A SiC MOSFET‑based parallel multi‑inverter inductive power transfer (IPT) system

Qiang Bo,Lifang Wang,Yuwang Zhang 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.6

A parallel multi-inverter inductive power transfer (IPT) system based on SiC MOSFETs is presented to upgrade the power level and to suppress the circulating current. First, the basic principle and a mathematical model of a parallel multi-inverter IPT system are analyzed, and the output current and power for each of the parallel inverters are modeled. Second, the compensation network parameters for the parallel multi-inverter IPT system are confi gured and a cooperative control strategy is given. Third, various circulating loops and zero-voltage-switching (ZVS) operation are studied. Finally, a 1.2 kW IPT system is built for experimental verifi cation. Results obtained with the experimental system demonstrate that the output power ratio for each of the parallel inverters is about 1:2 and all of them achieve ZVS. In addition, the maximum effi ciency of the DC–DC system is measured to be 92.53%, while the circulating current amplitude is only 0.2 A.

MicroRNA-214-mediated UBC9 expression in glioma

( Zhi Qiang Zhao ),( Xiao Chao Tan ),( Ani Zhao ),( Li Yuan Zhu ),( Bin Yin ),( Jiang Ang Yuan ),( Bo Qin Qiang ),( Xiao Zhong Peng ) 생화학분자생물학회(구 한국생화학분자생물학회) 2012 BMB Reports Vol.45 No.11

It has been reported that ubiquitin-conjugating enzyme 9 (Ubc9), the unique enzyme2 in the sumoylation pathway, is up-regulated in many cancers. However, the expression and regulation of UBC9 in glioma remains unknown. In this study, we found that Ubc9 was up-regulated in glioma tissues and cell lines compared to a normal control. UBC9 knockdown by small interfering RNA (siRNA) affected cell proliferation and apoptosis in T98G cells. Further experiments revealed that microRNA (miR)-214 directly targeted the 3` untranslated region (UTR) of UBC9 and that there was an inverse relationship between the expression levels of miR-214 and UBC9 protein in glioma tissues and cells. MiR-214 overexpression suppressed the endogenous UBC9 protein and affected T98G cell proliferation. These findings suggest that miR-214 reduction facilitates UBC9 expression and is involved in the regulation of glioma cell proliferation.

Research Cage Wind Turbines’ Dynamic Characteristics Based on Time-varying Parameters

Gu Bo,Liu Yongqian,Xu Qiang,Kang Shun 보안공학연구지원센터 2014 International Journal of Control and Automation Vol.7 No.10

According to the characteristics of cage wind turbines’ dynamic characteristics which change following the wind speed changes, the dynamic mathematical models of cage wind turbines major subsystems have been established, including the aerodynamic subsystem model, drive train subsystem model and generator subsystem model. Then these nonlinear dynamic models with time-varying parameters have been integrated and linearized to obtain the whole linear time-varying parameters dynamic mathematical model. To take the 2MW cage wind turbines wind turbine as example, the proposed model is validated by the study on the dynamic characteristics of cage wind turbines with wind speed variation , and the results show that the proposed model could provide a theoretical support for optimal control of the cage wind turbines.

Impact of WS2 Nanoparticles on Nitrile Butadiene Rubber Properties

Qiang He,Guangfei Wang,Bo Zheng,Wei Zhou,Yanbin Zhang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.5

WS2/nitrile butadiene rubber (NBR) nanocomposite was prepared by mechanical blending. The vulcanization andmechanical behavior, contact angle with water, friction and wear properties, as well as thermal stability were measured toinvestigate the influence of nano WS2 content on the NBR. Moreover, scanning electron microscopic (SEM) and elementdispersive spectrum analysis (EDS) were used to analyze the tensile failure mechanism of the WS2/NBR nanocomposite. Results showed that the tensile strength, elongation at break and contact angle with water of the vulcanized rubber reachedtheir maxima when the content of nano WS2 was 10 parts. Furthermore, fast vulcanization rate and the minimum friction andwear properties were also observed. The tear strength, rebound resilience and electrical resistivity decreased with theincrement of WS2 content, while the hardness and thermal stability increased. Investigation on tensile fracture showed thatcrack growth was mainly caused by stress concentration.

The Uneven Distribution of Mating Type Genes in Natural and Cultivated Truffle Orchards Contributes to the Fructification of Tuber indicum

( Qiang Li ),( Yu Fu ),( Qun Sun ),( Pierre Sourzat ),( Mei Yang ),( Chengyi Liu ),( Hao Tan ),( Lei Ye ),( Jie Zou ),( Chenguang Wu ),( Bo Zhang ),( Xiaolin Li ) 한국균학회 2018 Mycobiology Vol.46 No.1

The aim of this study was to investigate the pattern of distribution of mating type (MAT) genes of Tuber indicum in ectomycorhizosphere soils from natural T. indicum-producing areas and cultivated truffle orchards and ascocarp samples from different regions. Quantitative real-time PCR and multiplex PCR were used to weight the copy numbers of MAT1-1-1 and MAT1-2-1 in natural truffle soils and cultivated orchard soils. The effect of limestone on the pattern of truffle MAT genes and the correlation between soil properties and the proportion of MAT genes were also assessed. These results indicated that an uneven and nonrandom distribution of MAT genes was common in truffle-producing areas, cultivated truffle orchards, and ascocarps gleba. The competition between the two mating type genes and the expansion of unbalanced distribution was found to be closely related to truffle fructification. Limestone treatments failed to alter the proportion of the two mating type genes in the soil. The content of available phosphorus in soil was significantly correlated with the value of MAT1-1-1/MAT1-2-1 in cultivated and natural ectomycorhizosphere soils. The application of real-time quantitative PCR can provide reference for monitoring the dynamic changes of mating type genes in soil. This study investigates the distributional pattern of T. indicum MAT genes in the ectomycorhizosphere soil and ascocarp gleba from different regions, which may provide a foundation for the cultivation of T. indicum.

Dynamic characteristics of the cavitation clouds of submerged Helmholtz self-sustained oscillation jets from high-speed photography

Qiang Wu,Wei Wei,Bo Deng,Pan Jiang,Deng Li,Mengda Zhang,Zhenlong Fang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.2

Experiments were conducted to investigate the cavitation behavior of Helmholtz self-sustained oscillation jets. In this paper, highspeed photographic technology was used to capture the flow details of cavitation with various nozzle structures and operating pressures from 1.0 MPa to 3.0 MPa. Furthermore, an in-house code based on a matrix approach that processes gray values with various statistical methods was used to quantitatively evaluate the cavitation jet of waters generated by Helmholtz nozzles. The mean values of the normalized gray levels of the images were used as a metric to measure the lengths of the cavitation clouds. When the original data were smoothed by a 15th lowess filter to exclude the noise of the images, the periods of cavitation cloud shedding were obtained accordingly, and the average period had a magnitude of 10 -4 . All of the smoothed results of the original data captured a two-peak shape that comprises a large peak and a mild hump. Image processing results showed that the Helmholtz nozzle produced greater cavitation intensity than a traditional conical nozzle. The shear-layer instability waves disappeared within 10d 1 downstream from the injector exit. The cavitation clouds propagated a distance of approximately 1–10d 1 at various pressure ratios, and the clouds were continuous within this distance. The geometry of the nozzle strongly affected the length and shedding period of the cavitation cloud. As described in the discussion section of this paper, when the cavity length was doubled, the length of the cavitation cloud decreased approximately 26.5 %; however, the period of the cavitation cloud shedding increased approximately 10 %. The longest cavitation cloud appeared when the ratio of the cavity diameter and the upper nozzle diameter was eight. Excessively small or large diameters were not conducive to the development of cavitation, whereas the effect of the pressure ratio on the cavitation cloud length was positive. When other conditions remained unchanged, the lump shedding period decreased as the pressure ratio was increased to 25. When the pressure ratio exceeded 25, the cavitation cloud shedding period remained constant.

Elevating Limonene Production in Oleaginous Yeast Yarrowia lipolytica via Genetic Engineering of Limonene Biosynthesis Pathway and Optimization of Medium Composition

Bo-Qian Cheng,Liu-Jing Wei,Yu-Bei Lv,Jun Chen,Qiang Hua 한국생물공학회 2019 Biotechnology and Bioprocess Engineering Vol.24 No.3

As an alternative terpenoid producer, nonconventional oleaginous yeast Yarrowia lipolytica was chosen for limonene production. Y. lipolytica can give high biomass yield and metabolize a broad range of substrates such as glycerol, alkanes, fatty acid, fats, and oils. As previously reported, optimization of limonene synthesis pathway and mevalonate (MVA) pathway leads to the accumulation of 112-fold higher limonene as compared to an initial strain. In this study, we introduced an additional copy of limonene synthesis gene (LS), which resulted in an increase of limonene production. This engineered strain was used to carry out further optimization study. Amongst all the carbon sources tested, the highest level of limonene production was obtained from glycerol, and citrate was selected as an auxiliary carbon source. In fed-batch fermentation with an optimized medium, the engineered strain was found to produce 165.3 mg/L limonene, which corresponds to the highest yield till date for the production of limonene in Y. lipolytica.

Four-port Hydraulic Transformer with Inlet and Outlet Equal Flow and Its Efficiency Characteristics

Qiang Liu,Lianquan Zhou,Xiaonan Bo,Chu Zhang 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.2

In order to avoid throttling loss and recover differential pressure energy, braking energy and gravitational potential energy without changing the original hydraulic system, the four-port hydraulic transformer (FHT) is proposed. Its theoretical and experimental efficiency characteristics are researched. The basic structure and principle of the FHT are explained. Besides, the mathematical model of its efficiency is established. The results show that the pressure ratio can be changed by adjusting the control angle of valve plate, and the efficiency characteristics of the FHT match the efficiency characteristics of the hydraulic pump/motor. The total efficiency increases first and decreases afterwards with the increment of cylinder speed, and increases with the control angle of valve plate, while decreases with the recycling pressure difference.

Containment Control of Multi-agent Systems with Time-delays over Heterogeneous Networks

Bo Li,Hong-yong Yang,Zeng-qiang Chen,Zhong-Xin Liu 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.10

Containment control problems for second-order multi-agent systems with fixed communication timedelays under heterogeneous networks topologies are investigated. Based on Lyapunov-Krasovskii functional method and the linear matrix inequality (LMI) method, sufficient conditions on the communication digraph, the feedback gains, and the allowed upper bound of the time-delays to ensure containment control of the multi-agent systems using the different containment control algorithms are given. Finally, numerical simulations are presented to demonstrate theoretical results.

Experimental study on seismic behavior of reinforced concrete column retrofitted with prestressed steel strips

Bo Zhang,Yong Yang,Yuan-feng Wei,Ru-yue Liu,Chu Ding,Ke-qiang Zhang 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.6

In this study, a new retrofitting method for improving the seismic performance of reinforced concrete column was presented, in which prestressed steel strips were utilized as retrofitting stuff to confine the reinforced concrete column transversely. In order to figure out the seismic performance of concrete column specimen retrofitted by such prestressed steel strips methods, a series of quasi-static tests of five retrofitted specimens and two unconfined column specimen which acted as control specimens were conducted. Based on the test results, the seismic performance including the failure modes, hysteresis performance, ductility performance, energy dissipation and stiffness degradation of all these specimens were fully investigated and analyzed. And furthermore the influences of some key parameters such as the axial force ratios, shear span ratios and steel strips spacing on seismic performance of those retrofitted reinforced concrete column specimens were also studied. It was shown that the prestressed steel strips provided large transverse confining effect on reinforced concrete column specimens, which resulted in improving the shearing bearing capacity, ductility performance, deformation capacity and energy dissipation performance of retrofitted specimens effectively. In comparison to the specimen which was retrofitted by the carbon fiber reinforced plastics (CFRP) strips method, the seismic performance of the specimens retrofitted by the prestressed steel strips was a bit better, and with much less cost both in material and labor. From this research results, it can be concluded that this new retrofitting method is really useful and has significant advantages both in saving money and time over some other retrofitting methods.