Parametrizing Quantum States and Channels

This work describes one parametrization of quantum states and channels and several of its possible applications. This parametrization works in any dimension and there is an explicit algorithm which produces it. Included in the list of applications are a simple characterization of pure states, an explicit formula for one additive entropic quantity which does not require knowledge of eigenvalues, and an algorithm which finds one Kraus operator representation for a quantum operation without recourse to eigenvalue and eigenvector calculations. PACS: 03.67a, 03.67-Hk, 03.67-Lx     

Stable inversion and parameter variations

As part of the process of automatically guiding an aircraft, we have been successful in using stable inversion to compute a desired bounded state trajectory and corresponding bounded control. In addition to this feedforward control, we must also construct a regulator to address modeling errors and disturbances. With respect to modeling errors we find that the stable inversion procedures used are so accurate that the regulator can assume a simple form, say a linear regulator about the desired trajectory. We show that under the appropriate assumptions, the bounded state trajectory and bounded control computed through stable inversion depend continuously on the parameters of the system. This is a consequence of a mathematical result that we prove about the continuous dependence of the “particular solution” of a time varying nonlinear system driven by a bounded input. This is distinct from the usual continuous dependence of the initial value problem for systems.     

Structure and Properties of Nano-Scale Oxide-Dispersed Iron

Bulk samples of pure iron and yttria dispersed iron with and without titanium (i.e., Fe, Fe-Y₂O₃, and Fe-Y₂O₃-Ti) were prepared by hot extrusion of high-energy ball-milled powders. An examination of the microstructure using TEM revealed that the addition of titanium resulted in the reduction of the dispersoid size with a concomitant increase in the volume fraction of the dispersoids. As a result, Fe-Y₂O₃-Ti exhibited a substantial increase in hardness and tensile properties as compared to Fe and Fe-Y₂O₃. The higher hardness and strength of Fe-Y₂O₃-Ti is shown to be due to the presence of finer and higher number density of Y-Ti-O complex oxides. Dynamic strain aging in the temperature range of 423 K to 573 K (150 °C to 300 °C) was observed in all the compositions studied.     

Orthogonal design study on factors affecting the diameter of perfluorinated sulfonic acid nanofibers during electrospinning

In this study, Nafion® NR 40 beads with polyethylene oxide (PEO) are fabricated into a nanofiber membrane using electrospinning. In particular, Nafion® beads in non‐toxic mixed solvent (EtOH and H₂O) were blended with the carrier polymer PEO, which is the minor component in the solution responsible for the solution spinnability. The highest content of Nafion® in the nanofiber is 98.04%. To investigate the factors influencing the nanofiber diameter during electrospinning, an orthogonal design method was adopted. These factors include the carrier polymer content, distance between the syringe needle and roller collector, flow rate of the electrospinning solution, and the roller rotation speed. After obtaining the significant factors and optimal test level, an additional optimization experiment is conducted under the best conditions. The resulting nanofibers have a diameter of ～150 nm. Moreover, the obtained Nafion® nanofiber membrane has strong potential for applications in polymer electrolyte membrane fuel cells (PEMFC), the chlor‐alkali industry, catalysts, and metal ion removal. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41755.     

Vapor Phase Selective Catalytic Oxidation of Cyclohexane over 13X Supported Metal Oxides in the Presence of Ozone

This article reports the application of ozone for the selective oxidation of cyclohexane over 13X molecular sieve supported various metal oxides at ambient temperatures. From the SEM, XRD and HR-TEM results, the impregnated metal oxides are highly dispersed on the support. The activity results reveal that Co/MS, Mo/MS, Cu/MS, and Ag/MS catalysts produce cyclohexanone/cyclohexanol as selective oxidation products, whereas Ce/MS, Mn/MS, and V/MS catalysts yield, predominantly, CO and CO₂. Among them, Co/MS catalyst exhibits better conversion of 12.2% with selectively of 58% to cyclohexanone/cyclohexanol, which is attributed to the simultaneous activation of ozone and cyclohexane (-C-H bond) at ambient conditions.     

Minocycline Loaded Hybrid Composites Nanoparticles for Mesenchymal Stem Cells Differentiation into Osteogenesis

Bone transplants are used to treat fractures and increase new tissue development in bone tissue engineering. Grafting of massive implantations showing slow curing rate and results in cell death for poor vascularization. The potentials of biocomposite scaffolds to mimic extracellular matrix (ECM) and including new biomaterials could produce a better substitute for new bone tissue formation. A purpose of this study is to analyze polycaprolactone/silk fibroin/hyaluronic acid/minocycline hydrochloride (PCL/SF/HA/MH) nanoparticles initiate human mesenchymal stem cells (MSCs) proliferation and differentiation into osteogenesis. Electrospraying technique was used to develop PCL, PCL/SF, PCL/SF/HA and PCL/SF/HA/MH hybrid biocomposite nanoparticles and characterization was analyzed by field emission scanning electron microscope (FESEM), contact angle and Fourier transform infrared spectroscopy (FT-IR). The obtained results proved that the particle diameter and water contact angle obtained around 0.54 ± 0.12 to 3.2 ± 0.18 µm and 43.93 ± 10.8° to 133.1 ± 12.4° respectively. The cell proliferation and cell-nanoparticle interactions analyzed using (3-(4,5-dimethyl thiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium inner salt) MTS assay (Promega, Madison, WI, USA), FESEM for cell morphology and 5-Chloromethylfluorescein diacetate (CMFDA) dye for imaging live cells. Osteogenic differentiation was proved by expression of osteocalcin, alkaline phosphatase activity (ALP) and mineralization was confirmed by using alizarin red (ARS). The quantity of cells was considerably increased in PCL/SF/HA/MH nanoparticles when compare to all other biocomposite nanoparticles and the cell interaction was observed more on PCL/SF/HA/MH nanoparticles. The electrosprayed PCL/SF/HA/MH biocomposite nanoparticle significantly initiated increased cell proliferation, osteogenic differentiation and mineralization, which provide huge potential for bone tissue engineering.     

Enhanced airborne sound absorption effect in poly(vinylidene fluoride)/(K0.5Na0.5)NbO3-nanofiber composite foams

Introducing electrical conductive function to discharge local piezoelectric effect is found effective for improving airborne sound absorption performance. In this work, instead of conductive fillers, a composite with two piezoelectric materials with opposite piezoelectric responses was explored aiming at enhanced sound absorption effect. Open-cell poly(vinylidene fluoride)/(K_0.5Na_0.5)NbO₃ (PVDF/KNN)-nanofiber composite foams were proposed and investigated for airborne sound absorption purpose. Structural and thermal analyses showed that the KNN nanofibers were well dispersed in the PVDF matrix and enhanced the degree of crystallinity of polar phase of PVDF. Significantly enhanced airborne sound absorption over a broad frequency range was observed in the PVDF/KNN-nanofiber composite foams, with increasing KNN nanofibers. One possible mechanism for the improved sound absorption with the piezoelectric KNN nanofibers with positive piezoelectric coefficient added in the PVDF matrix with negative piezoelectric coefficient is that electrical discharge could be facilitated for energy dissipation with the opposite charges generated through the piezoelectric effects in the two phases with opposite polarity. The experimental results show that the open-cell PVDF/KNN-nanofiber composite foams are promising for broadband airborne sound absorption application, and our analysis shed a light on the strategy in designing piezoelectric composite foam with high sound absorption performance.     

Recent studies on electrospinning preparation of patterned,core–shell,and aligned scaffolds

Electrospinning is one of the most important ways to prepare continuous, high porosity, large specific surface area, and uniform diameter micro‐ and nanoscale fibers. So, it has been widely used in the preparation of micro/nano‐sized polymer scaffolds for tissue engineering in recent years. In addition to the versatility in material selection and the processing variables, electrospinning also provides a lot of methods to regulate fiber structure and scaffolds morphology. For example, the near‐field electrospinning can provide a method to solve the problem of uncontrollable fiber path; the melt electrospinning eliminates the risk of solvent residue in the construct; the addition of different auxiliary electrodes can make the fiber patterned. This review introduces the underlying principle and characteristics of above electrospinning applied in biomedicine. Herein, we highlight a comprehensive understanding of the technical aspect of this technology for versatile fibers with patterned, core–shell and aligned morphology. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46570.     

High Speed Particle Beam Generation: A Dynamic Focusing Mechanism for Selecting Ultrafine Particles

RSMS-II is a unique characterization technique for analyzing the chemical content of individual airborne ultrafine particles in real time. Although based on earlier versions, the newest implementation offers crucial enhancements including a smart data acquisition system and a completely redesigned particle inlet. The particle inlet is based on a dynamic focusing mechanism that selectively transmits a narrow particle size range in the form of a high speed particle beam. The mean particle size that is optimally transmitted is dynamically altered by changing the nozzle source pressure, thus particles over a wide size range may be selected. Inherent in the design of dynamic focusing mechanisms is the ability to size-select particles based on their aerodynamic characteristics, thus obviating the need for additional sizing components. The principle, design, and calibration of a variable pressure inlet is presented in the current work. Characteristics are estimated employing a theoretical approach based on the Stokes number definition and supported with numerical simulations using CFD tools. Results from a preliminary effort in calibrating the inlet using monodisperse aerosol are presented. Results indicate that the size resolving capability of the inlet may be enhanced at the expense of lowered transmission rates. Finally, the capability of RSMS-II as a characterization technique is demonstrated by analyzing ultrafine atmospheric particles from a moderately polluted episode.     

Nanostructured ceramics for biomedical implants

Recent progress in the synthesis, characterization, and biological compatibility of nanostructured ceramics for biomedical implants is reviewed. A major goal is to develop ceramic coating technology that can reduce the friction and wear in mating total joint replacement components, thus contributing to their significantly improved function and longer life span. Particular attention is focused on the enhancement of mechanical properties such as hardness, toughness, and friction coefficient and on the bioactivity as they pertain to the nanostructure of the material. The development of three nanostructured implant coatings is discussed: diamond, hydroxyapatite, and functionally graded metalloceramics based on the Cr-Ti-N ternary system. Nanostructured diamond produced by chemical vapor deposition (CVD) techniques and composed of nano-size diamond grains have particular promise because of the combination of ultrahigh hardness, improved toughness over conventional microcrystalline diamond, low friction, and good adhesion to titanium alloys. Nanostructured processing applied to hydroxyapatite coatings is used to achieve the desired mechanical characteristics and enhanced surface reactivity and has been found to increase osteoblast adhesion, proliferation, and mineralization. Finally, nanostructured metalloceramic coatings provide continuous variation from a nanocrystalline metallic bond at the interface to the hard ceramic bond on the surface and have the ability to overcome adhesion problems associated with ceramic hard coatings on metallic substrates.