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Facile Preparation of Micrometer KClO4/Zr Energetic Composite Particles with Enhanced Light Radiation
摘要： Developing energetic composite materials consisting of fuel and oxidizer is an effective strategy to enhance the energy release property. However, this strategy has rarely been applied in Potassium Perchlorate (KClO4)-containing energetic materials, even though KClO4 is a much stronger oxidizer than most previously reported metal-oxide oxidizer. One of the main obstacles is the lack of simple and in situ ways to introduce KClO4 into the composite. In present work, micrometer KClO4/Zirconium (KClO4/Zr) composite particles were successfully prepared using a facile chemical solution-deposition method. The structure and particle morphologies of as-obtained KClO4/Zr composite were characterized by X-ray diffraction (XRD) and scanning electronic microscope (SEM)-EDS (Energy Dispersive Spectrometer). The evolutionary combustion behavior was evaluated using flame-based light-radiation spectra and successive photography technique. Results showed that the morphology, light-radiation properties and flame-evolution characteristics of KClO4/Zr composite varied with the content of KClO4 and the particle size of Zr. Compared with the mechanical mixture of KClO4/Zr, the KClO4/Zr composite showed much higher light-radiation intensity and longer light-emission duration time after reasonably controlling the preparation parameters. Flame photographs revealed that the enhanced light radiation of KClO4/Zr composite should be ascribed to higher use efficiency of “oxygen” in the oxidizer, which promoted both the solid–solid and solid–gas reaction pathways between KClO4 and Zr.
关键词： Potassium Perchlorate/Zirconium (KClO4/Zr) composite,frame photographs,reaction pathways,light radiation
更新于2025-09-23 15:22:29
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The Spectral Content of <i>SDO</i> /AIA 1600 and 1700 ? Filters from Flare and Plage Observations
摘要： The strong enhancement of the ultraviolet emission during solar flares is usually taken as an indication of plasma heating in the lower solar atmosphere caused by the deposition of the energy released during these events. Images taken with broadband ultraviolet filters by the Transition Region and Coronal Explorer and Atmospheric Imaging Assembly (AIA; 1600 and 1700 ?) have revealed the morphology and evolution of flare ribbons in great detail. However, the spectral content of these images is still largely unknown. Without knowledge of the spectral contribution to these UV filters, the use of these rich imaging data sets is severely limited. Aiming to solve this issue, we estimate the spectral contributions of the AIA UV flare and plage images using high-resolution spectra in the range 1300–1900 ? from the Skylab NRL SO82B spectrograph. We find that the flare excess emission in AIA 1600 ? is dominated by the C IV 1550 ? doublet (26%), Si I continua (20%), with smaller contributions from many other chromospheric lines such as C I 1561 and 1656 ? multiplets, He II 1640 ?, and Si II 1526 and 1533 ?. For the AIA 1700 ? band, the C I 1656 ? multiplet is the main contributor (38%), followed by He II 1640 (17%), and accompanied by a multitude of other, weaker chromospheric lines, with minimal contribution from the continuum. Our results can be generalized to state that the AIA UV flare excess emission is of chromospheric origin, while plage emission is dominated by photospheric continuum emission in both channels.
关键词： Sun: UV radiation,Sun: flares,Sun: atmosphere,Sun: chromosphere,Sun: photosphere
更新于2025-09-23 15:22:29
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Real-time retrieval of transient heat flux on the surface of participating medium by using the EKF-RLSE technique
摘要： A hybrid algorithm of extended Kalman filtering and recursive least-square estimator (EKF-RLSE) is developed to solve the nonlinear inverse heat conduction-radiation problems in participating medium. By measuring the time-resolved temperature signals from a thermocouple installed on the other boundary of the participating medium, the proposed EKF-RLSE algorithm can realize real-time retrieval of the time-varying heat flux on the medium surface. The influence factors of the sampling interval, measurement and process covariance, forgetting factor, and medium thickness on the reconstruction accuracy and stability of the EKF-RLSE are investigated by numerical experiments. All the estimated results show that the present algorithm is robust and accurate in real-time estimating transient heat flux. If the nonlinear coupled conduction and radiation heat transfer problems is regard as the linear problems, the unknown time-dependent heat flux predicted by the KF-RLSE are also illustrated in this work.
关键词： Participating medium,Kalman filtering,Inverse nonlinear conduction-radiation,Time-varying heat flux,Recursive least squares estimator
更新于2025-09-23 15:22:29
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ICRU report?91 on prescribing, recording, and reporting of stereotactic treatments with small photon beams; ICRU-Bericht 91 über die Verschreibung, Aufzeichnung und Dokumentation von stereotaktischen Behandlungen mit kleinen Photonenfeldern;
摘要： The International Commission on Radiation Units and Measurements (ICRU) report 91 with the title “prescribing, recording, and reporting of stereotactic treatments with small photon beams” was published in 2017. This extensive publication covers different relevant aspects of stereotactic radiotherapy such as small field dosimetry, accuracy requirements for volume definition and planning algorithms, and the precise application of treatment by means of image guidance. Finally, recommendations for prescribing, recording and reporting are given.
关键词： Organs at risk,Stereotactic radiotherapy,Radiotherapy planning, computer-assisted,Stereotactic body radiation therapy,Stereotactic radiosurgery
更新于2025-09-23 15:22:29
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[IEEE 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Vladivostok, Russia (2018.10.3-2018.10.4)] 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - The Increase of the Effectiveness of the Autonomous System of Solar Energy Supply
摘要： For the effective heat supply of the consumers the solar energy is viewed with the aim of replacing the organic fuel the costs on which constantly increase. The analysis of the existing solar collectors as the basic element of the system of solar heat supply and its factors for the increase of the effectiveness of its usage is shown. The interconnection of constructive and regime parameters of solar collectors and the necessity of the regulating the regime of their work for the effectiveness of the system of solar heat supply as a whole are also shown. To achieve the formulated purpose the regulating of the scheme of the connection of solar collectors between them is offered and as the source of power supply the solar battery is suggested for providing the autonomy of the system of solar heat supply. The principle of the control of the scheme of the connecting of solar collectors and the description of the regime of work of the suggested device are examined. The block scheme of the algorithm of control for providing the given parameters of regulating is worked out and shown.
关键词： system of solar heat supply,parameters of solar collector,algorithm of control,scheme of the connection of the collectors,solar collector,solar battery,solar radiation
更新于2025-09-23 15:22:29
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[IEEE 2018 20th International Symposium on High-Current Electronics (ISHCE) - Tomsk, Russia (2018.9.16-2018.9.22)] 2018 20th International Symposium on High-Current Electronics (ISHCE) - Cherenkov Ka-Band Oscillator with 45% Efficiency of Beam-to-Microwave Power Conversion
摘要： The paper describes a study of a new relativistic microwave Cherenkov generator of millimeter wavelength range with the transverse dimension of the electrodynamic system D>2.5λ, where D is the average diameter of the slow wave structure, and λ is the radiation wavelength. The investigations were carried out with a high-current SINUS-200 electron accelerator at a voltage of 473 kV and an electron beam current of 3.8 kA. The use of several, complementing each other, mechanisms of suppression of parasitic waves provides stable microwave generation at a specified frequency of 36.4 GHz. The microwave power in the experiment 804 MW with 45% beam-to microwave power conversion.
关键词： amplitude modulation of high-current electron beam,slow wave structures,Cherenkov radiation,electromagnetic radiation
更新于2025-09-23 15:21:21
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Asymmetric Half-Bowtie Antennas with Tilted Beam Patterns
摘要： A novel geometrical change is introduced to a broadband bowtie antenna to allow radiation beam tilting without the use of an engineered material. By halving the bowtie arms along their horizontal axis of symmetry and judicially removing parts of it, the phase line of the antenna can be controlled to achieve various magnitudes of tilted radiation patterns. Further bandwidth improvements are realized when the traditional triangular antenna is replaced with an elliptical equivalent. Using either geometry, the amount of tilt in free space across its bandwidth could vary from 0° to 48°. For the printed case, a unidirectional antenna pattern is tilted to approximately 40° along the useable bandwidth of 32% with a peak gain of about 5 dBi and a front to back ratio greater than 10 dB. A prototype antenna is fabricated and tested. The measured results satisfactorily validate the numerical ones.
关键词： tilted radiation beams,antenna radiation patterns,Bowtie antennas
更新于2025-09-23 15:21:21
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Imaging Considerations in Pregnancy
摘要： Pregnancy is a complex interplay of multiple physiologic states maintaining balance between the needs of mother and fetus. This is reflected in hormonal, hemodynamic, hematologic, and immunologic changes at both global and cellular levels. A decrease in brain size and increase in heart, pituitary, thyroid, and kidney sizes secondary to hormonal influences have been observed during pregnancy.1,2 Circulating hormones also have trophic effect on preexisting neoplasms, such as meningioma, pituitary adenomas, and breast carcinoma.3 The increased blood volume and clotting factor alterations increase the risk of stroke, especially during the peripartum and postpartum period.4,5 Hemodynamic and hormonal effects on vessel wall integrity can lead to worsening of aneurysm with possible hemorrhage, whereas prolonged labor may increase risk of infarct from venous thrombosis or dissection.6,7 In contrast, increased cortisol levels have shown to improve autoimmune diseases such as multiple sclerosis by exerting inhibitory effect on T-cell function8–10
关键词： Radiation safety,Pregnancy,Imaging,RCVS,Stroke,PRES,Eclampsia
更新于2025-09-23 15:21:21
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New Optical Properties of Ice Crystals for Multi-Class Cloud Microphysics
摘要： New optical properties of ice crystals were implemented in a general circulation model (GCM). Ebert and Curry’s (1992) and Fu’s (1996) parametrizations are widely used in the GCM radiation scheme. However, the validity of the data is limited to an effective radius (size) of 130 or 140 μm. This limit exceeds the median of the effective radius of snow (~200 μm), which is computed from the multi-class cloud microphysics scheme. A comparable amount of snow exists in the upper atmosphere near the lower part of ice clouds. Although the cross section of snow (extinction probability) is smaller than cloud ice, its impact on radiation has not been properly considered so far. We constructed a new lookup table of optical properties based on recent data for an extended effective radius up to 500 μm. The old data (< 130 μm) also need to be updated with a more recent and elaborate method. We processed extensive data provided by Yang et al. (2013) and linked to the radiation module of the Korean Integrated Model (KIM). The new optical properties change the shortwave scattering features, thus increasing the heating rate. This tendency is checked in both one-dimensional and global weather forecast simulations. With the new optical properties, KIM shows better performance by reducing bias with respect to the Integrated Forecasting Systems (IFS) analysis data.
关键词： weather forecasting,optical properties,cloud microphysics,ice crystals,radiation scheme
更新于2025-09-23 15:21:21
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Lab and test beam results of irradiated silicon sensors with modified ATLAS pixel implantations
摘要： In Dortmund, planar silicon pixel sensors were designed with modified n+-implantations and produced in n+-in-n sensor technology. Baseline for these new designs was the layout of the IBL planar silicon pixel sensor with a 250 μm × 50 μm pitch. The different implantation shapes are intended to cause electrical field strength maxima to increase charge collection after irradiation and thus increase particle detection efficiency. To test and compare the different pixel designs, the modified pixel designs and the standard IBL design are placed on one sensor which can be read out by a FE-I4. After irradiation with protons and neutrons respectively the performance of several sensors is tested in laboratory and test beam measurements. The presented laboratory results verify that all sensors are fully functional after irradiation. The the test beam measurements show different results for sensors irradiated to the same fluence with neutrons in Sandia compared to sensors irradiated with neutrons in Ljubljana or with protons at CERN PS.
关键词： Particle tracking detectors (Solid-state detectors),Radiation-hard detectors,Particle tracking detectors,Solid state detectors
更新于2025-09-23 15:21:21