http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Sun, Xiuxuan,Wu, Qinglin,Zhang, Jinlong,Qing, Yan,Wu, Yiqiang,Lee, Sunyoung Elsevier 2017 Materials & Design Vol.114 No.-
<P><B>Abstract</B></P> <P>Cellulose nanofibers (CNFs) were prepared through acid hydrolysis and used in combination with graphene nano-platelets (GNPs) as modifiers for oil well cement (OWC). The rheology behavior of CNF/GNP-OWC slurries at three temperatures (i.e., 20, 40, and 60°C) was measured and modeled using four different rheological models. Thermal properties, surface functional groups, morphology, and mechanical performance of the composites were characterized. CNF/GNP-OWC slurry exhibited a typical shear-thinning behavior with reduced shear viscosity at higher shear rates. The use of CNFs and GNPs led to increased yield stresses of fresh CNF/GNP-OWC slurry and temperature significantly influenced the yield stress values. Among these rheology models, the Vom Berg model exhibits the best fitting result of the slurry rheology data (R<SUP>2</SUP> =0.999). The addition of CNFs and GNPs increased degree of hydration (DOH) value of CNF/GNP-OWC composites. Both flexural and compressive strengths of the CNF/GNP-OWC composites were enhanced with added CNFs and GNPs. The reinforcing mechanism was attributed to the increased DOH, reduced pores, and bridging effect of CNFs and GNPs in the composites.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cellulose nanofibers (CNFs) and graphene nanoplatelets (GNPs) reinforced oil well cement (OWC) composites were prepared and characterized. </LI> <LI> Vom Berg model provided the best fitting to measured rheology data of OWC slurry. </LI> <LI> CNFs and GNPs enhanced flexural and compressive strengths of OWC. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Thermal degradation and flammability behavior of fire-retarded wood flour/polypropylene composites
Sun, Lichao,Wu, Qinglin,Xie, Yanjun,Cueto, Rafael,Lee, Sunyoung,Wang, Qingwen Technomic Publising 2016 Journal of Fire Sciences Vol.34 No.3
<P>Magnesium hydroxide, expandable graphite, and ammonium polyphosphate were used to enhance the thermal stability and fire retardant properties on wood flour/polypropylene composites. The thermal decompositions and flammability properties were investigated using modulated thermogravimetric analysis and cone calorimeter, and the activation energy of each decomposition process was also determined by modulated thermogravimetric analysis. The results showed that both expandable graphite and ammonium polyphosphate promoted thermal degradation of wood flour and char formulation, and magnesium hydroxide did not influence on the wood flour decomposition. Unlike in nitrogen atmosphere, magnesium hydroxide and ammonium polyphosphate increased the peak temperature of wood flour thermal degradation and diminished the decomposition peaks of polypropylene in air atmosphere. Cone calorimeter results showed that expandable graphite greatly reduced the heat and smoke release. A general activation energy range of 187-226kJmol(-1) (in nitrogen), 165-206kJmol(-1) (in air) at wood flour degradation stage, 237-262kJmol(-1) (in nitrogen), and 185-269kJmol(-1) (in air) at polypropylene degradation stage were proposed for wood flour/polypropylene composite with and without fire retardants.</P>
Effects of Grain Refinement on Rollability of AZ31 Mg Alloy
Jin, Qinglin,Lim, Su Gun,You, Bong Sun Trans Tech Publications, Ltd. 2005 Materials science forum Vol.475 No.-
<P>The initial coarse grain size of 400㎛ of a as-cast AZ31 alloy was refined to 130㎛ by carbon addition method. The microstructural evolution, recrystallization, edge cracking phenomena of the coarse grained AZ31 alloy during hot rolling were investigated and compared with those of grain refined AZ31 alloy.</P>
Huixuan Zhuang,Qinglin Sun,Zengqiang Chen,Xianyi Zeng 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.11
In this paper, a novel attitude control method for nonlinear missile system is proposed, which combines backstepping technique with linear active disturbance rejection control (LADRC). Firstly, the nonlinear missilemodel is introduced and transformed into the standard state equation. The linear extended state observer (LESO) is used to estimate the unknown variables. Compared with PID control method, the homologous LADRC designensures that the state variables of the closed-loop system converge to the reference state. The stability of LESO and LADRC is theoretically analyzed and proved. A large number of comparative simulations show the effectiveness ofthe method. The simulation results show that LADRC has better control performance than SMC and PID method.
Huixuan Zhuang,Qinglin Sun,Zengqiang Chen,Xianyi Zeng 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.6
Robust flight control laws based on back-stepping technology and ADRC method are designed for attitude control of a non-linear aircraft system. First, non-linear aircraft model is introduced and converted to standard equation of state. Then, the extended state observer is applied to estimate the unknown variables, the homologous ADRC is designed to ensure the state variables of the CLS to astringe to the reference state. Next, the stability of ESO and ADRC are analyzed and proven theoretically. At last, the effectiveness of this method is illustrated by extensive comparative simulations. The results acquired from simulation attest that ADRC can achieve better control performance than PID and SMC method.
Xu, Yanjun,Lee, Sun‐,Young,Wu, Qinglin Wiley Subscription Services, Inc., A Wiley Company 2011 Polymer composites Vol.32 No.5
<P><B>Abstract</B></P><P>The effect of chemical treatment at fiber–plastic interface and fiber loading level on creep property of bamboo fiber high‐density polyethylene (BF/HDPE) composites was investigated. For single modifier systems, the use of maleic anhydride grafted polyethylene (PE‐<I>g</I>‐MA) as a coupling agent helped reduce the creep and achieved the optimum effect at the 5.7% loading level. The addition of either a semicrystalline or an amorphous MA grafted ethylene propylene rubber (sEPR‐<I>g</I>‐MA or aEPR‐<I>g</I>‐MA) as an impact modifier increased the creep. For the combined modifiers, the use of PE‐<I>g</I>‐MA in EPR‐<I>g</I>‐MA modified composites gradually improved creep performance. Four‐element Burgers model was shown to fit measured creep data well only within the specified test period. However, both partially stretched Burgers (PSB) model and fully stretched Burgers (FSB) model could be applied for characterization and prediction when the stretching exponent was fixed at certain given values. The FSB model offered a better long‐term prediction based on the short‐term creep data. Time‐temperature superposition technique produced smooth master creep curves through horizontal shifts, but it slightly over‐predicted the long‐term creep for most composite systems. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers</P>
Grey Wolf Optimization based Active Disturbance Rejection Control Parameter Tuning for Ship Course
Jia Ren,Zengqiang Chen,Yikang Yang,Mingwei Sun,Qinglin Sun,Zenghui Wang 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.3
It is important to control the ship course in complicated ocean environment. In this paper, a Grey Wolf Optimization (GWO) based Active Disturbance Rejection Control (ADRC) tuning method is proposed in the application of the ship course. Here, GWO is used to tune the parameters of ADRC. To validate the performance of the proposed method, some simulations have been carried out and the results are compared with the results of other tuning methods, such as, Harris Hawks Optimization (HHO), Particle Swarm Optimization (PSO), Q-learning and manual tuning. To test the stability of different tuning methods, the cases of no disturbance, constant value disturbance, second-order wave force disturbance, white noise disturbance and mixed disturbance are considered. The robustness of the system for parameters perturbation is analyzed. The research indicates that the GWO based ADRC can achieve better performance than other methods.
Heterolayered, One-Dimensional Nanobuilding Block Mat Batteries
Choi, Keun-Ho,Cho, Sung-Ju,Chun, Sang-Jin,Yoo, Jong Tae,Lee, Chang Kee,Kim, Woong,Wu, Qinglin,Park, Sang-Bum,Choi, Don-Ha,Lee, Sun-Young,Lee, Sang-Young American Chemical Society 2014 NANO LETTERS Vol.14 No.10
<P>The rapidly approaching smart/wearable energy era necessitates advanced rechargeable power sources with reliable electrochemical properties and versatile form factors. Here, as a unique and promising energy storage system to address this issue, we demonstrate a new class of heterolayered, one-dimensional (1D) nanobuilding block mat (<I>h</I>-nanomat) battery based on unitized separator/electrode assembly (SEA) architecture. The unitized SEAs consist of wood cellulose nanofibril (CNF) separator membranes and metallic current collector-/polymeric binder-free electrodes comprising solely single-walled carbon nanotube (SWNT)-netted electrode active materials (LiFePO<SUB>4</SUB> (cathode) and Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> (anode) powders are chosen as model systems to explore the proof of concept for <I>h</I>-nanomat batteries). The nanoporous CNF separator plays a critical role in securing the tightly interlocked electrode–separator interface. The SWNTs in the SEAs exhibit multifunctional roles as electron conductive additives, binders, current collectors and also non-Faradaic active materials. This structural/physicochemical uniqueness of the SEAs allows significant improvements in the mass loading of electrode active materials, electron transport pathways, electrolyte accessibility and misalignment-proof of separator/electrode interface. As a result, the <I>h</I>-nanomat batteries, which are easily fabricated by stacking anode SEA and cathode SEA, provide unprecedented advances in the electrochemical performance, shape flexibility and safety tolerance far beyond those achievable with conventional battery technologies. We anticipate that the <I>h</I>-nanomat batteries will open 1D nanobuilding block-driven new architectural design/opportunity for development of next-generation energy storage systems.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/nalefd/2014/nalefd.2014.14.issue-10/nl5024029/production/images/medium/nl-2014-024029_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nl5024029'>ACS Electronic Supporting Info</A></P>