Procedia IUTAM最新文献

{"title":"Nanocontact Disorder in InP Nanowire Devices for the Enhancement of Visible Light and Oxygen Gas Sensitivities","authors":"Yen-Fu Lin ,&nbsp;Chia-Hung Chang ,&nbsp;Tsu-Chang Hung ,&nbsp;Zhaoping Liu ,&nbsp;Jiye Fang ,&nbsp;Wen-Bin Jian","doi":"10.1016/j.piutam.2017.03.034","DOIUrl":"10.1016/j.piutam.2017.03.034","url":null,"abstract":"<div><p>InP nanowires, synthesized through a self-seeded growth approach, are used in the fabrication of field-effect transistors which consist of source, drain, and back-gate electrodes. The weak gating voltage dependence implies low carrier concentrations whereas its behavior reveals native <em>n</em>-type doping in InP nanowires. These InP nanowire devices exhibit a vast variation of room-temperature resistance that raises a question about contact resistance. For devices of low room-temperature resistance, electron transport in InP nanowires is investigated using temperature dependent resistance in the temperature range between 80 and 300 K, and it can be analyzed using the model of thermal activation. For other devices of high room-temperature resistance, we take into account nanocontact resistance. Models of both Schottky contact and Mott's variable range hopping (VRH) are considered. The two resistances are connected in parallel to give total contact resistance of InP nanowire devices. After fitting experimental data by the proposed model, we estimate effective Schottky barriers and disorder contributions to nanocontact resistance. The effective Schottky barrier, and the nanocontact Schottky and Mott's VRH resistances are plotted as a function of the device room-temperature resistance which indicates the scale of disorder. Using room-temperature resistance of InP nanowire devices, the devices are classified into nanowire- or contact-dominated devices. The two different class of devices are used to check their photo- and gas-sensitivities. The contact-dominated InP nanowire devices show low dark current and low photocurrent as usual, but these contact-dominated devices give high ratio of photo- to dark-current. That result reveals a high photo-sensitivity for those devices of high nanocontact resistance. On the other hand, for gas sensing experiments, the contact-dominated devices show as well a high ratio of resistance under O₂ to that under N₂ gas exposure.</p></div>","PeriodicalId":74499,"journal":{"name":"Procedia IUTAM","volume":"21 ","pages":"Pages 33-39"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.piutam.2017.03.034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55245667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Flexoelectric Effects on Current-voltage Characteristic of Polydomain in Ferroelectric Thin Films","authors":"Limei Jiang ,&nbsp;Xiaofei Xu ,&nbsp;Yichun Zhou","doi":"10.1016/j.piutam.2017.03.037","DOIUrl":"10.1016/j.piutam.2017.03.037","url":null,"abstract":"<div><p>Strain gradients at domain walls in polydomain ferroelectric thin films generally are huge, reaching a value of 10⁷-10⁸ m^-1, appears at domain walls. These huge strain gradients always play a considerable impact on polarization distribution via flexoelectricity. However, the ability of the flexoelectricity to tune the leakage current in ferroelectric nanofilms is untouched to date. By combining the phase field model and diffusion equations for an electron/electron hole, a self-consistent model is established to investigate the influence of flexoelectric effect on the current-voltage characteristic of Pt/Pb(Zr_0.1Ti_0.9)O₃/Pt capacitor. It is shown that the longitudinal flexoelectric coefficient related coupling type would reduce the electric potential, and thus, increase the electron hole concentration and cause leakage current increasing in thin films. In contrast, the transverse flexoelectric coefficient related coupling type would raise the electric potential, decrease the electron hole concentration and cause leakage current decreasing in thin films.</p></div>","PeriodicalId":74499,"journal":{"name":"Procedia IUTAM","volume":"21 ","pages":"Pages 56-62"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.piutam.2017.03.037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55245782","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Underwater Superhydrophobiciy: Fundamentals and Applications","authors":"Huiling Duan","doi":"10.1016/j.piutam.2017.03.018","DOIUrl":"10.1016/j.piutam.2017.03.018","url":null,"abstract":"<div><p>Bioinspired superhydrophobic surfaces have attracted great interests from fundamental researches to engineering applications. The functionality of superhydrophobicity, especially for an underwater situation, depends on a large area fraction of entrapped liquid-gas interfaces, which, however, are subject to instabilities induced by various physical phenomena, such as pressurization, air diffusion, fluid flow, and condensation. The wetting states strongly affssect the functionality of superhydrophobic surface, like liquid slippage and cavitation. The current work is dedicated to elucidating the underlying mechanisms of stability and wetting transition of underwater superhydrophobicity, providing novel strategies for durable and robust design, and introducing the applications in drag reduction and cavitation control.</p></div>","PeriodicalId":74499,"journal":{"name":"Procedia IUTAM","volume":"20 ","pages":"Pages 128-135"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.piutam.2017.03.018","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55245061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of GaSb:Te Crystal Growth in Space Experiment","authors":"Anatoly I. Prostomolotov ,&nbsp;Nataliya A. Verezub ,&nbsp;Alexey E. Voloshin ,&nbsp;Tatau Nishinaga","doi":"10.1016/j.piutam.2017.06.004","DOIUrl":"10.1016/j.piutam.2017.06.004","url":null,"abstract":"<div><p>An application of X-ray topography methods allowed us to construct a two-dimensional map of the impurity distribution in a GaSb:Te crystal grown under microgravity conditions. This map served as a framework for the analysis of crystal growth features and of the impurity inhomogeneity in the crystal. The data on the impurity distribution in the sample became an experimental basis for the analysis of the crystallization parameters (the crystal growth rate and the maximum convection velocity) and an adequate application of theoretical models (analytical and numerical) to explaining the mechanisms of onset of impurity inhomogeneities in the crystal.</p></div>","PeriodicalId":74499,"journal":{"name":"Procedia IUTAM","volume":"23 ","pages":"Pages 42-51"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.piutam.2017.06.004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55246155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soft Machines: Challenges to Computational Dynamics","authors":"Haiyan Hu,&nbsp;Qiang Tian,&nbsp;Cheng Liu","doi":"10.1016/j.piutam.2017.03.003","DOIUrl":"10.1016/j.piutam.2017.03.003","url":null,"abstract":"<div><p>The paper surveys the recent studies of authors on the dynamic modeling and simulation of soft machines in the frame of multibody system dynamics. The studies focus on the geometric nonlinearity of coupled overall motion and large deformation of a soft body, the physical nonlinearity of a soft body made of hyper-elastic or elastoplastic materials, the frictional impacts and contacts of soft bodies, and the efficient dynamic computation algorithm of soft multibody systems governed by a set of differential-algebraic equations of very high dimensions. The paper presents the validation of proposed approach through three case studies, including the locomotion of a soft quadrupedal robot, the spinning deployment of a solar sail of spacecraft, and the deployment of a mesh reflector of satellite antenna, as well as the corresponding experimental studies. Finally, the paper gives some remarks on future researches.</p></div>","PeriodicalId":74499,"journal":{"name":"Procedia IUTAM","volume":"20 ","pages":"Pages 10-17"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.piutam.2017.03.003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55244049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact Loading on Nanocomposites in Thermal Environment","authors":"G. Balaganeshan ,&nbsp;M. Pushparaja ,&nbsp;R. Velmurugan ,&nbsp;N.K. Gupta","doi":"10.1016/j.piutam.2017.06.022","DOIUrl":"10.1016/j.piutam.2017.06.022","url":null,"abstract":"<div><p>This study investigates energy absorption of thermally loaded composites and nanocomposites laminates during impact loading. The laminates are prepared by glass fiber/epoxy with and without nano particles in the matrix system. Nano clay and carbon nano tube are used as filliers in the epoxy matrix. The composites specimens are subjected to impact loading at 0° C, 30° C and 60° C temperature environments. A gas gun impact testing facility is used for propelling the projectile of mass 7.6 g and diameter 9.5 mm with hemi spherical nose. The initial and residual velocities of projectile are predicted to find the energy absorbing capacity of laminates. The energy absorption and delamination area of the specimens are analyzed and discussed for the laminates with and without clay. Also, the ballistic limit is predicted for the specimens of nanocomposites made with glass fibers and epoxy matrix, and the effect of temperature on impact resistance is discussed. Analytical model is developed and the energy absorption characteristics are also studied.</p></div>","PeriodicalId":74499,"journal":{"name":"Procedia IUTAM","volume":"23 ","pages":"Pages 210-219"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.piutam.2017.06.022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55246670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nonlinear Acoustic Waves in Solids with Dislocations","authors":"Vladimir I. Erofeev,&nbsp;Alexey Malkhanov","doi":"10.1016/j.piutam.2017.06.024","DOIUrl":"10.1016/j.piutam.2017.06.024","url":null,"abstract":"<div><p>Propagation of a plane longitudinal acoustic wave in a solid with dislocations is theoretically studied. The effect of dislocations on the phase velocity dispersion and the character and degree of wave damping is analyzed. The following results are obtained. The phase velocity exhibits infinite growth at zero frequency and asymptotically approaches the tabulated value for the longitudinal wave velocity in solids as the frequency tends to infinity. The frequency dependence of the wave damping coefficient has a peak whose position depends on the characteristics of the solid. The results are compared with experimental data for the dislocation relaxation process in lead and are found to be in good agreement with these.</p><p>The influence of the dislocation structure on the character of the dependencies obtained for wave damping and phase velocity dispersion is analyzed. The results are compared with experimental data for the dislocation damping during plastic deformation and cycling loading of polycrystalline copper and aluminum.</p><p>We derive the dynamic equations of solid media with dislocations containing geometrical and physical nonlinearity. The evolution of nonlinear acoustical waves under the influence of a dislocation field is studied. The development of modulation instability quasiharmonic longitudinal waves is shown to be possible.</p></div>","PeriodicalId":74499,"journal":{"name":"Procedia IUTAM","volume":"23 ","pages":"Pages 228-235"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.piutam.2017.06.024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55246715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"State Dependent Delayed Drill-string Vibration: Theory, Experiments and New Model","authors":"M. Wiercigroch ,&nbsp;K. Nandakumar ,&nbsp;L. Pei ,&nbsp;M. Kapitaniak ,&nbsp;V. Vaziri","doi":"10.1016/j.piutam.2017.08.007","DOIUrl":"10.1016/j.piutam.2017.08.007","url":null,"abstract":"<div><p>We have reviewed the development and the analysis of the coupled two degrees-of-freedom model of drill-string vibration, which assumes a state-dependent time delay and a viscous damping for both the axial and torsional vibration. This model corrects the instability deficiencies of the previous models but it is still based on a uniform angular distribution of blades on a drill-bit, which can lead to unrealistic regenerative types of instability. However, the model sheds some lights on the origin and the interplay between stick-slip and bit-bounce, the dangerous dynamic phenomena encountered during rotary drilling. The experimental rig developed by the Centre of Applied Dynamics Research at the University of Aberdeen is used to show some shortcomings of this model and to develop a new more realistic one. The new model assuming a non-uniform distribution of blades for drag type drill-bits is proposed.</p></div>","PeriodicalId":74499,"journal":{"name":"Procedia IUTAM","volume":"22 ","pages":"Pages 39-50"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.piutam.2017.08.007","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55247270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Noise Correction Embedded Identification Approach for Delays and Parameters in Nonlinear Delay Systems","authors":"Xiaoxu Zhang,&nbsp;Jian Xu","doi":"10.1016/j.piutam.2017.08.010","DOIUrl":"10.1016/j.piutam.2017.08.010","url":null,"abstract":"<div><p>To identify unknown parameters from the noise-polluted measurement in time-delayed systems, this paper proposes the incremental harmonic balance based approach. By assuming that the steady response is periodic and the noise pollution does not change the periodicity of the measured response, this approach expands the ideal and measured response into the form of Fourier series. With this process, the noise correction can be parameterized as the harmonic increments of the measured response so that the noise correction can be determined by the same process of the identification of the unknown parameters. Numerical examples are given to verify the efficiency of the proposed approach. In comparison with the identified parameters without noise correction, the results show that the accuracy of the ones with noise correction is significantly improved. This achievement also implies that the proposed approach is reliable in similar cases of engineering applications.</p></div>","PeriodicalId":74499,"journal":{"name":"Procedia IUTAM","volume":"22 ","pages":"Pages 67-74"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.piutam.2017.08.010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55247439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Protein Mechanics: From Amino Acid to Swimming Cells","authors":"Patrick Onck","doi":"10.1016/j.piutam.2017.03.010","DOIUrl":"10.1016/j.piutam.2017.03.010","url":null,"abstract":"<div><p>This proceedings paper contains a review of the work presented in the Sectional Lecture in Solids on August 25 at ICTAM 2016. -- Proteins are long polypeptide chains of amino acids and their structure and biological function are directly related to their amino acid sequence. I will discuss three different biological functions that are dominated by protein mechanics, each at their own specific time and length scale. To relate structure to function, multiscale computational models have been developed for (i) cilia and flagella, (ii) actin filament networks and (iii) the nuclear pore complex.</p></div>","PeriodicalId":74499,"journal":{"name":"Procedia IUTAM","volume":"20 ","pages":"Pages 73-80"},"PeriodicalIF":0.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.piutam.2017.03.010","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55244555","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}