Photoluminescence of GaAs/AlGaAs quantum wells

In this thesis is studied the influence of uniaxial deformation of GaAs/AlGaAs quantum well structures to photoluminescence. Uniaxial deformation was applied along [110] and polarization ratio of photoluminescence at T = 77 K and 300 K was measured. Also the physical origin of photoluminescence lines in spectrum was determined and the energy band splitting value between states of heavy and light holes was estimated. It was found that the dependencies of polarization ratio on uniaxial deformation for bulk GaAs and GaAs/AlGaAs are different. Two observed lines in photoluminescence spectrum are induced by free electron recombination to energy sublevels of valence band corresponding to heavy and light holes. Those sublevels are splited due to the combination of size quantization and external pressure. The quantum splitting energy value was estimated. Also was shown a method, which allows to determine the energy splitting value of sublevels at room temperature and at comparatively low uniaxial deformation, when the other method for determining of the splitting becomes impossible.

Integroitujen laitekaappien tuotannon tehostaminen elektroniikkateollisuudessa

Laitekaappien integrointi koostuu moduulien sekä kaapeleiden liittämisestä mallikohtaisiksi kokonaisuuksiksi. Tämä kokoonpanoprosessi on tilausohjautuva ja tehdään mallikohtaisesti yksittäiskokoonpanona. Mallien integrointityön vaikeus ja kokoonpanoaika vaihtelevat voimakkaasti. Tämä yhdistettynä työvoiman vaihtuvuuteen luo haastavan ympäristön kehittää tuotantoa sekä laadun että kapasiteetin näkökulmasta. Työssä on selvitetty voidaanko näitä kehittää jakamalla tuotantoprosessi pienempiin vaiheisiin, jotka ovat helpompi tasapainottaa ja oppia. Kokoomalinjan soveltaminen tilausohjautuvaan tuotantoon vaatii perinteiseen tahdistettuun kokoomalinjaan nähden suurempien poikkeavuuksien sallimista. Toisistaan merkittävästi poikkeavien työaikojen ja laajan mallivariaation vuoksi linjaa ei pystytä hallitsemaan niin järjestelmällisesti kuin tasapituisilla työvaiheilla. Tehokkaan tuotannon aikaansaaminen tällaiselle linjalle vaatii mahdollisuutta työjärjestyksen suunnitteluun ja sen simulointiin. Tässä työssä on pyritty arvioimaan simuloinnin avulla kokoomalinjan toimivuutta stokastisen kysynnän vallitessa. Malli on luotu hyväksikäyttäen tuotteiden valmistusaikoja, jotka on jaettu mallikohtaisesti kaikkiin mahdollisiin työtehtäviin. Nämä tehtävät on pyritty tasapainottamaan eri työpisteiden tehtäviksi. Tasapainotuksen tavoitteena on ollut minimoida tuotteiden työtehtävien keston voimakasta hajontaa, jota mallien kysynnän satunnaisuus voimistaa. Simulointien perusteella on luotu yksinkertaistettu sääntö työjärjestyksen muodostamiselle. Mallinnuksessa on pyritty maksimoimaan tuotannon tehokkuus minimoiden sekä keskeneräisen tuotannon määrää että läpimenoaikaa. Tehokkaimman vaihtoehdon löydyttyä on arvioitu kokoomalinjan soveltuvuutta laitekaappien integrointiin.

NMR in Crystals and Powders of Topazes with Different Colours

The present work is a part of the large project with purpose to investigate microstructure and electronic structure of natural topazes using NMR method. To reach this task we determined the relative contents of fluorine and hydrogen in crystals blue, colorless, wine and wine irradiated topazes. Then we determined the electric field gradients in site of aluminium atoms by NMR method, calculated EFG using ab initio method, and measured relaxation time dependence on heating temperature for blue, colorless, Swiss blue and sky blue topazes. Nuclear magnetic resonance (NMR) is an effective method to investigate the local structure in the crystal. The NMR study of the single crystal gives detailed information especially about the local crystal structure. As a result of this work we have received practical data, which is possible to use in future for making personal dosimetry and for preparation of mullite, which is widely used in traditional and advanced ceramic materials.

Thylakoid Protein Phosphorylation in Regulation of Photosynthesis

Once the seed has germinated, the plant is forced to face all the environmental changes in its habitat. In order to survive, plants have evolved a number of different acclimation systems. The primary reaction behind plant growth and development is photosynthesis. Photosynthesis captures solar energy and converts it into chemical form. Photosynthesis in turn functions under the control of environmental cues, but is also affected by the growth, development, and metabolic state of a plant. The availability of solar energy fluctuates continuously, requiring non-stop adjustment of photosynthetic efficiency in order to maintain the balance between photosynthesis and the requirements and restrictions of plant metabolism. Tight regulation is required, not only to provide sufficient energy supply but also to prevent the damage caused by excess energy. The very first reaction of photosynthesis is splitting of water into the form of oxygen, hydrogen, and electrons. This most fundamental reaction of life is run by photosystem II (PSII), and the energy required for the reaction is collected by the light harvesting complex II (LHCII). Several proteins of the PSII-LHCII complex are reversibly phosphorylated according to the energy balance between photosynthesis and metabolism. Thylakoid protein phosphorylation has been under extensive investigation for over 30 years, yet the physiological role of phosphorylation remains elusive. Recently, the kinases behind the phosphorylation of PSII-LHCII proteins (STN7 and STN8) were identified and the knockout mutants of these kinases became available, providing powerful tools to elucidate the physiological role of PSII-LHCII phosphorylation. In my work I have used the stn7 and stn8 mutants in order to clarify the role of PSII-LHCII phosphorylation in regulation and protection of the photosynthetic machinery according to environmental cues. I show that STN7- dependent PSII-LHCII protein phosphorylation is required to balance the excitation energy distribution between PSII and PSI especially under low light intensities when the excitation energy transfer from LHC to PSII and PSI is efficient. This mechanism differs from traditional light quality-induced “state 1” – “state 2” transition and ensures fluent electron transfer from PSII to PSI under low light, yet having highest physiological relevance under fluctuating light intensity. STN8-dependent phosphorylation of PSII proteins, in turn, is required for fluent turn-over of photodamaged PSII complexes and has the highest importance upon prolonged exposure of the photosynthetic apparatus to excess light.

Mental Health of Expatriates in Finnish Enterprises in Brazil

Expatriation has become increasingly common due to the global trade expansion. Many large companies base their production facilities in far-flung countries, where experts are sent from their own countries to launch the operations. Working in a foreign environment demands from so-called expatriates considerable adaptability. This study aimed to investigate if following expatriation mental health difficulties were experienced by the employees themselves or their family members. This study investigated by a questionnaire and interviews how expatriate employees in Finnish companies operating in different regions of Brazil and their families adjusted. Investigated employees were required to be at least 6 months in expatriation. Data were collected in Brazil during their stay at least 3 months after the arrival. The survey covered 121 expatriate employees, that operated in 17 different companies, from which 71 employees from 10 different companies responded to the questionnaire. All the employees from the two largest enterprises and their spouses were invited to focus groups; in total 43 persons (22 employees and 21 employees’ spouses) participated in a group or individual interviews. No significant mental health difficulties were found among the expatriate employees. Only a tenth of the expatriate employees reported strain. The experience of strain symptoms was found to be related to long working days, intense working rhythm and lack of friends. Work satisfaction seemed to be an important mediator in the coping process. While abroad, the expatriate employees were highly recognized for their work. Due to the immature organization of work they could often use their creative capacities to improve the work flow. The opportunity to see the effects of their own contribution with their own eyes to the development of the enterprise made them feel good. The association between the expatriate employees’ adjustment and that of their spouses’ was evident. The spouses’ situation was markedly different than that of the expatriate employees’ themselves. Expatriation changed the family members’ previous division of tasks considerably. The expatriate spouses had to change their roles more than the expatriate employees themselves; since most of them were highly educated women, who were leaded through an identity crisis due to at least temporary renunciation of own work and career.

Comparison Structure Analysis

This study presents an automatic, computer-aided analytical method called Comparison Structure Analysis (CSA), which can be applied to different dimensions of music. The aim of CSA is first and foremost practical: to produce dynamic and understandable representations of musical properties by evaluating the prevalence of a chosen musical data structure through a musical piece. Such a comparison structure may refer to a mathematical vector, a set, a matrix or another type of data structure and even a combination of data structures. CSA depends on an abstract systematic segmentation that allows for a statistical or mathematical survey of the data. To choose a comparison structure is to tune the apparatus to be sensitive to an exclusive set of musical properties. CSA settles somewhere between traditional music analysis and computer aided music information retrieval (MIR). Theoretically defined musical entities, such as pitch-class sets, set-classes and particular rhythm patterns are detected in compositions using pattern extraction and pattern comparison algorithms that are typical within the field of MIR. In principle, the idea of comparison structure analysis can be applied to any time-series type data and, in the music analytical context, to polyphonic as well as homophonic music. Tonal trends, set-class similarities, invertible counterpoints, voice-leading similarities, short-term modulations, rhythmic similarities and multiparametric changes in musical texture were studied. Since CSA allows for a highly accurate classification of compositions, its methods may be applicable to symbolic music information retrieval as well. The strength of CSA relies especially on the possibility to make comparisons between the observations concerning different musical parameters and to combine it with statistical and perhaps other music analytical methods. The results of CSA are dependent on the competence of the similarity measure. New similarity measures for tonal stability, rhythmic and set-class similarity measurements were proposed. The most advanced results were attained by employing the automated function generation – comparable with the so-called genetic programming – to search for an optimal model for set-class similarity measurements. However, the results of CSA seem to agree strongly, independent of the type of similarity function employed in the analysis.

A generalized 1D particle transport method for convection diffusion reaction model

This work is devoted to the development of numerical method to deal with convection diffusion dominated problem with reaction term, non - stiff chemical reaction and stiff chemical reaction. The technique is based on the unifying Eulerian - Lagrangian schemes (particle transport method) under the framework of operator splitting method. In the computational domain, the particle set is assigned to solve the convection reaction subproblem along the characteristic curves created by convective velocity. At each time step, convection, diffusion and reaction terms are solved separately by assuming that, each phenomenon occurs separately in a sequential fashion. Moreover, adaptivities and projection techniques are used to add particles in the regions of high gradients (steep fronts) and discontinuities and transfer a solution from particle set onto grid point respectively. The numerical results show that, the particle transport method has improved the solutions of CDR problems. Nevertheless, the method is time consumer when compared with other classical technique e.g., method of lines. Apart from this advantage, the particle transport method can be used to simulate problems that involve movingsteep/smooth fronts such as separation of two or more elements in the system.

The Vulnerable Brain and Very Preterm Infants - Findings from the PIPARI-Study

Preterm birth is a risk for normal brain development. Brain maturation that normally happens in the uterus is in very preterm infants a developmental challenge during their stay in a neonatal intensive care unit (NICU). Typical brain injuries of preterm infants include ischemic injuries, brain haemorrhages, ventricular dilatation (VD), and reduced brain volumes. Brain injury is a serious complication of prematurity leading to possible long term consequences for the neurodevelopment of the very low birth weight (VLBW) infant, such as cerebral palsy (CP), hearing impairments, vision problems, and delay in cognitive development.There is a need for further studies to ascertain the potential risk factors and their causal relationships to brain vulnerability, growth and development in the increasing number of surviving VLBW infants. This thesis consists of four studies evaluating the definitions, causes and consequences of brain lesions in VLBW(<1500g) or very low gestationalage (VLGA) (gestational age <32 gestational weeks) infants. We showed that the redistribution of fetal blood flow is a risk factor for smaller brain volumes at term. In addition,we showed that brain lesions related to prematurity are not associated with increased spontaneous crying behaviour or circadian rhythm development in infancy. However, the preterm infants began to fuss more often and were held more than term infants at five months of age. Furthermore, we showed that VD is associated with brain lesions and smaller brain volumes. Therefore, brain magneticresonance imaging can be recommended for infants with VD. VD together with other brain pathology is a risk factor for the onset of developmental impairments in VLBW/VLGA infants at two years of age.

Maantieteen rytmit

Kirjallisuusarvostelu

Musikalisk lärandemiljö : planerade musikaktiviteter med småbarn i daghem

A musically stimulating nvironment is of great significance when considering the opportunities for development and learning that are offered to children in day nurseries. Moreover, the quality of musical activities also has great significance for the musical development of growing children. Young children are always striving to create meaning and understanding; they influence and are influenced by the context in which they are situated. The purpose of this study is to investigate the planned music activities in the musical learning environment of seven toddler’s groups in day nurseries, based on four different aspects: the texts of children’s songs, the melodies of children’s songs, the basic elements of music and the use of instrumentation. The data has been gathered by video observation of the planned music activities. The age of the children studied ranged from 11 months to 3 years and 11 months, and on average there were 13 children in each group. The study involved a total of just over 90 children and nine educators. The methodological approaches are hermeneutic as well as videographic, and they are applied to the analysis as required. The approaches are well suited to an understanding of the planned music activities where the individual’s communications and actions are studied. The results of the study show that educators impart a cultural heritage to the children in the form of old traditional songs, but they also act as intermediaries for newer children's songs. They focus on actively on the text content of the children’s songs in their interaction with the children, but do not address the meaning of the text. Furthermore, while the educators use music sessions for the children to develop, among other things, an understanding of language and social skills, they do not use the sessions to develop the children’s musical skills. The educators could, to a much greater extent than they now do, direct the children's attention to the basic elements of music, and conduct meta-cognitive dialogues with the children. They use a large repertoire of children's songs, which are, however, often too demanding for the children’s voices to cope with. In addition, the educators do not plan, in any significant way, activities for the toddlers in order to help them develop the accuracy of their vocal tones. With regard to the use of instruments, the educators focus, in their interaction with the children, is placed on both the usage of the instruments and knowledge about the instruments. Regarding the use of instruments the study shows that the children’s musical expression takes place in an environment that includes both melody and rhythm instruments. It is clear that children are actively interested in the constructed instrument environment, because for long periods of time they independently play and experiment with instruments.

Growth, magnetic and transport properties of InSb and II-IV-As2 semiconductors doped with manganese

This thesis is devoted to growth and investigations of Mn-doped InSb and II-IV-As2 semiconductors, including Cd1-xZnxGeAs2:Mn, ZnSiAs2:Mn bulk crystals, ZnSiAs2:Mn/Si heterostructures. Bulk crystals were grown by direct melting of starting components followed by fast cooling. Mn-doped ZnSiAs2/Si heterostructures were grown by vacuum-thermal deposition of ZnAs2 and Mn layers on Si substrates followed by annealing. The compositional and structural properties of samples were investigated by different methods. The samples consist of micro- and nano- sizes clusters of an additional ferromagnetic Mn-X phases (X = Sb or As). Influence of magnetic precipitations on magnetic and electrical properties of the investigated materials was examined. With relatively high Mn concentration the main contribution to magnetization of samples is by MnSb or MnAs clusters. These clusters are responsible for high temperature behavior of magnetization and relatively high Curie temperature: up to 350 K for Mn-doped II-IV-As2 and about 600 K for InMnSb. The low-field magnetic properties of Mn-doped II-IV-As2 semiconductors and ZnSiAs2:Mn/Si heterostructures are connected to the nanosize MnAs particles. Also influence of nanosized MnSb clusters on low-field magnetic properties of InMnSb have been observed. The contribution of paramagnetic phase to magnetization rises at low temperatures or in samples with low Mn concentration. Source of this contribution is not only isolated Mn ions, but also small complexes, mainly dimmers and trimmers formed by Mn ions, substituting cation positions in crystal lattice. Resistivity, magnetoresistance and Hall resistivity properties in bulk Mn-doped II-IV-As2 and InSb crystals was analyzed. The interaction between delocalized holes and 3d shells of the Mn ions together with giant Zeeman splitting near the cluster interface are respond for negative magnetoresistance. Additionally to high temperature critical pointthe low-temperature ferromagnetic transition was observed Anomalous Hall effect was observed in Mn doped samples and analyzed for InMnSb. It was found that MnX clusters influence significantly on magnetic scattering of carriers.

Sukupolvenvaihdoksen toteuttaminen henkilöyhtiössä

Tutkielma on kvalitatiivinen tutkimus, jossa pääpaino perustuu kirjallisuus- ja oikeustapaustutkimukseen. Tutkielman tavoitteena on selvittää henkilöyhtiön sukupolvenvaihdoksen toteuttamisen vaihtoehdot sekä henkilöyhtiön yhtiöosuuksien luovutuksena että yhtiömuodon muutoksella, jolloin henkilöyhtiö muutetaan ensin osakeyhtiöksi ja sen jälkeen osakeyhtiö voi jakautua. Perheyrityksen sukupolvenvaihdoksen ja siihen liittyvien veroseuraamusten optimointi edellyttää suunnitelmallista prosessia, missä otetaan huomioon eri toteutusvaihtoehtojen verotuksellinen kohtelu sekä luopujien että jatkajien kannalta. Perheen sisällä tapahtuvat sukupolvenvaihdokset tapahtuvat useimmiten lahjana tai lahjanluonteisena kauppana, jolloin perintö- ja lahjaverotus on tarpeen ottaa huomioon jo suunnitteluvaiheessa. Yritysvarallisuuden arvostaminen perintö- ja lahjaverotuksessa sekä sukupolvenvaihdoksen yhteydessä saatavat verohuojennukset ja niiden huomioon ottaminen ovat tärkeitä tekijöitä. Tutkielman case- yrityksessä luopujien ja jatkajien tarpeet huomioiden yhtiömuodon muutos ja jakautuminen voitiin todeta kannattavimmaksi vaihtoehdoksi.