Design and parameter optimization of high-power coupling mechanisms

Xueli Liu,Hang Meng,Yang Li,Suya Kou,Zhanglei An,Chong Zhang 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.3

To ensure the efficient operation of high-power (30 kw) wireless power transmission, this paper proposes a parallel doublelayer rectangular coil with rounded corners that improves the transmission effi ciency through parameter optimization. Finally, an experimental platform is established to verify the accuracy of the parameter optimization. The transmission efficiency of the optimized coil is increased from 82.5 to 91.3% when the transmission distance is 150 mm, and the transmission efficiency is increased by 15.8% and 30% when the unidirectional and bidirectional offset distances are 100 mm, respectively. In addition, two shielding methods, expanding shielding and vertical shielding, are proposed. Experimental results show that these two shielding methods can effectively reduce the edge effect of the traditional shielding structure and improve the transmission characteristics and electromagnetic safety.

Application of molecular dynamics simulation in self-assembled cancer nanomedicine

Xueli Xu,Ao Liu,Shuangqing Liu,Yanling Ma,Xinyu Zhang,Meng Zhang,Jinhua Zhao,Shuo Sun,Xiao Sun 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Self-assembled nanomedicine holds great potential in cancer theragnostic. The structures and dynamics of nanomedicine can be affected by a variety of non-covalent interactions, so it is essential to ensure the self-assembly process at atomic level. Molecular dynamics (MD) simulation is a key technology to link microcosm and macroscale. Along with the rapid development of computational power and simulation methods, scientists could simulate the specific process of intermolecular interactions. Thus, some experimental observations could be explained at microscopic level and the nanomedicine synthesis process would have traces to follow. This review not only outlines the concept, basic principle, and the parameter setting of MD simulation, but also highlights the recent progress in MD simulation for self-assembled cancer nanomedicine. In addition, the physicochemical parameters of self-assembly structure and interaction between various assembled molecules under MD simulation are also discussed. Therefore, this review will help advanced and novice researchers to quickly zoom in on fundamental information and gather some thoughtprovoking ideas to advance this subfield of self-assembled cancer nanomedicine.

Facile Preparation and Characterization of Graphene Nanosheets/Polystyrene Composites

Xueli Wu,Peng Liu 한국고분자학회 2010 Macromolecular Research Vol.18 No.10

Graphene nanosheets/polystyrene (GNS/PS) composites were prepared by in-situ free radical solution polymerization. The graphene nanosheets were dispersed well in the polymer matrices due to the covalent interface between the inorganic and polymer phases. The effect of the amount of the initiator added on the thermal stability and electrical conductivity of the composites were compared. Thermogravimetric analysis (TGA) and gel permeation chromatography (GPC) analyses of the polystyrene grafted graphene nanosheets (GNS-PS) samples showed that more polystyrene chains with a relatively smaller molecular weight had been grafted onto the graphene nanosheets via free radical addition with more initiator added to the solution polymerization.

A theoretical investigation on ESIPT process of a red-emitting ratiometric fluorescent probe and its fluorescent detection mechanism for cyanide anion

Xueli Jia,Yufang Liu 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.99 No.-

Excited state intramolecular proton transfer (ESIPT) process of afluorescent probe (EP1) and itsfluorescent detection mechanism for cyanide anion (CN ) have been investigated theoretically. Optimized structures indicate that the hydrogen bond (O1 H2 O3) in EP1 is strengthened upon photo-excitation and the O1 H2 proton in EP1-CN formed after adding CN transfers spontaneously to O3. Potential energy curves confirm that proton transfer in EP1 is impossible because energies of the S0 and S1states increase with the O1 H2 bond length. While proton transfer in EP1-CN is unobstructed becauseenergies of the S0 state decrease with the O1 H2 bond length. Compared to EP1, the absorption andfluorescence spectra of EP1-CN are both red-shifted (87 and 41 nm) due to the large charge transferextent. Orbital-weighted dual descriptor isosurface and condensed local nucleophilicity indices confirmthat the carbon atom on the aldehyde group is the nucleophilic site of CN . Transition state searchingdemonstrates that the occurrence of nucleophilic addition reaction between EP1 and CN shouldovercome a reaction barrier of 14.29 kcal/mol and then get EP1-CN, which has 6.61 kcal/mol lower energythan reactants. Thus, EP1 detecting CN is through thefluorescence variation induced by the large chargetransfer extent rather than by hampering ESIPT.

Toughening of melamine–formaldehyde foams and advanced applications based on functional design

Bing Song,Xueli Zhu,Wei Wang,Liang Wang,Xiaoyuan Pei,Xiaoming Qian,Liangsen Liu,Zhiwei Xu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.119 No.-

Owing to the intrinsic flame-retardancy, thermal stability, sound absorption, and easy processing, melamine–formaldehyde foams(MFs) have drawn substantial attention. Typically, the high-porosity and compressibilityof flexible MFs render them suitable for the construction of 3D templates and in thefabrication of porous N-doped carbon materials. But the widespread applications of MFs still suffer highbrittleness and low strength, calling for modifying and toughening MFs with more facile and economicalmethods, and much potential in advanced applications by functional design deserves further exploration. This review comprehensively summarized and evaluated the recent progress of the toughening methodsof MFs. We will also look into the applications of commercial MFs, carbonized MFs and foam-based compositesin flame retardancy and thermal management, oil/water separation, photothermal conversion,electrical energy storage, and other fields, aiming to give a guide for the preparation, modification, andexploitation of MFs both in traditional and emerging areas.

ENTROPY OF NONAUTONOMOUS DYNAMICAL SYSTEMS

Zhu, Yujun,Liu, Zhaofeng,Xu, Xueli,Zhang, Wenda Korean Mathematical Society 2012 대한수학회지 Vol.49 No.1

In this paper, the topological entropy and measure-theoretic entropy for nonautonomous dynamical systems are studied. Some properties of these entropies are given and the relation between them is discussed. Moreover, the bounds of them for several particular nonautonomous systems, such as affine transformations on metrizable groups (especially on the torus) and smooth maps on Riemannian manifolds, are obtained.

Entropy of nonautonomous dynamical systems

Yujun Zhu,Zhaofeng Liu,Xueli Xu,Wenda Zhang 대한수학회 2012 대한수학회지 Vol.49 No.1

In this paper, the topological entropy and measure-theoretic entropy for nonautonomous dynamical systems are studied. Some properties of these entropies are given and the relation between them is discussed. Moreover, the bounds of them for several particular nonautonomous systems, such as affine transformations on metrizable groups (especially on the torus) and smooth maps on Riemannian manifolds, are obtained.

Gas-phase dehydration of glycerol to acrolein over different metal phosphate catalysts

Tianlin Ma,Jianfei Ding,Xueli Liu,Gangling Chen,Jiandong Zheng 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.6

We conducted a comparative study of gas phase dehydration of glycerol to acrolein over aluminium phosphate, iron phosphate and nickel phosphate catalysts prepared by a simple replacement reaction method (AlP, FeP and NiP). The textural properties, acid amounts, acid types, and coke contents of the samples were studied. The results showed that all metal phosphate catalysts remained in an amorphous state. The glycerol conversion was proportional to the acid amount of metal phosphate catalyst in the glycerol dehydration reaction. Higher value of B/L was more likely to produce acrolein. Among the metal phosphate catalysts, FeP showed superior performance due to its suitable textural and acid properties. After 2 h on stream, high glycerol conversion (96%), acrolein selectivity (82%) and acrolein yield (79%) were achieved on the FeP catalyst at 280 oC. The catalyst deactivation was ascribed to carbon deposition on the catalyst surface blocking the active sites during the glycerol dehydration reaction.

3D Printing of Bioinspired Structural Materials with Fibers Induced by Doctor Blading Process

Luquan Ren,Bingqian Li,Zhengyi Song,Qingping Liu,Lei Ren,Xueli Zhou 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.6 No.1

Fiber is a crucial element in biological micro-structural materials. Replication of fiber-reinforced composites with analogous architectures of their natural counterparts has caused widespread academic concern. Recent researches indicate 3D printing technology has the potential to produce biomimetic structural materials. The aim of this study is to develop a process to fabricate fiber-reinforced composites with ordered yet spatially tunable fiber arrangement. Specifically, we present a method to align fibers during the 3D printing of fiber-reinforced composites. A modified slurry-based stereolithography process was developed, and the fibers in the fiber–resin mixture were aligned by Shear force produced during the spreading of slurry. We investigated the influence of relative factors on fiber orientation, and two models were used to uncover the internal mechanism. By controlling the speed and the direction of the moving blade, the patterns that fibers were arranged can be freely programmed. Therefore, we have extracted bioinspired sinusoidal and zigzag design motifs to analyze their mechanical properties compared with non-bioinspired motifs. The proposed method is relatively material agnostic, more efficient and more facile. It thus provides a promising route to fabricate fiber-reinforced composites, and has potential to be adopted in biological structures researches and industrial applications.

Effects of KBrO3 on Chemical, Aggregation and Morphological Structure of Polyacrylonitrile (PAN) Precursor Fibers

Yatian Chen,Bin He,Qiufei Chen,Hamza Malik,Hongqiang Zhu,Yuhang Wang,Jian He,Bomou Ma,Xueli Wang,Hui Zhang,Yong Liu 한국섬유공학회 2023 Fibers and polymers Vol.24 No.9

The effects of KBrO3 modification on polyacrylonitrile (PAN) precursor fibers at different modification temperatures were studied. The mechanical properties, chemical structure, aggregation structure, morphological structure, and thermal behavior of PAN precursor fibers were analyzed. The mechanical properties of PAN precursor fibers are essentially unaltered after KBrO3 modification, although oxygen-containing functional groups are introduced. KBrO3 can ionize bromate ion in aqueous solution, which has good nucleophilicity and can attack the positively charged carbon atom in C≡N, so that the cyclization proceeds according to the ionic mechanism, allowing the transformation of C≡N to C = N in the PAN precursor fibers generated a cyclic trapezoidal structure containing primary aromatic amine, which reduced the peak temperature of the cyclization reaction from 284.5 °C to 275.1 °C and decreased the heat release. The sp3-hybridized carbon structure changes into a sp2 hybridized C = C structure with increasing aromatization, according to XRD and Raman data, and the KBrO3 alteration accelerates the degradation of the original microcrystalline structure and transforms into a new polycyclic aromatic structure. The degree of conjugation and aromatization of the system rapidly increased with the rise in modification temperature. The stabilized fibers were discovered to have the lowest R-value, the highest aromatization, the smoothest surface, and the fewest flaws at impregnation temperature of 60 °C.