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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 ).
Yupeng Cao,Jianwen Ding,Rui Zhang,Guizhong Xu 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.9
Vertical flow has an important effect on consolidation rate of ultra-soft soil, but the influence law and influence level on the degree of large-strain consolidation have not been quantitatively evaluated. Based on the negative axisymmetric large strain consolidation (NALSC) model, the variation laws of calculation error of consolidation degree ignoring vertical flow with consolidation time and strain are studied under different values of H/re (ratio of soil thickness to influence radius), w0/wL (ratio of initial water content to liquid limit) and kh/kv (ratio of horizontal permeability coefficient to vertical permeability coefficient). Taking 10% as the error threshold, the H/re values ignoring vertical flow are given, and the difference between them in the theories of large-strain and small-strain is discussed. The results show that the effect of vertical flow on degree of stress consolidation (Up) is greater than degree of strain consolidation (Us). The H/re values neglecting the effect of vertical flow on the degree of consolidation in large-strain theory are less than those in small-strain theory. The calculation errors affected by vertical flow decrease with the increase of H/re and kh/kv. Error of Us affected by vertical flowdecreases, whereas error of Up increases with the increase of w0/wL. The effect of vertical flow on the degree of consolidation is greater when well resistance is considered.
Zhao, Hongying,Zhang, Jun,Shao, Haiyu,Liu, Jianwen,Jin, Mengran,Chen, Jinping,Huang, Yazeng Korean Society for Molecular and Cellular Biology 2017 Molecules and cells Vol.40 No.3
Transforming growth factor ${\beta}1$ $(TGF{\beta}1)/Smad4$ signaling plays a pivotal role in maintenance of the dynamic balance between bone formation and resorption. The microRNA miR-155 has been reported to exert a significant role in the differentiation of macrophage and dendritic cells. The goal of this study was to determine whether miR-155 regulates osteoclast differentiation through $TGF{\beta}1/Smad4$ signaling. Here, we present that $TGF{\beta}1$ elevated miR-155 levels during osteoclast differentiation through the stimulation of M-CSF and RANKL. Additionally, we found that silencing Smad4 attenuated the upregulation of miR-155 induced by $TGF{\beta}1$. The results of luciferase reporter experiments and ChIP assays demonstrated that $TGF{\beta}1$ promoted the binding of Smad4 to the miR-155 promoter at a site located in 454 bp from the transcription start site in vivo, further verifying that miR-155 is a transcriptional target of the $TGF{\beta}1/Smad4$ pathway. Subsequently, TRAP staining and qRT-PCR analysis revealed that silencing Smad4 impaired the $TGF{\beta}1$-mediated inhibition on osteoclast differentiation. Finally, we found that miR-155 may target SOCS1 and MITF to suppress osteoclast differentiation. Taken together, we provide the first evidence that $TGF{\beta}1/Smad4$ signaling affects osteoclast differentiation by regulation of miR-155 expression and the use of miR-155 as a potential therapeutic target for osteoclast-related diseases shows great promise.
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.
Hongying Zhao,Jun Zhang,Haiyu Shao,Jianwen Liu,Mengran Jin,Jinping Chen,Yazeng Huang 한국분자세포생물학회 2017 Molecules and cells Vol.40 No.3
Transforming growth factor 1 (TGF1)/Smad4 signaling plays a pivotal role in maintenance of the dynamic balance between bone formation and resorption. The microRNA miR-155 has been reported to exert a significant role in the differ-entiation of macrophage and dendritic cells. The goal of this study was to determine whether miR-155 regulates osteoclast differentiation through TGF1/Smad4 signaling. Here, we present that TGF1 elevated miR-155 levels during osteoclast differentiation through the stimulation of M-CSF and RANKL. Additionally, we found that silencing Smad4 attenuated the upregulation of miR-155 induced by TGF1. The results of luciferase reporter experiments and ChIP assays demonstrated that TGF1 promoted the binding of Smad4 to the miR-155 promoter at a site located in 454 bp from the transcription start site in vivo, further verifying that miR-155 is a transcriptional target of the TGF1/Smad4 pathway. Subsequently, TRAP staining and qRT-PCR analysis revealed that silencing Smad4 impaired the TGF1-mediated inhibition on osteoclast differentiation. Finally, we found that miR-155 may target SOCS1 and MITF to suppress osteoclast differentiation. Taken together, we provide the first evidence that TGF1/Smad4 signaling affects osteoclast differentiation by regulation of miR-155 expression and the use of miR-155 as a potential therapeutic target for osteoclast-related diseases shows great promise.
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.
Yupeng Cao,Jing Zhang,Jianwen Xu,Guizhong Xu 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.12
A calculation model has been developed for large-strain radial consolidation incorporating lateral deformation in order to solve the problem of poor consolidation prediction for dredged sludge at high water content in vacuum preloading process. The differential solution for the proposed model is given, considering the effect of initial water content on the compression behavior. The model is suitable for unconsolidated soil and normally consolidated soil, which can take into account such factors as lateral deformation, varying compressibility and permeability coefficients, smearing effect, self-weight stress, negative pressure attenuation along the depth, etc. The proposed model is verified by comparing it with other existing theoretical solutions. Poisson's ratio (v) is used to reflect the influence of lateral deformation on soil consolidation. The results show that lateral deformation has an important influence on soil consolidation degree, especially on consolidation degree defined by stress (Up). The consolidation rate increases with the increase of v. The traditional equal-strain solution overestimates the consolidation rate of foundation. At the same normalized elevation, the void ratio increases while the excess pore water pressure decreases with the increase of v.
Jing Lyu,Jinshui Dai,Chen Zhang,Jianwen Zhang,Xu Cai 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
This paper presents a comparative analysis of impedance characteristics of modular multilevel converter (MMC) with direct modulation and compensated modulation. The analytical derivations of the ac-side impedances of the MMC with these two modulation modes are provided, respectively, which are then validated by the measured impedances in the time-domain simulation model. Subsequently, a case study is carried out to show the impact of the two modulation modes on the stability of the MMCbased interconnected system using the impedance-based analysis method. The findings could provide a reference for controller design of MMC-based power electronic systems from a stability perspective.