972 resultados para Verrazzano, Girolamo da, fl. 1524-1528.
Resumo:
Multitracer technique was used to study the uptake and distribution of some relatively long half-life radionuclides Be, Na, Mn, Co, Sc to growing cucumber (Cucumis Sativus L.) with two different treatments. In Hoagland solution, only Mn-54 and Co-60 accumulated in the every part of plants. Mn-54, Co-60 and other radionuclides were absorbed in distilled water. The results indicate that there were major differences in the accumulation of trace elements between the two different treatments.
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The long-term variations in the strength of the geomagnetic field provide important constraints on the chemical-physical processes of the Earth’s interior. Especially, the intensity of the geomagnetic field during the Cretaceous normal superchron (CNS) is crucial to understand the geodynamo. But a paucity of paleointensity further limits to obtain essential knowledge interior process in the deep earth. In order to improve the experimental efficiency, this study tried to apply two new rock magnetic methods (FORC diagram and low-temperature demagnetization technique) to determine the paleointensity. First, some problems in the theory and technique in paleointensity experiments were introduced. A combined palaeomagnetic and geochronologic study was further conducted on a basaltic lava sequence at Jianchang in Liaoning Province, northeastern China. Radiometric 40Ar/39Ar dating indicates that the volcanism occurred at about 119 Ma within the marine anomaly C34n in Cretaceous normal superchron (CNS). Rock magnetic investigations show that pseudo-single domain (PSD) titanium-poor titanomagnetite is dominant in the studied lava flows. Both stepwise thermal and alternating field demagnetizations isolate the well-defined normal characteristic remanent magnetization (ChRM) in three independent lava flows with a mean direction of D/I = 6.0/51.9 degree(a95 = 12.3degree). Palaeointensity was determined using the modified Thellier method with systematic partial thermoremanent magnetization (pTRM) checks on total 72 samples, but only 10 samples exhibit ideal linear behavior on the Arai-plot in the temperature interval of 300-560 C and yield an average paleointensity of (25.8+/-1.4)uT. In addition, slopes of the line defined by the initial and the final points on the Arai-plot for the other 18 samples with characteristic PSD features give an average paleointensity estimation value of (24.8+/-1.9)uT. The consistency of these two approaches confidently demonstrates the fidelity of our results. The overall mean field strength determined using both approaches are thus estimated to be (25.2+/-0.7 )uT. This value corresponds to the virtual dipole magnetic moments (VDM) of (4.5+/-0.1)E22 Am^2, which is about half of the value of present field. This finding suggests that palaeointensity just at the onset of the CNS is characterized by a weak magnetic field.
Resumo:
In order to carry out high-precision three-dimensional "integration" for the characteristics of the secondary seismic exploration for Biyang Depression, in the implementation process, through a combination of scientific research and production, summed up high-precision seismic acquisition, processing and interpretation technologies suitable for the eastern part of the old liberated areas, achieved the following results: 1. high-precision complex three-dimensional seismic exploration technology series suitable for shallow depression Biyang block group. To highlight the shallow seismic signal, apply goal-based observing system design, trail from the small panel to receive and protect the shallow treatment of a range of technologies; to explain the use of three-dimensional visualization and coherent combination of full-body three-dimensional fine interpretation identification of the 50-100 m below the unconformity surface and its formation of about 10 meters of the distribution of small faults and improve the small block and stratigraphic unconformity traps recognition. 2. high-precision series of three-dimensional seismic exploration technology suitable for deep depression Biyang low signal to noise ratio of information. Binding model using forward and lighting technology, wide-angle observation system covering the design, multiple suppression and raise the energy of deep seismic reflection processing and interpretation of detailed, comprehensive reservoir description, such as research and technology, identified a number of different types of traps. 3. high-precision seismic exploration technology series for the southern Biyang Depression high steep three-dimensional structure. The use of new technology of seismic wave scattering theory and high-precision velocity model based on pre-stack time migration and depth migration imaging of seismic data and other high-precision processing technology, in order to identify the southern steep slope of the local structure prediction and analysis of sandstone bedrock surface patterns provide a wealth of information.
Resumo:
Sulige gas field is located in Northwest of Yi-Shan Slope of the Ordos Basin. The Shan 1 Member of the Shanxi Formation and He8 Member of the ShiHeZi Formation are not only objective strata of research but also main producing strata of the Sulige Field. From core and wireline log data of 32 wells in well Su6 area of Sulige field, no less than six lithofaice types can be recognised. They are Gm,Sl,Sh,Sm,Sp,Fl,Fm. Box-shaped, bell-shaped, funnel-shaped and line-segment-shaped log are typcial gamma-ray log characters and shapes. The Depositonal system of the Shan1-He8 strata in research area have five bounding-surface hierarchies and was composed of six architectural elements, CH, LS,FF(CH),SB,LA,GB. The depositional model of Shan 1 was the type of a sandy meandering river with natural levee, abandoned channels and crevasse splay. Channel depth of this model maybe 7-12 m and the fullest-bank flow can reach 14 m high. Based on analysis of depositional causes, a sandy braided river model for the depositional system of He 8 can be erected. It consists of active main channels, active chute channels, sheet-like sand bars, abandoned main channels and abandoned chute channels. Channel depth of this model can be 3-4 m with 9 m of highest flow. Six gamma-ray log cross sections show that the connectivity of sandbodies through Shan 1 Member is lower than He 8. Influenced by occurrence of mudy and silty deposits, vertical connectivity of sandbodies through He 8 is not high.
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The Baoyintu Group, lies in Wulate-zhongqi, Inner Mongolia, is a set of medium-grade metamorphic rock series which undergoes complex deformations. It consists of pelite schist, greenschist, plagioclase amphibolite quartzite and marble. The pelite schist is the main rock type and contains the classic medium pressure metamorphic minerals. The author divided Baoyintu group into five assemblages, investigated the rock association and plotted geological section of each assemblage in this area. Based on the systemically study of structural geology, petrology, geochemistry and mineralogy, the author reconstructs the protolith, sedimentary environment and tectonic evolution, discusses the mesoscopic and microscopic structure, metamorphism, geochemistry characters and the correlation between porphyroblast growth and deformation-metamorphism. There are three phase deformations in the research area: the earliest one occurred as the Baoyintu group deformed and metamorphosed and the main structure pattern is tight fold within layers during the Dl, large scale reversed fold and two phase faults (Fl fault and F2 fault) during the D2, and superimposed fold and F3 fault during D3. The F3 trancate the Wenduermian group of Silurian. The second and third phase deformation are relate to the orogenic event of late period of early Paleozoic. According to the rock association ,characteristics of the rocks and research of geochemistry, we get some information of the sedimentary environment and tectonic evolution of Baoyintu group. The source rocks are a set of terrigenous deposits-volcanic formation which reflect the history of the tectonic setting: stable- active-restable. And there are two sedimentary cycle from first assemblage to fifth assemblage: from first assemblage to fourth assemblage is a course of progression and the fifth assemblage is a start of regression. We also get the information of the P-T-t path by studying petrographies and calculating temperature and pressure. The path is not similiat to any classic type. And the interpretation is different from the traditional opinion. The P-T-t path reflects the dynamic course of convergence and uplift, magma underplating, back-arc extension and convergence of continental margin. Applying the theory of deformation partitioning to this area, the author discuss the relationship between deformation and porphyroblast growth, and get the conclusion of the sequence of deformation and metamorphism. At the first time we measure the distribution of chemical composition within the porphyroblast by XRF, confirm the theory of deformation partitioning quantitative and get new understanding about growth phase of porphyroblast and growth mode of porphyroblast: porphyroblast grow in the manner as "rose flower", the growth is controlled by the deformation. The elements distribution in porphyroblast reflects the growth manner and indicate history of metamorphism and deformation. So, we can deduce the metmorphism and deformation from the elements distribution in porphyroblast.
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This thesis presents the design, construction, control and evaluation of a novel force controlled actuator. Traditional force controlled actuators are designed from the premise that "Stiffer is better''. This approach gives a high bandwidth system, prone to problems of contact instability, noise, and low power density. The actuator presented in this thesis is designed from the premise that "Stiffness isn't everything". The actuator, which incorporates a series elastic element, trades off achievable bandwidth for gains in stable, low noise force control, and protection against shock loads. This thesis reviews related work in robot force control, presents theoretical descriptions of the control and expected performance from a series elastic actuator, and describes the design of a test actuator constructed to gather performance data. Finally the performance of the system is evaluated by comparing the performance data to theoretical predictions.
Resumo:
Finalidade; Acervo documental; Organizacao do acervo; Acervo geral; Acervo de periodicos; Acervo de separatas - sp; Acervo de folhetos - fl; Acervo de teses - ts; Acervo de referencia - rf; Como consultar o acervo bibliografico; Servicos prestados; Comutacao bibliografica; Emprestimo de documentos; Orientacao ao usuario; Servico de fotocopia; Normalizacao de referencias e citacao bibliografica; Regulamento geral da biblioteca da Embrapa Soja; Servico de emprestimo; Consideracoes gerais; Obrigacoes do usuario; Inscricao; Periodicidade do emprestimo; Penalidades; Atraso na devolucao de documentos; Perda ou dano de documentos; Documento extraviado; Documento danificado; Comutacao bibliografica; Biblioteca virtual da Embrapa Soja.
Resumo:
Reactions of selenium with imines ((RRC)-C-1=NR2) of aldehydes and ketones in the presence of carbon monoxide, water and triethylamine lead to reductive selenation, on aerobic work-up, to afford symmetrical diselenides ((RRCHSe)-C-1)(2) in good to excellent yields. The proposed mechanism suggests that both in situ generated carbonyl selenide (SeCO) and hydrogen selenide (H2Se) are involved in the reaction.
Resumo:
The presence of tissue specific precursor cells is an emerging concept in organ formation and tissue homeostasis. Several progenitors are described in the kidneys. However, their identity as a true stem cell remains elusive. Here, we identify a neonatal kidney-derived c-kit(+) cell population that fulfills all of the criteria as a stem cell. These cells were found in the thick ascending limb of Henle's loop and exhibited clonogenicity, self-renewal, and multipotentiality with differentiation capacity into mesoderm and ectoderm progeny. Additionally, c-kit(+) cells formed spheres in nonadherent conditions when plated at clonal density and expressed markers of stem cells, progenitors, and differentiated cells. Ex vivo expanded c-kit(+) cells integrated into several compartments of the kidney, including tubules, vessels, and glomeruli, and contributed to functional and morphological improvement of the kidney following acute ischemia-reperfusion injury in rats. Together, these findings document a novel neonatal rat kidney c-kit(+) stem cell population that can be isolated, expanded, cloned, differentiated, and used for kidney repair following acute kidney injury. These cells have important biological and therapeutic implications. STEM Cells 2013;31:1644-1656
Resumo:
Celem artykułu jest przedstawienie projektu o charakterze badawczo-wdrożeniowym dotyczącego doskonalenia obcojęzycznych kompetencji mownych (wypowiadanie się i rozumienie wypowiedzi ustnych) na poziomie zaawansowanym i przygotowywanym w Instytucie Filologii Romańskiej UAM. Niniejszy projekt zakłada, że istnieją spore możliwości podniesienia skuteczności i ekonomii kształcenia kompetencji mownych, poprzez zintegrowane podejście do celów kształcenia, a także poprzez wykorzystanie narzędzi internetowych. Podejście to zasadza się na integracji trzech zakresów kształcenia, a mianowicie: (1) doskonalenia umiejętności interakcyjnych w zakresie komunikacji półpublicznej, (2) rozwoju kompetencji medialnej oraz (3) rozwoju wiedzy dot. aktualnej, szeroko pojmowanej problematyki społeczno-kulturowej i krytycznego, zobiektywizowanego myślenia w stosunku do prezentowanych ujęć i naświetleń tej problematyki. W niniejszym omówieniu główny nacisk położony zostanie na uargumentowanie zasadności postulowanego zintegrowanego podejścia dyskursywnego, a także na wykazanie wartości dydaktycznej wybranych audycji medialnych. Zaprezentowane zostaną również główne kierunki pracy dydaktycznej oraz wyniki badania pilotażowego.