Monte Carlo Hamiltonian: the Linear Potentials

We further study the validity of the Monte Carlo Hamiltonian method. The advantage of the method, in comparison with the standard Monte Carlo Lagrangian approach, is its capability to study the excited states. We consider two quantum mechanical models: a symmetric one $V(x) = |x|/2$; and an asymmetric one $V(x)=\infty$, for $x < 0$ and $V(x)=x$, for $x \ge 0$. The results for the spectrum, wave functions and thermodynamical observables are in agreement with the analytical or Runge-Kutta calculations.Comment: Latex file, 8 figure

Monte Carlo Hamiltonian

We suggest how to construct an effective low energy Hamiltonian via Monte Carlo starting from a given action. We test it by computing thermodynamical observables like average energy and specific heat for simple quantum systems.Comment: Contribution to Lattice'99 (Theoretical developments) Text (LaTeX file) + 2 figures (ps files

Establishment of a Numerical Model for Sulfate Attacked Concrete Considering Multi-factors

Sulfate attack is one of the major durability problems of concrete structures, which is manifested by expansive cracks and deterioration of cement paste. In this study, a numerical model is proposed to predict the process of ionic diffusion into concrete under external sulfate attack. The chemical reaction and diffusion processes are considered in this model. Furthermore, the influence of calcium leaching, chemical activity of multi-ions, temperature and changes in porosity are also taken into account. The initial porosity and tortuosity are assumed to be homogeneous in concrete, and the chemical potential gradient is regarded as the driving force for ions migrating in pore solution. The modified Davies equation is employed to quantize interaction effect among different ions in solution. A temperature dependent parameter is introduced in the diffusion process of sulfate ion. The dissolution of solid calcium is divided into two stages referring to solid-liquid equilibrium curve of calcium ion. One is the dissolution of the calcium hydroxide, and the other is the decalcification of the calcium silicate hydrate. The influence of calcium leaching on porosity is further considered in diffusion coefficient. Moreover, changes in porosity due to formation of expansive ettringite are also reflected in the diffusion coefficient. Finally, a new numerical model is established and a comparison of the model prediction with the experimental results has been conducted. It is demonstrated that the established diffusion-reaction model can provide a better deterioration assessment of concrete structures exposed to sulfate attack

Proportionate Recursive Maximum Correntropy Criterion Adaptive Filtering Algorithms and their Performance Analysis

The maximum correntropy criterion (MCC) has been employed to design outlier-robust adaptive filtering algorithms, among which the recursive MCC (RMCC) algorithm is a typical one. Motivated by the success of our recently proposed proportionate recursive least squares (PRLS) algorithm for sparse system identification, we propose to introduce the proportionate updating (PU) mechanism into the RMCC, leading to two sparsity-aware RMCC algorithms: the proportionate recursive MCC (PRMCC) algorithm and the combinational PRMCC (CPRMCC) algorithm. The CPRMCC is implemented as an adaptive convex combination of two PRMCC filters. For PRMCC, its stability condition and mean-square performance were analyzed. Based on the analysis, optimal parameter selection in nonstationary environments was obtained. Performance study of CPRMCC was also provided and showed that the CPRMCC performs at least as well as the better component PRMCC filter in steady state. Numerical simulations of sparse system identification corroborate the advantage of proposed algorithms as well as the validity of theoretical analysis

Analysis of changes in large-scale circulation patterns driving extreme precipitation events over the central-eastern China

To an extent, large-scale circulation situations and moisture transport are responsible for extreme precipitation occurrence. The aim of our study is to investigate the possible modifications of circulation patterns (CPs) in driving extreme precipitation over the central-eastern China (CEC). The self-organizing map (SOM) and event synchronization methods are used to link the extreme precipitation events with CPs. Results show that 23% of rain gauges have a significant change point (at the 90% confidence level) in annual extreme precipitation from 1960 to 2015. Based on the identified change points, we classified the data into two periods, that is, 1960–1989 and 1990–2015. Overall, CPs characterized by obvious positive anomalies of 500 hPa geopotential height over the Eastern Eurasia continent and negative values over the surrounding oceans are highly synchronized with extreme precipitation events. During 1990–2015, the predominant CPs are more related to the extreme precipitation with enhanced event synchronization. We found that the CP changes produce an increase in extreme precipitation frequency from 1960–1989 to 1990–2015

Auricular Reconstruction Using a Porous Polyethylene Framework

AbstractObjectiveTo report utility of Medpor frameworks in auricular reconstruction and management of frameworks protrusion.MethodsRetrorespectively analysis of clinical information in 31 patients who underwent auricular reconstruction from April 2000 to October 2002.ResultsAll 31 reconstructed auricles were in good condition at two weeks postoperatively. Framework protrusion occurred later in 11 patients. The framework was retained in 8 of these cases after secondary repair, but had to be removed in 3 patients. In 27 patients, the reconstructed auricle was rated as esthetically succesful.ConclusionMedpor framework protrusion is likely to occur when skin tension is high with minimal soft tissue coverage over the framework and can result from impact by strong external force. Despite the concern of protrusion, Medpor frameworks can be used in place of autologous cartilaginous graft in auricular reconstruction