检索结果-南通市图书馆

Earthquake Engineering and Engineering Vibration 2020年第1期19卷 179-188页

作者： thanh nguyen Chi Gospodarikov Alexandr Saint Petersburg Mining University Saint PetersburgRussia Federation Hanoi University of Mining and Geology HanoiVietnam

tunnels are now an integral part of the infrastructure in major cities around the world. For many reasons, these tunnels have horseshoe-shaped cross-sections with round top and flat bottom. this paper presents some improvements to the use of the Hyperstatic Reaction Method-HRM for analysing tunnels with horseshoe-shaped cross-sections when these tunnels operate under the influence of earthquakes, particularly in cases when the tunnel lining is a continuous lining. the analysis used parameters of a tunnel from the Hanoi metro system, as well as parameters of the strongest earthquake that may occur in the central Hanoi area in the improved HRM and 2 D numerical methods using the ABAQUS software. On the basis of the results obtained, the paper gives conclusions about the HRM methodology when it is used to calculate tunnels that have horseshoe cross-sections operating under the influence of earthquakes.

关键词： hyperstatic reaction method earthquake horseshoe cross-section impact tunnel

Multilevel threshold Based Image Denoising in Curvelet Domain

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & technology 2010年第3期25卷 632-640页

作者： nguyen thanh Binh Ashish Khare Department of Electronics and Communication University of Allahabad

In this paper, we propose a multilevel thresholding technique for noise removal in curvelet transform domain which uses cycle-spinning. Most of uncorrelated noise gets removed by thresholding curvelet coefficients at lowest level, while correlated noise gets removed by only a fraction at lower levels, so we used multilevel thresholding on curvelet coefficients. the threshold in the proposed method depends on the variance of curvelet coefficients, the mean and the median of absolute curvelet coefficients at a particular level which makes it adaptive in nature. Results obtained for 2-D images demonstrate an improved performance over other recent related methods available in literature.

关键词： curvelet transform denoising multilevel thresholding cycle-spinning

Bubble entrapment during the recoil of an impacting droplet

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2020年第1期6卷 768-774页

作者： thanh-Vinh nguyen Masaaki Ichiki Sensing System Research Center National Institute of Advanced Industrial Science and Technology(AIST)Japan1-2-1 NamikiTsukuba-shiIbaraki 305-8564Japan

When a droplet impacts a(super-)hydrophobic surface,there is a range of Weber numbers within which bubble entrapment will occur during droplet recoil due to closure of the air cavity developed when the droplet spreads out during the *** this study,we studied bubble entrapment using a microelectromechanical system(MEMS)-based acoustic sensor fabricated on a *** found that bubble entrapment is followed by an acoustic vibration that can be detected by the ***,the frequency of the vibration is inversely proportional to the radius of the droplet,which indicates that this vibration is the resonant oscillation of the ***,the MEMS-based acoustic sensor can be used not only to detect but also to measure the size of the entrapped ***,we demonstrated that it is possible to prevent bubble formation by allowing the air to escape to the underside of the droplet contact *** can be done by creating through-holes on the substrate or decorating the substrate with sufficiently large textures.

关键词： bubble radius resonant

A Simple Approach to the Fabrication of Graphene-Carbon Nanotube Hybrid Films on Copper Substrate by Chemical Vapor Deposition

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 2015年第5期31卷 479-483页

作者： nguyen Van Chuc Cao thi thanh nguyen Van tu Vuong t.Q Phuong Pham Viet thang Ngo thi thanh tam Institute of Materials Science Vietnam Academy of Science and Technology Hanoi University of Science Vietnam National University

In this study,graphene-carbon nanotube（CNt） hybrid films were directly synthesized on polycrystalline copper（Cu） substrates by thermal chemical vapor deposition（CVD） *** films were synthesized on Cu substrate at 1000 ℃ in mixture of gases:argon（Ar）,hydrogen（H2）,and methane（CH4）.then,carbon nanotubes（CNts） were grown uniformly on the surface of graphene/Cu films at 750 ℃ in mixture of Ar,*** acetylene（C2H2） *** salt FeCl3solution deposited onto the surface of graphene/Cu substrate by spin coating method was used as precursor for the growth of the *** density and quality of the CNts on the surface of graphene/Cu films can be controlled by varying the concentration of FeCl3salt catalyst.

关键词： Graphene Carbon nanotube(CNt) Hybrid films Copper

transfer Learning for Disease Diagnosis from Myocardial Perfusion SPECt Imaging

在线全文

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2022年第12期73卷 5925-5941页

作者： Phung Nhu Hai nguyen Chi thanh nguyen thanh trung tran trung Kien Institute of Information technology AMSTHanoi11307Vietnam Department of Medical Equipment 108 Military Central HospitalHanoi11610Vietnam

Coronary artery disease(CAD)is one of the most common pathological conditions and the major global cause of *** perfusion imaging(MPI)using single-photon emission computed tomography(SPECt)is a non-invasive method and plays an essential role in diagnosing ***,there is currently a shortage of doctors who can diagnose using SPECt-MPI in developing countries,especially *** on deploying machine learning and deep learning in supporting CAD diagnosis has been noticed for a long ***,these methods require a large dataset and are therefore time-consuming and *** study aims to develop a cost-effective and high-performance CAD classification model to support doctors in these *** this paper,we propose a transfer learning framework for a multi-stage training process with different learning *** process consists of two training stages:a warming up stage in which all layers of a pre-trained model(on ImageNet dataset)are frozen;and a finetuning stage in which a small amount of the top layers are unfrozen and then retrained with a lower learning *** dataset for this study consists of the polar maps from 218 *** popular CNN-based pre-trained models have been investigated,and ResNet152V2-based model has obtained the highest performances with an accuracy of 95.5%,area under the receiver operating characteristic curve(AUC)score 0.932,sensitivity 94.4%,precision 96.4%,and F1-score 95.2%.these performances are competitive or even better than all state-of-the-art approaches in terms of classification accuracy and *** also apply the class activation mapping technique to help explain the model’s predictions and increase the model’s reliability,proving capable of assisting the SPECt image readers in the CAD diagnosis.

关键词： Coronary artery disease deep learning transfer learning SPECtMPI polar maps

Assessment of Livelihood Vulnerability to Drought: A Case Study in Dak Nong Province, Vietnam

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Disaster Risk Science 2019年第4期10卷 604-615页

作者： nguyen thi thanh thao Dao nguyen Khoi tran thanh Xuan Bernard tychon Universite de Liege 6700 ArlonBelgium Institute for Environmental Science Engineeringand ManagementIndustrial University of Ho Chi Minh CityHo Chi Minh CityVietnam Institute of Research and Development Duy Tan UniversityDa NangVietnam Faculty of Environment University of ScienceVietnam National University Ho Chi Minh CityHo Chi Minh CityVietnam Ntt Institute of Hi-technology Nguyen Tat Thanh UniversityHo Chi Minh CityVietnam

In recent years,droughts have strongly affected the Central Highlands of Vietnam and have resulted in crop damage,yield decline,and serious water *** study investigated the livelihood vulnerability of five communities of farmers who are exposed to droughts in one of the more vulnerable regions of Vietnam—Dak Nong Province.A survey of 250 households was conducted in the five communities to collect data on the region’s sociodemographic profile,livelihood systems,social networks,health status,food and water security,drought conditions,and climate *** were aggregated using a livelihood vulnerability index and the IPCC vulnerability *** survey results indicate that Quang Phu community is the most vulnerable of the study’s communities,followed by Nam N’dir,Dak Nang,Duc Xuyen,and Dak D’ro in descending order of *** availability and livelihood strategies are the most important variables in determining the vulnerability of the five surveyed *** order to reduce vulnerability to droughts,water management practices and livelihood diversification in farming and nonfarming activities are recommended for the study area.

关键词： Agricultural drought Livelihood vulnerability Vietnam Vulnerability indicators

Streaming and congestion control using scalable video coding based on H.264/AVC

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第5期7卷 749-754页

作者： nguyen Dieu thanh OStERMANN Joern Institute of Information technology University of Hannover Hannover 30167 Germany

this paper presents a streaming system using scalable video coding based on H.264/AVC. the system provides a congestion control algorithm supported by channel bandwidth estimation of the client. It uses retransmission only for packets of the base layer to disburden the congested network. the bandwidth estimation allows for adjusting the transmission rate quickly to the current available bandwidth of the network. Compared to binomial congestion control, the proposed system allows for shorter start-up times and data rate adaptation. the paper describes the components of this streaming system and the results of experiments showing that the proposed approach works effectively for streaming video.

关键词： Scalable video coding, Congestion control, Bandwidth estimation, transport protocols, Retransmission

Novel Deletion in Exon 7 of Betaine Aldehyde Dehydrogenase 2(BADH2)

在线全文

学校读者我要写书评

暂无评论

Rice science 2023年第2期30卷 104-112,I0020-I0030页

作者： VAN Quoc Giang HUYNH Ky nguyen Chau thanh tung nguyen Loc Hien nguyen van Manh nguyen Nhut thanh VO Cong thanh SWEE Keong Yeap College of Agriculture Can Tho UniversityCan Tho 92000Vietnam Department of Sciences and technology of Long An Province Long An 850000Vietnam China-Association of Southeast Asian Nations College of Marine Sciences Xiamen University MalaysiaSepang 49000SelangorMalaysia

the fragrance of rice is one of the premium characteristics that breeders want to include in rice varieties due to the higher market value. Nucleotide deletions in exons 2(7 bp) and 7(8 bp) of Betaine Aldehyde Dehydrogenase 2(BADH2) are associated with fragrance in rice. In this study, a new 13 bp deletion in exon 7 of the BADH2 gene was discovered in the Nang thom Cho Dao(NtCD) variety, and the mutation has been closely related to the genetic background of indica subspecies through the Bayesian phylogenetic approach and haplotype network analysis of the 3 000 Rice Genomes Project. In addition, a set of functional markers(EX07-13F, EX07-13RN, and EX07-13RM) identified the 13 bp deletion only within NtCD(no amplified band) compared with both non-aromatic and other aromatic rice varieties(110 bp band). the deletion of 13 bases instead of 8 bases in exon 7 of BADH2 caused a premature stop codon, which down-regulated the expression of the BADH2 transcript while associated with up-regulation of OsP5CS and the high amount of 2-acetyl-1-pyrroline. It is potential to use the deletion in exon 7 of the BADH2 gene as a novel marker for adulteration and breeding of fragrant rice varieties, particularly for NtCD.

关键词： novel deletion BADH2 fragrant rice functional marker

Green Synthesis of Silver Nanoparticles Using Plectranthus Amboinicus Leaf Extract for Preparation of CMC/PVA Nanocomposite Film

在线全文

学校读者我要写书评

暂无评论

Journal of Renewable Materials 2021年第8期9卷 1393-1411页

作者： nguyen thi thanh thuy Le Hoang Huy truong thuy Vy nguyen thi thanh tam Bien thiLan thanh nguyen thi My Lan Nong Lam University Ho Chi Minh City Ho Chi Minh City700000Vietnam Industrial University of Ho Chi Minh City Ho Chi Minh City700000Vietnam University of Science Viet Nam National University Ho Chi Minh CityHo Chi Minh City700000Vietnam

In the present study,the biogenic silver nanoparticles have been synthesized using aqueous leaf extract of Plectranthus amboinicus(PA),which acted as both reducing and stabilizing *** PA synthesized silver nanoparticles were blended with carboxymethyl cellulose/polyvinyl alcohol(CMC/PVA)*** prepared AgNPs as well as the biogenic AgNPs incorporated CMC/PVA films were investigated using UV-visible spectrophotometry,Fourier-transform infrared spectroscopy(Ft-IR),dynamic light scattering(DLS),scanning electron microscope(SEM),and X–ray diffraction(XRD).the DLS results showed that biogenic AgNPs had the average particle size of 65.70 nm with polydispersity index of *** surface plasmon resonance of AgNPs,which was determined by UV-vis spectrophotometry,showed the value of 410.00 *** results therefore confirmed the reduction Ag+into Ag°and the formation of AgNPs in the *** SEM imaging showed that AgNPs was quasi-spherical and *** XRD peaks at 33.07°,44.19°,64.58°and 77.47°confirmed the crystalline nature and presence of *** CMC/PVA films that incorporated with AgNPs displayed best mechanical strength and morphological properties than the pure CMC/PVA *** film of CMC/PVA-AgNPs exhibited significant antibacterial activities against Bacillus spizizenii,Staphylococcus aureus,Salmonella typhi and Escherichia Coli.

关键词： Carboxymethyl cellulose antibacterial green synthesis silver nanoparticles plectranthus amboinicus polyvinyl alcohol

Numerical investigation of the influence of casting techniques on fiber orientation distribution in ECC

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2022年第11期16卷 1424-1435页

作者： Chung nguyen VAN Hai tRAN thanh thuc Nhu nguyen Jianchun LI Faculty of Civil Engineering Ho Chi Minh City University of Technology and EducationHo Chi Minh 721400Vietnam School of Civil and Environmental Engineering University of Technology SydneySydneyNSW 2007Australia School of Civil Engineering Hue Industrial CollegeHue 49120Vietnam

Engineered cementitious composites(ECC),also known as bendable concrete,were developed based on engineering the interactions between fibers and cementitious *** orientation of fibers,in this regard,is one of the major factors influencing the ductile behavior of this *** this study,fiber orientation distributions in ECC beams influenced by different casting techniques are evaluated via numerical modeling of the casting *** casting directions and two casting positions of the funnel outlet with beam specimens are modeled using a particle-based smoothed particle hydrodynamics(SPH)*** this SPH approach,fresh mortar and fiber are discretized by separated mortar and fiber particles,which smoothly interact in the computational domain of *** movement of fiber particles is monitored during the casting ***,the fiber orientations at different sections of specimens are determined after the fresh ECC stops flowing in the *** simulation results show a significant impact of the casting direction on fiber orientation distributions along the longitudinal wall of beams,which eventually influence the flexural strength of *** addition,casting positions show negligible influences on the orientation distribution of fibers in the short ECC beam,except under the pouring position.

关键词： ECC fiber orientation distribution casting direction casting position