A New Theoretical Equation to Estimate Poisson’s Ratio for Coated Bi-axial Warp Knitted Fabrics under Bias Tensile Loading

Jianwen Chen,Han Zhou,Bing Zhao,Wujun Chen,Mingyang Wang,Zhihong Xu 한국섬유공학회 2018 Fibers and polymers Vol.19 No.12

Tensile tests of seven bias angles with a 15 o increment with respect to the warp direction are conducted on a typical coated bi-axial warp knitted fabric (BWKF). By utilizing the Digital Image Correlation technique, the experimental results are processed, and detailed responses of strain contours and Poisson’s ratios are determined for some specific strain levels, and an extraordinary M-shaped relationship between Poisson’s ratio and bias angle is revealed. Then, the tested Poisson’s ratios are compared with corresponding theoretical predictions from the original theory for ordinary anisotropic materials, discrepancies and their possible causes are analyzed. Finally, the original theory used for Poisson’s ratio predication of ordinary anisotropic materials is modified for application to the BWKFs by considering the unique local valley at 45 o caused by structural differences and possible yarn movements. The modified theoretical equation could exhibit the Mshaped relationship between Poisson’s ratio and bias angle, and is validated due to the high similarity between the predictions and experimental results. This investigation could provide some new insights into the orientation-dependence, Poisson’s effect and complex deformation mechanism of BWKFs.

Fluctuation Power Control Strategy for MMC-based SST to Reduce the Submodule Capacitor Voltage Oscillation

Xiaolong Cai,Jianwen Zhang,Gang Shi,Xu Cai,Jianqiao Zhou,Zhuyong Li,Jiacheng Wang,Jiajie Zang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

In the future AC-DC hybrid distribution system, solid state transformer (SST) will take place of conventional transformer, as it could reduce the weight and volume of transformer, and achieve voltage and current regulation, power flow control, power quality enhancement. MMC-based SST is a novel SST topology, which could provide the MVDC port. However, the excessive bulky submodule capacitors limits this topology into practical application. This paper proposes a fluctuation power control strategy for MMC-based SST to reduce the submodule capacitor voltage oscillation, which could optimize the capacitance and reduce the volume and cost of capacitor. The feasibility of this proposed method is verified by MATLAB simulation.

MPC-based Two-stage Rolling Power Dispatch Approach for Wind-integrated Power System

Zhai, Junyi,Zhou, Ming,Dong, Shengxiao,Li, Gengyin,Ren, Jianwen The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

Regarding the fact that wind power forecast accuracy is gradually improved as time is approaching, this paper proposes a two-stage rolling dispatch approach based on model predictive control (MPC), which contains an intra-day rolling optimal scheme and a real-time rolling base point tracing scheme. The scheduled output of the intra-day rolling scheme is set as the reference output, and the real-time rolling scheme is based on MPC which includes the leading rolling optimization and lagging feedback correction strategy. On the basis of the latest measured thermal unit output feedback, the closed-loop optimization is formed to correct the power deviation timely, making the unit output smoother, thus reducing the costs of power adjustment and promoting wind power accommodation. We adopt chance constraint to describe forecasts uncertainty. Then for reflecting the increasing prediction precision as well as the power dispatcher's rising expected satisfaction degree with reliable system operation, we set the confidence level of reserve constraints at different timescales as the incremental vector. The expectation of up/down reserve shortage is proposed to assess the adequacy of the upward/downward reserve. The studies executed on the modified IEEE RTS system demonstrate the effectiveness of the proposed approach.

System Parameter Design Method Based on a Serial-Shunt Type Soft Normally Open Point

Haohua Peng,Jianwen Zhang,Jianqiao Zhou,Gang Shi,Xu Cai,Mingyang Yang,Zhuyong Li 전력전자학회 2023 ICPE(ISPE)논문집 Vol.2023 No.-

The soft normally-open point (SNOP) has been proposed as a solution to address issues stemming from new energy generation and other factors. One of the primary topologies for implementing SNOP is the back-to-back voltage converter (BTB-VSC). However, this approach suffers from several drawbacks, including low efficiency, a large volume, and limited control freedom degrees. To overcome these limitations, we propose a new serial-shunt type soft normally open point (SS-SNOP). To achieve better regulation capability, it is crucial to develop a parameter design method related to system parameters. In this paper, a design method is presented for a set of necessary parameters, such as inductors, capacitors, power devices, and so on. Simulation results confirm the effectiveness of the proposed system parameter design method. Overall, the SS-SNOP topology and the proposed parameter design method offer a promising solution for addressing issues related to new energy generation and other factors.

Olaparib induced senescence under P16 or P53 dependent manner in ovarian cancer

Zehua Wang,Jianwen Gao,Jiabing Zhou,Haiou Liu,Congjian Xu 대한부인종양학회 2019 Journal of Gynecologic Oncology Vol.30 No.2

Objective: Poly (ADP-ribose) polymerase (PARP) is an important molecule in the early stress response of DNA damage, which is involved in DNA damage repair and cellular senescence. Olaparib, as PARP inhibitor, has an anti-tumor effect on high grade serous ovarian cancer, but its effects on cellular senescence have not been reported. This study intends to explore the role of olaparib in the regulation of senescence in ovarian cancer cells. Methods: The effects of olaparib on the senescence of ovarian cancer cells were detected by using the senescence-associated β-galactosidase (SA-β-Gal) and senescence-associated heterochromatin aggregation (SAHF). Quantitative real-time polymerase chain reaction was used to analyze the senescence-associated secretory phenotype (SASP). Cell cycle and apoptosis were detected by flow cytometry. The effect of olaparib on tumor growth was analyzed in a nude mouse xenograft transplantation model. Results: Long-term (6 days) treatment with olaparib (5 μM) significantly inhibited the growth of ovarian cancer cells, leading to arrest the cell cycle at G0/G1 phase, significant increase the number of positive SA-β-Gal stained cells and positive SAHF cells. The expression of P16 and retinoblastoma protein (p-RB) were significantly enhanced in SKOV3 cells under olaparib treated, meanwhile, the expression of P53 and p-RB were upregulated in A2780 cells. In OVCAR-3 cells, the expression of P53 was downregulated and p-RB was upregulated. Mice with SKOV3 xenograft transplantation was given olaparib (10 mg/kg/day) via abdominal cavity administration, the tumor volume was reduced (p<0.01). Conclusion: Continuous low dosage administration of olaparib induced senescence under P16 or P53 dependent manner in ovarian cancer.

A bi-directional valveless piezoelectric micropump based on the Coanda effect

Zheng Zhang,Lipeng He,Jianwen Zhou,Dianbin Hu,Yi Hou,Guangming Cheng 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2

In this paper, the hydrodynamic characteristics of a piezoelectric micropump operate on the Coanda effect, and the mechanism of bi-directional pumping are analyzed by numerical simulation and experiments. The research focuses on the different positions of the fluid deflector and the influence on the output of the micropump. The results show that a closer fluid deflector to the inlet can produce greater vortices in the suction process due to the Coanda effect, and the backflow diminishing is more significant as well. Moreover, the different positions of the fluid deflector can cause a phenomenon that the micropump will achieve bi-directional pumping. As a finding, vortices arranged in pairs could improve the rectification efficiency of the micropump. The micropump achieves a maximum flow rate of 40.5 ml/min and back pressure of 5.76 cmH 2 o. In addition, the maximum flow rate per unit area can reach 305.2 μl/(min mm 2 ).

Autonomous exploration for radioactive sources localization based on radiation field reconstruction

Xulin Hu,Junling Wang,Jianwen Huo,Ying Zhou,Yunlei Guo,Li Hu Korean Nuclear Society 2024 Nuclear Engineering and Technology Vol.56 No.4

In recent years, unmanned ground vehicles (UGVs) have been used to search for lost or stolen radioactive sources to avoid radiation exposure for operators. To achieve autonomous localization of radioactive sources, the UGVs must have the ability to automatically determine the next radiation measurement location instead of following a predefined path. Also, the radiation field of radioactive sources has to be reconstructed or inverted utilizing discrete measurements to obtain the radiation intensity distribution in the area of interest. In this study, we propose an effective source localization framework and method, in which UGVs are able to autonomously explore in the radiation area to determine the location of radioactive sources through an iterative process: path planning, radiation field reconstruction and estimation of source location. In the search process, the next radiation measurement point of the UGVs is fully predicted by the design path planning algorithm. After obtaining the measurement points and their radiation measurements, the radiation field of radioactive sources is reconstructed by the Gaussian process regression (GPR) model based on machine learning method. Based on the reconstructed radiation field, the locations of radioactive sources can be determined by the peak analysis method. The proposed method is verified through extensive simulation experiments, and the real source localization experiment on a Cs-137 point source shows that the proposed method can accurately locate the radioactive source with an error of approximately 0.30 m. The experimental results reveal the important practicality of our proposed method for source autonomous localization tasks.

MPC-based Two-stage Rolling Power Dispatch Approach for Wind-integrated Power System

Junyi Zhai,Ming Zhou,Shengxiao Dong,Gengyin Li,Jianwen Ren 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.2

Regarding the fact that wind power forecast accuracy is gradually improved as time is approaching, this paper proposes a two-stage rolling dispatch approach based on model predictive control (MPC), which contains an intra-day rolling optimal scheme and a real-time rolling base point tracing scheme. The scheduled output of the intra-day rolling scheme is set as the reference output, and the real-time rolling scheme is based on MPC which includes the leading rolling optimization and lagging feedback correction strategy. On the basis of the latest measured thermal unit output feedback, the closed-loop optimization is formed to correct the power deviation timely, making the unit output smoother, thus reducing the costs of power adjustment and promoting wind power accommodation. We adopt chance constraint to describe forecasts uncertainty. Then for reflecting the increasing prediction precision as well as the power dispatcher’s rising expected satisfaction degree with reliable system operation, we set the confidence level of reserve constraints at different timescales as the incremental vector. The expectation of up/down reserve shortage is proposed to assess the adequacy of the upward/downward reserve. The studies executed on the modified IEEE RTS system demonstrate the effectiveness of the proposed approach.

Parameter Design Scheme for the embedded Multiport Flexible ac Interconnector

Hongming Li,Jianqiao Zhou,Jianwen Zhang,Xu Cai,Yuwen Liu,Mingyang Yang,Jiajie Zang 전력전자학회 2023 ICPE(ISPE)논문집 Vol.2023 No.-

The softly open point (SOP) is a burgeoning technology to deal with the potential voltage violation and feeder congestion issues yielded by the increasing integration of distributed generations (DGs) and various novel loads. Compared with the traditional solution with the back-to-back modular multilevel converters (BTB-MMC), a novel embedded multiport flexible ac interconnector (eM-FACI) is proposed to serve as the SOP for the feeders’ power regulation with light weight, small volume, and low cost. Flexible multi-feeder interconnection can be achieved by using half-bridge submodules instead of full-power MMC stations. However, due to the feeder integration, the eM-FACI’s unique configuration makes the parameter design more complicated than the conventional BTB-MMC. This paper proposes a parameter design scheme for the eM-FACI’s according to the extreme fluctuate power interaction condition. And the extreme case is designed by the current decoupling and the power decoupling between different feeders. The feasibility and effectiveness of the proposed method are verified by MATLAB/Simulink.

Modeling and Evaluation of Inertia Emulation Control for DFIG Wind Turbine

Haoshu SHAO,Xu CAI,Jianwen Zhang,Yunfeng Cao,Fangquan RAO,Dapeng ZHENG,Dangsheng ZHOU,Yan WANG 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

With the increasing penetration of renewable energy generators in power grid, many inertia emulation control strategies have been raised to solve the problem of reduced power system inertia. A co-simulation research platform is built based on RTDS and GH Bladed, detailed comparisons are made in terms of inertia response performance, weak grid operation stability, secondary frequency drop and wind tower load analysis. Research results point out that different control schemes are similar in inertia response while virtual synchronous generator control (VSG) and inertial synchronization control (ISynC) can improve weak grid operation stability, VSG strategy is also effective in reducing frequency secondary drop and wind tower fatigue load, the combination of VSG and ISynC can get the best control results.