Electronic Transport and Magnetic Properties in Y<SUB>0.125</SUB>Ca<SUB>0.875</SUB>MnO₃ Perovskites

Zhenping Chen,Yuefeng Li,Yuling Su,Dewei Liu,Chunmei Wang,Jincang Zhang 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Novel Rhodamine B and 2H-benzo[b][1,4]oxazin-3(4H)-one-derived Fluorescent Sensor for Low pH Value Detection

Mingjun Chen,Xueke Bai,Zhenping Qi,Shoubo Xiang,Hua Zuo,최경민,신동수 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.8

A new fluorescent probe L fusing the rhodamine B scaffold with 2H-benzo[b][1,4]oxazin-3(4H)-one moiety has been developed and applied as an acidic pH sensor. The ultraviolet (UV) and fluorescence spectra of the probe at different pH values were investigated in B?R buffer/MeOH (v: v = 3: 7). This probe showed increase of both the UV?Vis absorption and fluorescence emission from alkaline/neutral to acidic condition, reaching a strongest intensity at pH 2.13, but the intensities decreased when the pH decreased to 1.83. The color variation along the pH changes proved that the probe L can be used as a low-cost optical sensor for the naked eye detection of proton in the present buffer.

Nonlinear Control of Heterogeneous Vehicle Platoon with Time-varying Delays and Limited Communication Range

Haifeng Li,Zhenping Chen,Baochuan Fu,Manman Sun 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.6

Vehicle platooning can significantly increase throughput of transportation, while the impairment of communication may affect the control performance of vehicle platooning. Communication delays are inevitable in the process of driving, which will cause the instability of the platoon. Moreover, the transmission power level between vehicles is finite, resulting in a limited communication range. A nonlinear control algorithm is proposed where the car-following interactions between vehicles are considered. First, a third-order heterogeneous dynamic model is established for vehicles in the platoon. The control gains and parameters are heterogeneous. Then considering the constant time headway spacing policy and the gap supplement, conditions of the control gains for maintaining the internal stability of the platoon are obtained. Second, with time-varying communication delays taken into account, the allowed upper bound of communication delays is derived. Third, given the ability of each vehicle to receive information from multiple predecessors and followers, conditions of string stability are obtained, where the communication range is limited. Finally, numerical simulations are conducted to demonstrate the effectiveness of the proposed controller.

Atom Transfer Radical Polymerization of Hexadecyl Acrylate Using CuSCN as the Catalyst

Xu, Wenjian,Zhu, Xiulin,Cheng, Zhenping,Chen, Jianying,Lu, Jianmei The Polymer Society of Korea 2004 Macromolecular Research Vol.12 No.1

The atom transfer radical polymerization (ATRP) of hexadecyl acrylate (HDA) was carried out in Ν,Ν-dimethylformamide (DMF) in the presence of CuSCN/Ν,Ν,Ν′,Ν"Ν"-pentamethyldiethylenetriamine (PMDETA). The results indicate that the polymerization is well-controlled: a linear increase of molecular weights occurs with respect to conversion and the polydispersities are relatively low. In particular, the use of CuSCN as the catalyst resulted in faster polymerization rates for hexadecyl acrylate than did those using either CuBr or CuCl; the polydis-persity, however, was larger than those obtained in the cases when CuBr and CuCl were used. In addition, we report the thermodynamic data and activation parameters for the solution ATRP of hexadecyl acrylate.

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.

A fast sampling algorithm for energy-angle distributions of bremsstrahlung photon for radiotherapy applications

Wasaye Muhammad Abdul,Yu Tao,Xie Jinsen,Chen Zhenping,Ni Zining 한국물리학회 2023 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.82 No.10

A fast sampling algorithm for energy-angle distributions of bremsstrahlung photon for radiotherapy purposes is presented. Efcient and accurate sampling methods have been developed based on the most accurate and reliable diferential cross-sections for sampling the energy-angle distributions of bremsstrahlung photons by incident electron of energy 1 MeV–20 MeV. Scaled energy-loss numerical diferential cross-sections produced by Seltzer and Berger are used to sample the photon energy. A new sampling method based on a double diferential cross-section of Koch and Motz has been developed which uses a simplifed expression to sample the bremsstrahlung photon angular distribution. The average efciency of sampling photon energy distribution algorithm is about 85% for electrons with kinetic energies 5 MeV–20 MeV and below to 75% for electrons of kinetic energies 1 MeV–5 MeV. Computation time comparisons have been evaluated with the previous algorithm to sample one photon energy. The inverse transform sampling procedure is implemented to sample the photon angular distribution; hence, every sampled value of the angular distribution is accepted. Therefore, the proposed algorithm is very fast and efcient for radiotherapy purposes. The sampling methods’ accuracy is checked by comparing the Monte Carlo sampled distributions with the theoretical expressions.

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.

Radiation shielding optimization design research based on bare-bones particle swarm optimization algorithm

Jichong Lei,Chao Yang,Huajian Zhang,Chengwei Liu,Dapeng Yan,Guanfei Xiao,Zhen He,Zhenping Chen,Tao Yu Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.6

In order to further meet the requirements of weight, volume, and dose minimization for new nuclear energy devices, the bare-bones multi-objective particle swarm optimization algorithm is used to automatically and iteratively optimize the design parameters of radiation shielding system material, thickness, and structure. The radiation shielding optimization program based on the bare-bones particle swarm optimization algorithm is developed and coupled into the reactor radiation shielding multi-objective intelligent optimization platform, and the code is verified by using the Savannah benchmark model. The material type and thickness of Savannah model were optimized by using the BBMOPSO algorithm to call the dose calculation code, the integrated optimized data showed that the weight decreased by 78.77%, the volume decreased by 23.10% and the dose rate decreased by 72.41% compared with the initial solution. The results show that the method can get the best radiation shielding solution that meets a lot of different goals. This shows that the method is both effective and feasible, and it makes up for the lack of manual optimization.