A Simple and Rapid Phosphorescence Probe Based on Mn-Doped ZnS Quantum Dots for Chloramphenicol Detection

Zhenping Liu,Xianfeng Wang,Jingzhou Hou,Danqun Huo,Changjun Hou 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.11

An innovative phosphorescence probe based on Mn-doped ZnS quantum dots (Mn:ZnS QDs) was developed for selective detection of chloramphenicol (CAP) via inner-filter effect (IFE). Mn:ZnS QDs were synthesized by water method and modified with L-Cysteine for better stability, and the average diameter of the nanometer particle was 3.8 nm. With the excitation wavelength at 289 nm, the strong phosphorescence of Mn:ZnS QDs can be emitted at 583 nm. The excitation spectrum of Mn:ZnS QDs was substantially overlapped with the absorption spectrum of the target CAP. The excited light of Mn:ZnS QDs can be absorbed partially by CAP when they coexist, the phosphorescence intensity decreased with the increasing concentration of CAP, and it has a good linear relationship. Under optimal conditions, the linear relational concentration range achieved four orders of magnitude from 25 to 1.2 x 10 5 ng · mL -1 (R2 = 0.999), with a detection limit (LOD; S/N = 3) down to 0.81 ng · mL -1. The simple, rapid and low cost IFE phosphorescent probe exhibited satisfactory recoveries ranging from 88.9% to 98.5% for CAP analysis in spiked honey, which shows a potential for routine screening of CAP in ensuring the food safety.

新加坡華文敎學中的中華文化內容初探 -- 建構《中華文化敎學大綱》的若干思考

刘振平 ( Liu Zhenping ) 중국학연구회 2011 中國學硏究 Vol.- No.55

Learners involved in the teaching of Chinese in Singapore fall into two groups in terms of their linguistic and cultural backgrounds: students from Chinese-speaking families and students from English-speaking families. With respect to the former group of learners, Chinese teaching should introduce semantic culture rather than structural culture and pragmatic culture. On the other hand, Chinese is a second language for learners from the latter group. It is, therefore, necessary to list out the cultural content needed by these students on the basis of their background knowledge of Chinese culture and the relevant findings in China’s research on teaching Chinese as a second language. The incorporation of cultural content into the teaching of Chinese for both groups of leaner has the following objectives: 1) to increase identity recognition of Chinese Singaporeans, 2) to enhance the racial unity in Singapore, 3) to establish positive attitude to life and 4) to develop benevolence and good taste.

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.-

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.

Dynamic Parameters Updating of Earth-rock Dams Based on Modal Parameter Identification

Maohua Wang,Shichun Chi,Zhenping Liu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.10

The reasonable selection of dynamic parameters of earth-rock dams is very important for the seismic safety assessment of dams. Because of the size effects, the parameters acquired from the indoor test may additionally no longer exactly reflect the real dynamic characteristics of the dam. Therefore, it is essential to correct and update the dynamic parameters in accordance to the actual seismic dynamic characteristics of the dam. In this paper, by combining the Covariance-driven stochastic subspace identification (SSI-COV) method and the multiple population genetic algorithm (MPGA), an optimization and updating method for the dynamic parameters of earth-rock dams based on modal parameter identification is presented. The collected weak earthquake records of the dam allowed the modal parameters (the natural frequencies and mode shapes) identification based on SSI-COV method. The optimization updated is performed using the MPGA, which can obtain the optimal values of dynamic parameters of the dam and has good robustness within the optimization range of the numerical model. A typical numerical example is given to exhibit the feasibility and effectiveness of the presented method. Then the dynamic parameters of Liyutan Dam are updated by the proposed method according to the weak earthquake records, and the accuracy and applicability of the updated parameters were further verified by the strong earthquake records. The results show that the method proposed in this paper can provide a good idea for the calibration of dynamic parameters of earth-rock dams and has well practical engineering value.

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.

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.