[1] The ionospheric responses to the solar eclipse of 15 January 2010 in equatorial anomaly region have been investigated by three vertical-incidence and seven oblique-incidence ionosondes arranged along meridian from geomagnetic latitudes 18°N 30°N eastern China. Though occurred later evening, effect on electron density reflection height F2 layer was clearly observed. study lag (the time between occurrence maximum obscuration depletion foF2) with latitude indicates it increased altitude....

The sporadic E ( Es ) frequently emerging in midlatitude during summer is a very special layer the ionosphere, and its formation mechanism different to from that of other layers. total solar eclipse 22 July 2009 provided unique opportunity study relationship radiation. During day days before after, vertical incidence ionosonde was located Wuhan record ionograms for this event. Two oblique high‐frequency radio systems were used waves Suzhou Huaian. enhancement period observed ionograms....

Nowadays, the terahertz (THz) communication is believed to be a potential solution blackout for reentry vehicles. In this paper, numerical hypersonic fluid model was introduced obtain realistic plasma sheaths. The onboard antenna which installed on wall assumed conformal. transmission of obliquely incident THz waves in sheaths analyzed. According power coefficient decreases with increase speed since both electron density and collision frequency near speed. addition, relation between wave...

Abstract The solar eclipse on 15 January 2010 traversed Asia and completed its travel the Shandong Peninsula in China at sunset. Two vertical incidence ionosondes Wuhan Beijing oblique ionosonde network North were implemented to record ionospheric response eclipse. Following initial electron density decrease caused by eclipse, ionosphere was characterized a strong premidnight enhancement, subsequent decay, ~10 h later postmidnight enhancement. Neither geomagnetic disturbance occurred during...

There have been many studies on the sub-terahertz (sub-THz) wave transmission in reentry plasma sheaths. However, only some of them paid attention to sub-THz waves magnetized In this paper, both unmagnetized and sheaths was investigated. The impacts temporal evolution sheath were studied. “atmospheric window” frequencies a discussed detail. According study, power rates (Tp) for left hand circular (LHC) right modes are obviously higher lower than those sheath, respectively. Tp LHC mode...

In the Internet of Things (IoT), we all are ``things''. Graph theory, a branch discrete mathematics, has been proven to be useful and powerful in understanding complex networks history. By means graph define new concepts terminology, explore definition IoT, then show that IoT is union topological network, data-functional network domi-functional network.

In bioinformatics research field, researchers from biology, and physics, mathematics, computer science other disciplines explore the mystery of genetic language by combination experimental researches theoretical analysis, try reveals essence biological information. Bollobás Riordan pointed out that definition scale-free in context network graph models has never been made precise. We use spanning trees graphs to illustrate some results phenomenon expressing mathematically key notions...

An ionosonde is a kind of high-frequency skywave radar developed for ionospheric research and HF channel management. A novel low-power multifunctional sounding system, i.e., the Wuhan Ionospheric Comprehensive Sounding System (WICSS), presented in this paper. Software-defined-radio-based power low transmitting are two most significant features system. The system can achieve vertical-incidence, oblique backscatter, oblique-incidence within power. application pulse compression coherent...

Vertical-incidence (VI) ionosonde is a kind of high-frequency radar. The sounding waveform an important characteristic for measurement by ionosondes. This letter compares, both theoretically and practically, four different biphase-coded pulse compression radar waveforms which can be employed in the Wuhan Ionosphere Comprehensive Sounding System at VI sounding, including interpulse-coded m sequence, Wolfman-Goutelard intrapulse-coded Barker complementary sequence pairs. experimental results...

Understanding the topological structure of scale-free networks or small world is required and useful for investigation complex networks. We will build up a class edge-growing network models provide an algorithm finding spanning trees in this article.

In this letter, a new high-frequency (HF) skywave multistatic radar that is used for ionospheric sensing and aircraft detection presented. With multiple receiving sites, can detect the in much larger surveillance with high probability obtain characteristics of many paths simultaneously. addition, adopts binary-phase-coded continuous waveform to achieve Doppler resolution, large signal processing gain, low interception. Details system configuration, ambiguity function sounding waveform,...

The dynamical phenomena of complex networks are not easy to model and characterize by current methods mathematics.Newman, Barabási Watts pointed out the direction researching graph theory, which was successfully applied in investigation networks, Newman's network-based have been a variety fields.Some well-known new mathematics provided this article, associated with construction problems on scale-free models from real networks.

Electromagnetically induced transparency (EIT) in quantum dot exciton systems which the behaves as a two-level system is investigated theoretically. It shown that due to strong exciton–phonon coupling EIT can occur such and ultraslow light propagate. The nonlinear optical absorption Kerr coefficient based on are also calculated. numerical results show giant effects be obtained while frequency of signal field differs only by an amount LO phonon from systems.

Monostatic radar, whether using interpulse or intrapulse coded pulse trains, will suffer from the blind zones caused by eclipsing. This letter proposes a novel biphase radar waveform diverse Pulse Repetition Intervals (PRIs) instead of consistent PRI within each coherent processing interval (CPI). can achieve long unambiguous range, high-range resolution and high Doppler without zones, is specially suitable for monostatic ionosonde.

Vertical ionograms suffer from artifacts and distortion due to other users of the high-frequency channel ionosphere. The traces each layer have variable shapes, so automatic scaling vertical is rather complicated. New algorithms for signal identification trace extraction are developed support scaling. Different features signals, such as signal-to-noise ratio, Doppler shift, virtual height, converted certainty factors combined identify signals. Kalman filtering, which widely used in...

Incoherent scatter radar (ISR) is the only ground-based instrument that can detect space plasma parameters from tens to thousands of kilometers above earth. The Prototype Scatter Radar System Nanchang University, a versatile detection radar, will be built at University ionosphere over China in end 2013. Software-defined radio (SDR)-based and active phased antenna array are two most significant features this system. It probe real time altitude range (80-400 km) according simulation. novel ISR...

Based on typical scale-free network models, we set up the partial differential equation satisfied more general dynamic systems, and then not only find another important topological property of networks, but also discuss real background meaning every function in dynamical systems.Meanwhile generalize BA-network-model growth way ("star-graph-growth-way"). Starting from a situation, establish model containing "star-graph-growth-way" "triangle-growth-way".By analysis, this is small-wall.Finally,...

Ionospheric sounding is a technique that provides real-time data on high-frequency ionospheric-dependent radio propagation. This letter presents Universal Software Radio Peripheral-based ionospheric radar, which relies basic system consisting of synchronized transmitter and receiver. The radar has the advantages miniaturization, modularization, low power, cost. three most significant features are it software-defined universal platform-based transmitting power. novel vertical-incidence can...

Abstract Incoherent scatter radars have become an important means of ionospheric detection, which is the only ground instrument that can detect plasma parameters over entire ionosphere (60–2,000 km). In Sanya China, advanced high‐power phased array incoherent radar under construction. The has advantages continuous observation, full space coverage, and rapid scanning. Usually, since plasma‐scattered signal weak, estimation signal‐to‐noise ratio (SNR) relative error significant for detection...

Abstract Ionospheric incoherent scatter radar (ISR), which is used to detect ionospheric electrons and ions, generally, has megawatt class transmission power hundred meter level antenna aperture. The crucial purpose of this detecting technology get parameters by acquiring the autocorrelation function spectrum target plasma echoes. Whereas ISR's echoes are very weak because small cross section its target, estimating ability will be significantly instructive meaningful for ISR system design....

Multiple-partite networks exist in the real world, such as engineering constructions consisted of workers and machines. We build up random multiple-partite network models show their topological properties by means well-known methods appeared Barabási-Albert model. find some new characters model BA-type models, a connection between degree distribution P(k) cumulative P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">cum</sub> (k), discuss...

Many real life networks present diameter logarithmic with the number of nodes and degree distribution that follow power law. Often these have also a modular self-similar feature usually associated topological restrictions-their clustering is low, even zero, they are almost non-planar. In paper, we propose generalized self-similarity growing network model. As construction deterministic, can capture exact analytic expressions for relevant properties model including average degree, coefficient,...