WorldWideScience

Sample records for atmospheric interference

  1. Interferences of commercial NO2 instruments in the urban atmosphere and in a smog chamber

    Directory of Open Access Journals (Sweden)

    J. Kleffmann

    2012-01-01

    Full Text Available Reliable measurements of atmospheric trace gases are necessary for both, a better understanding of the chemical processes occurring in the atmosphere, and for the validation of model predictions. Nitrogen dioxide (NO2 is a toxic gas and is thus a regulated air pollutant. Besides, it is of major importance for the oxidation capacity of the atmosphere and plays a pivotal role in the formation of ozone and acid precipitation. Detection of NO2 is a difficult task since many of the different commercial techniques used are affected by interferences. The chemiluminescence instruments that are used for indirect NO2 detection in monitoring networks and smog chambers use either molybdenum or photolytic converters and are affected by either positive (NOy or negative interferences (radical formation in the photolytic converter. Erroneous conclusions on NO2 can be drawn if these interferences are not taken into consideration. In the present study, NO2 measurements in the urban atmosphere, in a road traffic tunnel and in a smog-chamber using different commercial techniques, i.e. chemiluminescence instruments with molybdenum or photolytic converters, a Luminol based instrument and a new NO2-LOPAP, were compared with spectroscopic techniques, i.e. DOAS and FTIR. Interferences of the different instruments observed during atmospheric measurements were partly characterised in more detail in the smog chamber experiments. Whereas all the commercial instruments showed strong interferences, excellent agreement was obtained between a new NO2-LOPAP instrument and the FTIR technique for the measurements performed in the smog chamber.

  2. Autofluorescence of atmospheric bioaerosols – fluorescent biomolecules and potential interferences

    Directory of Open Access Journals (Sweden)

    C. Pöhlker

    2012-01-01

    Full Text Available Primary biological aerosol particles (PBAP are an important subset of air particulate matter with a substantial contribution to the organic aerosol fraction and potentially strong effects on public health and climate. Recent progress has been made in PBAP quantification by utilizing real-time bioaerosol detectors based on the principle that specific organic molecules of biological origin such as proteins, coenzymes, cell wall compounds and pigments exhibit intrinsic fluorescence. The properties of many fluorophores have been well documented, but it is unclear which are most relevant for detection of atmospheric PBAP. The present study provides a systematic synthesis of literature data on potentially relevant biological fluorophores. We analyze and discuss their relative importance for the detection of fluorescent biological aerosol particles (FBAP by online instrumentation for atmospheric measurements such as the ultraviolet aerodynamic particle sizer (UV-APS or the wide issue bioaerosol sensor (WIBS.

    In addition, we provide new laboratory measurement data for selected compounds using bench-top fluorescence spectroscopy. Relevant biological materials were chosen for comparison with existing literature data and to fill in gaps of understanding. The excitation-emission matrices (EEM exhibit pronounced peaks at excitation wavelengths of ~280 nm and ~360 nm, confirming the suitability of light sources used for online detection of FBAP. They also show, however, that valuable information is missed by instruments that do not record full emission spectra at multiple wavelengths of excitation, and co-occurrence of multiple fluorophores within a detected sample will likely confound detailed molecular analysis. Selected non-biological materials were also analyzed to assess their possible influence on FBAP detection and generally exhibit only low levels of background-corrected fluorescent emission. This study strengthens the hypothesis that ambient

  3. Autofluorescence of atmospheric bioaerosols – fluorescent biomolecules and potential interferences

    Directory of Open Access Journals (Sweden)

    C. Pöhlker

    2011-09-01

    Full Text Available Primary biological aerosol particles (PBAP are an important subset of air particulate matter with a substantial contribution to the organic aerosol fraction and potentially strong effects on public health and climate. Recent progress has been made in PBAP quantification by utilizing real-time bioaerosol detectors based on the principle that specific organic molecules of biological origin such as proteins, coenzymes, cell wall compounds and pigments exhibit intrinsic fluorescence. The properties of many fluorophores have been well documented, but it is unclear which are most relevant for detection of atmospheric PBAP. The present study provides a systematic synthesis of literature data on potentially relevant biological fluorophores. We analyze and discuss their relative importance for the detection of fluorescent biological aerosol particles (FBAP by online instrumentation for atmospheric measurements such as the ultraviolet aerodynamic particle sizer (UV-APS or the wide issue bioaerosol sensor (WIBS.

    In addition, we provide new laboratory measurement data for selected compounds using bench-top fluorescence spectroscopy. Relevant biological materials were chosen for comparison with existing literature data and to fill in gaps of understanding. The excitation-emission matrices (EEM exhibit pronounced peaks at excitation wavelengths of ~280 nm and ~360 nm, confirming the suitability of light sources used for online detection of FBAP. They also show, however, that valuable information is missed by instruments that do not record full emission spectra at multiple wavelengths of excitation, and co-occurrence of multiple fluorophores within a detected sample will likely confound detailed molecular analysis. Selected non-biological materials were also analyzed to assess their possible influence on FBAP detection and generally exhibit only low levels of background-corrected fluorescent emission. This study strengthens the hypothesis that ambient

  4. Technical Note: Interference errors in infrared remote sounding of the atmosphere

    Directory of Open Access Journals (Sweden)

    R. Sussmann

    2007-07-01

    Full Text Available Classical error analysis in remote sounding distinguishes between four classes: "smoothing errors," "model parameter errors," "forward model errors," and "retrieval noise errors". For infrared sounding "interference errors", which, in general, cannot be described by these four terms, can be significant. Interference errors originate from spectral residuals due to "interfering species" whose spectral features overlap with the signatures of the target species. A general method for quantification of interference errors is presented, which covers all possible algorithmic implementations, i.e., fine-grid retrievals of the interfering species or coarse-grid retrievals, and cases where the interfering species are not retrieved. In classical retrieval setups interference errors can exceed smoothing errors and can vary by orders of magnitude due to state dependency. An optimum strategy is suggested which practically eliminates interference errors by systematically minimizing the regularization strength applied to joint profile retrieval of the interfering species. This leads to an interfering-species selective deweighting of the retrieval. Details of microwindow selection are no longer critical for this optimum retrieval and widened microwindows even lead to reduced overall (smoothing and interference errors. Since computational power will increase, more and more operational algorithms will be able to utilize this optimum strategy in the future. The findings of this paper can be applied to soundings of all infrared-active atmospheric species, which include more than two dozen different gases relevant to climate and ozone. This holds for all kinds of infrared remote sounding systems, i.e., retrievals from ground-based, balloon-borne, airborne, or satellite spectroradiometers.

  5. Dependence of level of radio interference from insulators on atmospheric conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yen Dar; Tarasova, N.F.

    1985-08-01

    Radio interference is becoming an increasingly important factor in selection and design of insulators for overhead transmission lines, inasmuch as the trend toward superhigh voltages carries with it problems of ionization and high-frequency currents. Extensive experimental studies made in the high-voltage laboratory at the Special Design and Manufacturing Engineering Office of Soyuzelektrosetizolatsiya over a period of two years have yielded a wealth of data on radio interference from insulators under various atmospheric conditions. While the air temperature was varied over the 13-35/sup 0/C range and the air pressure was varied over the 742-761 mm Hg range, the relative humidity was varied from 30% to 80%. Along with PSG 120 and PS 160-V glass dish insulators were also tested model glass disks 200 mm in diameter and 10+/-2 mm thick between a high-voltage electrode 12 mm in diameter at the contact with glass and a ground electrode 70 mm in diameter. The level of radio interference was found to depend strongly on the relative air humidity. Analysis and interpretation of the data in terms of the fundamental relation between high-frequency current and mtmum electric field intensity indicates that this relation is influenced by tric material depends on the latter. Theory thus confirms the evidence that the interference level drops with rising relative air humidity, probably because the electrical surface resistivity of the dielectric material then decreases and this tends to reduce the uniformity of the electric field along the insulator.

  6. Vacillations due to wave interference - Applications to the atmosphere and to annulus experiments

    Science.gov (United States)

    Lindzen, R. S.; Farrell, B.; Jacqmin, D.

    1982-01-01

    It is noted that vacillations in zonally averaged flows can arise from wave interference between coexisting waves with the same zonal wavenumber but different phase speeds. It is shown that the appropriate baroclinic instability problem for the annulus does yield multiple instabilities which can produce vacillations via interference. It is also shown that the interference of traveling Rossby waves with stationary forced waves can lead to vacillations whose amplitudes and periods are consistent with the observed index cycle.

  7. Effect of atmospheric interference and sensor noise in retrieval of optically active materials in the ocean by hyperspectral remote sensing.

    Science.gov (United States)

    Levin, Iosif M; Levina, Elizaveta

    2007-10-01

    We present a method to construct the best linear estimate of optically active material concentration from ocean radiance spectra measured through an arbitrary atmosphere layer by a hyperspectral sensor. The algorithm accounts for sensor noise. Optical models of seawater and maritime atmosphere were used to obtain the joint distribution of spectra and concentrations required for the algorithm. The accuracy of phytoplankton retrieval is shown to be substantially lower than that of sediment and dissolved matter. In all cases, the sensor noise noticeably reduces the retrieval accuracy. Additional errors due to atmospheric interference are analyzed, and possible ways to increase the accuracy of retrieval are suggested, such as changing sensor parameters and including a priori information about observation conditions.

  8. Interferences of commercial NO2 instruments in the urban atmosphere and in a smog chamber

    OpenAIRE

    G. Villena; I. Bejan; R. Kurtenbach; P. Wiesen; Kleffmann, J.

    2012-01-01

    Reliable measurements of atmospheric trace gases are necessary for both, a better understanding of the chemical processes occurring in the atmosphere, and for the validation of model predictions. Nitrogen dioxide (NO2) is a toxic gas and is thus a regulated air pollutant. Besides, it is of major importance for the oxidation capacity of the atmosphere and plays a pivotal role in the formation of ozone and acid precipitation. Detection of NO2 is a difficult task since many of the different comm...

  9. Investigation of potential interferences in the detection of atmospheric ROx radicals by laser-induced fluorescence under dark conditions

    Science.gov (United States)

    Fuchs, Hendrik; Tan, Zhaofeng; Hofzumahaus, Andreas; Broch, Sebastian; Dorn, Hans-Peter; Holland, Frank; Künstler, Christopher; Gomm, Sebastian; Rohrer, Franz; Schrade, Stephanie; Tillmann, Ralf; Wahner, Andreas

    2016-04-01

    Direct detection of highly reactive, atmospheric hydroxyl radicals (OH) is widely accomplished by laser-induced fluorescence (LIF) instruments. The technique is also suitable for the indirect measurement of HO2 and RO2 peroxy radicals by chemical conversion to OH. It requires sampling of ambient air into a low-pressure cell, where OH fluorescence is detected after excitation by 308 nm laser radiation. Although the residence time of air inside the fluorescence cell is typically only on the order of milliseconds, there is potential that additional OH is internally produced, which would artificially increase the measured OH concentration. Here, we present experimental studies investigating potential interferences in the detection of OH and peroxy radicals for the LIF instruments of Forschungszentrum Jülich for nighttime conditions. For laboratory experiments, the inlet of the instrument was over flowed by excess synthetic air containing one or more reactants. In order to distinguish between OH produced by reactions upstream of the inlet and artificial signals produced inside the instrument, a chemical titration for OH was applied. Additional experiments were performed in the simulation chamber SAPHIR where simultaneous measurements by an open-path differential optical absorption spectrometer (DOAS) served as reference for OH to quantify potential artifacts in the LIF instrument. Experiments included the investigation of potential interferences related to the nitrate radical (NO3, N2O5), related to the ozonolysis of alkenes (ethene, propene, 1-butene, 2,3-dimethyl-2-butene, α-pinene, limonene, isoprene), and the laser photolysis of acetone. Experiments studying the laser photolysis of acetone yield OH signals in the fluorescence cell, which are equivalent to 0.05 × 106 cm-3 OH for a mixing ratio of 5 ppbv acetone. Under most atmospheric conditions, this interference is negligible. No significant interferences were found for atmospheric concentrations of reactants

  10. Characterization of typical chemical background interferences in atmospheric pressure ionization liquid chromatography-mass spectrometry

    NARCIS (Netherlands)

    Guo, Xinghua; Bruins, Andries P.; Covey, Thomas R.

    2006-01-01

    The structures and origins of typical chemical background noise ions in positive atmospheric pressure ionization liquid chromatography/mass spectrometry (API LC/MS) are investigated and summarized in this study. This was done by classifying chemical background ions using precursor and product ion sc

  11. Autofluorescence of atmospheric bioaerosols - fluorescent biomolecules, biological standard particles and potential interferences

    Science.gov (United States)

    Pöhlker, C.; Huffmann, J. A.; Pöschl, U.

    2012-04-01

    Primary biological aerosol particles (PBAP) such as pollen, fungal spores, bacteria, biogenic polymers and debris from larger organisms are known to influence atmospheric chemistry and physics, the biosphere and public health. PBAP account for up to ~30% of fine and up to ~70% of coarse particulate matter in urban, rural and pristine environment and are released with estimated emission rates of up to ~1000 Tg/a [1]. Continuous measurements of the abundance, variability and diversity of PBAP have been difficult until recently, however. The application of on-line instruments able to detect autofluorescence from biological particles in real-time has been a promising development for the measurement of PBAP concentrations and fluxes in different environments [2,3]. The detected fluorescent biological aerosol particles (FBAP) can be regarded as a subset of PBAP, although the exact relationship between PBAP and FBAP is still being investigated. Autofluorescence of FBAP is usually a superposition of fluorescence from a mixture of individual fluorescent molecules (fluorophores). Numerous biogenic fluorophores such as amino acids (e.g., tryptophan, tyrosine), coenzymes (e.g., NAD(P)H, riboflavin) and biopolymers (e.g., cellulose) emit fluorescent light due to heterocyclic aromatic rings or conjugated double bonds within their molecular structures. The tryptophan emission peak is a common feature of most bioparticles because the amino acid is a constituent of many proteins and peptides. The influence of the coenzymes NAD(P)H and riboflavin on the autofluorescence of bacteria can be regarded as an indicator for bacterial metabolism and has been utilized to discriminate between viable and non-viable organisms [4]. However, very little information is available about other essential biofluorophores in fungal spores and pollen. In order to better understand the autofluorescence behavior of FBAP, we have used fluorescence spectroscopy and fluorescence microscopy to analyze standard

  12. On the interference of 86Kr2+ during carbon isotope analysis of atmospheric methane using continuous flow combustion – isotope ratio mass spectrometry

    Directory of Open Access Journals (Sweden)

    T. Röckmann

    2013-02-01

    Full Text Available Stable carbon isotope analysis of methane (δ13C of CH4 on atmospheric samples is one key method to constrain the current and past atmospheric CH4 budget. A frequently applied measurement technique is gas chromatography isotope ratio mass spectrometry coupled to a combustion-preconcentration unit. This report shows that the atmospheric trace gas krypton can severely interfere during the mass spectrometric measurement leading to significant biases in δ13C of CH4 if krypton is not sufficiently separated during the analysis. The effect comes about by the lateral tailing of the peak of doubly charged 86Kr in the neighbouring m/z, 44, 45, and 46 Faraday cups. Accordingly, the introduced bias is dependent on the chromatographic separation, the Kr to CH4 mixing ratio in the sample, the mass spectrometer source tuning as well as the detector configuration and can amount to up to several permil in δ13C. Apart from technical solutions to avoid this interference we present correction routines to a posteriori remove the bias.

  13. High concentrations of N2O5 and NO3 observed in daytime with a TD-CIMS: chemical interference or a real atmospheric phenomenon?

    Directory of Open Access Journals (Sweden)

    X. Wang

    2013-08-01

    Full Text Available Dinitrogen pentoxide (N2O5 and the nitrate radical (NO3 play important roles in atmospheric chemistry, yet accurate measurements of their concentrations remain challenging. A thermal dissociation chemical ionization mass spectrometer (TD-CIMS was deployed to an urban site in Hong Kong to measure the sum of N2O5 and NO3 in autumn 2010. To our surprise, very high concentrations of N2O5 + NO3 were frequently observed in daytime, with mixing ratios in the range of 200–1000 pptv. To investigate this unusual phenomenon, various interference tests and measurements with different instrument configuration were conducted. It was found that peroxy acetyl nitrate (PAN contributed to measurable signals at 62 amu, and more importantly, this interference increased significantly with co-existence of NO2. Nitric acid (HNO3, on the other hand, had little interference to the detection of N2O5/NO3 via the NO3− ion in our TD-CIMS. According to the test results, the interference from PAN and NO2 could have contributed to 30–50% of the average daytime (12:00–16:00 LT N2O5 + NO3 signal at our site. However, evidence exists for the presence of elevated daytime N2O5, in addition to the daytime signal at 62 amu. This includes: (1 daytime N2O5 measured via the I(N2O5− cluster ion with an unheated inlet, which subjects to minimum interferences, and (2 observation of elevated daytime ClNO2 (a product of N2O5 hydrolysis during a follow-up study. In view of the difficulty in accurately quantifying the contribution from the interferences of PAN and NO2 and un-tested potential interfering chemicals in the real atmosphere, we caution the use of 62 amu in the TD-CIMS for measuring ambient N2O5 in a high NOx environment like Hong Kong. Additional studies are needed to re-examine the daytime issue using other measurement techniques.

  14. A comparison of the effectiveness of 6S and SMAC in correcting for atmospheric interference of meteosat second generation images

    DEFF Research Database (Denmark)

    Proud, Simon Richard; Fensholt, R.; Rasmussen, M.O.;

    2010-01-01

    Atmospheric perturbations are a large source of uncertainty in remotely sensed imagery of the Earth's surface. This paper explores the effectiveness of the simplified method for atmospheric correction (SMAC) in reducing the effects of these perturbations in images of the African Continent gathered......-to-high solar or viewing zenith angles (greater than 40°) or in areas with a high ozone or water vapor content (greater than 0.2 cm/atm and 1.5 gm/cm for ozone and water vapor respectively) returning a particularly high relative error. Nevertheless, as the SMAC is up to 3000 times faster in processing a SEVIRI...

  15. Atmospheric temperature profiling in the presence of clouds with a pure rotational Raman lidar by use of an interference-filter-based polychromator.

    Science.gov (United States)

    Behrendt, A; Reichardt, J

    2000-03-20

    A lidar polychromator design for the measurement of atmospheric temperature profiles in the presence of clouds with the rotational Raman method is presented. The design utilizes multicavity interference filters mounted sequentially at small angles of incidence. Characteristics of this design are high signal efficiency and adjustable center wavelengths of the filters combined with a stable and relatively simple experimental setup. High suppression of the elastic backscatter signal in the rotational Raman detection channels allows temperature measurements independent of the presence of thin clouds or aerosol layers; no influence of particle scattering on the lidar temperature profile was observed in clouds with a backscatter ratio of at least 45. The minimum integration time needed for temperature profiling with a statistical temperature error of +/-1 K at, e.g., 20-km height and 960-m height resolution is 1.5 h.

  16. 大气湍流畸变对空间目标清晰干涉成像仿真研究%Simulation for space target interference imaging system distorted by atmospheric turbulence

    Institute of Scientific and Technical Information of China (English)

    刘扬阳; 吕群波; 张文喜

    2012-01-01

    Interference imaging system for space target has close relation with atmospheric environment, and atmospheric turbulence disturbance distorts terribly the wavefront phase of any transmission optics launched from any optics system. In the space target interference imaging system the phase-closure-principle is adopted, in order to eliminate possible effects of atmospheric turbulence on the target image. Based on the power spectrum method and the Fourier transform method, the numerical simulation of wavefront phase screen, which is distorted by atmospheric turbulence conforming to the statistical rules of kolmogonov model and modified Von Karmen model, is respectively implemented. Various images by several different phase-screen models on the interference imaging system are obtained. Simulation results show that, with the advantage of adopting phase-closure-principle, the possible effects of atmospheric turbulence imaging can be eliminated basically.%本文利用功率谱反演法分别展开对符合Kolmogonov统计规律和修正后的VonKarmen统计规律的大气湍流畸变波前相位屏进行了数值模拟研究.得到各种模型下相位屏对该成像系统干涉成像图.仿真结果表明,采用闭合相位原理,基本可以消除大气湍流对光束波前的影响,验证了采用相位闭合技术的优势.

  17. Method to reduce chemical background interference in atmospheric pressure ionization liquid chromatography-mass spectrometry using exclusive reactions with the chemical reagent dimethyl disulfide

    NARCIS (Netherlands)

    Guo, Xinghua; Bruins, Andries P.; Covey, Thomas R.

    2007-01-01

    The interference of chemical background ions (chemical noise) has been a problem since the inception of mass spectrometry. We present here a novel method to reduce the chemical noise in LC-MS based on exclusive gas-phase reactions with a reactive collision gas in a triple-quadrupole mass spectromete

  18. Method to reduce chemical background interference in atmospheric pressure ionization liquid chromatography-mass spectrometry using exclusive reactions with the chemical reagent dimethyl disulfide.

    Science.gov (United States)

    Guo, Xinghua; Bruins, Andries P; Covey, Thomas R

    2007-06-01

    The interference of chemical background ions (chemical noise) has been a problem since the inception of mass spectrometry. We present here a novel method to reduce the chemical noise in LC-MS based on exclusive gas-phase reactions with a reactive collision gas in a triple-quadrupole mass spectrometer. Combined with the zero neutral loss (ZNL) scan of a triple-quadrupole mass spectrometer, the reactive chemical noise ions can be removed because of shifts of mass-to-charge ratios from the original background ions. The test on various classes of compounds with different functional groups indicates a generic application of this technique in LC-MS. The preliminary results show that a reduction of the level of LC-MS base-peak chromatographic baseline by a factor up to 40 and an improvement of the signal-to-noise ratio by a factor up to 5-10 are achieved on both commercial and custom-modified triple-quadrupole LC-MS systems. Application is foreseen in both quantitative and qualitative trace analysis. It is expected that this chemical noise reduction technique can be optimized on a dedicated mass spectrometric instrumentation which incorporates both a chemical reaction cell for noise reduction and a collision stage for fragmentation.

  19. Blind Known Interference Cancellation

    CERN Document Server

    Zhang, Shengli; Wang, Hui

    2011-01-01

    This paper investigates interference-cancellation schemes at the receiver, in which the original data of the interference is known a priori. Such a priori knowledge is common in wireless relay networks. For example, a transmitting relay could be relaying data that was previously transmitted by a node, in which case the interference received by the node now is actually self information. Besides the case of self information, the node could also have overheard or received the interference data in a prior transmission by another node. Directly removing the known interference requires accurate estimate of the interference channel, which may be difficult in many situations. In this paper, we propose a novel scheme, Blind Known Interference Cancellation (BKIC), to cancel known interference without interference channel information. BKIC consists of two steps. The first step combines adjacent symbols to cancel the interference, exploiting the fact that the channel coefficients are almost the same between successive sy...

  20. IETS and quantum interference

    DEFF Research Database (Denmark)

    Jørgensen, Jacob Lykkebo; Gagliardi, Alessio; Pecchia, Alessandro;

    2014-01-01

    Destructive quantum interference in single molecule electronics is an intriguing phenomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference effects in the transmission lead to either low...... suppressed when quantum interference effects dominate. That is, we expand the understanding of propensity rules in inelastic electron tunneling spectroscopy to molecules with destructive quantum interference....

  1. Communication and interference coordination

    OpenAIRE

    Blasco-Serrano, Ricardo; Thobaben, Ragnar; Skoglund, Mikael

    2014-01-01

    We study the problem of controlling the interference created to an external observer by a communication processes. We model the interference in terms of its type (empirical distribution), and we analyze the consequences of placing constraints on the admissible type. Considering a single interfering link, we characterize the communication-interference capacity region. Then, we look at a scenario where the interference is jointly created by two users allowed to coordinate their actions prior to...

  2. Dark Matter Interference

    DEFF Research Database (Denmark)

    Del Nobile, Eugenio; Kouvaris, Christoforos; Sannino, Francesco;

    2012-01-01

    We study different patterns of interference in WIMP-nuclei elastic scattering that can accommodate the DAMA and CoGeNT experiments via an isospin violating ratio $f_n/f_p=-0.71$. We study interference between the following pairs of mediators: Z and Z', Z' and Higgs, and two Higgs fields. We show ...

  3. How does interference fall?

    CERN Document Server

    Orlando, Patrick J; Modi, Kavan

    2016-01-01

    We study how single- and double-slit interference patterns fall in the presence of gravity. First, we demonstrate that universality of free fall still holds in this case, i.e., interference patterns fall just like classical objects. Next, we explore lowest order relativistic effects in the Newtonian regime by employing a recent quantum formalism which treats mass as an operator. This leads to interactions between non-degenerate internal degrees of freedom (like spin in an external magnetic field) and external degrees of freedom (like position). Based on these effects, we present an unusual phenomenon, in which a falling double slit interference pattern periodically decoheres and recoheres. The oscillations in the visibility of this interference occur due to correlations built up between spin and position. Finally, we connect the interference visibility revivals with non-Markovian quantum dynamics.

  4. Real Interference Alignment

    CERN Document Server

    Motahari, Abolfazl Seyed; Maddah-Ali, Mohammad-Ali; Khandani, Amir Keyvan

    2010-01-01

    In this paper, we show that the total Degrees-Of-Freedoms (DOF) of the $K$-user Gaussian Interference Channel (GIC) can be achieved by incorporating a new alignment technique known as \\emph{real interference alignment}. This technique compared to its ancestor \\emph{vector interference alignment} performs on a single real line and exploits the properties of real numbers to provide optimal signaling. The real interference alignment relies on a new coding scheme in which several data streams having fractional multiplexing gains are sent by transmitters and interfering streams are aligned at receivers. The coding scheme is backed up by a recent result in the field of Diophantine approximation, which states that the convergence part of the Khintchine-Groshev theorem holds for points on non-degenerate manifolds.

  5. Interference nature of light

    Institute of Scientific and Technical Information of China (English)

    Yao Zhi-Xin; Zhong Jian-Wei; Mao Bang-Ning; Pan Bai-Liang

    2008-01-01

    Interference of light has been reinvestigated theoretically by linear superposition of two different state-vector functions,of which each describes the photons from one of two different light sources in both polarization and intensity.By the use of microscopic parameters for a photon,namely probability amplitude and phase,it is again validated that interference of light occurs only between the same photons possessing a set of the selfsame eigenvalues.

  6. Understanding ghost interference

    Science.gov (United States)

    Qureshi, Tabish; Chingangbam, Pravabati; Shafaq, Sheeba

    2016-08-01

    The ghost interference observed for entangled photons is theoretically analyzed using wave-packet dynamics. It is shown that ghost interference is a combined effect of virtual double-slit creation due to entanglement, and quantum erasure of which-path information for the interfering photon. For the case where the two photons are of different color, it is shown that fringe width of the interfering photon depends not only on its own wavelength, but also on the wavelength of the other photon which it is entangled with.

  7. Interference in immunoassay

    International Nuclear Information System (INIS)

    Interfering factors are evident in both limited reagent (radioimmunoassay) and excess reagent (immunometric assay) technologies and should be suspected whenever there is a discrepancy between analytical results and clinical findings in the investigation of particular diseases. The overall effect of interference in immunoassay is analytical bias in result, either positive or negative of variable magnitude. The interference maybe caused by a wide spectrum of factors from poor sample collection and handling to physiological factors e.g. lipaemia, heparin treatment, binding protein abnormalities, autoimmunity and drug treatments. The range of interfering factors is extensive and difficult to discuss effectively in a short review

  8. Laser Interference Lithography

    NARCIS (Netherlands)

    Wolferen, van Henk; Abelmann, Leon; Hennessy, Theodore C.

    2011-01-01

    In this chapter we explain how submicron gratings can be prepared by Laser Interference Lithography (LIL). In this maskless lithography technique, the standing wave pattern that exists at the intersection of two coherent laser beams is used to expose a photosensitive layer. We show how to build the

  9. Interference and radioastronomy

    Science.gov (United States)

    Thompson, A. R.; Vanden Bout, Paul A.; Gergely, Tomas E.

    1991-11-01

    The vulnerabilty of radio astronomy to the growing flood of interfering sources ranging from garage door openers to digital audio broadcast satellites is reviewed. Technical solutions to these problems are briefly examined, and work that needs to be done in the international regulatory system to ameliorate the interference is addressed. An overview is given of existing regulations.

  10. RNA interference in Lepidoptera

    DEFF Research Database (Denmark)

    Terenius, Ole; Papanicolaou, Alexie; Garbutt, Jennie S.;

    2011-01-01

    Gene silencing through RNA interference (RNAi) has revolutionized the study of gene function, particularly in non-model insects. However, in Lepidoptera (moths and butterflies) RNAi has many times proven to be difficult to achieve. Most of the negative results have been anecdotal and the positive...... public database at http://insectacentral.org/RNAi will continue to gather information on RNAi experiments. 2010 Elsevier Ltd. All rights reserved....

  11. Laser Interference Lithography

    OpenAIRE

    Wolferen, van, Henk A.G.M.; Abelmann, Leon; Hennessy, Theodore C.

    2011-01-01

    In this chapter we explain how submicron gratings can be prepared by Laser Interference Lithography (LIL). In this maskless lithography technique, the standing wave pattern that exists at the intersection of two coherent laser beams is used to expose a photosensitive layer. We show how to build the basic setup, with special attention for the optical aspects. The pros and cons of different types of resist as well as the limitations and errors of the setup are discussed. The bottleneck in Laser...

  12. RNA Interference in livestock

    OpenAIRE

    Merkl, Claudia

    2010-01-01

    RNA Interference (RNAi) allows experimental reduction of gene expression, providing a tool for the investigation of gene function, disease therapy and the generation of animal models for human diseases. RNAi offers an opportunity to carry out precise genetic manipulations in a wide variety of species. This thesis describes the use of RNAi to downregulate two porcine genes, the whey protein Beta-Lactoglobulin (BLG) and the tumor suppressor protein p53. BLG is a major component in porcine and r...

  13. Quantum Confined Fano Interference

    International Nuclear Information System (INIS)

    We study the transition from a dense continuum to a sparse quasicontinuum in the Fano problem. Transmission measurements on epitaxial layers of GaAs in a high magnetic field and calculations of the optical absorption show how the Fano interference disappears as quantum confinement discretizes the continuum states. The transition between quasi-one-dimensional and quasi-zero-dimensional systems occurs at length scales which are unusually large for optical experiments. copyright 1997 The American Physical Society

  14. Holographic interference filters

    Science.gov (United States)

    Diehl, Damon W.

    Holographic mirrors have wavelength-selection properties and thus qualify as a class of interference filters. Two theoretical methods for analyzing such structures are developed. The first method uses Hill's matrix method to yield closed-forms solutions in terms of the Floquet-Bloch waves within a periodic structure. A process is developed for implementing this solution method on a computer, using sparse-matrix memory allocation, numerical root-finding algorithms, and inverse-iteration techniques. It is demonstrated that Hill's matrix method is valid for the analysis of finite and multi-periodic problems. The second method of theoretical analysis is a transfer-matrix technique, which is herein termed thin-film decomposition. It is shown that the two methods of solution yield results that differ by, at worst, a fraction of a percent. Using both calculation techniques, a number of example problems are explored. Of key importance is the construction of a set of curves that are useful for the design and characterization of holographic interference filters. In addition to the theoretical development, methods are presented for the fabrication of holographic interference filters using DuPont HRF-800X001 photopolymer. Central to the exposure system is a frequency-stabilized, tunable dye laser. The types of filters fabricated include single-tone reflection filters, two types of multitone reflection filters, and reflection filters for infrared wavelengths. These filters feature index profiles that are not easily attainable through other fabrication methods. As a supplement to the body of the dissertation, the computer algorithms developed to implement Hill's matrix method and thin-film decomposition are also included as an appendix. Further appendices provide more information on Floquet's theorem and Hill's matrix method. A final appendix presents a design for an infrared laser spectrophotometer.

  15. Interference layer metallography

    International Nuclear Information System (INIS)

    Refractory metallic materials for application in Gas Cooled High Temperature Reactors are age-hardened nickel or iron base alloys. To control their behaviour and to adapt it to realistic load conditions, these materials have to be subjected to suitable informing tests and characterized. In the past few years, interference layer metallography has proved to be a highly flexible characterization procedure, suitable as an independent investigation method as well as an outstanding way of sample preparation for application of automatic quantitative image analysis to refractory alloys. This paper reports the problems of characterization of the Ni and Fe base alloys to be solved by interference layer metallography and the physical background of this method. The procedure of chromatic contrasting is discussed. From these considerations arises the result that for technical applications the optimum layer material for each special sample should be selected a priori. For that purpose it is necessary to measure the optical constants of the respective structural elements of the alloys as well as those of the candidate layer materials. The measuring procedures are discussed in detail. A routine procedure is deduced which allows to determine a priori the layer material and thickness fitting best to a given problem. (orig.)

  16. Beamforming design with proactive interference cancelation in MISO interference channels

    Science.gov (United States)

    Li, Yang; Tian, Yafei; Yang, Chenyang

    2015-12-01

    In this paper, we design coordinated beamforming at base stations (BSs) to facilitate interference cancelation at users in interference networks, where each BS is equipped with multiple antennas and each user is with a single antenna. By assuming that each user can select the best decoding strategy to mitigate the interference, either canceling the interference after decoding when it is strong or treating it as noise when it is weak, we optimize the beamforming vectors that maximize the sum rate for the networks under different interference scenarios and find the solutions of beamforming with closed-form expressions. The inherent design principles are then analyzed, and the performance gain over passive interference cancelation is demonstrated through simulations in heterogeneous cellular networks.

  17. Sensing via optical interference

    Directory of Open Access Journals (Sweden)

    Ryan C. Bailey

    2005-04-01

    Full Text Available Chemical and biological sensing are problems of tremendous contemporary technological importance in multiple regulatory and human health contexts, including environmental monitoring, water quality assurance, workplace air quality assessment, food quality control, many aspects of biodiagnostics, and, of course, homeland security. Frequently, what is needed, or at least wanted, are sensors that are simultaneously cheap, fast, reliable, selective, sensitive, robust, and easy to use. Unfortunately, these are often conflicting requirements. Over the past few years, however, a number of promising ideas based on optical interference effects have emerged. Each is based to some extent on advances in the design and fabrication of functional materials. Generally, the advances are of two kinds: chemo- and bio-selective recognition and binding, and efficient methods for micropatterning or microstructuring.

  18. Graphene quantum interference photodetector.

    Science.gov (United States)

    Alam, Mahbub; Voss, Paul L

    2015-01-01

    In this work, a graphene quantum interference (QI) photodetector was simulated in two regimes of operation. The structure consists of a graphene nanoribbon, Mach-Zehnder interferometer (MZI), which exhibits a strongly resonant transmission of electrons of specific energies. In the first regime of operation (that of a linear photodetector), low intensity light couples two resonant energy levels, resulting in scattering and differential transmission of current with an external quantum efficiency of up to 5.2%. In the second regime of operation, full current switching is caused by the phase decoherence of the current due to a strong photon flux in one or both of the interferometer arms in the same MZI structure. Graphene QI photodetectors have several distinct advantages: they are of very small size, they do not require p- and n-doped regions, and they exhibit a high external quantum efficiency.

  19. Graphene quantum interference photodetector

    Directory of Open Access Journals (Sweden)

    Mahbub Alam

    2015-03-01

    Full Text Available In this work, a graphene quantum interference (QI photodetector was simulated in two regimes of operation. The structure consists of a graphene nanoribbon, Mach–Zehnder interferometer (MZI, which exhibits a strongly resonant transmission of electrons of specific energies. In the first regime of operation (that of a linear photodetector, low intensity light couples two resonant energy levels, resulting in scattering and differential transmission of current with an external quantum efficiency of up to 5.2%. In the second regime of operation, full current switching is caused by the phase decoherence of the current due to a strong photon flux in one or both of the interferometer arms in the same MZI structure. Graphene QI photodetectors have several distinct advantages: they are of very small size, they do not require p- and n-doped regions, and they exhibit a high external quantum efficiency.

  20. Satellite-based interference analyzer

    Science.gov (United States)

    Varice, H.; Johannsen, K.; Sabaroff, S.

    1977-01-01

    System identifies terrestrial sources of radiofrequency interference and measures their frequency spectra and amplitudes. Designed to protect satellite communication networks, system measures entire noise spectrum over selected frequency band and can raster-scan geographical region to locate noise sources. Once interference is analyzed, realistic interference protection ratios are determined and mathematical models for predicting ratio-frequency noise spectra are established. This enhances signal-detection and locates optimum geographical positions and frequency bands for communication equipment.

  1. Quantum Interference in Graphene Nanoconstrictions.

    Science.gov (United States)

    Gehring, Pascal; Sadeghi, Hatef; Sangtarash, Sara; Lau, Chit Siong; Liu, Junjie; Ardavan, Arzhang; Warner, Jamie H; Lambert, Colin J; Briggs, G Andrew D; Mol, Jan A

    2016-07-13

    We report quantum interference effects in the electrical conductance of chemical vapor deposited graphene nanoconstrictions fabricated using feedback controlled electroburning. The observed multimode Fabry-Pérot interferences can be attributed to reflections at potential steps inside the channel. Sharp antiresonance features with a Fano line shape are observed. Theoretical modeling reveals that these Fano resonances are due to localized states inside the constriction, which couple to the delocalized states that also give rise to the Fabry-Pérot interference patterns. This study provides new insight into the interplay between two fundamental forms of quantum interference in graphene nanoconstrictions.

  2. Quantum Interference in Graphene Nanoconstrictions.

    Science.gov (United States)

    Gehring, Pascal; Sadeghi, Hatef; Sangtarash, Sara; Lau, Chit Siong; Liu, Junjie; Ardavan, Arzhang; Warner, Jamie H; Lambert, Colin J; Briggs, G Andrew D; Mol, Jan A

    2016-07-13

    We report quantum interference effects in the electrical conductance of chemical vapor deposited graphene nanoconstrictions fabricated using feedback controlled electroburning. The observed multimode Fabry-Pérot interferences can be attributed to reflections at potential steps inside the channel. Sharp antiresonance features with a Fano line shape are observed. Theoretical modeling reveals that these Fano resonances are due to localized states inside the constriction, which couple to the delocalized states that also give rise to the Fabry-Pérot interference patterns. This study provides new insight into the interplay between two fundamental forms of quantum interference in graphene nanoconstrictions. PMID:27295198

  3. A comparison of peak pressure interference factors interference factors for high-rise buildings determined in two ABL wind tunnels

    NARCIS (Netherlands)

    Bronkhorst, A.J.; Uffelen, M. van; Geurts, C.P.W.; Aanen, L.; Bentum, C.A. van

    2013-01-01

    Pressure measurements were performed on various configurations of two high-rise building models in two atmospheric boundary layer wind tunnels in the Netherlands. A comparison was made of the interference factors of the minimum and maximum peak pressures over all pressure taps at 0 degree angle of i

  4. Serum indices: managing assay interference.

    Science.gov (United States)

    Farrell, Christopher-John L; Carter, Andrew C

    2016-09-01

    Clinical laboratories frequently encounter samples showing significant haemolysis, icterus or lipaemia. Technical advances, utilizing spectrophotometric measurements on automated chemistry analysers, allow rapid and accurate identification of such samples. However, accurate quantification of haemolysis, icterus and lipaemia interference is of limited value if laboratories do not set rational alert limits, based on sound interference testing experiments. Furthermore, in the context of increasing consolidation of laboratories and the formation of laboratory networks, there is an increasing requirement for harmonization of the handling of haemolysis, icterus and lipaemia-affected samples across different analytical platforms. Harmonization may be best achieved by considering both the analytical aspects of index measurement and the possible variations in the effects of haemolysis, icterus and lipaemia interferences on assays from different manufacturers. Initial verification studies, followed up with ongoing quality control testing, can help a laboratory ensure the accuracy of haemolysis, icterus and lipaemia index results, as well as assist in managing any biases in index results from analysers from different manufacturers. Similarities, and variations, in the effect of haemolysis, icterus and lipaemia interference in assays from different manufacturers can often be predicted from the mechanism of interference. Nevertheless, interference testing is required to confirm expected similarities or to quantify differences. It is important that laboratories are familiar with a number of interference testing protocols and the particular strengths and weaknesses of each. A rigorous approach to all aspects of haemolysis, icterus and lipaemia interference testing allows the analytical progress in index measurement to be translated into improved patient care. PMID:27147624

  5. Output Interference in Recognition Memory

    Science.gov (United States)

    Criss, Amy H.; Malmberg, Kenneth J.; Shiffrin, Richard M.

    2011-01-01

    Dennis and Humphreys (2001) proposed that interference in recognition memory arises solely from the prior contexts of the test word: Interference does not arise from memory traces of other words (from events prior to the study list or on the study list, and regardless of similarity to the test item). We evaluate this model using output…

  6. The RNA interference revolution

    Directory of Open Access Journals (Sweden)

    G. Lenz

    2005-12-01

    Full Text Available The discovery of double-stranded RNA-mediated gene silencing has rapidly led to its use as a method of choice for blocking a gene, and has turned it into one of the most discussed topics in cell biology. Although still in its infancy, the field of RNA interference has already produced a vast array of results, mainly in Caenorhabditis elegans, but recently also in mammalian systems. Micro-RNAs are short hairpins of RNA capable of blocking translation, which are transcribed from genomic DNA and are implicated in several aspects from development to cell signaling. The present review discusses the main methods used for gene silencing in cell culture and animal models, including the selection of target sequences, delivery methods and strategies for a successful silencing. Expected developments are briefly discussed, ranging from reverse genetics to therapeutics. Thus, the development of the new paradigm of RNA-mediated gene silencing has produced two important advances: knowledge of a basic cellular mechanism present in the majority of eukaryotic cells and access to a potent and specific new method for gene silencing.

  7. Communications in interference limited networks

    CERN Document Server

    2016-01-01

    This book offers means to handle interference as a central problem of operating wireless networks. It investigates centralized and decentralized methods to avoid and handle interference as well as approaches that resolve interference constructively. The latter type of approach tries to solve the joint detection and estimation problem of several data streams that share a common medium. In fact, an exciting insight into the operation of networks is that it may be beneficial, in terms of an overall throughput, to actively create and manage interference. Thus, when handled properly, "mixing" of data in networks becomes a useful tool of operation rather than the nuisance as which it has been treated traditionally. With the development of mobile, robust, ubiquitous, reliable and instantaneous communication being a driving and enabling factor of an information centric economy, the understanding, mitigation and exploitation of interference in networks must be seen as a centrally important task.

  8. Reproductive interference between animal species.

    Science.gov (United States)

    Gröning, Julia; Hochkirch, Axel

    2008-09-01

    Although sexual interactions between species (reproductive interference) have been reported from a wide range of animal taxa, their potential for determining species coexistence is often disregarded. Here, we review evidence from laboratory and field studies illustrating that heterospecific sexual interactions are frequently associated with fitness loss and can have severe ecological and evolutionary consequences. We define reproductive interference as any kind of interspecific interaction during the process of mate acquisition that adversely affects the fitness of at least one of the species involved and that is caused by incomplete species recognition. We distinguish seven types of reproductive interference: signal jamming, heterospecific rivalry, misdirected courtship, heterospecific mating attempts, erroneous female choice, heterospecific mating, and hybridization. We then discuss the sex-specific costs of these types and highlight two typical features of reproductive interference: density-dependence and asymmetry. Similar to competition, reproductive interference can lead to displacement of one species (sexual exclusion), spatial, temporal, or habitat segregation, changes in life history parameters, and reproductive character displacement. In many cases, patterns of coexistence might be shaped by reproductive interference rather than by resource competition, as the presence of a few heterospecifics might substantially decrease reproductive success. Therefore, interspecific sexual interactions should receive more attention in ecological research. Reproductive interference has mainly been discussed in the context of invasive species or hybrid zones, whereas its influence on naturally-occurring sympatric species pairs has rarely been addressed. To improve our knowledge of the ecological significance of reproductive interference, findings from laboratory experiments should be validated in the field. Future studies should also focus on ecological mechanisms, such

  9. Numerical Simulation and Characteristics Analysis of Laser Self-Mixing Interference Measurement of Atmospheric Particle Parameters%大气颗粒物多参数激光自混合传感的数值模拟与特性分析

    Institute of Scientific and Technical Information of China (English)

    王秀利; 桂华侨; 陆亦怀; 刘建国; 王杰; 伍德侠

    2012-01-01

    基于颗粒物米氏散射特性、激光自混合三镜腔理论和激光器稳态条件,推导出在大气颗粒物光反馈下激光器频率、功率、线宽的理论表达式,建立了大气颗粒物光反馈下的激光自混合理论模型.同时,数值模拟和分析了大气颗粒物物理参数对激光自混合干涉信号的影响.结果表明,在一定粒径范围内,激光自混合反馈强度随大气颗粒物粒径增大先增大后减小,且反馈强度峰值出现的位置随颗粒物折射率实部的增大、虚部的减小向粒径较大处移动;自混合系统的外腔长度影响自混合干涉信号的波动深度,激光器输出光信号的幅值随外腔长度增大呈指数衰减;自混合干涉信号波动频率与大气颗粒物运动速度呈线性关系.分析结果对基于激光自混合效应的大气颗粒物多物理参数传感具有重要作用.%The theoretical expressions describing the self-mixing interference laser frequency, output power, and linewidth under the weak feedback of atmospheric particles are deduced based on the Mie scattering theory, the three-mirror theory and the steady-state equations of laser. The theory model of self-mixing effect feedback from atmospheric particles is established. And the relationship between the self-mixing signals and the physical parameters of atmospheric particles is analyzed in detail. The result shows that in a certain particle size range, the laser self-mixing signal intensity increases with the particle size and then decreases. With the increase of the real part and decrease of the imaginary part in atmospheric particle complex refractive index, the location of the external feedback strength peak value gradually moves to larger particle size. The amplitude of self-mixing signals is exponential decay with the increase of the external feedback cavity; the fluctuation frequency of the laser intensity is linearly related to the velocity of atmospheric particles. These

  10. Improved Interference Suppression Algorithm Against Broadband BPSK Interference

    Institute of Scientific and Technical Information of China (English)

    AN Jian-ping; XIA Cai-jie; WANG Ai-hua

    2008-01-01

    An improved polar exciser (IMPE) interference suppression method against broadband constant envelope binary phase shift keying (BPSK) interference is proposed. The disadvantage of traditional polar exciser (PE) is the performance degradation when the power of interference is low, i.e., the threshold effect. The proposed improved PE (IMPE) algorithm can overcome the threshold effect of PE by introducing compression gain (CG) metric, which forces PE suppressor active only at larger jammer-to-signal ratio (JSR) and switch to matched filter (MF) at lower JSR. Theoretical analysis and numerical simulations show the exactness of CG as a switching metric and the validity of the IMPE algorithm.

  11. Optical interference with digital holograms

    Science.gov (United States)

    Gossman, David; Perez-Garcia, Benjamin; Hernandez-Aranda, Raul I.; Forbes, Andrew

    2016-07-01

    In 1804, Thomas Young reported the observation of fringes in the intensity of light, and attributed it to the concept of interference between coherent sources. In this paper, we revisit this famous experiment and show how it can easily be demonstrated with digital holography. We look closely at the concept of interference with light and ask, "fringes in what?" We then show that depending on how light interferes, fringe patterns in observables other than intensity can be seen. We explain this conceptually and demonstrate it experimentally. We provide a holistic approach to the topic, aided by modern laboratory practices for a straightforward demonstration of the underlying physics.

  12. Profiler/satellite interference analysis

    Science.gov (United States)

    Chadwick, R. B.

    1987-02-01

    An engineering analysis of potential radio interference between the Wind Profiler Demonstration Network and three NOAA satellite-based systems is presented. These three systems are: Geostationary Operational Environmental Satellite (GOES) system, the Search and Rescue Satellite (SARSAT) system, and the TIROS series Data Collection System (TDCS). The Profiler considered in this analysis is the UHF Wind Profiler to be supplied by Sperry Corporation under a contract awarded June 1986. The analysis is based on the interference-to-noise ratio at the satellite receiver. Several engineering changes have been made to the original contract to reduce potential interference. The effects of these changes are presented.

  13. Quantum Erasure: Quantum Interference Revisited

    OpenAIRE

    Walborn, Stephen P.; Cunha, Marcelo O Terra; Pádua, Sebastião; Monken, Carlos H.

    2005-01-01

    Recent experiments in quantum optics have shed light on the foundations of quantum physics. Quantum erasers - modified quantum interference experiments - show that quantum entanglement is responsible for the complementarity principle.

  14. Interference of Quantum Market Strategies

    OpenAIRE

    Piotrowski, Edward W.; Jan Sladkowski; Jacek Syska

    2002-01-01

    Recent development in quantum computation and quantum information theory allows to extend the scope of game theory for the quantum world. The paper is devoted to the analysis of interference of quantum strategies in quantum market games.

  15. Interference of Quantum Market Strategies

    CERN Document Server

    Piotrowski, E W; Syska, J

    2003-01-01

    Recent development in quantum computation and quantum information theory allows to extend the scope of game theory for the quantum world. The paper is devoted to the analysis of interference of quantum strategies in quantum market games.

  16. Interference problems for nongeostationary satellites

    Science.gov (United States)

    Sollfrey, W.

    1984-01-01

    The interference problems faced by nongeostationary satellites may be of major significance. A general discussion indicates the scope of the problems and describes several configurations of importance. Computer programs are described, which are employed by NASA/JPL and the U.S. Air Force Satellite Control Facility to provide interference-free scheduling of commands and data transmission. Satellite system mission planners are not concerned with the precise prediction of interference episodes, but rather with the expected total amount of interference, the mean and maximum duration of events, and the mean spacing between episodes. The procedures in the theory of probability developed by the author which permit calculation of such quantities are described and applied to several real cases. It may be anticipated that the problems will become steadily worse in the future as more and more data transmissions attempt to occupy the same frequency band.

  17. Multipolar interference effects in nanophotonics

    CERN Document Server

    Liu, Wei

    2016-01-01

    Scattering of electromagnetic waves by an arbitrary nanoscale object can be characterized by a multipole decomposition of the electromagnetic field that allows to describe the scattering intensity and radiation pattern through interferences of dominating excited multipole modes. In modern nanophotonics, both generation and interference of multipole modes start to play an indispensable role, and they enable nanoscale manipulation of light with many related applications. Here we review the multipolar interference effects in metallic, metal-dielectric, and dielectric nanostructures, and suggest a comprehensive view on many phenomena involving the interferences of electric, magnetic and toroidal multipoles, which drive a number of recently discussed effects in nanophotonics such as unidirectional scattering, effective optical antiferromagnetism, generalized Kerker scattering with controlled angular patterns, generalized Brewster angle, and nonradiating optical anapoles. We further discuss other types of possible ...

  18. Electromagnetic Interference In New Aircraft

    Science.gov (United States)

    Larsen, William E.

    1991-01-01

    Report reviews plans to develop tests and standards to ensure that digital avionics systems in new civil aircraft immune to electromagnetic interference (EMI). Updated standards reflect more severe environment and vulnerabilities of modern avionics.

  19. Exploiting Interference through Algebraic Structure

    OpenAIRE

    Nazer, Bobak Anthony

    2009-01-01

    In a network, interference between transmitters is usually viewed as highly undesirable and clever algorithms and protocols have been devised to avoid it. Collectively, these strategies transform the physical layer into a set of reliable bit pipes which can then be used seamlessly by higher layers in the protocol stack. Unfortunately, interference avoidance results in sharply decreasing rates as the number of users increases. In this thesis, we develop a new tool, computation coding, that all...

  20. Interference between gestures and words

    OpenAIRE

    Langton, Stephen R. H.

    1996-01-01

    This thesis explores the idea that a speaker's gestural and verbal behaviours are mutually influential in the comprehension process. A Stroop-type interference paradigm was adopted as a tool for investigating whether or not listeners process to-be-ignored gestural information and how this information influences the processing of spoken words. In Experiments 1-4, static pointing (deictic) gestures and corresponding spoken and written words showed symmetrical interference. Incongruent words ...

  1. Advanced Interference Management Technique: Potentials and Limitations

    OpenAIRE

    Lee, Namyoon; Heath Jr, Robert W.

    2014-01-01

    Interference management has the potential to improve spectrum efficiency in current and next generation wireless systems (e.g. 3GPP LTE and IEEE 802.11). Recently, new paradigms for interference management have emerged to tackle interference in a general class of wireless networks: interference shaping and interference exploitation. Both approaches offer better performance in interference-limited communication regimes than traditionally thought possible. This article provides a high-level ove...

  2. On Feasibility of Interference Alignment in MIMO Interference Networks

    CERN Document Server

    Yetis, Cenk M; Jafar, Syed A; Kayran, Ahmet H

    2009-01-01

    We explore the feasibility of interference alignment in signal vector space -- based only on beamforming -- for K-user MIMO interference channels. Our main contribution is to relate the feasibility issue to the problem of determining the solvability of a multivariate polynomial system, considered extensively in algebraic geometry. It is well known, e.g. from Bezout's theorem, that generic polynomial systems are solvable if and only if the number of equations does not exceed the number of variables. Following this intuition, we classify signal space interference alignment problems as either proper or improper based on the number of equations and variables. Rigorous connections between feasible and proper systems are made through Bernshtein's theorem for the case where each transmitter uses only one beamforming vector. The multi-beam case introduces dependencies among the coefficients of a polynomial system so that the system is no longer generic in the sense required by both theorems. In this case, we show tha...

  3. Interference in motor learning - is motor interference sensory?

    DEFF Research Database (Denmark)

    Jensen, Jesper Lundbye; Petersen, Tue Hvass; Rothwell, John C;

    mechanisms determine whether or not interference occurs. We hypothesised that interference requires the same neural circuits to be engaged in the two tasks and provoke competing processes of synaptic plasticity. To test this, subjects learned a ballistic ankle plantarflexion task. Early motor memory......Skill gained after a short period of practice in one motor task can be abolished if a second task is learned shortly afterwards, but not all motor activities cause interference. After all it is not necessary to remain completely still after practicing a task for learning to occur. Here we ask which...... was disrupted by subsequent learning of a precision tracking task with the same agonist muscle group, but not by learning involving antagonist muscles or by voluntary agonist contractions that did not require learning. If the competing task was learned with the same agonist muscle group 4 hours following...

  4. Interference in ballistic motor learning - is motor interference really sensory?

    DEFF Research Database (Denmark)

    Lundbye-Jensen, Jesper; Petersen, Tue Hvass; Rothwell, John C;

    Skill gained after a short period of practice in one motor task can be abolished if a second task is learned shortly afterwards. We hypothesised that interference requires the same circuits to be engaged in the two tasks and provoke competing processes of synaptic plasticity. To test this, subjects...... learned a ballistic ankle plantarflexion task. Interference was observed following subsequent learning of a precision tracking task with the same movement direction and agonist muscles, but not by learning involving the opposite movement and antagonist muscles or by voluntary agonist contractions that did...

  5. Whirling waves in Interference experiments

    Science.gov (United States)

    Sinha, Urbasi; Sawant, Rahul; Samuel, Joseph; Sinha, Aninda; Sinha, Supurna

    2014-03-01

    In a double slit interference experiment, the wave function at the screen with both slits open is not exactly the sum of the wave functions with the slits individually open one at a time. The three scenarios represent three different boundary conditions and as such, the superposition principle should not be applicable. However, most well- known text books in quantum mechanics implicitly and/or explicitly use this assumption, the wave function hypothesis, which is only approximately true. In our present study, we have used the Feynman path integral formalism to quantify contributions from non-classical paths in interference experiments which provide a measurable deviation from the wave function hypothesis. A direct experimental demonstration for the existence of these non-classical paths is hard. We find that contributions from such paths can be significant and we propose simple three-slit interference experiments to directly confirm their existence. I will also describe some ongoing experimental efforts towards testing our theoretical findings.

  6. Interference of interacting matter waves

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsson, Mattias; Haller, Elmar; Mark, Manfred J; Danzl, Johann G; Hart, Russell; Naegerl, Hanns-Christoph [Institut fuer Experimentalphysik und Zentrum fuer Quantenphysik, Universitaet Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria); Daley, Andrew J, E-mail: christoph.naegerl@uibk.ac.a [Institut fuer Theoretische Physik und Zentrum fuer Quantenphysik, Universitaet Innsbruck, Technikerstrasse 25, A-6020 Innsbruck (Austria)

    2010-06-15

    The phenomenon of matter-wave interference lies at the heart of quantum physics. It has been observed in various contexts in the limit of non-interacting particles as a single-particle effect. Here we observe and control matter-wave interference whose evolution is driven by interparticle interactions. In a multi-path matter-wave interferometer, the macroscopic many-body wave function of an interacting atomic Bose-Einstein condensate develops a regular interference pattern, allowing us to detect and directly visualize the effect of interaction-induced phase shifts. We demonstrate control over the phase evolution by inhibiting interaction-induced dephasing and by refocusing a dephased macroscopic matter wave in a spin-echo-type experiment. Our results show that interactions in a many-body system lead to a surprisingly coherent evolution, possibly enabling narrow-band and high-brightness matter-wave interferometers based on atom lasers.

  7. "Quantum Interference with Slits" Revisited

    CERN Document Server

    Rothman, Tony

    2010-01-01

    Marcella [arXiv:quant-ph/0703126] has presented a straightforward technique employing the Dirac formalism to calculate single- and double-slit interference patterns. He claims that no reference is made to classical optics or scattering theory and that his method therefore provides a purely quantum mechanical description of these experiments. He also presents his calculation as if no approximations are employed. We show that he implicitly makes the same approximations found in classical treatments of interference and that no new physics has been introduced. At the same time, some of the quantum mechanical arguments Marcella gives are, at best, misleading.

  8. Interference of diffusive light waves.

    Science.gov (United States)

    Schmitt, J M; Knüttel, A; Knutson, J R

    1992-10-01

    We examine interference effects resulting from the superposition of photon-density waves produced by coherently modulated light incident upon a turbid medium. Photon-diffusion theory is used to derive expressions for the ac magnitude and phase of the aggregate diffusive wave produced in full- and half-space volumes by two sources. Using a frequency-domain spectrometer operating at 410 MHz, we verify interference patterns predicted by the model in scattering samples having optical properties similar to those of skin tissue. Potential imaging applications of interfering diffusive waves are discussed in the context of the theoretical and experimental results.

  9. "Quantum Interference with Slits" Revisited

    Science.gov (United States)

    Rothman, Tony; Boughn, Stephen

    2011-01-01

    Marcella has presented a straightforward technique employing the Dirac formalism to calculate single- and double-slit interference patterns. He claims that no reference is made to classical optics or scattering theory and that his method therefore provides a purely quantum mechanical description of these experiments. He also presents his…

  10. Interference in Cellular Satellite Systems

    OpenAIRE

    Kilic, Ozlem; Zaghloul, Amir I

    2010-01-01

    Co-channel beam interference in multi-beam satellite communications systems was investigated particularly for the downlink. Concept of frequency reuse was explained and the role of satellite antenna size and pattern was examined. Conventional spot beam coverage and its impact on determining the antenna size on board was discussed.

  11. Fano Interference in Classical Oscillators

    Science.gov (United States)

    Satpathy, S.; Roy, A.; Mohapatra, A.

    2012-01-01

    We seek to illustrate Fano interference in a classical coupled oscillator by using classical analogues of the atom-laser interaction. We present an analogy between the dressed state picture of coherent atom-laser interaction and a classical coupled oscillator. The Autler-Townes splitting due to the atom-laser interaction is analogous to the…

  12. REM sleep rescues learning from interference.

    Science.gov (United States)

    McDevitt, Elizabeth A; Duggan, Katherine A; Mednick, Sara C

    2015-07-01

    Classical human memory studies investigating the acquisition of temporally-linked events have found that the memories for two events will interfere with each other and cause forgetting (i.e., interference; Wixted, 2004). Importantly, sleep helps consolidate memories and protect them from subsequent interference (Ellenbogen, Hulbert, Stickgold, Dinges, & Thompson-Schill, 2006). We asked whether sleep can also repair memories that have already been damaged by interference. Using a perceptual learning paradigm, we induced interference either before or after a consolidation period. We varied brain states during consolidation by comparing active wake, quiet wake, and naps with either non-rapid eye movement sleep (NREM), or both NREM and REM sleep. When interference occurred after consolidation, sleep and wake both produced learning. However, interference prior to consolidation impaired memory, with retroactive interference showing more disruption than proactive interference. Sleep rescued learning damaged by interference. Critically, only naps that contained REM sleep were able to rescue learning that was highly disrupted by retroactive interference. Furthermore, the magnitude of rescued learning was correlated with the amount of REM sleep. We demonstrate the first evidence of a process by which the brain can rescue and consolidate memories damaged by interference, and that this process requires REM sleep. We explain these results within a theoretical model that considers how interference during encoding interacts with consolidation processes to predict which memories are retained or lost.

  13. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...... localities of tensions between matter and the immaterial, the practical and the ideal, and subject and object. In the colloquial language there can, moreover, often seem to be something authentic or genuine about atmosphere, juxtaposing it to staging, which is implied to be something simulated or artificial....... This introduction seeks to outline how a number of scholars have addressed the relationship between staged atmospheres and experience, and thus highlight both the philosophical, social and political aspects of atmospheres...

  14. Parasitic interference in nulling interferometry

    CERN Document Server

    Matter, Alexis; Danchi, William C; Lopez, Bruno; Absil, Olivier

    2013-01-01

    Nulling interferometry aims to detect faint objects close to bright stars. Its principle is to produce a destructive interference along the line-of-sight so that the stellar flux is rejected, while the flux of the off-axis source can be transmitted. In practice, various instrumental perturbations can degrade the nulling performance. Any imperfection in phase, amplitude, or polarization produces a spurious flux that leaks to the interferometer output and corrupts the transmitted off-axis flux. One of these instrumental pertubations is the crosstalk phenomenon, which occurs because of multiple parasitic reflections inside transmitting optics, and/or diffraction effects related to beam propagation along finite size optics. It can include a crosstalk of a beam with itself, and a mutual crosstalk between different beams. This can create a parasitic interference pattern, which degrades the intrinsic transmission map - or intensity response - of the interferometer. In this context, we describe how this instrumental ...

  15. Task duration in contextual interference.

    Science.gov (United States)

    Smith, Peter J K

    2002-12-01

    Duration of practice trial on a pursuit rotor task in contextual interference was investigated. Participants practiced at each of 4 angular velocities, with 24 participants completing 28 trials lasting 20 sec., and 24 participants completing 112 trials of 5 sec. Half of the participants in each trial-duration condition practiced in a blocked format and half practiced in a random format. After random practice posttest performance was better than blocked practice when practice-trial duration was 20 sec., but worse when practice-trial duration was 5 sec. This result is not consistent with theoretical explanations of the contextual interference effect and is discussed with reference to the task characteristics and demands of the pursuit rotor. PMID:12578255

  16. Fano interference in classical oscillators

    International Nuclear Information System (INIS)

    We seek to illustrate Fano interference in a classical coupled oscillator by using classical analogues of the atom-laser interaction. We present an analogy between the dressed state picture of coherent atom-laser interaction and a classical coupled oscillator. The Autler-Townes splitting due to the atom-laser interaction is analogous to the splitting of normal-mode frequencies of a coupled oscillator. Using this analogy, we simulate and experimentally demonstrate Fano interference and the associated phenomena in three-level atoms in a coupled electrical resonator circuit. This work aims to highlight analogies between classical and quantum systems for students at the postgraduate and graduate levels. Also, the reported technique can be easily realized in undergraduate laboratories. (paper)

  17. Interference in multilayer relativistic mirrors

    Science.gov (United States)

    Mirzanejhad, Saeed; Sohbatzadeh, Farshad; Babaei, Javad; Taghipour, Meisam; Mohammadzadeh, Zahra

    2015-10-01

    In this paper, reflection coefficient of a relativistic ultra-thin electron multilayer is calculated using electromagnetic interference procedures. The relativistic electron layers are assumed to be formed by nonlinear plasma wake waves that constitute the electron density cusps. It is shown that the interference between successive relativistic mirrors is restricted by the condition, τ p ≫ ( 2 γ 0 ) 5 / 2 / ω p 0 , where τp is the laser pulse duration. The results showed that tailoring the pulse amplitude, incident wave frequency value, incidence angle, and plasma density leads to increasing reflection coefficient a few orders of magnitudes. This constructive interference condition can be used for increasing conversion efficiency in the reflected energy from relativistic mirrors for the purpose of generating ultra-short coherence pulses in the extreme ultraviolet and x-ray regions. We also performed reflection from relativistic thin electron layers using relativistic 1D3V electromagnetic particle-in-cell (PIC) simulation. It was found that the results of PIC simulation are in agreement with analytical considerations.

  18. Continuous Time Channels with Interference

    CERN Document Server

    Ivan, Ioana; Thaler, Justin; Yuen, Henry

    2012-01-01

    Khanna and Sudan studied a natural model of continuous time channels where signals are corrupted by the effects of both noise and delay, and showed that, surprisingly, in some cases both are not enough to prevent such channels from achieving unbounded capacity. Inspired by their work, we consider channels that model continuous time communication with adversarial delay errors. The sender is allowed to subdivide time into arbitrarily large number $M$ of micro-units in which binary symbols may be sent, but the symbols are subject to unpredictable delays and may interfere with each other. We model interference by having symbols that land in the same micro-unit of time be summed, and a $k$-interference channels allows receivers to distinguish sums up to the value $k$. We consider both a channel adversary that has a limit on the maximum number of steps it can delay each symbol, and a more powerful adversary that only has a bound on the average delay. We give precise characterizations of the threshold between finite...

  19. Devices That May Interfere with Pacemakers

    Science.gov (United States)

    ... group of cellphone companies is studying that possibility. Bluetooth® headsets do not appear to interfere with pacemakers. ... group of cellphone companies is studying that possibility. Bluetooth® headsets do not appear to interfere with pacemakers. ...

  20. Photon wave functions and quantum interference experiments

    OpenAIRE

    Lapaire, G. G.; Sipe, J. E.

    2006-01-01

    We present a general theory to describe two-photon interference, including a formal description of few photon intereference in terms of single-photon amplitudes. With this formalism, it is possible to describe both frequency entangled and separable two-photon interference in terms of single-photon wave functions. Using this description, we address issues related to the physical interpretation of two-photon interference experiments. We include a discussion on how few-photon interference can be...

  1. Interference Alignment Using Variational Mean Field Annealing

    DEFF Research Database (Denmark)

    Badiu, Mihai Alin; Guillaud, Maxime; Fleury, Bernard Henri

    2014-01-01

    We study the problem of interference alignment in the multiple-input multiple- output interference channel. Aiming at minimizing the interference leakage power relative to the receiver noise level, we use the deterministic annealing approach to solve the optimization problem. In the corresponding...

  2. An accumulator model of semantic interference

    NARCIS (Netherlands)

    van Maanen, Leendert; van Rijn, Hedderik

    2007-01-01

    To explain latency effects in picture-word interference tasks, cognitive models need to account for both interference and stimulus onset asynchrony (SOA) effects. As opposed to most models of picture-word interference, which model the time course during the task in a ballistic manner, the RACE model

  3. Exoplanet Atmospheres

    CERN Document Server

    Seager, S

    2010-01-01

    At the dawn of the first discovery of exoplanets orbiting sun-like stars in the mid-1990s, few believed that observations of exoplanet atmospheres would ever be possible. After the 2002 Hubble Space Telescope detection of a transiting exoplanet atmosphere, many skeptics discounted it as a one-object, one-method success. Nevertheless, the field is now firmly established, with over two dozen exoplanet atmospheres observed today. Hot Jupiters are the type of exoplanet currently most amenable to study. Highlights include: detection of molecular spectral features; observation of day-night temperature gradients; and constraints on vertical atmospheric structure. Atmospheres of giant planets far from their host stars are also being studied with direct imaging. The ultimate exoplanet goal is to answer the enigmatic and ancient question, "Are we alone?" via detection of atmospheric biosignatures. Two exciting prospects are the immediate focus on transiting super Earths orbiting in the habitable zone of M-dwarfs, and u...

  4. Atmospheric Neutrinos

    OpenAIRE

    Takaaki Kajita

    2012-01-01

    Atmospheric neutrinos are produced as decay products in hadronic showers resulting from collisions of cosmic rays with nuclei in the atmosphere. Electron-neutrinos and muon-neutrinos are produced mainly by the decay chain of charged pions to muons to electrons. Atmospheric neutrino experiments observed zenith angle and energy-dependent deficit of muon-neutrino events. It was found that neutrino oscillations between muon-neutrinos and tau-neutrinos explain these data well. This paper discusses...

  5. Articulating Atmospheres

    DEFF Research Database (Denmark)

    Kinch, Sofie

    2011-01-01

    This paper presents an architectural approach to designing computational interfaces by articulating the notion of atmosphere in the field of interaction design. It draws upon the concept of kinesthetic interaction and a philosophical notion on atmosphere emphasizing the importance of bodily...... experience in space, presented as middle ground experience. In the field of HCI, middle ground experiences complete the unarticulated spectrum between designing for foreground of attention or background awareness. When “Articulating Atmospheres through Middle Ground Experiences in Interaction Design...

  6. Pluto's atmosphere

    International Nuclear Information System (INIS)

    Airborne CCD photometer observations of Pluto's June 9, 1988 stellar occultation have yielded an occultation lightcurve, probing two regions on the sunrise limb 2000 km apart, which reveals an upper atmosphere overlying an extinction layer with an abrupt upper boundary. The extinction layer may surround the entire planet. Attention is given to a model atmosphere whose occultation lightcurve closely duplicates observations; fits of the model to the immersion and emersion lightcurves exhibit no significant derived atmosphere-structure differences. Assuming a pure methane atmosphere, surface pressures of the order of 3 microbars are consistent with the occultation data. 43 references

  7. Atmospheric electricity

    CERN Document Server

    Chalmers, J Alan

    1957-01-01

    Atmospheric Electricity brings together numerous studies on various aspects of atmospheric electricity. This book is composed of 13 chapters that cover the main problems in the field, including the maintenance of the negative charge on the earth and the origin of the charges in thunderstorms. After a brief overview of the historical developments of atmospheric electricity, this book goes on dealing with the general principles, results, methods, and the MKS system of the field. The succeeding chapters are devoted to some aspects of electricity in the atmosphere, such as the occurrence and d

  8. Codebook-based interference alignment for uplink MIMO interference channels

    KAUST Repository

    Lee, Hyun Ho

    2014-02-01

    In this paper, we propose a codebook-based interference alignment (IA) scheme in the constant multiple-input multipleoutput (MIMO) interference channel especially for the uplink scenario. In our proposed scheme, we assume cooperation among base stations (BSs) through reliable backhaul links so that global channel knowledge is available for all BSs, which enables BS to compute the transmit precoder and inform its quantized index to the associated user via limited rate feedback link.We present an upper bound on the rate loss of the proposed scheme and derive the scaling law of the feedback load tomaintain a constant rate loss relative to IA with perfect channel knowledge. Considering the impact of overhead due to training, cooperation, and feedback, we address the effective degrees of freedom (DOF) of the proposed scheme and derive the maximization of the effective DOF. From simulation results, we verify our analysis on the scaling law to preserve the multiplexing gain and confirm that the proposed scheme is more effective than the conventional IA scheme in terms of the effective DOF. © 2014 KICS.

  9. INTERFERENCE CANCELLATION FOR MOBILE DISPERSIVE CHANNELS

    Institute of Scientific and Technical Information of China (English)

    Kazi Takpaya

    2003-01-01

    A robust interference canceller for Multi-Carrier Code Division Multiple Access(MC-CDMA) using Orthogonal Frequency Division Multiplexing (OFDM) in Rayleigh fading isproposed. This interference canceller is robust in the sense that it cancels Inter-Carriers Inter-ference (ICI) and is suitable for use in dispersive channels. To come up the effects of the signaldispersion, Doppler shifts and delay spreads on the performance of MC-CDMA systems over mo-bile fading channels, this interference canceller exploits the merit of the orthogonal signaling andpilot signals to evaluate the channel parameters. This interface canceller is well suited to work initerative turbo interference cancellation.

  10. IETS and quantum interference: propensity rules in the presence of an interference feature.

    Science.gov (United States)

    Lykkebo, Jacob; Gagliardi, Alessio; Pecchia, Alessandro; Solomon, Gemma C

    2014-09-28

    Destructive quantum interference in single molecule electronics is an intriguing phenomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference effects in the transmission lead to either low current or a particular line shape in current-voltage curves, depending on the position of the interference feature. Second, we consider how inelastic electron tunneling spectroscopy can be used to probe the presence of an interference feature by identifying vibrational modes that are selectively suppressed when quantum interference effects dominate. That is, we expand the understanding of propensity rules in inelastic electron tunneling spectroscopy to molecules with destructive quantum interference. PMID:25273424

  11. IETS and quantum interference: Propensity rules in the presence of an interference feature

    Energy Technology Data Exchange (ETDEWEB)

    Lykkebo, Jacob; Solomon, Gemma C., E-mail: gsolomon@nano.ku.dk [Nano-Science Center and Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø (Denmark); Gagliardi, Alessio [Technische Universität München, Electrical Engineering and Information Tech., Arcisstr. 21, 80333 München (Germany); Pecchia, Alessandro [Consiglio Nazionale delle Ricerche, ISMN, Via Salaria km 29.6, 00017 Monterotondo (Rome) (Italy)

    2014-09-28

    Destructive quantum interference in single molecule electronics is an intriguing phenomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference effects in the transmission lead to either low current or a particular line shape in current-voltage curves, depending on the position of the interference feature. Second, we consider how inelastic electron tunneling spectroscopy can be used to probe the presence of an interference feature by identifying vibrational modes that are selectively suppressed when quantum interference effects dominate. That is, we expand the understanding of propensity rules in inelastic electron tunneling spectroscopy to molecules with destructive quantum interference.

  12. IETS and quantum interference: Propensity rules in the presence of an interference feature

    International Nuclear Information System (INIS)

    Destructive quantum interference in single molecule electronics is an intriguing phenomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference effects in the transmission lead to either low current or a particular line shape in current-voltage curves, depending on the position of the interference feature. Second, we consider how inelastic electron tunneling spectroscopy can be used to probe the presence of an interference feature by identifying vibrational modes that are selectively suppressed when quantum interference effects dominate. That is, we expand the understanding of propensity rules in inelastic electron tunneling spectroscopy to molecules with destructive quantum interference

  13. INTERFERENCE OF UNIDIRECTIONAL SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-05-01

    Full Text Available Subject of study.We consider interference of unidirectional shock waves or, as they are called, catching up shock waves. The scope of work is to give a classification of the shock-wave structures that arise in this type of interaction of shock waves, and the area of their existence. Intersection of unidirectional shock waves results in arising of a shock-wave structure at the intersection point, which contains the main shock wave, tangential discontinuity and one more reflected gas-dynamic discontinuity of unknown beforehand type. The problem of determining the type of reflected discontinuity is the main problem that one has to solve in the study of catching shock waves interference. Main results.The paper presents the pictures of shock-wave structures arising at the interaction of catching up shock waves. The areas with a regular and irregular unidirectional interaction of shocks are described. Characteristic shock-wave structures are of greatest interest, where reflected gas-dynamic discontinuity degenerates into discontinuous characteristics. Such structures have a number of extreme properties. We have found the areas of existence for such shock-wave structures. There are also areas in which the steady-state solution is not available. The latter has determined revival of interest for the theoretical study of the problem, because the facts of sudden shock-wave structure destruction inside the air intake of supersonic aircrafts at high Mach numbers have been discovered. Practical significance.The theory of interference for unidirectional shock waves and design procedure are usable in the design of supersonic air intakes. It is also relevant for application possibility investigation of catching up oblique shock waves to create overcompressed detonation in perspective detonation air-jet and rocket engines.

  14. Long working distance interference microscope

    Science.gov (United States)

    Sinclair, Michael B.; DeBoer, Maarten P.; Smith, Norman F.

    2004-04-13

    Disclosed is a long working distance interference microscope suitable for three-dimensional imaging and metrology of MEMS devices and test structures on a standard microelectronics probe station. The long working distance of 10-30 mm allows standard probes or probe cards to be used. This enables nanometer-scale 3-D height profiles of MEMS test structures to be acquired across an entire wafer. A well-matched pair of reference/sample objectives is not required, significantly reducing the cost of this microscope, as compared to a Linnik microinterferometer.

  15. Embracing interference in wireless systems

    CERN Document Server

    Gollakota, Shyamnath

    2014-01-01

    The wireless medium is a shared resource. If nearby devices transmit at thesame time, their signals interfere, resulting in a collision. In traditionalnetworks, collisions cause the loss of the transmitted information. For thisreason, wireless networks have been designed with the assumption thatinterference is intrinsically harmful and must be avoided.This book, a revised version of the author's award-winning Ph.D.dissertation, takes an alternate approach: Instead of viewing interferenceas an inherently counterproductive phenomenon that should to be avoided, wedesign practical systems that tra

  16. Interference Mitigation in Cognitive Femtocells

    DEFF Research Database (Denmark)

    Da Costa, Gustavo Wagner Oliveira; Cattoni, Andrea Fabio; Alvarez Roig, Victor;

    2010-01-01

    in densely deployed femto scenarios. In this paper, two key elements of cognitive femtocells are combined: a power control algorithm and a fully distributed dynamic spectrum allocation method. The resulting solution was evaluated through system-level simulations and compared to the separate algorithms......, management and optimization can be prohibitive. Instead, self-optimization of an uncoordinated deployment should be considered. Cognitive Radio enabled femtocells are considered to be a promising solution to enable self-optimizing femtocells to effectively manage the inter-cell interference, especially...

  17. Assessment of life interference in anxious children

    DEFF Research Database (Denmark)

    Rapee, Ronald; Thastum, Mikael; Chavira, Denise

    . This imbalance has particularly characterised research on child anxiety where few studies have examined either the impact of anxiety disorders on children's lives or the effects of treatments on life interference. To some extent this lack of attention has come from a lack of well developed measures to assess...... life interference derived from symptoms of anxiety. Broader and more general life interference measures tend to have minimal relevance for children with anxiety disorders. The current paper will describe two measures of life interference that have been developed at the Centre for Emotional Health...... directed at children and adolescents. One measure, the Children's Anxiety Life Interference Scale (CALIS) was developed to assess interference directly associated with symptoms of anxiety in children and adolescents, while the other, the Adolescent Life Interference Scale (ALIS) is a broader measure...

  18. Interference Mitigation in Large Random Wireless Networks

    CERN Document Server

    Aldridge, Matthew

    2011-01-01

    A central problem in the operation of large wireless networks is how to deal with interference -- the unwanted signals being sent by transmitters that a receiver is not interested in. This thesis looks at ways of combating such interference. In Chapters 1 and 2, we outline the necessary information and communication theory background, including the concept of capacity. We also include an overview of a new set of schemes for dealing with interference known as interference alignment, paying special attention to a channel-state-based strategy called ergodic interference alignment. In Chapter 3, we consider the operation of large regular and random networks by treating interference as background noise. We consider the local performance of a single node, and the global performance of a very large network. In Chapter 4, we use ergodic interference alignment to derive the asymptotic sum-capacity of large random dense networks. These networks are derived from a physical model of node placement where signal strength d...

  19. Ramsey interference with single photons

    CERN Document Server

    Clemmen, Stéphane; Ramelow, Sven; Gaeta, Alexander L

    2016-01-01

    Interferometry using discrete energy levels in nuclear, atomic or molecular systems is the foundation for a wide range of physical phenomena and enables powerful techniques such as nuclear magnetic resonance, electron spin resonance, Ramsey-based spectroscopy and laser/maser technology. It also plays a unique role in quantum information processing as qubits are realized as energy superposition states of single quantum systems. Here, we demonstrate quantum interference of different energy states of single quanta of light in full analogy to energy levels of atoms or nuclear spins and implement a Ramsey interferometer with single photons. We experimentally generate energy superposition states of a single photon and manipulate them with unitary transformations to realize arbitrary projective measurements, which allows for the realization a high-visibility single-photon Ramsey interferometer. Our approach opens the path for frequency-encoded photonic qubits in quantum information processing and quantum communicati...

  20. RNA interference and antiviral therapy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    RNA interference (RNAi) is an evolutionally conserved gene silencing mechanism present in a variety of eukaryotic species. RNAi uses short double-stranded RNA (dsRNA) to trigger degradation or translation repression of homologous RNA targets in a sequence-specific manner. This system can be induced effectively in vitro and in vivo by direct application of small interfering RNAs (siRNAs), or by expression of short hairpin RNA (shRNA) with non-viral and viral vectors. To date, RNAi has been extensively used as a novel and effective tool for functional genomic studies, and has displayed great potential in treating human diseases, including human genetic and acquired disorders such as cancer and viral infections. In the present review, we focus on the recent development in the use of RNAi in the prevention and treatment of viral infections. The mechanisms,strategies, hurdles and prospects of employing RNAi in the pharmaceutical industry are also discussed.

  1. Collision-induced constructive quantum interference

    International Nuclear Information System (INIS)

    We theoretically study the collision-induced constructive quantum interference in an open four-level system with the density-matrix approach based on the experimental observation of constructive quantum interference between two transition pathways 3P1/2-5S (or 4D) and 3P3/2-5S (or 4D) via equal-frequency hybrid excitation in the Na2-Na system. The effects of the collision-induced coherent and incoherent decay rates and the ratio of the two transition dipole moments on the interference are analyzed. It is shown that through the incoherent process (collision), the coherence between a widely separated doublet and subsequent constructive quantum interference can be realized. The physical origin of the constructive interference can be seen clearly in the dressed-atom picture. The theoretical results can also be used to qualitatively explain the dependence of quantum interference on the experimental buffer gas pressure and sample temperature

  2. Exoplanetary Atmospheres

    CERN Document Server

    Madhusudhan, Nikku; Fortney, Jonathan; Barman, Travis

    2014-01-01

    The study of exoplanetary atmospheres is one of the most exciting and dynamic frontiers in astronomy. Over the past two decades ongoing surveys have revealed an astonishing diversity in the planetary masses, radii, temperatures, orbital parameters, and host stellar properties of exoplanetary systems. We are now moving into an era where we can begin to address fundamental questions concerning the diversity of exoplanetary compositions, atmospheric and interior processes, and formation histories, just as have been pursued for solar system planets over the past century. Exoplanetary atmospheres provide a direct means to address these questions via their observable spectral signatures. In the last decade, and particularly in the last five years, tremendous progress has been made in detecting atmospheric signatures of exoplanets through photometric and spectroscopic methods using a variety of space-borne and/or ground-based observational facilities. These observations are beginning to provide important constraints...

  3. Atmospheric composition

    Science.gov (United States)

    Daniels, G. E.

    1973-01-01

    The earth's atmosphere is made up of a number of gases in different relative amounts. Near sea level and up to about 90 km, the amount of these atmospheric gases in clean, relatively dry air is practically constant. Four of these gases, nitrogen, oxygen, argon, and carbon dioxide, make up 99.99 percent by volume of the atmosphere. Two gases, ozone and water vapor, change in relative amounts, but the total amount of these two is very small compared to the amount of the other gases. The atmospheric composition shown in a table can be considered valid up to 90 km geometric altitude. Above 90 km, mainly because of molecular dissociation and diffusive separation, the composition changes.

  4. Coping with Radio Frequency Interference

    Science.gov (United States)

    Lewis, B. M.

    2009-01-01

    The radio spectrum is a finite resource, on which humanity makes many demands. And pressure on it is ever increasing with the development of new technology and ideas for radio services. After all, we all benefit from wifi and cell phones. Radio astronomers have a small percentage of the spectrum allocated to them at octave intervals in the metre-centimetre bands, and at important frequencies, such as that of the 21cm line of HI. Signals from other services, as well as from our own poorly-engineered equipment, sometimes contaminate our bands: these signals constitute RFI. These may totally obliterate the astronomical signal, or, in the case of CLOUDSAT, may be capable of completely destroying a receiver, which introduces us to the new possibility of 'destructive interference'. A geo-stationary satellite can block access to a piece of sky from one site. Good equipment design eliminates self-inflicted interference, while physical separation often provides adequate practical mitigation at many frequencies. However, new observatories end up being located in the West Australian desert or Antarctica. In future they may be on the back side of the Moon. But there is no Earth-bound protection via physical separation against satellite signals. Some mitigation can be achieved by frequent data dumps and the excision of RFI, or by real-time detection and blanking of the receiver, or by more sophisticated algoriths. Astronomers of necessity aim to achieve mitigation via coordination, at the local level, and by participating in spectrum management at the national and international levels. This involves them spending a lot of time in Geneva at the International Telegraphic Union protecting their access to spectrum, and access to clean spectrum from the L3 point and the far side of the Moon.

  5. Filtering algorithm for dotted interferences

    Energy Technology Data Exchange (ETDEWEB)

    Osterloh, K., E-mail: kurt.osterloh@bam.de [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Buecherl, T.; Lierse von Gostomski, Ch. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany); Zscherpel, U.; Ewert, U. [Federal Institute for Materials Research and Testing (BAM), Division VIII.3, Radiological Methods, Unter den Eichen 87, 12205 Berlin (Germany); Bock, S. [Technische Universitaet Muenchen, Lehrstuhl fuer Radiochemie, Walther-Meissner-Str. 3, 85748 Garching (Germany)

    2011-09-21

    An algorithm has been developed to remove reliably dotted interferences impairing the perceptibility of objects within a radiographic image. This particularly is a major challenge encountered with neutron radiographs collected at the NECTAR facility, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II): the resulting images are dominated by features resembling a snow flurry. These artefacts are caused by scattered neutrons, gamma radiation, cosmic radiation, etc. all hitting the detector CCD directly in spite of a sophisticated shielding. This makes such images rather useless for further direct evaluations. One approach to resolve this problem of these random effects would be to collect a vast number of single images, to combine them appropriately and to process them with common image filtering procedures. However, it has been shown that, e.g. median filtering, depending on the kernel size in the plane and/or the number of single shots to be combined, is either insufficient or tends to blur sharp lined structures. This inevitably makes a visually controlled processing image by image unavoidable. Particularly in tomographic studies, it would be by far too tedious to treat each single projection by this way. Alternatively, it would be not only more comfortable but also in many cases the only reasonable approach to filter a stack of images in a batch procedure to get rid of the disturbing interferences. The algorithm presented here meets all these requirements. It reliably frees the images from the snowy pattern described above without the loss of fine structures and without a general blurring of the image. It consists of an iterative, within a batch procedure parameter free filtering algorithm aiming to eliminate the often complex interfering artefacts while leaving the original information untouched as far as possible.

  6. Quantum interference from remotely trapped ions

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, S; Rotter, D; Hennrich, M; Blatt, R [Institute for Experimental Physics, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria); Rohde, F; Schuck, C; Almendros, M; Gehr, R; Dubin, F; Eschner, J [ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, Av del Canal OlImpic, E-08860 Castelldefels (Spain)], E-mail: francois.dubin@icfo.es

    2009-01-15

    We observe quantum interference of photons emitted by two continuously laser-excited single ions, independently trapped in distinct vacuum vessels. High contrast two-photon interference is observed in two experiments with different ion species, Ca{sup +} and Ba{sup +}. Our experimental findings are quantitatively reproduced by Bloch equation calculations. In particular, we show that the coherence of the individual resonance fluorescence light field is determined from the observed interference.

  7. Interference Coordination for Dense Wireless Networks

    DEFF Research Database (Denmark)

    Soret, Beatriz; Pedersen, Klaus I.; Jørgensen, Niels T.K.;

    2015-01-01

    The promise of ubiquitous and super-fast connectivity for the upcoming years will be in large part fulfilled by the addition of base stations and spectral aggregation. The resulting very dense networks (DenseNets) will face a number of technical challenges. Among others, the interference emerges...... simply react to an identified interference problem. As an example, we propose two algorithms to apply time domain and frequency domain small cell interference coordination in a DenseNet....

  8. Suppression of Strong Background Interference on E-Nose Sensors in an Open Country Environment.

    Science.gov (United States)

    Tian, Fengchun; Zhang, Jian; Yang, Simon X; Zhao, Zhenzhen; Liang, Zhifang; Liu, Yan; Wang, Di

    2016-02-16

    The feature extraction technique for an electronic nose (e-nose) applied in tobacco smell detection in an open country/outdoor environment with periodic background strong interference is studied in this paper. Principal component analysis (PCA), Independent component analysis (ICA), re-filtering and a priori knowledge are combined to separate and suppress background interference on the e-nose. By the coefficient of multiple correlation (CMC), it can be verified that a better separation of environmental temperature, humidity, and atmospheric pressure variation related background interference factors can be obtained with ICA. By re-filtering according to the on-site interference characteristics a composite smell curve was obtained which is more related to true smell information based on the tobacco curer's experience.

  9. Using Interference to Block RFID Tags

    DEFF Research Database (Denmark)

    Krigslund, Rasmus; Popovski, Petar; Pedersen, Gert Frølund;

    We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag.......We propose a novel method to block RFID tags from responding, using intentional interference. We focus on the experimental evaluation, where we impose interference on the download and uplink, respectively. The results are positive, where modulated CCI shows most effective to block a tag....

  10. Impact of MIMO Co-Channel Interference

    DEFF Research Database (Denmark)

    Rahman, Muhammad Imadur; De Carvalho, Elisabeth; Prasad, Ramjee

    2007-01-01

    to cellular interference of some specific Multiple Input Multiple Output (MIMO) schemes on the same and other MIMO schemes. The goal is to study the impact of interference from MIMO schemes at a user located in the cell edge. Semi-Analytical evaluations of Signal to Interference and Noise Ratio (SINR) is done...... to find out the SINR statistics of different combinations of desired and interfering links. We have studied linear combining receivers for all the link combinations. Based on the current analysis, it is found that Space-Time Block Code (STBC) is a severe interferer compared to others, and specific...

  11. Quantum Interference in Three Photon Down Conversion

    CERN Document Server

    Banaszek, K; Banaszek, Konrad; Knight, Peter L.

    1997-01-01

    We study degenerate three photon down conversion as a potential scheme for generating nonclassical states of light which exhibit clear signatures of phase space interference. The Wigner function representing these states contains an interference pattern manifesting quantum coherence between distinct phase space components, and has substantial areas of negativity. We develop an analytical description of the interference pattern, which demonstrates how the oscillations of the Wigner function are built up by the superposition principle. We analyze the impact of dissipation and pump fluctuations on the visibility of the interference pattern; the results suggest that some signatures of quantum coherence can be observed in the presence of moderate amount of noise.

  12. Atmospheric Photochemistry

    Science.gov (United States)

    Massey, Harrie; Potter, A. E.

    1961-01-01

    The upper atmosphere offers a vast photochemical laboratory free from solid surfaces, so all reactions take place in the gaseous phase. At 30 km altitude the pressure has fallen to about one-hundredth of that at ground level, and we shall, rather arbitrarily, regard the upper atmosphere as beginning at that height. By a little less than 100 km the pressure has fallen to 10(exp -3) mm Hg and is decreasing by a power of ten for every 15 km increase in altitude. Essentially we are concerned then with the photochemistry of a nitrogen-oxygen mixture under low-pressure conditions in which photo-ionization, as well as photodissociation, plays an important part. Account must also be taken of the presence of rare constituents, such as water vapour and its decomposition products, including particularly hydroxyl, oxides of carbon, methane and, strangely enough, sodium, lithium and calcium. Many curious and unfamiliar reactions occur in the upper atmosphere. Some of them are luminescent, causing the atmosphere to emit a dim light called the airglow. Others, between gaseous ions and neutral molecules, are almost a complete mystery at this time. Similar interesting phenomena must occur in other planetary atmospheres, and they might be predicted if sufficient chemical information were available.

  13. INTERFERENCE OF COUNTERPROPAGATING SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-03-01

    -dynamic discontinuities, the intensities corresponding to the transition from regular to irregular interference were described. Numerical calculations of the shock-wave structure transformation in the conditions of hysteresis were performed. The results were compared with the experiments carried out by hydraulic analogy method. Practical significance. Results of the work complement well the theory of stationary gas-dynamic discontinuities interference and can be used at designing of perspective images of supersonic and hypersonic aircraft.

  14. IETS and quantum interference: propensity rules in the presence of an interference feature

    OpenAIRE

    Lykkebo, Jacob; Gagliardi, Alessio; Pecchia, Alessandro; Gemma C. Solomon

    2014-01-01

    Destructive quantum interference in single molecule electronics is an intriguing phe- nomenon; however, distinguishing quantum interference effects from generically low transmission is not trivial. In this paper, we discuss how quantum interference ef- fects in the transmission lead to either low current or a particular line shape in current-voltage curves, depending on the position of the interference feature. Sec- ondly, we consider how inelastic electron tunneling spectroscopy can be used ...

  15. Atmospheric thermodynamics

    CERN Document Server

    Iribarne, J V

    1973-01-01

    The thermodynamics of the atmosphere is the subject of several chapters in most textbooks on dynamic meteorology, but there is no work in English to give the subject a specific and more extensive treatment. In writing the present textbook, we have tried to fill this rather remarkable gap in the literature related to atmospheric sciences. Our aim has been to provide students of meteorology with a book that can playa role similar to the textbooks on chemical thermodynamics for the chemists. This implies a previous knowledge of general thermodynamics, such as students acquire in general physics courses; therefore, although the basic principles are reviewed (in the first four chapters), they are only briefly discussed, and emphasis is laid on those topics that will be useful in later chapters, through their application to atmospheric problems. No attempt has been made to introduce the thermodynamics of irreversible processes; on the other hand, consideration of heterogeneous and open homogeneous systems permits a...

  16. Quantum theory of two-photon interference

    OpenAIRE

    Wu, Xiang-Yao; Zhang, Bo-Jun; Liu, Xiao-Jing; LI Hong; Zhang, Si-Qi; Jing WANG; Wu, Yi-Heng; Li, Jing-Wu

    2012-01-01

    In this paper, we study two-photon interference with the approach of photon quantum theory, with specific attention to the two-photon interference experiment carried out by Milena D'Angelo et al. (Phys. Rev. Lett 87:013602, 2001). We find the theoretical result is accordance with experiment data.

  17. The Nature and Diagnosis of Interference Phenomena.

    Science.gov (United States)

    Denison, Norman

    1966-01-01

    The recognition of the systematic nature of the interference of the mother tongue when learning a second language is among the most significant advances in linguistics for the teaching and learning of foreign languages. The work of Weinreich showed that interference between language systems--the absorption of loan words, calques, and phonological,…

  18. Interference and the Law of Energy Conservation

    Science.gov (United States)

    Drosd, Robert; Minkin, Leonid; Shapovalov, Alexander S.

    2014-01-01

    Introductory physics textbooks consider interference to be a process of redistribution of energy from the wave sources in the surrounding space resulting in constructive and destructive interferences. As one can expect, the total energy flux is conserved. However, one case of apparent non-conservation energy attracts great attention. Imagine that…

  19. 47 CFR 74.604 - Interference avoidance.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Interference avoidance. 74.604 Section 74.604 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) BROADCAST RADIO SERVICES EXPERIMENTAL RADIO... Stations § 74.604 Interference avoidance. (a) (b) Where two or more licensees are assigned a common...

  20. Is There Semantic Interference in Delayed Naming?

    Science.gov (United States)

    Madebach, Andreas; Oppermann, Frank; Hantsch, Ansgar; Curda, Christian; Jescheniak, Jorg D.

    2011-01-01

    The semantic interference effect in the picture-word interference task is interpreted as an index of lexical competition in prominent speech production models. Janssen, Schirm, Mahon, and Caramazza (2008) challenged this interpretation on the basis of experiments with a novel version of this task, which introduced a task-switching component.…

  1. ``Quantum'' interference with bouncing drops

    Science.gov (United States)

    Bohr, Tomas; Andersen, Anders; Madsen, Jacob; Reichelt, Christian; Lautrup, Benny; Ellegaard, Clive; Levinsen, Mogens

    2013-11-01

    In a series of recent papers (most recently) Yves Couder and collaborators have explored the dynamics of walking drops on the surface of a vibrated bath of silicon oil and have demonstrated a close analogy to quantum phenomena. The bouncing drop together with the surface wave that it excites seems to be very similar to the pilot wave envisaged by de Broglie for quantum particles. In particular, have studied a double slit experiment with walking drops, where an interference pattern identical to the quantum version is found even though it is possible to follow the orbits of the drops and unambigously determine which slit it goes through, something which in quantum mechanics would be ruled out by the Heisenberg uncertainly relations. We have repeated the experiment and present a somewhat more complicated picture. Theoretically, we study a Schrödinger equation with a source term originating from a localised ``particle'' being simultaneously guided by the wave. We present simple solutions to such a field theory and discuss the fundamental difficulties met by such a theory in order to comply with quantum mechanics.

  2. Interference Channels with Strong Secrecy

    CERN Document Server

    He, Xiang

    2009-01-01

    It is known that given the real sum of two independent uniformly distributed lattice points from the same nested lattice codebook, the eavesdropper can obtain at most 1 bit of information per channel regarding the value of one of the lattice points. In this work, we study the effect of this 1 bit information on the equivocation expressed in three commonly used information theoretic measures, i.e., the Shannon entropy, the Renyi entropy and the min entropy. We then demonstrate its applications in an interference channel with a confidential message. In our previous work, we showed that nested lattice codes can outperform Gaussian codes for this channel when the achieved rate is measured with the weak secrecy notion. Here, with the Renyi entropy and the min entropy measure, we prove that the same secure degree of freedom is achievable with the strong secrecy notion as well. A major benefit of the new coding scheme is that the strong secrecy is generated from a single lattice point instead of a sequence of lattic...

  3. Understanding quantum interference in General Nonlocality

    CERN Document Server

    Wanng, Hai-Jhun

    2010-01-01

    In this paper we attempt to give an understanding of quantum double-slit interference of fermions in the framework of General Nonlocality (GN) [J. Math. Phys. 49, 033513 (2008)] by studying the self-interaction of matter wave. From the metric of the GN, we derive a special formalism to interpret the interference contrast when the self-interaction is perturbative. According to the formalism, the characteristic of interference pattern is in agreement with experiment qualitatively. As examples, we apply the formalism to the cases governed by Schr\\"odinger current and Dirac current respectively, both of which are relevant to topology. The gap between these two cases corresponds to a spin-current effect, which is possible to test in the near future. In addition, a general interference formalism for both perturbative and non-perturbative self-interactions is presented. By analyzing the general formalism we predict that in the nonperturbative limit there is no interference at all.

  4. Phonon-Mediated Nonclassical Interference in Diamond

    Science.gov (United States)

    England, Duncan G.; Fisher, Kent A. G.; MacLean, Jean-Philippe W.; Bustard, Philip J.; Heshami, Khabat; Resch, Kevin J.; Sussman, Benjamin J.

    2016-08-01

    Quantum interference of single photons is a fundamental aspect of many photonic quantum processing and communication protocols. Interference requires that the multiple pathways through an interferometer be temporally indistinguishable to within the coherence time of the photon. In this Letter, we use a diamond quantum memory to demonstrate interference between quantum pathways, initially temporally separated by many multiples of the optical coherence time. The quantum memory can be viewed as a light-matter beam splitter, mapping a THz-bandwidth single photon to a variable superposition of the output optical mode and stored phononic mode. Because the memory acts both as a beam splitter and as a buffer, the relevant coherence time for interference is not that of the photon, but rather that of the memory. We use this mechanism to demonstrate nonclassical single-photon and two-photon interference between quantum pathways initially separated by several picoseconds, even though the duration of the photons themselves is just ˜250 fs .

  5. Interference Alignment for Clustered Multicell Joint Decoding

    CERN Document Server

    Chatzinotas, Symeon

    2010-01-01

    Multicell joint processing has been proven to be very efficient in overcoming the interference-limited nature of the cellular paradigm. However, for reasons of practical implementation global multicell joint decoding is not feasible and thus clusters of cooperating Base Stations have to be considered. In this context, intercluster interference has to be mitigated in order to harvest the full potential of multicell joint processing. In this paper, four scenarios of intercluster interference are investigated, namely a) global multicell joint processing, b) interference alignment, c) resource division multiple access and d) cochannel interference allowance. Each scenario is modelled and analyzed using the per-cell ergodic sum-rate capacity as a figure of merit. In this process, a number of theorems are derived for analytically expressing the asymptotic eigenvalue distributions of the channel covariance matrices. The analysis is based on principles from Free Probability theory and especially properties in the R a...

  6. Laser self-mixing interference fiber sensor

    Institute of Scientific and Technical Information of China (English)

    Zhu Jun; Zhao Yan; Jin Guo-fan

    2008-01-01

    Fibre sensors exhibit a number of advantages over other sensors such as high sensitivity, electric insulation, corrosion resistance, interference rejection and so on. And laser elf-mixing interference can accurately detect the phase difference of feedback light. In this paper, a novel laser self-mixing interference fibre sensor that combines the advantages of fibre sensors with those of laser self-mixing interference is presented. Experimental configurations are set up to study the relationship between laser power output and phase of laser feedback light when the fibre trembles or when the fibre is stretched or pressed. The theoretical analysis of pressure sensors based on laser self-mixing interference is indicated to accord with the experimental results.

  7. Atmospheric Refraction

    CERN Document Server

    Nauenberg, Michael

    2016-01-01

    Calculations of atmospheric refraction are generally based on a simplified model of atmospheric density in the troposphere which assumes that the temperature decreases at a constant lapse rate from sea level up to a height equal to eleven km, and that afterwards it remains constant. In this model, the temperature divided by the lapse rate determines the length scale in the calculations for altitudes less than this height. But daily balloon measurements across the U.S.A. reveal that in some cases the air temperature actually increases from sea level up to a height of about one km, and only after reaching a plateau, it decreases at an approximately constant lapse rate. Moreover, in three examples considered here, the temperature does not remain constant at eleven km , but continues to decreases to a minimum at about sixteen kilometers , and then increases at higher altitudes at a lower rate. Calculations of atmospheric refraction based on this atmospheric data is compared with the results of simplified models.

  8. Atmospheric Dispositifs

    DEFF Research Database (Denmark)

    Wieczorek, Izabela

    2015-01-01

    as a spatial phenomenon, exploring a multiplicity of conditions that constitute their resonant origins – i.e. the production sites from and within they have emerged. The intention is also to argue that despite the fact that atmosphere as an aesthetic category has crystallised over the last few decades...

  9. Applying contextual interference to the Pawlata roll.

    Science.gov (United States)

    Smith, P J; Davies, M

    1995-12-01

    Contextual interference is manipulated by changing the practice order of a number of similar motor tasks, so that the learning context of each interferes with that of the other. The effect has been found to generalize to baseball batting, badminton serving and volleyball skills. The present study examined whether this practice technique could be applied to a Pawlata roll in a kayak. The study was further motivated by the fact that many instructors in Britain currently advocate learning the Pawlata roll in one direction only to a criterion of accuracy, thereafter transferring to the opposite direction. Contextual interference literature predicts that skill retention would be better served by practising on alternate sides. Accordingly, 16 undergraduate students with no kayaking experience were randomly allocated to either a low contextual interference group, which followed U'ren's (1993) recommendations, or a high contextual interference group, which practised the skill on alternate sides. The high contextual interference group took less time to acquire the skill, and were also quicker to achieve successful performance in retention (full roll) and transfer (half roll) tests, regardless of the direction of the roll, 1 week later. The time savings in practice were not expected, as acquisition under high contextual interference was improved rather than impaired. This finding suggests that bilateral transfer was increased by randomizing practice. These results are worthy of further investigation, in that they suggest that the recommended training methods may not be optimal. PMID:8850571

  10. Multiple Beam Interference in a Relativistic Medium

    CERN Document Server

    Rakshit, Supantho

    2016-01-01

    In this paper the effects of movement of optical medium on the conditions of interference, transmission pattern and performance of spectroscopes like Febry Perot are investigated. Firstly, the conditions of constructive and destructive interference of two beams in a moving thin film is derived. Then the idea is expanded to multiple beam interference and a new modified equation of the transmission pattern is formulated with the help of basic Lorentz transformation of space and time co-ordinates and electromagnetic field. Further the new effective resolving power of a Febry Perot spectroscope is determined using this idea, which has a moving dielectric medium in its etalon.

  11. Inter-WBAN Coexistence and Interference Mitigation

    Institute of Scientific and Technical Information of China (English)

    Bin Liu; Xiaosong Zhao; Lei Zou; Chang Wen Chen

    2015-01-01

    With promising applications in e⁃health and entertainment, wireless body area networks (WBANs) have attracted the in⁃terest of both academia and industry. If WBANs are densely deployed within a small area, serious problems may arise be⁃tween the WBANs. In this paper, we discuss issues related to the coexistence of WBANs and investigate the main fac⁃tors that cause inter⁃WBAN interference. We survey inter⁃WBAN interference mitigation strategies and track recent re⁃search developments. We also discuss unresolved issues re⁃lated to inter⁃WBAN interference mitigation and propose fu⁃ture research directions.

  12. Sub-wavelength interference in macroscopic observation

    International Nuclear Information System (INIS)

    We study the generalized Young's double-slit interference for the beam produced in the spontaneous parametric down-conversion (SPDC). It has been found that the sub-wavelength interference can occur macroscopically in both the two-photon intensity measurement and the single-photon spatial intensity-correlation measurement. The former refers to the quantum entanglement and the latter originates from the thermal spatial correlation. We show the visibility and the strength of the interference fringe related to the SPDC interaction, which may provide a strong sub-wavelength lithography with a moderate visibility in practical application

  13. Gas Interference in Sucker Rod Pump

    Science.gov (United States)

    Samad, Abdus

    2010-10-01

    Commonly used artificial lift or dewatering system is sucker rod pump and gas interference of the pump is the biggest issue in the oil and gas industry. Gas lock or fluid pound problems occur due to the gas interference when the pump has partially or completely unfilled plunger barrel. There are several techniques available in the form of patents to solve these problems but those techniques have positive as well as negative aspects. Some of the designs rely on the leakage and some of the designs rely on the mechanical arrangements etc to break the gas lock. The present article compares the existing gas interference handling techniques.

  14. Interference of Fano-Rashba conductance dips

    International Nuclear Information System (INIS)

    We study the interference of two tunable Rashba regions in a quantum wire with one propagating mode. The transmission dips (Fano-Rashba dips) of the two regions either cross or anti-cross, depending on the distance between the two regions. For large separations we find Fabry-Perot oscillations due to the interference of forwards and backwards propagating modes. At small separations overlapping evanescent modes play a prominent role, leading to an enhanced transmission and destroying the conductance dip. Analytical expressions in scattering matrix theory are given and the relevance of the interference effect in a device is discussed.

  15. Wave and Particle in Molecular Interference Lithography

    CERN Document Server

    Juffmann, Thomas; Geyer, Philipp; Major, Andras G; Deachapunya, Sarayut; Ulbricht, Hendrik; Arndt, Markus; 10.1103/PhysRevLett.103.263601

    2010-01-01

    The wave-particle duality of massive objects is a cornerstone of quantum physics and a key property of many modern tools such as electron microscopy, neutron diffraction or atom interferometry. Here we report on the first experimental demonstration of quantum interference lithography with complex molecules. Molecular matter-wave interference patterns are deposited onto a reconstructed Si(111) 7x7 surface and imaged using scanning tunneling microscopy. Thereby both the particle and the quantum wave character of the molecules can be visualized in one and the same image. This new approach to nanolithography therefore also represents a sensitive new detection scheme for quantum interference experiments.

  16. CORRELATED INTERFERENCE CANCELLATION FOR IR-UWB

    Institute of Scientific and Technical Information of China (English)

    Zhang Zaichen; Yu Xutao; Bi Guangguo

    2008-01-01

    In this letter,we propose a hybrid analog/digital detection algorithm,the Correlated Interference Cancellation (CIC) algorithm,for Impulse Radio Ultra-WideBand (IR-UWB) system. The CIC algorithm correlates received signal with its delayed versions in the analog domain and samples the correlation output at the symbol rate. The symbol rate samples are processed in the digital domain to perform interference cancellation. Therefore,CIC works for high data rate systems with heavy InterSymbol Interference (ISI). Simulation results show that CIC achieves good performance in typical UWB channels.

  17. 47 CFR 78.106 - Interference to geostationary-satellites.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Interference to geostationary-satellites. 78... SERVICES CABLE TELEVISION RELAY SERVICE Technical Regulations § 78.106 Interference to geostationary... interference to geostationary-satellites....

  18. Interference Channels with One Cognitive Transmitter

    CERN Document Server

    Cao, Yi

    2009-01-01

    This paper studies the problem of interference channels with one cognitive transmitter (ICOCT) where "cognitive" is defined from both the noncausal and causal perspectives. For the noncausal ICOCT, referred to as interference channels with degraded message sets (IC-DMS), we propose a new achievable rate region that generalizes existing achievable rate regions for IC-DMS. In the absence of the noncognitive transmitter, the proposed region coincides with Marton's region for the broadcast channel. Based on this result, the capacity region of a class of semi-deterministic IC-DMS is established. For the causal ICOCT, due to the complexity of the channel model, we focus primarily on the cognitive Z interference channel (ZIC), where the interference link from the cognitive transmitter to the primary receiver is assumed to be absent due to practical design considerations. Capacity bounds for such channels in different parameter regimes are obtained and the impact of such causal cognitive ability is carefully studied....

  19. Exploiting Genetic Interference for Antiviral Therapy.

    Science.gov (United States)

    Tanner, Elizabeth J; Kirkegaard, Karla A; Weinberger, Leor S

    2016-05-01

    Rapidly evolving viruses are a major threat to human health. Such viruses are often highly pathogenic (e.g., influenza virus, HIV, Ebola virus) and routinely circumvent therapeutic intervention through mutational escape. Error-prone genome replication generates heterogeneous viral populations that rapidly adapt to new selection pressures, leading to resistance that emerges with treatment. However, population heterogeneity bears a cost: when multiple viral variants replicate within a cell, they can potentially interfere with each other, lowering viral fitness. This genetic interference can be exploited for antiviral strategies, either by taking advantage of a virus's inherent genetic diversity or through generating de novo interference by engineering a competing genome. Here, we discuss two such antiviral strategies, dominant drug targeting and therapeutic interfering particles. Both strategies harness the power of genetic interference to surmount two particularly vexing obstacles-the evolution of drug resistance and targeting therapy to high-risk populations-both of which impede treatment in resource-poor settings.

  20. Resolving Business Process Interference via Dynamic Reconfiguration

    NARCIS (Netherlands)

    van Beest, Nick R. T. P.; Bulanov, Pavel; Wortmann, Hans; Lazovik, Alexander; Maglio, PP; Weske, M; Yang, J; Fantinato, M

    2010-01-01

    For business processes supported by service-oriented information systems, concurrent execution of business processes still may yield undesired business outcomes as a result of process interference. For instance, concurrent processes may partially depend on a semantically identical process variable,

  1. Fight plant pests using RNA interference

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ CAS plant physiologists have recently invented a plant-mediated RNA interference (RNAi) technique to effectively and specifically control the gene expression of the cotton bollworm (Helicoverpa armigera) and stunt its growth.

  2. Signal interference RF photonic bandstop filter.

    Science.gov (United States)

    Aryanfar, Iman; Choudhary, Amol; Shahnia, Shayan; Pagani, Mattia; Liu, Yang; Marpaung, David; Eggleton, Benjamin J

    2016-06-27

    In the microwave domain, signal interference bandstop filters with high extinction and wide stopbands are achieved through destructive interference of two signals. Implementation of this filtering concept using RF photonics will lead to unique filters with high performance, enhanced tuning range and reconfigurability. Here we demonstrate an RF photonic signal interference filter, achieved through the combination of precise synthesis of stimulated Brillouin scattering (SBS) loss with advanced phase and amplitude tailoring of RF modulation sidebands. We achieve a square-shaped, 20-dB extinction RF photonic filter over a tunable bandwidth of up to 1 GHz with a central frequency tuning range of 16 GHz using a low SBS loss of ~3 dB. Wideband destructive interference in this novel filter leads to the decoupling of the filter suppression from its bandwidth and shape factor. This allows the creation of a filter with all-optimized qualities. PMID:27410650

  3. Radio VLBI and the quantum interference paradox

    CERN Document Server

    Singal, Ashok K

    2016-01-01

    We address here the question of interference of radio signals from astronomical sources like distant quasars, in a very long baseline interferometer (VLBI), where two (or more) distantly located radio telescopes (apertures), receive simultaneous signal from the sky. In an equivalent optical two-slit experiment, it is generally argued that for the photons involved in the interference pattern on the screen, it is not possible, even in principle, to ascertain which of the two slits a particular photon went through. It is argued that any procedure to ascertain this destroys the interference pattern. But in the case of the modern radio VLBI, it is a routine matter to record the phase and amplitude of the voltage outputs from the two radio antennas on a recording media separately and then do the correlation between the two recorded signals later in an offline manner. Does this not violate the quantum interference principle? We provide a resolution of this problem here.

  4. MIMO Networks: the Effects of Interference

    CERN Document Server

    Chiani, Marco; Shin, Hyundong

    2008-01-01

    Multiple-input/multiple-output (MIMO) systems promise enormous capacity increase and are being considered as one of the key technologies for future wireless networks. However, the decrease in capacity due to the presence of interferers in MIMO networks is not well understood. In this paper, we develop an analytical framework to characterize the capacity of MIMO communication systems in the presence of multiple MIMO co-channel interferers and noise. We consider the situation in which transmitters have no information about the channel and all links undergo Rayleigh fading. We first generalize the known determinant representation of hypergeometric functions with matrix arguments to the case when the argument matrices have eigenvalues of arbitrary multiplicity. This enables the derivation of the ergodic capacity expressions for MIMO systems in the presence of multiple MIMO interferers. Our analysis is valid for any number of interferers, each with arbitrary number of antennas having possibly unequal power levels....

  5. Visual Working Memory Capacity and Proactive Interference

    OpenAIRE

    Hartshorne, Joshua K.

    2008-01-01

    BACKGROUND: Visual working memory capacity is extremely limited and appears to be relatively immune to practice effects or the use of explicit strategies. The recent discovery that visual working memory tasks, like verbal working memory tasks, are subject to proactive interference, coupled with the fact that typical visual working memory tasks are particularly conducive to proactive interference, suggests that visual working memory capacity may be systematically under-estimated. METHODOLOGY/P...

  6. Quantified Interference for a While Language

    OpenAIRE

    Clark, D. (David); Hunt, S.; Malacaria, P.

    2005-01-01

    We show how information theory can be used to give a quantitative definition of interference between variables in imperative programming languages. In this paper we focus on a particular case of this definition of interference: leakage of information from private variables to public ones in While language programs. The major result of the paper is a quantitative analysis for this language that employs a use-definition graph to calculate bounds on the leakage into each variable.

  7. Ordered nanostructures written directly by laser interference

    Energy Technology Data Exchange (ETDEWEB)

    Tan, C; Peng, C S; Pakarinen, J; Pessa, M [Optoelectronics Research Centre, Tampere University of Technology, PO Box 692, 33101 Tampere (Finland); Petryakov, V N; Verevkin, Yu K [The Institute of Applied Physics, 46 Ul' yanova Street, 603600 Nizhny Novgorod (Russian Federation); Zhang, J; Wang, Z [Manufacturing Engineering Centre, Cardiff University, Queen' s Buildings, The Parade, Newport Road, Cardiff CF24 3AA (United Kingdom); Olaizola, S M [CEIT and TECNUN, Paseo Manuel Lardizabal 15, 20018, San Sebastian (Spain); Berthou, T; Tisserand, S [SILIOS Technologies SA, Rue Gaston Imbert prolongee 13 790 Peynier (France)], E-mail: chunlei.tan@tut.fi

    2009-03-25

    We present a simplified method to employ laser interference lithography for the fabrication of ordered nanostructures. Neither resist, nor an elaborate fabrication process was needed. Four-beam interference patterns generated in this work included periodic arrays of holes in GaAs, covered with SiO{sub 2} bubbles, and they were directly written into the sample. The diameters of the smallest holes were less than 30 nm. We propose a model to interpret the results.

  8. Investigation of Interference Models for RFID Systems

    Directory of Open Access Journals (Sweden)

    Linchao Zhang

    2016-02-01

    Full Text Available The reader-to-reader collision in an RFID system is a challenging problem for communications technology. In order to model the interference between RFID readers, different interference models have been proposed, mainly based on two approaches: single and additive interference. The former only considers the interference from one reader within a certain range, whereas the latter takes into account the sum of all of the simultaneous interferences in order to emulate a more realistic behavior. Although the difference between the two approaches has been theoretically analyzed in previous research, their effects on the estimated performance of the reader-to-reader anti-collision protocols have not yet been investigated. In this paper, the influence of the interference model on the anti-collision protocols is studied by simulating a representative state-of-the-art protocol. The results presented in this paper highlight that the use of additive models, although more computationally intensive, is mandatory to improve the performance of anti-collision protocols.

  9. Investigation of Interference Models for RFID Systems.

    Science.gov (United States)

    Zhang, Linchao; Ferrero, Renato; Gandino, Filippo; Rebaudengo, Maurizio

    2016-01-01

    The reader-to-reader collision in an RFID system is a challenging problem for communications technology. In order to model the interference between RFID readers, different interference models have been proposed, mainly based on two approaches: single and additive interference. The former only considers the interference from one reader within a certain range, whereas the latter takes into account the sum of all of the simultaneous interferences in order to emulate a more realistic behavior. Although the difference between the two approaches has been theoretically analyzed in previous research, their effects on the estimated performance of the reader-to-reader anti-collision protocols have not yet been investigated. In this paper, the influence of the interference model on the anti-collision protocols is studied by simulating a representative state-of-the-art protocol. The results presented in this paper highlight that the use of additive models, although more computationally intensive, is mandatory to improve the performance of anti-collision protocols. PMID:26861326

  10. Cross-limb interference during motor learning.

    Directory of Open Access Journals (Sweden)

    Benedikt Lauber

    Full Text Available It is well known that following skill learning, improvements in motor performance may transfer to the untrained contralateral limb. It is also well known that retention of a newly learned task A can be degraded when learning a competing task B that takes place directly after learning A. Here we investigate if this interference effect can also be observed in the limb contralateral to the trained one. Therefore, five different groups practiced a ballistic finger flexion task followed by an interfering visuomotor accuracy task with the same limb. Performance in the ballistic task was tested before the training, after the training and in an immediate retention test after the practice of the interference task for both the trained and the untrained hand. After training, subjects showed not only significant learning and interference effects for the trained limb but also for the contralateral untrained limb. Importantly, the interference effect in the untrained limb was dependent on the level of skill acquisition in the interfering motor task. These behavioural results of the untrained limb were accompanied by training specific changes in corticospinal excitability, which increased for the hemisphere ipsilateral to the trained hand following ballistic training and decreased during accuracy training of the ipsilateral hand. The results demonstrate that contralateral interference effects may occur, and that interference depends on the level of skill acquisition in the interfering motor task. This finding might be particularly relevant for rehabilitation.

  11. On the Feasibility of Linear Interference Alignment for MIMO Interference Broadcast Channels with Constant Coefficients

    OpenAIRE

    Liu, Tingting; Yang, Chenyang

    2012-01-01

    In this paper, we analyze the feasibility of linear interference alignment (IA) for multi-input-multi-output (MIMO) interference broadcast channel (MIMO-IBC) with constant coefficients. We pose and prove the necessary conditions of linear IA feasibility for general MIMO-IBC. Except for the proper condition, we find another necessary condition to ensure a kind of irreducible interference to be eliminated. We then prove the necessary and sufficient conditions for a special class of MIMO-IBC, wh...

  12. Outage analysis of interference-limited systems using STBC with co-channel MIMO interferers

    Institute of Scientific and Technical Information of China (English)

    Yongzhao LI; Leonard J.CIMINI,JR.; Nageen HIMAYAT

    2009-01-01

    The performance of Space-Time Block Coding (STBC) with co-channel MIMO interference is investigated.For an interference-limited environment, the closed-form ex-pressions for the probability density functions of the signal-to-interference ratio are derived and applied to analyze the outage probability with three typical types of co-channel MIMO interferers: STBC, open-loop spatial multiplexing and closed-loop spatial multiplexing. Both theoretical anal-yses and simulation results show that the performance of STBC is independent of the MIMO modes used in the in-terfering links.

  13. Polarized line transfer with F-state interference in a non-magnetic medium: Partial frequency redistribution effects in the collisionless regime

    CERN Document Server

    Smitha, H N; Nagendra, K N; Sampoorna, M; Stenflo, J O

    2012-01-01

    Quantum interference phenomena manifests itself in several ways in the polarized solar spectrum formed due to coherent scattering processes. One such effect arises due to interference between the fine structure (J) states giving rise to multiplets. Another effect is that which arises due to interference between the hyperfine structure (F) states. We extend the redistribution matrix derived for the J-state interference to the case of F-state interference. We then incorporate it into the polarized radiative transfer equation and solve it for isothermal constant property slab atmospheres. The relevant transfer equation is solved using a polarized approximate lambda iteration (PALI) technique based on operator perturbation. An alternative method derived from the Neumann series expansion is also proposed and is found to be relatively more efficient than the PALI method. The effects of PRD and the F-state interference on the shapes of the linearly polarized Stokes profiles are discussed. The emergent Stokes profile...

  14. Planning projects for generation of electrical energy in the state of Sao Paulo, according to the degree of interference on air quality: an atmospheric qualification index using fuzzy sets; Ordenamento de projetos de geracao de energia eletrica no estado de Sao Paulo, segundo o grau de interferencia na qualidade do ar: um indice de qualificacao atmosferica (IQA) utilizando fuzzy sets

    Energy Technology Data Exchange (ETDEWEB)

    Dzedzej, Maira; Maciel, Jonas Fernandes; Santos, Afonso Henrique Moreira [IX Consultoria e Representacoes Ltda, Itajuba, MG (Brazil); Duarte, Pamella Santos [MS Consultoria Ltda, Itajuba, MG (Brazil); Universidade Federal de Itajuba (UNIFEI), MG (Brazil)

    2010-07-01

    Environmental issues are of great importance when assessing the feasibility and priority installation of new developments in electric power generation. In this sense, fuzzy logic can help define the regions that have favorable characteristics for receiving certain forms of generation. This study sought to order for the State of Sao Paulo, four kinds of generation projects: those using municipal solid waste gasification, those which make use of landfill gas with a change in firing (to reduce emissions), thermoelectric plants (TEPs) to bagasse (with 15% straw) and Small Hydropower (SHP). Such an ordering considered not only the type of generation but also the allocation of projects in the four regions, defined by regional vocations as defined by the State Water Resources Plan (Annex III of the State Law No. 9.034/94): Agriculture, Conservation, In Industrialization and Industrial. As a result, the use of fuzzy sets allowed the creation of a ranking of the alternatives (which totaled 14 possibilities), based exclusively on the degree of interference in air quality resulting from the installation of every form of generation. Such information may help the decision-making governing bodies to establish priorities in order, thereby accelerating the process of installation and operation of projects for generating electricity. (author)

  15. Effect of the atmosphere on the classification of LANDSAT data. [Identifying sugar canes in Brazil

    Science.gov (United States)

    Dejesusparada, N. (Principal Investigator); Morimoto, T.; Kumar, R.; Molion, L. C. B.

    1979-01-01

    The author has identified the following significant results. In conjunction with Turner's model for the correction of satellite data for atmospheric interference, the LOWTRAN-3 computer was used to calculate the atmospheric interference. Use of the program improved the contrast between different natural targets in the MSS LANDSAT data of Brasilia, Brazil. The classification accuracy of sugar canes was improved by about 9% in the multispectral data of Ribeirao Preto, Sao Paulo.

  16. Airborne Remote Observations of L-Band Radio Frequency Interference and Implications for Satellite Missions

    Science.gov (United States)

    Laymon, Charles; Srinivasan, Karthik; Limaye, Ashutosh

    2011-01-01

    Passive remote sensing of the Earth s surface and atmosphere from space has significant importance in operational and research environmental studies, in particular for the scientific understanding, monitoring and prediction of climate change and its impacts. Passive remote sensing requires the measurement of naturally occurring radiations, usually of very low power levels, which contain essential information on the physical process under investigation. As such, these sensed radio frequency bands are a unique natural resource enabling space borne passive sensing of the atmosphere and the Earth s surface that deserves adequate allocation to the Earth Exploration Satellite Service and absolute protection from interference. Unfortunately, radio frequency interference (RFI) is an increasing problem for Earth remote sensing, particularly for passive observations of natural emissions. Because these natural signals tend to be very weak, even low levels of interference received by a passive sensor may degrade the fidelity of scientific data. The characteristics of RFI (low-level interference and radar-pulse noise) are not well known because there has been no systematic surveillance, spectrum inventory or mapping of RFI. While conducting a flight experiment over central Tennessee in May 2010, RFI, a concern for any instrument operating in the passive L band frequency, was observed across 16 subbands between 1402-1427 MHz. Such a survey provides rare characterization data from which to further develop mitigation technologies as well as to identify bandwidths to avoid in future sensor formulation.

  17. Remote sensing of nearshore wave interference

    Science.gov (United States)

    Smit, P. B.; Bland, R.; Janssen, T. T.; Laughlin, B.

    2016-05-01

    Wave focusing of energetic swell fields can result in small-scale variations associated with coherent interference that can be important for nearshore circulation and beach dynamics. However, coherent interference is difficult to measure with conventional in situ instruments and is not accounted for in operational wave models. As a result, such effects are generally ignored. In this work, we analyze X-band radar observations collected at Ocean Beach, San Francisco using a Wigner-Ville or coupled-mode spectrum, to show how long-dwell remote sensing technology allows us to identify coherent wave interference. Our analysis demonstrates that during energetic swell events, the nearshore wave field consists of two noncollinear, but coherent, swell patterns that originate from the same offshore source but are directionally separated due to refraction over the San Francisco Bar. The length scale of the associated alongshore wave height variability (200 m) is consistent with the wavenumber separation obtained from the coupled mode analysis. This confirms that the small-scale variability is primarily due to coherent interference. In addition, our analysis shows that the shoreline exhibits a strong localized response near the radar site on the 200 m scale, which suggests that coherent interference effects can affect wave-driven nearshore transport processes and localized erosion.

  18. Epulis and pyogenic granuloma with occlusal interference

    Directory of Open Access Journals (Sweden)

    Widowati Witjaksono

    2005-06-01

    Full Text Available In dental clinic of Hospital University Science Malaysia (HUSM, there were cases with Localized Gingival Enlargement (LGE in the oral cavity with occlusal interference. In this study, three cases were observed. They were a 13 - year- old female with fibrous lge around 31 and 32 with occlusal interference in protrusive movement due to X bite, a 15 - year – old female with pyogenic granuloma near 11 & 21 with occlusal interference due to deep bite; and a 24 – year – old female who was eight months in pregnancy with pyogenic granuloma on the 34-35 and severe generalized pregnancy gingivitis with occlusal interference in centric occlusion and lateral movement. Clinical and histopathological diagnosis of the first case showed fibrous epulis, whereas the second and third cases disclosed pyogenic granuloma. Chronic trauma of the gingiva due to occlusal interference was assumed to be the cause of those LGE in case 1 and 2, while in case 3 poor oral hygiene and chronic trauma were assumed to be the etiologic factors.

  19. General Quantum Interference Principle and Duality Computer

    Institute of Scientific and Technical Information of China (English)

    LONG Gui-Lu

    2006-01-01

    In this article, we propose a general principle of quantum interference for quantum system, and based on this we propose a new type of computing machine, the duality computer, that may outperform in principle both classical computer and the quantum computer. According to the general principle of quantum interference, the very essence of quantum interference is the interference of thesub-waves of the quantum system itself. A quantum system considered here can be any quantum system: a single microscopic particle, a composite quantum system such as an atom or a molecule, or a loose collection of a few quantum objects such as two independent photons. In the duality computer,the wave of the duality computer is split into several sub-waves and they pass through different routes, where different computing gate operations are performed. These sub-waves are then re-combined to interfere to give the computational results. The quantum computer, however, has only used the particle nature of quantum object. In a duality computer,it may be possible to find a marked item from an unsorted database using only a single query, and all NP-complete problems may have polynomial algorithms. Two proof-of-the-principle designs of the duality computer are presented:the giant molecule scheme and the nonlinear quantum optics scheme. We also propose thought experiment to check the related fundamental issues, the measurement efficiency of a partial wave function.

  20. Delaying Interference Training Has Equivalent Effects in Various Pavlovian Interference Paradigms

    Science.gov (United States)

    Powell, Elizabeth J.; Escobar, Martha; Kimble, Whitney

    2013-01-01

    Spontaneous recovery in extinction appears to be inversely related to the acquisition-to-extinction interval, but it remains unclear why this is the case. Rat subjects trained with one of three interference paradigms exhibited less spontaneous recovery of the original response after delayed than immediate interference, regardless of whether…

  1. Analysing Self Interference Cancellation in Full Duplex Radios

    DEFF Research Database (Denmark)

    Mahmood, Nurul Huda; Shafique Ansari, Imran; Berardinelli, Gilberto;

    2016-01-01

    interference power is modelled as a noise-like constant level interference floor. However, experimental validations have shown that the self interference power is in practice a random variable depending on a number of factors such as the surrounding wireless environment and the degree of interference...

  2. Reading Ability Is Negatively Related to Stroop Interference

    Science.gov (United States)

    Protopapas, Athanassios; Archonti, Anastasia; Skaloumbakas, Christos

    2007-01-01

    Stroop interference is often taken as evidence for reading automaticity even though young and poor readers, who presumably lack reading automaticity, present strong interference. Here the relationship between reading skills and Stroop interference was studied in a 7th-grade sample. Greater interference was observed in children diagnosed with…

  3. Testing the Susceptibility of GNSS Receivers to Radio Frequency Interference

    Science.gov (United States)

    Berglund, H. T.; Blume, F.; Gallaher, W. W.

    2015-12-01

    Global Navigational Satellite Systems (GNSS) receivers are employed by the scientific community for measuring a variety of geodetic, geophysical and atmospheric phenomena. Data acquisition frequently occurs in a variety of challenging environments, which include locations with high Radio Frequency (RF) noise characteristics. Tracking the relatively low powered GNSS carrier signals broadcast from space becomes even more challenging in the presence of adjacent band RF noise. The demand for terrestrial RF spectrum use for a variety of non-GNSS applications is ever increasing, which poses potential challenges for GNSS site operators who would like to acquire the highest quality data possible. In recent years, UNAVCO has observed an increase in the number of GNSS sites which are negatively impacted by RF interference. In previous work, we have shown that telemetry systems utilizing the Iridium satellite constellation can degrade GNSS data quality, as the adjacent-band (1610-1616 Mhz) signals transmitted by Iridium data transmitters are close in proximity to the L1 frequency of GNSS. The impact of RF interference from Iridium data transmitters on GNSS receivers can cause reduced Signal-to-Noise (SNR), increased cycle slips, and in worst case scenarios, prevent the receiver from tracking. To better characterize GNSS receiver susceptibility to RF interference, UNAVCO has performed a variety of tests with Continuous Wave (CW) noise sources in RF bands adjacent to the GNSS spectrum. We simulate a subset of discrete noise frequencies commonly observed in the field using a frequency generator, which supplies a signal with varying power output from a transmitter located within 1 m of the GNSS antenna. Signal power is incremented in small steps until receiver tracking fails. All receivers are simultaneously evaluated using an 8-way splitter. In addition, we investigate receiver tracking performance with a simulated increase in the RF noise floor. To analyze the results we use

  4. Collisional quantum interference on rotational energy transfer: physical interpretation of the differential interference angle

    Institute of Scientific and Technical Information of China (English)

    Li Yong-Qing; Li Jian; Ma Feng-Cai

    2006-01-01

    Collisional quantum interference (CQI) on the intramolecular rotational energy transfer is observed in an experiment with a static cell, and the integral interference angles are measured. To obtain more accurate information, an experiment with a molecular beam is carried out, and thereby the relationship between the differential interference angle and the scattering angle is obtained. Based on the first-Born approximation of time-dependent perturbation theory,the theoretical model of CQI is developed in an atom-diatom system in the condition of the molecular beam, with the long-range interaction potential taken into account. The method of measuring correctly the differential interference angle is presented. The tendencies of the differential interference angle changing with the impact parameter and relative velocity are discussed. The theoretical model presented here is important for understanding or performing the experiment in the molecular beam.

  5. Non-classical paths in interference experiments

    CERN Document Server

    Sawant, Rahul; Sinha, Aninda; Sinha, Supurna; Sinha, Urbasi

    2014-01-01

    In a double slit interference experiment, the wave function at the screen with both slits open is not exactly equal to the sum of the wave functions with the slits individually open one at a time. The three scenarios represent three different boundary conditions and as such, the superposition principle should not be applicable. However, most well known text books in quantum mechanics implicitly and/or explicitly use this assumption which is only approximately true. In our present study, we have used the Feynman path integral formalism to quantify contributions from non-classical paths in quantum interference experiments which provide a measurable deviation from a naive application of the superposition principle. A direct experimental demonstration for the existence of these non-classical paths is hard. We find that contributions from such paths can be significant and we propose simple three-slit interference experiments to directly confirm their existence.

  6. Nonclassical Paths in Quantum Interference Experiments

    Science.gov (United States)

    Sawant, Rahul; Samuel, Joseph; Sinha, Aninda; Sinha, Supurna; Sinha, Urbasi

    2014-09-01

    In a double slit interference experiment, the wave function at the screen with both slits open is not exactly equal to the sum of the wave functions with the slits individually open one at a time. The three scenarios represent three different boundary conditions and as such, the superposition principle should not be applicable. However, most well-known text books in quantum mechanics implicitly and/or explicitly use this assumption that is only approximately true. In our present study, we have used the Feynman path integral formalism to quantify contributions from nonclassical paths in quantum interference experiments that provide a measurable deviation from a naive application of the superposition principle. A direct experimental demonstration for the existence of these nonclassical paths is difficult to present. We find that contributions from such paths can be significant and we propose simple three-slit interference experiments to directly confirm their existence.

  7. Bargaining and the MISO Interference Channel

    Science.gov (United States)

    Nokleby, Matthew; Swindlehurst, A. Lee

    2009-12-01

    We examine the MISO interference channel under cooperative bargaining theory. Bargaining approaches such as the Nash and Kalai-Smorodinsky solutions have previously been used in wireless networks to strike a balance between max-sum efficiency and max-min equity in users' rates. However, cooperative bargaining for the MISO interference channel has only been studied extensively for the two-user case. We present an algorithm that finds the optimal Kalai-Smorodinsky beamformers for an arbitrary number of users. We also consider joint scheduling and beamformer selection, using gradient ascent to find a stationary point of the Kalai-Smorodinsky objective function. When interference is strong, the flexibility allowed by scheduling compensates for the performance loss due to local optimization. Finally, we explore the benefits of power control, showing that power control provides nontrivial throughput gains when the number of transmitter/receiver pairs is greater than the number of transmit antennas.

  8. Gravitational and rotational effects in quantum interference

    Energy Technology Data Exchange (ETDEWEB)

    Anandan, J.

    1977-03-15

    The phase shift due to gravitation and rotation in the quantum interference of two coherent beams is obtained relativistically and compared with the recent experiment of Colella, Overhauser, and Werner. A general expression relating the quantum phase shift to the transverse acceleration of a classical particle in the plane of interference for an arbitrary interaction with any external field is given. This can serve as a correspondence principle between quantum physics and classical physics. The phase shift due to the coupling of spin to curvature of space-time is deduced and written explicitly for the special case of a Schwarzschild field. The last result implies that a massless spinning particle can have at most two helicity states and its world line in a gravitational field is a null geodesic. Finally, new experiments are proposed to test the effect of rotation on quantum interference and to obtain direct evidence of the equivalence principle in quantum mechanics.

  9. Adaptive interference techniques for mobile antennas

    Science.gov (United States)

    Griffiths, Lloyd J.; Satorius, E.

    1988-05-01

    The results of a study performed to investigate effective, low cost adaptive signal processing techniques for suppressing mutual satellite interference that can arise in a mobile satellite (MSAT) communication system are discussed. The study focused on the use of adaptive sidelobe cancelling as a method to overcome undesired interference caused by a multiplicity of satellite transmissions within the field of view of the ground station. Results are presented which show that the conventional sidelobe canceller produces undesired reduction of the useful signal. This effect is due to the presence of the useful component in the reference antenna element. An alternative structure, the generalized sidelobe canceller (GSC), has been proposed to overcome this difficulty. A preliminary investigation of possible implementations of the GSC was conducted. It was found that at most 8 bits would be required to implement the GSC processor under conditions in which the desired signal-to-interference ratio is 25 dB.

  10. Multichannel interference mitigation methods in radio astronomy

    CERN Document Server

    Leshem, A; Boonstra, A J; Leshem, Amir; Veen, Alle-Jan van der; Boonstra, Albert-Jan

    2000-01-01

    Radio-astronomical observations are increasingly corrupted by RF interference, and online detection and filtering algorithms are becoming essential. To facilitate the introduction of such techniques into radio astronomy, we formulate the astronomical problem in an array signal processing language, and give an introduction to some elementary algorithms from that field. We consider two topics in detail: interference detection by rank estimation of short-term covariance matrices, and spatial filtering by subspace estimation and projection. We discuss experimental data collected at the Westerbork radio telescope, and illustrate the effectiveness of the space-time detection and blanking process on the recovery of a 3C48 absorption line in the presence of GSM mobile telephony interference.

  11. Cross-limb Interference during motor learning

    DEFF Research Database (Denmark)

    Lauber, Benedikt; Jensen, Jesper Lundbye; Keller, Martin;

    2013-01-01

    investigate if this interference effect can also be observed in the limb contralateral to the trained one. Therefore, five different groups practiced a ballistic finger flexion task followed by an interfering visuomotor accuracy task with the same limb. Performance in the ballistic task was tested before......It is well known that following skill learning, improvements in motor performance may transfer to the untrained contralateral limb. It is also well known that retention of a newly learned task A can be degraded when learning a competing task B that takes place directly after learning A. Here we...... to the trained hand following ballistic training and decreased during accuracy training of the ipsilateral hand. The results demonstrate that contralateral interference effects may occur, and that interference depends on the level of skill acquisition in the interfering motor task. This finding might...

  12. Phonon wave interference and thermal bandgap materials.

    Science.gov (United States)

    Maldovan, Martin

    2015-07-01

    Wave interference modifies phonon velocities and density of states, and in doing so creates forbidden energy bandgaps for thermal phonons. Materials that exhibit wave interference effects allow the flow of thermal energy to be manipulated by controlling the material's thermal conductivity or using heat mirrors to reflect thermal vibrations. The technological potential of these materials, such as enhanced thermoelectric energy conversion and improved thermal insulation, has fuelled the search for highly efficient phonon wave interference and thermal bandgap materials. In this Progress Article, we discuss recent developments in the understanding and manipulation of heat transport. We show that the rational design and fabrication of nanostructures provides unprecedented opportunities for creating wave-like behaviour of heat, leading to a fundamentally new approach for manipulating the transfer of thermal energy.

  13. On Interference of Chinese with ELL

    Institute of Scientific and Technical Information of China (English)

    九曼

    2011-01-01

    It is popularly admitted that the foreign language learning is strongly influenced by learners' first language.Generally speaking,the interference of Chinese with ELL is divided into negative transfer and positive transfer,which are manifested at various levels during ELL.The thesis aims to show the interference of Chinese with ELL,with the approach of qualitative analysis,the paper is arranged into Part Ⅰ:Introduction; Part Ⅱ:The Contrast between ELL and Chinese Language Acquisition; Part Ⅲ:The Influence of Chinese on ELL:Part Ⅵ:Conclusion.Being aware of the interference of Chinese with ELL will help students overcome the obstacles and promote ELL.

  14. Time and interference: Effects on working memory.

    Science.gov (United States)

    Botto, Marta; Palladino, Paola

    2016-05-01

    This study tested predictions from the time-based resource-sharing (TBRS) model with a classical verbal working memory (WM) task, where target and non-target information interfere strongly with each other. Different predictions can be formulated according to the dominant perspectives (TBRS and interference hypothesis) on the role of inhibitory control in WM task performance. Here, we aimed to trace the activation of irrelevant information, examining priming effects in a lexical decision task immediately following WM recall. Results indicate the roles of both time and interference constraints in determining task performance. In particular, the role of time available seemed crucial at the highest WM loads (i.e., 3 and 4 memoranda). These were also associated with a higher activation of no-longer-relevant information but, in this case, independently from time available for processing. PMID:26085338

  15. Electromagnetic Interference on Large Wind Turbines

    Directory of Open Access Journals (Sweden)

    Florian Krug

    2009-11-01

    Full Text Available Electromagnetic interference (EMI can both affect and be transmitted by mega-watt wind turbines. This paper provides a general overview on EMI with respect to mega-watt wind turbines. Possibilities of measuring all types of electromagnetic interference are shown. Electromagnetic fields resulting from a GSM transmitter mounted on a mega-watt wind turbine will be analyzed in detail. This cellular system operates as a real-time communication link. The method-of-moments is used to analytically describe the electro-magnetic fields. The electromagnetic interference will be analyzed under the given boundary condition with a commercial simulation tool. Different transmitter positions are judged on the basis of their radiation patterns. The principal EMI mechanisms are described and taken into consideration.

  16. Frequent video game players resist perceptual interference.

    Directory of Open Access Journals (Sweden)

    Aaron V Berard

    Full Text Available Playing certain types of video games for a long time can improve a wide range of mental processes, from visual acuity to cognitive control. Frequent gamers have also displayed generalized improvements in perceptual learning. In the Texture Discrimination Task (TDT, a widely used perceptual learning paradigm, participants report the orientation of a target embedded in a field of lines and demonstrate robust over-night improvement. However, changing the orientation of the background lines midway through TDT training interferes with overnight improvements in overall performance on TDT. Interestingly, prior research has suggested that this effect will not occur if a one-hour break is allowed in between the changes. These results have suggested that after training is over, it may take some time for learning to become stabilized and resilient against interference. Here, we tested whether frequent gamers have faster stabilization of perceptual learning compared to non-gamers and examined the effect of daily video game playing on interference of training of TDT with one background orientation on perceptual learning of TDT with a different background orientation. As a result, we found that non-gamers showed overnight performance improvement only on one background orientation, replicating previous results with the interference in TDT. In contrast, frequent gamers demonstrated overnight improvements in performance with both background orientations, suggesting that they are better able to overcome interference in perceptual learning. This resistance to interference suggests that video game playing not only enhances the amplitude and speed of perceptual learning but also leads to faster and/or more robust stabilization of perceptual learning.

  17. Interference Alignment with Incomplete CSIT Sharing

    OpenAIRE

    De Kerret, Paul; Gesbert, David

    2012-01-01

    In this work, we study the impact of having only incomplete channel state information at the transmitters (CSIT) over the feasibility of interference alignment (IA) in a K-user MIMO interference channel (IC). Incompleteness of CSIT refers to the perfect knowledge at each transmitter (TX) of only a sub-matrix of the global channel matrix, where the sub-matrix is specific to each TX. This paper investigates the notion of IA feasibility for CSIT configurations being as incomplete as possible, as...

  18. Carbon nanostructure composite for electromagnetic interference shielding

    Indian Academy of Sciences (India)

    Anupama Joshi; Suwarna Datar

    2015-06-01

    This communication reviews current developments in carbon nanostructure-based composite materials for electromagnetic interference (EMI) shielding. With more and more electronic gadgets being used at different frequencies, there is a need for shielding them from one another to avoid interference. Conventionally, metal-based shielding materials have been used. But due to the requirement of light weight, corrosion resistive materials, lot of work is being done on composite materials. In this research the forerunner is the nanocarbon-based composite material whose different forms add different characteristics to the composite. The article focusses on composites based on graphene, graphene oxide, carbon nanotubes, and several other novel forms of carbon.

  19. Gathering algorithms on paths under interference constraints

    OpenAIRE

    Bermond, Jean-Claude; Correa, Ricardo; Yu, Min-Li

    2006-01-01

    International audience We study the problem of gathering information from the nodes of a multi-hop radio network into a pre-determined destination node under interference constraints which are modeled by an integer d 1, so that any node within distance d of a sender cannot receive calls from any other sender. A set of calls which do not interfere with each other is referred to as a round. We give algorithms and lower bounds on the minimum number of rounds for this problem, when the network...

  20. Phonon interference effects in molecular junctions

    International Nuclear Information System (INIS)

    We study coherent phonon transport through organic, π-conjugated molecules. Using first principles calculations and Green's function methods, we find that the phonon transmission function in cross-conjugated molecules, like meta-connected benzene, exhibits destructive quantum interference features very analogous to those observed theoretically and experimentally for electron transport in similar molecules. The destructive interference features observed in four different cross-conjugated molecules significantly reduce the thermal conductance with respect to linear conjugated analogues. Such control of the thermal conductance by chemical modifications could be important for thermoelectric applications of molecular junctions

  1. Phonon interference effects in molecular junctions

    Energy Technology Data Exchange (ETDEWEB)

    Markussen, Troels, E-mail: troels.markussen@gmail.com [Center for Atomic-scale Materials Design (CAMD), Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

    2013-12-28

    We study coherent phonon transport through organic, π-conjugated molecules. Using first principles calculations and Green's function methods, we find that the phonon transmission function in cross-conjugated molecules, like meta-connected benzene, exhibits destructive quantum interference features very analogous to those observed theoretically and experimentally for electron transport in similar molecules. The destructive interference features observed in four different cross-conjugated molecules significantly reduce the thermal conductance with respect to linear conjugated analogues. Such control of the thermal conductance by chemical modifications could be important for thermoelectric applications of molecular junctions.

  2. Interference-free ultrasonic level measuring sensor

    International Nuclear Information System (INIS)

    To avoid interference phenomena depending on the level, an ultrasonic level measuring sensor is proposed, which has an envelope tube around the path of the ultrasonic signal to prevent reflection. An ultrasonic transducer suspended by means of a linkage on a flange is additionally provided with a corrugated hose or a sintered metal tube around the path of the ultrasonic signal. A reference element necessary to raise the accuracy can be fitted in a cutout of the envelope tube. This device makes very precise measurement of the level possible without variations in the accuracy of measurement depending on the level, as interference due to shunt reflection is prevented. (orig./HP)

  3. Four-wave interference and perfect blaze.

    Science.gov (United States)

    Güther, R

    2012-10-01

    The recently calculated high diffraction efficiencies for TE- and TM-polarized light (perfect blaze) for echelette gratings are explained by four-wave interference, which is formed as a double periodical pattern in the cross section of the grating plane. The blazed grating profile should match this interference pattern for a single reference light wavelength. The recently published data are the special case of a general design. The prognoses of the model are connected with large grating constants in comparison with the light wavelength, where short grating constants need comparison with numerical methods.

  4. Neutrino tridents and W - Z interference

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, S.R.; Rabinowitz, S.A.; Arroyo, C.; Bachmann, K.T.; Blair, R.E.; Foudas, C.; King, B.J.; Lefmann, W.C.; Leung, W.C.; Oltman, E.; Quintas, P.Z.; Sciulli, F.J.; Seligman, B.G.; Shaevitz, M.H. (Columbia University, New York, New York 10027 (USA)); Merritt, F.S.; Oreglia, M.J.; Schumm, B.A. (University of Chicago, Chicago, Illinois 60637 (USA)); Bernstein, R.H.; Borcherding, F.; Fisk, H.E.; Lamm, M.J.; Marsh, W.; Merritt, K.W.B.; Schellman, H.; Yovanovitch, D.D. (Fermilab, Batavia, Illinois 60510 (USA)); Bodek, A.; Budd, H.S.; de Barbaro, P.; Sakumoto, W.K. (University of Rochester, Rochester, New York 14627 (USA)); Sandler, P.H.; Smith, W.H. (University of Wisconsin, Madison, Wisconsin 53706 (USA))

    1991-06-17

    We present a measurement of neutrino tridents, muon pairs induced by neutrino scattering in the Coulomb field of a target nucleus, in the Columbia-Chicago-Fermilab-Rochester neutrino experiment at the Fermilab Tevatron. The observed number of tridents after geometric and kinematic corrections, 37.0{plus minus}12.4, supports the standard-model prediction of 45.3{plus minus}2.3 events. This is the first demonstration of the {ital W}-{ital Z} destructive interference from neutrino tridents, and rules out, at 99% C.L., the {ital V}-{ital A} prediction without the interference.

  5. Interference of electromagnetic waves in dynamic metabolism

    Institute of Scientific and Technical Information of China (English)

    黄卡玛; 唐敬贤; 刘永清; 徐兰

    1995-01-01

    Life is a continuous process of the dynamic metabolism.The influence of electromagneticwaves on the process of metabolism cannot be neglected.Here a new theory of electromagnetic interference inthe dynamic metabolism of life is proposed.The statistical dynamic equations of ion and free radical in thebiochemical reaction radiated by electromagnetic waves are given.The intensity of electromagnetic interferencecould be described with an interference factor.Good agreement can be seen between the calculated and meas-ured results for a famous experiment of radio-frequency radiation-induced calcium ion efflux enhancement.

  6. Sensorimotor Interference When Reasoning About Described Environments

    Science.gov (United States)

    Avraamides, Marios N.; Kyranidou, Melina-Nicole

    The influence of sensorimotor interference was examined in two experiments that compared pointing with iconic arrows and verbal responding in a task that entailed locating target-objects from imagined perspectives. Participants studied text narratives describing objects at locations around them in a remote environment and then responded to targets from memory. Results revealed only minor differences between the two response modes suggesting that bodily cues do not exert severe detrimental interference on spatial reasoning from imagined perspective when non-immediate described environments are used. The implications of the findings are discussed.

  7. Control of exciton transport using quantum interference

    Science.gov (United States)

    Lusk, Mark T.; Stafford, Charles A.; Zimmerman, Jeramy D.; Carr, Lincoln D.

    2015-12-01

    It is shown that quantum interference can be employed to create an exciton transistor. An applied potential gates the quasiparticle motion and also discriminates between quasiparticles of differing binding energy. When implemented within nanoscale assemblies, such control elements could mediate the flow of energy and information. Quantum interference can also be used to dissociate excitons as an alternative to using heterojunctions. A finite molecular setting is employed to exhibit the underlying discrete, two-particle, mesoscopic analog to Fano antiresonance. Selected entanglement measures are shown to distinguish regimes of behavior which cannot be resolved from population dynamics alone.

  8. Effects of optical interference and annealing on the performance of poly (3-hexylthiophene):fullerene based solar cells

    Institute of Scientific and Technical Information of China (English)

    You Hai-Long; Zhang Chun-Fu

    2009-01-01

    In this paper, the effects of optical interference and annealing on the performance of P3HT:PCBM based organic solar cells are studied in detail. Due to the optical interference effect, short circuit current density (JSC) shows obvious oscillatory behaviour with the variation of active layer thickness. With the help of the simulated results, the devices are optimized around the first two optical interference peaks. It is found that the optimized thicknesses are 80 and 208 nm. The study on the effect of annealing on the performance indicates that post-annealing is more favourable than pre-annealing. Based on post-annealing, different annealing temperatures are tested. The optimized annealing condition is 160℃ for 10 min in a nitrogen atmosphere. The device shows that the open circuit voltage VOC achieves about 0.65V and the power conversion efficiency is as high as 4.0 % around the second interference peak.

  9. Wind interference between two high-rise building models: On the influence of shielding, channeling and buffeting on peak pressures

    NARCIS (Netherlands)

    Bronkhorst, A.J.; Geurts, C.P.W.; Bentum, C.A. van; Blocken, B.

    2014-01-01

    The influence of interference between two high-rise building models on the minimum peak pressures was investigated in an atmospheric boundary layer wind tunnel. Pressure measur€ments were performed on a square model with an aspect ratio of 1 to 4. The influence of an interfering model with the same

  10. Jam-X: Wireless Agreement under Interference

    CERN Document Server

    Boano, Carlo Alberto; Zúñiga, Marco Antonio; Voigt, Thiemo

    2012-01-01

    Wireless low-power transceivers used in sensor networks such as IEEE 802.15.4 typically operate in unlicensed frequency bands that are subject to external interference from devices transmitting at much higher power. Communication protocols should therefore be designed to be robust against such interference. A critical building block of many protocols at all layers is agreement on a piece of information among a set of nodes. At the MAC layer, nodes may need to agree on a new time slot or frequency channel; at the application layer nodes may need to agree on handing over a leader role from one node to another. Message loss caused by interference may break agreement in two different ways: none of the nodes use the new information (time slot, channel, leader) and stick with the previous assignment, or - even worse - some nodes use the new information and some do not. This may lead to reduced performance or failures. In this paper we investigate the problem of agreement under interference and point out the limitat...

  11. 47 CFR 22.353 - Blanketing interference.

    Science.gov (United States)

    2010-10-01

    ... Operational and Technical Requirements Technical Requirements § 22.353 Blanketing interference. Licensees of...: ER17NO94.007 where d is the radial distance to the boundary, in kilometers p is the radial effective radiated power, in kilowatts The maximum effective radiated power in the pertinent direction,...

  12. Movement Interference in Autism-Spectrum Disorder

    Science.gov (United States)

    Gowen, E.; Stanley, J.; Miall, R. C.

    2008-01-01

    Movement interference occurs when concurrently observing and executing incompatible actions and is believed to be due to co-activation of conflicting populations of mirror neurons. It has also been suggested that mirror neurons contribute towards the imitation of observed actions. However, the exact neural substrate of imitation may depend on task…

  13. Interference Fragmentation Functions and the Nucleon's Transversity

    OpenAIRE

    Jaffe, R. L.; Jin, Xuemin; Tang, Jian

    1997-01-01

    We introduce twist-two quark interference fragmentation functions in helicity density matrix formalism and study their physical implications. We show how the nucleon's transversity distribution can be probed through the final state interaction between two mesons ($\\pi^+\\pi^-$, $K\\bar K$, or $\\pi K$) produced in the current fragmentation region in deep inelastic scattering on a transversely polarized nucleon.

  14. Electron Interference in Ballistic Graphene Nanoconstrictions

    DEFF Research Database (Denmark)

    Baringhaus, Jens; Settnes, Mikkel; Aprojanz, Johannes;

    2016-01-01

    We realize nanometer size constrictions in ballistic graphene nanoribbons grown on sidewalls of SiC mesa structures. The high quality of our devices allows the observation of a number of electronic quantum interference phenomena. The transmissions of Fabry-Perot-like resonances are probed...

  15. Stroop interference and disorders of selective attention

    NARCIS (Netherlands)

    Kingma, A.; LaHeij, W.; Fasotti, L.; Eling, P.

    1996-01-01

    Fourteen patients with a right-hemisphere CVA and 8 patients with a left-hemisphere CVA were examined for selective attention deficits using a variant of the Stroop color-word task: the picture-word interference task. Experiments 1 and 2 first compared the performance of the two patient groups and a

  16. On optimization of interference fit assembly

    DEFF Research Database (Denmark)

    Pedersen, Niels Leergaard

    2016-01-01

    Assembly of shaft and hub by an interference fitis a classical connection with known advantages and disadvantages.The advantage being the level of possible torque transfer while the disadvantage is a possible fretting fatigue failure at the points of stress concentration. To improve the assembly ...

  17. Phonon interference effects in molecular junctions

    DEFF Research Database (Denmark)

    Markussen, Troels

    2013-01-01

    We study coherent phonon transport through organic, p-conjugated molecules. Using first principles calculations and Green's function methods, we find that the phonon transmission function in cross-conjugated molecules, like meta-connected benzene, exhibits destructive quantum interference features...

  18. ASYMMETRICAL INTERFERENCE OF COUNTER OBLIQUE SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-09-01

    Full Text Available Subject of Study. The paper deals with data on the interference of shock waves with different intensity and slope angles to the flow of them. This problem is related to the problem of designing air intakes to the internal compression and detonation combustion engines in stationary overdriven detonation wave. A regular form of interference and irregular Mach one are considered. Intensity calculations of reflected shock waves for both cases are given. As shown below, there is a possibility of a very large difference in the intensity of the reflected shocks. Main Results. We describe transition criteria from regular to irregular reflection of counter shocks: von Neumann criterion and a stationary Mach configuration criterion. Intensity dependences of the reflected intensity shocks from the interaction of colliding shock waves are presented both for the case of regular interaction, and irregular interference. We demonstrate intensity dependence of a reflected shock wave on the intensity of the two interacting shock waves, as in the transition from regular to irregular reflection, in accordance with von Neumann detaching criterion, and in accordance with a stationary Mach configuration criterion. In the first case, the transition is accompanied by an abrupt change in the intensity of the reflected shock; in the second case, the intensity varies in a continuous manner. Practical Relevance. The results supplement interference theory of stationary gas-dynamic discontinuities and are usable in the design of advanced air intakes of internal compression supersonic and hypersonic aircrafts.

  19. Exploiting Genetic Interference for Antiviral Therapy.

    Science.gov (United States)

    Tanner, Elizabeth J; Kirkegaard, Karla A; Weinberger, Leor S

    2016-05-01

    Rapidly evolving viruses are a major threat to human health. Such viruses are often highly pathogenic (e.g., influenza virus, HIV, Ebola virus) and routinely circumvent therapeutic intervention through mutational escape. Error-prone genome replication generates heterogeneous viral populations that rapidly adapt to new selection pressures, leading to resistance that emerges with treatment. However, population heterogeneity bears a cost: when multiple viral variants replicate within a cell, they can potentially interfere with each other, lowering viral fitness. This genetic interference can be exploited for antiviral strategies, either by taking advantage of a virus's inherent genetic diversity or through generating de novo interference by engineering a competing genome. Here, we discuss two such antiviral strategies, dominant drug targeting and therapeutic interfering particles. Both strategies harness the power of genetic interference to surmount two particularly vexing obstacles-the evolution of drug resistance and targeting therapy to high-risk populations-both of which impede treatment in resource-poor settings. PMID:27149616

  20. Neutron Interference Experiments and Quantum Measurement Theory

    Science.gov (United States)

    Namiko, M.; Otake, Y.; Soshi, H.

    1987-03-01

    Physical and epistemological implications of recent experiments on the neutron interference are discussed from the viewpoint of the Machida-Namiki theory of measurement in quantum mechanics, without resort to discussion on the number-phase uncertainty relation. The same idea is also applied to the neutrino oscillation problem.

  1. Phase-Modulation Laser Interference Microscopy

    DEFF Research Database (Denmark)

    Brazhe, Alexey; Brazhe, Nadezda; Maximov, G. V.;

    2008-01-01

    We describe how phase-modulation laser interference microscopy and wavelet analysis can be applied to noninvasive nonstained visualization and study of the structural and dynamical properties of living cells. We show how phase images of erythrocytes can reveal the difference between various...

  2. Engine Power Effects on Support Interference

    NARCIS (Netherlands)

    Horsten, B.J.C.; Veldhuis, L.L.M.

    2009-01-01

    Renewed interest in propeller propulsion on aircraft configurations combined with higher propeller loads lead to the question how the effects of the propulsion on model support disturbances should be accounted for. In this paper, the determination of engine power effects on support interference of s

  3. Feshbach Resonance Induced Fano Interference in Photoassociation

    CERN Document Server

    Deb, Bimalendu

    2009-01-01

    We consider photoassociation from a state of two free atoms when the continuum state is close to a magnetic field induced Feshbach resonance and demonstrate the possibility of Fano interference in photoassociation. We introduce an analog of Fano asymmetry parameter which characterizes the minimum in photoassociation profiles. We further show a nonlinear analog of Fano effect, which was recently observed in quantum dots.

  4. Two-order Interference of Single Photon

    Institute of Scientific and Technical Information of China (English)

    JIANG Yunkun; LI Jian; SHI Baosen; FAN Xiaofeng; GUO Guangcan

    2000-01-01

    A pair of photons called signal and idler photons, respectively, are produced through the nonlinear process of type-I spontaneous parametric downconversion in BBO crystal pumped by the second-harmonic wave of a Ti:sapphire femtosecond laser pulse. The two-order interference phenomenon of the signal photon in Michelson interferometer is observed and give an analysis in detail.

  5. Interference effects of categorization on decision making.

    Science.gov (United States)

    Wang, Zheng; Busemeyer, Jerome R

    2016-05-01

    Many decision making tasks in life involve a categorization process, but the effects of categorization on subsequent decision making has rarely been studied. This issue was explored in three experiments (N=721), in which participants were shown a face stimulus on each trial and performed variations of categorization-decision tasks. On C-D trials, they categorized the stimulus and then made an action decision; on X-D trials, they were told the category and then made an action decision; on D-alone trials, they only made an action decision. An interference effect emerged in some of the conditions, such that the probability of an action on the D-alone trials (i.e., when there was no explicit categorization before the decision) differed from the total probability of the same action on the C-D or X-D trials (i.e., when there was explicit categorization before the decision). Interference effects are important because they indicate a violation of the classical law of total probability, which is assumed by many cognitive models. Across all three experiments, a complex pattern of interference effects systematically occurred for different types of stimuli and for different types of categorization-decision tasks. These interference effects present a challenge for traditional cognitive models, such as Markov and signal detection models, but a quantum cognition model, called the belief-action entanglement (BAE) model, predicted that these results could occur. The BAE model employs the quantum principles of superposition and entanglement to explain the psychological mechanisms underlying the puzzling interference effects. The model can be applied to many important and practical categorization-decision situations in life. PMID:26896726

  6. Feedback-Topology Designs for Interference Alignment in MIMO Interference Channels

    CERN Document Server

    Cho, Sungyoon; Huang, Kaibin; Kim, Dongku; Lau, Vincent K N; Seo, Hanbyul; Kim, Byounghoon

    2011-01-01

    Interference alignment (IA) is a joint-transmission technique that achieves the capacity of the interference channel for high signal-to-noise ratios (SNRs). Most prior work on IA is based on the impractical assumption that perfect and global channel-state information(CSI) is available at all transmitters. To implement IA, each receiver has to feed back CSI to all interferers, resulting in overwhelming feedback overhead. In particular, the sum feedback rate of each receiver scales quadratically with the number of users even if the quantized CSI is fed back. To substantially suppress feedback overhead, this paper focuses on designing efficient arrangements of feedback links, called feedback topologies, under the IA constraint. For the multiple-input-multiple-output (MIMO) K-user interference channel, we propose the feedback topology that supports sequential CSI exchange (feedback and feedforward) between transmitters and receivers so as to achieve IA progressively. This feedback topology is shown to reduce the ...

  7. Receive Diversity and Ergodic Performance of Interference Alignment on the MIMO Gaussian Interference Channel

    CERN Document Server

    Guillaud, Maxime

    2010-01-01

    We consider interference alignment (IA) over K-user Gaussian MIMO interference channel (MIMO-IC) when the SNR is not asymptotically high. We introduce a generalization of IA which enables receive diversity inside the interference-free subspace. We generalize the existence criterion of an IA solution proposed by Yetis et al. to this case, thereby establishing a multi-user diversity-multiplexing trade-off (DMT) for the interference channel. Furthermore, we derive a closed-form tight lower-bound for the ergodic mutual information achievable using IA over a Gaussian MIMO-IC with Gaussian i.i.d. channel coefficients at arbitrary SNR, when the transmitted signals are white inside the subspace defined by IA. Finally, as an application of the previous results, we compare the performance achievable by IA at various operating points allowed by the DMT, to a recently introduced distributed method based on game theory.

  8. The differential interference angle in collisional quantum interference on rotational energy transfer

    Institute of Scientific and Technical Information of China (English)

    Wang Wei-Li; Miao Gang; Chen Yue-Hui; Tang Dan; Ma Feng-Cai

    2008-01-01

    Collisional quantum interference (CQI) in the intramolecular rotational energy transfer was observed in experiment by Sha and co-workers.[1] The interference angle, which measuring the degree of the coherence, were measured in the experiment of the static cell. Based on the first Born approximation of time dependent perturbation theory, taking into accounts the anisotropic Lennard-Jones interaction potentials, this paper describes the theoretical model of CQI in intramolecular rotational energy transfer in an atom-diatom collision system. In the model, the differential interference angle for the experiment of the molecular beam is calculated, the changing tendencies of the differential interference angle with the impact parameter and collision partners are obtained. This theoretical model is important for understanding or performing this kind of experiments.

  9. Analysis of optical frequency-modulated continuous-wave interference.

    Science.gov (United States)

    Zheng, Jesse

    2004-07-20

    I systematically analyze the theory of optical frequency-modulated continuous-wave (FMCW) interference. There are three different versions of optical FMCW interference, discussed in detail: sawtooth-wave optical FMCW interference, triangular-wave optical FMCW interference, and sinusoidal-wave optical FMCW interference. The essential concepts and technical terms are clearly defined, the necessary simplifications are introduced according to the characteristics of optical waves, and the formulas used to calculate the signal intensities under two different situations (static and dynamic) are properly derived. Advantages and limitations of each version of optical FMCW interference are also discussed. PMID:15291063

  10. Interference Mitigation by Statistical Interference Modeling in an Impulse Radio UWB Receiver

    OpenAIRE

    Flury, Manuel; Le Boudec, Jean-Yves

    2006-01-01

    Some impulse radio UWB (IR-UWB) networks may allow concurrent transmissions without power control (for example MAC protocols that do not use power control, or co-exisiting, non-coordinated piconets). In such cases, it has been proposed to mitigate multi-user interference (MUI) at the physical layer, but existing proposals for interference mitigation do not account for the multipath nature of UWB channels. We address this problem and propose a receiver that employs a combination of statistical...

  11. Exploiting Spatial Interference Alignment and Opportunistic Scheduling in the Downlink of Interference Limited Systems

    OpenAIRE

    Kuchi, Kiran

    2013-01-01

    In this paper we analyze the performance of single stream and multi-stream spatial multiplexing (SM) systems employing opportunistic scheduling in the presence of interference. In the proposed downlink framework, every active user reports the post-processing signal-to-interference-plus-noise-power-ratio (post-SINR) or the receiver specific mutual information (MI) to its own transmitter using a feedback channel. The combination of scheduling and multi-antenna receiver processing leads to subst...

  12. (Sub-)Optimality of Treating Interference as Noise in the Cellular Uplink With Weak Interference

    KAUST Repository

    Gherekhloo, Soheil

    2015-11-09

    Despite the simplicity of the scheme of treating interference as noise (TIN), it was shown to be sum-capacity optimal in the Gaussian interference channel (IC) with very-weak (noisy) interference. In this paper, the two-user IC is altered by introducing an additional transmitter that wants to communicate with one of the receivers of the IC. The resulting network thus consists of a point-to-point channel interfering with a multiple access channel (MAC) and is denoted by PIMAC. The sum-capacity of the PIMAC is studied with main focus on the optimality of TIN. It turns out that TIN in its naive variant, where all transmitters are active and both receivers use TIN for decoding, is not the best choice for the PIMAC. In fact, a scheme that combines both time division multiple access and TIN (TDMA-TIN) strictly outperforms the naive-TIN scheme. Furthermore, it is shown that in some regimes, TDMA-TIN achieves the sum-capacity for the deterministic PIMAC and the sum-capacity within a constant gap for the Gaussian PIMAC. In addition, it is shown that, even for very-weak interference, there are some regimes where a combination of interference alignment with power control and TIN at the receiver side outperforms TDMA-TIN. As a consequence, on the one hand, TIN in a cellular uplink is approximately optimal in certain regimes. On the other hand, those regimes cannot be simply described by the strength of interference.

  13. The Approximate Capacity Region of the Symmetric $K$-user Gaussian Interference Channel with Strong Interference

    KAUST Repository

    Chaaban, Anas

    2016-03-01

    The symmetric K-user interference channel is studied with the goal of characterizing its capacity region in the strong interference regime within a constant gap. The achievable rate region of a scheme combining rate-splitting at the transmitters and interference alignment and successive decoding/computation at the receivers is derived. Next it is shown that this scheme achieves the so-called greedy-max corner points of the capacity region within a constant gap. By combining this result with previous results by Ordentlich et al. on the sum-capacity of the symmetric interference channel, a constant gap characterization of the capacity region for the strong interference regime is obtained. This leads to the first approximate characterization of the capacity region of the symmetric K-user IC. Furthermore, a new scheme that achieves the sum-capacity of the channel in the strong interference regime within a constant gap is also proposed, and the corresponding gap is calculated. The advantage of the new scheme is that it leads to a characterization within a constant gap without leaving an outage set contrary to the scheme by Ordentlich et al..

  14. Canceling Interference in Acupuncture Points Signal

    Directory of Open Access Journals (Sweden)

    Yanexy San Martín Reyes

    2012-07-01

    Full Text Available The present paper propose the cancellation of interference or artifacts by the method of Allen in signals captured in different acupuncture points (Small Intestine Meridian, points ID1-ID2 and ID1-ID19. It is considered that the biosignal under study should be able to be characterized after its acquisition by subtracting the different interference variables that may coexist in the measurement zone, as it is in the case of ECG or any other artifact. The biosignal obtained as a result of the cancellation will be the acupuncture signal or from its imperfection another wave can be obtained as from a bioelectrical point of view such imperfection can be characterized and at the same time can bb useful to establish a long-term correspondence between the behavior of the signals on various acupuncture points and different diseases.

  15. RNA interference - From Biology to clinical applications

    Directory of Open Access Journals (Sweden)

    CarloAlberto Redi

    2010-12-01

    Full Text Available I strongly advice the readers to go to the Nobel foundation web site and read the Nobel lectures by Andrew Z. Fire and Craig C. Mello, the two 2006 Nobel laureates "for their discovery of RNA interference - gene silencing by double-stranded RNA" (http://nobelprize.org/nobel_prizes/medicine/laureates/2006/. Well, it is impressive how both the Nobel laureates clearly anticipate the immense possibility the phenomenon they discovered is giving to Biology and its applications. That is to say, they clearly visioned the great chance to both advance our theoretical understanding of gene expression regulation (i.e., how the gene networks and circuiteries are finely tuned by RNA interference, and its critical role in ontogeny and make use in biotechnological applications of this formidable tool, notably in translational medicine. Here we go to the............

  16. Parametric constraints in multi-beam interference

    Science.gov (United States)

    Burrow, Guy M.; Gaylord, Thomas K.

    2012-10-01

    Multi-beam interference (MBI) represents a method of producing one-, two-, and three-dimensional submicron periodic optical-intensity distributions for applications including micro- and nano-electronics, photonic crystals, metamaterial, biomedical structures, optical trapping, and numerous other subwavelength structures. Accordingly, numerous optical configurations have been developed to implement MBI. However, these configurations typically provide limited ability to condition the key parameters of each interfering beam. Constraints on individual beam amplitudes and polarizations are systematically considered to understand their effects on lithographically useful MBI periodic patterning possibilities. A method for analyzing parametric constraints is presented and used to compare the optimized optical-intensity distributions for representative constrained systems. Case studies are presented for both square and hexagonal-lattices produced via three-beam interference. Results demonstrate that constraints on individual-beam polarizations significantly impact patterning possibilities and must be included in the systematic design of an MBI system.

  17. Adaptive transmit selection with interference suppression

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2010-01-01

    This paper studies the performance of adaptive transmit channel selection in multipath fading channels. The adaptive selection algorithms are configured for single-antenna bandwidth-efficient or power-efficient transmission with as low transmit channel estimations as possible. Due to the fact that the number of active co-channel interfering signals and their corresponding powers experience random behavior, the adaptation to channels conditions, assuming uniform buffer and traffic loading, is proposed to be jointly based on the transmit channels instantaneous signal-to-noise ratios (SNRs) and signal-to- interference-plus- noise ratios (SINRs). Two interference cancelation algorithms, which are the dominant cancelation and the less complex arbitrary cancelation, are considered, for which the receive antenna array is assumed to have small angular spread. Analytical formulation for some performance measures in addition to several processing complexity and numerical comparisons between various adaptation schemes are presented. ©2010 IEEE.

  18. Unruh effect and macroscopic quantum interference

    CERN Document Server

    Steane, Andrew

    2015-01-01

    We investigate the influence of Unruh radiation on matter-wave interferometry experiments using neutral objects modeled as dielectric spheres. The Unruh effect leads to a loss of coherence through momentum diffusion. This is a fundamental source of decoherence that affects all objects having electromagnetic interactions. However, the effect is not large enough to prevent the observation of interference for objects of any size, even when the path separation is larger than the size of the object. When the acceleration in the interferometer arms is large, inertial tidal forces will disrupt the material integrity of the interfering objects before the Unruh decoherence of the centre of mass motion is sufficient to prevent observable interference.

  19. Multiscale Investigation of Chemical Interference in Proteins

    CERN Document Server

    Samiotakis, Antonios; Cheung, Margaret S

    2010-01-01

    We developed a multiscale approach (MultiSCAAL) that integrates the potential of mean force (PMF) obtained from all-atomistic molecular dynamics simulations with a knowledge-based energy function for coarse-grained molecular simulations in better exploring the energy landscape of a small protein under chemical interference such as chemical denaturation. An excessive amount of water molecules in all-atomistic molecular dynamics simulations often negatively impacts the sampling efficiency of some advanced sampling techniques such as the replica exchange method and it makes the investigation of chemical interferences on protein dynamics difficult. Thus, there is a need to develop an effective strategy that focuses on sampling structural changes in protein conformations rather than solvent molecule fluctuations. In this work, we address this issue by devising a multiscale simulation scheme (MultiSCAAL) that bridges the gap between all-atomistic molecular dynamics simulation and coarse-grained molecular simulation...

  20. Intercell Interference Coordination through Limited Feedback

    Directory of Open Access Journals (Sweden)

    Lingjia Liu

    2010-01-01

    Full Text Available We consider the applications of multicell transmission schemes to the downlink of future wireless communication networks. A multicell multiple-input multiple output-(MIMOs based scheme with limited coordination among neighboring base stations (BSs is proposed to effectively combat the intercell interference by taking advantage of the degreesoffreedom in the spatial domain. In this scheme, mobile users are required to feedback channel-related information to both serving base station and interfering base station. Furthermore, a chordal distance-based compression scheme is introduced to reduce the feedback overhead. The performance of the proposed scheme is investigated through theoretical analysis as well as system level simulations. Both results suggest that the so-called “intercell interference coordination through limited feedback” scheme is a very good candidate for improving the cell-edge user throughput as well as the average cell throughput of the future wireless communication networks.

  1. On interference types in electrolyte solutions

    International Nuclear Information System (INIS)

    A brief analysis of component interference types in electrolyte aqueous solutions is presented. On the example of studying ClO4- ion state in different (lithium, sodium, magnesium, cadmium, europium...) perchlorate solutions using molecular spectroscopy methods it is shown that ion-water interaction essentially depends on counterion nature. For deep understanding of interference processes in solutions with ion-molecular level usefulness of considering the system solubility isotherms is marked. On the example of solubility isotherms of several ternary systems (PrCl3-LiCl-H2O; Sc(ClO4)3-HClO4-H2O; PrCl3-RbCl-H2O; CdCl2-KCl-H2O) it is shown that different chemical nature of components results in various dominating interactions (mutual dehydration of electrolytes, dehydration of one of the components etc.). 6 refs.; 4 figs

  2. Electron Interference in Ballistic Graphene Nanoconstrictions

    Science.gov (United States)

    Baringhaus, Jens; Settnes, Mikkel; Aprojanz, Johannes; Power, Stephen R.; Jauho, Antti-Pekka; Tegenkamp, Christoph

    2016-05-01

    We realize nanometer size constrictions in ballistic graphene nanoribbons grown on sidewalls of SiC mesa structures. The high quality of our devices allows the observation of a number of electronic quantum interference phenomena. The transmissions of Fabry-Perot-like resonances are probed by in situ transport measurements at various temperatures. The energies of the resonances are determined by the size of the constrictions, which can be controlled precisely using STM lithography. The temperature and size dependence of the measured conductances are in quantitative agreement with tight-binding calculations. The fact that these interference effects are visible even at room temperature makes the reported devices attractive as building blocks for future carbon based electronics.

  3. Quantum interference between resonant and nonresonant photorecombination

    Science.gov (United States)

    Tu, B.; Xiao, J.; Yao, K.; Shen, Y.; Yang, Y.; Lu, D.; Li, W. X.; Qiu, M. L.; Wang, X.; Chen, C. Y.; Fu, Y.; Wei, B.; Zheng, C.; Huang, L. Y.; Zhang, B. H.; Tang, Y. J.; Hutton, R.; Zou, Y.

    2016-03-01

    In this paper, we present experimental and theoretical studies on the interference between resonant and nonresonant photorecombinations for the main resonances of ground-state He-, Be-, B-, C-, N-, and O-like W ions. Experiments were done using a fast electron energy scanning technique at the upgraded Shanghai electron-beam ion trap. Asymmetric resonances were observed, and their Fano factors, which measure the interference degree, were determined. The calculations were done under the framework of Fano's theory by using the flexible atomic code, in which the relativistic configuration interaction method was employed. Among the nine resonances studied in this work, eight experimental results agree with the calculation within experimental uncertainties. But the experimental result for the resonance of Be-like W ions, through the intermediate state of [(1s2s22p 1 /2) 12 p3 /2] 5 /2, deviates from its corresponding theoretical result by 1.3 times experimental uncertainty.

  4. Interference Rejection Techniques in DSSS Communication System

    Institute of Scientific and Technical Information of China (English)

    GONGXiangyang; HUGuangrui

    2003-01-01

    It is known that the narrowband interfer-ence rejection capability of a direct sequence (DS) spread spectrum (SS) system can be enhanced considerably by an interference rejection algorithm prior to correlating it with the pseudo noise (PN) sequence. For narrowband gaussian noise (NGN), the techniques in common use are transver-sal filter. It models SS signal and NGN as stationary, then utilizes temporal correlation difference between SS signal and NBL however, SS signal and NGN are cyclostation-ary (CS). CS signal has correlation in frequency domain called spectrum correlation, which can not be employed by transversal filter. In this article, SS signal and NBIare modeled as CS and FRESH filter is adopted to exploit the correlation both in time domain and frequency domain.Computer simulation shows that FRESH filter can improve the system performance considerably compared with con-ventional transversal filter.

  5. Interference Channels with Correlated Receiver Side Information

    OpenAIRE

    Liu, Nan; Gunduz, Deniz; Goldsmith, Andrea J.; Poor, H. Vincent

    2008-01-01

    The problem of joint source-channel coding in transmitting independent sources over interference channels with correlated receiver side information is studied. When each receiver has side information correlated with its own desired source, it is shown that source-channel code separation is optimal. When each receiver has side information correlated with the interfering source, sufficient conditions for reliable transmission are provided based on a joint source-channel coding scheme using the ...

  6. Tobacco Industry Interference with Tobacco Control

    OpenAIRE

    World Health Organization,

    2009-01-01

    A large body of evidence demonstrates that tobacco companies use a wide range of tactics to interfere with tobacco control. Such strategies include direct and indirect political lobbying and campaign contributions, financing of research, attempting to affect the course of regulatory and policy machinery and engaging in social responsibility initiatives as part of public relations campaigns. Although more and more is known about tobacco industry tactics, a systematic, comprehensive gu...

  7. Radio Frequency Interference Mitigation at the WSRT

    OpenAIRE

    Fridman, P. A.; Baan, W. A.; Millenaar, R. P.

    2010-01-01

    The sensitivity of radio astronomical stations is often limited by man-made radio frequency interference (RFI) due to a variety of terrestrial activities. An RFI mitigation subsystem (RFIMS) based on real-time digital signalprocessing is proposed here for the Westerbork Synthesis Radio Telescope based on a powerful field programmable gate array processor. In this system the radio astronomy signals polluted by RFI are "cleaned" with the RFIMS before routine back-end correlation processing take...

  8. Interference to satellite systems produced by rainscatter

    Science.gov (United States)

    Howell, R. G.; Thompson, P. T.

    1991-10-01

    Data, obtained from eight small dish receivers, placed around the United Kingdom, and designed to detect the scattering by rain of signals from the British Telecom (BT) 11 GHz microwave network, is presented. Fifteen site years of measurements were analyzed to produce cumulative distributions of effective receive antenna noise temperature and, where rainscattered signals were detected, cumulative distributions of transmission loss. The results obtained are compared with those predicted by a BT/University of Essex rainscatter interference prediction model (SCIMP).

  9. Colloquium: Quantum interference of clusters and molecules

    OpenAIRE

    Hornberger, Klaus; Gerlich, Stefan; Haslinger, Philipp; Nimmrichter, Stefan; Arndt, Markus

    2011-01-01

    We review recent progress and future prospects of matter wave interferometry with complex organic molecules and inorganic clusters. Three variants of a near-field interference effect, based on diffraction by material nanostructures, at optical phase gratings, and at ionizing laser fields are considered. We discuss the theoretical concepts underlying these experiments and the experimental challenges. This includes optimizing interferometer designs as well as understanding the role of decoheren...

  10. Research Progress on Multimode Interference Switches

    Institute of Scientific and Technical Information of China (English)

    GAO Qing; SHENG Zhi-rui; JIANG Xiao-qing; WANG Ming-hua

    2005-01-01

    Optical switches are key components for constructing optical communication networks, so it is necessary to design optical switches and optical switch arrays with high performance and low cost. As one type of optical switches, the multimode interference(MMI) switches have received considerable attention due to their unique merits. The structures and operation principles of various types of MMI switches are introduced,and the recent progresses of MMI switches are also discussed.

  11. Engine Power Effects on Support Interference

    OpenAIRE

    Horsten, B.J.C.; Veldhuis, L.L.M.

    2009-01-01

    Renewed interest in propeller propulsion on aircraft configurations combined with higher propeller loads lead to the question how the effects of the propulsion on model support disturbances should be accounted for. In this paper, the determination of engine power effects on support interference of sting-mounted models is demonstrated by a measurement on a four-engine turboprop aircraft. CFD results on a more generic model are presented in order to clarify the possible mechanism behind engine ...

  12. In Vivo Imaging of RNA Interference

    OpenAIRE

    Hong, Hao; Zhang, Yin; Cai, Weibo

    2010-01-01

    RNA interference (RNAi), an effective technique for regulating/silencing specific genes, can be applied to treat various diseases. Multiple clinical trials using RNAi are ongoing and molecular imaging can serve as a powerful tool in RNAi-based therapies. This brief review will highlight the current progress on in vivo imaging of RNAi delivery and silencing effects. Incorporation of suitable molecular imaging techniques into future RNAi-based clinical trials will provide more pieces of the puz...

  13. Development of Studies on RNA Interference

    Institute of Scientific and Technical Information of China (English)

    Li ZHANG; Yaqiong ZHANG; Lina SHE; Wenting XU; Yangying JIA; Shiqing XIE; WenliSUN; Quan LIANG

    2012-01-01

    RNA interference (RNAi), caused by endogenous or exogenous double- stranded RNA (dsRNA) homologous with target genes, refers to gene silencing widely existing in animals and plants. It was first found in plants, and now it has developed into a kind of biotechnology as well as an important approach in post- genome era. This paper is to summarize the achievements of studies on RNAi tech- nology in basic biology, medicine, pharmacy, botany and other fields.

  14. Process for preparing electromagnetic interference shileding materials

    OpenAIRE

    Thomassin, Jean-Michel; Jérôme, Christine; Detrembleur, Christophe; Alexandre, Michaël; Huynen, Isabelle

    2011-01-01

    The present invention relates to a process for preparing an electromagnetic interference shielding material, or a precursor thereof, comprising a first polymer matrix and carbon conductive loads, said process comprises the steps of: (a) Forming a reaction mixture comprising carbon conductive loads and a polymerizable medium said polymerizable medium comprising one or more monomers dissolved in a solvent, (b) Exposing the reaction mixture to polymerization conditions to polymerize said polymer...

  15. CRISPR Interference Directs Strand Specific Spacer Acquisition

    OpenAIRE

    Daan C Swarts; Cas Mosterd; van Passel, Mark W. J.; Brouns, Stan J. J.

    2012-01-01

    BACKGROUND: CRISPR/Cas is a widespread adaptive immune system in prokaryotes. This system integrates short stretches of DNA derived from invading nucleic acids into genomic CRISPR loci, which function as memory of previously encountered invaders. In Escherichia coli, transcripts of these loci are cleaved into small RNAs and utilized by the Cascade complex to bind invader DNA, which is then likely degraded by Cas3 during CRISPR interference. RESULTS: We describe how a CRISPR-activated E. coli ...

  16. Interferences in photolytic NO2 measurements: explanation for an apparent missing oxidant?

    Science.gov (United States)

    Reed, Chris; Evans, Mathew J.; Di Carlo, Piero; Lee, James D.; Carpenter, Lucy J.

    2016-04-01

    Measurement of NO2 at low concentrations (tens of ppts) is non-trivial. A variety of techniques exist, with the conversion of NO2 into NO followed by chemiluminescent detection of NO being prevalent. Historically this conversion has used a catalytic approach (molybdenum); however, this has been plagued with interferences. More recently, photolytic conversion based on UV-LED irradiation of a reaction cell has been used. Although this appears to be robust there have been a range of observations in low-NOx environments which have measured higher NO2 concentrations than might be expected from steady-state analysis of simultaneously measured NO, O3, jNO2, etc. A range of explanations exist in the literature, most of which focus on an unknown and unmeasured "compound X" that is able to convert NO to NO2 selectively. Here we explore in the laboratory the interference on the photolytic NO2 measurements from the thermal decomposition of peroxyacetyl nitrate (PAN) within the photolysis cell. We find that approximately 5 % of the PAN decomposes within the instrument, providing a potentially significant interference. We parameterize the decomposition in terms of the temperature of the light source, the ambient temperature, and a mixing timescale ( ˜ 0.4 s for our instrument) and expand the parametric analysis to other atmospheric compounds that decompose readily to NO2 (HO2NO2, N2O5, CH3O2NO2, IONO2, BrONO2, higher PANs). We apply these parameters to the output of a global atmospheric model (GEOS-Chem) to investigate the global impact of this interference on (1) the NO2 measurements and (2) the NO2 : NO ratio, i.e. the Leighton relationship. We find that there are significant interferences in cold regions with low NOx concentrations such as the Antarctic, the remote Southern Hemisphere, and the upper troposphere. Although this interference is likely instrument-specific, the thermal decomposition to NO2 within the instrument's photolysis cell could give an at least partial

  17. Segregation of unvoiced speech from nonspeech interference.

    Science.gov (United States)

    Hu, Guoning; Wang, DeLiang

    2008-08-01

    Monaural speech segregation has proven to be extremely challenging. While efforts in computational auditory scene analysis have led to considerable progress in voiced speech segregation, little attention has been given to unvoiced speech, which lacks harmonic structure and has weaker energy, hence more susceptible to interference. This study proposes a new approach to the problem of segregating unvoiced speech from nonspeech interference. The study first addresses the question of how much speech is unvoiced. The segregation process occurs in two stages: Segmentation and grouping. In segmentation, the proposed model decomposes an input mixture into contiguous time-frequency segments by a multiscale analysis of event onsets and offsets. Grouping of unvoiced segments is based on Bayesian classification of acoustic-phonetic features. The proposed model for unvoiced speech segregation joins an existing model for voiced speech segregation to produce an overall system that can deal with both voiced and unvoiced speech. Systematic evaluation shows that the proposed system extracts a majority of unvoiced speech without including much interference, and it performs substantially better than spectral subtraction. PMID:18681616

  18. Immunizing digital systems against electromagnetic interference

    Science.gov (United States)

    Ewing, P. D.; Korsah, K.; Antonescu, C.

    This paper discusses the development of the technical basis for acceptance criteria applicable to the immunization of digital systems against electromagnetic interference (EMI). The work is sponsored by the US Nuclear Regulatory Commission and stems from the safety-related issues that need to be addressed as a result of the application of digital instrumentation and control systems in nuclear power plants. Designers of digital circuits are incorporating increasingly higher clock frequencies and lower logic level voltages, thereby leading to potentially greater susceptibility of spurious interference being misinterpreted as legitimate logic. Development of the technical basis for acceptance criteria to apply to these digital systems centers around establishing good engineering practices to ensure that sufficient levels of electromagnetic compatibility (EMC) are maintained between the nuclear power plant's electronic and electromechanical systems. First, good EMC design and installation practices are needed to control the emissions from interference sources and thereby their impact on other nearby circuits and systems. Secondly, a test and evaluation program is needed to outline the EMI tests to be performed, the associated test methods to be followed, and adequate test limits to ensure that the circuit or system under test meets the recommended guidelines. Test and evaluation should be followed by periodic maintenance to assess whether the recommended EMI control practices continue to be adhered to as part of the routine operation of the nuclear power plant. By following these steps, the probability of encountering safety-related instrumentation problems associated with EMI will be greatly reduced.

  19. Visual working memory capacity and proactive interference.

    Directory of Open Access Journals (Sweden)

    Joshua K Hartshorne

    Full Text Available BACKGROUND: Visual working memory capacity is extremely limited and appears to be relatively immune to practice effects or the use of explicit strategies. The recent discovery that visual working memory tasks, like verbal working memory tasks, are subject to proactive interference, coupled with the fact that typical visual working memory tasks are particularly conducive to proactive interference, suggests that visual working memory capacity may be systematically under-estimated. METHODOLOGY/PRINCIPAL FINDINGS: Working memory capacity was probed behaviorally in adult humans both in laboratory settings and via the Internet. Several experiments show that although the effect of proactive interference on visual working memory is significant and can last over several trials, it only changes the capacity estimate by about 15%. CONCLUSIONS/SIGNIFICANCE: This study further confirms the sharp limitations on visual working memory capacity, both in absolute terms and relative to verbal working memory. It is suggested that future research take these limitations into account in understanding differences across a variety of tasks between human adults, prelinguistic infants and nonlinguistic animals.

  20. Cell phones and electromagnetic interference revisited.

    Science.gov (United States)

    2006-12-01

    Some media reports have inaccurately and incompletely interpreted recent studies, creating the impression that newer cell phone technology doesn't create enough electromagnetic interference (EMI) to affect medical equipment. As a result, hospitals are questioning whether existing restrictions on cell phone use can be eliminated. This article takes a closer look at the available evidence and explains that the evidence does, in fact, demonstrate an ongoing risk that EMI will affect medical devices. In addition, the article provides guidance on the impact that some newer communications technologies--namely, in-building cordless telephones, microcell systems, and Voice over Internet Protocol (VoIP) phones--may have on cell phone use and policies. Note that while this article focuses on cell phones--since they are the most common concern among hospitals--other types of wireless devices can also interfere with medical equipment. These include handheld messaging devices (e.g., BlackBerry products); multicommunication devices that combine the use of Wi-Fi, Bluetooth, and cellular communications; and cellular-capable computers. Healthcare facilities should apply the same policies to these devices as to cell phones. Two-way radios likewise present an interference risk, but require different policies, as we describe in a supplementary article within this Guidance Article. PMID:17300104

  1. Interference Phenomena in Medium Induced Radiation

    CERN Document Server

    Casalderrey-Solana, Jorge

    2011-01-01

    We consider the interference pattern for the medium-induced gluon radiation produced by a color singlet quark-antiquark antenna embedded in a QCD medium with size $L$ and `jet quenching' parameter $\\hat q$. Within the BDMPS-Z regime, we demonstrate that, for a dipole opening angle $\\theta_{q\\bar q} \\gg\\theta_c\\equiv {2}/{\\sqrt{\\hat q L^3}}$, the interference between the medium--induced gluon emissions by the quark and the antiquark is suppressed with respect to the direct emissions. This is so since direct emissions are delocalized throughout the medium and thus yield contributions proportional to $L$ while interference occurs only between emissions at early times, when both sources remain coherent. Thus, for $\\tqq \\gg\\theta_c$, the medium-induced radiation is the sum of the two spectra individually produced by the quark and the antiquark, without coherence effects like angular ordering. For $\\tqq \\ll\\theta_c$, the medium--induced radiation vanishes.

  2. 47 CFR 27.64 - Protection from interference.

    Science.gov (United States)

    2010-10-01

    ... MISCELLANEOUS WIRELESS COMMUNICATIONS SERVICES Technical Standards § 27.64 Protection from interference. Wireless Communications Service (WCS) stations operating in full accordance with applicable FCC rules and... provided against interference caused by tropospheric and ionospheric propagation of signals....

  3. Cryptic interference competition in swans foraging on cryptic prey

    NARCIS (Netherlands)

    Gyimesi, A.; Stillman, R.A.; Nolet, B.A.

    2010-01-01

    Interference can be defined as the reduction of intake rate caused by the presence of congeneric individuals. However, surrounding congeneric individuals may also accelerate food depletion. Therefore, it is difficult to quantify interference (contest) and exploitative (scramble) competition separate

  4. Interference with follicle stimulating hormone regulation of human ovarian function

    NARCIS (Netherlands)

    B.C.J.M. Fauser (Bart)

    1996-01-01

    textabstractThis review summarizes observations on the background and potential clinical significance of interference with follicle stimulating hormone (FSH) regulation of human ovarian function. This interference may occur at the level of the pituitary by the secretion

  5. An Experimental Investigation on the Interferences among Multiple Turbines in Onshore and Offshore Wind Farms

    Science.gov (United States)

    Tian, Wei; Ozbay, Ahmet; Hu, Hui

    2013-11-01

    We report an experimental study to investigate the wake interferences among multiple wind turbines on onshore and offshore wind farms. The experimental studies are conducted in a large-scale Aerodynamic/Atmospheric Boundary Layer (AABL) Wind Tunnel with an array of scaled three-blade Horizontal Axial Wind Turbine (HAWT) models placed in atmospheric boundary layer winds with different mean and turbulence characteristics to simulate the situations in onshore and offshore wind farms. In addition to measuring dynamic wind loads (both forces and moments) and the power outputs of the scaled turbine models, a Particle Image Velocity (PIV) system is used to conduct detailed flow field measurements to quantify the turbulent wake vortex flows and the wake interferences among the wind turbines sited over onshore and offshore wind farms with non-homogenous surface winds. The detailed flow field measurements are correlated with the dynamic wind loads and power output measurements to elucidate underlying physics in order to gain further insight into the characteristics of the dynamic wind loads and wake interferences among multiple wind turbines for higher total power yield and better durability of the wind turbines. The research work is funded by NSF and IAWIND.

  6. Transmission Interference Improvement of Railway Communication via Distributed Antennas System.

    OpenAIRE

    Lin, Siyu; Zhong , Zhangdui; Ai, Bo; Briso Rodriguez, Cesar

    2010-01-01

    Transmission interference is a key performance indicator of railway digital mobile communication system(RDMCS), whose performance will become worse in high-speed railway. The factors that influence the transmission interference of RDMCS are analyzed. Based on the relationship between speed and transmission interference, the scheme based on distributed antennas system (DAS) is proposed to improve transmission interference of RDMCS. The proposed scheme can reduce the collision probability betwe...

  7. Interference interactions in experimental pine-hardwood stands

    OpenAIRE

    Fredericksen, Todd Simon

    1991-01-01

    Competition for resources and other interference from non-crop vegetation often limits the productivity of pine and pine-hardwood forest stands in the southern United States. However, forest researchers have yet to fully quantify the effect of this interference on forest tree yield and there is an incomplete understanding of the biological mechanisms of interference. To better quantify the effects of interference interactions and elucidate their mechanisms, a field replacement series experime...

  8. Estimation Of Interference In Satellite/Ground Communications

    Science.gov (United States)

    Kantak, Anil V.

    1990-01-01

    Relative strengths of desired and interfering signals computed for known orbits. Satellite Interference Analysis and Simulation Using Personal Computers (AKSATINT) computer program calculates interference experienced by generic satellite communications receiving station from interfering satellite. Also computes interference-to-signal-power ratio, taking into account losses suffered by links. Of general use to designers of systems and managers of frequencies in selecting proper frequencies under interference scenarios. Written in BASIC.

  9. Quantum Interference of Multiple Beams Induced by Multiple Scattering

    DEFF Research Database (Denmark)

    Ott, Johan Raunkjær; Mortensen, N. Asger; Lodahl, Peter

    2011-01-01

    We report on quantum interference induced by the transmission of quantized light through a multiple-scattering medium. We show that entangled states can be created by multiple-scattering and that quantum interference survives disorder averaging.......We report on quantum interference induced by the transmission of quantized light through a multiple-scattering medium. We show that entangled states can be created by multiple-scattering and that quantum interference survives disorder averaging....

  10. Capacity Regions and Sum-Rate Capacities of Vector Gaussian Interference Channels

    CERN Document Server

    Shang, Xiaohu; Kramer, Gerhard; Poor, H Vincent

    2009-01-01

    The capacity regions of vector, or multiple-input multiple-output, Gaussian interference channels are established for very strong interference and aligned strong interference. Furthermore, the sum-rate capacities are established for Z interference, noisy interference, and mixed (aligned weak/intermediate and aligned strong) interference. These results generalize known results for scalar Gaussian interference channels.

  11. Non-Interference and Erasure Policies for Java Card Bytecode

    DEFF Research Database (Denmark)

    Hansen, René Rydhof; Probst, Christian W.

    2006-01-01

    Non-interference is the property of a program not to leak any secret information. In this paper we propose a notion of non-interference for an abstract version of the Java Card bytecode language. Furthermore an information-flow analysis for verifying non-interference is developed and proved sound...

  12. Interference of an array of independent Bose-Einstein condensates

    CERN Document Server

    Hadzibabic, Z; Bretin, V; Stock, S; Battelier, Baptiste; Bretin, Vincent; Hadzibabic, Zoran; Proxy, Jean Dalibard; Stock, Sabine; ccsd-00001592, ccsd

    2004-01-01

    We have observed high-contrast matter wave interference between 30 Bose-Einstein condensates with uncorrelated phases. Interference patterns were observed after independent condensates were released from a one-dimensional optical lattice and allowed to expand and overlap. This initially surprising phenomenon is explained with a simple theoretical model which generalizes the analysis of the interference of two independent condensates.

  13. 37 CFR 2.93 - Institution of interference.

    Science.gov (United States)

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Institution of interference. 2.93 Section 2.93 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE....93 Institution of interference. An interference is instituted by the issuance of a notice...

  14. 47 CFR 74.643 - Interference to geostationary-satellites.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Interference to geostationary-satellites. 74... Television Broadcast Auxiliary Stations § 74.643 Interference to geostationary-satellites. Applicants and licensees must comply with § 101.145 of this chapter to minimize the potential of interference...

  15. 47 CFR 101.145 - Interference to geostationary-satellites.

    Science.gov (United States)

    2010-10-01

    ... interference to an authorized satellite system, said transmission path may be authorized on waiver basis where... 47 Telecommunication 5 2010-10-01 2010-10-01 false Interference to geostationary-satellites. 101... RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.145 Interference to...

  16. 47 CFR 101.105 - Interference protection criteria.

    Science.gov (United States)

    2010-10-01

    ... SERVICES FIXED MICROWAVE SERVICES Technical Standards § 101.105 Interference protection criteria. (a) The... carrier-beat interference must not exceed 50 pwpO. (2) To short-haul analog systems employing frequency... not exceed 250 pwpO per exposure; or (ii) Due to co-channel carrier-beat interference must not...

  17. Addressing Cultural and Native Language Interference in Second Language Acquisition

    Science.gov (United States)

    Allard, Daniele; Bourdeau, Jacqueline; Mizoguchi, Riichiro

    2011-01-01

    This paper addresses the problem of cultural and native language interference in second/foreign language acquisition. More specifically, it examines issues of interference that can be traced to a student's native language and that also have a cultural component. To this effect, an understanding of what actually comprises both interference and…

  18. GNSS interference and anti interference technology%GNSS干扰及抗干扰技术

    Institute of Scientific and Technical Information of China (English)

    任韦

    2016-01-01

    The global navigation satellite system(GNSS)provides low energy level radio frequency(RF) navigation signal,which is easy to be affected by the interference of RF,which leads to the decrease of the navigation precision or the complete loss of the receiver This paper introduces the types,technical means and implementation methods of GNSS interference.The advantages and disadvantages and the application range of anti interference technology used in different jamming are analyzed. An anti interference scheme is designed by using various anti interference techniques.%全球导航卫星系统(GNSS)提供的低能级射频(RF)导航信号,易受到RF干扰的影响而导致导航精度的降低或者接收机的完全失锁.本文介绍了GNSS干扰的类型、技术手段和实施方式.针对不同干扰所采用的抗干扰技术,分析了其优缺点和适用范围.利用多种抗干扰技术初步设计了一个抗干扰方案.

  19. Angular Momentum Sensitive Two-Center Interference

    Science.gov (United States)

    Ilchen, M.; Glaser, L.; Scholz, F.; Walter, P.; Deinert, S.; Rothkirch, A.; Seltmann, J.; Viefhaus, J.; Decleva, P.; Langer, B.; Knie, A.; Ehresmann, A.; Al-Dossary, O. M.; Braune, M.; Hartmann, G.; Meissner, A.; Tribedi, L. C.; AlKhaldi, M.; Becker, U.

    2014-01-01

    In quantum mechanics the Young-type double-slit experiment can be performed with electrons either traveling through a double slit or being coherently emitted from two inversion symmetric molecular sites. In the latter one the valence photoionization cross sections of homonuclear diatomic molecules were predicted to oscillate over kinetic energy almost 50 years ago. Beyond the direct proof of the oscillatory behavior of these photoionization cross sections σ, we show that the angular distribution of the emitted electrons reveals hitherto unexplored information on the relative phase shift between the corresponding partial waves through two-center interference patterns.

  20. Interference subspace rejection in wideband CDMA:

    DEFF Research Database (Denmark)

    Hansen, Henrik; Affes, Sofiene; Mermelstein, Paul

    2001-01-01

    This paper extends our study on a multi-user receiver structure for base-station receivers with antenna arrays in multicellular systems. The receiver employs a beamforming structure with constraints that nulls the signal component in appropriate interference subspaces. Here we introduce a new mode...... result of subspace suppression, as well as allow asynchronous transmission. Performance differences arise between the modes due to different sensitivities to channel identification and data detection errors. For homogeneous high data-rate situations ISR-DX manifests the best performance. However, due to...... its reduced complexity, ISR-TRX appears to offer the best complexity-performance tradeoffs....

  1. Electromagnetic interference considerations for cockpit AMLCD displays

    Science.gov (United States)

    Case, Gary D.; Prache, Olivier

    1994-06-01

    OIS has developed various active matrix liquid crystal displays for the cockpits of several aircraft. Some of these displays have been tested for and are being designed for compliance with the military electromagnetic interference (EMI) requirements spelled out in MIL-STD- 461. Detailed analysis has also been performed on the addressed cell assembly and the flex circuitry to provide guidelines for EMI design. This paper presents the results of tests performed, steps which were taken to become EMI compliant and the results of the analysis.

  2. Removal of interference from external coherent signals

    CERN Document Server

    Sintes, A M

    2000-01-01

    We present a technique that we call coherent line removal, for removing external coherent interference from gravitational wave interferometer data. We illustrate the usefulness of this technique applying it to the the data produced by the Glasgow laser interferometer in 1996 and removing all those lines corresponding to the electricity supply frequency and its harmonics. We also find that this method seems to reduce the level of non-Gaussian noise present in the interferometer and therefore, it can raise the sensitivity and duty cycle of the detectors.

  3. Interference Tests at Kawerau, New Zealand

    Energy Technology Data Exchange (ETDEWEB)

    Burnell, John G.; McGuinness, Mark J.

    1987-01-20

    Analysis of interference tests at the Kawerau geothermal field in New Zealand has indicated that the reservoir may be viewed on a coarse scale as a two-layer structure. While these layers have high permeabilities, they are in poor hydrological communication with each other. The shallower layer is modelled as a finite cylindrical reservoir. The deeper layer is modelled as a larger cylindrical reservoir with recharge from the sides. The fitted permeabilities and storativities suggest the importance of flow in fractures at Kawerau. 2 tabs., 14 figs., 8 refs.

  4. Stroop interference in adults with dyslexia.

    Science.gov (United States)

    Proulx, Michael J; Elmasry, Hannah-May

    2015-01-01

    Prior research on developmental dyslexia using Stroop tasks with young participants has found increased interference in participants with dyslexia relative to controls. Here we extend these findings to adult participants, and introduce a novel test of Stroop incongruity, whereby the color names appeared on an object colored in the incongruent color. The results imply that impaired inhibitory and executive attentional mechanisms are still deficient in adults with dyslexia and that other forms of attentional mechanisms, such as object-based attention, might also be impaired in dyslexia. Dyslexia arises not only from deficits in phonological processing, but from attentional mechanisms as well.

  5. Radio Frequency Interference Mitigation at the WSRT

    CERN Document Server

    Fridman, P A; Millenaar, R P

    2010-01-01

    The sensitivity of radio astronomical stations is often limited by man-made radio frequency interference (RFI) due to a variety of terrestrial activities. An RFI mitigation subsystem (RFIMS) based on real-time digital signalprocessing is proposed here for the Westerbork Synthesis Radio Telescope based on a powerful field programmable gate array processor. In this system the radio astronomy signals polluted by RFI are "cleaned" with the RFIMS before routine back-end correlation processing takes place. The high temporal and frequency resolution of RFIMS allows the detection and excision of RFI better than do standard radio telescope back-end configurations.

  6. Quantum radiation reaction: from interference to incoherence

    CERN Document Server

    Dinu, Victor; Ilderton, Anton; Marklund, Mattias; Torgrimsson, Greger

    2015-01-01

    We investigate quantum radiation reaction in laser-electron interactions across different energy and intensity regimes. Using a fully quantum approach which also accounts exactly for the effect of the strong laser pulse on the electron motion, we identify in particular a regime in which radiation reaction is dominated by quantum interference. We find signatures of quantum radiation reaction in the electron spectra which have no classical analogue and which cannot be captured by the incoherent approximations typically used in the high-intensity regime. These signatures are measurable with presently available laser and accelerator technology.

  7. The Acceptability of Speech with Radio Interference

    DEFF Research Database (Denmark)

    Baykaner, K.; Hummersone, H.; Mason, R.;

    2014-01-01

    A listening test was conducted to investigate the acceptability of audio-on-audio interference for radio programs featuring speech as the target. Twenty-one subjects, including naïve and expert listeners, were presented with 200 randomly assigned pairs of stimuli and asked to report, for each trial......, whether the listening scenario was acceptable or unacceptable. Stimuli pairs were set to randomly selected SNRs ranging from 0 to 45 dB. Results showed no significant difference between subjects according to listening experience. A logistic regression to acceptability was carried out based on SNR. The...

  8. Transient interference of transmission and incidence

    CERN Document Server

    Pérez-Prieto, A L; Muga, J G

    2000-01-01

    Due to a transient quantum interference during a wavepacket collision with a potential barrier, a particular momentum, that depends on the potential parameters but is close to the initial average momentum, becomes suppressed. The hole left pushes the momentum distribution outwards leading to a significant constructive enhancement of lower and higher momenta. This is explained in the momentum complex-plane language in terms of a saddle point and two contiguous ``structural'' poles, which are not associated with resonances but with incident and transmitted components of the wavefunction.

  9. Multipolar interference for directed light emission.

    Science.gov (United States)

    Hancu, Ion M; Curto, Alberto G; Castro-López, Marta; Kuttge, Martin; van Hulst, Niek F

    2014-01-01

    By directing light, optical antennas can enhance light-matter interaction and improve the efficiency of nanophotonic devices. Here we exploit the interference among the electric dipole, quadrupole, and magnetic dipole moments of a split-ring resonator to experimentally realize a compact directional optical antenna. This single-element antenna design robustly directs emission even when covered with nanometric emitters at random positions, outperforming previously demonstrated nanoantennas with a bandwidth of 200 nm and a directivity of 10.1 dB from a subwavelength structure. The advantages of this approach bring directional optical antennas closer to practical applications.

  10. Electromagnetic Interference in Implantable Rhythm Devices: Comment

    OpenAIRE

    Ramachandran, PV

    2002-01-01

    This is a short comment on the editorial on Electromagnetic Interference in Implantable Rhythm Devices - The Indian Scenario in the July-September issue of the journal.1 Regarding the statement: "Systems working at 0.5 Tesla are available in the country so that it may be considered in such situations..." , though the author conveys his point, it gives reader a feeling that 0.5 Tesla magnetic resonance imaging (MRI) units are advantageous. In fact for every other diagnostic purpose we would li...

  11. Exponentially tapered multi-mode interference couplers

    Institute of Scientific and Technical Information of China (English)

    Jijiang Wu; Bangren Shi; Mei Kong

    2006-01-01

    @@ Optical couplers are important components in photonic integrated circuits. The multi-mode interference (MMI) coupler is a good candidate because of its bandwidth, polarization properties, and manufacturing tolerances. A MMI coupler with the exponentially tapered multi-mode waveguide is proposed in order to reduce the scale of the MMI device. Compared with parabolically tapered structure which has been successfully used in the MMI devices, this structure can further reduce the length of devices. Simulation results by the beam propagation method for MMI couplers are given. The effectiveness of this structure for reducing MMI device length is proved.

  12. Interferences in reactor neutron activation analyses

    International Nuclear Information System (INIS)

    It has been shown that interfering reactions may occur in neutron activation analyses of aluminum and zinc matrixes, commonly used in nuclear areas. The interferences analysed were: Al2713 (n, α) Na2411 and Zn6430 (n, p) Cu6429. The method used was the non-destructive neutron activation analysis and the spectra were obtained in a 1024 multichannel system coupled with a Ge(Li) detector. Sodium was detected in aluminum samples from the reactor tank and pneumatic transfer system. The independence of the sodium concentration in samples in the range of 0 - 100 ppm is shown by the attenuation obtained with the samples encapsulated in cadmium. (Author)

  13. Strong Correlation of Fluorescence Photons without Quantum Interference

    Institute of Scientific and Technical Information of China (English)

    HU Xiang-Ming; WANG Fei

    2007-01-01

    It has been predicted that a driven three-level V atom can emit strongly correlated fluorescence photons in the presence of quantum interference. Here we examine the effects of quantum interference on the intensity correlation of fluorescence photons emitted from a driven three-level A atom. Unexpectedly, strong correlation occurs without quantum interference. The quantum interference tends to reduce the correlation function to a normal level. The essential difference between these two cases is traced to the different effects of quantum interference on coherent population trapping (CPT). For the V atom, quantum interference and coherent excitation combine to lead to CPT. For the A atom, however, the quantum interference tends to spoil CPT while the coherent excitation induces the effect.

  14. Reliability Estimations of Control Systems Effected by Several Interference Sources

    Institute of Scientific and Technical Information of China (English)

    Deng Bei-xing; Jiang Ming-hu; Li Xing

    2003-01-01

    In order to estab lish the sufficient and necessary condition that arbitrarily reliable systems can not be construc-ted with function elements under interference sources, it is very important to expand set of interference sources with the above property. In this paper, the models of two types of in-terference sources are raised respectively: interference source possessing real input vectors and constant reliable interference source. We study the reliability of the systems effected by the interference sources, and the lower bound of the reliability is presented. The results show that it is impossible that arbi-trarily reliable systems can not be constructed with the ele-ments effected by above interference sources.

  15. Aligned Interference Neutralization and the Degrees of Freedom of the 2x2x2 Interference Channel

    CERN Document Server

    Gou, Tiangao; Jeon, Sang-Woon; Chung, Sae-Young

    2010-01-01

    We show that the 2x2x2 interference channel, i.e., the multihop interference channel formed by concatenation of two 2-user interference channels achieves the min-cut outer bound value of 2 DoF, for almost all values of channel coefficients, for both time-varying or fixed channel coefficients. The key to this result is a new idea, called aligned interference neutralization, that provides a way to align interference terms over each hop in a manner that allows them to be cancelled over the air at the last hop.

  16. Stationary Wave Interference and its Relation to Tropical Convection and Climate Extremes

    Science.gov (United States)

    Feldstein, S. B.; Goss, M.; Lee, S.

    2015-12-01

    The impact of interference between transient eddies and the climatological stationary eddies is examined with ERA-Interim Reanalysis data. Composite calculations show that constructive interference during winter occurs about one week after enhanced Warm Pool convection, and is followed by the excitation of the positive phase of the Pacific/North American teleconnection pattern, an increase in surface air temperature over much of the extratropical Northern Hemisphere, along with a reduction of sea ice in the Barents and Kara Seas, a deceleration of the stratospheric polar vortex, and the excitation of the negative phase of the Arctic Oscillation. This surface warming does occur without prior Warm Pool convection, but it is enhanced and prolonged when constructive interference occurs in concert with the convection. This suggests that climate extremes may be more likely to occur when particular processes, such as Warm Pool convection and constructive interference, occur together. Opposite features are observed when there is destructive interference. To further investigate the influence of tropical convection, a series of idealized multi-level primitive equation model calculations is performed. The model's heating profiles are determined from composite CMAP precipitation anomalies for La Niña and El Niño months, and for MJO phase 1 and phase 5. As in the atmosphere, the model calculations find extratropical 300-hPa geopotential height anomalies of opposite sign for MJO phase 1 and El Nino heating, even though the heating profiles closely resemble each other. (Analogous results were found for MJO phase 5 and La Nina.) The model was also run with individual heating anomalies in key geographic locations. The results suggest that the extratropical response to both ENSO and MJO convective heating anomalies can be understood as arising from the competing influences of Warm Pool and central Pacific tropical convection. These results allude to the possibility that the

  17. Fabrication of Nanoimprint Stamp Using Interference Lithography

    Institute of Scientific and Technical Information of China (English)

    CHEN Xian-Zhong; LI Hai-Ying

    2007-01-01

    Interference lithography is used to fabricate a nanoimprint stamp, which is a key step for nanoimprint lithography.A layer of chromium in thickness of about 20 nm is deposited on the newly cleaned fused silica substrate by thermal evaporation, and a layer of positive resist in thickness of 150nm is spun on the chromium layer. Some patterns,including lines, holes and pillars, are observed on the photoresist film by exposing the resist to interference patterns and they are then transferred to the chromium layer by wet etching. Fused silica stamps are fabricated by reactive ion etching with CHF3/O2 as etchants using the chromium layer as etch mask. An atomic force microscope is used to analyse the pattern transfer in each step. The results show that regular hole patterns of fused silica, with average full width 143 nm at half maximum (FWHM), average hole depth of 76nm and spacing of 450nm, have been fabricated. The exposure method is fast, inexpensive and applicable for fabrication of nanoimprint stamps with large areas.

  18. Discrete interference modeling via boolean algebra.

    Science.gov (United States)

    Beckhoff, Gerhard

    2011-01-01

    Two types of boolean functions are considered, the locus function of n variables, and the interval function of ν = n - 1 variables. A 1-1 mapping is given that takes elements (cells) of the interval function to antidual pairs of elements in the locus function, and vice versa. A set of ν binary codewords representing the intervals are defined and used to generate the codewords of all genomic regions. Next a diallelic three-point system is reviewed in the light of boolean functions, which leads to redefining complete interference by a logic function. Together with the upper bound of noninterference already defined by a boolean function, it confines the region of interference. Extensions of these two functions to any finite number of ν are straightforward, but have been also made in terms of variables taken from the inclusion-exclusion principle (expressing "at least" and "exactly equal to" a decimal integer). Two coefficients of coincidence for systems with more than three loci are defined and discussed, one using the average of several individual coefficients and the other taking as coefficient a real number between zero and one. Finally, by way of a malfunction of the mod-2 addition, it is shown that a four-point system may produce two different functions, one of which exhibiting loss of a class of odd recombinants.

  19. Normalized GNSS interference pattern technique for altimetry.

    Science.gov (United States)

    Ribot, Miguel Angel; Kucwaj, Jean-Christophe; Botteron, Cyril; Reboul, Serge; Stienne, Georges; Leclère, Jérôme; Choquel, Jean-Bernard; Farine, Pierre-André; Benjelloun, Mohammed

    2014-01-01

    It is well known that reflected signals from Global Navigation Satellite Systems (GNSS) can be used for altimetry applications, such as monitoring of water levels and determining snow height. Due to the interference of these reflected signals and the motion of satellites in space, the signal-to-noise ratio (SNR) measured at the receiver slowly oscillates. The oscillation rate is proportional to the change in the propagation path difference between the direct and reflected signals, which depends on the satellite elevation angle. Assuming a known receiver position, it is possible to compute the distance between the antenna and the surface of reflection from the measured oscillation rate. This technique is usually known as the interference pattern technique (IPT). In this paper, we propose to normalize the measurements in order to derive an alternative model of the SNR variations. From this model, we define a maximum likelihood estimate of the antenna height that reduces the estimation time to a fraction of one period of the SNR variation. We also derive the Cramér-Rao lower bound for the IPT and use it to assess the sensitivity of different parameters to the estimation of the antenna height. Finally, we propose an experimental framework, and we use it to assess our approach with real GPS L1 C/A signals. PMID:24922453

  20. Quantum interference in an interfacial superconductor

    Science.gov (United States)

    Goswami, Srijit; Mulazimoglu, Emre; Monteiro, Ana M. R. V. L.; Wölbing, Roman; Koelle, Dieter; Kleiner, Reinhold; Blanter, Ya. M.; Vandersypen, Lieven M. K.; Caviglia, Andrea D.

    2016-10-01

    The two-dimensional superconductor that forms at the interface between the complex oxides lanthanum aluminate (LAO) and strontium titanate (STO) has several intriguing properties that set it apart from conventional superconductors. Most notably, an electric field can be used to tune its critical temperature (Tc; ref. 7), revealing a dome-shaped phase diagram reminiscent of high-Tc superconductors. So far, experiments with oxide interfaces have measured quantities that probe only the magnitude of the superconducting order parameter and are not sensitive to its phase. Here, we perform phase-sensitive measurements by realizing the first superconducting quantum interference devices (SQUIDs) at the LAO/STO interface. Furthermore, we develop a new paradigm for the creation of superconducting circuit elements, where local gates enable the in situ creation and control of Josephson junctions. These gate-defined SQUIDs are unique in that the entire device is made from a single superconductor with purely electrostatic interfaces between the superconducting reservoir and the weak link. We complement our experiments with numerical simulations and show that the low superfluid density of this interfacial superconductor results in a large, gate-controllable kinetic inductance of the SQUID. Our observation of robust quantum interference opens up a new pathway to understanding the nature of superconductivity at oxide interfaces.

  1. Relay self interference minimisation using tapped filter

    KAUST Repository

    Jazzar, Saleh

    2013-05-01

    In this paper we introduce a self interference (SI) estimation and minimisation technique for amplify and forward relays. Relays are used to help forward signals between a transmitter and a receiver. This helps increase the signal coverage and reduce the required transmitted signal power. One problem that faces relays communications is the leaked signal from the relay\\'s output to its input. This will cause an SI problem where the new received signal at the relay\\'s input will be added with the unwanted leaked signal from the relay\\'s output. A Solution is proposed in this paper to estimate and minimise this SI which is based upon using a tapped filter at the destination. To get the optimum weights for this tapped filter, some channel parameters must be estimated first. This is performed blindly at the destination without the need of any training. This channel parameter estimation method is named the blind-self-interference-channel-estimation (BSICE) method. The next step in the proposed solution is to estimate the tapped filter\\'s weights. This is performed by minimising the mean squared error (MSE) at the destination. This proposed method is named the MSE-Optimum Weight (MSE-OW) method. Simulation results are provided in this paper to verify the performance of BSICE and MSE-OW methods. © 2013 IEEE.

  2. Normalized GNSS interference pattern technique for altimetry.

    Science.gov (United States)

    Ribot, Miguel Angel; Kucwaj, Jean-Christophe; Botteron, Cyril; Reboul, Serge; Stienne, Georges; Leclère, Jérôme; Choquel, Jean-Bernard; Farine, Pierre-André; Benjelloun, Mohammed

    2014-06-11

    It is well known that reflected signals from Global Navigation Satellite Systems (GNSS) can be used for altimetry applications, such as monitoring of water levels and determining snow height. Due to the interference of these reflected signals and the motion of satellites in space, the signal-to-noise ratio (SNR) measured at the receiver slowly oscillates. The oscillation rate is proportional to the change in the propagation path difference between the direct and reflected signals, which depends on the satellite elevation angle. Assuming a known receiver position, it is possible to compute the distance between the antenna and the surface of reflection from the measured oscillation rate. This technique is usually known as the interference pattern technique (IPT). In this paper, we propose to normalize the measurements in order to derive an alternative model of the SNR variations. From this model, we define a maximum likelihood estimate of the antenna height that reduces the estimation time to a fraction of one period of the SNR variation. We also derive the Cramér-Rao lower bound for the IPT and use it to assess the sensitivity of different parameters to the estimation of the antenna height. Finally, we propose an experimental framework, and we use it to assess our approach with real GPS L1 C/A signals.

  3. Normalized GNSS Interference Pattern Technique for Altimetry

    Directory of Open Access Journals (Sweden)

    Miguel Angel Ribot

    2014-06-01

    Full Text Available It is well known that reflected signals from Global Navigation Satellite Systems (GNSS can be used for altimetry applications, such as monitoring of water levels and determining snow height. Due to the interference of these reflected signals and the motion of satellites in space, the signal-to-noise ratio (SNR measured at the receiver slowly oscillates. The oscillation rate is proportional to the change in the propagation path difference between the direct and reflected signals, which depends on the satellite elevation angle. Assuming a known receiver position, it is possible to compute the distance between the antenna and the surface of reflection from the measured oscillation rate. This technique is usually known as the interference pattern technique (IPT. In this paper, we propose to normalize the measurements in order to derive an alternative model of the SNR variations. From this model, we define a maximum likelihood estimate of the antenna height that reduces the estimation time to a fraction of one period of the SNR variation. We also derive the Cramér–Rao lower bound for the IPT and use it to assess the sensitivity of different parameters to the estimation of the antenna height. Finally, we propose an experimental framework, and we use it to assess our approach with real GPS L1 C/A signals.

  4. New Interference Mechanism Controls Ultracold Chemistry

    Science.gov (United States)

    Kendrick, Brian K.; Hazra, Jisha; Balakrishnan, N.

    2016-05-01

    A newly discovered interference mechanism has been shown to control the outcome of ultracold chemical reactions. The mechanism originates from the unique properties associated with ultracold collisions, namely: (1) isotropic (s-wave) scattering and (2) an effective quantization of the scattering phase shift (which originates from the bound state structure of the molecule). These two properties can lead to maximum constructive or destructive interference between two interfering reaction pathways (such as exchange and non-exchange in systems with two or more identical nuclei). If the molecular system exhibits a conical intersection, then the associated geometric phase is shown to act as a ``quantum switch'' which can turn the reactivity on or off. Reaction rate coefficients for the O + OH --> H + O2 and H + H2, reactions are presented which explicitly demonstrate the effect. Experimentalists might exploit this new mechanism to control ultracold reactions by the application of external electric or magnetic fields or by the selection of a particular nuclear spin state. This work was supported in part by the LDRD program (Grant No. 20140309ER) at LANL (B.K.) and by NSF Grant PHY-1505557 (N.B.) and ARO MURI Grant No. W911NF-12-1-0476 (N.B.).

  5. Original Approaches for Solving Electromagnetic Interference Problems

    Directory of Open Access Journals (Sweden)

    CHRISTOFORIDIS, G. C.

    2009-06-01

    Full Text Available The accurate calculation of the current densities induced in layered soil by HV transmission lines in normal conditions is one of the most important steps in the study of the electromagnetic interference between transmission lines and underground metallic structures (i.e. metallic gas pipelines. In electromagnetic interference problems, the best way to investigate the soil's behavior as conducting media is to determine the current distribution within ground. The aim of the present paper is to examine the level of influence that soil layers with different resistivity have on the induced current densities. New analytical formulas for the induced current densities in the two-layer soil case are derived. The determined formulas contain semi-infinite integral terms which are calculated through a stable and efficient numerical integration scheme, in order to overcome the problems arising from the oscillate form of the infinite integrals. In the second part of the paper, the author's contribution relates to the exposure and implementation of a robust Monte Carlo simulation method, in an original approach, for solving ill-posed synthesis magnetic or electric field problems.

  6. RNA interference: Antiviral weapon and beyond

    Institute of Scientific and Technical Information of China (English)

    Quan-Chu Wang; Qing-He Nie; Zhi-Hua Feng

    2003-01-01

    RNA interference (RNAi) is a remarkable type of gene regulation based on sequence-specific targeting and degradation of RNA. The term encompasses related pathways found in a broad range of eukaryotic organisms, including fungi, plants, and animals. RNA interference is part of a sophisticated network of interconnected pathways for cellular defense, RNA surveillance, and development and it may become a powerful tool to manipulate gene expression experimentally. RNAi technology is currently being evaluated not only as an extremely powerful instrument for functional genomic analyses, but also as a potentially useful method to develop specific dsRNA based gene-silencing therapeutics.Several laboratories have been interested in using RNAi to control viral infection and many reports in Nature and in Cell show that short interfering (si) RNAs can inhibit infection by HIV-1, polio and hepatitis C viruses in a sequence-specific manner. RNA-based strategies for gene inhibition in mammalian cells have recently been described, which offer the promise of antiviral therapy.

  7. Interference Channels with Rate-Limited Feedback

    CERN Document Server

    Vahid, Alireza; Avestimehr, Amir Salman

    2011-01-01

    We study the effect of rate-limited feedback on the capacity region of the two-user interference channel. We consider three different interference models: El Gamal-Costa deterministic model, the linear deterministic model, and the Gaussian model. For the first two models, we develop an achievable scheme that combines three techniques: Han-Kobayashi message splitting, quantize-and-binning, and partial decode-and-forward. We also derive new outer-bounds to show the optimality of our scheme under the linear deterministic model. For the Gaussian model, we establish outer-bounds on the capacity region with rate-limited feedback. Employing lattice codes and the ideas developed in the first two models, we also propose a transmission strategy for the Gaussian model. For symmetric channel gains, we prove that the gap between the achievable sum-rate of the proposed scheme and the outer-bound is bounded by a constant number of bits, independent of the channel gains.

  8. Carbon Nanotube Superconducting Quantum Interference Device.

    Science.gov (United States)

    Bouchiat, Vincent; Cleuziou, Jean-Pierre; Ondarcuhu, Thierry; Monthioux, Marc; Wernsdorfer, Wolfgang

    2007-03-01

    We report on the study of a superconducting quantum interference device (SQUID) with Josephson junctions made of portions of metallic single-walled carbon nanotube [1]. Quantum confinement in each nanotube junction induces a discrete quantum dot (QD) energy level structure, which can be controlled with a lateral electrostatic gate. In addition, a backgate electrode can vary the transparency of the QD barriers, thus permitting to change the hybridization of the QD states with the superconducting contacts [2]. The gates are also used to directly tune the quantum phase interference of the Cooper pairs circulating in the SQUID ring. Optimal modulation of a 6nA supercurrent current with magnetic flux is achieved when both QD junctions are in the ``on'' or ``off'' state. Futhermore, the SQUID design establishes that these CNT Josephson junctions can be used as gate-controlled π-junctions. This allow to verify that the sign of the current-phase relation across a proximity coupled Qdot can be reversed with a gate voltage. Noise studies shows that the noise figure of the nanotube SQUID together with the size of the junction should allow the detection of a single molecule magnet. [1] J-P. Cleuziou et al. Nature Nanotec., 1, 53, (2006). [2] J-P. Cleuziou et al. cond-mat/0610622.

  9. Ultrawideband Electromagnetic Interference to Aircraft Radios

    Science.gov (United States)

    Ely, Jay J.; Fuller, Gerald L.; Shaver, Timothy W.

    2002-01-01

    A very recent FCC Final Rule now permits marketing and operation of new products that incorporate Ultrawideband (UWB) technology into handheld devices. Wireless product developers are working to rapidly bring this versatile, powerful and expectedly inexpensive technology into numerous consumer wireless devices. Past studies addressing the potential for passenger-carried portable electronic devices (PEDs) to interfere with aircraft electronic systems suggest that UWB transmitters may pose a significant threat to aircraft communication and navigation radio receivers. NASA, United Airlines and Eagles Wings Incorporated have performed preliminary testing that clearly shows the potential for handheld UWB transmitters to cause cockpit failure indications for the air traffic control radio beacon system (ATCRBS), blanking of aircraft on the traffic alert and collision avoidance system (TCAS) displays, and cause erratic motion and failure of instrument landing system (ILS) localizer and glideslope pointers on the pilot horizontal situation and attitude director displays. This paper provides details of the preliminary testing and recommends further assessment of aircraft systems for susceptibility to UWB electromagnetic interference.

  10. Atmospheric composition change: Ecosystems-Atmosphere interactions

    NARCIS (Netherlands)

    Fowler, D.; Pilegaard, K.; Sutton, M.A.; Ambus, P.; Raivonen, M.; Duyzer, J.; Simpson, D.; Fagerli, H.; Fuzzi, S.; Schjoerring, J.K.; Granier, C.; Neftel, A.; Isaksen, I.S.A.; Laj, P.; Maione, M.; Monks, P.S.; Burkhardt, J.; Daemmgen, U.; Neirynck, J.; Personne, E.; Wichink Kruit, R.J.; Butterbach-Bahl, K.; Flechard, C.; Tuovinen, J.P.; Coyle, M.; Gerosa, G.; Loubet, B.; Altimir, N.; Gruenhage, L.; Ammann, C.; Cieslik, S.; Paoletti, E.; Mikkelsen, T.N.; Ro-Poulsen, H.; Cellier, P.; Cape, J.N.; Horvath, L.; Loreto, F.; Niinemets, U.; Palmer, P.I.; Rinne, J.; Misztal, P.; Nemitz, E.; Nilsson, D.; Pryor, S.; Gallagher, M.W.; Vesala, T.; Skiba, U.; Brueggemann, N.; Zechmeister-Boltenstern, S.; Williams, J.; O'Dowd, C.; Facchini, M.C.; Leeuw, de G.; Flossman, A.; Chaumerliac, N.; Erisman, J.W.

    2009-01-01

    Ecosystems and the atmosphere: This review describes the state of understanding the processes involved in the exchange of trace gases and aerosols between the earth's surface and the atmosphere. The gases covered include NO, NO2, HONO, HNO3, NH3, SO2, DMS, Biogenic VOC, O-3, CH4, N2O and particles i

  11. GNSS space-time interference mitigation and attitude determination in the presence of interference signals.

    Science.gov (United States)

    Daneshmand, Saeed; Jahromi, Ali Jafarnia; Broumandan, Ali; Lachapelle, Gérard

    2015-05-26

    The use of Space-Time Processing (STP) in Global Navigation Satellite System (GNSS) applications is gaining significant attention due to its effectiveness for both narrowband and wideband interference suppression. However, the resulting distortion and bias on the cross correlation functions due to space-time filtering is a major limitation of this technique. Employing the steering vector of the GNSS signals in the filter structure can significantly reduce the distortion on cross correlation functions and lead to more accurate pseudorange measurements. This paper proposes a two-stage interference mitigation approach in which the first stage estimates an interference-free subspace before the acquisition and tracking phases and projects all received signals into this subspace. The next stage estimates array attitude parameters based on detecting and employing GNSS signals that are less distorted due to the projection process. Attitude parameters enable the receiver to estimate the steering vector of each satellite signal and use it in the novel distortionless STP filter to significantly reduce distortion and maximize Signal-to-Noise Ratio (SNR). GPS signals were collected using a six-element antenna array under open sky conditions to first calibrate the antenna array. Simulated interfering signals were then added to the digitized samples in software to verify the applicability of the proposed receiver structure and assess its performance for several interference scenarios.

  12. GNSS Space-Time Interference Mitigation and Attitude Determination in the Presence of Interference Signals

    Directory of Open Access Journals (Sweden)

    Saeed Daneshmand

    2015-05-01

    Full Text Available The use of Space-Time Processing (STP in Global Navigation Satellite System (GNSS applications is gaining significant attention due to its effectiveness for both narrowband and wideband interference suppression. However, the resulting distortion and bias on the cross correlation functions due to space-time filtering is a major limitation of this technique. Employing the steering vector of the GNSS signals in the filter structure can significantly reduce the distortion on cross correlation functions and lead to more accurate pseudorange measurements. This paper proposes a two-stage interference mitigation approach in which the first stage estimates an interference-free subspace before the acquisition and tracking phases and projects all received signals into this subspace. The next stage estimates array attitude parameters based on detecting and employing GNSS signals that are less distorted due to the projection process. Attitude parameters enable the receiver to estimate the steering vector of each satellite signal and use it in the novel distortionless STP filter to significantly reduce distortion and maximize Signal-to-Noise Ratio (SNR. GPS signals were collected using a six-element antenna array under open sky conditions to first calibrate the antenna array. Simulated interfering signals were then added to the digitized samples in software to verify the applicability of the proposed receiver structure and assess its performance for several interference scenarios.

  13. New Interference Estimation for Power Control in Wireless Networks

    Institute of Scientific and Technical Information of China (English)

    Pyung-soo KIM; Jeong-hun CHOI; Eung-hyuk LEE; Doo-hee JUNG; Eung-tae KIM

    2010-01-01

    This paper proposes new interference estimation for power control in broadband wireless data networks.The proposed approach gives the filtered interference power in real-time removing undesired effects such as the fluctuation of interference power and the measurement noise due to receiver noise.The weli-known Finite Impulse Response (FIR) structrure filter is adopted for both the interference and the noise covariance estimation.The proposed mechanism provides both the filtered interference power and the filtered number of active co-channel interferers,which shows good inherent properties.And the filtered interference power is not affected by the constant number of active co-channel interferes.It is also shown that the filtered number of active co-channel interference is separated from the filtered interference power.From discussions about the choice of design parameters stch as window length and covariance ratio,they can make the estimation performance of the proposed FIR filtering based mechanism as good as possible.Via extensive computer simulations,the performance of of the proposed mechanism is shown to be superior to the existing Kalman filtering based mechanism.

  14. Distributed interference alignment iterative algorithms in symmetric wireless network

    Directory of Open Access Journals (Sweden)

    YANG Jingwen

    2015-02-01

    Full Text Available Interference alignment is a novel interference alignment way,which is widely noted all of the world.Interference alignment overlaps interference in the same signal space at receiving terminal by precoding so as to thoroughly eliminate the influence of interference impacted on expected signals,thus making the desire user achieve the maximum degree of freedom.In this paper we research three typical algorithms for realizing interference alignment,including minimizing the leakage interference,maximizing Signal to Interference plus Noise Ratio (SINR and minimizing mean square error(MSE.All of these algorithms utilize the reciprocity of wireless network,and iterate the precoders between original network and the reverse network so as to achieve interference alignment.We use the uplink transmit rate to analyze the performance of these three algorithms.Numerical simulation results show the advantages of these algorithms.which is the foundation for the further study in the future.The feasibility and future of interference alignment are also discussed at last.

  15. In-flight observations of electromagnetic interferences emitted by satellite

    Institute of Scientific and Technical Information of China (English)

    CAO JinBin; YANG JunYing; YUAN ShiGan; SHEN XuHui; LIU YuanMo; YAN ChunXiao; LI WenZhen; CHEN Tao

    2009-01-01

    Using the data from STAFF/TC-1, this paper for the first time analyzes the electromagnetic interferences of Chinese scientific satellite. The electromagnetic interference of satellite exists mainly below 30 Hz,but can extend to 190 Hz with an obviously decreasing power spectral density. The electromagnetic interferences at frequencies below 190 Hz have good correlation with the solar aspect angle. The electromagnetic interferences at frequencies between 190 and 830 Hz have also correlation with solar aspect angle. However, the electromagnetic interferences at frequencies above 830 Hz have no correlation with the solar aspect angle. The correlation coefficient between solar aspect angel and electromagnetic interferences is around 0.90. The larger the solar aspect angle, the stronger the satellite electromagnetic interference. When the solar aspect angle increases from 90.6° to 93.6°, the electromagnetic interferences at frequencies <10 Hz increase by 8 times and those at frequencies 190-830 Hz increase by 60%. This close association of electromagnetic interferences with the solar aspect angle indicates that the solar aspect angle is the main factor to determine the electromagnetic interferences.The electromagnetic interferences of satellite in sunlight are larger than those in eclipse. The electromagnetic interference produced by solar panel occupies about 87% in the low frequency bend (<100 Hz)and 94% in the high frequency band (>100 Hz) of the total electromagnetic interference produced by satellite. These in flight observations of electromagnetic radiation of satellites will be very helpful to the designs of future satellites of space sciences or earthquake sciences.

  16. In-flight observations of electromagnetic interferences emitted by satellite

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Using the data from STAFF/TC-1, this paper for the first time analyzes the electromagnetic interferences of Chinese scientific satellite. The electromagnetic interference of satellite exists mainly below 30 Hz, but can extend to 190 Hz with an obviously decreasing power spectral density. The electromagnetic interferences at frequencies below 190 Hz have good correlation with the solar aspect angle. The electromagnetic interferences at frequencies between 190 and 830 Hz have also correlation with solar as-pect angle. However, the electromagnetic interferences at frequencies above 830 Hz have no correlation with the solar aspect angle. The correlation coefficient between solar aspect angel and electromagnetic interferences is around 0.90. The larger the solar aspect angle, the stronger the satellite electromagnetic interference. When the solar aspect angle increases from 90.6° to 93.6°, the electromagnetic interferences at frequencies <10 Hz increase by 8 times and those at frequencies 190―830 Hz increase by 60%. This close association of electromagnetic interferences with the solar aspect angle indicates that the solar aspect angle is the main factor to determine the electromagnetic interferences. The electromagnetic interferences of satellite in sunlight are larger than those in eclipse. The electro-magnetic interference produced by solar panel occupies about 87% in the low frequency band (<100 Hz) and 94% in the high frequency band (>100 Hz) of the total electromagnetic interference produced by satellite. These in flight observations of electromagnetic radiation of satellites will be very helpful to the designs of future satellites of space sciences or earthquake sciences.

  17. Carbon Disulfide (CS2) Interference in Glucose Metabolism from Unconventional Oil and Gas Extraction and Processing Emissions.

    Science.gov (United States)

    Rich, Alisa L; Patel, Jay T; Al-Angari, Samiah S

    2016-01-01

    Carbon disulfide (CS2) has been historically associated with the manufacturing of rayon, cellophane, and carbon tetrachloride production. This study is one of the first to identify elevated atmospheric levels of CS2 above national background levels and its mechanisms to dysregulate normal glucose metabolism. Interference in glucose metabolism can indirectly cause other complications (diabetes, neurodegenerative disease, and retinopathy), which may be preventable if proper precautions are taken. Rich et al found CS2 and 12 associated sulfide compounds present in the atmosphere in residential areas where unconventional shale oil and gas extraction and processing operations were occurring. Ambient atmospheric concentrations of CS2 ranged from 0.7 parts per billion by volume (ppbv) to 103 ppbv over a continuous 24-hour monitoring period. One-hour ambient atmospheric concentrations ranged from 3.4 ppbv to 504.6 ppbv. Using the U.S. Environmental Protection Agency Urban Air Toxic Monitoring Program study as a baseline comparison for atmospheric CS2 concentrations found in this study, it was determined that CS2 atmospheric levels were consistently elevated in areas where unconventional oil and gas extraction and processing occurred. The mechanisms by which CS2 interferes in normal glucose metabolism by dysregulation of the tryptophan metabolism pathway are presented in this study. The literature review found an increased potential for alteration of normal glucose metabolism in viscose rayon occupational workers exposed to CS2. Occupational workers in the energy extraction industry exposed to CS2 and other sulfide compounds may have an increased potential for glucose metabolism interference, which has been an indicator for diabetogenic effect and other related health impacts. The recommendation of this study is for implementation of regular monitoring of blood glucose levels in CS2-exposed populations as a preventative health measure.

  18. Statistics in Atmospheric Science

    OpenAIRE

    Solow, Andrew R.

    2003-01-01

    This paper reviews the use of statistical methods in atmospheric science. The applications covered include the development, assessment and use of numerical physical models of the atmosphere and more empirical analysis unconnected to physical models.

  19. Planetary Atmospheric Electricity

    CERN Document Server

    Leblanc, F; Yair, Y; Harrison, R. G; Lebreton, J. P; Blanc, M

    2008-01-01

    This volume presents our contemporary understanding of atmospheric electricity at Earth and in other solar system atmospheres. It is written by experts in terrestrial atmospheric electricity and planetary scientists. Many of the key issues related to planetary atmospheric electricity are discussed. The physics presented in this book includes ionisation processes in planetary atmospheres, charge generation and separation, and a discussion of electromagnetic signatures of atmospheric discharges. The measurement of thunderstorms and lightning, including its effects and hazards, is highlighted by articles on ground and space based instrumentation, and new missions.Theory and modelling of planetary atmospheric electricity complete this review of the research that is undertaken in this exciting field of space science. This book is an essential research tool for space scientists and geoscientists interested in electrical effects in atmospheres and planetary systems. Graduate students and researchers who are new to t...

  20. Atmospheric Lepton Fluxes

    CERN Document Server

    Gaisser, Thomas K

    2014-01-01

    This review of atmospheric muons and neutrinos emphasizes the high energy range relevant for backgrounds to high-energy neutrinos of astrophysical origin. After a brief historical introduction, the main distinguishing features of atmospheric $\

  1. Mirador - Atmospheric Composition

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth Science data access made simple. Atmospheric Composition is focused on the composition of Earth's atmosphere in relation to climate prediction, solar effects,...

  2. Our shared atmosphere

    Science.gov (United States)

    Our atmosphere is a precious and fascinating resource, providing air to breath, shielding us from harmful ultraviolet radiation (UV), and maintaining a comfortable climate. Since the industrial revolution, people have significantly altered the composition of the atmosphere throu...

  3. Metasurface-Enabled Remote Quantum Interference.

    Science.gov (United States)

    Jha, Pankaj K; Ni, Xingjie; Wu, Chihhui; Wang, Yuan; Zhang, Xiang

    2015-07-10

    An anisotropic quantum vacuum (AQV) opens novel pathways for controlling light-matter interaction in quantum optics, condensed matter physics, etc. Here, we theoretically demonstrate a strong AQV over macroscopic distances enabled by a judiciously designed array of subwavelength-scale nanoantennas-a metasurface. We harness the phase-control ability and the polarization-dependent response of the metasurface to achieve strong anisotropy in the decay rate of a quantum emitter located over distances of hundreds of wavelengths. Such an AQV induces quantum interference among radiative decay channels in an atom with orthogonal transitions. Quantum vacuum engineering with metasurfaces holds promise for exploring new paradigms of long-range light-matter interaction for atom optics, solid-state quantum optics, quantum information processing, etc. PMID:26207477

  4. Narrowband interference parameterization for sparse Bayesian recovery

    KAUST Repository

    Ali, Anum

    2015-09-11

    This paper addresses the problem of narrowband interference (NBI) in SC-FDMA systems by using tools from compressed sensing and stochastic geometry. The proposed NBI cancellation scheme exploits the frequency domain sparsity of the unknown signal and adopts a Bayesian sparse recovery procedure. This is done by keeping a few randomly chosen sub-carriers data free to sense the NBI signal at the receiver. As Bayesian recovery requires knowledge of some NBI parameters (i.e., mean, variance and sparsity rate), we use tools from stochastic geometry to obtain analytical expressions for the required parameters. Our simulation results validate the analysis and depict suitability of the proposed recovery method for NBI mitigation. © 2015 IEEE.

  5. Long working distance incoherent interference microscope

    Science.gov (United States)

    Sinclair, Michael B.; De Boer, Maarten P.

    2006-04-25

    A full-field imaging, long working distance, incoherent interference microscope suitable for three-dimensional imaging and metrology of MEMS devices and test structures on a standard microelectronics probe station. A long working distance greater than 10 mm allows standard probes or probe cards to be used. This enables nanometer-scale 3-dimensional height profiles of MEMS test structures to be acquired across an entire wafer while being actively probed, and, optionally, through a transparent window. An optically identical pair of sample and reference arm objectives is not required, which reduces the overall system cost, and also the cost and time required to change sample magnifications. Using a LED source, high magnification (e.g., 50.times.) can be obtained having excellent image quality, straight fringes, and high fringe contrast.

  6. Interference and diffraction in photoelectron spectra

    Energy Technology Data Exchange (ETDEWEB)

    Decleva, P., E-mail: decleva@univ.trieste.it; Ponzi, A.; Santizo, I.

    2014-08-15

    Highlights: • High energy oscillations in the photoionization cross sections. • Interference and diffraction in molecular photoionization. • Non-stoichiometric cross sections. • Core and valence photoionization cross sections in haloacetylenes. - Abstract: Theoretical calculations are employed to disentangle the effect due to coherent emission from equivalent centres and diffraction from neighbouring inequivalent atoms in core and valence photoelectron spectra. The molecules investigated are mono and disubstituted fluoro and iodo acetylenes, compared to the simple acetylene system. The two effects appear well separated and additive in the core region, with diffraction giving oscillations of smaller amplitude, shorter period, and more strongly damped. Their interplay is more complex in the valence region giving rise to irregular patterns which, although rich in information, are more difficult to analyze. It is shown that the use of an external standard molecule can be profitably used to reveal diffraction patterns in the case where no internal ratio is available.

  7. Electromagnetic interference shielding effectiveness of monolayer graphene.

    Science.gov (United States)

    Hong, Seul Ki; Kim, Ki Yeong; Kim, Taek Yong; Kim, Jong Hoon; Park, Seong Wook; Kim, Joung Ho; Cho, Byung Jin

    2012-11-16

    We report the first experimental results on the electromagnetic interference (EMI) shielding effectiveness (SE) of monolayer graphene. The monolayer CVD graphene has an average SE value of 2.27 dB, corresponding to ~40% shielding of incident waves. CVD graphene shows more than seven times (in terms of dB) greater SE than gold film. The dominant mechanism is absorption rather than reflection, and the portion of absorption decreases with an increase in the number of graphene layers. Our modeling work shows that plane-wave theory for metal shielding is also applicable to graphene. The model predicts that ideal monolayer graphene can shield as much as 97.8% of EMI. This suggests the feasibility of manufacturing an ultrathin, transparent, and flexible EMI shield by single or few-layer graphene. PMID:23085718

  8. Scattering and interference in epitaxial graphene.

    Science.gov (United States)

    Rutter, G M; Crain, J N; Guisinger, N P; Li, T; First, P N; Stroscio, J A

    2007-07-13

    A single sheet of carbon, graphene, exhibits unexpected electronic properties that arise from quantum state symmetries, which restrict the scattering of its charge carriers. Understanding the role of defects in the transport properties of graphene is central to realizing future electronics based on carbon. Scanning tunneling spectroscopy was used to measure quasiparticle interference patterns in epitaxial graphene grown on SiC(0001). Energy-resolved maps of the local density of states reveal modulations on two different length scales, reflecting both intravalley and intervalley scattering. Although such scattering in graphene can be suppressed because of the symmetries of the Dirac quasiparticles, we show that, when its source is atomic-scale lattice defects, wave functions of different symmetries can mix.

  9. Onomastic Interferences in the Language of Migration

    Directory of Open Access Journals (Sweden)

    Ioana Jieanu

    2015-12-01

    Full Text Available In case of bilingual speakers, proper names undergo different transformations, depending on the contextual character of a manifestation of meanings, “the relationship between the proper name and the denoted object being temporary, dependent on the verbal and situational context” (Tomescu 1998: 1. Within the scope of the current economic migration of Romanians to Spain and Italy, the names of Romanian people have undergone various modifications under the influence of Spanish and Italian onomastics. In the present work, the performance of two main tasks is described: an analysis of the interferences which emerge within communication, in case of the proper names of Romanian people who have emigrated to Spain and Italy; and classification of the proper names of new-born children within Romanian families that have settled in these countries.

  10. Generalised cognitive motor interference in multiple sclerosis.

    Science.gov (United States)

    Learmonth, Y C; Pilutti, L A; Motl, R W

    2015-06-01

    Researchers have examined cognitive motor interference (CMI) for lower extremity function in MS, but have not examined this in the upper extremity. This study examined CMI for both lower and upper extremity motor tasks in persons with MS and without MS. Eighty-two persons walked on a GAITRite electronic walkway (velocity) and performed the nine-hole peg test (NHPT, seconds) without (single task) and with a cognitive challenge (dual task). The data were analysed with mixed-factor ANOVA and Pearson correlations. When comparing MS and controls, there were statistical significant and exceptionally large Task main effects on gait velocity (ηp(2)=.41; F1,60=55.78; p.450). CMI occurs in both the lower and upper extremities, and is comparable between persons with and without MS and across MS disability level. PMID:25957651

  11. Biomedical Applications Of Interference Reflection Microscopy

    Science.gov (United States)

    Opas, Michal

    1990-04-01

    The relationship between cell adhesiveness and motility is being studied extensively for its paramount importance in the normal development of an organism and in pathological conditions such as tumour metastasis. Although they have been intensively studied at both the cellular and molecular levels, correlative studies of cell structure and adhesiveness, and the precise determination of cell adhesion to a substratum in living cells have been hampered by the fact that cell adhesion has been very difficult to visualize. Two techniques have emerged recently which have allowed successful visualization of cell adhesion. The most recent one, total internal reflection fluorescence, is technically complicated and thus not widespread and so it will not be dealt with here. The other one is a variant of incident light interferometry of thin layers, known as interference reflection microscopy (IRM).

  12. Grounding and shielding circuits and interference

    CERN Document Server

    Morrison, Ralph

    2016-01-01

    Applies basic field behavior in circuit design and demonstrates how it relates to grounding and shielding requirements and techniques in circuit design This book connects the fundamentals of electromagnetic theory to the problems of interference in all types of electronic design. The text covers power distribution in facilities, mixing of analog and digital circuitry, circuit board layout at high clock rates, and meeting radiation and susceptibility standards. The author examines the grounding and shielding requirements and techniques in circuit design and applies basic physics to circuit behavior. The sixth edition of this book has been updated with new material added throughout the chapters where appropriate. The presentation of the book has also been rearranged in order to reflect the current trends in the field.

  13. Avionics electromagnetic interference immunity and environment

    Science.gov (United States)

    Clarke, C. A.

    1986-01-01

    Aircraft electromagnetic spectrum and radio frequency (RF) field strengths are charted, profiling the higher levels of electromagnetic voltages encountered by the commercial aircraft wiring. Selected military, urban, and rural electromagnetic field levels are plotted and provide a comparison of radiation amplitudes. Low frequency magnetic fields and electric fields from 400 H(Z) power systems are charted versus frequency and wire separation to indicate induced voltages on adjacent or neighboring circuits. Induced EMI levels and attenuation characteristics of electric, magnetic, RF fields, and transients are plotted and graphed for common types of wire circuits. The significance of wire circuit returns and shielding is emphasized to highlight the techniques that help block the paths of electromagnetic interference and maintain avionic interface signal quality.

  14. Increased Stroop interference with better second-language reading skill.

    Science.gov (United States)

    Braet, Wouter; Noppe, Nele; Wagemans, Johan; Op de Beeck, Hans

    2011-03-01

    Skilled readers demonstrate remarkable efficiency in processing written words, unlike beginning readers for whom reading occurs more serially and places higher demands on visual attention. In the present study, we used the Stroop paradigm to investigate the relationship between reading skill and automaticity, in individuals learning a second language with a different orthographic system. Prior studies using this paradigm have presented a mixed picture, finding a positive, a negative, or no relationship between the size of Stroop interference and reading skills. Our results show that Stroop interference in the second language was positively related to reading skill (when controlled for interference in the first language). Furthermore, interference was positively related to objective but not subjective indices of the amount of exposure to the second language. We suggest that the lack of consistency in the results of earlier studies may be due, at least in part, to these studies looking at Stroop interference in isolation, rather than comparing interference between languages.

  15. Abstract Certification of Global Non-Interference in Rewriting Logic

    CERN Document Server

    Alba-Castro, Mauricio; Escobar, Santiago

    2010-01-01

    Non-interference is a semantic program property that assigns confidentiality levels to data objects and prevents illicit information flows from occurring from high to low security levels. In this paper, we present a novel security model for global non-interference which approximates non-interference as a safety property. We also propose a certification technique for global non-interference of complete Java classes based on rewriting logic, a very general logical and semantic framework that is efficiently implemented in the high-level programming language Maude. Starting from an existing Java semantics specification written in Maude, we develop an extended, information-flow Java semantics that allows us to correctly observe global non-interference policies. In order to achieve a finite state transition system, we develop an abstract Java semantics that we use for secure and effective non-interference Java analysis. The analysis produces certificates that are independently checkable and are small enough to be u...

  16. Cognitive Aware Interference Mitigation Scheme for LTE Femtocells

    KAUST Repository

    AlQerm, Ismail

    2015-04-21

    Femto-cells deployment in today’s cellular networks came into practice to fulfill the increasing demand for data services. However, interference to other femto and macro-cells users remains an unresolved challenge. In this paper, we propose an interference mitigation scheme to control the cross-tier interference caused by femto-cells to the macro users and the co-tier interference among femtocells. Cognitive radio spectrum sensing capability is utilized to determine the non-occupied channels or the ones that cause minimal interference to the macro users. An awareness based channel allocation scheme is developed with the assistance of the graph-coloring algorithm to assign channels to the femto-cells base stations with power optimization, minimal interference, maximum throughput, and maximum spectrum efficiency. In addition, the scheme exploits negotiation capability to match traffic load and QoS with the channel capacity, and to maintain efficient utilization of the available channels.

  17. Affective privilege: Asymmetric interference by emotional distracters

    Directory of Open Access Journals (Sweden)

    Crystal eReeck

    2011-09-01

    Full Text Available Numerous theories posit that affectively salient stimuli are privileged in their capacity to capture attention and disrupt ongoing cognition. Two underlying assumptions in this theoretical position are that the potency of affective stimuli transcends task boundaries (i.e., emotional distracters do not have to belong to a current task-set to disrupt processing and that there is an asymmetry between emotional and cognitive processing (i.e., emotional distracters disrupt cognitive processing, but not vice versa. These assumptions have remained largely untested, as common experimental probes of emotion-cognition interaction rarely manipulate task-relevance and only examine one side of the presumed asymmetry of interference. To test these propositions directly, a face-word Stroop protocol was adapted to independently manipulate (a the congruency between target and distracter stimulus features, (b the affective salience of distracter features, and (c the task-relevance of emotional compared to non-emotional target features. A three-way interaction revealed interdependent effects of distracter relevance, congruence, and affective salience. Compared to task-irrelevant distracters, task-relevant congruent distracters facilitated performance and task-relevant incongruent distracters impaired performance, but the latter effect depended on the nature of the target feature and task. Specifically, task-irrelevant emotional distracters resulted in equivalent performance costs as task-relevant non-emotional distracters, whereas task-irrelevant non-emotional distracters did not produce performance costs comparable to those generated by task-relevant emotional distracters. These results document asymmetric cross-task interference effects for affectively salient stimuli, supporting the notion of affective prioritization in human information processing.

  18. Atmospheric refraction : a history

    NARCIS (Netherlands)

    Lehn, WH; van der Werf, S

    2005-01-01

    We trace the history of atmospheric refraction from the ancient Greeks up to the time of Kepler. The concept that the atmosphere could refract light entered Western science in the second century B.C. Ptolemy, 300 years later, produced the first clearly defined atmospheric model, containing air of un

  19. Interference in wireless ad hoc networks with smart antennas

    KAUST Repository

    Alabdulmohsin, Ibrahim

    2014-08-01

    In this paper, we show that the use of directional antennas in wireless ad hoc networks can actually increase interference due to limitations of virtual carrier sensing. We derive a simple mathematical expression for interference in both physical and virtual carrier sense networks, which reveals counter-intuitively that receivers in large dense networks with directional antennas can experience larger interference than in omnidirectional networks unless the beamwidth is sufficiently small. Validity of mathematical analysis is confirmed using simulations.

  20. Interference cancellation technique under imperfect synchronization in cellular systems

    Institute of Scientific and Technical Information of China (English)

    WANG; Xin; WU; Zhuo

    2009-01-01

    In this paper, an asynchronous cooperative cellular system applied with space-time block coding(STBC)is investigated. A signal detector is proposed based on parallel interference cancellation(PIC), to cancel the inter-symbol interference(ISI)caused by the imperfect synchronization. Simulation results show that the proposed PIC detector can effectively suppress the ISI, but there is still a comparatively high error floor, due to the co-channel interference(CCI)of the cellular system.

  1. Interference with follicle stimulating hormone regulation of human ovarian function

    OpenAIRE

    Fauser, Bart

    1996-01-01

    textabstractThis review summarizes observations on the background and potential clinical significance of interference with follicle stimulating hormone (FSH) regulation of human ovarian function. This interference may occur at the level of the pituitary by the secretion of FSH isoforms with reduced or absent bioactivity. In addition, interference with FSH may occur in the circulation, or within the ovarian follicular compartment. Although the full range of its significance remains to be eluci...

  2. Compute-and-Forward: Harnessing Interference through Structured Codes

    OpenAIRE

    Nazer, Bobak; Gastpar, Michael C.

    2009-01-01

    Abstract—Interference is usually viewed as an obstacle to communication in wireless networks. This paper proposes a new strategy, compute-and-forward, that exploits interference to obtain significantly higher rates between users in a network. The key idea is that relays should decode linear functions of transmitted messages according to their observed channel coefficients rather than ignoring the interference as noise. After decoding these linear equations, the relays simply send them t...

  3. Minimizing interference in automotive radar using digital beamforming

    OpenAIRE

    C. Fischer; M. Goppelt; Blöcher, H.-L.; Dickmann, J.

    2011-01-01

    Millimetre wave radar is an essential part of automotive safety functions. A high interference tolerance, especially with other radar sensors, is vital. This paper gives an overview of the motivation, the boundary conditions and related activities in the MOSARIM project funded by the European Union and concerned with interference mitigation in automotive radars. Current and planned activities considering Digital Beamforming (DBF) as a method for interference mitigation are p...

  4. Two-photon Interference with Non-identical Photons

    CERN Document Server

    Liu, Jianbin; Zheng, Huaibin; Chen, Hui; Li, Fu-Li; Xu, Zhuo

    2014-01-01

    The indistinguishability of non-identical photons is dependent on detection system in quantum physics. If two photons with different wavelengths are indistinguishable for a detection system, there can be two-photon interference when these two photons are incident to two input ports of a Hong-Ou-Mandel interferometer, respectively. The reason why two-photon interference phenomena are different for classical and nonclassical light is not due to interference, but due to the properties of light and detection system. These conclusions are helpful to understand the physics and applications of two-photon interference.

  5. On the Beamforming Design for Efficient Interference Alignment

    CERN Document Server

    Choi, Sang Won; Chung, Sae-Young

    2009-01-01

    An efficient interference alignment (IA) scheme is developed for $K$-user single-input single-output frequency selective fading interference channels. The main idea is to steer the transmit beamforming matrices such that at each receiver the subspace dimensions occupied by interference-free desired streams are asymptotically the same as those occupied by all interferences. Our proposed scheme achieves a higher multiplexing gain at any given number of channel realizations in comparison with the original IA scheme, which is known to achieve the optimal multiplexing gain asymptotically.

  6. Cognitive interference modeling with applications in power and admission control

    KAUST Repository

    Mahmood, Nurul Huda

    2012-10-01

    One of the key design challenges in a cognitive radio network is controlling the interference generated at coexisting primary receivers. In order to design efficient cognitive radio systems and to minimize their unwanted consequences, it is therefore necessary to effectively control the secondary interference at the primary receivers. In this paper, a generalized framework for the interference analysis of a cognitive radio network where the different secondary transmitters may transmit with different powers and transmission probabilities, is presented and various applications of this interference model are demonstrated. The findings of the analytical performance analyses are confirmed through selected computer-based Monte-Carlo simulations. © 2012 IEEE.

  7. An Anti-Interference Coding in UWB-OFDM Communications

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shi-bing; CAO Shi-ke; ZHANG Li-jun

    2005-01-01

    An anti-interference orthogonal coding is introduced based on Hadamard code and Orthogonal Frequency-Division Multiplexing (OFDM), in which all sub-channels of Ultra-WideBand (UWB) system are divided into M sub-bands and the power of the every transmitted symbol spreads over each of the sub-bands rather than one sub-band. The complete mathematical analytical relation between encoding and decoding is present and the robustness of the system to interference is examined. When some sub-channels are affected by interference or jamming, the system could regenerate the symbol from others. Simulation results show that the Anti-Interference UWB-OFDM (AI-OFDM) system has evident advantages over conventional UWB-OFDM systems as well as the Interference Suppressing UWB-OFDM (IS-OFDM) in Bit Error Rate (BER) thanks to its robustness to interference. In the case of bad interference, the AI-OFDM system could work up to snuff without any anti-interference step, but the conventional UWB-OFDM system couldn't. Compared with the IS-OFDM system, the AI-OFDM system improves the performance about 5 dB in Signal-to-Interference Ratio (SIR) and the order of 1~2 in BER.

  8. The right posterior paravermis and the control of language interference.

    Science.gov (United States)

    Filippi, Roberto; Richardson, Fiona M; Dick, Frederic; Leech, Robert; Green, David W; Thomas, Michael S C; Price, Cathy J

    2011-07-20

    Auditory and written language in humans' comprehension necessitates attention to the message of interest and suppression of interference from distracting sources. Investigating the brain areas associated with the control of interference is challenging because it is inevitable that activation of the brain regions that control interference co-occurs with activation related to interference per se. To isolate the mechanisms that control verbal interference, we used a combination of structural and functional imaging techniques in Italian and German participants who spoke English as a second language. First, we searched structural MRI images of Italian participants for brain regions in which brain structure correlated with the ability to suppress interference from the unattended dominant language (Italian) while processing heard sentences in their weaker language (English). This revealed an area in the posterior paravermis of the right cerebellum in which gray matter density was higher in individuals who were better at controlling verbal interference. Second, we found functional activation in the same region when our German participants made semantic decisions on written English words in the presence of interference from unrelated words in their dominant language (German). This combination of structural and functional imaging therefore highlights the contribution of the right posterior paravermis to the control of verbal interference. We suggest that the importance of this region for language processing has previously been missed because most fMRI studies limit the field of view to increase sensitivity, with the lower part of the cerebellum being the region most likely to be excluded.

  9. Neural basis of semantic and syntactic interference in sentence comprehension.

    Science.gov (United States)

    Glaser, Yi G; Martin, Randi C; Van Dyke, Julie A; Hamilton, A Cris; Tan, Yingying

    2013-09-01

    According to the cue-based parsing approach (Lewis, Vasishth, & Van Dyke, 2006), sentence comprehension difficulty derives from interference from material that partially matches syntactic and semantic retrieval cues. In a 2 (low vs. high semantic interference)×2 (low vs. high syntactic interference) fMRI study, greater activation was observed in left BA44/45 for high versus low syntactic interference conditions following sentences and in left BA45/47 for high versus low semantic interference conditions following comprehension questions. A conjunction analysis showed BA45 associated with both types of interference, while BA47 was associated with only semantic interference. Greater activation was also observed in the left STG in the high interference conditions. Importantly, the results for the LIFG could not be attributed to greater working memory capacity demands for high interference conditions. The results favor a fractionation of the LIFG wherein BA45 is associated with post-retrieval selection and BA47 with controlled retrieval of semantic information.

  10. 47 CFR 101.509 - Interference protection criteria.

    Science.gov (United States)

    2010-10-01

    ..., and radiation pattern of the transmitting and receiving antennas. Licensees are expected to cooperate fully in attempting to resolve problems of potential interference before bringing the matter to...

  11. Note: Interference effects elimination in wave plates manufacture.

    Science.gov (United States)

    Chen, Wenxue; Zhang, Shulian; Long, Xingwu

    2013-01-01

    Wave plate manufacturing precision is critical to the functionality of the instruments that use these wave plates among their optical components. In current manufacturing processes, the optical interference effects of the wave plate affect the manufacturing precision of the plate itself. To manufacture high-precision wave plates, we have researched the physical mechanism of these interference effects theoretically. Based on our analysis, an interference effects elimination structure is proposed that will allow us to ignore the interference effects of the wave plate. On the basis of this work, the precision of manufacture can be improved greatly.

  12. Adaptive cancellation of Es layer interference using auxiliary horizontal antennas

    Institute of Scientific and Technical Information of China (English)

    Zhao Long; Zhang Ning

    2006-01-01

    Based on a dual-polarization high-frequency wave radar system, an adaptive system using horizontal antennas for the suppression of the Es layer interference (ELI) is described. The data received from the horizontal antennas were correlated with the data received from the Vertically Polarized Antennas (VPAs) to estimate and cancel the interference adaptively in the VPAs. Suppressing the interference after each coherent integration time interval, about 25 dB signal-to-interference ratio is expected with the experimentally derived data.

  13. Adaptive Radio Frequency Interference Mitigation for HF Surface Wave Radar

    Institute of Scientific and Technical Information of China (English)

    WAN Xian-rong; KE Heng-yu; CHENG Feng

    2005-01-01

    The paper analyses the characteristics of radio frequency interference (RFI) in HF surface wave radar (HFSWR) which adopts the linear frequency modulated interrupted continuous wave (FMICW). RFI will influence all the range cells including all the positive frequency and negative frequency, and the negative frequency range cells contain only the interference information. Based on the above characteristics, we introduce and analyze a new adaptive interference mitigation beamforming algorithm using the negative frequency range cells samples to estimate the interference covariance matrix. Experimental results confirm that this general and robust algorithm can achieve effective RFI suppression using the data recorded by the HFSWR, located near Zhoushan in Zhejiang China.

  14. Interference susceptibility measurements for an MSK satellite communication link

    Science.gov (United States)

    Kerczewski, Robert J.; Fujikawa, Gene

    1992-01-01

    The results are presented of measurements of the degradation of an MSK satellite link due to modulated and CW (unmodulated) interference. These measurements were made using a hardware based satellite communication link simulator at NASA-Lewis. The results indicate the amount of bit error rate degradation caused by CW interference as a function of frequency and power level, and the degradation caused by adjacent channel and cochannel modulated interference as a function of interference power level. Results were obtained for both the uplink case (including satellite nonlinearity) and the downlink case (linear channel).

  15. Interference checking approach with tolerance based on assembly dimension chain

    Institute of Scientific and Technical Information of China (English)

    Wang Lei; Li Yingguang; Wang Wei; and Liao Wenhe

    2012-01-01

    CAD model with nominal dimension is implemented in interference checking of assembly simulation of aircraft complex parts at present, which causes inadequate availability. In order to address this challenging issue, interference checking method with tolerance based on assembly dimension chain was proposed. Worst case and maximum error probability of tolerance of composing loop were used, and CAD models were respectively re-constructed and inserted into simulation system. Before dynamic interference checking, engineering semantic interference condition was set to assembly requirements. Finally, the interface checking result was a basis for reasonability of assembly process and tolerance. A prototype system was developed based on the above research.

  16. Two-photon interference with non-identical photons

    Science.gov (United States)

    Liu, Jianbin; Zhou, Yu; Zheng, Huaibin; Chen, Hui; Li, Fu-li; Xu, Zhuo

    2015-11-01

    Two-photon interference with non-identical photons is studied based on the superposition principle in Feynman's path integral theory. The second-order temporal interference pattern is observed by superposing laser and pseudothermal light beams with different spectra. The reason why there is two-photon interference for photons of different spectra is that non-identical photons can be indistinguishable for the detection system when Heisenberg's uncertainty principle is taken into account. These studies are helpful to understand the second-order interference of light in the language of photons.

  17. Nonisothermal Pluto atmosphere models

    International Nuclear Information System (INIS)

    The present thermal profile calculation for a Pluto atmosphere model characterized by a high number fraction of CH4 molecules encompasses atmospheric heating by solar UV flux absorption and conductive transport cooling to the surface of Pluto. The stellar occultation curve predicted for an atmosphere of several-microbar surface pressures (which entail the existence of a substantial temperature gradient close to the surface) agrees with observations and implies that the normal and tangential optical depth of the atmosphere is almost negligible. The minimum period for atmospheric methane depletion is calculated to be 30 years. 29 refs

  18. A New Outer Bound and the Noisy-Interference Sum-Rate Capacity for Gaussian Interference Channels

    CERN Document Server

    Shang, Xiaohu; Chen, Biao

    2007-01-01

    A new outer bound on the capacity region of Gaussian interference channels is developed. The bound combines and improves existing genie-aided methods and is shown to give the sum-rate capacity for noisy interference as defined in this paper. Specifically, it is shown that if the channel coefficients and power constraints satisfy a simple condition then single-user detection at each receiver is sum-rate optimal, i.e., treating the interference as noise incurs no loss in performance. This is the first concrete (finite signal-to-noise ratio) capacity result for the Gaussian interference channel with weak to moderate interference. Furthermore, for certain mixed (weak and strong) interference scenarios, the new outer bounds give a corner point of the capacity region.

  19. Reconstruction of Interfering Waves from Three Dimensional Analysis of Their Interference Pattern

    Directory of Open Access Journals (Sweden)

    M. T. Tavassoli

    1997-04-01

    Full Text Available   Optical interferometry is being used as an efficient tool to analyse smooth surfaces for more than a century. Although, due to introduction of novel computer assisted analyzing techniques and array detectors, like CCD, the speed and the precision of processing have been increased tremendously, but the main equation involved is not changed. The main equation is the intensity distribution in the interference pattern of a plane reference wave and the required wave.   In the paper it is shown that by analysis of the interference pattern of two unknown waves in three dimension (which is possible for coherent waves it is possible to reconstruct each wave separately. This approach has several useful applications, namely, on can do without reference plane wave in the interferometric surface analysis and, it is possible to reconstruct an unknown wave by making it to interfere with itself. This is very useful in determining the profile of laser beams and erasing the effect of atmospheric disturbances on observing astronomical objects.

  20. RNA Interference in the Age of CRISPR: Will CRISPR Interfere with RNAi?

    OpenAIRE

    Unnikrishnan Unniyampurath; Rajendra Pilankatta; Krishnan, Manoj N.

    2016-01-01

    The recent emergence of multiple technologies for modifying gene structure has revolutionized mammalian biomedical research and enhanced the promises of gene therapy. Over the past decade, RNA interference (RNAi) based technologies widely dominated various research applications involving experimental modulation of gene expression at the post-transcriptional level. Recently, a new gene editing technology, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and the CRISPR-associa...

  1. A novel interference suppression scheme for narrowband interference in satellite communication systems

    Science.gov (United States)

    Liu, Heng; Xia, Caijie; Zhou, Ronghua

    2007-11-01

    Narrowband interference (NBI) is familiar in satellite DS/CDMA systems. Frequency domain notch filter (FDNF) based on FFT was popular due to its fast arithmetic and absence of convergence time and recursive algorithm. However, at low jammer-to-signal (JSR), the bit error rate (BER) performance degrades dramatically in comparison with the matched filter (MF) receiver of the system self. In this paper, a switching metric named compression gain (CG) was introduced to force FDNF active only after certain interference power level and MF receiver active at lower JSR. By use of CG switching metric, the algorithm overcomes the threshold effect of traditional FDNF. The advantages of the improved FDNF (IFDNF) are low computational complexity and expandability due to that the decision of the domain to be used is made before the interference suppression and the inverse transform. The IFDNF based on CG metric offers better BER performance than original FDNF at lower JSR, and also outperforms the MF receiver at higher JSR. Numerical simulation results show the proposed IFDNF overcomes the threshold effect flaw and also verify the validity of the CG parameter as a switching metric.

  2. Carbon cycle and climate commitments from early human interference

    Science.gov (United States)

    Zickfeld, K.; Solomon, S.

    2015-12-01

    According to the early anthropogenic hypothesis proposed by Ruddiman (2003), human influence on Earth's climate began several thousand years before the beginning of the industrial era. Agriculture and deforestation starting around 8000 years before present (BP) and slowly increasing over the Holocene, would have led to an increase in atmospheric methane (CH4) and carbon dioxide (CO2) concentration, preventing a natural cooling of Earth's climate. Here, the emphasis is not on testing Ruddiman's hypothesis, but rather on exploring the carbon cycle and climate commitment from potential early CH4 and CO2 emissions. In contrast to modern greenhouse gas emissions, early emissions occurred over millennia, allowing the climate system to come to near-equilibrium with the applied forcing. We perform two transient Holocene simulations with an Earth system model of intermediate complexity - the University of Victoria Earth System Climate Model (UVic ESCM). The first simulation is a standard transient Holocene simulation, forced with reconstructed changes in CO2 and CH4 concentrations and orbital and volcanic forcing. The second simulation is forced with CO2 and CH4 concentrations corrected for the net anthropogenic contribution postulated by Ruddiman (2007), with other forcings evolving as in the standard simulation. The difference in diagnosed emissions between the two simulations allows us to determine the anthropogenic emissions. After year 1850, anthropogenic CO2 and CH4 emissions are set to zero and the simulations continued for several hundred years. In this paper, we analyze the carbon cycle and climate response to the applied forcings, and quantify the resulting (post 1850) commitment from early anthropogenic interference.

  3. An experimental investigation on wind turbine aeromechanics and wake interferences among multiple wind turbines

    Science.gov (United States)

    Ozbay, Ahmet

    A comprehensive experimental study was conducted to investigate wind turbine aeromechanics and wake interferences among multiple wind turbines sited in onshore and offshore wind farms. The experiments were carried out in a large-scale Aerodynamic/Atmospheric Boundary Layer (AABL) Wind Tunnel available at Iowa State University. An array of scaled three-blade Horizontal Axial Wind Turbine (HAWT) models were placed in atmospheric boundary layer winds with different mean and turbulence characteristics to simulate the situations in onshore and offshore wind farms. The effects of the important design parameters for wind farm layout optimization, which include the mean and turbulence characteristics of the oncoming surface winds, the yaw angles of the turbines with respect to the oncoming surface winds, the array spacing and layout pattern, and the terrain topology of wind farms on the turbine performances (i.e., both power output and dynamic wind loadings) and the wake interferences among multiple wind turbines, were assessed in detail. The aeromechanic performance and near wake characteristics of a novel dual-rotor wind turbine (DRWT) design with co-rotating or counter-rotating configuration were also investigated, in comparison to a conventional single rotor wind turbine (SRWT). During the experiments, in addition to measuring dynamic wind loads (both forces and moments) and the power outputs of the scaled turbine models, a high-resolution Particle Image Velocity (PIV) system was used to conduct detailed flow field measurements (i.e., both free-run and phase-locked flow fields measurements) to reveal the transient behavior of the unsteady wake vortices and turbulent flow structures behind wind turbines and to quantify the characteristics of the wake interferences among the wind turbines sited in non-homogenous surface winds. A miniature cobra anemometer was also used to provide high-temporal-resolution data at points of interest to supplement the full field PIV

  4. Wavefront dislocations of Gaussian beams nesting optical vortices in a turbulent atmosphere

    Institute of Scientific and Technical Information of China (English)

    Yixin Zhang(张逸新); Chunkan Tao(陶纯堪)

    2004-01-01

    A phase singularity of the light field created by interference of two Gaussian singular beams which propagate in a weak and near ground turbulent atmosphere is analyzed by the Rytov approximation and the short-term averaging method of the dislocation-position. We demonstrate that an edge or circular dislocation may be formed by both parallel and coaxial or noncoaxial collimated beams with different or equal beam-width interfere. The edge or circular short-term wavefront dislocations of super position field depend on the atmospheric turbulence strength, beam propagation distance, amplitude ratio, dislocation of nesting vortices, and beam-width or beam-width ratio of the individual beams.

  5. Atmospheric Channel Characteristics for Quantum Communication with Continuous Polarization Variables

    CERN Document Server

    Heim, Bettina; Bartley, Tim; Sabuncu, Metin; Wittmann, Christoffer; Sych, Denis; Marquardt, Christoph; Leuchs, Gerd

    2009-01-01

    We investigate the properties of an atmospheric channel for free space quantum communication with continuous polarization variables. In our prepare-and-measure setup, coherent polarization states are transmitted through an atmospheric quantum channel of 100m length on the roof of our institute's building. The signal states are measured by homodyne detection with the help of a local oscillator (LO) which propagates in the same spatial mode as the signal, orthogonally polarized to it. Thus the interference of signal and LO is excellent and atmospheric fluctuations are autocompensated. The LO also acts as spatial and spectral filter, which allows for unrestrained daylight operation. Important characteristics for our system are atmospheric channel influences that could cause polarization, intensity and position excess noise. Therefore we study these influences in detail. Our results indicate that the channel is suitable for our quantum communication system in most weather conditions.

  6. THE IMPACT OF QUANTUM INTERFERENCE BETWEEN DIFFERENT J-LEVELS ON SCATTERING POLARIZATION IN SPECTRAL LINES

    Energy Technology Data Exchange (ETDEWEB)

    Belluzzi, Luca; Bueno, Javier Trujillo [Instituto de Astrofisica de Canarias, E-38205 La Laguna, Tenerife (Spain)

    2011-12-10

    The spectral line polarization produced by optically pumped atoms contains a wealth of information on the thermal and magnetic structure of a variety of astrophysical plasmas, including that of the solar atmosphere. A correct decoding of such information from the observed Stokes profiles requires a clear understanding of the effects that radiatively induced quantum interference (or coherence) between pairs of magnetic sublevels produces on these observables, in the absence of and in the presence of magnetic fields of arbitrary strength. Here we present a detailed theoretical investigation of the role of coherence between pairs of sublevels pertaining to different fine-structure J-levels, clarifying when it can be neglected for facilitating the modeling of the linear polarization produced by scattering processes in spectral lines. To this end, we apply the quantum theory of spectral line polarization and calculate the linear polarization patterns of the radiation scattered at 90 Degree-Sign by a slab of stellar atmospheric plasma, both taking into account and neglecting the above-mentioned quantum interference. Particular attention is given to the {sup 2}S - {sup 2}P, {sup 5}S - {sup 5}P, and {sup 3}P - {sup 3}S multiplets. We point out the observational signatures of this kind of interference and analyze its sensitivity to the energy separation between the interfering levels, to the amount of emissivity in the background continuum radiation, to lower-level polarization, and to the presence of a magnetic field. Some interesting applications to the following spectral lines are also presented: Ca II H and K, Mg II h and k, Na I D{sub 1} and D{sub 2}, the Ba II 4554 #Angstrom# and 4934 #Angstrom# resonance lines, the Cr I triplet at 5207 #Angstrom#, the O I triplet at 7773 #Angstrom#, the Mg I b-lines, and the H{alpha} and Ly{alpha} lines of H I.

  7. Direct laser interference patterning of polystyrene films doped with azo dyes, using 355 nm laser light

    Energy Technology Data Exchange (ETDEWEB)

    Broglia, M.F. [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina); Saarland University, Department of Materials Science, Campus, D-66123 Saarbrücken (Germany); Suarez, S.; Soldera, F.; Mücklich, F. [Saarland University, Department of Materials Science, Campus, D-66123 Saarbrücken (Germany); Barbero, C.A.; Bellingeri, R.; Alustiza, F. [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina); Acevedo, D., E-mail: dacevedo@exa.unrc.edu.ar [Universidad Nacional de Río Cuarto, Departamento de Química, Ruta 36 km 601, Río Cuarto, Córdoba 5800 (Argentina)

    2014-05-01

    Highlights: • We describe the first use of Direct Laser Interference Patterning on PS at 355 nm. . • The structured areas of regular lines are produced in several square millimeters. • The method, Direct Laser Interference Patterning (DLIP) uses a single laser pulse. • DLIP is applied at room temperature and atmospheric pressure. • DLIP is easier to use than other lithographic techniques. • The topography contrasts with the usual Polystyrene ablation at lower wavelengths. - Abstract: The generation of line-like periodic patterns by direct laser interference patterning (DLIP) of polystyrene films (PS) at a wavelength of 355 nm has been investigated. No structuration is achieved in plain PS due to the weak absorption of the polymer at 355 nm. On the other hand, patterning is achieved on films doped (PSd) with an azo dye (2-anisidine → 2-anisidine) which is incorporated in the polymer solution used for film preparation. Periodic micro-structures are generated. DLIP on PSd results in the swelling of the surface at low fluences, while at high laser intensities it causes the ablation of the regions at the interference maxima positions. The results contrast with the usual process of DLIP on PS (at shorter wavelengths, like 266 nm) where only ablation is detected. The results suggest that decomposition of the azo dye is the driving force of the patterning which therefore differ from the patterning obtained when plain PS is irradiated with laser light able to be absorbed by the aromatic ring in PS (e.g. 266 nm). The biocompatibility of these materials and adhesion of cells was tested, the data from in vitro assays shows that fibroblast cells are attached and proliferate extensively on the PSd films.

  8. Interference Effects in Bimanual Coordination Are Independent of Movement Type

    Science.gov (United States)

    Calvin, Sarah; Huys, Raoul; Jirsa, Viktor K.

    2010-01-01

    Simultaneously executed limb movements interfere with each other. Whereas the interference between discrete movements is examined mostly from a cognitive perspective, that between rhythmic movements is studied mainly from a dynamical systems perspective. As the tools and concepts developed by both communities are limited in their applicability to…

  9. Interference Reconsidered: The Role of Similarity in Second Language Acquisition.

    Science.gov (United States)

    Young-Scholten, Martha

    1985-01-01

    The validity of the theory of crucial similarity in language interference is investigated. The theory proposes that when a first and a second language are structurally similar in some aspects, the second language learner will assume similarity in other aspects, causing interference. In this study, the German of first grade students whose teacher…

  10. Transparency induced by two photon interference in a beam splitter

    Institute of Scientific and Technical Information of China (English)

    Wang Kai-Ge; Yang Guo-Jian

    2004-01-01

    We propose a special two-photon state which is completely transparent in a 50/50 beam splitter. This effect is caused by the destructive two-photon interference and shows the signature of photon entanglement. We find that the symmetry of the two-photon spectrum plays the key role for the properties of two-photon interference.

  11. Optical interference coatings for optics and photonics [Invited].

    Science.gov (United States)

    Lee, Cheng-Chung

    2013-01-01

    Optical interference coatings play as an important role in the progress in optics and photonics. In this article we give a minireview of the evolution of optical interference coatings from the theory, the design, to the manufacture. Some interesting but challenging topics for the future are also discussed.

  12. Quantum interference and diffraction of parametric down-converted biphotons

    Indian Academy of Sciences (India)

    Ryosuke Shimizu; Keiichi Edamatsu; Tadashi Itoh

    2002-08-01

    We present two-photon diffraction and interference experiments utilizing parametric down-converted photon pairs (biphotons) and a transmission grating. The biphoton exhibits a diffraction-interference pattern equivalent to an effective single particle with half wavelength of the constituent photons.

  13. Effect of Auditory Interference on Memory of Haptic Perceptions.

    Science.gov (United States)

    Anater, Paul F.

    1980-01-01

    The effect of auditory interference on the processing of haptic information by 61 visually impaired students (8 to 20 years old) was the focus of the research described in this article. It was assumed that as the auditory interference approximated the verbalized activity of the haptic task, accuracy of recall would decline. (Author)

  14. Interference Impacts Working Memory in Mild Cognitive Impairment

    Science.gov (United States)

    Aurtenetxe, Sara; García-Pacios, Javier; del Río, David; López, María E.; Pineda-Pardo, José A.; Marcos, Alberto; Delgado Losada, Maria L.; López-Frutos, José M.; Maestú, Fernando

    2016-01-01

    Mild cognitive impairment (MCI) is considered a transitional stage between healthy aging and dementia, specifically Alzheimer's disease (AD). The most common cognitive impairment of MCI includes episodic memory loss and difficulties in working memory (WM). Interference can deplete WM, and an optimal WM performance requires an effective control of attentional resources between the memoranda and the incoming stimuli. Difficulties in handling interference lead to forgetting. However, the interplay between interference and WM in MCI is not well-understood and needs further investigation. The current study investigated the effect of interference during a WM task in 20 MCIs and 20 healthy elder volunteers. Participants performed a delayed match-to-sample paradigm which consisted in two interference conditions, distraction and interruption, and one control condition without any interference. Results evidenced a disproportionate impact of interference on the WM performance of MCIs, mainly in the presence of interruption. These findings demonstrate that interference, and more precisely interruption, is an important proxy for memory-related deficits in MCI. Thus, the current findings reveal novel evidence regarding the causes of WM forgetting in MCI patients, associated with difficulties in the mechanisms of attentional control. PMID:27790082

  15. FUNGICIDAL INTERFERENCE DURING INFECTION RELATED DEVELOPMENTAL STAGES INMAGNAPORTHE GRISEA

    Directory of Open Access Journals (Sweden)

    Anil S. Kotasthane

    2012-12-01

    Full Text Available Rice blast, a serious epidemic disease that limits grain yield worldwide is caused by fungal pathogen Magnaporthe grisea. The present investigation was carried out to identify the probable avenues of interference by different fungicides during the critical stages of infection related morphogenesis of M. grisea. Effect of six fungicides at different stages of infection related morphogenesis showed variable results like interference in conidial germination, distortion of surface structure of the spores,  interference in the germ tube elongation, interference in the transfer of the cell contents from spore to appresorrium, deformity in appressorial dome, interference in the melanin deposition. We speculate the critical stages at which these fungicides may interfere. The activity of immunosuppressive drug cyclosporin A (CsA which is a potential antifungal agent was equated with all the fungicides used. We hypothesize that the exposure of the M. grisea spore to the fungicide may lead to the formation of a cyclophilin CYP1-fungicide complex, which inactivates calcineurin and prevents calcium/ calmodulin-dependent protein phosphatase signaling and is therefore one of the target of fungicidal interference. An understanding of how fungal pathogens break the protective barrier that comprise the surface of the host plant as well as precise identification of avenues of fungicidal interference during infection related development in M. grisea will lead to novel approach for controlling plant diseases.

  16. Breakdown of interference rules in azulene, a nonalternant hydrocarbon

    DEFF Research Database (Denmark)

    Xia, Jianlong; Capozzi, Brian; Wei, Sujun;

    2014-01-01

    interference characteristics of nonalternant hydrocarbons. As an exemplary case, we show that azulene derivatives that are predicted to exhibit destructive interference based on widely accepted atom-counting models show a significant conductance at low biases. Although simple models to predict the low...

  17. AKSATINT - SATELLITE INTERFERENCE ANALYSIS AND SIMULATION USING PERSONAL COMPUTERS

    Science.gov (United States)

    Kantak, A.

    1994-01-01

    In the late seventies, the number of communication satellites in service increased, and interference has become an increasingly important consideration in designing satellite/ground station communications systems. Satellite Interference Analysis and Simulation Using Personal Computers, AKSATINT, models the interference experienced by a generic satellite communications receiving station due to an interfering satellite. Both the desired and the interfering satellites are considered to be in elliptical orbits. The simulation contains computation of orbital positions of both satellites using classical orbital elements, calculation of the satellite antennae look angles for both satellites and elevation angles at the desired-satellite ground-station antenna, and computation of Doppler effect due to the motions of the satellites and the Earth's rotation. AKSATINT also computes the interference-tosignal-power ratio, taking into account losses suffered by the links. After computing the interference-to-signal-power ratio, the program computes the statistical quantities. The statistical formulation of the interference effect is presented in the form of a histogram of the interference to the desired signal power ratio. The program includes a flowchart, a sample run, and results of that run. AKSATINT is expected to be of general use to system designers and frequency managers in selecting the proper frequency under an interference scenario. The AKSATINT program is written in BASIC. It was designed to operate on the IBM Personal Computer AT or compatibles, and has been implemented under MS DOS 3.2. AKSATINT was developed in 1987.

  18. Interference Effects in Strong-Field Dissociative Ionization

    DEFF Research Database (Denmark)

    Yue, Lun; Madsen, Lars Bojer

    2015-01-01

    with simple energy conservation arguments. We explain the structures as interferences between wave packets released during different optical cycles, and during the same optical cycle, respectively. Both inter- and intracycle interference structures are clearly visible in the joint energy spectra. The shapes...

  19. Interference patterns and extinction ratio of the diatom Coscinodiscus granii

    DEFF Research Database (Denmark)

    Maibohm, Christian; Friis, Søren Michael Mørk; Ellegaard, M.;

    2015-01-01

    We report experimental and theoretical verification of the nature and position of multiple interference points of visible light transmitted through the valve of the centric diatom species Coscinodiscus granii. Furthermore, by coupling the transmitted light into an optical fiber and moving...... the diatom valve between constructive and destructive interference points, an extinction ratio of 20 dB is shown...

  20. 47 CFR 15.711 - Interference avoidance mechanisms.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Interference avoidance mechanisms. 15.711 Section 15.711 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL RADIO FREQUENCY DEVICES Television Band Devices § 15.711 Interference avoidance mechanisms. (a) Except as provided in §...

  1. Quantum coherence generated by interference-induced state selectiveness

    OpenAIRE

    Garreau, Jean Claude

    2001-01-01

    The relations between quantum coherence and quantum interference are discussed. A general method for generation of quantum coherence through interference-induced state selection is introduced and then applied to `simple' atomic systems under two-photon transitions, with applications in quantum optics and laser cooling.

  2. Fraunhofer regime of operation for superconducting quantum interference filters

    DEFF Research Database (Denmark)

    Shadrin, A.V.; Constantinian, K.Y.; Ovsyannikov, G.A.;

    2008-01-01

    Series arrays of superconducting quantum interference devices (SQUIDs) with incommensurate loop areas, so-called superconducting quantum interference filters (SQIFs), are investigated in the kilohertz and the gigahertz frequency range. In SQIFs made of high-T-c bicrystal junctions the flux...

  3. 47 CFR 80.92 - Prevention of interference.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Prevention of interference. 80.92 Section 80.92... MARITIME SERVICES Operating Requirements and Procedures Operating Procedures-General § 80.92 Prevention of...-communication causes interference to a communication which is already in progress, the interfering station...

  4. Ensuring Secure Non-interference of Programs by Game Semantics

    DEFF Research Database (Denmark)

    Dimovski, Aleksandar

    Non-interference is a security property which states that improper information leakages due to direct and indirect flows have not occurred through executing programs. In this paper we investigate a game semantics based formulation of non-interference that allows to perform a security analysis...

  5. Resistance to Cognitive Interference as a Function of MMPI Profile

    Science.gov (United States)

    Golden, Charles J.; Golden, Ellen E.

    1975-01-01

    This study tests the hypothesis that resistance to interference as measured by Stroop Color and Word Test is related to psychopathology. College student subjects were classified into three groups on the basis of their Minnesota Multiphasic Personality Inventory (MMPI) profile high points. Subjects' cognitive interference scores significantly…

  6. Role interference and subjective well-being among expatriate families

    NARCIS (Netherlands)

    Van der Zee, KI; Salome, E

    2005-01-01

    The present study examined the relation of demands and social support, and positive and negative Work-Home (WHI) and Home-Work interference (HWI) with the subjective well-being of expatriates. Moreover, we were also interested in crossover effects of expatriate interference to the subjective wellbei

  7. 47 CFR 15.17 - Susceptibility to interference.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Susceptibility to interference. 15.17 Section... § 15.17 Susceptibility to interference. (a) Parties responsible for equipment compliance are advised to..., amateur, land mobile, and non-geostationary mobile satellite feeder link earth stations, and of...

  8. Statistical modeling and analysis of interference in wireless networks

    NARCIS (Netherlands)

    Wildemeersch, Matthias

    2013-01-01

    In current wireless networks, interference is the main performance-limiting factor. The quality of a wireless link depends on the signal and interference power, which is strongly related to the spatial distribution of the concurrently transmitting network nodes, shortly denominated as the network ge

  9. The Development of Stimulus and Response Interference Control in Midchildhood

    Science.gov (United States)

    Cragg, Lucy

    2016-01-01

    Interference control, the ability to overcome distraction from irrelevant information, undergoes considerable improvement during childhood, yet the mechanisms driving these changes remain unclear. The present study investigated the relative influence of interference at the level of the stimulus or the response. Seven-, 10-, and 20-year-olds…

  10. Interference Alignment and Fairness Algorithms for MIMO Cognitive Radio Systems

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2015-01-01

    Full Text Available Interference alignment (IA is an effective technique to eliminate the interference among wireless nodes. In a multiinput multi-output (MIMO cognitive radio system, multiple secondary users can coexist with the primary user without generating any interference by using the IA technology. However, few works have considered the fairness of secondary users. In this paper, not only is the interference eliminated by IA, but also the fairness of secondary users is considered by two kinds of algorithms. Without losing generality, one primary user and K secondary users are considered in the network. Assuming perfect channel knowledge at the primary user, the interference from secondary users to the primary user is aligned into the unused spatial dimension which is obtained by water-filling among primary user. Also, the interference between secondary users can be eliminated by a modified maximum signal-to-interference-plus-noise algorithm using channel reciprocity. In addition, two kinds of fairness algorithms, max-min fairness and proportional fairness, among secondary users are proposed. Simulation results show the effectiveness of the proposed algorithms in terms of suppressed interference and fairness of secondary nodes. What is more, the performances of the two fairness algorithms are compared.

  11. Base band data for testing interference mitigation algorithms

    NARCIS (Netherlands)

    Bell, JF; Hall, PJ; Wilson, WE; Sault, RJ; Smegal, RJ; Smith, MR; van Straten, W; Kesteven, MJ; Ferris, RH; Briggs, FH; Carrad, GJ; Sinclair, MW; Gough, RG; Sarkissian, JM; Bunton, JD; Bailes, M

    2001-01-01

    Digital signal processing is one of many valuable tools for suppressing unwanted signals or interference. Building hardware processing engines seems to be the way to best implement some classes of interference suppression but is, unfortunately, expensive and time-consuming, especially if several mit

  12. Fiber Optic Pressure Sensor using Multimode Interference

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz-Perez, V I; Sanchez-Mondragon, J J [INAOE, Apartado Postal 51 y 216, Puebla 72000 (Mexico); Basurto-Pensado, M A [CIICAp, Universidad Autonoma del Estado de Morelos (Mexico); LiKamWa, P [CREOL, University of Central Florida, Orlando, FL 32816 (United States); May-Arrioja, D A, E-mail: iruiz@inaoep.mx, E-mail: mbasurto@uaem.mx, E-mail: delta_dirac@hotmail.com, E-mail: daniel_may_arrioja@hotmail.com [UAT Reynosa Rodhe, Universidad Autonoma de Tamaulipas (Mexico)

    2011-01-01

    Based on the theory of multimode interference (MMI) and self-image formation, we developed a novel intrinsic optical fiber pressure sensor. The sensing element consists of a section of multimode fiber (MMF) without cladding spliced between two single mode fibers (SMF). The MMI pressure sensor is based on the intensity changes that occur in the transmitted light when the effective refractive index of the MMF is changed. Basically, a thick layer of Polydimethylsiloxane (PDMS) is placed in direct contact with the MMF section, such that the contact area between the PDMS and the fiber will change proportionally with the applied pressure, which results in a variation of the transmitted light intensity. Using this configuration, a good correlation between the measured intensity variations and the applied pressure is obtained. The sensitivity of the sensor is 3 {mu}V/psi, for a range of 0-60 psi, and the maximum resolution of our system is 0.25 psi. Good repeatability is also observed with a standard deviation of 0.0019. The key feature of the proposed pressure sensor is its low fabrication cost, since the cost of the MMF is minimal.

  13. Interference with the patient-physician relationship

    Directory of Open Access Journals (Sweden)

    Robbins RA

    2012-11-01

    Full Text Available No abstract available. Article truncated at 150 words. “Life is like a boomerang. Our thoughts, deeds and words return to us sooner or later, with astounding accuracy.”-Brant M. Bright, former project leader with IBM A recent sounding board in the New England Journal of Medicine discussed legislative interference with the patient-physician relationship (1. The authors, the executive staff leadership of the American Academy of Family Physicians, the American Academy of Pediatrics, the American College of Obstetricians and Gynecologists, the American College of Physicians, and the American College of Surgeons believe that legislators should abide by principles that put patients’ best interests first. Critical to achieving this goal is respect for the importance of scientific evidence, patient autonomy, and the patient-physician relationship. According to the authors, lawmakers are increasingly intruding into the realm of medical practice, often to satisfy political agendas without regard to established, evidence-based guidelines for care. The article goes on to cite examples including: The Florida ….

  14. RNA interference and Register Machines (extended abstract

    Directory of Open Access Journals (Sweden)

    Masahiro Hamano

    2012-11-01

    Full Text Available RNA interference (RNAi is a mechanism whereby small RNAs (siRNAs directly control gene expression without assistance from proteins. This mechanism consists of interactions between RNAs and small RNAs both of which may be single or double stranded. The target of the mechanism is mRNA to be degraded or aberrated, while the initiator is double stranded RNA (dsRNA to be cleaved into siRNAs. Observing the digital nature of RNAi, we represent RNAi as a Minsky register machine such that (i The two registers hold single and double stranded RNAs respectively, and (ii Machine's instructions are interpreted by interactions of enzyme (Dicer, siRNA (with RISC com- plex and polymerization (RdRp to the appropriate registers. Interpreting RNAi as a computational structure, we can investigate the computational meaning of RNAi, especially its complexity. Initially, the machine is configured as a Chemical Ground Form (CGF, which generates incorrect jumps. To remedy this problem, the system is remodeled as recursive RNAi, in which siRNA targets not only mRNA but also the machine instructional analogues of Dicer and RISC. Finally, probabilistic termination is investigated in the recursive RNAi system.

  15. Detection of radio frequency interference over ocean

    Science.gov (United States)

    Tian, Xiaoxu

    The geostationary satellite television (TV) signals that are reflected off the ocean surfaces could enter the AMSR-E antenna, resulting in RFI (Radio Frequency Interference) contamination in AMSR-E 10.65 and 18.7 GHz channels. If not detected, the presence of RFI signals can result in false retrievals of oceanic environmental parameters (e.g., sea surface temperature, sea surface wind speed, rain water path) from microwave imaging radiance measurements. This study first examined the geometric relationship between the RFI source, geostationary TV satellite, and AMSR-E observation. Then a normalized Principal Component Analysis (NPCA) method is proposed and applied for RFI detection over oceans in Advanced Microwave Scanning Radiometer (AMSR)-E observations. It is found that the RFI-contaminated observations on AMSR-E descending node at 10.65 and 18.7 GHz can be successively detected near coastal areas surrounding Europe and United States continents. The results yielded from the geometric examination at another angle verify those signals detected with NPCA. The proposed NPCA algorithm is applicable in an operational environment for fast data processing and data dissemination, and is different from earlier methods, which often require a priori information.

  16. Review Results on Wing-Body Interference

    Directory of Open Access Journals (Sweden)

    Frolov Vladimir

    2016-01-01

    Full Text Available The paper presents an overview of results for wing-body interference, obtained by the author for varied wing-body combinations. The lift-curve slopes of the wing-body combinations are considered. In this paper a discrete vortices method (DVM and 2D potential model for cross-flow around fuselage are used. The circular and elliptical cross-sections of the fuselage and flat wings of various forms are considered. Calculations showed that the value of the lift-curve slopes of the wing-body combinations may exceed the same value for an isolated wing. This result confirms an experimental data obtained by other authors earlier. Within a framework of the used mathematical models the investigations to optimize the wing-body combination were carried. The present results of the optimization problem for the wing-body combination allowed to select the optimal geometric characteristics for configuration to maximize the values of the lift-curve slopes of the wing-body combination. It was revealed that maximums of the lift-curve slopes for the optimal mid-wing configuration with elliptical cross-section body had a sufficiently large relative width of the body (more than 30% of the span wing.

  17. Environmental Factors that Interfere in the Germination

    Directory of Open Access Journals (Sweden)

    Lisiane de Souza

    2014-12-01

    Full Text Available This paper refers to the application of experiments with sixth graders of elementary school, aiming motivation, skills development focused on observation, interpersonal relationships in teams, related to the various forms of language skills, as well to identify and resume misconceptions about the external (environmental factors required for seed germination, in order that the contents developed this year refer to the study of the earth, soil, water and air, among others, and that many students do not understand all the concepts and the importance of these factors for the existence of living beings. The experiments were organized in two stages, first to observe the influence of soil and another moment to observe the interference of water, air and light. The temperature impractical activities were conducted, however, during the observation period (three weeks experiments remained in a controlled environment in the science laboratory. For the experiments we used materials easily found in commerce, some recycled; students were organized into six teams, which improved the data collection, the maintenance of the experiments, the calculations of the percentages, and the producing of report. Many of these contents had not yet been studied in other disciplines, but were developed in the discipline of science, respecting prior knowledge and cognitive abilities. The use of experiments was effective for the construction of new knowledge and to develop skills necessary to start the search.

  18. Separating cyclostationary signals from spectrally overlapping interference

    Institute of Scientific and Technical Information of China (English)

    GUO Jie; LIU Yun; YE Zhi-hui; SONG Tie-cheng; SHEN Lian-feng

    2006-01-01

    This paper studies an algorithm about separating spectmlly overlapping signals using the cyclostationary properties of signals.On the basis of direct sequence spread system (DSSS),frequency shift filter is added into the receiver of the communication system.Although the structure of frequency shift filter is more complicated than the time-domain filter,it uses both time correlations and frequency spectrum correlations so it can achieve better performances on separating the overlapping signals.After the analysis of cyclostationary characteristic and frequency spectrum correlation,the structure of the frequency shift filter can be gained.Then,a self-adaptive algorithm is utilized for the purpose of achieving optimum multidimensional tap weights of frequency shift components.The simulation results indicate that this method can efficiently separate overlapping signals,and its error rate is lower than the time-domain filter or DSSS system by two orders of magnitude on the condition that high-power interference is added into the system.

  19. How Facilitation May Interfere with Ecological Speciation

    Directory of Open Access Journals (Sweden)

    P. Liancourt

    2012-01-01

    Full Text Available Compared to the vast literature linking competitive interactions and speciation, attempts to understand the role of facilitation for evolutionary diversification remain scarce. Yet, community ecologists now recognize the importance of positive interactions within plant communities. Here, we examine how facilitation may interfere with the mechanisms of ecological speciation. We argue that facilitation is likely to (1 maintain gene flow among incipient species by enabling cooccurrence of adapted and maladapted forms in marginal habitats and (2 increase fitness of introgressed forms and limit reinforcement in secondary contact zones. Alternatively, we present how facilitation may favour colonization of marginal habitats and thus enhance local adaptation and ecological speciation. Therefore, facilitation may impede or pave the way for ecological speciation. Using a simple spatially and genetically explicit modelling framework, we illustrate and propose some first testable ideas about how, when, and where facilitation may act as a cohesive force for ecological speciation. These hypotheses and the modelling framework proposed should stimulate further empirical and theoretical research examining the role of both competitive and positive interactions in the formation of incipient species.

  20. High-Q Bandpass Comb Filter for Mains Interference Extraction

    Directory of Open Access Journals (Sweden)

    Neycheva T.

    2009-12-01

    Full Text Available This paper presents a simple digital high-Q bandpass comb filter for power-line (PL or other periodical interference extraction. The filter concept relies on a correlated signal average resulting in alternating constructive and destructive spectrum interference i.e. the so-called comb frequency response. The presented filter is evaluated by Matlab simulations with real ECG signal contaminated with low amplitude PL interference. The made simulations show that this filter accurately extract the PL interference. It has high-Q notches only at PL odd harmonics and is appropriate for extraction of any kind of odd harmonic interference including rectangular shape. The filter is suitable for real-time operation with popular low-cost microcontrollers.

  1. Ruling Out Multi-Order Interference in Quantum Mechanics

    CERN Document Server

    Sinha, Urbasi; Jennewein, Thomas; Laflamme, Raymond; Weihs, Gregor

    2010-01-01

    Quantum mechanics and gravitation are two pillars of modern physics. Despite their success in describing the physical world around us, they seem to be incompatible theories. There are suggestions that one of these theories must be generalized to achieve unification. For example, Born's rule, one of the axioms of quantum mechanics could be violated. Born's rule predicts that quantum interference, as shown by a double slit diffraction experiment, occurs from pairs of paths. A generalized version of quantum mechanics might allow multi-path, i.e. higher order interferences thus leading to a deviation from the theory. We performed a three slit experiment with photons and bounded the magnitude of three path interference to less than 10-2 of the expected two-path interference, thus ruling out third and higher order interference and providing a bound on the accuracy of Born's rule. Our experiment is consistent with the postulate both in semi-classical and quantum regimes.

  2. Modular interference characteristic of two-mode fiber

    Institute of Scientific and Technical Information of China (English)

    Helin Wang; Weihong Bi; Aijun Yang; Feng Liu

    2006-01-01

    The modular interference characteristics of circular-core and elliptical-core two-mode fibers are investigated in theory. The intensity distribution and figure of two-lobe mode patterns are evaluated and simulated quantitatively for different phase difference change between LP01 and LPeven11 mode. The interference mode patters of elliptical-core and circular-core two-mode fibers are compared, the result shows that the two-lobe interference patters of the two-mode fibers generate energy exchange and oscillation, and thedifference is that the interference mode patterns of circular-core two-mode fiber are almost elliptical, while the interference mode pattern of elliptical-core two-mode fiber is approximately circular on condition that proper selection of the ellipticity. Their two-dimensional (2D) profile determines the choice of the core shape of the information pick-up fiber.

  3. Adaptive control of interference at satellite earth stations

    Science.gov (United States)

    Carlin, J. W.; Chipaloski, A. C.; Steinberger, M. L.

    This paper presents system designs for adaptive interference cancellation at satellite earth stations. Cancellation systems to reduce co-frequency, foreign system (interference from terrestrial microwave radio systems) and adjacent satellite interference as well as interference from co-frequency, orthogonally polarized channels are considered. The systems employ common building blocks: rf weight circuits, an analog processor consisting of a multiplier and integrator, and a dither generator which provides multiple orthogonal sequences so that the rf weights in the cancellation network can be varied and optimized simultaneously. Measured data from field installations equipped with cross-pol. adjacent satellite and sidelobe cancellation systems is presented and discussed. The measured sidelobe canceler performance is compared with performance bounds calculated to result from tolerable circuit mismatches, thermal noise and 'power inversion' effects. The effect of multipath coupled interference is discussed and shown to be a significant factor which limits sidelobe canceler performance.

  4. Nonlinear interference and unidirectional wave mixing in metamaterials.

    Science.gov (United States)

    Rose, Alec; Huang, Da; Smith, David R

    2013-02-01

    When both electric and magnetic mechanisms contribute to a particular nonlinear optical process, there exists the possibility for nonlinear interference, often characterized by constructive or destructive interference in the radiation pattern of harmonics and mix waves. However, observation of a significant effect from nonlinear interference requires careful balancing of the various contributions. For this purpose, we propose an artificial metamaterial, using the formalism of nonlinear magnetoelectric coupling to simultaneously engineer the nonlinear polarization and magnetization. We confirm our predictions of nonlinear interference with both simulations and experiment, demonstrating unidirectional wave mixing in two microwave metamaterials. Our results point toward an ever wider range of nonlinear properties, in which nonlinear interference is just one of many potential applications.

  5. Nonmonotonic quantum-to-classical transition in multiparticle interference

    DEFF Research Database (Denmark)

    Ra, Young-Sik; Tichy, Malte; Lim, Hyang-Tag;

    2013-01-01

    Quantum-mechanical wave–particle duality implies that probability distributions for granular detection events exhibit wave-like interference. On the single-particle level, this leads to self-interference—e.g., on transit across a double slit—for photons as well as for large, massive particles...... that interference fades away monotonically with increasing distinguishability—in accord with available experimental evidence on the single- and on the many-particle level. Here, we demonstrate experimentally and theoretically that such monotonicity of the quantum-to-classical transition is the exception rather than...... the rule whenever more than two particles interfere. As the distinguishability of the particles is continuously increased, different numbers of particles effectively interfere, which leads to interference signals that are, in general, nonmonotonic functions of the distinguishability of the particles...

  6. Electromagnetic interference in electrical systems of motor vehicles

    Science.gov (United States)

    Dziubiński, M.; Drozd, A.; Adamiec, M.; Siemionek, E.

    2016-09-01

    Electronic ignition system affects the electronic equipment of the vehicle by electric and magnetic fields. The measurement of radio electromagnetic interference originating from the ignition system affecting the audiovisual test bench was carried out with a variable speed of the ignition system. The paper presents measurements of radio electromagnetic interference in automobiles. In order to determine the level of electromagnetic interference, the audiovisual test bench was equipped with a set of meters for power consumption and assessment of the level of electromagnetic interference. Measurements of the electromagnetic interference level within the audiovisual system were performed on an experimental test bench consisting of the ignition system, starting system and charging system with an alternator and regulator.

  7. Pluto's atmosphere near perihelion

    International Nuclear Information System (INIS)

    A recent stellar occultation has confirmed predictions that Pluto has an atmosphere which is sufficiently thick to uniformly envelope the planet and to extend far above the surface. Pluto's atmosphere consists of methane and perhaps other volatile gases at temperatures below their freezing points; it should regulate the surface temperature of its volatile ices to a globally uniform value. As Pluto approaches and passes through perihelion, a seasonal maximum in the atmospheric bulk and a corresponding minimum in the exposed volatile ice abundance is expected to occur. The lag in maximum atmospheric bulk relative to perihelion will be diagnostic of the surface thermal properties. An estimate of Pluto's atmospheric bulk may result if a global darkening (resulting from the disappearance of the seasonally deposited frosts) occurs before the time of maximum atmospheric bulk. The ice deposited shortly after perihelion may be diagnostic of the composition of Pluto's volatile reservoir

  8. Measurement of the Atmospheric $\

    CERN Document Server

    Aartsen, M G; Abdou, Y; Ackermann, M; Adams, J; Aguilar, J A; Ahlers, M; Altmann, D; Andeen, K; Auffenberg, J; Bai, X; Baker, M; Barwick, S W; Baum, V; Bay, R; Beattie, K; Beatty, J J; Bechet, S; Tjus, J Becker; Becker, K -H; Bell, M; Benabderrahmane, M L; BenZvi, S; Berdermann, J; Berghaus, P; Berley, D; Bernardini, E; Bertrand, D; Besson, D Z; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohaichuk, S; Bohm, C; Bose1, D; Boser, S; Botner, O; Brayeur, L; Brown, A M; Bruijn, R; Brunner, J; Buitink, S; Carson, M; Casey, J; Casier, M; Chirkin, D; Christy, B; Clark, K; Clevermann, F; Cohen, S; Cowen, D F; Silva, A H Cruz; Danninger, M; Daughhetee, J; Davis, J C; De Clercq, C; De Ridder, S; Descamps, F; Desiati, P; de Vries-Uiterweerd, G; DeYoung, T; Diaz-Velez, J C; Dreyer, J; Dumm, J P; Dunkman, M; Eagan, R; Eberhardt, B; Eisch, J; Ellsworth, R W; Engdegard, O; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Feusels, T; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Franckowiak, A; Franke, R; Frantzen, K; Fuchs, T; Gaisser, T K; Gallagher, J; Gerhardt, L; Gladstone, L; Glusenkamp, T; Goldschmidt, A; Golup, G; Goodman, J A; Gora, D; Grant, D; Gross, A; Grullon, S; Gurtner, M; Ha, C; Ismail, A Haj; Hallgren, A; Halzen, F; Hanson, K; Heereman, D; Heimann, P; Heinen, D; Helbing, K; Hellauer, R; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huelsnitz, W; Hulth, P O; Hultqvist, K; Hussain, S; Ishihara, A; Jacobi, E; Jacobsen, J; Japaridze, G S; Jlelati, O; Kappes, A; Karg, T; Karle, A; Kiryluk, J; Kislat, F; Klas, J; Klein, S R; Kohne, J -H; Kohnen, G; Kolanoski, H; Kopke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Krasberg, M; Kroll, G; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Landsman, H; Larson, M J; Lauer, R; Lesiak-Bzdak, M; Lunemann, J; Madsen, J; Maruyama, R; Mase, K; Matis, H S; McNally, F; Meagher, K; Merck, M; Meszaros, P; Meures, T; Miarecki, S; Middell, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Olivo, M; O'Murchadha, A; Panknin, S; Paul, L; Pepper, J A; Heros, C Perez de los; Pieloth, D; Pirk, N; Posselt, J; Price, P B; Przybylski, G T; Radel, L; Rawlins, K; Redl, P; Resconi, E; Rhode, W; Ribordy, M; Richman, M; Riedel, B; Rodrigues, J P; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Salameh, T; Sander, H -G; Santander, M; Sarkar, S; Schatto, K; Scheel, M; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schoneberg, S; Schonherr, L; Schonwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Seo, S H; Sestayo, Y; Seunarine, S; Sheremata, C; Smith, M W E; Soiron, M; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stasik, A; Stezelberger, T; Stokstad, R G; Stoss, A; Strahler, E A; Strom, R; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Ter-Antonyan, S; Tilav, S; Toale, P A; Toscano, S; Usner, M; van der Drift, D; van Eijndhoven, N; Van Overloop, A; van Santen, J; Vehring, M; Voge1, M; Vraeghe, M; Walck, C; Waldenmaier, T; Wallraff, M; Walter, M; Wasserman, R; Weaver, Ch; Wendt, C; Westerhoff, S; Whitehorn, N; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, C; Xu, D L; Xu, X W; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zierke, S; Zilles, A; Zoll, M

    2012-01-01

    We report the first observation in a high energy neutrino telescope of cascades induced by atmospheric electron neutrinos and by neutral current interactions of atmospheric neutrinos of all flavors. Using data recorded during the first year of operation of IceCube's DeepCore low energy extension, a sample of 1029 events is observed in 281 days of data. The number of observed cascades is $N_{\\rm cascade} = 496 \\pm 66 (stat.) \\pm 88(syst.)$ and the rest of the sample consists of residual backgrounds due to atmospheric muons and charged current interactions of atmospheric muon neutrinos. The flux of the atmospheric electron neutrinos is determined in the energy range between approximately 80 GeV and 6 TeV and is consistent with models of atmospheric neutrinos.

  9. Atmospheric Circulation of Exoplanets

    CERN Document Server

    Showman, Adam P; Menou, Kristen

    2009-01-01

    We survey the basic principles of atmospheric dynamics relevant to explaining existing and future observations of exoplanets, both gas giant and terrestrial. Given the paucity of data on exoplanet atmospheres, our approach is to emphasize fundamental principles and insights gained from Solar-System studies that are likely to be generalizable to exoplanets. We begin by presenting the hierarchy of basic equations used in atmospheric dynamics, including the Navier-Stokes, primitive, shallow-water, and two-dimensional nondivergent models. We then survey key concepts in atmospheric dynamics, including the importance of planetary rotation, the concept of balance, and scaling arguments to show how turbulent interactions generally produce large-scale east-west banding on rotating planets. We next turn to issues specific to giant planets, including their expected interior and atmospheric thermal structures, the implications for their wind patterns, and mechanisms to pump their east-west jets. Hot Jupiter atmospheric d...

  10. Ambroxol interferes with Pseudomonas aeruginosa quorum sensing.

    Science.gov (United States)

    Lu, Qi; Yu, Jialin; Yang, Xiqiang; Wang, Jiarong; Wang, Lijia; Lin, Yayin; Lin, Lihua

    2010-09-01

    The mucolytic agent ambroxol has been reported to interfere with the formation of Pseudomonas aeruginosa-derived biofilms in addition to reducing alginate production by undefined mechanisms. Since quorum sensing is a key regulator of virulence and biofilm formation, we examined the effects of ambroxol on P. aeruginosa PAO1 wild-type bacterial clearance rates, adhesion profiles and biofilm formation compared with the quorum sensing-deficient, double-mutant strains DeltalasR DeltarhlR and DeltalasI DeltarhlI. Data presented in this report demonstrated that ambroxol treatment reduced survival rates of the double-mutant strains compared with the wild-type strain in a dose-dependent manner even though the double-mutants had increased adhesion in the presence of ambroxol compared with the wild-type strain. The PAO1 wild-type strain produced a significantly thicker biofilm (21.64+/-0.57 microm) compared with the biofilms produced by the DeltalasR DeltarhlR (7.36+/-0.2 microm) and DeltalasI DeltarhlI (6.62+/-0.31 microm) isolates. Ambroxol treatment reduced biofilm thickness, increased areal porosity, and decreased the average diffusion distance and textual entropy of wild-type and double-mutant strains. However, compared with the double-mutant strains, the changes observed for the wild-type strain were more clearly defined. Finally, ambroxol exhibited significant antagonistic quorum-sensing properties, suggesting that it could be adapted for use clinically in the treatment of cystic fibrosis and to reduce biofilm formation and in the colonisation of indwelling devices.

  11. Ambroxol interferes with Pseudomonas aeruginosa quorum sensing.

    Science.gov (United States)

    Lu, Qi; Yu, Jialin; Yang, Xiqiang; Wang, Jiarong; Wang, Lijia; Lin, Yayin; Lin, Lihua

    2010-09-01

    The mucolytic agent ambroxol has been reported to interfere with the formation of Pseudomonas aeruginosa-derived biofilms in addition to reducing alginate production by undefined mechanisms. Since quorum sensing is a key regulator of virulence and biofilm formation, we examined the effects of ambroxol on P. aeruginosa PAO1 wild-type bacterial clearance rates, adhesion profiles and biofilm formation compared with the quorum sensing-deficient, double-mutant strains DeltalasR DeltarhlR and DeltalasI DeltarhlI. Data presented in this report demonstrated that ambroxol treatment reduced survival rates of the double-mutant strains compared with the wild-type strain in a dose-dependent manner even though the double-mutants had increased adhesion in the presence of ambroxol compared with the wild-type strain. The PAO1 wild-type strain produced a significantly thicker biofilm (21.64+/-0.57 microm) compared with the biofilms produced by the DeltalasR DeltarhlR (7.36+/-0.2 microm) and DeltalasI DeltarhlI (6.62+/-0.31 microm) isolates. Ambroxol treatment reduced biofilm thickness, increased areal porosity, and decreased the average diffusion distance and textual entropy of wild-type and double-mutant strains. However, compared with the double-mutant strains, the changes observed for the wild-type strain were more clearly defined. Finally, ambroxol exhibited significant antagonistic quorum-sensing properties, suggesting that it could be adapted for use clinically in the treatment of cystic fibrosis and to reduce biofilm formation and in the colonisation of indwelling devices. PMID:20580207

  12. Inhibition of Henipavirus infection by RNA interference.

    Science.gov (United States)

    Mungall, Bruce A; Schopman, Nick C T; Lambeth, Luke S; Doran, Tim J

    2008-12-01

    Nipah virus (NiV) and Hendra virus (HeV) are recently emerged zoonotic paramyxoviruses exclusively grouped within a new genus, Henipavirus. These viruses cause fatal disease in a wide range of species, including humans. Both NiV and HeV have continued to re-emerge sporadically in Bangladesh and Australia, respectively. There are currently no therapeutics or vaccines available to treat Henipavirus infection and both are classified as BSL4 pathogens. RNA interference (RNAi) is a process by which double-stranded RNA directs sequence-specific degradation of messenger RNA in animal and plant cells. Small interfering RNAs (siRNAs) mediate RNAi by inhibiting gene expression of homologous mRNA and our preliminary studies suggest RNAi may be a useful approach to developing novel therapies for these highly lethal pathogens. Eight NiV siRNA molecules (four L and four N gene specific), two HeV N gene specific, and two non-specific control siRNA molecules were designed and tested for their ability to inhibit a henipavirus minigenome replication system (which does not require the use of live virus) in addition to live virus infections in vitro. In the minigenome assay three out of the four siRNAs that targeted the L gene of NiV effectively inhibited replication. In contrast, only NiV N gene siRNAs were effective in reducing live NiV replication, suggesting inhibition of early, abundantly expressed gene transcripts may be more effective than later, less abundant transcripts. Additionally, some of the siRNAs effective against NiV infection were only partially effective inhibitors of HeV infection. An inverse correlation between the number of nucleotide mismatches and the efficacy of siRNA inhibition was observed. The demonstration that RNAi effectively inhibits henipavirus replication in vitro, is a novel approach and may provide an effective therapy for these highly lethal, zoonotic pathogens. PMID:18687361

  13. Interference between nanoparticles and metal homeostasis

    Energy Technology Data Exchange (ETDEWEB)

    Petit, A N; Catty, P; Charbonnier, P; Cuillel, M; Mintz, E; Moulis, J M; Niviere, V; Choudens, S Ollagnier de [Laboratoire de Chimie et Biologie des Metaux UMR 5249 CEA-CNRS-UJF, 17 rue des Martyrs, 38054 Grenoble Cedex 09 (France); Garcia, C Aude; Candeias, S; Chevallet, M; Collin-Faure, V; Lelong, C; Luche, S; Rabilloud, T [Laboratoire de Biochimie et Biophysique des Systemes Integres UMR 5092 CNRS-CEA-UJF, 17 rue des martyrs, 38054 Grenoble Cedex 09 (France); Casanova, A; Herlin-Boime, N [Laboratoire Edifices Nanometriques URA 2453 CEA-CNRS-IRAMIS, 91191 Gif-sur-Yvette (France); Douki, T; Ravanat, J L; Sauvaigo, S, E-mail: isabelle.michaud-soret@cea.fr [Laboratoire Lesions des Acides Nucleiques UMR E3 CEA-UJF, 17 rue des Martyrs, 38054 Grenoble Cedex 09 (France)

    2011-07-06

    The TiO{sub 2} nanoparticles (NPs) are now produced abundantly and widely used in a variety of consumer products. Due to the important increase in the production of TiO{sub 2}-NPs, potential widespread exposure of humans and environment may occur during both the manufacturing process and final use. Therefore, the potential toxicity of TiO{sub 2}-NPs on human health and environment has attracted particular attention. Unfortunately, the results of the large number of studies on the toxicity of TiO{sub 2}-NPs differ significantly, mainly due to an incomplete characterization of the used nanomaterials in terms of size, shape and crystalline structure and to their unknown state of agglomeration/aggregation. The purpose of our project entitled NanoBioMet is to investigate if interferences between nanoparticles and metal homeostasis could be observed and to study the toxicity mechanisms of TiO{sub 2}-NPs with well-characterized physicochemical parameters, using proteomic and molecular approaches. A perturbation of metal homeostasis will be evaluated upon TiO{sub 2}-NPs exposure which could generate reactive oxygen species (ROS) production. Moreover, oxidative stress consequences such as DNA damage and lipid peroxidation will be studied. The toxicity of TiO{sub 2}-NPs of different sizes and crystalline structures will be evaluated both in prokaryotic (E. coli) and eukaryotic cells (A549 human pneumocytes, macrophages, and hepatocytes). First results of the project will be presented concerning the dispersion of TiO{sub 2}-NPs in bacterial medium, proteomic studies on total extracts of macrophages and genotoxicity on pneumocytes.

  14. Role of RNA interference in plant improvement

    Science.gov (United States)

    Jagtap, Umesh Balkrishna; Gurav, Ranjit Gajanan; Bapat, Vishwas Anant

    2011-06-01

    Research to alter crops for their better performance involving modern technology is underway in numerous plants, and achievements in transgenic plants are impacting crop improvements in unparalleled ways. Striking progress has been made using genetic engineering technology over the past two decades in manipulating genes from diverse and exotic sources, and inserting them into crop plants for inducing desirable characteristics. RNA interference (RNAi) has recently been identified as a natural mechanism for regulation of gene expression in all higher organisms from plants to humans and promises greater accuracy and precision to plant improvement. The expression of any gene can be down-regulated in a highly explicit manner exclusive of affecting the expression of any other gene by using RNAi technologies. Additional research in this field has been focused on a number of other areas including microRNAs, hairpin RNA, and promoter methylation. Manipulating new RNAi pathways, which generate small RNA molecules to amend gene expression in crops, can produce new quality traits and having better potentiality of protection against abiotic and biotic stresses. Nutritional improvement, change in morphology, or enhanced secondary metabolite synthesis are some of the other advantages of RNAi technology. In addition to its roles in regulating gene expression, RNAi is also used as a natural defense mechanism against molecular parasites such as jumping genes and viral genetic elements that affect genome stability. Even though much advancement has been made on the field of RNAi over the preceding few years, the full prospective of RNAi for crop improvement remains to be fully realized. The intricacy of RNAi pathway, the molecular machineries, and how it relates to plant development are still to be explained.

  15. PROBABILISTIC-STATISTICAL MODELING THE INTERFERENCES FROM ELECTRIC LOCOMOTIVES

    Directory of Open Access Journals (Sweden)

    Orlov A. I.

    2015-02-01

    Full Text Available The movements of electric locomotives create the interferences affecting the wired link. The creation of sufficiently technical effective and at the same time cost-effective means of protection from wireline interferences generated traction networks assumes as a preparatory phase to develop mathematical models of interference caused by electric locomotives. We have developed a probabilistic-statistical model of interferences caused by electric locomotives. The asymptotic distribution of the total interference is the distribution of the length of the two-dimensional random vector whose coordinates - independent normally distributed random variables with mean 0 and variance 1. Limit theorem is proved for the expectation of the total amplitude of the interferences. Monte-Carlo method is used to study the rate of convergence of the expectation of the total amplitude of the interferences to the limiting value. We used an algorithm of mixing developed by MacLaren-Marsaglia (M-algorithm. Five sets of amplitudes are analyzed, selected in accordance with the recommendations of experts in the field of traction AC networks. The most rapid convergence to the limit takes place in the case of equal amplitudes. It was found that the maximum possible average value of the amplitude of the random noise by 7.4% less than the previously used value, which promises a significant economic impact

  16. Adaptive single-antenna transmit selection with interference suppression

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2011-10-01

    This paper studies the performance of adaptive transmit selection with co-channel interference suppression in multipath fading channels. The adaptive selection algorithms are configured for single-antenna bandwidth-efficient or power-efficient transmission with as low transmit channel estimations as possible. Due to the fact that the number of active co-channel interfering signals and their corresponding powers experience random behavior, the adaptation to channels conditions, assuming uniform buffer and traffic loading, is proposed to be jointly based on the transmit channels instantaneous signal-to-noise ratios (SNRs) and signal-to-interference-plus-noise ratios (SINRs). Two interference cancelation algorithms are considered. The first algorithm assumes that the receiver eliminates the impact of the strongest subset of interferers, whereas the second algorithm suggests random cancelation of interferers to further reduce processing complexity. The impact of outdated ordering of interferers powers on the efficiency of interference cancelation, and the effect of imperfect prediction of transmit channels for desired user adaptation are investigated. Analytical formulations for various performance measures and comparisons between the performance and processing complexity of different adaptation schemes are presented. © 2011 IEEE.

  17. RF interference at ground stations located in populated areas

    Science.gov (United States)

    Adams, N.; Bitman, J.; Copeland, D.; Srinivasan, D.; Garcia, A.

    Ground stations located in populated areas must contend with RF interference (RFI). While RF interference may disrupt occasional satellite contacts, disruption statistics in many cases are manageable. Thus the RF environment must be statistically characterized in order to predict availability and detect changes in the environment. An RF monitoring and recording system is essential to both characterize the RF environment and send alarms when interference appears. This paper presents a study of RF interference at the Satellite Communications Facility (SCF) located at The Johns Hopkins University Applied Physics Laboratory, and describes the impact of RF interference on the NASA Van Allen Probes mission. The area surrounding the SCF, located in Laurel, Maryland, was rural farmland when the SCF was commissioned in 1963. Since then the area has experienced tremendous commercial and residential development. Concurrent with this development RF activity has increased. In particular, increased RF interference is evident within the Van Allen Probes' S-band downlink allocation. The interference is due to other licensed parties, out-of-band commercial emissions, as well as natural phenomena. Some RFI sources have been identified, whereas others remain unknown. In this paper we describe the RF environment, and present a statistical characterization that shows that RFI has only a small impact on ground station availability. We also discuss operational considerations, including hand-shaking protocols and coordination with spectrum management.

  18. Wide spread spectrum watermarking with side information and interference cancellation

    CERN Document Server

    Guelvouit, Gaëtan Le; 10.1117/12.476839

    2008-01-01

    Nowadays, a popular method used for additive watermarking is wide spread spectrum. It consists in adding a spread signal into the host document. This signal is obtained by the sum of a set of carrier vectors, which are modulated by the bits to be embedded. To extract these embedded bits, weighted correlations between the watermarked document and the carriers are computed. Unfortunately, even without any attack, the obtained set of bits can be corrupted due to the interference with the host signal (host interference) and also due to the interference with the others carriers (inter-symbols interference (ISI) due to the non-orthogonality of the carriers). Some recent watermarking algorithms deal with host interference using side informed methods, but inter-symbols interference problem is still open. In this paper, we deal with interference cancellation methods, and we propose to consider ISI as side information and to integrate it into the host signal. This leads to a great improvement of extraction performance ...

  19. The effects of menstrual-related pain on attentional interference.

    Science.gov (United States)

    Keogh, Edmund; Cavill, Rebecca; Moore, David J; Eccleston, Christopher

    2014-04-01

    Pain-related attentional interference has been found in both chronic pain and laboratory-inducted pain settings. However, few studies have examined such interference effects during common everyday painful episodes. Menstrual cycle-related pain is a common pain that affects a large number of women on a regular basis. The purpose of the current study was, therefore, to examine the effects of menstrual pain on attentional interference. Fifty-two healthy adult women were tested during 2 different phases of their menstrual cycles: once during a nonpain phase (mid follicular), and once while experiencing menstrual pain (late luteal/early follicular). On each testing session, participants received a battery of 4 attentional interference tasks that included selective attention (flanker task), attention span (n-back task), attentional switching (switching task), and divided attention (dual task). Greater attentional interference effects were found to occur during the menstrual pain phase compared to the nonpain phase. Interestingly, the nature of this effect was a general worsening in performance (e.g., slowing, less accurate), rather than a specific attentional deficit. These results add to a growing literature that generally indicates that attentional interference occurs across a range of different types of pain, including common painful episodes. However, they also highlight that the specific nature of this interference effect may depend on the type pain under consideration. Implications of these findings are also considered.

  20. Designing Dynamic Atmospheres

    DEFF Research Database (Denmark)

    Højlund, Marie; Kinch, Sofie

    2012-01-01

    This paper addresses the notion of atmospheres from a designerly perspective, and discusses temporal challenges facing interaction designers when acknowledging the dynamic character of it. As atmospheres are created in the relation between body, space, and time, a pragmatic approach seems useful...

  1. Proterozoic atmospheric oxygen

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene

    2014-01-01

    This article is concerned with the evolution of atmospheric oxygen concentrations through the Proterozoic Eon. In particular, this article will seek to place the history of atmospheric oxygenation through the Proterozoic Eon in the context of the evolving physical environment including the history...

  2. Update on Atmospheric Neutrinos

    CERN Document Server

    González-Garciá, M Concepción; Peres, O L G; Stanev, T; Valle, José W F

    1998-01-01

    We discuss the impact of recent experimental results on the determination of atmospheric neutrino oscillation parameters. We use all published results on atmospheric neutrinos, including the preliminary large statistics data of Super-Kamiokande. We re-analyze the data in terms of both $\

  3. Similarity interference in learning and retrieving arithmetic facts.

    Science.gov (United States)

    De Visscher, A; Noël, M-P

    2016-01-01

    Storing the solution of simple calculations in long-term memory is an important learning in primary school that is subsequently essential in adult daily living. While most children succeed in storing arithmetic facts to which they have been trained at school, huge individual differences are reported, particularly in children with developmental dyscalculia, who show a severe and persistent deficit in arithmetic facts learning. This chapter reports important advances in the understanding of the development of an arithmetic facts network and focuses on the detrimental effect of similarity interference. First, at the retrieval stage, connectionist models highlighted that the similarity of the neighbor problems in the arithmetic facts network creates interference. More recently, the similarity interference during the learning stage was pointed out in arithmetic facts learning. The interference parameter, that captures the proactive interference that a problem receives from previously learned problems, was shown as a substantial determinant of the performance across multiplication problems. This proactive interference was found both in children and adults and showed that when a problem is highly similar to previously learned ones, it is more difficult to remember it. Furthermore, the sensitivity to this similarity interference determined individual differences in the learning and retrieving of arithmetic facts, giving new insights for interindividual differences. Regarding the atypical development, hypersensitivity-to-interference in memory was related to arithmetic facts deficit in a single case of developmental dyscalculia and in a group of fourth-grade children with low arithmetic facts knowledge. In sum, the impact of similarity interference is shown in the learning stage of arithmetic facts and concerns the typical and atypical development.

  4. Analysis of Radio Frequency Blackout for a Blunt-Body Capsule in Atmospheric Reentry Missions

    OpenAIRE

    Yusuke Takahashi; Reo Nakasato; Nobuyuki Oshima

    2016-01-01

    A numerical analysis of electromagnetic waves around the atmospheric reentry demonstrator (ARD) of the European Space Agency (ESA) in an atmospheric reentry mission was conducted. During the ARD mission, which involves a 70% scaled-down configuration capsule of the Apollo command module, radio frequency blackout and strong plasma attenuation of radio waves in communications with data relay satellites and air planes were observed. The electromagnetic interference was caused by highly dense pla...

  5. Unreliability of triglyceride measurement to predict turbidity induced interference.

    Science.gov (United States)

    Twomey, P J; Don-Wauchope, A C; McCullough, D

    2003-11-01

    Lipaemic specimens are a common problem in clinical chemistry. Most laboratories will measure the concentration of triglycerides and then decide whether the analytical result is valid or not. There is a poor association between the concentration of triglycerides and an objective assessment of turbidity for visually turbid specimens. Extrapolation of triglyceride concentrations derived from the use of intravenous emulsions to visually turbid specimens found in clinical practice will overestimate the turbidity induced interference in assays (non-turbid interferences are probably the same). The evaluation of turbidity induced interference needs to be standardised using objective assessments of turbidity.

  6. Interference Imaging of Refractive Index Distribution in Thin Samples

    Directory of Open Access Journals (Sweden)

    Norbert Tarjanyi

    2004-01-01

    Full Text Available There are three versions of interference imaging of refractive index distribution in thin samples suggested in this contribution. These are based on imaging of interference field created by waves reflected from the front and the back sample surface or imaging of interference field of Michelson or Mach-Zehnder interferometer with the sample put in one of the interferometers arm. The work discusses the advantages and disadvantages of these techniques and presents the results of imaging of refrective index distribution in photorefractive record of a quasi-harmonic optical field in thin LiNbO3 crystal sample.

  7. Coherent Population Trapping-Ramsey Interference in Cold Atoms

    Institute of Scientific and Technical Information of China (English)

    CHEN Xi; YANG Guo-Qing; WANG Jin; ZHAN Ming-Sheng

    2010-01-01

    @@ We demonstrate an experimental observation of coherent population trapping-Ramsey interference in cold 87Rb atoms by employing the time-domain separated oscillatory fields' method. The interference fringe with line width of 80Hz is obtained. We propose a novel method to measure the cold atom number. The measurement is insensitive to the pump beam intensity, the single photon detuning and even the initial state population. We use this method to normalize the interference signal and to improve the signal-to-noise ratio significantly.

  8. Power allocation scheme for multicell interference coordination in OFDMA systems

    Institute of Scientific and Technical Information of China (English)

    Zhiwei LI; Chunyan FENG; Tiankui ZHANG; Jieying ZHENG

    2009-01-01

    To coordinate inter-cell interference,a multicell adaptive power allocation scheme is proposed for down-link orthogonal frequency division multiple access (OFDMA) cellular systems.This scheme uses the difference of the signal to interference plus noise ratio (SINR) between the co-subchannels of adjacent cells to balance SINR for coordinating the transmit power in the co-subchannels.The scheme can improve edge user performance,reduce interference between the co-subchannels of adjacent cells and improve radio resource utility.Simulation results show that the scheme can balance system performance and ensure system throughput.

  9. Interference Effects in Strong-Field Dissociative Ionization

    CERN Document Server

    Yue, Lun

    2015-01-01

    We theoretically study dissociative ionization of H$_2^+$ exposed to strong linearly polarized few-cycle visible, near-infrared and midinfrared laser pulses. We find rich energy-sharing structures in the combined electron and nuclear kinetic energy spectra with features that are a priori at odds with simple energy conservation arguments. We explain the structures as interferences between wave packets released during different optical cycles, and during the same optical cycle, respectively. Both inter- and intracycle interference structures are clearly visible in the joint energy spectra. The shapes of the interference structures depend on the dynamics leading to the double continuum, and carry sub-femtosecond information.

  10. Secondary Electron Interference from Trigonal Warping in Clean Carbon Nanotubes

    Science.gov (United States)

    Dirnaichner, A.; del Valle, M.; Götz, K. J. G.; Schupp, F. J.; Paradiso, N.; Grifoni, M.; Strunk, Ch.; Hüttel, A. K.

    2016-10-01

    We investigate Fabry-Perot interference in an ultraclean carbon nanotube resonator. The conductance shows a clear superstructure superimposed onto conventional Fabry-Perot oscillations. A sliding average over the fast oscillations reveals a characteristic slow modulation of the conductance as a function of the gate voltage. We identify the origin of this secondary interference in intervalley and intravalley backscattering processes which involve wave vectors of different magnitude, reflecting the trigonal warping of the Dirac cones. As a consequence, the analysis of the secondary interference pattern allows us to estimate the chiral angle of the carbon nanotube.

  11. Quantum Interference and Entanglement Induced by Multiple Scattering of Light

    DEFF Research Database (Denmark)

    Ott, Johan Raunkjær; Mortensen, Asger; Lodahl, Peter

    2010-01-01

    We report on the effects of quantum interference induced by the transmission of an arbitrary number of optical quantum states through a multiple-scattering medium. We identify the role of quantum interference on the photon correlations and the degree of continuous variable entanglement between two...... output modes. It is shown that quantum interference survives averaging over all ensembles of disorder and manifests itself as increased photon correlations due to photon antibunching. Furthermore, the existence of continuous variable entanglement correlations in a volume speckle pattern is predicted. Our...

  12. Generation of 1D interference patterns of Bloch surface waves

    Science.gov (United States)

    Kadomina, E. A.; Bezus, E. A.; Doskolovich, L. L.

    2016-09-01

    Interference patterns of Bloch surface waves with a period that is significantly less than the wavelength of incident radiation are formed using dielectric diffraction gratings located on the surface of photonic crystal. The simulation based on electromagnetic diffraction theory is used to demonstrate the possibility of high-quality interference patterns due to resonant enhancement of higher evanescent diffraction orders related to the excitation of the Bloch surface waves. The contrast of the interference patterns is close to unity, and the period is less than the period of the diffraction structure by an order of magnitude.

  13. Observation of Quantum Interference between Separated Mechanical Oscillator Wave Packets.

    Science.gov (United States)

    Kienzler, D; Flühmann, C; Negnevitsky, V; Lo, H-Y; Marinelli, M; Nadlinger, D; Home, J P

    2016-04-01

    We directly observe the quantum interference between two well-separated trapped-ion mechanical oscillator wave packets. The superposed state is created from a spin-motion entangled state using a heralded measurement. Wave packet interference is observed through the energy eigenstate populations. We reconstruct the Wigner function of these states by introducing probe Hamiltonians which measure Fock state populations in displaced and squeezed bases. Squeezed-basis measurements with 8 dB squeezing allow the measurement of interference for Δα=15.6, corresponding to a distance of 240 nm between the two superposed wave packets.

  14. Time Interference Alignment via Delay Offset for Long Delay Networks

    CERN Document Server

    Blasco, Francisco Lazaro; Bauch, Gerhard

    2011-01-01

    Time Interference Alignment is a flavor of Interference Alignment that increases the network capacity by suitably staggering the transmission delays of the senders. In this work the analysis of the existing literature is generalized and the focus is on the computation of the dof for networks with randomly placed users in a n-dimensional Euclidean space. In the basic case without coordination among the transmitters analytical expressions of the sum dof can be derived. If the transmit delays are coordinated, in 20% of the cases time Interference Alignment yields additional dof with respect to orthogonal access schemes. The potential capacity improvements for satellite networks are also investigated.

  15. Interference of quantum states in electronic waveguides with impurities

    International Nuclear Information System (INIS)

    One investigated into effects of interference of propagating and localized states in quasi-dimensional electric waveguides containing attracting impurities (quantum points) of finite sizes. Matrix of electron scattering is calculated in terms of the Feshbach theory. It is shown that attracting impurities with finite sizes may initiate a series of the Fano asymmetric resonances in waveguide transparency. In this case, due to interference of electronic states, characteristics of resonances may oscillate at variation of impurity parameters. One determined conditions under which the effects of interference of electron waves results in collapse and swing of the Fano resonances

  16. Observation of interference between two molecular Bose-Einstein condensates

    Energy Technology Data Exchange (ETDEWEB)

    Kohstall, C; Riedl, S; Sanchez Guajardo, E R; Sidorenkov, L A; Hecker Denschlag, J; Grimm, R, E-mail: christoph.kohstall@uibk.ac.at [Institut fuer Experimentalphysik und Zentrum fuer Quantenphysik, Universitaet Innsbruck, 6020 Innsbruck (Austria)

    2011-06-15

    We have observed the interference between two Bose-Einstein condensates of weakly bound Feshbach molecules of fermionic {sup 6}Li atoms. Two condensates are prepared in a double-well trap and, after release from this trap, overlap in expansion. We detect a clear interference pattern that unambiguously demonstrates the de Broglie wavelength of molecules. We verify that only the condensate fraction shows interference. With increasing interaction strength, the pattern vanishes because elastic collisions during overlap remove particles from the condensate wave function. For strong interaction, the condensates do not penetrate each other as they collide hydrodynamically.

  17. Mean Interference in Hard-Core Wireless Networks

    CERN Document Server

    Haenggi, Martin

    2011-01-01

    Mat\\'ern hard core processes of types I and II are the point processes of choice to model concurrent transmitters in CSMA networks. We determine the mean interference observed at a node of the process and compare it with the mean interference in a Poisson point process of the same density. It turns out that despite the similarity of the two models, they behave rather differently. For type I, the excess interference (relative to the Poisson case) increases exponentially in the hard-core distance, while for type II, the gap never exceeds 1 dB.

  18. Chip-interleaved optical code division multiple access relying on a photon-counting iterative successive interference canceller for free-space optical channels.

    Science.gov (United States)

    Zhou, Xiaolin; Zheng, Xiaowei; Zhang, Rong; Hanzo, Lajos

    2013-07-01

    In this paper, we design a novel Poisson photon-counting based iterative successive interference cancellation (SIC) scheme for transmission over free-space optical (FSO) channels in the presence of both multiple access interference (MAI) as well as Gamma-Gamma atmospheric turbulence fading, shot-noise and background light. Our simulation results demonstrate that the proposed scheme exhibits a strong MAI suppression capability. Importantly, an order of magnitude of BER improvements may be achieved compared to the conventional chip-level optical code-division multiple-access (OCDMA) photon-counting detector.

  19. Analysis, prediction and control of radio frequency interference with respect to DSN

    Science.gov (United States)

    Degroot, N. F.

    1982-06-01

    Susceptibility modeling, prediction of radio frequency interference from satellites, operational radio frequency interference control, and international regulations are considered. The existing satellite interference prediction program DSIP2 is emphasized. A summary status evaluation and recommendations for future work are given.

  20. Optimal-sampling Active Interference Cancellation under the Minimax Criterion

    Directory of Open Access Journals (Sweden)

    Jinping Liu

    2014-05-01

    Full Text Available In industry and academia, researchers have given more and more attention to Cognitive Radio (CR. The key idea of CR is to make it possible for a wireless system to find the vacant spectrum and transfer data without interfering with licensed users (LUs. Then, OFDM is proposed as a candidate signaling technology for such applications. However, the sidelobe interference of subcarriers has become a problem. In this letter, a method for sidelobe suppressing in OFDM systems is proposed and investigated. The proposed method is based on sampling in optimal locations with optimal weights in Active Interference Cancellation (AIC. By means of this technique, the maximum interference of the target spectrum is minimized. The proposed method can be used to minimize the maximum interference to licensed users in OFDM-based cognitive radio systems. Additionally, this method can be combined with other algorithms, such as Cancellation Carriers (CCs and Subcarrier Weighting (SW, to enhance their performance under the minimax criterion.

  1. Tracking Launch Vehicles in Interference and Jamming Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MARK Resources proposes to develop a method for combining a set of distributed FRPAs into a network that provides high GPS anti-jam/interference capability. Like a...

  2. Occurrence and characteristics of mutual interference between LIDAR scanners

    Science.gov (United States)

    Kim, Gunzung; Eom, Jeongsook; Park, Seonghyeon; Park, Yongwan

    2015-05-01

    The LIDAR scanner is at the heart of object detection of the self-driving car. Mutual interference between LIDAR scanners has not been regarded as a problem because the percentage of vehicles equipped with LIDAR scanners was very rare. With the growing number of autonomous vehicle equipped with LIDAR scanner operated close to each other at the same time, the LIDAR scanner may receive laser pulses from other LIDAR scanners. In this paper, three types of experiments and their results are shown, according to the arrangement of two LIDAR scanners. We will show the probability that any LIDAR scanner will interfere mutually by considering spatial and temporal overlaps. It will present some typical mutual interference scenario and report an analysis of the interference mechanism.

  3. Ribonucleic acid interference (RNAi) and control of citrus pests

    Science.gov (United States)

    Ribonucleic acid interference, RNAi, applications and function are described for the non-scientist to bring a better understanding of how this emerging technology is providing environmentally friendly, non-transgenic, insect pest control. ...

  4. Electron Interference in Molecular Circular Polarization Attosecond XUV Photoionization

    Directory of Open Access Journals (Sweden)

    Kai-Jun Yuan

    2015-01-01

    Full Text Available Two-center electron interference in molecular attosecond photoionization processes is investigated from numerical solutions of time-dependent Schrödinger equations. Both symmetric H\\(_2^+\\ and nonsymmetric HHe\\(^{2+}\\ one electron diatomic systems are ionized by intense attosecond circularly polarized XUV laser pulses. Photoionization of these molecular ions shows signature of interference with double peaks (minima in molecular attosecond photoelectron energy spectra (MAPES at critical angles \\(\\vartheta_c\\ between the molecular \\(\\textbf{R}\\ axis and the photoelectron momentum \\(\\textbf{p}\\. The interferences are shown to be a function of the symmetry of electronic states and the interference patterns are sensitive to the molecular orientation and pulse polarization. Such sensitivity offers possibility for imaging of molecular structure and orbitals.

  5. Constructive interference via collision-aided radiative excitation

    Institute of Scientific and Technical Information of China (English)

    杨希华; 孙真荣; 丁良恩; 王祖赓

    2002-01-01

    We have studied theoretically constructive interference via collision-aided radiative excitation in an open fourlevel system using a density matrix approach. The four-level system consists of a A-type three-level quantum-beat configuration driven by one laser field and a fourth level coupled by a vacuum mode. It is shown that through the incoherent process (collision), coherence between widely-separated doublets and subsequent constructive interference can be realized. We analyse the effects of the collisio-induced coherent and incoherent decay rates, laser intensity, and energy separation of the doublets on the interference.Meanwhile, the constructive interference between the two transition pathways 3P1/2-4D and 3P3/2-4D via equal-frequency hybrid excitation and collision-aided radiative excitation in an Na2-Na system is experimentally observed. A good agreement between the theoretical and experimental results is obtained.

  6. An exact factorization perspective on quantum interferences in nonadiabatic dynamics

    Science.gov (United States)

    Curchod, Basile F. E.; Agostini, Federica; Gross, E. K. U.

    2016-07-01

    Nonadiabatic quantum interferences emerge whenever nuclear wavefunctions in different electronic states meet and interact in a nonadiabatic region. In this work, we analyze how nonadiabatic quantum interferences translate in the context of the exact factorization of the molecular wavefunction. In particular, we focus our attention on the shape of the time-dependent potential energy surface—the exact surface on which the nuclear dynamics takes place. We use a one-dimensional exactly solvable model to reproduce different conditions for quantum interferences, whose characteristic features already appear in one-dimension. The time-dependent potential energy surface develops complex features when strong interferences are present, in clear contrast to the observed behavior in simple nonadiabatic crossing cases. Nevertheless, independent classical trajectories propagated on the exact time-dependent potential energy surface reasonably conserve a distribution in configuration space that mimics one of the exact nuclear probability densities.

  7. An Exact Factorization Perspective on Quantum Interferences in Nonadiabatic Dynamics

    CERN Document Server

    Curchod, Basile F E; Gross, E K U

    2016-01-01

    Nonadiabatic quantum interferences emerge whenever nuclear wavefunctions in different electronic states meet and interact in a nonadiabatic region. In this work, we analyze how nonadiabatic quantum interferences translate in the context of the exact factorization of the molecular wavefunction. In particular, we focus our attention on the shape of the time-dependent potential energy surface - the exact surface on which the nuclear dynamics takes place - using an exactly-solvable model to reproduce different conditions for quantum interferences. The time-dependent potential energy surface develops complex features when strong interferences are present, in clear contrast to the observed behavior in simple nonadiabatic crossing cases. Nevertheless, independent classical trajectories propagated on the exact time-dependent potential energy surface reasonably conserve a distribution in configuration space that mimics the one of the exact nuclear probability density.

  8. ULS (ULtra-small angle Scattering instrument) and interference imaging

    International Nuclear Information System (INIS)

    The cold neutron beam port C1-3, ULS (ULtra Small angle scattering instrument) has been designed and built for the ultra-small angle scattering using a pair of Si-perfect crystals, neutron interferometry with Si-perfect crystal, double-crystal method to estimate the perfection of crystals. For these years, this beam port is used for the development of neutron interference imaging. The neutron interference imaging technique has been developed for these years with several methods. These years we are developing neutron interference imaging technique using gratings at ULS. The neutron interference imaging experiment with two absorption gratings has been done. We develop new way to fabricate absorption gratings for neutron with the pitch of 150 μm, 180 μm, and 200 μm. Small break in an acrylic plate was observed. (author)

  9. Virtual moire interference approach for an industrial safety monitoring system

    Science.gov (United States)

    Hamza, Rida; Cofer, Darren

    2001-10-01

    The objective of this work was to determine the feasibility and reliability of using the moire interference phenomenon as a means to detect human intrusion within a monitored zone. We applied moire interference principle for use in low-cost, safety-critical industrial monitoring applications. Moire interference is usually applied in the context of industrial applications for shape measurements. In this framework, we show how we can apply this concept to build a new safety product that detects human intrusion into dangerous areas on the factory floor. We demonstrate that a solution based on moire interference offers the potential for detection true 3D objects while preventing false alarms due to lighting variations or shadows and simplifying the image processing software. In addition, our prosed approach is advantageous in the product certification process because it is an active detection method.

  10. Interference Reduction Technique in WCDMA using Cell Resizing

    Directory of Open Access Journals (Sweden)

    N.Mohan

    2012-07-01

    Full Text Available In WCDMA, the interference is produced by different factors such as thermal noise, intra cell traffic, traffic in adjacent cells and external traffic. In addition, the increase in number of users in a cell consequently increases the total interference in the network. Hence, the interference must be controlled to improve the throughput of the network. In this paper, we propose an Interference Revocation Technique in WCDMA using Cell Resizing approach. Our technique classifies the access points into three types as normal, saturated and cooperative based on its signal to noise ratio (SNR. The saturated cell triggers the process of cell resizing. This process balances the number of users in each cell and thereby cancels theinterference completely. We prove the efficiency of our technique through simulation results.

  11. Experimental evidence for cryptic interference among socially foraging shorebirds

    NARCIS (Netherlands)

    Bijleveld, A.I.; Folmer, E.O.; Piersma, T.

    2012-01-01

    Foraging rate and the distribution of foragers depend on prey distribution in conjunction with interindividual interactions. Generalized functional response models predict intake rates and spatial distributions of foragers on the basis of resource distribution and interference competition. The adequ

  12. Control of the differential interference contrast in reinjected bimode laser

    CERN Document Server

    Lacot, Eric; Hugon, Olivier; de Chatellus, Hugues Guillet

    2016-01-01

    We have demonstrated, both theoretically and experimentally, that it is possible to control (i.e., to enhance or cancel) the contrast of the interference pattern appearing in the intensity images obtained with a laser optical feedback imaging (LOFI) setup using a bimode laser. The laser is composed of two coupled orthogonally polarized states that interact (i.e., interfere) through the cross saturation laser dynamics. We created the contrast control by choosing the frequency shift (i.e., the beating frequency) between the feedback electric fields and the intracavity electric fields. We have shown that the interference contrast of the output power modulation of the laser total intensity is independent from the frequency shift and is always maximal. On the other hand, the interference contrast of each polarization state is frequency dependent. We obtained the maximal contrast when the frequency shift was equal to one of the resonance frequencies of the bimode dynamics, and was very low (and almost cancels) for ...

  13. Advances in the analysis of pressure interference tests

    Energy Technology Data Exchange (ETDEWEB)

    Martinez R, N. [Petroleos Mexicanos, PEMEX, Mexico City (Mexico); Samaniego V, F. [Univ. Nacional Autonoma de Mexico (Mexico)

    2010-12-15

    This paper presented an extension for radial, linear, and spherical flow conditions of the El-Khatib method for analyzing pressure interference tests through utilization of the pressure derivative. Conventional analysis of interference tests considers only radial flow, but some reservoirs have physical field conditions in which linear or spherical flow conditions prevail. The INTERFERAN system, a friendly computer code for the automatic analysis of pressure interference tests, was also discussed and demonstrated by way of 2 field cases. INTERFERAN relies on the principle of superposition in time and space to interpret a test of several wells with variable histories of production or injection or both. The first field case addressed interference tests conducted in the naturally fractured geothermal field of Klamath Falls, and the second field case was conducted in a river-formed bed in which linear flow conditions are dominant. The analysis was deemed to be reliable. 13 refs., 1 tab., 7 figs.

  14. Electromagnetic interferences from plasmas generated in meteoroids impacts

    CERN Document Server

    Foschini, L

    1998-01-01

    It is shown that the plasma, generated during an impact of a meteoroid with an artificial satellite, can produce electromagnetic radiations below the microwave frequency range. These interferences can disturb the regular satellite operations.

  15. Momentum mapping of continuum electron wave packet interference

    CERN Document Server

    Yang, Weifeng; Lin, Cheng; Xu, Jingwen; Sheng, Zhihao; Song, Xiaohong; Hu, Shilin; Chen, Jing

    2016-01-01

    We analyze the two-dimensional photoelectrons momentum distribution of Ar atom ionized by midinfrared laser pulses and mainly concentrate on the energy range below 2Up. By using a generalized quantum trajectory Monte Carlo (GQTMC) simulation and comparing with the numerical solution of time-dependent Schrodinger equation (TDSE), we show that in the deep tunneling regime, the rescattered electron trajectories plays unimportant role and the interplay between the intracycle and inter-cycle results in a ring-like interference pattern. The ring-like interference pattern will mask the holographic interference structure in the low longitudinal momentum region. When the nonadiabatic tunneling contributes significantly to ionization, i.e., the Keldysh parameter 1, the contribution of the rescattered electron trajectories become large, thus holographic interference pattern can be clearly observed. Our results help paving the way for gaining physical insight into ultrafast electron dynamic process with attosecond tempor...

  16. Quantum interference of molecules -- probing the wave nature of matter

    CERN Document Server

    Venugopalan, Anu

    2012-01-01

    The double slit interference experiment has been famously described by Richard Feynman as containing the "only mystery of quantum mechanics". The history of quantum mechanics is intimately linked with the discovery of the dual nature of matter and radiation. While the double slit experiment for light is easily undertsood in terms of its wave nature, the very same experiment for particles like the electron is somewhat more difficult to comprehend. By the 1920s it was firmly established that electrons have a wave nature. However, for a very long time, most discussions pertaining to interference experiments for particles were merely gedanken experiments. It took almost six decades after the establishment of its wave nature to carry out a 'double slit interference' experiment for electrons. This set the stage for interference experiments with larger particles. In the last decade there has been spectacular progress in matter-wave interefernce experiments. Today, molecules with over a hundred atoms can be made to i...

  17. An update on mobile phones interference with medical devices.

    Science.gov (United States)

    Mahmoud Pashazadeh, Ali; Aghajani, Mahdi; Nabipour, Iraj; Assadi, Majid

    2013-10-01

    Mobile phones' electromagnetic interference with medical devices is an important issue for the medical safety of patients who are using life-supporting medical devices. This review mainly focuses on mobile phones' interference with implanted medical devices and with medical equipment located in critical areas of hospitals. A close look at the findings reveals that mobile phones may adversely affect the functioning of medical devices, and the specific effect and the degree of interference depend on the applied technology and the separation distance. According to the studies' findings and the authors' recommendations, besides mitigating interference, using mobile phones at a reasonable distance from medical devices and developing technology standards can lead to their effective use in hospital communication systems.

  18. Mutual Interference of Frequency Hopping with Collision Avoidance Systems

    Directory of Open Access Journals (Sweden)

    R. Pust

    2012-04-01

    Full Text Available The aim of this article is to quantify and analyze mutual interference of Frequency Hopping with Collision Avoidance (FH/CA systems. The FH/CA system is a frequency hopping system where stations select the least jammed channel from several possible before the next jump. The article describes a mathematical model that allows determining the upper limit of the probability of collision of multiple FH/CA systems operated in a common band. The dependence obtained for mutual interference of FH/CA systems is compared with the dependence for mutual interference of conventional FH systems. The result of the comparison is a conclusion that, in terms of mutual interference, it is more advantageous to operate the FH/CA systems than the conventional FH systems.

  19. Maximum MIMO System Mutual Information with Antenna Selection and Interference

    Directory of Open Access Journals (Sweden)

    Rick S. Blum

    2004-05-01

    Full Text Available Maximum system mutual information is considered for a group of interfering users employing single user detection and antenna selection of multiple transmit and receive antennas for flat Rayleigh fading channels with independent fading coefficients for each path. In the case considered, the only feedback of channel state information to the transmitter is that required for antenna selection, but channel state information is assumed at the receiver. The focus is on extreme cases with very weak interference or very strong interference. It is shown that the optimum signaling covariance matrix is sometimes different from the standard scaled identity matrix. In fact, this is true even for cases without interference if SNR is sufficiently weak. Further, the scaled identity matrix is actually that covariance matrix that yields worst performance if the interference is sufficiently strong.

  20. An exact factorization perspective on quantum interferences in nonadiabatic dynamics.

    Science.gov (United States)

    Curchod, Basile F E; Agostini, Federica; Gross, E K U

    2016-07-21

    Nonadiabatic quantum interferences emerge whenever nuclear wavefunctions in different electronic states meet and interact in a nonadiabatic region. In this work, we analyze how nonadiabatic quantum interferences translate in the context of the exact factorization of the molecular wavefunction. In particular, we focus our attention on the shape of the time-dependent potential energy surface-the exact surface on which the nuclear dynamics takes place. We use a one-dimensional exactly solvable model to reproduce different conditions for quantum interferences, whose characteristic features already appear in one-dimension. The time-dependent potential energy surface develops complex features when strong interferences are present, in clear contrast to the observed behavior in simple nonadiabatic crossing cases. Nevertheless, independent classical trajectories propagated on the exact time-dependent potential energy surface reasonably conserve a distribution in configuration space that mimics one of the exact nuclear probability densities. PMID:27448870

  1. Glacial atmospheric phosphorus deposition

    Science.gov (United States)

    Kjær, Helle Astrid; Dallmayr, Remi; Gabrieli, Jacopo; Goto-Azuma, Kumiko; Hirabayashi, Motohiro; Svensson, Anders; Vallelonga, Paul

    2016-04-01

    Phosphorus in the atmosphere is poorly studied and thus not much is known about atmospheric phosphorus and phosphate transport and deposition changes over time, though it is well known that phosphorus can be a source of long-range nutrient transport, e.g. Saharan dust transported to the tropical forests of Brazil. In glacial times it has been speculated that transport of phosphorus from exposed shelves would increase the ocean productivity by wash out. However whether the exposed shelf would also increase the atmospheric load to more remote places has not been investigated. Polar ice cores offer a unique opportunity to study the atmospheric transport of aerosols on various timescales, from glacial-interglacial periods to recent anthropogenic influences. We have for the first time determined the atmospheric transport of phosphorus to the Arctic by means of ice core analysis. Both total and dissolved reactive phosphorus were measured to investigate current and past atmospheric transport of phosphorus to the Arctic. Results show that glacial cold stadials had increased atmospheric total phosphorus mass loads of 70 times higher than in the past century, while DRP was only increased by a factor of 14. In the recent period we find evidence of a phosphorus increase over the past 50 yrs in ice cores close to human occupation likely correlated to forest fires. References: Kjær, Helle Astrid, et al. "Continuous flow analysis method for determination of dissolved reactive phosphorus in ice cores." Environmental science & technology 47.21 (2013): 12325-12332. Kjær, Helle Astrid, et al. "Greenland ice cores constrain glacial atmospheric fluxes of phosphorus." Journal of Geophysical Research: Atmospheres120.20 (2015).

  2. Two instruments based on differential optical absorption spectroscopy (DOAS) to measure accurate ammonia concentrations in the atmosphere

    OpenAIRE

    H. Volten; Bergwerff, J.B.; M. Haaima; Lolkema, D. E.; A. J. C. Berkhout; G. R. van der Hoff; C. J. M. Potma; R. J. Wichink Kruit; W. A. J. van Pul; D. P. J. Swart

    2011-01-01

    We present two Differential Optical Absorption Spectroscopy (DOAS) instruments built at RIVM: the RIVM DOAS and the miniDOAS. Both instruments provide virtually interference-free measurements of NH3 concentrations in the atmosphere, since they measure over an open path, without suffering from inlet problems or interference problems by ammonium aerosols dissociating on tubes or filters. They measure concentrations up to at least 200 μg m−3, have a ...

  3. Interference Visibility as a Witness of Entanglement and Quantum Correlation

    OpenAIRE

    Zhang, Lin; Pati, Arun Kumar; Wu, Junde

    2014-01-01

    In quantum information and communication one looks for the non-classical features like interference and quantum correlations to harness the true power of composite systems. We show how the concept akin to interference is, in fact, intertwined in a quantitative manner to entanglement and quantum correlation. In particular, we prove that the difference in the squared visibility for a density operator before and after a complete measurement, averaged over all unitary evolutions, is directly rela...

  4. Quantum Interference Effects in Electronic Transport through Nanotube Contacts

    OpenAIRE

    Buia, Calin; Buldum, Alper; Lu, Jian Ping

    2002-01-01

    Quantum interference has dramatic effects on electronic transport through nanotube contacts. In optimal configuration the intertube conductance can approach that of a perfect nanotube ($4e^2/h$). The maximum conductance increases rapidly with the contact length up to 10 nm, beyond which it exhibits long wavelength oscillations. This is attributed to the resonant cavity-like interference phenomena in the contact region. For two concentric nanotubes symmetry breaking reduces the maximum intertu...

  5. Differential Reprogramming Based on Constructive Interference for Wireless Sensor Network

    OpenAIRE

    Hu, Bing

    2016-01-01

    To improve the performance of reprogramming in wireless sensor network, we present a novel reprogramming structure and constructive interference-based dissemination protocol (CIDP) to transmit the patch through out the network fast and reliability. CIDP disseminates the patch, which is divided into several packets, to the network exploiting constructive interference. We evaluate our implementation of CIDP using simulation under different number of nodes. Our results show that CIDP disseminate...

  6. Grounding Effect on Common Mode Interference of Underground Inverter

    OpenAIRE

    Cheng, Qiang; Cheng, Ning; LI Zhen-shuang

    2013-01-01

    For the neutral point not grounded characteristics of underground power supply system in coal mine, this paper studied common mode equivalent circuit of underground PWM inverter, and extracted parasitic parameters of interference propagation path. The author established a common mode and differential mode model of underground inverter. Taking into account the rise time of PWM, the simulation results of conducted interference by Matlab software is compared with measurement spectrum on the AC s...

  7. Precise packet loss pattern generation by intentional interference

    OpenAIRE

    He Z.; Voigt T

    2011-01-01

    Abstract—Intermediate-quality links often cause vulnerable connectivity in wireless sensor networks, but packet losses caused by such volatile links are not easy to trace. In order to equip link layer protocol designers with a reliable test and debugging tool, we develop a reactive interferer to generate packet loss patterns precisely. By using intentional interference to emulate parameterized lossy links with very low intrusiveness, our tool facilitates both robustness evaluation of proto...

  8. Quantum interference vs. quantum chaos in the nuclear shell model

    International Nuclear Information System (INIS)

    In this paper we study the complexity of the nuclear states in terms of a two body quadupole-quadrupole interaction. Energy distributions and eigenvectors composition exhibit a visible interference pattern which is dependent on the intensity of the interaction. In analogy with optics, the visibility of the interference is related to the purity of the states, therefore, we show that the fluctuations associated with quantum chaos have as their origin the remaining quantum coherence with a visibility magnitude close to 5%

  9. Optimal Gathering Protocols on Paths under Interference Constraints

    OpenAIRE

    Bermond, Jean-Claude; Correa, Ricardo; Yu, Min-Li

    2009-01-01

    A preliminary version has been presented at CIAC06 International audience We study the problem of gathering information from the nodes of a multi-hop radio network into a predefined destination node under reachability and interference constraints. In such a network, a node is able to send messages to other nodes within reception distance, but doing so it might create interference with other communications. Thus, a message can only be properly received if the receiver is reachable from t...

  10. Diversity-Multiplexing Tradeoff in Fading Interference Channels

    OpenAIRE

    Akcaba, Cemal; Boelcskei, Helmut

    2009-01-01

    We analyze two-user single-antenna fading interference channels with perfect receive channel state information (CSI) and no transmit CSI. We compute the diversity-multiplexing tradeoff (DMT) region of a fixed-power-split Han and Kobayashi (HK)-type superposition coding scheme and provide design criteria for the corresponding superposition codes. We demonstrate that this scheme is DMT-optimal under moderate, strong, and very strong interference by showing that it achieves a DMT outer bound tha...

  11. General relativistic effects in quantum interference of "clocks"

    CERN Document Server

    Zych, Magdalena; Costa, Fabio; Brukner, Časlav

    2016-01-01

    Quantum mechanics and general relativity have been each successfully tested in numerous experiments. However, the regime where both theories are jointly required to explain physical phenomena remains untested by laboratory experiments, and is also not fully understood by theory. This contribution reviews recent ideas for a new type of experiments: quantum interference of "clocks", which aim to test novel quantum effects that arise from time dilation. "Clock" interference experiments could be realised with atoms or photons in near future laboratory experiments.

  12. Cross-conjugation and quantum interference: a general correlation?

    DEFF Research Database (Denmark)

    Valkenier, Hennie; Guedon, Constant M.; Markussen, Troels;

    2014-01-01

    We discuss the relationship between the pi-conjugation pattern, molecular length, and charge transport properties of molecular wires, both from an experimental and a theoretical viewpoint. Specifically, we focus on the role of quantum interference in the conductance properties of cross-conjugated...... interference occurs can be tuned by the choice of side group. The latter provides an outlook for future devices in this fascinating field connecting chemistry and physics....

  13. Interference scattering effects on intermediate resonance absorption at operating temperatures

    International Nuclear Information System (INIS)

    Resonance integrals may be accurately calculated using the intermediate resonance (IR) approximation. Results are summarized for the case of an absorber with given potential scattering cross sections and interference scattering parameter admixed with a non absorbing moderator of given cross section and located in a narrow resonance moderating medium. From the form of the IR solutions, it is possible to make some general observations about effects of interference scattering on resonance absorption. 2 figures

  14. Inference for deformation and interference in 3D printing

    OpenAIRE

    Sabbaghi, Arman; Dasgupta, Tirthankar; Huang, Qiang; Zhang, Jizhe

    2014-01-01

    Additive manufacturing, or 3D printing, is a promising manufacturing technique marred by product deformation due to material solidification in the printing process. Control of printed product deformation can be achieved by a compensation plan. However, little attention has been paid to interference in compensation, which is thought to result from the inevitable discretization of a compensation plan. We investigate interference with an experiment involving the application of discretized compen...

  15. The relationship between target quality and interference in sound zones

    OpenAIRE

    Baykaner, K; Coleman, P.; Mason, R.; Jackson, PJB; Francombe, J; Olik, M; Bech, S

    2015-01-01

    Sound zone systems aim to produce regions within a room where listeners may consume separate audio programs with minimal acoustical interference. Often, there is a trade-off between the acoustic contrast achieved between the zones, and the fidelity of the reproduced audio program (the target quality). An open question is whether reducing contrast (i.e. allowing greater interference) can improve target quality. The planarity control sound zoning method can be used to improve spatial reproducti...

  16. Sex differences in coping with work-home interference

    OpenAIRE

    Beauregard, T. Alexandra

    2009-01-01

    This chapter seeks to extend existing research on work-home coping in several ways. First, it investigates the effects on interference of a wider range of coping strategies than those previously addressed in the work-home literature. Secondly, it takes into account both directions of work-home interference. Finally, this study examines the effect of sex on the effectiveness of coping mechanisms, as dissimilar expectations of men and women in the workplace and at home may influence the ability...

  17. An Automatic Interference Recognition Method in Spread Spectrum Communication System

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-ming; TAO Ran

    2007-01-01

    An algorithm to detect and recognize interferences embedded in a direct sequence spread spectrum (DSSS) communication system is proposed. Based on Welch's averaging modified periodogram method and fractional Fourier transformation (FRFT), the paper proposes a decision tree-based algorithm in which a set of decision criteria for identifying different types of interferences is developed. Simulation results demonstrate that the proposed algorithm provides a high recognition rate and is robust for various ISR and SNR.

  18. Cyclostationary Model Based Multiple-Tone Interference Rejection in DSSS Communication Systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Multiple-tone interference is a kind of narrow band interference appears in Direct Sequence (DS) Spread Spectrum (SS) communication system frequently that degrades the system performance. Most open literature studies on narrowband interference rejection assumed stationary SS signal and interference. SS signal and interference are modeled as cyclostationary and based on cyclostationary model, an interference rejection algorithm is proposed. Through computer simulation, it is shown that the performance of the SS system can be improved considerably after adopting this algorithm.

  19. LC-MS/MS bioanalytical method development for AMG 900: resolution of an isobaric interference in rodent in vivo studies.

    Science.gov (United States)

    Be, Xuhai; Moore, Earl S; Zhao, Zhiyang; Wells, Mary C

    2013-02-23

    AMG 900 is an orally available small molecule that is a highly potent and selective pan-aurora kinase inhibitor currently in development for the treatment of advanced human cancers. A co-eluting, isobaric interference was discovered in preliminary LC-MS/MS analyses of rodent in vivo pharmacokinetic samples during preclinical evaluation of AMG 900. The interference was identified as a major circulating N-oxide metabolite which partially converted to an [M+H-O](+) ion under the conditions of atmospheric pressure chemical ionization. A selective liquid chromatography-tandem mass spectrometry method for the simultaneous quantification of AMG 900 and its N-oxide metabolite in plasma was developed and successfully applied for the bioanalysis of discovery stage preclinical rodent pharmacokinetic studies.

  20. The role of quantum interference and partial redistribution in the solar Ba II D2 4554 A line

    CERN Document Server

    Smitha, H N; Stenflo, J O; Sampoorna, M

    2014-01-01

    The Ba II D2 line at 4554 A is a good example, where the F-state interference effects due to the odd isotopes produce polarization profiles, which are very different from those of the even isotopes that do not exhibit F-state interference. It is therefore necessary to account for the contributions from the different isotopes to understand the observed linear polarization profiles of this line. In this paper we present radiative transfer modeling with partial frequency redistribution (PRD), which is shown to be essential to model this line. This is because complete frequency redistribution (CRD) cannot reproduce the observed wing polarization. We present the observed and computed Q/I profiles at different limb distances. The theoretical profiles strongly depend on limb distance (\\mu) and the model atmosphere which fits the limb observations fails at other \\mu\\ positions.

  1. Investigation of Interference Models for RFID Systems †

    Science.gov (United States)

    Zhang, Linchao; Ferrero, Renato; Gandino, Filippo; Rebaudengo, Maurizio

    2016-01-01

    The reader-to-reader collision in an RFID system is a challenging problem for communications technology. In order to model the interference between RFID readers, different interference models have been proposed, mainly based on two approaches: single and additive interference. The former only considers the interference from one reader within a certain range, whereas the latter takes into account the sum of all of the simultaneous interferences in order to emulate a more realistic behavior. Although the difference between the two approaches has been theoretically analyzed in previous research, their effects on the estimated performance of the reader-to-reader anti-collision protocols have not yet been investigated. In this paper, the influence of the interference model on the anti-collision protocols is studied by simulating a representative state-of-the-art protocol. The results presented in this paper highlight that the use of additive models, although more computationally intensive, is mandatory to improve the performance of anti-collision protocols. PMID:26861326

  2. Imperfect generalized transmit beamforming with co-channel interference cancelation

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2010-10-01

    The performance of a generalized single-stream transmit beamforming scheme employing receive co-channel interference -steering algorithms in slowly varying and flat fading channels is analyzed. The impact of imperfect prediction of channel state information (CSI) for the desired user spatially uncorrelated transmit channels is considered. Both dominant interference cancelation and adaptive arbitrary interference cancelation algorithms for closely spaced receive antennas are used. The impact of outdated statistical ordering of the interferers instantaneous powers on the effectiveness of dominant interference cancelation is investigated against the less complex adaptive arbitrary cancelation scheme. For the system models described above, new exact formulas for the statistics of combined signal-to-interference-plus-noise ratio (SINR) are derived, from which results for conventional maximum ratio transmission (MRT) and best transmit channel selection schemes can be deduced as limiting cases. The results presented herein can be used to obtain quantitative measure for various performance metrics, and in addition to investigate the performance-complexity tradeoff for different multiple-antenna system models. © 2010 IEEE.

  3. Interference Mitigation Techniques for Spectral Capacity Enhancement in GSM Networks

    Directory of Open Access Journals (Sweden)

    Ahmed M. Alaa

    2014-01-01

    Full Text Available Random Frequency Hopping (FH is a key feature of GSM networks that allows for capacity enhancement. The increased co-channel interference experienced in networks with tight frequency reuse schemes can be mitigated by adopting frequency hopping. Frequency hopping diversifies the interference signals over sparse transmitted bursts. This effect is called Interference Diversity. Interference Diversity allows the Forward Error Correcting codes (FEC to easily correct the corrupted bits. Thus, frequency hopping allows the network operator to use a tighter frequency reuse scheme without exhibiting higher levels of co-channel interference. Discontinuous Transmission (DTX is another interference mitigation method that utilizes the user’s silence frames to reduce the transmitted power, while Power Control (PC links the transmitted handset power with its relative distance from the Base Station (BTS. In this work, we study the impact of random FH, DTX and PC on the Spectral Capacity of GSM cellular networks by means of combined link level and system level simulation. It is shown that a spectral capacity gain is obtained in a 3/9 reuse scheme that deploys PC, DTX and FH compared to a conventional 4/12 reuse scheme.

  4. Cross Layer Interference Management in Wireless Biomedical Networks

    Directory of Open Access Journals (Sweden)

    Emmanouil G. Spanakis

    2014-04-01

    Full Text Available Interference, in wireless networks, is a central phenomenon when multiple uncoordinated links share a common communication medium. The study of the interference channel was initiated by Shannon in 1961 and since then this problem has been thoroughly elaborated at the Information theoretic level but its characterization still remains an open issue. When multiple uncoordinated links share a common medium the effect of interference is a crucial limiting factor for network performance. In this work, using cross layer cooperative communication techniques, we study how to compensate interference in the context of wireless biomedical networks, where many links transferring biomedical or other health related data may be formed and suffer from all other interfering transmissions, to allow successful receptions and improve the overall network performance. We define the interference limited communication range to be the critical communication region around a receiver, with a number of surrounding interfering nodes, within which a successful communication link can be formed. Our results indicate that we can achieve more successful transmissions by adapting the transmission rate and power, to the path loss exponent, and the selected mode of the underline communication technique allowing interference mitigation and when possible lower power consumption and increase achievable transmission rates.

  5. CONTEXTUAL INTERFERENCE AND INTROVERSION/EXTRAVERSION IN MOTOR LEARNING.

    Science.gov (United States)

    Meira, Cassio M; Fairbrother, Jeffrey T; Perez, Carlos R

    2015-10-01

    The Introversion/Extraversion dimension may interact with contextual interference, as random and blocked practice schedules imply distinct levels of variation. This study investigated the effect of different practice schedules in the acquisition of a motor skill in extraverts and introverts. Forty male undergraduate students (M = 24.3 yr., SD = 5.6) were classified as extraverts (n = 20) and introverts (n = 20) by the Eysenck Personality Questionnaire and allocated in one of two practice schedules with different levels of contextual interference: blocked (low contextual interference) and random (high contextual interference). Half of each group was assigned to a blocked practice schedule, and the other half was assigned to a random practice schedule. The design had two phases: acquisition and transfer (5 min. and 24 hr.). The participants learned variations of a sequential timing keypressing task. Each variation required the same sequence but different timing; three variations were used in acquisition, and one variation of intermediate length was used in transfer. Results for absolute error and overall timing error (root mean square error) indicated that the contextual interference effect was more pronounced for introverts. In addition, introverts who practiced according to the blocked schedule committed more errors during the 24-hr. transfer, suggesting that introverts did not appear to be challenged by a low contextual interference practice schedule. PMID:26447746

  6. Interference effects between manual and oral motor skills.

    Science.gov (United States)

    Gagné, Marie-Hélène; Cohen, Henri

    2016-03-01

    Consolidation of a motor skill is characterized by spontaneous improvement in performance between practice sessions. These offline gains can be eliminated if another skill is introduced soon afterward-a phenomenon called retroactive interference. Interference effects have been found in studies using two similar tasks involving the same motor effectors in a manual mode. The present study aimed to determine the extent to which differences in motor production mode modulate interference in skill learning. Healthy participants were assigned to one of three conditions and trained on a finger opposition sequence (FOS) learning task. All subjects were tested 24 h later on the original FOS learning task. Control subjects who were not exposed to a secondary learning task exhibited the expected offline gains after 24 h. Subjects who immediately learned a secondary task after the FOS training, either in the same manual mode (French Sign Language) or in an oral mode (CVC syllables), did not show any offline gains. Interestingly, the amount of interference was equivalent in the manual and oral learning conditions. The results reveal that interference effects in motor skill learning can occur when different effectors are involved in the primary and secondary tasks. The sequence processing abilities of the basal ganglia appear to play a major role in these interference effects. PMID:26661336

  7. CRISPR interference and priming varies with individual spacer sequences.

    Science.gov (United States)

    Xue, Chaoyou; Seetharam, Arun S; Musharova, Olga; Severinov, Konstantin; Brouns, Stan J J; Severin, Andrew J; Sashital, Dipali G

    2015-12-15

    CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR associated) systems allow bacteria to adapt to infection by acquiring 'spacer' sequences from invader DNA into genomic CRISPR loci. Cas proteins use RNAs derived from these loci to target cognate sequences for destruction through CRISPR interference. Mutations in the protospacer adjacent motif (PAM) and seed regions block interference but promote rapid 'primed' adaptation. Here, we use multiple spacer sequences to reexamine the PAM and seed sequence requirements for interference and priming in the Escherichia coli Type I-E CRISPR-Cas system. Surprisingly, CRISPR interference is far more tolerant of mutations in the seed and the PAM than previously reported, and this mutational tolerance, as well as priming activity, is highly dependent on spacer sequence. We identify a large number of functional PAMs that can promote interference, priming or both activities, depending on the associated spacer sequence. Functional PAMs are preferentially acquired during unprimed 'naïve' adaptation, leading to a rapid priming response following infection. Our results provide numerous insights into the importance of both spacer and target sequences for interference and priming, and reveal that priming is a major pathway for adaptation during initial infection.

  8. Interference effects between manual and oral motor skills.

    Science.gov (United States)

    Gagné, Marie-Hélène; Cohen, Henri

    2016-03-01

    Consolidation of a motor skill is characterized by spontaneous improvement in performance between practice sessions. These offline gains can be eliminated if another skill is introduced soon afterward-a phenomenon called retroactive interference. Interference effects have been found in studies using two similar tasks involving the same motor effectors in a manual mode. The present study aimed to determine the extent to which differences in motor production mode modulate interference in skill learning. Healthy participants were assigned to one of three conditions and trained on a finger opposition sequence (FOS) learning task. All subjects were tested 24 h later on the original FOS learning task. Control subjects who were not exposed to a secondary learning task exhibited the expected offline gains after 24 h. Subjects who immediately learned a secondary task after the FOS training, either in the same manual mode (French Sign Language) or in an oral mode (CVC syllables), did not show any offline gains. Interestingly, the amount of interference was equivalent in the manual and oral learning conditions. The results reveal that interference effects in motor skill learning can occur when different effectors are involved in the primary and secondary tasks. The sequence processing abilities of the basal ganglia appear to play a major role in these interference effects.

  9. Cognitive Aware Interference Mitigation Scheme for OFDMA Femtocells

    KAUST Repository

    Alqerm, Ismail

    2015-04-09

    Femto-cells deployment in today’s cellular networks came into practice to fulfill the increasing demand for data services. It also extends the coverage in the indoor areas. However, interference to other femto and macro-cells users remains an unresolved challenge. In this paper, we propose an interference mitigation scheme to control the cross-tier interference caused by femto-cells to the macro users and the co-tier interference among femtocells. Cognitive radio spectrum sensing capability is utilized to determine the non-occupied channels or the ones that cause minimal interference to the macro users. An awareness based channel allocation scheme is developed with the assistance of the graph-coloring algorithm to assign channels to the femto-cells base stations with power optimization, minimal interference, maximum throughput, and maximum spectrum efficiency. In addition, the scheme exploits negotiation capability to match traffic load and QoS with the channel, and to maintain efficient utilization of the available channels.

  10. Interference-aware random beam selection for spectrum sharing systems

    KAUST Repository

    Abdallah, Mohamed M.

    2012-09-01

    Spectrum sharing systems have been introduced to alleviate the problem of spectrum scarcity by allowing secondary unlicensed networks to share the spectrum with primary licensed networks under acceptable interference levels to the primary users. In this paper, we develop interference-aware random beam selection schemes that provide enhanced throughput for the secondary link under the condition that the interference observed at the primary link is within a predetermined acceptable value. For a secondary transmitter equipped with multiple antennas, our schemes select a random beam, among a set of power- optimized orthogonal random beams, that maximizes the capacity of the secondary link while satisfying the interference constraint at the primary receiver for different levels of feedback information describing the interference level at the primary receiver. For the proposed schemes, we develop a statistical analysis for the signal-to-noise and interference ratio (SINR) statistics as well as the capacity of the secondary link. Finally, we present numerical results that study the effect of system parameters including number of beams and the maximum transmission power on the capacity of the secondary link attained using the proposed schemes. © 2012 IEEE.

  11. Moxidectin interference on motor activity of rats

    Directory of Open Access Journals (Sweden)

    Patrícia de Sá e Benevides Rodrigues-Alves

    2009-08-01

    Full Text Available The present study investigated the effects of t moxidectin (MXD in some parameters of rat motor function and neurochemical. The general activity in the open field and the motor coordination in the wooden beam were employed to evaluate the MXD effects. The results showed that, in the open field, even at high doses (2.0 and 20.0 mg/kg, the MXD did not alter the locomotion and the rearing frequencies. However, MXD was able to impair the motor coordination of the animals at wooden beam. Neurochemical studies of striatal GABA and dopamine neurotransmitters showed a reduced levels of dopamine and its metabolite, homovanillic acid, without interference on striatal GABA levels. Since GABAergic receptor stimulation had an inhibitory effect on dopaminergic striatal system, the decreased motor coordination could be attributed to an action of MXD on dopamine system via GABA activation.A moxidectina (MXD é uma droga antiparasitária amplamente empregada em animais domésticos; seu mecanismo de ação, em mamíferos, envolve o neurotransmissor ácido gama-aminobutírico (GABA. Esse neurotransmissor tem papel importante na função motora. Assim, no presente trabalho estudaram-se os efeitos da MXD em alguns parâmetros comportamentais ligados a função motora de ratos e também em sistemas de neurotransmissão central. A atividade geral no campo aberto e a coordenação motora na trave elevada foram empregadas para avaliar os efeitos de diferentes doses de MXD. Os resultados mostraram que: no campo aberto, mesmo as doses maiores (2.0 e 20.0 mg/kg de MXD não alteraram as freqüências de locomoção e levantar. Por outro lado, a MXD foi capaz de prejudicar a coordenação motora dos animais avaliada na trave elevada. Estudos neuroquímicos dos níveis estriatais de GABA e dopamina mostraram redução dos níveis de dopamina e seu metabólito, ácido homavanílico, sem interferência nos níveis de GABA estriatal. Considerando que a estimulação de

  12. Heterogeneous atmospheric chemistry

    Science.gov (United States)

    Schryer, D. R.

    1982-01-01

    The present conference on heterogeneous atmospheric chemistry considers such topics concerning clusters, particles and microparticles as common problems in nucleation and growth, chemical kinetics, and catalysis, chemical reactions with aerosols, electron beam studies of natural and anthropogenic microparticles, and structural studies employing molecular beam techniques, as well as such gas-solid interaction topics as photoassisted reactions, catalyzed photolysis, and heterogeneous catalysis. Also discussed are sulfur dioxide absorption, oxidation, and oxidation inhibition in falling drops, sulfur dioxide/water equilibria, the evidence for heterogeneous catalysis in the atmosphere, the importance of heterogeneous processes to tropospheric chemistry, soot-catalyzed atmospheric reactions, and the concentrations and mechanisms of formation of sulfate in the atmospheric boundary layer.

  13. Students 'Weigh' Atmospheric Pollution.

    Science.gov (United States)

    Caporaloni, Marina

    1998-01-01

    Describes a procedure developed by students that measures the mass concentration of particles in a polluted urban atmosphere. Uses a portable fan and filters of various materials. Compares students' data with official data. (DDR)

  14. Carbon neutron star atmospheres

    CERN Document Server

    Suleimanov, V F; Pavlov, G G; Werner, K

    2013-01-01

    The accuracy of measuring the basic parameters of neutron stars is limited in particular by uncertainties in chemical composition of their atmospheres. For example, atmospheres of thermally - emitting neutron stars in supernova remnants might have exotic chemical compositions, and for one of them, the neutron star in CasA, a pure carbon atmosphere has recently been suggested by Ho & Heinke (2009). To test such a composition for other similar sources, a publicly available detailed grid of carbon model atmosphere spectra is needed. We have computed such a grid using the standard LTE approximation and assuming that the magnetic field does not exceed 10^8 G. The opacities and pressure ionization effects are calculated using the Opacity Project approach. We describe the properties of our models and investigate the impact of the adopted assumptions and approximations on the emergent spectra.

  15. Middle atmospheric electrodynamics

    Science.gov (United States)

    Kelley, M. C.

    1983-01-01

    A review is presented of the advances made during the last few years with respect to the study of the electrodynamics in the earth's middle atmosphere. In a report of the experimental work conducted, attention is given to large middle atmospheric electric fields, the downward coupling of high altitude processes into the middle atmosphere, and upward coupling of tropospheric processes into the middle atmosphere. It is pointed out that new developments in tethered balloons and superpressure balloons should greatly increase the measurement duration of earth-ionospheric potential measurements and of stratospheric electric field measurements in the next few years. Theoretical work considered provides an excellent starting point for study of upward coupling of transient and dc electric fields. Hays and Roble (1979) were the first to construct a model which included orographic features as well as the classical thunderstorm generator.

  16. Global atmospheric changes.

    OpenAIRE

    Piver, W T

    1991-01-01

    Increasing concentrations of CO2 and other greenhouse gases in the atmosphere can be directly related to global warming. In terms of human health, because a major cause of increasing atmospheric concentrations of CO2 is the increased combustion of fossil fuels, global warming also may result in increases in air pollutants, acid deposition, and exposure to ultraviolet (UV) radiation. To understand better the impacts of global warming phenomena on human health, this review emphasizes the proces...

  17. Atmospheric release advisory capability

    International Nuclear Information System (INIS)

    The ARAC system (Atmospheric Release Advisory Capability) is described. The system is a collection of people, computers, computer models, topographic data and meteorological input data that together permits a calculation of, in a quasi-predictive sense, where effluent from an accident will migrate through the atmosphere, where it will be deposited on the ground, and what instantaneous and integrated dose an exposed individual would receive

  18. Atmospheric muons: experimental aspects

    CERN Document Server

    Cecchini, Stefano

    2012-01-01

    We present a review of atmospheric muon flux and energy spectrum measurements over almost six decades of muon momentum. Sea-level and underground/water/ice experiments are considered. Possible sources of systematic errors in the measurements are examinated. The characteristics of underground/water muons (muons in bundle, lateral distribution, energy spectrum) are discussed. The connection between the atmospheric muon and neutrino measurements are also reported.

  19. GREAT/SOFIA atmospheric calibration

    OpenAIRE

    Guan, Xin; Stutzki, Jürgen; Graf, Urs U.; Güsten, Rolf; Okada, Yoko; Torres, Miguel Angel Requena; Simon, Robert; Wiesemeyer, Helmut

    2012-01-01

    The GREAT observations need frequency-selective calibration across the passband for the residual atmospheric opacity at flight altitude. At these altitudes the atmospheric opacity has both narrow and broad spectral features. To determine the atmospheric transmission at high spectral resolution, GREAT compares the observed atmospheric emission with atmospheric model predictions, and therefore depends on the validity of the atmospheric models. We discusse the problems identified in this compari...

  20. The impact of quantum interferences between different J-levels on scattering polarization in spectral lines

    CERN Document Server

    Belluzzi, Luca

    2011-01-01

    The spectral line polarization produced by optically pumped atoms contains a wealth of information on the thermal and magnetic structure of a variety of astrophysical plasmas, including that of the solar atmosphere. A correct decoding of such information from the observed Stokes profiles requires a clear understanding of the effects that radiatively induced quantum interferences (or coherences) between pairs of magnetic sublevels produce on these observables, in the absence and in the presence of magnetic fields of arbitrary strength. Here we present a detailed theoretical investigation on the role of coherences between pairs of sublevels pertaining to different fine-structure J-levels, clarifying when they can be neglected for facilitating the modeling of the linear polarization produced by scattering processes in spectral lines. To this end, we apply the quantum theory of spectral line polarization and calculate the linear polarization patterns of the radiation scattered at 90 degrees by a slab of stellar a...

  1. The quantum interference effects in the Sc II 4247 $\\AA$ line of the Second Solar Spectrum

    CERN Document Server

    Smitha, H N; Stenflo, J O; Bianda, M; Ramelli, R

    2014-01-01

    The Sc II 4247 $\\AA$ line formed in the chromosphere is one of the lines well known, like the Na I D$_2$ and Ba II D$_2$, for its prominent triple peak structure in $Q/I$ and the underlying quantum interference effects governing it. In this paper, we try to study the nature of this triple peak structure using the theory of $F$-state interference including the effects of partial frequency redistribution (PRD) and radiative transfer (RT). We compare our results with the observations taken in a quiet region near the solar limb. In spite of accounting for PRD and RT effects it has not been possible to reproduce the observed triple peak structure in $Q/I$. While the two wing PRD peaks (on either side of central peak) and the near wing continuum can be reproduced, the central peak is completely suppressed by the enhanced depolarization resulting from the hyperfine structure splitting. This suppression remains for all the tested widely different 1D model atmospheres or for any multi-component combinations of them. W...

  2. Derivation of Probability Density Function of Signal-to-Interference-Plus-Noise Ratio for the MS-to-MS Interference Analysis

    Directory of Open Access Journals (Sweden)

    Ho-Kyung Son

    2013-01-01

    Full Text Available This paper provides an analytical derivation of the probability density function of signal-to-interference-plus-noise ratio in the scenario where mobile stations interfere with each other. This analysis considers cochannel interference and adjacent channel interference. This could also remove the need for Monte Carlo simulations when evaluating the interference effect between mobile stations. Numerical verification shows that the analytical result agrees well with a Monte Carlo simulation. Also, we applied analytical methods for evaluating the interference effect between mobile stations using adjacent frequency bands. The analytical derivation of the probability density function can be used to provide the technical criteria for sharing a frequency band.

  3. Atmospheric Laser Communication.

    Science.gov (United States)

    Fischer(, Kenneth W.; Witiw, Michael R.; Baars+, Jeffrey A.; Oke, T. R.

    2004-05-01

    Atmospheric laser communication, often referred to as free-space optics (FSO) or free-space laser (FSL) communication, is similar to fiber optic cable in terms of carrier wavelength and bandwidth capability, but data are transmitted directly through the atmosphere via laser beams over paths from a few meters to 4 km or longer. FSL uses lasers in the near-infrared spectrum, typically at wavelengths of 850 or 1550 nm. Given these wavelengths, atmospheric attenuation must be considered, and an adequate margin of optical power (dB) must exist to support high system availability (the percentage of time that an FSL link is in operation, typically 99.9%). A visual range of 100 m can attenuate a laser beam at a rate of nearly 130 dB km-1. For short links (rain, and snow frequently become issues. To address these issues, long-term climate data are analyzed to determine the frequency of occurrence of low visibilities and low-cloud ceilings. To estimate availability at a site of interest, adjustments to airport climate data are made to accommodate differences in altitude, geography, and the effects of the urban heat island. In sum, communication via FSL is a feasible alternative to fiber optic cable when atmospheric conditions are considered and properly analyzed.(Current affiliation: The Boeing Company, Seattle, Washington+Current affiliation: Department of Atmospheric Sciences, University of Washington, Seattle, Washington

  4. Target-in-the-loop remote sensing of laser beam and atmospheric turbulence characteristics.

    Science.gov (United States)

    Vorontsov, Mikhail A; Lachinova, Svetlana L; Majumdar, Arun K

    2016-07-01

    A new target-in-the-loop (TIL) atmospheric sensing concept for in situ remote measurements of major laser beam characteristics and atmospheric turbulence parameters is proposed and analyzed numerically. The technique is based on utilization of an integral relationship between complex amplitudes of the counterpropagating optical waves known as overlapping integral or interference metric, whose value is preserved along the propagation path. It is shown that the interference metric can be directly measured using the proposed TIL sensing system composed of a single-mode fiber-based optical transceiver and a remotely located retro-target. The measured signal allows retrieval of key beam and atmospheric turbulence characteristics including scintillation index and the path-integrated refractive index structure parameter. PMID:27409206

  5. Target-in-the-loop remote sensing of laser beam and atmospheric turbulence characteristics.

    Science.gov (United States)

    Vorontsov, Mikhail A; Lachinova, Svetlana L; Majumdar, Arun K

    2016-07-01

    A new target-in-the-loop (TIL) atmospheric sensing concept for in situ remote measurements of major laser beam characteristics and atmospheric turbulence parameters is proposed and analyzed numerically. The technique is based on utilization of an integral relationship between complex amplitudes of the counterpropagating optical waves known as overlapping integral or interference metric, whose value is preserved along the propagation path. It is shown that the interference metric can be directly measured using the proposed TIL sensing system composed of a single-mode fiber-based optical transceiver and a remotely located retro-target. The measured signal allows retrieval of key beam and atmospheric turbulence characteristics including scintillation index and the path-integrated refractive index structure parameter.

  6. Resonance elastic scattering and interference effects treatments in subgroup method

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yun Zhao; He, Qing Ming; Cao, Liang Zhi; Wu, Hong Chun; Zu, Tie Jun [School of Nuclear Science and Technology, Xi' an Jiaotong University, Xi' an (China)

    2016-04-15

    Based on the resonance integral (RI) tables produced by the NJOY program, the conventional subgroup method usually ignores both the resonance elastic scattering and the resonance interference effects. In this paper, on one hand, to correct the resonance elastic scattering effect, RI tables are regenerated by using the Monte Carlo code, OpenMC, which employs the Doppler broadening rejection correction method for the resonance elastic scattering. On the other hand, a fast resonance interference factor method is proposed to efficiently handle the resonance interference effect. Encouraging conclusions have been indicated by the numerical results. (1) For a hot full power pressurized water reactor fuel pin-cell, an error of about +200 percent mille could be introduced by neglecting the resonance elastic scattering effect. By contrast, the approach employed in this paper can eliminate the error. (2) The fast resonance interference factor method possesses higher precision and higher efficiency than the conventional Bondarenko iteration method. Correspondingly, if the fast resonance interference factor method proposed in this paper is employed, the k{sub inf} can be improved by ∼100 percent mille with a speedup of about 4.56.

  7. Generalized Interference Alignment—Part II: Application to Wireless Secrecy

    Science.gov (United States)

    Ruan, Liangzhong; Lau, Vincent K. N.; Win, Moe Z.

    2016-05-01

    In contrast to its wired counterpart, wireless communication is highly susceptible to eavesdropping due to the broadcast nature of the wireless propagation medium. Recent works have proposed the use of interference to reduce eavesdropping capabilities in wireless wiretap networks. However, the concurrent effect of interference on both eavesdropping receivers (ERs) and legitimate receivers (LRs) has not been thoroughly investigated, and carefully engineering the network interference is required to harness the full potential of interference for wireless secrecy. This two part paper addresses this issue by proposing a generalized interference alignment (GIA) technique, which jointly designs the transceivers at the legitimate partners to impede the ERs without interfering with LRs. In Part I, we have established a theoretical framework for the GIA technique. In Part II, we will first propose an efficient GIA algorithm that is applicable to large-scale networks and then evaluate the performance of this algorithm in stochastic wireless wiretap network via both analysis and simulation. These results reveal insights into when and how GIA contributes to wireless secrecy.

  8. Memory Interference as a Determinant of Language Comprehension.

    Science.gov (United States)

    Van Dyke, Julie A; Johns, Clinton L

    2012-04-01

    The parameters of the human memory system constrain the operation of language comprehension processes. In the memory literature, both decay and interference have been proposed as causes of forgetting; however, while there is a long history of research establishing the nature of interference effects in memory, the effects of decay are much more poorly supported. Nevertheless, research investigating the limitations of the human sentence processing mechanism typically focus on decay-based explanations, emphasizing the role of capacity, while the role of interference has received comparatively little attention. This paper reviews both accounts of difficulty in language comprehension by drawing direct connections to research in the memory domain. Capacity-based accounts are found to be untenable, diverging substantially from what is known about the operation of the human memory system. In contrast, recent research investigating comprehension difficulty using a retrieval-interference paradigm is shown to be wholly consistent with both behavioral and neuropsychological memory phenomena. The implications of adopting a retrieval-interference approach to investigating individual variation in language comprehension are discussed.

  9. Unraveling cell processes: interference imaging interwoven with data analysis

    DEFF Research Database (Denmark)

    Brazhe, Nadezda; Brazhe, Alexey; Pavlov, A N;

    2006-01-01

    The paper presents results on the application of interference microscopy and wavelet-analysis for cell visualization and studies of cell dynamics. We demonstrate that interference imaging of erythrocytes can reveal reorganization of the cytoskeleton and inhomogenity in the distribution of hemoglo......The paper presents results on the application of interference microscopy and wavelet-analysis for cell visualization and studies of cell dynamics. We demonstrate that interference imaging of erythrocytes can reveal reorganization of the cytoskeleton and inhomogenity in the distribution...... properties differ from cell type to cell type and depend on the cellular compartment. Our results suggest that low frequency variations (0.1-0.6 Hz) result from plasma membrane processes and that higher frequency variations (20-26 Hz) are related to the movement of vesicles. Using double-wavelet analysis, we...... study the modulation of the 1 Hz rhythm in neurons and reveal its changes under depolarization and hyperpolarization of the plasma membrane. We conclude that interference microscopy combined with wavelet analysis is a useful technique for non-invasive cell studies, cell visualization, and investigation...

  10. Interference suppression capabilities of smart cognitive-femto networks (SCFN)

    KAUST Repository

    Shakir, Muhammad

    2013-01-01

    Cognitive Radios are considered a standard part of future heterogeneous mobile network architectures. In this chapter, a two tier heterogeneous network with multiple Radio Access Technologies (RATs) is considered, namely (1) the secondary network, which comprises of Cognitive-Femto BS (CFBS), and (2) the macrocell network, which is considered a primary network. By exploiting the cooperation among the CFBS, the multiple CFBS can be considered a single base station with multiple geographically dispersed antennas, which can reduce the interference levels by directing the main beam toward the desired femtocell mobile user. The resultant network is referred to as Smart Cognitive-Femto Network (SCFN). In order to determine the effectiveness of the proposed smart network, the interference rejection capabilities of the SCFN is studied. It has been shown that the smart network offers significant performance improvements in interference suppression and Signal to Interference Ratio (SIR) and may be considered a promising solution to the interference management problems in future heterogeneous networks. © 2013, IGI Global.

  11. INTERFERENCE FRINGES OF SOLAR ACOUSTIC WAVES AROUND SUNSPOTS

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Dean-Yi; Zhao Hui; Yang, Ming-Hsu; Liang, Zhi-Chao, E-mail: chou@phys.nthu.edu.tw [Physics Department, National Tsing Hua University, Hsinchu, Taiwan (China)

    2012-10-20

    Solar acoustic waves are scattered by a sunspot due to the interaction between the acoustic waves and the sunspot. The sunspot, excited by the incident wave, generates the scattered wave. The scattered wave is added to the incident wave to form the total wave around the sunspot. The interference fringes between the scattered wave and the incident wave are visible in the intensity of the total wave because the coherent time of the incident wave is of the order of a wave period. The strength of the interference fringes anti-correlates with the width of temporal spectra of the incident wave. The separation between neighboring fringes increases with the incident wavelength and the sunspot size. The strength of the fringes increases with the radial order n of the incident wave from n = 0 to n = 2, and then decreases from n = 2 to n = 5. The interference fringes play a role analogous to holograms in optics. This study suggests the feasibility of using the interference fringes to reconstruct the scattered wavefields of the sunspot, although the quality of the reconstructed wavefields is sensitive to the noise and errors in the interference fringes.

  12. Risk of overestimation of urinary cadmium concentrations: interference from molybdenum

    Directory of Open Access Journals (Sweden)

    Cañas A.I.

    2013-04-01

    Full Text Available We show here that the selection of analytical method is critical when measuring low levels of cadmium in human urine. Cadmium is today usually analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS, which has a higher sensitivity than Atomic Absorption Spectroscopy (AAS. ICP-MS cadmium measurements show interference from tin (114Sn and molybdenum oxides, which can result in an overestimation of cadmium levels. The 114Sn interference is stable and can be mathematically corrected. Molybdenum concentrations in urine are variable and different from individual to individual. We have estimated the degree of error which molybdenum interference introduces in the measurement of cadmium in urine by conventional ICP-MS. 268 urine samples from mothers and their children were measured. Removal of the molybdenum oxide interference (DRC-ICP-MS method reduced urinary cadmium concentrations significantly (47.8%. The urinary molybdenum concentration in children was higher than in their mothers, resulting in greater overestimation. Our results clearly show that the DRC method is essential for reliable measurements of urinary cadmium concentrations, particularly in children. Furthermore, care should be taken when comparing Human Biomonitoring data for cadmium in urine and attention should be paid to which analytical method has been used (e.g. AAS and ICP-Ms, and especially if the measurements have been corrected for molybdenum interference.

  13. RNA interference and small interference RNA%RNA干涉和小干涉RNA

    Institute of Scientific and Technical Information of China (English)

    张芹; 王勇; 钱凯先

    2005-01-01

    RNA干涉(RNA interference.RNAi)可以抑制诸多真核基因的表达,小干涉RNA(small intmference RNA,siRNA)是RNA干涉的引发物,不同的siRNA可以引导不同水平的RNA干涉,不同种细胞中siRNA的寡核苷酸链的性质也有很大的不同.非编码RNA中的微小RNA(micnoRNA,miRNA)与siRNA在结构及作用方式等方面有很多区别和联系.RNAi的作用机制大致有两种:在Drosophila中的一般作用模式和在C.elegans中的扩大作用模式.利用RNA干涉技术可以通过抑制基因的表达来研究其功能;RNA干涉作为基因治疗的工具,在肝炎和AIDS的治疗过程中有一定的作用.RNAi的高特异性、高效性、放大效应和无细胞特异性等特点在科研中得到了广泛的应用.

  14. RNA Interference in the Age of CRISPR: Will CRISPR Interfere with RNAi?

    Directory of Open Access Journals (Sweden)

    Unnikrishnan Unniyampurath

    2016-02-01

    Full Text Available The recent emergence of multiple technologies for modifying gene structure has revolutionized mammalian biomedical research and enhanced the promises of gene therapy. Over the past decade, RNA interference (RNAi based technologies widely dominated various research applications involving experimental modulation of gene expression at the post-transcriptional level. Recently, a new gene editing technology, Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR and the CRISPR-associated protein 9 (Cas9 (CRISPR/Cas9 system, has received unprecedented acceptance in the scientific community for a variety of genetic applications. Unlike RNAi, the CRISPR/Cas9 system is bestowed with the ability to introduce heritable precision insertions and deletions in the eukaryotic genome. The combination of popularity and superior capabilities of CRISPR/Cas9 system raises the possibility that this technology may occupy the roles currently served by RNAi and may even make RNAi obsolete. We performed a comparative analysis of the technical aspects and applications of the CRISPR/Cas9 system and RNAi in mammalian systems, with the purpose of charting out a predictive picture on whether the CRISPR/Cas9 system will eclipse the existence and future of RNAi. The conclusion drawn from this analysis is that RNAi will still occupy specific domains of biomedical research and clinical applications, under the current state of development of these technologies. However, further improvements in CRISPR/Cas9 based technology may ultimately enable it to dominate RNAi in the long term.

  15. Atmospheric muons and neutrinos

    CERN Document Server

    Naumov, V A

    2002-01-01

    This paper is a mini-review of the atmospheric muon and neutrino flux calculations based upon a recent version of CORT code and up-to-date data on primary cosmic rays and hadronic interactions. A comparison of calculations with a representative set of atmospheric muon data for momenta below 1 TeV/c is presented. The overall agreement between the calculated muon fluxes and the data provides an evidence in favor of the validity of adopted description of hadronic interactions and shower development. In particular, this supports the low-energy atmospheric neutrino fluxes predicted with CORT which are essentially lower than those used in current analyses of the sub-GeV and multi-GeV neutrino induced events in underground neutrino detectors.

  16. Atmospheres of Brown Dwarfs

    CERN Document Server

    Helling, Christiane

    2014-01-01

    Brown Dwarfs are the coolest class of stellar objects known to date. Our present perception is that Brown Dwarfs follow the principles of star formation, and that Brown Dwarfs share many characteristics with planets. Being the darkest and lowest mass stars known makes Brown Dwarfs also the coolest stars known. This has profound implication for their spectral fingerprints. Brown Dwarfs cover a range of effective temperatures which cause brown dwarfs atmospheres to be a sequence that gradually changes from a M-dwarf-like spectrum into a planet-like spectrum. This further implies that below an effective temperature of < 2800K, clouds form already in atmospheres of objects marking the boundary between M-Dwarfs and brown dwarfs. Recent developments have sparked the interest in plasma processes in such very cool atmospheres: sporadic and quiescent radio emission has been observed in combination with decaying Xray-activity indicators across the fully convective boundary.

  17. Atmospheric Radiative Transfer

    Science.gov (United States)

    Perliski, Lori

    Because radiative transfer cuts across many scientific disciplines with applications including remote sensing, climate, atmospheric chemistry, and photobiology, there is a need for comprehensive books on this subject that can appeal to a wide readership. While Atmospheric Radiative Transfer takes strides toward filling this niche by addressing a broad range of topics, it is dry reading and suffers from lack of detail. The book was based on a graduate-level course taught at the University of Sciences and Technologies in Lille, France, and indeed, the text reads much like an expanded outline perhaps derived from lecture notes.Part one deals with general radiative transfer, and part two covers Earth's radiation budget, the climate system, and remote sensing techniques. The radiative transfer equation and solutions for absorbing and scattering atmospheres are discussed as are the details of absorption, such as energy levels, line strengths, line intensities, equivalent widths, and weak- and strong-line limits.

  18. Observations of Exoplanet Atmospheres

    CERN Document Server

    Crossfield, Ian J M

    2015-01-01

    Detailed characterization of an extrasolar planet's atmosphere provides the best hope for distinguishing the makeup of its outer layers, and the only hope for understanding the interplay between initial composition, chemistry, dynamics & circulation, and disequilibrium processes. In recent years, some areas have seen rapid progress while developments in others have come more slowly and/or have been hotly contested. This article gives an observer's perspective on the current understanding of extrasolar planet atmospheres prior to the considerable advances expected from the next generation of observing facilities. Atmospheric processes of both transiting and directly-imaged planets are discussed, including molecular and atomic abundances, cloud properties, thermal structure, and planetary energy budgets. In the future we can expect a continuing and accelerating stream of new discoveries, which will fuel the ongoing exoplanet revolution for many years to come.

  19. Phenomenology of atmospheric neutrinos

    Directory of Open Access Journals (Sweden)

    Fedynitch Anatoli

    2016-01-01

    Full Text Available The detection of astrophysical neutrinos, certainly a break-through result, introduced new experimental challenges and fundamental questions about acceleration mechanisms of cosmic rays. On one hand IceCube succeeded in finding an unambiguous proof for the existence of a diffuse astrophysical neutrino flux, on the other hand the precise determination of its spectral index and normalization requires a better knowledge about the atmospheric background at hundreds of TeV and PeV energies. Atmospheric neutrinos in this energy range originate mostly from decays of heavy-flavor mesons, which production in the phase space relevant for prompt leptons is uncertain. Current accelerator-based experiments are limited by detector acceptance and not so much by the collision energy. This paper recaps phenomenological aspects of atmospheric leptons and calculation methods, linking recent progress in flux predictions with particle physics at colliders, in particular the Large Hadron Collider.

  20. Atmosphere and Ambient Space

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Atmosphere and Ambient Space This paper explores the relation between atmosphere and ambient space. Atmosphere and ambient space share many salient properties. They are both ontologically indeterminate, constantly varying and formally diffuse and they are both experienced as a subtle, non......-signifying property of a given space. But from a certain point of view, the two concepts also designate quite dissimilar experiences of space. To be ’ambient’ means to surround. Accordingly, ambient space is that space, which surrounds something or somebody. (Gibson 1987: 65) Since space is essentially...... of a surrounding character, all space can thus be described as having a fundamentally ambient character. So what precisely is an ambient space, then? As I will argue in my presentation, ambient space is a sensory effect of spatiality when a space is experienced as being particularly surrounding: a ‘space effect...