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Articles 1 - 13 of 13
Full-Text Articles in Entire DC Network
Metallomesogens: Supramolecular Design Via Alkyl-Rich Metal Complexes, Juan C. Noveron
Metallomesogens: Supramolecular Design Via Alkyl-Rich Metal Complexes, Juan C. Noveron
Juan C N
Molecules that use non-covalent interactions to self-organize into supramolecular structures have the potential to generate functional materials with a broad range of applications. This review article focuses on the design and synthesis of molecules that use transition metal ions and long alkyl chains to direct the formation of ordered supramolecular phases. This unique combination of coordination bonds and alkyl interdigitation provide exceptional control over intermolecular interactions and can generate nanoscale molecular order as liquid crystalline states, Langmuir-Blodgett films on surfaces, highly ordered lyotropic phases such as metallo-micelles in water and reverse metallo-micelles in organic media. The synthetic strategy for alkane-rich …
Emergence Of Nanodistricts In The United States: Path Dependency Or New Opportunities?, Philip Shapira, Jan Youtie
Emergence Of Nanodistricts In The United States: Path Dependency Or New Opportunities?, Philip Shapira, Jan Youtie
Philip Shapira
Multiple economic development theories suggest that research and innovation in emerging technologies will cluster in certain locations rather then distributing equally among all regions. If this is the case, this distributional pattern has implications for where future economic opportunities as well as future risks will be concentrated. In this paper, we probe nanotechnology (hereafter nano) research and commercialization at a regional level. The study examines the top 30 US “nanodistricts” or metropolitan areas which lead in nanotechnology research activity over the 1990-2006 timeframe. We explore the factors underlying the emergence of these 30 metropolitan areas through exploratory cluster analysis. We …
Refining Search Terms For Nanotechnology, Alan L. Porter, Jan Youtie, Philip Shapira, David J. Schoeneck
Refining Search Terms For Nanotechnology, Alan L. Porter, Jan Youtie, Philip Shapira, David J. Schoeneck
Philip Shapira
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. …
The Technology Of Law And Economics, John H. Moran
The Technology Of Law And Economics, John H. Moran
John H Moran
The article suggests that the field of Technology drives the fields of Economics and Law. It relies on Richard Posner's law and economics ideas, but also argues that technologists have increasing influence on the emerging world order, to the detriment of the existing government and banking based power structure.
Biomimic Fabrication Of Electrospun Nanofibers With High-Throughput, Ji-Huan He, Yong Liu, Lan Xu, Jian-Yong Yu, Gang Sun
Biomimic Fabrication Of Electrospun Nanofibers With High-Throughput, Ji-Huan He, Yong Liu, Lan Xu, Jian-Yong Yu, Gang Sun
Ji-Huan He
Spider-spun fiber is of extraordinary strength and toughness comparable to those of electrospun fiber, the later needs a very high voltage (from several thousands voltage to several ten thousands voltages) applied to water-soluble protein “soup” that was produced by a spider, furthermore, its mechanical strength dramatically decreases comparable to spider silk. A possible mechanism in spider-spinning process is given, the distinct character in spider-spinning is that its spinneret consists of millions of nano scale tubes, and a bubble can be produced at the apex of each nano-tube. The surface tension of each bubble is extremely small such that it can …
Effect Of Concentration On Electrospun Polyacrylonitrile (Pan) Nanofibers, Ji-Huan He, Yu-Qin Wan, Jian-Yong Yu
Effect Of Concentration On Electrospun Polyacrylonitrile (Pan) Nanofibers, Ji-Huan He, Yu-Qin Wan, Jian-Yong Yu
Ji-Huan He
Abstract: An allometrical scaling relationship between the diameter of electrospun nanofiber and solution concentration is established, the scaling exponent differs greatly between different polymers and the same polymer with different molecules or the same molecules with different properties. The diameter of electrospun polyacrylonitrile (PAN) nanofibers increases approximately linearly with solution concentration.
Controlling Numbers And Sizes Of Beads In Electrospun Nanofibers, Yong Liu, Ji-Huan He, Jian-Yong Yu, Hong-Mei Zeng
Controlling Numbers And Sizes Of Beads In Electrospun Nanofibers, Yong Liu, Ji-Huan He, Jian-Yong Yu, Hong-Mei Zeng
Ji-Huan He
Abstract BACKGROUND: Electrospinning is a powerful and effective method to produce nanofibers. Beads have been observed widely in electrospun products, but effects of solvents, weight concentrations and salt additives on the number and morphology of beads in the electrospinning process have not been systematically studied. RESULTS: Both theoretical analysis and experimental results show that beads strongly depend upon solvents, weight concentrations and salt additives. Either a suitable weight concentration or a suitable salt additive can completely prevent the occurrence of beads in the electrospinning process; solvents can affect the number of beads and the morphology of electrospun fibers. CONCLUSION: Beads …
A New Resistance Formulation For Carbon Nanotubes, Ji-Huan He
A New Resistance Formulation For Carbon Nanotubes, Ji-Huan He
Ji-Huan He
A new resistance formulation for carbon nanotubes is suggested using fractal approach. The new formulation is also valid for other nonmetal conductors including nerve fibers, conductive polymers, and molecular wires. Our theoretical prediction agrees well with experimental observation.
Non-Ionic Surfactants For Enhancing Electrospinability And For The Preparation Of Electrospun Nanofibers, Shu-Qiang Wang, Ji-Huan He, Lan Xu
Non-Ionic Surfactants For Enhancing Electrospinability And For The Preparation Of Electrospun Nanofibers, Shu-Qiang Wang, Ji-Huan He, Lan Xu
Ji-Huan He
Abstract BACKGROUND: Electrospinning is widely used to produce nanofibers; however, not every polymer can be electrospun into nanofibers. To enhance electrospinability, much effort has been made in designing new apparatus, such as vibration-electrospinning, magneto-electrospinning and bubble-electrospinning. RESULTS: A representative non-ionic surfactant, TritonR X-100, is used to enhance electrospinability. The surfactant is added to an electrospun poly(vinyl pyrrolidone) polymer solution, and a dramatic reduction in surface tension is observed. As a result, a moderate voltage is needed to produce fine nanofibers, which are commonly observed during the conventional electrospinning procedure only at elevated voltage. CONCLUSION: The novel strategy produces smaller nanofibers …
Nanocomposite Powders For New Contact Materials Based On Copper And Alumina, Zeljko J. Kamberovic
Nanocomposite Powders For New Contact Materials Based On Copper And Alumina, Zeljko J. Kamberovic
Zeljko J Kamberovic
This paper is a contribution to characterization of Cu-Al2O3 powders with nanostructure designed for the production of dispersion strengthened contact materials. New materials with predetermined properties can be successfully synthesized by utilizing the principles of hydrometallurgy and powder metallurgy. The results show a development of a new procedure for the synthesis. The applied characterization methods were differential thermal and thermogravimetric analysis (DTA-TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM): Focused Ion Beam (FIB) and Analytical Electron Microscopy (AEM). Nanostructure characteristics, particle size in range 20-50 nm, and uniform distribution of dispersoide in copper matrix were validated.
Determination Of Al2o3 Particle Size In Cu-Al2o3 Nanocomposite Materials Using Uv Spectrophotometry, Zeljko J. Kamberovic
Determination Of Al2o3 Particle Size In Cu-Al2o3 Nanocomposite Materials Using Uv Spectrophotometry, Zeljko J. Kamberovic
Zeljko J Kamberovic
In order to achieve improved mechanical properties of dispersion strengthened nanocomposite, without influencing electrical and thermal conductivity it is necessary for dispersoide to be nano sized and uniformly distributed in base metal matrix. In this paper are presented the results concerning possibility of using UV spectrophotometry for determination of alumina particle size in Cu-Al2O3 system. Presented results show that this method is unefficient as method for determination of dispersoide particle size, due to the coalescence of particles false results are obtained, i.e. particle size significantly higher then one determined by image analysis.
Foreword, Michele L. Mekel
Foreword, Michele L. Mekel
Michele L Mekel
Foreword for the book "Nanotechnology, Ethics, and Society"
Electrospinning: A Promising Technology For Discontinuous And Continuous Nanofibers, Ji-Huan He
Electrospinning: A Promising Technology For Discontinuous And Continuous Nanofibers, Ji-Huan He
Ji-Huan He
No abstract provided.