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Indoor positioning is crucial for everyday life, and received signal strength-based fingerprint localization is the most effective method. However, updating the fingerprint database is laborious, as changes in indoor layout would render the initial radio map outdated. To address this issue, we propose a precise radio map construction method by clustering and interpolating virtual fingerprints. The affinity propagation clustering algorithm and Voronoi diagram are used to group fingerprints with similar characteristics, mitigating the negative effects of multipath fading and shadowing caused by changes in the indoor layout. After generating synthetic reference points using the gradient extrapolation method to expand the convex hull, natural neighbor interpolation can construct accurate virtual fingerprints. Experimental results show that our proposed method outperformed both inverse distance weighting and Kriging interpolation by up to 33% in localization accuracy across diverse environments. This approach enables efficient radio map generation with comparable localization accuracy to the original radio map without extensive site surveys. [ABSTRACT FROM AUTHOR]

We used real plant data obtained from a water treatment plant in Peninsular Malaysia to develop a model to predict fluoride concentration in treated water. We validated the model with real plant data and demonstrated that the model yields good prediction, with mean absolute percentage error close to 10% or less. The validated model was then used to design an internal model control (IMC) tuned feedback controller, combined with a time‐varying feedforward control approach by exploiting the predictable and repetitive pattern of the inlet water flow rate. Simulation studies using random and real disturbance data show that the proposed control has successfully prevented over fluoridation in treated water. The validated model, due to its simplicity, is suitable for future online implementation. It can also be readily applied to model‐based control approaches (e.g., model predictive control) in future studies. [ABSTRACT FROM AUTHOR]

Efficient p-type doping of III-nitride materials is notoriously difficult due to their large bandgaps, intrinsic n-type doping, and the large ionization energy of acceptors. Specifically, aluminum-containing nitrides such as AlN and AlGaN have demonstrated low p-type conductivity, which increases device resistances and reduces carrier injection in optoelectronic applications. Dilute-anion III-nitride materials are a promising solution for addressing this issue and increasing the activation efficiency of p-type dopants. The upward movement of the valence bands in these materials reduces the ionization energy of the dopants, allowing for enhanced p-type conductivity in comparison to the conventional nitrides. Incorporation of a dilute-arsenic impurity into AlN is hypothesized to significantly reduce the ionization energy of Mg-acceptors from 500 meV to 286 meV, allowing for a two-order magnitude increase in activation efficiency in 6.25%-As AlNAs over that of AlN. [ABSTRACT FROM AUTHOR]

First-principles density functional theory is applied to investigate the electronic and structural properties of dilute-Se β-Ga2(O1−xSex)3 alloys with the Se-content ranging from 0% to 16.67%. The findings showed that the addition of Se has significant effect on the β-Ga2O3 alloy properties. The equilibrium volume and lattice parameters of β-Ga2(O1−xSex)3 alloys are presented, showing a general expansion with increasing Se-content. Further analysis indicates the expansion rate in the c (001) direction is much larger than that in the a and b directions, in which the information provides important guidance for the manufacturing of the β-Ga2(O1−xSex)3/Ga2O3-based material. From our analysis of the band structures, the β-Ga2(O1−xSex)3 alloys exhibit indirect bandgap property with the bandgap energy decreasing dramatically from 4.868 eV to 2.759 eV. The wavelength derived from the direct bandgap energy covers a regime from 255 nm to 475 nm, implying the potential of β-Ga2(O1−xSex)3 alloys in an ultraviolet photodetector and visible light applications. In addition, electron effective masses are calculated and presented for the β-Ga2(O1−xSex)3 alloys, in which the electron effective mass reduces as the Se-content increases. As a part of a highly mismatched alloy semiconductor class, dilute-Se Ga2(O1−xSex)3 is discussed for the first time with no prior literature in our work, and our findings indicate the potential implementation of GaOSe alloys for electronic and optoelectronic device applications. [ABSTRACT FROM AUTHOR]

We report on the electronic properties of β-(InxGa1-x)2O3 alloys with different In-content up to 18.75% using density functional theory (DFT) calculations. The effect of In-content on the band structures as well as the crystal structures of β-(InxGa1-x)2O3 alloys is presented and discussed. Our analysis shows that β-(InxGa1-x)2O3 alloys exhibits indirect gap property, with the band gap reducing from 4.817 eV to 4.422 eV when the In-content increases up to 18.75%. The bandgap energy corresponds to the wavelength region extending from 255 to 280 nm, which implies the possibility for β-(InxGa1-x)2O3 alloys to be applied in the deep UV photodetectors. The electron and heavy hole effective masses are also obtained for the first time based on the band edge dispersions of the β-(InxGa1-x)2O3 materials. Additionally, the effect of band parameters on the impact ionization processes using β-(InxGa1-x)2O3 materials are analyzed. Our new insight regarding the electronic properties indicate the potential of β-(InxGa1-x)2O3 alloys in deep ultraviolet photodetector applications. [ABSTRACT FROM AUTHOR]

The electronic properties of dilute-P AlN1-xPx alloys are investigated by means of First-Principle Density Functional Theory (DFT) calculations, where the phosphorus (P) content is varied from 0% up to 6.25%. Band structure calculations indicate significant modifications of the electronic properties with the introduction of P-atoms, with the possibility of tuning the energy band gap from 6.19eV down to 4.32eV by inserting 6.25% P-content in the AlN-based system. The carrier effective masses and lattice parameters (a and c) were analyzed, and a large bowing parameter of b = 28.3 ± 0.5 eV was found. Moreover, our findings suggest a potential pathway to engineer the valence band crossover between the crystal-field split-off (CH) band and the heavy hole (HH) band by inserting low amounts of P-content (∼1-2%) into the AlN1-xPx alloy. Thus, the dilute-P AlN1-xPx alloys may serve as potential candidates for implementation as the active region material for dominant transverse electric (TE) polarization for deep-UV emitting devices. [ABSTRACT FROM AUTHOR]

The low thermal conductivity of β-Ga2O3 single crystal imposes limitations on its device performance under high-temperature and high-power conditions. Phonons are widely recognized to play the main role in heat transport, while the anharmonic scattering among these quasi-particles significantly diminishes thermal conductivity. Therefore, investigating the anharmonic phonon scattering within β-Ga2O3 single crystal holds paramount significance. In this study, we mainly employed temperature-dependent Raman spectroscopy and first-principles calculation to give a quantitative analysis on the anharmonic phonon scattering. The mode Grüneisen parameters and temperature-dependent thermal expansion coefficient were studied. Strong anharmonic phonon scattering was also confirmed, which was mainly caused by cubic scattering, but quartic scattering is also nonnegligible and causes nonlinear linewidth broadening. Moreover, high wavenumber peaks are more likely to undergo asymmetric phonon scattering by comparing the symmetric and asymmetric scattering models. In all, this study provides a profound understanding of the anharmonic phonon scattering properties within the β-Ga2O3 single crystal. It enriches our understanding of quasi-particle interaction dynamics and offers theoretical pathways for expanding the applications of β-Ga2O3 single crystal and optimizing its device performance. [ABSTRACT FROM AUTHOR]

As a separation process, a paste thickener produces underflow with a high solids concentration. Such underflow leads to a high rake torque which could cause serious operational problems such as underflow blockage, pumping problems and potential donut formation. In this work, a model predictive control approach has been developed to control the underflow solids concentration subject to operational constraints. State observers including linear and extended Kalman filters are studied to determine a cost-effective approach to estimating the solids concentration profile in the paste thickener, which is important for thickener control. A rake torque model is validated with industrial plant data. By utilising the monotonic property of the rake torque model, a linear model predictive control (MPC) approach is developed to deal with the nonlinear constrained control problem. Using an industrial paste thickener as a case study, simulation results demonstrates that the proposed control approach, including an extended Kalman filter, can effectively regulate the underflow solids concentration within permissible operating windows, preventing rake lifting and pumping problems. [ABSTRACT FROM AUTHOR]

Many chemical processes exhibit disparate timescale dynamics with strong coupling between fast, moderate and slow variables. To effectively handle this issue, a model predictive control (MPC) scheme with a non-uniformly spaced optimization horizon is proposed in this paper. This approach implements the time intervals that are small in the near future but large in the distant future, allowing the fast, moderate and slow dynamics to be included in the optimization whilst reducing the number of decision variables. A sufficient condition for ensuring stability for the proposed MPC is developed. The proposed approach is demonstrated using a case study of an industrial paste thickener control problem. While the performance of the proposed approach remains similar to a conventional MPC, it reduces the computational complexity significantly. [ABSTRACT FROM AUTHOR]

In this work, a solar-blind UV photodetector array is fabricated and discussed, based on a metalorganic chemical vapor deposition-grown β-Ga2O3 thin film, toward optical communication application. The high-performance photodetector unit shows a significant photo-to-dark current ratio of 3.4 × 105, a high responsivity of 61.3 A/W, an external quantum efficiency of 3 × 104%, a specific detectivity of 5.2 × 1014 Jones, and a fast response time of 35 ms. In addition, a solar-blind UV/visible light rejection ratio of 2.43 × 102 is achieved, suggesting decent spectral selectivity. For the array, the maximum photocurrent standard deviation is below 12% for every group with a similar layout arrangement. Furthermore, the dark current is at picoampere level, leading to low background noise for the optical communication system. Taking the 50% photocurrent value as the readout threshold line to avoid interference from the exterior meanwhile retaining about 500 on/off cycles, the optical communicated result shows effective outputting information "NJUPT2023" coming from a total of 256 "1" and "0" signals. [ABSTRACT FROM AUTHOR]

Paste thickeners have attracted significant interest from mining industry due to its higher dewatering ability as compared to conventional or high rate thickeners. However, the underflow solids concentration, which is an important process variable of thickeners, is often poorly regulated. In this article, a dynamic model based on sedimentation–consolidation theory is adopted and validated using industrial plant data. Based on this model, control studies have been carried out to explore approaches to address a number of difficulties in current industrial operation. An extended Kalman filter is developed to estimate the compressibility parameter of the feed (coal tailing). As a key process parameter, coal tailing compressibility plays a significant role in thickener dynamics, but is time-varying and difficult to measure. Potential improvements of process operation by implementing model predictive control (MPC) are investigated. Simulation studies show that the proposed control can deliver a higher underflow solids concentration and a better regulated underflow removal rate than the existing operation. It is also demonstrated that taking into account the “future” time-varying input constraints in the MPC algorithm can help overcome the current control difficulty caused by co-disposal of coal tailing and coarse reject. [ABSTRACT FROM AUTHOR]

The dilute-As InyGa1 − yN1 − xAsx alloys are explored by performing first-principles density functional theory (DFT) calculations, where the In-content is varied from 0% up to 18.75% and the As-content is varied from 0% up to 3.13%. The obtained band structures indicate a direct bandgap semiconductor, whose electronic properties are modified significantly by the addition of As-atoms into the InGaN-based system. The lattice parameters (a and c) are analyzed, and the bowing parameters of the dilute-As InGaNAs are analyzed and discussed. The electronic properties indicate the dilute-As InyGa1 − yN1 − xAsx alloys as a potential new material alternative for achieving longer wavelength emission, while utilizing a low In-content (<20%). [ABSTRACT FROM AUTHOR]

Non-orthogonal multiple access (NOMA) emerges as a promising candidate for 5G, which radically alters the way users share the spectrum. In the NOMA system, user clustering (UC) becomes another research issue as grouping the users on different subcarriers with different power levels has a significant impact on spectral utilization. In previous literature, plenty of works have been devoted to solving the UC problem. Recently, the artificial neural network (ANN) has gained considerable attention due to the availability of UC datasets, obtained from the Brute-Force search (BF-S) method. In this paper, deep neural network-based UC (DNN-UC) is employed to effectively characterize the nonlinearity between the cluster formation with channel diversity and transmission powers. Compared to the ANN-UC, the DNN-UC is more competent as UC is a non-convex NP-complete problem, which cannot be entirely captured by the ANN model. In this work, the DNN-UC is first trained with the training samples and then validated with the testing samples to examine its mean square error (MSE) and throughput performance in an asymmetrical fading NOMA channel. Unlike the ANN-UC, the DNN-UC model offers greater room for hyper-parameter optimizations to maximize its learning capability. With the optimized hyper-parameters, the DNN-UC can achieve near-optimal throughput performance, approximately 97% of the throughput of the BF-S method. [ABSTRACT FROM AUTHOR]

Abstract: Prognosis of gear life using the acoustic emission (AE) technique is relatively new in condition monitoring of rotating machinery. This paper describes an experimental investigation on spur gears in which natural pitting was allowed to occur. Throughout the test period, AE, vibration and spectrometric oil samples were monitored continuously in order to correlate and compare these techniques to natural life degradation of the gears. It was observed that based on the analysis of root mean square (rms) levels only the AE technique was more sensitive in detecting and monitoring pitting than either the vibration or spectrometric oil analysis (SOA) techniques. It is concluded that as AE exhibited a direct relationship with pitting progression, it offers the opportunity for prognosis. [Copyright &y& Elsevier]

The practice of engineering as a whole is undergoing major changes especially in dealing with the needs and requirements of advancing IR 4.0 concepts in its discipline. On this note, the 26th Regional Symposium on Chemical Engineering (RSCE 2019) was organized by the Department of Chemical Engineering, Faculty of Engineering, University of Malaya from October 30 to 31, 2019 in Kuala Lumpur, Malaysia. This symposium with the theme "Role of Chemical Engineering in the Era of Industrial Revolution 4.0" had been a great avenue towards dealing with the changes facing the Chemical Engineering society at this present moment. [Extracted from the article]

Abstract: Condition monitoring of gears with vibration analysis is well established whilst the application of acoustic emission (AE) to gear defect diagnosis and monitoring is still in its infancy. This paper details results of an experimental programme to ascertain and validate the applicability of AE to seeded gear defect identification. Furthermore, comparisons are made to vibration diagnosis. As a direct consequence of the experimental programme, the relationship between temperature, oil film thickness and AE activity were investigated. It is shown that similar to the lubricant film thickness between non-conforming surfaces under isothermal conditions, AE activity is not influenced by load. Limitations of applying AE to seeded defect identification are presented and it is concluded that the source of AE activity is attributed to asperity contact. [Copyright &y& Elsevier]

Acoustic emission (AE) is gaining ground as a non-destructive technique for health diagnosis on rotating machinery. There are vast opportunities for development of the AE technique on various forms of rotating machinery, including gearboxes. This paper reviews some recent developments in application of AE to gear defect diagnosis. Furthermore, an experimental investigation that examines the effectiveness of AE for gear defect identification is presented. It is concluded that application of the AE technique to seeded gear defect detection is fraught with difficulties. In addition, the viability of the AE technique for gear defect detection from non-rotating components of a machine is called into question. [Copyright &y& Elsevier]

Background. The aim of this study was to assess the epidemiology of fatty liver in Taiwan. Methods. We retrospectively analyzed the medical records of all patients receiving health examinations at China Medical College Hospital from January through December 2000. A total of 1,012 subjects were included for analysis. Data were analyzed using the t test, chi-square analysis, and multivariate logistic regression. Results. Our cohort was comprised of 41.8% women and 58.2% men; mean age was 49.2 years. The prevalence of fatty liver was 36.9% in all subjects, and prevalence was higher in men than in women. After controlling for other covariates, the multivariate logistic regression analysis showed that the significant factors related to fatty liver were male sex, obesity, hyperglycemia, hypertriglyceridemia, elevated glutamate pyruvate transaminase level, and hyperuricemia. Elevated glutamate oxaloacetate transaminase level was negatively associated with fatty liver. Conclusions. The prevalence of fatty liver is high in Taiwan. This study establishes background data for further investigation. [ABSTRACT FROM AUTHOR]

The article offers information on development in visible light emitting diodes (LED) driven by materials and device innovations. It informs that sharp emissions of nanowires caused due to the formation of quantum states have been used to produce lasers emitting ultraviolet light. It discusses optoelectronic properties of compound AlxGa1?xN and the mechanism of electric current flow in light-emitting devices and lasers.

Concentration polarization is a major challenge to water desalination process. It affects membrane performances by reducing permeate flux and increasing the risk of fouling. One promising approach to reduce concentration polarization is to use external forces such as electro-osmosis. Previously developed reduced-order model either assumed dissolving wall condition, which does not represent the real process mechanism or does not incorporate the effect of electro-osmotic flow (EOF) slip velocity. In this work, we bridge the research gap by proposing a reduced-order model with permeation for membrane systems by considering the effect of EOF slip velocity. The proposed model is shown to provide accurate prediction when compared with computational fluid dynamics (CFD) results. Additionally, the model can complete simulations in seconds, which is 2 orders of magnitude faster as compared to CFD. Using the validated model, we study the mechanism of mixing caused by the slip velocity. Results show that improved mixing and enhanced mass transfer is concentrated in the region between electrodes. We also propose analytical expressions to determine shear stress and pressure drop, which are linked to mass transfer enhancement and energy requirement respectively. This leads us to obtain an optimal electrode spacing to improve mass transfer. • A reduced-order model with varying permeation and electro-osmosis is developed. • The model can complete simulations two orders of magnitude faster than CFD. • Improved mixing and enhanced mass transfer between electrodes • Analytical expressions are proposed to determine shear stress and pressure drop. • The state-space model is used to optimize electrode spacing. [ABSTRACT FROM AUTHOR]

This paper first describes a slow catalytic pyrolysis process used for synthesizing biodiesel from waste cooking oil (WCO) as a feedstock. The influence of variations in the catalyst type (sodium hydroxide and potassium hydroxide), and catalyst concentration (0.5, 1.0, 3.0, 5.0, 7.0 and 10.0% by weight) on both the pyrolysis temperature range and biodiesel yield were investigated. The results suggested that sodium hydroxide (NaOH) was more effective than potassium hydroxide (KOH) as catalysts and that the highest yield (around 70 wt.%) was observed for a NaOH concentration of about 1 wt.% The resultant pyrolysis temperature range was also significantly lower for NaOH catalyst, thus suggesting overall lower energy consumption. Compared to conventional diesel, the synthesized biodiesel exhibited relatively similar physical properties and calorific value. The biodiesel was subsequently blended with diesel fuel in different blend ratios of 0, 20, 40, 60, 80 and 100% by volume of biodiesel and were later tested in a compression ignition engine. Brake thermal efficiency and specific fuel consumption were observed to be worse with biodiesel fuel blends particularly at higher engine load above 50%. However, NOx emission generally decreased with increasing blend ratio across all engine load, with greater reduction observed at higher engine load. Similar observation can also be concluded for CO emission. In contrast, lower hydrocarbon (HC) emission from the biodiesel fuel blends was only observed for blend ratios no higher than 40%. Particulate emission from the biodiesel fuel blends did not pose an issue given its comparable smoke opacity to diesel observed during the engine test. The in-cylinder peak pressures, temperature and heat release rate of biodiesel fuel blends were lower than diesel. Overall, biodiesel fuel blends exhibited shorter ignition delays when compared to diesel fuel. [ABSTRACT FROM AUTHOR]

Presents information on a study that evaluated the distribution of fasting glucose and the relation between hyperglycemia and the cardiovascular risk factors and sociodemographic factors in elderly persons. Methodology; Statistical analysis; Results; Conclusion.

Spintronics devices have been a research hotspot due to their rich theoretical and application value. The widebandgap semiconductor β-Ga2O3 has excellent application potential in spintronics due to the controllability of its electron behavior via ultraviolet light. This paper employs first-principles calculations and the Wenzel–Kramers–Brillouin (WKB) approximation to comprehensively investigate spin transport based on magnetic tunnel junctions (MTJs) comprising β-Ga2O3 nanosheets. The magnetic moment of the ferromagnetic layer in β-Ga2O3 MTJs is found to be positively correlated with tunnel magnetoresistance (TMR). Interestingly, layer-number parity-dependent oscillation of TMR in β-Ga2O3 MTJs is observed, which is explained by the non-equilibrium Green function and the WKB approximation. TMR reaches a maximum of 1077% at five layers, and bias-dependent stability is observed in the monolayer model under biases of 0–20 mV. This study not only expands the application potential of β-Ga2O3 and predicts its superiority in spintronics but also enriches the related condensed matter theory. [ABSTRACT FROM AUTHOR]

The continuous growth in artificial intelligence and high-performance computing has necessitated the development of efficient optoelectronic artificial synapses crucial for neuromorphic computing (NC). Ga2O3 is an emerging wide-bandgap semiconductor with high deep ultraviolet absorption, tunable persistent photoconductivity, and excellent stability toward electric fields, making it a promising component for optoelectronic artificial synapses. Currently reported Ga2O3 optoelectronic artificial synapses often suffer from complex fabrication processes and potential room for improvement due to plasticity. To address the issue of low device plasticity and practical application scenarios, we present an amorphous Ga2O3 (α-GaOx) flexible optoelectronic artificial synapse. This synapse modulates light stimulus signals using electron/oxygen vacancies and optical stimulation and operates as a visual storage device for information processing. We investigate the improvement of the optoelectronic synapses' plasticity by controlling the number of oxygen vacancies via a plasma treatment method and demonstrate its effective application in a three-layer backpropagation neural network for handwritten digit classification. Under the same stimulus conditions, the synaptic weight of samples treated with Ar plasma exhibits a higher rate of change, with the current levels increasing by 2–3 orders of magnitude, achieving greater plasticity. The improved optoelectronic synapses achieved an accuracy of 93.34%/94%, demonstrating their potential as efficient computing solutions and insights for future applications in NC chips. [ABSTRACT FROM AUTHOR]

In this study, we present an investigation of the spontaneous and piezoelectric polarization in the ε-(AlxGa1–x)2O3/ε-Ga2O3 heterostructures using density functional theory calculations. The spontaneous polarization (Psp) was found to increase from 23.93 to 26.34 μC/cm2 when Al-content increase from 0% to 50%. With Al-content increasing, the strain-induced piezoelectric polarization (Ppe) increases, which negates the Psp, causing the total polarization (Ptot) of the epitaxy layer in the AlGaO/GaO heterostructure to remain almost constant across all Al compositions. Additionally, due to the ferroelectric nature of ε-Ga2O3, a high-density polarization-induced two-dimensional electron gas (2DEG) can be formed at the interface of polarization reversed ε-(AlxGa1–x)2O3/ε-Ga2O3 when an electric field is applied. Using the 1D Schrödinger–Poisson model, the 2DEG of polarization reversed ε-(Al0.125Ga0.875)2O3/ε-Ga2O3 was found to be 2.05 × 1014 cm−2, which is nearly ten times larger than that of GaN-based structures. Our work indicates that ε-(AlxGa1–x)2O3/ε-Ga2O3 heterostructure could play a key role attributed to the large polarization and capability in modulating the polarization for high-power electronic and radio frequency device applications. [ABSTRACT FROM AUTHOR]

Low methoxyl (LM) pectin was extracted from pomelo peels using subcritical water in a dynamic mode. The effects of pressure and temperature were analyzed through a face-centred central composite design. Extraction yield and the rate of extraction were found to be predominantly influenced by temperature. Optimization of the subcritical water extraction (SWE) yielded an optimized operating condition of 120 °C and 30 bar with a predicted pectin yield of 18.8%. The corresponding experimental yield was 19.6%, which is in close agreement with the predicted data. The pectin obtained from the optimized condition was further analyzed for its physicochemical properties. The kinetics of the SWE was also evaluated whereby the one-site kinetic desorption model was found to be in good agreement with experimental data ( R 2 > 0.94). [ABSTRACT FROM AUTHOR]

The dilute-As InGaNAs-based quantum well (QW) active region and the corresponding large-overlap design is analyzed by using a self-consistent 6-band $k\cdot p$ method. Our study evaluates the optical transition energy, ground state electron-hole wavefunction overlap, and optical gain characteristics of a dilute-As InGaNAs QW consisting of a 3.3 nm thick In0.19Ga0.81N0.94As0.06 well and 10 nm thick GaN barriers. The calculation suggests that the In0.19Ga0.81N0.94As0.06 QW may result in a transition wavelength and optical gain comparable to a conventional 3.3 nm thick In0.35Ga0.65N QW, while preserving low In-content (~19%). In addition, a staggered dilute-As InGaNAs QW design with a modulated As-doping profile in the InGaNAs QW is presented, and the calculation results in a significantly enhanced wavefunction overlap and optical gain. This study reveals the excellent potential of the dilute-As InGaNAs semiconductor for application as a high efficiency active region material for future long wavelength emitters. [ABSTRACT FROM AUTHOR]

Gallium oxide has been attracting much interest due to its tremendous potential for power device application. The (BxGa1−x)2O3 ternary alloys of monoclinic and orthorhombic phases with the B-content covering the full composition were studied using first-principles density functional theory calculations. The effect of the B-content on the structural and electronic properties of (BxGa1−x)2O3 alloys is discussed. The formation enthalpy of the ternary alloys has been investigated, indicating the feasibility of synthesizing (BxGa1−x)2O3 alloys depending on the specified growth temperature condition. In addition, the increase in the B-content in (BxGa1−x)2O3 alloys generally leads to the decrease in lattice constants, implying possible tensile strain if grown on the Ga2O3 substrate. Our analysis on the electronic properties shows that all (BxGa1−x)2O3 alloys exhibit indirect gap property, in which the bandgap increases from 4.83 eV to 6.86 eV in the monoclinic phase and from 5.32 eV to 11.27 eV in the orthorhombic phase when the B-content increases from 0% to 100%. The band alignment between Ga2O3 and B2O3 in the (100)-direction is also presented, showing a type-II and type-I alignment for monoclinic-based and orthorhombic-based alloys, respectively. Our results showed an extremely large conduction band offset of 5.76 eV between orthorhombic-based Ga2O3 and B2O3 alloys. Our studies regarding the electronic and structural properties provide important insight regarding the potential of (BxGa1−x)2O3 alloys for III-oxide-based electronic and optoelectronic device applications. [ABSTRACT FROM AUTHOR]

Effective filtration of orbital angular momentum (OAM) modes is essential to achieve multiple-channel data transmission in an OAM fiber for telecommunication applications. The nature of helical-shaped OAM wave propagation possessing many topological charges implies the need for uniquely designed index-modulated filters to conform to its twisted propagating direction in the fiber. Here, different from previous structures in demultiplexing OAM modes, a helical-shaped fiber grating structure concept is proposed as a pathway toward efficient demultiplexing of OAM modes in a fiber. A comparison of our proposed structure with the conventional fiber Bragg filter in transmitting an OAM wave shows a stronger reflection of the higher order OAM mode. We suggest that the proposed fiber Bragg structure has strong potential to be used for OAM fiber telecommunication technology. [ABSTRACT FROM AUTHOR]

• A tutorial description of relaxing port-Hamiltonian systems is outlined. • Tracking-error control design without feedback passivation is adapted to non-linear systems. • A sufficient condition for global asymptotic stabilization is proposed. • Illustration of theoretical developments and of control performance/robustness by simulations is included. In this paper, a tracking-error-based control design without feedback passivation stage is developed for the stabilization of physical and chemical nonlinear processes. To achieve control objectives, the system dynamics is first formulated under appropriate conditions as a relaxing (pseudo) port-Hamiltonian (PH) representation with some quadratic storage function, in which the positive semi-definite property of damping matrix may not be taken necessarily into account. Then, a reference trajectory expressed by a certain structure passing through a desired set-point (or containing an optimal profile) is suitably chosen. By adding a relevant damping injection, asymptotic and global convergence of error dynamics is guaranteed. Two case studies including the level control of a four-tank process of continuous time type and the optimal tracking of a batch polymerization reactor of discontinuous time type due to the nature of the process operation are used to illustrate the application and the effectiveness of the approach. Besides the control performance comparison with the conventional passivity-based control method and the robustness evaluation against disturbance and/or noise are included. [ABSTRACT FROM AUTHOR]

The band structure of the dilute-As GaNAs material is explained by the hybridization of localized As-impurity states with the valance band structure of GaN. Our approach employs the use of Density Functional Theory (DFT) calculated band structures, along with experimental results, to determine the localized As-impurity energy level and coupling parameters in the band anti-crossing (BAC) k ∙ p model for N-rich alloys. This model captures the reduction of bandgap with increasing arsenic incorporation and provides a tool for device-level design with the material within the context of the k ∙ p formalism. The analysis extends to calculating the effect of the arsenic impurities on hole (heavy, light and split-off) effective masses and predicting the trend of the bandgap across the entire composition range. [ABSTRACT FROM AUTHOR]