Effects of Input Harmonics, DC Offset and Step Changes of the Fundamental Component on Single-Phase EPLL and Elimination

Linsong Luo,Huixin Tian,Fengjiang Wu 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.4

In this paper, the expressions of the estimated information of a single-phase enhanced phase-locked loop (EPLL), when input signal contains harmonics and a DC offset while the fundamental component takes step changes, are derived. The theoretical analysis results indicate that in the estimated information, the n<SUP>th</SUP>-order harmonics cause n+1th-order periodic ripples, and the DC offset causes a periodic ripple at the fundamental frequency. Step changes of the amplitude, phase angle and frequency of the fundamental component cause a transient periodic ripple at twice the frequency. These periodic ripples deteriorate the performance of the EPLL. A hybrid filter based EPLL (HF-EPLL) is proposed to eliminate these periodic ripples. A delay signal cancellation filter is set at the input of the EPLL to cancel the DC offset and even-order harmonics. A sliding Goertzel transform-based filter is introduced into the amplitude estimation loop and frequency estimation loop to eliminate the periodic ripples caused by the residual input odd-order harmonics and step change of the input fundamental component. The parameter design rules of the two filters are discussed in detail. Experimental waveforms of both the conventional EPLL and the proposed HF-EPLL are given and compared with each other to verify the theoretical analysis and advantages of the proposed HF-EPLL.

Effects of Input Harmonics, DC Offset and Step Changes of the Fundamental Component on Single-Phase EPLL and Elimination

Luo, Linsong,Tian, Huixin,Wu, Fengjiang The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.4

In this paper, the expressions of the estimated information of a single-phase enhanced phase-locked loop (EPLL), when input signal contains harmonics and a DC offset while the fundamental component takes step changes, are derived. The theoretical analysis results indicate that in the estimated information, the n^th-order harmonics cause n+1^th-order periodic ripples, and the DC offset causes a periodic ripple at the fundamental frequency. Step changes of the amplitude, phase angle and frequency of the fundamental component cause a transient periodic ripple at twice the frequency. These periodic ripples deteriorate the performance of the EPLL. A hybrid filter based EPLL (HF-EPLL) is proposed to eliminate these periodic ripples. A delay signal cancellation filter is set at the input of the EPLL to cancel the DC offset and even-order harmonics. A sliding Goertzel transform-based filter is introduced into the amplitude estimation loop and frequency estimation loop to eliminate the periodic ripples caused by the residual input odd-order harmonics and step change of the input fundamental component. The parameter design rules of the two filters are discussed in detail. Experimental waveforms of both the conventional EPLL and the proposed HF-EPLL are given and compared with each other to verify the theoretical analysis and advantages of the proposed HF-EPLL.

중국 학술지에 게재된 독서치료 프로그램 중재 연구 동향

ZHANG LINSONG,송현종(Hyunjong Song) 한국독서치료학회 2021 독서치료연구 Vol.13 No.1

이 연구는 1990년부터 2020년 12월까지 중국에서 발표된 독서치료 관련 학술지 논문의 연구 동향을 살펴본 문헌연구이다. 중국 학술논문 데이터베이스를 통하여 독서치료 관련 학술지 논문 총 173편을 검색하고, 최종으로 중재연구 논문 28편을 선정하여 독서치료 중재연구 수의 연도별 추이, 연구참여자의 특성, 중재연구의 특징과 설계, 프로그램의 구성, 종속변인 등 5가지로 구분하여 분석하였다. 첫째, 중재연구 수의 연도별 추이에서 2017년(4편)의 연구가 가장 많았다. 둘째, 연구참여자의 특성에서 참여자의 연령대는 2~90세로 그 범주가 넓고, 참여자 유형에서 가장 많은 것은 대학생이었다. 셋째, 중재연구의 특징에서 독서치료 중재자는 제3자가 참여한 연구가, 중재장소는 학교(16편)가 가장 많았다. 연구설계에서 실험-통제집단으로 이루어진 연구가 17편, 사전-사후설계로 이루어진 연구가 25편으로 가장 많았다. 넷째, 프로그램의 구성에서 중재기간은 3개월(15편)로 정해진 연구가 가장 많았고, 중재자료는 주로 여러 종류의 도서를 혼합하여 사용하였다. 다섯째, 종속변인의 문제행동에서 정신건강(21편) 관련 논문이 가장 많았고, 효과성에서 대부분의 연구는 긍정적인 영향이 있었다고 보고하였다. 연구의 결과를 바탕으로 장애인 및 특별한 교육적 요구가 있는 사람을 연구의 참여자로 하는 연구가 많이 이루어져야 할 필요가 있고, 독서치료 관련 프로그램을 구성할 때 좀 더 체계적이고 구체적으로 할 필요가 있으며, 실제에 적합한 자료 목록이 꾸준히 연구되고 검증될 필요가 있음을 제시하였다. This research is a literature study that analyzes research trends in Bibliotherapy related academic papers published in China between 1990 and December 2020. Through the 173 Bibliotherapy related academic papers were retrieved from China s research paper database, and finally filtered out 28 of them to be analyzed. The analysis was done through 5 aspects, the annual trend of the bibliotherapy intervention s data, the characteristics of the research participants, the design and characteristics of the intervention, the program structure, and the dependent variable. The results are as follows. Firstly, among the annual trends in the number of intervention studies, the highest number of studies was conducted in 2017(4 papers). Secondly, regarding the characteristics of the research participants, there was a wide age range of the research participants, ranging from 2 to 90 years old where most of the participants were college students. Thirdly, in regard to the characteristics of the intervention, bibliotherapy, the school that had most people participating in the research and intervention as third parties(16 articles) were the most frequent study sites. In the research, the experimental control group(17 studies) had the most pretest-posttest design. Fourthly, in the structure of the program, the research of inventions lasting for 3 months(15 papers) had the most studies and the information of the intervention are mainly composed of books. Fifth, among the dependent variables, there were the most amount of research papers on mental health(21 papers). Most of the papers showed that bibliotherapy has positive effects. Based on the research results, it is necessary to carry out the research on people with disabilities and those with special educational needs. The structure of bibliotherapy needs to be more systematic and specific. There is a need for continuous research and intervention to validate the actual bibliotherapy data catalogue.

Experimental study of enhanced oil recovery with CO2 slug+N2 flood in low permeability reservoir

Baojian Du,Linsong Cheng 한국자원공학회 2014 Geosystem engineering Vol.17 No.5

Gas injection has become a significant enhanced oil recovery (EOR) measure to develop low permeability reservoirs. CO2 injection can achieve miscible displacement, but its cost is relatively high and CO2 is corrosive. N2 injection is cheap, but it is difficult to achieve miscible displacement in the formation with a limited EOR efficiency. Based on these problems, a feasibility analysis of CO2 slug+N2 to boost the recovery in low permeability reservoirs is studied through experiment. In this paper, with slim-tube test and core flood experiment, an analysis of minimum miscibility pressure, recovery of different gas injection scheme, and sensitivity of oil displacement efficiency of CO2 slug+N2 are obtained. The results show that the scheme of CO2 slug+N2 gets low miscibility pressure and can achieve miscible displacement with high ultimate recovery approximate to the scheme of continuous injection of CO2. Besides, injection timing, slug size of injected CO2, and formation pressure recovery before CO2 slug injection greatly influence the ultimate recovery. This study is significant for the understanding of EOR mechanism of CO2 slug+N2, optimization of injection parameters, and associated numerical simulation in low permeability reservoirs.

Numerical Investigation on Aerodynamic Performance and Interaction of a Lift-Offset Coaxial Rotor in Forward Flight

Haotian Qi,Ping Wang,Linsong Jiang 한국항공우주학회 2022 International Journal of Aeronautical and Space Sc Vol.23 No.2

A numerical method based on Reynolds Averaged Navier–Stokes (RANS) equations and moving overset mesh technique is developed to simulate the unsteady flow field of a rigid coaxial rotor. A high-efficient hybrid trim model is adopted to ensure the simulation accuracy of lift-offset (LOS). Cases in different advance ratios are trimmed for constant thrust coefficient and torque-balance. The effects of LOS, rotor spacing and RPM on the aerodynamic performance and interaction are analyzed. Results show that, in forward flight the lift–drag ratio can be improved by appropriate LOS. The rotor drag increases with LOS, as there is also a corresponding offset of drag. The optimum LOS varies with flight speed. At large advance ratio the interactions of the coaxial rotor are much weak, except the blade–meeting interaction. The interaction is typically illustrated by the impulsive loads of the upper blade at retreating side (270°), as the flow field is dominated by the advancing blade (90°) of the lower rotor. The interaction intensity is sensitive to LOS, rotor spacing and RPM, as it depends on the flow field gradient induced by the lower blade acting on the upper blade.

Demi-linear analysis I-basic principles

Ronglu Li,Shuhui Zhong,Linsong Li 대한수학회 2009 대한수학회지 Vol.46 No.3

The family of demi-linear mappings between topological vector spaces is a meaningful extension of the family of linear operators. We establish equicontinuity results for demi-linear mappings and develop the usual theory of distributions and the usual duality theory. The family of demi-linear mappings between topological vector spaces is a meaningful extension of the family of linear operators. We establish equicontinuity results for demi-linear mappings and develop the usual theory of distributions and the usual duality theory.

Effects of Light and Temperature on Antioxidant Activity and Peroxidase expression at Different Growth Stages of the Chinese Red Radish

Lan Wang,노광수,Li Wang,Xiaojuan Li,Linsong Wang,왕명현 한국응용생명화학회 2009 Journal of Applied Biological Chemistry (J. Appl. Vol.52 No.2

Light and temperature variations are important during the vegetative stage of the Chinese red radish. We found that peroxidase (POD) and catalase activities and the content of pelargonidin were decreased by treatments of short of light perioid and low temperatures, while the content of hydrogen peroxide was increased. The POD isoenzymes of the radish organs were detected diversely depending on the developmental stages by polyacrylamide gel electrophoresis analysis; semi-quantitative RT-PCR revealed that expression was significantly induced during the flourishing anthesis stage in the bud. These results suggest that POD expression is both timedependent and tissue-specific and that light and temperature conditions can influence the growth and antioxidant activity of the radish.

Effects of Light and Temperature on Antioxidant Activity and Peroxidase Expression at Different Growth Stages of the Chinese Red Radish

Wang, Lan,Wang, Li,Li, Xiaojuan,Wang, Linsong,Roh, Kwang-Soo,Wang, Myeong-Hyeon The Korean Society for Applied Biological Chemistr 2009 Applied Biological Chemistry (Appl Biol Chem) Vol.52 No.2

Light and temperature variations are important during the vegetative stage of the Chinese red radish. We found that peroxidase (POD) and catalase activities and the content of pelargonidin were decreased by treatments of short of light perioid and low temperatures, while the content of hydrogen peroxide was increased. The POD isoenzymes of the radish organs were detected diversely depending on the developmental stages by polyacrylamide gel electrophoresis analysis; semi-quantitative RT-PCR revealed that expression was significantly induced during the flourishing anthesis stage in the bud. These results suggest that POD expression is both time-dependent and tissue-specific and that light and temperature conditions can influence the growth and antioxidant activity of the radish.

DEMI-LINEAR ANALYSIS I-BASIC PRINCIPLES

Li, Ronglu,Zhong, Shuhui,Li, Linsong Korean Mathematical Society 2009 대한수학회지 Vol.46 No.3

The family of demi-linear mappings between topological vector spaces is a meaningful extension of the family of linear operators. We establish equicontinuity results for demi-linear mappings and develop the usual theory of distributions and the usual duality theory.

Modulation of Endogenous Peroxidase by Exogenous Peroxidase in Chinese Red Radish Seedling

Li Wang,Lan Wang,Fang-Jun Li,Linsong Wang,왕명현 한국원예학회 2011 Horticulture, Environment, and Biotechnology Vol.52 No.5

To investigate the peroxidase function and its signal pathway, activity and isozyme pattern of peroxidase and transcription level of the peroxidase gene rsprx1 and rsprx2 in Chinese red radish seedling (Raphanus sativus L.) were investigated after administration of the exogenous peroxidase (extract of radish). The activity and isozyme pattern of peroxidases were increased, among cotyledon, hypocotyl and root, the most significant increase of peroxidases activity was observed in hypocotyls, the activity of phenylalanine ammonialyase was also increased, but the pelargonidin content was decreased. Although the exogenous application of horseradish peroxidase and the extract of radish could both affect the activity of endogenous enzyme and metabolites of Chinese red radish seedlings, the latter was more effective than the former. Nifedipine, as L-calcium channel blocker, affected the activity of peroxidase and pelargonidin content in Chinese red radish seedling. Exogenously added nifedipine with the extract caused reversal of the effects. It is concluded that calcium was involved in the signal pathway of the extract of radish in Chinese red radish seedling.