Nanostructured Ga doped ZnO thin films prepared by Sol-Gel spin-Coating / Filmes finos de ZnO NanoestruturadoS Ga doped preparados por sol-Gel spin-Coating

ZnO nanostructures are used in device systems such as photodetectors, gas sensors,photoemission devices, UV-photosensors and many others in Optoelectronics.In the present work we studied nanocrystalline ZnO:Ga thin films prepared by the sol–gel dip-coating technique. Samples were characterized by Grazing Incidence X-ray Diffraction(GIXD), X-ray Reflectivity (XR) and Grazing Incidence Small-Angle X-ray Scattering(GISAXS) methods and Field Effect Scanning Electronic Microscopy (FESEM). Characterization of the samples shows that the obtained films were uniform, continuous, with a crystallite size around 12 nm, an average pores size of around 3.5nm, and a volume fraction of nanoporosity between 0.18 and 0.3. Comparison of densities between doped and undoped films is discussed

Uv photoresponse of ZnO films measured over long periods

El ZnO es un material semiconductor tipo n con una alta energía de ligadura excitónica (60 meV) y un bandgap directo de 3,37 eV. Esta última característica hace que se lo considere un material fotoconductivo, apto para la detección UV. La fotoconductividad es una propiedad importante en los sólidos por medio de la cual la conductividad global de la muestra cambia debido a la radiación incidente. En general esta propiedad es un proceso complejo que incluye la generación y recombinación de portadores de carga y su transporte a los electrodos. En el caso del ZnO, la interpretación de la fotoconductividad resulta particularmente dificultosa por el hecho que, además de los mencionados, ocurren simultáneamente otros procesos, entre ellos la absorción y desorción de oxígeno sobre la superficie. En el presente trabajo se estudió la fotorespuesta de films de ZnO nanoestructurados obtenidos por el método de sol-gel y depositados por spin-coating, para tiempos largos de exposición a la radiación o en oscuridad. En los gráficos obtenidos de resistencia vs. tiempo se observa que, tanto en el pasaje desde la oscuridad hacia la iluminación UV, como a la inversa, hay un efecto de cambio de tendencia en el comportamiento de la curva luego de un período de horas. La mayoría de los trabajos existentes en literatura se relacionan con las características de dispositivos detectores de UV en tiempos muy breves de exposición-oscuridad (no mayores a algunos minutos). En los trabajos existentes con mediciones a tiempos largos no se hace mención a este comportamiento. Se discuten posibles mecanismos involucrados.ZnO is an n-type semiconductor material with a high exciton binding energy (60 meV) and a direct bandgap of 3.37 eV. This last characteristic makes it considered a photoconductive material, suitable for UV detection. Photoconductivity is an important property in solids whereby the overall conductivity of the sample changes due to incident radiation. In general, this property is a complex process that includes the generation and recombination of charge carriers and their transport to the electrodes. In the case of ZnO, the interpretation of photoconductivity is particularly difficult due to the fact that, in addition to the aforementioned effects, other processes occur simultaneously, including the absorption and desorption of oxygen on the surface. In the present work, the photo response of nanostructured ZnO films obtained by the sol-gel method and deposited by spin-coating, was studied for long times of exposure to radiation or in the dark. On the resistance vs. time curves, it is observed that, both in the passage from darkness to UV illumination and vice versa, there are changes in the behavior of the curve after a period of hours. Most of the existing works in the literature are related to the characteristics of UV detection devices in very short exposure-dark times (no longer than a few minutes). In the existing works with measurements at long times, there is no mention about this behavior. Possible mechanisms involved are discussed.Fil: Bojorge, Claudia Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Bianchetti, Mario Fidel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Heredia, Eduardo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Canepa, Horacio Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentin

Simulation of Single Crystalline CdZnTe Solidification Process

Single crystals of Cd1-xZnxTe (0 ≤ x ≤ 0.1) (CZT/CdZnTe) are used in manufacture of gamma and X-ray detectors and as substrates for epitaxial growth of HgCdTe. Computer simulation for the solidification of CZT was performed using finite elements. The simulation results indicate that a lower translation speed of the quartz ampoule within the Bridgman furnace determines a lower concavity of the liquid interface which assures a good crystalline quality. When the rate is 3.32 mm/h the concavity is 58% greater than for a speed of 0.50 mm/h. It was experimentally found that when growing at low speed, 1.66 mm/h, the process is more stable and improves the crystalline quality due that only two grains were generated in CZT ingots. Meanwhile a faster growth speed- 3.32 mm/h- generates a large amount of grains in the CZT ingot.Fil: Martinez, Ana Maria. Provincia de Misiones. Comite de Desarrollo E Innovacion Tecnologica; ArgentinaFil: Rosenberger, Mario Roberto. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico Nordeste. Instituto de Materiales de Misiones; ArgentinaFil: Trigubo, Alicia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégicos Para la Defensa; Argentina. Universidad Tecnologica Nacional; ArgentinaFil: D'elia, Raul Luis. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; ArgentinaFil: Heredia, Eduardo Armando. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas Para la Defensa; Argentin

Doping of nanocrystalline SnO2 for high sensitivity resistivity sensors to detect H2S (g) in air

In this work, several factors to increase the sensitivity of a high precision resistive type sensor able todetect from (10 to 15) ppm de H2S (g) in air, are considered. It is accepted that the doping of the material sensor (SnO2) increases the dispositive sensibility. Several dopants were proved, concluding that the CuO was the most convenient. Several papers are found in the bibliography presenting different techniques to dope the material sensor but, in this work, an own developed at DEINSO technique was employed, in which the dopant is homogeneously distributed in the SnO2 crystalline lattice. At first, it was proposed to dope the nanocrystalline SnO2 with different CuO concentrations (1 %wt. 5 %wt. and 6 %wt.) to choose the most convenient one, which resulted 5 % wt. CuO. Under these conditions, a more sensible sensor was built and other factors were studied to increase even more the sensitivity. The 5 %wt CuO-SnO2 was deposited on thin films (or layers) forming a multilayers system (which employed from three to six layers or superimposed thin films). The sensor material was characterized with different techniques, such as: DRX, SEM-EDS and GISAXS, which enabled to determinethe mean crystallite size, the multilayer system thickness, the crystallinity, the chemical composition and the layers porosity. With the built sensor, (10 to 15) ppm of H2S (g) in air concentration was measured at an operation temperature (To) of 140 ºC. This finding enabled to solve the request of an ambiance security sensor for the oil cracking plant of an important Argentine oil company.The following subject is not included in this paper but, it is interesting to inform that higher sensitivity of the same described sensor it was possible to detect concentrations from (4 - 5) ppm of H2S (g) in air at To=~ 30 ºC, which makes possible to build a medical use sensor to detect H2S (g) very low concentrations (minor than 5ppm) which are found in halitosis of hepatic maladies.Fil: Poiasina, Mariana Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto Sabato; ArgentinaFil: Bianchetti, Mario Fidel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Heredia, Eduardo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Canepa, Horacio Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Walsöe de Reca, Noemi E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentin

Structural quality in single crystalline CdSe ingots grown by PVT: Qualidade estrutural em lingotes de CdSe monocristalinos crescidos por PVT

CdSe is II-VI semiconductor with compact hexagonal structure. It has a band gap of 1.82 eV and a high stopping power for nuclear radiation. Single crystalline CdSe ingots were grown by Physical Vapor Transport (PVT) employing a horizontal reactor. As devices critically depend on material properties its single crystalline quality was determined by chemical etching and transmission electron microscopy. Results were compared to those corresponding to Bridgman High Pressure (HPB) grown material and also to PVT material grown in a vertical reactor.O CdSe é um semicondutor II-VI com estrutura hexagonal compacta. Tem uma banda proibida de 1,82 eV e um alto poder de freamento de radiação nuclear. Os monocristais de CdSe foram crescidos por transporte físico de vapor (PVT), empregando um reator horizontal. Como os dispositivos dependem criticamente das propriedades do material, sua qualidade cristalina foi determinada por ataque químico e microscopia eletrônica de transmissão. Os resultados foram comparados com aqueles correspondentes ao material crescido pelo método Bridgman vertical de alta pressão (HPB) e também com o material PVT crescido em um reator vertical.Fil: D'Elía, Raúl Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Aguirre Myriam Haydee. Universidad de Zaragoza. Facultad de Ciencias. Departamento de Física de la Materia Condensada; EspañaFil: Di Stefano, María Cristina. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires; ArgentinaFil: Heredia, Eduardo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Martínez, Ana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires; ArgentinaFil: Canepa, Horacio Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Núñez García, Javier Luis Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires; ArgentinaFil: Trigubo, Alicia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires; Argentin

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Penilaian Kinerja Keuangan Koperasi di Kabupaten Pelalawan

This paper describe development and financial performance of cooperative in District Pelalawan among 2007 - 2008. Studies on primary and secondary cooperative in 12 sub-districts. Method in this stady use performance measuring of productivity, efficiency, growth, liquidity, and solvability of cooperative. Productivity of cooperative in Pelalawan was highly but efficiency still low. Profit and income were highly, even liquidity of cooperative very high, and solvability was good

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI

Search for stop and higgsino production using diphoton Higgs boson decays

Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top-quark (stop) and the Higgs boson (higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets. In 19.7 inverse femtobarns of proton-proton collision data at sqrt(s) = 8 TeV, recorded in the CMS experiment, no evidence of a signal is found and lower limits at the 95% confidence level are set, excluding the stop mass below 360 to 410 GeV, depending on the higgsino mass