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malaria prevalence in north-eastern Nigeria:A cross-sectional study Houben ch^(1*),Fleischmann H^2,Gǜckel m^3

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Asian Pacific Journal of Tropical medicine 2013年第11期6卷 865-868页

作者： Houben ch Fleischmann H Gckel m Diagnostic Center mmm group & Specialist Hospital Yola Hospital RoadP.M.B.2266YolaAdamawa.StateNigeria medical mission Institute Tropical MedicineHermann Schell Str 797074 WrzburgGermany Helios Kliniken Schwerin Wismarsche Str 393-39719049 SchwerinGermany

Objective:To assess the prevalence of malaria parasitemia in north-east Nigeria and to evaluate the measures for the prevention of ***:A village in north-eastern Nigeria was selected for the cross sectional study at the height of the rainy season in October 2011.A total of 550 inhabitants of a hamlet were recruited for this *** obtaining the consent individuals received a structured interview and were tested for malaria parasites in their blood *** testing positive for malaria were given a course of artemesinin-based combination therapy（ACT）.Results:A total of 497 inhabitants representing approximately 90 percent of the population participated:a quarter of the study group carried malaria parasitesexclusively Plasmodium falciparum（***）-representing a *** parasite rate（PfPR） of 24.5%.Besides,53/138 in the age group of 2 to children tested positive for *** representing a PfPR2-10 value of 38.4%.malaria control measures were used in just under a third（157/497） of this *** these measures 28/157（17.8%） still tested positive for ***:The malaria burden is overestimated for this region in north-east *** findings support an intermediate pattern of malaria *** 30%bed nets coverage for malaria control is well below the WHO estimates for 2011.

关键词： malaria control malaria endemicity malaria prevalence malaria transmission

Systematic Study of Nanocrystalline Plasma Electrolytic Nitrocarburising of 316L Austenitic Stainless Steel for Corrosion Protection

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Journal of materials Science & Technology 2007年第5期23卷 665-671页

作者： m.Aliofkhazraei P.Taheri A.Sabour Rouhaghdam ch.Dehghanian materials Engineering Department Faculty of EngineeringTarbiat Modares UniversityTehranIran materials Engineering Department Faculty of EngineeringTehran UniversityTehranIran

A number of studies have been reported on the use of nanocrystalline plasma electrolytic nitrocarburising technology for surface hardening of stainless steels for higher corrosion resistance resulted from this technique. However, very few studies have focused on the optimization of the nanocrystalline plasma electrolytic nitrocarburising process parameters. In this study, a design of experiment （DOE） technique, the Taguchi method, has been used to optimize the nanocrystalline plasma electrolytic nitrocarburising not only for surface hardening but also for the corrosion protection of 316L austenitic stainless steel by controlling the coating processes factors. The experimental design consisted of four factors （Urea concentration, electrical conductivity of electrolyte, voltage and duration of process）, each containing three levels. Potentiodynamic polarization measurements were carried out to determine the corrosion resistance of the coated samples. The results were analyzed with related software. An analysis of the mean of signal-to-noise （S/N） ratio indicated that the corrosion resistance of nanocrystalline plasma electrolytic nitrocarburised 316L stainless steel was influenced significantly by the levels in the Taguchi orthogonal array. The optimized coating parameters for corrosion resistance are 1150 g/L for urea concentration, 360 mS/cm for electrical conductivity of electrolyte, 260 V for applied voltage, 6 min for treatment time. The percentage of contribution for each factor was determined by the analysis of variance （ANOVA）. The results showed that the applied voltage is the most significant factor affecting the corrosion resistance of the coatings.

关键词： Nanocrystalline plasma electrolytic nitrocarburising 316L austenitic stainlesssteel Corrosion resistance Potentiodynamic polarization Analysis of variance

Structural and optical properties of CZTS nanoparticles prepared by a colloidal process

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Rare metals 2021年第9期40卷 2602-2609页

作者： R.Aruna-Devi m.Latha S.Velumani JoséÁlvaro chávez-Carvayar Program on Nanoscience and Nanotechnology CINVESTAV-IPNSan Pedro Zacatenco07360 Mexico CityMexico CIICAp-UAEm Av.Universidad 1001.Col.Chamilpa62209 CuernavacaMorelosMexico Department of Electrical Engineering(SEES) CINVESTAV-IPNSan Pedro Zacatenco07360 Mexico CityMexico Instituto de Investigaciones en materiales UNAM04510 Mexico CityMexico

This research presents the influence of copper(Cu) concentration on the properties of copper zinc tin sulfide(CZTS) nanoparticles(NPs) synthesized by a colloidal method, employing oleylamine as an organic solvent. From the structural analysis, a pure phase of CZTS was obtained at an optimized molar ratio of 1.8:1.1:1:4,and secondary phases were observed as the Cu concentration increased. The increment of the NPs size from 15 to50 nm was noticed as a function of Cu ***, the optical bandgap energy was tuned from1.35 to 1.68 eV with respect to Cu concentration. The sample synthesized at the molar ratio of 1.8:1.1:1:4 showed a pure phase CZTS with desired elemental composition and bandgap. Furthermore, CZTS thin films were prepared by a doctor-blade method using synthesized NPs followed by annealing under a sulfur/nitrogen atmosphere. The annealed CZTS film showed a significant improvement in the morphological, electrical and optoelectronic ***, the annealed CZTS film can be efficiently used as an absorber layer in low-cost thin film solar cells.

关键词： CZTS Copper concentration Nanoparticles Thin film Annealing

3D micromechanical modeling of Failure and Damage Evolution in Dual Phase Steel Based on a Real 2D microstructure

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Acta mechanica Solida Sinica 2016年第1期29卷 95-110页

作者： m.R.Ayatollahi A.ch.Darabi H.R.chamani J.Kadkhodapour Fatigue and Fracture Lab. Center of Excellence in Experimental Solid Mechanics and DynamicsSchool of Mechanical EngineeringIran University of Science and Technology

A plate of dual phase steel was produced from low carbon steel with intercritical annealing treatment. Its optically determined surface microstructure was utilized to construct three different microstructural models. To describe the ductile damage in the ferritic matrix, the Gurson-Tvergaard-Needleman model was used with the failure in the martensite phase being ignored. The numerical results obtained for the mechanism of void initiation and coalescence were compared with the experimental observations. The numerical results obtained from the randomly extruded 3D model showed a significantly better agreement with the experimental ones than those obtained from the 2D model or the uniformly extruded 3D model.

关键词： dual phase steel 3D model microstructure micromechanical modeling GTN dam-age model

Polygeneration Study of Low-to-medium Enthalpy Geothermal Reservoirs in mexico

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Journal of Thermal Science 2021年第3期30卷 1077-1087页

作者： chÁVEZ Oscar GODÍNEZ Francisco Tecnológico Nacional de méxico/I.T.chihuahua.Av.Tecnológico 2909 C.P.31310ChihuahuaChihuahuaMéxico Instituto de Ingeniería Universidad Nacional Autónoma de MéxicoUNAMC.U.Ciudad de MéxicoC.P.04510México Polo Universitario de Tecnología Avanzada Universidad Nacional Autónoma de MéxicoVía de la Innovación No.410Autopista Monterrey-Aeropuertokm.10 PIITC.P.66629Apodaca Nuevo LeónMéxico

This study combines the thermodynamic analysis of a polygeneration system along with the numerical modelling of the thermal behavior of geothermal reservoirs in mexico to exploit their *** reservoir was modeled as a porous medium assuming a five-spot well configuration and local thermal *** heat conduction-convection along with the Laplace equations were solved to compute temperature distributions,the useful life and the optimum distance between injection-extraction *** predicted temperature and pressure of the geothermal fluid at the outlet of the reservoir were exploited in the polygeneration system consisting of:(1)a Rankine cycle,(2)an absorption refrigeration cycle,and(3)a heat *** developed approach allows calculating both the optimal distance between injection-extraction wells and the global(utilization)efficiency of six arrangements(each composed by a reservoir connected to a polygeneration system)by assuming that reservoirs have a lifespan of 30 *** also show that:(a)due to the low efficiency of the Rankine cycle,very little thermal energy is converted into electrical one;(b)not only the temperature and the size are important when evaluating the power production performance of reservoirs,but also the permeability plays a fundamental role;(c)the first law efficiency of the polygeneration system ranges from 41.9%to 43.7%;(d)the utilization efficiency of the six arrangements lies in the range between 25.8%and 31%.

关键词： polygeneration system geothermal reservoir local thermal equilibrium low-to-medium enthalpy

Stochastic many-body calculations of moiréstates in twisted bilayer graphene at high pressures

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npj Computational materials 2022年第1期8卷 89-98页

作者： mariya Romanova Vojtěch Vlček Department of chemistry and Biochemistry University of CaliforniaSanta BarbaraCA93106-9510USA

We introduce three developments within the stochastic many-body perturbation theory:efficient evaluation of off-diagonal self-energy terms,construction of Dyson orbitals,and stochastic constrained random phase *** stochastic approaches readily handle systems with thousands of *** use them to explore the electronic states of twisted bilayer graphene(tBLG)characterized by giant unit cells and correlated electronic *** document the formation of electron localization under compression;weakly correlated states are merely shifted in *** demonstrate how to efficiently downfold the correlated subspace on a model Hamiltonian with a screened frequency-dependent two-body *** the 6°tBLG system,the onsite interactions are between 200 and 300 meV under *** Dyson orbitals exhibit spatial distribution similar to the mean-field single-particle *** pressure,the electron-electron interactions increase in the localized states;however,the dynamical screening does not fully balance the dominant bare Coulomb interaction.

关键词： interaction twisted stochastic

Ballistic design and testing of a composite armour reinforced by CNTs suitable for armoured vehicles

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Defence Technology（防务技术） 2024年第2期32卷 173-195页

作者： Evangelos ch.Tsirogiannis Evangelos Daskalakis mohamed H.Hassan Abdalla m.Omar Paulo Bartolo EODH SA Research and Development DepartmentLakkoma Chalkidikis63080Greece School of mechanical Aerospace and Civil EngineeringUniversity of ManchesterManchesterM139PLUK Singapore Centre for 3D Printing School of Mechanical and Aerospace EngineeringNanyang Technological University639798Singapore

This paper is investigating the use of composite armour reinforced by nanomaterials, for the protection of light armoured(LAV) and medium armoured military vehicles(mAV), and the interaction between the composite materials and high-performance ballistic projectiles. Four armour materials, consisted of front hybrid fibre reinforced polymer cover layer, ceramic strike-face, fibre reinforced polymer intermediate layer and the metal matrix composite reinforced backplate, were manufactured and assembled by adhesive technology. The proposed laminated protection system is suitable for armoured ground vehicles;however, it could be used as armour on ground, air and naval platforms. The design of the protection system, including material selection and thickness, was elaborated depending on the performance requirements of Level 4 + STANAG 4569 military standard(projectile 14.5 mm × 114 mm API B32) and especially on a design philosophy which is analysed with the specifications. The backplate of this new composite is a hybrid material of metal matrix Composite(mmC) reinforced with carbon nanotubes(CNTs), manufactured with the use of powder metallurgy technique. The composite backplate material was morphologically, mechanically and chemically analysed. Results show that all plates are presenting high mechanical properties and ballistic characteristics, compared to commonly used armour plates. Real military ballistic tests according to AEP-STANAG 4569 were carried out for the total composite armour systems. After the ballistic tests, AA2024-CNT3 showed the best protection results, compared with the other plates(AA2024-CNT1 and AA2024-CNT2), with the projectile being unable to fully penetrate the composite plate.

关键词： Passive armour protection Protective armour Ballistic performance Hybrid composites Vehicle protection

Degradation of methylene Blue and Rhodamine B Using a New Visible Light-Responsive Photocatalyst, KSb_2PO_(8-x)N_y

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Acta metallurgica Sinica(English Letters) 2016年第4期29卷 335-343页

作者： G.Ravi ch.Sudhakar Reddy K.Sreenu Ravinder Guje Radha Velchuri m.Vithal Department of chemistry University College of ScienceOsmania University

Potassium phosphatoantimonates, KSb2PO8 （KSbPO） and KSb2PO8-xNy （KSbPON）, are prepared by solidstate method. Urea is employed as a source of nitrogen for N-doping. Structural, morphological and optical properties of both KSbPO and KSbPON are characterized by powder X-ray diffraction （PXRD）, scanning electron microscopy, energydispersive spectroscopy, Fourier transform infrared spectroscopy and UV-visible diffuse reflectance spectroscopy. Both samples are found to crystallize in a monoclinic lattice with Cc space group. The d-lines of KSbPO and KSbPON are refined by least square fitting the PXRD data, using POWD software to obtain their unit cell parameters. The bandgap energy （Eg） of both pristine and N-doped KSbPO is found from their Kubelka-munk plot. The KSbPON/visible photocatalytic degradation of methylene blue and rhodamine B has been investigated in aqueous heterogeneous suspension. The generation of .OH in the presence of KSbPON during the photoreaction is verified by a fluorescence technique using terephthalic acid （TA） as a probe.

关键词： Potassium phosphatoantimonates characterization Organic dyes Photodegradation

characterization of the High-Strength mg–3Nd–0.5Zn Alloy Prepared by Thermomechanical Processing

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Acta metallurgica Sinica(English Letters) 2019年第3期32卷 321-331页

作者： Ji■í Kub■sek Drahomír Dvorsk■ Jozef Vesel■ Peter min■rik m■ria Zemkov■ Dalibor Vojtěch Department of metals and Corrosion Engineering Faculty of Chemical Technology University of Chemistry and Technology Prague Department of Physics of materials Charles University

magnesium alloys based on Nd and Zn are promising materials for both aviation industry and medical *** mechanical properties of these materials can be achieved by thermomechanical processing such as extrusion or rolling and by aging treatment, which can significantly strengthen the alloy. The question remains especially about the connection of texture strength created in the alloys based on the specific conditions of preparation. This work focuses on the mg–3 Nd–0.5 Zn magnesium alloy prepared by hot extrusion of the as-cast state at two different temperatures combined with heat pre-treatment. Extrusion ratio of 16 and rate of 0.2 mm/s at 350 and 400 °C were selected for material preparation. The structures of prepared materials were studied by scanning electron microscopy and transmission electron microscopy. The effect of microstructure on mechanical properties was evaluated. Obtained results revealed the strong effect of thermal pre-treatment on final microstructure and mechanical properties of extruded materials. The Hall–Petch relation between grain size and tensile yield strength has been suggested in this paper based on the literature review and presented data. The observed behavior strongly supports the fact that the Hall–Petch of extruded mg–3Nd–0.5 Zn alloys with different texture intensities cannot be clearly estimated and predicted. In addition, Hall–Petch relations presented in literature can be sufficiently obtained only for fraction of the mg–3Nd–0.5 Zn alloys.

关键词： mg–Nd–Zn alloys Extrusion Thermal treatment microstructure mechanical properties