某型高性能常规涡轮对转改型研究

本文对某高性能常规涡轮开展了对转改型研究。首先对该常规涡轮进行基本分析,详细探讨了将其改进为1+1及1+1/2对转涡轮(无低压涡轮导叶)时遇到的关键问题,并给出了一些解决问题的方案.研究表明,1+1对转方案现实可行,1+1/2对转方案将很难实现.在方案研究的基础之上,本文进行了保留过渡段的1+1对转涡轮详细设计并采用三维黏性程序对其性能进行了初步的分析。     

一道经典光学高考题的3种解法和教学启示

对2 0 1 1年高考新课标卷第3 4题进行了另解, 并根据费马原理对该题进行了赏析     

1+1/2对转涡轮设计及控制方法探索

本文对 1 1/2对转涡轮试验件进行了详细设计,并对其控制问题进行了初步探讨,结果表明所设计 1 1/2对转涡轮基本达到设计要求,其控制问题由高压静叶可调和尾喷管面积调节共同解决。     

双膜热流计在涡轮换热实验中的应用

一、概述 在文献[1]中曾对双膜热流计进行了理论分析,并得到分析解为式中B是温度历史_1(t)、_2(t)以及综合参数2(1/ρck)和l/2(1/α)的函数。本文在此基础上,对双膜热流计在涡轮换热实验中的应用,以及对数据的粗略估算进行了讨论,并对实验结果进行了分析.     

一种薯蓣皂苷的NMR研究

从七叶一枝花中分离得到一种薯蓣皂苷薯蓣皂苷元3-O-α-L-阿拉伯呋喃糖基- (1→4)-α-L-鼠李吡喃糖基(1→2)-β-D-葡萄吡喃糖苷. 应用1D和2D NMR 实验技术（包括¹H-¹H COSY, HSQC和HMBC）对化合物结构进行研究,对其¹H和¹³C化学位移进行了完全归属. 实验中运用了选择性1D TOCSY技术对糖环的质子峰进行了归属.     

再谈由留数定理求解的两类无穷积分

受到文章[1]的启发,本文再次探讨由留数定理求解的两类无穷积分.首先分析两类积分的特征,并通过对文献[1]的方法进行梳理和简化,用留数定理对两类积分进行了处理,得到了n大于1且为整数情况下的结果,然后通过多值函数留数定理的方法对两类积分进行了重新计算,得到n大于1情况下的结果,并对结果进行了简要的说明.通过两种方法对积分的处理,体会留数定理的妙处,拓展学生的视野,提升学习的热情,为后续课程打好基础.     

S_(10)、S_(11)和S_(12)结构的半经验分子轨道方法研究

主要用AM 1半经验分子轨道方法对S1 0 、S1 1 和S1 2 的几何结构进行了计算 ,并比较了不同构型的稳定性。     

三七中2个微量人参皂苷的NMR信号全归属

从三七根的80%乙醇提取物中,分离并鉴定了2个人参皂苷类化合物,分别为6-O-(β-D-glucopyranosyl)-20-O-(β-D-xylopyranosyl)-3β,6α,12β,20(S)-tetrahydroxydammar-24-ene(化合物1)和notoginsenoside U(化合物2).应用1D和2D NMR(1H-1H COSY、HSQC和HMBC)对这2种化合物的结构进行解析,对化合物1的13C NMR文献报道数据进行了修正与讨论,并对化合物1的1H NMR数据进行全归属.同时在2D NMR的基础上对化合物2在氘代吡啶溶液中的1H NMR和13C NMR数据进行全归属.     

一道考查学生物理思维方法的好题

对2 0 1 6年高考天津卷的第1 1题进行了深入浅出地分析, 并给出了多种解法供大家参考     

1+1/2对转涡轮叶排轴向间距对性能影响的研究

木文对1+1/2对转涡轮中轴向间距影响进行了初步研究。对不同轴向间距叶栅流场进行了大量时间精确模拟。研究表明,1+1/2对转涡轮高低压转叶间轴向间距成为追求高效率的制约因素,轴向间距为高压转叶喉部宽度是关键点。因此有关小轴向间距下强激波/叶排干扰的研究应该加强。     

A generalized field theory

Three solutions with spherical symmetry are obtained for the field equations of the generalized field theory established recently by Mikhail and Wanas. The solutions found are in agreement with classical known results. The solution representing a generalized field, outside a spherical symmetric charged body, is found to have an extra term compared with the Reissner-Nordström metric. The space used for application is of type FIGI, so the solutions obtained correspond to a field in a matter-free space. A brief comparison between the solutions obtained and those given by other field theories is given. Two methods have been used to get physical results: the first is the type analysis, and the second is the comparison with classical known results by writing down the metric of the associated Riemannian space.     

A new proof of the positive energy theorem

A new proof is given of the positive energy theorem of classical general relativity. Also, a new proof is given that there are no asymptotically Euclidean gravitational instantons. (These theorems have been proved previously, by a different method, by Schoen and Yau.) The relevance of these results to the stability of Minkowski space is discussed.Research partially supported by NSF Grant PHY78-01221     

一类时滞竞争系统的定性分析

本文考虑具有连续时滞的Lotka-Volterra竞争系统。给出了该系统的稳定性分析。利用Hopf分支定理,我们证明了由时滞引起的不稳定性可以导致系统产生稳定的极限环。利用Birkhoff定理证明了系统可能出现循环解。最后,我们给出数值实例,验证了上述结果。     

带电粒子在偶极子电场中的运动

求得了带电粒子在电偶极子产生的电场中的径向运动方程 ,分析了带电粒子在该电场中各种可能的运动规律     

A necessary and sufficient condition for transforming autonomous systems into linear autonomous Birkhoffian systems

The problem of transforming autonomous systems into Birkhoffian systems is studied. A reasonable form of linear autonomous Birkhoff equations is given. By combining them with the undetermined tensor method, a necessary and sufficient condition for an autonomous system to have a representation in terms of linear autonomous Birkhoff equations is obtained. The methods of constructing Birkhoffian dynamical functions are given. Two examples are given to illustrate the application of the results.     

A4 Compton polarimetry

For the A4 parity violation experiment at MAMI we have installed a Compton laser polarimeter in our beam line. We have now operated this polarimeter at different beam energies of 315, 855, and 1508 MeV. A short overview of our detectors for scattered photons and electrons is given, together with a discussion of the extraction of Compton asymmetries using tagged photon spectra.     

桶式离子源参数计算

桶式离子源具有很多优越性,是一种新的有广泛应用价值的离子源。为了研究聚变等离子体中性注入用的离子源,本文对桶式离子源的参数做了系统的计算,给出了实用的计算公式。     

A family of Jordan-Brans-Dicke Kerr solutions

A family of solutions of the vacuum Jordan-Brans-Dicke or scalar-tensor gravitational field equations is given. This family reduces to the Kerr rotating solution of the vacuum Einstein equations when the scalar field is constant. The family does not have spherical symmetry when the rotation is zero and the scalar field is not constant. The method used to generate the new solutions can also be used to obtain vacuum Jordan-Brans-Dicke solutions from any given vacuum stationary, axisymmetric solution.     

调相聚焦激光加速器的调相模拟实验

在本文中讨论了调相聚焦激光加速器的调相模拟实验方案,给出了调相板的具体设计方法,制作了调相板,并进行了调相实验。实验结果与理论设计相符合。 关键词：     

A unified symmetry of nonholonomic mechanical systems in phase space

In this paper, we have studied the unified symmetry of a nonholonomic mechanical system in phase space. The definition and the criterion of a unified symmetry of the nonholonomic mechanical system in phase space are given under general infinitesimal transformations of groups in which time is variable. The Noether conserved quantity, the generalized Hojman conserved quantity and the Mei conserved quantity are obtained from the unified symmetry. An example is given to illustrate the application of the results.