915 resultados para High quality (HQ)
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[Es]Introducción: actualmente, en servicios como UCIs, quirófanos y Urgencias cada vez es más común el empleo de CVCS y PICC. Ambos están asociados a graves complicaciones como CLABSI, TVP, EP, arritmia, etc. Dado que la enfermería juega un papel importante tanto en la inserción de estos dispositivos, como en el mantenimiento y prevención de las adversidades, es necesario poseer los conocimientos y habilidades adecuados para su afrontamiento. Objetivo y metodología: determinar cuál de los dos supone menor riesgo de complicaciones en pacientes críticos mediante la evidencia científica y utilizando la EBE. Para ello se ha realizado una revisión bibliográfica de estudios encontrados en bases de datos como Pubmed, Cochrane y Cinhal mediante la combinación de términos MeSH y palabras clave con operadores booleanos. Resultados y discusión: se han incluido en total 13 publicaciones (6 RS, 4 estudios de cohorte, 1 ECA y 2 GPC), de las cuales 3 poseen calidad alta, 3 media y 5 baja. Tanto los PICC como los CVCS implican diversas complicaciones, divididas en infecciosas, trombo-embolicas y mecánicas/otras. Existe insuficiente evidencia científica y gran heterogeneidad entre los artículos, lo que dificulta su extrapolación. Conclusiones: en pacientes críticos los PICC poseen mayor riesgo de TVP, los CVCS de complicaciones mecánicas, y ambos presentan tasas similares de CLABSI. Es importante escoger de forma individualizada el catéter a implantar, estimando los riesgos-beneficios de cada uno. Los cuidados preventivos son fundamentales en la reducción de estas contingencias. Son necesarios más estudios prospectivos comparativos.
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Nosso objetivo neste trabalho é investigar como o design gráfico se relaciona com os meios de produção da indústria gráfica brasileira. Não é comum encontrar referências abordando temas que relacionam design e tecnologia em livros sobre a história do Brasil, o que demonstra a urgência do resgate histórico de indústrias que implementaram novas tecnologias para atender a demandas projetuais e mercadológicas. Sediada na cidade do Rio de Janeiro, a clicheria Latt-Mayer como era comumente chamada, era sinônimo de qualidade e tecnologia. Entre seus clientes podemos apontar agências de publicidade, editoras, escritórios de designers e gráficas de todo país. Esta pesquisa se baseia em um corpus composto por imagens, documentos, manuais técnicos, reportagens, matrizes e depoimentos com pessoas que estiveram diretamente envolvidas com essa empresa. Catalogamos maquinaria e técnicas utilizadas, além de projetos gráficos relevantes que tiveram matrizes e provas produzidas na empresa. Por meio deste trabalho, é possível visualizar um abrangente painel histórico, que contempla um período em que ocorreram significativas transformações na relação entre designers e tecnologia na indústria gráfica brasileira.
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High-quality 2at%-doped Yb:CaF2 and Yb,Na:CaF2 single crystals with diameter of 76mm were grown by the temperature gradient technique. For the first time, distribution coefficients (KO) of Yb in the two crystals were determined to be 1.07 and 0.91, respectively, by measuring the Yb concentrations at the growth starting position in the as-grown boules. Absorption and emission spectra of the two different crystals were measured at room temperature. Experimental results show that Na+ ions codoping with Yb3+ as charge compensators make Yb3+ ions in CaF2 lattice to be a quasi-single-center system, and greatly suppress the deoxidization of Yb3+ to Yb2+ (c) 2005 Elsevier B.V. All rights reserved.
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Structural and optical properties were investigated for ZnO films grown on (100) and (001) gamma-LiAlO2 (LAO) substrates by pulsed laser deposition method. According XRD results, it is intuitionistic that (100) LAO is suitable for fabricating high quality ZnO film, while (001) LAO is unsuitable. The FWHM of XRD, stress in film and FWHM of UV PL spectra for ZnO films on (100) LAO show a decreasing with increasing substrate temperature from 300 to 600 degrees C. ZnO film fabricated at 600 degrees C has the greatest grain size, the smallest stress (0.47 Gpa) and PL FWHM value (similar to 85 meV). This means that the substrate temperature of 600 degrees C is optimum for ZnO film deposited on (100) LAO. Moreover, it was found that the UV PL spectra intensity of ZnO film is not only related to the grain size and stoichiometric, but also depends on the stress in the film.
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Lattice-matched (Delta(a/a) = 1.8-3.4%) (001) LiGaO2 substrates have been employed for the first time to grow ZnO thin films by pulsed-laser deposition at 350-650 degrees C with oxygen partial pressure of 20Pa. XRD shows that a highly c-axis-oriented ZnO film can be deposited on (001) LiGaO2 substrate at 500 degrees C. AFM images reveal the surfaces of as-deposited ZnO films are smooth and root-mean-square values are 6.662, 5.765 and 6.834 nm at 350, 500 and 650 degrees C, respectively. PL spectra indicate only near-band-edge UV emission appears in the curve of ZnO film deposited at 500 degrees C. The deep-level emission of ZnO film deposited at 650 degrees C probably results from Li diffusion into the film. All the results illustrate substrate temperature plays a pretty important role in obtaining ZnO film with a high quality on LiGaO2 substrate by pulsed-laser deposition. (c) 2006 Elsevier B.V. All rights reserved.
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成功制备了高质量的Nd:YAG透明陶瓷,激光测试样品的尺寸为3mm×3mm×3mm,双面抛光、未镀膜,最高连续输出能量为1003mW,斜率效率为14%.
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水热法生长了复合钛宝石(Al2O3/Ti:Al2O3)激光晶体.对外层Al2O3X射线ω扫描表明其晶体质量很高.外层生长的Al2O3和内部的钛宝石激光棒结合牢固、紧密,因而能适应高强度泵浦所带来的激光介质内部的热应力.复合激光晶体界面层带来的光损耗很小.就我们所知,这是首次用水热法生长复合激光晶体.
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High-quality Ce3+-doped Y3Al5O12 (YAG:Ce3+) phosphors were synthesized by a facile sol-gel combustion method. In this sol-gel combustion process, citric acid acts as a fuel for combustion, traps the constituent cations and reduces the diffusion length of the precursors. The XRD and FT-IR results show that YAG phase can form through sintering at 900 degrees C for 2 h. This temperature is much lower than that required to synthesize YAG phase via the solid-state reaction method. There were no intermediate phases such as YAlO3 (YAP) and Y4Al2O9 (YAM) observed in the sintering process. The average grain size of the phosphors sintered at 900-1100 degrees C is about 40 nm. With the increasing of sintering temperature, the emission intensity increases due to the improved crystalline and homogeneous distribution of Ce3+ ions. A blue shift has been observed in the Ce3+ emission spectrum of YAG:Ce3+ phosphors with increasing sintering temperatures from 900 to 1200 degrees C. It can be explained that the decrease of lattice constant affects the crystal field around Ce3+ ions. The emission intensity of 0.06Ce-doped YAG phosphors is much higher than that of the 0.04Ce and 0.02Ce ones. The red-shift at higher Ce3+ concentrations may be Ce-Ce interactions or variations in the unit cell parameters between YAG:Ce3+ and YAG. It can be concluded that the sol-gel combustion synthesis method provides a good distribution of Ce3+ activators at the molecular level in YAG matrix. (c) 2005 Elsevier B.V. All rights reserved.
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Large-sized (similar to 2 inch, 50.8 mm) gamma-UA102 single crystal has been grown by conventional Czochralski (Cz) method, but the crystal ha's a milky, dendriform center. The samples taken from transparent and milky parts were ground and examined by X-ray diffraction. All diffraction peaks could be indexed in gamma-LiAlO2. The crystal quality was characterized by X-ray rocking curve. The full-width at half-maximum (FWHM) values are 116.9 and 132.0 arcsec for transparent and milky parts, respectively. The vapor transport equilibrium (VTE) technique was introduced to modify the crystal quality. After 1000 degrees C/48 h, 1100 degrees C/48 h, 1200 degrees C/48 h VTE processes, the FWHM values dropped to 44.2 and 55.2 arcsec for transparent and milky part, respectively. The optical transmission of transparent part was greatly enhanced from 85% to 90%, and transmission of milky part from 75% to 80% in the range of 190 similar to 1900 nm at room temperature. When the VTE temperature was raised to 1300 degrees C, the sample cracked and FWHM values of transparent and milky parts were increased to 55.2 and 80.9 arcsec, respectively. By combining Cz technique with VTE technique, large-sized and high quality gamma-LiAlO2 crystal can be obtained.
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采用提拉法快速(6mm/h)生长了透明、φ45mm×50mm完整的铝酸锂晶体,但晶体中下部出现了一个树状、乳白色的核芯.分别从透明和乳白色核芯部位取样,研磨作粉末X射线衍射测试,发现两个样品所有的衍射峰均可以用γ-LiAlO2指标化.双晶摇摆曲线显示晶体透明和乳白色部位的半高宽分别为116.9arcsec和132.0axcsec,结晶质量较差.通过三步气相传输平衡法(简称VTE)处理后,透明部位半高宽值(FWHM)降至44.2arcsec,乳白色部位FWHM值降至53.3arcsec.结合快速生长和VTE
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About Phi 45 mm LiAlO2 single crystal was grown by Czochralski (Cz) technique. However, the full-width at half-maximum (FWHM) value was high to 116.9 arcsec. After three vapor transport equilibration (VTE) processes, we can obtain high-quality LiAlO2 slice with the FWHM value of 44.2 arcsec. ZnO films were fabricated on as-grown slices and after-VTE ones by pulsed laser deposition (PLD). It was found that ZnO films on the two slices have similar crystallinity, optical transmittance and optical band gap at room temperature. These results not only show that LAO substrate is suitable for ZnO growth, but also prove that the crystal quality of LAO substrate slightly affects the structural and optical properties of ZnO film.
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采用提拉法(CZ)生长了质量优异的Tm:YAG晶体.部分晶片在1000℃的空气气氛中退火25h.借助光学显微镜、扫描电子显微镜(SEM),结合化学腐蚀法,对Tm:YAG晶体退火前后(111)面的缺陷特征进行了研究.Tm:YAG晶体(111)面的位错腐蚀坑呈三角形.在偏光显微镜下观察了退火前后Tm:YAG晶体(111)面的应力双折射.同时应用高分辨X射线衍射法测定了晶体的完整性.实验结果表明,长时间空气气氛下高温退火有效降低了晶体中总的位错密度,提高了晶体质量.
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ZnO thin films were deposited on the substrates of (100) gamma-LiAlO2 at 400, 550 and 700 degrees C using pulsed laser deposition (PLD) with the fixed oxygen pressure of 20 Pa, respectively. When the substrate temperature is 400 degrees C, the grain size of the film is less than 1 mu m observed by Leitz microscope and measured by X-ray diffraction (XRD). As the substrate temperature increases to 550 degrees C, highly-preferred c-orientation and high-quality ZnO film can be attained. While the substrate temperature rises to 700 degrees C, more defects appears on the surface of film and the ZnO films become polycrystalline again possibly because more Li of the substrate diffused into the ZnO film at high substrate temperature. The photoluminescence (PL) spectra of ZnO films at room temperature show the blue emission peaks centered at 430 nm. We suggest that the blue emission corresponds to the electron transition from the level of interstitial Zn to the valence band. Meanwhile, the films grown on gamma-LiAlO2 (LAO) exhibit green emission centered at 540 nm, which seemed to be ascribed to excess zinc and/or oxygen vacancy in the ZnO films caused by diffusion of Li. from the substrates into the films during the deposition.
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采用提拉法生长了质量优异的Yb:Ca5(PO4)2F(Yb:FAP)晶体。运用化学腐蚀,光学显微镜、扫描电子显微镜以及能量散射光谱仪观察了该晶体中的生长条纹和包裹物等宏观缺陷,以及晶体的位错腐蚀形貌、位错密度及其分布情况,同时观察了晶体中亚晶界的形态。由晶体中位错的径向变化以及生长条纹可知:晶体在生长过程中为微凸界面生长。高温下CaF2的挥发造成了在晶体生长后期熔体中组分偏离化学计量比,出现组分过冷,形成包裹物。且位错密度显著增加。Yb:FAP晶体的各向异性使得晶体在(10 10)面的位错蚀坑形状、大小以