Cycle Ratio Research Articles

Low-Temperature ALD of SbOx /Sb2 Te3 Multilayers with Boosted Thermoelectric Performance.

Nanoscale superlattice (SL) structures have proven to be effective in enhancing the thermoelectric (TE) properties of thin films. Herein, the main phase of antimony telluride (Sb2 Te3 ) thin film with sub-nanometer layers of antimony oxide (SbOx ) is synthesized via atomic layer deposition (ALD) at a low temperature of 80 °C. The SL structure is tailored by varying the cycle numbers of Sb2 Te3 and SbOx . A remarkable power factor of 520.8 µW m-1 K-2 is attained at room temperature when the cycle ratio of SbOx and Sb2 Te3 is set at 1:1000 (i.e., SO:ST = 1:1000), corresponding to the highest electrical conductivity of 339.8 S cm-1 . The results indicate that at the largest thickness, corresponding to ten ALD cycles, the SbOx layers act as a potential barrier that filters out the low-energy charge carriers from contributing to the overall electrical conductivity. In addition to enhancing the scattering of the mid-to-long-wavelength at the SbOx /Sb2 Te3 interface, the presence of the SbOx sub-layer induces the confinement effect and strain forces in the Sb2 Te3 thin film, thereby effectively enhancing the Seebeck coefficient and reducing the thermal conductivity. These findings provide a new perspective on the design of SL-structured TE materials and devices.

Effect of electroacupuncture at "Jiaji" (EX-B2) on senescence of nucleus pulposus cells of degenerated lumbar intervertebral disc in rabbits.

To observe the effect of electroacupuncture (EA) at "Jiaji"(EX-B2) on body mass, motor function, expression of caveolin-1 (Cav-1) in nucleus pulposus cells and annulus fibrosus tissue, telomerase activi-ty, relative telomere length and different cell cycle ratio of nucleus pulposus cells in rabbits with intervertebral disc degeneration(IVDD), so as to investigate its mechanism underlying delaying senescence of the degenerated lumbar intervertebral disc nucleus pulposus cells. Twenty-five male New Zealand rabbits with mature bones were divided into control, sham operation, model, EA, and acupuncture groups, with 5 rabbits in each group. The IVDD model was established by inserting kirschner wires to the vertebral bone surface between the lumbar (L)4 and L5 vertebrae, followed by applying continuous axial pressure for 28 d. EA (2 Hz/15 Hz, 1-2 mA) or acupuncture (only insertion of acupuncture needles into bilateral EX-B2, but without electrical stimulation) was applied to bilateral EX-B2 for 20 min, once daily, 6 times a week for 4 weeks. The hindlimb locomotor function (locomotor score) was assessed by using Faden's and colleagues' methods. The general conditions of rabbits in each group were observed, and their body weight changes were measured every week. Nucleus pulposus cells were isolated using enzyme digestion method. After the treatment, the Cav-1 positive cell counts in nucleus pulposus cells and annulus fibrosus tissues were detected by immunohistochemistry, and the telomerase activity of nucleus pulposus cells was detected by PCR-ELISA. The relative telomere length of nucleus pulposus cells was measured by real-time quantitative polymerase chain reaction (real-time qPCR), and the cell cycle of nucleus pulposus was detected by flow cytometry. Compared with the sham operation group, the body mass from 4 to 11 week, locomotor score at 4, 7 and 11 week, telomerase activity, relative telomere length and the proportion of cells in G2/M phase of nucleus pulposus cells were significantly decreased (P<0.01), while Cav-1 positive cell counts of nucleus pulposus and annulus fibrosus tissue, and the proportion of nucleus pulposus cells in the G0/G1 phase considerably increased (P<0.01) in the model group. Relevant to the model group, the EA group rather than the acupuncture group had an increase in the body mass from 8 to 11 week, locomotor score at 11 week, telomerase activity, relative telomere length of nucleus pulposus cells, and the proportion of nucleus pulposus cells in G2/M phase (P<0.01), and a decrease in the Cav-1 positive cell counts of nucleus pulposus and annulus fibrosus tissue and the proportion of cells in G0/G1 phase (P<0.01). No significant differences were found between the model and acupuncture groups in all the indexes mentioned above. EA at EX-B2 has a bene-ficial effect in improving motor function in rabbits with IVDD, which may be related to its functions in reducing the expression of Cav-1 in nucleus pulposus cells and annulus fibrosus, improving cycle arrest, enhancing the telomerase activity and the relative telomere length of nucleus pulposus cells, delaying the senescence of nucleus pulposus cells of the degenerated lumbar intervertebral discs.

Real-time control suitable for feed distribution strategy based on ammonia introduced in SBR sub-cycle: Field experience and validation for pilot-scale single-stage deammonification

Feed distribution based on ammonium introduced in a sequencing batch reactor (SBR) was applied to a 24 m3 single-stage deammonification to treat reject water. With field experience, the conventional SBR exhibited limited adaptability to fluctuations in influent load. This study proposed a new approach capable of coping with the influent fluctuations. The pH and alkalinity were clustered as factors that affect the NRE, which was related to the ammonium behavior in the SBR sub-cycle. To establish the real-time control, the pH value, which has the highest correlation with them, was applied. In the SBR feeding phase, their variations rather than pH values were useful in predicting the ammonium behavior. This was formulated so that the reject water in the anoxic and aerobic phases was introduced semi-continuously. In the aerobic phase, the pH was suitable for determining the partial nitritation break-point. Its efficacy was verified in a pilot. A stable NRE of 90 ± 2.1 % was achieved even though the influent nitrogen fluctuated from 508.0 to 744.9 mg/L. In addition, as the SBR parameters (HRT, aerobic cycle, and exchange ratio) were optimized in real-time, the nitrogen removal rate further improved by 0.15 kg/m3/d.

Effect of AlN/GaN supercycle ratio on properties of AlxGa1−xN films using super-cycle plasma enhanced atomic layer deposition

In this study, aluminum gallium nitride (AlGaN) films are prepared by supercycle plasma enhanced vapor deposition (PEALD) with trimethylgallium, trimethylaluminum, and NH3 plasma. The ratio of aluminum nitride (AlN) to gallium nitride (GaN) PEALD cycle number is varied to investigated its effect on film properties. The experimental results show that the growth per cycle is lower than that of the mixing rule prediction, and the Ga content dramatically drops with increasing the AlN cycle ratio. It is implied that AlN surface partly hinders the growth of GaN during supercycle deposition. The Ga:Al elemental ratio is found to be 1:1 at the AlN cycle ratio of 20%, beyond which the film transforms from Ga-rich to Ga-poor and is accompanied with increased Al-Al metallic bonds. The film with the 20% AlN cycle ratio also exhibits the least aggregated surface morphology. The elemental depth profile investigated using secondary ion mass spectroscopy indicates an uniform distribution of Ga, Al and N. The bandgap of supercycle PEALD AlGaN films can be tuned when the AlN cycle ratio is less than 20%. Moreover, the AlGaN film with 20% AlN cycle ratio shows a photoluminescence peak centered at 277 nm, agreeing with the bandgap of the film.

Unknown bacterial species lead to soil CO2 emission reduction by promoting lactic fermentation in alpine meadow on the Qinghai-Tibetan Plateau

Highly variable soil microbial respiration among grasslands has been identified as a major cause of uncertainty in regional carbon (C) budget estimation in the Qinghai-Tibetan Plateau; microbial metabolism mechanisms might explain this variation, but remain elusive. Therefore, we investigated soil CO2 production in incubated soils and detected the associated functional genes at four sampling sites from two major alpine grasslands on the Qinghai-Tibetan Plateau. The results showed that the cumulative CO2 emissions from alpine meadow soils were 71 %–83 % lower than those from alpine steppe soils. Both the enriched genes abundance encoding fermentation and glycolysis (Embden-Meyerhof pathway (EMP)) and the diminished genes encoding tricarboxylic acid cycle (TCA) and phosphate pentose pathway (PPP) explained the CO2 emission reduction in the alpine meadow soils. The EMP: PPP and fermentation: TCA cycle ratios in alpine meadow soils were 1.45- and 1.50-fold higher than those in alpine steppe soils, respectively. Such shifts in metabolic pathways were primarily caused by the increasing dominance of an unknown species of Desulfobacteraceae with high glycolytic potential, carrying a higher abundance of ldh genes during fermentation. These unknown species were promoted by warmer temperatures and higher precipitation in the alpine meadows. Further studies on the unknown species would enhance our understanding and predictability of C cycling in alpine grasslands.

Echocardiographic characteristics and clinical outcomes in fetuses with pulmonary stenosis or pulmonary atresia with intact ventricular septum

To summarize echocardiographic characteristics of the anatomy and hemodynamic and clinical outcomes in fetuses with isolated pulmonary stenosis (PS) or pulmonary atresia with intact ventricular septum (PA/IVS). This was a single-center retrospective study of fetuses with isolated PS or PA/IVS. Echocardiographic variables and clinical outcomes after delivery were evaluated and compared. Between 2016 and 2021, 115 livebirths with isolated PS or PA/IVS were included. Proportion of fetuses with mild, moderate and critical PS and PA/IVS was 41.7%, 18.3%, 26.1% and 13.9%. Fetuses with more severe PS had worse anatomic and hemodynamic profiles. Specifically, the cardiothoracic ratio, pulmonary valve (PV) velocity, degree and velocity of tricuspid regurgitation increased as PS severity increased; and the pulmonary artery/aorta ratio, right ventricle/left ventricle long-axis (TV/MV) ratio, tricuspid valve/mitral valve annulus (TV/MV) ratio, and tricuspid valve inflow duration/cardiac cycle ratio decreased as PS severity increased (P <0.001 for all). PV velocity ≥2m/s predicted PV pressure ≥40mm Hg after delivery, with an AUC of 0.81; TV/MV ratio combined with RV/LV ratio predicted clinical outcomes, with an AUC of 0.88. Live births with more severe PS had higher mortality rate (mild 0 vs. moderate 0 vs. critical 11% vs. PA-IVS 36%) and lower rate of developing bi-ventricles (mild 100% vs. moderate 95% vs. critical 89% vs. PA-IVS 36%). Findings of this study help better understand the anatomy and hemodynamic and clinical outcomes in fetuses with isolated PS or PA/IVS, which could have implications for prenatal counseling and prediction of fetal outcome.

Optimizing energy storage performance of ALD YSZ thin film devices via yttrium concentration variations

In the last decade, research has focused on fabricating new materials to accelerate the development of energy storage devices. In this work, metal-electrolyte-metal (Au-YSZ-Ru) structures were fabricated on silicon substrates using atomic layer deposition, sputtering, and thermal evaporation techniques. The effect of the yttrium concentration in YSZ films on their chemical, structural, optical, and electrical properties were studied. XPS analysis showed yttrium concentrations of 14.6, 10.3, 6.8, and 5.3 at.% for films with ALD cycle ratios Zr:Y of 2:1, 4:1, 6:1, and 8:1. Deconvolution of the oxygen XPS signal demonstrate the yttrium to oxygen vacancies ratio. The band gap was calculated through UV–vis indicating an increase in values with yttrium concentration. In addition, the trend was confirmed by reflection electron energy loss spectroscopy (REELS). The structure was investigated by performing X-ray diffraction (XRD) and infrared attenuated total reflectance spectroscopy (IR-ATR) measurements. Both results indicate a better crystallization of the cubic phase for the samples with lower concentrations, as the intensity of (111) diffraction peaks and IR band increased for lower yttrium concentrations. Impedance spectroscopy revealed an activation energy of 1.69, 1.32, and 1.28 eV for the 10.3, 6.8, and 5.3 at.% film concentration, respectively. According to cyclic voltammetry and charge-discharge tests, a lower yttrium concentration, 5.3 at.%, promotes electrode REDOX reactions improving the energy-storage properties.

A nonlinear fatigue damage accumulation model under variable amplitude loading considering the loading sequence effect

Damage accumulation is nonlinear in the actual fatigue process, and the loading sequence is an important factor under variable amplitude loading. In this paper, a nonlinear fatigue damage accumulation model under variable amplitude loading considering the loading sequence effect is proposed. First, the cumulative rule of fatigue damage under variable amplitude loading is analyzed. It is suggested that the exponential function based on the load cycle ratio can be used to characterize the load sequence effect. Then, a nonlinear fatigue damage evolution equation of materials under constant amplitude load is proposed by taking the static toughness of the material as the damage parameter. Furthermore, the exponent of the load sequence influence parameter is determined as a function of the cycle life and elastic modulus. Then, a fatigue damage accumulation model under variable amplitude loading that considers the effect of the loading sequence is obtained based on the damage equivalence principle. Finally, the model is validated and compared through fatigue test data of five metal materials. It is found that the prediction accuracy of the proposed model is significantly higher than the other two models. In contrast, the difficulty of using the proposed model is lower than that of similar models.

Prok1 regulates the proliferation and apoptosis of ovarian granulosa cells in polycystic ovary syndrome via Pi3k/Akt/nf-κ B signaling route

Purpose: To investigate the regulatory influence of Prok1 on apoptotic and proliferative changes in PCOS, and the implication of Pi3k/Akt/nf-κ B signaling pathway in the process.Methods: Ovarian granulosa cells from a rat model of PCOS were assigned to control and si-Prok1 groups, after cell culture. Then, control lentivirus and Prok1 siRNA lentivirus (50 μL each) were added to the cells to the groups, respectively. Cell cycle ratio and apoptosis in the two groups were determined using flow cytometry, while Pi3k/Akt signal route-linked protein levels were assayed by immunoblot method.Results: The proportions of cells at G0/G1 and S phases of the cell cycle in si-Prok1 group were significantly lower than those in the control group, but G2/M phase cell population was significantly higher, relative to the control (p &lt; 0.01). There was significant down-regulation of protein expressions of cyclin A2 and cycline1 in si-Prok1 group, relative to control group, but p21 protein level was significantly higher in si-Prok1 group (p &lt; 0.05). There was a significantly higher apoptosis in si-Prok1 group. In the si-Prok1 cells, there were significant increases in protein levels of Bcl-2, cleaved caspase-9 and caspase-3, relative to control group, while protein expression levels of Bax, p-Pi3k and p-Akt in si-Prok1 group were significantly lower than the corresponding control values (p &lt; 0.05).Conclusion: si-Prok1 arrests cell cycle, induces apoptotic changes, and inhibits the proliferation of ovarian granulosa cells through a mechanism related to the regulation of Pi3k/Akt signaling pathway. Therefore, it might play a potential role in the treatment of polycystic ovary syndrome.

Fragmentation Evaluation of Some Selected Mudrock Indiced by Physical and Mineralogical Properties

Not many mudrock in Indonesia have been evaluated for slaking characteristics. Mudrock disintegrates rapidly when interacting with the atmosphere and hydrosphere. This research investigates the fragmentation of slaked claystone from the Kerek Formation. These formations are known for causing road, slope, and land-strengthening engineering problems along Jalan Semarang-Bawen, Middle Java, Indonesia. In this research, the method includes quantitative analysis of rock slaking level, which collides with the physical and mineralogical properties of the rocks. The slaking test with natural exposure for four cycles was carried out on as many as five samples. It is found the durability parameter value for all samples generally shows a slight difference. The durability index and Fragment Size Distribution Ratio in the 4-month cycle may be considered to evaluate the degree of fragmentation of material mudrock. RGL.0708.10 have an average DIR of 11.81%, and RGI.0908.1 is 2.18%. The value of FSDRatio for RGI.0908.2, RGL.0908.1, RGI.0908.1, and RGI.0708.3 is 1.00, whereas RGI.0708.10 is 0.9997. The indices in this research can be projected and considered to be used in another formation sample with engineering problems. The mineralogical composition of smectite minerals does not show a significant relationship to affect the fragmentation of mudrock with R2 .0.268 in month-4 for the DIR and 0.1322 for the FSDRatio . On the microscopic texture of the sample, there is the presence of calcite minerals, and a modest relationship exists between calcite content and its effect on the fragmentation of mudrock with R2 for DR and FSDRatio , respectively 0.6797 and 0.4732. In addition, physical properties such as natural water content highly influence mudrock’s durability with R2 for DIR and FSDRatio , respectively 0.8321 and 0.9023.

Characteristics and correlation between FFR and RFR of non-culprit lesions in acute myocardial infarction

Background: While resting-full cycle ratio (RFR) is strongly correlated with fractional flow reserve (FFR), it has been extensively examined in stable coronary artery disease. However, there is a lack of evaluation regarding non-culprit lesions in patients with acute myocardial infarction (AMI). Objectives: To investigate the clinical characteristics and to identify the correlation and discordance between FFR and RFR among AMI patients with non-culprit lesions. Methods: A retrospective cohort study was conducted in 44 AMI patients who underwent percutaneous coronary intervention (PCI) for culprit lesions and &gt; 90% stenosis non-culprit lesions. With non-culprit stenosis from 50 - 90%, 23 patients had simultaneous measurements of both FFR and RFR, and 17 patients underwent PCI based on FFR ≤ 0.8. Results: Approximately 79.5% of patients exhibited a presence of two or more risk factors associated with coronary artery disease. In 44 culprit lesions, 40.9% of cases located in the RCA branch, while in 46 nonculprit lesions, 61.4% of cases were found in the LAD branch. The average FFR among 44 patients was 0.82 ± 0.13. There was a significant improvement in FFR after PCI (0.89 ± 0.07) compared to pre-PCI (0.70 ± 0.11) in 17 patients with p &lt; 0.001. The mean RFR among the 23 patients was 0.84 ± 0.12. Among 12 patients with positive RFR, RFR after PCI (0.95 ± 0.04) was higher than pre-PCI (0.78 ± 0.13) with p = 0.002. Furthermore, pre-PCI RFR showed a strong positive correlation with FFR (r = 0.662, p = 0.001). The discordant rate between RFR and FFR was 26.8%. The discordant rate of FFR and RFR measurements was 26.1%. Additionally, the left anterior descending artery (LAD) was assumed as a predictor of discordance in the high FFR group (FFR &gt; 0.80) and low RFR group (RFR ≤ 0.89). Conclusion: The low discordance rate and strong correlation between FFR and RFR suggest their complementary roles in the assessment of intermediate non-culprit lesions in patients with AMI. Key words: fractional flow reserve, resting full-cycle ratio, non-culprit lesion, correlation, acute myocardial infarction.

Power density performances and multi-objective optimizations for an irreversible Otto cycle with five specific heat models of working fluid

Power density (Pd) performance for an irreversible Otto cycle is analyzed with constant specific heat (SH), linear and nonlinear variable SH, linear and nonlinear variable SH ratio of working fluid. Relationships among dimensionless Pd (P‾d), thermal efficiency (η) and compression ratio (γ) of cycle are obtained taking three loss items account into. Performances are compared when dimensionless power output (P‾) and P‾d are maximized with five SH models. Choosing γ as design parameter, and P‾, η, dimensionless ecological function and P‾d as performance parameters, multi-objective optimizations are carried out for five SH models by using NSGA-Ⅱ. Evaluating deviation indices (D s) under three decision-making methods, the optimal parameter combination with the smallest D is selected as the better one. Results show that SH model has no qualitative influence on relationship curve of P‾d−γ and P‾d−η, but it has quantitative influence. With linearly variable SH and constant SH, γP‾d reaches the maximum and minimum respectively. With linearly variable SH ratio and nonlinearly variable SH, ηP‾d reaches the maximum and minimum respectively. The D of LINMAP method with constant SH model is the smallest, which is 0.1236, and the D of Shannon entropy method with the nonlinear variable SH ratio model is the largest, which is 0.3664.

Stable isotope tracing internal recycling and evaporation losses in saline lakes on the Qinghai-Tibet Plateau

Direct measuring of internal lake recycling and evaporation losses remains challenging for lakes on the Qinghai-Tibet Plateau (QTP). Stable isotope techniques provide an effective approach for estimating water vapor cycling ratios and evaporation losses of lakes on the QTP. In this study, the stable isotope values of saline lakes on the QTP were modeled using the stable isotope values of the sampled lake water and their influencing factors. The water vapor recycling ratio and evaporation loss (E/I) of 135 saline lakes on the QTP were evaluated and their influencing factors were revealed. The results showed that stable isotopes in saline lakes on the QTP showed significant spatial variability. Their stable isotopes were affected by the source of water vapor, recharge patterns, and local evaporation conditions. It's worth noting that the average water vapor recycling ratio of saline lakes on the QTP was 20.16 %, one-fifth of the saline lakes had a water vapor recycling ratio beyond 30 %. Saline lakes lose 26 % of their water through evaporation. 26 % of the saline lakes experienced high evaporation losses of >40 % of the total inflow. We found that the main factors controlling the water vapor recycling ratio and evaporation loss in saline lakes on the QTP were precipitation and altitude, respectively. Interestingly, the control factors of water vapor recycling ratio and evaporation loss in saline lakes with elevation above 4500 m showed significant differences compared to saline lakes with elevation below 4500 m. Therefore, the strengthening of lake system monitoring can provide reliable data support for security assessment and effective management of water resources on the QTP.

Influences of particle size distribution and fines content on the excess pore water pressure generation of sand-silt mixtures under cyclic loading

The mechanical behaviors of binary mixtures are different from that of uniform soils. However, experimental studies on the dynamic responses of sand-silt mixtures considering the combined effects of fines content (FC) and host sand gradation are limited in the literature. In this paper, an experimental program was designed concerning five binary mixtures with three grain size ratios (Rd) and three sand uniformity coefficients (Cus) for investigating the effects of fines content and host sand gradation on both the liquefaction resistance and the excess pore water pressure (EPWP) generation of sand-silt mixtures. Results show that the effect of FC on the liquefaction resistance of sand-silt mixtures depends on relative density (Dr), grain size ratio, and sand uniformity coefficient. The liquefaction resistance of sand-silt mixture can be uniquely characterized by the equivalent relative density Dr* regardless of FC, Dr, and host sand gradation. Relationship between the EPWP ratio Ru and the cycle ratio N/NL for the sand-silt mixtures can be well expressed by the Seed model, which is significantly affected by cyclic stress ratio (CSR), FC, and Dr but insensitive to the change of host sand gradation. A trained artificial neural networks (ANN) model is conducted to predict the fitting parameter β of the Seed model with a maximum difference of 25% between the predicted and measured values. Moreover, there is an arctangent relationship between Ru and shear strain amplitude γa of each specimen, and the fitting parameter A for the relationship is sensitive to the particle size distribution and stress amplitude. A unique relationship between a density-corrected parameter A/Dr* and CSR is proposed regardless of FC and host sand gradation.

Understanding Patient Characteristics and Coronary Microvasculature: Early Insights from the Coronary Microvascular Disease Registry

Coronary angiography has limitations in accurately assessing the coronary microcirculation. A new comprehensive invasive hemodynamic assessment method utilizing coronary flow reserve (CFR) and the index of microvascular resistance (IMR) offers improved diagnostic capabilities. This study aimed to present early real-world experience with invasive hemodynamic assessment of the coronary microvasculature in symptomatic patients with nonobstructive coronary artery disease (CAD) from the Coronary Microvascular Disease Registry, which is a prospective, multi-center registry that standardized the evaluation of patients with angina and nonobstructive CAD who underwent invasive hemodynamic assessment of the coronary microvasculature using the Coroventis CoroFlow Cardiovascular System. All patients underwent comprehensive invasive hemodynamic assessment. Analysis was performed on the first 154 patients enrolled in the Coronary Microvascular Disease Registry; their mean age was 62.4years and 65.6% were female. A notable proportion of patients (31.8%) presented with a Canadian Cardiovascular Society Angina Score of 3 or 4. Coronary microvascular dysfunction was diagnosed in 39 of 154 patients (25.3%), with mean fractional flow reserve of 0.89±0.43, mean resting full cycle ratio of 0.93±0.08, mean CFR of 1.8±0.9, and mean IMR of 36.26±19.23. No in-hospital adverse events were reported in the patients. This study demonstrates the potential of invasive hemodynamic assessment using CFR and IMR to accurately evaluate the coronary microvasculature in patients with nonobstructive CAD. These findings have important implications for improving the diagnosis and management of coronary microvascular dysfunction, leading to more targeted and effective therapies for patients with microvascular angina.

Analysis of the hydrodynamic damping of a hydrofoil with leading edge cavitation using the modal work approach

The objective of this investigation is to evaluate the applicability and accuracy of the modal work approach in predicting the hydrodynamic damping of a hydrofoil with leading edge cavitation. Simulations are carried out at a flow velocity of 6.64 m/s, an attack angle of 10°, and cavitation numbers between 1.04 and 2.02. The grid scale, time step, and mode shape amplitude are carefully verified. Results for the cavitation shedding frequencies and hydrofoil natural frequencies show good agreement between experiment and simulation, with relative errors within 8.76% and 7.12%, respectively. The unsteady characteristics of leading edge cavitation have a significant influence on the modal parameters, such as the variation in natural frequency can reach 32.57% in a cavitation cycle and the corresponding mode shape is also changed. Therefore, a new strategy including unsteady mode analysis and energy dissipation signal filtering is proposed to simulate the hydrodynamic damping ratio with leading edge cavitation. Then, the time-averaged hydrodynamic damping ratio in a cavitation cycle is obtained, with relative errors between 15.11% and 35.57% by comparing them with the experimental results. This study realizes the application of the modal work approach in leading edge cavitation conditions.

Improved electrical contact property of Si-doped GaN thin films deposited by PEALD with various growth cycle ratio of SiNx and GaN

Gallium Nitride (GaN) is becoming increasingly attractive due to its advantages in efficiency, switching speed, and high temperature operation. Although the performance of GaN in light-emitting devices and power electronics has been significantly improved, the need to reduce the power loss of GaN-based devices still exists. In this paper, Si derived from the SiNx sub-cycle in plasma-enhanced atomic layer deposition (PEALD) was used as a dopant to improve the ohmic contact resistance of GaN. The doping concentration of Si ranging from 0% to 33 at% were obtained by varying the SiNx sub-cycle ratio from 0% to 50%. A 13.56 at% Si-doped GaN film with moderate SiN bonding deposited at a SiNx sub-cycle ratio of 20% exhibits the highest carrier concentration of 1.29 × 1018 cm−3 and the lowest resistivity of 0.78 Ω·cm. The transmission line model (TLM) measurements show that the as-deposited Si-doped GaN has a specific contact resistance of 4.77 × 101 Ω·cm2, which decreases to 8.15 × 10−4 Ω·cm2 after annealing at 500 °C.

Electronic Pair-Action Pulsator of the Milking Machine

The dairy cattle breeding market is analyzed. The dairy industry in the country remains one of the most problematic aspects of the economy, despite unprecedented measures of state support. (Research purpose) The research purpose is increasing the efficiency of machine milking of cows by developing and justifying the design and operating parameters of a milking machine with an electromagnetic pulsator, which allows reducing the negative impact of irritating factors during milking on animal health, ensuring fast and comfortable milking, increasing milk yield, eliminating the possibility of vacuum fluctuations in the suction chambers and working with any milking unit or apparatus. (Materials and methods) The analysis of the dairy products market and the mechanisms responsible for the formation of a pulsating vacuum during milking of lactating animals was carried out. (Results and discussion) We have developed a promising electromagnetic pulsator for machine milking of cows. It was shown that it differs from other models by the presence of a hole in the upper part of the body and a disc-shaped lower valve, which reduces air consumption and increases the reliability of the design. We solved the problem of improving the operation of milking machines and bringing machine milking closer to the physiological features of the milk-giving process. It was found that the pulsator reduces mechanical loads on the nipple tissue in lactating animals and eliminates the reverse flow of milk in the nipple chamber, which prevents the appearance of mastitis diseases. (Conclusions) Analytical studies of analogs and comparative analysis of the proposed design of the electromagnetic pulsator were carried out. It was determined that the use of a pulsator will provide a reduction in the pulse (shock) effect of the nipple rubber on the nipple tissue by increasing the transition phase from the sucking stroke to the compression stroke by 60-65 percent in comparison with series-produced pneumatic pulsators. It was revealed that with the help of the developed device, it is possible to adjust the ratio of cycles depending on the intensity of dairy production of cattle to reduce the harmful effect of milking on the health of the animal.

High figure-of-merit in Al-doped ZnO thin films grown by ALD through the Al content adjustment

The development of transparent conductive materials is of great interest for a wide variety of semiconducting devices in the fields of optoelectronics and photovoltaics. Here, we optimize the growth and properties of aluminum-doped ZnO (AZO) thin films as an eco-friendly transparent electrode by using atomic layer deposition (ALD) with diethylzinc (DEZn), water vapor and trimethylaluminium (TMA) as zinc, oxygen, and aluminum chemical precursors, respectively. The cycle ratio of DEZn to TMA using ALD is adjusted to control the Al atomic concentration over a broad range of 0.3 - 6.7% while optimizing the structural, optical, and electrical properties of AZO thin films. By incorporating a sufficient amount of Al dopants around 1.1%, we obtain a high quality AZO thin film exhibiting a low electrical resistivity of 6.3 × 10−4 Ω·cm. This AZO thin film grown on quartz substrate also demonstrates an average optical transmittance in the visible range above 85% as well as a high figure-of-merit of 6.4 × 10−3 Ω−1, while maintaining its highly c-axis oriented structure. The present optical and electrical properties result in the fabrication of AZO thin films by ALD with a high figure-of-merit that is highly suitable for many semiconducting devices.

Yttrium Doping Effects on Ferroelectricity and Electric Properties of As-Deposited Hf1-xZrxO2 Thin Films via Atomic Layer Deposition.

Hf1-xZrxO2 (HZO) thin films are versatile materials suitable for advanced ferroelectric semiconductor devices. Previous studies have shown that the ferroelectricity of HZO thin films can be stabilized by doping them with group III elements at low concentrations. While doping with Y improves the ferroelectric properties, there has been limited research on Y-HZO thin films fabricated using atomic layer deposition (ALD). In this study, we investigated the effects of Y-doping cycles on the ferroelectric and electrical properties of as-deposited Y-HZO thin films with varying compositions fabricated through ALD. The Y-HZO thin films were stably crystallized without the need for post-thermal treatment and exhibited transition behavior depending on the Y-doping cycle and initial composition ratio of the HZO thin films. These Y-HZO thin films offer several advantages, including enhanced dielectric constant, leakage current density, and improved endurance. Moreover, the optimized Y-doping cycle induced a phase transformation that resulted in Y-HZO thin films with improved ferroelectric properties, exhibiting stable behavior without fatigue for up to 1010 cycles. These as-deposited Y-HZO thin films show promise for applications in semiconductor devices that require high ferroelectric properties, excellent electrical properties, and reliable performance with a low thermal budget.