1.
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A new high-transmission inlet for the Caltech nano-RDMA for size distribution measurements of sub-3 nm ions at ambient concentrations
/ Franchin, Alessandro (Helsinki U.) ; Downard, Andy (Caltech, Pasadena (main)) ; Kangasluoma, Juha (Helsinki U.) ; Nieminen, Tuomo (Helsinki U. ; Helsinki Inst. of Phys. ; UEF, Kuopio) ; Lehtipalo, Katrianne (Helsinki U. ; Airmodus Ltd, Helsinki) ; Steiner, Gerhard (U. Vienna (main) ; Innsbruck U.) ; Manninen, Hanna E (Helsinki U.) ; Petäjä, Tuukka (Helsinki U.) ; Flagan, Richard C (Caltech, Pasadena (main)) ; Kulmala, Markku (Helsinki U.)
Reliable and reproducible measurements of atmospheric aerosol particle number size distributions below 10 nm require optimized classification instruments with high particle transmission efficiency. Almost all differential mobility analyzers (DMAs) have an unfavorable potential gradient at the outlet (e.g., long column, Vienna type) or at the inlet (nano-radial DMA), preventing them from achieving a good transmission efficiency for the smallest nanoparticles. [...]
2016 - 12 p.
- Published in : Atmos. Meas. Tech. 9 (2016) 2709-2720
Fulltext: PDF; External link: Fulltext
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2.
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Beam cooling using a gas-filled RFQ ion guide
/ Henry, S ; Martel-Bravo, I ; De Saint-Simon, M ; Jacotin, M ; Képinski, J F ; Lunney, M D
A radiofrequency quadrupole mass filter is being developed for use as a high-transmission beam cooler by operating it in buffer gas at high pressure. Such a device will increase the sensitivity of on-line experiments that make use of weakly produced radioactive ion beams. [...]
1999
In : Conference on Trapped Charged Particles and Related Fundamental Physics, Pacific Grove, CA, USA, 31 Aug - 4 Sep 1998, pp.120-4
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3.
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The effect of acid–base clustering and ions on the growth of atmospheric nano-particles
/ Lehtipalo, Katrianne (Helsinki U. ; PSI, Villigen) ; Rondo, Linda (Frankfurt U.) ; Kontkanen, Jenni (Helsinki U.) ; Schobesberger, Siegfried (Helsinki U. ; Washington U., Seattle) ; Jokinen, Tuija (Helsinki U.) ; Sarnela, Nina (Helsinki U.) ; Kürten, Andreas (Frankfurt U.) ; Ehrhart, Sebastian (Frankfurt U. ; CERN) ; Franchin, Alessandro (Helsinki U.) ; Nieminen, Tuomo (Helsinki U.) et al.
The growth of freshly formed aerosol particles can be the bottleneck in their survival to cloud condensation nuclei. It is therefore crucial to understand how particles grow in the atmosphere. [...]
2016
- Published in : Nature Commun. 7 (2016) 11594
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4.
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Molecular characterization of ultrafine particles using extractive electrospray time-of-flight mass spectrometry
/ Surdu, Mihnea (PSI, Villigen) ; Pospisilova, Veronika (PSI, Villigen) ; Xiao, Mao (PSI, Villigen) ; Wang, Mingyi (Carnegie Mellon U.) ; Mentler, Bernhard (Innsbruck U.) ; Simon, Mario (Frankfurt U., FIAS ; Frankfurt U.) ; Stolzenburg, Dominik (Vienna U., Dept. Math. ; Helsinki U.) ; Hoyle, Christopher R (PSI, Villigen ; Zurich, ETH) ; Bell, David M (PSI, Villigen) ; Lee, Chuan Ping (PSI, Villigen) et al.
Aerosol particles negatively affect human health while also having climatic relevance due to, for example, their ability to act as cloud condensation nuclei. Ultrafine particles (diameter D$_p$ < 100 nm) typically comprise the largest fraction of the total number concentration, however, their chemical characterization is difficult because of their low mass. [...]
2021 - 15 p.
- Published in : Environmental Science: Atmospheres 1 (2021) 434-448
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5.
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Performance of diethylene glycol-based particle counters in the sub-3 nm size range
/ Wimmer, D (Goethe U., Frankfurt (main)) ; Lehtipalo, K (Helsinki U. ; Airmodus, Helsinki) ; Franchin, A (Helsinki U.) ; Kangasluoma, J (Helsinki U.) ; Kreissl, F (Goethe U., Frankfurt (main)) ; Kürten, A (Goethe U., Frankfurt (main)) ; Kupc, A (U. Vienna (main)) ; Metzger, A (Goethe U., Frankfurt (main)) ; Mikkilä, J (Airmodus, Helsinki) ; Petäjä, J (Helsinki U.) et al.
When studying new particle formation, the uncertainty in determining the "true" nucleation rate is considerably reduced when using condensation particle counters (CPCs) capable of measuring concentrations of aerosol particles at sizes close to or even at the critical cluster size (1–2 nm). Recently, CPCs able to reliably detect particles below 2 nm in size and even close to 1 nm became available. [...]
2013
- Published in : Atmos. Meas. Tech. 6 (2013) 1793-1804
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6.
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Methods for determining particle size distribution and growth rates between 1 and 3 nm using the Particle Size Magnifier
/ Lehtipalo, Katrianne (Helsinki U. ; Airmodus, Helsinki) ; Leppä, Johannes (Finnish Meteorological Inst.) ; Kontkanen, Jenni (Helsinki U.) ; Kangasluoma, Juha (Helsinki U.) ; Franchin, Alessandro (Helsinki U.) ; Wimmer, Daniela (Helsinki U.) ; Schobesberger, Siegfried (Helsinki U.) ; Junninen, Heikki (Helsinki U.) ; Petäjä, Tuukka (Helsinki U.) ; Sipilä, Mikko (Helsinki U.) et al.
The most important parameters describing the atmospheric new particle formation process are the particle formation and growth rates. These together determine the amount of cloud condensation nuclei attributed to secondary particle formation. [...]
2014
- Published in : Boreal Env. Res.: 19 (suppl. B) (2014) , pp. 215-236
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7.
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Enhanced growth rate of atmospheric particles from sulfuric acid
/ Stolzenburg, Dominik (Vienna U. ; Helsinki U.) ; Simon, Mario (Frankfurt U.) ; Ranjithkumar, Ananth (Leeds U.) ; Kürten, Andreas (Frankfurt U.) ; Lehtipalo, Katrianne (Helsinki U. ; Finnish Meteorological Inst.) ; Gordon, Hamish (Leeds U.) ; Ehrhart, Sebastian (Mainz, Max Planck Inst.) ; Finkenzeller, Henning (U. Colorado, Boulder) ; Pichelstorfer, Lukas (Helsinki U.) ; Nieminen, Tuomo (Helsinki U.) et al.
In the present-day atmosphere, sulfuric acid is the
most important vapour for aerosol particle formation and initial growth. However, the growth rates of nanoparticles ( <
10 nm) from sulfuric acid remain poorly measured. [...]
2020 - 14 p.
- Published in : Atmos. Chem. Phys. 20 (2020) 7359-7372
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8.
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Molecular understanding of atmospheric particle formation from sulfuric acid and large oxidized organic molecules
/ Schobesberger, Siegfried (Helsinki U.) ; Junninen, Heikki (Helsinki U.) ; Bianchi, Federico (PSI, Villigen) ; Lönn, Gustaf (Helsinki U.) ; Ehn, Mikael (Helsinki U.) ; Lehtipalo, Katrianne (Helsinki U.) ; Dommen, Josef (PSI, Villigen) ; Ehrhart, Sebastian (Goethe U., Frankfurt (main)) ; Ortega, Ismael K (Helsinki U.) ; Franchin, Alessandro (Helsinki U.) et al.
Atmospheric aerosols formed by nucleation of vapors affect radiative forcing and therefore climate. However, the underlying mechanisms of nucleation remain unclear, particularly the involvement of organic compounds. [...]
2013
- Published in : Proc. Natl. Acad. Sci. U.S.A. 110 (2013) 17223-17228
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9.
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Modeling the thermodynamics and kinetics of sulfuric acid-dimethylamine-water nanoparticle growth in the CLOUD chamber
/ Ahlm, L (ACES, Stockholm University) ; Yli-Juuti, T (UEF, Kuopio) ; Schobesberger, S (Helsinki U. ; Washington U., Seattle) ; Praplan, A P (Helsinki U.) ; Kim, J (UEF, Kuopio) ; Tikkanen, O -P (UEF, Kuopio ; Helsinki U.) ; Lawler, M J (UC, Irvine) ; Smith, J N (UEF, Kuopio ; UC, Irvine) ; Tröstl, J (PSI, Villigen) ; Acosta Navarro, J C (ACES, Stockholm University) et al.
Dimethylamine (DMA) has a stabilizing effect on sulfuric acid (SA) clusters, and the SA and DMA molecules and clusters likely play important roles in both aerosol particle formation and growth in the atmosphere. We use the monodisperse particle growth model for acid-base chemistry in nanoparticle growth (MABNAG) together with direct and indirect observations from the CLOUD4 and CLOUD7 experiments in the cosmics leaving outdoor droplets (CLOUD) chamber at CERN to investigate the size and composition evolution of freshly formed particles consisting of SA, DMA, and water as they grow to 20 nm in dry diameter [...]
2016 - 16 p.
- Published in : Aerosol Sci. Technol. 50 (2016) 1017-1032
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10.
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Hygroscopicity of nanoparticles produced from homogeneous nucleation in the CLOUD experiments
/ Kim, J (UEF, Kuopio) ; Ahlm, L (Stockholm U.) ; Yli-Juuti, T (UEF, Kuopio) ; Lawler, M (UEF, Kuopio ; NCAR, Boulder) ; Keskinen, H (UEF, Kuopio) ; Tröstl, J (PSI, Villigen) ; Schobesberger, S (Helsinki U.) ; Duplissy, J (Helsinki U.) ; Amorim, A (Lisbon, CENTRA) ; Bianchi, F (PSI, Villigen ; Zurich, ETH) et al.
Sulfuric acid, amines and oxidized organics have been found to be important compounds in the nucleation and initial growth of atmospheric particles. Because of the challenges involved in determining the chemical composition of objects with very small mass, however, the properties of the freshly nucleated particles and the detailed pathways of their formation processes are still not clear. [...]
2016 - 12 p.
- Published in : Atmosph. Chem. Phys. 16 (2016) 293-304
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