亚洲多学科古气候研究

近年来的事实表明,陆相地层记录较之冰芯和深海钻孔能够提供时、空分辨率更高的古气候信息。亚洲大陆已积累了大量的数据,不过在时间分辨率上仍有待进一步改善。对亚洲大陆上各种陆相记录,如冰碛物、黄土、湖相沉积等都做了研究工作。其中,日本琵琶湖研究工作是迄今最为全面的多学科综合研究。中国和中亚地区,对2Ma来的黄     

Onboard performance of the RT-2 detectors

The RT-2 Experiment onboard the CORONAS-PHOTON satellite is designed to study the spectral, temporal, and spatial details of solar hard X-ray flares in the 15–150 keV range. Above this energy (and upto 1000 keV), it also acts as an omni-directional gamma-ray detector with a capability to study gamma-ray bursts (GRB), bright solar flares, and X-ray pulsars. With an ensemble of hard X-ray detectors with different fields of view and coding devices, it also has the capability to investigate the spectrum of Cosmic Diffuse X-ray Background. The performance of the detectors from 2009 February to November is described in this paper. Results obtained on a few GRBs and solar flares are also briefly discussed.     

The GH branch of PKP from deep-focus earthquakes

summary . Approximately 1000 PKP observations in the range 110° < Δ < 170° have been statistically studied to examine the existence of Bolt's GH branch of the PKP travel-time curve. Data give firm evidence for the existence of this branch from 130 to 153° but the possibility of its extending further cannot be ruled out. Observations for this branch fit the form:
Where a =(1150.3254±0.5328)s, b = (16.4907±0.3803)s, c = (−0.1316±0.0630)s.
Times for this branch are always greater by 2 s than the corresponding Gogna times from Pacific earthquakes.     

Certain vacuum Bianchi-type models in a new relativistic theory of gravitation

The vacuum Bianchi type-I, III, V, VI₀ and Kantowski-Sachs models have been obtained in a new scalar-tensor theory formulated by Lau and Prokhovnik (1986) under the assumption of a certain relationship between the cosmological term and the scalar field . The dynamical behaviour of these models have been studied.     

Is climate change impacting Rideau Canal Skateway,the world’s longest skating rink?

Natural Hazards - When disaster occurs in coal mines, the complex network structure of roadways and the disaster evolution process usually cause serious casualties. An efficient escape plan becomes...     

Heat and mass transfer in rotating fluid with Hall current,II

Effects of Hall current on the hydromagnetic free-convection resulting from the combined effects of thermal and mass diffusion of an electrically conducting liquid past an infinite vertical porous plate in a rotating frame of reference have been analysed. As the mean steady flow has been presented in Part I, only the solutions for the transient primary and secondary velocity profiles, transient temperature profiles in the boundary layer and the transient skin friction, the transient rate of heat transfer on the plate are presented in this work. The influence of the different parameters entering into the problem are discussed.     

Backscatter laser velocimeter for energetic bottom boundary layers: The optical signal

The optical signal from a dual-beam backscatter laser Doppler velocimeter designed for oceanographic usage will be described both theoretically and experimentally. The instrument was constructed to simulate, in the laboratory, the strength and behavior of the optical signal as a function of mass concentration of natural particles in water-a subject of concern in the study of high energy benthic boundary layers. It has been found that with proper design, the predominant mode of signal degradation with increasing particle loading is caused primarily by increased shot-noise due to signal attenuation alone. Secondly, the signal is observed to be in the single-scatterer mode at particle concentrations of up to 5 mg/l. Variations in observed signal-to-noise ratio will be described and compared with theoretical calculations.     

Unsteady free-convective flow and mass transfer in a rotating porous medium with Hall current,I

The Hall effect on the unsteady hydromagnetic free-convection resulting from the combined effects of thermal and mass diffusion of an electrical-conducting liquid through a porous medium past an infinite vertical porous plate in a rotating system have been analysed. The expressions for the mean velocity, mean skin friction, and mean rate of heat transfer on the plate are derived. The effects of magnetic parameterM, Hall parameterm, Ekman numberE, and permeability parameterK ^* on the flow field are discussed with the help of graphs and tables.Nomenclature C _p specific heat at constant pressure - C the species concentration inside the boundary layer - C _w the species concentration at porous plate - C the species concentration of the fluid at infinite - C dimensionless species concentration - D chemical molecular diffusivity - E Ekman number - Ec Eckert number - g acceleration due to gravity - Gr Grashof number - Gm modified Grashof number - H ₀ applied magnetic field - (J _x, J_y, J_z) components of current density - M magnetic parameter - m Hall parameter - P Prandtl number - q _m mean rate of heat transfer - Sc Schmidt number - t time - t dimensionless time - T temperature of fluid - T _w temperature of the plate - T temperature of fluid at infinite - T dimensionless temperature - (u, v, w) components of the velocityq - w ₀ suction velocity - (x, y, z) Cartesian coordinates - z dimensionless coordinate normal to the plate Greek symbols coefficient of volume expansion - * coefficient of thermal expansion with concentration - frequency - dimensionless frequency - k thermal conductivity - K ^* permeability parameter - dinematic viscosity - density of the fluid in the boundary layer - coefficient of viscosity - _e magnetic permeability - angular velocity - electrical conductivity of the fluid - _m mean skin friction - _mn mean skin friction in the direction ofx - _mv mean skin friction in the direction ofy