Laser spectroscopy of NiI: Ground and low-lying electronic states

Rotationally resolved near-infrared and visible spectroscopic studies of the ground and low-lying electronic states of NiI were performed using the technique of laser vaporization/reaction with free jet expansion and laser-induced fluorescence (LIF) spectroscopy. Two electronic transitions as well as isotopic molecules were analyzed. The electronic configurations that give rise to the X 2∏ 3/2 ground state for NiF, NiCl, and NiBr were determined.published_or_final_versio

Efficient HMAC-based secure communication for VANETs

Vehicular Ad Hoc Network (VANET) is an emerging type of network which facilitates vehicles on roads to communicate for driving safety. It requires a mechanism to help authenticate messages, identify valid vehicles, and remove malevolent vehicles which do not obey the rules. Most existing solutions either do not have an effective message verification scheme, or use the public key infrastructure (PKI). In this network, vehicles are able to broadcast messages to other vehicles and a group of known vehicles can also communicate securely among themselves. So group communication is necessary for the network. However, most existing solutions either do not consider this or use pairing operation to realize this. They are either not secure or not effective. In this paper, we provide a more comprehensive set of secure schemes with Hash-based Message Authentication Code (HMAC) in VANETs to overcome their shortcomings. Of course, we still need to use Pairing operation in some place. Our scheme is composed of three schemes: (1) Communications between Vehicles and Road-Side Units (RSUs), (2) One to One Communications within a Group, (3) One to One Communications without a Group. Based on our simulation study, we show that our schemes are effective and the delay caused is much lower. The average delay caused by our first scheme is nearly thousands of times lower than prior schemes. The average delay caused by our second scheme is 0.312 ms, while the delay caused by prior scheme is 12.3 ms. Meanwhile the average delay caused by our third scheme is 0.312 ms, and the delay caused by prior scheme is about 9 s. © 2012 Elsevier B.V. All rights reserved.postprin

High-Performance Light Field Reconstruction with Channel-wise and SAI-wise Attention

© Springer Nature Switzerland AG 2019. Light field (LF) images provide rich information and are suitable for high-level computer vision applications. To acquire capabilities of modeling the correlated information of LF, most of the previous methods have to stack several convolutional layers to improve the feature representation and result in heavy computation and large model sizes. In this paper, we propose channel-wise and SAI-wise attention modules to enhance the feature representation at a low cost. The channel-wise attention module helps to focus on important channels while the SAI-wise attention module guides the network to pay more attention to informative SAIs. The experimental results demonstrate that the baseline network can achieve better performance with the aid of the attention modules

A role for metamemory in cognitive offloading

Cognitive offloading refers to our reliance on the external environment in order to reduce cognitive demand. For instance, people write notes on paper or smartphones in order not to forget shopping lists or upcoming appointments. A plausible hypothesis is that such offloading relies on metamemory - our confidence in our future memory performance. However, this hypothesis has not been directly tested, and it remains unclear when and how people use external sources to aid their encoding and retrieval of information. In four experiments, here we asked participants to learn word pairs and decide whether to offload some of the pairs by "saving" them on a computer. In the memory test, they had the opportunity to use this saved information on half of trials. Participants adaptively saved the most difficult items and used this offloaded information to boost their memory performance. Crucially, participants' confidence judgments about their memory predicted their decisions to use the saved information, indicating that cognitive offloading is associated with metacognitive evaluation about memory performance. These findings were accommodated by a Bayesian computational model in which beliefs about the performance boost gained from using offloaded information are negatively coupled to an evaluation of memory ability. Together our findings highlight a close link between metamemory and cognitive offloading

Broadband characterisation of interior materials and surface scattering using terahertz time-domain spectroscopy

Indoor wireless communications need to move towards Terahertz (THz) frequencies in order to keep up with society's demand for data transmission, but this change is currently hindered by limited knowledge of material properties and propagation and scattering models at these frequencies. The dielectric properties of common household materials are investigated here with a twofold objective: (1) to extend the library of material properties at THz, and (2) to estimate and disentangle losses in scattering measurements in order to facilitate propagation, scattering and, ultimately, channel models

Room temperature line lists for deuterated water

Line lists are presented for six deuterated isotopologues of water vapor namely HD16O, HD17O, HD18O, D16 2 O, D17 2 O and D18 2 O. These line lists are prepared using empirically-determined energy levels, where available, to provide transition frequencies and high-quality ab initio dipole moment surfaces to provide transition intensities. The reliability of the predicted intensities is tested by computing multiple line lists and analyzing the stability of the results. The resulting intensities are expected to be accurate to a few percent for well-behaved, stable transitions. Complete T = 296 K line lists are provided for each species

Geometric phase outside a Schwarzschild black hole and the Hawking effect

We study the Hawking effect in terms of the geometric phase acquired by a two-level atom as a result of coupling to vacuum fluctuations outside a Schwarzschild black hole in a gedanken experiment. We treat the atom in interaction with a bath of fluctuating quantized massless scalar fields as an open quantum system, whose dynamics is governed by a master equation obtained by tracing over the field degrees of freedom. The nonunitary effects of this system are examined by analyzing the geometric phase for the Boulware, Unruh and Hartle-Hawking vacua respectively. We find, for all the three cases, that the geometric phase of the atom turns out to be affected by the space-time curvature which backscatters the vacuum field modes. In both the Unruh and Hartle-Hawking vacua, the geometric phase exhibits similar behaviors as if there were thermal radiation at the Hawking temperature from the black hole. So, a measurement of the change of the geometric phase as opposed to that in a flat space-time can in principle reveal the existence of the Hawking radiation.Comment: 14 pages, no figures, a typo in the References corrected, version to appear in JHEP. arXiv admin note: text overlap with arXiv:1109.033

Exploring the Intrabinary Shock from the Redback Millisecond Pulsar PSR J2129-0429

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Electric-field-induced alignment of electrically neutral disk-like particles: modelling and calculation

This work reveals a torque from electric field to electrically neutral flakes that are suspended in a higher electrical conductive matrix. The torque tends to rotate the particles toward an orientation with its long axis parallel to the electric current flow. The alignment enables the anisotropic properties of tiny particles to integrate together and generate desirable macroscale anisotropic properties. The torque was obtained from thermodynamic calculation of electric current free energy at various microstructure configurations. It is significant even when the electrical potential gradient becomes as low as 100 v/m. The changes of electrical, electroplastic and thermal properties during particles alignment were discussed