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World Environmental and Water Resources Congress 2011: Bearing Knowledge for Sustainability

作者： Zang, Chen Shang, Shiyou Wang, Xixi Wang, Zhiguo Lv, Fang Liu, Limin Inner Mongolia University of Technology Hohhot 010051 China College of Mechanical and Electrical Engineering Inner Mongolia Agricultural University Hohhot 010018 China Hydrology and Watershed Management Program Department of Engineering and Physics Tarleton State University Stephenville TX 76402 United States

ISBN: (纸本)9780784411735

Steppe grassland is one of the most precious green-vegetation renewable resources in Inner Mongolia of China as well as all over the world. Not only the grassland is the material basis for animal husbandry but it also plays an important role in sustaining the vulnerable steppe ecosystem. However, one noticeable problem is that large areas of steppe (in particular, typical) grassland are being degraded as a result of inappropriate exploitation, over-grazing, and/or climate change. For instance, 90 of the steppe grassland in China has exhibited somewhat degree of degradation. The 4000 km2 typical grassland in Ujimqin County of Inner Mongolia, which used to be very productive and self-sustainable, is losing its ecological functions. Previous research indicated that the typical grassland degradation is likely caused by the alternation of natural hydrologic conditions, which in turn may be a result of human activities and climate change as well as the interaction thereof. The objective of this study was to quantify the relation between grassland degradation and hydrology alteration. The study site was a 100 km2 experimental plot within the Ujimqin typical grassland. This study used high-resolution, multi-temporal remote sensing imageries to estimate the grassland degradation index (GDI), which is defined as the ratio of the biomass per unit grazing area to that per unit non-grazing area. The hydrology alteration is described in terms of spatial and temporal heterogeneity increases of evapotranspiration, soil moisture, and runoff, which are determined using the long-term weather and streamflow data. © 2011 ASCE.

关键词： Climate change

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SU-E-J-68: An Optical Image Guidance System: To Detect Arbitrarily Attached Markers Behind a Full Facemask

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Medical physics 2012年第6PART7期39卷 3668页

作者： H Kim Y Park T Son K Lee I Kim S Ye Interdisciplinary program in Radiation Applied Life Science College of Medicine SNU Seoul. Department of Radiation Oncology Seoul National University Hospital Seoul. School of Mechanical and Aerospace Engineering SNU Seoul. Department of Radiation Oncology College of Medicine SNU Seoul.

PURPOSE:We developed an optical image guidance system to manage patient's inter-fractional set-up errors by tracking external markers at the specific positions (e.g., nose tip) behind a full facemask. However, a problem associated with the reproducibility of the marker positions during the entire course of treatments still remains. In order to remove this disadvantage, we applied the arbitrary-point-to-plane registration method to our existing system. METHODS:Infra-red (IR) reflecting markers were attached on arbitrary positions of the head phantom's face and then the phantom was immobilized by a full face thermoplastic mask. 3D coordinates of the IR markers behind the full facemask were reconstructed by the calibrated stereo camera system using the direct linear transform (DLT) algorithm. In order to match arbitrarily attached markers with a planning CT image, rough positions of three markers were manually defined (rough registration) and then the coordinates of all markers were determined through the point-to-plane registration using the contractive projection point (CPP) algorithm (fine registration). In addition, the marker registration error in 6 DOF was calculated. In order to validate accuracy of the system, the phantom was intentionally moved according to 10 sets of known translation parameters. RESULTS:A mean target registration error (TRE) determined by the experiments for arbitrarily attached markers was 1.24 ± 0.32 mm. The fine registration following the rough registration allowed fast and robust registrations. CONCLUSIONS:The proposed solution for arbitrarily attached markers behind a full facemask enables us to avoid any daily errors in attaching the external markers at the specific positions. This work was supported in part by the SNU interdisciplinary project (2009-2010) and the SNU Brain Fusion project (2010-2011).

关键词： Brain Cameras Computed tomography Image detection systems Infrared detectors Medical imaging Optical devices Optical images

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Symmetry of atomistic structure for armchair-edge graphene nanoribbons under uniaxial strain

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applied physics Letters 2012年第15期100卷

作者： Wenhu Liao Heping Zhao Gang Ouyang Ke-Qiu Chen Guanghui Zhou 1College of Physics Mechanical and Electrical Engineering Jishou University Jishou 416000 China 2Department of Physics and Key Laboratory for Low-Dimensional Quantum Structures and Manipulation (Ministry of Education) Hunan Normal University Changsha 410081 China 3Department of Applied Physics Hunan University Changsha 410082 China 4International Center for Materials Physics Chinese Academy of Sciences Shenyang 110015 China

We present a systematic first-principles calculation on the atomistic structural variation for armchair-edge graphene nanoribbons (AGNRs) under a small planar uniaxial strain along armchair and zigzag directions, respectively. Interestingly, it is found that asymmetric AGNRs are more sensitive to the external strain with more types of carbon-carbon bonds and angles, while symmetric ones show less types of bonds and angles under the same strain. This difference is attributed to the symmetric property of AGNRs combining with the bond theory. Our findings may be useful in further understanding of GNRs under strain and in designing nanoelectromechanical devices based on GNRs.

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Grid impact indicators for active building simulation

Grid impact indicators for active building simulation

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作者： Verbruggen, B. De Coninck, R. Baetens, R. Saelens, D. Helsen, L. Driesen, J. Department of Electrical Engineering Division of Electrical Energy and Computer Architectures Katholieke Universiteit Leuven BE-3000 Leuven Belgium Department of Mechanical Engineering Division of Applied Mechanics and Energy Conversion Katholieke Universiteit Leuven BE-3000 Leuven Belgium Department of Civil Engineering Division of Building Physics Katholieke Universiteit Leuven BE-3000 Leuven Belgium 3E BE-1000 Brussels Belgium

ISBN: (纸本)9781612842189

This paper gives an overview of grid impact indicators that could be used to assess the impact of the energy exchange with a single intelligent building on the electricity grid. Seven indicators are given, the capacity factor, loss of load probability, cover factor, one percent peak power, peaks above limit, dimensioning rate and kVA credit. An example of a building simulation is used to show what these indicators can teach us. For this example the indicators are calculated and an explanation of what they show is given. Finally a summary of the grid impact indicators is given in the conclusion of this paper. © 2011 IEEE.

关键词： Smart power grids

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Comprehensive analysis of compositional interface fluctuations in planar lipid bilayer membranes

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Physical Review E 2011年第5期84卷 051903-051903页

作者： Tao Han Mikko Haataja Department of Mechanical and Aerospace Engineering Princeton Institute for the Science and Technology of Materials (PRISM) and Program in Applied and Computational Mathematics (PACM) Princeton University Princeton New Jersey 08544 USA

In this paper we present a comprehensive analysis of line tension-driven compositional interface fluctuations in planar lipid bilayer membranes. Our starting point is the advective Cahn-Hilliard equation for the local lipid composition in symmetric membranes, which explicitly incorporates both advective and diffusive lipid transport processes, and which is coupled to the continuum hydrodynamic equations governing the flow behavior of the membrane and surrounding solvent with finite subphase thickness. In order to extract the interface dynamics from the continuum phase-field formalism, we first derive the appropriate sharp-interface limit equations. We then carry out a linear perturbation analysis for the relaxational dynamics of small-amplitude sinusoidal interface fluctuations to yield the general dispersion relation ωk as a function of perturbation wave number k. The resulting expression incorporates the effects of diffusive and advective lipid transport processes within the membrane, viscous or viscoelastic membrane properties, coupling between membrane and solvent, and inertial effects within the membrane and solvent. It is shown that previously considered scenarios naturally emerge as limiting cases of the general result. Furthermore, we discuss two additional scenarios amenable to analysis, one in which the inertia of the solvent is relevant, and another one in which the membrane displays significant viscoelastic properties. Finally, we numerically evaluate the general dispersion relation for three representative model membrane systems.

关键词： BILAYER lipid membranes FLUCTUATIONS (physics) PERTURBATION (Mathematics) VISCOELASTICITY HYDRODYNAMICS

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Deformation Behavior of Material

Deformation Behavior of Material

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International Conference on Nanoscience, Technology and Societal Implications (NSTSI)

作者： S. K. Pradhan P. Kour Department of Mechanical Engineering Birla Institute of Technology Patna India Department of Applied Physics Birla Institute of Technology Patna India

The microstructure evolution of Aluminum was investigated in different temperature range. Then the effect of different microstructure on high temperature deformation behavior was further studied. With the aid of scanning electronic microscopy (SEM) the fractography of Aluminum after super plastic deformation was analyzed. The results reveal that intergranular cavities with fine size & homogeneous distribution are beneficial to super plastic deformation. For characterization of material we take material like aluminum. We prepared test specimen having length 32cm, diameter *** test specimen was installed in the UTM(40T) & loaded in tension. Load-displacement diagram has been plotted for the entire specimen. Then another three specimen each of aluminum have been prepared & they have been kept in the muffle furnace for 30 minutes for a temperature of 200 ,250,300,400 deg. Centigrade. Then the above specimen was installed in UTM & loaded in tension. Then load- displacement diagram have been plotted for above specimen with different temperature .Results were compared with variation of temperature. Then above characterization will be utilized in the various engg. application.

关键词： Cavity resonators Temperature Aluminum Strain Plastics Microstructure

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mechanical Properties of Al Thin Films as Measured by Bulge Testing

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MRS Online Proceedings Library 2011年第1期594卷 135-140页

作者： Yinmin Wang Richard L. Edwards Kevin J. Hemker Department of Materials Science and Engineering Johns Hopkins University Baltimore USA Applied Physics Laboratory Johns Hopkins University Baltimore USA Department of Mechanical Engineering Johns Hopkins University Baltimore USA

Free-standing rectangular Al thin films have been fabricated using sputter deposition and standard micromachining techniques. mechanical properties and residual stresses of both asdeposited and annealed Al films were measured by bulge testing. The films were loaded into the plastic deformation regime, and then unloaded and reloaded several times. The pressure and deflection of the thin films were recorded and used to generate stress-strain curves. The planestrain elastic modulus, flow stress and plastic behavior of the Al thin films were used to characterize the mechanical response of these films. The Al films were measured to have a plane-strain modulus that is slightly lower than the literature values for a {111} textured film. The Von-Mises equivalent yield stress was measured to be higher in the annealed films but much more significant strain hardening was observed in the as-deposited films. A plastic hysteresis was observed on unloading and reloading stress-strain curves of the as-deposited Al films but not the annealed films.

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The re-evaluation of mechanical properties of wire bonding

The re-evaluation of mechanical properties of wire bonding

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2011 International Symposium on Advanced Packaging Materials, APM 2011

作者： Jalar, Azman Zulkifli, Muhammad Nubli Othman, Norinsan Kamil Abdullah, Shahrum Universiti Kebangsaan Malaysia 43600 Bangi Selangor Malaysia School of Applied Physics Faculty of Science and Technology Universiti Kebangsaan Malaysia 43600 Bangi Selangor Malaysia Department of Mechanical and Materials Engineering Universiti Kebangsaan Malaysia 43600 Bangi Selangor Malaysia

ISBN: (纸本)9781467301473

Wire bonding is the most popular interconnection technique that has been used in microelectronics packaging due to its maturity and cost effectiveness. The technology advances in the era of miniaturization and multifunction have urges the need for the smaller wire bond size to cope with the decrease of bond pad pitches. Ultimately, this will introduces al lot of technology challenges in the characterization and performance of wire bonding micromechanical properties. The conventional tests such as wire pull and ball shear tests provide inadequate information in respect of bonding and metallurgical response of the interconnection. This is because the evaluations of wire bond performance based on conventional tests are more into qualitative results or failure modes rather than detailed quantitative results. Furthermore, the results obtained through wire pull and ball shear tests will change and introduce a lot of variations as the ball bond diameter become smaller. In the present analysis, nanoindentation test was introduced in order to provide more adequate information about the quality of wire bond. Nanoindentation test provides the micromechanical properties in terms of hardness and reduced modulus value in the small length scale. This will facilitate the micromechanical properties measurement of the wire bond. In addition, the continuous measurement of stiffness provided from nanoindentation test realizes the qualitative results of materials such as deformation, strain hardening effect and creep behaviour. Wire bonding process was prepared using thermosonic wire bonding technology using 25 μm diameter of gold wire on the Aluminium bond pad. The nanoindentation test was conducted at various locations on the ball bond that has been cross-sectioned diagonally prior to the indentation process. To further investigate the micromechanical properties, the location of indentations was divided into two zones namely Zone 1 and Zone 2. Zone 1 is located at the area near to the

关键词： Hardness

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Excimer-Laser-Induced Melting and Solidification of PECVD a-Si films under Partial-Melting Conditions

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MRS Online Proceedings Library (OPL) 2011年第1期1321卷 mrss11-1321-a06-10-mrss11-1321-a06-10页

作者： Q. Hu Catherine S. Lee T. Li Y. Deng U.J. Chung A. B. Limanov A. M. Chitu M.O. Thompson James S. Im Program in Materials Science and Engineering Department of Applied Physics and Applied Mathematics Columbia University New York NY USA Department of Materials Science and Engineering College of Engineering Korea Advanced Institute of Science and Technology Daejeon Korea Department of Materials Science and Engineering College of Engineering Cornell University Ithaca NY USA

This paper reports on new experimental findings and conclusions regarding the pulsed-laser-induced melting-and-solidification behavior of PECVD a-Si films. The experimental findings reveal that, within the partial-melting regime, these a-Si films can melt and solidify in ways that are distinct from, and more complex than, those encountered in microcrystalline-cluster-rich LPCVD a-Si films. Specifically (1) spatially dispersed and temporally stochastic nucleation of crystalline solids occurring relatively effectively at the moving liquid-amorphous interface, (2) very defective crystal growth that leads to the formation of fine-grained Si proceeding, at least initially after the nucleation, at a sufficiently rapidly moving crystal solidification front, and (3) the propensity for local preferential remelting of the defective regions and grain boundaries (while the beam is still on) are identified as being some of the fundamental factors that can participate and affect how these PECVD films melt and solidify.

关键词： crystalline laser annealing amorphous

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Squaraine donors for high efficiency small molecule solar cells

Squaraine donors for high efficiency small molecule solar ce...

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37th IEEE Photovoltaic Specialists Conference, PVSC 2011

作者： Wei, Guodan Wang, Siyi Xiao, Xin Renshaw, C. Kyle Hall, Lincoln Diev, Vyacheslav V. Thompson, Mark E. Forrest, Stephen R. Department of Materials Science and Engineering University of Michigan Ann Arbor MI United States Department of Chemistry University of Southern California Los Angeles CA United States Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI United States Applied Physics Program University of Michigan Ann Arbor MI United States Department of Physics University of Michigan Ann Arbor MI United States

ISBN: (纸本)9781424499656

It has been a challenge to achieve high efficiency organic photovoltaics (OPV) that absorb long wavelength solar radiation without incurring unacceptable reductions in open circuit voltage (Voc) or charge separation efficiency. Based on the parent structure of the 2, 4-bis[4-(N, N-diisobutylamino)-2,6-dihydroxyphenyl] squaraine (SQ), we have increased V oc using a family of highly near-infrared absorbing SQs, achieving values as high as 0.94 V. These SQ donors are: 2, 4-bis[4-(N-Phenyl-1- naphthylamino)-2,6-dihydroxyphenyl] squaraine (1-NPSQ),2,4-bis[4-(N, N-diphenylamino)-2,6 dihydroxyphenyl] squaraine (DPSQ), 2,4-bis[4-(N, N-diphenylamino)-2,6-dihydroxyphenyl] asymmetric squaraine (DPASQ). The spin-cast SQ, 1-NPSQ, DPSQ and DPASQ donors are then coated with the acceptor C60 to form bulk heterojunction (BHJ) solar cells that take advantage of their exceptionally high absorption coefficient and nanocrystalline morphology to overcome the short diffusion length characteristic of these materials. Combined with a high short-circuit current density (J sc=10.6 mA/cm2) and high fill factor (FF=0.64), the optimized 1-NPSQ/C60 photovoltaic cells with 1-NPSQ annealed at elevated temperature have a power conversion efficiency of ηp as high as 6.0% (correcting for solar mismatch) at 1 sun (AM 1.5G) simulated solar illumination, which to our knowledge is the highest efficiency reported to date for small molecule OPVs. © 2011 IEEE.

关键词： Solar cells

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