Full-scale test of dampers for stay cable vibration mitigation and improvement measures

Zhou, Haijun,Xiang, Ning,Huang, Xigui,Sun, Limin,Xing, Feng,Zhou, Rui Techno-Press 2018 Structural monitoring and maintenance Vol.5 No.4

This paper reported test of full-scale cables attached with four types of dampers: viscous damper, passive Magneto-Rheological (MR) damper, friction damper and High Damping Rubber (HDR) damper. The logarithmic decrements of the cable with attached dampers were calculated from free vibration time history. The efficiency ratios of the mean damping ratios of the tested four dampers to theoretical maximum damping ratio were derived, which was very important for practical damper design and parameter optimization. Non-ideal factors affecting damper performance were discussed based on the test results. The effects of concentrated mass and negative stiffness were discussed in detail and compared theoretically. Approximate formulations were derived and verified using numerical solutions. The critical values for non-dimensional concentrated mass coefficient and negative stiffness were identified. Efficiency ratios were approximately 0.6, 0.6, and 0.3 for the viscous damper, passive MR damper and HDR damper, respectively. The efficiency ratio for the friction damper was between 0-1.0. The effects of concentrated mass and negative stiffness on cable damping were positive as both could increase damping ratio; the concentrated mass was more effective than negative stiffness for higher vibration modes.

Leader-following Cluster Consensus in Multi-agent Systems with Intermittence

Da Huang,Haijun Jiang,Zhiyong Yu,Chengjun Kang,Cheng Hu 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.2

In this paper, the cluster consensus problem of first-order nonlinear multi-agent systems with aperiodic intermittent communication is studied through pinning leader-following approach. The pinning consensus algorithm based on the relative local intermittent information is designed according to the varies linking ways of clustered network structure. New notions of leading intermittence and inter-cluster intermittence which related to the intermittent linking ways of leader-following clustered structure are developed, and several new systems with intermittence are established due to the new notions. Besides, dynamics with inherent delay are also considered to extend our results to a more general framework. The original communication graph without intermittent pattern is supposed to be directed and weakly connected. Some consensus criteria are derived to guarantee that the cluster consensus problem for the systems with intermittent communication can be solved. Finally, numerical simulations are given to illustrate the effectiveness of the theoretical results.

Optimal Dispatch for a Combined Cooling, Heating and Power Microgrid Considering Building Virtual Energy Storage

Lijun Yang,Haijun Guo,Kaiting Huang 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.2

Because buildings have certain heat capacity, when the thermal power changes, the indoor temperature has a relative lag of change, while the feeling to comfortable temperature of the human body lies within a certain range. Based on the energy storage characteristics of buildings, this paper structures the optimal dispatch model of a combined cooling, heating, and power system (CCHP) and the virtual energy storage system (VESS) is integrated into the model of optimizing schedule on microgrid. This will achieve the charge and discharge management of microgrid virtual energy storage system, with the optimization objectives of minimizing the economic, environmental and energy indexes through determining the weight coeffi cient of each index by analytic hierarchy process (AHP) and through the adjustment of the indoor temperature of the building within the range of human comfort. Finally, taking the summer refrigeration scenario as an example and comparing two microgrids of two types of buildings with or without virtual energy storage, this paper concludes that compared with traditional optimization dispatching methods, the combined cooling, heating, and power optimization dispatching method adopting virtual energy storage fully excavates the potential of the buildings’ virtual storage and every aspect has been improved in terms of economy, environment and energy.

Discrete Element Simulation of Macro and Micro Mechanical Properties of Round Gravel Material under Triaxial Stress

Shaokun Ma,Haijun Huang,Fapai Tian,Jian Gong,Jiabing Zhang,Zhibo Duan 대한토목학회 2024 KSCE Journal of Civil Engineering Vol.28 No.5

In this study, the effects of relative density and confining pressure on the shear characteristics of round gravel are investigated using a large-scale triaxial apparatus and the discrete element method. A simple and efficient numerical method for simulating flexible membranes is introduced. The results show that the stress-strain curves develop from hardened to softened type with increasing relative density, while the stress-strain curves develop from softened to hardened type with increasing confining pressure. As the axial strain increases, the strong contact force chains are vertically distributed, and the larger the relative density and confining pressure, the greater the number and thickness of the strong contact force chains. In the shear process, the distribution of average normal and tangential contact forces show “peanut-shaped” and “petal-shaped”, respectively. The increase in relative density increases the anisotropy of the specimen, while the increase in confining pressure results in a decrease. A linear relationship exists between the macroscopic stress ratio and the anisotropy coefficient. The anisotropy coefficient of the normal contact force provides the greatest contribution to the macroscopic shear strength (about 55%), followed by the anisotropy coefficient of the contact normal (about 26%) and that of the tangential contact force (about 19%).

BER Analysis of Coherent Free Space Optical Communication Systems with Holographic Modal Wavefront Sensor

Liu, Wei,Yao, Kainan,Huang, Danian,Cao, Jingtai,Wang, Liang,Gu, Haijun Optical Society of Korea 2017 Current Optics and Photonics Vol.1 No.1

Degradation of bit-error-rate (BER), caused by atmospheric turbulence, seriously hinders the performance of coherent Free Space Optical (FSO) communication systems. An adaptive optics system proves to be effective in suppressing the atmospheric turbulence. The holographic modal wavefront sensor (HMWFS) proposed in our previous work, noted for its fast detecting rates and insensitivity to beam scintillation, is applied to the coherent FSO communication systems. In this paper, based on our previous work, we first introduce the principle of the HMWFS in brief and give the BER of the coherent FSO with homodyne detection in theory, and then analyze the improvement of BER for a coherent FSO system based on our previous simulation works. The results show that the wavefront sensor we propose is better for weak atmospheric turbulence. The most obvious advantages of HMWFS are fast detecting rates and insensitivity to beam scintillation.

Synthesis of a Chemically Organic/Inorganic Hybrid Adsorbent and Its Adsorption to Phenol in Aqueous Solution

Man Yang,Yun Huang,Haijun Cao,Yuanhua Lin,Amin Song,Qingyuan Sun 한국고분자학회 2017 폴리머 Vol.41 No.3

A novel organic/inorganic hybrid TVE-resin containing SiO₂ structure for phenol removal is successfully prepared by dispersion polymerization, in which the inorganic phase is composed of nano-SiO₂ modified by vinyltrimethoxy silane (VTMS) and the organic phase is constituted of ethylene glycol dimethacrylate (EGDMA). The chemical structure and physical properties of TVE-resin are characterized by FTIR, TGA, SEM and BET. The adsorption studies imply that the novel materials show optimum adsorption capacity at pH=6, dose 0.1 g, contact time 60 min, initial concentration 3000 mg/L and room temperature. The pseudo first-order model can be well fitted with the kinetic process. According to the adsorption isotherm analysis, the Freundlich model gives a better fit to the experimental data, indicating a multiple molecular adsorption for phenol removal. The calculated thermodynamic parameters indicate an exothermic and spontaneous process. A mixture desorption solvent containing methanol and deionized water (v:v, 1:1) can regenerate the TVE-resin completely and the resin displays good reusability after five regeneration recycles.

BER Analysis of Coherent Free Space Optical Communication Systems with Holographic Modal Wavefront Sensor

Wei Liu,Kainan Yao,Danian Huang,Jingtai Cao,Liang Wang,Haijun Gu 한국광학회 2017 Current Optics and Photonics Vol.1 No.1

Degradation of bit-error-rate (BER), caused by atmospheric turbulence, seriously hinders the performanceof coherent Free Space Optical (FSO) communication systems. An adaptive optics system proves to beeffective in suppressing the atmospheric turbulence. The holographic modal wavefront sensor (HMWFS)proposed in our previous work, noted for its fast detecting rates and insensitivity to beam scintillation,is applied to the coherent FSO communication systems. In this paper, based on our previous work, wefirst introduce the principle of the HMWFS in brief and give the BER of the coherent FSO with homodynedetection in theory, and then analyze the improvement of BER for a coherent FSO system based on ourprevious simulation works. The results show that the wavefront sensor we propose is better for weakatmospheric turbulence. The most obvious advantages of HMWFS are fast detecting rates and insensitivityto beam scintillation.

Phosphatidylcholine regulates NF-κB activation in attenuation of LPS-induced inflammation: evidence from in vitro study

Cheng, Meijuan,Pan, Hongying,Dai, Yining,Zhang, Jiajie,Tong, Yongxi,Huang, Yicheng,Wang, Mingshan,Huang, Haijun 한국통합생물학회 2018 Animal cells and systems Vol.22 No.1

Phosphatidylcholine (PC) has been demonstrated as anti-inflammatory and antioxidant/pro-oxidant molecules. In this study, we investigated the protective effects of PC on inflammatory bowel disease (IBD) caused by lipopolysaccharide (LPS)-induced injury in intestinal epithelia cells. The IEC-6 cells (intestinal epithelia cells) were stimulated with LPS ($1{\mu}g/mL$) for 24 h with or without PC pretreatment, in the next steps: (1) the level of the inflammatory cytokine tumor necrosis factor (TNF)-${\alpha}$ was measured with ELISA; (2) the nuclear translocation and phosphorylation of NF-${\kappa}B$ was investigated with Western blot, EMSA, immunofluorence assay; (3) the protein phosporylation levels in MAPK signaling pathway were detected with Western blot method. The results showed: (1) compared with the normal group, 10 and $20{\mu}g/mL$ of PC significantly inhibited the production and activation of TNF-${\alpha}$, (P < 0.01); (2) pretreatment with PC inhibited LPS-induced nuclear translocation and phosphorylation of p65 in IEC-6 cells; (3) pretreatment with PC inhibited the protein phosphorylation levels in MAPK signaling pathway. Our findings indicated that PC had the effect to protect IEC-6 cells from LPS-induced injury and this effect was exerted possibly through inhibiting the TNF-${\alpha}$ secretion, down-regulating nuclear translocation and phosphorylation of p65 and inhibiting MAPK signaling pathways.

Phosphatidylcholine regulates NF-κB activation in attenuation of LPS-induced inflammation: evidence from in vitro study

Meijuan Cheng,Hongying Pan,Yining Dai,Jiajie Zhang,Yongxi Tong,Yicheng Huang,Mingshan Wang,Haijun Huang 한국통합생물학회 2018 Animal cells and systems Vol.22 No.1

Phosphatidylcholine (PC) has been demonstrated as anti-inflammatory and antioxidant/pro-oxidant molecules. In this study, we investigated the protective effects of PC on inflammatory bowel disease (IBD) caused by lipopolysaccharide (LPS)-induced injury in intestinal epithelia cells. The IEC-6 cells (intestinal epithelia cells) were stimulated with LPS (1 μg/mL) for 24 h with or without PC pretreatment, in the next steps: (1) the level of the inflammatory cytokine tumor necrosis factor (TNF)-α was measured with ELISA; (2) the nuclear translocation and phosphorylation of NF-κB was investigated with Western blot, EMSA, immunofluorence assay; (3) the protein phosporylation levels in MAPK signaling pathway were detected with Western blot method. The results showed: (1) compared with the normal group, 10 and 20 μg/mL of PC significantly inhibited the production and activation of TNF-α, (P < 0.01); (2) pretreatment with PC inhibited LPS-induced nuclear translocation and phosphorylation of p65 in IEC-6 cells; (3) pretreatment with PC inhibited the protein phosphorylation levels in MAPK signaling pathway. Our findings indicated that PC had the effect to protect IEC-6 cells from LPS-induced injury and this effect was exerted possibly through inhibiting the TNF-ɑ secretion, down-regulating nuclear translocation and phosphorylation of p65 and inhibiting MAPK signaling pathways.

Smart and versatile biomaterials for cutaneous wound healing

Minxiong Li,Wenzheng Xia,Yi Min Khoong,Lujia Huang,Xin Huang,Hsin Liang,Yun Zhao,Jiayi Mao,Haijun Yu,Tao Zan 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

The global increase of cutaneous wounds imposes huge health and financial burdens on patients and society. Despite improved wound healing outcomes, conventional wound dressings are far from ideal, owing to the complex healing process. Smart wound dressings, which are sensitive to or interact with changes in wound condition or environment, have been proposed as appealing therapeutic platforms to effectively facilitate wound healing. In this review, the wound healing processes and features of existing biomaterials are firstly introduced, followed by summarizing the mechanisms of smart responsive materials. Afterwards, recent advances and designs in smart and versatile materials of extensive applications for cutaneous wound healing were submarined. Finally, clinical progresses, challenges and future perspectives of the smart wound dressing are discussed. Overall, by mapping the composition and intrinsic structure of smart responsive materials to their individual needs of cutaneous wounds, with particular attention to the responsive mechanisms, this review is promising to advance further progress in designing smart responsive materials for wounds and drive clinical translation.