Study on Energy Matching methods for Ultra High-Speed Generator System Based on Qualitative Modelling Analysis

Zhang Xiangjun,Li gengyao,Liu Hankui,Wang Yijie,Xu Dianguo 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In high speed aircraft, Ultra high-speed generator’s safe operation and smooth power supply to load would be threatened by mismatching between open-loop generator and the fickle load condition. In this paper, a power converter with paralleled energy-matching link was developed, which can broaden safe operation zone and ensure generator’s safe operation as well as load’s smooth power supply under relatively light load conditions. This power converter can also ensure power supply voltage following under relatively heavy load conditions. The validity was verified by experiment results.

플립트 러닝을 활용한 성인 중국어회화 학습이 학업성취도와 수업만족도에 미치는 영향

장상군(Xiangjun, Zhang),정선영(Sunyoung, Jung) 국민대학교 교육연구소 2021 교육논총 Vol.38 No.1

글로벌 시대에 맞춰 우수한 중국어 능력을 갖춘 인재를 필요로 하는 곳이 점점 많아지고 있다. 언어에 효과적인 학습방법 중 하나가 반복연습인데 이를 효과적으로 할 수 있는 대안으로서 플립트 러닝(Flipped Learning)이 많이 소개되고 있다. 본 연구는 플립트 러닝을 활용한 중국어회화 수업이 전통 강의식 수업방식을 적용한 집단과 중국어 학업성취도와 수업만족도에서 차이가 있는지 알아보고자 하였다. 이에 따른 연구문제는 다음과 같다. 첫째, 플립트 러닝을 활용한 성인 중국어 회화 학습프로그램을 처치한 실험집단의 학업 성취도는 그렇지 않은 통제집단의 학업 성취도와 차이가 있는가? 둘째, 플립트 러닝을 활용한 성인 중국어회화 학습프로그램을 처치한 실험집단의 수업 만족도는 그렇지 않은 통제집단의 수업 만족도와 차이가 있는가? 이다. 본 연구의 대상은 서울특별시 소재한 P동과 경기도에 소재한 G동 주민센터의 중국어 교실에서 가르치고 있는 성인으로, 플립트 러닝을 적용하는 실험집단과 전통적 강의식 수업방식을 적용하는 통제집단으로 구분하여 연구를 진행하였다. 실험집단 25명과 통제집단 23명으로 총 48명을 모집하여 실험을 실시하였다. 연구결과 플립트 러닝을 활용한 성인 중국어회화 학습프로그램을 처치한 실험집단과 그렇지 않은 통제집단 간에 학습자의 학업 성취도와 수업 만족도에 차이가 있었다. 본 연구의 결과는 성인 학습자의 효율적인 중국어회화 교육에 플립트 러닝의 활용이 효과적으로 활용될 수 있음을 시사한다. Since China is a country closely related to Korea, geographically and historically, the demand for Chinese language skills has been growing high in these days. The most effective way to learn a foreign language is to practice over and over again. Due to fact technology development, the flipped learning is introduced as a perfect method to resolve and overcome the difficulties in learning a foreign language. The purpose of this research is to find out differences in academic achievement and class satisfaction between two groups, the one taught by the flipped learning and the other taught by the traditional lecture. After examining the results of this research, I would like to suggest any implications to improve Chinese conversation class. Therefore, research problems are as follows: First, are there any differences in two student group s academic achievements in a Chinese conversation learning program: the one with flipped learning and the other with traditional lecture method? Second, are there any differences in two student group s satisfaction on a Chinese conversation learning program; the one with flipped learning and the other with the traditional lecture method? The study was treated to the students in Chinese language classes at P_dong in Kyeonggi-do and at G_dong in Seoul. 48 students were divided into either to an experimental group or treatment group. 25 students were assigned to the experimental group and 23 were to the control group. The experiment in this study had been conducted twice a week over 5 weeks for 50 minutes a class. Independent-sample t-test was used to examine the statistical differences in class satisfaction and academic achievement between two groups. The study concludes that the flipped learning program produced statistically higher scores in academic achievement and class satisfaction than those of control group taught by traditional lecture. Therefore, flipped learning can be effectively used to develop a Chinese language learning program.

Isolation and identification of a bacterial cellulose synthesizing strain from kombucha in different conditions: Gluconacetobacter xylinus ZHCJ618

Zhang, Wen,Wang, Xuechuan,Qi, Xiangjun,Ren, Longfang,Qiang, Taotao 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.3

A bacterial cellulose (BC) synthesizing strain (Gluconacetobacter xylinus ZHCJ618) was isolated from kombucha and selected as the species for commercial applications owing to its high phenotypic stability and sustainable production capacity of $7.56{\pm}0.57g/L$ under static culturing conditions and $8.31{\pm}0.79g/L$ under shaking conditions. The morphological, physiological and biochemical characteristics of the strain were similar to those of Gluconacetobacter genus. The 16S rDNA sequence homologies with G. xylinus NCIB 11664 reached 99%, showing that the isolated strain can be identified as G. xylinus. The material properties of BC were studied by fourier transform infrared spectroscopy, scanning electronic microscopy, X-ray diffraction, thermogravimetric analysis, and tensile test. The results showed that BC synthesized under static conditions exhibited stronger tear strength, higher crystallinity, superior waterhold and rehydration rate than BC synthesized under shaking conditions.

Isolation and identification of a bacterial cellulose synthesizing strain from kombucha in different conditions: Gluconacetobacter xylinus ZHCJ618

Wen Zhang,Xuechuan Wang,Xiangjun Qi,Longfang Ren,Taotao Qiang 한국식품과학회 2018 Food Science and Biotechnology Vol.27 No.3

A bacterial cellulose (BC) synthesizing strain (Gluconacetobacter xylinus ZHCJ618) was isolated from kombucha and selected as the species for commercial applications owing to its high phenotypic stability and sustainable production capacity of 7.56 ± 0.57 g/L under static culturing conditions and 8.31 ± 0.79 g/L under shaking conditions. The morphological, physiological and biochemical characteristics of the strain were similar to those of Gluconacetobacter genus. The 16S rDNA sequence homologies with G. xylinus NCIB 11664 reached 99%, showing that the isolated strain can be identified as G. xylinus. The material properties of BC were studied by fourier transform infrared spectroscopy, scanning electronic microscopy, X-ray diffraction, thermogravimetric analysis, and tensile test. The results showed that BC synthesized under static conditions exhibited stronger tear strength, higher crystallinity, superior waterhold and rehydration rate than BC synthesized under shaking conditions.

Predicting the Weed Control Efficacy of Photosynthesis Inhibitors by PPM Method

HONGJUN ZHANG,HAILAN CUI,JIMING YE,XUE LIU,XIANGJUN LI,CORNE KEMPENAAR,SHOUHUI WEI,HANWEN NI 韓國雜草學會 2009 Weed&Turfgrass Science Vol.29 No.3

The experiment was conducted in a greenhouse in Beijing, China, to determine whether weed control efficacy could be predicted based on Plant Photosynthesis Meter (PPM) values measured shortly after the application of photosynthesis inhibitors. The decrease of PPM values of the weed leaves treated with the mixture of atrazine and bentazone could be measured 1 day after treatment (DAT). The decreased extents depended on weed susceptibility and application dosage. There was significant correlation between the PPM values of the treated leaves 1 to 3 DAT and the biomass reduction 14 DAT. The experimental findings indicated that PPM values measured in early days after treatment could give reasonable prediction on weed control. The herbicide usually provided 90% control by weed biomass when PPM value was about 20 and relatively poor control when PPM value over 20.

Magnetorheology of suspensions based on graphene oxide coated or added carbonyl iron microspheres and sunflower oil

Chen, Kaikai,Zhang, Wen Ling,Shan, Lei,Zhang, Xiangjun,Meng, Yonggang,Choi, Hyoung Jin,Tian, Yu American Institute of Physics 2014 JOURNAL OF APPLIED PHYSICS - Vol.116 No.15

Digital Control Methods of Two-Stage Electronic Ballast for Metal Halide Lamps with a ZVS-QSW Converter

Wang, Yijie,Zhang, Xiangjun,Wang, Wei,Xu, Dianguo The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.5

This paper presents a new kind of digital control metal halide lamp electronic ballast. A zero-voltage-switch quasi-square-wave (ZVS-QSW) dual Buck converter is adopted here. In this paper, a digital control method is proposed to achieve ZVS for the converter. This ZVS can be realized during the whole working condition. Single-cycle-peak-current control is proposed to solve the problem of excessive inductor current during a low-frequency reversal transient. Power loop control is also realized and its consistency for different lamps is good. An AVR special microcontroller for a HID ballast is used to raise the control performance, and the low-frequency square-wave control method is adopted to avoid acoustic resonance. A 70W prototype was built in the laboratory. Experimental results show that the electronic ballast works reliably. Furthermore, the efficiency of the ballast can be higher than 92%.

Digital Control Methods of Two-Stage Electronic Ballast for Metal Halide Lamps with a ZVS-QSW Converter

Yijie Wang,Xiangjun Zhang,Wei Wang,Dianguo Xu 전력전자학회 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.5

This paper presents a new kind of digital control metal halide lamp electronic ballast. A zero-voltage-switch quasi-square-wave (ZVS-QSW) dual Buck converter is adopted here. In this paper, a digital control method is proposed to achieve ZVS for the converter. This ZVS can be realized during the whole working condition. Single-cycle-peak-current control is proposed to solve the problem of excessive inductor current during a low-frequency reversal transient. Power loop control is also realized and its consistency for different lamps is good. An AVR special microcontroller for a HID ballast is used to raise the control performance, and the low-frequency square-wave control method is adopted to avoid acoustic resonance. A 70W prototype was built in the laboratory. Experimental results show that the electronic ballast works reliably. Furthermore, the efficiency of the ballast can be higher than 92%.

초등학교 입학 이후 아동의 개인 요인과 학교 환경 요인이 학교 적응에 미치는 종단연구

최윤서(Choi Yoonseo),장상군(Zhang Xiangjun) 학습자중심교과교육학회 2022 학습자중심교과교육연구 Vol.22 No.6

목적 본 연구에서는 초등학교 입학 이후 개인 차원적 요인과 학교 환경적 요인인 성별, 자아존중감, 학업수행능력, 모의 양육행동과 교사-아동관계가 아동의 학교 적응에 어떤 영향을 미치는지를 종단연구를 통해 분석하고자 하였다. 방법 본 연구는 육아정책연구소에서 초등학교 1학년부터 초등학교 4학년을 대상으로 조사한 8-11차(2016년-2018년)의 종단자료를 사용하였다. 종단자료에서 나타난 결측치를 해결하기 위해 완전제거법(listwise deletion method)을 사용하여 최종 252명(남학생 = 127명, 여학생=125명)의 자료를 사용하였다. 본 연구는 초등학교 입학 후 초등학생들의 개인 및 학교 환경 요인이 학교 적응에 미치는 변화를 다층성장분석을 통해 살펴보았다. 결과 첫째, 초등학교 1학년부터 4학년까지의 아동의 학교 적응은 시간의 변화에 따라 미비하지만 긍정적으로 증가하는 것으로 나타났다. 둘째, 초등학생의 성별을 통제한 상태에서 초등학교 1학년~4학년 시기의 아동의 학교 적응 변화 궤적에 학업수행능력만이 통계적으로 유의미한 긍정적 영향을 미치는 것으로 나타났다. 셋째, 초등학생의 성별을 통제한 상태에서 초등학교 1학년~4학년 시기의 아동의 학교 적응 변화에 교사-아동관계는 통계적으로 유의미하고 긍정적 영향을 미치는 것으로 나타났다. 넷째, 초등학교 1학년~4학년 시기의 아동의 학교 적응 변화에 개인 변인 중 성별 그리고 학교 환경 요인의 교사-아동관계만이 통계적으로 유의미한 긍정적 영향을 미치는 것으로 나타났다. 결론 이러한 연구 분석 결과에 따라서 유치원⋅초등학교 전환기 아동들의 성공적인 학교적응을 위한 시사점을 논의하였다. Objectives The purpose of this study was to analyze longitudinally the effect of individual factors (gender, self-esteem, academic performance, and maternal parenting behavior) and school environmental factors (teacher-child relations) on the school adjustment of children after entering elementary school. Methods This study used the longitudinal data from 8th to 11th cycles (2016-2018) surveyed from 1st grade to 4th grade of elementary school by the Childcare Policy Research Institute. The listwise deletion method was used to solve the missing values in the longitudinal data, and the final 252 students (male=127, female=125) data were used. Through multi-level growth analysis, this study analyzed the changes of elementary school students individual and school environmental factors on school adjustment after elementary school enrollment. Results First, it was discovered that school adjustment of children in the first through fourth grades of elementary school was insufficient but increased over time. Second, while controlling for the gender of elementary school students, only academic performance had a statistically significant positive effect on the trajectory of changes in school adjustment of children in the first to fourth grades of elementary school. Third, while controlling for the gender of elementary school students, it was discovered that the teacher-child relationship had a statistically significant positive effect on the change in school adjustment of children in the first to fourth grades of elementary school. Fourth, among the individual variables, only gender and teacher-child relationship as school environmental factors had a statistically significant positive effect on the change in school adjustment of children in the first to fourth grades of elementary school. Conclusions Through this results, the implications for successful school adjustment of children were discussed.

Novel Interleaved Single-Stage AC/DC Converter with a High Power Factor and High Efficiency

Wang, Yijie,Wang, Wei,Zhang, Xiangjun,Xu, Dianguo The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.3

A novel single-stage AC/DC converter with the soft-switching characteristic based on interleaving technology and an LLC topology is proposed here. The converter is integrated by an interleaved cell and an LLC cell. Because the components of the system are reduced as a result of integrating, the cost decreases. Since interleaving technology is adopted, the converter can work in a high voltage input state. The LLC topology chosen here ensures that the switches on the primary side work in the ZVS condition and that the diodes on the secondary side work in the ZCS condition, which decreases the switching loss of the system. A theoretical analysis and the design procedures of the proposed converter are proposed and discussed in detail. Simulations and experimental studies with a 100W prototype are done to prove the analysis.