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Synthesis of nanostructured zinc oxide and its composite with carbon dots for DSSCs applications using flexible electrode

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Materials Reports(Energy) 2024年第3期4卷 77-83页

作者： Habtamu Fekadu Etefa francis Birhanu Dejene Department of Physics Walter Sisulu UniversityPrivate Bag X-1Mthatha5117South Africa

ZnO nanowires(ZnO NWs),ZnO nanoparticles(ZnO NPs)and carbon dots(C-dots)were synthesized by hydrothermal,sol-gel and hydrothermal methods *** were also characterized and applied for dye sensitized solar cells(DSSCs).The effects of C-dots on ZnO NWs and ZnO NPs have been *** C-dots were used at a mole ratio of citric acid(CA)to ethylene diamine(EDA)of 1:*** C-dots were found to enhance the performance of the flexible electrode *** the addition of C-dots,the power conversion efficiency(PCE)of ZnO NPs was boosted to be two times higher than that of ZnO NPs DSSCs without ***,the ultraviolet(UV)-band revealed a blue shift,resulting in a lower band gap and a reduced charge transfer resistance,which can enhance the PCE of *** loaded quantity on the flexible electrode substrate made of polyethylene terephthalate(PET)was optimized(50 mg).For DSSCs,the PET flexible electrode conductive polymer has produced positive *** ZnO NWs and ZnO NWs@C-dots,the PCE values were 1.45%and 4.25%;while for ZnO NPs and ZnO NPs@C-dots,they were 2.34%and 5.81%,*** work achieved remarkable and competitive performance when compared to solid(indium tin oxides/glass)-based substrate.

关键词： ZnO NWs@C-dots ZnO NPs@C-dots PET DSSCs Flexible electrode

Deterministic approaches for noncoherent communicationswith chaotic carriers

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Journal of Systems Engineering and Electronics 2005年第2期16卷 253-257页

作者： LiuXiongying QiuShuisheng francis.C.M.Lau CollegeofElectronicandInformationEngineering SouthChinaUniversityofTechnologyGuangzhou510640P.R.China DepartmentofElectronicandInformationEngineering HongkongPolytechnicUniversityHongkongP.R.China

Two problems are proposed. The first one is the noise decontamination of chaotic carriers using a deterministic approach to reconstruct pseudo trajectories, the second is the design of communications schemes with chaotic carriers. After presenting our deterministic noise decontamination algorithm, conventional chaos shift keying (CSK) communication system is applied. The difference of Euclidean distance between noisy trajectory and decontaminated trajectory in phase space could be utilized to non-coherently detect the sent symbol simply and effectively. It is shown that this detection method can achieve the bit error rate performance comparable to other non-coherent systems.

关键词： gradient descent reconstruction chaotic communications noncoherent detection.

Impact of a Phosphate Amendment on the Environmental Availability and Phytoavailability of Cd and Pb in Moderately and Highly Carbonated Kitchen Garden Soils

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Pedosphere 2017年第3期27卷 588-605页

作者： Christophe WATERLOT Christelle PRUVOT Franck MAROT francis DOUAY Yncréa Hauts-de-France Laboratoire Génie Civil et géo Environnement (LGCgE) Agence De l’Environnement et de la Matrise de l’Energie (ADEME) Direction Villes et Territoires Durables Services Friches Urbaines et Sites Pollués

The behaviour of metals mainly depends on soil p H, carbonate contents and contamination level, which should be considered for the management of contaminated soils. In this study, kitchen garden topsoils(0–25 cm) were sampled from the area around three smelters in France, with different Cd and Pb contamination levels. Effect of a phosphate amendment(a mixture of diammonium phosphate and hydroxyapatite) on the environmental availability and phytoavailability of Cd and Pb was evaluated by different chemical extractions and cultivating lettuce(Lactuca sativa L.), respectively. Changes in the distribution of Cd and Pb were found in most contaminated soils after phosphate amendment. An increase of Cd and Pb in the residual phase was highlighted in almost all carbonated contaminated soils, whereas a decrease of Pb in the exchangeable, water and acid-soluble phase was observed in most contaminated soils with the lowest carbonate contents. The concentrations of extractable Cd and Pb using calcium chloride and acetic and citric acids generally decreased after the soil amendment. Lettuces grown on amended soils were acceptable for human consumption as regard to Pb concentration. In contrast, some lettuces were unacceptable for human consumption, since the concentrations of Cd in the leaves were higher than the European legislation limit. Surprisingly, in carbonated soils with very low concentration of Cd, the Cd concentrations in lettuce reached up to the European legislation limit, making the lettuce unacceptable for human *** study highlighted the fact that the total metal concentration in soils does not always allow to predict the metal accumulation in the edible parts of vegetables in order to make a judgement about their acceptability or unacceptability for human consumption.

关键词： chemical amendment contamination immobilisation lettuce metal urban soil

Review of applying X-ray computed tomography for imaging soil-root physical and biological processes

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International Journal of Agricultural and Biological Engineering 2015年第5期8卷 1-14页

作者： francis Kumi Mao Hanping Hu Jianping Ikram Ullah Key Laboratory of Modern Agricultural Equipment and Technology Ministry of Education and Jiangsu ProvinceJiangsu UniversityZhenjiang 212013China Department of Agricultural Engineering University of Cape CoastCape CoastGhana

Root growth process in soils has long been a matter of interest to soil and plant *** the opaque nature of the soil has been a barrier to most research attempts aimed at unraveling the full root-soil *** traditional method of separating the roots from the growth media which is common practice tends to be destructive and defeats the purpose of such *** is ineffective in monitoring the interactions within the soil medium and as a result,a fast non-destructive technique is ***,with computing and technological advancements,X-ray computed tomography(CT)has been found to be capable of meeting this need by imaging the processes which are of interest to *** the past three-four decades,the applications of the technology for imaging soil-root studies have attracted the researchers’widespread interests and the future looks more *** purpose of this review is to present an overview of CT applications in imaging root-soil *** main focus is on the use of soil-root interface researches and the way forward for such non-destructive analyses.

关键词： computed tomography soil root imaging non-destructive interactions

Traditional knowledge in HIV/AIDS treatment and prevention program in northern Uganda

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Family Medicine and Community Health 2016年第1期4卷 46-52页

作者： francis Adyanga Akena University of South Africa(UNISA) P.O.Box 3920003

Uganda’s health care sector is choking with various challenges,such as poor physical infrastructure,inadequate professionals to run the few existing health centers,poor culture of adherence to professional ethical standards by some health care practitioners,shortages of medicines in most government hospitals/health centers,and *** of the challenges are more endemic in rural *** is on the above premise that this article discusses some of the challenges that health centers face in provision of care to the increasing number of HIV/AIDS patients in hard-to-reach rural communities in northern Uganda and the implications of such challenges on the ***’s success in the fight against HIV/AIDS in the early 1990s was globally applauded because of its aggressive grassroots behavioral change crusades aimed at reducing the number of sexual *** success inspired a wave of financial aid programs from the US government to fight the disease across the developing ***,the success was short-lived as the rate of HIV/AIDS infection in Uganda is currently rising,with the health care system struggling to provide care for the ballooning number of *** contribute to the curtailing cases of new infections,this article discuses the integration of the traditional authority and knowledge system in the national HIV/AIDS care and prevention program along with the biomedical approach currently being used.

关键词： Traditional knowledge HIV/AIDS interventions professional ethics voluntary medical male circumcision

Aphidophagous guilds on nettle （Urtica dioica） strips close to fields of green pea, rape and wheat

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Insect Science 2007年第5期14卷 419-424页

作者： AMMAR ALHMEDI ERIC HAUBRUGE BERNARD BODSON FREDERIC francis Functional and Evolutionary Entomology Experimental Farm Gembloux Agricultural University Gembloux Belgium

The common nettle （Urtica dioica L.） is a perennial and cosmopolitan plant species and is known to be the source of food for a great diversity of insects. To understand the importance of the nettle in agro-ecosystems, a field experiment was carried out in an experimental farm at Gembloux （Belgium） to study the effect of nettle margin strips on aphid and aphidophagous populations in close field crops, namely wheat （Triticum aestivum L.）, green pea （Pisum sativum L.） and rape （Brassicae napus L.）. The aphids and related beneficial populations were weekly assessed, from March to August 2005, by visual observations in two plots per field crop. A higher abundance of aphidophagous beneficials was collected in nettle strips when compared to the field crops. Particularly, the presence of predatory anthocorids, mirids and green lacewings was observed on nettle only. Nevertheless, the most abundant aphid predatory family, the Coccinellidae, was distributed in both environments, in nettle strips and in crop fields. The field margin supported a significantly higher density ofHarmonia axyridis than the field crops. In contrast, the field crops, green pea particularly, supported a higher density of Coccinella septempunctata. The distribution of the aphidophagous species, mainly the ladybirds, was discussed in relation to the host plant and related aphid species and their potential effect on integrated pest management.

关键词： Aphidophagous ladybirds beneficials insect diversity nettle wheat greenpea rape margin strips integrated pest management Microlophium camosum Acyrthosiphonpisum Sitobion avenae

Comparison of 2-acetylfuran,2-ethylfuran,and 2-methylfuran spherically expanding flame intrinsic instabilities

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Science China(Technological Sciences) 2022年第10期65卷 2388-2398页

作者： XU CangSu WANG QianWen LI XiaoLu OPPONG francis LIU WeiNan College of Energy Engineering State Key Laboratory of Clean Energy UtilizationZhejiang UniversityHangzhou 310027China College of Mechanical and Electrical Engineering Key Laboratory of Intelligent Manufacturing Quality Big Data Tracing and Analysis of Zhejiang ProvinceChina Jiliang UniversityHangzhou 310018China

The intrinsic instability of three furan derivatives, namely, 2-acetylfuran(AF), 2-ethylfuran(EF), and 2-methylfuran(MF), is experimentally and theoretically investigated and compared. A deep-learning-based end-to-end system is used to segment the cells and measure the crack length on the cellular flame front of the spherically expanding flame to quantitively investigate the flame morphology. Moreover, the flame front radius profile is quantitively investigated to shed light on the correlation between disturbance amplitude and flame radius. With the use of the linear stability model, the theoretical critical flame radius and Peclet number are obtained and compared to their corresponding experimental results to characterize the outset of cellularization and evaluate the flame instability propensity. Our analysis shows that compared with AF and EF, MF is prone to cellularization at a smaller flame radius and has a faster cell proliferation rate and crack length growth rate before reaching the hydrodynamic saturation limit. Meanwhile, the average area of saturated cells tends to be similar for the three furan derivatives. Furthermore,AF premixed flame does not exhibit cellularization before the flame radius is less than 45 mm in low initial pressure.

关键词： furan derivatives spherical expanding flame flame intrinsic instability linear stability theory

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Effect of an adverse pressure gradient on the streamwise Reynolds stress profile maxima in a turbulent boundary layer

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Acta Mechanica Sinica 2013年第3期29卷 395-398页

作者： Wei Ma Xavier Ottavy Li-Peng Lu francis Leboeuf Laboratoire de Mécanique des Fluides et d'Acoustique Ecole Centrale de Lyon School of Jet Propulsion Beihang University

It is widely accepted that in a turbulent boundary layer （TBL） with adverse pressure gradient （APG） an outer peak usually appears in the profile of streamwise Reynolds stress. However, the effect of APG on this outer peak is not clearly understood. In this paper, the effect of APG is analysed using the numerical and experimental results in the literature. Because the effect of upstream flow is inherent in the TBL, we first analyse this effect in TBLs with zero pressure gradient on flat plates. Under the individual effect of upstream flow, an outer peak already appears in the profile of streamwise Reynolds stress when the TBL continues developing in the streamwise direction. The APG accelerates the appearance of the outer peak, instead of being a trigger.

关键词： Turbulent boundary layer · Pressure gradient · Reynolds stress

Simulation investigation of tractive energy conservation for a cornering rear-wheel-independent-drive electric vehicle through torque vectoring

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Science China(Technological Sciences) 2018年第2期61卷 257-272页

作者： SUN Wen WANG JunNian WANG QingNian ASSADIAN francis FU Bo State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130022China Department of Mechanical and Aerospace Engineering University of CaliforniaDavisCA 9561USA

Although electric vehicle fully exhibits its comparative merits of energy conservation and environmental friendliness, further improvement of its traction energy efficiency lacks comprehensive investigations in the past. In this paper, the effect of the torque vectoring on traction energy conservation during cornering for a rear-wheel-independent-drive electric vehicle is ***, turning resistance coefficient and energy conservation mechanism of torque vectoring are derived from the single track dynamic model. Next, an optimal torque vectoring control strategy based on genetic algorithm is proposed, with the consideration of the influence of the operation-point change of the in-wheel motors, to find out the best torque vectoring ratio offline. Finally,various simulation tests are conducted to validate the energy conservation effect after Simulink modelling. The results verify that though the optimization of the operating region of the motors is the main part for tractive energy conservation, the contribution of torque vectoring itself can reach up to 1.7% in some typical cases.

关键词： electric vehicle (EV) independent drive cornering resistance torque vectoring energy saving optimization