Structural, Electronic and Optical Characteristics of HgSiX2 (X=P, As) Chalcopyrite Materials: A DFT-Based Computer Simulation

Khalid Shah,Khenata Rabah,Ma Yue,Sun Xiaoliang,Gao Meng,Wu Haicheng,Lu Guiwu,Yang Zhenqing 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.1

In the present work, we determined the structural, electronic and optical properties of HgSiX2 (X = P, As) chalcopyrite materials by using the density functional theory (DFT). Our calculated results showed alignment with the data drawn from other experimental and theoretical studies. Therefore including the lattice parameters, bulk moduli, band gaps, the total and partial densities of states and the optical properties. The computed band structures and density of states (DOS) disclosed that HgSiP2 and HgSiAs2 are semiconductors materials with energy gaps equal to 0.931 eV and 0.425 eV, respectively. Our findings displace that the Si-3p, P-3p and As-4p atomic orbitals contribute to the density of states. Moreover, a comprehensive analysis of the electronic and the optical properties such as the reflectivity, absorption spectra, and dielectric functions revealed that the HgSiP2 and the HgSiAs2 materials may be beneficial in optoelectronic applications. We hope that the designs and preparations of the HgSiP2 and the HgSiAs2 materials will lead to give new advance strategies and gateways for the explorations of highly efficient optoelectronic devices.

HYPERPARAMETERS OF Q-LEARNING ALGORITHM ADAPTING TO THE DRIVING CYCLE BASED ON KL DRIVING CYCLE RECOGNITION

Yanli Yin,Xuejiang Huang,Xiaoliang Pan,Sen Zhan,Yongjuan Ma,Xinxin Zhang 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.4

As an effective reinforcement learning (RL) algorithm, Q-learning has been applied to energy management strategy of hybrid electric vehicle (HEV) in recent years. In the existing literatures, the values of three hyperparameters based on Q-learning are all given in advance, which are respectively exploratory rate ε, discount factor γ and learning rate α. However, different values of hyperparameters will influence on fuel economy of the vehicle and offline computation speed. In this paper, it is proposed that the method of optimization on hyperparameters adapting to driving cycle. Firstly, the mathematical model between three hyperparameters and iteration times is established based on inherent regularity of hyperparameters influencing on vehicle performance respectively. Secondly, it is determined that the optimal changing index k_index of iteration number based on Q-learning corresponding to typical driving cycles. Finally, the simulation model of Yubei District in Chongqing is constructed based on the method of Kullback-Leibler (KL) driving cycle identification. The simulation results indicate that equivalent fuel consumption of the proposed strategy is reduced by 0.4 % and the offline operation time is reduced by 6 s. It can be concluded that the proposed strategy can not only improve fuel economy of the vehicle, but also accelerate the computation speed

Distribution characteristics and processes along flow paths of shallow groundwater in the Tan-Lu fault zone in Anhui province, China

Dejian Wang,Jiazhong Qian,Weidong Zhao,Xiaoliang Hou,Wei Wang,Lei Ma 한국지질과학협의회 2022 Geosciences Journal Vol.26 No.4

To disclose the distribution characteristics, the situation of flow and storage, and processes along flow paths of shallow groundwater in Tan-Lu fault zones, nine hundred and seven groundwater table elevations data and one hundred hydrochemical samples of shallow groundwater were taken from the Tan-Lu fault zone in Anhui province to analyze the characteristic of groundwater distribution. The geographic information system (GIS) method was used to analyze the spatial distribution characteristics of groundwater tables, total dissolved solids (TDS) and chloride ion (Cl−). Geophysical prospecting, drilling material and regional hydrogeological survey were utilized to disclose groundwater storage and flow regime in the fault zone. The results show that the Tan-Lu fault zone in Anhui province has controlled groundwater flow into the Jiashan basin, Hefei basin, Chaohu area and Qianshan basin, which developed from north to south in this area. Groundwater in theses basins have recharged from surrounding areas to form a water storage space. Geophysical prospecting and drilling technology revealed that the Tan-Lu fault zone provided a flow channel and storage space for groundwater. Faults provide preferential channels in some areas for the groundwater flow and circulation, eventually deep hot-water flows upward and discharges in the form of hot-springs. The identification of the groundwater flow pathway can help to provide a reliable scientific basis for regional spatial development and utilization of groundwater resources.

Purification of pickling wastewater from the steel industry using membrane filters: Performance and membrane fouling

Jinfeng Zhang,Guanyi Chen,Yanning Ma,Miao Xu,Songyan Qin,Xiaoliang Liu,Haijun Feng,Lian Hou 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.1

A new technique for treating pickling wastewater discharged from the steel industry using membrane filters was developed and membrane fouling was characterized in a full scale membrane filter. The morphological and chemical properties were examined through scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma optical emission spectroscopy (ICP-OES) etc. The results showed that inorganic elements such as phosphates, chlorides, and sulfates were severely blocked in membrane surfaces and pores. The porosity, permeability, hydrophilic contact angle, and surface charge capacity of fouled membranes were all lower than those of new membranes, while the optimal neutralization reaction pH region for fouled membranes shifted and narrowed. Charge neutralization is a critical reason to membrane fouling. By increasing the Zeta potential of the pickling wastewater, the membrane fouling could be controlled. This method is proven to effectively improve the separation property of precipitates after pickling wastewater was neutralized. Moreover, Neutralization helped to reduce the unit number of treatment processes. This investigation could assist in obtaining a better understanding of the fouling properties and behavior in the full-scale membrane filters in the pickling wastewater treatment.

Behaviors of metal compounds during hydrodemetallization of atmospheric residue

박주일,Adel Al-Mutairi,Abdulazeem M.J. Marafie,Isao Mochida,윤성호,Xiaoliang Ma 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.40 No.-

Behaviors of vanadium and nickel species during hydrodemetallization (HDM) were studied. A Kuwaitatmospheric residue and its hydrodemetallized products from a pilot plant at mild and severe reactionconditions were characterized by using GPC coupled with ICP-MS and high temperature GC-AED afterseparation of them into saturates, aromatics, resins, and asphaltenes. It was found that the HDMreactivity of the vanadium species, especially those with lower molecular weight, was higher than that ofNi species, probably due to the higher polarity of the former than the latter. HDM of the vanadiumspecies in the asphaltene was more difficult than that in the resin. The average molecular weight of metalspecies through higher temperature HDM was higher than that through the lower temperature HDM,although the metal removal at the higher temperature is higher.

The characterization of metal complexes in typical Kuwait atmospheric residues using both GPC coupled with ICP–MS and HT GC–AED

박주일,Adel Al-Mutairi,Abdulazeem M.J. Marafie,윤성호,Isao Mochida,Xiaoliang Ma 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.34 No.-

The aim of this study is to characterize the vanadium and nickel species in saturate, aromatic, resin andasphaltene fractions from typical Kuwait atmospheric residues, using GPC coupled with an ICP–MS andHT GC–AED. It was found that most of vanadium and nickel complexes were in both resin and asphaltenefractions, while there was very small amount of non-porphyrinic metal species in the aromatic fractions. The nickel complexes show higher molecular weight than that of the vanadium complexes. Theporphyrin units existing in the asphaltenes linked to the larger aggregates, while in the resins associatedwith less aggregates.