Enhancement of water self-diffusion at super-hydrophilic surface with ordered water
It has been well acknowledged that molecular water structures at the interface play an important role in the surface properties, such as wetting behavior or surface frictions. Using molecular dynamics simulation, we show that the water self-diffusion on the top of the first ordered water layer can be enhanced near a super-hydrophilic solid surface. This is attributed to the fewer number of hydrogen bonds between the first ordered water layer and water molecules above this layer, where the ordered water structures induce much slower relaxation behavior of water dipole and longer lifetime of hydrogen bonds formed within the first layer.
Multiple Darboux-Bäcklund transformations via truncated Painlevé expansion and Lie point symmetry approach
For a given truncated Painlevé expansion of an arbitrary nonlinear Painlevé integrable system, the residue with respect to the singularity manifold is known as a nonlocal symmetry, called the residual symmetry, which is proved to be localized to Lie point symmetries for suitable prolonged systems. Taking the Korteweg-de Vries equation as an example, the n-th binary Darboux-Bäcklund transformation is re-obtained by the Lie point symmetry approach accompanied by the localization of the n-fold residual symmetries.
Distance-based formation tracking control of multi-agent systems with double-integrator dynamics
Stochastic evolutionary public goods game with first and second order costly punishments in finite populations
Frequency response range of terahertz pulse coherent detection based on THz-induced time-resolved luminescence quenching
Growth mode of helium crystal near dislocations in titanium
Monogamy quantum correlation near the quantum phase transitions in the two-dimensional XY spin systems
Quantum speed-up capacity in different types of quantum channels for two-qubit open systems
Quantum estimation of detection efficiency with no-knowledge quantum feedback
Classical-driving-assisted coherence dynamics and its conservation
Demonstration of quantum permutation parity determine algorithm in a superconducting qutrit Hot!
A quantum algorithm provides a new way in solving certain computing problems and usually faster than classical algorithms. Here we report an implementation of a quantum algorithm to determine the parity of permutation in a single three-dimensional (3D) superconducting transmon qutrit system. The experiment shows the capacity to speed up in a qutrit, which can also be extended to a multi-level system for solving high-dimensional permutation parity determination problem.
Electronic and magnetic properties of semihydrogenated, fully hydrogenated monolayer and bilayer MoN2 sheets
Topologically protected edge gap solitons of interacting Bosons in one-dimensional superlattices
General series expression of eddy-current impedance for coil placed above multi-layer plate conductor
This paper presents a closed expression of the layered-plate factor used to calculate the coil eddy-current impedance over the multi-layer plate conductor. By using this expression, the general series of eddy-current impedance can be written directly without solving the undetermined constant equations. The series expression is easy to use for theoretical analysis and programming. Experimental results show that calculated values and measured values are in agreement. As an application, when the bottom layer of the layered plate is a non-ferromagnetic thin layer conductor and the product of the thickness and conductivity of the layer remains unchanged, using the layered-plate factor expression proposed in this paper, it can be theoretically predicted that the eddy-current impedance curves corresponding to different thin layer thickness values will coincide.
Dynamic characteristics in an external-cavity multi-quantum-well laser
The heat and work of quantum thermodynamic processes with quantum coherence
Energy is often partitioned into heat and work by two independent paths corresponding to the change in the eigenenergies or the probability distributions of a quantum system. The discrepancies of the heat and work for various quantum thermodynamic processes have not been well characterized in literature. Here we show how the work in quantum machines is differentially related to the isochoric, isothermal, and adiabatic processes. We prove that the energy exchanges during the quantum isochoric and isothermal processes are simply depending on the change in the eigenenergies or the probability distributions. However, for a time-dependent system in a non-adiabatic quantum evolution, the transitions between the different quantum states representing the quantum coherence can affect the essential thermodynamic properties, and thus the general definitions of the heat and work should be clarified with respect to the microscopic generic time-dependent system. By integrating the coherence effects in the exactly-solvable dynamics of quantum-spin precession, the internal energy is rigorously transferred as the work in the thermodynamic adiabatic process. The present study demonstrates that the quantum adiabatic process is sufficient but not necessary for the thermodynamic adiabatic process.
Superconducting membrane mechanical oscillator based on vacuum-gap capacitor
Using the diluted S1813 UV photoresist as a sacrificial layer, we successfully fabricate a superconducting suspended parallel-plate capacitor, in which the top layer of aluminum film acts as a membrane mechanical resonator. Together with a superconducting octagonal spiral inductor, this parallel-plate capacitor constitutes a superconducting microwave resonator. At mK temperature, the transmission characteristic and spectrum of the microwave resonator are measured. Sideband frequencies caused by the vibration of the membrane mechanical resonator are clearly demonstrated. By down-converting with a mixer, the dependence of fundamental frequency and its harmonics on the input microwave power are clearly demonstrated, which is consistent with the numerical simulation.
Cryogenic amplifier with low input-referred voltage noise calibrated by shot noise measurement
A low-noise cryogenic amplifier for the bandwidth from 100 kHz to 2 MHz with commercially available components is presented. The amplifier is mounted on the cold finger of our home-made liquid helium dipstick. The input impedance of the amplifier is 2 kΩ. The input-referred voltage noise of the amplifier at approximately 2 MHz is around 1 nV/√Hz. We demonstrate the performance of the amplifier by measuring shot noise on the Al/AlOx/Al tunneling junction with resistance about 17 kΩ at liquid helium temperature.
Baseline optimization for scalar magnetometer array and its application in magnetic target localization
Determination of static dipole polarizabilities of Yb atom
We determine the static values of the scalar and tensor dipole polarizabilities of the ground, 6s6p3P0o, and 6s6p3P1o states of the Yb atom. These results can be useful in many experiments undertaken using this atom. We employed a combined configuration interaction (CI) method and a second-order many-body perturbation theory (MBPT) to evaluate energies and electric dipole (E1) matrix elements of many low-lying excited states of the above atom. These values are compared with the other available theoretical calculations and experimental values. By combining these E1 matrix elements with the experimental excitation energies, we estimate the dominant valence correlation contributions to the dipole polarizabilities of the above states. The core contribution is obtained from the finite field approach. We also compare these values with the other theoretical results as there are no precise experimental values that are available for these properties.
Structure, stability, catalytic activity, and polarizabilities of small iridium clusters
Effect of nickel segregation on CuΣ9 grain boundary undergone shear deformations
Single and double Auger decay of 4f-ionized mercury including cascade and direct processes
Single (SA) and double (DA) Auger decay including cascade and direct processes are investigated for Hg 4f-1 with multiconfiguration Dirac-Fock method and two-step approaches, i.e., knockout and shakeoff mechanisms. Due to the computational effort, only the major transitions are considered to describe the SA and DA decays for the Hg+ ions with complex electronic configurations. In order to estimate the Auger transition energies and amplitudes, the reference configuration sets producing the configuration state functions are carefully chosen for balancing electron correlations among the successive singly, doubly and triply ionized mercury. The Auger rates and electron spectra, DA probabilities as well as the populations of the final Hg3+ states are obtained. Our results well explain the recent experimental data about the 4f hole states of Hg[Palaudoux J et al., Phys. Rev. A 91 012513 (2015)], and could provide guidance for further studies on complex atoms. Particularly for the DA decay, the contributions of the direct processes, which are neglected in their calculations, are found to be important, accounting for as high as about 38% and 34% of the total DA decays for the 4f7/2-1 and 4f5/2-1, respectively.
Demonstration of superadiabatic population transfer in superconducting qubit
Enhanced ionization of vibrational hot carbon disulfide molecules in strong femtosecond laser fields
By using a heated molecular beam in combination with a time-of-flight mass spectrometer, we experimentally study the ionization of vibrational-hot carbon disulfide (CS2) molecules irradiated by a linearly polarized 800-nm 50-fs strong laser field. The ion yields are measured in a laser intensity range of 7.0×1012 W/cm2-1.5×1014 W/cm2 at different molecular temperatures of up to 1400 K. Enhanced ionization yield is observed for vibrationally excited CS2 molecules. The results show that the enhancement decreases as the laser intensity increases, and exhibits non-monotonical dependence on the molecular temperature. According to the calculated potential energy curves of the neutral and ionic electronic states of CS2, as well as the theoretical models of molecular strong-field ionization available in the literature, we discuss the mechanism of the enhanced ionization of vibrational-hot molecules. It is indicated that the enhanced ionization could be attributed to both the reduced ionization potential with vibrational excitation and the Frank-Condon factors between the neutral and ionic electronic states. Our study paves the way to understanding the effect of nuclear motion on the strong-field ionization of molecules, which would give a further insight into theoretical and experimental investigations on the interaction of polyatomic molecules with strong laser fields.
Dynamics of the CH4+O(3P)→CH3(ν=0)+OH(ν'=0) reaction
The dynamics of the ground-state reaction of CH4+O(3P) → CH3(ν=0) +OH(ν'=0) have attracted a great deal of attention both theoretically and experimentally. This rapid communication represents extensive quasi-classical trajectory calculations of the vibrational distributions on a unique full-dimensional ab initio potential energy surface for the title reaction, at the collision energy of relevance to previous crossed molecular beam experiments. The surface is constructed using the all electrons coupled-cluster singles and doubles approach plus quasi-perturbative triple excitations with optimized basis sets. A modified Shepard interpolation method is also employed for the construction. Good agreement between our calculations and the available experimental results has been achieved, opening the door for accurate dynamics on this surface.
Investigations of the dielectronic recombination of phosphorus-like tin at CSRm
The electron-ion recombination for phosphorus-like 112Sn35+ has been measured at the main cooler storage ring of the Heavy Ion Research Facility in Lanzhou, China, employing an electron-ion merged-beams technique. The absolute total recombination rate coefficients for electron-ion collision energies from 0 eV-14 eV are presented. Theoretical calculations of recombination rate coefficients were performed using the Flexible Atomic Code to compare with the experimental results. The contributions of dielectronic recombination and trielectronic recombination on the experimental rate coefficients have been identified with the help of the theoretical calculation. The present results show that the trielectronic recombination has a substantial contribution to the measured electron-ion recombination spectrum of 112Sn35+. Although a reasonable agreement is found between the experimental and theoretical results the precise calculation of the electron-ion recombination rate coefficients for M-shell ions is still challengeable for the current theory.
Overrun phenomenon and neutron yield in Coulomb explosion of deuterated alkane clusters driven by intense laser field
Optimization of endcap trap for single-ion manipulation
Potential distribution is an important characteristic for evaluating the performance of an ion trap. Here, we analyze and optimize the potential distribution of an endcap ion trap for single-ion trapping.We obtain an optimal endcap radius of 225 μm-250 μm, endcap-shield gap of~250 μm, and inter-endcap distance of 540 μm-590 μm. The simulation method for analysis can also be applied to other ion traps, which is useful for improving the design and assembly of ion traps.
Propagation of acoustic waves in a fluid-filled pipe with periodic elastic Helmholtz resonators
Reversed rotation of limit cycle oscillation and dynamics of low-intermediate-high confinement transition
The dynamics of the confinement transition from L mode to H mode (LH) is investigated in detail theoretically via the extended three-wave coupling model describing the interaction of turbulence and zonal flow (ZF) for the first time. Thereinto, turbulence is divided into a positive-frequency (PF) wave and a negative-frequency (NF) one, and the gradient of pressure is added as the auxiliary energy for the system. The LH confinement transition is observed for a sufficiently high input energy. Moreover, it is found that the rotation direction of the limit cycle oscillation (LCO) of PF wave and pressure gradient is reversed during the transition. The mechanism is illustrated by exploring the wave phases. The results presented here provide a new insight into the analysis of the LH transition, which is helpful for the experiments on the fusion devices.
Measurements of argon metastable density using the tunable diode laser absorption spectroscopy in Ar and Ar/O2
Densities of Ar metastable states 1s5 and 1s3 are measured by using the tunable diode laser absorption spectroscopy (TDLAS) in Ar and Ar/O2 mixture dual-frequency capacitively coupled plasma (DF-CCP). We investigate the effects of high-frequency (HF, 60 MHz) power, low-frequency (LF, 2 MHz) power, and working pressure on the density of Ar metastable states for three different gas components (0%, 5%, and 10% oxygen mixed in argon). The dependence of Ar metastable state density on the oxygen content is also studied at different working pressures. It is found that densities of Ar metastable states in discharges with different gas components exhibit different behaviors as HF power increases. With the increase of HF power, the metastable density increases rapidly at the initial stage, and then tends to be saturated at a higher HF power. With a small fraction (5% or 10%) of oxygen added in argon plasma, a similar change of the Ar metastable density with HF power can be observed, but the metastable density is saturated at a higher HF power than in the pure argon discharge. In the DF-CCP, the metastable density is found to be higher than in a single frequency discharge, and has weak dependence on LF power. As working pressure increases, the metastable state density first increases and then decreases, and the pressure value, at which the density maximum occurs, decreases with oxygen content increasing. Besides, adding a small fraction of oxygen into argon plasma will significantly dwindle the metastable state density as a result of quenching loss by oxygen molecules.
Fractional Stokes-Einstein relation in TIP5P water at high temperatures
Jamming of packings of frictionless particles with and without shear
By minimizing the enthalpy of packings of frictionless particles, we obtain jammed solids at desired pressures and hence investigate the jamming transition with and without shear. Typical scaling relations of the jamming transition are recovered in both cases. In contrast to systems without shear, shear-driven jamming transition occurs at a higher packing fraction and the jammed solids are more rigid with an anisotropic force network. Furthermore, by introducing the macro-friction coefficient, we propose an explanation of the packing fraction gap between sheared and non-sheared systems at fixed pressure.
Li adsorption on monolayer and bilayer MoS2 as an ideal substrate for hydrogen storage
Effects of temperature and point defects on the stability of C15 Laves phase in iron: A molecular dynamics investigation
Mechanisms of atmospheric neutron-induced single event upsets in nanometric SOI and bulk SRAM devices based on experiment-verified simulation tool
In this paper, a simulation tool named the neutron-induced single event effect predictive platform (NSEEP2) is proposed to reveal the mechanism of atmospheric neutron-induced single event effect (SEE) in an electronic device, based on heavy-ion data and Monte-Carlo neutron transport simulation. The detailed metallization architecture and sensitive volume topology of a nanometric static random access memory (SRAM) device can be considered to calculate the real-time soft error rate (RTSER) in the applied environment accurately. The validity of this tool is verified by real-time experimental results. In addition, based on the NSEEP2, RTSERs of 90 nm-32 nm silicon on insulator (SOI) and bulk SRAM device under various ambient conditions are predicted and analyzed to evaluate the neutron SEE sensitivity and reveal the underlying mechanism. It is found that as the feature size shrinks, the change trends of neutron SEE sensitivity of bulk and SOI technologies are opposite, which can be attributed to the different MBU performances. The RTSER of bulk technology is always 2.8-64 times higher than that of SOI technology, depending on the technology node, solar activity, and flight height.
Non-monotonic dependence of current upon i-width in silicon p-i-n diodes
Pressure-induced enhancement of optoelectronic properties in PtS2
PtS2, which is one of the group-10 transition metal dichalcogenides, attracts increasing attention due to its extraordinary properties under external modulations as predicted by theory, such as tunable bandgap and indirect-to-direct gap transition under strain; however, these properties have not been verified experimentally. Here we report the first experimental exploration of its optoelectronic properties under external pressure. We find that the photocurrent is weakly pressure-dependent below 3 GPa but increases significantly in the pressure range of 3 GPa-4 GPa, with a maximum~6 times higher than that at ambient pressure. X-ray diffraction data shows that no structural phase transition can be observed up to 26.8 GPa, which indicates a stable lattice structure of PtS2 under high pressure. This is further supported by our Raman measurements with an observation of linear blue-shifts of the two Raman-active modes to 6.4 GPa. The pressure-enhanced photocurrent is related to the indirect-to-direct/quasi-direct bandgap transition under pressure, resembling the gap behavior under compression strain as predicted theoretically.
Phase transition and near-zero thermal expansion of Zr0.5Hf0.5VPO7
Explicit forms of zero modes in symmetric interacting Kitaev chain without and with dimerization
The fermionic and bosonic zero modes of the one-dimensional (1D) interacting Kitaev chain at the symmetric point are unveiled. The many-body structures of the Majorana zero modes in the topological region are given explicitly by carrying out a perturbation expansion up to infinite order. We also give the analytic expressions of the bosonic zero modes in the topologically trivial phase. Our results are generalized to the hybrid fermion system comprised of the interacting Kitaev model and the Su-Schrieffer-Heeger (SSH) model, in which we show that these two types of zero modes can coexist in a certain region of its phase diagram.
The structural, electronic, and optical properties of organic-inorganic mixed halide perovskites CH3NH3Pb(I1-y Xy)3 (X=Cl, Br)
Magnetic interactions in a proposed diluted magnetic semiconductor (Ba1-xKx)(Zn1-yMny)2P2
By using first-principles electronic structure calculations, we have studied the magnetic interactions in a proposed BaZn2P2-based diluted magnetic semiconductor (DMS). For a typical compound Ba(Zn0.944Mn0.056)2P2 with only spin doping, due to the superexchange interaction between Mn atoms and the lack of itinerant carriers, the short-range antiferromagnetic coupling dominates. Partially substituting K atoms for Ba atoms, which introduces itinerant hole carriers into the p orbitals of P atoms so as to link distant Mn moments with the spin-polarized hole carriers via the p-d hybridization between P and Mn atoms, is very crucial for the appearance of ferromagnetism in the compound. Furthermore, applying hydrostatic pressure first enhances and then decreases the ferromagnetic coupling in (Ba0.75K0.25)(Zn0.944Mn0.056)2P2 at a turning point around 15 GPa, which results from the combined effects of the pressure-induced variations of electron delocalization and p-d hybridization. Compared with the BaZn2As2-based DMS, the substitution of P for As can modulate the magnetic coupling effectively. Both the results for BaZn2P2-based and BaZn2As2-based DMSs demonstrate that the robust antiferromagnetic (AFM) coupling between the nearest Mn-Mn pairs bridged by anions is harmful to improving the performance of these Ⅱ-Ⅱ-V based DMS materials.
Complex alloying effect on thermoelectric transport properties of Cu2Ge(Se1-xTex)3
To enhance the thermoelectric performance of Cu2GeSe3, a series of Te-alloyed samples Cu2Ge(Se1-xTex)3 are synthesized and investigated in this work. It is found that the lattice thermal conductivity is reduced drastically for x=0.1 sample, which may be attributed to the point defects introduced by alloying. However, for samples with x ≥ 0.2, the lattice thermal conductivity increases with increasing x, which is related to a less distorted structure. The structure evolution, together with the change in carrier concentration, also leads to a systemically change in electrical properties. Finally, a zT of 0.55@750 K is obtained for the sample with x=0.3, about 62% higher than that for the pristine sample.
How to characterize capacitance of organic optoelectronic devices accurately
Electrical controllable spin valves in a zigzag silicene nanoribbon ferromagnetic junction
Room-temperature large photoinduced magnetoresistance in semi-insulating gallium arsenide-based device
Enhanced photoresponse performance in Ga/Ga2O3 nanocomposite solar-blind ultraviolet photodetectors
In the present work, we explore the solar-blind ultraviolet (UV) photodetectors (PDs) with enhanced photoresponse, fabricated on Ga/Ga2O3 nanocomposite films. Through pre-burying metal Ga layers and thermally post-annealing the laminated Ga2O3/Ga/Ga2O3 structures, Ga/Ga2O3 nanocomposite films incorporated with Ga nanospheres are obtained. For the prototype PD, it is found that the photocurrent and photoresponsivity will first increase and then decrease monotonically with the thickness of the pre-buried Ga layer increasing. Each of all PDs shows a spectrum response peak at 260 nm, demonstrating the ability to detect solar-blind UV light. Adjustable photoresponse enhancement factors are achieved by means of the surface plasmon in the nanocomposite films. The PD with a 20 nm thick Ga interlayer exhibits the best solar-blind UV photoresponse characteristics with an extremely low dark current of 8.52 pA at 10-V bias, a very high light-to-dark ratio of~8×105, a large photoresponsivity of 2.85 A/W at 15-V bias, and a maximum enhancement factor of~220. Our research provides a simple and practical route to high performance solar-blind UV PDs and potential applications in the field of optoelectronics.
Resonant surface plasmons of a metal nanosphere treated as propagating surface plasmons
Improved performance of Au nanocrystal nonvolatile memory by N2-plasma treatment on HfO2 blocking layer
Enhanced transient photovoltaic characteristics of core-shell ZnSe/ZnS/L-Cys quantum-dot-sensitized TiO2 thin-film
Enhancement of off-state characteristics in junctionless field effect transistor using a field plate
Superconductivity of bilayer titanium/indium thin film grown on SiO2/Si (001)
Current-induced synchronized magnetization reversal of two-body Stoner particles with dipolar interaction
Voltage control of magnetization switching and dynamics
Transition intensity calculation of Yb: YAG
Variable angle spectroscopic ellipsometry and its applications in determining optical constants of chalcogenide glasses in infrared
Free-standing, curled and partially reduced graphene oxide network as sulfur host for high-performance lithium-sulfur batteries
Lithium-sulfur (Li-S) batteries have received more and more attention because of higher specific capacity and energy density of sulfur than current lithium-ion batteries. However, the low electrical conductivity of sulfur and its discharge product, and also the high dissolution of polysulfides restrict the Li-S battery practical applications. To improve their performances, in this work, we fabricate a novel free-standing, curled and partially reduced graphene oxide (CPrGO for short) network and combine it with sulfur to form a CPrGO-S composite as a cathode for Li-S battery. With sulfur content of 60 wt%, the free-standing CPrGO-S composite network delievers an initial capacity of 988.9 mAh·g-1. After 200 cycles, it shows a stable capacity of 841.4 mAh·g-1 at 0.2 C, retaining about 85% of the initial value. The high electrochemical performance demonstrates that the CPrGO-S network has great potential applications in energy storage system. Such improved properties can be ascribed to the unique free-standing and continous CPrGO-S network which has high specific surface area and good electrical conductivity. In addition, oxygen-containing groups on the partially reduced graphene oxide are beneficial to preventing the polysulfides from dissolving into electrolyte and can mitigate the “shuttle effect”.
Wider frequency domain for negative refraction index in a quantized composite right-left handed transmission line
In situ growth of different numbers of gold nanoparticles on MoS2 with enhanced electrocatalytic activity for hydrogen evolution reaction
Producing hydrogen through a hydrogen evolution reaction (HER) by splitting water at the suitable overpotential is a great alternative to solving the problems of environmental pollution and the energy crisis. Molybdenum sulfide (MoS2) has attracted extensive attention as one of the most promising catalytic materials for HER. In this work, we design a facile method to in situ grow gold nanoparticles (AuNPs) on MoS2. Different numbers of AuNPs with MoS2 are used to find the best catalytic activity. Due to the larger active surface area and higher conductivity of the Au-MoS2 composites, all the Au-MoS2 composites exhibit more enhanced HER electroactivity than pure MoS2. In brief, the new material architecture exhibits optimized HER activity with a low onset overpotential of 0.12 V, low Tafel slope of 0.163 V·dec-1, and an excellent stability in acidic solution.
Effect of substrate curvature on thickness distribution of polydimethylsiloxane thin film in spin coating process
Tuning hybrid liquid/solid electrolytes by lowering Li salt concentration for lithium batteries Hot!
Hybrid liquid/solid electrolytes (HLSEs) consisting of conventional organic liquid electrolyte (LE), polyacrylonitrile (PAN), and ceramic lithium ion conductor Li1.5Al0.5Ge1.5(PO4)3 (LAGP) are proposed and investigated. The HLSE has a high ionic conductivity of over 2.25×10-3 S/cm at 25℃, and an extended electrochemical window of up to 4.8 V versus Li/Li+. The Li|HLSE|Li symmetric cells and Li|HLSE|LiFePO4 cells exhibit small interfacial area specific resistances (ASRs) comparable to that of LE while much smaller than that of ceramic LAGP electrolyte, and excellent performance at room temperature. Bis(trifluoromethane sulfonimide) salt in HLSE significantly affects the properties and electrochemical behaviors. Side reactions can be effectively suppressed by lowering the concentration of Li salt. It is a feasible strategy for pursuing the high energy density batteries with higher safety.
Electrical field-driven ripening profiles of colloidal suspensions
Electrorheological (ER) fluid is a type of smart fluid whose shear yield stress relies on the external electrical field strength. The transition of ER fluid microstructure driven by the electrical field is the reason why viscosity changes. Experimentally, the transparent electrodes are used to investigate the column size distribution where an external electric field is applied to a colloidal suspension, i.e., ER fluid is increased. The coarsening profile of ER suspensions is strongly related to electrical field strength, but it is insensitive to particle size. In addition, in a low field range the shear stress corresponding to the mean column diameter is studied and they are found to satisfy a power law. However, this dependence is invalid when the field strength surpasses a threshold value.
Tunable circularly-polarized turnstile-junction mode converter for high-power microwave applications
Characterization of barrier-tunable radio-frequency-SQUID for Maxwell's demon experiment
Compact wide stopband superconducting bandpass filter using modified spiral resonators with interdigital structure
In this study, we propose a novel resonator that is composed of a modified spiral with an embedded interdigital capacitor. A large ratio of the first spurious frequency to the fundamental resonant frequency is obtained, which is suitable for the design of filters with wide stopbands, and the circuit size is considerably reduced by embedding the interdigital structure in the spiral. For demonstration, a compact four-pole high temperature superconducting (HTS) filter with a center frequency of 568 MHz is designed and fabricated on double-sided YBCO film with a size of 11.4 mm×8.0 mm. The filter measurement shows excellent performance with an out-of-band rejection level better than 60.9 dB up to 3863 MHz.
Compact high-order quint-band superconducting band-pass filter
Degradation of current-voltage and low frequency noise characteristics under negative bias illumination stress in InZnO thin film transistors
Physics-based analysis and simulation model of electromagnetic interference induced soft logic upset in CMOS inverter
Integration of a field-effect-transistor terahertz detector with a diagonal horn antenna
Efficient coupling of terahertz electromagnetic wave with the active region in a terahertz detector is required to enhance the optical sensitivity. In this work, we demonstrate direct integration of a field-effect-transistor (FET) terahertz detector chip at the waveguide port of a horn antenna. Although the integration without a proper backshot is rather preliminary, the noise-equivalent power is greatly reduced from 2.7 nW/Hz1/2 for the bare detector chip to 76 pW/Hz1/2 at 340 GHz. The enhancement factor of about 30 is confirmed by simulations revealing the effective increase in the energy flux density seen by the detector. The simulation further confirms the frequency response of the horn antenna and the on-chip antennas. A design with the detector chip fully embedded within a waveguide cavity could be made to further enhance the coupling efficiency.
Interaction between human telomeric G-quadruplexes characterized by single molecule magnetic tweezers
Detection of finger interruptions in silicon solar cells using photoluminescence imaging
Since publication, it has been brought to the attention of the Editorial Office of Chinese Physics B that parts of this paper showed strong similarities to the following article (including one equation, some analyses, the motivation and the conclusion) without citation: “Detection of Finger Interruptions in Silicon Solar Cells Using Line Scan Photoluminescence Imaging,” IEEE Journal of Photovoltaics, 2017, vol. 7, No. 6, pp. 1496-1502. Following our investigation, this article has been retracted by the Editorial Office of Chinese Physics B.
Finger interruptions are common problems in screen printed solar cells, resulting in poor performance in efficiency because of high effective series resistance. Electroluminescence (EL) imaging is typically used to identify interrupted fingers. In this paper, we demonstrate an alternative method based on photoluminescence (PL) imaging to identify local series resistance defects, with a particular focus on finger interruptions. Ability to detect finger interruptions by using PL imaging under current extraction is analyzed and verified. The influences of external bias control and illumination intensity on PL images are then studied in detail. Finally, in comparison with EL imaging, the using of PL imaging to identify finger interruptions possesses the prominent advantages:in PL images, regions affected by interrupted fingers show higher luminescence intensity, while regions affected by recombination defects show lower luminescence intensity. This inverse signal contrast allows PL imaging to more accurately identify the defect types.