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3篇 您的检索式:作者名="Daniel Haffa"
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1Efficient offline production of freestanding thin plastic foils for laser-driven ion sources显示文摘Modern chirped pulse amplification laser systems with continuously improving controllability and increasing power are about to reach intensities of up to 10^(22) W cm^(-2) and have proven their potential to accelerate ions out of plasma to several tens percent of the speed of light. For enabling application, one important step is to increase the repetition rate at which ion bunches are at the disposal. In particular, techniques used so far for thin foil target production can require several days of preparing reasonable amounts for a single campaign. In this paper we describe the reasonably droplet method which we have tested and improved so that the emerging foils with thicknesses of a few nanometres up to micrometre can be used as targets for laser ion acceleration. Their quality and performance can compete with so far employed techniques thereby enabling the production of hundreds of targets per day.Sebastian Seuferling Matthias Alexander Otto Haug Peter Hilz Daniel Haffa Christian Kreuzer Jorg Schreiber 2017High Power Laser Science and Engineering2017,5,2:1
2An automated, 0.5 Hz nano-foil target positioning system for intense laser plasma experiments显示文摘We report on a target system supporting automated positioning of nano-targets with a precision resolution of 4 μm in three dimensions. It relies on a confocal distance sensor and a microscope. The system has been commissioned to position nanometer targets with 1 Hz repetition rate. Integrating our prototype into the table-top ATLAS 300 TW-laser system at the Laboratory for Extreme Photonics in Garching, we demonstrate the operation of a 0.5 Hz laser-driven proton source with a shot-to-shot variation of the maximum energy about 27% for a level of confidence of 0.95. The reason of laser shooting experiments operated at 0.5 Hz rather than 1 Hz is because the synchronization between the nano-foil target positioning system and the laser trigger needs to improve.Ying Gao Jianhui Bin Daniel Haffa Christian Kreuzer Jens Hartmann Martin Speicher Florian H.Lindner Tobias M.Ostermayr Peter Hilz Thomas F.Rsch Sebastian Lehrack Franz Englbrecht Sebastian Seuferling Max Gilljohann Hao Ding Wenjun Ma Katia Parodi Jorg Schreiber 2017High Power Laser Science and Engineering2017,5,2:1
3Improving immunization capacity in Ethiopia through continuous quality improvement interventions:a prospective quasi-experimental study显示文摘Background:Strong scientific evidence is needed to support low-income countries in building effective and sustainable immunization programs and proactively engaging in global vaccine development and implementation initiatives.This study aimed to implement and evaluate the effectiveness of system-wide continuous quality improvement(CQI)interventions to improve national immunization programme performance in Ethiopia.Methods:The study used a prospective,quasi-experimental design with an interrupted time-series analysis to collect data from 781 government health sectors(556 healthcare facilities,196 district health offices,and 29 zonal health departments)selected from developing and emerging regions in Ethiopia.Procedures included baseline quality assessment of immunization programme and services using structured checklists;immunization systems strengthening using onsite technical support,training,and supportive supervision interventions in a Plan-Do-Check-Act cycle over 12 months;and collection and analysis of data at baseline and at the 6th and 12th month of interventions using statistical process control and the t-test.Outcome measures were the coverage of the vaccines pentavalent 3,measles,Bacillus Calmette-Guérin vaccine(BCG),Pneumococcal Conjugate Vaccine(PCV),as well as full vaccination status;while process measures were changes in human resources,planning,service delivery,logistics and supply,documentation,coordination and collaboration,and monitoring and evaluation.Analysis and interpretation of data adhered to SQUIRE 2.0 guidelines.Results:Prior to the interventions,vaccination coverage was low and all seven process indicators had an aggregate score of below 50%,with significant differences in performance at healthcare facility level between developing and emerging regions(P=0.0001).Following the interventions,vaccination coverage improved significantly from 63.6%at baseline to 79.3%for pentavalent(P=0.0001),62.5 to 72.8%for measles(P=0.009),62.4 to 73.5%for BCG(P=0.0001),65.3 to 81.0%for PCV(P=0.02),and insignificantly from 56.2 to 74.2%for full vaccination.All seven process indicators scored above 75%in all regions,with no significant differences found in performance between developing and emerging regions.Conclusions:The CQI interventions improved immunization capacity and vaccination coverage in Ethiopia,where the unstable transmission patterns and intensity of infectious diseases necessitate for a state of readiness of the health system at all times.The approach was found to empower zone,district,and facility-level health sectors to exercise accountability and share ownership of immunization outcomes.While universal approaches can improve routine immunization,local innovative interventions that target local problems and dynamics are also necessary to achieve optimal coverage.Tsegahun Manyazewal Alemayehu Mekonnen Tesfa Demelew Semegnew Mengestu Yusuf Abdu Dereje Mammo Workeabeba Abebe Belay Haffa Daniel Zenebe Bogale Worku Amir Aman Setegn Tigabu 2018Infectious Diseases of Poverty2018,7,1:1
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