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Xing’an Zhao,Biao Huang,Tairan Chen,Guoyu Wang,Deming Gao,Jing Zhao 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2
We used computational modeling to investigate the cavitation performance of an aviation fuel pump, and optimize structural parameters using the surrogate-based method. In the numerical simulation, a rotation-curvature correction was adapted to the k-ε turbulence model, and a four-component surrogate fuel was selected to reproduce the physical properties of the China RP-3 kerosene. Then the performance of the aviation fuel pump was predicted. In the optimization, based on the series of the numerical results, Surrogate-based analysis and optimization (SBAO) was used to optimize the structural parameters of the fuel pump (the variation of the outlet blade angle for the inducer △β b1 and the variation of the inlet blade angle for the impeller △β b2 ). The results show that the prediction of cavitation performance agrees well with the experimental data. The results show that cavitation areas are mainly distributed in the inlet of the inducer. The volume of cavities grows with the decreasing NPSHa. The head of the fuel pump has a sudden head-drop when NPSHa ≤ 5.64 m. Furthermore, the surrogate-based approach is available in structural optimization of the fuel pump. The cavitation performance of the optimized pump improved about 22 % with a little drop of head coefficient when △β b1 = 4.33° and △β b2 = 3.24°. The numerical approach employed in this paper can accurately predict the cavitating flow of the high rotating speed fuel pump and the surrogate-based method is available in the structural optimization for a better cavitation performance.
Analyzing Errors Made by Eighth-Grade Students in Solving Geometrical Problems
( Huang Xing Feng ),( Cheng Long Hai ) 한국수학교육학회 2011 수학교육연구 Vol.15 No.4
In mathematical problem solving, students may make various errors. In order to draw useful lessons from the errors, and then correct them, we surveyed 24 eighth-grade students` performances in geometrical problem solving according to Casey`s hierarchy of errors. It was found that: 1. Students`` effect can lead to errors at the stage of "comprehension", "strategy selection", and "skills manipulation"; and 2. Students`` geometric schemas also influenced their strategy selection".
Huang, Xing-Jiu,Li, Yue,Im, Hyung-Soon,Yarimaga, Oktay,Kim, Ju-Hyun,Jang, Doon-Yoon,Cho, Sung-Oh,Cai, Wei-Ping,Choi, Yang-Kyu IOP Pub 2006 Nanotechnology Vol.17 No.12
<P>Large-scale morphology-controlled SWCNT/polymeric microsphere arrays can be obtained by a wet chemical self-assembly technique. The loading of SWCNTs, the length of SWCNTs, and the size and nature of polymeric microspheres can easily be controlled. Similar results can also be reached using this method for MWCNTs. In both types of CNTs, they form an interesting interactive ‘net’ structure on spheres and sphere joints. The SWCNT/PS-modified Au electrode was used for detection of uric acid by cyclic voltammetry and single-potential time-based techniques. The preliminary results show that the modified electrode presents good sensitivity and stability to uric acid. </P>
“Lock-and-Key” Geometry Effect of Patterned Surfaces: Wettability and Switching of Adhesive Force
Huang, Xing-Jiu,Kim, Dong-Haan,Im, Maesoon,Lee, Joo-Hyung,Yoon, J.-B.,Choi, Yang-Kyu WILEY-VCH Verlag 2009 Small Vol.5 No.1
<B>Graphic Abstract</B> <P>A new type of “lock-and-key” patterned surface consisting of dense arrays of microfabricated PDMS lens and bowl arrays (see image) without silanization for the wettability and switching of adhesive forces is presented. The microlens-arrayed surface (lock) shows a low contact angle and a high adhesive force following the Wenzel state, whilst the imprinted microbowl-arrayed surfaces (key), which were replicas of the microlenses, exhibit a high contact angle and an anti-adhesive behavior following the Cassie–Baxter state. <img src='wiley_img/16136810-2009-5-1-SMLL200800649-content.gif' alt='wiley_img/16136810-2009-5-1-SMLL200800649-content'> </P>
Huang, Xing-Jiu,Yarimaga, Oktay,Kim, Ju-Hyun,Choi, Yang-Kyu Royal Society of Chemistry 2009 Journal of materials chemistry Vol.19 No.4
<P>The effects of substrate surface roughness on the directed electrodeposition of gold 3-D complex nanoarchitectures with hedgehog-shaped, cauliflower-shaped, or bunch-of-grapes-shaped surface features are revealed. The surface morphology of the synthesized particles was observed using a scanning electron microscope (SEM). Their chemical composition was confirmed using X-ray diffraction (XRD) patterns. The surfaces of ITO/glass substrate with different roughness were checked using atomic force microscopy (AFM) and contact angle measurements. Effects of variation of the deposition potential on the growth of Au nanocomplex structure have provided valuable information to clarify the substrate surface roughness-dependent 3-D nanocomplex synthesis. Pt/Au bimetallic particles with different surface features were produced under the same experimental conditions using mentioned different rough ITO/glass substrates. The growth follows a diffusion controlled mechanism. Electrochemical experimental results demonstrated that such hedgehog-shaped Au particles exhibit enhanced voltammetric responses. These findings offer insight into the electrosynthesis of complex micro/nano-structures. Interesting 3-D nanostructures can be realized by controlling the surface roughness of the substrate.</P> <P>Graphic Abstract</P><P>Gold 3-D complex nanoarchitectures with hedgehog-shaped, cauliflower-shaped, or bunch-of-grapes-shaped surface features can be electrosynthesized on ITO/glass substrates with different surface roughnesses. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b816835k'> </P>
Huang, Xing,Liu, Zhongqiang,Millet, Marie-Mathilde,Dong, Jichen,Plodine, Milivoj,Ding, Feng,Schlö,gl, Robert,Willinger, Marc-Georg American Chemical Society 2018 ACS NANO Vol.12 No.7
<P>The properties of nanocrystals are highly dependent on their morphology, composition, and structure. Tailored synthesis over these parameters is successfully applied for the production of nanocrystals with desired properties for specific applications. However, in order to obtain full control over the properties, the behavior of nanocrystals under external stimuli and application conditions needs to be understood. Herein, using Ag-NiP<SUB><I>x</I></SUB> nanocrystals as a model system, we investigate the structural evolution upon thermal treatment by <I>in situ</I> aberration-corrected scanning transmission electron microscopy. A combination of real-time imaging with elemental analysis enables the observation of the transformation from a Ag-NiP<SUB><I>x</I></SUB> core-shell configuration to a Janus structure at the atomic scale. The transformation occurs through dewetting and crystallization of the NiP<SUB><I>x</I></SUB> shell and is accompanied by surface segregation of Ag. Further temperature increase leads to a complete sublimation of Ag and formation of individual Ni<SUB>12</SUB>P<SUB>5</SUB> nanocrystals. The transformation is rationalized by theoretical modeling based on density functional theory calculations. Our model suggests that the transformation is driven by changes of the surface energy of NiP<SUB><I>x</I></SUB> and the interfacial energy between NiP<SUB><I>x</I></SUB> and Ag. The direct observation of atomistic dynamics during thermal-treatment-induced structural modification will help to understand more complex transformations that are induced by aging over time or the interaction with a reactive gas phase in applications such as catalysis.</P> [FIG OMISSION]</BR>
( Xing Hu ),( Linhua Ma ),( Shaocheng Huang ),( Jinke Huang ),( Kangning Sun ),( Tianyu Huang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.8
In high diversity node situation, single-channel MAC protocols suffer from many collisions. To solve this problem, the research of multichannel MAC protocol has become a hotspot. And the cyclic quorum-based multichannel (CQM) MAC protocol outperformed others owing to its high frequency utilization. In addition, it can avoid the bottleneck that others suffered from and can be easily realized with only one transceiver. To obtain the accurate performance of CQM MAC protocol, a Markov chain model, which combines the channel hopping strategy of CQM protocol and IEEE 802.11 distributed coordination function (DCF), is proposed. The metrics (throughput and average packet transmission delay) are calculated in performance analysis, with respect to node number, packet rate, channel slot length and channel number. The results of numerical analysis show that the optimal performance of CQM protocol can be obtained in saturation bound situation. And then we obtain the saturation bound of CQM system by bird swarm algorithm (BSA). Finally, the Markov chain model and saturation bound are verified by Qualnet platform. And the simulation results show that the analytic and simulation results match very well.