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Calibration of a neutron dose rate meter in various neutron standard fields

Nuclear Science and Techniques 2020年第6期31卷 75-82页

作者： Tuan Khai Nguyen Hoai-Nam Tran Quynh ngoc Nguyen Thi My Linh Dang Van Loat Bui Thiansin Liamsuwan ngoc-thiem le Vietnam Agency for Radiation and Nuclear Safety 113 Tran Duy HungHanoi 100000Vietnam Institute of Fundamental and Applied Sciences Duy Tan UniversityHo Chi Minh 700000Vietnam Faculty of Natural Sciences Duy Tan University3 Quang TrungDa Nang 550000Vietnam Institute for Nuclear Science and Technology VINATOM179 Hoang Quoc VietHanoi 100000Vietnam Faculty of Physics VNU University of Science334 Nguyen TraiHanoi 100000Vietnam Nuclear Research and Development Division Thailand Institute of Nuclear TechnologyOngkharakNakorn NayokThailand 7 Faculty of Medicine and Public HealthHRH Princess Chulabhorn College of Medical ScienceChulabhorn Royal AcademyBangkokThailand

This paper presents the calibration of a neutron dose rate meter and the evaluation of its calibration factors(CFs)in several neutron standard fields(i.e.,two standard fields with bare sources of252Cf and241Am-Be,and five simulated workplace fields with241Am-Be moderated sources).The calibration in standard fields with bare sources was conducted by following the recommendations of the ISO 8529 *** measured total neutron ambient dose equivalent rates,denoted as H*(10)tot,were analyzed to obtain direct components,denoted as H*(10)dir,using a reduced fitting *** CF was then calculated as the ratio between the conventional true value of the neutron ambient dose equivalent rate in a free field,denoted as H*(10)FF,and the value of H*(10)*** contrast,in the simulated workplace neutron fields,the calibration of the neutron dose rate meter was conducted by following the ISO 12789 *** CF was calculated as the ratio between the values of H*(10)totmeasured by a standard instrument(i.e.,Bonner sphere spectrometer)and the neutron dose rate *** CF values were obtained in the range of 0.88–*** standard uncertainties(k=1)of the CFs were determined to be in the range of approximately 6.6–13.1%.

关键词： Neutron standard fields Neutron dose rate meter Calibration factor 252Cf source 241AmBe source

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Evaluation of the calibration factors of neutron dose rate meters in a 241Am–Be neutron field

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Nuclear Science and Techniques 2019年第9期30卷 18-23页

作者： thiem ngoc le Sy Minh Tuan Hoang Quynh ngoc Nguyen Hoai-Nam Tran Institute for Nuclear Science and Technology VINATOM 179 Hoang Quoc Viet Hanoi Vietnam Institute of Fundamental and Applied Sciences Duy Tan University Ho Chi Minh City Vietnam

Calibrations were performed for three types of neutron ambient dose equivalent rate meters, i.e., Aloka TPS-451C (Hitachi), KSAR1U.06 (Baltic Scientific Instruments), and Model 12-4 (Ludlum), using a standard field of a 241Am–Be source. The measured total neutron ambient dose equivalent rates, H*(10)' tot, were analyzed to obtain the direct neutron ambient dose equivalent rates, H*(10)' dir, using the ISO 8529-2-recommended generalized- fit method, semiempirical fit method, and reducedfitting method (RFM) fit methods. The calibration factor (CF), defined as the ratio between the conventional true value of the neutron ambient dose equivalent rates in a free field, H*(10)' FF, and H*(10)' dir, was evaluated as one of the important characteristics of the neutron meters in the present work. The fitting results show that the H*(10)' dir values of the meters are in good agreement within the theoretical data within 4%. The averaged CFs of the three neutron meters were evaluated as 0:99 ± 0:01, 1:00 ± 0.03;and 0:99 ± 0:08, respectively. The largest standard uncertainty of these values was determined to be approximately 18.47%(k =1). The standard uncertainty of the CFs obtained using the RFM method was less than 4.23%(k=1), which is the smallest uncertainty among the three methods.

关键词： Neutron meter Calibration factor ^241 Am–Be source

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Prevalence and risk factors associated with long COVID symptoms in children and adolescents in a southern province of Vietnam

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Asian Pacific Journal of Tropical Medicine 2024年第3期17卷 119-128,I0001,I0002页

作者： Huynh ngoc Linh Nguyen The Tan le Thi Minh Thu Nguyen Tu Loan Nguyen Thi To Uyen le Thanh Thao Trang Truong Thanh Nam Doan Hoang Phu Faculty of Medicine Ca Mau Medical CollegeCa Mau 98000Vietnam Ca Mau Obstetrics and Pediatrics Hospital Ca Mau 98000Vietnam Faculty of Basic Science and Public Health Dong Thap Medical CollegeDong Thap 81000Vietnam Graduate University of Sciences and Technology Vietnam Academy of Science and TechnologyHa Noi 10000Vietnam Community Public Health Research Program School of Public HealthWalailak UniversityNakhon Si Thammarat 80160Thailand Faculty Public Health Can Tho University of Medicine and PharmacyCan Tho City 94000Vietnam Doctoral Program in Health Sciences College of Graduate StudiesWalailak UniversityNakhon Si Thammarat 80160Thailand

Objective:To investigate the prevalence and risk factors associated with long COVID symptoms among children and adolescents who have recovered from ***:This study applied a cross-sectional approach within community settings in a southern province of Vietnam.A structured questionnaire featuring socio-demographic information and common long COVID symptoms was *** correlation coefficients assessed associations among pairs of long COVID ***,multivariable logistic regression models were performed to investigate the risk factors of long COVID in recovered COVID-19 children and ***:Among 422 participants,39.3%reported long COVID symptoms,with a prevalence of 45.2%(SD=0.5)in children and 22.2%(SD=0.4)in *** symptoms reported were cough 34.6%(SD=0.5),fatigue 20.6%(SD=0.4),shortness of breath 10.9%(SD=0.3),and lack of appetite 6.6%(SD=0.3).Concerning risk factors of long COVID,a higher risk was observed among demographic groups,including girls(OR 1.25,95%CI 1.15-1.37;Plescents(OR 1.24,95%CI 1.12-1.37;Ple dose(OR 1.35,95%CI 1.10-1.64;P=0.004)compared to those who have received two ***,patients with a COVID-19 treatment duration exceeding two weeks also had a higher risk of long COVID(OR 1.32,95%CI 1.09-1.60;P=0.003)than those who recovered less than seven ***:The insights from this study provide crucial guidance for predicting the factors associated with the occurrence of long COVID in pediatric patients,contributing to strategic interventions aimed at mitigating the long COVID risks among children and adolescents in Vietnam.

关键词： Long COVID Prevalence Risk factors Children Adolescent Vietnam

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Random vibration analysis of FGM plates subjected to moving load using a refined stochastic finite element method

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Defence Technology（防务技术） 2024年第4期34卷 42-56页

作者： ngoc-Tu Do Trung Thanh Tran Faculty of Mechanical Engineering Hanoi University of IndustryHanoiViet Nam Faculty of Mechanical Engineering Le Quy Don Technical UniversityHanoiViet Nam

The article introduces a finite element procedure using the bilinear quadrilateral element or four-node rectangular element(namely Q4 element) based on a refined first-order shear deformation theory(rFSDT) and Monte Carlo simulation(MCS), so-called refined stochastic finite element method to investigate the random vibration of functionally graded material(FGM) plates subjected to the moving *** advantage of the proposed method is to use r-FSDT to improve the accuracy of classical FSDT, satisfy the stress-free condition at the plate boundaries, and combine with MCS to analyze the vibration of the FGM plate when the parameter inputs are random quantities following a normal distribution. The obtained results show that the distribution characteristics of the vibration response of the FGM plate depend on the standard deviation of the input parameters and the velocity of the moving ***, the numerical results in this study are expected to contribute to improving the understanding of FGM plates subjected to moving loads with uncertain input parameters.

关键词： FGM Moving load R-FSDT Q4 element Monte Carlo simulation Random vibration

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Exploring the Interplay between Job Stress,Work Performance,and Attitudes toward Professional Psychological Help among Employees

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International Journal of Mental Health Promotion 2024年第7期26卷 531-545页

作者： Cong Minh le Son Van Huynh Ky Luu Quynh-Nhi ngoc Ho Van Thi le Nguyen Vinh-Long Tran-Chi Center for Mental Health Research and Support University of Social Sciences and HumanitiesVietnam National University Ho Chi Minh CityHo Chi Minh City700000Vietnam Faculty of Psychology Ho Chi Minh City University of EducationHo Chi Minh City700000Vietnam Faculty of Tourism College of BusinessUniversity of Economics Ho Chi Minh CityHo Chi Minh City700000Vietnam Scientific Management Department Dong A UniversityDa Nang500000Vietnam

Objective:This study explores the interplay between job stress,job-related factors,work performance,and attitudes toward seeking professional psychological help among Vietnamese ***:A total of 374 employees in Vietnam were surveyed using random sampling and an online questionnaire from November 07 to November 28,*** data and self-reported from three scales:The New Job Stress Scale(NJSS),Work Performance(WP),and Attitudes Toward Seeking Professional Psychological Help(ATSPPH_SF)were ***:Significant variations were found across several variables,including forms of work,operating hours,education levels,monthly income,numbers of daily working hours,and the presence of a psychological counseling department within the *** analysis has highlighted direct relationships between key latent *** who were more open to seeking professional help tended to report higher levels of job *** negative relationship was found between job stress and attitudes toward seeking professional ***,work effort was positively associated with work *** analyses revealed the influence of co-worker support on role expectation conflict and work effort,role expectation conflict and work-life balance,as well as interactions between role expectation conflict and attitudes needed toward seeking professional *** analyses showed that work effort mediated relationships between openness to seeking professional help,co-worker support,work-life balance,role expectation conflict,and work *** toward seeking professional help also mediated relationships between work-life balance,job stress,and work ***:The study highlights the complex dynamics surrounding job stress,job-related factors,work performance,and attitudes toward seeking professional psychological help among Vietnamese *** highlights the importance of addressing help-seeking barriers,promoting work engagement

关键词： Stress co-worker support work-life balance role expectation conﬂict professional psychological help-seeking

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Prevalence, risk factors, and BRAF mutation of colorectal sessile serrated lesions among Vietnamese patients

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World Journal of Clinical Oncology 2024年第2期15卷 290-301页

作者： Nhu Thi Hanh Vu Huy Minh le Diem Thi-ngoc Vo Hoang Anh Vu Nhan Quang le Dung Dang Quy Ho Duc Trong Quach Department of Internal Medicine University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh 700000Viet Nam GI Endoscopy Department University Medical Center at Ho Chi Minh CityHo Chi Minh 700000Viet Nam Department of Histology-Embryology and Pathology University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh 700000Viet Nam Center for Molecular Biomedicine University of Medicine and Pharmacy at Ho Chi Minh CityHo Chi Minh 700000Viet Nam Department of Endoscopy Cho Ray HospitalHo Chi Minh 700000Viet Nam

BACKGROUND Sessile serrated lesions(SSLs)are considered precancerous colorectal lesions that should be detected and removed to prevent colorectal *** studies in Vietnam mainly investigated the adenoma pathway,with limited data on the serrated *** To evaluate the prevalence,risk factors,and BRAF mutations of SSLs in the Vietnamese *** This is a cross-sectional study conducted on patients with lower gastrointestinal symptoms who underwent colonoscopy at a tertiary hospital in *** were diagnosed on histopathology according to the 2019 World Health Organi-zation *** mutation analysis was performed using the Sanger DNA sequencing *** multivariate logistic regression model was used to determine SSL-associated *** There were 2489 patients,with a mean age of 52.1±13.1 and a female-to-male ratio of 1:*** prevalence of SSLs was 4.2%[95%confidence interval(CI):3.5-5.1].In the multivariate analysis,factors significantly associated with SSLs were age≥40[odds ratio(OR):3.303;95%CI:1.607-6.790],male sex(OR:2.032;95%CI:1.204-3.429),diabetes mellitus(OR:2.721;95%CI:1.551-4.772),and hypertension(OR:1.650,95%CI:1.045-2.605).The rate of BRAF mutations in SSLs was 35.5%.CONCLUSION The prevalence of SSLs was 4.2%.BRAF mutations were present in one-third of *** risk factors for SSLs included age≥40,male sex,diabetes mellitus,and hypertension.

关键词： Colorectal cancer Sessile serrated lesion BRAF mutation Risk factors Diabetes mellitus Hypertension

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EXISTENCE AND STABILITY OF PERIODIC AND ALMOST PERIODIC SOLUTIONS TO THE BOUSSINESQ SYSTEM IN UNBOUNDED DOMAINS

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Acta Mathematica Scientia 2022年第5期42卷 1875-1901页

作者： Thieu Huy NGUYEN Truong Xuan PHAM Thi ngoc Ha VU The Sac le School of Applied Mathematics and Informatics Hanoi University of Science and Technology Vien Toan ung dung va Tin hocDai hoc Bach khoa Hanoi 1DaiCoVietHanoiVietnam Department of Mathematics Faculty of Information TechnologyThuyloi university Khoa Cong nghe Thong tinBo mon ToanDai hoc Thuy loi175 Tay SonDong DaHa NoiViet Nam Thuyloi University Dai hoc Thuy Loi175 Tay SonDong DaHanoiViet Nam

In this paper we investigate the existence and stability of periodic solutions(on a half-line R_(+))and almost periodic solutions on the whole line time-axis R to the Boussinesq system on several classes of unbounded domains of R^(n) in the framework of interpolation *** the linear Boussinesq system we combine the L^(p)—L^(q)-smoothing estimates and interpolation functors to prove the existence of bounded mild ***,we prove the existence of periodic solutions by invoking Massera’s *** also prove the existence of almost periodic *** we use the results of the linear Boussinesq system to establish the existence,uniqueness and stability of the small periodic and almost periodic solutions to the Boussinesq system using fixed point arguments and interpolation *** results cover and extend the previous ones obtained in[13,34,38].

关键词： Boussinesq systems periodic solutions almost periodic solutions unbounded domains smoothing estimates dual estimates interpolation spaces stability

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Myo-inositol versus metformin effects on clinical features, endocrine and metabolic profiles in infertile women with polycystic ovary syndrome: A randomized controlled trial

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Asian pacific Journal of Reproduction 2023年第6期12卷 256-265页

作者： Nguyen Sa Viet le Minh Tam le Thanh ngoc Cao Center for OBGYN Hue Central Hospital16 Le Loi StreetHueVietnam Center for Reproductive Endocrinology and Infertility Hue University of Medicine and PharmacyHue University06 Ngo Quyen StreetHueVietnam

Objective:To compare the effectiveness of inositol and metformin on the clinical characteristics,and endocrine and metabolic profiles of infertile polycystic ovarian syndrome(PCOS)women from ***:From June 2018 to August 2022,a randomized trial was undertaken at the Hue Center for Endocrinology and Reproduction on infertile women aged 18 to 40 years with polycystic ovarian *** clinical,endocrine,and metabolic features of these individuals were assessed before and after 3 months of treatment with 2 g of inositol or 1700 mg of metformin per *** pregnancy rates,adverse effects,and tolerance of inositol were ***:The study included 171 infertile PCOS women who were eligible to participate and took part in the baseline assessment,of whom 132 women participated in data analysis after 3 *** metformin treatment,42.1%of women with oligomenorrhea experienced regular *** significantly lowered body mass index(BMI),waist circumference and testosterone levels,but had no effect on other clinical characteristics,endocrine profiles,or metabolic profiles.29.2%Of women reported experiencing side effects.21%Of them attained pregnancy,which resulted in 17.1%of live *** the inositol group,the rate of regular cycle increased by 18.2%and the total testosterone concentration significantly *** overweight/obese women with PCOS,inositol significantly decreased weight,BMI,waist and hip circumferences(Plerated inositol and continued treatment.18.9%Of them became pregnant,leading to 17%of live ***:Metformin and inositol can improve weight and waist circumference in overweight/obese infertile women with *** is associated with a higher rate of regular menstruation,whereas inositol is associated with a lower rate of adverse *** spontaneous conception,clinical pregnancy,and live birth rates between two groups are comparable.

关键词： Polycystic ovarian syndrome Inositol Metformin Endocrine Metabolic Menstrual cycle Pregnancy

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Rapid and efficient characterization of cervical collagen orientation using linearly polarized colposcopic images

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Journal of Innovative Optical Health Sciences 2023年第5期16卷 21-31页

作者： Cat Phan ngoc Khuong Dung Nguyen Huu Quang Hai Pham Thanh Long Nguyen Quynh Nguyen ngoc Duc le Huynh Tien Tran Van Tu Ly Anh Department of Applied Physics Ho Chi Minh City University of Technology 268 Ly Thuong Kiet Street District 10 Ho Chi Minh City 700000Vietnam Quality Management Department Tu Du Hospital 284 Cong QuynhDistrict 1 Ho Chi Minh City 700000Vietnam Department of Biomedical Engineering Nguyen Tat Thanh University 300A Nguyen Tat Thanh District 4Ho Chi Minh City 700000Vietnam Faculty of Science and Technology Jean Monnet University 11 Rue du Docteur Annino Saint Etienne 42000France

Collagen provides tissue strength and structural *** fication of the orientated dispersion of collagen fibers is an important factor when studying the mechanical properties of the *** this study,for the first time,a new method for rapid characterization of the collagen fiber orientations of the cervix using linearly polarized light colposcopy is presented.A total of 24 colposcopic images were captured using a cross-polarized imaging system with white leD light *** the preprocessing stage,the Red channel of the RGB image was chosen,which contains no information of the blood vessels because of the low-absorption of blood cells in the red ***,which is an ImageJ plug-in,was used to estimate the local orientation of the collagen *** result shows that in the nonpregnant cervix,the middle zone(Zone 2)has circumferentially aligned collagen fibers while the inner zone(Zone 1)has randomly *** collagen fiber dispersion in Zone 2 is much smaller than that in Zone 1 at all four quadrants region(anterior,posterior,left,and right quadrant).This new analysis technique could potentially combine with diagnostic tools to provide a quantitative platform of collagen fibers in the clinic.

关键词： Cervix collagen fibers collagen orientation coherency cross-polarized imaging colposcopy

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Building 3D CityGML models of mining industrial structures using integrated UAV and TLS point clouds

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International Journal of Coal Science & Technology 2023年第5期10卷 158-177页

作者： Canh le Van Cuong Xuan Cao Anh ngoc Nguyen Chung Van Pham Long Quoc Nguyen Department of Mine Surveying Hanoi University of Mining and GeologyHanoiVietnam Viettel Group Viettel Cyberspace CenterHanoiVietnam

Mining industrial areas with anthropogenic engineering structures are one of the most distinctive features of the real world.3D models of the real world have been increasingly popular with numerous applications,such as digital twins and smart factory *** this study,3D models of mining engineering structures were built based on the CityGML *** collecting spatial data,the two most popular geospatial technologies,namely UAV-SfM and TLS were *** accuracy of the UAV survey was at the centimeter level,and it satisfied the absolute positional accuracy requirement of creat-ing all levels of detail(LoD)according to the CityGML ***,the UAV-SfM point cloud dataset was used to build LoD 2 *** addition,the comparison between the UAV-SfM and TLS sub-clouds of facades and roofs indicates that the UAV-SfM and TLS point clouds of these objects are highly consistent,therefore,point clouds with a higher level of detail and accuracy provided by the integration of UAV-SfM and TLS were used to build LoD 3 *** resulting 3D CityGML models include 39 buildings at LoD 2,and two mine shafts with hoistrooms,headframes,and sheave wheels at LoD3.

关键词： 3D modelling CityGML-Mining industry UAV Terrestrial laser scanning Point cloud

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