Optimization of magnetic field for CR dipole magnet

High homogeneity of the CR (collector ring) dipole magnet for FAIR (Facility for Antiproton and Ion Research) project at GSI is essential. The two optimized and analysis methods are introduced in detail. In order to obtain an ideal integral magnetic field distribution, the complicated end chamfer has been designed. By chamfering the removable pole, the distribution tolerance of high magnetic field is optimized to +/- 2 x 10(-4). The method of adding a mirror plane is suitable for the high magnetic field and it doesn't fit the low one. The OPERA is used to optimize the dipole magnetic field.

Structure analysis of the SECRAL superconducting magnet system

An advanced superconducting ECR ion source named SECRAL has been constructed at Institute of Modern Physics of Chinese Academy of Sciences, whose superconducting magnet assembly consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamp. In order to investigate the structure of sextupole coils and to increase the structural reliabilities of the magnet system, global and local structural analysis have been performed in various operation scenarios. Winding pack and support structure design of magnet system, mechanical calculation and stress analysis are given in this paper. From the analysis results, it has been found that the magnet system is safe in the referential operation scenarios and the configuration of the magnet complies with design requirements of the SECRAL.

Test and analysis of uniform magnetic fields for imaging of electrons produced in ion-atom collisions

In order to expand the solid angle for imaging of electrons in ion-atom collisions, we designed a complex Helmholtz coils composed of four single coils. Theoretical simulations were carried out to optimize the arrangement of the coils. The complex is constructed according to the theoretical analysis, and the magnetic fields were measured for interested regions. The measured results show that the relative uniformity of the magnetic fields is +/- 0.6%, which satisfies the requirements of collision experiments.

Relativistic Mean Field Study of the Z=117 Isotopic Chain

The properties of the Z = 117 isotopic chain are studied within the framework of the axially deformed relativistic mean field theory (RMFT) in the blocked BCS approximation. The ground-state properties, such as binging energies, deformations as well as the possible.. decay energies and lifetimes are calculated with the parameter set of NL-Z2 and compared with results from the finite range droplet model. The analysis by RMFT shows that the isotopes in the range of mass number A = 291 similar to 300 exhibit higher stability, which suggests that they may be promising nuclei to be hopefully synthesized in the lab among the nuclei Z = 117.

Stress Analysis of the Superconducting Magnet of LPT

The superconducting magnet of the LPT (Lanzhou Penning trap) consists of nine coaxial coils. The maximum magnetic field is 7 T and thus results in a large magnetic force. In order to assure the mechanical stability, it is necessary to do the stress analysis of the magnet system. The 3D Finite Element Analysis of thermal and mechanical behavior was presented in this paper. For the numerical simulation and analysis of the phenomena inside the structure, the ADINA and TOSCA code were chosen right from start. The ADINA code is commonly used for numerical simulations of the structure analysis [1] and the TOSCA code is professional software to calculate the magnetic field and Lorentz Forces. The results of the analysis were evaluated in terms of the stress and deformation.

Non-goal scene analysis for soccer video

The broadcast soccer video is usually recorded by one main camera, which is constantly gazing somewhere of playfield where a highlight event is happening. So the camera parameters and their variety have close relationship with semantic information of soccer video, and much interest has been caught in camera calibration for soccer video. The previous calibration methods either deal with goal scene, or have strict calibration conditions and high complexity. So, it does not properly handle the non-goal scene such as midfield or center-forward scene. In this paper, based on a new soccer field model, a field symbol extraction algorithm is proposed to extract the calibration information. Then a two-stage calibration approach is developed which can calibrate camera not only for goal scene but also for non-goal scene. The preliminary experimental results demonstrate its robustness and accuracy. (c) 2010 Elsevier B.V. All rights reserved.

Investigation on internal electric field distribution of organic light-emitting diodes (OLEDs) with Eu2O3 buffer layer

We have found that organic light-emitting diode (OLED) performance was highly improved by using europium oxide (Eu2O3) as a buffer layer on indium tin oxide (ITO) in OLEDs based on tris-(8-hydroxyquinoline) aluminium (Alq(3)), which showed low turn-on voltage, high luminance, and high electroluminescent (EL) efficiency. The thickness of Eu2O3 generally was 0.5-1.5 nm. We investigated the effects of Eu2O3 on internal electric field distributions in the device through the analysis of current-voltage characteristics, and found that the introduction of the buffer layer balanced the internal electric field distributions in hole transport layer (HTL) and electron transport layer (ETL), which should fully explain the role of the buffer layer in improving device performance. Our investigation demonstrates that the hole injection is Fowler-Nordheim (FN) tunnelling and the electron injection is Richardson-Schottky (RS) thermionic emission, which are very significant in understanding the operational mechanism and improving the performance, of OLEDs.

Short-capillary electrophoresis with electrochemiluminescence detection using porous etched joint for fast analysis of lidocaine and ofloxacin

Fast analysis of ofloxacin and lidocaine, as bactericide and analgesic or anesthetics, is of clinic importance for understanding the patient's medical process. This paper presented a high throughput, simple analysis method of lidocaine and ofloxacin by capillary electrophoresis coupled with electrochemiluminescence (ECL) using porous etched joint. To shorten the analysis time and to improve the analytical performance, a capillary with 10 cm in length was used as the separation channel. The cyclic voltammograms of Ru(bpy)(3)(2+) with different capillary length at same field strength showed that the porous etched joint eliminated the effect of electrophoretic current on the ECL detection. Following micro total analysis systems (muTAS), some advantages of which this approach has, the fabrication of channel in chip was not needed. Compared with capillary electrophoresis with 40-cm-long capillary, the high sample throughput and low zone broadening may be the main advantage of the present system. Under optimal condition, the detection limits of lidocaine and ofloxacin based on peak height were 3.0 x 10(-8) and 5.0 x 10(-7) mot L-1 and a 60 h(-1) of sampling frequency was obtained.

Structural analysis of saponins from medicinal herbs using electrospray ionization tandem mass spectrometry

The underivatized saponins from Tribulus terrestris and Panax ginseng have been investigated by electrospray ionization multi-stage tandem mass spectrometry (ESI-MSn). In ESI-MS spectra, a predominant [M + Na](+) ion in positive mode and [M - H](-) ion in negative mode were observed for molecular mass information. Multi-stage tandem mass spectrometry of the molecular ions was used for detailed structural analysis. Fragment ions from glycoside cleavage can provide information on the mass of aglycone and the primary sequence and branching of oligosaccharide chains in terms of classes of monosaccharides. Fragment ions from cross-ring cleavages of sugar residues can give some information about the linkages between sugar residues. It was found that different alkali metal-cationized adducts with saponins have different degrees of fragmentation, which may originate from the different affinity of a saponin with each alkali metal in the gas phase. ESI-MSn has been proven to be an effective tool for rapid determination of native saponins in extract mixtures, thus avoiding tedious derivatization and separation steps.

An investigation of low-field magnetoresistance in the double perovskites Sr2Fe1-xZnxMoO6, x=0, 0.05, 0.15 and 0.25

The electrical, magnetic and transport properties of Zn doped polycrystalline samples of Sr2Fe1-xZnxMoO6 ( x = 0, 0.05, 0.15 and 0.25) with the double perovskite structure have been investigated. The subtle replacement of Fe3+ ions by Zn2+ ions facilitates the formation of a more ordered structure, while further substitution leads to disordered structure because of the presence of a striped phase. Analysis of the x-ray powder diffraction patterns based on Rietveld analysis indicates that the replacement of Fe3+ by Zn2+ ions favours the formation of Mo6+ ions. The spin-glass behaviour can be explained on the basis of the competition between the antiferromagnetic superexchange and the ferromagnetic double-exchange interaction. The low-field magnetoresistance was moderately enhanced at x = 0.05, and its origin was found to be the competition between the decrease of the concentration of the itinerant electrons and the weaker antiferromagnetic superexchange in the antiphase boundaries. An almost linear negative magnetoresistance in moderate field has been observed for x = 0.25. A possible double-exchange mechanism is proposed for elucidating the observations; it also suggests a coexistence of (Fe3+, Mo5+) and (Zn2+, Mo6+) valence pairs.

Synthesis and characterization of spherical Sr2CeO4 phosphors by spray pyrolysis for field emission displays

A blue emitting Sr2CeO4 phosphor with a one-dimensional structure has been prepared by a two-step spray pyrolysis (SP) method, starting from the aqueous solutions of metal nitrates with citric acid and polyethylene glycol (PEG) as additives. The material is ultimately designed for field emission displays (FEDs). X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG-DTA), field emission scanning electron microscope pictures (FE-SEM) as well as photoluminescence (PL) and cathodoluminescence (CL) spectroscopy and lifetime measurements have been employed to characterize the samples. The morphology, PL and low voltage CL properties of Sr2CeO4 phosphors as-prepared using the SP method have been investigated by changing the concentration of the precursor solution, concentration of PEG, annealing temperature, acceleration voltage and filament current. The obtained Sr2CeO4 phosphor particles are spherical and of submicron size, 0.5-2 mu m. The emission spectrum of the phosphors shows a broad band with maximum at 467 nm (lifetime = 37.4 mu s; CIE chromaticity coordinates: x = 0.15 and y = 0.21), presumably due to a ligand-to-metal charge-transfer transition.

Correlation analysis of the structures and pK(a) values of carboxylic acids

The quantum-chemical descriptors were used for QSPR study of the structures of carboxylic acids and their pK(a) values. The algorithm of "Leaps and Bounds" regression was performed for selection of the variables. The CoMFA method was carried out for 3D-QSPR. As the introduction of the charge of oxygen atom(Q(2)), the results obtained by CoMFA were improved greatly.

External field induced crystallization of poly(3-dodecylthiophene)

In order to investigate the effect of external field on the crystallization behavior of poly(3-dodecylthiopliene) (P3DDT), the samples were recrystallized with different electrostatic field intensity, different pressure and different solidification direction in temperature gradient field. Measurements of differential scanning calorimetry and X-ray diffraction were operated to characterize these samples for analysis. The results suggest that after recrystallization, whether the external field is added or not, a more compact packing of molecular chains in P3DDT could be obtained without the change of the crystal structure model. Moreover, the addition of electrostatic field has greater effects on the crystallization of rigid main chains than on that of flexible side chains, Merely great pressure field can effect the rearrangements of molecular chains greatly. As for the temperature gradient field induced crystallization, different oriented solidification direction will lead to different effects on the compact degree and perfect degree of molecular chains packing,

Quantitative structure-property relationship research to the analysis of photoionization sensitivity of organic compounds in gas chromatography

The A(m) index and molecular connectivity index were used for studying the photoionization sensitivity of some organic compounds in gas chromatography. The analysis of structure-property relationship between the photoionization sensitivity of the compounds and the A(m) indices or molecular connectivity indices has been carried out. The genetic algorighm was used to build the correlation model in this field. The results demonstrate that the property of compounds can be described by both A(m) indices and molecular connectivity indices, and the mathematical model obtained by the genetic algorithm was better than that by multivariate regression analysis.

Magnetic microsphere and its use in biochemical separation and analysis

Magnetic microsphere comprises a magnetically responsive metal or metal oxide core surrounded by a polymer shell with active groups. Nowadays, methods of directly coating polymer, monomer polymerazation, impregnation, extrusion and biological synthesis are generally used to prepare magnetic particles. This kind of superparamagnetic microspheres can be attached to chemical, biochemical and biological substances by their active groups, then applying a magnetic field to separate from the media. Preparation and utilization of magnetic microspheres in immunoassay, nucleic acid hybrization assay, gene sequencing, cell isolation, enzyme immoblization, receptor isolation and other Gelds are reviewed with 44 references in this paper. Also, the further development is outlooked.