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Excess noise factor in large area avalanche photodiodes for different temperatures

Fernandes, L. M. P.; Lopes, J. A. M.; Santos, J. M. F. dos
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
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65.72%
The excess noise factor (ENF) of a large area avalanche photodiode was measured as a function of gain for different temperatures, in the -40 to 27°C range. Results show that ENF does not depend significantly with temperature attaining values of about 1.8 and 2.3 for gains of 50 and 300, respectively.; http://www.sciencedirect.com/science/article/B6TJM-4CMMX05-D/1/34a0ba40f32ddab67adeb9313913fec4

A large area timing RPC

Blanco, A.; Ferreira-Marques, R.; Finck, Ch.; Fonte, P.; Gobbi, A.; Policarpo, A.; Rozas, M.
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Artigo de Revista Científica Formato: aplication/PDF
ENG
Relevância na Pesquisa
65.72%
A large area Resistive Plate Chamber (RPC) with a total active surface of 160×10 cm2 was built and tested. The surface was segmented in two 5 cm wide strips readout on both ends with custom, very high frequency, front-end electronics.; http://www.sciencedirect.com/science/article/B6TJM-44JHY5B-8/1/909cdae0fda12f2c09d271fc07f60f5b

Paper-like electronic displays: Large-area rubber-stamped plastic sheets of electronics and microencapsulated electrophoretic inks

Rogers, John A.; Bao, Zhenan; Baldwin, Kirk; Dodabalapur, Ananth; Crone, Brian; Raju, V. R.; Kuck, Valerie; Katz, Howard; Amundson, Karl; Ewing, Jay; Drzaic, Paul
Fonte: The National Academy of Sciences Publicador: The National Academy of Sciences
Tipo: Artigo de Revista Científica
Publicado em 24/04/2001 EN
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45.78%
Electronic systems that use rugged lightweight plastics potentially offer attractive characteristics (low-cost processing, mechanical flexibility, large area coverage, etc.) that are not easily achieved with established silicon technologies. This paper summarizes work that demonstrates many of these characteristics in a realistic system: organic active matrix backplane circuits (256 transistors) for large (≈5 × 5-inch) mechanically flexible sheets of electronic paper, an emerging type of display. The success of this effort relies on new or improved processing techniques and materials for plastic electronics, including methods for (i) rubber stamping (microcontact printing) high-resolution (≈1 μm) circuits with low levels of defects and good registration over large areas, (ii) achieving low leakage with thin dielectrics deposited onto surfaces with relief, (iii) constructing high-performance organic transistors with bottom contact geometries, (iv) encapsulating these transistors, (v) depositing, in a repeatable way, organic semiconductors with uniform electrical characteristics over large areas, and (vi) low-temperature (≈100°C) annealing to increase the on/off ratios of the transistors and to improve the uniformity of their characteristics. The sophistication and flexibility of the patterning procedures...

A large-area, flexible pressure sensor matrix with organic field-effect transistors for artificial skin applications

Someya, Takao; Sekitani, Tsuyoshi; Iba, Shingo; Kato, Yusaku; Kawaguchi, Hiroshi; Sakurai, Takayasu
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
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It is now widely accepted that skin sensitivity will be very important for future robots used by humans in daily life for housekeeping and entertainment purposes. Despite this fact, relatively little progress has been made in the field of pressure recognition compared to the areas of sight and voice recognition, mainly because good artificial “electronic skin” with a large area and mechanical flexibility is not yet available. The fabrication of a sensitive skin consisting of thousands of pressure sensors would require a flexible switching matrix that cannot be realized with present silicon-based electronics. Organic field-effect transistors can substitute for such conventional electronics because organic circuits are inherently flexible and potentially ultralow in cost even for a large area. Thus, integration of organic transistors and rubber pressure sensors, both of which can be produced by low-cost processing technology such as large-area printing technology, will provide an ideal solution to realize a practical artificial skin, whose feasibility has been demonstrated in this paper. Pressure images have been taken by flexible active matrix drivers with organic transistors whose mobility reaches as high as 1.4 cm2/V·s. The device is electrically functional even when it is wrapped around a cylindrical bar with a 2-mm radius.

Effectiveness and Patient Acceptance of Halcinonide 0.1% Cream in 216g Jars for Large-area Steroid-responsive Dermatoses

Baum, Eric W.
Fonte: Matrix Medical Communications Publicador: Matrix Medical Communications
Tipo: Artigo de Revista Científica
Publicado em /04/2011 EN
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When treating patients with extensive dermatitis, total body surface area affected must be considered when prescribing topical medication. Halcinonide 0.1% cream, a class 2 topical corticosteroid, is now available in a 216g jar. This large size is convenient and cost effective for patients with large-area dermatoses. Objectives: The objectives of this study were to determine the efficacy and patient acceptance of halcinonide in 216g jars for the treatment of large-area dermatoses. Design: This study was an open-label, noncomparator trial evaluating the clinical outcomes and acceptability of halcinonide in 216g jars. Halcinonide was prescribed twice daily for up to 28 days. Measurement: Severity of dermatoses was based on investigator observations at the baseline visit and again after 28 days. Patient satisfaction was evaluated based on a questionnaire completed at the conclusion of the study. Results: Total enrollment was 40 patients. Dermatoses affected an average of 12 percent body surface area. At baseline, all patients exhibited dermatoses rated as severe or moderate. Nearly half of patients were completely cleared or almost cleared by 28 days, with all patients noting at least some improvement. Most patients agreed that they liked the way the product spread on the skin (94.7%)...

Simple room-temperature preparation of high-yield large-area graphene oxide

Huang, NM; Lim, HN; Chia, CH; Yarmo, MA; Muhamad, MR
Fonte: Dove Medical Press Publicador: Dove Medical Press
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
45.84%
Graphene has attracted much attention from researchers due to its interesting mechanical, electrochemical, and electronic properties. It has many potential applications such as polymer filler, sensor, energy conversion, and energy storage devices. Graphene-based nanocomposites are under an intense spotlight amongst researchers. A large amount of graphene is required for preparation of such samples. Lately, graphene-based materials have been the target for fundamental life science investigations. Despite graphene being a much sought-after raw material, the drawbacks in the preparation of graphene are that it is a challenge amongst researchers to produce this material in a scalable quantity and that there is a concern about its safety. Thus, a simple and efficient method for the preparation of graphene oxide (GO) is greatly desired to address these problems. In this work, one-pot chemical oxidation of graphite was carried out at room temperature for the preparation of large-area GO with ~100% conversion. This high-conversion preparation of large-area GO was achieved using a simplified Hummer’s method from large graphite flakes (an average flake size of 500 μm). It was found that a high degree of oxidation of graphite could be realized by stirring graphite in a mixture of acids and potassium permanganate...

Spatially Explicit Large Area Biomass Estimation: Three Approaches Using Forest Inventory and Remotely Sensed Imagery in a GIS

Wulder, Michael A.; White, Joanne C.; Fournier, Richard A.; Luther, Joan E.; Magnussen, Steen
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 24/01/2008 EN
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45.87%
Forest inventory data often provide the required base data to enable the large area mapping of biomass over a range of scales. However, spatially explicit estimates of above-ground biomass (AGB) over large areas may be limited by the spatial extent of the forest inventory relative to the area of interest (i.e., inventories not spatially exhaustive), or by the omission of inventory attributes required for biomass estimation. These spatial and attributional gaps in the forest inventory may result in an underestimation of large area AGB. The continuous nature and synoptic coverage of remotely sensed data have led to their increased application for AGB estimation over large areas, although the use of these data remains challenging in complex forest environments. In this paper, we present an approach to generating spatially explicit estimates of large area AGB by integrating AGB estimates from multiple data sources; 1. using a lookup table of conversion factors applied to a non-spatially exhaustive forest inventory dataset (R2 = 0.64; RMSE = 16.95 t/ha), 2. applying a lookup table to unique combinations of land cover and vegetation density outputs derived from remotely sensed data (R2 = 0.52; RMSE = 19.97 t/ha), and 3. hybrid mapping by augmenting forest inventory AGB estimates with remotely sensed AGB estimates where there are spatial or attributional gaps in the forest inventory data. Over our 714...

NAVIS-An UGV Indoor Positioning System Using Laser Scan Matching for Large-Area Real-Time Applications

Tang, Jian.; Chen, Yuwei.; Jaakkola, Anttoni.; Liu, Jinbing.; Hyyppä, Juha.; Hyyppä, Hannu.
Fonte: MDPI Publicador: MDPI
Tipo: Artigo de Revista Científica
Publicado em 04/07/2014 EN
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45.79%
Laser scan matching with grid-based maps is a promising tool for real-time indoor positioning of mobile Unmanned Ground Vehicles (UGVs). While there are critical implementation problems, such as the ability to estimate the position by sensing the unknown indoor environment with sufficient accuracy and low enough latency for stable vehicle control, further development work is necessary. Unfortunately, most of the existing methods employ heuristics for quick positioning in which numerous accumulated errors easily lead to loss of positioning accuracy. This severely restricts its applications in large areas and over lengthy periods of time. This paper introduces an efficient real-time mobile UGV indoor positioning system for large-area applications using laser scan matching with an improved probabilistically-motivated Maximum Likelihood Estimation (IMLE) algorithm, which is based on a multi-resolution patch-divided grid likelihood map. Compared with traditional methods, the improvements embodied in IMLE include: (a) Iterative Closed Point (ICP) preprocessing, which adaptively decreases the search scope; (b) a totally brute search matching method on multi-resolution map layers, based on the likelihood value between current laser scan and the grid map within refined search scope...

Large area tactile sensors for smart surfaces with low power consumption

Andújar Morgado, Juan Miguel
Fonte: Universidade Carlos III de Madrid Publicador: Universidade Carlos III de Madrid
Tipo: info:eu-repo/semantics/bachelorThesis; info:eu-repo/semantics/masterThesis Formato: application/pdf; application/pdf
ENG
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The tactile sensors are able to detect the force applied by an object or person. Commonly, they are arrayed in matrix of force, where they act as variable resistance. The principal applications of tactile sensor are: robotic hands (to detect different slip, contact and texture), medical devices (to detect for instance breast cancer), artificial skin for robots (they can interact with the environment) This report presents results from a selection of tactile sensors that have been designed and fabricated for a large area conception. The sensor is based on piezoresistivity of the material, where it only need a conductive material and electrodes to be able to detect contact. In this work, there have been presented the results from sensor made using printed circuit board. This report provides details regarding the design of the hardware, selecting the best shape of the electrode. Furthermore, we present a novel method to measure the tactel, this novel method is based on measuring the tactels independently, inspired in the common digital camera CMOS, where is shown that the new readout circuit works perfectly and the consumption is lower than other philosophies presented in this report. __________________________________________________________________________________________________________________________; Los sensores táctiles son empleados en muchos campos actualmente...

Ultrahigh Performance C60 Nanorod Large Area Flexible Photoconductor Devices via Ultralow Organic and Inorganic Photodoping

Saran, Rinku; Stolojan, Vlad; Curry, Richard J.
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 23/05/2014 EN
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One dimensional single-crystal nanorods of C60 possess unique optoelectronic properties including high electron mobility, high photosensitivity and an excellent electron accepting nature. In addition, their rapid large scale synthesis at room temperature makes these organic semiconducting nanorods highly attractive for advanced optoelectronic device applications. Here, we report low-cost large-area flexible photoconductor devices fabricated using C60 nanorods. We demonstrate that the photosensitivity of the C60 nanorods can be enhanced ~400-fold via an ultralow photodoping mechanism. The photodoped devices offer broadband UV-vis-NIR spectral tuneability, exhibit a detectivitiy >109 Jones, an external quantum efficiency of ~100%, a linear dynamic range of 80 dB, a rise time 60 µs and the ability to measure ac signals up to ~250 kHz. These figures of merit combined are among the highest reported for one dimensional organic and inorganic large-area planar photoconductors and are competitive with commercially available inorganic photoconductors and photoconductive cells. With the additional processing benefits providing compatibility with large-area flexible platforms, these devices represent significant advances and make C60 nanorods a promising candidate for advanced photodetector technologies.

Macroscopic and high-throughput printing of aligned nanostructured polymer semiconductors for MHz large-area electronics

Bucella, Sadir G.; Luzio, Alessandro; Gann, Eliot; Thomsen, Lars; McNeill, Christopher R.; Pace, Giuseppina; Perinot, Andrea; Chen, Zhihua; Facchetti, Antonio; Caironi, Mario
Fonte: Nature Pub. Group Publicador: Nature Pub. Group
Tipo: Artigo de Revista Científica
Publicado em 25/09/2015 EN
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45.79%
High-mobility semiconducting polymers offer the opportunity to develop flexible and large-area electronics for several applications, including wearable, portable and distributed sensors, monitoring and actuating devices. An enabler of this technology is a scalable printing process achieving uniform electrical performances over large area. As opposed to the deposition of highly crystalline films, orientational alignment of polymer chains, albeit commonly achieved by non-scalable/slow bulk alignment schemes, is a more robust approach towards large-area electronics. By combining pre-aggregating solvents for formulating the semiconductor and by adopting a room temperature wired bar-coating technique, here we demonstrate the fast deposition of submonolayers and nanostructured films of a model electron-transporting polymer. Our approach enables directional self-assembling of polymer chains exhibiting large transport anisotropy and a mobility up to 6.4 cm2 V−1 s−1, allowing very simple device architectures to operate at 3.3 MHz. Thus, the proposed deposition strategy is exceptionally promising for mass manufacturing of high-performance polymer circuits.

Large Area Roller Embossing of Multilayered Ceramic Green Composites

Shan, X.; Soh, Y. C.; Shi, C. W. P.; Tay, C. K.; Lu, C. W.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 07/05/2008
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45.81%
In this paper, we will report our achievements in developing large area patterning of multilayered ceramic green composites using roller embossing. The aim of our research is to pattern large area ceramic green composites using a modified roller laminating apparatus, which is compatible with screen printing machines, for integration of embossing and screen printing. The instrumentation of our roller embossing apparatus, as shown in Figure1, consists of roller 1 and rollers 2. Roller 1 is heated up to the desired embossing temperature ; roller 2 is, however, kept at room temperature. The mould is a nickel template manufactured by plating nickel-based micro patterns (height : 50 $\mu$m) on a nickel film (thickness : 70 $\mu$m) ; the substrate for the roller embossing is a multilayered Heraeus Heralock HL 2000 ceramic green composite. Comparing with the conventional simultaneous embossing, the advantages of roller embossing include : (1) low embossing force ; (2) easiness of demoulding ; (3) localized area in contact with heater ; and etc. We have demonstrated the capability of large area roller embossing with a panel size of 150mmx 150mm on the mentioned substrate. We have explored and confirmed the impact of parameters (feed speed, temperature of roller and applied pressure) to the pattern quality of roller embossing. Furthermore...

A Large Area Timing RPC

Blanco, A.; Ferreira-Marques, R.; Finck, Ch.; Fonte, P.; Gobbi, A.; Policarpo, A.; Rozas, M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 26/03/2001
Relevância na Pesquisa
45.81%
A large area Resistive Plate Chamber (RPC) with a total active surface of 160x10 cm2 was built and tested. The surface was segmented in two 5 cm wide strips readout on both ends with custom, very high frequency, front end electronics. A timing resolution between 50 and 75 ps sigma with an efficiency for Minimum Ionizing Particles (MIPs) larger than 95% was attained over the whole active area, in addition with a position resolution along the strips of 1.2 cm. Despite the large active area per electronic channel, the observed timing resolution is remarkably close to the one previously obtained (50 ps sigma) with much smaller chambers of about 10 cm2 area. These results open perspectives of extending the application of timing RPCs to large area arrays exposed to moderate particle multiplicities, where the low cost, good time resolution, insensitivity to the magnetic field and compact mechanics may be attractive when compared with the standard scintillator-based Time-of-Flight (TOF) technology.; Comment: 22 pages, 10 figures (submitted to Nucl. Instr. and Meth.)

The Chandra Large Area Synoptic X-ray Survey (CLASXS) of the Lockman Hole-Northwest: The X-ray Catalog

Yang, Y.; Mushotzky, R. F.; Steffen, A. T.; Barger, A. J.; Cowie, L. L.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 03/09/2004
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45.82%
We present the X-ray catalog and basic results from our Chandra Large Area Synoptic X-ray Survey (CLASXS) of the Lockman Hole-Northwest field. Our 9 ACIS-I fields cover a contiguous solid angle of ~0.4 sq. deg. and reach fluxes of 5E-16 cgs (0.4-2 keV) and 3E-15 cgs (2-8keV). Our survey bridges the gap between ultradeep pencil-beam surveys, such as the Chandra Deep Fields (CDFs), and shallower, large area surveys, allowing a better probe of the X-ray sources that contribute most of the 2-10 keV cosmic X-ray background (CXB). We find a total of 525 X-ray point sources and 4 extended sources. At ~10E-14 cgs 2-8 keV, our number counts are significantly higher than those of several non-contiguous, large area surveys. On the other hand, the integrated flux from the CLASXS field, combined with ASCA and Chandra ultradeep surveys, is consistent with results from other large area surveys, within the variance of the CXB. Spectral evolution is seen in the hardening of the sources at fluxes below 1E-14 cgs Above 4E1-14 cgs(0.4-8 keV), ~60 of the sources are variable. Four extended sources in CLASXS is consistent with the previously measured LogN-LogS of galaxy clusters. We report the discovery of a gravitational lensing arc associated with one of these sources. (Abridged); Comment: 67 pages...

A Large Area Detector proposed for the Large Observatory for X-ray Timing (LOFT)

Zane, S.; Walton, D.; Kennedy, T.; Feroci, M.; Herder, J. -W. Den; Ahangarianabhari, M.; Argan, A.; Azzarello, P.; Baldazzi, G.; Barret, D.; Bertuccio, G.; Bodini, P.; Bozzo, E.; Cadoux, F.; Cais, P.; Campana, R.; Coker, J.; Cros, A.; Del Monte, E.; De Ro
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 07/09/2012
Relevância na Pesquisa
45.84%
The Large Observatory for X-ray Timing (LOFT) is one of the four candidate ESA M3 missions considered for launch in the 2022 time-frame. It is specifically designed to perform fast X-ray timing and probe the status of the matter near black holes and neutron stars. The LOFT scientific payload is composed of a Large Area Detector (LAD) and a Wide Field Monitor (WFM). The LAD is a 10 m2-class pointed instrument with 20 times the collecting area of the best past timing missions (such as RXTE) over the 2-30 keV range, which holds the capability to revolutionize studies of X-ray variability down to the millisecond time scales. Its ground-breaking characteristic is a low mass per unit surface, enabling an effective area of ~10 m^2 (@10 keV) at a reasonable weight. The development of such large but light experiment, with low mass and power per unit area, is now made possible by the recent advancements in the field of large-area silicon detectors - able to time tag an X-ray photon with an accuracy <10 {\mu}s and an energy resolution of ~260 eV at 6 keV - and capillary-plate X-ray collimators. In this paper, we will summarize the characteristics of the LAD instrument and give an overview of its capabilities.; Comment: Proceedings of SPIE, Vo. 8443...

Progress on large area GEMs

Pinto, Serge Duarte; Villa, Marco; Alfonsi, Matteo; Brock, Ian; Croci, Gabriele; David, Eric; de Oliveira, Rui; Ropelewski, Leszek; van Stenis, Miranda
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
45.81%
In 2008, a triple GEM detector prototype with an area of ~2000 cm2 has been constructed, based on foils of 66*66 cm. GEMs of such dimensions had not been made before, and innovations to the existing technology were introduced to build this detector. This paper discusses these innovations and presents further work on large area GEM development. A single-mask technique overcomes the cumbersome practice of alignment of two masks, which limits the achievable lateral size. The holes obtained with this technique are conical, and have a so-called rim, a small insulating clearance around the hole in the substrate. Further refinements of this technique allow greater control over the shape of holes and the size of rims. Also, an improvement in homogeneity over large areas is expected. Simulation studies have been done to examine the effect of hole shape on the behavior of GEMs. Such studies can help understanding how to use new enhancements of the technique to optimize performance. Many potential applications for large area GEMs foresee large production volumes. Production issues have been studied, and single-mask GEMs turn out to be much more suitable for large scale production than standard GEMs.; Comment: Contribution to the MPGD'09 conference...

Gamma ray Large Area Space Telescope (GLAST) Balloon Flight Engineering Model: Overview

Thompson, D. J.; Godfrey, G.; Williams, S.; Grove, J. E.; Lovellette, M.; Mizuno, T.; Sadrozinski, H. F. -W.; Collaboration, GLAST Large Area Telescope
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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65.78%
The Gamma Ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) is a pair-production high-energy (>20 MeV) gamma-ray telescope being built by an international partnership of astrophysicists and particle physicists for a satellite launch in 2006, designed to study a wide variety of high-energy astrophysical phenomena. As part of the development effort, the collaboration has built a Balloon Flight Engineering Model (BFEM) for flight on a high-altitude scientific balloon. The BFEM is approximately the size of one of the 16 GLAST-LAT towers and contains all the components of the full instrument: plastic scintillator anticoincidence system (ACD), high-Z foil/Si strip pair-conversion tracker (TKR), CsI hodoscopic calorimeter (CAL), triggering and data acquisition electronics (DAQ), commanding system, power distribution, telemetry, real-time data display, and ground data processing system. The principal goal of the balloon flight was to demonstrate the performance of this instrument configuration under conditions similar to those expected in orbit. Results from a balloon flight from Palestine, Texas, on August 4, 2001, show that the BFEM successfully obtained gamma-ray data in this high-background environment.; Comment: To be published in IEEE Transactions on Nuclear Science...

Deep Australia telescope large area survey radio observations of the European large area ISO survey S1/Spitzer wide-area infrared extragalactic field

Middelberg, Enno; Norris, Ray P.; Cornwell, Tim J.; Voronkov, Maxim A.; Siana, Brian D.; Boyle, Brian J.; Ciliegi, Paolo; Jackson, Carole A.; Huynh, Minh T.; Berta, Stefano; Rubele, Stefano; Lonsdale, Carol J.; Ivison, Rob J.; Smail, Ian
Fonte: American Astronomical Society Publicador: American Astronomical Society
Tipo: Article; PeerReviewed Formato: application/pdf; application/pdf
Publicado em /04/2008
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45.79%
We have conducted sensitive (1 σ < 30 μJy) 1.4 GHz radio observations with the Australia Telescope Compact Array of a field largely coincident with infrared observations of the Spitzer Wide-Area Extragalactic Survey. The field is centered on the European Large Area ISO Survey S1 region and has a total area of 3.9°. We describe the observations and calibration, source extraction, and cross-matching to infrared sources. Two catalogs are presented: one of the radio components found in the image and another of radio sources with counterparts in the infrared and extracted from the literature. 1366 radio components were grouped into 1276 sources, 1183 of which were matched to infrared sources. We discover 31 radio sources with no infrared counterpart at all, adding to the class of Infrared-Faint Radio Sources.

Large-area dry bean yield prediction modeling in Mexico

Medina-García,Guillermo; Baez-González,Alma Delia; López-Hernández,Jesús; Ruíz-Corral,José Ariel; Tinoco-Alfaro,Carlos Alberto; Kiniry,James R.
Fonte: Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias Publicador: Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2010 EN
Relevância na Pesquisa
55.74%
Given the importance of dry bean in Mexico and the need of know their production before the harvest, for the authorities of the agricultural sector, in order to define support to producers according to the expected harvest volume. The aim of this study was to develop an empirical model to estimate the yield of dry bean at the regional level prior to the harvest. An empirical dry bean (Phaseolus vulgaris L.) yield model that incorporates data on climate, leaf area index and yield components was developed for Zacatecas state, the major bean-producing area of Mexico, with 2005 data from 54 sampling sites planted with Negro San Luis, Flor de Mayo and Flor de Junio varieties of dry bean. Precipitation, leaf area index, number of pods per plant, grains per pod and plant, weight of 100 grains, plant density and grain yield data were obtained, and correlation and multiple regression analyses were made using 2005 data and the Statistical Analysis System (SAS) program. The model was validated with 2006 and 2007 data from 53 and 59 farmers' sites, respectively, in Zacatecas. Additionally, it was tested with 2006 and 2007 data from 34 and 36 sites, respectively, in the adjoining state of Durango, whose bean varieties and climatic, farmland, and crop management conditions are similar to those of Zacatecas. The results were highly significant (p<0.0001...

Large area P-I-N image sensitive devices deposited on plastic substrates

Vieira,M; Louro,P; Fernandes,M; Schwarz,R
Fonte: Sociedad Mexicana de Física Publicador: Sociedad Mexicana de Física
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2006 EN
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65.72%
Large area p-i-n image sensors deposited on plastic substrates were produced at low temperatures (110 °C) by PE-CVD and compared with similar sensors deposited on glass substrates. The same sensing element structure ZnO:Al/p(SiC:H)/i(Si:H)/n(SiC:H)/Al was used for both devices. In this work, the efforts are focused mainly on the optimization of the output characteristics of the sensor when fabricated on plastic substrates. The role of the sensor configuration and readout parameters on the image acquisition process is analyzed. The opticaltoelectrical transfer characteristics show a reasonable quantum efficiency under a red light pattern, broad spectral response, and reciprocity between light and image signal. First results show that the sensors deposited on a flexible substrate present smaller light to dark sensitivity than those deposited on glass. In both, the non-ohmic behavior of the transparent conductive oxide front contact blocks the carrier collection and leads to a surprising linear dependence of the image signal with the applied voltage.