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The mechanisms of color production in black skin versus red skin on the heads of New World vultures

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Avian Research 2023年第1期14卷 86-92页

作者： Nicholas m.Justyn matthew J.Powers Geoffrey E.Hill Kayla Alexander Adrián Naveda-Rodríguez Scott A.Rush Department of Biological Sciences Auburn UniversityAuburnALUSA College of Veterinary medicine Mississippi State UniversityMississippiStateMSUSA Department of Wildlife Fisheriesand AquacultureMississippi State UniversityMississippi StateMSUSA

A determination of how the color of animal integument is produced is a starting point for investigations into the function and evolution of *** mechanisms that give rise to the color of bare skin of New World vultures are largely ***,we investigate the source of color production in the bare skin of Turkey Vultures(Cathartes aura)and Black Vultures(Coragyps atratus).Using UV-vis reflectance spectroscopy,we found evidence that hemoglobin is the primary pigment responsible for the red coloration of the bare skin on the heads of Turkey Vultures,and that eumelanin is responsible for the black coloration of the bare skin on the heads of Black *** microscopy of incisional skin samples further supported these mechanisms of color production by revealing the presence of numerous blood vessels near the surface of the Turkey Vulture skin,and a high concentration of melanosomes in the skin of Black *** high performance liquid chromatography(HPLC),we detected carotenoids within the skin of both species with significantly higher total concentrations of carotenoids in the skin of Turkey Vultures compared to the skin of Black *** carotenoids detected were dietary carotenoids that typically produce yellow coloration when accumulated in integument and were present in low *** hypothesize that the dietary carotenoids present do not contribute to the color of the skin,but rather help to compensate for the lack of melanosomes found in Turkey Vulture *** presence of additional carotenoids may act as an antioxidant to minimize UV damage when the bare Turkey Vulture head skin is exposed to direct sunlight for prolonged periods of time when soaring and scavenging for food.

关键词： Carotenoids Cathartes aura Coragyps atratus Hemoglobin High performance liquid chromatography melanosomes Skin biopsies

Vertex angles effects in the energy absorption of axially crushed kenaf fibre-epoxy reinforced elliptical composite cones

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Defence Technology（防务技术） 2018年第4期14卷 327-335页

作者： mohamed Alkateb S.m.Sapuan Z.Leman m.R.Ishak mohammad Jawaid Department of mechanical and manufacturing Engineering Universiti Putra Malaysia Laboratory of Bio Composite Technology Institute of Tropical Forestry and Research Products (INTROP)Universiti Putra Malaysia Aerospace manufacturing Research Centre (AmRC) Universiti Putra Malaysia Departments of Aerospace Engineering Universiti Putra Malaysia

Experimental quasi-static crushing tests were conducted by using a universal testing machine format kenaf-epoxy composite elliptical cones. The work focused on the vertex angle's effects on energy absorption capability; the vertex angles vary from 0° to 24° in 6 increments. The failure modes of the kenaf fibre epoxy composite elliptical cones were observed utilising delegate photos taken during the quasistatic crushing test. Load-deformation curves and deformation histories of typical specimens are presented and discussed. moreover, the effects of cone vertex angles on the load carrying capacity and the energy absorption capability are also discussed. The results show that the energy absorption abilities significantly influence the ellipticity vertex angle as the load carrying capacity. We concluded that the quasi-static axial crushing behaviour of elliptical mat laminated composite cones is strongly affected by their structural geometry and the specific energy absorbed by the composite elliptical cones with vertex angles of 6°, 12°, 18°, and 24°, which is more than an elliptical cone with the vertex angle of 0°(the elliptical tube) at any given deformation. However, the specific energy absorption for the elliptical composite cone showed a positive correlation, i.e., the more the angle increased, the more energy was absorbed. In this regard, an elliptical composite cone with a 24° angle exhibited the best energy absorption capability.

关键词： Kenaf fibres Composite materials Elliptical cone Vertex angle Collapsible Energy absorption

Electrical and dielectric properties of Ni_(0.5)Co_(0.5)Ga_(x)Fe_(1.8-x)O_(4)(x≤1.0)spinel ferrite microspheres

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Journal of Rare Earths 2023年第2期41卷 259-267页

作者： S.Akhtar m.A.Almessiere B.Unal A.Demir Korkmaz Y.Slimani N.Tashkandi A.Baykal A.Ul-Hamid A.manikandan Department of Biophysics Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Department of Physics College of ScienceImam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Institute of Forensic Sciences and Legal medicine Istanbul University-CerrahpasaBuyukcekmece CampusBuyukcekmece-Istanbul34500Turkey Department of Chemistry Istanbul Medeniyet UniversityUskudar/Istanbul34700Turkey Department of Nanomedicine Research Institute for Research and Medical Consultations(IRMC)Imam Abdulrahman Bin Faisal UniversityP.O.Box 1982Dammam31441Saudi Arabia Core Research Facilities King Fahd University of Petroleum&MineralsDhahran13261Saudi Arabia Department of Chemistry Bharath Institute of Higher Education and Research(BIHER)Bharath UniversityChennaiTamil Nadu600073India Center for Catalysis and Renewable Energy Bharath Institute of Higher Education and Research(BIHER)ChennaiTamil Nadu600073India

microspheres of Ni_(0.5)Co_(0.5)Ga_(x)Fe_(2-x)O_(4)(x≤1.0)microsphere spinel ferrites(NiCoGaFe-mSFs)and carbon spheres were prepared via a hydrothermal *** micro structure of microspheres was investigated through scanning and transmission electron microscopy(SEm and TEm),respectively,and X-ray diffraction(XRD).The electrical and dielectric properties of NiCoGaFe-mSF at temperatures ranging from20 to 120℃(between 293,1×10^(3)and 393.1×10^(3))for f≤3.0 mHz were systematically studied as a result of 3D graphical drawing of the data obtained from an impedance *** parameters such as ac/dc conductivity,dielectric loss,dielectric constant,activation energy,dissipation factor and Cole-Cole impedance spectra were extensively evaluated for various Ga ion mole ratios in the substitution where x≤*** notice that the ac conductivity mostly obeys exponential power law rules,which vary significantly with the substitution ratios of Ga *** analyses confirm that differences in conduction mechanisms in NiCoGaFe-mSFs are mainly due to grain-to-grain boundaries related to Ga ion substitution *** change in dielectric constant of NiCoGaFe-mSFs is strongly dependent on the substitution rates and results in a normal dielectric distribution with *** tangential loss for all micro spheres is observed to vary with measured temperatures and their frequency dependencies can be attributed to the conduction mechanism similar to Koop’s phenomenological *** is clearly seen that the formation of semicircles is dominated by all the NiCoGaFe-mSFs and the diameter of the semicircles mostly decreases with increasing temperature,as evidence of a temperaturedependent relaxation mechanism.

关键词： Spinel ferrites microspheres Electrical properties Ac/dc conductivity Dielectric properties Rare earths

High-performance polymer electrolyte membranes incorporated with 2D silica nanosheets in high-temperature proton exchange membrane fuel cells

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Journal of Energy Chemistry 2022年第1期31卷 323-334,I0009页

作者： Zunmin Guo Jianuo Chen Jae Jong Byun Rongsheng Cai maria Perez-Page madhumita Sahoo Zhaoqi Ji Sarah J.Haigh Stuart m.Holmes Department of Chemical Engineering and Analytical Science The University of ManchesterM139PLUnited Kingdom Department of materials The University of ManchesterM139PLUnited Kingdom

Silica nanosheets(SN)derived from natural vermiculite(Verm)were successfully incorporated into polyethersulfone-polyvinylpyrrolidone(PES-PVP)polymer to fabricate high-temperature proton exchange membranes(HT-PEms).The content of SN filler was varied(0.1-0.75 wt%)to study its influence on proton conductivity,power density and *** from the hydroxyl groups of SN that enable the formation of additional proton-transferring pathways,the inorganic-organic membrane displayed enhanced proton conductivity of 48.2 mS/cm and power density of 495 mW/cm^(2) at 150℃ without humidification when the content of SN is 0.25 wt%.Furthermore,exfoliated SN(E-SN)and sulfonated SN(S-SN),which were fabricated by a liquid-phase exfoliation method and silane condensation,respectively,were embedded in PES-PVP polymer matrix by a simple blending *** to the significant contribution from sulfonic groups in S-SN,the membrane with 0.25 wt%S-SN reached the highest proton conductivity of51.5 mS/cm and peak power density of 546 mW/cm^(2) at150℃,48%higher than the pristine PES-PVP *** to unaltered PES-PVP membrane,SN added hybrid composite membrane demonstrated excellent durability for the fuel cell at 150℃.Using a facile method to prepare 2D SN from natural clay minerals,the strategy of exfoliation and functionalization of SN can be potentially used in the production of HT-PEms.

关键词： Silica nanosheets Vermiculite High-temperature proton exchange membrane Proton conductivity

Soil bentonite wall protects foundation from thrust faulting: analyses and experiment

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Earthquake Engineering and Engineering Vibration 2013年第3期12卷 473-486页

作者： meysam Fadaee I. Anastasopoulos G. Gazetas m.K. Jafari m. Kamalian International Institute of Earthquake Engineering and Seismology School of Civil Engineering National Technical University

When seismic thrust faults emerge on the ground surface, they are particularly damaging to buildings, bridges and lifelines that lie on the rupture path. To protect a structure founded on a rigid raft, a thick diaphragm-type soil bentonite wall （SBW） is installed in front of and near the foundation, at sufficient depth to intercept the propagating fault rupture. Extensive numerical analyses, verified against reduced-scale （1 g） split box physical model tests, reveal that such a wall, thanks to its high deformability and low shear resistance, ＂absorbs＂ the compressive thrust of the fault and forces the rupture to deviate upwards along its length. As a consequence, the foundation is left essentially intact. The effectiveness of SBW is demonstrated to depend on the exact location of the emerging fault and the magnitude of the fault offset. When the latter is large, the unprotected foundation experiences intolerable rigid-body rotation even if the foundation structural distress is not substantial.

关键词： soil bentonite wall fault rupture soil-structure interaction seismic hazard mitigation tectonic deformation soil-foundation interaction

Revealing pion and kaon structure via generalised parton distributions

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Chinese Physics C 2022年第1期46卷 80-101页

作者： K.Raya Z-F.Cui L.Chang J.m.morgado C.D.Roberts J.Rodríguez-Quintero School of Physics Nankai UniversityTianjin 300071China Departamento de Física Teórica y del Cosmos Universidad de GranadaE-18071GranadaSpain Instituto de Ciencias Nucleares Universidad Nacional Autónoma de MéxicoApartado Postal 70-543CDMX 04510México School of Physics Nanjing UniversityNanjingJiangsu 210093China Institute for Nonperturbative Physics Nanjing UniversityNanjingJiangsu 210093China Department of Integrated Sciences and Center for Advanced Studies in Physics Mathematics and ComputationUniversity of HuelvaE-21071 HuelvaSpain

Clear windows onto emergent hadron mass(EHm)and modulations thereof by Higgs boson interactions are provided by observable measures of pion and kaon structure,many of which are accessible via generalised parton distributions(GPDs).Beginning with algebraic GPD Ansätze,constrained entirely by hadron-scaleπand K valence-parton distribution functions(DFs),in whose forms both EHm and Higgs boson influences are manifest,numerous illustrations are *** include the properties of electromagnetic form factors,impact parameter space GPDs,gravitational form factors and associated pressure profiles,and the character and consequences of allorders *** analyses predict that mass-squared gravitational form factors are stiffer than electromagnetic form factors;reveal that K pressure profiles are tighter than profiles,with both mesons sustaining near-core pressures at magnitudes similar to that expected at the core of neutron stars;deliver parameter-free predictions for and K valence,glue,and sea GPDs at the resolving scale l=2GeV;and predict that at this scale the fraction of meson mass-squared carried by glue and sea combined matches that lodged with the valence degrees-of-freedom,with a similar statement holding for mass-squared radii.

关键词： continuum Schwinger function methods emergence of hadron mass Nambu-Goldstone modes-pions and kaons nonperturbative quantum field theory parton distributions strong interactions

Effect of the addition of rare earths on the activity of alumina supported copper cobaltite in CO oxidation, CH_4 oxidationand NO decomposition

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Journal of Rare Earths 2015年第4期33卷 382-390页

作者： B.Ivanov I.Spassova m.milanova G.Tyuliev m.Khristova Institute of General and Inorganic Chemistry Bulgarian Academy of Sciences Faculty of Chemistry and Pharmacy Sofia University Institute of Catalysis Bulgarian Academy of Sciences

The effect of the addition of small amounts of rare earths （Ln=La, Ce, Nd and Gd） to alumina supported copper-cobalt spinel oxide on the catalysts efficiency in CO and CH4 oxidation and in NO decomposition was investigated. Samples of Ln/CuCo/AI catalyst were prepared and characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, atomic absorption spectroscopy （AAS）, scanning electron mieroscopy-energy dispersive spectroscopy （SEm-EDS）, H2-temperature-programmed reduc- tion （H2-TPR）, electron paramagnetic resonanee （EPR） spectroscopy and low temperature nitrogen adsorption, The results showed that the addition of rare earths changed the surface state of the alumina supported copper-cobalt spinel catalyst. As a result, partial re- duction of copper species was observed as well as migration of these species between the surface and the bulk. The Ln/CuCo/A1 catalysts behaved differently in oxidation and reduction processes. In oxidation processes where oxide structure was important, Ce/CuCo/A1 and Nd/CuCo/A1 were the most active catalysts. The catalyst Ce/CuCo/AI was the most active in the oxidation reactions because of the availability and favorable surface distribution of the redox couples Cu＋/Cu2＋ and Ce3＋/Ce4＋. In NO decompostion, Ln-modified catalysts significantly improved the selectivity of the process to N2.

关键词： copper cobaltite NO decomposition CO oxidation CH4 oxidation rare earths

Evolution of zinc morphology during continuous electrodeposition

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Journal of University of Science and Technology Beijing 2003年第1期10卷 35-38页

作者： Ailing Fan m.Kurosaki 等 DepartmentofmaterialsPhysicsandChemistry UniversityofScienceandTechnologyBeijingBeijing100083China SteelResearchLaboratoires NipponSteelCorporation20-1ShintomiFuttsuChiba-ken293

The morphology evolution of zinc continuous electrodeposits with nano-sized crystals on the ferrite substrate has been studied by in-situ scanning tunnel spectroscopy (STm). It is found that the morphology of zinc electrodeposits varies from initial granules with a size of about 30nm to layered platelets with increasing deposition time. meanwhile, the crystal structure of the zinc electrodeposits is identified to be hexagonal η-phase by X-ray diffraction. The orientation relationship between zinc crystals and the substrate surface can be interpreted in terms of the misfit and the atomic correspondence of the interphase boundary between the η-phase deposits and α-Fe substrate.

关键词： Zn electrodeposit crystal morphology epitaxial growth orientation relationship scanning tunnel spectroscopy

Unpaved road erosion after heavy storms in mountain areas of northern China

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International Soil and Water Conservation Research 2022年第1期10卷 29-37页

作者： Chunmei Wang Baoyuan Liu Qinke Yang Guowei Pang Yongqing Long Lei Wang Richard m.Cruse Weiqin Dang Xin Liu Enheng Wang Shaanxi Key Laboratory of Earth Surface System and Environmental Carrying Capacity College of Urban and Environmental SciencesNorthwest UniversityXi'an710127PR China Key Laboratory of National Forestry and Grassland Administration on Ecological Hydrology and Disaster Prevention in Arid Regions Xi'an710048PR China Advanced Institute of Natural Sciences Beijing Normal University at ZhuhaiZhuhai519087PR China State Key Laboratory of Earth Surface Processes and Resource Ecology School of GeographyBeijing Normal UniversityBeijing100875PR China Department of Agronomy Iowa State UniversityAmesIA50011USA Suide Experimental Station for Soil and Water Conservation the Yellow River Conservancy CommissionYulinShaanxi719000PR China Key Laboratory of Sustainable Forest Ecosystem management-ministry of Education Northeast Forestry UniversityHarbinHeilongjiang150040PR China

more frequent extreme rainfall events associated with global climate change cause greater challenges for soil *** erosion occurs on many unpaved roads since these structures create important water flow paths during heavy *** present research aimed to investigate the intensity and influencing factors of unpaved road erosion under varied land use and management conditions(sloping cropland,terraced cropland,forest&grass).The erosion occurred in the watersheds contributing runoff water to roads after the greatest rainfall event recorded in the mountain area of northern China caused by Typhon *** research was conducted in an agricultural-forest-dominated watershed based on field investigation and UAV-based image analysis.A road erosion level classification standard was given according to the occurrence of rills,ephemeral gullies,and *** erosion happened on 67% of the unpaved roads;42% of them suffered moderate to severe erosion in which ephemeral gullies or gullies *** average erosion amount from these roads was 2280.75 t ha-1 and was significantly influenced by the watershed land use type and *** dominant factor governing unpaved road erosion associated with terraced cropland was vegetation coverage on *** area was the most important factor for road erosion in sloping cropland and forest&grass land,and road gradient was also a critical ***,and forest&grass in drainage areas significantly reduced unpaved road erosion by 85%and,47%,respectively,compared to sloping *** integrated measures should be used to prevent unpaved road *** results of this research can be applied to road protection against erosion in heavy storms.

关键词： Unpaved road erosion Heavy storm Gully Land management Climate change