Edge Effects in Line Intersect Sampling With

Science.gov (United States)

David L. R. Affleck; Timothy G. Gregoire; Harry T. Valentine

2005-01-01

Transects consisting of multiple, connected segments with a prescribed configuration are commonly used in ecological applications of line intersect sampling. The transect configuration has implications for the probability with which population elements are selected and for how the selection probabilities can be modified by the boundary of the tract being sampled. As...

Center Line Slope Analysis in Two-Dimensional Electronic Spectroscopy

OpenAIRE

?anda, Franti?ek; Perl?k, V?clav; Lincoln, Craig N.; Hauer, J?rgen

2015-01-01

Center line slope (CLS) analysis in 2D infrared spectroscopy has been extensively used to extract frequency?frequency correlation functions of vibrational transitions. We apply this concept to 2D electronic spectroscopy, where CLS is a measure of electronic gap fluctuations. The two domains, infrared and electronic, possess differences: In the infrared, the frequency fluctuations are classical, often slow and Gaussian. In contrast, electronic spectra are subject to fast spectral diffusion and...

Electron diffraction patterns with thermal diffuse scattering maxima around Kikuchi lines

International Nuclear Information System (INIS)

Karakhanyan, R. K.; Karakhanyan, K. R.

2011-01-01

Transmission electron diffraction patterns of silicon with thermal diffuse maxima around Kikuchi lines, which are analogs of the maxima of thermal diffuse electron scattering around point reflections, have been recorded. Diffuse maxima are observed only around Kikuchi lines with indices that are forbidden for the silicon structure. The diffraction conditions for forming these maxima are discussed.

Electron polar cap and the boundary of open geomagnetic field lines.

Science.gov (United States)

Evans, L. C.; Stone, E. C.

1972-01-01

A total of 333 observations of the boundary of the polar access region for electrons (energies greater than 530 keV) provides a comprehensive map of the electron polar cap. The boundary of the electron polar cap, which should occur at the latitude separating open and closed field lines, is consistent with previously reported closed field line limits determined from trapped-particle data. The boundary, which is sharply defined, seems to occur at one of three discrete latitudes. Although the electron flux is generally uniform across the polar cap, a limited region of reduced access is observed about 10% of the time.

Virtual rough samples to test 3D nanometer-scale scanning electron microscopy stereo photogrammetry.

Science.gov (United States)

Villarrubia, J S; Tondare, V N; Vladár, A E

2016-01-01

The combination of scanning electron microscopy for high spatial resolution, images from multiple angles to provide 3D information, and commercially available stereo photogrammetry software for 3D reconstruction offers promise for nanometer-scale dimensional metrology in 3D. A method is described to test 3D photogrammetry software by the use of virtual samples-mathematical samples from which simulated images are made for use as inputs to the software under test. The virtual sample is constructed by wrapping a rough skin with any desired power spectral density around a smooth near-trapezoidal line with rounded top corners. Reconstruction is performed with images simulated from different angular viewpoints. The software's reconstructed 3D model is then compared to the known geometry of the virtual sample. Three commercial photogrammetry software packages were tested. Two of them produced results for line height and width that were within close to 1 nm of the correct values. All of the packages exhibited some difficulty in reconstructing details of the surface roughness.

Composition quantification of electron-transparent samples by backscattered electron imaging in scanning electron microscopy

Energy Technology Data Exchange (ETDEWEB)

Müller, E., E-mail: erich.mueller@kit.edu; Gerthsen, D.

2017-02-15

The contrast of backscattered electron (BSE) images in scanning electron microscopy (SEM) depends on material parameters which can be exploited for composition quantification if some information on the material system is available. As an example, the In-concentration in thin In{sub x}Ga{sub 1−x}As layers embedded in a GaAs matrix is analyzed in this work. The spatial resolution of the technique is improved by using thin electron-transparent specimens instead of bulk samples. Although the BSEs are detected in a comparably small angular range by an annular semiconductor detector, the image intensity can be evaluated to determine the composition and local thickness of the specimen. The measured intensities are calibrated within one single image to eliminate the influence of the detection and amplification system. Quantification is performed by comparison of experimental and calculated data. Instead of using time-consuming Monte-Carlo simulations, an analytical model is applied for BSE-intensity calculations which considers single electron scattering and electron diffusion. - Highlights: • Sample thickness and composition are quantified by backscattered electron imaging. • A thin sample is used to achieve spatial resolution of few nanometers. • Calculations are carried out with a time-saving electron diffusion model. • Small differences in atomic number and density detected at low electron energies.

Coronal Magnetic Field Lines and Electrons Associated with Type III

Indian Academy of Sciences (India)

Coronal Magnetic Field Lines and Electrons Associated with Type III–V Radio Bursts in a Solar Flare ... velocities of the electron streams associated with the above two types of bursts indicate ... Journal of Astrophysics and Astronomy | News ...

Spectral line shape simulation for electron stark-broadening of ion emitters in plasmas

International Nuclear Information System (INIS)

Dufour, Emmanuelle; Calisti, Annette; Talin, Bernard; Gigosos, Marco A.; Gonzalez, Manuel A.; Dufty, Jim W.

2002-01-01

Electron broadening for ions in plasmas is investigated in the framework of a simplified semi-classical model involving an ionic emitter imbedded in an electron gas. A regularized Coulomb potential that removes the divergence at short distances is postulated for the ion-electron interaction. Line shape simulations based on Molecular Dynamics for the ion impurity and the electrons, accounting for all the correlations, are reported. Comparisons with line shapes obtained with a quasi-particle model show expected correlation effects. Through an analysis of the results with the line shape code PPP, it is inferred that the correlation effect results mainly from the microfield dynamic properties

Path integral approach for electron transport in disturbed magnetic field lines

Energy Technology Data Exchange (ETDEWEB)

Kanno, Ryutaro; Nakajima, Noriyoshi; Takamaru, Hisanori

2002-05-01

A path integral method is developed to investigate statistical property of an electron transport described as a Langevin equation in a statically disturbed magnetic field line structure; especially a transition probability of electrons strongly tied to field lines is considered. The path integral method has advantages that 1) it does not include intrinsically a growing numerical error of an orbit, which is caused by evolution of the Langevin equation under a finite calculation accuracy in a chaotic field line structure, and 2) it gives a method of understanding the qualitative content of the Langevin equation and assists to expect statistical property of the transport. Monte Carlo calculations of the electron distributions under both effects of chaotic field lines and collisions are demonstrated to comprehend above advantages through some examples. The mathematical techniques are useful to study statistical properties of various phenomena described as Langevin equations in general. By using parallel generators of random numbers, the Monte Carlo scheme to calculate a transition probability can be suitable for a parallel computation. (author)

Oxygen consumption by hydrazine in long sample lines

International Nuclear Information System (INIS)

Chi, Lisheng; Turner, Carl-W.

2012-09-01

In nuclear power plants secondary side system dissolved oxygen concentration is a strictly controlled chemistry parameter intended to minimize corrosion and fouling of steam cycle components. Low dissolved oxygen concentration is maintained by a combination of mechanical de-aeration and chemical reaction. The dissolved oxygen concentration in feedwater is monitored by sampling systems to ensure it remains within station specification during operation. The sample lines in a nuclear power plant's sampling system can be from 5 to nearly 200 meters in length, resulting in sample residence times between the take-off point to the analyzer from a few seconds to several minutes, depending on the flow rate and the length of the sample line. For many chemical parameters the residence time is of no concern. For measurements of dissolved oxygen and hydrazine in the secondary coolant, however, for residence times longer than one minute, it is uncertain whether the sample is representative of conditions in the secondary coolant, especially for samples taken from locations where the temperature is well over 100 deg. C. To address this concern, a series of tests were conducted under both warm-up and power operation conditions, respectively, to investigate the effect of temperature, residence time, sample line length, surface area, hydrazine-to-oxygen ratio, and the concentrations of dissolved oxygen and hydrazine on the consumption of oxygen by hydrazine. The test results revealed that dissolved oxygen measurements in CANDU plants are underestimated to various degrees, depending on the sampling system operating conditions. Two distinct types of behaviours are observed for the oxygen removal rate: 1) the percentage removal of dissolved oxygen is invariant with time during the tests, and increases with increasing residence time in the test section, when the reaction between hydrazine and oxygen is better described by a homogenous reaction mechanism, and 2) the percentage oxygen

A feasibility study of a PET/MRI insert detector using strip-line and waveform sampling data acquisition.

Science.gov (United States)

Kim, H; Chen, C-T; Eclov, N; Ronzhin, A; Murat, P; Ramberg, E; Los, S; Wyrwicz, Alice M; Li, Limin; Kao, C-M

2015-06-01

We are developing a time-of-flight Positron Emission Tomography (PET) detector by using silicon photo-multipliers (SiPM) on a strip-line and high speed waveform sampling data acquisition. In this design, multiple SiPMs are connected on a single strip-line and signal waveforms on the strip-line are sampled at two ends of the strip to reduce readout channels while fully exploiting the fast time response of SiPMs. In addition to the deposited energy and time information, the position of the hit SiPM along the strip-line is determined by the arrival time difference of the waveform. Due to the insensitivity of the SiPMs to magnetic fields and the compact front-end electronics, the detector approach is highly attractive for developing a PET insert system for a magnetic resonance imaging (MRI) scanner to provide simultaneous PET/MR imaging. To investigate the feasibility, experimental tests using prototype detector modules have been conducted inside a 9.4 Tesla small animal MRI scanner (Bruker BioSpec 94/30 imaging spectrometer). On the prototype strip-line board, 16 SiPMs (5.2 mm pitch) are installed on two strip-lines and coupled to 2 × 8 LYSO scintillators (5.0 × 5.0 × 10.0 mm 3 with 5.2 mm pitch). The outputs of the strip-line boards are connected to a Domino-Ring-Sampler (DRS4) evaluation board for waveform sampling. Preliminary experimental results show that the effect of interference on the MRI image due to the PET detector is negligible and that PET detector performance is comparable with the results measured outside the MRI scanner.

Suitability of the line intersect method for sampling hardwood logging residues

Science.gov (United States)

A. Jeff Martin

1976-01-01

The line intersect method of sampling logging residues was tested in Appalachian hardwoods and was found to provide unbiased estimates of the volume of residue in cubic feet per acre. Thirty-two chains of sample line were established on each of sixteen 1-acre plots on cutover areas in a variety of conditions. Estimates from these samples were then compared to actual...

Electron spin resonance of particulate soot samples from automobiles to help environmental studies

International Nuclear Information System (INIS)

Yamanaka, C.; Matsuda, T.; Ikeya, M.

2005-01-01

The application of electron spin resonance (ESR) was studied for diesel soot samples and suspended particulate matter (SPM) from automobile engines. Soot samples or diesel exhaust particles (DEP) were recovered at various points: in the exhaust pipe of a diesel engine, at the dust sampler of a highway tunnel (standard DEP), on the soundproofing wall alongside a heavy traffic road, and on the filters of a dust sampler for SPM. The diesel soot samples apparently showed two ESR spectra: one was a broad spectrum at g=2.1 with a line width of ca. 80-120mT and the other was a sharp signal of a carbon radical at g=2.003 with a line width of 0.4mT. Annealing experiments with a DEP sample at 250 deg. C revealed drastic enhancement of the sharp ESR signal, which suggested a thermal process of carbonization of remnant organics. An oximetric study by ESR showed an enhancement of the broad signal in the diesel soot sample as well as in the sharp ESR signal. Therefore, the main part of the broad ESR signal would be attributed to carbon radicals, which form a different configuration, probably closely interacting aggregates. Enhancement of the sharp ESR signal was not observed in the standard DEP sample under vacuum condition, which suggested less adsorption sites on the surface of DEP samples

Status of the proton and electron transfer lines for the AWAKE Experiment at CERN

Energy Technology Data Exchange (ETDEWEB)

Schmidt, J.S., E-mail: janet.schmidt@cern.ch [CERN, Geneva (Switzerland); Bauche, J. [CERN, Geneva (Switzerland); Biskup, B. [CERN, Geneva (Switzerland); Czech Technical University, Prague (Czech Republic); Bracco, C.; Doebert, S.; Goddard, B.; Gschwendtner, E.; Jensen, L.K.; Jones, O.R.; Mazzoni, S.; Meddahi, M.; Pepitone, K.; Petrenko, A.; Velotti, F.M.; Vorozhtsov, A. [CERN, Geneva (Switzerland)

2016-09-01

The AWAKE project at CERN is planned to study proton driven plasma wakefield acceleration with an externally injected electron beam. Therefore two transfer lines are being designed in order to provide the proton beam from the SPS and the electron beam from an RF gun to the plasma cell. The commissioning of the proton line will take place in 2016 for the first phase of the experiment, which is focused on the self-modulation of a 12 cm long proton bunch in the plasma. The electron line will be added for the second phase of AWAKE in 2017, when the wakefield will be probed with an electron beam of 10–20 MeV/c. The challenge for these transfer lines lies in the parallel operation of the proton, electron and laser beam used to ionize the plasma and seed the self-modulation. These beams, of different characteristics, need to be synchronized and positioned for optimized injection conditions into the wakefield. This task requires great flexibility in the transfer line optics. The status of these designs will be presented in this paper.

Sample handling and transport for the Secure Automated Fabrication line

International Nuclear Information System (INIS)

Sherrell, D.L.; Jensen, J.D.; Genoway, G.G.; Togesen, H.J.

1983-06-01

A totally automated system is described which packages, transports, receives, and unpackages sintered plutonium/uranium oxide fuel pellet samples to support automated chemical analysis equipment for the Secure Automated Fabrication (SAF) line. Samples are transferred 100 meters from the fuel production line to a different floor of the facility where automatic determinations are made for purposes of process control and fuel quality certification. The system automatically records identification numbers, net weights sent and received, and all other pertinent information such as fuel lot number, sample point, date, and time of day

Multistage linear electron acceleration using pulsed transmission lines

International Nuclear Information System (INIS)

Miller, R.B.; Prestwich, K.R.; Poukey, J.W.; Epstein, B.G.; Freeman, J.R.; Sharpe, A.W.; Tucker, W.K.; Shope, S.L.

1981-01-01

A four-stage linear electron accelerator is described which uses pulsed radial transmission lines as the basic accelerating units. An annular electron beam produced by a foilless diode is guided through the accelerator by a strong axial magnetic field. Synchronous firing of the injector and the acccelerating modules is accomplished with self-breaking oil switches. The device has accelerated beam currents of 25 kA to kinetic energies of 9 MV, with 90% current transport efficiency. The average accelerating gradient is 3 MV/m

A line-of-sight electron cyclotron emission receiver for electron cyclotron resonance heating feedback control of tearing modes

DEFF Research Database (Denmark)

Oosterbeek, J.W.; Bürger, A.; Westerhof, E.

2008-01-01

An electron cyclotron emission (ECE) receiver inside the electron cyclotron resonance heating (ECRH) transmission line has been brought into operation. The ECE is extracted by placing a quartz plate acting as a Fabry-Perot interferometer under an angle inside the electron cyclotron wave (ECW) bea...

Resistively detected NMR line shapes in a quasi-one-dimensional electron system

Science.gov (United States)

Fauzi, M. H.; Singha, A.; Sahdan, M. F.; Takahashi, M.; Sato, K.; Nagase, K.; Muralidharan, B.; Hirayama, Y.

2017-06-01

We observe variation in the resistively detected nuclear magnetic resonance (RDNMR) line shapes in quantum Hall breakdown. The breakdown occurs locally in a gate-defined quantum point contact (QPC) region. Of particular interest is the observation of a dispersive line shape occurring when the bulk two-dimensional electron gas (2DEG) set to νb=2 and the QPC filling factor to the vicinity of νQPC=1 , strikingly resemble the dispersive line shape observed on a 2D quantum Hall state. This previously unobserved line shape in a QPC points to a simultaneous occurrence of two hyperfine-mediated spin flip-flop processes within the QPC. Those events give rise to two different sets of nuclei polarized in the opposite direction and positioned at a separate region with different degrees of electronic spin polarization.

Optimum field size and choice of isodose lines in electron beam treatment

International Nuclear Information System (INIS)

Das, Indra J.; Cheng, Chee W.; Healey, Glenn A.

1995-01-01

Purpose: A method is provided for the optimum field size and the choice of isodose line for the dose prescription in electron beam therapy. Methods and Materials: Electron beam dose uniformity was defined in terms of target coverage factor (TCF) which is an index of dose coverage of a given treatment volume. The TCF was studied with respect to the field size, the beam energy, and the isodose level for prescription from the measured data for various accelerators. The effect of the TCF on air gap between electron applicator/cone and the surface was investigated. Electron beams from scattering foil and scanned beam units were analyzed for the target coverage. Results: A mathematical method is provided to optimize a field size for target coverage by a given isodose line in terms of TCF which is strongly dependent on the type of accelerator and the design of the collimator. For a given type of collimating system, the TCF does not depend on the type of electron beam production (scattering foil or swept scanned beam). Selection of isodose line for dose prescription is very critical for the value of the TCF and the dose coverage. The TCF is inversely proportional to the isodose value selected for the treatment and nearly linear with field size and beam energy. Air gap between applicator and the surface reduces the dose uniformity. Tertiary collimator moderately improves the lateral coverage for high energy beams. Conclusions: To adequately cover the target volume in electron beam treatment, lateral and depth coverage should be considered. The coverage at depth is strongly dependent on the choice of isodose line or beam normalization. If the dose prescription is at d max (i.e., the 100% isodose line is selected), the choice of beam energy is not critical for depth coverage since d max is nearly independent of energy for smaller fields. The 100% isodose line should not be chosen for treatment because of the significant constriction of this isodose line and inadequate

Enhancement of the incoherent scattering plasma lines due to precipitating protons and secondary electrons

International Nuclear Information System (INIS)

Bjoernaa, N.; Havnes, O.; Jensen, J.O.; Trulsen, J.

1982-01-01

Precipitating protons in the energy range 1-100 keV are regularly present in the auroral ionosphere. These protons will produce enhancements in the intensity of the upshifted plasma line of the incoherently scattered spectrum. Similarly, secondary electrons produced by the precipitating protons give rise to enhanced plasma line intensities. For a quantitative discussion of these effects an experimentally measured proton flux is adapted and the corresponding secondary electron flux calculated. These particle fluxes are then applied in connection with the EISCAT radar facility. Both fluxes give rise to enhancements of the order of 20. It is possible to separate between proton and electron contributions to the enhanced plasma lines for scattering heights above the source region of secondary electrons. (Auth.)

Electron temperature determination from the HeI 3889 angstroem and 5016 angstroem line intensities

International Nuclear Information System (INIS)

Brenning, N.

1979-03-01

The possibility of determining electron temperature by helium spectro scopy in low-density (n(sub e) 2 m - ) plasmas is discussed. It is concluded that most lines can only be used at very low densities (n(sub e) 1 m - ) because the line intensities are highly influenced by secondary processes, such as electron impact induced transitions between excited levels or excitations from metastable levels. The density range where measurements are possible can extended if the influence of these secondary processes on the line intensities can be determined. For most helium I lines this is impossible for lack of atomic data. However, there are two exceptions, the 3889 angstroem (3 3 P yields 2 3 S) and the 5016 angstroem (3 1 yields 2 1 S) lines. The influence from secondary processes on these lines is calculated, and methods are developed which can be used for measurement of electron temperatures T(sub e 1 m - . The use of the methods is illustrated by a experiment where they have been successfully applied. (author)

Evaluating hepatocellular carcinoma cell lines for tumour samples using within-sample relative expression orderings of genes.

Science.gov (United States)

Ao, Lu; Guo, You; Song, Xuekun; Guan, Qingzhou; Zheng, Weicheng; Zhang, Jiahui; Huang, Haiyan; Zou, Yi; Guo, Zheng; Wang, Xianlong

2017-11-01

Concerns are raised about the representativeness of cell lines for tumours due to the culture environment and misidentification. Liver is a major metastatic destination of many cancers, which might further confuse the origin of hepatocellular carcinoma cell lines. Therefore, it is of crucial importance to understand how well they can represent hepatocellular carcinoma. The HCC-specific gene pairs with highly stable relative expression orderings in more than 99% of hepatocellular carcinoma but with reversed relative expression orderings in at least 99% of one of the six types of cancer, colorectal carcinoma, breast carcinoma, non-small-cell lung cancer, gastric carcinoma, pancreatic carcinoma and ovarian carcinoma, were identified. With the simple majority rule, the HCC-specific relative expression orderings from comparisons with colorectal carcinoma and breast carcinoma could exactly discriminate primary hepatocellular carcinoma samples from both primary colorectal carcinoma and breast carcinoma samples. Especially, they correctly classified more than 90% of liver metastatic samples from colorectal carcinoma and breast carcinoma to their original tumours. Finally, using these HCC-specific relative expression orderings from comparisons with six cancer types, we identified eight of 24 hepatocellular carcinoma cell lines in the Cancer Cell Line Encyclopedia (Huh-7, Huh-1, HepG2, Hep3B, JHH-5, JHH-7, C3A and Alexander cells) that are highly representative of hepatocellular carcinoma. Evaluated with a REOs-based prognostic signature for hepatocellular carcinoma, all these eight cell lines showed the same metastatic properties of the high-risk metastatic hepatocellular carcinoma tissues. Caution should be taken for using hepatocellular carcinoma cell lines. Our results should be helpful to select proper hepatocellular carcinoma cell lines for biological experiments. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Off-line electronic cash based on secret-key certificates

NARCIS (Netherlands)

S.A. Brands (Stefan)

1995-01-01

textabstractAn off-line electronic coin system is presented that offers multi-party security and unconditional privacy of payments. The system improves significantly on the efficiency of the previously most efficient such system known in the literature, due to application of a recently proposed

Deterministic Line-Shape Programming of Silicon Nanowires for Extremely Stretchable Springs and Electronics.

Science.gov (United States)

Xue, Zhaoguo; Sun, Mei; Dong, Taige; Tang, Zhiqiang; Zhao, Yaolong; Wang, Junzhuan; Wei, Xianlong; Yu, Linwei; Chen, Qing; Xu, Jun; Shi, Yi; Chen, Kunji; Roca I Cabarrocas, Pere

2017-12-13

Line-shape engineering is a key strategy to endow extra stretchability to 1D silicon nanowires (SiNWs) grown with self-assembly processes. We here demonstrate a deterministic line-shape programming of in-plane SiNWs into extremely stretchable springs or arbitrary 2D patterns with the aid of indium droplets that absorb amorphous Si precursor thin film to produce ultralong c-Si NWs along programmed step edges. A reliable and faithful single run growth of c-SiNWs over turning tracks with different local curvatures has been established, while high resolution transmission electron microscopy analysis reveals a high quality monolike crystallinity in the line-shaped engineered SiNW springs. Excitingly, in situ scanning electron microscopy stretching and current-voltage characterizations also demonstrate a superelastic and robust electric transport carried by the SiNW springs even under large stretching of more than 200%. We suggest that this highly reliable line-shape programming approach holds a strong promise to extend the mature c-Si technology into the development of a new generation of high performance biofriendly and stretchable electronics.

Tailoring of electron flow current in magnetically insulated transmission lines

Directory of Open Access Journals (Sweden)

J. P. Martin

2009-03-01

Full Text Available It is desirable to optimize (minimizing both the inductance and electron flow the magnetically insulated vacuum sections of low impedance pulsed-power drivers. The goal of low inductance is understandable from basic efficiency arguments. The goal of low electron flow results from two observations: (1 flowing electrons generally do not deliver energy to (or even reach most loads, and thus constitute a loss mechanism; (2 energetic electrons deposited in a small area can cause anode damage and anode plasma formation. Low inductance and low electron flow are competing goals; an optimized system requires a balance of the two. While magnetically insulated systems are generally forgiving, there are times when optimization is crucial. For example, in large pulsed-power drivers used to energize high energy density physics loads, the electron flow as a fraction of total current is small, but that flow often reaches the anode in relatively small regions. If the anode temperature becomes high enough to desorb gas, the resulting plasma initiates a gap closure process that can impact system performance. Magnetic-pressure driven (z pinches and material equation of state loads behave like a fixed inductor for much of the drive pulse. It is clear that neither fixed gap nor constant-impedance transmission lines are optimal for driving inductive loads. This work shows a technique for developing the optimal impedance profile for the magnetically insulated section of a high-current driver. Particle-in-cell calculations are used to validate the impedance profiles developed in a radial disk magnetically insulated transmission line geometry. The input parameters are the spacing and location of the minimum gap, the effective load inductance, and the desired electron flow profile. The radial electron flow profiles from these simulations are in good agreement with theoretical predictions when driven at relatively high voltage (i.e., V≥2  MV.

Correlation function and electronic spectral line broadening in relativistic plasmas

Directory of Open Access Journals (Sweden)

Douis S.

2013-01-01

Full Text Available The electrons dynamics and the time autocorrelation function Cee(t for the total electric microfield of the electrons on positive charge impurity embedded in a plasma are considered when the relativistic dynamic of the electrons is taken into account. We have, at first, built the effective potential governing the electrons dynamics. This potential obeys a nonlinear integral equation that we have solved numerically. Regarding the electron broadening of the line in plasma, we have found that when the plasma parameters change, the amplitude of the collision operator changes in the same way as the time integral of Cee(t. The electron-impurity interaction is taken at first time as screened Deutsh interaction and at the second time as Kelbg interaction. Comparisons of all interesting quantities are made with respect to the previous interactions as well as between classical and relativistic dynamics of electrons.

Design and development of line type modulators for high impedance electron gun

Energy Technology Data Exchange (ETDEWEB)

Dixit, Kavita P.; Tillu, Abhijit; Chavan, Ramchandra; Yadav, Vivek; Sarukte, Hemant, E-mail: kavidi@barc.gov.in [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Mumbai (India)

2014-07-01

Conventional line type modulators are routinely used for powering pulsed power microwave devices such as magnetrons and klystrons used for radar, medical and scientific applications. The load impedance (operating point) is fairly well defined in these cases, and makes the design of the discharging circuit of the modulator straight forward. This paper describes the Line type modulators that have been developed and being routinely used for powering the Triode Electron Gun of industrial electron linacs. The beam parameters of such guns are user defined and the pulse current varies from few mA to 800mA (typ). The beam energies requirement varies from 40 keV to 80 keV. Hence the impedance offered by the electron gun to the power source (modulator) is not well defined. The load capacitance which is inclusive of the various stray capacitances along with the intrinsic gun capacitance is ∼ 200-400 pF. This capacitance, which depends on the configuration, shunts the load and makes the effective load highly capacitive with the resistive part varying over a wide range. The paper describes the design and development of conventional line type modulators for powering Electron gun load of the type described above. (author)

MMS Observations of Electron-Scale Filamentary Currents in the Reconnection Exhaust and Near the X Line

Science.gov (United States)

Phan, T. D.; Eastwood, J. P.; Cassak, P. A.; Oieroset, M.; Gosling, J. T.; Gershman, D. J.; Mozer, F. S.; Shay, M. A.; Fujimoto, M.; Daughton, W.;

Electron temperature measurements by the plasma line technique at the French incoherent scatter radar facilities

International Nuclear Information System (INIS)

Kofman, W.; Lejeune, G.; Hagfors, T.; Bauer, P.

1981-01-01

The results of experiments aimed at the determination of the electron temperature by a plasma line technique are presented. Using the multistatic capabilities of the French incoherent scatter radar, the plasma line frequencies were simultaneously measured at two receiving stations (Mende and Nancay) at the altitude corresponding to the maximum of the F layer. Different plasma line frequencies are measued because of different effective k vectors that appear in the thermal term of the plasma dispersion relation. We derive and apply two data analysis procedures that enable us to determine this frequency difference. Comparison of this measured frequency difference to that calculated using the ion component electron temperature demonstrates that the plasma lines could indeed be used to determine the electron temperature. A strong dependence of the power in the plasma line as a function of the angle between k vector and magnetic field is observed in agreement with the theory. The future developments of this technique with the EISCAT radar facilities are discussed

Design unbiased estimation in line intersect sampling using segmented transects

Science.gov (United States)

David L.R. Affleck; Timothy G. Gregoire; Harry T. Valentine; Harry T. Valentine

2005-01-01

In many applications of line intersect sampling. transects consist of multiple, connected segments in a prescribed configuration. The relationship between the transect configuration and the selection probability of a population element is illustrated and a consistent sampling protocol, applicable to populations composed of arbitrarily shaped elements, is proposed. It...

Electron density in the emission-line region of Wolf-Rayet stars

International Nuclear Information System (INIS)

Varshni, Y.P.

1978-01-01

The Inglis-Teller relation, generalized for a hydrogen-like or alkali-like ion with an arbitrary core charge, is used to estimate the electron density in the emission-like region of Wolf-Rayet stars. It is found that the electron density in the region which gives rise to He II emission lines is approximately = 4 x 10 14 cm -3 . (Auth.)

Beam line design for a low energy electron beam

International Nuclear Information System (INIS)

Arvind Kumar; Mahadevan, S.

2002-01-01

The design of a beam line for transport of a 70 keV electron beam from a thermionic gun to the Plane Wave Transformer (PWT) linac incorporating two solenoid magnets, a beam profile monitor and drift sections is presented. We used beam dynamics codes EGUN, PARMELA and compare simulated results with analytical calculations. (author)

Note: Characteristic beam parameter for the line electron gun

Science.gov (United States)

Iqbal, M.; Islam, G. U.; Zhou, Z.; Chi, Y.

2013-11-01

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm2 at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm2), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

Note: Characteristic beam parameter for the line electron gun

International Nuclear Information System (INIS)

Iqbal, M.; Islam, G. U.; Zhou, Z.; Chi, Y.

2013-01-01

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm 2 at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm 2 ), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful

Note: Characteristic beam parameter for the line electron gun.

Science.gov (United States)

Iqbal, M; Islam, G U; Zhou, Z; Chi, Y

2013-11-01

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm(2) at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm(2)), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

Sparse sampling and reconstruction for electron and scanning probe microscope imaging

Science.gov (United States)

Anderson, Hyrum; Helms, Jovana; Wheeler, Jason W.; Larson, Kurt W.; Rohrer, Brandon R.

2015-07-28

Systems and methods for conducting electron or scanning probe microscopy are provided herein. In a general embodiment, the systems and methods for conducting electron or scanning probe microscopy with an undersampled data set include: driving an electron beam or probe to scan across a sample and visit a subset of pixel locations of the sample that are randomly or pseudo-randomly designated; determining actual pixel locations on the sample that are visited by the electron beam or probe; and processing data collected by detectors from the visits of the electron beam or probe at the actual pixel locations and recovering a reconstructed image of the sample.

Magnetically insulated transmission line used for relativistic electron beam injection into SPAC-VI

International Nuclear Information System (INIS)

Tsuzuki, Tetsuya; Narihara, Kazumichi; Tomita, Yukihiro; Mohri, Akihiro.

1980-10-01

For the purpose to inject the electron beam with energy of about 1.5 MeV and current of about 100 kA into the SPAC-6 (torus device), a magnetically insulated transmission line was designed and constructed. The motion of electrons in the line was theoretically analyzed. The requirements for the design of the transmission line were as follows-: (a) condition of magnetic insulation, (b) suppression against reverse gas flow from the beam source to the torus, (c) care to minimize the influence of strong torus magnetic field, (d) reduction of inductance and (e) safety engineering measures, e.g., separation valve in the MITL between the beam source and the SPAC-6. The transmission line of 2.4 m long was designed and constructed. The wave forms of electric potential and current were measured. The transmission efficiency of current along the axis and the efficiency as a function of current at the end of the line were also measured. The reason of the loss of current is discussed. (J.P.N.)

Sample Preparation for Electron Probe Microanalysis-Pushing the Limits.

Science.gov (United States)

Geller, Joseph D; Engle, Paul D

2002-01-01

There are two fundamental considerations in preparing samples for electron probe microanalysis (EPMA). The first one may seem obvious, but we often find it is overlooked. That is, the sample analyzed should be representative of the population from which it comes. The second is a direct result of the assumptions in the calculations used to convert x-ray intensity ratios, between the sample and standard, to concentrations. Samples originate from a wide range of sources. During their journey to being excited under the electron beam for the production of x rays there are many possibilities for sample alteration. Handling can contaminate samples by adding extraneous matter. In preparation, the various abrasives used in sizing the sample by sawing, grinding and polishing can embed themselves. The most accurate composition of a contaminated sample is, at best, not representative of the original sample; it is misleading. Our laboratory performs EPMA analysis on customer submitted samples and prepares over 250 different calibration standards including pure elements, compounds, alloys, glasses and minerals. This large variety of samples does not lend itself to mass production techniques, including automatic polishing. Our manual preparation techniques are designed individually for each sample. The use of automated preparation equipment does not lend itself to this environment, and is not included in this manuscript. The final step in quantitative electron probe microanalysis is the conversion of x-ray intensities ratios, known as the "k-ratios," to composition (in mass fraction or atomic percent) and/or film thickness. Of the many assumptions made in the ZAF (where these letters stand for atomic number, absorption and fluorescence) corrections the localized geometry between the sample and electron beam, or takeoff angle, must be accurately known. Small angular errors can lead to significant errors in the final results. The sample preparation technique then becomes very

Tunable valley polarization by a gate voltage when an electron tunnels through multiple line defects in graphene.

Science.gov (United States)

Liu, Zhe; Jiang, Liwei; Zheng, Yisong

2015-02-04

By means of an appropriate wave function connection condition, we study the electronic structure of a line defect superlattice of graphene with the Dirac equation method. We obtain the analytical dispersion relation, which can simulate well the tight-binding numerical result about the band structure of the superlattice. Then, we generalize this theoretical method to study the electronic transmission through a potential barrier where multiple line defects are periodically patterned. We find that there exists a critical incident angle which restricts the electronic transmission through multiple line defects within a specific incident angle range. The critical angle depends sensitively on the potential barrier height, which can be modulated by a gate voltage. As a result, non-trivial transmissions of K and K' valley electrons are restricted, respectively, in two distinct ranges of the incident angle. Our theoretical result demonstrates that a gate voltage can act as a feasible measure to tune the valley polarization when electrons tunnel through multiple line defects.

Note: Characteristic beam parameter for the line electron gun

Energy Technology Data Exchange (ETDEWEB)

Iqbal, M. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Islam, G. U. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Zhou, Z.; Chi, Y. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

2013-11-15

We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm{sup 2} at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm{sup 2}), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

Electron temperature measurement by a helium line intensity ratio method in helicon plasmas

International Nuclear Information System (INIS)

Boivin, R.F.; Kline, J.L.; Scime, E.E.

2001-01-01

Electron temperature measurements in helicon plasmas are difficult. The presence of intense rf fields in the plasma complicates the interpretation of Langmuir probe measurements. Furthermore, the non-negligible ion temperature in the plasma considerably shortens the lifetime of conventional Langmuir probes. A spectroscopic technique based on the relative intensities of neutral helium lines is used to measure the electron temperature in the HELIX (Hot hELicon eXperiment) plasma [P. A. Keiter et al., Phys. Plasmas 4, 2741 (1997)]. This nonintrusive diagnostic is based on the fact that electron impact excitation rate coefficients for helium singlet and triplet states differ as a function of the electron temperature. The different aspects related to the validity of this technique to measure the electron temperature in rf generated plasmas are discussed in this paper. At low plasma density (n e ≤10 11 cm -3 ), this diagnostic is believed to be very reliable since the population of the emitting level can be easily estimated with reasonable accuracy by assuming that all excitation originates from the ground state (steady-state corona model). At higher density, secondary processes (excitation transfer, excitation from metastable, cascading) become more important and a more complex collisional radiative model must be used to predict the electron temperature. In this work, different helium transitions are examined and a suitable transition pair is identified. For an electron temperature of 10 eV, the line ratio is measured as a function of plasma density and compared to values predicted by models. The measured line ratio function is in good agreement with theory and the data suggest that the excitation transfer is the dominant secondary process in high-density plasmas

GET electronics samples data analysis

International Nuclear Information System (INIS)

Giovinazzo, J.; Goigoux, T.; Anvar, S.; Baron, P.; Blank, B.; Delagnes, E.; Grinyer, G.F.; Pancin, J.; Pedroza, J.L.; Pibernat, J.; Pollacco, E.; Rebii, A.

2016-01-01

The General Electronics for TPCs (GET) has been developed to equip a generation of time projection chamber detectors for nuclear physics, and may also be used for a wider range of detector types. The goal of this paper is to propose first analysis procedures to be applied on raw data samples from the GET system, in order to correct for systematic effects observed on test measurements. We also present a method to estimate the response function of the GET system channels. The response function is required in analysis where the input signal needs to be reconstructed, in terms of time distribution, from the registered output samples.

Electronic and magnetic properties of MoS2 nanoribbons with sulfur line vacancy defects

International Nuclear Information System (INIS)

Han, Yang; Zhou, Jian; Dong, Jinming

2015-01-01

Highlights: • We performed DFT calculations on Sulfur line defects embedded MoS 2 . • The defects induced bond strains are larger in the zigzag (ZZ) edge ones. • The ZZ ones are metals, having two degenerate ground states FM and AFM. • The armchair ones are nonmagnetic semiconductors. • The defects can induce some defect states in the electronic structures. - Abstract: Motivated by the recent experimental result that single sulfur vacancies in monolayer MoS 2 are mobile under the electron beam and easily agglomerate into the sulfur line vacancy defects [Physical Review B 88, 035301(2013)] , the structural, electronic and magnetic properties of one dimensional zigzag (ZZ) and armchair (AC) edge MoS 2 nanoribbons with single or double staggered sulfur line vacancy defects (hereafter, abbreviated as SV or DV, respectively), parallel to their edges, have been investigated systematically by density functional theory calculations. It is very interesting to find that the bond strains induced by the sulfur line vacancy defect can cause a much larger out-of plane distortions in the ZZ edge MoS 2 nanoribbon than in the AC edge counterpart. Besides, the defective ZZ edge MoS 2 nanoribbons with SV or DV are both metals, having their two respective degenerate ground states with the same energy, among which one is ferromagnetic (FM “ + +”) and the other is antiferromagnetic (AFM “ + −”). But the AC edge MoS 2 nanoribbons with SV or DV are both nonmagnetic semiconductors, having very different gap values. Finally, the sulfur line vacancy defects would induce some defect states in the electronic structures of the defective MoS 2 nanoribbons. All these important results could provide a new route of tuning the electronic properties of MoS 2 nanoribbons and its derivatives for their promising applications in nanoelectronics and optoelectronics

Coronal Magnetic Field Lines and Electrons Associated with Type III ...

Indian Academy of Sciences (India)

P. Kishore

2017-06-19

Jun 19, 2017 ... of the electron streams that generate type V bursts, spread in the velocity spectrum, and the curvature of the magnetic field lines along which they travel. Keywords. Sun—corona—magnetic field—flares—radio bursts—polarization. 1. Introduction. Type V bursts are relatively unusual solar radio tran- sients.

Sample Preparation for Electron Probe Microanalysis—Pushing the Limits

Science.gov (United States)

Geller, Joseph D.; Engle, Paul D.

2002-01-01

There are two fundamental considerations in preparing samples for electron probe microanalysis (EPMA). The first one may seem obvious, but we often find it is overlooked. That is, the sample analyzed should be representative of the population from which it comes. The second is a direct result of the assumptions in the calculations used to convert x-ray intensity ratios, between the sample and standard, to concentrations. Samples originate from a wide range of sources. During their journey to being excited under the electron beam for the production of x rays there are many possibilities for sample alteration. Handling can contaminate samples by adding extraneous matter. In preparation, the various abrasives used in sizing the sample by sawing, grinding and polishing can embed themselves. The most accurate composition of a contaminated sample is, at best, not representative of the original sample; it is misleading. Our laboratory performs EPMA analysis on customer submitted samples and prepares over 250 different calibration standards including pure elements, compounds, alloys, glasses and minerals. This large variety of samples does not lend itself to mass production techniques, including automatic polishing. Our manual preparation techniques are designed individually for each sample. The use of automated preparation equipment does not lend itself to this environment, and is not included in this manuscript. The final step in quantitative electron probe microanalysis is the conversion of x-ray intensities ratios, known as the “k-ratios,” to composition (in mass fraction or atomic percent) and/or film thickness. Of the many assumptions made in the ZAF (where these letters stand for atomic number, absorption and fluorescence) corrections the localized geometry between the sample and electron beam, or takeoff angle, must be accurately known. Small angular errors can lead to significant errors in the final results. The sample preparation technique then becomes very

Shielded scanning electron microscope for radioactive samples

International Nuclear Information System (INIS)

Crouse, R.S.; Parsley, W.B.

1977-01-01

A small commercial SEM had been successfully shielded for examining radioactive materials transferred directly from a remote handling facility. Relatively minor mechanical modifications were required to achieve excellent operation. Two inches of steel provide adequate shielding for most samples encountered. However, samples reading 75 rad/hr γ have been examined by adding extra shielding in the form of tungsten sample holders and external lead shadow shields. Some degradation of secondary electron imaging was seen but was adequately compensated for by changing operating conditions

A line-based vegetation sampling technique and its application in ...

African Journals Online (AJOL)

percentage cover, density and intercept frequency) and also provides plant size distributions, yet requires no more sampling effort than the line-intercept method.. A field test of the three techniques in succulent karoo, showed that the discriminating ...

Determination of line edge roughness in low-dose top-down scanning electron microscopy images

NARCIS (Netherlands)

Verduin, T.; Kruit, P.; Hagen, C.W.

2014-01-01

We investigated the off-line metrology for line edge roughness (LER) determination by using the discrete power spectral density (PSD). The study specifically addresses low-dose scanning electron microscopy (SEM) images in order to reduce the acquisition time and the risk of resist shrinkage. The

Counterstreaming solar wind halo electron events on open field lines?

Science.gov (United States)

Gosling, J. T.; Mccomas, D. J.; Phillips, J. L.

1992-01-01

Counterstreaming solar wind halo electron events have been identified as a common 1 AU signature of coronal mass ejection events, and have generally been interpreted as indicative of closed magnetic field topologies, i.e., magnetic loops or flux ropes rooted at both ends in the Sun, or detached plasmoids. In this paper we examine the possibility that these events may instead occur preferentially on open field lines, and that counterstreaming results from reflection or injection behind interplanetary shocks or from mirroring from regions of compressed magnetic field farther out in the heliosphere. We conclude that neither of these suggested sources of counterstreaming electron beams is viable and that the best interpretation of observed counterstreaming electron events in the solar wind remains that of passage of closed field structures.

Relativistic electron flux dropout due to field line curvature during the storm on 1 June 2013

Science.gov (United States)

Kang, S. B.; Fok, M. C. H.; Engebretson, M. J.; Li, W.; Glocer, A.

2017-12-01

Significant electron flux depletion over a wide range of L-shell and energy, referred as a dropout, was observed by Van Allen Probes during the storm main phase on June 1, 2013. During the same period, MeV electron precipitation with isotropic pitch-angle distribution was also observed in the evening sector from POES but no EMIC waves were detected from either space- or ground-based magnetometers. Based on Tsyganenko empirical magnetic field model, magnetic field lines are highly non-dipolar and stretched at the night side in the inner magnetosphere. This condition can break the first adiabatic invariant (conservation of magnetic moment) and generate pitch-angle scattering of relativistic electron to the loss cone. To understand the relative roles of different physical mechanisms on this dropout event, we simulate flux and phase space density of relativistic electrons with event specific plasma wave intensities using the Comprehensive Inner Magnetosphere and Ionosphere (CIMI) model, as a global 4-D inner magnetosphere model. We also employ pitch-angle scattering due to field line curvature in the CIMI model. We re-configure magnetic field every minute and update electric field every 20 seconds to capture radial transport. CIMI-simulation with pitch-angle scattering due to field line curvature shows more depletion of relativistic electron fluxes and better agreement to observation than CIMI-simulation with radial transport only. We conclude that pitch-angle scattering due to field line curvature is one of the dominant processes for the relativistic electron flux dropout.

Electron-impact excitation collision strengths and theoretical line intensities for transitions in S III

Energy Technology Data Exchange (ETDEWEB)

Grieve, M. F. R.; Ramsbottom, C. A.; Hudson, C. E. [Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen' s University Belfast, Belfast, BT7 1NN (United Kingdom); Keenan, F. P., E-mail: c.ramsbottom@qub.ac.uk [Astrophysics Research Centre, School of Mathematics and Physics, Queen' s University Belfast, Belfast, BT7 1NN (United Kingdom)

2014-01-01

We present Maxwellian-averaged effective collision strengths for the electron-impact excitation of S III over a wide range of electron temperatures of astrophysical importance, log T{sub e} (K) = 3.0-6.0. The calculation incorporates 53 fine-structure levels arising from the six configurations—3s {sup 2}3p {sup 2}, 3s3p {sup 3}, 3s {sup 2}3p3d, 3s {sup 2}3p4s, 3s {sup 2}3p4p, and 3s {sup 2}3p4d—giving rise to 1378 individual lines and is undertaken using the recently developed RMATRX II plus FINE95 suite of codes. A detailed comparison is made with a previous R-matrix calculation and significant differences are found for some transitions. The atomic data are subsequently incorporated into the modeling code CLOUDY to generate line intensities for a range of plasma parameters, with emphasis on allowed ultraviolet extreme-ultraviolet emission lines detected from the Io plasma torus. Electron density-sensitive line ratios are calculated with the present atomic data and compared with those from CHIANTI v7.1, as well as with Io plasma torus spectra obtained by Far-Ultraviolet Spectroscopic Explorer and Extreme-Ultraviolet Explorer. The present line intensities are found to agree well with the observational results and provide a noticeable improvement on the values predicted by CHIANTI.

Electronic and magnetic properties of MoS{sub 2} nanoribbons with sulfur line vacancy defects

Energy Technology Data Exchange (ETDEWEB)

Han, Yang [Group of Computational Condensed Matter Physics, National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Zhou, Jian [National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, Nanjing University, Nanjing 210093 (China); Dong, Jinming, E-mail: jdong@nju.edu.cn [Group of Computational Condensed Matter Physics, National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China)

2015-08-15

Highlights: • We performed DFT calculations on Sulfur line defects embedded MoS{sub 2}. • The defects induced bond strains are larger in the zigzag (ZZ) edge ones. • The ZZ ones are metals, having two degenerate ground states FM and AFM. • The armchair ones are nonmagnetic semiconductors. • The defects can induce some defect states in the electronic structures. - Abstract: Motivated by the recent experimental result that single sulfur vacancies in monolayer MoS{sub 2} are mobile under the electron beam and easily agglomerate into the sulfur line vacancy defects [Physical Review B 88, 035301(2013)] , the structural, electronic and magnetic properties of one dimensional zigzag (ZZ) and armchair (AC) edge MoS{sub 2} nanoribbons with single or double staggered sulfur line vacancy defects (hereafter, abbreviated as SV or DV, respectively), parallel to their edges, have been investigated systematically by density functional theory calculations. It is very interesting to find that the bond strains induced by the sulfur line vacancy defect can cause a much larger out-of plane distortions in the ZZ edge MoS{sub 2} nanoribbon than in the AC edge counterpart. Besides, the defective ZZ edge MoS{sub 2} nanoribbons with SV or DV are both metals, having their two respective degenerate ground states with the same energy, among which one is ferromagnetic (FM “ + +”) and the other is antiferromagnetic (AFM “ + −”). But the AC edge MoS{sub 2} nanoribbons with SV or DV are both nonmagnetic semiconductors, having very different gap values. Finally, the sulfur line vacancy defects would induce some defect states in the electronic structures of the defective MoS{sub 2} nanoribbons. All these important results could provide a new route of tuning the electronic properties of MoS{sub 2} nanoribbons and its derivatives for their promising applications in nanoelectronics and optoelectronics.

Theoretical interpretation of upstreaming electrons and elevated conics on auroral field lines

International Nuclear Information System (INIS)

Ashour-Abdalla, M.; Schriver, D.

1989-01-01

Recent VIKING satellite observations in the auroral zone have shown the association of elevated ion conics (conics with a low energy cutoff above zero) with upward streaming electrons in the presence of low frequency electric field fluctuations. A self-consistent particle simulation was developed which assumed the presence of a steady state electric field on auroral zone field lines capable of accelerating ions up the magnetic field lines. Results from this study show that a low frequency ion-ion two stream instability can be excited. This low frequency instability creates a fluctuating electric field which heats the ions oblique to the magnetic field forming distributions similar to the elevated ion comics. The ion-ion waves also interact resonantly with electrons and accelerates them in the direction of the ion beam

Electron temperature in field reversed configurations and theta pinches with closed magnetic field lines

International Nuclear Information System (INIS)

Newton, A.A.

1986-01-01

Field-reversed configurations (FRC) and theta pinches with trapped reversed bias field are essentially the same magnetic confinement systems using closed magnetic field lines inside an open-ended magnetic flux tube. A simple model of joule heating and parallel electron thermal conduction along the open flux lines to an external heat sink gives the electron temperature as Tsub(e)(eV) approx.= 0.05 Bsup(2/3)(G)Lsup(1/3)(cm), where B is the magnetic field and L is the coil length. This model appears to agree with measurements from present FRC experiments and past theta-pinch experiments which cover a range of 40-900 eV. The energy balance in the model is dominated by (a) parallel electron thermal conduction along the open field lines which has a steep temperature dependence, Q is proportional to Tsub(e)sup(7/2), and (b) the assumed rapid perpendicular transport in the plasma bulk which, in experiments to date, may be due to the small number of ion gyroradii across the plasma. (author)

Multiobjective optimization design of an rf gun based electron diffraction beam line

Directory of Open Access Journals (Sweden)

Colwyn Gulliford

2017-03-01

Full Text Available Multiobjective genetic algorithm optimizations of a single-shot ultrafast electron diffraction beam line comprised of a 100  MV/m 1.6-cell normal conducting rf (NCRF gun, as well as a nine-cell 2π/3 bunching cavity placed between two solenoids, have been performed. These include optimization of the normalized transverse emittance as a function of bunch charge, as well as optimization of the transverse coherence length as a function of the rms bunch length of the beam at the sample location for a fixed charge of 10^{6} electrons. Analysis of the resulting solutions is discussed in terms of the relevant scaling laws, and a detailed description of one of the resulting solutions from the coherence length optimizations is given. For a charge of 10^{6} electrons and final beam sizes of σ_{x}≥25  μm and σ_{t}≈5  fs, we found a relative coherence length of L_{c,x}/σ_{x}≈0.07 using direct optimization of the coherence length. Additionally, based on optimizations of the emittance as a function of final bunch length, we estimate the relative coherence length for bunch lengths of 30 and 100 fs to be roughly 0.1 and 0.2  nm/μm, respectively. Finally, using the scaling of the optimal emittance with bunch charge, for a charge of 10^{5} electrons, we estimate relative coherence lengths of 0.3, 0.5, and 0.92  nm/μm for final bunch lengths of 5, 30 and 100 fs, respectively.

Transmission electron microscope sample holder with optical features

Science.gov (United States)

Milas, Mirko [Port Jefferson, NY; Zhu, Yimei [Stony Brook, NY; Rameau, Jonathan David [Coram, NY

2012-03-27

A sample holder for holding a sample to be observed for research purposes, particularly in a transmission electron microscope (TEM), generally includes an external alignment part for directing a light beam in a predetermined beam direction, a sample holder body in optical communication with the external alignment part and a sample support member disposed at a distal end of the sample holder body opposite the external alignment part for holding a sample to be analyzed. The sample holder body defines an internal conduit for the light beam and the sample support member includes a light beam positioner for directing the light beam between the sample holder body and the sample held by the sample support member.

Electron beam effects on the spectroscopy of satellite lines in aluminum X-pinch experiments

International Nuclear Information System (INIS)

Abdallah, J. Jr.; Csanak, G.; Clark, R.E.H.; Faenov, A.Ya.; Hammer, D.A.; Pikuz, S.A.; Romanova, P.N.; Shelkovenko, T.A.

1996-01-01

Aluminum wire X-pinch experiments performed at the Cornell University XP pulsed power generator and at the Lebedev Institute BIN generator show detailed high resolution spectra for satellite lines of Li-like, Be-like, B-like, and C-like ions. These lines, which correspond to transitions originating from autoionizing levels, are observed in the direction of the anode with respect to the bright X-pinch cross point. The intensities of these satellites are much smaller or absent in the direction of the cathode. Such transitions are caused by collisions of ions with energetic electrons (5-15 keV) which are created by the inductive voltage drop between the cross point and the anode. A collisional-radiative model was constructed using a non-Maxwellian electron energy distribution consisting of a thermal Maxwellian part plus a Gaussian part to represent the high energy electron beam. The shapes of the observed satellite structures are consistent with the calculated spectrum for electron temperatures between 30-100 eV, and beam densities of about 10 -7 times the plasma electron density. (author). 3 figs., 7 refs

Electron beam effects on the spectroscopy of satellite lines in aluminum X-pinch experiments

Energy Technology Data Exchange (ETDEWEB)

Abdallah, J Jr; Csanak, G; Clark, R E.H. [Los Alamos National Laboratory, NM (United States); Faenov, A Ya [VNIIFTRI, Mendeleevo (Russian Federation); Hammer, D A [Cornell Univ., Ithaca, NY (United States); Pikuz, S A; Romanova, P N; Shelkovenko, T A [P.N. Lebedev Physical Inst., Moscow (Russian Federation)

1997-12-31

Aluminum wire X-pinch experiments performed at the Cornell University XP pulsed power generator and at the Lebedev Institute BIN generator show detailed high resolution spectra for satellite lines of Li-like, Be-like, B-like, and C-like ions. These lines, which correspond to transitions originating from autoionizing levels, are observed in the direction of the anode with respect to the bright X-pinch cross point. The intensities of these satellites are much smaller or absent in the direction of the cathode. Such transitions are caused by collisions of ions with energetic electrons (5-15 keV) which are created by the inductive voltage drop between the cross point and the anode. A collisional-radiative model was constructed using a non-Maxwellian electron energy distribution consisting of a thermal Maxwellian part plus a Gaussian part to represent the high energy electron beam. The shapes of the observed satellite structures are consistent with the calculated spectrum for electron temperatures between 30-100 eV, and beam densities of about 10{sup -7} times the plasma electron density. (author). 3 figs., 7 refs.

Electron density profile measurements from hydrogen line intensity ratio method in Versatile Experimental Spherical Torus

Energy Technology Data Exchange (ETDEWEB)

Kim, YooSung; Shi, Yue-Jiang, E-mail: yjshi@snu.ac.kr; Yang, Jeong-hun; Kim, SeongCheol; Kim, Young-Gi; Dang, Jeong-Jeung; Yang, Seongmoo; Jo, Jungmin; Chung, Kyoung-Jae [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Oh, Soo-Ghee [Division of Energy Systems Research, Ajou University, Suwon 442-749 (Korea, Republic of); Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Center for Advanced Research in Fusion Reactor Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of)

2016-11-15

Electron density profiles of versatile experiment spherical torus plasmas are measured by using a hydrogen line intensity ratio method. A fast-frame visible camera with appropriate bandpass filters is used to detect images of Balmer line intensities. The unique optical system makes it possible to take images of H{sub α} and H{sub β} radiation simultaneously, with only one camera. The frame rate is 1000 fps and the spatial resolution of the system is about 0.5 cm. One-dimensional local emissivity profiles have been obtained from the toroidal line of sight with viewing dumps. An initial result for the electron density profile is presented and is in reasonable agreement with values measured by a triple Langmuir probe.

Simultaneous measurement of line electron density and Faraday rotation in the ISX-B tokamak

International Nuclear Information System (INIS)

Hutchinson, D.P.; Ma, C.H.; Staats, P.A.; Vander Sluis, K.L.

1981-01-01

A new diagnostic system utilizing a submillimetre-wave, phase-modulated polarimeter/interferometer has been used to simultaneously measure the time evolution of the line-averaged electron density and poloidal field-induced Faraday rotation in the ISX-B tokamak. The measurements, performed along four chords of the plasma column, have been correlated with poloidal field changes associated with a ramp in the Ohmic-heating current and by neutral-beam injection. These are the first simultaneous measurements of line electron density and Faraday rotation to be made along a chord of submillimetre laser beam in a tokamak plasma. (author)

On-ground detection of an electron-positron annihilation line from thunderclouds.

Science.gov (United States)

Umemoto, D; Tsuchiya, H; Enoto, T; Yamada, S; Yuasa, T; Kawaharada, M; Kitaguchi, T; Nakazawa, K; Kokubun, M; Kato, H; Okano, M; Tamagawa, T; Makishima, K

2016-02-01

Thunderclouds can produce bremsstrahlung gamma-ray emission, and sometimes even positrons. At 00:27:00 (UT) on 13 January 2012, an intense burst of gamma rays from a thundercloud was detected by the GROWTH experiment, located in Japan, facing the Sea of Japan. The event started with a sharp gamma-ray flash with a duration of gamma-ray emission lasting for ∼60 s. The spectrum of this prolonged emission reached ∼10 MeV, and contained a distinct line emission at 508±3(stat.)±5(sys.) keV, to be identified with an electron-positron annihilation line. The line was narrow within the instrumental energy resolution (∼80keV), and contained 520±50 photons which amounted to ∼10% of the total signal photons of 5340±190 detected over 0.1-10 MeV. As a result, the line equivalent width reached 280±40 keV, which implies a nontrivial result. The result suggests that a downward positron beam produced both the continuum and the line photons.

Compton scattering of photons from electrons in magnetically insulated transmission lines

International Nuclear Information System (INIS)

Brower, K.L.; VanDevender, J.P.

1979-01-01

Self-magnetically insulated transmission lines are used for power transport between the vacuum insulator and the diode in high current particle accelerators. Since the efficiency of the power transport depends on the details of the initial line geometry, i.e., the injector, the dependence of the electron canonical momentum distribution on the injector geometry should reveal the loss mechanism. We propose to study that dependence experimentally through a Compton scattering diagnostic. The spectrum of scattered light reveals the electron velocity distribution perpendicular to the direction of flow. The design of the diagnostic is in progress. Our preliminary analysis is based on the conservation of energy and canonical momentum for a single electron in the anti E and anti B fields determined from 2-D calculations. For the Mite accelerator with power flow along Z, the normalized canonical momentum, μ, is in the range - 0.7 < μ less than or equal to 0. For anti k/sub i/ parallel to circumflex Y, and anti k/sub s/ circumflex X, our analysis indicates that the scattered photons have 1.1 eV less than or equal to h nu/sub s/ < 5.6 eV for ruby laser scattering and can be detected with PM tubes

The electron transport problem sampling by Monte Carlo individual collision technique

International Nuclear Information System (INIS)

Androsenko, P.A.; Belousov, V.I.

2005-01-01

The problem of electron transport is of most interest in all fields of the modern science. To solve this problem the Monte Carlo sampling has to be used. The electron transport is characterized by a large number of individual interactions. To simulate electron transport the 'condensed history' technique may be used where a large number of collisions are grouped into a single step to be sampled randomly. Another kind of Monte Carlo sampling is the individual collision technique. In comparison with condensed history technique researcher has the incontestable advantages. For example one does not need to give parameters altered by condensed history technique like upper limit for electron energy, resolution, number of sub-steps etc. Also the condensed history technique may lose some very important tracks of electrons because of its limited nature by step parameters of particle movement and due to weakness of algorithms for example energy indexing algorithm. There are no these disadvantages in the individual collision technique. This report presents some sampling algorithms of new version BRAND code where above mentioned technique is used. All information on electrons was taken from Endf-6 files. They are the important part of BRAND. These files have not been processed but directly taken from electron information source. Four kinds of interaction like the elastic interaction, the Bremsstrahlung, the atomic excitation and the atomic electro-ionization were considered. In this report some results of sampling are presented after comparison with analogs. For example the endovascular radiotherapy problem (P2) of QUADOS2002 was presented in comparison with another techniques that are usually used. (authors)

Nonlocal electron kinetics and spectral line emission in the positive column of an argon glow discharge

International Nuclear Information System (INIS)

Golubovskii, Yu; Kalanov, D; Gorchakov, S; Uhrlandt, D

2015-01-01

Modern non-local electron kinetics theory predicts several interesting effects connected with spectral line emission from the positive column in the range of low and medium pressures and currents. Some theoretical works describe non-monotonic behavior of the radial profiles of line emission at intermediate pressures and currents between the validity ranges of the non-local and local approximation of the electron kinetics. Despite a great number of publications, there have been no systematic measurements attempting to confirm these theoretical predictions through experiments. In this work the radial profiles of the line emission from the positive column of an argon glow discharge have been measured with high spatial resolution and new effects caused by the narrowing and broadening of the spatial emission profiles with dependence on discharge conditions have been discovered. The effect of intensity maximum shift predicted by theory using a self-consistent model was not found in the experiment. The properties of the spectral line radiation are influenced by the peculiarities of the formation of the high-energy tail of the electron energy distribution function. An interpretation of the observed effects based on the non-local character of the electron kinetics in radially inhomogeneous fields is given. The obtained experimental data are compared with the results of calculations. (paper)

Fried-Yennie gauge recalculation of the electron line induced radiative-recoil corrections to muonium hyperfine splitting

International Nuclear Information System (INIS)

Brook, V.Yu.; Eides, M.I.; Karshenboim, S.G.; Shelyuto, V.A.

1989-01-01

A new analytic calculation of radiative-recoil corrections to muonium ground-state hyperfine splitting induced by electron line insertions is performed. The starting point of this calculation is presented by the Fried-Yennie gauge expression for the electron line factor. The final result confirms the one obtained previously from the apparently different expression in the Feynman gauge and removes the slight discrepancy which existed in the literature between the calculations in different gauges. (orig.)

Development of a SEM-based low-energy in-line electron holography microscope for individual particle imaging.

Science.gov (United States)

Adaniya, Hidehito; Cheung, Martin; Cassidy, Cathal; Yamashita, Masao; Shintake, Tsumoru

2018-05-01

A new SEM-based in-line electron holography microscope has been under development. The microscope utilizes conventional SEM and BF-STEM functionality to allow for rapid searching of the specimen of interest, seamless interchange between SEM, BF-STEM and holographic imaging modes, and makes use of coherent low-energy in-line electron holography to obtain low-dose, high-contrast images of light element materials. We report here an overview of the instrumentation and first experimental results on gold nano-particles and carbon nano-fibers for system performance tests. Reconstructed images obtained from the holographic imaging mode of the new microscope show substantial image contrast and resolution compared to those acquired by SEM and BF-STEM modes, demonstrating the feasibility of high-contrast imaging via low-energy in-line electron holography. The prospect of utilizing the new microscope to image purified biological specimens at the individual particle level is discussed and electron optical issues and challenges to further improve resolution and contrast are considered. Copyright © 2018 Elsevier B.V. All rights reserved.

Space density and clustering properties of a new sample of emission-line galaxies

International Nuclear Information System (INIS)

Wasilewski, A.J.

1982-01-01

A moderate-dispersion objective-prism survey for low-redshift emission-line galaxies has been carried out in an 825 sq. deg. region of sky with the Burrell Schmidt telescope of Case Western Reserve University. A 4 0 prism (300 A/mm at H#betta#) was used with the Illa-J emulsion to show that a new sample of emission-line galaxies is available even in areas already searched with the excess uv-continuum technique. The new emission-line galaxies occur quite commonly in systems with peculiar morphology indicating gravitational interaction with a close companion or other disturbance. About 10 to 15% of the sample are Seyfert galaxies. It is suggested that tidal interaction involving matter infall play a significant role in the generation of an emission-line spectrum. The space density of the new galaxies is found to be similar to the space density of the Makarian galaxies. Like the Markarian sample, the galaxies in the present survey represent about 10% of all galaxies in the absolute magnitude range M/sub p/ = -16 to -22. The observations also indicate that current estimates of dwarf galaxy space densities may be too low. The clustering properties of the new galaxies have been investigated using two approaches: cluster contour maps and the spatial correlation function. These tests suggest that there is weak clustering and possibly superclustering within the sample itself and that the galaxies considered here are about as common in clusters of ordinary galaxies as in the field

On-line determination of manganese in solid seafood samples by flame atomic absorption spectrometry

International Nuclear Information System (INIS)

Yebra, M.C.; Moreno-Cid, A.

2003-01-01

Manganese is extracted on-line from solid seafood samples by a simple continuous ultrasound-assisted extraction system (CUES). This system is connected to an on-line manifold, which permits the flow-injection flame atomic absorption spectrometric determination of manganese. Optimisation of the continuous leaching procedure is performed by an experimental design. The proposed method allows the determination of manganese with a relative standard deviation of 0.9% for a sample containing 23.4 μg g -1 manganese (dry mass). The detection limit is 0.4 μg g -1 (dry mass) for 30 mg of sample and the sample throughput is ca. 60 samples per hour. Accurate results are obtained by measuring TORT-1 certified reference material. The procedure is finally applied to mussel, tuna, sardine and clams samples

Trace analysis of halogenated hydrocarbons in gaseous samples by on-line enrichment in an adsorption trap, on-column cold-trapping and capillary gas chromatography. I.Method and instrumentation

NARCIS (Netherlands)

Noij, T.H.M.; Fabian, P.; Borchers, R.; Janssen, F.; Cramers, C.A.M.G.; Rijks, J.A.

1987-01-01

A method is described for the determination of halocarbons in gaseous samples down to the ppt level (1:1012, v/v), consisting of successive on-line sub-ambient enrichment on an adsorbent, on-column cryofocusing, capillary gas chromatography and electron-capture detection. The quantitative aspects of

Opto-electronic scanning of colour pictures with P/sup 2/CCC-all solid state line sensors

Energy Technology Data Exchange (ETDEWEB)

Damann, H; Rabe, G; Zinke, M; Herrmann, M; Imjela, R; Laasch, I; Mueller, J; Neumann, K; Tauchen, G; Woelber, J

1982-04-01

A new one-chip all solid state line sensor (P/sup 2/CCD-Tricoli) has been realized as a basis for the opto-electronic scanning of colour pictures. The three photosensitive lines for the colour components red, green and blue contain each 652 photo elements. They are arranged in parallel on one silicon crystal, with distances of some 100 ..mu..m. The line sensor is supplied with an extra designed driving circuitry and a signal processing. For colour splitting a colour separating digital phase grating has been developed which generates the three colour components in its three central diffraction orders. Using all the development components ('Tricoli'-line-sensor, electronic circuitry, colour separation grating) a model of a slide scanner has been built up, which succesfully demonstrates the feasibility of the proposed colour scanning system.

Energetic electron anisotropies in the magnetotail - Identification of open and closed field lines

Science.gov (United States)

Baker, D. N.; Stone, E. C.

1976-01-01

Unidirectional anisotropies in the energetic electron fluxes (E greater than or equal to about 200 keV) have been observed in the earth's magnetotail with the Caltech Electron/Isotope Spectrometer on IMP-8. The anisotropies occur during periods of enhanced fluxes and provide essential information on the topology (open or closed) of the magnetotail field lines which are associated with recently identified acceleration regions.

The electron transport problem sampling by Monte Carlo individual collision technique

Energy Technology Data Exchange (ETDEWEB)

Androsenko, P.A.; Belousov, V.I. [Obninsk State Technical Univ. of Nuclear Power Engineering, Kaluga region (Russian Federation)

2005-07-01

The problem of electron transport is of most interest in all fields of the modern science. To solve this problem the Monte Carlo sampling has to be used. The electron transport is characterized by a large number of individual interactions. To simulate electron transport the 'condensed history' technique may be used where a large number of collisions are grouped into a single step to be sampled randomly. Another kind of Monte Carlo sampling is the individual collision technique. In comparison with condensed history technique researcher has the incontestable advantages. For example one does not need to give parameters altered by condensed history technique like upper limit for electron energy, resolution, number of sub-steps etc. Also the condensed history technique may lose some very important tracks of electrons because of its limited nature by step parameters of particle movement and due to weakness of algorithms for example energy indexing algorithm. There are no these disadvantages in the individual collision technique. This report presents some sampling algorithms of new version BRAND code where above mentioned technique is used. All information on electrons was taken from Endf-6 files. They are the important part of BRAND. These files have not been processed but directly taken from electron information source. Four kinds of interaction like the elastic interaction, the Bremsstrahlung, the atomic excitation and the atomic electro-ionization were considered. In this report some results of sampling are presented after comparison with analogs. For example the endovascular radiotherapy problem (P2) of QUADOS2002 was presented in comparison with another techniques that are usually used. (authors)

Precision measurements of high-energy conversion electron lines and determination of neutron binding energies

International Nuclear Information System (INIS)

Braumandl, F.

1979-01-01

The paper first discusses the energy accuracy of the BILL conversion electron spectrometer at the Grenoble high flux reactor. With an improved temperature stabilisation of the magnets, an energy accuracy of ΔE/E -5 can be reached. After this, highly exact measurements of high-energy conversion electron lines of the 200 Hg, 114 Cd, 165 Dy, 168 Er, 239 U nuclei and the 13 C, 28 Al 3 H and 92 Zr photoelectron lines were carried out. Energy calibration of the spectrometer was carried out in the 1.5 MeV to 6.5 MeV range with intensive high-energy transitions of the 200 Hg nucleus. Systematic calibration errors could be investigated by means of combinations between the calibration lines. A calibration for absolute energies was obtained by comparing low-energy gamma transitions of 200 Hg with the 411.8 keV gold standard. (orig.) [de

High peak current operation of x-ray free-electron laser multiple beam lines by suppressing coherent synchrotron radiation effects

Science.gov (United States)

Hara, Toru; Kondo, Chikara; Inagaki, Takahiro; Togawa, Kazuaki; Fukami, Kenji; Nakazawa, Shingo; Hasegawa, Taichi; Morimoto, Osamu; Yoshioka, Masamichi; Maesaka, Hirokazu; Otake, Yuji; Tanaka, Hitoshi

2018-04-01

The parallel operation of multiple beam lines is an important means to expand the opportunity of user experiments at x-ray free-electron laser (XFEL) facilities. At SPring-8 Angstrom free-electron laser (SACLA), the multi-beam-line operation had been tested using two beam lines, but transverse coherent synchrotron radiation (CSR) effects at a dogleg beam transport severely limited the laser performance. To suppress the CSR effects, a new beam optics based on two double bend achromat (DBA) structures was introduced for the dogleg. After the replacement of the beam optics, high peak current bunches of more than 10 kA are now stably transported through the dogleg and the laser pulse output is increased by a factor of 2-3. In the multi-beam-line operation of SACLA, the electron beam parameters, such as the beam energy and peak current, can be adjusted independently for each beam line. Thus the laser output can be optimized and wide spectral tunability is ensured for all beam lines.

A silicon photo-multiplier signal readout using strip-line and waveform sampling for Positron Emission Tomography

Science.gov (United States)

Kim, H.; Chen, C.-T.; Eclov, N.; Ronzhin, A.; Murat, P.; Ramberg, E.; Los, S.; Kao, C.-M.

2016-09-01

A strip-line and waveform sampling based readout is a signal multiplexing method that can efficiently reduce the readout channels while fully exploiting the fast time characteristics of photo-detectors such as the SiPM. We have applied this readout method for SiPM-based time-of-flight (TOF) positron emission tomography (PET) detectors. We have prototyped strip-line boards in which 8 SiPMs (pitch 5.2 mm) are connected by using a single strip-line, and the signals appearing at the ends of the strip-line are acquired by using the DRS4 waveform sampler at a nominal sampling frequency of 1-5 GS/s. Experimental tests using laser and LYSO scintillator are carried out to assess the performance of the strip-line board. Each SiPM position, which is inferred from the arrival time difference of the two signals at the ends of the strip-line, is well identified with 2.6 mm FWHM resolution when the SiPMs are coupled to LYSO crystals and irradiated by a 22Na source. The average energy and coincidence time resolution corresponding to 511 keV photons are measured to be ∼32% and ∼510 ps FWHM, respectively, at a 5.0 GS/s DRS4 sampling rate. The results show that the sampling rate can be lowered to 1.5 GS/s without performance degradation. These encouraging initial test results indicate that the strip-line and waveform sampling readout method is applicable for SiPM-based TOF PET development.

Study of semiconductor valence plasmon line shapes via electron energy-loss spectroscopy in the transmission electron microscope

International Nuclear Information System (INIS)

Kundmann, M.K.

1988-11-01

Electron energy-loss spectra of the semiconductors Si, AlAs, GaAs, InAs, InP, and Ge are examined in detail in the regime of outer-shell and plasmon energy losses (0--100eV). Particular emphasis is placed on modeling and analyzing the shapes of the bulk valence plasmon lines. A line shape model based on early work by Froehlich is derived and compared to single-scattering probability distributions extracted from the measured spectra. Model and data are found to be in excellent agreement, thus pointing the way to systematic characterization of the plasmon component of EELS spectra. The model is applied to three separate investigations. 82 refs

Electron velocity distribution function in a plasma with temperature gradient and in the presence of suprathermal electrons: application to incoherent-scatter plasma lines

Directory of Open Access Journals (Sweden)

P. Guio

Full Text Available The plasma dispersion function and the reduced velocity distribution function are calculated numerically for any arbitrary velocity distribution function with cylindrical symmetry along the magnetic field. The electron velocity distribution is separated into two distributions representing the distribution of the ambient electrons and the suprathermal electrons. The velocity distribution function of the ambient electrons is modelled by a near-Maxwellian distribution function in presence of a temperature gradient and a potential electric field. The velocity distribution function of the suprathermal electrons is derived from a numerical model of the angular energy flux spectrum obtained by solving the transport equation of electrons. The numerical method used to calculate the plasma dispersion function and the reduced velocity distribution is described. The numerical code is used with simulated data to evaluate the Doppler frequency asymmetry between the up- and downshifted plasma lines of the incoherent-scatter plasma lines at different wave vectors. It is shown that the observed Doppler asymmetry is more dependent on deviation from the Maxwellian through the thermal part for high-frequency radars, while for low-frequency radars the Doppler asymmetry depends more on the presence of a suprathermal population. It is also seen that the full evaluation of the plasma dispersion function gives larger Doppler asymmetry than the heat flow approximation for Langmuir waves with phase velocity about three to six times the mean thermal velocity. For such waves the moment expansion of the dispersion function is not fully valid and the full calculation of the dispersion function is needed.

Key words. Non-Maxwellian electron velocity distribution · Incoherent scatter plasma lines · EISCAT · Dielectric response function

Electron velocity distribution function in a plasma with temperature gradient and in the presence of suprathermal electrons: application to incoherent-scatter plasma lines

Directory of Open Access Journals (Sweden)

P. Guio

1998-10-01

Full Text Available The plasma dispersion function and the reduced velocity distribution function are calculated numerically for any arbitrary velocity distribution function with cylindrical symmetry along the magnetic field. The electron velocity distribution is separated into two distributions representing the distribution of the ambient electrons and the suprathermal electrons. The velocity distribution function of the ambient electrons is modelled by a near-Maxwellian distribution function in presence of a temperature gradient and a potential electric field. The velocity distribution function of the suprathermal electrons is derived from a numerical model of the angular energy flux spectrum obtained by solving the transport equation of electrons. The numerical method used to calculate the plasma dispersion function and the reduced velocity distribution is described. The numerical code is used with simulated data to evaluate the Doppler frequency asymmetry between the up- and downshifted plasma lines of the incoherent-scatter plasma lines at different wave vectors. It is shown that the observed Doppler asymmetry is more dependent on deviation from the Maxwellian through the thermal part for high-frequency radars, while for low-frequency radars the Doppler asymmetry depends more on the presence of a suprathermal population. It is also seen that the full evaluation of the plasma dispersion function gives larger Doppler asymmetry than the heat flow approximation for Langmuir waves with phase velocity about three to six times the mean thermal velocity. For such waves the moment expansion of the dispersion function is not fully valid and the full calculation of the dispersion function is needed.Key words. Non-Maxwellian electron velocity distribution · Incoherent scatter plasma lines · EISCAT · Dielectric response function

Sampling and sample preparation development for analytical and on-line measurement techniques of process liquids; Naeytteenoton ja kaesittelyn kehittaeminen prosessinesteiden analytiikan ja on-line mittaustekniikan tarpeisiin - MPKT 11

Energy Technology Data Exchange (ETDEWEB)

Karttunen, K. [Oulu Univ. (Finland)

1998-12-31

Main goal of the research project is to develop sampling and sample handling methods and techniques for pulp and paper industry to be used for analysis and on-line purposes. The research focus specially on the research and development of the classification and separation methods and techniques needed for liquid and colloidal substances as well as in ion analysis. (orig.)

Sampling and sample preparation development for analytical and on-line measurement techniques of process liquids; Naeytteenoton ja kaesittelyn kehittaeminen prosessinesteiden analytiikan ja on-line mittaustekniikan tarpeisiin - MPKT 11

Energy Technology Data Exchange (ETDEWEB)

Karttunen, K [Oulu Univ. (Finland)

1999-12-31

Main goal of the research project is to develop sampling and sample handling methods and techniques for pulp and paper industry to be used for analysis and on-line purposes. The research focus specially on the research and development of the classification and separation methods and techniques needed for liquid and colloidal substances as well as in ion analysis. (orig.)

Development of splitting convergent beam electron diffraction (SCBED)

Energy Technology Data Exchange (ETDEWEB)

Houdellier, Florent, E-mail: Florent.Houdellier@cemes.fr [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France); Röder, Falk [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France); Triebenberg Lab, Institut für Strukturphysik, Technische Universität Dresden, D-01062 Dresden (Germany); Snoeck, Etienne [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France)

2015-12-15

Using a combination of condenser electrostatic biprism with dedicated electron optic conditions for sample illumination, we were able to split a convergent beam electron probe focused on the sample in two half focused probes without introducing any tilt between them. As a consequence, a combined convergent beam electron diffraction pattern is obtained in the back focal plane of the objective lens arising from two different sample areas, which could be analyzed in a single pattern. This splitting convergent beam electron diffraction (SCBED) pattern has been tested first on a well-characterized test sample of Si/SiGe multilayers epitaxially grown on a Si substrate. The SCBED pattern contains information from the strained area, which exhibits HOLZ lines broadening induced by surface relaxation, with fine HOLZ lines observed in the unstrained reference part of the sample. These patterns have been analyzed quantitatively using both parts of the SCBED transmitted disk. The fine HOLZ line positions are used to determine the precise acceleration voltage of the microscope while the perturbed HOLZ rocking curves in the stained area are compared to dynamical simulated ones. The combination of these two information leads to a precise evaluation of the sample strain state. Finally, several SCBED setups are proposed to tackle fundamental physics questions as well as applied materials science ones and demonstrate how SCBED has the potential to greatly expand the range of applications of electron diffraction and electron holography. - Highlights: • Using a condenser biprism, we split the CBED pattern in two half-CBED disks. • We have determined the electron optical conditions used to perform various SCBED. • We propose new applications possible for this new SCBED configuration.

On the role of the gas environment, electron-dose-rate, and sample on the image resolution in transmission electron microscopy

DEFF Research Database (Denmark)

Ek, Martin; Jespersen, Sebastian Pirel Fredsgaard; Damsgaard, Christian Danvad

2016-01-01

on the electron-dose-rate. In this article, we demonstrate that both the total and areal electron-dose-rates work as descriptors for the dose-rate-dependent resolution and are related through the illumination area. Furthermore, the resolution degradation was observed to occur gradually over time after......The introduction of gaseous atmospheres in transmission electron microscopy offers the possibility of studying materials in situ under chemically relevant environments. The presence of a gas environment can degrade the resolution. Surprisingly, this phenomenon has been shown to depend...... initializing the illumination of the sample and gas by the electron beam. The resolution was also observed to be sensitive to the electrical conductivity of the sample. These observations can be explained by a charge buildup over the electron-illuminated sample area, caused by the beam–gas–sample interaction...

Non-impact modeling of electron broadening of hydrogen spectral lines in dense but relatively cold plasmas

International Nuclear Information System (INIS)

Ferri, S.; Buescher, S.; Wrubel, Th.; Kunze, H.-J.; Calisti, A.; Stamm, R.; Talin, B.

2001-01-01

The standard static-ion/impact-electron theory of line broadening is assessed with calculations of hydrogen lines over a broad range of plasma conditions. In most cases, discrepancies between results from theory and experiments are explained by the neglect of ion-dynamics effects. Nevertheless, recent experiments involving high density but low temperature plasmas indicate that ion-dynamics/impact-electron models may seriously overestimate the broadening for such conditions. We show that the observed discrepancies are not due to the ion modeling but due to the impact approximation of the electrons in the Original Frequency Fluctuation Model (FFM). This situation arises for plasma conditions where the interactions with the electrons are a major broadening mechanism and quasi-static, i.e. non-binary, electron effects are important. An alternative approach to a binary collision operator is therefore proposed by means of the FFM code generalized to the two components (ions and electrons) of the plasma. Accurate simulations accounting for the electron plus ion field dynamics have been used to corroborate the FFM as applied to both ion and electron perturbers, and good agreement is found with recent experiments on H α and P α for dense but relatively cold plasmas

Lean manufacturing implementation in reducing waste for electronic assembly line

Directory of Open Access Journals (Sweden)

Zakaria Nurul Husna

2017-01-01

Full Text Available Lean manufacturing is the most convenient way to eliminate unnecessary waste and can provide what customers demand. This paper presents possibilities and sustainability of application of lean manufacturing method by using a virtual simulation of the workers performance in a line production of small and medium industry. Actual case study and Witness simulation were used in this study to find the waste that exists in the production and identified the performance of workers in the production line. Lean manufacturing concept has identified and rectified problems related to low productivity in the assembly line. The case study is involved a line production for electronic part assembly. The result of this preliminary study should illustrate the relationship of worker’s performance by lean manufacturing method as well as the productivity improvements which help to reduce cost for manufacturer. Lean manufacturing method has been used during the study to reduce the cost when waste is eliminated by reducing the workstation without reducing the performance of the production. The performance of the production is increased when allocating the labor in a needed working area. Lastly, the study also proves that the new layout has improved the process to be used for future production process.

Anisotropic electron velocity distribution in an ECR helium plasma as determined from polarization of emission lines

International Nuclear Information System (INIS)

Iwamae, A; Sato, T; Horimoto, Y; Inoue, K; Fujimoto, T; Uchida, M; Maekawa, T

2005-01-01

A helium plasma is produced by electron-cyclotron resonance heating in a cusp-configuration magnetic field. Several neutral helium lines are found polarized in the direction perpendicular to the magnetic field; the maximum polarization degree exceeds 10%. The polarization degree and intensity of the emission lines yield, respectively, the alignment and population of the upper levels. The population-alignment collisional-radiative model is developed, and the experimental result is interpreted in terms of an anisotropic electron velocity distribution; it is of a Saturn-type with the central thermal component of 14 eV and the 'ring' component displaced by 9.2 eV from the central component. The relative number of 'ring' electrons is 40%. (letter to the editor)

An Analysis of Electronic Commerce Acquisition Systems: Comparison of a New Pure Electronic Purchasing and Exchange System (Electronic Storefront) and Other Legacy On-line Purchasing Systems

National Research Council Canada - National Science Library

Rowe, Arthur

2002-01-01

... as they relate to contracting and purchasing of supplies and services, The issues and concerns with legacy on-line procurement systems will be compared to a newly developed Pure Electronic Ordering System...

Energetic Electron Acceleration Observed by MMS in the Vicinity of an X-Line Crossing

Science.gov (United States)

Jaynes, A. N.; Turner, D. L.; Wilder, F. D.; Osmane, A.; Baker, D. N.; Blake, J. B.; Fennell, J. F.; Cohen, I. J.; Mauk, B. H.; Reeves, G. D.;

The influence of electron collisions on non-LTE Li line formation in stellar atmospheres

International Nuclear Information System (INIS)

Osorio, Yeisson; Barklem, Paul; Lind, Karin; Asplund, Martin

2012-01-01

The influence of the uncertainties in the rate coefficient data for electron-impact excitation and ionization on non-LTE Li line formation in cool stellar atmospheres is investigated. We examine the electron collision data used in previous non-LTE calculations and compare them to our own calculations using the R-matrix with pseudostates (RMPS) method and to other calculations found in the literature.

Electro-optic sampling for time resolving relativistic ultrafast electron diffraction

International Nuclear Information System (INIS)

Scoby, C. M.; Musumeci, P.; Moody, J.; Gutierrez, M.; Tran, T.

2009-01-01

The Pegasus laboratory at UCLA features a state-of-the-art electron photoinjector capable of producing ultrashort (<100 fs) high-brightness electron bunches at energies of 3.75 MeV. These beams recently have been used to produce static diffraction patterns from scattering off thin metal foils, and it is foreseen to take advantage of the ultrashort nature of these bunches in future pump-probe time-resolved diffraction studies. In this paper, single shot 2-d electro-optic sampling is presented as a potential technique for time of arrival stamping of electron bunches used for diffraction. Effects of relatively low bunch charge (a few 10's of pC) and modestly relativistic beams are discussed and background compensation techniques to obtain high signal-to-noise ratio are explored. From these preliminary tests, electro-optic sampling is suitable to be a reliable nondestructive time stamping method for relativistic ultrafast electron diffraction at the Pegasus lab.

Numerical study of electron-leakage power loss in a tri-plate transmission line

International Nuclear Information System (INIS)

Barker, R.J.; Goldstein, S.A.

1982-01-01

Numerical simulations have been conducted using NRL's DIODE2D computer code to model the steady-state behavior of electron flow in a radial diode and in its adjacent tri-plate transmission line (TTL). Particular attention was paid to the magnitude of the electron current flowing from the cathode to the anode surface in the TTL. A quantitative value for this effective power loss is given. The electron current is restricted mainly to the transition region in the TTL into which there is seepage of the B/sub z/ that is imposed in the diode gap. This finding highlights the importance of that region to diode designers

Design of modified annulus air sampling system for the detection of leakage in waste transfer line

International Nuclear Information System (INIS)

Deokar, U.V; Khot, A.R.; Mathew, P.; Ganesh, G.; Tripathi, R.M.; Srivastava, Srishti

2018-01-01

Various liquid waste streams are generated during the operation of reprocessing plant. The High Level (HL), Intermediate Level (IL) and Low Level (LL) liquid wastes generated, are transferred from reprocessing plant to Waste Management Facility. These respective waste streams are transferred through pipe-in-pipe lines along the shielded concrete trench. For detection of radioactive leakage from primary waste transfer line into secondary line, sampling of the annulus air between the two pipes is carried out. The currently installed pressurized annulus air sampling system did not have online leakage detection provision. Hence, there are chances of personal exposure and airborne activity in the working area. To overcome these design flaws, free air flow modified online annulus air sampling system with more safety features is designed

Issues for Bringing Electron Beam Irradiators On-Line

International Nuclear Information System (INIS)

Kaye, R.J.; Turman, B.N.

1999-01-01

Irradiation of red meat and poultry has been approved by the U.S. FDA, and the U.S. Department of Agriculture's rule for processing red meat is out for comment. Looking beyond the current issues of packaging materials, labeling, and consumer acceptance, this paper reviews the next step of implementation and how to remove, or at least reduce, the barriers to utilization. Polls of the user community identified their requirements for electron beam or x-ray processing of meat or poultry and their concerns about implementation for on-line processing. These needs and issues are compared to the capabilities of the accelerator industry. The critical issues of beam utilization and dose uniformity, factors affecting floor space requirements, and treatment costs are examined

Issues for Bringing Electron Beam Irradiators On-Line

Energy Technology Data Exchange (ETDEWEB)

Kaye, R.J.; Turman, B.N.

1999-04-20

Irradiation of red meat and poultry has been approved by the U.S. FDA, and the U.S. Department of Agriculture's rule for processing red meat is out for comment. Looking beyond the current issues of packaging materials, labeling, and consumer acceptance, this paper reviews the next step of implementation and how to remove, or at least reduce, the barriers to utilization. Polls of the user community identified their requirements for electron beam or x-ray processing of meat or poultry and their concerns about implementation for on-line processing. These needs and issues are compared to the capabilities of the accelerator industry. The critical issues of beam utilization and dose uniformity, factors affecting floor space requirements, and treatment costs are examined.

Automated Sample Exchange Robots for the Structural Biology Beam Lines at the Photon Factory

International Nuclear Information System (INIS)

Hiraki, Masahiko; Watanabe, Shokei; Yamada, Yusuke; Matsugaki, Naohiro; Igarashi, Noriyuki; Gaponov, Yurii; Wakatsuki, Soichi

2007-01-01

We are now developing automated sample exchange robots for high-throughput protein crystallographic experiments for onsite use at synchrotron beam lines. It is part of the fully automated robotics systems being developed at the Photon Factory, for the purposes of protein crystallization, monitoring crystal growth, harvesting and freezing crystals, mounting the crystals inside a hutch and for data collection. We have already installed the sample exchange robots based on the SSRL automated mounting system at our insertion device beam lines BL-5A and AR-NW12A at the Photon Factory. In order to reduce the time required for sample exchange further, a prototype of a double-tonged system was developed. As a result of preliminary experiments with double-tonged robots, the sample exchange time was successfully reduced from 70 seconds to 10 seconds with the exception of the time required for pre-cooling and warming up the tongs

Quantitating morphological changes in biological samples during scanning electron microscopy sample preparation with correlative super-resolution microscopy.

Science.gov (United States)

Zhang, Ying; Huang, Tao; Jorgens, Danielle M; Nickerson, Andrew; Lin, Li-Jung; Pelz, Joshua; Gray, Joe W; López, Claudia S; Nan, Xiaolin

2017-01-01

Sample preparation is critical to biological electron microscopy (EM), and there have been continuous efforts on optimizing the procedures to best preserve structures of interest in the sample. However, a quantitative characterization of the morphological changes associated with each step in EM sample preparation is currently lacking. Using correlative EM and superresolution microscopy (SRM), we have examined the effects of different drying methods as well as osmium tetroxide (OsO4) post-fixation on cell morphology during scanning electron microscopy (SEM) sample preparation. Here, SRM images of the sample acquired under hydrated conditions were used as a baseline for evaluating morphological changes as the sample went through SEM sample processing. We found that both chemical drying and critical point drying lead to a mild cellular boundary retraction of ~60 nm. Post-fixation by OsO4 causes at least 40 nm additional boundary retraction. We also found that coating coverslips with adhesion molecules such as fibronectin prior to cell plating helps reduce cell distortion from OsO4 post-fixation. These quantitative measurements offer useful information for identifying causes of cell distortions in SEM sample preparation and improving current procedures.

Balmer line diagnostic of electron heating at collisionless shocks in supernova remnants

International Nuclear Information System (INIS)

Rakowski, C.

2008-01-01

The mechanism and extent of electron heating at collisionless shocks has recently been under intense investigation. H α Balmer line emission is excited immediately behind the shock front and provides the best diagnostic for the electron to proton temperature ratio at supernova remnant shocks. Two components of emission are produced, a narrow component from electron and proton impact excitation of cold neutrals, and a broad component produced through charge exchange between the cold neutrals and the shock heated protons. Thus the broad and narrow component fluxes reflect the competition between electron and proton impact ionization, electron and proton impact excitation and charge exchange. This diagnostic has led to the discovery of an approximate inverse square relationship between the electron to proton temperature ratio and the shock velocity. In turn, this implies a constant level of electron heating, independent of shock speed above ∼ 450 km/s. In this talk I will present the observational evidence to date. Time permitting, I will introduce how lower-hybrid waves in an extended cosmic ray precursor could explain such a relationship, and how this and other parameters in the H α profile might relate to properties of cosmic rays and magnetic field amplification ahead of the shock. (author)

Electro-optic sampling at 90 degree interaction geometry for time-of-arrival stamping of ultrafast relativistic electron diffraction

Directory of Open Access Journals (Sweden)

C. M. Scoby

2010-02-01

Full Text Available In this paper we study a new geometry setup for electro-optic sampling (EOS where the electron beam runs parallel to the ⟨110⟩ face of a ZnTe crystal and the probe laser is perpendicular to it and to the beam path. The simple setup is used to encode the time-of-arrival information of a 3.5  MeV<10  pC electron bunch on the spatial profile of the laser pulse. The electric field lines inside the dielectric bend at an angle due to a relatively large (n∼3 index of refraction of the ZnTe crystal. We found theoretically and experimentally that the EOS signal can be maximized with a proper choice of incoming laser polarization angle. We achieved single-shot nondestructive measurement of the relative time of arrival between the pump and the probe beams thus improving the temporal resolution of ultrafast relativistic electron diffraction experiments.

Sample Development on Java Smart-Card Electronic Wallet Application

OpenAIRE

Toma Cristian

2009-01-01

In this paper, are highlighted concepts as: complete Java card application, life cycle of an applet, and a practical electronic wallet sample implemented in Java card technology. As a practical approach it would be interesting building applets for ID, Driving License, Health-Insurance smart cards, for encrypt and digitally sign documents, for E-Commerce and for accessing critical resources in government and military field. The end of this article it is presented a java card electronic wallet ...

Processing scarce biological samples for light and transmission electron microscopy

Directory of Open Access Journals (Sweden)

P Taupin

2008-06-01

Full Text Available Light microscopy (LM and transmission electron microscopy (TEM aim at understanding the relationship structure-function. With advances in biology, isolation and purification of scarce populations of cells or subcellular structures may not lead to enough biological material, for processing for LM and TEM. A protocol for preparation of scarce biological samples is presented. It is based on pre-embedding the biological samples, suspensions or pellets, in bovine serum albumin (BSA and bis-acrylamide (BA, cross-linked and polymerized. This preparation provides a simple and reproducible technique to process biological materials, present in limited quantities that can not be amplified, for light and transmission electron microscopy.

Time-dependent analysis of visible helium line-ratios for electron temperature and density diagnostic using synthetic simulations on NSTX-U

Energy Technology Data Exchange (ETDEWEB)

Muñoz Burgos, J. M., E-mail: jmunozbu@pppl.gov; Stutman, D.; Tritz, K. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Barbui, T.; Schmitz, O. [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2016-11-15

Helium line-ratios for electron temperature (T{sub e}) and density (n{sub e}) plasma diagnostic in the Scrape-Off-Layer (SOL) and edge regions of tokamaks are widely used. Due to their intensities and proximity of wavelengths, the singlet, 667.8 and 728.1 nm, and triplet, 706.5 nm, visible lines have been typically preferred. Time-dependency of the triplet line (706.5 nm) has been previously analyzed in detail by including transient effects on line-ratios during gas-puff diagnostic applications. In this work, several line-ratio combinations within each of the two spin systems are analyzed with the purpose of eliminating transient effects to extend the application of this powerful diagnostic to high temporal resolution characterization of plasmas. The analysis is done using synthetic emission modeling and diagnostic for low electron density NSTX SOL plasma conditions by several visible lines. Quasi-static equilibrium and time-dependent models are employed to evaluate transient effects of the atomic population levels that may affect the derived electron temperatures and densities as the helium gas-puff penetrates the plasma. The analysis of a wider range of spectral lines will help to extend this powerful diagnostic to experiments where the wavelength range of the measured spectra may be constrained either by limitations of the spectrometer or by other conflicting lines from different ions.

Measurement of the central ion and electron temperature of tokamak plasmas from the x-ray line radiation of high-Z impurity ions

International Nuclear Information System (INIS)

Bitter, M.; von Goeler, S.; Goldman, M.; Hill, K.W.; Horton, R.; Roney, W.; Sauthoff, N.; Stodiek, W.

1982-04-01

This paper describes measurements of the central ion and electron temperature of tokamak plasmas from the observation of the 1s - 2p resonance lines, and the associated dielectronic (1s 2 nl - 1s2pnl, with n greater than or equal to 2) satellites, of helium-like iron (Fe XXV) and titanium (Ti XXI). The satellite to resonance line ratios are very sensitive to the electron temperature and are used as an electron temperature diagnostic. The ion temperature is deduced from the Doppler width of the 1s - 2p resonance lines. The measurements have been performed with high resolution Bragg crystal spectrometers on the PLT (Princeton Large Torus) and PDX (Poloidal Divertor Experiment) tokamaks. The details of the experimental arrangement and line evaluation are described, and the ion and electron temperature results are compared with those obtained from independent diagnostic techniques, such as the analysis of charge-exchange neutrals and measurements of the electron cyclotron radiation. The obtained experimental results permit a detailed comparison with theoretical predictions

The retention of iodine in stainless steel sample lines

Energy Technology Data Exchange (ETDEWEB)

Evans, G.J.; Deir, C. [Univ. of Toronto (Canada); Ball, J.M. [Whiteshell Laboratories, Pinawa (Canada)

1995-02-01

Following an accident in a multi-unit CANDU nuclear generating station, decontamination of air vented from containment would play a critical role in minimizing the release of iodine to the environment. The concentration of gas phase iodine in containment air would be measured using the post accident radiation monitoring system, requiring that air samples be passed through a considerable length of tubing to a remote location where the desired measurements could safely be made. A significant loss of iodine, due to adsorption on the sample line surfaces, could greatly distort the measurement. In this study, the retention of I{sub 2}(g) on stainless steel was evaluated in bench scale experiments in order to evaluate, and if possible minimise, the extent of any such line losses. Experiments at the University of Toronto were performed using 6 inch lengths of 1/4 inch stainless steel tubing. Air, containing I-131 labelled I{sub 2}(g), ranging in concentration from 10{sup {minus}10} to 10{sup {minus}6} mol/dm{sup 3} and relative humidity (:RH) from 20 to 90 %, was passed through tubing samples maintained at temperatures ranging from 25 to 90{degrees}C. Adsorption at low gas phase iodine concentrations differed substantially from that at higher concentrations. The rate of deposition was proportional to the gas phase concentration, giving support to the concept of a first order deposition velocity. The surface loading increased with increasing relative humidity, particularly at low RH values, while the deposition rate decreased with increasing temperature. Surface water on the steel may play an important role in the deposition process. The chemisorbed iodine was located primarily in areas of corrosion. Furthermore, water used to wash the steel contained Fe, Mn and iodine in the form of iodide, suggesting that I{sub 2} reacted to form metal iodides. The deposition of I{sub 2} was also found to depend on the initial surface condition.

CORRELATION ANALYSIS OF A LARGE SAMPLE OF NARROW-LINE SEYFERT 1 GALAXIES: LINKING CENTRAL ENGINE AND HOST PROPERTIES

International Nuclear Information System (INIS)

Xu Dawei; Komossa, S.; Wang Jing; Yuan Weimin; Zhou Hongyan; Lu Honglin; Li Cheng; Grupe, Dirk

2012-01-01

We present a statistical study of a large, homogeneously analyzed sample of narrow-line Seyfert 1 (NLS1) galaxies, accompanied by a comparison sample of broad-line Seyfert 1 (BLS1) galaxies. Optical emission-line and continuum properties are subjected to correlation analyses, in order to identify the main drivers of the correlation space of active galactic nuclei (AGNs), and of NLS1 galaxies in particular. For the first time, we have established the density of the narrow-line region as a key parameter in Eigenvector 1 space, as important as the Eddington ratio L/L Edd . This is important because it links the properties of the central engine with the properties of the host galaxy, i.e., the interstellar medium (ISM). We also confirm previously found correlations involving the line width of Hβ and the strength of the Fe II and [O III] λ5007 emission lines, and we confirm the important role played by L/L Edd in driving the properties of NLS1 galaxies. A spatial correlation analysis shows that large-scale environments of the BLS1 and NLS1 galaxies of our sample are similar. If mergers are rare in our sample, accretion-driven winds, on the one hand, or bar-driven inflows, on the other hand, may account for the strong dependence of Eigenvector 1 on ISM density.

The effect of sidewall roughness on line edge roughness in top-down scanning electron microscopy images

Science.gov (United States)

Verduin, T.; Lokhorst, S. R.; Kruit, P.; Hagen, C. W.

2015-03-01

We have investigated in a numerical study the determination of sidewall roughness (SWR) from top down scanning electron microscopy (SEM) images. In a typical metrology application, top-down SEM images are acquired in a (critical-dimension) SEM and the roughness is analyzed. However, the true size, shape and roughness characteristics of resist features are not fully investigated in the analysis of top-down SEM images. In reality, rough resist features are complex three-dimensional structures and the characterization naturally extends to the analysis of SWR. In this study we randomly generate images of rough lines and spaces, where the lines are made of PMMA on a silicon substrate. The lines that we study have a length of 2 µm, a width of 32nm and a height of 32 nm. The SWR is modeled by using the power spectral density (PSD) function of Palasantzas, which characterizes roughness by the standard deviation σ, correlation length ξ and roughness exponent α . The actual roughness is generated by application of the method of Thorsos in two dimensions. The images are constructed by using a home-built program for simulating electron-specimen interactions. The program that we have developed is optimized for complex arbitrary geometries and large number of incident low energy primary electrons by using multi-core CPUs and GPUs. The program uses the dielectric function model for inelastic scattering events and has an implementation specifically for low energy electrons. A satisfactory comparison is made between the secondary electron yields from the home-built program and another program found in literature. In order to reduce the risk of shrinkage, we use a beam energy of 300 eV and a spot size of 3 nm. Each pixel is exposed with 20 electrons on average (≍ 276 µC/cm2), following the Poisson distribution to account for illumination shot noise. We have assumed that the detection of electrons is perfect and does not introduce additional noise. We measure line edge

Effects of Electron Flow Current Density on Flow Impedance of Magnetically Insulated Transmission Lines

International Nuclear Information System (INIS)

He Yong; Zou Wen-Kang; Song Sheng-Yi

2011-01-01

In modern pulsed power systems, magnetically insulated transmission lines (MITLs) are used to couple power between the driver and the load. The circuit parameters of MITLs are well understood by employing the concept of flow impedance derived from Maxwell's equations and pressure balance across the flow. However, the electron density in an MITL is always taken as constant in the application of flow impedance. Thus effects of electron flow current density (product of electron density and drift velocity) in an MITL are neglected. We calculate the flow impedances of an MITL and compare them under three classical MITL theories, in which the electron density profile and electron flow current density are different from each other. It is found that the assumption of constant electron density profile in the calculation of the flow impedance is not always valid. The electron density profile and the electron flow current density have significant effects on flow impedance of the MITL. The details of the electron flow current density and its effects on the operation impedance of the MITL should be addressed more explicitly by experiments and theories in the future. (nuclear physics)

105-K east sandfilter backwash line sample analysis report: Third campaign

International Nuclear Information System (INIS)

Miller, G.L.; Bechtold, D.B.

1996-01-01

This project seeks to produce uranium (U) and plutonium (Pu) analyses of samples taken from the KE basin filter backwash line each time the sand filter is backwashed. K Basin operations will use the analytical results to determine additions of fissile materials to the backwash sludge pit and thereby maintain a running inventory of fissile elements in the pit. K Basin operations must not exceed a certain total inventory in order to be within a criticality specification. The third campaign of this project consisted of three samples, numbered by the customer 245KEB, 246KEB, and 247KEB. A revised letter of instruction controlled their processing

Two-dimensional electron flow in pulsed power transmission lines and plasma opening switches

International Nuclear Information System (INIS)

Church, B.W.; Longcope, D.W.; Ng, C.K.; Sudan, R.N.

1991-01-01

The operation of magnetically insulated transmission lines (MITL) and the interruption of current in a plasma opening switch (POS) are determined by the physics of the electrons emitted by the cathode surface. A mathematical model describes the self-consistent two-dimensional flow of an electron fluid. A finite element code, FERUS, has been developed to solve the two equations which describe Poisson's and Ampere's law in two dimensions. The solutions from this code are obtained for parameters where the electron orbits are considerably modified by the self-magnetic field of the current. Next, the self-insulated electron flow in a MITL with a step change in cross-section is studied using a conventional two-dimensional fully electromagnetic particle-in-cell code, MASK. The equations governing two-dimensional quasi-static electron flow are solved numerically by a third technique which is suitable for predicting current interruption in a POS. The object of the study is to determine the critical load impedance, Z CL , required for current interruption for a given applied voltage, cathode voltage and plasma length. (author). 9 refs, 5 figs

Setup error in radiotherapy: on-line correction using electronic kilovoltage and megavoltage radiographs

International Nuclear Information System (INIS)

Pisani, Laura; Lockman, David; Jaffray, David; Yan Di; Martinez, Alvaro; Wong, John

2000-01-01

applied by translating the treatment couch in the lateral, superior-to-inferior and vertical directions only. During treatment, kV open-field images were acquired for off-line treatment verification and analysis. Each patient study spanned 2-6 weeks. The 14 patient studies were completed with 8248 electronic images acquired and analyzed. Results: Results from the phantom studies showed that the users were able to detect the applied translational shift to better than 2 mm, and mostly to within 1 mm. The intraobserver variability of template alignment was on the order of 1 mm using a sample of either MV or kV patient images. The difference between using MV or kV images was significant for only a few cases. However in most cases, interobserver alignment variability was larger when using MV images than kV. For on-line setup correction, the study procedure added 10 min. to conventional treatment time. Setup variation measured with either kV- or MV-localization images was similar. The initial magnitude of setup error was appreciable, with a mean displacement of about 6.6 no. +-no. 2.4 mm for the 14 patients. On-line correction using either kV- or MV-localization images improved setup accuracy. Over all study patients, setup errors occurred with standard deviations greater than 2 mm in any direction with a frequency of 48% before correction, and were reduced to 16% after correction. On average, kV image-based correction reduced radial setup variation to 2.6 no. +-no. 1.6 mm compared to the 3.3 no. +-no. 1.8 mm attained using MV images. The difference detected between the kV and MV data was not statistically significant when averaged over all patients. However, for on-line corrections in the neck and thoracic regions, using kV-localization images reduced setup error significantly more than using MV images. Conclusions: In our anatomic template alignment study, interobserver variability was smaller using kV images than MV images. Intraobserver variability was smaller for

Evaluation of different continuous cell lines in the isolation of mumps virus by the shell vial method from clinical samples

Science.gov (United States)

Reina, J; Ballesteros, F; Mari, M; Munar, M

2001-01-01

Aims—To compare prospectively the efficacy of the Vero, LLC-MK2, MDCK, Hep-2, and MRC-5 cell lines in the isolation of the mumps virus from clinical samples by means of the shell vial method. Methods—During an epidemic outbreak of parotiditis 48 clinical samples (saliva swabs and CSF) were studied. Two vials of the Vero, LLC-MK2, MDCK, MRC-5, and Hep-2 cell lines were inoculated with 0.2 ml of the samples by the shell vial assay. The vials were incubated at 36°C for two and five days. The vials were then fixed with acetone at -20°C for 10 minutes and stained by a monoclonal antibody against mumps virus by means of an indirect immunofluorescence assay. Results—The mumps virus was isolated from 36 samples. The Vero and LLC-MK2 cell lines showed a 100% isolation capacity, MDCK showed 77.7%, MRC-5 showed 44.4%, and Hep-2 showed 22.2%. The Vero and LLC-MK2 lines were significantly different to the other cell lines (p 5 infectious foci) were 94.4% for Vero, 97.2% for LLC-MK2, 5.5% for MDCK, 5.5% for Hep-2, and 0% for MRC-5. Conclusions—The Vero and LLC-MK2 cell lines are equally efficient at two and five days incubation for the isolation of the mumps virus from clinical samples, and the use of the shell vial method considerably shortens the time of aetiological diagnosis with higher specificity. Key Words: mumps virus • Vero cell line • LLC-MK2 cell line • MDCK cell line • Hep-2 cell line • MRC-5 cell line • isolation • shell vial PMID:11729211

Utility and recognition of lines and linear patterns on electronic displays depicting aeronautical charting information

Science.gov (United States)

2009-01-01

This report describes a study conducted to explore the utility and recognition of lines and linear patterns on electronic displays depicting aeronautical charting information. The study gathered data from a large number of pilots who conduct all type...

High power, high brightness electron beam generation in a pulse-line driven pseudospark discharge

International Nuclear Information System (INIS)

Destler, W.W.; Segalov, Z.; Rodgers, J.; Ramaswamy, K.; Reiser, M.

1993-01-01

High brightness (∼10 10 A/m 2 rad 2 ), high power density (∼10 10 W/cm 2 ) electron beams have been generated by the mating of a hollow-cathode discharge device operating in the pseudospark regime to the output of a high power pulse line accelerator. Very small diameter (∼1 mm) electron beams with currents in the range 500--1000 A and energies in the range 150--300 keV have been generated with effective emittances estimated to be at or below 170 mm mrad. Such emittances are comparable to those achieved in conventional electron beam sources at current densities several orders of magnitude lower than those observed in these experiments

Derivation of electron density and temperature from (S II) and (O II) line intensity ratios

Energy Technology Data Exchange (ETDEWEB)

Canto, J; Meaburn, J; Theokas, A C [Manchester Univ. (UK). Dept of Astronomy; Elliott, K H [Anglo-Australian Observatory, Epping (Australia)

1980-12-01

Line intensity ratios for (S II) and (O II) due to collisional de-excitation are briefly discussed. Comparison is made between various reaction rate parameters presented by separate investigators. Included are observations of ratios obtained from the Orion nebula which experimentally confirm the reaction rates of Pradhan as best representing the observed distribution of these ratios. (O II) and (S II) contour plots are also presented, which allow effective electron temperatures and densities to be estimated from pairs of line ratios.

Electronic books. On-line access to the full-texts of non periodical documents

International Nuclear Information System (INIS)

Svrsek, L.

2004-01-01

This presentation describes several options how electronic books (technical handbooks, scientific books, reference works, etc.) are published and available on-line on the Internet. There is a short description of some of the major services provided by worldwide publishers. As a part of the presentation there will be a live demonstration of selected services and work slices of the most interested systems. (author)

Design of the extraction arc for the 2nd beam line of the free-electron laser FLASH

International Nuclear Information System (INIS)

Scholz, Matthias

2014-01-01

In this thesis, I deal with the design of the extraction arc for the second beam line of FLASH, an FEL (Free-Electron Laser) user facility at DESY Hamburg. Both beam lines will use the same linear accelerator and their separation will take place behind the last accelerating module. I present the constraints for the extraction arc given by the beam line layout of the existing machine, by the building environment of the new beam line and in particular, by coherent synchrotron radiation (CSR). The impact from CSR is presented, and I show how to mitigate these effects and what that means for the beam line design. The optimization of the extraction arc was done applying the downhill simplex algorithm which is presented, first in its basic form to explain the operation principle and then in a more advanced version as used in the applied program. I introduce in this thesis the final layout of the extraction arc including the following matching section. This layout fulfills all given constraints and can provide the required electron beam quality for FEL operation. In order to prove this, I present start-to-end simulations for different bunch charges and for two different wavelengths.

Determination of line edge roughness in low dose top-down scanning electron microscopy images

Science.gov (United States)

Verduin, T.; Kruit, P.; Hagen, C. W.

2014-04-01

We investigated off-line metrology for LER determination in low-dose SEM images to reduce the acquisition time and the risk of shrinkage. Our first attempts are based on filtering noisy (experimental) SEM images and use peak detection to measure the edge displacements and calculating the discrete PSD. However, the result of the filtering is that the power spectrum of the filter leaks into the PSD. So it is better to avoid a filter at all. We subsequently developed a method to detect edge displacements without the use of a filter. This method considers the signal profile of a SEM by integrating an experimental image of lines in the direction of the edges. The signal profile of an isolated edge is modeled as two merged Gaussians. This signal profile is then fitted against the raw (unfiltered) data of the edge pattern using an interior trust-region-reflective minimization procedure. This gives the edge displacements without the use of a filter and a filter-free version of the discrete PSD is obtained. The determination of edge displacements without the use of a filter, enables us to study how much noise is acceptable and still determine LER. To answer this question we generate random lines using the model of Palasantzas and the algorithm of Thorsos. This gives random generated edge displacements for typical values of experimental lines for the parameters of the model: 2 μm long lines (256 pixels), a correlation length ξ of 25 nm and a roughness exponent of 0.75. A noise-free top-down SEM-like image of lines is created by shifting the profile signal according to the random generated edge displacements. The image is further processed by adding Poisson-distributed noise. We consider three noise cases where the average electron density is about 2, 20 and 200 electrons per pixel. This corresponds to a charge density of (in respective order) 10 μC/cm2, 100 μC/cm2 and 1000 μC/cm2. The edge displacements of the random generated images are determined using our new

MID-INFRARED ATOMIC FINE-STRUCTURE EMISSION-LINE SPECTRA OF LUMINOUS INFRARED GALAXIES: SPITZER/IRS SPECTRA OF THE GOALS SAMPLE

Energy Technology Data Exchange (ETDEWEB)

Inami, H. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Armus, L.; Stierwalt, S.; Díaz-Santos, T.; Surace, J.; Howell, J.; Marshall, J. [Spitzer Science Center, California Institute of Technology, CA 91125 (United States); Charmandaris, V. [Department of Physics and Institute of Theoretical and Computational Physics, University of Crete, GR-71003 Heraklion (Greece); Groves, B. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Kewley, L. [Research School of Astronomy and Astrophysics, The Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Petric, A. [Department of Astronomy, California Institute of Technology, MS 320-47, Pasadena, CA 91125 (United States); Rich, J. [The Observatories, Carnegie Institute of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Haan, S. [CSIRO Astronomy and Space Science, Marsfield, NSW 2122 (Australia); Evans, A. S. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States); Mazzarella, J.; Lord, S. [Infrared Processing and Analysis Center, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Appleton, P. [NASA Herschel Science Center, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Spoon, H. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Frayer, D. [National Radio Astronomy Observatory, P.O. Box 2, Green Bank, WV 24944 (United States); Matsuhara, H., E-mail: inami@noao.edu [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (Japan); and others

2013-11-10

We present the data and our analysis of mid-infrared atomic fine-structure emission lines detected in Spitzer/Infrared Spectrograph high-resolution spectra of 202 local Luminous Infrared Galaxies (LIRGs) observed as part of the Great Observatories All-sky LIRG Survey (GOALS). We readily detect emission lines of [S IV], [Ne II], [Ne V], [Ne III], [S III]{sub 18.7{sub μm}}, [O IV], [Fe II], [S III]{sub 33.5{sub μm}}, and [Si II]. More than 75% of these galaxies are classified as starburst-dominated sources in the mid-infrared, based on the [Ne V]/[Ne II] line flux ratios and equivalent width of the 6.2 μm polycyclic aromatic hydrocarbon feature. We compare ratios of the emission-line fluxes to those predicted from stellar photo-ionization and shock-ionization models to constrain the physical and chemical properties of the gas in the starburst LIRG nuclei. Comparing the [S IV]/[Ne II] and [Ne III]/[Ne II] line ratios to the Starburst99-Mappings III models with an instantaneous burst history, the emission-line ratios suggest that the nuclear starbursts in our LIRGs have ages of 1-4.5 Myr, metallicities of 1-2 Z{sub ☉}, and ionization parameters of 2-8 × 10{sup 7} cm s{sup –1}. Based on the [S III]{sub 33.5{sub μm}}/[S III]{sub 18.7{sub μm}} ratios, the electron density in LIRG nuclei is typically one to a few hundred cm{sup –3}, with a median electron density of ∼300 cm{sup –3}, for those sources above the low density limit for these lines. We also find that strong shocks are likely present in 10 starburst-dominated sources of our sample. A significant fraction of the GOALS sources (80) have resolved neon emission-line profiles (FWHM ≥600 km s{sup –1}) and five show clear differences in the velocities of the [Ne III] or [Ne V] emission lines, relative to [Ne II], of more than 200 km s{sup –1}. Furthermore, six starburst and five active galactic nucleus dominated LIRGs show a clear trend of increasing line width with ionization potential

Line radiation of multicharged ions with the Fermi-Dirac level distribution of electrons at high temperatures

International Nuclear Information System (INIS)

Garanin, S.F.

2003-01-01

Line radiation of multicharged ions with the Fermi-Dirac electron distribution by levels in the range of plasma temperatures, when electron movement may be considered quasiclassical, while potential, in which they move, is the Coulomb one, is considered. The spectrum and intensity of ion radiation are calculated. Within high plasma densities the radiation intensity per one ion proved to be independent of density and proportional to T 2 [ru

Development of a New Microextraction Fiber Combined to On-Line Sample Stacking Capillary Electrophoresis UV Detection for Acidic Drugs Determination in Real Water Samples

Science.gov (United States)

Araujo, Lilia; Prieto, Avismelsi; Navalón, Alberto; Vílchez, José Luis; Valera, Paola; Zambrano, Ana; Dugas, Vincent

2017-01-01

A new analytical method coupling a (off-line) solid-phase microextraction with an on-line capillary electrophoresis (CE) sample enrichment technique was developed for the analysis of ketoprofen, naproxen and clofibric acid from water samples, which are known as contaminants of emerging concern in aquatic environments. New solid-phase microextraction fibers based on physical coupling of chromatographic supports onto epoxy glue coated needle were studied for the off-line preconcentration of these micropollutants. Identification and quantification of such acidic drugs were done by capillary zone electrophoresis (CZE) using ultraviolet diode array detection (DAD). Further enhancement of concentration sensitivity detection was achieved by on-line CE “acetonitrile stacking” preconcentration technique. Among the eight chromatographic supports investigated, Porapak Q sorbent showed higher extraction and preconcentration capacities. The screening of parameters that influence the microextraction process was carried out using a two-level fractional factorial. Optimization of the most relevant parameters was then done through a surface response three-factor Box-Behnken design. The limits of detection and limits of quantification for the three drugs ranged between 0.96 and 1.27 µg∙L−1 and 2.91 and 3.86 µg∙L−1, respectively. Recovery yields of approximately 95 to 104% were measured. The developed method is simple, precise, accurate, and allows quantification of residues of these micropollutants in Genil River water samples using inexpensive fibers. PMID:28686186

Development of a New Microextraction Fiber Combined to On-Line Sample Stacking Capillary Electrophoresis UV Detection for Acidic Drugs Determination in Real Water Samples

Directory of Open Access Journals (Sweden)

Maria Espina-Benitez

2017-07-01

Full Text Available A new analytical method coupling a (off-line solid-phase microextraction with an on-line capillary electrophoresis (CE sample enrichment technique was developed for the analysis of ketoprofen, naproxen and clofibric acid from water samples, which are known as contaminants of emerging concern in aquatic environments. New solid-phase microextraction fibers based on physical coupling of chromatographic supports onto epoxy glue coated needle were studied for the off-line preconcentration of these micropollutants. Identification and quantification of such acidic drugs were done by capillary zone electrophoresis (CZE using ultraviolet diode array detection (DAD. Further enhancement of concentration sensitivity detection was achieved by on-line CE “acetonitrile stacking” preconcentration technique. Among the eight chromatographic supports investigated, Porapak Q sorbent showed higher extraction and preconcentration capacities. The screening of parameters that influence the microextraction process was carried out using a two-level fractional factorial. Optimization of the most relevant parameters was then done through a surface response three-factor Box-Behnken design. The limits of detection and limits of quantification for the three drugs ranged between 0.96 and 1.27 µg∙L−1 and 2.91 and 3.86 µg∙L−1, respectively. Recovery yields of approximately 95 to 104% were measured. The developed method is simple, precise, accurate, and allows quantification of residues of these micropollutants in Genil River water samples using inexpensive fibers.

Development of a New Microextraction Fiber Combined to On-Line Sample Stacking Capillary Electrophoresis UV Detection for Acidic Drugs Determination in Real Water Samples.

Science.gov (United States)

Espina-Benitez, Maria; Araujo, Lilia; Prieto, Avismelsi; Navalón, Alberto; Vílchez, José Luis; Valera, Paola; Zambrano, Ana; Dugas, Vincent

2017-07-07

A new analytical method coupling a (off-line) solid-phase microextraction with an on-line capillary electrophoresis (CE) sample enrichment technique was developed for the analysis of ketoprofen, naproxen and clofibric acid from water samples, which are known as contaminants of emerging concern in aquatic environments. New solid-phase microextraction fibers based on physical coupling of chromatographic supports onto epoxy glue coated needle were studied for the off-line preconcentration of these micropollutants. Identification and quantification of such acidic drugs were done by capillary zone electrophoresis (CZE) using ultraviolet diode array detection (DAD). Further enhancement of concentration sensitivity detection was achieved by on-line CE "acetonitrile stacking" preconcentration technique. Among the eight chromatographic supports investigated, Porapak Q sorbent showed higher extraction and preconcentration capacities. The screening of parameters that influence the microextraction process was carried out using a two-level fractional factorial. Optimization of the most relevant parameters was then done through a surface response three-factor Box-Behnken design. The limits of detection and limits of quantification for the three drugs ranged between 0.96 and 1.27 µg∙L -1 and 2.91 and 3.86 µg∙L -1 , respectively. Recovery yields of approximately 95 to 104% were measured. The developed method is simple, precise, accurate, and allows quantification of residues of these micropollutants in Genil River water samples using inexpensive fibers.

Electron Spin Resonance (ESR) studies of returned comet nucleus samples

International Nuclear Information System (INIS)

Tsay, Fundow; Kim, S.S.; Liang, R.H.

1989-01-01

The most important objective of the Comet Nucleus Sample Returm Mission is to return samples which could reflect formation conditions and evolutionary processes in the early solar nebula. It is expected that the returned samples will consist of fine-grained silicate materials mixed with ices composed of simple molecules such as H 2 O, NH 3 , CH 4 as well as organics and/or more complex compounds. Because of the exposure to ionizing radiation from cosmic-ray, gamma-ray, and solar wind protons at low temperature, free radicals are expected to be formed and trapped in the solid ice matrices. The kind of trapped radical species together with their concentration and thermal stability can be used as a dosimeter as well as a geothermometer to determine thermal and radiation histories as well as outgassing and other possible alternation effects since the nucleus material was formed. Since free radicals that are known to contain unpaired electrons are all paramagnetic in nature, they can be readily detected and characterized in their native form by the Electron Spin Resonance (ESR) method. In fact, ESR has been shown to be a non-destructive, highly sensitive tool for the detection and characterization of paramagnetic, ferromagnetic, and radiation damage centers in terrestrial and extraterrestrial geological samples. The potential use of ESR as an effective method in the study of returned comet nucleus samples, in particular, in the analysis of fine-grained solid state icy samples is discussed

Measuring the electron density in plasmas from the difference of Lorentzian part of the widths of two Balmer series hydrogen lines

Energy Technology Data Exchange (ETDEWEB)

Yubero, C. [Grupo de Física de Plasmas: Diagnosis, Modelos y Aplicaciones (FQM-136), Edificio A. Einstein (C-2), Campus de Rabanales, Universidad de Córdoba, 14071 Córdoba (Spain); García, M.C., E-mail: fa1gamam@uco.es [Grupo de Física de Plasmas: Diagnosis, Modelos y Aplicaciones (FQM-136), Edificio A. Einstein (C-2), Campus de Rabanales, Universidad de Córdoba, 14071 Córdoba (Spain); Dimitrijevic, M.S. [Astronomical Observatory, Volgina 7, 11060 Belgrade (Serbia); Sola, A.; Gamero, A. [Grupo de Física de Plasmas: Diagnosis, Modelos y Aplicaciones (FQM-136), Edificio A. Einstein (C-2), Campus de Rabanales, Universidad de Córdoba, 14071 Córdoba (Spain)

2015-05-01

We present an alternative optical emission spectroscopy method to measure the plasma electron density from the difference of widths of two Balmer series hydrogen lines (H{sub α} and H{sub β}), especially convenient for non-thermal plasmas since with this method, there is no need to know either the gas temperature or the van der Waals contribution to the Lorentzian part of the line. In this paper it has been assumed that the part of full width at half maximum due to Stark broadening can be determined with the approximation of Lorentzian line shape. The method has been applied to the determination of the electron density in an argon microwave-induced plasma maintained at atmospheric pressure, and comparison with the results obtained using other diagnostic methods has been done. - Highlights: • An alternative method to measure the electron density in plasmas from two Balmer series hydrogen lines (H{sub α} and H{sub β}) is presented. • The method is very convenient for plasmas with electron densities of the order of 10{sup 14} cm{sup −3} and above, at low gas temperatures. • It has been applied to the determination of the electron density of an argon microwave plasma at atmospheric pressure. • Results from it are in good agreement with previous ones obtained using other diagnostic methods.

Flow injection microfluidic device with on-line fluorescent derivatization for the determination of Cr(III) and Cr(VI) in water samples after solid phase extraction

Energy Technology Data Exchange (ETDEWEB)

Peng, Guilong [Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing, 400045 (China); Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084 (China); He, Qiang, E-mail: heqiang0980@163.com [Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing, 400045 (China); Lu, Ying [Department of Mathematics and Physics, Armed Police College, Chengdu, 610213 (China); Huang, Jing [Research Center for Advanced Computation, College of Science, Xihua University, Chengdu, 610039 (China); Lin, Jin-Ming, E-mail: jmlin@mail.tsinghua.edu.cn [Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084 (China)

2017-02-22

In this paper, a rapid and simple method using magnetic multi-walled carbon nanotubes (MWCNTS), as a solid-phase extraction (SPE) sorbent, was successfully developed for extraction and preconcentration trace amounts of Cr(III) in water samples. The synthesized magnetic-MWCNTs nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). A rhodamine derivative (R1) was synthesized and characterized as a highly selective and sensitive fluorescent derivatizing agent for Cr(III). After SPE procedure, Cr(III) analysis was performed by flow injection microfluidic chip with on-line fluorescent derivatization and laser-induced fluorescence (LIF) spectroscopy detection. The parameters, which affected the efficiency of the developed method were investigated and optimized. Under the optimized conditions, the method exhibited a linear dynamic range of 0–10.0 nM, with a detection limit of 0.094 nM and an enrichment factor of 38. Furthermore, real water samples were analyzed and good recoveries were obtained from 91.0 to 101.6%. - Graphical abstract: Flow injection microfluidic device with on-line fluorescent derivatization and detection coupled to LIF. - Highlights: • A highly selective and sensitive derivatizing reagent for Cr(III) was synthesized and characterized. • The magnetic-MWCNTs nanocomposite as a SPE sorbent was successfully synthesized and characterized. • A new portable detection system was developed for microfluidic chip FIA platform.

Characterization of electron beams generated in a high-voltage pulse-line-driven pseudospark discharge

International Nuclear Information System (INIS)

Ramaswamy, K.; Destler, W.W.; Segalov, Z.; Rodgers, J.

1994-01-01

Emittance and energy measurements have been performed on a high-brightness electron beam (>10 10 A/m 2 rad 2 ) with diameter in the range 1--3 mm and energy in the range 150--170 keV. This electron beam is generated by the mating of a hollow-cathode discharge device operating in the pseudospark regime to the output of a high-power pulse line accelerator. The measured effective emittance lies in the range between 30 and 90 mm mrad and increases with axial distance. Electron energy measurements indicate that the high-energy electrons are generated during the first 20--30 ns of the discharge. Both the emittance and energy experiments were performed at two different ambient argon gas pressures (92 and 152 mtorr). Beam expansion as a function of axial position has also been studied and a lower bound on the beam brightness has been obtained

Low-kilovolt coherent electron diffractive imaging instrument based on a single-atom electron source

Energy Technology Data Exchange (ETDEWEB)

Lin, Chun-Yueh [Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China); Chang, Wei-Tse; Chen, Yi-Sheng; Hwu, En-Te; Chang, Chia-Seng; Hwang, Ing-Shouh, E-mail: ishwang@phys.sinica.edu.tw [Institute of Physics, Academia Sinica, Nankang, Taipei 11529, Taiwan (China); Hsu, Wei-Hao [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

2016-03-15

In this work, a transmission-type, low-kilovolt coherent electron diffractive imaging instrument was constructed. It comprised a single-atom field emitter, a triple-element electrostatic lens, a sample holder, and a retractable delay line detector to record the diffraction patterns at different positions behind the sample. It was designed to image materials thinner than 3 nm. The authors analyzed the asymmetric triple-element electrostatic lens for focusing the electron beams and achieved a focused beam spot of 87 nm on the sample plane at the electron energy of 2 kV. High-angle coherent diffraction patterns of a suspended graphene sample corresponding to (0.62 Å){sup −1} were recorded. This work demonstrated the potential of coherent diffractive imaging of thin two-dimensional materials, biological molecules, and nano-objects at a voltage between 1 and 10 kV. The ultimate goal of this instrument is to achieve atomic resolution of these materials with high contrast and little radiation damage.

Line Shape Modeling for the Diagnostic of the Electron Density in a Corona Discharge

Directory of Open Access Journals (Sweden)

Joël Rosato

2017-09-01

Full Text Available We present an analysis of spectra observed in a corona discharge designed for the study of dielectrics in electrical engineering. The medium is a gas of helium and the discharge was performed at the vicinity of a tip electrode under high voltage. The shape of helium lines is dominated by the Stark broadening due to the plasma microfield. Using a computer simulation method, we examine the sensitivity of the He 492 nm line shape to the electron density. Our results indicate the possibility of a density diagnostic based on passive spectroscopy. The influence of collisional broadening due to interactions between the emitters and neutrals is discussed.

Electronic-nose technology using sputum samples in diagnosis of patients with tuberculosis

NARCIS (Netherlands)

Kolk, A.; Hoelscher, M.; Maboko, L.; Jung, J.; Kuijper, S.; Cauchi, M.; Bessant, C.; van Beers, S.; Dutta, R.; Gibson, T.; Reither, K.

2010-01-01

We investigated the potential of two different electronic noses (EN; code named "Rob" and "Walter") to differentiate between sputum headspace samples from tuberculosis (TB) patients and non-TB patients. Only samples from Ziehl-Neelsen stain (ZN)- and Mycobacterium tuberculosis culture-positive

Auger electron spectroscopy studies of boron carbide

International Nuclear Information System (INIS)

Madden, H.H.; Nelson, G.C.; Wallace, W.O.

1986-01-01

Auger electron spectroscopy has been used to probe the electronic structure of ion bombardment (IB) cleaned surfaces of B 9 C and B 4 C samples. The shapes of the B-KVV and C-KVV Auger lines were found to be relatively insensitive to the bulk stoichiometry of the samples. This indicates that the local chemical environments surrounding B and C atoms, respectively, on the surfaces of the IB cleaned samples do not change appreciably in going from B 9 C to B 4 C. Fracturing the sample in situ is a way of producing a clean representative internal surface to compare with the IB surfaces. Microbeam techniques have been used to study a fracture surface of the B 9 C material with greater spatial resolution than in our studies of IB surfaces. The B 9 C fracture surface was not homogeneous and contained both C-rich and B-rich regions. The C-KVV line for the C-rich regions was graphitic in shape. Much of the C-rich regions was found by IB to be less than 100 nm in thickness. The C-KVV line from the B-rich regions was carbidic and did not differ appreciably in shape from those recorded for the IB cleaned surfaces

Mid-IR Properties of an Unbiased AGN Sample of the Local Universe. 1; Emission-Line Diagnostics

Science.gov (United States)

Weaver, K. A.; Melendez, M.; Muhotzky, R. F.; Kraemer, S.; Engle, K.; Malumuth. E.; Tueller, J.; Markwardt, C.; Berghea, C. T.; Dudik, R. P.;

The Size of Narrow Line Region and [OIII] Luminosity Analyzed from ...

Indian Academy of Sciences (India)

Abstract. In this work, we constructed a sample of 4002 quasars from. SDSS DR7 quasar catalogue to calculate the electron density and size of narrow line region. We find that the electron densities are ∼103/cm3, and the sizes are between 27 and 775 pc. We also find that, in the ionization cone, the sizes are tightly ...

Contrast of HOLZ lines in energy-filtered convergent-beam electron diffraction patterns from silicon

International Nuclear Information System (INIS)

Lehmpfuhl, G.; Krahl, D.; Uchida, Y.

1995-01-01

Higher-order Laue-zone (HOLZ) lines were investigated in convergent-beam electron diffraction patterns from silicon near the low-indexed zone axes [100], [110] and [111]. The visibility of these lines depends on the effective structure potentials of the reflections from the first Laue zone depending on their Debye-Waller factor. The contrast of the HOLZ lines is strongly reduced by inelastically scattered electrons. They can be excluded by an imaging Ω filter for energy losses above 2 eV. The diffraction patterns were compared with many-beam calculations. Without absorption, an excellent agreement could be achieved for the [111] and [100] zone axes, while the simulation of the [110] zone-axis pattern needed a calculation with absorption. The reason for this observation is explained in the Bloch-wave picture. Calculations with absorption, however, lead to artefacts in the intensity distribution of the [100] HOLZ pattern. In order to obtain agreement with the experiment, the Debye-Waller factor had to be modified in different ways for the different zone axes. This corresponds to a strong anisotropy of the Debye-Waller factor. To confirm this observation, the temperature dependence of the itensity distributions of the HOLZ patterns was investigated between 50 and 680 K. At room temperature, the parameter D in the Debye-Waller factor exp(-Ds 2 ) was determined as 0.13, 0.26 and 0.55 A 2 for the zone axes [100], [111] and [110], respectively. The reliability of the conclusions is discussed. (orig.)

Quantification of multielement-multilayer-samples in electron probe analysis

International Nuclear Information System (INIS)

Pfeiffer, A.

1995-03-01

The following dissertation presents the theoretical basis of analytical correction models and Monte Carlo simulations in the field of electron probe microanalysis to describe the excitation conditions of x-rays in a multilayer-multielement-sample. In this connection analyzing programs have been developed to make a quantitative investigation of heterogeneous samples possible. In the work the mathematical methods and formulas, which are mainly based on empirical and semiempirical findings, are described and their validity is discussed in detail. Especially the improvements of the 'multiple reflections'-model by August are compared with the Φ(ρz)-models by Pouchou, Merlet and Bastin. The calculations of depth distribution functions for characteristics and continuous fluorescence excitation result in a consistent and completeΦ(ρz)-model. This allows to analyze layered structures in great detail. Because of the increasing importance in electron probe microanalysis and as a reference method a Monte Carlo model is described. With this model electron trajectories and excitation conditions in arbitrary two dimensional geometries can be calculated. The validity of the analytical model is proven with a comprehensive comparison of results of new calculations to published data. To show an application of the programs and models in routine use in the industrial research and development, a quantitative analysis of a Co/Si system is made. In the conclusion of this dissertation some reflections upon investigations, which are based on this work and which should be made in future are outlined. (author)

submitter Parametric study of transport beam lines for electron beams accelerated by laser-plasma interaction

CERN Document Server

Scisciò, M; Migliorati, M; Mostacci, A; Palumbo, L; Papaphilippou, Y; Antici, P

2016-01-01

In the last decade, laser-plasma acceleration of high-energy electrons has attracted strong attention in different fields. Electrons with maximum energies in the GeV range can be laser-accelerated within a few cm using multi-hundreds terawatt (TW) lasers, yielding to very high beam currents at the source (electron bunches with up to tens-hundreds of pC in a few fs). While initially the challenge was to increase the maximum achievable electron energy, today strong effort is put in the control and usability of these laser-generated beams that still lack of some features in order to be used for applications where currently conventional, radio-frequency (RF) based, electron beam lines represent the most common and efficient solution. Several improvements have been suggested for this purpose, some of them acting directly on the plasma source, some using beam shaping tools located downstream. Concerning the latter, several studies have suggested the use of conventional accelerator magnetic devices (such as quadrupo...

Automated analysis of heterogeneous carbon nanostructures by high-resolution electron microscopy and on-line image processing

International Nuclear Information System (INIS)

Toth, P.; Farrer, J.K.; Palotas, A.B.; Lighty, J.S.; Eddings, E.G.

2013-01-01

High-resolution electron microscopy is an efficient tool for characterizing heterogeneous nanostructures; however, currently the analysis is a laborious and time-consuming manual process. In order to be able to accurately and robustly quantify heterostructures, one must obtain a statistically high number of micrographs showing images of the appropriate sub-structures. The second step of analysis is usually the application of digital image processing techniques in order to extract meaningful structural descriptors from the acquired images. In this paper it will be shown that by applying on-line image processing and basic machine vision algorithms, it is possible to fully automate the image acquisition step; therefore, the number of acquired images in a given time can be increased drastically without the need for additional human labor. The proposed automation technique works by computing fields of structural descriptors in situ and thus outputs sets of the desired structural descriptors in real-time. The merits of the method are demonstrated by using combustion-generated black carbon samples. - Highlights: ► The HRTEM analysis of heterogeneous nanostructures is a tedious manual process. ► Automatic HRTEM image acquisition and analysis can improve data quantity and quality. ► We propose a method based on on-line image analysis for the automation of HRTEM image acquisition. ► The proposed method is demonstrated using HRTEM images of soot particles

On-line monitoring of food fermentation processes using electronic noses and electronic tongues: A review

International Nuclear Information System (INIS)

Peris, Miguel; Escuder-Gilabert, Laura

2013-01-01

Graphical abstract: -- Highlights: •This review paper deals with the applications of electronic noses and electronic tongues to the monitoring of fermentation processes. •Positive and negative aspects of the different approaches reviewed are analyzed. •Current and future endeavors in this field are also commented. -- Abstract: Fermentation processes are often sensitive to even slight changes of conditions that may result in unacceptable end-product quality. Thus, close follow-up of this type of processes is critical for detecting unfavorable deviations as early as possible in order to save downtime, materials and resources. Nevertheless the use of traditional analytical techniques is often hindered by the need for expensive instrumentation and experienced operators and complex sample preparation. In this sense, one of the most promising ways of developing rapid and relatively inexpensive methods for quality control in fermentation processes is the use of chemical multisensor systems. In this work we present an overview of the most important contributions dealing with the monitoring of fermentation processes using electronic noses and electronic tongues. After a brief description of the fundamentals of both types of devices, the different approaches are critically commented, their strengths and weaknesses being highlighted. Finally, future trends in this field are also mentioned in the last section of the article

On-line monitoring of food fermentation processes using electronic noses and electronic tongues: A review

Energy Technology Data Exchange (ETDEWEB)

Peris, Miguel, E-mail: mperist@qim.upv.es [Departamento de Química, Universidad Politécnica de Valencia, 46071 Valencia (Spain); Escuder-Gilabert, Laura [Departamento de Química Analítica, Universitat de Valencia, C/ Vicente Andrés Estellés s/n, E-46100 Burjasot, Valencia (Spain)

2013-12-04

Graphical abstract: -- Highlights: •This review paper deals with the applications of electronic noses and electronic tongues to the monitoring of fermentation processes. •Positive and negative aspects of the different approaches reviewed are analyzed. •Current and future endeavors in this field are also commented. -- Abstract: Fermentation processes are often sensitive to even slight changes of conditions that may result in unacceptable end-product quality. Thus, close follow-up of this type of processes is critical for detecting unfavorable deviations as early as possible in order to save downtime, materials and resources. Nevertheless the use of traditional analytical techniques is often hindered by the need for expensive instrumentation and experienced operators and complex sample preparation. In this sense, one of the most promising ways of developing rapid and relatively inexpensive methods for quality control in fermentation processes is the use of chemical multisensor systems. In this work we present an overview of the most important contributions dealing with the monitoring of fermentation processes using electronic noses and electronic tongues. After a brief description of the fundamentals of both types of devices, the different approaches are critically commented, their strengths and weaknesses being highlighted. Finally, future trends in this field are also mentioned in the last section of the article.

Sample size effect on the determination of the irreversibility line of high-Tc superconductors

International Nuclear Information System (INIS)

Li, Q.; Suenaga, M.; Li, Q.; Freltoft, T.

1994-01-01

The irreversibility lines of a high-J c superconducting Bi 2 Sr 2 Ca 2 Cu 3 O x /Ag tape were systematically measured upon a sequence of subdivisions of the sample. The irreversibility field H r (T) (parallel to the c axis) was found to change approximately as L 0.13 , where L is the effective dimension of the superconducting tape. Furthermore, it was found that the irreversibility line for a grain-aligned Bi 2 Sr 2 Ca 2 Cu 3 O x specimen can be approximately reproduced by the extrapolation of this relation down to a grain size of a few tens of micrometers. The observed size effect could significantly obscure the real physical meaning of the irreversibility lines. In addition, this finding surprisingly indicated that the Bi 2 Sr 2 Ca 2 Cu 2 O x /Ag tape and grain-aligned specimen may have similar flux line pinning strength

Deciphering the Correlation between Breast Tumor Samples and Cell Lines by Integrating Copy Number Changes and Gene Expression Profiles

Directory of Open Access Journals (Sweden)

Yi Sun

2015-01-01

Full Text Available Breast cancer is one of the most common cancers with high incident rate and high mortality rate worldwide. Although different breast cancer cell lines were widely used in laboratory investigations, accumulated evidences have indicated that genomic differences exist between cancer cell lines and tissue samples in the past decades. The abundant molecular profiles of cancer cell lines and tumor samples deposited in the Cancer Cell Line Encyclopedia and The Cancer Genome Atlas now allow a systematical comparison of the breast cancer cell lines with breast tumors. We depicted the genomic characteristics of breast primary tumors based on the copy number variation and gene expression profiles and the breast cancer cell lines were compared to different subgroups of breast tumors. We identified that some of the breast cancer cell lines show high correlation with the tumor group that agrees with previous knowledge, while a big part of them do not, including the most used MCF7, MDA-MB-231, and T-47D. We presented a computational framework to identify cell lines that mostly resemble a certain tumor group for the breast tumor study. Our investigation presents a useful guide to bridge the gap between cell lines and tumors and helps to select the most suitable cell line models for personalized cancer studies.

Validation of a Sampling Method to Collect Exposure Data for Central-Line-Associated Bloodstream Infections.

Science.gov (United States)

Hammami, Naïma; Mertens, Karl; Overholser, Rosanna; Goetghebeur, Els; Catry, Boudewijn; Lambert, Marie-Laurence

2016-05-01

Surveillance of central-line-associated bloodstream infections requires the labor-intensive counting of central-line days (CLDs). This workload could be reduced by sampling. Our objective was to evaluate the accuracy of various sampling strategies in the estimation of CLDs in intensive care units (ICUs) and to establish a set of rules to identify optimal sampling strategies depending on ICU characteristics. Analyses of existing data collected according to the European protocol for patient-based surveillance of ICU-acquired infections in Belgium between 2004 and 2012. CLD data were reported by 56 ICUs in 39 hospitals during 364 trimesters. We compared estimated CLD data obtained from weekly and monthly sampling schemes with the observed exhaustive CLD data over the trimester by assessing the CLD percentage error (ie, observed CLDs - estimated CLDs/observed CLDs). We identified predictors of improved accuracy using linear mixed models. When sampling once per week or 3 times per month, 80% of ICU trimesters had a CLD percentage error within 10%. When sampling twice per week, this was >90% of ICU trimesters. Sampling on Tuesdays provided the best estimations. In the linear mixed model, the observed CLD count was the best predictor for a smaller percentage error. The following sampling strategies provided an estimate within 10% of the actual CLD for 97% of the ICU trimesters with 90% confidence: 3 times per month in an ICU with >650 CLDs per trimester or each Tuesday in an ICU with >480 CLDs per trimester. Sampling of CLDs provides an acceptable alternative to daily collection of CLD data.

The tension adjuster used at the work line of electron beam radiation cross-linking wire and cable

International Nuclear Information System (INIS)

Zhang Yingfa; Liu Zhenhao; Yin Xuejun

1999-01-01

The tension adjuster is an important equipment in the transport system at the work line of electron beam radiation cross-linking wire and cable to realize the velocity synchronism. There are many kinds of the adjuster. By putting various adjusters together properly, the authors can keep the line work stable and raise the quality of the product. Two kinds of standing adjuster and their mechanism are introduced. Also the corresponding figures and formulas are shown

On-line immunoaffinity column-liquid chromatography-tandem mass spectrometry method for trace analysis of diuron in wastewater treatment plant effluent sample.

Science.gov (United States)

Zhang, Xiuli; Martens, Dieter; Krämer, Petra M; Kettrup, Antonius A; Liang, Xinmiao

2006-11-10

An on-line immunoaffinity column with liquid chromatography/tandem mass spectrometry (IAC-LC-MS/MS) method for the determination of diuron in water matrices was described. This method used a sol-gel immunoaffinity column (20 mm x 4 mm I.D.) for on-line sample cleanup and enrichment, a monolithic analytical column (100 mm x 4.6 mm I.D.) for separation, and a triple quadrupole mass spectrometer for quantitation. The major challenges for the on-line set-up were discussed. The optimized on-line protocol was emphasized by the fact that low limit of quantitation (LOQ) of 1.0 ng/L was achieved with only 2.5-mL sample. In addition, a satisfactory accuracy ( approximately 90% of recovery) and precision (effect, the on-line IAC-LC-MS/MS analysis method can reliably determine diuron in wastewater treatment plant effluent sample.

Shape of electron lines emitted by a fast particle in atomic collisions. Influence of the acceptance function

International Nuclear Information System (INIS)

Bordenave-Montesquieu, A.; Gleizes, A.; Benoit-Cattin, P.; Boudjema, M.

1980-01-01

In order to explain the large energy broadening of the lines observed in energy spectra of electrons emitted by fast particles, an accurate knowledge of the angular acceptance function of the electron energy analyser is necessary. A simple method is proposed which can give an accurate function for most atomic collisions: the various approximations are discussed. It is also shown that the analyser transmission depends on the acceptance angle. (author)

Relative humidity effects on water vapour fluxes measured with closed-path eddy-covariance systems with short sampling lines

DEFF Research Database (Denmark)

Fratini, Gerardo; Ibrom, Andreas; Arriga, Nicola

2012-01-01

It has been formerly recognised that increasing relative humidity in the sampling line of closed-path eddy-covariance systems leads to increasing attenuation of water vapour turbulent fluctuations, resulting in strong latent heat flux losses. This occurrence has been analyzed for very long (50 m...... from eddy-covariance systems featuring short (4 m) and very short (1 m) sampling lines running at the same clover field and show that relative humidity effects persist also for these setups, and should not be neglected. Starting from the work of Ibrom and co-workers, we propose a mixed method...... and correction method proposed here is deemed applicable to closed-path systems featuring a broad range of sampling lines, and indeed applicable also to passive gases as a special case. The methods described in this paper are incorporated, as processing options, in the free and open-source eddy...

Very low-energy conversion electron detection (VLECED) system at the isocele on-line isotope separator, Orsay

International Nuclear Information System (INIS)

Kilcher, P.; Sauvage, J.; Munsch, J.; Obert, J.; Caruette, A.; Ferro, A.; Boissier, G.; Fournet-Fayas, J.; Ducourtieux, M.; Landois, G.

1988-01-01

A system designed and installed at the on-line isotope separator ISOCELE II allows the high resolution detection of low-energy conversion electrons (down to 1 keV) emitted by mass separated radioactive sources: the use of a special tape transport permits both the slowing down of the incoming beam of radioactive ions up to a collection point and the acceleration of the electrons emitted by the collected sources brought to a flat magnetic spectrograph. Typical spectra so obtained are presented

Secondary Electron Yield Measurements and Groove Chambers Tests in the PEP-II Beam Line Straights Sections

International Nuclear Information System (INIS)

Pivi, M

2008-01-01

Beam instability caused by the electron cloud has been observed in positron and proton storage rings and it is expected to be a limiting factor in the performance of the positron Damping Ring (DR) of future Linear Colliders such as ILC and CLIC [1, 2]. In the Positron Low Energy Ring (LER) of the PEP-II accelerator, we have installed vacuum chambers with rectangular grooves in a straight magnetic-free section to test this promising possible electron cloud mitigation technique. We have also installed a special chamber to monitor the secondary electron yield of TiN and TiZrV (NEG) coating, Copper, Stainless Steel and Aluminum under the effect of electron and photon conditioning in situ in the beam line. In this paper, we describe the ongoing R and D effort to mitigate the electron cloud effect for the ILC damping ring, the latest results on in situ secondary electron yield conditioning and recent update on the groove tests in PEP-II

Plasma core electron density and temperature measurements using CVI line emissions in TCABR Tokamak

Energy Technology Data Exchange (ETDEWEB)

Nascimento, F. do, E-mail: fellypen@ifi.unicamp.br [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Centro de Componentes Semicondutores; Machida, M. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Instituto de Fisica Gleb Wataghin; Severo, J.H.F.; Sanada, E.; Ronchi, G. [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

2015-08-15

In this work, we present results of electron temperature (T{sub e} ) and density (n {sub e} ) measurements obtained in Tokamak Chauffage Alfven Bresilien (TCABR) tokamak using visible spectroscopy from CVI line emissions which occurs mainly near the center of the plasma column. The presented method is based on a well-known relationship between the particle flux (Γ {sub ion}) and the photon flux (ø {sub ion}) emitted by an ion species combined with ionizations per photon atomic data provided by the atomic data and analysis structure (ADAS) database. In the experiment, we measured the photon fluxes of three different CVI spectral line emissions, 4685.2, 5290.5, and 6200.6 Å (one line per shot). Using this method it was possible to find out the temporal evolution of T{sub e} and n{sub e} in the plasma. The results achieved are in good agreement with T{sub e} and n{sub e} measurements made using other diagnostic tools. (author)

On-line control system for electron injector based on autoemission cathode

International Nuclear Information System (INIS)

Egorov, N.V.; Karpov, A.G.; Ovsyannikov, D.A.; Prudnikov, A.P.

1987-01-01

An original on-line system of control of electron injector parameters on the base of an autoemission cathode is described. The system includes hardware (analog-to-digital and graphical displays, a printer, a magnetic disc memory a plotter) and data control and readout equipment. A high-voltage power source of the 'RACE' is controlled by digital measuring devices connected with a computer data via a special matching device. Software includes servicing subroutines for injector controls and those permitting to display, plot and print results. The main operating program functioning in the interactive mode enables to specify the injector operating conditions and check its characteristics

Influence of Plastic Deformation of Steel Samples on the Fast electron Backscattering

International Nuclear Information System (INIS)

Sierra Trujillo, J. X.; Herrera Palma, V.; Desdin Garcia, L. F.; Codorniu Pujals, D.

2013-01-01

A considerable fraction of a fast electron beam incident on a target is scattered in backward direction. It is a very complex process involving electron - nucleus and electron - electron collisions. The fraction of backscattered electrons is described by a parameterization as a function of the atomic number and energy of the incident electrons. In such approaches the possible influence of the material structure is not taken into account. In this paper, the behavior of the 90 Sr/ 90 Y backscattered electrons from 08JuA and 15GJuT steel strained samples is investigated. A clear dependence between the degree of plastic deformation and the fraction of backscattered electrons was observed. This relationship is explained by the interaction of electrons with the dislocations in the material, whose density depends on the magnitude of the strain in the plastic region. On the basis of a simple model for describing this interaction, a mathematical expression is obtained for the relationship between the fraction of backscattered electrons and the degree of deformation. (Author)

NEW STRONG-LINE ABUNDANCE DIAGNOSTICS FOR H II REGIONS: EFFECTS OF κ-DISTRIBUTED ELECTRON ENERGIES AND NEW ATOMIC DATA

Energy Technology Data Exchange (ETDEWEB)

Dopita, Michael A.; Sutherland, Ralph S.; Nicholls, David C.; Kewley, Lisa J.; Vogt, Frédéric P. A., E-mail: Michael.Dopita@anu.edu.au [Research School of Astronomy and Astrophysics, Australian National University, Cotter Rd., Weston ACT 2611 (Australia)

2013-09-01

Recently, Nicholls et al., inspired by in situ observations of solar system astrophysical plasmas, suggested that the electrons in H II regions are characterized by a κ-distribution of energies rather than a simple Maxwell-Boltzmann distribution. Here, we have collected together new atomic data within a modified photoionization code to explore the effects of both the new atomic data and the κ-distribution on the strong-line techniques used to determine chemical abundances in H II regions. By comparing the recombination temperatures (T {sub rec}) with the forbidden line temperatures (T {sub FL}), we conclude that κ ∼ 20. While representing only a mild deviation from equilibrium, this result is sufficient to strongly influence abundances determined using methods that depend on measurements of the electron temperature from forbidden lines. We present a number of new emission line ratio diagnostics that cleanly separate the two parameters determining the optical spectrum of H II regions—the ionization parameter q or U and the chemical abundance, 12+log(O/H). An automated code to extract these parameters is presented. Using the homogeneous data set from van Zee et al., we find self-consistent results between all of these different diagnostics. The systematic errors between different line ratio diagnostics are much smaller than those found in the earlier strong-line work. Overall, the effect of the κ-distribution on the strong-line abundances derived solely on the basis of theoretical models is rather small.

A system for on-line monitoring of light element concentration distributions in thin samples

NARCIS (Netherlands)

Brands, P.J.M.; Mutsaers, P.H.A.; Voigt, de M.J.A.

1999-01-01

At the Cyclotron Laboratory, a scanning proton microprobe is used to determine concentration distributions in biomedical samples. The data acquired in these measurements used to be analysed in a time consuming off-line analysis. To avoid the loss of valuable measurement and analysis time, DYANA was

An on-line Integrated Bookkeeping: electronic run log book and Meta-Data Repository for ATLAS

CERN Document Server

Barczyc, M.; Caprini, M.; Da Silva Conceicao, J.; Dobson, M.; Flammer, J.; Burckhart-Chromek, D.; Caprini, M.; Conceicao, J.D.S.; Dobson, M.; Flammer, J.; Jones, R.; Kazarov, A.; Kolos, S.; Kazarov, A.; Kolos, S.; Liko, D.; Mapelli, L.; Soloviev, I.; Hart, R.; Amorim, A.; Mapelli, L.; Soloviev, I.; Amorim, A.; Klose, D.; Lima, J.; Lucio, L.; Pedro, L.; Wolters, H.; Badescu, E.; Alexandrov, I.; Kotov, V.; Mineev, M.; Ryabov, Yu.

2003-01-01

In the context of the ATLAS experiment there is growing evidence of the importance of different kinds of Meta-data including all the important details of the detector and data acquisition that are vital for the analysis of the acquired data. The Online BookKeeper (OBK) is a component of ATLAS online software that stores all information collected while running the experiment, including the Meta-data associated with the event acquisition, triggering and storage. The facilities for acquisition of control data within the on-line software framework, together with a full functional Web interface, make the OBK a powerful tool containing all information needed for event analysis, including an electronic log book. In this paper we explain how OBK plays a role as one of the main collectors and managers of Meta-data produced on-line, and we'll also focus on the Web facilities already available. The usage of the web interface as an electronic run logbook is also explained, together with the future extensions. We describe...

First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of $^{163}$Ho

CERN Document Server

Ranitzsch, P. C. -O.; Wegner, M.; Kempf, S.; Fleischmann, A.; Enss, C.; Gastaldo, L.; Herlert, A.; Johnston, K.

2014-01-01

The isotope $^{163}$Ho undergoes an electron capture process with a recommended value for the energy available to the decay, $Q_{\\rm EC}$, of about 2.5 keV. According to the present knowledge, this is the lowest $Q_{\\rm EC}$ value for electron capture processes. Because of that, $^{163}$Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the $^{163}$Dy daughter atom upon the capture of an electron from the 5s shell in $^{163}$Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the $^{163}$Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of $^{163}$Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we dis...

Observation of O+ (4P-4D0 lines in electron aurora over Svalbard

Directory of Open Access Journals (Sweden)

K. Throp

2004-09-01

Full Text Available This work reports on observations of O+ lines in aurora over Svalbard, Norway. The Spectrographic Imaging Facility measures auroral spectra in three wavelength intervals (Hβ, N+2 1N(0,2 and N+2 1N(1,3. The oxygen ion multiplet (4639-4696Å is blended with the band. It is found that in electron aurora, the brightness of this multiplet, is on average, about 0.1 of the total brightness. A joint optical and incoherent scatter radar study of an electron aurora event shows that the ratio is enhanced when the ionisation in the upper E-layer (140-190km is significant with respect to the E-layer peak below 130km. Rayed arcs were observed on one such occasion, whereas on other occasions the auroral intensity was below the threshold of the imager. A one-dimensional electron transport model is used to estimate the cross section for production of the multiplet in electron collisions, yielding 0.18x10-18cm2.

Comparison of Electron Imaging Modes for Dimensional Measurements in the Scanning Electron Microscope.

Science.gov (United States)

Postek, Michael T; Vladár, András E; Villarrubia, John S; Muto, Atsushi

2016-08-01

Dimensional measurements from secondary electron (SE) images were compared with those from backscattered electron (BSE) and low-loss electron (LLE) images. With the commonly used 50% threshold criterion, the lines consistently appeared larger in the SE images. As the images were acquired simultaneously by an instrument with the capability to operate detectors for both signals at the same time, the differences cannot be explained by the assumption that contamination or drift between images affected the SE, BSE, or LLE images differently. Simulations with JMONSEL, an electron microscope simulator, indicate that the nanometer-scale differences observed on this sample can be explained by the different convolution effects of a beam with finite size on signals with different symmetry (the SE signal's characteristic peak versus the BSE or LLE signal's characteristic step). This effect is too small to explain the >100 nm discrepancies that were observed in earlier work on different samples. Additional modeling indicates that those discrepancies can be explained by the much larger sidewall angles of the earlier samples, coupled with the different response of SE versus BSE/LLE profiles to such wall angles.

The Tynode: A new vacuum electron multiplier

Energy Technology Data Exchange (ETDEWEB)

Graaf, Harry van der, E-mail: vdgraaf@nikhef.nl [Delft University of Technology, Delft (Netherlands); Nikhef, Science Park 105, 1098 XG Amsterdam (Netherlands); Akhtar, Hassan; Budko, Neil; Chan, Hong Wah; Hagen, Cornelis W. [Delft University of Technology, Delft (Netherlands); Hansson, Conny C.T. [Delft University of Technology, Delft (Netherlands); Nikhef, Science Park 105, 1098 XG Amsterdam (Netherlands); Nützel, Gert; Pinto, Serge D. [Photonis, Roden (Netherlands); Prodanović, Violeta; Raftari, Behrouz; Sarro, Pasqualina M. [Delft University of Technology, Delft (Netherlands); Sinsheimer, John; Smedley, John [Brookhaven National Laboratory, Upton, NY 11973 (United States); Tao, Shuxia [Eindhoven University of Technology/DIFFER (Netherlands); Theulings, Anne M.M.G. [Delft University of Technology, Delft (Netherlands); Nikhef, Science Park 105, 1098 XG Amsterdam (Netherlands); Vuik, Kees [Delft University of Technology, Delft (Netherlands)

2017-03-01

By placing, in vacuum, a stack of transmission dynodes (tynodes) on top of a CMOS pixel chip, a single free electron detector could be made with outstanding performance in terms of spatial and time resolution. The essential object is the tynode: an ultra thin membrane, which emits, at the impact of an energetic electron on one side, a multiple of electrons at the other side. The electron yields of tynodes have been calculated by means of GEANT-4 Monte Carlo simulations, applying special low-energy extensions. The results are in line with another simulation based on a continuous charge-diffusion model. By means of Micro Electro Mechanical System (MEMS) technology, tynodes and test samples have been realized. The secondary electron yield of several samples has been measured in three different setups. Finally, several possibilities to improve the yield are presented.

Electron densities in planetary nebulae

International Nuclear Information System (INIS)

Stanghellini, L.; Kaler, J.B.

1989-01-01

Electron densities for 146 planetary nebulae have been obtained for analyzing a large sample of forbidden lines by interpolating theoretical curves obtained from solutions of the five-level atoms using up-to-date collision strengths and transition probabilities. Electron temperatures were derived from forbidden N II and/or forbidden O III lines or were estimated from the He II 4686 A line strengths. The forbidden O II densities are generally lower than those from forbidden Cl III by an average factor of 0.65. For data sets in which forbidden O II and forbidden S II were observed in common, the forbidden O II values drop to 0.84 that of the forbidden S II, implying that the outermost parts of the nebulae might have elevated densities. The forbidden Cl II and forbidden Ar IV densities show the best correlation, especially where they have been obtained from common data sets. The data give results within 30 percent of one another, assuming homogeneous nebulae. 106 refs

Hidden Broad Line Seyfert 2 Galaxies in the CfA and 12micron Samples

OpenAIRE

Tran, Hien D.

2001-01-01

We report the results of a spectropolarimetric survey of the CfA and 12micron samples of Seyfert 2 galaxies (S2s). Polarized (hidden) broad line regions (HBLRs) are confirmed in a number of galaxies, and several new cases (F02581-1136, MCG -3-58-7, NGC 5995, NGC 6552, NGC 7682) are reported. The 12micron S2 sample shows a significantly higher incidence of HBLR (50%) than its CfA counterpart (30%), suggesting that the latter may be incomplete in hidden AGNs. Compared to the non-HBLR S2s, the H...

Line ratios and wavelengths of helium-like argon n=2 satellite transitions and resonance lines

International Nuclear Information System (INIS)

Biedermann, C.; Radtke, R.; Fournier, K.

2003-01-01

The characteristic X-ray emission from helium-like argon was investigated as a mean to diagnose hot plasmas. We have measured the radiation from n=2-1 parent lines and from KLn dielectronic recombination satellites with high wavelength resolution as function of the excitation energy using the Berlin Electron Beam Ion Trap. Values of wavelength relative to the resonance and forbidden line are tabulated and compared with references. The line intensity observed over a wide range of excitation energies is weighted with a Maxwellian electron-energy distribution to analyze line ratios as function of plasma temperature. Line ratios (j+z)/w and k/w compare nicely with theoretical predictions and demonstrate their applicability as temperature diagnostic. The ratio z/(x+y) shows not to depend on the electron density

Quantitation of tetrabromobisphenol-A from dust sampled on consumer electronics by dispersed liquid-liquid microextraction

International Nuclear Information System (INIS)

Di Napoli-Davis, Gina; Owens, Janel E.

2013-01-01

Tetrabromobisphenol-A (TBBPA) is a brominated flame retardant used worldwide. Despite its widespread use, there are few data concerning environmental concentrations of TBBPA. Thus, the objective of this work was to optimize an ultrasound-assisted dispersed liquid-liquid microextraction (DLLME) method to analyze swabbed surfaces of consumer electronics to determine TBBPA concentrations. Upon sample preparation with DLLME, TBBPA was derivatized with acetic anhydride and then analyzed by gas chromatography–mass spectrometry (GC/MS). Using a 13 C 12 -TBBPA internal standard to improve precision and quantitation, a recovery study was performed. At concentrations of 250–1000 ng/mL, recoveries were 104–106%. Sample preparation with solid phase extraction had comparable recoveries, although overall, improved analyte recovery and precision were achieved with DLLME. In a small survey study, TBBPA concentrations in dust collected from 100 cm 2 areas on electronic surfaces (monitor, microwave, refrigerator, and TV) were determined to range from less than the LOQ to 523 ng/mL. -- Highlights: •Tetrabromobisphenol-A (TBBPA) concentrations in dust samples were determined. •Dust samples were collected from surfaces of consumer electronics. •Dispersed liquid-liquid microextraction was used to prepare samples for GC/MS. •A 13 C 12 -labeled internal standard was used to improve precision and quantitation. •TBBPA was found in dust samples at levels below LOQ to 523 ng/mL. -- This work describes the analysis of the brominated flame retardant, tetrabromobisphenol-A (TBBPA), from dust sampled on surfaces of consumer electronics

Secondary electron emission and self-consistent charge transport in semi-insulating samples

Energy Technology Data Exchange (ETDEWEB)

Fitting, H.-J. [Institute of Physics, University of Rostock, Universitaetsplatz 3, D-18051 Rostock (Germany); Touzin, M. [Unite Materiaux et Transformations, UMR CNRS 8207, Universite de Lille 1, F-59655 Villeneuve d' Ascq (France)

2011-08-15

Electron beam induced self-consistent charge transport and secondary electron emission (SEE) in insulators are described by means of an electron-hole flight-drift model (FDM) now extended by a certain intrinsic conductivity (c) and are implemented by an iterative computer simulation. Ballistic secondary electrons (SE) and holes, their attenuation to drifting charge carriers, and their recombination, trapping, and field- and temperature-dependent detrapping are included. As a main result the time dependent ''true'' secondary electron emission rate {delta}(t) released from the target material and based on ballistic electrons and the spatial distributions of currents j(x,t), charges {rho}(x,t), field F(x,t), and potential V(x,t) are obtained where V{sub 0} = V(0,t) presents the surface potential. The intrinsic electronic conductivity limits the charging process and leads to a conduction sample current to the support. In that case the steady-state total SE yield will be fixed below the unit: i.e., {sigma} {eta} + {delta} < 1.

Evaporator line for special electron tubes, in particular electron multipliers

International Nuclear Information System (INIS)

Richter, M.

1984-01-01

The invention has been aimed at reducing the effort for preventing short circuits in achieving certain material-dependent effects e.g. secondary emission, by deposition through evaporation in the production of electron tubes, in particular electron multipliers

Coincidence Doppler broadening study on hydrocarbons with pi and sigma valence electrons: positronium correction

International Nuclear Information System (INIS)

Djourelov, N.; Suzuki, T.; Yu, R.S.; Ito, Y.

2005-01-01

The coincidence Doppler broadening (CDB) technique was applied to study the electron momentum distribution in anthracene, diphenyl, naphthalene, and polystyrene. A method for separation of the positron and positronium (Ps) components from the Doppler-broadened annihilation line (DBAL) was developed further to be applicable to hydrocarbons with different π and σ valence electron distributions. This method allows extraction of the electron momentum distribution (EMD) from DBAL for samples when Ps formation occurs. The annihilation on π valence electrons was detected as broadening of the EMD compared to that obtained for a polymer sample only with σ valence electrons. The broadening appeared as a significant change in the shape of the CDB ratio of the corresponding positronium-corrected curves: a slight enhancement above the unity line in the low-momentum region and a drop in the momentum region, 10-20x10 -3 m o c

Hybridization approach to in-line and off-axis (electron) holography for superior resolution and phase sensitivity

Science.gov (United States)

Ozsoy-Keskinbora, C.; Boothroyd, C. B.; Dunin-Borkowski, R. E.; van Aken, P. A.; Koch, C. T.

2014-01-01

Holography - originally developed for correcting spherical aberration in transmission electron microscopes - is now used in a wide range of disciplines that involve the propagation of waves, including light optics, electron microscopy, acoustics and seismology. In electron microscopy, the two primary modes of holography are Gabor's original in-line setup and an off-axis approach that was developed subsequently. These two techniques are highly complementary, offering superior phase sensitivity at high and low spatial resolution, respectively. All previous investigations have focused on improving each method individually. Here, we show how the two approaches can be combined in a synergetic fashion to provide phase information with excellent sensitivity across all spatial frequencies, low noise and an efficient use of electron dose. The principle is also expected to be widely to applications of holography in light optics, X-ray optics, acoustics, ultra-sound, terahertz imaging, etc. PMID:25387480

True coincidence summing correction determination for 214Bi principal gamma lines in NORM samples

International Nuclear Information System (INIS)

Haddad, Kh.

2014-01-01

The gamma lines 609.3 and 1,120.3 keV are two of the most intensive γ emissions of 214 Bi, but they have serious true coincidence summing (TCS) effects due to the complex decay schemes with multi-cascading transitions. TCS effects cause inaccurate count rate and hence erroneous results. A simple and easy experimental method for determination of TCS correction of 214 Bi gamma lines was developed in this work using naturally occurring radioactive material samples. Height efficiency and self attenuation corrections were determined as well. The developed method has been formulated theoretically and validated experimentally. The corrections problems were solved simply with neither additional standard source nor simulation skills. (author)

Microwave-induced co-tunneling in single electron tunneling transistors

DEFF Research Database (Denmark)

Ejrnaes, M.; Savolainen, M.; Manscher, M.

2002-01-01

on rubber bellows. Cross-talk was minimized by using individual coaxial lines between the sample and the room temperature electronics: The co-tunneling experiments were performed at zero DC bias current by measuring the voltage response to a very small amplitude 2 Hz current modulation with the gate voltage......The influence of microwaves on the co-tunneling in single electron tunneling transistors has been investigated as function of frequency and power in the temperature range from 150 to 500 mK. All 20 low frequency connections and the RF line were filtered, and the whole cryostat was suspended...

On-line combination of liquid chromatography and capillary gas chromatography : preconcentration and analysis of organic compounds in aqueous samples

NARCIS (Netherlands)

Noij, T.H.M.; Weiss, E.; Herps, T.; Cruchten, van H.; Rijks, J.A.

1988-01-01

This paper describes the design of a new, versatile, and low-cost on-line LC-GC interface that allows the fast and reliable introduction of large sample volumes onto a capillary GC column. The sample introduction procedure consists successively of: evaporation of the entire sample (LC fraction),

Process and device of elementary and chemical analysis of a sample through a spectral analysis of the secondary electron energies

International Nuclear Information System (INIS)

Le Gressus, Claude; Massignon, Daniel; Sopizet, Rene.

1975-01-01

The present invention relates to a method of chemical and elementary analysis of samples through a spectral analysis of secondary electrons (Auger electrons) emitted from said sample under a primary monokinetic electron beam concentrated on its surface. Said method is characterized in that the intensity of the primary monokinetic electron beam emitted from an electron gun is modulated at a frequency ω; and in that the secondary electrons of energy E emitted from the sample are then collected. A reference voltage corresponding to the modulation in intensity of the primary electron beam is applied at the input of a phase sensitive detector together with a voltage proportional to the intensity of the flux of said collected secondary electrons to obtain at the output of said detector a voltage proportional to the number of the secondary electrons of energy E. The secondary emission energy spectrum of the sample is then plotted [fr

Acetic Acid Detection Threshold in Synthetic Wine Samples of a Portable Electronic Nose

Directory of Open Access Journals (Sweden)

Miguel Macías Macías

2012-12-01

Full Text Available Wine quality is related to its intrinsic visual, taste, or aroma characteristics and is reflected in the price paid for that wine. One of the most important wine faults is the excessive concentration of acetic acid which can cause a wine to take on vinegar aromas and reduce its varietal character. Thereby it is very important for the wine industry to have methods, like electronic noses, for real-time monitoring the excessive concentration of acetic acid in wines. However, aroma characterization of alcoholic beverages with sensor array electronic noses is a difficult challenge due to the masking effect of ethanol. In this work, in order to detect the presence of acetic acid in synthetic wine samples (aqueous ethanol solution at 10% v/v we use a detection unit which consists of a commercial electronic nose and a HSS32 auto sampler, in combination with a neural network classifier (MLP. To find the characteristic vector representative of the sample that we want to classify, first we select the sensors, and the section of the sensors response curves, where the probability of detecting the presence of acetic acid will be higher, and then we apply Principal Component Analysis (PCA such that each sensor response curve is represented by the coefficients of its first principal components. Results show that the PEN3 electronic nose is able to detect and discriminate wine samples doped with acetic acid in concentrations equal or greater than 2 g/L.

Analysis of line integrated electron density using plasma position data on Korea Superconducting Tokamak Advanced Research

International Nuclear Information System (INIS)

Nam, Y. U.; Chung, J.

2010-01-01

A 280 GHz single-channel horizontal millimeter-wave interferometer system has been installed for plasma electron density measurements on the Korea Superconducting Tokamak Advanced Research (KSTAR) device. This system has a triangular beam path that does not pass through the plasma axis due to geometrical constraints in the superconducting tokamak. The term line density on KSTAR has a different meaning from the line density of other tokamaks. To estimate the peak density and the mean density from the measured line density, information on the position of the plasma is needed. The information has been calculated from tangentially viewed visible images using the toroidal symmetry of the plasma. Interface definition language routines have been developed for this purpose. The calculated plasma position data correspond well to calculation results from magnetic analysis. With the position data and an estimated plasma profile, the peak density and the mean density have been obtained from the line density. From these results, changes of plasma density themselves can be separated from effects of the plasma movements, so they can give valuable information on the plasma status.

Sample acceptance time criteria, electronic issue and alloimmunisation in thalassaemia.

Science.gov (United States)

Trompeter, S; Baxter, L; McBrearty, M; Zatkya, E; Porter, J

2015-12-01

To determine the safety of a 1-week acceptance criteria of sample receipt in laboratory to transfusion commencement in transfusion dependent thalassaemia with respect to alloimmunisation. To determine the safety of electronic issue of blood components in such a setting. Retrospective audit of alloimmunisation (1999-2012) and blood exposure in registered thalassaemia patients at a central London thalassaemia centre where the acceptance criteria for the group and save sample from arrival in the laboratory to the time of issue of blood for transfusion for someone who has been transfused in the last 28 days was 1 week, and there was electronic issue protocol for patients who have always had a negative antibody screen (other than temporary positivity in pregnant women receiving prophylactic anti-D or anti Le-a, Anti Le-b and Anti P1 that are no longer detectable). There were 133 patients with thalassemia variants regularly attending UCLH for review. A total of 105 patients had transfusion dependent thalassaemia (TDT) (7 E-beta thalassaemia, 98 beta thalassaemia major). Ten of the 84 patients who received their transfusions at UCLH were alloimmunised. Seven of them had been alloimmunised prior to arrival at UCLH. Only two patients developed antibodies at UCLH during this period. The prevalence of alloantibody formation of 2% in UCLH transfused patients, with presumptive incidence of 0.01 alloantibodies per 100 units or 0·001 immunisations per person per year compares favourably with other reported series and suggests that 1 week interval with appropriate electronic issue is acceptable practice. © 2015 British Blood Transfusion Society.

Electronic tongue system to evaluate flavor of soybean (Glycine Max (L. Merrill genotypes

Directory of Open Access Journals (Sweden)

Sandra Maria Zoldan

2014-10-01

Full Text Available An electronic tongue system was tested as a fast and efficient analytical tool for flavor evaluation of soybean genotypes. Grain samples of 25 soybean lines were analyzed using 0.25 g of milled samples added to 100 mL of distilled water and mixing for one minute on a magnetic stirrer. An aliquot (50 mL from the filtered liquid was used for the analysis on a pre-fixed frequency of 1 kHz and alternate tension of 50 mV. Two analyses were conducted in a complete randomized design with three replicates. Electrical response (capacitance of eight polymeric chemical sensors used to analyze the soybean lines were submitted to Principal Component Analysis (PCA. In the spatial distribution of the PCA graphic, the lines close to each other were similar, while the distant ones showed different characteristics. The electronic tongue system was efficient in discriminating flavor of soybean lines.

Dynamical "in situ" observation of biological samples using variable pressure scanning electron microscope

Czech Academy of Sciences Publication Activity Database

Neděla, Vilém

2008-01-01

Roč. 126, - (2008), 012046:1-4 ISSN 1742-6588. [Electron Microscopy and Analysis Group Conference 2007 (EMAG 2007). Glasgow, 03.09.2007-07.09.2007] R&D Projects: GA ČR(CZ) GA102/05/0886; GA AV ČR KJB200650602 Institutional research plan: CEZ:AV0Z20650511 Keywords : biological sample * VP-SEM * dynamical experiments Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

Time evolution of the characteristic electron energy losses spectra of the electrons scattered on polycrystal samples of Al mechanically cleaned in vacuum

International Nuclear Information System (INIS)

Szczesny, R.; Baranowski, A.; Beliczynski, J.

1982-01-01

Measurements by the reflection technique of characteristic electron energy losses (CEEL) with a primary electron beam of energy E 0 =1 keV have been carried out on polycrystal samples of Al. The sample surfaces have been mechanically cleaned in a dinamical vacuum of the order 10 -6 Tr before each measurement. The CEEL spectra have been corrected for the resolving power of the apparatus by the deconvolution method. We have ascertained that the measuring technique and elaboration data method are useful for quickly obtaining the plasmon energy loss spectrum for an investigated material. (author)

A system for on-line monitoring of light element concentration distributions in thin samples

Energy Technology Data Exchange (ETDEWEB)

Brands, P.J.M. E-mail: p.j.m.brands@tue.nl; Mutsaers, P.H.A.; Voigt, M.J.A. de

1999-09-02

At the Cyclotron Laboratory, a scanning proton microprobe is used to determine concentration distributions in biomedical samples. The data acquired in these measurements used to be analysed in a time consuming off-line analysis. To avoid the loss of valuable measurement and analysis time, DYANA was developed. DYANA is an on-line method for the analysis of data from biomedical measurements. By using a database of background shapes, light elements such as Na and Mg, can be fitted even more precisely than in conventional fitting procedures. The entire analysis takes only several seconds and is performed while the acquisition system is gathering a new subset of data. Data acquisition must be guaranteed and may not be interfered by other parallel processes. Therefore, the analysis, the data acquisition and the experiment control is performed on a PCI-based Pentium personal computer (PC), running a real-time operating system. A second PC is added to run a graphical user interface for interaction with the experimenter and the monitoring of the analysed results. The system is here illustrated using atherosclerotic tissue but is applicable to all kinds of thin samples.

Electronic transport of bilayer graphene with asymmetry line defects

International Nuclear Information System (INIS)

Zhao Xiao-Ming; Chen Chan; Liang Ying; Kou Su-Peng; Wu Ya-Jie

2016-01-01

In this paper, we study the quantum properties of a bilayer graphene with (asymmetry) line defects. The localized states are found around the line defects. Thus, the line defects on one certain layer of the bilayer graphene can lead to an electric transport channel. By adding a bias potential along the direction of the line defects, we calculate the electric conductivity of bilayer graphene with line defects using the Landauer–Büttiker theory, and show that the channel affects the electric conductivity remarkably by comparing the results with those in a perfect bilayer graphene. This one-dimensional line electric channel has the potential to be applied in nanotechnology engineering. (paper)

Metal-poor dwarf galaxies in the SIGRID galaxy sample. II. The electron temperature-abundance calibration and the parameters that affect it

Energy Technology Data Exchange (ETDEWEB)

Nicholls, David C.; Dopita, Michael A.; Sutherland, Ralph S.; Jerjen, Helmut; Kewley, Lisa J., E-mail: David.Nicholls@anu.edu.au [Research School of Astronomy and Astrophysics, Australian National University, Cotter Rd., Weston ACT 2611 (Australia)

2014-07-20

In this paper, we use the Mappings photoionization code to explore the physical parameters that impact on the measurement of electron temperature and abundance in H II regions. In our previous paper, we presented observations and measurements of physical properties from the spectra of 17 H II regions in 14 isolated dwarf irregular galaxies from the SIGRID sample. Here, we analyze these observations further, together with three additional published data sets. We explore the effects of optical thickness, electron density, ionization parameter, ionization source, and non-equilibrium effects on the relation between electron temperature and metallicity. We present a standard model that fits the observed data remarkably well at metallicities between one-tenth and 1 solar. We investigate the effects of optically thin H II regions, and show that they can have a considerable effect on the measured electron temperature, and that there is evidence that some of the observed objects are optically thin. We look at the role of the ionization parameter and find that lower ionization parameter values give better fits at higher oxygen abundance. We show that higher pressures combined with low optical depth, and also κ electron energy distributions at low κ values, can generate the apparent high electron temperatures in low-metallicity H II regions, and that the former provides the better fit to observations. We examine the effects of these parameters on the strong line diagnostic methods. We extend this to three-dimensional diagnostic grids to confirm how well the observations are described by the grids.

Parametric study of transport beam lines for electron beams accelerated by laser-plasma interaction

Science.gov (United States)

Scisciò, M.; Lancia, L.; Migliorati, M.; Mostacci, A.; Palumbo, L.; Papaphilippou, Y.; Antici, P.

2016-03-01

In the last decade, laser-plasma acceleration of high-energy electrons has attracted strong attention in different fields. Electrons with maximum energies in the GeV range can be laser-accelerated within a few cm using multi-hundreds terawatt (TW) lasers, yielding to very high beam currents at the source (electron bunches with up to tens-hundreds of pC in a few fs). While initially the challenge was to increase the maximum achievable electron energy, today strong effort is put in the control and usability of these laser-generated beams that still lack of some features in order to be used for applications where currently conventional, radio-frequency (RF) based, electron beam lines represent the most common and efficient solution. Several improvements have been suggested for this purpose, some of them acting directly on the plasma source, some using beam shaping tools located downstream. Concerning the latter, several studies have suggested the use of conventional accelerator magnetic devices (such as quadrupoles and solenoids) as an easy implementable solution when the laser-plasma accelerated beam requires optimization. In this paper, we report on a parametric study related to the transport of electron beams accelerated by laser-plasma interaction, using conventional accelerator elements and tools. We focus on both, high energy electron beams in the GeV range, as produced on petawatt (PW) class laser systems, and on lower energy electron beams in the hundreds of MeV range, as nowadays routinely obtained on commercially available multi-hundred TW laser systems. For both scenarios, our study allows understanding what are the crucial parameters that enable laser-plasma accelerators to compete with conventional ones and allow for a beam transport. We show that suitable working points require a tradeoff-combination between low beam divergence and narrow energy spread.

A Transmission Electron Microscope Investigation of Space Weathering Effects in Hayabusa Samples

Science.gov (United States)

Keller, Lindsay P.; Berger, Eve L.

2014-01-01

The Hayabusa mission to asteroid 25143 Itokawa successfully returned the first direct samples of the regolith from the surface of an asteroid. The Hayabusa samples thus present a special opportunity to directly investigate the evolution of asteroidal surfaces, from the development of the regolith to the study of the more complex effects of space weathering. Here we describe the mineralogy, microstructure and composition of three Hayabusa mission particles using transmission electron microscope (TEM) techniques

Considerations in applying on-line IC techniques to BWR's

International Nuclear Information System (INIS)

Kaleda, R.J.

1992-01-01

Ion-Chromatography (IC) has moved from its traditional role as a laboratory analytical tool to a real time, dynamic, on-line measurement device to follow ppb and sub-ppb concentrations of deleterious impurities in nuclear power plants. Electric Power Research Institute (EPRI), individual utilities, and industry all have played significant roles in effecting the transition. This paper highlights considerations and the evolution in current on-line Ion Chromatography systems. The first applications of on-line techniques were demonstrated by General Electric (GE) under EPRI sponsorship at Rancho Seco (1980), Calvert Cliffs, and McGuire nuclear units. The primary use was for diagnostic purposes. Today the on-line IC applications have been expanded to include process control and routine plant monitoring. Current on-line IC's are innovative in design, promote operational simplicity, are modular for simplified maintenance and repair, and use field-proven components which enhance reliability. Conductivity detection with electronic or chemical suppression and spectrometric detection techniques are intermixed in applications. Remote multi-point sample systems have addressed memory effects. Early applications measured ionic species in the part per billion range. Today reliable part per trillion measurements are common for on-line systems. Current systems are meeting the challenge of EPRI guideline requirements. Today's on-line IC's, with programmed sampling systems, monitor fluid streams throughout a power plant, supplying data that can be trended, stored and retrieved easily. The on-line IC has come of age. Many technical challenges were overcome to achieve today's IC

Minimum detection limit and spatial resolution of thin-sample field-emission electron probe microanalysis

International Nuclear Information System (INIS)

Kubo, Yugo; Hamada, Kotaro; Urano, Akira

2013-01-01

The minimum detection limit and spatial resolution for a thinned semiconductor sample were determined by electron probe microanalysis (EPMA) using a Schottky field emission (FE) electron gun and wavelength dispersive X-ray spectrometry. Comparison of the FE-EPMA results with those obtained using energy dispersive X-ray spectrometry in conjunction with scanning transmission electron microscopy, confirmed that FE-EPMA is largely superior in terms of detection sensitivity. Thin-sample FE-EPMA is demonstrated as a very effective method for high resolution, high sensitivity analysis in a laboratory environment because a high probe current and high signal-to-noise ratio can be achieved. - Highlights: • Minimum detection limit and spatial resolution determined for FE-EPMA. • Detection sensitivity of FE-EPMA greatly superior to that of STEM-EDX. • Minimum detection limit and spatial resolution controllable by probe current

Automatic data acquisition and on-line analysis of trace element concentration in serum samples

International Nuclear Information System (INIS)

Lecomte, R.; Paradis, P.; Monaro, S.

1978-01-01

A completely automated system has been developed to determine the trace element concentration in biological samples by measuring charged particle induced X-rays. A CDC-3100 computer with ADC and CAMAC interface is employed to control the data collection apparatus, acquire data and perform simultaneously the analysis. The experimental set-up consists of a large square plexiglass chamber in which a commercially available 750H Kodak Carousel is suitably arranged as a computer controlled sample changer. A method of extracting trace element concentrations using reference spectra is presented and an on-line program has been developed to easily and conveniently obtain final results at the end of each run. (Auth.)

Combination of the ionic-to-atomic line intensity ratios from two test elements for the diagnostic of plasma temperature and electron number density in Inductively Coupled Plasma Atomic Emission Spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Tognoni, E. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)], E-mail: tognoni@ipcf.cnr.it; Hidalgo, M.; Canals, A. [Departamento de Quimica Analitica, Nutricion y Bromatologia. Universidad de Alicante. Apdo. 99, 03080, Alicante (Spain); Cristoforetti, G.; Legnaioli, S.; Salvetti, A.; Palleschi, V. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)

2007-05-15

In Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) spectrochemical analysis, the MgII(280.270 nm)/MgI(285.213 nm) ionic to atomic line intensity ratio is commonly used as a monitor of the robustness of operating conditions. This approach is based on the univocal relationship existing between intensity ratio and plasma temperature, for a pure argon atmospheric ICP in thermodynamic equilibrium. In a multi-elemental plasma in the lower temperature range, the measurement of the intensity ratio may not be sufficient to characterize temperature and electron density. In such a range, the correct relationship between intensity ratio and plasma temperature can be calculated only when the complete plasma composition is known. We propose the combination of the line intensity ratios of two test elements (double ratio) as an effective diagnostic tool for a multi-elemental low temperature LTE plasma of unknown composition. In particular, the variation of the double ratio allows us discriminating changes in the plasma temperature from changes in the electron density. Thus, the effects on plasma excitation and ionization possibly caused by introduction of different samples and matrices in non-robust conditions can be more accurately interpreted. The method is illustrated by the measurement of plasma temperature and electron density in a specific analytic case.

Signal enhancement of neutral He emission lines by fast electron bombardment of laser-induced He plasma

Directory of Open Access Journals (Sweden)

Hery Suyanto

2016-08-01

Full Text Available A time-resolved spectroscopic study is performed on the enhancement signals of He gas plasma emission using nanosecond (ns and picosecond (ps lasers in an orthogonal configuration. The ns laser is used for the He gas plasma generation and the ps laser is employed for the ejection of fast electrons from a metal target, which serves to excite subsequently the He atoms in the plasma. The study is focused on the most dominant He I 587.6 nm and He I 667.8 nm emission lines suggested to be responsible for the He-assisted excitation (HAE mechanism. The time-dependent intensity enhancements induced by the fast electrons generated with a series of delayed ps laser ablations are deduced from the intensity time profiles of both He emission lines. The results clearly lead to the conclusion that the metastable excited triplet He atoms are actually the species overwhelmingly produced during the recombination process in the ns laser-induced He gas plasma. These metastable He atoms are believed to serve as the major energy source for the delayed excitation of analyte atoms in ns laser-induced breakdown spectroscopy (LIBS using He ambient gas.

Signal enhancement of neutral He emission lines by fast electron bombardment of laser-induced He plasma

Energy Technology Data Exchange (ETDEWEB)

Suyanto, Hery [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Hedwig, Rinda [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, Rawamangun, Jakarta 12440 (Indonesia); Ramli, Muliadi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Lie, Tjung Jie; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Abdulmadjid, Syahrun Nur [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Tjia, May On [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha,Bandung 40132 (Indonesia); Kagawa, Kiichiro [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Fukui Science Education Academy, Takagi Chuo 2 chome, Fukui 910-0804 (Japan)

2016-08-15

A time-resolved spectroscopic study is performed on the enhancement signals of He gas plasma emission using nanosecond (ns) and picosecond (ps) lasers in an orthogonal configuration. The ns laser is used for the He gas plasma generation and the ps laser is employed for the ejection of fast electrons from a metal target, which serves to excite subsequently the He atoms in the plasma. The study is focused on the most dominant He I 587.6 nm and He I 667.8 nm emission lines suggested to be responsible for the He-assisted excitation (HAE) mechanism. The time-dependent intensity enhancements induced by the fast electrons generated with a series of delayed ps laser ablations are deduced from the intensity time profiles of both He emission lines. The results clearly lead to the conclusion that the metastable excited triplet He atoms are actually the species overwhelmingly produced during the recombination process in the ns laser-induced He gas plasma. These metastable He atoms are believed to serve as the major energy source for the delayed excitation of analyte atoms in ns laser-induced breakdown spectroscopy (LIBS) using He ambient gas.

THE CORES OF THE Fe Kα LINES IN ACTIVE GALACTIC NUCLEI: AN EXTENDED CHANDRA HIGH ENERGY GRATING SAMPLE

International Nuclear Information System (INIS)

Shu, X. W.; Wang, J. X.; Yaqoob, T.

2010-01-01

We extend the study of the core of the Fe Kα emission line at ∼6.4 keV in Seyfert galaxies reported by Yaqoob and Padmanabhan using a larger sample observed by the Chandra high-energy grating (HEG). The sample consists of 82 observations of 36 unique sources with z H 23 cm -2 ) Seyfert galaxies to date. From an empirical and uniform analysis, we present measurements of the Fe Kα line centroid energy, flux, equivalent width (EW), and intrinsic width (FWHM). The Fe Kα line is detected in 33 sources, and its centroid energy is constrained in 32 sources. In 27 sources, the statistical quality of the data is good enough to yield measurements of the FWHM. We find that the distribution in the line centroid energy is strongly peaked around the value for neutral Fe, with over 80% of the observations giving values in the range 6.38-6.43 keV. Including statistical errors, 30 out of 32 sources (∼94%) have a line centroid energy in the range 6.35-6.47 keV. The mean EW, among the observations in which a non-zero lower limit could be measured, was 53 ± 3 eV. The mean FWHM from the subsample of 27 sources was 2060 ± 230 km s -1 . The mean EW and FWHM are somewhat higher when multiple observations for a given source are averaged. From a comparison with the Hβ optical emission-line widths (or, for one source, Brα), we find that there is no universal location of the Fe Kα line-emitting region relative to the optical broad-line region (BLR). In general, a given source may have contributions to the Fe Kα line flux from parsec-scale distances from the putative black hole, down to matter a factor ∼2 closer to the black hole than the BLR. We confirm the presence of the X-ray Baldwin effect, an anti-correlation between the Fe Kα line EW and X-ray continuum luminosity. The HEG data have enabled isolation of this effect to the narrow core of the Fe Kα line.

Size characterization of airborne SiO2 nanoparticles with on-line and off-line measurement techniques: an interlaboratory comparison study

Science.gov (United States)

Motzkus, C.; Macé, T.; Gaie-Levrel, F.; Ducourtieux, S.; Delvallee, A.; Dirscherl, K.; Hodoroaba, V.-D.; Popov, I.; Popov, O.; Kuselman, I.; Takahata, K.; Ehara, K.; Ausset, P.; Maillé, M.; Michielsen, N.; Bondiguel, S.; Gensdarmes, F.; Morawska, L.; Johnson, G. R.; Faghihi, E. M.; Kim, C. S.; Kim, Y. H.; Chu, M. C.; Guardado, J. A.; Salas, A.; Capannelli, G.; Costa, C.; Bostrom, T.; Jämting, Å. K.; Lawn, M. A.; Adlem, L.; Vaslin-Reimann, S.

2013-10-01

Results of an interlaboratory comparison on size characterization of SiO2 airborne nanoparticles using on-line and off-line measurement techniques are discussed. This study was performed in the framework of Technical Working Area (TWA) 34—"Properties of Nanoparticle Populations" of the Versailles Project on Advanced Materials and Standards (VAMAS) in the project no. 3 "Techniques for characterizing size distribution of airborne nanoparticles". Two types of nano-aerosols, consisting of (1) one population of nanoparticles with a mean diameter between 30.3 and 39.0 nm and (2) two populations of non-agglomerated nanoparticles with mean diameters between, respectively, 36.2-46.6 nm and 80.2-89.8 nm, were generated for characterization measurements. Scanning mobility particle size spectrometers (SMPS) were used for on-line measurements of size distributions of the produced nano-aerosols. Transmission electron microscopy, scanning electron microscopy, and atomic force microscopy were used as off-line measurement techniques for nanoparticles characterization. Samples were deposited on appropriate supports such as grids, filters, and mica plates by electrostatic precipitation and a filtration technique using SMPS controlled generation upstream. The results of the main size distribution parameters (mean and mode diameters), obtained from several laboratories, were compared based on metrological approaches including metrological traceability, calibration, and evaluation of the measurement uncertainty. Internationally harmonized measurement procedures for airborne SiO2 nanoparticles characterization are proposed.

Size characterization of airborne SiO2 nanoparticles with on-line and off-line measurement techniques: an interlaboratory comparison study

International Nuclear Information System (INIS)

Motzkus, C.; Macé, T.; Gaie-Levrel, F.; Ducourtieux, S.; Delvallee, A.; Dirscherl, K.; Hodoroaba, V.-D.; Popov, I.; Popov, O.; Kuselman, I.; Takahata, K.; Ehara, K.; Ausset, P.; Maillé, M.; Michielsen, N.; Bondiguel, S.; Gensdarmes, F.; Morawska, L.; Johnson, G. R.; Faghihi, E. M.

2013-01-01

Results of an interlaboratory comparison on size characterization of SiO 2 airborne nanoparticles using on-line and off-line measurement techniques are discussed. This study was performed in the framework of Technical Working Area (TWA) 34—“Properties of Nanoparticle Populations” of the Versailles Project on Advanced Materials and Standards (VAMAS) in the project no. 3 “Techniques for characterizing size distribution of airborne nanoparticles”. Two types of nano-aerosols, consisting of (1) one population of nanoparticles with a mean diameter between 30.3 and 39.0 nm and (2) two populations of non-agglomerated nanoparticles with mean diameters between, respectively, 36.2–46.6 nm and 80.2–89.8 nm, were generated for characterization measurements. Scanning mobility particle size spectrometers (SMPS) were used for on-line measurements of size distributions of the produced nano-aerosols. Transmission electron microscopy, scanning electron microscopy, and atomic force microscopy were used as off-line measurement techniques for nanoparticles characterization. Samples were deposited on appropriate supports such as grids, filters, and mica plates by electrostatic precipitation and a filtration technique using SMPS controlled generation upstream. The results of the main size distribution parameters (mean and mode diameters), obtained from several laboratories, were compared based on metrological approaches including metrological traceability, calibration, and evaluation of the measurement uncertainty. Internationally harmonized measurement procedures for airborne SiO 2 nanoparticles characterization are proposed

MID-INFRARED PROPERTIES OF THE SWIFT BURST ALERT TELESCOPE ACTIVE GALACTIC NUCLEI SAMPLE OF THE LOCAL UNIVERSE. I. EMISSION-LINE DIAGNOSTICS

International Nuclear Information System (INIS)

Weaver, K. A.; Melendez, M.; Mushotzky, R. F.; Kraemer, S.; Engle, K.; Malumuth, E.; Tueller, J.; Markwardt, C.; Berghea, C. T.; Dudik, R. P.; Winter, L. M.; Armus, L.

2010-01-01

We compare mid-infrared emission-line properties from high-resolution Spitzer spectra of a hard X-ray (14-195 keV) selected sample of nearby (z < 0.05) active galactic nuclei (AGNs) detected by the Burst Alert Telescope (BAT) aboard Swift. The luminosity distribution for the mid-infrared emission lines, [O IV] 25.89 μm, [Ne II] 12.81 μm, [Ne III] 15.56 μm, and [Ne V] 14.32/24.32 μm, and hard X-ray continuum show no differences between Seyfert 1 and Seyfert 2 populations; however, six newly discovered BAT AGNs are under-luminous in [O IV], most likely the result of dust extinction in the host galaxy. The overall tightness of the mid-infrared correlations and BAT fluxes and luminosities suggests that the emission lines primarily arise in gas ionized by the AGNs. We also compare the mid-infrared emission lines in the BAT AGNs with those from published studies of ULIRGs, Palomar-Green quasars, star-forming galaxies, and LINERs. We find that the BAT AGN sample falls into a distinctive region when comparing the [Ne III]/[Ne II] and the [O IV]/[Ne III] ratios. These line ratios are lower in sources that have been previously classified in the mid-infrared/optical as AGNs than those found for the BAT AGNs, suggesting that, in our X-ray selected sample, the AGNs represent the main contribution to the observed line emission. These ratios represent a new emission line diagnostic for distinguishing between AGNs and star-forming galaxies.

Impedance of an annular-cathode indented-anode electron diode terminating a coaxial magnetically insulated transmission line

International Nuclear Information System (INIS)

Sanford, T.W.L.; Poukey, J.W.; Wright, T.P.; Bailey, J.; Heath, C.E.; Mock, R.; Spence, P.W.; Fockler, J.; Kishi, H.

1988-01-01

The impedance of a diode having an annular cathode and indented anode that terminates a coaxial MITL (magnetically insulated transmission line) is measured and compared with a semiempirical model developed from calculations made using the magIc code. The measurements were made on the 16-Ω electron accelerator HELIA (high-energy linear induction accelerator) operating at 3 MV. The model agrees with the measurements within the 10% measuring error and shows that the diode operates in either a load- or line-dominated regime depending on AK (anode-cathode) gap spacing. In the load-dominated regime, which corresponds to small AK gaps, the diode impedance is controlled by an effective anode-cathode gap, and the flow is approximately axial. In the line-dominated regime, which corresponds to large AK gaps, the impedance is independent of the AK gap and corresponds to the impedance associated with the minimum current solution of the MITL, with the flow becoming more radial as the AK gap is increased

Measurement of radioactive lines in powdered milk samples in Londrina (Parana State, Brazil) region

International Nuclear Information System (INIS)

Melquiades, Fabio Luiz

2000-01-01

This work deals with the measurement of radioactive lines in powdered milk, with high resolution gamma spectrometry, using a HPGe detector with relative efficiency of 10%, coupled to the electronic nuclear chain and a multichannel card of 8192 channels. Some tests were realized before beginning the measurements. The first of them was to define the shield to be used, making several measured with different shields according to the available materials, opting finally for a shield composed of bricks of lead (10 cm thickness), plates of iron (4nm thickness) and of aluminum (2 mm thickness). Four different geometries for the samples recipients were tested, and the Marinelli beaker of 2,1 liters totally filled was the one which supplied the best peak/background ratio. A statistical inference was also realized to determine the sampling that represents each one of the lots of milk to be measured, resulting in a number of 6 samples, for a confidence level of 95%. Two different kinds of powdered milk produced at Londrina were analyzed, Integral Powdered Milk Cativa and Integral Powdered Milk Polly. The samples were properly put in the Marinelli beaker of 2,1 L, sealed and kept for 40 days to reach the secular equilibrium. The counting time for each measurement was two days. It was possible to identify the radionuclides 40 K, 137 Cs and 232 Th (from 208 Tl), whose activities were calculated according to the International Atomic Energy Agency norms (IAEA, 1989). The detector efficiency was measured using calibrated samples, prepared with the certified reference materials IAEA-326 and IAEA-375. Corrections for self-absorption were accomplished, based on measures of samples with different densities. The results obtained for the powdered milk Cativa were: 464± 12 Bq/kg for 40 K, 3,46 ± 1,05 and 0,46 ± 1,05 and 0,46 ± 0,16 Bq/kg for the minimum detectable activities of 137 Cs and 232 Th, respectively. For the milk Polly, the results were: 452±10 Bq/kg for 40 K, 3,19 ± 0

The Kinematics of the Permitted C ii λ 6578 Line in a Large Sample of Planetary Nebulae

Energy Technology Data Exchange (ETDEWEB)

Richer, Michael G.; Suárez, Genaro; López, José Alberto; García Díaz, María Teresa, E-mail: richer@astrosen.unam.mx, E-mail: gsuarez@astro.unam.mx, E-mail: jal@astrosen.unam.mx, E-mail: tere@astro.unam.mx [Instituto de Astronomía, Universidad Nacional Autónoma de México, Ensenada, Baja California (Mexico)

2017-03-01

We present spectroscopic observations of the C ii λ 6578 permitted line for 83 lines of sight in 76 planetary nebulae at high spectral resolution, most of them obtained with the Manchester Echelle Spectrograph on the 2.1 m telescope at the Observatorio Astronómico Nacional on the Sierra San Pedro Mártir. We study the kinematics of the C ii λ 6578 permitted line with respect to other permitted and collisionally excited lines. Statistically, we find that the kinematics of the C ii λ 6578 line are not those expected if this line arises from the recombination of C{sup 2+} ions or the fluorescence of C{sup +} ions in ionization equilibrium in a chemically homogeneous nebular plasma, but instead its kinematics are those appropriate for a volume more internal than expected. The planetary nebulae in this sample have well-defined morphology and are restricted to a limited range in H α line widths (no large values) compared to their counterparts in the Milky Way bulge; both these features could be interpreted as the result of young nebular shells, an inference that is also supported by nebular modeling. Concerning the long-standing discrepancy between chemical abundances inferred from permitted and collisionally excited emission lines in photoionized nebulae, our results imply that multiple plasma components occur commonly in planetary nebulae.

Improving off-line accelerated tryptic digestion. Towards fast-lane proteolysis of complex biological samples.

Science.gov (United States)

Vukovic, Jadranka; Loftheim, Håvard; Winther, Bjørn; Reubsaet, J Léon E

2008-06-27

Off-line digestion of proteins using immobilized trypsin beads is studied with respect to the format of the digestion reactor, the digestion conditions, the comparison with in-solution digestion and its use in complex biological samples. The use of the filter vial as the most appropriate digestion reactor enables simple, efficient and easy-to-handle off-line digestion of the proteins on trypsin beads. It was shown that complex proteins like bovine serum albumin (BSA) need much longer time (89 min) and elevated temperature (37 degrees C) to be digested to an acceptable level compared to smaller proteins like cytochrome c (5 min, room temperature). Comparing the BSA digestion using immobilized trypsin beads with conventional in-solution digestion (overnight at 37 degrees C), it was shown that comparable results were obtained with respect to sequence coverage (>90%) and amount of missed cleavages (in both cases around 20 peptides with 1 or 2 missed cleavages were detected). However, the digestion using immobilized trypsin beads was considerable less time consuming. Good reproducibility and signal intensities were obtained for the digestion products of BSA in a complex urine sample. In addition to this, peptide products of proteins typically present in urine were identified.

Sample preparation methods for scanning electron microscopy of homogenized Al-Mg-Si billets: A comparative study

International Nuclear Information System (INIS)

Österreicher, Johannes Albert; Kumar, Manoj; Schiffl, Andreas; Schwarz, Sabine; Hillebrand, Daniel; Bourret, Gilles Remi

2016-01-01

Characterization of Mg-Si precipitates is crucial for optimizing the homogenization heat treatment of Al-Mg-Si alloys. Although sample preparation is key for high quality scanning electron microscopy imaging, most common methods lead to dealloying of Mg-Si precipitates. In this article we systematically evaluate different sample preparation methods: mechanical polishing, etching with various reagents, and electropolishing using different electrolytes. We demonstrate that the use of a nitric acid and methanol electrolyte for electropolishing a homogenized Al-Mg-Si alloy prevents the dissolution of Mg-Si precipitates, resulting in micrographs of higher quality. This preparation method is investigated in depth and the obtained scanning electron microscopy images are compared with transmission electron micrographs: the shape and size of Mg-Si precipitates appear very similar in either method. The scanning electron micrographs allow proper identification and measurement of the Mg-Si phases including needles with lengths of roughly 200 nm. These needles are β″ precipitates as confirmed by high resolution transmission electron microscopy. - Highlights: •Secondary precipitation in homogenized 6xxx Al alloys is crucial for extrudability. •Existing sample preparation methods for SEM are improvable. •Electropolishing with nitric acid/methanol yields superior quality in SEM. •The obtained micrographs are compared to TEM micrographs.

Sample preparation methods for scanning electron microscopy of homogenized Al-Mg-Si billets: A comparative study

Energy Technology Data Exchange (ETDEWEB)

Österreicher, Johannes Albert; Kumar, Manoj [LKR Light Metals Technologies Ranshofen, Austrian Institute of Technology, Postfach 26, 5282 Ranshofen (Austria); Schiffl, Andreas [Hammerer Aluminium Industries Extrusion GmbH, Lamprechtshausener Straße 69, 5282 Ranshofen (Austria); Schwarz, Sabine [University Service Centre for Transmission Electron Microscopy, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Wien (Austria); Hillebrand, Daniel [Hammerer Aluminium Industries Extrusion GmbH, Lamprechtshausener Straße 69, 5282 Ranshofen (Austria); Bourret, Gilles Remi, E-mail: gilles.bourret@sbg.ac.at [Department of Materials Science and Physics, University of Salzburg, Hellbrunner Straße 34, 5020 Salzburg (Austria)

2016-12-15

Characterization of Mg-Si precipitates is crucial for optimizing the homogenization heat treatment of Al-Mg-Si alloys. Although sample preparation is key for high quality scanning electron microscopy imaging, most common methods lead to dealloying of Mg-Si precipitates. In this article we systematically evaluate different sample preparation methods: mechanical polishing, etching with various reagents, and electropolishing using different electrolytes. We demonstrate that the use of a nitric acid and methanol electrolyte for electropolishing a homogenized Al-Mg-Si alloy prevents the dissolution of Mg-Si precipitates, resulting in micrographs of higher quality. This preparation method is investigated in depth and the obtained scanning electron microscopy images are compared with transmission electron micrographs: the shape and size of Mg-Si precipitates appear very similar in either method. The scanning electron micrographs allow proper identification and measurement of the Mg-Si phases including needles with lengths of roughly 200 nm. These needles are β″ precipitates as confirmed by high resolution transmission electron microscopy. - Highlights: •Secondary precipitation in homogenized 6xxx Al alloys is crucial for extrudability. •Existing sample preparation methods for SEM are improvable. •Electropolishing with nitric acid/methanol yields superior quality in SEM. •The obtained micrographs are compared to TEM micrographs.

The Atmospheric Scanning Electron Microscope with open sample space observes dynamic phenomena in liquid or gas.

Science.gov (United States)

Suga, Mitsuo; Nishiyama, Hidetoshi; Konyuba, Yuji; Iwamatsu, Shinnosuke; Watanabe, Yoshiyuki; Yoshiura, Chie; Ueda, Takumi; Sato, Chikara

2011-12-01

Although conventional electron microscopy (EM) requires samples to be in vacuum, most chemical and physical reactions occur in liquid or gas. The Atmospheric Scanning Electron Microscope (ASEM) can observe dynamic phenomena in liquid or gas under atmospheric pressure in real time. An electron-permeable window made of pressure-resistant 100 nm-thick silicon nitride (SiN) film, set into the bottom of the open ASEM sample dish, allows an electron beam to be projected from underneath the sample. A detector positioned below captures backscattered electrons. Using the ASEM, we observed the radiation-induced self-organization process of particles, as well as phenomena accompanying volume change, including evaporation-induced crystallization. Using the electrochemical ASEM dish, we observed tree-like electrochemical depositions on the cathode. In silver nitrate solution, we observed silver depositions near the cathode forming incidental internal voids. The heated ASEM dish allowed observation of patterns of contrast in melting and solidifying solder. Finally, to demonstrate its applicability for monitoring and control of industrial processes, silver paste and solder paste were examined at high throughput. High resolution, imaging speed, flexibility, adaptability, and ease of use facilitate the observation of previously difficult-to-image phenomena, and make the ASEM applicable to various fields. Copyright © 2011 Elsevier B.V. All rights reserved.

Power electron beam front shortening in magnetically insulated transmission line with inner coaxial dielectric insert

International Nuclear Information System (INIS)

Galstjan, E.A.; Kazanskiy, L.N.

1995-01-01

By now the technology of high-power high-current relativistic electron beams with microsecond duration has been developed. The same technology is used in high-power electric pulse generation. However at present the high-power beams of subnanosecond duration are necessary for some investigations and applications. The maximum power parameter achieved by means of the usual technology is limited by a value in the range of 100-300 MW. For this reason a search for new ways to generate high-power REB (relativistic electron beam) is a topical problem. It is obvious that this problem may be reduced to the generation of pulses with a subnanosecond front duration. There are many methods to shorten a pulse duration to its front duration for instance, by using parts of short-circuited transmission lines

Experimental Observations of In-Situ Secondary Electron Yield Reduction in the PEP-II Particle Accelerator Beam Line

International Nuclear Information System (INIS)

Pivi, Mauro

2010-01-01

Beam instability caused by the electron cloud has been observed in positron and proton storage rings and it is expected to be a limiting factor in the performance of the positron Damping Ring (DR) of future Linear Colliders (LC) such as ILC and CLIC. To test a series of promising possible electron cloud mitigation techniques as surface coatings and grooves, in the Positron Low Energy Ring (LER) of the PEP-II accelerator, we have installed several test vacuum chambers including (i) a special chamber to monitor the variation of the secondary electron yield of technical surface materials and coatings under the effect of ion, electron and photon conditioning in situ in the beam line; (ii) chambers with grooves in a straight magnetic-free section; and (iii) coated chambers in a dedicated newly installed 4-magnet chicane to study mitigations in a magnetic field region. In this paper, we describe the ongoing R and D effort to mitigate the electron cloud effect for the LC damping ring, focusing on the first experimental area and on results of the reduction of the secondary electron yield due to in situ conditioning.

Monitoring the metering performance of an electronic voltage transformer on-line based on cyber-physics correlation analysis

Science.gov (United States)

Zhang, Zhu; Li, Hongbin; Tang, Dengping; Hu, Chen; Jiao, Yang

2017-10-01

Metering performance is the key parameter of an electronic voltage transformer (EVT), and it requires high accuracy. The conventional off-line calibration method using a standard voltage transformer is not suitable for the key equipment in a smart substation, which needs on-line monitoring. In this article, we propose a method for monitoring the metering performance of an EVT on-line based on cyber-physics correlation analysis. By the electrical and physical properties of a substation running in three-phase symmetry, the principal component analysis method is used to separate the metering deviation caused by the primary fluctuation and the EVT anomaly. The characteristic statistics of the measured data during operation are extracted, and the metering performance of the EVT is evaluated by analyzing the change in statistics. The experimental results show that the method successfully monitors the metering deviation of a Class 0.2 EVT accurately. The method demonstrates the accurate evaluation of on-line monitoring of the metering performance on an EVT without a standard voltage transformer.

Monitoring the metering performance of an electronic voltage transformer on-line based on cyber-physics correlation analysis

International Nuclear Information System (INIS)

Zhang, Zhu; Li, Hongbin; Hu, Chen; Jiao, Yang; Tang, Dengping

2017-01-01

Metering performance is the key parameter of an electronic voltage transformer (EVT), and it requires high accuracy. The conventional off-line calibration method using a standard voltage transformer is not suitable for the key equipment in a smart substation, which needs on-line monitoring. In this article, we propose a method for monitoring the metering performance of an EVT on-line based on cyber-physics correlation analysis. By the electrical and physical properties of a substation running in three-phase symmetry, the principal component analysis method is used to separate the metering deviation caused by the primary fluctuation and the EVT anomaly. The characteristic statistics of the measured data during operation are extracted, and the metering performance of the EVT is evaluated by analyzing the change in statistics. The experimental results show that the method successfully monitors the metering deviation of a Class 0.2 EVT accurately. The method demonstrates the accurate evaluation of on-line monitoring of the metering performance on an EVT without a standard voltage transformer. (paper)

A four-detector spectrometer for e--γ PAC on-line with the ISOLDE-CERN isotope separator

International Nuclear Information System (INIS)

Marques, J.G.; Correia, J.G.; Melo, A.A.; Silva, M.F. da; Soares, J.C.

1995-01-01

A four-detector e - -γ spectrometer has been installed on-line with the ISOLDE isotope separator. The spectrometer consists of two magnetic lenses for detection of conversion electrons, and two BaF 2 scintillators for γ-ray detection. The spectrometer has been equipped with a 20 kV pre-acceleration system which enables detection of conversion electrons down to 2 keV. Implantation and measurement can be performed simultaneously on a large temperature range by heating or cooling the sample holder. The advantages of using the e - -γ PAC technique on-line at ISOLDE are discussed. (orig.)

Trends and perspectives of flow injection/sequential injection on-line sample-pretreatment schemes coupled to ETAAS

DEFF Research Database (Denmark)

Wang, Jianhua; Hansen, Elo Harald

2005-01-01

Flow injection (FI) analysis, the first generation of this technique, became in the 1990s supplemented by its second generation, sequential injection (SI), and most recently by the third generation (i.e.,Lab-on-Valve). The dominant role played by FI in automatic, on-line, sample pretreatments in ...

SIMS analysis using a new novel sample stage

International Nuclear Information System (INIS)

Miwa, Shiro; Nomachi, Ichiro; Kitajima, Hideo

2006-01-01

We have developed a novel sample stage for Cameca IMS-series instruments that allows us to adjust the tilt of the sample holder and to vary the height of the sample surface from outside the vacuum chamber. A third function of the stage is the capability to cool sample to -150 deg. C using liquid nitrogen. Using this stage, we can measure line profiles of 10 mm in length without any variation in the secondary ion yields. By moving the sample surface toward the input lens, the primary ion beam is well focused when the energy of the primary ions is reduced. Sample cooling is useful for samples such as organic materials that are easily damaged by primary ions or electrons

SIMS analysis using a new novel sample stage

Energy Technology Data Exchange (ETDEWEB)

Miwa, Shiro [Materials Analysis Lab., Sony Corporation, 4-16-1 Okata, Atsugi 243-0021 (Japan)]. E-mail: Shiro.Miwa@jp.sony.com; Nomachi, Ichiro [Materials Analysis Lab., Sony Corporation, 4-16-1 Okata, Atsugi 243-0021 (Japan); Kitajima, Hideo [Nanotechnos Corp., 5-4-30 Nishihashimoto, Sagamihara 229-1131 (Japan)

2006-07-30

We have developed a novel sample stage for Cameca IMS-series instruments that allows us to adjust the tilt of the sample holder and to vary the height of the sample surface from outside the vacuum chamber. A third function of the stage is the capability to cool sample to -150 deg. C using liquid nitrogen. Using this stage, we can measure line profiles of 10 mm in length without any variation in the secondary ion yields. By moving the sample surface toward the input lens, the primary ion beam is well focused when the energy of the primary ions is reduced. Sample cooling is useful for samples such as organic materials that are easily damaged by primary ions or electrons.

The Joint Structural Biology Group beam lines at the ESRF: Modern macromolecular crystallography

CERN Document Server

Mitchell, E P

2001-01-01

Macromolecular crystallography has evolved considerably over the last decade. Data sets in under an hour are now possible on high throughput beam lines leading to electron density and, possibly, initial models calculated on-site. There are five beam lines currently dedicated to macromolecular crystallography: the ID14 complex and BM-14 (soon to be superseded by ID-29). These lines handle over five hundred projects every six months and demand is increasing. Automated sample handling, alignment and data management protocols will be required to work efficiently with this demanding load. Projects developing these themes are underway within the JSBG.

On the preparation of electron sensor using LiRbSO4 samples

Science.gov (United States)

El-Muraikhi, M.; Kassem, M. E.; Gaafar, M.; Abdel Gawad, M. M. H.; Ragab, I. M.

2005-01-01

The dielectric spectroscopy of metal-metal sulfate LiRbSO4 samples are described with particular emphasis on sensor performance to be used in the field of radiation. The obtained results as the effect of different electron energy beams at fixed dose, 0.5 Gy, showed abrupt change of the electrical properties (electrical conductivity, capacitance, and loss tangent). The results can be explained on the basis of radiation-induced defects followed by radiation quenching. The prepared samples can be used in the field of radiation dosimeter.

A new Langmuir probe concept for rapid sampling of space plasma electron density

International Nuclear Information System (INIS)

Jacobsen, K S; Pedersen, A; Moen, J I; Bekkeng, T A

2010-01-01

In this paper we describe a new Langmuir probe concept that was invented for the in situ investigation of HF radar backscatter irregularities, with the capability to measure absolute electron density at a resolution sufficient to resolve the finest conceivable structure in an ionospheric plasma. The instrument consists of two or more fixed-bias cylindrical Langmuir probes whose radius is small compared to the Debye length. With this configuration, it is possible to acquire absolute electron density measurements independent of electron temperature and rocket/satellite potential. The system was flown on the ICI-2 sounding rocket to investigate the plasma irregularities which cause HF backscatter. It had a sampling rate of more than 5 kHz and successfully measured structures down to the scale of one electron gyro radius. The system can easily be adapted for any ionospheric rocket or satellite, and provides high-quality measurements of electron density at any desired resolution

Use of an Electronic Tongue System and Fuzzy Logic to Analyze Water Samples

Science.gov (United States)

Braga, Guilherme S.; Paterno, Leonardo G.; Fonseca, Fernando J.

2009-05-01

An electronic tongue (ET) system incorporating 8 chemical sensors was used in combination with two pattern recognition tools, namely principal component analysis (PCA) and Fuzzy logic for discriminating/classification of water samples from different sources (tap, distilled and three brands of mineral water). The Fuzzy program exhibited a higher accuracy than the PCA and allowed the ET to classify correctly 4 in 5 types of water. Exception was made for one brand of mineral water which was sometimes misclassified as tap water. On the other hand, the PCA grouped water samples in three clusters, one with the distilled water; a second with tap water and one brand of mineral water, and the third with the other two other brands of mineral water. Samples in the second and third clusters could not be distinguished. Nevertheless, close grouping between repeated tests indicated that the ET system response is reproducible. The potential use of the Fuzzy logic as the data processing tool in combination with an electronic tongue system is discussed.

[Occupational stress in assembly line workers in electronics manufacturing service and related influencing factors].

Science.gov (United States)

Ji, Y Q; Li, S; Wang, C; Wang, J; Liu, X M

2016-10-20

Objective: To investigate occupational stress in assembly line workers in electronics manu-facturing service (EMS) and related influencing factors. Methods: From June to October, 2015, a cross-sectional survey was performed for 5 944 assembly line workers in EMS (observation group) and 6 270 workers from other posts (non-assembly line workers and management personnel; control group) using the self-made questionnaire for basic information, job demand-control (JDC) model questionnaire, and effort-reward imbalance (ERI) model questionnaire to collect respondents' basic information and occupational stress. Results: The observation group had significantly lower work autonomy, social support, and work reward scores than the control group (2.72 ± 0.63/3.64 ± 0.68/4.06 ± 0.80 vs 3.00 ± 0.67/3.83 ± 0.68/4.24 ± 0.75, t =23.53, 15.41, and 12.70, all P occupational stress determined by JDC and ERI models than the control group (64.5%/12.7% vs 52.6%/9.9%, χ 2 =182.26 and 23.41, both P 60 hours/week, and sleeping time occupational stress in JDC model; education background of Bachelor's degree or above, working time >60 hours/week, and sleeping timeoccupational stress in ERI model, while female sex and a high monthly income reduced the risk of occupational stress in ERI model. Conclusion: Assembly line workers in EMS are a relatively vulnerable group and have a high degree of occupational stress. Working time >60 hours/week and sleeping time occupational stress.

Relativistic electron influence on sanitary-model microorganisms and antibiotics in model samples

International Nuclear Information System (INIS)

Antipov, V.S.; Berezhna, I.V.; Kovpik, O.F.; Babych, E.M.; Voliansky, Yu.L.; Sklar, N.I.

2004-01-01

A series of the investigations of the electron beam influence on sanitary-model test cultures and antibiotics in model solutions has been carried out. For each of the test objects, the authors have found the boundary doses of the absorbed radiation. The higher doses cause the sharp increase in the bactericidal influence, which becomes complete. The sanitary-bactericidal indices of the water samples remain sable during 6 days. The samples of antibiotics in various concentrations (from 100 UA) have been irradiated. It is proved that the substratum processing by the beam (in the regimes 30 kGy) causes diminution and complete neutralization of the antibacterial activity in all probes of the samples

Determination of cobalt in biological samples by line-source and high-resolution continuum source graphite furnace atomic absorption spectrometry using solid sampling or alkaline treatment

International Nuclear Information System (INIS)

Ribeiro, Anderson Schwingel; Vieira, Mariana Antunes; Furtado da Silva, Alessandra; Borges, Daniel L. Gallindo; Welz, Bernhard; Heitmann, Uwe; Curtius, Adilson Jose

2005-01-01

Two procedures for the determination of Co in biological samples by graphite furnace atomic absorption spectrometry (GF AAS) were compared: solid sampling (SS) and alkaline treatment with tetramethylammonium hydroxide (TMAH) using two different instruments for the investigation: a conventional line-source (LS) atomic absorption spectrometer and a prototype high-resolution continuum source atomic absorption spectrometer. For the direct introduction of the solid samples, certified reference materials (CRM) were ground to a particle size ≤50 μm. Alkaline treatment was carried out by placing about 250 mg of the sample in polypropylene flasks, adding 2 mL of 25% m/v tetramethylammonium hydroxide and de-ionized water. Due to its unique capacity of providing a 3-D spectral plot, a high-resolution continuum source (HR-CS) graphite furnace atomic absorption spectrometry was used as a tool to evaluate potential spectral interferences, including background absorption for both sample introduction procedures, revealing that a continuous background preceded the atomic signal for pyrolysis temperatures lower than 700 deg. C. Molecular absorption bands with pronounced rotational fine structure appeared for atomization temperatures >1800 deg. C probably as a consequence of the formation of PO. After optimization had been carried out using high resolution continuum source atomic absorption spectrometry, the optimized conditions were adopted also for line-source atomic absorption spectrometry. Six biological certified reference materials were analyzed, with calibration against aqueous standards, resulting in agreement with the certified values (according to the t-test for a 95% confidence level) and in detection limits as low as 5 ng g -1

Simultaneous determination of sample thickness, tilt, and electron mean free path using tomographic tilt images based on Beer-Lambert law.

Science.gov (United States)

Yan, Rui; Edwards, Thomas J; Pankratz, Logan M; Kuhn, Richard J; Lanman, Jason K; Liu, Jun; Jiang, Wen

2015-11-01

Cryo-electron tomography (cryo-ET) is an emerging technique that can elucidate the architecture of macromolecular complexes and cellular ultrastructure in a near-native state. Some important sample parameters, such as thickness and tilt, are needed for 3-D reconstruction. However, these parameters can currently only be determined using trial 3-D reconstructions. Accurate electron mean free path plays a significant role in modeling image formation process essential for simulation of electron microscopy images and model-based iterative 3-D reconstruction methods; however, their values are voltage and sample dependent and have only been experimentally measured for a limited number of sample conditions. Here, we report a computational method, tomoThickness, based on the Beer-Lambert law, to simultaneously determine the sample thickness, tilt and electron inelastic mean free path by solving an overdetermined nonlinear least square optimization problem utilizing the strong constraints of tilt relationships. The method has been extensively tested with both stained and cryo datasets. The fitted electron mean free paths are consistent with reported experimental measurements. The accurate thickness estimation eliminates the need for a generous assignment of Z-dimension size of the tomogram. Interestingly, we have also found that nearly all samples are a few degrees tilted relative to the electron beam. Compensation of the intrinsic sample tilt can result in horizontal structure and reduced Z-dimension of tomograms. Our fast, pre-reconstruction method can thus provide important sample parameters that can help improve performance of tomographic reconstruction of a wide range of samples. Copyright © 2015 Elsevier Inc. All rights reserved.

Density-dependent lines of one- and two-electron ions in diagnostics of laboratory plasma. I. The rates of collision relaxation of excited levels

Energy Technology Data Exchange (ETDEWEB)

Shevelko, V P; Skobelev, I Yu; Vinogradov, A V [Lebedev Physical Institute, Academy of Sciences of the USSR, Moscow, USSR

1977-01-01

Plasma devices with inertial plasma confinement such as laser produced plasmas, exploding wires, plasma focus, etc., which have been rapidly developed during recent years., appear to be very intensive sources of spectral line radiation in far UV and X-ray regions. Analysis of this radiation provides a good tool for plasma diagnostics with very high electron densities up to 10/sup 22/cm/sup -3/. In this work, consisting of two parts, the authors consider the mechanism of the formation of spectral lines in hot and dense plasma. The key point for density diagnostics is the fact that for some ion levels the rate of collisional relaxation has the same order of magnitude as the radiative decay. Thus the intensities of spectral lines arising from these levels show a strong dependence on electron density which makes diagnostics possible. In this paper, emphasis is laid on the calculation of rates of transition between close ion levels induced by electron or ion impact, which usually gives the main contribution to the collisional relaxation constants. The influence of plasma polarization effects on the collision frequency in a dense plasma is also considered.

Electronic transport of bilayer graphene with asymmetry line defects

Science.gov (United States)

Zhao, Xiao-Ming; Wu, Ya-Jie; Chen, Chan; Liang, Ying; Kou, Su-Peng

2016-11-01

In this paper, we study the quantum properties of a bilayer graphene with (asymmetry) line defects. The localized states are found around the line defects. Thus, the line defects on one certain layer of the bilayer graphene can lead to an electric transport channel. By adding a bias potential along the direction of the line defects, we calculate the electric conductivity of bilayer graphene with line defects using the Landauer-Büttiker theory, and show that the channel affects the electric conductivity remarkably by comparing the results with those in a perfect bilayer graphene. This one-dimensional line electric channel has the potential to be applied in nanotechnology engineering. Project supported by the National Basic Research Program of China (Grant Nos. 2011CB921803 and 2012CB921704), the National Natural Science Foundation of China (Grant Nos. 11174035, 11474025, 11504285, and 11404090), the Specialized Research Fund for the Doctoral Program of Higher Education, China, the Fundamental Research Funds for the Central Universities, China, the Scientific Research Program Fund of the Shaanxi Provincial Education Department, China (Grant No. 15JK1363), and the Young Talent Fund of University Association for Science and Technology in Shaanxi Province, China.

Experimental transition probabilities for several spectral lines arising from the 5d10 6s{8s, 7p, 5f, 5g} electronic configurations of Pb III

International Nuclear Information System (INIS)

Alonso-Medina, A.

2010-01-01

Transition probabilities for 30 spectral lines, arising from the 5d 10 6s{8s, 7p, 5f, 5g} electronic configurations of Pb III (20 measured for the first time), have been experimentally determined from measurements of emission line intensities in a plasma lead induced by ablation with a Nd:YAG laser. The line intensities were obtained with the target placed in molecular argon at 6 Torr, recorded at a 400 ns delay from the laser pulse, which provides appropriate measurement conditions, and analysed between 200 and 700 nm. They are measured when the plasma reaches local thermodynamic equilibrium (LTE). The plasma under study had an electron temperature (T) of 21,400 K and an electron number density (N e ) of 7x10 16 cm -3 . The influence of self-absorption has been estimated for every line, and plasma homogeneity has been checked. The values obtained were compared with previous experimental values and theoretical estimates where possible.

Power flow studies of magnetically insulated lines

International Nuclear Information System (INIS)

McDaniel, D.H.; Poukey, J.W.; Bergeron, K.D.; VanDevender, J.P.; Johnson, D.L.

1977-01-01

The designs for relativistic electron beam accelerators with power levels of 20 to 100 TW are greatly restricted by the inductance of a single diode of reasonable size. This fact leads to modular designs of very large accelerators. One concept uses several small insulators at a large radius arranged around the accelerator center. The total effective inductance is then low, but the energy must then be transported by self-magnetic insulated vacuum lines to the target volume. A triplate vacuum line configuration eases many mechanical support problems and allows more A-K gaps or feeds to be packaged around a given radius. This type of vacuum transmission line was chosen for initial experiments at Sandia. The experiments were conducted on the MITE (Magnetically Insulated Transmission Experiment) accelerator. The water pulse forming lines are connected to a vacuum triplate line through a conventional stacked insulator. Diagnostics on the experiment consisted of: (1) input V; (2) input I; (3) I monitors at the input, middle, and output of both the center conductor and ground plane of the transmission line; (4) magnetic energy analyzer to view peak electron energy in the A-K gap; (5) calorimetry; and (6) Faraday cups to look at electron current flowing across the transmission line. The main goal of the experiment is to obtain input impedance of the transmission line as a function of voltage and to measure electron loss currents. These measurements are compared to theoretical models for the input impedance and energy losses

Size characterization of airborne SiO{sub 2} nanoparticles with on-line and off-line measurement techniques: an interlaboratory comparison study

Energy Technology Data Exchange (ETDEWEB)

Motzkus, C., E-mail: charles.motzkus@lne.fr; Mace, T.; Gaie-Levrel, F.; Ducourtieux, S.; Delvallee, A. [Laboratoire National de Metrologie et d' Essais (LNE) (France); Dirscherl, K. [Danish Fundamental Metrology (DFM) (Denmark); Hodoroaba, V.-D. [BAM Federal Institute for Materials Research and Testing (Germany); Popov, I. [The Hebrew University of Jerusalem, Unit for Nanocharacterization (Israel); Popov, O.; Kuselman, I. [National Physical Laboratory of Israel (INPL) (Israel); Takahata, K.; Ehara, K. [National Institute of Advanced Industrial Science and Technology (AIST), National Metrology Institute of Japan (NMIJ) (Japan); Ausset, P.; Maille, M. [Universite Paris-Est Creteil et Universite Paris-Diderot, Laboratoire Interuniversitaire des Systemes Atmospheriques (LISA), UMR CNRS 7583 (France); Michielsen, N.; Bondiguel, S.; Gensdarmes, F. [Institut de Radioprotection et de Surete Nucleaire (IRSN), PSN-RES, SCA, LPMA (France); Morawska, L.; Johnson, G. R.; Faghihi, E. M. [Queensland University of Technology (QUT), International Laboratory for Air Quality and Health (ILAQH) (Australia); and others

2013-10-15

Results of an interlaboratory comparison on size characterization of SiO{sub 2} airborne nanoparticles using on-line and off-line measurement techniques are discussed. This study was performed in the framework of Technical Working Area (TWA) 34-'Properties of Nanoparticle Populations' of the Versailles Project on Advanced Materials and Standards (VAMAS) in the project no. 3 'Techniques for characterizing size distribution of airborne nanoparticles'. Two types of nano-aerosols, consisting of (1) one population of nanoparticles with a mean diameter between 30.3 and 39.0 nm and (2) two populations of non-agglomerated nanoparticles with mean diameters between, respectively, 36.2-46.6 nm and 80.2-89.8 nm, were generated for characterization measurements. Scanning mobility particle size spectrometers (SMPS) were used for on-line measurements of size distributions of the produced nano-aerosols. Transmission electron microscopy, scanning electron microscopy, and atomic force microscopy were used as off-line measurement techniques for nanoparticles characterization. Samples were deposited on appropriate supports such as grids, filters, and mica plates by electrostatic precipitation and a filtration technique using SMPS controlled generation upstream. The results of the main size distribution parameters (mean and mode diameters), obtained from several laboratories, were compared based on metrological approaches including metrological traceability, calibration, and evaluation of the measurement uncertainty. Internationally harmonized measurement procedures for airborne SiO{sub 2} nanoparticles characterization are proposed.

Paleoclassical electron heat transport

International Nuclear Information System (INIS)

Callen, J.D.

2005-01-01

Radial electron heat transport in low collisionality, magnetically-confined toroidal plasmas is shown to result from paleoclassical Coulomb collision processes (parallel electron heat conduction and magnetic field diffusion). In such plasmas the electron temperature equilibrates along magnetic field lines a long length L, which is the minimum of the electron collision length and a maximum effective half length of helical field lines. Thus, the diffusing field lines induce a radial electron heat diffusivity M ≅ L/(πR 0q ) ∼ 10 >> 1 times the magnetic field diffusivity η/μ 0 ≅ ν e (c/ω p ) 2 . The paleoclassical electron heat flux model provides interpretations for many features of 'anomalous' electron heat transport: magnitude and radial profile of electron heat diffusivity (in tokamaks, STs, and RFPs), Alcator scaling in high density plasmas, transport barriers around low order rational surfaces and near a separatrix, and a natural heat pinch (or minimum temperature gradient) heat flux form. (author)

Evaluating the accuracy of sampling to estimate central line-days: simplification of the National Healthcare Safety Network surveillance methods.

Science.gov (United States)

Thompson, Nicola D; Edwards, Jonathan R; Bamberg, Wendy; Beldavs, Zintars G; Dumyati, Ghinwa; Godine, Deborah; Maloney, Meghan; Kainer, Marion; Ray, Susan; Thompson, Deborah; Wilson, Lucy; Magill, Shelley S

2013-03-01

To evaluate the accuracy of weekly sampling of central line-associated bloodstream infection (CLABSI) denominator data to estimate central line-days (CLDs). Obtained CLABSI denominator logs showing daily counts of patient-days and CLD for 6-12 consecutive months from participants and CLABSI numerators and facility and location characteristics from the National Healthcare Safety Network (NHSN). Convenience sample of 119 inpatient locations in 63 acute care facilities within 9 states participating in the Emerging Infections Program. Actual CLD and estimated CLD obtained from sampling denominator data on all single-day and 2-day (day-pair) samples were compared by assessing the distributions of the CLD percentage error. Facility and location characteristics associated with increased precision of estimated CLD were assessed. The impact of using estimated CLD to calculate CLABSI rates was evaluated by measuring the change in CLABSI decile ranking. The distribution of CLD percentage error varied by the day and number of days sampled. On average, day-pair samples provided more accurate estimates than did single-day samples. For several day-pair samples, approximately 90% of locations had CLD percentage error of less than or equal to ±5%. A lower number of CLD per month was most significantly associated with poor precision in estimated CLD. Most locations experienced no change in CLABSI decile ranking, and no location's CLABSI ranking changed by more than 2 deciles. Sampling to obtain estimated CLD is a valid alternative to daily data collection for a large proportion of locations. Development of a sampling guideline for NHSN users is underway.

Lifetime measurements using the Jefferson Lad Load-Lock Electron Gun

International Nuclear Information System (INIS)

J. Grames; P. Adderley; M. Baylac; J. Brittian; D. Charles; J. Clark; J. Hansknecht; M. Poelker; M. Stutzman; K. Surles-Law

2000-01-01

Lifetime measurements of bulk GaAs using a 100 kV load-lock electron gun and beam line were made. Initial tests used anodized samples to study lifetime under various conditions (gun vacuum, laser spot location, activated area). Subsequent tests used a mechanical mask to limit the active area and included improved monitoring of the gun chamber and beam line vacuum pressure. Results of these measurements support claims made at past workshops, namely photocathode lifetime improves when gun vacuum is enhanced and when electron emission from the edge of the photocathode is eliminated. The dependence upon laser spot location is less certain. Tests studying lifetime at higher beam intensity (I ∼ 8 mA) have begun

Noninvasive Sampling of Mucosal Lining Fluid for the Quantification of In Vivo Upper Airway Immune-mediator Levels

DEFF Research Database (Denmark)

Wolsk, Helene Mygind; Chawes, Bo L.; Thorsen, Jonathan

2017-01-01

(often used by other techniques). The mucosal lining fluid is sampled on a strip of filter paper placed at the anterior part of the inferior turbinate and left for 2 min of absorption. Analytes are eluted from the filter papers, and the extracted protein-based eluates are analyzed...

Liquid sampling-atmospheric pressure glow discharge as a secondary excitation source: Assessment of plasma characteristics

International Nuclear Information System (INIS)

Manard, Benjamin T.; Gonzalez, Jhanis J.; Sarkar, Arnab; Dong, Meirong; Chirinos, Jose; Mao, Xianglei; Russo, Richard E.; Marcus, R. Kenneth

2014-01-01

The liquid sampling-atmospheric pressure glow discharge (LS-APGD) has been assessed as a secondary excitation source with a parametric evaluation regarding carrier gas flow rate, applied current, and electrode distance. With this parametric evaluation, plasma optical emission was monitored in order to obtain a fundamental understanding with regards to rotational temperature (T rot ), excitation temperature (T exc ), electron number density (n e ), and plasma robustness. Incentive for these studies is not only for a greater overall fundamental knowledge of the APGD, but also in instrumenting a secondary excitation/ionization source following laser ablation (LA). Rotational temperatures were determined through experimentally fitting of the N 2 and OH molecular emission bands while atomic excitation temperatures were calculated using a Boltzmann distribution of He and Mg atomic lines. The rotational and excitation temperatures were determined to be ∼ 1000 K and ∼ 2700 K respectively. Electron number density was calculated to be on the order of ∼ 3 × 10 15 cm −3 utilizing Stark broadening effects of the Hα line of the Balmer series and a He I transition. In addition, those diagnostics were performed introducing magnesium (by solution feed and laser ablation) into the plasma in order to determine any perturbation under heavy matrix sampling. The so-called plasma robustness factor, derived by monitoring Mg II/Mg I emission ratios, is also employed as a reflection of potential perturbations in microplasma energetics across the various operation conditions and sample loadings. While truly a miniaturized source ( 3 volume), the LS-APGD is shown to be quite robust with plasma characteristics and temperatures being unaffected upon introduction of metal species, whether by liquid or laser ablation sample introduction. - Highlights: • Liquid sampling-atmospheric pressure glow discharge (LS-APGD) • LS-APGD as a secondary excitation source for laser-ablated (LA

An extreme Fe II emitter the narrow line quasar PHL 1092

CERN Document Server

Bergeron, J

1980-01-01

A search for Fe II emission in a sample of radio-quiet quasars has revealed the outstanding properties of PHL 1092. Intense Fe II lines dominate the entire spectrum, and the Fe II UV multiplets are nearly as strong as the optical ones. In contrast the extreme weakness of the Balmer and Mg II lines is striking. For the first time, Fe I lines are identified in an extra-galactic object. The lines are narrow, with a FWHM of 1300 km s/sup -1/. The presence of Fe II UV lines and Fe I lines from the ground state requires moderate column densities. However Fe/sup 0/ can exist only in a region completely shielded from the UV continuum. The weakness of Mg II and H beta relative to Fe II lines is best explained by their thermalization. The emitting region is of high electron density n/sub e/ approximately=10/sup 12/ cm/sup -3/, low temperature T approximately=10000K, and has an optical depth in the Fe II UV lines tau /sub UV/ approximately=10/sup 3/-10/sup 4/. It is speculated that for higher densities all the lines wou...

Analysis of plant hormones by microemulsion electrokinetic capillary chromatography coupled with on-line large volume sample stacking.

Science.gov (United States)

Chen, Zongbao; Lin, Zian; Zhang, Lin; Cai, Yan; Zhang, Lan

2012-04-07

A novel method of microemulsion electrokinetic capillary chromatography (MEEKC) coupled with on-line large volume sample stacking was developed for the analysis of six plant hormones including indole-3-acetic acid, indole-3-butyric acid, indole-3-propionic acid, 1-naphthaleneacetic acid, abscisic acid and salicylic acid. Baseline separation of six plant hormones was achieved within 10 min by using the microemulsion background electrolyte containing a 97.2% (w/w) 10 mM borate buffer at pH 9.2, 1.0% (w/w) ethyl acetate as oil droplets, 0.6% (w/w) sodium dodecyl sulphate as surfactant and 1.2% (w/w) 1-butanol as cosurfactant. In addition, an on-line concentration method based on a large volume sample stacking technique and multiple wavelength detection was adopted for improving the detection sensitivity in order to determine trace level hormones in a real sample. The optimal method provided about 50-100 fold increase in detection sensitivity compared with a single MEEKC method, and the detection limits (S/N = 3) were between 0.005 and 0.02 μg mL(-1). The proposed method was simple, rapid and sensitive and could be applied to the determination of six plant hormones in spiked water samples, tobacco leaves and 1-naphthylacetic acid in leaf fertilizer. The recoveries ranged from 76.0% to 119.1%, and good reproducibilities were obtained with relative standard deviations (RSDs) less than 6.6%.

High-power, high-brightness pseudospark-produced electron beam driven by improved pulse line accelerator

International Nuclear Information System (INIS)

Junbino Zhu; Mingchang Wang; Zhijiang Wang

1995-01-01

A high power (200KV), intense current density, low emittance (71mmmrad), high brightness (8x10 10 A/m rad) electron beam was generated in the 10cm long, high-voltage-resistive multi-gap hollow cathode pseudospark chamber filled with 15pa nitrogen and driven by an improved pulse line accelerator. The beam was ejected with the 1mm diameter, the 2.2KA beam current, and the 400ns pulse length, and could propagated 20cm in the drift tube. At a distance of 5cm from the anode it penetrated consecutively an acid-sensitive discoloring film and a 0.05mm-thick copper foil both stuck closely, left 0.6mm and 0.3mm holes on them, respectively. That 10 shots on an acid-sensitive film produced a hole of 1.6mm at 7cm downstream of anode showed its good repeatability. After 60 shots the pseudospark discharge chamber was disassembled and observed that almost no destructive damage traces left on the surfaces of its various electrodes and insulators. But on almost all the surfaces of changeable central hole parts installed on intermediate electrodes there are traces of electron emission from the sides facing the anode and of bombardment on the sides facing the cathode, in contrast with which on the front- and back-surfaces of hollow cathode no visible traces of electron emission from then was observed. In addition, there were different tints, strip-like regions on the side of anode facing the cathode. Another interesting phenomenon was that there were a set of concentric circular or elliptical ring pattern on the acid-sensitive discoloring film got at 5cm from the anode and observed tinder a metallograph. It seems that the pseudospark electron beam is Laminar beam i.e, being possessed of a multi-layer structure, at least in the case of multi-gap pseudospark discharge chamber. It was found experimentally that the quality of pseudospark electron beam is much better than that of the cold-cathode electron beam

A Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for In-Situ Mars Surface Sample Analysis

Science.gov (United States)

Edmunson, J.; Gaskin, J. A.; Jerman, G. A.; Harvey, R. P.; Doloboff, I. J.; Neidholdt, E. L.

2016-01-01

The Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) project, funded by the NASA Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) Research Opportunities in Space and Earth Sciences (ROSES), will build upon previous miniaturized SEM designs and recent advancements in variable pressure SEM's to design and build a SEM to complete analyses of samples on the surface of Mars using the atmosphere as an imaging medium. This project is a collaboration between NASA Marshall Space Flight Center (MSFC), the Jet Propulsion Laboratory (JPL), electron gun and optics manufacturer Applied Physics Technologies, and small vacuum system manufacturer Creare. Dr. Ralph Harvery and environmental SEM (ESEM) inventor Dr. Gerry Danilatos serve as advisors to the team. Variable pressure SEMs allow for fine (nm-scale) resolution imaging and micron-scale chemical study of materials without sample preparation (e.g., carbon or gold coating). Charging of a sample is reduced or eliminated by the gas surrounding the sample. It is this property of ESEMs that make them ideal for locations where sample preparation is not yet feasible, such as the surface of Mars. In addition, the lack of sample preparation needed here will simplify the sample acquisition process and allow caching of the samples for future complementary payload use.

Metal-poor dwarf galaxies in the SIGRID galaxy sample. I. H II region observations and chemical abundances

International Nuclear Information System (INIS)

Nicholls, David C.; Dopita, Michael A.; Sutherland, Ralph S.; Jerjen, Helmut; Kewley, Lisa J.; Basurah, Hassan

2014-01-01

In this paper we present the results of observations of 17 H II regions in thirteen galaxies from the SIGRID sample of isolated gas-rich irregular dwarf galaxies. The spectra of all but one of the galaxies exhibit the auroral [O III] 4363 Å line, from which we calculate the electron temperature, T e , and gas-phase oxygen abundance. Five of the objects are blue compact dwarf galaxies, of which four have not previously been analyzed spectroscopically. We include one unusual galaxy which exhibits no evidence of the [N II] λλ 6548,6584 Å lines, suggesting a particularly low metallicity (< Z ☉ /30). We compare the electron temperature based abundances with those derived using eight of the new strong-line diagnostics presented by Dopita et al. Using a method derived from first principles for calculating total oxygen abundance, we show that the discrepancy between the T e -based and strong-line gas-phase abundances have now been reduced to within ∼0.07 dex. The chemical abundances are consistent with what is expected from the luminosity-metallicity relation. We derive estimates of the electron densities and find them to be between ∼5 and ∼100 cm –3 . We find no evidence for a nitrogen plateau for objects in this sample with metallicities 0.5 > Z ☉ > 0.15.

Metal-poor dwarf galaxies in the SIGRID galaxy sample. I. H II region observations and chemical abundances

Energy Technology Data Exchange (ETDEWEB)

Nicholls, David C.; Dopita, Michael A.; Sutherland, Ralph S.; Jerjen, Helmut; Kewley, Lisa J. [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston ACT 2611 (Australia); Basurah, Hassan, E-mail: David.Nicholls@anu.edu.au [Astronomy Department, King Abdulaziz University, P.O. Box 80203 Jeddah (Saudi Arabia)

2014-05-10

In this paper we present the results of observations of 17 H II regions in thirteen galaxies from the SIGRID sample of isolated gas-rich irregular dwarf galaxies. The spectra of all but one of the galaxies exhibit the auroral [O III] 4363 Å line, from which we calculate the electron temperature, T{sub e} , and gas-phase oxygen abundance. Five of the objects are blue compact dwarf galaxies, of which four have not previously been analyzed spectroscopically. We include one unusual galaxy which exhibits no evidence of the [N II] λλ 6548,6584 Å lines, suggesting a particularly low metallicity (< Z {sub ☉}/30). We compare the electron temperature based abundances with those derived using eight of the new strong-line diagnostics presented by Dopita et al. Using a method derived from first principles for calculating total oxygen abundance, we show that the discrepancy between the T{sub e} -based and strong-line gas-phase abundances have now been reduced to within ∼0.07 dex. The chemical abundances are consistent with what is expected from the luminosity-metallicity relation. We derive estimates of the electron densities and find them to be between ∼5 and ∼100 cm{sup –3}. We find no evidence for a nitrogen plateau for objects in this sample with metallicities 0.5 > Z {sub ☉} > 0.15.

Real-time control of tearing modes using a line-of-sight electron cyclotron emission diagnostic

International Nuclear Information System (INIS)

Hennen, B A; Westerhof, E; De Baar, M R; Bongers, W A; Thoen, D J; Nuij, P W J M; Steinbuch, M; Oosterbeek, J W; Buerger, A

2010-01-01

The stability and performance of tokamak plasmas are limited by instabilities such as neoclassical tearing modes. This paper reports on an experimental proof of principle of a feedback control approach for real-time, autonomous suppression and stabilization of tearing modes in a tokamak. The system combines an electron cyclotron emission diagnostic for sensing of the tearing modes in the same sight line with a steerable electron cyclotron resonance heating and current drive (ECRH/ECCD) antenna. A methodology for fast detection of q = m/n = 2/1 tearing modes and retrieval of their location, rotation frequency and phase is presented. Set-points to establish alignment of the ECRH/ECCD deposition location with the centre of the tearing mode are generated in real time and forwarded in closed loop to the steerable launcher and as a modulation pulse train to the gyrotron. Experimental results demonstrate the capability of the control system to track externally perturbed tearing modes in real time.

Metal-organic framework MIL-101 as sorbent based on double-pumps controlled on-line solid-phase extraction coupled with high-performance liquid chromatography for the determination of flavonoids in environmental water samples.

Science.gov (United States)

Liu, Yue; Hu, Jia; Li, Yan; Li, Xiao-Shuang; Wang, Zhong-Liang

2016-10-01

A novel method with high sensitivity for the rapid determination of chrysin, apigenin and luteolin in environment water samples was developed by double-pumps controlled on-line solid-phase extraction (SPE) coupled with high-performance liquid chromatography (HPLC). In the developed technique, metal organic framework MIL-101 was synthesized and applied as a sorbent for SPE. The as-synthesized MIL-101 was characterized by scanning electron microscope, X-ray diffraction spectrometry, thermal gravimetric analysis and micropore physisorption analysis. The MIL-101 behaved as a fast kinetics in the adsorption of chrysin, apigenin and luteolin. On-line SPE of chrysin, apigenin and luteolin was processed by loading a sample solution at a flow rate of 1.0 mL/min for 10 min. The extracted analytes were subsequently eluted into a ZORBAX Bonus-RP analytical column (25 cm long × 4.6 mm i.d.) for HPLC separation under isocratic condition with a mobile phase (MeOH: ACN: 0.02 M H 3 PO 4 = 35:35:30) at a flow rate of 1.0 mL/min. Experimental conditions, including ionic strength, sample pH, sample loading rates, sample loading time and desorption analytes time, were further optimized to obtain efficient preconcentration and high-precision determination of the analytes mentioned above. The method achieved the merits of simplicity, rapidity, sensitivity, wide linear range and high sample throughput. The possible mechanism for the adsorption of flavonoids on MIL-101 was proposed. The developed method has been applied to determine trace chrysin, apigenin and luteolin in a variety of environmental water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Argon line broadening by neutral atoms and application to the measurement of oscillator strengths of AI resonance lines

International Nuclear Information System (INIS)

Vallee, O.; Ranson, P.; Chapelle, J.

1977-01-01

AI line broadening was studied from collisions between neutral argon atoms (3p 5 4p-3p 5 4s transitions) in a weakly ionised plasma jet (neutral atoms temperature T 0 approximately 4000K, electrons temperature Tsub(e) approximately 6000K, electronic density Nsub(e) 15 cm -3 , ionisation rate α -4 , and pressure range from 1 to 3 kg/cm 2 ). A satisfactory description of Van der Waals broadened lines is obtained by means of a Lennard-Jones potential. Measurement of line widths whose corresponding transitions occur on resonant levels, gives with relatively good accuracy the oscillator strength of the argon resonance lines [fr

The effect of electron thermal conduction on plasma pressure gradient during reconnection of magnetic field lines

International Nuclear Information System (INIS)

Chu, T.K.

1987-12-01

The interplay of electron cross-field thermal conduction and the reconnection of magnetic field lines around an m = 1 magnetic island prior to a sawtooth crash can generate a large pressure gradient in a boundary layer adjacent to the reconnecting surface, leading to an enhanced gradient of poloidal beta to satisfy the threshold condition for ideal MHD modes. This narrow boundary layer and the short onset time of a sawtooth crash can be supported by fine-grained turbulent processes in a tokamak plasma. 11 refs

Assessment of printability for printed electronics patterns by measuring geometric dimensions and defining assessment parameters

Energy Technology Data Exchange (ETDEWEB)

Jeon, Sung Woong [Dept. of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu (Korea, Republic of); Kim, Cheol; Kim, Chung Hwan [Chungnam National University, Daejeon (Korea, Republic of)

2016-12-15

The printability of patterns for printed electronic devices determines the performance, yield rate, and reliability of the devices; therefore, it should be assessed quantitatively. In this paper, parameters for printability assessment of printed patterns for width, pinholes, and edge waviness are suggested. For quantitative printability assessment, printability grades for each parameter are proposed according to the parameter values. As examples of printability assessment, printed line patterns and mesh patterns obtained using roll-to-roll gravure printing are used. Both single-line patterns and mesh patterns show different levels of printability, even in samples obtained using the same printing equipment and conditions. Therefore, for reliable assessment, it is necessary to assess the printability of the patterns by enlarging the sampling area and increasing the number of samples. We can predict the performance of printed electronic devices by assessing the printability of the patterns that constitute them.

Assessment of printability for printed electronics patterns by measuring geometric dimensions and defining assessment parameters

International Nuclear Information System (INIS)

Jeon, Sung Woong; Kim, Cheol; Kim, Chung Hwan

2016-01-01

The printability of patterns for printed electronic devices determines the performance, yield rate, and reliability of the devices; therefore, it should be assessed quantitatively. In this paper, parameters for printability assessment of printed patterns for width, pinholes, and edge waviness are suggested. For quantitative printability assessment, printability grades for each parameter are proposed according to the parameter values. As examples of printability assessment, printed line patterns and mesh patterns obtained using roll-to-roll gravure printing are used. Both single-line patterns and mesh patterns show different levels of printability, even in samples obtained using the same printing equipment and conditions. Therefore, for reliable assessment, it is necessary to assess the printability of the patterns by enlarging the sampling area and increasing the number of samples. We can predict the performance of printed electronic devices by assessing the printability of the patterns that constitute them

Multiple Lines of Evidence

Energy Technology Data Exchange (ETDEWEB)

Amidan, Brett G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Venzin, Alexander M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Bramer, Lisa M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2015-06-03

This paper discusses the process of identifying factors that influence the contamination level of a given decision area and then determining the likelihood that the area remains unacceptable. This process is referred to as lines of evidence. These lines of evidence then serve as inputs for the stratified compliance sampling (SCS) method, which requires a decision area to be divided into strata based upon contamination expectations. This is done in order to focus sampling efforts more within stratum where contamination is more likely and to use the domain knowledge about these likelihoods of the stratum remaining unacceptable to buy down the number of samples necessary, if possible. Two different building scenarios were considered as an example (see Table 3.1). SME expertise was elicited concerning four lines of evidence factors (see Table 3.2): 1) amount of contamination that was seen before decontamination, 2) post-decontamination air sampling information, 3) the applied decontaminant information, and 4) the surface material. Statistical experimental design and logistic regression modelling were used to help determine the likelihood that example stratum remained unacceptable for a given example scenario. The number of samples necessary for clearance was calculated by applying the SCS method to the example scenario, using the estimated likelihood of each stratum remaining unacceptable as was determined using the lines of evidence approach. The commonly used simple random sampling (SRS) method was also used to calculate the number of samples necessary for clearance for comparison purposes. The lines of evidence with SCS approach resulted in a 19% to 43% reduction in total number of samples necessary for clearance (see Table 3.6). The reduction depended upon the building scenario, as well as the level of percent clean criteria. A sensitivity analysis was also performed showing how changing the estimated likelihoods of stratum remaining unacceptable affect the number

Electronically rotated and translated field-free line generation for open bore magnetic particle imaging.

Science.gov (United States)

Top, Can Barış; Ilbey, Serhat; Güven, Hüseyin Emre

2017-12-01

We propose a coil arrangement for open bore field-free line (FFL) magnetic particle imaging (MPI) system, which is suitable for accessing the subject from the sides. The purpose of this study is twofold, to show that the FFL can be rotated and translated electronically in a volume of interest with this arrangement and to analyze the current, voltage and power requirements for a 1 T/m gradient human sized scanner for a 200 mm diameter × 200 mm height cylindrical field of view (FOV). We used split coils side by side with alternating current directions to generate a field-free line. Employing two of these coil groups, one of which is rotated 90 degrees with respect to the other, a rotating FFL was generated. We conducted numerical simulations to show the feasibility of this arrangement for three-dimensional (3D) electronical scan of the FFL. Using simulations, we obtained images of a two-dimensional (2D) in silico dot phantom for a human size scanner with system matrix-based reconstruction. Simulations showed that the FFL can be generated and rotated in one plane and can be translated in two axes, allowing for 3D imaging of a large subject with the proposed arrangement. Human sized scanner required 63-215 kW power for the selection field coils to scan the focus inside the FOV. The proposed setup is suitable for FFL MPI imaging with an open bore configuration without the need for mechanical rotation, which is preferable for clinical usage in terms of imaging time and patient access. Further studies are necessary to determine the limitations imposed by peripheral nerve stimulation, and to optimize the system parameters and the sequence design. © 2017 American Association of Physicists in Medicine.

Application of magnetically insulated transmission lines for high current, high voltage electron beam accelerators

International Nuclear Information System (INIS)

Shope, S.L.; Mazarakis, M.G.; Frost, C.A.; Poukey, J.W.; Turman, B.N.

1993-01-01

Self Magnetically Insulated Transmission Lines (MITL) adders have been used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently the authors used a MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r b < 2 cm), 11 to 15 MeV, 50 to 100-kA beams with a small transverse velocity v perpendicular/c = β perpendicular ≤ 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. The authors' success with the MITL technology led them to investigate the application to higher energy accelerator designs. They have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30-50-ns FWHM output pulse

Application of Magnetically Insulated Transmission Lines for high current, high voltage electron beam accelerators

International Nuclear Information System (INIS)

Shope, S.L.; Mazarakis, M.G.; Frost, C.A.; Poukey, J.W.; Turman, B.N.

1991-01-01

Self Magnetically Insulated Transmission Lines (MITL) adders have been used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently we used at MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r ρ < 2 cm), 11 to 15 MeV, 50 to 100-kA beams with a small transverse velocity v perpendicular/c = β perpendicular ≤ 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. Our success with the MITL technology led us to investigate the application to higher energy accelerator designs. We have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30--50 ns FWHM output pulse. 10 refs

Application of magnetically insulated transmission lines for high current, high voltage electron beam accelerators

Science.gov (United States)

Shope, S. L.; Mazarakis, M. G.; Frost, C. A.; Poukey, J. W.; Turman, B. N.

Self Magnetically Insulated Transmission Lines (MITL) adders were used successfully in a number of Sandia accelerators such as HELIA, HERMES III, and SABRE. Most recently we used at MITL adder in the RADLAC/SMILE electron beam accelerator to produce high quality, small radius (r(sub rho) less than 2 cm), 11 - 15 MeV, 50 - 100-kA beams with a small transverse velocity v(perpendicular)/c = beta(perpendicular) less than or equal to 0.1. In RADLAC/SMILE, a coaxial MITL passed through the eight, 2 MV vacuum envelopes. The MITL summed the voltages of all eight feeds to a single foilless diode. The experimental results are in good agreement with code simulations. Our success with the MITL technology led us to investigate the application to higher energy accelerator designs. We have a conceptual design for a cavity-fed MITL that sums the voltages from 100 identical, inductively-isolated cavities. Each cavity is a toroidal structure that is driven simultaneously by four 8-ohm pulse-forming lines, providing a 1-MV voltage pulse to each of the 100 cavities. The point design accelerator is 100 MV, 500 kA, with a 30 - 50 ns FWHM output pulse.

Small scale structure of magnetospheric electron density through on-line tracking of plasma resonances

International Nuclear Information System (INIS)

Higel, B.

1978-01-01

The plasma resonance phenomena observed at fsub(pe), nfsub(ce), and fsub(qn) by the GEOS-1 S-301 relaxation sounder are identified through a pattern recognition software process implemented in a mini-computer which receives on-line the compressed data. First, this processing system distributes in real time fsub(pe) and fsub(ce) measurements to the ground media. Second, it drives and controls automatically the S-301 on-board experiment by sending appropriate telecommands: the tracking of resonances is performed by shortening the frequency sweeps to a narrow range centered on the resonance location. Examples of such tracking sequences are presented, exhibiting sampling rates of the electron density measurements from once every 22s (slowest rate) to once every 86 ms (highest rate available). The results give evidence of the existence of very small scale structures in the magnetospheric density, having characteristic sizes of the order of a few 10 2 m or/and a few 10 -1 s. The relative amplitude of these density fluctuations is typically 1%. Because of satellite spinning, fixed frequency sounding sequences allow to measure in a few seconds the directivity features of the plasma resonance signals. Examples of directional patterns in the plane perpendicular to the geomagnetic field are presented: the electrostatic nature of the waves received at fsub(pe), nfsub(ce), and fsub(qn) being consistent with these patterns, the corresponding k vector orientations become available. The Bernstein modes properties are used to interpret the nfsub(ce) and fsub(qn) results. (Auth.)

Electron-impact excitation of the In+ ion resonance line

International Nuclear Information System (INIS)

Gomonai, A.; OvcharenkO, E.; Imre, A.; Hutych, Yu.

2004-01-01

Full text: Study of the electron-impact excitation of the In + ion is important not only for atomic structure research, but also for applications to astrophysics, analytical techniques and fusion research, as well as for new applications of this ion such as a component of solid state laser media and as a source for an optical frequency standart. The energy dependence of the electron-impact excitation of the In + ion resonance line was studied by spectroscopic method using the crossed-beam technique in the energy range from the threshold up to 300 eV for the following process: e + In + (4d 10 5s 2 ) 1 S 0 e' + In + (4d 10 5s5p) 1 P 0 1 e' + In + (4d 10 5s 2 ) 1 S 0 +h (1) Process (1) includes the direct electron-impact excitation of the 5s5p 1 P 0 1 state from the ground 5s 2 1 S 0 state, as well as the contribution of the cascade transitions and resonance processes: In + (4d 10 5s nln 1 l 1 , 4d 10 5p 2 nl, 4d 9 5s 2 nln 1 l 1 ) In + (4d 10 5s 2 ) 1 S 0 + e' (2) The peculiarity of this investigation is the presence of low lying metastable states and high temperature (T1250K) of atomic vapour. The ions produced in the ion source on the heated tantalum surface were extracted, focused and accelerated by a system of ion optical lenses into a beam (E i = 700eV, I i (11.4)10 -6 A), separated from neutral atoms by means of a 90 deg electrostatic selector and crossed at the right angle by the ribbon electron beam (E e = (7300)eV, Ie = (610)10 -5 A, 0 1/2 (0.40.5)eV) in the collision region (at P 10 -8 Torr) [1]. Radiation observed at 90 deg with respect to the beam intersection plane was spectrally separated by a 70 deg vacuum monochromator (d/dl = 1.7nm/mm) based on the Seya- Namioka scheme and detected by a photomultiplier. The measurements and experimental data processing were realised by means of a PC. The drop of the energy dependence of the excitation cross section obey the E -1 lnE rule specific for the optically allow transitions. A distinct structure in the energy

Comparison of initial damage rates using neutron and electron irradiations

International Nuclear Information System (INIS)

Goldstone, J.A.R.

1978-08-01

The purpose of this experiment was twofold: (1) The number of interstitials that pin dislocations was studied as a function of neutron energy. (2) By comparison with electron irradiations on the sample, a correlation between the predicted and measured numbers of defects was found. All irradiations were performed on the same high purity copper sample. The sample was machined in the form of a cantilever beam with a flexural resonant frequency of 770 Hz. Changes in Young's modulus at constant strain amplitude were monitored continuously through changes in the resonant frequency of the sample. These changes in the modulus can be related to the number of pinning points added to dislocation lines, which are in turn related to the number of free interstitials produced. Neutron energy dependence experiments were done from 2 to 24 MeV on the copper sample and at 14 MeV on a gold sample. By equating pinning rates from electron and neutron irradiations and using the free interstitial production rate obtained from electron irradiations, an estimate of the free interstitial production cross section for neutrons of 2 to 24 MeV was made

Modelling the line shape of very low energy peaks of positron beam induced secondary electrons measured using a time of flight spectrometer

International Nuclear Information System (INIS)

Fairchild, A J; Chirayath, V A; Gladen, R W; Chrysler, M D; Koymen, A R; Weiss, A H

2017-01-01

In this paper, we present results of numerical modelling of the University of Texas at Arlington’s time of flight positron annihilation induced Auger electron spectrometer (UTA TOF-PAES) using SIMION® 8.1 Ion and Electron Optics Simulator. The time of flight (TOF) spectrometer measures the energy of electrons emitted from the surface of a sample as a result of the interaction of low energy positrons with the sample surface. We have used SIMION® 8.1 to calculate the times of flight spectra of electrons leaving the sample surface with energies and angles dispersed according to distribution functions chosen to model the positron induced electron emission process and have thus obtained an estimate of the true electron energy distribution. The simulated TOF distribution was convolved with a Gaussian timing resolution function and compared to the experimental distribution. The broadening observed in the simulated TOF spectra was found to be consistent with that observed in the experimental secondary electron spectra of Cu generated as a result of positrons incident with energy 1.5 eV to 901 eV, when a timing resolution of 2.3 ns was assumed. (paper)

SLIA beam line design

International Nuclear Information System (INIS)

Petillo, J.; Chernin, D.; Kostas, C.; Mondelli, A.

1990-01-01

The Spiral Line Induction Accelerator (SLIA) is a multi-kiloampere compact electron accelerator. It uses linear induction accelerator modules on the straight sections of a racetrack spiral, with strong-focusing bends to recirculate the electrons. The strong focusing is provided by stellarator windings on the bends. Stellarator coils are used to provide the strong focusing on the bends. The matching of the electron beam from a diode through a series of accelerator modules and stellarator bends is a major issue in the design of this accelerator. The beam line design for a proof-of-concept SLIA experiment (10 kA, 7 MeV) to be carried out at Pulse Sciences, Inc. will be presented. The design will demonstrate beam matching from element to element in the focusing system, the design of an achromatic bend, and the requirements for avoiding collective instabilities

Samples and Sampling Protocols for Scientific Investigations | Joel ...

African Journals Online (AJOL)

... from sampling, through sample preparation, calibration to final measurement and reporting. This paper, therefore offers useful information on practical guidance on sampling protocols in line with best practice and international standards. Keywords: Sampling, sampling protocols, chain of custody, analysis, documentation ...

A large sample of Kohonen-selected SDSS quasars with weak emission lines: selection effects and statistical properties

Science.gov (United States)

Meusinger, H.; Balafkan, N.

2014-08-01

Aims: A tiny fraction of the quasar population shows remarkably weak emission lines. Several hypotheses have been developed, but the weak line quasar (WLQ) phenomenon still remains puzzling. The aim of this study was to create a sizeable sample of WLQs and WLQ-like objects and to evaluate various properties of this sample. Methods: We performed a search for WLQs in the spectroscopic data from the Sloan Digital Sky Survey Data Release 7 based on Kohonen self-organising maps for nearly 105 quasar spectra. The final sample consists of 365 quasars in the redshift range z = 0.6 - 4.2 (z¯ = 1.50 ± 0.45) and includes in particular a subsample of 46 WLQs with equivalent widths WMg iiattention was paid to selection effects. Results: The WLQs have, on average, significantly higher luminosities, Eddington ratios, and accretion rates. About half of the excess comes from a selection bias, but an intrinsic excess remains probably caused primarily by higher accretion rates. The spectral energy distribution shows a bluer continuum at rest-frame wavelengths ≳1500 Å. The variability in the optical and UV is relatively low, even taking the variability-luminosity anti-correlation into account. The percentage of radio detected quasars and of core-dominant radio sources is significantly higher than for the control sample, whereas the mean radio-loudness is lower. Conclusions: The properties of our WLQ sample can be consistently understood assuming that it consists of a mix of quasars at the beginning of a stage of increased accretion activity and of beamed radio-quiet quasars. The higher luminosities and Eddington ratios in combination with a bluer spectral energy distribution can be explained by hotter continua, i.e. higher accretion rates. If quasar activity consists of subphases with different accretion rates, a change towards a higher rate is probably accompanied by an only slow development of the broad line region. The composite WLQ spectrum can be reasonably matched by the

Bayesian modeling of JET Li-BES for edge electron density profiles using Gaussian processes

Science.gov (United States)

Kwak, Sehyun; Svensson, Jakob; Brix, Mathias; Ghim, Young-Chul; JET Contributors Collaboration

2015-11-01

A Bayesian model for the JET lithium beam emission spectroscopy (Li-BES) system has been developed to infer edge electron density profiles. The 26 spatial channels measure emission profiles with ~15 ms temporal resolution and ~1 cm spatial resolution. The lithium I (2p-2s) line radiation in an emission spectrum is calculated using a multi-state model, which expresses collisions between the neutral lithium beam atoms and the plasma particles as a set of differential equations. The emission spectrum is described in the model including photon and electronic noise, spectral line shapes, interference filter curves, and relative calibrations. This spectral modeling gets rid of the need of separate background measurements for calculating the intensity of the line radiation. Gaussian processes are applied to model both emission spectrum and edge electron density profile, and the electron temperature to calculate all the rate coefficients is obtained from the JET high resolution Thomson scattering (HRTS) system. The posterior distributions of the edge electron density profile are explored via the numerical technique and the Markov chain Monte Carlo (MCMC) samplings. See the Appendix of F. Romanelli et al., Proceedings of the 25th IAEA Fusion Energy Conference 2014, Saint Petersburg, Russia.

A Multi-Sample Cs-Sputter Negative Ion Source

International Nuclear Information System (INIS)

Alton, G.D.; Ball, J.A.; Bao, Y.; Cui, B.; Reed, C.A.; Williams, C.

1998-01-01

A multi-sample Cs sputter negative-ion source, equipped with a conical-geometry, W-surface-ionizer has been designed and fabricated that permits sample changes without disruption of on-line accelerator operation. Sample changing is effected by actuating an electro-pneumatic control system located at ground potential that drives an air-motor-driven sample-indexing-system mounted at high voltage; this arrangement avoids complications associated with indexing mechanisms that rely on electronic power-supplies located at high potential. In-beam targets are identified by LED indicator lights derived from a fiber-optic, Gray-code target-position sensor. Aspects of the overall source design and details of the indexing mechanism along with operational parameters, ion optics. intensities, and typical emittances for a variety of negative-ion species will be presented in this report

A Multi-Sample Cs-Sputter Negative Ion Source

Energy Technology Data Exchange (ETDEWEB)

Alton, G.D.; Ball, J.A.; Bao, Y.; Cui, B.; Reed, C.A.; Williams, C.

1998-10-05

A multi-sample Cs sputter negative-ion source, equipped with a conical-geometry, W-surface-ionizer has been designed and fabricated that permits sample changes without disruption of on-line accelerator operation. Sample changing is effected by actuating an electro-pneumatic control system located at ground potential that drives an air-motor-driven sample-indexing-system mounted at high voltage; this arrangement avoids complications associated with indexing mechanisms that rely on electronic power-supplies located at high potential. In-beam targets are identified by LED indicator lights derived from a fiber-optic, Gray-code target-position sensor. Aspects of the overall source design and details of the indexing mechanism along with operational parameters, ion optics. intensities, and typical emittances for a variety of negative-ion species will be presented in this report.

Monitoring of an esterification reaction by on-line direct liquid sampling mass spectrometry and in-line mid infrared spectrometry with an attenuated total reflectance probe

International Nuclear Information System (INIS)

Owen, Andrew W.; McAulay, Edith A.J.; Nordon, Alison; Littlejohn, David; Lynch, Thomas P.; Lancaster, J. Steven; Wright, Robert G.

2014-01-01

Highlights: • High efficiency thermal vaporiser designed and used for on-line reaction monitoring. • Concentration profiles of all reactants and products obtained from mass spectra. • By-product formed from the presence of an impurity detected by MS but not MIR. • Mass spectrometry can detect trace and bulk components unlike molecular spectrometry. - Abstract: A specially designed thermal vaporiser was used with a process mass spectrometer designed for gas analysis to monitor the esterification of butan-1-ol and acetic anhydride. The reaction was conducted at two scales: in a 150 mL flask and a 1 L jacketed batch reactor, with liquid delivery flow rates to the vaporiser of 0.1 and 1.0 mL min −1 , respectively. Mass spectrometry measurements were made at selected ion masses, and classical least squares multivariate linear regression was used to produce concentration profiles for the reactants, products and catalyst. The extent of reaction was obtained from the butyl acetate profile and found to be 83% and 76% at 40 °C and 20 °C, respectively, at the 1 L scale. Reactions in the 1 L reactor were also monitored by in-line mid-infrared (MIR) spectrometry; off-line gas chromatography (GC) was used as a reference technique when building partial least squares (PLS) multivariate calibration models for prediction of butyl acetate concentrations from the MIR spectra. In validation experiments, good agreement was achieved between the concentration of butyl acetate obtained from in-line MIR spectra and off-line GC. In the initial few minutes of the reaction the profiles for butyl acetate derived from on-line direct liquid sampling mass spectrometry (DLSMS) differed from those of in-line MIR spectrometry owing to the 2 min transfer time between the reactor and mass spectrometer. As the reaction proceeded, however, the difference between the concentration profiles became less noticeable. DLSMS had advantages over in-line MIR spectrometry as it was easier to generate

Photographs of quantized vortex lines in rotating superfluid helium

International Nuclear Information System (INIS)

Williams, G.A.

1974-01-01

The spatial positions of quantized vortex lines in rotating He II have been determined using a photographic technique. Electrons are trapped on the vortices and then extracted through the liquid surface and accelerated into a phosphor screen. The light from the phosphor is transmitted to room temperature with coherent fiber optics and photographed with an image intensifier camera. Photographs taken with pure 4 He at T = 0.3 K were complete blurs. These blurs are attributed to nonequilibrium motion of the vortices, arising from the lack of normal fluid damping at this temperature. To resolve the individual vortex lines it was found necessary to add 3 He to the 4 He sample to damp the vortex motion. Photographs are presented for 3 He concentrations up to 1.6 percent. The number of vortices visible varies linearly with rotation speed, but is only about one-half the number expected from theory. The vortex lines in the apparatus were not observed to form a stable array

X-ray photoelectron microscope with a compact x-ray source generated by line-focused laser irradiation

International Nuclear Information System (INIS)

Yamaguchi, N.; Okamoto, Y.; Hara, T.; Takahashi, Z.; Nishimura, Y.; Sakata, A.; Watanabe, K.; Azuma, H.

2004-01-01

Full text: A laboratory-sized microscopic system of x-ray photoelectrons has been developing using a compact x-ray source produced by line-focused laser irradiation. The system is a scanning type photoelectron microscope where x-ray beam is micro-focused via a Schwartzschild optics. A compact laser-plasma x-ray source has been developed with a YAG laser system, a line-focus lens system, a tape-target driving system and a debris prevention system, that was operated at repetition rate of 10 Hz or 50 Hz. X-rays were delivered along line plasma whose length was 0.6 to 11 mm with higher intensity than that from a point-focused source. Because the transition line of Al V (13.1 nm) was prominent in the soft x-ray spectrum when the Al tape target irradiated at the lower power density of 10 11 W/cm 2 , the 13.1 nm x-ray was used as an excitation source. The Schwartzschild optics was set on the beamline at a distance about 1 m from the source, which was coated with Mo/Si multilayers for 13.1 nm x-ray. The designed demagnification is 224 that was confirmed in the previous experiment. Therefore, an x-ray micro spot of sub-micron size can be formed on a sample surface when the source size is less than about 0.2 mm. Samples were set on a two-axis high-precision piezo stage mounted to a four-axis manipulator. The electron energy analyzer was a spherical capacitor analyzer with mean diameter of 279.4 mm. The electron detector was a microchannel plate (MCP) with a phosphor screen and the optical image of electrons on the exit plane of the analyzer was taken and recorded by using an ultra low dark noise CCD camera, that was suited for detection of vast photoelectrons excited by x-ray pulse of ns-order duration. We performed spatial resolution test measurements by using a GaAs wafer coated with photo-resist that formed a stripe pattern. The spatial resolution less than 3 micron has been obtained from the variation of As 3d electron intensity along the position of the GaAs sample

Characterization of electron microscopes with binary pseudo-random multilayer test samples

Science.gov (United States)

Yashchuk, Valeriy V.; Conley, Raymond; Anderson, Erik H.; Barber, Samuel K.; Bouet, Nathalie; McKinney, Wayne R.; Takacs, Peter Z.; Voronov, Dmitriy L.

2011-09-01

Verification of the reliability of metrology data from high quality X-ray optics requires that adequate methods for test and calibration of the instruments be developed. For such verification for optical surface profilometers in the spatial frequency domain, a modulation transfer function (MTF) calibration method based on binary pseudo-random (BPR) gratings and arrays has been suggested [1,2] and proven to be an effective calibration method for a number of interferometric microscopes, a phase shifting Fizeau interferometer, and a scatterometer [5]. Here we describe the details of development of binary pseudo-random multilayer (BPRML) test samples suitable for characterization of scanning (SEM) and transmission (TEM) electron microscopes. We discuss the results of TEM measurements with the BPRML test samples fabricated from a WiSi 2/Si multilayer coating with pseudo-randomly distributed layers. In particular, we demonstrate that significant information about the metrological reliability of the TEM measurements can be extracted even when the fundamental frequency of the BPRML sample is smaller than the Nyquist frequency of the measurements. The measurements demonstrate a number of problems related to the interpretation of the SEM and TEM data. Note that similar BPRML test samples can be used to characterize X-ray microscopes. Corresponding work with X-ray microscopes is in progress.

Characterization of electron microscopes with binary pseudo-random multilayer test samples

International Nuclear Information System (INIS)

Yashchuk, Valeriy V.; Conley, Raymond; Anderson, Erik H.; Barber, Samuel K.; Bouet, Nathalie; McKinney, Wayne R.; Takacs, Peter Z.; Voronov, Dmitriy L.

2011-01-01

Verification of the reliability of metrology data from high quality X-ray optics requires that adequate methods for test and calibration of the instruments be developed. For such verification for optical surface profilometers in the spatial frequency domain, a modulation transfer function (MTF) calibration method based on binary pseudo-random (BPR) gratings and arrays has been suggested and proven to be an effective calibration method for a number of interferometric microscopes, a phase shifting Fizeau interferometer, and a scatterometer [5]. Here we describe the details of development of binary pseudo-random multilayer (BPRML) test samples suitable for characterization of scanning (SEM) and transmission (TEM) electron microscopes. We discuss the results of TEM measurements with the BPRML test samples fabricated from a WiSi 2 /Si multilayer coating with pseudo-randomly distributed layers. In particular, we demonstrate that significant information about the metrological reliability of the TEM measurements can be extracted even when the fundamental frequency of the BPRML sample is smaller than the Nyquist frequency of the measurements. The measurements demonstrate a number of problems related to the interpretation of the SEM and TEM data. Note that similar BPRML test samples can be used to characterize X-ray microscopes. Corresponding work with X-ray microscopes is in progress.

Two-dimensional distribution of electron temperature in ergodic layer of LHD measured from line intensity ratio of CIV and NeVIII

International Nuclear Information System (INIS)

Wang, Erhui; Morita, Shigeru; Goto, Motoshi; Murakami, Izumi; Oishi, Tetsutarou; Dong, Chunfeng

2013-01-01

Two-dimensional distribution of impurity lines emitted from ergodic layer with stochastic magnetic field lines in Large Helical Device (LHD) has been observed using a space-resolved extreme ultraviolet (EUV) spectrometer. The two-dimensional electron temperature distribution in the ergodic layer is successfully measured using the line intensity ratio of Li-like NeVIII 2s-3p ( 2 S 1/2 - 2 P 3/2 : 88.09 Å, 2 S 1/2 - 2 P 1/2 : 88.13 Å) to 2p-3s ( 2 P 1/2 - 2 S 1/2 : 102.91 Å, 2 P 3/2 - 2 S 1/2 : 103.09 Å) transitions emitted from radial location near Last Closed Flux Surface (LCFS). The intensity ratio analyzed with ADAS code shows no dependence on the electron density below 10 14 cm -3 . The result indicates a little higher temperature, i.e., 220 eV, in the poloidal location at high-field side near helical coils called O-point compared to the temperature near X-point, i.e., 170 eV. The electron temperature profile is also measured at the edge boundary of ergodic layer using the line intensity ratio of Li-like CIV 2p-3d ( 2 P 1/2 - 2 D 3/2 : 384.03 Å, 2 P 3/2 - 2 D 5/2 : 384.18 Å) to 2p-3s ( 2 P 1/2 - 2 S 1/2 : 419.53 Å, 2 P 3/2 - 2 S 1/2 : 419.71 Å) transitions. The intensity ratios analyzed with CHIANTI, ADAS and T.Kawachi codes show a slightly higher temperature near O-point, i.e., 25 eV for CHIANTI, 21 eV for ADAS and 11 eV for T.Kawachi's codes, compared to the temperature at X-point, i.e., 15 - 21 eV for CHIANTI, 9 - 15 eV for ADAS and 6 - 9 eV for T.Kawachi codes. It suggests that the transport coefficient in the ergodic layer is varied with three-dimensional structure. (author)

Determination of dislocation density by electron backscatter diffraction and X-ray line profile analysis in ferrous lath martensite

International Nuclear Information System (INIS)

Berecz, Tibor; Jenei, Péter; Csóré, András; Lábár, János; Gubicza, Jenő

2016-01-01

The microstructure and the dislocation density in as-quenched ferrous lath martensite were studied by different methods. The blocks, packets and variants formed due to martensitic transformation were identified and their sizes were determined by electron backscatter diffraction (EBSD). Concomitant transmission electron microscopy (TEM) investigation revealed that the laths contain subgrains with the size between 50 and 100 nm. A novel evaluation procedure of EBSD images was elaborated for the determination of the density and the space distribution of geometrically necessary dislocations from the misorientation distribution. The total dislocation density obtained by X-ray diffraction line profile analysis was in good agreement with the value determined by EBSD, indicating that the majority of dislocations formed due to martensitic transformation during quenching are geometrically necessary dislocations.

Scanning electron microscope autoradiography of critical point dried biological samples

International Nuclear Information System (INIS)

Weiss, R.L.

1980-01-01

A technique has been developed for the localization of isotopes in the scanning electron microscope. Autoradiographic studies have been performed using a model system and a unicellular biflagellate alga. One requirement of this technique is that all manipulations be carried out on samples that are maintained in a liquid state. Observations of a source of radiation ( 125 I-ferritin) show that the nuclear emulsion used to detect radiation is active under these conditions. Efficiency measurement performed using 125 I-ferritin indicate that 125 I-SEM autoradiography is an efficient process that exhibits a 'dose dependent' response. Two types of labeling methods were used with cells, surface labeling with 125 I and internal labeling with 3 H. Silver grains appeared on labeled cells after autoradiography, removal of residual gelatin and critical point drying. The location of grains was examined on a flagellated green alga (Chlamydomonas reinhardi) capable of undergoing cell fusion. Fusion experiments using labeled and unlabeled cells indicate that 1. Labeling is specific for incorporated radioactivity; 2. Cell surface structure is preserved in SEM autoradiographs and 3. The technique appears to produce reliable autoradiographs. Thus scanning electron microscope autoradiography should provide a new and useful experimental approach

Authentication of M14 melanoma cell line proves misidentification of MDA‐MB‐435 breast cancer cell line

Science.gov (United States)

Korch, Christopher; Hall, Erin M.; Dirks, Wilhelm G.; Ewing, Margaret; Faries, Mark; Varella‐Garcia, Marileila; Robinson, Steven; Storts, Douglas; Turner, Jacqueline A.; Wang, Ying; Burnett, Edward C.; Healy, Lyn; Kniss, Douglas; Neve, Richard M.; Nims, Raymond W.; Reid, Yvonne A.; Robinson, William A.

2017-01-01

A variety of analytical approaches have indicated that melanoma cell line UCLA‐SO‐M14 (M14) and breast carcinoma cell line MDA‐MB‐435 originate from a common donor. This indicates that at some point in the past, one of these cell lines became misidentified, meaning that it ceased to correspond to the reported donor and instead became falsely identified (through cross‐contamination or other means) as a cell line from a different donor. Initial studies concluded that MDA‐MB‐435 was the misidentified cell line and M14 was the authentic cell line, although contradictory evidence has been published, resulting in further confusion. To address this question, we obtained early samples of the melanoma cell line (M14), a lymphoblastoid cell line from the same donor (ML14), and donor serum preserved at the originator's institution. M14 samples were cryopreserved in December 1975, before MDA‐MB‐435 cells were established in culture. Through a series of molecular characterizations, including short tandem repeat (STR) profiling and cytogenetic analysis, we demonstrated that later samples of M14 and MDA‐MB‐435 correspond to samples of M14 frozen in 1975, to the lymphoblastoid cell line ML14, and to the melanoma donor's STR profile, sex and blood type. This work demonstrates conclusively that M14 is the authentic cell line and MDA‐MB‐435 is misidentified. With clear provenance information and authentication testing of early samples, it is possible to resolve debates regarding the origins of problematic cell lines that are widely used in cancer research. PMID:28940260

An investigation of the performance of an electronic in-line pump system for diesel engines

Science.gov (United States)

Fan, Li-Yun; Zhu, Yuan-Xian; Long, Wu-Qiang; Ma, Xiu-Zhen; Xue, Ying-Ying

2008-12-01

WIT Electronic Fuel System Co., Ltd. has developed a new fuel injector, the Electronic In-line Pump (EIP) system, designed to meet China’s diesel engine emission and fuel economy regulations. It can be used on marine diesel engines and commercial vehicle engines through different EIP systems. A numerical model of the EIP system was built in the AMESim environment for the purpose of creating a design tool for engine application and system optimization. The model was used to predict key injection characteristics under different operating conditions, such as injection pressure, injection rate, and injection duration. To validate these predictions, experimental tests were conducted under the conditions that were modeled. The results were quite encouraging and in agreement with model predictions. Additional experiments were conducted to study the injection characteristics of the EIP system. These results show that injection pressure and injection quantity are insensitive to injection timing variations, this is due to the design of the constant velocity cam profile. Finally, injection quantity and pressure vs. pulse width at different cam speeds are presented, an important injection characteristic for EIP system calibration.

Determination of drugs in biological fluids by high-performance liquid chromatography with on-line sample processing.

Science.gov (United States)

Oertel, R; Richter, K; Gramatté, T; Kirch, W

1998-02-27

An automated two column HPLC system with the new packing material LiChrospher RP-18 ADS (alkyl-diol-silica) was tested for the determination of several drugs and metabolites (talinolol, celiprolol, metoprolol, oxprenolol, triamterene, trimethoprim, tiracizine, articaine, detajmium, ajmaline, lamotrigine) in various biological fluids (serum, urine, intestinal aspirates, supernatants of cell cultures and supernatants after protein denaturation). The method allows the direct injection of biological fluids into a reversed-phase HPLC system and on-line clean-up and sample enrichment by a column-switching technique. Precision, accuracy and sensitivity were similar to conventional assays as described in the literature. With this new method it was possible to measure drug concentrations in various biological fluids without changing the sample preparation procedure. In some cases an additional sample preparation like protein denaturation or solid-phase extraction was advantageous to enhance the sensitivity of the method and the life-time of the ADS column.

Signature of electron-phonon interaction in high temperature superconductors

Directory of Open Access Journals (Sweden)

Vinod Ashokan

2011-09-01

Full Text Available The theory of thermal conductivity of high temperature superconductors (HTS based on electron and phonon line width (life times formulation is developed with Quantum dynamical approach of Green's function. The frequency line width is observed as an extremely sensitive quantity in the transport phenomena of HTS as a collection of large number of scattering processes. The role of resonance scattering and electron-phonon interaction processes is found to be most prominent near critical temperature. The theory successfully explains the spectacular behaviour of high Tc superconductors in the vicinity of transition temperature. A successful agreement between theory and experiment has been obtained by analyzing the thermal conductivity data for the sample La1.8Sr0.2CuO4 in the temperature range 0 − 200K. The theory is equally and successfully applicable to all other high Tc superconductors.

Multiple double cross-section transmission electron microscope sample preparation of specific sub-10 nm diameter Si nanowire devices.

Science.gov (United States)

Gignac, Lynne M; Mittal, Surbhi; Bangsaruntip, Sarunya; Cohen, Guy M; Sleight, Jeffrey W

2011-12-01

The ability to prepare multiple cross-section transmission electron microscope (XTEM) samples from one XTEM sample of specific sub-10 nm features was demonstrated. Sub-10 nm diameter Si nanowire (NW) devices were initially cross-sectioned using a dual-beam focused ion beam system in a direction running parallel to the device channel. From this XTEM sample, both low- and high-resolution transmission electron microscope (TEM) images were obtained from six separate, specific site Si NW devices. The XTEM sample was then re-sectioned in four separate locations in a direction perpendicular to the device channel: 90° from the original XTEM sample direction. Three of the four XTEM samples were successfully sectioned in the gate region of the device. From these three samples, low- and high-resolution TEM images of the Si NW were taken and measurements of the NW diameters were obtained. This technique demonstrated the ability to obtain high-resolution TEM images in directions 90° from one another of multiple, specific sub-10 nm features that were spaced 1.1 μm apart.

Multipactor threshold calculation of coaxial transmission lines in microwave applications with nonstationary statistical theory

International Nuclear Information System (INIS)

Lin, S.; Li, Y.; Liu, C.; Wang, H.; Zhang, N.; Cui, W.; Neuber, A.

2015-01-01

This paper presents a statistical theory for the initial onset of multipactor breakdown in coaxial transmission lines, taking both the nonuniform electric field and random electron emission velocity into account. A general numerical method is first developed to construct the joint probability density function based on the approximate equation of the electron trajectory. The nonstationary dynamics of the multipactor process on both surfaces of coaxial lines are modelled based on the probability of various impacts and their corresponding secondary emission. The resonant assumption of the classical theory on the independent double-sided and single-sided impacts is replaced by the consideration of their interaction. As a result, the time evolutions of the electron population for exponential growth and absorption on both inner and outer conductor, in response to the applied voltage above and below the multipactor breakdown level, are obtained to investigate the exact mechanism of multipactor discharge in coaxial lines. Furthermore, the multipactor threshold predictions of the presented model are compared with experimental results using measured secondary emission yield of the tested samples which shows reasonable agreement. Finally, the detailed impact scenario reveals that single-surface multipactor is more likely to occur with a higher outer to inner conductor radius ratio

Cable line engineering

International Nuclear Information System (INIS)

Jang, Hak Sin; Kim, Sin Yeong

1998-02-01

This book is about cable line engineering. It is comprised of nine chapters, which deals with summary of cable communication such as way, process of cable communication and optical communication, Line constant of transmission on primary constant, reflection and crosstalk, communication cable line of types like flat cable, coaxial cable and loaded cable, Install of communication line with types and facility of aerial line, construction method of communication line facility, Measurement of communication line, Carrier communication of summary, PCM communication with Introduction, regeneration relay system sampling and quantization and Electric communication service and general information network with mobile communication technique and satellite communication system.

Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies

Science.gov (United States)

Rakshit, Suvendu; Stalin, C. S.

2017-06-01

We studied the optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z anti-correlated with Fe II strength but correlated with the width of the Hβ line. The well-known anti-correlation of variability-luminosity and the variability-Eddington ratio is present in our data. Among the radio-loud sample, variability amplitude is found to be correlated with radio-loudness and radio-power, suggesting that jets also play an important role in the OV in radio-loud objects, in addition to the Eddington ratio, which is the main driving factor of OV in radio-quiet sources.

Spin helical states and spin transport of the line defect in silicene lattice

Energy Technology Data Exchange (ETDEWEB)

Yang, Mou; Chen, Dong-Hai; Wang, Rui-Qiang [Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006 (China); Bai, Yan-Kui, E-mail: ykbai@semi.ac.cn [College of Physical Science and Information Engineering and Hebei Advance Thin Films Laboratory, Hebei Normal University, Shijiazhuang, Hebei 050024 (China)

2015-02-06

We investigated the electronic structure of a silicene-like lattice with a line defect under the consideration of spin–orbit coupling. In the bulk energy gap, there are defect related bands corresponding to spin helical states localized beside the defect line: spin-up electrons flow forward on one side near the line defect and move backward on the other side, and vice versa for spin-down electrons. When the system is subjected to random distribution of spin-flipping scatterers, electrons suffer much less spin-flipped scattering when they transport along the line defect than in the bulk. An electric gate above the line defect can tune the spin-flipped transmission, which makes the line defect as a spin-controllable waveguide. - Highlights: • Band structure of silicene with a line defect. • Spin helical states around the line defect and their probability distribution features. • Spin transport along the line defect and that in the bulk silicene.

Liquid sampling-atmospheric pressure glow discharge as a secondary excitation source: Assessment of plasma characteristics

Energy Technology Data Exchange (ETDEWEB)

Manard, Benjamin T. [Department of Chemistry, Clemson University, Clemson, SC 29634 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Gonzalez, Jhanis J. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Sarkar, Arnab [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Fuel Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Dong, Meirong; Chirinos, Jose; Mao, Xianglei; Russo, Richard E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Marcus, R. Kenneth [Department of Chemistry, Clemson University, Clemson, SC 29634 (United States)

2014-04-01

The liquid sampling-atmospheric pressure glow discharge (LS-APGD) has been assessed as a secondary excitation source with a parametric evaluation regarding carrier gas flow rate, applied current, and electrode distance. With this parametric evaluation, plasma optical emission was monitored in order to obtain a fundamental understanding with regards to rotational temperature (T{sub rot}), excitation temperature (T{sub exc}), electron number density (n{sub e}), and plasma robustness. Incentive for these studies is not only for a greater overall fundamental knowledge of the APGD, but also in instrumenting a secondary excitation/ionization source following laser ablation (LA). Rotational temperatures were determined through experimentally fitting of the N{sub 2} and OH molecular emission bands while atomic excitation temperatures were calculated using a Boltzmann distribution of He and Mg atomic lines. The rotational and excitation temperatures were determined to be ∼ 1000 K and ∼ 2700 K respectively. Electron number density was calculated to be on the order of ∼ 3 × 10{sup 15} cm{sup −3} utilizing Stark broadening effects of the Hα line of the Balmer series and a He I transition. In addition, those diagnostics were performed introducing magnesium (by solution feed and laser ablation) into the plasma in order to determine any perturbation under heavy matrix sampling. The so-called plasma robustness factor, derived by monitoring Mg II/Mg I emission ratios, is also employed as a reflection of potential perturbations in microplasma energetics across the various operation conditions and sample loadings. While truly a miniaturized source (< 1 mm{sup 3} volume), the LS-APGD is shown to be quite robust with plasma characteristics and temperatures being unaffected upon introduction of metal species, whether by liquid or laser ablation sample introduction. - Highlights: • Liquid sampling-atmospheric pressure glow discharge (LS-APGD) • LS-APGD as a secondary

Analysis of microcontaminants in aqueous samples by fully automated on-line solid-phase extraction-gas chromatography-mass selective detection.

NARCIS (Netherlands)

Louter, A.J.H.; van Beekvelt, C.A.; Cid Montanes, P.; Slobodník, J.; Vreuls, J.J.; Brinkman, U.A.T.

1996-01-01

The trace-level analysis of unknown organic pollutants in water requires the use of fast and sensitive methods which also provide structural information. In the present study, an on-line technique was used which combines sample preparation by means of solid-phase extraction (SPE) on a small

Characterizing string-of-pearls colloidal silica by multidetector hydrodynamic chromatography and comparison to multidetector size-exclusion chromatography, off-line multiangle static light scattering, and transmission electron microscopy.

Science.gov (United States)

Brewer, Amandaa K; Striegel, André M

2011-04-15

multidetector HDC results were also comparable to those obtained by transmission electron microscopy (TEM). Unlike off-line MALS or TEM, however, multidetector HDC is able to provide complete particle analysis based on the molar mass, size, shape, and compactness and their distributions for the entire sample population in less than 20 min. © 2011 American Chemical Society

The problem of large samples. An activation analysis study of electronic waste material

International Nuclear Information System (INIS)

Segebade, C.; Goerner, W.; Bode, P.

2007-01-01

Large-volume instrumental photon activation analysis (IPAA) was used for the investigation of shredded electronic waste material. Sample masses from 1 to 150 grams were analyzed to obtain an estimate of the minimum sample size to be taken to achieve a representativeness of the results which is satisfactory for a defined investigation task. Furthermore, the influence of irradiation and measurement parameters upon the quality of the analytical results were studied. Finally, the analytical data obtained from IPAA and instrumental neutron activation analysis (INAA), both carried out in a large-volume mode, were compared. Only parts of the values were found in satisfactory agreement. (author)

Determination of plasma temperature and electron density in river sediment plasma using calibration-free laser-induced breakdown spectroscopy

International Nuclear Information System (INIS)

Austria, Elmer S. Jr.; Lamorena-Lim, Rheo B.

2015-01-01

Calibration-free laser-induced breakdown spectroscopy (CF-LIBS) technique is an approach used to quantitatively measure elemental composition of samples without the use of standard reference materials (SRMs). Due to the unavailability of most SRMs for specific samples, the CF-LIBS approach is steadily becoming more prevalent. CF-LIBS also minimizes interferences from the sample matrix by accounting spectral line intensifies of different elements. The first part of the CF-LIBS algorithm is the calculation of plasma temperature and electron density of the sample while the second part deals with the self-absorption correction and quantitative elemental analysis. In this study, the precursor parameters for the algorithm - plasma temperature and electron density - were measured through the neutral atom and ion line emissions of Fe and Cu in the time window of 0.1 to 10 μs. Plasma from river sediment samples were produced by a 1064 nm nanosecond pulsed Nd:YAG laser at atmospheric pressure. The plasma temperature and electron density were calculated from the Boltzmann plot and Saha-Boltzmann equation methods, respectively. These precursor parameters can be used in calculating the time window wherein the plasma is optically thin at local thermodynamic equilibrium (LTE) and for quantitative multi-elemental analysis. (author)

Purity, adulteration and price of drugs bought on-line versus off-line in the Netherlands.

Science.gov (United States)

van der Gouwe, Daan; Brunt, Tibor M; van Laar, Margriet; van der Pol, Peggy

2017-04-01

On-line drug markets flourish and consumers have high expectations of on-line quality and drug value. The aim of this study was to (i) describe on-line drug purchases and (ii) compare on-line with off-line purchased drugs regarding purity, adulteration and price. Comparison of laboratory analyses of 32 663 drug consumer samples (stimulants and hallucinogens) purchased between January 2013 and January 2016, 928 of which were bought on-line. The Netherlands. Primary outcome measures were (i) the percentage of samples purchased on-line and (ii) the chemical purity of powders (or dosage per tablet); adulteration; and the price per gram, blotter or tablet of drugs bought on-line compared with drugs bought off-line. The proportion of drug samples purchased on-line increased from 1.4% in 2013 to 4.1% in 2015. The frequency varied widely, from a maximum of 6% for controlled, traditional substances [ecstasy tablets, 3,4-methylenedioxy-methamphetamine (MDMA) powder, amphetamine powder, cocaine powder, 4-bromo-2,5-dimethoxyphenethylamine (2C-B) and lysergic acid diethylamide (LSD)] to more than a third for new psychoactive substances (NPS) [4-fluoroamphetamine (4-FA), 5/6-(2-aminopropyl)benzofuran (5/6-APB) and methoxetamine (MXE)]. There were no large differences in drug purity, yet small but statistically significant differences were found for 4-FA (on-line 59% versus off-line 52% purity for 4-FA on average, P = 0.001), MDMA powders (45 versus 61% purity for MDMA, P = 0.02), 2C-B tablets (21 versus 10 mg 2C-B/tablet dosage, P = 0.49) and ecstasy tablets (131 versus 121 mg MDMA/tablet dosage, P = 0.05). The proportion of adulterated samples purchased on-line and off-line did not differ, except for 4-FA powder, being less adulterated on-line (χ 2  = 8.3; P < 0.02). Drug prices were mainly higher on-line, ranging for various drugs from 10 to 23% higher than that of drugs purchased off-line (six of 10 substances: P < 0.05). Dutch drug users increasingly

Influence of the operating parameters and of the sample introduction system on time correlation of line intensities using an axially viewed CCD-based ICP-AES system

Energy Technology Data Exchange (ETDEWEB)

Grotti, Marco, E-mail: grotti@chimica.unige.i [Dipartimento di Chimica e Chimica Industriale, Via Dodecaneso 31, 16146 Genova (Italy); Todoli, Jose Luis [Departamento de Quimica Analitica, Nutricion y Bromatologia, Universidad de Alicante, 03080, Alicante (Spain); Mermet, Jean Michel [Spectroscopy Forever, 01390 Tramoyes (France)

2010-02-15

The influence of the acquisition and operating parameters on time correlation between emission line intensities was investigated using axially viewed inductively coupled plasma-multichannel-based emission spectrometry and various sample introduction systems. It was found that to obtain flicker-noise limited signals, necessary to compensate for time-correlated signal fluctuations by internal standardization, the flicker-noise magnitude of the sample introduction system, the integration time and the emission line intensity had to be considered. The highest correlation between lines was observed for ultrasonic nebulization with desolvatation, the noisiest system among those considered, for which the contribution of the uncorrelated shot-noise was negligible. In contrast, for sample introduction systems characterized by lower flicker-noise levels, shot-noise led to high, non-correlated RSD values, making the internal standard method to be much less efficient. To minimize shot-noise, time correlation was improved by increasing the emission line intensities and the integration time. Improvement in repeatability did not depend only on time correlation, but also on the ratio between the relative standard deviations of the analytical and reference lines. The best signal compensation was obtained when RSD values of the reference and analytical lines were similar, which is usually obtained when the system is flicker-noise limited, while departure from similarity can lead to a degradation of repeatability when using the internal standard method. Moreover, the use of so-called robust plasma conditions, i.e. a high power (1500 W) along with a low carrier gas flow rate (0.8 L/min) improved also the compensation. Finally, high correlation and consequent improvement in repeatability by internal standardization was observed also in the presence of complex matrices (sediment and soil samples), although a matrix-induced degradation of the correlation between lines was generally

Non-equilibrium Modeling of the Fe XVII 3C/3D Line Ratio in an Intense X-Ray Free-Electron Laser Excited Plasma

Science.gov (United States)

Loch, S. D.; Ballance, C. P.; Li, Y.; Fogle, M.; Fontes, C. J.

2015-03-01

Recent measurements using an X-ray Free Electron Laser (XFEL) and an Electron Beam Ion Trap at the Linac Coherent Light Source facility highlighted large discrepancies between the observed and theoretical values for the Fe xvii 3C/3D line intensity ratio. This result raised the question of whether the theoretical oscillator strengths may be significantly in error, due to insufficiencies in the atomic structure calculations. We present time-dependent spectral modeling of this experiment and show that non-equilibrium effects can dramatically reduce the predicted 3C/3D line intensity ratio, compared with that obtained by simply taking the ratio of oscillator strengths. Once these non-equilibrium effects are accounted for, the measured line intensity ratio can be used to determine a revised value for the 3C/3D oscillator strength ratio, giving a range from 3.0 to 3.5. We also provide a framework to narrow this range further, if more precise information about the pulse parameters can be determined. We discuss the implications of the new results for the use of Fe xvii spectral features as astrophysical diagnostics and investigate the importance of time-dependent effects in interpreting XFEL-excited plasmas.

[Analysis of phthalate esters in plastic-packaging bags on-line sample stacking-microemulsion electrokinetic chromatography].

Science.gov (United States)

Xiao, Jia; Huang, Ying; Wang, Minyi; Chen, Guonan

2012-09-01

Two convenient, effective, and reproducible methods using microemulsion electrokinetic chromatography (MEEKC)-normal stacking mode (NSM) and reversed electrode polarity stacking mode (REPSM) were developed for the on-line sample stacking of phthalate esters (PAEs). REPSM coupled with MEEKC increased the sensitivity of 937.5 to 7,143 times for four PAEs compared to the conventional MEEKC. The separating conditions in the MEEKC method were studied, and many factors influencing the two sample stacking processes were investigated in detail. The optimum sample matrices for the two stacking methods were as follows: 30 mmol/L sodium cholate (SC) and 30.0 mmol/L borate (pH 8.5). Additionally, sample injections as large as 3.45 kPa x 40 s and 3.45 kPa x 90 s were applied for NSM-MEEKC and REPSM-MEEKC, respectively. The linear relationship and reproducibility were also examined. Under the optimum conditions, the detection limits (S/N = 3) of the PAEs were in the ranges of 0.021 - 0.33 mg/L and 0.7 - 4 microg/L for NSM-MEEKC and REPSM-MEEKC, respectively. The proposed REPSM-MEEKC has been successfully applied to determine PAEs in plastic-packaging bags, and the spiked recoveries were in the range of 89.1% - 105.6% with satisfactory results.

Analog Electronic Filters Theory, Design and Synthesis

CERN Document Server

Dimopoulos, Hercules G

2012-01-01

Filters are essential subsystems in a huge variety of electronic systems. Filter applications are innumerable; they are used for noise reduction, demodulation, signal detection, multiplexing, sampling, sound and speech processing, transmission line equalization and image processing, to name just a few. In practice, no electronic system can exist without filters. They can be found in everything from power supplies to mobile phones and hard disk drives and from loudspeakers and MP3 players to home cinema systems and broadband Internet connections. This textbook introduces basic concepts and methods and the associated mathematical and computational tools employed in electronic filter theory, synthesis and design.  This book can be used as an integral part of undergraduate courses on analog electronic filters. Includes numerous, solved examples, applied examples and exercises for each chapter. Includes detailed coverage of active and passive filters in an independent but correlated manner. Emphasizes real filter...

Application of electron paramagnetic resonance to identify irradiated soybean

International Nuclear Information System (INIS)

Bhaskar, S.; Behere, Arun; Sharma, Arun

2006-01-01

Full text: Electron paramagnetic resonance spectroscopy was applied to study free radicals in soy bean seed after gamma irradiation and to establish the potential of these radiation induced free radicals as the indicator of the radiation treatment. The radiation doses administered to the samples were 1 to 30 kGy. A stable doublet signal was detected at g = 2.0279 with hyperfine coupling constant of 2.8 mT, produced only by radiolysis. This signal can be used to identify irradiated soy bean seed samples. With the increase of the radiation dose the central line intensity and the intensities of the satellite lines showed almost a linear rise having linear correlation factors of 0.99724 and 0.99996, respectively. Thermal treatment at 373 deg K in air was studied. No line specific to thermolysis was observed. The spectrometer was operated with power 0.253 mW, microwave frequency 9.74 GHz, modulation frequency 100 kHz and scan range 10 mT. To study the stability of the signal, EPR spectra were obtained from the irradiated skin part of soy bean seeds samples following 1 and 90 days of storage after radiation treatment. The two satellite lines of g left = 2.0279 and g right 1.99529 were detected in all samples. This suggests that the signal is associated with a stable radical and therefore, the detection of a particular free radical as a marker of irradiation is proposed

Quenching of exciton luminescence due to impact ionization and mechanisms of electron relaxation in cadmium sulphide

International Nuclear Information System (INIS)

Kagan, V.D.; Karpenko, S.L.; Katilyus, R.

1989-01-01

Quenching of exciton luminescence in the constant electric field in cadmium sulfide at 1.8K, caused by impact ionization of free and delocalization of bound excitons by hot electrons is observed. When the field is increase up to 1 kW/cm continuous transfer from the Taundsen-Shockley law to the Davydov-Wolf one takes place. Among the samples studied pure samples are distinguished by the exciton spectrum, where, as it is shown in the work, the high-energy electrons lose quasipulse, radiating spontaneously piezophonons; in other samples scattering on impurities prevails. Theoretical processing of data on the bound exciton radiation line quenching in the moderate field region presents about 10 -4 values in pure and about 5x10 -6 cm ones in other samples for the 4 MeV energy electron free flight length. So, the optical methods used allowed one to determine high-energy electron relaxation mechanisms, prevailing in CdS at low temperature

The SAMPLE experiment: Parity-violating electron scattering from the proton and deuteron

International Nuclear Information System (INIS)

Pitt, M.; Arrington, J.; Beck, D.; Beise, E.; Candell, E.; Cardman, L.; Carr, R.; Dodson, G.; Dow, K.; Duncan, F.; Farkhondeh, M.; Filippone, B.; Forest, T.; Gao, H.; Korsch, W.; Kowalski, S.; Lung, A.; McKeown, R.; Mohring, R.; Mueller, B.; Napolitano, J.; Simicevic, N.; Terburg, B.; Witkowski, M.

1995-01-01

Recent experimental evidence on nucleon structure has provided indications that some strange quark matrix elements can be comparable to those involving up and down quarks. The SAMPLE experiment will determine the strange magnetic form factor G s M at Q 2 =0.1 (GeV/c) 2 from a measurement of the asymmetry in the scattering of polarized electrons from the proton. The error on the extraction of G s M is ultimately limited by a theoretical uncertainty---the uncertain electroweak hadronic radiative correction to the axial form factor, R T=1 A . To address this issue, the collaboration is also approved to measure the asymmetry in parity-violating quasielastic electron scattering from the deuteron. The combination of the proton and deuteron measurements will yield a value of G s M that is almost completely free of the uncertainty in R T=1 A

An integrated sample pretreatment platform for quantitative N-glycoproteome analysis with combination of on-line glycopeptide enrichment, deglycosylation and dimethyl labeling

Energy Technology Data Exchange (ETDEWEB)

Weng, Yejing; Qu, Yanyan; Jiang, Hao; Wu, Qi [National Chromatographic Research and Analysis Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); University of the Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Lihua, E-mail: lihuazhang@dicp.ac.cn [National Chromatographic Research and Analysis Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Yuan, Huiming [National Chromatographic Research and Analysis Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); Zhou, Yuan [National Chromatographic Research and Analysis Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China); University of the Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Xiaodan; Zhang, Yukui [National Chromatographic Research and Analysis Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

2014-06-23

Highlights: • An integrated platform for quantitative N-glycoproteome analysis was established. • On-line enrichment, deglycosylation and labeling could be achieved within 160 min. • A N{sub 2}-assisted interface was applied to improve the compatibility of the platform. • The platform exhibited improved quantification accuracy, precision and throughput. - Abstract: Relative quantification of N-glycoproteomes shows great promise for the discovery of candidate biomarkers and therapeutic targets. The traditional protocol for quantitative analysis of glycoproteomes is usually off-line performed, and suffers from long sample preparation time, and the risk of sample loss or contamination due to manual manipulation. In this study, a novel integrated sample preparation platform for quantitative N-glycoproteome analysis was established, with combination of online N-glycopeptide capture by a HILIC column, sample buffer exchange by a N{sub 2}-assisted HILIC–RPLC interface, deglycosylation by a hydrophilic PNGase F immobilized enzymatic reactor (hIMER) and solid dimethyl labeling on a C18 precolumn. To evaluate the performance of such a platform, two equal aliquots of immunoglobulin G (IgG) digests were sequentially pretreated, followed by MALDI-TOF MS analysis. The signal intensity ratio of heavy/light (H/L) labeled deglycosylated peptides with the equal aliquots was 1.00 (RSD = 6.2%, n = 3), much better than those obtained by the offline protocol, with H/L ratio as 0.76 (RSD = 11.6%, n = 3). Additionally, the total on-line sample preparation time was greatly shortened to 160 min, much faster than that of offline approach (24 h). Furthermore, such an integrated pretreatment platform was successfully applied to analyze the two kinds of hepatocarcinoma ascites syngeneic cell lines with high (Hca-F) and low (Hca-P) lymph node metastasis rates. For H/L labeled Hca-P lysates with the equal aliquots, 99.6% of log 2 ratios (H/L) of quantified glycopeptides ranged from −1

The recommendation of line-balancing improvement on MCM product line 1 using genetics algorithm and moodie young at XYZ Company, Co.

Science.gov (United States)

Sriwana, I. K.; Marie, I. A.; Mangala, D.

2017-12-01

Kencana Gemilang, Co. is one electronics industry engaging in the manufacture sector. This company manufactures and assembles household electronic products, such as rice cooker, fan, iron, blender, etc. The company deals with an issue of underachievement of an established production target on MCM products line 1. This study aimed to calculate line efficiencies, delay times, and initial line smoothness indexes. The research was carried out by means of depicting a precedence diagram and gathering time data of each work element followed by examination and calculation of standard time as well as line balancing using methods of Moodie Young and Generics Algorithm. Based on results of calculation, better line balancing than the existing initial conditions, i.e. improvement in the line efficiency by 18.39%, deterioration in balanced delay by 28.39%, and deterioration of a smoothness index by 23.85% was obtained.

Electron microscopy and forensic practice

Science.gov (United States)

Kotrlý, Marek; Turková, Ivana

2013-05-01

Electron microanalysis in forensic practice ranks among basic applications used in investigation of traces (latents, stains, etc.) from crime scenes. Applying electron microscope allows for rapid screening and receiving initial information for a wide range of traces. SEM with EDS/WDS makes it possible to observe topography surface and morphology samples and examination of chemical components. Physical laboratory of the Institute of Criminalistics Prague use SEM especially for examination of inorganic samples, rarely for biology and other material. Recently, possibilities of electron microscopy have been extended considerably using dual systems with focused ion beam. These systems are applied mainly in study of inner micro and nanoparticles , thin layers (intersecting lines in graphical forensic examinations, analysis of layers of functional glass, etc.), study of alloys microdefects, creating 3D particles and aggregates models, etc. Automated mineralogical analyses are a great asset to analysis of mineral phases, particularly soils, similarly it holds for cathode luminescence, predominantly colour one and precise quantitative measurement of their spectral characteristics. Among latest innovations that are becoming to appear also at ordinary laboratories are TOF - SIMS systems and micro Raman spectroscopy with a resolution comparable to EDS/WDS analysis (capable of achieving similar level as through EDS/WDS analysis).

Black hole mass estimates and emission-line properties of a sample of redshift z > 6.5 quasars

Energy Technology Data Exchange (ETDEWEB)

De Rosa, Gisella; Peterson, Bradley M.; Frank, Stephan [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Venemans, Bram P.; Decarli, Roberto; Walter, Fabian [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Gennaro, Mario [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Simcoe, Robert A. [MIT-Kavli Center for Astrophysics and Space Research, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Dietrich, Matthias [Department of Physics and Astronomy, Ohio University, Clippinger Lab 251B, Athens, OH 45701 (United States); McMahon, Richard G.; Hewett, Paul C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Mortlock, Daniel J. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London, SW7 2AZ (United Kingdom); Simpson, Chris [Astrophysics Research Institute, Liverpool John Moores University, Liverpool Science Park, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom)

2014-08-01

We present the analysis of optical and near-infrared spectra of the only four z > 6.5 quasars known to date, discovered in the UKIDSS-LAS and VISTA-VIKING surveys. Our data set consists of new Very Large Telescope/X-Shooter and Magellan/FIRE observations. These are the best optical/NIR spectroscopic data that are likely to be obtained for the z > 6.5 sample using current 6-10 m facilities. We estimate the black hole (BH) mass, the Eddington ratio, and the Si IV/C IV, C III]/C IV, and Fe II/Mg II emission-line flux ratios. We perform spectral modeling using a procedure that allows us to derive a probability distribution for the continuum components and to obtain the quasar properties weighted upon the underlying distribution of continuum models. The z > 6.5 quasars show the same emission properties as their counterparts at lower redshifts. The z > 6.5 quasars host BHs with masses of ∼10{sup 9} M{sub ☉} that are accreting close to the Eddington luminosity ((log(L{sub Bol}/L{sub Edd})) = –0.4 ± 0.2), in agreement with what has been observed for a sample of 4.0 < z < 6.5 quasars. By comparing the Si IV/C IV and C III]/C IV flux ratios with the results obtained from luminosity-matched samples at z ∼ 6 and 2 ≤ z ≤ 4.5, we find no evidence of evolution of the line ratios with cosmic time. We compare the measured Fe II/Mg II flux ratios with those obtained for a sample of 4.0 < z < 6.4 sources. The two samples are analyzed using a consistent procedure. There is no evidence that the Fe II/Mg II flux ratio evolves between z = 7 and z = 4. Under the assumption that the Fe II/Mg II traces the Fe/Mg abundance ratio, this implies the presence of major episodes of chemical enrichment in the quasar hosts in the first ∼0.8 Gyr after the Big Bang.

Stark broadening of the 1640- and 4686-A lines of ionized helium

International Nuclear Information System (INIS)

Greene, R.L.

1976-01-01

The Stark-broadened profiles of the 1640- and 4686-A lines of ionized helium have been calculated using an approximation to the electron broadening operator in the unified classical-path theory of Smith, Vidal, and Cooper. The approximation is such that the results reproduce the time-ordered impact-theory results in the line center, and the ionized-radiator quasistatic results in the far wings. Sample calculations at n/sub e/ = 10/sup 17/ cm/sup -3/ and T = 40 000 degreeK are found to give significantly more narrow profiles than the corresponding modified-impact-theory results because of a different treatment of the lower-state interaction. Indirect comparison with experiment indicates that the calculated lines are too narrow, but it is expected that the inclusion of neglected effects of ion dynamics and inelastic collisions would improve agreement

Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks

Energy Technology Data Exchange (ETDEWEB)

Nischkauer, Winfried [Institute of Chemical Technologies and Analytics, Vienna University of Technology, Vienna (Austria); Department of Analytical Chemistry, Ghent University, Ghent (Belgium); Vanhaecke, Frank [Department of Analytical Chemistry, Ghent University, Ghent (Belgium); Bernacchi, Sébastien; Herwig, Christoph [Institute of Chemical Engineering, Vienna University of Technology, Vienna (Austria); Limbeck, Andreas, E-mail: Andreas.Limbeck@tuwien.ac.at [Institute of Chemical Technologies and Analytics, Vienna University of Technology, Vienna (Austria)

2014-11-01

Nebulising liquid samples and using the aerosol thus obtained for further analysis is the standard method in many current analytical techniques, also with inductively coupled plasma (ICP)-based devices. With such a set-up, quantification via external calibration is usually straightforward for samples with aqueous or close-to-aqueous matrix composition. However, there is a variety of more complex samples. Such samples can be found in medical, biological, technological and industrial contexts and can range from body fluids, like blood or urine, to fuel additives or fermentation broths. Specialized nebulizer systems or careful digestion and dilution are required to tackle such demanding sample matrices. One alternative approach is to convert the liquid into a dried solid and to use laser ablation for sample introduction. Up to now, this approach required the application of internal standards or matrix-adjusted calibration due to matrix effects. In this contribution, we show a way to circumvent these matrix effects while using simple external calibration for quantification. The principle of representative sampling that we propose uses radial line-scans across the dried residue. This compensates for centro-symmetric inhomogeneities typically observed in dried spots. The effectiveness of the proposed sampling strategy is exemplified via the determination of phosphorus in biochemical fermentation media. However, the universal viability of the presented measurement protocol is postulated. Detection limits using laser ablation-ICP-optical emission spectrometry were in the order of 40 μg mL{sup −1} with a reproducibility of 10 % relative standard deviation (n = 4, concentration = 10 times the quantification limit). The reported sensitivity is fit-for-purpose in the biochemical context described here, but could be improved using ICP-mass spectrometry, if future analytical tasks would require it. Trueness of the proposed method was investigated by cross-validation with

Launched electrons in plasma opening switches

International Nuclear Information System (INIS)

Mendel, C.W. Jr.; Rochau, G.E.; Sweeney, M.A.; McDaniel, D.H.; Quintenz, J.P.; Savage, M.E.; Lindman, E.L.; Kindel, J.M.

1989-01-01

Plasma opening switches have provided a means to improve the characteristics of super-power pulse generators. Recent advances involving plasma control with fast and slow magnetic fields have made these switches more versatile, allowing for improved switch uniformity, triggering, and opening current levels that are set by the level of auxiliary fields. Such switches necessarily involve breaks in the translational symmetry of the transmission line geometry and therefore affect the electron flow characteristics of the line. These symmetry breaks are the result of high electric field regions caused by plasma conductors remaining in the transmission line, ion beams crossing the line, or auxilliary magnetic field regions. Symmetry breaks cause the canonical momentum of the electrons to change, thereby moving them away from the cathode. Additional electrons are pulled from the cathode into the magnetically insulated flow, resulting in an excess of electron flow over that expected for the voltage and line current downstream of the switch. We call these electrons ''launched electrons''. Unless they are recaptured at the cathode or else are fed into the load and used beneficially, they cause a large power loss downstream. This paper will show examples of SuperMite and PBFA II data showing these losses, explain the tools we are using to study them, and discuss the mechanisms we will employ to mitigate the problem. The losses will be reduced primarily by reducing the amount of launched electron flow. 7 refs., 9 figs

Martian Electron Temperatures in the Sub Solar Region.

Science.gov (United States)

Fowler, C. M.; Peterson, W. K.; Andersson, L.; Thiemann, E.; Mayyasi, M.; Yelle, R. V.; Benna, M.; Espley, J. R.

2017-12-01

Observations from Viking, and MAVEN have shown that the observed ionospheric electron temperatures are systematically higher than those predicted by many models. Because electron temperature is a balance between heating, cooling, and heat transport, we systematically compare the magnitude of electron heating from photoelectrons, electron cooling and heat transport, as a function of altitude within 30 degrees of the sub solar point. MAVEN observations of electron temperature and density, EUV irradiance, neutral and ion composition are used to evaluate terms in the heat equation following the framework of Matta et al. (Icarus, 2014, doi:10.1016/j.icarus.2013.09.006). Our analysis is restricted to inbound orbits where the magnetic field is within 30 degrees of horizontal. MAVEN sampled the sub solar region in May 2015 and again in May 2017, in near northern spring equinoctial conditions. Solar activity was higher and the spacecraft sampled altitudes down to 120 km in 2015, compared to 160 km in 2017. We find that between 160 and 200 km the Maven electron temperatures are in thermal equilibrium, in the sub solar region, on field lines inclined less than 30 degrees to the horizontal. Above 200km the data suggest that heating from other sources, such as wave heating are significant. Below 160 km some of the discrepancy comes from measurement limitations. This is because the MAVEN instrument cannot resolve the lowest electron temperatures, and because some cooling rates scale as the difference between the electron and neutral temperatures.

Incoherent Scatter Radar Studies of Daytime Plasma Lines

Science.gov (United States)

Djuth, Frank T.; Carlson, Herbert C.; Zhang, Liwei D.

2018-03-01

First results from wideband (electron phase energies of 5-51 eV), high-resolution (0.1 eV) spectral measurements of photoelectron-enhanced plasma lines made with the 430 MHz radar at Arecibo Observatory are presented. In the F region, photoelectrons produced by solar EUV line emissions (He II and Mg IX) give rise to plasma line spectral peaks/valleys. These and other structures occur within an enhancement zone extending from electron phase energies of 14-27 eV in both the bottomside and topside ionosphere. However, photoelectron-thermal electron Coulomb energy losses can lead to a broadened spectral structure with no resolved peaks in the topside ionosphere. The plasma line energy spectra obtained in the enhancement zone exhibit a unique relation in that phase energy is dependent on pitch angle; this relation does not exist in any other part of the energy spectrum. Moreover, large fluctuations in the difference frequency between the upshifted and downshifted plasma lines are evident in the 14-27 eV energy interval. At high phase energies near 51 eV the absolute intensities of photoelectron-excited Langmuir waves are much larger than those predicted by existing theory. The new measurements call for a revision/improvement of plasma line theory in several key areas.

Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks.

Science.gov (United States)

Nischkauer, Winfried; Vanhaecke, Frank; Bernacchi, Sébastien; Herwig, Christoph; Limbeck, Andreas

2014-11-01

Nebulising liquid samples and using the aerosol thus obtained for further analysis is the standard method in many current analytical techniques, also with inductively coupled plasma (ICP)-based devices. With such a set-up, quantification via external calibration is usually straightforward for samples with aqueous or close-to-aqueous matrix composition. However, there is a variety of more complex samples. Such samples can be found in medical, biological, technological and industrial contexts and can range from body fluids, like blood or urine, to fuel additives or fermentation broths. Specialized nebulizer systems or careful digestion and dilution are required to tackle such demanding sample matrices. One alternative approach is to convert the liquid into a dried solid and to use laser ablation for sample introduction. Up to now, this approach required the application of internal standards or matrix-adjusted calibration due to matrix effects. In this contribution, we show a way to circumvent these matrix effects while using simple external calibration for quantification. The principle of representative sampling that we propose uses radial line-scans across the dried residue. This compensates for centro-symmetric inhomogeneities typically observed in dried spots. The effectiveness of the proposed sampling strategy is exemplified via the determination of phosphorus in biochemical fermentation media. However, the universal viability of the presented measurement protocol is postulated. Detection limits using laser ablation-ICP-optical emission spectrometry were in the order of 40 μg mL - 1 with a reproducibility of 10 % relative standard deviation (n = 4, concentration = 10 times the quantification limit). The reported sensitivity is fit-for-purpose in the biochemical context described here, but could be improved using ICP-mass spectrometry, if future analytical tasks would require it. Trueness of the proposed method was investigated by cross-validation with

Radial line-scans as representative sampling strategy in dried-droplet laser ablation of liquid samples deposited on pre-cut filter paper disks

Science.gov (United States)

Nischkauer, Winfried; Vanhaecke, Frank; Bernacchi, Sébastien; Herwig, Christoph; Limbeck, Andreas

2014-11-01

Nebulising liquid samples and using the aerosol thus obtained for further analysis is the standard method in many current analytical techniques, also with inductively coupled plasma (ICP)-based devices. With such a set-up, quantification via external calibration is usually straightforward for samples with aqueous or close-to-aqueous matrix composition. However, there is a variety of more complex samples. Such samples can be found in medical, biological, technological and industrial contexts and can range from body fluids, like blood or urine, to fuel additives or fermentation broths. Specialized nebulizer systems or careful digestion and dilution are required to tackle such demanding sample matrices. One alternative approach is to convert the liquid into a dried solid and to use laser ablation for sample introduction. Up to now, this approach required the application of internal standards or matrix-adjusted calibration due to matrix effects. In this contribution, we show a way to circumvent these matrix effects while using simple external calibration for quantification. The principle of representative sampling that we propose uses radial line-scans across the dried residue. This compensates for centro-symmetric inhomogeneities typically observed in dried spots. The effectiveness of the proposed sampling strategy is exemplified via the determination of phosphorus in biochemical fermentation media. However, the universal viability of the presented measurement protocol is postulated. Detection limits using laser ablation-ICP-optical emission spectrometry were in the order of 40 μg mL- 1 with a reproducibility of 10 % relative standard deviation (n = 4, concentration = 10 times the quantification limit). The reported sensitivity is fit-for-purpose in the biochemical context described here, but could be improved using ICP-mass spectrometry, if future analytical tasks would require it. Trueness of the proposed method was investigated by cross-validation with

Deriving the coronal hole electron temperature: electron density dependent ionization / recombination considerations

International Nuclear Information System (INIS)

Doyle, John Gerard; Perez-Suarez, David; Singh, Avninda; Chapman, Steven; Bryans, Paul; Summers, Hugh; Savin, Daniel Wolf

2010-01-01

Comparison of appropriate theoretically derived line ratios with observational data can yield estimates of a plasma's physical parameters, such as electron density or temperature. The usual practice in the calculation of the line ratio is the assumption of excitation by electrons/protons followed by radiative decay. Furthermore, it is normal to use the so-called coronal approximation, i.e. one only considers ionization and recombination to and from the ground-state. A more accurate treatment is to include ionization/recombination to and from metastable levels. Here, we apply this to two lines from adjacent ionization stages, Mg IX 368 A and Mg X 625 A, which has been shown to be a very useful temperature diagnostic. At densities typical of coronal hole conditions, the difference between the electron temperature derived assuming the zero density limit compared with the electron density dependent ionization/recombination is small. This, however, is not the case for flares where the electron density is orders of magnitude larger. The derived temperature for the coronal hole at solar maximum is around 1.04 MK compared to just below 0.82 MK at solar minimum.

Contribution of vitamin K1 to the electron spin polarization in spinach photosystem I

International Nuclear Information System (INIS)

Rustandi, R.R.; Snyder, S.W.; Feezel, L.L.; Michalski, T.J.; Norris, J.R.; Thurnauer, M.C.; Biggins, J.

1990-01-01

The electron spin polarized (ESP) electron paramagnetic resonance (EPR) signal observed in spinach photosystem I (PSI) particles was examined in preparations depleted of vitamin K1 by solvent extraction and following biological reconstitution by the quinone. The ESP EPR signal was not detected in the solvent-extracted PSI sample but was restored upon reconstitution with either protonated or deuterated vitamin K1 under conditions that also restored electron transfer to the terminal PSI acceptors. Reconstitution using deuterated vitamin K1 resulted in a line narrowing of the ESP EPR signal, supporting the conclusion that the ESP EPR signals in the reconstituted samples arise from a radical pair consisting of the oxidized PSI primary donor, P700+, and reduced vitamin K1

Impact of ambient environment on the electronic structure of CuPc/Au sample

Science.gov (United States)

Sinha, Sumona; Mukherjee, M.

2018-02-01

The performances of organic devices are crucially connected with their stability in the ambient environment. The impact of 24 h. Ambient environment exposure to the electronic structures of about 12 nm thick CuPc thin film on clean Au substrate have been studied employing UV photoemission spectroscopy technique. X-ray photoemission spectroscopy (XPS) was used to find out the origin of the change of the electronic structures in the sample with the exposure. The XPS study suggests that the oxidation occurs at the CuPc thin film. Due to the adsorption of oxygen in the CuPc film from the ambient air, charge carriers are formed within the CuPc film. Moreover, the XPS results imply that the CuPc film is sufficiently thinner for diffusing oxygen molecules through it and gets physically absorbed on Au substrate during the ambient exposure. Consequently, the hole injection barrier height of pristine CuPc film, grown on Au substrate, is reduced by about 0.50 eV and work-function of the pristine CuPc sample is enhanced by around 0.25 eV in the exposure. The findings will help to understand the mechanism that governs the degradation of performance of CuPc based devices in ambient environment.

BROAD ABSORPTION LINE DISAPPEARANCE ON MULTI-YEAR TIMESCALES IN A LARGE QUASAR SAMPLE

Energy Technology Data Exchange (ETDEWEB)

Filiz Ak, N.; Brandt, W. N.; Schneider, D. P. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Hall, P. B. [Department of Physics and Astronomy, York University, 4700 Keele St., Toronto, Ontario M3J 1P3 (Canada); Anderson, S. F.; Gibson, R. R. [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Lundgren, B. F. [Department of Physics, Yale University, New Haven, CT 06511 (United States); Myers, A. D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Petitjean, P. [Institut d' Astrophysique de Paris, Universite Paris 6, F-75014, Paris (France); Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 92420 (United States); Shen Yue [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States); York, D. G. [Department of Astronomy and Astrophysics, and Enrico Fermi Institute, University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637 (United States); Bizyaev, D.; Brinkmann, J.; Malanushenko, E.; Oravetz, D. J.; Pan, K.; Simmons, A. E. [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Weaver, B. A., E-mail: nfilizak@astro.psu.edu [Center for Cosmology and Particle Physics, New York University, New York, NY 10003 (United States)

2012-10-01

We present 21 examples of C IV broad absorption line (BAL) trough disappearance in 19 quasars selected from systematic multi-epoch observations of 582 bright BAL quasars (1.9 < z < 4.5) by the Sloan Digital Sky Survey-I/II (SDSS-I/II) and SDSS-III. The observations span 1.1-3.9 yr rest-frame timescales, longer than have been sampled in many previous BAL variability studies. On these timescales, Almost-Equal-To 2.3% of C IV BAL troughs disappear and Almost-Equal-To 3.3% of BAL quasars show a disappearing trough. These observed frequencies suggest that many C IV BAL absorbers spend on average at most a century along our line of sight to their quasar. Ten of the 19 BAL quasars showing C IV BAL disappearance have apparently transformed from BAL to non-BAL quasars; these are the first reported examples of such transformations. The BAL troughs that disappear tend to be those with small-to-moderate equivalent widths, relatively shallow depths, and high outflow velocities. Other non-disappearing C IV BALs in those nine objects having multiple troughs tend to weaken when one of them disappears, indicating a connection between the disappearing and non-disappearing troughs, even for velocity separations as large as 10,000-15,000 km s{sup -1}. We discuss possible origins of this connection including disk-wind rotation and changes in shielding gas.

On-line Observation Of Electron Beam Bunches In The Large Storage Ring Of Kurchatov Srs

CERN Document Server

Ioudin, L I; Krylov, Y V; Rezvov, V A; Stirin, A I; Valentinov, A G; Yupinov, Y L

2004-01-01

A complex of instrumentation for visual quantitative estimation of electron beam bunches in the big storage ring of Kurchatov Synchrotron Radiation Centre (KSRC) is tested. The bunches pass through a cylindrical electrostatic sensor whose signal is recorded by a wide-band oscillograph. The TV camera reads the optical image of the signal from the oscillograph screen. The TV signal numbering board inputs the video image to the computer memory. The monitor displays the beam bunch structure. A special program provides on-line visualisation of bunch behaviour on the beam orbit. The images of beam structure and a series of images showing the beam behaviour in the regimes of accumulation, acceleration and in the stationary regime a full power are numbered and stored.

Preparation and applicability of fresh fruit samples for the identification of radiation treatment by EPR

Energy Technology Data Exchange (ETDEWEB)

Yordanov, Nicola D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)], E-mail: ndyepr@bas.bg; Aleksieva, Katerina [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

2009-03-15

The results of electron paramagnetic resonance (EPR) study on fresh fruits (whole pulp of pears, apples, peaches, apricots, avocado, kiwi and mango) before and after gamma-irradiation are reported using two drying procedures before EPR investigation. In order to remove water from non-irradiated and irradiated samples of the first batch, the pulp of fresh fruits is pressed, and the solid residue is washed with alcohol and dried at room temperature. The fruits of the second batch are pressed and dried in a standard laboratory oven at 40 deg. C. The results obtained with both drying procedures are compared. All samples under study show a singlet EPR line with g=2.0048{+-}0.0005 before irradiation. Irradiation gives rise to typical 'cellulose-like' EPR spectrum featuring one intensive line with g=2.0048{+-}0.0005 and two very weak satellite lines situated 3 mT at left and right of the central line. Only mango samples show a singlet line after irradiation. The fading kinetics of radiation-induced EPR signal is studied for a period of 50 days after irradiation. When the irradiated fruit samples are stored in their natural state and dried just before each EPR measurement, the satellite lines are measurable for less than 17 days of storage. Irradiated fruit samples, when stored dried, lose for 50 days ca. 40% of their radiation-induced radicals if treated with alcohol or ca. 70% if dried in an oven. The reported results unambiguously show that the presence of the satellite lines in the EPR spectra could be used for identification of radiation processing of fresh fruits, thus extending the validity of European Protocol EN 1787 (2000). Foodstuffs-Detection of Irradiated Food Containing Cellulose by EPR Spectroscopy. European Committee for Standardisation. Brussels for dry herbs.

Preparation and applicability of fresh fruit samples for the identification of radiation treatment by EPR

International Nuclear Information System (INIS)

Yordanov, Nicola D.; Aleksieva, Katerina

2009-01-01

The results of electron paramagnetic resonance (EPR) study on fresh fruits (whole pulp of pears, apples, peaches, apricots, avocado, kiwi and mango) before and after gamma-irradiation are reported using two drying procedures before EPR investigation. In order to remove water from non-irradiated and irradiated samples of the first batch, the pulp of fresh fruits is pressed, and the solid residue is washed with alcohol and dried at room temperature. The fruits of the second batch are pressed and dried in a standard laboratory oven at 40 deg. C. The results obtained with both drying procedures are compared. All samples under study show a singlet EPR line with g=2.0048±0.0005 before irradiation. Irradiation gives rise to typical 'cellulose-like' EPR spectrum featuring one intensive line with g=2.0048±0.0005 and two very weak satellite lines situated 3 mT at left and right of the central line. Only mango samples show a singlet line after irradiation. The fading kinetics of radiation-induced EPR signal is studied for a period of 50 days after irradiation. When the irradiated fruit samples are stored in their natural state and dried just before each EPR measurement, the satellite lines are measurable for less than 17 days of storage. Irradiated fruit samples, when stored dried, lose for 50 days ca. 40% of their radiation-induced radicals if treated with alcohol or ca. 70% if dried in an oven. The reported results unambiguously show that the presence of the satellite lines in the EPR spectra could be used for identification of radiation processing of fresh fruits, thus extending the validity of European Protocol EN 1787 (2000). Foodstuffs-Detection of Irradiated Food Containing Cellulose by EPR Spectroscopy. European Committee for Standardisation. Brussels for dry herbs

Preparation and applicability of fresh fruit samples for the identification of radiation treatment by EPR

Science.gov (United States)

Yordanov, Nicola D.; Aleksieva, Katerina

2009-03-01

The results of electron paramagnetic resonance (EPR) study on fresh fruits (whole pulp of pears, apples, peaches, apricots, avocado, kiwi and mango) before and after gamma-irradiation are reported using two drying procedures before EPR investigation. In order to remove water from non-irradiated and irradiated samples of the first batch, the pulp of fresh fruits is pressed, and the solid residue is washed with alcohol and dried at room temperature. The fruits of the second batch are pressed and dried in a standard laboratory oven at 40 °C. The results obtained with both drying procedures are compared. All samples under study show a singlet EPR line with g=2.0048±0.0005 before irradiation. Irradiation gives rise to typical "cellulose-like" EPR spectrum featuring one intensive line with g=2.0048±0.0005 and two very weak satellite lines situated 3 mT at left and right of the central line. Only mango samples show a singlet line after irradiation. The fading kinetics of radiation-induced EPR signal is studied for a period of 50 days after irradiation. When the irradiated fruit samples are stored in their natural state and dried just before each EPR measurement, the satellite lines are measurable for less than 17 days of storage. Irradiated fruit samples, when stored dried, lose for 50 days ca. 40% of their radiation-induced radicals if treated with alcohol or ca. 70% if dried in an oven. The reported results unambiguously show that the presence of the satellite lines in the EPR spectra could be used for identification of radiation processing of fresh fruits, thus extending the validity of European Protocol EN 1787 (2000). Foodstuffs—Detection of Irradiated Food Containing Cellulose by EPR Spectroscopy. European Committee for Standardisation. Brussels for dry herbs.

Iron forbidden lines in tokamak discharges

International Nuclear Information System (INIS)

Suckewer, S.; Hinnov, E.

1979-03-01

Several spectrum lines from forbidden transitions in the ground configurations of highly ionized atoms have been observed in the PLT tokamak discharges. Such lines allow localized observations, in the high-temperature regions of the plasma, of ion-temperatures, plasma motions, and spatial distributions of ions. Measured absolute intensities of the forbidden lines have been compared with simultaneous observations of the ion resonance lines and with model calculations in order to deduce the mechanism of level populaions by means of electron collisions and radiative transitions

Iron forbidden lines in tokamak discharges

Energy Technology Data Exchange (ETDEWEB)

Suckewer, S.; Hinnov, E.

1979-03-01

Several spectrum lines from forbidden transitions in the ground configurations of highly ionized atoms have been observed in the PLT tokamak discharges. Such lines allow localized observations, in the high-temperature regions of the plasma, of ion-temperatures, plasma motions, and spatial distributions of ions. Measured absolute intensities of the forbidden lines have been compared with simultaneous observations of the ion resonance lines and with model calculations in order to deduce the mechanism of level populaions by means of electron collisions and radiative transitions.

Line Emission and X-ray Line Polarization of Multiply Ionized Mo Ions

Science.gov (United States)

Petkov, E. E.; Safronova, A. S.; Kantsyrev, V. L.; Shlyaptseva, V. V.; Stafford, A.; Safronova, U. I.; Shrestha, I. K.; Schultz, K. A.; Childers, R.; Cooper, M. C.; Beiersdorfer, P.; Hell, N.; Brown, G. V.

2016-10-01

We present a comprehensive experimental and theoretical study of the line emission from multiply ionized Mo ions produced by two different sets of experiments: at LLNL EBIT and the pulsed power generator Zebra at UNR. Mo line emission and polarization measurements were accomplished at EBIT for the first time. In particular, benchmarking experiments at the LLNL EBIT with Mo ions produced at electron beam energies from 2.75 keV up to 15 keV allowed us to break down these very complicated spectra into spectra with only few ionization stages and to select processes that influence them as well as to measure line polarization. The EBIT data were recorded using the EBIT Calorimeter Spectrometer and a crystal spectrometer with a Ge crystal. X-ray Mo spectra and pinhole images were collected from Z-pinch plasmas produced from various wire loads. Non-LTE modeling, high-precision relativistic atomic and polarization data were used to analyze L-shell Mo spectra. The influence of different plasma processes including electron beams on Mo line radiation is summarized. This work was supported by NNSA under DOE Grant DE-NA0002954. Experiments at the NTF/UNR were funded in part by DE-NA0002075. Work at LLNL was performed under the auspices of the U.S. DOE under contract DE-AC52-07NA27344.

Electron beam effects in auger electron spectroscopy and scanning electron microscopy

International Nuclear Information System (INIS)

Fontaine, J.M.; Duraud, J.P.; Le Gressus, C.

1979-01-01

Electron beam effects on Si(100) and 5% Fe/Cr alloy samples have been studied by measurements of the secondary electron yield delta, determination of the surface composition by Auger electron spectroscopy and imaging with scanning electron microscopy. Variations of delta as a function of the accelerating voltage Esub(p) (0.5 -9 Torr has no effect on technological samples covered with their reaction layers; the sensitivities to the beam depend rather on the earlier mechanical, thermal and chemical treatment of the surfaces. (author)

Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies

Energy Technology Data Exchange (ETDEWEB)

Rakshit, Suvendu; Stalin, C. S., E-mail: suvenduat@gmail.com [Indian Institute of Astrophysics, Block II, Koramangala, Bangalore-560034 (India)

2017-06-20

We studied the optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z < 0.8 to investigate any differences in their OV properties. Using archival optical V -band light curves from the Catalina Real Time Transient Survey that span 5–9 years and modeling them using damped random walk, we estimated the amplitude of variability. We found that NLSy1 galaxies as a class show lower amplitude of variability than their broad-line counterparts. In the sample of both NLSy1 and BLSy1 galaxies, radio-loud sources are found to have higher variability amplitude than radio-quiet sources. Considering only sources that are detected in the X-ray band, NLSy1 galaxies are less optically variable than BLSy1 galaxies. The amplitude of variability in the sample of both NLSy1 and BLSy1 galaxies is found to be anti-correlated with Fe ii strength but correlated with the width of the H β line. The well-known anti-correlation of variability–luminosity and the variability–Eddington ratio is present in our data. Among the radio-loud sample, variability amplitude is found to be correlated with radio-loudness and radio-power, suggesting that jets also play an important role in the OV in radio-loud objects, in addition to the Eddington ratio, which is the main driving factor of OV in radio-quiet sources.

Effect of the sample annealing temperature and sample crystallographic orientation on the charge kinetics of MgO single crystals subjected to keV electron irradiation.

Science.gov (United States)

Boughariou, A; Damamme, G; Kallel, A

2015-04-01

This paper focuses on the effect of sample annealing temperature and crystallographic orientation on the secondary electron yield of MgO during charging by a defocused electron beam irradiation. The experimental results show that there are two regimes during the charging process that are better identified by plotting the logarithm of the secondary electron emission yield, lnσ, as function of the total trapped charge in the material QT. The impact of the annealing temperature and crystallographic orientation on the evolution of lnσ is presented here. The slope of the asymptotic regime of the curve lnσ as function of QT, expressed in cm(2) per trapped charge, is probably linked to the elementary cross section of electron-hole recombination, σhole, which controls the trapping evolution in the reach of the stationary flow regime. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

Determining the static electronic and vibrational energy correlations via two-dimensional electronic-vibrational spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Dong, Hui; Lewis, Nicholas H. C.; Oliver, Thomas A. A.; Fleming, Graham R., E-mail: grfleming@lbl.gov [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, Californial 94720 (United States); Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720 (United States)

2015-05-07

Changes in the electronic structure of pigments in protein environments and of polar molecules in solution inevitably induce a re-adaption of molecular nuclear structure. Both changes of electronic and vibrational energies can be probed with visible or infrared lasers, such as two-dimensional electronic spectroscopy or vibrational spectroscopy. The extent to which the two changes are correlated remains elusive. The recent demonstration of two-dimensional electronic-vibrational (2DEV) spectroscopy potentially enables a direct measurement of this correlation experimentally. However, it has hitherto been unclear how to characterize the correlation from the spectra. In this paper, we present a theoretical formalism to demonstrate the slope of the nodal line between the excited state absorption and ground state bleach peaks in the spectra as a characterization of the correlation between electronic and vibrational transition energies. We also show the dynamics of the nodal line slope is correlated to the vibrational spectral dynamics. Additionally, we demonstrate the fundamental 2DEV spectral line-shape of a monomer with newly developed response functions.

Calculation of the line shapes of radiators immersed in plasma

International Nuclear Information System (INIS)

Hayrapetian, A.S.

1987-01-01

This work reports the results of theoretical calculations of line shapes of radiators immersed in plasma. The fluctuating electric field of the plasma perturbs the atomic structure of the immersed ions or atoms. The perturbed line shape is an important diagnostic tool for the temperature and density measurements of plasma. The line-shape calculation here is done by first deriving the line-shape expression, then it is shown that the problem is equivalent to calculating the temperature Green's function of the bound electron. The total Hamiltonian of the system includes the atomic, plasma, and atom-plasma parts. The temperature Green's function is calculated perturbatively by expanding in orders of atom-plasma interaction. By solving a Dyson equation, the dressed Green's functions of the bound electrons are obtained. At this point, the line shape is calculated by an analytic continuation from the complex frequency plane to real line. To derive the atomic electron Green's function, the momentum integral in the self-energy is approximated by a Riemann sum. With this approximation, the algebraic form of the line shape is obtained for an undetermined number of terms in the Riemann sum. Numerical calculation of line shape is done by using this result

Radio recombination lines from H II regions

International Nuclear Information System (INIS)

Silverglate, P.R.

1978-01-01

Radio recombination lines have been observed from forty-six H II regions. The Arecibo 1000-foot radio telescope was used to provide high sensitivity and high angular resolution at 1400 MHz (gain approx. 7.7 0 K/Jy, HPBW = 3:2) and 2372 MHZ (gain approx. 6.3 0 K/Jy, HPBW = 2'). Observations were made at 1400 MHz in the frequency switching mode, and at 2372 MHz in the total power mode. Gaussians were fit to be observed lines to derive velocities, line widths, and line temperatures. From the velocities kinematic distances were derived. For eleven sources H I absorption measurements were also made. The absorption spectra enabled the kinematic distance ambiguity to be resolved for some sources. The absorption spectra themselves were found to have extremely sharp, non-gaussian edges. One explanation for these is a model where the interstellar medium contains many H I cloudlets with T/sub s/less than or equal to 100 0 K and turbulent velocities less than or equal to 3 km/s. The H I absorption spectrum is then a superposition of many narrow gaussian profiles. It was also found from a comparison of H I absorption velocities with radio recombination line velocities that peculiar motions exist in the interstellar medium with velocities of up to 10 km/s. Using the measured line temperatures and continuum temperatures, estimates were desired of emission measures, electron temperatures, and electron densities, using a non-LTE analysis. Non-LTE effects were important only for the hottest and densest H II regions. The non-LTE calculations were checked through a comparison derivation of electron temperatures using hydrogen beta lines

On-line transmission electron microscopic image analysis of chromatin texture for differentiation of thyroid gland tumors.

Science.gov (United States)

Kriete, A; Schäffer, R; Harms, H; Aus, H M

1987-06-01

Nuclei of the cells from the thyroid gland were analyzed in a transmission electron microscope by direct TV scanning and on-line image processing. The method uses the advantages of a visual-perception model to detect structures in noisy and low-contrast images. The features analyzed include area, a form factor and texture parameters from the second derivative stage. Three tumor-free thyroid tissues, three follicular adenomas, three follicular carcinomas and three papillary carcinomas were studied. The computer-aided cytophotometric method showed that the most significant differences were the statistics of the chromatin texture features of homogeneity and regularity. These findings document the possibility of an automated differentiation of tumors at the ultrastructural level.

In-situ transmission electron microscopy of the solid-phase epitaxial growth of GaAs: sample preparation and artifact characterization

International Nuclear Information System (INIS)

Llewellyn, D.J.; Llewellyn, D.J.; Belay, K.B.; Ridgway, M.C.

1998-01-01

In-situ transmission electron microscopy (TEM) has been used to characterize the solid phase epitaxial growth of amorphized GaAs at a temperature of 260 deg C. To maximize heat transfer from the heated holder to the sample and minimize electron-irradiation induced artifacts, non-conventional methodologies were utilized for the preparation of cross-sectional samples. GaAs 3x1 mm rectangular wafers were cleaved then glued face-to-face to form a wafer stack size of 3x3 mm while maintaining the TEM region at the center. This stack was subsequently polished on the cross-section to a thickness of ∼ 200 μm. A 3 mm disc was then cut perpendicular to the cross-section using a Gatan ultrasonic cutter. The disc was polished then dimpled on both sides to a thickness of ∼ 15 μm. This was ion-beam milled at liquid nitrogen temperature to an electron-transparent layer. From a comparison of in-situ and ex-situ measurements of the recrystallization rate, the actual sample temperature during in-situ characterization was estimated to deviate by ≤ 20 deg C from that of the heated holder. The influence of electron-irradiation was found to be negligible by comparing the recrystallization rate and microstructure of irradiated and unirradiated regions of comparable thickness. Similarly, the influence of the 'thin-foil effect' was found to be negligible by comparing the recrystallization rate and microstructure of thick and thin regions, the former determined after the removal of the sample from the microscope and further ion-beam milling of tens of microns of material. In conclusion, the potential influence of artifacts during in-situ TEM can be minimized by the appropriate choice of sample preparation procedures. (authors)

Solid-phase extraction of polar pesticides from environmental water samples on graphitized carbon and Empore-activated carbon disks and on-line coupling to octadecyl-bonded silica analytical columns.

NARCIS (Netherlands)

Slobodník, J.; Oztekizan, O.; Lingeman, H.; Brinkman, U.A.T.

1996-01-01

The suitability of Empore-activated carbon disks (EACD), Envi-Carb graphitized carbon black (GCB) and CPP-50 graphitized carbon for the trace enrichment of polar pesticides from water samples was studied by means of off-line and on-line solid-phase extraction (SPE). In the off-line procedure, 0.5-2

Detector line spread functions determined analytically by transport of Compton recoil electrons

International Nuclear Information System (INIS)

Veld, A.A. van't; Luijk, P. van; Praamstra, F.; Hulst, P.C. van der

2001-01-01

To achieve the maximum benefit of conformal radiation therapy it is necessary to obtain accurate knowledge of radiation beam penumbras based on high-resolution relative dosimetry of beam profiles. For this purpose there is a need to perform high-resolution dosimetry with well-established routine dosimeters, such as ionization chambers or diodes. Profiles measured with these detectors must be corrected for the dosimeter's nonideal response, caused by finite dimensions and, in the case of an ionization chamber, the alteration of electron transport and a contribution of electrons recoiled in the chamber wall and the central electrode. For this purpose the line spread function (LSF) of the detector is needed. The experimental determination of LSFs is cumbersome and restricted to the specific detector and beam energy spectrum used. Therefore, a previously reported analytical model [Med. Phys. 27, 923-934 (2000)] has been extended to determine response profiles of routine dosimeters: shielded diodes and, in particular, ionization chambers, in primary dose slit beams. The model combines Compton scattering of incident photons, the transport of recoiled electrons by Fermi-Eyges small-angle multiple scattering theory, and functions to limit electron transport. It yields the traveling direction and the energy of electrons upon incidence on the detector surface. In the case of ionization chambers, geometrical considerations are then sufficient to calculate the relative amount of ionization in chamber air, i.e., the detector response, as a function of the detector location in the slit beam. In combination with the previously reported slit beam dose profiles, the LSF can then readily be derived by reconstruction techniques. Since the spectral contributions are preserved, the LSF of a dosimeter is defined for any beam for which the effective spectrum is known. The detector response profiles calculated in this study have been verified in a telescopic slit beam geometry, and were

Application of Numerical Analysis of the Shape of Electron Paramagnetic Resonance Spectra for Determination of the Number of Different Groups of Radicals in the Burn Wounds

Directory of Open Access Journals (Sweden)

Paweł Olczyk

2017-01-01

Full Text Available Background. The evidence exists that radicals are crucial agents necessary for the wound regeneration helping to enhance the repair process. Materials and methods. The lineshape of the electron paramagnetic resonance (EPR spectra of the burn wounds measured with the low microwave power (2.2 mW was numerically analyzed. The experimental spectra were fitted by the sum of two and three lines. Results. The number of the lines in the EPR spectrum corresponded to the number of different groups of radicals in the natural samples after thermal treatment. The component lines were described by Gaussian and Lorentzian functions. The spectra of the burn wounds were superposition of three lines different in shape and in linewidths. The best fitting was obtained for the sum of broad Gaussian, broad Lorentzian, and narrow Lorentzian lines. Dipolar interactions between the unpaired electrons widened the broad Gaussian and broad Lorentzian lines. Radicals with the narrow Lorentzian lines existed mainly in the tested samples. Conclusions. The spectral shape analysis may be proposed as a useful method for determining the number of different groups of radicals in the burn wounds.

Theoretical predictions for the polarization of the J = 0 - 1 neonlike germanium X-ray laser line in the presence of a directed beam of hot electrons

International Nuclear Information System (INIS)

Inal, M.K.; Dubau, J.; Cornille, M.

1998-01-01

The polarization of the neonlike germanium J = 0 - 1 laser line, which would arise from the existence of a directed beam of hot electrons in the amplifying plasma, is theoretically investigated. The relative populations of the magnetic sublevels in the lower J = 1 laser level have been determined by allowing for the processes of direct excitation from the 2p 6 ground level and collisional de-excitation from the upper J = 0 laser level. Elastic collisions leading to transitions between the M J = 0 and M J =1 sublevels within the lower level of the lasing line have also been taken into account. The required elastic and inelastic collision strengths for transitions between magnetic sublevels have been computed in a semi-relativistic distorted-wave approximation, for incident electron energies up to 15 keV. Our calculations predict a rather low degree of polarization for the J = 0 - 1 line, although the elastic collisions are found to play a negligibly small role in the redistribution of magnetic sublevel populations. (author)

Theoretical profiles of the spectral lines of the hydrogen atom

International Nuclear Information System (INIS)

Nguyen, H.; Herman, L.; Drawin, H.W.

1965-01-01

The line-broadening problem of the hydrogen lines has been formulated in the quasistatic approximation as far as the ions are concerned, and in the classical path approximation as far as the broadening due to collisions with electrons is concerned. These electrons interfere in different numerical results only by the self-correlation function of the fluctuating electrical field strength created at each point in the plasma. The Lewis correction has been applied, but using the whole velocity distribution function of the electrons. The formula which represents the usual impact profile, valid only for frequencies much smaller than the plasma frequency, has been extended using another formula which will be valid up to the neighbourhood of that spectral region where the quasi-static approximation begins to be valid also for the electrons. As an example, the line profile of Ly α is given by some graphs for T = 10 4 deg. K and electron densities N = 10 17 cm -3 and N = 10 18 cm -3 . (authors) [fr

Electronic Structure, Irreversibility Line and Magnetoresistance of Cu_0_._3Bi_2Se_3 Superconductor

International Nuclear Information System (INIS)

Yi He-Mian; Chen Chao-Yu; Sun Xuan; Xie Zhuo-Jin; Feng Ya; Liang Ai-Ji; Peng Ying-Ying; He Shao-Long; Zhao Lin; Liu Guo-Dong; Dong Xiao-Li; Zhang Jun; Zhou Xing-Jiang; Chen Chuang-Tian; Xu Zu-Yan; Gu Gen-Da

2015-01-01

Cu_xBi_2Se_3 is a superconductor that is a potential candidate for topological superconductors. We report our laser-based angle-resolved photoemission measurement on the electronic structure of the Cu_xBi_2Se_3 superconductor, and a detailed magneto-resistance measurement in both normal and superconducting states. We find that the topological surface state of the pristine Bi_2Se_3 topological insulator remains robust after the Cu-intercalation, while the Dirac cone location moves downward due to electron doping. Detailed measurements on the magnetic field-dependence of the resistance in the superconducting state establishes an irreversibility line and gives a value of the upper critical field at zero temperature of ∼4000 Oe for the Cu_0_._3Bi_2Se_3 superconductor with a middle point T_c of 1.9K. The relation between the upper critical field H_c_2 and temperature T is different from the usual scaling relation found in cuprates and in other kinds of superconductors. Small positive magneto-resistance is observed in Cu_0_._3Bi_2Se_3 superconductors up to room temperature. These observations provide useful information for further study of this possible candidate for topological superconductors. (paper)

Electron-phonon coupling in solubilized LHC II complexes of green plants investigated by line-narrowing and temperature-dependent fluorescence spectroscopy

CERN Document Server

Pieper, J K; Renger, G; Schödel, R; Voigt, J

2001-01-01

Line-narrowed and temperature-dependent fluorescence spectra are reported for the solubilized trimeric light-harvesting complex of Photosystem II (LHC II). Special attention has been paid to eliminate effects owing to reabsorption and to ensure that the line-narrowed fluorescence spectra are virtually unaffected by hole burning or scattering artifacts. Analysis of line-narrowed fluorescence spectra at 4.2 K indicates that the lowest Q//y-state of LHC II is characterized by weak electron-phonon coupling with a Huang-Rhys factor of similar to 0.9 and a broad and strongly asymmetric one- phonon profile with a peak frequency omega//m of 15 cm**-**1 and a width of Gamma = 105 cm**-**1. The 4.2 K fluorescence data are further consistent with the assignment of the lowest Q//y-state at similar to 680.0 nm and an inhomogeneous width of similar to 80 cm**- **1 gathered from a recent hole-burning study (Pieper et al. J. Phys. Chem. A 1999, 103, 2412). The temperature dependence of the fluorescence spectra of LHC II is s...

Time-resolving electron temperature diagnostic for ALCATOR C

International Nuclear Information System (INIS)

Fairfax, S.A.

1984-05-01

A diagnostic that provides time-resolved central electron temperatures has been designed, built, and tested on the ALCATOR C Tokamak. The diagnostic uses an array of fixed-wavelength x-ray crystal monochromators to sample the x-ray continuum and determine the absolute electron temperature. The resolution and central energy of each channel were chosen to exclude any contributions from impurity line radiation. This document describes the need for such a diagnostic, the design methodology, and the results with typical ALCATOR C plasmas. Sawtooth (m = 1) temperature oscillations were observed after pellet fueling of the plasma. This is the first time that such oscillations have been observed with an x-ray temperature diagnostic

Localization of fluorescently labeled structures in frozen-hydrated samples using integrated light electron microscopy.

Science.gov (United States)

Faas, F G A; Bárcena, M; Agronskaia, A V; Gerritsen, H C; Moscicka, K B; Diebolder, C A; van Driel, L F; Limpens, R W A L; Bos, E; Ravelli, R B G; Koning, R I; Koster, A J

2013-03-01

Correlative light and electron microscopy is an increasingly popular technique to study complex biological systems at various levels of resolution. Fluorescence microscopy can be employed to scan large areas to localize regions of interest which are then analyzed by electron microscopy to obtain morphological and structural information from a selected field of view at nm-scale resolution. Previously, an integrated approach to room temperature correlative microscopy was described. Combined use of light and electron microscopy within one instrument greatly simplifies sample handling, avoids cumbersome experimental overheads, simplifies navigation between the two modalities, and improves the success rate of image correlation. Here, an integrated approach for correlative microscopy under cryogenic conditions is presented. Its advantages over the room temperature approach include safeguarding the native hydrated state of the biological specimen, preservation of the fluorescence signal without risk of quenching due to heavy atom stains, and reduced photo bleaching. The potential of cryo integrated light and electron microscopy is demonstrated for the detection of viable bacteria, the study of in vitro polymerized microtubules, the localization of mitochondria in mouse embryonic fibroblasts, and for a search into virus-induced intracellular membrane modifications within mammalian cells. Copyright © 2012 Elsevier Inc. All rights reserved.

Improving the output voltage waveform of an intense electron-beam accelerator based on helical type Blumlein pulse forming line

Directory of Open Access Journals (Sweden)

Xin-Bing Cheng

2010-07-01

Full Text Available The Blumlein pulse forming line (BPFL consisting of an inner coaxial pulse forming line (PFL and an outer coaxial PFL is widely used in the field of pulsed power, especially for intense electron-beam accelerators (IEBA. The output voltage waveform determines the quality and characteristics of the output beam current of the IEBA. Comparing with the conventional BPFL, an IEBA based on a helical type BPFL can increase the duration of the output voltage in the same geometrical volume. However, for the helical type BPFL, the voltage waveform on a matched load may be distorted which influences the electron-beam quality. In this paper, an IEBA based on helical type BPFL is studied theoretically. Based on telegrapher equations of the BPFL, a formula for the output voltage of IEBA is obtained when the transition section is taken into account, where the transition section is between the middle cylinder of BPFL and the load. From the theoretical analysis, it is found that the wave impedance and transit time of the transition section influence considerably the main pulse voltage waveform at the load, a step is formed in front of the main pulse, and a sharp spike is also formed at the end of the main pulse. In order to get a well-shaped square waveform at the load and to improve the electron-beam quality of such an accelerator, the wave impedance of the transition section should be equal to that of the inner PFL of helical type BPFL and the transit time of the transition section should be designed as short as possible. Experiments performed on an IEBA with the helical type BPFL show reasonable agreement with theoretical analysis.

An atomic force microscopy-based method for line edge roughness measurement

Energy Technology Data Exchange (ETDEWEB)

Fouchier, M.; Pargon, E.; Bardet, B. [CNRS/UJF-Grenoble1/CEA LTM, 17 avenue des Martyrs, 38054 Grenoble cedex 9 (France)

2013-03-14

With the constant decrease of semiconductor device dimensions, line edge roughness (LER) becomes one of the most important sources of device variability and needs to be controlled below 2 nm for the future technological nodes of the semiconductor roadmap. LER control at the nanometer scale requires accurate measurements. We introduce a technique for LER measurement based upon the atomic force microscope (AFM). In this technique, the sample is tilted at about 45 Degree-Sign and feature sidewalls are scanned along their length with the AFM tip to obtain three-dimensional images. The small radius of curvature of the tip together with the low noise level of a laboratory AFM result in high resolution images. Half profiles and LER values on all the height of the sidewalls are extracted from the 3D images using a procedure that we developed. The influence of sample angle variations on the measurements is shown to be small. The technique is applied to the study of a full pattern transfer into a simplified gate stack. The images obtained are qualitatively consistent with cross-section scanning electron microscopy images and the average LER values agree with that obtained by critical dimension scanning electron microscopy. In addition to its high resolution, this technique presents several advantages such as the ability to image the foot of photoresist lines, complex multi-layer stacks regardless of the materials, and deep re-entrant profiles.

Effects of diffusion and surface interactions on the line shape of electron paramagnetic resonances in the presence of a magnetic field gradient

International Nuclear Information System (INIS)

Schaden, M.; Zhao, K. F.; Wu, Z.

2007-01-01

In an evanescent wave magnetometer the Zeeman polarization is probed at micrometer to submicrometer distances from the cell surface. The electron paramagnetic resonance lines of an evanescent wave magnetometer in the presence of a magnetic field gradient exhibit edge enhancement seen previously in nuclear magnetic resonance lines. We present a theoretical model that describes quantitatively the shape of the magnetic resonance lines of an evanescent wave magnetometer under a wide range of experimental conditions. It accounts for diffusion broadening in the presence of a magnetic field gradient as well as interactions of spin polarized Rb atoms with the coated Pyrex glass surfaces. Depending on the field gradient, cell thickness, and buffer gas pressure, the resonance line may have the form of a single asymmetric peak or two peaks localized near the front and back surfaces in frequency space. The double-peaked response depends on average characteristics of the surface interactions. Its shape is sensitive to the dwell time, relaxation probability, and average phase shift of adsorbed spin polarized Rb atoms

Development of on-line electrochemical sample pretreatment methods for the analysis of thallium and uranium by ICP-MS

International Nuclear Information System (INIS)

Zhou, F.; Van Berkel, G.J.; Morton, S.J.; Duckworth, D.C.; Adeniyi, W.K.; Keller, J.M.

1995-01-01

Anodic and adsorptive stripping voltammetry (AWV and AdSV, respectively) were performed on-line with a mercury thin-film electrode (MTFE) to effect the selective accumulation and detection of thallium and uranium, respectively. ASV-ICP-MS experiments using thallium as the test element were performed to characterize the behavior of the on-line system for low level and quantitative determinations. Excellent linearity in response was demonstrated for thallium standards ranging from 0.25 ng/L to 50 microg/L. The 1.0 pg/L detection limit calculated from this data for thallium (3σ/sensitivity) was 400 times lower than that of conventional ICP-MS. The ability to overcome sample matrix effects in quantitative determinations was demonstrated by the analysis of an undiluted synthetic urine sample. AdSV-ICP-MS experiments were performed using uranium as the test element to demonstrate the utility of this method for the determination of radiologically important elements. A uranium(VI)-cupferron complex was used to effect adsorptive accumulation of uranium from a 10 microg/L standard solution onto the MTFE. The uranium was chemically stripped from the electrode for subsequent downstream detection by the ICP-MS. The quantitative nature of this method and a modest enhancement of signal levels (∼X10) over those levels obtained with conventional ICP-MS for samples in the microgram/liter concentration range were demonstrated. Modifications to the current system to provide low flow rate operation will allow further optimization of the ASV-ICP-MS and AdSV-ICP-MS combinations

Tutoría on-line en el entorno universitario On-line tutoring at university: a proposal for the sequencing of electronic tools

Directory of Open Access Journals (Sweden)

Ainhoa Ezeiza Ramos

2007-10-01

Full Text Available El planteamiento consiste en proponer una manera de planificar algunas herramientas electrónicas presentes comúnmente en las plataformas de aprendizaje, ejemplificando cada caso de la secuencia con materiales reales de estudiantes de las titulaciones de Pedagogía y Psicopedagogía de la Universidad del País Vasco (UPV/EHU. Así, se pretende ofrecer una vía de reflexión acerca de la planificación y gestión de la acción tutorial on-line de asignatura. The main idea of this paper is to propose a way for planning some electronic tools which are currently present in e-learning platforms. Every step of the proposal is illustrated by a real example of students from the Education Degree Course or Psycho- Education Postgraduate Course of The University of The Basque Country. Thus, an attempt is made to offer a way to reflect on the planning and management of the online tutoring of the subject.

Observation of the two-electron cusp in atomic collisions. Evidence for strong electron-electron correlation

International Nuclear Information System (INIS)

Sarkadi, L.; Orban, A.

2007-01-01

Complete text of publication follows. In this report we present experimental data for a process when two electrons with velocity vectors equal to that of the projectile are emitted from collisions. By observing the two electron cusp the study of the threshold phenomenon for two-electron break-up is possible. It is a particularly interesting question whether the outgoing charged projectile can attract the two repulsing electrons so strongly that the two-electron cusp is formed. If it is so, a further question arises: Are the two electrons correlated in the final state as it is predicted by the Wannier theory? The experiments have been done at the 1 MeV VdG accelerator of ATOMKI using our TOF spectrometer. The first measurements clearly showed the formation of the two-electron cusp and signature of the electron correlation in 200 keV He 0 +He collisions. These promising results motivated us to carry out the experiment at 100 keV beam energy where the coincidence count rate is still reasonable but the energy resolution is better. For an acceptable data acquisition time we improved our data acquisition and data processing system for triple coincidence measurements. In Fig. 1a we present our measured relative fourfold differential cross section (FDCS) that shows strong electron correlation. For a comparison, in Fig. 1b we displayed the contour plot for uncorrelated electron pair emission. These latter data were synthesized artificially, generating the energies of the electron pairs from two independent double coincidence experiments. In both figures the distributions are characterized by two ridges. In Fig. 1b the ridges are perpendicular straight lines (E 1 = E 2 .13.6 eV). As a result of the correlation, the ridges in Fig. 1a are distorted in such a way that they have a joint straight-line section following the line E 1 + E 2 = 27.2 eV. This means that the electron pairs in the vicinity of the cusp maximum are emitted with a center of- mass velocity equal to that of

Atmospheric scanning electron microscope system with an open sample chamber: Configuration and applications

Energy Technology Data Exchange (ETDEWEB)

Nishiyama, Hidetoshi, E-mail: hinishiy@jeol.co.jp [JEOL Ltd., 3-1-2, Musashino, Akishima, Tokyo 196-8558 (Japan); Koizumi, Mitsuru, E-mail: koizumi@jeol.co.jp [JEOL Technics Ltd., 2-6-38 Musashino, Akishima, Tokyo 196-0021 (Japan); Ogawa, Koji, E-mail: kogawa@jeol.co.jp [JEOL Technics Ltd., 2-6-38 Musashino, Akishima, Tokyo 196-0021 (Japan); Kitamura, Shinich, E-mail: kitamura@jeol.co.jp [JEOL Ltd., 3-1-2, Musashino, Akishima, Tokyo 196-8558 (Japan); Konyuba, Yuji, E-mail: ykonyuub@jeol.co.jp [JEOL Ltd., 3-1-2, Musashino, Akishima, Tokyo 196-8558 (Japan); Watanabe, Yoshiyuki, E-mail: watanabeyoshiy@pref.yamagata.jp [Yamagata Research Institute of Technology, 2-2-1, Matsuei, Yamagata 990-2473 (Japan); Ohbayashi, Norihiko, E-mail: n.ohbayashi@m.tohoku.ac.jp [Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Fukuda, Mitsunori, E-mail: nori@m.tohoku.ac.jp [Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Suga, Mitsuo, E-mail: msuga@jeol.co.jp [JEOL Ltd., 3-1-2, Musashino, Akishima, Tokyo 196-8558 (Japan); Sato, Chikara, E-mail: ti-sato@aist.go.jp [Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-4, Umezono, Tsukuba 305-8568 (Japan)

2014-12-15

An atmospheric scanning electron microscope (ASEM) with an open sample chamber and optical microscope (OM) is described and recent developments are reported. In this ClairScope system, the base of the open sample dish is sealed to the top of the inverted SEM column, allowing the liquid-immersed sample to be observed by OM from above and by SEM from below. The optical axes of the two microscopes are aligned, ensuring that the same sample areas are imaged to realize quasi-simultaneous correlative microscopy in solution. For example, the cathodoluminescence of ZnO particles was directly demonstrated. The improved system has (i) a fully motorized sample stage, (ii) a column protection system in the case of accidental window breakage, and (iii) an OM/SEM operation system controlled by a graphical user interface. The open sample chamber allows the external administration of reagents during sample observation. We monitored the influence of added NaCl on the random motion of silica particles in liquid. Further, using fluorescence as a transfection marker, the effect of small interfering RNA-mediated knockdown of endogenous Varp on Tyrp1 trafficking in melanocytes was examined. A temperature-regulated titanium ASEM dish allowed the dynamic observation of colloidal silver nanoparticles as they were heated to 240 °C and sintered. - Highlights: • Atmospheric SEM (ASEM) allows observation of samples in liquid or gas. • Open sample chamber allows in situ monitoring of evaporation and sintering processes. • in situ monitoring of processes during reagent administration is also accomplished. • Protection system for film breakage is developed for ASEM. • Usability of ASEM has been improved significantly including GUI control.

Atmospheric scanning electron microscope system with an open sample chamber: Configuration and applications

International Nuclear Information System (INIS)

Nishiyama, Hidetoshi; Koizumi, Mitsuru; Ogawa, Koji; Kitamura, Shinich; Konyuba, Yuji; Watanabe, Yoshiyuki; Ohbayashi, Norihiko; Fukuda, Mitsunori; Suga, Mitsuo; Sato, Chikara

2014-01-01

An atmospheric scanning electron microscope (ASEM) with an open sample chamber and optical microscope (OM) is described and recent developments are reported. In this ClairScope system, the base of the open sample dish is sealed to the top of the inverted SEM column, allowing the liquid-immersed sample to be observed by OM from above and by SEM from below. The optical axes of the two microscopes are aligned, ensuring that the same sample areas are imaged to realize quasi-simultaneous correlative microscopy in solution. For example, the cathodoluminescence of ZnO particles was directly demonstrated. The improved system has (i) a fully motorized sample stage, (ii) a column protection system in the case of accidental window breakage, and (iii) an OM/SEM operation system controlled by a graphical user interface. The open sample chamber allows the external administration of reagents during sample observation. We monitored the influence of added NaCl on the random motion of silica particles in liquid. Further, using fluorescence as a transfection marker, the effect of small interfering RNA-mediated knockdown of endogenous Varp on Tyrp1 trafficking in melanocytes was examined. A temperature-regulated titanium ASEM dish allowed the dynamic observation of colloidal silver nanoparticles as they were heated to 240 °C and sintered. - Highlights: • Atmospheric SEM (ASEM) allows observation of samples in liquid or gas. • Open sample chamber allows in situ monitoring of evaporation and sintering processes. • in situ monitoring of processes during reagent administration is also accomplished. • Protection system for film breakage is developed for ASEM. • Usability of ASEM has been improved significantly including GUI control

Boosting Lyα and He II λ1640 Line Fluxes from Population III Galaxies: Stochastic IMF Sampling and Departures from Case-B

Science.gov (United States)

Mas-Ribas, Lluís; Dijkstra, Mark; Forero-Romero, Jaime E.

2016-12-01

We revisit calculations of nebular hydrogen Lyα and He II λ1640 line strengths for Population III (Pop III) galaxies, undergoing continuous, and bursts of, star formation. We focus on initial mass functions (IMFs) motivated by recent theoretical studies, which generally span a lower range of stellar masses than earlier works. We also account for case-B departures and the stochastic sampling of the IMF. In agreement with previous work, we find that departures from case-B can enhance the Lyα flux by a factor of a few, but we argue that this enhancement is driven mainly by collisional excitation and ionization, and not due to photoionization from the n = 2 state of atomic hydrogen. The increased sensitivity of the Lyα flux to the high-energy end of the galaxy spectrum makes it more subject to stochastic sampling of the IMF. The latter introduces a dispersion in the predicted nebular line fluxes around the deterministic value by as much as a factor of ˜4. In contrast, the stochastic sampling of the IMF has less impact on the emerging Lyman Werner photon flux. When case-B departures and stochasticity effects are combined, nebular line emission from Pop III galaxies can be up to one order of magnitude brighter than predicted by “standard” calculations that do not include these effects. This enhances the prospects for detection with future facilities such as the James Webb Space Telescope and large, ground-based telescopes.

Microdosimetry calculations for monoenergetic electrons using Geant4-DNA combined with a weighted track sampling algorithm.

Science.gov (United States)

Famulari, Gabriel; Pater, Piotr; Enger, Shirin A

2017-07-07

The aim of this study was to calculate microdosimetric distributions for low energy electrons simulated using the Monte Carlo track structure code Geant4-DNA. Tracks for monoenergetic electrons with kinetic energies ranging from 100 eV to 1 MeV were simulated in an infinite spherical water phantom using the Geant4-DNA extension included in Geant4 toolkit version 10.2 (patch 02). The microdosimetric distributions were obtained through random sampling of transfer points and overlaying scoring volumes within the associated volume of the tracks. Relative frequency distributions of energy deposition f(>E)/f(>0) and dose mean lineal energy ([Formula: see text]) values were calculated in nanometer-sized spherical and cylindrical targets. The effects of scoring volume and scoring techniques were examined. The results were compared with published data generated using MOCA8B and KURBUC. Geant4-DNA produces a lower frequency of higher energy deposits than MOCA8B. The [Formula: see text] values calculated with Geant4-DNA are smaller than those calculated using MOCA8B and KURBUC. The differences are mainly due to the lower ionization and excitation cross sections of Geant4-DNA for low energy electrons. To a lesser extent, discrepancies can also be attributed to the implementation in this study of a new and fast scoring technique that differs from that used in previous studies. For the same mean chord length ([Formula: see text]), the [Formula: see text] calculated in cylindrical volumes are larger than those calculated in spherical volumes. The discrepancies due to cross sections and scoring geometries increase with decreasing scoring site dimensions. A new set of [Formula: see text] values has been presented for monoenergetic electrons using a fast track sampling algorithm and the most recent physics models implemented in Geant4-DNA. This dataset can be combined with primary electron spectra to predict the radiation quality of photon and electron beams.

Breakdown of the independent electron picture in mesoscopic samples at low temperatures: The hunt for the Unicorn

Science.gov (United States)

Webb, R. A.

1998-03-01

A variety of experiments are discussed where, at low temperatures, it appears that the non-interacting picture of electrons in a Fermi liquid description of a mesoscopic sample is breaking down. Specifically, experiments on the temperature dependence of the phase-coherence time, energy relaxation rate, spin-flip scattering time, persistent currents in normal metals and transmission through a barrier in the fractional quantum Hall regime all display low-temperature properties which can not be accounted for in the independent electron picture.

Nebular and auroral emission lines of [Cl III] in the optical spectra of planetary nebulae.

Science.gov (United States)

Keenan, F P; Aller, L H; Ramsbottom, C A; Bell, K L; Crawford, F L; Hyung, S

2000-04-25

Electron impact excitation rates in Cl III, recently determined with the R-matrix code, are used to calculate electron temperature (T(e)) and density (N(e)) emission line ratios involving both the nebular (5517.7, 5537.9 A) and auroral (8433.9, 8480.9, 8500.0 A) transitions. A comparison of these results with observational data for a sample of planetary nebulae, obtained with the Hamilton Echelle Spectrograph on the 3-m Shane Telescope, reveals that the R(1) = I(5518 A)/I(5538 A) intensity ratio provides estimates of N(e) in excellent agreement with the values derived from other line ratios in the echelle spectra. This agreement indicates that R(1) is a reliable density diagnostic for planetary nebulae, and it also provides observational support for the accuracy of the atomic data adopted in the line ratio calculations. However the [Cl iii] 8433.9 A line is found to be frequently blended with a weak telluric emission feature, although in those instances when the [Cl iii] intensity may be reliably measured, it provides accurate determinations of T(e) when ratioed against the sum of the 5518 and 5538 A line fluxes. Similarly, the 8500.0 A line, previously believed to be free of contamination by the Earth's atmosphere, is also shown to be generally blended with a weak telluric emission feature. The [Cl iii] transition at 8480.9 A is found to be blended with the He i 8480.7 A line, except in planetary nebulae that show a relatively weak He i spectrum, where it also provides reliable estimates of T(e) when ratioed against the nebular lines. Finally, the diagnostic potential of the near-UV [Cl iii] lines at 3344 and 3354 A is briefly discussed.

The IFUSP microtron accelerator beam transport line

International Nuclear Information System (INIS)

Rios, Paulo Beolchi

2002-01-01

In this work, the electron optical project of the IFUSP microtron beam transport line is presented, including the operational values for the parameters of the dipolar and quadrupolar electromagnets, as well as their location along the beam line. Analytical calculations and computer simulations were performed to obtain these results, and a programming tool was developed in order to analyze the beam parameters and to help studying racetrack microtrons. The electron optical simulations were split into two different study cases: the microtron booster, and the transfer line. In the first case, it was determined the main operational parameters of a microtron working far from its usual stability conditions. In the latter, it was done the basic design of the linking line between the booster and main (not yet built) microtrons, and between them and the experimental hall, with a total path length of approximately 32 m including large horizontal and vertical deflections with variable beam energy. (author)

Los resonance lines in promethiumlike heavy ions

International Nuclear Information System (INIS)

Nakamura, Nobuyuki; Kobayashi, Yusuke; Kato, Daiji; Sakaue, Hiroyuki A.; Murakami, Izumi

2016-01-01

Identifying the ns - np resonance lines in alkali-metal-like ions is an important issue in fusion plasma science in the view of spectroscopic diagnostics and radiation power loss. Whereas for n=2, 3 and 4 these resonances are prominent and well studied, so far no one could clearly identify the resonance lines for n=5 in the promethiumlike sequence. We have now experimentally clarified the reason for the 'lost resonance lines. In the present study, highly-charged bismuth ions have been studied using a compact electron beam ion trap (EBIT). Extreme ultraviolet emission from the bismuth ions produced and trapped in the EBIT is observed with a grazing-incidence flat-field spectrometer. The energy dependent spectra are compared with a collisional-radiative model calculation, and we show that the 5s - 5p resonance lines are very weak in plasma with a wide range of electron density due to the presence of a long-lived metastable state. (author)

Magnetization of topological line-node semimetals

Science.gov (United States)

Mikitik, G. P.; Sharlai, Yu. V.

2018-02-01

Using an approximate expression for the Landau levels of the electrons located near a nodal line of a topological line-node semimetal, we obtain formulas for the magnetization of this semimetal at an arbitrary shape of its line. It is also shown that the dependence of the chemical potential on the magnetic field can be strong in these materials, and this dependence can essentially influence the de Haas-van Alphen oscillations. The obtained results are applied to the rhombohedral graphite, which is one of the line-node semimetals. For this material, we find temperature and magnetic field dependencies of its magnetic susceptibility.

Double differential distributions of electron emission in ion-atom and electron-atom collisions using an electron spectrometer

International Nuclear Information System (INIS)

Misra, Deepankar; Thulasiram, K.V.; Fernandes, W.; Kelkar, Aditya H.; Kadhane, U.; Kumar, Ajay; Singh, Yeshpal; Gulyas, L.; Tribedi, Lokesh C.

2009-01-01

We study electron emission from atoms and molecules in collisions with fast electrons and heavy ions (C 6+ ). The soft collision electrons (SE), two center electron emission (TCEE), the binary encounter (BE) events and the KLL Auger lines along with the elastically scattered peaks (in electron collisions) are studied using a hemispherical electrostatic electron analyzer. The details of the measurements along with description of the spectrometer and data acquisition system are given. The angular distributions of the low energy (few eV) electrons in soft collisions and the binary encounter electrons at keV energies are compared with quantum mechanical models based on the first Born (B1) and the continuum distorted wave-Eikonal initial state approximation (CDW-EIS).

Analytic calculation of radiative-recoil corrections to muonium hyperfine splitting: Electron-line contribution

International Nuclear Information System (INIS)

Eides, M.I.; Karshenboim, S.G.; Shelyuto, V.A.

1991-01-01

The detailed account of analytic calculation of radiative-recoil correction to muonium hyperfine splitting, induced by electron-line radiative insertions, is presented. The consideration is performed in the framework of the effective two-particle formalism. A good deal of attention is paid to the problem of the divergence cancellation and the selection of graphs, relevant to radiative-recoil corrections. The analysis is greatly facilitated by use of the Fried-Yennie gauge for radiative photons. The obtained set of graphs turns out to be gauge-invariant and actual calculations are performed in the Feynman gauge. The main technical tricks, with the help of which we have effectively utilized the existence in the problem of the small parameter-mass ratio and managed to perform all calculations in the analytic form are described. The main intermediate results, as well as the final answer, δE rr = (α(Ζα)/π 2 )(m/M)E F (6ζ(3) + 3π 2 In 2 + π 2 /2 + 17/8), are also presented

Scanning Electron Microscopy with Samples in an Electric Field

Czech Academy of Sciences Publication Activity Database

Frank, Luděk; Hovorka, Miloš; Mikmeková, Šárka; Mikmeková, Eliška; Müllerová, Ilona; Pokorná, Zuzana

2012-01-01

Roč. 5, č. 12 (2012), s. 2731-2756 ISSN 1996-1944 R&D Projects: GA ČR GAP108/11/2270; GA TA ČR TE01020118; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : scanning electron microscopy * slow electrons * low energy SEM * low energy STEM * cathode lens Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 2.247, year: 2012

Collisional effects in He I lines and helium abundances in planetary nebulae

International Nuclear Information System (INIS)

Clegg, R.E.S.

1987-01-01

Attention is drawn to new, 19-state quantal calculations for collisional excitation by electron impact in neutral helium. Recommended empirical formulae are given for the collisional contribution to HeI recombination lines such as λλ4471, 5876 A in gaseous nebulae. Collisional ionization of metastable (2 3 S) He I is significant for high-temperature nebulae. Collisional transfers provide significant cooling in nebulae with low heavy-element abundances. Revised mean He/H ratios for three large samples of planetary nebulae are given. (author)

Sample preparation technique for transmission electron microscopy anodized Al-Li-SiC metal matrix composite

International Nuclear Information System (INIS)

Shahid, M.; Thomson, G.E.

1997-01-01

Along with improved mechanical properties, metal matrix composites (MMC) have a disadvantage of enhanced corrosion susceptibility in aggressive environments. Recent studies on corrosion behaviour of an Al-alloy 8090/SiC MMC, revealed considerably high corrosion rates of the MMC in near neutral solutions containing chloride ions. Anodizing is one of the potential surface treatment for the MMC to provide protective coating against corrosion. The surface and cross section of the anodized MMC can easily be observed using scanning electron microscope. The anodizing behaviour of the MMC can be understood further if the anodized cross section in examined under transmission electron microscope (TEM). However, it is relatively difficult to prepare small (3 mm diameter) electron transparent specimens of the MMC supporting an anodic film. In the present study a technique has been developed for preparing thin electron transparent specimens of the anodized MMC. This technique employed conventional ion beam thinning process but the preparation of small discs was a problem. A MMMC consisting of Al-alloy 8090 with 20 % (by weight) SiC particulate with an average size of 5 Mu m, was anodized and observed in TEM after preparing the samples using the above mentioned techniques. (author)

Study of pitting corrosion in line-pipe steel under the influence of remanent magnetization

Energy Technology Data Exchange (ETDEWEB)

Espina-Hernandez, J H; Caleyo, F; Hallen, J M [Instituto Politecnico Nacional (IPN), Zacatenco (Mexico)

2009-07-01

The influence of remanent magnetization on pitting corrosion in line-pipe steels is studied. Pitting corrosion experiments have been carried out on samples of an API 5L grade 52 steel under a magnetization level of the same order of magnitude of the remanent magnetization in the pipeline wall after in-line inspection based on magnetic flux leakage. The samples were magnetized using rings of the same grade as the investigated steel. Immediately after magnetization, the investigated samples were subjected to pitting by immersing them in a solution containing dissolved Cl{sup -} and SO{sup 2-}{sub 4} and ions. The pitting experiments were conducted during a seven days period. The pit depth distribution and the maximum pit depth in each sample were recorded and used to conduct extreme value analyses of the pitting process in magnetized and non-magnetized control samples. The statistical assessment of the pitting corrosion data collected during this study shows that the magnetic field reduces the average depth of the pit population and also the extreme pit depth values that can be predicted from the maximum values observed in the magnetized samples in comparison with to the non-magnetized control samples. Scanning electron microscopy observations show that the magnetic field alters the pit morphology by increasing the pit mouth opening. (author)

Differential phase-contrast dark-field electron holography for strain mapping

Energy Technology Data Exchange (ETDEWEB)

Denneulin, Thibaud, E-mail: thibaud.denneulin@cemes.fr; Houdellier, Florent, E-mail: florent.houdellier@cemes.fr; Hÿtch, Martin, E-mail: martin.hytch@cemes.fr

2016-01-15

Strain mapping is an active area of research in transmission electron microscopy. Here we introduce a dark-field electron holographic technique that shares several aspects in common with both off-axis and in-line holography. Two incident and convergent plane waves are produced in front of the specimen thanks to an electrostatic biprism in the condenser system of a transmission electron microscope. The interference of electron beams diffracted by the illuminated crystal is then recorded in a defocused plane. The differential phase recovered from the hologram is directly proportional to the strain in the sample. The strain can be quantified if the separation of the images due to the defocus is precisely determined. The present technique has the advantage that the derivative of the phase is measured directly which allows us to avoid numerical differentiation. The distribution of the noise in the reconstructed strain maps is isotropic and more homogeneous. This technique was used to investigate different samples: a Si/SiGe superlattice, transistors with SiGe source/drain and epitaxial PZT thin films. - Highlights: • DPC dark-field electron holography is set up with a condenser biprism. • The DPC phase is directly proportional to the lattice deformation. • The technique is illustrated with epitaxial SiGe and Pb(Zr,Ti)O{sub 3} samples. • The defocus allows us to control the strain sensitivity and the spatial resolution. • A solution is proposed to setup this technique with a post-specimen biprism.

On-line database of the spectral properties of polycyclic aromatic hydrocarbons

International Nuclear Information System (INIS)

Malloci, Giuliano; Joblin, Christine; Mulas, Giacomo

2007-01-01

We present an on-line database of computed molecular properties for a large sample of polycyclic aromatic hydrocarbons in four charge states: -1, 0, +1, and +2. At present our database includes 40 molecules ranging in size from naphthalene and azulene (C 10 H 8 ) up to circumovalene (C 66 H 20 ). We performed our calculations in the framework of the density functional theory (DFT) and the time-dependent DFT to obtain the most relevant molecular parameters needed for astrophysical applications. For each molecule in the sample, our database presents in a uniform way the energetic, rotational, vibrational, and electronic properties. It is freely accessible on the web at (http://astrochemistry.ca.astro.it/database/) and (http://www.cesr.fr/~joblin/database/)

LABORATORY MEASUREMENTS OF WHITE DWARF PHOTOSPHERIC SPECTRAL LINES: Hβ

International Nuclear Information System (INIS)

Falcon, Ross E.; Gomez, T. A.; Montgomery, M. H.; Winget, D. E.; Rochau, G. A.; Bailey, J. E.; Nagayama, T.

2015-01-01

We spectroscopically measure multiple hydrogen Balmer line profiles from laboratory plasmas to investigate the theoretical line profiles used in white dwarf (WD) atmosphere models. X-ray radiation produced at the Z Pulsed Power Facility at Sandia National Laboratories initiates plasma formation in a hydrogen-filled gas cell, replicating WD photospheric conditions. Here we present time-resolved measurements of Hβ and fit this line using different theoretical line profiles to diagnose electron density, n e , and n = 2 level population, n 2 . Aided by synthetic tests, we characterize the validity of our diagnostic method for this experimental platform. During a single experiment, we infer a continuous range of electron densities increasing from n e ∼ 4 to ∼30 × 10 16 cm −3 throughout a 120-ns evolution of our plasma. Also, we observe n 2 to be initially elevated with respect to local thermodynamic equilibrium (LTE); it then equilibrates within ∼55 ns to become consistent with LTE. This supports our electron-temperature determination of T e ∼ 1.3 eV (∼15,000 K) after this time. At n e ≳ 10 17 cm −3 , we find that computer-simulation-based line-profile calculations provide better fits (lower reduced χ 2 ) than the line profiles currently used in the WD astronomy community. The inferred conditions, however, are in good quantitative agreement. This work establishes an experimental foundation for the future investigation of relative shapes and strengths between different hydrogen Balmer lines

Interfacial electronic charge transfer and density of states in short period Cu/Cr multilayers; TOPICAL

International Nuclear Information System (INIS)

Barbee, T W; Bello, A F; Klepeis, J E; Van Buuren, T

1999-01-01

Nanometer period metallic multilayers are ideal structures to investigate electronic phenomena at interfaces between metal films since interfacial atoms comprise a large atomic fraction of the samples. The Cu/Cr binary pair is especially suited to study the interfaces in metals since these elements are mutually insoluble, thus eliminating mixing effects and compound formation and the lattice mismatch is very small. This allows the fabrication of high structural quality Cu/Cr multilayers that have a structure which can be approximated in calculations based on idealized atomic arrangements. The electronic structure of the Cu and the Cr layers in several samples of thin Cu/Cr multilayers were studied using x-ray absorption spectroscopy (XAS). Total electron yield was measured and used to study the white lines at the Cu L(sub 2) and L(sub 3) absorption edges. The white lines at the Cu absorption edges are strongly related to the unoccupied d-orbitals and are used to calculate the amount of charge transfer between the Cr and Cu atoms in interfaces. Analysis of the Cu white lines show a charge transfer of 0.026 electrons/interfacial Cu atom to the interfacial Cr atoms. In the Cu XAS spectra we also observe a van Hove singularity between the L(sub 2) and L(sub 3) absorption edges as expected from the structural analysis. The absorption spectra are compared to partial density of states obtained from a full-potential linear muffin-tin orbital calculation. The calculations support the presence of charge transfer and indicate that it is localized to the first two interfacial layers in both Cu and Cr

On-line sample processing methods in flow analysis

DEFF Research Database (Denmark)

Miró, Manuel; Hansen, Elo Harald

2008-01-01

In this chapter, the state of the art of flow injection and related approaches thereof for automation and miniaturization of sample processing regardless of the aggregate state of the sample medium is overviewed. The potential of the various generation of flow injection for implementation of in...

SPECTROSCOPIC DIAGNOSIS IN ELECTRONIC TEMPERATURE OF PHOTOIONISE PLASMAS

Directory of Open Access Journals (Sweden)

A. K. Ferouani

2015-08-01

Full Text Available In this work, we are interested in the diagnostics in electronic temperature of a plasma purely photoionized, based on the intensity ration of lines emitted by ions helium-like, which have an atomic number Z relatively small. We considered the three lines corresponding to the transitions starting from the excited levels 1s2l towards the fundamental level 1s2 1S0, like appropriate lines. More precisely, the line of resonance w due to the transition 1s2p 1P1 --- 1s2 1 S0, the line of intercombinaison (x,y 1s2p 3 P2,1 --- 1s2 1 S0  as well as prohibited line z due to the transition 1s2 3 S1 --- 1s2 1 S0. These lines appear clearly in the spectra of astrophysical plasmas. As helium-like ion, we chose two, the oxygen O6+ (Z=8 and neon Ne8+ (Z=10. We carried out calculations of the ration of lines intensity G=(z+x+y/w of O6+ and Ne8+  according to the electronic temperature in the range going from 105 to 107 K. We will see that, like it was shown by Gabriel and Jordan in 1969 [1], this intensity ration can be very sensitive to the temperature electronic and practically independent of the electronic density. Consequently, the ration G can be used to determine in a reliable way the electronic temperature of plasma observed [2].

BROAD ABSORPTION LINE VARIABILITY ON MULTI-YEAR TIMESCALES IN A LARGE QUASAR SAMPLE

Energy Technology Data Exchange (ETDEWEB)

Filiz Ak, N.; Brandt, W. N.; Schneider, D. P. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Hall, P. B. [Department of Physics and Astronomy, York University, 4700 Keele St., Toronto, Ontario, M3J 1P3 (Canada); Anderson, S. F. [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Hamann, F. [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Lundgren, B. F. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Pâris, I. [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Petitjean, P. [Universite Paris 6, Institut d' Astrophysique de Paris, 75014, Paris (France); Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 92420 (United States); Shen, Yue [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS-51, Cambridge, MA 02138 (United States); York, Don, E-mail: nfilizak@astro.psu.edu [The University of Chicago, Department of Astronomy and Astrophysics, Chicago, IL 60637 (United States)

2013-11-10

We present a detailed investigation of the variability of 428 C IV and 235 Si IV broad absorption line (BAL) troughs identified in multi-epoch observations of 291 quasars by the Sloan Digital Sky Survey-I/II/III. These observations primarily sample rest-frame timescales of 1-3.7 yr over which significant rearrangement of the BAL wind is expected. We derive a number of observational results on, e.g., the frequency of BAL variability, the velocity range over which BAL variability occurs, the primary observed form of BAL-trough variability, the dependence of BAL variability upon timescale, the frequency of BAL strengthening versus weakening, correlations between BAL variability and BAL-trough profiles, relations between C IV and Si IV BAL variability, coordinated multi-trough variability, and BAL variations as a function of quasar properties. We assess implications of these observational results for quasar winds. Our results support models where most BAL absorption is formed within an order-of-magnitude of the wind-launching radius, although a significant minority of BAL troughs may arise on larger scales. We estimate an average lifetime for a BAL trough along our line-of-sight of a few thousand years. BAL disappearance and emergence events appear to be extremes of general BAL variability, rather than being qualitatively distinct phenomena. We derive the parameters of a random-walk model for BAL EW variability, finding that this model can acceptably describe some key aspects of EW variability. The coordinated trough variability of BAL quasars with multiple troughs suggests that changes in 'shielding gas' may play a significant role in driving general BAL variability.

Electronical set-up and on-line data processing for the determination of the cross section of the reaction 1H(n,d)γ

International Nuclear Information System (INIS)

Hutsch, J.; Moesner, J.; Schmidt, G.; Stiehler, T.; Kudin, L.G.; Spiridenkov, E.M.; Volkov, S.S.

1982-01-01

After a brief description of the physical problem the electronical set-up for the investigation of the reaction 1 H(n,d)γ at Esub(n) = 25 MeV and the connection with the on-line computer are described in the first part of the present work. The second part includes the software and the data handling. (author)

An OCD perspective of line edge and line width roughness metrology

Science.gov (United States)

Bonam, Ravi; Muthinti, Raja; Breton, Mary; Liu, Chi-Chun; Sieg, Stuart; Seshadri, Indira; Saulnier, Nicole; Shearer, Jeffrey; Patlolla, Raghuveer; Huang, Huai

2017-03-01

Metrology of nanoscale patterns poses multiple challenges that range from measurement noise, metrology errors, probe size etc. Optical Metrology has gained a lot of significance in the semiconductor industry due to its fast turn around and reliable accuracy, particularly to monitor in-line process variations. Apart from monitoring critical dimension, thickness of films, there are multiple parameters that can be extracted from Optical Metrology models3. Sidewall angles, material compositions etc., can also be modeled to acceptable accuracy. Line edge and Line Width roughness are much sought of metrology following critical dimension and its uniformity, although there has not been much development in them with optical metrology. Scanning Electron Microscopy is still used as a standard metrology technique for assessment of Line Edge and Line Width roughness. In this work we present an assessment of Optical Metrology and its ability to model roughness from a set of structures with intentional jogs to simulate both Line edge and Line width roughness at multiple amplitudes and frequencies. We also present multiple models to represent roughness and extract relevant parameters from Optical metrology. Another critical aspect of optical metrology setup is correlation of measurement to a complementary technique to calibrate models. In this work, we also present comparison of roughness parameters extracted and measured with variation of image processing conditions on a commercially available CD-SEM tool.

Establishment of an agamid cell line and isolation of adenoviruses from central bearded dragons (Pogona vitticeps).

Science.gov (United States)

Ball, Inna; Hoferer, Marc; Marschang, Rachel E

2014-03-01

A cell line was established from whole 6-8-week-old central bearded dragon (Pogona vitticeps) embryos. Cells were mid-sized and showed an elongated and polymorphic form. The cell line grew in a monolayer and has been serially passaged for 17 passages at time of publication. This cell line has been used with samples from adenovirus polymerase chain reaction (PCR)-positive bearded dragons, and 2 virus isolates have been obtained so far. The isolates show a clear cytopathic effect in inoculated cells. Both virus isolates have been serially passaged on this cell line, and have been identified by PCR amplification and sequencing of a portion of the DNA-dependent DNA polymerase gene and show 100% nucleotide identity to the corresponding region of an agamid adenovirus. Electron microscopic examination of supernatant from infected cells demonstrated the presence of nonenveloped particles, with a diameter of approximately 80 nm in both virus isolates.

Field-Lines-Threaded Model for: (1) the Low Solar Corona; (2) Electrons in the Transition Region; and (3) Solar Energetic Particle Acceleration and Transport

Science.gov (United States)

Sokolov, I.; van der Holst, B.; Jin, M.; Gombosi, T. I.; Taktakishvili, A.; Khazanov, G. V.

2013-12-01

In numerical simulations of the solar corona, both for the ambient state and especially for dynamical processes the most computational resources are spent for maintaining the numerical solution in the Low Solar Corona and in the transition region, where the temperature gradients are very sharp and the magnetic field has a complicated topology. The degraded computational efficiency is caused by the need in a highest resolution as well as the use of the fully three-dimensional implicit solver for electron heat conduction. On the other hand, the physical nature of the processes involved is rather simple (which still does not facilitate the numerical methods) as long as the heat fluxes as well as slow plasma motional velocities are aligned with the magnetic field. The Alfven wave turbulence, which is often believed to be the main driver of the solar wind and the main source of the coronal heating, is characterized by the Poynting flux of the waves, which is also aligned with the magnetic field. Therefore, the plasma state in any point of the three-dimensional grid in the Low Solar Corona can be found by solving a set of one-dimensional equations for the magnetic field line ('thread'), which passes through this point and connects it to the chromosphere and to the global Solar Corona. In the present paper we describe an innovative computational technology based upon the use of the magnetic-field-line-threads to find the local solution. We present the development of the AWSoM code of the University of Michigan with the field-lines-threaded Low Solar Corona. In the transition region, where the essentially kinetic description of the electron energy fluxes is required, we solve the Fokker-Plank equation on the system of threads, to achieve the physically consistent description of chromosphere evaporation. The third application for the field-lines-treaded model is the Solar Energetic Particle (SEP) acceleration and transport. Being the natural extension of the Field-Line

Electronics pocket book

CERN Document Server

Parr, E A

1981-01-01

Electronics Pocket Book, Fourth Edition is a nonmathematical presentation of the many varied topics covered by electronics. The book tackles electron physics, electronic components (i.e. resistors, capacitors, and conductors), integrated circuits, and the principles of a.c. and d.c. amplifiers. The text also discusses oscillators, digital circuits, digital computers, and optoelectronics (i.e., sensors, emitters, and devices that utilize light). Communications (such as line and radio communications, transmitters, receivers, and digital techniques); the principles and examples of servosystems; a

``Low-cost Electronic nose evaluated on Thai-herb of Northern-Thailand samples using multivariate analysis methods''

Science.gov (United States)

na ayudhaya, Paisarn Daungjak; Klinbumrung, Arrak; Jaroensutasinee, Krisanadej; Pratontep, Sirapat; Kerdcharoen, Teerakiat

2009-05-01

In case of species of natural and aromatic plant originated from the northern Thailand, sensory characteristics, especially odours, have unique identifiers of herbs. The instruments sensory analysis have performed by several of differential of sensing, so call `electronic nose', to be a significantly and rapidly for chemometrics. The signal responses of the low cost electronic nose were evaluated by principal component analysis (PCA). The aims of this paper evaluated various of Thai-herbs grown in Northern of Thailand as data preprocessing tools of the Low-cost electronic nose (enNU-PYO1). The essential oil groups of Thai herbs such as Garlic, Lemongrass, Shallot (potato onion), Onion, Zanthoxylum limonella (Dennst.) Alston (Thai name is Makaen), and Kaffir lime leaf were compared volatilized from selected fresh herbs. Principal component analysis of the original sensor responses did clearly distinguish either all samples. In all cases more than 97% for cross-validated group were classified correctly. The results demonstrated that it was possible to develop in a model to construct a low-cost electronic nose to provide measurement of odoriferous herbs.

Beam instrumentation for the BNL Heavy Ion Transfer Line

International Nuclear Information System (INIS)

Witkover, R.L.; Buxton, W.; Castillo, V.; Feigenbaum, I.; Lazos, A.; Li, Z.G.; Smith, G.; Stoehr, R.

1987-01-01

The Heavy Ion Transfer Line (HITL) was constructed to transport beams from the BNL Tandem Van de Graaff (TVDG) to be injected into the AGS. Because the beam line is approximately 2000 feet long and the particle rigidity is so low, 20 beam monitor boxes were placed along the line. The intensity ranges from 1 to 100 nanoAmps for the dc trace beam used for line set-up, to over 100 μA for the pulsed beam to be injected into the AGS. Profiles are measured using multiwire arrays (HARPS) while Faraday cups and beam transformers monitor the intensity. The electronics stations are operated through 3 Instrumentation Controllers networked to Apollo workstations in the TVDG and AGS control rooms. Details of the detectors and electronics designs and performance will be given

Liquid sampling-atmospheric pressure glow discharge as a secondary excitation source: Assessment of plasma characteristics

Science.gov (United States)

Manard, Benjamin T.; Gonzalez, Jhanis J.; Sarkar, Arnab; Dong, Meirong; Chirinos, Jose; Mao, Xianglei; Russo, Richard E.; Marcus, R. Kenneth

The liquid sampling-atmospheric pressure glow discharge (LS-APGD) has been assessed as a secondary excitation source with a parametric evaluation regarding carrier gas flow rate, applied current, and electrode distance. With this parametric evaluation, plasma optical emission was monitored in order to obtain a fundamental understanding with regards to rotational temperature (Trot), excitation temperature (Texc), electron number density (ne), and plasma robustness. Incentive for these studies is not only for a greater overall fundamental knowledge of the APGD, but also in instrumenting a secondary excitation/ionization source following laser ablation (LA). Rotational temperatures were determined through experimentally fitting of the N2 and OH molecular emission bands while atomic excitation temperatures were calculated using a Boltzmann distribution of He and Mg atomic lines. The rotational and excitation temperatures were determined to be ~ 1000 K and ~ 2700 K respectively. Electron number density was calculated to be on the order of ~ 3 × 1015 cm- 3 utilizing Stark broadening effects of the Hα line of the Balmer series and a He I transition. In addition, those diagnostics were performed introducing magnesium (by solution feed and laser ablation) into the plasma in order to determine any perturbation under heavy matrix sampling. The so-called plasma robustness factor, derived by monitoring Mg II/Mg I emission ratios, is also employed as a reflection of potential perturbations in microplasma energetics across the various operation conditions and sample loadings. While truly a miniaturized source (laser ablation sample introduction.

INDRA. Electronic Architecture

International Nuclear Information System (INIS)

Ganil Team.

1993-01-01

The INDRA multidetector electronics is described. The system is a set of 17 rings consisting of 96 ionization chambers and 180 silicon detectors plus 324 cesium iodide and 12 Phoswich scintillators. Their integrated electronic lines, the trigger modules, the control and data acquisition units are presented briefly. (R.P.) 6 figs

Identification of a novel rhabdovirus in Spodoptera frugiperda cell lines.

Science.gov (United States)

Ma, Hailun; Galvin, Teresa A; Glasner, Dustin R; Shaheduzzaman, Syed; Khan, Arifa S

2014-06-01

The Sf9 cell line, derived from Spodoptera frugiperda, is used as a cell substrate for biological products, and no viruses have been reported in this cell line after extensive testing. We used degenerate PCR assays and massively parallel sequencing (MPS) to identify a novel RNA virus belonging to the order Mononegavirales in Sf9 cells. Sequence analysis of the assembled virus genome showed the presence of five open reading frames (ORFs) corresponding to the genes for the N, P, M, G, and L proteins in other rhabdoviruses and an unknown ORF of 111 amino acids located between the G- and L-protein genes. BLAST searches indicated that the S. frugiperda rhabdovirus (Sf-rhabdovirus) was related in a limited region of the L-protein gene to Taastrup virus, a newly discovered member of the Mononegavirales from a leafhopper (Hemiptera), and also to plant rhabdoviruses, particularly in the genus Cytorhabdovirus. Phylogenetic analysis of sequences in the L-protein gene indicated that Sf-rhabdovirus is a novel virus that branched with Taastrup virus. Rhabdovirus morphology was confirmed by transmission electron microscopy of filtered supernatant samples from Sf9 cells. Infectivity studies indicated potential transient infection by Sf-rhabdovirus in other insect cell lines, but there was no evidence of entry or virus replication in human cell lines. Sf-rhabdovirus sequences were also found in the Sf21 parental cell line of Sf9 cells but not in other insect cell lines, such as BT1-TN-5B1-4 (Tn5; High Five) cells and Schneider's Drosophila line 2 [D.Mel.(2); SL2] cells, indicating a species-specific infection. The results indicate that conventional methods may be complemented by state-of-the-art technologies with extensive bioinformatics analysis for identification of novel viruses. The Spodoptera frugiperda Sf9 cell line is used as a cell substrate for the development and manufacture of biological products. Extensive testing has not previously identified any viruses in this cell

Correlations in the quantum theory of plasma line broadening

International Nuclear Information System (INIS)

Dufty, J.W.; Boercker, D.B.

1976-01-01

A unified theory of plasma line broadening is obtained from a quantum kinetic equation, paralleling existing results for a classical plasma. The atom-electron interactions are shielded by equilibrium electron correlation functions and a frequency dependent dielectric function. A 'ring' approximation is used to replace the classical plasma parameter expansion, for typical laboratory conditions. Atom-electron correlations are included as well as electron-electron correlations. (author)

BOOSTING LY α   AND He ii λ 1640 LINE FLUXES FROM POPULATION III GALAXIES: STOCHASTIC IMF SAMPLING AND DEPARTURES FROM CASE-B

International Nuclear Information System (INIS)

Mas-Ribas, Lluís; Dijkstra, Mark; Forero-Romero, Jaime E.

2016-01-01

We revisit calculations of nebular hydrogen Ly α and He ii λ 1640 line strengths for Population III (Pop III) galaxies, undergoing continuous, and bursts of, star formation. We focus on initial mass functions (IMFs) motivated by recent theoretical studies, which generally span a lower range of stellar masses than earlier works. We also account for case-B departures and the stochastic sampling of the IMF. In agreement with previous work, we find that departures from case-B can enhance the Ly α flux by a factor of a few, but we argue that this enhancement is driven mainly by collisional excitation and ionization, and not due to photoionization from the n  = 2 state of atomic hydrogen. The increased sensitivity of the Ly α flux to the high-energy end of the galaxy spectrum makes it more subject to stochastic sampling of the IMF. The latter introduces a dispersion in the predicted nebular line fluxes around the deterministic value by as much as a factor of ∼4. In contrast, the stochastic sampling of the IMF has less impact on the emerging Lyman Werner photon flux. When case-B departures and stochasticity effects are combined, nebular line emission from Pop III galaxies can be up to one order of magnitude brighter than predicted by “standard” calculations that do not include these effects. This enhances the prospects for detection with future facilities such as the James Webb Space Telescope and large, ground-based telescopes.

Study of the Auger line shape of polyethylene and diamond

Energy Technology Data Exchange (ETDEWEB)

Dayan, M; Pepper, S V

1984-03-01

The KVV Auger electron line shapes of carbon in polyethylene and diamond have been studied. The spectra were obtained in derivative form by electron beam excitation. They were treated by background subtraction, integration and deconvolution to produce the intrinsic Auger line shape. Electron energy loss spectra provided the response function in the deconvolution procedure. The line shape from polyethylene is compared with spectra from linear alkanes and with a previous spectrum of Kelber et al. Both spectra are compared with the self-convolution of their full valence band densities of states and of their p-projected densities. The experimental spectra could not be understood in terms of existing theories. This is so even when correlation effects are qualitatively taken into account according to the theories of Cini and Sawatzky and Lenselink.

Adherence to active play and electronic media guidelines in preschool children: gender and parental education considerations.

Science.gov (United States)

Loprinzi, Paul D; Schary, David P; Cardinal, Bradley J

2013-01-01

The primary purpose of the present study was to examine adherence to current active play and electronic media use guidelines in a sample of US preschool-aged children and to examine whether differences occurred across gender and parental education. 164 parents completed an on-line survey to estimate preschool children's active play and sedentary behaviors. For weekdays, 50% of the sample met the active play guideline with this increasing to 65% during the weekend. With respect to electronic media use, 90% of the sample met guidelines during the week, with the percentage meeting guidelines dropping to 78% during the weekend. A greater percentage of preschool children from high parental education families (83.4 ± 3.3) met electronic media use guidelines on the weekends, compared to preschool children from low parental education families (59.4 ± 8.1) (p = 0.002). Our findings indicate that a substantial portion of preschool children are not meeting active play guidelines and that adherence to active play and electronic media use guidelines may be influenced by parental education.

Automation and integration of multiplexed on-line sample preparation with capillary electrophoresis for DNA sequencing

Energy Technology Data Exchange (ETDEWEB)

Tan, H.

1999-03-31

The purpose of this research is to develop a multiplexed sample processing system in conjunction with multiplexed capillary electrophoresis for high-throughput DNA sequencing. The concept from DNA template to called bases was first demonstrated with a manually operated single capillary system. Later, an automated microfluidic system with 8 channels based on the same principle was successfully constructed. The instrument automatically processes 8 templates through reaction, purification, denaturation, pre-concentration, injection, separation and detection in a parallel fashion. A multiplexed freeze/thaw switching principle and a distribution network were implemented to manage flow direction and sample transportation. Dye-labeled terminator cycle-sequencing reactions are performed in an 8-capillary array in a hot air thermal cycler. Subsequently, the sequencing ladders are directly loaded into a corresponding size-exclusion chromatographic column operated at {approximately} 60 C for purification. On-line denaturation and stacking injection for capillary electrophoresis is simultaneously accomplished at a cross assembly set at {approximately} 70 C. Not only the separation capillary array but also the reaction capillary array and purification columns can be regenerated after every run. DNA sequencing data from this system allow base calling up to 460 bases with accuracy of 98%.

Forensic Scanning Electron Microscope

Science.gov (United States)

Keeley, R. H.

1983-03-01

The scanning electron microscope equipped with an x-ray spectrometer is a versatile instrument which has many uses in the investigation of crime and preparation of scientific evidence for the courts. Major applications include microscopy and analysis of very small fragments of paint, glass and other materials which may link an individual with a scene of crime, identification of firearms residues and examination of questioned documents. Although simultaneous observation and chemical analysis of the sample is the most important feature of the instrument, other modes of operation such as cathodoluminescence spectrometry, backscattered electron imaging and direct x-ray excitation are also exploited. Marks on two bullets or cartridge cases can be compared directly by sequential scanning with a single beam or electronic linkage of two instruments. Particles of primer residue deposited on the skin and clothing when a gun is fired can be collected on adhesive tape and identified by their morphology and elemental composition. It is also possible to differentiate between the primer residues of different types of ammunition. Bullets may be identified from the small fragments left behind as they pass through the body tissues. In the examination of questioned documents the scanning electron microscope is used to establish the order in which two intersecting ink lines were written and to detect traces of chemical markers added to the security inks on official documents.

Ultrastructural morphology and localisation of cisplatin-induced platinum-DNA adducts in a cisplatin-sensitive and -resistant human small cell lung cancer cell line using electron microscopy

NARCIS (Netherlands)

Meijer, C; van Luyn, MJA; Nienhuis, EF; Blom, N; Mulder, NH; de Vries, EGE

2001-01-01

Ultrastructural morphology (transmission electron microscopy) and localisation of cisplatin-induced platinum (Pt)-DNA adducts (immunoelectron microscopy) were analysed in the human small cell lung cancer cell line GLC(4) and its 40-fold in vitro acquired cisplatin-resistant subline GLC(4)-CDDP,

Sample Preparation Methodologies for In Situ Liquid and Gaseous Cell Analytical Transmission Electron Microscopy of Electropolished Specimens.

Science.gov (United States)

Zhong, Xiang Li; Schilling, Sibylle; Zaluzec, Nestor J; Burke, M Grace

2016-12-01

In recent years, an increasing number of studies utilizing in situ liquid and/or gaseous cell scanning/transmission electron microscopy (S/TEM) have been reported. Because of the difficulty in the preparation of suitable specimens, these environmental S/TEM studies have been generally limited to studies of nanoscale structured materials such as nanoparticles, nanowires, or sputtered thin films. In this paper, we present two methodologies which have been developed to facilitate the preparation of electron-transparent samples from conventional bulk metals and alloys for in situ liquid/gaseous cell S/TEM experiments. These methods take advantage of combining sequential electrochemical jet polishing followed by focused ion beam extraction techniques to create large electron-transparent areas for site-specific observation. As an example, we illustrate the application of this methodology for the preparation of in situ specimens from a cold-rolled Type 304 austenitic stainless steel sample, which was subsequently examined in both 1 atm of air as well as fully immersed in a H2O environment in the S/TEM followed by hyperspectral imaging. These preparation techniques can be successfully applied as a general procedure for a wide range of metals and alloys, and are suitable for a variety of in situ analytical S/TEM studies in both aqueous and gaseous environments.

Bremsstrahlung background and quantitation of thin biological samples

International Nuclear Information System (INIS)

Khan, K.M.

1991-02-01

An inherent feature of all electron-excited X-ray spectra is the presence of a background upon which the characteristic peaks of interest are superimposed. To extract the x-ray intensity of the characteristics lines of interest, it is necessary to subtract this background, which may be due to both specimen generated Bremsstrahlung and extraneous sources, from a measured x-ray spectrum. Some conventional methods of background subtraction will be briefly reviewed. It has been seen that these conventional methods do not give sufficiently accurate results in biological analysis where the peaks of interest are not well-separated and most of the peaks lie in the region where the background is appreciably curved. An alternative approach of background subtraction for such samples is investigated which involves modelling the background using the currently available knowledge of x-ray physics and energy dispersive detectors. This method is particularly suitable for biological samples as well as other samples having an organic matrix. 6 figs. (author)

Contribution of the Electron Scattering Process to the Broad Hα Wings

Directory of Open Access Journals (Sweden)

Sekeráš M.

2012-06-01

Full Text Available We modeled the extended wings of the OVI 1032, 1038 Å resonance lines and He II 1640 Å emission line in the spectra of Z And, AG Dra and V1016 Cyg by the electron scattering process. By this way we determined the electron temperature and the electron optical depth of the layer of electrons, through which the line photons are transferred in the direction of the observer. We derived an empirical relationship between the emission measure of the symbiotic nebula and the electron optical depth. This relationship allows us to distinguish the flux contribution in the broad Hα wings, which is due to the electron scattering and that produced by the Hα transition in the moving hydrogen plasma. For example, subtracting the electron scattering contribution from the Hα line profile leads to a reduction in the mass-loss rate by approximately 15 %.

Determination of total and inorganic mercury in fish samples with on-line oxidation coupled to atomic fluorescence spectrometry

International Nuclear Information System (INIS)

Shao Lijun; Gan Wuer; Su Qingde

2006-01-01

An atomic fluorescence spectrometry system for determination of total and inorganic mercury with electromagnetic induction-assisted heating on-line oxidation has been developed. Potassium peroxodisulphate was used as the oxidizing agent to decompose organomercury compounds. Depending on the temperature selected, inorganic or total mercury could be determined with the same manifold. Special accent was put on the study of the parameters influencing the on-line digestion efficiency. The tolerance to the interference of coexisting ions was carefully examined in this system. Under optimal conditions, the detection limits (3σ) were evaluated to be 2.9 ng l -1 for inorganic mercury and 2.6 ng l -1 for total mercury, respectively. The relative standard deviations for 10 replicate determinations of 1.0 μg l -1 Hg were 2.4 and 3.2% for inorganic mercury and total mercury, respectively. The proposed method was successfully applied to the determination of total and inorganic mercury in fish samples

Nanosilver conductive lines made by spray coating and aerosol jet printing technique

Science.gov (United States)

Krzeminski, Jakub; Wroblewski, Grzegorz; Dybowska-Sarapuk, Lucja; Lepak, Sandra; Jakubowska, Malgorzata

2017-08-01

Printing electronics even though the printing techniques are known for a long time, are gaining in importance. The possibility of making the electronic circuits on flexible, big-area substrates with efficient and cheap technology make it attractive for the electronic industry. Spray coating, as a one of printing methods, additionally provide the chance to print on the non-flat, complicated shaped substrates. Despite the spray coating is mostly used to print a big pads, it is reachable to spray the separate conductive lines both as a quickly-produced prototype and as a fully manufactured circuit. Our work presents the directly printed lines with spray coating technique. For the printing process self-made ink was used. We tested three different approaches to line formation and compare them in the terms of line edge, resistivity and thickness. Line profiles provide the information about the roughness and the line size. In the end we showed the aerosol jet printed meander to give an overview of this similar to spray coating but more sophisticated technique.

First corrections to hyperfine splitting and the Lamb shift induced by diagrams with two external photons and second-order radiative insertions in the electron line

International Nuclear Information System (INIS)

Eides, M.I.; Karshenboim, S.G.; Shelyuto, V.A.

1994-01-01

Contributions to hyperfine splitting (HFS) and to the Lamb shift on the order of α 2 (Zα) 5 induced by graphs with two radiative photons inserted into the electron line are considered. It is shown that this gauge-invariant set of diagrams, which give corrections of the considered order, consists of nineteen topologically different diagrams. Contributions to both HFS and the Lamb shift induced by graphs containing the one-loop electron self-energy as a subgraph and by the graph containing two one-loop vertices are obtained. 15 refs., 3 figs

THEMIS Observations of the Magnetopause Electron Diffusion Region: Large Amplitude Waves and Heated Electrons

Science.gov (United States)

Tang, Xiangwei; Cattell, Cynthia; Dombeck, John; Dai, Lei; Wilson, Lynn B. III; Breneman, Aaron; Hupack, Adam

2013-01-01

We present the first observations of large amplitude waves in a well-defined electron diffusion region based on the criteria described by Scudder et al at the subsolar magnetopause using data from one Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellite. These waves identified as whistler mode waves, electrostatic solitary waves, lower hybrid waves, and electrostatic electron cyclotron waves, are observed in the same 12 s waveform capture and in association with signatures of active magnetic reconnection. The large amplitude waves in the electron diffusion region are coincident with abrupt increases in electron parallel temperature suggesting strong wave heating. The whistler mode waves, which are at the electron scale and which enable us to probe electron dynamics in the diffusion region were analyzed in detail. The energetic electrons (approx. 30 keV) within the electron diffusion region have anisotropic distributions with T(sub e(right angle))/T(sub e(parallel)) > 1 that may provide the free energy for the whistler mode waves. The energetic anisotropic electrons may be produced during the reconnection process. The whistler mode waves propagate away from the center of the "X-line" along magnetic field lines, suggesting that the electron diffusion region is a possible source region of the whistler mode waves.

Enhancement of spin polarization induced by Coulomb on-site repulsion between localized pz electrons in graphene embedded with line defects.

Science.gov (United States)

Ren, Ji-Chang; Wang, Zhigang; Zhang, Rui-Qin; Ding, Zejun; Van Hove, Michel A

2015-11-11

It is well known that the effect of Coulomb on-site repulsion can significantly alter the physical properties of the systems that contain localized d and/or f electrons. However, little attention has been paid to the Coulomb on-site repulsion between localized p electrons. In this study, we demonstrated that Coulomb on-site repulsion between localized pz electrons also plays an important role in graphene embedded with line defects. It is shown that the magnetism of the system largely depends on the choice of the effective Coulomb on-site parameter Ueff. Ueff at the edges of the defect enhances the exchange splitting, which increases the magnetic moment and stabilizes a ferromagnetic state of the system. In contrast, Ueff at the center of the defect weakens the spin polarization of the system. The behavior of the magnetism is explained with the Stoner criterion and the charge accumulation at the edges of the defect. Based on the linear response approach, we estimate reasonable values of Ueff to be 2.55 eV (2.3 eV) at the center (edges) of the defects. More importantly, using a DFT+U+J method, we find that exchange interactions between localized p electrons also play an important role in the spin polarization of the system. These results imply that Coulomb on-site repulsion is necessary to describe the strong interaction between localized pz electrons of carbon related materials.

Zero-phonon line and fine structure of the yellow luminescence band in GaN

Science.gov (United States)

Reshchikov, M. A.; McNamara, J. D.; Zhang, F.; Monavarian, M.; Usikov, A.; Helava, H.; Makarov, Yu.; Morkoç, H.

2016-07-01

The yellow luminescence band was studied in undoped and Si-doped GaN samples by steady-state and time-resolved photoluminescence. At low temperature (18 K), the zero-phonon line (ZPL) for the yellow band is observed at 2.57 eV and attributed to electron transitions from a shallow donor to a deep-level defect. At higher temperatures, the ZPL at 2.59 eV emerges, which is attributed to electron transitions from the conduction band to the same defect. In addition to the ZPL, a set of phonon replicas is observed, which is caused by the emission of phonons with energies of 39.5 meV and 91.5 meV. The defect is called the YL1 center. The possible identity of the YL1 center is discussed. The results indicate that the same defect is responsible for the strong YL1 band in undoped and Si-doped GaN samples.

Electronic module for control of sample feeding device of spectrometers of X-ray fluorescent analysis of CRV type

International Nuclear Information System (INIS)

Petrov, V.A.; Fursov, A.V.

2002-01-01

The scheme of electronic module for sample feeding device control for the CRV type X-ray fluorescence analysis spectrometers is considered. This module provides realization of next functions: sample change operations and installation in starting position; signaling and defense at emergency cases; indication of any sample amount in the spectrometer chamber; testing function at tuning and testing of modules. All these principal functions are entrusted with microcontroller. Programming of the microcontroller is putting into effect by algorithm of the whole sample feeding device. In the capacity of microcontroller the single crystalline processor PICI16C54 and stepping motor of NV-306-V2202 model have been used

Electron paramagnetic resonance (EPR) in characterization of rocks and minerals

Energy Technology Data Exchange (ETDEWEB)

Valezi, D.F.; Mauro, E. di [Universidade Estadual de Londrina (UEL), PR (Brazil). Centro de Ciencias Exatas. Lab. de Fluorescencia e Ressonaancia Paramagnetica Eletronica (LAFLURPE); Zaia, D.A.M.; Carneiro, C.E.A. [Universidade Estadual de Londrina (UEL), PR (Brazil). Centro de Ciencias Exatas. Dept. de Quimica; Costa, A.C.S. da [Universidade Estadual de Maringa (UEM), PR (Brazil). Centro de Ciencias Agrarias. Dept. de Agronomia

2011-07-01

Full text. his work is based on the study of several stones and minerals from the Parana state, Brazil. They were analyzed by the Electron Paramagnetic Resonance (EPR) technique. The measurements were made on a spectrometer JEOL (JES-PE-3X), operating on X-band and at room temperature, with the exception of the mineral Goethite, which was measured with temperature variation. In all the samples were determined spectroscopic factors (or g factor) and line widths of paramagnetic species. A great number of the samples showed in their spectra, the presence of iron complexes. Phyllite and shale showed a resonance signal with approximately g = 2, and line width with about 1000 Gauss, which indicates the presence of the hematite mineral hematite in these rocks. Shale and coal samples showed the presence of free radical, it was identified as a very intense signal, centered at about g = 2.003. Phyllite sample showed in its spectra a resonance signal between the third and fourth line of the g marker (Mg O:Mn{sup 2+}) used in the measurements, and also a signal at g = 4.3, these characteristics may indicate the presence of Kaolinite in the sample. Limestone showed a signal with line width of about 600 Gauss, centered around g = 2, this signal is probably due to a mixture of ferrihydrite and some other compound, besides the presence of manganese, displaying a spectra with its six peculiar lines, due to hyperfine splitting. The two different types of limestone presented a overlap of two distinct spectra lines for the manganese, in the first limestone sample, rich in calcite, the existence of these different spectra is a result of the manganese substitution in a single site with different orientations of the calcite; the other limestone sample, this one abundant in dolomite, the existence of these different spectra is the result of the manganese substitution in different dolomite sites, taking the place of calcium and or of the magnesium. Now, we are focusing our research in the

Applying TPM on Production Line of Huanwei

Directory of Open Access Journals (Sweden)

Zhai Yunkai

2017-01-01

The study based on the study and analysis of the TPM theory, based on my practice in the SMT2 production line of Victoria Electronics of Huanwei. Then it studied the promotion and implementation steps of TPM on SMT2 line. And it also introduced the improvement instance of SMT2 line. By contrasting the utilization of equipment on SMT2 line before and after the comprehensive of TPM, the necessity of implementing TPM is derived. For how to apply TPM on the production lines, and how to improve equipment comprehensive utilization, finish the order on time, provide high quality products to our customers, these are the main part of production line equipment management work. This article provides the reference for how to promote TPM on other production lines.

Interpretation of the [ClIII] Lines in Gaseous Nebulae.

Science.gov (United States)

Aller, L H; Czyzak, S J; Walker, M F; Krueger, T K

1970-05-01

The intensity ratio of the green lambdalambda5517 and 5537 lines of [ClIII] serves as an indicatrix of the electron density in many gaseous nebulae whose spectra can be observed with an image converter. Quantitative interpretation of the line ratio requires accurate values of the collisional strengths and transition probabilities. With improved values of these parameters we have revised electron densities for a number of nebulae; the results seem to be in good accord with those derived from other criteria.

The Fourth Workshop on Lineshape Code Comparison: Line Merging

Directory of Open Access Journals (Sweden)

Spiros Alexiou

2018-03-01

Full Text Available For a given set of plasma parameters, along a single series (Lyman, Balmer, etc. the lines with higher principal quantum number (n lines get progressively wider, closer to each other, and start merging for a certain critical n. In the present work, four different codes (with further options are used to calculate the entire Balmer series for moderate and high electron densities. Particular attention is paid to the relevant physics, such as the cutoff criteria, strong and penetrating electron collisions.

Three-dimensional reconstruction of highly complex microscopic samples using scanning electron microscopy and optical flow estimation.

Directory of Open Access Journals (Sweden)

Ahmadreza Baghaie

Full Text Available Scanning Electron Microscope (SEM as one of the major research and industrial equipment for imaging of micro-scale samples and surfaces has gained extensive attention from its emerge. However, the acquired micrographs still remain two-dimensional (2D. In the current work a novel and highly accurate approach is proposed to recover the hidden third-dimension by use of multi-view image acquisition of the microscopic samples combined with pre/post-processing steps including sparse feature-based stereo rectification, nonlocal-based optical flow estimation for dense matching and finally depth estimation. Employing the proposed approach, three-dimensional (3D reconstructions of highly complex microscopic samples were achieved to facilitate the interpretation of topology and geometry of surface/shape attributes of the samples. As a byproduct of the proposed approach, high-definition 3D printed models of the samples can be generated as a tangible means of physical understanding. Extensive comparisons with the state-of-the-art reveal the strength and superiority of the proposed method in uncovering the details of the highly complex microscopic samples.

Split-illumination electron holography

Energy Technology Data Exchange (ETDEWEB)

Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Inada, Yoshikatsu [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Matsuda, Tsuyoshi [Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Taniyama, Akira [Corporate Research and Development Laboratories, Sumitomo Metal Industries, Ltd., Amagasaki, Hyogo 660-0891 (Japan); Shindo, Daisuke [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Sendai 980-8577 (Japan); Tonomura, Akira [Advanced Science Institute, RIKEN, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Okinawa Institute of Science and Technology, Graduate University, Onna-son, Okinawa 904-0495 (Japan); Central Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-0395 (Japan)

2012-07-23

We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

Split-illumination electron holography

International Nuclear Information System (INIS)

Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon; Inada, Yoshikatsu; Matsuda, Tsuyoshi; Taniyama, Akira; Shindo, Daisuke; Tonomura, Akira

2012-01-01

We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

On the influence of the finite thickness of sources on the internal conversion lines observed in beta spectrometer

International Nuclear Information System (INIS)

Pecequilo, B.R.S.

1976-01-01

Electron lines are simulated by a Monte Carlo method in a digital computer in order to obtain an analytical formula to calculate the energy and the relative intensity of electron conversion lines when observed by beta spectrometry. The electrons come from the own thickness of the source. Computer program that simulate these lines is presented. In order to test the method, a direct comparison of the K-line of Hg-198 with the same line as simulated by the computer, is done [pt

Solid-phase extraction of polar pesticides from environmental water samples on graphitized carbon and Empore-activated carbon disks and on-line coupling to octadecyl-bonded silica analytical columns.

Science.gov (United States)

Slobodník, J; Oztezkizan, O; Lingeman, H; Brinkman, U A

1996-10-25

The suitability of Empore-activated carbon disks (EACD), Envi-Carb graphitized carbon black (GCB) and CPP-50 graphitized carbon for the trace enrichment of polar pesticides from water samples was studied by means of off-line and on-line solid-phase extraction (SPE). In the off-line procedure, 0.5-2 l samples spiked with a test mixture of oxamyl, methomyl and aldicarb sulfoxide were enriched on EnviCarb SPE cartridges or 47 mm diameter EACD and eluted with dichloromethane-methanol. After evaporation, a sample was injected onto a C18-bonded silica column and analysed by liquid chromatography with ultraviolet (LC-UV) detection. EACD performed better than EnviCarb cartridges in terms of breakthrough volumes (> 2 l for all test analytes), reproducibility (R.S.D. of recoveries, 4-8%, n = 3) and sampling speed (100 ml/min); detection limits in drinking water were 0.05-0.16 microgram/l. In the on-line experiments, 4.6 mm diameter pieces cut from original EACD and stacked onto each other in a 9 mm long precolumn, and EnviCarb and CPP-50 packed in 10 x 2.0 mm I.D. precolumn, were tested, and 50-200 ml spiked water samples were preconcentrated. Because of the peak broadening caused by the strong sorption of the analytes on carbon, the carbon-packed precolumns were eluted by a separate stream of 0.1 ml/min acetonitrile which was mixed with the gradient LC eluent in front of the C18 analytical column. The final on-line procedure was also applied for the less polar propoxur, carbaryl and methiocarb. EnviCarb could not be used due to its poor pressure resistance. CPP-50 provided less peak broadening than EACD: peak widths were 0.1-0.3 min and R.S.D. of peak heights 4-14% (n = 3). In terms of analyte trapping efficiency on-line SPE-LC-UV with a CPP-50 precolumn also showed better performance than when Bondesil C18/OH or polymeric PLRP-S was used, but chromatographic resolution was similar. With the CPP-50-based system, detection limits of the test compounds were 0.05-1 microgram

The [NeIV] Lines in High Excitation Gaseous Nebulae.

Science.gov (United States)

Aller, L H

1970-04-01

The "forbidden" lines of three times ionized neon are among the most precious indicators of electron temperature and excitation. They are also predicted to be among the strongest lines observed in the far ultraviolet spectra of high excitation nebulae.

Stark shift measurements of Xe II and Xe III spectral lines

International Nuclear Information System (INIS)

Cirisan, M; Pelaez, R J; Djurovic, S; Aparicio, J A; Mar, S

2007-01-01

Stark shift measurements of singly and doubly ionized Xe spectral lines are presented in this paper. Shifts of 110 Xe II lines and 42 Xe III lines are reported, including a significant number of new results. A low-pressure-pulsed arc with 95% of He and 5% of Xe was used as a plasma source. All measurements were performed under the following plasma conditions: electron density (0.2-1.4) x 10 23 m -3 and electron temperature 18 000-23 000 K. The measured Stark shifts are compared with other experimental and theoretical data

Documentary Realism, Sampling Theory and Peircean Semiotics: electronic audiovisual signs (analog or digital as indexes of reality

Directory of Open Access Journals (Sweden)

Hélio Godoy

2007-07-01

Full Text Available This paper addresses Documentary Realism, focusing on thephysical phenomena of transduction that take place in analog and digital audiovisual systems, herein analyzed in the light of the Sampling Theory, within the framework of Shannon and Weaver’s Information Theory. Transduction is a process by which one type of energy is transformed into another, or by which information is transcodified. Within the scope of Documentary Realism, it cannotbe claimed that electronic audiovisual signs, because of their technical digital features lead to a rupture with reality. Rather, the digital documentary, based on electronic digital cinematography, is still an index of reality.

Characteristics of recycled and electron beam irradiated high density polyethylene samples

International Nuclear Information System (INIS)

Cardoso, Jessica R.; Gabriel, Leandro; Geraldo, Aurea B.C.; Moura, Eduardo

2015-01-01

Polymers modification by irradiation is a well-known process that allows degradation and cross-linking in concurrent events; this last is expected when an increase of mechanical properties is required. Actually, the interest of recycling and reuse of polymeric material is linked to the increase of plastics ending up in waste streams. Therefore, these both irradiation and recycling process may be conducted to allow a new use to this material that would be discarded by an improvement of its mechanical properties. In this work, the High Density Polyethylene (HDPE) matrix has been recycled five times from original substrate. The electron beam irradiation process was applied from 50 kGy to 200 kGy in both original and recycled samples; in this way, mechanical properties and thermal characteristics were evaluated. The results of applied process and material characterization are discussed. (author)

Characteristics of recycled and electron beam irradiated high density polyethylene samples

Energy Technology Data Exchange (ETDEWEB)

Cardoso, Jessica R.; Gabriel, Leandro; Geraldo, Aurea B.C.; Moura, Eduardo, E-mail: jrcardoso@ipen.br, E-mail: lgabriell@gmail.com, E-mail: ageraldo@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2015-07-01

Polymers modification by irradiation is a well-known process that allows degradation and cross-linking in concurrent events; this last is expected when an increase of mechanical properties is required. Actually, the interest of recycling and reuse of polymeric material is linked to the increase of plastics ending up in waste streams. Therefore, these both irradiation and recycling process may be conducted to allow a new use to this material that would be discarded by an improvement of its mechanical properties. In this work, the High Density Polyethylene (HDPE) matrix has been recycled five times from original substrate. The electron beam irradiation process was applied from 50 kGy to 200 kGy in both original and recycled samples; in this way, mechanical properties and thermal characteristics were evaluated. The results of applied process and material characterization are discussed. (author)

Dynamic Model for the Z Accelerator Vacuum Section Based on Transmission Line Code%Dynamic Model for the Z Accelerator Vacuum Section Based on Transmission Line Code

Institute of Scientific and Technical Information of China (English)

呼义翔; 雷天时; 吴撼宇; 郭宁; 韩娟娟; 邱爱慈; 王亮平; 黄涛; 丛培天; 张信军; 李岩; 曾正中; 孙铁平

2011-01-01

The transmission-line-circuit model of the Z accelerator, developed originally by W. A. STYGAR, P. A. CORCORAN, et al., is revised. The revised model uses different calculations for the electron loss and flow impedance in the magnetically insulated transmission line system of the Z accelerator before and after magnetic insulation is established. By including electron pressure and zero electric field at the cathode, a closed set of equations is obtained at each time step, and dynamic shunt resistance （used to represent any electron loss to the anode） and flow impedance are solved, which have been incorporated into the transmission line code for simulations of the vacuum section in the Z accelerator. Finally, the results are discussed in comparison with earlier findings to show the effectiveness and limitations of the model.

Electron spectroscopy of crystals

CERN Document Server

Nemoshkalenko, V V

1979-01-01

This book is conceived as a monograph, and represents an up-to-date collection of information concerning the use of the method of X-ray photoelectron spec­ troscopy in the study of the electron structure of crystals, as well as a personal interpretation of the subject by the authors. In a natural way, the book starts in Chapter 1 with a recapitulation of the fundamentals of the method, basic relations, principles of operation, and a com­ parative presentation of the characteristics and performances of the most com­ monly used ESCA instruments (from the classical ones-Varian, McPherson, Hewlett Packard, and IEEE-up to the latest model developed by Professor Siegbahn in Uppsala), and continues with a discussion of some of the difficult problems the experimentalist must face such as calibration of spectra, prepara­ tion of samples, and evaluation of the escape depth of electrons. The second chapter is devoted to the theory of photoemission from crystal­ line solids. A discussion of the methods of Hartree-Fo...

Derivative spectrum chromatographic method for the determination of trimethoprim in honey samples using an on-line solid-phase extraction technique.

Science.gov (United States)