Journal articles: 'Dynamická SIMS'

1

Linton, Richard W. "Direct Imaging of Trace Elements, Isotopes, and Molecules Using Mass Spectrometry." Microscopy and Microanalysis 4, S2 (July 1998): 124–25. http://dx.doi.org/10.1017/s1431927600020742.

Full text

Abstract:

Secondary ion mass spectrometry (SIMS) is based upon the energetic ion bombardment of surfaces resulting in in the emission of sputtered particles, including both atomic and molecular ions. The use of mass spectrometric detection provides a highly versatile and sensitive tool for surface and thin film microanalysis. The scope of the technique includes a diversity of analysis modes including:1.Elemental Depth Profiling (dynamic SIMS),2.Laterally Resolved Imaging (ion microprobe or ion microscope analysis),3.Image Depth Profiling (combination of modes 1 and 2 providing 3-D images),4.Molecular Monolayer Analysis and Imaging (static SIMS),5.Sputtered Neutral Mass Spectrometry (post-ionization).Much of the early work in dynamic SIMS centered on depth profiling and imaging techniques, with an emphasis on applications to electronic materials. SIMS has made extensive contributions to semiconductor materials science since the 1960's, including the development of new devices and processes, and in failure analysis.

APA, Harvard, Vancouver, ISO, and other styles

2

Linton, Richard W. "Secondary ion mass spectroscopy in the biological and materials sciences." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 498–99. http://dx.doi.org/10.1017/s0424820100148320.

Full text

Abstract:

Secondary ion mass spectrometry (SIMS) is based upon energetic ion bombardment of surfaces resulting in in the emission of sputtered particles, including both atomic and molecular ions. The use of mass spectrometric detection provides a highly versatile and sensitive tool for surface and thin film chemical analysis. In recent years, the scope of the technique has broadened to include a variety of analysis modes including:1.Elemental Depth Profiling (dynamic SIMS),2.Laterally Resolved Imaging (ion microprobe or ion microscope analysis),3.Image Depth Profiling (combination of modes 1 and 2 providing 3-D images),4.Molecular Monolayer Analysis (static SIMS),5.Sputtered Neutral Mass Spectrometry (post-ionization).Much of the early work in dynamic SIMS centered on the development of depth profiling and imaging techniques, with an emphasis on applications to electronic materials. SIMS has made extensive contributions to semiconductor materials science since the 1960's, including the development of new devices and processes, and in failure analysis.

APA, Harvard, Vancouver, ISO, and other styles

3

Singh, Saurabh Kumar, Tulika Gupta, Maheswaran Shanmugam, and Gopalan Rajaraman. "Unprecedented magnetic relaxation via the fourth excited state in low-coordinate lanthanide single-ion magnets: a theoretical perspective." Chem. Commun. 50, no. 98 (2014): 15513–16. http://dx.doi.org/10.1039/c4cc05522e.

Full text

Abstract:

How to enhance the barrier heights in lanthanide based SIMs? Using ab initio calculations, we have explored the role of symmetry and the coordination number on the magnetization dynamics of four three-coordinate Ln(iii) SIMs.

APA, Harvard, Vancouver, ISO, and other styles

4

Lakens, Daniël, and Kirsten I. Ruys. "The dynamic interaction of conceptual and embodied knowledge." Behavioral and Brain Sciences 33, no. 6 (December 2010): 449–50. http://dx.doi.org/10.1017/s0140525x10001329.

Full text

Abstract:

AbstractWe propose the SIMS model can be strengthened by detailing the dynamic interaction between sensorimotor activation and contextual conceptual information. Rapidly activated evaluations and contextual knowledge can guide and constrain embodied simulations. In addition, we stress the potential importance of extending the SIMS model to dynamic social interactions that go beyond the passive observer.

APA, Harvard, Vancouver, ISO, and other styles

5

Fahey, A. J. "Isotopic Measurements of Inorganic Material by Time-Of-Flight SIMS." Microscopy and Microanalysis 4, S2 (July 1998): 412–13. http://dx.doi.org/10.1017/s1431927600022182.

Full text

Abstract:

Isotopic measurements via Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) have generally not been considered as practical because of the low duty cycle at which ToF-SIMS instruments operate and the corresponding low data rate. The recent discovery of pre-solar material in meteorites has shown that large variations in isotopic ratios (several orders of magnitude for some elements) exist in small (∼1 μm), refractory meteoritic grains. These grains are ideal candidates for ToF-SIMS, which consumes little sample material, compared to dynamic, magneticsector SIMS. ToF-SIMS also allows for parallel detection of all species present in the sample; thus, multiple isotopic systems can be studied in one measurement. As a prerequisite to studying the isotopic composition of meteoritic materials, preliminary determinations of ratios for a number of elements have been made on materials of known isotopic composition. This allows us to investigate problems that may be unique to ToF-SIMS for the measurement of isotopic ratios.

APA, Harvard, Vancouver, ISO, and other styles

6

Lodding, A. "SIMS of Biomineralized Tissues: Present Trends and Potentials." Advances in Dental Research 11, no. 4 (November 1997): 364–79. http://dx.doi.org/10.1177/08959374970110040101.

Full text

Abstract:

The technique of dynamic secondary ion mass spectrometry (SIMS) has, during the 1980s, become a firmly established tool in the microanalytical and microstructural characterization of dental hard tissues. SIMS has proved to be outstandingly suited for charting the distributions of most elements, even at extremely low concentrations, in tooth and bone materials. In-depth concentration profiles as well as surface distribution maps of elements have been recorded with excellent (sub-micron) morphologic resolution. In spite of documented success, only relatively few teams, in a handful of countries, are presently engaged, to any significant extent, in conducting tooth or bone research by the application of SIMS. For dental-medical-surgical laboratories, a partial reason for non-communication is a lack of information about SIMS and its particular assets. Another reason may be connected with an essentially groundless reputation, among non-specialists, of SIMS being an exclusive and expensive technique. Among SIMS laboratories, on the other hand, the inertia in tackling biomineralization is partly due to some particular artifacts of analysis, hitherto not generally known and controlled. The present paper briefly sketches the chief principles of modem SIMS, emphasizing factors of special relevance in the characterization of biomineralized tissues. Examples of recent applications are provided. Present procedures and their limitations are discussed, especially with regard to elemental quantification and imaging. Suggestions for relatively simple modifications to existing routines are offered with the aim of enhancing the ease and availability of SIMS in odontological and surgical research.

APA, Harvard, Vancouver, ISO, and other styles

7

Alzbutas, R., and V. Janilionis. "THE SIMULATION OF DYNAMIC SYSTEMS USING COMBINED MODELLING." Mathematical Modelling and Analysis 5, no. 1 (December 15, 2000): 7–17. http://dx.doi.org/10.3846/13926292.2000.9637123.

Full text

Abstract:

The new approach to the problems of dynamic systems simulation is proposed. The analytical and imitation modelling of non‐linear complex dynamic systems which comprise simulation of continuous and discrete processes with constant and variable parameters, are investigated. The aggregate mathematical modelling scheme [1] and the method of control sequences for discrete systems specification and simulation are used as well as the dynamic mathematical modelling scheme for continuous process formalization and modelling. According to them the investigated systems are presented as the set of interacting piecewise linear aggregates, which can include processes described with differential equations. The above mentioned approach is used in developing software for the construction and research of the models. The modelling of the dynamic systems’ control is also analyzed and developed software for the dynamic systems’ simulation is presented. It is related to the proposed combined modelling methodology. The developed dynamical simulation system ADPRO (Automatic Differentiation PROgram) extends applicability of the system SIMAS (SIMulation of the Aggregate Systems) [2] with dynamical simulation means realized with APL2 (A Programming Language 2) and based on automatic differentiation [3]. The created model of service process and its control can be used as a base for other models of wide class complex dynamics’ systems [4], the parts of which are described with differential equations.

APA, Harvard, Vancouver, ISO, and other styles

8

Martinez-Limia, Alberto, Peter Pichler, Christian Steen, Silke Paul, and Wilfried Lerch. "Modeling of the Diffusion and Activation of Arsenic in Silicon Including Clustering and Precipitation." Solid State Phenomena 131-133 (October 2007): 277–82. http://dx.doi.org/10.4028/www.scientific.net/ssp.131-133.277.

Full text

Abstract:

We have developed a diffusion and activation model for implanted arsenic in silicon. The model includes the dynamic formation of arsenic-vacancy complexes (As4V) as well as the precipitation of a SiAs phase. The latter is mandatory to correctly describe concentrations above solid solubility while the former are needed to describe the reduced electrical activity as well as the generation of self-interstitials during deactivation. In addition, the activation state after solid-phase epitaxy and the segregation at the interface to SiO2 are taken into account. After implementation using the Alagator language in the latest version of the Sentaurus Process Simulator of Synopsys, the parameters of the model were optimized using reported series of diffusion coefficients for temperatures between 700 °C and 1200 °C, and using several SIMS profiles covering annealing processes from spike to very long times with temperatures between 700 °C and 1050 °C and a wide distribution of implantation energies and doses. The model was validated using data from flash-assisted RTP and spike annealing of ultra-low energy arsenic implants.

APA, Harvard, Vancouver, ISO, and other styles

9

Lee, J. J., J. L. Hunter, W. J. Lin, and R. W. Linton. "Three-Dimensional Display of Secondary Ion Images." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 2 (August 12, 1990): 344–45. http://dx.doi.org/10.1017/s0424820100135320.

Full text

Abstract:

Since the sample surface region is continuously sputtered in dynamic secondary ion mass spectrometry (SIMS), three dimensional (3D) chemical maps can be obtained by acquiring a series of two dimensional (2D) images. Owing to the limitations of the ion beam sputtering technique, SIMS analysis artifacts resulting from factors such as surface roughness, matrix effects, and atomic mixing are present in the 3D volume data. One potential advantage of using 3D display is to provide visual feedback regarding the elimination of artifacts by utilizing correction algorithms as well as correlative information obtained from other surface imaging techniques. In this paper, SIMS 3D maps are displayed by a volume rendering technique in which more information is retained in the image processing steps.Various 3D display methods have been proposed for SIMS and other microscopic imaging techniques. Some of the previous methods can not display the complete 3D spatial distribution of mass-selected ion intensities.

APA, Harvard, Vancouver, ISO, and other styles

10

Frickel, Scott, and Neil Gross. "A General Theory of Scientific/Intellectual Movements." American Sociological Review 70, no. 2 (April 2005): 204–32. http://dx.doi.org/10.1177/000312240507000202.

Full text

Abstract:

The histories of all modern scientific and intellectual fields are marked by dynamism. Yet, despite a welter of case study data, sociologists of ideas have been slow to develop general theories for explaining why and how disciplines, subfields, theory groups, bandwagons, actor networks, and other kindred formations arise to alter the intellectual landscape. To fill this lacuna, this article presents a general theory of scientific/intellectual movements (SIMs). The theory synthesizes work in the sociology of ideas, social studies of science, and the literature on social movements to explain the dynamics of SIMs, which the authors take to be central mechanisms for change in the world of knowledge and ideas. Illustrating their arguments with a diverse sampling of positive and negative cases, they define SIMs, identify a set of theoretical presuppositions, and offer four general propositions for explaining the social conditions under which SIMs are most likely to emerge, gain prestige, and achieve some level of institutional stability.

APA, Harvard, Vancouver, ISO, and other styles

11

Pang, Wei Kong, It Meng Low, and J. V. Hanna. "Detection of Amorphous Silica in Air-Oxidized Ti₃SiC₂ at 500–1000°C by NMR and SIMS." Key Engineering Materials 434-435 (March 2010): 169–72. http://dx.doi.org/10.4028/www.scientific.net/kem.434-435.169.

Full text

Abstract:

The use of secondary-ion mass spectrometry (SIMS), nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM) to detect the existence of amorphous silica in Ti3SiC2 oxidised at 500–1000°C is described. The formation of an amorphous SiO2 layer and its growth in thickness with temperature was monitored using dynamic SIMS. Results of NMR and TEM verify for the first time the direct evidence of amorphous silica formation during the oxidation of Ti3SiC2 at 1000°C.

APA, Harvard, Vancouver, ISO, and other styles

12

Wu, Yuewei, Danian Tian, Jesús Ferrando-Soria, Joan Cano, Lei Yin, Zhongwen Ouyang, Zhenxing Wang, Shuchang Luo, Xiangyu Liu, and Emilio Pardo. "Modulation of the magnetic anisotropy of octahedral cobalt(ii) single-ion magnets by fine-tuning the axial coordination microenvironment." Inorganic Chemistry Frontiers 6, no. 3 (2019): 848–56. http://dx.doi.org/10.1039/c8qi01373j.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Ali, Basharat, Xiao-Lei Li, Frédéric Gendron, Boris Le Guennic, and Jinkui Tang. "A new class of DyIII-SIMs associated with a guanidine-based ligand." Dalton Transactions 50, no. 15 (2021): 5146–53. http://dx.doi.org/10.1039/d1dt00260k.

Full text

Abstract:

The diverse relaxation dynamics of a series of Dy^III-based SIMs resulting from the coordinated molecules and counter anions were elucidated by structural analysis, magnetic investigations and ab initio calculations.

APA, Harvard, Vancouver, ISO, and other styles

14

Newbury, Dale E. "Ion microscope and microprobe studies of surfaces and interfaces." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 856–57. http://dx.doi.org/10.1017/s0424820100150113.

Full text

Abstract:

Secondary ion mass spectrometry (SIMS) in its spatially-resolved forms, the ion microscope and ion microprobe, offers elemental, isotopic, and molecular detection, wide dynamic intensity range spanning major to trace concentrations in the part per million (ppm) range or lower, high lateral spatial resolution in the micrometer to sub-micrometer range, shallow sampling depths to the nanometer range, and the possibility of "microanalytical tomography", the reconstruction of three-dimensional distributions. With this broad range of capabilities, SIMS has special advantages for the characterization of surfaces and interfaces that complement the measurement capabilities of other microanalysis/surface analysis techniques such as electron probe x-ray microanalysis (EPMA), analytical electron microscopy (AEM), Raman and infrared microscopy, scanning Auger electron microanalysis (SAM/AES), and spatially-resolved x-ray photoelectron spectroscopy (XPS). Examples of applications will highlight the special contributions of SIMS to surface/interface characterization studies.1. Surface studiesFigure 1 shows an example of characterization with extreme surface sensitivity. Changes in surface chemistry induced on a passivated silicon surface by scanning tunneling microscopy in air are revealed by time-of-flight secondary ion mass spectrometry (TOF-SIMS).

APA, Harvard, Vancouver, ISO, and other styles

15

Xu, Duo, Xin Hua, Shao-Chuang Liu, Hong-Wei Qiao, Hua-Gui Yang, Yi-Tao Long, and He Tian. "In situ and real-time ToF-SIMS analysis of light-induced chemical changes in perovskite CH3NH3PbI3." Chemical Communications 54, no. 43 (2018): 5434–37. http://dx.doi.org/10.1039/c8cc01606b.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Chisanga, Malama, Howbeer Muhamadali, Danielle McDougall, Yun Xu, Nicholas Lockyer, and Royston Goodacre. "Metabolism in action: stable isotope probing using vibrational spectroscopy and SIMS reveals kinetic and metabolic flux of key substrates." Analyst 146, no. 5 (2021): 1734–46. http://dx.doi.org/10.1039/d0an02319a.

Full text

Abstract:

Raman and infrared are used to measure dynamics in bacterial metabolism by employing stable isotope probing with temporal acquisition. The work is complemented by SIMS for confirmation of ¹³C incorporation into bacterial biomass.

APA, Harvard, Vancouver, ISO, and other styles

17

McMahon, G., M. W. Phaneuf, and L. Weaver. "SIMS depth profiling and direct ion imaging of a 16-megabit DRAM." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 962–63. http://dx.doi.org/10.1017/s0424820100167275.

Full text

Abstract:

The use of secondary ion mass spectrometry (SIMS) has long been established as a powerful tool forthe analysis of microelectronic devices. However, as newer fabrication technologies emerge, and device dimensions shrink, increasing demands are placed upon the SIMS analyst.The present work illustrates how the depth profiling and direct ion imaging capabilities of a Cameca ims 4f SIMS can be exploited to determine the structure and dopant chemistry of a state-of-the-art16 megabit DRAM (dynamic random access memory) device. The optical micrograph shown in Fig. 1 is an overview of a portion of the sense amplifiers located between two array blocks. In the centre of this area, p-type devices sitting in an n-well, surrounded on either side by n-type devices, all in a p-type substrate can be observed. The object of the study was to determine if a low concentration p-type implant is present below the n-type devices.

APA, Harvard, Vancouver, ISO, and other styles

18

McIntyre, N. S., D. M. Kingston, P. A. W. van der Heide, M. L. Wagter, M. B. Stanley, and A. H. Clarke. "Volumetric rendering of 3D SIMS depth profiles." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 1050–51. http://dx.doi.org/10.1017/s0424820100167718.

Full text

Abstract:

Dynamic secondary ion mass spectrometry (SIMS) can be used to uncover unique information about interfaces and whole structures which are “buried” within a solid. During a depth profile of a solid, a sequence of SIMS images is acquired for each element under study The sequence is correlated into a vertical “stack” which contains digitised three dimensional (3D) elemental distributions. Although such distributions are distorted by surface roughness, preferential sputtering and SIMS matrix effects, there is still considerable structural information contained in the volume and much potential for further information retrieval as the above-mentioned distorting effects are addressedOne of the major tools used to assess distributional information within the 3D volume has been visual rendering software. Using Sunvision software (Sun Microsystems Inc.) and a small workstation, images of the volume can be constructed which display pixels either in a “maximum value” perspective or in perspectives where the density of each phase can be adjusted to maximise structural detail.Several examples of the technique will be shown.

APA, Harvard, Vancouver, ISO, and other styles

19

Coban, Mathew A., Patrick R. Blackburn, Murray L. Whitelaw, Mieke M. van Haelst, Paldeep S. Atwal, and Thomas R. Caulfield. "Structural Models for the Dynamic Effects of Loss-of-Function Variants in the Human SIM1 Protein Transcriptional Activation Domain." Biomolecules 10, no. 9 (September 12, 2020): 1314. http://dx.doi.org/10.3390/biom10091314.

Full text

Abstract:

Single-minded homologue 1 (SIM1) is a transcription factor with numerous different physiological and developmental functions. SIM1 is a member of the class I basic helix-loop-helix-PER-ARNT-SIM (bHLH–PAS) transcription factor family, that includes several other conserved proteins, including the hypoxia-inducible factors, aryl hydrocarbon receptor, neuronal PAS proteins, and the CLOCK circadian regulator. Recent studies of HIF-a-ARNT and CLOCK-BMAL1 protein complexes have revealed the organization of their bHLH, PASA, and PASB domains and provided insight into how these heterodimeric protein complexes form; however, experimental structures for SIM1 have been lacking. Here, we describe the first full-length atomic structural model for human SIM1 with its binding partner ARNT in a heterodimeric complex and analyze several pathogenic variants utilizing state-of-the-art simulations and algorithms. Using local and global positional deviation metrics, deductions to the structural basis for the individual mutants are addressed in terms of the deleterious structural reorganizations that could alter protein function. We propose new experiments to probe these hypotheses and examine an interesting SIM1 dynamic behavior. The conformational dynamics demonstrates conformational changes on local and global regions that represent a mechanism for dysfunction in variants presented. In addition, we used our ab initio hybrid model for further prediction of variant hotspots that can be engineered to test for counter variant (restoration of wild-type function) or basic research probe.

APA, Harvard, Vancouver, ISO, and other styles

20

Kung, Camy C. H., Mandar T. Naik, Szu-Huan Wang, Hsiu-Ming Shih, Che-Chang Chang, Li-Ying Lin, Chia-Lin Chen, Che Ma, Chi-Fon Chang, and Tai-Huang Huang. "Structural analysis of poly-SUMO chain recognition by the RNF4-SIMs domain." Biochemical Journal 462, no. 1 (July 24, 2014): 53–65. http://dx.doi.org/10.1042/bj20140521.

Full text

Abstract:

Using a multi-faceted approach we unveil the dynamic nature and elucidate the molecular basis of avidity of the poly-SUMO-SIMs domain interaction. A knowledge-based HADDOCK model of the complex reveals a helical structure that serves as a framework for subsequent functional understanding.

APA, Harvard, Vancouver, ISO, and other styles

21

Linton, Richard W. "Three-dimensional compositional mapping using ion microscopy and volume-rendering techniques." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1614–15. http://dx.doi.org/10.1017/s0424820100132704.

Full text

Abstract:

Secondary ion mass spectrometry (SIMS), using ion microprobe or microscope instrumentation, couples lateral imaging and dynamic ion beam sputtering to provide 3-D compositional maps (image depth profiles). A data set acquired with an ion microscope may involve more than 100 massresolved ion images, each containing at least 64,000 pixels, with typical lateral and depth resolutions of 1 μm and 10 nm, respectively. The vast majority of prior quantitative surface analysis studies have addressed depth profiling, thin film, or overlayer measurements without the additional feature of laterally resolved imaging. The ability to create 3-D compositional maps using SIMS creates enormous challenges for quantification. In principle, each volume element requires individual calibration reflecting the combined effects of spatial resolution, sample heterogeneity, and variations in instrumental response. An overview of analytical considerations will be presented involving aspects of data acquisition, display, and processing, with a special emphasis on sector field mass spectrometers that provide high dynamic range image depth profiles.

APA, Harvard, Vancouver, ISO, and other styles

22

Li, Quan-Wen, Jun-Liang Liu, Jian-Hua Jia, Yan-Cong Chen, Jiang Liu, Long-Fei Wang, and Ming-Liang Tong. "“Half-sandwich” YbIII single-ion magnets with metallacrowns." Chemical Communications 51, no. 51 (2015): 10291–94. http://dx.doi.org/10.1039/c5cc03389f.

Full text

Abstract:

Two “half-sandwich” Yb^III-SIMs are presented bearing metallacrowns. The central ytterbium ion is coordinated by YbO₈ geometry in D_4d symmetry. The analysis of static, dynamic magnetism and emission spectrum offers an insight into the magneto-optical correlation.

APA, Harvard, Vancouver, ISO, and other styles

23

Chaumont, Nicolas, Richard Egli, and Christoph Adami. "Evolving Virtual Creatures and Catapults." Artificial Life 13, no. 2 (April 2007): 139–57. http://dx.doi.org/10.1162/artl.2007.13.2.139.

Full text

Abstract:

We present a system that can evolve the morphology and the controller of virtual walking and block-throwing creatures (catapults) using a genetic algorithm. The system is based on Sims' work, implemented as a flexible platform with an off-the-shelf dynamics engine. Experiments aimed at evolving Sims-type walkers resulted in the emergence of various realistic gaits while using fairly simple objective functions. Due to the flexibility of the system, drastically different morphologies and functions evolved with only minor modifications to the system and objective function. For example, various throwing techniques evolved when selecting for catapults that propel a block as far as possible. Among the strategies and morphologies evolved, we find the drop-kick strategy, as well as the systematic invention of the principle behind the wheel, when allowing mutations to the projectile.

APA, Harvard, Vancouver, ISO, and other styles

24

Forni, Mario, and Marco Lippi. "THE GENERALIZED DYNAMIC FACTOR MODEL: REPRESENTATION THEORY." Econometric Theory 17, no. 6 (December 2001): 1113–41. http://dx.doi.org/10.1017/s0266466601176048.

Full text

Abstract:

This paper, along with the companion paper Forni, Hallin, Lippi, and Reichlin (2000, Review of Economics and Statistics 82, 540–554), introduces a new model—the generalized dynamic factor model—for the empirical analysis of financial and macroeconomic data sets characterized by a large number of observations both cross section and over time. This model provides a generalization of the static approximate factor model of Chamberlain (1983, Econometrica 51, 1181–1304) and Chamberlain and Rothschild (1983, Econometrica 51, 1305–1324) by allowing serial correlation within and across individual processes and of the dynamic factor model of Sargent and Sims (1977, in C.A. Sims (ed.), New Methods in Business Cycle Research, pp. 45–109) and Geweke (1977, in D.J. Aigner & A.S. Goldberger (eds.), Latent Variables in Socio-Economic Models, pp. 365–383) by allowing for nonorthogonal idiosyncratic terms. Whereas the companion paper concentrates on identification and estimation, here we give a full characterization of the generalized dynamic factor model in terms of observable spectral density matrices, thus laying a firm basis for empirical implementation of the model. Moreover, the common factors are obtained as limits of linear combinations of dynamic principal components. Thus the paper reconciles two seemingly unrelated statistical constructions.

APA, Harvard, Vancouver, ISO, and other styles

25

Cabin-Flaman, Armelle, Anne-Francoise Monnier, Yannick Coffinier, Jean-Nicolas Audinot, David Gibouin, Tom Wirtz, Rabah Boukherroub, et al. "Combining combing and secondary ion mass spectrometry to study DNA on chips using 13C and 15N labeling." F1000Research 5 (June 20, 2016): 1437. http://dx.doi.org/10.12688/f1000research.8361.1.

Full text

Abstract:

Dynamic secondary ion mass spectrometry (D-SIMS) imaging of combed DNA – the combing, imaging by SIMS or CIS method – has been developed previously using a standard NanoSIMS 50 to reveal, on the 50 nm scale, individual DNA fibers labeled with different, non-radioactive isotopes in vivo and to quantify these isotopes. This makes CIS especially suitable for determining the times, places and rates of DNA synthesis as well as the detection of the fine-scale re-arrangements of DNA and of molecules associated with combed DNA fibers. Here, we show how CIS may be extended to 13C-labeling via the detection and quantification of the 13C14N- recombinant ion and the use of the 13C:12C ratio, we discuss how CIS might permit three successive labels, and we suggest ideas that might be explored using CIS.

APA, Harvard, Vancouver, ISO, and other styles

26

Strick, Reiner, Pamela L. Strissel, Konstantin Gavrilov, and Riccardo Levi-Setti. "Cation–chromatin binding as shown by ion microscopy is essential for the structural integrity of chromosomes." Journal of Cell Biology 155, no. 6 (December 10, 2001): 899–910. http://dx.doi.org/10.1083/jcb.200105026.

Full text

Abstract:

Mammalian interphase and mitotic cells were analyzed for their cation composition using a three-dimensional high resolution scanning ion microprobe. This instrument maps the distribution of bound and unbound cations by secondary ion mass spectrometry (SIMS). SIMS analysis of cryofractured interphase and mitotic cells revealed a cell cycle dynamics of Ca2+, Mg2+, Na+, and K+. Direct analytical images showed that all four, but no other cations, were detected on mitotic chromosomes. SIMS measurements of the total cation content for diploid chromosomes imply that one Ca2+ binds to every 12.5–20 nucleotides and one Mg2+ to every 20–30 nucleotides. Only Ca2+ was enriched at the chromosomal DNA axis and colocalized with topoisomerase IIα (Topo II) and scaffold protein II (ScII). Cells depleted of Ca2+ and Mg2+ showed partially decondensed chromosomes and a loss of Topo II and ScII, but not hCAP-C and histones. The Ca2+-induced inhibition of Topo II catalytic activity and direct binding of Ca2+ to Topo II by a fluorescent filter-binding assay supports a regulatory role of Ca2+ during mitosis in promoting solely the structural function of Topo II. Our study directly implicates Ca2+, Mg2+, Na+, and K+ in higher order chromosome structure through electrostatic neutralization and a functional interaction with nonhistone proteins.

APA, Harvard, Vancouver, ISO, and other styles

27

WASHIZU, Hitoshi, Seiji KAJITA, Shi-aki HYODO, Toshihide OHMORI, Hiroshi TERANISHI, and Atsushi SUZUKI. "SIM-08 DYNAMIC STRUCTURE OF BOUNDARY LUBRICATING WATER FILM ON HYDROPHILIC SURFACES USING MOLECULAR DYNAMICS SIMULATION(Simulations of Micro/Nano Scale Phenomena III,Technical Program of Oral Presentations)." Proceedings of JSME-IIP/ASME-ISPS Joint Conference on Micromechatronics for Information and Precision Equipment : IIP/ISPS joint MIPE 2009 (2009): 271–72. http://dx.doi.org/10.1299/jsmemipe.2009.271.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Odom, Robert W., and Martin L. Grossbeck. "In-depth and ion image analysis of minor and trace constituents in V–Cr–Ti alloy welds." Journal of Materials Research 11, no. 8 (August 1996): 1923–33. http://dx.doi.org/10.1557/jmr.1996.0243.

Full text

Abstract:

This paper describes the application of dynamic secondary ion mass spectrometry (SIMS) to the study of the chemistry of welds in V–Cr–Ti alloys and presents preliminary data on the distribution of minor and trace elements (H, C, N, O, P, S, and C1) in welds produced by gas tungsten arc (GTA) and electron beam techniques. The motivation for this research is to develop techniques that determine correlations between the concentration and distribution of trace elements in alloy metal welds and the physical properties of the weld. To this end, quantitative SIMS techniques were developed for N, O, and S analysis in vanadium alloy welds using an ion implantation/relative sensitivity factor methodology. The data presented in this paper demonstrate that trace compositions and distributions of selected welds correlate, at least qualitatively, with such properties as microhardness and tensile elongation. These data support continuing these investigations to develop microanalysis methods that quantitatively correlate weld composition with mechanical properties.

APA, Harvard, Vancouver, ISO, and other styles

29

Sims, Helen. "Book Review: The Rights of Refugees Under International Law." Victoria University of Wellington Law Review 37, no. 4 (November 1, 2006): 643. http://dx.doi.org/10.26686/vuwlr.v37i4.5581.

Full text

Abstract:

This article is a book review of James C Hathaway The Rights of Refugees Under International Law (Cambridge University Press, New York, 2005) (1200 pages) NZ$155. In the belief that a comprehensive text on the position of refugees under international law was lacking, Hathaway has produced a book seeking to explore the nexus between human rights and refugee rights at international law, and to argue for a dynamic and purposive interpretation of the Convention Relating to the Status of Refugees. Sims praises the book's accessibility, although it is conceded by Hathaway that the book will quickly be out of date due to the area of law undergoing rapid change. Nonetheless, Sims concludes that the book is comprehensive and remains a good place to start research. By linking refugee rights to international human rights law, Hathaway provides a stronger normative basis for arguing for the continued protection of refugees under international law.

APA, Harvard, Vancouver, ISO, and other styles

30

Rzeznik, Lukasz, Yves Fleming, Tom Wirtz, and Patrick Philipp. "Experimental and simulation-based investigation of He, Ne and Ar irradiation of polymers for ion microscopy." Beilstein Journal of Nanotechnology 7 (August 2, 2016): 1113–28. http://dx.doi.org/10.3762/bjnano.7.104.

Full text

Abstract:

Secondary ion mass spectrometry (SIMS) on the helium ion microscope (HIM) promises higher lateral resolution than on classical SIMS instruments. However, full advantage of this new technique can only be obtained when the interaction of He+ or Ne+ primary ions with the sample is fully controlled. In this work we investigate how He+ and Ne+ bombardment influences roughness formation and preferential sputtering for polymer samples and how they compare to Ar+ primary ions used in classical SIMS by combining experimental techniques with Molecular Dynamics (MD) simulations and SD_TRIM_SP modelling. The results show that diffusion coefficients for He, Ne and Ar in polymers are sufficiently high to prevent any accumulation of rare gas atoms in the polymers which could lead to some swelling and bubble formation. Roughness formation was also not observed. Preferential sputtering is more of a problem, with enrichment of carbon up to surface concentrations above 80%. In general, the preferential sputtering is largely depending on the primary ion species and the impact energies. For He+ bombardment, it is more of an issue for low keV impact energies and for the heavier primary ion species the preferential sputtering is sample dependent. For He+ steady state conditions are reached for fluences much higher than 1018 ions/cm2. For Ne+ and Ar+, the transient regime extends up to fluences of 1017–1018 ions/cm2. Hence, preferential sputtering needs to be taken into account when interpreting images recorded under He+ or Ne+ bombardment on the HIM.

APA, Harvard, Vancouver, ISO, and other styles

31

Brandt, Patrick T., and John R. Freeman. "Modeling Macro-Political Dynamics." Political Analysis 17, no. 2 (2009): 113–42. http://dx.doi.org/10.1093/pan/mpp001.

Full text

Abstract:

Analyzing macro-political processes is complicated by four interrelated problems: model scale, endogeneity, persistence, and specification uncertainty. These problems are endemic in the study of political economy, public opinion, international relations, and other kinds of macro-political research. We show how a Bayesian structural time series approach addresses them. Our illustration is a structurally identified, nine-equation model of the U.S. political-economic system. It combines key features of the model of Erikson, MacKuen, and Stimson (2002) of the American macropolity with those of a leading macroeconomic model of the United States (Sims and Zha, 1998; Leeper, Sims, and Zha, 1996). This Bayesian structural model, with a loosely informed prior, yields the best performance in terms of model fit and dynamics. This model 1) confirms existing results about the countercyclical nature of monetary policy (Williams 1990); 2) reveals informational sources of approval dynamics: innovations in information variables affect consumer sentiment and approval and the impacts on consumer sentiment feed-forward into subsequent approval changes; 3) finds that the real economy does not have any major impacts on key macropolity variables; and 4) concludes, contrary to Erikson, MacKuen, and Stimson (2002), that macropartisanship does not depend on the evolution of the real economy in the short or medium term and only very weakly on informational variables in the long term.

APA, Harvard, Vancouver, ISO, and other styles

32

Ayala, J. A., W. M. Hess, F. D. Kistler, and G. A. Joyce. "Carbon-Black-Elastomer Interaction." Rubber Chemistry and Technology 64, no. 1 (March 1, 1991): 19–39. http://dx.doi.org/10.5254/1.3538537.

Full text

Abstract:

Abstract A number of different techniques were applied to measure carbon-black-surface reactivity and the level of black-polymer interaction in four different elastomer systems (SBR, IIR, NR, and NBR) representing differences in unsaturation, crystallinity and polarity. Known within-grade surface activity variations were based on partial graphitization of an N121-type carbon black. The surface activity of different black grades was studied as a function of variations in both surface area and DBPA. Direct measurements of carbon-black-surface reactivity were based on hydrogen analysis, SIMS, IGC, and moisture adsorption. In-rubber measurements included bound rubber, SIMS of cut surfaces, and an interaction parameter, σ/η, which is derived from the slope (σ) of the stress-strain curve at low elongations, and (η), the ratio of dynamic modulus (E′) at 1% and 25% DSA. The following trends were observed: 1. The σ/η values provided a good measure of black-polymer interaction in all four polymer systems for either the within-grade or across-grade comparisons. 2. Higher σ/η values were indicated for SBR and NBR, followed by NR and IIR in that order. 3. SBR indicated the greatest sensitivity for bound-rubber measurements in terms of distinguishing within-grade variations in black-polymer interaction, followed by IIR, NR, and NBR in that order. 4. Positive SIMS on dry carbon black indicates the presence of complex hydrocarbon structures suitable for chemical reactivity at the carbon-black surface. 5. SIMS analyses on the dry carbon blacks exhibited intensity variations in the negative hydrocarbon fragments which were in line with the within-grade variations in hydrogen content. 6. SIMS analyses on the cut-rubber compound surfaces showed overall variations in intensity which were proportional to the range and level of the bound-rubber measurements. The most meaningful variations were recorded for SBR and IIR. 7. Heats of adsorption derived from IGC measurements with different adsorbates showed an excellent correlation with black-polymer interaction for the within-grade studies. Measurements across grades did not correlate as well with the in-rubber measurements, but the best results were obtained using styrene as the adsorbate. 8. The within-grade moisture adsorption measurements showed excellent agreement with IGC and the other techniques for the N121 series of heat-treated carbon blacks.

APA, Harvard, Vancouver, ISO, and other styles

33

Irisarri, Maximiliano, Sofía Lavista-Llanos, Nuria M. Romero, Lázaro Centanin, Andrés Dekanty, and Pablo Wappner. "Central Role of the Oxygen-dependent Degradation Domain of Drosophila HIFα/Sima in Oxygen-dependent Nuclear Export." Molecular Biology of the Cell 20, no. 17 (September 2009): 3878–87. http://dx.doi.org/10.1091/mbc.e09-01-0038.

Full text

Abstract:

The Drosophila HIFα homologue, Sima, is localized mainly in the cytoplasm in normoxia and accumulates in the nucleus upon hypoxic exposure. We have characterized the mechanism governing Sima oxygen-dependent subcellular localization and found that Sima shuttles continuously between the nucleus and the cytoplasm. We have previously shown that nuclear import depends on an atypical bipartite nuclear localization signal mapping next to the C-terminus of the protein. We show here that nuclear export is mediated in part by a CRM1-dependent nuclear export signal localized in the oxygen-dependent degradation domain (ODDD). CRM1-dependent nuclear export requires both oxygen-dependent hydroxylation of a specific prolyl residue (Pro850) in the ODDD, and the activity of the von Hippel Lindau tumor suppressor factor. At high oxygen tension rapid nuclear export of Sima occurs, whereas in hypoxia, Sima nuclear export is largely inhibited. HIFα/Sima nucleo-cytoplasmic localization is the result of a dynamic equilibrium between nuclear import and nuclear export, and nuclear export is modulated by oxygen tension.

APA, Harvard, Vancouver, ISO, and other styles

34

Shabunin, Alexey V. "Modeling of Epidemics by Cellular Automata Lattices. SIRS Model with Reproduction and Migration." Izvestiya of Saratov University. New series. Series: Physics 20, no. 4 (2020): 278–87. http://dx.doi.org/10.18500/1817-3020-2020-20-4-278-287.

Full text

Abstract:

Background and Objectives: Methods of population dynamics give the possibility to analyze many biological phenomena by constructing simple qualitative models, which allow to understand their nature and to predict their behavior. This approach is used to study the spread of epidemics of infectious diseases in biological and human populations. The work considers a modified SIRS model of epidemic spread in the form of a lattice of stochastic cellular automata. The model uses dynamic population control with a limitation of the maximum number of individuals in the population and the influence of the disease on reproduction processes. The effect of migration is explored. Materials and Methods: Numerical simulation of the square lattice of cellular automata by means of the Monte Carlo method, investigation of synchronization of oscillations by time-series analisys and by the coherence function. Results: The considered SIRS model demonstrates irregular oscillations in the number of infected individuals at certain values of the parameters. Weak diffusion produces a significant effect on the oscillations, changing their intensity, average period and constant components. The diffusion also leads to synchronization of processes on different regions of the population. Conclusion: The behavior of the lattice cellular automata SIRS model essentially differs from that of the ordinary differential equations. In particular, it can demonstrate the oscillatory regime, which is absent in the mean field approach, as well as the phenomenon of synchronization.

APA, Harvard, Vancouver, ISO, and other styles

35

Liu, Yu, Qiu-Li Li, Guo-Qiang Tang, Xian-Hua Li, and Qing-Zhu Yin. "Towards higher precision SIMS U–Pb zircon geochronology via dynamic multi-collector analysis." Journal of Analytical Atomic Spectrometry 30, no. 4 (2015): 979–85. http://dx.doi.org/10.1039/c4ja00459k.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Muddiman, David C., Anthony J. Nicola, Andrew Proctor, and David M. Hercules. "Important Aspects concerning the Quantification of Biomolecules by Time-of-Flight Secondary-Ion Mass Spectrometry." Applied Spectroscopy 50, no. 2 (February 1996): 161–66. http://dx.doi.org/10.1366/0003702963906410.

Full text

Abstract:

Fundamental aspects regarding the use of time-of-flight secondary-ion mass spectrometry (TOF-SIMS) as a quantitative tool for the analysis of organic compounds are reported. The following factors are discussed: (1) the use of Poisson's law to correct for dead-time in single-ion data collection; (2) practical considerations concerning the analysis of “real world” samples; and (3) the effect of the etching process on the reproducibility of the intensity ratio (analyte/internal standard) of Ag-cationized species. To evaluate the importance of these factors, we used cocaine and cyclosporin A (CsA) as analytes because they show protonated and Ag-cationized species, respectively, in their SIMS spectra. Correction for detector dead-time using Poisson's law of single-ion counting expanded the dynamic range for cocaine by ∼2 orders of magnitude. For analyses requiring only a small dynamic range (i.e., CsA), the correction improved the % RSD of the slope from 2.43 to 0.87%. The maximum secondary-ion (SI) yield of CsA (Ag-cationized species) occurs at a CsA concentration ∼3 orders of magnitude higher than the therapeutic levels in blood (25–2000 ng/mL). It is discussed how this problem should be addressed. Analysis of variance (ANOVA) indicates that Ag substrates must be etched under identical conditions to obtain quantitative results when species requiring cationization are being analyzed.

APA, Harvard, Vancouver, ISO, and other styles

37

Jiang, Zhong-Xia, Jun-Liang Liu, Yan-Cong Chen, Jiang Liu, Jian-Hua Jia, and Ming-Liang Tong. "Lanthanoid single-ion magnets with the LnN10 coordination geometry." Chemical Communications 52, no. 37 (2016): 6261–64. http://dx.doi.org/10.1039/c6cc01695b.

Full text

Abstract:

Two unprecedented single-ion magnets (SIMs) with the homoatomic LnN₁₀ coordination geometry were reported, where the central Ln (Ln = Dy^III or Er^III) ion is interlocked by two pentadentate ligands (N5) affording a low symmetric polyhedron. Studies of the dynamic magnetic behaviours show an effective energy of 79(4) K for [Dy(N5)₂]³⁺ and 59(4) K for [Er(N5)₂]³⁺, respectively.

APA, Harvard, Vancouver, ISO, and other styles

38

Pucello, N., M. Rosati, G. D'Agostino, F. Pisacane, V. Rosato, and M. Celino. "Search of Molecular Ground State Via Genetic Algorithm: Implementation on a Hybrid Simd–Mimd Platform." International Journal of Modern Physics C 08, no. 02 (April 1997): 239–52. http://dx.doi.org/10.1142/s0129183197000217.

Full text

Abstract:

A genetic algorithm for the optimization of the ground-state structure of a metallic cluster has been developed and ported on a SIMD–MIMD parallel platform. The SIMD part of the parallel platform is represented by a Quadrics/APE100 consisting of 512 floating point units, while the MIMD part is formed by a cluster of workstations. The proposed algorithm is composed by a part where the genetic operators are applied to the elements of the population and a part which performs a further local relaxation and the fitness calculation via Molecular Dynamics. These parts have been implemented on the MIMD and on the SIMD part, respectively. Results have been compared to those generated by using Simulated Annealing.

APA, Harvard, Vancouver, ISO, and other styles

39

Wang, Xinxin, and Xiaoqiang Yan. "Dynamic Model of the Hot Strip Rolling Mill Vibration Resulting from Entry Thickness Deviation and Its Dynamic Characteristics." Mathematical Problems in Engineering 2019 (February 25, 2019): 1–11. http://dx.doi.org/10.1155/2019/5868740.

Full text

Abstract:

The vibration demolding of the crystallizer leads to slab thickness deviation in continuous casting processes. Therefore, in this paper, the dynamic model of the hot strip rolling mill vibration resulting from entry thickness deviation is proposed and its dynamic characteristics are studied. First, the dynamic model of vertical vibration in the hot strip rolling mill is established based on Sims’ rolling force model. Then, the model validity is certified by comparing the simulation with field test data from a 1580 hot strip rolling mill. Finally, we investigate the influence of model parameters on the dynamic characteristics of hot strip rolling mill vibration resulting from entry thickness deviation. The result indicates that hot strip rolling mill vibration resulting from entry thickness deviation can be reduced by increasing the area of the hydraulic cylinder piston side and the entry thickness as well as by decreasing the deformation resistance, rolling speed, and equivalent stiffness.

APA, Harvard, Vancouver, ISO, and other styles

40

Putter, H., S. H. Heisterkamp, J. M. A. Lange, and F. de Wolf. "A Bayesian approach to parameter estimation in HIV dynamical models." Statistics in Medicine 21, no. 15 (2002): 2199–214. http://dx.doi.org/10.1002/sim.1211.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Sui, Xiao, Bo Xu, Jiachao Yu, Oleg Kostko, Musahid Ahmed, and Xiao Ying Yu. "Studying Interfacial Dark Reactions of Glyoxal and Hydrogen Peroxide Using Vacuum Ultraviolet Single Photon Ionization Mass Spectrometry." Atmosphere 12, no. 3 (March 5, 2021): 338. http://dx.doi.org/10.3390/atmos12030338.

Full text

Abstract:

Aqueous secondary organic aerosol (aqSOA) formation from volatile and semivolatile organic compounds at the air–liquid interface is considered as an important source of fine particles in the atmosphere. However, due to the lack of in situ detecting techniques, the detailed interfacial reaction mechanism and dynamics still remain uncertain. In this study, synchrotron-based vacuum ultraviolet single-photon ionization mass spectrometry (VUV SPI-MS) was coupled with the System for Analysis at the Liquid Vacuum Interface (SALVI) to investigate glyoxal dark oxidation products at the aqueous surface. Mass spectral analysis and determination of appearance energies (AEs) suggest that the main products of glyoxal dark interfacial aging are carboxylic acid related oligomers. Furthermore, the VUV SPI-MS results were compared and validated against those of in situ liquid time-of-flight secondary ion mass spectrometry (ToF-SIMS). The reaction mechanisms of the dark glyoxal interfacial oxidation, obtained using two different approaches, indicate that differences in ionization and instrument operation principles could contribute to their abilities to detect different oligomers. Therefore, the mechanistic differences revealed between the VUV SPI-MS and ToF-SIMS indicate that more in situ and real-time techniques are needed to investigate the contribution of the air–liquid interfacial reactions leading to aqSOA formation.

APA, Harvard, Vancouver, ISO, and other styles

42

Степаненко, Сергей, Sergey Stepanenko, Василий Южаков, and Vasiliy Yuzhakov. "Exascale supercomputers. Architectural outlines." Program systems: theory and applications 4, no. 4 (November 15, 2013): 61–90. http://dx.doi.org/10.12737/2418.

Full text

Abstract:

Architectural aspects of exascale supercomputers are explored. Param-eters of the computing environment and interconnect are evaluated. It is shown that reaching exascale performances requires hybrid systems. Processor elements of such systems comprise CPU cores and arithmetic accelerators, implementing the MIMD and SIMD computing disciplines, respectively. Efficient exascale hybrid systems require fundamentally new applications and architectural efficiency scaling solutions, including: 1) process-aware structural reconfiguring of hybrid processor elements by varying the number of MIMD cores and SIMD cores communicating with them to attain as high performance and efficiency as possible under given conditions; 2) application of conflict-free sets of sources and receivers and/or decomposi-tion of the computation to subprocesses and their allocation to environment elements in accordance with their features and communication topology to minimize communication time; 3) application of topological redundancy methods to preserve the topology and overall performance achieved by the above communication time minimiza-tion solutions in case of element failure thus maintaining the efficiency reached by the above reconfiguring and communication minimization solu-tions, i.e. to provide fault-tolerant efficiency scaling. Application of these solutions is illustrated by running molecular dynamics tests and the NPB LU benchmark. The resulting architecture displays dynamic adaptability to program features, which in turn ensures the efficiency of using exascale supercomputers.

APA, Harvard, Vancouver, ISO, and other styles

43

Sima, Weiping, Meijuan Hu, Qiang He, Yixi Qiu, Yitao Lv, Lichun Dai, Qingwei Shao, et al. "Correction: Regulation of nitrogen dynamics at the sediment–water interface during HAB degradation and subsequent reoccurrence." RSC Advances 10, no. 31 (2020): 18038. http://dx.doi.org/10.1039/d0ra90050h.

Full text

Abstract:

Correction for ‘Regulation of nitrogen dynamics at the sediment–water interface during HAB degradation and subsequent reoccurrence’ by Weiping Sima et al., RSC Adv., 2020, 10, 13480–13488, DOI: 10.1039/c9ra10673a.

APA, Harvard, Vancouver, ISO, and other styles

44

Marzec, Anna, and Bolesław Szadkowski. "Improved Aging Stability of Ethylene-Norbornene Composites Filled with Lawsone-Based Hybrid Pigment." Polymers 11, no. 4 (April 19, 2019): 723. http://dx.doi.org/10.3390/polym11040723.

Full text

Abstract:

In this study, we produced a new organic-inorganic hybrid pigment based on a natural chromophore. Lawsone was selected as the active organic compound and incorporated into aluminum-magnesium hydroxycarbonate (LH). The hydroxynaphthoquinone derivative lawsone (Lawsonia inermis L.) is a naturally occurring dye, which is commonly used as a colorant because of its nontoxicity and biological functions. The structure and stability of the hybrid colorant were investigated using 27-Al solid-state nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD), secondary ion mass spectrometry (TOF-SIMS), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and UV-Vis spectroscopy. TOF-SIMS and 27Al NMR spectroscopy revealed interactions between the dye molecules and metal ions present in the LH host, confirming successful formation of an LH-based hybrid (LH/lawsone). In the next part of the study, we examined the effect of the hybrid pigment on the mechanical and thermal properties of ethylene-norbornene (EN) materials, as well as the aging resistance of the colored composites to irradiation across the full solar spectrum. Dynamic mechanical analysis (DMA) and the results of tensile break tests revealed that the EN+LH/lawsone composite had significantly better resistance to solar irradiation in comparison to EN and EN with an unmodified carrier.

APA, Harvard, Vancouver, ISO, and other styles

45

VERRAN, JOANNA, ROBERT D. BOYD, KAREN HALL, and ROBIN H. WEST. "Microbiological and Chemical Analyses of Stainless Steel and Ceramics Subjected to Repeated Soiling and Cleaning Treatments." Journal of Food Protection 64, no. 9 (September 1, 2001): 1377–87. http://dx.doi.org/10.4315/0362-028x-64.9.1377.

Full text

Abstract:

Stainless steel and ceramic surfaces were subjected to repeated soiling and cleaning procedures, using a milk powder soil inoculated with Pseudomonas aeruginosa and Staphylococcus aureus, followed by spraying with water with or without 0.1% (vol/vol) nonionic detergent. Test surfaces were removed after 1, 5, 10, and 20 soiling-cleaning cycles and were analyzed for attached microorganisms (total viable count of bacteria removed by swabbing and percentage of coverage of cells plus soil stained with acridine orange). Surfaces were additionally examined using a range of analytical techniques: X-ray photoelectron spectroscopy (XPS), dynamic and imaging secondary ion mass spectroscopy (SIMS), and time-of-flight SIMS. Both microbiological and chemical analyses revealed an accumulation of material over the cycles to a maximum level. Surfaces were conditioned rapidly to saturation with organic material within one cycle (XPS), whereas fouling by microorganisms was less rapid (five cycles). Cleaning with detergent tended to retard the cumulative fouling process when compared with spray cleaning using water alone. The methods described provide a more realistic scenario for testing the cleanability of surfaces routinely found in food processing locations and for screening novel cleaning regimens and/or surface materials. The analytical techniques provide additional information on the kinetics of soiling, which complement the more familiar microbiological methods.

APA, Harvard, Vancouver, ISO, and other styles

46

METSON, J. B., and M. J. GUSTAFSSON. "COMPLEMENTARY TECHNIQUES TO HIGH ENERGY ION BEAM ANALYSIS." Modern Physics Letters B 15, no. 28n29 (December 20, 2001): 1402–10. http://dx.doi.org/10.1142/s0217984901003329.

Full text

Abstract:

Ion beam analysis methods generally rely on either the scattering of a high energy primary particle, or secondary process arising from the stopping of this particle in the substrate. The information typically obtained is the identification and quantitation of elements present, often resolved in terms of their depth distribution. However, there are a variety of techniques which offer complementary information on the structure composition and chemistry of a surface. These are typified by rather softer interactions with the surface, typified by low energy (kV) ion beams or photons, which interact with the surface in rather more complex manner than higher energy ion beams. The combination of energy and momentum transfer for the ion beams, makes these methods less quantitative, but opens up the potential for more chemically detailed information on the nature of the surface. Secondary ion mass spectrometry (SIMS), both static and dynamic, and X-ray Photoelectron Spectroscopy (XPS) will be discussed in some detail. SIMS offers excellent compositional depth profiling capability, but offers poor quantitation, while XPS offers unparalleled chemical detail, but limited lateral and depth resolution. The underlying processes which dictate the strengths and limitations of these techniques are discussed, along with a number of typical applications to the analysis of oxide films and polymeric materials.

APA, Harvard, Vancouver, ISO, and other styles

47

Cintron-Diaz, Yarixa L., Arlet M. Acanda de la Rocha, Anthony Castellanos, Jeremy M. Chambers, and Francisco Fernandez-Lima. "Mapping chemotherapeutic drug distribution in cancer cell spheroids using 2D-TOF-SIMS and LESA-TIMS-MS." Analyst 145, no. 21 (2020): 7056–62. http://dx.doi.org/10.1039/c9an02245g.

Full text

Abstract:

Three-dimensional (3D) cancer cell cultures grown in the form of spheroids are effective models for the study of in vivo-like processes simulating cancer tumor pharmacological dynamics and morphology.

APA, Harvard, Vancouver, ISO, and other styles

48

Wang, Jian Wei, Xin Chun Shang, and Guo Cai Lv. "Molecular Dynamics Simulation of Irradiation Damage in bcc Iron." Advanced Materials Research 179-180 (January 2011): 513–18. http://dx.doi.org/10.4028/www.scientific.net/amr.179-180.513.

Full text

Abstract:

Computer simulation techniques in atom scale have now become so powerful that phenomena associated with irradiation damage effects in metals can be modelled with a high degree of realism. As a powerful tool, molecular dynamics (MD) is applied to study the displacement cascades initiated by the neutrons when they interact with matter. There exist a lot of inter-atomic potentials dedicated to bcc Fe and we choose the EAM potential. At first time PKAs (Primary knock-on atoms) knocked on a atom and send a part of energy to it what result displacement cascades. After about several ps, a lot of atoms are knocked to leave the equilibrium position and became self- interstitial atoms (SIAs). A lot of equilibrium position became vacancies. Some SIAs and vacancies form dumb-bells structure. Several vacancies or SIAs assembled the clusters. In other papers we haven’t found about the SIAs and vacancies can be assembled the SFT-like clusters in bcc Fe. In our study, we occasionally find SIAs can assemble to form the cluster in bcc Fe but need a higher energy. In our study, we choose the temperature from 100K to 600K, the energy from 100eV to 20keV. The particles scale is about 300 thousands. In a series of experimentation we find that as the temperature increase as the number of the SIAs and vacancies increase too. By the same token, as the energy increase we will find the same result.

APA, Harvard, Vancouver, ISO, and other styles

49

Song, Young Buem, and Chun Pyo Hong. "Grain Refinement of 6061 Al Alloy by the Modified Strain-Induced Melt- Activated(SIMA) Process for Semi-Solid Processing." Solid State Phenomena 119 (January 2007): 311–14. http://dx.doi.org/10.4028/www.scientific.net/ssp.119.311.

Full text

Abstract:

The dynamic process of fine grain evolution of 6061 aluminum alloy during modified strain-induced, melt-activated (SIMA) process was studied. The modified SIMA process employed casting, two stage homogenization, warm multi-forging, and recrystallization and partial melting (RAP). Multi-forging was carried out at a strain rate of 9x10-3 s-1 to accumulate high strains, with decreasing temperature from 250 to 200 °C. The alloy multi-forged with the accumulated strain of about 12 and RAP at 640 °C for 10 min exhibited the uniform equiaxed recrystallized grain structure. Accordingly, it was evident that multi-forging was very effective on grain refinement and grain size uniformity. The present modified SIMA process was discussed as an alternative thermo-mechanical processing for preparing the alloys with fine grained structure for semi solid processing.

APA, Harvard, Vancouver, ISO, and other styles

50

Arseneault, Rene. "Intercultural adjustment challenges of Korean and Canadian self-initiated expatriates in the workplace: An exploratory bidirectional investigation." International Journal of Cross Cultural Management 20, no. 2 (April 13, 2020): 181–99. http://dx.doi.org/10.1177/1470595820915630.

Full text

Abstract:

This study uses a qualitative approach and bidirectional design to explore the unique intercultural adjustment challenges that Korean and Canadian self-initiated expatriates (SIEs) experience in each other’s workplace. Through semi-structured interviews we draw upon thematic analysis to surface unique cross-cultural challenges finding that a ‘one-size’ fits all approach to understanding SIE adjustment is overly simplified and omits contextual considerations. Canadian SIEs struggled with issues related to power distance, collectivism and communication styles, whereas language barriers, individualism and hierarchical differences were major challenges for Korean SIEs. We apply our findings to previous conceptual models of cross-cultural adjustment and discuss three criteria: size of cultural gap, direction of immigration and unique contextual factors as necessary for understanding the intricate dynamics of SIE and host-country national relationships. Implications and limitations of this study are followed by recommendations for future research.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Dynamická SIMS'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles