随机时滞Schr dinger格点系统的周期测度

考虑具有时滞的随机Schr dinger格点系统的周期测度.首先给出解的存在唯一性,然后得出解的一致估计以建立解的概率分布族的胎紧性.最后,当系统的时间相关项在时间上是周期性时,证明周期测度的存在性.

区域科技创新中短周期测度研究

区域科技创新波动性与周期性的界定和测度是创新经济学基础理论研究领域的一个亟待深入探讨的问题。目前大多数学者对于区域科技创新的研究主要基于静态层面,而区域科技创新是一个动态、复杂的系统过程。基于熊彼特的创新周期理论,区域科技创新波动性与周期性的内涵界定,构建了区域科技创新波动与周期测度的工具和模型,运用统计改革后的深圳南山区科技创新季度数据对区域科技创新短期的波动性与周期性及其特征进行了全面的测度。结果表明:区域科技创新波动具有周期性,不同阶段的创新波动与周期特征完全不同,政府应根据区域科技创新波动规律与周期性规律,采取更具时效性的科技创新政策。

我国制造业高质量发展周期测度

文章从制造业高质量发展的基本内涵出发,构建了优规模、优结构、高效率、高效益的四维评价指标体系;运用合成指数法得到我国制造业高质量发展一致景气指数,并分析其波动性和周期性。结果显示:我国制造业高质量发展的周期性波动变化特征主要体现在波动持续的时间、波动幅度与离散度三个层面;三个层面中包含的波动高度、深度、频率及振幅等指数呈现周期性波动变化的特征;观测期初期表现为陡升陡降的变化态势,中后期波动性变化趋于稳定,整体表现出非对称性;虽然制造业高质量发展一致景气指数在短期内受到一定影响,但长期发展趋于稳定。

中国煤炭产业景气测度及其运行特征分析

文章基于主成分分析方法,从煤炭供给、煤炭市场、煤炭效益、生产要素四个方面构建反映煤炭产业景气周期的指标体系,利用1953—2016年的产业数据,对我国煤炭产业景气进行测度,划分为十个产业景气周期。并在产业景气周期特征分析的基础上,探寻煤炭产业景气的运行规律。

链双曲同宿类上周期偏差现象的研究

具有链双曲性质的同宿类,它是部分双曲系统中最典型也是人们研究最多的一类。本文研究的是此类集合上具有偏差性质的周期轨道,我们将利用广义测度熵这个新概念来刻画偏差周期轨的指数增长率。

Effect of Temperature Variation on the Separation of Sesamin and Sesamolin by Simulated Moving Bed

In this work, sesamin and sesamolin is separated and purified by SMB （simulated moving bed） chromatography. Purity of sesamin and sesamolin can reach 99.2% and 99.9 %, and they can be recovered by 99.9% and 99.4%, respectively. Concentrations of the extract and raffinate was monitored and periodical change of the concentration was observed on experiment. Effects of non-linear adsorption, dead volume, and temperature on the separation are reviewed by the triangle theory to explain the periodical change of concentration. It is found that dead volume has little effect, and temperature fluctuation significantly affects thc separation by SMB. The temperature seriously affects the robust operation of SMB due to the change of Henry＇s constant, which will change the selectivity and restrain the productivity. Although the productivity in this study is only 0.0416 g/L-hr, the cost of the stationary phase used in this study is much lower than that of packed in analytical column. By using this stationary phase, the authors are still able to separate the mixture of sesamin and sesmolin. This will economically attract attention for the application of SMB to purify bioactive compounds on developing botanical drugs.

Application of predictive control scheduling method to real-time periodic control tasks overrun

Based on the abort strategy of fixed periods, a novel predictive control scheduling methodology was proposed to efficiently solve overrun problems. By applying the latest control value in the prediction sequences to the control objective, the new strategy was expected to optimize the control system for better performance and yet guarantee the schedulability of all tasks under overrun. The schedulability of the real-time systems with p-period overruns was analyzed, and the corresponding stability criteria was given as well. The simulation results show that the new approach can improve the performance of control system compared to that of conventional abort strategy, it can reduce the overshoot and adjust time as well as ensure the schedulability and stability.

Parametric study on collapse margin ratio of structure

The determination of collapse margin ratio(CMR)of structure is influenced by many uncertain factors.Some factors that can affect the calculation of CMR,e.g.,the elongation of the structural fundamental period prior to collapse,the determination of earthquake intensity measure,the seismic hazard probability,and the difference of the spectral shapes between the median spectrum of the ground motions and the design spectrum,were discussed.Considering the elongation of the structural fundamental period,the intensity measure Sa(T1)should be replaced with *aS in the calculation of CMR for short-period and medium-period structures.The reasonable intensity measure should be determined by the correlation analysis between the earthquake intensity measure and the damage index of the structure.Otherwise,CMR should be adjusted according to the seismic hazard probability and the difference in the spectral shapes.For important long-period structures,CMR should be determined by the special site spectrum.The results indicate that both Sa(T1)and spectrum intensity(SI)could be used as intensity measures in the calculation of CMR for medium-period structures,but SI would be a better choice for long-period structures.Moreover,an adjusted CMR that reflects the actual seismic collapse safety of structures is provided.

Measurement of the Variation of Shear Velocity on Bed during a Wave Cycle

Almost all works in the field of boundary layer flow under the breaking wave consider the flow similar as the flow in an oscillating pressure tube. Although the two flows are similar, there are many differences. The results achieved in such manner are therefore also only similar to the results that can be achieved during measurements in the surf zone. Present article deals with boundary layer measurements on an inclined bottom under breaking waves. The measurements over the whole wave cycle were carried out, and the shear velocity under the breaking wave was calculated based on the measurements. It was found that there is a considerable space and time variation of the term in the surf zone. The turbulence generated during the wave breaking changes the shape of the shear velocity profile in comparison to the profile measured before breaking. As the values of shear velocity are directly correlated with the description of the whole velocity field in the wave, it can be assumed that the enhanced description of the shear velocity results in better understanding of the whole velocity field under breaking waves. Therefore, the article brings a new insight into the field and aims to make a discussion about the need to rethink the way of describing the boundary layer flow in the surf zone.

Development of a Seismometer-Type Absolute Displacement Sensor Aimed at Detecting Earthquake Waves with a Large Magnitude and Long Period

This paper proposes a novel seismometer-type absolute displacement sensor aimed at detecting earthquake waves with a large magnitude and long period. However, since the measuring range of the displacement sensor is higher than its natural frequency, it is difficult to detect low frequency vibrations below 1 Hz using a conventional a seismic-type displacement sensor. In order to provide an absolute displacement detection which is capable of lowering the natural frequency and enlarging the detectable amplitude without causing structural defects, the relative signals of displacement, velocity, and acceleration between a detected object and the auxiliary mass of the sensor are fed back into the sensor. In addition, phase lag compensation is inserted to adjust phase angles, which are of a frequency of 1 Hz. According to simulation results, a detection range from 0.1 Hz to 50 Hz is expected. It has been demonstrated that the developed sensor with a small size and light weight has a detection range of from 0.5 Hz to 50 Hz for absolute displacement and velocity. As an additional advantage, the measurement displacement amplitude has been expanded to about 20 dB. This sensor is available to use for the active control method. of flexible structures like high rise buildings using the LQ control

Parameters optimization of π-phase-shifted long-period fiber grating for gas sensing

The gas-sensitive film coated π-phase-shifted long-period fiber grating(LPFG),consisting of two same long-period fiber gratings cascaded by a regular fiber with length of half of the grating period,is proposed for gas sensing.The sensitivity of the sensor is defined by the change rate of the transmission at specific wavelength with respect to the film refractive index.The qualitative and numerical analyses show that to get a high sensitivity,the optimal coupling strength of each long-period fiber grating is √2 π/4.With this coupling strength,the longer the grating is,the higher sensitivity the sensor has.By choosing appropriate grating period,a high sensitivity for the film with a certain refractive index and thickness can be attained.