27 research outputs found
Modelling coupled seepage-erosion-deformation processes in soils with Smoothed Particle Hydrodynamics (SPH)
No full textFormation and dominant factors of haze pollution over Beijing and its peripheral areas in winter
No full textAbstractThe formation process and dominant factors of air pollution over Beijing and its immediate vicinities, known as a rapidly developed agglomeration, were dissected and analyzed in multi–scale in this paper. Several severe haze pollution events occurred over northern China in October, November 2013, during which time a set of hourly sampling data, including four air pollutants (PM2.5, PM10, NO2, SO2) from 35 monitoring stations, as well as relevant vertical profiles of meteorological parameters were collected. Two major formation processes were found to be contributing to two substantial different pollution types in Beijing area. One type was characterized by stagnant weather conditions with moderate southerly winds. Air pollutants from local and southern industrial provinces accumulated and PM2.5 concentrations were less than 250μg/m3, with a duration of 1 or 2 days. In contrast, the second type was characterized by intense temperature inversion under planetary boundary layer (PBL) and natural dusts in the middle and upper part of PBL transported from Gobi Desert cover the fine particle like a “lid”, making the regional atmospheric layers extremely stable. Consequently, PM2.5 concentrations exceeded 400μg/m3 and the severe pollution can last for 3 to 5 days. Moreover, domestic heating is a significant contributor to haze pollution in winter. Its role was estimated using comparative methods as it began in the middle of observing period. Statistical results showed that domestic heating contributed to the increase in most of the monitored air pollutants, especially for SO2. Spatial interpolation and overlay analysis were conducted to get the spatial features of domestic heating–induced pollutants in order to clarify its sources. Population distribution data was integrated into a spatial statistical analysis, which indicated the concentrations of PM2.5 and SO2 have no or even negative relationship with population, thus revealing pollutants from domestic heating in Beijing were mainly from suburban areas without central heating systems
Global Stability of a Markovian Jumping Chaotic Financial System with Partially Unknown Transition Rates under Impulsive Control Involved in the Positive Interest Rate
No full textThe intrinsic instability of the financial system itself results in chaos and unpredictable economic behavior. To gain the globally asymptotic stability of the equilibrium point with a positive interest rate of the chaotic financial system, pulse control is sometimes very necessary and is employed in this paper to derive the globally exponential stability of financial system. It should be pointed out that the delayed feedback model brings an essential difficulty so that the regional control method has to be adopted. In this paper, the author firstly employs impulsive control, regional control, the Lyapunov function technique, and variational methods to derive the stochastically globally asymptotic stability criterion of the economic balance point with a positive interest rate for a delayed feedback financial system with Markovian jumping and partially unknown transition rates. Besides, the mathematical induction method and the proof by contradiction are applied synthetically to deduce the globally exponential stability of the equilibrium point with a positive interest rate for the impulsive financial system without time-delays. Moreover, numerical examples illustrate that under suitable data conditions on the two main criteria mentioned above, the interest rates are positive decimals when the financial system reaches stability, which means better economic significance
The Application of 4C Training Model in the Operating Room Nurse Training
No full textThe operating room is an important place for the treatment of patients undergoing surgery, the quality level of clinical nursing has a direct influence in the therapeutic effect of patients. In the present study, four components instructional design mode (4C training mode) was applied in the training of professional nurses in the operating room, it involved the following aspects: regular skill knowledge analysis, goals setting, as well as the construction and implementation of the project. Targeted training methods and training content were formulated in accordance with the learning ability and knowledge reserve of different professional nurses, and different skills required to master, to fully mobilize the enthusiasm and initiative of nurses, thereby to improve the operation and comprehensive level of nurses in the operation room to achieve good results
The Application of 4C Training Model in the Operating Room Nurse Training
No full textThe operating room is an important place for the treatment of patients undergoing surgery, the quality level of clinical nursing has a direct influence in the therapeutic effect of patients. In the present study, four components instructional design mode (4C training mode) was applied in the training of professional nurses in the operating room, it involved the following aspects: regular skill knowledge analysis, goals setting, as well as the construction and implementation of the project. Targeted training methods and training content were formulated in accordance with the learning ability and knowledge reserve of different professional nurses, and different skills required to master, to fully mobilize the enthusiasm and initiative of nurses, thereby to improve the operation and comprehensive level of nurses in the operation room to achieve good results
Development and validation of an LC–MS/MS method for the determination of hinokiflavone in rat plasma and its application to a pharmacokinetic study
No full text
INVESTIGATING THE IMPACT OF ROAD NETWORK DEVELOPMENT ON LAND COVER CHANGE IN LIJIANG RIVER BASIN
No full textLijiang River Basin (LRB) has witnessed intensive human activities in the past 20 years, due to its unique karst landform, which has attracted a large amount of tourists. During this period, land cover changes were impacted by rapid expansion of road network substantially. This paper analyzes the interactions between road network and land cover change in the LRB by statistical analysis on both random samples and buffer samples. The results demonstrate that road network has a positive correlation with built-up land area and a negative correlation with woodland area. Built-up land is more affected by road network as compared with woodland. Impact strength of surface distance to road on built-up land is greater than that on woodland. Random samples and buffer samples in combination help us uncover the interactions between road networks and land cover change quantitatively and thoroughly.Engineering, Electrical & ElectronicGeosciences, MultidisciplinaryRemote SensingEICPCI-S(ISTP)
Experimental Study of the Effect of Excavation on Existing Loaded Piles
No full textExcavation beneath an existing building to add a new basement is an effective mean to expand underground space that caters to the increased need of space in urban areas. Because piles serve as load-bearing structures in high-rise buildings, excavation inevitably changes the bearing capacity of the existing piles and affects the safety of aboveground structures. This paper presents a series of experimental tests in a calibration chamber designed to clarify the effect of excavation on the performance of existing loaded piles. Excavation tests as well as pile load tests at the ground level and at the formation level of excavation were involved in capturing the effect of excavation on the capacity, stiffness, and load transfer of loaded piles. Test results showed that the reduction of pile capacity due to excavation is proportional to the magnitude of confinement of the area to be excavated. Constructing a new basement beneath an existing basement may result in a larger reduction of pile capacity when comparing that conducted at the ground surface. Unlike the nonloaded pile subjected to excavation, tensile force is not observed along the loaded pile shaft in the present test series. The results also indicated that the stress relief induced by excavation may be instrumental in the stiffness efficiency of the pile group
A multi-horizon peridynamics for coupled fluid flow and heat transfer
No full textThis paper presents a peridynamics-based computational approach for modelling coupled fluid flow and heat transfer problems. A new thermo-hydrodynamic peridynamics model is formulated with the semi-Lagrangian scheme and non-local operators. To enhance accuracy and numerical stability, a multi-horizon scheme is developed to introduce distinct horizons for the flow field and thermal field. The multi-horizon scheme helps to capture the convective zone and complex thermal flow pattern while effectively mitigating possible oscillations in temperature. We validate the computational approach using benchmarks and numerical examples including heat conduction, natural convection in a closed cavity, and Rayleigh–Bénard convection cells. The results demonstrate that the proposed method can accurately capture typical thermal flow behaviours and complex convective patterns. This work offers a new foundation for future development of a unified peridynamics framework for robust, comprehensive multi-physics analysis of thermal fluid–solid interaction problems with complex evolving discontinuities in solids.</p
