High Figure Research Articles

On the improved RF performance of step field plate LDMOS transistor

This paper presents an analysis of the Step Field Plate Laterally Diffused Metal Oxide Semiconductor (SFP LDMOS) structure for improved high power and RF performance. The proposed structure is cost-effective, CMOS integrable, and has a high power figure of merit (FoM) due to its high off-state breakdown voltage (BVDS,off) and low specific on-resistance (Rsp). Significant improvement in frequency behavior is observed, as demonstrated by the flatter trans-conductance (gm), 12.5x lower gate-to-drain capacitance (Cgd), 2.5x lower gate-to-source capacitance (Cgs), and lower output conductance (gds). Single tone and double tone analyses are performed on an RF PA circuit implemented in TCAD. Results show ∼5 dBm higher output power (Pout), ∼6 dB higher power gain, and 46% higher drain efficiency (η), which are attributed to ∼1.9x lower drain-to-source capacitance (Cds) and ∼15 dBm lower magnitude of third-order intermodulation distortion due to lower third order derivative of drain current (ID). The paper also explains the device physics behind these observations.

Achieving High Isotropic Figure of Merit in Cd and in Codoped Polycrystalline SnSe.

Here, we combined Cd and In codoping with a simple hydrothermal synthesis method to prepare SnSe powders composed of nanorod-like flowers. After spark plasma sintering, its internal grains inherited well the morphological features of the precursor, and the multiscale microstructure included nanorod-shaped grains, high-density dislocations, and stacking faults, as well as abundant nanoprecipitates, resulting in an ultralow thermal conductivity of 0.15 W m-1 K-1 for the synthesized material. At the same time, Cd and In synergistically regulated the electrical conductivity and Seebeck coefficient of SnSe, leading to an enhanced power factor. Among them, Sn0.94Cd0.03In0.03Se achieved a peak ZT of 1.50 parallel to the pressing direction, representing an 87.5% improvement compared with pure SnSe. Notably, the material possesses isotropic ZT values parallel and perpendicular to the pressing direction, overcoming the characteristic anisotropy in thermal performance observed in previous polycrystalline SnSe-based materials. Our results provide a new strategy for optimizing the performance of thermoelectric materials through structural engineering.

DFT study of the half‐metallic variant perovskites A2OsX6 (A = Rb/Cs; X = Cl/Br) for spintronic and thermoelectric applications

AbstractWe present our results of the spin‐polarized calculations on the structural, magneto‐electronic, thermodynamic, and thermoelectric properties of vacancy‐ordered double perovskites A2OsX6 (A = Rb/Cs; X = Cl/Br). We utilized the Wu‐Cohen generalized gradient approximation (Wu‐GGA) and the mBJ scheme to determine a more reliable electronic structure. The compounds exhibit negative formation energy, suitable tolerance factor, and a stable phonon spectrum, indicating their stability. The compounds show half‐metallicity, acting as semiconductors with direct band gaps between 2 and 3 eV in the spin‐up orientation while metallic in the spin‐down. Each compound shows a total spin magnetic moment of 2.00 μB per formula unit, with Os‐t2g states contributing the most (~1.5 μB). The computed thermoelectric coefficient indicates the usability of these compounds across a wide temperature range (200–800 K) with high electrical conductivity and low electronic thermal conductivity. The compounds exhibit high Seebeck coefficient and figure of merit (ZT), making them suitable for thermoelectric applications. With ferromagnetic and half‐metallic characteristics, these compounds could be promising candidates for spintronics, thermoelectronic, and data storage applications.

Outcomes of Flexibility Sport Athletes With Borderline Hip Dysplasia After Hip Arthroscopy for Femoroacetabular Impingement Syndrome: A Propensity-Matched Analysis at Minimum 2-Year Follow-up

Background: Hip arthroscopy has proved successful in treating femoroacetabular impingement syndrome (FAIS) in patients with and without borderline hip dysplasia (BHD). Despite a high prevalence of BHD in patients who participate in sports with high flexibility requirements, a paucity of literature evaluates the efficacy of hip arthroscopy in treating FAIS in flexibility sport athletes with BHD. Purpose: To compare minimum 2-year patient-reported outcomes (PROs) and achievement of clinically significant outcomes in flexibility sport athletes with BHD undergoing primary hip arthroscopy for FAIS with capsular plication with results in flexibility sport athletes without dysplasia. Study Design: Cohort study; Level of evidence, 3. Methods: Data were prospectively collected for patients undergoing primary hip arthroscopy for FAIS with BHD, defined as a lateral center-edge angle of 18° to 25°, who reported participation in a sport with a high flexibility requirement, including dance, gymnastics, figure skating, yoga, cheerleading, and martial arts, according to previous literature. These patients were matched 1:2 to flexibility sport athletes without dysplasia, controlling for age, sex, and body mass index. Preoperative and minimum 2-year postoperative PROs were collected and compared between groups. Cohort-specific minimal clinically important difference and patient acceptable symptom state achievement was compared between groups. Results: In total, 52 flexibility sport athletes with BHD were matched to 104 flexibility sport athletes without BHD. Both groups showed similar sport participation (P = .874) and a similar level of competition (P = .877). Preoperative lateral center-edge angle (22.2°± 1.6° vs 31.5°± 3.9°; P < .001) and Tönnis angle (10.9°± 3.7° vs 5.8°± 4.4°; P < .001) differed between groups. Capsular plication was performed in all cases. Both groups achieved significant improvement in all PROs (P < .001) with no differences in postoperative PROs between groups (P≥ .147). High minimal clinically important difference (BHD group: 95.7%; control group: 94.8%) and patient acceptable symptom state (BHD group: 71.7%; control group: 72.2%) achievement for any PRO was observed with no differences between groups (P≥ .835). Conclusion: Flexibility sport athletes with BHD achieved similar outcomes as those of flexibility sport athletes without BHD after hip arthroscopy for FAIS with capsular plication.

Modelling and design of fiber optic Fabry-Pérot accelerometer with high figure merit

The Fabry-Pérot (F-P) accelerometer model with a high figure of merit is proposed, and the corresponding accelerometer is designed and experimentally researched. Theoretical analysis shows that this accelerometer is independent of the encapsulated optical fiber stiffness and its sensitivity can be enormously improved. Meanwhile, the method of wavelength demodulation is adopted and the figure of merit is introduced to evaluate the comprehensive Characteristic of the accelerometer. The results of the experiment showed that the accelerometer has a good response, its flat range is 10 Hz to 280 Hz, the corresponding sensitivity is 22.57 nm/G to 35.55 nm/G, and the cross sensitivity is less than 3.16 dB. The figure of merit is up to 10918.77 nm·Hz/G, the comprehensive response characteristics indicate that the sensor has good technical indexes. It not only has ultra-high sensitivity, but also has miniaturization potential.

UTERINE SCAR AND REPEAT PREGNANCY

According to the Ministry of Health for 2022, we registered 932.2 thousand births, which is the highest figure since independence. The total fertility rate (number of births per 1,000 inhabitants) was 26.2 –in 2022, which falls into the category of countries with a “moderately high” fertility rate. The purpose of the study was to assess the condition of the postoperative scar in women who underwent cesarean section. The study is based on a clinical and laboratory examination of 103 women of reproductive age with a history of one uterine scar, who was under observation in the department of Obstetrics and Gynecology of the multidisciplinary clinic of Samarkand State Medical University for the period from 2020 to 2022. Thus, it can be noted that there is an improvement in the concentration of type XXVI collagen in postpartum women who have undergone a full course of rehabilitation measures after childbirth, which, in turn, indicates abetter restoration of damage to the genital organs, including the condition of the scar.

Investigation of the Structural, Mechanical, Electronic, Magnetic, and Thermoelectric Properties of Half Heusler Alloys ZrMnX (X = As, Sb, Te): A DFT‐Based Simulation

AbstractThis study investigates the structural, mechanical, electronic, magnetic, and thermoelectric properties of ZrMnX (X = As, Sb, Te) half Heusler alloys using spin‐polarized density functional theory (SPDFT) with WIEN2K code using full potential linearized augmented plane wave(FP‐ LAPW) technique. Results indicate the ferromagnetic phase’s stability over the non‐magnetic phase in all three alloys. Band structures and density of states highlight the half‐metallic nature of ZrMnX. These alloys exhibit mechanical stability, ductility, and directional properties. Magnetic moments align with the Slater–Pauling rule. Thermoelectric properties, including Seebeck coefficient, electrical and thermal conductivity, and thermoelectric figure of merit, are evaluated using semi‐classical Boltzmann theory. The Seebeck coefficient values for ZrMnX (X = As, Sb, Te) are 144.7, 123.3, and −182.6 µV K−1, respectively at 1200 K with corresponding highest figure of merit 1.0, 0.7, and 1.78. These findings suggest the suitability of these alloys for spintronic devices and high‐temperature thermoelectric applications due to their observed spin‐polarized character and high figure of merit.

Analysis of Accident Risk Points (Black Spots) on the Bubutan – Perak Barat Road Section Surabaya

According to the traffic accident data from the Traffic Accident Unit of the Tanjung Perak Port Police and the Traffic Accident Unit of the Dukuh Pakis Police in Surabaya City in 2020-2022, traffic accidents that occurred on the Bubutan Road - West Perak Road section experienced an increase in the number of traffic accidents. The total details in 2021 were 13 incidents, in 2022 there was an increase to 17 incidents, besides that, the material losses incurred in 2022 had the highest figure, which amounted to IDR 46,000,000. So it is necessary to analyze the accident-prone points on the road section. The method used are AEK (Accident Equivalent Number), IPA (Importance Performance Analysis) method, and calculation of free flow speed, traffic volume analysis, and side obstacle analysis. Based on the analysis of accident-prone areas using the AEK method, it is known that the upper control limit value is 36.07 where Jalan Perak Barat has an AEK value above the BKA value in 2021 of 37, then in 2022 of 40. Jalan Perak Barat has an average traffic volume of 434.47 smp / hour, with a moderate level of side obstacles, but has a free flow speed that exceeds the planned speed. One of the factors causing traffic accidents on Jalan Perak Barat is the driver of a vehicle traveling at high speed, so rumble strip planning and road facility rejuvenation are recommended.

A 26-28 GHz, Two-Stage, Low-Noise Amplifier for Fifth-Generation Radio Frequency and Millimeter-Wave Applications.

This paper presents a high-gain low-noise amplifier (LNA) operating at the 5G mm-wave band. The full design combines two conventional cascode stages: common base (CB) and common emitter (CS). The design technique reduces the miller effect and uses low-voltage supply and low-current-density transistors to simultaneously achieve high gain and low noise figures (NFs). The two-stage LNA topology is analyzed and designed using 0.25 µm SiGe BiCMOS process technology from NXP semiconductors. The measured circuit shows a small signal gain at 26 GHz of 26 dB with a gain error below 1 dB on the entire frequency band (26-28 GHz). The measured average NF is 3.84 dB, demonstrated over the full frequency band under 15 mA current consumption per stage, supplied with a voltage of 3.3 V.

A High Gain Concurrent Dual-band Low-Noise Amplifier in 130-nm BiCMOS Technology

This paper presents a fully integrated concurrent 15/30-GHz dual-band low-noise amplifier (LNA). The proposed concurrent LNA IC is designed and simulated in 130-nm BiCMOS technology. The new passive LC notch filter is proposed to realize high gain and low noise figure over dual-band frequency, simultaneously. The simulated BiCMOS LNA IC has exhibited peak gains of 30.1/23.7 dB at 15/30-GHz, respectively, with 20-mW power consumption from 1-V supply. The concurrent dual-band LNA achieves noise figure of 2.2/2.9-dB and IIP3 of -18.2/-8.8 dBm at the respective passbands. Therefore, the proposed dual band concurrent LNA IC is applicable to front-end RF receivers for Ku-Band and Ka-Band systems.

Ultrasonic fortification of interfiber autohesive contacts in meltblown nonwoven materials

Autohesion is a unique class of adhesion that enables the bonding of two identical surfaces by establishing intimate contact at interfaces. Creating intimacy between two identical surfaces poses a challenging task, often constrained by the presence of surface roughness and chemical heterogeneity. To surmount this challenge, we document a variety of autohesive traits in polypropylene-based meltblown nonwovens, accomplished through a facile, scalable, energy-efficient, and cost-effective ultrasonic bonding process. The mean work of autohesion for a single polypropylene bond, serving as a figure of merit, has been computed by extending the classical Johnson−Kendall−Roberts (JKR) theory by factoring in peel strength along with key fiber and structural parameters of nonwoven materials. Achieving a high figure of merit in ultrasonically bonded nonwovens hinges on the synergistic interplay of key process parameters, including static force, power, and welding speed, with the fiber and structural properties acting in concert. In this regard, peel-off force analysis has also been conducted on a series of twenty-seven ultrasonically bonded meltblown nonwovens prepared using a 33 full factorial design by systematically varying process parameters (static force, power, and welding speed) across three levels and extension rate. X-ray microcomputed tomography (microCT) analysis has been performed on select ultrasonically bonded nonwoven samples to discern their bulk characteristics. A broad spectrum of mean work of autohesion for a single polypropylene bond, ranging from 1.88 to 9.93 J/m², has been ascertained by modulating key process parameters.

Methodology of Monitoring Social and Economic Development in Regional Economic Systems (illustrated by the Altay Area)

The article studies such notions as ‘methodology’, ‘regional economic system’, ‘monitoring of regional economic system’. The author provides his own definition of the notion ‘monitoring of social and economic development of regional economic systems’ and highlighted 6 key stages of its conducting: organizational, information collection, information preparation, data analysis, forecasting and modeling, conclusion preparation and their publication. As an example of monitoring the author chose a regional program, which affects directly the development of social component of the regional economic system, in particular, the achievement of high standard of living at the expense of cutting poverty rate and raising real income of the population. The author conducted analysis by the proposed methodology using open sources of information. In this analysis he used the method of standard values with estimation of the program implementation efficiency. On the basis of monitoring results a conclusion was drawn about the efficiency of the given regional program in the Altay area in view of high figures of efficiency by set goals and indicators of the regional program.

High efficient net gain and low noise figure based vertical cavity semiconductor optical amplifiers for wavelength division multiplexing applications

Abstract This paper has demonstrated the high efficient net gain and low noise figure based vertical cavity semiconductor light amplifiers for wavelength division multiplexing applications. Previous study on the chip reflective gain variations versus SOA current under temperature effects is clarified. We have transferred light semiconductor amplifiers for wavelength multiplexing schemes applications. Amplifier output power is demonstrated with bias current and amplifier active layer region length variations based input signal power of 3, 6.5, 10 dBm, 1550 nm wavelength and optimum amplifier confinement factor of 0.45. The amplifier output noise variations are clarified against the bias current and amplifier active layer region width variations based input signal power of 3, 6.5, 10 dBm, 1550 nm wavelength and optimum amplifier confinement factor of 0.45. The output OSNR variations are studied clearly and deeply against the bias current and amplifier active layer region length variations based input signal power of 3, 6.5, 10 dBm, 1550 nm wavelength and optimum amplifier confinement factor of 0.45. The signal loss is demonstrated versus both active layer width/length and temperature based optimum 30 % gallium core dopant ratio and 28 % arsenide cladding dopant ratio at optimum input signal power of 10 dBm, 1550 nm wavelength and optimum amplifier confinement factor of 0.45. SOA amplifier output power can be enhance with the management of both bias current and input signal power and the reduction of active amplifier length. The amplifier output noise can be enhance with the management of both bias current and input signal power and the reduction of active amplifier width. Output OSNR system can be improved with the management of both bias current and input signal power and the reduction of active amplifier length. The SOA amplifier gain can be improved with the management of both bias current and input signal power and the reduction of active amplifier length. The SOA amplifier noise figure can be improved with the management of both bias current and input signal power and the reduction of active amplifier width. The signal loss can be controlled and managed by adjusting optimum 30 % gallium core dopant ratio and 28 % arsenide cladding dopant ratio, optimum active layer/with and the presence of room temperature.

Giant Deformation Induced Staggered-Layer Structure Promoting the Thermoelectric and Mechanical Performance in n-Type Bi2(Te, Se)3.

Bismuth telluride has long been recognized as the most promising near-room temperature thermoelectric material for commercial application; however, the thermoelectric performance for n-type Bi2(Te, Se)3-based alloys is far lagging behind that of its p-type counterpart. In this work, a giant hot deformation (GD) process is implemented in an optimized Bi2Te2.694Se0.3I0.006+3 wt%K2Bi8Se13 precursor and generates a unique staggered-layer structure. The staggered-layered structure, which is only observed in severely deformed crystals, exhibits a preferential scattering on heat-carrying phonons rather than charge-carrying electrons, thus resulting in an ultralow lattice thermal conductivity while retaining high-weight carrier mobility. Moreover, the staggered-layer structure is located adjacent to the van der Waals gap in Bi2(Te, Se)3 lattice and is able to strengthen the interaction between anion layers across the gap, leading to obviously improved compressive strength and Vickers hardness. Consequently, a high peak figure of merit ZT of ≈ 1.3 at 423 K, and an average ZT of ≈ 1.2 at 300-473 K can be achieved in GD sample. This study demonstrates that the GD process can successfully decouple the electrical and thermal transports with simultaneously enhanced mechanic performance.

Band gap and optical property modulation under pressure in vacancy-ordered double perovskite Cs[formula omitted]SeCl[formula omitted

This paper presents a comprehensive study on the effect of pressure on the structural, elastic, electronic, thermoelectric, and optical properties of vacancy ordered double perovskite Cs2SeCl6, using first principle calculations. Results show that the lattice constant and band gap of Cs2SeCl6 decrease with increasing hydrostatic pressure from 0 to 140 GPa. The band gap value decreases from 2.94 eV to 1.62 eV and the electronic structure analysis reveals an indirect band gap nature. The elastic constants, Poisson’s ratio, and Pugh’s ratio indicate the mechanical stability and ductile behavior of Cs2SeCl6. Furthermore, due to its suitable band gap and enhanced light absorption with increasing pressure, Cs2SeCl6 exhibits potential as a photoelectric absorption layer material for high-pressure solar cell applications. Moreover, Cs2SeCl6 exhibits high electrical conductivity and low thermal conductivity, resulting in a high figure of merit and promising thermoelectric applications.

High Thermoelectric Performance of n-type BiTeSe-Based Composites Incorporated with Both Inorganic and Organic Nanoinclusions.

N-type Bi2Te2.7Se0.3 (BTS) alloy has relatively low thermoelectric performance as compared to its p-type counterpart, which restricts its widespread applications. Herein, we designed and prepared a novel composite system, which consists of an n-type BTS matrix incorporated with both inorganic and organic nanoinclusions. The results indicate that the thermopower of the composite samples can be enhanced by more than 19% upon incorporating inorganic nanophase AgBi3S5 (ABS) due to the energy-dependent carrier scattering, which ensures a high power factor. On the other hand, further incorporation of organic nanophase polypyrrole (PPy) can drastically reduce its lattice thermal conductivity owing to the strong scattering of mid- and low-frequency phonons at these nanoinclusions. As a result, high figures of merit ZTmax = 1.3 at 348 K and ZTave = 1.17 (300-500 K) are achieved with improved mechanical properties in BTS-based composites incorporated with 1.5 wt % ABS and 0.5 wt % PPy, demonstrating that the incorporation of both inorganic and organic nanoinclusions is an effective way to improve its thermoelectric performance.

Involvement of school-age children of Volyn oblast in the all- Ukrainian children and youth military-patriotic game «Sokil» («Dzhura»)

In the conditions of a full-scale war, one of the main tasks of the educational process is to strengthen the work on national-patriotic education of children and youth by analyzing their involvement in the military-patriotic game «Sokil» («Dzhura») and, subsequently, diversifying the form of work on military-patriotic education. This article is devoted to the theme of the organization of the Game and the dynamics of the popularity for all-Ukrainian children and youth military-patriotic game «Sokil» («Dzhura») in Volyn. Research methods: analysis and synthesis of scientific and methodological literature, generalization of scientists' research and systematization of the results, theoretical modeling method, methods of mathematical statistics.&#x0D; During the year, the number of students engaged in «Dzhura» ranged from approximately 1,200 to 1,660 in 2019-2023. The highest figure (1,669 people) was recorded in 2019, the lowest (1,205 people) in 2022. This is due to the spread of the COVID- 19 pandemic and the beginning of a full-scale war. According to the age criteria, during the studied years, students of middle school age participated the most (69.9-85.1%), the least - older students (1.8-9.1%); the younger generation occupies the second position (13.2-24.9%). It should be noted that a small proportion of the involved youth aged 15-17 may potentially not contribute to the popularization of the Game, since it is they who are being trained as "kozachata" (small cossacks) for novices. Conclusion. It was determined that the all-Ukrainian children and youth military-patriotic game «Sokil» («Dzhura») in Volyn oblast is carried out systematically and at a high level, attracting participants in three age categories. This is an average of 0.87% of the total number of all schoolchildren in oblast.

N-DMBI Doping of Carbon Nanotube Yarns for Achieving High n-Type Thermoelectric Power Factor and Figure of Merit.

The application of carbon nanotube (CNT) yarns as thermoelectric materials for harvesting energy from low-grade waste heat including that generated by the human body, is attracting considerable attention. However, the lack of efficient n-type CNT yarns hinders their practical implementation in thermoelectric devices. This study reports efficient n-doping of CNT yarns, employing 4-(1, 3-dimethyl-2, 3-dihydro-1H-benzimidazole-2-yl) phenyl) dimethylamine (N-DMBI) in alternative to conventional n-dopants, with o-dichlorobenzene emerging as the optimal solvent. The small molecular size of N-DMBI enables highly efficient doping within a remarkably short duration (10s) while ensuring prolonged stability in air and at high temperature (150°C). Furthermore, Joule annealing of the yarns significantly improves the n-doping efficiency. Consequently, thermoelectric power factors (PFs) of 2800, 2390, and 1534µWm-1K-2 are achieved at 200, 150, and 30°C, respectively. The intercalation of N-DMBI molecules significantly suppresses the thermal conductivity, resulting in the high figure of merit (ZT) of 1.69×10-2 at 100°C. Additionally, a π-type thermoelectric module is successfully demonstrated incorporating both p- and n-doped CNT yarns. This study offers an efficient doping strategy for achieving CNT yarns with high thermoelectric performance, contributing to the realization of lightweight and mechanically flexible CNT-based thermoelectric devices.

Structural, electronic, optical, elastic, mechanical, thermodynamic, and thermoelectric properties of lead-free and environmentally friendly CsSnX3 (X = Cl, Br) perovskites

In this study, we systematically examined the physical properties of CsSnX3 (X = Cl, Br) by employing the (FP-LAPW) method within the (GGA) and GGA + mBJ approximations. The investigated compounds exhibit direct bandgap semiconducting with an ionic-covalent mixture in CsSnX3 bonds. Notably, CsSnCl3 and CsSnBr3 exhibit exceptional light absorption and optical conductivity, making them appropriate for a particular application. Elastic constants of compounds and different moduli are determined for the first time. Considering the thermodynamic model, perovskite materials consistently display thermodynamic properties such as heat capacity, Debye temperature, Grüneisen constant for a range of pressures and temperatures. The calculations of transport properties by using BoltzTrap code reveals a high figure of merit close to unity for CsSnX3 (Cl, Br) at room temperature, highlighting their potential for thermoelectric applications. Overall, CsSnX3 (Cl, Br) perovskite exhibit remarkable physical properties and environmental compatibility, positioning them as up-and-coming candidates for optoelectronic and thermoelectric applications.

Parallel self-avoiding walks for a low-autocorrelation binary sequences problem

A low-autocorrelation binary sequences problem with a high figure of merit factor represents a formidable computational challenge. An efficient parallel computing algorithm is required to reach the new best-known solutions for this problem. Therefore, we developed the sokolskew solver for the skew-symmetric search space. The developed solver takes the advantage of parallel computing on graphics processing units. The solver organized the search process as a sequence of parallel and contiguous self-avoiding walks and achieved a speedup factor of 387 compared with lssOrel, its predecessor. The sokolskew solver belongs to stochastic solvers and cannot guarantee the optimality of solutions. To mitigate this problem, we established the predictive model of stopping conditions according to the small instances for which the optimal skew-symmetric solutions are known. With its help and 99% probability, the sokolskew solver found all the known and seven new best-known skew-symmetric sequences for odd instances from L=121 to L=223. For larger instances, the solver cannot reach 99% probability within our limitations, but it still found several new best-known binary sequences. We also analyzed the trend of the best merit factor values, and it shows that as sequence size increases, the value of the merit factor also increases, and this trend is flatter for larger instances.