Theoretical Prediction of Heat Transport in Few-Layer Graphene/ Epoxy Composites

Jianhua Zeng,Jiao Li,Peng Yuan,Ping Zhang 한국고분자학회 2018 Macromolecular Research Vol.26 No.11

Graphene is widely employed to improve the overall thermal conductivity of polymer composites because of its remarkable thermal conductivity. However, the magnitude of its improvement of thermal conductivity is far below the values expected from the remarkably high thermal conductivity of graphene and is very much less than the production cost of graphene, greatly limiting its large-scale applications in the field of thermal management. Therefore, understanding heat transport behaviors within the polymer composites and studying the related influential factors are very important. Here, heat transport behaviors within few-layer graphene (FLG)/epoxy composites are studied using molecular dynamics (MD) simulations. The influences of interfacial thermal resistance, FLG volume fraction and FLG length on overall thermal conductivity of the composites are specifically analyzed, finding that there is a significant interfacial thermal resistance between FLG and epoxy because of the mismatch of the phonon vibration power spectrum (VPS). Furthermore, the interfacial thermal resistance, FLG volume fraction, and FLG length play important roles in improving the overall thermal conductivity of FLG/epoxy composites. Our findings provide a better understanding of the heat transport behaviors within polymer composites and should be useful for future development of various thermal management applications.

Active Distribution System Planning for Low-carbon Objective using Cuckoo Search Algorithm

Zeng, Bo,Zhang, Jianhua,Zhang, Yuying,Yang, Xu,Dong, Jun,Liu, Wenxia The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.2

In this study, a method for the low-carbon active distribution system (ADS) planning is proposed. It takes into account the impacts of both network capacity and demand correlation to the renewable energy accommodation, and incorporates demand response (DR) as an available resource in the ADS planning. The problem is formulated as a mixed integer nonlinear programming model, whereby the optimal allocation of renewable energy sources and the design of DR contract (i.e. payment incentives and default penalties) are determined simultaneously, in order to achieve the minimization of total cost and $CO_2$ emissions subjected to the system constraints. The uncertainties that involved are also considered by using the scenario synthesis method with the improved Taguchi's orthogonal array testing for reducing information redundancy. A novel cuckoo search (CS) is applied for the planning optimization. The case study results confirm the effectiveness and superiority of the proposed method.

Influence mechanism of nano-SiO2 on water molecular diffusion at liquid-solid interface of natural ester and cellulose

Jianhua Chen,Zhenglin Zeng,Dong Huang,Chao Tang 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.123 No.-

It is necessary to study the micro mechanism of water diffusion behavior at the liquid-solid interfacebetween natural esters and cellulose by adding nanoparticles to natural esters, the unmodified andnano-SiO2 modified natural ester-cellulose mixing models were established by molecular simulationtechnology. The effects of nanoparticles on the moisture at the liquid-solid interface in the naturalester-cellulose insulation system were analyzed from the perspectives of relative concentration distribution,density field, interaction energy and hydrogen bonding. The simulation results show that watermolecules in natural ester tend to diffuse from natural ester to cellulose in all models, the binding effectof water molecules on cellulose in the nano-modified model is weakened, and the water peak in celluloseis reduced by 57% compared with the unmodified model, so that the moisture impurities in the nanomodifiedmodel cellulose are absorbed to the natural ester-cellulose interface, reducing the damage ofmoisture to the cellulose, which helps to improve the resistance of the natural ester-cellulose insulationcombination aging ability.

Active Distribution System Planning for Low-carbon Objective using Cuckoo Search Algorithm

Bo Zeng,Jianhua Zhang,Yuying Zhang,Xu Yang,Jun Dong,Wenxia Liu 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.2

In this study, a method for the low-carbon active distribution system (ADS) planning is proposed. It takes into account the impacts of both network capacity and demand correlation to the renewable energy accommodation, and incorporates demand response (DR) as an available resource in the ADS planning. The problem is formulated as a mixed integer nonlinear programming model, whereby the optimal allocation of renewable energy sources and the design of DR contract (i.e. payment incentives and default penalties) are determined simultaneously, in order to achieve the minimization of total cost and CO₂ emissions subjected to the system constraints. The uncertainties that involved are also considered by using the scenario synthesis method with the improved Taguchi’s orthogonal array testing for reducing information redundancy. A novel cuckoo search (CS) is applied for the planning optimization. The case study results confirm the effectiveness and superiority of the proposed method.

A topology optimization method for multiple load cases and constraints based on element independent nodal density

Jijun Yi,Jianhua Rong,Tao Zeng,X. Huang 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.6

In this paper, a topology optimization method based on the element independent nodal density (EIND) is developed for continuum solids with multiple load cases and multiple constraints. The optimization problem is formulated as minimizing the volume subject to displacement constraints. Nodal densities of the finite element mesh are used as the design variables. The nodal densities are interpolated into any point in the design domain by the Shepard interpolation scheme and the Heaviside function. Without using additional constraints (such as the filtering technique), mesh-independent, checkerboard-free, distinct optimal topology can be obtained. Adopting the rational approximation for material properties (RAMP), the topology optimization procedure is implemented using a solid isotropic material with penalization (SIMP) method and a dual programming optimization algorithm. The computational efficiency is greatly improved by multithread parallel computing with OpenMP to run parallel programs for the shared-memory model of parallel computation. Finally, several examples are presented to demonstrate the effectiveness of the developed techniques.

A topology optimization method of multiple load cases and constraints based on element independent nodal density

Yi, Jijun,Rong, Jianhua,Zeng, Tao,Huang, X. Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.6

In this paper, a topology optimization method based on the element independent nodal density (EIND) is developed for continuum solids with multiple load cases and multiple constraints. The optimization problem is formulated ad minimizing the volume subject to displacement constraints. Nodal densities of the finite element mesh are used a the design variable. The nodal densities are interpolated into any point in the design domain by the Shepard interpolation scheme and the Heaviside function. Without using additional constraints (such ad the filtering technique), mesh-independent, checkerboard-free, distinct optimal topology can be obtained. Adopting the rational approximation for material properties (RAMP), the topology optimization procedure is implemented using a solid isotropic material with penalization (SIMP) method and a dual programming optimization algorithm. The computational efficiency is greatly improved by multithread parallel computing with OpenMP to run parallel programs for the shared-memory model of parallel computation. Finally, several examples are presented to demonstrate the effectiveness of the developed techniques.

A kind of core cross-linked ‘‘semi-amphiphilic” polymer assemblies for controlled release of corrosion inhibitors and autonomous corrosion alarm

Ying Cao,Aoqi Zhu,Jianmin He,Jianhua Wu,Mingjin Xue,Yiting Xu,Birong Zeng,Guorong Chen,Lizong Dai 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.115 No.-

A novel kind of core cross-linked assemblies formed from a ‘‘semi-amphiphilic” block copolymer, poly(syringaldehyde methacrylate)-block-poly (dopamine methacrylate-co-methyl methacrylate-costyrene)(PSMA-b-P(DMA-co-MMA-co-St)), was designed and served as the carrier for anti-corrosiveand corrosion detective molecules. Different from the core cross-linked micelles formed by the amphiphilicpolymers in water, the core cross-linked assemblies in this research were formed from the ‘‘semiamphiphilic”block copolymer, which took advantage of the different compatibility between epoxy andthe blocks in the polymer, leading to the self-assembly behavior happening in the organic resin, whilethey shared the advantages of traditional core cross-linked micelles with the properties of being stable,stimuli-responsive and multifunctional. The pH-responsive properties of the assemblies and their complexationwith Fe3+ caused by the corrosion of the steel were confirmed by UV spectrophotometry andXPS analysis of the corrosive products. The controlled release of corrosion inhibitors was fully reflectedby the expansion of the capacitor ring and the increase of the coating resistance (Rc) with the extensionof the immersion time, which was got via fitting the electrochemical impedance spectroscopy (EIS) datawith the equivalent electric circuits. Ultimately, the anti-corrosive mechanism of smart coating with thefunctional core cross-linked assemblies were also illustrated.