Flow ripple analysis and structural parametric design of a piston pump

Xiaofeng Wu,Chihkeng Chen,Chihwei Hong,Yafeng He 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.9

The ripple in the outlet flow from a high-pressure piston pump is caused by pressure pulses in the piston cavity when it rotates through the transition region of the valve plate. We propose a parametric design that optimizes the transition region structure of a piston pump valve plate to reduce the ripple in the outlet flow. For a high- pressure piston pump, a theoretical model of the piston cavity is developed that includes fluid compression properties and leakages. The piston pump parametric model is built using AMESIM software and a simulation is conducted. The results show that the ripple in the outlet flow is affected by the outlet pressure and the pump’s speed and by the structure of the pre-compression region of the valve plate. To minimize the ripple in the outlet flow from the piston pump, the structural parameters in the pre-compression region are optimized as the design variables using the software, ISIGHT, which integrates the piston pump parametric model in AMESIM. After optimization, the ripple in the outlet flow rate is, respectively, reduced by 37.05 %, 38.54 % and 41.04 % for outlet pressures of 200 bar, 300 bar and 400 bar. Finally, a flow ripple test experiment is performed to verify the simulation results.

Achieving fixed-time synchronization of the Kuramoto model via improving control techniques

Wu Jie,Liu Mingqi,Wang Xiaofeng,Ma Ru-ru 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.79 No.11

This paper further analyzes the fixed-time (FxT) phase agreement (PA) and the frequency synchronization (FS) of the Kuramoto model with identical and non-identical oscillators, respectively. The non-chattering control protocol is carefully picked to overcome the deficiency of the signum function contained in the conventional finite-time (FT)/FxT controllers, which improves the synchronized performance of networked systems. Furthermore, for reducing control cost, the switching control scheme is taken into consideration. Through the utilization of FxT stability theory, several sufficient conditions are derived successively for achieving the FxT PA and FS, in which the upper bound time estimates for arriving at PA and FS are given regardless of the initial states of the Kuramoto model. Finally, some simulation results lead to the conclusion that the proposed theoretical analysis is correct and effective.

RESIDENTS’ PERCEPTIONS AND ATTITUDES OF NIMBY FACILITIES

XIAOFENG LIU,XIAOLING WU,ZHANG CHENG 한국무역학회 2017 한국무역학회 국제학술대회 Vol.2017 No.11

New receipt-free voting scheme using double-trapdoor commitment

Chen, Xiaofeng,Wu, Qianhong,Zhang, Fangguo,Tian, Haibo,Wei, Baodian,Lee, Byoungcheon,Lee, Hyunrok,Kim, Kwangjo Elsevier 2011 Information sciences Vol.181 No.8

<P><B>Abstract</B></P><P>It is considered to be the most suitable solution for large scale elections to design an electronic voting scheme using blind signatures and anonymous channels. Based on this framework, Okamoto first proposed a receipt-free voting scheme <ce:cross-ref refid='b0150'>[30]</ce:cross-ref> for large scale elections. However, in the following paper, Okamoto <ce:cross-ref refid='b0155'>[31]</ce:cross-ref> proved that the scheme <ce:cross-ref refid='b0150'>[30]</ce:cross-ref> was not receipt-free and presented two improved schemes. One scheme requires the help of the parameter registration committee and the other needs a stronger physical assumption of the voting booth. In this paper, we utilize the double-trapdoor commitment to propose a new receipt-free voting scheme based on blind signatures for large scale elections. Neither the parameter registration committee nor the voting booth is required in our scheme. We also present a more efficient zero-knowledge proof for secret permutation. Therefore, our scheme is much more efficient than Okamoto’s schemes <ce:cross-refs refid='b0150 b0155'>[30,31]</ce:cross-refs> with the weaker physical assumptions. Moreover, we prove that our scheme can achieve the desired security properties.</P>

Stochastic fixed-time synchronization of chaotic systems via smooth control

Jie Wu,Xiaofeng Wang,Ru-ru Ma 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.9

This paper is concerned with the fixed-time synchronization of two chaotic systems, and further takes the stochastic noise into consideration. A novel smooth control protocol is developed to overcome the chattering problem caused by the signum function contained in the conventional finite/fixed-time controllers. In the light of the (stochastic) fixedtime stability theory, the sufficient conditions are derived for achieving the (stochastic) fixedtime synchronization of two chaotic systems, in which the upper bound of synchronization time can be estimated in advance. Finally, two classical chaotic systems are used to verify the validity of proposed theoretical results, which shows that fixed-time synchronization of chaotic systems is robust to noise perturbation.

Electrochemical Determination of Artemisinin Using a Multi-wall Carbon Nanotube Film-modified Electrode

Yang, Xiaofeng,Gan, Tian,Zheng, Xiaojiang,Zhu, Dazhai,Wu, Kangbing Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.7

Artemisinin, the effective ingredient of Chinese herb Artemisia annua L (Qinghao in Chinese), has been proved to be effective to antimalarial. Herein, a reliable, sensitive and convenient electrochemical method was developed for the determination of artemisinin utilizing the excellent properties of multi-wall carbon nanotube (MWNT). The electrochemical behavior of artemisinin was investigated. It is found that the reduction peak current of artemisinin remarkably increases and the peak potential shifts positively by 240 mV at the MWNT film-modified electrode. These phenomena indicate that the MWNT film exhibits efficient catalytic activity to the electrochemical reduction of artemisinin. The effects of pH value, amount of MWNT, scan rate and accumulation time were examined. The limit of detection (S/N = 3) is as low as 10 $\mu$ g $L^{-1}$. Finally, this newly developed method was used to determine the content of artemisinin in Artemisia annua L.

Current Status and Future Trends of Cold Atmospheric Plasma as an Oncotherapy

Dai Xiaofeng,Wu Jiale,Lu Lianghui,Chen Yuyu 한국응용약물학회 2023 Biomolecules & Therapeutics(구 응용약물학회지) Vol.31 No.5

Cold atmospheric plasma (CAP), a redox modulation tool, is capable of inhibiting a wide spectrum of cancers and has thus been proposed as an emerging onco-therapy. However, with incremental successes consecutively reported on the anticancer efficacy of CAP, no consensus has been made on the types of tumours sensitive to CAP due to the different intrinsic characteristics of the cells and the heterogeneous design of CAP devices and their parameter configurations. These factors have substantially hindered the clinical use of CAP as an oncotherapy. It is thus imperative to clarify the tumour types responsive to CAP, the experimental models available for CAP-associated investigations, CAP administration strategies and the mechanisms by which CAP exerts its anticancer effects with the aim of identifying important yet less studied areas to accelerate the process of translating CAP into clinical use and fostering the field of plasma oncology.

Preparation and Properties Characterization of Interpenetrating Polymer Networks/Organically Modified Montmorillonite/Scrap Leather Fibers Composites

Xinfeng Wu,Zehui Duan,Ying Wang,Yuan Gao,Kai Sun,Runhua Fan,Xiaofeng Li 한국섬유공학회 2019 Fibers and polymers Vol.20 No.9

An interpenetrating polymer networks (IPNs) based on the anhydride-cured cycloaliphatic epoxy and the trifunctionalacrylate resin cross-linked by peroxide was modified by incorporation of organic montmorillonites (OMMTs) andscrap leather fibers (SLFs). OMMTs and SLFs were introduced into IPNs via a violently mechanical stirring technique whichprovided a very well-dispersed phase of OMMTs and SLFs in matrix. Non-isothermal curing behaviors of IPNs/OMMTs/SLFs composites were investigated by means of the differential scanning calorimeter (DSC). The results of DSC testsshowed that the introduction of OMMTs and SLFs into IPNs accelerated the curing reaction of epoxy systems. In comparisonwith the case of the pristine IPNs, the thermal stability properties, the glass transition temperature, mechanical properties ofIPNs/OMMTs/SLFs composites were markedly enhanced. A desirable toughening-strengthening balance of the compositeshad been obtained at 5 pbw(parts by weight) of OMMTs and 0.5 pbw of SLFs. Significant improvements in performances ofIPNs/OMMTs/SLFs composites obtained through the addition of OMMTs and SLFs in IPNs matrix were associated withtheir good co-reinforcement and co-dispersion effects. The macroscopic properties of the composites were found to bestrongly dependent on their concentrations, components, dispersion, and the resulted morphological structures.

Electrochemical Determination of Artemisinin Using a Multi-wall Carbon Nanotube Film-modified Electrode

Kangbing Wu,Xiaofeng Yang,Tian Gan,Xiaojiang Zheng,Dazhai Zhu 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.7

Artemisinin, the effective ingredient of Chinese herb Artemisia annua L (Qinghao in Chinese), has been proved to be effective to antimalarial. Herein, a reliable, sensitive and convenient electrochemical method was developed for the determination of artemisinin utilizing the excellent properties of multi-wall carbon nanotube (MWNT). The electrochemical behavior of artemisinin was investigated. It is found that the reduction peak current of artemisinin remarkably increases and the peak potential shifts positively by 240 mV at the MWNT film-modified electrode. These phenomena indicate that the MWNT film exhibits efficient catalytic activity to the electrochemical reduction of artemisinin. The effects of pH value, amount of MWNT, scan rate and accumulation time were examined. The limit of detection (S/N = 3) is as low as 10 μ g L−1. Finally, this newly developed method was used to determine the content of artemisinin in Artemisia annua L.

A Study on the Impact of Multiple Failures on OSPF Convergence

Dan Zhao,Xiaofeng Hu,Chunqing Wu 보안공학연구지원센터 2013 International Journal of Hybrid Information Techno Vol.6 No.3