The use of silicon oxynitride (SiO.sub.x N.sub.y) as a sacrificial material for forming a microelectromechanical (MEM) device is disclosed. Whereas conventional sacrificial materials such as silicon dioxide and silicate glasses are compressively strained, the composition of silicon oxynitride can be selected to be either tensile-strained or substantially-stress-free. Thus, silicon oxynitride can be used in combination with conventional sacrificial materials to limit an accumulation of compressive stress in a MEM device; or alternately the MEM device can be formed entirely with silicon oxynitride. Advantages to be gained from the use of silicon oxynitride as a sacrificial material for a MEM device include the formation of polysilicon members that are substantially free from residual stress, thereby improving the reliability of the MEM device; an ability to form the MEM device with a higher degree of complexity and more layers of structural polysilicon than would be possible using conventional compressively-strained sacrificial materials; and improved manufacturability resulting from the elimination of wafer distortion that can arise from an excess of accumulated stress in conventional sacrificial materials. The present invention is useful for forming many different types of MEM devices including accelerometers, sensors, motors, switches, coded locks, and flow-control devices, with or without integrated electronic circuitry.

Partial burnt off process of sacrificial material while fabricating porous electrode for gas sensors and fuel cells brings uncertainties about reaction of gas species with remained sacrificial material. Here, efforts were devoted to fabricate a porous electrode with high electrical conductivity without using sacrificial carbon material. To do so, bilayers of Pt/Pd were deposited over Yttria Stabilized Zirconia substrate and thermally treated at 500^oC for different annealing times. As a result of annealing, solid state interdiffusion between Pt and Pd was activated resulting to generation of Pd accompanied with pores on the surface of Pt layer. Moreover, 10min annealing leads to higher electrical conductivity of intermixed layer which is most probably due to a reduction in grain boundary r...

Methods of forming aluminum oxynitride (AlON) materials include sintering green bodies comprising aluminum orthophosphate or another sacrificial material therein. Such green bodies may comprise aluminum, oxygen, and nitrogen in addition to the aluminum orthophosphate. For example, the green bodies may include a mixture of aluminum oxide, aluminum nitride, and aluminum orthophosphate or another sacrificial material. Additional methods of forming aluminum oxynitride (AlON) materials include sintering a green body including a sacrificial material therein, using the sacrificial material to form pores in the green body during sintering, and infiltrating the pores formed in the green body with a liquid infiltrant during sintering. Bodies are formed using such methods.

Purpose - In microfluidic channel fabrication in low temperature co-fired ceramics (LTCC), one of the biggest challenges is the elimination of channel deformation during lamination. The purpose of this paper is to describe the expected deformation of the substrate and the sacrificial layer (starch powder and 3D printed UV polymerized material) during the lamination process of microfluidic structure fabrication. Design/methodology/approach - Uniaxial compression and Jenike shear test were used to obtain the mechanical parameters of starch sacrificial volume material (SVM). To determine the stress-strain characteristics of LTCC a uniaxial compression experiment was conducted. The shape of the laminated LTCC containing embedded channel was modeled by finite element method using the mechanical...

Selection of candidate materials and processes for manufacturing structural members is of great moment in designing surface micromechanics devices. The known arts of obtaining superficial microstructures, as a rule, with the use of a 'sacrificial' layer were based on the employment of polysilicon as a working material and of silicon dioxide as a removable 'sacrificial' underlayer. This paper proposed an art for obtaining a novel structure forming the basis for surface micromechanics. Thereby monocrystalline silicon carbide is to be epitaxially grown over a compound substrate, such as AlN-Si, AlN-Al2O3 or AlN-SiC. A film of aluminium nitride serves then as an orientation base for epitaxially-grown silicon carbide and also as a 'sacrificial' layer to be stripped away by an etchant which must be non-reactive both to SiC and to substrate material. The crystallochemical computability of SiC and AlN, their matching thermal expansion coefficients, and high mechanical properties of silicon carbide favor a stress decrease in movable loaded members of surface micromechanics devices, just increasing those performance stability. The paper will present some experimental results that have been obtained in designing a process for manufacturing a rotating wheel vibratory microgyroscope with a moveable SiC pendulum using a SiC-AlN composition as the base.

We have studied the properties of photoresist (resist) as a sacrificial material for fabricating suspended metal bridges and developed a process to release RF MEMS switches by dissolving thermal cross-linked extra hard photoresist. At the edges of the patterned photoresist, the contact angle with the substrate can be tuned using hard-baking parameters. From the experiment we have found that the resist angle reduces both with baking temperature and time. The baking temperature has a stronger effect on resist slope than the baking time has. It is also observed that at a certain baking temperature, and after a certain time, the resist angle does not reduce further. The RF MEMS switch with photoresist as the sacrificial layer can be released by plasma ashing to strip the initial resist skin, f...

External renders based on air lime are used in historical buildings as decorative and protective coats. They act as sacrificial layers, particularly exposed to climatic actions and mechanical and environmental impact. They generally present good cohesion and adhesion to the background, although often suffer some degradation as detachments, superficial cracks, or 'lacunae'. Render solutions specified today for old buildings repair are frequently incompatible with pre-existent materials and inappropriate for the specific situation, thus producing new pathology. The choice of adequate materials, formulation, and curing conditions of substitution mortars become crucial for the success of the conservation action. These mortars must meet functional and aesthetic requirements, to fulfill the prin...

These solid electrolytes are single-ion conductors. NASA's Jet ..... dene fluoride) in N-methyl-2-pyrrolidi- none. .... Sacrificial nanowires are buried, then etched away to form buried channels. ... ferred onto the SiO2 layer by reactive-ion etching ...

This process combines the best features of bulk ad surface micromachining. It enables the production of stress free, thick, virtually arbitrarily shaped structures with well defiti thick or thin sacrificial layers, high sacrificial layer selectivity and large undercuts using IC compatible, processes. The basis of this approach is the use of dy available {111} oriented substrates. anisotropic Si trench etching, S iN masking and KOH etching.

A method is disclosed for integrating one or more microelectromechanical (MEM) devices with electronic circuitry on a common substrate. The MEM device can be fabricated within a substrate cavity and encapsulated with a sacrificial material. This allows the MEM device to be annealed and the substrate planarized prior to forming electronic circuitry on the substrate using a series of standard processing steps. After fabrication of the electronic circuitry, the electronic circuitry can be protected by a two-ply protection layer of titanium nitride (TiN) and tungsten (W) during an etch release process whereby the MEM device is released for operation by etching away a portion of a sacrificial material (e.g. silicon dioxide or a silicate glass) that encapsulates the MEM device. The etch release process is preferably performed using a mixture of hydrofluoric acid (HF) and hydrochloric acid (HCI) which reduces the time for releasing the MEM device compared to use of a buffered oxide etchant. After release of the MEM device, the TiN:W protection layer can be removed with a peroxide-based etchant without damaging the electronic circuitry.

We propose a new fabrication process of nano-gap electrode pairs using an atomic-layer-deposited (ALD) sacrificial layer and the shadow deposition technique. In this process, gap width can be precisely controlled by the number of deposition cycles of the ALD process, whereas junction area is defined by the deposition angle of the second electrode material through an overhanging shadow mask on top of the first electrode. In comparison with our previous method, process reliability has been highly improved because the unintentional deposition of the second electrode material on the sidewall of the first electrode is completely prevented. We have fabricated 10×10 arrays of n-type polycrystalline silicon (n-poly-Si)/Au nano-gap electrode pairs with gap widths of 6 and 9 nm, which show good insulating properties at room temperature.   

Polyhedral oligomeric silsesquioxane (POSS) based materials hold great promise for developing a photopatternable low-k material which eliminates the need for sacrificial layers when patterning low-k dielectric films. In this work we demonstrate that organic materials based on partially fluorinated, polyhedral oligomeric silsesquioxane (POSS) functionalized (meth)acrylates (POSS-F) containing appropriate amounts of the photoacid generator (PAG), triphenylsulfonium perfluorooctylsulfonate (TPS-PFOS), in order to achieve positive tone imaging, present ultra low k- values (lower than 2.0) which further decrease when the amount of the photoacid generator increases due to the large percentage of C-F bonds in the selected PAG. A concentration of about 5% w/w of the photo-acid generator was found ...

We present a novel type of all-aqueous non-ionic layer-by-layer films of silk fibroin with synthetic macromolecules and a natural polyphenol. We found the multilayer growth and stability to be strongly pH-dependent. Silk assembled with poly(methacrylic) and tannic acids at pH=3.5 disintegrated at pH~5; while silk/poly(N-vinylcaprolactam) interactions were stable at low and high pH values but resulting in thinner films at high pH. The results suggest that the intermolecular interactions are primary driven by hydrogen bonding with a considerable contribution of hydrophobic forces. We also demonstrated that cubical, spherical and platelet capsules with silk-containing walls can be constructed using particulate sacrificial templates. This work sets a foundation for future explorations of natural and synthetic macromolecules assemblies as biomimetic materials with tunable properties. PMID:22432092

A new process derived from screen-printing technology and based on thick sacrificial layers has been developed in our laboratory for the fabrication of films partially released from the substrate. The sacrificial layer acts as a stable mechanical support during the firing of the active layer and is totally removed after the final thermal treatment of the sample. Fabrication of a copper electrothermal actuator was undertaken to demonstrate the efficiency of this simple, collective and low cost process. Passive components based on this new process include the fabrication of heating resistors, strain gauges and microchannels. Moreover, the process can also be used to facilitate the implementation of piezoelectric devices.

A process for forming one or more fluid microchannels on a substrate is disclosed that is compatible with the formation of integrated circuitry on the substrate. The microchannels can be formed below an upper surface of the substrate, above the upper surface, or both. The microchannels are formed by depositing a covering layer of silicon oxynitride over a mold formed of a sacrificial material such as photoresist which can later be removed. The silicon oxynitride is deposited at a low temperature (.ltoreq.100.degree. C.) and preferably near room temperature using a high-density plasma (e.g. an electron-cyclotron resonance plasma or an inductively-coupled plasma). In some embodiments of the present invention, the microchannels can be completely lined with silicon oxynitride to present a uniform material composition to a fluid therein. The present invention has applications for forming microchannels for use in chromatography and electrophoresis. Additionally, the microchannels can be used for electrokinetic pumping, or for localized or global substrate cooling.

Terrorist bombings are a dismal reality nowadays. One of the most effective ways for protection against blast overpressure is the use of lightly compacted materials such as sand [1] and aqueous foam [2] as a protective envelope or barrier. According to [1], shock wave attenuation in a mine tunnel (one-dimensional case) behind a destroyed object is given by q_e ? q {1}/{1 + 4(S/q)^{1/6} b? _{mat} /L^{1/3} }where qe — effective charge, S — exposed area of the obstacle, q — TNT equivalent (grams), L — distance between charge and obstacle, b — obstacle thickness and ? mat — material density. This empirical equation is applicable only in a one-dimensional case but not for a less confined environment. Another way of protecting a structure against blast is to coat the surface with a sacrificial layer. In [3] full-scale experiments were carried out to investigate the behaviour of a covering of aluminum foam under the effect of a blast wave.

The processing and application of graphite powder-based sacrificial layer for fabrication of microfluidic structures in LTCC is described. Such layers are produced as pastes, which are screen-printed in LTCC sheets to avoid sagging, by supporting closed, three-dimensional structures such as chann...

Polymer Shape Deposition Manufacturing is a new Solid Freeform. Fabrication process. Shape Deposition Manufacturing (SDM) is a layered manufacturing process involving an iterative combination of material addition and material removal using a part material and a sacrificial support material. Polymer SDM uses such techniques to build polymer parts. In this research, new material combinations were identified, material strength was characterized, and several applications were identified. The constraints on Polymer SDM part and sacrificial support materials were identified, and a variety of compatible material combinations were developed. Ultraviolet-curing part and support materials and fast-curing polyurethane part materials were developed to reduce cycle times. Solvent-removable support materials for use with castable thermoset part materials were developed. Epoxy and polyurethane materials with improved interlayer bonding were identified. Polymer SDM part strength is determined both by the bulk material properties of the part materials and by their interlayer bonding. Tensile strengths of three thermoset part materials were measured. Both monolithic specimens and specimens with two interlayer interfaces were tested. Interlayer strengths ranged from 5--40 MPa. Relative interface strengths varied even between similar materials; such differences may be explained by surface wetting and polymer chain interpenetration. There are many applications for the Polymer SDM process. Mechanisms with moving parts and small clearances can be built already assembled, and objects can be embedded within parts. The Polymer SDM process was compared to commercial rapid prototyping technologies. Polymer SDM can build parts with superior surface finish and comparable strength but has more flexibility for construction of mechanisms and parts with embedded objects. Polymer SDM can also be used to construct fugitive wax molds for casting other materials. This technique, called "Mold SDM," was developed by other researchers at Stanford using materials identified during the present research. This indirect process allows the use of a wider variety of part materials, and produces monolithic finished parts which are stronger since they lack interlayer interfaces. Comparison parts were made using both the Polymer SDM and the Mold SDM methods. M and the Mold SDM methods.

Silicon is currently the most commonly used material for the fabrication of microelectromechanical systems (MEMS). However, silicon-based MEMS will not be suitable for long-endurance devices involving components rotating at high speed, where friction and wear need to be minimized, components such as 2-D cantilevers that may be subjected to very large flexural displacements, where stiction is a problem, or components that will be exposed to corrosive environments. The mechanical, thermal, chemical, and tribological properties of diamond make it an ideal material for the fabrication of long-endurance MEMS components. Cost-effective fabrication of these components could in principle be achieved by coating Si with diamond films and using conventional lithographic patterning methods in conjunction with e. g. sacrificial Ti or SiO{sub 2} layers. However, diamond coatings grown by conventional chemical vapor deposition (CVD) methods exhibit a coarse-grained structure that prevents high-resolution patterning, or a fine-grained microstructure with a significant amount of intergranular non-diamond carbon. The authors demonstrate here the fabrication of 2-D and 3-D phase-pure ultrananocrystalline diamond (UNCD) MEMS components by coating Si with UNCD films, coupled with lithographic patterning methods involving sacrificial release layers. UNCD films are grown by microwave plasma CVD using C{sub 60}-Ar or CH{sub 4}-Ar gas mixtures, which result in films that have 3--5 nm grain size, are 10--20 times smoother than conventionally grown diamond films, are extremely resistant to corrosive environments, and are predicted to have a brittle fracture strength similar to that of single crystal diamond.

Our paper presents a non-destructive thermal transient measurement method that is able to reveal differences even in the micron size range of MEMS structures. Devices of the same design can have differences in their sacrificial layers as consequence of the differences in their manufacturing processe...

The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at ...

A sacrificial layer must be removed in order to release a freestanding structure from a substrate. Adhesion of a freestanding structure to a substrate often occurs in the release process. A new sacrificial layer process is developed in order to reduce the adhesion. A photoresist film is used as a sacrificial layer and micromachine structures are fabricated by Ni electroplating. Before fabricating a freestanding structure, the photoresist film is exposed in order to retain small columns after development. The release process consists of the following two steps. First, the sacrificial layer is removed by a conventional wet development. The freestanding structures are supported by small resist columns. Next, the small resist columns are removed by O2 plasma. Since only the small resist area is removed by plasma ashing, the ashing time can be reduced to 1/4 of that required for the entire resist area ashing. A cantilever beam of 750 ?m length can be fabricated without adhesion by the new process. The fabricated cantilevers can be vibrated by applying a sinusoidal voltage. The resonant frequency of the 750-?m-long cantilever is 21 kHz. The resonant frequencies of the cantilever of various beam lengths are examined.   

Damages are created in a sacrificial layer of silicon dioxide by ion implantation to enhance the etch rate of silicon-dioxide in liquid and vapor phase hydrofluoric acid. The etch rate ratio between implanted and unimplanted silicon dioxide is more than 150 in vapor hydrofluoric acid (VHF). This fea...

Gap fill materials and planar-type bottom antireflective coating are needed for patterning metal trenches in the via-first dual damascene process. We have already reported on thermal cross-link gap fill materials and bottom antireflective coating as planarizing layers under a resist that can be spin-coated and etched faster than resists. In this study, developer-soluble gap fill materials were optimized in order to obtain excellent planarization, simplify the process, and increase wafer throughput. The developer-soluble gap fill materials using poly(4-hydroxystyrene) derivatives developed by an approach of the via-first dual damascene process was obtained by optimizing the concentration of the phenol group with solubility in the alkaline developer (0.26 N tetramethylammonium hydroxide, TMAH) and by thermal cross-link reaction. In addition to a superior via-filling performance, developer-soluble gap fill materials using poly(4-hydroxystyrene) derivatives showed a wide process window of prebake temperature, the controllable dissolution rate for the etch-back process, and a good CF4 etch rate of 1.4 times higher than that of a resist for etching the substrate. These results were attributed to the polymer structures of poly(4-hydroxystyrene) derivatives. Both dry plasma cleaning and wet developer cleaning can be used to remove residual gap fill materials after processing. This novel approach using developer-soluble gap fill materials as a new type of sacrificial material in an advanced lithography process makes this solution convenient for planarizing surfaces and is economically favorable owing to high throughput.

In this work, 3D structuration of LTCC (low-temperature co-fired ceramic) for microfluidics was studied, using two novel sacrificial carbon paste compositions. These pastes are based on graphite with a water-soluble vehicle consisting of polyvinylpyrrolidone binder (PVP) dissolved in propylene glycol (PG), which is not aggressive to green LTCC material. Both examined pastes differ slightly in binder content and added plasticizer, glycerol (G) or trimethylolpropane (TMP). The thermal properties of the sacrificial carbon pastes have been examined using combined thermo-gravimetric analysis (TGA), differential thermal analysis (DTA) and differential thermo-gravimetry (DTG). The sacrificial carbon pastes have been applied to the fabrication of membranes and microchannels in LTCC substrate. A co...

Hollow carbon nanofibers (HCNFs) were successfully manufactured by co-axial (core/shell) electrospinning of poly(styrene-co-acrylonitrile) (SAN) and poly(acrylonitrile) (PAN) solutions. The shell component (PAN) was converted into a turbostratic carbon structure by thermal treatment, whereas the sacrificial core component (SAN) was eliminated. SAN was found to be a very suitable material for the sacrificial core. SAN exhibited excellent co-axial electrospinnability to produce a uniform core/shell nanofiber precursor because of its immiscibility with PAN. Also, SAN had a good thermal sustainability that prevented the PAN shell from shrinking during the stabilization and carbonization processes, thus maintaining the shell structure. These two predominant properties of SAN enabled the manufac...

PDMS is a widely used material for construction of microfluidic devices. The traditional PDMS microfabrication process, although versatile, cannot be used to form microfluidic devices with embedded tall topological features, such as thick-film electrodes and porous reactor beds. This paper presents an elegant surface micromachining process for microfluidic devices that allows complete leak-proof sealing and a conformal contact of the PDMS with tall pre-existing topographical features and demonstrates this approach by embedding 6 µm thick Ag/AgCl (high capacity 1680 µA s) electrodes inside the microchannels. In this process, thin spin-cast films of the PDMS are used as the structural material and a photoresist is used as the sacrificial material. A crucial parameter, namely adhesion of the spun-cast structural layer to the substrate, was characterized for different pre-polymer ratios using a standard tensile test, and a 1:3 (curing agent:base) combination was found to be the best with a maximum adhesion strength of 7.2 MPa. The elastic property of the PDMS allowed extremely fast release times of ~1 min of the fabricated microchannels. The versatility of this process was demonstrated by the fabrication of a pneumatic microvalve with multi-layered microchannel geometry. The valve closure occurred at 6.37 kPa. Preliminary results of this paper have been presented at the Canadian Workshop on MEMS and Microfluidics, Montréal, Canada, August 2007.

Composite, lightweight sacrificial tip with graphite designed reduces lightning-strike damage to composite parts of aircraft and dissipates harmful electrical energy. Device consists of slender composite rod fabricated from highly-conductive unidirectional reinforcing fibers in matrix material. Rods strategically installed in trailing edges of aircraft wings, tails, winglets, control surfaces, and rearward-most portion of aft fuselage.

The formation mechanism of microchannels with Fe-Cu alloy lining layers in iron bodies produced by a powder-metallurgical microchanneling process has been investigated. Copper wire was used as a sacrificial core that gives the shape of the microchannel and supplies the alloying element for the lining layer. An iron powder compact containing the sacrificial core was heated and sintered at temperatures between the melting points of copper and iron. Quenching experiments showed that the microchannel was produced just after melting of copper. In a quenched specimen with a newly-formed microchannel, fine copper-rich regions were observed between the iron powder particles in the lining layer. These results established that infiltration of molten copper into the iron powder is the dominant mechanism for the Fe-Cu microchanneling process. It was also found that the liquid copper infiltrated via preferential flow pathways between the iron powder particles.   

Layered compaction manufacturing (LCM), which is a hybrid process of powder compaction and milling in layers, is applied to the fabrication of a cemented carbide mold (WC–9 mass%Co) for the forming of optical glass lenses with internal cooling channels, which are placed along the molding cavity. The mold is produced by repeating the process of powder compaction with the subsequent creation of grooves filled with paraffin wax as a sacrificial material. The channels placed along the molding cavity are formed during the sintering process by dewaxing. In the sintering process, the extent of deformation in the shape of the internal channels and molding cavity is measured. It is found that the shapes of the channels and cavity exhibit uniform linear shrinkage in the range from 17 to 19%. By filling the molding cavity with epoxy resin, the cooling capability of the mold by air is investigated by performing experiments as well as two-dimensional finite differences simulation. The cooling effect of the mold in the glass lens-forming process is also estimated by the simulation. For both resin and glass, when air is supplied to the channels, the obtained cooling rate is approximately ten times higher as compared to natural cooling at an ambient temperature.   

The local formation of porous anodic alumina (PAA) thin films on confined areas measuring few {mu}m{sup 2} through an SiO{sub 2} masking layer on the silicon substrate has been developed. The locally grown porous anodic alumina thin films showed highly symmetric vertical cylindrical pores with a pore density that was much higher than that of films on non-confined areas. Pore density as high as 6 x 10{sup 10} pores/cm{sup 2} was achieved, compared to {proportional_to}10{sup 10} pores/cm{sup 2} in corresponding large-area samples. Pore diameter was as small as 30-50 nm. Alumina thin films on confined areas on a Si substrate are very interesting for use as masking layers for local Si nanopatterning or as templates for local growth of different nanostructures, e.g. nanowires of different materials, on wafer level. In this work, we used the PAA films as sacrificial templates to grow locally on a silicon wafer using sputtering, regular arrays of Ti nanopillars on pre-selected areas on the Si wafer. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

This work describes the design and micromachining of all-SU-8 structures for a bio-mimetic flying micro-air-vehicle. The design based on simple analytical and finite-element model was briefly discussed to understand and optimize the structural sizes. The micromachining was improved from our previous works, utilizing a new process featuring ultra-thick AZ 4562 sacrificial layers. To obtain a large wing displacement, the process was improved to double the gap and to compare with our previous work. A sacrificial layer of thickness up to 90mm was realized by a single coating, exposure and development. The gap between the ring and the beam at wing root was enhanced to 120mm. As-prepared structures can generate a flapping angle of 40-70degree, which depends on morphologic and geometric details o...

The current research is focused on processing ceramic foams with compositions that have potential as a thermal protection material. The use of pre-ceramic polymers with the addition of sacrificial blowing agents or sacrificial fillers offers a viable approach to form either open or closed cell insulation. Our work demonstrates that this is a feasible method to form refractory ceramic foams at relatively low processing temperatures. It is possible to foam complex shapes then pyrolize the system to form a ceramic while retaining the shape of the unfired foam. Initial work focused on identifying suitable pre-ceramic polymers with desired properties such as ceramic yield and chemical make up of the pyrolysis product after firing. We focused on making foams in the Si system (Sic, Si02, Si-0-C), which is in use in current acreage TPS systems. Ceramic foams with different architectures were formed from the pyrolysis of pre-ceramic polymers at 1200 C in different atmospheres. In some systems a sacrificial polyurethane was used as the blowing agent. We have also processed foams using sacrificial fillers to introduce controlled cell sizes. Each sacrificial filler or blowing agent leads to a unique morphology. The effect of different fillers on foam morphologies and the characterization of these foams in terms of mechanical and thermal properties are presented. We have conducted preliminary arc jet testing on selected foams with the materials being exposed to typical re-entry conditions for acreage TPS and these results will be discussed. Foams processed using these approaches have bulk densities ranging from 0.15 to 0.9 g/cm3 and cell sizes ranging from 5 to 500 pm. Compression strengths ranged from 2 to 7 MPa for these systems. Finally, preliminary oxidation studies have been conducted on selected systems and will be discussed.

In this work, carbon nanotubes (CNTs) were deposited in a triode structure by electrophoretic deposition (EPD). Two power supplies were used in order to provide a gate electrode and a cathode electrode with different voltages. Following the electric field distribution, CNTs were forcibly dragged toward the cathode electrode but repelled out of the gate electrode. By this designed voltage-controlling method, CNTs were deposited in the selected area without any photoresist or sacrificial layer.   

A three-layer oxynitride Ruddlesden Popper phase Rb1+xCa2Nb3O10-xNx·yH2O (x=0.7 0.8, y=0.4 0.6) was synthesized by ammonialysis at 800 °C from the Dion Jacobson phase RbCa2Nb3O10 in the presence of Rb2CO3. Incorporation of nitrogen into the layer perovskite structure was confirmed by XPS, combustion analysis, and MAS NMR. The water content was determined by thermal gravimetric analysis and the rubidium content by ICP-MS. A similar layered perovskite interconversion occurred in the two-layer Dion Jacobson oxide RbLaNb2O7 to yield Rb1+xLaNb2O7-xNx·yH2O (x=0.7 0.8, y=0.5 1.0). Both compounds were air- and moisture-sensitive, with rapid loss of nitrogen by oxidation and hydrolysis reactions. The structure of the three-layer oxynitride Rb1.7Ca2Nb3O9.3N0.7·0.5H2O was solved in space group P4/mmm with a=3.887(3) and c=18.65(1)Å, by Rietveld refinement of X-ray powder diffraction data. The two-layer oxynitride structure Rb1.8LaNb2O6.3N0.7·1.0H2O was also determined in space group P4/mmm with a=3.934(2) and c=14.697(2)Å. GSAS refinement of synchrotron X-ray powder diffraction data showed that the water molecules were intercalated between a double layer of Rb+ ions in both the two- and three-layer Ruddlesden Popper structures. Optical band gaps were measured by diffuse reflectance UV-vis for both materials. An indirect band gap of 2.51 eV and a direct band gap of 2.99 eV were found for the three-layer compound, while an indirect band gap of 2.29 eV and a direct band gap of 2.84 eV were measured for the two-layer compound. Photocatalytic activity tests of the three-layer compound under 380 nm pass filtered light with AgNO3 as a sacrificial electron acceptor gave a quantum yield of 0.025% for oxygen evolution.

New epoxy based sol-gel organic inorganic materials, showing lithographic resist-like properties without the addition of any photocatalysts, are presented. To obtain a material sensitive to radiation, specific sol-gel syntheses based on an organically modified alkoxide containing an epoxy ring, 3-glycidoxypropyltrimethoxysilane (GPTMS), have been developed. The synthesis and the patternability of hybrid materials have been obtained controlling the inorganic crosslinking degree and with an almost total absence of organic polymerization. Two examples of directly patternable hybrid films, called GB and GGe, have been synthesized using acidic (GGe) and basic (GB) conditions and obtaining different compositions. After electron beam lithography (EBL) or x-ray synchrotron radiation lithography (XRL) the polymerization of the organic component of the sol-gel film occurs, generating a hardening of the structure after post-exposure baking. The exposed polymerized material becomes insoluble, determining a negative resist-like behaviour of the film: the lithographic process of nanopatterning results from the dissolution of the unexposed areas in proper solvents (developers). Spatial resolution of the order of 200 nm is reported and a contrast of 2.2 is achieved. The novelty of this work is that epoxy based materials, which have enhanced thermomechanical stability with respect to the more usual acrylic based resins, are directly nanopatterned for the first time by electron beam (EB) and/or x-ray beam radiation exposure without the aid of catalysts for polymerization. In contrast to common resists that are sacrificial layers of the fabrication process, direct patternable sol-gel hybrids constitute the final material of the devices. In fact, an example of doping with a light emitting dye is reported together with the achievement of directly patterned structures by EBL and XRL.

New epoxy based sol-gel organic inorganic materials, showing lithographic resist-like properties without the addition of any photocatalysts, are presented. To obtain a material sensitive to radiation, specific sol-gel syntheses based on an organically modified alkoxide containing an epoxy ring, 3-glycidoxypropyltrimethoxysilane (GPTMS), have been developed. The synthesis and the patternability of hybrid materials have been obtained controlling the inorganic crosslinking degree and with an almost total absence of organic polymerization. Two examples of directly patternable hybrid films, called GB and GGe, have been synthesized using acidic (GGe) and basic (GB) conditions and obtaining different compositions. After electron beam lithography (EBL) or x-ray synchrotron radiation lithography (XRL) the polymerization of the organic component of the sol-gel film occurs, generating a hardening of the structure after post-exposure baking. The exposed polymerized material becomes insoluble, determining a negative resist-like behaviour of the film: the lithographic process of nanopatterning results from the dissolution of the unexposed areas in proper solvents (developers). Spatial resolution of the order of 200 nm is reported and a contrast of 2.2 is achieved. The novelty of this work is that epoxy based materials, which have enhanced thermomechanical stability with respect to the more usual acrylic based resins, are directly nanopatterned for the first time by electron beam (EB) and/or x-ray beam radiation exposure without the aid of catalysts for polymerization. In contrast to common resists that are sacrificial layers of the fabrication process, direct patternable sol-gel hybrids constitute the final material of the devices. In fact, an example of doping with a light emitting dye is reported together with the achievement of directly patterned structures by EBL and XRL. PMID:21825670

Abstract A new kind of SnO2 nanotubes loaded with Ag2O nanoparticles can be synthesized by using Ag@C coaxial nanocables as sacrificial templates. The composition of silver in SnO2 nanotubes can be controlled by tuning the compositions of metallic Ag in Ag@C sacrificial templates, and the morphology of tubular structures can be changed by use of nanocables with different thicknesses of carbonaceous layer. This simple strategy is expected to be extended for the fabrication of similar metal-oxide doped nanotubes using different nanocable templates. In contrast to SnO2@Ag@C nanocables as well as to other types of SnO2 reported previously, the Ag2O-doped SnO2 nanotubes exhibit excellent gas sensing behaviors. The dynamic transients of the sensors demonstrated both their ultra-fast response (1-...

Room-temperature synthesis of porous SiO{sub 2} is achieved using a novel PECVD procedure. Porosity of the films is found to directly correlate with the thickness of a sacrificial polymer layer which is removed during the deposition of the oxide thin film. Films prepared with this method are transparent with low refractive index and are very well suited for antireflective coatings and other related optical applications. Membrane-like layers can also be prepared by this method. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

The performance of electrocoagulation (EC) technique for decolorization and chemical oxygen demand (COD) reduction of anaerobically pretreated poultry manure wastewater was investigated in a laboratory batch study. Two identical 15.7-L up-flow anaerobic sludge blanket (UASB) reactors were first run under various organic and hydraulic loading conditions for 216 days. Effects of operating parameters such as type of sacrificial electrode material, time of electrolysis, current density, initial pH, and electrolyte concentration were further studied to optimize conditions for the post-treatment of UASB pretreated poultry manure wastewater. Preliminary tests conducted with two types of sacrificial electrodes (Al and Fe) resulted that Al electrodes were found to be more effective for both COD and...

Aluminum nitride (AlN) is a promising material for a number of applications due to its temperature and chemical stability. Furthermore, AlN maintains its piezoelectric properties at higher temperatures than more commonly used materials, such as Lead Zirconate Titanate (PZT) [1, 2], making AlN attractive for high temperature micro and nanoelectromechanical (MEMs and NEMs) applications including, but not limited to, high temperature sensors and actuators, micro-channels for fuel cell applications, and micromechanical resonators. This work presents a novel AlN micro-channel fabrication technique using Metal Organic Vapor Phase Epitaxy (MOVPE). AlN easily nucleates on dielectric surfaces due to the large sticking coefficient and short diffusion length of the aluminum species resulting in a high quality polycrystalline growth on typical mask materials, such as silicon dioxide and silicon nitride [3,4]. The fabrication process introduced involves partially masking a substrate with a silicon dioxide striped pattern and then growing AlN via MOVPE simultaneously on the dielectric mask and exposed substrate. A buffered oxide etch is then used to remove the underlying silicon dioxide and leave a free standing AlN micro-channel. The width of the channel has been varied from 5 ìm to 110 ìm and the height of the air gap from 130 nm to 800 nm indicating the stability of the structure. Furthermore, this versatile process has been performed on (111) silicon, c-plane sapphire, and gallium nitride epilayers on sapphire substrates. Reflection High Energy Electron Diffraction (RHEED), Atomic Force Microscopy (AFM), and Raman measurements have been taken on channels grown on each substrate and indicate that the substrate is influencing the growth of the AlN micro-channels on the SiO2 sacrificial layer.

Penetration deformation of columnar prismatic enamel was investigated using instrumented nanoindentation testing, carried out at three constant strain rates (0.05 s{sup -1}, 0.005 s{sup -1}, and 0.0005 s{sup -1}). Enamel demonstrated better resistance to penetration deformation and greater elastic modulus values were measured at higher strain rates. The origin of the rate-dependent deformation was rationalized to be the shear deformation of nanoscale protein matrix surrounding each hydroxyapatite crystal rods. And the shear modulus of protein matrix was shown to depend on strain rate in a format: G{sub p} = 0.213 + 0.021 ln {dot {var_epsilon}}. Most biological composites compromise reinforcement mineral components and an organic matrix. They are generally partitioned into multi-level to form hierarchical structures that have supreme resistance to crack growth [1]. The molecular mechanistic origin of toughness is associated with the 'sacrificial chains' between the individual sub-domains in a protein molecule [2]. As the protein molecule is stretched, these 'sacrificial chains' break to protect its backbone and dissipate energy [3]. Such fresh insights are providing new momentum toward updating our understanding of biological materials [4]. Prismatic enamel in teeth is one such material. Prismatic microstructure is frequently observed in the surface layers of many biological materials, as exemplified in mollusk shells [5] and teeth [6]. It is a naturally optimized microstructure to bear impact loading and penetration deformation. In teeth, the columnar prismatic enamel provides mechanical and chemical protection for the relatively soft dentin layer. Its mechanical behavior and reliability are extremely important to ensure normal tooth function and human health. Since enamel generally contains up to 95% hydroxyapatite (HAP) crystals and less than 5% protein matrix, it is commonly believed to be a weak and brittle material with little resistance to fracture [7]. This study is aimed at exploring the effect of the weak amelogenin-rich protein matrix on the overall mechanical behavior of prismatic enamel. The experimental work involves applying contact loads at various strain rates to carefully prepared enamel specimens using an instrumented nanoindentater. The enamel material and specimen preparation procedure were described in a previous study [8]. Briefly, the enamel was dissected into small blocks about 2 mm wide and 1 mm thick. These small blocks had relatively flat surfaces, under which the prisms were uniformly perpendicular to the top surfaces for nanoindentation testing [9,10]. The small blocks were then embedded, ground, and finishing polished with 0.03 {micro}m diamond suspension. Nanoindentation testing was carried out in a MTS XP{reg_sign} nanoindenter (MTS nano instrument, Oak Ridge, TN). Each test consisted of three segments, including a loading process, a holding period at the maximum load for a certain time, and a final unloading process. The loading process was carried out under constant strain rbate [11] to reach a defined penetration depth, corresponding to which the maximum load was reached.

We employed a newly developed anhydrous HF gas-phase etching (GPE) process for the removal of sacrificial oxides. The structural layers are P-doped multi-stacked polysilicon and silicon-on-insulator (SOI) substrates and sacrificial layers are chemical vapor deposition (CVD) tetraethylorthosilicate (TEOS) oxide, low-temperature oxide (LTO), phosphosilicate glass (PSG), and thermal oxides on silicon nitride or polysilicon substrates. The characteristics of residues on polysilicon or silicon nitride were scrutinized by scanning electron microscopy (SEM) and Auger electron spectroscopy (AES). After the GPE of CVD TEOS oxide, LTO, and PSG on the silicon nitride substrate, the polysilicon microstructures adhere to the underlying substrate because neither the SiOxNy layers nor the H3PO4(H2O) layer vaporize. We found that the etching of CVD TEOS oxide, LTO, and thermal oxide on a polysilicon substrate shows no residue and no stiction. Finally, the fabricated microstructures, symmetrically stacked to 6 ?m thickness, operated at DC 4 V and AC 0.1 V in a vacuum chamber at 100 mTorr.   

The National Ignition Facility (NIF) is a 192 beam Nd-glass laser facility presently under construction at Lawrence Livermore National Laboratory (LLNL) for performing inertial confinement fusion (ICF) and experiments studying high energy density (HED) science. When completed in 2009, NIF will be able to produce 1.8 MJ, 500 TW of ultraviolet light for target experiments that will create conditions of extreme temperatures (>10{sup 8} K), pressures (10 GBar) and matter densities (>100 g/cm{sup 3}). A detailed program called the National Ignition Campaign (NIC) has been developed to enable ignition experiments in 2010, with the goal of producing fusion ignition and burn of a deuterium-tritium (DT) fuel mixture in millimeter-scale target capsules. The first of the target experiments leading up to these ignition shots will begin in 2008. The targets for the NIC are both complex and precise, and are extraordinarily demanding in materials fabrication, machining, assembly, cryogenics and characterization. The DT fuel is contained in a 2-millimeter diameter graded copper/beryllium or CH shell. The 75mm thick cryogenic ice DT fuel layer is formed to sub-micron uniformity at a temperature of approximately 18 Kelvin. The capsule and its fuel layer sit at the center of a gold/depleted uranium 'cocktail' hohlraum. Researchers at LLNL have teamed with colleagues at General Atomics to lead the development of the technologies, engineering design and manufacturing infrastructure necessary to produce these demanding targets. We are also collaborating with colleagues at the Laboratory for Laser Energetics (LLE) at the University of Rochester in DT layering, and at Fraunhofer in Germany in nano-crystalline diamond as an alternate ablator to Beryllium and CH. The Beryllium capsules and cocktail hohlraums are made by physical vapor deposition onto sacrificial mandrels. These coatings must have high density (low porosity), uniform microstructure, low oxygen content and low permeability. The ablator capsule has a 5 mm diameter hole laser drilled to permit removal of the mandrel and introduction of the DT fuel. A 10 mm diameter fill tube is bonded to the capsule to enable filling with the DT gas. These components must then be assembled to tolerances of approximately 5-10 microns, with comprehensive characterization and metrology. The DT ice is formed through controlled seeding, aided by beta decay of the tritium to help smooth the layer, and differential heating of the hohlraum to counteract the effects of natural convection. We present an overview of the technologies for target fabrication, assembly and metrology and advances in growth and imaging of DT ice layers. The sum of these efforts represents a quantum leap in target precision, characterization, manufacturing rate and flexibility over current state-of-the-art.

We describe a technique for cleaning a gold surface using a dry process during the fabrication of microelectromechanical system (MEMS) devices. After exposure to oxygen plasma for ashing of the organic contaminants or etching of a sacrificial-layer film, the gold surface is oxidized. On such an oxidized surface, there are different incubation periods at different places, which give rise to nonuniform thickness in electroplating as well as in electrodeposition. A surface analysis by X-ray photoelectron spectroscopy (XPS) revealed that annealing at a temperature of over 260 °C causes oxygen to desorb from the gold oxide. The application of this cleaning technique before electroplating or electrodeposition leads to uniform growth.   

We developed a method which allows us to fabricate suspended metallic structures without the need for a sacrificial layer. It consists in the selective dip-coating of a low melting point alloy on etched silicon patterns. The technique was applied to the fabrication of a passive one-shot micro-valve sensitive to the ambient temperature and the input pressure. The working principle of the valve was validated. The primary advantage of the system is its low opening pressure difference (a few to tens of kilopascal).   

We demonstrate a novel epitaxial layer-by-layer growth on upconverting NaYF(4) nanocrystals (NCs) utilizing Ostwald ripening dynamics tunable both in thickness and composition. Injection of small sacrificial NCs (SNCs) as shell precursors into larger core NCs results in the rapid dissolution of the SNCs and their deposition onto the larger core NCs to yield core-shell structured NCs. Exploiting this NC size dependent dissolution/growth, the shell thickness can be controlled either by manipulating the number of SNCs injected or by successive injection of SNCs. In either of these approaches, the NCs self-focus from an initial bimodal distribution to a unimodal distribution (? <5%) of core-shell NCs. The successive injection approach facilitates layer-by-layer epitaxial growth without the need for tedious multiple reactions for generating tunable shell thickness, and does not require any control over the injection rate of the SNCs, as is the case for shell growth by precursor injection. PMID:22734596

Solid state dewetting of ultrathin films is the most straightforward means of fabricating substrate-supported noble metal nanostructures. This assembly process is, however, quite inflexible, yielding either densely packed smaller structures or widely spaced larger structures. Here, we demonstrate the utility of introducing a sacrificial antimony layer between the substrate and noble metal overlayer. We observe an agglomeration process which is radically altered by the concurrent sublimation of antimony. In stark contrast with conventional dewetting, where the thickness of the deposited metal film determines the characteristic length scales of the assembly process, it is the thickness of the sacrificial antimony layer which dictates both the nanoparticle size and interparticle spacing. The result is a far more flexible self-assembly process where the nanoparticle size and areal density can be varied widely. Demonstrations show nanoparticle areal densities which are varied over four orders of magnitude assembled from the identical gold layer thickness, where the accompanying changes to nanostructure size see a systematic shift in the wavelength of the localized surface plasmon resonance. As a pliable self-assembly process, it offers the opportunity to tailor the properties of an ensemble of nanostructures to meet the needs of specific applications. PMID:23154213

For high-speed and low-power performance, ultrathin body (UTB) silicon on insulator (SOI) metal oxide semiconductor field-effect semiconductors (MOSFETs) with an elevated source/drain (ESD) have been investigated using selectively epitaxial growth (SEG) technology. In this work, we found that the morphology of a SEG layer on an ultrathin Si film and the crystallinity of the top Si film are strongly dependent on ion implantation damage. The morphology and surface roughness of SEG layers were investigated by field emission scanning electron microscopy (FE-SEM) and the crystallinities of the top silicon films with and without ion implantation were characterized by atomic force microscopy (AFM) and Rutherford backscattering spectroscopy (RBS), respectively. Furthermore, to suppress ion implantation damage, a SEG layer was formed before ion implantation for source drain extension (SDE) formation by the sacrificial sidewall spacer method. As results, UTB SOI-MOSFETs with a flat ESD were successfully fabricated by the proposed method.   

An improved recovery process is provided for fluent petroleum in a porous formation having spaced injection means and production well recovery means which includes a concentrated brine drive and surfactant carrier system. By injecting an aqueous drive medium having gradually decreasing brine concentration, surfactant transport and petroleum recovery efficiency are improved. Advantageously, an effective aqueous surfactant composition is formulated containing a water-soluble ether-linked sulfonate surfactant, a cosurfactant alcohol, and at least one cosurfactant or sacrificial sulfonate material in a concentrated brine carrier.

Electrocoagulation removes pollutant material from water by a combination of coagulant delivered from a sacrificial aluminium anode and hydrogen bubbles evolved at an inert cathode. Rates of clay particle flotation and settling were experimentally determined in a 7 L batch reactor over a range of currents (0.25-2.0 A) and pollutant loadings (0.1-1.7 g/L). Sedimentation and flotation are the dominant removal mechanism at low and high currents, respectively. This shift in separation mode can be explained by analysing the reactor in terms of a published dissolved air flotation model. PMID:15686019

We report on the fabrication of covalently crosslinked and amine-reactive hollow microcapsules using 'reactive' layer-by-layer assembly to deposit thin polymer films on sacrificial microparticle templates. Our approach is based on the alternating deposition of layers of a synthetic polyamine and a polymer containing reactive azlactone functionality. Multilayered films composed of branched poly(ethylene imine) (BPEI) and poly(2-vinyl-4,4-dimethylazlactone) (PVDMA) were fabricated layer-by-layer on the surfaces of calcium carbonate and glass microparticle templates. After fabrication, these films contained residual azlactone functionality that was accessible for reaction with amine-containing molecules. Dissolution of the calcium carbonate or glass cores using aqueous ethylenediamine tetraacetic acid (EDTA) or hydrofluoric acid (HF), respectively, led to the formation of hollow polymer microcapsules. These microcapsules were robust enough to encapsulate and retain a model macromolecule (FITC-dextran) and were stable for at least 22 hours in high ionic strength environments, in low and high pH solutions, and in several common organic solvents. Significant differences in the behaviors of capsules fabricated on CaCO(3) and glass cores were observed and characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Whereas capsules fabricated on CaCO(3) templates collapsed upon drying, capsules fabricated on glass templates remained rigid and spherical. Characterization using EDS suggested that this latter behavior results, at least in part, from the presence of insoluble metal fluoride salts that are trapped or precipitate within the walls of capsules after etching of the glass cores using HF. Our results demonstrate that the assembly of BPEI/PVDMA films on sacrificial templates can be used to fabricate reactive microcapsules of potential use in a wide range of fields, including catalysis, drug and gene delivery, imaging, and biomedical research. PMID:21383867

A novel windowed growth technique that allows for the exposure of a smooth silicon surface for MOS circuitry between AlGaN/GaN HEMT layers has been developed. A sacrificial oxide based dielectric stack is used to protect regions of the silicon surface before growth by ammonia-MBE. SIMS analysis shows elevated oxygen impurity incorporation in the stress-relief layer, but controllable levels in the C-doped GaN buffer. A Hall mobility of 1.37 x 10{sup 3} cm{sup 2}/Vs is measured in the AlGaN/GaN regions. AFM results show a RMS roughness of 0.12 nm on the silicon surface. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

We present two fast and generic methods for the fabrication of polymeric microfluidic systems using electron beam lithography: one that employs spatially varying electron-beam energy to expose to different depths a negative electron-beam resist, and another that employs a spatially varying electron-beam dose to differentially expose a bi-layer resist structure. Using these methods, we demonstrate the fabrication of various microfluidic unit structures such as microchannels of a range of geometries and also other more complex structures such as a synthetic gel and a chaotic mixer. These are made without using any separate bonding or sacrificial layer patterning and etching steps. The schemes are inherently simple and scalable, afford high resolution without compromising on speed and allow post CMOS fabrication of microfluidics. We expect them to prove very useful for the rapid prototyping of complete integrated micro/nanofluidic systems with sense and control electronics fabricated by upstream processes. PMID:16450043

An experimental approach for obtaining perpendicular FePt-SiOx thin films with a large height to diameter ratio FePt(L10) columnar grains is presented in this work. The microstructure for FePt-SiOx composite thin films as a function of oxide volume fraction, substrate temperature, and film thickness is studied by plan view and cross section TEM. The relations between processing, microstructure, epitaxial texture, and magnetic properties are discussed. By tuning the thickness of the magnetic layer and the volume fraction of oxide in the film at a sputtering temperature of 410 °C, a 16 nm thick perpendicular FePt film with ~8 nm diameter of FePt grains was obtained. The height to diameter ratio of the FePt grains was as large as 2. Ordering at lower temperature can be achieved by introducing a Ag sacrificial layer.

We present an advanced RMS voltage sensor based on a variable parallel-plate capacitor using the principle of electrostatic force. The device is fabricated in a micromechanical surface process with a high-aspect ratio actuator, reinforced by copper electroplating employing a sacrificial photo-resist layer. Another copper layer with a coplanar waveguide below the actuator provides separated excitation and sensing electrodes. Flip-chip technology is employed for low-loss electrical connectivity. The presented design has a plate area of up to 3??3?mm2 and an initial gap distance of only 1.5??m. We present results achieving a pull-in voltage below 1?V at frequencies from DC up to 1?GHz and sensitivities up to 1?fF/mV.

A method and micro device for repositioning or retrieving miniature devices located in inaccessible areas, such as medical devices (e.g., stents, embolic coils, etc.) located in a blood vessel. The micro repositioning or retrieving device and method uses shape memory polymer (SMP) patches formed into mating geometries (e.g., a hoop and a hook) for re-attachment of the deposited medical device to a catheter or guidewire. For example, SMP or other material hoops are formed on the medical device to be deposited in a blood vessel, and SMP hooks are formed on the micro device attached to a guidewire, whereby the hooks on the micro device attach to the hoops on the medical device, or vice versa, enabling deposition, movement, re-deposit, or retrieval of the medical device. By changing the temperature of the SMP hooks, the hooks can be attached to or released from the hoops located on the medical device. An exemplary method for forming the hooks and hoops involves depositing a sacrificial thin film on a substrate, patterning and processing the thin film to form openings therethrough, depositing or bonding SMP materials in the openings so as to be attached to the substrate, and removing the sacrificial thin film.

The materials and details used to construct sacrificial structural steel components must be evaluated for the full range of inelastic demands imposed by extreme loading events. This study characterizes the cyclic response and low-cycle fatigue life of a plate steel material designed to have a relatively low yield stress and various complete joint penetration butt-weld details considered for use in applications where inelastic behavior is expected. Large amplitude cyclic strain tests were performed on the base material and butt-welded specimens. The welded specimens utilized several different weld treatment details designed to mitigate stress concentrations, reduce tensile residual stresses, and improve weld-toe geometry. Uniaxial material models and a low-cycle fatigue model were used to c...

Ultrathin photoelectric conversion films consisting of a porphyrin–fullerene photoredox pair were fabricated by the combined use of room-temperature covalent-bonding and surface sol–gel processes. First, cysteamine was self-assembled on an indium–tin-oxide (ITO) electrode. The cysteamine-modified electrode was then immersed in C60 solution, giving immobilization of C60 via bond formation between the amino group of cysteamine and C60. Next, the C60-modified electrode was dipped in 2-ethanolamine solution to implant the hydroxy group to the immobilized C60 via the bond formation between C60 and the amino group; thus, the hydroxy group was exposed as the outermost layer. Then, Ti(OBu)4 and tetracarboxyporphyrin (TCPP) were alternately assembled on the C60 layer by the surface sol–gel process, to give an assembly of TCPP, titanium oxide species [Ti(O)], and C60 on the ITO electrode. The double layering of TCPP–Ti(O) was possible. The spectral characterization of the films was carried out. In the presence of sacrificial reagents, anodic photocurrents were generated from these modified electrodes. The incorporation of the C60 layer resulted in the substantial enhancement of the photocurrents as compared with that of the TCPP layer alone, suggesting effective electron-transfer reactions between TCPP and C60 that contribute to the photocurrent increase. The photocurrents increased by the double layering of the TCPP and Ti(O) layers.   

Barnacles are a major biofouler of man-made underwater structures. Prior to settlement, cypris larvae explore surfaces by reversible attachment effected by a 'temporary adhesive'. During this exploratory behaviour, cyprids deposit proteinaceous 'footprints' of a putatively adhesive material. In this study, footprints deposited by Balanus amphitrite cyprids were probed by atomic force microscopy (AFM) in artificial sea water (ASW) on silane-modified glass surfaces. AFM images obtained in air yielded better resolution than in ASW and revealed the fibrillar nature of the secretion, suggesting that the deposits were composed of single proteinaceous nanofibrils, or bundles of fibrils. The force curves generated in pull-off force experiments in sea water consisted of regions of gradually increasing force, separated by sharp drops in extension force manifesting a characteristic saw-tooth appearance. Following the relaxation of fibrils stretched to high strains, force-distance curves in reverse stretching experiments could be described by the entropic elasticity model of a polymer chain. When subjected to relaxation exceeding 500 ms, extended footprint proteins refolded, and again showed saw-tooth unfolding peaks in subsequent force cycles. Observed rupture and hysteresis behaviour were explained by the 'sacrificial bond' model. Longer durations of relaxation (>5 s) allowed more sacrificial bond reformation and contributed to enhanced energy dissipation (higher toughness). The persistence length for the protein chains (L(P)) was obtained. At high elongation, following repeated stretching up to increasing upper strain limits, footprint proteins detached at total stretched length of 10 microm. PMID:19570797

The performance of electrocoagulation (EC) technique for decolorization and chemical oxygen demand (COD) reduction of anaerobically pretreated poultry manure wastewater was investigated in a laboratory batch study. Two identical 15.7-L up-flow anaerobic sludge blanket (UASB) reactors were first run under various organic and hydraulic loading conditions for 216 days. Effects of operating parameters such as type of sacrificial electrode material, time of electrolysis, current density, initial pH, and electrolyte concentration were further studied to optimize conditions for the post-treatment of UASB pretreated poultry manure wastewater. Preliminary tests conducted with two types of sacrificial electrodes (Al and Fe) resulted that Al electrodes were found to be more effective for both COD and color removals than Fe electrodes. The subsequent EC tests performed with Al electrodes showed that optimal operating conditions were determined to be an initial pH of 5.0, a current density of 15mA/cm(2), and an electrolysis time of 20min. The results indicated that under the optimal conditions, about 90% of COD and 92% of residual color could be effectively removed from the UASB effluent with the further contribution of the EC technology used as a post-treatment unit. In this study, the possible acute toxicity of the EC effluent was also evaluated by a static bioassay test procedure using guppy fish (Lebistes reticulatus). Findings of this study clearly indicated that incorporation of a toxicological test into conventional physicochemical analyses provided a better evaluation of final discharge characteristics. PMID:18554794

Progress in translating nanoscience into useful nanotechnologies has been limited by an inability to drive down fabrication costs, improve throughputs, and achieve a high level of reproducibility over nanoscale structures and the properties that are controlled by size. One important nanomaterial that has incited substantial interest over the past decade is Porous Anodic Alumina (PAA). [1] The widespread use of PAA as a sacrificial template in the electrochemical synthesis of high-aspect-ratio nanomaterials has been inhibited in large part by complications related to its brittle behavior and the lack of uniformity in pore structure over large areas. The control over the shape of the growth front of electrodeposited materials in a PAA template remains as a significant challenge. This requirement is particularly relevant to "on-wire lithography" (OWL), where the inner segment of a tri-layered electrodeposited nanowire is selectively etched to achieve a nanogap of equivalent dimensionality. [2] Such a nanogap with dimensions controlled at nanometer-scale precision would have the potential to enable practical applications of molecular electronics [3] and nanoplasmonics [4]. In this work, polyethyleneimine (PEI) is used for the planarization of electrodeposited nanowire growth fronts in PAA templates. The addition of highly branched, low molecular weight PEI to an electrolytic bath provides improved uniformity in the relative distribution of nanowire growth rates from pore to pore, and allows for a more precise control over the electrochemical growth process. [5] This utility of PEI is demonstrated for the synthesis of Au-Ag-Au nanowire arrays. Upon the completion of electrodeposition, chemical etching of the Ag segment is performed, leaving behind a nanogap of a width that is determined by the thickness of the Ag segment. The achievement of electrodeposited multicomponent nanowires that yield sub-10 nm gaps in nanowires having a diameter below 100 nm is the only such demonstration to date. Finally, an electro-less process will be described for the deposition of Ag segments that allows for the creation of gaps on the order of a few atomic monolayers of Ag.

We have developed an X-band filter utilizing air-gap-type film bulk acoustic resonators (FBARs). The air-gap structure is simple and cost-effective. Results from both simulations and experiments demonstrate that a dome-shaped air gap was formed between the substrate surface and the bottom electrode and that an air-gap-type FBAR structure was possible. The air gap can be formed on the flat substrate using stress control of piezoelectric and metal films without using a thick sacrificial layer. As a result, the fabricated X-band FBAR operated successfully with a keff2 of 6.30%, a resonance Q of 246, and an antiresonance Q of 462. The fabricated filter had a center frequency of 9.07 GHz, a fractional bandwidth of 3.1% and a minimum insertion loss of 1.7 dB.   

The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at low illumination intensities, in which the etching and releasing proceeds as expected and one at higher intensities in which the etching and any releasing are completely suppressed. The “etch suppression” area is well defined by the illumination spot, a feature that can be used to create heterogeneously etched regions with a high degree of control, shown here on patterned samples. Together with the studied self-limitation effect, the technique offers a way to determine the position of rolled-up micro- and nanotubes independently from the predefined lithographic pattern.

A high Q-factor (quality-factor) spiral inductor fabricated by the CMOS (complementary metal oxide semiconductor) process and a post-process was investigated. The spiral inductor is manufactured on a silicon substrate. A post-process is used to remove the underlying silicon substrate in order to reduce the substrate loss and to enhance the Q-factor of the inductor. The post-process adopts RIE (reactive ion etching) to etch the sacrificial oxide layer, and then TMAH (tetramethylammonium hydroxide) is employed to remove the silicon substrate for obtaining the suspended spiral inductor. The advantage of this post-processing method is its compatibility with the CMOS process. The performance of the spiral inductor is measured by an Agilent 8510C network analyzer and a Cascade probe station. Experimental results show that the Q-factor and inductance of the spiral inductor are 15 at 15 GHz and 1.8 nH at 1 GHz, respectively. PMID:20531469

A passive sensor platform has been developed at the University of Texas at Austin to monitor corrosion of embedded reinforcement in concrete structures. The sensors are powered and interrogated in a wireless manner. Initial sensor designs used a sacrificial corroding steel wire to indicate the risk of corrosion within concrete. The wire was physically connected to the sensor circuitry and passed through the circuit protection layer. Consequently, it allowed contaminants to reach the circuit electric components causing corrosion and limiting the service life of the sensor. A novel sensor configuration that relies on wireless inductive coupling between a resonant circuit and the transducer element is presented. The non-contact design eliminates the breach concern and enhances the durability of the senor. Preliminary test results of the new design will be discussed in this paper.

In this paper it will be demonstrated that the conditions of the final release process in oxygen plasma strongly influence the shape of suspended gold micro-structures. Both single-clamped and double-clamped cantilever test devices have been examined. The structures have typically a thickness of 1.8mm, and are produced by patterned gold electrodeposition above a sacrificial photoresist layer which is then removed by oxygen plasma ashing. In general, deformations are strongly reduced lowering the temperature, but the release time increases abruptly. A simple model is presented to explain the experimental observation, and from it can be deduced that yield and inelastic relaxation are critical phenomena responsible for most of the deviations from the ideal planar shape of MEMS structures. To ...

In this paper, we describe the application of electrodeposition to microelectromechanical system (MEMS) devices made of gold. After the release ashing of an organic sacrificial layer by oxygen plasma exposure, the thickness of the organic dielectric film electrodeposited on gold surfaces was found to be nonuniform. A surface analysis by X-ray photoelectron spectroscopy revealed that the causes of the nonuniformity were the differences in chemical states and amounts of gold oxide that arose from oxygen plasma exposure at different places. A uniform coating was obtained by removing the gold oxide by hydrochloric acid dipping before electrodeposition on gold comb-shaped electrodes in a vibrational MEMS device. This uniform coating prevents electrical shorts and in-use sticking between the gold vibrator and electrode in the device, ensuring high durability.

A flexible polysilicon strain gauge array has been realized using a surface micromachining technique with a SiO2 sacrificial layer. The realized sensor array is mechanically flexible, which can be attached on non-planar surfaces. To realize the flexible strain gauge module, a new packaging scheme using a polyimide circuit board and an oxide based surface-micromachining was developed. The proposed packaging scheme completes the strain sensors and the circuit board on a single process, which eliminates additional assembly and alignment problems. The measured gauge factor shows that it is more sensitive than metal strain gauges. Unlike a single-crystal silicon strain gauge, the proposed polysilicon gauge has no limitations in the direction of strain.   

Coagulation imposes major impact on the removal of humic acids (HAs) and the reduction of ultrafiltration (UF) membrane fouling. In this study, titanium was used instead of iron and aluminum as a novel alternative sacrificial anode, and the removal of HAs from water by titanium-based electrocoagulation with submerged flat sheet ultrafiltration membrane was investigated. Results clearly indicate that the current intensity did have an apparent effect on the size and fractal structure of flocs. A combination of electrocoagulation with ultrafiltration can increase HAs rejection, reduce membrane fouling and decrease transmembrane pressure. Membrane permeability and the specific resistance of cake layer were controlled directly by coagulated floc structure, which was affected strongly by the app...

This works contains two parts. The first part describes some basic properties of ultra-thick negative-tone near UV photo-resist SU8 film. Nano-indentation method was used to determine the Young's modulus and hardness of SU8 and was found to be 1.8 GPa and 40 MPa respectively. High aspect ratio of 60 is obtained with a combination of wet and dry development with metallic or dielectric lithographic mask. The second part describes the process development of a simple and low cost SUR micro-fluidic system for on-chip Bio-MEMS application. The micro-fluidic system consists of several critical modules namely the chambers and channel, the micro-filter elements and the static valves. Different types of manifolds (e.g. straight, tapered and sinusoidal) were fabricated with aspect ratio less than 10. Three types of filters were designed and fabricated to extend the filtration capability from tens of microns to sub-micron dimension. The encapsulated 60mum filter was successfully tested with 67mum micro-beads. Static valves and sub-micron filters were fabricated on a sacrificial layer (e.g. Al) for subsequent removal. Removal of the sacrificial layers releases the static valve in the former case while defines the size of sub-micron filters in the latter case. Three different valves were fabricated and Ansys simulation shows that the tapered valve has the least resistance to the pressure relative to straight valve. Chamber encapsulation is essential for pressurized fluid flow from one chamber to another. A two step chamber encapsulation process with direct UV is used with the disadvantage of resist back-flowing into the channels that required additional flushing thus limits its application to only straight channel. An inverted UV exposure was proposed using an inverted UV exposure method that allowed encapsulation of any complex manifolds. Combinations of these modules enabled Bio-MEMS system to be fabricated for red and white blood separation for subsequent DNA amplifications

Light absorption across the bandgap in semiconductors is exploited in many important applications such as photovoltaics, light emitting diodes and photocatalytic conversion. Metals differ from semiconductors in that there is no energy gap separating occupied and unoccupied levels; however, it is still possible to excite electrons between bands. This is evidenced by materials with metallic properties that are also strongly coloured. An important question is whether such coloured metals could be used in light harvesting or similar applications. The high conductivity of a metal would preclude sufficient electric field being available to separate photocarriers; however, the high carrier mobility in a metal might also facilitate kinetic charge separation. Here we clearly demonstrate for the first time the use of a red metallic oxide, Sr1-xNbO3 as an effective photocatalyst. The material has been used under visible light to photocatalyse the oxidation of methylene blue and both the oxidation and reduction of water assisted by appropriate sacrificial elements.

The Evolutionary Power Reactor (EPR) is under consideration by various utilities in the United States to provide base load electrical production, and as a result the design is undergoing a certification review by the U.S. Nuclear Regulatory Commission (NRC). The severe accident design philosophy for this reactor is based upon the fact that the projected power rating results in a narrow margin for in-vessel melt retention by external cooling of the reactor vessel. As a result, the design addresses ex-vessel core melt stabilization using a mitigation strategy that includes: (1) an external core melt retention system to temporarily hold core melt released from the vessel; (2) a layer of 'sacrificial' material that is admixed with the melt while in the core melt retention system; (3) a melt plug in the lower part of the retention system that, when failed, provides a pathway for the mixture to spread to a large core spreading chamber; and finally, (4) cooling and stabilization of the spread melt by controlled top and bottom flooding. The overall concept is illustrated in Figure 1.1. The melt spreading process relies heavily on inertial flow of a low-viscosity admixed melt to a segmented spreading chamber, and assumes that the melt mass will be distributed to a uniform height in the chamber. The spreading phenomenon thus needs to be modeled properly in order to adequately assess the EPR design. The MELTSPREAD code, developed at Argonne National Laboratory, can model segmented, and both uniform and nonuniform spreading. The NRC is thus utilizing MELTSPREAD to evaluate melt spreading in the EPR design. MELTSPREAD was originally developed to support resolution of the Mark I containment shell vulnerability issue. Following closure of this issue, development of MELTSPREAD ceased in the early 1990's, at which time the melt spreading database upon which the code had been validated was rather limited. In particular, the database that was utilized for initial validation consisted of: (1) comparison to an analytical solution for the dam break problem, (2) water spreading tests in a 1/10 linear scale model of the Mark I containment by Theofanous et al., and (3) steel spreading tests by Suzuki et al. that were also conducted in a geometry similar to the Mark I. The objective of this work was to utilize the MELTSPREAD code to check the assumption of uniform melt spreading in the EPR core catcher design. As a starting point for the project, the code was validated against the worldwide melt spreading database that emerged after the code was originally written in the very early 1990's. As part of this exercise, the code was extensively modified and upgraded to incorporate findings from these various analytical and experiment programs. In terms of expanding the ability of the code to analyze various melt simulant experiments, the options to input user-specified melt and/or substrate material properties was added. The ability to perform invisicid and/or adiabatic spreading analysis was also added so that comparisons with analytical solutions and isothermal spreading tests could be carried out. In terms of refining the capability to carry out reactor material melt spreading analyses, the code was upgraded with a new melt viscosity model; the capability was added to treat situations in which solid fraction buildup between the liquidus-solidus is non-linear; and finally, the ability to treat an interfacial heat transfer resistance between the melt and substrate was incorporated. This last set of changes substantially improved the predictive capability of the code in terms of addressing reactor material melt spreading tests. Aside from improvements and upgrades, a method was developed to fit the model to the various melt spreading tests in a manner that allowed uncertainties in the model predictions to be statistically characterized. With these results, a sensitivity study was performed to investigate the assumption of uniform spreading in the EPR core catcher that addressed parametric variations in: (1) melt pour mass, (2) melt composition, (3) melt pour rate, (4) pour configuration (i.e., homogeneous vs. stratified metal-oxide phases), (5) melt temperature, (6) cavity condition (wet vs. dry), (7) spreading channel inclination angle, and finally (8) uncertainties in the melt viscosity correlation that are based on comparisons with the reactor material melt spreading database. Although differences were found in the rate of spreading and the degree to which the sacrificial concrete in the spreading room is ablated during the transients, in all cases the melt eventually (over a period of minutes) spreads to a uniform depth in the system.

We report a nanoimprint lithography method combined with photolithography on a bi-layer polymer setup to define nano-worms laterally in nano-gratings and produce uniform worm-shaped polymeric nanoparticles in aqueous solution by dissolving water soluble sacrificial layer poly(vinyl alcohol) (PVA). Process control of the thin residue layer, SU-8 curing using broadband UV source, and warm development to remove any residue are necessary to ensure success of this technique. The use of water soluble PVA as a releasing layer and elimination of an invasive plasma etching for the releasing process makes this protocol highly compatible with biomaterials. Direct release and suspension of fluorescent worm-shaped nanoparticles (length to width ratio up to 75) in aqueous solution were demonstrated. Compared to the worm-shaped nanoparticles made by self-assembly, these lithographically defined nano-worms have much better controllability and uniformity on the shape, size, and aspect ratio. The availability of these precisely defined non-spherical particles would be important to develop a comprehensive understanding of the shape effects of nanoparticles on their efficacy in nanomedicine applications. PMID:20110578

We have fabricated 3D FCC-like microstructure using multi-beam interference pattern. This polymeric structure was used as a sacrificial template. Silica was deposited into the pores by alternating exposure to water and silicon tetrachloride vapors under atmospheric pressure and at room temperature. This inorganic structure can provide a platform for the deposition of high refractive index materials such as silicon, germanium, and titania. We investigate the photonic bandgap property of this structure as a function of refractive index as well as filling ratio. Using a two-parameter level-set approach, we find that the FCC-like structure has multiple complete photonic bandgaps at 2-3 and 7-8 bands, respectively, while the bandgap width is sensitive to the morphology of coated-structure. Our calculation results suggest that the complete-filled structure possessed a wider photonic bandgap between 2 and 3 bands than the incompletely-coated core-shell structure.

Remending properties of a network polymer with reversible reactivity are described. The network structure is constructed by a Diels-Alder (DA) reaction between furyl-telechelic poly(ethylene adipate) (PEAF2) and a tris-maleimide, M3. When a film sample was cut into two pieces and the cut surfaces were kept in contact with each other at 60degreeC, rejoining of the cut pieces was observed. This mending was induced by the reversible cross-linking reaction bridging the cut surfaces. At the cut front, the "weak" DA adducts are selectively dissociated sacrificially to release the stress so as to protect the chemical structure of the prepolymer and the linker against the scission or degradation. The dissociated furan and maleimide readily reconnect by forward DA reaction to mend the material. The...

Dye-sensitized solar cells based on highly porous nanocrystalline TiO2 films have drawn considerable attention due to their high conversion efficiency and low production cost. TiO2 nanocrystalline electrodes have been investigated extensively as a key material. In this study, we discuss dye-sensitized solar cells based on macroporous TiO2 films using a highly-dispersed aqueous solution of TiO2 nanoparticles and polymeric particles. After drying this solution on the conducting glass substrate, the sacrificial polymer particles were removed selectively by thermal sintering at high temperatures over 400 degrees C or chemical treatment at the low temperature of 150 degrees C. This method provides the flexible control of TiO2 fractions or pore size or fabrication temperature. Also highly-dispersed TiO2 particles with a high crystallinity would provide a promising solution on low-temperature process for flexible DSSCs. PMID:22849098

We present a supercritical CO{sub 2} (SCCO{sub 2}) process for the preparation of nanoporous organosilicate thin films for ultra low dielectric constant materials. The porous structure was generated by SCCO{sub 2} extraction of a sacrificial poly(propylene glycol) (PPG) from a nanohybrid film, where the nanoscopic domains of PPG porogen are entrapped within the crosslinked poly(methylsilsesquioxane) (PMSSQ) matrix. As a comparison, porous structures generated by both the usual thermal decomposition (at ca. 450 C) and by a SCCO{sub 2} process for 25 wt% and 55 wt% porogen loadings were evaluated. It is found that the SCCO{sub 2} process is effective in removing the porogen phase at relatively low temperatures (< 200 C) through diffusion of the supercritical fluid into the phase-separated nanohybrids and selective extraction of the porogen phase. Pore morphologies generated from the two methods are compared from representative three-dimensional (3D) images built from small angle x-ray scattering (SAXS) data.

A series of oxygen reduction catalysts derived from pyrolyzed iron-containing compounds and a nitrogen-containing polymeric precursor, poly(ethyleneimine), (Fe-PEI) were prepared using a sacrificial support method (SSM). The synthesis includes high-temperature pyrolysis in inert atmosphere of the precursor that has been deposited onto a highly dispersed silica support, followed by etching (dissolving) the oxide support, thus resulting in a templated, self-supported, highly porous material - the non-PGM electrocatalyst. The influence of experimental parameters on the catalytic activity of the oxygen reduction reaction (ORR) in acid media was studied, such as molecular weight of PEI, temperature of the heat treatment, duration of the heat treatment, and the ratio of metal to nitrogen precurs...

A photosensitive optoelectronic device having an improved hybrid planar bulk heterojunction includes a plurality of photoconductive materials disposed between the anode and the cathode. The photoconductive materials include a first continuous layer of donor material and a second continuous layer of acceptor material. A first network of donor material or materials extends from the first continuous layer toward the second continuous layer, providing continuous pathways for conduction of holes to the first continuous layer. A second network of acceptor material or materials extends from the second continuous layer toward the first continuous layer, providing continuous pathways for conduction of electrons to the second continuous layer. The first network and the second network are interlaced with each other. At least one other photoconductive material is interspersed between the interlaced networks. This other photoconductive material or materials has an absorption spectra different from the donor and acceptor materials.

Limitations of cylindrical carbon nanotubes based on the buckminsterfullerene structure as delivery vehicles for therapeutic agents include their chemical inertness, sharp edges and toxicological concerns. As an alternative, we have developed lignin-based nanotubes synthesized in a sacrificial template of commercially available alumina membranes. Lignin is a complex phenolic plant cell wall polymer that is generated as a waste product from paper mills and biorefineries that process lignocellulosic biomass into fuels and chemicals. We covalently linked isolated lignin to the inner walls of activated alumina membranes and then added layers of dehydrogenation polymer onto this base layer via a peroxidase-catalyzed reaction. By using phenolic monomers displaying different reactivities, we were able to change the thickness of the polymer layer deposited within the pores, resulting in the synthesis of nanotubes with a wall thickness of approximately 15 nm or nanowires with a nominal diameter of 200 nm. These novel nanotubes are flexible and can be bio-functionalized easily and specifically, as shown by in vitro assays with biotin and Concanavalin A. Together with their intrinsic optical properties, which can also be varied as a function of their chemical composition, these lignin-based nanotubes are expected to enable a variety of new applications including as delivery systems that can be easily localized and imaged after uptake by living cells. PMID:22362196

SUMMiT (Sandia Ultra-planar Multi-level MEMS Technology) at the Sandia National Laboratories' MDL (Microelectronics Development Laboratory) is a standardized MEMS (Microelectromechanical Systems) technology that allows designers to fabricate concept prototypes. This technology provides four polysilicon layers plus three sacrificial oxide layers (with the third oxide layer being planarized) to enable fabrication of complex mechanical systems-on-a-chip. Quantified reproducibility of the SUMMiT process is important for process engineers as well as designers. Summary statistics for critical MEMS technology parameters such as film thickness, line width, and sheet resistance will be reported for the SUMMiT process. Additionally, data from Van der Pauw test structures will be presented. Data on film thickness, film uniformity and critical dimensions of etched line widths are collected from both process and monitor wafers during manufacturing using film thickness metrology tools and SEM tools. A standardized diagnostic module is included in each SWiT run to obtain post-processing parametric data to monitor run-to-run reproducibility such as Van der Pauw structures for measuring sheet resistance. This characterization of the SUMMiT process enables design for manufacturability in the SUMMiT technology.

Due to the toxicity of cadmium and its electroplating processes, a replacement to this widely used coating is desired. Electroplated tin-zinc alloy is a good candidate. In this thesis the electroplating of tin-zinc alloy and its corrosion behavior have been studied. Tin-zinc alloy was plated from a commercial, neutral, non-cyanide and non-toxic bath. To get an alloy deposit with a composition of 70%Sn-30%Zn, a plating current density of 5 mA/cm2 should be applied. When plating without agitation, the consumption of the H+ ions by the accompanying hydrogen evolution reaction on the cathode surface caused a local pH increase and then the formation of a hydroxide layer on the outer surface. This can be prevented by agitating the solution with nitrogen gas bubbling during plating. The alloy deposit is a fine mixture of pure zinc and tin phases. The plating current efficiency was calculated to be 71% at the plating current density of 5 mA/cm2. The tin-zinc electrodeposits have both a sacrificial property provided by zinc and a barrier property provided by tin. The open circuit potential (OCP) of the alloy coating is very close to that of zinc, so it acts as a sacrificial anode and provides a cathodic protection to the steel substrate. On the other hand, the anodic polarization current density keeps very small before the potential reaches the OCP of tin. This is because the presence of the tin on the surface forms a barrier layer which retarded the dissolution of zinc and enhanced the durability of the alloy deposit. The OCP of the tin-zinc alloys increases with corrosion duration. It is perhaps due to an IR-drop mechanism. As zinc dissolves into the solution, cavities appear on the surface. Further zinc dissolution only occurs at the bottom of the pores, while the hydrogen evolution reaction mainly occurs on the outer surface. The separation of the anodic and cathodic sites causes an IR drop. An equivalent circuit is devised and the values of the circuit elements are measured by the electrochemical impedance spectroscopy (EIS). They are in accordance with the IR drop mechanism. Chromate treatment shifts the OCP to more noble values and decreases the anodic current density. In acid solution, the chromate layer itself dissolves gradually so that the electrochemical quartz crystal microbalance (EQCM) is not suitable to estimate the zinc dissolution rate. Measurement of the polarization resistance Rp shows that, chromate treatment increases the corrosion resistance of both tin-zinc alloys and pure zinc coatings. (Abstract shortened by UMI.)

The power roadmap for EUVL high volume manufacturing (HVM) exceeds the 200W EUV in-band power at intermediate focus, thus posing more demanding requirements on HVM sources, debris suppression systems and collectors. Starting from the lessons learned in the design and fabrication of the grazing incidence collectors for the Alpha EUVL scanners, Media Lario Technologies is developing HVM optical solutions that enable designed-in lifetime improvements, such as larger source-collector distances, optimized collection efficiency through larger collected solid angles, and customized EUV reflective layers. The optical design of an HVM collector is described together with the selection of the sacrificial ruthenium reflective layer. The water cooling layout of the collector is evolved from the integrated cooling technology developed at Alpha level into an innovative cooling layout that minimizes the thermal gradients across the mirrors and allows controlling the optical performance at the far-field plane. Finally, the evolution of the collector's manufacturing technologies for HVM is discussed. XTREME technologies and Philips Extreme UV support this work by integrating the collector in the complete source collector module (SoCoMo). At system level, each component of the SoCoMo is part of a development and improvement plan leading to a comprehensive system that will fulfill the 200+ W EUV in-band power at intermediate focus.

The effective bulk diffusion length (L) in multicrystalline silicon was evaluated using the light-beam-induced-current (LBIC) technique using a geometrical configuration in which the front and back metallic contacts cover the entire front surfaces. The latter technique was performed on solar cells in cross section. We employed this particular configuration in order to evaluate the diffusion length independently of the recombination velocity at the front surface. For this purpose, we propose a new theoretical expression of the LBIC current. The diffusion length was found to be enhanced from 33 {mu}m to 65 {mu}m after gettering of undesired impurities from the bulk of the multicrystalline silicon. The gettering procedure used in this work is based on the formation of sacrificial porous silicon (PS) layers on both sides of the samples and heat treatments at different temperatures. This gettering method seems to concentrate some of the unwanted impurities close to the PS regions and to remove them by dissolving the PS layers. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

We have investigated the exciton decay in single In(Ga)As quantum dots (QD) embedded in GaAs reversed micropyramids by means of time-correlated single photon counting (TCSPC). Pyramids with square and octagonal shape are manufactured by a wet-chemical etching process utilizing an AlAs sacrificial layer. The slope angle can be tailored by the composition of the etching solution. A layer of In(Ga)As QDs is situated close to the pyramid tip (25 nm distance). This ensures an extremely low number of dots in the cavity which is important for potential applications like single photon sources. Since light emitted by the QDs is mainly radiated through the top of the reversed pyramid due to reflection at the facets, this type of cavity is useful to efficiently detect the emission of single QDs. To investigate the exciton lifetime, we have studied the emission of single QDs under pulsed laser excitation. Furthermore, we have studied the temporal auto-correlation of subsequent photons emitted by the excitonic decay of a single QD using a Hanbury-Brown and Twiss setup in order to investigate the suitability of this approach as single photon emitter.

The invention is a process for direct conversion of solid radioactive waste, particularly spent nuclear fuel and its cladding, if any, into a solidified waste glass. A sacrificial metal oxide, dissolved in a glass bath, is used to oxidize elemental metal and any carbon values present in the waste as they are fed to the bath. Two different modes of operation are possible, depending on the sacrificial metal oxide employed. In the first mode, a regenerable sacrificial oxide, e.g., PbO, is employed, while the second mode features use of disposable oxides such as ferric oxide.

A thin film structure is provided including a silicon substrate with a layer of silicon dioxide on a surface thereof, and a layer of cubic oxide material deposited upon the layer of silicon dioxide by ion-beam-assisted-deposition, said layer of cubic oxide material characterized as biaxially oriented. Preferably, the cubic oxide material is yttria-stabilized zirconia. Additional thin layers of biaxially oriented ruthenium oxide or lanthanum strontium cobalt oxide are deposited upon the layer of yttria-stabilized zirconia. An intermediate layer of cerium oxide is employed between the yttria-stabilized zirconia layer and the lanthanum strontium cobalt oxide layer. Also, a layer of barium strontium titanium oxide can be upon the layer of biaxially oriented ruthenium oxide or lanthanum strontium cobalt oxide. Also, a method of forming such thin film structures, including a low temperature deposition of a layer of a biaxially oriented cubic oxide material upon the silicon dioxide surface of a silicon dioxide/silicon substrate is provided.

Company) woven ceramic fiber with open cell foam between the layers. Multi- layer insulation ... with a spacer material, such as sheets of polyethylene terephthalate (PET) fibers to prevent contact of the adjacent metalized layer [2]. All the shell ...

The present invention provides a membrane structure, comprising in said order a first electronically conducting layer, an ionically conducting layer, and a second electronically conducting layer, characterized in that the first and second electronically conducting layers are internally short circuited. The present invention further provides a method of producing the above membrane structure, comprising the steps of : providing a ionically conducting layer; applying at least one layer of electronically conducting material on each side of said ionically conducting layer; sintering the multilayer structure; and impregnating the electronically conducting layers with a catalyst material or catalyst precursor material.

Grays Harbor and Willapa Bay are shallow embayments on the outer coast of Washington state. The US Army Corps of Engineers, Seattle District is responsible for maintenance of navigational channels in these areas, a task that requires routine dredging of deposited sediments. Dredged sediments are normally transported to designated sites for disposal. At the entrance to Grays Harbor, severe shoreline erosion has occurred. To slow erosional processes and prevent a breach at the base of the South Jetty, the USACE proposed the beneficial use of dredged materials from the bar and entrance reaches of Grays Harbor. Dredged materials deposited as sediment berms just offshore of South Beach, to the south of the jetty base, and at Half Moon Bay, to the north and east of the jetty base, could mitigate erosional processes in two ways: (1) by providing nearshore sacrificial material and a sediment supply for accretion on the shores, and (2) by tripping larger waves further offshore from the beaches. Battelle Marine Sciences Laboratory was contracted to conduct surveys at four sites in September 1993. The primary objective of this work was to determine the density of Dungeness crab at sites associated with dredging activities or dredged-materials disposal. A related objective was to assess the density of juvenile razor clams at the South Beach site, the only site in this study with potential to be an important recruitment area for juvenile razor clams.

A photosensitive device includes a plurality of organic photoconductive materials disposed in a stack between a first electrode and a second electrode, including a first continuous layer of donor host material, a second continuous layer of acceptor host material, and at least one other organic photoconductive material disposed as a plurality of discontinuous islands between the first continuous layer and the second continuous layer. Each of these other photoconductive materials has an absorption spectra different from the donor host material and the acceptor host material. Preferably, each of the discontinuous islands consists essentially of a crystallite of the respective organic photoconductive material, and more preferably, the crystallites are nanocrystals.

Photocatalytic reaction was performed by irradiation of Pt-doped TiO2 in an aqueous solution of xylose acting as a sacrificial reagent to evolve hydrogen, whose amounts reached 8.6 equivalents to the xylose used.   

We report the formation of a porous silver monolith via a novel one-pot, low-temperature reaction. This is achieved using silica hydrogel as an inorganic sacrificial template to control the resultant pore structure of the metal.   

Development of the New Effective Sacrificial Anodes on the Basis of Secondary Aluminum for Protection of Steel Constructions of Hydropower Stations and Heat Stations of the Republic of Tajikistan from Corrosion Destruction

foam that provides noise-reduction benefits and a sacrificial ... product water/ oxygen gas phase separa- tor. It can separate ... (neither wettable nor permeable by liq- uid water) covers ... reduction in wave and skin friction drag and aerothermal ...

Galvanic corrosion of copper, 1018 steel, 3003 aluminum and zinc coupled in turn to cathodes of stainless steel alloy N08367 was tested with and without natural marine biofilms on the cathode surface. Weight losses were significantly higher, and corrosion currents were up to two decades higher with a biofilm on the cathode surface for anodes of copper, steel and aluminum, but there was no difference for zinc. Results indicate that, in any case where biofilms on the cathodic member of a galvanic couple result in a systematic and significant increase in the reduction current at the mixed potential of the couple, an increase in consumption of the anodic material should be expected. Cathodic reduction currents (vs. controls with no biofilm) were increased at all potentials down to about {minus}900 mV{sub SCE}, resulting in an elevated current capacity capable of increasing the weight loss of anodic materials over a sustained period of at least two months. Biofilms, however, did not increase consumption of sacrificial anodes with potentials equal to, or more active than zinc. Potentiodynamic polarization curves taken from the corroded samples were used successfully to predict the effect of biofilms on galvanic corrosion rates for the materials tested. Weight loss values calculated by Faraday`s law using corrosion currents from the polarization curves agreed well with actual measured values for anodes of steel, aluminum and zinc, although there were some discrepancies for copper.

The present invention relates to a thin and in principle unsupported solid oxide cell, comprising at least a porous anode layer, an electrolyte layer and a porous cathode layer, wherein the anode layer and the cathode layer comprise an electrolyte material, at least one metal and a catalyst material, and wherein the overall thickness of the thin reversible cell is about 150 [mu]m or less, and to a method for producing same. The present invention also relates to a thin and in principle unsupported solid oxide cell, comprising at least a porous anode layer, an electrolyte layer and a porous cathode layer, wherein the anode layer and the cathode layer comprise an electrolyte material and a catalyst material, wherein the electrolyte material is doper zirconia, and wherein the overall thickness of the thin reversible cell is about 150 [mu]m or less, and to a method for producing same. The present invention further provides a thin separation membrane, comprising at least a porous anode layer, a membrane layer comprising a mixed conducting material and a porous cathode layer, wherein the anode layer and the cathode layer comprise the mixed conducting material and a catalyst material, and wherein the overall thickness of the thin separation membrane is about 1050 [mu]m or less.

An inert electrode connection is disclosed wherein a layer of inert electrode material is bonded to a layer of conductive material by providing at least one intermediate layer of material therebetween comprising a predetermined ratio of inert material to conductive material. In a preferred embodiment, the connection is formed by placing in a die a layer of powdered inert material, at least one layer of a mixture of powdered inert material and conductive material, and a layer of powdered conductive material. The connection is then formed by pressing the material at 15,000-20,000 psi to form a powder compact and then densifying the powder compact in an inert or reducing atmosphere at a temperature of 1200.degree.-1500.degree. C.

A number of thin liquid protection schemes involving a sacrificial thin liquid layer have been proposed to protect the first walls of inertial fusion energy reactor chambers from excessive radiation and energetic ion damage. The Prometheus study used a tangentially injected high-speed film of molten lead attached to the first wall to protect the upper endcap of the chamber reactor. Minimizing droplet formation and detachment from this film to avoid interference with beam propagation is a major design issue for such flows.Experiments were conducted on turbulent films of water injected tangentially with a rectangular nozzle into ambient air onto the underside of a horizontal flat plate. Previous efforts were focused on the effect of various design and operational parameters on the film detachment distance. This study focuses on measurement of the ''hydrodynamic source term,'' i.e., the rate of droplet formation due to primary turbulent breakup at the film surface. Droplet mass flux was measured using a simple collection technique at various standoff distances measured with respect to the plate surface and downstream distances measured from the nozzle exit. The data show that the ejected droplet mass flux increases as the standoff distance decreases and as both downstream distance and Weber number increase. Comparisons of the experimental data on the estimated ejected droplet mass flux with previously published correlations suggest that the correlations overpredict the ejected droplet mass flux by more than three orders of magnitude.

In this paper we report extremely simple 2-mask exposure fabrication process using photoresist as sacrificial layer to fabricate electromagnetically actuated torsion beam micromirror. The important feature of this reported include that the torsion beam and micromirror body are made of low stress electroplated nickel, and the torsion beam micromirror is resting on a free standing structural frame also made of electroplated copper. This device structure has resulted in a simplified fabrication process. The electroplated, low stress nickel piece having a dimension 1200×1400×4 ?m3 constitutes the mirror body and is used as reflective surface as well for magnetic interaction with magnetic field. Electromagnetic actuation in mirror is realized by control of current through a set of 500 turns copper coils on 7 cm long iron pole to which free standing mirror fixture was integrated. This structure is capable to have bi-directional actuation and a maximum deflection >24° has been obtained in static mode for the investigated electromagnet’s coil current. The electromagnetically induced deflection of our torsion mirror were modeled and shown to agree with experimental measurements.   

A simple and low-cost technology for tunable vertical-cavity surface-emitting lasers (VCSELs) with curved movable micromirror is presented. The micro-electro-mechanical system (MEMS) is integrated with the active optical component (so-called half-VCSEL) by means of surface-micromachining using a reflown photoresist droplet as sacrificial layer. The technology is demonstrated for electrically pumped, short-wavelength (850 nm) tunable VCSELs. Fabricated devices with 10 ?m oxide aperture are singlemode with sidemode suppression >35 dB, tunable over 24 nm with output power up to 0.5mW, and have a beam divergence angle actuation has a bandwidth of 400 Hz corresponding to switching times of about 10ms. The thermal crosstalk between MEMS and half-VCSEL is negligible and not degrading the device performance. With these characteristics the integrated MEMS-tunable VCSELs are basically suitable for use in reconfigurable optical interconnects and ready for test in a prototype system. Schemes for improving output power, tuning speed, and modulation bandwidth are briefly discussed.

Coupling of nano-photonic devices to color centers in diamond offers exceptional opportunities to enhance our understanding of light-matter interactions. The formation of thin single crystal diamond membranes containing such centers, is an important prerequisite for the fabrication of diamond based devices. However, there are challenges in forming such membranes in ways that do not compromise the quality of the cavities or the optical properties of the emitters. Here we report the formation of optically active diamond membranes and the subsequent fabrication of optical cavities. In our approach, 1.7 ?m thick diamond membranes were generated by forming a sacrificial layer using ion implantation, followed by thermal annealing. These membranes then served as templates for the epitaxial overgrowth of ˜ 300 nm of diamond using CVD. Remarkably, the regrown films reveal the presence of optically active defects which were not present in the template, such as silicon-vacancy (SiV) or nitrogen vacancy centers. Microdisk cavities were then formed from the regrown single crystal diamond membranes. Whispering gallery modes (WGMs) with quality factors of ˜ 3000 were measured from the diamond cavities. Spectral overlap of WGMs with the zero phonon line of SiV centers was observed and lifetime reduction of the coupled emitter -- cavity system was measured. The demonstration of coupling between diamond emitters and a single crystal diamond cavity is a crucial step towards diamond integrated nano-photonic networks.

Surface-micromachined silicon inertial sensors are limited to relatively high-G applications in part because of the fundamental limitations on proof mass imposed by the manufacturing technology. At the same time, traditional micromolding technologies such as LIGA do not lend themselves to integration with electronics, a capability which is equally necessary for high-performance inertial sensors. The silicon micromolding processes described in this report promise to offer both larger proof masses and integrability with on-chip electronics. In Sandia`s silicon micromolding process, the proof mass is formed using a mold which is first recessed into the substrate using a deep silicon trench etch, then lined with a sacrificial or etch-stop layer, and filled with mechanical polysilicon. Since the mold is recessed into the substrate, the whole micromechanical structure can be formed, planarized, and integrated with standard silicon microelectronic circuits before the release etch. In addition, unlike surface-micromachined parts, the thickness of the molded parts is limited by the depth of the trench etch (typically 10--50 {micro}m) rather than the thickness of deposited polysilicon (typically 2 {micro}m). The fact that the high-aspect-ratio section of the device is embedded in the substrate enables the monolithic integration of high-aspect-ratio parts with surface-micromachined mechanical parts, and, in the future, also electronics. The authors anticipate that such an integrated mold/surface micromachining/electronics process will offer versatile high-aspect-ratio micromachined structures that can be batch-fabricated and monolithically integrated into complex microelectromechanical systems including high-performance inertial sensing systems.

A ceramic superconductor comprising a metal oxide substrate, a ceramic high temperature superconductive material, and a intermediate layer of a material having a cubic crystal structure, said layer situated between the substrate and the superconductive material is provided, and a structure for supporting a ceramic superconducting material is provided, said structure comprising a metal oxide substrate, and a layer situated over the surface of the substrate to substantially inhibit interdiffusion between the substrate and a ceramic superconducting material deposited upon said structure.

Latest developments in micro-electro-mechanical systems (MEMS) have paved the way to follow the more than Moore approach. Several key components, such as silicon pressure sensors have been developed using MEMS processing techniques. Recently, MEMS technologies have been combined with standard CMOS processes and MEMS devices such as microviscosimeters and RF-MEMS switches were successfully demonstrated. The most challenging part of this MEMS process is the last long wet etch step, which remove the sacrificial layer to make the actuator moveable. Such long etch step is strongly influenced by the previous lithography steps. Especially the type of the photoresist has a strong influence on the performance of the final MEMS device. Here, we report a novel MEMS fabrication process, applied to the back-end-off-line (BEOL) of a 0.25?m SiGe BiCMOS technology. The full MEMS process flow is explained and the last lithography step is detailed. First, we show the influence of different substrate surface preconditions which defines the adhesion between the photoresist and the substrate. The final 6?m thick photoresist layer is required for the critical MEMS actuator release procedure due to the long wet etch process. In this wet etch process, a buffered hydrofluoric acid etchant penetrates the resist layer due to the long etch time (>80 min). Such penetration becomes more critical in the case of low adhesion between the photoresist and the wafer surface. Improving the latter can be achieved by using different primers or dehydration bakes. Furthermore, a new approach of an alternative standard lithography process is investigated. For both studies, additional SEM cross sections and contact angle measurements is presented.

The lamination process determines the quality of low temperature co-fired ceramics (LTCC) based spatial structures. This paper compares two methods of the microchannel fabrication process in zero-shrinkage LTCC substrates. The first one is based on a two-step lamination process and uses various sacrificial volume materials (SVM). The second one is based on the cold chemical lamination (CCL) process. On the one hand, the SVM gives the possibility of decreasing the deformation of the three-dimensional (3D) structures during the lamination process. The channel volume is filled with a special fugitive material. It protects the spatial structure from deformation during lamination, and evaporates completely during the co-firing process. The bonding quality and strength depend strongly on the fugitive phase type. On the other hand, the CCL is a solvent-based method. It is another alternative for bonding of green ceramic tapes. A special liquid agent is screen printed on the green tape, which melts the tape surface. Then the tapes are stacked and compressed at room temperature by a printing roll. The influence of each method on the microchannel geometry is analyzed in this paper. The resulting structures' bonding quality and mechanical properties are examined by a scanning electron microscope (SEM).

Low Temperature Cofired Ceramic (LTCC) has proven to be an enabling medium for microsystem technologies, because of its desirable electrical, physical, and chemical properties coupled with its capability for rapid prototyping and scalable manufacturing of components. LTCC is viewed as an extension of hybrid microcircuits, and in that function it enables development, testing, and deployment of silicon microsystems. However, its versatility has allowed it to succeed as a microsystem medium in its own right, with applications in non-microelectronic meso-scale devices and in a range of sensor devices. Applications include silicon microfluidic ''chip-and-wire'' systems and fluid grid array (FGA)/microfluidic multichip modules using embedded channels in LTCC, and cofired electro-mechanical systems with moving parts. Both the microfluidic and mechanical system applications are enabled by sacrificial volume materials (SVM), which serve to create and maintain cavities and separation gaps during the lamination and cofiring process. SVMs consisting of thermally fugitive or partially inert materials are easily incorporated. Recognizing the premium on devices that are cofired rather than assembled, we report on functional-as-released and functional-as-fired moving parts. Additional applications for cofired transparent windows, some as small as an optical fiber, are also described. The applications described help pave the way for widespread application of LTCC to biomedical, control, analysis, characterization, and radio frequency (RF) functions for macro-meso-microsystems.

Recent work has shown that an important drill bit wear mechanism in aqueous environments is electrochemical in nature. The synergistic effects of corrosion and abrasion are responsible for a large percentage of bit wear in laboratory studies. It has been shown that measured wear rates can be reduced by factors of two to five with the application of a voltage potential which opposes and exceeds the galvanic potential generated by the corrosion cells existing downhole. The present study investigates the potential for applying this technique in the downhole environment. The results demonstrate that a downhole generator sub powered by drilling fluid is a possible electrical power source. Graphite is chosen as the optimal nonsacrificial anode material for this application. Steel is also shown to be a possible anode material, but the anode would be sacrificial in this case, requiring periodic replacement. The electrical power required to achieve the desired effect for 4-1/2 inch drill bit is determined to be on the order of one milliwatt. Additionally, up to 250 feet of 4 inch drill pipe could be protected from corrosion with power levels on the order of 150 milliwatts. These relatively low power levels suggest that dry cell batteries could alternatively be employed as the power source; however, the temperature limitations of commercially available batteries would have to be overcome for geothermal applications.

One-dimensional nanostructures such as silicon nanowires (SiNW) are attractive candidates for low power density electronic and optoelectronic devices including sensors. A new simple method for SiNW bulk synthesis[1, 2] is demonstrated in this work, which is inexpensive and uses low toxicity materials, thereby offering a safe, energy efficient and green approach. The method uses low flammability liquid phenylsilanes, offering a safer avenue for SiNW growth compared with using silane gas. A novel, duo-chamber glass vessel is used to create a low-pressure environment where SiNWs are grown through vapor-liquid-solid mechanism using gold nanoparticles as a catalyst. The catalyst decomposes silicon precursor vapors of diphenylsilane and triphenylsilane and precipitates single crystal SiNWs, which appear to grow parallel to the substrate surface. This opens up possibilities for synthesizing nano-junctions amongst wires which is important for the grid architecture of nanoelectronics proposed by Likharev[3]. Even bulk synthesis of SiNW is feasible using sacrificial substrates such as CaCO(3) that can be dissolved post-synthesis. Furthermore, by dissolving appropriate dopants in liquid diphenylsilane, a controlled doping of the nanowires is realized without the use of toxic gases and expensive mass flow controllers. Upon boron doping, we observe a characteristic red shift in photoluminescence spectra. In summary, an inexpensive and versatile method for SiNW is presented that makes these exotic materials available to any lab at low cost. PMID:20711489

An optoelectronic device and a method for fabricating the optoelectronic device includes a first electrode disposed on a substrate, an exposed surface of the first electrode having a root mean square roughness of at least 30 nm and a height variation of at least 200 nm, the first electrode being transparent. A conformal layer of a first organic semiconductor material is deposited onto the first electrode by organic vapor phase deposition, the first organic semiconductor material being a small molecule material. A layer of a second organic semiconductor material is deposited over the conformal layer. At least some of the layer of the second organic semiconductor material directly contacts the conformal layer. A second electrode is deposited over the layer of the second organic semiconductor material. The first organic semiconductor material is of a donor-type or an acceptor-type relative to the second organic semiconductor material, which is of the other material type.

Planar ceramic membrane assembly comprising a dense layer of mixed-conducting multi-component metal oxide material, wherein the dense layer has a first side and a second side, a porous layer of mixed-conducting multi-component metal oxide material in contact with the first side of the dense layer, and a ceramic channeled support layer in contact with the second side of the dense layer. The planar ceramic membrane assembly can be used in a ceramic wafer assembly comprising a planar ceramic channeled support layer having a first side and a second side; a first dense layer of mixed-conducting multi-component metal oxide material having an inner side and an outer side, wherein the inner side is in contact with the first side of the ceramic channeled support layer; a first outer support layer comprising porous mixed-conducting multi-component metal oxide material and having an inner side and an outer side, wherein the inner side is in contact with the outer side of the first dense layer; a second dense layer of mixed-conducting multi-component metal oxide material having an inner side and an outer side, wherein the inner side is in contact with the second side of the ceramic channeled layer; and a second outer support layer comprising porous mixed-conducting multi-component metal oxide material and having an inner side and an outer side, wherein the inner side is in contact with the outer side of the second dense layer.

Photovoltaic (PV) cells with a three dimensional (3D) morphology are an exciting new research thrust with promise to create cheaper, more efficient solar cells. This work introduces a new type of 3D PV device based on carbon nanotube (CNT) arrays. These arrays are paired with the thin film heterojunction, CdTe/CdS, to form a complete 3D carbon nanotube PV device (3DCNTPV). Marriage of a complicated 3D structure with production methods traditionally used for planar CdTe solar cell is challenging. This work examines the problems associated with processing these types of cells and systematically alters production methods of the semiconductor layers and electrodes to increase the short circuit current (Isc), eliminate parasitic shunts, and increase the open circuit voltage (Voc). The main benefit of 3D solar cell is the ability to utilize multiple photon interactions with the solar cell surface. The three dimensionality allows photons to interact multiple times with the photoactive material, which increases the absorption and the overall power output over what is possible with a two dimensional (2D) morphology. To quantify the increased power output arising from these multiple photon interactions, a new absorption efficiency term, eta3D, is introduced. The theoretical basis behind this new term and how it relates to the absorption efficiency of a planar cell, eta 2D, is derived. A unique model for the average number of multiple photon impingements, Gamma, is proposed based on three categories of 3D morphology: an infinite trench, an enclosed box, and an array of towers. The derivation of eta3D and Gamma for these 3D PV devices gives a complete picture of the enhanced power output over 2D cells based on CNT array height, pitch, radius, and shape. This theory is validated by monte carlo simulations and experiment. This new type of 3D PV devices has been shown to work experimentally. The first 3DCNTPV cells created posses Isc values of 0.085 to 17.872mA/cm2 and Voc values in the range of 2 to 122mV. These figures of merit are low for CdTe cells, so planar cells without CNTs and planar cells with unpatterned CNTs were developed. The planar cells had figures of merit about the same as the 3DCNTPV cells, indicating that the low efficiency of the 3DCNTPV cell is due to processing and not inherent to the 3D structure. CNTs were successfully grown directly on an Ag underlayer, but the growth reproducibility and the CNT height was not sufficient for use in 3DCNTPV devices. Therefore, CNTs were grown on a SiO2 passivated Si wafer and then metallized. This eliminated the CNTs as the back contact and used them only as a structure to provide the 3D morphology. These cells exhibited low shunt resistances on the order of 300O, causing a straight line IV curve. This shunting was found to be caused by the ion assisted deposition of ITO. This plasma process etched away semiconducting layers and caused pinholes in the CdTe/CdS film. Many different strategies were utilized to try and eliminate this shunt and induce curvature in the IV curve, including adding sacrificial metal layers before the ITO deposition, using electron beam evaporated ITO, and using RF sputtered ITO. The addition of metal layers before ITO deposition did not result in cells which could reliably demonstrate both photocurrent and IV curvature. Electron beam deposition of ITO resulted in cells with excellent IV curvature, but the ITO deposited in this manner was too resistive and absorptive to create well functioning cells. The output power of the cells at varying incident angles of light was measured. The cells show an increase in the normalized power output compared to similar planar cells when the solar ux is at off-normal angles. The power output vs. incident angle curve takes an inverted C-type curve as predicted by the theory developed here. The complete theory of 3DCNTPV presented in this work describes the power output vs. incident angle of a 3DCNTPV cell based only on cell morphology. The experimental power output vs. zenith angle was compared to the theoretically calculated power output with very good agreement between the two. (Abstract shortened by UMI.)

A plurality of layers of a first semiconductor material and a plurality of dots-in-a-fence barriers disposed in a stack between a first electrode and a second electrode. Each dots-in-a-fence barrier consists essentially of a plurality of quantum dots of a second semiconductor material embedded between and in direct contact with two layers of a third semiconductor material. Wave functions of the quantum dots overlap as at least one intermediate band. The layers of the third semiconductor material are arranged as tunneling barriers to require a first electron and/or a first hole in a layer of the first material to perform quantum mechanical tunneling to reach the second material within a respective quantum dot, and to require a second electron and/or a second hole in a layer of the first semiconductor material to perform quantum mechanical tunneling to reach another layer of the first semiconductor material.

The microstructural evolution of ZrB"2-20vol% MoSi"2 composites during heat treatment with and without pressure at 2000^oC for 1h in argon was investigated. Results showed the materials exhibited a multiphase layered structure after heat treatment without pressure. From surface to center, the layered structure consisted of (1) a Mo layer, (2) a Si layer, (3) a ZrB"2-MoSi"2 layer and (4) a partially MoSi"2-depleted ZrB"2 layer. The formation mechanism of layered structure was analyzed. After heat treatment with pressure, the materials with high toughness mainly contained ZrB"2 phase.

ABSTRACT. The strength characteristics of quasi-homogeneous, nonisotropic materials are derived .... of material properties through the selection of proper constituent materials and their ..... in “dog-bone” fashion. .... For an orthotropic layer, ...

The present invention provides a membrane, comprising in this order a first catalyst layer, an electronically and ionically conducting layer having a nanosized microstructure, and a second catalyst layer, characterized in that the electronically and ionically conducting layer is formed from an electrolyte material, a grain growth inhibitor and/or grain boundary modifier, and a method for producing same.

A template article including a base substrate including: (i) a base material selected from the group consisting of polycrystalline substrates and amorphous substrates, and (ii) at least one layer of a differing material upon the surface of the base material; and, a buffer material layer upon the base substrate, the buffer material layer characterized by: (a) low chemical reactivity with the base substrate, (b) stability at temperatures up to at least about 800.degree. C. under low vacuum conditions, and (c) a lattice crystal structure adapted for subsequent deposition of a semiconductor material; is provided, together with a semiconductor article including a base substrate including: (i) a base material selected from the group consisting of polycrystalline substrates and amorphous substrates, and (ii) at least one layer of a differing material upon the surface of the base material; and, a buffer material layer upon the base substrate, the buffer material layer characterized by: (a) low chemical reactivity with the base substrate, (b) stability at temperatures up to at least about 800.degree. C. under low vacuum conditions, and (c) a lattice crystal structure adapted for subsequent deposition of a semiconductor material, and, a top-layer of semiconductor material upon the buffer material layer.

For many years, users have utilized modified forms of the NACE TM 0190-90 2 week constant impressed current test to assure the quality of sacrificial anode materials. With refinements which have been added periodically since the test was first discussed, the test has served well to ensure that the anodes do cathodically protect offshore structures and pipelines against corrosion. An alternative 4 day test recommended by Det Norske Veritas Industri Norge AS offers some advantages and is strongly preferred by European vendors, thus a comparison of the two test methods has been conducted. Results show that for a set of sixteen Al/Zn/Si/In anodes, with mixed performance characteristics, the two test methods are not directly comparable. However, with adjustment of the accept/reject criteria, the results become more comparable. Substitution of the Four day test for the two week test may produce a modestly increased risk of substandard anode performance. The cathodic protection (CP) design engineer may evaluate this risk and decide if it is acceptable, or alternatively may adjust the CP design conservatism slightly to compensate. Lastly, conditions in the Four day test are even further from actual service than in the two week test, thus results are probably less useful for predicting in-service performance.

Low-temperature co-fired ceramic (LTCC) enables development and testing of critical elements on microsystem boards as well as nonmicroelectronic meso-scale applications. We describe silicon-based microelectromechanical systems packaging and LTCC meso-scale applications. Microfluidic interposers permit rapid testing of varied silicon designs. The application of LTCC to micro-high-performance liquid chromatography (?-HPLC) demonstrates performance advantages at very high pressures. At intermediate pressures, a ceramic thermal cell lyser has lysed bacteria spores without damaging the proteins. The stability and sensitivity of LTCC/chemiresistor smart channels are comparable to the performance of silicon-based chemiresistors. A variant of the use of sacrificial volume materials has created channels, suspended thick films, cavities, and techniques for pressure and flow sensing. We report on inductors, diaphragms, cantilevers, antennae, switch structures, and thermal sensors suspended in air. The development of 'functional-as-released' moving parts has resulted in wheels, impellers, tethered plates, and related new LTCC mechanical roles for actuation and sensing. High-temperature metal-to-LTCC joining has been developed with metal thin films for the strong, hermetic interfaces necessary for pins, leads, and tubes.

Carbon-doped tungsten trioxide (WO{sub 3}) films were produced using a spray-pyrolysis methodology, with glucose used as the carbon dopant source. The films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis, scanning electron microscopy, and solid-state nuclear magnetic resonance. The photoelectrochemical activity was evaluated under near UV-visible light and visible light only irradiation conditions. The presence of carbonate-type species in the C-doped sample was confirmed by XPS and SSNMR. The C-doped WO{sub 3} electrodes exhibited photocurrent densities up to 1.6 mA/cm{sup 2} in 1 M HCl electrolyte and as high as 2.6 mA/cm{sup 2} with the addition of methanol as a sacrificial agent. A high contribution ({proportional_to}50%) of the photocurrent density was observed from visible light. C-doped WO{sub 3} produced approximately 50% enhanced photocurrent densities compared with the undoped WO{sub 3} electrode synthesized using the same procedures. The photoelectrochemical performance was optimized with respect to several synthetic parameters, including dopant concentration, calcination temperature and film thickness. These results indicate the potential for further development of WO{sub 3} photocatalysts by simple wet chemical methods, and provide useful information towards understanding the structure and enhanced photoelectrochemical properties of these materials. (author)

Amino-functional macroporous monoliths from polymerized high internal phase emulsion (polyHIPE) were surface modified with initiators for atom transfer radical polymerization (ATRP). The ATRP initiator groups on the polyHIPE surface were successfully used to initiate activator regeneration by electron transfer (ARGET) ATRP of (meth)acrylic monomers, such as methyl methacrylate (MMA) or tert-butyl acrylate (tBA) resulting in a dense coating of polymers on the polyHIPE surface. Addition of sacrificial initiator permitted control of the amount of polymer grafted onto the monolith surface. Subsequent removal of the tert-butyl protecting groups yielded highly functional polyHIPE-g-poly(acrylic acid). The versatility to use the high density of carboxylic acid groups for secondary reactions was demonstrated by the successful conjugation of enhanced green fluorescent protein (eGFP) and coral derived red fluorescent protein (DsRed) using EDC/sulfo-NHS chemistry, on the polymer 3D-scaffold surface. The materials and methodologies presented here are simple and robust, thus, opening new possibilities for the bioconjugation of highly porous polyHIPE for bioseparation applications. PMID:23077969

The use of a MgO delay bed as a sacrificial material to accommodate core debris within the reactor cavity following a major core disruptive accident involving reactor vessel and guard vessel failure has been considered as one of the likely core retention concepts in LMFBR safety studies. The primary objective of this concept is to prevent direct contact of sodium with concrete so as to minimize the sodium-concrete interactions which result in gas evolution from the concrete structure and the chemical energy release. Another important objective is to provide an effective means of decay heat removal utilizing the large thermal mass of the MgO bed. Characterization has been made of the nature of phenomena involved in the interactions and the potential sequence of their occurrence. A flow diagram for accident progression has been constructed to describe the likely events that may take place in the cavity. The transport rate and mechanism as well as the time scale of each event have been determined by a scoping analysis.

Poly(methyl methacrylate) in the brush form is grown from the surface of magnetite nanoparticles by ambient temperature atom transfer radical polymerization (ATATRP) using a phosphonic acid based initiator. The surface initiator was prepared by the reaction of ethylene glycol with 2-bromoisobutyrl bromide, followed by the reaction with phosphorus oxychloride and hydrolysis. This initiator is anchored to magnetite nanoparticles via physisorption. The ATATRP of methyl methacrylate was carried out in the presence of CuBr/PMDETA complex, without a sacrificial initiator, and the grafting density is found to be as high as 0.90 molecules/nm2. The organic inorganic hybrid material thus prepared shows exceptional stability in organic solvents unlike unfunctionalized magnetite nanoparticles which tend to flocculate. The polymer brushes of various number average molecular weights were prepared and the molecular weight was determined using size exclusion chromatography, after degrafting the polymer from the magnetite core. Thermogravimetric analysis, X-ray photoelectron spectra and diffused reflection FT-IR were used to confirm the grafting reaction.

An optoelectronic device and a method of fabricating a photosensitive optoelectronic device includes depositing a first organic semiconductor material on a first electrode to form a continuous first layer having protrusions, a side of the first layer opposite the first electrode having a surface area at least three times greater than an underlying lateral cross-sectional area; depositing a second organic semiconductor material directly on the first layer to form a discontinuous second layer, portions of the first layer remaining exposed; depositing a third organic semiconductor material directly on the second layer to form a discontinuous third layer, portions of at least the second layer remaining exposed; depositing a fourth organic semiconductor material on the third layer to form a continuous fourth layer, filling any exposed gaps and recesses in the first, second, and third layers; and depositing a second electrode on the fourth layer, wherein at least one of the first electrode and the second electrode is transparent, and the first and third organic semiconductor materials are both of a donor-type or an acceptor-type relative to second and fourth organic semiconductor materials, which are of the other material type.

NASTRAN Model with Adhesive Layer . ... Sheer Stress in Adhesive Layer . ..... Many toughened residfiber systems introduced by many suppliers of .... 1808I/ IM6 carbon-epoxy composite material system at room temperature, dry, under an in- ...

A method and apparatus using cold gas jets for producing a substantially uniform layer of cryogenic materials on the inner surface of hollow spherical members having one or more layers, such as inertially imploded targets. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on an inner surface of the spherical member. Basically the method involves directing cold gas jets onto a spherical member having one or more layers or shells and containing the cryogenic material, such as a deuterium-tritium (DT) mixture, to freeze the contained material, momentarily heating the spherical member so as to vaporize the contained material, and quickly refreezing the thus vaporized material forming a uniform layer of cryogenic material on an inner surface of the spherical member.

An armor material is sometimes peeled off by the breakage of a joining layer due to thermal stresses caused upon high thermal load exerted on the armor material or electromagnetic forces generated in a vacuum vessel. In a method of manufacturing a plasma facing material by bonding the armor material comprising carbon material and a cooling member comprising copper, carbon fibers and a brazing material are inserted between the armor material and the cooling member and heated to bond the armor material and the cooling member. As a result, since the carbon fibers are contained in the joining layer between the armor material and the cooling material, the joining layer (a mixed layer of carbon fiber/brazing material) has a heat expansion intermediate between that of the carbon material and copper, heat stresses are reduced, and since the strength of the joining layer itself is improved, the breakage of the joining layer is less caused compared with a joining layer in a conventional case. This can improve the reliability of the joined layer remarkably. (N.H.)

The fluence dependence of D ion reflection and sputtering from C-layered W material, W-layered C material and WxC1-x mixed material, has been demonstrated using the dynamic Monte Carlo program, EDDY. The fluence-dependent depth profile distributions explain such fluence dependence. For the layered materials, the fluence variations of reflection and sputtering are dependent on layer thickness. In particular, for the C layer thickness parallel to the mean ion range for the impact to pure C, the sputtering of the C layer is enhanced with increasing fluence by C emission due to the reflective scattering collisions of D with W near the surface. This is essentially due to the large target mass difference between W and C, which also brings about the fluence variations for the mixed material. The C sputtering is suppressed due to the dynamic behavior of C in the mixed material, whereas the reflection and W sputtering are enhanced.   

An integrated approach, including a continuum theory of sintering and mesostructure evolution analysis, is used for the solution of the problem of bi-layered structure sintering. Two types of bi-layered structures are considered: layers of the same material different by initial porosity, and layers of two different materials. The effective sintering stress and the normalized bulk modulus for the bi-layer powder sintering are derived based on mesoscale simulations. The combined effect of the layers' porosity and differences in sintering rate on shrinkage and warpage is studied for both sintering on a rigid substrate and free sintering.

ABS>A reactor pressure vessel is designed with a wall section formed of a plurality of relatively thin metal layers with a neutron-absorbing layer disposed between two layers. The neutron-absorbing layer should be made out of a material with a thermal neutron cross section of >200 barns and a high thermal conductivity, and it should be adjacent a cooling surface or a cooling passage. Two embodiments of a multi-layer wall sectton are described. (D.J.C.)

The thickness of transition layer of crystal polymer is generally calculated by one dimensional electron density correlation function. If the transition layer of crystal polymer is diffusive, corrected Porod's law is an effective method to deal with diffuse transition layer of pseudo two-phase material. The method of Porod's law is used to compute the thickness of transition layer of crystal polymer and compared with the result of correlation function method. The conclusion is that two methods obtain identical thickness of transition layer

A sacrificial plastic mold having an electroplatable backing is provided. One embodiment consists of the infusion of a softened or molten thermoplastic through a porous metal substrate (sheet, screen, mesh or foam) and into the features of a micro-scale molding tool contacting the porous metal substrate. Upon demolding, the porous metal substrate will be embedded within the thermoplastic and will project a plastic structure with features determined by the mold tool. This plastic structure, in turn, provides a sacrificial plastic mold mechanically bonded to the porous metal substrate which provides a conducting support suitable for electroplating either contiguous or non-contiguous metal replicates. After electroplating and lapping, the sacrificial plastic can be dissolved to leave the desired metal structure bonded to the porous metal substrate. Optionally, the electroplated structures may be debonded from the porous substrate by selective dissolution of the porous substrate or a coating thereon.

Abstract. Human altruistic behavior has received a great deal of scientific attention over the past forty years. Altruistic-like behaviors found among insects and animals have illumined certain human behaviors, and the revival of interest in group selection has focused attention on how sacrificial altruism, although not adaptive for individuals, can be adaptive for groups. Curiously, at the same time that sociobiology has placed greater emphasis on the value of sacrificial altruism, Protestant ethics in America has moved away from it. While Roman Catholic ethics has a longstanding tradition emphasizing an ordering of love, placing love of self second only to love for God, Protestant ethics in America has adopted a similar stance only recently, replacing a strong sacrificial ethic with one ...

The present invention includes a catalyst that has at least four layers, (1) porous support, (2) buffer layer, (3) interfacial layer, and optionally (4) catalyst layer. The buffer layer provides a transition of thermal expansion coefficient from the porous support to the interfacial layer thereby reducing thermal expansion stress as the catalyst is heated to high operating temperatures. The method of the present invention for making the at least three layer catalyst has the steps of (1) selecting a porous support, (2) solution depositing an interfacial layer thereon, and optionally (3) depositing a catalyst material onto the interfacial layer; wherein the improvement comprises (4) depositing a buffer layer between the porous support and the interfacial layer.

Compared to surface grinding, wire-electrodischarge machining (WEDM) is competitive because WEDM allows the machining of any type of conductive material, regardless of its hardness. Nevertheless, WEDM is not preferred for final machining due to the existence of the process-induced damaged layers. In this study, the damaged layers formed in hardened AISI 52100 steel by surface grinding and WEDM are researched and compared. It is found that the damaged layers for both grinding and WEDM are composed of the white layer and dark layer, and the white layer possesses a highly refined grain structure compared to the bulk material. The retained austenite content of the ground white layer is lower than that of the unmachined material, while WEDM white layer has much high retained austenite volume fr...

One or more thin film solar cells in which the intrinsic layer of substantially amorphous semiconductor alloy material thereof includes at least a first band gap portion and a narrower band gap portion. The band gap of the intrinsic layer is spatially graded through a portion of the bulk thickness, said graded portion including a region removed from the intrinsic layer-dopant layer interfaces. The band gap of the intrinsic layer is always less than the band gap of the doped layers. The gradation of the intrinsic layer is effected such that the open circuit voltage and/or the fill factor of the one or plural solar cell structure is enhanced.

A cold isopressing method in which two or more layers of material are formed within an isopressing mold. One of the layers consists of a tape-cast film. The layers are isopressed within the isopressing mold, thereby to laminate the layers and to compact the tape-cast film. The isopressing mold can be of cylindrical configuration with the layers being coaxial cylindrical layers. The materials used in forming the layers can contain green ceramic materials and the resultant structure can be fired and sintered as necessary and in accordance with known methods to produce a finished composite, ceramic structure. Further, such green ceramic materials can be of the type that are capable of conducting hydrogen or oxygen ions at high temperature with the object of utilizing the finished composite ceramic structure as a ceramic membrane element.

ABSTRACT: Large arrays of multifunctional rolled-up semiconductors can be mass produced with precisely controlled size and composition, making them of great technological interest for micro- and nano-scale device fabrication. The microtube behavior at different temperatures is a key factor towards further engineering their functionality, as well as for characterizing strain, defects, and temperature-dependent properties of the structures. For this purpose, we probe optical phonons of GaAs/InGaAs rolled-up microtubes using Raman spectroscopy on defect-rich (faulty) and defect-free microtubes. The microtubes are fabricated by selectively etching an AlAs sacrificial layer in order to release the strained InGaAs/GaAs bilayer, all grown by molecular beam epitaxy. Pristine microtubes show homogeneity of the GaAs and InGaAs peak positions and intensities along the tube, which indicates a defect-free rolling up process, while for a cone-like microtube, a downward shift of the GaAs LO phonon peak along the cone is observed. Formation of other type of defects, including partially unfolded microtubes, can also be related to a high Raman intensity of the TO phonon in GaAs. We argue that the appearance of the TO phonon mode is a consequence of further relaxation of the selection rules due to the defects on the tubes, which makes this phonon useful for failure detection/prediction in such rolled up systems. In order to systematically characterize the temperature stability of the rolled up microtubes, Raman spectra were acquired as a function of sample temperature up to 300[degree sign]C. The reversibility of the changes in the Raman spectra of the tubes within this temperature range is demonstrated. PMID:23101911

A novel field emitter device for cold cathode field emission applications, comprising a multi-layer resistive carbon film. The multi-layered film of the present invention is comprised of at least two layers of a resistive carbon material, preferably amorphous-tetrahedrally coordinated carbon, such that the resistivities of adjacent layers differ. For electron emission from the surface, the preferred structure comprises a top layer having a lower resistivity than the bottom layer. For edge emitting structures, the preferred structure of the film comprises a plurality of carbon layers, wherein adjacent layers have different resistivities. Through selection of deposition conditions, including the energy of the depositing carbon species, the presence or absence of certain elements such as H, N, inert gases or boron, carbon layers having desired resistivities can be produced. Field emitters made according the present invention display improved electron emission characteristics in comparison to conventional field emitter materials.

The invention comprises new materials useful in a wide variety of terrestrial and space applications. In one aspect, the invention comprises a flexible cloth-like material comprising a layer of flexible woven ceramic fabric bonded with a layer of metallic foil. In another aspect, the invention includes a flexible fluid impermeable barrier comprising a flexible woven ceramic fabric layer having metal wire woven therein. A metallic foil layer is incontinuously welded to the woven metal wire. In yet another aspect, the invention includes a material comprising a layer of flexible woven ceramic fabric bonded with a layer of an organic polymer. In still another aspect, the invention includes a rigid fabric structure comprising a flexible woven ceramic fabric and a resinous support material which has been hardened as the direct result of exposure to ultraviolet light. Inventive methods for producing such material are also disclosed.

The major operator of oil and gas pipelines in the North and Norwegian Seas has used different coating systems for external corrosion protection. Presented herein is the company`s experience with cathodic protection design, fabrication, and installation of anodes for deep water pipelines. The cathodic protection (CP) systems for the pipelines are based on using sacrificial anodes. Because the design of the CP system and purchase of sacrificial anodes are carried out early in the development of projects, the CP and anode design are often not optimal. In many projects, flexibility is required during production and installation of anodes.

Ceramic interconnect technology has been adapted to new structures. In particular, the ability to customize processing order and material choices in Low Temperature Cofired Ceramic (LTCC) has enabled new features to be constructed, which address needs in MEMS packaging as well as other novel structures. Unique shapes in LTCC permit the simplification of complete systems, as in the case of a miniature ion mobility spectrometer (IMS). In this case, a rolled tube has been employed to provide hermetic external contacts to electrodes and structures internal to the tube. Integral windows in LTCC have been fabricated for use in both lids and circuits where either a short term need for observation or a long-term need for functionality exists. These windows are fabricated without adhesive, are fully compatible with LTCC processing, and remain optically clear. Both vented and encapsulated functional volumes have been fabricated using a sacrificial material technique. These hold promise for self-assembly of systems, as well as complex internal structures in cavities, micro fluidic and optical channels, and multilevel integration techniques. Separation of the burnout and firing cycles has permitted custom internal environments to be established. Existing commercial High Temperature Cofired Ceramic (HTCC) and LTCC systems can also be rendered to have improved properties. A rapid prototyping technique for patterned HTCC packages has permitted prototypes to be realized in a few days, and has further applications to micro fluidics, heat pipes, and MEMS, among others. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000.

... the best support. Casts can be made of plaster or fiberglass — a plastic that can be shaped. ... on, take off, and adjust. Materials Fiberglass or plaster materials form the hard supportive layer in splints ...

Fibre Metal Laminates (FMLs) are hybrid materials, which consist of thin metal sheets bonded together with alternating unidirectional fibre layers. This material concept has resulted in superior fatigue characteristics with respect to the metallic counterpart. Several static characteristics are howe...

of lightweight materials, such as fiber reinforced polymer matrix composites can lead to ... Research in the Polymeric Materials Branch at NASA Glenn is focused on ..... Layered Silicate and CNT. ? .... ensors; Optical, Magnetic and Electronic. – ...

A photosensitive cell includes an anode and a cathode; a donor-type organic material and an acceptor-type organic material forming a donor-acceptor junction connected between the anode and the cathode; and an exciton blocking layer connected between the acceptor-type organic material of the donor-acceptor junction and the cathode, the blocking layer consisting essentially of a material that has a hole mobility of at least 10.sup.-7 cm.sup.2/V-sec or higher, where a HOMO of the blocking layer is higher than or equal to a HOMO of the acceptor-type material.

material upward from the underlying convective zone. Observations .... enlarge this chart and data table and complete this activity ..... Label the 4 inner layers and 2 outer layers of the Sun in the box for the layer you are labeling. ...... sions, blackouts/power outages on Earth, and emissions of dangerous radioactive particles ...

A new material consisting of a multilayer crystalline structure which is coherent perpendicular to the layers and where each layer is composed of a single crystalline element. The individual layers may vary from 2.ANG. to 100.ANG. or more in thickness.

Pure and doped niobium oxide (Nb2O5) layers are electrochromic (EC) materials which change their colour by insertion of Li+ ions from transparent to brown, grey or blue depending on the crystallinity of the layer. EC-devices with the configuration K-glass / EC-layer / composite electrolyte / Ion-sto...

A new class of structured dielectric media which exhibit significant photonic bandstructure has been invented. The new structures, called photonic layered media, are easy to fabricate using existing layer-by-layer growth techniques, and offer the ability to significantly extend our practical ability to tailor the properties of such optical materials.

A solar cell roof tile includes a front support layer, a transparent encapsulant layer, a plurality of interconnected solar cells and a backskin layer. The front support layer is formed of light transmitting material and has first and second surfaces. The transparent encapsulant layer is disposed adjacent the second surface of the front support layer. The interconnected solar cells has a first surface disposed adjacent the transparent encapsulant layer. The backskin layer has a first surface disposed adjacent a second surface of the interconnected solar cells, wherein a portion of the backskin layer wraps around and contacts the first surface of the front support layer to form the border region. A portion of the border region has an extended width. The solar cell roof tile may have stand-offs disposed on the extended width border region for providing vertical spacing with respect to an adjacent solar cell roof tile.

A passivating overcoat bilayer is used for multilayer reflective coatings for extreme ultraviolet (EUV) or soft x-ray applications to prevent oxidation and corrosion of the multilayer coating, thereby improving the EUV optical performance. The overcoat bilayer comprises a layer of silicon or beryllium underneath at least one top layer of an elemental or a compound material that resists oxidation and corrosion. Materials for the top layer include carbon, palladium, carbides, borides, nitrides, and oxides. The thicknesses of the two layers that make up the overcoat bilayer are optimized to produce the highest reflectance at the wavelength range of operation. Protective overcoat systems comprising three or more layers are also possible.

A device (10) having a ceramic thermal barrier coating layer (16) characterized by a microstructure having gaps (18) with a sintering inhibiting material (22) disposed on the columns (20) within the gaps (18). The sintering resistant material (22) is stable over the range of operating temperatures of the device (10) and is not soluble with the underlying ceramic layer (16). For a YSZ ceramic layer (16) the sintering resistant layer (22) may preferably be aluminum oxide or yttrium aluminum oxide, deposited as a continuous layer or as nodules.

A probe for a surface-enhanced Raman scattering spectrometer includes a member of optically transmissive material for receiving the excitation radiation from a laser and for carrying the radiation emitted from a specimen to a detector. An end of the member for placing against the specimen has a coating that produces surface enhancement of the specimen during Raman scattering spectroscopic analysis. Specifically the coating is formed by a first layer of microparticles on the member and a metal layer over the first layer. The first layer may form a microstructure surface over which a metal layer is applied. Alternatively the coating may be a material containing microparticles of a metal. An optional layer of a material may be applied to the metal layer to concentrate onto the probe compounds of analytical interest onto the probe.

Layered silicates with three-dimensional microporosity within the layers have the potential to enable new applications in catalysis, adsorption and ion-exchange. Until now no such materials have been reported. However, here we present the synthesis and structure of AMH-3, a silicate with three-dimensionally microporous layers, obtained in high purity and crystallinity. AMH-3 is composed of silicate layers containing eight-membered rings in all three principal crystal directions, and spaced by strontium cations, sodium cations and water molecules. Because of its three-dimensional pore structure, acid and thermal stability, this layered material could find applications in polymer-silicate composites for membrane applications, for synthesis of combined microporous-mesoporous materials, and for the formation of new zeolites and microporous films. Its existence also opens new possibilities for the synthesis of other layered silicates with multidimensional microporous framework layers.

Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector.

The invention refers to thermal insulation for high temperature cells etc. According to the invention, the insulating material is formed of three layers, which are manufactured from glass fibres. The glass fibres are manufactured from different glass materials. Each layer contains a different sort of glass fibre. (Outer layer: Alkali lead silicate glass; middle layer: Soft boron silicate glass; inner layer: hard boron silicate glass). The layers are arranged after one another at right angles to the temperature gradients, so that they are in direct contact with each other. The outer layer is adjacent to the inner surface of the outer case wall, while the inner layer is adjacent to the outer surface of the inner wall.

This report presents a study on the effect of material processing parameters used in layer-by-layer material construction on the surface finish of a model to be used as an investment casting pattern. The data presented relate specifically to fused deposition modeling using a machinable wax.

We present an analysis of acoustic cloaks based on the homogenization of two fluidlike materials, with an emphasis on periodically layered imperfect cloaks, by removing the singularities of the acoustic parameters required for ideal cloaks. The conditions that material layers should satisfy are systematically analyzed and critically discussed according to their feasibility.

A quantum coherent switch having a substrate formed from a density wave (DW) material capable of having a periodic electron density modulation or spin density modulation, a dielectric layer formed onto a surface of the substrate that is orthogonal to an intrinsic wave vector of the DW material; and structure for applying an external spatially periodic electrostatic potential over the dielectric layer.

A composite including a plurality of metal layers has a Cu-Al-Fe bronze layer and at least one outer layer of a heat and corrosion resistant metal alloy. The bronze layer is ordinarily intermediate two outer layers of metal such as austenitic stainless steel, nickel alloys or alloys of the refractory metals. The composite provides a barrier to hydrogen isotopes, particularly tritium that can reduce permeation by at least about 30 fold and possibly more below permeation through equal thicknesses of the outer layer material.

Large, uniform hollow spherical shells are produced by forming uniform size drops of heat decomposable or vaporizable material, evaporating the drops to form dried particles, coating the dried particles with a layer of shell forming material, and heating the composite particles to melt the outer layer and decompose or vaporize the inner particle to form an expanding inner gas bubble which expands the outer layer. By cycling the temperature and pressure on the hollow shells, spherical shells with uniform walls are produced.

Flexible and transparent polymeric "superbarrier" packaging materials have become increasingly important in recent years. Layer-by-layer assembly offers a facile technique for the fabrication of layered, polymer-clay superbarrier thin films. At only 51 nm thick, these nanocomposite thin films, comprised of 12 polymer and 4 clay layers, exhibit an oxygen permeability orders of magnitude lower than EVOH and SiO(x). Coupling high flexibility, transparency, and barrier protection, these films are good candidates for a variety packaging applications. PMID:21047123