An Empirical Study on the factors influencing the utilization and the effectiveness of Enterprise Instant Messenger

Communication technology has been recognized to play an important role in boosting organization’s competitiveness and viability by facilitating efficient communication and information sharing. Lately, many organizations began to actively adopt the self-developed Enterprise Instant Messenger (EIM) as a common organizational communication medium after experiencing security problem with public messengers like MSN. Its utilization and tangible benefits of EIM, however, vary. There’s an urgent need to understand how each organization embraces EIM and to empirically evaluate whether active use of EIM can result in a better communication, eventually leading into better business productivity. In this research we try to investigate those antecedents which may have affected the high use of EIM and a better decision making efficiency. Theoretical justification of research variables and causal relationships of our research model are mainly based on Technology Acceptance Model (TAM), media selection theory, and social influence model. Through a survey data analysis of 171 EIM users, it was found that perceived usefulness, social influence, the externally-orientated organizational culture had a significant effect on the high use of EIM. In addition, the use of EIM was found to have a significant effect on the efficiency in the decision-making process

Singlet fermionic dark matter

We propose a renormalizable model of a fermionic dark matter by introducing a gauge singlet Dirac fermion and a real singlet scalar. The bridges between the singlet sector and the standard model sector are only the singlet scalar interaction terms with the standard model Higgs field. The singlet fermion couples to the standard model particles through the mixing between the standard model Higgs and singlet scalar and is naturally a weakly interacting massive particle (WIMP). The measured relic abundance can be explained by the singlet fermionic dark matter as the WIMP within this model. Collider implication of the singlet fermionic dark matter is also discussed. Predicted is the elastic scattering cross section of the singlet fermion into target nuclei for a direct detection of the dark matter. Search of the direct detection of the dark matter provides severe constraints on the parameters of our model.Comment: 12 pages, 7 figure

Ultracold Neutron Production in a Pulsed Neutron Beam Line

We present the results of an Ultracold neutron (UCN) production experiment in a pulsed neutron beam line at the Los Alamos Neutron Scattering Center. The experimental apparatus allows for a comprehensive set of measurements of UCN production as a function of target temperature, incident neutron energy, target volume, and applied magnetic field. However, the low counting statistics of the UCN signal expected can be overwhelmed by the large background associated with the scattering of the primary cold neutron flux that is required for UCN production. We have developed a background subtraction technique that takes advantage of the very different time-of-flight profiles between the UCN and the cold neutrons, in the pulsed beam. Using the unique timing structure, we can reliably extract the UCN signal. Solid ortho-D$_2$ is used to calibrate UCN transmission through the apparatus, which is designed primarily for studies of UCN production in solid O$_2$. In addition to setting the overall detection efficiency in the apparatus, UCN production data using solid D$_2$ suggest that the UCN upscattering cross-section is smaller than previous estimates, indicating the deficiency of the incoherent approximation widely used to estimate inelastic cross-sections in the thermal and cold regimes

New Gauge Invariant Formulation of the Chern-Simons Gauge Theory

A new gauge invariant formulation of the relativistic scalar field interacting with Chern-Simons gauge fields is considered. This formulation is consistent with the gauge fixed formulation. Furthermore we find that canonical (Noether) Poincar\'e generators are not gauge invariant even on the constraints surface and do not satisfy the (classical) Poincar\'e algebra. It is the improved generators, constructed from the symmetric energy-momentum tensor, which are (manifestly) gauge invariant and obey the classical Poincar\'e algebra.Comment: Shortened, to appear as Papid Communication-PRD/Nov/9

Design and Optimization of Coin-Shaped Microreactor Chips for PET Radiopharmaceutical Synthesis

An integrated elastomeric microfluidic device, with a footprint the size of a postage stamp, has been designed and optimized for multistep radiosynthesis of PET tracers. Methods: The unique architecture of the device is centered around a 5-µL coin-shaped reactor, which yields reaction efficiency and speed from a combination of high reagent concentration, pressurized reactions, and rapid heat and mass transfer. Its novel features facilitate mixing, solvent exchange, and product collection. New mixing mechanisms assisted by vacuum, pressure, and chemical reactions are exploited. Results: The architecture of the reported reactor is the first that has allowed batch-mode microfluidic devices to produce radiopharmaceuticals of sufficient quality and quantity to be validated by in vivo imaging. Conclusion: The reactor has the potential to produce multiple human doses of ^(18)F-FDG; the most impact, however, is expected in the synthesis of PET radiopharmaceuticals that can be made only with low yields by currently available equipment

Scaling Behavior of Barkhausen Avalanches along the Hysteresis loop in Nucleation-Mediated Magnetization Reversal Process

We report the scaling behavior of Barkhausen avalanches for every small field step along the hysteresis loop in CoCrPt alloy film having perpendicular magnetic anisotropy. Individual Barkhausen avalanche is directly observed utilizing a high-resolution soft X-ray microscopy that provides real space images with a spatial resolution of 15 nm. Barkhausen avalanches are found to exhibit power-law scaling behavior at all field steps along the hysteresis loop, despite their different patterns for each field step. Surprisingly, the scaling exponent of the power-law distribution of Barkhausen avalanches is abruptly altered from 1 {+-} 0.04 to 1.47 {+-} 0.03 as the field step is close to the coercive field. The contribution of coupling among adjacent domains to Barkhausen avalanche process affects the sudden change of the scaling behavior observed at the coercivity-field region on the hysteresis loop of CoCrPt alloy film

On the behavior of micro-spheres in a hydrogen pellet target

A pellet target produces micro-spheres of different materials, which are used as an internal target for nuclear and particle physics studies. We will describe the pellet hydrogen behavior by means of fluid dynamics and thermodynamics. In particular one aim is to theoretically understand the cooling effect in order to find an effective method to optimize the working conditions of a pellet target. During the droplet formation the evaporative cooling is best described by a multi-droplet diffusion-controlled model, while in vacuum, the evaporation follows the (revised) Hertz-Knudsen formula. Experimental observations compared with calculations clearly indicated the presence of supercooling, the effect of which is discussed as well.Comment: 22 pages, 8 figures (of which two are significantly compressed for easier download