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International Soil and Water Conservation Research 2018年第2期6卷 99-110页

作者： tung gia pham Jan Degener Martin Kappas Cartography GIS and Remote Sensing DepartmentGottingen UniversityGermany University of Agriculture and Forestry Hue UniversityVietnam

Central Vietnam is very susceptible to soil erosion due to its complicated terrain and heavy rainfall. The objective of this study was to quantify soil erosion in the A Sap river basin, A Luoi district, Thua Thien Hue Province, Vietnam, using the Universal Soil Loss Equation (USLE) and Geographical Informa-tion System (GIS). The results showed that 34% of land area lost accumulated to 10 t ha-1 year-1 while 47% of the total area lost less than 1 t ha-1 year-1. Natural forest land lost the most with an average of about 19 t ha-1 year-1, followed by plantation forest with approximately 7 t ha-1 year-1 and other agricultural lands at 3.70 and 1.45 t ha-1 year-1 for yearly crops and paddy rice, respectively. Soil erosion was most sensitive to the topographic factor (LS), followed by the practice support factor (P), soil erodibility factor (K), cropping management (C), and the rainfall erosivity factor (R). Implications are that changes to the cultivated calendar and implementing intercropping are effective ways to prevent soil erosion in cultivated lands. Furthermore, introducing broad leaves trees for mountainous areas in A Sap basin was the most effective practice in reducing soil erosion. The study also pointed out that the combination of available data sources used with the USLE and GIS technology is a viable option to cal-culate soil erosion in Central Vietnam, which would allow targeted attention toward a solution is to reduce future soil erosion.

关键词： Central Vietnam GIS Soil erosion USLE

Assessment of soil quality indicators under different agricultural land uses and topographic aspects in Central Vietnam

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International Soil and Water Conservation Research 2018年第4期6卷 280-288页

作者： tung gia pham Hung Trong Nguyen Martin Kappas Cartography GIS and Remote Sensing DepartmentGottingen UniversityGeorge August University of GoettingenGoldschmidstr.537077 GoettingenGermany University of Agriculture and Forestry Hue UniversityVietnam Ministry of Natural Resources and Environment Vietnam

Soil quality assessment is valuable for agricultural production. In this research, 155 soil samples at two soil depths were collected from four land use types in an agricultural area of the A Luoi district in the Central Vietnam. Differences of soil organic carbon, total nitrogen in soil and soil pH under different land use types and topographic aspects were compared. Soil organic carbon contents in arable land and plantation forest are higher than those in natural forest and grassland (p < 0.05). Conversely, the total nitrogen in natural forest was significantly lesser in comparison to other land use types. Meanwhile there were no significant differences of the total nitrogen content (p < 0.05) among arable land, plantation forest, and grassland. The soil of grassland, natural and plantation forests land use types were more significantly acidic than those of the soils of the arable land use type. Soil organic carbon and total nitrogen showed a decreasing trend while soil depth increased in all land use types. The soil pH in plantation forest and arable land use types showed no significant change in relation to soil depth. Significant differences were not found in topographic aspects and soil organic carbon content;however, the different changing trends of soil organic carbon content between land use types and aspects were found. The impact of slope, elevation, farming system or soil texture accounted for the differences in these soil indicators under different land use types in the A Luoi district.

关键词： Central Vietnam Land use type Hilly area Soil quality Topographic aspects

Drought and conflicts at the local level: Establishing a water sharing mechanism for the summer-autumn rice production in Central Vietnam

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International Soil and Water Conservation Research 2019年第4期7卷 362-375页

作者： Chuong Van Huynh Catharien Terwisscha van Scheltinga Ty Huu pham Non Quoc Duong Phuong Thi Tran Linh Hoang Khanh Nguyen tung gia pham Ngoc Bich Nguyen Jos Timmerman Hue University Viet Nam Climate Change and Adaptive Land and Water Management Group Wageningen Environmental ResearchNetherlands University of Agriculture and Forestry Hue UniversityViet Nam

In recent years,water for agricultural production gradually became a significant challenge in the context of climate change in *** solutions are required,which consider the use of resources for both human needs and ecology,and that account for the equitable distribution and the livelihood of the farmers now and in the *** particular,the farmers in the province of Quang Nam faring water shortage in the cultivation of paddy in the summer-autumn *** arise regarding the sharing of the water between the farmers,the drinking water company and the hydropower *** the context of climate change,the water shortage is expected to increase in the *** article presents the results of participatory action research (PAR) approach to develop a local level mechanism for water sharing,in which stakeholders actively *** sharing mechanism was developed,envisioning a sustainable solution for inclusive water *** mechanism was successfully implemented in two cases,one at commune level (Tho stream) and one at the district level (Mo stream).The participatory approach proved to be successful in setting up a broadly acceptable mechanism that will need to be further incorporated in the institutional set-up.

关键词： Adaptation Agriculture Climate change Governance Rice production Water sharing

Development of a Peristaltic Micropump for Bio-Medical Applications Based on Mini LIPCA

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Journal of Bionic Engineering 2008年第2期5卷 135-141页

作者： Thanh tung Nguyen My pham Nam Seo Goo Department of Aerospace Engineering Konkuk University Department of Advanced Technology Fusion Konkuk University

This paper presents the design, fabrication, and experimental characterization of a peristaltic micropump. The micropump is composed of two layers fabricated from Polydimethylsiloxane （PDMS） material. The first layer has a rectangular channel and two valve seals. Three rectangular mini lightweight piezo-composite actuators are integrated in the second layer, and used as actuation parts. Two layers are bonded, and covered by two Polymethyl Methacrylate （PMMA） plates, which help increase the stiffness of the micropump. A maximum flow rate of 900μ*** 1 and a maximum backpressure of 1.8 kPa are recorded when water is used as pump liquid. We measured the power consumption of the micropump. The micropump is found to be a promising candidate for bio-medical application due to its bio-compatibility, portability, bidirectionality, and simple effective design.

关键词： peristaltic micropump LIPCA PDMS bio-medical applications

Development of an automatic and knowledge-infused framework for structural health monitoring based on prompt engineering

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Frontiers of Structural and Civil Engineering 2024年第11期18卷 1752-1774页

作者： Truong-Thang NGUYEN Viet-Hung DANG Thanh-tung pham Faculty of Building and Industrial Construction Hanoi University of Civil EngineeringHanoi 11600Vietnam Research Group of Development and application of advanced materials and modern technologies in construction Hanoi University of Civil EngineeringHanoi 11600Vietnam

Collecting and analyzing vibration signals from structures under time-varying excitations is a non-destructive structural health monitoring approach that can provide meaningful information about the structures’safety without interrupting their normal *** paper develops a novel framework using prompt engineering for seamlessly integrating users’domain knowledge about vibration signals with the advanced inference ability of well-trained large language models(LLMs)to accurately identify the actual states of *** proposed framework involves formulating collected data into a standardized form,utilizing various prompts to gain useful insights into the dynamic characteristics of vibration signals,and implementing an in-house program with the help of LLMs to perform damage *** advantages,as well as limitations,of the proposed method are qualitatively and quantitatively assessed through two realistic case studies from literature,demonstrating that the present method is a new way to quickly construct practical and reliable structural health monitoring applications without requiring advanced programming/mathematical skills or obscure specialized programs.

关键词： structural health monitoring vibration large language model signal processing prompt engineering

Performance evaluation of a two-way relay network with energy harvesting^and hardware noises

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Digital Communications and Networks 2021年第1期7卷 45-54页

作者： Nguyen Tien tung pham Minh Nam Phu Tran Tin Faculty of Electronics Technology Industrial University of Ho Chi Minh CityHo Chi Minh CityVietnam Wireless Communcations Research Group Faculy of Electrical and Electronics EngineeringTon Duc Thang UniversityHo Chi Minh CityVietnam

In this paper,we propose a Two-Way Cognitive Relay Network(TWCRN)where the secondary users operate on an underlay mode to access the licensed *** the proposed protocols,two secondary sources transmit their data to a relay in the first time slot,and then the relay would forward the received information to both sources in the remaining ***,the relay is self-powered by harvesting energy from ambient Radio Frequency(RF)signals,using the Time Switching(TS)and the Power Switching(PS)*** paper concentrates on eval-uating the performance of the secondary networks under the impact of hardware impairments and co-channel interference from the primary *** particular,based on the secondary transmitters'constraint power,we derive the closed-form expressions of the outage probability and the throughput over Rayleigh fading channels in two cases:TS and *** also investigate the energy efficiency issue and the locally optimal position of the relay to maximize the system throughput,which provides much information to install the relay ***,our derivations are verified by Monte Carlo simulation.

关键词： Energy harvesting Two-way relay Energy efficiency Hardware impairments Cognitive network

Electromechanical admittance-based automatic damage assessment in plate structures via one-dimensional CNN-based deep learning models

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Frontiers of Structural and Civil Engineering 2024年第11期18卷 1730-1751页

作者： Thanh-Canh HUYNH Nhat-Duc HOANG Quang-Quang pham gia Toai TRUONG Thanh-Truong NGUYEN Institute of Research and Development Duy Tan UniversityDa Nang 550000Vietnam Faculty of Civil Engineering Duy Tan UniversityDa Nang 550000Vietnam Bridge and Road Department Danang Architecture UniversityDa Nang 550000Vietnam Faculty of Civil Engineering and Technology Dong A UniversityDa Nang 550000Vietnam Industrial Maintenance Training Center Ho Chi Minh City University of Technology(HCMUT)Ho Chi Minh City 700000Vietnam

The conventional admittance approach utilizing statistical evaluation metrics offers limited information about the damage location,especially when damage introduces nonlinearities in admittance *** study proposes a novel automated damage localization method for plate-like structures based on deep learning of raw admittance signals.A one-dimensional(1D)convolutional neural network(CNN)-based model is designed to automate processing of raw admittance response and prediction of damage probabilities across multiple locations in a monitored *** admittance data set is augmented with white noise to simulate realistic measurement *** K-fold cross-validation technique is employed for training and testing the *** experimental validation of the proposed method shows that the proposed method can accurately identify the state and damage location in the plate with an average accuracy of 98%.Comparing with established 1D CNN models reveals superior performance of the proposed method,with significantly lower testing *** proposed method exhibits the ability to directly handle raw electromechanical admittance responses and extract optimal features,overcoming limitations associated with traditional piezoelectric admittance *** eliminating the need for signal preprocessing,this method holds promise for real-time damage monitoring of plate structures.

关键词： convolutional neural network electromechanical admittance electromechanical impedance piezoelectric transducer damage localization plate structure deep learning structural health monitoring

Tunable colors and conductivity by electroless growth of Cu/Cu2O particles on sol-gel modified cellulose

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Nano Research 2020年第10期13卷 2658-2664页

作者： Justus Landsiedel Waleri Root Christian Schramm Alexander Menzel Steffen Witzleben Thomas Bechtold tung pham Research Institute for Textile Chemistry and Textile Physics University of Innsbruck6850 DornbirnAustria Department of Physical Chemistry University of Innsbruck6020 InmsbruckAustria Department of Natural Sciences Bonn Rhein sSieg University of Applied Sciences5359 RheinbachGermany

Development of colored surfaces by formation of nano-structured aggregates is a widely used strategy in nature to color lightweight structures (e.g. butterflies) without the use of dye pigments. The deposition of nanoscale particles mimics nature in it’s approach coloring surfaces. This work presents sol-gel modification of cellulose surfaces used to form a template for growth of Cu/Cu2O core–shell particles with defined size-distributions. Besides improving the adhesion of the deposited particulate material, the sol-gel matrix serves as a template for the control of particle sizes of the Cu/Cu2O structures, and as a consequence of particle size variation the surface color is tunable. As an example, red color was achieved with an average particle size of 35 nm, and shifts gradually to blue appearance when particles have grown to 80 nm on the sol-gel modified fabric. The copper concentration on representative fabrics is kept low to avoid modifying the textile characteristics and were all in the range of 150–170 mg per g of cellulose material. As a result of copper deposition on the surface of the material, the cellulose fabric also became electrically conductive. Remarkably, the electrical conductivity was found to be dependent on the average particle sizes of the deposits and thus related to the change in observed color. The generation of color by growth of nano-sized particles on sol-gel templates provides a highly promising approach to stain surfaces by physical effects without use of synthetic colorants, which opens a new strategy to improve environmental profile of coloration.

关键词： electroless copper deposition sol-gel support thin film structural coloration tunable sheet resistance LSPR

Enhancing sensitivity in atomic force microscopy for planar tip-on-chip probes

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Microsystems & Nanoengineering 2022年第3期8卷 39-49页

作者： H.tung Ciftci Michael Verhage Tamar Cromwijk Laurent pham Van Bert Koopmans Kees Flipse Oleg Kurmosikov Department of Applied Physics Eindhoven University of TechnologyPO Box 5135600 MB Eindhoventhe Netherlands DRF/RAMIS/SPEC-LEPO Centre CEA de Saclay91191 Gif-sr-VvetteFrance Institut Jean Lamour Lorraine University54000 NancyFrance

We present a new approach to tuning-fork-based atomic force microscopy for utilizing advanced"tip-on-chip"probes with high sensitivity and broad ***,such chip-like probes with a size reaching 2×2 mm^(2)drastically perturb the oscillation of the tuning fork,resulting in poor performance in its intrinsic force ***,restoring initial oscillatory characteristics is necessary for regaining high *** this end,we developed a new approach consisting of three basic steps:tuning-fork rebalancing,revamping holder-sensor fixation,and electrode *** rebalancing allows the tuning fork to recover the frequency and regain high Q-factor values up to 10^(4)in air and up to 4×10^(4)in ultra-high vacuum *** floating-like holder-fxation using soft wires significantly reduces energy dissipation from the mounting *** with the soft wires,reconfigured electrodes provide electrical access to the chip-like probe without intervening in the force-sensing ***,our easy-to-implement approach allows converting the atomic force microscopy tip from a passive tool to a dedicated microdevice with extended functionality.

关键词： tuning atomic utilizing

Effect of CO_(2)-mixing dose and prolonged mixing time on fresh and hardened properties of cement pastes

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2023年第10期24卷 886-897页

作者： Minlu WANG Shuang LUO Ba tung pham tung-Chai LING College of Civil Engineering Hunan UniversityChangsha 410082China

This study aims to investigate the influence of CO_(2)-mixing dose(mass fractions of 0.3%,0.6%,and 0.9%)and prolonged mixing time on the fresh and hardened properties of cement *** CO_(2)-mixing can act as coagulant in fresh cement mixtures,resulting in a significant reduction in workability associated with the formation of a rich calcium carbonate network on the surface of cement *** CO_(2)-mixing cement pastes were found to be much stiffer and more difficult to handle,place,and compact than the control mixture,which had a negative effect on the mechanical strength performance of the hardened ***,prolonging the mixing time for 1 min(immediately after CO_(2)-mixing)can effectively improve the workability(by~53%–85%)by breaking up the flocculation network of deposited calcium *** a result,the presence of detached calcium carbonate accelerated early cement hydration and densified the microstructure;this improved early-age compressive strength by~6%–32%,depending on the CO_(2)-mixing dose ***,it seems that the CO_(2)-mixing dose should be controlled at≤0.6%with the mixing time prolonged in order to attain satisfactory workability and mechanical strength.

关键词： CO_(2)-mixing Calcium carbonate Early cement hydration Flowability Microstructure