Double Tunnel Research Articles

Adjusting amplitude of the stored optical solitons by inter-dot tunneling coupling in triple quantum dot molecules

We study the propagation properties of a probe field in an aligned asymmetric triple quantum dot molecule with both sides inter-dot tunneling coupling effect. It is shown that the probe field can form optical soliton due to the destructive quantum interference induced by the quantum inter-dot tunneling coupling effect. Interestingly, these optical solitons can be stored and retrieved by adjusting single or double inter-dot tunneling coupling effect, different from that light memory in the ultra-cold atom system. Furthermore, we also find that the amplitude of the stored optical soliton can be adjusted by the strength of the single or double inter-dot tunneling coupling. It is possible to improve the stability and the fidelity of the optical information in the process of the storage and retrieval in semiconductor quantum dots devices.

Settlement Prediction of Double Line Shield Tunnel in Upper Soft and Lower Hard Stratas

Settlement Prediction of Double Line Shield Tunnel in Upper Soft and Lower Hard Stratas

Design and analysis of a double gate SiGe/Si tunnel FET with unique inner-gate engineering

An inner-gate engineered double gate heterostructure tunnel field effect transistor (SiGe/Si-IGTFET) has been presented. The inner-gate is grown at the center of the Si0.6Ge0.4/Si TFET, followed by a thin HfO2 dielectric layer. The drain current performance of the suggested device has been investigated comprehensively to discover its efficacy. The device provides much-lower ambipolarity (by 6 decades) compared to heterostructure TFET with a similar dimension. The SiGe/Si-IGTFET device has also shown higher immunity against short channel effects such as drain induced barrier lowering and gate induced drain leakage current (I GIDL). To examine the impact of inner-gate, various DC parameters such as ambipolar current (I amb), on current (I on), I on/I amb current ratio, average subthreshold swing (SS), surface potential, and electric field have been considered. The device offers a much improved current ratio (I on/I amb) of 1.78 × 1012 with an average SS of 23 mV decade−1 by optimizing the position and dielectric material of the inner-gate. The simulation of the suggested device is carried out using a 2D Silvaco Technology Computer-Aided Design (TCAD) device simulator.

Source material valuation of charge plasma based DG-TFET for RFIC applications

This paper seeks to present a comprehensive analysis to check the viability of four different source materials in a charge plasma-based double gate tunnel field effect transistor (CP-DGTFET) as RF/microwave systems components. This work aims to provide a comparative study of the electrical and analog parameters of three devices (labeled as D-II, D-III, D-IV) with Si0.5Ge0.5, Ge, Mg2Si as the source material with a conventional Si source homojunction CP-DGTFET (referred as D-I). In addition, linearity and distortion are investigated. The selection of the source material illustrates the effect on the band structure at heterojunctions, as a combined effect of low bandgap and electron affinities of the material used. Results obtained through numerical simulations show that the device D-IV with Mg2Si source shows excellent performance parameters with maximum I ON (4.6 × 10−3 A µm−1) and minimum V th (0.26 V). Also, the switching ratio (1013) and SS (10.89 mV/decade) offered by D-IV is the best among all four devices investigated. Various linearity FOM’s viz. transconductance and its higher order derivatives (g m , g m2 , g m3), higher order voltage intercept points (V IP2 , V IP3), third-order intercept input power, third-order intermodulation distortion, 1 dB compression point, 2nd and 3rd order harmonic distortion, and total harmonic distortions (THD) have also been examined. All of this research was carried out using the Atlas Silvaco simulation tool. This study reveals that the Mg2Si source CP-DGTFET is best suited for high-frequency, low-power and high linearity applications in modern communication systems.

Double-Tunnel Technique Was Similar to Single-Tunnel Technique in Clinical, Imaging and Functional Outcomes for Medial Patellofemoral Ligament Reconstruction: A Randomized Clinical Trial

This study aimed to compare the clinical, functional, and imaging outcomes of single-tunnel (ST) and double-tunnel (DT) techniques for medial patellofemoral ligament (MPFL) reconstruction. Ninety-four patients with recurrent patellar instability were randomly divided into 2 groups, receiving either ST or DT MPFL reconstruction. Lateral reticulum release (LRR) and tibial tuberosity (TT) transfer were performed as combined procedures when necessary. Preoperative and postoperative clinical characteristics (symptoms and episodes of redislocation), functional outcomes (Kujala, Lysholm, Tegner, IKDC, and KOOS score), and radiological measurements (congruence angle, patellar tilt angle, lateral patellar angle, and lateral patellar translation) were analyzed. The analysis included data from 90 patients with 48 patients in the ST group and 42 patients in the DT group. Patients were followed up for a mean period of 37.8 (range: 27-50) months in the ST group and 38.6 (range: 25-53) months in the DT group. Forty-three patients in the ST group and 40 patients in the DT group received combined TT transfer, and all patients underwent LRR. At thelatestfollow-up, 1 patient in ST group experienced redislocation, while no patient in the DT group sustained clinical failure (P= .347). Imaging measurements decreased significantly to the normal range postoperatively. No significant difference was noted between the postoperative radiological results of the 2 groups. All clinical scores significantly improvedpostoperatively,and no significant difference was observed between the 2 groups except for the higher Lysholm score (P= .031), KOOS symptoms score (P= .021) and KOOS knee-related quality of life score (P= .043) in the DT group. Both techniques could equally mitigate the patellar lateral translation or redislocation. Our results demonstrate several significant differences in functional outcomes that favored DT MPFL reconstruction but no difference in clinical failure rates and radiological results between ST and DT MPFL reconstruction. Level I, randomized clinical trial.

Off-axis electron holography for the direct visualization of perpendicular shape anisotropy in nanoscale 3D magnetic random-access-memory devices

Perpendicular shape anisotropy (PSA) and double magnetic tunnel junctions (DMTJs) offer practical solutions to downscale spin-transfer-torque Magnetic Random-Access Memory (STT-MRAM) beyond 20 nm technology nodes, while retaining their thermal stability and reducing critical currents applied. However, as these modern devices become smaller and three-dimensionally (3D) complex, our understanding of their functional magnetic behavior is often indirect, relying on magnetoresistance measurements and micromagnetic modeling. In this paper, we review recent work that was performed on these structures using a range of advanced electron microscopy techniques, focusing on aspects specific to the 3D and nanoscale nature of such elements. We present the methodology for the systematic transfer of individual SST-MRAM nano-pillars from large-scale arrays to image their magnetic configurations directly using off-axis electron holography. We show that improved phase sensitivity through stacking of electron holograms can be used to image subtle variations in DMTJs and the thermal stability of <20 nm PSA-STT-MRAM nano-pillars during in situ heating. The experimental practicalities, benefits, and limits of using electron holography for the analysis of MRAM devices are discussed, unlocking practical pathways for direct imaging of the functional magnetic performance of these systems with high spatial resolution and sensitivity.

Structural design and mechanical responses of closely spaced super-span double tunnels in strongly weathered tuff strata

Structural design and mechanical responses of closely spaced super-span double tunnels in strongly weathered tuff strata

Design and Implementation of Negative Capacitance Based Electrostatic Doped Double Gate Tunnel Field Effect Transistor

Design and Implementation of Negative Capacitance Based Electrostatic Doped Double Gate Tunnel Field Effect Transistor

Shear failure process of rectangular tunnel: Physical experimental test and numerical back-analysis

Shear failure is a typical failure mode in underground engineering and has resulted in a large number of instability issues. To study the shear failure mechanism, physical shearing tests for rectangular tunnel of sandstone, including single rectangular tunnel (SRT) and double rectangular tunnels (DRT) specimens, were carried out under three normal stress states. During the shearing tests, the internal failure process and the external cracks evolution of tunnel specimens were recorded by video camera, and the acoustic emission (AE) events of specimens were also monitored for exposing the mesoscopic failure characteristics. In addition, the discrete element method was also applied to analyze the corresponding shear experiment of rectangular-tunnel specimens. The tested results showed that the shear strength, shear modulus of the samples were positively correlated with the normal stress. For example, the shear strength, and shear modulus of SRT increased from 5.18 MPa to 8.70 MPa, and 1.02GPa to 1.88GPa, respectively when the normal stress increased from 2.0 MPa to 5.0 MPa. More importantly, the shear failure of rectangular tunnel model can be generally divided into four stages: (i) Shearing compression stage characterized by loading contacting and compressing; (ii) Shearing micro-crack propagation stage dominated by inner particles ejection of tunnel, tensile crack initiation and shear crack propagation of specimen; (iii) Shearing fracture stage dominated by the specimen’s crack propagation, coalescence, penetration, and corresponding rock ejection; (iv) Shearing friction stage dominated by shear damage of tunnel specimen. Corresponding back analysis by numerical simulation and scanning electron microscope results indicated that the shear failure of rectangular-tunnel specimen can be classified as tensile-shear mixed failure mode. The research results provide a new cures for shear prevention and support design of rectangular tunnels in underground engineering.

Paper 17: Optimal Tibial Tunnel Placement for Medial and Lateral Meniscal Root Repair in the Setting of Multiligament Reconstructions of the Knee

Objectives:Although the risk of tibial tunnel convergence in the setting of multiligament reconstruction has been reported in the literature, the risk of tunnel convergence in the setting of posterior cruciate ligament (PCL), anterior cruciate ligament (ACL), and medial and lateral meniscal root repair has not been defined. The purpose of this study was to examine the risk of tunnel convergence and to determine optimal tunnel placement for ACL and PCL reconstruction performed in conjunction with posterior medial and lateral meniscal root repairs in the proximal tibia.Methods:Three-dimensional tibial models were created using computed tomography scans of twenty cadaveric specimens. After determining optimal tunnel entry and exit points for ACL and PCL reconstructions, and medial and lateral meniscal root repair on the models, Mimics software was used to create root tunnels. The meniscal root repair tunnels were then re-oriented to be parallel to the ACL tunnel. The initial and re-oriented configurations are illustrated in Figure 1. Tunnel convergence risk was analyzed with single and double tunnel techniques in both case scenarios.Results:There were no cases of convergence between the ACL and medial meniscal root tunnels in any of the configurations. The greatest distance between the tunnels was achieved with the single tunnel technique in parallel orientation (12.09 ± 2.78 mm). All specimens demonstrated convergence between the ACL and lateral meniscal root tunnels when the sagittal plane entry was not taken into consideration and only the anatomic root attachment was accounted for, for single and double tunnel techniques, but no convergence was seen between these tunnels with the parallel orientation in the sagittal plane. Figure 2 illustrates the reduction in the convergence risk when the meniscal root tunnels are reoriented as parallel to the ACL tunnel. There were no cases of convergence between the PCL and medial meniscal root tunnels in the original orientation, but 2/20 specimens demonstrated convergence in the parallel orientation with the double tunnel technique and no cases of convergence in the single tunnel technique. The PCL and lateral meniscal root tunnels did not demonstrate convergence in any configuration. Table 1 demonstrates the mean, minimum and maximum distances of each tunnel configuration as well as the number of cases where the distance between tunnels was <2mm. A summary of the preferred tunnel configurations for each setting, ranked by greatest tunnel distance conferred and cases of convergence, is reported in Table 2.Conclusions:There is a high risk of convergence between ACL and posterior meniscus root tunnels. Re-orienting meniscal root tunnels parallel to ACL tunnels may help reduce this risk. When PCL reconstruction is performed with ACL reconstruction and medial and lateral meniscal root repair, the single tunnel root repair technique may pose less risk over the double tunnel technique to prevent tunnel convergence between the meniscal root repair and PCL tunnels in the tibia.Figure 1. Illustration of the reconstruction of the tunnels. (A) Initial orientation where the meniscal root tunnels’ entry points on the anteromedial aspect of the tibia were created above the ACL tunnel. (B) The meniscal root tunnels re-orientated and were placed parallel to that of the ACL and aimed to exit at the anatomic attachment of the posterior roots of the meniscus. (Gold guide for the creation of the ACL tunnel and silver guide for the creation of the meniscal root tunnel)

Equivalent outcomes of ACL revision with over-the-top single and double-bundle reconstruction using hamstring tendon compared to anatomical single and double-bundle reconstruction

PurposeIn revision anterior cruciate ligament reconstruction (ACLR), our procedure of choice is the over-the-top route (OTTR) for cases where it is difficult to use a primary bone tunnel or to create a new bone tunnel due to the enlargement or malposition of the bone tunnel. Depending on the condition of the primary bone tunnel, we choose single (bone tunnel or OTTR) or double (bone tunnel or anteromedial (AM) bundle: OTTR /posterolateral (PL) bundle: bone tunnel) for femoral fixation. This study showed the results of single and double OTTR revision ACLR using the hamstring tendon.MethodsSeventy-eight patients, who underwent revision ACLR using the hamstring tendon and who could be followed up for more than 2 year, were included in this study. The methods of revision ACLR were single in 54 cases (bone tunnel: 24 cases; OTTR method: 30 cases) and double in 24 cases (bone tunnel: 16 cases; OTTR for AM bundle and bone tunnel for PL bundle: eight cases). The cause of re-injury, the meniscus and cartilage injury, the reconstruction method, and the Lysholm score, Lachman test, Pivot-shift test, and the side-to-side difference in the tibial anterior translation were evaluated before and after surgery.ResultsThere was no statistically significant difference in the Lyshom score, Lachman / Pivotshift test and side-to-side difference anterior translation of the tibia between the four groups.ConclusionsThe clinical results of single and double OTTR revision ACLR are equivalent to those of anatomic single and double bone tunnel procedures.

Direct Fabrication of Vertically Stacked Double Barrier Tunnel Junctions Based on Graphene and h-BN

Direct Fabrication of Vertically Stacked Double Barrier Tunnel Junctions Based on Graphene and h-BN

CT Derived Three Dimensional Modeling to Facilitate Minimally Invasive HVAD to HeartMate3 Left Ventricular Assist Device Exchange

<h3>Introduction</h3> The optimal surgical technique for HVAD to HeartMate 3 left ventricular assist device (LVAD) exchange will be patient dependent. We report a successful minimally invasive approach. <h3>Case Report</h3> Case: A 33-year-old woman with Adriamycin induced cardiomyopathy status post destination therapy HVAD in 2006 developed progressive alarms. Imaging revealed a large left ventricular (LV) thrombus attached to the inflow cannula. An elective HVAD to HeartMate 3 exchange was considered. Pre-operative planning: CT imaging was used to generate a three dimensional (3D) model of the heart and HVAD (A). To aid in planning both new device placement and the anastomosis between the HVAD and HeartMate 3 outflow grafts, a 3D model was generated (B). Surgical description: A left thoracotomy and 5th rib resection was used to access the HVAD and LV apex (C). The femoral vessels were cannulated for cardiopulmonary bypass and the heart was minimally manipulated. The HVAD pump, apical cuff, and exposed driveline were removed and LV clot evacuated. The HeartMate 3 apical cuff was secured to the LV apex and the pump placed in standard position (D). The HeartMate 3 (14mm) outflow graft was anastomosed to the retained HVAD (10mm) outflow graft by beveling the HVAD outflow graft (E, F). The HeartMate 3 driveline was then tunneled out of the left upper abdominal quadrant using a double tunnel technique. The thoracotomy was then closed in a standard fashion. <h3>Summary</h3> Outcome: The total bypass time was 1 hour and 20 minutes. She arrived to the intensive care unit on low dose epinephrine and vasopressin, which were rapidly weaned off. She required a total of 2 packed red blood cell transfusions. She was extubated on post-operative day 3 with normal hemodynamics and intact end organ function. She was eventually discharged in stable condition. 3D modeling was invaluable in preprocedural planning and final outcomes.

Real time investigation of double magnetic tunnel junction with a switchable assistance layer for high efficiency STT-MRAM

This work reports experimental confirmation of the working principles of a double magnetic tunnel junction (DMTJ) to achieve highly efficient spin-transfer-torque (STT) switching. This concept uses a magnetically switchable assistance layer (ASL) acting as a top perpendicular spin polarizer. The STT-induced switching dynamics were described by macrospin simulations, while the magnetic and electrical properties of the devices were investigated in switching experiments. The reversal dynamics of the storage layer/ASL coupled system were validated by time-resolved measurements of the device resistance during write operation, confirming that the storage layer is subjected to additive STT contributions both from the reference layer and the ASL throughout its parallel-to-antiparallel and antiparallel-to-parallel transitions. The STT efficiency of the ASL-DMTJ was compared to that of single MTJ stacks comprising the same storage layer and no assistance layer. The figure of merit ∆/Ic (stability/critical current) was found to nearly double in devices of 80 and 100 nm diameter, with a smaller 30% increase obtained for 50 nm diameter cells.

Field measurement analysis of the influence of simultaneous construction of river channel and bridge on existing double shield tunnels

This study presents the construction of a river channel and a bridge adjacent to existing metro tunnels in Changzhou. The influence of simultaneous construction on these existing tunnels was investigated via 3D numerical modelling to predict tunnel deformation before construction. Then, a targeted protection scheme was developed according to the obtained numerical results. The full construction period field monitoring scheme can monitor tunnel responses during construction. Subsequently, the safety of the tunnel structures was evaluated according to the monitoring results, and the evolution of tunnel deformations was analysed. The analytical results can help to clarify the influence characteristics of different construction stages, verify the effect of the proposed protection scheme, and determine the disturbance mechanism of short-distance pile construction. According to the results, the tunnel deformation mainly occurred during pile construction and river channel excavation, and the tunnel vertical displacement and convergence were mainly affected by the construction. The anti-floating scheme of the partition excavation and casting effectively controlled the tunnel heave with an alarm value of approximately 6 mm. The penetration of the short-distance casing resulted in a tunnel deformation. The main construction influence area of the casing pile was within 6D (D is the pile diameter).

Study on Antiseismic Effect of Different Thicknesses of Shock Absorption Layer on Urban Shallow Buried Double Arch Rectangular Tunnel

With the development of urban tunnels, more and more studies focus on the antiseismic design of tunnels. Setting up a shock absorption layer is a very effective means in the earthquake resistance of an urban tunnel. In this paper, in order to study the influence of the thickness of a shock absorption layer on the antiseismic effect of the urban shallow buried double arch rectangular tunnel, the Tengzhou–Fenghuang tunnel is used as the research background. Firstly, the model is established by finite element software to analyze the tunnel with 50 mm, 100 mm, and 150 mm thick shock absorption layers, and analyze the tunnel displacement, stress, and safety factors of different models under the action of a seismic wave. Finally, the calculation results are compared and analyzed with those of the model without the shock absorption layer to summarize the thickness of the shock absorption layer suitable for urban shallow buried rectangular tunnels. The results show that the displacement and stress of tunnel lining are significantly reduced, and the safety factor is significantly improved after setting the shock absorption layer. Among them, the tunnel with a 100 mm thick shock absorption layer has the greatest reduction in principal stresses, the greatest increase in safety factor, and the best antiseismic effect, while the construction costs are not high. It is recommended that the urban shallow buried double arch rectangular tunnel be constructed with a 100 mm thick shock absorption layer.

Study on temporal and spatial evolution law for dust pollution in double roadway ventilation system of short wall continuous mining face.

To explore the laws of variations in the evolution of dust pollution within a double tunnel ventilation system at a short wall continuous mining face, a numerical simulation of air flow movement was conducted in this study. Results showed that after the wind flowing in the supporting and heading tunnels reached the head, the wind sides returned at speeds of 6.5 and 10.3m/s, respectively. Affected by the air volume and pressure differences between the two tunnels, part of the air flow entered the connecting tunnel at an average speed of 0.8m/s and moved to the heading tunnel. Affected by the turbulence at the driving face, a high dust concentration zone with a maximum dust concentration of 1700mg/m3 was formed in the tunnels at a distance of 15m from the heading. Dust blocked by the shuttle car accumulated and settled near it and formed a dust zone with an approximate average concentration of 750mg/m3 at a distance of 19-23m from the heading. The dust produced by the bolt machine formed a dust mass with an average concentration of 900mg/m3 at a distance of 0.5-4.5m from the head. Quantitative analyses of the changes in dust concentration with time at the position of a driver of the continuous mining machine, shuttle car, and anchor bolt machine were conducted, and functional formulae for the quadratic distribution were obtained. Suggestions for dust control were then proposed.

Tunable tunneling magnetoresistance in in-plane double barrier magnetic tunnel junctions based on B vacancy h-NB nanoribbons.

Magnetic tunnel junctions (MTJs) have attained new opportunities due to the emergence of two-dimensional (2D) magnetic materials after they were proposed more than forty years ago. Here, an in-plane double barrier magnetic tunnel junction (IDB-MTJ) based on B vacancy h-NB nanoribbons has been proposed firstly, and the transport properties have been studied using density functional theory combined with the nonequilibrium Green's function method. Due to its unique structural characteristics, the tunneling magnetoresistance (TMR) ratio can be tuned and the maximum TMR can reach 1.86 × 105. The potential applications of the IDB-MTJ in magnetic random-access memories and logical computation have also been discussed. We find that the IDB-MTJs have great potential in magnetic random-access memories and logical computation applications.

Spin Torque Oscillator and Magnetization Switching in Double Barrier Rashba Zeeman Magnetic Tunnel Junction

Spin Torque Oscillator and Magnetization Switching in Double Barrier Rashba Zeeman Magnetic Tunnel Junction

Performance investigation of hetero gate dielectric DGTFET with drain pocket for analog/RF applications

This work examined a double gate Tunnel FET (DGTFET) employing a heterogeneous gate dielectric (HD) scheme and a drain pocket (DP) for analog/ RF applications. Two different gate dielectric HfO2 (εox = 21) and Al2O3 (εox = 10) are compared with DP-DGTFET (without HD) for ION, IAMB, Vth, SS, and ION/IOFF. It is observed that as the value of the dielectric constant increases, ION rises with the reduction in the width of the tunneling barrier at the source-channel interface. However, ION/IOFF ratio for Al2O3 based device is two orders of magnitude better than the device employing HfO2. Further RF performance figures of merits (FOMs) CG, UPG,fT, Fmax, Gma, and admittance parameters are also inspected for all devices under concern using TCAD simulations.