Movable Gate Research Articles

Imaging Nanomechanical Vibrations and Manipulating Parametric Mode Coupling via Scanning Microwave Microscopy.

In this study, we present a novel platform based on scanning microwave microscopy for manipulating and detecting tiny vibrations of nanoelectromechanical resonators using a single metallic tip. The tip is placed on the top of a grounded silicon nitride membrane, acting as a movable top gate of the coupled resonator. We demonstrate its ability to map mechanical modes and investigate mechanical damping effects in a capacitive coupling scheme, based on its spatial resolution. We also manipulate the energy transfer coherently between the mode of the scanning tip and the underlying silicon nitride membrane, via parametric coupling. Typical features of optomechanics, such as anti-damping and electromechanically induced transparency, have been observed. Since the microwave optomechanical technology is fully compatible with quantum electronics and very low temperature conditions, it should provide a powerful tool for studying phonon tunnelling between two spatially separated vibrating elements, which could potentially be applied to quantum sensing.

Liquid-infused interfacial floatable porous membrane as movable gate for ultrafast immiscible oil/water separation.

Liquid separation methods are widely used in industrial and everyday applications, however, their applicability is often constrained by low efficiency, membrane fouling, and poor energy efficiency. Herein, a conceptually novel liquid-infused interfacial floatable porous membrane (LIIFPM) system for high-performance oil/water separation is proposed. The system functions by allowing a liquid to wet and fill a superamphiphilic porous membrane, thereby creating a stable liquid-infused interface that floats at the oil/water interface and prevents the passage of immiscible liquids. The lower-layer liquid can outflow directly, while the flow of the upper-layer liquid is stopped by the membrane. Remarkably, the efficiency of the LIIFPM system is independent of the membrane pore size, enabling ultrafast immiscible oil/water separation in an energy-saving and antifouling manner.

Alternative weir design using circular crested type and vlughter type energy dissipators on the Yeh Empas Longstorage in Tabanan Regency

Climate change affects seasonal changes throughout the world, including in Indonesia a tropical country that experiences rainy and dry seasons with the possibility of facing drought or flood disasters. The long storage construction has an objective to overcome the problem of water availability during the dry and rainy seasons. The Yeh Empas long storage is one of the construction weirs with rubber as a barrier and a movable gate in the Yeh Empas River as a reservoir for raw water for Tabanan Regency. The utilization of movable gates and rubber weir bodies has disadvantages in terms of cost and construction time due to the ordering time. The objective of the current study is to design an alternative weir using circular crested type and Vlughter type energy dissipators without replacing the long storage function. The weir was designed by implementing a 100-year return period flood discharge of 163.29 m3/dt. The design result depicts the dimensions of weir elements consisting of the crest radius, the crest height, the energy dissipator length, the upstream slope, the downstream slope, and the effective width is 1.00 m, 3.30 m, 5.70 m, 2:3, 1:1, and 26.31 m, respectively.

Experimental investigation of sediment movement as a result of homogeneous earth-fill dam overtopping break over a simplified urban area

When an earth-fill dam breaks, dam body sediment and water flow simultaneously move to downstream area causing devastation. Dam break studies in the literature have concentrated mostly on the water flow part while ignoring the sediment movement by designing the dam body as a movable metal gate. This study, however, is the first one experimentally investigating flow and sediment transport due to an earth-fill dam break by constructing the dam body from sediment. Sediment propagation as a result of homogenous earth-fill dam overtopping break was experimentally studied in a laboratory flume of 18.4 m long and 2.0 m wide, and 0.88 m in height in the Hydraulics Laboratory of Izmir Katip Celebi University, Izmir, Turkey. Downstream section right after the dam body was designed as a smooth bed and rough bed. The rough bed, resembling a simplified urban area, was created by using thirteen 10 × 10 × 10 cm sized concrete blocks. The dam body was constructed as homogenous with uniform material having D50 = 0.441 mm. The earth-fill dam body was built using the standard compression methods; each layer of sediment with a thickness of 10 cm was laid in layers, and the body was prepared with a crest width of 10 cm, a transverse base width of 200 cm, a longitudinal base width of 202 cm and height of 60 cm with upstream and downstream slopes of 1:1.6. The water level behind the dam was gradually raised until it overtopped the crest level. A pre-breach was formed at the top of the dam to trigger the break. During each dam break event, water depths were measured by three ULS-40D level meter sensors at different locations, and the final sediment bathymetry map was generated using the ULS-40D Probes at 10 × 10 cm grids. The results showed that, in both smooth and rough downstream bed cases, the dam body eventually collapsed while a great portion of it was carried away by the flood flow. The sediment spreading occurred all over the downstream area, showing significant non-uniform variation in thickness both longitudinally and transversely, especially in the simulated urban area. All the residential areas, while breaking in motion, were submerged under the muddy flow. Some blocks were almost submerged while sediment heights reached half level of some blocks at the end of the experiment. Sediment heights were higher in the urban area.

A Risk Approach to the Management for the Pre-defueled Phase in the Decommissioning Transition Stage

We discuss the specific risk significance in the extended pre-defueled (PD) phase of the decommissioning process, particularly if spent fuels are still in the core due to the low-power and shutdown refueling plant operating state (POS). The issue of full-core discharge capability after permanent shutdown during the PD phase motivated this study on the evolution of system risks using a reference plant design of the two-unit/BWR-4/Mark-I. The effects of the reactor core and the spent fuel pool (SFP) on the incorporative risks are explored. The probabilistic risk assessment methodology, including the technical elements, is systematically developed by defining two primary configurations from the internal event analysis under the models 30, 60, 180, 365, and 942 days after permanent shutdown, respectively. The movable refueling gate between the reactor core and the SFP, as well as the residual heat removal (RHR) system, have been subjected to two sensitivity studies on system configurations in order to examine the induced impacts by the refueling gate and cooling systems. MELCOR, a realistic thermal-hydraulic code, is utilized to determine the decay heat levels and the success criteria after shutdown. The two operator tasks are assumed to be independent in the situation of decreasing decay heat after shutdown and a long time available for human actions. In addition, the WinNUPRA software package is used for the fuel uncovery sequence quantification. Plant-centered loss-of-offsite power (LOOP), flow diversion loss-of-coolant accidents (LOCAs) to the suppression pool via the RHR system, switchyard-centered LOOPs, and LOCAs in the connected systems via the RHR, have proven to be the most significant initiating events for the configurations. When compared to the low-power and shutdown refueling POS, the realistic quantification results in terms of fuel uncovery frequencies and the evolution of the risk profile for the basic and sensitivity configurations meet the expectations under the PD-phase condition of low-decay heat levels.

A MEMS Micro Force Sensor Based on A Laterally Movable Gate Field-Effect Transistor (LMGFET) with A Novel Decoupling Sandwich Structure

This paper presents the development of a novel micro force sensor based on a laterally movable gate field-effect transistor (LMGFET). A precise electrical model is proposed for the performance evaluation of small-scale LMGFET devices and exhibits improved accuracy in comparison with previous models. A novel sandwich structure consisting of a gold cross-axis decoupling gate array layer and two soft photoresistive SU-8 layers is utilized. With the proposed dual-differential sensing configuration, the output current of the LMGFET lateral operation under vertical interference is largely eliminated, and the relative output error of the proposed sensor decreases from 4.53% (traditional differential configuration) to 0.01%. A practicable fabrication process is also developed and simulated for the proposed sensor. The proposed LMGFET-based force sensor exhibits a sensitivity of 4.65 µA·nN−1, which is comparable with vertically movable gate field-effect transistor (VMGFET) devices, but has an improved nonlinearity of 0.78% and a larger measurement range of ±5.10 µN. These analyses provide a comprehensive design optimization of the electrical and structural parameters of LMGFET devices and demonstrate the proposed sensor’s excellent force-sensing potential for biomedical micromanipulation applications.

The thermal analysis of pre-defueled operation for decommissioning of a BWR4 reactor

After the operating license of the Nuclear Power Plant (NPP) has expired, a lack of storage capacity of the spent fuel pool (SFP) may occur when the dry storage facilities are not ready. As a result, the fuel of the last cycle will remain in the reactor vessel. When the NPP is under pre-defueled operation mode, it means the vessel head is removed, interconnecting with the upper cavity and SFP via movable gate. Hence, the reactor vessel, upper cavity, and SFP can be treated as an integrated system.This study has developed a MELCOR2.1/SNAP model to analyze the thermal response under the recirculation loop occurring break. There are two decay power conditions in this study: limited condition (7 days after shutdown) and realistic condition (942 days after shutdown). Based on the results of the recirculation line break accident under the limited condition with low-pressure coolant injection (LPCI), the core integrity may be challenged. And the realistic condition is less harsh than the limited condition; the core can be adequately cooled following a loss of coolant at the recirculation line break.

An experimental investigation of dam-break induced flood waves for different density fluids

The present study aims to investigate the effect of various fluids on dam-break flow propagation in a rectangular and horizontal channel under dry bed conditions. Laboratory experiments were carried out to produce dam-break flood waves in a tank by the sudden release of a movable gate that divided the tank into a reservoir and a downstream channel. In these experiments, three different fluids were used as Newtonian fluids in the reservoir: normal water, sunflower oil, and salt water. A digital image processing technique was adopted for the experimental characterization of the dam-break waves. Instantaneous free surface profiles of the dam-break flow were captured by a high-speed camera. Free-surface profiles for different times and time evolution of the flow depths at four selected locations were determined. The types of fluids had an effect on the results due to their specific characteristics such as density and viscosity. Furthermore, numerical simulation of the problem was performed by Reynolds-averaged Navier-Stokes (RANS) and Volume of Fluid (VOF) based software Flow-3D. When the experimental data were compared with the numerical simulation results, there was good agreement for the elapsed time and selected measuring locations.

The design characteristic of the hot blast valve and its effect on blast furnace temperature during the switching period of the air heaters

The article considers the structure and characteristics of a hot blast valve which is traditionally installed on air heaters of blast furnaces of domestic metallurgical plants. The hot blast valve connects the heated air heater of the blast furnace to the hot blast pipeline, that is, it transfers the air heater from the heating mode to the blowing mode. It is a water-cooled gate valve with a round bore and a semicircular movable gate, which is moved by an electric actuator. The main characteristics of any valve are its constructive, throughput and working characteristics. Constructive characteristics establish the dependence of the flow area on the movement of its gate, and the working characteristics establish the dependence of the flow rate of the substance on the movement of its gate under operating conditions. The cold blast valve is installed at the inlet of the air heater and during the period of its opening the cold blast is supplied to both air heaters, cooled and hot. As this takes place, there is no blast pressure drop between the air heaters valves, since we have a parallel connection of the blast pipelines with fully open hot blast valves of the cooled and heated air heater. Under such operating conditions of the air heater valves, the design characteristic of the valve becomes its working characteristics and its area determines the flow rate of the blast through it. In this regard, in order to analyze the effect of the valve operation on the hot blast temperature during the air heater switching period, it is necessary to find its design characteristic. For this, an analytical method was used to find a mathematical expression for this characteristic, an analysis was made of the change in the flow rate of blast through the cold blast valve when it was opened and closed during the air heater switching period. In this case, in the process of opening the cold blast valve of the heated air heater, the ratio of the amount of blast, which passes through the heated and cooled air heater, changes, which causes an increase in the blast temperature and reaching a certain maximum of it. The availability of a mathematical description of the working characteristic of the cold blast valve makes it possible to further analyze the temperature change during the air heater switching period and prevent its uncontrolled change

High‐Resolution Monolithic Integrated Tribotronic InGaZnO Thin‐Film Transistor Array for Tactile Detection

AbstractTactile detection is a crucial technology in many fields, such as electronic skin, touch screen control, human prostheses, and screen fingerprint identification. Tribotronics has demonstrated active mechanosensation from external mechanical stimuli, which greatly enriches the sensing mechanisms of tactile detection. In this work, a monolithic integrated indium‐gallium‐zinc‐oxide (InGaZnO or IGZO) thin‐film transistor (TFT) array is developed for high‐resolution tactile detection. By using the conventional semiconductor fabrication processes, each IGZO TFT cell in the array shows uniform electrical performance. In addition, the drain–source current can be individually tuned by the electrostatic potential generated by the contact electrification between a movable gate and the gate dielectric. The monolithic integrated array displays a relatively high resolution of 12 pixels per inch and can realize a millimeter‐level tactile perception and motion tracking. This work presents a facile and viable strategy toward micro/nano‐scale tribotronics, which can realize high‐resolution and large‐scale tactile detection.

The Design and Analysis of a Novel Micro Force Sensor Based on Depletion Type Movable Gate Field Effect Transistor

A novel micro force sensor based on depletion type vertically movable gate array field effect transistor (VMGAFET) was developed with cross-axis decoupling structure and eight gate arrays. This novel sensor is able to detect ultra-low force and exhibit high measuring sensitivity. An accurate electrical model was then proposed and compared with a long channel model, which is better adopted in small-sized devices to predict the electrical performance of this sensor. We also developed a mechanical model for the micro force sensor. Finite element method simulations were conducted, and the results were in accordance with the theoretical ones. Then, a feasible fabrication process was illustrated for the proposed sensor. The measuring sensitivity and nonlinearity of the micro force sensor with the proposed structure and dimension parameters are $12.528~\mu \text{A}$ /nN and <1.35%, respectively. These theoretical analyses provide insights into the design of depletion type VMAGFET-based sensor and other kinds of devices based on movable gate field effect transistor or with similar movable structures.

Performance Optimization of Pressure Sensor Based on Suspended Gate MOSFET

This paper examines the modeling, simulation and optimization of CMOS–MEMS integrated pressure sensor based on suspended gate MOSFET. The pressure Sensor consists of a square poly silicone suspended membrane, which is the movable gate of the NMOS. This NMOS is designed using 2 μm CMOS technology. The mathematical model describing the complete behaviour of the PSFET pressure sensor has been described. Finite element method (FEA) based COMSOL Multiphysics is utilized for the simulation of pressure sensor. The simulation results show that, the output current of the pressure sensor varied from 355 to 3624 μA as the pressure changed from zero to 180 kPa and high pressure sensitivity of 15,18μA/kPa. Furthermore, this study emphasizes on the influence of the channel geometric parameters on the aforementioned characteristics to optimize the sensor performance.

Imaging quantum dot formation in MoS2 nanostructures

Among two-dimensional materials, semiconducting ultrathin sheets of MoS2 are promising for nanoelectronics. We show how a scanning probe microscope (SPM) can be used to image the flow of electrons in a MoS2 Hall bar sample at 4.2 K allowing us to understand device physics at the nanoscale. The SPM tip acts as a movable gate and capacitively couples the SPM tip to the device below. By measuring the change in device conductance as the tip is raster scanned across the sample, spatial maps of the device conductance can be obtained. We present images showing the characteristic ‘bullseye’ pattern of Coulomb blockade conductance rings around a quantum dot formed in a narrow contact as the carrier density is depleted with a backgate. These images show that multiple dots are created by the disorder potential in MoS2. From these SPM images, we estimate the size and position of these quantum dots using a capacitive model.

A novel uncooled thermal imaging sensor using MEMS transistor

In this paper a new uncooled thermal imaging sensor using MEMS transistor with movable gate is presented. The novelty of this work is making moveable polysilicon gate by two minder bi-materials arms on silicon substrate using MEMS technology. The arms are deflected with absorbed infrared temperature from objects, and move the gate plate. By changing air gap between gate and Si channel, the drain current of transistor will be changed. The geometrical parameters are obtained using analysis of the structure. A FEM simulation was performed using COMSOL Multiphysics software to verify the validity. This structure has many advantages; including compatibility with CMOS fabrication process, high sensitivity, low power consumption, no need signal amplification, ability to miniaturization of pixel size, much more than other techniques that used until now.

Numerical investigation of the gate motion effect on a dam break flow

The effects of a moving gate on dam break flow experiments are numerically considered in this paper. The dam break flow process is modelled by a sudden gate release. A Constrained Interpolation Profile (CIP)-based model is employed to solve the Navier-Stokes equations with the free surface boundary condition to deal with the water-air-gate interactions. In addition, the VOF-type THINC/SW method is used to capture the free surface. The movable gate is simulated by an immersed boundary, and a gate motion formula is proposed from existing experimental data and applied in the dam break flow computations. The difference between the water profile and pressure domain with/without gate motion is examined. The dam breaks with different gate motions are discussed as well. The numerical results show that the proposed gate motion formula correlates well with the numerical modelling, and the gate motion has a significant influence in the water collapse process and cannot be neglected in the study of dam break.

Probing weak localization in chemical vapor deposition graphene wide constriction using scanning gate microscopy

Low-temperature scanning gate microscopy (LT-SGM) studies of graphene allow one to obtain important spatial information regarding coherent transport such as weak localization (WL) and universal conductance fluctuations. Although fascinating LT-SGM results on pristine graphene prepared by mechanical exfoliation have been reported in the literature, there appears to be a dearth of LT-SGM results on chemical vapor deposition (CVD)-grown graphene whose large scale and flexible substrate transferability make it an ideal candidate for coherent electronic applications. To this end, we have performed LT-SGM studies on CVD-grown graphene wide constriction (0.8 μm), which can be readily prepared by cost-effective optical lithography fully compatible with those in wafer foundry, in the WL regime. We find that the movable local gate can sensitively modulate the total conductance of the CVD graphene constriction possibly due to the intrinsic grain boundaries and merged domains, a great advantage for applications in coherent electronics. Moreover, such a conductance modulation by LT-SGM provides an additional, approximately magnetic-field-independent probe for studying coherent transport such as WL in graphene and spatial conductance variation.

津波・高潮減災のための技術開発

A devlopment of the movable flap gate type breakwater, which is based on a steel flap gate in hydraulic gates with a number of adoption results, is reaching the final stage of demonstration tests in the sea.The flap gate type breakwater usually lies down on a seabed and rises up through a sea surface with buoyancy when tsunami or storm surge occurs. In past studies reflected viewpoints of a large number of specialists, it has been confirmed that the flap gate type breakwater has capabilities against tsunamis. This paper describes the characteristics of the flap gate type breakwater, the expansion of utilizations in seawalls except breakwaters for tsunami and storm surge reduction.

Micro-accelerometer Based on Vertically Movable Gate Field Effect Transistor.

A vertically movable gate field effect transistor (VMGFET) is proposed and demonstrated for a micro-accelerometer application. The VMGFET using air gap as an insulator layer allows the gate to move on the substrate vertically by external forces. Finite element analysis is used to simulate mechanical behaviors of the designed structure. For the simulation, the ground acceleration spectrum of the 1952 Kern County Earthquake is employed to investigate the structural integrity of the sensor in vibration. Based on the simulation, a prototype VMGFET accelerometer is fabricated from silicon on insulator wafer. According to current–voltage characteristics of the prototype VMGFET, the threshold voltage is measured to be 2.32 V, which determines the effective charge density and the mutual transconductance of 1.545×10−8 C cm−2 and 6.59 mA V−1, respectively. The device sensitivity is 9.36–9.42 mV g−1 in the low frequency, and the first natural frequency is found to be 1230 Hz. The profile smoothness of the sensed signal is in 3 dB range up to 1 kHz.

개량형 가동보에 적용하기 위한 하이브리드 강판/GFRP 패널 게이트의 강판게이트 표면형상에 따른 휨 및 계면 부착 특성 평가

The purpose of this study was to improved the durability of a improved movable weir by replacing the improved movable weir's metal gate with a hybrid steel/glass fiber reinforced polymer composites panel gate. Because the metal gate of a improved movable weir is always in contact with water, its service life is shortened by corrosion. This study made four type of hybrid steel/glass fiber reinforced polymer composites panel gate with different steel gate surface deformation (control, sand blast, scratch and hole), flexural. Fracture properties tests were performed depending on the steel gate surface deformation. According to the test results, the flexural behavior, flexural strength and fracture properties of hybrid steel/glass fiber reinforced polymer composites panel gate was affected by the steel panel gate surface deformation. Also, the sand blast type hybrid steel/glass fiber reinforced polymer composites panel gate shows vastly superior flexural and fracture performance compared to other types.

Characterization of a vertically movable gate field effect transistor using a silicon-on-insulator wafer

The vertically movable gate field effect transistor (VMGFET) is a FET-based sensing element, whose gate moves in a vertical direction over the channel. A VMGFET gate covers the region between source and drain. A 1 μm thick air layer separates the gate and the substrate of the VMGFET. A novel fabrication process to form a VMGFET using a silicon-on-insulator (SOI) wafer provides minimal internal stress of the gate structure. The enhancement-type n-channel VMGFET is fabricated with the threshold voltage of 2.32 V in steady state. A non-inverting amplifier is designed and integrated on a printable circuit board (PCB) to characterize device sensitivity and mechanical properties. The VMGFET is mechanically coupled to a speaker membrane to apply mechanical vibration. The oscillated drain current of FET are monitored and sampled with NI LabVIEW. The frequency of the output signal correlates with that of the input stimulus. The resonance frequency of the fabricated VMGFET is measured to be 1.11 kHz. The device sensitivity linearly increases by 0.106 mV/g Hz in the range of 150 Hz and 1 kHz.