Proximity Xray Lithography

Proximity X-ray lithography is essentially a form of shadow printing'' a mask is held in close proximity to the substrate surface, and the image is simply produced on exposure by the shadow of the mask on the surface. Proximity techniques were used in the early days of optical lithography, but have long since been super-ceded by projection techniques the former are more susceptible to resolution-limiting diffraction effects. Resolution is less of an issue with proximity printing using X-rays,...

References

The Academic Press Dictionary of Science and Technology, Academic Press San Diego, 1991. 2. Aviram, A. Ratner, M.A. Molecular rectifiers. Chem. Phys. Lett. 1974, 29, 277-283. 3. Kahn, O. Martinez, C.J. Spin transition polymers from molecular materials toward memory devices. Science 1998, 279 (5347), 44-48. 4. Behm, R.J. Garcia, N. Rohrer, H. Scanning Tunneling Microscopy and Related Methods Kluwer Academic Publishers Dordrecht, 1990. 5. Aviram, A. Joachim, C. Pomerantz, M. Evidence of switching...

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Fig. 9 (A-B) HRTEM image (A) and SAED patterns (B) for a-Fe(C) and g-Fe(C) nanoparticles. Note that arrows indicate the carbon layers. Source From Ref. 11 . Fig. 10 (A-B) HRTEM image (A) and SAED patterns (B) for Fe3C phases in Fe(C) nanoparticles. Note that arrows indicate the carbon layers and structure defects. Source From Ref. 11 . Fig. 10 (A-B) HRTEM image (A) and SAED patterns (B) for Fe3C phases in Fe(C) nanoparticles. Note that arrows indicate the carbon layers and structure defects....

Uniaxial and Biaxial Compression of Diamond Coated Silicon

Buckling delamination of a coating is unwanted in industrial applications. Thus, a fundamental understanding of the stress relief patterns or buckling modes and the stress levels at which buckling occurs is necessary. Some very interesting buckling patterns such as telephone-cord, sinusoidal wave, sinusoidal shape with extra branches, and a strings-of-beads pattern have been reported in Refs. 15,17,18 . Gioia and Ortiz 10 have compiled most of these patterns in their paper on delamination of...

Introduction

Studies on system of magnetic nanoparticles with sizes in the nanometer scale have been the object of intensive research because of their many technological applications and unique magnetic properties that differ considerably from those of bulk materials 1-31 Nanometer magnetic particles exhibit specific properties such as superparamagnetism 4 because of their very small sizes and fundamental change in the coordination, symmetry, and confinement 1-3 Superpara-magnetism is regarded as a unique...

Nanodiamond Sources Nanodiamonds in the

Nanoscale diamonds were discovered in 1987 by Lewis et al. 5 in meteorites. Not all meteorites contain diamonds. At this time, nanodiamonds have been found in specific types of meteorites, the so-called ''carbonaceous chondrites.'' Two major sources of nanodiamonds are the ''Allende'' chondrite (C3V type), which weighed several tons when it fell on Mexico in 1969, and also other types of chondrites, such as the Murchison meteorite (type C2). The nanodiamonds found in these meteorites have a...

Quantum Dot Based Neuromorphic Architectures

In 1995, Roychowdhury and coworkers proposed a revolutionary new idea for utilizing quantum dots for signal processing and computation. 17,18 Their scheme was not based on logic circuits, so that they did not need the properties necessary to build logic circuits. Instead, they proposed to build a neural network architecture. They also realized that making connections to quantum dots will be a nearly insurmountable challenge because quantum dots are so small that aligning multiple (or for that...

Conclusion

In summary, two types of nickel (Ni) and iron (Fe) nanoparticles, carbon-coated Ni and Fe nanoparticles Ni(C) and Fe(C) , as well as pure fcc Ni and a-Fe nanoparticles that coated with oxide layers Ni(O) and Fe(O) have been successfully synthesized using modified graphite arc-discharge method. Highresolution transmission electron microscopy (HRTEM), electron diffraction (SAED), and X-ray diffraction (XRD) analyses have been used to characterize these distinct structural morphologies of Ni and...

Info

Synthesis and testing 26. of components. Acc. Chem. Res. 2000, 33 (11), 791-804. 6. Heath, J.R. Wires, switches, and wiring. A route toward a chemically assembled electronic nanocomputer. Pure Appl. Chem. 2000, 72 (1-2), 11-20. 27. 7. Reed, M.A. Tour, J.M. Computing with molecules. Sci. Am. June 2000, 2000, 68-75. 8. Overton, R. Molecular electronics will change everything. Wired 2000, 8 (7), 242-251. 9. Heath, J.R. Kuekes, P.J. Snider, G.S. Williams, R.S. A...

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Scheme 5 Gold nanoparticle aggregate driven by molecular recognition between surface-immobilized PSH-b-CD and ferrocene dimmer. By using similar host-guest chemistry, another type of interesting organic inorganic nanocomposites was constructed in the aqueous solution. 29 Direct mixing of PSH-g-CD-Au (3 nm) and solid C60 in water led to large nanoparticle aggregates with average size of around 290 nm as characterized by PCS analysis and TEM measurement. In an alternative approach, mixing a...

Molecular Finite Automata

Two programmable, autonomous finite automata made of biomolecules were demonstrated by Benenson et al. 26,27 Both use a DNA molecule as input, DNA molecules as software, encoding the automaton transitions, and DNA-manipulating enzymes as hardware. The differences between the two are the source of energy for the computation and the reuse of software molecules. The first automaton relies on ATP as an energy source and consumes its software molecules during computation, while the second utilizes...

Dynamic Shock Consolidation Of Powders

Dynamic consolidation of powders using high-pressure shock waves is a potentially important method for the fabrication of bulk nanocrystalline or metastable materials.113-171 The one-stage densification bonding process occurring in the microsecond duration of the shock pulse involves the intense heterogeneous deposition of energy into particles, resulting in annihilation of the voids via plastic flow, and interparticle bonding. With this approach, it is possible to fabricate nano-composite bulk...

The Native Oxide and Its Growth Kinetics

An ideally hydrogen-terminated surface is presumed to be indefinitely stable (in the laboratory timescale) in air. Although the (100) surface resulting after aqueous HF etching of the overlying oxide is expected to be terminated with silicon dihydride, the hydrogen terminations actually form, however, a heterogeneous family of monohydride, dihydride, and trihydride spe-cies, 35,36 and the surface still contains an appreciable amount of silicon-oxygen centers, roughly corresponding to 0.2-0.5...

Selfassembly Methods To Grow Nanocolloidal Gold Films

Many different ways have been employed to assemble colloidal particles into disordered structures or highly ordered superlattices. Most of these methods have also been applied to nanometer-sized gold particles, but because their size is orders of magnitude smaller than, for example, the particles used in photonic band gap applications, the results are often different. One of the most frequently used methods, and without doubt the most often described 1-20 assembly technique, involves the...

Nanodiamond Properties

Very few theoretical studies of single nanodiamonds properties have been performed. Halicioglu 36 relaxed spherical nanometric diamond slabs with Brenner potentials. The so-formed structures exhibit inward relaxation from the top surface layers, the interatomic distance between neighboring atoms decreasing from the center of the cluster to the surface. They also noticed significant variations in relative cohesive energy with respect to bulk diamond. Recently, an ab initio molecular dynamics...

Stern Grahame model

The Gouy-Chapman model of EDL includes some unrealistic cases. For example, the ions are assumed as point charges and any specific effects related to the ion size are neglected. Therefore the adsorption densities on the solid surface calculated for moderate surface potentials and ionic strength values are so high that they are physically impossible. Also, the solvent is assumed to have continuous properties everywhere in solution however, its properties such as the dielectric constant and the...

Helmholtz compact layer model

The earliest model of the EDL, in which a rigid layer away from the surface in solution consists of oppositely charged ions, was proposed in 1879 by Helmholtz. 16 Also, the surface charge of particle is equal to that of rigid layer. Because this model ignores the disrupting effect of thermal agitation, it is unreasonable. This model is known as a molecular condenser model owing to its similarity to a parallel plate condenser. 1 Using the law of distribution of EDL, the potential C (V) across...

Equilibrium Phase Diagram

Once we have an expression for the Helmholtz energy, the chemical potential m and the osmotic pressure P can be derived following standard thermodynamic relations where V'' stands for the total volume. A fluid-fluid coexistence curve is obtained from the criteria of phase equilibrium

Lattice Thermal Conductivity

The thermal vibrations of solids can be described by a superposition of plane progressive displacement waves, which transport heat energy. 1,2 The frequency of these waves extends over a wide spectrum. Each wave of frequency f has energy E and energy flow Ev, where v is its group velocity. In the limit of low frequencies, and wavelengths large compared to interatomic distances, these waves are identical to elastic waves in the corresponding continuum. For higher frequencies or shorter waves,...

Plzt

Piezolighter, piezofilter, surfacewave transducer, piezovibrator, flexible piezodetector Optical shutter, optical memory Na-S battery, O2 sensor Cathode luminescence, IR laser Optical communication fiber Optical shutter Magnetic tape Magnet seal PZT lead zirconate-titanate ceramics. PLZT lanthanum-modified lead zirconate-titanate ceramics. volumes. Lithium aluminosilicate ceramics have potential applications as solid electrolytes for utilization in solid high-energy density lithium battery...

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...

Motors In Nanotechnology

Technological revolutions often involve access to new materials, and the mastery of a new material is so fundamental to mankind that historic ages are defined by the state-of-the-art material, hence the stone age'' or bronze age.'' However, some technological revolutions are characterized by the newfound ability of man to convert energy into mechanical work, based, for example, on the invention of the steam engine, which powered the industrial revolution. Can nano-technology become a revolution...

Mechanical Applications

Industrial ceramics are widely employed in applications that require strong, hard, and abrasion-resistant materials. Metal-cutting tools, tipped with alumina, and tools made from silicon nitrides for cutting, shaping, grinding, and sanding iron, nickel-based alloys, and other metals are very commonly used. Other ceramics such as silicon nitrides and carbides are used to make components for high-temperature use such as valves and turbocharger rotors. Ceramic materials and metal-based ceramics...

Q

Stearic acid Bipolar pyridinium Anionic Pbl2 particle Fig. 2 Scheme for one monolayer of PbI2 nanoparticles in the stearic acid-bipolar pyridinium-PbI2 four layer structure. Source From Ref. 91 . photograph of the self-assembly film shows that all the PbI2 nanoparticles are round and closely packed, but without any large aggregates. As a comparison, one droplet of the PbI2 solution was dropped onto the grid and blown dry with N2. TEM measurements showed that the small particles had aggregated...

Prog. Mater. Sci. 1998 43 365-520

Nanocrystalline materials. Prog. Mater. Sci. 1989, 33, 223-315. 2. Yanakov, V. Wolf, D. Phillot, S.R. Mukerjee, A.K. Gleiter, H. Dislocation processes in the deformation of nanocrystalline aluminium by molecular-dynamics simulation. Nat. Mater. 2002, 1, 45-48. 3. Koch, C.C. The synthesis and structure of nanocrystalline materials produced by mechanical attrition a review. Nanostruct. Mater. 1993, 2, 109-129. 4. Greer, A.L. Crystallization of amorphous alloys. Metall. Mater....

Structural And Chemical Properties Of Micro And Mesoporous Materials

What Are The Chemical Properties Gold

Crystalline microporous materials are characterized by structurally well-defined voids, whose diameters exceed typical atomic dimensions. The fact that a molecule has to be able to access these pores puts a lower limit to the pore diameter of approximately 0.25 nm. If these voids are below 2 nm in diameter the material is called microporous, above mesoporous with an upper limit of approximately 50 nm . It should be noted that in mesoporous materials the pores are also periodically arranged...

Synthesis of Superfine Oxides in Liquid Metals

In this method, molten gallium, lead, or Pb-Bi alloy serve as the working medium. A metal M, whose chemical affinity for oxygen is larger than the oxygen affinity of the molten metal, is dissolved in the melt. Then the dissolved metal M is oxidized by bubbling water vapor or an oxidizing gas mixture H2O Ar through the melt. Superfine amorphous oxides of metals are formed as a result of selective oxidation. For example, oxidation of aluminum in molten gallium leads to formation of flocks of...

Physical and Structural Characteristics of Shock Consolidated Bulk Magnets

Figure 4 shows a plot illustrating the shock compaction conditions and resulting characteristics of the Pr2Fe14B a-Fe nanocomposite compacts. The shock Fig. 4 Plot of shock pressure and final density of compacts of Pr2Fe14B a-Fe nanocomposites shown as a function of compaction conditions initial packing density and gas-gun impact velocity or explosive-detonation velocity . The rectangular bars correspond to the shock pressure range for the corresponding gas-gun impact and explosive-loading...

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Methods For Ordered Nanoparticles

Fig. 11 TEM micrographs showing hexagonal arrays of thiolized Pd nanocrystals A Pd561 octanethiol, B Pd1415, octanethiol. Organized arrays of these nanocrystals extend to lengths over several microns. as elongated silver nanocrystals have been organized into ordered two-dimensional arrays. 95,125 Interestingly, ordered two-dimensional lattices containing thiolized spherical Au particles of two different sizes have been reported by Kiely et al. see Fig. 14 , 115 who found that the nanocrystals...

Chemical Vapor Deposition

Chemical vapor deposition CVD may be defined as the deposition of a solid on a heated surface from a chemical reaction in the vapor phase. It is a versatile process suitable for the manufacturing of coatings, powders, fibers, and monolithic components. It is possible to produce most metals, metal oxides, and non-metallic elements such as carbon and silicon as a large number of compounds including carbides, nitrides, oxides, intermetallics, and many others. The main advantage of CVD is that the...

Fouling and Nanofiltration Performance

Most municipal, industrial, and natural waters contain complex mixtures of dissolved, macromolecular colloidal, and particulate matter. Conventional processes used to pretreat NF feed waters fail to remove submicron colloids, macromolecules and dissolved matter. This matter accumulates at the membrane surface and results in severe performance decline a phenomenon known as fouling. Fouling of NF membranes may result in loss of both solvent flux and solute retention. A review of fouling studies...

Chemical Methods

The most potential and successful route for preparing homogeneous ceramic materials is liquid phase chemistry. The most widely used and perhaps most reliable method is the sol-gel method. There are many other wet chemistry methods known, such as microemulsion techniques and precipitation from solutions. Another novel technique is the mechanochemical synthesis method, which involves solid-state chemistry reactions. The synthesis of MMOs by sol-gel technique is one of several liquid phase methods...

Electrochemical Properties

Furthermore, the aforementioned characteristics are the primary factors that deprive the overall performance of the battery, which include the following Inferior electrochemical stability. Inferior mechanical properties. Poor thermal management capabilities. Inferior manufacturability. Potential hazards, especially of the liquid electrolytes, because of leakage, deposition, and explosion. To obviate the aforementioned deficiencies associated with cathode materials, researchers have developed a...

The Assemblies of FeC and FeO Particle Systems

Powder X-ray diffraction patterns of both Fe C and Fe O nanoparticles are shown in Fig. 8A and B, respectively. It is very apparent to reveal that a-Fe bcc , g-Fe fcc , and Fe3C orthorhombic nanophases are detected from the assemblies of Fe C nanoparticles these three phases are usually found in similarly prepared Fe-C nanocomposites. 19 However, dominant a-Fe nanophases and a small amount of Fe3O4 phases are examined from the assemblies of Fe O nanoparticles. As revealed by high-resolution...

Electron Beam Lithography

Electron beam lithography in which a beam of electrons, rather than photons, is used as the exposure source has extremely high-resolution capabilities combined with a large depth of focus. To date, it has been mainly used in the production of masks and reticules for optical lithography. But it has also been used in the fabrication of very fine-scale devices for fundamental and device-verification studies, and also in the small-scale production of the specialized very high frequency devices....

Surface Chemistry Of Aluminum Oxide Nanoparticles

Because of its importance as a catalyst, the surface chemistry of aluminum oxide, Al2O3, has been extensively studied over the years. 5,6,13-16 In many of these studies, bulk non-nanocrystalline Al2O3 has been studied. 13-16 More recent work has been done on the surface chemistry of nanocrystalline NC -Al2O3. 5,6,11-17 Carnes 17 has reported a method similar to the preparation of AP-MgO for the preparation of NC-Al2O3. This again involves aerogel preparation as it did with AP-MgO. 17 These...

The Assemblies of NiC and NiO Particle Systems

Powder X-ray diffraction profiles of Fig. 1A clearly show the presence of a majority of fcc Ni, with a small amount of hexagonal Ni3C present from carbon-encapsulated Ni nanoparticles. Additionally, that the hexagonal Ni3C phase is detectable using XRD suggests that the hexagonal Ni3C most likely is one single phase along with majority of fcc Ni phase in these assemblies of Ni C nanoparticles. However, the main reflection peaks of XRD Fig. 1B for pure Ni nanoparticles coated with NiO layers are...

Synthesis Of Semiconductor Nps In The Apoferritin Cavity

Reports of inorganic NP synthesis in the apoferritin cavity have so far mostly been of metal complexes. It is of great interest to explore the possibility of synthesizing compound semiconductor NPs in the apoferritin cavity. Because the electron energy levels of the semiconductor NPs depend on their size and shape, semiconductor NPs can be a quantum dot or photofluorescence marker and are very attractive for nanoelectronics. However, the introduction of oppositely charged ions is very difficult...

Mechanical Synthesis

Mechanical synthesis as a method for producing nano-powders may be divided into two categories mechanical milling and mechanical alloying. Mechanical milling is used both for grinding and amorphization of the starting material. Mechanical alloying requires grinding, mixing, mass transfer, and chemical interaction of powders of several pure elements, compounds, or alloys. Substances in the crystalline and amorphous states may be prepared by mechanical alloying. Mechanical synthesis is the most...

Nanocrystallization During Melt Quenching

As noted in Fig. 4, it is possible to encounter conditions that represent the maximum nucleation rate i.e., the minimum time for the onset of nucleation or the nose of the C curve during continuous cooling. One important requirement to achieve a maximum nucleation density is the removal of potent heterogeneous nucleation sites so that the alloy melt may be cooled to the temperature yielding the maximum nucleation rate without prior crystal formation. For homogeneous nucleation the temperature...

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Fig. 7 Field-emission scanning electron microscope FESEM images of two commercially available nanofiltration membranes with RMS roughness values of A 12.8 nm and B 56.5 nm taken from Ref. 43 . Additional A and B membrane properties include zeta potentials of 18 and 25mV at 10mM and pH 7 , pure water contact angles of 51.9 and 51.7, hydraulic resistances of 3.26 x 1010 and 3.13 x 1010Pa s m, and salt rejections of 35 and 83 at 30 gallons per square foot of membrane per day, gfd, and 10 mM NaCl ,...

Defining NF Separation Performance

When an external pressure is imposed on a liquid adjacent to a nanofiltration membrane, the liquid will flow through the membrane in proportion to the applied pressure. Liquid flow through a NF membrane is described as a solvent flux Jv , which is given by a Darcy-type relation such as in which Apeff is the effective trans-membrane pressure, m is the permeate viscosity, and Rtot is the total hydraulic resistance toward solvent flow. Dissolved solutes also flow toward the membrane by the...

C3

Fig. 1 A and B SEM images illustrating the morphology of melt-spun and ground Pr2Fe14B a-Fe particles, and C and D BF and DF TEM images showing the nanocrystalline 25-30 nm grain size of the starting powders. Fig. 1 A and B SEM images illustrating the morphology of melt-spun and ground Pr2Fe14B a-Fe particles, and C and D BF and DF TEM images showing the nanocrystalline 25-30 nm grain size of the starting powders. Fig. 2 A Schematic illustration of three-capsule plate-impact fixture used for...

Reduced brittleness and enhanced ductility and superplasticity

Superplasticity and ductility refer to the capability of some polycrystalline materials to undergo extensive tensile deformation without necking or fracture. Ceramic brittleness is the biggest technical barrier in practical applications, especially in load-bearing applications. Theoretical and experimental results provide evidence for the possibility that traditional brittle materials can be ductilized by reducing their grain sizes. 1 When made from nanoparticles, brittle ceramics can be...

Microwave Synthesis

Recently, there has been a growing interest in heating and sintering of ceramics by the microwave energy. 48,49 The interest in the use of microwave processing spans a number of fields from food processing to medical applications to chemical applications. A major area of research in microwave processing of ceramics includes microwave material interaction, dielectric measurement, microwave equipment design, new material development, sintering, joining, and modeling. Therefore the microwave...

Zeta Potential For Gold Au

Iff7 106 105 104 103 102 101 Concentration of electrolyte equivalents per liter Fig. 3 Zeta potential profile of a positively charged alumina surface in the presence of various ions. Source From Ref. 3 . covalent bonding with surface atoms or be more physical, e.g., van der Walls forces between the ion and the surface or between the hydrocarbon chains of surfactant ions adsorbed. 3 Isoelectric Point and or Point of Zero Charge Although the isoelectric point iep and the point of zero charge pzc...

M

Fig. 12 Cyclic hardening softening curves of some selected SPD metals with UFG structures. Source From Ref. 33 . Softening is common for cyclic deformation of pre-strained f.c.c. metals. 4,5,51 It has been also clearly observed in many ECAP f.c.c. metals such as cop-perPo-22,26 Ni, 29 single-phase Al-Mg 5056 3031 and Fe-36Ni Invar alloys, 32 and precipitation-hardened Cu0.44Cr0.2Zr alloy. 36 However, the detailed characteristics of cyclic softening, its phenomenology, and microscopic mechanisms...

Motor Proteins In A Synthetic Environment

Controlling the interaction between the motor proteins and the synthetic materials is a major challenge in the A fundamental element in the engineering of biomole-cular motor-powered devices and materials is the ability to modulate the activity of the motors. To date, two strategies have been used to regulate the functionality of biomolecular motors in synthetic systems. The first strategy involved the controlled release of caged ATP into solution to modulate the linear translation of...

Cyclic Softening and Hardening

Fig. 10 Basic cyclic stress-strain curves for several UFG ECAP metals. Fig. 10 Basic cyclic stress-strain curves for several UFG ECAP metals. Fe-36 Ni Invar alloy subjected to different number of ECA pressings between 2 and 12 are approximately the same, i.e., the cyclic strain hardening exponent nb' values are nearly equal for all samples regardless of the preimposed strain. Fig. 11 compares the monotonic and CSSC for ECAP Fe-36 Ni Invar alloy only the initial part of the tensile stress-strain...

Nanoparticle Sensors

The optical and or electrical electrochemical properties of metallic or semiconducting nanoparticles and Fig. 4 Schematic representation of a self-assembling, hydrogen-bonding ferrocene amide capable of electroanalytical anion sensing. With the specific receptors shown, hydrogen phosphate anion recognition cathodic shifts in the ferrocene half-wave potential are gt 290 mV in magnitude greater, to our knowledge, than anything reported to date. Source From Ref. 81 . Fig. 4 Schematic...

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Materials processing by simple shear. Mater. Sci. Eng., A 1995, 197, 157-164. 4. Suresh, S. Fatigue of Materials Cambridge University Press Cambridge, United Kingdom, 1991. 5. Polak, J. Cyclic Plasticity and Low Cycle Fatigue Life of Metals Elsevier The Netherlands, 1991. 6. Valiev, R.Z. Materials science nanomaterial advantage. Nature 2002, 419, 887-889. 7. McFadden, S.X. Mishra, R.S. Valiev, R.Z. Zhilyaev, A.P. Mukherjee, A.K. Low-temperature superplasticity in nanostructured...

Exchangecoupled Nanocomposite Permanent Magnets

One of the most important properties of permanent magnets is the maximum energy product, BH max, which is a measure of the maximum stored energy. In the last 50 years, 1,2 remarkable evolutionary and revolutionary progress made in permanent magnet materials has resulted in the development of AlNiCo's with BH max 8 MGOe, strong rare earth SmCo5 1 5 and Sm Co, Fe, Cu, and Zr z 2 17 with BH max 30 MGOe, and the new R-Fe-B supermagnets, which have large values of magnetization and...

Gmr Head Definition

In 1988, a new magnetoresistive effect was discovered in Germany and France, identified as the giant magne-toresistive GMR effect, using multifilms of chromium and iron synthesized by molecular beam epitaxy. When this Cr Fe structure was tested at liquid helium, cryogenic temperatures in very strong magnetic fields of several thousand Oersteds, or about 100 times greater than what would be obtained from a rotating magnetic media in a disk drive, the result was a resistance change of as much as...

Gouy Chapman diffuse doublelayer model

This is independently known as the Gouy-Chapman model. They expressed that, in addition to the electrostatic attraction of counterions to the charged surface, some of them tend to diffuse toward the bulk solution because of their thermal motion. Note that the EDL theory can be developed for different solid geometries such as flat plate, sphere, and cylinder. Because most studies for organic and inorganic solids in liquids assume the flat plate geometry, 17,18 here we also consider the flat...

Methods Of Zeta Potential Measurements

Electrokinetic measurements using electrophoresis, electroosmosis, streaming potential, and sedimentation potential can be interpreted to yield a quantity known zeta or electrokinetic potential. 3,42 Of these four techniques, the electrophoresis is perhaps the best known and most commonly used technique to measure the zp of minerals. While the electrophoresis technique with modifications is extended for the measurement of very fine particles such as nanoparticles lt 100nm and colloidal...

Preconcentration For Analytical Applications

What we know is typically bound by what we can confidently measure. Consequently, there are ongoing efforts to improve the sensitivity, selectivity, and speed of analytical methods. One approach to improving any analytical method is to separate the analtye s for the sample matrix and concentrate them into a smaller volume prior to measurement. When this preconcen-tration is carried out with small quantities of sorbents, the method is typically referred to as a solid-phase microextraction SPME ....