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51.
Nanotechnology can be described as an emerging technology and, as has been the case with other emerging technologies such
as genetic modification, different socio-psychological factors will potentially influence societal responses to its development
and application. These factors will play an important role in how nanotechnology is developed and commercialised. This article
aims to identify expert opinion on factors influencing societal response to applications of nanotechnology. Structured interviews
with experts on nanotechnology from North West Europe were conducted using repertory grid methodology in conjunction with
generalized Procrustes analysis to examine the psychological constructs underlying societal uptake of 15 key applications
of nanotechnology drawn from different areas (e.g. medicine, agriculture and environment, chemical, food, military, sports,
and cosmetics). Based on expert judgement, the main factors influencing societal response to different applications of nanotechnology
will be the extent to which applications are perceived to be beneficial, useful, and necessary, and how 'real' and physically
close to the end-user these applications are perceived to be by the public. 相似文献
52.
Fabrication of Polyhedral Particles from Spherical Colloids and Their Self‐Assembly into Rotator Phases 下载免费PDF全文
Dr. Hanumantha Rao Vutukuri Dr. Arnout Imhof Prof. Dr. Alfons van Blaaderen 《Angewandte Chemie (International ed. in English)》2014,53(50):13830-13834
Particle shape is a critical parameter that plays an important role in self‐assembly, for example, in designing targeted complex structures with desired properties. Over the last decades, an unprecedented range of monodisperse nanoparticle systems with control over the shape of the particles have become available. In contrast, the choice of micrometer‐sized colloidal building blocks of particles with flat facets, that is, particles with polygonal shapes, is significantly more limited. This can be attributed to the fact that in contrast to nanoparticles, the larger colloids are significantly harder to synthesize as single crystals. It is now shown that a very simple building block, such as a micrometer‐sized polymeric spherical colloidal particle, is already enough to fabricate particles with regularly placed flat facets, including completely polygonal shapes with sharp edges. As an illustration that the yields are high enough for further self‐assembly studies, the formation of three‐dimensional rotator phases of fluorescently labelled, micrometer‐sized, and charged rhombic dodecahedron particles was demonstrated. This method for fabricating polyhedral particles opens a new avenue for designing new materials. 相似文献
53.
Self‐Assembly: Self‐Organization of Anisotropic and Binary Colloids in Thermo‐Switchable 1D Microconfinement (Part. Part. Syst. Charact. 3/2015) 下载免费PDF全文
54.
Dr. Jules Tshishimbi Muya Dr. Erwin Lijnen Prof. Dr. Minh Tho Nguyen Prof. Dr. Arnout Ceulemans 《Chemphyschem》2013,14(2):346-363
Extensive optimisation calculations are performed for the B80 isomers in order to find out which principles underlie the formation of large hollow boron cages. Our analysis shows that the most stable isomers contain triangular B10 or rhombohedral B16 building blocks. The lowest‐energy isomer has C3v symmetry and is characterised by a belt of three interconnected B16 units and two separate B10 units. At the B3LYP/6‐31G(d) level of theory, this newly discovered isomer is 2.29, 1.48, and 0.54 eV below the leapfrog B80 of Szwacki et al., the Th‐B80 of Wang, and the D3d‐B80 of Pochet et al., respectively. Our C3v isomer is therefore identified as the most stable hollow cage isomer of B80 presently known. Its HOMO–LUMO gap of 1.6 eV approaches that of the leapfrog B80. The leapfrog principle still remains a reliable scheme for producing boron cages with larger HOMO–LUMO gaps, whereas the thermodynamically most stable B80 cages are formed when all pentagonal faces are capped. We show that large hollow cages of boron retain a preference for fullerene frames. The additional capping is in accordance with the following rules: preference for capping of pentagonal faces, formation of B10 and/or B16 units, homogeneous distribution of the hexagonal caps, and hole density approaching 1/9. Although our most stable B80 isomer still remains higher in energy than the B80 core–shell structure, we show that by applying the bonding principles to larger structures it is possible to construct boron cages with higher stabilisation energy per boron atom than the core–shell structure; a prototypical example is B160. This clearly shows the continuous competition between the two suggested construction schemes, namely, the formation of multiple‐shell structures and hollow cages. 相似文献
55.
A density functional theory study of small base molecules and tetrahedral and cubane-like group V clusters encapsulated in B(80) shows that the boron buckyball is a hard acid and prefers hard bases like NH(3) or N(2)H(4) to form stable off-centered complexes. In contrast, tetrahedral and cubane-like clusters of this family are metastable in the cage. The most favorable clusters are the mixed tetrahedral and cubane clusters formed by nitrogen and phosphorus atoms such as P(2)N(2)@B(80), P(3)N@B(80), and P(4)N(4)@B(80). The boron cap atoms are electrophilic centers, and prefer mainly to react with electron rich nucleophilic sites. The stability of the complexes will be governed by the size and electron donating character of the encapsulated clusters. B(80) forms stable complexes with hard materials where a bidentate interaction of the encapsulated molecule with two boron cap atoms is preferred over a single direct complex toward a single endohedral boron. 相似文献
56.
Amber Ronteltap Arnout R. H. Fischer Hilde Tobi 《Journal of nanoparticle research》2011,13(10):4399-4410
Nanotechnology is an emerging technology particularly vulnerable to societal unrest, which may hinder its further development.
With the increasing convergence of several technological domains in the field of nanotechnology, so too could convergence
of social science methods help to anticipate societal response. This paper systematically reviews the current state of convergence
in societal response research by first sketching the predominant approaches to previous new technologies, followed by an analysis
of current research into societal response to nanotechnology. A set of 107 papers on previous new technologies shows that
rational actor models have played an important role in the study of societal response to technology, in particular in the
field of information technology and the geographic region of Asia. Biotechnology and nuclear power have, in contrast, more
often been investigated through risk perception and other affective determinants, particularly in Europe and the USA. A set
of 42 papers on societal response to nanotechnology shows similarities to research in biotechnology, as it also builds on
affective variables such as risk perception. Although there is a tendency to extend the rational models with affective variables,
convergence in social science approaches to response to new technologies still has a long way to go. The challenge for researchers
of societal response to technologies is to converge to some shared principles by taking up the best parts from the rational
actor models dominant in information technology, whilst integrating non-rational constructs from biotechnology research. The
introduction of nanotechnology gives a unique opportunity to do so. 相似文献
57.
Intrinsic Folding Proclivities in Cyclic β‐Peptide Building Blocks: Configuration and Heteroatom Effects Analyzed by Conformer‐Selective Spectroscopy and Quantum Chemistry 下载免费PDF全文
Dr. Mohammad Alauddin Dr. Eric Gloaguen Dr. Valérie Brenner Benjamin Tardivel Dr. Michel Mons Dr. Anne Zehnacker‐Rentien Dr. Valérie Declerck Prof. David J. Aitken 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(46):16479-16493
This work describes the use of conformer‐selective laser spectroscopy following supersonic expansion to probe the local folding proclivities of four‐membered ring cyclic β‐amino acid building blocks. Emphasis is placed on stereochemical effects as well as on the structural changes induced by the replacement of a carbon atom of the cycle by a nitrogen atom. The amide A IR spectra are obtained and interpreted with the help of quantum chemistry structure calculations. Results provide evidence that the building block with a trans‐substituted cyclobutane ring has a predilection to form strong C8 hydrogen bonds. Nitrogen‐atom substitution in the ring induces the formation of the hydrazino turn, with a related but distinct hydrogen‐bonding network: the structure is best viewed as a bifurcated C8/C5 bond with the N heteroatom lone electron pair playing a significant acceptor role, which supports recent observations on the hydrazino turn structure in solution. Surprisingly, this study shows that the cis‐substituted cyclobutane ring derivative also gives rise predominantly to a C8 hydrogen bond, although weaker than in the two former cases, a feature that is not often encountered for this building block. 相似文献
58.
The 2-trimethylsilylethanesulfonyl (or SES) protecting group was compared to the tosyl (Ts) group in the preparation of a nitrogen-containing five-membered ring obtained by the aza-Baylis-Hillman/alkylation/RCM route. While deprotection of Ts-protected pyrrolines gave only pyrroles, deprotection of the same SES-protected compounds gave either pyrroles or free amine pyrrolines depending on the deprotection conditions. The SES-protected pyrrolines were hydrogenated to yield pyrrolidines with an excellent diastereoselectivity. Free amine pyrrolidines were obtained by HF-mediated deprotection of the SES group. 相似文献
59.