7,081 research outputs found

    The polar temperature of Venus

    Get PDF
    Interferometric and polarization measurements of polar regions of Venu

    Laser communication system for controlling several functions at a location remote to the laser

    Get PDF
    A multichannel laser remote control system is described. The system is used in areas where radio frequency, acoustic, and hardware control systems are unsatisfactory or prohibited and where line of sight is unobstructed. A modulated continuous wave helium-neon laser is used as the transmitter and a 360 degree light collector serves as the antenna at the receiver

    Patent Institutions: Shifting Interactions Between Legal Actors

    Get PDF
    This contribution to the Research Handbook on Economics of Intellectual Property Rights (Vol. 1 Theory) addresses interactions between the principal legal institutions of the U.S. patent system. It considers legal, strategic, and normative perspectives on these interactions as they have evolved over the last 35 years. Early centralization of power by the U.S. Court of Appeals for the Federal Circuit, newly created in 1982, established a regime dominated by the appellate court\u27s bright-line rules. More recently, aggressive Supreme Court and Congressional intervention have respectively reinvigorated patent law standards and led to significant devolution of power to inferior tribunals, including newly created tribunals like the USPTO\u27s Patent Trial and Appeals Board. This new era in institutional interaction creates a host of fresh empirical and normative research questions for scholars. The contribution concludes by outlining a research agenda

    Electrical properties of breast cancer cells from impedance measurement of cell suspensions

    Get PDF
    Impedance spectroscopy of biological cells has been used to monitor cell status, e.g. cell proliferation, viability, etc. It is also a fundamental method for the study of the electrical properties of cells which has been utilised for cell identification in investigations of cell behaviour in the presence of an applied electric field, e.g. electroporation. There are two standard methods for impedance measurement on cells. The use of microelectrodes for single cell impedance measurement is one method to realise the measurement, but the variations between individual cells introduce significant measurement errors. Another method to measure electrical properties is by the measurement of cell suspensions, i.e. a group of cells within a culture medium or buffer. This paper presents an investigation of the impedance of normal and cancerous breast cells in suspension using the Maxwell-Wagner mixture theory to analyse the results and extract the electrical parameters of a single cell. The results show that normal and different stages of cancer breast cells can be distinguished by the conductivity presented by each cell. © 2010 IOP Publishing Ltd

    Delineation of Emitter-Collector Shorts in Bipolar Test Structures by Voltage Contrast Scanning Electron Microscopy

    Get PDF
    In examining emitter-collector shorts and their relationship to structural defects, we desire a nondestructive method for locating the short-circuited devices in large test arrays. Voltage contrast scanning electron microscopy (VC-SEM) and an established electrochemical anodization technique have been used to identify electrically faulty bipolar transistors. Direct comparison of these approaches was achieved by examining the same emitters with each method. The results indicate that VC-SEM may serve as a useful technique for delineating E-C shorts because of its nondestructive and purely electrical nature. In our qualitative investigation, the sensitivity and voltage resolution available by VC-SEM were not sufficient to differentiate device leakage levels as is often possible with anodization. Such information may, however, be obtainable by utilizing image subtraction and more sophisticated detector systems. Transmission electron microscopy of the transistor structures revealed dislocations in many short-circuited emitters and occasionally in unshorted devices. This confirmed prior observations that crystallographic defects in silicon devices may sometimes be, but are not always, electrically active. Deleterious effects may depend on factors such as junction penetration and dopant-defect interactions

    Genetic Connectivity in Scleractinian Corals across the Northern Gulf of Mexico: Oil/Gas Platforms, and Relationship to the Flower Garden Banks

    Get PDF
    The 3,000 oil/gas structures currently deployed in the northern Gulf of Mexico (GOM) provide hard substratum for marine organisms in a region where such has been rare since the Holocene. The major exception to this are the Flower Garden Banks (FGB). Corals are known to have colonized oil/gas platforms around the FGB, facilitating biogeographic expansion. We ask the question, what are the patterns of genetic affinity in these coral populations. We sampled coral tissue from populations of two species occurring on oil and gas platforms: Madracis decactis (hermatype) and Tubastraea coccinea (invasive ahermatype). We sampled 28 platforms along four transects from 20 km offshore to the continental shelf edge off 1) Matagorda Island, TX; 2) Lake Sabine, TX; 3) Terrebonne Bay, LA; and 4) Mobile, AL. The entire population of M. decactis was sampled between depths of 5 m and 37 m. T. coccinea populations were sub-sampled. Genetic variation was assessed using the PCR-based Amplified Fragment Length Polymorphisms (AFLPs). Data were analyzed via AFLPOP and STRUCTURE. Genetic connectivity among M. decactis platform populations was highest near the FGB and decreased to the east. Connectivity increased again in the eastern sector, indicating isolation between the populations from different sides of the Mississippi River (Transects 3 and 4). A point-drop in genetic affinity (relatedness) at the shelf edge south of Terrebonne Bay, LA indicated a population differing from all others in the northern GOM. Genetic affinities among T. coccinea were highest in the west and decreased to the east. Very low genetic affinities off Mobile, AL indicated a dramatic difference between those populations and those west of the Mississippi River, apparently a formidable barrier to larval dispersal

    Quantum Memory with a controlled homogeneous splitting

    Full text link
    We propose a quantum memory protocol where a input light field can be stored onto and released from a single ground state atomic ensemble by controlling dynamically the strength of an external static and homogeneous field. The technique relies on the adiabatic following of a polaritonic excitation onto a state for which the forward collective radiative emission is forbidden. The resemblance with the archetypal Electromagnetically-Induced-Transparency (EIT) is only formal because no ground state coherence based slow-light propagation is considered here. As compared to the other grand category of protocols derived from the photon-echo technique, our approach only involves a homogeneous static field. We discuss two physical situations where the effect can be observed, and show that in the limit where the excited state lifetime is longer than the storage time, the protocols are perfectly efficient and noise-free. We compare the technique to other quantum memories, and propose atomic systems where the experiment can be realized.Comment: submitted to New Journal of Physics, Focus on Quantum Memor

    Mid-infrared quantum optics in silicon

    Full text link
    Applied quantum optics stands to revolutionise many aspects of information technology, provided performance can be maintained when scaled up. Silicon quantum photonics satisfies the scaling requirements of miniaturisation and manufacturability, but at 1.55 μ\mum it suffers from unacceptable linear and nonlinear loss. Here we show that, by translating silicon quantum photonics to the mid-infrared, a new quantum optics platform is created which can simultaneously maximise manufacturability and miniaturisation, while minimising loss. We demonstrate the necessary platform components: photon-pair generation, single-photon detection, and high-visibility quantum interference, all at wavelengths beyond 2 μ\mum. Across various regimes, we observe a maximum net coincidence rate of 448 ±\pm 12 Hz, a coincidence-to-accidental ratio of 25.7 ±\pm 1.1, and, a net two photon quantum interference visibility of 0.993 ±\pm 0.017. Mid-infrared silicon quantum photonics will bring new quantum applications within reach.Comment: 8 pages, 4 figures; revised figures, updated discussion in section 3, typos corrected, added referenc
    corecore