Focal Spot, Winter 1983/84

https://digitalcommons.wustl.edu/focal_spot_archives/1036/thumbnail.jp

Direct observation of ordered trimers on Si(111)√3×√3 R30°-Au by scanned-energy glancing-angle Kikuchi electron wave-front reconstruction

We report the first atomically resolved images of ordered Au trimers on Si(111)√3×√3R30°-Au using wave-front reconstruction of scanned-energy glancing-angle Kikuchi electron spectra. Each Au image has a resolution (full width at half magnitude) of less than 1 Å . The images indicate that Au trimers are ordered and nonrotated within the surface plane and with respect to the second-layer Si plane providing direct evidence of the conjugate honeycomb-chained-trimer model for the Au-√3 system. © 1996 The American Physical Society.published_or_final_versio

2-Chloro­pyridine-3-carboxamide

In the crystal structure of the title compound, C6H5ClN2O, the dihedral angle between the pyridine ring and the carboxamine group is 63.88 (8)°. Inter­molecular N—H⋯N and N—H⋯O hydrogen bonds link the mol­ecules into a two-dimensional network

1-(3-Chloro­benz­yloxy)urea

The asymmetric unit of the crystal structure of the title compound, C8H9ClN2O2, contains four independent mol­ecules. The dihedral angles between the urea N—(C=O)—N planes and the benzene rings are 83.3 (3), 87.8 (1), 89.1 (1) and 17.5 (2)° in the four mol­ecules. Extensive N—H⋯O hydrogen bonding is present in the crystal structure

Degenerate Rabi spectroscopy of the Floquet engineered optical lattice clock

Simulating physics with large SU(N) symmetry is one of the unique advantages of Alkaline-earth atoms.Introducing periodical driving modes to the system may provide more rich SU(N) physics that static one could not reach. However, whether the driving modes will break the SU(N) symmetry is still lack of discussions. Here we experimentally study a Floquet engineered degenerate Sr-87 optical lattice clock (OLC) by periodically shaking the lattice. With the help of Rabi spectroscopy, we find that the atoms at different Zeeman sublevels are tuned by the same driven function. Meanwhile, our experimental results suggest that uniform distribution among the sublevels will not change despite the driving. Our experimental demonstrations may pave the way to implementation of FE on tailoring the SU(N) physics in OLC system

A Pseudo DNA Cryptography Method

The DNA cryptography is a new and very promising direction in cryptography research. DNA can be used in cryptography for storing and transmitting the information, as well as for computation. Although in its primitive stage, DNA cryptography is shown to be very effective. Currently, several DNA computing algorithms are proposed for quite some cryptography, cryptanalysis and steganography problems, and they are very powerful in these areas. However, the use of the DNA as a means of cryptography has high tech lab requirements and computational limitations, as well as the labor intensive extrapolation means so far. These make the efficient use of DNA cryptography difficult in the security world now. Therefore, more theoretical analysis should be performed before its real applications. In this project, We do not intended to utilize real DNA to perform the cryptography process; rather, We will introduce a new cryptography method based on central dogma of molecular biology. Since this method simulates some critical processes in central dogma, it is a pseudo DNA cryptography method. The theoretical analysis and experiments show this method to be efficient in computation, storage and transmission; and it is very powerful against certain attacks. Thus, this method can be of many uses in cryptography, such as an enhancement insecurity and speed to the other cryptography methods. There are also extensions and variations to this method, which have enhanced security, effectiveness and applicability.Comment: A small work that quite some people asked abou

Safety Indicator for Taxi Users In Urban Area

Transportation service provided as social responsibility in many country including Malaysia should always be safe and perceived as safe by everyone. However, many studies had found that the increasing level of crime had cause the level of fear increase as well. Thus this had effected the ridership drop on almost all public transport usage especially taxi. Therefore it is the main intention of this paper to look at the different factors affecting the level of safety indication among taxi users in urban area. The paper provide an overview of the factors explaining on how different level of travel satisfaction through a quantitative research method where a personal administered survey was conducted among the taxi users who is living and commuting to the city center using taxi service. One of the significant findings shows that certain element such as driver attitude, age and technology indicate a significant roles as travel safety indicator. As this study only focus in urban area in Klang Valley, therefore the finding cannot be generalize to other area. Among the implication of the findings is that, future planner should take into consideration all factors that could possibly create a low signal of safety level among taxi users. This paper highlight the fear reduction model through a Malaysian empirical evidence which hold a high level of novelty where the application is suitable in Malaysian context urban travelers especially when reducing level of fear among taxi users is concern

Quantumness and quantum to classical transition in the generalized Rabi model

The quantum to classical transition (QCT) is one of the central mysteries in quantum physics. This process is generally interpreted as state collapse from measurement or decoherence from interacting with the environment. Here we define the quantumness of a Hamiltonian by the free energy difference between its quantum and classical descriptions, which vanishes during QCT. We apply this criterion to the many-body Rabi model and study its scaling law across the phase transition, finding that not only the temperature and Planck constant, but also all the model parameters are important for this transition. We show that the Jaynes-Cummings and anti Jaynes-Cummings models exhibit greater quantumness than the Rabi model. Moreover, we show that the rotating wave and anti-rotating wave terms in this model have opposite quantumness in QCT. We demonstrate that the quantumness may be enhanced or suppressed at the critical point. Finally, we estimate the quantumness of the Rabi model in current trapped ion experiments. The quantumness provides an important tool to characterize the QCT in a vast number of many-body models.Comment: 6 pages, 5 figure