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Wenyuan Wang,Yali Feng,Haoran Li,ShunLiang Liu,Jinrong Ju,Yi Yang,Ben Wang 대한환경공학회 2023 Environmental Engineering Research Vol.29 No.3
Chemical waste salt is a hazardous waste generated during chemical production, and it is crucial to complete the recycling of the waste salt in a practical way. In the case of waste salt recycling by rotary kiln pyrolysis carbonization, ringing affects the pyrolysis efficiency and process running, thus a study on waste salt ringing was conducted. The results showed that the particle size is the key to the ring formation in rotary kiln, and pyrolysis temperature, pyrolysis time and temperature distribution in the rotary kiln also affect the material discharge rate during pyrolysis of waste salt in the rotary kiln. Thermogravimetric analysis and SEM images revealed that the volatilization of organic matter in the material due to pyrolysis caused a decrease in the abrasion resistance of the waste salt particle, which was the factor behind the ringing during pyrolysis in the rotary kiln. This study may provide a reference for the implementation of similar waste salt pyrolysis carbonization processes.
Qinghua Wang,Wei Wang,Junlin Huang,Hong Yin,Yucan Zhu,Haitao Wang,Minjie Zhou,Binhong He,Zhaohui Hou,Wenyuan Xu 한국탄소학회 2023 Carbon Letters Vol.33 No.1
Transition-metal phosphides (TMPs), a promising anode material for lithium-ion batteries (LIBs), are limited in application because of its serious volume effect in the cycle. In this work, a simple electrospinning strategy was proposed to restrict the grain size of CoP nanocrystals by nano-confined effect of carbon nanofibers with ligands. The addition of ligands not only could realize the uniform dispersion of CoP nanocrystals, but also strengthen the bond between the metals and carbon nanofibers. As a result, the CoP/CNF composite exhibits excellent lithium storage performance, and its reversible specific capacity could reach 1016.4 mAh g? 1 after 200 cycles at a current density of 200 mA g? 1. The research is anticipated to provide a new idea for the preparation of anode materials for lithium ion batteries.
Jun Wang,Hao Song,Xuzhao Yang,Wenyuan Zou,Yufei Chen,Shaochan Duan 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.8
The density, viscosity, and refractive index of a pure asymmetrical dicationic ionic liquid, 1-(1-methypiperidinium- 1-yl) pentane-(1-pyridinium) bis(trifluoromethane)sulfonamide, and its binary mixtures with acetonitrile were investigated at temperatures from 293.15 K to 323.15 K over the entire range of composition at ambient pressure. From the experimental data, the excess molar volumes, dynamic viscosity deviations, and refractive index deviations were, respectively,calculated and correlated with Redlich-Kister-type polynomials. The temperature dependence of viscosity for pure ionic liquid was described by modified Vogel-Tammann-Fulcher (VTF) equation. The enthalpy and entropy of activation for viscous flow were obtained. The values of molar refraction and polarizability indicated that the dominant interactions between ionic liquids and acetonitrile were dipole-dipole molecular interactions. These thermodynamic properties were discussed in terms of nature of molecular interactions between the ionic liquid and acetonitrile.
Behavior of Continuous Steel-concrete Composite Beams with Web Openings
Longqi Li,Wenyuan Liao,Jun Wang,Donghua Zhou 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.4
In order to investigate the mechanical performance and load carrying capacity of continuous steel-concrete composite beams with web openings, five continuous composite beams with web openings and a contrasting continuous composite beam without web openings were tested through two symmetric point loads. Nonlinear finite element analysis was also conducted, in which the slab thickness and the reinforcement ratio of slabs were selected as the major parameters. The main results of this test were concluded as follows: (1) Web openings not only decrease the stiffness and ultimate load carrying capacity of continuous composite beams but also give rise to the redistribution of vertical shear force between the cross section of the steel beam and the concrete slab at the web opening region. (2) The plane hypothesis is not satisfied at the web opening region. The failure mode of continuous composite beams with web openings is the shear failure of concrete slab in the region near the opening, and the result also indicates that the shear bearing capacity at the span with web openings become a critical factor in controlling design. (3) Meanwhile, by increasing the thickness and reinforcement ratio of a concrete slab, the ultimate load carrying capacity and ductility of continuous composite beams increased, which can be used to the enhancement of web opening region. (4) In addition, based on the experimental results, a finite element mode was established for composite beams with web openings, and good agreement was obtained between the tested results and the numerical results.
Liqun Xiao,Wenyuan Wang 한국통계학회 2017 Journal of the Korean Statistical Society Vol.46 No.3
A multiplicative regression model with longitudinal data is introduced, and a least product relative errors estimate is constructed based on relative errors. Generally, the least squares criterion and least absolute deviation criterion based on absolute errors are the most widely used criteria in the regression analysis. However, when response variables have different measurement scales, relative errors may be superior to absolute errors. Thence, we develop a least product relative errors estimator of parameter based on relative errors, and obtain their asymptotic properties where some nuisance parameters such as correlation structure of error terms are included. In addition, block empirical likelihood technique is employed to construct the confidence regions of the corresponding unknown regression parameter, avoiding density estimation. Simulation results confirm that the proposed methods perform well.
Qiang Zhang,Wenyuan He,Yinmin Wang,Dazhao Pei,Xue Jun Zheng 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.5
The sonication processing was added in front of the freeze-drying as an intermediate processing before the molybdenum disulfide (MoS2) aerogel was synthesized. It is distinguishing with the traditional hydrothermal reaction to combine the sonication processing and freeze-drying in our method. The structure, morphology, specific surface area and pore size distribution were characterized, and the electrochemical performances were measured in 0.5M Na2SO4 electrolyte for the MoS2 aerogel and flower-like MoS2. As for comparison, they are of porous structure and microsphere structure, and their specific surface areas are 55.14 m2 g -1 and 38.12 m2 g -1. The specific capacitances are 166.7 F g -1 and 119.2 F g -1 at the scan rate of 5 mV s -1, and the capacity retentions are 87.7% and 81.6% after 3000 charge/discharge cycles. For the enhanced mechanism, the high specific surface of the MoS2 aerogel causes high specific capacitance, and the unique porous structure could buffer volume expansion to improve retention ability during charge/discharge processes. The MoS2 aerogel may thus be a promising electrode material for supercapacitors.
( Ying Chen ),( Yangming Ge ),( Wenyuan Wang ),( Fengyu Yang ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.4
Heterogeneous wireless sensor networks (HEWSN) is a kind of wireless sensor networks (WSN), each sensor may has different attributes, HEWSN has been widely used in many aspects. Due to sensors are deployed in unattended environments and its resource constrained feature, the design of security and efficiency balanced authentication scheme for HEWSN becomes a vital challenge. In this paper, we propose a secure and lightweight user authentication and key agreement scheme based on biometric for HEWSN. Firstly, fuzzy extractor is adopted to handle the user’s biometric information. Secondly, we achieve mutual authentication and key agreement among three entities, which are user, gateway and cluster head in the four phases. Finally, formal security analysis shows that the proposed scheme defends against various security pitfalls. Additionally, comparison results with other surviving relevant schemes show that our scheme is more efficient in term of computational cost, communication cost and estimated time. Therefore, the proposed scheme is well suitable for practical application in HEWSN.
Theoretical Explanation of the Peak Splitting of Tobacco-Specific N-Nitrosamines in HPLC
Jiang, Juxing,Li, Liangchun,Wang, Mingfeng,Xia, Jianjun,Wang, Wenyuan,Xie, Xiaoguang Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.5
During the analyzing processes of the compounds, some researchers are puzzled by the analytical signals for some TSNAs (with or without splitting peaks at various pHs and temperatures). In this work, a detailed theoretical study of structural and thermal properties of the $E/Z$ isomers of TSNAs and the corresponding protonated structures was performed using DFT methods. The calculations showed that the $E$ isomers are almost stable than $Z$ isomers, while the $Z$ isomers would be more stable when in protonation. The calculated results predicted the possibility of separation of their $E$ and $Z$ isomer forms and also showed that protonation affects the dipole moment of molecules significantly (0.1-0.5 to 0.7-2.1 Debye). The calculations agreed well with the experiments that the split-up of the HPLC signal for TSNAs into two peaks are very sensitive to the pH and temperature of the mobile-phase.
Synthesis and thermodynamic properties of a novel pyridinium-based asymmetrical gemini ionic liquid
Xuzhao Yang,Jun Wang,Wenyuan Zou,Jinchao Wu 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.12
A novel asymmetrical gemini ionic liquid (GIL), [1-(1-pyridinium-yl-hexyl)-6-methylpiperidinium] dihexafluorophosphate ([PyC6MPi][PF6]2) combined with pyridine, 1-methylpiperidine by 1,6-dibromohexane with PF6 − as anion, was synthesized and characterized by 1H NMR and IR. The molar heat capacity of the GIL was measured via differential scanning calorimetry from 298.15 K to 448.15 K under atmospheric pressure. No phase transition or other thermal anomaly was observed in the solid-phase region (298.15 K to 358.15 K) and liquid-phase region (403.15 K to 448.15 K). The basic properties and thermodynamic functions of the GIL, such as melting point, molar enthalpy and entropy of fusion, heat capacity, enthalpy HT-H298.15 K, and entropy ST-S298.15 K, were also determined from the experimental data. Thermal decomposition kinetics of [PyC6MPi][PF6]2 were investigated by using non-isothermal thermogravimetric analysis in pure nitrogen atmosphere at various heating rates. Thermal decomposition data were, respectively, correlated with Friedman method, Ozawa-Flynn-Wall equation, and ASTM model. The activation energy (E) and pre-exponential factor (logA) values were obtained by using the above three methods.