Coulomb-coupled quantum-dot thermal transistors

A quantum-dot thermal transistor consisting of three Coulomb-coupled quantum dots coupled to respective electronic reservoirs by tunnel contacts is established. The heat flows through the collector and emitter can be controlled by the temperature of the base. It is found that a small change in the base heat flow can induce a large heat flow change in the collector and emitter. The huge amplification factor can be obtained by optimizing the Coulomb interaction between the collector and the emitter or by decreasing the energy-dependent tunneling rate at the base. The proposed quantum-dot thermal transistor may open up potential applications in low-temperature solid-state thermal circuits at the nanoscale.Comment: 14 pages, 6 figure

International oil price’s impacts on carbon emission in China’s transportation industry

Purpose: This paper analyses the impact mechanism of international oil price on the industrial carbon emission, and uses the partial least squares regression model to study international oil price’s impact on carbon emissions in China’s transportation industry. Design/methodology/approach: This paper chooses five independent variables of GDP, international oil price, private car population, passenger and freight transportation volume as impact factors to investigate industrial carbon emissions, the paper also analyses the impact mechanism of international oil price on the industrial carbon emission, and finally the paper uses the partial least squares regression model to study international oil price’s impact on carbon emissions in China’s transportation industry. With the independent variables’ historical data from 1994 to 2009 as a sample, the fitting of the industry carbon emissions is satisfying. And based on the data of 2011, the paper maintains the private car owning, passenger and freight transportation volume to study international oil prices’ impact on the industry carbon emissions at different levels of GDP. Findings: The results show that: with the same GDP growth, the industry carbon emissions increase with the rise in international oil prices, and vice versa, the industry carbon emissions decrease; and lastly when GDP increases to a certain extent, in both cases of international oil prices’ rise or fall, the industry carbon emissions will go up, and the industry carbon emissions increase even faster while the energy prices are rising. Practical implications: Limit the growth in private-vehicle ownership, change China's transport sector within the next short-term in the structure of energy consumption and put forward China's new energy, alternative energy sources and renewable energy application so as to weaken the dependence on international oil, and indirectly slowdown China's GDP growth rate, which are all possible solutions to reduce China's transportation industry carbon emission. Originality/value: The paper presents a method to study international oil prices’ impact on the industry carbon emissions at different levels of GDP; and draws some corresponding proposals on industry carbon emission reductionPeer Reviewe

An Improved Optimal Slip Ratio Prediction considering Tyre Inflation Pressure Changes

The prediction of optimal slip ratio is crucial to vehicle control systems. Many studies have verified there is a definitive impact of tyre pressure change on the optimal slip ratio. However, the existing method of optimal slip ratio prediction has not taken into account the influence of tyre pressure changes. By introducing a second-order factor, an improved optimal slip ratio prediction considering tyre inflation pressure is proposed in this paper. In order to verify and evaluate the performance of the improved prediction, a cosimulation platform is developed by using MATLAB/Simulink and CarSim software packages, achieving a comprehensive simulation study of vehicle braking performance cooperated with an ABS controller. The simulation results show that the braking distances and braking time under different tyre pressures and initial braking speeds are effectively shortened with the improved prediction of optimal slip ratio. When the tyre pressure is slightly lower than the nominal pressure, the difference of braking performances between original optimal slip ratio and improved optimal slip ratio is the most obvious

Dynamic Characteristic Analysis of Indirect Carbon Emissions Caused by Chinese Urban and Rural Residential Consumption Based on Time Series Input-Output Tables from 2002 to 2011

Carbon emissions caused by residential consumption have become one of the main sources of carbon emission and revealed a huge growth trend in China. By processing data of Chinese input-output tables available and relative Statistical Yearbook, this paper uses RAS method to update the input-output tables to obtain the time series input-output tables from 2002 to 2011. Then, we use input-output method to make a contrastive analysis of changes in carbon emissions caused by Chinese rural and urban residents’ consumption. The results show that the indirect carbon emission caused by urban residents’ consumption is the main part of carbon emission caused by residents’ consumption, and the gap between carbon emission caused by urban and rural residents’ consumption is wider and wider. The annual per capita indirect carbon emissions in urban and rural areas increase by years, and the increment of the town is much greater than that of the country. At last, we analyze carbon emissions from residents’ consumption by sectors and obtain some meaningful results. In accordance with the above conclusions, the paper puts forward some countermeasures and suggestions from consumer behaviors, structure of consumption, energy usage, and so on