574 research outputs found
Resource-based View in Information Systems Research: A Meta-Analysis
Resource-based view is the theory that has been applied to analyze the impact of informa-tion technology on business performance. Its main argument is that competitive advan-tages are determined by the unique valuable resources controlled by an organization. IT as a valuable asset will have positive effect on firm performance. However, previous re-search on the issue is inconsistent. This paper reports a meta analysis of 42 papers pub-lished in major journals in information systems. Our findings indicate that the capability mediated model is better than the direct effect model and the major impact of IT is on ef-ficiency indicators
Stimulation of Beta Decay due to a Bose-Einstein Condensate
Nuclear processes can be stimulated by the presence of a macroscopic number
of bosons in one of the final states. We describe the conditions necessary to
observe the atom-stimulation of a beta decay process. The stimulation may be
observable if it becomes possible to produce a Bose-Einstein condensate with
the order of atoms in a trap.Comment: 7 pages, LaTeX, uses elsart.cls, home page at
http://online.anu.edu.au/Physics/Welcome.htm
Consistent response to guselkumab treatment between Hispanic and non-Hispanic patients with psoriasis : an analysis from VOYAGE 1 and VOYAGE 2
Altres ajuts: Janssen Research and Development (JRD)Introduction: In VOYAGE 1 (NCT02207231) and VOYAGE 2 (NCT02207244), guselkumab, an interleukin-23 blocker, was safe and effective in patients with moderate-to-severe plaque psoriasis. Methods: Patients who self-identified as Hispanic (n = 117) or non-Hispanic (n = 1686) were randomized to guselkumab, placebo, or adalimumab. Efficacy assessments included Psoriasis Area and Severity Index (PASI), Investigator's Global Assessment (IGA), and Dermatology Life Quality Index (DLQI). Results: At week 16, treatment differences for guselkumab versus placebo in the Hispanic and non-Hispanic populations were 67.4 (95% confidence interval 50.4, 84.4) and 77.2 (73.5, 80.8) percentage points for IGA 0/1 and 59.2 (41.9, 76.4) and 69.2 (65.7, 72.7) percentage points for PASI 90, respectively. Treatment differences for guselkumab versus adalimumab were 25.9 (6.5, 45.3) and 17.5 (12.8, 22.3) percentage points for IGA 0/1 and 21.4 (-0.1, 42.9) and 23.5 (18.2, 28.9) percentage points for PASI 90, respectively. Week 24 results were similar. Adverse event frequency was greater in adalimumab- versus guselkumab-treated patients in the Hispanic population only through weeks 16 and 28. In both populations, DLQI 0/1 responses were greater in guselkumab-treated versus placebo- and adalimumab-treated patients at week 16 and versus adalimumab-treated patients at week 24. Conclusions: Guselkumab safety and efficacy were consistent between Hispanic and non-Hispanic populations
Green Solvent Processed Conjugated Polymers for Organic Solar Cells: The Impact of Oligoethylene Glycol Side Chains
Organic photovoltaics (OPVs) possess the advantageous trait of solution processability, yet OPV blends typically use hazardous chlorinated solvents for processing. In order to realize the full advantages of OPVs, as well as growing to an industrial scale, the use of environmentally friendly solvents for processing OPVs needs to be pursued. In this study, we utilized the well-studied polymer PBnDT-FTAZ system as the model conjugated polymer, and synthesized a series of structurally similar conjugated polymers with oligo(ethylene glycol) (OEG) side-chains, aiming to understand the structural requirements to convert conventional conjugated polymers into green-processable alternatives. We elucidated the impact of these OEG chains on the properties of modified polymers when compared with the original PBnDT-FTAZ, including solubility and optoelectronic properties. Finally, aiming to understand the impact of changing side chains to the device performance, we fabricated solar cells with a nonfullerene acceptor (IT-M), achieving decent device efficiencies (over 7%). Additionally, using renewable and green solvent, 2-methyltetrahydrofuran (2-MeTHF), we were able to achieve device efficiencies of over 2%
A carbon-oxygen-bridged hexacyclic ladder-type building block for low-bandgap nonfullerene acceptors
A hexacyclic carbon-oxygen-bridged ladder-type unit, COi6, was developed. Three nonfullerene acceptors (COi6IC, COi6FIC and COi6DFIC) based on COi6 were prepared. They present low optical bandgaps of 1.31-1.37 eV and strong absorbance in the near-infrared region. A 9.12% power conversion efficiency was achieved from the solar cells based on COi6FIC and a wide-bandgap copolymer donor (FTAZ)
Utilizing Difluorinated Thiophene Units to Improve the Performance of Polymer Solar Cells
While there are numerous approaches to functionalize conjugated polymers for organic solar cells (OSCs), one widely adopted approach is fluorination. Of the many different locations for fluorination, one of the least studied is the conjugated linker which connects the donor and acceptor moieties; further, all existing reports primarily explore monofluorinated thiophene units. Herein, we synthesize and compare two conjugated polymers, HTAZ and DFT-HTAZ, which have different thiophene linkers. In HTAZ, a bare thiophene unit connects the donor and acceptor moieties, while DFT-HTAZ utilizes difluorinated thiophene (DFT) linkers. These polymers serve as the model system to explore the impact of DFT units in OSCs; additionally, this is the first publication to investigate polymers containing DFT units paired with non-fullerene acceptors. Compared to HTAZ, the incorporation of the DFT units maintained the optical properties while lowering the energy levels by â0.4 eV, which allowed for a much improved Voc value of â1 V. Importantly, when compared with the appropriate non-fullerene acceptor, DFT-HTAZ:ITIC-Th1 blends reached an efficiency of â10%, which is nearly 3à that of the nonfluorinated HTAZ. As most OSC polymers have thiophene linkers, using DFT units could serve as a proficient method to increase OSC performance in many polymer systems, especially those that do not have locations for functionalization on the acceptor moiety
The Importance of Entanglements in Optimizing the Mechanical and Electrical Performance of All-Polymer Solar Cells
Organic solar cells that have all-polymer active layers may have several advantages compared with polymer-small molecule systems including improved mechanical and thermodynamic stability; however, an all-polymer active layer does not guarantee robust mechanical behavior. Here, we consider key parameters that may influence the mechanical behavior and power conversion efficiency of all-polymer solar cells (all-PSCs). Considerations include the thermal transition temperature of the polymers, the molecular weight (MW) of the polymers, and film morphology. The impact these features have on mechanical behavior is probed by measuring the cohesive fracture energy (Gc), crack onset strain, and elastic modulus. We find that the selection of ductile polymers with high MW enhances interchain interactions that improve the mechanical resilience of the films. High-MW polymers are also found to maximize the power conversion efficiency (PCE). Using this strategy, BHJ films with the best reported combination of Gc (7.96 J m-2) and PCE (6.94%) are demonstrated. Finally, it is found that increasing the film thickness increases the fracture energy of the films but at the cost of PCE. These findings provide a fundamental perspective on the design strategy to achieve high performance and mechanically robust organic solar cells
Revealing the Impact of F4-TCNQ as Additive on Morphology and Performance of High-Efficiency Nonfullerene Organic Solar Cells
Fluorinated molecule 2,3,5,6âtetrafluoroâ7,7,8,8âtetracyanoquinodimethane (F4âTCNQ) and its derivatives have been used in polymer:fullerene solar cells primarily as a dopant to optimize the electrical properties and device performance. However, the underlying mechanism and generality of how F4âTCNQ affects device operation and possibly the morphology is poorly understood, particularly for emerging nonfullerene organic solar cells. In this work, the influence of F4âTCNQ on the blend film morphology and photovoltaic performance of nonfullerene solar cells processed by a single halogenâfree solvent is systematically investigated using a set of morphological and electrical characterizations. In solar cells with a highâperformance polymer:small molecule blend FTAZ:ITâM, F4âTCNQ has a negligibly small effect on the molecular packing and surface characteristics, while it clearly affects the electronic properties and meanâsquare composition variation of the bulk. In comparison to the control devices with an average power conversion efficiency (PCE) of 11.8%, inclusion of a trace amount of F4âTCNQ in the active layer has improved device fill factor and current density, which has resulted into a PCE of 12.4%. Further increase in F4âTCNQ content degrades device performance. This investigation aims at delineating the precise role of F4âTCNQ in nonfullerene bulk heterojunction films, and thereby establishing a facile approach to fabricate highly optimized nonfullerene solar cells
Charmonium states in QCD-inspired quark potential model using Gaussian expansion method
We investigate the mass spectrum and electromagnetic processes of charmonium
system with the nonperturbative treatment for the spin-dependent potentials,
comparing the pure scalar and scalar-vector mixing linear confining potentials.
It is revealed that the scalar-vector mixing confinement would be important for
reproducing the mass spectrum and decay widths, and therein the vector
component is predicted to be around 22%. With the state wave functions obtained
via the full-potential Hamiltonian, the long-standing discrepancy in M1
radiative transitions of and are alleviated
spontaneously. This work also intends to provide an inspection and suggestion
for the possible among the copious higher charmonium-like states.
Particularly, the newly observed X(4160) and X(4350) are found in the
charmonium family mass spectrum as MeV and MeV, which strongly favor the assignments
respectively. The corresponding radiative transitions, leptonic and two-photon
decay widths have been also predicted theoretically for the further
experimental search.Comment: 16 pages,3 figure
Model study on the photoassociation of a pair of trapped atoms into an ultralong-range molecule
Using the method of quantum-defect theory, we calculate the ultralong-range
molecular vibrational states near the dissociation threshold of a diatomic
molecular potential which asymptotically varies as . The properties of
these states are of considerable interest as they can be formed by
photoassociation (PA) of two ground state atoms. The Franck-Condon overlap
integrals between the harmonically trapped atom-pair states and the
ultralong-range molecular vibrational states are estimated and compared with
their values for a pair of untrapped free atoms in the low-energy scattering
state. We find that the binding between a pair of ground-state atoms by a
harmonic trap has significant effect on the Franck-Condon integrals and thus
can be used to influence PA. Trap-induced binding between two ground-state
atoms may facilitate coherent PA dynamics between the two atoms and the
photoassociated diatomic molecule.Comment: 11 pages, 4 figures, to appear in Phys. Rev. A (September, 2003
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