Preparation of Zinc Titanate Thin Films by Low-Pressure Metalorganic Chemical Vapor Deposition

Homogeneous thin films of zinc titanate have been successfully prepared on Si(100) wafers by depositing a film of zinc and titanium oxides (ZnO-TiO₂) by low-pressure metalorganic chemical vapor deposition (MOCVD), followed by an annealing treatment. The precursors used for the deposition were diethylzinc (DEZ), tetraisopropoxide titanium (TPT), and water. By performing the deposition at temperatures between 140 and 350C, the stoichiometry of the as-deposited films could be effectively controlled over Zn/Ti ratios between 0.5 and 2.5, which cover the composition of various zinc titanate phases identified in the literature. The as-deposited ZnO-TiO₂ films are amorphous, and possess a fairly smooth surface. XPS and SIMS analysis showed that the composition of these films is uniform over the wafer as well as through the films bulk. An annealing treatment of the as-deposited films at high temperature     

PROBA-V mission for global vegetation monitoring: standard products and image quality

PROBA-V is a new global vegetation monitoring mission, to be launched in the second quarter of 2013. PROBA-V has been developed to show a consistent performance with SPOT-VEGETATION (SPOT-VGT) data, with similar spectral bands but with an improved spatial resolution of 1/3 km. The innovative mission concept has led to several key research topics related to image quality, which are discussed in this article. To support the existing VEGETATION user community, the data products for PROBA-V continue to provide daily top of canopy synthesis (S1-TOC) and 10 day synthesis products (S10-TOC). In addition, the new top of atmosphere daily synthesis (S1-TOA) products and a radiometrically/geometrically corrected (level 1C) product in raw resolution will also be provided for scientific users.     

Change patterns

Change, such as in the requirements or the assumptions of a system, has a far-reaching impact across several software artifacts. This paper argues that patterns of co-evolution (or change patterns) can be observed between intertwined pairs of artifacts, like the requirements specification and the architectural design. The paper introduces change patterns as a precise framework to systematically capture and handle change. The approach is based on model-driven engineering concepts and is accompanied by a tool-supported process. Changing trust assumptions are presented as an example of security-related evolution, and are used to illustrate the approach. The approach is empirically validated by means of a controlled experiment involving 12 subjects, and a case study involving an industrial partner.     

Leaving the third dimension: no measurable evidence for cognitive aftereffects of stereoscopic 3D movies

Stereoscopic 3D (S‐3D) is becoming an increasingly important display technology. Parallel to this, concern about the potential negative effects of exposure to S‐3D movies has been growing. Some manufacturers place disclaimers on their TVs advising people to limit the time they watch S‐3D. However, surprisingly little experimental research has been conducted estimating the genuineness of these concerns. Therefore, an experiment was designed to assess the potential impact of viewing an S‐3D movie on visual, spatial, and general attention performance. To mimic the real‐world experience of watching a movie in the living room, participants (N = 61) watched a full movie in either 2D or S‐3D. Our results do not show evidence for cognitive aftereffects of S‐3D movies. A second experiment (N = 32) that focused on possible aftereffects on visual attention also failed to find reliable effects. We therefore conclude that cognitive functioning is not altered by watching an S‐3D movie, at least not to an extent that is measurable through well‐established cognitive tasks.     

Illustrative Molecular Visualization with Continuous Abstraction

Molecular systems may be visualized with various degrees of structural abstraction, support of spatial perception, and ‘illustrativeness.’ In this work we propose and realize methods to create seamless transformations that allow us to affect and change each of these three parameters individually. The resulting transitions give viewers a dedicated control of abstraction in illustrative molecular visualization and, consequently, allow them to seamlessly explore the resulting abstraction space for obtaining a fundamental understanding of molecular systems. We show example visualizations created with our approach and report informal feedback on our technique from domain experts.     

Silver Zeolite Composites‐Based LEDs: A Novel Solid‐State Lighting Approach

Silver clusters incorporated in a zeolite matrix represent a promising alternative for rare earth phosphors, organic dyes, and quantum dots as emitters in organic and hybrid organic/inorganic light‐emitting diodes (OLEDs). Compared to other existing types of emitters, they combine an excellent stability to oxygen and humidity with a high luminescence quantum yield and color tunability. This study reports on the first use of these silver exchanged zeolites embedded in polyvinyl carbazole (PVK), which is expected to act as a conducting matrix, as emitters in a single‐layer OLED. It is demonstrated that the introduction of these Ag zeolites leads to electroluminescence bands that clearly differ from pristine PVK OLEDs as well as from the photoluminescence spectra of the Ag zeolites. The current density and the spectral properties observed in these devices are strongly influenced by the zeolite silver loading, paving the way for a new type of easily tunable hybrid and cost‐effective OLEDs.     

Linking historic developments and future scenarios of industrial energy use in the Netherlands between 1993 and 2040

Monitoring energy efficiency improvements is essential for policy evaluation and for future policy making. We estimate the annual energy efficiency improvements achieved in six Dutch industry sectors between 1993 and 2008 by using a bottom-up model. This model incorporates the production data and specific energy consumption values of 122 products. We estimate annual energy efficiency improvements of 1.0 % per annum (p.a.) for the total industry (excluding non-energy use); even though the results are subject to uncertainties due to errors in the energy statistics, we consider them as strong indication that Dutch industry needs to reinforce its efforts in energy efficiency. Based on historical achievements between 1989 and 2008, Business as Usual (BaU) scenarios project annual improvement potentials of 0.6–1.8 % p.a. until 2040. Based on literature review, this study estimates that implementing energy saving technologies can accelerate energy efficiency improvements to 2 % p.a. and beyond. Efficient combined heat and power technologies could increase these potentials further. These are beyond the historical achievements and BaU scenario projections. New policies will be required for technology development which ensures continuous energy efficiency improvements. The findings of this paper need to be extended by continuous monitoring and more scenario analyses with improved data.     

Nematic DNA Thermotropic Liquid Crystals with Photoresponsive Mechanical Properties

Over the last decades, water‐based lyotropic liquid crystals of nucleic acids have been extensively investigated because of their important role in biology. Alongside, solvent‐free thermotropic liquid crystals (TLCs) from DNA are gaining great interest, owing to their relevance to DNA‐inspired optoelectronic applications. Up to now, however, only the smectic phase of DNA TLCs has been reported. The development of new mesophases including nematic, hexagonal, and cubic structures for DNA TLCs remains a significant challenge, which thus limits their technological applications considerably. In this work, a new type of DNA TLC that is formed by electrostatic complexation of anionic oligonucleotides and cationic surfactants containing an azobenzene (AZO) moiety is demonstrated. DNA–AZO complexes form a stable nematic mesophase over a temperature range from ?7 to 110 °C and retain double‐stranded DNA structure at ambient temperature. Photoisomerization of the AZO moieties from the E‐ to the Z‐ form alters the stiffness of the DNA–AZO hybrid materials opening a pathway toward the development of DNA TLCs as stimuli‐responsive biomaterials.     

Impacts of energy-efficiency investments on internal conditions in low-income households

Living in cold conditions poses a risk to health, in particular to low-income, fuel-poor households. Improving the energy efficiency of the housing stock may bring multiple positive health gains through improved indoor temperatures and reduced fuel consumption. This study used a multilevel interrupted time-series approach to evaluate a policy-led energy-performance investment programme. Long-term monitoring data were collected for intervention and control households at baseline (n?=?99) and follow-up (n?=?88), creating a dataset with 15,771 data points for a series of daily-averaged hydrothermal outcome variables. The study found that the intervention raised indoor air temperature by on average 0.84?K as compared with control households, thereby bringing the majority of indoor temperature measurements within the ‘healthy’ comfort zone of 18–24°C, while average daily gas usage dropped by 37%. External wall insulation was the most effective measure to increase indoor air temperature. The greatest increases were found in the evening and at night, in the bedroom, and in British steel-framed buildings. No evidence was found that the intervention substantially increased indoor relative humidity levels when accompanied by mechanical ventilation. The study concludes that the multilevel interrupted time-series approach offers a useful model for evaluating housing improvement programmes.