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ABSTRACT Two‐dimensional analysis of tunnel design based on the convergence–confinement method, although commonly used in tunnel design, may not always be applied. For example, in squeezing grounds, if the support is installed very close to the tunnel face, three‐dimensional numerical modeling is required but is computationally expensive. Therefore, it is usually performed before or after tunnel excavation. A machine learning approach is presented here as an alternative to costly computations. Two surrogate models are developed based on synthetic data. The first model aims to assess the support pressure and the radial displacement at equilibrium in the lining and the radial displacement occurring close to the face at the installation distance of the support. The second model is intended to compute the extrusion of the core considering an unlined gallery. It is assumed a circular tunnel excavated in a Mohr–Coulomb elastoplastic perfectly plastic ground under an initial isotropic stress state. In particular, the bagging method is applied to neural networks to enhance the generalization capability of the models. A good performance is obtained using relatively scarce datasets. The modeling of the surrogate models is explained from the creation of the synthetic datasets to the evaluation of their performance. Their limitations are discussed. In practice, these two machine learning tools should be helpful in the field during the excavation phase. [ABSTRACT FROM AUTHOR]

As a prototypical example for a heterostructure combining a weakly and a strongly interacting quantum many-body system, we study the interface between a semiconductor and a Mott insulator. Via the hierarchy of correlations, we derive and match the propagating or evanescent (quasi) particle solutions on both sides and assume that the interactions among the electrons in the semiconducting regions can be absorbed by an effective potential. While the propagation is described by a band-like dispersion in both the weakly and the strongly interacting case, the inverse decay length across the interface follows a different dependence on the band gap in the Mott insulator and the semiconductor. As one consequence, tunnelling through a Mott insulating layer behaves quite differently from a semiconducting (or band insulating) layer. For example, we find a strong suppression of tunnelling for energies in the middle between the upper and lower Hubbard band of the Mott insulator. [ABSTRACT FROM AUTHOR]

Highly efficient charge injection and charge trapping stability of the tunneling layer are of desirable and practical importance to transistor memory applications. However, both of which can be contradictory to the nature properties of its material. It is herein demonstrated that lowering the energy mismatch of the tunneling layer by employing a longer conjugation length of the polymer can improve the charge injection efficiency, albeit the trapped charges will be easily diminished and finally losing its memory characteristics, and vice versa. To further elaborate and verify this concept, both materials are blended with distinct nature of properties as the tunneling layer in pentacene‐based transistor devices. As the results, the device using 300 nm SiO2 with optimum blending ratio displays a broad memory window of ≈77.6 V which is superior to the non‐blended tunneling layer carrying appropriate energy levels and band gap energy, not to mention, revealing fast operation time (≈1 s), low driving voltage (≈20 V), long retention (>104 s), and high switching stability over 50 cycles with on–off ratio of >104. Most importantly, this finding shed insight into the design of tunneling materials for advancing organic transistor memory technologies based on tunneling‐effect‐boosted interfacial charge trapping. [ABSTRACT FROM AUTHOR]

Significantly high voltage deficit and high diode ideality factor in Sb2Se3 solar cells due to space-charge region recombination, conduction band offset, and interface defects at the Sb2Se3/CdS heterojunction prompting elevated interfacial recombination. We proposed and theoretically analyzed an ultrathin tunnel layer to address the interfacial issues. An investigation is conducted into the function of the tunnel layer (ultrathin, wide band gap insulating layer) in mitigating the interface trap states and reducing interface recombination. The tunnel layer at the Sb2Se3/CdS junction has demonstrated a lower recombination current. The performance of devices demonstrated a sustained level of stability with an increase in defects when equipped with a tunnel layer, contrasting the continuous performance degradation observed in devices without a tunnel layer. The device incorporating a tunnel layer achieved an efficiency (η) of 13.9%, VOC of 0.74 V, JSC of 32.7 mA/cm2, and FF values, of 57.2%, respectively. Conversely, the device lacking a tunnel layer at the interface exhibited efficiency parameters of 9.2%, with VOC at 0.4 V, JSC at 32.7 mA/cm2, and a fill factor of 70.5%. The results pertaining to the optimized device with interface passivation through a tunnel layer are anticipated to serve as a catalyst for experimentation within the field. [ABSTRACT FROM AUTHOR]

In this study, two new structures are proposed for reverse-conducting insulated gate bipolar transistors (RC-IGBT) that effectively prevent snapback by relocating the N-collectors and utilizing silicon–germanium in the collector region of each device. The forward mode of the proposed structures shows IC− VC characteristics without snapback, since the position of the N-collector is changed to prevent electron extraction. In the reverse mode, the silicon–germanium induces currents through tunneling and impacts the ionization mechanisms. Importantly, the proposed structures generate a stable current value even if there are errors in the length of the N-collector during ion implantation, which enhances the reliability of the device. In addition, the proposed structures exhibit similar values for the breakdown voltage at around 700 V and the turn-on and turn-off losses when compared to the conventional RC-IGBT. Thus, this paper improves the reliability of RC-IGBTs by mitigating the snapback effect while maintaining their unique electrical properties. [ABSTRACT FROM AUTHOR]

With the rapid development of urban rail transit systems, the shield tunneling technology has become indispensable for urban tunnel construction. However, the theoretical study of the shield tunneling process is not mature enough in view of the complex mechanical properties of the shield machine and the surrounding soil. In this paper, the attitudinal change behavior of earth pressure balanced shield machines (EPB) during the tunneling process is investigated, and comprehensive theoretical expressions for the normal and frictional forces acting on the shield periphery and cutter face are derived. The discretization equations for the normal forces acting on the shield periphery are given based on the meshing and interpolation method. Based on the above studies, the mechanical equilibrium equations of the shield are established to accurately solve for the shield forces and shield attitude characteristics, as well as to verify the computational accuracy of the theoretical solution. Through the analysis of a practical project involving longitudinal tunneling, it is confirmed that the theoretical calculation model can better reflect the mechanical behavior of the earth pressure balanced shield. [ABSTRACT FROM AUTHOR]

The Great Chinese Famine is considered one of the most traumatic events recorded in human history and has a long‐lasting influence on the survivors' behaviors. Previous studies have linked the CEOs' early‐life experiences to corporate decisions and managerial behaviors, but does experience affect corporate governance? We investigate the impact of the CEO's early‐life famine experience on tunneling using a data set consisting of 11,573 firm‐year observations from the Chinese manufacturing companies publishing A‐shares on the main board from 2006 to 2016. We find that companies run by CEOs who experienced the Great Chinese Famine (1959–1961) in their early life are less likely to collude with controlling shareholders to expropriate minority shareholders than those who did not suffer the hardships of famine. We further make mediation tests to confirm two channels: risk aversion and empathy for poverty. The overall findings align with the view of imprinting theory: CEOs' experiences of adverse events in their early life have a lasting impact on their later‐life behaviors. [ABSTRACT FROM AUTHOR]

In order to investigate the stress and strain state of the surrounding rock and the effect of supporting structure of the deep buried tunnel through the fault zone in mountainous area, taking Lianfeng Mountain Tunnel Project as the research background, based on ABAQUS large-scale finite element numerical computation program, the mechanics calculation model of the construction of the deep buried tunnel through the fault zone was established, and the change rule of the structural stress state and the horizontal and vertical settlement rule of the mountain after the tunnel excavation and lining were studied. The results showed that the settlement in the fault zone during tunnel excavation was much larger than that in the normal rock body; the stress difference between the surrounding rock and the peripheral mountain body at the fault zone was larger, and the stress difference at the junction with the normal mountain body was larger; the settlement caused by tunnel excavation affected the range of 50 m, and the settlement at the center of the twin tunnels increased with the increase of vertical height; the excavation of the second tunnel in the construction of the twin tunnels caused the increase of the strain of the first tunnel. [ABSTRACT FROM AUTHOR]

Herein, analytical modeling of Fe3O4/x(≈1.1 nm)/Co (x = rubrene, C60, and bathocuproine (BCP)) magnetic tunnel junctions (MTJs) has been performed using rubrene, C60, and BCP as organic spacer layers. The simulation is considered as nonequilibrium Green's function assuming spin precession at ferromagnet/organic semiconductor (FM/OSC) interface defect states. The voltage‐dependent resistances for both parallel (RP) and antiparallel (RAP) orientations have been observed to be dependent on spin injection from FM/OSC defect states. Pinning well‐dependent defect state depths have been associated with band misalignment‐induced lattice distortion at FM/OSC interface of the devices. The large tunnel magnetoresistance (TMR) response for rubrene‐based MTJ device has been attributed to a higher change of FM/OSC defect state depths with voltage. High TMR may have reduced spin torque‐dependent spin precession, leading to lower spin transfer torque for the rubrene device. Hence, engineering of defect states at the FM/OSC interface may lead to the successful realization of enhanced TMR in organic spacer MTJs for high‐performance spintronic memory applications. [ABSTRACT FROM AUTHOR]

In today's urban development, Earth Pressure Balance (EPB) Tunnel Boring Machines (TBMs) play a vital role. It's crucial to design a comprehensive monitoring system to control surface settlement and prevent damage to surface structures. This study focuses on creating prediction models for estimating ground surface settlement. Two soft computing techniques, namely ANN-CFB and ANN-BP, were used for this purpose. The models were validated using operational data from the Qom metro Line A, specifically the section between A14 and A10 stations. Additional input parameters were incorporated using an image processing approach to include soil properties for each segment. As a result, the most accurate ANN technique was employed to predict ground surface settlements for the mentioned project. The correlation coefficients for training, testing, validation, and the overall result were found to be 0.99439, 0.97873, 0.96381, and 0.98824, respectively. Through sensitivity analysis, the study explored the connections between different parameters and ground surface settlement. The outcomes reveal strong agreement between predicted values and real data. Notably, the parameter 'cutter head torque' exhibited the highest impact on surface settlement (8.48%), while 'Pressiometric Modulus (Ep)' had the least impact (4.24%). [ABSTRACT FROM AUTHOR]

Tunnels traditionally regarded as resilient to seismic events have recently garnered significant attention from engineers owing to a rise in incidents of seismic damage. In this paper, the reflection characteristics of the elastic plane wave incident on the free surface are analyzed, and the matrix analysis method SWIM (Seismic Wave Input Method) for the calculation of equivalent nodal loads with artificial truncated boundary conditions for seismic wave oblique incidence is established by using coordinate transformation technology, according to the displacement velocity and stress characteristics of a plane wave. The results show that the oblique incidence method is more effective in reflecting the traveling wave effect, and the "rotational effect" induced by oblique incidence must be considered for P wave and SV wave incidence, including the associated stress and deformation. This effect exhibits markedly distinct rotational phenomenon. In particular, the P wave incidence should be focused on the vault and the inverted arch due to the expansion wave. With the increase of the oblique incidence angle, the structural stress and deformation are rotated to a certain extent, and the values are significantly increased. Simultaneously, the shear action of the SV wave may result in "ovaling" of the tunnel structure, thereby facilitating damage to the arch shoulder and the sidewall components. As the oblique incidence angle, the potentially damaging effects of the "rotational effect" to the vault and the inverted arch, but the numerical value does not change significantly. In addition, in comparison to a circular cross-section, the low-frequency amplification of seismic waves in the surrounding rock and the difference of frequency response function in different parts of the lining are more pronounced. In particular, the dominant frequency characteristics are significant at P wave incidence and the seismic wave signal attenuation tends to be obvious with increasing incidence angle. In contrast, SV waves exhibit more uniform characteristics. [ABSTRACT FROM AUTHOR]

This research replaced the traditional hole source layers in a conventional LED with a tunnel junction. In conventional light-emitting diodes (LEDs) two hole injecting layers (p-GaN and p-AlxGa1-xN) have been used, in which holes have to surpass greater energy barriers that hindered holes injection. A heavily doped GaN tunnel junction (TJ) has been used as a replacement for conventionally used hole injection layers, which has reduced the energy barriers for holes and increased the electron confining ability of wells. As a result, the internal quantum efficiency (IQE) of the LED has increased from 52% to 72%. Instead of GaN TJ, Al0.10Ga0.90N – GaN hybrid tunnel junction (HTJ) has been introduced to lower the efficiency droop and raise the efficiency further to 81% simultaneously. Using TJ and HTJ, we have demonstrated that the conventional hole’s source layer can be replaced by TJs, which results in better hole injection because of reduced barrier height, increased electron confinement, greater electron–hole radiative recombination, and higher spontaneous emission intensity.

Abstract The low-bias current–voltage technique was utilized to study charge transport in single-stranded DNA (ssDNA), assessing the method’s effectiveness for future studies aimed at estimating the degree of mutation or DNA damage. In the paper, we showed that charge carrier transfer processes in ssDNA can be precisely monitored using low-bias currents. We used negative differential resistance and the Fowler-Nordheim model to differentiate the charge transport mechanisms observed in a device composed of gold electrode-thiol-ssDNA junctions. It was possible to distinguish the processes at the two junctions (Au/thiol and thiol/DNA) due to their distinct current–voltage characteristics. We observed positive charge carrier tunneling, which we attribute to oxidation and reduction processes in the nucleobases of the ssDNA. Our results suggest that even minor changes in DNA chains can be accurately detected using the described methodology.

To study the calculation method of rock pressure in jointed rock tunnels, based on the theory of tunnel pressure arch, the influence of rock hardness, integrity, and shear strength of structural planes on tunnel pressure arch was analyzed through discrete element numerical simulation. Multiple linear regression was applied to fit the multi factor rock pressure formula, and the applicability of the fitting formula was analyzed in combination with engineering support. The results indicate that the range of pressure arch in jointed rock tunnels is the deflection point from the arch crown to the direction of maximum principal stress; The height of tunnel pressure arch decreases with the increase of joint spacing and shear strength of structural planes, and the influence of rock mechanics parameters on the height of pressure arch is relatively small; Compared with the measured rock pressure on site, the calculation error is within 15%. The proposed formula for surrounding rock pressure has good applicability and provides a new approach for calculating the surrounding rock pressure of jointed rock.

Abstract Given the influence of air intake from inclined shafts in existing tunnel ventilation systems on train comfort and aerodynamic safety, a numerical analysis method is used to study the comfort and aerodynamic safety of operating trains under three conditions—inclined shaft closed and inclined shaft open without and with air intake—and to explore the variation law of transient pressure and aerodynamic force (lift coefficient, transverse force coefficient, and overturning moment coefficient). Combined with practical engineering and requirements, the influence of inclined shaft air intake on train operation comfort and aerodynamic safety is analyzed. Through this research, the influence of using air intake from the inclined shaft of an existing tunnel, a ventilation scheme of the new Wushaoling Tunnel, on the comfort and aerodynamic force of trains is revealed, and the comfort and aerodynamic safety of trains in an actual project are evaluated, verifying the rationality of the ventilation scheme of the Wushaoling Tunnel.

This paper conducts a theoretical analysis of ground settlements due to shield tunneling in multi-layered soils which are usually encountered in urban areas. The proposed theoretical solution which is based on the general form of the Mindlin's solution and Loganathan-Poulos formula can comprehensively consider the in-process tunneling parameters including: unbalanced face pressure, shield-soil friction, unbalanced tail grouting pressure, unbalanced secondary grouting pressure, overloading during tunneling and the ground volume loss. The method is verified by comparing with the field data from the Qinghuayuan Tunnel Project in terms of the ground surface settlements along the longitudinal and transverse direction. Due to the local settlement or heave caused by the certain tunneling parameters, the ground surface settlements calculated using current solution along the longitudinal direction presents an irregular S-shaped curve instead of the traditional S-shaped curve. Results also find that the effect of the unbalanced secondary grouting pressure and the overloading during tunneling cannot be ignored.

The fundamental question of "what is the transport path of electrons through proteins?" initially introduced while studying long-range electron transfer between localized redox centers in proteins in vivo is also highly relevant to the transport properties of solid-state, dry metal-protein-metal junctions. Here, we report conductance measurements of such junctions, Au-(Azurin monolayer ensemble)-Bismuth (Bi) ones, with well-defined nanopore geometry and ~103 proteins/pore. Our results can be understood as follows. (1) Transport is via two interacting conducting channels, characterized by different spatial and time scales. The slow and spatially localized channel is associated with the Cu center of Azurin and the fast delocalized one with the protein's polypeptide matrix. Transport via the slow channel is by a sequential (noncoherent) process and in the second one by direct, off-resonant tunneling. (2) The two channels are capacitively coupled. Thus, with a change in charge occupation of the weakly coupled (metal center) channel, the broad energy level manifold, responsible for off-resonance tunneling, shifts, relative to the electrodes' Fermi levels. In this process, the off-resonance (fast) channel dominates transport, and the slow (redox) channel, while contributing only negligibly directly, significantly affects transport by intramolecular gating. [ABSTRACT FROM AUTHOR]

Segmental tunnel linings have a complex structural behavior that is difficult to predict. Full-scale in situ structural monitoring allows us to gain access to these structures, observe the acting mechanisms, and better understand the actual structural behavior under realistic boundary conditions. In a recent structural monitoring project in Frankfurt, Germany, strains, deformations, and temperatures were measured at the segmental lining of a twin-tube tunnel boring machine (TBM) tunnel. Hereby, internal forces were back-calculated from the strain measurements. The results of the monitoring are presented and discussed in this paper. The measurements began immediately after the assembly of the segments and have been performed continuously over several years. Because of that, it was possible to observe that the internal forces differ significantly between the construction stage and the final state. During the construction stage, the internal forces develop quickly within hours after ring assembly, showing a distribution along the lining's circumference that is hard to predict. Almost all radial deformations occur during this period and remain unchanged afterward. After this first early phase, a period of stress redistribution follows, including significant changes in the internal forces. At its end, the stable, final state is reached. In this state, the internal forces match better with expectations. In the monitored areas, the stresses during the construction stage slightly exceeded those of the final state, which should be avoided for economic reasons. Additional investigations regard the temperature development within the lining, the influence of the second tube construction on the already built tube, and the development of longitudinal ring interaction over time. The latter significantly influences the structural behavior, but its development is often subject to uncertainties. In this case, it was observed that the longitudinal interaction decreases considerably over time. Practical Applications: In the structural design of segmental tunnel linings, structural or geotechnical engineers have various options regarding the available calculation methods and modeling strategies. All of these options are part of the state of the art, and the selection is up to the engineer. However, the results can be quite different depending on the chosen option. Consequently, uncertainties remain regarding the real linings' internal forces and structural reliability. The actual mechanisms can be identified by investigating the real structural behavior of segmental tunnel linings with in situ structural monitoring. Then, with back-analyses, on the one hand, it can be tested to determine how well different calculation methods and modeling strategies correspond to reality. On the other hand, the monitoring data can contribute to improving existing calculation methods, developing new modeling approaches, and establishing more detailed recommendations or optimizations regarding the design and construction of segmental tunnel linings. This paper presents findings derived from a structural monitoring project on a segmental lining. Different mechanisms and aspects, sometimes uncertain or debatable in tunnel design, are discussed regarding their real in situ appearance. The gained data will also be used for further back-analyses and investigations. [ABSTRACT FROM AUTHOR]

Boltzmann carrier statistics restrict the sub‐threshold swing (SS ≥ 60 mVdec–1) and, consequently, the supply voltage (≈ 1 V) of the thermionic transistor. This primary bottleneck results in rapidly increasing power consumption, heating, and associated reliability/scalability challenges as more devices are packed into a small footprint. Despite significant efforts from the device community, a suitable sub‐thermionic alternative is yet to emerge. In this work, an attempt is made to understand the physics of Schottky barrier FETs demonstrating SS < 60 mVdec–1, as evident in some experimental results. Employing the in‐house TCAD tool, the electrostatic potential in the device is accurately modeled with the sweeping gate bias. Next, the Tsu–Esaki model is used to compute the tunneling current. The analysis shows that the steep SS results from an abrupt change in the tunneling barrier profile, from a step‐like to a triangular‐like. However, in the ON regime, the drift component begins to dominate the transfer characteristics. Thus, the subtle interplay between the drift and tunneling components of transport leads to SS < 60 mVdec–1 in OFF‐state with improved Ion${\rm I}_{on}$ in ON‐state. Finally, using the calibrated model, the performance metrics of an all‐2D material‐based CMOS inverter operating at a low VDD ≈ 0.6 V are projected. [ABSTRACT FROM AUTHOR]

We introduce the quantum currents for quantum systems with an SU(1,1) dynamic symmetry group whose evolution is governed by a non-linear Hamiltonian possessing a continuous spectrum and apply them to the analysis of the tunneling dynamics on the hyperbolic phase space. [ABSTRACT FROM AUTHOR]

The logistics transportation system is critical to the United States economy. Underground Logistics Transportation (ULT) is a class of automated transportation systems in which vehicles carry freight through pipelines and tunnels between terminals. Being able to use a part of the underground space of existing highways will greatly facilitate the construction of such pipelines and tunnels and reduce their construction costs. Underground Logistics Transportation (ULT) could be the answer to make freight transport more sustainable and competitive. Texas highways and railroads are expected to increase by nearly 207% from 2003 to 2030. Truck tonnage will grow by 251%, while rail tonnage is forecasted to increase 118%. The number of trucks carrying NAFTA goods will increase by 263%, and the number of rail units will grow by 195%. This will have a profound impact on the highway and rail systems. The objective of this paper is to present requirements and operational components for three types of ULT lines: standard shipping containers, a standard crate size, and a standard pallet size. This study examines the use of ULT as a mode of underground transportation with the help of three case studies. This research shows that ULT is financially viable, feasible, greener, cost effective, and can become an important part of intermodal freight mobility. [ABSTRACT FROM AUTHOR]

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This research examines the relationship between excavations and tunnel responses, emphasizing the influence of geometric factors on tunnel heave. Utilizing an exponential correlation between heave and unloading ratio, the study investigates into stress changes with increasing excavation depth. Maintaining a constant axial horizontal distance proves crucial for stable tunnel responses. FLAC3D numerical modeling highlights increased stress-strength ratios near excavations, impacting the tunnel crown. Water ingress induces soil consolidation, leading to additional deformations, while adverse excavation conditions can cause leaks, dislocations, and cracks in the tunnel lining. The study also analyzes rock behavior under diverse loading and excavation conditions, revealing stress point relationships with the yield surface in principal stress space. [ABSTRACT FROM AUTHOR]

In sandy cobble stratum, the contents of rock blocks along the tunnel line present to be different. The tunneling-induced ground deformation under different rock contents is perceived as a main concern. Considering the heterogeneity of ground material, the meso-scale numerical models of sandy cobble strata were used to simulate tunnel excavation, in which the rock blocks and soil matrix were treated as separated constituents. By comparing the ground stress of simulation results with that of theoretical values, the applicability of meso-scale models was verified. The simulation results show that the rock content has a significant effect on the ground deformation performance. With the increase of rock content from 0 to 50%, the maximum ground settlement and the expansion of plastic zone gradually decreases, and the variation rule of the maximum ground settlement with rock content can be described by a normal distribution function. Meanwhile, the tunnel deformation pattern changes from non-uniform convergence to uniform convergence. It is also found that the relationship between the maximum subsurface settlement or the width coefficient of subsurface settlement trough and subsurface depth can be described by a power function, respectively. [ABSTRACT FROM AUTHOR]

Photolithography has been the foundational fabrication paradigm in current high‐performance electronics. However, due to the limitation in fabrication resolution, scaling beyond a 20‐nm critical dimension for metal conductors presents a significant challenge for photolithography. Structural DNA nanotechnology emerges as a promising alternative to photolithography, allowing for the site‐specific assembly of nano‐materials at single‐molecule resolution. Substantial progresses have been achieved in the ultra‐scaled DNA‐based conductors, exhibiting novel transport characteristics and small critical dimensions. This review highlights the structure‐transport property relationship for various DNA‐based conductors and their potential applications in quantum /semiconductor electronics, going beyond the conventional scope focusing mainly on the shape diversity of DNA‐templated metals. Different material synthesis methods and their morphological impacts on the conductivities are discussed in detail, with particular emphasis on the conducting mechanisms, such as insulating, metallic conducting, quantum tunneling, and superconducting. Furthermore, the ionic gating effect of self‐assembled DNA structures in electrolyte solutions is examined. This review also suggests potential solutions to address current challenges in DNA‐based conductors, encouraging multi‐disciplinary collaborations for the future development of this exciting area. [ABSTRACT FROM AUTHOR]

The molecular transport and quantum tunneling of H2 and H2O molecules through nanoporous graphene is studied using computational modeling and first-principles density functional theory. It is demonstrated that molecules with sufficiently high kinetic energies can tunnel through nanopores. It is also demonstrated that molecules can be trapped in front of a nanopore or behind it. These investigations help us learn the behavior of molecules in and around the nanopores of graphene. They also help us learn the fundamentals of molecular tunneling. We believe nanoporous graphene can play important roles for gas separation and nanofiltration. [ABSTRACT FROM AUTHOR]

This paper presents the design and analysis of an enhanced tunnel field-effect transistor (TFET) structure. The proposed structure comprises a dual source and a double gate, aiming to enhance the DC characteristics of the TFET. The dual source concept is used in the structure with two homogeneous gates, which play a major role in boosting the tunneling parameters. It also examines the affectability of source dimensions and drain doping on the performance of the proposed device. Furthermore, we have compared our proposed structure with the single source device. The proposed device after optimization exhibits an extraordinary ION/IOFF ratio of 2.33 × 1013, with an IOFF of 6.25 × 10−19A/µm, and decent Ion of 1.46 × 10−5A/µm along with a subthreshold swing (SS) of 43 mV/dec. The device characteristics have been analyzed in the presence of interface traps. The electrical parameters have been quantified against various types and concentrations of traps. The performance of the proposed device has been compared with the existing TFET structures. [ABSTRACT FROM AUTHOR]

Tunneling processes in de Sitter spacetime are studied by using the stochastic approach. We evaluate the Martin–Siggia–Rose–Janssen–de Dominicis (MSRJD) functional integral by using the saddle-point approximation to obtain the tunneling rate. The applicability conditions of this method are clarified using the Schwinger–Keldysh formalism. In the case of a shallow potential barrier, we reproduce the Hawking–Moss (HM) tunneling rate. Remarkably, in contrast to the HM picture, the configuration derived from the MSRJD functional integral satisfies physically natural boundary conditions. We also discuss the case of a steep potential barrier and find an interesting Coleman–de Luccia (CDL) bubblelike configuration. Since the starting point of our analysis is the Schwinger–Keldysh path integral, which can be formulated in a more generic setup and incorporates quantum effects, our formalism sheds light on further studies of tunneling phenomena from a real-time perspective. [ABSTRACT FROM AUTHOR]

We present the experimental finding of multiple simultaneous two-fold degeneracies in the spectrum of a Kerr oscillator subjected to a squeezing drive. This squeezing drive resulting from a three-wave mixing process, in combination with the Kerr interaction, creates an effective static two-well potential in the phase space rotating at half the frequency of the sinusoidal drive generating the squeezing. Remarkably, these degeneracies can be turned on-and-off on demand, as well as their number by simply adjusting the frequency of the squeezing drive. We find that when the detuning Δ between the frequency of the oscillator and the second subharmonic of the drive equals an even multiple of the Kerr coefficient K, Δ/K = 2m, the oscillator displays m+1 exact, parity-protected, spectral degeneracies, insensitive to the drive amplitude. These degeneracies can be explained by the unusual destructive interference of tunnel paths in the classically forbidden region of the double well static effective potential that models our experiment. Exploiting this interference, we measure a peaked enhancement of the incoherent well-switching lifetime, thus creating a protected cat qubit in the ground state manifold of our oscillator. Our results illustrate the relationship between degeneracies and noise protection in a driven quantum system. [ABSTRACT FROM AUTHOR]

Given the influence of air intake from inclined shafts in existing tunnel ventilation systems on train comfort and aerodynamic safety, a numerical analysis method is used to study the comfort and aerodynamic safety of operating trains under three conditions—inclined shaft closed and inclined shaft open without and with air intake—and to explore the variation law of transient pressure and aerodynamic force (lift coefficient, transverse force coefficient, and overturning moment coefficient). Combined with practical engineering and requirements, the influence of inclined shaft air intake on train operation comfort and aerodynamic safety is analyzed. Through this research, the influence of using air intake from the inclined shaft of an existing tunnel, a ventilation scheme of the new Wushaoling Tunnel, on the comfort and aerodynamic force of trains is revealed, and the comfort and aerodynamic safety of trains in an actual project are evaluated, verifying the rationality of the ventilation scheme of the Wushaoling Tunnel. [ABSTRACT FROM AUTHOR]

Reliable and timely prediction of the shield tunneling path is essential to avoid deviation and successfully complete a tunneling project. This study presents a reinforcement learning-based new optimal model for improving the forecasting accuracy of the shield tunneling path and alleviating shield drivers' over-reliance on their practical experience. This model integrates the Q-learning network with a metaheuristic gray wolf algorithm to explore and exploit the implicit information of the shield machine through Q-Table. The proposed method is applied to a field tunneling case with data collected from a real tunneling scenario in Tianjin City, China. The model is also evaluated using various numerical benchmark approaches and compared to a deep learning method. The results show that the proposed model produces an accurate prediction with a root-mean-square error of 0.539 and correlation coefficient of 0.925 for pitch values. A sensitivity analysis indicated that the thrust force and the buried depth have a significant influence on the prediction of shield tunneling trajectory. [ABSTRACT FROM AUTHOR]

In this review, the concepts of quantum tunneling and parity violation are introduced in the context of chiral molecules. A particle moving in a double well potential provides a good model to study the behavior of chiral molecules, where the left well and right well represent the L and R enantiomers, respectively. If the model considers the quantum behavior of matter, the concept of quantum tunneling emerges, giving place to stereomutation dynamics between left- and right-handed chiral molecules. Parity-violating interactions, like the electroweak one, can be also considered, making possible the existence of an energy difference between the L and R enantiomers, the so-called parity-violating energy difference (PVED). Here we provide a brief account of some theoretical methods usually employed to calculate this PVED, also commenting on relevant experiments devoted to experimentally detect the aforementioned PVED in chiral molecules. Finally, we comment on some ways of solving the so-called Hund's paradox, with emphasis on mean-field theory and decoherence. [ABSTRACT FROM AUTHOR]

This study investigates the impact of controlling shareholder share pledging (henceforth, share pledging) on tunneling in an emerging market. Using a large sample of Chinese-listed firms from 2004 to 2019, we find that the presence of share pledging results in a 9.7% increase in tunneling, and higher controlling shareholders' pledging ratio is associated with more severe tunneling. The positive relationship between share pledging and tunneling is significantly stronger in non-SOEs than in SOEs. We also find that strong monitoring of multiple large shareholders, high analysts' coverage, and strong institutional environment help mitigate the tunneling induced by share pledging. We further find that the cumulative abnormal returns around the interim announcements of share pledging are significantly negative. Overall, the findings in this study suggest an exacerbating effect of share pledging on tunneling in an emerging market when external monitoring and investor protection is relative weak. [ABSTRACT FROM AUTHOR]

Transmission gate has been implemented using tunnel field-effect-transistor (TFET) in the presented work. This work demonstrates the benefits of replacing MOS devices with TFET from conventional CMOS circuits for low-power sub-micron technology. TFET with few structural modifications is described as a worthy contender for the MOSFETs. As an illustration to it the transmission gate block, which is one of the popular logic styles, is implemented using modified junction less TFETs with P + pocket near the source end. In this work, firstly, a single gate TFET with buried SOI followed by double gate (DG) TFETs is demonstrated for implementation of the transmission gate (TG). Both the devices have junction less structure with a p + pocket or n + pocket region in n-JL TFET or p-JL TFET respectively towards source. The major parameter of evaluation is voltage transfer characteristics, output characteristics and device ON and OFF current for obtaining standard ON/OFF current ratio in low-power logic circuit implementations. The fabrication steps of both devices are also depicted with the help of projected lithographic processes. The device implementation and simulation are carried out on the Cogenda Visual TCAD tool at a 20 nm technology node. [ABSTRACT FROM AUTHOR]

Tunnelling activities in urban areas are always associated with surface and subsurface ground subsidence, which may affect the stability of nearby structures and utilities. During and after tunnel construction, the surrounding building is subjected to different.deformations and strains due to immediate settlement. The constructed buildings should be able to bear the effect of change in the total, differential settlement and bending moment of raft according to the tunneling activity. The soil settlement around the tunnel and the ground movement above the tunnel should be taken in consideration too. This study focuses on the settlement of raft foundation according to tunneling activity using single and double tunnels. 2D numerical model was conducted to simulate the excessive settlement of raft according to tunneling. The effect of tunnel depth, soil consistency and spacing between double tunnels is studied. By increasing the soil cover above the tunnel crown, the settlement and bending moment of raft increases regardless the relative density of surrounding soil.

Abstract Background To introduce the surgical technique and our team’s extensive experience with tunnel method in laparoscopic adrenalectomy. Methods From July 2019 to June 2022, we independently designed and conducted 83 cases of " Tunnel Method Laparoscopic Adrenalectomy,” a prospective study. There were 45 male and 38 female patients, ages ranged from 25 to 73 years(mean: 44.6 years).The cases included 59 adrenal cortical adenomas, 9 pheochromocytomas, 6 cysts, 4 myelolipomas, 1 ganglioneuroma, and 4 cases of adrenal cortical hyperplasia. In terms of anatomical location, there were 39 cases on the left side, 42 on the right side, and 2 bilateral cases. Tumor diameters ranged from 0.6 to 5.9 cm(mean: 2.9 cm). Utilizing ultrasound monitoring, percutaneous puncture was made either directly to the target organ or its vicinity, and the puncture path was manually marked. Then, under the direct view of a single-port single-channel laparoscope, the path to the target organ in the retroperitoneum or its vicinity was further delineated and separated. This approach allowed for the insertion of the laparoscope and surgical instruments through the affected adrenal gland, thereby separating the surface of the target organ to create sufficient operational space for the adrenalectomy. Results All 83 surgeries were successfully completed. A breakdown of the surgical approach reveals that 51 surgeries were done using one puncture hole, 25 with two puncture holes, and 7 with three puncture holes. The operation time ranged from 31 to 105 min (mean: 47 min), with a blood loss of 10 to 220mL (mean: 40 mL). Notably, there were no conversions to open surgery and no intraoperative complications. Postoperative follow-up ranged from 6 to 28 months, during which after re-examination using ultrasound, CT, and other imaging methods, there were no recurrences or other complications detected. Conclusions The completion of the tunnel method laparoscopic adrenalectomy represents a breakthrough, transitioning from the traditional step-by-step separation of retroperitoneal tissues to reach the target organ in conventional retroperitoneoscopic surgery. This method directly accesses the target organ, substantially reducing the damage and complications associated with tissue separation in retroperitoneoscopic surgery, As a result, it provides a new option for minimally invasive surgery of retroperitoneal organs and introduces innovative concepts to retroperitoneoscopic surgery.

Abstract Background The concept of a financial scarcity mindset has raised much attention as an explanation for poor decision-making and dysfunctional behavior. It has been suggested that financial scarcity could also impair dietary behavior, through a decline in self-control. Underlying cognitive mechanisms of tunneling (directing attention to financial issues and neglecting other demands), cognitive load (a tax on mental bandwidth interfering with executive functioning) and time orientation (a shift towards a present time horizon, versus a future time horizon) may explain the association between financial scarcity and self-control related dietary behavior. The current scoping review gathers recent evidence on how these mechanisms affect dietary behavior of people experiencing financial scarcity. It builds on a theoretical framework based on insights from behavioral economics and health psychology. Methods A literature search was executed in six online databases, which resulted in 9.975 papers. Search terms were tunneling, cognitive load and time orientation, financial scarcity, and dietary behavior. Screening was performed with ASReview, an AI-ranking tool. In total, 14 papers were included in the scoping review. We used PRISMA-ScR guidelines for reporting. Results Limited evidence indicates that a scarcity mindset could increase tunneling, through attentional narrowing on costs of food, which then directly impacts dietary behavior. A scarcity mindset involves experiencing financial stress, which can be understood as cognitive load. Cognitive load decreases attentional capacity, which could impair self-control in dietary choices. Financial scarcity is related to a present time orientation, which affects dietary choices by shifting priorities and decreasing motivation for healthy dietary behavior. Conclusions A scarcity mindset affects dietary behavior in different ways. Tunneling and a shift in time orientation are indicative of an attentional redirection, which can be seen as more adaptive to the situation. These may be processes indirectly affecting self-control capacity. Cognitive load could decrease self-control capacity needed for healthy dietary behavior because it consumes mental bandwidth. How a changing time orientation when experiencing financial scarcity relates to motivation for self-control in dietary behavior is a promising theme for further inquiry.