988 resultados para 630
Resumo:
Parte 1 - Atos do Poder Legislativo
Resumo:
纳米氧化锌(ZnO)是一种直接宽带隙半导体材料,室温下其禁带隙宽为本3.37 eV,激子束缚能为60 meV。纳米ZnO有明显的尺寸效应、表面和界面效应等,物理化学性能优越。在压电材料、铁电材料、平面显示、表面声波、传感器、场发射器件、激光、光催化等方面有着广泛的用途。近年来,对纳米ZnO材料的研究成为国内外的一个热点。 本论文研究了用化学气相沉积(CVD)法制备微/纳米ZnO材料。通过控制实验条件,合成了多种特殊结构和形貌的微/纳米ZnO材料,并用扫描电子显微镜(SEM)、高分辨率透射电镜(HR-TEM)、X-射线衍射仪(XRD)、Raman光谱和光致发光(PL)等对材料的结构和光学性能进行了表征。采用CVD法,在温度为630 °C,氧气流量为15 sccm,氩气流量为300 sccm的条件下,制备了一种纳米带冠四足状ZnO(T-ZnO)。此结构ZnO材料的每根足顶端均有一规则的六方帽形结构,具有很大的比表面积。实验结果表明:合成的ZnO材料为纤维锌矿结构单晶,并且沿着(0001)方向生长;室温下的PL谱有两个激发峰,一个是在393 nm处相对较弱的近带紫外峰,另一个是在511 nm处强峰。而材料在600 °C下氧气中退火30 min后,511 nm附近的绿光激发辐射峰则基本消失了,这说明在511 nm处的绿光激发辐射峰可能是由于氧空位引起的。此外,通过改变实验条件,还得到了其他多种结构的微/纳米ZnO材料。 通过大量实验,找到了一种在低温下合成微/纳米ZnO材料的新方法,即水蒸气氧化法。用ZnI2作为锌源,水蒸气作为氧化剂,实验温度在300~500 °C范围内,大大低于通常CVD法的500~1500 °C。采用此法,用硅做基底,得到了一系列有趣的实验结果,大多数情况下ZnO纳米晶自组装成很规则的圆。而在瓷舟中收集到的纳米ZnO跟普通CVD法结果相似,可以得到锥状、棒状等结构的纳米晶,但其生长方式与硅基底上的有很大差别。此外,用水蒸气氧化法,还实现了ZnO纳米晶在碳纳米管(CNTs)上的直接生长,而且其PL性能增强,这可能是纳米ZnO和CNTs相互耦合的结果。在700 °C温度下,以锌粉和ZnI2作为锌源,用水蒸气作为氧化剂,在硅基底的正反面分别得到了纳米棒和纳米推子阵列。此外,还对水蒸气氧化法的化学反应机理进行了分析,实验结果证明:固态ZnI2在受热和一定真空度下先蒸发成ZnI2分子,ZnI2分子遇到水蒸气发生反应生成偶极ZnO分子,这些ZnO偶极分子在硅基底上通过静电力自组装成特殊的几何形状。 此外,还通过分子动力学模拟的方法,对材料的力学性能进行了研究,得到了ZnO的弹性常数和体弹性模量,模拟值跟其他研究人员的实验和模拟结果吻合得很好,并估出算了ZnO晶体的表面能和断裂韧性。 本论文还对制备材料的光催化性能进行了系统的研究,采用CVD法制备ZnO,对铬黑T(EBT)进行光催化降解实验。通过正交实验方法,得到了ZnO催化降解EBT的最佳工艺条件,即催化剂用量为5 g/L,光照强度为120 W,反应温度为20 °C,反应时间为120 min,EBT浓度为10 mg/L,溶液pH值为4。 在最佳实验条件下,20分钟内有95%的EBT被降解完,30分钟内则全部降解。因此,ZnO在EBT的降解中催化效率很高,在废水处理中具有潜在的应用前景。
Resumo:
This paper aims at investigating the size-dependent self-buckling and bending behaviors of nano plates through incorporating surface elasticity into the elasticity with residual stress fields. In the absence of external loading, positive surface tension induces a compressive residual stress field in the bulk of the nano plate and there may be self-equilibrium states corresponding to the plate self-buckling. The self-instability of nano plates is investigated and the critical self-instability size of simply supported rectangular nano plates is determined. In addition, the residual stress field in the bulk of the nano plate is usually neglected in the existing literatures, where the elastic response of the bulk is often described by the classical Hooke’s law. The present paper considered the effect of the residual stress in the bulk induced by surface tension and adopted the elasticity with residual stress fields to study the bending behaviors of nano plates without buckling. The present results show that the surface effects only modify the coefficients in corresponding equations of the classical Kirchhoff plate theory.
Resumo:
170 p. : il., graf.
Resumo:
HIGHLIGHTS FOR FY 2005 1. Assisted with a study to assess hurricane impacts to Gulf sturgeon critical foraging habitat. 2. Documented Gulf sturgeon marine movement and habitat use in the Gulf of Mexico. 3. Documented Gulf sturgeon spawning with the collection of fertilized eggs in the Apalachicola River, Florida. 4. Documented Gulf sturgeon spawning with the collection of fertilized eggs in the Yellow River, Florida. 5. Assisted with benthic invertebrate survey at Gulf sturgeon marine foraging grounds. 6. Implemented Gulf Striped Bass Restoration Plan by coordinating the 22nd Annual Morone Workshop, leading the technical committee, transporting broodfish, and coordinating the stocking on the Apalachicola-Chattahoochee-Flint (ACF) river system. 7. Over 87,000 Phase II Gulf striped bass were marked with sequential coded wire tags and stocked in the Apalachicola River. Post-stocking evaluations were conducted at 45 sites in the fall and spring and 8 thermal refuges in the summer. 8. Completed fishery surveys on 4 ponds on Eglin AFB totaling 53 acres, and completed a report with recommendations for future recreational fishery needs. 9. Completed final report for aquatic monitoring at Eglin AFB from 1999 to 2004. 10. Completed a field collection of the endangered Okaloosa darter to be incorporated into a status review to be completed in FY06. 11. Provided technical assistance to the Region 4 National Wildlife Refuge (NWR) program on changes to the fishery conservation targets for the region. Also provided technical assistance to four NWRs (i.e., Okefenokee NWR, Banks Lake NWR, St. Vincent NWR, and St. Marks NWR) relative to hurricanes and recreational fishing. 12. A draft mussel sampling protocol was tested in wadeable streams in Northwest Florida and southwest Georgia, and an associated field guide, poster, and Freshwater Mussel Survey Protocol and Identification workshop were completed in FY05. 13. Implemented recovery plan and candidate conservation actions for 14 listed and candidate freshwater mussels in the Northeast Gulf Watersheds. 14. Initiated or completed multiple stream restoration and watershed management projects. A total of 7.5 stream miles were restored for stream fishes, and 11 miles of coastline were enhanced for sea turtle lighting. A total of 630 acres of wetlands and 2,401 acres of understory habitat were restored. 15. Conducted a watershed assessment to develop a threats analysis for prioritizing restoration, protection, and enhancement to natural resources of Spring Creek, Georgia and Canoe Creek, Florida. 16. Continued the formation of an Unpaved Road Interagency Team of Federal, State, and local agencies in Northwest Florida to promote stream protection and restoration from unpaved road sediment runoff. Began the development of a technical committee agreement. 17. Conducted Alabama Unpaved Road Inventory within the Northeast Gulf Ecosystem. Data collection will be completed during FY06. 18. Finalized the development of two North Florida hydrophysiographic regional curves for use by the Florida Department of Transportation (DOT) and others involved with stream restoration and protection. Initiated the development of the Alabama Coastal Plain Riparian Reference Reach and Regional Curves for use by the Alabama Department of Environmental Management (ADEM). 19. Provided technical assistance in collecting data, analysis, and thesis formulation with Troy University, Alabama, to identify the influence of large woody debris in southeastern coastal plain streams. 20. Completed pre- and post-restoration fish community monitoring at several restoration projects including Big Escambia Creek, Magnolia Creek, and Oyster Lake, Florida. 21. Established a watershed partnership for the Chipola River in Alabama and Florida and expanded development and participation in the Spring Creek Watershed Partnership, Georgia. 22. Continued to identify barriers which inhibit the movement of aquatic species within the Northeast Gulf Ecoregion. 23. Completed a report on road crossing structures in Okaloosa darter streams to guide the closure/repair/maintenance of roads to contribute to recovery of the endangered species. In cooperation with Three Rivers RC&D Council, fish passage sites identified in the report were prioritized for restoration. 24. Monitored Aquatic Nuisance Species in the Apalachicola River and tested the sterility of exotic grass carp. 25. Multiple outreach projects were completed to detail aquatic resources conservation needs and opportunities. Participated in National Fishing Week event, several festivals, and school outreach.
Resumo:
Shellfish bed closures along the North Carolina coast have increased over the years seemingly concurrent with increases in population (Mallin 2000). More and faster flowing storm water has come to mean more bacteria, and fecal indicator bacterial (FIB) standards for shellfish harvesting are often exceeded when no source of contamination is readily apparent (Kator and Rhodes, 1994). Could management reduce bacterial loads if the source of the bacteria where known? Several potentially useful methods for differentiating human versus animal pollution sources have emerged including Ribotyping and Multiple Antibiotic Resistance (MAR) (US EPA, 2005). Total Maximum Daily Load (TMDL) studies on bacterial sources have been conducted for streams in NC mountain and Piedmont areas (U.S. EPA, 1991 and 2005) and are likely to be mandated for coastal waters. TMDL analysis estimates allowable pollutant loads and allocates them to known sources so management actions may be taken to restore water to its intended uses (U.S. EPA, 1991 and 2005). This project sought first to quantify and compare fecal contamination levels for three different types of land use on the coast, and second, to apply MAR and ribotyping techniques and assess their effectiveness for indentifying bacterial sources. Third, results from these studies would be applied to one watershed to develop a case study coastal TMDL. All three watershed study areas are within Carteret County, North Carolina. Jumping Run Creek and Pettiford Creek are within the White Oak River Basin management unit whereas the South River falls within the Neuse River Basin. Jumping Run Creek watershed encompasses approximately 320 ha. Its watershed was a dense, coastal pocosin on sandy, relic dune ridges, but current land uses are primarily medium density residential. Pettiford Creek is in the Croatan National Forest, is 1133 ha. and is basically undeveloped. The third study area is on Open Grounds Farm in the South River watershed. Half of the 630 ha. watershed is under cultivation with most under active water control (flashboard risers). The remaining portion is forested silviculture.(PDF contains 4 pages)
Resumo:
We investigate the higher spectral component generations driven by a few-cycle laser pulse in a dense medium when a static electric field is present. Our results show that, when assisted by a static electric field, the dependence of the transmitted laser spectrum on the carrier-envelope phase (CEP) is significantly increased. Continuum and distinct peaks can be achieved by controlling the CEP of the few-cycle ultrashort laser pulse. Such a strong variation is due to the fact that the presence of the static electric field modifies the waveform of the combined electric field, which further affects the spectral distribution of the generated higher spectral components.
Resumo:
The initial objective of Part I was to determine the nature of upper mantle discontinuities, the average velocities through the mantle, and differences between mantle structure under continents and oceans by the use of P'dP', the seismic core phase P'P' (PKPPKP) that reflects at depth d in the mantle. In order to accomplish this, it was found necessary to also investigate core phases themselves and their inferences on core structure. P'dP' at both single stations and at the LASA array in Montana indicates that the following zones are candidates for discontinuities with varying degrees of confidence: 800-950 km, weak; 630-670 km, strongest; 500-600 km, strong but interpretation in doubt; 350-415 km, fair; 280-300 km, strong, varying in depth; 100-200 km, strong, varying in depth, may be the bottom of the low-velocity zone. It is estimated that a single station cannot easily discriminate between asymmetric P'P' and P'dP' for lead times of about 30 sec from the main P'P' phase, but the LASA array reduces this uncertainty range to less than 10 sec. The problems of scatter of P'P' main-phase times, mainly due to asymmetric P'P', incorrect identification of the branch, and lack of the proper velocity structure at the velocity point, are avoided and the analysis shows that one-way travel of P waves through oceanic mantle is delayed by 0.65 to 0.95 sec relative to United States mid-continental mantle.
A new P-wave velocity core model is constructed from observed times, dt/dΔ's, and relative amplitudes of P'; the observed times of SKS, SKKS, and PKiKP; and a new mantle-velocity determination by Jordan and Anderson. The new core model is smooth except for a discontinuity at the inner-core boundary determined to be at a radius of 1215 km. Short-period amplitude data do not require the inner core Q to be significantly lower than that of the outer core. Several lines of evidence show that most, if not all, of the arrivals preceding the DF branch of P' at distances shorter than 143° are due to scattering as proposed by Haddon and not due to spherically symmetric discontinuities just above the inner core as previously believed. Calculation of the travel-time distribution of scattered phases and comparison with published data show that the strongest scattering takes place at or near the core-mantle boundary close to the seismic station.
In Part II, the largest events in the San Fernando earthquake series, initiated by the main shock at 14 00 41.8 GMT on February 9, 1971, were chosen for analysis from the first three months of activity, 87 events in all. The initial rupture location coincides with the lower, northernmost edge of the main north-dipping thrust fault and the aftershock distribution. The best focal mechanism fit to the main shock P-wave first motions constrains the fault plane parameters to: strike, N 67° (± 6°) W; dip, 52° (± 3°) NE; rake, 72° (67°-95°) left lateral. Focal mechanisms of the aftershocks clearly outline a downstep of the western edge of the main thrust fault surface along a northeast-trending flexure. Faulting on this downstep is left-lateral strike-slip and dominates the strain release of the aftershock series, which indicates that the downstep limited the main event rupture on the west. The main thrust fault surface dips at about 35° to the northeast at shallow depths and probably steepens to 50° below a depth of 8 km. This steep dip at depth is a characteristic of other thrust faults in the Transverse Ranges and indicates the presence at depth of laterally-varying vertical forces that are probably due to buckling or overriding that causes some upward redirection of a dominant north-south horizontal compression. Two sets of events exhibit normal dip-slip motion with shallow hypocenters and correlate with areas of ground subsidence deduced from gravity data. Several lines of evidence indicate that a horizontal compressional stress in a north or north-northwest direction was added to the stresses in the aftershock area 12 days after the main shock. After this change, events were contained in bursts along the downstep and sequencing within the bursts provides evidence for an earthquake-triggering phenomenon that propagates with speeds of 5 to 15 km/day. Seismicity before the San Fernando series and the mapped structure of the area suggest that the downstep of the main fault surface is not a localized discontinuity but is part of a zone of weakness extending from Point Dume, near Malibu, to Palmdale on the San Andreas fault. This zone is interpreted as a decoupling boundary between crustal blocks that permits them to deform separately in the prevalent crustal-shortening mode of the Transverse Ranges region.
Resumo:
Time-of-flight measurements of energetic He atoms, field ionization of cryogenic liquid helium clusters, and time-of-flight and REMPI spectroscopy of radical salt clusters were investigated experimentally. The excited He atoms were generated in a corona discharge. Two strong neutral peaks were observed, accompanied by a prompt photon peak and a charged peak. All peaks were correlated with the pulsing of the discharge. The neutral hyperthermal and metastable atoms were formed by different mechanisms at different stages of the corona discharge. Positively charged helium droplets were produced by ionization of liquid helium in an electrostatic spraying experiment. The fluid emerging from a thin glass capillary was ionized by a high voltage applied to a needle inside the capillary. Fine droplets (less than 10 µm in diameter) were produced in showers with currents as high as 0.4 µA at 2-4 kV. The high currents resulting from field ionization in helium and the low surface tension of He I, led to charge densities that greatly exceeded the Rayleigh limit, thus resulting in coulombic explosion of the liquid. In contrast, liquid nitrogen formed a well-defined Taylor cone with droplets having diameters comparable to the jet (≈100 µm) at lower currents (10 nA) and higher voltages (8 kV). The metal-halide clusters of calcium and chlorine were generated by laser ablation of calcium metal in a Ar/CCl4 expansion. A visible spectrum of the Ca2Cl3 cluster was observed from 651 to 630 nm by 1 +1' REMPI. The spectra were composed of a strong origin band at 15 350.8 cm-1 and several weak vibronic bands. Density functional calculations predicted three minimum energy isomers. The spectrum was assigned to the 2B2 ← X 2A1 transition of a planar C2V structure having a ring of two Cl and two Ca atoms and a terminal Cl atom. The ring isomer of Ca2Cl3 has the unpaired electron localized on one Ca2+ ion to form a Ca+ chromophore. A second electronic band of Ca2Cl3 was observed at 720 nm. The band is sharply different from the 650 nm band and likely due to a different isomer.
Resumo:
The term "polarization-dependent Talbot effect" means that the Talbot self-imaging intensity of a high-density grating is different for TE and TM polarization modes. Numerical simulations with the finite-difference time-domain method show that the polarization dependence of the Talbot images is obvious for gratings with period d between 2 lambda and 3 lambda. Such a polarization-dependent difference for TE and TM polarization of, a high-density grating of 630 lines/mm (corresponding to d/lambda = 2.5) is verified through experiments with the scanning near-field optical microscopy technique, in which a He-Ne laser is used as its polarization is changed from the TE mode to the TM mode. The polarization-dependent Talbot effect should help us to understand more clearly the diffraction behavior of a high-density grating in nano-optics and contribute to wide application of the Talbot effect. (c) 2006 Optical Society of America.
Resumo:
O estudo das causas múltiplas de óbitos permite conhecer a extensão real das estatísticas de mortalidade, minimizando a subestimação dos dados de mortalidade por asma. O objetivo desta pesquisa foi avaliar a tendência das taxas de mortalidade por asma informada em qualquer linha ou parte do atestado médico da declaração de óbito, no município do Rio de Janeiro, no período de 2000-2009. Os dados foram obtidos no Sistema de Informações de Mortalidade (SIM), no período de 2000 a 2009, nas Declarações de Óbitos (DO) registradas com CID-10 J45 e J46, de residentes do município do Rio de Janeiro, com um ano ou mais de idade. Foram calculadas taxas de mortalidade padronizadas por idade, nas seguintes faixas etárias: 1-4 anos, 5-34 anos, 35-59 anos, 60 e mais anos, considerando-se asma como causa básica e como causas múltiplas, segundo gênero para cada ano do período. Para análise de dados foi utilizado a técnica de regressão linear. No período de 10 anos a asma foi causa básica em 67,2% dos óbitos que mencionaram asma. A subestimação da mortalidade por asma como causa básica, foi igual a 48,7%. A taxa de mortalidade padronizada por asma como causa básica declinou de 2000 a 2009 de 2,22 para 1,72/100.000 habitantes em 2009, (β= -0.06, p=0.017) e como causas múltiplas passou de 3,45 para 2,82/100.000 habitantes (β= -0.11, p=0.005). A análise segundo gênero evidenciou um declínio mais acentuado entre os homens, cuja taxa de mortalidade por asma como causa básica padronizada passou de 1,58/100.000 em 2000 para 0,59/100.000 em 2009 (β= -0.08, p=0.007); como causa múltipla a taxa diminuiu de 2,49/100.000 em 2000 para 1,11/100.000 em 2009 (β= -0.14, p<0.00001). Entre as mulheres a taxa de mortalidade passou de 2,79/100.000 em 2000 para 2,72/100.000 em 2009 como causa básica e de 4,29/100.000 em 2000 para 4,32/100.000 em 2009. A regressão linear segmentada, realizada em dois períodos, de 2000 a 2004 e 2004 a 2009, não foi estatisticamente significativa (2000 a 2004: β= -0,16, p=0,131 e 2004 a 2009: β= 0,04, p=0,630). Do total de óbitos nos quais a asma foi mencionada como causa múltipla 2,8% ocorreram na idade de 1 a 4 anos e 61% na faixa de 60 anos e mais. Quando a asma foi causa básica, as causas associadas mais frequentes foram as doenças do aparelho respiratório e nos óbitos em que foi classificada como causa associada destacaram-se como causas básicas as doenças do aparelho respiratório e circulatório. A magnitude das taxas de mortalidade por asma foi sempre maior nas mulheres comparado aos homens. A série histórica mostrou tendência ao declínio nas taxas de mortalidade, segundo causas básicas e múltiplas, com declínio entre os homens e estabilidade entre as mulheres. A mortalidade por asma foi subestimada quando considerada apenas como causa básica, o que poderia ser evitado com a utilização da metodologia de causas múltiplas nas estatísticas de mortalidade da asma.
Resumo:
Red bream (Beryx decadactylus) is a commercially important deep-sea benthopelagic fish with a circumglobal distribution on insular and continental slopes and seamounts. In the United States, small numbers are caught incidentally in the wreckfish (Polyprion americanus) fishery which operates off the southeastern coast, but no biological information exists for the management of the U.S. red bream population. For this study, otoliths (n=163) and gonads (n=161) were collected from commercially caught red bream between 2003 and 2008 to determine life history parameters. Specimens ranged in size from 410 to 630 mm fork length and were all determined to be mature by histological examination of the gonads. Females in spawning condition were observed from June through September, and reproductively active males were found year-round. Sectioned otoliths were difficult to interpret, but maximum age estimates were much higher than the 15 years previously reported for this species from the eastern North Atlantic based on whole-otolith analysis. Estimated ages ranged from 8 to 69 years, and a minimum lifespan of 49 years was validated by using bomb radiocarbon dating. Natural mortality was estimated at 0.06/yr. This study shows that red bream are longer lived and more vulnerable to overfishing than previously assumed and should be managed carefully to prevent overexploitation.
Resumo:
A importância do transporte aquaviário é dada pelos diferentes modos de navegação, podendo ser por meio fluvial, lacustre e navegação marítima. Para a logística e economia brasileira, este é um modal extremamente importante, haja vista a pluralidade de transporte pelo fato das relações de exportação e importação ocorrerem especialmente por este tipo de modal. No Brasil há cinco modalidades de transportes: o aquaviário, o rodoviário, o aeroviário, o ferroviário e o dutoviário. Serão descritas nos próximos capítulos as características de cada tipo de modal, especificamente dos modais rodoviário e aquaviário, em especial a cabotagem, objeto principal deste estudo. O objetivo deste trabalho é analisar a atual situação do transporte marítimo no Brasil, especialmente a cabotagem. Através de três parâmetros - custos, tempo de viagem e segurança -, procurar-se-á avaliar o nível de qualidade do modal, visando à identificação da existência de pontos críticos e sugerir possíveis soluções baseadas na logística e na tecnologia, ferramentas fundamentais para a busca da eficácia na redução dos custos de transportes, contribuindo para um melhor resultado dos custos logísticos finais. Para uma reflexão sobre o transporte nacional de mercadorias por via marítima através da cabotagem, serão apresentadas as características principais do transporte marítimo, com suas vantagens e desvantagens e sua importância para a economia brasileira. A crítica envolverá a questão do frete marítimo e suas interrelações, discutindo variáveis que compõem o preço do frete. Ferramentas tecnológicas fundamentais para a eficácia das operações também serão abordadas durante este trabalho. Serão descritas as características dos portos brasileiros, em especial as dos portos do Rio Grande (RS), Santos (SP), Suape (PE) e Rio de Janeiro (RJ), a distancia entre o porto do Rio de Janeiro (RJ) e os demais, bem como o tempo de viagem relacionado entre eles. Explorado pela União diretamente ou mediante concessão (precedida de licitação), o porto organizado, construído e aparelhado para atender necessidades da navegação e da movimentação é administrado pelo Conselho de Autoridade Portuária - CAP -, contando ainda com a figura do OGMO Orgão Gestor de Mão de Obra que controla a força de trabalho nas áreas portuárias, organismos instituídos pela Lei n. 8.630, de 25 de fevereiro de 1993, chamada da Lei de Modernização dos Portos. Por fim serão analisadas as variáveis custo, tempo de viagem e segurança no intuito de contribuir para uma reflexão para o crescimento do transporte de cabotagem no Brasil, procurando identificar um ganho substancial na economia brasileira, através da economia de escala, observados todos os parâmetros necessários para o bom desenvolvimento da logística de transporte de mercadorias por via marítima. Este trabalho abordará a Gestão do Transporte Marítimo de Cargas no Brasil, em especial a cabotagem.