消费习惯与中国经常项目差额波动研究

通过对经常项目的跨时最优现值模型进行扩展,将居民的消费习惯变量包含进了扩展模型并进行了实证检验.结果表明,模型的功效得到了显著改善,居民的消费习惯在中国经常项目的差额波动路径中起了重要作用.由于消费习惯的形成,居民更加关心消费的变化而不是消费水平,其跨时消费决策的结果则是储蓄大于投资.因此,缩小居民的收入差距、降低对未来的支出预期,逐步转变居民的消费习惯是调整中国经常项目差额波动的有效途径.     

细颗粒湍流聚并的分区法群平衡模拟

通过聚并促进细颗粒(PM2.5)特别是亚微米颗粒(PM1.0)团聚长大或被大颗粒捕集,是提高其脱除效率的有效方法之一.本文采用分区法对燃煤电厂尾部烟气中飞灰的聚并进行了群平衡模拟研究.利用圆柱阵列实现的湍流聚并装置,圆柱横向间距为4倍直径时,纵向间距宜在圆柱直径的15～30倍之间,在工程上较为可行的条件下,对于PM1....     

Nd∶YVO4/Nd∶GdVO4双波长激光器的功率均衡实验研究

实验研究了Nd∶YVO4/Nd∶GdVO4双波长激光器在不同抽运功率条件下,通过调节热沉温度达到功率均衡时的输出特性.实验结果表明:对于Nd∶YVO4/Nd∶GdVO4双波长激光器,当提高抽运功率,需要重新降低热沉温度达到功率均衡输出,降温幅度与抽运功率增加之比为11.23℃/W.与此同时,随着抽运功率和热沉温度的变化,双波长激光器的中心波长会出现小幅度的漂移,左峰波长随抽运功率增加的蓝移速率为0.056 nm/W,右峰波长随抽运功率增加的蓝移速率为0.054 nm/W.实验还发现功率均衡条件下激光器的输出总功率随抽运功率的增加而增加,拟合斜效率为8.7%,当抽运功率为5.58 W时,输出最大总功率达到115.7 mW.     

利用提升小波的蛋白质相互作用特征提取

利用提升小波从蛋白质序列中提取出它们相互作用的频谱特征,经支持向量机训练学习后,用于预测蛋白质间的相互作用.模拟计算结果表明,在阳性数据和阴性数据平衡的前提下,利用提升小波获取的低维蛋白质相互作用特征向量可以得到较高预测精度.进一步阐述了不同物种的蛋白质相互作用网络有着不同特征,为了得到更准确的预测结果,需要利用不同的方法提取蛋白质相互作用的特征.     

Bäcklund transformations and abundant exact explicit solutions of the Sharma-Tasso-Olver equation

By using an extension of the homogeneous balance method and Maple, the Bäcklund transformations for the Sharma-Tasso-Olver equation are derived. The connections between the Sharma-Tasso-Olver equation and some linear partial differential equations are found. With the aid of the transformations given here and the computer program Maple 12, abundant exact explicit special solutions to the Sharma-Tasso-Olver equation are constructed. In addition to all known solutions re-deriving in a systematic way, several entirely new and more general exact explicit solitary wave solutions can also be obtained. These solutions include (a) the algebraic solitary wave solution of rational function, (b) single-soliton solutions, (c) double-soliton solutions, (d) N-soliton solutions, (e) singular traveling solutions, (f) the periodic wave solutions of trigonometric function type, and (g) many non-traveling solutions. By using the Airy’s function and the Bäcklund transformations obtained here, the exact explicit solution of the initial value problem for the STO equation is presented. The variety of the structure of the solutions for the Sharma-Tasso-Olver equation is illustrated.     

Natural color low-level-light EBAPS imaging system based on three-color LCTF北大核心CSCD

The high-sensitivity electron bombarded active pixel sensor (EBAPS) not only has the characteristics of high gain and high sensitivity of vacuum imaging devices, but also has the digital characteristics of solid-state imaging devices, which greatly improves the level of night vision imaging. A natural color low-level-light EBAPS imaging system was built based on three-color liquid crystal tunable filter (LCTF). According to the characteristics of low-level-light images, the color enhancement processing such as grayscale stretching, white balance, and color correction was performed on the color images obtained by the system. The experimental results show that the system can realize the natural low-illumination color imaging that reflects the color characteristics of the scene itself, which can effectively improve the observation effect of the characteristics of the target scene at night, and can realize the color imaging under 5×10−4 lx illumination. © 2022 Editorial office of Journal of Applied Optics. All rights reserved.     

Light Emission and Scanning Electron Microscopic Characterization of Porous Silicon

Optical emission resulting from sputtered species during ion bombardment of porous and oxidized porous silicon targets has been studied. Samples were bombarded with 5‐keV Kr⁺ ions at an incidence angle of 70 degrees, and the light emitted was analyzed over the wavelength range 200–300 nm. The surface morphology was investigated, and the micrographs revealed grooves parallel to the plane of incidence when the porosity was surprisingly observed in the grooves under each pore. The results are discussed as a function of the incidence angle and the porosity of the silicon targets.     

Guaranteeing total balance in Metropolis algorithm Monte Carlo simulations

The condition of detailed balance has long been used as a proxy for the more difficult-to-prove condition of total balance, which along with ergodicity is required to guarantee convergence of a Markov Chain Monte Carlo (MCMC) simulation to the correct probability distribution. However, some simple-to-program update schemes such as the sequential and checkerboard Metropolis algorithms are known not to satisfy detailed balance for such common systems as the Ising model.     

State-Dependent Coupling in General Networks

In this paper we extend a result which holds for the class of networks of quasireversible nodes to a class of networks constructed by coupling Markov chains. We begin with a network in which the transition rates governing the stochastic behaviour of the individual nodes depend only on the state of the node. Assuming that the network has an invariant measure, we construct another network with transition rates at each node depending on the state of the entire network, and obtain its invariant measure.