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High-performance carbon fiber/gold/copper composite wires for lightweight electrical cables

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Journal of Materials Science & Technology 2020年第7期42卷 46-53页

作者： Thang Q.Tran Jeremy Kong Yoong Lee Amutha Chinnappan nguyen huu Loc Long T.Tran Dongxiao Ji W.A.D.M.Jayathilaka Vishnu Vijay Kumar Seeram Ramakrishna Department of Mechanical Engineering National University of Singapore9 Engineering Drive 1EA-07-05Singapore 117575Singapore Faculty of Mechanical Engineering Ho Chi Minh City University of TechnologyVNUHCM268 Ly Thuong KietDistrict 10Ho Chi Minh City 740400Viet Nam

In this study,we synthesized high-performance Carbon Fiber/Gold/Copper(CF/Au/Cu)composite wires by using a 2-step deposition method via sputtering and *** Au was sputtered on PANbased CFs as a pre-treatment,the wettability and surface reactivity of the CFs were improved,resulting in a homogeneous deposition of Cu on their *** different Cu electrodeposition time,the resulting CF/Au/Cu composite wires could possess a high strength of up to 3.27 GPa(~10 times stronger than copper wires)while their electrical conductivity could be as high as 4.4×10^5 S/cm(~75%of that for copper).More importantly,since the composite wires were lightweight(up to 70%lower than Cu mass density),they are a promising candidate to substitute conventional heavy metal wires in the future electrical applications.

关键词： Carbon fiber Copper composite wires Strength Electrical properties

Recognition of earthquake-prone nodes,a case study for North Vietnam (M≥5.0)

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Geodesy and Geodynamics 2012年第2期3卷 14-26页

作者： nguyen huu Tuyen Ngo Thi Lu Institute of Geophysics Vietnam Academy of Science and Technology A8/18.Hoang Quoc VietHanoiVietnam Earth's System Physics(ESP) International Centre for Theory Physics(ICTP)Strada Costiera 1134151 TriesteItaly

Morphostructural nodes in North Vietnam are delineated with the morphostructural zoning （MZ） method, and classified into seismogenic and non-seismogenic nodes. The compiled morphostructural map （ scale 1 ： 1000000） shows a three-level hierarchical structure of blocks, boundary zones, and nodes. The identified nodes are classified with the pattern-recognition algorithm CORA-3 into those that are prone to generate M≥5.0 earthquakes and those that are not. Some of the earthquake-prone nodes coincide with epicenters of M ≥ 5.0 earthquakes that have occurred ; others may coincide with such events in the future.

关键词： North Vietnam morphostructural zoning pattern recognition seismogenic nodes

Comparative study on water-soluble inorganic ions in PM2.5 from two distinct climate regions and air quality

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Journal of Environmental Sciences 2020年第2期32卷 349-360页

作者： Duong huu Huy Le Tu Thanh To Thi Hien Norimichi Takenaka Faculty of Food Science and Technology Ho Chi Minh City University of Food Industry140 Le Trong Tan StreetTan Phu DistrictHo Chi Minh CityViet Nam Faculty of Environment University of ScienceVietnam National University–Ho Chi Minh City227 Nguyen Van Cu StreetDistrict 5Ho Chi Minh CityViet Nam Graduate School of Humanities and Sustainable System Sciences Osaka Prefecture University1-1 Gakuen-choNaka-kuSakai-shiOsaka 599-8531Japan

Recently, air quality has significantly improved in developed country, but that issue is of concern in emerging megacity in developing *** this study, aerosols and their precursor gas were collected by NILU filter pack at two distinct urban sites during the winter and summer in Osaka, Japan and dry and rainy seasons in Ho Chi Minh City(HCMC),*** aims are to investigate the contribution of water-soluble inorganic ions(WSIIs) to PM2.5, thermodynamic characterization and possible formation pathway of secondary inorganic aerosol(SIA).The PM2.5 concentration in Osaka(15.8 μg/m^3) is lower than that in HCMC(23.0 μg/m^3), but the concentration of WSIIs in Osaka(9.0 μg/m^3) is two times higher than that in HCMC(4.1 μg/m^3).Moreover, SIA including NH4^+, NO3^-and SO4^2-are major components in WSIIs accounting for 90% and 76%(in molar) in Osaka and HCMC,*** models were used to understand the thermodynamic characterization of urban ***, statistical analysis results indicate that very good agreement(R2> 0.8) was found for all species, except for nitrate aerosol in *** found that when the crustal species present at high amount, those compositions should be included in model calculation(*** the HCMC situation).Finally, we analyzed the characteristics of NH4^+– NO3^-– SO4^2-system.A possible pathway to produce fine nitrate aerosol in Osaka is via the homogeneous reaction between NH3 and HNO3, while nonvolatile nitrate aerosols can be formed by the heterogeneous reactions in HCMC.

关键词： Water-soluble inorganic ions Thermodynamic model PM2.5

SOME PRELIMINARY RESULTS FROM STUDY OF CRUSTAL DEFORMATION IN VIETNAM

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大地测量与地球动力学 2003年第B12期23卷 114-118页

作者： Cao Dinh Trieu Le Van Dung nguyen huu Tuyen Pham Nam Hung Institute of Geophysics Institute of GeophysicsInstitute of GeophysicsInstitute of Geophysics 18 Hoang Quoc Viet Road Cau GiayHanoi18 Hoang Quoc Viet Road Cau GiayHanoi18 Hoang Quoc Viet Road Cau GiayHanoi18 Hoang Quoc Viet Road Cau GiayHanoi

In this work, the authors present some results of strain monitoring within the territory of Vietnam from 1984 to 2001. Data analysis shows that (1) the Phu Lien area is tectonically stable with low strain rate, 1×10\+\{-6\} /a; (2) the Hoa Binh area has indication of tectonic instability with relatively high strain rate of the earth crust: absolute value of the strain reaching 100×10\+\{-6\}, usual average strain amplitude of 60×10\+\{-6\}, whereas the monthly average strain intensity varies in a range from 30×10\+\{-6\} to 50×10\+\{-6\}; (3) there are clear indications of the strain state of the earth crust before occurrence of earthquakes of medium or higher magnitude. This is a very important indication in the research and short term prediction of earthquakes, especially for the areas with low seismic stability like the NW of Vietnam.

关键词：越南表层变形应变测量系统操作原则应变数据因变与地震相对关系地震活动特性

VSC-HVDC等效谐波阻抗与谐波谐振特性研究

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华北电力大学学报（自然科学版） 2015年第2期42卷 8-14页

作者： nguyen phuc Huy 韩民晓华北电力大学电气与电子工程学院北京102206

现代电压源型换流器(VSC)能够产生准正弦波形,但对基于PWM的电平数较少的VSC,谐波含量仍然较大,需要配置性能良好的滤波器。从交直流两侧看入,换流器有一个等效谐波阻抗。估算此谐波阻抗对滤波器的设计和谐波谐振分析有着重要作用。基... 详细信息

现代电压源型换流器(VSC)能够产生准正弦波形,但对基于PWM的电平数较少的VSC,谐波含量仍然较大,需要配置性能良好的滤波器。从交直流两侧看入,换流器有一个等效谐波阻抗。估算此谐波阻抗对滤波器的设计和谐波谐振分析有着重要作用。基于开关函数的定量分析,利用VSC两侧的谐波的相互作用来计算等效谐波阻抗。同时分析了开关函数各开关分量之间的交叉调制给谐波阻抗计算带来的影响。此外,还进行了基于电压源换流器的高压直流输电的交直流两侧的谐振分析。从VSC直流侧看入的谐波阻抗虽然很大,但由于直流分压电容和直流电缆的寄生电容的影响,仍存在谐振的可能性。在交流侧,谐振可能出现在换流器的输出端口,且可能存在谐波放大现象。

关键词：电压源换流器电压源换流器的高压直流输电谐波谐振谐波阻抗

直流阻容式电压互感器用于直流输电谐波电压测量的研究

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电工电能新技术 2015年第3期34卷 54-60页

作者： nguyen phuc Huy 韩民晓华北电力大学电气与电子工程学院北京102206

谐波问题的分析与控制是保证高压直流输电系统正常运行的重要内容。为了寻找最适当的测量方法,需要对电压谐波测量进行深入研究。直流电压互感器(DCVT)是测量直流输电系统电压的重要设备。本文介绍与分析了阻容式直流电压互感器的主要... 详细信息

谐波问题的分析与控制是保证高压直流输电系统正常运行的重要内容。为了寻找最适当的测量方法,需要对电压谐波测量进行深入研究。直流电压互感器(DCVT)是测量直流输电系统电压的重要设备。本文介绍与分析了阻容式直流电压互感器的主要组件的特性,如同轴电缆、A/D与D/A转换器、光耦合器,详细分析了分压器的对地杂散电容对电压互感器频率响应的影响,非理想状态下元器件对测量误差的影响。理论分析指出选择一个合适的并联电阻的电容可以减小分压器对地杂散电容的影响,并且可选择精密电阻和电容来减少测量误差。实验结果表明,阻容式直流电压互感器适合直流谐波电压测量,而且测量误差小于0.2%,可达到10k Hz的频率带宽。

关键词：高压直流输电谐波谐波电压测量直流电压测量直流阻容式电压互感器阻容分压器频率响应

Improved flood susceptibility mapping using a best first decision tree integrated with ensemble learning techniques

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Geoscience Frontiers 2021年第3期12卷 333-342页

作者： Binh Thai Pham Abolfazl Jaafari Tran Van Phong Hoang Phan Hai Yen Tran Thi Tuyen Vu Van Luong huu Duy nguyen Hiep Van Le Loke Kok Foong University of Transport Technology Ha Noi 100000Viet Nam Research Institute of Forests and Rangelands Agricultural ResearchEducation and Extension Organization(AREEO)TehranIran Institute of Geological Sciences Vietnam Academy of Sciences and Technology84 Chua Lang StreetDong daHa NoiViet Nam Department of Geography School of Social EducationVinh UniversityViet Nam Department of Resource and Environment Management School of Agriculture and ResourcesVinh UniversityViet Nam Faculty of Geography VNU University of Science334 Nguyen TraiHa NoiViet Nam Institute of Research and Development Duy Tan UniversityDa Nang 550000Viet Nam Department for Management of Science and Technology Development Ton Duc Thang UniversityHo Chi Minh CityViet Nam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh CityViet Nam

Improving the accuracy of flood prediction and mapping is crucial for reducing damage resulting from flood *** this study,we proposed and validated three ensemble models based on the Best First Decision Tree(BFT)and the Bagging(Bagging-BFT),Decorate(Bagging-BFT),and Random Subspace(RSS-BFT)ensemble learning techniques for an improved prediction of flood susceptibility in a spatially-explicit manner.A total number of 126 historical flood events from the Nghe An Province(Vietnam)were connected to a set of 10 flood influencing factors(slope,elevation,aspect,curvature,river density,distance from rivers,flow direction,geology,soil,and land use)for generating the training and validation *** models were validated via several performance metrics that demonstrated the capability of all three ensemble models in elucidating the underlying pattern of flood occurrences within the research area and predicting the probability of future flood *** on the Area Under the receiver operating characteristic Curve(AUC),the ensemble Decorate-BFT model that achieved an AUC value of 0.989 was identified as the superior model over the RSS-BFT(AUC=0.982)and Bagging-BFT(AUC=0.967)models.A comparison between the performance of the models and the models previously reported in the literature confirmed that our ensemble models provided a reliable estimate of flood susceptibilities and their resulting susceptibility maps are trustful for flood early warning systems as well as development of mitigation plans.

关键词： Machine learning Ensemble learners Hybrid modeling

Influence of dietary mannan oligosaccharides supplementation on fingerling clownfish, Amphiprion ocellaris (Cuvier, 1830)

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Journal of Coastal Life Medicine 2017年第8期5卷 325-329页

作者： Hoang Do-huu Trung Kien nguyen Vietnam Academy of Science&Technology(VAST)-Institute of Oceanography 01 Cau DaNha TrangVietnam

Objective: To test the effects of dietary mannan oligosaccharides (MOS) on clownfish Amphiprion ocellaris (A. ocellaris). Methods: Six levels (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 g/kg diet) of MOS were added to the basal diet (used as control diet) and fed clownfish A. ocellaris [total length (24.21 ± 0.16) mm] for 70 days. Growth performance and tissue protein were measured. Results: The result showed that growth rate was enhanced significantly in fish fed 0.10% and 0.15% MOS in diets compared to fish fed other MOS levels or control (P < 0.05). Survival rate significantly increased in fish fed diets with 0.20% and 0.25% MOS, compared to control. Fraction rates of protein growth were significantly higher in fish fed diets with 0.15%, 0.20%and 0.25% MOS supplementation than those fish fed other MOS inclusion levels and the control (P < 0.04). Dietary MOS concentrations and clownfish growth rates were significantly correlated. Optimal MOS concentration was predicted to be 0.185%, 0.173% and 0.171% at Days 14, 42 and 70, respectively. Conclusions: In conclusion, MOS-supplemented diet benefits for boosting growth, survival and body composition of the clownfish, A. ocellaris.

关键词： Amphiprion ocellaris Clownfish Mannan oligosaccharides Growth Body composition

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加密图像中的数据隐藏

加密图像中的数据隐藏

作者： nguyen THANH phuc（阮成福）华南理工大学

学位级别：硕士

近年来,随着互联网、移动设备、云计算和社交网络等技术的巨大进步,大量的数据在网络上存储和传输。数据的拥有者们只需要很少的代价,就可以将他们的数据委托存储在云端,并享受着方便的数据管理服务。而在这大量的委托存储数据中,具有... 详细信息

近年来,随着互联网、移动设备、云计算和社交网络等技术的巨大进步,大量的数据在网络上存储和传输。数据的拥有者们只需要很少的代价,就可以将他们的数据委托存储在云端,并享受着方便的数据管理服务。而在这大量的委托存储数据中,具有隐私信息的图片占据了很大一部分。正因如此,这类具有个人隐私信息或者商业信息的图片的安全性要求迫在眉睫。在这类问题中,加密技术是一种最常见的解决方法,但是加密后的图片非常不便于分享和管理。为了满足管理上的需求,诸如拥有者、存储位置和时间戳等,辅助信息常常伴随着加密后的图片一起存储,而这些辅助信息往往对原始内容并没有什么影响。基于以上的观察,本论文将研究在加密图像中嵌入秘密信息的方法。在加密图像中嵌入秘密信息需要满足以下的要求:安全性、可逆性、可分离性和容量等。大多数已存在的方法并不能很好的满足以上提到的几个特性。为了解决这个问题,本文提出了一种新颖的加密域图像隐写方法。基于加密前预留空间框架,一幅原始图像先被分成两个部分,然后各自进行XOR和AES加密,从而提供安全性保证。在加密和预留空间的处理过程中使用差分扩展和奇偶转换来满足加密域可逆隐写的几个要求。同时,在加密图像中将会使用一种新颖的嵌入方法来嵌入辅助信息,该方法基于通过使用秘密像素点最低位隐藏信息的LSB技术。我们可以从嵌有秘密信息的加密图像中准确提取出秘密信息或者无失真地还原图像,信息提取和图像加密两个过程是可分离的。换句话说,只要拥有解密密钥和提取密钥,接收者可以先提取后解密或者先解密后提取。新方法的一个特别的特性就是只要拥有解密密钥,就可以直接将加密隐写后的图像还原,不需要提取出秘密信息(跟以前的其他算法不一样的)。我们还通过实验证明了本文提出的加密域可逆隐写方法拥有很大的嵌入容量。在Windows系统上,我们用C#语言实现了提出的方法,并在两个常见的图像数据库上进行了大量的实验。实验结果表明了所提出方法的有效性。同时,嵌入容量可以达到0.3 bpp或者更高,高于其他相关工作。另外,对应的PSNR值在可接受范围内(对于Lena图像,当嵌入率为0.2 bpp时,第一种方法的PSNR值为33.09 dB,第二种方法的PSNR值为58.12 dB)。最后,通过理论分析验证了所提出的方法的安全性、可逆性和可分离性。

关键词：数据隐藏加密图像可逆可分离高容量