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1.
While several studies on the public opinion of nanotechnology have pointed to a rather enthusiastic U.S. public, the public
uptake of nanotechnology in Europe is more contained. The results of the Swiss publifocus on nanotechnology reveal a pragmatic attitude of citizens toward the emerging technologies, thus confirming what has been
identified as a “balanced approach” in the NanoJury UK.
相似文献
Regula Valérie BurriEmail: |
2.
The seminal paper by Ya. B. Zeldovich (Soviet Physics Uspekhi 11, 381–393, 1968) is reprinted here, together with an editorial comment on its lasting scientific relevance, and a biography
of the author.
相似文献
Andrzej KrasińskiEmail: |
3.
Refining search terms for nanotechnology 总被引:5,自引:3,他引:2
Alan L. Porter Jan Youtie Philip Shapira David J. Schoeneck 《Journal of nanoparticle research》2008,10(5):715-728
The ability to delineate the boundaries of an emerging technology is central to obtaining an understanding of the technology’s
research paths and commercialization prospects. Nowhere is this more relevant than in the case of nanotechnology (hereafter
identified as “nano”) given its current rapid growth and multidisciplinary nature. (Under the rubric of nanotechnology, we
also include nanoscience and nanoengineering.) Past efforts have utilized several strategies, including simple term search
for the prefix nano, complex lexical and citation-based approaches, and bootstrapping techniques. This research introduces
a modularized Boolean approach to defining nanotechnology which has been applied to several research and patenting databases.
We explain our approach to downloading and cleaning data, and report initial results. Comparisons of this approach with other
nanotechnology search formulations are presented. Implications for search strategy development and profiling of the nanotechnology
field are discussed.
相似文献
Jan YoutieEmail: |
4.
Expert opinion on nanotechnology: risks,benefits, and regulation 总被引:2,自引:2,他引:0
John C. Besley Victoria L. Kramer Susanna H. Priest 《Journal of nanoparticle research》2008,10(4):549-558
A survey of American (US) nanotechnology researchers (N = 177) suggests a diversity of views about what areas are most important to the burgeoning field, as well as perceptions about
the overall benefits and risks of such research. On average, respondents saw a range of technologies as key and viewed public
health and environmental issues as areas where both risks and the need for regulation are greatest. These areas were also
where respondents said current regulations were least adequate. Factor analyses of the survey questions suggest that, when
considering both risks and regulations, respondents make a distinction between health and environmental risks, and what might
be termed “social risks” (e.g., invasion of privacy, use of nanotechnology in weapons, and economic impacts).
相似文献
John C. BesleyEmail: |
5.
Joseph S. Gardner Endrit Shurdha Chongmin Wang Lisa D. Lau René G. Rodriguez Joshua J. Pak 《Journal of nanoparticle research》2008,10(4):633-641
The properties of CuInS2 semi-conductor nanoparticles make them attractive materials for use in next-generation photovoltaics. We have prepared CuInS2 nanoparticles from single source precursors via microwave irradiation. Microwave irradiation methods have allowed us to increase
the efficiency of preparation of these materials by providing uniform heating and rapid reaction times. The synergistic effect
of varying thiol capping ligand concentrations as well as reaction temperatures and times resulted in fine control of nanoparticle
growth in the 3–5 nm size range. Investigation of the photophysical properties of the colloidal nanoparticles were performed
using electronic absorption and luminescence emission spectroscopy. Qualitative nanoparticles sizes were determined from the
photoluminescence (PLE) data and compared to HRTEM images.
相似文献
Joshua J. PakEmail: |
6.
An overview of the special issue of the Journal of Nanoparticle Research on Occupational and Environmental Health of nanotechnology
is presented. Papers published in this special issue show considerable progress in understanding nanoparticle toxicity, monitoring,
generation, dustiness, filtration, and applications of nanoparticles. More research is needed to ensure safe handling of nanomaterials
as nanotechnology continues to develop at an incredible pace.
相似文献
Chuen-Jinn TsaiEmail: |
7.
Graphs of the total radius (the distance between an anionic nuclei and a cationic nuclei in a crystal) of sodium halides and
alkali metal fluorides versus total limiting equivalent conductivities were plotted. For the hard ions Na+ and F−, whose behaviour approaches a hard spherical model, it was determined that radii values could be obtained using differences
in limiting equivalent conductivities and ionic crystal data. From the determined radii of sodium and fluoride ions and known
crystal data, radii of other alkali metal halides were calculated.
相似文献
Sevda AyataEmail: |
8.
To understand and engineer applications for mixed conducting oxides, it is desirable to have explicit, analytical expressions
for the functional dependence of defect concentration and transport properties on the partial pressure of the external gas
phase. To fulfill this need, general expressions are derived for the functional dependence of defect concentration on the
oxygen partial pressure () for the mixed ionic electronic conductors. The model presented in this paper differs from expressions obtained using the
popular Brouwer approach because they are continuous across multiple Brouwer regions.
相似文献
Eric D. WachsmanEmail: |
9.
L. P. Kamburov H. D. Hristov J. R. Urumov R. Feick 《International Journal of Infrared and Millimeter Waves》2005,26(11):1593-1611
A generalized vector diffraction theory of the half-open curvilinear Fresnel zone plate (FZP) tens antenna that is valid for
any lens profile shape is presented. It is an extension to the vector Kirchhoff diffraction theory for the plane half-open
FZP lens antenna and is based on the conical-segment lens profile approximation. An equation for the electric far-field vector
is derived from which follow the expressions for the co- and cross-polarization radiation patterns and directive gain. The
proposed theory is utilized for a numerical analysis and comparison of 140-GHz curvilinear half-open FZP lens antennas grouped
in two distinct sets:
相似文献
(a) | Set I: antennas with different in shape FZP lenses (plane, conical, parabolic and spherical) having the same number of zones. All eurvilinear FZP antenna lenses are designed for similar gain, co- and cross-polarization performance and bandwidth, regardless of the lens-profile. |
(b) | Set II: antennas with different in shape FZP lenses and different number of zones. Since this affects gain, polarization and bandwidth performance, to make the characteristics of these FZP lens antennas practically equal to those of Set I, antenna feeds with different gain patterns have been used. |
10.
Using the total radius of alkaline fluorides and sodium halides and their experimental total enthalpy values, absolute hydration
enthalpies of sodium and fluoride ions ( and ) were previously calculated. Also, by the help of data of sodium and fluoride ions for all alkaline metal ions and halides
absolute hydration enthalpies were determined.
相似文献
Sevda AyataEmail: |
11.
As technology has evolved available guidelines for normal-phase flash chromatography have become less relevant. Years of experience
performing chromatography with disposable columns have been condensed into simple guidelines useful for translating TLC results
into either isocratic- or gradient-flash chromatography. The described studies should provide researchers with a means of
selecting adequate columns and guidelines to reduce the waste of solvents, silica, time, and money.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
William C. Stevens Jr.Email: |
12.
Facilitating cross-disciplinary research has attracted much attention in recent years, with special concerns in nanoscience
and nanotechnology. Although policy discourse has emphasized that nanotechnology is substantively integrative, some analysts
have countered that it is really a loose amalgam of relatively traditional pockets of physics, chemistry, and other disciplines
that interrelate only weakly. We are developing empirical measures to gauge and visualize the extent and nature of interdisciplinary
interchange. Such results speak to research organization, funding, and mechanisms to bolster knowledge transfer. In this study,
we address the nature of cross-disciplinary linkages using “science overlay maps” of articles, and their references, that
have been categorized into subject categories. We find signs that the rate of increase in nano research is slowing, and that
its composition is changing (for one, increasing chemistry-related activity). Our results suggest that nanotechnology research
encompasses multiple disciplines that draw knowledge from disciplinarily diverse knowledge sources. Nano research is highly,
and increasingly, integrative—but so is much of science these days. Tabulating and mapping nano research activity show a dominant
core in materials sciences, broadly defined. Additional analyses and maps show that nano research draws extensively upon knowledge
presented in other areas; it is not constricted within narrow silos.
相似文献
Jan YoutieEmail: |
13.
Dong Li 《Journal of statistical physics》2007,129(2):265-287
It has been shown in E and Li (Comm. Pure. Appl. Math., 2007, in press) that the Andersen dynamics is uniformly ergodic. Exponential convergence to the invariant measure is established
with an error bound of the form
where N is the number of particles, ν is the collision frequency and κ(ν)→const as ν→0. In this article we study the dependence on ν of the rate of convergence to equilibrium. In the one dimension and one particle case, we improve the error bound to be
In the d-dimension N-particle free-streaming case, it is proved that the optimal error bound is
It is also shown that as ν→∞, on the diffusive time scale, the Andersen dynamics converges to a Smoluchowski equation. 相似文献
14.
The effect of co-doping yttria-stabilised zirconia with calcia and scandia has been investigated. Changes in the yttrium ion
local environment have been monitored using solid-state magic angle sample spinning 89Y nuclear magnetic resonance. The effect on the low-temperature (below 320 °C) bulk ionic conductivity has been observed using
AC impedance spectroscopy. It was found that the number of oxygen vacancies in the nearest-neighbour sites to yttrium ions
decreased on co-doping with scandia, correlating with an increase in conductivity, but increased on co-doping with calcia,
correlating with a decrease in conductivity. This behaviour can be explained by proposing the trapping of oxygen vacancies
in the nearest-neighbour yttrium ion sites so that they no longer contribute to the conduction mechanism.
相似文献
R. J. DarbyEmail: |
15.
Dhimiter Bello Brian L. Wardle Namiko Yamamoto Roberto Guzman deVilloria Enrique J. Garcia Anastasios J. Hart Kwangseog Ahn Michael J. Ellenbecker Marilyn Hallock 《Journal of nanoparticle research》2009,11(1):231-249
This study investigated airborne exposures to nanoscale particles and fibers generated during dry and wet abrasive machining
of two three-phase advanced composite systems containing carbon nanotubes (CNTs), micron-diameter continuous fibers (carbon
or alumina), and thermoset polymer matrices. Exposures were evaluated with a suite of complementary instruments, including
real-time particle number concentration and size distribution (0.005–20 μm), electron microscopy, and integrated sampling
for fibers and respirable particulate at the source and breathing zone of the operator. Wet cutting, the usual procedure for
such composites, did not produce exposures significantly different than background whereas dry cutting, without any emissions
controls, provided a worst-case exposure and this article focuses here. Overall particle release levels, peaks in the size
distribution of the particles, and surface area of released particles (including size distribution) were not significantly
different for composites with and without CNTs. The majority of released particle surface area originated from the respirable
(1–10 μm) fraction, whereas the nano fraction contributed ~10% of the surface area. CNTs, either individual or in bundles,
were not observed in extensive electron microscopy of collected samples. The mean number concentration of peaks for dry cutting
was composite dependent and varied over an order of magnitude with highest values for thicker laminates at the source being
>1 × 106 particles cm−3. Concentration of respirable fibers for dry cutting at the source ranged from 2 to 4 fibers cm−3 depending on the composite type. Further investigation is required and underway to determine the effects of various exposure
determinants, such as specimen and tool geometry, on particle release and effectiveness of controls.
相似文献
Dhimiter BelloEmail: |
16.
Alexis D. Ostrowski Tyronne Martin Joseph Conti Indy Hurt Barbara Herr Harthorn 《Journal of nanoparticle research》2009,11(2):251-257
Understanding the toxicity of nanomaterials and nano-enabled products is important for human and environmental health and
safety as well as public acceptance. Assessing the state of knowledge about nanotoxicology is an important step in promoting
comprehensive understanding of the health and environmental implications of these new materials. To this end, we employed
bibliometric techniques to characterize the prevalence and distribution of the current scientific literature. We found that
the nano-toxicological literature is dispersed across a range of disciplines and sub-fields; focused on in vitro testing;
often does not specify an exposure pathway; and tends to emphasize acute toxicity and mortality rather than chronic exposure
and morbidity. Finally, there is very little research on consumer products, particularly on their environmental fate, and
most research is on the toxicity of basic nanomaterials. The implications for toxicologists, regulators and social scientists
studying nanotechnology and society are discussed.
相似文献
Barbara Herr HarthornEmail: |
17.
Farruggia G Iotti S Prodi L Zaccheroni N Montalti M Savage PB Andreani G Trapani V Wolf FI 《Journal of fluorescence》2009,19(1):11-19
The intracellular behaviour of diaza-18-crown-6 appended with two H-substituted hydroxyquinoline groups (DCHQ1) was investigated
to explore its application as a new sensor for the evaluation of cell magnesium content and distribution. We used five cells
lines characterised by different contents of magnesium and different intracellular membrane-defined compartments. The main
result is the definition of the appropriate experimental conditions to quantitatively assess the total cell magnesium by fluorescence
spectroscopy. We showed that disrupting cells by sonication, DCHQ1 was capable to assess total cell magnesium in all cell
types examined, obtaining overlapping results with atomic absorption spectroscopy (AAS). This new analytical approach requires
very small cell samples and a simple fluorimetric technique, and can be a valid alternative to AAS. The fluorescent properties
of DCHQ1 in living cells are: (a) it consistently stains live cells, (b) it discriminates small variations of cell Mg contents,
(c) cell staining is stable for at least 30 min. We also investigated the role of lipophilic environment on DCHQ1 fluorescence
by mimicking cell membranes and described how the composition and structure of lipid vesicles affect Mg-DCHQ1 fluorescence.
Thus, DCHQ1 may offer important information also on magnesium distribution in living cells, providing a novel strategy to
map the intracellular compartmentalization of this cation.
相似文献
Federica I. Wolf (Corresponding author)Email: |
18.
M. Malinowski R. Wolski Z. Frukacz T. Lukasiewicz Z. Luczynski 《Journal of Applied Spectroscopy》1995,62(5):840-843
Optical properties of the Sm3+ ion in YAG crystals have been investigated, in particular:
The relatively large emission cross section and long fluorescence lifetime enable red laser action to be obtained. 相似文献
– | - the energy level diagram of Sm:YAG has been established. |
– | - the emission characteristics of the metastable state4G5/2 have been determined. |
– | - the oscillator strengths of various Sm transitions have been investigated using the Judd-Ofelt theory. |
19.
Oded Schramm Scott Sheffield David B. Wilson 《Communications in Mathematical Physics》2009,288(1):43-53
The conformal loop ensembles CLE
κ
, defined for 8/3 ≤ κ ≤ 8, are random collections of loops in a planar domain which are conjectured scaling limits of the O(n) loop models. We calculate the distribution of the conformal radii of the nested loops surrounding a deterministic point.
Our results agree with predictions made by Cardy and Ziff and by Kenyon and Wilson for the O(n) model. We also compute the expectation dimension of the CLE
κ
gasket, which consists of points not surrounded by any loop, to be
, which agrees with the fractal dimension given by Duplantier for the O(n) model gasket.
Partially supported by NSF grant DMS0403182. 相似文献
20.
Frequency domain (FD) fluorescence lifetime data was collected for a series of 20 crude petroleum oils using a 405 nm excitation
source and over a spectral range of ~426 to ~650 nm. Average fluorescence lifetimes were calculated using three different
models: discrete multi-exponential, Gaussian distribution, and Lorentzian distribution. Fitting the data to extract accurate
average lifetimes using the various models proved easier and less time consuming for the FD data than with Time Correlated
Single Photon Counting (TCSPC) methods however the analysis of confidence intervals to the computed average lifetimes proved
cumbersome for both methods. The uncertainty in the average lifetime was generally larger for the discrete lifetime multi-exponential
model when compared to the distribution-based models. For the lifetime distributions, the data from the light crude oils with
long lifetimes generally fit to a single decay term. Heavier oils with shorter lifetimes required multiple decay terms. The
actual value for the average lifetime is more dependant on the specific fitting model employed than the data acquisition method
used. Correlations between average fluorescence lifetimes and physical and chemical parameters of the crude oils were made
with a view to developing a quantitative model for predicting the gross chemical composition of crude oils. It was found that
there was no significant benefit gained by using FD over TCSPC other than more rapid data analysis in the FD case. For the
FD data the Gaussian distribution model for fluorescence lifetime gave the best correlations with chemical composition allowing
a qualitative correlation to some bulk oil parameters.
相似文献
Alan G. RyderEmail: |