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A voltage-controlled chaotic oscillator based on carbon nanotube field-effect transistor for low-power embedded systems

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Chinese Physics B 2014年第5期23卷 617-622页

作者： Van ha nguyen Wonkyeong Park Namtae Kim hanjung Song Department of Nano Systems Engineering Inje University Department of Electronics Engineering Inje University Center for Nano Manufacturing Inje University

this paper presents a compact and low-power-based discrete-time chaotic oscillator based on a carbon nanotube field-effect transistor implemented using Wong and Deng＇s well-known model. The chaotic circuit is composed of a nonlinear circuit that creates an adjustable chaos map, two sample and hold cells for capture and delay functions, and a voltage shifter that works as a buffer and adjusts the output voltage for feedback. The operation of the chaotic circuit is verified with the SPICE software package, which uses a supply voltage of 0.9 V at a frequency of 20 kHz. The time series, frequency spectra, transitions in phase space, sensitivity with the initial condition diagrams, and bifurcation phenomena are presented. The main advantage of this circuit is that its chaotic signal can be generated while dissipating approximately 7.8 μW of power, making it suitable for embedded systems where many chaos-signal generators are required on a single chip.

关键词： chaos generator carbon nanotube field-effect transistor bifurcation random noise generator

Strong limit on Δα/α from the analysis of feII absorp-tion line multiplets

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Natural Science 2011年第7期3卷 508-512页

作者： Le Duc Thong nguyen thi thu Huong 不详

The article has been retracted due to the investigation of complaints received against it. The substantial portions of the text came from Le Duc Thong’s former article, 'New method of searching for cos-mological time variation of the fine-structure constant', which has also been retraced by Prog. Theor. Phys. because of plagiarism. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. this paper published in Vol.3 No.7 508-512, 2011, has been removed from this site.

关键词： Determination of Fundamental Constants Observation Cosmology

New test for cosmological time variation of thefine-structure constant from the analysis of quasarspectra

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Natural Science 2011年第7期3卷 503-507页

作者： Le Duc Thong nguyen thi thu Huong 不详

The article has been retracted due to the investigation of complaints received against it. The substantial portions of the text came from Le Duc Thong’s former article, 'New method of searching for cos-mological time variation of the fine-structure constant', which has also been retraced by Prog. Theor. Phys. because of plagiarism. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. this paper published in Vol.3 No.7 503-507, 2011, has been removed from this site.

关键词： Determination of FundamentalConstants Observation Cosmology

基于地球化学和环境磁学特征的越南红河沉积物重金属污染研究

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基于地球化学和环境磁学特征的越南红河沉积物重金属污染研究

作者： nguyen thi thu HIEN 华东师范大学

学位级别：硕士

河流重金属污染由于其具有的潜在危害性而受到广泛的关注,重金属含量则常被用作判别河流水环境质量的重要指标。红河是越南第二大河流,但目前对红河沉积物的重金属污染研究仍很薄弱。论文以越南境内红河上游(老街)至河口、水下三角洲采... 详细信息

河流重金属污染由于其具有的潜在危害性而受到广泛的关注,重金属含量则常被用作判别河流水环境质量的重要指标。红河是越南第二大河流,但目前对红河沉积物的重金属污染研究仍很薄弱。论文以越南境内红河上游(老街)至河口、水下三角洲采集的50个表层沉积物为对象,对其进行了粒度、重金属、常量元素地球化学组成和磁性特征的表征,旨在评价重金属污染及其空间变化,分析其影响因素,并探讨磁性特征指示沉积物重金属污染的可行性及其内在关联机制。主要结论如下：1、自红河上游至三角洲平原地区,沉积物粒度呈现先变粗后变细的特征。水下三角洲中,水深5m以浅区域中沉积物以砂质组分占主导,而水深5 m以深区域则主要为粉砂和黏土主导。沉积物粒度特征变化反映了不同沉积环境的水动力强弱。2、根据聚类分析与主成分分析等结果,红河流域沉积物中重金属(Cr、 V、Cu、Cd、Pb、Ni和Zn)可分为两组。其中Cr、V与黏土、Al、Fe、Mn和有机碳(TOC)含量高度相关,表明这些重金属主要富集在富含Fe/Mn氧化物黏土矿物以及有机碳的细颗粒沉积物主要来自自然地风化过程。Cr和V从上游到河口地区逐渐增加,特别是自F39采样点(F39为三角洲河流分汉之处)向河口地区增加趋势尤为明显,反映了粒度对其含量的控制作用,这些因素主要来自自然的风化过程。而Cu、Cd、Pb、Ni和Zn与粒度的关系较弱,其含量自上游向下游无明显变化趋势,这些元素含量在红河上游局部地区呈现高值,说明存在人为污染的影响。3、根据富集因子(EF)计算结果,发现红河沉积物自上游至下游均存在一定程度的重金属污染,其中上游地区污染程度较高。红河沉积物中Cd、Cu和Pb是最主要的重金属污染元素,达到了中度和高度污染水平。4、红河沉积物磁化率x和饱和等温剩磁SIRM有相似的变化趋势,表明红河沉积物的磁性特征为亚铁磁性矿物所主导。磁铁矿和赤铁矿是主要的磁性矿物。粒度是影响沉积物磁性特征的重要因素。χfd%、χARM、χARM/χ、χARM/SIRM与<4μm(黏土)粒级含量之间呈显著正相关;S-ratio与黏土含量呈负相关,表明细晶粒磁铁矿(SP/SD)以及赤铁矿在黏土中富集。自红河上游至河口以及水下三角洲地区,随着黏土含量的增加,磁性颗粒变细,体现了沉积物磁性特征对粒度以及水动力变化的响应。磁性参数χfd%、χARM、χARM/χ、χARM/SIRM可以作为黏土含量的代用指标。5、红河沉积物中未发现磁化率x与重金属含量之间存在明显相关性,这可能指示了磁性矿物与重金属具有不同的来源。磁性参数xfd%与重金属Cr、V、Ni、Zn具有显著的相关性,尤其与Cr和V具有较强的相关性,但与Cu与Cd不具有明显相关性。Cr和V主要来自于自然风化过程,其含量受到粒度特征的控制。由于细粒级组分中较高含量的黏土矿物和铁氧化物对重金属元素具有较强的吸附能力,从而导致了xfd%与Cr、V含量的强相关性。相反,Cu与Cd主要来自于人类活动的污染物质排放,其含量受到粒度的控制作用相对较小,从而导致其与xfd%不具有相关性。Ni、Zn和Pb的含量受到自然风化过程和人类污染活动的双重影响,其与xfd%的相关性程度低于Cr和V,但高于Cu与Cd。因此,在红河沉积物中可将xfd%作为黏土含量的指示指标,并可应用于重金属含量的粒度校正。

关键词：重金属污染磁性特征河流沉积物红河

Assessment of the Irrigation Capacity during the Dry Season Using Remote Sensing and Geographical Information (Case Study in the Binh thuan Province, Vietnam)

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International Journal of Geosciences 2015年第11期6卷 1214-1220页

作者： Hien thi thu Le Thang nguyen Ngoc Luc Hens Institute of Geography Vietnam Academy of Science and Technology (IG/VAST) Hanoi Vietnam Flemish Institute for Technological Research (VITO) Antwerp Belgium

Today satellite system provides a main instrument supplying regular data on land inventory and monitoring of land use/land cover changes, in a timely manner. These data are keys to many applications in different sectors: environment, forestry, hydrology, irrigation, agriculture, geology, resource management and planning. Using Landsat image and change detection, this paper presents a method to extract changes of agricultural land, as the basis for the assessment and development of irrigation systems, which enhance production and protect land resources. During the period 1996-2014, the agricultural land in Binh thuan decreased from 43.5% (in 1996) to 40.1% (February, 2014) of the total land surface in the province. However, the land area under cultivation tends to decrease rapidly, from 25.7% in 1996 to 14.0% in 2014. Combining the results of land use change and assessing the capacity of the irrigation systems show which areas are frequently irrigated versus those are not. this allows proposing irrigation development needs contributing to more production while protecting land resources.

关键词： Land Use Change Irrigation Landsat Vietnam

Estimation of Waste Generation and Recycling Potential from Traditional Market: A Case Study in Hue City, Vietnam

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Journal of Environmental Protection 2015年第4期6卷 308-320页

作者： Yasuhiro Matsui Do thi thu Trang nguyen Phuc Thanh Graduate School of Environmental and Life Science Okayama University Okayama Japan Hitachi Zosen Corp Osaka Japan

this study was conducted to provide a detailed description of waste generation and characteristics from a traditional market in Hue city, located in central Vietnam. The authors conducted a waste generation survey and a waste composition survey for 309 stalls/vendors in five markets by 17 business categories for 10 consecutive days. The waste generation rates by stall/vendor and by floor area were assessed in three waste categories: general waste, recyclable, and food residues. The general waste that would be sent to a landfill site was classified into 10 physical categories and 77 sub-categories. For general waste, food waste accounted for the largest part, followed by plastic and grass. By multiplying the waste generation rate by stall/vendor by the total number of stall/vendors in 23 markets, the authors estimated the total amounts of general waste, recyclable, food residue and total waste by business category. The total waste generated from market was 17.0 tons/day, of which 4.6 tons (27.1%) were collected by pig farmers for feeding livestock and 0.6 tons (3.6%) were sold to the recycling market. The composting potential accounted for 55.2% of total waste generation from the traditional market in Hue. The recycling potential accounted for 5.1%. The total disposal amount sent to the landfill site would be reduced from 69.2% to 8.8% of the total. The 95% confidence interval (CI) of total waste amount from 23 markets was also estimated using Monte Carlo simulation based on the mean and standard error of the waste generation rate. The range of 95% CI was 14.9 - 18.9 tons/day.

关键词： Traditional Market Recycling Potential Composting Potential

Consequence of shape elongation on emission asymmetry for colloidal CdSe/CdS nanoplatelets

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Nano Research 2018年第7期11卷 3593-3602页

作者： Fu Fengt Loan thu nguyen Michel Nasilowski Brice Nadal Benoit Dubertret Laurent Coolent Agnes Maitre Sorbonne Universites UPMC Univ Paris 06 CNRS-UMR 7588 Institut des NanoSciences de Paris F-75005 Paris France Institute of Materials Science Vietnam Academy of Science and Technology 18 Hoang Quoc Viet Road Cau Giay Dist. 100000 Hanoi Vietnam Laboratoire de Physique et d'Etude des Materiaux ESPCI UPMC Univ Paris 6 CNRS 10 rue Vauquelin F-75005 Paris France

In this paper, we demonstrate that for colloidal CdSe/CdS nanoplatelets, a rectangular shape induces emission asymmetry, in terms of both polarization and emission patterns. Polarimetry and emission pattern analyses are combined to provide information on the orientation of the transition dipoles involved in the nanoplatelet emission. It is shown that for rectangular nanoplatelets, the emission is polarized and the emission patterns are anisotropic, whereas they remain nonpolarized and isotropic for square nanoplatelets. this can be appropriately described by the dielectric antenna effect induced by the elongated shape of the rectangular platelet.

关键词： colloidal semiconductor nanoplatelet emission dipole emission polarization emission pattern

Study on Extraction and Conversion Annatto （Bixa orellana L.） Color into Norbixin to Prepare Food Grade Water-Soluble Norbixin Powder

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Journal of Life Sciences 2017年第2期11卷 97-104页

作者： Tran thi ha Dao Phan Thoai Le thi thu thuy Phan The Dong The Department of Food- Environment & Nursing Dong Nai Technology University Dong Nai 810000 Viet Nam The Faculty of Science & Engineering Hoa Sen University Ho Chi Minh 700000 Viet Nam

Response surface methodology was used in this research to optimize the technical parameters of the extraction and conversion color compound in armatto seeds into norbixin. Parameters affected the extraction efficiency and norbixin recovery yield were solvent concentration, rate of solvent/seed, incubation time, and incubation temperature. The optimization results including： concentration of ethanol is 51.82°; concentration of NaOH is 0.52 M; ratio of solvent/seed is 7.1/1; incubation time is 33.12 minutes, incubation temperature is 58.6℃, and the rate of 36% HCl/color solution is 0.5/5 （v/v）.

关键词： Achiote Bixa orellana L. bixin norbixin extraction conversion food color.

Effect of land use change on water discharge in Srepok watershed,Central Highland,Viet Nam

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International Soil and Water Conservation Research 2014年第3期2卷 74-86页

作者： nguyen thi Ngoc Quyen nguyen Duy Liem nguyen Kim Loi Tay nguyen University Viet Nam.567 Le Duan streetBuon Ma Thuot CityDak Lak Province Nong Lam University Viet Nam.Linh Trung WardThu Duc districtHo Chi Minh City

Srepok watershed plays an important role in Central Highland in Viet *** impacts to developing social-economic ***,it is necessary to research elements which impact to natural resources in this *** Soil and Water Assessment Tool(SWAT)model and Geography Information System(GIS)were used to simulate water discharge in the Srepok *** objectives of the research were to apply GIS and SWAT model for simulation water discharge and then,we assessed land use change which impacted on water discharge in the *** observed stream flow data from Ban Don Stream gauge station was used to calibrate for the period from 1981 to 2000 and then validate for the period from 2001 to *** using SWAT-CUP software to calibration,NSI reached 0.63 and R square value achieved 0.64 from 2004 to 2008 in calibration and NSI gained good level at 0.74 and R square got 0.75 from 2009 to 2012 in validation step at Ban Don *** that,land cover in 2010 was processed like land cover in 2000 and set up SWAT model *** simulated water discharge in scenario 1(land use 2000)was compared with scenario 2(land use 2010),the simulation result was not significant difference between two scenarios because the change of area of land use was not much enough to affect the fluctuation of water ***,the effect of land cover on water resource could be seen clearly via total water *** percentage of surface flow in 2000 was twice times more than in 2010;retard and base flow in 2000 was slightly more than in ***,decreased surface flow,increased infiltration capacity of water and enriched base flow resulted in the growth of land cover.

关键词： Water discharge Land use change GIS SWAT model Simulations