ma_{c}=3.34\times 10^{5}(或\Delta T_{c}=5.0K)。
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ABSTRACT Aiming at problems of trans-vector controller in a vehicle-carried induction motor such as variable rotor and stator resistance following motor temperature, and their inductance varying with flux saturation degrees. Firstly, CSI and VSI are introduced, for CSI, it can hold the advantages both FOC and DTC using stator flux directional, PI parameter and simulation are also introduced. Secondly, equations of IM in the synchronous rotary frame and its static counterpart, as figuring in the saturation condition of magnetic field, are dealt in this paper and the simulation results are presented. Thereafter, the parameter designing of PI trans-vector controller is processed, which features the non-linear model. In practical realization, as neglecting the dynamical change of motor inductance, this paper employs online modification of inductance parameters, according to the flux saturation, then transforms the non-linear equations into linear ones, and so compacts the structure of controller. Thirdly, in view of the maximum torque output is extraordinary requisite when Electrical Vehicle start up, accelerate, and overtake, this paper issues the maximum torque when both inverter and battery capacity is corporeally definite. Fourthly, on-line differentiating and analyzing both rotor's time constants and its flux by using the expanding order reduction and discrete Kalman filter equation are fathomed, in order to realize high-performance trans-vector algorithm, and also the simulation results are presented. Fifthly, the close-loop regenerative brake system, when the EV's torque is set constant, is deduced; at the same time, unification of electric drive model and brake model is executed. Combined with maximum charge current demands, the mathematical model for online yielding torque as a demand.
本论文针对车载异步电机在矢量控制器所遇到的问题:定转子电阻随温度变化及随电机饱和程度变化的转子电感及定子电感而影响电机调速性能提出一套完整的解决方案:分析了电流型逆变器和电压型逆变器在实现矢量控制时控制器参数的计算,分析出对于电流型逆变器在采用定子磁场定向时,其性能同时具有矢量控制和直接转矩控制两者的优势,并对电压型逆变器在转子磁场定向下的模型进行了仿真研究;建立异步电机非线性模型,推导出考虑磁饱和时异步电机在同步旋转坐标系及静止坐标系下的方程,并做出了仿真结果,建立异步电机在非线性模型下的矢量控制调节器的PI参数设计,在实际应用中,若忽略电机电感的动态变化,可以根据当前的磁路饱和状态而在线修正电感参数,从而将非线性方程线性化,降低控制器的复杂度;考虑到电动汽车在起动和加速超车时需要电机有最大转矩输出,本文讨论在逆变器容量一定和电池供电能力有限的情况下电机最大转矩输出问题;推导了异步电机扩展降阶、离散卡尔曼滤波方程在线辨识转子时间常数和转子磁通,用于实现高性能的矢量控制算法,并给出了仿真结果;推导出了电动汽车恒转矩给定的闭环回馈制动系统,实现了电动控制模型和制动模型的统一,而且结合铅酸电池最大充电电流的要求,为制动转矩在线给定建立了数学模型;设计了基于双DSP系统的高性能矢量控制器软硬件框图,并以大量实验数据说明矢量控制在电动汽车应用的实际应用状况。
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Comparison with the results in the inertial frame shows that the same rate of change of the mean atomic energy can be obtained in these two different frames only when we assume a thermal bath at the Unruh temperature in the coaccelerated frame.
与惯性框架下的结果相比较,我们证明了要使这两个不同的框架下原子的平均能量变化率一致的话,我们就必须假定在共同加速的框架下存在一个Unruh温度的热库。
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Studied the inner resistance in different charge capacity and different charge magnification, researched the charge efficiency in different charge capacity, and measured the inner resistance at high rate.
通过对失效电池不同充电容量、充电倍率下交流内阻的研究和大电流脉冲下直流内阻的研究,确定了快速判定MH-Ni电池是否失效的相关方法,并通过测量电池的内压和不同充电容量下的充电效率讨论了其有效性
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Main contents and conclusions are: 1 The ionization current was measured continuously by a charge-integration method with a computer after the introduction of radon into the chamber.
主要内容及结论:1充氡后利用计算机连续进行电离电流累积测量,得到了精细的电流随时间的变化曲线,可清楚看出氡及其子体的生成衰变造成的电离电流的生长—稳定—衰减过程,与理论计算值进行了比较,由电离电流衰减速度的变化得出氡吸附作用的影响,并测量到电离室冲洗后氡的反扩散现象;2由已知活度的标准源定出相对测量的刻度系数K值,K=24.62 Bq/pA,对同一个监测源以半年为周期进行多次测量后得出稳定性符合要求;3通过测量电离电流和气压的关系曲线以及不同气压下的饱和曲线,确定了常规的工作条件;4测量了盐酸清洗电离室内表面降低本底的效果;5不确定度分析表明相对测氡的扩展不确定度(k=2)小于5%,由本底涨落得出探测下限为0.5 Bq;6理论上对壁损失修正进行了计算,实验上保持电离室工作在饱和区的情况下,测量了不同气压下电离电流的变化,从中得出了壁损失随气压变化的规律,可以看出,电离电流的实测值和计算值随气压变化规律基本一致;当气压大于125 kPa时,端效应等其它因素造成的影响不大于2%,因而在此工作条件下,测量电离电流后通过计算修正壁损失可以实现近似的绝对测氡,提出了进一步提高绝对测量准确度的方法。
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The annealing velocity for 100 ℃ is higher than that for 25 ℃ at the same irradiation dose. The annealing degree of isochronal annealing is close to that of isothermal annealing at 100 ℃ for 168 h.
经相同总剂量辐照的器件,高温100 ℃下的退火速度远大于室温25 ℃下的退火速度。25~250 ℃下的等时退火,其退火程度接近168 h的100 ℃等温退火。
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The keyboard by pressing a button can not be up after the fault diagnosis method: press the keyboard after a key can not bounce as a result of a number of keyboard, under the keycap spring elastic weakening of aging, caused by the spring deformation, resulting in the contact can not be separated in time and thus can not bounce.
键盘的某个按键按下后无法弹起的故障诊断方法:键盘的某个键按下后无法弹起是由于一些键盘、键帽下的弹簧老化使弹力减弱,引起弹簧变形,导致该触点不能及时分离,从而无法弹起。
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And discuss some key point of integrated management system design, include hazard identification and risk assessment and risk control in the occupational health and safety management, the measure of satisfaction target of customer, the flawlessness of law system, the integration of the integrated management system and enterprise standardization system, unify lead institution and work orgnization, integreted internal audit and integrated management review.
同时,论述了一体化管理体系构建中的几个主要问题,包括职业健康安全管理中的危险源辨识、风险评价和风险控制、顾客满意度的科学监测、法律、法规体系的完善、一体化管理体系与企业标准化体系的有机结合、统一的领导机构和工作机构、一体化的内部审核和管理评审。
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Deepwater Taranaki is investigated for its petroleum potential, using all available seismic data tied to shallow-water wells.
运用与浅水井相关的现有全部震波探测数据考察了深海区塔拉纳基盆地的油藏前景。
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If you're huffing and puffing at any point during the run, slow down and make sure you can take deep breathes.
如果你任何时候在跑步过程中气喘如牛,降低速度并且确保你能够深呼吸。