Spectral properties of the surface reflectance of the northern polar region of Mercury

We analyse MESSENGER reflectance measurements covering the northern polar region of Mercury, the least studied region of the northern mercurian hemisphere. We use observations from the Mercury Dual Imaging System Wide-Angle Camera (MDIS/WAC) and the Mercury Atmospheric and Surface Composition Spectrometer (MASCS/VIRS) to study the spectral dependence of the surface reflectance. The results obtained from the observations made by both instruments are remarkably consistent. We find that a second degree polynomial description of the measured reflectance spectra gives very good fits to the data and that the information that they carry can best be characterized by two parameters, the mean reflectance and the mean relative spectral slope, averaged over the explored range of wavelengths. The properties of the four main types of terrains known to form Mercury's regolith in the northern region, smooth plains (SP), heavily cratered terrain (HCT), fresh ejecta/materials and red pitted ground (RPG) are examined in terms of these two parameters. The results are compared, and found consistent with those obtained by earlier studies in spite of difficulties met in obtaining accurate reflectance measurements under the large incidence angle condition characteristic of polar regions. These results will help with the preparation of the BepiColombo mission and with supporting its observational strategy.Comment: 21 pages, 15 figures, accepted for publication in Research in Astronomy and Astrophysic

Further Discussion On Applying Case Study Method In Investment Law Course – A Case Of Education Investment In Vietnam

Purpose: The aim of this study is to focus on clarifying using case study method to improve taching law course. Currently, many universities around the world are applying a new teaching method. It can help students absorb knowledge more efficiently and faster. That is the case study. Using a Case Study allows a deeper understanding of cases as a unit, through comparing the similarities and differences of individual cases. Design/methodology/approach: The study uses qualitative analysis, synthesis and inductive methods, together with studies and references from CPTPP, FTA Agreement, as well as Regulations on assurance of business investment activities. Findings: The application of this method to teaching helps learners to approach very applicable situations. The situations or problems close to the theory will also help them to systematize all the knowledge they have learned to apply to solve the assigned problem. Not only use the knowledge learned, but also learn related knowledge outside the program to solve the problem. Case Study is an extremely interesting and interesting learning method, helping us to associate reality and apply it to solve problems and help us remember longer. If you really understand what a case study is, then apply it to your life and work. The results show the regulations on guaranteeing ownership rights as well as ensuring investors' business investment activities have been clearly stipulated in the 2020 Labor Law of Vietnam. These regulations have concretized the constitutional principle of investors' freedom to invest and do business in industries that are not prohibited by la

The VATLY Radio Telescope

A small radio telescope (SRT) has been installed on the roof of the Hanoi astrophysics laboratory VATLY. It is equipped with a 2.6 m diameter mobile parabolic dish remotely controlled in elevation and azimuth and with super-heterodyne detection around the 21 cm hydrogen line. First results of observations of the Sun and of the centre of the Milky Way are presented. They demonstrate the high quality of the telescope performance and are used to evaluate lobe size, signal to noise ratios, anthropogenic interferences and measurement accuracies. Particular attention is given to the measurement of the pointing accuracy. The rich measurement programme that is now at hand is briefly sketched

Simulation of proton-induced and iron-induced extensive air showers at extreme energies

The development of extensive air showers at extreme energies is studied using a simulation model much simpler and cruder, but also more transparent and flexible, than existing sophisticated codes. Evidence for its satisfactory performance is presented. As an illustration, shower elongation rates are evaluated in the $10^{18}$ to $10^{20}$ eV region and compared with recently published data. Lateral distribution functions of both muons and electrons/photons are also briefly discussed. Reliable results are obtained in the comparison between proton-induced and iron-induced showers.Comment: 22 pages, Preprint submitted to Astroparticle Physic

Numerical modeling of thermal dust polarization from aligned grains in the envelope of evolved stars with updated POLARIS

Magnetic fields are thought to influence the formation and evolution of evolved star envelopes. Thermal dust polarization from magnetically aligned grains is potentially a powerful tool for probing magnetic fields and dust properties in these circumstellar environments. In this paper, we present numerical modeling of thermal dust polarization from the envelope of IK Tau using the magnetically enhanced radiative torque (MRAT) alignment theory implemented in our updated POLARIS code. Due to the strong stellar radiation field, the minimum size required for RAT alignment of silicate grains is $\sim 0.005 - 0.05\,\rm\mu m$. Additionally, ordinary paramagnetic grains can achieve perfect alignment by MRAT in the inner regions of $r < 500\,\rm au$ due to stronger magnetic fields of $B\sim 10$ mG - 1G, producing thermal dust polarization degree of $\sim 10\,\%$. The polarization degree can be enhanced to $\sim 20-40\%$ for grains with embedded iron inclusions. We also find that the magnetic field geometry affects the alignment size and the resulting polarization degree due to the projection effect in the plane-of-sky. We also study the spectrum of polarized thermal dust emission and find the increased polarization degree toward $\lambda > 50\,\rm\mu m$ due to the alignment of small grains by MRAT. Furthermore, we investigate the impact of rotational disruption by RATs (RAT-D) and find the RAT-D effect cause a decrease in the dust polarization fraction. Finally, we compare our numerical results with available polarization data observed by SOFIA/HAWC+ for constraining dust properties, suggesting grains are unlikely to have embedded iron clusters and might have slightly elongated shapes. Our modeling results suggest further observational studies at far-infrared/sub-millimeter wavelengths to understand the properties of magnetic fields and dust in AGB envelopes.Comment: 27 pages, 23 figures, 1 table, to be submitte

Evaluation of Lecture Hall Service and Infrastructures Construction Rules of Vietnam Universities Via A Case of Neu in Hanoi

Building a university design regulations and standards is not only necessary for units in the industry but also contributes to bringing to society modern educational models, suitable to the economic conditions of the country. The standard applies to the design, renovation and new design of university buildings throughout Vietnam, based on the document issued by the Ministry of Construction No. TCVN 3981:1985. This paper also suggest: Improve the quality of the teaching /lecture service staff. First, Develop a reasonable monitoring, evaluation and reward mechanism to motivate people to work hard; Second, Each faculty member on duty has a job description with clear responsibilities, rights and obligations; Third, Conduct ongoing training. It is necessary to regularly organize training and training courses on serving, communicating, and dealing with customers

Factors affecting ecotourism loyalty with the moderating role of social influence - Empirical evidence in Vietnam

Today, ecotourism has become more common and attractive for tourists who love to explore nature and experience the cultural heritage. In the 4.0 age of technology, social networking not only helps visitors find suitable destinations to visit easily but also provides visitors with a place to leave comments or reviews after the trips. This study aims to qualify the relationships between electronic-worth-of-mouth (eWOM), social influence (SI), destination image (DI), tourist satisfaction (SAT), and ecotourism loyalty (EL). The study applied the PLS-SEM model to estimate 499 observations at ecotourism sites in Vietnam as empirical evidence. The research results show that all the factors in the research model have positive and significant effects on EL. In particular, DI and SAT, directly and indirectly, affect EL; while eWOM and SI only have direct effects on EL. Additionally, it was found that the effect of eWOM on EL increased with the moderating role of SI. © 2022 Editura Universitatii din Oradea. All rights reserved.Univerzita Tomáše Bati ve Zlín