Angle Characteristics Research Articles

Structure Design on Thermoplastic Composites Considering Forming Effects.

Carbon fiber reinforced polypropylene (CF/PP) thermoplastics integrate the superior formability of fabrics with the recoverable characteristics of polypropylene, making them a pivotal solution for achieving lightweight designs in new energy vehicles. However, the prevailing methodologies for designing the structural performance of CF/PP vehicular components often omit the constraints imposed by the manufacturing process, thereby compromising product quality and reliability. This research presents a novel approach for developing a stamping-bending coupled finite element model (FEM) utilizing ABAQUS/Explicit. Initially, the hot stamping simulation is implemented, followed by the transmission of stamping information, including fiber yarn orientation and fiber yarn angle, to the follow-up step for updating the material properties of the cured specimen. Then, the structural performance analysis is conducted, accounting for the stamping effects. Furthermore, the parametric study reveals that the shape and length of the blank holding ring exerted minimal influence on the maximum fiber angle characteristic. However, it is noted that the energy absorption and crushing force efficiency metrics of the CF/PP specimens can be enhanced by increasing the length of the blank holding ring. Finally, a discrete optimization design is implemented to enhance the bending performance of the CF/PP specimen, accounting for the constraint of the maximum shear angle resulting from the stamping process. The optimized design resulted in a mass reduction of 14.3% and an improvement in specific energy absorption (SEA) by 17.5% compared to the baseline sample.

Temperature tunable ultra-wideband absorber based on ionic liquid

Abstract In this paper, a temperature tunable ultra-wideband absorber based on ionic liquid is proposed for the microwave frequency band. The absorber consists of a band-resistive frequency selective surface (FSS), a 3D resin cavity vessel, and an ionic liquid ([EMIm][N(CN)2]) layer. Numerical simulation analysis shows that the absorptivity is more than 90% and a relative bandwidth is 113.04% in the range of 7.5-27 GHz. Meanwhile, the absorber absorptivity has different tuning effects in different frequency bands with the change of temperature. Along with the temperature going up, the absorptivity decreases in the low-frequency band of 6.5-14 GHz, the absorptivity increases in the high-frequency band of 28 GHz to 40 GHz. It is worth mentioning that the proposed ionic liquid-based absorber has the characteristics of wide incidence angle and polarization insensitivity. Finally, the temperature tunable absorber model based on ionic liquid is fabricated by 3D printing technology. The experimental results are consistent with the simulation results, demonstrating that the absorber is practically feasible. In summary, the absorber achieves a wide frequency tuning range, which gives it great potential application prospects in fields such as frequency-selective thermal radiators.

Improving Viewing Angle Characteristics of Top-Emission Micro-Cavity OLEDs with Randomly Distributed Micro Lens Arrays

Improving Viewing Angle Characteristics of Top-Emission Micro-Cavity OLEDs with Randomly Distributed Micro Lens Arrays

Acoustic measurement around the pinna in the VHF region using a dummy head

We investigated the azimuth and vertical angle characteristics of head related transfer function (HRTF) at very high frequency region using head and torso simulator (HATS). The VHF sounds contain potential hazards for young people who can hear such sounds. Therefore, the relationship between hearing thresholds in very-high frequency (VHF) region and intensity of VHF sounds are very important for considering human impact. The former means sound pressure level (SPL) at eardrum, and the latter is SPL at center of two ears without a head. The difference between two SPLs means head-related transform function (HRTF). In this paper, we reported the HRTFs measured in VHF region for the azimuth and vertical angles by using a HATS. The complicated contour maps of HRTFs for angle and frequency show that the SPLs at eardrum in VHF region depend on among material, size and figure of a pinna.

Numerical Investigation of Flow Characteristics in Internally Flowing Pipes with Varying Roughness and Helical Angles of Vortex Generators

In this study, the turbulent behavior inside a pipe containing an aluminum helical vortex generator plate was investigated using computational fluid dynamics (CFD) methods, considering different plate roughness and helical angle values. Accordingly, numerical analyses of velocity and pressure distributions for a liquid flow with a constant inlet velocity of 0.5 m/s and four different helical angles were performed and compared in a computer software. To observe the effects of the roughness values of the metal plate on flow behavior, analyses were conducted for three different roughness values for each helical angle and the results were compared and interpreted. As a result of the study, the combination of a roughness value of 0.04 and a helical angle of 0° led to the highest pressure and velocity values, while the same roughness value combined with a 270° helical angle resulted in the lowest pressure and velocity values. Detailed analysis showed that helical angles (90° and 180°) presented moderate pressure and velocity values, indicating a non-linear relationship between helical angle and flow characteristics. The results demonstrate that optimizing the helical angle and roughness is crucial for enhancing the efficiency of vortex generators. This way, a design will be developed to prevent performance degradation in industrial applications that require flow efficiency and pressure management.

Effects of Spray Adjuvants on Droplet Deposition Characteristics in Litchi Trees under UAV Spraying Operations

In the last decade, unmanned aerial vehicles (UAVs) for plant protection have rapidly developed worldwide as a new method for pesticide application, especially in China and other Asian countries. To improve the deposition quality in UAV applications, adding appropriate types of spray adjuvants into pesticide solutions is one of the most effective ways to facilitate droplet deposition and control efficacy. At present, research on spray adjuvants for UAVs are mainly based on droplet drift and laboratory tests. Few studies have been conducted on the physicochemical properties of spray adjuvants and the effects of droplet deposition characteristics. To explore the properties of four different kinds of spray adjuvants (Mai Fei, Bei Datong, G-2801, and Agrospred 910) and the deposition characteristics of spray adjuvants on litchi leaves, an automatic surface tension meter, a contact angle measuring device, an ultraviolet visible spectrophotometer, and a DJI AGRAS T30 plant protection UAV was used to measure the surface tension, contact angle, and droplet deposition characteristics on litchi under UAV spraying operations. The results showed that the addition of spray adjuvants could significantly reduce the surface tension of the solution. The surface tension value of the solution after adding the spray additives was reduced by 53.1–68.9% compared with the control solution. Among them, the Agrospred 910 spray adjuvant had the best effect on reducing the surface tension of the solution. The contact angle of the control solution on the litchi leaves varied from 80.15° to 72.76°. With the increase in time, the contact angle of the spray adjuvant solution gradually decreased, the Agrospred 910 spray adjuvant had the best effect, and the contact angle decreased from 40.44° to 20.23° after the droplets fell on the litchi leaves for 60 s. The adjuvant solutions increased the droplet size, but the uniformity of the droplet size decreased. The Dv0.5 of different spray solutions ranged from 97.3 to 117.8 μm, which belonged to the fine or very fine droplets, and the Dv0.5 of adjuvants solutions were significantly greater than that of the control solution. The RSs of adjuvant solutions were very similar and ranged from 0.92 to 0.96, all of which were significantly greater than the result of the control solution (0.57). Compared with the deposition of the control solution, the Mai Fei, Bei Datong, and G-2801 solutions clearly increased spray deposition, with total depositions of 0.776, 0.705, and 0.721 μL/cm2, which are all greater than the total deposition of the control solution of 0.645 μL/cm2. The addition of tank-mixed adjuvants could effectively increase the uniformity of the spray deposition, and all the average CVs of adjuvant solutions were lower than 96.86%. On the whole, Mai Fei performed best in increasing the spray deposition and promoting penetration, followed by Bei Datong and G-2801. Meanwhile, the test can also provide a reference for improving the utilization rate of UAV pesticide applications.

Görtler Vortices in the Shock Wave/Boundary-Layer Interaction Induced by Curved Swept Compression Ramp

This study builds on previous research into the basic flow structure of a separated curved swept compression ramp shock wave/turbulence boundary layer interaction (CSCR-SWBLI) at the leading edge of an inward-turning inlet. We employ the ice-cluster-based planar laser scattering (IC-PLS) technique, which integrates multiple observation directions and positions, to experimentally investigate a physical model with typical parameter states at a freestream Mach number of 2.85. This study captures the fine structure of some sections of the flow field and identifies the presence of Görtler vortices (GVs) in the CSCR-SWBLI. It is observed that due to the characteristics of variable sweep angle, variable intensity interaction, and centrifugal force, GVs exhibit strong three-dimensional characteristics in the curved section. Additionally, their position is not fixed in the spanwise direction, demonstrating strong intermittence. As the vortices develop downstream, their size gradually increases while the number decreases, always corresponding to the local boundary layer thickness. When considering the effects of coupling of bilateral walls, it is noted that the main difference between double-sided coupling and single-sided uncoupling conditions is the presence of a large-scale vortex in the central plane and an odd number of GVs in the double-sided model. Finally, the existence of GVs in CSCR-SWBLI is verified through the classical determine criteria Görtler number (GT) and Floryan number (F) decision basis.

Numerical investigation of tip bifurcation on aerodynamic characteristics and flow field structure in a compressor cascade

In this study, the tip bifurcation of the compressor cascade is proposed, referring to the biological characteristics of bird wing bifurcation. The influence of tip bifurcation with different structural parameters on the aerodynamic performance and flow field structure of compressor cascade at different incidence angles is studied by numerical simulation. The research shows that the tip bifurcation can make the starting position of the corner separation move backward, inhibit the separation along the pitch and blade height direction, and reduce the flow loss of the cascade. The separation control effect of the corner region first increases and then decreases as the bifurcation height increases, and gradually diminishes as the arrangement position approaches the trailing edge. When the tip bifurcation is set at the starting position of the corner separation and its height is equal to 4 %H, the flow improvement effect in the passage is the most obvious, and the cascade flow loss is reduced by 14.4 %. At the same time, the tip bifurcation cascade has effective positive incidence angle characteristics, but when the incidence angle is less than the minimum loss incidence angle, the tip bifurcation increases the cascade loss.

Identification of generator coherency in power systems with wind farm

In the context of the "dual carbon" goal, the penetration rate of new energy represented by wind power is gradually increasing. The large-scale grid connection of wind power makes the power system more complex and uncertain. The output of wind farms changes the system flow, indirectly affecting the power angle characteristics of synchronous generators, and thereby changing the coherence between generators. Affects synchronous generator homology identification. This paper proposes a generator homology identification method for power systems containing wind farms, in response to the problem that the existing methods for identifying unit homology have not taken into account the adverse effects of wind farms on identification results. Translate the influence of wind farms on the homology of synchronous generators into the contraction admittance matrix as a static electrical distance indicator; Select dynamic data reflecting the homology of synchronous generators after disturbance, and form four dynamic indicators to measure the power angle increment curve between each generator: Euclidean distance, Chebyshev distance, grey correlation, and correlation coefficient; By using the combination weighting method to determine the weights of each indicator, a comprehensive similarity matrix is formed, and the optimal clustering results are determined using fuzzy system clustering and F-statistical values. Finally, the effectiveness of the proposed method was verified using EPRI-9 node system, EPRI-36 node system, and IEEE68 node system as examples.© 2017 Elsevier Inc. All rights reserved.

Flow in fracture Intersections: Deflection flow assumption reexamined

Deflection flow, which represents the process of flow redistribution at fracture intersections, is essential for accurately predicting fluid infiltration and contaminant transport in fracture networks. However, previous studies focused on the outcome of flow redistribution but neglected the process, leading to poor knowledge of deflection flow at intersections. In this study, numerical investigations of the deflection flow in cross fractures were carried out based on Navier-Stokes equations and the results were compared with previous experiments. Geometrical characteristics such as angle(φ), aperture ratio(k), and hydraulic characteristics like inlet flow ratio(n) were considered to explore the mechanism of deflection flow. The deflection flow intensity(Xφ) was introduced to characterize the magnitude and direction of the deflection flow. The results showed that the deflection flow is caused by unequal local head loss. The effect of φ on Xφ is limited by n and k. Increasing n or k enhances the deflection flow but the directions of the induced deflection flow are reversed. The obtained relationship was further supported by theoretical results derived from the cubic law. Subsequently, sensitivity analysis of impact factors to the deflection flow was carried out by the Morris method, the sensitivity in descending order was k, n, φ. Finally, based on the analysis of Xφ, the conditions to limit the occurrence of deflection flow was obtained as a linear positive correlation between the critical inlet flow ratio(nc) and aperture ratio(k). The results from this study may provide insights and physical constraints on construction of flow models based on discrete fracture networks.

Ship Autonomous Berthing Strategy Based on Improved Linear-Quadratic Regulator

There has been significant interest in the research field of ship automatic navigation, particularly in the area of autonomous berthing. To address the key challenges of path planning and control during ship berthing, we propose an enhanced Linear−Quadratic Regulator (LQR) control approach, reinforced by the Covariance Matrix Adaptation Evolution Strategy (CMA−ES), along with an adaptive berthing strategy decision model. This integrated framework encompasses ship motion control, path planning, and berthing strategy selection to facilitate adaptive and autonomous ship berthing. Initially, a dynamic mathematical model of ship motion is established, taking into account wind and current interference effects. Subsequently, an adaptive environment−aware berthing strategy model is introduced to enable automatic selection of berthing strategies based on spatial relationships between environmental factors and the berth. By utilizing the refined LQR method, autonomous motion control for ship berthing is achieved. To validate the effectiveness of our controller, comprehensive simulation analyses are conducted under varying operating conditions to encompass crucial factors such as large drift angle characteristics of ships, shallow water effects, and bank effects across seven diverse working conditions. The simulation results underscore the robustness of our proposed method in responding to environmental interference while demonstrating its capability to select appropriate berthing strategies based on varying operational scenarios.

Transport properties through alternating borophene and graphene superlattices

The electronic transport properties of two junctions (BGB, GBG) made of borophene (B) and graphene (G) are investigated. Using the transfer matrix method with Chebyshev polynomials, we have studied single and multiple barriers in a superlattice configuration. We showed that a single barrier exhibits remarkable tilted transport properties, with perfect transmission observed for both junctions under normal incidence. We found that robust superlattice transmission is maintained for multiple barriers, particularly in the BGB junction. It turns out that by varying the incident energy, many gaps appear in the transmission probability. The number, width, and position of these transmission gaps can be manipulated by adjusting the number of cells, incident angle, and barrier characteristics. For diffuse transport, we observed considerable variations in transmission probability, conductance and the Fano factor, highlighting the sensitivity of these junctions to the physical parameters. We showed different behaviors between BGB and GBG junctions, particularly with respect to the response of conductance and Fano factor when barrier height varies. For ballistic transport, we have seen that the minimum scaled conductance is related to the maximum Fano factor, demonstrating their control under specific conditions of the physical parameters. Analysis of the length ratio (geometric factor) revealed some remarkable patterns, where scaled conductance and the Fano factor converged to certain values as the ratio approached infinity.

Anatomical Variation of Sternal Angle and Body: a Cross sectional study

Background: The sternum is one of the important skeletal components ofthoracic case that frequently has congenital defects, and researchers routinely use variances to ascertain an individual's age and sex. Additionally, it helps the physician with biopsy procedures as well as therapy. The objective of this study was to evaluate the morphological characteristics of sternal body and sternal angle in both sexes. Method: This cross-sectional stuywas carried out at the Department of Anatomy, Sylhet MAG Osmani Medical College. For this purpose, 100 dried ossified sternums of unknown sex had been collected. The sample was collected in compliance with the inclusion and exclusion criteria. Discriminant function analysis was used to determine the sex of each sternum (DFA). Study variables were the maximum length of sternal body, maximum breadth of sternal body, thickness of the sternal body and sternal angle. Variables were measured using a vernier caliper and documented in a pre-designed data sheet. Result: The mean length of the body of sternum was 93.84±23.31 mm in male and 82.84±14.8 mm in female. The mean width of the body of the sternum was 35.3±10.83 mm in male and 29.22±9.65 mm in female. The thickness of the body of the sternum is 19.86±9.91 mm in males and 16.12±7.39 mm in females. Analysis revealed that length of body sternum, width of body of sternum and thickness of body of sternum were higher in male than female which was statistically significant (p<0.05).The mean angle of sternum was 148.29±8.240 degrees in males and 149.32±9.690degrees in females, respectively. The difference was statistically not significant (p<0.05). Conclusion: In females, the maximum sternal length, maximum sternal breadth, and maximum sternal thickness were all significantly lower.

Anterior Chamber Angle and Intraocular Pressure Control After Phacoemulsification in Primary Angle Closure With Different Mechanisms.

Different mechanisms of angle closure represented distinct aspects of intraocular pressure (IOP) control after phacoemulsification. Classification of angle closure mechanisms is necessary for postoperative IOP management and glaucoma progression in primary angle closure eyes. To investigate the relationship between the anterior chamber angle (ACA) characteristics, measured by swept-source anterior segment optical coherence tomography (SS AS-OCT), and intraocular pressure (IOP) control after phacoemulsification in eyes with primary angle closure disease (PACD) with different angle closure mechanisms. PACD eyes were classified into 3 groups according to angle closure mechanisms using preoperative SS AS-OCT images; pupillary block (PB), plateau iris configuration (PIC), exaggerated lens vault (ELV). This retrospective, clinical cohort study included eighty-five eyes of 85 PACD patients: 34 with PB, 23 with PIC, and 28 with ELV. ACA parameters were measured preoperatively and 1 month postoperatively using SS AS-OCT. IOP measurements were performed preoperatively and during 6 months postoperatively. Postoperative IOP reduction and fluctuation were calculated, and their correlations with SS AS-OCT parameters were analyzed. PIC group showed the lowest postoperative IOP reduction compared with the other groups ( P =0.023). Preoperative ACA measurements were significantly associated with postoperative IOP reduction in ELV and PB groups, while postoperative measurements were in PIC group. Preoperative and postoperative change of iridotrabecular contact (ITC) index and area were correlated with postoperative IOP reduction in PB and ELV groups but not in PIC group. Postoperative ITC index ( P =0.031) and area ( P =0.003) showed significant correlations with postoperative IOP fluctuation only in PIC group. SS AS-OCT parameters including ITC index and area showed different associations with postoperative IOP control, which should be considered in determination of lens extraction and treatment of PACD eyes.

The Effect of Diets Containing Different Amounts of Chasteberry Seed (Vitex Agnus Castus) On Performance, Carcass, Meat Quality and Stress Parameters of Japanese Quails

Aim of study: To investigate the effects of diets containing different amounts of chasteberry seeds (Vitex agnus- castus L.) on the growing performance, slaughter characteristics, breast meat quality characteristics and stress parameters of Japanese quails (Coturnix coturnix japonica). Area of study: Çakmar, Aydın, Türkiye. Material and methods: A total of 240 one-day-old mixed-sex Japanese quail chicks (9.38 ± 0.02 g) were divided into three treatments with four replicates of 20 birds each in a completely randomized design. The groups were fed a control diet without chasteberry seeds (CS0), a diet containing 25 g/kg chasteberry seeds (CS25), and a diet containing 50 g/kg chasteberry seeds (CS50). The experiment lasted 35 days. Main results: Body weight, body weight gain, and feed intake of the CS50 group were found to be lower than the other groups on days 0-35 (p<0.05). No statistically significant difference was found in carcass and internal organ weights (p>0.05). Except for breast meat water holding capacity, lightness, redness, and hue angle characteristics in females, the effects of diets containing different chasteberry seeds on the meat quality characteristics of male and female quails were not significant (p>0.05). CS25 and CS50 diets caused a statistically significant increase (p<0.05) in glutathione, catalase, and superoxide dismutase values and a statistically significant decrease (p<0.05) in malondialdehyde values in male quail breast meat. Economically, although the lowest feed cost was obtained in the CS50 group, there was no difference in net profit between the groups. Research highlights: The addition of 25 g/kg chasteberry seeds in quail diets can be used easily without any negative effects. However, further studies are needed to determine the effects of different doses of chasteberry seeds on performance and meat quality.

Evaporation Dynamics of Deionized Water Droplets on Rough Substrates: The Coupling of Stick-Jump Motion And Evaporation

Abstract Substrate roughness can greatly affect the evaporation of sessile droplets, thus determining the efficiency of applications, such as ink-jet printing and coating. Here, we conduct experiments on the evaporation of deionized water droplets on glass substrates with roughness in the range 0.1 - 0.2 µm to investigate its effect on the dynamics of the contact angle and radius, as well the heat and mass transfer during evaporation. We discover a “stick-jump” phenomenon as part of a five-stage process that is determined by the evolution characteristics of the contact angle and radius, and includes the volume expansion, first stick, second stick, jump and final stages. Moreover, we find that the evaporation mode of the droplets is not affected by the increase of substrate roughness, whereas the heat and mass transfer processes intensify with the increase of substrate roughness in the presence of non-uniform evaporation effects. Also, the pinning-depinning mechanism of the “stick-jump” phenomenon during evaporation is carefully analyzed in terms of the Gibbs free energy, thus establishing a relation among Gibbs and excess Gibbs free energies and substrate roughness, which predicts the evaporation dynamics of the droplet. We anticipate that this study unravels key aspects of the droplet evaporation-mechanisms on rough substates toward optimizing and advancing relevant technology applications.

Pickering emulsion stabilized by cellulose nanofibril from pineapple leaves for biofoam manufacture

Cellulose nano fibril (CNF) can be selected as an agent of pickering emulsion in biofoam manufacture. This study thoroughly investigates the pickering emulsion method for producing biofoam, the characterization of CNF from pineapple leaves, the production of biofoam with various concentration of CNF and surfactant, and the effect of these parameters on the properties of wet foam and dry foam. CNF was created by mechanical grinding then the stability and morphology were evaluated. The pickering emulsion mechanism in biofoam manufacture was investigated using foamability and foam stability with various CNF and surfactant concentration. As the results, CNF concentrations will create varying zeta potential values. The morphology of CNF shows that it has a structure-like entangled network. The stability test demonstrates that adding CNF improves the stability and foamability of biofoam by the pickering effect. Biofoam without CNF has an unstable structure and is easily collapse when dried in an oven. The concentration of CNF and the amount of surfactant utilized altered the qualities of both wet and dry foam. The lower concentration of CNF and the addition of surfactant could increases foamability, high porosity, water absorption, and biodegradability; as well as low density, contact angle and bending characteristics. In biofoam that consists of 2 % CNF, the stability of wet foam increases as the amount of surfactant added, resulting in a biofoam with low tensile strength.

Anterior chamber and angle characteristics in Chinese children (6–11 years old) with different refractive status using swept-source optical coherence tomography

BackgroundThe anatomic structure of the anterior chamber (AC) helps to explain differences in refractive status in school-aged children and is closely associated with primary angle closure (PAC). The aim of this study was to quantify and analyze the anterior chamber and angle (ACA) characteristics in Chinese children with different refractive status by swept-source optical coherence tomography (SS-OCT).MethodsIn a cross-sectional observational study, 383 children from two primary schools in Shandong Province, China, underwent a complete ophthalmic examination. First, the anterior chamber depth (ACD), anterior chamber width (ACW), angle-opening distance (AOD), and trabecular-iris space area (TISA) were evaluated automatically using a CASIA2 imaging device. AOD and TISA were measured at 500, 750 μm nasal (N1 and N2, respectively), and temporal (T1 and T2, respectively) to the scleral spur (SS). Cycloplegic refraction and axial length (AL) were then measured. According to spherical equivalent refraction (SER), the children were assigned to hyperopic (SER > 0.50D), emmetropic (-0.50D < SER ≤ 0.50D), and myopic groups (SER ≤ -0.50D).ResultsOut of the 383 children, 349 healthy children (160 girls) with a mean age of 8.23 ± 1.06 years (range: 6–11 years) were included. The mean SER and AL were − 0.10 ± 1.57D and 23.44 ± 0.95 mm, respectively. The mean ACD and ACW were 3.17 ± 0.24 mm and 11.69 ± 0.43 mm. The mean AOD were 0.72 ± 0.25, 0.63 ± 0.22 mm at N1, T1, and 0.98 ± 0.30, 0.84 ± 0.27 mm at N2, T2. The mean TISA were 0.24 ± 0.09, 0.22 ± 0.09mm2 at N1, T1, and 0.46 ± 0.16, 0.40 ± 0.14mm2 at N2, T2. The myopic group had the deepest AC and the widest angle. Compared with boys, girls had shorter AL, shallower ACD, narrower ACW, and ACA (all p < 0.05). By Pearson’s correlation analysis, SER was negatively associated with ACD, AOD, and TISA. AL was positively associated with ACD, ACW, AOD, and TISA. In the multiple regression analysis, AOD and TISA were associated with deeper ACD, narrower ACW, and longer AL.ConclusionIn primary school students, the myopic eyes have deeper AC and wider angle. ACD, ACW, AOD, and TISA all increase with axial elongation. ACA is highly correlated with deeper ACD.

Etching Rate Analysis Model Based on Quartz Bond Angle Characteristics

This paper proposes a method for classifying crystal planes based on the bond angle characteristics of quartz unit cells and constructs an etch rate model for quartz crystal planes at both macro and micro scales. By omitting oxygen atoms from the quartz cell structure, a method based on bond angle characteristics was established to partition the atomic arrangement of the crystal surface. This approach was used to analyze the etching processes of typical quartz crystal planes (R, r, m, and (0001)), approximating the etching process of crystals as a cyclic removal of certain bond angle characteristics on the crystal planes. This led to the development of an etch rate model based on micro-geometric parameters of crystal planes. Additionally, using the proposed bond angle classification method, the common characteristics of atomic configurations on the crystal plane surfaces within the X_cut type were extracted and classified into seven regions, further expanding and applying the etch rate model. The computational results of this model showed good agreement with experimental data, indicating the rationality and feasibility of the proposed method. These also provide a theoretical basis for understanding the microstructural changes during quartz-based MEMS etching processes.

An Interactive Pedagogical Tool for Simulation of Controlled Rectifiers

Active learning approaches, incorporating student engagement through experimentation and problem solving, effectively foster higher-level thinking abilities and enhance academic performance. Interactive tools like simulators align with these methodologies, but commercially available simulators have limitations; particularly, their high cost and lack of customization features pose significant challenges for many educational institutions. This article presents CORES, a web-based educational application designed to simulate controlled rectifier circuits. CORES eliminates the need for intricate circuit assembly and software installation by providing pre-built circuits so that users can concentrate on analyzing circuit behavior by manipulating the thyristor firing angle and load characteristics, while the application generates output voltage and current waveforms under steady-state conditions, minimizing computation time. CORES has proven to be a valuable pedagogical tool, surpassing commercial simulators in terms of accessibility, ease of use, and enriched learning experiences for power electronics students and educators.