Study on the Pressure-Volume-Temperature Properties of Polypropylene at Various Cooling and Shear Rates

Pengcheng Xie,Huaguang Yang,Tianze Cai,Zheng Li,Yuelin Li,Weimin Yang 한국고분자학회 2018 폴리머 Vol.42 No.2

To understand the pressure-volume-temperature (PVT) properties of polymer in injection process, a dilatometer with high cooling rate (up to 25 oC/s) and shear rate (up to 320 s-1) was developed. The working pressure and temperature of the dilatometer range from 0 to 100 MPa, and from 30 to 300 oC, respectively. With this instrument, a crystalline polymer polypropylene (PP) was employed to study the effects of cooling rate, shear rate, pressure and their coupling effect on its PVT properties. It was demonstrated that the cooling rate showed a significant effect on the PVT properties. With the increase of cooling rate, the transition temperature of PP from melt state to crystallization decreases gradually and the temperature range of crystallization was also extended. Shear increased the transition temperature of PP from melt state to crystallization. Meanwhile, the initial temperature of shear and crystalline segment was shifted to a higher temperature region with increasing shear duration or shear rate. Above the transition temperature, the effect of shear on the PVT properties weakened gradually with increasing the initial temperature. The coupling analysis of cooling and shear processes showed that increase in cooling rate was enhanced the effect of shear on the transition temperature of PP from melt state to crystallization.

THE ECONOMIC IMPACTS OF CARBON TRADING MECHANISM ON THE DEVELOPMENT OF PV PROJECTS IN GUANGDONG PROVINCE

Pengcheng XIE,Wenjun WANG,Daiqing ZHAO,Cuiping Liao 한국신재생에너지학회 2017 AFORE Vol.2017 No.11

Effect of Compositions on the Microstructure and Properties of Plasma Clad NiAl Coating

Pengcheng Xia,Guanpeng Han,Kun Xie 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.3

NiAl intermetallic coating was in-situ synthesized by the plasma cladding process. The effect of atomic ratio of Ni to Al atoms 1 (coating 1), 2 (coating 2) and 3 (coating 3) on the microstructure and mechanical properties of plasma clad was studied by combining microstructural analysis and wear-resistant test. The obtained results indicated that the microstructure of the synthesized NiAl coating was compact and uniform in addition to few porosities and the NiAl coating well metallurgically bonded with the substrate. Coating 1 is mainly composed of NiAl and the solid solution γ-(Fe,Ni) phases. Coating 2 contains of NiAl, Ni3Al and γ-(Fe,Ni). Coating 3 is mainly composed of Ni3Al, γ-(Fe,Ni) and NiAl. Coating 3 has excellent wear-resistance property owing to high hardness and low friction coefficient. Ni3Al phase has great influence on wear-resistance property of coating 3. The main wear mechanism of coating 1 is multi-plastic deformation wear and adhesion wear. Grain abrasion is the main wear mechanism of coating 3. The main wear mechanism of coating 2 is grain abrasion and partly adhesive wear.

Code development on steady-state thermal-hydraulic for small modular natural circulation lead-based fast reactor

Zhao, Pengcheng,Liu, Zijing,Yu, Tao,Xie, Jinsen,Chen, Zhenping,Shen, Chong Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.12

Small Modular Reactors (SMRs) are attracting wide attention due to their outstanding performance, extensive studies have been carried out for lead-based fast reactors (LFRs) that cooled with Lead or Lead-bismuth (LBE), and small modular natural circulation LFR is one of the promising candidates for SMRs and LFRs development. One of the challenges for the design small modular natural circulation LFR is to master the natural circulation thermal-hydraulic performance in the reactor primary circuit, while the natural circulation characteristics is a coupled thermal-hydraulic problem of the core thermal power, the primary loop layout and the operating state of secondary cooling system etc. Thus, accurate predicting the natural circulation LFRs thermal-hydraulic features are highly required for conducting reactor operating condition evaluate and Thermal hydraulic design optimization. In this study, a thermal-hydraulic analysis code is developed for small modular natural circulation LFRs, which is based on several mathematical models for natural circulation originally. A small modular natural circulation LBE cooled fast reactor named URANUS developed by Korea is chosen to assess the code's capability. Comparisons are performed to demonstrate the accuracy of the code by the calculation results of MARS, and the key thermal-hydraulic parameters agree fairly well with the MARS ones. As a typical application case, steady-state analyses were conducted to have an assessment of thermal-hydraulic behavior under nominal condition, and several parameters affecting natural circulation were evaluated. What's more, two characteristics parameters that used to analyze natural circulation LFRs natural circulation capacity were established. The analyses show that the core thermal power, thermal center difference and flow resistance is the main factors affecting the reactor natural circulation. Improving the core thermal power, increasing the thermal center difference and decreasing the flow resistance can significantly increase the reactor mass flow rate. Characteristics parameters can be used to quickly evaluate the natural circulation capacity of natural circulation LFR under normal operating conditions.

CLIMATE VULNERABILITY ASSESSMENT AND COMPARISON OF SOLAR AND WIND POWER IN SOUTHERN CHINA

Wenjun WANG,Pengcheng XIE,Wenxiu WANG,Xujie ZHAO,Daiqing zhao 한국신재생에너지학회 2017 AFORE Vol.2017 No.11

Adaptive Switch Image-based Visual Servoing for Industrial Robots

Ahmad Ghasemi,Pengcheng Li,Wen-Fang Xie 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.5

In this paper, an adaptive switch image-based visual servoing (IBVS) controller for industrial robots is presented. The proposed control algorithm decouples the rotational and translational camera motions and decomposes the IBVS control into three separate stages with different gains. This method can increase the system response speed and improve the tracking performance of IBVS while the proposed adaptive law deals with the uncertainties of the monocular camera in eye-in-hand configuration. The stability of the designed controller is proved using Lyapunov method. Experimental results on a 6 degree of freedom (DOF) robot show the significant enhancement of the control performance over other IBVS methods, in terms of the response time and tracking performance. Also the designed visual servoing controller demonstrates its capability to overcome some of the inherent drawbacks of IBVS, such its inability to perform a 180◦ camera rotation around its center.

Research on Ground Penetrating Radar Image Denoising Using Nonsubsampled Contourlet Transform and Adaptive Threshold Algorithm

Wu Peng,Xu Hongling,Xie Pengcheng 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.5

Aiming at the problem of ground penetrating radar image denoising, a new adaptive image denoising algorithm based on nonsubsampled Contourlet transform is proposed. The algorithm firstly performs nonsubsampled Contourlet transform to the noise image, to obtain the coefficients of each directional sub band and each scale, then, according to the energy of the coefficient, the denoising threshold value is adjusted adaptively. Simulation results show that, compared with the wavelet threshold denoising algorithm, the proposed algorithm can effectively remove the Gauss white noise in the image, improve the peak signal to noise ratio (PNSR), while preserving the edge details of the image, it can improve the PSNR value and reduce the Gibbs phenomenon.

Enhancement of the Molding Quality of Light Guide Plates by means of Multi-Coating Surface Treatments of the Injection Molding Screw

Ranran Jian,Weimin Yang,Pengcheng Xie 한국고분자학회 2017 폴리머 Vol.41 No.1

The effects of different surface treatments of an injection molding screw have been investigated using light guide plates as a representative precision component. The quality of the fabricated light guide plates was compared for different screw coatings, using the stripping performance, surface microstructure and adhesion strength as criteria. In addition, the results obtained using different combinations of screw coatings were analyzed in order to identify the optimum screw surface treatment method for the large scale production of polycarbonate light guide plates. It was found that light guide plate parts fabricated using a screw with a TiAlN/Cr multi-coating had the best performance, with a defect percentage of only 0.11%, much lower than the value of 19.21% obtained using a screw with a conventional hard chrome coating.

Numerical Simulation on the Enhanced Mixing of Polymer Melt by Single Screw with Torsion Elements in the Homogenizing Section

Ranran Jian,Weimin Yang,Lisheng Cheng,Pengcheng Xie 한국고분자학회 2018 폴리머 Vol.42 No.6

As one of key factors that determine the quality of products, the homogenization of polymer melt is closely dependent on the mixing of polymers. The mixing of polymer melt in the homogenizing section by a single screw with torsion elements was analyzed with the computational fluid dynamics (CFD) simulation. The simulation results reveal that screws with such torsion elements arranged in a decentralized form have smaller segregation scale, distribution index and higher mixing efficiency, compared with the conventional screw. The decentralized arrangement is more effective for mixing than the centralized distribution. The rotational flow induced by the torsion elements can significantly enhance the mass transfer process and improve mixing and plasticizing. Compared with those in conventional screw, the distributions of temperature and viscosity are more uniform at the outlet of torsion screws, which also made the torsion element generally more effective and efficient for mixing and plasticizing.

Neutronic Study of Utilization of Discrete Thorium-Uranium Fuel Pins in CANDU-6 Reactor

Nianbiao Deng,Tao Yu,Jinsen Xie,Zhenping Chen,Qin Xie,Pengcheng Zhao,Zijing Liu,Wenjie Zeng 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.2

Targeting at simulating the application of thorium-uranium (TU) fuel in the CANDU-6 reactor, this paperanalyzes the process using the code DRAGON/DONJON where the discrete TU fuel pins are applied in theCANDU-6 reactor under the time-average equilibrium refueling. The results show that the coolant voidreactivity of the assembly analyzed in this paper is lower than that of 37-element bundle cell withnatural uranium and 37-element bundle cell with mixed TU fuel pins; that the max time-averagechannel/bundle power of the core meets the limits - less than 6700kW/860 kW; that the fuel conversionratio is higher than that of the CANDU-6 reactor with natural uranium; and that the exit burnupincreases to 13400 MWd/tU. Thus, the simulation in this paper with the fuel in the 37-element bundlecell using discrete TU fuel pins can be considered to be applied in CANDU-6 reactor with adequatemodifications of the core structure and operating modes.