Quantum Dynamics of Mesoscopic Driven Duffing Oscillators

We investigate the nonlinear dynamics of a mesoscopic driven Duffing oscillator in a quantum regime. In terms of Wigner function, we identify the nature of state near the bifurcation point, and analyze the transient process which reveals two distinct stages of quenching and escape. The rate process in the escape stage allows us to extract the transition rate, which displays perfect scaling behavior with the driving distance to the bifurcation point. We numerically determine the scaling exponent, compare it with existing result, and propose open questions to be resolved.Comment: 4 pages, 4 figures; revised version accepted for publication in EP

Deterministic creation and stabilization of entanglement in circuit QED by homodyne-mediated feedback control

In the solid-state circuit QED system and based on the homodyne measurement in dispersive regime, we demonstrate that a homodyne-current-based feedback can create and stabilize highly entangled two-qubit states in the presence of moderate noisy environment. Particularly, we present an extended analysis for the current-based Markovian feedback, which leads to an improved filtered-current-based feedback scheme. We show that this is essential for us to achieve the desirable control effect in present system.Comment: 6 pages, 4 figure

Solid lipid dispersion of calcitriol with enhanced dissolution and stability

AbstractSolid dispersion of calcitriol with lipophilic surfactants and triglycerides was developed by melt-mixing method to modify the release and enhance stability of the drug. The solid dispersions were characterized by differential scanning calorimetry (DSC), hot stage polarized optical microscopy (HSPM), infrared spectroscopy (FTIR) and stability studies. The solid dispersion significantly enhanced the stability of calcitriol, which could be attributed to the high antioxidant activity of the solid lipid dispersion. The rapid dissolution rate from the solid dispersion was attributed to the amorphous or solid solution state of drug with improved specific surface area and wettability than the drug crystals. Therefore, solid dispersion of calcitriol with d-a-tocopheryl polyethylene glycol 1000 succinate (TPGS) offers a good approach to modify the release and enhance stability of calcitriol. The influence of lipophilic solid dispersion on drug bioavailability needs further investigation

Influence of activation temperature and prestress on behavior of Fe-SMA bonded joints

The prestressed strengthening of structures via use of bonded iron-based shape memory alloys (Fe-SMAs) has proven promising, albeit with concerns regarding the temperature dependency of the adhesive properties. In this study, the effect of activation temperature and generated prestress are investigated experimentally. Six Fe-SMA-to-steel adhesively bonded joints, comprising different Fe-SMA strips (non-prestrained and prestrained) and activation strategies (full activation and partial activation), were prepared, activated via electrical resistance heating, and tested under quasi-static loading. It is found that the bond–slip behavior of a joint with activation can be modeled by that of an equivalent non-activated joint. The generated prestress influences the full-range behavior by raising the base tensile stress level of the Fe-SMA strip, with negligible effects on further aspects of the full-range behavior. With the increasing activation temperature, the fracture energy is initially increased and eventually reduced, while the bond capacity and effective bond length are retained almost constant

Fatigue testing and analysis of steel plates manufactured by wire-arc directed energy deposition

Wire-arc directed energy deposition (DED), also known as wire-arc additive manufacturing (WAAM), is a metal 3D printing technique that is recognised for its high efficiency, cost-effectiveness, flexibility in build scales and suitability for the construction sector. However, there remains a lack of fundamental data on the structural performance of WAAM elements, especially regarding their fatigue behaviour. A comprehensive experimental study into the fatigue behaviour of WAAM steel plates has therefore been undertaken and is reported herein. Following geometric, mechanical and microstructural characterisation, a series of WAAM coupons was tested under uniaxial high-cycle fatigue loading. A total of 75 fatigue tests on both as-built and machined coupons, covering various stress ranges and stress ratios (R = 0.1, 0.2, 0.3 and 0.4), have been conducted. The local stress concentrations in the as-built coupons induced by their surface undulations have also been studied by numerical simulations. The fatigue test results were analysed using constant life diagrams (CLDs) and S-N (stress-life) diagrams, based on both nominal and local stresses. The CLDs revealed that the fatigue strength of the as-built WAAM steel was relatively insensitive to the different stress ratios. The S-N diagrams showed that the surface undulations resulted in a reduction of about 35% in the fatigue endurance limit for the as-built WAAM material relative to the machined material, and a reduction of about 60% in fatigue life under the same load level. The as-built and machined WAAM coupons were shown to exhibit similar fatigue behaviour to conventional steel butt welds and S355 structural steel plates, respectively. Preliminary nominal stress-based and local stress-based S-N curves were also proposed for the WAAM steel

Self-prestressing bonded patches using Fe-SMA and CFRP for lifetime extension of fatigue-cracked steel details

Self-prestressing bonded patches employing iron-based shape memory alloy (Fe-SMA) and carbon fiber reinforced polymer (CFRP) for lifetime extension of cracked steel structures are investigated. The repair patches, applicable in confined spaces, are bonded over cracks, with prestress generated within Fe-SMA via activation (heating and cooling) to induce compression on cracks. Experimental tests involve cracked steel plates repaired with Fe-SMA and Fe-SMA/CFRP bonded patches, with a patch width of 50 mm and varied patch lengths of 100[sbnd]500 mm. Fe-SMA strips are activated to 180 ℃ using electric heating, generating prestresses of 154[sbnd]254 MPa. Fatigue tests (∆σ=90 MPa, R=0.2) show fatigue life extensions of ≥4.2 and ≥5.5 times for Fe-SMA and Fe-SMA/CFRP repairs. The 100 mm long Fe-SMA/CFRP patch exhibits optimal performance in lifetime extension, achieving complete crack arrest. As patch lengths decrease, failure modes shift from Fe-SMA (and CFRP) fracture to patch debonding while all patches remain effective in fatigue life extension. Finite element analysis with experimental validation quantifies the effects of prestress and load-sharing on reducing stress intensity factors at crack tips, thus retarding crack propagation. Design recommendations are proposed for the application of self-prestressing patches

Two new species of freshwater goby (Teleostei, Gobiidae) from the Upper Youshui River, Chongqing, China

Two previously unknown species of Rhinogobius have been discovered in the streams of the Upper Youshui River, within the Yuan River Basin, Xiushan County, Chongqing, China. These new species are named as Rhinogobius sudoccidentalis and Rhinogobius lithopolychroma. Phylogenetic analysis based on mitochondrial genomes revealed that R. sudoccidentalis is genetically closest to R. reticulatus, while R. lithopolychroma shares the greatest genetic similarity with R. leavelli. Morphological distinctions allow for the clear differentiation of these species. Rhinogobius sudoccidentalis sp. nov. is characterized by having VI–VII rays in the first dorsal fin and I, 8–9 rays in the second dorsal fin. The longitudinal scale series typically consists of 22–24 scales, while the transverse scale series comprises 7–8 scales. Notably, the predorsal scale series is absent and the total vertebrae count is 12+17=29. Rhinogobius lithopolychroma sp. nov. can be distinguished from other species by the presence of 13–15 rays on the pectoral fin. Its longitudinal scale series ranges from 30 to 33 scales, with no scales in the predorsal area. The total vertebral count is 30, with 12 precaudal and 18 caudal vertebrae. The head and body of this species are light gray with irregular orange markings on the cheeks and opercle. Through morphological and molecular analyses, it has been confirmed that R. lithopolychroma and R. sudoccidentalis represent novel species within the Rhinogobius genus