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Study on Half-Bridge Voltage Balancing Circuit with Two Driving Methods
Zhang Xianjin,Zhu Hairong,Wu Di,Li Rui 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3
A voltage balancing circuit not only can split a two-wire dc grid into a three-wire dc grid, but also can balance the voltages of series capacitors or battery packs. A half-bridge voltage balancing circuit is a simpler topology and is widely introduced. But it has not been deeply analysed. Thus, in this paper the balancing circuit with the complementary driving method is studied in detail, fi rstly. Secondly, for avoiding the reactive current occurred in the complementary driving method, the unipolar current driving method is also proposed. Finally, the prototype is implemented in the lab, and the simulation and experimental results verify the analyses.
Study on Interleaved Three-Switch Buck-Boost Converters with Co-directional Coupling Inductor
Zhang Xianjin,Ma Wenjing,Zhu Hairong,Wu Di,Bi Shubo 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1
In order to obtain soft switching and simplify the controlling circuit of an interleaved two-switch Buck-Boost converter, two types of three-switch interleaved Buck-Boost converters are proposed in this paper. Firstly, this paper analyses the coupling process of the presented converters under a large coupling coefcient. Then, the operating principle of the two converters is given in detail. And it is concluded that the expended duty cycle and soft switching of most of power devices can be obtained and a sharing-current circuit is also not needed. This will deeply simplify the controlling circuit. Finally, the simulation and experimental results verify the analysis.
Study of thermoacoustic oscillations in half-open tubes for saturated superfluid helium
Xianjin Wang,Xiaofei Niu,Feng Bai,Junhui Zhang,Shuping Chen 한국초전도저온학회 2022 한국초전도저온공학회논문지 Vol.24 No.3
Thermoacoustic oscillations (TAOs) are spontaneous pressure oscillations frequently seen in hydrogen or helium cryogenicsystems. Half-open tubes connected to cryogenic fluid with a closed room temperature end have a high potential for oscillationgeneration. Thermoacoustic oscillations will result in significant pressure fluctuations and additional heat load, endangering thesecurity and stability of the cryogenic system. The goal of this paper is to investigate TAOs in superfluid helium using boththeoretical and experimental methods. Five half-open tubes with varied typical inner diameters inserted into superfluid helium wereinstalled in a test cryostat. The onset characteristics of thermoacoustic oscillations were presented and studied. The effect oftemperature profile was discussed. Finally, a simple eliminating method was introduced.
Lu Yang,Ying Zhang,Xianjin Hu,Bing-Chiuan Shiu,Ching-Wen Lou,Jia-Horng Lin,Ting-Ting Li 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.120 No.-
Drug-resistant pathogens pose significant pressures and challenges for medical protective materials withhighly effective antibacterial/antiviral and rechargeable properties. In this study, a clean, rechargeablephotodynamic antibacterial/antiviral strategy was proposed after nanofibrous membranes were graftedby photosensitive 4,4, -terephthalic di-phthalic anhydride (TDPA) and natural polyphenol chlorogenicacid (CA) antibacterial agent. The resultant membrane released the maximumOH and H2O2 capacitiesof 6188.56 lg/g and 842.00 lg/g, respectively, exhibited the storage antibacterial stability even storedfor 30 days in the dark. After seven quenching, the charging capacity retained more than 70% of the original. The antibacterial efficiency of the membrane showed more than 99%. In addition, the antibacterialefficiency decreased by only 3% after water washing. Moreover, it demonstrated an excellent antiviralproperty whose antiviral activity against H3N2 achieved 3.6 PFU/mL. This daylight-driven rechargeablenanofibrous membrane can be used to develop reusable medical protective materials with rechargeableantibacterial and antiviral efficiency.
Assessment of phenanthrene bioavailability in aged and unaged soils by mild extraction.
Khan, Muhammad Imran,Cheema, Sardar Alam,Shen, Chaofeng,Zhang, Congkai,Tang, Xianjin,Shi, Jiyan,Chen, Xincai,Park, Joonhong,Chen, Yingxu D. Reidel Pub. Co ; Springer 2012 Environmental monitoring and assessment Vol.184 No.1
<P>It has become apparent that the threat of an organic pollutant in soil is directly related to its bioavailable fraction and that the use of total contaminant concentrations as a measure of potential contaminant exposure to plants or soil organisms is inappropriate. In light of this, non-exhaustive extraction techniques are being investigated to assess their appropriateness in determining bioavailability. To find a suitable and rapid extraction method to predict phenanthrene bioavailability, multiple extraction techniques (i.e., mild hydroxypropyl-β-cyclodextrin (HPCD) and organic solvents extraction) were investigated in soil spiked to a range of phenanthrene levels (i.e., 1.12, 8.52, 73, 136, and 335?μg?g(?-?1) dry soil). The bioaccumulation of phenanthrene in earthworm (Eisenia fetida) was used as the reference system for bioavailability. Correlation results for phenanthrene suggested that mild HPCD extraction was a better method to predict bioavailability of phenanthrene in soil compared with organic solvents extraction. Aged (i.e., 150?days) and fresh (i.e., 0?day) soil samples were used to evaluate the extraction efficiency and the effect of soil contact time on the availability of phenanthrene. The percentage of phenanthrene accumulated by earthworms and percent recoveries by mild extractants changed significantly with aging time. Thus, aging significantly reduced the earthworm uptake and chemical extractability of phenanthrene. In general, among organic extractants, methanol showed recoveries comparable to those of mild HPCD for both aged and unaged soil matrices. Hence, this extractant can be suitable after HPCD to evaluate risk of contaminated soils.</P>