Proposal for a High-Speed Optical Dark-Soliton Detector Using a Microring Resonator

This letter presents a theoretical study of a novel application of a simple waveguide-based microring resonator as a high-speed optical dark-soliton detector. The microring resonator is described by a z-transform transfer function that consists of one zero and one pole. When the resonator has a zero equal to unity (or is at resonance) and a pole equal to 0.81, it can convert a dark-soliton signal into a Gaussian-like return-to-zero signal with a power level that is ~20 dB greater than that of the existing interferometer-based scheme. The proposed scheme also has a simpler structure than the integrator-based method     

Optical Switching Networks With Minimum Number of Limited-Range Wavelength Converters

We study the problem of determining the minimum number of limited-range wavelength converters needed to construct strictly, wide-sense, and rearrangeably nonblocking optical cross-connects for both unicast and multicast traffic patterns. We give the exact formula to compute this number for rearrangeably and wide-sense nonblocking cross-connects under both the unicast and multicast cases. We also give optimal cross-connect constructions with respect to the number of limited-range wavelength converters.     

Gestalt-based feature similarity measure in trademark database

Motivated by the studies in Gestalt principle, this paper describes a novel approach on the adaptive selection of visual features for trademark retrieval. We consider five kinds of visual saliencies: symmetry, continuity, proximity, parallelism and closure property. The first saliency is based on Zernike moments, while the others are modeled by geometric elements extracted illusively as a whole from a trademark. Given a query trademark, we adaptively determine the features appropriate for retrieval by investigating its visual saliencies. We show that in most cases, either geometric or symmetric features can give us good enough accuracy. To measure the similarity of geometric elements, we propose a maximum weighted bipartite graph (WBG) matching algorithm under transformation sets which is found to be both effective and efficient for retrieval.     

Creating new water-soluble Iso- and n-fatty acid arginate hydrochloride with antimicrobial properties

Typically, short- and long-chain lipids from oils exhibit different antimicrobial activities and therefore have been used in agriculture and aquaculture, biomedical therapeutic and antibacterial fields. However, these fatty acids have limitations in terms of bioactive efficacy, thermostability and aqueous solubility. In this study, water-soluble iso-fatty acid arginate hydrochloride derivatives with antimicrobial properties were produced by introducing branched (iso-) chain and other linear- (n-) chain fatty acids to the “arginine” amino acid molecule. The two-step synthetic route was straightforward and provided an efficient 88% and 76% product yields for ethyl n-oleoyl arginate hydrochloride and ethyl iso-oleoyl arginate hydrochloride, respectively. ATR-FT-IR, NMR, and LC-MS-Q-TOF techniques were used to thoroughly characterize and confirm the products. These arginate products had strong antimicrobial activities against Listeria innucua, a Gram-positive bacterium with minimum inhibitory concentrations and minimum bactericidal concentrations ranging from 1.8 µg mL⁻¹ to 29.1 µg mL⁻¹. Therefore, the study demonstrated the development of a novel class of antimicrobial compounds from iso-fatty acids and arginates.     

Chemical Biology Approaches to Understanding Neuronal O−GlcNAcylation

O-linked β-N-acetylglucosamine (O−GlcNAc) is a ubiquitous post-translational modification in mammals, decorating thousands of intracellular proteins. O−GlcNAc cycling is an essential regulator of myriad aspects of cell physiology and is dysregulated in numerous human diseases. Notably, O−GlcNAcylation is abundant in the brain and numerous studies have linked aberrant O−GlcNAc signaling to various neurological conditions. However, the complexity of the nervous system and the dynamic nature of protein O−GlcNAcylation have presented challenges for studying of neuronal O−GlcNAcylation. In this context, chemical approaches have been a particularly valuable complement to conventional cellular, biochemical, and genetic methods to understand O−GlcNAc signaling and to develop future therapeutics. Here we review selected recent examples of how chemical tools have empowered efforts to understand and rationally manipulate O−GlcNAcylation in mammalian neurobiology.     

Electrospinning of ultrafine non-hydrolyzed silk sericin/PEO fibers on PLA: A bilayer scaffold fabrication

We report the feasibility of electrospinning of protein-polymer multilayered scaffolds with selected materials such as non-hydrolyzed silk sericin (SS), polyethylene oxide (PEO), and polylactic acid (PLA), with tuned fiber size and properties for each layer. We present a new innovative way for the electrospinning (ES) of non-hydrolyzed SS mixed with PEO yielding fibers with an average diameter ranging between 120 and 150 nm. Different SS:PEO ratios have been electrospun to study the effect of the concentration of SS protein on the fibers size and shape, as well and their electrospinnability. Electrospun SS:PEO fibers display weak to no mechanical resistance (non-measurable) and their deposition onto a sturdier scaffold is necessary to allow their use in biomedical and/or pharmaceutical fields. Therefore, bilayer scaffolds have been fabricated consisting of a PLA support and SS:PEO fibers obtained from the optimized SS:PEO ratio (1.2:4). They are composed of a sturdy hydrophobic layer of PLA fibers and a layer of sticky hydrophilic SS:PEO fibers. The scaffolds have been characterized extensively by Fourier transforms infra-red (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and their resistance to mechanical stress. Finally, hydrophobicity of both layers has been determined by measuring the contact angle of water droplets on the scaffolds, further proving the bilayer nature of the scaffolds.     

Evaluation of pressure and viscous drags of a rising bubble at small Reynolds numbers

Journal of Mechanical Science and Technology - Pressure and viscous drags acting on a bubble rising in a viscous fluid are numerically estimated to obtain the corresponding drag coefficients that...     

Enhanced microwave absorption features of Ba3Co2Fe24O41 hexaferrite by high lanthanium doping concentration

Controlling material structure and its electromagnetic properties, including complex permittivity and permeability, could enhance the microwave absorption performance of the material in terms of reflection loss and effective absorption bandwidth. In this study, La-substituted barium hexaferrite, Ba_3−xLa_xCo₂Fe₂₄O₄₁ (x = 0, 0.1, 0.3, and 0.5) compounds were successfully prepared using the solid-state reaction method, and their corresponding microstructures, static magnetic properties, and electromagnetic features in 2–18 GHz were investigated. The doping of La content increased saturation magnetization, coercivity, and remnant magnetization. The Ba_2.7La_0.3Co₂Fe₂₄O₄₁ epoxied sample with 3.5 mm thickness possessed an excellent microwave absorption of −47.3 dB at 3.52 GHz, and its corresponding effective absorption bandwidths were 3.75 GHz (2.25–6 GHz) and 0.57 GHz (17.43–18 GHz). It is shown that doping with various La concentrations on Ba₃Co₂Fe₂₄O₄₁ can be used as an effective technique to tune the performance of microwave absorbers based on barium hexaferrite.     

Achieving Ultrahigh Electron Mobility in PdSe2 Field-Effect Transistors via Semimetal Antimony as Contacts

Even though atomically thin 2D semiconductors have shown great potential for next-generation electronics, the low carrier mobility caused by poor metal–semiconductor contacts and the inherently high density of impurity scatterings remains a critical issue. Herein, high-mobility field-effect transistors (FETs) by introducing few-layer PdSe₂ flakes as channels is achieved, via directly depositing semimetal antimony (Sb) as drain–source electrodes. The formation of clean and defect-free van der Waals (vdW) stackings at the Sb–PdSe₂ heterointerfaces boosts the room temperature transport characteristics, including low contact resistance down to 0.55 kΩ µm, high on-current density reaching 96 µA µm⁻¹, and high electron mobility of 383 cm² V⁻¹ s⁻¹. Furthermore, metal–insulator transition (MIT) is observed in the PdSe₂ FETs with and without hexagonal boron nitride (h–BN) as buffer layers. However, the layered h–BN/PdSe₂ vdW stacking eliminates the interference of interfacial disorders, and thus the corresponding device exhibits a lower MIT crossing point, larger mobility exponent of γ ∼ 1.73, significantly decreased hopping parameter of T₀, and ultrahigh electron mobility of 2,184 cm² V⁻¹ s⁻¹ at 10 K. These findings are expected to be significant for developing high mobility 2D-based quantum devices.     

Adaptive neural network hierarchical sliding mode control for six degrees of freedom overhead crane

This paper presents an effective control method for three-dimensional (3D) overhead cranes with six degrees of freedom (DOF). Two payload swings and an axial payload oscillation should be minimized besides driving the bridge, trolley, and hoisting drum to bring the payload to the desired position in space. First, a novel 3D-6DOF crane model is developed, where the sixth degree of freedom is axial cargo oscillation that has never been considered in previous studies. A controller is then designed using the hierarchical sliding mode control method. Moreover, a radial basis function neural network (RBFNN) is used to approximate the system's unknown dynamic model accurately. According to the Lyapunov principle, a control law and an updated law for the neural network's weight matrices are designed to ensure the stability of the closed-loop system. Simulation results on Matlab software show the proposed approach's effectiveness, such as smaller swing, minor axial oscillation, and precise position as desired.