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Nguyen Ngoc Duy,Latsamy Xayavong,Nguyen Kim Uyen,Vinh Nguyen Thanh Pham,Tran Viet Nhan Hao 한국물리학회 2019 새물리 Vol.69 No.10
Nuclear physics is an obligatory subject for the general physics program of undergraduates in most of the natural science universities worldwide. In nuclear physics, the shell model is one of the most important models, and is well used to determine the spin-parity and the magnetic moment of a nucleus. Over ten years of teaching general physics, we have realize that most undergraduate students find calculating these parameters by using this shell model to be difficult due to the classification of the subshells and the intrinsic spin of nucleons. With the hope to help these students, in the present study, we introduce a graphical-user-interface (GUI) program to execute our selfdeveloped Shell Model Calculator (SMC) code written in the Visual Basic 6.0 (VB6) programming language. Our SMC validation results for the quantum quantities in a series of nuclei Z = 1 - 20 were compared with experimental data and found to be in good agreement. In general, we successfully developed an SMC program that can be used for teaching, learning, and researching nuclear physics in universities.
Ly Nguyen Duy,Xayavong Latsamy,Uyen Nguyen Kim,Pham Vinh N. T.,Hao T. V. Nhan,Duy Nguyen Ngoc 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.11
The present paper reports on the spin-parities and the magnetic moments for the ground states of 44 proton-rich isotopes with Z = 21-30 and A = 36-57, which are important for studies of either reaction rates in X-ray bursts or nuclear structure. These nuclear properties were calculated based on the single-particle shell model. The spins of the concerned nuclei were compared to available experimental data adopted from the NuDat database to evaluate the variations in the astrophysical rates of the rp-process reactions. We found discrepancies, due to the deformed nuclear structure, between the present results and those reported in the NuDat database. The spin uncertainties result in large variations, 13% - 200%, in the astrophysical rates of the rp-process reactions. In particular, the spin uncertainties of the 44V and the 46-49Mn isotopes significantly affect the astrophysical rates of the reverse reactions of the proton captures 43Ti(p,γ)44V$(p,γ)45Cr, 45Cr(p,γ)46Mn(p,γ)47Fe, 47Mn(p,γ)48Fe, 47Cr(p,γ)48Mn(p,γ)49Fe, and 48Cr(p,γ)49Mn(p,γ)50Fe. Moreover, the magnetic moments of most of the isotopes were predicted for the first time. The results show that the magnetic moments are in the order of μp(1f7/2) > μp(2p3/2) > μn(1d3/2)> μn(1f7/2) for the nuclei having an unpaired nucleon in the proton/neutron shells. The present study suggests that reliable calculations and/or measurements for the properties of proton-rich nuclei are highly demanded.
Uyen, Nguyen To,Park, Suk-Youl,Choi, Ji-Woo,Lee, Hyun-Ju,Nishi, Kosuke,Kim, Jeong-Sun Oxford University Press 2009 Nucleic acids research Vol.37 No.20
<P>Among four types of bacterial restriction enzymes that cleave a foreign DNA depending on its methylation status, type I enzymes composed of three subunits are interesting because of their unique DNA cleavage and translocation mechanisms performed by the restriction subunit (HsdR). The elucidated N-terminal fragment structure of a putative HsdR subunit from <I>Vibrio vulnificus</I> YJ016 reveals three globular domains. The nucleolytic core within an N-terminal nuclease domain (NTD) is composed of one basic and three acidic residues, which include a metal-binding site. An ATP hydrolase (ATPase) site at the interface of two RecA-like domains (RDs) is located close to the probable DNA-binding site for translocation, which is far from the NTD nucleolytic core. Comparison of relative domain arrangements with other functionally related ATP and/or DNA complex structures suggests a possible translocation and restriction mechanism of the HsdR subunit. Furthermore, careful analysis of its sequence and structure implies that a linker helix connecting two RDs and an extended region within the nuclease domain may play a central role in switching the DNA translocation into the restriction activity.</P>
Re-examination of Energy-Loss Straggling Calculations of Alpha Particles at 5.486 MeV
Nguyen Ngoc Duy,Nguyen Kim Uyen,Vinh N. T. Pham 한국물리학회 2020 New Physics: Sae Mulli Vol.70 No.2
We report on an evaluation of energy-loss straggling calculations performed using the LISE++ code and theoretical models. The energy-loss straggling of the alpha particles at 5.486 MeV in Al, Cu, Ag, Tb, Ta, and Au was calculated by using the LISE++ code and the Titeica model. The results of the calculations were compared to the measured data to improve the accuracy of the straggling predictions. The results show that the straggling is increased by the energy loss at a rate of 8.0 keV/%. The uncertainties of the LISE++ and Titeica calculations were reduced to about 15% by adding fitting parameters. We also propose a new semi-empirical formula which well reproduces the measured data with an uncertainty of about 20% for 5.486-MeV alpha particles in the materials used in the research.
Development of porous silicon-coated gold nanoparticles as potential theragnostic material
Jiwon Kim,Sumin Hwang,Quy Son Luu,Donghyuk Jo,Uyen Thi Do,Quynh Thi Nguyen,Jae-Sung Kwon,Seunghyun Lee,Youngbok Lee 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.12
Gold nanoparticles (AuNPs) have been used widely as multifunctional materials for several biomedical applications due to their attractive characteristics. However, toxicity and aggregation of AuNPs are critical issues, and methods of effective surface modification are required to overcome these problems. In this study, porous silicon-coated gold nanoparticles (AuNP@pSi) were fabricated as a hybrid nanocomposite capable of surface-enhanced Raman scattering (SERS)-sensing and drug carrier. First, size-controlled AuNPs were coated with a silica nano-shell, and the resulting silica layers were converted to porous silicon through magnesiothermic reduction. Overall results suggest that AuNP@pSi can be exploited as a SERS probe with efficient Raman signal improvement of benzenethiol as well as a drug carrier based on its high surface area (113.7 m2 g?1) and porosity (13.38?nm, 0.3805?cm3 g?1). Since the porous silicon possibly can serve as magnetic resonance imaging probes with DNP technology, this hybrid platform potentially can be utilized as powerful material capable of theragnosis system.
Duy Nguyen Ngoc,Ho Phuong-Thao,Uyen Nguyen Kim 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.10
We report on the variations of the astrophysical rates due to mass uncertainties of the exotic nuclei in rp-process reactions. With the current mass precision obtained in the AME2016 database, only the 71Br(p,γ)72Kr and the 65As(p,γ)66Se reactions have rate uncertainties of about 10% - 20% at T9 = 0.5 while the 61Ga(p,γ)62Ge, 61, 64, 65Ge(p,γ)62, 65, 66As, 68, 69Se(p,γ)^{69, 70}Br, 69,70Br(p,γ)70,71Kr, and 75Rb(p,γ)76Sr reactions have large uncertainties of more than 50%. If an uncertainty of 10% at T9 = 1.0 is to be achieved, the mass precisions for the isotopes must be less than 10 keV. Evaluations of the photodisintegrations corresponding to proton captures and β+ decays of the waiting points, 64Ge and 68Se, indicate that the orientation of the nucleosynthesis at these waiting points is still unknown due to the large astrophysical rate variations because of the mass uncertainties of the 65As and the 69Br isotopes. The astrophysical rate variations corresponding to the mass precision levels at specific temperatures are presented in this work.
MRTOF-S: a toolkit for pre-estimating precise mass measurements using MRTOF spectrometer
Duy Nguyen Ngoc,Uyen Nguyen Kim,채경육 한국물리학회 2022 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.80 No.9
An accurate estimation of the masses of exotic nuclei is important for obtaining a better understanding of the nuclear structure and for astrophysical calculations. Because most nuclear masses of unstable isotopes far from beta stability are highly uncertain, precise mass measurements are necessary. Among recent advanced techniques, the multiple-reflection time-of-flight (MRTOF) has emerged as a good device for measuring the precise masses of short-lived isotopes with high mass-resolving power. Before conducting mass measurements in laboratories, it is necessary to pre-estimate the beam production rate, separability of ions, mass resolving power, etc. Hence, a computer code named MRTOF simulator (MRTOF-S) was developed. In this study, we report the development procedure, usage, and application of the MRTOF-S toolkit.