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141.
Schilling Carolin Zähres Manfred Mayer Christian Winterer Markus 《Journal of nanoparticle research》2014,16(7):1-15
Printed electronics, as an extension to conventional electronics, has grown considerably for decades. At this moment, therefore, tracing the development of this technology up to the present will provide researchers and R&D planners with better understanding of the technology’s evolving characteristics and insights for further R&D directions. This paper carries out two bibliographic analyses to study the technology development life cycle and the technological knowledge within the area of printed electronics. First, we fit a growth curve to yearly patent registration data, thereby calculating several indicators, including the current technological maturity ratio, the number of potential future patents and the expected remaining life. Second, we identify the core and brokering technology classes within the overall technology network of printed electronics by combining patent co-classification analysis and social network analysis. As a result, we could obtain some findings from the inventional point of view; the technological development of printed electronics has entered the maturity stage, and the expected remaining life was 8.5 years as of the beginning of 2013. In addition, we identified several technology areas that have the high importance to act as both core and brokering technologies, apparatus for metal working, anti-inductive structures, and electronic circuit control systems. 相似文献
142.
143.
Aaron C. West Joseph D. Lynch Bernhard Sellner Hans Lischka William L. Hase Theresa L. Windus 《Theoretical chemistry accounts》2012,131(10):1-14
Extensive density functional theory (DFT) calculations have been performed to develop a force field for the classical molecular dynamics (MD) simulations of various azobenzene derivatives. Besides azobenzene, we focused on a thiolated azobenzene’s molecular rod (4′-{[(1,1′-biphenyl)-4-yl]diazenyl}-(1,1′-biphenyl)-4-thiol) that has been previously demonstrated to photoisomerize from trans to cis with high yields on surfaces. The developed force field is an extension of OPLS All Atoms, and key bonding parameters are parameterized to reproduce the potential energy profiles calculated by DFT. For each of the parameterized molecule, we propose three sets of parameters: one best suited for the trans configuration, one for the cis configuration, and finally, a set able to describe both at a satisfactory degree. The quality of the derived parameters is evaluated by comparing with structural and vibrational experimental data. The developed force field opens the way to the classical MD simulations of self-assembled monolayers (SAMs) of azobenzene’s molecular rods, as well as to the quantum mechanics/molecular mechanics study of photoisomerization in SAMs. 相似文献
144.
Wang N Lu JS McCormick TM Wang S 《Dalton transactions (Cambridge, England : 2003)》2012,41(18):5553-5561
A new ligand p-[N-2-(2'-pyridyl)benzimidazolyl]-[N-2-(2'-pyridyl)indolyl]-benzene (L1) has been synthesized and fully characterized. L1 has two distinct chelating sites: one N,N-chelate site and one N,C-chelate site. This ligand has been found to be very effective in selective binding to two different metal ions. Two new heterobimetallic complexes Ru-Pt and Ru-Pd using L1 as the bridging ligand have been successfully synthesized and fully characterized. To understand the mutual influence of the two metal centers on electronic and photophysical properties, the corresponding monometallic Ru(II), Pt(II) and Pd(II) compounds have also been synthesized and investigated. All Ru(II)-containing complexes have been found to be luminescent. Electronic communication between the two different metal centers in the heterobimetallic compounds was found to be weak. The Pt(II) moiety appears to enhance the phosphorescent efficiency of the Ru(II) unit while the Pd(II) analogue has little influence. 相似文献
145.
We have synthesized a series of cyclopentadithiophene-benzochalcogenodiazole donor-acceptor (D-A) copolymers, wherein a single atom in the benzochalcogenodiazole unit is varied from sulfur to selenium to tellurium, which allows us to explicitly study sulfur to selenium to tellurium substitution in D-A copolymers for the first time. The synthesis of S- and Se-containing polymers is straightforward; however, Te-containing polymers must be prepared by postpolymerization single atom substitution. All of the polymers have the representative dual-band optical absorption profile, consisting of both a low- and high-energy optical transition. Optical spectroscopy reveals that heavy atom substitution leads to a red-shift in the low-energy transition, while the high-energy band remains relatively constant in energy. The red-shift in the low-energy transition leads to optical band gap values of 1.59, 1.46, and 1.06 eV for the S-, Se-, and Te-containing polymers, respectively. Additionally, the strength of the low-energy band decreases, while the high-energy band remains constant. These trends cannot be explained by the present D and A theory where optical properties are governed exclusively by the strength of D and A units. A series of optical spectroscopy experiments, solvatochromism studies, density functional theory (DFT) calculations, and time-dependent DFT calculations are used to understand these trends. The red-shift in low-energy absorption is likely due to both a decrease in ionization potential and an increase in bond length and decrease in acceptor aromaticity. The loss of intensity of the low-energy band is likely the result of a loss of electronegativity and the acceptor unit's ability to separate charge. Overall, in addition to the established theory that difference in electron density of the D and A units controls the band gap, single atom substitution at key positions can be used to control the band gap of D-A copolymers. 相似文献
146.
Photonic nanobeam microcavities are devices for applications where strong light–matter-interaction is needed. They are characterized by a strong field enhancement in a small volume, which can be used for nonlinear optical applications. To enhance such effects, a solid microcavity can be replaced by a slot, that can be infiltrated with a material of choice (e.g. chalcogenide glasses or nonlinear polymers). Here, the parameters needed to create high quality nanobeam slot microcavities are numerically investigated. Design rules for the minimization of scattering losses and thus the enhancement of the Q factor are reviewed and discussed. 相似文献
147.
Holly D. Bendorf Kyle E. Ruhl Andrew J. Shurer Jennie B. Shaffer Tess O. Duffin Theresa L. LaBarte Michelle L. Maddock Oscar W. Wheeler 《Tetrahedron letters》2012,53(10):1275-1277
Medium-ring heterocycles are prepared via an amine-directed, rhodium(I)-catalyzed intramolecular hydroacylation. The presence of an allyl substituent on the amine accelerates the reaction and increases product yields. 相似文献
148.
149.
Sides CR Liyanage R Lay JO Philominathan ST Matsushita O Sakon J 《Journal of the American Society for Mass Spectrometry》2012,23(3):505-519
Pairing limited proteolysis and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS)
to probe clostridial collagenase collagen binding domain (CBD) reveals the solution dynamics and stability of the protein,
as these factors are crucial to CBD effectiveness as a drug-delivery vehicle. MS analysis of proteolytic digests indicates
initial cleavage sites, thereby specifying the less stable and highly accessible regions of CBD. Modulation of protein structure
and stability upon metal binding is shown through MS analysis of calcium-bound and cobalt-bound CBD proteolytic digests. Previously
determined X-ray crystal structures illustrate that calcium binding induces secondary structure transformation in the highly
mobile N-terminal arm and increases protein stability. MS-based detection of exposed residues confirms protein flexibility,
accentuates N-terminal dynamics, and demonstrates increased global protein stability exported by calcium binding. Additionally,
apo- and calcium-bound CBD proteolysis sites correlate well with crystallographic B-factors, accessibility, and enzyme specificity.
MS-observed cleavage sites with no clear correlations are explained either by crystal contacts of the X-ray crystal structures
or by observed differences between Molecules A and B in the X-ray crystal structures. The study newly reveals the absence
of the βA strand and thus the very dynamic N-terminal linker, as corroborated by the solution X-ray scattering results. Cobalt
binding has a regional effect on the solution phase stability of CBD, as limited proteolysis data implies the capture of an
intermediate-CBD solution structure when cobalt is bound. 相似文献
150.
We study for a class of symmetric Lévy processes with state space R n the transition density pt(x) in terms of two one-parameter families of metrics, (dt)t>0 and (δt)t>0. The first family of metrics describes the diagonal term pt(0); it is induced by the characteristic exponent ψ of the Lévy process by dt(x, y) = 1/2tψ(x-y). The second and new family of metrics δt relates to 1/2tψ through the formulawhere F denotes the Fourier transform. Thus we obtain the following "Gaussian" representation of the transition density: pt(x) = pt(0)e- δ2t (x,0) where pt(0) corresponds to a volume term related to tψ and where an "exponential" decay is governed by δ2t . This gives a complete and new geometric, intrinsic interpretation of pt(x). 相似文献