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Through quantitative statistics and morphological characterization of ceramic fragments for ceramic composite bulletproof insert plates (CCBIPs), distribution characteristics of ceramic fragments within a specific size range were analyzed for different Armor Piercing Incendiary (API) and shot times. To quantitatively evaluate the effect of energy absorption for ceramic plates, a model of energy absorption during penetration for CCBIPs was established based on statistics of the size distribution of ceramic fragments (SDCF). Variation in the SDCF and its influence on energy absorption for CCBIPs were investigated. The results indicate that the distribution feature of ceramic fragments in the range of 0.25–2.25 mm is Gaussian distribution. Compared with Type 56 of API (56-API), ceramic fragments formed by 53-API with higher kinetic energy possess more quantity and more concentrated distribution, whose average equivalence size decreases by 6.5%, corresponding to increasing by 83.9% of estimated energy absorption. Besides, the ability of CCBIPs to resist the third shot is significantly weakened, whose estimated energy absorption decreases by 58.8% compared with the first shot. More concentrated distribution and fewer fragments are formed after the third shot, the average equivalence size of ceramic fragments increases by 6.9%, which may attribute to the micro-cracks induced by the previous two shots.

A Phase-shifted full-bridge (PSFB) converter is widely used in various applications due to its soft-switching characteristics. However, one of the recognized shortcomings of the PSFB converter is that it cannot simultaneously have a wide soft switching range and a small secondary-side duty cycle loss. The shortcoming hinders the high frequency and high efficiency of the converter. In this paper, the change of the energy demand of the converter on the external series inductor with input voltage and load is analyzed. On this basis, a variable saturation inductor with controllable energy is proposed to meet the energy demand and solve the problem of core heating. The controllable change characteristics of the inductor energy are studied directly instead of the controllable change of the inductance value. By adjusting the inductor energy, the PSFB can not only achieve soft switching under light loads, but also reduce duty cycle loss under heavy loads. Theoretical analysis and experimental verification are carried out on the soft switching and duty cycle loss of the converter. Since the transformer ratio can be increased due to the smaller duty cycle loss. The efficiency of the converter can be further improved.

In this work, the impact of the doping process on the photoluminescence emission of CaWO4 as a function of the concentration of Eu3+ cation (0.01 mol%, 0.02 mol%, 0.04 mol%, 0.06 mol%, 0.08 mol%, and 0.10 mol%) is discussed in detail. Ca1−xWO4:xEu3+ samples were successfully synthesized by a simple co-precipitation method followed by microwave irradiation. The blue shift in the absorption edge confirmed the quantum confinement effect and the band gap energy cover the range from 3.91 to 4.18 eV, as the amount of Eu3+ cations increases. The experimental results are sustained by first-principles calculations, at the density functional theory level, to decipher the geometry and electronic properties, thereby enabling a more accurate and direct comparison between theory and experiment for the Ca1−xWO4:xEu3+ structure. Funding for open access charge: CRUE-Universitat Jaume I

Several crucial and impactful three-dimensional (3D) printing applications have been developed within a broad range of fields. Among these, revolutionary changes in health care are highly anticipat...

Many underground engineering projects show that rockburst can occur in rocks at great depth and high temperature, and temperature is a critical factor affecting the intensity of rockburst. In general, temperature can affect the energy storage, dissipation, and surplus in rock. To explore the influence of temperature on the energy storage and dissipation characteristics and rockburst proneness, the present study has carried out a range of the uniaxial compression (UC) and single-cyclic loading–unloading uniaxial compression (SCLUC) tests on pre-heated granite specimens at 20 °C to 700 °C. The results demonstrate that the rockburst proneness of pre-heated granite initially increases and subsequently decreases with the increase of temperature. The temperature of 300 °C has been found to be the threshold for rockburst proneness. Meanwhile, it is found that the elastic strain energy density increases linearly with the total input strain energy density for the pre-heated granites, confirming that the linear energy property of granite has not been altered by temperature. According to this inherent property, the peak elastic strain energy of pre-heated granites can be calculated accurately. On this basis, utilising the residual elastic energy index, the rockburst proneness of pre-heated granite can be determined quantitatively. The obtained results from high to low are: 317.9 kJ/m3 (300 °C), 264.1 kJ/m3(100 °C), 260.6 kJ/m3 (20 °C), 235.5 kJ/m3 (500 °C), 158.9 kJ/m3 (700 °C), which are consistent with the intensity of actual rockburst for specimens. In addition, the relationship between temperature and energy storage capacity (ESC) of granite was discussed, revealing that high temperature impairs ESC of rocks, which is essential for reducing the rockburst proneness. This study provides some new insights into the rockburst proneness evaluation in high-temperature rock engineering.

In the inductive charging scenario of an electric vehicle (EV), the charger should have the capability to flexibly regulate the output power regardless of the misalignment and EV battery voltage. This paper proposes a hybrid voltage and frequency tuning strategy for a series-series (SS) inductive power transfer (IPT) system to regulate power through 0 to 3.3kW at any battery voltages and misalignment conditions without using additional converters. A voltage tuning is used to achieve full-power of 3.3kW and partly contribute to reducing the power. When the input voltage achieves the lower limit, a frequency tuning is used to further decrease the power to 0W, achieving the regulation through 0 to full power. The practical charging region is specified by 110mm airgap, 100mm misalignment in both x and y directions, and 180V-240V battery voltage range. Experiments are carried out at various conditions, and it shows that with an input voltage range of 180V-380V and a frequency of 82.5kHz~87.9kHz, the charging power can be regulated between 100W and 3.3kW at any case in the specified working region. In addition, a peak dc-dc efficiency of 95.7% is achieved at 3.29 kW.

In many energy and combustion applications, particles experience large temperature gradients, which can affect the coagulation process due to thermophoresis. This study presents a rigorous theory of thermophoretically modified Brownian coagulation in the entire particle size regime. The theoretical derivations are based on the kinetic theory for the free-molecular regime and the harmonic mean method for the transition regime. The coagulation kernels in different size regimes can be expressed as the basic Brownian coagulation kernel times an enhancement factor. The enhancement factor represents the coagulation rate enhancement induced by thermophoresis and is a function of specific dimensionless numbers. Based on the enhancement factor, the thermophoretic enhancement effects on particle coagulation are further analyzed under a wide range of gas and particle conditions. The results show that thermophoretic enhancement effects are ignorable in the free-molecular regime, but need to be considered in the continuum regime and the transition regime. In addition, the enhancement effects increase significantly with increase of gas temperature and temperature gradient while decrease with increase of gas pressure. The present study can improve understanding of thermophoretic effects on Brownian coagulation in the entire size regime and provide a useful tool to calculate the coagulation rates in presence of thermophoresis.

The intensities and phase profiles of the elliptic optics vortex beam both are determined by the topological charge (TC) and ellipticity. This paper presents an efficient and simple method for measuring the TC and ellipticity of elliptic vortex. By observing the diffraction patterns, the TC modulus and ellipticity can be probed with the suitable rectangular aperture, and the TC sign can be detected with the suitable right triangular aperture. The scheme works well even for high-order elliptic vortex with topological charge value as high as ± 18, and ellipticity range from 0.5 to 2 at least. Obviously, the measurement of TC and ellipticity have important research value for promoting the application of elliptical vortex.

Renewable solid sorbents for CO2 capture and storage have shown great potentials for the sake of gaseous separation, tail gas treatment, environmental regulation and climate governance. However, current existed preparation and reusability of solid sorbents are generally subject to high energy consumption and complicated procedure. Herein, a light-controlled CO2 separation system with high working temperature resulting from natural sawdust combined with polyethyleneimine is fabricated, which involves low energy input and few operating sequences. This system shows a direct and ratiometric response to sunlight illumination by which CO2 can be reversibly adsorbed and released. This light-controlled CO2 separation process is prospective to become an attractive alternative to traditional alkaline CO2 collection method in terms of its convenience and low cost. As a practical demonstration, CO2 mixed with N2 is successfully separated through this light-controlled carbon capture and storage (CCS) system, which offers great promise for CO2 capture and enrichment with applicability across a wide range of scales.

Tomographic imaging with radionuclides commonly used in nuclear medicine, such as $^{111}$In (171 and 245 keV) and $^{131}$I (364 keV), is in high demand for medical applications and small animal imaging. The Si/CdTe Compton camera with its high angular and high energy resolutions is an especially promising detector to extend the energy coverage for imaging to the range that covers gamma-ray emitted from these radionuclides. Here, we take the first steps towards short-distance imaging by conducting experiments using three-dimensional phantoms composed of multiple sphere-like solutions of $^{111}$In and $^{131}$I with a diameter of 2.7 mm, placed at a distance of 41 mm. Using simple back-projection methods, the positions of the sources are reproduced with a spatial resolution of 11.5 mm and 9.0 mm (FWHM) for $^{111}$In and $^{131}$I, respectively. We found that a LM-MLEM method gives a better resolution of 4.0 mm and 2.7 mm (FWHM). We resolve source positions of a tetrahedron structure with a source-to-source separation of 28 mm. These findings demonstrate that Compton Cameras have the potential of close-distance imaging of radioisotopes distributions in the energy range below 400 keV.

The effect of mechanical strength of the dispersed particle gels (DPG) on their macro plugging performances is significant, however, little study has been reported. In this paper, DPG particles with different mechanical strengths were obtained by mechanical shearing of bulk gels prepared with different formula. Young's moduli of DPG particles on the micro and nano scales were measured by atomic force microscope for the first time. The mapping relationship among the formula of bulk gel, the Young's moduli of the DPG particles and the final plugging performance was established. The results showed that when the Young's moduli of the DPG particles increased from 82 to 328 Pa, the plugging rate increased significantly from 91.46% to 97.10% due to the distinctly enhanced stacking density and strength at this range. While when the Young's moduli of the DPG particles surpassed 328 Pa, the further increase of plugging rate with the Young's moduli of the DPG particles became insignificant. These results indicated that the improvement of plugging rate was more efficient by adjusting the Young’s moduli of the DPG particles within certain ranges, providing guidance for improving the macroscopic application properties of DPG systems in reservoir heterogeneity regulation.

One important aspect in capacitor switching concerns the high inrush current during the energizing of the capacitor. One peculiarity of capacitor switching is the high rate of switching operations easily achieving 1000 operations. Two vacuum breakers were operated up to 1000 times in a simple test circuit simulating the making of high inrush currents. According to standards, peak and frequency of inrush currents are 20 kA and 4200 Hz for back-to-back switching. The range of inrush currents was extended here to peak currents up to 60 kA and frequencies up to 24 kHz. Peak current and frequency have an important impact on radius and current density of the associated arc, and thus on the energy deposited under the arc roots. Under the conditions prevailing here, the whole surface of the contacts appear uniformly melted to a depth of less than 1 mm after 1000 operations. It is obvious that the arc moves across the contact surface driven by the radial magnetic forces generated by this kind of contact. It seems that high peak inrush currents in combination with high inrush frequencies melt the contact surfaces more severe than inrush currents with lower frequencies.

A kind of phase change material (PCM)-based nanocomposite was prepared and added into high energy propellants containing RDX as additives to investigate its effect on thermal decomposition and burning characteristic of high energy propellants. The effect of PCM-based nanocomposites on thermal decomposition of high energy propellants is investigated by TG/DSC-FTIR-MS technology. Due to the delayed protection effect (PCM-based nanocomposites can absorb lots of heat at the range of certain temperature when it undergoes structure change or phase transitions) of PCM-based nanocomposites under the thermal decomposition condition, the thermal stability of high energy propellants modified with PCM-based nanocomposites is improved. At the same time, the concentration of N2, NO2, H2O and CO2 is increased during thermal decomposition of high energy propellants whereas NO and CO is decreased. The burning gaseous products and burning characteristic of high energy propellants are studied by the combination of closed bomb test and Fourier transform infrared spectrum. The main burning gaseous products are N2, CO2, CO, H2O, CH4, etc. After the high energy propellant modified with PCM-based nanocomposites, the concentration of CH4 is increased while CO, CO2 and H2O is decreased under the high-pressure burning condition. The progressivity factor of high energy propellants is increased by 22.2% compared with the control sample while the maximum pressure is merely decreased 1.25% after the addition of the PCM-based nanocomposite, thus PCM-based nanocomposites can be used to adjust the burning process and improve the burning progressivity of high energy propellants. This study is expected to boost the practical application of PCM-based nanocomposite to the propellant formulation and effectively control the burning characteristic of high energy propellants.

The effects of the long range electrostatic interaction in twisted bilayer graphene are described using the Hartree-Fock approximation. The results show a significant dependence of the band widths and shapes on electron filling, and the existence of broken symmetry phases at many densities, either valley/spin polarized, with broken sublattice symmetry, or both., Comment: Invited contribution to a special issue of Nano Materials Science. 12 pages, 8 figures. arXiv admin note: substantial text overlap with arXiv:2004.01577

In proton therapy, a highly conformal proton dose can be delivered to the tumor by means of the steep distal dose penumbra at the end of the beam range. The proton beam range, however, is highly sensitive to range uncertainty, which makes accurately locating the proton range in the patient difficult. In-vivo range verification is a method to manage range uncertainty, one of the promising techniques being prompt gamma imaging (PGI). In earlier studies, we proposed gamma electron vertex imaging (GEVI), and constructed a proof-of-principle system. The system successfully demonstrated the GEVI imaging principle for therapeutic proton pencil beams without scanning, but showed some limitations under clinical conditions, particularly for pencil beam scanning proton therapy. In the present study, we upgraded the GEVI system in several aspects and tested the performance improvements such as for range-shift verification in the context of line scanning proton treatment. Specifically, the system showed better performance in obtaining accurate prompt gamma (PG) distributions in the clinical environment. Furthermore, high shift-detection sensitivity and accuracy were shown under various range-shift conditions using line scanning proton beams.

The purpose of this study was to determine how the characteristics of the data acquisition (DAQ) electronics of a Compton camera (CC) affect the quality of the recorded prompt gamma (PG) interaction data and the reconstructed images, during clinical proton beam delivery. We used the Monte-Carlo-plus-Detector-Effect (MCDE) model to simulate the delivery of a 150 MeV clinical proton pencil beam to a tissue-equivalent plastic phantom. With the MCDE model we analyzed how the recorded PG interaction data changed as two characteristics of the DAQ electronics of a CC were changed: (1) the number of data readout channels; and (2) the active charge collection, readout, and reset time. As the proton beam dose rate increased, the number of recorded PG single-, double-, and triple-scatter events decreased by a factor of 60× for the current DAQ configuration of the CC. However, as the DAQ readout channels were increased and the readout/reset timing decreased, the number of recorded events decreased by

This paper presents a monolithically integrated E-band amplifier multiplier chain (AMC) developed in 130 nm SiGe BiCMOS process. This E-band AMC is composed of a 25 GHz 1:1 power divider, two 25 GHz driver amplifiers (DA 1,2 ), a 75 GHz passive frequency tripler, and a 75 GHz power amplifier (PA). By applying a bypass tuning capacitor based power enhancing technique in the single-ended DA and PA, the output power and power-added-efficiency (PAE) of the AMC have been effectively improved. Benefiting from the proposed passive tripler core with second harmonic suppression function, and the impedance matching network with frequency selection characteristics, the AMC presents better harmonic suppression performance compared with the conventional topology. The bias circuits with temperature compensation are applied to the DA and PA to ensure the performance of the AMC when the temperature changes. The AMC has a measured output power exceeding 0 dBm in the entire E-band frequency range with a peak output power of 10.9 dBm at 77 GHz, and exhibits a record PAE of 8.25 %. Within the 3 dB operating frequency range from 69 to 87 GHz, the rejection of fundamental and second harmonics are better than 33.5 dB. The AMC can work properly between -40 °C and 125 °C with the proposed temperature compensation bias circuits.

An ultra-wide-angle frequency beam scanning leaky wave antenna (LWA) with high scanning rate based on spoof surface plasmon polaritons (SSPPs) waveguide is proposed in this communication. A row of elliptical patches is placed periodically near the SSPPs waveguide, which can shift the fundamental mode of SSPPs waveguide to the fast-wave region and radiate electromagnetic (EM) waves. The simulated results show that the proposed LWA achieves an ultra-wide scanning angle range of 172° over a narrow operation bandwidth of 9.8-12.28GHz, which implies a high scanning rate. The simulated average gain of the proposed LWA is 10.13dBi and its average total efficiency is 75.35%. The proposed LWA is fabricated and measured. The measured scanning angle range is 167° in the frequency band of 9.9-12.25GHz, and the measured average gain is 9.73dBi. Good agreements between the simulated and measured results are obtained, validating the proposed design.

Fully resolved numerical simulations of a micron-sized spherical particle residing on a surface with large-scale roughness are performed by using the Lattice–Boltzmann method. The aim is to investigate the influence of surface roughness on the detachment of fine drug particles from larger carrier particles for transporting fine drug particles in a DPI (dry powder inhaler). Often the carrier surface is modified by mechanical treatments for modifying the surface roughness in order to reduce the adhesion force of drug particles. Therefore, drug particle removal from the carrier surface is equivalent to the detachment of a sphere from a rough plane surface. Here a sphere with a diameter of 5 μm at a particle Reynolds number of 1.0, 3.5 and 10 are considered. The surface roughness is described as regularly spaced semi-cylindrical asperities (with the axes oriented normal to the flow direction) on a smooth surface. The influence of asperity distance and size ratio (i.e. the radius of the semi-cylinder to the particle radius, Rc/Rd) on particle adhesion and detachment are studied. The asperity distance is varied in the range 1.2

Optical tunneling is an effect extremely sensitive to wavelength changes. In this article, we use this effect to design a new type of biosensor. The tunneling effect is excited by long range surface plasmon resonance, the energy is concentrated in the sensing medium in the form of standing waves, which lead a very high wavelength sensitivity and quality factor. By using COMSOL for finite element analysis, for the sensor structure of BK7/Cytop /Al2O3/Ag/Al2O3/sensing media/air, a quality factor of 10296 RIU-1 is achieved under angle modulation, a sensitivity of 170,000 nm/ RIU and a quality factor of 11333 RIU-1 are obtained under wavelength modulation. At the same time, the advantage of this structure is that there is no excessive requirement on the refractive index of the material, and a good sensing effect can be achieved even if the material is cheap and easy to prepare. After optimization, this structure is suitable for sensing media with a refractive index of 1.335-1.375, which can be applied to most liquid solutions.

The mass attenuation coefficients (μm) of polyethylene glycol (PEG) of different molecular weights (1000–200,000) were measured using single-beam photon transmission. The X-ray fluorescent (XRF) photons from Zinc (Zn), Zirconium (Zr), Molybdenum (Mo), Silver (Ag) and Cadmium (Cd) targets were used to determine the attenuation of gamma radiation of energy range between 8.67 and 23.19 keV in PEG samples. The results were compared to theoretical values using XCOM and Monte Carlo simulation using Geant4 toolkit which was developed to validate the experiment at those certain energies. The mass attenuation coefficients were then used to compute the effective atomic numbers, electron density and half value layers for the studied samples. The outcomes showed good agreement between experimental and simulated results with those calculated theoretically by XCOM within 5% deviation. The PEG 1000 sample showed slightly higher μm value compared with the other samples. The dependence of the photon energy and PEG composition on the values of μm and HVL were investigated and discussed. In addition, the values of Zeff and Neff for all PEG samples behaved similarly in the given photon energy range, and they decreased as the photon energy increased.

Ensembles of parallel nanowires, consists of the parts from different ferro-magnetic metals (for example-FeNi/Co/FeNi) were obtained by method of template synthesis. It was shown that such samples could be the sources of electromagnetic emission – irradiation of Terahertz range. It could be detected when current passed through the contacts at the sample with these wires. The methods of obtaining nanowires was proposed (two-bath galvanic technique), formation of contact layers at the surface (parallel narrow strips of metal) were proposed. The features of these radiation were investigated–it‘s threshold character, it‘s non-thermal origin and spatial distribution. The calculation was also presented, which demonstrated possibility of detecting of Terahertz irradiation, using ensemble of such nanowires, included ferro-magnetic metal and anti-ferromagnetic metal.

This paper presents a multi-mode boost converter to achieve the high efficiency over a wide input voltage range for thermoelectric energy harvesting (TEH) applications. Under high, medium, and low input voltages, continuous conduction mode (CCM), critical conduction mode (CRM), and discontinuous conduction mode (DCM) are adopted to improve the conversion efficiency, respectively. Moreover, a constant peak current (CPC) control scheme is proposed to realize high efficiency under ultra-low input voltage. The proposed converter is implemented in a 0.18 μm standard CMOS process, which occupies a chip core area of about 1.0 mm x 0.9 mm. It achieves >60% efficiency in the range of TEG open-circuit voltage $V_{S}$ from 20 mV to 500 mV, and a peak efficiency of 91.4%. Moreover, after the startup is completed, an efficiency of 37.1% under the $V_{S}$ as low as 10 mV can be achieved.

Most of current centrifugal classifiers can only obtain coarse products and fine products. With the development of industry, particles with different average particle sizes and narrower distribution widths are required. In order to obtain the product in a specified range, classification has to be carried out repeatedly, resulting in higher time and energy cost. For this problem, a novel air classifier that can obtain multi-product with different particle size was designed. Because of the different trajectories of particles with different sizes, particles are sorted and separated in the classifier and flow into different outlets, where a variety of products with increasing average particle size were obtained. There are many feasible matching schemes that the particles do not hit the classifier wall and make full use of classifier space. CFD is employed to investigate particles distribution law and flow field character at different matching schemes, the effect of particle classification at different particles distribution law. Classification size ratio (CSR) is used to evaluate separation effectiveness, the greater CSR, the better separation effectiveness. Experiment results show when the accelerating flow field velocity is 4m/s, the classifying flow field angle is 60°, the CSR at outlet 1∼5 is 3.99, 1.56, 0.96, 0.61, 0.5. As the accelerating flow field velocity increase from 4 m/s to 7 m/s, the separation effectiveness is slightly improved, CSR increase to 4.55, 1.77, 1.03, 0.68, 0.54. There are obvious differences in CSR between adjacent outlet, which shows a variety of products can be obtain in multi-product classifier.

We report and analyze the supermode switching with current injection found for coherently-coupled dual-element vertical cavity surface emitting laser arrays. The output power, spectral characteristics, and far-field mode profile are measured for a range of bias current operating conditions. The coupling-induced enhanced output power from an in-phase or out-of-phase supermode is confirmed when approximately equal currents are injected into each array element. We observe that the coherent supermode switches from out-of-phase to in-phase supermode with increasing equal current injection. The switching is found to be consistent with coupled mode theory and a 1-dimensional spatial supermode model. The calculated modal gain of the out-of-phase and in-phase array supermodes are consistent with the observed switching of the coherent supermodes.

A thorough understanding of chemical composition, particle pH, and pollutant emissions is essential to address the climate and human health effects of atmospheric particles. In this study, we used a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and Scanning Mobility Particle Sizer (SMPS) to characterize the composition of submicron particles. Moreover, we applied the ISORROPIA-II model to analyze the particle acidity effect on the compositional characterization of submicron particles from December 22, 2016 to January 7, 2017 in Albany, New York, USA. The results indicated that aerosols with mobility diameter from SMPS in the range 200–400 nm were the main contributors to the mass during the measurement period. The dominance of organics (47%) and sulfate (16%) was similar to previous observations in the eastern United States in Winter 2015, while the fraction of nitrate (23%) was much higher. Moreover, nitrate could easily form at colder temperatures and lower RH levels even when there were more acidic particle periods during the measurement period in Albany. The ISORROPIA-II model indicated that there were more acidic particles, which was estimated using pH values. Lower temperature conditions tended to favor nitrate formation. The nitrate concentration exceeded that of sulfate in the measurement period, even though the SO2 and NOx emissions were similar. The organics in submicron particles were strongly influenced by the local emissions in winter. However, the inorganic compounds in submicron particles could be derived from regional transport as their pollution sources originated from different directions. This may help strategize emission reductions in the future.

Molecular rotors are an important class of dynamic molecules which have been studied not only for their possible uses as components of molecular machines but also because of potential applications as probes of local viscosity in biological media, especially self-assembled membranes. For the former, factors affecting rotational motility are critical while for the latter the rotor activity must be complexed with an output signal (often fluorescence) for reporting of local conditions. Molecular single stator-double rotor activity of an oxidized resorcinarene (fuchsonarene) macrocycle containing unsaturated hemiquinonoid groups at its meso positions was investigated. Fuchsonarenes contain two hemiquinonoid substituents at diagonally-opposed meso-positions with two electron rich phenol groups at the remaining meso-positions between the hemiquinonoid groups. All meso-substituents are in proximity at one side of the resorcinarene macrocycle (so-called rccc-type isomer) with rotational activity of the phenol meso-substituents. Rotation rates of the phenol moieties can be controlled by varying temperature, solvent polarity and acidity of the medium of study with rotation being thermally activated in neutral and acidic media and tunable in the range from 2 s−1 to 20 000 s−1. Experimental and computational data indicate that rotation of the mobile phenol meso-substituents is remotely affected by interactions with acidic solvents at the carbonyl CO groups of macrocyclic acetyloxy groups, which occurs with the emergence of a lower energy electronic absorption band whose intensity is correlated with both the acidity of the medium and the rotation rate of the phenol substituents. Time-dependent DFT calculations suggest that the low energy band is due to a molecular conformational adjustment affecting electronic conjugation caused by strong interaction of macrocyclic acetyloxy carbonyl groups with the acid medium. The work presents a molecular mechanical model for estimating solution acidity and also gives insight into a possible method for modulating rotor activity in molecular machines.

The archetypical transcriptional crcB fluoride riboswitch from Bacillus cereus is an intricately structured non-coding RNA element enhancing gene expression in response to toxic levels of fluoride. Here, we used single molecule FRET to uncover three dynamically interconverting conformations appearing along the transcription process: two distinct undocked states and one pseudoknotted docked state. We find that the fluoride anion specifically snap-locks the magnesium-induced, dynamically docked state. The long-range, nesting, single base pair A40-U48 acts as the main linchpin, rather than the multiple base pairs comprising the pseudoknot. We observe that the proximally paused RNA polymerase further fine-tunes the free energy to promote riboswitch docking. Finally, we show that fluoride binding at short transcript lengths is an early step toward partitioning folding into the docked conformation. These results reveal how the anionic fluoride ion cooperates with the magnesium-associated RNA to govern regulation of downstream genes needed for fluoride detoxification of the cell., A single molecule fluorescence study revealed three dynamically interconverting conformations of the fluoride riboswitch from Bacillus cereus, where an anionic ligand snap-locks a docked conformation through a long-range interaction necessary for downstream gene regulation.

Graphitic carbon nitride (g-C3N4) has aroused wide concern in the domain of photocatalytic hydrogen production owing to its excellent advantages. However, the high recombination rate of photoinduced electron-hole pairs and finite surface area limit the photocatalytic performance of g-C3N4. In this demonstration, g-C3N4 photocatalytic material (VCN) with rich pore structures and carbon vacancies was obtained by heat-treating of g-C3N4 in NH3 atmosphere. The pore structures endow VCN with a higher specific surface area and new active surfaces. Meanwhile, introduction of carbon vacancies increases the electrical conductivity of VCN and the mobility of photoinduced carriers, which markedly enhances the separation efficiency of photoexcited carriers. Furthermore, VCN also shows a wider light response range and stronger visible light absorption capacity. Therefore, VCN has a better photocatalytic hydrogen evolution performance with visible light than the pristine g-C3N4, and photocatalytic hydrogen evolution performance of VCN is approximately 4.4 times that of the pristine g-C3N4.

The suppression of high-intensity blob structures in the scrape-off layer (SOL) by ion-cyclotron range of frequencies (ICRF) power, leading to a decrease in the turbulent fluctuation level, is observed first in the Experimental Advanced Superconducting Tokamak (EAST) experiment. This suppression effect from ICRF power injection is global in the whole SOL at EAST, i.e. blob structures both in the regions that are magnetically connected to the active ICRF launcher and in the regions that are not connected to the active ICRF launcher could be suppressed by ICRF power. However, more ICRF power is required to reach the full blob structure suppression effect in the regions that are magnetically unconnected to the active launcher than in the regions that are magnetically connected to the active launcher. Studies show that a possible reason for the blob suppression could be the enhanced E r × B shear flow in the SOL, which is supported by the shaper radial gradient in the floating potential profiles sensed by the divertor probe arrays with increasing ICRF power. The local RF wave power unabsorbed by the core plasma is responsible for the modification of potential profiles in the SOL regions.

The charge distributions and elastic electron form factors for 18O, 42,44Ca, 58Ni, and 118Sn nuclei were considered using the cluster expansion of the 1- and 2-body terms. Inelastic electron form factors to 2+ states with core-polarization effects were studied, where the nuclear collective modes were considered alongside the shell model transition density. The influence of short-range correlations (SRCs) was calculated by the parameter β, which was introduced into the ground-state charge distribution and concluded the Jastrow-type function. It is found that the inclusion of 2-body correlations is necessary to describe the observed data of elastic and inelastic form factors at high momentum transfer q > 3 fm–1.

In this study, the temperature and volume fraction distributions of liquid silicon nanoparticles in the aerosol flow in gas-phase synthesis were retrieved using tomographic reconstruction of emission and extinction spectra in the 230–700 nm range. Measurements were done in an optically accessible microwave-plasma flow reactor fed with a SiH4/H2/Ar gas mixture. Optical emission and extinction spectra in the visible spectral range were captured along a line perpendicular to the flow direction covering the entire cross-section of the Si particle stream. Particle temperature and volume fraction distributions were determined and the preferred location of the silicon particles in a 1-mm thick zone at the circumference of the cylindric flow was revealed. The combined recording of line-resolved emission/extinction spectra is a promising method for spatially-resolved detection of nanoparticles in combustion or gas-phase synthesis.

This study explores the effective use of a spectral area defined by a radiation source for multipoint measurements with fiber-optic Bragg sensors (FBG). The capacity of the sensor network based on a wavelength multiplex is limited by the spectral work area of the used radiation source and by several other parameters, such as the spectral parameters of individual sensors, type of the measured quantity and measurement range, sensitivity coefficients, production tolerances, and protection zones among the measuring channels. That is why it is necessary to use this limited area in an “economical” manner. The initial part of the article explores modelling of sensor networks using Bragg gratings, an output of which is an analysis of the impact of individual parameters on the capacity of a sensor network. These models are then applied to the mathematical definition of the given network proposal formed by real sensors. At the end, the stated principles are verified by real measurements with a sensor network formed by 5 Bragg sensors. The study points to the necessity of paying close attention to the proposals of sensor networks with FBG for the purpose of the effective use of the given spectral work area, increasing capacity and reducing the possibility of crosstalk when assessing the Bragg sensors.

Zinc-ion hybrid supercapacitors (ZHCs), based on the multivalent ion storage principle, are considered to be a promising candidate for large-scale energy storage devices. However, with the increasing demands for portable and miniaturized energy storage devices, how to obtain sufficient energy output in a limited volume is particularly critical, so that requires high volumetric energy density with no sacrifice of power density. Herein, we designed a compact three-dimensional porous graphene (3D-PG-1) cathode for ZHCs to balance the porous structure and high density by drying the graphene hydrogel with a short period of capillary evaporation. As for 3D-PG-1, the pore size range is 0.6–10 nm, where the micropore is for high capacity and the mesopore helps Zn2+ rapid transport, and the high density of 1.38 g cm−3 guaranteed its high volumetric capacitance. Therefore, the ZHC based on this 3D-PG-1 cathode delivered an excellent volumetric performance of 299 F cm−3 at 0.1 A g−1, excellent long cycle stability (225 F cm−3 at 5 A g−1, 85% retention after 30000 cycles) and extremely high volumetric energy density up to 118 Wh L−1 at 116 W L−1, which retained 61 Wh L−1 at the power density as high as 23.2 kW L−1.

This paper presents an efficient synthesis method for generating vortex beams based on donut-shaped orbital angular momentum (OAM) metasurfaces. It not only allows one to synthesize the vortex beam with an arbitrary combination of OAM modes and arbitrary mode energy distribution, but also avoids the undesired phase singularities in the conventional OAM metasurfaces. Three specific examples are implemented to verify the effectiveness of the synthesis method including single-mode, multi-mode, and equal-amplitude vortex beams. Based on the proposed constraint conditions, a donut-shaped metasurface is designed to generate a high-purity single-mode vortex beam. To generate high-performance multi-mode beams, a shape-related tailoring is further introduced to avoid the undesired phase singularities of the multi-mode OAM metasurfaces. Finally, the synthesized equal-amplitude vortex beams are generated and verified experimentally over a wide frequency range, which demonstrates robust and precise control of the vortex beams.

In this study, the feasibility of a new launcher concept that provides range extension for outdated ballistic munitions by speeding up them before their ignition is examined in detail. To analyze the efficiency of the new concept, multi-variable and single-variable optimization processes are conducted using the Multi-Objective Genetic Algorithm Method in the ModeFrontier environment. Launch angle, ejection velocity of the munition from the launcher, and ignition delay of the rocket motor after the ejection process are determined as design variables. An in-house MATLAB script is prepared and validated to perform numerical solutions of the munition’s two-dimensional trajectory. As a result of the optimization processes, graphical results are prepared to examine the effects of each design variable on munition’s range and to make a comparison between the flight trajectories of the munitions which are launched from classical and accelerator launchers. It is concluded that usage of the accelerator launcher concept provides approximately 20% range extension for the generic munition examined in this research when compared to the classical launcher. Since this new concept can easily be adapted to different types of outdated ballistic munitions and the cost of the accelerator launcher development process will probably less than the cost required to develop new munitions, it will be reasonable to develop accelerator launchers such as electromagnetic accelerators or catapult launchers in near future.

Inertial impactors are an important part of aerosol science where they are used to obtain particle size distributions in a wide range of practical and scientific applications. A shortcoming of thes...

The relationship between SCR and CME and with fading of the continuum of noise storms and typeIV radio bursts in the decameter range is investigated. It was shown earlier that about 60% of CMEs associated with solar proton events are accompanied by deep fading of the solar radio emission in the decameter range, which coin-cides in time with CME registration. It has also been shown that fading is characterized by fading depth, the frequency bandwidth in which the fading occurs, as well as the duration of the fading and the frequency at which the maximum fading depth is observed. Further detailed studies have shown that for proton events accompanied by fading of the solar radio emission in the decameter range, the relationship between the intensity of the SCR proton flux and the CME velocity is much worse than for events without fading of the solar radio emission in the decameter range. However, it was foundthat for such events, the relationship between the flux of SCR protons and the CME velocity significantly increases if we take into account the fading depth of the solar radio emission in the decameter range.Earlier in (Isaeva, 2019), the results of a study of the relationship between the intensity of fading of the continuum of noise storms with the parameters of X-ray bursts, with the CME velocity and the velocity of coronal shock waves, as well as with the intensity of the SCR proton flux were presented. This paper presents the results of studying the relationship between the intensity of the SCR proton flux withthe parameters of type II and IV radio bursts, as well as with the CME velocity and with the velocity of coronal shock waves, depending on the intensity of fading of the solar radio emission in the decameter range at a frequency of 27 MHz. The frequency of 27 MHz was chosen because in the region of this frequency the maximum fading depth of the solar radio emission in the decameter range is observed.

The stability of dispersions containing charged particles may obviously be regulated by salt. In some systems, the effective charge, as measured by the potential some small distance away from the particles, can have a sign opposite to the bare surface charge. If charge reversal takes place, there is typically a salt concentration regime within which colloidal stability increases with added salt. These experimental findings on dispersions have been corroborated by atomic force microscopy investigations, where an attraction is found at short separations. This attraction is stronger than expected from standard DLVO theory, and there has been considerable debate concerning its origin. In this work, we use simple coarse-grained models of these systems, where the bare surfaces carry a uniform charge density, and ion-specific adsorption is absent. Our hypothesis is that these experimental observations can be explained by such a simplistic pure Coulomb based model. Our approach entails grand canonical Metropolis Monte Carlo (MC) simulations as well as correlation-corrected Poisson-Boltzmann (cPB) calculations. In the former case, all ions have a common size, while the cPB utilizes a point-like model. We devote significant attention on apparent surface charge densities and interactions between large flat model surfaces immersed in either a 2:1 salt or a 3:1 salt. In contrast to most of the previous theoretical efforts in this area, we mainly focus on the weak long-ranged repulsion and its connection to an effective surface charge. We find a charge reversal and a concomitant development of a free energy barrier for both salts. The experimentally observed nonmonotonic dependence of colloidal stability on the salt concentration is reproduced using MC simulations as well as cPB calculations. A strong attraction is observed at short range for all investigated cases. We argue that in our model, all non-DLVO aspects can be traced to ion–ion correlations.

Na0.5Bi0.5TiO3-based ceramic specimens have been extensively investigated as ferroelectric materials. After being doped with CaTiO3, the resulting Na0.5Bi0.5TiO3-based ceramics exhibit relaxor characteristics, and improved energy storage density and efficiency. Based on these above results, CeO2 was further employed to modify the polarization of the 0.85Na0.5Bi0.5TiO3-0.15CaTiO3 matrix ceramic to achieve better energy storage performance. The effective energy storage density was enhanced from 1.93 to 2.53 J/cm3 by using the appropriate doping concentration of CeO2. Grain refinement effect can effectively enhance the electric-field strength from approximately 190 to 230 kV/cm. In particular, when doped with 2% CeO2, the energy storage efficiency of the sample was maintained at approximately 90% at 30 °C-150 °C and at approximately 80% in the frequency range of 0.2–200 Hz. This combination has very excellent temperature stability and frequency stability, making it a promising candidate for energy storage applications.

Near-infrared (NIR) optical devices play an important role in non-destructive imaging and detection in vitro. In particular, the NIR-II light has a better penetration depth. Phosphor conversion-LED is a preferred light source, which is highly dependent on the quality of the NIR phosphor. In this work, Cr3+ doped LiScGe2O6 NIR phosphor is synthesized and studied in detail. It can emit NIR-II light peaking at 926 nm at the range of 700–1400 nm, which covers NIR-I area and extends to NIR-II area with Dq/B = 1.69 of Tanabe-Sugano diagram. This phosphor has a very broad absorption band and can be excited by UV, blue, 660, and 808 nm light, respectively. The fabricated NIR LED using our Cr3+ doped LiScGe2O6 phosphor excited by blue chip can penetrate the palm and 1.5 cm pork meat effectively. NIR-II emission with multi spectral responsive in Cr3+ doping inorganic LiScGe2O6 based matrix is achieved for the first time.

The rheological behavior of magnetorheological fluids (MRFs) is greatly influenced by many key parameters such as concentration, composition, temperature, and magnetic field. As magnetic particles are dispersed in a non-magnetic liquid, MRFs exhibit an increase in viscosity with increasing magnetic fields due to the formation of chain-like structures. However, this viscosity change has often been studied as a function of any one or two of the key parameters. Herein, we studied the simultaneous effect of temperature, magnetic field, concentration of dispersed phase, and MRF composition on the viscosity of MRFs. Understanding the simultaneous effect of tunable parameters such as temperature and magnetic field allows for optimization of MRF performance and enhanced viscosity in commercial applications. Rheological experiments were performed on MRFs over a wide range of temperatures (15–65 °C) under magnetic fields between 0.1 and 1 T. The thermo-magnetorheological response was also studied with varying magnetic particle concentration (1 vol%–25 vol%) and MRF composition (both dispersed phase and carrier liquid). The results demonstrated a strong influence of magnetic particle composition and concentration on the MRF viscosity along with temperature while the carrier liquid composition had relatively negligible influence.

In this article, the electrical properties of nMOSFET devices with different high-k Al₂O₃ capping layer thickness and TiN electrode have been systematically studied at deep cryogenic temperatures ranging from 10 to 300 K. The threshold voltage $V_{TH}$ , transconductance $g_{m}$ , carrier mobility μ, mobility attenuation factor θ , and subthreshold swing (SS) are extracted using the $I_{DS}$ - $V_{GS}$ curves and Y-function method at different temperatures. It is indicated that: 1) all the electrical parameters ( $V_{TH}$ , $g_{m}$ , μ, θ , and SS) show strong temperature dependence in the range of studied temperatures and 2) temperature-dependent electrical properties of nMOSFET devices will modulate at various cryogenic temperatures ascribed to the presence of the Al₂O₃ capping layer on the SiO₂ dielectric layer, which increases the oxide trap density and consequentially adjusts the threshold voltage and mobility of the devices.

Here we report tuning of structural parameters of La2Sn2O7 by Nd substitution at La-site in a quest to effectively control the dielectric response as a small variation in lattice parameters can result in large dielectric fluctuations. For this purpose, a series of Nd-substituted La2Sn2O7 was synthesized using sol gel auto-combustion route. The formation of stable cubic pyrochlore phase with consistent variation in the lattice parameters was observed in structural analysis. The morphological investigations revealed a spherical shape of La2Sn2O7 particles which transformed to diamond like shape with a systematic variation in grain size by increasing the Nd contents. The variation in grain size dominantly affected the dielectric dispersion in the vast frequency range. Less energy loss and improved dielectric properties make La1.2Nd0.8Sn2O7 a potential candidate for utilization in energy storage devices. The complex modulus analysis provided an insightful view which helped to distinguish the mobility range of charge carriers in different frequency ranges.

The 13C (α,n)16O reaction cross-section is important data for nuclear physics, astrophysical, and neutrino physics experiments, however, they exhibit uncertainties due to the discrepancies in the experimental data. In this study, using the Nedis-2m program code, the energy spectrum of α-induced neutrons in a thin carbon target was calculated and the corresponding reaction cross-section was refined in the alpha particle energy range of 5–8 MeV. The results were used to calculate the intensity and energy spectrum of background neutrons produced in the liquid scintillator of KamLAND. The results will be useful in a variety of astrophysical and neutrino experiments especially those based on LS or Gd-LS detectors.

In the radiation protection application, the metal-polymer composites have been developed for their radiation shielding properties. In this research, the elastomer composites doped by 10 μm and100nm size of lead, bismuth and tungsten particles as filler with 30 and 60 wt percentages were prepared. To survey the shielding properties of the polymer composites using gamma-ray emitted from 152Eu and 137Cs sources, the gamma flux was measured by using NaI(Tl) detector, then the linear attenuation coefficient was calculated. Also, the Monte Carlo simulation (MCs) method was used. The results showed a direct relationship between the linear attenuation coefficients of the absorbent and filler ratio. Also, the decrease in the particle size of the shielding material in each weight percentage improved the radiation shielding features. When the dimension of the particles was in the order of nano-size, more attenuation was achieved. At low energies used for medical diagnostic X-ray applications due to the predominance of the photoelectric effect, bismuth and lead were suitable selection as filler.

Otsubo, M., Terao, K. Kinetics of the complex formation of silica nanoparticles with collagen. Polym J 53, 1481–1484 (2021). https://doi.org/10.1038/s41428-021-00553-4., Time-resolved small-angle X-ray scattering measurements were made for a mixed solution of negatively charged silica nanoparticles (SiNPs) and positively charged atelocollagen (AC) in buffers at pH = 3 and 4 at 25 °C, in which the scattering intensity from the AC molecules was very weak in the investigated q (magnitude of the scattering vector) range. The scattering intensity from the SiNPs at the low q end and middle q range gradually increased and decreased, respectively, and reached asymptotic values approximately 5–20 min after rapid mixing of the two solutions of SiNPs and AC. This clearly shows that the structural formation of the SiNP–AC complex is on the time scale of minutes. Furthermore, the structure factor at 30 min after mixing is consistent with the previously investigated data for SiNPs and triple helical AC at 15 °C. The obtained time scale to form the complex can be important information to control the aggregating structure of SiNPs with the aid of collagen molecules.

SnTe3O8 crystallizes isotypically with other members of the series M IVTeIV 3O8 (M = Ti, Zr, Hf). It comprises [SnO6] octa­hedra and [TeO4] bis­phenoids as the principal structural building blocks., Tin(IV) trioxidotellurate(IV), SnTe3O8, is a member of the isotypic M IVTeIV 3O8 (M = Ti, Zr, Hf, Sn) series crystallizing with eight formula units per unit cell in space group Ia . In comparison with the previous crystal structure model of SnTe3O8 based on powder X-ray diffraction data [Meunier & Galy (1971 ▸). Acta Cryst. B27, 602–608], the current model based on single-crystal X-ray data is improved in terms of precision and accuracy. Nearly regular [SnO6] octa­hedra (Sn site symmetry . .) are situated in the voids of an oxidotellurate(IV) framework built up by corner-sharing [TeO4] bis­phenoids (Te site symmetry 2..). A qu­anti­tative structural comparison revealed a very high degree of similarity for the structures with M = Ti, Zr, Sn in the M IVTe3O8 series.