A Compensation Method of Dead-Time and Forward Voltage Drop for Inverter Operating at Low Frequency

Lingyun Zhao,Wenxiang Song,Jiuyi Feng 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.2

The dead-time is introduced to prevent the upper and lower power devices of the same leg from conducting simultaneously. However, it will cause the actual output voltage deviate from the desired voltage and the load current distortion will occur, which is especially unexpected when the inverter operates at a low frequency. In addition, a voltage drop is produced when the current fl ows through the power device, which further aggravates the current distortion. This paper presents a simple compensation strategy for the dead-time and the forward voltage drop. The current polarity is obtained accurately by fi ltering the three-phase currents in the synchronous rotating coordinate. The driving signals in the SVPWM is adjusted according to the current polarity to compensate the dead-time. The forward voltage drops are equivalent to an error voltage vector by using the approximate average threshold voltage and average diff erential resistance model, which is added to the given voltage to suppress the eff ects of the forward voltage drops. The compensation quantities are set to change based on a piece wise linear function to eliminate the occurrence of the current clamp and the instantaneous zero-crossing switch. Finally, the proposed compensation strategy is verifi ed by the simulation and experiment.

Promoting the modernization of community governance based on emotional management of network media in public events

Zhao Lingyun,Chen Xi 한중경제문화학회 2021 한중경제문화연구 Vol.16 No.-

A real-time sorting algorithm for in-beam PET of heavy-ion cancer therapy device

Ke, Lingyun,Yan, Junwei,Chen, Jinda,Wang, Changxin,Zhang, Xiuling,Du, Chengming,Hu, Minchi,Yang, Zuoqiao,Xu, Jiapeng,Qian, Yi,She, Qianshun,Yang, Haibo,Zhao, Hongyun,Pu, Tianlei,Pei, Changxu,Su, Hong Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.10

A real-time digital time-stamp sorting algorithm used in the In-Beam positron emission tomography (In-Beam PET) is presented. The algorithm is operated in the field programmable gate array (FPGA) and a small amount of registers, MUX and memory cells are used. It is developed for sorting the data of annihilation event from front-end circuits, so as to identify the coincidence events efficiently in a large amount of data. In the In-Beam PET, each annihilation event is detected by the detector array and digitized by the analog to digital converter (ADC) in Data Acquisition Unit (DAQU), with a resolution of 14 bits and sampling rate of 50 MS/s. Test and preliminary operation have been implemented, it can perform a sorting operation under the event count rate up to 1 MHz per channel, and support four channels in total, count rate up to 4 MHz. The performance of this algorithm has been verified by pulse generator and ²²Na radiation source, which can sort the events with chaotic order into chronological order completely. The application of this algorithm provides not only an efficient solution for selection of coincidence events, but also a design of electronic circuit with a small-scale structure.

Atorvastatin regulates the migration and invasion of prostate cancer through the epithelial-mesenchymal transformation and matrix metalloproteinase pathways

Zhanmeng Zhu,Yin Cao,Lingyun Liu,Zhiyi Zhao,Hongyu Yin,Hongliang Wang 대한비뇨의학회 2022 Investigative and Clinical Urology Vol.63 No.3

Purpose: Our purpose was to verify the effects of atorvastatin (ATO) on prostate cancer (PCa) proliferation, apoptosis, invasion, and metastasis and to further explore the drug’s mechanism of action. Materials and Methods: We used cell counting kit-8 (CCK8) and clone formation experiments to study the effect of ATO on the proliferation of PC3 cells. Flow cytometry and Hoechst 33342 staining were used to detect cell apoptosis. Cell migration and invasion were detected through wound healing experiments and transwell experiments. Western blotting was applied to detect apoptosis-related proteins (BAX, Bcl-2, PARP, and Caspase-3), epithelial-mesenchymal transformation (EMT) proteins, and matrix metalloproteinase (MMP) expression. A mouse xenograft tumor model was established, and tumor volume and weight were determined. The expression levels of the above-mentioned proteins were determined through western blot. Results: ATO inhibited PC-3 cell proliferation and promoted cell apoptosis in a dose-dependent manner. ATO significantly up-regulated the expression of BAX, PARP, and Caspase-3 and inhibited the expression of Bcl-2. Wound healing and transwell experiments showed that ATO inhibited invasion and metastasis in PC-3 cells, possibly because ATO could inhibit the EMT and the expression of MMPs in PC-3 cells. Studies in nude mice showed that ATO significantly reduced tumor volume and weight; the expression levels of related proteins were consistent with the in vitro results. Conclusions: ATO inhibits the occurrence and development of PCa and regulates the migration and invasion of PCa cells by inhibiting the EMT and MMPs.

Characteristics and significance of heterogeneity of sea−land transitional facies shale gas reservoir in North Guizhou, China

Ran Wang,Shuxun Sang,Jun Jin,Lingyun Zhao,Wei Gao,Wei Fu,Fulun Shi,Ende Deng 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.1

In order to identify the characteristics of the longitudinal heterogeneity of the sea–land transitional facies shale gas reservoir in the upper Yangtze region of North Guizhou, studies on the lithological combination, rock and mineral composition, geochemical parameters and reservoir microanisotropy characteristics of Longtan Formation in the study area are conducted on the basis of core observation, testing of geochemistry and reservoir physical property and well logging interpretation. The studies show that the lithological assemblages of the Longtan Formation are diverse and form an amina interbedding of “sand-mud-coal” with obvious cyclicity characteristics. There is a large longitudinal difference in rock and mineral composition and the average mass fraction of the clay mineral is 39.83%, which is obviously higher than that of the marine shale in North America and South China; the longitudinal heterogeneity of the organic matter abundance is high, with an average of 2.17% in the upper part, and 4.51% in the lower part; in accordance with the results observed with the scanning electron microscope and results calculated through pore fractal, the microscopic pore heterogeneity of the reservoir is high. The comparison and analysis of connecting wells with different scales in the study area show that the control effect of the depositional environment on longitudinal macroscopic heterogeneity of Longtan Formation is obvious, and the longitudinal microscopic heterogeneity is controlled through diagenesis. Meanwhile, studies with main coal mining seam as the seam section division method conclude that the heterogeneity of Coal Seam Sections 4 to 5 and Coal Seam Sections 13 to 15 is significantly smaller than that in other seam sections, and the Coal Seam Sections 4 to 5 and Coal Seam Sections 13 to 15 can be considered as a priority key seam section during development of shale gas.

Beyond Canonical PROTAC: Biological targeted protein degradation (bioTPD)

Huifang Wang,Runhua Zhou,Fushan Xu,Kongjun Yang,Liuhai Zheng,Pan Zhao,Guangwei Shi,Lingyun Dai,Chengchao Xu,Le Yu,Zhijie Li,Jianhong Wang,Jigang Wang 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Targeted protein degradation (TPD) is an emerging therapeutic strategy with the potential to modulate disease associated proteins that have previously been considered undruggable, by employing the host destructionmachinery. The exploration and discovery of cellular degradation pathways, including but not limited toproteasomes and lysosome pathways as well as their degraders, is an area of active research. Since the conceptof proteolysis-targeting chimeras (PROTACs) was introduced in 2001, the paradigm of TPD has been greatlyexpanded and moved from academia to industry for clinical translation, with small-molecule TPD being particularlyrepresented. As an indispensable part of TPD, biological TPD (bioTPD) technologies including peptide-, fusionprotein-, antibody-, nucleic acid-based bioTPD and others have also emerged and undergone significantadvancement in recent years, demonstrating unique and promising activities beyond those of conventional small molecule TPD. In this review, we provide an overview of recent advances in bioTPD technologies, summarize theircompositional features and potential applications, and briefly discuss their drawbacks. Moreover, we present somestrategies to improve the delivery efficacy of bioTPD, addressing their challenges in further clinical development.

Evaluation of energy correction algorithm for signals of PET in heavy-ion cancer therapy device

Niu, Xiaoyang,Yan, Junwei,Wang, Xiaohui,Yang, Haibo,Ke, Lingyun,Chen, Jinda,Du, Chengming,Zhang, Xiuling,Zhao, Chengxin,Kong, Jie,Su, Hong Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.1

In order to solve the contradiction between requirements of high sampling rate for acquiring accurate energy information of pulses and large amount of data to be processed timely, the method with an algorithm to correct errors caused by reducing the sampling rate is normally used in front-end read-out system, which is conductive to extract accurate energy information from digitized waveform of pulse. The functions and effects of algorithms, which mainly include polynomial fitting with different fitting times, double exponential function fitting under different sampling modes, and integral area algorithm, are analyzed and evaluated, and some meaningful results is presented in this paper. The algorithm described in the paper has been used preliminarily in a prototype system of Positron Emission Tomography (PET) for heavy-ion cancer therapy facility.