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Defence Technology（防务技术） 2024年第5期35卷 168-173页

作者： Martin Macko Xuan Son Bui Kongsathit Phanthavong Duc Hung pham Van Gion Do Van minh Do Jiri Skala University of Defence BrnoCzech Republic Le Quy Don Technical University Ha NoiViet Nam

This paper deals with the collision of sphere shape grenades with sand *** central issue of the article is the establishing of an empirical velocity equation of the grenade while impacting on sand that is used to solve motion equations of the mechanical mechanism inside the impact grenade *** paper focuses on impact velocities that are lower than 5 m s^(-1).An experiment was conducted to study the velocity of the grenade while impacting on dry sand.A high-speed camera video was used to capture the grenade *** grenade velocity in the impact process was generated from these video *** types of fitting curves are used to regress the velocity equation of the grenade while interacting with the sand media and the best-fitting model is *** result shows the regression curve has a high correlation with the experiment data for grenade velocities below 5 m s^(-1).The received regression equation is useful for analyzing the working ability of the inertial mechanism inside the impact grenade or analyzing and choosing the appropriate parameters of each part in the inertial mechanism to meet the required characteristics of the mechanism.

关键词： Dynamic response Impact velocity Impact grenade Low-velocity impact

Dry eye rate and its relationship with disease stage in patients with primary hypertension:a cross-sectional study in Vietnam

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International Journal of Ophthalmology(English edition) 2024年第4期17卷 653-658页

作者： Tran Tat Thang pham Hong Phuong Nguyen Sa Huynh Nguyen Trung Kien NguyenDuy Toan Nguyen Thi Thu ha Le ha Khoa Nguyen Huu Dung Thai Doan Thang Le Viet Thang Nghe An Eye Hospital Nghe An 43000Vietnam Nghe An Friendship General Hospital Nghe An 43000Vietnam Military Hospital 103 Ha Noi 100000Vietnam Vietnam Military Medical University Ha Noi 100000Vietnam hanoi Medical University Ha Noi 100000Vietnam Bạch Mai Hospital Ha Noi 100000Vietnam TTH Vinh General Hospital Nghe An 100000Vietnam

AIM:To determine the dry eye(DE)rate and its relationship with disease stage in patients with primary ***:A cross-sectional study included 432 patients with primary hypertension(with an equal number of patients in each group:144 in stage Ⅰ,Ⅱ,and Ⅲ hypertension)and 144 healthy subjects as a control *** Ocular Surface Disease Index(OSDI)and Schirmer Ⅰ test without anesthetics were conducted on all 576 *** with OSDI scoreshan in the control group(41.7%versus 18.8%;Phan those without DE,P<*** age,a long duration of hypertension,diabetes mellitus,elevated plasma creatinine,and CRP-hs levels were independent factors associated with DE in primary hypertension patients,P<***:DE is a common disorder associated with advanced age,a long duration of hypertension,diabetes mellitus,elevated plasma CRP-hs,and creatinine levels in patients with primary hypertension.

关键词： primary hypertension dry eye stage of hypertension plasma creatinine

EP Aquarii:A New Picture of the Circumstellar Envelope

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Research in Astronomy and Astrophysics 2024年第3期24卷 83-105页

作者： pham T.Nhung Do T.Hoai Pierre Darriulat pham Tuan-Anh pham N.Diep Nguyen B.Ngoc Tran T.Thai Department of Astrophysics Vietnam National Space CenterVietnam Academy of Science and Technology18Hoang Quoc VietNghia DoCau GiayHa Noivietnam

New analyses of earlier ALMA observations of oxygen-rich AGB star EP Aquarii are presented,which complete a previously published analysis and offer a different interpretation of the morpho-kinematics of the circumstellar *** birth of the equatorial density enhancement(EDE)is shown to occur very close to the star where evidence for rotation has been *** to the star and where outflows have been observed:their interaction with the gas of the nascent EDE is seen to play an important role in the development of the wind and the evolution of its radial velocity from 8 to 10 km s^(-1) on the polar symmetry axis to~2 km s^(-1) at the *** implies complex morpho-kinematics:making reliable interpretations with reasonable confidence is *** particular,it questions an earlier interpretation implying the presence of a white dwarf companion orbiting the star at an angular distance of -0″4 from its *** proposes instead an interpretation in terms of a standard mass ejection associated with a shock wave leaving a void of emission in its *** Doppler velocity wings are seen to consist of two components,the upper velocity end of the global wind,reaching above±12 km s^(-1),and an effective line broadening,confined within 200 mas from the center of the star,reaching above±20 km s^(-1) and interpreted as caused by the pattern of shock waves resulting from the interaction between stellar pulsation and convective cell partition.

关键词： stars AGB and post-AGB-(stars) circumstellar matter-radio lines stars

Predicting 3D Radiotherapy Dose-Volume Based on Deep Learning

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Intelligent Automation & Soft Computing 2024年第2期39卷 319-335页

作者： Do Nang Toan Lam Thanh Hien ha Manh Toan Nguyen Trong Vinh pham Trung Hieu Institute of Information Technology Vietnam Academy of Science and TechnologyHanoi10072Vietnam Faculty of Information Technology Lac Hong UniversityBien HoaDong Nai76120Vietnam

Cancer is one of the most dangerous diseaseswith *** of the principal treatments is radiotherapy by using radiation beams to destroy cancer cells and this workflow requires a lot of experience and skill from doctors and *** our study,we focused on the 3D dose prediction problem in radiotherapy by applying the deeplearning approach to computed tomography(CT)images of cancer *** image data has more complex characteristics than normal image data,and this research aims to explore the effectiveness of data preprocessing and augmentation in the context of the 3D dose prediction *** proposed four strategies to clarify our hypothesis in different aspects of applying data preprocessing and *** strategies,we trained our custom convolutional neural network model which has a structure inspired by the U-net,and residual blocks were also applied to the *** output of the network is added with a rectified linear unit(Re-Lu)function for each pixel to ensure there are no negative values,which are absurd with radiation *** experiments were conducted on the dataset of the Open Knowledge-Based Planning Challenge which was collected from head and neck cancer patients treatedwith radiation *** results of four strategies showthat our hypothesis is rational by evaluating metrics in terms of the Dose-score and the Dose-volume histogram score(DVH-score).In the best training cases,the Dose-score is 3.08 and the DVH-score is *** addition,we also conducted a comparison with the results of another study in the same context of using the loss function.

关键词： CT image 3D dose prediction data preprocessing augmentation

Upconversion luminescence of Gd2O3:Er3+and Gd2O3:Er3+/silica nanophosphors fabricated by EDTA combustion method

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Journal of Rare Earths 2019年第11期37卷 1126-1131页

作者： Le Quoc minh Tran Kim Anh Nguyen Duy Hung pham Thi minh Chau Nguyen Thi Quy hai Ho Van Tuyen Vu Thi Thai ha Vu Duc Tu Wieslaw Strek Institute of Theoretical and Applied Research Duy Tan UniversityDa Nang 55000Viet Nam Advanced Institute for Science and Technology Hanoi University of Science and Technology1 Dai Co VietHai Ba TrungHanoiViet Nam Institute of Materials Science Vietnam Academy of Science and Technology18 Hoang Quoc Viet RoadCau Giay DistrictHanoiViet Nam Institute of Low Temperature and Structure Research Polish Academy of Science 2 OkolnaWroclawPoland

Gd2O3:Er^3+nanophosphors were fabricated by the combustion method in presence of Na2 ethylene diamine tetra acetic acid(EDTA-Na2)as fuel at not high temperature(≤350℃)within a very short time of 5 *** added concentration of Er^3+ions in Gd2O3 matrix was changed from 0.5 mol%to 5.0 mol%.The X-ray diffraction pattern of samples indicates the monoclinic structure of Gd2O3:Er^3+.The morphology and chemical composition analysis of the Gd2O3:Er^3+samples are characterized by a field emission scanning electron microscope(FESEM)and a Fourier-transform infrared spectrometer(FTIR).The photoluminescence(PL),photo luminescence excitation(PLE)and upconversion(UC)at room temperature of the prepared materials with different concentrations of Er^3+were *** PL of Gd2O3:Er^3+nanomaterials are shown in visible at 545,594,623,648,688 nm under excitation at 275 *** emission bands from transitions of Er^3+from 2P3/2 to 4F9/2 are observed,UC luminescent spectra of the Gd2O3:Er^3+/silica nanocomposites under 976 nm excitation show the bands at 548 and 670 *** influence of excitation power at 980 nm for transitions were measured and *** results indicate that the upconversion process of Gd2O3:Er^3+/silica is two photons absorption *** low temperature dependence of UC luminescent intensities of the main bands of Gd2O3:Er^3+was investigated towards development of a nanotemperature sensor in the range of 10-300 K.

关键词： Upconversion luminescence Gd2O3:Er3+ Gd2O3:Er3+/silica Nanophosphors EDTA combustion Rare earths

Is convenience really king? Comparative evaluation of catastrophic costs due to tuberculosis in the public and private healthcare sectors of Viet Nam: a longitudinal patient cost study

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贫困所致传染病(英文) 2024年第2期13卷 17-28页

作者： Nguyen Hoa Binh Quang Vo Luan Nguyen Forse Rachel Jeanette Wiemers Anja Maria Christine Huynh Huy Ba Dong Thuy Thi Thu Phan Yen Thi Hoang Creswell Jacob Dang Thi minh ha Nguyen Lan Huu Shedrawy Jad L?nnroth Knut Nguyen Tuan Dinh Van Dinh Luong Annerstedt Kristi Sidney Codlin Andrew James National Lung Hospital Ha Noi Viet Nam Friends for International TB Relief Ha Noi Viet Nam Department of Global Public Health WHO Collaboration Centre On Tuberculosis and Social Medicine Karolinska Institute Stockholm Sweden Stop TB Partnership Geneva Switzerland pham Ngoc Thach Hospital Ho Chi Minh City Viet Nam

Background In Viet Nam, tuberculosis (TB) represents a devastating life-event with an exorbitant price tag, partly due to lost income from daily directly observed therapy in public sector care. Thus, persons with TB may seek care in the private sector for its flexibility, convenience, and privacy. Our study aimed to measure income changes, costs and catastrophic cost incurrence among TB-affected households in the public and private *** Between October 2020 and March 2022, we conducted 110 longitudinal patient cost interviews, among 50 patients privately treated for TB and 60 TB patients treated by the National TB Program (NTP) in ha Noi, hai Phong and Ho Chi minh City, Viet Nam. Using a local adaptation of the WHO TB patient cost survey tool, participants were interviewed during the intensive phase, continuation phase and post-treatment. We compared income levels, direct and indirect treatment costs, catastrophic costs using Wilcoxon rank-sum and chi-squared tests and associated risk factors between the two cohorts using multivariate *** The pre-treatment median monthly household income was significantly higher in the private sector versus NTP cohort (USD 868 vs USD 578;P=0.010). However, private sector treatment was also significantly costlier (USD 2075 vs USD 1313;P=0.005), driven by direct medical costs which were 4.6 times higher than costs reported by NTP participants (USD 754 vs USD 164;P<0.001). This resulted in no significant difference in catastrophic costs between the two cohorts (Private: 55% vs NTP: 52%;P=0.675). Factors associated with catastrophic cost included being a single-person household [adjusted odds ratio [(aOR=13.71; 95% confidence interval (CI): 1.36–138.14;P=0.026], unemployment during treatment (aOR=10.86; 95%CI: 2.64–44.60;P<0.001) and experiencing TB-related stigma (aOR=37.90; 95%CI: 1.72–831.73;P=0.021).Conclusions Persons with TB in Viet Nam face similarly high risk of catastrophic costs whether treated in the

关键词： Tuberculosis Patient cost Catastrophic cost Private sector Comparative analysis Viet Nam

Synthesis and characterization of NaYF4:Yb3+,Er3+@silica-N=folic acid nanocomplex for bioimaginable detecting MCF-7 breast cancer cells

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Journal of Rare Earths 2019年第11期37卷 1183-1187页

作者： ha Thi Phuong Tran Thu Huong Le Thi Vinh Hoang Thi Khuyen Do Thi Thao Nguyen Thanh Huong pham Thi Lien Le Quoc minh Institute of Materials Science Vietnam Academy of Science and Technology18 Hoang Quoc VietCau GiayHanoiViet Nam Graduate University of Science and Technology-Vietnam Academy of Science and Technology 18 Hoang Quoc VietCau GiayHanoiViet Nam Department of Chemistry Hanoi Medical University1-Ton That TungDong DaHanoiViet Nam Department of Chemistry Hanoi University of Mining and Geology18-Pho LienBac Tu LiemHanoiViet Nam Institute of Biotechnology Vietnam Academy of Science and Technology18-Hoang Quoc VietCau GiayHanoiViet Nam Duy Tan University K7/25 Quang TrungDa NangViet Nam

Upconversion nanophosphors are new promising nanomaterials to be used as biolabels for detection and imaging of cancer *** nanophosphors absorb long-wavelength excitation radiation in the infrared or near infrared region and emit shorter wavelength,higher energy radiation from ultraviolet to *** this paper,we studied the hydrothermal method and optical properties of the functionalized NaYF4:Yb^3+,Er^3+for biomedical *** synthesis,these NaYF4:Yb^3+,Er^3+nanophosphors were functionalized with aminosilanes and folic *** acid binds to the folate receptor on the surface of MCF-7 breast cancer cells and this binding promotes internalization of the nanophosphors via *** sizes of the functionalized NaYF4:Yb^3+,Er^3+@silica-N=FA(folic acid)nanophosphors can be controlled with length of the rod about 300-800 nm and diameter of the rod about 100-200 *** structure of NaYF4:Yb^3+,Er^3+is in hexagonal crystal *** photo luminescence(PL)spectra of the functionalized NaYF4:Yb^3+,Er^3+@silica-N=FA nanophosphors were *** nanophosphors emit in red color with the strongest band at 650 nm under 980 nm *** result can provide NaYF4:Er^3+,Yb^3+@silica-N=FA complex for developing fluorescence label and image tool in cancer biology and medicine.

关键词： Upconversion luminescence NaYF4:Yb^3+,Er^3+ Nanophosphors Bioimaging Cancer cell Rare earths

A Data Collection on Secondary School Students’STEM Performance and Reading Practices in an Emerging Country

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Data Intelligence 2021年第2期3卷 336-356页

作者： Quan-Hoang Vuong Viet-Phuong La Manh-Toan Ho Thanh-hang pham Thu-Trang Vuong ha-My Vuong minh-Hoang Nguyen Centre for Interdisciplinary Social Research Phenikaa UniversityYen Nghia WardHa Dong DistrictHanoi 100803Vietnam A.I.for Social Data Lab Vuong&AssociatesDong Da DistrictHanoi 100000Vietnam School of Business and Management RMIT Vietnam UniversityHanoi 100000Vietnam

Science,technology,engineering,and mathematics(STEM)education has become a critical factor in promoting sustainable ***,book reading is still an essential method for cognitive development and knowledge *** developing countries where STEM teaching and learning resources are limited,book reading is an important educational tool to promote ***,public data sets about STEM education and book reading behaviors in emerging countries are *** article,therefore,aims to present a data set of 4,966 secondary school students from a school-based data collection in *** data set comprises of five major categories:1)students’personal information(including STEM performance),2)family-related information,3)book reading preferences,4)book reading frequency/habits,and 5)classroom *** introducing the designing principles,the data collection method,and the variables in the data set,we aim to provide researchers,policymakers,and educators with well-validated resources and guidelines to conduct low-cost research,pedagogical programs in emerging countries.

关键词： STEM education Socio-economic status Book reading Emerging country Students

Hybrid model to optimize object-based land cover classification by meta-heuristic algorithm:an example for supporting urban management in ha Noi,Viet Nam

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International Journal of Digital Earth 2019年第10期12卷 1118-1132页

作者： Quang-Thanh Bui Manh pham Van Nguyen Thi Thuy hang Quoc-Huy Nguyen Nguyen Xuan Linh pham minh hai Tran Anh Tuan pham Van Cu Center for Applied Research in Remote sensing and GIS(CARGIS) VNU University of ScienceHa NoiViet Nam VNU University of Science Ha NoiViet Nam Vietnam Institute of Geodesy and Cartography Ha NoiViet Nam Ministry of Education and Training Ha NoiViet Nam

This study proposed a novel object-based hybrid classification model named GMNN that combines Grasshopper Optimization Algorithm(GOA)and the multiple-class Neural network(MNN)for urban pattern detection in hanoi,*** bands of SPOT 7 image and derivable NDVI,NDWI were used to generate image segments with associated attributes by PCI Geomatics *** segments were classified into four urban surface types(namely water,impervious surface,vegetation and bare soil)by the proposed ***,three training and validation datasets of different sizes were used to verify the robustness of this *** all tests,the overall accuracies of the classification were approximately 87%,and the Area under Receiver Operating Characteristic curves for each land cover type was ***,the performance of this model was examined by comparing several statistical indicators with common benchmark *** results showed that GMNN out-performed established methods in all comparable *** results suggested that our hybrid model was successfully deployed in the study area and could be used as an alternative classification method for urban land cover *** a broader sense,classification methods will be enriched with the active and fast-growing contribution of metaheuristic algorithms.

关键词： Urban remote sensing object-based classification neural network grasshopper optimization algorithm