One of the most appealing properties of carbon nanotube (CNT) interconnects is the possibility of exhibiting, under certain circumstances, a negative temperature coefficient of the electrical ...resistance, i.e., a resistance that decreases as temperature increases. In the past, this behavior has been theoretically predicted and experimentally observed, but only for a certain class of CNTs, with short lengths (up to some micrometers) and in a limited range of temperature. This paper demonstrates the possibility of obtaining such a desirable behavior in a larger scale (up to fractions of millimeters). An accurate electrothermal model is used to define the conditions under which a negative derivative of the resistance may be observed. Then, a novel bottom-up technique is proposed to realize the interconnect, by self-assembly of short CNTs. The experimental results of an electrothermal characterization demonstrate the possibility of obtaining a negative temperature coefficient of the resistance and confirm the validity of the theoretical model.
The complexation between 2‐ureido‐41H‐pyrimidinone (UPy) and 2,7‐diamido‐1,8‐naphthyridine (NaPy) is used to promote the mild chemisorption of a UPy‐functionalized terbium(III) double decker system ...on a silicon surface. The adopted strategy allows the single‐molecule magnet behavior of the system to be maintained unaltered on the surface.
A strategy based on multiple hydrogen bonding leads to a monolayer of terbium double decker molecules assembled on silicon maintaining unaltered their single molecule magnet behavior.
A hierarchical hybrid inorganic–organic system suited for the recognition of aromatic volatile organic compounds on brushlike ZnO fibers was synthetized. The hybrid material was obtained by a ...multistep approach based on the growth of ZnO nanorods onto electrospun ZnO fibers (average diameter 200 nm). The obtained nanostructured ZnO brushlike fibers (overall diameter 2 μm) were functionalized through the grafting of a bifunctional phosphonic linker (12-azidododecylphosphonic acid) followed by the anchoring of a specific cavitand receptor. The linker was anchored on ZnO fibers through the phosphonic group while the azide terminations reacted with a quinoxaline-bridged cavitand (QxCav) having four alkyne groups via “click” reaction. The anchoring steps were monitored through the evolution of the FT-IR features in the 3200–2800 cm–1 region due to C–H x stretches and in the 2200–2000 cm–1 region due to the azide and alkyne groups of the phosphonic linker and QxCav. The recognition properties of this hybrid nanostructure toward α,α,α-trifluorotoluene vapors were evaluated by XPS and Raman measurements.
The complexation between 2-ureido-41H-pyrimidinone (UPy) and 2,7-diamido-1,8-naphthyridine (NaPy) is used to promote the mild chemisorption of a UPy-functionalized terbium(III) double decker system ...on a silicon surface. The adopted strategy allows the single-molecule magnet behavior of the system to be maintained unaltered on the surface.
This Letter proposes the use of a modal pattern stability factor (MPSF) parameter to quantify the pattern stability associated to characteristic modes (CM). The proposed parameter can be used as a ...figure of merit for CM associated to arbitrary-shaped structures, aiding the antenna design process. This parameter can be used (together with other modal parameters) to optimise the geometry of a radiating element in order to improve the radiation pattern stability in a desired range of frequencies. Two examples are presented for analysis. First, MPSF for the CM of three ring antennas with different width are analysed, showing how pattern stability of CM depend on this geometrical parameter. Secondly, three metallic plates with different shapes are analysed in terms of MPSF, in order to assess the stability of the CM for each geometry.
Transparent MOCVD‐grown NiO films have been functionalized with the luminescent (1,10‐phenanthroline)tris(2‐thenoyltrifluoroacetonato)europium(III) complex Eu(TTA)3phen by combining sputter ...activation with a solution synthetic route. To introduce the Eu complex only on selected regions, some areas of the NiO surface were activated by Ar+ ion sputtering and then functionalized with 3‐phosphonopropionic acid (CPPA) followed by the anchoring of Eu(TTA)3phen through a ligand‐exchange reaction between β‐diketonato ligands and the carboxylic groups of CPPA. The functionalized material was characterized by X‐ray photoelectron, UV/Vis and luminescence spectroscopy. XPS measurements indicated that CPPA prefunctionalization and, in turn, the Eu(TTA)3phen anchoring occurs only on the sputter‐activated region, while no anchoring takes place on the unactivated surface. The optical properties of the Eu(TTA)3phen–NiO system were evaluated by UV/Vis and luminescence spectroscopy.
Anchoring of the Eu(TTA)3phen complex on MOCVD‐grown NiO films is reported. The NiO surface was activated by means of a sputtering process and functionalized with a phosphonic linker, followed by the coordination of the Eu complex through a ligand‐exchange reaction. The luminescent hybrid system has been proven to retain the optical properties of the Eu complex.
Nanocolumnar Si substrates (porous silicon (PSi)) have been functionalized with a quinoxaline-bridged (EtQxBox) cavitand in which the quinoxaline moieties are bonded to each other through four ...ethylendioxy bridges at the upper rim of the cavity. The receptor, which is known to selectively complex aromatic volatile organic compounds (VOCs) even in the presence of aliphatic compounds, has been covalently anchored to PSi. The larger surface area of PSi, compared to that of flat substrates, allowed one to study the recognition process of the surface-grafted receptors through different techniques: Fourier-transform infrared spectroscopy, thermal desorption, and X-ray photoelectron spectroscopy. The experiments proved that surface-grafted cavitands retain the recognition capability toward aromatic VOCs. In addition, the affinities of EtQxBox for various aromatic compounds (i.e., benzene, toluene, nitrobenzene, and p-nitrotoluene) have been studied combining density functional theory computations and thermal desorption experiments. Computational data based on the crystal structures of the complexes indicate that this cavitand possesses a higher affinity toward aromatic nitro-compounds compared to benzene and toluene, making this receptor of particular interest for the detection of explosive taggants. The results of computational studies have been validated also for the surface-grafted receptor through competitive recognition experiments. These experiments showed that EtQxBox-functionalized PSi can recognize nitrobenzene in the presence of a significant excess of aromatic vapors such as benzene (1:300) or toluene (1:100).
Some strains of
(
) and
(
) efficiently synthesize medium-chain-length polyhydroxyalkanoates elastomers (mcl-PHA) and extracellular products on related and unrelated carbon sources. Yield and ...composition are dependent on the strain, carbon source, fermentation process, and any additives. Selected
strains produce amorphous and sticky mcl-PHA, whereas strains of
produce, on high grade and partially refined biodiesel glycerol, a distinctive filmable PHA, very different from the conventional microbial mcl-PHA, suitable for making blends with polylactide acid. However, the yields still need to be improved and production costs lowered. An integrated process has been developed to recover intracellular mcl-PHA and extracellular bioactive molecules. Transcriptional regulation studies during PHA production contribute to understanding the metabolic potential of
and
strains. Data available suggest that
biosynthesis genes and their regulations will be helpful to develop new, integrated strategies for cost-effective production.
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