The Degasperis-Procesi equation with self-consistent sources

The Degasperis-Procesi equation with self-consistent sources(DPESCS) is derived. The Lax representation and the conservation laws for DPESCS are constructed. The peakon solution of DPESCS is obtained.Comment: 15 page

Preparation of MAl2O4: Eu2+, Sm3+ (M = Ca, Sr, Ba) Phosphors by the Combustion Method and their Luminescent Properties

A series of MAl2O4: Eu2+, Sm3+ (M = Ca, Sr, Ba) phosphors was prepared by the combustion method, and the influence of these alkaline earth metals on the structure and luminescent performances for these phosphors was investigated. A relationship was established between their composition, crystallization capacity and luminescent properties. The results show that the CaAl2O4: Eu2+, Sm3+ and SrAl2O4: Eu2+, Sm3+ phosphors exhibit monoclinic crystal systems and that the BaAl2O4: Eu2+, Sm3+ phosphor exhibits a hexagonal structure. The alkaline earth metal has a positive effect on the crystallization process, the heat treatment procedure and the luminescent properties of the corresponding phosphors. According to the order Ca > Sr > Ba, the maximum emission wavelengths of the corresponding phosphors are found at 505 nm, 490 nm and 478 nm, and the relevant colours of emitted light are between blue and green, which indicates that there is a clear blue shift in the emission spectra, but their excitation spectra show almost no difference. The decay curve shows that the afterglow intensity and time are not only related to the activating processes and the hole transport, but also to the phase structure and the grain size,which is in the order Sr>Ca>Ba.Keywords: Long afterglow, alkaline earth aluminates, spectra, combustion metho

Wearable Sensor Data Based Human Activity Recognition using Machine Learning: A new approach

Recent years have witnessed the rapid development of human activity recognition (HAR) based on wearable sensor data. One can find many practical applications in this area, especially in the field of health care. Many machine learning algorithms such as Decision Trees, Support Vector Machine, Naive Bayes, K-Nearest Neighbor, and Multilayer Perceptron are successfully used in HAR. Although these methods are fast and easy for implementation, they still have some limitations due to poor performance in a number of situations. In this paper, we propose a novel method based on the ensemble learning to boost the performance of these machine learning methods for HAR

Hole Doping Dependence of the Coherence Length in La2−xSrxCuO4La_{2-x}Sr_xCuO_4 Thin Films

By measuring the field and temperature dependence of magnetization on systematically doped $La_{2-x}Sr_xCuO_4$ thin films, the critical current density $j_c(0)$ and the collective pinning energy $U_p(0)$ are determined in single vortex creep regime. Together with the published data of superfluid density, condensation energy and anisotropy, for the first time we derive the doping dependence of the coherence length or vortex core size in wide doping regime directly from the low temperature data. It is found that the coherence length drops in the underdoped region and increases in the overdoped side with the increase of hole concentration. The result in underdoped region clearly deviates from what expected by the pre-formed pairing model if one simply associates the pseudogap with the upper-critical field.Comment: 4 pages, 4 figure

Critical Current Density and Resistivity of MgB2 Films

The high resistivity of many bulk and film samples of MgB2 is most readily explained by the suggestion that only a fraction of the cross-sectional area of the samples is effectively carrying current. Hence the supercurrent (Jc) in such samples will be limited by the same area factor, arising for example from porosity or from insulating oxides present at the grain boundaries. We suggest that a correlation should exist, Jc ~ 1/{Rho(300K) - Rho(50K)}, where Rho(300K) - Rho(50K) is the change in the apparent resistivity from 300 K to 50 K. We report measurements of Rho(T) and Jc for a number of films made by hybrid physical-chemical vapor deposition which demonstrate this correlation, although the "reduced effective area" argument alone is not sufficient. We suggest that this argument can also apply to many polycrystalline bulk and wire samples of MgB2.Comment: 11 pages, 3 figure

Investigating the factors affecting the residential satisfaction of new-generation migrants: a case study of Hangzhou in China

This paper examines the residential satisfaction of new-generation migrants in the Chinese context. The study uses the survey data of residential satisfaction of new-generation migrants in Hangzhou. The ordered logit model is employed to examine the factors affecting the residential satisfaction of new-generation migrants, a special group of the workforce in metropolitan cities of China. Unlike the previous studies of residential satisfaction of rural migrant workers in Chinese cities, we find that the residential satisfaction of new-generation migrants does follow the standard patterns identified in the literature; the socio-demographic attributes such as gender, education, income, housing characteristics of size and the quality of kitchen and sanitary facilities and neighbourhood environment and location factors such as the distance to work place, accessibility to employment and other location and the availability of entertaining amenities are significant determinants of residential satisfaction of new-generation migrants. Additionally, the institutional factors such as tenancy agreement signed with landlord and lease length, which provides tenants with residential stability and security have a significant impact on residential satisfaction. This finding has policy implication of regulating the growing rental housing market in China. This finding also complements the existing research on residential satisfaction