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Sample records for high-q microsphere cavity

  1. Confocal microscopy and spectroscopy of nanocrystals on a high-Q microsphere resonator

    International Nuclear Information System (INIS)

    Goetzinger, S; Menezes, L de S; Benson, O; Talapin, D V; Gaponik, N; Weller, H; Rogach, A L; Sandoghdar, V

    2004-01-01

    We report on experiments where we used a home-made confocal microscope to excite single nanocrystals on a high-Q microsphere resonator. In that way spectra of an individual quantum emitter could be recorded. The Q factor of the microspheres coated with nanocrystals was still up to 10 9 . We also demonstrate the use of a prism coupler as a well-defined output port to collect the fluorescence of an ensemble of nanocrystals coupled to whispering-gallery modes

  2. Macroscopic quantum electrodynamics of high-Q cavities

    Energy Technology Data Exchange (ETDEWEB)

    Khanbekyan, Mikayel

    2009-10-27

    In this thesis macroscopic quantum electrodynamics in linear media was applied in order to develop an universally valid quantum theory for the description of the interaction of the electromagnetic field with atomic sources in high-Q cavities. In this theory a complete description of the characteristics of the emitted radiation is given. The theory allows to show the limits of the applicability of the usually applied theory. In order to establish an as possible generally valid theory first the atom-field interaction was studied in the framework of macroscopic quantum electrodynamics in dispersive and absorptive media. In order to describe the electromagnetic field from Maxwell's equations was started, whereby the noise-current densities, which are connected with the absorption of the medium, were included. The solution of these equations expresses the electromagnetic field variables by the noise-current densities by means of Green's tensor of the macroscopic Maxwell equations. The explicit quantization is performed by means of the noise-current densities, whereby a diagonal Hamiltonian is introduced, which then guarantees the time development according to Maxwell's equation and the fulfillment of the fundamental simultaneous commutation relations of the field variables. In the case of the interaction of the medium-supported field with atoms the Hamiltonian must be extended by atom-field interactions energies, whereby the canonical coupling schemes of the minimal or multipolar coupling can be used. The dieelectric properties of the material bodies as well as their shape are coded in the Green tensor of the macroscopic Maxwell equations. As preparing step first the Green tensor was specified in order to derive three-dimensional input-output relations for the electromagnetic field operators on a plane multilayer structure. Such a general dewscription of the electromagnetic field allows the inclusion both of dispersion and absorption of the media and the

  3. Macroscopic quantum electrodynamics of high-Q cavities

    International Nuclear Information System (INIS)

    Khanbekyan, Mikayel

    2009-01-01

    In this thesis macroscopic quantum electrodynamics in linear media was applied in order to develop an universally valid quantum theory for the description of the interaction of the electromagnetic field with atomic sources in high-Q cavities. In this theory a complete description of the characteristics of the emitted radiation is given. The theory allows to show the limits of the applicability of the usually applied theory. In order to establish an as possible generally valid theory first the atom-field interaction was studied in the framework of macroscopic quantum electrodynamics in dispersive and absorptive media. In order to describe the electromagnetic field from Maxwell's equations was started, whereby the noise-current densities, which are connected with the absorption of the medium, were included. The solution of these equations expresses the electromagnetic field variables by the noise-current densities by means of Green's tensor of the macroscopic Maxwell equations. The explicit quantization is performed by means of the noise-current densities, whereby a diagonal Hamiltonian is introduced, which then guarantees the time development according to Maxwell's equation and the fulfillment of the fundamental simultaneous commutation relations of the field variables. In the case of the interaction of the medium-supported field with atoms the Hamiltonian must be extended by atom-field interactions energies, whereby the canonical coupling schemes of the minimal or multipolar coupling can be used. The dieelectric properties of the material bodies as well as their shape are coded in the Green tensor of the macroscopic Maxwell equations. As preparing step first the Green tensor was specified in order to derive three-dimensional input-output relations for the electromagnetic field operators on a plane multilayer structure. Such a general dewscription of the electromagnetic field allows the inclusion both of dispersion and absorption of the media and the possible

  4. Numerical and Experimental Study of the Q Factor of High-Q Micropillar Cavities

    DEFF Research Database (Denmark)

    Gregersen, Niels; Reitzenstein, S.; Kistner, C.

    2010-01-01

    Micropillar cavities are potential candidates for high-efficiency single-photon sources and are testbeds for cavity quantum electrodynamics experiments. In both applications a high quality (Q) factor is desired. It was recently shown that the Q of high-Q semiconductor micropillar cavities exhibit...

  5. High-Q perpendicular-biased ferrite-tuned cavity

    International Nuclear Information System (INIS)

    Carlini, R.D.; Thiessen, H.A.; Potter, J.M.

    1983-01-01

    Rapid-cycling proton synchrotrons, such as the proposed LAMPF II accelerator, require approximately 10 MV per turn rf with 17% tuning range near 50 MHz. The traditional approach to ferrite-tuned cavities uses a ferrite which is longitudinally biased (rf magnetic field parallel to bias field). This method leads to unacceptably high losses in the ferrite. At Los Alamos, we are developing a cavity with transverse bias (rf magnetic field perpendicular to the bias field) that makes use of the tensor permeability of the ferrite. Modest power tests of a small (10-cm-dia) quarter-wave singly re-entrant cavity tuned by nickel-zinc ferrites and aluminum-doped garnets indicate that the losses in the ferrite can be made negligible compared with the losses due to the surface resistivity of the copper cavity at power levels from 2 to 200 watts

  6. MEASUREMENT OF HIGH Q RF CAVITY IMPEDANCE WITH BEAM

    International Nuclear Information System (INIS)

    Limborg, Cecile

    2003-01-01

    An inexpensive method to measure, with beam, the Rs and Q of narrow-band high order resonances in RF cavities was developed on SPEAR. The two main results of this study are: (1) an improved operational stability of SPEAR; and (2) the decision to keep the present cavities for the proposed SPEAR upgrade. SPEAR3 will be run initially at 200 mA, twice the present current. Just beyond the current threshold, and before step loss, there is a regime in which the beam performs large amplitude, low frequency oscillations. Detailed measurements were performed to characterize the frequency, amplitude, growth and damping time of these relaxation oscillations

  7. High-Q superconducting niobium cavities for gravitational wave detectors

    International Nuclear Information System (INIS)

    De Paula, L A N; Furtado, S R; Aguiar, O D; N F Oliveira Jr, N F Oliveira Jr; Castro, P J; Barroso, J J

    2014-01-01

    The main purpose of this work is to optimize the electric Q-factor of superconducting niobium klystron cavities to be used in parametric transducers of the Mario Schenberg gravitational wave detector. Many cavities were manufactured from niobium with relatively high tantalum impurities (1420 ppm) and they were cryogenically tested to determine their resonance frequencies, unloaded electrical quality factors (Q 0 ) and electromagnetic couplings. These cavities were closed with a flat niobium plate with tantalum impurities below 1000 ppm and an unloaded electrical quality factors of the order of 10 5 have been obtained. AC conductivity of the order of 10 12 S/m has been found for niobium cavities when matching experimental results with computational simulations. These values for the Q-factor would allow the detector to reach the quantum limit of sensitivity of ∼ 10 −22 Hz −1/2 in the near future, making it possible to search for gravitational waves around 3.2 kHz. The experimental tests were performed at the laboratories of the National Institute for Space Research (INPE) and at the Institute for Advanced Studies (IEAv - CTA)

  8. High-Q cavity-induced synchronization in oscillator arrays

    DEFF Research Database (Denmark)

    Filatrella, Giovanni; Pedersen, Niels Falsig; Wiesenfeld, Kurt

    2000-01-01

    A model for a large number of Josephson junctions coupled to a cavity is presented. The system displays synchronization behavior very similar to that reported in recent experiments [P. Barbara ct al., Phys. Rev. Lett. 82, 1963 (1999)]. The essential dynamical mechanism responsible for coherence...

  9. High-Q microsphere resonators for angular velocity sensing in gyroscopes

    International Nuclear Information System (INIS)

    An, Panlong; Zheng, Yongqiu; Yan, Shubin; Xue, Chenyang; Liu, Jun; Wang, Wanjun

    2015-01-01

    A resonator gyroscope based on the Sagnac effect is proposed using a core unit that is generated by water-hydrogen flame melting. The relationship between the quality factor Q and diameter D is revealed. The Q factor of the spectral lines of the microsphere cavity coupling system, which uses tapered fibers, is found to be 10 6 or more before packaging with a low refractive curable ultraviolet polymer, although it drops to approximately 10 5 after packaging. In addition, a rotating test platform is built, and the transmission spectrum and discriminator curves of a microsphere cavity with Q of 3.22×10 6 are measured using a semiconductor laser (linewidth less than 1 kHz) and a real-time proportional-integral circuit tracking and feedback technique. Equations fitting the relation between the voltage and angular rotation rate are obtained. According to the experimentally measured parameters, the sensitivity of the microsphere-coupled system can reach 0.095 ∘ /s

  10. High-Q silicon-on-insulator slot photonic crystal cavity infiltrated by a liquid

    International Nuclear Information System (INIS)

    Caër, Charles; Le Roux, Xavier; Cassan, Eric

    2013-01-01

    We report the experimental realization of a high-Q slot photonic crystal cavity in Silicon-On-Insulator (SOI) configuration infiltrated by a liquid. Loaded Q-factor of 23 000 is measured at telecom wavelength. The intrinsic quality factor inferred from the transmission spectrum is higher than 200 000, which represents a record value for slot photonic crystal cavities on SOI, whereas the maximum of intensity of the cavity is roughly equal to 20% of the light transmitted in the waveguide. This result makes filled slot photonic crystal cavities very promising for silicon-based light emission and ultrafast nonlinear optics

  11. The combination of high Q factor and chirality in twin cavities and microcavity chain

    Science.gov (United States)

    Song, Qinghai; Zhang, Nan; Zhai, Huilin; Liu, Shuai; Gu, Zhiyuan; Wang, Kaiyang; Sun, Shang; Chen, Zhiwei; Li, Meng; Xiao, Shumin

    2014-01-01

    Chirality in microcavities has recently shown its bright future in optical sensing and microsized coherent light sources. The key parameters for such applications are the high quality (Q) factor and large chirality. However, the previous reported chiral resonances are either low Q modes or require very special cavity designs. Here we demonstrate a novel, robust, and general mechanism to obtain the chirality in circular cavity. By placing a circular cavity and a spiral cavity in proximity, we show that ultra-high Q factor, large chirality, and unidirectional output can be obtained simultaneously. The highest Q factors of the non-orthogonal mode pairs are almost the same as the ones in circular cavity. And the co-propagating directions of the non-orthogonal mode pairs can be reversed by tuning the mode coupling. This new mechanism for the combination of high Q factor and large chirality is found to be very robust to cavity size, refractive index, and the shape deformation, showing very nice fabrication tolerance. And it can be further extended to microcavity chain and microcavity plane. We believe that our research will shed light on the practical applications of chirality and microcavities. PMID:25262881

  12. High-Q Defect-Free 2D Photonic Crystal Cavity from Random Localised Disorder

    Directory of Open Access Journals (Sweden)

    Kelvin Chung

    2014-07-01

    Full Text Available We propose a high-Q photonic crystal cavity formed by introducing random disorder to the central region of an otherwise defect-free photonic crystal slab (PhC. Three-dimensional finite-difference time-domain simulations determine the frequency, quality factor, Q, and modal volume, V, of the localized modes formed by the disorder. Relatively large Purcell factors of 500–800 are calculated for these cavities, which can be achieved for a large range of degrees of disorders.

  13. Coherent stacking of picosecond laser pulses in a high-Q optical cavity for accelerator applications

    International Nuclear Information System (INIS)

    Androsov, V.P.; Karnaukhov, I.M.; Telegin, Yu.N.

    2007-01-01

    We have performed the harmonic analysis of the steady-state coherent pulse-stacking process in a high-Q Fabry-Perot cavity. The expression for the stacked pulse shape is obtained as a function of both the laser cavity and pulse-stacking cavity parameters. We have also estimated the pulse power gains attainable in the laser-optical system of NESTOR storage ring, which is under development at Kharkov Institute of Physics and Technology. It is shown that high power gains (∼10 4 ) can be, in principle, achieved in a cavity, formed with low-absorption, high reflectivity (R ∼ 0.9999) mirrors, if the laser cavity length will differ exactly by half wavelength from the pulse-stacking cavity length. It implies development of the sophisticated frequency stabilization loop for maintaining the cavity length constant within a sub-nanometer range. At the same time, power gains of ∼10 3 can be obtained with medium reflectivity mirrors (R ∼ 0.999) at considerably lower cost

  14. On-chip spectroscopy with thermally tuned high-Q photonic crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Liapis, Andreas C., E-mail: andreas.liapis@gmail.com; Gao, Boshen; Siddiqui, Mahmudur R. [The Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Shi, Zhimin [Department of Physics, University of South Florida, Tampa, Florida 33620 (United States); Boyd, Robert W. [The Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Department of Physics and School of Electrical Engineering and Computer Science, University of Ottawa, Ottawa, Ontario K1N 6N5 (Canada)

    2016-01-11

    Spectroscopic methods are a sensitive way to determine the chemical composition of potentially hazardous materials. Here, we demonstrate that thermally tuned high-Q photonic crystal cavities can be used as a compact high-resolution on-chip spectrometer. We have used such a chip-scale spectrometer to measure the absorption spectra of both acetylene and hydrogen cyanide in the 1550 nm spectral band and show that we can discriminate between the two chemical species even though the two materials have spectral features in the same spectral region. Our results pave the way for the development of chip-size chemical sensors that can detect toxic substances.

  15. Effects of finite temperature on two-photon transitions in a Rydberg atom in a high-Q cavity

    International Nuclear Information System (INIS)

    Puri, R.R.; Joshi, A.

    1989-01-01

    The effects of cavity temperature on an effective two-level atom undergoing two-photon transitions in a high-Q cavity are investigated. The quantum statistical properties of the field and the dynamical properties of the atom in this case are studied and compared with those for an atom making one-photon transitions between the two levels. The analysis is based on the solution of the equation for the density matrix in the secular approximation which is known to be a valid approximation in the case of a Rydberg atom in a high-Q cavity. (orig.)

  16. Observation of the fundamental Nyquist noise limit in an ultra-high Q-factor cryogenic bulk acoustic wave cavity

    Energy Technology Data Exchange (ETDEWEB)

    Goryachev, Maxim, E-mail: maxim.goryachev@uwa.edu.au; Ivanov, Eugene N.; Tobar, Michael E. [ARC Centre of Excellence for Engineered Quantum Systems, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Kann, Frank van [School of Physics, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia); Galliou, Serge [Department of Time and Frequency, FEMTO-ST Institute, ENSMM, 26 Chemin de l' Épitaphe, 25000 Besançon (France)

    2014-10-13

    Thermal Nyquist noise fluctuations of high-Q bulk acoustic wave cavities have been observed at cryogenic temperatures with a DC superconducting quantum interference device amplifier. High Q modes with bandwidths of few tens of milliHz produce thermal fluctuations with a signal-to-noise ratio of up to 23 dB. The estimated effective temperature from the Nyquist noise is in good agreement with the physical temperature of the device, confirming the validity of the equivalent circuit model and the non-existence of any excess resonator self-noise. The measurements also confirm that the quality factor remains extremely high (Q > 10{sup 8} at low order overtones) for very weak (thermal) system motion at low temperatures, when compared to values measured with relatively strong external excitation. This result represents an enabling step towards operating such a high-Q acoustic device at the standard quantum limit.

  17. Proof-of-principle demonstration of Nb3Sn superconducting radiofrequency cavities for high Q0 applications

    Science.gov (United States)

    Posen, S.; Liepe, M.; Hall, D. L.

    2015-02-01

    Many future particle accelerators require hundreds of superconducting radiofrequency (SRF) cavities operating with high duty factor. The large dynamic heat load of the cavities causes the cryogenic plant to make up a significant part of the overall cost of the facility. This contribution can be reduced by replacing standard niobium cavities with ones coated with a low-dissipation superconductor such as Nb3Sn. In this paper, we present results for single cell cavities coated with Nb3Sn at Cornell. Five coatings were carried out, showing that at 4.2 K, high Q0 out to medium fields was reproducible, resulting in an average quench field of 14 MV/m and an average 4.2 K Q0 at quench of 8 × 109. In each case, the peak surface magnetic field at quench was well above Hc1, showing that it is not a limiting field in these cavities. The coating with the best performance had a quench field of 17 MV/m, exceeding gradient requirements for state-of-the-art high duty factor SRF accelerators. It is also shown that—taking into account the thermodynamic efficiency of the cryogenic plant—the 4.2 K Q0 values obtained meet the AC power consumption requirements of state-of-the-art high duty factor accelerators, making this a proof-of-principle demonstration for Nb3Sn cavities in future applications.

  18. Two-dimensional Josephson junction arrays coupled through a high-Q cavity

    DEFF Research Database (Denmark)

    Filatrella, G.; Pedersen, Niels Falsig; Wiesenfeld, K.

    2001-01-01

    the cavity. The highly resonant cavity induces synchronized behavior, which is qualitatively different than what is familiar from other studies on nonlinear oscillator arrays, for example the Kuramoto model. We also address the effects of disorder, as well as the role of detuning between the spontaneous...

  19. Radio frequency regenerative oscillations in monolithic high-Q/V heterostructured photonic crystal cavities

    International Nuclear Information System (INIS)

    Yang, Jinghui; Gu, Tingyi; Zheng, Jiangjun; Wei Wong, Chee; Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee

    2014-01-01

    We report temporal and spectral domain observation of regenerative oscillation in monolithic silicon heterostructured photonic crystals cavities with high quality factor to mode volume ratios (Q/V). The results are interpreted by nonlinear coupled mode theory (CMT) tracking the dynamics of photon, free carrier population, and temperature variations. We experimentally demonstrate effective tuning of the radio frequency tones by laser-cavity detuning and laser power levels, confirmed by the CMT simulations with sensitive input parameters

  20. Optimization of High-Q Coupled Nanobeam Cavity for Label-Free Sensing

    OpenAIRE

    Yaseen, Mohammad; Yang, Yi-Chun; Shih, Min-Hsiung; Chang, Yia-Chung

    2015-01-01

    We numerically and experimentally investigated the lateral coupling between photonic crystal (PhC) nanobeam (NB) cavities, pursuing high sensitivity and figure of merit (FOM) label-free biosensor. We numerically carried out 3D finite-difference time-domain (3D-FDTD) and the finite element method (FEM) simulations. We showed that when two PhC NB cavities separated by a small gap are evanescently coupled, the variation in the gap width significantly changes the coupling efficiency between the ...

  1. High-Q Fabry–Pérot Micro-Cavities for High-Sensitivity Volume Refractometry

    Directory of Open Access Journals (Sweden)

    Noha Gaber

    2018-01-01

    Full Text Available This work reports a novel structure for a Fabry–Pérot micro cavity that combines the highest reported quality factor for an on-chip Fabry–Pérot resonator that exceeds 9800, and a very high sensitivity for an on-chip volume refractometer based on a Fabry–Pérot cavity that is about 1000 nm/refractive index unit (RIU. The structure consists of two cylindrical Bragg micromirrors that achieve confinement of the Gaussian beam in the plan parallel to the chip substrate, while for the perpendicular plan, external fiber rod lenses (FRLs are placed in the optical path of the input and the output of the cavity. This novel structure overcomes number of the drawbacks presented in previous designs. The analyte is passed between the mirrors, enabling its detection from the resonance peak wavelengths of the transmission spectra. Mixtures of ethanol and deionized (DI-water with different ratios are used as analytes with different refractive indices to exploit the device as a micro-opto-fluidic refractometer. The design criteria are detailed and the modeling is based on Gaussian-optics equations, which depicts a scenario closer to reality than the usually used ray-optics modeling.

  2. High-Q, high gradient niobium-coated cavities at CERN

    CERN Document Server

    Calatroni, Sergio; Darriulat, Pierre; Peck, M A; Valente, A M; Van't Hof, C A

    1999-01-01

    Superconducting cavities made by sputter-deposition of a thin niobium film onto copper have proven over the years to be a viable alternative to bulk niobium, the best example being the very successful operation of LEP at 200 GeV. It will be shown that this technology, investigated at 1.5 GHz by a dedicated R&D effort at CERN, can be developed to unprecedented performance, proving that no fundamental limitation prevents high quality factors to be maintained over a broad range of accelerating field.

  3. High-Q submicron-diameter quantum-dot microcavity pillars for cavity QED experiments

    DEFF Research Database (Denmark)

    Gregersen, Niels; Lermer, Matthias; Dunzer, Florian

    As/AlAs micropillar design where Bloch-wave engineering is employed to significally enhance the cavity mode confinement in the submicron diameter regime. We demonstrate a record-high vacuum Rabi splitting of 85 µeV of the strong coupling for pillars incorporating quantum dots with modest oscillator strength f ≈ 10....... It is well-known that light-matter interaction depends on the photonic environment, and thus proper engineering of the optical mode in microcavity systems is central to obtaining the desired functionality. In the strong coupling regime, the visibility of the Rabi splitting is described by the light...... coupling in micropillars relied on quantum dots with high oscillator strengths f > 50, our advanced design allows for the observation of strong coupling for submicron diameter quantum dot-pillars with standard f ≈ 10 oscillator strength. A quality factor of 13600 and a vacuum Rabi splitting of 85 µe...

  4. A high-Q low threshold thulium-doped silica microsphere laser in the 2 μm wavelength region designed for gas sensing applications

    International Nuclear Information System (INIS)

    Pal, Atasi; Chen, Shu Ying; Sun, Tong; Grattan, K T V; Sen, Ranjan

    2013-01-01

    A high-Q and low threshold laser resonator, operating in the 2 μm wavelength region, has been demonstrated by coupling a thulium-doped silica microsphere to a tapered fibre. Microspheres with diameters ranging from fifty to a few hundred micrometres were carefully fabricated for this purpose by melting an etched-clad thulium-doped silica fibre tip using a focused beam from a CO 2 laser, while the tapered fibre with waist diameter in the desired range of 2 μm was fabricated by using heating and stretching of standard single-mode telecommunication fibre. The tapered fibre served the dual purpose of transporting pump power into the sphere and allowing the extraction of the resulting laser emission. Under excitation at a wavelength of ∼1.6 μm, lasing occurred at wavelengths over the range from 1.9 to 2.0 μm. Single-mode laser operation was obtained by exciting the fundamental whispering gallery mode resonance of the microsphere, while multi-mode lasing occurred for non-fundamental mode excitation. The threshold power of the laser was measured to be about 50 μW delivered pump power, and a maximum laser power of 0.8 mW at around 1.94 μm was observed for a 6 mW pump power, operating at wavelengths around 1.6 μm. The laser was designed as a low threshold and compact source for miniaturized gas sensing devices operating over this important wavelength region. (letter)

  5. High-Q AlAs/GaAs adiabatic micropillar cavities with submicron diameters for cQED experiments

    DEFF Research Database (Denmark)

    Lermer, M.; Gregersen, Niels; Dunzer, F.

    Quantum dot (QD) micropillar cavities represent an interesting class of microresonator systems aiming at the observation and application of cavity quantum electrodynamics (cQED) on a semiconductor platform. They combine valuable properties i.e. a highly directional and approximately Gaussian shaped...

  6. FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): Teleportation of Entangled States through Divorce of Entangled Pair Mediated by a Weak Coherent Field in a High-Q Cavity

    Science.gov (United States)

    Cardoso B., W.; Almeida G. de, N.

    2008-07-01

    We propose a scheme to partially teleport an unknown entangled atomic state. A high-Q cavity, supporting one mode of a weak coherent state, is needed to accomplish this process. By partial teleportation we mean that teleportation will occur by changing one of the partners of the entangled state to be teleported. The entangled state to be teleported is composed by one pair of particles, we called this surprising characteristic of maintaining the entanglement, even when one of the particle of the entangled pair being teleported is changed, of divorce of entangled states.

  7. Teleportation of Entangled States through Divorce of Entangled Pair Mediated by a Weak Coherent Field in a High-Q Cavity

    International Nuclear Information System (INIS)

    Cardoso, W. B.; Almeida, N. G. de

    2008-01-01

    We propose a scheme to partially teleport an unknown entangled atomic state. A high-Q cavity, supporting one mode of a weak coherent state, is needed to accomplish this process. By partial teleportation we mean that teleportation will occur by changing one of the partners of the entangled state to be teleported. The entangled state to be teleported is composed by one pair of particles, we called this surprising characteristic of maintaining the entanglement, even when one of the particle of the entangled pair being teleported is changed, of divorce of entangled states. (fundamental areas of phenomenology (including applications))

  8. Teleportation of Entangled States through Divorce of Entangled Pair Mediated by a Weak Coherent Field in a High-Q Cavity

    Institute of Scientific and Technical Information of China (English)

    W. B. Cardosol; N. G. de Almeida

    2008-01-01

    We propose a scheme to partially teleport an unknown entangled atomic state. A high-Q cavity, supporting one mode of a weak coherent state, is needed to accomplish this process. By partial teleportation we mean that teleportation will occur by changing one of the partners of the entangled state to be teleported. The entangled state to be teleported is composed by one pair of particles, we called this surprising characteristic of maintaining the entanglement, even when one of the particle of the entangled pair being teleported is changed, of divorce of entangled states.

  9. High sensitivity and high Q-factor nanoslotted parallel quadrabeam photonic crystal cavity for real-time and label-free sensing

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Daquan [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); State Key Laboratory of Information Photonics and Optical Communications, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China); School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Kita, Shota; Wang, Cheng; Lončar, Marko [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Liang, Feng; Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); Tian, Huiping; Ji, Yuefeng [State Key Laboratory of Information Photonics and Optical Communications, School of Information and Communication Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2014-08-11

    We experimentally demonstrate a label-free sensor based on nanoslotted parallel quadrabeam photonic crystal cavity (NPQC). The NPQC possesses both high sensitivity and high Q-factor. We achieved sensitivity (S) of 451 nm/refractive index unit and Q-factor >7000 in water at telecom wavelength range, featuring a sensor figure of merit >2000, an order of magnitude improvement over the previous photonic crystal sensors. In addition, we measured the streptavidin-biotin binding affinity and detected 10 ag/mL concentrated streptavidin in the phosphate buffered saline solution.

  10. Plasmonic reflectors and high-Q nano-cavities based on coupled metal-insulator-metal waveguides

    Directory of Open Access Journals (Sweden)

    Jing Chen

    2012-03-01

    Full Text Available Based on the contra-directional coupling, a composite structure consisting of two coupled metal-insulator-metal (MIM waveguides is proposed to act as an attractive plasmonic reflector. By introducing a defect into one of the MIM waveguides, we show that such a composite structure can be operated as a plasmonic nanocavity with a high quality factor. Both symmetric and anti-symmetric cavity modes are supported in the plasmonic cavity, and their resonance frequencies can be tuned by controlling the defect width. The present structures could have a significant impact for potential applications such as surface plasmon mirrors, filters and solid-state cavity quantum electrodynamics.

  11. The Path to High Q-Factors in Superconducting Accelerating Cavities: Flux Expulsion and Surface Resistance Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Martinello, Martina [Illinois Inst. of Technology, Chicago, IL (United States)

    2016-12-01

    Accelerating cavities are devices resonating in the radio-frequency (RF) range used to accelerate charged particles in accelerators. Superconducting accelerating cavities are made out of niobium and operate at the liquid helium temperature. Even if superconducting, these resonating structures have some RF driven surface resistance that causes power dissipation. In order to decrease as much as possible the power losses, the cavity quality factor must be increased by decreasing the surface resistance. In this dissertation, the RF surface resistance is analyzed for a large variety of cavities made with different state-of-the-art surface treatments, with the goal of finding the surface treatment capable to return the highest Q-factor values in a cryomodule-like environment. This study analyzes not only the superconducting properties described by the BCS surface resistance, which is the contribution that takes into account dissipation due to quasi-particle excitations, but also the increasing of the surface resistance due to trapped flux. When cavities are cooled down below their critical temperature inside a cryomodule, there is always some remnant magnetic field that may be trapped increasing the global RF surface resistance. This thesis also analyzes how the fraction of external magnetic field, which is actually trapped in the cavity during the cooldown, can be minimized. This study is performed on an elliptical single-cell horizontally cooled cavity, resembling the geometry of cavities cooled in accelerator cryomodules. The horizontal cooldown study reveals that, as in case of the vertical cooldown, when the cooling is performed fast, large thermal gradients are created along the cavity helping magnetic flux expulsion. However, for this geometry the complete magnetic flux expulsion from the cavity equator is more difficult to achieve. This becomes even more challenging in presence of orthogonal magnetic field, that is easily trapped on top of the cavity equator

  12. The path to high Q-factors in superconducting accelerating cavities: Flux expulsion and surface resistance optimization

    Science.gov (United States)

    Martinello, Martina

    Accelerating cavities are devices resonating in the radio-frequency (RF) range used to accelerate charged particles in accelerators. Superconducting accelerating cavities are made out of niobium and operate at the liquid helium temperature. Even if superconducting, these resonating structures have some RF driven surface resistance that causes power dissipation. In order to decrease as much as possible the power losses, the cavity quality factor must be increased by decreasing the surface resistance. In this dissertation, the RF surface resistance is analyzed for a large variety of cavities made with different state-of-the-art surface treatments, with the goal of finding the surface treatment capable to return the highest Q-factor values in a cryomodule-like environment. This study analyzes not only the superconducting properties described by the BCS surface resistance, which is the contribution that takes into account dissipation due to quasi-particle excitations, but also the increasing of the surface resistance due to trapped flux. When cavities are cooled down below their critical temperature inside a cryomodule, there is always some remnant magnetic field that may be trapped increasing the global RF surface resistance. This thesis also analyzes how the fraction of external magnetic field, which is actually trapped in the cavity during the cooldown, can be minimized. This study is performed on an elliptical single-cell horizontally cooled cavity, resembling the geometry of cavities cooled in accelerator cryomodules. The horizontal cooldown study reveals that, as in case of the vertical cooldown, when the cooling is performed fast, large thermal gradients are created along the cavity helping magnetic flux expulsion. However, for this geometry the complete magnetic flux expulsion from the cavity equator is more difficult to achieve. This becomes even more challenging in presence of orthogonal magnetic field, that is easily trapped on top of the cavity equator

  13. High-Q operation of superconducting rf cavities: Potential impact of thermocurrents on the rf surface resistance

    Directory of Open Access Journals (Sweden)

    J.-M. Vogt

    2015-04-01

    Full Text Available For many new accelerator applications, superconducting radio frequency systems are the enabling technology. In particular for CW applications, much effort is being expended to minimize the power dissipation (surface resistance of niobium cavities. Starting in 2009, we suggested a means of reducing the residual resistance by performing a thermal cycle [O. Kugeler et al., in Proceedings of the 14th International Conference on RF Superconductivity (2009, p. 352], a procedure of warming up a cavity after initial cooldown to about 20 K and cooling it down again. In subsequent studies [J. M. Vogt, O. Kugeler, and J. Knobloch, Phys. Rev. ST Accel. Beams 16, 102002 (2013], this technique was used to manipulate the residual resistance by more than a factor of 2. It was postulated that thermocurrents during cooldown generate additional trapped magnetic flux that impacts the cavity quality factor. Here, we present a more extensive study that includes measurements of two additional passband modes and that confirms the effect. In this paper, we also discuss simulations that support the claim. While the layout of the cavity LHe tank system is cylindrically symmetric, we show that the temperature dependence of the material parameters results in a nonsymmetric current distribution. Hence a significant amount of magnetic flux can be generated at the rf surface.

  14. Proof-of-principle demonstration of Nb{sub 3}Sn superconducting radiofrequency cavities for high Q{sub 0} applications

    Energy Technology Data Exchange (ETDEWEB)

    Posen, S., E-mail: sep93@cornell.edu; Liepe, M.; Hall, D. L. [Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York 14853 (United States)

    2015-02-23

    Many future particle accelerators require hundreds of superconducting radiofrequency (SRF) cavities operating with high duty factor. The large dynamic heat load of the cavities causes the cryogenic plant to make up a significant part of the overall cost of the facility. This contribution can be reduced by replacing standard niobium cavities with ones coated with a low-dissipation superconductor such as Nb{sub 3}Sn. In this paper, we present results for single cell cavities coated with Nb{sub 3}Sn at Cornell. Five coatings were carried out, showing that at 4.2 K, high Q{sub 0} out to medium fields was reproducible, resulting in an average quench field of 14 MV/m and an average 4.2 K Q{sub 0} at quench of 8 × 10{sup 9}. In each case, the peak surface magnetic field at quench was well above H{sub c1}, showing that it is not a limiting field in these cavities. The coating with the best performance had a quench field of 17 MV/m, exceeding gradient requirements for state-of-the-art high duty factor SRF accelerators. It is also shown that—taking into account the thermodynamic efficiency of the cryogenic plant—the 4.2 K Q{sub 0} values obtained meet the AC power consumption requirements of state-of-the-art high duty factor accelerators, making this a proof-of-principle demonstration for Nb{sub 3}Sn cavities in future applications.

  15. Development of a broadband reflective T-filter for voltage biasing high-Q superconducting microwave cavities

    International Nuclear Information System (INIS)

    Hao, Yu; Rouxinol, Francisco; LaHaye, M. D.

    2014-01-01

    We present the design of a reflective stop-band filter based on quasi-lumped elements that can be utilized to introduce large dc and low-frequency voltage biases into a low-loss superconducting coplanar waveguide (CPW) cavity. Transmission measurements of the filter are seen to be in good agreement with simulations and demonstrate insertion losses greater than 20 dB in the range of 3–10 GHz. Moreover, transmission measurements of the CPW's fundamental mode demonstrate that loaded quality factors exceeding 10 5 can be achieved with this design for dc voltages as large as 20 V and for the cavity operated in the single-photon regime. This makes the design suitable for use in a number of applications including qubit-coupled mechanical systems and circuit QED

  16. Efficient continuous-wave nonlinear frequency conversion in high-Q gallium nitride photonic crystal cavities on silicon

    Directory of Open Access Journals (Sweden)

    Mohamed Sabry Mohamed

    2017-03-01

    Full Text Available We report on nonlinear frequency conversion from the telecom range via second harmonic generation (SHG and third harmonic generation (THG in suspended gallium nitride slab photonic crystal (PhC cavities on silicon, under continuous-wave resonant excitation. Optimized two-dimensional PhC cavities with augmented far-field coupling have been characterized with quality factors as high as 4.4 × 104, approaching the computed theoretical values. The strong enhancement in light confinement has enabled efficient SHG, achieving a normalized conversion efficiency of 2.4 × 10−3 W−1, as well as simultaneous THG. SHG emission power of up to 0.74 nW has been detected without saturation. The results herein validate the suitability of gallium nitride for integrated nonlinear optical processing.

  17. Interaction between beam control and rf feedback loops for high Q cavities an heavy beam loading. Revision A

    International Nuclear Information System (INIS)

    Mestha, L.K.; Kwan, C.M.; Yeung, K.S.

    1994-04-01

    An open-loop state space model of all the major low-level rf feedback control loops is derived. The model has control and state variables for fast-cycling machines to apply modern multivariable feedback techniques. A condition is derived to know when exactly we can cross the boundaries between time-varying and time-invariant approaches for a fast-cycling machine like the Low Energy Booster (LEB). The conditions are dependent on the Q of the cavity and the rate at which the frequency changes with time. Apart from capturing the time-variant characteristics, the errors in the magnetic field are accounted in the model to study the effects on synchronization with the Medium Energy Booster (MEB). The control model is useful to study the effects on beam control due to heavy beam loading at high intensities, voltage transients just after injection especially due to time-varying voltages, instability thresholds created by the cavity tuning feedback system, cross coupling between feedback loops with and without direct rf feedback etc. As a special case we have shown that the model agrees with the well known Pedersen model derived for the CERN PS booster. As an application of the model we undertook a detailed study of the cross coupling between the loops by considering all of them at once for varying time, Q and beam intensities. A discussion of the method to identify the coupling is shown. At the end a summary of the identified loop interactions is presented

  18. Tailoring of the free spectral range and geometrical cavity dispersion of a microsphere by a coating layer.

    Science.gov (United States)

    Ristić, Davor; Mazzola, Maurizio; Chiappini, Andrea; Rasoloniaina, Alphonse; Féron, Patrice; Ramponi, Roberta; Righini, Giancarlo C; Cibiel, Gilles; Ivanda, Mile; Ferrari, Maurizio

    2014-09-01

    The modal dispersion of a whispering gallery mode (WGM) resonator is a very important parameter for use in all nonlinear optics applications. In order to tailor the WGM modal dispersion of a microsphere, we have coated a silica microsphere with a high-refractive-index coating in order to study its effect on the WGM modal dispersion. We used Er(3+) ions as a probe for a modal dispersion assessment. We found that, by varying the coating thickness, the geometrical cavity dispersion can be used to shift overall modal dispersion in a very wide range in both the normal and anomalous dispersion regime.

  19. Group Delay of High Q Antennas

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert Frølund

    2013-01-01

    Group Delay variations versus frequency is an essential factor which can cause distortion and degradation in the signals. Usually this is an issue in wideband communication systems, such as satellite communication systems, which are used for transmitting wideband data. However, group delay can also...... become an issue, when working with high Q antennas, because of the steep phase shift over the frequency. In this paper, it is measured how large group delay variations can become, when going from a low Q antenna to a high Q antenna. The group delay of a low Q antenna is shown to be around 1.3 ns, whereas...... a high Q antenna has group delay of around 22 ns. It is due to this huge group delay variation characteristics of high Q antennas, that signal distortion might occur in the radio system with high Q antennas....

  20. Biosensing by WGM Microspherical Resonators

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2016-06-01

    Full Text Available Whispering gallery mode (WGM microresonators, thanks to their unique properties, have allowed researchers to achieve important results in both fundamental research and engineering applications. Among the various geometries, microspheres are the simplest 3D WGM resonators; the total optical loss in such resonators can be extremely low, and the resulting extraordinarily high Q values of 108–109 lead to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. They can also be coated in order to better control their properties or to increase their functionality. Their very high sensitivity to changes in the surrounding medium has been exploited for several sensing applications: protein adsorption, trace gas detection, impurity detection in liquids, structural health monitoring of composite materials, detection of electric fields, pressure sensing, and so on. In the present paper, after a general introduction to WGM resonators, attention is focused on spherical microresonators, either in bulk or in bubble format, to their fabrication, characterization and functionalization. The state of the art in the area of biosensing is presented, and the perspectives of further developments are discussed.

  1. Thermal Loss in High-Q Antennas

    DEFF Research Database (Denmark)

    Barrio, Samantha Caporal Del; Bahramzy, Pevand; Svendsen, Simon

    2014-01-01

    Tunable antennas are very promising for future generations of mobile communications, where antennas are required to cover a wide range operating bands. This letter aims at characterizing the loss mechanism of tunable antennas. Tunable antennas typically exhibit a high Quality factor (Q), which ca...... lead to thermal loss due to the conductivity of the metal. The investigation shows that copper loss is non-negligible for high Q values. In the proposed design the copper loss is 2 dB, for a Q of 260 at 700 MHz....

  2. Twin photon pairs in a high-Q silicon microresonator

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, Steven; Lu, Xiyuan [Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627 (United States); Jiang, Wei C. [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Lin, Qiang, E-mail: qiang.lin@rochester.edu [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States); Department of Electrical and Computer Engineering, University of Rochester, Rochester, New York 14627 (United States)

    2015-07-27

    We report the generation of high-purity twin photon pairs through cavity-enhanced non-degenerate four-wave mixing (FWM) in a high-Q silicon microdisk resonator. Twin photon pairs are created within the same cavity mode and are consequently expected to be identical in all degrees of freedom. The device is able to produce twin photons at telecommunication wavelengths with a pair generation rate as large as (3.96 ± 0.03) × 10{sup 5} pairs/s, within a narrow bandwidth of 0.72 GHz. A coincidence-to-accidental ratio of 660 ± 62 was measured, the highest value reported to date for twin photon pairs, at a pair generation rate of (2.47 ± 0.04) × 10{sup 4} pairs/s. Through careful engineering of the dispersion matching window, we have reduced the ratio of photons resulting from degenerate FWM to non-degenerate FWM to less than 0.15.

  3. A fast way for calculating longitudinal wakefields for high Q resonances

    International Nuclear Information System (INIS)

    Cheng-Yang Tan and James M Steimel

    2001-01-01

    We have come up with a way for calculating longitudinal wakefields for high Q resonances by mapping the wake functions to a two dimension vector space. Then in this space, a transformation which is basically a scale change and a rotation, allows us to calculate the new wakefield by knowing only one previous wakefield and one previous particle passage through the cavity. We will also compare this method to the brute force method which needs to know all the passages of the previous particles through the cavity

  4. High Q diamond hemispherical resonators: fabrication and energy loss mechanisms

    International Nuclear Information System (INIS)

    Bernstein, Jonathan J; Bancu, Mirela G; Bauer, Joseph M; Cook, Eugene H; Kumar, Parshant; Nyinjee, Tenzin; Perlin, Gayatri E; Ricker, Joseph A; Teynor, William A; Weinberg, Marc S; Newton, Eric

    2015-01-01

    We have fabricated polycrystalline diamond hemispheres by hot-filament CVD (HFCVD) in spherical cavities wet-etched into a high temperature glass substrate CTE matched to silicon. Hemispherical resonators 1.4 mm in diameter have a Q of up to 143 000 in the fundamental wineglass mode, for a ringdown time of 2.4 s. Without trimming, resonators have the two degenerate wineglass modes frequency matched as close as 2 Hz, or 0.013% of the resonant frequency (∼16 kHz). Laser trimming was used to match resonant modes on hemispheres to 0.3 Hz. Experimental and FEA energy loss studies on cantilevers and hemispheres examine various energy loss mechanisms, showing that surface related losses are dominant. Diamond cantilevers with a Q of 400 000 and a ringdown time of 15.4 s were measured, showing the potential of polycrystalline diamond films for high Q resonators. These resonators show great promise for use as hemispherical resonant gyroscopes (HRGs) on a chip. (paper)

  5. Detuning effect study of High-Q Mobile Phone Antennas

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert F.

    2015-01-01

    Number of frequency bands that have to be covered by smart phones, are ever increasing. This broadband coverage can be obtained either by using a low-Q antenna or a high-Q tunable antenna. This study investigates high-Q antennas performance when placed in proximity of the user. This study...

  6. Selective tuning of high-Q silicon photonic crystal nanocavities via laser-assisted local oxidation.

    Science.gov (United States)

    Chen, Charlton J; Zheng, Jiangjun; Gu, Tingyi; McMillan, James F; Yu, Mingbin; Lo, Guo-Qiang; Kwong, Dim-Lee; Wong, Chee Wei

    2011-06-20

    We examine the cavity resonance tuning of high-Q silicon photonic crystal heterostructures by localized laser-assisted thermal oxidation using a 532 nm continuous wave laser focused to a 2.5 μm radius spot-size. The total shift is consistent with the parabolic rate law. A tuning range of up to 8.7 nm is achieved with ∼ 30 mW laser powers. Over this tuning range, the cavity Qs decreases from 3.2×10(5) to 1.2×10(5). Numerical simulations model the temperature distributions in the silicon photonic crystal membrane and the cavity resonance shift from oxidation.

  7. Coupling single NV-centres to high-Q whispering gallery modes of a preselected frequency-matched microresonator

    International Nuclear Information System (INIS)

    Schietinger, Stefan; Benson, Oliver

    2009-01-01

    In this paper, we report the controlled coupling of fluorescence from a single NV-centre in a single nanodiamond to the high-Q modes of a preselected microsphere. Microspheres from an ensemble with a finite size distribution can be characterized precisely via white light Mie-scattering. The mode spectrum of individual spheres can be determined with high precision. A sphere with an appropriate spectrum can be selected, and a nanodiamond containing a single NV-centre can be coupled to it. The spectral position of the calculated lowest order whispering gallery modes are found to be in very good agreement with the experimentally observed resonances of the coupled fluorescence from the single NV-re.

  8. Microradiographic microsphere manipulator

    International Nuclear Information System (INIS)

    Singleton, R.M.

    1980-01-01

    A method and apparatus are provided for radiographic characterization of small hollow spherical members (microspheres), constructed of either optically transparent or opaque materials. The apparatus involves a microsphere manipulator which holds a batch of microspheres between two parallel thin plastic films for contact microradiographic characterization or projection microradiography thereof. One plastic film is translated to relative to and parallel to the other to roll the microspheres through any desired angle to allow different views of the microspheres

  9. Op-amp gyrator simulates high Q inductor

    Science.gov (United States)

    Sutherland, W. C.

    1977-01-01

    Gyrator circuit consisting of dual operational amplifier and four resistors inverts impedance of capacitor to simulate inductor. Synthetic inductor has high Q factor, good stability, wide bandwidth, and easily determined value of inductance that is independent of frequency. It readily lends itself to integrated-circuit applications, including filter networks.

  10. High-Q Bandpass Comb Filter for Mains Interference Extraction

    Directory of Open Access Journals (Sweden)

    Neycheva T.

    2009-12-01

    Full Text Available This paper presents a simple digital high-Q bandpass comb filter for power-line (PL or other periodical interference extraction. The filter concept relies on a correlated signal average resulting in alternating constructive and destructive spectrum interference i.e. the so-called comb frequency response. The presented filter is evaluated by Matlab simulations with real ECG signal contaminated with low amplitude PL interference. The made simulations show that this filter accurately extract the PL interference. It has high-Q notches only at PL odd harmonics and is appropriate for extraction of any kind of odd harmonic interference including rectangular shape. The filter is suitable for real-time operation with popular low-cost microcontrollers.

  11. Photoluminescence and lasing in whispering gallery mode glass microspherical resonators

    Energy Technology Data Exchange (ETDEWEB)

    Ristić, D. [Ruđer Bošković Institute, Division of Materials Physics, Laboratory for Molecular Physics, Bijenička c. 54, Zagreb (Croatia); Center of Excellence for Advanced Materials and Sensing Devices, Research unit New Functional Materials, Bijenička c. 54, Zagreb (Croatia); Berneschi, S.; Camerini, M. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Farnesi, D.; Pelli, S. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy); Trono, C. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Chiappini, A.; Chiasera, A.; Ferrari, M. [CSMFO Group, Istituto di Fotonica e Nanotecnologie, IFN-CNR, Via alla Cascata 56/C, 38050 Povo-Trento (Italy); Lukowiak, A. [Institute of Low Temperature and Structure Research, PAS, ul. Okolna 2, Wroclaw 50-950 (Poland); Dumeige, Y.; Féron, P. [Laboratoire d' Optronique, (CNRS-UMR 6082-Foton), ENSSAT, 6 rue de Kérampont, 22300 Lannion (France); Righini, G.C. [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy); Soria, S., E-mail: s.soria@ifac.cnr.it [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Conti, G. Nunzi [IFAC-CNR Istituto di Fisica Applicata, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Centro Studi e Ricerche ' E. Fermi' , Piazza del Viminale 2, 00184 Roma (Italy)

    2016-02-15

    We report experimental results regarding the development of Er{sup 3+}-doped glass microspherical cavities for the fabrication of compact sources at 1.55 μm. We investigate several different approaches in order to fabricate the microspheres including direct melting of Er{sup 3+}-doped glass powders, synthesis of Er{sup 3+}-doped monolithic microspheres by drawing Er{sup 3+}-doped glass, and coating of silica microspheres with an Er{sup 3+}-doped sol–gel layer. Details of the different fabrication processes are presented together with the photoluminescence characterization in free space configuration of the microspheres and of the glass precursor. We have analyzed the photoluminescence spectra of the whispering gallery modes of the microspheres excited using evanescent coupling and we demonstrate tunable laser action in a wide range of wavelengths around 1.55 μm. As much as 90 μW of laser output power was measured in Er{sup 3+}-doped glass microspheres. - Highlights: • Different approaches in microsphere fabrication and various types of post-processing. • Trimming of photorefractive glass microsphere lasers with UV light. • Peak power record of 90 μW by pumping at 1480 nm.

  12. High-Q microwave photonic filter with a tuned modulator.

    Science.gov (United States)

    Capmany, J; Mora, J; Ortega, B; Pastor, D

    2005-09-01

    We propose the use of tuned electro-optic or electroabsorption external modulators to implement high-quality (high-Q) factor, single-bandpass photonic filters for microwave signals. Using this approach, we experimentally demonstrate a transversal finite impulse response with a Q factor of 237. This is to our knowledge the highest value ever reported for a passive finite impulse-response microwave photonic filter.

  13. High-Q microwave resonators with a photonic crystal structure

    International Nuclear Information System (INIS)

    Schuster, M.

    2001-08-01

    The localisation of electromagnetic energy at a defect in a photonic crystal is similar to a well known effect employed to construct high-Q microwave resonators: In a whispering gallery (WHG-) mode resonator the high Q-factor is achieved by localisation of the electromagnetic field energy by total reflection inside a disk made of dielectric material. The topic of this work is to demonstrate, that WHG-like modes can exist in an air defect in a photonic crystal that extends over several lattice periods; and that a high-Q microwave resonator can be made, utilizing these resonant modes. In numerical simulations, the transmission properties of a photonic crystal structure with hexagonal lattice symmetry have been investigated with a transfer-matrix-method. The eigenmodes of a defect structure in a photonic crystal have been calculated with a quasi-3d finite element integration technique. Experimental results confirm the simulated transmission properties and show the existence of modes inside the band gap, when a defect is introduced in the crystal. Resonator measurements show that a microwave resonator can be operated with those defect modes. It was found out that the main losses of the resonator were caused by bad microwave properties of the used dielectric material and by metal losses on the top and bottom resonator walls. Furthermore, it turned out that the detection of the photonic crystal defect mode was difficult because of a lack of simulation possibilities and high housing mode density in the resonator. (orig.)

  14. High Q-factor tunable superconducting HF circuit

    CERN Document Server

    Vopilkin, E A; Pavlov, S A; Ponomarev, L I; Ganitsev, A Y; Zhukov, A S; Vladimirov, V V; Letyago, A G; Parshikov, V V

    2001-01-01

    Feasibility of constructing a high Q-factor (Q approx 10 sup 5) mechanically tunable in a wide range of frequencies (12-63 MHz) vibration circuit of HF range was considered. The tunable circuit integrates two single circuits made using YBaCuO films. The circuit frequency is tuned by changing distance X (capacity) between substrates. Potentiality of using substrates of lanthanum aluminate, neodymium gallate and strontium titanate for manufacture of single circuits was considered. Q-factor of the circuit amounted to 68000 at resonance frequency of 6.88 MHz

  15. High Q-factor tunable superconducting HF circuit

    International Nuclear Information System (INIS)

    Vopilkin, E.A.; Parafin, A.E.; Pavlov, S.A.; Ponomarev, L.I.; Ganitsev, A.Yu.; Zhukov, A.S.; Vladimirov, V.V.; Letyago, A.G.; Parshikov, V.V.

    2001-01-01

    Feasibility of constructing a high Q-factor (Q ∼ 10 5 ) mechanically tunable in a wide range of frequencies (12-63 MHz) vibration circuit of HF range was considered. The tunable circuit integrates two single circuits made using YBaCuO films. The circuit frequency is tuned by changing distance X (capacity) between substrates. Potentiality of using substrates of lanthanum aluminate, neodymium gallate and strontium titanate for manufacture of single circuits was considered. Q-factor of the circuit amounted to 68000 at resonance frequency of 6.88 MHz [ru

  16. Excited baryon form factors at high Q2

    International Nuclear Information System (INIS)

    Paul Stoler; Gary Adams; Abdellah Ahmidouch; Chris Armstrong; K. Assamagan; Steven Avery; K. Baker; Peter Bosted; Volker Burkert; Jim Dunne; Tom Eden; Rolf Ent; V. Frolov; David Gaskell; P. Gueye; Wendy Hinton; Cynthia Keppel; Wooyoung Kim; Michael Klusman; Doug Koltenuk; David Mack; Richard Madey; David Meekins; Ralph Minehart; Joseph Mitchell; Hamlet Mkrtchyan; James Napolitano; Gabriel Niculescu; Ioana Niculescu; Mina Nozar; John Price; Paul Stoler; Vardan Tadevosyan; Liguang Tang; Michael Witkowski; Stephen Wood

    1998-01-01

    The role of resonance electroproduction at high Q 2 is discussed in the context of exclusive reactions, as well as the alternative theoretical models which are proposed to treat exclusive reactions in the few GeV 2 /c 2 region of momentum transfer. Jefferson Lab experiment 94-014, which measured the excitation of the Delta (1232) and S 11 (1535) via the reactions p(e,e ' p)pi 0 and p(e,e ' p)eta respectively at Q 2 ∼ 2.8 and 4 GeV 2 /c 2 is described, and the state of analysis reported

  17. High-Q Photonic-Crystal Cavities for Light Amplification and Lasing

    Science.gov (United States)

    2011-06-10

    Neoclassical Theory of Electric Charges", to appear in Discrete and Continuous Dynamical Systems, Vol. 27, Number 4, August 2010. - A. Figotin, I...dynamics of PDE", ICMS, Edinburgh, September, 2010 - A. Figotn and A. Babin, "Some Mathematical Problems in a Neoclassical Theory of Electric Charges...34, Weizmann Institute, Rehovot, Israel, August, 2010. - A. Figotn and A. Babin, "Some Mathematical Problems in a Neoclassical Theory of Electric

  18. Inversionless superradiance of an ensemble of three-level atoms in a high-Q cavity

    International Nuclear Information System (INIS)

    Zaitsev, A.I.; Ryzhov, I.V.; Trifonov, E.D.; Malyshev, V.A.

    1999-01-01

    We analyze the possibility of superradiance in an ensemble of three-level atoms in the absence of population inversion. We show that in the case of a Λ configuration of the active transitions this effect can occur for an initially coherent superposition of the states of the lower doublet. We also study how splitting of the lower levels influences this effect and discuss ways of creating low-frequency coherence

  19. Optical Microspherical Resonators for Biomedical Sensing

    Directory of Open Access Journals (Sweden)

    Giancarlo C. Righini

    2011-01-01

    Full Text Available Optical resonators play an ubiquitous role in modern optics. A particular class of optical resonators is constituted by spherical dielectric structures, where optical rays are total internal reflected. Due to minimal reflection losses and to potentially very low material absorption, these guided modes, known as whispering gallery modes, can confer the resonator an exceptionally high quality factor Q, leading to high energy density, narrow resonant-wavelength lines and a lengthy cavity ringdown. These attractive characteristics make these miniaturized optical resonators especially suited as laser cavities and resonant filters, but also as very sensitive sensors. First, a brief analysis is presented of the characteristics of microspherical resonators, of their fabrication methods, and of the light coupling techniques. Then, we attempt to overview some of the recent advances in the development of microspherical biosensors, underlining a number of important applications in the biomedical field.

  20. Cavity quantum electrodynamics

    International Nuclear Information System (INIS)

    Walther, Herbert; Varcoe, Benjamin T H; Englert, Berthold-Georg; Becker, Thomas

    2006-01-01

    This paper reviews the work on cavity quantum electrodynamics of free atoms. In recent years, cavity experiments have also been conducted on a variety of solid-state systems resulting in many interesting applications, of which microlasers, photon bandgap structures and quantum dot structures in cavities are outstanding examples. Although these phenomena and systems are very interesting, discussion is limited here to free atoms and mostly single atoms because these systems exhibit clean quantum phenomena and are not disturbed by a variety of other effects. At the centre of our review is the work on the one-atom maser, but we also give a survey of the entire field, using free atoms in order to show the large variety of problems dealt with. The cavity interaction can be separated into two main regimes: the weak coupling in cavity or cavity-like structures with low quality factors Q and the strong coupling when high-Q cavities are involved. The weak coupling leads to modification of spontaneous transitions and level shifts, whereas the strong coupling enables one to observe a periodic exchange of photons between atoms and the radiation field. In this case, atoms and photons are entangled, this being the basis for a variety of phenomena observed, some of them leading to interesting applications in quantum information processing. The cavity experiments with free atoms reached a new domain with the advent of experiments in the visible spectral region. A review on recent achievements in this area is also given

  1. Digitally Programmable High-Q Voltage Mode Universal Filter

    Directory of Open Access Journals (Sweden)

    D. Singh

    2013-12-01

    Full Text Available A new low-voltage low-power CMOS current feedback amplifier (CFA is presented in this paper. This is used to realize a novel digitally programmable CFA (DPCFA using transistor arrays and MOS switches. The proposed realizations nearly allow rail-to-rail swing capability at all the ports. Class-AB output stage ensures low power dissipation and high current drive capability. The proposed CFA/ DPCFA operates at supply voltage of ±0.75 V and exhibits bandwidth better than 95 MHz. An application of the DPCFA to realize a novel voltage mode high-Q digitally programmable universal filter (UF is given. Performances of all the proposed circuits are verified by PSPICE simulation using TSMC 0.25μm technology parameters.

  2. Two-body form factors at high Q2

    International Nuclear Information System (INIS)

    Gross, F.; Keister, B.D.

    1983-02-01

    The charge form factor of a scalar deuteron at high momentum transfer is examined in a model employing scalar nucleons and mesons. With an eye toward establishing consistency criteria for more realistic calculations, several aspects of the model are examined in detail: the role of nucleon and meson singularities in the one-loop impulse diagram, the role of positive-and negative-energy nucleons, and the relationship to time-ordered perturbation theory. It is found that at large Q 2 (1) the form factor is dominated by a term in which the spectator nucleon is on the mass shell, and (2) the meson singularity structure of the d-n-p vertex function is unimportant in determining the overall high-Q 2 behaviour of the form factor

  3. High Q, Miniaturized LCP-Based Passive Components

    KAUST Repository

    Shamim, Atif

    2014-10-16

    Various methods and systems are provided for high Q, miniaturized LCP-based passive components. In one embodiment, among others, a spiral inductor includes a center connection and a plurality of inductors formed on a liquid crystal polymer (LCP) layer, the plurality of inductors concentrically spiraling out from the center connection. In another embodiment, a vertically intertwined inductor includes first and second inductors including a first section disposed on a side of the LCP layer forming a fraction of a turn and a second section disposed on another side of the LCP layer. At least a portion of the first section of the first inductor is substantially aligned with at least a portion of the second section of the second inductor and at least a portion of the first section of the second inductor is substantially aligned with at least a portion of the second section of the first inductor.

  4. High Q, Miniaturized LCP-Based Passive Components

    KAUST Repository

    Shamim, Atif; Arabi, Eyad A.

    2014-01-01

    Various methods and systems are provided for high Q, miniaturized LCP-based passive components. In one embodiment, among others, a spiral inductor includes a center connection and a plurality of inductors formed on a liquid crystal polymer (LCP) layer, the plurality of inductors concentrically spiraling out from the center connection. In another embodiment, a vertically intertwined inductor includes first and second inductors including a first section disposed on a side of the LCP layer forming a fraction of a turn and a second section disposed on another side of the LCP layer. At least a portion of the first section of the first inductor is substantially aligned with at least a portion of the second section of the second inductor and at least a portion of the first section of the second inductor is substantially aligned with at least a portion of the second section of the first inductor.

  5. Metallic coating of microspheres

    International Nuclear Information System (INIS)

    Meyer, S.F.

    1980-01-01

    Extremely smooth, uniform metal coatings of micrometer thicknesses on microscopic glass spheres (microspheres) are often needed as targets for inertial confinement fusion (ICF) experiments. The first part of this paper reviews those methods used successfully to provide metal coated microspheres for ICF targets, including magnetron sputtering, electro- and electroless plating, and chemical vapor pyrolysis. The second part of this paper discusses some of the critical aspects of magnetron sputter coating of microspheres, including substrate requirements, the sticking of microspheres during coating (preventing a uniform coating), and the difficulties in growing the desired dense, smooth, uniform microstructure on continuously moving spherical substrates

  6. Enhancing the resonance stability of a high-Q micro/nanoresonator by an optical means

    Science.gov (United States)

    Sun, Xuan; Luo, Rui; Zhang, Xi-Cheng; Lin, Qiang

    2016-02-01

    High-quality optical resonators underlie many important applications ranging from optical frequency metrology, precision measurement, nonlinear/quantum photonics, to diverse sensing such as detecting single biomolecule, electromagnetic field, mechanical acceleration/rotation, among many others. All these applications rely essentially on the stability of optical resonances, which, however, is ultimately limited by the fundamental thermal fluctuations of the devices. The resulting thermo-refractive and thermo-elastic noises have been widely accepted for nearly two decades as the fundamental thermodynamic limit of an optical resonator, limiting its resonance uncertainty to a magnitude 10-12 at room temperature. Here we report a novel approach that is able to significantly improve the resonance stability of an optical resonator. We show that, in contrast to the common belief, the fundamental temperature fluctuations of a high-Q micro/nanoresonator can be suppressed remarkably by pure optical means without cooling the device temperature, which we term as temperature squeezing. An optical wave with only a fairly moderate power launched into the device is able to produce strong photothermal backaction that dramatically suppresses the spectral intensity of temperature fluctuations by five orders of magnitudes and squeezes the overall level (root-mean-square value) of temperature fluctuations by two orders of magnitude. The proposed approach is universally applicable to various micro/nanoresonator platforms and the optimal temperature squeezing can be achieved with an optical Q around 106-107 that is readily available in various current devices. The proposed photothermal temperature squeezing is expected to have profound impact on broad applications of high-Q cavities in sensing, metrology, and integrated nonlinear/quantum photonics.

  7. Microprocessor-controlled meter of high Q-values

    International Nuclear Information System (INIS)

    Bun'kov, S.N.; Konstantinov, V.I.; Masalov, V.L.; Sevrukova, L.M.; Tokarev, A.D.; Usiv, Yu.V.

    1990-01-01

    The paper describes the functional model of a high-precision microcomputer-controlled test facility for studying the electric and physical parameters of superconducting cavities. The basic unit of the test facility is high-stability retunable RF oscillator. It is designed following the scheme of the frequency phase tuning using standard equipment. The systematic error in measuring the loaded Q-value of reentrant cavities is not larger than 5%. A dedicated built-in microcomputer is used to control the measuring test facility and to make the commutations required. 2 refs.; 2 figs

  8. High-Q/V Monolithic Diamond Microdisks Fabricated with Quasi-isotropic Etching.

    Science.gov (United States)

    Khanaliloo, Behzad; Mitchell, Matthew; Hryciw, Aaron C; Barclay, Paul E

    2015-08-12

    Optical microcavities enhance light-matter interactions and are essential for many experiments in solid state quantum optics, optomechanics, and nonlinear optics. Single crystal diamond microcavities are particularly sought after for applications involving diamond quantum emitters, such as nitrogen vacancy centers, and for experiments that benefit from diamond's excellent optical and mechanical properties. Light-matter coupling rates in experiments involving microcavities typically scale with Q/V, where Q and V are the microcavity quality-factor and mode-volume, respectively. Here we demonstrate that microdisk whispering gallery mode cavities with high Q/V can be fabricated directly from bulk single crystal diamond. By using a quasi-isotropic oxygen plasma to etch along diamond crystal planes and undercut passivated diamond structures, we create monolithic diamond microdisks. Fiber taper based measurements show that these devices support TE- and TM-like optical modes with Q > 1.1 × 10(5) and V < 11(λ/n) (3) at a wavelength of 1.5 μm.

  9. Preventing Raman Lasing in High-Q WGM Resonators

    Science.gov (United States)

    Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry; Maleki, Lute

    2007-01-01

    A generic design has been conceived to suppress the Raman effect in whispering- gallery-mode (WGM) optical resonators that have high values of the resonance quality factor (Q). Although it is possible to exploit the Raman effect (even striving to maximize the Raman gain to obtain Raman lasing), the present innovation is intended to satisfy a need that arises in applications in which the Raman effect inhibits the realization of the full potential of WGM resonators as frequency-selection components. Heretofore, in such applications, it has been necessary to operate high-Q WGM resonators at unattractively low power levels to prevent Raman lasing. (The Raman-lasing thresholds of WGM optical resonators are very low and are approximately proportional to Q(sup -2)). Heretofore, two ways of preventing Raman lasting at high power levels have been known, but both entail significant disadvantages: A resonator can be designed so that the optical field is spread over a relatively large mode volume to bring the power density below the threshold. For any given combination of Q and power level, there is certain mode volume wherein Raman lasing does not start. Unfortunately, a resonator that has a large mode volume also has a high spectral density, which is undesirable in a typical photonic application. A resonator can be cooled to the temperature of liquid helium, where the Raman spectrum is narrower and, therefore, the Raman gain is lower. However, liquid-helium cooling is inconvenient. The present design overcomes these disadvantages, making it possible to operate a low-spectral-density (even a single-mode) WGM resonator at a relatively high power level at room temperature, without risk of Raman lasing.

  10. Thermal Loss of High-Q Antennas in Time Domain vs. Frequency Domain Solver

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Pedersen, Gert Frølund

    2014-01-01

    High-Q structures pose great challenges to their loss simulations in Time Domain Solvers (TDS). Therefore, in this work the thermal loss of high-Q antennas is calculated both in TDS and Frequency Domain Solver (FDS), which are then compared with each other and with the actual measurements....... The thermal loss calculation in FDS is shown to be more accurate for high-Q antennas....

  11. Coupling Ideality of Integrated Planar High-Q Microresonators

    Science.gov (United States)

    Pfeiffer, Martin H. P.; Liu, Junqiu; Geiselmann, Michael; Kippenberg, Tobias J.

    2017-02-01

    Chip-scale optical microresonators with integrated planar optical waveguides are useful building blocks for linear, nonlinear, and quantum-optical photonic devices alike. Loss reduction through improving fabrication processes results in several integrated microresonator platforms attaining quality (Q ) factors of several millions. Beyond the improvement of the quality factor, the ability to operate the microresonator with high coupling ideality in the overcoupled regime is of central importance. In this regime, the dominant source of loss constitutes the coupling to a single desired output channel, which is particularly important not only for quantum-optical applications such as the generation of squeezed light and correlated photon pairs but also for linear and nonlinear photonics. However, to date, the coupling ideality in integrated photonic microresonators is not well understood, in particular, design-dependent losses and their impact on the regime of high ideality. Here we investigate design-dependent parasitic losses described by the coupling ideality of the commonly employed microresonator design consisting of a microring-resonator waveguide side coupled to a straight bus waveguide, a system which is not properly described by the conventional input-output theory of open systems due to the presence of higher-order modes. By systematic characterization of multimode high-Q silicon nitride microresonator devices, we show that this design can suffer from low coupling ideality. By performing 3D simulations, we identify the coupling to higher-order bus waveguide modes as the dominant origin of parasitic losses which lead to the low coupling ideality. Using suitably designed bus waveguides, parasitic losses are mitigated with a nearly unity ideality and strong overcoupling (i.e., a ratio of external coupling to internal resonator loss rate >9 ) are demonstrated. Moreover, we find that different resonator modes can exchange power through the coupler, which, therefore

  12. Glass microspheres for brachytherapy

    International Nuclear Information System (INIS)

    Prado, Miguel O.; Prastalo, Simon; Blaumann, Herman; Longhino, Juan M.; Repetto Llamazares, A.H.V.

    2007-01-01

    We developed the capacity to produce glass microspheres containing in their structure one or more radioactive isotopes useful for brachytherapy. We studied the various facts related with their production: (Rare earth) alumino silicate glass making, glass characterization, microspheres production, nuclear activation through (n,γ) nuclear reactions, mechanical characterization before and after irradiation. Corrosion tests in simulated human plasma and mechanical properties characterization were done before and after irradiation. (author) [es

  13. Method for sizing hollow microspheres

    Science.gov (United States)

    Farnum, E.H.; Fries, R.J.

    1975-10-29

    Hollow Microspheres may be effectively sized by placing them beneath a screen stack completely immersed in an ultrasonic bath containing a liquid having a density at which the microspheres float and ultrasonically agitating the bath.

  14. Ceramic microspheres for cementing applications

    NARCIS (Netherlands)

    2011-01-01

    A method and apparatus for manufacturing ceramic microspheres from industrial slag. The microspheres have a particle size of about 38 microns to about 150 microns. The microspheres are used to create a cement slurry having a density of at least about 11 lbs/g. The resultant cement slurry may then be

  15. Ceramic microspheres for cementing applications

    NARCIS (Netherlands)

    2010-01-01

    A method and apparatus for manufacturing ceramic microspheres from industrial slag. The microspheres have a particle size of about 38 microns to about 150 microns. The microspheres are used to create a cement slurry having a density of at least about 11 lbs/g. The resultant cement slurry may then be

  16. Ceramic microspheres for cementing applications

    NARCIS (Netherlands)

    2012-01-01

    A method and apparatus for manufacturing ceramic microspheres from industrial slag. The microspheres have a particle size of about 38 microns to about 150 microns. The microspheres are used to create a cement slurry having a density of at least about 11 lbs/g. The resultant cement slurry may then be

  17. Optical transport and statistics of radiative losses in disordered chains of microspheres

    International Nuclear Information System (INIS)

    Deng Chaosheng; Xu Hui; Deych, Lev

    2010-01-01

    Optical transport in a one-dimensional chain of microspherical resonators with size disorder is studied in the spectral range of high-Q whispering gallery modes. An ab initio approach is used to develop a theoretical framework for analysis of steady-state transport parameters with main emphasis on properly defined radiative loss coefficient. Probability distribution and scaling properties of the latter are established and explained.

  18. Synthesis of V2O5 microspheres by spray pyrolysis as cathode material for supercapacitors

    Science.gov (United States)

    Yin, Zhendong; Xu, Jie; Ge, Yali; Jiang, Qiaoya; Zhang, Yaling; Yang, Yawei; Sun, Yuping; Hou, Siyu; Shang, Yuanyuan; Zhang, Yingjiu

    2018-03-01

    Vanadium oxide (V2O5) microspheres have attracted considerable attention in the energy field due to their unique properties such as high stability and electrochemical activity. Here, massive V2O5 microspheres with smooth surface, hollow cavity and uniform particle sizes (0.4–1.5 μm), were synthesized by a facile spray pyrolysis process. Post-treatment at predefined temperatures effectively turned the microsphere shell into stacked nanorods with widths of 100 nm and lengths of 500 nm when processed at 500 °C for 3 h under nitrogen atmosphere, with enhanced crystallinity. When applied as cathode materials for supercapacitors, the post-treated V2O5 microspheres at 500 °C exhibited improved specific capacitance and longer discharge time. This is an effective method to manufacture massive V2O5 microspheres with tailored structure and potential applications in high-performance energy storage materials.

  19. Preparation of alumina microspheres

    International Nuclear Information System (INIS)

    Santos, W.R. dos; Abrao, A.

    1980-01-01

    Inorganic exchangers are widely used for adsorption and column partition chromatography. The main difficulty of using commercial alumina (in powder) for column chromatography is related to its packing, and the operations through the column become diffcult and time-consuming; also it turns to be virtually impossible to use large dimension columns. In order to eliminate these problems, a process for the preparation of alumina micro-spheres was developed as an adaptation of a similar process used to prepare nuclear fuel microspheres (UO 2 , ThO 2 ). The flowsheet of this process is presented together with the analytical results of sphericity after calcination, granulometry, density and characterization by X-ray diffractometry. Solubility tests showed that the so-prepared microspheres are well resistant to strong acids and bases; retention tests showed their efficiency, mainly to copper. (C.L.B.) [pt

  20. Silicon Microspheres Photonics

    International Nuclear Information System (INIS)

    Serpenguzel, A.

    2008-01-01

    Electrophotonic integrated circuits (EPICs), or alternatively, optoelectronic integrated circuit (OEICs) are the natural evolution of the microelectronic integrated circuit (IC) with the addition of photonic capabilities. Traditionally, the IC industry has been based on group IV silicon, whereas the photonics industry on group III-V semiconductors. However, silicon based photonic microdevices have been making strands in siliconizing photonics. Silicon microspheres with their high quality factor whispering gallery modes (WGMs), are ideal candidates for wavelength division multiplexing (WDM) applications in the standard near-infrared communication bands. In this work, we will discuss the possibility of using silicon microspheres for photonics applications in the near-infrared

  1. Ultimate Gradient Limitation in Niobium Superconducting Accelerating Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Checchin, Mattia [Illinois Inst. of Technology, Chicago, IL (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Grassellino, Anna [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Martinello, Martina [Illinois Inst. of Technology, Chicago, IL (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Posen, Sam [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Romanenko, Alexander [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Zasadzinski, John [Illinois Inst. of Technology, Chicago, IL (United States)

    2016-06-01

    The present study is addressed to the theoretical description of the ultimate gradient limitation in SRF cavities. Our intent is to exploit experimental data to confirm models which provide feed-backs on how to improve the current state-of-art. New theoretical insight on the cavities limiting factor can be suitable to improve the quench field of N-doped cavities, and therefore to take advantage of high Q0 at high gradients.

  2. 188Re-microspheres of albumin - the potential preparation for radiotherapy

    International Nuclear Information System (INIS)

    Dyomin, D.N.; Petriev, V.M.

    2000-01-01

    In this paper author describe preparation the albumin microspheres labelled with rhenium-188. We undertake an attempt to develop kits to the generator of rhenium-188 on the basis of albumin microspheres for radiotherapy of both oncological and non-oncological diseases. Microspheres, rhenium-188 with sizes 1 0-20 micron for treatment of rheumatoid arthritis (damage of large and intermediate joints), intraperitoneal administration and intrapleural administration at metastases covering a cavity. Microspheres, Re-188 with sizes 40-60 micron for treatment of disseminated kidney cancer (intraarterial, selectively), intratumoral administration to damaged nodules less than 2-3 cm. Microspheres, Re-188 with sizes 80-100 micron for large neoplasms and metastases of liver (intraarterial, selectively), intratumoral administration to damaged nodules with sizes over 3 cm. Preparation of albumin microspheres is carried out by thermal denaturation of protein in vegetable oil. Microspheres are obtained with the necessary range of sizes by ultrasonic fractionation. At our laboratory the method of preparation of albumin microspheres with any sizes of particles (from 5 -10 up to 800 -1000 microns) has been developed. (authors)

  3. Synthesis of magnetic polymeric microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Gervald, A Yu; Gritskova, Inessa A; Prokopov, Nikolai I [M.V. Lomonosov Moscow State Academy of Fine Chemical Technology, Moscow (Russian Federation)

    2010-05-13

    The key types of magnetic polymeric microspheres are considered. Methods of synthesis of different types of magnetic nanoparticles and of preparation of stable magnetic fluids on their basis are outlined. The overview of the methods for the manufacture of magnetic polymeric microspheres is presented. The effect of the synthesis conditions on the characteristics of magnetic polymeric microspheres such as the diameter and the particle size distribution and the content of magnetic material is discussed by particular examples. The application fields of magnetic polymeric microspheres are briefly surveyed.

  4. Synthesis of magnetic polymeric microspheres

    International Nuclear Information System (INIS)

    Gervald, A Yu; Gritskova, Inessa A; Prokopov, Nikolai I

    2010-01-01

    The key types of magnetic polymeric microspheres are considered. Methods of synthesis of different types of magnetic nanoparticles and of preparation of stable magnetic fluids on their basis are outlined. The overview of the methods for the manufacture of magnetic polymeric microspheres is presented. The effect of the synthesis conditions on the characteristics of magnetic polymeric microspheres such as the diameter and the particle size distribution and the content of magnetic material is discussed by particular examples. The application fields of magnetic polymeric microspheres are briefly surveyed.

  5. Trapping of a microsphere pendulum resonator in an optical potential

    International Nuclear Information System (INIS)

    Ward, J. M.; Wu, Y.; Nic Chormaic, S.; Minogin, V. G.

    2009-01-01

    We propose a method to spatially confine or corral the movements of a micropendulum via the optical forces produced by two simultaneously excited optical modes of a photonic molecule comprising two microspherical cavities. We discuss how the cavity-enhanced optical force generated in the photonic molecule can create an optomechanical potential of about 10 eV deep and 30 pm wide, which can be used to trap the pendulum at any given equilibrium position by a simple choice of laser frequencies. This result presents opportunities for very precise all-optical self-alignment of microsystems.

  6. Dental cavities

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001055.htm Dental cavities To use the sharing features on this page, please enable JavaScript. Dental cavities are holes (or structural damage) in the ...

  7. Nonlinear optical oscillation dynamics in high-Q lithium niobate microresonators.

    Science.gov (United States)

    Sun, Xuan; Liang, Hanxiao; Luo, Rui; Jiang, Wei C; Zhang, Xi-Cheng; Lin, Qiang

    2017-06-12

    Recent advance of lithium niobate microphotonic devices enables the exploration of intriguing nonlinear optical effects. We show complex nonlinear oscillation dynamics in high-Q lithium niobate microresonators that results from unique competition between the thermo-optic nonlinearity and the photorefractive effect, distinctive to other device systems and mechanisms ever reported. The observed phenomena are well described by our theory. This exploration helps understand the nonlinear optical behavior of high-Q lithium niobate microphotonic devices which would be crucial for future application of on-chip nonlinear lithium niobate photonics.

  8. Preparation of hollow hydroxyapatite microspheres by the conversion of borate glass at near room temperature

    International Nuclear Information System (INIS)

    Yao, Aihua; Ai, Fanrong; Liu, Xin; Wang, Deping; Huang, Wenhai; Xu, Wei

    2010-01-01

    Hollow hydroxyapatite microspheres, consisting of a hollow core and a porous shell, were prepared by converting Li 2 O-CaO-B 2 O 3 glass microspheres in dilute phosphate solution at 37 o C. The results confirmed that Li 2 O-CaO-B 2 O 3 glass was transformed to hydroxyapatite without changing the external shape and dimension of the original glass object. Scanning electron microscopy images showed the shell wall of the microsphere was built from hydroxyapatite particles, and these particles spontaneously align with one another to form a porous sphere with an interior cavity. Increase in phosphate concentration resulted in an increase in the reaction rate, which in turn had an effect on shell wall structure of the hollow hydroxyapatite microsphere. For the Li 2 O-CaO-B 2 O 3 glass microspheres reacted in low-concentration K 2 HPO 4 solution, lower reaction rate and a multilayered microstructure were observed. On the other hand, the glass microspheres reacted in higher phosphate solution converted more rapidly and produced a single hydroxyapatite layer. Furthermore, the mechanism of forming hydroxyapatite hollow microsphere was described.

  9. Benchmarking state-of-the-art numerical simulation techniques for analyzing large photonic crystal membrane line defect cavities

    DEFF Research Database (Denmark)

    Gregersen, Niels; de Lasson, Jakob Rosenkrantz; Frandsen, Lars Hagedorn

    2018-01-01

    In this work, we perform numerical studies of two photonic crystal membrane microcavities, a short line-defect L5 cavity with relatively low quality (Q) factor and a longer L9 cavity with high Q. We compute the cavity Q factor and the resonance wavelength λ of the fundamental M1 mode in the two...

  10. Synthesis of Hollow CdS-TiO2 Microspheres with Enhanced Visible-Light Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Yuning Huo

    2012-01-01

    Full Text Available CdS-TiO2 composite photocatalyst in the shape of hollow microsphere was successfully synthesized via the hard-template preparation with polystyrene microspheres followed by ion-exchange approach. The hollow CdS-TiO2 microspheres significantly extended the light adsorption into visible light region, comparing to TiO2 microspheres. It led to much higher photocatalytic activities of hollow CdS-TiO2 microspheres than that of TiO2 during the photodegradation of rhodamine B under visible light irradiations. Furthermore, the well-remained hollow structure could achieve light multireflection within the interior cavities and the separation of photo-induced electrons and holes is efficient in CdS-TiO2, which were facilitated to improving the photoactivity.

  11. Development and gamma-scintigraphy study of Hibiscus rosasinensis polysaccharide-based microspheres for nasal drug delivery.

    Science.gov (United States)

    Sharma, Nitin; Tyagi, Shanu; Gupta, Satish Kumar; Kulkarni, Giriraj Thirupathirao; Bhatnagar, Aseem; Kumar, Neeraj

    2016-11-01

    This work describes the application of natural plant polysaccharide as pharmaceutical mucoadhesive excipients in delivery systems to reduce the clearance rate through nasal cavity. Novel natural polysaccharide (Hibiscus rosasinensis)-based mucoadhesive microspheres were prepared by using emulsion crosslinking method for the delivery of rizatriptan benzoate (RB) through nasal route. Mucoadhesive microspheres were characterized for different parameters and nasal clearance of technetium-99m ((99m)Tc)-radiolabeled microspheres was determined by using gamma-scintigraphy. Their Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies showed that the drug was stable during preparation of microspheres. Aerodynamic diameter of microspheres was in the range 13.23 ± 1.83-33.57 ± 3.69 µm. Change in drug and polysaccharide ratio influenced the mucoadhesion, encapsulation efficiency and in-vitro release property. Scintigraphs taken at regular interval indicate that control solution was cleared rapidly from nasal cavity, whereas microspheres showed slower clearance (p < 0.005) with half-life of 160 min. Natural polysaccharide-based microspheres achieved extended residence by minimizing effect of mucociliary clearance with opportunity of sustained delivery for longer duration.

  12. Acoustic trapping in bubble-bounded micro-cavities

    Science.gov (United States)

    O'Mahoney, P.; McDougall, C.; Glynne-Jones, P.; MacDonald, M. P.

    2016-12-01

    We present a method for controllably producing longitudinal acoustic trapping sites inside microfluidic channels. Air bubbles are injected into a micro-capillary to create bubble-bounded `micro-cavities'. A cavity mode is formed that shows controlled longitudinal acoustic trapping between the two air/water interfaces along with the levitation to the centre of the channel that one would expect from a lower order lateral mode. 7 μm and 10 μm microspheres are trapped at the discrete acoustic trapping sites in these micro-cavities.We show this for several lengths of micro-cavity.

  13. Review: microspheres for radioembolization therapy

    International Nuclear Information System (INIS)

    Zhao Mingqiang; Xu Shuhe

    2007-12-01

    Radioembolization of liver cancer has been proven to be an effective therapy in nuclear medicine. The yttrium-90 glass microspheres has been used to treat both primary and metastatic liver tumors in clinic which shown encouraging results. The preparation, stability, degradation and application for medical purpose of radioactive microspheres are reviewed. At first, the theory of radioem- bolization treating cancer is discussed; and then three major radiolabled micro- sphere materials are expounded: viz. glass, resin-based and polymer-based; Future improvements in the preparation and use of radioactive microspheres are prospected at last. (authors)

  14. Review: microspheres for radioembolization therapy

    Energy Technology Data Exchange (ETDEWEB)

    Mingqiang, Zhao; Shuhe, Xu [China Inst. of Atomic Energy, Beijing (China)

    2007-12-15

    Radioembolization of liver cancer has been proven to be an effective therapy in nuclear medicine. The yttrium-90 glass microspheres has been used to treat both primary and metastatic liver tumors in clinic which shown encouraging results. The preparation, stability, degradation and application for medical purpose of radioactive microspheres are reviewed. At first, the theory of radioem- bolization treating cancer is discussed; and then three major radiolabled micro- sphere materials are expounded: viz. glass, resin-based and polymer-based; Future improvements in the preparation and use of radioactive microspheres are prospected at last. (authors)

  15. Coherent Dynamics of Quantum Dots in Photonic-Crystal Cavities

    DEFF Research Database (Denmark)

    Madsen, Kristian Høeg

    deviations. Similar measurements on a quantum dot in a photonic-crystal cavity sow a Rabi splitting on resonance, while time-resolved measurements prove that the system is in the weak coupling regime. Whle tuning the quantum dot through resonance of the high-Q mode we observe a strong and surprisingly...

  16. Cancelling disorder-induced localization in nanophotonic cavity arrays

    NARCIS (Netherlands)

    Sokolov, Sergei; Lian, Jin; Yuce, E.; Combrie, S.; de Rossi, A.; Mosk, Allard

    2016-01-01

    Weakly coupled high-Q nanophotonic cavities are building blocks of slow-light waveguides and other nanophotonic devices. Their functionality critically depends on tuning as resonance frequencies should stay within the bandwidth of the device. Unavoidable disorder leads to random frequency shifts

  17. STIR-Physics: Cold Atoms and Nanocrystals in Tapered Nanofiber and High-Q Resonator Potentials

    Science.gov (United States)

    2016-11-02

    STIR- Physics : Cold Atoms and Nanocrystals in Tapered Nanofiber and High-Q Resonator Potentials We worked on a tapered fiber in cold atomic cloud...reviewed journals: Number of Papers published in non peer-reviewed journals: Final Report: STIR- Physics : Cold Atoms and Nanocrystals in Tapered Nanofiber...other than abstracts): Number of Peer-Reviewed Conference Proceeding publications (other than abstracts): Books Number of Manuscripts: 0.00Number of

  18. A new method of distinguishing models of the high-Q2 events at HERA

    International Nuclear Information System (INIS)

    Cao, Z.; He, X.G.; McKellar, B.

    1997-07-01

    A new method is proposed to distinguish models for the high Q 2 e + p → e + X anomaly at HERA by looking at a new observable which is insensitive to parton distribution function (PDF), but sensitive to new physics. Three models have been considered: modification of PDF's, new physics due to s-channel production of new particle and new physics due to contact interactions. Using this new method it is possible to distinguish different models with increased luminosity

  19. Bandwidth-limited control and ringdown suppression in high-Q resonators.

    Science.gov (United States)

    Borneman, Troy W; Cory, David G

    2012-12-01

    We describe how the transient behavior of a tuned and matched resonator circuit and a ringdown suppression pulse may be integrated into an optimal control theory (OCT) pulse-design algorithm to derive control sequences with limited ringdown that perform a desired quantum operation in the presence of resonator distortions of the ideal waveform. Inclusion of ringdown suppression in numerical pulse optimizations significantly reduces spectrometer deadtime when using high quality factor (high-Q) resonators, leading to increased signal-to-noise ratio (SNR) and sensitivity of inductive measurements. To demonstrate the method, we experimentally measure the free-induction decay of an inhomogeneously broadened solid-state free radical spin system at high Q. The measurement is enabled by using a numerically optimized bandwidth-limited OCT pulse, including ringdown suppression, robust to variations in static and microwave field strengths. We also discuss the applications of pulse design in high-Q resonators to universal control of anisotropic-hyperfine coupled electron-nuclear spin systems via electron-only modulation even when the bandwidth of the resonator is significantly smaller than the hyperfine coupling strength. These results demonstrate how limitations imposed by linear response theory may be vastly exceeded when using a sufficiently accurate system model to optimize pulses of high complexity. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Quantum gate for Q switching in monolithic photonic-band-gap cavities containing two-level atoms

    International Nuclear Information System (INIS)

    Greentree, Andrew D.; Prawer, Steven; Hollenberg, Lloyd C. L.; Salzman, J.

    2006-01-01

    Photonic-band-gap cavities are prime solid-state systems to investigate light-matter interactions in the strong coupling regime. However, as the cavity is defined by the geometry of the periodic dielectric pattern, cavity control in a monolithic structure can be problematic. Thus, either the state coherence is limited by the read-out channel, or in a high-Q cavity, it is nearly decoupled from the external world, making measurement of the state extremely challenging. We present here a method for ameliorating these difficulties by using a coupled cavity arrangement, where one cavity acts as a switch for the other cavity, tuned by control of the atomic transition

  1. Atom-Photon Coupling from Nitrogen-vacancy Centres Embedded in Tellurite Microspheres

    Science.gov (United States)

    Ruan, Yinlan; Gibson, Brant C.; Lau, Desmond W. M.; Greentree, Andrew D.; Ji, Hong; Ebendorff-Heidepriem, Heike; Johnson, Brett C.; Ohshima, Takeshi; Monro, Tanya M.

    2015-06-01

    We have developed a technique for creating high quality tellurite microspheres with embedded nanodiamonds (NDs) containing nitrogen-vacancy (NV) centres. This hybrid method allows fluorescence of the NVs in the NDs to be directly, rather than evanescently, coupled to the whispering gallery modes of the tellurite microspheres at room temperature. As a demonstration of its sensing potential, shifting of the resonance peaks is also demonstrated by coating a sphere surface with a liquid layer. This new approach is a robust way of creating cavities for use in quantum and sensing applications.

  2. accelerating cavity

    CERN Multimedia

    On the inside of the cavity there is a layer of niobium. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment.

  3. Baking effect on Niobium superconducting RF cavities and its physical interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Saito, K. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan); Kneisel, P. [Thomas Jefferson Accelerator Facility, VA, (United States)

    2000-07-01

    Recently a very surprising phenomenon has been discovered at JLab and Saclay with chemically polished niobium cavities, which the baking during vacuum evacuation has benefits to improve the cavity performance: high Q and high gradient. We have confirmed the same effect on the electropolished niobium cavities. We have analyzed the temperature dependence of the surface resistance in order to understand this effect in the frame or BCS theory. In this paper these results will be presented. (author)

  4. Lasing in dye-doped high-Q conical polymeric microcavities

    DEFF Research Database (Denmark)

    Grossmann, Tobias; Schleede, Simone; Hauser, Mario

    2011-01-01

    in the quasistationary pumping regime. Lasing wavelengths are detected in the visible wavelength region around 600 nm. Finite element simulations indicate that lasing occurs in fundamental TE/TM cavity modes, as these modes have - in comparison to higher order cavity modes - the smallest mode volume and the largest...

  5. Gastroretentive Floating Microspheres of Silymarin: Preparation and ...

    African Journals Online (AJOL)

    Methods: Cellulose microspheres – formulated with hydroxylpropyl methylcellulose (HPMC) and ethyl cellulose (EC) – and Eudragit microspheres – formulated with Eudragit® S 100 (ES) and Eudragit® RL (ERL) - were prepared by an emulsion-solvent evaporation method. The floating microspheres were evaluated for flow ...

  6. radiofrequency cavity

    CERN Multimedia

    1988-01-01

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  7. Aspects of High-Q Tunable Antennas and Their Deployment for 4G Mobile Communications

    DEFF Research Database (Denmark)

    Bahramzy, Pevand; Jagielski, Ole; Svendsen, Simon

    2016-01-01

    Tunable antennas are very promising for future generations of mobile communications, where broad frequency coverage will be required increasingly. This work describes the design of small high-Quality factor (Q) tunable antennas based on Micro-Electro-Mechanical Systems (MEMS), which are capable...... of operation in the frequency ranges 600 - 960 MHz and 1710 - 2690 MHz. Some aspects of high-Q tunable antennas are investigated through experimental measurements and the result are presented. Results show that more than -30 dB of isolation can be achieved between the Transmit (Tx) and Receive (Rx) antennas...

  8. Charged Particle Production in High Q2 Deep-Inelastic Scattering at HERA

    CERN Document Server

    Aaron, F.D.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M.E.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martisikova, M.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A.J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smiljanic, Ivan; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Tran, T.H.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2007-01-01

    The average charged track multiplicity and the normalised distribution of the scaled momentum, $\\xp$, of charged final state hadrons are measured in deep-inelastic $\\ep$ scattering at high $Q^2$ in the Breit frame of reference. The analysis covers the range of photon virtuality $100 < Q^2 < 20 000 \\GeV^{2}$. Compared with previous results presented by HERA experiments this analysis has a significantly higher statistical precision and extends the phase space to higher $Q^{2}$ and to the full range of $\\xp$. The results are compared with $e^+e^-$ annihilation data and with various calculations based on perturbative QCD using different models of the hadronisation process.

  9. Charged particle production in high Q deep-inelastic scattering at HERA

    Science.gov (United States)

    H1 Collaboration; Aaron, F. D.; Aktas, A.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Avila, K. B. Cantun; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J. G.; Coughlan, J. A.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; de Roeck, A.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M. E.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A. J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Toll, T.; Tomasz, F.; Tran, T. H.; Traynor, D.; Trinh, T. N.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Trevino, A. Vargas; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2007-10-01

    The average charged track multiplicity and the normalised distribution of the scaled momentum, x, of charged final state hadrons are measured in deep-inelastic ep scattering at high Q in the Breit frame of reference. The analysis covers the range of photon virtuality 100

  10. Charged particle production in high Q2 deep-inelastic scattering at HERA

    Science.gov (United States)

    Aaron, F. D.; Aktas, A.; Alexa, C.; Andreev, V.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Avila, K. B. Cantun; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J. G.; Coughlan, J. A.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Daum, K.; Deak, M.; de Boer, Y.; Delcourt, B.; Del Degan, M.; Delvax, J.; De Roeck, A.; De Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eliseev, A.; Elsen, E.; Essenov, S.; Falkiewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Finke, L.; Fleischer, M.; Fomenko, A.; Franke, G.; Frisson, T.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Jacquet, M.; Janssen, M. E.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, A. W.; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Li, G.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, H.; Meyer, J.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nowak, G.; Nowak, K.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; Polifka, R.; Povh, B.; Preda, T.; Prideaux, P.; Radescu, V.; Rahmat, A. J.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salek, D.; Salvaire, F.; Sankey, D. P. C.; Sauter, M.; Sauvan, E.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stiewe, J.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Toll, T.; Tomasz, F.; Tran, T. H.; Traynor, D.; Trinh, T. N.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Utkin, D.; Valkárová, A.; Vallée, C.; Van Mechelen, P.; Trevino, A. Vargas; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.; H1 Collaboration

    2007-10-01

    The average charged track multiplicity and the normalised distribution of the scaled momentum, xp, of charged final state hadrons are measured in deep-inelastic ep scattering at high Q2 in the Breit frame of reference. The analysis covers the range of photon virtuality 100

  11. High Q-factor metasurfaces based on miniaturized asymmetric single split resonators

    Science.gov (United States)

    Al-Naib, Ibraheem A. I.; Jansen, Christian; Koch, Martin

    2009-04-01

    We introduce asymmetric single split rectangular resonators as bandstop metasurfaces, which exhibit very high Q-factors in combination with low passband losses and a small electrical footprint. The effect of the degree of asymmetry on the frequency response is thoroughly studied. Furthermore, complementary structures, which feature a bandpass behavior, were derived by applying Babinet's principle and investigated with regards to their transmission characteristics. In future, asymmetric single split rectangular resonators could provide efficient unit cells for frequency selective surface devices, such as thin-film sensors or high performance filters.

  12. Hydroforming of Tesla Cavities at Desy

    International Nuclear Information System (INIS)

    Singer, W.; Kaiser, H.; Singer, X.; Gonin, I.; Zhelezov, I.; Khabibullin, T.; Kneisel, P.; Saito, K.

    2000-01-01

    Since several years the development of seamless niobium cavity fabrication by hydro forming is being pursued at DESY. This technique offers the possibility of lower cost of fabrication and perhaps better rf performance of the cavities because of the elimination of electron-beam welds, which in the standard fabrication technique have sometimes lead to inferior cavity performance due to defects. Several single cell 1300 MHz cavities have been formed from high purity seamless niobium tubes, which are under computer control expanded with internal pressure while simultaneously being swaged axially. The seamless tubes have been made by either back extrusion and flow forming or by spinning or deep drawing. Standard surface treatment techniques such as high temperature post purification, buffered chemical polishing (BCP), electropolishing (EP) and high pressure ultra pure water rinsing (HPR) have been applied to these cavities. The cavities exhibited high Q - values of 2 x 10 10 at 2K and residual resistances as low as 3 n(Omega) after the removal of a surface layer of app. 100 (micro)m by BCP. Surprisingly, even at high gradients up to the maximum measured values of E acc ∼ 33 MV/m the Q-value did not decrease in the absence of field emission as often observed. After electropolishing of additional 100 (micro)m one of the cavities reached an accelerating gradient of E acc (ge) 42 MV/m

  13. Temperature influence in crystallinity of polymer microspheres

    International Nuclear Information System (INIS)

    Rezende, Cristiane de P.; Novack, Katia M.

    2011-01-01

    Drug delivery technology is evolving through the creation of new techniques of drug delivery effectively. The new methods used in drugs administration are based in microencapsulation process. Microsphere encapsulation modifies drug delivery bringing benefits and efficiency. In this work has been evaluated the influence of temperature in microspheres preparation. Microspheres were obtained by PMMA-co-PEG (COP) copolymer with indomethacin inserted in polymer matrix. Samples were characterized by SEM, DSC and XRD. SEM micrographs confirmed the formation of different sizes of microspheres and it was verified that higher temperatures make more crystalline microspheres. (author)

  14. Modeling and Analysis of a Closed-Loop System for High-Q MEMS Accelerometer Sensor

    Directory of Open Access Journals (Sweden)

    Wang Yalin

    2018-01-01

    Full Text Available High-Q sensing element is desirable for high performance while makes the loop control a great challenge. This paper presents a closed-loop system for high-Q capacitive MEMS accelerometer which has achieved loop control effectively. The proportional-derivative(PDcontrol is developed in the system to improve the system stability. In addition, pulse width modulation (PWM electrostatic force feedback is designed in the loop to overcome the nonlinearity. Furthermore, a sigma-delta (ΣΔ modulator with noise shaping is built to realize digital output. System model is built in Matlab/Simulink. The simulation results indicate that equivalent Q value is reduced to 1.5 to ensure stability and responsiveness of the system. The effective number of bits of system output is 14.7 bits. The system nonlinearity is less than 5‰. The equivalent linear model including main noise factors is built, and then a complete theory of noise and linearity analysis is established to contribute to common MEMS accelerometer research.

  15. A SRF niobium cylindrical cavity with a large silicon nitride niobium-coated membrane as one end-wall

    Science.gov (United States)

    Martinez, Luis; Castelli, Alessandro; Pate, Jacob; Thompson, Johnathon; Delmas, William; Sharping, Jay; Chiao, Raymond; Chiao Team; Sharping Team

    The development of large silicon nitride membranes and niobium film deposition techniques motivate new architectures in opto-mechanics and microwave devices that can exploit the extremely high Q's obtainable with superconducting radio frequency (SRF) niobium cavities. We present a X-band SRF cylindrical cavity-membrane system in which one end-wall of the cavity is replaced by a niobium coated centimeter-sized silicon nitride membrane. We report moderately high Q factors above 10 million. Experimental results characterizing the system and potential future applications for such schemes in microwave devices and optomechanics are discussed.

  16. Two-Phase Diffusion Technique for the Preparation of Ultramacroporous/Mesoporous Silica Microspheres via Interface Hydrolysis, Diffusion, and Gelation of TEOS.

    Science.gov (United States)

    Ju, Minhua; Li, Yupeng; Yu, Liang; Wang, Chongqing; Zhang, Lixiong

    2018-02-06

    Honeycombed hierarchical ultramacroporous/mesoporous silica microspheres were prepared via the hydrolysis of TEOS in the oil-water interface, with subsequent diffusion and gelation in the acidic water-phase microdroplets with the assistance of a simple homemade microdevice. The diffusion of furfuryl alcohol (FA) also happened at a relatively high rate during the hydrolysis and diffusion of TEOS. Therefore, plenty of FA will be inside of the water microdroplets and form a decent number of polyfurfuryl alcohol (PFA) microparticles, thereby obtaining honeycombed hierarchical porosity silica microspheres with abundant ultramacroporous cavities and mesopores after calcination. It was found that the concentration of FA, residence time, and reaction temperature have significant effects on the porosity and pore size due to the influence on the diffusion rate and amount of FA in water-phase microdroplets. The honeycombed silica microspheres have obvious microscopic visible ultramacroporous cavities with the submicrometer cavity diameter as high as 85% porosity based on the rough overall volume of microsphere. N 2 adsorption-desorption isotherms show that the honeycombed hierarchical porosity silica microspheres have a high surface area of 602 m 2 g -1 , a mesopore volume of 0.77 cm 3 /g, and a mesopore porosity of 99.6% based on the total pore volume of N 2 adsorption-desorption. On the basis of the experiment results, a rational formation process of the honeycombed hierarchical porosity silica microspheres was deduced.

  17. Observation of Stable Low Surface Resistance in Large-Grain Niobium SRF Cavities

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Rongli [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Huang, Shichun [Institute of Modern Physics (IMP)/Chinese Academy of Sciences (CAS), Lanzhou (China)

    2016-05-01

    Low surface resistance, or high unloaded quality factor (Q0), superconducting radio frequency (SRF) cavities are being pursued actively nowadays as their application in large-scale CW SRF accelerators can save capital and operational cost in cryogenics. There are different options in realization of such cavities. One of them is the large-grain (LG) niobium cavity. In this contribution, we present new experimental results in evaluation of LG niobium cavities cooled down in the presence of an external magnetic field. High Q0 values are achieved even with an ambient magnetic field of up to 100 mG. More over, it is observed that these high Q0 values are super-robust against repeated quench, literally not affected at all after the cavity being deliberately quenched for hundreds of times in the presence of an ambient magnetic field of up to 200 mG.

  18. In vitro evaluation and intra-articular administration of biodegradable microspheres containing naproxen sodium.

    Science.gov (United States)

    Bozdağ, S; Caliş, S; Kaş, H S; Ercan, M T; Peksoy, I; Hincal, A A

    2001-01-01

    The dispersion of non-steroidal antiinflammatory drugs (NSAIDs) into biodegradable polymeric matrices have been accepted as a good approach for obtaining a therapeutic effect in a predetermined period of time meanwhile minimizing the side effects of NSAIDs. In the present study, it was aimed to prepare Naproxen Sodium (NS), (a NSAID) loaded microsphere formulation using natural Bovine Serum Albumin (BSA) and synthetic biodegradable polymers such as poly(lactide-co-glycolic acid) (PLGA) (50:50 MW 34,000 and 88,000 Da) for intra-articular administration, and to study the retention of the drug at the site of injection in the knee joint. NS incorporated microspheres were evaluated in vitro for particle size (the mean particle size; for BSA microspheres, 10.0 +/- 0.3 microm, for PLGA microspheres, 9.0 +/- 0.2 and 5.0 +/- 0.1 microm for MW 34,000 and 88,000 Da, respectively), yield value, drug loading, surface morphology and drug release. For in vivo studies, monoarticular arthritis was induced in the left knee joints of rabbits by using ovalbumin and Freund's Complete Adjuvant as antigen and adjuvant. A certain time (4 days) is allowed for the formation of arthritis in the knee joints, then the NS loaded microspheres were injected directly into the articular cavity. At specific time points, gamma scintigrams were obtained to determine the residence time of the microspheres in knee joints, in order to determine the most suitable formulation. This study indicated that PLGA, a synthetic polymer, is more promising than the natural type BSA microspheres for an effective cure of mono-articular arthritis in rabbits.

  19. Development of Risperidone PLGA Microspheres

    Directory of Open Access Journals (Sweden)

    Susan D’Souza

    2014-01-01

    Full Text Available The aim of this study was to design and evaluate biodegradable PLGA microspheres for sustained delivery of Risperidone, with an eventual goal of avoiding combination therapy for the treatment of schizophrenia. Two PLGA copolymers (50 : 50 and 75 : 25 were used to prepare four microsphere formulations of Risperidone. The microspheres were characterized by several in vitro techniques. In vivo studies in male Sprague-Dawley rats at 20 and 40 mg/kg doses revealed that all formulations exhibited an initial burst followed by sustained release of the active moiety. Additionally, formulations prepared with 50 : 50 PLGA had a shorter duration of action and lower cumulative AUC levels than the 75 : 25 PLGA microspheres. A simulation of multiple dosing at weekly or 15-day regimen revealed pulsatile behavior for all formulations with steady state being achieved by the second dose. Overall, the clinical use of Formulations A, B, C, or D will eliminate the need for combination oral therapy and reduce time to achieve steady state, with a smaller washout period upon cessation of therapy. Results of this study prove the suitability of using PLGA copolymers of varying composition and molecular weight to develop sustained release formulations that can tailor in vivo behavior and enhance pharmacological effectiveness of the drug.

  20. Evanescently Coupled Rectangular Microresonators in Silicon-on-Insulator with High Q-Values: Experimental Characterization

    Directory of Open Access Journals (Sweden)

    Manuel Mendez-Astudillo

    2017-04-01

    Full Text Available We report on evanescently coupled rectangular microresonators with dimensions up to 20 × 10 μm2 in silicon-on-insulator in an add-drop filter configuration. The influence of the geometrical parameters of the device was experimentally characterized and a high Q value of 13,000 was demonstrated as well as the multimode optical resonance characteristics in the drop port. We also show a 95% energy transfer between ports when the device is operated in TM-polarization and determine the full symmetry of the device by using an eight-port configuration, allowing the drop waveguide to be placed on any of its sides, providing a way to filter and route optical signals. We used the FDTD method to analyze the device and e-beam lithography and dry etching techniques for fabrication.

  1. Vertical integration of high-Q silicon nitride microresonators into silicon-on-insulator platform.

    Science.gov (United States)

    Li, Qing; Eftekhar, Ali A; Sodagar, Majid; Xia, Zhixuan; Atabaki, Amir H; Adibi, Ali

    2013-07-29

    We demonstrate a vertical integration of high-Q silicon nitride microresonators into the silicon-on-insulator platform for applications at the telecommunication wavelengths. Low-loss silicon nitride films with a thickness of 400 nm are successfully grown, enabling compact silicon nitride microresonators with ultra-high intrinsic Qs (~ 6 × 10(6) for 60 μm radius and ~ 2 × 10(7) for 240 μm radius). The coupling between the silicon nitride microresonator and the underneath silicon waveguide is based on evanescent coupling with silicon dioxide as buffer. Selective coupling to a desired radial mode of the silicon nitride microresonator is also achievable using a pulley coupling scheme. In this work, a 60-μm-radius silicon nitride microresonator has been successfully integrated into the silicon-on-insulator platform, showing a single-mode operation with an intrinsic Q of 2 × 10(6).

  2. Low Cost SU8 Based Above IC Process for High Q RF Power Inductors Integration

    International Nuclear Information System (INIS)

    Ghannam, A.; Bourrier, D.; Viallon, Ch.; Parra, Th.

    2011-01-01

    This paper presents a new process for integration of high-Q RF power inductors above low resistivity silicon substrates. The process uses the SU8 resin as a dielectric layer. The aim of using the SU8 is to form thick dielectric layer that can enhance the performance of the inductors. The flexibility of the process enables the possibility to realize complex shaped planar inductors with various dielectric and metal thicknesses to meet the requirements of the application. Q values of 55 at 5 GHz has been demonstrated for an inductance value of 0.8 nH using a 60 μm thick SU8 layer and 30 μm thick copper ribbons. (author)

  3. HiQ - A high-Q diffractometer for PDF measurements

    International Nuclear Information System (INIS)

    Brunelli, M.; Fischer, H.E.; Gaehler, R.; Chatterji, T.

    2011-01-01

    The local structure of many important functional materials is often different from the average structure, as revealed by diffraction, due to, e.g. doping, mixed site occupancy, or formation of time-dependent local distortions. To get information on both the average and the local structures one needs to perform a joint Rietveld and PDF (Pair Distribution Function) analysis of the total scattering, for which we need data to Q = 30 - 35 Angstroms with Δd/d ∼ 3*10 -3 . Here, we describe how the hot-source diffractometer D4 can be adapted to achieve this capability, and outline one possible design of a dedicated high-Q diffractometer at the ILL (Laue Langevin Institute), using the vacant inclined hot-neutron beam IH2. (authors)

  4. Beam induced rf cavity transient voltage

    International Nuclear Information System (INIS)

    Kramer, S.L.; Wang, J.M.

    1998-10-01

    The authors calculate the transient voltage induced in a radio frequency cavity by the injection of a relativistic bunched beam into a circular accelerator. A simplified model of the beam induced voltage, using a single tone current signal, is generated and compared with the voltage induced by a more realistic model of a point-like bunched beam. The high Q limit of the bunched beam model is shown to be related simply to the simplified model. Both models are shown to induce voltages at the resonant frequency ω r of the cavity and at an integer multiple of the bunch revolution frequency (i.e. the accelerating frequency for powered cavity operation) hω ο . The presence of two nearby frequencies in the cavity leads to a modulation of the carrier wave exp(hω ο t). A special emphasis is placed in this paper on studying the modulation function. These models prove useful for computing the transient voltage induced in superconducting rf cavities, which was the motivation behind this research. The modulation of the transient cavity voltage discussed in this paper is the physical basis of the recently observed and explained new kinds of longitudinal rigid dipole mode which differs from the conventional Robinson mode

  5. Preparing microspheres of actinide nitrides from carbon containing oxide sols

    International Nuclear Information System (INIS)

    Triggiani, L.V.

    1975-01-01

    A process is given for preparing uranium nitride, uranium oxynitride, and uranium carboxynitride microspheres and the microspheres as compositions of matter. The microspheres are prepared from carbide sols by reduction and nitriding steps. (Official Gazette)

  6. 'Parity effect' based generation of Schrodinger cat like states in high-Q microcavity

    International Nuclear Information System (INIS)

    Napoli, A.; Messina, A.

    1999-01-01

    It has been very recently shown that the dynamics of a two-level atom coupled to a bimodal degenerate cavity field by two-photon processes, is characterized by an interesting nonclassical dynamical behavior christened ''parity effect''. This effect consists in the fact that if the cavity field is prepared leaving one mode in its vacuum state and exciting the other one in a generic linear combination of even number states only, or odd number states only, then there exists an appropriate intensity-dependent interval of time after which the bimodal cavity exhibits macroscopically different parity-dependent quantum features. We show that this nonclassical effect is at the origin of the possibility of generating Schrodinger cat like states of the bimodal field appropriately selecting its initial conditions

  7. Chitosan Microspheres as Radiolabeled Delivery Devices

    International Nuclear Information System (INIS)

    Permtermsin, Chalermsin; Ngamprayad, Tippanan; Phumkhem, Sudkanung; Srinuttrakul, Wannee; Kewsuwan, Prartana

    2007-08-01

    Full text: This study optimized conditions for preparing, characterizing, radiolabeled of chitosan microspheres and the biodistribution of 99mTc-Chitosan microspheres after intravenous administration. Particle size distribution of the microspheres was determined by light scattering. Zeta potential was studied by dynamic light scattering and electrophoresis technique. Biodistribution studies were performed by radiolabeling using 99mTc. The results shown that geometric mean diameter of the microspheres was found to be 77.26?1.96 ?m. Microsphere surface charge of chitosan microspheres was positive charge and zeta potential was 25.80 ? 0.46 mV. The labeling efficiency for this condition was more than 95% and under this condition was stable for at least 6 h. Radioactivity

  8. In vitro Evaluation of Nateglinide-Loaded Microspheres Formulated ...

    African Journals Online (AJOL)

    Keywords: Nateglinide, Microspheres, Micromeritics, Drug release, Ionic ... Oral drug delivery systems (DDS) are commonly divided into immediate release and modified release systems. ..... Albumin Microspheres for Potential Intramuscular.

  9. Evaluation of radiolabelled microspheres as digesta markers

    International Nuclear Information System (INIS)

    Young, B.A.; Turner, B.V.; Dixon, A.E.; Exley, D.M.; Young, S.B.; Abidin, Z.

    1991-01-01

    The suitability of microspheres as markers for measuring digesta kinetics in sheep was examined. Microspheres offer advantages of uniformity of size and density, and stability during passage through the gastrointestinal tract. They are commercially available labelled with the choice of one of eleven different radionuclides and can be easily measured in digesta and faecal material. Tests comparing several types of digesta markers gave different measures of kinetic parameters when the measurements were made concurrently in the same sheep. However, concurrent measurements derived from use of microspheres were consistent. Microspheres offer a new alternative for digestive studies. (author). 19 refs, 4 tabs

  10. Spin squeezing and entanglement in a dispersive cavity

    International Nuclear Information System (INIS)

    Deb, R. N.; Abdalla, M. Sebawe; Hassan, S. S.; Nayak, N.

    2006-01-01

    We consider a system of N two-level atoms (spins) interacting with the radiation field in a dispersive but high-Q cavity. Under an adiabatic condition, the interaction Hamiltonian reduces to a function of spin operators which is capable of producing spin squeezing. For a bipartite system (N=2), the expressions for spin squeezing get very simple, giving a clear indication of close to 100% noise reduction. We analyse this squeezing as a measure of bipartite entanglement

  11. Fiber-Optic Refractometer Based on an Etched High-Q ?-Phase-Shifted Fiber-Bragg-Grating

    OpenAIRE

    Zhang, Qi; Ianno, Natale J.; Han, Ming

    2013-01-01

    We present a compact and highly-sensitive fiber-optic refractometer based on a high-Q p-phase-shifted fiber-Bragg-grating (pFBG) that is chemically etched to the core of the fiber. Due to the p phase-shift, a strong pFBG forms a high-Q optical resonator and the reflection spectrum features an extremely narrow notch that can be used for highly sensitivity refractive index measurement. The etched pFBG demonstrated here has a diameter of ~9.3 μm and a length of only 7 mm, leading to a refractive...

  12. Nucleon form factors at high q2 within constituent quark models

    International Nuclear Information System (INIS)

    Desplanques, B.; Silvestre-Brac, B.; Cano, F.; Noguera, S.; Gonzalez, P.; .

    2000-01-01

    The nucleon form factors are calculated using a non-relativistic description in terms of constituent quarks. The emphasis is put on present numerical methods used to solve the three-body problem in order to reliably predict the expected asymptotic behavior of form factors. Nucleon wave functions obtained in the hyperspherical formalism or employing Faddeev equations have been considered. While a q -8 behavior is expected at high q for a quark-quark force behaving like 1/r at short distances, it is found that the hyper central approximation in the hyperspherical formalism (K = 0) leads to a q -7 behavior. An infinite set of waves would be required to get the correct behavior. Solutions of the Faddeev equations lead to the q -8 behavior. The coefficient of the corresponding term, however, depends on the number of partial waves retained in the Faddeev amplitude. The convergence to the asymptotic behavior has also been studied. Approximate expressions characterizing this one have been derived. From the comparison with the most complete Faddeev calculation, a validity range is inferred for restricted calculations. Refs. 46 (author)

  13. Glass microspheres for medical applications

    Science.gov (United States)

    Conzone, Samuel David

    Radioactive dysprosium lithium borate glass microspheres have been developed as biodegradable radiation delivery vehicles for the radiation synovectomy treatment of rheumatoid arthritis. Once injected into a diseased joint, the microspheres deliver a potent dose of radiation to the diseased tissue, while a non-uniform chemical reaction converts the glass into an amorphous, porous, hydrated dysprosium phosphate reaction product. The non-radioactive, lithium-borate component is dissolved from the glass (up to 94% weight loss), while the radioactive 165Dy reacts with phosphate anions in the body fluids, and becomes "chemically" trapped in a solid, dysprosium phosphate reaction product that has the same size as the un-reacted glass microsphere. Ethylene diamine tetraacetate (EDTA) chelation therapy can be used to dissolve the dysprosium phosphate reaction product after the radiation delivery has subsided. The dysprosium phosphate reaction product, which formed in vivo in the joint of a Sprague-Dawley rat, was dissolved by EDTA chelation therapy in 100 Gy) of localized beta radiation to a treatment site within the body, followed by complete biodegradability. The non-uniform reaction process is a desirable characteristic for a biodegradable radiation delivery vehicle, but it is also a novel material synthesis technique that can convert a glass to a highly porous materials with widely varying chemical composition by simple, low-temperature, glass/solution reaction. The reaction product formed by nonuniform reaction occupies the same volume as the un-reacted glass, and after drying for 1 h at 300°C, has a specific surface area of ≈200 m2/g, a pore size of ≈30 nm, and a nominal crushing strength of ≈10 MPa. Finally, rhenium glass microspheres, composed of micron-sized, metallic rhenium particles dispersed within a magnesium alumino borate glass matrix were produced by sintering ReO2 powder and glass frit at 1050°C. A 50 mg injection of radioactive rhenium glass

  14. Microsphere estimates of blood flow: Methodological considerations

    International Nuclear Information System (INIS)

    von Ritter, C.; Hinder, R.A.; Womack, W.; Bauerfeind, P.; Fimmel, C.J.; Kvietys, P.R.; Granger, D.N.; Blum, A.L.

    1988-01-01

    The microsphere technique is a standard method for measuring blood flow in experimental animals. Sporadic reports have appeared outlining the limitations of this method. In this study the authors have systematically assessed the effect of blood withdrawals for reference sampling, microsphere numbers, and anesthesia on blood flow estimates using radioactive microspheres in dogs. Experiments were performed on 18 conscious and 12 anesthetized dogs. Four blood flow estimates were performed over 120 min using 1 x 10 6 microspheres each time. The effects of excessive numbers of microspheres pentobarbital sodium anesthesia, and replacement of volume loss for reference samples with dextran 70 were assessed. In both conscious and anesthetized dogs a progressive decrease in gastric mucosal blood flow and cardiac output was observed over 120 min. This was also observed in the pancreas in conscious dogs. The major factor responsible for these changes was the volume loss due to the reference sample withdrawals. Replacement of the withdrawn blood with dextran 70 led to stable blood flows to all organs. The injection of excessive numbers of microspheres did not modify hemodynamics to a greater extent than did the injection of 4 million microspheres. Anesthesia exerted no influence on blood flow other than raising coronary flow. The authors conclude that although blood flow to the gastric mucosa and the pancreas is sensitive to the minor hemodynamic changes associated with the microsphere technique, replacement of volume loss for reference samples ensures stable blood flow to all organs over a 120-min period

  15. Thermal analysis of iron hydroxide microspheres

    International Nuclear Information System (INIS)

    Turcanu, C.N.; Cornescu, M.

    1979-03-01

    The thermal treatment is an important step in the preparative technology of the iron oxids microspheres with well established mechanical, physical and chemical characteristics. The first indications on the heating procedure have been obtained from the thermal analysis on iron hydroxide microspheres prepared by the support precipitation and internal gelification methods. (author)

  16. Encapsulated PDMS microspheres with reactive handles

    DEFF Research Database (Denmark)

    Gonzalez, Lidia; Ma, Baoguang; Li, Li

    2014-01-01

    , cured PDMS microspheres are coated with poly(methyl methacrylate) using a chemical process (solvent evaporation technique). Three solvents are used in three different experiments: dichloromethane, tetrahydrofuran, and acetone. The composition and morphology of the cured PDMS microspheres and PMMA coated...

  17. Microencapsulation and microspheres for food applications

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2015-01-01

    This book provides an update on the latest developments, challenges, and opportunities in the highly expanding field of microencapsulation and microspheres for food applications, examining the various types of microspheres and microcapsules essential to those who need to develop stable and

  18. Micromachined Microwave Cavity Resonator Filters for 5G: a Feasibility Study

    NARCIS (Netherlands)

    Kemenade, van R.; Smolders, A.B.; Hon, de B.P.

    2015-01-01

    Micromachined microwave cavity filters offer a light-weight, high-Q and highly integrated alternative in the frequency range of 20 GHz–100 GHz as compared to conventional filter types. The filter technology shows potential for use in 5G portable devices and as such, the design of a duplexer

  19. U3O8 microspheres sintering kinetics

    International Nuclear Information System (INIS)

    Godoy, A.L.E.

    1986-01-01

    U 3 O 8 microspheres sintering kinetics was determined using a hot-stage optical microscopy apparatus, able to reach temperature up to 1350 0 C in controlled atmospheres. The sintered material had its microstructure analysed by optical and electron microscopy. The microspheres were characterized initialy utilizing X-ray diffractometry and thermogravimetry. The equation which describes the microspheres shrinkage in function of the time was obtained using finite difference analysis X-ray diffractometry indicated hexagonal structure for the microspheres main starting material, ammonium diuranate thermogravimetric analysis showed reduction of this material to U 3 O 8 at 600 0 C. Ceramography results showed 5 hours sintered microspheres grain sizes G vary with the temperature. Sintered U 3 O 8 micrographs compared with published results for UO 2 , indicate similar homogeneity microstructural characteristics and suggest the processed micorspheres to be potentially useful as nuclear fuels. (Author) [pt

  20. Magnetic susceptibility characterisation of superparamagnetic microspheres

    Science.gov (United States)

    Grob, David Tim; Wise, Naomi; Oduwole, Olayinka; Sheard, Steve

    2018-04-01

    The separation of magnetic materials in microsystems using magnetophoresis has increased in popularity. The wide variety and availability of magnetic beads has fuelled this drive. It is important to know the magnetic characteristics of the microspheres in order to accurately use them in separation processes integrated on a lab-on-a-chip device. To investigate the magnetic susceptibility of magnetic microspheres, the magnetic responsiveness of three types of Dynabeads microspheres were tested using two different approaches. The magnetophoretic mobility of individual microspheres is studied using a particle tracking system and the magnetization of each type of Dynabeads microsphere is measured using SQUID relaxometry. The magnetic beads' susceptibility is obtained at four different applied magnetic fields in the range of 38-70 mT for both the mobility and SQUID measurements. The susceptibility values in both approaches show a consistent magnetic field dependence.

  1. Formation of model hepatocellular aggregates in a hydrogel scaffold using degradable genipin crosslinked gelatin microspheres as cell carriers

    International Nuclear Information System (INIS)

    Lau, Ting Ting; Lee, Li Qi Priscilyn; Leong, Wenyan; Wang, Dong-An

    2012-01-01

    Primary hepatocyte is probably the preferred cell for cell therapy in liver regeneration. However, its non-ideal proliferation capacity and rapid loss of phenotype during 2D culture compromises the quality and quantity of the transplanted hepatocytes, resulting in variable success rates of this treatment. Many studies have shown that the formation of 3D hepatocellular spheroids aids in the maintenance of liver-specific functions in hepatocytes. However, many of the methodologies employed require a sophisticated set-up or specialized equipment which makes it uneconomical to scale up for clinical applications. In this study, we have developed dual-functioning genipin crosslinked gelatin microspheres that serve as cell carriers as well as porogens for delivering the model cells and also for creating cavities. The cells were first seeded onto genipin crosslinked gelatin microspheres for attachment, followed by encapsulation in alginate hydrogel. Collagenase, MMP-9, was introduced either in the culture media or mixed with alginate precursor solution to allow microsphere degradation for creating cavities within the gel bulk. Accordingly, the cells proliferate within the cavities, forming hepatocellular aggregates while the alginate hydrogel serves as a confinement, restricting the size and the shape of the aggregates to the size of the cavities. In addition, the final hepatocellular aggregates could be harvested from the system by removing the alginate hydrogel via citrate treatment. Therefore, this versatile platform not only has the advantage of injectability and simplicity, the cellular aggregates generated are in a controlled size and shape and can be extracted from the system. (paper)

  2. Packaged silica microsphere-taper coupling system for robust thermal sensing application.

    Science.gov (United States)

    Yan, Ying-Zhan; Zou, Chang-Ling; Yan, Shu-Bin; Sun, Fang-Wen; Ji, Zhe; Liu, Jun; Zhang, Yu-Guang; Wang, Li; Xue, Chen-Yang; Zhang, Wen-Dong; Han, Zheng-Fu; Xiong, Ji-Jun

    2011-03-28

    We propose and realize a novel packaged microsphere-taper coupling structure (PMTCS) with a high quality factor (Q) up to 5×10(6) by using the low refractive index (RI) ultraviolet (UV) glue as the coating material. The optical loss of the PMTCS is analyzed experimentally and theoretically, which indicate that the Q is limited by the glue absorption and the radiation loss. Moreover, to verify the practicability of the PMTCS, thermal sensing experiments are carried out, showing the excellent convenience and anti-jamming ability of the PMTCS with a high temperature resolution of 1.1×10(-3) ◦C. The experiments also demonstrate that the PMTCS holds predominant advantages, such as the robustness, mobility, isolation, and the PMTCS can maintain the high Q for a long time. The above advantages make the PMTCS strikingly attractive and potential in the fiber-integrated sensors and laser.

  3. μ-'Diving suit' for liquid-phase high-Q resonant detection.

    Science.gov (United States)

    Yu, Haitao; Chen, Ying; Xu, Pengcheng; Xu, Tiegang; Bao, Yuyang; Li, Xinxin

    2016-03-07

    A resonant cantilever sensor is, for the first time, dressed in a water-proof 'diving suit' for real-time bio/chemical detection in liquid. The μ-'diving suit' technology can effectively avoid not only unsustainable resonance due to heavy liquid-damping, but also inevitable nonspecific adsorption on the cantilever body. Such a novel technology ensures long-time high-Q resonance of the cantilever in solution environment for real-time trace-concentration bio/chemical detection and analysis. After the formation of the integrated resonant micro-cantilever, a patterned photoresist and hydrophobic parylene thin-film are sequentially formed on top of the cantilever as sacrificial layer and water-proof coat, respectively. After sacrificial-layer release, an air gap is formed between the parylene coat and the cantilever to protect the resonant cantilever from heavy liquid damping effect. Only a small sensing-pool area, located at the cantilever free-end and locally coated with specific sensing-material, is exposed to the liquid analyte for gravimetric detection. The specifically adsorbed analyte mass can be real-time detected by recording the frequency-shift signal. In order to secure vibration movement of the cantilever and, simultaneously, reject liquid leakage from the sensing-pool region, a hydrophobic parylene made narrow slit structure is designed surrounding the sensing-pool. The anti-leakage effect of the narrow slit and damping limited resonance Q-factor are modelled and optimally designed. Integrated with electro-thermal resonance excitation and piezoresistive frequency readout, the cantilever is embedded in a micro-fluidic chip to form a lab-chip micro-system for liquid-phase bio/chemical detection. Experimental results show the Q-factor of 23 in water and longer than 20 hours liquid-phase continuous working time. Loaded with two kinds of sensing-materials at the sensing-pools, two types of sensing chips successfully show real-time liquid-phase detection to ppb

  4. Construction of the LITL cavity structure

    International Nuclear Information System (INIS)

    Itoh, S.; Masuda, S.; Ukai, Y.; Hirao, Y.

    1984-01-01

    This report presents briefly the mechanical consideration for the 100 MHz four-vane RFQ (radio frequency quadrupole accelerator) structure construction. At first, the theoretical vane shape required to obtain the RFQ electric field distribution was determined. A numerically controlled milling machine was employed for the precise machining of the complicated shape. The data sets for NC machining and for checking the size of three-dimensional coordinates were made up. A small vane model was machined by way of trial experiment to check the data to verify the circular interpolation programmed NC machining method, and to investigate cutter interference. The errors in the measurement in machining were less than +- 30 micrometer. The resonator tank is 56 cm in inner diameter and 138 cm in length, and is made of mild steel of 35 mm thickness. The inside wall was plated with copper thickly. Various conditions for the copper plating were investigated. Four vanes were assembled within the cavity of the RFQ. The vanes were built in the cavity tank with high dimensional accuracy. It was a matter of primary concern to design acceptable mechanical rf joints and select suitable rf contact elements for a high Q value of the RFQ resonator cavity. Finally, the Q value was measured, and was 10,600. The cavity was able to be evacuated to 10 -7 Torr. (Kato, T.)

  5. Progress in Preparation of Monodisperse Polymer Microspheres

    Science.gov (United States)

    Zhang, Hongyan

    2017-12-01

    The monodisperse crosslinked polymer microspheres have attracted much attention because of their superior thermal and solvent resistance, mechanical strength, surface activity and adsorption properties. They are of wide prospects for using in many fields such as biomedicine, electronic science, information technology, analytical chemistry, standard measurement and environment protection etc. Functional polymer microspheres prepared by different methods have the outstanding surface property, quantum size effect and good potential future in applications with its designable structure, controlled size and large ratio of surface to volume. Scholars of all over the world have focused on this hot topic. The preparation method and research progress in functional polymer microspheres are addressed in the paper.

  6. High-Q contacted ring microcavities with scatterer-avoiding “wiggler” Bloch wave supermode fields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yangyang, E-mail: yangyang.liu@colorado.edu; Popović, Miloš A., E-mail: milos.popovic@colorado.edu [Nanophotonic Systems Laboratory, Department of Electrical, Computer, and Energy Engineering, University of Colorado, Boulder, Colorado 80309 (United States)

    2014-05-19

    High-Q ring resonators with contacts to the waveguide core provide a versatile platform for various applications in chip-scale optomechanics, thermo-, and electro-optics. We propose and demonstrate azimuthally periodic contacted ring resonators based on multi-mode Bloch matching that support contacts on both the inner and outer radius edges with small degradation to the optical quality factor (Q). Radiative coupling between degenerate modes of adjacent radial spatial order leads to imaginary frequency (Q) splitting and a scatterer avoiding high-Q “wiggler” supermode field. We experimentally measure Qs up to 258 000 in devices fabricated in a silicon device layer on buried oxide undercladding and up to 139 000 in devices fully suspended in air using an undercut step. Wiggler supermodes are true modes of the microphotonic system that offer additional degrees of freedom in electrical, thermal, and mechanical design.

  7. Carbon Nanofiber-Based, High-Frequency, High-Q, Miniaturized Mechanical Resonators

    Science.gov (United States)

    Kaul, Anupama B.; Epp, Larry W.; Bagge, Leif

    2011-01-01

    High Q resonators are a critical component of stable, low-noise communication systems, radar, and precise timing applications such as atomic clocks. In electronic resonators based on Si integrated circuits, resistive losses increase as a result of the continued reduction in device dimensions, which decreases their Q values. On the other hand, due to the mechanical construct of bulk acoustic wave (BAW) and surface acoustic wave (SAW) resonators, such loss mechanisms are absent, enabling higher Q-values for both BAW and SAW resonators compared to their electronic counterparts. The other advantages of mechanical resonators are their inherently higher radiation tolerance, a factor that makes them attractive for NASA s extreme environment planetary missions, for example to the Jovian environments where the radiation doses are at hostile levels. Despite these advantages, both BAW and SAW resonators suffer from low resonant frequencies and they are also physically large, which precludes their integration into miniaturized electronic systems. Because there is a need to move the resonant frequency of oscillators to the order of gigahertz, new technologies and materials are being investigated that will make performance at those frequencies attainable. By moving to nanoscale structures, in this case vertically oriented, cantilevered carbon nanotubes (CNTs), that have larger aspect ratios (length/thickness) and extremely high elastic moduli, it is possible to overcome the two disadvantages of both bulk acoustic wave (BAW) and surface acoustic wave (SAW) resonators. Nano-electro-mechanical systems (NEMS) that utilize high aspect ratio nanomaterials exhibiting high elastic moduli (e.g., carbon-based nanomaterials) benefit from high Qs, operate at high frequency, and have small force constants that translate to high responsivity that results in improved sensitivity, lower power consumption, and im - proved tunablity. NEMS resonators have recently been demonstrated using topdown

  8. Evaluation of Controlled Release Theophylline Microspheres ...

    African Journals Online (AJOL)

    Erah

    High drug/polymer ratio, low processing temperature and low HLB value of ... Keywords: Microsphere, Emulsion solvent evaporation, Theophylline, Temperature, ... evaporation, stirring rate, viscosity of ... organic solvent is removed from the.

  9. Intra-Cavity Total Reflection For High Sensitivity Measurement Of Optical Properties

    Science.gov (United States)

    Pipino, Andrew Charles Rule

    1999-11-16

    An optical cavity resonator device is provided for conducting sensitive murement of optical absorption by matter in any state with diffraction-limited spatial resolution through utilization of total internal reflection within a high-Q (high quality, low loss) optical cavity. Intracavity total reflection generates an evanescent wave that decays exponentially in space at a point external to the cavity, thereby providing a localized region where absorbing materials can be sensitively probed through alteration of the Q-factor of the otherwise isolated cavity. When a laser pulse is injected into the cavity and passes through the evanescent state, an amplitude loss resulting from absorption is incurred that reduces the lifetime of the pulse in the cavity. By monitoring the decay of the injected pulse, the absorption coefficient of manner within the evanescent wave region is accurately obtained from the decay time measurement.

  10. High-Q photonic resonators and electro-optic coupling using silicon-on-lithium-niobate

    Science.gov (United States)

    Witmer, Jeremy D.; Valery, Joseph A.; Arrangoiz-Arriola, Patricio; Sarabalis, Christopher J.; Hill, Jeff T.; Safavi-Naeini, Amir H.

    2017-04-01

    Future quantum networks, in which superconducting quantum processors are connected via optical links, will require microwave-to-optical photon converters that preserve entanglement. A doubly-resonant electro-optic modulator (EOM) is a promising platform to realize this conversion. Here, we present our progress towards building such a modulator by demonstrating the optically-resonant half of the device. We demonstrate high quality (Q) factor ring, disk and photonic crystal resonators using a hybrid silicon-on-lithium-niobate material system. Optical Q factors up to 730,000 are achieved, corresponding to propagation loss of 0.8 dB/cm. We also use the electro-optic effect to modulate the resonance frequency of a photonic crystal cavity, achieving a electro-optic modulation coefficient between 1 and 2 pm/V. In addition to quantum technology, we expect that our results will be useful both in traditional silicon photonics applications and in high-sensitivity acousto-optic devices.

  11. Segmented trapped vortex cavity

    Science.gov (United States)

    Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

    2010-01-01

    An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

  12. PLGA/alginate composite microspheres for hydrophilic protein delivery

    International Nuclear Information System (INIS)

    Zhai, Peng; Chen, X.B.; Schreyer, David J.

    2015-01-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility

  13. PLGA/alginate composite microspheres for hydrophilic protein delivery

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Peng [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Chen, X.B. [Department of Mechanical Engineering, University of Saskatchewan, S7N5A9 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada); Schreyer, David J., E-mail: david.schreyer@usask.ca [Department of Anatomy and Cell Biology, University of Saskatchewan, S7N5E5 (Canada); Division of Biomedical Engineering, University of Saskatchewan, S7N5A9 (Canada)

    2015-11-01

    Poly(lactic-co-glycolic acid) (PLGA) microspheres and PLGA/alginate composite microspheres were prepared by a novel double emulsion and solvent evaporation technique and loaded with bovine serum albumin (BSA) or rabbit anti-laminin antibody protein. The addition of alginate and the use of a surfactant during microsphere preparation increased the encapsulation efficiency and reduced the initial burst release of hydrophilic BSA. Confocal laser scanning microcopy (CLSM) of BSA-loaded PLGA/alginate composite microspheres showed that PLGA, alginate, and BSA were distributed throughout the depths of microspheres; no core/shell structure was observed. Scanning electron microscopy revealed that PLGA microspheres erode and degrade more quickly than PLGA/alginate composite microspheres. When loaded with anti-laminin antibody, the function of released antibody was well preserved in both PLGA and PLGA/alginate composite microspheres. The biocompatibility of PLGA and PLGA/alginate microspheres were examined using four types of cultured cell lines, representing different tissue types. Cell survival was variably affected by the inclusion of alginate in composite microspheres, possibly due to the sensitivity of different cell types to excess calcium that may be released from the calcium cross-linked alginate. - Highlights: • A double emulsion technique is used to prepare protein-loaded PLGA or PLGA/alginate microspheres. • PLGA, alginate and protein are distributed evenly within microsphere structure. • Addition of alginate improves loading efficiency and slows degradation and protein release. • PLGA/alginate microspheres have favorable biocompatibility.

  14. Numerical demonstration of neuromorphic computing with photonic crystal cavities.

    Science.gov (United States)

    Laporte, Floris; Katumba, Andrew; Dambre, Joni; Bienstman, Peter

    2018-04-02

    We propose a new design for a passive photonic reservoir computer on a silicon photonics chip which can be used in the context of optical communication applications, and study it through detailed numerical simulations. The design consists of a photonic crystal cavity with a quarter-stadium shape, which is known to foster interesting mixing dynamics. These mixing properties turn out to be very useful for memory-dependent optical signal processing tasks, such as header recognition. The proposed, ultra-compact photonic crystal cavity exhibits a memory of up to 6 bits, while simultaneously accepting bitrates in a wide region of operation. Moreover, because of the inherent low losses in a high-Q photonic crystal cavity, the proposed design is very power efficient.

  15. DEGRADATION AND INTRAHEPATIC COMPATIBILITY OF ALBUMIN-HEPARIN CONJUGATE MICROSPHERES

    NARCIS (Netherlands)

    CREMERS, HFM; WOLF, RFE; BLAAUW, EH; SCHAKENRAAD, JM; LAM, KH; NIEUWENHUIS, P; VERRIJK, R; KWON, G; BAE, YH; KIM, SW; FEIJEN, J

    The in vitro degradation properties of glutaraldehyde cross-linked albumin and albumin-heparin conjugate microspheres (AMS and AHCMS respectively) were evaluated using light microscopy, turbidity measurements and heparin release determinations, showing that the microspheres are degraded by

  16. Fundamental tests in Cavity Quantum Electrodynamics

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    At the dawn of quantum physics, Einstein and Bohr had the dream to confine a photon in a box and to use this contraption in order to illustrate the strange laws of the quantum world. Cavity Quantum Electrodynamics has now made this dream real, allowing us to actually achieve in the laboratory variants of the thought experiments of the founding fathers of quantum theory. In our work at Ecole Normale Supérieure, we use a beam of Rydberg atoms to manipulate and probe non-destructively microwave photons trapped in a very high Q superconducting cavity. We realize ideal quantum non-demolition (QND) measurements of photon numbers, observe the radiation quantum jumps due to cavity relaxation and prepare non-classical fields such as Fock and Schrödinger cat states. Combining QND photon counting with a homodyne mixing method, we reconstruct the Wigner functions of these non-classical states and, by taking snapshots of these functions at increasing times, obtain movies of the decoherence process. These experiments ope...

  17. High-Q energy trapping of temperature-stable shear waves with Lamé cross-sectional polarization in a single crystal silicon waveguide

    Science.gov (United States)

    Tabrizian, R.; Daruwalla, A.; Ayazi, F.

    2016-03-01

    A multi-port electrostatically driven silicon acoustic cavity is implemented that efficiently traps the energy of a temperature-stable eigen-mode with Lamé cross-sectional polarization. Dispersive behavior of propagating and evanescent guided waves in a ⟨100⟩-aligned single crystal silicon waveguide is used to engineer the acoustic energy distribution of a specific shear eigen-mode that is well known for its low temperature sensitivity when implemented in doped single crystal silicon. Such an acoustic energy trapping in the central region of the acoustic cavity geometry and far from substrate obviates the need for narrow tethers that are conventionally used for non-destructive and high quality factor (Q) energy suspension in MEMS resonators; therefore, the acoustically engineered waveguide can simultaneously serve as in-situ self-oven by passing large uniformly distributed DC currents through its body and without any concern about perturbing the mode shape or deforming narrow supports. Such a stable thermo-structural performance besides large turnover temperatures than can be realized in Lamé eigen-modes make this device suitable for implementation of ultra-stable oven-controlled oscillators. 78 MHz prototypes implemented in arsenic-doped single crystal silicon substrates with different resistivity are transduced by in- and out-of-plane narrow-gap capacitive ports, showing high Q of ˜43k. The low resistivity device shows an overall temperature-induced frequency drift of 200 ppm over the range of -20 °C to 80 °C, which is ˜15× smaller compared to overall frequency drift measured for the similar yet high resistivity device in the same temperature range. Furthermore, a frequency tuning of ˜2100 ppm is achieved in high resistivity device by passing 45 mA DC current through its body. Continuous operation of the device under such a self-ovenizing current over 10 days did not induce frequency instability or degradation in Q.

  18. Analytical and semi-analytical formalism for the voltage and the current sources of a superconducting cavity under dynamic detuning

    CERN Document Server

    Doleans, M

    2003-01-01

    Elliptical superconducting radio frequency (SRF) cavities are sensitive to frequency detuning because they have a high Q value in comparison with normal conducting cavities and weak mechanical properties. Radiation pressure on the cavity walls, microphonics, and tuning system are possible sources of dynamic detuning during SRF cavity-pulsed operation. A general analytic relation between the cavity voltage, the dynamic detuning function, and the RF control function is developed. This expression for the voltage envelope in a cavity under dynamic detuning and dynamic RF controls is analytically expressed through an integral formulation. A semi-analytical scheme is derived to calculate the voltage behavior in any practical case. Examples of voltage envelope behavior for different cases of dynamic detuning and RF control functions are shown. The RF control function for a cavity under dynamic detuning is also investigated and as an application various filling schemes are presented.

  19. Biocompatibility of Polyhydroxybutyrate Microspheres: in vitro and in vivo Evaluation

    OpenAIRE

    Shishatskaya, Ekaterina I.; Voinova, Olga N.; Goreva, Anastasya V.; Mogilnaya, Olga A.; Volova, Tatiana G.

    2008-01-01

    Microspheres have been prepared from the resorbable linear polyester of β-hydroxybutyric acid (polyhydroxybutyrate, PHB) by the solvent evaporation technique and investigated in vitro and in vivo. Biocompatibility of the microspheres has been proved in tests in the culture of mouse fibroblast cell line NIH 3Т3 and in experiments on intramuscular implantation of the microspheres to Wistar rats for 3 months. Tissue response to the implantation of polymeric microspheres has been found to consist...

  20. Rifapentine-linezolid-loaded PLGA microspheres for interventional therapy of cavitary pulmonary tuberculosis: preparation and in vitro characterization.

    Science.gov (United States)

    Huang, Jieyun; Chen, Zhi; Li, Ying; Li, Li; Zhang, Guangyu

    2017-01-01

    In this study, we aimed to design controlled-release microspheres for the treatment of cavitary pulmonary tuberculosis (TB) for solving the issues of poor drug delivery and short duration maintained at effective drug concentration during bronchoscopic interventional therapy. We fabricated rifapentine-linezolid-loaded poly(lactic acid-co-glycolic acid) microspheres (RLPMs) using the oil-in-water emulsion solvent evaporation method and assessed their in vitro release as well as the bronchial mucosal retention characteristics. The microspheres are spherical in shape with a circular concave on the surface. The particle size of RLPMs was 27.38±1.28 μm. The drug loading of rifapentine and linezolid was 18.51±0.26 and 8.42%±0.24%, respectively, while the encapsulation efficiencies were 55.53±0.78 and 16.87%±0.47%, respectively (n=3). During the burst release phase of the in vitro release test, 21.37%±0.68% rifapentine was released in 3 days and 43.56%±2.54% linezolid was released in 1 day. Then, both the drugs entered the sustained release phase. Finally, the cumulative percentage release of rifapentine and linezolid in 14 days was 27.61±1.52 and 51.01%±3.31%, respectively (n=3). Bronchoscopic observation revealed that the controlled-release microspheres could slowly release the drugs and retain them on the surface of bronchial mucosa of canines for 20 days. These results indicated that the fabricated microspheres exhibited a significant sustained release effect and could effectively retain the drugs on the surface of bronchial mucosa. Therefore, this study provides a theoretical and practical foundation for the development of fabricated microspheres loaded with multiple anti-TB drugs in the bronchoscopic interventional therapy of cavity pulmonary TB.

  1. Fano resonances in a high-Q terahertz whispering-gallery mode resonator coupled to a multi-mode waveguide.

    Science.gov (United States)

    Vogt, Dominik Walter; Leonhardt, Rainer

    2017-11-01

    We report on Fano resonances in a high-quality (Q) whispering-gallery mode (WGM) spherical resonator coupled to a multi-mode waveguide in the terahertz (THz) frequency range. The asymmetric line shape and phase of the Fano resonances detected with coherent continuous-wave (CW) THz spectroscopy measurements are in excellent agreement with the analytical model. A very high Q factor of 1600, and a finesse of 22 at critical coupling is observed around 0.35 THz. To the best of our knowledge this is the highest Q factor ever reported for a THz WGM resonator.

  2. Preparation and Characterization of Sugar Cane Wax Microspheres ...

    African Journals Online (AJOL)

    ... and characterize indomethacin (IM) microspheres prepared with sugar cane wax microsperes. Methods: Microspheres were prepared by melt-emulsified dispersion and cooling-induced solidification method. The microspheres were characterized by scanning electron microscopy (SEM) and differntial scanning calorimetry ...

  3. Preparation of polymer microspheres by radiation-induced polymerization

    International Nuclear Information System (INIS)

    Naka, Y.; Yamamoto, Y.; Yoshida, Y.; Tagawa, S.

    1995-01-01

    Cross-liking monomer, diethylene glycol dimethacrylate gives microspheres from organic solution by radiation-induced polymerization. /One of the remarkable result is that the number of the microspheres is not changing during the polymerization. Ethyl methacrylate, maleic anhydride, styrene and acrylamide are used as comonomers. These comonomers give the microspheres in the range of 0 to 0.4 as mol fractions. (author)

  4. Flexible Microsphere-Embedded Film for Microsphere-Enhanced Raman Spectroscopy.

    Science.gov (United States)

    Xing, Cheng; Yan, Yinzhou; Feng, Chao; Xu, Jiayu; Dong, Peng; Guan, Wei; Zeng, Yong; Zhao, Yan; Jiang, Yijian

    2017-09-27

    Dielectric microspheres with extraordinary microscale optical properties, such as photonic nanojets, optical whispering-gallery modes (WGMs), and directional antennas, have drawn interest in many research fields. Microsphere-enhanced Raman spectroscopy (MERS) is an alternative approach for enhanced Raman detection by dielectric microstructures. Unfortunately, fabrication of microsphere monolayer arrays is the major challenge of MERS for practical applications on various specimen surfaces. Here we report a microsphere-embedded film (MF) by immersing a highly refractive microsphere monolayer array in the poly(dimethylsiloxane) (PDMS) film as a flexible MERS sensing platform for one- to three-dimensional (1D to 3D) specimen surfaces. The directional antennas and wave-guided whispering-gallery modes (WG-WGMs) contribute to the majority of Raman enhancement by the MFs. Moreover, the MF can be coupled with surface-enhanced Raman spectroscopy (SERS) to provide an extra >10-fold enhancement. The limit of detection is therefore improved for sensing of crystal violet (CV) and Sudan I molecules in aqueous solutions at concentrations down to 10 -7 M. A hybrid dual-layer microsphere enhancer, constructed by depositing a MF onto a microsphere monolayer array, is also demonstrated, wherein the WG-WGMs become dominant and boost the enhancement ratio >50-fold. The present work opens up new opportunities for design of cost-effective and flexible MERS sensing platforms as individual or associated techniques toward practical applications in ultrasensitive Raman detection.

  5. Structural studies of WO3-TeO2 glasses by high-Q-neutron diffraction and Raman spectroscopy

    International Nuclear Information System (INIS)

    Khanna, A.; Kaur, A.; Krishna, P.S.R.; Shinde, A.B.

    2013-01-01

    Glasses from the system: xWO 3 -(100-x)TeO 2 (x=15, 20 and 25 mol %) were prepared by melt quenching technique and characterized by density, UV-visible absorption spectroscopy, Differential Scanning Calorimetry (DSC), Raman spectroscopy and high-Q neutron diffraction measurements. Glass density and glass transition temperature increased with increase in WO 3 concentration, Raman spectroscopy indicated the conversion of TeO 4 units into TeO 3 units with increase in WO 3 content. The increase in glass transition temperature with the incorporation of WO 3 was attributed to the increase in average bond strength of the glass network since the bond dissociation energy of W-O bonds (672 kJ/mol) is significantly higher than that of Te-O bonds (376 kJ/mol). UV-visible studies found a very strong optical absorption band due to W 6+ ions, just below the absorption edge. High-Q neutron diffraction measurements were performed on glasses and radial distribution function analyses revealed changes in W-O and Te-O correlations in the glass network. The findings about changes in glass structure from neutron diffraction studies were consistent with structural information obtained from Raman spectroscopy and structure-property correlations were made. (author)

  6. Fiber-optic refractometer based on an etched high-Q π-phase-shifted fiber-Bragg-grating.

    Science.gov (United States)

    Zhang, Qi; Ianno, Natale J; Han, Ming

    2013-07-10

    We present a compact and highly-sensitive fiber-optic refractometer based on a high-Q π-phase-shifted fiber-Bragg-grating (πFBG) that is chemically etched to the core of the fiber. Due to the p phase-shift, a strong πFBG forms a high-Q optical resonator and the reflection spectrum features an extremely narrow notch that can be used for highly sensitivity refractive index measurement. The etched πFBG demonstrated here has a diameter of ~9.3 μm and a length of only 7 mm, leading to a refractive index responsivity of 2.9 nm/RIU (RIU: refractive index unit) at an ambient refractive index of 1.318. The reflection spectrum of the etched πFBG features an extremely narrow notch with a linewidth of only 2.1 pm in water centered at ~1,550 nm, corresponding to a Q-factor of 7.4 × 10(5), which allows for potentially significantly improved sensitivity over refractometers based on regular fiber Bragg gratings.

  7. Fiber-Optic Refractometer Based on an Etched High-Q π-Phase-Shifted Fiber-Bragg-Grating

    Directory of Open Access Journals (Sweden)

    Ming Han

    2013-07-01

    Full Text Available We present a compact and highly-sensitive fiber-optic refractometer based on a high-Q p-phase-shifted fiber-Bragg-grating (pFBG that is chemically etched to the core of the fiber. Due to the p phase-shift, a strong pFBG forms a high-Q optical resonator and the reflection spectrum features an extremely narrow notch that can be used for highly sensitivity refractive index measurement. The etched pFBG demonstrated here has a diameter of ~9.3 μm and a length of only 7 mm, leading to a refractive index responsivity of 2.9 nm/RIU (RIU: refractive index unit at an ambient refractive index of 1.318. The reflection spectrum of the etched pFBG features an extremely narrow notch with a linewidth of only 2.1 pm in water centered at ~1,550 nm, corresponding to a Q-factor of 7.4 ´ 105, which allows for potentially significantly improved sensitivity over refractometers based on regular fiber Bragg gratings.

  8. Rifapentine-linezolid-loaded PLGA microspheres for interventional therapy of cavitary pulmonary tuberculosis: preparation and in vitro characterization

    Directory of Open Access Journals (Sweden)

    Huang J

    2017-03-01

    a significant sustained release effect and could effectively retain the drugs on the surface of bronchial mucosa. Therefore, this study provides a theoretical and practical foundation for the development of fabricated microspheres loaded with multiple anti-TB drugs in the bronchoscopic interventional therapy of cavity pulmonary TB. Keywords: rifapentine, linezolid, poly(lactic-co-glycolic acid, controlled-release microspheres, bronchoscopy, cavity pulmonary tuberculosis

  9. The quest for high-gradient superconducting cavities

    International Nuclear Information System (INIS)

    Padamsee, H.

    1999-01-01

    Superconducting RF cavities excel in applications requiring continuous waves or long pulse voltages. Since power losses in the walls of the cavity increase as the square of the accelerating voltage, copper cavities become uneconomical as demand for high continuous wave voltage grows with particle energy. For these reasons, RF superconductivity has become an important technology for high energy and high luminosity accelerators. The state of art in performance of sheet metal niobium cavities is best represented by the statistics of more than 300 5-cell, 1.5-GHz cavities built for CEBAF. Key aspects responsible for the outstanding performance of the CEBAF cavities set are the anti-multipactor, elliptical cell shape, good fabrication and welding techniques, high thermal conductivity niobium, and clean surface preparation. On average, field emission starts at the electric field of 8.7 MV/m, but there is a large spread, even though the cavities received nominally the same surface treatment and assembly procedures. In some cavities, field emission was detected as low as 3 MV/m. In others, it was found to be as high as 19 MV/m. As we will discuss, the reason for the large spread in the gradients is the large spread in emitter characteristics and the random occurrence of emitters on the surface. One important phenomenon that limits the achievable RF magnetic field is thermal breakdown of superconductivity, originating at sub-millimeter-size regions of high RF loss, called defects. Simulation reveal that if the defect is a normal conducting region of 200 mm radius, it will break down at 5 MV/m. Producing high gradients and high Q in superconducting cavities demands excellent control of material properties and surface cleanliness. The spread in gradients that arises from the random occurrence of defects and emitters must be reduced. It will be important to improve installation procedures to preserve the excellent gradients now obtained in laboratory test in vertical cryostats

  10. Hydrogen transport and storage in engineered glass microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rambach, G.D.

    1995-04-18

    New, high strength glass microspheres filled with pressurized hydrogen exhibit densities which make them attractive for bulk hydrogen storage and transport. The membrane tensile stress at failure for our engineered glass microspheres is about 150,000 psi, permitting a threefold increase in pressure limit and storage capacity above commercial microspheres, which have been studied a decade ago and have been shown to fail at membrane stresses of 50,000 psi. Our analysis relating glass microspheres for hydrogen transport with infrastructure and economics, indicate that pressurized microspheres can be economically competitive with other forms of bulk rail and truck transport such as pressurized tube transports and liquid hydrogen trailers.

  11. Improved reactor cavity

    International Nuclear Information System (INIS)

    Katz, L.R.; Demarchais, W.E.

    1984-01-01

    A reactor pressure vessel disposed in a cavity has coolant inlet or outlet pipes extending through passages in the cavity walls and welded to pressure nozzles. The cavity wall has means for directing fluid away from a break at a weld away from the pressure vessel, and means for inhibiting flow of fluid toward the vessel. (author)

  12. A microsphere suspension model of metamaterial fluids

    Directory of Open Access Journals (Sweden)

    Qian Duan

    2017-05-01

    Full Text Available Drawing an analogy to the liquid phase of natural materials, we theoretically propose a microsphere suspension model to realize a metamaterial fluid with artificial electromagnetic indexes. By immersing high-ε, micrometer-sized dielectric spheres in a low-ε insulating oil, the structured fluid exhibits liquid-like properties from dispersing phase as well as the isotropic negative electromagnetic parameters caused by Mie resonances from dispersed microspheres. The work presented here will benefit the development of structured fluids toward metamaterials.

  13. Albumin microspheres labeled with Ga-67 by chelation: concise communication

    International Nuclear Information System (INIS)

    Hnatowich, D.J.; Schlegel, P.

    1981-01-01

    Albumin microspheres have been synthesized with EDTA and DTPA chelating groups covalently bound to their surface. The microspheres may be labeled with Ga-67 at high yield (97 +- 2%) by transcomplexation from a 0.1 M Ga-67 acetate solution. With EDTA microspheres the resulting label dissociates only slightly after 24 hr in 50% plasma at 37 0 C, whereas with DTPA microspheres the label shows no detectable dissociation over this period. By contrast, microspheres without chelating groups lose their label virtually completely under these conditions. Following intravenous administration of sized Ga-67 DTPA microspheres in mice, about (84 +- 16)% of the activity localizes in the lungs at 5 min, with (60 +- 7)% remaining after 2 h. Since labeling is by chelation, the microspheres may also be tagged with other metallic radionuclides

  14. Enlargement of Tuning Range in a Ferrite-Tuned Cavity Through Superposed Orthogonal and Parallel Magnetic Bias

    CERN Document Server

    Vollinger, C

    2013-01-01

    Conventional ferrite-tuned cavities operate either with bias fields that are orthogonal or parallel to the magnetic RF-field. For a cavity that tunes rapidly over an overall frequency range around 100-400 MHz with high Q, we use ferrite garnets exposed to an innovative new biasing method consisting of a superposition of perpendicular and parallel magnetic fields. This method leads to a significant enlargement of the high-Q cavity tuning range by defining an operation point close to the magnetic saturation and thus improving ferrite material behaviour. A further advantage of this technique is the fast tuning speed resulting from the fact that tuning is carried out either with pure parallel biasing, or together with a very small change of operating point from perpendicular bias. In this paper, several scaled test models of ferrite-filled resonators are shown; measurements on the set-ups are compared and discussed.

  15. An engineering two-mode field NOON state in cavity QED

    Energy Technology Data Exchange (ETDEWEB)

    Saif, Farhan; Rameez-ul-Islam [Department of Electronics, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Khosa, Ashfaq H [Centre for Quantum Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan)

    2010-01-14

    We generate highly non-classical entangled two-mode field states of the type (|n{sub X},0{sub Y}>+-|0{sub X},n{sub Y}>)/sq root2 by utilizing an atomic analogue of the Mach-Zehnder interferometer, where quantized fields in the high-Q cavities act as beam splitters and mirrors. We discuss that the probability for the production of the desired states may approach a value close to unity under presently available experimental conditions.

  16. Temporal Bell-type inequalities for two-level Rydberg atoms coupled to a high-Q resonator

    International Nuclear Information System (INIS)

    Huelga, S.F.; Marshall, T.W.; Santos, E.

    1996-01-01

    Following the strategy of showing specific quantum effects by means of the violation of a classical inequality, a pair of Bell-type inequalities is derived on the basis of certain additional assumptions, whose plausibility is discussed in detail. Such inequalities are violated by the quantum mechanical predictions for the interaction of a two-level Rydberg atom with a single mode sustained by a high-Q resonator. The experimental conditions required in order to show the existence of forbidden values, according to a hidden variables formalism, in a real experiment are analyzed for various initial field statistics. In particular, the revival dynamics expected for the interaction with a coherent field leads to classically forbidden values, which would indicate a purely quantum effect. copyright 1996 The American Physical Society

  17. Measurement of charged and neutral current e-p deep inelastic scattering cross sections at high Q2

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-03-01

    Deep inelastic e - p scattering has been studied in both the charged current (CC) and neutral current (NC) reactions at momentum transfers squared, Q 2 , between 400 GeV 2 and the kinematic limit of 87500 GeV 2 using the ZEUS detector at the HERA ep collider. The CC and NC total cross sections, the NC to CC cross section ratio, and the differential cross sections, dσ/dQ 2 , are presented. For Q 2 ∝M W 2 , where M W is the mass of the W boson, the CC and NC cross sections have comparable magnitudes, demonstrating the equal strengths of the weak and electromagnetic interactions at high Q 2 . The Q 2 dependence of the CC cross section determines the mass term in the CC propagator to be M W =76±16±13 GeV. (orig.)

  18. Theoretical study of high-Q Fano resonance and extrinsic chirality in an ultrathin Babinet-inverted metasurface

    Science.gov (United States)

    Wang, Feng; Wang, Zhengping; Shi, Jinhui

    2014-10-01

    A high-Q Fano resonance and giant extrinsic chirality have been demonstrated in an ultrathin Babinet-inverted metasurface composed of asymmetrical split ring apertures (ASRAs) perforated through a metal plate based on the full-wave simulations. The performance of the Fano resonance at normal incidence strongly depends on the asymmetry of the ASRA. The quality factor is larger than 1000 and the local field enhancement is an order of 104. For oblique incidence, giant extrinsic chirality can be achieved in the Babinet-inverted metasurface. It reveals a cross-polarization transmission band with a ripple-free peak and also a spectrum split for large angles of incidence. The electromagnetic response of the metasurface can be easily tuned via angles of incidence and asymmetry. The proposed ASRA metasurface is of importance to develop many metamaterial-based devices, such as filters and circular polarizers.

  19. Gastroretentive Floating Microspheres of Silymarin: Preparation and ...

    African Journals Online (AJOL)

    Erah

    simulated gastric fluid for at least 12 h, and, therefore, could potentially ... systems (GRFDDS) have a bulk density ... The objective of this work was to develop and characterise gastroretentive floating microspheres of silymarin which, following oral administration, would exhibit .... hydrochloric acid to maintain sink conditions.

  20. Structuring of diamond films using microsphere lithography

    Czech Academy of Sciences Publication Activity Database

    Domonkos, Mária; Ižák, Tibor; Štolcová, L.; Proška, J.; Demo, Pavel; Kromka, Alexander

    2014-01-01

    Roč. 54, č. 5 (2014), s. 320-324 ISSN 1210-2709 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : nanostructuring * diamond thin films * polystyrene microspheres * reactive ion etching * scanning electron microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism

  1. Method and apparatus for producing microspherical particles

    International Nuclear Information System (INIS)

    Egli, W.; Bailey, W.H.; Leary, D.F.; Lansley, R.J.

    1979-01-01

    This invention relates generally to a method and apparatus for producing microspherical particles and more particularly to a method and apparatus which are particularly useful in connection with the sol-gel process for the production of nuclear fuel kernels. (U.K.)

  2. MICROSPHERE SIZE INFLUENCES THE FOREIGN BODY REACTION

    NARCIS (Netherlands)

    Zandstra, J.; Hiemstra, C.; Petersen, A. H.; Zuidema, J.; van Beuge, M. M.; Rodriguez, S.; Lathuile, A. A. R.; Veldhuis, G. J.; Steendam, R.; Bank, R. A.; Popa, E. R.

    2014-01-01

    Biodegradable poly-(DL-lactide-co-glycolide) (PLGA) microspheres (MSP) are attractive candidate vehicles for site-specific or systemic sustained release of therapeutic compounds. This release may be altered by the host's foreign body reaction (FBR), which is dependent on the characteristics of the

  3. Beat-Frequency/Microsphere Medical Ultrasonic Imaging

    Science.gov (United States)

    Yost, William T.; Cantrell, John H.; Pretlow, Robert A., III

    1995-01-01

    Medical ultrasonic imaging system designed to provide quantitative data on various flows of blood in chambers, blood vessels, muscles, and tissues of heart. Sensitive enough to yield readings on flows of blood in heart even when microspheres used as ultrasonic contrast agents injected far from heart and diluted by circulation of blood elsewhere in body.

  4. Synthesis of double-shelled sea urchin-like yolk-shell Fe3O4/TiO2/Au microspheres and their catalytic applications

    International Nuclear Information System (INIS)

    Li, Jie; Tan, Li; Wang, Ge; Yang, Mu

    2015-01-01

    Double-shelled sea urchin-like yolk-shell Fe 3 O 4 /TiO 2 /Au microspheres were successfully synthesized through loading Au nanoparticles on the Fe 3 O 4 /TiO 2 support by a in situ reduction of HAuCl 4 with NaBH 4 aqueous solution. These microspheres possess tunable cavity size, adjustable shell layers, high structural stability and large specific surface area. The Au nanoparticles of approximately 5 nm in diameter were loaded both on the TiO 2 nanofibers and inside the cavities of sea urchin-like yolk-shell Fe 3 O 4 /TiO 2 microspheres. The sea urchin-like structure composed of TiO 2 nanofibers ensure the good distribution of the Au nanoparticles, while the novel double-shelled yolk-shell structure guarantees the high stability of the Au nanoparticles. Furthermore, the Fe 3 O 4 magnetic core facilitates the convenient recovery of the catalyst by applying an external magnetic field. The Fe 3 O 4 /TiO 2 /Au microspheres display excellent activities and recycling properties in the catalytic reduction of 4-nitrophenol (4-NP): the rate constant is 1.84 min −1 and turnover frequency is 5457 h −1 . (paper)

  5. Measurement of Microwave Parameters of a Superconducting Niobium Cavity

    Science.gov (United States)

    Azaryan, N. S.; Baturitskii, M. A.; Budagov, Yu. A.; Demin, D. L.; Dem‧yanov, S. E.; Karpovich, V. A.; Kniga, V. V.; Krivosheev, R. M.; Lyubetskii, N. V.; Maksimov, S. I.; Pobol‧, I. L.; Rodionova, V. N.; Shirkov, G. D.; Shumeiko, N. M.; Yurevich, S. V.

    2017-01-01

    This paper describes a method for direct measurement of the amplitude-frequency characteristics and the Q factor of empty superconducting niobium radio frequency Tesla-type cavities. An automated measuring complex that permits recording the superconductivity effect and measuring high Q values has been developed. Measurements have been made of the Q factors of the investigated objects (the first domestic 1.3-GHz niobium cavities) at a level no lower than 0.1·109 (with a maximum value of 1.2·1010) and a level of relative losses lower than 130 dB (with a minimum factor of 139.7 dB) at liquid nitrogen temperature.

  6. Hydrogen transport and storage in engineered glass microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rambach, G.D.

    1994-04-20

    New, high-strength, hollow, glass microspheres filled with pressurized hydrogen exhibit storage densities which make them attractive for bulk hydrogen storage and transport. The hoop stress at failure of our engineered glass microspheres is about 150,000 psi, permitting a three-fold increase in pressure limit and storage capacity above commercial microspheres, which fail at wall stresses of 50,000 psi. For this project, microsphere material and structure will be optimized for storage capacity and charge/discharge kinetics to improve their commercial practicality. Microsphere production scale up will be performed, directed towards large-scale commercial use. Our analysis relating glass microspheres for hydrogen transport with infrastructure and economics` indicate that pressurized microspheres can be economically competitive with other forms of bulk rail and truck transport such as hydride beds, cryocarbons and pressurized tube transports. For microspheres made from advanced materials and processes, analysis will also be performed to identify the appropriate applications of the microspheres considering property variables, and different hydrogen infrastructure, end use, production and market scenarios. This report presents some of the recent modelling results for large beds of glass microspheres in hydrogen storage applications. It includes plans for experiments to identify the properties relevant to large-bed hydrogen transport and storage applications, of the best, currently producible, glass microspheres. This work began in March, 1994. Project successes will be manifest in the matching of cur-rent glass microspheres with a useful application in hydrogen bulk transport and storage, and in developing microsphere materials and processes that increase the storage density and reduce the storage energy requirement.

  7. Bloch-wave engineered submicron-diameter quantum-dot micropillars for cavity QED experiments

    DEFF Research Database (Denmark)

    Gregersen, Niels; Lermer, Matthias; Reitzenstein, Stephan

    2013-01-01

    The semiconductor micropillar is attractive for cavity QED experiments. For strong coupling, the figure of merit is proportional to Q/√V, and a design combining a high Q and a low mode volume V is thus desired. However, for the standard submicron diameter design, poor mode matching between the ca...... the cavity and the DBR Bloch mode limits the Q. We present a novel adiabatic design where Bloch-wave engineering is employed to improve the mode matching, allowing the demonstration of a record-high vacuum Rabi splitting of 85 μeV and a Q of 13600 for a 850 nm diameter micropillar....

  8. High field tests of 1.3 GHz niobium superconducting cavities

    International Nuclear Information System (INIS)

    Kako, Eiji; Noguchi, Shuichi; Ono, Masaaki

    1993-01-01

    Four single-cell cavities prepared by various surface treatments have been tested repeatedly since 1991. A maximum accelerating gradient of 25.1 MV/m with a high Q 0 value of ∼10 10 was successfully achieved after heat treatment at 1400degC. A temperature mapping system with a high thermal sensitivity under superfluid helium was developed to understand phenomena limiting a maximum accelerating gradient. The cavity performances and the phenomena at high fields are reported in this paper. (author)

  9. In vitro evaluation of biodegradable microspheres with surface-bound ligands.

    Science.gov (United States)

    Keegan, Mark E; Royce, Sara M; Fahmy, Tarek; Saltzman, W Mark

    2006-02-21

    Protein ligands were conjugated to the surface of biodegradable microspheres. These microsphere-ligand conjugates were then used in two in vitro model systems to evaluate the effect of conjugated ligands on microsphere behavior. Microsphere retention in agarose columns was increased by ligands on the microsphere surface specific for receptors on the agarose matrix. In another experiment, conjugating the lectin Ulex europaeus agglutinin 1 to the microsphere surface increased microsphere adhesion to Caco-2 monolayers compared to control microspheres. This increase in microsphere adhesion was negated by co-administration of l-fucose, indicating that the increase in adhesion is due to specific interaction of the ligand with carbohydrate receptors on the cell surface. These results demonstrate that the ligands conjugated to the microspheres maintain their receptor binding activity and are present on the microsphere surface at a density sufficient to target the microspheres to both monolayers and three-dimensional matrices bearing complementary receptors.

  10. The LHC superconducting cavities

    CERN Document Server

    Boussard, Daniel; Häbel, E; Kindermann, H P; Losito, R; Marque, S; Rödel, V; Stirbet, M

    1999-01-01

    The LHC RF system, which must handle high intensity (0.5 A d.c.) beams, makes use of superconducting single-cell cavities, best suited to minimizing the effects of periodic transient beam loading. There will be eight cavities per beam, each capable of delivering 2 MV (5 MV/m accelerating field) at 400 MHz. The cavities themselves are now being manufactured by industry, using niobium-on-copper technology which gives full satisfaction at LEP. A cavity unit includes a helium tank (4.5 K operating temperature) built around a cavity cell, RF and HOM couplers and a mechanical tuner, all housed in a modular cryostat. Four-unit modules are ultimately foreseen for the LHC (two per beam), while at present a prototype version with two complete units is being extensively tested. In addition to a detailed description of the cavity and its ancillary equipment, the first test results of the prototype will be reported.

  11. LEP copper accelerating cavities

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

  12. Optically Levitated Microspheres as a Probe for New Interactions

    Science.gov (United States)

    Rider, Alexander; Moore, David; Blakemore, Charles; Lu, Marie; Gratta, Giorgio

    2016-03-01

    We are developing novel techniques to probe new interactions at micron distances using optically levitated dielectric microspheres. Levitated microspheres are an ideal probe for short-range interactions because they are suspended using the radiation pressure at the focus of a laser beam, which means that the microspheres can be precisely manipulated and isolated from the surrounding environment at high vacuum. We have performed a search for unknown charged particles bound within the bulk of the microspheres. Currently, we are searching for the presence of a Chameleon field postulated to explain the presence of dark energy in the universe. In the future we plan to use optically levitated microspheres to search for micron length-scale gravity like interactions that could couple between a microsphere and another mass. We will present resent results from these experiments and plans for future searches for new interactions.

  13. Hydrogen transport and storage in engineered glass microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rambach, G.D.

    1995-02-28

    New, high strength glass microspheres filled with pressurized hydrogen exhibit densities which make them attractive for bulk hydrogen storage and transport. The membrane tensile stress at failure for engineered glass microspheres is about 150,000 psi, permitting a three-fold increase in pressure limit and storage capacity above commercial microspheres, which have been studied a decade ago and have been shown to fail at membrane stresses of 50,000 psi. This analysis relating glass microspheres for hydrogen transport with infrastructure and economics, indicate that pressurized microspheres can be economically competitive with other forms of bulk rail and truck transport such as pressurized tube transports and liquid hydrogen trailers. This paper will describe the matching of current glass microspheres with the useful application in commercial hydrogen bulk transport and storage.

  14. On active disturbance rejection based control design for superconducting RF cavities

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, John; Morris, Dan; Usher, Nathan [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University, East Lansing, MI 48824-1321 (United States); Gao, Zhiqiang, E-mail: z.gao@csuohio.edu [Center for Advanced Control Technologies, Fenn College of Engineering, Cleveland State University, Cleveland, OH 44115-2214 (United States); Zhao Shen; Nicoletti, Achille; Zheng Qinling [Center for Advanced Control Technologies, Fenn College of Engineering, Cleveland State University, Cleveland, OH 44115-2214 (United States)

    2011-07-01

    Superconducting RF (SRF) cavities are key components of modern linear particle accelerators. The National Superconducting Cyclotron Laboratory (NSCL) is building a 3 MeV/u re-accelerator (ReA3) using SRF cavities. Lightly loaded SRF cavities have very small bandwidths (high Q) making them very sensitive to mechanical perturbations whether external or self-induced. Additionally, some cavity types exhibit mechanical responses to perturbations that lead to high-order non-stationary transfer functions resulting in very complex control problems. A control system that can adapt to the changing perturbing conditions and transfer functions of these systems would be ideal. This paper describes the application of a control technique known as 'Active Disturbance Rejection Control' (ARDC) to this problem.

  15. Physical and mechanical metallurgy of high purity Nb for accelerator cavities

    International Nuclear Information System (INIS)

    Bieler, T.R.; Wright, N.T.; Pourboghrat, F.; Compton, C.; Hartwig, K.T.; Baars, D.; Zamiri, A.; Chandrasekaran, S.; Darbandi, P.; Jiang, H.; Skoug, E.; Balachandran, S.; Ice, G.E.; Liu, W.

    2010-01-01

    In the past decade, high Q values have been achieved in high purity Nb superconducting radio frequency (SRF) cavities. Fundamental understanding of the physical metallurgy of Nb that enables these achievements is beginning to reveal what challenges remain to establish reproducible and cost-effective production of high performance SRF cavities. Recent studies of dislocation substructure development and effects of recrystallization arising from welding and heat treatments and their correlations with cavity performance are considered. With better fundamental understanding of the effects of dislocation substructure evolution and recrystallization on electron and phonon conduction, as well as the interior and surface states, it will be possible to design optimal processing paths for cost-effective performance using approaches such as hydroforming, which minimizes or eliminates welds in a cavity.

  16. Investigation of Plasma Etching for Superconducting RF Cavities Surface Preparation. Final Report

    International Nuclear Information System (INIS)

    Vuskovic, Leposava

    2009-01-01

    Our results show that plasma-treated samples are comparable or superior to a BCP sample, both in the size of features and sharpness of the boundaries between individual features at the surface. Plasma treatment of bulk Nb cavities is a promising technique for microwave cavities preparation used in particle acceleration application. Etching rates are sufficiently high to enable efficient removal of mechanically damaged surface layer with high reproducibility. No impurities are deposited on the bulk Nb surface during plasma treatment. Surface topology characteristic are promising for complex cavity geometry, since discharge conforms the profile of the reaction chamber. In view of these experimental results, we propose plasma treatment for producing microwave cavities with high Q factor instead of using bulk Nb treated with wet etching process.

  17. Physical and mechanical metallurgy of high purity Nb for accelerator cavities

    Directory of Open Access Journals (Sweden)

    T. R. Bieler

    2010-03-01

    Full Text Available In the past decade, high Q values have been achieved in high purity Nb superconducting radio frequency (SRF cavities. Fundamental understanding of the physical metallurgy of Nb that enables these achievements is beginning to reveal what challenges remain to establish reproducible and cost-effective production of high performance SRF cavities. Recent studies of dislocation substructure development and effects of recrystallization arising from welding and heat treatments and their correlations with cavity performance are considered. With better fundamental understanding of the effects of dislocation substructure evolution and recrystallization on electron and phonon conduction, as well as the interior and surface states, it will be possible to design optimal processing paths for cost-effective performance using approaches such as hydroforming, which minimizes or eliminates welds in a cavity.

  18. Beat frequency ultrasonic microsphere contrast agent detection system

    Science.gov (United States)

    Pretlow, III, Robert A. (Inventor); Yost, William T. (Inventor); Cantrell, Jr., John H. (Inventor)

    1997-01-01

    A system for and method of detecting and measuring concentrations of an ultrasonically-reflective microsphere contrast agent involving detecting non-linear sum and difference beat frequencies produced by the microspheres when two impinging signals with non-identical frequencies are combined by mixing. These beat frequencies can be used for a variety of applications such as detecting the presence of and measuring the flow rates of biological fluids and industrial liquids, including determining the concentration level of microspheres in the myocardium.

  19. Microsphere formation in droplets using antisolvent vapour precipitation technique

    OpenAIRE

    Chew, Sean Jun Liang

    2017-01-01

    In previous studies, the antisolvent vapour precipitation method has been proven to produce uniformly sized lactose microspheres (1.0 µm) from a single droplet (1.2 mm diameter) at atmospheric pressure. These types of particles have potential applications in the pharmaceutical industry, especially due to their high dissolution rate. This project looked into the possibility of using antisolvent vapour precipitation to produce microspheres from finely atomised droplets. Microspheres in the sub-...

  20. Preparation of polystyrene microsphere with emulsion microencapsulation method

    International Nuclear Information System (INIS)

    Li Bo Zhang Lin; Zhang Zhganwen; You Dan; Wei Yun; Wang Chaoyang; Lin Bo; Shi Tao; Chu Qiaomei

    2003-01-01

    The preparation of hollow polystyrene microspheres that are used as inner shell of multi-shell plastic microspheres in the ICF experiments is focused on. The effects of surfactants, water-soluble polymer and electrolyte on the properties of resultant microspheres are studied. Based on these experiments, a fabricating procedure was established with which hollow microspheres were prepared with diameter about 150-3000 μm, wall thickness 0.8-15 μm and toughness Ra less than 4 nm. (authors)

  1. Intestinal absorption of PLAGA microspheres in the rat.

    Science.gov (United States)

    Damgé, C; Aprahamian, M; Marchais, H; Benoit, J P; Pinget, M

    1996-12-01

    Rhodamine B-labelled poly (DL-lactide-co-glycolide) (PLAGA) microspheres of 2 different sizes, 1-5 microns and 5-10 microns, were administered as a single dose (1.44 x 10(9) and 1.83 x 10(8) particles, respectively) into the ileal lumen of adult rats. The content of rhodamine in the mesenteric vein and ileal lumen was analysed periodically from 10 min to 48 h as well as the distribution of microspheres in the intestinal mucosa and various other tissues. The concentration of rhodamine decreased progressively in the intestinal lumen and was negligible after 24 h. The number of microspheres in the mesenteric vein increased rapidly and reached a maximum after 4 h whatever the size of the particles. It then decreased progressively, but more rapidly with microspheres > 5 microns than with microspheres PLAGA microspheres mainly crossed the intestinal mucosa at the site of Peyer's patches where microspheres of 5 microns were retained in the ileal lumen. A few small microspheres were occasionally observed in the epithelial cells. Only the smallest particles were recovered in the liver, lymph nodes and spleen while basement membranes were always labelled. It is concluded that PLAGA microspheres could be useful for the oral delivery of antigens if their size is between 1 and 5 microns.

  2. Preparation of porous zirconia microspheres by internal gelation method

    International Nuclear Information System (INIS)

    Pathak, Sachin S.; Pius, I.C.; Bhanushali, R.D.; Rao, T.V. Vittal; Mukerjee, S.K.

    2008-01-01

    A modified internal gelation process for the preparation of porous zirconia microspheres has been developed. The conventional method has been modified by adding a surfactant in the feed broth. The effects of variation of surfactant concentration, washing techniques and temperature of calcination on the pore volume and the surface area of the microspheres have been studied. The conditions were optimized to obtain porous stable microspheres suitable for various applications. The microspheres were characterized by surface area analysis, pore volume analysis, thermogravimetric analysis and X-ray diffraction. The ion exchange behavior was studied using pH titration

  3. Microsphere based improved sunscreen formulation of ethylhexyl methoxycinnamate.

    Science.gov (United States)

    Gogna, Deepak; Jain, Sunil K; Yadav, Awesh K; Agrawal, G P

    2007-04-01

    Polymethylmethacrylate (PMMA) microspheres of ethylhexyl methoxycinnamate (EHM) were prepared by emulsion solvent evaporation method to improve its photostability and effectiveness as sunscreening agent. Process parameters like stirring speed and aqueous polyvinyl alcohol (PVA) concentration were analyzed in order to optimize the formulations. Shape and surface morphology of the microspheres were examined using scanning electron microscopy. Particle size of the microspheres was determined using laser diffraction particle size analyzer. The PMMA microspheres of EHM were incorporated in water-removable cream base. The in vitro drug release of EHM in pH 7.4 was performed using dialysis membrane. Thin layer chromatography was performed to determine photostability of EHM inside the microspheres. The formulations were evaluated for sun protection factor (SPF) and minimum erythema dose (MED) in albino rats. Cream base formulation containing microspheres prepared using EHM:PMMA in ratio of 1:3 (C(3)) showed slowest drug (EHM) release and those prepared with EHM: PMMA in ratio of 1:1 showed fastest release. The cream base formulations containing EHM loaded microspheres had shown better SPF (more than 16.0) as compared to formulation C(d) that contained 3% free EHM as sunscreen agent and showed SPF 4.66. These studies revealed that the incorporation of EHM loaded PMMA microspheres into cream base had greatly increased the efficacy of sunscreen formulation approximately four times. Further, photostability was also shown to be improved in PMMA microspheres.

  4. Low pressure gas filling of laser fusion microspheres

    International Nuclear Information System (INIS)

    Koo, J.C.; Dressler, J.L.; Hendricks, C.D.

    1979-01-01

    In our laser fusion microsphere production, large, thin gel-microspheres are formed before the chemicals are fused into glass. In this transient stage,, the gel-microspheres are found to be highly permeable to argon and many other inert gases. When the gel transforms to glass, the argon gas, for example, is trapped within to form argon filled, fusion target quality, glass microspheres. On the average, the partial pressure of the argon fills attained in this process is around 2 x 10 4 Pa at room temperature

  5. Cavity design programs

    International Nuclear Information System (INIS)

    Nelson, E.M.

    1996-01-01

    Numerous computer programs are available to help accelerator physicists and engineers model and design accelerator cavities and other microwave components. This article discusses the problems these programs solve and the principles upon which these programs are based. Some examples of how these programs are used in the design of accelerator cavities are also given

  6. Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Suresh de, E-mail: suresh.desilva@unsw.edu.au [Southern Radiology Group, Radiology Department Sutherland Hospital (Australia); Mackie, Simon [Western General Hospital, Department of Urology (United Kingdom); Aslan, Peter [St George Hospital, Department of Urology (Australia); Cade, David [Sirtex Technology Pty Ltd (Australia); Delprado, Warick [Douglass Hanly Moir Pathology (Australia)

    2016-12-15

    BackgroundIntra-arterial brachytherapy with yttrium-90 ({sup 90}Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of {sup 90}Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model.MethodsIn each of six pigs, ~25–33 % of the kidney volume was embolized with {sup 90}Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8–9 weeks after the procedure to assess the locations of the microspheres and extent of tissue necrosis from {sup 90}Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed.ResultsKidneys embolized with {sup 90}Y-radioembolization decreased in mass by 30–70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the {sup 90}Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10{sup 6}) of bland microspheres.ConclusionThis study showed that radioembolization with {sup 90}Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of {sup 90}Y resin microspheres for the localized treatment of kidney tumors.

  7. A novel route for synthesis and growth formation of metal oxides microspheres: Insights from V_2O_3 microspheres

    International Nuclear Information System (INIS)

    Zhang, Yifu; Huang, Chi; Meng, Changgong; Hu, Tao

    2016-01-01

    Highly polydisperse V_2O_3 solid microspheres with large specific surface area were successfully synthesized via a facile hydrothermal decomposition of VOC_2O_4 solution. The morphology and composition were characterized by scanning electron microscopy (SEM), Energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). V_2O_3 microspheres display an obvious Mott phase transition at −128.5 °C (cooling curve) and −114.5 °C (heating curve). Some parameters including the reaction temperature, concentration of VOC_2O_4, reaction time, surfactant, H_2C_2O_4 and precursor were briefly discussed to reveal the formation of V_2O_3 microspheres. It was found that the precursor is crucial for the fabrication of microsphere. A self-assembly growth mechanism was suggested to explain the growth process of microspheres and the autogenic CO and CO_2 gas served as the soft templates. Furthermore, this route was developed to synthesize different metal oxides microspheres, and it was found that AlO(OH), Fe_3O_4, Fe_2O_3, Co_3O_4, Cr_2O_3, MoO_2 and WO_3 microspheres were obtained. All the results showed this process was successfully explored as a methodology to synthesize different metal oxides microspheres using the gas as the templates by this facile hydrothermal route. - Highlights: • Highly uniform V_2O_3 solid microspheres were synthesized. • V_2O_3 microspheres display an obvious Mott phase transition. • The autogenic CO and CO_2 gas served as the soft templates for designed synthesis. • AlO(OH), Fe_3O_4, Fe_2O_3, Co_3O_4, Cr_2O_3, MoO_2 and WO_3 microspheres were obtained. • A methodology to synthesize different metal oxides microspheres was developed.

  8. Histological Comparison of Kidney Tissue Following Radioembolization with Yttrium-90 Resin Microspheres and Embolization with Bland Microspheres

    International Nuclear Information System (INIS)

    Silva, Suresh de; Mackie, Simon; Aslan, Peter; Cade, David; Delprado, Warick

    2016-01-01

    BackgroundIntra-arterial brachytherapy with yttrium-90 ("9"0Y) resin microspheres (radioembolization) is a procedure to selectively deliver high-dose radiation to tumors. The purpose of this research was to compare the radioembolic effect of "9"0Y-radioembolization versus the embolic effect of bland microspheres in the porcine kidney model.MethodsIn each of six pigs, ~25–33 % of the kidney volume was embolized with "9"0Y resin microspheres and an equivalent number of bland microspheres in the contralateral kidney. Kidney volume was estimated visually from contrast-enhanced fluoroscopy imaging. Morphologic and histologic analysis was performed 8–9 weeks after the procedure to assess the locations of the microspheres and extent of tissue necrosis from "9"0Y-radioembolization and bland embolization. A semi-quantified evaluation of the non-acute peri-particle and perivascular tissue reaction was conducted. All guidelines for the care and use of animals were followed.ResultsKidneys embolized with "9"0Y-radioembolization decreased in mass by 30–70 % versus the contralateral kidney embolized with bland microspheres. These kidneys showed significant necrosis/fibrosis, avascularization, and glomerular atrophy in the immediate vicinity of the "9"0Y resin microspheres. By contrast, glomerular changes were not observed, even with clusters of bland microspheres in afferent arterioles. Evidence of a foreign body reaction was recorded in some kidneys with bland microspheres, and subcapsular scarring/infarction only with the highest load (4.96 × 10"6) of bland microspheres.ConclusionThis study showed that radioembolization with "9"0Y resin microspheres produces localized necrosis/fibrosis and loss of kidney mass in a porcine kidney model. This result supports the study of "9"0Y resin microspheres for the localized treatment of kidney tumors.

  9. Formation of coronal cavities

    International Nuclear Information System (INIS)

    An, C.H.; Suess, S.T.; Tandberg-Hanssen, E.; Steinolfson, R.S.

    1986-01-01

    A theoretical study of the formation of a coronal cavity and its relation to a quiescent prominence is presented. It is argued that the formation of a cavity is initiated by the condensation of plasma which is trapped by the coronal magnetic field in a closed streamer and which then flows down to the chromosphere along the field lines due to lack of stable magnetic support against gravity. The existence of a coronal cavity depends on the coronal magnetic field strength; with low strength, the plasma density is not high enough for condensation to occur. Furthermore, we suggest that prominence and cavity material is supplied from the chromospheric level. Whether a coronal cavity and a prominence coexist depends on the magnetic field configuration; a prominence requires stable magnetic support

  10. Neutron transmission measurements on hydrogen filled microspheres

    International Nuclear Information System (INIS)

    Dyrnjaja, Eva; Hummel, Stefan; Keding, Marcus; Smolle, Marie-Theres; Gerger, Joachim; Zawisky, Michael

    2014-01-01

    Hollow microspheres are promising candidates for future hydrogen storage technologies. Although the physical process for hydrogen diffusion through glass is well understood, measurements of static quantities (e.q. hydrogen pressure inside the spheres) as well as dynamic properties (e.g. diffusion rate of hydrogen through glass) are still difficult to handle due to the small size of the spheres (d≈15μm). For diffusion rate measurements, the long-term stability of the experiment is also mandatory due to the relatively slow diffusion rate. In this work, we present an accurate and long-term stable measurement technique for static and dynamic properties, using neutron radiography. Furthermore, possible applications for hydrogen filled microspheres within the scope of radiation issues are discussed

  11. Aptamer Based Microsphere Biosensor for Thrombin Detection

    Directory of Open Access Journals (Sweden)

    Xudong Fan

    2006-08-01

    Full Text Available We have developed an optical microsphere resonator biosensor using aptamer asreceptor for the measurement of the important biomolecule thrombin. The sphere surface ismodified with anti-thrombin aptamer, which has excellent binding affinity and selectivityfor thrombin. Binding of the thrombin at the sphere surface is monitored by the spectralposition of the microsphere’s whispering gallery mode resonances. A detection limit on theorder of 1 NIH Unit/mL is demonstrated. Control experiments with non-aptameroligonucleotide and BSA are also carried out to confirm the specific binding betweenaptamer and thrombin. We expect that this demonstration will lead to the development ofhighly sensitive biomarker sensors based on aptamer with lower cost and higher throughputthan current technology.

  12. Measurement of the neutral current reaction at high Q{sup 2} in the H1 experiment at HERA II

    Energy Technology Data Exchange (ETDEWEB)

    Shushkevich, Stanislav

    2012-12-15

    This thesis presents inclusive e{sup {+-}}p double and single differential cross section measurements for neutral current deep inelastic scattering of longitudinally polarized leptons on protons as a function of the negative four-momentum transfer squared Q{sup 2} and the Bjorken variable x. The data were collected in the years 2003-2007 in the H1 experiment at HERA with positively and negatively longitudinally polarized lepton beams of 27 GeV and a proton beam of 920 GeV corresponding to the centre-of-mass energy of {radical}(s)=319 GeV. The integrated luminosity is about 330 pb{sup -1}. An overview of the phenomenology of the deep inelastic scattering is given and the experimental apparatus is described. The NC cross section measurement procedure is presented and discussed in details. The measured cross sections are used to investigate electroweak effects at high Q{sup 2}. The proton structure function xF{sub 3}, sensitive to the valence quarks in the proton, is measured. The polarization effects sensitive to the chiral structure of neutral currents are investigated. The Standard Model predictions are found to be in a good agreement with the measurement.

  13. Measurement of high-Q2 neutral current cross-sections with longitudinally polarised positrons with the ZEUS detector

    International Nuclear Information System (INIS)

    Stewart, Trevor P.

    2012-07-01

    The cross sections for neutral current (NC) deep inelastic scattering (DIS) in e + p collisions with a longitudinally polarised positron beam are measured at high momentum transfer squared (Q 2 >185 GeV 2 ) at the ZEUS detector at HERA. The HERA accelerator provides e ± p collisions at a centre-of-mass energy of 318 GeV, which allows the weak contribution to the NC process to be studied at high Q 2 . The measurements are based on a data sample with an integrated luminosity of 135.5 pb -1 collected with the ZEUS detector in 2006 and 2007. The single differential NC cross sections dσ/dQ 2 , dσ/dx and dσ/dy and the reduced cross section σ are measured. The structure function xF 3 is determined by combining the e + p NC reduced cross sections with the previously measured e - p measurements. The interference structure function xF 3 γZ is extracted at Q 2 =1500 GeV 2 . The cross-section asymmetry between the positive and negative polarisation of the positron beam is measured and the parity violation effects of the electroweak interaction are observed. The predictions of the Standard Model of particle physics agree well with the measurements. (orig.)

  14. Measurement of high-Q{sup 2} neutral current cross-sections with longitudinally polarised positrons with the ZEUS detector

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Trevor P.

    2012-07-15

    The cross sections for neutral current (NC) deep inelastic scattering (DIS) in e{sup +}p collisions with a longitudinally polarised positron beam are measured at high momentum transfer squared (Q{sup 2}>185 GeV{sup 2}) at the ZEUS detector at HERA. The HERA accelerator provides e{sup {+-}}p collisions at a centre-of-mass energy of 318 GeV, which allows the weak contribution to the NC process to be studied at high Q{sup 2}. The measurements are based on a data sample with an integrated luminosity of 135.5 pb{sup -1} collected with the ZEUS detector in 2006 and 2007. The single differential NC cross sections d{sigma}/dQ{sup 2}, d{sigma}/dx and d{sigma}/dy and the reduced cross section {sigma} are measured. The structure function xF{sub 3} is determined by combining the e{sup +}p NC reduced cross sections with the previously measured e{sup -}p measurements. The interference structure function xF{sub 3}{sup {gamma}Z} is extracted at Q{sup 2}=1500 GeV{sup 2}. The cross-section asymmetry between the positive and negative polarisation of the positron beam is measured and the parity violation effects of the electroweak interaction are observed. The predictions of the Standard Model of particle physics agree well with the measurements. (orig.)

  15. Sputter coating of microspherical substrates by levitation

    Science.gov (United States)

    Lowe, A.T.; Hosford, C.D.

    Microspheres are substantially uniformly coated with metals or nonmetals by simltaneously levitating them and sputter coating them at total chamber pressures less than 1 torr. A collimated hole structure comprising a parallel array of upwardly projecting individual gas outlets is machined out to form a dimple. Glass microballoons,, which are particularly useful in laser fusion applications, can be substantially uniformly coated using the coating method and apparatus.

  16. Glass microspheres covering film: first field evaluations

    International Nuclear Information System (INIS)

    Magnani, G.; Filippi, F.

    2006-01-01

    A trial was carried out to evaluate, in the North-Centre of Italy, the behaviour in field of a new plastic covering film, prepared with the inclusion of empty glass microspheres (Solex). The trial was conducted on tomato (Lycopersicon esculentum L.) and eggplant (Solanum melongena L.). The new film was compared to a covering film with the same optical (diffuse light) and constitutional (co-extruded three layers EVA-WPE) characteristics. Since the first results, the innovative film showed a better behaviour than the control one. It presented light and thermal conditions (lower temperature during the day and slightly higher temperature in the night, compared to the control film) that allowed a better growth and yield than the control film. The growth analysis of tomato showed that plants grown under glass microsphere film had an higher growth rate (dry weight/days) and thickness of leaves compared to the control one. The yield of tomato and eggplant presented an increase in plants cultivated under the innovative film, especially for number and weight of fruits. The commercial quality did not show any differences between the films, except for the flesh hardness of tomato: this could be explained with the fact that the glass microspheres film provides environmental conditions avoiding plant stress during some stages of its cycle [it

  17. STRUCTURING OF DIAMOND FILMS USING MICROSPHERE LITHOGRAPHY

    Directory of Open Access Journals (Sweden)

    Mária Domonkos

    2014-10-01

    Full Text Available In this study, the structuring of micro- and nanocrystalline diamond thin films is demonstrated. The structuring of the diamond films is performed using the technique of microsphere lithography followed by reactive ion etching. Specifically, this paper presents a four-step fabrication process: diamond deposition (microwave plasma assisted chemical vapor deposition, mask preparation (by the standard Langmuir-Blodgett method, mask modification and diamond etching. A self-assembled monolayer of monodisperse polystyrene (PS microspheres with close-packed ordering is used as the primary template. Then the PS microspheres and the diamond films are processed in capacitively coupled radiofrequency plasma  using different plasma chemistries. This fabrication method illustrates the preparation of large arrays of periodic and homogeneous hillock-like structures. The surface morphology of processed diamond films is characterized by scanning electron microscopy and atomic force microscope. The potential applications of such diamond structures in various fields of nanotechnology are also briefly discussed.

  18. Yttrium-90 microsphere induced gastrointestinal tract ulceration

    Directory of Open Access Journals (Sweden)

    Rikabi Ali A

    2008-09-01

    Full Text Available Abstract Background Radiomicrosphere therapy (RT utilizing yttrium-90 (90Y microspheres has been shown to be an effective regional treatment for primary and secondary hepatic malignancies. We sought to determine a large academic institution's experience regarding the extent and frequency of gastrointestinal complications. Methods Between 2004 and 2007, 27 patients underwent RT for primary or secondary hepatic malignancies. Charts were subsequently reviewed to determine the incidence and severity of GI ulceration. Results Three patients presented with gastrointestinal bleeding and underwent upper endoscopy. Review of the pretreatment angiograms showed normal vascular anatomy in one patient, sclerosed hepatic vasculature in a patient who had undergone prior chemoembolization in a second, and an aberrant left hepatic artery in a third. None had undergone prophylactic gastroduodenal artery embolization. Endoscopic findings included erythema, mucosal erosions, and large gastric ulcers. Microspheres were visible on endoscopic biopsy. In two patients, gastric ulcers were persistent at the time of repeat endoscopy 1–4 months later despite proton pump inhibitor therapy. One elderly patient who refused surgical intervention died from recurrent hemorrhage. Conclusion Gastrointestinal ulceration is a known yet rarely reported complication of 90Y microsphere embolization with potentially life-threatening consequences. Once diagnosed, refractory ulcers should be considered for aggressive surgical management.

  19. Adsorption behavior of protein onto siloxane microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Liu Bailing [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China)]. E-mail: Blliuchem@hotmail.com; Cao Shunsheng [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China); Deng Xiaobo [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China); Li Songjun [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China); Luo Rong [Chengdu Institute of Organic Chemistry, Graduate School of CAS, Chinese Academy of Sciences, Chengdu 610041 (China)

    2006-09-15

    The siloxane microspheres with core-shell structure (PMMA/PMPS) (MMA, methyl methacrylate; MPS, 3-methacryloxypropyl-trimethoxysilane) have been prepared by dispersion polymerization as described in our previous work. In this paper, the developed poly(MMA-MPS) microspheres, as a carrier, are used to investigate the adsorption behavior of bovine serum albumin (BSA) on them. The Langmuir and Freundlich models have been applied to describe the adsorption behavior. The experimental results indicated that the presence of PMPS evidently increases the adsorption rate and the amount of protein, and it also influences the interaction of BSA molecules. The adsorption of BSA on the poly(MMA-MPS) microspheres seems to be sensitive to pH and ionic strength. The fittings curves from Langmuir and Freundlich models showed that the adsorption was actually more complicated than ideal situation because one or more interactions were involved in the process. For understanding the electronic contribution, the Zeta potential was used to measure the reactive system before and after protein adsorption.

  20. Adsorption behavior of protein onto siloxane microspheres

    International Nuclear Information System (INIS)

    Liu Bailing; Cao Shunsheng; Deng Xiaobo; Li Songjun; Luo Rong

    2006-01-01

    The siloxane microspheres with core-shell structure (PMMA/PMPS) (MMA, methyl methacrylate; MPS, 3-methacryloxypropyl-trimethoxysilane) have been prepared by dispersion polymerization as described in our previous work. In this paper, the developed poly(MMA-MPS) microspheres, as a carrier, are used to investigate the adsorption behavior of bovine serum albumin (BSA) on them. The Langmuir and Freundlich models have been applied to describe the adsorption behavior. The experimental results indicated that the presence of PMPS evidently increases the adsorption rate and the amount of protein, and it also influences the interaction of BSA molecules. The adsorption of BSA on the poly(MMA-MPS) microspheres seems to be sensitive to pH and ionic strength. The fittings curves from Langmuir and Freundlich models showed that the adsorption was actually more complicated than ideal situation because one or more interactions were involved in the process. For understanding the electronic contribution, the Zeta potential was used to measure the reactive system before and after protein adsorption

  1. Digital Measurement System for the HIE-Isolde Superconducting Accelerating Cavities

    CERN Document Server

    Elias, Michal

    Extensive R&D efforts are being invested at CERN into the fundamental science of the RF superconductivity, cavity design, niobium sputtering, coating and RF properties of superconducting cavities. Fast and precise characterization and measurements of RF parameters of the newly produced cavities is essential for advances with the cavity production. The currently deployed analogue measurement system based on an analogue phase discriminators and tracking RF generators is not optimal for efficient work at the SM18 superconducting cavity test stand. If exact properties of the cavity under test are not known a traditional feedback loop will not be able to find resonant frequency in a reasonable time or even at all. This is mainly due to a very high Q factor. The resonance peak is very narrow (fraction of a Hz at 100 MHz). If the resonant frequency is off by several bandwidths, small changes of the cavity field during the tuning will not be measureable. Also cavity field will react only very slowly to any change...

  2. SPS RF Accelerating Cavity

    CERN Multimedia

    1979-01-01

    This picture shows one of the 2 new cavities installed in 1978-1979. The main RF-system of the SPS comprises four cavities: two of 20 m length and two of 16.5 m length. They are all installed in one long straight section (LSS 3). These cavities are of the travelling-wave type operating at a centre frequency of 200.2 MHz. They are wideband, filling time about 700 ns and untuned. The power amplifiers, using tetrodes are installed in a surface building 200 m from the cavities. Initially only two cavities were installed, a third cavity was installed in 1978 and a forth one in 1979. The number of power amplifiers was also increased: to the first 2 MW plant a second 2 MW plant was added and by end 1979 there were 8 500 kW units combined in pairs to feed each of the 4 cavities with up to about 1 MW RF power, resulting in a total accelerating voltage of about 8 MV. See also 7412016X, 7412017X, 7411048X

  3. Superconducting TESLA cavities

    Directory of Open Access Journals (Sweden)

    B. Aune

    2000-09-01

    Full Text Available The conceptional design of the proposed linear electron-positron collider TESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with an accelerating gradient of E_{acc}≥25 MV/m at a quality factor Q_{0}≥5×10^{9}. The design goal for the cavities of the TESLA Test Facility (TTF linac was set to the more moderate value of E_{acc}≥15 MV/m. In a first series of 27 industrially produced TTF cavities the average gradient at Q_{0}=5×10^{9} was measured to be 20.1±6.2 MV/m, excluding a few cavities suffering from serious fabrication or material defects. In the second production of 24 TTF cavities, additional quality control measures were introduced, in particular, an eddy-current scan to eliminate niobium sheets with foreign material inclusions and stringent prescriptions for carrying out the electron-beam welds. The average gradient of these cavities at Q_{0}=5×10^{9} amounts to 25.0±3.2 MV/m with the exception of one cavity suffering from a weld defect. Hence only a moderate improvement in production and preparation techniques will be needed to meet the ambitious TESLA goal with an adequate safety margin. In this paper we present a detailed description of the design, fabrication, and preparation of the TESLA Test Facility cavities and their associated components and report on cavity performance in test cryostats and with electron beam in the TTF linac. The ongoing research and development towards higher gradients is briefly addressed.

  4. Cavity-enhanced spectroscopies

    CERN Document Server

    van Zee, Roger

    2003-01-01

    ""Cavity-Enhanced Spectroscopy"" discusses the use of optical resonators and lasers to make sensitive spectroscopic measurements. This volume is written by the researcchers who pioneered these methods. The book reviews both the theory and practice behind these spectroscopic tools and discusses the scientific discoveries uncovered by these techniques. It begins with a chapter on the use of optical resonators for frequency stabilization of lasers, which is followed by in-depth chapters discussing cavity ring-down spectroscopy, frequency-modulated, cavity-enhanced spectroscopy, intracavity spectr

  5. Tuned optical cavity magnetometer

    Science.gov (United States)

    Okandan, Murat; Schwindt, Peter

    2010-11-02

    An atomic magnetometer is disclosed which utilizes an optical cavity formed from a grating and a mirror, with a vapor cell containing an alkali metal vapor located inside the optical cavity. Lasers are used to magnetically polarize the alkali metal vapor and to probe the vapor and generate a diffracted laser beam which can be used to sense a magnetic field. Electrostatic actuators can be used in the magnetometer for positioning of the mirror, or for modulation thereof. Another optical cavity can also be formed from the mirror and a second grating for sensing, adjusting, or stabilizing the position of the mirror.

  6. Hydroforming of elliptical cavities

    Science.gov (United States)

    Singer, W.; Singer, X.; Jelezov, I.; Kneisel, P.

    2015-02-01

    Activities of the past several years in developing the technique of forming seamless (weldless) cavity cells by hydroforming are summarized. An overview of the technique developed at DESY for the fabrication of single cells and multicells of the TESLA cavity shape is given and the major rf results are presented. The forming is performed by expanding a seamless tube with internal water pressure while simultaneously swaging it axially. Prior to the expansion the tube is necked at the iris area and at the ends. Tube radii and axial displacements are computer controlled during the forming process in accordance with results of finite element method simulations for necking and expansion using the experimentally obtained strain-stress relationship of tube material. In cooperation with industry different methods of niobium seamless tube production have been explored. The most appropriate and successful method is a combination of spinning or deep drawing with flow forming. Several single-cell niobium cavities of the 1.3 GHz TESLA shape were produced by hydroforming. They reached accelerating gradients Eacc up to 35 MV /m after buffered chemical polishing (BCP) and up to 42 MV /m after electropolishing (EP). More recent work concentrated on fabrication and testing of multicell and nine-cell cavities. Several seamless two- and three-cell units were explored. Accelerating gradients Eacc of 30 - 35 MV /m were measured after BCP and Eacc up to 40 MV /m were reached after EP. Nine-cell niobium cavities combining three three-cell units were completed at the company E. Zanon. These cavities reached accelerating gradients of Eacc=30 - 35 MV /m . One cavity is successfully integrated in an XFEL cryomodule and is used in the operation of the FLASH linear accelerator at DESY. Additionally the fabrication of bimetallic single-cell and multicell NbCu cavities by hydroforming was successfully developed. Several NbCu clad single-cell and double-cell cavities of the TESLA shape have been

  7. Hydroforming of elliptical cavities

    Directory of Open Access Journals (Sweden)

    W. Singer

    2015-02-01

    Full Text Available Activities of the past several years in developing the technique of forming seamless (weldless cavity cells by hydroforming are summarized. An overview of the technique developed at DESY for the fabrication of single cells and multicells of the TESLA cavity shape is given and the major rf results are presented. The forming is performed by expanding a seamless tube with internal water pressure while simultaneously swaging it axially. Prior to the expansion the tube is necked at the iris area and at the ends. Tube radii and axial displacements are computer controlled during the forming process in accordance with results of finite element method simulations for necking and expansion using the experimentally obtained strain-stress relationship of tube material. In cooperation with industry different methods of niobium seamless tube production have been explored. The most appropriate and successful method is a combination of spinning or deep drawing with flow forming. Several single-cell niobium cavities of the 1.3 GHz TESLA shape were produced by hydroforming. They reached accelerating gradients E_{acc} up to 35  MV/m after buffered chemical polishing (BCP and up to 42  MV/m after electropolishing (EP. More recent work concentrated on fabrication and testing of multicell and nine-cell cavities. Several seamless two- and three-cell units were explored. Accelerating gradients E_{acc} of 30–35  MV/m were measured after BCP and E_{acc} up to 40  MV/m were reached after EP. Nine-cell niobium cavities combining three three-cell units were completed at the company E. Zanon. These cavities reached accelerating gradients of E_{acc}=30–35  MV/m. One cavity is successfully integrated in an XFEL cryomodule and is used in the operation of the FLASH linear accelerator at DESY. Additionally the fabrication of bimetallic single-cell and multicell NbCu cavities by hydroforming was successfully developed. Several NbCu clad single-cell and

  8. Demonstration of suppressed phonon tunneling losses in phononic bandgap shielded membrane resonators for high-Q optomechanics.

    Science.gov (United States)

    Tsaturyan, Yeghishe; Barg, Andreas; Simonsen, Anders; Villanueva, Luis Guillermo; Schmid, Silvan; Schliesser, Albert; Polzik, Eugene S

    2014-03-24

    Dielectric membranes with exceptional mechanical and optical properties present one of the most promising platforms in quantum opto-mechanics. The performance of stressed silicon nitride nanomembranes as mechanical resonators notoriously depends on how their frame is clamped to the sample mount, which in practice usually necessitates delicate, and difficult-to-reproduce mounting solutions. Here, we demonstrate that a phononic bandgap shield integrated in the membrane's silicon frame eliminates this dependence, by suppressing dissipation through phonon tunneling. We dry-etch the membrane's frame so that it assumes the form of a cm-sized bridge featuring a 1-dimensional periodic pattern, whose phononic density of states is tailored to exhibit one, or several, full band gaps around the membrane's high-Q modes in the MHz-range. We quantify the effectiveness of this phononic bandgap shield by optical interferometry measuring both the suppressed transmission of vibrations, as well as the influence of frame clamping conditions on the membrane modes. We find suppressions up to 40 dB and, for three different realized phononic structures, consistently observe significant suppression of the dependence of the membrane's modes on sample clamping-if the mode's frequency lies in the bandgap. As a result, we achieve membrane mode quality factors of 5 × 10(6) with samples that are tightly bolted to the 8 K-cold finger of a cryostat. Q × f -products of 6 × 10(12) Hz at 300 K and 14 × 10(12) Hz at 8 K are observed, satisfying one of the main requirements for optical cooling of mechanical vibrations to their quantum ground-state.

  9. Controlling silk fibroin microspheres via molecular weight distribution

    International Nuclear Information System (INIS)

    Zeng, Dong-Mei; Pan, Jue-Jing; Wang, Qun; Liu, Xin-Fang; Wang, Hui; Zhang, Ke-Qin

    2015-01-01

    Silk fibroin (SF) microspheres were produced by salting out SF solution via the addition of potassium phosphate buffer solution (K 2 HPO 4 –KH 2 PO 4 ). The morphology, size and polydispersity of SF microspheres were adjusted by changing the molecular weight (MW) distribution and concentration of SF, as well as the ionic strength and pH of the buffer solution. Changing the conditions under which the SF fiber dissolved in the Lithium Boride (LiBr) solution resulted in altering the MW distribution of SF solution. Under optimal salting-out conditions (ionic strength > 0.7 M and pH > 7) and using a smaller and narrower SF MW distribution, SF microspheres with smoother shapes and more uniform sizes were produced. Meanwhile, the size and polydispersity of the microspheres increased when the SF concentration was increased from 0.25 mg/mL to 20 mg/mL. The improved SF microspheres, obtained by altering the distribution of molecular weight, have potential in drug and gene delivery applications. - Highlights: • MW distribution was changed by applying different dissolving methods of SF fiber. • Smaller and narrower MW distribution improves the quality of SF microspheres. • Size and polydispersity of microspheres increase as SF concentration increases. • Improved SF microspheres have potential in drug and gene delivery applications

  10. Toward quantum-limited position measurements using optically levitated microspheres

    International Nuclear Information System (INIS)

    Libbrecht, Kenneth G.; Black, Eric D.

    2004-01-01

    We propose the use of optically levitated microspheres as test masses in experiments aimed at reaching and potentially exceeding the standard quantum limit for position measurements. Optically levitated microspheres have low mass and are essentially free of suspension thermal noise, making them well suited for experimentally testing our understanding of quantum-limited measurements

  11. Toward quantum-limited position measurements using optically levitated microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Libbrecht, Kenneth G.; Black, Eric D

    2004-01-26

    We propose the use of optically levitated microspheres as test masses in experiments aimed at reaching and potentially exceeding the standard quantum limit for position measurements. Optically levitated microspheres have low mass and are essentially free of suspension thermal noise, making them well suited for experimentally testing our understanding of quantum-limited measurements.

  12. Development and evaluation of floating microspheres of curcumin in ...

    African Journals Online (AJOL)

    Purpose: To prepare and evaluate floating microspheres of curcumin for prolonged gastric residence and to study their effect on alloxan-induced diabetic rats. Methods: Floating microsphere were prepared by emulsion-solvent diffusion method, using hydroxylpropyl methylcellulose, chitosan and Eudragit S 100 polymer in ...

  13. Development and Evaluation of Floating Microspheres of Curcumin ...

    African Journals Online (AJOL)

    Purpose: To prepare and evaluate floating microspheres of curcumin for prolonged gastric residence time and increased drug bioavailability. Methods: Floating microsphere were prepared by emulsion solvent diffusion method, using hydroxylpropyl methylcellulose (HPMC), ethyl cellulose (EC), Eudragit S 100 polymer in ...

  14. PLGA and PHBV Microsphere Formulations and Solid-State Characterization

    DEFF Research Database (Denmark)

    Yang, Chiming; Plackett, David; Needham, David

    2009-01-01

    To develop and characterize the solid-state properties of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) microspheres for the localized and controlled release of fusidic acid (FA). The effects of FA loading and polymer composition on the me...... of a DCM-FA-rich phase in the forming microsphere....

  15. Preparation of mesoporous zirconia microspheres as inert matrix

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Ting [State Key Laboratory of New Ceramics and Fine Processing, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China); Wang, Chen; Lv, Jinlong [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China); Liang, Tongxiang, E-mail: txliang@tsinghua.edu.cn [State Key Laboratory of New Ceramics and Fine Processing, Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing, 100084 (China)

    2016-12-01

    Mesoporous zirconia microspheres, with a diameter of 900 μm, were prepared as an inert accelerator driven system (ADS) transmutation element matrix by the sol-gel method. The purpose of mesopores is to improve the adsorption capacity of inert matrix fuel (IMF) for minor actinides. The study indicated that the mesoporous zirconia performance was improved after the microspheres were hydrothermally treated at 150 °C, the specific surface area increased from 28.29 m{sup 2}/g to 61.28 m{sup 2}/g, and hydrothermal treatment avoided the cracking of the microspheres. Pre-decomposition of the organics during the hydrothermal process stabilized the mesoporous structure. The average pore diameter of mesoporous microsphere was 14.3 nm. - Highlights: • Mesoporous zirconia microspheres with a diameter of 900 μm were prepared as ADS transmutation element inert matrix. • The mesoporous performance was improved after the microspheres were hydrothermally treated at 150 °C. • The specific surface area increased from 28.29 m{sup 2}/g to 61.28 m{sup 2}/g. • The hydrothermal treatment could avoid the cracking of the microspheres. • The specific surface area of mesoporous microsphere was 61.28 m{sup 2}/g and the average pore diameter was 14.3 nm.

  16. Antibacterial activity of ciprofloxacin-loaded zein microsphere films

    International Nuclear Information System (INIS)

    Fu Jianxi; Wang Huajie; Zhou Yanqing; Wang Jinye

    2009-01-01

    Our aim was to produce an antibiotic-emitting coating composed of zein microspheres for the prevention of bacterial infection on implanted devices. Ciprofloxacin-loaded zein microspheres were prepared using a phase separation procedure, with particle sizes between 0.5 and 2 μm. Drug encapsulation and drug loading varied with the amount of both zein and ciprofloxacin, and the highest encapsulation efficiency was 8.27% (2 mg/ml ciprofloxacin and 20 mg/ml zein; n = 3). A ciprofloxacin-loaded zein microsphere film (CF-MS film) was generated via solvent evaporation. Continuous drug release from a trypsin-degraded microsphere film was observed for up to 28 days. The liberation of ciprofloxacin from the trypsin-degraded film and the biodegradation of the microsphere film were highly correlated. Proliferation assay of the growth of human umbilical vein endothelial cells (HUVECs) by the MTT method showed that the microsphere film had no toxicity when compared with cells grown on Corning culture plates alone and plates with a zein film alone. Quantification of bacteria adhesion showed that adhesion on the microsphere film is significantly suppressed. In addition, according to the results of bacterial growth tests, ciprofloxacin-loaded microsphere films maintained antibacterial activity for more than 6 days. In contrast, a control medium containing a zein film allowed constant bacterial growth. These results indicate that CF-MS films might be useful as antibacterial films on implanted devices.

  17. Apparatus for manufacturing ceramics microspheres for cementing applications

    NARCIS (Netherlands)

    2012-01-01

    A method and apparatus for manufacturing ceramic microspheres from industrial slag. The micro spheres have a particle size of about 38 microns to about 150 microns. The microspheres are used to create a cement slurry having a density of at least about Illbs/g. The resultant cement slurry may then be

  18. Controlling silk fibroin microspheres via molecular weight distribution

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Dong-Mei; Pan, Jue-Jing; Wang, Qun; Liu, Xin-Fang; Wang, Hui [National Engineering Laboratory for Modern Silk, College for Textile and Clothing Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Zhang, Ke-Qin, E-mail: kqzhang@suda.edu.cn [National Engineering Laboratory for Modern Silk, College for Textile and Clothing Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Research Center of Cooperative Innovation for Functional Organic/Polymer Material Micro/Nanofabrication, Soochow University, Suzhou, Jiangsu 215123 (China)

    2015-05-01

    Silk fibroin (SF) microspheres were produced by salting out SF solution via the addition of potassium phosphate buffer solution (K{sub 2}HPO{sub 4}–KH{sub 2}PO{sub 4}). The morphology, size and polydispersity of SF microspheres were adjusted by changing the molecular weight (MW) distribution and concentration of SF, as well as the ionic strength and pH of the buffer solution. Changing the conditions under which the SF fiber dissolved in the Lithium Boride (LiBr) solution resulted in altering the MW distribution of SF solution. Under optimal salting-out conditions (ionic strength > 0.7 M and pH > 7) and using a smaller and narrower SF MW distribution, SF microspheres with smoother shapes and more uniform sizes were produced. Meanwhile, the size and polydispersity of the microspheres increased when the SF concentration was increased from 0.25 mg/mL to 20 mg/mL. The improved SF microspheres, obtained by altering the distribution of molecular weight, have potential in drug and gene delivery applications. - Highlights: • MW distribution was changed by applying different dissolving methods of SF fiber. • Smaller and narrower MW distribution improves the quality of SF microspheres. • Size and polydispersity of microspheres increase as SF concentration increases. • Improved SF microspheres have potential in drug and gene delivery applications.

  19. Porous-wall hollow glass microspheres as carriers for biomolecules

    Science.gov (United States)

    Li, Shuyi; Dynan, William S; Wicks, George; Serkiz, Steven

    2013-09-17

    The present invention includes compositions of porous-wall hollow glass microspheres and one or more biomolecules, wherein the one or more biomolecules are positioned within a void location within the hollow glass microsphere, and the use of such compositions for the diagnostic and/or therapeutic delivery of biomolecules.

  20. Antibacterial activity of ciprofloxacin-loaded zein microsphere films

    Energy Technology Data Exchange (ETDEWEB)

    Fu Jianxi [Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032 (China); Henan Normal University, 46 East Construction Road, Xinxiang, Henan 453007 (China); Wang Huajie [College of Life Science and Biotechnology, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China); Zhou Yanqing [Henan Normal University, 46 East Construction Road, Xinxiang, Henan 453007 (China); Wang Jinye, E-mail: jywang@mail.sioc.ac.cn [Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032 (China); College of Life Science and Biotechnology, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China)

    2009-05-05

    Our aim was to produce an antibiotic-emitting coating composed of zein microspheres for the prevention of bacterial infection on implanted devices. Ciprofloxacin-loaded zein microspheres were prepared using a phase separation procedure, with particle sizes between 0.5 and 2 {mu}m. Drug encapsulation and drug loading varied with the amount of both zein and ciprofloxacin, and the highest encapsulation efficiency was 8.27% (2 mg/ml ciprofloxacin and 20 mg/ml zein; n = 3). A ciprofloxacin-loaded zein microsphere film (CF-MS film) was generated via solvent evaporation. Continuous drug release from a trypsin-degraded microsphere film was observed for up to 28 days. The liberation of ciprofloxacin from the trypsin-degraded film and the biodegradation of the microsphere film were highly correlated. Proliferation assay of the growth of human umbilical vein endothelial cells (HUVECs) by the MTT method showed that the microsphere film had no toxicity when compared with cells grown on Corning culture plates alone and plates with a zein film alone. Quantification of bacteria adhesion showed that adhesion on the microsphere film is significantly suppressed. In addition, according to the results of bacterial growth tests, ciprofloxacin-loaded microsphere films maintained antibacterial activity for more than 6 days. In contrast, a control medium containing a zein film allowed constant bacterial growth. These results indicate that CF-MS films might be useful as antibacterial films on implanted devices.

  1. Formulation and Evaluation of Microspheres Based on Gelatin ...

    African Journals Online (AJOL)

    Formulation and Evaluation of Microspheres Based on Gelatin-Mucin Admixtures for the Rectal Delivery of Cefuroxime Sodium. K C Ofokansi, M U Adikwu. Abstract. Purpose: Swellable microspheres based on polymers or their admixtures are frequently employed as drug delivery systems to achieve a controlled release ...

  2. Microspheres with Ultrahigh Holmium Content for Radioablation of Malignancies

    NARCIS (Netherlands)

    Bult, W.; Seevinck, P.R.; Krijger, G.C.; Visser, T.; Kroon-Batenburg, L.M.J.; Bakker, C.J.G.; Hennink, W.E.; van het Schip, A.D.; Nijsen, J.F.W.

    2009-01-01

    The aim of this study was to develop microspheres with an ultra high holmium content which can be neutron activated for radioablation of malignancies. These microspheres are proposed to be delivered selectively through either intratumoral injections into solid tumors or administered via an

  3. Microspheres with ultrahigh holmium content for radioablation of malignancies

    NARCIS (Netherlands)

    Bult, W; Seevinck, P R; Krijger, G C; Visser, T; Kroon-Batenburg, L M J; Bakker, C J G; Hennink, W E; van het Schip, A D; Nijsen, J F W

    PURPOSE: The aim of this study was to develop microspheres with an ultra high holmium content which can be neutron activated for radioablation of malignancies. These microspheres are proposed to be delivered selectively through either intratumoral injections into solid tumors or administered via an

  4. Microspheres with Ultrahigh Holmium Content for Radioablation of Malignancies

    NARCIS (Netherlands)

    Bult, W.; Seevinck, P.R.; Krijger, G.C.; Visser, T.; Kroon-Batenburg, L.M.J.; Bakker, C.J.G.; Hennink, W.E.; Van het Schip, A.D.; Nijsen, J.F.W.

    Purpose The aim of this study was to develop microspheres with an ultra high holmium content which can be neutron activated for radioablation of malignancies. These microspheres are proposed to be delivered selectively through either intratumoral injections into solid tumors or administered via an

  5. Microspheres labelled with short-lived isotopes: Development and application for tumors treatment (Experimental study)

    International Nuclear Information System (INIS)

    Drozdovsky, B.Y.; Rosiev, R.A.; Goncharova, A.Y.; Skvortsov, V.G.; Petriev, V.M.; Grigoriev, A.N.; Schischkanov, N.G.

    1997-01-01

    Analysis of the conducted studies strongly suggests the possibility of usage of the domestic protein microspheres as a vehicle for radionuclide. The neutron-activating method of RPP production enables to utilize a broad spectrum of short-living isotopes that can be delivered into the target organ and anchored there for a long time. Good treatment results were obtained in case of the experimentally induced rheumatoid arthritis in rats after intraarticular loading of 165 Dy-hMSA. Mathematical calculations show that homogeneous distribution of RPP in human articulation cavity with the square of 100 cm 2 can be achieved when the quantity of administered particles exceeds 3000. On the example of 165 Dy-hMSA energy characteristic distribution we demonstrated that the absorbed dose for damaged cells at 2mm distance from the radioactive source is 7 times less than the one for a sphere of 2mm diameter. Analysis of dosimetric data in case of intratumoral loading of 165 Dy-hMSA also point out the necessity of the absorbed dose calculation methods taking into account the distance from the source and possible heterogeneity of RPP distribution inside the tumor to be employed. The prolonged RPP detention in the target causing no essential morphological and functional changes was achieved by embolization on the level of septal and interlobular arteries and of efferent arterioles in the animal's renal. The uniformity of microsphere distribution in the organ and their accumulation in tumors depends on the number of particles being administered. Investigations carried out suggest the efficacy of radionuclide therapy application for treatment of oncological and heavy somatic diseases. They also indicate the necessity of further investigations aimed to optimize the usage of microspheres as a radionuclide carrier usage and to work out the criteria of dosimetric planning

  6. Microspheres labelled with short-lived isotopes: Development and application for tumors treatment (Experimental study)

    Energy Technology Data Exchange (ETDEWEB)

    Drozdovsky, B.Y.; Rosiev, R.A.; Goncharova, A.Y.; Skvortsov, V.G.; Petriev, V.M.; Grigoriev, A.N.; Schischkanov, N.G. [Medical Radiological Research Centre RAMS, Kaluga Region, (Russian Federation)

    1997-10-01

    Analysis of the conducted studies strongly suggests the possibility of usage of the domestic protein microspheres as a vehicle for radionuclide. The neutron-activating method of RPP production enables to utilize a broad spectrum of short-living isotopes that can be delivered into the target organ and anchored there for a long time. Good treatment results were obtained in case of the experimentally induced rheumatoid arthritis in rats after intraarticular loading of {sup 165}Dy-hMSA. Mathematical calculations show that homogeneous distribution of RPP in human articulation cavity with the square of 100 cm{sup 2} can be achieved when the quantity of administered particles exceeds 3000. On the example of {sup 165}Dy-hMSA energy characteristic distribution we demonstrated that the absorbed dose for damaged cells at 2mm distance from the radioactive source is 7 times less than the one for a sphere of 2mm diameter. Analysis of dosimetric data in case of intratumoral loading of {sup 165}Dy-hMSA also point out the necessity of the absorbed dose calculation methods taking into account the distance from the source and possible heterogeneity of RPP distribution inside the tumor to be employed. The prolonged RPP detention in the target causing no essential morphological and functional changes was achieved by embolization on the level of septal and interlobular arteries and of efferent arterioles in the animal`s renal. The uniformity of microsphere distribution in the organ and their accumulation in tumors depends on the number of particles being administered. Investigations carried out suggest the efficacy of radionuclide therapy application for treatment of oncological and heavy somatic diseases. They also indicate the necessity of further investigations aimed to optimize the usage of microspheres as a radionuclide carrier usage and to work out the criteria of dosimetric planning 25 refs.

  7. Optimization of sustained release aceclofenac microspheres using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, Rameshwar K.; Naik, Jitendra B., E-mail: jitunaik@gmail.com

    2015-03-01

    Polymeric microspheres containing aceclofenac were prepared by single emulsion (oil-in-water) solvent evaporation method using response surface methodology (RSM). Microspheres were prepared by changing formulation variables such as the amount of Eudragit® RS100 and the amount of polyvinyl alcohol (PVA) by statistical experimental design in order to enhance the encapsulation efficiency (E.E.) of the microspheres. The resultant microspheres were evaluated for their size, morphology, E.E., and in vitro drug release. The amount of Eudragit® RS100 and the amount of PVA were found to be significant factors respectively for determining the E.E. of the microspheres. A linear mathematical model equation fitted to the data was used to predict the E.E. in the optimal region. Optimized formulation of microspheres was prepared using optimal process variables setting in order to evaluate the optimization capability of the models generated according to IV-optimal design. The microspheres showed high E.E. (74.14 ± 0.015% to 85.34 ± 0.011%) and suitably sustained drug release (minimum; 40% to 60%; maximum) over a period of 12 h. The optimized microspheres formulation showed E.E. of 84.87 ± 0.005 with small error value (1.39). The low magnitudes of error and the significant value of R{sup 2} in the present investigation prove the high prognostic ability of the design. The absence of interactions between drug and polymers was confirmed by Fourier transform infrared (FTIR) spectroscopy. Differential scanning calorimetry (DSC) and X-ray powder diffractometry (XRPD) revealed the dispersion of drug within microspheres formulation. The microspheres were found to be discrete, spherical with smooth surface. The results demonstrate that these microspheres could be promising delivery system to sustain the drug release and improve the E.E. thus prolong drug action and achieve the highest healing effect with minimal gastrointestinal side effects. - Highlights: • Aceclofenac microspheres

  8. SPS accelerating cavity

    CERN Multimedia

    CERN PhotoLab

    1976-01-01

    The SPS started up with 2 accelerating cavities (each consisting of 5 tank sections) in LSS3. They have a 200 MHz travelling wave structure (see 7411032 and 7802190) and 750 kW of power is fed to each of the cavities from a 1 MW tetrode power amplifier, located in a surface building above, via a coaxial transmission line. Clemens Zettler, builder of the SPS RF system, is standing at the side of one of the cavities. In 1978 and 1979 another 2 cavities were added and entered service in 1980. These were part of the intensity improvement programme and served well for the new role of the SPS as proton-antiproton collider. See also 7411032, 8011289, 8104138, 8302397.

  9. Dental Sealants Prevent Cavities

    Science.gov (United States)

    ... Digital Press Kit Read the MMWR Science Clips Dental Sealants Prevent Cavities Effective protection for children Language: ... more use of sealants and reimbursement of services. Dental care providers can Apply sealants to children at ...

  10. Statistical electromagnetics: Complex cavities

    NARCIS (Netherlands)

    Naus, H.W.L.

    2008-01-01

    A selection of the literature on the statistical description of electromagnetic fields and complex cavities is concisely reviewed. Some essential concepts, for example, the application of the central limit theorem and the maximum entropy principle, are scrutinized. Implicit assumptions, biased

  11. accelerating cavity from LEP

    CERN Multimedia

    This is an accelerating cavity from LEP, with a layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities are now used in LEP to double the energy of the particle beams.

  12. Preparation and Characterization of Fluorescent SiO2 Microspheres

    Science.gov (United States)

    Xu, Cui; Zhang, Hao; Guan, Ruifang

    2018-01-01

    Fluorescent compound without typical fluorophores was synthesized with citric acid (CA) and aminopropyltriethoxysilane (APTS) firstly, and then it was grafted to the surface of the prepared SiO2 microspheres by chemical reaction. The fluorescent SiO2 microspheres with good fluorescent properties were obtained by optimizing the reaction conditions. And the morphology and structure of the fluorescent SiO2 microspheres have been characterized by scanning electron microscopy (SEM) and fourier transform infrared (FTIR) spectroscopy. The results showed that the preparation of fluorescent SiO2 microspheres have good monodispersity and narrow particle size distribution. Moreover, the fluorescent SiO2 microspheres can be applied to detect Fe3+ in aqueous solution, prepare fluorescent SiO2 rubber, and have potential to be applied in the fluorescent labeling and fingerprint appearing technique fields.

  13. Study on the Degradation of Polylactide Microsphere In Vitro

    Institute of Scientific and Technical Information of China (English)

    HeYing; WeiShuli

    2001-01-01

    This report concentrated on the rules and mechanism of the degradation of polylactide and the microspheres. The rate of degradation was assessed with five methods: observation of microsphere surface morphology by SEM, determination of the weight loss of the microspheres, determination of the molecular mass of the polymers by GPC, determination of pH and determination of the contents of lactic acid by UV spectrophotometry. The degradation of polylactide microspheres showed two-phase characteristics. At the early stage of the degradation, the high molecular mass polymers were cleaved into lower molecular mass fractions and at the late stage, there was a period of erosion and weight loss of the microspheres. The degradation was much slower for polymers with a higher molecular mass. The polylactide degradation showed good regularity.

  14. Hollow porous-wall glass microspheres for hydrogen storage

    Science.gov (United States)

    Heung, Leung K.; Schumacher, Ray F.; Wicks, George G.

    2010-02-23

    A porous wall hollow glass microsphere is provided having a diameter range of between 1 to 200 microns, a density of between 1.0 to 2.0 gm/cc, a porous-wall structure having wall openings defining an average pore size of between 10 to 1000 angstroms, and which contains therein a hydrogen storage material. The porous-wall structure facilitates the introduction of a hydrogen storage material into the interior of the porous wall hollow glass microsphere. In this manner, the resulting hollow glass microsphere can provide a membrane for the selective transport of hydrogen through the porous walls of the microsphere, the small pore size preventing gaseous or liquid contaminants from entering the interior of the hollow glass microsphere.

  15. Hybrid vertical cavity laser

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    2010-01-01

    A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide.......A new hybrid vertical cavity laser structure for silicon photonics is suggested and numerically investigated. It incorporates a silicon subwavelength grating as a mirror and a lateral output coupler to a silicon ridge waveguide....

  16. The Superconducting TESLA Cavities

    CERN Document Server

    Aune, B.; Bloess, D.; Bonin, B.; Bosotti, A.; Champion, M.; Crawford, C.; Deppe, G.; Dwersteg, B.; Edwards, D.A.; Edwards, H.T.; Ferrario, M.; Fouaidy, M.; Gall, P-D.; Gamp, A.; Gössel, A.; Graber, J.; Hubert, D.; Hüning, M.; Juillard, M.; Junquera, T.; Kaiser, H.; Kreps, G.; Kuchnir, M.; Lange, R.; Leenen, M.; Liepe, M.; Lilje, L.; Matheisen, A.; Möller, W-D.; Mosnier, A.; Padamsee, H.; Pagani, C.; Pekeler, M.; Peters, H-B.; Peters, O.; Proch, D.; Rehlich, K.; Reschke, D.; Safa, H.; Schilcher, T.; Schmüser, P.; Sekutowicz, J.; Simrock, S.; Singer, W.; Tigner, M.; Trines, D.; Twarowski, K.; Weichert, G.; Weisend, J.; Wojtkiewicz, J.; Wolff, S.; Zapfe, K.

    2000-01-01

    The conceptional design of the proposed linear electron-positron colliderTESLA is based on 9-cell 1.3 GHz superconducting niobium cavities with anaccelerating gradient of Eacc >= 25 MV/m at a quality factor Q0 > 5E+9. Thedesign goal for the cavities of the TESLA Test Facility (TTF) linac was set tothe more moderate value of Eacc >= 15 MV/m. In a first series of 27industrially produced TTF cavities the average gradient at Q0 = 5E+9 wasmeasured to be 20.1 +- 6.2 MV/m, excluding a few cavities suffering fromserious fabrication or material defects. In the second production of 24 TTFcavities additional quality control measures were introduced, in particular aneddy-current scan to eliminate niobium sheets with foreign material inclusionsand stringent prescriptions for carrying out the electron-beam welds. Theaverage gradient of these cavities at Q0 = 5E+9 amounts to 25.0 +- 3.2 MV/mwith the exception of one cavity suffering from a weld defect. Hence only amoderate improvement in production and preparation technique...

  17. Uniform Pore Structure of Mesoporous Silica Microspheres by Using Di(2-ethylhexyl)phosphoric Acid

    International Nuclear Information System (INIS)

    Kim, Jong Yun; Yoon, Suk Bon; Park, Yong Joon; Jee, Kwang Yong

    2007-01-01

    Spherical morphology has been quite attractive in many special applications, such as display materials offering higher packing densities and lower light scattering for better performances in terms of both brightness and resolution, biosensors utilizing microspheres as an ideal dielectric cavities with high quality factors in optical domain, and standard reference particles for nuclear track analysis utilizing their simple well-defined geometry. There are tremendously a wide variety of studies focused on colloidal spheres of 1 nm - 1,000 nm in diameter although the colloidal dimension can be extended further to 100 μm. Some reports have described the sol-gel surfactant template synthesis of mesoporous silica spheres larger than 100 μm. It is necessary for us to prepare the intermediate 10 - 100 μm-sized silica microspheres for the single particle manipulation by using optical microscope, rather than electron microscope, in a microanalytical technique such as thermal ionization mass spectrometry, secondary ionization mass spectrometry, and laser ionization mass spectrometry

  18. Mesoporous metal oxide microsphere electrode compositions and their methods of making

    Science.gov (United States)

    Parans Paranthaman, Mariappan; Bi, Zhonghe; Bridges, Craig A.; Brown, Gilbert M.

    2017-04-11

    Compositions and methods of making are provided for treated mesoporous metal oxide microspheres electrodes. The compositions include microspheres with an average diameter between about 200 nanometers and about 10 micrometers and mesopores on the surface and interior of the microspheres. The methods of making include forming a mesoporous metal oxide microsphere composition and treating the mesoporous metal oxide microspheres by at least annealing in a reducing atmosphere, doping with an aliovalent element, and coating with a coating composition.

  19. Long pulse microsphere experiments at 3 TW

    International Nuclear Information System (INIS)

    Boyle, M.J.; Attwood, D.T.; Brooks, K.M.

    1977-01-01

    Previous 1.06 μm laser implosion experiments have explored the parameter space associated with microsphere targets of typically less than 100 psec. Exploding pusher experiments have now been performed using long pulses (100 to 200 psec FWHM), and large diameter (100 to 150 μm) targets on the 3 TW Argus laser facility. Absorption, transport, implosion and neutron and α yield characteristics are discussed and compared with earlier short pulse results. The observed neutron yields are discussed in light of the temporal mismatch between the absorption and implosion time scales imposed by the large diameter, long pulse conditions

  20. Understanding Quality Factor Degradation in Superconducting Niobium Cavities at Low Microwave Field Amplitudes

    Science.gov (United States)

    Romanenko, A.; Schuster, D. I.

    2017-12-01

    In niobium superconducting radio frequency (SRF) cavities for particle acceleration, a decrease of the quality factor at lower fields—a so-called low field Q slope or LFQS—has been a long-standing unexplained effect. By extending the high Q measurement techniques to ultralow fields, we discover two previously unknown features of the effect: (i) saturation at rf fields lower than Eacc˜0.1 MV /m ; (ii) strong degradation enhancement by growing thicker niobium pentoxide. Our findings suggest that the LFQS may be caused by the two level systems in the natural niobium oxide on the inner cavity surface, thereby identifying a new source of residual resistance and providing guidance for potential nonaccelerator low-field applications of SRF cavities.

  1. Correlated motion of two atoms trapped in a single-mode cavity field

    International Nuclear Information System (INIS)

    Asboth, Janos K.; Domokos, Peter; Ritsch, Helmut

    2004-01-01

    We study the motion of two atoms trapped at distant positions in the field of a driven standing-wave high-Q optical resonator. Even without any direct atom-atom interaction the atoms are coupled through their position dependent influence on the intracavity field. For sufficiently good trapping and low cavity losses the atomic motion becomes significantly correlated and the two particles oscillate in their wells preferentially with a 90 deg. relative phase shift. The onset of correlations seriously limits cavity cooling efficiency, raising the achievable temperature to the Doppler limit. The physical origin of the correlation can be traced back to a cavity mediated crossfriction, i.e., a friction force on one particle depending on the velocity of the second particle. Choosing appropriate operating conditions allows for engineering these long range correlations. In addition this cross-friction effect can provide a basis for sympathetic cooling of distant trapped clouds

  2. Probing different regimes of strong field light-matter interaction with semiconductor quantum dots and few cavity photons

    Science.gov (United States)

    Hargart, F.; Roy-Choudhury, K.; John, T.; Portalupi, S. L.; Schneider, C.; Höfling, S.; Kamp, M.; Hughes, S.; Michler, P.

    2016-12-01

    In this work we present an extensive experimental and theoretical investigation of different regimes of strong field light-matter interaction for cavity-driven quantum dot (QD) cavity systems. The electric field enhancement inside a high-Q micropillar cavity facilitates exceptionally strong interaction with few cavity photons, enabling the simultaneous investigation for a wide range of QD-laser detuning. In case of a resonant drive, the formation of dressed states and a Mollow triplet sideband splitting of up to 45 μeV is measured for a mean cavity photon number ≤slant 1. In the asymptotic limit of the linear AC Stark effect we systematically investigate the power and detuning dependence of more than 400 QDs. Some QD-cavity systems exhibit an unexpected anomalous Stark shift, which can be explained by an extended dressed 4-level QD model. We provide a detailed analysis of the QD-cavity systems properties enabling this novel effect. The experimental results are successfully reproduced using a polaron master equation approach for the QD-cavity system, which includes the driving laser field, exciton-cavity and exciton-phonon interactions.

  3. Insulin delivery through nasal route using thiolated microspheres.

    Science.gov (United States)

    Nema, Tarang; Jain, Ashish; Jain, Aviral; Shilpi, Satish; Gulbake, Arvind; Hurkat, Pooja; Jain, Sanjay K

    2013-01-01

    The aim of the present study was to investigate the potential of developed thiolated microspheres for insulin delivery through nasal route. In the present study, cysteine was immobilized on carbopol using EDAC. A total of 269.93 µmol free thiol groups per gram polymer were determined. The prepared nonthiolated and thiolated microspheres were studied for particle shape, size, drug content, swellability, mucoadhesion and in vitro insulin release. The thiolated microspheres exhibited higher mucoadhesion due to formation of covalent bonds via disulfide bridges with the mucus gel layer. Drug permeation through goat nasal mucosa of nonthiolated and thiolated microspheres were found as 52.62 ± 2.4% and 78.85 ± 3.1% in 6 h, respectively. Thiolated microspheres bearing insulin showed better reduction in blood glucose level (BGL) in comparison to nonthiolated microspheres as 31.23 ± 2.12% and 75.25 ± 0.93% blood glucose of initial BGL were observed at 6 h after nasal delivery of thiolated and nonthiolated microspheres in streptozotocin-induced diabetic rabbits.

  4. Magnetic poly(glycidyl methacrylate) microspheres for protein capture.

    Science.gov (United States)

    Koubková, Jana; Müller, Petr; Hlídková, Helena; Plichta, Zdeněk; Proks, Vladimír; Vojtěšek, Bořivoj; Horák, Daniel

    2014-09-25

    The efficient isolation and concentration of protein antigens from complex biological samples is a critical step in several analytical methods, such as mass spectrometry, flow cytometry and immunochemistry. These techniques take advantage of magnetic microspheres as immunosorbents. The focus of this study was on the development of new superparamagnetic polymer microspheres for the specific isolation of the tumor suppressor protein p53. Monodisperse macroporous poly(glycidyl methacrylate) (PGMA) microspheres measuring approximately 5 μm and containing carboxyl groups were prepared by multistep swelling polymerization of glycidyl methacrylate (GMA), 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA) and ethylene dimethylacrylate (EDMA) as a crosslinker in the presence of cyclohexyl acetate as a porogen. To render the microspheres magnetic, iron oxide was precipitated within their pores; the Fe content in the particles received ∼18 wt%. Nonspecific interactions between the magnetic particles and biological media were minimized by coating the microspheres with poly(ethylene glycol) (PEG) terminated by carboxyl groups. The carboxyl groups of the magnetic PGMA microspheres were conjugated with primary amino groups of mouse monoclonal DO-1 antibody using conventional carbodiimide chemistry. The efficiency of protein p53 capture and the degree of nonspecific adsorption on neat and PEG-coated magnetic microspheres were determined by western blot analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Measurement of thermal diffusivity of depleted uranium metal microspheres

    Science.gov (United States)

    Humrickhouse-Helmreich, Carissa J.; Corbin, Rob; McDeavitt, Sean M.

    2014-03-01

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time-temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal.

  6. Measurement of thermal diffusivity of depleted uranium metal microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Humrickhouse-Helmreich, Carissa J., E-mail: carissahelmreich@tamu.edu [Texas A and M University, Department of Nuclear Engineering, 337 Zachry Engineering Center, 3133 TAMU, College Station, TX 77843 (United States); Corbin, Rob, E-mail: rcorbin@terrapower.com [TerraPower, LLC, 330 120th Ave NE, Suite 100, Bellevue, WA 98005 (United States); McDeavitt, Sean M., E-mail: mcdeavitt@tamu.edu [Texas A and M University, Department of Nuclear Engineering, 337 Zachry Engineering Center, 3133 TAMU, College Station, TX 77843 (United States)

    2014-03-15

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time–temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal.

  7. Preparation of nano-hydroxyapatite/poly(l-lactide) biocomposite microspheres

    International Nuclear Information System (INIS)

    Qiu Xueyu; Han Yadong; Zhuang Xiuli; Chen Xuesi; Li Yuesheng; Jing Xiabin

    2007-01-01

    Nano-hydroxyapatite (HA)/poly(l-lactide) (PLLA) composite microspheres with relatively uniform size distribution were prepared by a solid-in-oil-in-water (s/o/w) emusion solvent evaporation method. The encapsulation of the HA nanopaticles in microshperes was significantly improved by grafting PLLA on the surface of the HA nanoparticles (p-HA) during emulsion process. This procedure gave a possibility to obtain p-HA/PLLA composite microspheres with uniform morphology and the encapsulated p-HA nanoparticle loading reached up to 40 wt% (33 wt% of pure HA) in the p-HA/PLLA composite microspheres. The microstructure of composite microspheres from core-shell to single phase changed with the variation of p-HA to PLLA ratios. p-HA/PLLA composite microspheres with the diameter range of 2-3 μm were obtained. The entrapment efficiency of p-HA in microspheres could high up to 90 wt% and that of HA was only 13 wt%. Surface and bulk characterizations of the composite microspheres were performed by measurements such as wide angle X-ray diffraction (WAXD), thermal gravimetric analysis (TGA), environmental scanning electron microscope (ESEM) and transmission electron microscopy (TEM)

  8. Current knowledge on biodegradable microspheres in drug delivery.

    Science.gov (United States)

    Prajapati, Vipul D; Jani, Girish K; Kapadia, Jinita R

    2015-08-01

    Biodegradable microspheres have gained popularity for delivering a wide variety of molecules via various routes. These types of products have been prepared using various natural and synthetic biodegradable polymers through suitable techniques for desired delivery of various challenging molecules. Selection of biodegradable polymers and technique play a key role in desired drug delivery. This review describes an overview of the fundamental knowledge and status of biodegradable microspheres in effective delivery of various molecules via desired routes with consideration of outlines of various compendial and non-compendial biodegradable polymers, formulation techniques and release mechanism of microspheres, patents and commercial biodegradable microspheres. There are various advantages of using biodegradable polymers including promise of development with different types of molecules. Biocompatibility, low dosage and reduced side effects are some reasons why usage biodegradable microspheres have gained in popularity. Selection of biodegradable polymers and formulation techniques to create microspheres is the biggest challenge in research. In the near future, biodegradable microspheres will become the eco-friendly product for drug delivery of various genes, hormones, proteins and peptides at specific site of body for desired periods of time.

  9. Measurement of thermal diffusivity of depleted uranium metal microspheres

    International Nuclear Information System (INIS)

    Humrickhouse-Helmreich, Carissa J.; Corbin, Rob; McDeavitt, Sean M.

    2014-01-01

    The high void space of nuclear fuels composed of homogeneous uranium metal microspheres may allow them to achieve ultra-high burnup by accommodating fuel swelling and reducing fuel/cladding interactions; however, the relatively low thermal conductivity of microsphere nuclear fuels may limit their application. To support the development of microsphere nuclear fuels, an apparatus was designed in a glovebox and used to measure the apparent thermal diffusivity of a packed bed of depleted uranium (DU) microspheres with argon fill in the void spaces. The developed Crucible Heater Test Assembly (CHTA) recorded radial temperature changes due to an initial heat pulse from a central thin-diameter cartridge heater. Using thermocouple positions and time–temperature data, the apparent thermal diffusivity was calculated. The thermal conductivity of the DU microspheres was calculated based on the thermal diffusivity from the CHTA, known material densities and specific heat capacities, and an assumed 70% packing density based on prior measurements. Results indicate that DU metal microspheres have very low thermal conductivity, relative to solid uranium metal, and rapidly form an oxidation layer even in a low oxygen environment. At 500 °C, the thermal conductivity of the DU metal microsphere bed was 0.431 ± 0.0560 W/m-K compared to the literature value of approximately 32 W/m-K for solid uranium metal

  10. Nanomechanics of biocompatible hollow thin-shell polymer microspheres.

    Science.gov (United States)

    Glynos, Emmanouil; Koutsos, Vasileios; McDicken, W Norman; Moran, Carmel M; Pye, Stephen D; Ross, James A; Sboros, Vassilis

    2009-07-07

    The nanomechanical properties of biocompatible thin-shell hollow polymer microspheres with approximately constant ratio of shell thickness to microsphere diameter were measured by nanocompression tests in aqueous conditions. These microspheres encapsulate an inert gas and are used as ultrasound contrast agents by releasing free microbubbles in the presence of an ultrasound field as a result of free gas leakage from the shell. The tests were performed using an atomic force microscope (AFM) employing the force-distance curve technique. An optical microscope, on which the AFM was mounted, was used to guide the positioning of tipless cantilevers on top of individual microspheres. We performed a systematic study using several cantilevers with spring constants varying from 0.08 to 2.3 N/m on a population of microspheres with diameters from about 2 to 6 microm. The use of several cantilevers with various spring constants allowed a systematic study of the mechanical properties of the microsphere thin shell at different regimes of force and deformation. Using thin-shell mechanics theory for small deformations, the Young's modulus of the thin wall material was estimated and was shown to exhibit a strong size effect: it increased as the shell became thinner. The Young's modulus of thicker microsphere shells converged to the expected value for the macroscopic bulk material. For high applied forces, the force-deformation profiles showed a reversible and/or irreversible nonlinear behavior including "steps" and "jumps" which were attributed to mechanical instabilities such as buckling events.

  11. Video Toroid Cavity Imager

    Energy Technology Data Exchange (ETDEWEB)

    Gerald, Rex E. II; Sanchez, Jairo; Rathke, Jerome W.

    2004-08-10

    A video toroid cavity imager for in situ measurement of electrochemical properties of an electrolytic material sample includes a cylindrical toroid cavity resonator containing the sample and employs NMR and video imaging for providing high-resolution spectral and visual information of molecular characteristics of the sample on a real-time basis. A large magnetic field is applied to the sample under controlled temperature and pressure conditions to simultaneously provide NMR spectroscopy and video imaging capabilities for investigating electrochemical transformations of materials or the evolution of long-range molecular aggregation during cooling of hydrocarbon melts. The video toroid cavity imager includes a miniature commercial video camera with an adjustable lens, a modified compression coin cell imager with a fiat circular principal detector element, and a sample mounted on a transparent circular glass disk, and provides NMR information as well as a video image of a sample, such as a polymer film, with micrometer resolution.

  12. Metasurface external cavity laser

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Luyao, E-mail: luyaoxu.ee@ucla.edu; Curwen, Christopher A.; Williams, Benjamin S. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); California NanoSystems Institute, University of California, Los Angeles, California 90095 (United States); Hon, Philip W. C.; Itoh, Tatsuo [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Chen, Qi-Sheng [Northrop Grumman Aerospace Systems, Redondo Beach, California 90278 (United States)

    2015-11-30

    A vertical-external-cavity surface-emitting-laser is demonstrated in the terahertz range, which is based upon an amplifying metasurface reflector composed of a sub-wavelength array of antenna-coupled quantum-cascade sub-cavities. Lasing is possible when the metasurface reflector is placed into a low-loss external cavity such that the external cavity—not the sub-cavities—determines the beam properties. A near-Gaussian beam of 4.3° × 5.1° divergence is observed and an output power level >5 mW is achieved. The polarized response of the metasurface allows the use of a wire-grid polarizer as an output coupler that is continuously tunable.

  13. Brownian dynamics simulations of insulin microspheres formation

    Science.gov (United States)

    Li, Wei; Chakrabarti, Amit; Gunton, James

    2010-03-01

    Recent experiments have indicated a novel, aqueous process of microsphere insulin fabrication based on controlled phase separation of protein from water-soluble polymers. We investigate the insulin microsphere crystal formation from insulin-PEG-water systems via 3D Brownian Dynamics simulations. We use the two component Asakura-Oosawa model to simulate the kinetics of this colloid polymer mixture. We first perform a deep quench below the liquid-crystal boundary that leads to fractal formation. We next heat the system to obtain a break-up of the fractal clusters and subsequently cool the system to obtain a spherical aggregation of droplets with a relatively narrow size distribution. We analyze the structure factor S(q) to identify the cluster dimension. S(q) crosses over from a power law q dependence of 1.8 (in agreement with DLCA) to 4 as q increases, which shows the evolution from fractal to spherical clusters. By studying the bond-order parameters, we find the phase transition from liquid-like droplets to crystals which exhibit local HCP and FCC order. This work is supported by grants from the NSF and Mathers Foundation.

  14. Thyroid artery embolization with microspheres for hyperthyroidism

    International Nuclear Information System (INIS)

    Du Yahui; Zhong Chenfu; Chen Weijun; Zhang Ying; Luo Jun; Li Xiaoguang; Cao Junjie; Gan Changli; Cao Junjie; Gan Changli

    2006-01-01

    Objective: To evaluate the method and efficacy of thyroid artery embolization as a new therapy for hyperthyroidism. Methods: Thirteen patients with hyperthyroidism underwent selective thyroid artery embolization. Totally 25 thyroid arteries were embolized with microspheres. The indications for this therapy were as followings: 1) To give hyperthyroid patients having an alternative for surgical and 131 I treatment, and 2) To provide a new method for those clinically being difficult to get control with medicine. Results: Serum level of thyroid hormones dropped significantly[T3 from 2.84-9.0 ng/ml to 0.8-2.2 ng/ml, T4 from 162.9-277.2 ng/ml to 50-126 ng/ml] and symptoms of hyperthyroidism were under control in 12 patients within 1 month after the embolization. One patient remained no change 1 month later and refused to be embolized again. The symptoms of twelve patients were effectively controlled through low dose antithyroid medication for more than 6 months follow up with no serious complications. Conclusion: Thyroid artery embolization with microspheres is an effective alternative for surgical and 131 I treatment of hyperthyroidism. (authors)

  15. Preparation and properties of polyvinyl alcohol microspheres

    International Nuclear Information System (INIS)

    Campbell, J.H.; Grens, J.Z.; Poco, J.F.; Ives, B.H.

    1986-06-01

    Polyvinyl alcohol (PVA) microspheres, having a size range of ∼150- to 250-μm diameter with 1- to 5-μm wall thickness, have been fabricated using a solution droplet technique. The spheres were developed for possible use on the Lawrence Livermore National Laboratory (LLNL) Inertial Confinement Fusion (ICF) Program. PVA, a polymer chosen based on earlier survey work carried out at KMS Fusion, Inc., has good strength, low hydrogen permeability, is optically transparent, and water soluble. The latter property makes it safe and easy to use in our droplet generator system. A unique dual-orifice droplet generator was used to prepare the spheres. The droplet generator operating conditions and the column processing parameters were chosen using results from our 1-D model calculations as a guide. The polymer microsphere model is an extension of the model we developed to support the glass sphere production. After preparation, the spheres were physically characterized for surface quality, sphericity, wall thickness (and uniformity), and size. We also determined the buckling pressure for both uncoated and CH-coated spheres. Radiation stability to beta decay (from tritium) was evaluated by exposing the spheres to a 7-keV electron beam. The results from these and other physical property measurements are presented in this report

  16. Storage stability of biodegradable polyethylene glycol microspheres

    Science.gov (United States)

    Jain, Era; Sheth, Saahil; Polito, Kristen; Sell, Scott A.; Zustiak, Silviya P.

    2017-10-01

    Degradable hydrogel microspheres are popular choices for multiple biomedical applications, including drug, protein, or cell carriers for minimally invasive delivery. Clinical transitioning of such new, sensitive pharmaceutical preparations requires investigation of storage methods that retain key properties for extended time. In this study, we sought to determine the influence of seven common storage conditions on the physical and mechanical properties of degradable polyethylene glycol (PEG) hydrogel microspheres: 25 °C, 4 °C, -80 °C, lyophilization/-20 °C, dimethyl sulfoxide/-80 °C, dimethyl sulfoxide/lyophilization/-20 °C, vacuum/-20 °C. We have outlined the storage conditions in detail and explained their effect on swelling ratio, stiffness and degradation rate post-storage. Additionally, we have implemented protein-loaded hydrogels to evaluate the effect of storage conditions on diffusivity as well as protein stability post-storage. We found that hydrogels could be stored short-term (1-4 d) under moist conditions (i.e. storage without drying) without a substantial loss of properties. For extended storage (7-28 d), they could be stored either at  -80 °C (moist condition) or vacuum drying (dry condition).

  17. Demonstration of a switchable damping system to allow low-noise operation of high-Q low-mass suspension systems

    Science.gov (United States)

    Hennig, Jan-Simon; Barr, Bryan W.; Bell, Angus S.; Cunningham, William; Danilishin, Stefan L.; Dupej, Peter; Gräf, Christian; Hough, James; Huttner, Sabina H.; Jones, Russell; Leavey, Sean S.; Pascucci, Daniela; Sinclair, Martin; Sorazu, Borja; Spencer, Andrew; Steinlechner, Sebastian; Strain, Kenneth A.; Wright, Jennifer; Zhang, Teng; Hild, Stefan

    2017-12-01

    Low-mass suspension systems with high-Q pendulum stages are used to enable quantum radiation pressure noise limited experiments. Utilizing multiple pendulum stages with vertical blade springs and materials with high-quality factors provides attenuation of seismic and thermal noise; however, damping of these high-Q pendulum systems in multiple degrees of freedom is essential for practical implementation. Viscous damping such as eddy-current damping can be employed, but it introduces displacement noise from force noise due to thermal fluctuations in the damping system. In this paper we demonstrate a passive damping system with adjustable damping strength as a solution for this problem that can be used for low-mass suspension systems without adding additional displacement noise in science mode. We show a reduction of the damping factor by a factor of 8 on a test suspension and provide a general optimization for this system.

  18. Earth-ionosphere cavity

    International Nuclear Information System (INIS)

    Tran, A.; Polk, C.

    1976-01-01

    To analyze ELF wave propagation in the earth-ionosphere cavity, a flat earth approximation may be derived from the exact equations, which are applicable to the spherical cavity, by introducing a second-order or Debye approximation for the spherical Hankel functions. In the frequency range 3 to 30 Hz, however, the assumed conditions for the Debye approximation are not satisfied. For this reason an exact evaluation of the spherical Hankel functions is used to study the effects of the flat earth approximation on various propagation and resonance parameters. By comparing the resonance equation for a spherical cavity with its flat earth counterpart and by assuming that the surface impedance Z/sub i/ at the upper cavity boundary is known, the relation between the eigenvalue ν and S/sub v/, the sine of the complex angle of incidence at the lower ionosphere boundary, is established as ν(ν + 1) = (kaS/sub v/) 2 . It is also shown that the approximation ν(ν + 1) approximately equals (ν + 1/2) 2 which was used by some authors is not adequate below 30 Hz. Numerical results for both spherical and planar stratification show that (1) planar stratification is adequate for the computation of the lowest three ELF resonance frequencies to within 0.1 Hz; (2) planar stratification will lead to errors in cavity Q and wave attenuation which increase with frequency; (3) computation of resonance frequencies to within 0.1 Hz requires the extension of the lower boundary of the ionosphere to a height where the ratio of conduction current to displacement current, (sigma/ωepsilon 0 ), is less than 0.3; (4) atmospheric conductivity should be considered down to ground level in computing cavity Q and wave attenuation

  19. Development of nuclear fuel microsphere handling techniques and equipment

    International Nuclear Information System (INIS)

    Mack, J.E.; Suchomel, R.R.; Angelini, P.

    1979-01-01

    Considerable progress has been made in the development of microsphere handling techniques and equipment for nuclear applications. Work at Oak Ridge National Laboratory with microspherical fuel forms dates back to the early sixties with the development of the sol-gel process. Since that time a number of equipment items and systems specifically related to microsphere handling and characterization have been identified and developed for eventual application in a remote recycle facility. These include positive and negative pressure transfer systems, samplers, weighers, a blender-dispenser, and automated devices for particle size distribution and crushing strength analysis. The current status of these and other components and systems is discussed

  20. Materials for superconducting cavities

    International Nuclear Information System (INIS)

    Bonin, B.

    1996-01-01

    The ideal material for superconducting cavities should exhibit a high critical temperature, a high critical field, and, above all, a low surface resistance. Unfortunately, these requirements can be conflicting and a compromise has to be found. To date, most superconducting cavities for accelerators are made of niobium. The reasons for this choice are discussed. Thin films of other materials such as NbN, Nb 3 Sn, or even YBCO compounds can also be envisaged and are presently investigated in various laboratories. It is shown that their success will depend critically on the crystalline perfection of these films. (author)

  1. Experimental investigation of cavity flows

    Energy Technology Data Exchange (ETDEWEB)

    Loeland, Tore

    1999-12-31

    This thesis uses LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry) and Laser Sheet flow Visualisation to study flow inside three different cavity configurations. For sloping cavities, the vortex structure inside the cavities is found to depend upon the flow direction past the cavity. The shape of the downstream corner is a key factor in destroying the boundary layer flow entering the cavity. The experimental results agree well with numerical simulations of the same geometrical configurations. The results of the investigations are used to find the influence of the cavity flow on the accuracy of the ultrasonic flowmeter. A method to compensate for the cavity velocities is suggested. It is found that the relative deviation caused by the cavity velocities depend linearly on the pipe flow. It appears that the flow inside the cavities should not be neglected as done in the draft for the ISO technical report on ultrasonic flowmeters. 58 refs., 147 figs., 2 tabs.

  2. Experimental investigation of cavity flows

    Energy Technology Data Exchange (ETDEWEB)

    Loeland, Tore

    1998-12-31

    This thesis uses LDV (Laser Doppler Velocimetry), PIV (Particle Image Velocimetry) and Laser Sheet flow Visualisation to study flow inside three different cavity configurations. For sloping cavities, the vortex structure inside the cavities is found to depend upon the flow direction past the cavity. The shape of the downstream corner is a key factor in destroying the boundary layer flow entering the cavity. The experimental results agree well with numerical simulations of the same geometrical configurations. The results of the investigations are used to find the influence of the cavity flow on the accuracy of the ultrasonic flowmeter. A method to compensate for the cavity velocities is suggested. It is found that the relative deviation caused by the cavity velocities depend linearly on the pipe flow. It appears that the flow inside the cavities should not be neglected as done in the draft for the ISO technical report on ultrasonic flowmeters. 58 refs., 147 figs., 2 tabs.

  3. A Low-Noise CMOS THz Imager Based on Source Modulation and an In-Pixel High-Q Passive Switched-Capacitor N-Path Filter.

    Science.gov (United States)

    Boukhayma, Assim; Dupret, Antoine; Rostaing, Jean-Pierre; Enz, Christian

    2016-03-03

    This paper presents the first low noise complementary metal oxide semiconductor (CMOS) deletedCMOS terahertz (THz) imager based on source modulation and in-pixel high-Q filtering. The 31 × 31 focal plane array has been fully integrated in a 0 . 13 μ m standard CMOS process. The sensitivity has been improved significantly by modulating the active THz source that lights the scene and performing on-chip high-Q filtering. Each pixel encompass a broadband bow tie antenna coupled to an N-type metal-oxide-semiconductor (NMOS) detector that shifts the THz radiation, a low noise adjustable gain amplifier and a high-Q filter centered at the modulation frequency. The filter is based on a passive switched-capacitor (SC) N-path filter combined with a continuous-time broad-band Gm-C filter. A simplified analysis that helps in designing and tuning the passive SC N-path filter is provided. The characterization of the readout chain shows that a Q factor of 100 has been achieved for the filter with a good matching between the analytical calculation and the measurement results. An input-referred noise of 0 . 2 μ V RMS has been measured. Characterization of the chip with different THz wavelengths confirms the broadband feature of the antenna and shows that this THz imager reaches a total noise equivalent power of 0 . 6 nW at 270 GHz and 0 . 8 nW at 600 GHz.

  4. Investigation Into Accessible Surface Vinyl Concentrations of Nonstoichiometric PDMS Microspheres from Hydrosilylation Reactions and Their Further Crosslinking Reactions

    DEFF Research Database (Denmark)

    Ma, Baoguang; Hansen, Jens Henrik; Hvilsted, Søren

    2015-01-01

    The introduction of surface vinyl groups to PDMS microspheres broadens the latter's applicability range since the microspheres can be further functionalized or crosslinked into elastomers. Quantification of the surface vinyl concentration of PDMS microspheres is therefore essential. Here, a novel...

  5. Multipactors in klystron cavities

    International Nuclear Information System (INIS)

    Hayashi, Kazutaka; Iyeki, Hiroshi; Kikunaga, Toshiyuki.

    1993-01-01

    A multipactor phenomenon in a klystron causes gain shortage or instability problem. Some tests using a prototype klystron input cavity revealed the microwave discharges in vacuum with magnetic field. The test results and the methods to avoid multipactors are discussed in this paper. (author)

  6. What's a Cavity?

    Science.gov (United States)

    ... and deeper over time. Cavities are also called dental caries (say: KARE-eez), and if you have a ... made up mostly of the germs that cause tooth decay. The bacteria in your mouth make acids and when plaque clings to your teeth, the acids can eat away at the outermost ...

  7. Vertical cavity laser

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention provides a vertical cavity laser comprising a grating layer comprising an in-plane grating, the grating layer having a first side and having a second side opposite the first side and comprising a contiguous core grating region having a grating structure, wherein an index...

  8. Oral cavity and jaw

    International Nuclear Information System (INIS)

    Solntsev, A.M.; Koval', G.Yu.

    1984-01-01

    Radioanatome of oral cavity and jaw is described. Diseases of the teeth, jaw, large salivary glands, temporo-mandibular articulation are considered. Roentgenograms of oral cacity and jaw of healthy people are presented and analyzed as well as roentgenograms in the above-mentioned diseases

  9. Niobium superconducting cavity

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    This 5-cell superconducting cavity, made from bulk-Nb, stems from the period of general studies, not all directed towards direct use at LEP. This one is dimensioned for 1.5 GHz, the frequency used at CEBAF and also studied at Saclay (LEP RF was 352.2 MHz). See also 7908227, 8007354, 8209255, 8210054, 8312339.

  10. Superconducting elliptical cavities

    CERN Document Server

    Sekutowicz, J K

    2011-01-01

    We give a brief overview of the history, state of the art, and future for elliptical superconducting cavities. Principles of the cell shape optimization, criteria for multi-cell structures design, HOM damping schemes and other features are discussed along with examples of superconducting structures for various applications.

  11. Additive Manufactured Superconducting Cavities

    Science.gov (United States)

    Holland, Eric; Rosen, Yaniv; Woolleet, Nathan; Materise, Nicholas; Voisin, Thomas; Wang, Morris; Mireles, Jorge; Carosi, Gianpaolo; Dubois, Jonathan

    Superconducting radio frequency cavities provide an ultra-low dissipative environment, which has enabled fundamental investigations in quantum mechanics, materials properties, and the search for new particles in and beyond the standard model. However, resonator designs are constrained by limitations in conventional machining techniques. For example, current through a seam is a limiting factor in performance for many waveguide cavities. Development of highly reproducible methods for metallic parts through additive manufacturing, referred to colloquially as 3D printing\\x9D, opens the possibility for novel cavity designs which cannot be implemented through conventional methods. We present preliminary investigations of superconducting cavities made through a selective laser melting process, which compacts a granular powder via a high-power laser according to a digitally defined geometry. Initial work suggests that assuming a loss model and numerically optimizing a geometry to minimize dissipation results in modest improvements in device performance. Furthermore, a subset of titanium alloys, particularly, a titanium, aluminum, vanadium alloy (Ti - 6Al - 4V) exhibits properties indicative of a high kinetic inductance material. This work is supported by LDRD 16-SI-004.

  12. Cavity Nesting Birds

    Science.gov (United States)

    Virgil E. Scott; Keith E. Evans; David R. Patton; Charles P. Stone

    1977-01-01

    Many species of cavity-nesting birds have declined because of habitat reduction. In the eastern United States, where primeval forests are gone, purple martins depend almost entirely on man-made nesting structures (Allen and Nice 1952). The hole-nesting population of peregrine falcons disappeared with the felling of the giant trees upon which they depended (Hickey and...

  13. LEP superconducting cavity

    CERN Multimedia

    1995-01-01

    Engineers work in a clean room on one of the superconducting cavities for the upgrade to the LEP accelerator, known as LEP-2. The use of superconductors allow higher electric fields to be produced so that higher beam energies can be reached.

  14. Open microwave cavities

    Czech Academy of Sciences Publication Activity Database

    Šeba, Petr; Rotter, I.; Mueller, M.; Persson, C.; Pichugin, Konstantin N.

    2001-01-01

    Roč. 9, - (2001), s. 484-487 ISSN 1386-9477 Institutional research plan: CEZ:A02/98:Z1-010-914 Keywords : microwave cavity * resonances Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.009, year: 2001

  15. Filling a Conical Cavity

    Science.gov (United States)

    Nye, Kyle; Eslam-Panah, Azar

    2016-11-01

    Root canal treatment involves the removal of infected tissue inside the tooth's canal system and filling the space with a dense sealing agent to prevent further infection. A good root canal treatment happens when the canals are filled homogeneously and tightly down to the root apex. Such a tooth is able to provide valuable service for an entire lifetime. However, there are some examples of poorly performed root canals where the anterior and posterior routes are not filled completely. Small packets of air can be trapped in narrow access cavities when restoring with resin composites. Such teeth can cause trouble even after many years and lead the conditions like acute bone infection or abscesses. In this study, the filling of dead-end conical cavities with various liquids is reported. The first case studies included conical cavity models with different angles and lengths to visualize the filling process. In this investigation, the rate and completeness at which a variety of liquids fill the cavity were observed to find ideal conditions for the process. Then, a 3D printed model of the scaled representation of a molar with prepared post spaces was used to simulate the root canal treatment. The results of this study can be used to gain a better understanding of the restoration for endodontically treated teeth.

  16. Optical diffraction by ordered 2D arrays of silica microspheres

    International Nuclear Information System (INIS)

    Shcherbakov, A.A.; Shavdina, O.; Tishchenko, A.V.; Veillas, C.; Verrier, I.; Dellea, O.; Jourlin, Y.

    2017-01-01

    The article presents experimental and theoretical studies of angular dependent diffraction properties of 2D monolayer arrays of silica microspheres. High-quality large area defect-free monolayers of 1 μm diameter silica microspheres were deposited by the Langmuir-Blodgett technique under an accurate optical control. Measured angular dependencies of zeroth and one of the first order diffraction efficiencies produced by deposited samples were simulated by the rigorous Generalized Source Method taking into account particle size dispersion and lattice nonideality. - Highlights: • High quality silica microsphere monolayer was fabricated. • Accurate measurements of diffraction efficiency angular dependencies. • Rigorous diffraction simulation of both ideal hexagonal and realistic microsphere arrangements. • Qualitative rationalization of the obtained results and the observed differences between the experiment and the theory.

  17. BIOCOMPATIBLE FLUORESCENT MICROSPHERES: SAFE PARTICLES FOR MATERIAL PENETRATION STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Farquar, G; Leif, R

    2009-07-15

    Biocompatible polymers with hydrolyzable chemical bonds have been used to produce safe, non-toxic fluorescent microspheres for material penetration studies. The selection of polymeric materials depends on both biocompatibility and processability, with tailored fluorescent properties depending on specific applications. Microspheres are composed of USFDA-approved biodegradable polymers and non-toxic fluorophores and are therefore suitable for tests where human exposure is possible. Micropheres were produced which contain unique fluorophores to enable discrimination from background aerosol particles. Characteristics that affect dispersion and adhesion can be modified depending on use. Several different microsphere preparation methods are possible, including the use of a vibrating orifice aerosol generator (VOAG), a Sono-Tek atomizer, an emulsion technique, and inkjet printhead. Applications for the fluorescent microspheres include challenges for biodefense system testing, calibrants for biofluorescence sensors, and particles for air dispersion model validation studies.

  18. Preparation of UN microspheres by internal gelation process

    Energy Technology Data Exchange (ETDEWEB)

    Shirasu, Yoshiro; Yamagishi, Shigeru [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    UN microspheres were prepared from (UO{sub 3}+C) microspheres internally gelled in a hot silicone oil column. The gel microspheres were calcined at 480degC in nitrogen, after washing and drying. The calcined ones were carbothermically nitrided at 1400-1800degC in a nitrogen-based atmosphere in two ways: one in N{sub 2} followed by N{sub 2}-8%H{sub 2}, and the other in N{sub 2}-8%H{sub 2} only. In both cases, highly pure UN microspheres around 500 ppm of both oxygen and carbon impurities were obtained, although their densities were still low. (author)

  19. Silicon microspheres for near-IR communication applications

    International Nuclear Information System (INIS)

    Serpengüzel, Ali; Demir, Abdullah

    2008-01-01

    We have performed transverse electric and transverse magnetic polarized elastic light scattering calculations at 90° and 0° in the o-band at 1.3 µm for a 15 µm radius silicon microsphere with a refractive index of 3.5. The quality factors are on the order of 10 7 and the mode/channel spacing is 7 nm, which correlate well with the refractive index and the optical size of the microsphere. The 90° elastic light scattering can be used to monitor a dropped channel (drop port), whereas the 0° elastic scattering can be used to monitor the transmission channel (through port). The optical resonances of the silicon microspheres provide the necessary narrow linewidths that are needed for high-resolution optical communication applications. Potential telecommunication applications include filters, modulators, switches, wavelength converters, detectors, amplifiers and light sources. Silicon microspheres show promise as potential building blocks for silicon-based electrophotonic integration

  20. XPS analysis of aluminosilicate microspheres bioactivity tested in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Todea, M.; Vanea, E. [Faculty of Physics and Institute of Interdisciplinary Research on Bio-Nano-Sciences, Babes Bolyai University, Cluj-Napoca 400084 (Romania); Bran, S. [University of Medicine and Pharmacy “Iuliu Haţieganu”, Department of Cranio-Maxillofacial Surgery, 400029 Cluj-Napoca (Romania); Berce, P. [Technical University of Cluj-Napoca, Faculty of Machine Building and National Centre of Rapid Prototyping, 400641 Cluj-Napoca (Romania); Simon, S., E-mail: simons@phys.ubbcluj.ro [Faculty of Physics and Institute of Interdisciplinary Research on Bio-Nano-Sciences, Babes Bolyai University, Cluj-Napoca 400084 (Romania)

    2013-04-01

    The study aims to characterize surface properties of aluminosilicate microspheres incorporating yttrium, with potential biomedical applications. Micrometric particles of spherical shape were obtained by spray drying method. The behavior of aluminosilicate microspheres without yttrium and with yttrium was investigated under in vitro conditions, by seven days incubation in simulated body fluid (SBF). The surface elemental composition and the atomic environments on outermost layer of the microspheres, prior to and after incubation in SBF were evaluated by X-ray photoelectron spectroscopy (XPS) in order to investigate their bioactivity. The results were analyzed to underline the effect of yttrium addition on surface properties of the aluminosilicate microspheres and implicitly on the behavior of the samples in simulated body environments.

  1. Investigation of defects on PAMS microspheres fabricated with microencapsulation method

    International Nuclear Information System (INIS)

    Chen Sufen; Li Bo; Liu Yiyang; Zhang Zhanwen; Qi Xiaobo

    2012-01-01

    Poly-(α-methylstyrene) (PAMS) microspheres were fabricated with W1/O/W2 double emulsion microencapsulation method, and the effects of polyvinylalcohol (PVA) and CaCl 2 weight concentrations and the O/W2 phase ratio on the percentages of defected PAMS microspheres were studied. The weight concentrations of PVA and CaCl 2 and the O/W2 phase ratio in the fabrication process of PAMS microspheres were optimized. The results show that, for the three parameters being 1.0%, 1.5%, and 0.01, respectively, the percentage of the defect-free PAMS microspheres without vacuoles in the shell wall can be up to 60%. (authors)

  2. Preparation and In-vitro Evaluation of Metformin Microspheres Using ...

    African Journals Online (AJOL)

    . Methods: Metformin microspheres were prepared by non-aqueous solvent evaporation method using various polymers, including ethylcellulose (EC), hydroxypropyl methylcellulose (HPMC), carbopol 934P (CA) and chitosan (CH). The effect ...

  3. Investigation of concrete mixtures incorporating hollow plastic microspheres.

    Science.gov (United States)

    1981-01-01

    This study investigated the potential of hollow plastic microspheres, HPM, for providing non-air-entrained portland cement concrete resistance to damage from cycles of freezing and thawing. In the study, a mixture with an air-entraining agent (vinsol...

  4. Resonant microsphere gyroscope based on a double Faraday rotator system.

    Science.gov (United States)

    Xie, Chengfeng; Tang, Jun; Cui, Danfeng; Wu, Dajin; Zhang, Chengfei; Li, Chunming; Zhen, Yongqiu; Xue, Chenyang; Liu, Jun

    2016-10-15

    The resonant microsphere gyroscope is proposed based on a double Faraday rotator system for the resonant microsphere gyroscope (RMSG) that is characterized by low insertion losses and does not destroy the reciprocity of the gyroscope system. Use of the echo suppression structure and the orthogonal polarization method can effectively inhibit both the backscattering noise and the polarization error, and reduce them below the system sensitivity limit. The resonance asymmetry rate dropped from 34.2% to 2.9% after optimization of the backscattering noise and the polarization noise, which greatly improved the bias stability and the scale factor linearity of the proposed system. Additionally, based on the optimum parameters for the double Faraday rotator system, a bias stability of 0.04°/s has been established for an integration time of 10 s in 1000 s in a resonator microsphere gyroscope using a microsphere resonator with a diameter of 1 mm and a Q of 7.2×106.

  5. Controlled release of cavity states into propagating modes induced via a single qubit

    Science.gov (United States)

    Pfaff, Wolfgang; Constantin, Marius; Reagor, Matthew; Axline, Christopher; Blumoff, Jacob; Chou, Kevin; Leghtas, Zaki; Touzard, Steven; Heeres, Reinier; Reinhold, Philip; Ofek, Nissim; Sliwa, Katrina; Frunzio, Luigi; Mirrahimi, Mazyar; Lehnert, Konrad; Jiang, Liang; Devoret, Michel; Schoelkopf, Robert

    Photonic states stored in long-lived cavities are a promising platform for scalable quantum computing and for the realization of quantum networks. An important aspect in such a cavity-based architecture will be the controlled conversion of stored photonic states into propagating ones. This will allow, for instance, quantum state transfer between remote cavities. We demonstrate the controlled release of quantum states from a microwave resonator with millisecond lifetime in a 3D circuit QED system. Dispersive coupling of the cavity to a transmon qubit allows us to enable a four-wave mixing process that transfers the stored state into a second resonator from which it can leave the system through a transmission line. This permits us to evacuate the cavity on time scales that are orders of magnitude faster than the intrinsic lifetime. This Q-switching process can in principle be fully coherent, making our system highly promising for quantum state transfer between nodes in a quantum network of high-Q cavities.

  6. Implosion of the small cavity and large cavity cannonball targets

    International Nuclear Information System (INIS)

    Nishihara, Katsunobu; Yamanaka, Chiyoe.

    1984-01-01

    Recent results of cannonball target implosion research are briefly reviewed with theoretical predictions for GEKKO XII experiments. The cannonball targets are classified into two types according to the cavity size ; small cavity and large cavity. The compression mechanisms of the two types are discussed. (author)

  7. Facile preparation of hierarchically porous polymer microspheres for superhydrophobic coating

    Science.gov (United States)

    Gao, Jiefeng; Wong, Julia Shuk-Ping; Hu, Mingjun; Li, Wan; Li, Robert. K. Y.

    2013-12-01

    A facile method, i.e., nonsolvent assisted electrospraying, is proposed to fabricate hierarchically porous microspheres. The pore size on the microsphere surface ranges from a few tens to several hundred nanometers. Thermally and nonsolvent induced phase separation as well as breath figure is responsible for the formation of the hierarchical structures with different nano-sized pores. The nonsolvent could not only induce phase separation, but also stabilize the interface between the droplet and air, which can prevent the droplet from strong deformation, and is therefore beneficial to the formation of regular and uniform microspheres. On the other hand, solvent evaporation, polymer diffusion and Coulomb fission during electrospraying influence the morphology of finally obtained products. In this paper, the influence of polymer concentration, the weight ratio between nonsolvent and polymer and the flowing rate on the morphology of the porous microsphere is carefully studied. The hierarchically porous microsphere significantly increases the surface roughness and thus the hydrophobicity, and the contact angle can reach as high as 152.2 +/- 1.2°. This nonsolvent assisted electrospraying opens a new way to fabricate superhydrophobic coating materials.A facile method, i.e., nonsolvent assisted electrospraying, is proposed to fabricate hierarchically porous microspheres. The pore size on the microsphere surface ranges from a few tens to several hundred nanometers. Thermally and nonsolvent induced phase separation as well as breath figure is responsible for the formation of the hierarchical structures with different nano-sized pores. The nonsolvent could not only induce phase separation, but also stabilize the interface between the droplet and air, which can prevent the droplet from strong deformation, and is therefore beneficial to the formation of regular and uniform microspheres. On the other hand, solvent evaporation, polymer diffusion and Coulomb fission during

  8. [Optimization of riboflavin sodium phosphate loading to calcium alginate floating microspheres by response surface methodology].

    Science.gov (United States)

    Zhang, An-yang; Fan, Tian-yuan

    2009-12-18

    To investigate the preparation, optimization and in vitro properties of riboflavin sodium phosphate floating microspheres. The floating microspheres composed of riboflavin sodium phosphate and calcium alginate were prepared using ion gelatin-oven drying method. The properties of the microspheres were investigated, including the buoyancy, release, appearance and entrapment efficiency. The formulation was optimized by response surface methodology (RSM). The optimized microspheres were round. The entrapment efficiency was 57.49%. All the microspheres could float on the artificial gastric juice over 8 hours. The release of the drug from the microspheres complied with Fick's diffusion.

  9. A review on target drug delivery: magnetic microspheres

    OpenAIRE

    Amit Chandna; Deepa Batra; Satinder Kakar; Ramandeep Singh

    2013-01-01

    Novel drug delivery system aims to deliver the drug at a rate directed by the needs of the body during the period of treatment, and target the active entity to the site of action. A number of novel drug delivery systems have emerged encompassing various routes of administration, to achieve controlled and targeted drug delivery, magnetic micro carriers being one of them. Magnetic microsphere is newer approach in pharmaceutical field. Magnetic microspheres as an alternative to traditional ra...

  10. Development and Evaluation of Isoniazid Loaded Silk Fibroin Microsphere

    Directory of Open Access Journals (Sweden)

    Narinder Singh

    Full Text Available Aim: Current experimental investigation is dedicated to prepare microspheres with small size and good sphericity by Phase Separation method using Isoniazid (INH as model drug. Silk fibroin has unique intrinsic qualities like biodegradability, biocompatibility or release properties and their tunable drug loading capacity. The delivery loading proficiency of the drug molecules in silk spheres be contingent on their charge, and hydrophobicity or subsequent in altered drug release profiles. Methods: In the present work Isoniazid loaded silk fibroin microsphere was prepared by using phase separation method. Microsphere was evaluated for Ultraviolet-visible spectroscopy, Fourier Transform infrared spectroscopy, Entrapment efficiency, Scanning electron microscopy Studies. Results: Scanning electron microscopy studies revealed that Isoniazid Loaded Silk Fibroin Microspheres were spherical. Entrapment Efficiency of Isoniazid loaded Microspheres of different Formulation from F1 to F5 was in range of 53 to 68 %. F3 showed 68.47 % entrapment Efficiency and the optimized formulation drug release was 93.56 % at 24 hours. Conclusion: Experimental report disclosed a new aqueous based formulation method for silk spheres with controllable shape or size and sphere. Isoniazid loaded silk microspheres may act as ideal nano formulation with elaborated studies.

  11. Synthesis and characterization of Supeparamagnetics Microspheres (PMMA via suspension polymerization

    Directory of Open Access Journals (Sweden)

    Paulo Emilio Feuser

    2014-02-01

    Full Text Available Magnetics nanoparticles (NPMs has found many applications in biomedical and technological areas. The objective of this work is the preparation and characterization of PMMA microspheres containing NPMs coated with oleic acid (NPMs-AO. For the preparation of MNPs-AO was used the coprecipitation method in an aqueous medium. For the preparation of the superparamagnetic microspheres used in suspension polymerization technique. The microspheres showed a size distribution particles of approximately 150um and a spherical morphology. From the analysis of gel permeation chromatography (GPC determined the number average molecular weight (Mw of the magnetics microspheres and there was a variation in the Mw depending on the concentration of MNPs-AO in this reaction. To analyze the magnetic properties used the vibrating sample magnetometer (MAV. The microspheres showed superparamagnetic properties and a value of saturation magnetization (Ms of about 8 emu/g MNPs. Therefore you can conclude that it is possible to obtain superparamagnetics microspheres for a particular application, either, biomedical or technological.

  12. Innovative hydrogen storage in hollow glass-microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Keding, M.; Schmid, G.; Tajmar, M. [Austrian Research Centers, Vienna (Austria)

    2009-07-01

    Hydrogen storage technologies are becoming increasingly important for a number of future applications. The Austrian Research Centers (ARC) are developing a unique hydrogen storage system that combines the advantages of both hollow glass microsphere and chemical compound hydrogen storage, but eliminates their respective drawbacks. Water is utilized as a functional liquid to carry the hollow glass microspheres that are loaded with up to 700 bar of hydrogen gas. Sodium borohydride (NaBH{sub 4}) is then injected together with the glass microspheres into a reaction chamber where the water reacts catalytically with the NaBH{sub 4} producing hydrogen and heat. The heat is then utilized to release the hydrogen from the hollow glass microspheres providing a double hydrogen generation process without any external energy or heat during storage or gas release. The paper described this hydrogen storage system with particular reference to microspheres, the coating process, the experimental facility and NaBH{sub 4} test results. It was concluded that hydrogen storage and production on demand is possible with microspheres and sodium borohydride solution. 9 refs., 16 figs.

  13. Microspheres and Nanotechnology for Drug Delivery.

    Science.gov (United States)

    Jóhannesson, Gauti; Stefánsson, Einar; Loftsson, Thorsteinn

    2016-01-01

    Ocular drug delivery to the posterior segment of the eye can be accomplished by invasive drug injections into different tissues of the eye and noninvasive topical treatment. Invasive treatment involves the risks of surgical trauma and infection, and conventional topical treatments are ineffective in delivering drugs to the posterior segment of the eye. In recent years, nanotechnology has become an ever-increasing part of ocular drug delivery. In the following, we briefly review microspheres and nanotechnology for drug delivery to the eye, including different forms of nanotechnology such as nanoparticles, microparticles, liposomes, microemulsions and micromachines. The permeation barriers and anatomical considerations linked to ocular drug delivery are discussed and a theoretical overview on drug delivery through biological membranes is given. Finally, in vitro, in vivo and human studies of x03B3;-cyclodextrin nanoparticle eyedrop suspensions are discussed as an example of nanotechnology used for drug delivery to the eye. © 2016 S. Karger AG, Basel.

  14. Encoding quantum information in a stabilized manifold of a superconducting cavity

    Science.gov (United States)

    Touzard, S.; Leghtas, Z.; Mundhada, S. O.; Axline, C.; Reagor, M.; Chou, K.; Blumoff, J.; Sliwa, K. M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Mirrahimi, M.; Devoret, M. H.

    In a superconducting Josephson circuit architecture, we activate a multi-photon process between two modes by applying microwave drives at specific frequencies. This creates a pairwise exchange of photons between a high-Q cavity and the environment. The resulting open dynamical system develops a two-dimensional quasi-energy ground state manifold. Can we encode, protect and manipulate quantum information in this manifold? We experimentally investigate the convergence and escape rates in and out of this confined subspace. Finally, using quantum Zeno dynamics, we aim to perform gates which maintain the state in the protected manifold at all times. Work supported by: ARO, ONR, AFOSR and YINQE.

  15. Chitosan microspheres in novel drug delivery systems.

    Science.gov (United States)

    Mitra, Analava; Dey, Baishakhi

    2011-07-01

    The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems.

  16. Hollow waveguide cavity ringdown spectroscopy

    Science.gov (United States)

    Dreyer, Chris (Inventor); Mungas, Greg S. (Inventor)

    2012-01-01

    Laser light is confined in a hollow waveguide between two highly reflective mirrors. This waveguide cavity is used to conduct Cavity Ringdown Absorption Spectroscopy of loss mechanisms in the cavity including absorption or scattering by gases, liquid, solids, and/or optical elements.

  17. Optimization of photonic crystal cavities

    DEFF Research Database (Denmark)

    Wang, Fengwen; Sigmund, Ole

    2017-01-01

    We present optimization of photonic crystal cavities. The optimization problem is formulated to maximize the Purcell factor of a photonic crystal cavity. Both topology optimization and air-hole-based shape optimization are utilized for the design process. Numerical results demonstrate...... that the Purcell factor of the photonic crystal cavity can be significantly improved through optimization....

  18. Nuclear reactor cavity streaming shield

    International Nuclear Information System (INIS)

    Klotz, R.J.; Stephen, D.W.

    1978-01-01

    The upper portion of a nuclear reactor vessel supported in a concrete reactor cavity has a structure mounted below the top of the vessel between the outer vessel wall and the reactor cavity wall which contains hydrogenous material which will attenuate radiation streaming upward between vessel and the reactor cavity wall while preventing pressure buildup during a loss of coolant accident

  19. Colloquium: cavity optomechanics

    CERN Multimedia

    2011-01-01

    Monday 14 November 2011, 17:00 Ecole de Physique, Auditoire Stueckelberg Université de Genève Cavity optomechanics: controlling micro mechanical oscillators with laser light Prof. Tobias Kippenberg EPFL, Lausanne Laser light can be used to cool and to control trapped ions, atoms and molecules at the quantum level. This has lead to spectacular advances such as the most precise atomic clocks. An outstanding frontier is the control with lasers of nano- and micro-mechancial systems. Recent advances in cavity optomechanics have allowed such elementary control for the first time, enabling mechanical systems to be ground state cooled leading to readout with quantum limited sensitivity and permitting to explore new device concepts resulting from radiation pressure.  

  20. Leaching materials from cavities

    International Nuclear Information System (INIS)

    Hodgson, T.D.; Jordan, T.W.J.

    1980-01-01

    A material is leached from a cavity by contacting the material with a liquid and subjecting the liquid to a number of pressure cycles, each pressure cycle involving a decrease in pressure to cause boiling of the liquid, followed by a rise in pressure to inhibit the boiling. The method may include the step of heating the liquid to a temperature near to its boiling point. The material may be nuclear fuel pellets or calcium carbonate pellets. (author)

  1. Superconducting cavities for HERA

    International Nuclear Information System (INIS)

    Dwersteg, B.; Ebeling, W.; Moeller, W.D.; Renken, D.; Proch, D.; Sekutowicz, J.; Susta, J.; Tong, D.

    1988-01-01

    Superconducting 500 MHz cavities are developed to demonstrate the feasibility of upgrading the e-beam energy of the HERA storage ring. A prototype module with 2 x 4 cell resonators and appropriate fundamental and higher mode couplers has been designed at DESY and is being built by industrial firms. The design and results of RF and cryogenic measurements are reported in detail. 17 references, 10 figures, 2 tables

  2. A Low-Noise CMOS THz Imager Based on Source Modulation and an In-Pixel High-Q Passive Switched-Capacitor N-Path Filter

    Science.gov (United States)

    Boukhayma, Assim; Dupret, Antoine; Rostaing, Jean-Pierre; Enz, Christian

    2016-01-01

    This paper presents the first low noise complementary metal oxide semiconductor (CMOS) terahertz (THz) imager based on source modulation and in-pixel high-Q filtering. The 31×31 focal plane array has been fully integrated in a 0.13μm standard CMOS process. The sensitivity has been improved significantly by modulating the active THz source that lights the scene and performing on-chip high-Q filtering. Each pixel encompass a broadband bow tie antenna coupled to an N-type metal-oxide-semiconductor (NMOS) detector that shifts the THz radiation, a low noise adjustable gain amplifier and a high-Q filter centered at the modulation frequency. The filter is based on a passive switched-capacitor (SC) N-path filter combined with a continuous-time broad-band Gm-C filter. A simplified analysis that helps in designing and tuning the passive SC N-path filter is provided. The characterization of the readout chain shows that a Q factor of 100 has been achieved for the filter with a good matching between the analytical calculation and the measurement results. An input-referred noise of 0.2μV RMS has been measured. Characterization of the chip with different THz wavelengths confirms the broadband feature of the antenna and shows that this THz imager reaches a total noise equivalent power of 0.6 nW at 270 GHz and 0.8 nW at 600 GHz. PMID:26950131

  3. Crab cavities for linear colliders

    CERN Document Server

    Burt, G; Carter, R; Dexter, A; Tahir, I; Beard, C; Dykes, M; Goudket, P; Kalinin, A; Ma, L; McIntosh, P; Shulte, D; Jones, Roger M; Bellantoni, L; Chase, B; Church, M; Khabouline, T; Latina, A; Adolphsen, C; Li, Z; Seryi, Andrei; Xiao, L

    2008-01-01

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  4. The synthesis and photocatalytic activity of ZnSe microspheres

    International Nuclear Information System (INIS)

    Cao Huaqiang; Xiao Yujiang; Zhang Sichun

    2011-01-01

    This paper reports the synthesis of semiconductor ZnSe microspheres composed of nanoparticles via a solvothermal route between the organic molecule selenophene (C 4 H 4 Se) and ZnCl 2 without adding any surfactant. The ZnSe microspheres were characterized by x-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), specific surface area measurement, and photoluminescence (PL) spectra. A strong and broad blue PL emission at 443 nm in wavelength (∼2.79 eV in photon energy) is attributed to the near-band-edge (NBE) emission of ZnSe, while the 530 nm peak is a defect-related (DL) emission. The photocatalytic activity of the as-prepared ZnSe microspheres was evaluated by photodegradation of methyl orange (MO) dye under ultraviolet (UV) light and visible light irradiation. The degradations of MO reach 94% or 95.1%, close to 100%, in the presence of the as-synthesized ZnSe microspheres or commercial ZnSe powder after 7 or 10 h under UV irradiation, respectively. Meanwhile the degradations of MO reach 94.3% or 60.6% in the presence of the as-synthesized ZnSe microspheres or commercial ZnSe powder after 12 h, respectively. The degradation rate of ZnSe microspheres is twice that of ZnSe commercial powder under UV light irradiation, and three times under visible light irradiation. The degradation process of MO dye on ZnSe microspheres under UV or visible light is also discussed.

  5. Microsphere-based super-resolution scanning optical microscope.

    Science.gov (United States)

    Huszka, Gergely; Yang, Hui; Gijs, Martin A M

    2017-06-26

    High-refractive index dielectric microspheres positioned within the field of view of a microscope objective in a dielectric medium can focus the light into a so-called photonic nanojet. A sample placed in such nanojet can be imaged by the objective with super-resolution, i.e. with a resolution beyond the classical diffraction limit. However, when imaging nanostructures on a substrate, the propagation distance of a light wave in the dielectric medium in between the substrate and the microsphere must be small enough to reveal the sample's nanometric features. Therefore, only the central part of an image obtained through a microsphere shows super-resolution details, which are typically ∼100 nm using white light (peak at λ = 600 nm). We have performed finite element simulations of the role of this critical distance in the super-resolution effect. Super-resolution imaging of a sample placed beneath the microsphere is only possible within a very restricted central area of ∼10 μm 2 , where the separation distance between the substrate and the microsphere surface is very small (∼1 μm). To generate super-resolution images over larger areas of the sample, we have fixed a microsphere on a frame attached to the microscope objective, which is automatically scanned over the sample in a step-by-step fashion. This generates a set of image tiles, which are subsequently stitched into a single super-resolution image (with resolution of λ/4-λ/5) of a sample area of up to ∼10 4 μm 2 . Scanning a standard optical microscope objective with microsphere therefore enables super-resolution microscopy over the complete field-of-view of the objective.

  6. Preparation of open porous polycaprolactone microspheres and their applications as effective cell carriers in hydrogel system

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Qingchun [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China); Tan, Ke; Ye, Zhaoyang [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 China (China); Zhang, Yan, E-mail: zhang_yan@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China); Tan, Wensong [State Key Laboratory of Bioreactor Engineering, School of Bioengineering, East China University of Science and Technology, Shanghai, 200237 China (China); Lang, Meidong, E-mail: mdlang@ecust.edu.cn [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering (China)

    2012-12-01

    Common hydrogel, composed of synthetic polymers or natural polysaccharides could not support the adhesion of anchorage-dependent cells due to the lack of cell affinitive interface and high cell constraint. The use of porous polyester microspheres as cell-carriers and introduction of cell-loaded microspheres into the hydrogel system might overcome the problem. However, the preparation of the open porous microsphere especially using polycaprolactone (PCL) has been rarely reported. Here, the open porous PCL microspheres were fabricated via the combined emulsion/solvent evaporation and particle leaching method. The microspheres exhibited porous surface and inter-connective pore structure. Additionally, the pore structure could be easily controlled by adjusting the processing parameters. The surface pore size could be altered from 20 {mu}m to 80 {mu}m and the internal porosities were varied from 30% to 70%. The obtained microspheres were evaluated to delivery mesenchymal stem cells (MSCs) and showed the improved cell adhesion and growth when compared with the non-porous microspheres. Then, the MSCs loaded microspheres were introduced into agarose hydrogel. MSCs remained alive and sustained proliferation in microsphere/agarose composite in 5-day incubation while a decrement of MSCs viabilities was found in agarose hydrogel without microspheres. The results indicated that the microsphere/hydrogel composite had a great potential in cell therapy and injectable system for tissue regeneration. Highlights: Black-Right-Pointing-Pointer The open porous polycaprolactone microspheres were fabricated using paraffin as a porogen. Black-Right-Pointing-Pointer The microspheres exhibited porous surface and inter-connective pore structure. Black-Right-Pointing-Pointer The surface and internal pore size and porosity of microsphere could be controlled. Black-Right-Pointing-Pointer The porous microspheres exhibited an improved cell adhesion and proliferation. Black

  7. Ulex europaeus 1 lectin targets microspheres to mouse Peyer's patch M-cells in vivo.

    Science.gov (United States)

    Foster, N; Clark, M A; Jepson, M A; Hirst, B H

    1998-03-01

    The interaction of latex microspheres with mouse Peyer's patch membranous M-cells was studied in a mouse gut loop model after the microspheres were coated with a variety of agents. Carboxylated microspheres (diameter 0.5 micron) were covalently coated with lectins Ulex europaeus 1, Concanavalin A, Euonymus europaeus and Bandeiraea simplicifolia 1 isolectin-B4, human immunoglobulin A or bovine serum albumin. Of the treatments examined, only Ulex europaeus (UEA1) resulted in significant selective binding of microspheres to M-cells. UEA1-coated microspheres bound to M-cells at a level 100-fold greater than BSA-coated microspheres, but binding to enterocytes was unaffected. Incubation of UEA1-coated microspheres with alpha-L-fucose reduced M-cell binding to a level comparable with BSA-coated microspheres. This indicated that targeting by UEA1 was via a carbohydrate receptor on the M-cell surface. Adherence of UEA1-coated microspheres to M-cells occurred within 10 min of inoculation into mouse gut loops and UEA1-coated microspheres were transported to 10 microns below the apical surface of M-cells within 60 min of inoculation. UEA1-coated microspheres also targeted mouse Peyer's patch M-cells after intragastric administration. These results demonstrated that altering the surface chemistry of carboxylated polystyrene microspheres increased M-cell targeting, suggesting a strategy to enhance delivery of vaccine antigens to the mucosal immune system.

  8. A reproducible accelerated in vitro release testing method for PLGA microspheres.

    Science.gov (United States)

    Shen, Jie; Lee, Kyulim; Choi, Stephanie; Qu, Wen; Wang, Yan; Burgess, Diane J

    2016-02-10

    The objective of the present study was to develop a discriminatory and reproducible accelerated in vitro release method for long-acting PLGA microspheres with inner structure/porosity differences. Risperidone was chosen as a model drug. Qualitatively and quantitatively equivalent PLGA microspheres with different inner structure/porosity were obtained using different manufacturing processes. Physicochemical properties as well as degradation profiles of the prepared microspheres were investigated. Furthermore, in vitro release testing of the prepared risperidone microspheres was performed using the most common in vitro release methods (i.e., sample-and-separate and flow through) for this type of product. The obtained compositionally equivalent risperidone microspheres had similar drug loading but different inner structure/porosity. When microsphere particle size appeared similar, porous risperidone microspheres showed faster microsphere degradation and drug release compared with less porous microspheres. Both in vitro release methods investigated were able to differentiate risperidone microsphere formulations with differences in porosity under real-time (37 °C) and accelerated (45 °C) testing conditions. Notably, only the accelerated USP apparatus 4 method showed good reproducibility for highly porous risperidone microspheres. These results indicated that the accelerated USP apparatus 4 method is an appropriate fast quality control tool for long-acting PLGA microspheres (even with porous structures). Copyright © 2015 Elsevier B.V. All rights reserved.

  9. ISR RF cavities

    CERN Multimedia

    1983-01-01

    In each ISR ring the radiofrequency cavities were installed in one 9 m long straight section. The RF system of the ISR had the main purpose to stack buckets of particles (most of the time protons)coming from the CPS and also to accelerate the stacked beam. The installed RF power per ring was 18 kW giving a peak accelerating voltage of 20 kV. The system had a very fine regulation feature allowing to lower the voltage down to 75 V in a smooth and well controlled fashion.

  10. A review on target drug delivery: magnetic microspheres

    Directory of Open Access Journals (Sweden)

    Amit Chandna

    2013-01-01

    Magnetic microsphere is newer approach in pharmaceutical field. Magnetic microspheres as an alternative to traditional radiation methods which use highly penetrating radiation that is absorbed throughout the body. Its use is limited by toxicity and side effects. The aim of the specific targeting is to enhance the efficiency of drug delivery & at the same time to reduce the toxicity & side effects. This kind of delivery system is very much important which localises the drug to the disease site. In this larger amount of freely circulating drug can be replaced by smaller amount of magnetically targeted drug. Magnetic carriers receive magnetic responses to a magnetic field from incorporated materials that are used for magnetic microspheres are chitosan, dextran etc. magnetic microspheres can be prepared from a variety of carrier material. One of the most utilized is serum albumin from human or other appropriate species. Drug release from albumin microspheres can be sustained or controlled by various stabilization procedures generally involving heat or chemical cross-linking of the protein carrier matrix.

  11. Magnetic propulsion of microspheres at liquid-glass interfaces

    Science.gov (United States)

    Helgesen, Geir

    2018-02-01

    Bio-coated, magnetic microspheres have many applications in biotechnology and medical technology as a tool to separate and extract cells or molecules in a water solution by applying external strong magnetic field gradients. However, magnetic microspheres with or without attached cargo can also be separated in the liquid solution if they are exposed to alternating or rotating, relatively weak magnetic fields. Microspheres that have a higher density than the liquid will approach the bottom surface of the sample cell, and then a combination of viscous and surface frictional forces can propel the magnetic microspheres along the surface in a direction perpendicular to the axis of field rotation. Experiments demonstrating this type of magnetic propulsion are shown, and the forces active in the process are discussed. The motion of particles inside sample cells that were tilted relative to the horizontal direction was studied, and the variation of propulsion velocity as a function of tilt angle was used to find the values of different viscous and mechanical parameters of motion. Propulsion speeds of up to 5 μm/s were observed and were found to be caused by a partly rolling and partly slipping motion of rotating microspheres with a slipping coefficient near 0.6.

  12. Pharmacodynamics of diclofenac from novel Eudragit entrapped microspheres.

    Science.gov (United States)

    Momoh, M A; Kenechukwu, F C; Adedokun, M O; Odo, C E; Attama, A A

    2014-05-01

    Effective clinical utilization of non-steroidal anti-inflammatory drugs such as diclofenac sodium (DS) is significantly limited by their ulcerogenic potential and poor bioavailability after oral administration, thus necessitating the need for a better carrier to minimize these obvious limitations. The objective of this study was to evaluate Eudragit® RS100/RL100 microspheres formulated by the solvent-evaporation technique for improved delivery of diclofenac. Three batches of (DF1, DF2 and DF3) microspheres were prepared using different ratios of Eudragit RS-100 and RL-100 polymers based on the solvent-evaporation method. The microspheres were characterized based on morphological properties, particle size analysis and encapsulation efficiency (EE%). In vitro release of DS was investigated in both 0.1 N HCl (pH 1.2) and phosphate-buffered saline (pH 7.4), while anti-inflammatory studies were evaluated in the rat model. Maximum EE% of 86.61 ± 0.11, 88.14 ± 0.16 and 85.50 ± 0.21 was obtained for DF1, DF2 and DF3, respectively. Discrete, smooth and brownish microspheres of size range 437 ± 0.01-479 ± 0.21 µm were obtained. Release of DS from the formulation depends on the polymer ratio. All the batches exhibited good anti-inflammatory activities. Microsphere formulations based on Eudragit® polymers would likely offer a reliable and alternative means of delivering DS orally.

  13. Iron Nanoparticles-Encapsulating Silica Microspheres for Arterial Embolization Hyperthermia

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z; Kawashita, M, E-mail: zhixia@ecei.tohoku.ac.jp [Graduate School of Biomedical Engineering, Tohoku University (Japan)

    2011-10-29

    We attempted to prepare {alpha}-Fe-encapsulating silica ({alpha}FeSi) microspheres by a sol-gel process using tetramethoxysilane (TMOS) in water-in-oil emulsion. The effect of preparation conditions on the structure, magnetic and heating properties of resultant products were investigated. Oil phase consisted of kerosene with 32 wt% of surfactants (sorbitan monooleate / sorbitan monostearate in 3:1 weight ratio). Water phase consisted of TMOS, ethanol (CH{sub 2}CH{sub 3}OH), water and iron nitrate (Fe(NO{sub 3}){sub 3{center_dot}}9H{sub 2}O) with TMOS / CH{sub 2}CH{sub 3}OH/H{sub 2}O/Fe{sup 3+} in 1:7.4:16.2:0.4{approx}1.2 molar ratio. Fe{sup 3+}-containing silica gel (FeSiG) microspheres 5 to 30 {mu}m in size were successfully obtained by adding the water phase into the oil phase at 60 deg. C under stirring of 1500 rpm for 100 min. {alpha}FeSi microspheres was obtained by heating the FeSiG microspheres at 850deg. C in argon atmosphere. The obtained {alpha}FeSi microspheres have a saturation magnetization (Ms) up to 21 emu g{sup -1} and a coercive force (Hc) of 133 Oe. The in vitro heating generation was evaluated under an alternating current (AC) magnetic field of 300 Oe and 100 kHz.

  14. Solvent/Non-Solvent Sintering To Make Microsphere Scaffolds

    Science.gov (United States)

    Laurencin, Cato T.; Brown, Justin L.; Nair, Lakshmi

    2011-01-01

    A solvent/non-solvent sintering technique has been devised for joining polymeric microspheres to make porous matrices for use as drug-delivery devices or scaffolds that could be seeded with cells for growing tissues. Unlike traditional sintering at elevated temperature and pressure, this technique is practiced at room temperature and pressure and, therefore, does not cause thermal degradation of any drug, protein, or other biochemical with which the microspheres might be loaded to impart properties desired in a specific application. Also, properties of scaffolds made by this technique are more reproducible than are properties of comparable scaffolds made by traditional sintering. The technique involves the use of two miscible organic liquids: one that is and one that is not a solvent for the affected polymer. The polymeric microspheres are placed in a mold having the size and shape of the desired scaffold, then the solvent/non-solvent mixture is poured into the mold to fill the void volume between the microspheres, then the liquid mixture is allowed to evaporate. Some of the properties of the resulting scaffold can be tailored through choice of the proportions of the liquids and the diameter of the microspheres.

  15. Research progress of fabricating polyvinyl alcohol coating on plastic microsphere

    International Nuclear Information System (INIS)

    Su Lin; Chen Sufen; Liu Meifang; Zhang Zhanwen; Yao Hong; Li Bo; Liu Yiyang

    2012-01-01

    In the procedures of designing polystyrene-polyvinyl alcohol-CH (carbon and hydrogen elements) (PS-PVA-CH) triple-layer microspheres, there are many methods such as drop-tower technique, emulsion micro-encapsulation, dip (spin) coating, interfacial polycondensation, and spraying technique to prepare the PVA coating. Drop-tower technique, emulsion micro-encapsulation and dip (spin) coating are most-commonly used. The advantages, disadvantages and the research progress of the three methods are summarized in this paper. Emulsion micro-encapsulation is suitable for preparing double-layer microspheres of sizes smaller then 500 μm, with high survival ratio and good quality. However, the preparation process is easily influenced by artificial factors. Small-sized double-layer microspheres can also be prepared by the drop-tower technique, and the preparation period is short. But there are still some problems such as the difficulty in designing the droplet generator, uneven PVA coating and the difficulty in preparing large-sized microspheres. Dip (spin) coating technique can be used to prepare PS-PVA microspheres with sizes larger than 1000 μm, but the spread of PVA coating is affected by many factors in this method, and the prepared PVA coating is too thin and not uniform. (authors)

  16. Optimization of the microwave coupler and microwave measurements of the microtron cavity for 20 MeV pre-injector microtron for INDUS-I SRS

    International Nuclear Information System (INIS)

    Wanmode, Y.D.; Shrivastava, Purushottam; Hannurkar, P.R.

    2003-01-01

    A 20 MeV microtron was developed indigenously by CAT for pre-injection of 20 MeV electrons to the 450 MeV/700 MeV Booster Synchrotron for INDUS-I and INDUS-II Synchrotron Radiation Sources. The injector microtron uses a high Q microwave cavity for acceleration of electrons. The microwave power is fed to the microtron cavity through an iris type coupler whose dimensions are optimized for the coupling factor and resonant frequency for the accelerator. The present paper gives the procedure details for coupling factor optimization, tuning of the resonant frequency and results achieved. (author)

  17. IVIVC from Long Acting Olanzapine Microspheres

    Directory of Open Access Journals (Sweden)

    Susan D'Souza

    2014-01-01

    Full Text Available In this study, four PLGA microsphere formulations of Olanzapine were characterized on the basis of their in vitro behavior at 37°C, using a dialysis based method, with the goal of obtaining an IVIVC. In vivo profiles were determined by deconvolution (Nelson-Wagner method and using fractional AUC. The in vitro and in vivo release profiles exhibited the same rank order of drug release. Further, in vivo profiles obtained with both approaches were nearly superimposable, suggesting that fractional AUC could be used as an alternative to the Nelson-Wagner method. A comparison of drug release profiles for the four formulations revealed that the in vitro profile lagged slightly behind in vivo release, but the results were not statistically significant (P0.96 between in vitro release and in vivo measurements confirmed the excellent relationship between in vitro drug release and the amount of drug absorbed in vivo. The results of this study suggest that proper selection of an in vitro method will greatly aid in establishing a Level A IVIVC for long acting injectables.

  18. Oral cavity eumycetoma

    Directory of Open Access Journals (Sweden)

    Gisele Alborghetti Nai

    2011-06-01

    Full Text Available Mycetoma is a pathological process in which eumycotic (fungal or actinomycotic causative agents from exogenous source produce grains. It is a localized chronic and deforming infectious disease of subcutaneous tissue, skin and bones. We report the first case of eumycetoma of the oral cavity in world literature. CASE REPORT: A 43-year-old male patient, complaining of swelling and fistula in the hard palate. On examination, swelling of the anterior and middle hard palate, with fistula draining a dark liquid was observed. The panoramic radiograph showed extensive radiolucent area involving the region of teeth 21-26 and the computerized tomography showed communication with the nasal cavity, suggesting the diagnosis of periapical cyst. Surgery was performed to remove the lesion. Histopathological examination revealed purulent material with characteristic grain. Gram staining for bacteria was negative and Grocott-Gomori staining for the detection of fungi was positive, concluding the diagnosis of eumycetoma. The patient was treated with ketoconazole for nine months, and was considered cured at the end of treatment. CONCLUSION: Histopathological examination, using histochemical staining, and direct microscopic grains examination can provide the distinction between eumycetoma and actinomycetoma accurately.

  19. Cryostat for TRISTAN superconducting cavity

    International Nuclear Information System (INIS)

    Mitsunobu, S.; Furuya, T.; Hara, K.

    1990-01-01

    Superconducting cavities generate rather high heat load of hundreds watts in one cryostat and have high sensitivity for pressure. We adopted usual pool-boiling type cooling for its stable pressure operation. Two 5-cell Nb cavities were installed in one flange type cryostat. Tuning mechanics actuated by a pulse-motor and a Piezo-electric element are set at outside of vacuum end flange. The design and performance of the cryostat for TRISTAN superconducting cavities are described. (author)

  20. Superconducting Radio-Frequency Cavities

    Science.gov (United States)

    Padamsee, Hasan S.

    2014-10-01

    Superconducting cavities have been operating routinely in a variety of accelerators with a range of demanding applications. With the success of completed projects, niobium cavities have become an enabling technology, offering upgrade paths for existing facilities and pushing frontier accelerators for nuclear physics, high-energy physics, materials science, and the life sciences. With continued progress in basic understanding of radio-frequency superconductivity, the performance of cavities has steadily improved to approach theoretical capabilities.

  1. Miniature chemical sensor combining molecular recognition with evanescent wave cavity ring-down spectroscopy

    International Nuclear Information System (INIS)

    Pipino, Andrew C. R.

    2004-01-01

    A new chemical detection technology has been realized that addresses DOE environmental management needs. The new technology is based on a variant of the sensitive optical absorption technique, cavity ring-down spectroscopy (CRDS). Termed evanescent-wave cavity ring-down spectroscopy (EW-CRDS), the technology employs a miniature solid-state optical resonator having an extremely high Q-factor as the sensing element, where the high-Q is achieved by using ultra-low-attenuation optical materials, ultra-smooth surfaces, and ultra-high reflectivity coatings, as well as low-diffraction-loss designs. At least one total-internal reflection (TIR) mirror is integral to the resonator permitting the concomitant evanescent wave to probe the ambient environment. Several prototypes have been designed, fabricated, characterized, and applied to chemical detection. Moreover, extensions of the sensing concept have been explored to enhance selectivity, sensitivity, and range of application. Operating primarily in the visible and near IR regions, the technology inherently enables remote detection by optical fiber. Producing 11 archival publications, 5 patents, 19 invited talks, 4 conference proceedings, a CRADA, and a patent-license agreement, the project has realized a new chemical detection technology providing >100 times more sensitivity than comparable technologies, while also providing practical advantages

  2. Investigations of a voltage-biased microwave cavity for quantum measurements of nanomechanical resonators

    Science.gov (United States)

    Rouxinol, Francisco; Hao, Hugo; Lahaye, Matt

    2015-03-01

    Quantum electromechanical systems incorporating superconducting qubits have received extensive interest in recent years due to their promising prospects for studying fundamental topics of quantum mechanics such as quantum measurement, entanglement and decoherence in new macroscopic limits, also for their potential as elements in technological applications in quantum information network and weak force detector, to name a few. In this presentation we will discuss ours efforts toward to devise an electromechanical circuit to strongly couple a nanomechanical resonator to a superconductor qubit, where a high voltage dc-bias is required, to study quantum behavior of a mechanical resonator. Preliminary results of our latest generation of devices integrating a superconductor qubit into a high-Q voltage biased microwave cavities are presented. Developments in the circuit design to couple a mechanical resonator to a qubit in the high-Q voltage bias CPW cavity is discussed as well prospects of achieving single-phonon measurement resolution. National Science Foundation under Grant No. DMR-1056423 and Grant No. DMR-1312421.

  3. Automated characterization of glass microspheres used for laser fusion experiments

    International Nuclear Information System (INIS)

    Tajima, Tsuyoshi; Norimatsu, Takayoshi; Izawa, Yasukazu; Yamanaka, Chiyoe.

    1985-01-01

    In laser fusion experiments glass microspheres of 100 to 1000 μm in diameter and 1 to 20 μm in wall thickness are most commonly used as fuel containers. The glass microspheres should be characterized precisely to meet stringent experimental requirements. Much time is consumed to characterize and select good quality spheres among thousands of spheres. We have developed an automated system to characterize and select glass microspheres. The system consists of charger, quadrupole rail, image processing and X-Y stage control with micro-computer. Total processing time primarily depends on the time required for image analysis, which should be compromised with the accuracy of characterization. The time for simple characterization requires about 10 sec. at present. (author)

  4. Preparation of alumina microspheres. Its application as in inorganic exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Santos, W.R. dos; Abrao, A [Instituto de Pesquisas Energeticas e Nucleares, Sao Paulo (Brazil). Centro de Engenharia Quimica

    1980-01-01

    Inorganic exchangers are widely used for adsorption and column partition chromatography. The main difficulty of using commercial alumina (in powder) for column chromatography is related to its packing, and the operations through the column become diffcult and time-consuming; also it turns to be virtually impossible to use large dimension columns. In order to eliminate these problems, a process for the preparation of alumina microspheres was developed as an adaptation of a similar process used to prepare nuclear fuel microspheres (UO/sub 2/, ThO/sub 2/). The flowsheet of this process is presented together with the analytical results of sphericity after calcination, granulometry, density and characterization by X-ray diffractometry. Solubility tests showed that the so-prepared microspheres are well resistant to strong acids and bases; retention tests showed their efficiency, mainly to copper.

  5. Electrodepositing of Au on hollow PS micro-spheres

    International Nuclear Information System (INIS)

    Sun Jingyuan; Zhang Yunwang; Du Kai; Wan Xiaobo; Xiao Jiang; Zhang Wei; Zhang Lin; Chen Jing

    2010-01-01

    Using the self-regulating new micro-sphere electrodepositing device, the techniques of electrodepositing gold on hollow PS micro-spheres were established. The experiment was carried out under the following conditions: voltage was about 0.7 ∼ 0.8 V, current density was 2.0 mA · cm -2 , the temperature was 45 degree C, cathode rotating rate was 250 r · min -1 , flow rate of the solution was 7 mL · min -1 · cm -2 . Hollow gold-plated micro-spheres were prepared with well spherical symmetry, uniform thickness and surface smoothness under 500 nm. The speed of the gold depositing was 6 μm · h -1 . (authors)

  6. Radiolabeled microsphere measurements of alveolar bone blood flow in dogs

    International Nuclear Information System (INIS)

    Kaplan, M.L.; Jeffcoat, M.K.; Goldhaber, P.

    1978-01-01

    Radiolabeled microspheres were injected into the left cardiac ventricle in healthy adult dogs to quantify blood in maxillary and mandibular alveolar bone. Heart rate, arterial blood pressure and pulse contour were monitored throughout each experiment. Blood flow in maxillary alveolar bone was more than 30 % greater (p<.001) than in mandibular alveolar bone. Alveolar bone blood flow (mean +- S.D.) measured as ml/min per gram was 0.12 +- .02 in the maxilla compared to 0.09 +- .02 in the mandible. The cardiovascular parameters monitored were constant immediately prior to the injection of microspheres and remained unchanged during and following injection. It is possible that radiolabeled microspheres can be used to quantify the circulatory changes in alveolar bone during the development of destructive periodontal disease in dogs. (author)

  7. CEBAF: Accelerating cavities look good

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1990-09-15

    The first assembled pairs of superconducting accelerating cavities from German supplier Interatom for the Continuous Electron Beam Accelerator Facility, Newport News, Virginia, have exceeded performance specifications.

  8. CEBAF: Accelerating cavities look good

    International Nuclear Information System (INIS)

    Anon.

    1990-01-01

    The first assembled pairs of superconducting accelerating cavities from German supplier Interatom for the Continuous Electron Beam Accelerator Facility, Newport News, Virginia, have exceeded performance specifications

  9. Fracture properties and heat resistance of ceramics consisting of microspheres of stabilized zirconium dioxide

    International Nuclear Information System (INIS)

    Krasulin, Yu.L.; Barinov, S.M.; Ivanov, A.B.; Timofeev, V.N.; Grevtsev, S.N.; Ivanov, D.A.

    1980-01-01

    Determined were effective specific fracture work, critical coefficient of stress intensity in the upper point of the fracture, strength and heat resistance during heat changes (20-1300 deg C) of the material produced by sintering stabilized zirconium dioxide microspheres. Dependence of these characteristics on granulometric composition of microspheres was determined. It was ascertained that the additional introduction of large microspheres into the bulk of small microspheres increased the metal fracture work. Specific work of material fracture progress exceeded specific work of fracture motion initiation. High value of fracture work together with high strength permits to use the material formed of microspheres as structural ceramics

  10. Temperature influence in crystallinity of polymer microspheres; Influencia da temperatura na cristalinidade de microesferas polimericas

    Energy Technology Data Exchange (ETDEWEB)

    Rezende, Cristiane de P.; Novack, Katia M., E-mail: knovack@iceb.ufop.br [Universidade Federal de Ouro Preto - UFOP, ICEB, DEQUI, Ouro Preto, MG (Brazil)

    2011-07-01

    Drug delivery technology is evolving through the creation of new techniques of drug delivery effectively. The new methods used in drugs administration are based in microencapsulation process. Microsphere encapsulation modifies drug delivery bringing benefits and efficiency. In this work has been evaluated the influence of temperature in microspheres preparation. Microspheres were obtained by PMMA-co-PEG (COP) copolymer with indomethacin inserted in polymer matrix. Samples were characterized by SEM, DSC and XRD. SEM micrographs confirmed the formation of different sizes of microspheres and it was verified that higher temperatures make more crystalline microspheres. (author)

  11. Cephradin-plaga microspheres for sustained delivery to cattle.

    Science.gov (United States)

    Ustariz-Peyret, C; Coudane, J; Vert, M; Kaltsatos, V; Boisramé, B

    1999-01-01

    In the field of controlled drug delivery, most of the reported work is aimed at introducing new systems, or at providing basic information on the critical parameters which affect release profiles in vitro and occasionally in vivo. The situation is totally different when one wants to fulfil the specific requirements imposed by the marketing of a sustained release device to be used in humans or in animals eaten by human beings. The control of the release characteristics is then a difficult challenge. In this work, attempts were made to combine cephradin, a hydrophilic beta-lactam antibiotic, and bioresorbable polymeric matrices of a poly(alpha-hydroxy acid) in the form of microspheres with the aim of delivering the antibiotic to cattle at a dose rate of 4-5 mg/kg/day over a 3-4 days period after i.m. injection. PLAGA aliphatic polyesters were selected because they are already FDA approved as matrices. The solvent evaporation technique using PVA as the emulsion stabilizer was selected because it is efficient and can be extended to an industrial scale. Various experimental conditions were used in order to obtain the highest encapsulation yields compatible with the desired specifications. Decreasing the volume of the aqueous phase and adding a water-miscible organic solvent/non-solvent of cephradin failed. In contrast, microspheres containing up to 30% cephradin were prepared after addition of sodium chloride to the aqueous dispersing phase. The amount of entrapped drug was raised to 40% by decreasing the temperature and the pressure. Preliminary investigations using dogs showed that 20% cephradin microspheres prepared under these conditions extended the presence of cephradin in the blood circulation up to 48 h. Increasing the load led to higher blood concentrations but shorter sustained release. The fact that the microspheres were for cattle limited the volume of the injection and thus the amount of microspheres to be administered. The other limiting factors were

  12. Use of molecular beams to support microspheres during plasma coating

    International Nuclear Information System (INIS)

    Crane, J.K.; Smith, R.D.; Johnson, W.L.; Letts, S.A.; Korbel, G.R.; Krenick, R.M.

    1980-01-01

    Spherical laser fusion targets can be levitated on beams of Ar or other gas atoms. This is an especially useful and reliable technique for supporting microspheres during plasma coating or plasma etching. The reliability of this technique is principally the result of two things: the success of a special centering device which provides a lateral, stabilizing force on the levitated microspheres; and a gas handling system which is capable of controlling levitation gas flow in the microtorr liter/sec range. We have determined that the operational regime of this device is that of Knudsen's flow. This knowledge of the flow characteristics has been important in developing this device

  13. Oxaliplatin loaded PLAGA microspheres: design of specific release profiles.

    Science.gov (United States)

    Lagarce, F; Cruaud, O; Deuschel, C; Bayssas, M; Griffon-Etienne, G; Benoit, J

    2002-08-21

    Oxaliplatin loaded PLAGA microspheres have been prepared by solvent extraction process. Parameters affecting the release kinetics in vitro have been studied in order to design specific release profiles suitable for direct intra-tumoral injection. By varying the nature and the relative proportions of different polymers we managed to prepare microspheres with good encapsulation efficiency (75-90%) and four different release profiles: zero order kinetics (type II) and the classical sigmoïd release profile with three different sizes of plateau and burst. These results, if correlated with in vivo activity, are promising to enhance effectiveness of local tumor treatment.

  14. UO2 microspheres obtainment through the internal gelation methods

    International Nuclear Information System (INIS)

    Sterba, M.E.; Gomez Constenla, A.

    1987-01-01

    UO 2 microspheres obtainment process through the internal gelation method which allows the spheres' obtainment of uniform size is detailed herein, varying the same among 0.3 and 1.7 mm of diameter. The sintered density reaches 10.78 g/cm 3 , permitting the fuels fabrication dispersed and vibro-compacted fuels. The trichloroethylene use implementation as gelation agent is described, thus reducing the number of stages in the microspheres fabrication. At the same time, the uranium sun composition has been modified so as to be compatible with the use solvent. (Author)

  15. Optical diffraction by ordered 2D arrays of silica microspheres

    Science.gov (United States)

    Shcherbakov, A. A.; Shavdina, O.; Tishchenko, A. V.; Veillas, C.; Verrier, I.; Dellea, O.; Jourlin, Y.

    2017-03-01

    The article presents experimental and theoretical studies of angular dependent diffraction properties of 2D monolayer arrays of silica microspheres. High-quality large area defect-free monolayers of 1 μm diameter silica microspheres were deposited by the Langmuir-Blodgett technique under an accurate optical control. Measured angular dependencies of zeroth and one of the first order diffraction efficiencies produced by deposited samples were simulated by the rigorous Generalized Source Method taking into account particle size dispersion and lattice nonideality.

  16. Excitation of resonances of microspheres on an optical fiber

    Science.gov (United States)

    Serpengüzel, A.; Arnold, S.; Griffel, G.

    1995-04-01

    Morphology-dependent resonances (MDR's) of solid microspheres are excited by using an optical fiber coupler. The narrowest measured MDR linewidths are limited by the excitation laser linewidth ( < 0.025 nm). Only MDR's, with an on-resonance to off-resonance intensity ratio of 104, contribute to scattering. The intensity of various resonance orders is understood by the localization principle and the recently developed generalized Lorentz-Mie theory. The microsphere fiber system has potential for becoming a building block in dispersive microphotonics. The basic physics underlying our approach may be considered a harbinger for the coupling of active photonic microstructures such as microdisk lasers.

  17. Controlled Synthesis of Hierarchically Assembled Porous ZnO Microspheres with Enhanced Gas-Sensing Properties

    Directory of Open Access Journals (Sweden)

    Shengsheng You

    2015-01-01

    Full Text Available The ZnO microspheres constructed by porous nanosheets were successfully synthesized by calcinating zinc hydroxide carbonate (ZHC microspheres obtained by a sample hydrothermal method. The samples were characterized in detail with scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, and thermogravimetric and differential scanning calorimetry (TG-DSC. The results indicated that the prepared ZnO microspheres were well crystalline with wurtzite hexagonal phase. The effects of reaction time, temperature, the amount of trisodium citrate, and urea on the morphology of ZnO microspheres were studied. The formation mechanism of porous ZnO microspheres was discussed. Furthermore, the gas-sensing properties for detection of organic gas of the prepared porous ZnO microspheres were investigated. The results indicated that the prepared porous ZnO microspheres exhibited high gas-sensing properties for detection of ethanol gas.

  18. Modified composite microspheres of hydroxyapatite and poly(lactide-co-glycolide) as an injectable scaffold

    International Nuclear Information System (INIS)

    Hu, Xixue; Shen, Hong; Yang, Fei; Liang, Xinjie; Wang, Shenguo; Wu, Decheng

    2014-01-01

    The compound of hydroxyapatite-poly(lactide-co-glycolide) (HA-PLGA) was prepared by ionic bond between HA and PLGA. HA-PLGA was more stable than the simple physical blend of hydroxyapatite and poly(lactide-co-glycolide) (HA/PLGA). The surface of HA-PLGA microsphere fabricated by an emulsion–solvent evaporation method was rougher than that of HA/PLGA microspheres. Moreover, surface HA content of HA-PLGA microspheres was more than that of HA/PLGA microspheres. In vitro mouse OCT-1 osteoblast-like cell culture results showed that the HA-PLGA microspheres clearly promoted osteoblast attachment, proliferation and alkaline phosphatase activity. It was considered that surface rich HA component and rough surface of HA-PLGA microsphere enhanced cell growth and differentiation. The good cell affinity of the HA-PLGA microspheres indicated that they could be used as an injectable scaffold for bone tissue engineering.

  19. Modified composite microspheres of hydroxyapatite and poly(lactide-co-glycolide) as an injectable scaffold

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Xixue [BNLMS, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing 100190 (China); Shen, Hong, E-mail: shenhong516@iccas.ac.cn [BNLMS, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Fei [BNLMS, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Liang, Xinjie [CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing 100190 (China); Wang, Shenguo, E-mail: wangsg@iccas.ac.cn [BNLMS, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Wu, Decheng, E-mail: dcwu@iccas.ac.cn [BNLMS, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-02-15

    The compound of hydroxyapatite-poly(lactide-co-glycolide) (HA-PLGA) was prepared by ionic bond between HA and PLGA. HA-PLGA was more stable than the simple physical blend of hydroxyapatite and poly(lactide-co-glycolide) (HA/PLGA). The surface of HA-PLGA microsphere fabricated by an emulsion–solvent evaporation method was rougher than that of HA/PLGA microspheres. Moreover, surface HA content of HA-PLGA microspheres was more than that of HA/PLGA microspheres. In vitro mouse OCT-1 osteoblast-like cell culture results showed that the HA-PLGA microspheres clearly promoted osteoblast attachment, proliferation and alkaline phosphatase activity. It was considered that surface rich HA component and rough surface of HA-PLGA microsphere enhanced cell growth and differentiation. The good cell affinity of the HA-PLGA microspheres indicated that they could be used as an injectable scaffold for bone tissue engineering.

  20. Li and Na storage behavior of bowl-like hollow Co3O4 microspheres as an anode material for lithium-ion and sodium-ion batteries

    International Nuclear Information System (INIS)

    Wen, Jian-Wu; Zhang, Da-Wei; Zang, Yong; Sun, Xin; Cheng, Bin; Ding, Chu-Xiong; Yu, Yan; Chen, Chun-Hua

    2014-01-01

    Highlights: • A unique bowl-like hollow spherical Co 3 O 4 structure is prepared through a simple, low-cost and mass-yield method. • Such a bowl-like hollow Co 3 O 4 microsphere demonstrates extraordinary rate and cycling performance for Li-storage. • The sodium-storage behavior of Co 3 O 4 is investigated for the first time. - Abstract: Bowl-like hollow Co 3 O 4 microspheres are prepared via a simple and low-cost route by thermally treating Co-containing resorcinol-formaldehyde composites gel in air. Scanning electron microscopy, transmission electron microscope and N 2 adsorption-desorption measurements demonstrate that these bowl-like hollow Co 3 O 4 microspheres are composed of hollow inner cavities and outer shell walls (70 nm thickness), on which a considerable amount of mesopores centered around 5-17 nm size are distributed. When employed as the anode material for lithium-ion batteries, these bowl-like hollow Co 3 O 4 microspheres exhibit extraordinary cycling performance (111% retention after 50 cycles owing to capacity rise), fairly high rate capacity (650 mAh g −1 at 5 C) and enhanced lithium storage capacity. Meanwhile, the Na-storage behavior of Co 3 O 4 as an anode material of Na-ion batteries is initially investigated based on such a hollow structure and it exhibits similar feature of discharge/charge profiles and a high initial discharge capacity but relatively moderate capacity retention compared with the Li-storage performance

  1. Evaluation of nonradioactive, colored microspheres for measurement of regional myocardial blood flow in dogs

    International Nuclear Information System (INIS)

    Hale, S.L.; Alker, K.J.; Kloner, R.A.

    1988-01-01

    Measurement of regional myocardial blood flow (RMBF) is crucial in experimental studies of myocardial ischemia and reperfusion in dogs. The standard measurement technique uses radioactive microspheres; however, not all institutions are able to dispose of radioactive waste and therefore cannot make use of this method. We tested a new, nonradioactive microsphere, labeled with colors instead of nuclides. Simultaneous blood flow measurements with two nuclide-labeled and two colored microspheres were performed after coronary occlusion in dogs. Both techniques show a within-method correlation of r greater than 0.98. Duplicate variability for paired RMBF values in 80 samples was 8.7 +/- 0.1% when computed with radioactive microspheres and 13.2 +/- 1.8% when computed with colored microspheres. There was a good correlation in the measurement of RMBF between the radioactive- and colored-microsphere methods (r = 0.98). The best-fitting linear regression line was expressed by the formula: Colored-microsphere RMBF = 1.11 (radioactive-microsphere RMBF)-0.02. When measured by colored microspheres, RMBF was approximately 8% higher than when computed with radioactive microspheres for blood flow values of 0-2 ml/min/g. When blood flow was increased pharmacologically to levels of 2-7.5 ml/min/g, colored microspheres yielded blood flow values 39% higher than the values computed by radioactive microspheres. We conclude that the nonradioactive, colored-microsphere method correlates with the radioactive technique, but at high flows, it yields values greater than those obtained with radioactive microspheres

  2. Surface modification of cyclomatrix polyphosphazene microsphere by thiol-ene chemistry and lectin recognition

    International Nuclear Information System (INIS)

    Chen, Chen; Zhu, Xue-yan; Gao, Qiao-ling; Fang, Fei; Huang, Xiao-jun

    2016-01-01

    Graphical abstract: A new synthetic route leading to polyphosphazene cyclomatrix microsphere with various functional groups has achieved via thiol-ene click modification. Herein, hexacholorocyclophosphazene (HCCP) crosslinked with bisphenol-S and 4,4′-diallyl bisphenol-S to generate broadly dispersed microspheres. Thiol-ene modification under UV irradiation not only presented high efficiency and flexibility for post-functionalization, but also imposed no harm on global morphology and crosslinked skeleton of such microspheres. - Highlights: • Functional polyphosphazene microspheres with high chemical flexibility were synthesized by thiol-ene modification. • Polyphosphazene microspheres possessed high thermal stability. • Glycosylated polyphosphazene microspheres showed affinity to lectin Con-A, which inferred potential application in biomedicine. - Abstract: A new synthetic route leading to functional polyphosphazene cyclomatrix microsphere has been developed via thiol-ene click modification. Hexacholorocyclophosphazene (HCCP) was crosslinked with both bisphenol-S and 4,4′-diallyl bisphenol-S to obtain vinyl polyphosphazene microspheres (VPZM) in order to ensure high crosslinking degree and introduce vinyl moieties. Compared to the microspheres obtained by HCCP and bisphenol-S, the size of VPZM was broadly dispersed from 400 nm to 1.40 μm. Thiol-ene click reactions were carried out to attach functional groups, such as glucosyl, carboxyl, ester and dodecyl groups onto polyphosphazene microspheres, which demonstrated no change in morphology and size after modification. Solid state NMR (SSNMR) and Fourier transform infrared spectoscopy (FT-IR) results showed that the vinyl moieties were introduced in the period of crosslinking and functionalization was also successful via click reactions. Moreover, the microspheres presented a little difference in thermal properties after modification. Concanavalin A (Con-A) fluorescent adsorption was also observed for

  3. Polymer based microspheres of aceclofenac as sustained release parenterals for prolonged anti-inflammatory effect

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Manpreet; Sharma, Sumit; Sinha, VR, E-mail: sinha_vr@rediffmail.com

    2017-03-01

    Poly(lactic-co-glycolic acid) (PLGA) (75:25) and polycaprolactone (PCL) microspheres were fabricated for prolonged release of aceclofenac by parenteral administration. Microspheres encapsulating aceclofenac were designed to release the drug at controlled rate for around one month. Biodegradable microspheres were prepared by solvent emulsification evaporation method in different polymer:drug ratios (1:1, 2:1 and 3:1). After drug loading, PLGA and PCL microspheres showed a controlled size distribution with an average size of 11.75 μm and 3.81 μm respectively and entrapment efficiency in the range of 90 ± 0.72% to 91.06 ± 4.01% with PLGA and 83.01 ± 2.13% to 90.4 ± 2.11% with PCL. Scanning electron microscopy has confirmed good spherical structures of microspheres. The percent yield of biodegradable polymeric microspheres ranged between 30.95 ± 10.14% to 92.84 ± 3.15% and 47.33 ± 4.72% to 80 ± 3.60% for PLGA and PCL microspheres respectively. PLGA microspheres followed Higuchi release pattern while Korsmeyer-Peppas explained the release pattern of PCL microspheres. Stability studies of microspheres were also carried out by storing the preparations at 2-8 °C for 30, 60 and 90 days and evaluating them for entrapment efficiency, residual drug content and polymer drug compatability. In-vivo studies showed significant anti-inflammatory activity of microspheres upto 48 hours using the carrageenan induced rat paw oedema model. - Highlights: • PLGA and PCL polymeric microspheres for parenteral prolonged drug delivery system were formulated. • Polymeric microspheres were characterized physically and drug excipient incompatability. • Three months accelerated stability studies were carried for drug loaded polymeric microspheres. • Pharmacodynamic studies prove the rationality of sustained therapeutic effect of designed drug delivery system.

  4. Surface modification of cyclomatrix polyphosphazene microsphere by thiol-ene chemistry and lectin recognition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen; Zhu, Xue-yan; Gao, Qiao-ling; Fang, Fei; Huang, Xiao-jun, E-mail: hxjzxh@zju.edu.cn

    2016-11-30

    Graphical abstract: A new synthetic route leading to polyphosphazene cyclomatrix microsphere with various functional groups has achieved via thiol-ene click modification. Herein, hexacholorocyclophosphazene (HCCP) crosslinked with bisphenol-S and 4,4′-diallyl bisphenol-S to generate broadly dispersed microspheres. Thiol-ene modification under UV irradiation not only presented high efficiency and flexibility for post-functionalization, but also imposed no harm on global morphology and crosslinked skeleton of such microspheres. - Highlights: • Functional polyphosphazene microspheres with high chemical flexibility were synthesized by thiol-ene modification. • Polyphosphazene microspheres possessed high thermal stability. • Glycosylated polyphosphazene microspheres showed affinity to lectin Con-A, which inferred potential application in biomedicine. - Abstract: A new synthetic route leading to functional polyphosphazene cyclomatrix microsphere has been developed via thiol-ene click modification. Hexacholorocyclophosphazene (HCCP) was crosslinked with both bisphenol-S and 4,4′-diallyl bisphenol-S to obtain vinyl polyphosphazene microspheres (VPZM) in order to ensure high crosslinking degree and introduce vinyl moieties. Compared to the microspheres obtained by HCCP and bisphenol-S, the size of VPZM was broadly dispersed from 400 nm to 1.40 μm. Thiol-ene click reactions were carried out to attach functional groups, such as glucosyl, carboxyl, ester and dodecyl groups onto polyphosphazene microspheres, which demonstrated no change in morphology and size after modification. Solid state NMR (SSNMR) and Fourier transform infrared spectoscopy (FT-IR) results showed that the vinyl moieties were introduced in the period of crosslinking and functionalization was also successful via click reactions. Moreover, the microspheres presented a little difference in thermal properties after modification. Concanavalin A (Con-A) fluorescent adsorption was also observed for

  5. Perfusion measurements with radioactively labelled microspheres

    International Nuclear Information System (INIS)

    Schosser, R.

    1980-01-01

    The technique and the evaluation of the microsphere-method are comprehensively represented in theory and practice. Some changes and new concepts are discussed, besides the known foundations and techniques, that assure an essential methodic improvement resp. practical simplifications. Two new formulas are derived within the frame of the theoretical principles, by which the absolute flux of shorts can be calculated, i.e. on the one hand in the case of known and on the other hand in the case of unknown applied amount of indicator. The determination of the optimal indicator dose is defined and formulated mathematically with respect to the experimental conditions to be expected. The matrix method was designed for the analysis of complex gamma spectra. Hereby there is no selective error accumulation in the case of low energy radio nuclids contrary to the so far exclusively used stripping technique. The number of possible error quantities was reduced by one resp. two variables. The error of particular radio nuclid components is quantitatively computed as standard deviation by means of the theory of approximated systems of linear equations. The external measurement of distance was developed. This technique is less susceptible for errors as the aliquota i.e. whole body measurement technique. Additionally less measurement time is needed. A flexible computer program for a desk top computer was developped for the evaluation. The data from the gamma spectrometer are recorded on tipe and automatically read in by the computer. The manual input are limited to the weights of the organs and some control parameter. The output is made by a clearly arranged table by means of a lineprinter. (orig./MG) [de

  6. Single and Coupled Nanobeam Cavities

    DEFF Research Database (Denmark)

    Ivinskaya, Aliaksandra; Lavrinenko, Andrei; Shyroki, Dzmitry M.

    2013-01-01

    for analysis and design of photonic crystal devices, such as 2D ring resonators for filters, single and coupled nanobeam cavities, birefringence in photonic crystal cavities, threshold analysis in photonic crystal lasers, gap solitons in photonic crystals, novel photonic atolls, dynamic characteristics...

  7. Technical tasks in superconducting cavities

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Kenji [High Energy Accelerator Research Organization, Tsukuba, Ibaraki (Japan)

    1997-11-01

    The feature of superconducting rf cavities is an extremely small surface resistance on the wall. It brings a large energy saving in the operation, even those are cooled with liquid helium. That also makes possible to operate themselves in a higher field gradient comparing to normal conducting cavities, and brings to make accelerators compact. These merits are very important for the future accelerator engineering which is planed at JAERI for the neutron material science and nuclear waste transmutation. This machine is a high intensity proton linac and uses sc cavities in the medium and high {beta} sections. In this paper, starting R and D of proton superconducting cavities, several important technical points which come from the small surface resistance of sc cavities, are present to succeed it and also differences between the medium and high - {beta} structures are discussed. (author)

  8. Pacer processing: cavity inventory relationships

    International Nuclear Information System (INIS)

    Dietz, R.J.; Gritzo, L.A.

    1975-09-01

    The pacer cavity and its associated primary power loop comprise a recirculating system in which materials are introduced by a series of thermonuclear explosions while debris is continuously removed by radioactive decay, sorption phenomena, and deliberate processing. Safe, reliable, and economical realization of the Pacer concept depends on the removal and control of both noxious and valuable by-products of the fusion reaction. Mathematical relationships are developed that describe the quantities of materials that are introduced into the Pacer cavity by a series of discrete events and are removed continuously by processing and decay. An iterative computer program based on these relationships is developed that allows both the total cavity inventory and the amounts of important individual species to be determined at any time during the lifetime of the cavity in order to establish the effects of the thermonuclear event, the cavity, the flow, and various processing parameters on Pacer design requirements

  9. On a possibility of using a superconducting cavity in the RF system of the storage ring LESR-N100

    CERN Document Server

    Androsov, V P; Telegin, Yu P

    2002-01-01

    In the Kharkov Institute of Physics and Technology the design project of the 200 MeV electron storage ring LESR-N100 is under development. The essential feature of this facility is the large beam energy spread (of about 1%). To ensure a reasonable beam lifetime the RF-system should provide the accelerating voltage of about 0.5 MV, while the total energy losses do not exceed approx 700 eV/turn. The power dissipated in two 700 MHz normal-conducting (NC) cavities much exceeds the power transmitted to the beam. We considered a possibility to use in LESR-N100 a high-Q superconducting RF-cavity (SRF-cavity) in which the dissipated power is the same order of magnitude as the beam-transmitted power. The studies show that the system with SRF-cavity cannot operate in the standard mode when the cavity is matched to the power transmission line at some nominal beam current. The optimal operation mode with high overcoupling is proposed that requires the RF-power one order of magnitude less than in the case of Nc-cavities.

  10. Recombinant Gelatin Microspheres : Novel Formulations for Tissue Repair?

    NARCIS (Netherlands)

    Tuin, Annemarie; Kluijtmans, Sebastiaan G.; Bouwstra, Jan B.; Harmsen, Martin C.; Van Luyn, Marja J. A.

    Microspheres (MSs) can function as multifunctional scaffolds in different approaches of tissue repair (TR), as a filler, a slow-release depot for growth factors, or a delivery vehicle for cells. Natural cell adhesion-supporting extracellular matrix components like gelatin are good materials for

  11. Use of molecular beams to support microspheres during plasma coating

    International Nuclear Information System (INIS)

    Crane, J.K.; Smith, R.D.; Johnson, W.L.; Jordan, C.W.; Letts, S.A.; Korbel, G.R.; Krenik, R.M.

    1980-01-01

    Spherical targets can be levitated on beams of Ar or other gas atoms. This is an especially useful technique for supporting microspheres during plasma coating and processing. Measurements of gas flow and pressure indicate that the levitation device operates in the regime of Knudsen's flow. This device is currently being used in the development of future generation laser targets

  12. Albumin-heparin microspheres as carriers for cytostatic agents

    NARCIS (Netherlands)

    Cremers, Harry; Feijen, Jan; Kwon, G.; Bae, Y.H.; Kim, S.W.; Noteborn, H.P.J.M.; Mcvie, J.G.

    1990-01-01

    Much work has been done on adriamycin-loaded albumin microspheres (Alb-MS) for chemoembolization [1–4], the rationale being that site-specific drug delivery may increase the therapeutic efficacy of the drug. Alb-Ms are being investigated because of their biocompatibility and because the degradation

  13. Fabrication of periodically ordered diamond nanostructures by microsphere lithography

    Czech Academy of Sciences Publication Activity Database

    Domonkos, Mária; Ižák, Tibor; Štolcová, L.; Proška, J.; Kromka, Alexander

    2014-01-01

    Roč. 251, č. 12 (2014), s. 2587-2592 ISSN 0370-1972 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:68378271 Keywords : CVD growth * diamond * microsphere lithography * selective area deposition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.489, year: 2014

  14. loaded Eudragit RL 100 Microspheres Prepared by an Emulsion

    African Journals Online (AJOL)

    Erah

    drug release profiles of the microspheres at pH 1.2 showed poor drug release characteristics while at. pH 6.8 ... drug delivery, improve bioavailability and stability and target drug to ... The factors affecting particle size, drug loading and drug.

  15. BIOCOMPATIBLE FLUORESCENT MICROSPHERES: SAFE PARTICLES FOR MATERIAL PENETRATION STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    farquar, G; Leif, R

    2008-09-12

    Biocompatible polymers with hydrolyzable chemical bonds are being used to produce safe, non-toxic fluorescent microspheres for material penetration studies. The selection of polymeric materials depends on both biocompatibility and processability, with tailored fluorescent properties depending on specific applications. Microspheres are composed of USFDA-approved biodegradable polymers and non-toxic fluorophores and are therefore suitable for tests where human exposure is possible. Micropheres are being produced which contain unique fluorophores to enable discrimination from background aerosol particles. Characteristics that affect dispersion and adhesion can be modified depending on use. Several different microsphere preparation methods are possible, including the use of a vibrating orifice aerosol generator (VOAG), a Sono-Tek atomizer, an emulsion technique, and inkjet printhead. The advantages and disadvantages of each method will be presented and discussed in greater detail along with fluorescent and charge properties of the aerosols. Applications for the fluorescent microspheres include challenges for biodefense system testing, calibrants for biofluorescence sensors, and particles for air dispersion model validation studies.

  16. Biotemplate synthesis of monodispersed iron phosphate hollow microspheres

    International Nuclear Information System (INIS)

    Cao Feng; Li Dongxu

    2010-01-01

    Monodispersed iron phosphate hollow microspheres with a high degree of crystallization were prepared through a facile in situ deposition method using rape pollen grains as a biotemplate. The functional group on the surface of the pollen grains could adsorb Fe 3+ , which provided the nucleation sites for growth of iron phosphate nanoparticles. After being sintered at 600 deg. C for 10 h, the pollen grains were removed and iron phosphate hollow microspheres were obtained. A scanning electron microscope and x-ray diffraction were applied to characterize the morphology and crystalline structure of the pollen grains, iron phosphate-coated pollen grains and iron phosphate hollow microspheres. Differential scanning calorimetry and thermogravity analyses were performed to investigate the thermal behavior of the iron phosphate-coated pollen grains during the calcinations. Energy dispersive spectroscopy and Fourier transform infrared spectroscopy were utilized to investigate the interaction between the pollen grains and iron phosphate. The effect of the pollen wall on the surface morphology of these iron phosphate hollow microspheres was also proven in this work.

  17. Biotemplate synthesis of monodispersed iron phosphate hollow microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Cao Feng; Li Dongxu, E-mail: dongxuli@njut.edu.c [College of Materials Science and Engineering, Nanjing University of Technology, Jiangsu Nanjing 210009 (China)

    2010-03-15

    Monodispersed iron phosphate hollow microspheres with a high degree of crystallization were prepared through a facile in situ deposition method using rape pollen grains as a biotemplate. The functional group on the surface of the pollen grains could adsorb Fe{sup 3+}, which provided the nucleation sites for growth of iron phosphate nanoparticles. After being sintered at 600 deg. C for 10 h, the pollen grains were removed and iron phosphate hollow microspheres were obtained. A scanning electron microscope and x-ray diffraction were applied to characterize the morphology and crystalline structure of the pollen grains, iron phosphate-coated pollen grains and iron phosphate hollow microspheres. Differential scanning calorimetry and thermogravity analyses were performed to investigate the thermal behavior of the iron phosphate-coated pollen grains during the calcinations. Energy dispersive spectroscopy and Fourier transform infrared spectroscopy were utilized to investigate the interaction between the pollen grains and iron phosphate. The effect of the pollen wall on the surface morphology of these iron phosphate hollow microspheres was also proven in this work.

  18. Hollow microspheres with a tungsten carbide kernel for PEMFC application.

    Science.gov (United States)

    d'Arbigny, Julien Bernard; Taillades, Gilles; Marrony, Mathieu; Jones, Deborah J; Rozière, Jacques

    2011-07-28

    Tungsten carbide microspheres comprising an outer shell and a compact kernel prepared by a simple hydrothermal method exhibit very high surface area promoting a high dispersion of platinum nanoparticles, and an exceptionally high electrochemically active surface area (EAS) stability compared to the usual Pt/C electrocatalysts used for PEMFC application.

  19. Processing and Characterization of Sol-Gel Cerium Oxide Microspheres

    Energy Technology Data Exchange (ETDEWEB)

    McClure, Zachary D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Padilla Cintron, Cristina [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-09-27

    Of interest to space exploration and power generation, Radioisotope Thermoelectric Generators (RTGs) can provide long-term power to remote electronic systems without the need for refueling or replacement. Plutonium-238 (Pu-238) remains one of the more promising materials for thermoelectric power generation due to its high power density, long half-life, and low gamma emissions. Traditional methods for processing Pu-238 include ball milling irregular precipitated powders before pressing and sintering into a dense pellet. The resulting submicron particulates of Pu-238 quickly accumulate and contaminate glove boxes. An alternative and dust-free method for Pu-238 processing is internal gelation via sol-gel techniques. Sol-gel methodology creates monodisperse and uniform microspheres that can be packed and pressed into a pellet. For this study cerium oxide microspheres were produced as a surrogate to Pu-238. The similar electronic orbitals between cerium and plutonium make cerium an ideal choice for non-radioactive work. Before the microspheres can be sintered and pressed they must be washed to remove the processing oil and any unreacted substituents. An investigation was performed on the washing step to find an appropriate wash solution that reduced waste and flammable risk. Cerium oxide microspheres were processed, washed, and characterized to determine the effectiveness of the new wash solution.

  20. Preparation and Characterization of Sugar Cane Wax Microspheres ...

    African Journals Online (AJOL)

    HP

    scanning calorimetry (DSC) as well as for drug loading, and in vitro and in vivo release in albino sheeps. Results: SEM images .... Rolex, India), and the sphericity factor (S) was calculated using ... using a fully validated high performance liquid ... Pharmacokinetic and data analysis ... microspheres exerts an influence on the.

  1. Preparation and Characterization of Colon-Specific Microspheres of ...

    African Journals Online (AJOL)

    Purpose: To prepare and evaluate colon specific drug delivery system of diclofenac sodium for highly localized delivery to the colon. Methods: The colon specific drug delivery system was prepared as matrix-type microspheres using Ethyl Cellulose (EC), Cellulose Acetate Phthalate (CAP), and Eudragit L 100-55 by the ...

  2. Method for forming microspheres for encapsulation of nuclear waste

    Science.gov (United States)

    Angelini, Peter; Caputo, Anthony J.; Hutchens, Richard E.; Lackey, Walter J.; Stinton, David P.

    1984-01-01

    Microspheres for nuclear waste storage are formed by gelling droplets containing the waste in a gelation fluid, transferring the gelled droplets to a furnace without the washing step previously used, and heating the unwashed gelled droplets in the furnace under temperature or humidity conditions that result in a substantially linear rate of removal of volatile components therefrom.

  3. Formulation and evaluation of matrix microspheres for simultaneous ...

    African Journals Online (AJOL)

    The prepared microspheres were characterized for their micromeritic properties and drug loading, as well as by infrared spectroscopy (IR), differential scanning calorimetry (DSC), x-ray powder diffractometry (XRD) and scanning electron microscopy (SEM). The in vitro release studies were performed in pH 7.4, phosphate ...

  4. Mucoadhesive microspheres: a promising tool in drug delivery.

    Science.gov (United States)

    Patil, Sanjay B; Sawant, Krutika K

    2008-10-01

    Mucoadhesive polymers have recently gained interest among pharmaceutical scientists as a means of improving drug delivery by promoting the residence time and contact time of the dosage form with the mucous membranes. Mucoadhesion is the process whereby synthetic and natural polymers adhere to mucosal surfaces in the body. If these materials are then incorporated into pharmaceutical formulations, drug absorption by mucosal cells may be enhanced or the drug will be released at the site for an extended period of time. Microspheres, in general, have the potential to be used for targeted and controlled release drug delivery; however, coupling of mucoadhesive properties to microspheres has additional advantages like, a much more intimate contact with the mucus layer, efficient absorption and enhanced bioavailability of the drugs due to a high surface to volume ratio. The present review describes the potential applications of mucoadhesive microspheres as a novel carrier system to improve drug delivery by various routes of administration like buccal, oral, nasal, ocular, vaginal and rectal, either for systemic or for local effects. The mucoadhesive polymers, methods of preparation of microspheres and their in vitro and in vivo evaluation are also described.

  5. Calcium carbonate microspheres as carriers for the anticancer drug camptothecin

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Neng [Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8LT (United Kingdom); State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Department of Bio-pharmaceutical Engineering, School of Chemical Engineering, Sichuan University, Chengdu ,610065 (China); Yin, Huabing, E-mail: huabing.yin@glasgow.ac.uk [Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8LT (United Kingdom); Ji, Bozhi; Klauke, Norbert; Glidle, Andrew [Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, G12 8LT (United Kingdom); Zhang, Yongkui; Song, Hang [Department of Bio-pharmaceutical Engineering, School of Chemical Engineering, Sichuan University, Chengdu ,610065 (China); Cai, Lulu; Ma, Liang; Wang, Guangcheng [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Chen, Lijuan, E-mail: lijuan17@hotmail.com [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China); Wang, Wenwen [State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041 (China)

    2012-12-01

    Biogenic calcium carbonate has come to the attention of many researchers as a promising drug delivery system due to its safety, pH sensitivity and the large volume of information already in existence on its medical use. In this study, we employed bovine serum albumin (BSA) as an additive to synthesize a series of porous calcium carbonate microspheres (CCMS). These spheres, identified as vaterite, are stable both in aqueous solutions and organic solvents. Camptothecin, an effective anticancer agent, was loaded into the CCMS by simple diffusion and adsorption. The camptothecin loaded CCMS showed sustained cell growth inhibitory activity and a pH dependent release of camptothecin. With a few hours, the release is negligible under physiological conditions (pH = 7.4) but almost complete at pH 4 to 6 (i.e. pHs found in lysosomes and solid tumor tissue respectively). These findings suggest that porous, biogenic calcium carbonate microspheres could be promising carriers for the safe and efficient delivery of anticancer drugs of low aqueous solubility. - Highlights: Black-Right-Pointing-Pointer BSA-doped calcium carbonate microspheres with porous structure were prepared. Black-Right-Pointing-Pointer Camptothecin was encapsulated in the spherical microparticles with encapsulation efficiency up to 11%. Black-Right-Pointing-Pointer The release of encapsulated camptothecin is pH dependent Black-Right-Pointing-Pointer In vitro studies showed an effective anticancer activity of the camptothecin- microspheres.

  6. Effects of hepatic arterial yttrium 90 glass microspheres in dogs.

    Science.gov (United States)

    Wollner, I; Knutsen, C; Smith, P; Prieskorn, D; Chrisp, C; Andrews, J; Juni, J; Warber, S; Klevering, J; Crudup, J

    1988-04-01

    A 22-micron glass microsphere called TheraSphere (Theragenics Corp., Atlanta, GA) has been developed in which yttrium 89 oxide is incorporated into the glass matrix and is activated by neutron bombardment to form the beta-emitting isotope yttrium 90 (Y 90) before using the spheres as radiotherapeutic vehicles. The injection of up to 12 times (on a liver weight basis) the anticipated human dose of nonradioactive TheraSphere into the hepatic arteries of dogs was well tolerated and produced clinically silent alterations within centrolobular areas. The hepatic arterial (HA) injection of radioactive TheraSphere also produced portal changes similar to those observed in humans after external beam therapy. While the extent of damage increased with the delivered dose, radiation exposures in excess of 30,000 cGy did not cause total hepatic necrosis and were compatible with survival. No microspheres distributed to the bone marrow and absolutely no myelosuppression was encountered in any animal. Proposed hepatic exposures to humans of 5000 to 10,000 cGy by means of these microspheres, therefore, would appear to be feasible and tolerable. Radiotherapeutic microsphere administration preceded by regional infusion of a radiosensitizing agent and/or immediately following the redistribution of blood flow toward intrahepatic tumor by vasoactive agents can potentially yield a synergistic, highly selective attack on tumors confined to the liver.

  7. Formulation and Optimization of Celecoxib-Loaded Microspheres ...

    African Journals Online (AJOL)

    factors in the preparation of celecoxib-loaded microspheres. Methods: ... made with biodegradable polymers, are ... filtration on Whatman filter paper no.1 and washed 4 - 5 times with n-hexane [11]. The product was then air-dried at room.

  8. Preparation and characterization of microspheres of albumin-heparin conjugates

    NARCIS (Netherlands)

    Kwon, Glen S.; Bae, You Han; Kim, Sung Wan; Cremers, Harry; Cremers, H.F.M.; Feijen, Jan

    1991-01-01

    Albumin-heparin microspheres have been prepared as a new drug carrier. A soluble albumin-heparin conjugate was synthesized by forming amide bonds between human serum albumin and heparin. After purification the albumin-heparin conjugate was crosslinked in a water-in-oil emulsion to form

  9. Novel fluorescent poly(glycidyl methacrylate) - silica microspheres

    Czech Academy of Sciences Publication Activity Database

    Grama, Silvia; Boiko, N.; Bilyy, R.; Klyuchivska, O.; Antonyuk, V.; Stoika, R.; Horák, Daniel

    2014-01-01

    Roč. 56, July (2014), s. 92-104 ISSN 0014-3057 R&D Projects: GA MŠk EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : microspheres * silica * poly(glycidyl methacrylate) Subject RIV: CE - Biochemistry Impact factor: 3.005, year: 2014

  10. Fabrication of polystyrene hollow microspheres as laser fusion ...

    Indian Academy of Sciences (India)

    free from preheating problems and have emerged as good alternative to .... carry a system over the energy barrier comes from the Brownian motion of the ... This increase implies an increase in the electrical contribution to the free energy of the .... microsphere is mainly determined by rotational speed of the magnetic stirrer.

  11. Development of activity standard for 90Y microspheres

    CSIR Research Space (South Africa)

    Mo, L

    2005-08-01

    Full Text Available 90Y is a therapeutic radiopharmaceuticals used in the treatment of liver cancer following implantation via a catheter in the hepatic artery, 90Y microspheres are embolised in the microvasculature of liver cancer where they irradiate the tumour by a...

  12. LLRF Control of High Loaded-Q Cavities for the LCLS-II

    Energy Technology Data Exchange (ETDEWEB)

    Serrano, Carlos [LBNL, Berkeley; Babel, Sandeep [SLAC; Bachimanchi, Ramakrishna [Jefferson Lab; Boyes, Matt [SLAC; Chase, Brian [Fermilab; Cullerton, Ed [Fermilab; Doolittle, Lawrence [LBNL, Berkeley; Einstein, Joshua [Fermilab; Hong, Bo [SLAC; Hovater, Curt [Jefferson Lab; Huang, Gang [LBNL, Berkeley; Ratti, Alessandro [LBNL, Berkeley

    2016-06-01

    The SLAC National Accelerator Laboratory is planning an upgrade (LCLS-II) to the Linear Coherent Light Source with a 4 GeV CW Superconducting Radio Frequency (SCRF) linac. The nature of the machine places stringent requirements in the Low-Level RF (LLRF) system, expected to control the cavity fields within 0.01 degrees in phase and 0.01% in amplitude, which is equivalent to a longitudinal motion of the cavity structure in the nanometer range. This stability has been achieved in the past but never for hundreds of superconducting cavities in Continuous-Wave (CW) operation. The difficulty resides in providing the ability to reject disturbances from the cryomodule, which is incompletely known as it depends on the cryomodule structure itself (currently under development at JLab and Fermilab) and the harsh accelerator environment. Previous experience in the field and an extrapolation to the cavity design parameters (relatively high Q_{L}c≈ 4×10⁷ , implying a half-bandwidth of around 16 Hz) suggest the use of strong RF feedback to reject the projected noise disturbances, which in turn demands careful engineering of the entire system.

  13. Single-nanoparticle detection with slot-mode photonic crystal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Cheng; Kita, Shota; Lončar, Marko, E-mail: loncar@seas.harvard.edu [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); Li, Yihang [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China)

    2015-06-29

    Optical cavities that are capable for detecting single nanoparticles could lead to great progress in early stage disease diagnostics and the study of biological interactions on the single-molecule level. In particular, photonic crystal (PhC) cavities are excellent platforms for label-free single-nanoparticle detection, owing to their high quality (Q) factors and wavelength-scale modal volumes. Here, we demonstrate the design and fabrication of a high-Q (>10{sup 4}) slot-mode PhC nanobeam cavity, which is able to strongly confine light in the slotted regions. The enhanced light-matter interaction results in an order of magnitude improvement in both refractive index sensitivity (439 nm/RIU) and single-nanoparticle sensitivity compared with conventional dielectric-mode PhC cavities. Detection of single polystyrene nanoparticles with radii of 20 nm and 30 nm is demonstrated in aqueous environments (D{sub 2}O), without additional laser and temperature stabilization techniques.

  14. Optimization of three-dimensional micropost microcavities for cavity quantum electrodynamics

    International Nuclear Information System (INIS)

    Vuckovic, Jelena; Pelton, Matthew; Scherer, Axel; Yamamoto, Yoshihisa

    2002-01-01

    This paper presents a detailed analysis, based on the first-principles finite-difference time-domain method, of the resonant frequency, quality factor (Q), mode volume (V), and radiation pattern of the fundamental (HE 11 ) mode in a three-dimensional distributed-Bragg-reflector (DBR) micropost microcavity. By treating this structure as a one-dimensional cylindrical photonic crystal containing a single defect, we are able to push the limits of Q/V beyond those achievable by standard micropost designs, based on the simple rules established for planar DBR microcavities. We show that some of the rules that work well for designing large-diameter microposts (e.g., high-refractive-index contrast) fail to provide high-quality cavities with small diameters. By tuning the thicknesses of mirror layers and the spacer, the number of mirror pairs, the refractive indices of high- and low-refractive index regions, and the cavity diameter, we are able to achieve Q as high as 10 4 , together with a mode volume of 1.6 cubic wavelengths of light in the high-refractive-index material. The combination of high Q and small V makes these structures promising candidates for the observation of such cavity-quantum-electrodynamics phenomena as strong coupling between a quantum dot and the cavity field, and single-quantum-dot lasing

  15. Frequency-feedback cavity enhanced spectrometer

    Science.gov (United States)

    Hovde, David Christian; Gomez, Anthony

    2015-08-18

    A spectrometer comprising an optical cavity, a light source capable of producing light at one or more wavelengths transmitted by the cavity and with the light directed at the cavity, a detector and optics positioned to collect light transmitted by the cavity, feedback electronics causing oscillation of amplitude of the optical signal on the detector at a frequency that depends on cavity losses, and a sensor measuring the oscillation frequency to determine the cavity losses.

  16. Nonlocal Intracranial Cavity Extraction

    Science.gov (United States)

    Manjón, José V.; Eskildsen, Simon F.; Coupé, Pierrick; Romero, José E.; Collins, D. Louis; Robles, Montserrat

    2014-01-01

    Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV) is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden. PMID:25328511

  17. Nonlocal Intracranial Cavity Extraction

    Directory of Open Access Journals (Sweden)

    José V. Manjón

    2014-01-01

    Full Text Available Automatic and accurate methods to estimate normalized regional brain volumes from MRI data are valuable tools which may help to obtain an objective diagnosis and followup of many neurological diseases. To estimate such regional brain volumes, the intracranial cavity volume (ICV is often used for normalization. However, the high variability of brain shape and size due to normal intersubject variability, normal changes occurring over the lifespan, and abnormal changes due to disease makes the ICV estimation problem challenging. In this paper, we present a new approach to perform ICV extraction based on the use of a library of prelabeled brain images to capture the large variability of brain shapes. To this end, an improved nonlocal label fusion scheme based on BEaST technique is proposed to increase the accuracy of the ICV estimation. The proposed method is compared with recent state-of-the-art methods and the results demonstrate an improved performance both in terms of accuracy and reproducibility while maintaining a reduced computational burden.

  18. Hollow mesoporous titania microspheres: New technology and enhanced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Zhenliang; Wei, Wenrui; Wang, Litong [School of Chemical Engineering, Fuzhou University, Fuzhou 350108 (China); Hong, Ruoyu, E-mail: rhong@suda.edu.cn [School of Chemical Engineering, Fuzhou University, Fuzhou 350108 (China); College of Chemistry, Chemical Engineering and Materials Science & Key Laboratory of Organic Synthesis of Jiangsu Province, Soochow University, SIP, Suzhou 215123 (China)

    2015-12-01

    Graphical abstract: Schematic of the formation process of HTS. - Highlights: • Amino modified porous PS-DVB microspheres were used as templates to coat TiO{sub 2.} • The coating of TiO{sub 2} was conducted under regular changing atmospheric pressure. • The PS-DVB@TiO{sub 2} was calcinated first under nitrogen and then under air to get HTS. • The resultant products were provided with high surface area and excellent photocatalytic activity under UV irradiation. - Abstract: Hollow titania microspheres (HTS) were fabricated via a sol–gel process by coating the hydrolysis product of titanium tetrabutoxide (TBOT) onto the amino (–NH{sub 2}) modified porous polystyrene cross-linked divinyl benzene (PS-DVB) microspheres under changing atmospheric pressure, followed by calcination in nitrogen and air atmosphere. Particularly, the atmospheric pressure was continuously and regularly changed during the formation process of PS-DVB@TiO{sub 2} microspheres. Then the TiO{sub 2} particles were absorbed into the pores and onto the surface of PS-DVB as well. The resultant HTS (around 2 μm in diameter) featured a high specific surface area (84.37 m{sup 2}/g), anatase crystal and stable hollow microsphere structure, which led to high photocatalysis activity. The photocatalytic degradation of malachite green (MG) organic dye solution was conducted under ultraviolet (UV) light irradiation, which showed a high photocatalytic ability (81% of MG was degraded after UV irradiation for 88 min). Therefore, it could be potentially applied for the treatment of wastewater contaminated by organic pollutants.

  19. Yttrium-90 microspheres for the treatment of hepatocellular carcinoma.

    Science.gov (United States)

    Geschwind, Jean Francois H; Salem, Riad; Carr, Brian I; Soulen, Michael C; Thurston, Kenneth G; Goin, Kathleen A; Van Buskirk, Mark; Roberts, Carol A; Goin, James E

    2004-11-01

    Unresectable hepatocellular carcinoma is extremely difficult to treat. TheraSphere consists of yttrium-90 (a pure beta emitter) microspheres, which are injected into the hepatic arteries. This article reviews the safety and survival of patients with hepatocellular carcinoma who were treated with yttrium-90 microspheres. Eighty patients were selected from a database of 108 yttrium-90 microsphere-treated patients and were staged by using Child-Pugh, Okuda, and Cancer of the Liver Italian Program scoring systems. Patients were treated with local, regional, and whole-liver approaches. Survival from first treatment was analyzed with Kaplan-Meier and Cox regression methods. Adverse events and complications of treatment were coded by using the Southwest Oncology Group toxicity scoring system. Patients received liver doses ranging from 47 to 270 Gy. Thirty-two patients (40%) received more than 1 treatment. Survival correlated with pretreatment Cancer of the Liver Italian Program scores ( P = .002), as well as with the individual Cancer of the Liver Italian Program components, Child-Pugh class, alpha-fetoprotein levels, and percentage of tumor replacement. Patients classified as Okuda stage I (n = 54) and II (n = 26) had median survival durations and 1-year survival rates of 628 days and 63%, and 384 days and 51%, respectively ( P = .02). One patient died of liver failure judged as possibly related to treatment. Thus, in selected patients with hepatocellular carcinoma, yttrium-90 microsphere treatment is safe and well tolerated. On the basis of these results, a randomized controlled trial is warranted comparing yttrium-90 microsphere treatment with transarterial chemoembolization by using the Cancer of the Liver Italian Program system for prospective stratified randomization.

  20. Preparation and drug controlled release of porous octyl-dextran microspheres.

    Science.gov (United States)

    Hou, Xin; Liu, Yanfei

    2015-01-01

    In this work, porous octyl-dextran microspheres with excellent properties were prepared by two steps. Firstly, dextran microspheres were synthesized by reversed-phase suspension polymerization. Secondly, octyl-dextran microspheres were prepared by the reaction between dextran microspheres and ethylhexyl glycidyl ether and freezing-drying method. Porous structure of microspheres was formed through the interaction between octyl groups and organic solvents. The structure, morphology, dry density, porosity and equilibrium water content of porous octyl-dextran microspheres were systematically investigated. The octyl content affected the properties of microspheres. The results showed that the dry density of microspheres decreased from 2.35 to 1.21 g/ml, porosity increased from 80.68 to 95.05% with the octyl content increasing from 0.49 to 2.28 mmol/g. Meanwhile, the equilibrium water content presented a peak value (90.18%) when the octyl content was 2.25 mmol/g. Octyl-dextran microspheres showed high capacity. Naturally drug carriers play an important role in drug-delivery systems for their biodegradability, wide raw materials sources and nontoxicity. Doxorubicin (DOX) was used as a drug model to examine the drug-loading capacity of porous octyl-dextran microspheres. The drug-loading efficiency increased with the increase in microspheres/drug ratio, while the encapsulation efficiency decreased. When microspheres/drug mass ratio was 4/1, the drug-loading efficiency and encapsulation efficiency were 10.20 and 51.00%, respectively. The release rate of DOX increased as drug content and porosity increased. In conclusion, porous octyl-dextran microspheres were synthesized successfully and have the potential to serve as an effective delivery system in drug controlled release.

  1. FEMIC (Fibromes Embolises aux MICrospheres calibrees): Uterine Fibroid Embolization using Tris-acryl Microspheres. A French Multicenter Study

    International Nuclear Information System (INIS)

    Joffre, Francis; Tubiana, Jean-Michel; Pelage, Jean-Pierre

    2004-01-01

    Purpose: A French multicenter registry was set up to confirm the safety and efficacy of large calibrated tris-acryl gelatin microspheres for embolization of symptomatic fibroids. Methods: Technical recommendations included embolization using large microspheres (>500 μm) with no secondary embolization agent. Postprocedural pain, clinical improvement and adverse events were prospectively evaluated during a follow-up period of at least 6 months.Results: Eighty-five women complaining of fibroid-related symptoms entered the study. In seven women, a secondary embolization agent was used in addition to microspheres. Complete resolution of menorrhagia was achieved in 84% of women at 24 months and significant uterine and fibroid volume reductions were noted after 6 months (37% and 73%, respectively). Three women experienced definitive amenorrhea (4%) and two women required hysteroscopic resection of a fibroid. Eight women were treated by hysterectomy because of treatment failure. In seven of these women, treatment failure was explained by an additional cause of symptoms including diffuse adenomyosis, endometrial hyperplasia or ovarian artery supply to the fibroids.Conclusion: Limited uterine artery embolization using large microspheres has good clinical success rate with low postprocedural pain and complications. Women can expect excellent midterm results with a high level of symptom control and significant fibroid volume reduction. Confidence in the end-point recommended here may require the experience of several cases

  2. Photons in a spherical cavity

    International Nuclear Information System (INIS)

    Ionescu-Pallas, N.; Vlad, V.I.

    1999-01-01

    The spectrum of black body radiation at the absolute temperature T, in an ideal spherical cavity of radius R, is studied. The departures from the classical predictions of Planck's theory, due to the discrete energies of the radiation quanta confined inside the cavity, depend on the adiabatic invariant RT and are significant for RT≤ 1 cm K. Special attention was paid to evidence sudden changes in the spectrum intensities, forbidden bands of frequency, as well as major modifications of the total energy for RT≤ 1 cm K. Similar effects were present in case of a cubic cavity too. (authors)

  3. Robust platforms for creating organic-inorganic nanocomposite microspheres: decorating polymer microspheres containing mussel-inspired adhesion layers with inorganic nanoparticles.

    Science.gov (United States)

    Satoh, H; Saito, Y; Yabu, H

    2014-12-07

    We describe a method for creating robust and stable core-shell polymer microspheres decorated with inorganic (IO) nanoparticles (NPs) by a self-organization process and heterocoagulation using a mussel-inspired polymer adhesive layer between the IO NPs and the microspheres.

  4. Simulation Model of Microsphere Distribution for Selective Internal Radiation Therapy Agrees With Observations

    Energy Technology Data Exchange (ETDEWEB)

    Högberg, Jonas, E-mail: jonas.hogberg@radfys.gu.se [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Rizell, Magnus [Department of Surgery, Sahlgrenska University Hospital, Gothenburg (Sweden); Hultborn, Ragnar; Svensson, Johanna [Department of Oncology, Sahlgrenska University Hospital, Gothenburg (Sweden); Henrikson, Olof [Department of Radiology, Sahlgrenska University Hospital, Gothenburg (Sweden); Mölne, Johan [Department of Pathology, Sahlgrenska University Hospital, Gothenburg (Sweden); Gjertsson, Peter [Department of Clinical Physiology, Sahlgrenska University Hospital, Gothenburg (Sweden); Bernhardt, Peter [Department of Radiation Physics, Sahlgrenska Academy, University of Gothenburg, Gothenburg (Sweden); Department of Medical Physics and Biomedical Engineering, Sahlgrenska University Hospital, Gothenburg (Sweden)

    2016-10-01

    Purpose: To perform a detailed analysis of microsphere distribution in biopsy material from a patient treated with {sup 90}Y-labeled resin spheres and characterize microsphere distribution in the hepatic artery tree, and to construct a novel dichotomous bifurcation model for microsphere deposits and evaluate its accuracy in simulating the observed microsphere deposits. Methods and Materials: Our virtual model consisted of arteries that successively branched into 2 new generations of arteries at 20 nodes. The artery diameter exponentially decreased from the lowest generation to the highest generation. Three variable parameters were optimized to obtain concordance between simulations and measure microsphere distributions: an artery coefficient of variation (ACV) for the diameter of all artery generations and the microsphere flow distribution at the nodes; a hepatic tree distribution volume (HDV) for the artery tree; and an artery diameter reduction (ADR) parameter. The model was tested against previously measured activity concentrations in 84 biopsies from the liver of 1 patient. In 16 of 84 biopsies, the microsphere distribution regarding cluster size and localization in the artery tree was determined via light microscopy of 30-μm sections (mean concentration, 14 microspheres/mg; distributions divided into 3 groups with mean microsphere concentrations of 4.6, 14, and 28 microspheres/mg). Results: Single spheres and small clusters were observed in terminal arterioles, whereas large clusters, up to 450 microspheres, were observed in larger arterioles. For 14 microspheres/mg, the optimized parameter values were ACV=0.35, HDV = 50 cm{sup 3}, and ADR=6 μm. For 4.6 microspheres/mg, ACV and ADR decreased to 0.26 and 0 μm, respectively, whereas HDV increased to 130 cm{sup 3}. The opposite trend was observed for 28 microspheres/mg: ACV = 0.49, HDV = 20 cm{sup 3}, and ADR = 8 μm. Conclusion: Simulations and measurements reveal that microsphere clusters are

  5. Cavity and goaf control

    Energy Technology Data Exchange (ETDEWEB)

    Stassen, P

    1978-01-01

    A summary of stowing, including a definition, calculation of stowing material requirements and settling of packs is given. A) Stowing using dirt found locally - the dirt bands in the seam - the use of ripping dirt brought down by the scraper loader and used for packing purposes and the construction of dummy roads. B) Control of cavities by leaving short, thick props and timber chocks in place. C) Stowing methods involving imported firt: packing by hand, use of scraper loaders, slinger stowing and control led-gravity stowing. D) Pneumatic stowing: describes the various types of machine and their scope; pipelines, their installation and cost price; pneumatic stowing in conjunc tion with powered supports; the use of crusher-stowers for stowing ripping dirt; construction of anhydrite packs by means of a pneumatic stower. E) Hydraulic stowing: how it works, the materials involved, utilization conditions, the surface storage post, pipes, stoppings with stowed material, water removal, rates of hydraulic stowing, results of theoretical studies, and the use of hydraulic stowing in the metal-mines. F) Pumped packs: how they work, how the packs are installed, the strength of the packs and their various uses. G) Caving: describes the principle of caving, support patterns, caving with packs and makes a comparison between caving and stowing. H) Comparison between the various methods of stowing compares pneumatic with hydraulic stowing methods; compares packing by hand and mechanical stowing compares surface subsidence in terms of the method of goaf used underground. An appendix gives details of equipment used. (15 refs.) (In French)

  6. Loggerhead oral cavity morphometry study

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Standard external morphometrics and internal oral cavity morphometrics data were collected on wild and captive reared loggerhead sea turtles in size classes ranging...

  7. Niobium LEP 2 accelerating cavities

    CERN Multimedia

    An accelerating cavity from LEP. This could be cut open to show the layer of niobium on the inside. Operating at 4.2 degrees above absolute zero, the niobium is superconducting and carries an accelerating field of 6 million volts per metre with negligible losses. Each cavity has a surface of 6 m2. The niobium layer is only 1.2 microns thick, ten times thinner than a hair. Such a large area had never been coated to such a high accuracy. A speck of dust could ruin the performance of the whole cavity so the work had to be done in an extremely clean environment. These challenging requirements pushed European industry to new achievements. 256 of these cavities were used in an upgrade of the LEP accelerator to double the energy of the particle beams.

  8. Bistability of Cavity Magnon Polaritons

    Science.gov (United States)

    Wang, Yi-Pu; Zhang, Guo-Qiang; Zhang, Dengke; Li, Tie-Fu; Hu, C.-M.; You, J. Q.

    2018-01-01

    We report the first observation of the magnon-polariton bistability in a cavity magnonics system consisting of cavity photons strongly interacting with the magnons in a small yttrium iron garnet (YIG) sphere. The bistable behaviors emerged as sharp frequency switchings of the cavity magnon polaritons (CMPs) and related to the transition between states with large and small numbers of polaritons. In our experiment, we align, respectively, the [100] and [110] crystallographic axes of the YIG sphere parallel to the static magnetic field and find very different bistable behaviors (e.g., clockwise and counter-clockwise hysteresis loops) in these two cases. The experimental results are well fitted and explained as being due to the Kerr nonlinearity with either a positive or negative coefficient. Moreover, when the magnetic field is tuned away from the anticrossing point of CMPs, we observe simultaneous bistability of both magnons and cavity photons by applying a drive field on the lower branch.

  9. Design of rf conditioner cavities

    International Nuclear Information System (INIS)

    Govil, R.; Rimmer, R.A.; Sessler, A.; Kirk, H.G.

    1992-06-01

    Theoretical studies are made of radio frequency structures which can be used to condition electron beams so as to greatly reduce the stringent emittance requirements for successful lasing in a free-electron laser. The basic strategy of conditioning calls for modulating an electron beam in the transverse dimension, by a periodic focusing channel, while it traverses a series of rf cavities, each operating in a TM 210 mode. In this paper, we analyze the cavities both analytically and numerically (using MAFIA simulations). We find that when cylindrical symmetry is broken the coupling impedance can be greatly enhanced. We present results showing various performance characteristics as a function of cavity parameters, as well as possible designs for conditioning cavities

  10. SRF Cavity Fabrication and Materials

    CERN Document Server

    Singer, W

    2014-07-17

    The technological and metallurgical requirements of material for highgradient superconducting cavities are described. High-purity niobium, as the preferred metal for the fabrication of superconducting accelerating cavities, should meet exact specifications. The content of interstitial impurities such as oxygen, nitrogen, and carbon must be below 10μg/g. The hydrogen content should be kept below 2μg/g to prevent degradation of the Q-value under certain cool-down conditions. The material should be free of flaws (foreign material inclusions or cracks and laminations) that can initiate a thermal breakdown. Defects may be detected by quality control methods such as eddy current scanning and identified by a number of special methods. Conventional and alternative cavity fabrication methods are reviewed. Conventionally, niobium cavities are fabricated from sheet niobium by the formation of half-cells by deep drawing, followed by trim machining and Electron-Beam Welding (EBW). The welding of half-cells is a delicate...

  11. LEP Radio Frequency Copper Cavity

    CERN Multimedia

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  12. Investigation of control conditions of uranium dioxide pellets sinterability through microspheres

    International Nuclear Information System (INIS)

    Assis, Gino de.

    1996-01-01

    Promotion or inhibition of ceramic powders sinterability, the decisive question in ceramic processing is approached in this dissertation. Each high density microsphere has been considered as a solid inclusion in a low density microspheres matrix, generating big pores. Such pores make it difficult for the pellets density due the fact that they are difficult to be eliminated. A master mixture, allowing the pellet densification in the projected range has been reached. Batches of microspheres have been observed sometimes with high apparent density and sometimes with low apparent density. This apparent density variation was attributed to changing the oxygen partial pressure during calcination under air atmosphere. It is evident that the control of the apparent density of the microspheres needs a further research in order to adjust the sinterability of the microspheres on the desired level.It was demonstrated that the produced microspheres do not have impurities levels that can promote its sinterability or avoid their use in nuclear area

  13. Characterization of unsaturated fatty acid sustained-release microspheres for long-term algal inhibition.

    Science.gov (United States)

    Ni, Lixiao; Jie, Xiaoting; Wang, Peifang; Li, Shiyin; Hu, Shuzhen; Li, Yiping; Li, Yong; Acharya, Kumud

    2015-02-01

    The unsaturated fatty acid (linoleic acid) sustained-release microspheres were prepared with linoleic acid (LA) using alginate-chitosan microcapsule technology. These LA sustained-release microspheres had a high encapsulation efficiency (up to 62%) tested by high performance liquid chromatography with a photo diode array. The dry microspheres were characterized by a scanning electron microscope, X-ray diffraction measurement, dynamic thermogravimetric analysis and Fourier transform infrared spectral analysis. The results of characterization showed that the microspheres had good thermal stability (decomposition temperature of 236°C), stable and temperature independent release properties (release time of more than 40 d). Compared to direct dosing of LA, LA sustained-released microspheres could inhibit Microcystis aeruginosa growth to the non-growth state. The results of this study suggested that the LA sustained-release microspheres may be a potential candidate for algal inhibition. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Recent advances in polymeric microspheres for parenteral drug delivery--part 1.

    Science.gov (United States)

    Mao, Shirui; Guo, Chunqiang; Shi, Yi; Li, Luk Chiu

    2012-09-01

    Polymeric microspheres have been established as a valuable parenteral drug delivery system for sustained release of therapeutic agents via subcutaneous or intramuscular injection. Biodegradable polymers which are either synthetic or from natural sources are reviewed with respect to recent advances in exploring their applications for microsphere fabrications. New information on the impact of formulation variables on the properties of microspheres formed by an emulsion method was also presented. The characterization of microspheres using advanced physical analytical techniques was also reviewed and the utilization of the information in assessing in vivo performance of the product was also highlighted. The broad clinical use of microspheres for delivery of therapeutic agents in particular biologics such as proteins has not been realized commercially. The limited availability of biodegradable polymers with a long history of regulatory approval and the challenges in gaining regulatory approval of a new polymer have hindered the development of microspheres for parenteral drug delivery.

  15. TESLA superconducting RF cavity development

    International Nuclear Information System (INIS)

    Koepke, K.

    1995-01-01

    The TESLA collaboration has made steady progress since its first official meeting at Cornell in 1990. The infrastructure necessary to assemble and test superconducting rf cavities has been installed at the TESLA Test Facility (TTF) at DESY. 5-cell, 1.3 GHz cavities have been fabricated and have reached accelerating fields of 25 MV/m. Full sized 9-cell copper cavities of TESLA geometry have been measured to verify the higher order modes present and to evaluate HOM coupling designs. The design of the TESLA 9-cell cavity has been finalized and industry has started delivery. Two prototype 9-cell niobium cavities in their first tests have reached accelerating fields of 10 MV/m and 15 MV/m in a vertical dewar after high peak power (HPP) conditioning. The first 12 m TESLA cryomodule that will house 8 9-cell cavities is scheduled to be delivered in Spring 1995. A design report for the TTF is in progress. The TTF test linac is scheduled to be commissioned in 1996/1997. (orig.)

  16. A general approach to mesoporous metal oxide microspheres loaded with noble metal nanoparticles

    KAUST Repository

    Jin, Zhao; Xiao, Manda; Bao, Zhihong; Wang, Peng; Wang, Jianfang

    2012-01-01

    Catalytic microspheres: A general approach is demonstrated for the facile preparation of mesoporous metal oxide microspheres loaded with noble metal nanoparticles (see TEM image in the picture). Among 18 oxide/noble metal catalysts, TiO 2/0.1 mol Pd microspheres showed the highest turnover frequency in NaBH 4 reduction of 4-nitrophenol (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Microspheres of poly(ε-caprolactone) loaded Holmium-165: morphology and thermal degradation behavior

    International Nuclear Information System (INIS)

    Geraldes, Adriana Napoleao; Miyamoto, Douglas Massao; Lira, Raphael Arivar de; Osso Junior, Joao Alberto; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de

    2011-01-01

    Polycaprolactone (PCL), being one of the most important biocompatible and biodegradable aliphatic polyester, provides many potential biomedical. The preparation of biodegradable materials, polymer-based microspheres, is being developed by our group and the goal is to prepare and label with Ho-165 different polymer-based microspheres. The use of radionuclide-loaded microspheres is a promising treatment of liver malignancies. PCL microspheres can be loaded with holmium acetylacetonate (HoAcAc). PCL and PCL/HoAcAc microspheres were prepared by an emulsion solvent extraction/evaporation technique. The PCL/ HoAcAc microspheres were irradiated in a nuclear reactor IEA-R1 at IPEN/CNEN-SP to radionuclide activation. Gamma irradiation was performed at 25 and 50 kGy doses. The microspheres were evaluated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TG), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and con focal laser scanning microscopy (CLSM). In the CLSM images were observed emission in 488 nm characteristic of holmium. The SEM surface image of PCL/HoAcAc microspheres showed more roughness than PCL microspheres. TG of PCL/HoAcAc microspheres showed a substantial weight loss above 200 degree C, indicating decomposition of HoAcAc. The residual weight indicates the presence of Ho 2 O 3 . Gamma irradiation at 25 and 50 kGy doses had no effect on the PCL/HoAcAc microspheres, which indicates that the chemical composition of the microspheres had not change. (author)

  18. Microspheres of poly({epsilon}-caprolactone) loaded Holmium-165: morphology and thermal degradation behavior

    Energy Technology Data Exchange (ETDEWEB)

    Geraldes, Adriana Napoleao; Miyamoto, Douglas Massao; Lira, Raphael Arivar de; Osso Junior, Joao Alberto; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Polycaprolactone (PCL), being one of the most important biocompatible and biodegradable aliphatic polyester, provides many potential biomedical. The preparation of biodegradable materials, polymer-based microspheres, is being developed by our group and the goal is to prepare and label with Ho-165 different polymer-based microspheres. The use of radionuclide-loaded microspheres is a promising treatment of liver malignancies. PCL microspheres can be loaded with holmium acetylacetonate (HoAcAc). PCL and PCL/HoAcAc microspheres were prepared by an emulsion solvent extraction/evaporation technique. The PCL/ HoAcAc microspheres were irradiated in a nuclear reactor IEA-R1 at IPEN/CNEN-SP to radionuclide activation. Gamma irradiation was performed at 25 and 50 kGy doses. The microspheres were evaluated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TG), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and con focal laser scanning microscopy (CLSM). In the CLSM images were observed emission in 488 nm characteristic of holmium. The SEM surface image of PCL/HoAcAc microspheres showed more roughness than PCL microspheres. TG of PCL/HoAcAc microspheres showed a substantial weight loss above 200 degree C, indicating decomposition of HoAcAc. The residual weight indicates the presence of Ho{sub 2}O{sub 3}. Gamma irradiation at 25 and 50 kGy doses had no effect on the PCL/HoAcAc microspheres, which indicates that the chemical composition of the microspheres had not change. (author)

  19. A general approach to mesoporous metal oxide microspheres loaded with noble metal nanoparticles

    KAUST Repository

    Jin, Zhao

    2012-04-26

    Catalytic microspheres: A general approach is demonstrated for the facile preparation of mesoporous metal oxide microspheres loaded with noble metal nanoparticles (see TEM image in the picture). Among 18 oxide/noble metal catalysts, TiO 2/0.1 mol Pd microspheres showed the highest turnover frequency in NaBH 4 reduction of 4-nitrophenol (see picture). Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Preparation and characterization of composite microspheres for brachytherapy and hyperthermia treatment of cancer

    International Nuclear Information System (INIS)

    Zhao Di; Huang Wenhai; Rahaman, Mohamed N.; Day, Delbert E.; Wang Deping; Gu Yifei

    2012-01-01

    Composite microspheres were prepared by coating yttrium–aluminum–silicate (YAS) glass microspheres (20–30 μm) with a layer of Fe 3 O 4 nanoparticles and evaluated for potential use in brachytherapy and hyperthermia treatment of cancer. After neutron activation to form the β-emitting 90 Y radionuclide, the composite microspheres can be injected into a patient to destroy cancerous tumors; at the same time, the composite microspheres can generate heat upon application of a magnetic field to also destroy the tumors. The results showed that the composite microspheres were chemically durable when immersed in a simulated body fluid (SBF), with ∼ 0.25% weight loss and ∼ 3.2% yttrium dissolved into the SBF after 30 days at 37 °C. The composite microspheres also showed ferromagnetic properties as a result of the Fe 3 O 4 coating; when immersed in water at 20 °C (20 mg in 1 mL of water), the application of an alternating magnetic field produced a temperature increase from 20 °C to 38−46 °C depending on the thickness of the Fe 3 O 4 coating. The results indicate that these composite microspheres have promising potential in combined brachytherapy and hyperthermia treatment of cancerous tumors. - Highlights: ► Composite microspheres for brachytherapy and hyperthermia treatment of cancer. ► Fe 3 O 4 nanoparticles coated on the yttrium–aluminum–silicate glass microspheres. ► Microspheres are chemically stable in SBF. ► Microspheres can generate heat for hyperthermia under an alternating magnetic field. ► Microspheres can emit β-rays for brachytherapy after neutron activation.

  1. Encapsulation of azithromycin into polymeric microspheres by reduced pressure-solvent evaporation method

    DEFF Research Database (Denmark)

    Li, Xiujuan; Chang, Si; Du, Guangsheng

    2012-01-01

    Azithromycin loaded microspheres with blends of poly-l-lactide and ploy-D,L-lactide-co-glycolide as matrices were prepared by the atmosphere-solvent evaporation (ASE) and reduced pressure-solvent evaporation (RSE) method. Both the X-ray diffraction spectra and DSC thermographs demonstrated...... characteristics and release profiles of microspheres. In conclusion, the overall improvement of microspheres in appearance, encapsulation efficiency and controlled drug release through the RSE method could be easily fulfilled under optimal preparation conditions....

  2. PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP ON RHIC SPIN PHYSICS III AND IV, POLARIZED PARTONS AT HIGH Q2 REGION (VOLUME 31)

    International Nuclear Information System (INIS)

    BUNCE, G.; VIGDOR, S.

    2001-01-01

    International workshop on II Polarized Partons at High Q2 region 11 was held at the Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto, Japan on October 13-14, 2000, as a satellite of the international conference ''SPIN 2000'' (Osaka, Japan, October 16-21,2000). This workshop was supported by RIKEN (The Institute of Physical and Chemical Research) and by Yukawa Institute. The scientific program was focused on the upcoming polarized collider RHIC. The workshop was also an annual meeting of RHIC Spin Collaboration (RSC). The number of participants was 55, including 28 foreign visitors and 8 foreign-resident Japanese participants, reflecting the international nature of the RHIC spin program. At the workshop there were 25 oral presentations in four sessions, (1) RHIC Spin Commissioning, (2) Polarized Partons, Present and Future, (3) New Ideas on Polarization Phenomena, (4) Strategy for the Coming Spin Running. In (1) the successful polarized proton commissioning and the readiness of the accelerator for the physics program impressed us. In (2) and (3) active discussions were made on the new structure function to be firstly measured at RHIC, and several new theoretical ideas were presented. In session (4) we have established a plan for the beam time requirement toward the first collision of polarized protons. These proceedings include the transparencies presented at the workshop. The discussion on ''Strategy for the Coming Spin Running'' was summarized by the chairman of the session, S. Vigdor and G. Bunce

  3. Impact of nitrogen doping of niobium superconducting cavities on the sensitivity of surface resistance to trapped magnetic flux

    Science.gov (United States)

    Gonnella, Dan; Kaufman, John; Liepe, Matthias

    2016-02-01

    Future particle accelerators such as the SLAC "Linac Coherent Light Source-II" (LCLS-II) and the proposed Cornell Energy Recovery Linac require hundreds of superconducting radio-frequency (SRF) niobium cavities operating in continuous wave mode. In order to achieve economic feasibility of projects such as these, the cavities must achieve a very high intrinsic quality factor (Q0) to keep cryogenic losses within feasible limits. To reach these high Q0's in the case of LCLS-II, nitrogen-doping of niobium cavities has been selected as the cavity preparation technique. When dealing with Q0's greater than 1 × 1010, the effects of ambient magnetic field on Q0 become significant. Here, we show that the sensitivity to RF losses from trapped magnetic field in a cavity's walls is strongly dependent on the cavity preparation. Specifically, standard electropolished and 120 °C baked cavities show a sensitivity of residual resistance from trapped magnetic flux of ˜0.6 and ˜0.8 nΩ/mG trapped, respectively, while nitrogen-doped cavities show a higher sensitivity of residual resistance from trapped magnetic flux of ˜1 to 5 nΩ/mG trapped. We show that this difference in sensitivities is directly related to the mean free path of the RF surface layer of the niobium: shorter mean free paths lead to less sensitivity of residual resistance to trapped magnetic flux in the dirty limit (ℓ ≪ ξ0), while longer mean free paths lead to lower sensitivity of residual resistance to trapped magnetic flux in the clean limit (ℓ ≫ ξ0). These experimental results are also shown to have good agreement with recent theoretical predictions for pinned vortex lines oscillating in RF fields.

  4. Polydimethylsiloxane microspheres with poly(methyl methacrylate) coating: Modelling, preparation, and characterization

    DEFF Research Database (Denmark)

    Ma, Baoguang; Hansen, Jens Henrik; Hvilsted, Søren

    2015-01-01

    functional PDMS microspheres were coated with poly(methyl methacrylate) (PMMA) by spin coating with different concentrations of PMMA solutions. The quality of the resulting PMMA shell is investigated using rheological measurements at 50 8C with a timesweep procedure. The results strongly suggest that PMMA-coated...... PDMS microspheres react around 20 times slower than the uncoated ones, and that the PMMA shell significantly hinders the reaction between the PDMS microsphere and cross-linker. Thus the thin PMMA shells are very efficient in protecting the reactive PDMS microspheres, since the PMMA shell forms...

  5. Method for selecting hollow microspheres for use in laser fusion targets

    Science.gov (United States)

    Farnum, Eugene H.; Fries, R. Jay; Havenhill, Jerry W.; Smith, Maurice Lee; Stoltz, Daniel L.

    1976-01-01

    Hollow microspheres having thin and very uniform wall thickness are useful as containers for the deuterium and tritium gas mixture used as a fuel in laser fusion targets. Hollow microspheres are commercially available; however, in commercial lots only a very small number meet the rigid requirements for use in laser fusion targets. Those meeting these requirements may be separated from the unsuitable ones by subjecting the commercial lot to size and density separations and then by subjecting those hollow microspheres thus separated to an external pressurization at which those which are aspherical or which have nonuniform walls are broken and separating the sound hollow microspheres from the broken ones.

  6. Controllable growth and photocatalytic activity of Cu{sub 2}O solid microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Hong; Zhang, Junying, E-mail: zjy@buaa.edu.cn; Wang, Mei

    2013-09-01

    Graphical abstract: - Highlights: • 3 μm uniform Cu{sub 2}O solid microspheres with abundant nanopores are achieved. • NH{sub 2}OH·HCl and SDS are main factors that manipulate morphologies of Cu{sub 2}O particles. • Surface features of microspheres influenced the photocatalytic activity of Cu{sub 2}O. • Microspheres are transforming to polyhedrons with extended holding time. - Abstract: A series of Cu{sub 2}O solid microspheres with different surface features were prepared and their photocatalytic activities were studied. The experiment conditions were investigated and the formation mechanism was explored systematically. It was found that varying the amounts of NH{sub 2}OH·HCl reductant in alkaline solutions changed the reaction process and thus altered the surface features of Cu{sub 2}O microspheres. Sodium dodecyl sulfate (SDS) surfactant, introduced as a morphology directing agent, caused the nuclei aggregation and growth process of Cu{sub 2}O solid microspheres by precisely realizing the opposite charges’ directional attraction. This SDS-mediated method can be readily extended to synthesizing solid microspheres of other metal oxides. Meanwhile, it was found that Cu{sub 2}O solid microspheres with abundant nanopores on the surface showed much higher efficient catalytic activity for decoloring methyl orange (MO) aqueous solution than with other surface features under visible light irradiation. Furthermore, we found that prolonging the holding time made Cu{sub 2}O microspheres transform to polyhedrons.

  7. Study on Magnetic Responsibility of Rare Earth Ferrite/Polyacrylamide Magnetic Microsphere

    Institute of Scientific and Technical Information of China (English)

    Zhang Ming; Wang Zhifeng; Zhang Hong; Dai Shaojun; Qiu Guanming; Okamoto Hiroshi

    2005-01-01

    In inverse microemulsion, rare earth ferrite/polyacrylamide magnetic microsphere were prepared and their magnetic responsibility were studied by magnetic balance. Results indicate that the magnetic responsibility of microsphere relates to magnetic moment of rare earth ion, and it can be improved by the addition of dysprosium ion of high magnetic moment. Dysprosium content has an effect on magnetic responsibility of dysprosium ferrite/polyacrylamide magnetic microsphere. The microsphere displays strong magnetic responsibility when the molar ratio of Dy3+/iron is 0.20.

  8. Preparation of chitosan/nano hydroxyapatite organic-inorganic hybrid microspheres for bone repair.

    Science.gov (United States)

    Chen, Jingdi; Pan, Panpan; Zhang, Yujue; Zhong, Shengnan; Zhang, Qiqing

    2015-10-01

    In this work, we encapsulated icariin (ICA) into chitosan (CS)/nano hydroxyapatite (nHAP) composite microspheres to form organic-inorganic hybrid microspheres for drug delivery carrier. The composition and morphology of composite microspheres were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and differential scanning calorimetry- thermogravimetric analysis (DSC-TGA). Moreover, we further studied the performance of swelling properties, degradation properties and drug release behavior of the microspheres. ICA, the extract of traditional Chinese medicine-epimedium, was combined to study drug release properties of the microspheres. ICA loaded microspheres take on a sustained release behavior, which can be not only ascribed to electrostatic interaction between reactive negative hydroxyl (OH) of ICA and positive amine groups (NH₂) of CS, but also depended on the homogeneous dispersion of HAP nanoparticles inside CS organic matrix. In addition, the adhesion and morphology of osteoblasts were detected by inverted fluorescence microscopy. The biocompatibility of CS/nHAP/ICA microspheres was evaluated by the MTT cytotoxicity assay, Hoechst 33258 and PI fluorescence staining. These studies demonstrate that composite microspheres provide a suitable microenvironment for osteoblast attachment and proliferation. It can be speculated that the ICA loaded CS-based organic-inorganic hybrid microspheres might have potential applications in drug delivery systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. INVESTIGATION OF DRUG RELEASE FROM BIODEGRADABLE PLG MICROSPHERES: EXPERIMENT AND THEORY

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS, MALCOLM J. [Los Alamos National Laboratory; BERCHANE, NADER S. [Los Alamos National Laboratory; CARSON, KENNETH H. [Los Alamos National Laboratory; RICE-FICHT, ALLISON C. [Los Alamos National Laboratory

    2007-01-30

    Piroxicam containing PLG microspheres having different size distributions were fabricated, and in vitro release kinetics were determined for each preparation. Based on the experimental results, a suitable mathematical theory has been developed that incorporates the effect of microsphere size distribution and polymer degradation on drug release. We show from in vitro release experiments that microsphere size has a significant effect on drug release rate. The initial release rate decreased with an increase in microsphere size. In addition, the release profile changed from first order to concave-upward (sigmoidal) as the system size was increased. The mathematical model gave a good fit to the experimental release data.

  10. Recent advances in Pt coating of microspheres by a batch magnetron sputtering process

    International Nuclear Information System (INIS)

    Hsieh, E.J.; Meyer, S.F.

    1980-01-01

    Some proposed inertial confinement fusion targets require high-Z, high density metal coatings on glass microspheres. Platinum, which satisfies the high-Z and density requirements, can be coated onto microspheres with a batch magnetron sputtering process incorporating oxygen as a dopant gas to prevent the microspheres from sticking. This paper outlines recent progress in three areas: First, the coating process has been improved; second, the oxygen content and resistivity of the oxygen doped platinum films are analyzed; and third, the roles oxygen may play in reducing microsphere sticking during sputtering are discussed in regard to cold welding, Van der Waals bonding, electrostatic sticking, and sintering

  11. Effect of various polymers concentrations on physicochemical properties of floating microspheres.

    Science.gov (United States)

    Jagtap, Y M; Bhujbal, R K; Ranade, A N; Ranpise, N S

    2012-11-01

    Floating microspheres have emerged as a potential candidate for gastroretentive drug delivery system. For developing a desired intragastric floatation system employing these microspheres, it is necessary to select an appropriate balance between buoyancy and drug releasing rate. These properties mainly depend on the polymers used in the formulation of the microspheres. Hence it is necessory to study the effect of these polymer concentrations on the various physicochemical properties of the microspheres. Floating microspheres were prepared by emulsion solvent evaporation technique utilising different polymers such as ethyl cellulose, Eudragit(®) RS and Eudragit(®) RL by dissolving them in a mixture of dichloromethane and methanol. Release modifiers studied were hydroxypropyl methylcellulose K4M, hydroxypropyl methylcellulose E50 LV and Eudragit(®) EPO. Prepared microspheres were analysed for particle size, surface morphology, entrapment efficiency, buoyancy, differential scanning calorimetry and in-vitro drug release. Ethyl cellulose and Eudragit(®) EPO resulted microspheres with high percentage yield, excellent spherical shape but had very less buoyancies with a high cumulative drug release. Ethyl cellulose microspheres prepared using hydroxypropyl methylcellulose K4M showed more sustained drug release and high buoyancies than that of the microspheres formulated with the hydroxypropyl methylcellulose E50 LV. Amongst these hydroxypropyl methylcellulose E50 LV showed good balance between buoyancy and the drug release.

  12. Synthesis and characterization of magnesium gluconate contained poly(lactic-co-glycolic acid)/chitosan microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, Shekh M. [Department of Chemical, Biological and Bioengineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Mahoney, Christopher [Department of Bioengineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, PA 15250 (United States); Sankar, Jagannathan [NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Department of Mechanical Engineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); Marra, Kacey G. [NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States); Department of Bioengineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, PA 15250 (United States); Department of Plastic Surgery, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA 15250 (United States); McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive, Pittsburgh, PA 15250 (United States); Bhattarai, Narayan, E-mail: nbhattar@ncat.edu [Department of Chemical, Biological and Bioengineering, North Carolina A& T State University, 1601 East Market Street, Greensboro, NC 27411 (United States); NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, North Carolina A& T State University, Greensboro, NC 27411 (United States)

    2016-01-15

    Graphical abstract: - Highlights: • Magnesium gluconate contained PLGA/chitosan microspheres were fabricated. • In vitro release of magnesium ions was performed using Xylidyl Blue assay. • Chitosan coated PLGA can significantly control the release of magnesium ions. • Cellular compatibility was tested using adipose-derived stem cells and PC12 cells. • The cells encounter acceptably low levels of damage in contact with microspheres. - Abstract: The goal of this study was to fabricate and investigate the chitosan coated poly(lactic-co-glycolic acid) (PLGA) microspheres for the development of controlled release magnesium delivery system. PLGA based microspheres are ideal vehicles for many controlled release drug delivery applications. Chitosan is a naturally occurring biodegradable and biocompatible polysaccharide, which can coat the surface of PLGA to alter the release of drugs. Magnesium gluconate (MgG) was encapsulated in the PLGA and PLGA/chitosan microspheres by utilizing the double emulsion solvent evaporation technique for controlled release study. The microspheres were tested with respect to several physicochemical and biological properties, including morphology, chemical structure, chitosan adsorption efficiency, magnesium encapsulation efficiency, in vitro release of magnesium ions, and cellular compatibility using both human adipose-derived stem cells (ASCs) and PC12 cells. Chitosan coated PLGA microspheres can significantly control the release of magnesium ions compared to uncoated PLGA microspheres. Both coated and uncoated microspheres showed good cellular compatibility.

  13. Methanol and ethanol electrooxidation on Pt and Pd supported on carbon microspheres in alkaline media

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Changwei; Cheng, Liqiang; Liu, Yingliang [Department of Chemistry and Institute of Nanochemistry, Jinan University, Guangzhou 510632 (China); Shen, Peikang [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China)

    2007-05-15

    Noble metal (Pt, Pd) electrocatalysts supported on carbon microspheres (CMS) are used for methanol and ethanol oxidation in alkaline media. The results show that noble metal electrocatalysts supported on carbon microspheres give better performance than that supported on carbon black. It is well known that palladium is not a good electrocatalyst for methanol oxidation, but it shows excellently higher activity and better steady-state electrolysis than Pt for ethanol electrooxidation in alkaline media. The results show a synergistic effect by the interaction between Pd and carbon microspheres. The Pd supported on carbon microspheres in this paper possesses excellent electrocatalytic properties and may be of great potential in direct ethanol fuel cells. (author)

  14. 21 CFR 872.3260 - Cavity varnish.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cavity varnish. 872.3260 Section 872.3260 Food and... DENTAL DEVICES Prosthetic Devices § 872.3260 Cavity varnish. (a) Identification. Cavity varnish is a device that consists of a compound intended to coat a prepared cavity of a tooth before insertion of...

  15. Investigation of the influence of the proximity effect and randomness on a photolithographically fabricated photonic crystal nanobeam cavity

    Science.gov (United States)

    Tetsumoto, Tomohiro; Kumazaki, Hajime; Ishida, Rammaru; Tanabe, Takasumi

    2018-01-01

    Recent progress on the fabrication techniques used in silicon photonics foundries has enabled us to fabricate photonic crystal (PhC) nanocavities using a complementary metal-oxide-semiconductor (CMOS) compatible process. A high Q two-dimensional PhC nanocavity and a one-dimensional nanobeam PhC cavity with a Q exceeding 100 thousand have been fabricated using ArF excimer laser immersion lithography. These are important steps toward the fusion of silicon photonics devices and PhC devices. Although the fabrication must be reproducible for industrial applications, the properties of PhC nanocavities are sensitively affected by the proximity effect and randomness. In this study, we quantitatively investigated the influence of the proximity effect and randomness on a silicon nanobeam PhC cavity. First, we discussed the optical properties of cavities defined with one- and two-step exposure methods, which revealed the necessity of a multi-stage exposure process for our structure. Then, we investigated the impact of block structures placed next to the cavities. The presence of the blocks modified the resonant wavelength of the cavities by about 10 nm. The highest Q we obtained was over 100 thousand. We also discussed the influence of photomask misalignment, which is also a possible cause of disorders in the photolithographic fabrication process. This study will provide useful information for fabricating integrated photonic circuits with PhC nanocavities using a photolithographic process.

  16. The fundamental science of nitrogen-doping of niobium superconducting cavities

    Science.gov (United States)

    Gonnella, Daniel Alfred

    theoretical predictions. The nature of the low-field quench in nitrogen-doped cavities was also studied with high power pulsed measurements and found to be related to a lowering of the lower critical field, Bc1 due to lowering of the mean free path. Finally, five cryomodule tests were carried out on nitrogen-doped 9-cell cavities to understand how the cryomodule environment affects the performance of doped cavities. This is the first demonstration that environmental factors can be controlled to achieve high Q0 of more than 2.7x10 10 at 16 MV/m and 2.0 K in a cryomodule, meeting and exceeding the specification for LCLS-II. The work presented here represents a significant leap forward in the understanding of the underlying science behind nitrogen-doped cavities and demonstrates their readiness for use in future particle accelerators.

  17. TEM observations of crack tip: cavity interactions

    International Nuclear Information System (INIS)

    Horton, J.A.; Ohr, S.M.; Jesser, W.A.

    1981-01-01

    Crack tip-cavity interactions have been studied by performing room temperature deformation experiments in a transmission electron microscope on ion-irradiated type 316 stainless steel with small helium containing cavities. Slip dislocations emitted from a crack tip cut, sheared, and thereby elongated cavities without a volume enlargement. As the crack tip approached, a cavity volume enlargement occurred. Instead of the cavities continuing to enlarge until they touch, the walls between the cavities fractured. Fracture surface dimples do not correlate in size or density with these enlarged cavities

  18. Fabrication of elliptical SRF cavities

    Science.gov (United States)

    Singer, W.

    2017-03-01

    The technological and metallurgical requirements of material for high-gradient superconducting cavities are described. High-purity niobium, as the preferred metal for the fabrication of superconducting accelerating cavities, should meet exact specifications. The content of interstitial impurities such as oxygen, nitrogen, and carbon must be below 10 μg g-1. The hydrogen content should be kept below 2 μg g-1 to prevent degradation of the quality factor (Q-value) under certain cool-down conditions. The material should be free of flaws (foreign material inclusions or cracks and laminations) that can initiate a thermal breakdown. Traditional and alternative cavity mechanical fabrication methods are reviewed. Conventionally, niobium cavities are fabricated from sheet niobium by the formation of half-cells by deep drawing, followed by trim machining and electron beam welding. The welding of half-cells is a delicate procedure, requiring intermediate cleaning steps and a careful choice of weld parameters to achieve full penetration of the joints. A challenge for a welded construction is the tight mechanical and electrical tolerances. These can be maintained by a combination of mechanical and radio-frequency measurements on half-cells and by careful tracking of weld shrinkage. The main aspects of quality assurance and quality management are mentioned. The experiences of 800 cavities produced for the European XFEL are presented. Another cavity fabrication approach is slicing discs from the ingot and producing cavities by deep drawing and electron beam welding. Accelerating gradients at the level of 35-45 MV m-1 can be achieved by applying electrochemical polishing treatment. The single-crystal option (grain boundary free) is discussed. It seems that in this case, high performance can be achieved by a simplified treatment procedure. Fabrication of the elliptical resonators from a seamless pipe as an alternative is briefly described. This technology has yielded good

  19. Hydroforming of superconducting TESLA cavities

    International Nuclear Information System (INIS)

    Singer, W.; Kaiser, H.; Singer, X.

    2003-01-01

    Seamless fabrication of single-cell and multi-cell TESLA shape cavities by hydroforming has been developed at DESY. The forming takes place by expanding the seamless tube with internal water pressure while simultaneously swaging it axially. Tube radius and axial displacement are being computer controlled in accordance with results of FEM simulations and the experimentally obtained strain-stress curve of tube material. Several Nb single cell cavities have been produced. A first bulk Nb double cell cavity has been fabricated. The Nb seamless tubes have been produced by spinning and deep drawing. Surface treatment such as buffered chemical polishing, (BCP), electropolishing (EP), high pressure ultra pure water rinsing (HPR), annealing at 800degC and baking at ca. 150degC have been applied. The best single cell bulk Nb cavity has reached an accelerating gradient of Eacc > 42 MV/m after ca. 250 μm BCP and 100 μm EP. Several bimetallic NbCu single cell cavities of TESLA shape have been fabricated. The seamless tubes have been produced by explosive bonding and subsequent flow forming. The thicknesses of Nb and Cu layers in the tube wall are about 1 mm and 3 mm respectively. The RF performance of NbCu clad cavities is similar to that of bulk Nb cavities. The highest accelerating gradient achieved was 40 MV/m after ca. 180 μm BCP, annealing at 800degC and baking at 140degC for 30 hours. The degradation of the quality factor Qo after repeated quenching is moderate, after ca. 150 quenches it reaches the saturation point of Qo=1.4x10 10 at low field. This indicates that on the basis of RF performance and material costs the combination of hydroforming with tube cladding is a very promising option. (author)

  20. Partial Cavity Flows at High Reynolds Numbers

    Science.gov (United States)

    Makiharju, Simo; Elbing, Brian; Wiggins, Andrew; Dowling, David; Perlin, Marc; Ceccio, Steven

    2009-11-01

    Partial cavity flows created for friction drag reduction were examined on a large-scale. Partial cavities were investigated at Reynolds numbers up to 120 million, and stable cavities with frictional drag reduction of more than 95% were attained at optimal conditions. The model used was a 3 m wide and 12 m long flat plate with a plenum on the bottom. To create the partial cavity, air was injected at the base of an 18 cm backwards-facing step 2.1 m from the leading edge. The geometry at the cavity closure was varied for different flow speeds to optimize the closure of the cavity. Cavity gas flux, thickness, frictional loads, and cavity pressures were measured over a range of flow speeds and air injection fluxes. High-speed video was used extensively to investigate the unsteady three dimensional cavity closure, the overall cavity shape and oscillations.

  1. Study of neutron absorbing microspheres in research reactors - Neutronic analyse

    International Nuclear Information System (INIS)

    Gana Watkins, Ignacio A.; Prado, Miguel O.; Mazufri, Claudio; Tunon, Juan M

    2012-01-01

    Now-a-days, it is increasingly common for nuclear power plants, as well as research reactors, to be designed and built with an alternative safety system aside from control rods. The acids and/or salts in solution injection systems is most frequently used. However, these systems present several implementation and operation problems due to the physical and chemical properties of the used compounds. After analyzing these drawbacks, we developed a new alternative safety system that contains the absorbing element isolated from the aqueous medium. In this context, it's proposed the use of aluminum borosilicate microspheres. The current paper presents erosion wear experiments to determine under which conditions microspheres can be considered as a potential component of a secondary shut down system in a nuclear facility (author)

  2. Carbon microspheres as ball bearings in aqueous-based lubrication.

    Science.gov (United States)

    St Dennis, J E; Jin, Kejia; John, Vijay T; Pesika, Noshir S

    2011-07-01

    We present an exploratory study on a suspension of uniform carbon microspheres as a new class of aqueous-based lubricants. The surfactant-functionalized carbon microspheres (∼0.1 wt %) employ a rolling mechanism similar to ball bearings to provide low friction coefficients (μ ≈ 0.03) and minimize surface wear in shear experiments between various surfaces, even at high loads and high contact pressures. The size range, high monodispersity, and large yield stress of the C(μsphere), as well as the minimal environmental impact, are all desirable characteristics for the use of a C(μsphere)-SDS suspension as an alternative to oil-based lubricants in compatible devices and machinery.

  3. Polyacrylate microspheres composite for all-solid-state reference electrodes.

    Science.gov (United States)

    Kisiel, Anna; Donten, Mikołaj; Mieczkowski, Józef; Rius-Ruiz, F Xavier; Maksymiuk, Krzysztof; Michalska, Agata

    2010-09-01

    A novel concept is proposed for the encapsulation of components within polyacrylate microspheres, prior to their incorporation into a membrane phase. Thus finer and better controlled dispersion of heterogeneous membrane components can be achieved. This concept was verified by using a poly(n-butyl acrylate) membrane-based reference electrode as an example. In this example the proper dispersion of solid constituents of the heterogeneous membrane and prevention of their leakage are both of primary importance. Potassium chloride-loaded poly(n-butyl acrylate) microspheres were prepared and then left in contact with silver nitrate to convert some of the KCl into AgCl. The material obtained was introduced into a poly(n-butyl acrylate) membrane. The reference electrode membranes obtained in this way were characterized with much more stable potential (both in different electrolytes and over time) compared with electrodes prepared by the direct introduction of KCl and AgCl to the membrane.

  4. Coherent inflation for large quantum superpositions of levitated microspheres

    Science.gov (United States)

    Romero-Isart, Oriol

    2017-12-01

    We show that coherent inflation (CI), namely quantum dynamics generated by inverted conservative potentials acting on the center of mass of a massive object, is an enabling tool to prepare large spatial quantum superpositions in a double-slit experiment. Combined with cryogenic, extreme high vacuum, and low-vibration environments, we argue that it is experimentally feasible to exploit CI to prepare the center of mass of a micrometer-sized object in a spatial quantum superposition comparable to its size. In such a hitherto unexplored parameter regime gravitationally-induced decoherence could be unambiguously falsified. We present a protocol to implement CI in a double-slit experiment by letting a levitated microsphere traverse a static potential landscape. Such a protocol could be experimentally implemented with an all-magnetic scheme using superconducting microspheres.

  5. Synthesis and characterization of porous microspheres bearing pyrrolidone units

    Energy Technology Data Exchange (ETDEWEB)

    Maciejewska, M., E-mail: mmacieje@umcs.pl; Kołodyńska, D.

    2015-01-15

    Porous microspheres of glycydyl methacrylate (GMA) cross-linked with trimethylolpropane trimethacrylate (TRIM) were prepared with toluene as porogen by suspension-emulsion polymerization. With increasing molar ratio of the functional monomer to cross-linker, the epoxy group content increases significantly whereas the parameters of porous structure (specific surface area and total pore volume) decreases. In order to obtain adsorbents bearing functional groups the porous methacrylate network was modified by subsequent reaction with pyrrolidone. The materials were studied using elemental analysis, infrared spectroscopy, atomic force microscopy (AFM), attenuated total reflection (ATR) spectroscopy, Raman spectroscopy, thermal gravimetry. Additionally, polymers sorption capacity towards Cu(II) was investigated. - Highlights: • Porous microspheres with reactive epoxy group were synthesized. • Highly developed porous structure was created. • Pyrrolidone units were incorporated during ring–opening reaction. • Polymers sorption capacity towards Cu (II) was investigated.

  6. Chitosan magnetic microspheres for technological applications: Preparation and characterization

    International Nuclear Information System (INIS)

    Podzus, P.E.; Daraio, M.E.; Jacobo, S.E.

    2009-01-01

    One of the major applications of chitosan and its many derivatives are based on its ability to bind strongly heavy and toxic metal ions. In this study chitosan magnetic microspheres have been synthesized. Acetic acid (1%w/v) solution was used as solvent for the chitosan polymer solution (2%w/v) where magnetite nanoparticles were suspended in order to obtain a stable ferrofluid. Glutaraldehyde was used as cross-linker. The magnetic characteristic of these materials allows an easy removal after use if is necessary. The morphological characterization of the microspheres shows that they can be produced in the size range 800-1100 μm. The adsorption of Cu(II) onto chitosan-magnetite nanoparticles was studied in batch system. A second-order kinetic model was used to fit the kinetic data, leading to an equilibrium adsorption capacity of 19 mg Cu/g chitosan.

  7. PREPARATION AND CHARACTERIZATION OF POROUS WALLED HOLLOW GLASS MICROSPHERES

    Energy Technology Data Exchange (ETDEWEB)

    Raszewski, F; Erich Hansen, E; Ray Schumacher, R; David Peeler, D

    2008-04-21

    Porous-walled hollow glass microspheres (PWHGMs) of a modified alkali borosilicate composition have been successfully fabricated by combining the technology of producing hollow glass microspheres (HGMs) with the knowledge associated with porous glasses. HGMs are first formed by a powder glass--flame process, which are then transformed to PWHGMs by heat treatment and subsequent treatment in acid. Pore diameter and pore volume are most influenced by heat treatment temperature. Pore diameter is increased by a factor of 10 when samples are heat treated prior to acid leaching; 100 {angstrom} in non-heat treated samples to 1000 {angstrom} in samples heat treated at 600 C for 8 hours. As heat treatment time is increased from 8 hours to 24 hours there is a slight shift increase in pore diameter and little or no change in pore volume.

  8. Onion-like microspheres with tricomponent from gelable triblock copolymers.

    Science.gov (United States)

    Zhang, Ke; Gao, Lei; Chen, Yongming; Yang, Zhenzhong

    2010-06-01

    Onion-like functional microspheres with three alternate layers were obtained by aerosol-assisted self-assembly of a functional block copolymer, poly(3-(triethoxysilyl)propyl methacrylate)-block-polystyrene-block-poly(2-vinylpyridine) (PTEPM-b-PS-b-P2VP). Through self-gelation reaction occurred in the PTEPM layers, organic/inorganic hybrid functional spheres with highly ordered concentric curved lamellar structure were prepared. Using these hybrid onion-like microspheres as templates, gold ions were entrapped into the P2VP layers and then gold nanoparticles located in each P2VP layers were formed by a reduction. By dispersing in acidic water, the onion-like polymeric spheres were broken and, as a result, sandwich-like nanoplates with curved morphology were obtained. Copyright © 2010 Elsevier Inc. All rights reserved.

  9. Treatment of metastasis localizations by intratumoral injection of radionuclide microsphere

    International Nuclear Information System (INIS)

    Tuo Peiyu; Pang Yan; Zhu Dianqing; Chang Keli; Zhu Yanjia

    2001-01-01

    Objective: To evaluate the therapeutic effects of radionuclide-labeled microsphere by intratumoral injection into 18 patients with superficial metastasis tumor for treatment. Methods: 18 patients with superficial metastasis were treated with radionuclide-labeled microsphere ( 90 Y-GTMS and 32 P-GTMS) by multi-point intratumoral injection. Each injection dose was 11.1-18.5 MBq/g (tumor). Results: 1 patient was relieved completely, 9 were relieved partly, 5 were improved and 3 kept stable. The total rate of relief and virtual value were 55.6% and 83.3% respectively. Conclusion: Topical treatment by using radionuclide may help diminish the tumor, control its progress and ease the symptoms. Thus it can be used as a supplement of routine treatment of tumors and it should do some work in therapy of malignant tumors in late stages

  10. Normal Conducting RF Cavity for MICE

    International Nuclear Information System (INIS)

    Li, D.; DeMello, A.; Virostek, S.; Zisman, M.; Summers, D.

    2010-01-01

    Normal conducting RF cavities must be used for the cooling section of the international Muon Ionization Cooling Experiment (MICE), currently under construction at Rutherford Appleton Laboratory (RAL) in the UK. Eight 201-MHz cavities are needed for the MICE cooling section; fabrication of the first five cavities is complete. We report the cavity fabrication status including cavity design, fabrication techniques and preliminary low power RF measurements.

  11. Microsphere imaging with confocal microscopy and two photon microscopy

    International Nuclear Information System (INIS)

    Chun, Hyung Su; An, Kyung Won; Lee, Jai Hyung

    2002-01-01

    We have acquired images of polystyrene and fused-silica microsphere by using conventional optical microscopy, confocal microscopy and two-photon microscopy, and performed comparative analysis of these images. Different from conventional optical microscopy, confocal and two-photon microscopy had good optical sectioning capability. In addition, confocal microscopy and two-photon microscopy had better lateral resolution than conventional optical microscopy. These results are attributed to confocality and nonlinearity of confocal microscopy and two photon microscopy, respectively.

  12. Resin 90Y microsphere activity measurements for liver brachytherapy

    International Nuclear Information System (INIS)

    Dezarn, William A.; Kennedy, Andrew S.

    2007-01-01

    The measurement of the radioactivity administered to the patient is one of the major components of 90 Y microsphere liver brachytherapy. The activity of 90 Y microspheres in a glass delivery vial was measured in a dose calibrator. The calibration value to use for 90 Y in the dose calibrator was verified using an activity calibration standard provided by the microsphere manufacturer. This method allowed for the determination of a consistent, reproducible local activity standard. Additional measurements were made to determine some of the factors that could affect activity measurement. The axial response of the dose calibrator was determined by the ratio of activity measurements at the bottom and center of the dose calibrator. The axial response was 0.964 for a glass shipping vial, 1.001 for a glass V-vial, and 0.988 for a polycarbonate V-vial. Comparisons between activity measurements in the dose calibrator and those using a radiation survey meter were found to agree within 10%. It was determined that the dose calibrator method was superior to the survey meter method because the former allowed better defined measurement geometry and traceability of the activity standard back to the manufacturer. Part of the preparation of resin 90 Y microspheres for patient delivery is to draw out a predetermined activity from a shipping vial and place it into a V-vial for delivery to the patient. If the drawn activity was placed in a glass V-vial, the activity measured in the dose calibrator with a glass V-vial was 4% higher than the drawn activity from the shipping vial standard. If the drawn activity was placed in a polycarbonate V-vial, the activity measured in the dose calibrator with a polycarbonate V-vial activity was 20% higher than the drawn activity from the shipping vial standard. Careful characterization of the local activity measurement standard is recommended instead of simply accepting the calibration value of the dose calibrator manufacturer

  13. The measurement of radioactive microspheres in biological samples

    International Nuclear Information System (INIS)

    Mernagh, J.R.; Spiers, E.W.; Adiseshiah, M.

    1976-01-01

    Measurements of the distribution of radioactive microspheres are used in investigations of regional coronary blood flow, but the size and shape of the heart varies for different test animals, and the organ is frequently divided into smaller pieces for studies of regional perfusion. Errors are introduced by variations in the distribution of the radioactive source and the amount of Compton scatter in different samples. A technique has therefore been developed to allow the counting of these tissue samples in their original form, and correction factors have been derived to inter-relate the various counting geometries thus encountered. Dogs were injected with microspheres labelled with 141 Ce, 51 Cr or 85 Sr. The tissue samples did not require remodelling to fit a standard container, and allowance was made for the inhomogeneous distribution in the blood samples. The activities in the centrifuged blood samples were correlated with those from the tissue samples by a calibration procedure involving comparisons of the counts from samples of microspheres embedded in sachets of gelatine, and similar samples mixed with blood and then centrifuged. The calibration data have indicated that 51 Cr behaves anomalously, and its use as a label for microspheres may introduce unwarranted errors. A plane cylindrical 10 x 20 cm NaI detector was used, and a 'worst case' correction of 20% was found to be necessary for geometry effects. The accuracy of this method of correlating different geometries was tested by remodelling the same tissue sample into different sizes and comparing the results, and the validity of the technique was supported by agreement of the final results with previously published data. (U.K.)

  14. Immunomagnetic sulfonated hypercrosslinked polystyrene microspheres for electrochemical detection of proteins

    Czech Academy of Sciences Publication Activity Database

    Šálek, Petr; Korecká, L.; Horák, Daniel; Petrovský, Eduard; Kovářová, Jana; Metelka, R.; Čadková, M.; Bílková, Z.

    2011-01-01

    Roč. 21, č. 38 (2011), s. 14783-14792 ISSN 0959-9428 R&D Projects: GA ČR GA203/09/0857; GA ČR GA203/09/1242 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z30120515 Keywords : styrene * divinylbenzene * microspheres Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.968, year: 2011

  15. Carefully calibrated microsphere embolization of tumors and AVMs

    International Nuclear Information System (INIS)

    Laurent, A.; Wassef, M.; Beaujeux, R.; Hodes, J.E.; Gobin, P.Y.; Schenker, C.; Bouchez, B.; Brette, M.D.; Aymard, A.; Cophignon, J.; Merland, J.J.

    1990-01-01

    This paper evaluates the efficacy of a new type of uniformly calibrated microsphere for embolization of various pathologies. Fourteen tumors (five intracranial, eight extracranial, one spine), and seven facial arteriovenous malformations (AVMs) (nose, lip, and scalp) were embolized preoperatively. Angiographic, surgical devascularization, and histologic findings were correlated with the spheres' size. In the second part of the study, spinal cord (n = 22) and intracerbral (n = 14) AVM, Weber-Osler-Rendu disease (n = 2), and epistaxis (n = 1) embolization was angiographically evaluated

  16. Magnetic poly(glycidyl methacrylate) microspheres for protein capture

    Czech Academy of Sciences Publication Activity Database

    Koubková, Jana; Müller, P.; Hlídková, Helena; Plichta, Zdeněk; Proks, Vladimír; Vojtěšek, B.; Horák, Daniel

    2014-01-01

    Roč. 31, č. 5 (2014), s. 482-491 ISSN 1871-6784 R&D Projects: GA ČR GCP207/12/J013; GA MŠk 7E12053 EU Projects: European Commission(XE) 246513 - NADINE Institutional support: RVO:61389013 Keywords : glycidyl methacrylate * microspheres * protein p53 Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.898, year: 2014

  17. Porous spherical shells and microspheres by electrodispersion precipitation

    International Nuclear Information System (INIS)

    Harris, M.T.; Sisson, W.G.; Basaran, O.A.; Hayes, S.M.; Bobrowski, S.J.

    1994-01-01

    The ability to reproduce the synthesis of dense- and porous-microspheres and micron-sized spherical shells is very important in (a) the development of ceramics for structural, electronic, catalyst and thermal applications; and (b) the encapsulation of products for controlled-release of drugs, flavors and perfumes, and inks and dyes, and the protection of light-sensitive components and mechanical support of fragile materials. Larger metallic- and ceramic-spherical shells have been used in inertial confinement fusion (ICF) experiments and as catalyst supports. The current paper will focus on a recent technique that has been developed for synthesizing ceramic microspheres and micro-shells. Pulsed electric fields have been used to enhance the dispersion of aqueous metal (Zr and Al) salt solutions from a nozzle and into a nonconducting liquid continuous phase that is immiscible with the aqueous phase. The diameter of the resulting microdroplets ranged in size from approximately 0.1 to 10 μm. Precipitation of hydrous metal oxides occurred as ammonia, which was dissolved in varying amounts in the continuous phase, diffused into the aqueous microdroplets. Spherical shells were formed at higher ammonia concentrations and microspheres were produced at lower ammonia concentrations. Upon drying, dimples appeared in the particles that were synthesized at higher ammonia concentrations. The latter result accords with the well known fact that under certain conditions spherical shells collapse when a fluid is extracted from the core of the particle. No dimples were observed in the microspheres that were produced at lower ammonia concentrations. Analog X-ray dot maps for aluminum and zirconium were done to determine the spatial distribution of each metal in the particles

  18. Power output and efficiency of beta-emitting microspheres

    International Nuclear Information System (INIS)

    Cheneler, David; Ward, Michael

    2015-01-01

    Current standard methods to calculate the dose of radiation emitted during medical applications by beta-minus emitting microspheres rely on an over-simplistic formalism. This formalism is a function of the average activity of the radioisotope used and the physiological dimensions of the patient only. It neglects the variation in energy of the emitted beta particle due to self-attenuation, or self-absorption, effects related to the finite size of the sphere. Here it is assumed the sphere is comprised of a pure radioisotope with beta particles being emitted isotropically throughout the material. The full initial possible kinetic energy distribution of a beta particle is taken into account as well as the energy losses due to scattering by other atoms in the microsphere and bremsstrahlung radiation. By combining Longmire’s theory of the mean forward range of charged particles and the Rayleigh distribution to take into account the statistical nature of scattering and energy straggling, the linear attenuation, or self-absorption, coefficient for beta-emitting radioisotopes has been deduced. By analogy with gamma radiation transport in spheres, this result was used to calculate the rate of energy emitted by a beta-emitting microsphere and its efficiency. Comparisons to standard point dose kernel formulations generated using Monte Carlo data show the efficacy of the proposed method. Yttrium-90 is used as a specific example throughout, as a medically significant radioisotope, frequently used in radiation therapy for treating cancer. - Highlights: • Range-energy relationship for the beta particles in yttrium-90 is calculated. • Formalism for the semi-analytical calculation of self-absorption coefficients. • Energy-dependent self-absorption coefficient calculated for yttrium-90. • Flux rate of beta particles from a self-attenuating radioactive sphere is shown. • The efficiency of beta particle emitting radioactive microspheres is calculated

  19. Thermal conditions within tree cavities in ponderosa pine (Pinus ponderosa) forests: potential implications for cavity users

    Science.gov (United States)

    Vierling, Kerri T.; Lorenz, Teresa J.; Cunningham, Patrick; Potterf, Kelsi

    2017-11-01

    Tree cavities provide critical roosting and breeding sites for multiple species, and thermal environments in these cavities are important to understand. Our objectives were to (1) describe thermal characteristics in cavities between June 3 and August 9, 2014, and (2) investigate the environmental factors that influence cavity temperatures. We placed iButtons in 84 different cavities in ponderosa pine (Pinus ponderosa) forests in central Washington, and took hourly measurements for at least 8 days in each cavity. Temperatures above 40 °C are generally lethal to developing avian embryos, and 18% of the cavities had internal temperatures of ≥ 40 °C for at least 1 h of each day. We modeled daily maximum cavity temperature, the amplitude of daily cavity temperatures, and the difference between the mean internal cavity and mean ambient temperatures as a function of several environmental variables. These variables included canopy cover, tree diameter at cavity height, cavity volume, entrance area, the hardness of the cavity body, the hardness of the cavity sill (which is the wood below the cavity entrance which forms the barrier between the cavity and the external environment), and sill width. Ambient temperature had the largest effect size for maximum cavity temperature and amplitude. Larger trees with harder sills may provide more thermally stable cavity environments, and decayed sills were positively associated with maximum cavity temperatures. Summer temperatures are projected to increase in this region, and additional research is needed to determine how the thermal environments of cavities will influence species occupancy, breeding, and survival.

  20. Red-cockaded woodpecker nest-cavity selection: relationships with cavity age and resin production

    Science.gov (United States)

    Richard N. Conner; Daniel Saenz; D. Craig Rudolph; William G. Ross; David L. Kulhavy

    1998-01-01

    The authors evaluated selection of nest sites by male red-cockaded woodpeckers (Picoides borealis) in Texas relative to the age of the cavity when only cavities excavated by the woodpeckers were available and when both naturally excavated cavities and artificial cavities were available. They also evaluated nest-cavity selection relative to the ability of naturally...

  1. Sustained release of simvastatin from hollow carbonated hydroxyapatite microspheres prepared by aspartic acid and sodium dodecyl sulfate.

    Science.gov (United States)

    Wang, Ke; Wang, Yinjing; Zhao, Xu; Li, Yi; Yang, Tao; Zhang, Xue; Wu, Xiaoguang

    2017-06-01

    Hollow carbonated hydroxyapatite (HCHAp) microspheres as simvastatin (SV) sustained-release vehicles were fabricated through a novel and simple one-step biomimetic strategy. Firstly, hollow CaCO 3 microspheres were precipitated through the reaction of CaCl 2 with Na 2 CO 3 in the presence of aspartic acid and sodium dodecyl sulfate. Then, the as-prepared hollow CaCO 3 microspheres were transformed into HCHAp microspheres with a controlled anion-exchange method. The HCHAp microspheres were 3-5μm with a shell thickness of 0.5-1μm and were constructed of short needle nanoparticles. The HCHAp microspheres were then loaded with SV, exhibiting excellent drug-loading capacity and sustained release properties. These results present a new material synthesis strategy for HCHAp microspheres and suggest that the as-prepared HCHAp microspheres are promising for applications in drug delivery. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Kefiran-alginate gel microspheres for oral delivery of ciprofloxacin.

    Science.gov (United States)

    Blandón, Lina M; Islan, German A; Castro, Guillermo R; Noseda, Miguel D; Thomaz-Soccol, Vanete; Soccol, Carlos R

    2016-09-01

    Ciprofloxacin is a broad-spectrum antibiotic associated with gastric and intestinal side effects after extended oral administration. Alginate is a biopolymer commonly employed in gel synthesis by ionotropic gelation, but unstable in the presence of biological metal-chelating compounds and/or under dried conditions. Kefiran is a microbial biopolymer able to form gels with the advantage of displaying antimicrobial activity. In the present study, kefiran-alginate gel microspheres were developed to encapsulate ciprofloxacin for antimicrobial controlled release and enhanced bactericidal effect against common pathogens. Scanning electron microscopy (SEM) analysis of the hybrid gel microspheres showed a spherical structure with a smoother surface compared to alginate gel matrices. In vitro release of ciprofloxacin from kefiran-alginate microspheres was less than 3.0% and 5.0% at pH 1.2 (stomach), and 5.0% and 25.0% at pH 7.4 (intestine) in 3 and 21h, respectively. Fourier transform infrared spectroscopy (FTIR) of ciprofloxacin-kefiran showed the displacement of typical bands of ciprofloxacin and kefiran, suggesting a cooperative interaction by hydrogen bridges between both molecules. Additionally, the thermal analysis of ciprofloxacin-kefiran showed a protective effect of the biopolymer against ciprofloxacin degradation at high temperatures. Finally, antimicrobial assays of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhymurium, and Staphylococcus aureus demonstrated the synergic effect between ciprofloxacin and kefiran against the tested microorganisms. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Microspherical polyaniline/graphene nanocomposites for high performance supercapacitors

    Science.gov (United States)

    Cao, Hailiang; Zhou, Xufeng; Zhang, Yiming; Chen, Liang; Liu, Zhaoping

    2013-12-01

    Polyaniline/graphene nanocomposites with microspherical morphology and porous structure are prepared as electrode materials for supercapacitors. Using few-layer graphene obtained by liquid phase exfoliation of graphite as the raw material, porous graphene microspheres are produced by spray drying, and are then employed as the substrates for the growth of polyaniline nanowire arrays by in situ polymerization. In the composite, interconnected graphene sheets with few structural defects constitute a high-efficient conductive network to improve the electrical conductivity of polyaniline. Furthermore, the microspherical architecture prevents restacking of polyaniline/graphene composite nanosheets, thus facilitates fast diffusion of electrolytes. Consequently, the nanocomposite exhibits excellent electrochemical performance. A specific capacitance of 338 F g-1 is reached in 1 M H2SO4 at a scan rate of 20 mV s-1, and a high capacity retention rate of 87.4% after 10,000 cycles at a current density of 3 A g-1 can be achieved, which suggests that the polyaniline/graphene composite with such kind of 3D architecture is a promising electrode material for high-performance supercapacitors.

  4. Diclofenac salts, part 6: release from lipid microspheres.

    Science.gov (United States)

    Fini, Adamo; Cavallari, Cristina; Rabasco Alvarez, Antonio M; Rodriguez, Marisa Gonzalez

    2011-08-01

    The release of diclofenac (20%, w/w) was studied from lipidic solid dispersions using three different chemical forms (acid, sodium salt, and pyrrolidine ethanol salt) and two different lipid carriers (Compritol 888 ATO or Carnauba wax) either free or together with varying amounts (10%-30%, w/w) of stearic acid. Microspheres were prepared by ultrasound-assisted atomization of the molten dispersions and analyzed by scanning electron microscopy, differential scanning calorimetry, and hot stage microscopy. The effects of different formulations on the resulting drug release profiles as a function of pH were studied and the results were discussed. The formulation of the 18 systems and the chemical form of the drug were found to strongly affect the mode of the drug release. The solubility of the chemical forms in the lipid mixture is in the following order: pyrrolidine ethanol salt ≫ acid > sodium salt (according to the solubility parameters), and the nature of the systems thus obtained ranges from a matrix, for mutually soluble drug/carrier pairs, to a microcapsule, for pairs wherein mutual solubility is poor. Drug release from microspheres prepared by pure lipids was primarily controlled by diffusion, whereas the release from microspheres containing stearic acid was diffusion/erosion controlled at pH 7.4. Copyright © 2011 Wiley-Liss, Inc.

  5. Multiplex detection of plant pathogens using a microsphere immunoassay technology.

    Directory of Open Access Journals (Sweden)

    Ratthaphol Charlermroj

    Full Text Available Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac, chilli vein-banding mottle virus (CVbMV, potyvirus, watermelon silver mottle virus (WSMoV, tospovirus serogroup IV and melon yellow spot virus (MYSV, tospovirus. An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour was much shorter than that of ELISA (4 hours. This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection.

  6. Multiplex detection of plant pathogens using a microsphere immunoassay technology.

    Science.gov (United States)

    Charlermroj, Ratthaphol; Himananto, Orawan; Seepiban, Channarong; Kumpoosiri, Mallika; Warin, Nuchnard; Oplatowska, Michalina; Gajanandana, Oraprapai; Grant, Irene R; Karoonuthaisiri, Nitsara; Elliott, Christopher T

    2013-01-01

    Plant pathogens are a serious problem for seed export, plant disease control and plant quarantine. Rapid and accurate screening tests are urgently required to protect and prevent plant diseases spreading worldwide. A novel multiplex detection method was developed based on microsphere immunoassays to simultaneously detect four important plant pathogens: a fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac), chilli vein-banding mottle virus (CVbMV, potyvirus), watermelon silver mottle virus (WSMoV, tospovirus serogroup IV) and melon yellow spot virus (MYSV, tospovirus). An antibody for each plant pathogen was linked on a fluorescence-coded magnetic microsphere set which was used to capture corresponding pathogen. The presence of pathogens was detected by R-phycoerythrin (RPE)-labeled antibodies specific to the pathogens. The assay conditions were optimized by identifying appropriate antibody pairs, blocking buffer, concentration of RPE-labeled antibodies and assay time. Once conditions were optimized, the assay was able to detect all four plant pathogens precisely and accurately with substantially higher sensitivity than enzyme-linked immunosorbent assay (ELISA) when spiked in buffer and in healthy watermelon leaf extract. The assay time of the microsphere immunoassay (1 hour) was much shorter than that of ELISA (4 hours). This system was also shown to be capable of detecting the pathogens in naturally infected plant samples and is a major advancement in plant pathogen detection.

  7. Modified microspheres for cleaning liquid wastes from radioactive nuclides

    International Nuclear Information System (INIS)

    Danilin, Lev; Drozhzhin, Valery

    2007-01-01

    An effective solution of nuclear industry problems related to deactivation of technological and natural waters polluted with toxic and radioactive elements is the development of inorganic sorbents capable of not only withdrawing radioactive nuclides, but also of providing their subsequent conservation under conditions of long-term storage. A successful technical approach to creation of sorbents can be the use of hollow aluminosilicate microspheres. Such microspheres are formed from mineral additives during coal burning in furnaces of boiler units of electric power stations. Despite some reduction in exchange capacity per a mass unit of sorbents the latter have high kinetic characteristics that makes it possible to carry out the sorption process both in static and dynamic modes. Taking into account large industrial resources of microspheres as by-products of electric power stations, a comparative simplicity of the modification process, as well as good kinetic and capacitor characteristics, this class of sorbents can be considered promising enough for solving the problems of cleaning liquid radioactive wastes of various pollution levels. (authors)

  8. Quality Assurance Issues for Therapeutic Application of Radioactive Microspheres

    International Nuclear Information System (INIS)

    Dezarn, William A.

    2008-01-01

    The use of radioactive microspheres for the treatment of hepatic cancer is a procedure that raises unique quality assurance (QA) concerns. The greatest of these concerns is the coordination of the responsibilities among the medical team members from interventional radiology, radiation oncology, nuclear medicine, and medical physics. A single QA practice and procedure guidance document does not currently exist that addresses the range of issues of concern for radioactive microspheres. A small sampling of QA issues of concern include imaging QA, procedure-specific imaging protocols, detector calibration, activity measurement, radiation safety, patient dose calculations, and patient-specific QA. Some of the items listed have historically been the responsibility of a single team member, and other items have been concerns for all. A procedural overview of the therapeutic application of radioactive microspheres is presented to illustrate the broad, team-based QA approach necessary to safely and effectively deliver this type of treatment. From this overview, the reader will be able to customize the local QA protocol to meet the local division of responsibilities

  9. Recent progress on the fabrication of hollow microspheres

    International Nuclear Information System (INIS)

    Wang Aijuan; Lu Yupeng; Sun Ruixue

    2007-01-01

    Hollow microspheres represent a special class of materials, on which intense interest has been paid in the fields of material science, medicine, chemistry and chromatography. Several methods, including templating method, emulsion processing, high temperature smelting and layer-by-layer self-assembly technique, have been used to produce this kind of materials. However, most of the current needs for hollow microspheres are limited because of the disadvantages of these fabricating methods, such as time-consuming and relatively complex fabricating process. Spray drying method, as a simple and feasible technology, has also been used to fabricate this kind of materials. This method can improve the efficiency and save the time to some extent, and thus gains more and more interest recently. The factors of influencing the product morphology, including inlet air temperature, atomized pressure, feed rate, initial slurry concentration, primary powders size and additives, are reviewed in this paper. In addition, several kinds of typical hollow microspheres fabricated by this method are also listed particularly

  10. Magnetic microspheres as magical novel drug delivery system: A review

    Directory of Open Access Journals (Sweden)

    Satinder Kakar

    2013-01-01

    Full Text Available Magnetic microspheres hold great promise for reaching the goal of controlled and site specific drug delivery. Magnetic microspheres as an alternative to traditional radiation methods which uses highly penetrating radiations that is absorbed throughout the body. Its use is limited by toxicity and side effects. Now days, several targeted treatment systems including magnetic field, electric field, ultrasound, temperature, UV light and mechanical force are being used in many disease treatments (e.g. cancer, nerve damage, heart and artery, anti-diabetic, eye and other medical treatments. Among them, the magnetic targeted drug delivery system is one of the most attractive and promising strategy for delivering the drug to the specified site. Magnetically controlled drug targeting is one of the various possible ways of drug targeting. This technology is based on binding establish anticancer drug with ferrofluid that concentrate the drug in the area of interest (tumor site by means of magnetic fields. There has been keen interest in the development of a magnetically target drug delivery system. These drug delivery systems aim to deliver the drug at a rate directed by the needs of the body during the period of treatment, and target the activity entity to the site of action. Magnetic microspheres were developed to overcome two major problems encountered in drug targeting namely: RES clearance and target site specificity.

  11. CEBAF's SRF cavity manufacturing experience

    International Nuclear Information System (INIS)

    Benesch, J.F.; Reece, C.E.

    1994-01-01

    Construction of the Continuous Electron Beam Accelerator Facility (CEBAF) recirculating linac represents the largest scale application of superconducting rf (SRF) technology to date. The accelerating structures in CEBAF are 169 pairs of 1.5 GHz superconducting rf cavities -- 9 pairs in an injector and 80 pairs each in two linacs. The beam is to be recirculated up to five passes through each linac. Data is presented on mechanical tolerances achieved by the industrial fabricator of the rf cavities (Siemens). Liquid helium leak rates integrated over 22 vacuum seals have been measured on over 110 cavity pairs. A roughly normal distribution of the log 10 (leak rate) is seen, centered about a rate of 10 -10.4 torr-l/s. Over 140 pairs of the cavities have been assembled and have completed rf testing at 2.0 K. Among these, 54% demonstrated usable accelerating gradients greater than 10 MV/m. Although the rf performance characteristics well exceed the CEBAF baseline requirements of 5 MV/m at Q 0 = 2.4x10 9 , the usual limiting phenomena are encountered: field emission, quenching, and occasional multipacting. A discussion of the occurrence conditions and severity of these phenomena during production cavity testing is presented. The frequency with which performance is limited by quenching suggests that additional material advances may be required for applications which require the reliable achievement of accelerating gradients of more than 15 MV/m

  12. Coupling of an overdriven cavity

    International Nuclear Information System (INIS)

    Garbin, H.D.

    1993-01-01

    It is well known that when a nuclear test is conducted in a sufficiently large cavity, the resulting seismic signal is sharply reduced when compared to a normal tamped event. Cavity explosions are of interest in the seismic verification community because of this possibility of reducing the seismic energy generated which can lower signal amplitudes and make detection difficult. Reduced amplitudes would also lower seismic yield estimates which has implications in a Threshold Test Ban Treaty (TTBT). In the past several years, there have been a number of nuclear tests at NTS (Nevada Test Site) inside hemispherical cavities. Two such tests were MILL YARD and MISTY ECHO which had instrumentation at the surface and in the free-field. These two tests differ in one important aspect. MILL YARD was completely decoupled i.e., the cavity wall behaved in an elastic manner. It was estimated that MILL YARD's ground motion was reduced by a factor of at least 70. In contrast, MISTY ECHO was detonated in a hemispherical cavity with the same dimensions as MILL YARD, but with a much larger device yield. This caused an inelastic behavior on the wall and the explosion was not fully decoupled

  13. Development of Side Coupled Cavities

    International Nuclear Information System (INIS)

    Conto, J.M. de; Carretta, J.M.; Gomez-Martinez, Y.; Micoud, R.

    2008-01-01

    Side coupled Cavities are good candidates for proton accelerations in the 90-180 MeV range, as it has been first proposed for the CERN LINAC4 project. A side coupled Linac is made of a lump chain of resonant cavities, alternatively accelerating and coupling. A side coupled cavity has been designed in a CERN-LPSC collaboration to achieve LINAC4 requirements. After RF studies, a complete thermal study has been done, showing that 10-15% is the absolute maximum duty-cycle achievable by such a cavity. Error studies have been developed. They have shown that a tuning ring is mandatory and that a K equals 3% coupling factor is a good choice. A prototype has been built and each cell has been measured and tuned. A simple and accurate method has been used to get both the resonant frequency and the coupling factor, with a movable tuner and a linear fit. A similar method has been used to get the second order coupling factor. A large dispersion is observed on K. This is mainly due to the shape of the coupling apertures, which are very sensitive to mechanical errors. A future and realistic design must be very careful to guarantee a constant aperture (the important parameter is more the dispersion of k than its exact value). Finally, we analyse how to tune the cavity. This has to checked carefully and probably improved or corrected. Results are expected for mid-2008

  14. Performance test of a vertically-directed electric-field cavity resonator made for the rapid gelation apparatus with microwave heating

    International Nuclear Information System (INIS)

    Yamagishi, Shigeru; Ogawa, Toru; Hasegawa, Atsushi.

    1996-06-01

    A cavity resonator with vertically-directed electric field was produced and attached to 'the rapid gelation apparatus with microwave heating' previously reported. Using the rapid gelation apparatus, drops of a simulated solution and of U-containing solutions for internal gelation were heated. The results indicated that the heating required for gelation of the U-containing solutions was possible. However, the electric field strength in the cavity resonator at that time was comparable to that causing the discharge due to the gaseous ammonia released from the heated drops. As a result, gel microspheres were not obtained in a stable state. The discussion suggests that the stable gelation would be realized by improving the cavity resonator shape and/or by modifying the power supply accompanied with using a power stabilizer. (author)

  15. Polymer-coated albumin microspheres as carriers for intravascular tumour targeting of cisplatin.

    Science.gov (United States)

    Verrijk, R; Smolders, I J; McVie, J G; Begg, A C

    1991-01-01

    We used a poly-lactide-co-glycolide polymer (PLAGA 50:50) to formulate cisplatin (cDDP) into microspheres designed for intravascular administration. Two systems were developed. PLAGA-coated albumin microspheres and microspheres consisting of PLAGA only. PLAGA-coated microspheres displayed a mean diameter of 31.8 +/- 0.9 microns and a payload of 7.5% cDDP (w/w). Solid PLAGA microspheres exhibited a mean diameter of 19.4 +/- 0.6 microns and a payload of 20% cDDP. Release characteristics and in vitro effects on L1210 leukemia and B16 melanoma cell lines were investigated. Both types of microsphere overcame the initial rapid release of cDDP (burst effect), and PLAGA-coated albumin microspheres also showed a lag phase of approximately 30 min before cDDP release began. PLAGA-coated albumin microspheres released most of their payload through diffusion, and the coating eventually cracked after 7 days' incubation in saline supplemented with 0.1% Tween at 37 degrees C, enabling the release of any cDDP remaining. Effects of platinum, pre-released from PLAGA-coated albumin microspheres on the in vitro growth of L1210 cells were comparable with those of standard formulations (dissolved) of cDDP. Material released from non-drug-loaded PLAGA microspheres had no effect on L1210 cell growth, suggesting the absence of cytotoxic compounds in the matrix. The colony-forming ability of B16 cells was also equally inhibited by standard cDDP and pre-released drug. These studies show that formulation of cDDP in PLAGA-based microspheres prevents the rapid burst effect of cDDP seen in previous preparations and offers an improved system of administration for hepatic artery infusion or adjuvant therapy, enabling better clinical handling and the promise of a higher ratio of tumour tissue to normal tissue.

  16. Preparation of magnetic polylactic acid microspheres and investigation of its releasing property for loading curcumin

    Energy Technology Data Exchange (ETDEWEB)

    Li Fengxia [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China); Li Xiaoli, E-mail: lixiaoli0903@163.com [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China); Li Bin, E-mail: libinzh62@163.com [Heilongjiang Key Laboratory of Molecular Design and Preparation of Flame Retarded Materials, College of Science, Northeast Forestry University, Harbin 150040 (China)

    2011-11-15

    In order to obtain a targeting drug carrier system, magnetic polylactic acid (PLA) microspheres loading curcumin were synthesized by the classical oil-in-water emulsion solvent-evaporation method. In the Fourier transform infrared spectra of microspheres, the present functional groups of PLA were all kept invariably. The morphology and size distribution of magnetic microspheres were observed with scanning electron microscopy and dynamic light scattering, respectively. The results showed that the microspheres were regularly spherical and the surface was smooth with a diameter of 0.55-0.75 {mu}m. Magnetic Fe{sub 3}O{sub 4} was loaded in PLA microspheres and the content of magnetic particles was 12 wt% through thermogravimetric analysis. The magnetic property of prepared microspheres was measured by vibrating sample magnetometer. The results showed that the magnetic microspheres exhibited typical superparamagnetic behavior and the saturated magnetization was 14.38 emu/g. Through analysis of differential scanning calorimetry, the curcumin was in an amorphous state in the magnetic microspheres. The drug loading, encapsulation efficiency and releasing properties of curcumin in vitro were also investigated by ultraviolet-visible spectrum analysis. The results showed that the drug loading and encapsulation efficiency were 8.0% and 24.2%, respectively. And curcumin was obviously slowly released because the cumulative release percentage of magnetic microspheres in the phosphate buffer (pH=7.4) solution was only 49.01% in 72 h, and the basic release of curcumin finished in 120 h. - Highlights: > We prepare magnetic polylactic acid microspheres loading curcumin. > The classical oil-in-water emulsion solvent-evaporation method is used. > The magnetic microspheres are regularly spherical with a diameter of 0.55-0.75 {mu}m. > They show a certain sustained release effect on in vitro drug releasing.

  17. Mobilization of microspheres from a fractured soil during intermittent infiltration events

    Science.gov (United States)

    Mohanty, Sanjay; Bulicek, Mark; Metge, David W.; Harvey, Ronald W.; Ryan, Joseph N.; Boehm, Alexandria B.

    2015-01-01

    Pathogens or biocolloids mobilized in the vadose zone may consequently contaminate groundwater. We found that microspheres were mobilized from a fractured soil during intermittent rainfall and the mobilization was greater when the microsphere size was larger and when the soil had greater water permeability.The vadose zone filters pathogenic microbes from infiltrating water and consequently protects the groundwater from possible contamination. In some cases, however, the deposited microbes may be mobilized during rainfall and migrate into the groundwater. We examined the mobilization of microspheres, surrogates for microbes, in an intact core of a fractured soil by intermittent simulated rainfall. Fluorescent polystyrene microspheres of two sizes (0.5 and 1.8 mm) and Br− were first applied to the core to deposit the microspheres, and then the core was subjected to three intermittent infiltration events to mobilize the deposited microspheres. Collecting effluent samples through a 19-port sampler at the base of the core, we found that water flowed through only five ports, and the flow rates varied among the ports by a factor of 12. These results suggest that flow paths leading to the ports had different permeabilities, partly due to macropores. Although 40 to 69% of injected microspheres were retained in the core during their application, 12 to 30% of the retained microspheres were mobilized during three intermittent infiltration events. The extent of microsphere mobilization was greater in flow paths with greater permeability, which indicates that macropores could enhance colloid mobilization during intermittent infiltration events. In all ports, the 1.8-mm microspheres were mobilized to a greater extent than the 0.5-mm microspheres, suggesting that larger colloids are more likely to mobilize. These results are useful in assessing the potential of pathogen mobilization and colloid-facilitated transport of contaminants in the subsurface under natural infiltration

  18. Preparation of magnetic polylactic acid microspheres and investigation of its releasing property for loading curcumin

    International Nuclear Information System (INIS)

    Li Fengxia; Li Xiaoli; Li Bin

    2011-01-01

    In order to obtain a targeting drug carrier system, magnetic polylactic acid (PLA) microspheres loading curcumin were synthesized by the classical oil-in-water emulsion solvent-evaporation method. In the Fourier transform infrared spectra of microspheres, the present functional groups of PLA were all kept invariably. The morphology and size distribution of magnetic microspheres were observed with scanning electron microscopy and dynamic light scattering, respectively. The results showed that the microspheres were regularly spherical and the surface was smooth with a diameter of 0.55-0.75 μm. Magnetic Fe 3 O 4 was loaded in PLA microspheres and the content of magnetic particles was 12 wt% through thermogravimetric analysis. The magnetic property of prepared microspheres was measured by vibrating sample magnetometer. The results showed that the magnetic microspheres exhibited typical superparamagnetic behavior and the saturated magnetization was 14.38 emu/g. Through analysis of differential scanning calorimetry, the curcumin was in an amorphous state in the magnetic microspheres. The drug loading, encapsulation efficiency and releasing properties of curcumin in vitro were also investigated by ultraviolet-visible spectrum analysis. The results showed that the drug loading and encapsulation efficiency were 8.0% and 24.2%, respectively. And curcumin was obviously slowly released because the cumulative release percentage of magnetic microspheres in the phosphate buffer (pH=7.4) solution was only 49.01% in 72 h, and the basic release of curcumin finished in 120 h. - Highlights: → We prepare magnetic polylactic acid microspheres loading curcumin. → The classical oil-in-water emulsion solvent-evaporation method is used. → The magnetic microspheres are regularly spherical with a diameter of 0.55-0.75 μm. → They show a certain sustained release effect on in vitro drug releasing.

  19. High Q ceramics in the ACe2(MoO4)4 (A = Ba, Sr and Ca) system for LTCC applications

    International Nuclear Information System (INIS)

    Surjith, A.; Ratheesh, R.

    2013-01-01

    Highlights: ► Solid state synthesis of phase pure ACe 2 (MoO 4 ) 4 (A = Ba, Sr and Ca) ceramics. ► Structural and microstructural evaluation of the synthesized ceramic materials. ► Microwave dielectric property studies of ACe 2 (MoO 4 ) 4 (A = Ba, Sr and Ca) ceramics. ► Structure-property correlation through Laser Raman studies. - Abstract: Novel low temperature sinterable high Q ceramic systems ACe 2 (MoO 4 ) 4 (A = Ba, Sr and Ca) have been prepared through solid state ceramic method. The effect of ionic radii of alkaline earth cations on the structure, microstructure and microwave dielectric properties of these ceramics were studied using powder X-ray diffraction, Laser Raman spectroscopy, scanning electron microscopy and Vector Network Analyzer. A structural change from monoclinic to tetragonal structure was observed while substituting Sr 2+ and Ca 2+ cations in place of Ba 2+ . The Sr and Ca analogues possess better microwave dielectric properties compared to BaCe 2 (MoO 4 ) 4 . All the ceramics were well sintered below 840 °C with dielectric constant in the range 10.2–12.3 together with good quality factor. The SrCe 2 (MoO 4 ) 4 ceramic exhibits an unloaded quality factor of 6762 at 8.080662 GHz with a temperature coefficient of resonant frequency of −46 ppm/°C while the CaCe 2 (MoO 4 ) 4 ceramic shows an unloaded quality factor of 7549 at 6.928868 GHz and a temperature coefficient of resonant frequency of −44 ppm/°C.

  20. A SURVEY OF CORONAL CAVITY DENSITY PROFILES

    International Nuclear Information System (INIS)

    Fuller, J.; Gibson, S. E.

    2009-01-01

    Coronal cavities are common features of the solar corona that appear as darkened regions at the base of coronal helmet streamers in coronagraph images. Their darkened appearance indicates that they are regions of lowered density embedded within the comparatively higher density helmet streamer. Despite interfering projection effects of the surrounding helmet streamer (which we refer to as the cavity rim), Fuller et al. have shown that under certain conditions it is possible to use a Van de Hulst inversion of white-light polarized brightness (pB) data to calculate the electron density of both the cavity and cavity rim plasma. In this article, we apply minor modifications to the methods of Fuller et al. in order to improve the accuracy and versatility of the inversion process, and use the new methods to calculate density profiles for both the cavity and cavity rim in 24 cavity systems. We also examine trends in cavity morphology and how departures from the model geometry affect our density calculations. The density calculations reveal that in all 24 cases the cavity plasma has a flatter density profile than the plasma of the cavity rim, meaning that the cavity has a larger density depletion at low altitudes than it does at high altitudes. We find that the mean cavity density is over four times greater than that of a coronal hole at an altitude of 1.2 R sun and that every cavity in the sample is over twice as dense as a coronal hole at this altitude. Furthermore, we find that different cavity systems near solar maximum span a greater range in density at 1.2 R sun than do cavity systems near solar minimum, with a slight trend toward higher densities for systems nearer to solar maximum. Finally, we found no significant correlation of cavity density properties with cavity height-indeed, cavities show remarkably similar density depletions-except for the two smallest cavities that show significantly greater depletion.

  1. Review of cavity optomechanical cooling

    International Nuclear Information System (INIS)

    Liu Yong-Chun; Hu Yu-Wen; Xiao Yun-Feng; Wong Chee Wei

    2013-01-01

    Quantum manipulation of macroscopic mechanical systems is of great interest in both fundamental physics and applications ranging from high-precision metrology to quantum information processing. For these purposes, a crucial step is to cool the mechanical system to its quantum ground state. In this review, we focus on the cavity optomechanical cooling, which exploits the cavity enhanced interaction between optical field and mechanical motion to reduce the thermal noise. Recent remarkable theoretical and experimental efforts in this field have taken a major step forward in preparing the motional quantum ground state of mesoscopic mechanical systems. This review first describes the quantum theory of cavity optomechanical cooling, including quantum noise approach and covariance approach; then, the up-to-date experimental progresses are introduced. Finally, new cooling approaches are discussed along the directions of cooling in the strong coupling regime and cooling beyond the resolved sideband limit. (topical review - quantum information)

  2. Synthesis of plastic scintillation microspheres: Evaluation of scintillators

    International Nuclear Information System (INIS)

    Santiago, L.M.; Bagán, H.; Tarancón, A.; Garcia, J.F.

    2013-01-01

    The use of plastic scintillation microspheres (PSm) appear to be an alternative to liquid scintillation for the quantification of alpha and beta emitters because it does not generate mixed wastes after the measurement (organic and radioactive). In addition to routine radionuclide determinations, PSm can be used for further applications, e.g. for usage in a continuous monitoring equipment, for measurements of samples with a high salt concentration and for an extractive scintillation support which permits the separation, pre-concentration and measurement of the radionuclides without additional steps of elution and sample preparation. However, only a few manufacturers provide PSm, and the low number of regular suppliers reduces its availability and restricts the compositions and sizes available. In this article, a synthesis method based on the extraction/evaporation methodology has been developed and successfully used for the synthesis of plastic scintillation microspheres. Seven different compositions of plastic scintillation microspheres have been synthesised; PSm1 with polystyrene, PSm2 with 2,5-Diphenyloxazol(PPO), PSm3 with p-terphenyl (pT), PSm4 with PPO and 1,4-bis(5-phenyloxazol-2-yl) (POPOP), PSm5 pT and (1,4-bis [2-methylstyryl] benzene) (Bis-MSB), PSm6 with PPO, POPOP and naphthalene and PSm7 with pT, Bis-MSB and naphthalene. The synthesised plastic scintillation microspheres have been characterised in terms of their morphology, detection capabilities and alpha/beta separation capacity. The microspheres had a median diameter of approximately 130 μm. Maximum detection efficiency values were obtained for the PSm4 composition as follows 1.18% for 3 H, 51.2% for 14 C, 180.6% for 90 Sr/ 90 Y and 76.7% for 241 Am. Values of the SQP(E) parameter were approximately 790 for PSm4 and PSm5. These values show that the synthesised PSm exhibit good scintillation properties and that the spectra are at channel numbers higher than in commercial PSm. Finally, the addition

  3. On niobium sputter coated cavities

    International Nuclear Information System (INIS)

    Arnolds-Mayer, G.; Kaufmann, U.; Downar, H.

    1988-01-01

    To coat copper cavities with a thin film of niobium, facilities for electropolishing and sputter deposition have been installed at Dornier. Experiments have been performed on samples to optimize electropolishing and deposition parameters. In this paper, characteristics concerning surface properties, adhesion of the niobium film to the copper substrate, and film properties were studied on planar samples. A 1.5 GHz single cell cavity made from oxygen free high conductivity (OFHC) copper was sputter coated twice. First rf measurements were performed in the temperature range from 300 K to 2 K

  4. The influence of increased cross-linker chain length in thermosensitive microspheres on potential sun-protection activity

    OpenAIRE

    Musiał, Witold; Kokol, Vanja; Vončina, Bojana

    2012-01-01

    The sun protection should involve substances with protecting activity against both UVB and UVA radiation. In this research the evaluation of thermosensitive microspheres as potential molecules for sunscreen formulations was approached, using modified Boots star rating system. The microspheres, thermosensitive N-isopropylacrylamide derivatives, have potential protecting activity against UV radiation. The MX and DX microspheres, with ethylene glycol dimethacrylate and diethylene glycol dimethac...

  5. Soluble curcumin amalgamated chitosan microspheres augmented drug delivery and cytotoxicity in colon cancer cells: In vitro and in vivo study.

    Science.gov (United States)

    Jyoti, Kiran; Bhatia, Richa Kaur; Martis, Elvis A F; Coutinho, Evans C; Jain, Upendra Kumar; Chandra, Ramesh; Madan, Jitender

    2016-12-01

    In present investigation, initially curcumin was complexed with 2-HP-β-CD (curcumin-2-HP-β-CD-complex) in 1:1 ratio and later amalgamated with chitosan microspheres (curcumin-2-HP-β-CD-CMs) for selective delivery in colon only through oral route of administration. Various analytical, spectral and in-silico docking techniques revealed that the curcumin was deeply inserted in the 2-HP-β-CD cavity with apparent stability constant of 3.35×10 -3 M. Furthermore, the mean particle size of 6.8±2.6μm and +39.2±4.1mV surface charge of curcumin-2-HP-β-CD-complex-CMs in addition to encapsulation efficiency of about 79.8±6.3% exhibited that the tailored microspheres were optimum for colon delivery of curcumin. This was also demonstrated in dissolution testing and standard cell proliferation assay in which curcumin-2-HP-β-CD-complex-CMs exhibited maximum release in simulated colonic fluid (SCF, pH ∼7.0-8.0, almond emulsion-β-glucosidase) with improved therapeutic index in HT-29 cells. Consistently, curcumin-2-HP-β-CD-complex-CMs successively enhanced the colonic bio-distribution of curcumin by ∼8.36 folds as compared to curcumin suspension in preclinical pharmacokinetic studies. In conclusion, curcumin-2-HP-β-CD-complex-CMs warrant further in vivo tumor regression study to establish its therapeutic efficacy in experimental colon cancer. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Photocatalytic activities of heterostructured TiO2-graphene porous microspheres prepared by ultrasonic spray pyrolysis

    International Nuclear Information System (INIS)

    Yang, Jikai; Zhang, Xintong; Li, Bing; Liu, Hong; Sun, Panpan; Wang, Changhua; Wang, Lingling; Liu, Yichun

    2014-01-01

    Highlights: • USP method is used to prepare TiO 2 -graphene porous microspheres. • XPS shows GO sheets in the composites has been reduced to graphene. • TiO 2 -graphene microspheres display a red-shifted absorption edge. • PL spectra indicate graphene can accept the photoexcited electrons from TiO 2 . • TiO 2 -graphene shows higher photocatalytic activity than TiO 2 under solar light. -- Abstract: TiO 2 -graphene porous microspheres were prepared by ultrasonic spray pyrolysis (USP) of aqueous suspension of graphene oxide containing TiO 2 nanoparticles (Degussa P25). The composite microspheres were characterized with SEM, XPS, photoluminescence, Raman and UV–Vis absorption spectra. TiO 2 -graphene porous microspheres displayed higher photocatalytic activity for the degradation of methylene blue solution than pristine TiO 2 microspheres under the irradiation of Xe lamp, and the highest activity was obtained at a weight percentage of graphene around 1%. The effect of graphene on photocatalytic activity of porous microsphere was discussed in terms of the enhanced charge separation by TiO 2 -graphene heterojunction, increased absorption of the visible light, as well as the possible hindrance of mass transportation in microspheres

  7. Dual Drug Loaded Biodegradable Nanofibrous Microsphere for Improving Anti-Colon Cancer Activity

    Science.gov (United States)

    Fan, Rangrang; Li, Xiaoling; Deng, Jiaojiao; Gao, Xiang; Zhou, Liangxue; Zheng, Yu; Tong, Aiping; Zhang, Xiaoning; You, Chao; Guo, Gang

    2016-06-01

    One of the approaches being explored to increase antitumor activity of chemotherapeutics is to inject drug-loaded microspheres locally to specific anatomic sites, providing for a slow, long term release of a chemotherapeutic while minimizing systemic exposure. However, the used clinically drug carriers available at present have limitations, such as their low stability, renal clearance and residual surfactant. Here, we report docetaxel (DOC) and curcumin (CUR) loaded nanofibrous microspheres (DOC + CUR/nanofibrous microspheres), self-assembled from biodegradable PLA-PEO-PPO-PEO-PLA polymers as an injectable drug carrier without adding surfactant during the emulsification process. The obtained nanofibrous microspheres are composed entirely of nanofibers and have an open hole on the shell without the assistance of a template. It was shown that these DOC + CUR/nanofibrous microspheres could release curcumin and docetaxel slowly in vitro. The slow, sustained release of curcumin and docetaxel in vivo may help maintain local concentrations of active drug. The mechanism by which DOC + CUR/nanofibrous microspheres inhibit colorectal peritoneal carcinomatosis might involve increased induction of apoptosis in tumor cells and inhibition of tumor angiogenesis. In vitro and in vivo evaluations demonstrated efficacious synergistic antitumor effects against CT26 of curcumin and docetaxel combined nanofibrous microspheres. In conclusion, the dual drug loaded nanofibrous microspheres were considered potentially useful for treating abdominal metastases of colorectal cancer.

  8. Carbidopa/levodopa-loaded biodegradable microspheres: in vivo evaluation on experimental Parkinsonism in rats.

    Science.gov (United States)

    Arica, Betül; Kaş, H Süheyla; Moghdam, Amir; Akalan, Nejat; Hincal, A Atilla

    2005-02-16

    The purpose of this study was to prepare and characterize injectable carbidopa (CD)/levodopa (LD)-loaded Poly(L-lactides) (L-PLA), Poly(D,L-lactides) (D,L-PLA) and Poly(D,L-lactide-co-glycolide) (PLAGA) microspheres for the intracerebral treatment of Parkinson's disease. The microspheres were prepared by solvent evaporation method. The polymers' (L-PLA, D,L-PLA and PLAGA) concentrations were 10% (w/w) in the organic phase; the emulsifiers [sodium carboxymethylcellulose (NaCMC):sodium oleate (SO) and Polyvinyl alcohol (PVA):SO mixture (4:1 w/v)] concentrations were 0.75% in the aqueous phase. Microspheres were analyzed for morphological characteristics, size distribution, drug loading and in vitro release. The release profile of CD/LD from microspheres was characterized in the range of 12-35% within the first hour of the in vitro release experiment. The efficiency of CD- and LD-encapsulated microspheres to striatal transplantation and the altering of apomorphine-induced rotational behavior in the 6-hydroxydopamine (6-OHDA) unilaterally lesioned rat model were also tested. 6-OHDA/CD-LD-loaded microsphere groups exhibited lower rotation scores than 6-OHDA/Blank microsphere groups as early as 1 week postlesion. These benefits continued throughout the entire experimental period and they were statistically significant during the 1, 2 and 8 weeks (p<0.05). CD/LD-loaded microspheres were specifically prepared to apply as an injectable dosage forms for brain implantation.

  9. Influence of polymeric microspheres on the myocardial oxygen partial pressure in the beating heart of pigs.

    Science.gov (United States)

    Hiebl, B; Mrowietz, C; Lee, S; Braune, S; Knaut, M; Lendlein, A; Franke, R P; Jung, F

    2011-07-01

    Injection of labeled microspheres is an established method in animal models to analyze the capillary organ blood flow at different time points. However, the microspheres can lead to stenoses of the capillary lumen, which might affect tissue oxygen supply. Our study aimed to investigate the influence of repeated injections of microspheres into the left coronary artery on the tissue oxygen partial pressure (pO(2)) in the downstream supplied myocardium of Göttingen minipigs. Tests (n=6 pigs each) were performed with two differently sized microspheres (ø=10 ± 0.1 μm (M10) or ø=15 ± 0.15 μm (M15)) from polystyrene. The pO(2) was measured in the midmyocardium of the left and right ventricle for 6 min continuously after each of five injections (1 × 10(6) microspheres each). There was a time laps of 12 min between each injection. In addition, the influence of the carrier solution was analyzed solely in the identical time frame. pO(2) decreased significantly in the myocardial area supplied by the ramus interventricularis paraconalis after injection of M15 microspheres. In contrast, the application of the M10 microspheres did not change the myocardial pO(2). This finding suggests to use microspheres with diameters not exceeding 10 μm for the coronary blood flow assessment. Copyright © 2011 Elsevier Inc. All rights reserved.

  10. 5-Fluorouracil:carnauba wax microspheres for chemoembolization: an in vitro evaluation.

    Science.gov (United States)

    Benita, S; Zouai, O; Benoit, J P

    1986-09-01

    5-Fluorouracil:carnauba wax microspheres were prepared using a meltable dispersion process with the aid of a surfactant as a wetting agent. It was noted that only hydrophilic surfactants were able to wet the 5-fluorouracil and substantially increased its content in the microspheres. No marked effect was observed in the particle size distribution of the solid microspheres as a function of the nature of the surfactant. Increasing the stirring rate in the preparation process decreased, first, the mean droplet size of the emulsified melted dispersion in the vehicle during the heating process, and, consequently, the mean particle size of the solidified microspheres during the cooling process. 5-Fluorouracil cumulative release from the microspheres followed first-order kinetics, as shown by nonlinear regression analysis. Although the kinetic results were not indicative of the true release mechanism from a single microsphere, it was believed that 5-fluorouracil release from the microspheres was probably governed by a dissolution process, rather than by a leaching process through the carnauba wax microspheres.

  11. Effect of Fabrication Process Parameters on the Size of Gelatin/Nanohydroxyapatite Microspheres

    Directory of Open Access Journals (Sweden)

    S. Bagheri-Khoulenjani

    2009-12-01

    Full Text Available Nano-hydroxyapatite/gelatin (nHA/Ge microspheres are currently used in bone tissue engineering as bone filler. In this  study, the effect of fabrication process parameters on the particle size of nano-hydroxyapatite/gelatinmicrospheres was investigated. The nHA/Ge microspheres were fabricated using water in oil emulsion. In order to design an experimental design, a surface response model with 2 factors including the rate of shaking and water to oil volume ratio in 3 levels was applied. Particle size was evaluated by using an optical microscope. The morphology of microspheres and distribution of nano-particles within the microspheres were studied by using scanning electron microscope and Ca elemental map obtained from energy dispersive X-ray analysis (EDX, respectively. Statistical analysis of the results obtained from particle size measurements revealed that the rate of shaking has stronger influence on the particle size of microspheres. Morphological studies showed that the fabricated microspheres were spherical with smooth surface. Ca elemental map of the microspheres showed that nano-hydroxyapatite particles distributed uniformly within the microspheres.

  12. Chitosan and Nanohydroxyapatite Roles in Physical and Chemical Characteristics of Gelatin/Chitosan/Nanohydroxyapatite Microspheres

    Directory of Open Access Journals (Sweden)

    S. Bagheri-Khoulenjani

    2010-12-01

    Full Text Available The effects of chitosan/biopolymer (C/P and nanohydroxyapatite/ biopolymer (nHA/P weight ratios on particle size and its uniformity, cross-linking density and NH2 content of nano-hydroxyapatite/chitosan/gelatin (nHA/C/G microspheres were investigated. Microspheres were fabricated using water-in-oil emulsion. Cross-linking of microspheres was performed using water soluble carbodiimide. Particle size and its uniformity were evaluated using an optical microscope. The morphology of microspheres was studied by scanning electron microscopy. The obtained data from particle size measurements revealed that increments in C/P ratio increased the particle size while reducing its uniformity, and increased the NH2 content and cross linking density of the microspheres. It was shown that incremental increase in nHA/P ratio increased the particle size and its uniformity and reduced the NH2 content and cross-linking density of the microspheres.Morphological studies showed that the fabricated microspheres had spherical shape in medium level of C/P ratio and nHA/P ratio. However, increasing in chitosan/biopolymer ratio induced some micro-cracks into the structure of microspheres.

  13. Kinetics of piroxicam release from low-methylated pectin/zein hydrogel microspheres

    Science.gov (United States)

    The kinetics of a model drug (piroxicam) release from pectin/zein hydrogel microspheres was studied under conditions simulating the gastrointestinal tract. It is established that the rate-limiting step in the release mechanism is drug diffusion out of the microspheres rather than its dissolution. ...

  14. Eudragit-coated dextran microspheres of 5-fluorouracil for site-specific delivery to colon.

    Science.gov (United States)

    Rai, Gopal; Yadav, Awesh K; Jain, Narendra K; Agrawal, Govind P

    2016-01-01

    Objective of the present investigation was to prepare and evaluate the potential of enteric coated dextran microspheres for colon targeting of 5-fluorouracil (5-FU). Dextran microspheres were prepared by emulsification-crosslinking method and the formulation variables studied included different molecular weights of dextran, drug:polymer ratio, volume of crosslinking agent, stirring speed and time. Enteric coating (Eudragit S-100) of dextran microspheres was performed by oil-in-oil solvent evaporation method using different coat:core ratios (4:1 or 8:1). Uncoated and coated dextran microspheres were characterized by particle size, surface morphology, entrapment efficiency, DSC, in vitro drug release in the presence of dextranase and 2% rat cecal contents. The release study of 5-FU from coated dextran microspheres was pH dependent. No release was observed at acidic pH; however, the drug was released quickly where Eudragit starts solublizing there was continuous release of drug from the microspheres. Organ distribution study was suggested that coated dextran microspheres retard the release of drug in gastric and intestinal pH environment and released of drug from microspheres in colon due to the degradation of dextran by colonic enzymes.

  15. Enteric-coated epichlorohydrin crosslinked dextran microspheres for site-specific delivery to colon.

    Science.gov (United States)

    Rai, Gopal; Yadav, Awesh K; Jain, Narendra K; Agrawal, Govind P

    2015-01-01

    Enteric-coated epichlorohydrin crosslinked dextran microspheres containing 5-Fluorouracil (5-FU) for colon drug delivery was prepared by emulsification-crosslinking method. The formulation variables studied includes different molecular weights of dextran, volume of crosslinking agent, stirring speed, time and temperature. Dextran microspheres showed mean entrapment efficiencies ranging between 77 and 87% and mean particle size ranging between 10 and 25 µm. About 90% of drug was released from uncoated dextran microspheres within 8 h, suggesting the fast release and indicated the drug loaded in uncoated microspheres, released before they reached colon. Enteric coating (Eudragit-S-100 and Eudragit-L-100) of dextran microspheres was performed by oil-in-oil solvent evaporation method. The release study of 5-FU from coated dextran microspheres was complete retardation in simulated gastric fluid (pH 1.2) and once the coating layer of enteric polymer was dissolved at higher pH (7.4 and 6.8), a controlled release of the drug from the microspheres was observed. Further, the release of drug was found to be higher in the presence of dextranase and rat caecal contents, indicating the susceptibility of dextran microspheres to colonic enzymes. Organ distribution and pharmacokinetic study in albino rats was performed to establish the targeting potential of optimized formulation in the colon.

  16. Multiplexed fluorescent microarray for human salivary protein analysis using polymer microspheres and fiber-optic bundles.

    Science.gov (United States)

    Nie, Shuai; Benito-Peña, Elena; Zhang, Huaibin; Wu, Yue; Walt, David R

    2013-10-10

    Herein, we describe a protocol for simultaneously measuring six proteins in saliva using a fiber-optic microsphere-based antibody array. The immuno-array technology employed combines the advantages of microsphere-based suspension array fabrication with the use of fluorescence microscopy. As described in the video protocol, commercially available 4.5 μm polymer microspheres were encoded into seven different types, differentiated by the concentration of two fluorescent dyes physically trapped inside the microspheres. The encoded microspheres containing surface carboxyl groups were modified with monoclonal capture antibodies through EDC/NHS coupling chemistry. To assemble the protein microarray, the different types of encoded and functionalized microspheres were mixed and randomly deposited in 4.5 μm microwells, which were chemically etched at the proximal end of a fiber-optic bundle. The fiber-optic bundle was used as both a carrier and for imaging the microspheres. Once assembled, the microarray was used to capture proteins in the saliva supernatant collected from the clinic. The detection was based on a sandwich immunoassay using a mixture of biotinylated detection antibodies for different analytes with a streptavidin-conjugated fluorescent probe, R-phycoerythrin. The microarray was imaged by fluorescence microscopy in three different channels, two for microsphere registration and one for the assay signal. The fluorescence micrographs were then decoded and analyzed using a homemade algorithm in MATLAB.

  17. Preparation and Comparative Bioavailability Studies of Indomethacin-Loaded Cetyl Alcohol Microspheres

    Directory of Open Access Journals (Sweden)

    N. Vishal Gupta

    2013-01-01

    Full Text Available The purpose of the present study was to compare the in vitro release and to find out whether the bioavailability of a 75 mg indomethacin capsule (Microcid SR was equivalent to optimized formulation (indomethacin-loaded cetyl alcohol microspheres. Indomethacin-loaded cetyl alcohol microspheres were prepared by meltable emulsified cooling-induced technique. Surface morphology of microspheres has been evaluated using scanning electron microscopy. A single dose, randomized, complete cross over study of IM microspheres was carried out on 10 healthy male and female Albino sheep’s under fasting conditions. The plasma was separated and the concentrations of the drug were determined by HPLC-UV method. Plasma indomethacin concentrations and other pharmacokinetic parameters obtained were statistically analyzed. The SEM images revealed the spherical shape of fat microspheres, and more than 98.0% of the isolated microspheres were in the size range 12–32 μm. DSC, FTIR spectroscopy and stability studies indicated that the drug after encapsulation with fat microspheres was stable and compatible. Both formulations were found to be bioequivalent as evidenced by in vivo studies. Based on this study, it can be concluded that cetyl alcohol microspheres and Microcid SR capsule are bioequivalent in terms of the rate and extent of absorption.

  18. ADRIAMYCIN-LOADED ALBUMIN-HEPARIN CONJUGATE MICROSPHERES FOR INTRAPERITONEAL CHEMOTHERAPY

    NARCIS (Netherlands)

    CREMERS, HFM; SEYMOUR, LW; LAM, K; LOS, G; KWON, G; BAE, YH; KIM, SW; FEIJEN, J

    1994-01-01

    Adriamycin-loaded albumin-heparin conjugate microspheres (ADR-AHCMS) were evaluated as possible intraperitoneal (i.p.) delivery systems for site-specific cytotoxic action. The biocompatibility of the microspheres after intraperitoneal injection was tested first. 1 day after i.p. administration of

  19. A Comparative Study of Production of Glass Microspheres by using Thermal Process

    Science.gov (United States)

    Lee, May Yan; Tan, Jully; Heng, Jerry YY; Cheeseman, Christopher

    2017-06-01

    Microspheres are spherical particles that can be distinguished into two categories; solid or hollow. Microspheres typical ranges from 1 to 200 μm in diameter. Microsphere are made from glass, ceramic, carbon or plastic depending on applications. Solid glass microsphere is manufactured by direct burning of glass powders while hollow glass microspheres is produced by adding blowing agent to glass powder. This paper presented the production of glass microspheres by using the vertical thermal flame (VTF) process. Pre-treated soda lime glass powder with particle sized range from 90 to 125μm was used in this work. The results showed that glass microspheres produced by two passes through the flame have a more spherical shape as compared with the single pass. Under the Scanning Electron Microscope (SEM), it is observed that there is a morphology changed from uneven surface of glass powders to smooth spherical surface particles. Qualitative analysis for density of the pre-burned and burned particles was performed. Burned particles floats in water while pre-burned particles sank indicated the change of density of the particles. Further improvements of the VTF process in terms of the VTF set-up are required to increase the transformation of glass powders to glass microspheres.

  20. Release of proteins via ion exchange from albumin-heparin microspheres

    NARCIS (Netherlands)

    Kwon, Glen S.; Bae, You Han; Cremers, H.F.M.; Cremers, Harry; Feijen, Jan; Kim, Sung Wan

    1992-01-01

    Albumin-heparin and albumin microspheres were prepared as ion exchange gels for the controlled release of positively charged polypeptides and proteins. The adsorption isotherms of chicken egg and human lysozyme, as model proteins, on microspheres were obtained. An adsorption isotherm of chicken egg