Full counting statistics of phonon transport in disordered systems

The coherent potential approximation (CPA) within full counting statistics (FCS) formalism is shown to be a suitable method to investigate average electric conductance, shot noise as well as higher order cumulants in disordered systems. We develop a similar FCS-CPA formalism for phonon transport through disordered systems. As a byproduct, we derive relations among coefficients of different phonon current cumulants. We apply the FCS-CPA method to investigate phonon transport properties of graphene systems in the presence of disorders. For binary disorders as well as Anderson disorders, we calculate up to the 8-th phonon transmission moments and demonstrate that the numerical results of the FCS-CPA method agree very well with that of the brute force method. The benchmark shows that the FCS-CPA method achieves 20 times more speedup ratio. Collective features of phonon current cumulants are also revealed.     

用单光子计数系统检测微弱光信号

阐述了单光子计数实验中采用脉冲幅度甄别器和光子计数器测量光子数的实验原理,绘制了不同光照时间下的实验曲线,讨论了可能影响实验测量精度及产生误差的原因.     

Two-dimensional photon counting imaging detector based on a Vernier position sensitive anode readout

A two-dimensional photon counting imaging detector based on a Vernier position sensitive anode is reported. The decode principle and design of a two-dimensional Vernier anode are introduced in detail. A photon counting imaging system was built based on a Vernier anode. The image of very weak optical radiation can be reconstructed by image processing in a period of integration time. The resolution is superior to 100 μm according to the resolution test. The detector may realize the imaging of very weak particle flow of high-energy photons, electrons and ions, so it can be used for high-energy physics, deep space exploration, spectral measurement and bio-luminescence detection.     

Box－样条曲面的正性条件

研究了Ｂｏｘ－样条曲面的控制点与Ｂｏｘ－样条曲面的正性之间的关系．给出了Ｂｏｘ－样条曲面正性的必要条件、充分条件．由此我们得到了Ｂｏｘ－样条曲面的单调性条件，推广了Ｗ．ＤＡＨＭＥＮ和Ｃ．Ａ．ＭＩＣＣＨＥＬＬＩ在文［２］中给出的Ｂｏｘ－样条曲面的单调性结论     

同步辐射时间分辨荧光光谱技术

时间分辨光谱技术是研究原子、分子和凝聚态物质的激发动力学，特别是研究发光动力学的有力工具，文章主要介绍以同步辐射为激发光源研究时间分辨光谱的两种方法－时间相关单光子计数法和相移调制法，并比较了两者的优缺点。还讨论了同步辐射光源与其他激发光源相比的特点。     

Effects of experimental imperfections on a spin counting experiment

Spin counting NMR is an experimental technique that allows a determination of the size and time evolution of networks of dipolar coupled nuclear spins. This work reports on an average Hamiltonian treatment of two spin counting sequences and compares the efficiency of the two cycles in the presence of flip errors, RF inhomogeneity, phase transients, phase errors, and offset interactions commonly present in NMR experiments. Simulations on small quantum systems performed using the two cycles reveal the effects of pulse imperfections on the resulting multiple quantum spectra, in qualitative agreement with the average Hamiltonian calculations. Experimental results on adamantane are presented, demonstrating differences in the two sequences in the presence of pulse errors.     

THE POINT PROCESS OF STATETRANSITIONS IN AREGULAR MARKOV CHAIN

1.IntroductionInreliabilitytheory,inordertocalculatethefailurefrequencyofarepairablesystem,Shily]firstintroducedandstudiedthetransitionfrequencybetweentwodisjointstatesetsforafiniteMarkovchainandavectorMarkovprocesswithfinitediscretestatespaceandobtainedageneralformulaoftransitionfrequency.Then,ontheconditionthatthegeneratormatrixofMarkovchainisuniformlybounded,Shi[8'9]againprovedthetransitionfrequencyformulaandobtainedthreeotherusefulformulas.Obviously,thepoint(orcalledcounting)processofsta…     

Weierstrass型函数图象的分形维数

考虑函数f(x)=sum from i=1 to ∞(?)~(-1)φ((?) θ_n)和w(x)=sum from n=1 to ∞(?)φ_(?)((?)x θ_(?)),式中0<α<(?)是任意实数,在一定条件下,估计了函数f图象的Hausdorff维数的下界,并求得了w函数图象的Box维数和Packing维数。