SPM equipment

The STM AFM unit (Unversial SPC 400 SPM, Park Scifentific Instruments) consisted of an electronic unit which provided both the scan control for scanning the tip over the surface and an electronic feedback loop maintaining a constant working distance between tip sample. Additionally a four-electrode bi-potentiostat that was connected to the control unit was capable of setting the potentials of both tip and substrate independently. This system allowed minimization of the electrochemical current...

Characteristics and Applications of Hybrimers

Based on the above synthesis schemes, numerous hybrimers have been developed in recent years. This development yields many interesting new materials, with improved mechanical properties tunable between those of glasses and those of polymers, with improved optical properties (efficiency, stability, new functions, etc) and with improved catalytic or membrane based properties 60-62, 105-109, 119, 123, 124 . Due to the nano-scale structure and processing, the hybrimers are transparent amorphous...

Reduction of Minerals The Case of Bastnaesite

A nonthermal process for extracting rare earths from bast-naesite by means of mechanochemical treatment has been developed by Zhang and Saito 302 . Bastnaesite (ReCO3F, Re rare earths) is one of the most important resources containing rare earth elements such as La and Ce. There are several hydrometallurgical methods for extracting them from bastnaesite. They can be classified into two process methodologies one is the acidic method using H2SO4 solution the other the alkali method using NaOH. In...

Mechanical Deagglomeration

Intimate contacts (up to almost the molecular level) of the nanoparticles with the polymeric matrix are a prerequisite for the design of well-functioning nanocomposites. To satisfy this condition, a thorough homogenization of the components must be obtained. Winkler et al. 125 developed a theory for the deagglomeration of ultrafine particle clusters in fluid systems, using the mechanical forces in a dispersion machinery. They showed that the probability that filler particles are dispersed in a...

MEMS Technology for Military Systems Applications

RF-MEMS and optical-MEMS devices can play key roles in the design and development of military sensors to meet specific mission requirements. Because of their low-power consumption, compact size, and ultrahigh reliability, MEMS are most suitable in development of sensors for battlefield tanks, surveillance for hostile territory, drone electronics, covert communications, unmanned air vehicles (UAVs), and missiles to shoot down hostile targets. The success of future battlefield conflicts is...

Key Factors of an Ideal Bone Graft

Although most of the synthetic grafts available possess favorable characteristics for bone regeneration currently none resembles autogenic bone, which further stimulates research in bone grafting. It is worthwhile to recall that reconstruction of bone tissue by synthetic bone grafts having structure, composition, and biological features that mimic natural bone tissue is the ultimate goal to be pursued for any bone grafting. Therefore, engineering a bone graft with these features is a real...

Self Driven Methods for Movement

Surface Energy Driven Phenomena. Camphor boats at the water-air interface were one of the first well-studied systems that move autonomously.5 The motion of a camphor boat is accredited to the dissolution of camphor which lowers the interfacial tension of the surrounding water and moves the object until it is completely dissolved. Interfacial tension gradients are not exclusive to camphor boats in water. Another system where interfacial tension gradients are responsible for the...

Seeking Venture Capital

To obtain venture capital, a nanotech start-up must have a viable strategy, pro-tectable intellectual property (IP), and a strong business plan. We discussed these issues in the first two chapters of this section. We now describe the process of pursuing venture capital, from getting an initial meeting to negotiating a Letter of Intent. The first major issue in nanotech fundraising is networking and leveraging a group of personal connections and contacts. During the Internet boom, entrepreneurs...

Structure and Dispersion of CNTs

Structurally, CNTs can be approximated as ''rolled-up'' sheets of graphite (Fig.1). In this graphite, sp2 hybridization occurs, where each carbon atom is connected evenly to other three carbon atoms (120 ) in the xy plane, and a weak n bond is present in the z axis. The sp2 set forms the hexagonal (honeycomb) lattice of a sheet of graphite Dresselhaus et al. 2000, Odom et al. 2000, Terrones 2003 . Varieties of CNTs include single-walled nanotubes (SWNTs) and multi-walled nanotubes (MWNTs)....

The Consumer Product Safety Commission Cpsc

Despite the reportedly growing number of consumer products enabled by nanotech-nology, the Consumer Product Safety Commission (CPSC) has been relatively inactive, at least publicly, on nanotechnology matters . The CPSC is a member of the NNI but has yet to develop any public guidance or other documents with the exception of the CPSC's 2005 issuance of its Nanomaterial Statement 52 . According to the CPSC, the introduction of consumer products containing nano-materials into the marketplace may...

Bonding of Gold Nanoparticles on TiO2110 in Different Oxidation States

Transition-metal nanoparticles are interesting from the perspective of both fundamental studies and applications, and in recent years specifically gold (Au) nanoparticles have attracted great attention. The main reason for this is the surprising catalytic activity of small Au nanoparticles dispersed on oxide supports for numerous reactions 97 102 , but other potential uses, such as in photocatalysis 3,103 110 and solar energy conversion 111,112 have also triggered intense research activity into...

Structure of PPVBased Systems

Based on molecular mechanics energy minimization in a vacuum, a single MEH-PPV or CN-PPV molecule containing tetrahedral defects has a lower total potential energy when folded into cofacial-stacked chain segments (see Figure 14.5) than in an extended chain configuration on the order of tens of kcal mol determined from the MM3 model for the all trans-anti-configuration. For MEH-PPV, an all trans-syn-configuration lies at 3 kcal mol higher in potential energy than the anti'-configuration due to...

Properties of layered silicate polypropylene nanocomposites

Nanoparticles are able to provide PP with stiffening, reinforcing and toughening effects at rather low filler concentration. The influence of processing conditions on the nanocomposite structure, i.e. intercalated or exfoliated, and on the enhancement of mechanical properties of PP nanocomposites was studied by different researchers.44 Most polymer clay nanocomposites studies report tensile properties as a function of MMT content.19 The enhancements are strictly related to the processing...

Synthesis and Tribological Behavior of Silicon Oxycarbonitride Thin Films Derived from Poly Urea Methyl Vinyl Silazane

University of Colorado at Boulder, Department of Mechanical Engineering, Boulder, Colorado 80309 Tsali J. Cross, Somuri V. Prasad, and David R. Tallant Sandia National Laboratories* Materials and Process Sciences Center, Albuquerque, New Mexico 87185 A process for deposition of silicon oxycarbonitride films from poly(urea)methyl vinyl silazane (PUMVS) by spin coating precursor solutions onto a substrate, followed by polymerization, cross-linking and pyrolysis has been developed. The...

Rotaxanes

Several different schemes have now been reported for producing a rotaxane that undergoes shuttling action in response to an external stimulus. In 1991 one of the first functional molecular shuttles produced in reasonable yields was reported by Anelli and co-workers 11 . It is a 2 rotax-ane containing a linear dumbbell-shaped component, possessing two w-electron rich hydroquinone rings separated by a polyether chain, and terminated by two bulky triisopropy-lsilyl groups as stoppers. A cyclic...

Sashiro Uemura

Ise Electronics Corp., Tsumura, Ise, Mie, Japan An excellent performance of carbon nanotubes as field-emitters was demonstrated using a high-voltage FED (field emission display) elements at SID (Society for Information Display) in 1998, where a light-source tube for an outdoor large-size display and diodetype flat panel were presented with a screen-printed nanotube cathode 1 . The diode FED-panel image was presented by Samsung at SID in 1999 2 . After that, a triode structure that describes an...

Ending the Era of the Internal Combustion Engine

When American troops entered Munich in March 1945, one of the first companies to be seized was Varta, the large battery manufacturer. The company was the manufacturer of batteries and accumulators for the Wehrmacht submarines and for the Luftwaffe during World War II 1 . It is batteries that enable storage and thus the portability of electric power and since electricity is the most useful form of energy available to power technology devices, be they radios or noise .less submarine engines,...

Linear Polymer Chain Containing 250monomeric

Here X and Y refer to different monomers. Block copolymers consist of interconnected homopolymer chains, such as (-X4Y3-)n shown in Fig. 10.24. Graft copolymers, on the other hand, often exhibit homopolymer side chains. The proclivity for C60 to form free radicals and react with various reagents, as already described throughout this chapter, indicates that the incorporation of C60 into a polymer structure should be possible. This incorporation might be accomplished in one of...

Plasticity of Nanocrystalline Materials

Plasticity of nanocrystalline materials is of interest from both theoretical and practical points of view. The practical aspects are related both to the ease of producing complicated forms by plastic deformation as well as to the service performance of these materials. As discussed in the previous section, the susceptibility of, for example, fine-grained ECA pressed materials to strain localization limits their tensile and fatigue ductility and in practice to a large extent determines their...

Transient Absorption Spectroscopy

The development of transient absorption spectroscopy driven by the improvement in highpower pulsed-laser systems has allowed time-resolved observation of physical and chemical reactions, since the technique of flash photolysis was introduced by Professor George Porter in the 1950s 39 . The principle of submicrosecond to millisecond transient absorption spectroscopy is that a sample is irradiated with a short, intense laser pulse known as a pump pulse, and then resultant changes in the optical...

Wideangle Xray diffraction

A Bruker AXS wide-angle X-ray diffractometer with a Cu Ka average source (A 1.5418A) was utilized to look at the crystalline structure of the overall composite sample and to calculate the Herman orientation factor. The samples were run in transmission and reflection modes. In the reflection mode, the 8.4 SEM images of 3 wt MWNT in PP (a) unoriented, (b) oriented, 12 1 draw ratio. 8.4 SEM images of 3 wt MWNT in PP (a) unoriented, (b) oriented, 12 1 draw ratio. fibers were mounted on a 1 cm x 1...

Arrays of optical traps

A sophisticated scheme of interfering focused laser light beams has allowed creation and manipulation of 3D optically trapped structures 35 . Figure 3.13 schematically shows the nature of this optical trap and some of the configurations of dielectric spheres that have been stabilized. In Fig 3.13 (A) a detail schematic of the waist of the four-fold beam, which is shown stabilizing an array of eight dielectric spheres. (B) shows six other arrangements of identical dielectric spheres which were...

Sources of Warpage in Microchannel Arrays

Several sources have been identified for causing warpage within microchannel arrays. As shown above, one source of microchannel warpage can be the application of bonding pressure on regions of external laminae adjacent to microchannel regions. Another noted source of warpage can come directly from warpage in the raw shimstock, foil or film. Out of the box, even annealed, cold-rolled shimstock can have flatnesses greater than 50 pm on a 50 pm thick foil (Wattanutchariya and Paul 2004)....

Carbon Onions and Related Materials

After having made the acquaintance of fullerenes and of single- and multiwalled carbon nanotubes, the question arises on the existence of multiwalled fullerenes. Such carbon cages concentrically arranged one inside another are also called carbon onions. In comparison to other new carbon materials, they have by far been studied less. Chiefly this is because only small amounts of those are available. Still they represent an interesting structural variant of carbon. This chapter deals with their...

Reading Materials

Nanosystems Molecular Machinery, Manufacturing, and Computation. New York John Wiley & Sons, 1992. Fritz, Sandy. Understanding Nanotechnology From the Editors of Scientific American. New York Warner Books, 2002. Hall, J. Storrs. Nanofuture What's Next For Nanotechnology. Amherst, NY Prometheus Books, 2005. Newton, David E. Recent Advances and Issues in Molecular Nanotechnology. Westport, CT Greenwood Press, 2002. Scientific American (authors). Key Technologies for the 21st...

New Generation of Nanotools

Nanotechnology has triggered a revolution in many important areas in molecular biology and medicine, especially in the detection and manipulation of biological species at the molecular and cellular levels. The convergence of nanotechnology, molecular biology, and medicine will open new possibilities for detecting and manipulating atoms and molecules using nanodevices, with the potential for a wide variety of medical applications at the cellular level. Today, the amount of research in biomedical...

Tensile and Compressive Response Ductility and Creep Superplasticity

Again, the starting point in the discussion of these properties is the already well-known strong effect that grain size has on the ductility and toughness of conventional grain-size (> 1 m) materials. For example, the ductile-brittle transition temperature in conventional mild steel can be lowered by about 40 C by reducing the grain size by a factor of 5. We here recall that the brittleness can be defined in terms of the strain-rate sensitivity m, that is, the exponent in the equation and can...

Potential Comb Finger Shapes

Comb drive actuation is the major building block for MEMS devices requiring vertical, lateral, or rectangular displacement. Its operating principle is based on the ES force, which is generated between the interdigital conducting comb fingers of specific shapes as illustrated in Figure 3.20. Potential applications of shaped comb fingers include polysilicon microgrippers, sensing probe devices, forced-balanced accelerometers, actuation mechanism for rotating devices, and RF filters. The most...

Soft XRay Spectroscopy

5.2.1 Soft X-Ray Absorption and Emission Spectroscopy Soft X-ray absorption spectra provide information about the unoccupied states. For example, in oxygen K-edge absorption, the oxygen 1s electron is excited to empty electronic states in the carbon allotrope conduction band, and the dipole selection rule provides a tool to study locally the O2p character of these unoccupied valence bands (Figure 5.1). The atomic nature of the core hole implies elemental and site selectivity. The probability of...

Structure And Morphology

Control over structural and morphological properties are most crucial for performance of MMO nanoparticles in various applications. Mixed metal oxides are known to have different structural arrangement of constituent ions. The nature of these ions is important (size and charge) in the final adaptation of geometry however, control over homogeneity, stoichiometry, phase, and crystallinity largely depend upon structure and reactivity of precursors in homogeneous solutions and their fate in...

Physical Properties of TiO2 Nanotube Arrays

Physico-chemical properties of TiO2 nanotube arrays are very close to the properties of TiO2 nanoparticles, due to chemical and structural similarities. However, some unusual behaviour of nanotube arrays is observed, resulting from the specific nanotubular morphology of materials, and is considered in this section. Figure 3.18 shows the typical transmittance spectra of a 400 nm thick TiO2 nanotube array film on glass substrate.83 The optical behaviour of the TiO2 nanotube array is quite similar...

Escape Time of Electrons from Localized States

As we have seen in most approaches of the tunnelling time problem, only the scattering configuration in which the free electron (or wavepacket) is coming from the left (right) on a 1D arbitrary potential barrier has been considered. More than one tunnelling time is involved in this time problem, no matter whether we deal with the Buttiker-Landauer tbl or complex t t1 it2 characteristic times (see Eqs. (12) and (24)). Furthermore, this seems not to be a peculiarity of a quantum-mechanical wave,...

Scaling Relations Illustrated by a Simple Harmonic Oscillator

Consider a simple harmonic oscillator (SHO) such as a mass on a spring, as described above, and imagine shrinking the system in three dimensions. As stated, mal3and KaL, so a) (K m)y2al1. It is easy to see that the spring constant scales as I if the spring is taken a (massless) rod of cross section A and length I described by Young's modulus Y (F A)I(AL L). Under a compressive force F, AL -(LY A)F, so that the spring constant K LY A , aL. A more detailed analysis of the familiar coiled spring...

Should Government Fund Nanotechnology

Before analyzing how the National Nanotechnology Initiative is being implemented, one should consider whether government funding of nanotechnology is justified in the first place. In this section, we identify the different rationales for government funding of R& D and explore what rationales can be used to support the existence of the NNI. Public funding of research and development can be motivated by three different goals. First, government funding can be intended to support basic...

Doped TiO2

The visible-light photocatalytic activity of a doped TiO2 system was first pointed out in nitrogen-doped samples 13,43 . Sulfur-doped TiO2 in either anion-doping or cation-doping form was found to be active under visible light 18,19 . However, S-doped TiO2 suffers from catalytic poisoning by the sulfate ions generated 44 . Carbon-doped TiO2 was then fabricated using several methods 45 , and visible-light photocatalytic activity was reported for these C-doped samples 15,16 . However, the...

How Can You See Feel or Hear Something so Incredibly Tiny

In 1981, the scanning tunneling microscope (STM) was invented, followed 4 years later by the atomic force microscope (AFM) and that's when nanoscience and nanotechnology really started to take off. Various forms of scanning probe microscopes (SPM) based on these discoveries are essential for many areas of today's research. Conventional optics cannot resolve objects measuring tens of nanometers or less because the visible wavelength of light is roughly between 400 and 750 nm. With scanning probe...

Physical Properties Of Micelles

Again, the common aspects of the self-assembly of surfactant (and amphiphilic polymer) systems are that it is a thermodynamic, random, and nonhierarchical process with molecular-length scale. This section provides details on this issue. The definitions of three important parameters for micelles also will be given critical micelle concentration (cmc), aggregation number (n), and degree of counterion binding on the surface of micelles (a) (Tanford, 1980 Zana, 1991 Nagarajan and Ruckenstein, 2000...

Hybrids Incorporating Optically Active Centres 12321 Organic Dyes

Sol-gel derived dyes containing transparent matrices are an alternative to traditional liquid phase dye lasers since these gels are prepared under mild temperature conditions and they can be easily enriched with laser dyes without damaging them. Moreover, as the solubility of most dyes is limited in pure silica matrices, intensive efforts have been made in the last decade to synthesize dyes containing organic-inorganic hybrids 65, 66, 111-114 . Figure 12.19 depicts a few representative...

Static Mixertubular Reactor Setup

As mentioned in the Introduction, a first step to overcoming the drawbacks of stirred tank reactors is the use of a continuous operating tubular reactor equipped with a static mixer 30 . The static mixer contains bow-tie shaped helical static mixing elements with clockwise and counterclockwise orientations with an internal width of 14.3 mm. BaTiO3 powder with a mean particle size of 80 nm and a specific surface area of 25 m2 g was synthesized using this static mixer-tubular reactor setup 31 ....

Charles Berman

Charles Berman is a principal shareholder with the law firm Greenberg Traurig, LLP, in Santa Monica, California, and he is Co-Chair of the national patent prosecution practice of the firm. He has been active in all areas of intellectual property law for more than 35 years. He has been practicing in Los Angeles since 1978, and practiced in South Africa prior to that time. He has also worked with European patent attorneys. Berman has extensive IP experience in the United States and foreign...

Interferometric Grating Sensor

In the actual probe geometry (shown in Fig. 1.2), the large and small masses correspond to cantilever beam and the tip-coupled force sensor at the end, respectively. In order to measure the differential tip-cantilever displacement, an interferometric grating displacement sensor 38-40 is used. The grating sensor is designed such that the tip is mechanically coupled to alternating grating fingers, while the rest of the grating fingers are isolated from each other and remain free. Therefore, when...

Effects of Alloy Compositions on the Ferromagnetic Glass Properties

The magnetomechanical properties of ferromagnetic glasses, such as magnetostrictive and magnetoelastic coupling, magnetic hardness, hysteresis losses, and anisotropy are all dependent upon alloy composition. Although there are no general theories for predicting the effects of alloy composition on the properties of the ferromagnetic glasses, several models have been developed to describe the effects of alloy composition on Fe-rich and Co-rich ferromagnetic glasses 70 . In general, Fe-rich...

Specific Examples of High Throughput Methodology Applied to Photoelectrocatalysts

To date, there has been no cost-effective solar photoelectrocatalyst material system identified for the production of any product, including hydrogen however, efforts in several groups are ongoing using high-throughput synthesis and screening in attempts to identify new candidate materials. The primary unmet challenge continues to be the identification of a cost-effective solar-photon absorber suitable for photoelectrocatalysis. Once the absorber material has been identified, optimization of...

Graphite and Its Structure

The structure of graphite had been elucidated from 1917 on by Debye, Scherrer, Grimm, Otto, and Bernal. It is characterized by a succession of distinct so-called graphene layers that spread over an xy-plane. They are stacked in a z-direction, and there are only weak van der Waals interactions among them (Figure 1.7). Within one graphene layer, the carbon atoms are situated at the corners of regular hexagons that constitute a two -dimensional lattice. From each C -atom there are three o-bonds...

Results And Disscussions

Figure. 1 shows XRD patterns of the products prepared by CRN and GRN methods using the same zeolite at 1400 C for 120 min. P-SiAlON was a main phase in both samples, but XRD pattern of the P-SiAlONs phase obtained by CRN method indicated the broad and splited peak in higher diffraction angle. This fact indicates the formation of (3-SiAlONs with different compositions. On the other hand, high-purity P-SiAlON with an uniform composition was confirmed in the sample produced by GRN (Fig. 1(b)). XRD...

Memetics A Potential New Science

Strong and William Sims Bainbridge, National Science Foundation 2 In the information society of the twenty-first century, the most valuable resource will not be iron or oil but culture. However, the sciences of human culture have lacked a formal paradigm and a rigorous methodology. A fresh approach to culture, based on biological metaphors and information science methodologies, could vastly enhance the human and economic value of our cultural heritage and provide cognitive science with...

Disadvantages of QDs

The main disadvantages of QDs are due to their composition of heavy metals (e.g., Cd, Pb, and Se which are known to be toxic to vertebrate systems at parts-per-million concentrations (Hardman 2006)) and the instability of uncoated QDs when exposed to UV radiation which leads to the release of heavy metal ions. For example, the free cadmium in solution can bind to sulfhydryl groups of critical mitochondrial proteins. Thiol group inactivation then leads to oxidative stress and mitochondrial...

Electrodeposition of Metal Oxides and Other Compounds

Among the first studies on the electrodeposition of compounds in the 1980s was the development of methods to prepare thin films of II IV compound semiconductors 18,19 . For example, electrodeposition of cadmium sulfide from solutions of cadmium salts was carried out by electroreduction of elemental sulfur either dissolved in dimethylsulfoxide or released by decomposition of thiosulfate in water. Light absorbers in thin-film photovoltaic cells such as CdTe and Cu(In, Ga)Se2 were also prepared by...

MEMS for Wireless Base Stations Satellites and Nanosatellites

MEMS devices and components incorporating NT have revolutionized the wireless, commercial communications, and satellite communications sectors. MEMS-based RF switches, phase shifters, power amplifiers, and printed circuit antennas are best suited for wireless and space communications systems because NT conserves energy and minimum power consumption. Therefore, as a technology that conserves energy and minimizes electrical power consumption, RF-MEMS switches and phase shifters are critical to...

Near Field Scanning Optical Microscopy

A TopoMetrix Aurora-2 NSOM was used for our experiments. A schematic of the NSOM system is shown in Figure 12.3. The fiber-optic probe (aperture size 60-100 nm) attached to a piezoelectric tuning fork was mounted on the removable Aurora-2 microscope head and positioned above the sample. A resonating frequency ranging between 90 and 100 kHz was selected with less than 1 nm lateral amplitude at the probe end. Samples were mounted directly beneath the tip on a X-Y piezo scanner that is used to...

Rfmems Technology for Base Station Requirements

An infrastructure vendor is fully equipped to provide a variety of base station configurations (Figure 1.5) to meet network operator needs. In addition to various air interface standards, such as global system for mobile (GSM) communications, universal mobile telecommunications system (UMTS), and code division multiple access (CDMA), there are also different frequency bands of operations and various RF power levels as illustrated in Figure 1.6. It is important to mention that weight, size, and...

Clamped Clamped Beam Micro Resonator

Important components of this micro-resonator such as the electrode, resonator beam, coupling beam, and the anchors are shown in Figure 8.5b. Critical device parameters include the resonator beam dimensions (length, width, and thickness), electrode width, initial gap, Young's modulus (E), resonator stiffness and mass, bias voltage, and catastrophic voltage. This particular CCB device uses PP capacitive transducers with small gap spacing, which make these resonators to retain high mechanical...

Symmetric Biomimetic Selfassembled Aggregates

The bio-mimetic self-assemblies described so far were the asymmetric directional packing processes of their primary building units. However, there are some exceptional cases where the self-assembly occurs still through a directional but symmetric packing mode (or with a least degree of asymmetric packing). Even though the cooperative interaction with the structural constraint of the molecular building units is critical to guide the direction of the self- assembly, the major attractive forces...

One Word Plastics

When Rich went off to college in 1995, his dad said, One word World Wide Web. But that's three words, Rich said. His dad was, in his own way, trying to express the future importance of the Internet by mirroring the famous line from the 1967 movie The Graduate, Just one word plastics. At 18, Rich (like most teenagers at that age) thought he knew everything and didn't listen to the advice the way he probably should have. When he graduated from college, his dad approached him again and said, One...

Sample Preparation Of Nanomaterials For Ebsd

The main sample preparation requirement for EBSD studies is that the sample surface shall be clean, representative of the bulk of the material and free from damage or deformation resulting from the preparation process. Some materials, like epitaxial or heteroepitaxial layers may require no additional sample preparation steps and EBSD patterns may be obtained from the sample in the as-deposited condition. Other samples may require more complex procedures to produce good samples for EBSD. For...

When Atoms From The Lattice The Discrete Energy Levels Of The Atom Asre Smduged

One obvious property that will be different is the electronic structure. Table 4.1 gives the result of density functional calculations of some of the electronic properties of A1i3. Notice that binding energy per atom in A1i3 is less than in the bulk aluminum. The Al13 cluster has an unpaired electron in the outer shell. The addition of an electron to form Al 3(-) closes the shell with a significant increase in the binding energy. The molecular orbital approach is also...

Application of Diamondoids as MBBs

The importance of applications of diamondoids in nanotechnology is their potential role as MBBs. Diamondoids have noticeable electronic properties. In fact, they are H-terminated diamond and the only semiconductors that show a negative electron affinity 12 . Diamondoids may be used in self-assembly, positional assembly, nanofabrica-tion, and many other important methods in nanotechnology. Although adamantane has been the subject of many research projects in the field of pharmacophore-based drug...

Nanotechnology is Key to Improving Fuel Cell Performance

Modern fuel cells have the potential to revolutionize transportation. Like battery electric vehicles, fuel cell vehicles are propelled by electric motors. But whereas battery electric vehicles use electricity from an external source and store it in a battery, fuel cells on board a vehicle are electrochemical devices that convert a fuel's chemical energy directly to electrical energy with high efficiency and without combustion. One of the leading fuel cell technologies developed, in particular...

Quantum Nature of the Nanoworld

The particles of matter (electrons, protons, neutrons) provide limits to the smallness of anything composed of chemical matter, which is itself composed of atoms. The rules that these particles obey are different from the rules of macroscopic matter. An understanding of the rules is useful to understand the structure of atoms and chemical matter. An understanding of these rules, and of the relation between the wave and particle natures of light, is also key to understanding deviations from...

Overconsumption or moderation

From an ethical point of view the continuation of consumerist over-consumption may be regarded as a human failure to resist taking advantage of, and submitting to, craving and greed. Here the virtues of self-understanding, self-discipline and altruism may come to mind, among others. Every world religion and moral outlook has a central place for acknowledging and subduing greed and promoting a sharing attitude. Yet there is perhaps an increasing perception that greed is no longer just an...

Elastic and Anelastic Properties of Nanocrystalline Materials

There are very few theoretical considerations related to the elasticity of nanocrystalline materials. Some early experimental results have prompted ideas on elastic properties being dependent on the volume fraction of lower-density grain boundary phase in relation to the bulk phase 39 . Later, however, the experimental results 40, 41 have, according to Morris 2 , quite convincingly showed that the grain size refinement does not play any obvious role in modifying Young's modulus, shear modulus,...

Eleftrojtprohe Aperture mrad

C. 1 raft p 5x10s Acm -fr J Ce 1 raia K JOkiV AE 0.5 tV Figure 8. Plots (a) show the dependence of the probe size on the probe-aperture angle for diffraction-limited probe, spherical aberration limited probe, chromatic aberration limited probe, and the root mean square sum of these contributions for 1-keV and 30-keV electrons, respectively. Plots (b) show the dependence of minimum probe size on the primary electron energy based on the root mean square (RMS) rule and the root power sum (RPS)...

Spinbath collector yarn

In this recently published method, developed by our group at Stellenbosch University,38 continuous uniaxial fiber bundle yarns are obtained by electrospinning onto the surface of a liquid reservoir counter-electrode. The web of electrospun fibers, which forms on the surface of the spin-bath, is drawn at low linear velocity (ca. 0.05 m s) over the liquid surface and onto a take-up roller. A diagrammatic representation of the electrospinning set-up is given in Fig. 3.9. All the yarns obtained...

Formation of Fullerene Complexes

Braun and co-workers studied the mechanochemical synthesis of the supramolecular host-guest complex of C60 and gamma-cyclodextrin (y-CD) 83 . The equipment used in the mechanochemical investigation was a 50 ml agate ball mill (diameter 70 mm, height 15 mm) (Pulverisette, Type 701, Fritsch, Germany). A homogenized mixture of 10 mg of C60 and 100 mg of y-CD was ball-milled for about 20 h at room temperature. A 1 2 C60-y-CD complex 41 with a bicapped structure was supposed to be formed (Fig. 19)....

Nano Tools Nano Devices Nano Systems

Due to the ability of graphene to expand slightly when electrically charged, nanotubes have been found to act conveniently as actuators. Kim et al. 3.346 demonstrated it by designing nano-tweezers able to grab, manipulate, release nano-objects (the nano-bead having been handled for the demonstration was actually Fig. 3.31 Sketch explaining how the first nano-tweezers were designed. First is a glass micropipette (dark cone, top). Then two Au coatings (in grey, middle) are deposited so that they...

Replacing joints with better stuff

Thus far, nanotechnology offers almost magical transformations of materials, strengthening our current versions of standard steel, glass, and plastic into something revolutionary. (Don't believe us Check out Chapter 5.) When applied to biological materials, nanotech will accomplish similar dramatic changes. To do so, however, it will have to compensate for biomaterials' dynamic (ever-changing) construction. Not sure what's so dynamic about biomaterials Read on to find out. Bones are actually a...

General Principles of Micromagnetics

Classical (zero-temperature) micromagnetics describe magnetic materials in a nanometric lengthscale where each discretization unit is represented by a large magnetic moment that could be described in a semiclassical approximation, i.e., no quantum effects are taken into account. The principle of micromagnetics is due to Brown 107 who derived the micromagnetic equations for the equilibrium properties. The method consists in discretizing the magnetic film in finite differences 108-110 or finite...

History Of Neurosurgery

The art of neurosurgery dates back to the Neolithic time (late stone age) with evidence of brain surgery found in the unearthed remains from this era 4,15,21,27, 32 . Many ancient FIGURE 6.1. Schematic illustration of the central nervous system. Neurosurgery refers to the operative and subsequent non-operative care of disorders that affect the central, peripheral and autonomic nervous system as well as the management of pain. Neurosurgeons also treat disorders of the vascular and skeletal...

Spin Injection the Johnson Silsbee Effect

Johnson and Silsbee 13 demonstrated experimentally that a non-equilibrium density of spin-polarized electrons can be transferred from a ferromagnet into a nonmagnetic metal, like aluminum, under proper conditions. An important corollary, demonstrated experimentally in their pioneering work, is that the same type of fer-romagnet-insulator-normal metal junction responds to the presence of non-equilib- Figure 8.10 Geometry of the spin injection device 14 . (a) SEM image of device with spacing L of...

General Applications of Diamondoids

Each successively higher diamondoid family shows increasing structural complexity and varieties of molecular geometries. Sui generis properties of diamondoids have provoked an extensive range of inquiries in different fields of science and technology. For example, they have been used as templates for crystallization of zeolite catalysts 25 , the synthesis of high-temperature polymers 26 , and in pharmacology. In pharmacology, two adamantane derivatives, Amantadine (1-adaman-taneamine...

Gas Phase Etching

Major limitations of wet chemical etching of silicon (dioxide) with hydrofluoric acid (HF) include the necessity for a subsequent rinse and dry step after each etch step, which is critical when dealing with fragile structures. Moreover, the hydrophobic silicon surface strongly attracts particles and other bath contaminations. Another drawback is the inability of wet chemicals to penetrate small geometries with high aspect ratios due to surface tension. Moreover, as wafer size continues to...

STM Probe Construction

The STM probe should have a cantilever integrated with a sharp metal tip with a low aspect ratio (tip length tip shank) to minimize flexural vibrations. Ideally, the tip should be atomically sharp, but in practice most tip preparation methods produce a tip with a rather ragged profile that consists of several asperities with the one closest to the surface responsible for tunneling. STM cantilevers with sharp tips are typically fabricated from metal wires of tungsten (W), platinum-iridium...

Limitations of Macroscopic WO3

The above example illustrates the intrinsic limitations in efficiency associated with the use of indirect optical transition semiconductors, such as WO3, as sunlight-driven photoelectrodes. Given the low absorption coefficients, a, in WO3 for photons with energies close to the bandgap, the optical penetration depth, 1 a, for light of visible wavelengths may be of the order of several micrometers 6,13 . In addition to this, the hole diffusion length, Lp, in materials with an indirect optical...

Passive Micropumps

A passive system is defined inherently as one that does not require an external energy source. Thus, the term passive micropump might seem misnomer upon initial inspection. However, there have been some efforts dedicated to realizing a passive micropump that essentially does not draw energy from an external source, but stores the required actuation energy in some form and converts it to mechanical energy on demand. Passive Micropump Based on Osmotic Pressure Nagakura et al. 9.71 have...

Controlling the GMI Effect

Equations (51) and (52) show that the impedance of the ferromagnetic glasses increases with the factor M t, e for both ferromagnetic glass wires and ribbons. Hence one can increase the sensitivity of a GMI sensor by increasing the operating frequency. In addition, it is also found that the transverse and circumferential permeabilities are dependent upon the amplitude of the driving current, applied stress, and annealing temperature. The effect of ac frequency on the GMI was studied by Knobel et...

From Nanoscale To Macroscale

Cement based materials, such as hydrated cement pastes, mortars, plain and fibre reinforced concretes are widely used in the construction of modem structures. During their service life, depending on the environmental conditions they are in, many structures are exposed to various types of aggressive agents. Intrusion of the aggressive agents into the cement based materials, which directly affects durability, is generally controlled by the diffusivity and permeability of the material. In...

Electromagnetic Transport in Heterostructures

Theoreticians pointed out that the theoretical framework used in many instances to explain the electromagnetic transport in granular materials is a modelization in terms of a continuum media. As previously observed elsewhere 44 , the basic assumption used is that there exist length scales above which fluctuations at the microscopic level may be ignored. In this way, useful predictions of a granular material's bulk properties can be made with no references to its discrete nature. At issue is the...

Evanescent Wave Spectroscopy Of Atomic Vapors

This section deals with applications of evanescent waves to the detailed spectroscopy of atomic vapors near dielectric surfaces. Boissel and Kerherve reported in 1981 the absorption of the sodium D2 line when the sodium vapor was excited by an EW at a sapphire prism surface 14 . This can be thought of as the first experiment on linear EWS of atomic vapors. The authors calculated based on the theory of optical response of atoms in the vicinity of a bounding surface the absorption of the EW in...

Optical Printing

Optical lithography comprises the formation of images with visible or near-UV radiation (A 300-380 nm) in a resist (e.g., Novolac) using shadow or projection printing. Shadow printing may be employed where the gap between mask and wafer is small. In case of projection printing, some sort of image-forming system (e.g., a 4 1 demagnification lens) is interposed between mask and wafer. The linewidth limit of optical printing lies near 0.4 m, although 0.2 m features may eventually be printed under...

Characteristics of Pesticides and Their Environmental Effects

The recalcitrance of a pesticide is largely determined by its chemical structure. Some herbicides (such as 2,4-D) are susceptible to environmental degradation, while others (including most chlorinated insecticides such as endosulfan, hep-tachlor, and dieldrin) are considerably more resistant. Solubility will affect not only transport but also pesticide degradation since degradation is believed to occur mainly in the solution phase. The characteristics and structures of pesticides investigated...

Fullerene metal complexes

In the exohedral fullerene-transition metal complexes, the fullerenes act as an olefinic ligand and bind the metal center in -2-fashion 109 . There are several examples of -5-fullerene metal complexes 110 . For this purpose a cyclopentadiene moiety is generated on the fullerene surface from a pentaadduct, such as C60Ph5H. A number of cyclopentadienyl (Cp) metal complexes (-5-C60Ph5)MLn (43) (MLn Li, K, Tl, Cu PEt3) are synthesized (Fig. 17) using the cyclopentadienyl ring generated through...

Fullerene Photochemistry and ROS Generation Potential

Similar to the cases of the metal oxide and sulfide semiconductors, the photochemical properties of fullerenes can be viewed in the context of excitation of electrons across a bandgap. For example, the bandgap of pure C60 has been reported to be 2.3 eV, which is comparable to that of iron oxide polymorphs (Table 5.3). The bandgap for carbon nanotubes (CNTs) depends on its chirality and is inversely proportional to the diameter of the nanotube. In the case of ROS generation by fullerenes, they...

Biological Examples of Nanomotors and Nanodevices

Biology provides examples of nanometer scale motors and electrical devices, which can be seen as limits of smallness. If nature can make these (only recently perceived) nanoscale machines, why, some ask, cannot human technology meet and eventually exceed these results It is certainly a challenge. The contraction of muscle occurs through the concerted action of large numbers of muscle myosin molecules, which walk along actin filaments in animal tissue. Other sorts of motors rotate flagella,...

The Meltblowing Process

The concept of meltblowing was first demonstrated in 1954 by Van A. Wente, of the Naval Research Laboratories, who was interested in developing fine fibers to collect radioactive particles in the upper atmosphere to monitor worldwide testing of nuclear weapons. In this process, an extruder forced a molten polymer through a row of fine orifices directly into two converging high-velocity streams of heated air or other gas. It was claimed that fibers as small as 0.1 to 1 im can be formed by this...

Nanoindentation for Moisture Damage Study

In a nanoindentation test, the movement of a diamond probe in contact with a sample surface is measured by applying an increasing load. Time, load, and displacement are recorded during the test. The elastic and plastic properties of the sample are determined from the load-displacement data. Stiffness and hardness are the most common mechanical properties measured from indentation data. Stiffness is the ratio of stress to strain. Hardness is the resistance to permanent deformation. It is defined...

Ultrahigh molecular weight polyethyleneclay nanocomposites

Ultra-high molecular weight polyethylene (UHMWPE) has extremely high abrasion resistance when compared with other thermoplastics. It also has exceptional impact resistance, even at cryogenic temperatures, and is superior to stainless steel. Other advantages of UHMWPE include low moisture absorption, good electrical and thermal insulation, self-lubrication and chemical inertness (except in some acids). Some formulations in which UHMWPE can be used are sheet, rod and tube. Some of its excellent...

Colossal Magnetoresistive Manganites

Recently, it has been recognized that some perovskite oxides (divalent doped lanthanum and rare-earth mangan-ites and some related oxides of Ruddlesden-Popper series 8 ) possess large negative magnetoresistance or colossal magnetoresistance (CMR). These materials undergo phase transition from the paramagnetic (PM) insulating (semiconducting) phase to the ferromagnetic (FM) metallic phase below the corresponding Curie temperature. In these per-ovskite oxides, metal-insulator transition (MIT)...

BaTiO3

Barium titanate has a cubic perovskite structure in its high-symmetry, paraelectric phase (above TC 125 C). With a decrease in the temperature, it transforms successively to three structurally distinct ferroelectric phases a tetragonal phase (TC < T < 5 C), an orthorhombic phase (5 C < T < -90 C), and a rhombohedral phase (T < -90 C). All three transitions are of the first order. Early measurements involved sintered samples with grain size in the submicrometer to few micrometer range...

Nanosensor Fabrication 41 Fabrication of Nanofiber Probes

This section discusses the protocols and instrumental systems involved in the fabrication of fiber-optic nanoprobes. Two methods are generally used for preparing the nanofiber tips. The so-called heat-and-pull method is the most commonly used. This method consists of local heating of a glass fiber using a laser or a filament, and subsequently pulling the fiber apart. The shape of the nanofiber tips obtained depends on controllable experimental parameters such as the temperature and the timing...

Design Aspects Operating Principle and Description of Critical Elements

A 3-bit distributed MEMS phase shifter consists of three 1-bit phase shifters designated for 180 , 90 , and 45 phase shift, respectively. It is important to mention that each one-bit phase shifter comprises of a CPW transmission-line loaded periodically using several shunt MEMS capacitors. The estimated length of the phase shifter circuit is 11 mm and the device can be fabricated on a glass substrate with dielectric constant of 5.7 to keep the fabrication cost to minimum. The phase shift of the...

Pn Assemblies

Semiconductors with bandgaps lower than 2.2 eV lack sufficient photovoltage and need an external bias potential to split water. Iron oxide (a-Fe2O3) has a bandgap of 2.2 eV, which makes it an ideal semiconductor photoelectrode, due to its capability to absorb most of the photons of the solar spectrum. However, use of iron oxide alone cannot split water, mainly due to its inappropriate energy levels with respect to the redox levels of water. The use of a narrow bandgap n-type anode in...

Biomolecular Templated NW Assembly

The steady trend in the electronics industry toward components having ever-smaller dimensions has stimulated the development of alternative bottom-up fabrication technologies to compete with conventional micro- and nano- lithography, which are expected to become extremely expensive as the feature sizes of future electronic circuits approach the limits of optical lithography (112). Bottom-up approaches, which rely on self-assembly (or self-organization) that often utilizes biological molecules,...

Polyfullerenes And Fulleropolymers

In view of the interesting properties of fullerenes, there have been a number of studies exploring the behavior of fullerenes under the routine polymerization conditions. Extensive literature is available on the subject, with a number of review articles 397 . Polyfullerene ideally should be a linear chain of the fullerene molecules joined by one or more covalent bonds. Fullerenes are known to undergo photopolymerization in the solid state 398 . In this reaction a 2 + 2 cycloaddition between two...

By Dehydration and Rehydration

The dehydration of a vesicle suspension followed by a controlled rehydration at a temperature above Tm leads to the fusion of small vesicles present in the suspension, resulting finally in the formation mainly of MLVs 147-149 . This procedure is based on the instability of dried SUVs and a lipid lamellae formation (SUV fusion) during the water removal. The resulting vesicle suspensions are referred to as dehydration-rehydration vesicles or dried-reconstituted vesicles (DRVs) 31 . DRVs are often...

OVD Foil Microstructures

The first application of OVD technology as an anti-counterfeiting feature was the result of the adaptation of existing holographic technology to high volume manufacture by direct embossing onto foil and the application of that foil onto the security document by a hot stamping process. The security hologram was developed initially by the American Bank Note Company through its subsidiary, American Bank Note Holographics (ABNH) and was first adopted by MASTERCARD in 1982 in the form of a 2D 3D...

Extreme Ultraviolet Printing

To extend the ongoing technological trends to wavelengths below 100 nm, processes of a short-wavelength imaging method are explored, which includes reduction optics analogs to optical projection printing. Such a reduction scheme with the ability of making diffraction-limited images would take full advantage of the short wavelength. The method, initially called soft X-ray projection lithography but later named extreme-ultraviolet printing (EUVP with wavelength between 4 and 200 nm), uses...

Diamond Synthesis Routes

Diamond is everywhere inside supernovae, with star dusts, in meteorites, around impact craters, and under ground, consequently, there are numerous ways that can form diamond. However, all these synthesis routes employ a common strategy, namely, by squeezing loosely held carbon atoms surrounded by contact neighbors of 0 (sp0, e.g. C), 1 (spa5, e.g. C2), 2 (sp1, e.g. car-byne, C C ), 3 (sp2, e.g. graphite), and 4 (sp3, e.g. methane) to make them more compact by forming a continuous network of...

Self Assembly of Aligned ZnO Nanorods on Any Substrates via a Mineral Interface

As an alternative to using ZnO as a buffer layer to promote growth in hydrothermal synthesis, we research a method that can promote ZnO nanorod growth on any substrate, regardless of its crystal type and shape (flat or curved). One way to reduce the interfacial energy between the nucleus and substrate is through surface modification. Taking a cue from biomineralization, where organisms control surface nucleation and growth on substrate materials that are relatively inert, we have identified a...

MDL Stress and Torque Sensors

Hristoforou and Reilly 17 designed a simple MDL force sensor using a Metglas 2605SC ribbon. The sensor is similar to that shown in Figure 29, but with the excitation coil Figure 29. The basic arrangement of a magnetoelastic delay line. An elastic wave is generated by the excitation coil and propagated along the MDL due to the magnetostrictive effect. As the elastic wave propagates to the other end of the MDL, it causes an induction voltage at the sensing coil by the inverse magnetostrictive...

A Matlab Codes

The MATLAB codes for the toy models can also be obtained at www.nanohub.purdue.edu. Toy model, one level Inputs (all in eV) E0 - 5 . 5 E f -5 gam1 0 .2 gam2 0.2 U 1 Constants (all MKS, except energy which is in eV) hbar 1.06e-34 q 1.6e-19 IE (2*q*q) hbar kT .025 Bias (calculate 101 voltage points in -4 4 range) nV 101 VV linspace(-4,4,nV) dV VV(2)-VV(1) N0 2 (1 + exp((E0-Ef) kT) ) for iV 1 nV Voltage loop UU 0 dU 1 V VV(iV) mu1 Ef-(V 2) mu2 Ef+(V 2) while dU> 1e-6 SCF E E0+UU f1 1...