As-deposited near-single crystalline high Tc and Jc superconducting thin films by a pulsed lased deposition process

As-deposited high Tc superconducting Y1Ba2Cu3O7−x films with zero resistance temperatures of similar, equals89 K and critical current densities about 0.7×106 A/cm2 at 77 K have been reproducibly fabricated at a substrate holder temperature at 650°C, using pulsed laser deposition, without post-annealing. One key to these results is the injection of gaseous oxygen into laser produced plume just in front of the target. In this way, the correct amount of oxygen is incorporated into the as-grown film so that post-deposition treatment becomes unnecessary. Axial ion channeling in these as-deposit high Tc superconducting films on (100) SrTiO3 and X-ray photoelectron spectroscopy (XPS) on the film surfaces were performed. Angular yield profile near the film surface for Ba, and the surface peak intensity were measured using 3 MeV He ions. For channeling normal to the substrate a minimum yield of 7%, compared to similar, equals3% for single crystals, was obtained. The results of ion channeling and XPS studies indicate that the as-deposited films have good crystallinity as well as toichiometry to within similar, equals1 nm of the film surface. The in-situ growth of such high Tc and Jc films is an important step in the use of the laser deposition technique to fabricate multilayer structures and the surface perfection is of importance in tunneling devices such as Josephson junctions.

Activation barrier for the alpha.-cleavage process in thiones

The Occurrence of the Norrish type I a-cleavage process in some thio compounds has been examined by using the MIND013 method and employing the configuration interaction. Results reveal that where the radiationless process is not efficient, thio compounds can undergo photodissociation into radicals in their lowest triplet and singlet excited states. The activation barriers in all these cases arise from an avoided crossing between two states of different symmetries. The calculations of activation barriers by the CNDO-CI and MINDO-CI procedures reveal that the MINDO-CI method leads to realistic values of the activation energies.

A building-up process in open-framework metal carboxylates that involves a progressive increase in dimensionality

Extensive research work has been carried out in the last few years on the synthesis and characterization of several families of open-framework materials, including aluminosilicates,[1] phosphates,[2] and carboxylates.[3] These studies have shown the occurrence of a variety of three dimensional (3D) architectures containing channels and other features.

Kotitalouden opetustilat osana kehittyvää oppimisympäristöä : asumistoiminnot ja opetussuunnitelma muutoksen määrittäjinä

Home Economics Classrooms as Part of Developing the Environment Housing Activities and Curriculums Defining Change --- The aim of the research project was to develop home economics classrooms to be flexible and versatile learning environments where household activities might be practiced according to the curriculum in different social networking situations. The research is based on the socio-cultural approach, where the functionality of the learning environment is studied specifically from an interactive learning viewpoint. The social framework is a natural starting point in home economics teaching because of the group work in classrooms. The social nature of learning thus becomes a significant part of the learning process. The study considers learning as experience based, holistic and context bound. The learning environment, i.e. home economics classrooms and the material tools there, plays a significant role in developing students skills to manage everyday life. --- The first research task was to analyze the historical development of household activities. The second research task was to develop and test criteria for functional home economics classrooms in planning both the learning environment and the students activities during lessons. The third research task was to evaluate how different professionals (commissioners, planners and teachers) use the criteria as a tool. The research consists of three parts. The first contains a historical analysis of how social changes have created tension between traditional household classrooms and new activities in homes. The historical analysis is based on housing research, regulations and instructions. For this purpose a new theoretical concept, the tension arch, was introduced. This helped in recognizing and solving problems in students activities and in developing innovations. The functionality criteria for home economics classrooms were developed based on this concept. These include technical (health, safety and technical factors), functional (ergonomic, ecological, aesthetic and economic factors) and behavioural (cooperation and interaction skills and communication technologies) criteria. --- The second part discusses how the criteria were used in renovating school buildings. Empirical data was collected from two separate schools where the activities during lessons were recorded both before and after classrooms were renovated. An analysis of both environments based on video recordings was conducted. The previously created criteria were made use of, and problematic points in functionality looked for particularly from a social interactive viewpoint. The results show that the criteria were used as a planning tool. The criteria facilitated layout and equipment solutions that support both curriculum and learning in home economics classrooms taking into consideration cooperation and interaction in the classroom. With the help of the criteria the home economics classrooms changed from closed and complicated space into integrated and open spaces where the flexibility and versatility of the learning environment was emphasized. The teacher became a facilitator and counselor instead a classroom controller. --- The third part analyses the discussions in planning meetings. These were recorded and an analysis was conducted of how the criteria and research results were used in the planning process of new home economics classrooms. The planning process was multivoiced, i.e. actors from different interest groups took part. All the previously created criteria (technical, functional and behavioural) emerged in the discussions and some of them were used as planning tools. Planning meetings turned into planning studios where boundaries between organizations were ignored and the physical learning environments were developed together with experts. The planning studios resulted in multivoiced planning which showed characteristics of collaborative and participating planning as well as producing common knowledge and shared expertise. --- KEY WORDS: physical learning environment, socio-cultural approach, tension arch, boundary crossing, collaborative planning.

Process of burnout: structure, antecedents, and consequences

The major changes that have been witnessed in today's workplaces are challenging the mental well-being of employed people. Stress and burnout are considered to be modern epidemics, and their importance to physical health and work ability has been acknowledged world-wide. The aim of the thesis was to study the concept of burnout as a process proceeding from its antecedents, through the development of the syndrome, and to its outcomes. Several work-related factors considered antecedents of burnout were studied in different occupational groups. The syndrome of burnout is seen as consisting of three dimensions - exhaustion, cynicism and lack of professional efficacy - and different alternatives for the sequential development of these dimensions were tested. Furthermore, several indicators of the severely detrimental health and work ability outcomes of burnout were investigated in a longitudinal study design. The research questions were as follows. 1) Is burnout, as measured with the Maslach Burnout Inventory - General Survey (MBI-GS), a three-dimensional construct and how invariant is the factorial structure across occupations (Finnish) and national samples (Finnish, Swedish and Dutch)? How persistent is exhaustion over time? 2) What is the sequential process of burnout? Is it similar across occupations? How do work stressors relate to the process? 3) How does burnout relate to severe health consequences as well as temporary and chronic work disability according to hospitalization periods, sick-leave episodes and receiving disability pensions? The data were collected between 1986 and 2005. The population of the study consisted of respondents to a company-wide questionnaire survey carried out in 1996-1997 (N=9705, response rate 63%). The participants comprised 6025 blue-collar workers and 3680 white-collar workers. The majority were men (N=7494) and the average age was 43.7 years. In addition, a sample from the population had responded to a questionnaire survey in 1988, which was combined with the 1996 data to form panel data on 713 respondents. The register-based data were collected between 1986 and 2005 from 1) the company's occupational health services' records for a sample of respondents from the 1996 questionnaire survey (sick-leave data), 2) hospitalization records from the Hospital discharge register, and 3) disability pension records from the Finnish Centre for Pensions. These data were combined person by person with the 1996 questionnaire survey data with the help of personal identification numbers which were saved with the study numbers by the researchers. The results showed that burnout consists of three separate but correlating symptoms: exhaustion, cynicism and lack of professional efficacy. As a syndrome, burnout was strongly related to job stressors at work, and seemed to develop from exhaustion through cynicism to lack of professional efficacy in a similar manner among white-collar and blue-collar employees. The results also showed that exhaustion persisted even after eight years of follow-up but did not predict cynicism or lack of professional efficacy after that amount of time. Nor were job stressors longitudinally related to burnout. Longitudinal results were obtained for the severe health-related consequences of burnout. The investigated outcomes represented different phases of health deterioration ranging from sick-leaves and hospitalization periods to receiving work disability pensions. The results showed that burnout syndrome, and its elements of exhaustion and cynicism, were related to future mental and cardiovascular disorders as indicated by hospitalization periods. Burnout was also related to future sick-leave periods due to mental, cardiovascular and musculoskeletal disorders. Of the separate elements, exhaustion was related to the same three categories of disorder, cynicism to mental, musculoskeletal and digestive disorders, and lack of professional efficacy to mental and musculoskeletal disorders. Burnout also predicted receiving disability pensions due to mental and musculoskeletal disorders among initially healthy subjects. Exhaustion was related to receiving disability pensions even when self-reported chronic illness was taken into account. The results suggest that burnout is a multidimensional, chronic, work-related syndrome, which may have serious consequences for health and work ability.

Synthesis of FeCu Nanopowder by Levitational Gas Condensation Process

Condensation from the vapor state is an important technique for the preparation of nanopowders. Levitational gas condensation is one such technique that has a unique ability of attaining steady state. Here, we present the results of applying this technique to an iron-copper alloy (96Fe-4Cu). A qualitative model of the process is proposed to understand the process and the characteristics of resultant powder. A phase diagram of the alloy system in the liquid-vapor region was calculated to help understand the course of condensation, especially partitioning and coring during processing. The phase diagram could not explain coring in view of the simultaneous occurrence of solidification and the fast homogenization through diffusion in the nanoparticles; however, it could predict the very low levels of copper observed in the levitated drop. The enrichment of copper observed near the surface of the powder was considered to be a manifestation of the lower surface energy of copper compared with that of iron. Heat transfer calculations indicated that most condensed particles can undergo solidification even when they are still in the proximity of the levitated drop. It helped us to predict the temperature and the cooling rate of the powder particles as they move away from the levitated drop. The particles formed by the process seem to be single domain, single crystals that are magnetic in nature. They, thus, can agglomerate by forming a chain-like structure, which manifests as a three-dimensional network enclosing a large unoccupied space, as noticed in scanning electron microscopy and transmission electron microscopy studies. This also explains the observed low packing density of the nanopowders.

Effect of sintering on optical, structural and photoluminescence properties of ZnO thin films prepared by sol-gel process

Zinc oxide (ZnO) thin films have been deposited on glass substrates via sol-gel technique using zinc acetate dihydrate as precursor by spin coating of the sol at 2000 rpm. Effects of annealing temperature on optical, structural and photo luminescence properties of the deposited ZnO films have been investigated. The phase transition from amorphous to polycrystalline hexagonal wurtzite structure was observed at an annealing temperature of 400 degrees C. An average transmittance of 87% in the visible region has been obtained at room temperature. The optical transmittance has slightly increased with increase of annealing temperature. The band gap energy was estimated by Tauc's method and found to be 3.22 eV at room temperature. The optical band gap energy has decreased with increasing annealing temperature. The photoluminescence (PL) intensity increased with annealing temperature up to 200 degrees C and decreased at 300 degrees C. (c) 2010 Elsevier B.V. All rights reserved.

Prediction of protein-protein interactions in dengue virus coat proteins guided by low resolution cryoEM structures

Background: Dengue virus along with the other members of the flaviviridae family has reemerged as deadly human pathogens. Understanding the mechanistic details of these infections can be highly rewarding in developing effective antivirals. During maturation of the virus inside the host cell, the coat proteins E and M undergo conformational changes, altering the morphology of the viral coat. However, due to low resolution nature of the available 3-D structures of viral assemblies, the atomic details of these changes are still elusive. Results: In the present analysis, starting from C alpha positions of low resolution cryo electron microscopic structures the residue level details of protein-protein interaction interfaces of dengue virus coat proteins have been predicted. By comparing the preexisting structures of virus in different phases of life cycle, the changes taking place in these predicted protein-protein interaction interfaces were followed as a function of maturation process of the virus. Besides changing the current notion about the presence of only homodimers in the mature viral coat, the present analysis indicated presence of a proline-rich motif at the protein-protein interaction interface of the coat protein. Investigating the conservation status of these seemingly functionally crucial residues across other members of flaviviridae family enabled dissecting common mechanisms used for infections by these viruses. Conclusions: Thus, using computational approach the present analysis has provided better insights into the preexisting low resolution structures of virus assemblies, the findings of which can be made use of in designing effective antivirals against these deadly human pathogens.