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Researchers are used to investigating the influence of surface topography on the frictional electrification of sliding triboelectric nanogenerators TENGs from the perspective of a single-stratum topography; however, a stratified feature has shared reality in closer relationships. Here, we characterize the stratified feature of the topographies for the sliding TENGs, and link them to the electrification voltages, finding that the frictional electrification strongly depends on the characteristics of the small-scale component in a stratified topography, which suggest us to develop a stratified electrification model for mechanism reveal. Based on the dependence, we also succeed in identifying the stratified topographic characteristics with frictional electrification signals by machine learning including support vector machine and convolutional neural network, which can be envisioned as a tool for topography measurement. This is the first demonstration of a stratified topography theory for sliding TENGs, providing new insights into the mechanism reveal and functional application of frictional electrification.

Building exit as a bottleneck structure is the last and the most congested stage in building evacuation. It is well known that obstacles at the exit affect the evacuation process, but few researchers pay attention to the effect of stationary pedestrians (the elderly with slow speed, the injured, and the static evacuation guide) as obstacles at the exit on the evacuation process. This paper explores the influence of the presence of a stationary pedestrian as an obstacle at the exit on the evacuation from experiments and simulations. We use a software, Pathfinder, based on the agent-based model to study the effect of ratios of exit width (D) to distance (d) between the static pedestrian and the exit, the asymmetric structure by shifting the static pedestrian upward, and types of obstacles on evacuation. Results show that the evacuation time of scenes with a static pedestrian is longer than that of scenes with an obstacle due to the unexpected hindering effect of the static pedestrian. Different ratios of D/d have different effects on evacuation efficiency. Among the five D/d ratios in this paper, the evacuation efficiency is the largest when d is equal to 0.75D, and the existence of the static pedestrian has a positive impact on evacuation in this condition. The influence of the asymmetric structure of the static pedestrian on evacuation efficiency is affected by D/d. This study can provide a theoretical basis for crowd management and evacuation plan near the exit of complex buildings and facilities.

Volatile organic compounds (VOCs) are typical pollutants that affect air quality. Discharge plasma is thought to be a potential method that can remove VOCs from flue gas. In this experiment, pulsed corona discharge plasma combined with a biological tower was carried out to remove the benzene series, and toluene was selected as the typical VOC. The results indicated that the removal efficiency of toluene by pulsed corona plasma was slightly higher than that of direct current (DC) corona plasma, while its energy efficiency was much higher than DC corona plasma. Under the optimal experimental conditions of pulse voltage 8.5 kV, initial toluene concentration 1400 mg m−3, and toluene flow rate of 12 l h−1, the toluene removal efficiency reached 77.11% by the single method of pulsed corona discharge plasma, and the energy efficiency was up to 1.515 g/(kW·h) under the pulse voltage of 4.0 kV. The trickling biofilter was constructed by using the screened and domesticated Acinetobacter baumannii, and the highest toluene removal efficiency by the pulsed corona discharge plasma combined with the trickling biofilter rose up to 97.84%. Part of the toluene was degraded into CO2, H2O, and some intermediate products such as o-diphenol under the influence of Acinetobacter baumannii. When the remaining waste gas passed through the discharge plasma reactor, the benzene ring structure could be directly destroyed by the collision between toluene and plasma. Meanwhile, O·, OH·, and some other oxidizing radicals generated by the discharge also join into the oxidative decomposition of toluene and its intermediate products, thereby further improving the removal efficiency of toluene. Therefore, the two-stage plasma-biofilter system not only showed a high toluene removal efficiency, but also had a good energy efficiency. The results of this study will provide theoretical support and technical reference for industrial VOC treatment.

COVID-19 has brought significant impacts on the global economy and environment. The Global Economic-and-environmental Policy Uncertainty (GEPU) index is a critical indicator to measure the uncertainty of global economic policies. Its prediction provides evidence for the good prospect of global economic and environmental policy and recovery. This is the first study using the monthly data of GEPU from January 1997 to January 2022 to predict the GEPU index after the COVID-19 pandemic. Both Recurrent Neural Network (RNN) and Long Short-Term Memory (LSTM) models have been adopted to predict the GEPU. In general, the RNN outperforms the LSTM networks, and most results suggest that the GEPU index will remain stable or decline in the coming year. A few results point to the possibility of a short-term increase in GEPU, but still far from its two peaks during the first year of the COVID-19 pandemic. This forecast confirms that the impact of the epidemic on global economic and environmental policy will continue to wane. Lower economic and environmental policy uncertainty facilitates global economic and environmental recovery. Economic recovery brings more opportunities and a stable macroeconomic environment, which is a positive sign for both investors and businesses. Meanwhile, for the ecological environment, the declining GEPU index marks a gradual reduction in the direct impact of policy uncertainty on sustainable development, but the indirect environmental impact of uncertainty may remain in the long run. Our prediction also provides a reference for subsequent policy formulation and related research.

The fast development of nanomedicine and nanobiotechnology has enabled the emerging of versatile therapeutic modalities with high therapeutic efficiency and biosafety, among which nanosonosensitizer-involved sonodynamic therapy (SDT) employs ultrasound (US) as the exogenous activation source for inducing the production of reactive oxygen species (ROS) and disease therapy. The chemoreactive nanosonosensitizers are the critical components participating in the SDT process, which generally determine the SDT efficiency and therapeutic outcome. Compared to the traditional and mostly explored organic sonosensitizers, the recently developed inorganic chemoreactive nanosonosensitizers feature the distinct high stability, multifunctionality and significantly different SDT mechanism. This review dominantly discusses and highlights two types of inorganic nanosensitizers in sonodynamic treatments of various diseases and their underlying therapeutic mechanism, including US-activated generation of electrons (e−) and holes (h+) for facilitating the following ROS production and delivery of organic molecular sonosensitizers. Especially, this review proposes four strategies aiming for augmenting the SDT efficiency on antitumor and antibacterial applications based on inorganic sonosensitizers, including defect engineering, novel metal coupling, increasing electric conductivity and alleviating tumor hypoxia. The encountered challenges and critical issues facing these inorganic nanosonosensitzers are also highlighted and discussed for advancing their clinical translations.

We theoretically investigate the finite-temperature structure and collective excitations of a self-bound ultradilute Bose droplet in a flat space realized in a binary Bose mixture with attractive inter-species interactions on the verge of mean-field collapse. As the droplet formation relies critically on the repulsive force provided by Lee-Huang-Yang quantum fluctuations, which can be easily compensated by thermal fluctuations, we find a significant temperature effect in the density distribution and collective excitation spectrum of the Bose droplet. A finite-temperature phase diagram as a function of the number of particles is determined. We show that the critical number of particles at the droplet-to-gas transition increases dramatically with increasing temperature. Towards the bulk threshold temperature for thermally destabilizing an infinitely large droplet, we find that the excitation-forbidden, self-evaporation region in the excitation spectrum, predicted earlier by Petrov using a zero-temperature theory, shrinks and eventually disappears. All the collective excitations, including both surface modes and compressional bulk modes, become softened at the droplet-to-gas transition. The predicted temperature effects of a self-bound Bose droplet in this work could be difficult to measure experimentally due to the lack of efficient thermometry at low temperatures. However, these effects may already present in the current cold-atom experiments., Comment: 10 pages, 8 figures; Invited Article to Chinese Physics B for the Special Topic "Ultracold atom and its application in precision measurement"

A great deal of attention has been focused on discharge plasma as it can rapidly decompose N2O without additives, which is not only a kind of greenhouse gas but also a kind of damages to the ozone layer. The thermal equilibrium plasma is chosen to combine with catalysts to decompose N2O, and its characteristics are analyzed in the present paper. The results indicate that NO and NO2 were formed besides N2 and O2 during N2O decomposition when N2O was treated merely by discharge plasma. Concentration of NO declined greatly when the discharge plasma was combined with catalysts. Results of Raman spectra analysis on CeO2, Ce0.75Zr0.25O2 and Ce0.5Zr0.5O2 imply that the products selectivity has been obviously improved in discharge plasma decomposing N2O because of the existence of massive oxygen vacancies over the composite oxide catalysts.

FCNC processes offer important tools to test the Standard Model (SM) and to search for possible new physics. In this work, we investigate the rare hyperon decays in SM and beyond. We find that in SM the branching ratios for these rare hyperon decays range from to . When all the errors in the form factors are included, we find that the final branching ratios for most decay modes have an uncertainty of about 5% to 10%. After taking into account the contribution from new physics, the generalized SUSY extension of SM and the minimal 331 model, the decay widths for these channels can be enhanced by a factor of .

We study the generation of supercontinuum (SC) with spectral wings and temporal ultra-short pulse sequence by pumping two identical time-delayed pulses in an all-normal dispersion fibre. The flat dispersion profile over the entire wavelength range of the generated SC provides an opportunity to divide these ultra-short pulses roughly evenly. By adjusting the time delay, the temporal width of these ultra-short pulses can be regulated considerably, which accelerates the development in numerous fields such as multi-photon microscopy and ultrafast spectroscopy. Besides, the temporal overlap of two pulses at different instantaneous frequencies leads to the emergence of spectral wings via four-wave mixing. By changing the input power and time delay, spectral wings with variable intensities and ranges can be emitted at different distances, which can expand the SC spectral bandwidth within a limited fibre length.

This report demonstrates a dual-wavelength stable Q-switched Er-doped fiber (EDF) laser with a reduced graphene oxide (rGO)-based saturable absorber. The rGO is prepared by depositing the graphene oxide on fluorine mica (FM) using a thermal reduction method. The modulation depth and saturable intensity of rGO/FM are measured to be 5.8% and 73.6 MW cm−2. By employing the rGO/FM film in the EDF laser cavity, stable dual-wavelength Q-switching operation is achieved. The two wavelength peaks locate at 1531.84 nm and 1558.14 nm. The shortest pulse duration is 1.83 µs. The maximum output power is measured to be 14.65 mW, corresponding to the maximum single pulse energy of 154.34 nJ. The experimental results evidently show that the rGO is a promising type of nonlinear material.

A comprehensive study was performed to explore the thermal characteristics of NS-DBD plasma actuation over an airfoil/wing surface and evaluate the anti-/de-icing performance of NS-DBD plasma actuators for aircraft in-flight icing mitigation. While the fundamentals of thermal energy generation and heat transfer in NS-DBD plasma actuation over the airfoil/wing model were described in great details, a series of experiments were conducted to evaluate the effects of different environmental parameters on the heating efficiency of NS-DBD plasma actuators over the airfoil/wing surface. With the temporally-synchronized-and-spatially-resolved high-speed visualization & infrared (IR) imaging system, not only the transient thermal characteristics of NS-DBD plasma actuation over the airfoil/wing surface were revealed, but also the anti-icing performances of the NS-DBD plasma actuators were evaluated under different icing conditions, i.e., rime, mixed, and glaze. The impacts of incoming airflow velocity, air temperature, and angle of attack (AOA) of the airfoil/wing model on the thermal characteristics of NS-DBD plasma actuation over the airfoil/wing surface were systematically investigated based on the measurement results. It was found that the thermal characteristics of NS-DBD plasma actuation over the airfoil/wing surface are closely coupled with the boundary layer airflow and the unsteady heat transfer process over the airfoil/wing model exposed in the frozen-cold airflows. The anti-icing performances of the NS-DBD plasma actuators under the different icing conditions were found to be varying significantly due to the variations of surface heating efficiency of the NS-DBD plasma actuators. The anti-/de-icing performance of the NS-DBD plasma actuators was found to be improved dramatically by increasing the operating frequency of the plasma actuators. The findings derived from the present study are very helpful to explore/optimize design paradigms for the development of novel plasma-based anti-/de-icing strategies tailored specifically for aircraft inflight icing mitigation to ensure safer and more efficient aircraft operation in atmospheric icing conditions.

This study conducted experiments on producing inhaled medical nitric oxide (iNO) by pulsed arc discharge in dry and clean air under different discharge current. The concentration of NO and NO2 produced by air discharge, as well as the change of the ratio of NO2/NO under different discharge current were investigated. Through the analysis of plasma emission spectrum, the relationship between discharge current and arc plasma temperature was studied. The results indicate that, as discharge current increases, the arc plasma temperature increases, which then leads to the increase of NO concentration, the decrease of NO2 concentration, and the rapid decrease of the ratio of NO2/NO. When the plasma temperature is 9000 K, the ratio of NO2/NO is approximately 60%, while when the plasma temperature varies between 10550 K and 11300 K, the NO2/NO ratio is within the range of 4.2% to 4.6%.

By adopting the optical multi-channel analyzer combined with fourier transform infrared (FTIR) spectrometer, the dominant free radicals and products generated by arc discharge were measured and studied, and the main plasma chemical reaction process in the nitric oxide production by arc discharge was identified. Plasma chemical kinetic curves of O, O2, N2, N and NO were simulated by using CHEMKIN and MATLAB. The results show that the main plasma chemical reaction process of nitric oxide production by arc discharge is a replacement reaction between O and N2, where NO can be generated instantaneously when discharging reaches stable.

The Einstein-Podolsky-Rosen (EPR) pair of qubits plays a critical role in many quantum protocol applications such as quantum communication and quantum teleportation. Due to interaction with the environment, an EPR pair might lose its entanglement and can no longer serve as useful quantum resources. On the other hand, it has been suggested that introducing disorder into environment might help to prevent thermalization and improve the preservation of entanglement. Here, we theoretically investigate the time evolution of quantum entanglement of an EPR pair in a random-field XXZ spin chain model in the Anderson localized (AL) and many-body localized (MBL) phase. We find that the entanglement between the qubits decreases and approaches to a plateau in the AL phase, but shows a power-law decrease after some critical time determined by the interaction strength in the MBL phase. Our findings, on one hand, shed lights on applying AL/MBL to improve quantum information storage; on the other hand, can be used as a practical indicator to distinguish the AL and MBL phase.

The Chinese Area Positioning System (CAPS) is a positioning system based on satellite communication that is fundamentally different from the 3``G'' (GPS, GLONASS and GALILEO) systems. The latter use special-purpose navigation satellites to broadcast navigation information generated on-board to users, while the CAPS transfers ground-generated navigation information to users via the communication satellite. In order to achieve accurate Positioning, Velocity and Time (PVT), the CAPS employs the following strategies to overcome the three main obstacles caused by using the communication satellite: (a) by real-time following-up frequency stabilization to achieve stable frequency; (b) by using a single carrier in the transponder with 36 MHz band-width to gain sufficient power; (c) by incorporating Decommissioned Geostationary Orbit communication satellite (DGEO), barometric pressure and Inclined Geostationary Orbit communication satellite (IGSO) to achieve the 3-D positioning. Furthermore, the abundant transponders available on DGEO can be used to realize the large capacity of communication as well as the integrated navigation and communication. With the communication functions incorporated, five new functions appear in the CAPS: (1) combination of navigation and communication; (2) combination of navigation and high accuracy orbit measurement; (3) combination of navigation message and wide/local area differential processing; (4) combination of the switching of satellites, frequencies and codes; and (5) combination of the navigation message and the barometric altimetry. The CAPS is thereby labelled a PVT5C system of high accuracy. In order to validate the working principle and the performance of the CAPS, a trial system was established in the course of two years at a cost of about 20 million dollars. The trial constellation consists of two GEO satellites located at E87.5° and E110.5°, two DGEOs located at E130° and E142°, as well as barometric altimetry as a virtual satellite. Static and dynamic performance tests were completed for the Eastern, the Western, the Northern, the Southern and the Middle regions of China. The evaluation results are as follows: (1) land static test, plane accuracy range: C/A code, 15~25 m; P code, 5~10 meters; altitude accuracy range, 1~3 m; (2) land dynamic test, plane accuracy range, C/A code, 15~25 m; P code, 8~10 m; (3) velocity accuracy, C/A code, 0.13~0.3 m s−1, P code, 0.15~0.17 m s−1; (4) timing accuracy, C/A code, 160 ns, P code, 13 ns; (5) timing compared accuracy of Two Way Satellite Time and Frequency Transfer (TWSTFT), average accuracy, 0.068 ns; (6) random error of the satellite ranging, 10.7 mm; (7) orbit determination accuracy, better than 2 m. The above stated random error is 1σ error. At present, this system is used as a preliminary operational system and a complete system with 3 GEO, 3 DGEO and 3 IGSO is being established.

In this work, the effects of temperature on the DC and RF characteristics of lateral-diffused metal–oxide–semiconductor (LDMOS) transistors were studied. Devices with different layout structures were fabricated using a 40 V LDMOS process. The temperature coefficients of the threshold voltage and channel mobility are negative and their values are similar for devices with fishbone and ring structures. In addition, we found that both the cutoff frequency ( fT) and the maximum oscillation frequency ( fmax) decrease with increasing temperature. The variations of fT with different temperatures are not only affected by the change in transconductance but also affected by the drain resistance. Finally, the temperature behaviors of S-parameters were measured, and the ring structure showed less S22 variation with different temperatures than the fishbone structure. We extracted the model parameters of the devices to explain this observation. [DOI: 10.1143/JJAP.47.2650]

Electronic and magnetic properties of Fe1-xCoxSi alloys were investigated by using a full-potential linear augmented-plane-wave method based on density functional theory. Electronic structure calculation demonstrates that half-metallic property appears in the Fe-rich region of 0 0.25. The concentration dependence of the magnetic moment of the alloys can be understood by the fixed Fermi level at minority band in Fe-rich region, as well as at the majority band in Co-rich region. In Fe-rich alloys, the electronic structure and the magnetic properties at Fe site depend mainly on the spin-polarization of nearest neighbouring Co atoms, while in Co-rich alloys, these features at Co site arise mainly from the neighbours of Fe atoms.

The DC and RF characteristics of lateral-diffused metal–oxide–semiconductor (LDMOS) transistors with different layout structures were studied. The devices were fabricated using a 0.5 µm LDMOS process. The ring and fishbone structures, which are used widely in power devices, were designed and analyzed. We found that the transconductance, on-resistance, cutoff frequency and maximum oscillation frequency were improved using the ring structure, due to a larger equivalent W/L and lower drain parasitic resistance. In addition, the self-heating effect of LDMOS transistors was also investigated by measuring the pulsed current–voltage (I–V) and pulsed RF characteristics. From the measured results, the ring structure appeared to be a better layout design for RF LDMOS transistors.

The mixing behavior of two fluids in a passive micromixer with Y-type inlet and helical fluid channel, along with herringbone grooves etched on the base of the fluid channel, was studied with computer simulation technique and experiments. The mixing of pure water and acetone solution under different Reynolds numbers and acetone concentrations were investigated. An image inspection method using the variance in contrast of the image gray level as the measurement parameter was adopted to calculate the mixing efficiency distribution. Inspection results show that the mixing efficiency is decreased with the increase of the concentration of the acetone solution, but the mean mixing efficiency around the outlet can reach to a value of 90% even the Reynolds numbers of the fluids were as low as Re = 1, and the best efficiency for the case of Re = 10 is over 98%. The results show that the proposed micromixer is possible applied to the field of biomedical diagnosis.

We discuss the superfluid phase transition of a strongly interacting Fermi gas with unequal (asymmetric) chemical potentials in two pairing hyperfine states, and map out its phase diagram near the BCS-BEC crossover. Our approach includes the fluctuation contributions of {}``preformed Cooper pairs'' to the thermodynamic potential at finite temperature. We show that, below a critical difference in chemical potentials between species, a normal gas is unstable towards the formation of either a finite-momentum paired Fulde-Ferrell-Larkin-Ovchinnikov superconducting phase or a uniform superfluid, depending on the asymmetry and interaction strengths. We determine the value of critical chemical potential mismatch, and find good qualitative agreement with a recent measurement by Zwierlein \textit{et al.} {[}Science \textbf{311}, 492 (2006){]}., 7 pages + 3 figures; To appear in Europhysics Letters

We initially propose a Reggeon-Pomeron exchange model to describe proton-proton elastic scattering at high energies in this short paper. A calculation for total cross section of proton-proton elastic scattering at high energies is performed without any free parameters. Our new finding from this work is that the Reggeon-Pomeron model gives a perfect fit to experimental data of the total cross section at the whole energy region where experimental data exist.

We present a theory for a superfluid Fermi gas near the BCS-BEC crossover, including pairing fluctuation contributions to the free energy similar to that considered by Nozieres and Schmitt-Rink for the normal phase. In the strong coupling limit, our theory is able to recover the Bogoliubov theory of a weakly interacting Bose gas with a molecular scattering length very close to the known exact result. We compare our results with recent Quantum Monte Carlo simulations both for the ground state and at finite temperature. Excellent agreement is found for all interaction strengths where simulation results are available., Comment: 7 pages, 4 figures, published version in Europhysics Letters, a long preprint with details will appear soon

We report improvements to the molecular tagging velocimetry and thermometry (MTV&T) technique for the simultaneous measurement of velocity and temperature fields in fluid flows. A phosphorescent molecule, which can be turned into a long lifetime tracer upon excitation by photons of appropriate wavelength, is used as a tracer for both velocity and temperature measurements. A pulsed laser is used to 'tag' the regions of interest, and those tagged regions are imaged at two successive times within the lifetime of the tracer molecules. The measured Lagrangian displacement of the tagged molecules provides the estimate of the fluid velocity vector. The simultaneous temperature measurement is achieved by taking advantage of the temperature dependence of phosphorescence lifetime, which is estimated from the intensity ratio of the tagged molecules in the two images. In relation to the original molecular tagging thermometry work of Thompson and Maynes (2001 J. Fluid Eng. 123 293–302), the improvements reported here are the use of lifetime imaging as a ratiometric method to enhance the robustness and accuracy of temperature measurements and the extension of the technique to simultaneous whole-field planar mapping of velocity and temperature fields. Compared with other simultaneous velocity and temperature measurement techniques such as combined PIV-LIF (Sakakibara et al 1997 Int. J. Heat Mass Transfer 40 3163–76, Grissino et al 1999 Proc. 3rd Int. Workshop on Particale Image Velocimetry (Santa Barbara, CA, USA, 16–18 September 1999)) and the DPIV/T technique (Park et al 2001 Exp. Fluids 30 327–38), this method accomplishes the same objectives but with a completely molecular-based approach. Because of its molecular nature, issues such as tracking of the flow by the seed particles and the thermal response of the thermal tracer particles are eliminated. In addition, the use of a single molecular tracer and a dual-frame CCD camera provides for a much reduced burden on the instrumentation and experimental set-up. The implementation and application of the new technique are demonstrated by conducting simultaneous velocity and temperature measurements in the wake region of a heated circular cylinder at a Richardson number of 0.36, a value large enough for the buoyancy effects to potentially influence the flow.

In order to solve the current experimental controversy on the existence of the tenser glueball xi(2230), we examine whether the conclusion from Seth's experimental measurement, which rejects existence of xi(2230), is reliable. We claim that the non-observation of the resonance structure by Seth is not a sound ground for rejecting the existence of xi(2230) but it may just indicate that xi(2230) has a broad width. We also study the tensor glueball properties: the mass, spin, and decay width. Our theoretical predictions of the mass and the spin of the xi(2230) using QCD sum rule are about 2.23 GeV and J = 2, respectively. Our theoretical results also evidently show that the xi(2230) must have a total decay width of about 100 MeV, which is much broader than the reported 20 MeV but a small partial decay width of 2 MeV into p (p) over bar decay channel.

2.0 MeV Au+ ions were implanted into different Si substrates with a fluence of 2×1015 ions/cm2 at room temperature with different angles of incidence. Tested Si substrates are amorphized Si, amorphous Si film and crystal Si. The mean projected range, range straggling and lateral spread have been studied by Rutherford backscattering (RBS). The results show that (1) the experimental mean projected range is larger than the value predicted by TRIM (transport of ions in matter) by around 20%; (2) the experimental range straggling and lateral spread deviate significantly from the TRIM predictions; (3) after the correlation between nuclear and electronic stopping is included, the agreement between experimental and calculated values is markedly improved.

Potassium titanyl phosphate (KTiOPO4 or KTP) was implanted with 1.0 MeV Au+ ions to a fluence of 5×1015 ions cm-2 at room temperature under different angles of incidence. The longitudinal and lateral range profiles, diffusion, damage, surface morphology and structure have been studied by Rutherford backscattering (RBS)/channelling, scanning electron microscopy (SEM) and x-ray diffraction. The results show that (1) the experimental mean projected range is larger than the value predicted by TRIM (transport of ions in matter) by about 15%; (2) the experimental range straggling and lateral spread deviate from the TRIM predictions by around 50 and 20%, respectively; (3) the crystal is completely amorphized in the damaged region; (4) the implanted gold in KTiOPO4 is stable against annealing at 700 °C, but diffusion takes place at and above 800 °C; (5) the surface morphology is different for virgin and Au+ implanted KTiOPO4.

The changes in vortical and turbulent structure in the near field (X / D < 3.0) of jet mixing flow caused by a lobed nozzle were investigated experimentally in the present study. The techniques of planar laser induced fluorescence and particle image velocimetry were used to accomplish flow visualization and velocity field measurements. The experimental results showed that, compared with a circular jet flow, lobed jet mixing flow was found to have a shorter laminar region, a smaller scale of the spanwise Kelvin-Helmholtz vortices, earlier appearance of small scale turbulent structures and a larger region of intensive mixing in the near field of the jet mixing flow. The central line velocity decay of the lobed jet mixing flow was also found to be much faster than that in a conventional circular jet. All these indicated that the lobed nozzle provides better mixing performance than does a conventional circular nozzle.

We investigate the electron spin effect on quantum states and magnetoconductance in a magnetic quantum antidot with inhomogeneous distribution of the magnetic field. It is shown that the interaction of the electron spin with the inhomogeneous magnetic field results in further splitting of the energy levels. The predicted value of the splitting is closely related to the angular momentum quantum number and the parameters of the magnetic quantum antidot. Spin-dependent magnetoconductance is very different from that in the case where the spin effect is not included. More and shallower dips appear in the spin-dependent magnetoconductance spectra.

An experimental study was conducted to investigate the effects of the wave-induced base motions experienced by floating wind turbines sited in offshore wind farms on their aeromechanic performance and wake characteristics, in comparison with those of a bottom- fixed wind turbine. The experimental study was performed in a large-scale atmospheric boundary layer (ABL) wind tunnel with a scaled wind turbine model placed in a turbulent boundary layer flow with similar mean and turbulence characteristics as those over a typical offshore wind farm. During the experiments, a scaled wind turbine model was mounted on a translational and rotational stage, which can generate translation and/or rotation motions to simulate the dynamic wave-induced motions (i.e., surge, pitch and heave motions) experienced by floating wind turbines in offshore wind farms. In addition to measuring dynamic wind loadings (both forces and moments)acting on the model turbine, a high-resolution Particle Image Velocity (PIV) system was also used to conduct detailed flow field measurements to characterize the turbine wakes with the turbine base in motion. The detailed flow field measurements were correlated with the dynamic wind load data to elucidate underlying physics for higher total power yield and better durability of floating offshore wind turbines.

We systematically investigate the effect of pressure on the magnetic properties of GdCo2B2 on the basis of alternating current (AC) susceptibility, AC heat capacity and electrical resistivity measurements under pressures up to 2.2 GPa. A detailed magnetic phase diagram under pressure is determined. GdCo2B2 exhibits three anomalies that apparently reflect magnetic phase transitions, respectively, at temperatures T C = 20.5 K, T 1 = 18.0 K and T N = 11.5 K under ambient pressure. Under pressures up to 2.2 GPa, these anomalies are observed to slightly increase at T C and T 1, and they coincide with each other above 1.6 GPa. Conversely, they decrease at T N and disappear under pressures higher than 1.4 GPa. The results indicate that the low-temperature magnetic phases can be easily suppressed by pressure. Moreover, the spin-glass-like behavior of GdCo2B2 is examined in terms of magnetization, aging effect and frequency dependence of AC susceptibility. A separation between the zero-field-cooled (ZFC) and field-cooled (FC) magnetization curves becomes evident at a low magnetic field of 0.001 T. A long-time relaxation behavior is observed at 4 K. The freezing temperature T f increases with frequency increasing.

The properties of the guided modes, including the single-mode conditions and the coupling of different polarized modes in the single-crystal lithium niobate photonic wires, were analyzed in detail. One-dimensional photonic crystal micro-cavities with several different patterns, which could be used as an ultra-compact optical filter, were designed and simulated in order to get high transmission at the resonant wavelength and the best preferment. The designed structure, with the whole size of 6.5 × 0.7 μm2, was fabricated on a single-mode photonic wire. A measured peak transmission of 0.34 at 1400 nm, an extinction ratio of 12.5 dB and a Q factor of 156 were obtained. The measured transmission spectrum was basically consistent with the simulation, although a slight shift of resonant wavelength occurred due to the fabrication errors.

Three-dimensional filtered backprojection uses filters generally specified in the Fourier domain. Implementing these filters by direct sampling in the Fourier domain produces an artifact in the reconstructed images consisting primarily of a DC shift. This artifact is caused by aliasing of the reconstruction filter. The authors have developed a filter construction technique using Fourier domain oversampling, which reduces the artifact. A method to construct the filter efficiently without the need to create and store the entire oversampled filter array is also presented. Quantitative accuracy in filtered backprojection is of particular importance in multiple-pass algorithms used to reconstruct data from cylindrical PET scanners. The authors are able to implement such algorithms without fitting the reprojected views to the scanner data.

We discuss theoretically a robustness of the difference frequency conversion method and demonstrate it by numerical simulation. This technique, borrowed from an analogous scheme of robust population transfer in atomic physics and nuclear magnetic resonance called 'local optimization', can keep the intermediate frequency fixed and make the counterintuitive ordering emerge automatically. Here we show an efficient frequency conversion in two-process three wave mixing (TWM). And because the local optimization method is a well-defined, automated computational procedure, we think it would be very useful in the efficient conversion of complicated multi-process TWM, which is a difficult subject in STIRAP.

In this work, the low-frequency noise (LFN) characteristics of single-gate (SG) and dual-gate (DG) TaN–Al2O3–Si3N4–SiO2–Si (TANOS) nonvolatile memories (NVMs) with multiple nanowire (multi-NW) channel structures and of DG TANOS NVM with a planar structure were investigated. In polycrystalline silicon TANOS NVM, a small wire channel width yielded a low grain boundary trap density (QT), and therefore a low LFN. After Fowler–Nordheim (FN) programming and erasing, the LFN level increments of both SG and DG TANOS NVMs with multi-NW channel structures were observed to be similar but larger than that of the NVM with a planar structure owing to the different areas that were occupied by corner regions. Additionally, the LFN characteristics of the DG TANOS NVM with multi-NW channel structures under FN and 2-bit modulated FN (MFN) operation were investigated and compared.

A new method to perform blind separation of chaotic signals is articulated in this paper, which takes advantage of the underlying features in the phase space for identifying various chaotic sources. Without incorporating any prior information about the source equations, the proposed algorithm can not only separate the mixed signals in just a few iterations, but also outperforms the fast independent component analysis (FastICA) method when noise contamination is considerable.