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.

Predictors of twin pregnancy in in vitro fertilization with intracytoplasmic sperm injection cycles with day 3 double embryo transfer

Duy Le Nguyen,Hieu Le-Trung Hoang,Vu Ngoc-Anh Ho,Toan Duong Pham,Nam Thanh Nguyen,Van Thi-Thu Tran,Tuong Manh Ho,Lan Ngoc Vuong The Korean Society for Reproductive Medicine 2024 Clinical and Experimental Reproductive Medicine Vol.51 No.1

Objective: The purpose of this study was to identify factors associated with twin pregnancy following day 3 double embryo transfer (DET). Methods: This retrospective cohort study incorporated data from 16,972 day 3 DET cycles. The participants were women aged between 18 and 45 years who underwent in vitro fertilization with intracytoplasmic sperm injection (IVF/ICSI) at My Duc Assisted Reproduction Technique Unit (IVFMD), My Duc Hospital, located in Ho Chi Minh City, Vietnam. Results: Of the 16,972 day 3 DET cycles investigated, 8,812 (51.9%) resulted in pregnancy. Of these, 6,108 cycles led to clinical pregnancy, with 1,543 (25.3% of clinical pregnancies) being twin pregnancies. Factors associated with twin pregnancy included age under 35 years (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.32 to 1.71; p<0.001) and cycles involving the transfer of at least one grade I embryo. Relative to the transfer of two grade III embryos, the risk of twin pregnancy was significantly elevated following the transfer of two grade I embryos (OR, 1.40; 95% CI, 1.16 to 1.69; p<0.001) or a combination of one grade I and one grade II embryo (OR, 1.27; 95% CI, 1.05 to 1.55; p=0.001). Conclusion: By analyzing a large number of IVF/ICSI cycles, we identified several predictors of twin pregnancy. These findings can assist medical professionals in tailoring treatment strategies for couples with infertility.

An Approximation of the Synthesis Cross Section for the Unknown 126th Element via 58Ni + 251Cf and 64Zn + 248Cm Combinations

Duy Nguyen Ngoc,Ho Phuong-Thao,Pham Vinh N. T.,Hoan Nguyen Thi Thu 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.1

In this paper, we estimate the production cross section of the unknown super-heavy nuclei 309, 312126 via 58Ni + 251Cf and 64Zn + 248Cm combinations by using approximation methods. For each reaction, the competition between compound nucleus (CN) formation and quasi-fission process is also analyzed. We found that the synthesis cross section for the 309126 isotope is about 3 fb, which is about 5 orders of magnitude higher than that for the 312126 nucleus. The results also suggest that a valley exists around the isotope with A = 313 in the production yields for the 126th element. Moreover, the synthesis of the 310-317126 isotopes is still a challenge for experimental techniques due to the small cross sections, which are less than 1 fb.

Potential of Visual Basic 6.0 in Teaching and Studying Physics

Duy Nguyen Ngoc 한국물리학회 2022 새물리 Vol.72 No.7

Computer programs play an important role in education and studies on subjects in natural science. Using computers, distance teaching and studying physics became easier, especially during the Covid-19 pandemic. Visual Basic 6.0 has emerged among various programming languages as a potential tool for physicists due to its simplicity and interactive graphical interface. This programming language does not require users' extensive computer knowledge or programming skills. With the hope of enhancing the efficiency of teaching and studying physics, I hereby present Visual Basic 6.0 potential to create graphical-user-interface (GUI) computer programs for creating a virtual laboratory, simulations, and numerical calculations. This study is used to enhance the effectiveness of computer programs in teaching, learning and doing research in physics.

Examination of the Astrophysical-Rate Variations of the Key Reactions in the rp-Process due to Mass Uncertainties

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.

Distribution of Product Value Chain: Do Farmers Receive the Lowest Benefits? The Case of Snubnose Pompano Fishery

Duy Ngoc NGUYEN,Nga Thi NGUYEN,Ngoc Van NGUYEN,Chau Minh HO 한국유통과학회 2024 유통과학연구 Vol.22 No.6

Intra-Organizational Factors Affecting Business Performance: An Empirical Study in Vietnam

Khuong Ngoc MAI,Thao Thi Thanh NGUYEN,Phuong Ngoc Duy NGUYEN,Khoa Tien TRAN 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.10

In the era of industry 4.0 with the robust digital transformation, especially under the trigger of the Covid-19 pandemic, the process of transforming businesses to achieve the desired business performance depends much on the mindset transformation of each member of the organization, beginning with the thoughts of leadership and stakeholders. This study will evaluate the relationship between leadership’s strategic reasoning perspectives on employee engagement or commitment and the company’s reputation, thereby directly or indirectly affecting organizational performance. The study examines data from 382 companies out of 500 samples in typical industries in Vietnam using the exploratory factor analysis (EFA) and partial least squares structural equation modeling (PLS-SEM) techniques. The results show that holistic thinking is closely related to employee retention and corporate reputation, thereby increasing the business outcomes of the organization, whereas there was no evidence to support analytical thinking in this study. As a consequence, transforming the business to achieve the desired business performance is heavily reliant on changing the mindset of each member of the organization, beginning with the top leaders and influencers of the business. This will assist Vietnamese leaders in gaining a comprehensive understanding of corporate governance and controlling the relationships between organizational constructs.

Evaluation of $alpha$-decay Half-life for Measuring Concentration of Radioactive Nuclei

Nguyen Ngoc Duy,Phuong-Thao Ho 한국물리학회 2020 New Physics: Sae Mulli Vol.70 No.5

In this study, we employed the semi-empirical formulae proposed by Viola-Seaborg, Royer, and Poenaru to estimate the -decay half-lives of the radioactive isotopes in the 235;238U chains because they are important for alpha analysis and radioprotection. We found a large uncertainty of about two orders of magnitude, in the experimental data for the half-lives, as evaluated by using each model. The results showed that the current formulae are insufficient for isotopes that undergo a multi-decay mode or -decay probability less than 1:5%. The relations between the estimated halflives and the experimental data in NuDat Database were deduced as linear functions to improve the validity of the semi-empirical models. The large radioactivity uncertainty due to the half-lives calculated by using the three models should be a concerned for the analysis of the radioactive isotopes using alpha spectrometers. On the other hand, an approach for estimating sample sizes based on the -decay half-life in concentration analyses using alpha analysts is proposed for measurements of largely uncertain or unknown half-life isotopes.

Key Determinants of Repurchase Intention toward Organic Cosmetics

Phuong Ngoc Duy NGUYEN,Vinh Tan NGUYEN,Nguyen Ngoc Thao VO 한국유통과학회 2019 The Journal of Asian Finance, Economics and Busine Vol.6 No.3

This paper aims to discover factors and their influences degree to repurchase organic cosmetic in Vietnam. In addition, this research also discloses the main segments that have high demand re-buying intention based on demographic groups of gender, age, income, educational level, job, type of products, and place of production. Twenty-eight scale was designed based on previous studies and adjusted to match the 5-point Likert scale to conduct measurement. By using survey method to test hypotheses and set up conceptual models to collect 295 Vietnamese consumers who have experience in consuming organic cosmetic by explain the results through Smart PLS software. The findings show that there is positive attitude of customers to the intention of acquiring organic cosmetics, green perceived and customer satisfaction. In addition, customer satisfaction, knowledge of products, safety values, and environmental protection consciousness also play important roles to form a positive attitude of customers for products. Moreover, the consciousness of green living of consumers accounts for a high proportion in creating customer satisfaction for organic products. The results show useful information for current premises to determine the factors that influence the decision to repurchase organic cosmetic product, that provide business strategies.

The Impact of Extrinsic Work Factors on Job Satisfaction and Organizational Commitment at Higher Education Institutions in Vietnam

Phuong Ngoc Duy NGUYEN,Linh Le Khanh NGUYEN,Dong Nguyen Thanh LE 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.8

The purpose of this study is to explore the link between job satisfaction and organizational commitment at higher education institutions (HEIs) in emerging countries such as Vietnam and to determine extrinsic work factors that influence job satisfaction. Higher education is critical for socio-economic growth and the overall development of each country. Hence, an understanding of what motivates employees’ actions and attitudes should be obtained before determining the extent of employee satisfaction. The conceptual model was developed by incorporating job satisfaction-related variables, their relationships, and the impact of job satisfaction on organizational commitment. An empirical study was conducted on a study sample of public and private universities, with 316 academics and non-academic employees surveyed. The current study employed the partial least squares structural equation modeling to test the proposed hypotheses. The results reveal a positive and significant relationship between job satisfaction and organizational commitment. The findings confirm that extrinsic work factors (job itself, supervision, working conditions, payment, and reward and recognition) have a positive and significant relationship with job satisfaction. Furthermore, the study indicates that employees at HEIs who have a high level of ability utilization and supervisor support are more likely to be satisfied with their jobs.