Deformation of the PDMS Membrane for a Liquid Lens Under Hydraulic Pressure

Haipeng Gu,Zihao Gan,Huajie Hong,Keyan He 한국광학회 2021 Current Optics and Photonics Vol.5 No.4

In the present study, a hyperelastic constitutive model is built by complying with a simplified hyperelastic strain energy function, which yields the numerical solution for a deformed polydimethylsiloxane (PDMS) membrane in the case of axisymmetric hydraulic pressure. Moreover, a nonlinear equilibrium model is deduced to accurately express the deformation of the membrane, laying a basis for precise analysis of the optical transfer function. Comparison to experimental and simulated data suggests that the model is capable of accurately characterizing the deformation behavior of the membrane. Furthermore, the stretch ratio derived from the model applies to the geometrical optimization of the deformed membrane.

Optimal Energy Management Strategy for an Islanded Microgrid with Hybrid Energy Storage

Chen Haipeng,Gao Lin,Zhang Zhong,Li He 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.3

Due to the randomness and volatility of light intensity and wind speed, renewable generation and load management are facing new challenges. This paper proposes a novel energy management strategy to extend the life cycle of the hybrid energy storage system (HESS) based on the state of charge (SOC) and reduce the total operating cost of the islanded microgrid (MG). In this paper, a demand response (DR) optimization model of independent MG is introduced considering the total cost of MG operation, carbon emission and new energy consumption penalty. Meanwhile, by analyzing the SOC of the HESS, starting and stopping criteria (SSC) of diesel generator (DG), residential load classifi cation, an optimal energy management strategy for island grid operation of HESS based on DR is proposed. Then, the particle swarm optimization (PSO) algorithm with improved acceleration factor is applied to solve the optimization scheme. The simulation results show that a novel energy management strategy has improved the economical and reliable performance of the independent MG via setting the charging and discharging criteria of HESS and SSC of DG. Moreover, fl exible scheduling of part controllable loads can be used to improve the renewable energy consumption rate and reduce the loss of load rate.

Surface Coating of Polytetrafluoroethylene with Extracellular Matrix and Anti-CD34 Antibodies Facilitates Endothelialization and Inhibits Platelet Adhesion Under Sheer Stress

Lei Chen,Haipeng He,Mian Wang,Xiaoxi Li,Henghui Yin 한국조직공학과 재생의학회 2017 조직공학과 재생의학 Vol.14 No.4

Expanded polytetrafluoroethylene (ePTFE) polymers do not support endothelialization because of nonconductive characteristics towards cellular attachment. Inner surface modification of the grafts can improve endothelialization and increase the long-term patency rate of the ePTFE vascular grafts. Here we reported a method of inner-surface modification of ePTFE vascular graft with extracellular matrix (ECM) and CD34 monoclonal antibodies (CD34 mAb) to stimulate the adhesion and proliferation of circulating endothelial progenitor cells on ePTFE graft to enhance graft endothelialization. The inner surface of ECM-coated ePTFE grafts were linked with CD34 mAb in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide (EDC/NHS) solution and the physicochemical properties, surface morphology, biocompatibility, and hemocompatibility of the grafts were studied. The hydrophilicity of CD34 mAb-coated graft inner surface was significantly improved. Fourier transform infrared spectroscopy analysis confirmed ECM and CD34 mAb cross-linking in the ePTFE vascular grafts with our method. Scanning electron microscopy analysis showed protein layer covering uniformly on the inner surface of the modified grafts. The cell-counting kit-8 (CCK-8) assay confirmed that the modified graft has no obvious cytotoxicity. The modified graft showed a low hemolytic rate (0.9%) in the direct contact hemolysis test, suggesting the modification improved hemocompatibility of biopolymers. The modification also decreased adhesion of platelets, while significantly increased the adhesion of endothelial cells on the grafts. We conclude that our method enables ePTFE polymers modification with ECM and CD34 mAb, facilitates endothelialization, and inhibits platelet adhesion on the grafts, thus may increase the long-term patency rate of the prosthetic bypass grafts.

Rigid-flexible hybrid modeling and dynamic simulation of three-coordinate heavy-load transfer vehicle

Junxia Jiang,Haipeng Liao,Yuxiao He,Xinyuan Zhang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.1

The spent fuel in the nuclear radiation environment is generally transported by transfer vehicles, which are required to be able to run smoothly under high speed and high acceleration. In this paper, dynamic analysis and simulation of a new type of heavy-load transfer vehicle were carried out. Firstly, the design structure of the transfer vehicle was presented, and the theoretical calculation methods for the forces on the V-shaped rollers and the dynamic deflection of the column were proposed. Then the working space of the vehicle was analyzed. And the dynamic model of rigid bodies and flexible bodies were established according to the Lagrange equations. Moreover, the velocity and acceleration of main components and the contact forces of the V-shaped rollers were analyzed by using ADAMS, and the optimal control strategy was proposed. Finally, the motors output torque of the vehicle was tested to validate the accuracy of the theoretical analysis and simulation. The experimental results are in good agreement with the theoretical and simulation results, and the dynamic performance of the transfer vehicle meets the design requirements.

Design of 39-GHz Up- and Down-Conversion Mixers for 5G mmWave TDD Applications

Wang Yi-Yang,Duan Haipeng,He Long,Wu Xu,Wang Dongming,Li Lianming 한국전자파학회 2023 Journal of Electromagnetic Engineering and Science Vol.23 No.2

This article presents fully integrated 39-GHz bidirectional up- and down-conversion mixers for 5G millimeter-wave (mmWave) applications. Fabricated in a 65-nm CMOS process with a 1.2-V supply voltage, the up- and down-conversion mixers consume 39 and 43 mW, respectively. For 5G time-division duplexing (TDD) operation, intermediate-frequency (IF)/local-oscillator (LO)/radio-frequency (RF) T/R switches are introduced. For better isolation and low insertion loss between the up- and down-conversion mixer, a series-shunt singlepole double-throw (SPDT) structure and an equivalent lumped λ/4 transmission line are proposed for IF and RF T/R switches, respectively. To realize compact area and wide bandwidth, a transformer-based matching network is adopted in this design. Targeting multi-channel phased array applications, the measurement result shows that the up-conversion mixer achieves a 2.5-dB peak conversion gain with 6.5 GHz 3-dB bandwidth. Including the insertion loss of the switch and IF signal routing, at the maximum gain of 36.5 GHz, the up-conversion mixer achieves an output 1-dB gain compression point (OP1dB) of 2.5 dBm. Furthermore, the down-conversion mixer achieves a 5-dB peak conversion gain with a 9.7-GHz 3-dB bandwidth.

Elucidating Bottlenecks to the Efficient Preparation of AB₅-Hexamer Mucosal Adjuvant Protein LTm by Genetic Engineering

( Di Liu ),( Fabiao Hu ),( Wenpeng Wang ),( Dong Wu ),( Xiujuan He ),( Wenyun Zheng ),( Haipeng Liu ),( Xingyuan Ma ) 한국미생물생명공학회(구 한국산업미생물학회) 2017 Journal of microbiology and biotechnology Vol.27 No.8

Escherichia coli heat-labile enterotoxin (LT) and its non-toxic mutant (LTm) are well-known powerful mucosal adjuvants and immunogens. However, the yields of these adjuvants from genetically engineered strains remain at extremely low levels, thereby hindering their extensive application in fundamental and clinical research. Therefore, efficient production of these adjuvant proteins from genetically engineered microbes is a huge challenge in the field of molecular biology. In order to explore the expression bottlenecks of LTm in E. coli, we constructed a series of recombinant plasmids based on various considerations and gene expression strategies. After comparing the protein expression among strains containing different recombinant plasmids, the signal sequence was found to be critical for the expression of LTm and its subunits. When the signal sequence was present, the strong hydrophobicity and instability of this amino acid sequence greatly restricted the generation of subunits. However, when the signal sequence was removed, abundantly expressed subunits formed inactive inclusion bodies that could not be assembled into the hexameric native form, although the inclusion body subunits could be refolded and the biological activity recovered in vitro. Therefore, the dilemma choice of signal sequence formed bottlenecks in the expression of LTm. These results reveal the expression bottlenecks of LTm, provide guidance for the preparation of LTm and its subunits, and certainly help to promote efficient preparation of this mucosal adjuvant protein.