Technical Physics Letters最新文献

{"title":"Comprehensive Investigation of Gate Scaling and Field-Plate Effects in InAlGaN/GaN HEMTs for High-Power Applications","authors":"P. Gowtham,&nbsp;Sangeeta Singh,&nbsp;C. Jeevanantham,&nbsp;N. Vigneshwari","doi":"10.1134/S1063785026600699","DOIUrl":"10.1134/S1063785026600699","url":null,"abstract":"<p>This work investigates the impact of gate-length (<i>L</i>_G) and gate-to-source spacing (<i>L</i>_GS) scaling on the electrical, RF, and breakdown characteristics of a quaternary In_0.78Al_0.13Ga_0.09N/GaN HEMT employing a sapphire substrate and gate field-plate architecture. Owing to the enhanced spontaneous and piezoelectric polarization associated with the In-rich quaternary barrier, a deep quantum well is formed at the heterointerface, leading to strong 2DEG confinement and improved carrier transport. Detailed TCAD simulations are performed to analyze the influence of geometric scaling on transfer characteristics, transconductance, capacitances, electric-field distribution, cutoff frequency, and breakdown behavior. The optimized structure exhibits a maximum <i>I</i>_D of approximately 1.08 A/mm, a peak transconductance of 0.46 S/mm, ultra-low off-state leakage current in the order of 10⁻¹⁶ A/mm, and an <i>I</i>_on/<i>I</i>_off ratio exceeding 10¹⁵. Furthermore, a peak <i>f</i>_T of 40 GHz and a maximum breakdown voltage of 497 V are achieved through appropriate optimization of gate length and field-plate dimensions. The electrostatic potential and electric-field analyses reveal improved field redistribution and reduced field crowding, contributing to enhanced reliability and high-voltage operation. The obtained results demonstrate that the proposed In_0.78Al_0.13Ga_0.09N/GaN HEMT offers an excellent balance between high-frequency performance and breakdown capability for next-generation RF and power electronic applications.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":"52 10","pages":"521 - 534"},"PeriodicalIF":0.8,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149250465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Benchmarking a Long-Range Interacting Fermionic Model on IBM Heron r2 Processors: Zero-Noise Extrapolation versus Symmetry-Based Post-Selection on a 6-Qubit Ring Testbed","authors":"A. G. Kiiamov,&nbsp;D. A. Tayurskii","doi":"10.1134/S1063785026600687","DOIUrl":"10.1134/S1063785026600687","url":null,"abstract":"<p>We benchmark two error-mitigation strategies for digital quantum simulation of a long-range interacting fermionic model on IBM Heron r2 superconducting processors. The testbed is a minimal exactly solvable system—two spinless electrons on a 6-site ring with repulsive <span>({text{1/}}r)</span> chord-distance Coulomb interactions—whose ground state exhibits a smooth Wigner-dimer localization crossover quantified by the antipodal occupation probability <span>({P_3}(U))</span>. Circuit parameters of a particle-number-conserving variational ansatz are optimized classically; the quantum processors execute only final energy and configuration measurements. We compare (i) zero-noise extrapolation (ZNE) applied to the full Hamiltonian with (ii) a hybrid estimator in which the off-diagonal kinetic energy is measured with ZNE while the diagonal interaction energy is reconstructed from particle-number post-selected bitstrings. Across eight interaction strengths <span>(U{text{/}}t in [5,75])</span>, five measurement sessions on two devices (ibm_fez, ibm_marrakesh), and three circuit depths, the hybrid estimator achieves, in the interacting regime <span>(U{text{/}}t geqslant 15)</span>, relative ground-state energy errors of 4.3–14% that decrease systematically with <span>(U)</span>—an order of magnitude better than full-Hamiltonian ZNE (29–85%)—and reproduces the localization crossover in <span>({P_3}(U))</span>. At <span>(U{text{/}}t = 5)</span>, where <span>({E_0} approx 0.08{kern 1pt} t)</span> renders the relative error ill-conditioned, the absolute hybrid error is <span>(0.62{kern 1pt} t)</span>, in line with the rest of the scan. A depth scan at fixed <span>(U{text{/}}t = 45)</span> shows that the shallowest circuit wins despite a 1.8% ansatz expressivity penalty, quantifying the expressivity–noise trade-off. Shot-noise uncertainties, recovered exactly from per-noise-factor data, are below one percentage point in relative energy error for the hybrid estimator (versus 7–14 percentage points for ZNE at equal shot budget) and an order of magnitude smaller than the measured inter-session calibration spread. The exact variational bound <span>({E_{{text{exp}}}} geqslant {E_{{text{theory}}}})</span> is satisfied in all 27 full-Hamiltonian hardware energy measurements. All data were acquired with under nine minutes of QPU time on the free IBM Quantum Open Plan.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":"52 10","pages":"546 - 553"},"PeriodicalIF":0.8,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149250467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relaxation Processes in Track Membranes based on Polyvinylidene Fluoride","authors":"E. A. Volgina,&nbsp;A. A. Kononov,&nbsp;Y. I. Sotova,&nbsp;D. E. Temnov","doi":"10.1134/S1063785026600663","DOIUrl":"10.1134/S1063785026600663","url":null,"abstract":"<p>The work investigates relaxation processes in polyvinylidene fluoride (PVDF) films modified by ion irradiation with heavy ions ¹³²Xe²⁶⁺ followed by chemical etching. Dielectric spectroscopy and thermally stimulated depolarization methods were used for analysis, which made it possible to cover a wide frequency range from 10^–5 to 10⁶ Hz. Two relaxation processes were considered: α relaxation in the glass transition temperature region (<i>T</i>_g ≈ − 40°C) and α_c relaxation, which manifests itself near room temperature. After chemical etching, an additional relaxation process was detected at about −10°C, associated with the formation of relaxers on the pore surface. It was shown that changes in etching time and pore diameter significantly affect the intensity of relaxation processes.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":"52 10","pages":"535 - 545"},"PeriodicalIF":0.8,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149250584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Issue of Calculating the Friction Force of a Piston Compressor","authors":"R. E. Kobyl’skiy","doi":"10.1134/S1063785026600675","DOIUrl":"10.1134/S1063785026600675","url":null,"abstract":"<p>An important and relevant aspect of thermodynamic calculation of a piston compressor is considered, namely, calculation of friction forces acting in a row. The analysis showed that the discrepancy between the calculated and actual friction force values can reach up to 90%. This fact has a negative impact on the further calculation of the piston compressor, since the friction force is one of the components in the calculation of the total piston force. Existing methods for calculating friction force were analyzed, as a result of which all obtained results differ from the actual friction force by from 75 to 90%. An engineering calculation method was proposed that made it possible to reduce the error in calculating friction forces by 50–60%.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":"52 10","pages":"554 - 557"},"PeriodicalIF":0.8,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149250468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Testing a Piston Household Compressor with Forced Suction","authors":"R. E. Kobyl’skiy","doi":"10.1134/S106378502660081X","DOIUrl":"10.1134/S106378502660081X","url":null,"abstract":"<p>The history of the development of forced supercharging of piston compressors is briefly presented. Simplifying schemes and main results of previous authors are presented. Based on the experience of previous authors, a scheme for forced supercharging of a household piston compressor was proposed and the existing experimental stand was modified in order to increase its energy efficiency. By using forced supercharging, it was possible to increase the compressor’s performance (the delivery efficiency increased by an average of 9%), while at the same time it was possible to reduce the specific energy consumption by an average of 7.6%. The forced-pressure boost system turned out to be simple to implement and does not require the installation of a large range of additional equipment and constant monitoring of process parameters, as was implemented in previous works.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":"52 10","pages":"565 - 569"},"PeriodicalIF":0.8,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149250583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Moisture and Heat Resistance of Flexible Thin-Film GaAs Solar Cell Modules","authors":"Guorui Sun","doi":"10.1134/S1063785026600821","DOIUrl":"10.1134/S1063785026600821","url":null,"abstract":"<p>Long-term exposure to high-temperature and high-humidity environments inevitably causes performance degradation of flexible thin-film gallium arsenide (GaAs) solar cell modules, which poses a critical challenge for solar-powered unmanned aerial vehicles deployed in southern coastal regions of China. This work evaluates the moisture and heat resistance of flexible GaAs modules with different encapsulation designs via accelerated aging tests. Two sample groups were fabricated with identical ethylene-tetra-fluoro-ethylene (ETFE) front sheets and polyolefin elastomer (POE) encapsulant, but with distinct backsheet materials: polyimide (PI) for Group A and polyethylene terephthalate (PET) for Group B. All samples were exposed to 85 °C / 85% relative humidity conditioning following the IEC 62108 standard, and their electrical performance and defect evolution were characterized at 0, 72, 144 and 168 h. The results indicate that water vapor penetrates the encapsulation and reacts with metal dangling bonds in the epitaxial layer of inverted metamorphic (IMM) triple-junction cells, forming highly conductive oxides that induce local micro-short circuits across P–N junctions and trigger electrical degradation. After 168 h of humidity-heat exposure, PI-encapsulated modules show a maximum efficiency drop of nearly 6%, which is significantly higher than that of PET-encapsulated modules. Electroluminescence imaging confirms that defect dark spots initiate and expand from cell edges, consistent with edge-dominated water vapor ingress. Based on the identified degradation mechanism, two improvement pathways are proposed: adopting low-water-vapor-transmission encapsulation materials with widened edge seals to reduce moisture ingress, and optimizing epitaxial growth to minimize dangling bond density for enhanced intrinsic cell robustness. The findings provide practical guidance for reliability design of flexible GaAs solar modules intended for long-term storage in hot and humid climates.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":"52 10","pages":"558 - 564"},"PeriodicalIF":0.8,"publicationDate":"2026-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149250466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reproducibility of Velocity Profiles in Gas Flow Metering Units under Complex Gasdynamic Conditions","authors":"N. S. Dushin,&nbsp;I. V. Nikiforov,&nbsp;A. A. Valeev","doi":"10.1134/S1063785026700938","DOIUrl":"10.1134/S1063785026700938","url":null,"abstract":"<p>The efficiency of four modifications of flow conditioners in terms of smoothing velocity profiles and ensuring their reproducibility with varying flow history and turbulence intensity at low Reynolds numbers was experimentally studied. The relevance of the work is due to the problem of increasing the accuracy of gas flow measurement in complex gas-dynamic conditions, especially in the region of laminar–turbulent transition. An approach has been identified that allows for the leveling of velocity profile deformations in a wide range of flow histories with a flow turbulence level not exceeding 14% and down to a lower Reynolds number value of 943.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":"52 9","pages":"472 - 475"},"PeriodicalIF":0.8,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149222772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Secondary Flows and Hydraulic Resistance in a Rectangular Channel with Spatially Inhomogeneous Discrete Roughness","authors":"R. R. Shakirov,&nbsp;I. A. Davletshin,&nbsp;N. I. Mikheev","doi":"10.1134/S1063785026700926","DOIUrl":"10.1134/S1063785026700926","url":null,"abstract":"<p>Spanwise heterogeneous surface roughness can induce secondary flows of Prandtl’s second kind, which significantly affect momentum and heat transfer. Despite a large number of numerical studies of such flows, experimental data remain rather limited. In this paper, an experimental study of turbulent flow in a rectangular channel with walls formed by alternating smooth sections and strips of discrete roughness is performed. The fields of mean velocities and turbulence characteristics are obtained using the SIV method, and the structure of secondary flows is reconstructed. Measurements of hydraulic resistance are carried out for various surface configurations and Reynolds numbers. It is shown that heterogeneous roughness leads to the formation of large-scale secondary flows in the form of counter-rotating vortices with a transverse velocity of up to 5% of the main flow velocity. A correlation between the intensity of secondary flows and the hydraulic resistance coefficient is revealed, indicating a significant role of secondary circulation in momentum transfer mechanisms in the channel.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":"52 9","pages":"476 - 483"},"PeriodicalIF":0.8,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149222773","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Monte Carlo Analysis of Ga2O3 Damage from Alpha Particle Radiation","authors":"Daotian Shi,&nbsp;Chuanyang Liu,&nbsp;Qing Sun,&nbsp;Jingjing Liu,&nbsp;Xinjiang Wang,&nbsp;Huakui Hu","doi":"10.1134/S1063785026600626","DOIUrl":"10.1134/S1063785026600626","url":null,"abstract":"<p>In this study, we used the Monte Carlo method to simulate the interaction of alpha particles with Ga₂O₃ and assess radiation damage. The findings show that alpha particles are primarily stopped by electrons, with ionization dominating energy dissipation, while phonon and vacancy‑related losses contribute negligibly. Over the investigated energy range, ionization loss increased with radiation energy, while both phonon and vacancy losses decreased. At a radiation energy of 2.05 MeV, ionization accounts for 99.41% of the total energy loss, while phonon excitation and vacancy formation contribute only 0.03 and 0.52%, respectively. As the radiation energy increased from 2.05 to 5.48 MeV, the peak energy absorbed by Ga and O atoms decreased from 0.81 and 0.84 eV to 0.62 eV, respectively. Alpha particles in Ga₂O₃ have a spatial distribution similar to a tadpole. The calculated maximum values were 0.0347 for displacement per atom (DPA), 1.63 × 10²¹ cm^–3 for V_Ga concentration, and 1.65 × 10²¹ cm^–3 for V_O concentration. These results demonstrate that alpha particle irradiation causes substantial damage in Ga₂O₃, posing a critical threat to both material integrity and device functionality.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":"52 9","pages":"493 - 500"},"PeriodicalIF":0.8,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149222571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Theoretical Estimation of the Heat Transfer Coefficient in a Plane Channel","authors":"N. D. Bogdanov,&nbsp;I. A. Davletshin","doi":"10.1134/S106378502670094X","DOIUrl":"10.1134/S106378502670094X","url":null,"abstract":"<p>The heat transfer coefficient in a plane channel was estimated theoretically. In the framework of assumptions made in the present research, a correlation in the form of Lyon’s integral was obtained for energy equation. It was employed for analytical estimation of heat transfer coefficient in laminar flows and liquid metal flows, in which molecular heat transfers prevail over turbulent one. The computational results comply with the literature.</p>","PeriodicalId":784,"journal":{"name":"Technical Physics Letters","volume":"52 9","pages":"467 - 471"},"PeriodicalIF":0.8,"publicationDate":"2026-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149222572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}