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渗氮表面磨削工艺优化研究
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作者 孙维民 《现代制造技术与装备》 2025年第3期118-120,共3页
40CrNiMoA材料经过渗氮处理后,由于渗氮表面脆性大,在后续加工过程中容易产生磨削裂纹,进而出现产品质量问题。基于此,以材质为40CrNiMoA的某轴类零件为例,分析磨削裂纹产生的原因,并提出改进加工设备、优化冷却方式、控制加工参数以及... 40CrNiMoA材料经过渗氮处理后,由于渗氮表面脆性大,在后续加工过程中容易产生磨削裂纹,进而出现产品质量问题。基于此,以材质为40CrNiMoA的某轴类零件为例,分析磨削裂纹产生的原因,并提出改进加工设备、优化冷却方式、控制加工参数以及调整工艺路线等优化和改进措施。经过批生产验证,优化后的磨削工艺方案能够使产品合格率提升至95%。 展开更多
关键词 40CrNiMoA 渗氮表面 磨削裂纹 磨削工艺
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Exploring Malnutrition Risk among Infants under Five Years in Guéra Province, Chad: A Cross-Sectional Study
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作者 Nassaradine Macki Minawir Donatien Serge Mbaga +2 位作者 Mahamat Béchir Bernard Sodio Alpha Seydou Yaro 《Food and Nutrition Sciences》 2025年第1期95-119,共25页
Background: Malnutrition, a serious public health concern, is influenced by various factors. Objective: The study aims to explore malnutrition issues among infants under five years old in Guéra Province. Methods:... Background: Malnutrition, a serious public health concern, is influenced by various factors. Objective: The study aims to explore malnutrition issues among infants under five years old in Guéra Province. Methods: The study used a cross-sectional design and a two-stage cluster sampling method to select participants. The study population was infants aged between 0 - 24 months. Data collection was done between June 2023 and September 2024;it included anthropometric measurements, blood analyses, and interviews. Anthropometric parameters were calculated using ENA for SMART software. Statistical analyses were performed by R Studio to investigate associations between different characteristics, using logistic regression models to identify risk factors. A p-value less than 0.05 was considered significant. Results: The study included 377 infants in eight villages in Guéra Province, Chad. The sample was predominantly girls (55.3%), with a median age of 16 months. Most infants (94%) were mixed-fed, and only 6% were exclusively breastfed. We found that 7.3% of children were globally malnourished, with higher rates in boys 9.6%. A significant disparity existed between boys and girls in global acute malnutrition (GAM) rates, with boys having a higher prevalence of 17.9%. A substantial proportion of Infants were underweight, with males 27.4%. Stunting was prevalent 20.1%. Several factors were associated with malnutrition, including gender, feeding practices, infectious diseases, and socioeconomic factors. Diarrhea, malaria, limited access to drinking water, and early diet diversification were significantly associated with malnutrition. Conclusion: Targeted interventions are necessary to address these issues and improve the nutritional status of children in the Guéra province. 展开更多
关键词 MALNUTRITION UNDERNUTRITION OVERNUTRITION STUNTING WASTING Infant
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Single Sign-On Security and Privacy:A Systematic Literature Review
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作者 Abdelhadi Zineddine Yousra Belfaik +2 位作者 Abdeslam Rehaimi Yassine Sadqi Said Safi 《Computers, Materials & Continua》 2025年第9期4019-4054,共36页
With the proliferation of online services and applications,adopting Single Sign-On(SSO)mechanisms has become increasingly prevalent.SSO enables users to authenticate once and gain access to multiple services,eliminati... With the proliferation of online services and applications,adopting Single Sign-On(SSO)mechanisms has become increasingly prevalent.SSO enables users to authenticate once and gain access to multiple services,eliminating the need to provide their credentials repeatedly.However,this convenience raises concerns about user security and privacy.The increasing reliance on SSO and its potential risks make it imperative to comprehensively review the various SSO security and privacy threats,identify gaps in existing systems,and explore effective mitigation solutions.This need motivated the first systematic literature review(SLR)of SSO security and privacy,conducted in this paper.The SLR is performed based on rigorous structured research methodology with specific inclusion/exclusion criteria and focuses specifically on the Web environment.Furthermore,it encompasses a meticulous examination and thematic synthesis of 88 relevant publications selected out of 2315 journal articles and conference/proceeding papers published between 2017 and 2024 from reputable academic databases.The SLR highlights critical security and privacy threats relating to SSO systems,reveals significant gaps in existing countermeasures,and emphasizes the need for more comprehensive protection mechanisms.The findings of this SLR will serve as an invaluable resource for scientists and developers interested in enhancing the security and privacy preservation of SSO and designing more efficient and robust SSO systems,thus contributing to the development of the authentication technologies field. 展开更多
关键词 Single sign-on AUTHENTICATION OAuth2.0 OpenID connect security PRIVACY mitigation solutions
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Impact of Pyrolysis Parameters on Biochar and Activated Carbon Properties from Cistus ladaniferus for Environmental Applications
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作者 Hammadi El Farissi Anass Choukoud +2 位作者 Bouchaib Manoun Mohamed El Massaoudi Abdelmonaem Talhaoui 《Journal of Renewable Materials》 2025年第6期1251-1266,共16页
In light of the growing urgency to address environmental degradation and improve carbon sequestration strategies,this study rigorously investigates the potential of Cistus ladaniferus as a viable feedstock for biochar... In light of the growing urgency to address environmental degradation and improve carbon sequestration strategies,this study rigorously investigates the potential of Cistus ladaniferus as a viable feedstock for biochar and activated carbon production.The influence of pyrolysis temperature,heating rate and particle size on biochar yield was systematically examined.The results demonstrate that increasing pyrolysis temperature and heating rate significantly reduces biochar yield,while particle size plays a crucial role in thermal degradation and biochar retention.To evaluate the structural and chemical properties of the materials,various characterization techniques were employed,including Fourier-transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM),and energy-dispersive X-ray analysis(EDXA).FTIR identified key functional groups,while SEM and EDXA provided valuable insights into the morphology and elemental composition of the materials.Activated carbons exhibited enhanced porosity and carbon content compared to their biochar counterparts,achieving specific surface areas of up to 1210 m^(2) g^(-1) for acidactivated shells(AC-Sha).The Brunauer-Emmett-Teller(BET)method confirmed the mesoporous characteristics of these materials,with AC-Sa displaying a surface area of 678.74 m^(2) g^(-1) and an average pore size of 2.73 nm.Elemental analysis revealed that activated carbons possessed a higher carbon content(96.40 wt.%for AC-Sha)and lower oxygen content(2.37 wt.%),highlighting their suitability for applications in adsorption and catalysis.These findings underscore the significant impact of activation processes on the stability and adsorption capabilities of Cistus-derived biochars and activated carbons,paving the way for future research and practical applications in pollution control,carbon sequestration,and bioenergy. 展开更多
关键词 Biomass conversion thermal process heating rate SHELLS SEEDS BET adsorption ECO-FRIENDLY
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Large magnetocaloric effect and magnetic properties of EuRhO_(3) 被引量:1
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作者 M.Lassri M.Sajieddine +3 位作者 A.Elouafi A.El Hachmi S.El Ouahbi R.Moubah 《Journal of Rare Earths》 SCIE EI CAS CSCD 2024年第9期1724-1729,I0004,共7页
We report on the structural,magnetic,and magnetocaloric properties of EuRhO_(3) powders.The oxidation states of Eu and Rh ions were studied using X-ray photoelectron spectroscopy(XPS).It is found that the Eu ions are ... We report on the structural,magnetic,and magnetocaloric properties of EuRhO_(3) powders.The oxidation states of Eu and Rh ions were studied using X-ray photoelectron spectroscopy(XPS).It is found that the Eu ions are mainly in the divalent oxidation state while the Rh ions have+4 state.EuRhO_(3) powders are found to be antiferromagnetic with a second order magnetic transition at Neel temperature(T_(N)=2.9 K).Analysis of the magnetic susceptibility versus temperature data in terms of the Curie=Weiss law:(χ=C/(T-θ_(W))) for T>T_(N),yields θ_(W)=-3.1 K and effective magne tic moment μ_(ff)^(exp),which is close to the theoretical value μ_(eff)^(theo).The magnetic entropy change(-Δ_(SM)),was determined by em ploying the thermodynam ic Maxwell's relation.At μ_0H=5 T and near T_(N),ΔS_(M)^(Max) and relative cooling power(RCP) exhibit large values of 33.7 J/(kg·K) and 238 J/kg,respectively.The large magnitude of-Δ_(SM) and RCP show that the EuRhO_(3) compound could be a potential candidate to be used in cryogenic magnetic refrigeration. 展开更多
关键词 X-ray photoelectron spectroscopy Cryogenic magnetic refrigeration Magnetic properties Magnetocaloric effect Rare earths
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低压涡轮转子WFL车铣复合加工工艺研究 被引量:1
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作者 孙维民 《现代制造技术与装备》 2024年第5期121-123,共3页
针对低压涡轮转子现存问题,在数控加工工艺性分析的基础上,对车铣复合数控加工关键技术进行相关研究。首先,对低压涡轮转子的工艺性进行分析;其次,研究加工中的难点;最后,对于加工中出现的问题给出相应的解决方案,包括程序优化、工装改... 针对低压涡轮转子现存问题,在数控加工工艺性分析的基础上,对车铣复合数控加工关键技术进行相关研究。首先,对低压涡轮转子的工艺性进行分析;其次,研究加工中的难点;最后,对于加工中出现的问题给出相应的解决方案,包括程序优化、工装改进、机加工过程中的变形控制等,以期为相关人员提供参考与借鉴。 展开更多
关键词 低压涡轮转子 车铣复合加工 工艺研究
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A NOVEL STOCHASTIC HEPATITIS B VIRUS EPIDEMIC MODEL WITH SECOND-ORDER MULTIPLICATIVE α-STABLE NOISE AND REAL DATA
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作者 Anwarud DIN Yassine SABBAR 吴鹏 《Acta Mathematica Scientia》 SCIE CSCD 2024年第2期752-788,共37页
This work presents an advanced and detailed analysis of the mechanisms of hepatitis B virus(HBV)propagation in an environment characterized by variability and stochas-ticity.Based on some biological features of the vi... This work presents an advanced and detailed analysis of the mechanisms of hepatitis B virus(HBV)propagation in an environment characterized by variability and stochas-ticity.Based on some biological features of the virus and the assumptions,the corresponding deterministic model is formulated,which takes into consideration the effect of vaccination.This deterministic model is extended to a stochastic framework by considering a new form of disturbance which makes it possible to simulate strong and significant fluctuations.The long-term behaviors of the virus are predicted by using stochastic differential equations with second-order multiplicative α-stable jumps.By developing the assumptions and employing the novel theoretical tools,the threshold parameter responsible for ergodicity(persistence)and extinction is provided.The theoretical results of the current study are validated by numerical simulations and parameters estimation is also performed.Moreover,we obtain the following new interesting findings:(a)in each class,the average time depends on the value ofα;(b)the second-order noise has an inverse effect on the spread of the virus;(c)the shapes of population densities at stationary level quickly changes at certain values of α.The last three conclusions can provide a solid research base for further investigation in the field of biological and ecological modeling. 展开更多
关键词 HBV model nonlinear perturbation probabilistic bifurcation long-run forecast numerical simulation
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Influence of the Nature of the Incoming Sludge on the Performance of a Vertical Flow Reed Beds in Dakar-Senegal
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作者 Elhadji Mamadou Sonko Diomaye Dieng +1 位作者 Maïmouna Lo Cheikh Diop 《Journal of Water Resource and Protection》 CAS 2024年第6期429-449,共21页
This work investigates the influence of the type sludge on drainage, plant development, purification performances and biosolids quality. Drainage properties were measured through the frequency of clogging, the percent... This work investigates the influence of the type sludge on drainage, plant development, purification performances and biosolids quality. Drainage properties were measured through the frequency of clogging, the percentage of leachate recovered and the dryness of accumulated sludge. Plant development was measured through the density, the height and the stem diameter. Purification performance was evaluated from the reduction rate. Biosolids quality was measured after 3 months of maturation. The results show that the clogging frequencies were 9.5%;0% and 3.7%;the volume of leachate recovered was 42.2%;20.4% and 24.7% and, the dryness was 33.4%;61.1% and 52.4% for FS-ST, FS-STT and SS respectively. Plants densities were about, with densities 197.1, 171.3 and 178.3 plants/m2 in beds fed respectively with FS-ST, FS-STT and SS. Despite the high removal rates, the concentrations of pollutants in the leachates are above the Senegalese standard NS 05-061 for discharge into the environment. The biosolids are all mature with C/N and NH4+/NO3?ratios lower than 12 and 1 respectively. The biosolids are also rich in organic and mineral elements. The concentrations of Ascaris eggs are higher than the WHO recommendations. These biosolids should be stored for additional time or composted. 展开更多
关键词 Biosolid Quality Dewatering Performance Planted Drying Beds Purification Performance Sludge Type
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Diversity and Structure of the Woody Stand in a Sudano-Sahelian Transition Zone in Senegal
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作者 Oumar Sarr Moustapha B. Sagna +2 位作者 Amy Bakhoum Sékouna Diatta Aliou Guissé 《Open Journal of Ecology》 2024年第1期1-16,共16页
The main objective of the study was to investigate the diversity of the woody stratum of the vegetation in intercommunity rangelands in the department of Koungheul based on an ecological inventory using vegetation sur... The main objective of the study was to investigate the diversity of the woody stratum of the vegetation in intercommunity rangelands in the department of Koungheul based on an ecological inventory using vegetation surveys. The results indicate a rich flora of 70 species divided into 54 genera and 27 families where Ceasalpiniaceae and Rubiaceae are dominant (5 genera each). They are followed by Combretaceae and Euphorbiacea (4 genera each) and by Capparaceae, Fabaceae and Mimosaceae (3 genera for each family). But at the specific level, it is the Combretaceae which dominates with 10 species and Rubiaceae (7 species). It is more representative at the level of the rural community of Lour Esacale. The different values of vegetation parameters from one site to another indicate variability in community rangeland management practices. The woody stand, dominated by small Combretaceae, shows a relatively stable level of organization with an average equitability of about 45% for the two rural communities studied. Species such as Cordyla pinnata, Sclerocarya birrea, Adansonia digitata and Sterculia setigera contributed strongly to the basal and aerial cover of the overall stand. The regeneration of the stand is very good (about 85% on average) but it represents very few species, especially of the Combretaceae family. This shows a tendency to a progressive loss of species richness in the woody stratum. 展开更多
关键词 FLORA Woody Species Vegetation Surveys REGENERATION Kaffrine Region
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Author Correction to “Enhanced Property of Thin Cuprous Oxide Film Prepared through Green Synthetic Route”
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作者 Achraf El Kasmi Henning Vieker +3 位作者 Ling-nan Wu AndréBeyer Tarik Chafik Zhenyu Tian 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2024年第4期571-571,共1页
This correction adds some information to our publication[Chin.J.Chem.Phys.32,365–372(2019)]that we previously missed to include.Our previous work published in[Appl.Catal.B Env-iron.186,10(2016)]was based on the same ... This correction adds some information to our publication[Chin.J.Chem.Phys.32,365–372(2019)]that we previously missed to include.Our previous work published in[Appl.Catal.B Env-iron.186,10(2016)]was based on the same sample series but with the focus of explaining the interplay between the catalytic behavior and properties of the cuprous thin films.A superior catalytic performance was demonstrated when water was added in the deposition process[1](see Ref.[47]in our publication corrected here). 展开更多
关键词 films. CATALYTIC CORRECTION
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Physicochemical and Bacteriological Profile of Bilanko and Ngamakala Peat Bog Soils (Republic of Congo)
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作者 Gatsé Elgie Viennechie Mboukou Kimbatsa Irène Marie Cecile +2 位作者 Ignoumba Evariste Mesmin Morabandza Cyr Jonas Nguimbi Etienne 《Journal of Environmental Protection》 2024年第8期842-862,共21页
Peatlands are unique and complex natural ecosystems that are part of the most important carbon reservoirs on our planet, home to a diversity of microorganisms responsible for fermentation, humification or peat. The ai... Peatlands are unique and complex natural ecosystems that are part of the most important carbon reservoirs on our planet, home to a diversity of microorganisms responsible for fermentation, humification or peat. The aim is to understand chemical and biological indicators of peatland soils. This work aims to determine the physicochemical and bacteriological profile and lipolytic activity of soil bacteria in Bilanko peatlands. The bacterial profile with the production of lipases is carried out by classical microbiology techniques. The results show that the soils are moderately acidic with temperatures of 27.8˚C ± 0.01˚C for Bilanko and 27.1˚C ± 0.57˚C for Ngamakala. The electroconductivity (EC) varies from (9.52 ± 0.002) μS/cm to (39.01 ± 1.4) μS/cm with low turbidity of (2.04 ± 0.66) mg/L to (31.02 ± 0.84) mg/L and low ion concentrations with, however, a richness in phenolic compounds for Bilanko compared to Ngamakala. FMAT diversity ranged from (1.71 ± 0.88)∙104 UFC/g to (2.92 ± 0.07)∙105 UFC/g for Bilanko and (1.30 ± 0.73)∙104 UFC/g to (2.89 ± 0.06)∙104 UFC/g for Ngamakala. Bacillus loads ranged from (5.20 ± 1.40)∙103 CFU/g to (1.22 ± 0.13)∙104 CFU/g and from (1.11 ± 0.13)∙104 CFU/g to (9.20 ± 2.05)∙103 CFU/g;enterobacteria loads from (1.40 ± 0.76)∙103 CFU/g to (8.80 ± 1.73)∙103 CFU/g and from (1.01 ± 0.02)∙103 CFU/g to (9.20 ± 2.05)∙103 CFU/g;in Pseudomonas from 0 to (2.30 ± 0.53)∙102 CFU/g and from 0 to (8.90 ± 2.35)∙102 CFU/g for Bilanko and Ngamakala respectively. These results reveal a variation in bacterial similarity and distribution in the Bilanko and Ngamakala peat bogs. 展开更多
关键词 BACTERIA LIPASE POLYPHENOL Soil Peat Bog Republic of Congo
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Seasonal Performance of Solar Power Plants in the Sahel Region: A Study in Senegal, West Africa
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作者 Serigne Abdoul Aziz Niang Mamadou Simina Drame +4 位作者 Astou Sarr Mame Diarra Toure Ahmed Gueye Seydina Oumar Ndiaye Kharouna Talla 《Smart Grid and Renewable Energy》 2024年第2期79-97,共19页
The main objective of this study is to evaluate the seasonal performance of 20 MW solar power plants in Senegal. The analysis revealed notable seasonal variations in the performance of all stations. The most significa... The main objective of this study is to evaluate the seasonal performance of 20 MW solar power plants in Senegal. The analysis revealed notable seasonal variations in the performance of all stations. The most significant yields are recorded in spring, autumn and winter, with values ranging from 5 to 7.51 kWh/kWp/day for the reference yield and 4.02 to 7.58 kWh/kWp/day for the final yield. These fluctuations are associated with intense solar activity during the dry season and clear skies, indicating peak production. Conversely, minimum values are recorded during the rainy season from June to September, with a final yield of 3.86 kWh/kW/day due to dust, clouds and high temperatures. The performance ratio analysis shows seasonal dynamics throughout the year with rates ranging from 77.40% to 95.79%, reinforcing reliability and optimal utilization of installed capacity. The results of the capacity factor vary significantly, with March, April, May, and sometimes October standing out as periods of optimal performance, with 16% for Kahone, 16% for Bokhol, 18% for Malicounda and 23% for Sakal. Total losses from solar power plants show similar seasonal trends standing out for high loss levels from June to July, reaching up to 3.35 kWh/kWp/day in June. However, using solar trackers at Sakal has increased production by up to 25%, demonstrating the operational stability of this innovative technology compared with the plants fixed panel. Finally, comparing these results with international studies confirms the outstanding efficiency of Senegalese solar power plants, other installations around the world. 展开更多
关键词 Performance Study Photovoltaic Power Plant Season Variations Senegal
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<i>In-Vitro</i>Fermentation by Human Fecal Bacteria and Bile Salts Binding Capacity of Physical Modified Defatted Rice Bran Dietary Fiber 被引量:11
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作者 Cheickna Daou Hui Zhang +1 位作者 Camel Lagnika Oumarou Hama Moutaleb 《Food and Nutrition Sciences》 2014年第12期1114-1120,共7页
Defatted rice bran dietary fiber (DRBDF) was modified by micronization, ultrasound, microwave and extrusion cooking. We investigated the impacts of these physical treatments on the fermentation ability and bile salts ... Defatted rice bran dietary fiber (DRBDF) was modified by micronization, ultrasound, microwave and extrusion cooking. We investigated the impacts of these physical treatments on the fermentation ability and bile salts binding capacity of DRBDF. In-vitro fermentation by human fecal bacteria of modified fibers showed that the major fermentation products were propionic, acetate and butyrate acid. Fermentation of extruded fiber gave the highest amounts of propionic and acetic acid 135.76 and 25.45 mmol/L respectively, while, the fermented product with microwaved fiber had the highest butyric acid content (10.75 mmol/L). The amount of short-chain fatty acid increased from 12 h to 24 h and propionic acid was the predominant. On the other hand,in-vitrobile salts binding showed that extruded fiber had higher affinity with sodium deoxycholate and sodium chenodeoxycholate (66.14% and 30.25% respectively) while microwaved fiber exhibited the highest affinity with sodium taurocholate (14.38%). In the light of obtained results we can affirmed that these physical treatments significantly improved the fermentation products and bile salts binding capacity of DRBDF. Extrusion compared to the other physical treatment methods used in this study has greatly and positively influenced the fermentation and bile binding capacity of DRBDF. 展开更多
关键词 Defatted Rice Bran DIETARY FIBER PHYSICAL Treatments MODIFIED DIETARY FIBER FERMENTATION Bile Salts Binding
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A comparative study of digital low dropout regulators 被引量:2
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作者 Mo Huang Yan Lu Rui P.Martins 《Journal of Semiconductors》 EI CAS CSCD 2020年第11期52-60,共9页
Granular power management in a power-efficient system on a chip(SoC)requires multiple integrated voltage regulators with a small area,process scalability,and low supply voltage.Conventional on-chip analog low-dropout ... Granular power management in a power-efficient system on a chip(SoC)requires multiple integrated voltage regulators with a small area,process scalability,and low supply voltage.Conventional on-chip analog low-dropout regulators(ALDOs)can hardly meet these requirements,while digital LDOs(DLDOs)are good alternatives.However,the conventional DLDO,with synchronous control,has inherently slow transient response limited by the power-speed trade-off.Meanwhile,it has a poor power supply rejection(PSR),because the fully turned-on power switches in DLDO are vulnerable to power supply ripples.In this comparative study on DLDOs,first,we compare the pros and cons between ALDO and DLDO in general.Then,we summarize the recent DLDO advanced techniques for fast transient response and PSR enhancement.Finally,we discuss the design trends and possible directions of DLDO. 展开更多
关键词 low dropout regulator(LDO) digital control fast transient response power supply rejection(PSR) integrated voltage regulator
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Illumination Level Effects on Macroscopic Parameters of a Bifacial Solar Cell 被引量:2
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作者 Nzonzolo   D. Lilonga-Boyenga G. Sissoko 《Energy and Power Engineering》 2014年第3期25-36,共12页
This study presents a method based on the experimental measurement of the short-circuit current (Icc) and the open circuit voltage (Vco) of the solar cell. It permits the determination of recombination parameters such... This study presents a method based on the experimental measurement of the short-circuit current (Icc) and the open circuit voltage (Vco) of the solar cell. It permits the determination of recombination parameters such as: diffusion length (L), back surface recombination velocity (Sb), intrinsic junction recombination velocity (Sjo), and macroscopic parameters in particular, the shunt and series resistances of a bifacial solar cell for various illumination levels (n). Illumination level effects on macroscopic parameters are highlighted. 展开更多
关键词 Solar Cell Photo VOLTAGE Recombination VELOCITY Diffusion LENGTH Series RESISTANCE SHUNT RESISTANCE
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Enhanced Property of Thin Cuprous Oxide Film Prepared through Green Synthetic Route 被引量:2
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作者 Ling-nan Wu Zhen-yu Tian 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第3期365-372,I0002,共9页
Thin cuprous oxide films have been prepared by chemical vapor deposition(pulsed spray evaporation-chemical vapor deposition)method without post-treatment.The synthesis of cuprous oxide was produced by applying a water... Thin cuprous oxide films have been prepared by chemical vapor deposition(pulsed spray evaporation-chemical vapor deposition)method without post-treatment.The synthesis of cuprous oxide was produced by applying a water strategy effect.Then,the effect of water on the morphology,topology,structure,optical properties and surface composition of the obtained films has been comprehensively investigated.The results reveal that a pure phase of Cu2O was obtained.The introduction of a small quantity of water in the liquid feedstock lowers the band gap energy from 2.16 eV to 2.04 eV.This finding was mainly related to the decrease of crystallite size due to the effect of water.The topology analyses,by using atomic force microscope,also revealed that surface roughness decreases with water addition,namely more uniform covered surface.Moreover,theoretical calculations based on density functional theory method were performed to understand the adsorption and reaction behaviors of water and ethanol on the Cu2O thin film surface.Formation mechanism of the Cu2O thin film was also suggested and discussed. 展开更多
关键词 Cuprous oxide thin films Pulsed spray evaporation-chemical vapor deposition method Green synthetic route Optical and topology property Band gap Density functional theory calculation
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Influence of Dust Deposition on the Electrical Parameters of Silicon-Based Solar Panels Installed in Senegal (Dakar Region) 被引量:1
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作者 Dialo Diop Moulaye Diagne +3 位作者 Abel Sambou Pascal Djicoly Bassene Serigne Abdoul Aziz Niang Astou Sarr 《Energy and Power Engineering》 2021年第5期174-189,共16页
In recent years, photovoltaic (PV) modules are widely used in many applications around the world. However, this renewable energy is plagued by dust, airborne particles, humidity<span style="font-family:Verdana... In recent years, photovoltaic (PV) modules are widely used in many applications around the world. However, this renewable energy is plagued by dust, airborne particles, humidity<span style="font-family:Verdana;">,</span><span style="font-family:Verdana;"> and high ambient temperatures. This paper studies the effect of dust soiling on silicon-based photovoltaic panel performance in a mini-solar power plant located in Dakar (Senegal, 14<span style="white-space:nowrap;">&deg;</span>42'N latitude, 17<span style="white-space:nowrap;">&deg;</span>28'W longitude). Results of the current</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">voltage (I - V) characteristics of photovoltaic panels tested under real conditions. We modeled a silicon-based PV cell in a dusty environment as a stack of thin layers of dust, glass and silicon. </span><span style="font-family:Verdana;">The </span><span style="font-family:;" "=""><span style="font-family:Verdana;">silicon layer is modeled as a P-N junction. The study performed under standard laboratory conditions with input data of irradiation at 1000 W/m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">, cell temperature at 25<span style="white-space:nowrap;">&deg;</span>C and solar spectrum with Air Mass (AM) at 1.5 for the monocrystalline silicon PV cell (m-Si). The analysis with an ellipsometer of dust samples collected on photovoltaic panels allowed to obtain the refraction indices (real and imaginary) of these particles which will complete the input parameters of the model. Results show that for a photon flux arriving on dust layer of 70 μm (corresponding to dust deposit of 3.3 g/m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">) deposited on silicon-based PV cell</span></span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;">, short circuit current decreases from 54 mA (for a clean cell) to 26 mA. Also, conversion efficiency decreases by 50% compared </span><span style="font-family:Verdana;">to </span><span style="font-family:Verdana;">clean cell and the cell fill factor decreases by 76% - 50% compared to reference PV cell.</span> 展开更多
关键词 Dust Deposition PV Cell Fill Factor Modeling ELLIPSOMETER
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Using statistical models and GIS to delimit the groundwater recharge potential areas and to estimate the infiltration rate: A case study of Nadhour-Sisseb-El Alem Basin, Tunisia 被引量:1
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作者 Ali SOUEI Taher ZOUAGHI 《Journal of Arid Land》 SCIE CSCD 2021年第11期1122-1141,共20页
The water resources of the Nadhour-Sisseb-El Alem Basin in Tunisia exhibit semi-arid and arid climatic conditions.This induces an excessive pumping of groundwater,which creates drops in water level ranging about 1-2 m... The water resources of the Nadhour-Sisseb-El Alem Basin in Tunisia exhibit semi-arid and arid climatic conditions.This induces an excessive pumping of groundwater,which creates drops in water level ranging about 1-2 m/a.Indeed,these unfavorable conditions require interventions to rationalize integrated management in decision making.The aim of this study is to determine a water recharge index(WRI),delineate the potential groundwater recharge area and estimate the potential groundwater recharge rate based on the integration of statistical models resulted from remote sensing imagery,GIS digital data(e.g.,lithology,soil,runoff),measured artificial recharge data,fuzzy set theory and multi-criteria decision making(MCDM)using the analytical hierarchy process(AHP).Eight factors affecting potential groundwater recharge were determined,namely lithology,soil,slope,topography,land cover/use,runoff,drainage and lineaments.The WRI is between 1.2 and 3.1,which is classified into five classes as poor,weak,moderate,good and very good sites of potential groundwater recharge area.The very good and good classes occupied respectively 27%and 44%of the study area.The potential groundwater recharge rate was 43%of total precipitation.According to the results of the study,river beds are favorable sites for groundwater recharge. 展开更多
关键词 potential recharge remote sensing statistical models MCDM Nadhour-Sisseb-El Alem Basin
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Physicochemical Characterization of Nine Cassava (<i>Manihot esculenta</i>Crantz) Cultivars from Chad 被引量:1
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作者 Djirabaye Nadjiam Nicolas Cyrille Ayessou Aliou Guissé 《Food and Nutrition Sciences》 2020年第7期741-756,共16页
In Chad, despite the multiple culinary uses of cassava leaves and tubers, their nutritional values are untapped. In this study, the physicochemical compositions and structure of nine cultivars were assessed. The prote... In Chad, despite the multiple culinary uses of cassava leaves and tubers, their nutritional values are untapped. In this study, the physicochemical compositions and structure of nine cultivars were assessed. The proteins were obtained by Kjeldahl’s method. Total sugars were determined according to the Luff-Schoorl method. For starch content, the polarimetric method of Earle and Milner was used. Mineral elements were carried out using an atomic absorption spectrophotometry. The cyanide was evaluated by the method of Williams and Edwards. Significant variability has been demonstrated in the leaves and dry tubers except for water content and dry matter. Analysis of the variances of the components of the tubers reveals that the water contents of the cultivars vary from 5.01% to 5.86%. The ash contents vary from 4.23% (cultivar DVA2) to 8.32% (cultivar DVL2). For total sugars, the values are between 53.63% (cultivar DVL2) and 57.99% (cultivars DVL12 and KA0303). The fiber contents are lower and vary from 1.74% (cultivar DVL12) to 1.92% (cultivars SB1366, DVA2, TL0101 and PG1314). The starch content varies from 28.93% (cultivar DVL12) to 31.05% (cultivar SB1366). The variations in mineral constituents of the tubers in mg/100g are Ca (145.21 - 250.08), Mg (83.89 - 165.22), P (147.34 - 360.78), K (1534.50 - 3064.09), Zn (0.75 - 0.82) and Mn (0.78 - 0.89). Iron concentrations are from 7.72 mg/100g (cultivar BA0909) to 60.62 mg/100g (cultivar DVA2</span><span style="font-family:Verdana;">)</span><span style="font-family:""><span style="font-family:Verdana;">. Analysis of the variances of the </span><span style="font-family:Verdana;">leaf constituents reveals high contents of Calcium for SB1366 (2108.41 mg/100g)</span><span style="font-family:Verdana;">, of iron (Fe 54.26 mg/100g) and potassium (K 1866.86 mg/100g) for DVL12, </span><span style="font-family:Verdana;">of phosphorus for TL0101 (471.87 mg/100g), of phosphorus (470.36 mg/100g)</span> <span style="font-family:Verdana;">and protein (30.74%) for PG1314, for magnesium for DVA2 (383.41 mg/100g)</span> <span style="font-family:Verdana;">and Copper for KA0303 (0.0147 mg/100g). The concentrations of hydrocyanic</span><span style="font-family:Verdana;"> acids are high in both leaves than fresh tubers (85 - 150 ppm). Lowest values are observed in tubers (10 - 15 ppm) for cultivar DVA2. Principal component analysis of the physicochemical characteristics of the leaves revealed four groups: the first very rich in calcium, magnesium and average potassium contents. Groups 2 and 3 are poor in calcium and magnesium but Group 2 </span><span style="font-family:Verdana;">ha</span></span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> the highest potassium content while Group 3 ha</span><span style="font-family:Verdana;">s</span><span style="font-family:Verdana;"> an intermediate conten</span><span style="font-family:""><span style="font-family:Verdana;">t. Group 4 is very rich in calcium but low in magnesium and potassium. </span><span style="font-family:Verdana;">According to tubers, three groups have been identified which are characterized</span><span style="font-family:Verdana;"> by low, intermediate </span><span style="font-family:Verdana;">and</span><span style="font-family:Verdana;"> high contents in phosphorus. Cultivars SB1366, DVA2, DVL2, TL0101 an</span><span style="font-family:Verdana;">d PG1314 show promising nutritional values and chemical constituents even if some have high levels of hydrocyanic acids. They could be recommended for the national selection program and for various applications. 展开更多
关键词 Physicochemical Constituents Leaves TUBERS CULTIVAR CASSAVA CHAD
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Functional Results without Correction of Cataract Surgery during a Free Campaign at Siguiri Prefectural Hospital in Guinea 被引量:1
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作者 Pierre Louis Lama Céougna Sagno +4 位作者 Aly Sylla Sidikiba Camara Balla Sovogui Niouma Alexis Ouendeno Oumar Raphiou Diallo 《Open Journal of Ophthalmology》 2022年第3期259-268,共10页
Background: Cataract is the leading cause of blindness in the world and its treatment is exclusively surgical. However, the results of cataract surgery are not always as good as is assumed and this aspect of surgical ... Background: Cataract is the leading cause of blindness in the world and its treatment is exclusively surgical. However, the results of cataract surgery are not always as good as is assumed and this aspect of surgical services needs a lot of attention. The purpose of this study is to evaluate the functional results of the free cataract surgery campaign carried out at the Siguiri Prefectural Hospital in Guinea. Patients and Method: This was a descriptive and retrospective cross-sectional study over a period of three months (1 October-31 December 2017). Records of cataract-operated patients during the study period were reviewed. The complete files for the main variables sought were retained. Sociodemographic data and visual acuity without pre- and post-operative correction were assessed. Functional outcomes were analysed according to WHO guidelines and recommendations for post-operative functional outcomes of cataract surgery. The data was collected and processed using Excel version 2010 software. Results: A total of 108 eyes from 102 patients were the subject of this present study on 314 eyes from 289 operated patients. 64 (%) men and 38 women (%) had a follow-up of 6 weeks after cataract surgery, a sex ratio of 1.68 in favor of women. The average age was 62.45 ± 15.20 years with extremes of 25 and 90 years. The age group from 60 to 69 years is the most represented with 46 cases or 45.45%. Housewives and farmers are the most represented strata with 42 cases (41.18%) and 31 cases (30.39%) respectively. The operative technique was Phaco A in 4/5 of the cases. No implant calculations were performed. Functional results indicate that 66% of patients had good visual acuity (≥3/10);29% of patients had borderline visual acuity (between 1/10 and 2/10) and 13.30% had poor visual acuity (Conclusion: The importance of the rate of poor results in our study should draw our attention to the conduct of free cataract surgery campaigns. The problem of cataract blindness is often compounded by poor outcomes of surgical procedures, especially in low-income settings. The use of biometrics, implants of appropriate power as well as compliance with operative indications, surgical protocols and postoperative follow-up by surgeons will improve the visual result without correction. 展开更多
关键词 CATARACT SURGERY Functional Results CAMPAIGN Siguiri GUINEA
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