A Novel Inverter Topology and its Power Balancing Optimization

Xue Bo,Gong Renxi,Liu Jianfeng,Zhang Zhiang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

Aiming at the problems of poor quality of the output voltage waveform of the existing multi-level inverters and many switching devices and DC power supplies, a novel cascadable basic unit topology is proposed. The proposed topology consists of three input DC power supplies and eight switches, forming an H half-bridge and an auxiliary bidirectional switch by adding 2 DC power supplies in the traditional H-bridge topology. The advantage of this topology is that it can be used in symmetric and asymmetric voltage source configurations, which can effectively extend the life of the inverters and reduce the production cost. The basic unit topology is cascaded in series to form a multilevel inverter topology to generate higher voltage levels, and its power balance strategy is proposed. The strategy can be described as follows: Firstly, several groups of pulse signals are generated by the traditional LS-PWM modulation strategy in which the modulation wave is compared with several groups of carriers, then a logic operation on the pulse signals is performed to obtain the drive signal of each switch, and the inverter is driven to achieve output power balance. A lot of Simulation and experiments verify the viability of the proposed topology and the effectiveness of the equalization strategy.

Quantitative Determination of Four Minor Nonvolatile Organic Acids in Beehoney by Ion-pairing Ultra Performance Liquid Chromatography-tandem Mass Spectrometry

Yun-Bo Xue,Hong-Xue Gao,Xing-An Li 한국양봉학회 2011 韓國養蜂學會誌 Vol.26 No.1

Bibliometrics-Based Analysis of the Current State of Equity Incentive Research and Cutting-Edge Trends

Sun, Xue-Bo,Gong, Chi,Liu, Peng 사회혁신기업연구원 2023 혁신기업연구 Vol.8 No.4

Competition among enterprises is becoming more and more intense, equity incentives as one of the main ways of corporate governance, is the most commonly used incentives, equity incentives is the enterprise in order to motivate and retain the core talent and the implementation of long-term incentives for employees. It is of great significance to the development of enterprises. In this paper, we use CiteSpace software to visualise and analyse the domestic research on equity incentives, mainly from the number of articles, authors, keyword clustering and keyword co-occurrence of four aspects of analysis and discussion. It is found that: the number of articles shows an upward trend; there is a lack of close cooperation between core authors; the research hotspots related to equity incentives are mainly the form of incentives, listed companies, corporate governance and corporate performance, etc. The future direction of the research is tilted towards the themes of corporate innovation and investment to explore the impact of the equity incentive approach on corporate innovation and R&D investment.

Chemical Constituents from the Aerial Parts of Isodon coetsa and their Cytotoxicity

Wei Zhao,Jian Xin Pu,Xue Du,Yong Zhao,Fei He,Hai Bo Zhang,Yong Bo Xue,Wei Lie Xiao,Han Dong Sun,Ying Li Wu,Guo Qiang Chen 대한약학회 2011 Archives of Pharmacal Research Vol.34 No.12

Three new compounds (1-3), including a neolignan, a triterpenoid, and a diterpenoid, together with twenty known compounds (4-23), were isolated from the aerial parts of Isodon coetsa. Their structures and relative configurations were elucidated on the basis of spectroscopic data. Compounds 1, 3, 5-9, 11-13, 16-17, and 19-23 were evaluated for their cytotoxicity against HT-29, BEL-7402, and SK-OV-3 human tumor cell lines. Compound 7 showed significant inhibitory effects on all three types of cells, with IC50 values of 2.52, 3.06, 2.14 μM, respectively.

Fluidity and Mechanical Properties of Open Cell AZ31 Mg Alloy Foam

( Xue Zheng Yue ),( Bo Young Hur ) 한국주조공학회 2012 한국주조공학회지 Vol.32 No.3

발포금속은 초경량 재료로서 폐기공과 개기공의 두 가지 형태의 구조를 지니고 있으며 폐기공은 내충격성, 흡음성, 단열성의 기능을 지니고 있고, 개기공은 필터, 생체지지대, 촉매재, 열방출재 등으로 사용되고 있다. 개기공발포재는 삼차원 구조모양으로 프리커서를 이용한 압력정밀주조나 기공입자용출법으로 제조하고 있으나 기공의 크기나 셀의 형상, 두께 등을 조절하기에 어려움이 있다. 이를 해결하기 위하여 환경친화적인 펄라이트를 사용하여 목적하는 크기의 그래뉼을 제조 한 후, 용융마그네슘합금을 감압주조법으로 주조하여 그래뉼의 크기로 기공율을 조절하고, 주형의 온도와 압력에 따른 유동의 길이를 측정하였다. 그래뉼 직경이 2.3 mmØ 일때에 주형의 온도300oC 이상, 압력이 5000 Pa 이상에서 유동길이6.5 cm이상을 얻었다.

A Sliding Sector Approach to Quantized Feedback Variable Structure Control

Bo-Chao Zheng,Yan-Mei Xue 제어·로봇·시스템학회 2013 International Journal of Control, Automation, and Vol.11 No.6

This paper is concerned with the quantized feedback quadratic stabilization problem for linear time-invariant systems. Sliding sector based quantized state feedback variable structure control schemes are established. The main benefit of the sliding sector technique is that it can avoid chattering caused by the utilization of variable structure control strategy. With the proposed discrete on-line adjustment of the quantization parameter, it is shown that the proposed sliding sector based sliding mode controllers can tackle state quantization and guarantee quadratic stability of the closed-loop system. Simulation results are given to verify the effectiveness of the proposed method.

Abnormal Crowd Behavior Detection Using Size-Adapted Spatio-Temporal Features

Bo Wang,Mao Ye,Xue Li,Fengjuan Zhao 제어·로봇·시스템학회 2011 International Journal of Control, Automation, and Vol.9 No.5

Abnormal crowd behavior detection is an important research issue in computer vision. However, complex real-life situations (e.g., severe occlusion, over-crowding, etc.) still challenge the effectiveness of previous algorithms. Recently, the methods based on spatio-temporal cuboid are popular in video analysis. To our knowledge, the spatio-temporal cuboid is always extracted randomly from a video sequence in the existing methods. The size of each cuboid and the total number of cuboids are determined empirically. The extracted features either contain the redundant information or lose a lot of important information which extremely affect the accuracy. In this paper, we propose an improved method. In our method, the spatio-temporal cuboid is no longer determined arbitrarily, but by the in-formation contained in the video sequence. The spatio-temporal cuboid is extracted from video se-quence with adaptive size. The total number of cuboids and the extracting positions can be determined automatically. Moreover, to compute the similarity between two spatio-temporal cuboids with different sizes, we design a novel data structure of codebook which is constructed as a set of two-level trees. The experiment results show that the detection rates of false positive and false negative are significantly reduced.

Food Microbiology and Biotechnology : Gene Cloning and Characterization of an α-Amylase from Alteromonas macleodii B7 for Enteromorpha Polysaccharide Degradation

( Xue Feng Han ),( Bo Kun Lin ),( Gan Ji Ru ),( Zhi Biao Zhang ),( Yan Liu ),( Zhong Hu ) 한국미생물 · 생명공학회 2014 Journal of microbiology and biotechnology Vol.24 No.2

Enteromorpha polysaccharides (EP) extracted from green algae have displayed a wide variety of biological activities. However, their high molecular weight leads to a high viscosity and low solubility, and therefore, greatly restrains their application. To solve this problem, bacteria from the surface of Enteromorpha were screened, and an Alteromonas macleodii strain B7 was found to be able to decrease the molecular weight of EP in culture media. Proteins harvested from the supernatant of the A. macleodii B7 culture were subjected to native gel electrophoresis, and a band corresponding to the Enteromorpha polysaccharide lyase (EPL) was detected by activity staining. The enzyme identity was subsequently confirmed by MALDI-TOF/TOF mass spectrometry as the putative α-amylase reported in A. macleodii ATCC 27126. The amylase gene (amySTU) from A. macleodii B7 was cloned into Escherichia coli, resulting in highlevel expression of the recombinant enzyme with EP-degrading activity. AmySTU was found to be cold-adapted; however, its optimal enzyme activity was detected at 40oC. The α-amylase was highly stable over a broad pH range (5.5-10) with the optimal pH at 7.5-8.0. The highest enzyme activity was detected when NaCl concentration was 2%, which dropped by 50% when the NaCl concentration was increased to 16%, showing an excellent nature of halotolerance. Furthermore, the amylase activity was not significantly affected by tested surfactants or the presence of some organic solvents. Therefore, the A. macleodii strain B7 and its α-amylase can be useful in lowering EP molecular weight and in starch processing.

Effect of structural phase transformations under pressure on electronic and optical properties of CuInS2

Bo Gao,Hong-Tao Xue,Fu-Ling Tang,Yu-Wen Cheng 한국물리학회 2017 Current Applied Physics Vol.17 No.11

First-principles plane-wave calculations were employed to study the phase transitions, electronic and optical properties of chalcopyrite CuInS2 (CIS) under pressure, which is a promising semiconductor compound material for nonlinear optical, photovoltaic and bio-applications. From the variations of Gibbs free energy and volume with pressure, we confirmed an experimentally found phase transformation of CIS from tetragonal I42d structure into the cubic Fm3m phase. It occurs at 7.9 GPa with a volume reduction of 15.6%, which are comparable with the experimental values of 9.5 GPa and 12%. A new possible phase transition of CIS from the cubic Fm3m structure to the orthorhombic Cmcm structure under higher pressure was predicted occurring at 49.6 GPa with a volume reduction about 0.64%. Using the more accurate HSE06 functional, we found that the growth rate of energy gap with pressure (dEg/dP) for the I42d phase is about 24.8 meV/GPa, very close to the experimental value of 24 meV/GPa. The calculated electronic properties for Fm3m and Cmcm phases show that CIS is a metallic material under high pressure, rather than a semiconductor. The optical absorption spectra indicate that with the increase of pressure the absorption edge of CIS becomes smaller while the optical energy gap is larger.

PARALLEL IMAGE RECONSTRUCTION FOR NEW VACUUM SOLAR TELESCOPE

Xue-Bao Li,Feng Wang,Yong Yuan Xiang,Yan-Fang Zheng,Ying Bo Liu,Hui Deng,Kai-fan Ji 한국천문학회 2014 Journal of The Korean Astronomical Society Vol.47 No.2

Many advanced ground-based solar telescopes improve the spatial resolution of observation images using an adaptive optics (AO) system. As any AO correction remains only partial, it is necessary to use post-processing image reconstruction techniques such as speckle masking or shift-and-add (SAA) to reconstruct a high-spatial-resolution image from atmospherically degraded solar images. In the New Vacuum Solar Telescope (NVST), the spatial resolution in solar images is improved by frame selection and SAA. In order to overcome the burden of massive speckle data processing, we investigate the possibility of using the speckle reconstruction program in a real-time application at the telescope site. The code has been written in the C programming language and optimized for parallel processing in a multi-processor environment. We analyze the scalability of the code to identify possible bottlenecks, and we conclude that the presented code is capable of being run in real-time reconstruction applications at NVST and future large aperture solar telescopes if care is taken that the multi-processor environment has low latencies between the computation nodes.