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41.
Antti?Laakso Mihail?Dumitrescu Jukka?Viheri?l? Jarkko?Telkk?l? Juha?Tommila Kimmo?Haring Tomi?Leinonen Sanna?Ranta Markus?Pessa 《Optical and Quantum Electronics》2009,41(1):11-16
The paper presents a simulation-based analysis of laterally-corrugated ridge-waveguide distributed feedback semiconductor
lasers emitting at 980 nm. The simulations were performed using software developed in-house and the PICS3D software package
from Crosslight Software Inc. The effects of the corrugation geometry, phase-shift section, and mirror reflectivities on single
longitudinal mode operation are discussed. The lasers, designed along the guidelines derived from the simulation results,
were fabricated by using molecular beam epitaxy for wafer growth and low-cost nano-imprint lithography. They exhibited stable
single-mode operation with up to 50 dB side-mode suppression ratio. 相似文献
42.
Milena Stepien Jarkko J. SaarinenHannu Teisala Mikko TuominenMikko Aromaa Jurkka KuusipaloJyrki M. Mäkelä Martti Toivakka 《Applied Surface Science》2011,257(6):1911-1917
Liquid flame spray process (LFS) was used for depositing TiOx and SiOx nanoparticles on paperboard to control wetting properties of the surface. By the LFS process it is possible to create either superhydrophobic or superhydrophilic surfaces. Changes in the wettability are related to structural properties of the surface, which were characterized using scanning electron microscope (SEM) and atomic force microscope (AFM). The surface properties can be ascribed as a correlation between wetting properties of the paperboard and the surface texture created by nanoparticles. Surfaces can be produced inline in a one step roll-to-roll process without need for additional modifications. Furthermore, functional surfaces with adjustable hydrophilicity or hydrophobicity can be fabricated simply by choosing appropriate liquid precursors. 相似文献
43.
Jarkko J. Saarinen Dimitar Valtakari Janne Haapanen Turkka Salminen Jyrki M. Mäkelä Jun Uozumi 《Optical Review》2014,21(3):339-344
Surface-enhanced Raman scattering (SERS) active substrates were made via liquid flame spray deposition and inkjet printing of silver nanoparticles. Both processes are suitable for cost-effective fabrication of large-area SERS substrates. Crystal violet (CV) solutions were used as target molecules and in both samples the detection limit was approximately 10 nM. In addition, sintering temperature of the inkjet printed silver nanoparticles was found to have a large effect on the SERS activity with the higher curing temperature of 200 °C resulting in contamination layer on silver and cancelation of the SERS signal. This layer was characterized using an X-ray photoelectron spectroscopy (XPS). 相似文献
44.
Anu J Airaksinen Jarkko LipsonenMarkku Ahlgren Pirjo VainiotaloKim A Bergström Reino LaatikainenJouko Vepsäläinen 《Tetrahedron》2003,59(3):377-383
Reduction of 6/7-carboethoxy-3-phenyltrop-3-en-2-ones with H2/Pd/C and NaBH4 was studied in order to find a stereoselective route to the corresponding 3-phenyltropan-2-ones and 2α/2β-hydroxy-3-phenyltropanes. The 6/7-exo-carboethoxy-3-phenyltrop-3-en-2-ones were selectively reduced by Pd/C to 3β-phenyltropan-2-ones and 2α-hydroxy-3β-phenyltropanes. The corresponding 2β-hydroxy-3β-phenyl analogues were synthesized using NaBH4, with a yield of 40%. Reduction of 6-endo-carboethoxy-3-phenyltrop-3-en-2-one yielded several products. The corresponding 7-endo-substituted analogue was selectively reduced with both Pd/C and NaBH4 to 7-endo-carboethoxy-3β-phenyltropin-2-one. Analysis of stereochemically important 1H NMR spectroscopy parameters was performed for all the products and used for conformational analysis in solution. X-ray analysis was performed for selected compounds. 相似文献
45.
Jarkko Rapala Kirsti ErkomaaJaana Kukkonen Kaarina SivonenKirsti Lahti 《Analytica chimica acta》2002,466(2):213-231
A colorimetric protein phosphatase inhibition assay (PPI assay), a commercial enzyme-linked immunosorbent assay (ELISA) test and different HPLC methods using UV detection were compared for the detection of cyanobacterial hepatotoxins, microcystins (MCYST) and nodularin. The suitability of the methods to detect different toxin variants was evaluated by using pure toxins and laboratory cultures as well as water and bloom samples of toxic cyanobacteria. The emphasis of the study was on the analysis of polar demethyl microcystin variants that are common in nature but for which there exist no commercial standards. The IC50 values of MCYST-LR for the PPI assay and the ELISA test were 2.2-2.5 and 0.26-0.38 μg l−1, respectively. The most important factors that decreased toxin recovery in sample treatment were the use of C18 cartridges and polypropylene containers. Good recoveries of toxins were obtained by using hydrophilic-lipophilic balanced (Oasis HLB, Waters) cartridges for concentrating the samples. The results obtained with the PPI assay, the ELISA test and HPLC correlated quantitatively well with the exception of [d-Asp3] microcystins. Concentrations of [d-Asp3]MCYST-RR measured with the PPI assay were only 5% of those obtained by the ELISA test and HPLC. Concentrations of hydrophobic microcystin variants were lower when analysed with ELISA than with the other methods. The World Health Organisation (WHO) has set a guideline value of 1 μg l−1 for the world-wide most common microcystin variant, MCYST-LR in drinking water. Since the quantitative ranges of the PPI assay and the ELISA test are within microcystin concentrations in natural waters, and both tests are easy to perform, they show potential for routine use in the screening and monitoring of microcystins from drinking water supplies and from recreational waters. 相似文献
46.
Kalle Salminen Jian-Hui Fang Jarkko Etula Niklas Wester Jarkko Eskola Sakari Kulmala Jian-Jun Sun 《Electroanalysis》2023,35(3):e202200227
Electrochemistry of hot electrons in fully aqueous solutions at tetrahedral amorphous carbon thin film electrodes is discussed. The generation of these highly reducing chemical species was confirmed by normal pulse voltammetry and several electrochemiluminescent systems. Electron transfer into pre-existing solvent cavities was observed at approximately −2.65 V vs. Ag/AgCl (sat.). Electrogenerated hot electrons were utilized as chemiluminescent mediators in heterogeneous sandwich immunoassay of Serum Amyloid A. The calibration curve was linear over four orders of magnitude and the detection limit was 85 ng L−1 that demonstrates the efficiency of hot electron generation at this electrode material. 相似文献
47.
Lauri Järvinen Jarkko Albert Leiro Frej Bjondahl Claudio Carletti Olav Eklund 《Surface and interface analysis : SIA》2012,44(5):519-528
The dissolution of seven natural limestones and calcareous rocks in hydrochloric acid solution was examined to investigate their capability for wet flue gas desulphurisation. All samples were crushed, ground and sieved to a size‐fraction of 150–250 µm. Thereafter they were subjected to a dissolution experiment utilising stepwise titration with hydrochloric acid. The dissolution rates of three calcareous rocks were found to be controlled by reaction kinetics, while the limestones showed mass transfer control. The surface characterisation was implemented before and after dissolution experiments using X‐ray photoelectron spectroscopy and scanning electron microscopy. Additional characterisation was carried out with X‐ray diffraction, X‐ray fluorescence and polarizing microscope. Initial reactivities have been shown to decrease in the order limestone, calcareous rock with high calcium concentration, calcareous rock with low calcium concentration. Coarse grain structure is proposed to decrease the initial reactivity. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
48.
49.
Hannu Teisala Mikko Tuominen Mikko Aromaa Milena Stepien Jyrki M. Mäkelä Jarkko J. Saarinen Martti Toivakka Jurkka Kuusipalo 《Colloid and polymer science》2013,291(2):447-455
Surface wetting is an important and relevant phenomenon in several different fields. Scientists have introduced a large number of applications where special surface wetting could be exploited. Here, we study wetting phenomena on high- and low-adhesive superhydrophobic liquid flame spray (LFS)-generated TiO2 coatings on paper and pigment-coated board substrates using water–ethanol solution as a probe liquid. Submicrometer-scale air gaps, which exist on superhydrophobic surfaces below the liquid droplets, were more stable with the ethanol increment than the larger-scale micrometric air gaps. With the droplet ethanol concentration of 15 wt%, static contact angle as high as 155?±?2° was measured on the LFS–TiO2-coated board. Transition from the low-adhesive wetting state to the high-adhesive state was demonstrated on the LFS–TiO2-coated paper. The LFS method enables efficient roll-to-roll production of surfaces with special wetting properties on economically viable board and paper substrate materials. 相似文献
50.
Jukka Hassinen Jussi Kauppila Jarkko Leiro Anni Määttänen Petri Ihalainen Jouko Peltonen Jukka Lukkari 《Analytical and bioanalytical chemistry》2013,405(11):3611-3617
The fabrication concept for a low-cost sensor device using reduced graphene oxide (rGO) as the sensing material on a porous paper substrate is presented. The sensors were characterized using conductivity and capacitance measurements, atomic force microscopy and X-ray photoelectron spectroscopy. The effects of different reducing agents, graphene oxide (GO) flake size and film thickness were studied. The sensor was sensitive to NO2, and devices based on a thin (10-nm) hydrazine-reduced GO layer had the best sensitivity, reaching a 70 % reduction in resistance after 10 min of exposure to 10 ppm NO2. The sensitivity was high enough for the detection of sub-parts per million levels of NO2. Desorption of gas molecules, i.e. the recovery of the sensor, could be accelerated by UV irradiation. The structure and preparation of the sensor are simple and up-scalable, allowing their fabrication in bulk quantities, and the fabrication concept can be applied to other materials, too. Figure
Low‐cost reduced graphene oxide based conductometric nitrogen dioxide sensitive sensor on paper 相似文献