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Studied present measuring methods" advantages and disadvantages, and presented the necessity and importance of researching propellant transient heat transfer.2.according to 130 and aeronautic 90 rocket projectiles" structure, analysed and acquired physical and mathematical models for propellant transient heat transfer, also designed propellant temperature field simulation units for test.3.acquired discrete transient heat balance equation and temperature calculation program, and gave contrasting curves between experimental temperature values and program calculating temperature values as well as maximum errors and average square root errors between them.4.by programs based on the first class boundary condition, worked out temperature distribution in propellant temperature field simulation units at different time, analysed temperature field distribution law and main elements affecting heat transfer, acquired propellant mass weighted average temperature and one at the half position of propellant maximum thickness as well as maximum errors and average square root errors between them.5.established transient heat transfer mathematical model and temperature calculation program for the third class boundary condition, drew contrasting curves between temperature experimental values and calculation values and gave maximum errors and average square root errors between them, got temperature distribution in the simulation unit at different time and main elements affecting heat conduction, figured out propellant mass weighted average temperature and one at the half position of propellant maximum thickness as well as maximum errors and average square root errors between them.
分析了现有测试方法的优缺点,提出了研究推进剂瞬态导热的必要性和重要性。 2。根据130和航90两种火箭弹的结构,分析得到了推进剂传热的物理模型和数学模型,设计了推进剂温度场模拟实验装置。 3。得到了离散形式的瞬态热平衡方程和温度场计算程序,给出了实验温度与程序计算温度值的对比曲线及其最大偏差与均方差。 4。利用程序求出了第一类边界条件下、不同时刻推进剂温度场模拟装置中的温度分布,分析了温度场的分布规律和影响传热的主要因素,求出了推进剂质量加权平均温度和最大肉厚1/2处的温度时间曲线并给出了两者之间的最大偏差与均方差。 5。建立了第三类边界条件下的瞬态导热数学模型和温度计算程序,求出了温度实测值与计算值的对比曲线并给出了两者之间的最大偏差与均方差,得到了不同时刻温度场模拟装置的温度分布与影响导热的主要因素,求出了推进剂质量加权平均温度和最大肉厚1/2处温度及两者之间的最大偏差与均方差,讨论并确定了能代表130和航90推进剂温度的特征点的位置。
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The best results were obtained with 40 mg cellulose/2.5 mL water at 380 ℃ and 16 s, affording oligosaccharide recovery above 29%, or 80 mg cellulose/2.5 mL water at 380 ℃ and 18 s, affording hexose recovery above 39%.
最优水解条件研究显示,在380 ℃, 40 mg纤维素/2.5 mL水条件下反应16 s可获得最大的低聚糖产率,为29.3%,在380 ℃, 80 mg纤维素/2.5 mL水条件下反应18 s可获得最大的六碳糖产率,为39.2%。
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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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B Of the six basic media MS, MS1/2 (half-strength of MS salts and vitamins), WPM, DKW, B5 and SH, MS1/2 was the most proper one to induce somatic embryos. Somatic embryos generally regenerated directly from excised zygotic cotyledons. PGRs combination affected somatic embryogenesis significantly. Medium with NAA 1mg/L, TDZ 0.05mg/L, IBA 2—10mg/L combined with BA 10mg/L, or IBA 10mg/L integrated with BA 0-2mg/L gave the highest induction rate. Excised zygotic hypocotyls had the strongest potential to produce callus. Callus induction was also affected significantly by media and PGRs. The proper callus induction condition was MS1/2 medium containing NAA 1mg/L, IBA 10mg/L, BA 2-5mg/L and TDZ 0.05mg/L. Harvest period affect somatic embryogenesis significantly. Zygotic embryo explants collected from the end of July to the middle of August had strong potential to generate somatic embryos, when endosperm finished solidification, different parts of the embryos were completely formed, the size of embryos occupied about 2/3 of the embryo sac. Provided with optimized conditions, direct somatic embryogenesis rate can attain to 33. 68%, and callus induction rate of hypocotyls was up to 90.7%. Cytological observation on megasporogenesis and zygotic embryogenesis of Manchurian ash showed that the ovary was twicarpellum, twilocular with two ovules each loculus. The ovule was tenuinucellar and anatropous, with one megasporcocyte. The development of embryo sac is of the Polygoum type.
体细胞胚胎发生研究的结果表明:(1)成熟过程中的合子胚是诱导水曲柳体细胞胚胎发生的最佳外植体材料;(2)在所试验到的MS、MS1/2(将MS的所有成分均减半)、WPM、DKW、B〓、SH等六种基本培养基中,MS1/2是最适合诱导水曲柳体细胞胚胎发生的基本培养基;(3)水曲柳的体细胞胚胎发生以直接发生为主,体细胞胚主要来自于从合子胚分离的完整子叶;(4)培养基中的激素组合对水曲柳的体细胞胚胎发生有显著影响,诱导直接体细胞胚发生较好的激素组合有NAA 1mg/L+IBA 2,5,10mg/L+BA 10mg/L+TDZ 0.05mg/L和NAA 1mg/L+IBA 10mg/L+BA 0,2mg/L+TDZ 0.05mg/L;(5)合子胚分离的下胚轴具有最强的愈伤组织诱导潜力,少数愈伤组织可以分化出体细胞胚;(6)愈伤组织的诱导也受培养基和激素配比的显著影响,最适宜诱导的培养条件为MS1/2+NAA 1mg/L+IBA 10mg/L+BA 2,5mg/L+TDZ0.05mg/L;(7)采种时间对体细胞胚胎发生有显著影响。7月末到8月中旬的合子胚具有较强的体细胞胚发生潜力,此时种子尚未成熟,胚乳已呈固态,种胚的各个部分已分化完全,种胚体积占胚腔的大约2/3;(8)在各自综合的最适条件下,完整子叶的体细胞胚诱导率可达33.68%,下胚轴的愈伤组织诱导率可达90.7%。
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In chapter two, under non-Lipschitz condition, the existence and uniqueness of the solution of the second kind of BSDE is researched, based on it, the stability of the solution is proved; In chapter three, under non-Lipschitz condition, the comparison theorem of the solution of the second kind of BSDE is proved and using the monotone iterative technique , the existence of minimal and maximal solution is constructively proved; in chapter four, on the base of above results, we get some results of the second kind of BSDE which partly decouple with SDE, which include that the solution of the BSDE is continuous in the initial value of SDE and the application to optimal control and dynamic programming. At the end of this section, the character of the corresponding utility function has been discussed, e.g monotonicity, concavity and risk aversion; in chapter 5, for the first land of BSDE ,using the monotone iterative technique , the existence of minimal and maximal solution is proved and other characters and applications to utility function are studied.
首先,第二章在非Lipschitz条件下,研究了第二类方程的解的存在唯一性问题,在此基础上,又证明了解的稳定性;第三章在非Lipschitz条件下,证明了第二类BSDE解的比较定理,并在此基础上,利用单调迭代的方法,构造性证明了最大、最小解的存在性;第四章在以上的一些理论基础之上,得到了相应的与第二类倒向随机微分方程耦合的正倒向随机微分方程系统的一些结果,主要包括倒向随机微分方程的解关于正向随机微分方程的初值是具有连续性的,得到了最优控制和动态规划的一些结果,在这一章的最后还讨论了相应的效用函数的性质,如,效用函数的单调性、凹性以及风险规避性等;第五章,针对第一类倒向随机微分方程,运用单调迭代方法,证明了最大和最小解的存在性,并研究了解的其它性质及在效用函数上的应用。
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Experimental process, to determine the most suitable reaction temperature, the temperature in the most appropriate amount of catalyst to change and to identify the most suitable amount of catalyst, in the amount of catalyst and temperature conditions to determine the types of changes in solvent, and to compare the differences reflect under the conditions of the conversion rate of dimethyl sulfoxide.
实验过程中,先确定最适合的反应温度,在最合适的温度下改变催化剂的用量并确定最合适的催化剂用量,在催化剂的用量和温度确定的条件下改变溶剂的种类,并比较在不同反映条件下的二甲基亚砜的转化率。
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Both the two sides superior thyroid arteries were mainly arose from antero-endhymenine wall of genesis arteries (58.45%), inferior thyroid arteries of the thyrocervical trunk from endhymenine wall, and the ima thyroid arteries of genesis arteries all from anterior wall.
甲状腺上动脉源自起源动脉前内壁最多(58.45%);起源于甲状颈干的双侧甲状腺下动脉均源自其内侧壁;甲状腺最下动脉均源自起源动脉前壁。
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Finally, the paper provides the checking computations of themost dangerous cases of the cast ball-and-socket support node planned to be use in thedouble-layer reticulated dome roof of Laoshan Cycling Gymnasium for BeijingOlympic Games. The node under most dangerous cases is analyzed by ANSYS7.0 toget the distribution of stress and assurance coefficient. All these results can be thetheoretical warranty for the use of project of Beijing Olympic Games
最后,对北京奥运会老山自行车馆双层球面网壳柱脚拟采用的铸钢球铰支座节点在最不利工况下节点承载力进行了验算,并通过ANSYS7.0对节点在最不利工况下的应力分布进行分析得出了节点在这些工况下的安全系数从而为在北京奥运会老山自行车馆工程中使用这些节点提供了理论依据。
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At the end of the first month, they mate, but there is still one only 1 pair.
在一月底,最初的一对兔子交配,但是还只有1对兔子;在二月底,雌兔产下一对兔子,共有2对兔子;在三月底,最老的雌兔产下第二对兔子,共有3对兔子;在四月底,最老的雌兔产下第三对兔子,两个月前生的雌兔产下一对兔子,共有5对兔子;……如此这般计算下去,兔子对数分别是:1, 1, 2, 3, 5, 8, 13, 21, 34, 55,89, 144,。。。
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At the end of the first month, they mate, but there is still one only 1 pair.
&在一月底,最初的一对兔子交配,但是还只有1对兔子;在二月底,雌兔产下一对兔子,共有2对兔子;在三月底,最老的雌兔产下第二对兔子,共有3对兔子;在四月底,最老的雌兔产下第三对兔子,两个月前生的雌兔产下一对兔子,共有5对兔子;……&
- 推荐网络例句
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I didn't watch TV last night, because it .
昨晚我没有看电视,因为电视机坏了。
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Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.
今年以来,在北京的很多小区里,电梯液晶电视被撤了下来。
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I'm running my simile to an extreme.
我比喻得过头了。