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World Journal of Engineering and Technology 2015年第4期3卷 311-319页

作者： hong-anh vu Jianqiong Wang Lianxing Min Thihong-Nhung Nguyen School of Economics and Management Southwest Jiaotong University Chengdu China School of Management Chengdu University of Traditional Chinese Medicine Chengdu China

Vietnam has become a major market for construction enterprises from East Asian countries, especially from China, to participate in international project contracting, but serious schedule delays have important adverse effects on local government and foreign investment companies. Based on international engineering contracting mode of Vietnam highway BOT construction projects, we discussed the drive financial factors of schedule delays, using the methods of exploratory factor analysis and questionnaire survey, and evaluated the effects of various factors which are through regression analysis. The empirical results show that the five categories of financial factors, including the policy change, slow payment, financial mismanagement, financial market changes and lack of fiscal, have significant effects on schedule delay. Furtherly, we suggested that strengthening policy research and improving financial management ability should be used to reduce the influence of relevant financial factors on schedule delay, to improve the profitability of international businesses and the motivation of foreign enterprises to participate in Vietnam highway project.

关键词： Scheduling Risk Management Exploratory Analysis Project Delay Fiscal Factors Risk Evaluation

Research on Cost Overrun Risk of Construction Phase of Vietnam Highway International Contracting Project

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Engineering（科研） 2016年第3期8卷 86-98页

作者： hong anh vu Jianqiong Wang Lianxing Min Sy Hung Mai hong Phong Nguyen School of Economics and Management Southwest Jiaotong University Chengdu China School of Management Chengdu University of Traditional Chinese Medicine Chengdu China School of Railway Section University of Transport and Communications Hanoi Vietnam

Recently, the highway construction projects increase rapidly in Vietnam and most of them are international contracting projects. It results serious negative influence on the local government and enterprises that the common cost overrun of projects, and the risk factors of it is different in the different countries, different stages and projects types. So in this paper, we generate an evaluation index system of highway construction projects cost overrun risk in Vietnam in the perspective of different project participants, and also evaluate the effects of these factors in method of regression analysis. The empirical results confirmed 7 main factors that have aggravated cost overrun risk in construction stages, e.g. survey and design scheme risk. In final, the corresponding suggestions are proposed to reduce the project cost overrun risk.

关键词： Highway Construction Cost Overrun Risk Management Vietnam

Transient response of doubly-curved bio-inspired composite shells resting on viscoelastic foundation subject to blast load using improved first-order shear theory and isogeometric approach

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Defence Technology（防务技术） 2024年第8期38卷 171-193页

作者： Thuy Tran Thi Thu Tu Nguyen anh Hue Nguyen Thi hong Nguyen Thi School of Mechanical and Automotive Engineering Hanoi University of IndustryHanoiViet Nam Faculty of Technical Fundamental University of Transport TechnologyHanoiViet Nam Faculty of Mechanical Engineering Thuyloi University175 Tay SonDong DaHanoiViet Nam

Investigating natural-inspired applications is a perennially appealing subject for scientists. The current increase in the speed of natural-origin structure growth may be linked to their superior mechanical properties and environmental resilience. Biological composite structures with helicoidal schemes and designs have remarkable capacities to absorb impact energy and withstand damage. However, there is a dearth of extensive study on the influence of fiber redirection and reorientation inside the matrix of a helicoid structure on its mechanical performance and reactivity. The present study aimed to explore the static and transient responses of a bio-inspired helicoid laminated composite(B-iHLC) shell under the influence of an explosive load using an isomorphic method. The structural integrity of the shell is maintained by a viscoelastic basis known as the Pasternak foundation, which encompasses two coefficients of stiffness and one coefficient of damping. The equilibrium equations governing shell dynamics are obtained by using Hamilton's principle and including the modified first-order shear theory,therefore obviating the need to employ a shear correction factor. The paper's model and approach are validated by doing numerical comparisons with respected publications. The findings of this study may be used in the construction of military and civilian infrastructure in situations when the structure is subjected to severe stresses that might potentially result in catastrophic collapse. The findings of this paper serve as the foundation for several other issues, including geometric optimization and the dynamic response of similar mechanical structures.

关键词： Blast load Modified first-order shear theory Biological composite structures

Generating highly active oxide-phosphide heterostructure through interfacial engineering to break the energy scaling relation toward urea-assisted natural seawater electrolysis

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Journal of Energy Chemistry 2024年第10期97卷 687-699页

作者： Ngoc Quang Tran Nam Hoang vu Jianmin Yu Khanh Vy Pham Nguyen Thuy Tien Nguyen Tran Thuy-Kieu Truong Lishan Peng Thi anh Le Yoshiyuki Kawazoe Center for Innovative Materials and Architectures Vietnam National University Faculty of Materials Science and Technology University of Science Key Laboratory of Rare Earths Ganjiang Innovation Academy Chinese Academy of Sciences Department of Mechanical Engineering Hanbat National University (HBNU) School of Chemical Engineering-Hanoi University of Science and Technology New Industry Creation Hatchery Center Tohoku University

Urea-assisted natural seawater electrolysis is an emerging technology that is effective for grid-scale carbon-neutral hydrogen mass production yet *** scaling relations is an effective strategy to break through the bottleneck of natural seawater ***,by DFT calculation,we demonstrated that the interface boundaries between Ni2P and MoO2play an essential role in the selfrelaxation of the Ni-O interfacial bond,effectively modulating a coordination number of intermediates to control independently their adsorption-free energy,thus circumventing the adsorption-energy scaling *** this conceptual model,a well-defined 3D F-doped Ni2P-MoO2heterostructure microrod array was rationally designed via an interfacial engineering strategy toward urea-assisted natural seawater *** a result,the F-Ni2P-MoO2exhibits eminently active and durable bifunctional catalysts for both HER and OER in acid,alkaline,and alkaline sea water-based *** in-situ analysis,we found that a thin amorphous layer of NiOOH,which is evolved from the Ni2P during anodic reaction,is real catalytic active sites for the OER and UOR ***,such electrode-assembled urea-assisted natural seawater electrolyzer requires low voltages of 1.29 and 1.75 V to drive 10 and600 mA cm-2and demonstrates superior durability by operating continuously for 100 h at 100 mA cm-2,beyond commercial Pt/C || RuO2and most previous reports.

关键词： Break scaling relationships Doping Interfacial engineering Natural seawater splitting Urea electrolysis

Optimal Scheduling of Multiple Rail Cranes in Rail Stations with Interference Crane Areas

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Intelligent Automation & Soft Computing 2024年第1期39卷 15-31页

作者： Nguyen vu anh Duy Nguyen Le Thai Nguyen Huu Tho Faculty of Engineering and Technology Nguyen Tat Thanh UniversityHo Chi Minh City700000Vietnam

In this paper,we consider a multi-crane scheduling problem in rail stations because their operations directly influence the throughput of the rail *** particular,the job is not only assigned to cranes but also the job sequencing is implemented for each crane to minimize the makespan of cranes.A dual cycle of cranes is used to minimize the number of working cycles of *** rail crane scheduling problems in this study are based on the movement of *** consider not only the gantry moves,but also the trolley moves as well as the rehandle cases are also included.A mathematical model of multi-crane scheduling is *** traditional and parallel simulated annealing(SA)are adapted to determine the optimal scheduling *** examples are conducted to evaluate the applicability of the proposed *** of the proposed parallel SA is done by comparing it to existing previous *** of numerical computation highlighted that the parallel SA algorithm outperformed the SA and gave better solutions than other considered algorithms.

关键词： Multi-crane scheduling logistics containers makespan rail stations

Autohydrolysis treatment of bamboo and potassium oxalate(K_(2)C_(2)O_(4))activation of bamboo product for CO_(2) capture utilization

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Frontiers of Chemical Science and Engineering 2024年第4期18卷 63-72页

作者： Dang Duc Viet Doan Thi Thao Khuong Duy anh Toshiki Tsubota Department of Materials Science Faculty of EngineeringKyushu Institute of TechnologyFukuoka 804-8550Japan Vietnamese Academy of Forest Sciences Hanoi 10000Vietnam Collaborative Research Centre for Green Materials on Environmental Technology Kyushu Institute of TechnologyFukuoka 808-0196Japan

Typically,the hydroxide agents,such as sodium hydroxide and potassium hydroxide,which have corrosive properties,are used in the carbon activation *** this study,potassium oxalate(K_(2)C_(2)O_(4)),a less toxic and non-corrosive activating reagent,was used to synthesize activated carbon from the solid residue after autohydrolysis *** effect of the autohydrolysis treatment and the ratio of the K_(2)C_(2)O_(4)/solid residue are presented in this ***,the comparison between the activated carbon from bamboo and biochar from the solid residue are also *** resulting activated carbon from the solid residue exhibited a high surface area of up to 1432 m^(2)·g^(-1) and a total pore volume of up to 0.88 cm^(3)·g^(-1).The autohydrolysis treatment enhanced the microporosity properties compared to those without pretreatment of the activated *** microporosity of the activated carbon from the solid residue was dominated by the pore width at 0.7 nm,which is excellent for CO_(2) *** 25℃ and 1.013×10^(5) Pa,the CO_(2) captured reached up to 4.1 mmol·g^(-1).On the other hand,the ratio between K_(2)C_(2)O_(4) and the solid residue has not played a critical role in determining the porosity *** ratio of the K_(2)C_(2)O_(4)/solid residue of 2 could help the carbon material reach a highly microporous textural property that produces a high carbon capture *** finding proved the benefit of using the solid residue from the autohydrolysis treatment as a precursor material and offering a more friendly and sustainable activation carbon process.

关键词： activated carbon bamboo biochar CO_(2)capture potassium oxalate

Modelling the viscoplastic behaviour of Callovo-Oxfordian claystone with consideration of damage effect

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 303-316页

作者： Hao Wang Yu-Jun Cui Minh Ngoc vu Jean Talandier Ecole des Ponts ParisTech Laboratoire Navier/CERMES6 et 8 avenue Blaise PascalMarne La Vallée cedex 277455France Andra R&D DepartmentChâtenay-Malabry92290France

In order to evaluate the performance of deep geological disposal of radioactive waste,an underground research laboratory(URL)was constructed by Andra in the Callovo-Oxfordian(COx)claystone formation at the Meuse/Haute-Marne(MHM).The construction of URL induced the excavation damage of host formations,and the ventilation in the galleries desaturated the host formation close to the gallery ***,it is expected that the mechanical behaviour of COx claystone is *** study presents a constitutive model developed to describe the viscoplastic behaviour of unsaturated and damaged COx *** this model,the unsaturation effect is considered by adopting the Bishop effective stress and the van Genuchten(VG)water retention *** terms of the viscoplastic behaviour,the nonstationary flow surface(NSFS)theory for unsaturated soils is used with consideration of the coupled effects of strain rate and suction on the yield stress.A progressive hardening law is ***,a non-associated flow rule is used,which is similar to that in Barcelona basic model(BBM).In addition,to describe the damage effect induced by suction change and viscoplastic loading,a damage function is defined based on the crack volume *** damage function contains two variables:unsaturated effective stress and viscoplastic volumetric strain,with the related parameters determined based on the mercury intrusion porosimetry(MIP)*** the model validation,different tests on COx claystone under different loading paths are *** between experimental and simulated results indicated that the present model is able to well describe the viscoplastic behaviour of damaged COx claystone,including swelling/shrinkage,triaxial extension and compression,and triaxial creep.

关键词： Callovo-Oxfordian(COx)claystone Excavation damage Time-dependent behaviour Suction Viscoplastic model

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

Acousto-optic scanning multi-photon lithography with high printing rate

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Opto-Electronic Advances 2024年第2期7卷 1-3页

作者： Minghui hong Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361005China

As a manufacturing method that is focused on end-users,3D printing has gained a lot of attention in recent years due to its unique advantages in fabricating complex three-dimensional *** new micro-nano 3D printing methods have been developed to meet the demand for high-precision and high-yield *** them,multi-photon-photon lithography(MPL) is a promising 3D nanofabrication technology due to its capability of true 3D digital processing and nanoscale processing resolution beyond the diffraction *** has been widely used to fabricate microoptics10,11,photonic crystals12,microfluidics13,meta-surfaces14,and mechanical metamaterials15.

关键词： photon Acous scanning

Study on the tunnel shape and soil-lining interaction influencing the lining behavior under seismic loading

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Earthquake Engineering and Engineering Vibration 2024年第4期23卷 845-862页

作者： Pham, Van Vi Do, Ngoc anh Osinski, Piotr Do, Ngoc Thai Dias, Daniel Sustainable Development in Underground Engineering Research Team Hanoi University of Mining and Geology Hanoi Vietnam Department of Underground and Mining Construction Faculty of Civil Engineering Hanoi University of Mining and Geology Hanoi Vietnam Department of Geotechnical Engineering Institute of Civil Engineering Warsaw University of Life Sciences - SGGW Warszawa Poland Laboratory 3SR Grenoble Alpes University Grenoble France

The response of tunnels subjected to seismic loading is a complex mechanism and depends not only on the seismic nature but also on tunnel structure and surrounding soil properties. The individual behavior of circular, rectangular, and sub-rectangular tunnels subjected to seismic loadings has already been studied in the literature. In the present research, two case scenarios of circular, rectangular tunnels and four sub-rectangular shaped tunnels, with similar cross-section areas, were adopted to perform a comprehensive numerical investigation. The purpose of the study was to determine the mechanical behavior of tunnels of different shapes, depending upon seismic conditions. Analyses were performed by considering the influence of soil-lining interaction, soil parameters, and lining thickness, as well as lining rigidity. Computations were performed for no-slip and full-slip conditions. The results indicate that the tunnel shape design is of great importance when regarding the mechanical behavior of the surrounding soil. This concerns no-slip as well as full-slip soil-lining interaction, especially when the lining is subjected to seismic loading. Moreover, it is shown that changes in incremental bending moments for circular, rectangular and sub-rectangular tunnels that depend upon the soil-lining interaction conditions differ significantly.

关键词： tunnel shape soil-lining interaction seismic loading internal forces numerical analysis