Stabilization of a Scalar Continuous Time Linear System with Unknown Noise Based on Two-stage Event-triggering

Chenyi Wang,Qiang Ling 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.5

This paper aims to ensure the input-to-state stability (ISS) of a continuous-time linear scalar system which suffers from quantization, unknown noise, and network delay. To deal with the unknown noise, we design a dynamic quantization scheme that switches between “zooming-in” and “zooming-out”, and adjusts a “zooming” parameter of finite-level quantizers. Moreover, a two-stage event-triggering scheme is proposed to determine whether to sample the state and whether to transmit the encoded state information. The joint design of the dynamic quantization scheme and the two-stage event-triggering scheme can well counteract the effects of unknown noise and network delay on the desired ISS of the concerned system. Moreover, the proposed schemes can avoid Zeno behavior and do not require any prior bounds on the unknown noise. The effectiveness of the proposed schemes is further verified through simulations.

A clustered sulfonated poly(ether sulfone) based on a new fluorene-based bisphenol monomer

Wang, Chenyi,Shin, Dong Won,Lee, So Young,Kang, Na Rae,Robertson, Gilles P.,Lee, Young Moo,Guiver, Michael D. The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.48

<P>A new fluorene-based bisphenol monomer containing two pendant phenyl groups, 9,9-bis(3-phenyl-4-hydroxy)phenyl-fluorene, was readily synthesized in high yield by a one-step reaction from inexpensive starting materials. A series of poly(ether sulfone)s with clustered sulfonic acid groups was prepared for fuel cell applications by polycondensation of the new monomer with bis(4-hydroxyphenyl)sulfone and bis(4-fluorophenyl)sulfone, followed by sulfonation exclusively on the fluorene rings and pendant phenyl rings, using concentrated sulfuric acid at room temperature. The sulfonated polymers gave tough, flexible, and transparent membranes by solvent casting. The ionic exchange capacity (IEC), water-uptake, dimensional stabilities, mechanical properties, thermal and oxidative stabilities as well as proton conductivities and single fuel cell properties of the membranes were investigated. The membranes with high IEC values show high proton transport properties, and their proton conductivities exhibit lower dependence on relative humidity compared with typical aromatic ion exchange membranes. 4-SPES-38 with an IEC value of 2.23 mequiv. g<SUP>−1</SUP> displays comparable fuel cell performance with Nafion 212 under low humidity conditions.</P> <P>Graphic Abstract</P><P>A new fluorene-based bisphenol monomer with pendant phenyl substituents was prepared by a facile synthetic route, from which clustered sulfonated poly(ether sulfone)s with excellent overall membrane properties were achieved for fuel cell tests. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm34414a'> </P>

Poly(arylene ether sulfone) proton exchange membranes with flexible acid side chains

Wang, Chenyi,Shin, Dong Won,Lee, So Young,Kang, Na Rae,Lee, Young Moo,Guiver, Michael D. Elsevier 2012 Journal of membrane science Vol.405 No.-

<P><B>Graphical abstract</B></P><P><ce:figure id='fig0005'></ce:figure></P><P><B>Highlights</B></P><P>► Poly(arylene ether sulfone) PEMs with two or four flexible sulfobutyl groups. ► Excellent balance between proton conductivity and dimensional swelling. ► Nanophase separated morphology with interconnected hydrophilic clusters of 1–3nm. ► Better conductivity-swelling behavior compared with analogous poly(arylene ether sulfone)s with inflexible side-chain sulfonic acid.</P> <P><B>Abstract</B></P><P>New monomers containing two or four pendent methoxyphenyl groups were synthesized by bromination of bis(4-fluorophenyl)sulfone, followed by Suzuki coupling with 4-methoxybenzeneboronic acid. Copoly(arylene ether sulfone)s containing methoxyphenyl groups (2-MPAES-<I>xx</I> and 4-MPAES-<I>xx</I>) based on the corresponding monomers were prepared by aromatic nucleophilic substitution (SNAr) polycondensation. After demethylation of the methoxy group to the reactive hydroxyl group, the respective side chain-type sulfonated copolymers (2-SPAES-<I>xx</I> and 4-SPAES-<I>xx</I>) were obtained by sulfobutylation. Flexible and tough membranes having good mechanical strength were obtained by solution casting of all copolymers. The sulfonated copolymers with two or four pendent sulfobutoxyphenyl groups had high proton conductivities in the range of 0.108–0.258S/cm for 2-SPAES-<I>xx</I> and 0.135–0.194S/cm for 4-SPAES-<I>xx</I> at 80°C, respectively. The methanol permeabilities of these membranes were in the range of 1.59×10<SUP>−7</SUP>–4.69×10<SUP>−7</SUP>cm<SUP>2</SUP>/s, which is much lower than Nafion<SUP>®</SUP> (15.5×10<SUP>−7</SUP>cm<SUP>2</SUP>/s). 2-SPAES-<I>xx</I> and 4-SPAES-<I>xx</I> display comparatively better balance between proton conductivity and water swelling than the analogous poly(arylene ether sulfone)s containing pendent sulfophenyl groups. A combination of high proton conductivities, low water uptake, and low methanol permeabilities for some of the obtained copolymers indicated that they have some of the requisite properties for proton exchange membranes in fuel cell applications.</P>

Enhancement of Proton Transport by Nanochannels in Comb‐Shaped Copoly(arylene ether sulfone)s

Li, Nanwen,Wang, Chenyi,Lee, So Young,Park, Chi Hoon,Lee, Young Moo,Guiver, Michael D. WILEY‐VCH Verlag 2011 Angewandte Chemie Vol.123 No.39

<P><B>Frisierte Membran</B>: Kammförmige Copolymere mit Poly(arylenethersulfon)‐Rückgrat (PAES) und hoch sulfonierten Poly(phenylenoxid)‐Seitenketten (PPO) bilden Nanokanal‐Morphologien (siehe Bild) für einen effizienten Protonentransport. Ihre Protonenleitfähigkeit ist bei partieller Hydratisierung entschieden höher als bei typischen Kohlenwasserstoffpolymer‐Elektrolyten. SA: Sulfonsäuregruppe.</P>

Layered 50Cr6Ni2/Stellite X-40 Multi-material Fabricated by Direct Laser Deposition: Characterization and Properties

Hongjie Wu,Suiyuan Chen,Chenyi Zhang,Jing Liang,Changsheng Liu,Mei Wang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.1

Fretting damage under high temperature corrosion and wear condition is one of the main factors that cause the failure of thekey parts of mechanical and electrical equipment, and laser cladding wear-resistant and corrosion-resistant coating is the maintechnology to repair these failure key parts. In this paper, the layered 50Cr6Ni2/Stellite X-40 multi-material was prepared bydirect laser deposition (DLD) using wear-resistant Fe-based alloy and corrosion-resistant Co-based alloy, to meet the needsof repair and remanufacturing of key parts with fretting damage. The results show that the layered 50Cr6Ni2/Stellite X-40composite material retains their respective microstructures and excellent properties. The microstructure of the 50Cr6Ni2layer mainly contains martensite and granular bainite, the microstructure of the Stellite X-40 layer consists of dendrite andeutectic structure. The layered 50Cr6Ni2/Stellite X-40 composite material has both good wear resistance (wear mass loss is1.0 mg) and good corrosion resistance (− 0.37549 of Ecorrand 0.00032 of icorr). The DLD layered 50Cr6Ni2/Stellite X-40composite material could meet the demand of short stress path rolling mill remanufacturing.

PhenyltrimethylammoniumFunctionalized Polysulfone Anion Exchange Membranes†

Li, Nanwen,Zhang, Qiang,Wang, Chenyi,Lee, Young Moo,Guiver, Michael D. American ChemicalSociety 2012 Macromolecules Vol.45 No.5

<P>Anion exchange membrane (AEM) materials were preparedfrom commercial polysulfone (PSf) by functionalization with tertiaryamines via lithiation chemistry. By optimizing the reaction conditions,a degree of substitution (DS) of 0.81 could be achieved without evidentpolymer decomposition or cross-linking. The PSf containing pendentbis(phenyldimethylamine) substituents were then quaternized with CH<SUB>3</SUB>I and ion exchange reaction to provide bis(phenyltrimethylammonium)(PTMA) polymer with hydroxide-conductive properties. Flexible andtough membranes with various ion exchange capacities (IEC)s couldbe prepared by casting the polymers from DMAc solutions. The ionomericmembranes showed considerably lower water uptake (less than 20%),and thus dimensional swelling in water, compared with many reportedAEMs. The hydroxide conductivities of the membranes were above 10mS/cm at room temperature. The unusually low water uptake and goodhydroxide conductivity may be attributed to the “side-chain-type”structures of pendent functional groups, which facilitate ion transport.Although the PTMA substituents on the AEM were found to have insufficientlong-term stability for alkaline fuel cell application, the investigationgives some insight and directions for polymeric designs by postfunctionalization.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mamobx/2012/mamobx.2012.45.issue-5/ma202681z/production/images/medium/ma-2011-02681z_0005.gif'></P>

Meshing characteristics of spur gear pairs with tooth modification under different assembly errors and sensitivity analysis for impact factors

Zhifang Zhao,Yang Yang,Hui Ma,Haixu Wang,Hongxu Tian,Chenyi Han 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.1

Assembly errors may change contact state of gear pairs, then induce failure and vibration. To reveal the effects of assembly errors and tooth modification on the meshing characteristics, the loaded tooth contact analysis (LTCA) is conducted through an improved algorithm. The time-varying meshing stiffness (TVMS), static transmission error (STE) and contact stress (CS) are calculated considering assembly errors and tooth modification. Then, sensitivity of meshing characteristics to coupling assembly errors are investigated based on the design of orthogonal experiment (DOE). The meshing characteristic analysis results show that assembly errors have a significant effect on mesh characteristics of the gear pair. The results of sensitivity analysis indicate that the meshing characteristic is the most sensitive to axial deviation for the model used in this paper.

Improved Fluorescence of Fluorene Polymer in Solid State

Xiaoyan Zhao,Shuai Zhang,Chen Huang,Chenyi Wang 한국섬유공학회 2019 Fibers and polymers Vol.20 No.10

Fluorene-containing poly(aryl ether nitrile) (FPAN) was prepared by a typically aromatic nucleophilic substitutionpolymerization. The chemical structure of FPAN was confirmed by FTIR and 1H NMR spectroscopy. Different morphologiesof FPAN fibers could obtain through electrospinning. The light-emission properties of polymer in solution, casting film andfibrous membrane were examined by spectrofluorometry. This polymer had good thermal properties with glass-transitiontemperatures at 280 oC and 10 % weight loss temperatures in the range of 497-502 oC. Additionally, the contact angles in thethin-film state and electrospun fiber membranes were examined. The water contact angle of fiber membrane was improvedcompared to that of casting film which could reach to the 137 o. The resulting material exhibited stable luminescent intensity,possessed considerable thermal stability, and could be facilely processed into device for optical field applications.

Hydrocarbon-based Polymer Electrolyte Membranes for Fuel Cells

Michael D. Guiver,Nanwen Li,Chenyi Wang,Young Moo Lee 한국에너지학회 2010 한국에너지공학회 학술발표회 Vol.2010 No.10

Crack Analysis of Multi-plate Intersection WeldedStructurein Port MachineryUsing Finite Element Stress Calculation andAcoustic Emission Testing

LuKai-liang,ZhangWei-guo,ZhangYe,HuangHui,ChenYi-sheng,LiWen-yuan,Wang Chao 보안공학연구지원센터 2014 International Journal of Hybrid Information Techno Vol.7 No.5