Predicting microseismic,acoustic emission and electromagnetic radiation data using neural networks

Microseism,acoustic emission and electromagnetic radiation(M-A-E)data are usually used for predicting rockburst hazards.However,it is a great challenge to realize the prediction of M-A-E data.In this study,with the aid of a deep learning algorithm,a new method for the prediction of M-A-E data is proposed.In this method,an M-A-E data prediction model is built based on a variety of neural networks after analyzing numerous M-A-E data,and then the M-A-E data can be predicted.The predicted results are highly correlated with the real data collected in the field.Through field verification,the deep learning-based prediction method of M-A-E data provides quantitative prediction data for rockburst monitoring.

Imaging assessment of photosensitizer emission induced by radionuclide-derived Cherenkov radiation using charge-coupled device optical imaging and long-pass filters

BACKGROUND Radionuclides produce Cherenkov radiation(CR),which can potentially activate photosensitizers(PSs)in phototherapy.Several groups have studied Cherenkov energy transfer to PSs using optical imaging;however,cost-effectively identifying whether PSs are excited by radionuclide-derived CR and detecting fluorescence emission from excited PSs remain a challenge.Many laboratories face the need for expensive dedicated equipment.AIM To cost-effectively confirm whether PSs are excited by radionuclide-derived CR and distinguish fluorescence emission from excited PSs.METHODS The absorbance and fluorescence spectra of PSs were measured using a microplate reader and fluorescence spectrometer to examine the photo-physical properties of PSs.To mitigate the need for expensive dedicated equipment and achieve the aim of the study,we developed a method that utilizes a chargecoupled device optical imaging system and appropriate long-pass filters of different wavelengths(manual sequential application of long-pass filters of 515,580,645,700,750,and 800 nm).Tetrakis(4-carboxyphenyl)porphyrin(TCPP)was utilized as a model PS.Different doses of copper-64(^(64)CuCl_(2))(4,2,and 1 mCi)were used as CR-producing radionuclides.Imaging and data acquisition were performed 0.5 h after sample preparation.Differential image analysis was conducted by using ImageJ software(National Institutes of Health)to visually evaluate TCPP fluorescence.RESULTS The maximum absorbance of TCPP was at 390-430 nm,and the emission peak was at 670 nm.The CR and CRinduced TCPP emissions were observed using the optical imaging system and the high-transmittance long-pass filters described above.The emission spectra of TCPP with a peak in the 645-700 nm window were obtained by calculation and subtraction based on the serial signal intensity(total flux)difference between^(64)CuCl_(2)+TCPP and^(64)CuCl_(2).Moreover,the differential fluorescence images of TCPP were obtained by subtracting the^(64)CuCl_(2)image from the^(64)CuCl_(2)+TCPP image.The experimental results considering different^(64)CuCl_(2)doses showed a dosedependent trend.These results demonstrate that a bioluminescence imaging device coupled with different longpass filters and subtraction image processing can confirm the emission spectra and differential fluorescence images of CR-induced TCPP.CONCLUSION This simple method identifies the PS fluorescence emission generated by radionuclide-derived CR and can contribute to accelerating the development of Cherenkov energy transfer imaging and the discovery of new PSs.

Unified Analysis for Calculating the Incoherent Spontaneous Emission of Cooperative Radiations

A unified analysis is presented to calculate the incoherent spontaneous power of cooperative radiations based on self-amplified spontaneous emission. Using quantum mechanical tools, we derive analytical expressions for the incoherent spontaneous power of undulator and Cherenkov free-electron lasers （FELs）. The undulator and Cherenkov FELs are considered as two different examples for the radiation that accumulate cooperatively. In the case of the undulator FEL, we show an excellent agreement between an expression for the incoherent radiation power derived in the present work and that obtained using a completely different approach [Phys. Ftev. E 65 （2002） 026501]. For the Cherenkov radiation, we demonstrate a satisfactory agreement between the incoherent power predicted in our analysis and previous experimental results.

Variation of Radiation Emission with Argon Gas Pressure in UM Plasma Focus with the Hollow Anode

A Plasma Focus device (2.2 kJ, 12 kV) is studied as a pulsed X-ray source, operated with Argon at a filling pressure in the range of 0.7 to 2.5 mbar. The time resolved X-ray signals are measured with an array of PIN diode detectors. The X-ray emission produced by the plasma focus discharge at various pressures is investigated and compared. It is found that at the high pressure regime of more than 1.5 mbar, very consistent and high output of X-ray radiation is obtained, at the peak of the discharge current. A remarkable increase of about five times of the average X-ray yield is achieved at optimum pressure 1.7 mbar compared to that obtained at other pressures. An indirect method to determine the electron temperature of the plasma is achieved by using the array of 5 channel PIN diode detector coupled with Al foil of different thicknesses. The result shows that the electron temperature of the plasma is 7 keV, when the operating pressure is at 1.7 mbar. The maximum total X-ray yield is about 2.53 mJ per shot at optimum pressure, equivalent to the efficiency of 0.00012%.

Dual Anthropogenic Origin of Global Warming through GHGs and IR Radiation Emissions from Artificialized Soils

This paper contributes to explain the global warming instead of"giving up"and thinking about passively adapting to climate change or global warming.It makes more sense to tackle what creates the greenhouse effect and contributes to global warming.The greenhouse effect is not only due to GHGs emissions,but also to the excess IR radiation emitted during the day,by artificial surfaces,following the absorption of solar radiation.The phenomenon should be compared to that of radiative forcing well known by climatologists and which makes the link between atmospheric pollution and the density of heat fluxes stopped by the atmosphere inducing global warming.It becomes clear that type an equation here.The surplus CO2 and IR radiation emissions influence global warming,not to mention the direct part of the heat released by the combustion of fossil fuels and even renewable(wood fires,biogas,friction of wind turbine propellers with the air).

A Novel Trident Incurvature Shape DGS to Suppress Radiated Emission in High Speed Printed Circuit Board

As per the entail in wireless communication, the ever increasing switching speeds of digital devices pose significant challenges. Signal quality is more important for high speed products and the signal integrity must ensure reliable transmission where signal integrity is a measure of the quality of an electrical signal. A high speed differential signal will result in signal integrity issues such as crosstalk and radiated emission. One of the solutions to suppress radiated emission is defected ground pattern. This paper introduces a novel trident incurvature shaped defected ground structure to suppress radiated emission that arises in high speed differential signal. The proposed defected ground structure is implemented using Ansoft HFSS simulation tool and its performance is quantified in terms of scattering parameters. The proposed trident incurvature shaped defected ground pattern reduces near end coupling and far end coupling by more than 6 dB and 2 dB respectively. It also provides better return loss and insertion loss in the frequency range 1 - 6 GHz.

Analysis and Solution for Excessive Radiated Emission with a Certain Type of Laser Scanner

The problem of excessive radiated emission for a certain type of laser scanner is discussed in this paper.Firstly,the frequency characteristics of the laser scanner can be obtained by traditional test methods.According to the frequency and electronic equipment characteristics,the interference source can be estimated and established.Then based upon analysis,modified methods are proposed.By applying the above methods,the interference source can be identified and the amount of radiated emission from the scanner can be reduced effectively.Finally,the scanner can op erate in a compatible manner with other electronic systems at the same time.The above methods can provide a reference for electronic equipment design ensuring electromagnetic compatibility and passing the radiated emission test.

How can FAST improve study of the pulsar emission mechanism and magnetospheric dynamics?

The Five-hundred-meter Aperture Spherical radio Telescope(FAST) has the potential to discover many new pulsars and new phenomena. In this paper we mainly concentrate on how FAST can impact study of the pulsar emission mechanism and magnetospheric dynamics. Several observational programs heading to this direction are reviewed. To make full use of the superior performance of FAST and maximize the scientific outcome, these programs can be arranged in different phases of FAST according to their demands for observational conditions. We suggest that programs can be performed following the test phase, which are observations of multifrequency mean pulse profiles, anomalous X-ray pulsars(AXPs)/soft gamma-ray repeaters(SGRs), mode changing, drifting subpulse and nulling. The long-term monitoring can be carried out for mode changing, AXPs/SGRs and precessional pulsars. Others programs, including polarization observations of radio and γ-ray pulsars, searching for weak pulse components, and multifrequency observations of subpulse drifting, microstructure and giant pulses, can be conducted in all the normal operating phases(the first and second phases). These programs will push forward the frontier in this field in different respects. The search for sub-millisecond pulsars and follow-up observations of their emission properties are very important projects for FAST, but they may be covered by other papers in this mini-volume; therefore,they are not discussed here.

Experimental study of ultralong wave band for electro－magnetic signals and acoustic emission during rock fracture

The electro-magnetic (EM) and acoustic emission (AE) in the fracture process of both dry and wet rock samples including gabbro, granite, sandstone and marble are studied in the experiment in the laboratory under uniaxial pressure. Signals during the test are detected in ultralow frequency band. The experimental results may be outlined as follows: original waveforms of the electro-magnetic radiation (EMR) and AE in the range of 0-20 kHz frequencies are obtained; the EMR's intensity in fracture process is related to some factors as rock type, content of water, fracture intensity of rocks, loading rates and fracture state etc.; the EMR'S rate is proportional to that of AE during fracture statistically. About 70% of maximum values of EMR rate and AE rate are corresponded with each other; furthermore, the EM signals (EMS) are generally more developed and longer duration than AE signals; the principal energy of EMS detected by copper coin antenna as sensor in power spectra are distributed in frequencies lower than 6 kHz and otherwise those detected by EMinduction coil are at about 10 kHz, and in contrast the major energies of AE are in frequencies less than3 kHz; another notable phenomenon is that distinct electro-magnetic signals are detected before AE occurrence. Since EMR and AE signals obtained in the process of rock fracture are better corresponded to eachother, therefore it'S reasonable to propose that the EMR anormalies observed prior to some earthquakes aremainly produced by fractures of rock in source region, as for the EMS occurred before AE may be related topiezoelectric and piezomagnetic effects.

Damage evolution law of coal-rock under uniaxial compression based on the electromagnetic radiation characteristics

Based on electromagnetic radiation characteristics, the present research studied the damage evolution of rock under uniaxial compression. Besides, this research built the coal-rock damage evolution model considered residual strength. The applicability and accuracy of the model were verified through experiments. The results show that coal-rock damage evolution consists of four periods. The first period is from the beginning of compression to nearly 20% of the stress peak value, during which the damage variable changes stably about 0.1, and accordingly a few of electromagnetic radiation signals emerge. The second period is from about 20% to 70% of the stress peak value. The damage has stable development, and the parameter of electromagnetic radiation characteristics turns larger continuously with the increase of stress. The third period is when the damage has accelerated development, the coal-rock was broken which result from sharp increasing of the damage variable, meanwhile a great quantity of electromagnetic radiation signals emerge. The fourth period is after the coal-rock fracture, during which the damage variable corresponding to the parameter of electromagnetic radiation characteristics has a stable development. This research has great academic and realistic significance for further studies the electromagnetic radiation characteristics of coal-rock under loading and damage and the forecasting of coal-rock dynamic disasters.

Application of fluorodeoxyglucose positron emission tomography in the management of head and neck cancers

The use of fluorodeoxyglucose positron emission to-mography(FDG PET) scan technology in the manage-ment of head and neck cancers continues to increase. We discuss the biology of FDG uptake in malignant lesions and also discuss the physics of PET imaging. The various parameters described to quantify FDG up-take in cancers including standardized uptake value, metabolic tumor volume and total lesion glycolysis are presented. PET scans have found a significant role in the diagnosis and staging of head and neck cancers. They are also being increasingly used in radiation ther-apy treatment planning. Many groups have also used PET derived values to serve as prognostic indicators of outcomes including loco-regional control and overall survival. FDG PET scans are also proving very useful in assessing the efficacy of treatment and management and follow-up of head and neck cancer patients. This review article focuses on the role of FDG-PET com-puted tomography scans in these areas for squamous cell carcinoma of the head and neck. We present the current state of the art and speculate on the future applications of this technology including protocol de-velopment, newer imaging methods such as combinedmagnetic resonance and PET imaging and novel ra-diopharmaceuticals that can be used to further study tumor biology.

Thermal radiation properties of PTFE plasma

To illuminate the thermal transfer mechanism of devices adopting polytetrafluoroethylene（PTFE） as ablation materials,the thermal radiation properties of PTFE plasma are calculated and discussed based on local thermodynamic equilibrium（LTE） and optical thin assumptions.It is clarified that line radiation is the dominant mechanism of PTFE plasma.The emission coefficient shows an opposite trend for both wavelength regions divided by 550 nm at a temperature above15 000 K.The emission coefficient increases with increasing temperature and pressure.Furthermore,it has a good log linear relation with pressure.Equivalent emissivity varies complexly with temperature,and has a critical point between 20 000 K to 25 000 K.The equivalent cross points of the average ionic valence and radiation property are about 10 000 K and 15 000 K for fully single ionization.

Protective Performance of Woven Fabrics against Heat Radiation

In this paper,the protective performance of woven fab-rics against heat radiation is studied from the view offabric structure.As indices reflecting the protective per-formance against heat radiation,the heat emissivity andthe transmissivity of different fabrics are measured.It ispointed out that structure changes of common textiles af-fect their transmission to heat radiation while have littleinfluence on their absorption or reflection to heat radi-ation except fabrics surfaces are aluminized.Double-layer weave is proved to be an effective fabric weave forreducing the trasmissivity.It helps increase the densityand tightness while keeps the comfort of woven fabrics atthe same time.

Preparation and cooling performance analysis of double-layer radiative cooling hybrid coatings with TiO_(2)/SiO_(2)/Si_(3)N_(4) micron particles

Passive daytime radiative cooling is achieved by radiating heat into outer space through electromagnetic waves without energy consumption. A scalable double-layer coating with a mixture of TiO_(2), SiO_(2), and Si_(3)N_(4)micron particles for radiative cooling is proposed in this study. The finite-difference time-domain algorithm is used to analyze the influence of particle size and coating thickness on radiative cooling performance. The results of the simulation show that the particle size of 3 μm can give the best cooling performance, and the coating thickness should be above 25 μm for SiO_(2)coating. Meanwhile, the mixture of SiO_(2)and Si_(3)N_(4)significantly improves the overall emissivity. Through sample preparation and characterization,the mixture coating with a 1:1 ratio addition on an Al substrate exhibits high reflectivity with a value of 87.6% in the solar spectrum, and an average emissivity of 92% in the infrared region(2.5 μm–15 μm), which can be attributed to the synergy among the optical properties of the material. Both coatings can theoretically be cooled by about 8℃ during the day and about 21℃ at nighttime with hc = 4 W·m^(-2)·K^(-1). Furthermore, even considering the significant conduction and convection exchanges, the cooling effect persists. Outdoor experimental results show that the temperature of the double-layer radiative cooling coating is always lower than the ambient temperature under direct sunlight during the day, and can be cooled by about 5℃ on average, while lower than the temperature of the aluminum film by almost 12℃.

Flare evolution and polarization changes in fine structures of solar radio emission in the 2013 April 11 event

The measurement of positions and sizes of radio sources in observations is important for un- derstanding of the flare evolution. For the first time, solar radio spectral fine structures in an M6.5 flare that occurred on 2013 April 11 were observed simultaneously by several radio instruments at four different observatories： Chinese Solar Broadband Radio Spectrometer at Huairou （SBRS/Huairou）, Ondrejov Radio Spectrograph in the Czech Republic （ORSC/Ondrejov）, Badary Broadband Microwave Spectropolarimeter （BMS/Irkutsk）, and spectrograph/IZMIRAN （Moscow, Troitsk）. The fine structures included microwave zebra patterns （ZPs）, fast pulsations and fiber bursts. They were observed during the flare brightening lo- cated at the tops of a loop arcade as shown in images taken by the extreme ultraviolet （EUV） telescope onboard NASA＇s satellite Solar Dynamics Observatory （SDO）. The flare occurred at 06：58-07：26 UT in solar active region NOAA 11719 located close to the solar disk center. ZPs appeared near high frequency boundaries of the pulsations, and their spectra observed in Huairou and Ondrejov agreed with each other in terms of details. At the beginning of the flare＇s impulsive phase, a strong narrowband ZP burst occurred with a moderate left-handed circular polarization. Then a series of pulsations and ZPs were observed in almost unpolarized emission. After 07：00 UT a ZP appeared with a moderate right-handed polarization. In the flare decay phase （at about 07：25 UT）, ZPs and fiber bursts become strongly right-hand polarized. BMS/Irkutsk spectral observations indicated that the background emission showed a left-handed circular polarization （similar to SBRS/Huairou spectra around 3 GHz）. However, the fine structure appeared in the right-handed polarization. The dynamics of the polarization was associated with the motion of the flare ex- citer, which was observed in EUV images at 171 A and 131 A by the SDO Atmospheric Imaging Assembly （AIA）. Combining magnetograms observed by the SDO Helioseismic and Magnetic Imager （HMI） with the homologous assumption of EUV flare brightenings and ZP bursts, we deduced that the observed ZPs correspond to the ordinary radio emission mode. However, future analysis needs to verify the assumption that zebra radio sources are really related to a closed magnetic loop, and are located at lower heights in the solar atmosphere than the source of pulsations.

Investigation of Acoustic Emission Caused by Filtration of an Air Flow through a Porous Medium

We study characteristics of acoustic emission caused by an air flow filtered through samples of solid porous pumice either partially filled with glycerin or dry. Some peculiarities of the laboratory setup and the performed experiments are described. Samples of different porosity and several values of the air pressure drop are tested. Physical reasons for the difference in acoustical emission spectra of samples of different porosity and in the relaxation times of the acoustic emission level caused by different porosity and fluid saturation are discussed. It is proposed to use the phenomenon of acoustic emission for detecting the fluid trapped in the pores of cores. The existing results based on the borehole field experiments are rough. The frequency range of signals recorded in these experiments is less than 5 kHz (up to 10 kHz). It is shown by our laboratory measurements that the required frequency band should be up to 50 - 60 kHz to reflect the features of the spectral composition of the acoustic emission in predicting the fluid content. The level of acoustic noise under field conditions is much higher, i.e., by 10 - 15 dB, than the noise achieved under laboratory conditions. Since the sensitivity of the recorders and the frequency range are considerably higher in our experiments, they are unique when applied to the solved problem.

Stimulated Emission of Gamma Photon from Ultrashort Pulse Intense Laser—Solid—Target Interaction

The efficient production of energetic γ photons is a significant physical process in the relativistic ultrashortpulse laser-plasma inducing photonuclear action. Based on the interaction of laser-solid-target, an analytical theory onstimulated γ photon emission from a hot electron firing the target-nucleus is developed by a relativistic full quantummethod. The emitting power or probability of γ photon in arbitrary space direction can be calculated for laser irradiatingsolid-target normally. It is valid only if the scatter-centre is immovable or its motion can be neglected compared withthat of the scattered electrons.

Radiation Absorption Mechanism in Nonvolatile MNOS Structure

The γ-ray radiation will speed up the discharge of the storedcharge in nonvolatile MNOS structure. The radiation absorptionmechanism to enhance the discharge is discussed. A direct radiationemission model from the interface traps distributing both in energylevel and in space is given. The theoretical results based on thismodel are in good agreement with experimental measurements.

Is Gravitational Radiation a Radiation of the Same Level as Electromagnetic Radiation?

The notion of gravitational radiation as a radiation of the same level as the electromagnetic radiation is based on the theoretically proven and experimentally confirmed facts of the existence of stationary states of an electron in its gravitational field, characterized by the gravitational constant K = 1042 G (G is Newtonian gravitational constant) and unrecoverable space-time curvature Λ. These experimental facts include, in particular, data on the broadening of the spectra of the characteristic radiation of multielectron atoms. This broadening of the spectra can be only due to the additional broadening mechanism, in particular the presence of excited states of electrons in their gravitational field. Another fact is the new line in the X-ray emission spectrum according to the results of observation with MOS-camera of the XMM-Newton observatory. This line unlike other identified lines of electromagnetic radiation cannot be assigned to any atomic transition.

The definition analyses of radiation temperature measurement area

In the research of primary spectrum pyrometry, this paper discussed the definition problem of radiation temperature measurement area based on the measurement coordinates. For the linear spectrum emissivity model and improved monotonic spectrum emissivity model, the characteristics of radiation temperature measurement area restricted by the measurement coordinates were theoretically analyzed, through the investigations of the temperature and emissivity coordinate axes. Choosing the specific primary spectrum pyrometer as an example in applications, the theoretical area of radiation temperature measurement of this pyrometer was given and it was verified through blackbody experiments. The discussions of this paper will provide the necessary foundation for the theory research development of primary spectrum pyrometry and the realization of technical applications.