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Hu, J. (author), Koleva, D.A. (author), Van Breugel, K. (author)
This paper reports the main results from the influence of the initially admixed nano-aggregates (0.5 g/l PEO113-b-PS70 micelles previously dissolved in demi-water) on microstructural alterations of the reinforced mortar subjected to chloride induced corrosion. The morphology of hydration/corrosion products at the steel/cement paste interface and...
journal article 2011
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Koleva, D.A. (author), Hu, J. (author), De Wit, J.H.W. (author), Boshkov, N. (author), Radeva, T. (author), Milkova, V. (author), Van Breugel, K. (author)
This work reports on the electrochemical performance of low-carbon steel electrodes in model alkaline solutions in the presence of 4.9.10-4 g/l hybrid aggregates i.e. cement extract, containing PDADMAC (poly (diallyl, dimethyl ammonium chloride) / PAA (Poly (acrylic acid)/ PDADMAC over a CaO core. The main objective was to determine if the...
journal article 2010
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Hu, J. (author), Koleva, D.A. (author), De Wit, J.H.W. (author), Petrov, P. (author), Van Breugel, K. (author)
This study presents the results from a preliminary investigation on the corrosion behavior of low carbon steel in cement extract (CE) in the presence of very low concentration polymeric nanoaggregates (PEO113-b-PS70 micelles). The steel electrodes were investigated in Cl--containing CE as corrosion medium, compared to chloride-free CE as a...
journal article 2010
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Hu, B.I. (author), Rush, D. (author), Van der Biezen, E. (author), Zheng, P. (author), Van Mullekom, M. (author), Schouten, S. (author), Sinninghe Damste, J.S. (author), Smolders, A.J.P. (author), Jetten, M.S.M. (author), Kartal, B. (author)
Anaerobic ammonium-oxidizing (anammox) bacteria have been recognized as an important sink for fixed nitrogen and are detected in many natural environments. However, their presence in terrestrial ecosystems has long been overlooked, and their contribution to the nitrogen cycling in natural and agricultural soils is currently unknown. Here we...
journal article 2010
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Ren, Y. (author), Hovenier, J.N. (author), Higgins, R. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Shi, S.C. (author), Bell, A. (author), Klein, B. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author)
A terahertz (THz) heterodyne spectrometer is demonstrated based on a quantum cascade laser (QCL) as a local oscillator (LO) and an NbN hot electron bolometer as a mixer, and it is used to measure high-resolution molecular spectral lines of methanol (CH3OH) between 2.913–2.918 THz. The spectral lines are taken from a gas cell containing methanol...
journal article 2010
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Koleva, D.A. (author), Hu, J. (author), Van Breugel, K. (author), Boshkov, N. (author), Radeva, T. (author), Milkova, V. (author)
journal article 2010
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Koleva, D.A. (author), Hu, J. (author), Van Breugel, K. (author), Boshkov, N. (author)
journal article 2010
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Hu, J. (author), Koleva, D.A. (author), Van Breugel, K. (author), Petrov, P. (author)
journal article 2010
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Abubakar, A. (author), Hu, W. (author), Habashy, T.M. (author), Van den Berg, P.M. (author)
We have applied the finite-difference contrast-source inversion (FDCSI) method to seismic full-waveform inversion problems. The FDCSI method is an iterative nonlinear inversion algorithm. However, unlike the nonlinear conjugate gradient method and the Gauss-Newton method, FDCSI does not solve any full forward problem explicitly in each iterative...
journal article 2009
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Khosropanah, P. (author), Baryshev, A. (author), Zhang, W. (author), Jellema, W. (author), Hovenier, J.N. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Paveliev, D.G. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author), Klein, B. (author), Hesler, J.L. (author)
We demonstrate the phase locking of a 2.7 THz metal–metal waveguide quantum cascade laser (QCL) to an external microwave signal. The reference is the 15th harmonic, generated by a semiconductor superlattice nonlinear device, of a signal at 182 GHz, which itself is generated by a multiplier chain (x12) from a microwave synthesizer at ~15 GHz....
journal article 2009
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De Lignie, M. (author), Hu, B.B. (author), Wijngaards, N. (author)
This research stems from the MOSAIC project, a part of the valorization and knowledge transfer effort of the Interactive Collaborative Information Systems (ICIS) research programme (http://www.icis.decis.nl/), supported by the Dutch Ministry of Economic Affairs, grant no.: BSIK03024. ICIS is hosted by the D-CIS Lab (http://www.decis.nl/), the...
conference paper 2008
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Abubakar, A. (author), Hu, W. (author), Van Den Berg, P.M. (author), Habashy, T.M. (author)
journal article 2008
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Koleva, D.A. (author), Hu, J. (author), Van Beek, K. (author), Van Breugel, K. (author), De Wit, J.H.W. (author)
patent 2007
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Koleva, D.A. (author), Hu, J. (author), Van Breugel, K. (author), De Wit, J.H.W. (author), Boshkov, N. (author)
An improved cathodic protection (CP), based on pulse regime was investigated in reinforced concrete, compared to conventional CP. Both regimes used CP current in the range of 2 to15 mA/m2. A voltage-to-current converter maintained the pulse current, the latter adjusted with duty cycle of 12% to 50 % and frequency of 500 Hz to 1 kHz. The...
journal article 2006
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Baryshev, A. (author), Hovenier, J.N. (author), Adam, A.J.L. (author), Kašalynas, I. (author), Gao, J.R. (author), Klaassen, T.O. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author)
We have studied the phase locking and spectral linewidth of an ? 2.7?THz quantum cascade laser by mixing its two lateral lasing modes. The beat signal at about 8?GHz is compared with a microwave reference by applying conventional phase lock loop circuitry with feedback to the laser bias current. Phase locking has been demonstrated, resulting in...
journal article 2006
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Adam, A.J.L. (author), Kašalynas, I. (author), Hovenier, J.N. (author), Klaassen, T.O. (author), Gao, J.R. (author), Orlova, E.E. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author)
The need to reach single-mode lasing and minimize at the same time the electrical dissipation of cryogenically operated terahertz quantum cascade lasers may result in small and subwavelength cavity dimensions. To assess the influence of such dimensions on the shape of the laser emission, we have measured the beam pattern of two metal-metal...
journal article 2006
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Orlova, E.E. (author), Hovenier, J.N. (author), Klaassen, T.O. (author), Kasalynas, I. (author), Adam, A.J.L. (author), Gao, J.R. (author), Klapwijk, T.M. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author)
journal article 2006
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Stroeven, P. (author), Hu, J. (author)
As a composite material, the performance of concrete materials can be expected to depend on the properties of the interfaces between its two major components, aggregate and cement paste. The microstructure at the interfacial transition zone (ITZ) is assumed to be different from the bulk material. In general, properties of conventional concrete...
journal article 2006
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Koleva, D.A. (author), Hu, J. (author), Van Breugel, K. (author), Boshkov, N. (author), De Wit, H. (author)
journal article 2005
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Gao, J.R. (author), Hovenier, J.N. (author), Yang, Z.Q. (author), Baselmans, J.J.A. (author), Baryshev, A. (author), Hajenius, M. (author), Klapwijk, T.M. (author), Adam, A.J.L. (author), Klaassen, T.O. (author), Williams, B.S. (author), Kumar, S. (author), Hu, Q. (author), Reno, J.L. (author)
We report the first demonstration of an all solid-state heterodyne receiver that can be used for high-resolution spectroscopy above 2?THz suitable for space-based observatories. The receiver uses a NbN superconducting hot-electron bolometer as mixer and a quantum cascade laser operating at 2.8?THz as local oscillator. We measure a double...
journal article 2005
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