124 research outputs found

    Simulation of High Conversion Efficiency and Open-circuit Voltages Of {\alpha}-si/poly-silicon Solar Cell

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    The P+ {\alpha}-Si /N+ polycrystalline solar cell is molded using the AMPS-1D device simulator to explore the new high efficiency thin film poly-silicon solar cell. In order to analyze the characteristics of this device and the thickness of N+ poly-silicon, we consider the impurity concentration in the N+ poly-silicon layer and the work function of transparent conductive oxide (TCO) in front contact in the calculation. The thickness of N+ poly-silicon has little impact on the device when the thickness varies from 20 {\mu}m to 300 {\mu}m. The effects of impurity concentration in polycrystalline are analyzed. The conclusion is drawn that the open-circuit voltage (Voc) of P+ {\alpha}-Si /N+ polycrystalline solar cell is very high, reaching 752 mV, and the conversion efficiency reaches 9.44%. Therefore, based on the above optimum parameters the study on the device formed by P+ {\alpha}-Si/N+ poly-silicon is significant in exploring the high efficiency poly-silicon solar cell.Comment: 8 pages 6figures, 1 table

    Ultrathin 2 nm gold as ideal impedance-matched absorber for infrared light

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    Thermal detectors are a cornerstone of infrared (IR) and terahertz (THz) technology due to their broad spectral range. These detectors call for suitable broad spectral absorbers with minimalthermal mass. Often this is realized by plasmonic absorbers, which ensure a high absorptivity butonly for a narrow spectral band. Alternativly, a common approach is based on impedance-matching the sheet resistance of a thin metallic film to half the free-space impedance. Thereby, it is possible to achieve a wavelength-independent absorptivity of up to 50 %, depending on the dielectric properties of the underlying substrate. However, existing absorber films typicallyrequire a thickness of the order of tens of nanometers, such as titanium nitride (14 nm), whichcan significantly deteriorate the response of a thermal transducers. Here, we present the application of ultrathin gold (2 nm) on top of a 1.2 nm copper oxide seed layer as an effective IR absorber. An almost wavelength-independent and long-time stable absorptivity of 47(3) %, ranging from 2 μ\mum to 20 μ\mum, could be obtained and is further discussed. The presented gold thin-film represents analmost ideal impedance-matched IR absorber that allows a significant improvement of state-of-the-art thermal detector technology

    From salty to fresh—salinity processes in the Upper-ocean Regional Study-2 (SPURS-2) : diagnosing the physics of a rainfall-dominated salinity minimum

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    Author Posting. © The Oceanography Society, 2015. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 28, no. 1 (2015): 150-159, doi:10.5670/oceanog.2015.15.One of the notable features of the global ocean is that the salinity of the North Atlantic is about 1 psu higher than that of the North Pacific. This contrast is thought to be due to one of the large asymmetries in the global water cycle: the transport of water vapor by the trade winds across Central America and the lack of any comparable transport into the Atlantic from the Sahara Desert. Net evaporation serves to maintain high Atlantic salinities, and net precipitation lowers those in the Pacific. Because the effects on upper-ocean physics are markedly different in the evaporating and precipitating regimes, the next phase of research in the Salinity Processes in the Upper-ocean Regional Study (SPURS) must address a high rainfall region. It seemed especially appropriate to focus on the eastern tropical Pacific that is freshened by the water vapor carried from the Atlantic. In a sense, the SPURS-2 Pacific region will be looking at the downstream fate of the freshwater carried out of the SPURS-1 North Atlantic region. Rainfall tends to lower surface density and thus inhibit vertical mixing, leading to quite different physical structure and dynamics in the upper ocean. Here, we discuss the motivations for the location of SPURS-2 and the scientific questions we hope to address

    Mixing to monsoons: Air-sea interactions in the bay of Bengal

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    More than 1 billion people depend on rainfall from the South Asian monsoon for their livelihoods. Summertime monsoonal precipitation is highly variable on intraseasonal time scales, with alternating "active" and "break" periods. These intraseasonal oscillations in large-scale atmospheric convection and winds are closely tied to 1°C-2°C variations of sea surface temperature in the Bay of Bengal

    Super sites for advancing understanding of the oceanic and atmospheric boundary layers

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    © The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Clayson, C. A., Centurioni, L., Cronin, M. F., Edson, J., Gille, S., Muller-Karger, F., Parfitt, R., Riihimaki, L. D., Smith, S. R., Swart, S., Vandemark, D., Boas, A. B. V., Zappa, C. J., & Zhang, D. Super sites for advancing understanding of the oceanic and atmospheric boundary layers. Marine Technology Society Journal, 55(3), (2021): 144–145, https://doi.org/10.4031/MTSJ.55.3.11.Air‐sea interactions are critical to large-scale weather and climate predictions because of the ocean's ability to absorb excess atmospheric heat and carbon and regulate exchanges of momentum, water vapor, and other greenhouse gases. These exchanges are controlled by molecular, turbulent, and wave-driven processes in the atmospheric and oceanic boundary layers. Improved understanding and representation of these processes in models are key for increasing Earth system prediction skill, particularly for subseasonal to decadal time scales. Our understanding and ability to model these processes within this coupled system is presently inadequate due in large part to a lack of data: contemporaneous long-term observations from the top of the marine atmospheric boundary layer (MABL) to the base of the oceanic mixing layer. We propose the concept of “Super Sites” to provide multi-year suites of measurements at specific locations to simultaneously characterize physical and biogeochemical processes within the coupled boundary layers at high spatial and temporal resolution. Measurements will be made from floating platforms, buoys, towers, and autonomous vehicles, utilizing both in-situ and remote sensors. The engineering challenges and level of coordination, integration, and interoperability required to develop these coupled ocean‐atmosphere Super Sites place them in an “Ocean Shot” class.NOAA CVP TPOS, Understanding Processes Controlling Near-Surface Salinity in the Tropical Ocean Using Multiscale Coupled Modeling and Analysis, NA18OAR4310402 to CAC and JE. NSF Award PLR-1425989 and OPP-1936222, Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) to SG. NOAA, BOEM, ONR, NSF, NOPP, NASA Applied Sciences Office, Biodiversity & Ecological Forecasting Program; National Science Foundation (Co-PI J. Pearlman); OceanObs Research Coordination Network (OCE-1728913) to FM-K. NASA, SWOT program, Award # 80NSSC20K1136 to ABVB. NSF, Investigating the Air-Sea Energy Exchange in the presence of Surface Gravity Waves by Measurements of Turbulence Dissipation, Production and Transport, OCE 17-56839; NSF, A Multi-Spectral Thermal Infrared Imaging System for Air-Sea Interaction Research, OCE 20-23678; NSF, Investigating the Relationship Between Ocean Surface Gravity–Capillary Waves, Surface-Layer Hydrodynamics, and Air–Sea Momentum Flux, OCE 20-49579 to CJZ. Partially funded by NOAA/Climate Program Office and the Joint Institute for the Study of the Atmosphere and Ocean (JISAO) under NOAA Cooperative Agreement NA15OAR4320063 to DZ

    Autonomous and Lagrangian ocean observations for Atlantic tropical cyclone studies and forecasts

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    Author Posting. © The Oceanography Society, 2017. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 30, no. 2 (2017): 92–103, doi:10.5670/oceanog.2017.227.The tropical Atlantic basin is one of seven global regions where tropical cyclones (TCs) commonly originate, intensify, and affect highly populated coastal areas. Under appropriate atmospheric conditions, TC intensification can be linked to upper-ocean properties. Errors in Atlantic TC intensification forecasts have not been significantly reduced during the last 25 years. The combined use of in situ and satellite observations, particularly of temperature and salinity ahead of TCs, has the potential to improve the representation of the ocean, more accurately initialize hurricane intensity forecast models, and identify areas where TCs may intensify. However, a sustained in situ ocean observing system in the tropical North Atlantic Ocean and Caribbean Sea dedicated to measuring subsurface temperature, salinity, and density fields in support of TC intensity studies and forecasts has yet to be designed and implemented. Autonomous and Lagrangian platforms and sensors offer cost-effective opportunities to accomplish this objective. Here, we highlight recent efforts to use autonomous platforms and sensors, including surface drifters, profiling floats, underwater gliders, and dropsondes, to better understand air-sea processes during high-wind events, particularly those geared toward improving hurricane intensity forecasts. Real-time data availability is key for assimilation into numerical weather forecast models.The NOAA/AOML component of this work was originally funded by the Disaster Relief Appropriations Act of 2013, also known as the Sandy Supplemental, and is currently funded through NOAA research grant NA14OAR4830103 by AOML and CARICOOS, as well as NOAA’s Integrated Ocean Observing System (IOOS). The TEMPESTS component of this work is supported by NOAA through the Cooperative Institute for the North Atlantic Region (NA13OAR4830233) with additional analysis support from the WHOI Summer Student Fellowship Program, Nortek Student Equipment Grant, and the Rutgers University Teledyne Webb Graduate Student Fellowship Program. The drifter component of this work is funded through NOAA grant NA15OAR4320071(11.432) in support of the Global Drifter Program

    Global perspectives on observing ocean boundary current systems

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    Ocean boundary current systems are key components of the climate system, are home to highly productive ecosystems, and have numerous societal impacts. Establishment of a global network of boundary current observing systems is a critical part of ongoing development of the Global Ocean Observing System. The characteristics of boundary current systems are reviewed, focusing on scientific and societal motivations for sustained observing. Techniques currently used to observe boundary current systems are reviewed, followed by a census of the current state of boundary current observing systems globally. The next steps in the development of boundary current observing systems are considered, leading to several specific recommendations.Fil: Todd, Robert E.. Woods Hole Oceanographic Institution; Estados UnidosFil: Chavez, Francisco. Monterey Bay Aquarium Research Institute; Estados UnidosFil: Clayton, Sophie. Old Dominion University; Estados UnidosFil: Cravatte, Sophie E.. Centre National de la Recherche Scientifique. Institut de Recherche pour le Développement; Francia. Universite de Toulouse; FranciaFil: Goes, Marlos P.. University of Miami; Estados UnidosFil: Graco, Michelle I.. Instituto del Mar del Peru; PerúFil: Lin, Xiaopei. Ocean University of China; ChinaFil: Sprintall, Janet. University of California; Estados UnidosFil: Zilberman, Nathalie V.. University of California; Estados UnidosFil: Archer, Matthew. California Institute of Technology; Estados UnidosFil: Arístegui, Javier. Universidad de Las Palmas de Gran Canaria; EspañaFil: Balmaseda, Magdalena A.. European Centre for Medium-Range Weather Forecasts; Reino UnidoFil: Bane, John M.. University of North Carolina; Estados UnidosFil: Baringer, Molly O.. Atlantic Oceanographic and Meteorological Laboratory ; Estados UnidosFil: Barth, John A.. State University of Oregon; Estados UnidosFil: Beal, Lisa M.. University of Miami; Estados UnidosFil: Brandt, Peter. Geomar-Helmholtz Centre for Ocean Research Kiel; AlemaniaFil: Calil, Paulo H.. Universidade Federal do Rio Grande; BrasilFil: Campos, Edmo. Universidade de Sao Paulo; BrasilFil: Centurioni, Luca R.. University of California; Estados UnidosFil: Chidichimo, María Paz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; ArgentinaFil: Cirano, Mauro. Universidade Federal do Rio de Janeiro; BrasilFil: Cronin, Meghan F.. National Oceanic and Atmospheric Administration. Pacific Marine Environmental Laboratory; Estados UnidosFil: Curchitser, Enrique N.. Rutgers University; Estados UnidosFil: Davis, Russ E.. University of California; Estados UnidosFil: Dengler, Marcus. Geomar-Helmholtz Centre for Ocean Research Kiel; AlemaniaFil: DeYoung, Brad. Memorial University of Newfoundland; CanadáFil: Dong, Shenfu. University of Miami; Estados UnidosFil: Escribano, Ruben. Universidad de Concepción; ChileFil: Fassbender, Andrea J.. Monterey Bay Aquarium Research Institute; Estados Unido

    Prevalence of human papillomavirus cervical infection in an Italian asymptomatic population

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    BACKGROUND: In the last decade many studies have definitely shown that human papillomaviruses (HPVs) are the major cause of cervical carcinogenesis and, in the last few years, HPV testing has been proposed as a new and more powerful tool for cervical cancer screening. This issue is now receiving considerable attention in scientific and non scientific press and HPV testing could be considered the most important change in this field since the introduction of cervical cytology. This paper reports our prevalence data of HPV infection collected in the '90s, while a follow up of these patients is ongoing. METHODS: For this study we used polymerase chain reaction (PCR) to search HPV DNA sequences in cervical cell scrapings obtained from 503 asymptomatic women attending regular cervical cancer screening program in the city of Genova, Italy. All patients were also submitted to a self-administered, standardized, questionnaire regarding their life style and sexual activity. On the basis of the presence of HPV DNA sequences women were separated into two groups: "infected" and "non infected" and a statistical analysis of the factors potentially associated with the infection group membership was carried out. RESULTS: The infection rate was 15.9% and the most frequent viral type was HPV 16. CONCLUSION: Our HPV positivity rate (15.9%) was consistent to that reported by other studies on European populations

    Ocean observations in support of studies and forecasts of tropical and extratropical cyclones

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    © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Domingues, R., Kuwano-Yoshida, A., Chardon-Maldonado, P., Todd, R. E., Halliwell, G., Kim, H., Lin, I., Sato, K., Narazaki, T., Shay, L. K., Miles, T., Glenn, S., Zhang, J. A., Jayne, S. R., Centurioni, L., Le Henaff, M., Foltz, G. R., Bringas, F., Ali, M. M., DiMarco, S. F., Hosoda, S., Fukuoka, T., LaCour, B., Mehra, A., Sanabia, E. R., Gyakum, J. R., Dong, J., Knaff, J. A., & Goni, G. Ocean observations in support of studies and forecasts of tropical and extratropical cyclones. Frontiers in Marine Science, 6, (2019): 446, doi:10.3389/fmars.2019.00446.Over the past decade, measurements from the climate-oriented ocean observing system have been key to advancing the understanding of extreme weather events that originate and intensify over the ocean, such as tropical cyclones (TCs) and extratropical bomb cyclones (ECs). In order to foster further advancements to predict and better understand these extreme weather events, a need for a dedicated observing system component specifically to support studies and forecasts of TCs and ECs has been identified, but such a system has not yet been implemented. New technologies, pilot networks, targeted deployments of instruments, and state-of-the art coupled numerical models have enabled advances in research and forecast capabilities and illustrate a potential framework for future development. Here, applications and key results made possible by the different ocean observing efforts in support of studies and forecasts of TCs and ECs, as well as recent advances in observing technologies and strategies are reviewed. Then a vision and specific recommendations for the next decade are discussed.This study was supported by the National Oceanic and Atmospheric Administration and JSPS KAKENHI (Grant Numbers: JP17K19093, JP16K12591, and JP16H01846)

    A Comparison of the Conditioning Regimens BEAM and FEAM for Autologous Hematopoietic Stem Cell Transplantation in Lymphoma: An Observational Study on 1038 Patients From Fondazione Italiana Linfomi

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    Abstract Background Carmustine (BCNU)-Etoposide-Citarabine-Melphalan (BEAM) chemotherapy is the standard conditioning regimen for autologous stem cell transplantation (ASCT) in lymphomas. Owing to BCNU shortages, many centers switched to Fotemustine-substituted BEAM (FEAM), lacking proof of equivalence. Methods We conducted a retrospective cohort study in 18 Italian centers to compare safety and efficacy of BEAM and FEAM regimens for ASCT in lymphomas performed from 2008 to 2015. Results We enrolled 1038 patients (BEAM n=607, FEAM n=431), of which 27% had Hodgkin's lymphoma (HL), 14% indolent Non-Hodgkin's lymphoma (iNHL) and 59% aggressive NHL (aNHL). Baseline characteristics including age, sex, stage, B-symptoms, extranodal involvement, previous treatments, response before ASCT, overall conditioning intensity, were well balanced between BEAM and FEAM; notable exceptions were: ASCT year (median: BEAM=2011 vs FEAM=2013, p Conclusions BEAM and FEAM do not appear different in terms of survival and disease control. However, due to concerns of higher toxicity, Fotemustine substitution in BEAM does not seem justified, if not for easier supply
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