Assessing China’s regional efficiency of energy-saving and emission reduction using the target orientation approach of extended DDF model

Based on the target of energy-saving and emission reduction(ESER)in the national five-year plan in China,an extended directional distance function model(E-DDF)including undesirable input and undesirable output is proposed,and energy-saving efficiency,emission reduction efficiency,ESER efficiency are defined.Then the weighted directional distance function model is constructed for the total factors efficiency index model of ESER to reflect its dynamic change.The results show that the ESER efficiency continues to rise during the three five-year plan periods(2006-2017),and the efficiency score of the east area are higher than those of central and west area.The disparity and change of energy-saving efficiency among difference regions are not obvious,but the disparity and change of emission reduction efficiency are the main reasons for the improvement and change of ESER efficiency index.In the long run,the ESER efficiency is in a dynamic upward trend,and the effect of technological progress is more obvious compared with technical efficient index.

A Study on the Kinetics of the Europium Electrochemistry Reduction (Ⅱ)——The Europium Electroreduction Kinetic Properties

This article studied the europium electroreduction kinetic properties in the Sm-Eu-Gd chloride system by using an electrolytic cell with membrane and constant potential method.The results indicate that within the parameter range of this study the europium reduction speed up with the increase of the system's temperature,the stirring intensity,feed concentration and the cathod area,and with the decrease of the cathodic potential.As the feed acidity increases,the reduction rate decreases.An empirical formula for europium's electroreduction kinetics in this experimental condition is also given.

A Comparative Assessment of On-Site Application Effects of Mine Dust Prevention and Control Technology

Prolonged exposure to coal dust leads to various lung disorders, including incurable coal workers’ pneumoconiosis (CWP), and endangers miners’ health in underground mines. This article summarizes the latest research progress in dust control technology, including chemical dust suppressants, foam dust removal, ultrasonic atomization, magnetized water dust suppression, double curtains of wind and fog, biological nano-film, and emerging microbial dust suppressants in the field of dust. The actual application compares and analyzes the advantages and disadvantages of different dust removal technologies. The current three directions of mine dust prevention and control are pointed out: the prevention and control of respirable dust, hydrophobic dust, and secondary dust, and the prospects for future development trends. Given the treatment of respirable dust, it is necessary to strengthen the research on the dust generation mechanism under different working conditions and to explore the migration and settlement laws of respirable dust by constructing a numerical model of dust dynamics;for the treatment of hydrophobic dust, further research on the microphysical and chemical properties of coal dust is needed. The relationship between wettability and continuously optimizing the wetting agent;for the prevention and control of secondary dust in coal mines, emerging microbial dust suppression technologies need to be developed to explore the micro-action between microorganisms and coal dust molecules to achieve green prevention and control of dust.

Nb_2O_5 nanowires in-situ grown on carbon fiber: A high-efficiency material for the photocatalytic reduction of Cr(Ⅵ)

Niobium oxide nanowire-deposited carbon fiber（CF） samples were prepared using a hydrothermal method with amorphous Nb2O5·nH2O as precursor. The physical properties of the samples were characterized by means of numerous techniques, including X-ray diffraction（XRD）, energy-dispersive spectroscopy（EDS）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, selected-area electron diffraction（SAED）, UV–visible spectroscopy（UV–vis）, N2 adsorption–desorption, Fourier transform infrared spectroscopy（FT-IR）, and X-ray photoelectron spectroscopy. The efficiency for the removal of Cr（VI） was determined.Parameters such as pH value and initial Cr（VI） concentration could influence the Cr（VI） removal efficiency or adsorption capacity of the Nb2O5/carbon fiber sample obtained after hydrothermal treatment at 160°C for 14 hr. The maximal Cr（VI） adsorption capacity of the Nb2O5 nanowire/CF sample was 115 mg/g. This Nb2O5/CF sample also showed excellent photocatalytic activity and stability for the reduction of Cr（Ⅵ） under UV-light irradiation： the Cr（VI） removal efficiency reached 99.9% after UV-light irradiation for 1 hr and there was no significant decrease in photocatalytic performance after the use of the sample for 10 repeated cycles. Such excellent Cr（VI） adsorption capacity and photocatalytic performance was related to its high surface area,abundant surface hydroxyl groups, and good UV-light absorption ability.

Experimental study of the anode injection efficiency reduction of 3.3-kV-class NPT-IGBTs due to backside processes

The anode injection efficiency reduction of 3.3-kV-class non-punch-through insulated-gate bipolar transistors （NPT-IGBTs） due to backside processes is experimentally studied through comparing the forward blocking capabilities of the experiments and the theoretical breakdown model in this paper.Wafer lifetimes are measured by aμ-PCD method,and well designed NPT-IGBTs with a final wafer thickness of 500μm are fabricated.The test results show higher breakdown voltages than the theoretical breakdown model in which anode injection efficiency reduction is not considered.This indicates that anode injection efficiency reduction must be considered in the breakdown model.Furthermore,the parameters related to anode injection efficiency reduction are estimated according to the experimental data.

Effect of Soil Fertilizer Application on Soil Nutrient Migration and Tea Quality of Plateau-Puerh Tea

In order to solve the problem of chemical fertilizer application balance of Pu’er tea in Taiwan, the effects of different fertilization treatments on land nutrient migration and tea quality were explored, and the basis for rational fertilization of tea gardens was provided. In this study, the effects of different fertilization treatments on tea quality indexes were studied by three different sets of fertilization treatments in tea gardens. Three sets of different fertilization treatments were set up in the experiment: conventional fertilization treatment (T1), slow-release fertilizer reduction by 20% (T2) and slow-release fertilizer reduction by 30% (T3), and the quality index of tea under different fertilization treatments, as well as the alkaline nitrogen, available phosphorus and total nitrogen and total phosphorus content in surface water of the soil were measured and analyzed. The results showed that: 1) compared with T1, the soil available phosphorus in T3 decreased by 23.5%, and the alkalinelyzed nitrogen increased by 20.5%;2) compared with T1, the total nitrogen and total phosphorus concentrations of surface water in the T2 and T3 treatments were at a low level compared with T1;compared with T1, T2 decreased by 71.4%, and T3 decreased by 68.6%;3) compared with T1, T3 was able to maintain the quality indicators of amino acids, tea polyphenols and soluble sugars in tea in a high and stable range. Therefore, under the condition of conventional fertilization and reduction, a 30% reduction in slow-release fertilizer is currently more suitable for the fertilization technology of Menghai County Tea Garden.