Now showing items 1-20 of 457

    • A diffusion-viscous analysis and experimental verification of defect formation in sintered silver bond-line 

      Xiao, K.; Ngo, K. D. T.; Lu, G. Q. (Cambridge University Press, 2014-04-01)
      The low-temperature joining technique (LTJT) by silver sintering is being implemented by major manufacturers of power electronic devices and modules for bonding power semiconductor chips. A common die-attach material used ...
    • A Framework for Occupancy Tracking in a Building via Structural Dynamics Sensing of Footstep Vibrations 

      Poston, Jeffrey D.; Buehrer, R. Michael; Tarazaga, Pablo A. (Frontiers, 2017-11-06)
      Counting the number of occupants in building areas over time—occupancy tracking— provides valuable information for responding to emergencies, optimizing thermal conditions or managing personnel. This capability is distinct ...
    • Aberrant Calcium Signaling in Astrocytes Inhibits Neuronal Excitability in a Human Down Syndrome Stem Cell Model 

      Mizuno, Grace O.; Wang, Yinxue; Shi, Guilai; Wang, Yizhi; Sun, Junqing; Papadopoulos, Stelios; Broussard, Gerard J.; Unger, Elizabeth K.; Deng, Wenbin; Weick, Jason; Bhattacharyya, Anita; Chen, Chao-Yin; Yu, Guoqiang; Looger, Loren L.; Tian, Lin (Elsevier, 2018-07-10)
      Down syndrome (DS) is a genetic disorder that causes cognitive impairment. The staggering effects associated with an extra copy of human chromosome 21 (HSA21) complicates mechanistic understanding of DS pathophysiology. ...
    • Acoustic X-wave reflection and transmission at a planar interface: Spectral analysis 

      Shaarawi, Amr M.; Besieris, Ioannis M.; Attiya, Ahmed M.; El-Diwany, Essam (Acoustical Society of America, 2000-01-01)
      The spectral structure of a three-dimensional X-wave pulse incident on a planar surface of discontinuity is examined. Introducing a novel superposition of azimuthally dependent pulsed plane waves, it is shown for oblique ...
    • Acousto-Optics: introduction to the feature issue 

      Poon, Ting-Chung; Tsai, C. S.; Voloshinov, V. B.; Chatterjee, M. R. (Optical Society of America, 2009-03-01)
      This Acousto-Optics feature celebrates the scientific careers of two remarkable scientists, Antoni Sliwinski and Adrian Korpel. The feature includes original papers based on a representative selection of topics that were ...
    • Active suppression of acoustic radiation from impulsively excited structures 

      Baumann, William T.; Saunders, William R.; Robertshaw, Harry H. (Acoustical Society of America, 1991-12-01)
      The objective is to use active control to suppress the acoustic energy that is radiated to the far field from a structure that has been excited by a short-duration pulse. The problem is constrained by the assumption that ...
    • Adaptive Optical Scanning Holography 

      Tsang, P. W. M.; Poon, Ting-Chung; Liu, J. -P. (Springer Nature, 2016-02-26)
      Optical Scanning Holography (OSH) is a powerful technique that employs a single-pixel sensor and a row-by-row scanning mechanism to capture the hologram of a wide-view, three-dimensional object. However, the time required ...
    • "Adaptive Pilot Patterns for CA-OFDM Systems in Non-stationary Wireless Channels" 

      Rao, Raghunandan M.; Marojevic, Vuk; Reed, Jeffrey H. (Institute Of Electrical And Electronics Engineers, 2017-09-12)
      Abstract -- In this paper, we investigate the performance gains of adapting pilot spacing and power for Carrier Aggregation (CA)-OFDM systems in nonstationary wireless channels. In current multi-band CAOFDM wireless networks, ...
    • Adhesive bondline interrogation using Stoneley wave methods 

      Claus, Richard O.; Kline, R. A. (American Institute of Physics, 1979)
      In this work, a new technique for analyzing interfacial conditions in completed adhesive bonds is discussed. This method is based on the sensitivity of Stoneley waves, which propagate along the boundary between dissimilar ...
    • Aging into Perceptual Control: A Dynamic Causal Modeling for fMRI Study of Bistable Perception 

      Ehsan Dowlati; Sarah E. Adams; Alexandra B. Stiles; Rosalyn J. Moran (Frontiers Media S.A., 2016-03-31)
      Aging is accompanied by stereotyped changes in functional brain activations, for example a cortical shift in activity patterns from posterior to anterior regions is one hallmark revealed by functional magnetic resonance ...
    • An Architecture for Electronic Textiles 

      Jones, Mark T.; Martin, Thomas L.; Sawyer, Braden (ICST, 2008)
      This paper makes a case for a communication architecture for electronic textiles (e-textiles). The properties and re- quirements of e-textile garments are described and analyzed. Based on these properties, the authors make ...
    • Analysis Of A High-Speed Fiber-Optic Spectrometer For Fiber-Optic Sensor Signal Processing 

      Wang, Y. X.; Han, M.; Wang, Anbo (Optical Society of America, 2007)
      A novel high-speed fiber-optic spectrometer has been demonstrated in our previous work. The high-speed spectrum measurement is enabled by translating the spectral-domain signal into a time-domain signal through a dispersion ...
    • Analysis of one-dimensional photonic band gap structures with a liquid crystal defect towards development of fiber-optic tunable wavelength filters 

      Del Villar, I.; Matias, I. R.; Arregui, F. J.; Claus, Richard O. (Optical Society of America, 2003-03-01)
      A theoretical analysis of a fiber optical photonic band gap based tunable wavelength filter is presented. The design presented here is based on the quarter wave reflector with a liquid crystal defect layer in the middle ...
    • Analysis of optical response of long period fiber gratings to nm-thick thin-film coatings 

      Wang, Z. Y.; Heflin, James R.; Stolen, R. H.; Ramachandran, S. (Optical Society of America, 2005-04-01)
      We have theoretically and experimentally demonstrated that the resonant wavelength of long period fiber gratings (LPG) can be shifted by a large magnitude by coating with only a nm-thickthin-film that has a refractive index ...
    • Analysis of ultrasonic frequency response of surface attached fiber Bragg grating 

      Li, Z. X.; Pei, L.; Dong, Bin; Ma, C.; Wang, Anbo (Optical Society of America, 2012-07-01)
      In recent years, fiber Bragg grating (FBG), for the well-known advantages over other fiber optic sensors, has attracted more attention in ultrasonic inspection for structure health monitoring (SHM). Spectrum shift of FBG ...
    • Analytical brightness compensation algorithm for traditional polygon-based method in computer-generated holography 

      Pan, Y. J.; Wang, Y. T.; Liu, J.; Li, X.; Jia, J.; Zhang, Z. (Optical Society of America, 2013-06-01)
      In three-dimensional (3D) holographic display, current brightness compensation algorithm of the traditional polygon-based method experimentally obtains the compensation factor, which depends on the fabrication process. In ...
    • Anomalously low geomagnetic energy inputs during 2008 solar minimum 

      Deng, Yue; Huang, Yanshi; Solomon, Stan; Qian, Liying; Knipp, Delores; Weimer, Daniel R.; Wang, Jing-Song (American Geophysical Union, 2012-09-01)
      The record-low thermospheric density during the last solar minimum has been reported and it has been mainly explained as the consequence of the anomalously low solar extreme ultraviolet (EUV) irradiance. In this study, we ...
    • Anti-islanding detection for three-phase distributed generation 

      Virginia Tech Intellectual Properties, Inc.; Dong, Dong; Boroyevich, Dushan; Mattavelli, Paolo (United States Patent and Trademark Office, 2017-04-25)
      Wobbling the operating frequency of a phase-locked loop (PLL), preferably by adding a periodic variation is feedback gain or delay in reference signal phase allows the avoidance of any non-detection zone that might occur ...
    • Aperture synthesis of time-limited X waves and analysis of their propagation characteristics 

      Chatzipetros, Argyrios A.; Shaarawi, Amr M.; Besieris, Ioannis M.; Abdel-Rahman, Mohamed A. (Acoustical Society of America, 1998-05-01)
      The feasibility of exciting a localized X-wave pulse from a finite aperture is addressed. Also, the possibility of using a finite-time excitation of a dynamic aperture to generate a finite-energy approximation to an X-wave ...
    • Application of Cybernetics and Control Theory for a New Paradigm in Cybersecurity 

      Adams, Michael D.; Hitefield, Seth D.; Hoy, Bruce; Fowler, Michael C.; Clancy, T. Charles (Virginia Tech, 2013-11-01)
      A significant limitation of current cyber security research and techniques is its reactive and applied nature. This leads to a continuous ‘cyber cycle’ of attackers scanning networks, developing exploits and attacking ...