TY - JOUR A1 - Helsper, Christoph A1 - Mölter, W. A1 - Haller, P. T1 - Representative Dilution of Aerosols by a Factor of 10,000 JF - Journal of Aerosol Science. 21 (1990), H. Suppl. 1 Y1 - 1990 SN - 0021-8502 SP - 637 EP - 640 ER - TY - JOUR A1 - Helsper, Christoph A1 - Wiedensohler, A. A1 - Weise, W. A1 - Lütkemeier, E. T1 - Determination of the Bipolar Charge Equilibrium in Pure Gases / Wiedensohler, A. ; Weise, W. ; Helsper, C. ; Lütkemeier, E. JF - Aerosols : formation and reactivity ; proceedings of the second International Aerosol Conference, 22-26 Sept. 1986, Berlin (West) / Gesellschaft für Aerosolforschung (GAeF) ; American Association for Aerosol Research (AAAR) Y1 - 1986 N1 - International Aerosol Conference ; (2, 1986, Berlin (West)) SP - 383 EP - 386 PB - Pergamon Press CY - Oxford [u.a.] ER - TY - JOUR A1 - Helsper, Christoph A1 - Lütkemeier, E. A1 - Wiedensohler, A. T1 - Charge Distribution by Unipolar Charging of Small Aerosol Particles / Lütkemeier, E. ; Helsper, C. ; Wiedensohler, A. JF - Aerosols : formation and reactivity ; proceedings of the second International Aerosol Conference, 22-26 Sept. 1986, Berlin (West) / Gesellschaft für Aerosolforschung (GAeF) ; American Association for Aerosol Research (AAAR) Y1 - 1986 N1 - International Aerosol Conference ; (2, 1986, Berlin (West)) SP - 474 EP - 478 PB - Pergamon Press CY - Oxford [u.a.] ER - TY - JOUR A1 - Helsper, Christoph T1 - Measurement Techniques For Ultrafine Particles JF - Ultrafine aerosols. Properties and behaviour. Proceedings of the 1. International Workshop on Ultrafine Aerosols of the Sonderforschungsbereich 209 'Stoff- und Energietransport in Aerosolen' -'Mass and energy transfer in aerosols'-, held at the Univ. of Duisburg on Sept. 29, 1986 Y1 - 1986 N1 - International Workshop on Ultrafine Aerosols ; (01) CY - Duisburg ER - TY - JOUR A1 - Helsper, Christoph A1 - Mölter, W. A1 - Willemer, W. T1 - Fast and Automated Testing of Filter Media / Mölter, W. ; Helsper, C. ; Willemer, W. JF - FILTECH Conference 1987 : Utrecht, Holland; September 23 - 25 1987 / org. by the Filtration Society , Vol. 1. Y1 - 1987 N1 - Filtech Conference ; (1987, Utrecht) SP - 106 EP - 112 PB - Filtration Society CY - Loughborough ER - TY - JOUR A1 - Helsper, Christoph T1 - Evaluation of Particle Size Distributions by Means of Particle Counters / Fißan, H. J. ; Helsper, C. JF - Proceedings of the First Workshop of Particulate Control : 16. - 17. March 1978, Kernforschung-sanlage Jülich GmbH / prepared by U.S. Environmental Protection Agency, Off. of Research and Development, Washington, D.C, 1979, Y1 - 1979 N1 - Workshop of Particulate Control ; (1, 1978, Jülich); Berichte der Kernforschungsanlage Jülich Conferences ; 28 PB - Zentralbibliothek d. Kernforschungsanlage Jülich [in Komm.] CY - Jülich ER - TY - JOUR A1 - Helsper, Christoph A1 - Fißan, H. J. T1 - Numerical Simulation Studies and Data Reduction for Size Classifying Measurement Techniques / Fißan, H. J.; Helsper, C. JF - Aerosols in science, medicine and technology : conference / Gesellschaft für Aerosolforschung 7. 1979. Y1 - 1979 SP - 199 EP - 205 ER - TY - JOUR A1 - Helsper, Christoph A1 - Fißan, H. J. T1 - Numerical Simulation Studies and Data Reduction for Size Classifying Measurement Techniques / Fißan, H. J.; Helsper, C. JF - Advances in Particle Sampling and Measurement: Proceedings, Daytona Beach, EPA 600/9 80 004, 1980 Y1 - 1980 N1 - Advances in Particle Sampling and Measurement ; (1979.10. : ; Daytona Beach/Fla.) PB - National Technical Information Service CY - Springfield, Va. ER - TY - JOUR A1 - Helsper, Christoph A1 - Fißan, H. J. A1 - Muggli, J. A1 - Scheidweiler, A. T1 - Particle Number Distributions of Aerosols from Test Fires JF - Journal of Aerosol Science. 11 (1980), H. 5-6 Y1 - 1980 SN - 0021-8502 SP - 439 EP - 446 ER - TY - JOUR A1 - Helsper, Christoph A1 - Fißan, H. J. T1 - Response Characteristic of a Polytec HC-15 Optical Particle Counter JF - Aerosols in science, medicine and technology : Physical and chemical properties of aerosols : Association for Aerosol Research: annual conference. 1980 : Gesellschaft für Aerosolforschung: annual conference. 1980 : Aerosols in science, medicine and technology : Physical and chemical properties of aerosols : Associa-tion for Aerosol Research: annual conference. 1980 : Gesellschaft für Aerosolforschung: annual conference. 1980 : Schmallenberg, 22.10.80 - 24.10.80 Y1 - 1981 N1 - Journal of aerosol science. Volume 0012 ; no 003 SP - 287 EP - 292 PB - Pergamon Pr. CY - Oxford ER -