Multi-channel analyzer based on a novel pulse fi tting analysis method

Qingshan Wang,Xiongjie Zhang,Xiangting Meng,Bao Wang,Dongyang Wang,Pengfei Zhou,Renbo Wang,Bin Tang 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.6

A novel pulse fitting analysis (PFA) method is presented for the acquisition of nuclear spectra. Thecharging process of the feedback capacitor in the resistive feedback charge-sensitive preamplifier isequivalent to the impulsive pulse, and its impulse response function (IRF) can be obtained by non-linearfitting of the falling edge of the nuclear pulse. The integral of the IRF excluding the baseline representsthe energy deposition of the particles in the detector. In addition, since the non-linear fitting process inPFA method is difficult to achieve in the conventional architecture of spectroscopy system, a new multichannel analyzer (MCA) based on Zynq SoC is proposed, which transmits all the data of nuclear pulsesfrom the programmable logic (PL) to the processing system (PS) by high-speed AXI-Stream in order toimplement PFA method with precision. The linearity of new MCA has been tested. The spectrum of 137Cswas obtained using LaBr3(Ce) scintillator detector, and was compared with commercial MCA by ORTEC. The results of tests indicate that the MCA based on PFA method has the same performance as thecommercial MCA based on pulse height analysis (PHA) method and excellent linearity for g-rays withdifferent energies, which infers that PFA method is an effective and promising method for the acquisitionof spectra. Furthermore, it provides a new solution for nuclear pulse processing algorithms involvingregression and iterative processes

The detection efficiency study of NaI(Tl) scintillation detector with the different numbers of SiPMs

Wang Bao,Zhang Xiongjie,Wang Qingshan,Wang Dongyang,Li Dong,Xiahou Mingdong,Zhou Pengfei,Ye Hao,Hu Bin,Zhang Lijiao 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.7

SiPMs are generally coupled into whole columns in gamma energy spectrum measurement, but the relationship between the distribution of whole SiPM columns and the energy resolution of the measured energy spectra is rarely reported. In this work, ∅ 3 3 inch NaI scintillator is placed on an 8 8 SiPM array, and the energy resolution of the 137Cs peak at 662 keV corresponding to the g-ray is selected as a reference. Each SiPM is switched to explore the influence of the number of SiPM arrays, distribution position, and reflective layer on the energy resolution of SiPMs. Results show that without coupling, the energy resolution is greatly improved when the number of SiPMs ranges from 4 to 32. However, after 32 slices (the area covered by SiPMs relative to the scintillator reaches 25.9%), the improvement in energy resolution and total pulse count is not obvious. In addition, the position of SiPMs relative to the scintillator does not exert much impact on the energy resolution. Results also indicate that by adding a reflective film (ESR), the energy resolution of the tested group increases by 10.38% on average. This work can provide a reference for the design and application of miniaturized SiPM gamma spectrometers

Interfacial behaviors in Cu/molten Sn–58Bi/Cu solder joints under coupling with thermal and current stressing

Fengjiang Wang,Hong Chen,Dongyang Li,Zhijie Zhang,Xiaojing Wang 대한금속·재료학회 2019 ELECTRONIC MATERIALS LETTERS Vol.15 No.1

The interfacial behaviors of Cu/molten Sn–58Bi/Cu solder joints under the coupling eff ect of a temperature gradient and thecurrent stressing have been investigated. The most obvious change of the interfacial behaviors under the individual electromigration(EM) and thermomigration (TM) in molten solder was the asymmetrical growth of interfacial Cu–Sn intermetalliccompounds (IMCs), which grew rapidly as the stressing time prolonged. The growth rates of the interfacial IMCs inducedby TM under a temperature gradient of 40 °C/cm were slightly faster than EM under the current density of 0.5 × 10 4 A/cm 2 . However, the microstructure evolution and interfacial behaviors changed obviously when the thermal was distributedunevenly across the entire solder stripe under current stressing. It was found that there was a Bi-rich layer adhered to theanode side and a distributed Cu 6 Sn 5 phase existed in the solder matrix when the anode and the cold end were at the sameend. Additionally, a large number of Bi-blocks and Cu–Sn IMCs were dramatically observed in the solder matrix when theanode and the hot end were on the same side. The main reason for this result may be attributed to the signifi cant change ofthe diff usion of Bi atoms under the thermo-electric coupling conditions. In the initial melting stage of solder, the Bi atomsin molten Sn–58Bi solder rapidly diff used to the anode and then began to be reversely dissolved into the solder matrix. Theexperimental results proved the additional temperature gradient played a positive or negative role on the reverse dissolutionof Bi atoms in the heat preservation process.

Elimination of the State-of-Charge Errors for Distributed Battery Energy Storage Devices in Islanded Droop-controlled Microgrids

Wang, Weixin,Wu, Fengjiang,Zhao, Ke,Sun, Li,Duan, Jiandong,Sun, Dongyang The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.4

Battery energy storage devices (ESDs) have become more and more commonplace to maintain the stability of islanded power systems. Considering the limitation in inverter capacity and the requirement of flexibility in the ESD, the droop control was implemented in paralleled ESDs for higher capacity and autonomous operation. Under the conventional droop control, state-of-charge (SoC) errors between paralleled ESDs is inevitable in the discharging operation. Thus, some ESDs cease operation earlier than expected. This paper proposes an adaptive accelerating parameter to improve the performance of the SoC error eliminating droop controller under the constraints of a microgrid. The SoC of a battery ESD is employed in the active power droop coefficient, which could eliminate the SoC error during the discharging process. In addition, to expedite the process of SoC error elimination, an adaptive accelerating parameter is dedicated to weaken the adverse effect of the constraints due to the requirement of the system running. Moreover, the stability and feasibility of the proposed control strategy are confirmed by small-signal analysis. The effectiveness of the control scheme is validated by simulation and experiment results.

A rule-based classifier ensemble for fault diagnosis of rotating machinery

Dongyang Dou,Jian Jiang,Yuling Wang,Yong Zhang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.6

To predict potential problems and avoid an unexpected breakdown of rotating machinery, a rule-based classifier ensemble approach is presented. Feature reduction was first implemented on a fault decision table using discernibility matrices and the genetic algorithm. The generated rules of the reducts were used to build the candidate base classifiers. Then, several base classifiers were selected according to their diversity and scale. The weights of the selected base classifiers were also calculated based on the support rate measurements. A classifier ensemble was constructed through an integration of the base classifiers using an improved weighted voting technique. Finally, the proposed classifier ensemble was verified based on the vibration data of bearing types SKF6203 and NU205. The accuracy for the SKF6203 bearing type reached 88.75 %, which is at least 5 % higher than that of the three base classifiers for this type of bearing. In addition, the recognition rate for the latter bearing type was 90 %. The reasoning process was much easier to comprehend owing to the semantic descriptions of the rules. The results show that this is a promising and transparent approach for diagnosing typical faults of rotating machinery.

Elimination of the State-of-Charge Errors for Distributed Battery Energy Storage Devices in Islanded Droop-controlled Microgrids

Weixin Wang,Fengjiang Wu,Ke Zhao,Li Sun,Jiandong Duan,Dongyang Sun 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.4

Battery energy storage devices (ESDs) have become more and more commonplace to maintain the stability of islanded power systems. Considering the limitation in inverter capacity and the requirement of flexibility in the ESD, the droop control was implemented in paralleled ESDs for higher capacity and autonomous operation. Under the conventional droop control, state-of-charge (SoC) errors between paralleled ESDs is inevitable in the discharging operation. Thus, some ESDs cease operation earlier than expected. This paper proposes an adaptive accelerating parameter to improve the performance of the SoC error eliminating droop controller under the constraints of a microgrid. The SoC of a battery ESD is employed in the active power droop coefficient, which could eliminate the SoC error during the discharging process. In addition, to expedite the process of SoC error elimination, an adaptive accelerating parameter is dedicated to weaken the adverse effect of the constraints due to the requirement of the system running. Moreover, the stability and feasibility of the proposed control strategy are confirmed by small-signal analysis. The effectiveness of the control scheme is validated by simulation and experiment results.

Case Study of Modified H–B Strength Criterion in Discrimination of Surrounding Rock Loose Circle

Rui Wang,Xianghui Deng,Yaoyao Meng,Dongyang Yuan,Daohong Xia 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.3

Intermediate principal stress is a significant factor when calculate to determine the surrounding rock loose circles. Based on it, this paper is trying to modify the Hoek–Brown strength criterion, and put forwards a theoretical formula of the loose circle radius. The theoretical formula is applied to Shimen Tunnel, and a comparative analysis between theoretical calculations and field test results is conducted. Here are the results as follows: 1) With an increase of intermediate principal stress, the strength of the rock mass increases and the surrounding rock becomes more difficult to break. Consequently, loose circle thickness is gradually reduced and forms a significant negative linear relationship with the Lode parameter. 2) The results indicate that with a decrease of surrounding rock level in a three-lane hard rock tunnel, the radius of the loose circle increases continuously. 3) The results of the field acoustic wave test show that the theoretical calculation values are consistent with the field measurement results. According to above analysis, the deduced formula is feasible.

Disease Prevention Knowledge, Anxiety, and Professional Identity during COVID-19 Pandemic in Nursing Students in Zhengzhou, China

Sun, Yuyan,Wang, Dongyang,Han, Ziting,Gao, Jie,Zhu, Shanshan,Zhang, Huimin 한국간호과학회 2020 Journal of Korean Academy of Nursing Vol.50 No.4

Purpose: This study aimed to evaluate nursing students’ understanding of the prevention of COVID-19, as well as their anxiety towards the disease and their perception of their professional identity in the wake of the pandemic, in Zhengzhou, China. Methods: A cross-sectional study was designed to investigate 474 nursing students by cluster sampling using a stratified questionnaire from February 15 to March 31, 2020. Multiple linear regression was used to identify the factors affecting professional identity. Binary and multiple logistic regression were used to identify the factors affecting anxiety. Results: Responders with a high level of understanding of COVID-19 and frequent use of behavioral strategies for its prevention comprised 93.2% and 30.0% of the cohort, respectively. Professional identity was significantly associated with gender and anxiety (p < .050). The prevalence of anxiety among nursing students was 12.4%. Male (odds ratio [OR] = 2.39; 95% confidence interval [CI] = 1.26~4.52), sophomores (OR = 5.30; 95% CI = 1.61~7.45), and infrequent use of prevention measures (OR = 3.49; 95% CI = 1.16~5.19) had a significant effect on anxiety. Conclusion: Anxiety during the COVID-19 epidemic gives an adverse effect on the professional identity of nursing in students. Nursing education institutions need to provide psychological counseling services for nursing students, in addition to improving their teaching of COVID-19 prevention strategies.

An Adaptive Trust Sampling Method for P2P Traffic Inspection

Hongwei Chen,Dongyang Yu,Chunzhi Wang,Shuping Wang 보안공학연구지원센터(IJGDC) 2013 International Journal of Grid and Distributed Comp Vol.6 No.6

Application and Research of Monte Carlo Sampling Algorithm in Music Generation

Jun MIN,Lei WANG,Junwei PANG,Huihui HAN,Dongyang Li,Maoqing ZHANG,Yantai HUANG 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.10

Composing music is an inspired yet challenging task, in that the process involves many considerations such as assigning pitches, determining rhythm, and arranging accompaniment. Algorithmic composition aims to develop algorithms for music composition. Recently, algorithmic composition using artificial intelligence technologies received considerable attention. In particular, computational intelligence is widely used and achieves promising results in the creation of music. This paper attempts to provide a survey on the music generation based on the Monte Carlo (MC) algorithm. First, transform the MIDI music format files to digital data. Among these data, use the logistic fitting method to fit the time series, obtain the time distribution regular pattern. Except for time series, the converted data also includes duration, pitch, and velocity. Second, using MC simulation to deal with them summed up their distribution law respectively. The two main control parameters are the value of discrete sampling and standard deviation. Processing the above parameters and converting the data to MIDI file, then compared with the output generated by LSTM neural network, evaluate the music comprehensively.