T-shaped Electrode Research Articles

Multi-Physical Analysis and Optimization in Integrated Lithium Niobate Modulator Using Micro-Structured Electrodes

With the increase in the modulation rate of thin-film lithium niobate (LiNbO3, LN) modulators, the multi-physical field coupling effect between microwaves, light, and heat becomes more significant. In this study, we developed a thin-film LN modulator model using undoped pure LN thin film and T-shaped slow-wave electrodes. Furthermore, we utilized this model to simulate the microwave heating and light heating situations of the modulator. The temperature of the LN modulator was analyzed over time and with different signal frequencies. We also studied the influence of temperature rise on microwave and light signals, and we analyzed the change of S parameters and the Phase Shift of the light signal caused by temperature rise. Finally, we improved the thermodynamic characteristics of the modulator by adding a diamond heat dissipation layer. The diamond was obtained through the Chemical Vapor Deposition (CVD) technique and was a polycrystalline diamond. After adding the diamond heat dissipation layer, the temperature rise of the modulator was significantly improved, and the adverse effects of temperature rise on microwave signals were also significantly reduced.

Novel T-shaped Electrodes for PEM Water Electrolysis and Numerical Evaluation of Three-dimensional Potential Distribution

Novel T-shaped Electrodes for PEM Water Electrolysis and Numerical Evaluation of Three-dimensional Potential Distribution

Performance analysis and design optimization of a compact thermoelectric generator with T-Shaped configuration

In this study, a compact thermoelectric generator (TEG) configuration composed of T-shaped electrodes and connected P–N thermoelectric legs was developed to improve its performance. Based on the 1D self-consistent numerical model, the electrical impedance matching relations and optimal thermoelectric leg sizes for T-shaped TEG were semi-analytically derived, and demonstrated with a high accurate prediction. The comparison between the developed T-shaped and the conventional π-shaped TEGs was conducted, which indicated that the specific output power was greatly increased by 90.1% under the same given thermal conditions. Furthermore, impacts of the coupled thermal-electrical conditions, thermal conditions and geometric parameters on the performance of T-shaped TEG have been studied in detail. Single-parameter and two-parameter geometric optimizations were also discussed. Then, the optimal geometric size could be obtained under the given heat transfer conditions and external electrical loading. Finally, the optimization of geometric parameters for T-shaped TEG was conducted in different heat transfer conditions. Under the constant heat transfer conditions, the maximum power has improved by 21.9%. The novel structure of the T-shaped TEG proposed could be applied in many application scenarios.

High sensitivity MEMS capacitive hydrogen sensor with inverted T-shaped electrode and ring-shaped palladium alloy for fast response and low power consumption

We report a novel palladium (Pd)-based micro electro-mechanical system (MEMS) capacitive hydrogen gas sensor that has an inverted T-shaped electrode and a ring-shaped Pd alloy layer, which enable high sensitivity and low power consumption. Thanks to these structures, deformation of the membrane as a result of hydrogen absorption can be efficiently transduced to capacitance change. The capacitance change of the proposed sensor is found to be three times larger than that of the conventional structure. Prototype sensors were fabricated by a CMOS-compatible surface micromachining process. The proposed sensor offers a broad design window for attaining high sensitivity. Finally, we show that our sensor provides fast response, is hysteresis-free, and has excellent hydrogen selectivity characteristics despite not employing a heater by using PdCuSi metallic glass.

Analysis of defects in externally driven dust-density wavefronts in cogenerated dusty plasma using the time-resolved Hilbert–Huang transform

Analysis of defects in externally driven dust-density wavefronts (DDWs) in cogenerated dusty plasma has been carried out. The DDWs are excited for threshold positive bias through another T-shaped electrode which is placed inbetween two main discharge electrodes. Spatiotemporal evolution of the DDWs reveals a wave defect and non-propagating wave mode in the DDW field. A space-time plot and the time-resolved Hilbert–Huang transform (HHT) were employed to analyze the spatiotemporal wave data at a specific location in the wave field.

A compact 3D-printed interface for coupling open digital microchips with Venturi easy ambient sonic-spray ionization mass spectrometry.

Digital microfluidics (DMF) based on the electrowetting-on-dielectric phenomenon is a convenient way of handling microlitre-volume aliquots of solutions prior to analysis. Although it was shown to be compatible with on-line mass spectrometric detection, due to numerous technical obstacles, the implementation of DMF in conjunction with MS is still beyond the reach of many analytical laboratories. Here we present a facile method for coupling open DMF microchips to mass spectrometers using Venturi easy ambient sonic-spray ionization operated at atmospheric pressure. The proposed interface comprises a 3D-printed body that can easily be "clipped" at the inlet of a standard mass spectrometer. The accessory features all the necessary connections for an open-architecture DMF microchip with T-shaped electrode arrangement, thermostatting of the microchip, purification of air (to prevent accidental contamination of the microchip), a Venturi pump, and two microfluidic pumps to facilitate transfer of samples and reagents onto the microchip. The system also incorporates a touch-screen panel and remote control for user-friendly operation. It is based on the use of popular open-source electronic modules, and can readily be assembled at low expense.

Discrete 3D T-Shaped Electrode Arrays for Moving Liquid by AC Electro-Osmosis

A novel 3D discrete T-shaped electrode array, fabricated by PolymMUMPs, is presented for pumping microscale liquid utilizing AC electro-osmosis (ACEO). Both the theoretical and experimental work has been carried out to evaluate the new design concept. A 3D finite element model of a unit cell incorporating a pair of electrodes is created to simulate pump performance. The new design is prototyped using the PolyMUMPs process and the experimental evaluation of its performance is conducted with saline solution at three different voltages. The maximum velocity obtained from the tracing particles at 30μm above the bottom of the channel was 90μm/s, 130μm/s and 200μm/s for a voltage of 6Vpp, 8Vpp and 10Vpp respectively.

Laser direct patterning of the T-shaped ITO electrode for high-efficiency alternative current plasma display panels

The laser direct patterning technique is one of the new methods of direct etching process to replace the conventional photolithography. In this experiment, a Q-switched diode-pumped Nd:YVO 4 ( λ = 1064 nm) laser was used to produce the indium–tin oxide (ITO) patterns with a complex T-shaped structure on glass substrate. The results showed that the overlapping rate of laser beam had a major effect on the quality of the edge of the ITO electrode. When the overlapping rate was about 75%, it was possible to obtain optimum linearity in the edge of patterned ITO electrode. By using the optimum conditions of 75% overlapping rate, 500 mm/s scanning speed, and 40 kHz repetition rate, an alternative current plasma display panels (AC PDPs) with T-shaped ITO electrode was fabricated and characterized. The discharging results showed that the AC PDPs with the laser ablated T-shaped ITO electrode had a better discharging characteristics compared to the conventional sample with wet-etched stripe-type ITO electrode.

고효율 플라즈마 디스플레이 패널을 위한 T-형 ITO 전극의 레이저 직접 패터닝시 레이저 스캔 속도의 영향

Laser direct patterning is one of new methods which are able to replace a conventional photolithography. In order reduce the fabrication cost and to improve the luminous efficiency of AC plasma display panels (PDPs), in this experiment, a Q-switched Nd:<TEX>$YVO_4$</TEX> laser was used to fabricate T-shaped indium tin oxide (ITO) display electrodes. For the laser beam scanning speed from 100 mm/sec to 800 mm/sec, T-shaped ITO patterns were clearly obtained and investigated. The experimental results showed that the optimized T-shaped ITO electrode was obtained when the lasers scanning speed was 300 mm/s.

Plasma-augmented combustion behaviour in methanol

High-current discharge is studied between two electrodes where the filling medium is a mixture of methanol and air. Combustion is ignited by a 52 kJ discharge between two T-shaped electrodes. The combustion device consists of a 52 kJ capacitor bank, a discharge and combustion chamber and diagnostic systems. Current disruption has been observed at the moment of a change between the capacitive and inductive discharges. This has been referred to plasma expansion and termination when there is no voltage between the electrodes. The disruption time increases with an increase in the charging voltage. The kinetic pressure of combustion has shown three different behaviours. The first type is similar to partial fuel normal combustion. The second type is complete normal combustion. The third type is fast plasma combustion which results when an exponential pressure decay due to the heat transport process, very low heat losses and the short rise time of the kinetic pressure is obtained.

Ex vivo electroporation as a potent new strategy for nonviral gene transfer into autologous vein grafts

Gene transfer to vein grafts has therapeutic potential to prevent late graft failure; however, certain issues, including efficacy and safety, have hindered the clinical application of this treatment modality. Here, we report the successful and efficient gene transfer of plasmid DNA via ex vivo electroporation into veins as well as into vein grafts. Two approaches were used: one involved transluminal in situ gene transfer using a T-shaped electrode (the "Lu" method), and the other was an adventitial ex vivo approach using an electroporation cuvette followed by vein grafting (the "Ad" method). The Lu method was carried out at 10 V, with optimal gene transfer efficiency in the in situ jugular veins of rabbits, and transgene expression was observed primarily in endothelial cells. However, when these veins were grafted into the arterial circulation, no luciferase activity was detected; this effect was probably due to the elimination of the gene-transferred cells as a result of endothelial denudation. In contrast, optimal and satisfactory gene transfer was obtained with the vein grafts subjected to the Ad method at 30 V, and transgene expression was seen primarily in adventitial fibroblasts. Gene transfer of endothelial nitric oxide synthase cDNA to the vein graft via the Ad method successfully limited the extent of intimal hyperplasia, even under hyperlipidemic conditions, at 4 wk after grafting. We thus propose that the Ad method via ex vivo electroporation may provide a novel, safe, and clinically available technique for nonviral gene transfer to sufficiently prevent late graft failure.

Three-dimensional fluid simulation of a plasma display panel cell

In order to understand the discharge characteristics in an alternating current plasma display panel (ac PDP) and optimize it further, a three-dimensional fluid code (FL3P) has been developed. Using this simulator, various three-dimensional features of discharges are investigated in the sustain mode of PDP. First, the striations of wall charge are observed at both the anode and cathode side. Second, the local efficiency is obtained as a function of position. It is mainly divided into the anode region and the cathode region and highest near the anode center. Finally, the effects of various three-dimensional parameters are studied. As one of the examples showing the effect of electrode shaping, the discharge characteristics of a T-shaped electrode cell are compared with those of a conventional cell. The phosphor on barrier ribs contributes to over 44% of the total luminance, but barrier ribs themselves do not play an important role in the overall discharge efficiency. Address electrode width is not always proportional to the size of the discharge because of the wall loss of the particles to barrier ribs.

Three-dimensional fluid simulation of an AC-PDP cell

Using a three-dimensional fluid model, we present top-views of AC-PDP cells with three different electrode shapes-a conventional electrode cell, a T-shaped electrode cell, and an asymmetric electrode cell. Figures include the contours of consumed power and photon generation power that are time averaged over the half period and space averaged over the direction that is not shown.

Successful and optimized in vivo gene transfer to rabbit carotid artery mediated by electronic pulse.

Several gene transfer methods, including viral or nonviral vehicles have been developed, however, efficacy, safety or handling continue to present problems. We developed a nonviral and plasmid-based method for arterial gene transfer by in vivo electronic pulse, using a newly designed T-shaped electrode. Using rabbit carotid arteries, we first optimized gene transfer efficiency, and firefly luciferase gene transfer via electronic pulse under 20 voltage (the pulse length: P(on)time 20 ms, the pulse interval: P(off) time 80 ms, number of pulse: 10 times) showed the highest gene expression. Exogenous gene expression was detectable for at least up to 14 days. Electroporation-mediated gene transfer of E. coli lacZ with nuclear localizing signal revealed successful gene transfer to luminal endothelial cells and to medial cells. Histological damage was recognized as the voltage was increased but neointima formation 4 weeks after gene transfer was not induced. In vivo electroporation-mediated arterial gene transfer is readily facilitated, is safe and may prove to be an alternative form of gene transfer to the vasculature.

A novel self-aligned T-shaped gate process for deep submicron Si MOSFET's fabrication

T-shaped gate electrode is highly desired for high-speed FET fabrication since it can significantly reduce the gate resistance. In this study, we propose and demonstrate a self-aligned method of forming T-shaped gate which is suitable for ULSI Si-MOSFET's fabrication. This method employs CMP planarization, BOE selective etching and poly-Si sidewall spacer techniques to form the T-shaped poly-Si gate structure. Ti and Co silicidation were also incorporated to demonstrate the effectiveness of this process. Our experimental results indicate that the proposed process not only reduces the parasitic gate resistance, but also improves the thermal stability of the gate structure.

Fabrication of p+-Gate InAs-Channel HEMT Based on InP

We have successfully fabricated a p+- n junction gate InGaAs/InAlAs high electron mobility transistor (HEMT) with a thin InAs layer inserted in the InGaAs channel. An intrinsic transconductance of over 400 mS/mm and maximum drain current of 250 mA/mm were obtained in a 1 µ m gate length device with relatively thick gate-to-channel barrier of 375 Å. We have also applied the present fabrication method to 0.25 µ m gate length device using electron beam lithography and wet chemical etching, verifying the decent dc operation with reduced gate leakage current. T-shaped gate electrode was shown to be successfully fabricated for the basic investigation of HEMT for high frequency operation.

Self-aligned InP/InGaAs HBTs using T-shaped emitter electrodes

Self-aligned InP/InGaAs HBTs using T-shaped emitter electrodes

Permanent pervenous transseptal atrial pacing: Canine experiments and a clinical case

Permanent atrial pacing has lain dormant during the last decade because pervenous electrodes usually fail to maintain endocardial contact, and epicardial electrodes require a thoracotomy for implantation. The major advantage is the preservation of synchronized atrioventricular (A-V) contractility. Development of a technique for attaching pacing electrodes to the endocardium through the venous system by an extrathoracic maneuver may permit achievement of reliable long-term atrial pacing pervenously. Canine experiments led to the first clinical application of atrial pacing by way of a transseptal electrode. A Ross needle was modified to carry a 10 mm T-shaped electrode tip across the atrial septum. An intraluminal stylet was used to eject the electrode into the left atrium. The electrode tip was then pulled snugly against the atrial septal endocardium. The hearts of 10 dogs were paced successfully for 3 to 12 months with average thresholds of 6 ma. At autopsy, various degrees of fibrosis constituted the sole pathologic finding. The heart of a 78 year old man with carotid sinus syncope was paced in August 1972, with use of a permanent transseptal atrial electrode and a unipolar pulse generator. The initial threshold was 2 ma and the pacemaker impulse-QRS interval was 180 msec. Consistent long-term atrial pacing may be achieved by attaching a pervenous electrode to the interatrial septum.

Pervenous Atrial Pacing by Fixed Electrode

To the Editor.— Permanent atrial pacing has lain dormant during the last decade because pervenous unattached electrodes usually fail to maintain contact with the endocardium, and epicardial electrodes require a thoracotomy for implantation. Reliable endocardial pacing can be achieved, however, by attaching a pervenous electrode to the interatrial septum by an extrathoracic maneuver using a long needle apparatus introduced through the venous system. A Ross transseptal needle used for left atrial catheterization has been modified to carry a T-shaped electrode tip and conducting wire across the atrial septum, as shown in Fig 1. This new technique has been applied successfully in two dozen large dogs with very few pathological findings observed at the electrode fixation site on postmortem examination at six and ten months after implantation. The first clinical application of pacing the heart by attaching an endocardial electrode to the interatrial septum is reported here. Examination of a 78-year-old