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Hydraulic steel gates are the core adjustment mechanism for water conservancy projects, the safety of which is related to the safety of the entire water conservancy project. In this study, the issue of flow-induced vibration under the influence of pulsing water pressure when the deep-hole plane steel gate construction is partially opened is investigated using a numerical calculation approach of CFD–CSD coupling. The time-history pulsating pressure loads of each part are first determined by tracking the upstream, bottom, and downstream pulsating water pressure loads under partially open operation conditions of the gate. The impact of the water in front of the gate on the natural vibration mode and frequency of the gate is then investigated based on the analysis of the dry/wet modes of the gate structure. Additionally, the hydrodynamic load is applied to the finite element model of the gate structure while taking into account the fluid–structure coupling effect, and the results of the gate flow-induced vibration response are obtained. Three typical local opening relative openings are chosen, with the operating state of the design water head (Hs = 70 m) of a deep-hole plane steel gate as an example. According to the analysis’s findings, the gate’s natural vibration frequency is greatly lowered under the influence of the water in front of it, and its amplitude increases by 50%. The pressure value pressing on the gate changes dynamically as it is partially opened and discharged. The maximum dynamic displacement value and the maximum dynamic stress value of the gate both appear in the middle and lower part of the gate under the condition of partial opening, and both occur when the relative opening is e/H = 0.125. The maximum displacement value is 3.43 mm, and the maximum stress value is 161 MPa. The maximum dynamic displacement and dynamic stress of each gate component steadily decrease with an increase in the relative openness. The gate dynamic response analysis approach described in this research can serve as a guide for hydraulic engineering design.

The monolithic integration structure of the AlGaN/InGaN/GaN−based high electron mobility transistor (HEMT) and light−emitting diode (LED) is attractive in LED lighting and visible light communication (VLC) systems owing to the reduction in parasitic elements by removing metal interconnections. Due to the band−offset and polarization effect, inserting a certain thickness in the InGaN layer into the traditional AlGaN/GaN single heterostructure increases the density of 2DEG to nearly twice the original. At the same time, inserting the InGaN quantum well layer can also improve the luminous efficiency of LED. In this paper, the physical models of two−dimensional electron gas (2DEG) densities and the threshold voltage of AlGaN/InGaN/GaN HEMTs are established and verified with experimental results from the literature. According to the calculation results, the two−dimensional electron gas (2DEG) density in the AlGaN/InGaN/GaN HEMT is 1.47 × 1013 cm−2, and the two−dimensional hole gas (2DHG) density is 0.55 × 1013 cm−2, when Al% = 0.2, In% = 0.1, dAlGaN = 20 nm. In addition, a physical model for the radiative recombination rate in the monolithic integration structure of HEMT−LED is proposed. This work provides a design guideline for AlGaN/InGaN/GaN HEMT and its application in visible light communication systems.

Micro-LED is a new technology applied in the display field, which has the advantages of self-illumination, low power consumption, high brightness, long life and ultra-high resolution, and has broad application prospects. Using MOS devices to drive micro-LED can enable each unit to have its own drive, thus improving the yield and reducing the subsequent repair processes. In this paper, Sentaurus TCAD simulation software is used to design and simulate NMOS/PMOS devices and their driving circuits. For the first time, CMOS inverters are used to directly drive Micro-LED. Three kinds of driving circuits are compared and analyzed according to their simulation results in output characteristics and transient characteristics. In terms of switching characteristics caused by output characteristics, a CMOS inverter driving a micro-LED circuit has no problems of incomplete turn-off and has greater advantages. In the switching characteristics aspect caused by transient characteristics, PMOS driving a micro-LED circuit has the shortest turn-on time and greater advantages. When compared with a micro-LED driven by an access current-limiting resistor, a micro-LED driven by a direct drive has a smaller on-time value and greater advantages.

An ultra-low turn-on voltage (VT) Γ-shaped anode AlGaN/GaN Schottky barrier diode (GA-SBD) is proposed via modeling and simulation for the first time, in which a Γ-shaped anode consists of a metal-2DEG junction together with a metal-AlGaN junction beside a shallowly recessed MIS field plate (MFP). An analytic forward current-voltage model matching the simulation results well is presented where an ultra-low VT of 0.08 V is obtained. The turn-on and blocking mechanisms are investigated to reveal the GA-SBD’s great potential for applications of highly efficient power ICs.

Physical models for threshold voltage and drain saturation current of AlGaN/GaN MIS-FinFETs have been established and verified by TCAD simulation to provide guidelines for the GaN MIS-FinFETs-based designs. The depletion effect on the two dimensional electron gases (2DEG) channel by sidewall fin gate is modeled based on the numerical solutions of Poisson equation with proper boundary conditions. The conduction band at the 2DEG zone lifted above the Fermi level by the gate bias is modeled for getting the threshold voltage. The device saturation current, comprising 2DEG channel current and sidewall channel current, as a function of fin width has also been modeled. The influences of device design parameters on the threshold voltage and saturation current are analyzed by the proposed models with verification.

Different from the signals of amplitude and phase lag in piezoresponse force microscopy (PFM) and piezoresponse force spectroscopy (PFS), the signals of the contact resonance frequency (f0) have not been clearly interpreted. Due to the complexity of the tip–sample system at the nanoscale, the relevant models and mechanisms were continuously improved in the past decades. The variation of f0 has been reported in a few previous studies, but the physical meaning of the unique variation in ferroelectric materials still needs to be investigated. Due to the imperfect tip–sample contact, the existence of a dielectric gap and screening charges causes the discontinuity in the conduction band. The evolution of the electrostatic force during the PFS measurements is significantly affected by the tip-induced ferroelectric domain evolution, resulting in the variation of the effective contact stiffness (k*) and f0. By involving the screening effect and tunneling effect in this model, the anomalies of the on-field f0 and off-field f0 can be well explained, respectively.

A good magnetic field sensor should exhibit high sensitivity, low power consumption, and low output offset to accurately detect small fields. In this work, the high sensitivity in magnetoresistance variation (ΔR) is achieved by the AlGaN/GaN fin-shaped high electron mobility structure, in comparison to that of planar structures. A physical based analysis is presented to describe the influence of the fin width dimension on the ΔR dependency under magnetic fields. The sensitivity is expressed as a function of geometric parameters, electron mobility, and two-dimensional electron sheet density, with relaxation of polarization, shoulder density distribution, and sidewall trapped charges considered. Devices were fabricated, and a high sensitivity is observed in laboratory measurements on devices at narrower fin widths. At the fin width of 50 nm, the measured device has a sensitivity of 0.76 Ω/μΤ2 at the magnetic flux of 85 μΤ. The sensor's power consumption is as low as 48 μW, and the minimum magnetic flux detectable is at 20 μΤ.

In this letter, the suppression of dynamic on-state resistance (RON) degradation for faster dynamic RON recovery is achieved by the multimesa-channel (MMC) structure in AlGaN/GaN high electron mobility transistors. The measurement results are discussed with the physical mechanisms investigated. The initial transient RON degradation is reduced in the MMC structure, resulting from the lower peak electric field around the drain-side gate edge in the trigate structure compared to that in a planar device. The faster dynamic RON recovery in MMC devices is attributed to the quick emission of electrons at sidewall traps of shallower energy levels. The energy levels of dominant traps at the sidewall and top interfaces are found to be 0.26 eV and 0.37 eV below the conduction band edge, respectively, verified by Technology Computer Aided Design simulations in agreement with the measurement data.

In this paper, a single-stage LED driver is proposed for a street lighting system. Two boost circuits that share a single inductor are formed by integrating the switches of a half-bridge $LLC$ resonant converter. Both boost circuits operate in the boundary conduction mode, which realizes a power-factor correction function. Because the input voltage of the LED driver is divided by two capacitors, the bus voltage is considerably reduced to almost the input peak voltage, rendering the novel single-stage LED driver to work suitably under high-input-voltage conditions. The soft-switching characteristics of the half-bridge $LLC$ resonant circuit are not affected by the integration of the switches; thus, the converter has a low cost and a high efficiency. A 100-W prototype was developed, and the efficiency was determined to be as high as 91.1% in a full-load state under a 220-V ac input.

This study assessed the extent to which social sexism affects Chinese women's perception and evaluation of other women's performance. A sample of 100 college women was selected in a top university in Beijing, China, and was asked to read six scholastic essays and then evaluate the quality of the essays and competence of the authors. Male and female names were randomly assigned as authors of the essays, and the respondents were blind to the arrangement. Results showed that the essays assumed to be written by male authors did not receive higher scores than those assumed to be written by female authors on quality or competence items. Sexism is not marked among these highly educated young women.