检索结果-南通市图书馆

Structural effects induced by dialysis-based purification of carbon nanomaterials

在线全文

学校读者我要写书评

暂无评论

Nano Materials Science 2024年第4期6卷 475-483页

作者： A.D.Veloso A.M.Ferraria A.M.Botelho do Rego A.S.Viana A.J.S.Fernandes A.J.Fielding R.A.Videira M.c.Oliveira cQ-VR and chemistry Department University of Trás-os-Montes e Alto Douro BSIRG iBB-Institute for Bioengineering and BiosciencesDepartment of Chemical Engineeringand Associate Laboratory i4HB-Institute for Health and BioeconomyInstituto Superior TécnicoUniversidade de Lisboa centro de Química Estrutural Institute of Molecular SciencesDepartamento de Química e BioquímicaFaculdade de CiênciasUniversidade de Lisboa I3N and Physics Department University of AveiroCampus de Santiago Faculty of Science Pharmacy and Biomolecular SchoolLiverpool John Moores University REQUIMtE/LAQV Laborat orio de FarmacognosiaDepartamento de QuímicaFaculdade de Farm aciaUniversidade do Porto

Dialysis plays a crucial role in the purification of nanomaterials but its impact on the structural properties of carbon nanomaterials was never ***,a carbon-based nanomaterial generated electrochemically in potassium phosphate buffer,was characterized before and after dialysis against pure *** is shown that dialysis affects the size of the carbon domains,structural organization,surface functionalization,oxidation degree of carbon,and grade of ***,dialysis drives the nanomaterial organization from discrete roundish carbon domains,with sizes ranging from 70 to 160 nm,towards linear stacking structures of small nanoparticles （cohol and ether （epoxide） surface groups evolve into more oxidized carbon groups （e.g.,ketone and ester groups）.Investigation of the as-prepared nanomaterial by electron paramagnetic resonance （EPR） revealed a resonance signal consistent with carbon-oxygen centred ***,this study brings to light the selective affinity of the carbon nanomaterial under study to capture Na+ions,a property greatly enhanced by the dialysis process,and its high ability to trap oxygen,particularly before *** findings open new perspectives for the application of carbon-based nanomaterials and raise awareness of the importance of structural changes that can occur during the purification of carbon-based nanomaterials.

关键词： Nanocarbon Surface functionalization NMR XPS Hydrophilic carbon Paramagnetic

共享社会经济路径(SSP1~5)中国及分省人口预估数据集_v2

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

气候变化研究进展 2024年第4期20卷 492-497页

作者：郭欢欢景丞姜彤苏布达王艳君杨聿铭南京信息工程大学地理科学学院/灾害风险管理研究院南京210044 南京信息工程大学气候与环境治理研究院南京210044 中国科学院新疆生态与地理研究所荒漠与绿洲生态国家重点实验室乌鲁木齐830011 江苏第二师范学院地理科学学院南京210013

政府间气候变化专门委员会(IPcc)第六次评估报告综合报告《气候变化2023》明确指出自工业化以来,人类活动带来的温室气体排放导致全球变暖,使全球极端天气气候事件日益增多,对自然和人类的发展带来巨大挑战[1]。为反映未来社会经济面临... 详细信息

政府间气候变化专门委员会(IPcc)第六次评估报告综合报告《气候变化2023》明确指出自工业化以来,人类活动带来的温室气体排放导致全球变暖,使全球极端天气气候事件日益增多,对自然和人类的发展带来巨大挑战[1]。为反映未来社会经济面临的气候变化适应和减缓挑战,IPcc提出5种共享社会经济路径,包括可持续发展路径(SSP1)、中间路径(SSP2)、区域竞争路径(SSP3)、不均衡路径(SSP4),以及以传统化石燃料为主的路径(SSP5)。开展SSP1~5路径下人口的变化预估,是气候变化影响研究和气候政策制定的核心。

关键词：气候变化适应极端天气气候事件气候变化影响经济路径全球变暖化石燃料人口预估 SSP

Fruit Powder of tetrapleura tetraptera in Local Feed on Some Zootechnical Performances of Juveniles of clarias gariepinus in concrete tank

在线全文

学校读者我要写书评

暂无评论

Open Journal of Animal Sciences 2024年第2期14卷 56-69页

作者： Ngouana tadjong Ruben Abdoulaye Abdoulaye Kana Jean Raphaël téguia Alexis Laboratory of Aquaculture and Demography of Fisheries Resources Aquaculture Department Institute of Fisheries and Aquatic Science of Yabassi University of Douala Douala Cameroon Laboratory of Animal Nutrition Department of Animal Science Faculty of Agronomy and Agricultural Sciences University of Dschang Dschang Cameroon

this study focused on the supplementation of four-sided spice fruit powder (tetrapleura tetraptera) on some zootechnical performances of juveniles of clarias gariepinus and was carried out from February 14 to July 20 at the Massoma Fish Farm of Bojongo Mbeidi located in the Littoral Region, Department of Wouri, Douala IV district. the farm benefits from a climate favorable to aquaculture activity. For this purpose, five (5) treatments were tested including t0+ (imported feed), t0-, t0.3, t0.4, and t0.5 respectively for the treatments with 0% supplemented food;0.3%;0.4% and 0.5% of tetrapleura tetraptera powder. A total of 450 clarias gariepinus fry with an initial average weight of 7 ± 1.5 g, were distributed in happas of 0.49 m2 each placed in triplicate in a completely randomized device. Four isoprotein foods with 38% crude protein were formulated to feed these fry at 7% of their biomass per day for 15 days then to their fullness until the end of the experiment. Intermediate fishing was carried out every fortnight. 75 days later, the results recorded show that the highest average survival rate (96.44% ± 3.5%) was recorded with the subjects fed feed supplemented with 0.4% t. tetraptera powder. the average weight (120.93 ± 67.20), weight gain (113.93 ± 67.20), specific growth rate (3.64 ± 0.79% g/d) and total lengths and standard (26.43 ± 1.9 and 23.66 ± 1.76) the highest were recorded with the t0+ treatment (imported feed). the highest conditioning factor K (2.14 ± 0.15) was recorded with the treatment supplemented with 0.4% t. tetraptera. the lowest conversion ratio (1.28) was recorded with the treatment fed with imported blue crown food (t0+). Furthermore, the lowest production cost was recorded with the treatment supplemented with 0.4% t. tetraptera. It appears from this study that the juveniles of c. gariepinus better value the feed substituted with 0.4% of the powder of fou

关键词： tetrapleura tetraptera Local Feed Zootechnical Performance Juvenile of clarias gariepinus

Improvising the Self-Healing capabilities of concrete Using Different Pozzolanic Materials and crystalline Admixtures

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of technology(Materials Science) 2022年第3期37卷 429-439页

作者： A Ravitheja t chandra Sekhara Reddy c Sashidhar SVR Engineering college AyyalurNandyalKurnoolAndhra PradeshIndia civil Engineering G Pulla Reddy Engineering CollegeKurnoolAPIndia Jawaharlal Nehru technological University AnantapurIndia

to analyse the self-healing capacities in terms of mechanical performance of the pozzolanic materials,such as,fly ash,metakaolin and silica fume and crystalline ***-cracked concrete cubes with about 0.05 mm width were exposed to four different environmental conditions at different exposure times in order to determine the effect of temperature and water availability on the self-healing *** the exposure,the control and tested concrete cubes were evaluated for regained strength,void reduction,corrosion inhibition,damp proofing,relative impermeability and *** samples with SF10cA have better cementitious filling and low percentage of voids and water absorption.

关键词： crystalline admixtures pozzolanic materials self-healing

Process development for the direct solvent extraction of nickel and cobalt from nitrate solution:aluminum,cobalt,and nickel separation using cyanex 272

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2017年第1期24卷 37-46页

作者： Zela t.Ichlas Don c.lbana Leaching and Separation technologies Group Department of Mining Engineering and Metallurgical EngineeringWA School of MinesCurtin UniversityKalgoorlieWA 6430Australia

A direct solvent extraction（DSX） process for purifying nickel and cobalt from the nitric acid leach solution of nickel laterite ores was conceived and experimentally probed. the proposed process consists of two solvent extraction（SX） steps but with only one extractant - bis（2,4,4-trimethylpentyl）phosphinic acid（cyanex？ 272） - used in both steps. the first extraction step involved the removal of aluminum and zinc, whereas the second extraction step involved the separation of cobalt along with manganese from nickel. the experimental results showed essentially quantitative removal of aluminum（〉97%） and zinc（〉99%） in a single extraction stage using 20vol% cyanex 272 at pH 2.1. Some cobalt（32%） and manganese（55%） were co-extracted but were easily scrubbed out completely from the loaded organic phase using dilute sulfuric acid at pH ≤ 1.38. cobalt and manganese in the first extraction raffinate were extracted completely in four extraction stages at staggered pH values of 4.0, 4.4, 4.5, and 4.0 in the first, second, third, and fourth stages, respectively, using also 20vol% cyanex 272. A small amount of nickel（up to 6.6%） was co-extracted but was easily scrubbed out completely with dilute sulfuric acid at pH 2.0. A flow diagram showing the input and output conditions and the metals separated under the deduced optimum conditions is presented.

关键词： solvent extraction aluminum cobalt nickel nickel laterite ores

Impact of device resistances in the performance of graphene‑based terahertz photodetectors

在线全文

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2024年第2期17卷 87-97页

作者： O.castelló Sofía M.López Baptista K.Watanabe t.taniguchi E.Diez J.E.Velázquez-Pérez Y.M.Meziani J.M.caridad J.A.Delgado-Notario Department of Applied Physics University of Salamanca37008 SalamancaSpain Unidad de Excelencia en Luz y Materia Estructurada(LUMES) University of Salamanca37008 SalamancaSpain Research center for Electronic and Optical Materials National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Research center for Materials Nanoarchitectonics National Institute for Materials Science1-1 NamikiTsukuba 305-0044Japan Nanotechnology Group USAL-NanolabUniversity of Salamanca37008 SalamancaSpain

In recent years,graphene field-effect-transistors(GFEts)have demonstrated an outstanding potential for terahertz(tHz)photodetection due to their fast response and *** features are essential to enable emerging tHz applications,including 6G wireless communications,quantum information,bioimaging and ***,the overall performance of these photodetectors may be utterly compromised by the impact of internal resistances presented in the device,so-called access or parasitic *** this work,we provide a detailed study of the influence of internal device resistances in the photoresponse of high-mobility dual-gate GFEt *** dual-gate architectures allow us to fine tune(decrease)the internal resistance of the device by an order of magnitude and consequently demonstrate an improved responsivity and noise-equivalent-power values of the photodetector,*** results can be well understood by a series resistance model,as shown by the excellent agreement found between the experimental data and theoretical *** findings are therefore relevant to understand and improve the overall performance of existing high-mobility graphene photodetectors.

关键词： Graphene tHz Photodetector Field-effect transistor Plasmonic

Bounds on the clique-transversal number of regular graphs

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science china Mathematics 2008年第5期51卷 851-863页

作者： cHENG t.c.E Department of Logistics the Hong Kong Polytechnic University

A clique-transversal set D of a graph G is a set of vertices of G such that D meets all cliques of G. the clique-transversal number, denoted τ c (G), is the minimum cardinality of a clique-transversal set in G. In this paper we present the bounds on the clique-transversal number for regular graphs and characterize the extremal graphs achieving the lower bound. Also, we give the sharp bounds on the clique-transversal number for claw-free cubic graphs and we characterize the extremal graphs achieving the lower bound.

关键词： graph regular graph claw-free cubic graph clique-transversal set clique-transversal number 05c65 05c69 05c75

Rhyacian and Neoproterozoic magmatic associations of the Gurupi Belt,Brazil: Implications for the tectonic evolution, and regional correlations

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2020年第6期11卷 2243-2269页

作者： Evandro L.Klein Elem c.S.Lopes Joseneusa B.Rodrigues Sulsiene M.souza-Gaia Umberto G.cordani Geological Survey of Brazil-SBN Quadra 02Bloco HEd.Central Brasília1°AndarAsa NorteBrasíliaDFCEP:70040-904Brazil GPGE-Grupo de Pesquisa Em Geologia Econômica PPGG-Programa de Pòs-Graduação Em Geologia e GeoquímicaUniversidade Federal Do ParáBelémPABrazil Geological Survey of Brazil Av.Dr.Freitas3645BelémPACEP:66095-110Brazil Universidade de São Paulo Instituto de GeociênciasRua Do Lago562Cidade UniversitariaSão Paulo-SPCEP:05508-080Brazil

the Gurupi Belt,in north-northeastern Brazil,is a mobile belt developed in the south-southwestern margin of the Sao Luis cratonic fragment and crops out as a tectonic and erosional window within the Phanerozoic ***,petrographic,geochemical,geochronological,and Nd isotopic information(new and published)constrain the timing and types of magmatic associations present in the belt and the tectonic settings in which they *** Rhyacian was the main period of magmatic activity,which can be grouped into two main stages.(1)~2185-2130 Ma:pre-collisional,juvenile,calc-alkaline magnesian and calcic ferroan granitoid suites,and minor calc-alkaline and tholeiitic mafic plutonism(now amphibolites),formed in intra-oceanic to transitional/continental arcs;and intra-or back-arc volcano-sedimentary basin.(2)~2125-2070 Ma:syn-(two-mica granites)to late-collisional(potassic to shoshonitic granites and quartz-syenite)plutonic suites produced after crustal thickening and melting,with localized migmatization,that intruded during the compressive D1 deformational phase and concomitantly with greenschist to amphibolite *** is a zonation of the Rhyacian episodes,with intra-oceanic stages occurring to the northeast,and the continental arc and collisional phases occurring to the southwest,indicating the presence of an active continental margin to the southwest,and subduction from NE to SW(present-day configuration).this magmatic framework is a continuation to the south of what is described for the Sao Luis cratonic fragment to the north,and the orogenic scenario is identical to what is observed for the same period in the West African craton(Eburnean/Birrimian orogen),which additionally supports previous geological *** the Neoproterozoic,a few magmatic occurrences are *** extensional event allowed the intrusion of an anorogenic,nepheline syenite at ca.730 Ma,which was followed by the intrusion of a crustal,calc-alkaline microtonalite,of uncertain

关键词： Neoproterozoic Paleoproterozoic Accretionary orogeny Intracontinental orogeny West Gondwana Isotope geology

Germination strategies of annual and short-lived perennial species in the Arabian Desert

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2020年第6期12卷 1071-1082页

作者： Arvind BHAtt David J GALLAcHER Paulo R M souza-FILHO Lushan Botanical Garden Chinese Academy of SciencesJiujiang 332900China School of Life and Environmental Sciences The University of SydneyNarrabri NSW 2390Australia Multidisciplinary center of Barra Federal University of Western BahiaBarra 47100-000Brazil

Germination timing is highly regulated in short-lived plant species since it strongly influences recruitment success of *** deserts,the spatiotemporal distribution of plant-available water is highly episodic and unpredictable,making winter months more favorable for seed germination when other abiotic conditions *** hypothesized that changes in photoperiod and thermoperiod would impact germination more in seeds that had undergone in situ *** assessed 21 annual and short-lived perennial species in the Arabian Desert to find(1)if seeds were dormant at maturity,(2)if in situ seed storage increased germination percentage compared with no storage,(3)if photoperiod and thermoperiod germination requirements were influenced by in situ storage,and(4)if a phylogenetic association in seed germination could be *** of each species collected in early 2017 were divided into two *** was tested for germination within one week(fresh seeds).the other was stored in situ at the maternal location(stored seeds)until October 2017 and tested for seed germination in the first week of *** germination was conducted in incubators at two thermoperiods(15℃/20℃ and 20℃/30℃;12 h/12 h),and two photoperiods(12 and 0 h light per day).Results indicated that seed germination percentages of 13 species were significantly enhanced by in situ storage.A thermoperiod response was exhibited by stored,but not fresh *** exposure increased germination of fresh seeds but had only a minimal effect on stored *** traits exhibited no phylogenetic *** result indicated that selection pressure for germination strategy was stronger than that for taxonomic traits of these desert species.

关键词： desert species dormancy germination light temperature phylogeny