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The dispersion relation and the speed of linear magnetosonic wave are given in the present paper. Furthermore, an arbitrary amplitude nonlinear magnetosonic solitary wave is studied. It is found that the amplitude of the magnetosonic solitary wave cannot be larger than a critical value. It is found that the maximum speed of the magnetosonic solitary wave is about 1.24 times that of the Alfvén wave speed when the magnetic field is sufficiently strong so that the magnetic pressure is much larger than the fluid pressure. On the other hand, the maximum perturbed magnetic field is just equal to the external magnetic field if the magnetic pressure is much larger than the fluid pressure. It suggest that the variation regime of the perturbed magnetic field is (0 , B 0) , while the variation regime of the speed of magnetosonic solitary wave is (v A , 1.24 v A) in the upstream and downstream regions of the Venusian bow shock. Here B 0 and v A represent the background magnetic field and the Alfvén wave speed, respectively. [ABSTRACT FROM AUTHOR]

The loss rate of ion beams and the non-neutral plasma in an axisymmetric magnetic mirror is investigated in the present paper. It is found that the loss rate increases as the mass of the ions increases for a ion beam confined in a magnetic mirror. Moreover, both the electron loss rate and the ion loss rate are obtained when a non-neutral plasma is confined in a magnetic mirror. It seems that both loss rate remain unchanged in the regime when the electron number density is less than that of the ions. In the other regime that the electron number density is much larger than that of the ion number, the ion loss rate increases with the increase of electron number density, while the electron loss rate decreases as the electron number density increases. This result may help us to devise a mirror to separate the different charged particles by confining these different particles in a magnetic mirror. The electron loss rate and the ion loss rate are obtained when a non-neutral plasma is confined in a magnetic mirror. It seems that both loss rate remain unchanged in the regime when the electron number density is less than that of the ions. In the other regime that the electron number density is much larger than that of the ion number, the ion loss rate increases with the increase of electron number density, while the electron loss rate decreases as the electron number density increases.. [ABSTRACT FROM AUTHOR]

The propagation of dust-acoustic waves in a dusty plasma bounded in finite symmetrical cylindrical geometry has been theoretically investigated. By using the reductive perturbation method, we obtain a quasi-nonlinear Schrödinger equation. It is shown that there is a dark envelope soliton under certain conditions, while its amplitude will decrease with the time. The dependence of both the dispersion relation and group velocity of envelope solitary waves on the radius of cylinder has been given. Moreover, we define the duration time of dark envelope solitons and give the theoretical ones. It is found that the duration time increases as the radius of cylinder increases, while it decreases as the viscosity coefficient of dusty plasmas increases. [ABSTRACT FROM AUTHOR]

A crucial region for China's 'Grain-for-Green Policy' is located within a traditional farmpastoral area, between 2000 to 3000 m above sea level, on the eastern Qinghai-Tibetan Plateau. However, the responses of soil organic carbon (SOC) to different land-use patterns in this region are unclear. Here, we determined the SOC (0-20 cm) content of grasslands and forests that are being converted from farmlands, as well as in abandoned arable land and arable land in this region. The factors influencing the reclaimed lands were analyzed along altitudes from 2030 to 3132 m. Our results showed that SOC content was higher for grassland and abandoned arable land than forest and arable land. The SOC content increased with the increase in altitude for total land-use patterns. Further, the grassland and abandoned arable land had higher SOC content than the forest with almost parallel trends along the increase in altitude. However, the proportion of regulated factors of altitude and species richness varied among forest, grassland, and abandoned arable land. Our results indicated that the land-use pattern of returning farmland to grassland and abandoned arable land was more effective in terms of the SOC storage in the superficial layer in this altitude range in the Qinghai-Tibetan Plateau, thereby being beneficial to optimizing land management in this region. [ABSTRACT FROM AUTHOR]

The adsorption behaviors of three carboxyl hydroxamic acids on diaspore (010) and kaolinite (001) have been studied by density functional theory (DFT) and molecular dynamics (MD) method. The results indicated that carboxyl hydroxamic acids could adsorb on diaspore surface by ionic bonds and hydrogen bonds, and adsorb on kaolinite surface by hydrogen bonds. The models of carboxyl hydroxamic acids adsorbed on diaspore and kaolinite surfaces are proposed. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

By using particle-in-cell(PIC) simulation method, the proton beam confinement in a magnetic mirror is investigated in the present paper. We define two physical quantities to describe the confinement effects of mirror for proton beam. One is loss rate χ=Nlost/N0, where Nlost is the number of leaked particles from the mirror and N0 is the number of initial particles. The other is confinement time τm. Dependences of loss rate and confinement time on the parameters of both magnetic mirror and proton beam is given. It is found that the larger the mirror ratio, the less the loss rate, and the longer the confinement time. The appropriate proton beam velocity and other parameters of the protons can significantly improve the confinement time of the mirror and the efficiency of confinement. [ABSTRACT FROM AUTHOR]