Preparation and photocatalytic properties of porous C and N co-doped TiO_2 deposited on brick by a fast, one-step microwave irradiation method

A one-step microwave irradiation method was used to deposit carbon and nitrogen co-doped TiO2（（C, N）-TiO2） on commercial brick（（C, N）-TiO2/brick）. The as-prepared samples were characterized by X-ray diffraction, ultraviolet–visible（UV–vis） diffuse reflectance spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy（SEM）. A selective technique was also used to investigate the concentration of hydroxyl radicals during UV–vis irradiation of the Methyl Orange solution with the as-prepared samples. The C and N dopants enhanced visible light absorption and provided a longer lifetime for the photo-generated electron–hole pairs. The SEM images showed that the as-prepared sample is porous. The dark adsorption and photodegradation test for（C, N）-TiO2/brick showed good photodegradation and good recyclability. The best photodegradation rate was 94% after 2 hr. The maximum degradation rate was maintained even after the 6th cycle. The good photocatalytic properties are attributed to the enhanced visible light absorption, enhanced pollutant adsorption arising from the porous structure of the（C, N）-TiO2 thin film, and longer lifetime of the photo-generated electron–hole pairs.（C, N）-TiO2/brick should have potential commercial applications in photodegradation processes because of its low cost, good photodegradation, and excellent recyclability.

Decomposition and decoupling analysis of electricity consumption carbon emissions in China

Electricity consumption is one of the major contributors to greenhouse gas emissions.In this study,we build a power consumption carbon emission measurement model based on the operating margin factor.We use the decomposition and decoupling technology of logarithmic mean Divisia index method to quantify six effects(emission intensity,power generation structure,consumption electricity intensity,economic scale,population structure,and population scale)and comprehensively reflect the degree of dependence of electricity consumption carbon emissions on China's economic development and population changes.Moreover,we utilize the decoupling model to analyze the decoupling state between carbon emissions and economic growth and identify corresponding energy efficiency policies.The results of this study provide a new perspective to understand carbon emission reduction potentials in the electricity use of China.

Pseudo-active actuators:A concept analysis

The superior performance of active vibration control systems largely depends on the four-quadrant controllable execution capability in the available force-velocity diagram of active actuators.Although semi-active vibration control systems have the advantages of low energy consumption,simple structure,and high reliability,the system performance is not comparable to active control systems,due to the partial capability in only the first and third quadrants.On the basis of the comprehensive advantages of active and semi-active actuators,to reform the design philosophy of semi-active actuators to realize pseudo-active actuators that have both mechanical properties of active actuators and energy consumption advantages of semi-active actuators,that is,new semi-active actuators with four-quadrant controllable execution capability,will very likely cause a revolution in the related fields of mechanical design and system control.The basic design principle of pseudo-active actuators that use semi-active controllable actuators to achieve active actuator performance in the way of conceptual analysis is proposed.The proposed pseudo-active actuators should consist of two half-four-quadrant actuators,that is,one is for the first and third quadrants and the other one for the second and fourth quadrants.This study employs two semi-active controllable damping actuators and one mechanical compensation mechanism.One of the actuators provides the damping force in the first and third quadrants,and the other one combining with the mechanical compensation mechanism is for the second and fourth quadrants.A global mathematical model of the proposed actuator is established to describe the four different operational modes of the proposed actuator.It is proved that the two operational modes of the proposed actuator can realize active vibration control,and a case study of realizing active control is presented.The other two operational modes are compared with the conventional two-degree-of-freedom model.More specifically,the application cases of the pseudo-active operational mode of the proposed actuator in the quarter-car/body-powertrain suspension system are given,a pseudo-active suspension named dual-hook automobile suspension is presented.Furthermore,an equivalent expression of the electrical network is given for the mechanical network under different operational modes of the proposed actuator.