D. K. W. (pikku ihme) polkupyörämoottorin montteerausohje

10 x 20 cm

D. K. W. (pikku ihme) polkupyörämoottorin montteerausohje

11 x 20 cm

K. H. Täten on meillä kunnia ilmoittaa

14 x 22 cm

Gargoyle Mobiloil hinnasto no K 16

kuv., 10 x 18 cm

Mobiloil prislista no K 16

kuv., 10 x 18 cm

S.A.K:n pikakartta

kuv., 21 x 29 cm

Den nya Star-Rugby-automobilen

14 x 10 cm

Uusi Star-Rugby-auto

14 x 10 cm

"Star" 4-personers Touring

kuv., 21 x 14 cm

"Star" 4-hengen Touring

kuv., 21 x 14 cm

K-junalla sedulaan : luokkataustaiset makuluokittelut Helsingin yöelämässä

Teema: Luokka.

T&k-toiminnan suorituskyvyn johtaminen: kontekstin vaikutus mittaamiseen pk-yrityksissä

Tutkimuksen päätavoitteena oli ymmärtää, kuinka konteksti vaikuttaa t&k-toiminnan suorituskyvyn mittaamiseen pk-yrityksissä. Tutkimus kartoitti ja kuvaili kontekstin vaikutusta mallilla, joka jaottelee mittaamisen sisältöön, kontekstiin ja prosessiin. Kontekstin vaikutusta sisältöön ja prosessiin tutkittiin sekä suoraan että välillisesti mittaamisen tavoitteen kautta. Tutkimuksessa käytettiin case survey-tutkimusmenetelmää, jossa yhdistyy survey-tutkimuksen ja tapaustutkimuksen strategiat. Empiirisenä aineistona käytettiin olemassa olevia tapaustutkimuksia, joiden laadulliset havainnot muunnettiin systemaattisesti määrällisiksi muuttujiksi koodausjärjestelmällä. Muuttujien yhteyksien ristiintaulukoinnit analysoitiin tilastollisesti merkitsevien riippuvuuksien tunnistamiseksi ja laajempaa joukkoa koskevien päätelmien johtamiseksi. Tulokset olivat yhteneväisiä aiemman tutkimustiedon kanssa, mikä osoittaa kontekstin vaikutuksen t&k-toiminnan suorituskyvyn mittaamiseen olevan samankaltainen pk-yrityksissä kuin suuremmissakin yrityksissä. Empiirisinä yleistyksinä tunnistettiin uusia riippuvuuksia kontekstin ja sisällön sekä kontekstin ja prosessin välillä. Yleistykset suositellaan testattavaksi hypoteeseina jatkotutkimuksessa.

Kelvin Probe Force Microscopy (KPFM) characterization of lanthanum lutetium oxide high-k dielectric thin films

Lanthanum lutetium oxide (LaLuO3) thin films were investigated considering their perspective application for industrial microelectronics. Scanning probe microscopy (SPM) techniques permitted to visualize the surface topography and study the electric properties. This work compared both the material properties (charge behavior for samples of 6 nm and 25 nm width) and the applied SPM modes. Particularly, Kelvin probe force microscopy (KPFM) was applied to characterize local potential difference with high lateral resolution. Measurements showed the difference in morphology, chargeability and charge dissipation time for both samples. The polarity effect was detected for this material for the first time. Lateral spreading of the charged spots indicate the diffusive mechanism to be predominant in charge dissipation. This allowed to estimate the diffusion coefficient and mobility. Using simple electrostatic model it was found that charge is partly leaking into the interface oxide layer.

Modeling and Parameter Estimation of Double-Star Permanent Magnet Synchronous Machines

The power rating of wind turbines is constantly increasing; however, keeping the voltage rating at the low-voltage level results in high kilo-ampere currents. An alternative for increasing the power levels without raising the voltage level is provided by multiphase machines. Multiphase machines are used for instance in ship propulsion systems, aerospace applications, electric vehicles, and in other high-power applications including wind energy conversion systems. A machine model in an appropriate reference frame is required in order to design an efficient control for the electric drive. Modeling of multiphase machines poses a challenge because of the mutual couplings between the phases. Mutual couplings degrade the drive performance unless they are properly considered. In certain multiphase machines there is also a problem of high current harmonics, which are easily generated because of the small current path impedance of the harmonic components. However, multiphase machines provide special characteristics compared with the three-phase counterparts: Multiphase machines have a better fault tolerance, and are thus more robust. In addition, the controlled power can be divided among more inverter legs by increasing the number of phases. Moreover, the torque pulsation can be decreased and the harmonic frequency of the torque ripple increased by an appropriate multiphase configuration. By increasing the number of phases it is also possible to obtain more torque per RMS ampere for the same volume, and thus, increase the power density. In this doctoral thesis, a decoupled d–q model of double-star permanent-magnet (PM) synchronous machines is derived based on the inductance matrix diagonalization. The double-star machine is a special type of multiphase machines. Its armature consists of two three-phase winding sets, which are commonly displaced by 30 electrical degrees. In this study, the displacement angle between the sets is considered a parameter. The diagonalization of the inductance matrix results in a simplified model structure, in which the mutual couplings between the reference frames are eliminated. Moreover, the current harmonics are mapped into a reference frame, in which they can be easily controlled. The work also presents methods to determine the machine inductances by a finite-element analysis and by voltage-source inverters on-site. The derived model is validated by experimental results obtained with an example double-star interior PM (IPM) synchronous machine having the sets displaced by 30 electrical degrees. The derived transformation, and consequently, the decoupled d–q machine model, are shown to model the behavior of an actual machine with an acceptable accuracy. Thus, the proposed model is suitable to be used for the model-based control design of electric drives consisting of double-star IPM synchronous machines.