243 research outputs found
Photoluminescence Characteristics of p-Phenylene Vinylene and Its Derivatives in Solution and in Nanoaggregates
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Development of an experimental apparatus to observe ultrafast phenomena by tender X-ray absorption spectroscopy at PAL-XFEL
No full textUnderstanding the ultrafast dynamics of molecules is of fundamental importance. Time-resolved X-ray absorption spectroscopy (TR-XAS) is a powerful spectroscopic technique for unveiling the time-dependent structural and electronic information of molecules that has been widely applied in various fields. Herein, the design and technical achievement of a newly developed experimental apparatus for TR-XAS measurements in the tender X-ray range with X-ray free-electron lasers (XFELs) at the Pohang Accelerator Laboratory XFEL (PAL-XFEL) are described. Femtosecond TR-XAS measurements were conducted at the Ru L-3-edge of well known photosensitizer tris(bipyridine)ruthenium(II) chloride ([Ru(bpy)(3)](2+)) in water. The results indicate ultrafast photoinduced electron transfer from the Ru center to the ligand, which demonstrates that the newly designed setup is applicable for monitoring ultrafast reactions in the femtosecond domain.
Inducing thermodynamically blocked atomic ordering via strongly driven nonequilibrium kinetics
No full textUltrafast light-matter interactions enable inducing exotic material phases by promoting access to kinetic processes blocked in equilibrium. Despite potential opportunities, actively using nonequilibrium kinetics for material discovery is limited by the poor understanding on intermediate states of driven systems. Here, using single-pulse time-resolved imaging with x-ray free-electron lasers, we found intermediate states of photoexcited bismuth nanoparticles that showed kinetically reversed surface ordering during ultrafast melting. This entropy-lowering reaction was further investigated by molecular dynamics simulations to reveal that observed kinetics were thermodynamically buried in equilibrium, which emphasized the critical role of electron-mediated ultrafast free-energy modification in inducing exotic material phases. This study demonstrated that ultrafast photoexcitations of electrons provide an efficient strategy to induce hidden material phases by overcoming thermodynamic barriers via nonequilibrium reaction pathways.11Nsciescopu
Towards a framework for cloud computing use by governments: Leaders, followers and laggers
No full textThere are large varieties of governmental organizations using clouds in different ways. The purpose of this article is to explore and classify the types of public organizations using cloud computing. This will help to improve our understanding of cloud adoption and use by governments. For this, a systematic review of literature on cloud government (CloudGov) was performed by searching for articles in several databases. The review resulted into the main elements of the framework for classifying cloud use. In addition, using diffusion of innovation and institutional theory a categorization of public organizations was made. When applying the CloudGov framework empirically in government organizations, we identified three types of organizations: Leaders, Followers and Laggers. The types differ in various ways including their technology expertise, attitude towards innovation and level of political support. In further research, we recommend investigating which drivers influence the type of CloudGov users and generalize the framework to other contexts.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Information and Communication Technolog
Future government data strategies: Data-driven enterprise or data steward?: Exploring definitions and challenges for the government as data enterprise
No full textComparable to the concept of a data(-driven) enterprise, the concept of a ggovernment as data (-driven) enterprise' is gaining popularity as a data strategy. However, what it implies is unclear. The objective of this paper is to clarify the concept of the government as data (-driven) enterprise, and identify the challenges and drivers that shape future data strategies. Drawing on literature review and expert interviews, this paper provides a rich understanding of the challenges for developing sound future government data strategies. Our analysis shows that two contrary data strategies dominate the debate. On the one hand is the data-driven enterprise strategy that focusses on collecting and using data to improve or enrich government processes and services (internal orientation). On the other hand, respondents point to the urgent need for governments to take on data stewardship, so other parties can use data to develop value for society (external orientation). Since these data strategies are not mutually exclusive, some government agencies will attempt to combine them, which is very difficult to pull off. Nonetheless, both strategies demand a more data minded culture. Moreover, the successful implementation of either strategy requires mature data governance - something most organisations still need to master. This research contributes by providing more depth to these strategies. The main challenge for policy makers is to decide on which strategy best fits their agency's roles and responsibilities and develop a shared roadmap with the external actors while at the same time mature on data governance.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Information and Communication Technolog
A new approach to institutional domain analysis: Multilevel research fronts structure
No full textThe intellectual structure and main research fronts of the Faculty of Natural Sciences and
Museum of the National University of La Plata, Argentina is studied, based on the cocitation analysis of subject categories, journals and authors of their scientific publications collected in the Science Citation Index, CD-ROM version, for the period 1991–2000. The objective of this study is to test the utility of those techniques to explore and to visualize the intellectual structure and research fronts of multidisciplinary institutional domains. Special emphasis is laid on the identification of multilevel structures, by means of arrangements of subject categories cocitation analysis and journal cocitation analysis
Longitudinal author cocitation mapping: the changing structure of decision support systems research (1969-2012)
No full textLongitudinal Author Cocitation Mapping focuses on specific aspects of the decision support systems (DSS) history by means of an empirical assessment of the DSS literature over three consecutive time periods: 1969-1990, 1991- 2005, and 2006-2012
Citizens’ Trust in Open Government Data: A Quantitative Study about the Effects of Data Quality, System Quality and Service Quality
No full textPrevious research assumes that poor quality of Open Government Data (OGD), OGD portals, and the services provided for OGD may result in reduced trust of citizens in OGD. However, studies that empirically test this assumption are scarce. Using the Information Systems (IS) Success Model as a theoretical basis, this study aims to examine the effects of data quality, system quality, and service quality on citizens’ trust in OGD.We used Structural Equation Modeling (SEM) to analyze the 200 responses to our online questionnaire. We found that trust in OGD can be predicted by citizens’ perceptions of OGD system quality and service quality. Furthermore, citizens’ perception of service quality positively influences their perceptions of data and system quality, whereas citizens’ perception of system quality positively influences their perception of data quality. This study is among the first that quantitatively examines the effects of data quality, service quality, and system quality on citizen’s trust in OGD. It contributes to the scientific literature by providing an operationalization of elements of the IS Success Model in the context of OGD and by developing and applying a model of factors influencing citizen’s trust in OGD. While previous research finds that perceived data quality is the most crucial driver for trust in OGD, our study finds that citizens’ perception of OGD service quality is a more important driver for trust in OGD. With regard to the practical contributions of this study, open data policymakers should be aware that citizens’ perceptions on data quality can be greatly improved when appropriate human services are provided (e.g., designated civil servants offering support or help to data users) in addition to the provision of OGD portal functionalities (e.g., data visualization and comparison tools).Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Information and Communication Technolog
COMPARATIVE ANALYSIS OF THE RENNER EFFECT IN THE STATE OF CCO, CSiO, SiCO, AND SiSiO WITH EQUATION OF MOTION COUPLED CLUSTER THEORY (EOM-CCSD)
No full text Devillers, M. C. and Ramsay, D. A., Can. J. Phys., 1971 49, 2839.Author Institution: Center for Computational Quantum Chemistry, University of GeorgiaEquation of motion coupled cluster theory (EOM-CCSD) has been employed to systematically study the Renner effect in the first triplet excited state in a series of CCO radical analogues (14 valence electrons). The total energies and physical properties including equilibrium geometries, dipole moments, and harmonic vibrational frequencies of CCO, CSiO, SiCO, and SiSiO were predicted using SCF, CISD, CCSD, CCSD(T) and EOM-CCSD with a wide range of basis sets. The state of all these molecules are linear at equilibrium. The potential energy surface of the state of the CCO analogues splits into and states on bending and each surface has its own minimum at the linear configuration. The two distinct bending frequencies were determined and used to predict the Renner parameter, and the average harmonic bending frequency. , neglecting anharmonicity and spin-orbit coupling effects. Theoretically predicted harmonic stretching vibrational frequencies of were in close agreement with experimental fundamental frequencies, indicating relatively small anharmonicities. The relative ordering of the Renner splitting at the EOM-CCSD level of theory with a TZ3P(2f) basis for this series of radicals was determined to be . The computation of resulted in negative values for all of these radicals due to the energy ordering of the split potential energy surfaces. The predicted for CCO (-0.153 at TZ3P(2f) EOM-CCSD) is good agreement with the value of -0.172 from Devillers and experimental analysis
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