UK PubMed Central (United Kingdom)

BackgroundTitanium and titanium alloys are widely used for fabrication of dental implants. Since the material composition and the surface topography of a biomaterial play a fundamental...Full Text Available

International Nuclear Information System (INIS)

Titanium and its alloy Ti6Al4V enjoy widespread use in various biomedical applications because of favourable local tissue response, higher corrosion resistance and fatigue strength than the stainless steels and cobalt-chromium alloy previously used. The study reported in this paper aims to optimize the conditions of nitrogen ion implantation on commercially pure titanium and to correlate the implantation parameters to the corrosion resistance. X-ray photoelectron spectroscopy was used to analyse surface concentration and the implantation processes. An improvement in the electrochemical behaviour of the passive film was shown to occur with nitrogen ion implantation on titanium, in simulated body fluids. (UK).

British Library Electronic Table of Contents (United Kingdom)

ABSTRACT Purpose: The aim of this two-center study was to evaluate screw-type titanium implants with a chemically modified, sandblasted and acid-etched surface when placed in the posterior maxilla or mandible, and loaded 21 days after placement. Material and Methods: All 56 patients met strict inclusion criteria and provided informed consent. Each patient displayed either a single-tooth gap, an extended edentulous space, or a distal extension situation in the posterior mandible or maxilla. Eighty-nine dental implants (SLActive, Institut Straumann AG, Basel, Switzerland) were inserted according to an established nonsubmerged protocol and underwent undisturbed healing for a period of 21 days. Where appropriate, the implants were loaded after 21 days of healing with provisional restorations i...

International Nuclear Information System (INIS)

Samples of 316L stainless steel, Vitalium and Ti6A14V titanium alloy have been implanted with doses of 1.5, 3, and 4.5 x 10"1"7 Si"+/cm"2. Transmission electron microscopy shows that during ion implantation amorphous layers are formed. When samples of titanium alloy were implanted with a dose of 0.5 x 10"1"7 Si"+/cm"2, the implanted layer consisted of a dispersion of fine silicide crystallites instead of being amorphous. The corrosion resistance was analyzed by electrochemical techniques in 0.9% NaCl at the temperature of 37 C. The increase of corrosion resistance has been observed as a result of structural modifications of the surface layer. (author). 7 refs, 4 tabs.

Energy Technology Data Exchange (ETDEWEB)

The purpose of this investigation was to simulate a machining front from an abrasive waterjet and its movements in a ceramic material. Wear factors affecting the abrasive waterjet nozzle were also to be established. Therefore, a low inclination angle (9[degree]) was used between the nozzle and test sample, simulating a moving machine front. A standard nozzle with an inner diameter of 0.76 mm was used in the test, and it was placed close to the samples. The outer diameter of the abrasive nozzle was 9.5 mm. The high wear rate from abrasive waterjets makes it possible to machine hard ceramics-including dense alumina, titanium boride, silicon nitride, and composites-at high machining speeds.

International Nuclear Information System (INIS)

SP-700, an emerging #beta#-rich #alpha#+#beta# titanium alloy, is designed to improve superplastic formability as well as mechanical properties over Ti-6Al-4V alloy. Owing to its fine microstructure and low #beta#-transus temperature, it is superplastic-formable at temperature below 1,073K (800 C) with low flow stress. Remarkable workability of this alloy is also retained in conventional Manufacturing processes. Another advantage of SP-700 is heat treatment response which includes deep hardenability and quick aging kinetics. Corrosion resistance and machinability are equivalent to or better than Ti-6Al-4V alloy.

Science.gov (United States)

Natural bone consists of hard nanostructured hydroxyapatite (HA) in a nanostructured protein-based soft hydrogel template (ie, mostly collagen). For this reason, nanostructured HA has been an intriguing coating material on traditionally used titanium for improving orthopedic applications. In addition, helical rosette nanotubes (HRNs), newly developed materials which form through the self-assembly process of DNA base pair building blocks in body solutions, are soft nanotubes with a helical architecture that mimics natural collagen. Thus, the objective of this in vitro study was for the first time to combine the promising attributes of HRNs and nanocrystalline HA on titanium and assess osteoblast (bone-forming cell) functions. Different sizes of nanocrystalline HA were synthesized in this study through a wet chemical precipitation process following either hydrothermal treatment or sintering. Transmission electron microscopy images showed that ...

International Nuclear Information System (INIS)

Intervertebral spacers for anterior spine fusion are made of different materials, such as titanium and cobalt chromium alloys and carbon fiber-reinforced polymers. Implant-related susceptibility artifacts can decrease the quality of MRI scans. The aim of this cadaveric study was to demonstrate the extent that implant-related MRI artifacting affects the postfusion differentiation of determined regions of interest (ROIs). In six cadaveric porcine spines, we evaluated the postimplantation MRI scans of a titanium, cobalt-chromium and carbon spacer that differed in shape and surface qualities. A spacer made of human cortical bone was used as a control. A defined evaluation unit was divided into ROIs to characterize the spinal canal as well as the intervertebral disc space. Considering 15 different MRI sequences read independently by an interobserver-validated team of specialists the artifact-affected image ...

Energy Technology Data Exchange (ETDEWEB)

General trends in integrated circuit technology toward smaller device dimensions, lower thermal budgets, and simplified processing steps present severe physical and engineering challenges to ion implantation. These challenges, together with the need for physically based models at exceedingly small dimensions, are leading to a new level of understanding of fundamental defect science in Si. In this article, we review the current status and future trends in ion implantation of Si at low and high energies with particular emphasis on areas where recent advances have been made and where further understanding is needed. Particularly interesting are the emerging approaches to defect and dopant distribution modeling, transient enhanced diffusion, high energy implantation and defect accumulation, and metal impurity gettering. Developments in the use of ion beams for analysis indicate much progress has been made in one-dimensional ...

Energy Technology Data Exchange (ETDEWEB)

To improve the surface properties of magnesium alloy, a lining process using shot peening was carried out. The lining of magnesium alloy with metals such as titanium and nickel is useful in heightening the corrosion and wear properties for the components. In the shot peening experiment, the foil set on the magnesium workpiece is pelted with many shots at a high velocity. The foil is bonded to the surface of the workpiece due to plastic deformation induced by the collision of the shots. A pure aluminum foil is inserted between the hard foil and magnesium workpiece to assist the bonding. To heighten the bondability, the foil and workpiece are heated and the flow stresses of the metals are reduced. In this experiment, a centrifugal shot peening machine with an electrical heater was employed. The workpieces were commercially magnesium alloys AZ31B and AZ91D, and the foils were commercially pure aluminum, pure titanium and pure ...

International Nuclear Information System (INIS)

Zirconium is a transition element located along with sister elements titanium and hafnium in Group IVB of the periodic table. It is grayish white metal, with a density somewhat less than carbon steel. Zirconium is the ninth most common metallic element in the earth's crust, and is more abundant than zinc, lead, nickel, or even copper. Zirconium is exceptionally resistant to corrosion by many common acids and alkalis. It is resistant to most organic acids, such as formic, acetic, lactic, and oxalic acids. It also has a high resistance to localized forms of corrosion, such as pitting, crevice corrosion, and stress corrosion cracking. Its corrosion resistance is caused by the formation of a dense, tenaciously adherent, chemically inert oxide film on the surface. This oxide film protects the base metal from both chemical and mechanical attack at temperatures up to about 400 C (750 F). This article describes zirconium's formability, machinability, ...

International Science & Technology Center (ISTC)

The New Titanium Alloys With Increased Mechanical Properties and Corrosion Resistance for Medical Instruments and their Coatings

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Science & Technology Center (ISTC)

Development of Oxygen Ion-Implanted Collector materials for Thermal Emission Converters of Thermal Energy into the Electric One.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

PMID:17346598

International Nuclear Information System (INIS)

For optimizing the microstructure of the (#alpha# + #beta#)-titanium alloy TiAl5Fe2.5 the content of the two alloying elements aluminium and iron in the #alpha#- and #beta#-phase was determined by microprobe analysis. The alloys with the composition of the #alpha#- and of the #beta#-phase at 850 degC TiAl6Fe0.5 (#alpha#-phase) and TiAl3.5Fe6.5 (#beta#-phase) were prepared by arc melting and rolling at 850 degC. The mechanical properties of the '#alpha#'- and of the '#beta#'-phase-alloy are compared with the properties of the (#alpha# + #beta#)-alloy TiAl5Fe2.5 in the as rolled and swaged condition and after an additional aging at 550 degC. By this optimizing process it was possible to achieve a tensile strength of Rsub(m) = 1012 N/mm"2, an yield strength of Rsub(p0.2) 954 N/mm"2 and an elongation at fracture A = 14.5% in the TiAl5Fe2.5-alloy, although the degree of hot deformation was small. By a higher degree of deformation these properties can be improved. ...

Science.gov (United States)

Based on a recent investigation that modeled the elastic properties (ie, strength, stiffness and range) of multistranded wires made from linearly elastic materials, three-stranded (triple) and six-stranded coaxial (coax) stainless steel (SS) wires were compared to single-stranded (single) SS and conventional nickel titanium (NiTi) leveling wires. To measure Young's modulus of elasticity (E), flexural tests were performed with an Instron mechanical testing machine in a three-point bending arrangement having a span length of 8.9 mm or 12.5 mm. A strong correlation between wire stiffness and the area moment of inertia demonstrated that strand interaction was negligible at low activations and that E = 199 GPa was constant even for the heavily drawn coax strands. Using the Instron with an extensometer, the 0.1% yield strengths (sigma(YS)) of the single SS wires and the straight inner strands within the coax wires were tested. The ratio of the ...

Energy Technology Data Exchange (ETDEWEB)

The current--density profile of a focused ion beam (FIB) has a central peak accompanied by broader ``wings`` that, while unimportant in lithographic applications, can lead to unwanted effects during an implantation operation. The origin of the wings, and hence the best way to minimize them, is not clear and needs further study. We have measured the line profiles of several of the ions available in our FIB machine as a function of a number of variables, under ultrahigh vacuum (UHV) conditions. No effects are observed from changes in emission current or deliberate defocusing of the objective lens. There are some changes with beam aperture and/or current, but the biggest differences seem to be associated with a change of source type and hence, possibly, with a change in the source/extractor configuration or in the alloy and the emission process. The wing amplitudes are appreciably lower than many previously observed, and their profiles, at least ...

Science.gov (United States)

PMID:4317460

International Nuclear Information System (INIS)

This paper describes a process for the direct production of a superconductive niobium-titanium alloy during reduction of niobium pentoxide. It comprises: mixing at least one of titanium metal powder and titanium dioxide powder with niobium pentoxide powder and aluminum powder; heating the resulting mixture to form a niobium-titanium alloy and a slag consisting essentially of aluminum oxide; and separating the alloy and the slag.

Energy Technology Data Exchange (ETDEWEB)

The possibility of rapid heat treatment (RHT) application to titanium castings has been studied. It was shown that such treatment provides a significant improvement of intragrain structure and mechanical properties of cast ({alpha}+{beta})-titanium alloys. ((orig.))

Science.gov (United States)

... Accession Number : ADD815206. Title : Waterjet Cutting System Adds Value to Titanium Parts. Descriptive Note : Journal article. Corporate Author : ...

Science.gov (United States)

... Accession Number : ADD109273. Title : THERMAL STABILITY OF ALPHA-BETA TITANIUM ALLOY Ti-5Al-2Cr-1Fe,. Corporate Author : ...

International Nuclear Information System (INIS)

Consideration is given to the process of the formation of a titanium sponge alloyed with niobium or tantalum, in the joint metallic reduction of titanium, niobium and tantanum chlorides. A percentage composition of the phases observed and the structure of the alloyed sponge have been studied. It is shown that after one remelting operation of the alloyed sponge the alloys of titanium with niobium and tantalum have a uniform component distribution. At the stage of chloride reduction there appear solid solutions based on titanium and an alloying component. The stage of vacuum separation of the reaction mass is associated with a mutual dissolution of the primary phases and the formation of the solid solutions of the alloyed titanium sponge, which, by their composition, are close to the desired alloy composition. The principal features of the formation of a titanium ...

Science.gov (United States)

... Accession Number : ADD120492. Title : Environmental Cracking of the Alpha-Beta Titanium Alloy, Ti-6Al-6V-2Sn,. Corporate ...

Science.gov (United States)

... Title : DUCTILITY RATIO OF AGED BETA TITANIUM ALLOY. Corporate Author : NEW YORK UNIV NY SCHOOL OF ENGINEERING AND SCIENCE. ...

International Nuclear Information System (INIS)

Observations concerned with the formation of isothermal #omega# in the beta-titanium alloy RMI (38-6-44) are presented as part of a more general study of the aging characteristics of the alloy.

Energy Technology Data Exchange (ETDEWEB)

The loosening equipment consists of a base machine and four-link suspension mechanism which is a cross frame with loosening gear connected to the base machine by universal hinges. In order to improve the reliability of the machine, the drive of transverse shifting in the cross frame is made of symmetrically arranged, shock-absorbing, hydraulic cylinders which are connected by additional universal hinges to the base machine and the lower pull rods. The design of the loosening machine guarantees its reliable operation on soil with significant quantity of hard inclusions.

International Nuclear Information System (INIS)

Short communication.

Science.gov (United States)

Not Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

In this paper a study is made of the structure and mechanical properties of the #beta# alloy system Ti-Mo-Zr-Sn (the composition of which is equivalent to the #beta# III alloy used abroad) containing different amounts of carbon. Study of the #beta#-titanium alloy containing 0.1% C revealed the presence of particles of titanium carbide. Separation of the titanium carbide promotes a reduction in impact strength, an increased tendency toward cold shortness, and poorer workability. (author).

Energy Technology Data Exchange (ETDEWEB)

Plasma nitriding was applied to improve the surface performance of titanium bipolar plate. XRD and SEM results showed a titanium nitride layer was formed after nitridation. In comparison with pure titanium, the interfacial contact resistance of plasma nitrided titanium was reduced to some extent by the nitridation treatment. However, high corrosion current was observed under electrochemical tests in 0.5 M H{sub 2}SO{sub 4} + 5 ppm HF. Both the electrical conductivity and corrosion resistance of the surface of plasma nitriding titanium did not reach the level of graphite. Some more improvements are expected in the plasma nitriding process or another surface modification on pure titanium. (author)

UK PubMed Central (United Kingdom)

BackgroundThe successful use of zirconia ceramics in orthopedic surgery led to a demand for dental zirconium-based implant systems. Because of its excellent biomechanical characteristics,...Full Text Available

UK PubMed Central (United Kingdom)

This article describes issues concerning music perception with cochlear implants, discusses why music perception is usually poor in cochlear implant users, reviews relevant data, and describes...Full Text Available

Science.gov (United States)

... Accession Number : ADB006226. Title : Electrical Discharge Machining (EDM) Gun Barrel Bore and Rifling Feasibility Study. ...

UK PubMed Central (United Kingdom)

A comparison of the results of machine and human information retrieval using MEDLARS and the printed Index Medicus indicates that at present neither method is entirely satisfactory...Full Text Available

UK PubMed Central (United Kingdom)

Fluorescein angiography of the iris was performed on patients with plastic lens implants with cystoid oedema of the macula, and the nature of the vascular changes was compared with controls provided...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The objective of the investigation was to study the feasibility of applying continuous casting steel 100Cr6 (SAE 52100) for bearing balls. It was found that two of three continuous casted steel batches have longer or at least similar rolling contact fatigue lifetimes compared to one ingot casted batch. For one of the continuous casted batches, the rolling contact fatigue lifetime was 30% less. The micro- and macrostructure and the residual stresses below the surface of the balls were comparable. There is also no obvious difference between the four batches in the metallurgical parameters like contents of oxygen, titanium and sulfur as well as in the distribution of carbides and their network. The reason for the shorter lifetime of one batch finally was found to be due not to the continuous casting process itself. There was a difference in the cross section of the different casting moulds, and by this in the speed of solidification. As a consequence an increased ...

British Library Electronic Table of Contents (United Kingdom)

Statement of problem Computer-aided design/computer-aided manufacturing (CAD/CAM) titanium ceramic restorations were developed with the potential for replacing expensive, high noble metal ceramic restorations. However, there is a lack of information about the clinical performance of CAD/CAM titanium ceramic single crowns. Purpose The purpose of this study was to evaluate CAD/CAM titanium ceramic single crowns after 3 years in function. Material and methods A total of 41 crowns were fabricated for 21 patients. The titanium copings were CAD/CAM milled (Everest CAD/CAM system) with an even thickness of 0.5 mm, and low-fusing veneering porcelain (Vita Titanium Porcelain) was added incrementally. The crowns were cemented using zinc phosphate cement after confirming that there were no mechanical...

Science.gov (United States)

For abstract, see NSA 27 06, number 14465.

Science.gov (United States)

Cardiac Arrest; Cardiopulmonary Resuscitation

Energy Technology Data Exchange (ETDEWEB)

This article considers the fundamentals of what happens in asolid when it is impacted with a medium energy gallium ion. The study ofthe ion/sample interaction at the nanometer scale is applicable to mostfocused ion beam (FIB) based work even if the FIB/sample interaction isonly a step in the process, e.g., micromachining or microelectronicdevice processing. Whereas the objective in other articles in this issueis to use the FIB tool to characterize a material or to machine a deviceor transmission electron microscopy (TEM) sample, the goal of the FIB inthis article is to have the FIB/sample interaction itself become theproduct. To that end, the FIB/sample interaction is considered in threecategories according to geometry: below, at, and above the surface.First, the FIB ions can penetrate the top atom layer(s) and interactbelow the surface. Ion implantation and ion damage on flat surfaces havebeen comprehensively examined; however, FIB ...

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

The pitting corrosion resistance of three different types of stainless steel implanted with silicon is investigated using the potentiokinetic polarization technique. The specimens are tested in 3% NaCl and 0.1 N HCl solutions. Silicon ion implantation inhibits pitting corrosion of the steels in both aqueous media. The corrosion resistance depends on the silicon dose. Post implantation annealing only slightly alters the localized corrosion. (author).

International Nuclear Information System (INIS)

The point-defect-impurity pair diffusion model proposed recently by Mulvaney and Richardson is adopted and modified to simulate the coupled diffusion of phosphorus and self-interstitials in phosphorus-implanted silicon. The assumption of implantation-induced, but empirically determined initial interstitial distributions of Gaussian shape allows a simulation of the net effect of transient enhanced diffusion. As a result an improved modeling of phosphorus diffusion in silicon is achieved for a broad range of ion-implantation and annealing conditions. (author).

Science.gov (United States)

Not Available

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A virtual balancing axis arrangement is described for multi-cylinder reciprocating piston machines for effectively balancing out imbalanced forces and minimizing residual imbalance moments acting on the crankshaft of such machines without requiring the use of additional parallel-arrayed balancing shafts or complex and expensive gear arrangements. The novel virtual balancing axis arrangement is capable of being designed into multi-cylinder reciprocating piston and crankshaft machines for substantially reducing vibrations induced during operation of such machines with only minimal number of additional component parts. Some of the required component parts may be available from parts already required for operation of auxiliary equipment, such as oil and water pumps used in certain types of reciprocating piston and crankshaft machine so that by appropriate location and dimensioning in ...

International Nuclear Information System (INIS)

Electrical properties of 16 keV, focused-ion-beam (FIB) (beam diameter: 1 #mu#m, current density: 50 mA/cm"2) boron-implanted silicon layers have been investigated as a function of beam scan speed and ion dose, and compared with those obtained by conventional implantation (current density: 0.4 #mu#A/cm"2). High electrical activation of the FIB implanted layers is obtained by annealing below 800"0C as a result of the increase in amorphous zones created in the implanted layers. Amorphous zone overlapping is assumed to occur at FIB implantation doses of 3 - 4 x 10"1"5 ions/cm"2 from the results of electrical activation and the carrier profile of implanted regions annealed at low temperature, if beam scan speed is lowered to about 10"-"2 cm/s. (author).

International Nuclear Information System (INIS)

The effect of Al and Be ions pre-implantation on microstructural change and, the formation and growth of He bubbles in SiC/SiC composite was investigated. Four kinds of ion implanted specimens were prepared with 100 appm Al, 1000 appm Al, 100 appm Be and 1000 appm Be implanted. No microstructural change was observed in the matrices and fibers of SiC/SiC composites implanted with Al or Be ions up to 1000 appm. The un-implanted and Al or Be pre-implanted SiC/SiC composites were simultaneously irradiated to 10 dpa using triple ion-beams (6.0-MeV Si"2"+, 1.0-MeV He"+ and 340-keV H"+) at 1000 deg. C. Helium bubbles were formed in every matrix and fiber irradiated by triple ion-beams. The size of He bubbles in the matrix was increased by implanting Al or Be ions and increased with increasing amount of implanted Al or Be ions. ...

Science.gov (United States)

Probabilistic sensitivities using the score function method are developed for a lifing analysis of an alpha + beta titanium alloy in a round bar under axial fatigue load. Sensitivities with respect to the statistical inputs of the crack initiation size (a...

Science.gov (United States)

Quantitative metallography is often used to confirm the proper processing of aerospace metallic materials. A microstructural feature of great importance for titanium alloys processed in the alpha-beta phase field is the volume fraction of primary alpha. S...

International Nuclear Information System (INIS)

... properties organic bromine compounds organic solvents ph value phenols

International Nuclear Information System (INIS)

17-4PH stainless steel was modified by direct current (DC) plasma nitriding and titanium nitride film duplex treatment in this study. The microstructure, wear resistance and corrosion resistance were characterized by X-ray diffraction (XRD), pin-on-disk tribological test and polarization experiment. The results revealed that the DC plasma nitriding pretreatment was in favor of improving properties of titanium nitride film. The corrosion resistance and wear resistance of duplex treatment specimen was more superior to that of only coated titanium nitride film.

International Nuclear Information System (INIS)

1970. United States Crossley, FA Lindberg, RW Lockheed Missiles and

Science.gov (United States)

... Accession Number : ADD100229. Title : DEFORMATION BEHAVIOR OF AN OMEGA HARDENED ALPHA-BETA TITANIUM ALLOY,. ...

Science.gov (United States)

... Accession Number : ADA136144. Title : Characteristics of the Mechanical Properties and the Fractures of an Alpha Beta Titanium Alloy,. ...

Science.gov (United States)

A number of alloys of zirconium have been investigated as part of a program aimed at improving the high-temperature tensile and creep strength of zirconium. These alloys include aluminum, beryllium, lead, magnesium, molybdenum, niobium, tantalum, tin, titanium, tungsten, vanadium, and zinc, binary and ternary alloys. The data indicate that aluminum, lead, molybdenum niobium, tin, titanium, tungsten, and vanadium can be used successfully to harden zirconium, and that aluminum, tin, titanium, and vanadium are particularly effective in maintaining the strength of zirconium at elevated temperatures.

Science.gov (United States)

A beta titanium alloy was evaluated for use in orthodontic appliances. Standard mechanical tests and aspecially designed spring test were used. Two particular thermo-mechanical treatments resulted in titanium springs with 1.8 times the extension of comparable stainless steel springs, and a 2.2 fold reduction in force per unit displacement. PMID:283089

International Nuclear Information System (INIS)

Austenitic stainless steels have been implanted with molybdenum ions (Mo"+, 100 keV, 2.5 x 10"1"6 atoms cm"-"2). The implanted material has been characterized by XPS and RBS. The implanted region has a thickness of #approx# 1000 A with a maximum molybdenum concentration of #approx# 9 at.% Mo located at #approx# 210 A from the surface. The effects of implanted molybdenum on the passivation of the alloy in 0.5 M H_2SO_4 have been investigated by electrochemistry and XPS. After XPS analysis the samples were transferred without exposure to air into a glove-box with an inert atmosphere. The electrochemical behaviour of the alloy is significantly modified by the implanted molybdenum. The major effect is that the activation peak disappears. A bilayer structure (outer hydroxide/inner oxide) of the passive film is observed for both the implanted and ...

International Nuclear Information System (INIS)

A low-molybdenum austenitic stainless steel (UNS S30100) has been surface implanted with molybdenum ions, using various doses of 50 keV and 140 keV ions at room temperature. It is found that in aqueous sulphate/chloride solutions similar to the constitution of sea-waters the implantation does not affect the potentiostatically-determined critical pitting potential, but does change the density and morphology of corrosion pits. Pitting initiation after the addition of chloride at a fixed potential indicates little change in the time for measurable current increase, but the rate of increase of the current is much lower for implanted material. Detailed examination using optical microscopy, scanning electron microscopy, transmission electron microscopy and selected area diffraction suggests that the pits produced in implanted material are hemispherical with smooth covers of unattacked alloy. The use of ...

British Library Electronic Table of Contents (United Kingdom)

Nowadays there are many sun-protection cosmetics incorporating organic or inorganic UV filters as active ingredients. Chemically stable inorganic sunscreen agents, usually metal oxides, are widely employed in high-SPF (sun protection factor) products. Titanium dioxide is one of the most frequently used inorganic UV filters. It has been used as a pigment for a long period of cosmetic history. With the development of micronization techniques, it has become possible to incorporate titanium dioxide in sunscreen formulations without the previous whitening effect, and hence its use in cosmetics has become an important research topic. However, there are very few works related to quantitation of titanium dioxide in sunscreen products. In this research, we analysed the amounts of titanium dioxide i...

British Library Electronic Table of Contents (United Kingdom)

Machine-to-machine (M2M) communications is a new and rapidly developing technology for large-scale networking of devices without dependence on human interaction. Energy efficiency is one of the important design objectives for machine-to-machine network architectures that often contain multi-hop wireless subnetworks. Constructing energy-efficient routes for sending data through such networks is important not only for the longevity of the nodes which typically depend on battery energy, but also for achieving an environmentally friendly system design overall, which will be imperative as M2M networks scale in number of nodes as projected. The objective of this survey is to provide a comprehensive look into shortest-path based energy-efficient routing alternatives to provide a reference for sys...

International Nuclear Information System (INIS)

The indium implant damage and diffusion behavior in thin silicon-on-insulator (SOI) with a 200 nm top silicon layer were studied for different implantation energies and doses. Rutherford backscattering spectrometry in the channeling mode (RBS/C) was used to characterize the implant damage before and after annealing. Secondary ion mass spectrometry (SIMS) was used to study the indium transient enhanced diffusion (TED) behavior in the top Si layer of the SOI structure. An anomalous redistribution of indium after relatively high energy (200 keV) and dose (1 x 10"1"4 cm"-"2) implantation was observed in both bulk Si and SOI substrates. However, there exist differences in these two substrates that are attributable to the more predominant out-diffusion of indium as well as the influence of the buried oxide layer in the SOI structure.

International Nuclear Information System (INIS)

The effects of O and C ion implantation with different implantation doses on the yellow luminescence (YL) from unintentional doped n-type GaN have been studied by the photoluminescence (PL) spectra. O and C ions were implanted in the GaN samples with different doses from 1.0 x l013 to 1.0 x l017cm-2. Post-annealing was done in a quartz open-tube furnace under flowing N2 gas for 30 min at 950 degree C. By comparing with N ion implanted samples, it is assumed that different deep-level centers involving in the YL were produced in GaN after O and C ion implantation. In addition, with a dose of 1017 cm-2, the concentration of deep C centers involving in the YL was enhanced markedly. (authors)

Science.gov (United States)

A 12-month program was conducted to advance the technology of the Electrical Discharge Machining (EDM) process to be applicable to the stringent requirements of gun barrel boring and rifling. The type of barrels employed in the test were .220 swift gun ba...

Energy Technology Data Exchange (ETDEWEB)

We measure the transient enhanced diffusion of shallow molecular-beam-epitaxy grown marker layers of Sb and B due to deep MeV Si{sup +} ion implants at very high doses ({approx}10{sup 16}cm{sup {minus}2}). We expect the near-surface region of these implants to be vacancy rich, and we observe transient enhanced diffusion of Sb (the classic vacancy diffuser). The large enhancements imply a significant vacancy supersaturation ({approx}700 at 740{degree}C). Double implantation of the high-dose MeV Si followed by a shallow (40 keV) Si implant and annealing produces a greatly reduced number of {l_brace}311{r_brace} defects compared to a 40 keV implant into virgin Si, again consistent with a vacancy-rich region in the near-surface region of an MeV implant. However, the shallow B marker layers also show transient enhanced diffusion for the same MeV ...

International Nuclear Information System (INIS)

In this paper, we report the systematic investigation on the melt characteristics of silicon during laser thermal processing (LTP) of amorphous silicon (a-Si) gates on ultrathin gate oxides. LTP is used to reduce the gate depletion effect in advanced semiconductor devices. The influence of implantation-induced damage and chemical inhomogeneities on the melt behavior of ion-implanted a-Si is studied using in situ time-resolved reflectance (TRR) measurements and ex situ secondary ion mass spectrometry. The results from TRR measurements indicate the presence of a buried melt for a-Si implanted with B"+ at a subamorphizing dose. In contrast, such a melt behavior is not observed during LTP of undoped a-Si and a-Si implanted with As"+ at an amorphizing dose. We attribute the marked difference in the melt characteristics to the competitive effects between compositional inhomogeneities and the extent of ...

Energy Technology Data Exchange (ETDEWEB)

Combining in situ Rutherford backscattering and electrical transport measurements on low-temperature hydrogen-implanted amorphous Pd/sub 80/Si/sub 20/ films, we have studied the correlation between the hydrogen content and the resistivity.

UK PubMed Central (United Kingdom)

Nowadays, percutaneous pulmonary valve implantation is a successful alternative to surgery for patients requiring treatment of pulmonary valve dysfunction. However, owing to the wide variety of implantation...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

We demonstrate that the excess vacancies induced by a 1 MeV Si implant reduce the excess interstitials generated by a 40 keV Si implant during thermal annealing when these two implants are superimposed in silicon. It is shown that this previously observed reduction is dominated by vacancy annihilation and not by gettering to deeper interstitial-type extended defects. Interstitial supersaturations were measured using B doping superlattices (DSL) grown on a silicon-on-insulator (SOI) substrate. Implanting MeV and keV Si ions into the B DSL/SOI structure eliminated the B transient enhanced diffusion normally associated with the keV implant. The buried SiO{sub 2} layer in the SOI substrate isolates the deep interstitials-type extended defects of the MeV implant, thereby eliminating the possibility that these defects getter the interstitial excess induced by the keV ...

UK PubMed Central (United Kingdom)

The effect of feedback and materials on perceptual learning was examined in normal hearing listeners exposed to cochlear implant simulations. Generalization was most robust when feedback paired...Full Text Available

UK PubMed Central (United Kingdom)

The temporal fine structure (TFS) of sound contributes significantly to the perception of music and speech in noise. The evaluation of new strategies to improve TFS delivery in cochlear implants (CIs)...Full Text Available

Science.gov (United States)

After each archwire was ligated into a bracket with a 0.010-in stainless steel wire, both stainless steel and beta-titanium archwires (0.017- x 0.025-in) were slid through commercially pure titanium brackets (0.018-in slot size) at 34 degrees C in both the dry and wet conditions. As controls, stainless steel archwire versus stainless steel bracket couples were used with comparable dimensions. The drawing forces were measured at 5 angulations (0 degrees, 3 degrees, 7 degrees, 9 degrees, and 11 degrees ) for 5 normal forces (nominally 0.2, 0.4, 0.6, 0.8, and 1.0 kg). Regression lines were determined for each frictional couple (P <.05). In the passive configuration, the kinetic frictional coefficients of control and test couples in the dry condition were comparable to previously reported values at 0.11 +/- 0.01 for stainless steel versus stainless steel, 0.12 +/- 0.00 for stainless steel versus titanium, and 0.26 +/- 0.02 ...

KoreaScience (Korea)

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International Nuclear Information System (INIS)

The application of remote handling and robotics, the state of the art and some uses in the man-machine interface are described. (E.G.).

Science.gov (United States)

... space vehicles, robot and machine guidance systems, and in various types of autonomous UUV docking situations. Page 3. ...

Energy Technology Data Exchange (ETDEWEB)

In situ Auger sputter depth profiles of saturation implants of 3 keV N/sub 2//sup +/ in silicon at room temperature exhibit a sharp peak in the nitrogen concentration in the outermost layers, followed by a monotonic decrease. No broad plateau was observed. The energy of the Auger line corresponding to the Si(2p) core electron excitation, monitored throughout the profiling, exhibits a chemical shift of up to 7 eV at the surface peak concentration. Inert gas ion post-bombardment of unsaturated implants significantly modifies the profile, and supports the suggestion that the surface peak arises through radiation enhanced diffusion of implanted atoms.

International Nuclear Information System (INIS)

In this work, we investigate the interstitial injection into the silicon lattice due to high-dose, low-energy arsenic implantation. The approach consists in monitoring the diffusion of the arsenic profile as well as of the boron profile in buried #delta#-doped layers, when amounts of the as-implanted arsenic profile are removed by low-temperature wet silicon etching. The experimental results indicate that the contribution of the implantation damage to the transient enhanced diffusion of boron, and thus the interstitial injection, is not the main one. On the contrary, interstitial generation due to arsenic clustering seems to be more important for the present conditions.

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The theoretical alignment limit for focused ion beam (FIB) implantation was deduced from the calculated resolution for the detection of an alignment mark. The alignment resolution varies with the signal to noise ratio and there is an optimum current which gives the best resolution. The alignment resolution epsilon/sub sigma/ is approximately 0.006 ..mu..m for a 160 keV Si/sup ++/ beam from our FIB implanter. The measured alignment error is approximately 0.06 ..mu..m and the main reason of this discrepancy is vibration. The ultimate limit on the alignment error can be reached through improvements in the implanter system.

Energy Technology Data Exchange (ETDEWEB)

Papers are presented under the session headings: research in mechanical fragmentation; rock characterization, remote sensing and interface detection; monitoring, data transmission and communications; tunnel boring machines; minewide monitoring and expert systems for ground control; machine guidance; shaft and raise boring; automation of drilling equipment; machine automation and control; new developments in mechanical miners; materials handling; innovative mining systems; general minewide monitoring and expert systems; ground support; human factors; and extraterrestrial mining.

Energy Technology Data Exchange (ETDEWEB)

Processes were developed that use lasers as manufacturing tools. These processes were stripping of insulation from cables and wires, machining of quartz, microdrilling and welding of reflective metals, and precision alignment of curved surfaces before machining. A technological basis also was formed which resulted in a process for automatic surface inspection of parts and aided development of machining processes for Kevlar parts.

International Nuclear Information System (INIS)

Amorphization and a dual implant technique have been used to manipulate residual defects that persist following implantation and post-implant thermal treatments. Residual defects can often be attributed to ion-induced defect excesses. A defect is considered to be excess when it occurs in a localized region at a concentration greater than its complement. Sources of excess defects include spatially separated Frenkel pairs, excess interstitials resulting from the implanted atoms, and sputtering. Preamorphizing prior to dopant implantation has been proposed to eliminate dopant broadening due to ion channeling as well as dopant diffusion during subsequent annealing. However, transient-enhanced diffusion (TED) of implanted boron has been observed in pre-amorphized Si. The defects driving this enhanced boron diffusion are thought to be the extended interstitial-type ...

International Nuclear Information System (INIS)

Transient enhanced diffusion in boron-implanted silicon is interpreted as being due to the fact that during rapid thermal annealing a relaxation process takes place, associated with quasi-chemical reactions including defects. A simple analytical model makes it possible to describe the annealing mechanism on a microscopic scale in terms of reaction-diffusion processes. The measured dependences of the boron diffusion coefficient of the enhanced diffusion on time, temperature and implantation energy are satisfactorily explained. (author).

Energy Technology Data Exchange (ETDEWEB)

The project is devoted to the development of novel insoluble anodes for copper electrowinning and electrolytic manganese dioxide (EMD) production. The anodes are made of titanium-lead composite material produced by techniques of powder metallurgy, compaction of titanium powder, sintering and subsequent lead infiltration. The titanium-lead anode combines beneficial electrochemical behavior of a lead anode with high mechanical properties and corrosion resistance of a titanium anode. In the titanium-lead anode, the titanium stabilizes the lead, preventing it from spalling, and the lead sheathes the titanium, protecting it from passivation. Interconnections between manufacturing process, structure, composition and properties of the titanium-lead composite material were investigated. The material containing 20-30 vol.% of ...

International Nuclear Information System (INIS)

The methods of optical and transmission electron microscopy were used to study the influence of different programmes of hot deformation on the structure formation of (#alpha#+#beta#) titanium alloy VT9. The #beta# alloy VT-15 was studied at the same time in order to simulate the dislocation structure generated in the process of hot deformation. During the hot deformation of two-phase titanium alloys in both #beta# and (#alpha#+#beta#) ranges there is found to be an optimum range of deformation in which a homogeneous, polygonized structure is formed.

Science.gov (United States)

The introduction of numerical control (NC) machine tools has made it possible to automate machining in series and small series production. The organization of automated production sections merged NC machine tools with automated transport systems. However, both the one and the other require the presence of an operative at the machine for low skilled operations. Industrial robots perform a number of auxiliary operations, such as equipment loading-unloading and control, changing cutting and auxiliary tools, controlling workpieces and parts, and cleaning of location surfaces. When used with a group of equipment they perform transfer operations between the machine tools. Industrial robots eliminate the need for workers to form auxiliary operations. This underscores the importance of developing robotized manufacturing centers providing for minimal human participation in production and ...

Energy Technology Data Exchange (ETDEWEB)

According to the development of power electronic element (GTO, IGBT) nd material for electrical machines (permanent magnet, super conductor), the technology for electrical machines is now a day rapidly developing. here with, a novel electrical machine, based on the new conception of transverse flux configuration leads to a considerable increase in power density and enables simultaneously high efficiency.The transverse flux machine with PM excitation will be applied to gearless direct drives for railway traction system. The designed and measured performance of transverse machine for railway traction system revealed a great potential of system improvements to reduce linear motor mass. (author). 10 refs., 14 figs., 3 tabs.

International Nuclear Information System (INIS)

Rapid growth in implant applications in the fabrication of semiconductors has encouraged a dramatic increase in the range of energies, beam currents and ion species used. The challenges of a wider energy range, higher beam currents, continued reduction in contamination, improved angle integrity and larger substrates have motivated the development of many innovations. Advanced processes in submicron device production uses up to twenty implantation steps. Thus the outstanding growth of this industry has led to the evolution of a thriving business of hundreds of implantation equipment systems each year with very specific requirements. The present paper reviews the principal process requirements which resulted in the evolution of the equipment technology, and describes the recent trends in the ion implanter technology all three principal categories: high current, medium current and high energy. (author)

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P-implantation (10/sup 17/ ions cm/sup -2/, 40 KeV) into 304 stainless steel (ss) has been carried out, and an amorphous surface alloy was formed. Polarization studies in deaerated 1N H/sub 2/SO/sub 4/+ 2% NaCl showed that P-implantation improved both the general and localized corrosion resistance of 304 ss. A comparative study has been carried out between the implanted and unimplanted steel to determine what influence P-implantation has upon the properties of the passive film formed 1N H/sub 2/SO/sub 4/. The influence of Cl ions on pre-formed passive films was also studied. RHEED, XPS and AES were used to evaluate the nature of the passive films formed in these studies.

Energy Technology Data Exchange (ETDEWEB)

A new technique for ion implantation into concave surface of insulating materials is proposed and experimentally studied. The principle is roughly described by referring to modifying inner surface of a PET (polyethylene terephthalate) bottle. An electrode that is supplied with positive high-voltage pulses is inserted into the bottle. Both plasma formation and ion implantation are simultaneously realized by the same high-voltage pulses. Ion sheath with a certain thickness that depends on plasma parameters is formed just on the inner surface of the bottle. Since the plasma potential is very close to that of the electrode, ions from the plasma are accelerated in the sheath and implanted perpendicularly into the bottle's inner surface. Laser Raman spectroscopy shows that the inner surface of an ion-implanted PET bottle is modified into DLC (diamond-like carbon). Gas permeation measurement shows ...

Energy Technology Data Exchange (ETDEWEB)

A model is presented to account for the effects of ion-induced defects during implantation processing of Si. It will be shown that processing is quite generally affected by the presence of defect excesses rather than the total number of defects. a defect is considered excess if it represents a surplus locally of one defect type over its compliment. Processing spanning a wide range of implantation conditions will be presented to demonstrate that the majority of the total defects played little or no role in the process. This is a direct result of the ease with which the spatially correlated Frenkel pairs recombine either dynamically or during a post-implantation annealing. Based upon this model, a method will be demonstrated for manipulating or engineering the excess defects to modify their effects. In particular high-energy, self-ions are shown to inject vacancies into a boron implanted region resulting ...

British Library Electronic Table of Contents (United Kingdom)

The colonization of an implant surface by bacteria is an extremely important medical problem, which often leads to the failure of medical devices. Modern surface modification techniques, such as ion implantation, can confer to the surfaces very different properties from those of the bulk underlying material. In this work, austenitic stainless steel 316 LVM has been superficially modified by Si^+ ion implantation. The effect of surface modification on the biocompatibility and bacterial adhesion to 316 LVM stainless steel has been investigated. To this aim, human mesenchymal stem cells (hMSCs), as precursor of osteoblastic cells, and bacterial strains relevant in infections related to orthopedic implants, i.e., Staphylococcus aureus and Staphylococcus epidermidis, have been assayed. For the ...

Science.gov (United States)

... Accession Number : ADD135317. Title : Workability and Heat Treatment Characteristics of Beta Titanium Alloy, Ti-15V-3Cr-3Sn-3Al,. ...

International Nuclear Information System (INIS)

Titanium base 'alpha'-alloys (Pt-7M, RK-20 and Ti-5Al-2Zr-1.5V) are considered for their behaviour under neutron irradiation. The role of alloying elements in radiation hardening is discussed depending of neutron fluence and irradiation temperature. For PK-20 alloy three stages of change in mechanical properties are revealed which are following: incubation period and weak hardening, intense radiation hardening, radiation hardening attenuation. Irradiation temperature rise results in an increase of incubation period and threshold neutron fluence. A special attention is paid to hydrogen absorption in #alpha#-titanium alloys under irradiation. It is concluded that titanium base 'alpha'-alloys are serviceable as structural materials in nuclear plants with allowance made for peculiar features of their radiation behaviour. 4 refs.; 7 figs.; 1 tab.

Science.gov (United States)

... information about, utilized, or discussed these subjects: basic topics: overview materials and material types: ti-6al-4v, ti1100, ti17 , ti6242, imi 550 ...

International Nuclear Information System (INIS)

1972. United States Narayanan, GH Archbold, TF Univ. of California Press.;

Science.gov (United States)

... silicon oxide (BSO), bismuth germanium oxide (BGO), and bismuth titanium oxide (BTO). These crystals are electro-optic, optically active, ...

International Nuclear Information System (INIS)

(Feb 1972). United States Nelson, HG Williams, DP Stein, JE v. 3(2)

Science.gov (United States)

Procedures for a New High-Strength, Beta Titanium Alloy having. Superior Formability, " Technical Report AFML-TR-69-171, Air ...

Energy Technology Data Exchange (ETDEWEB)

Austenitic stainless steels (304-type) have been implanted with nitrogen ions in order to investigate the effects of implanted nitrogen on their electrochemical behaviour and on the nature of the passive film formed on the steels in acid (0.5M H{sub 2}SO{sub 4}). Alloys with two nitrogen doses have been prepared (2.5x10{sup 16} and 2x10{sup 17} N atoms/cm{sup 2}). The implanted alloys have been characterized by {sup 15}N-NRA (nuclear reaction analysis) and XPS (X-ray photoelectron spectroscopy). Alloy surfaces with well-defined N concentrations were prepared, prior to the electrochemical measurements, by argon-ion sputtering of the implanted material for a fixed time in order to reach a well-defined point on the nitrogen depth profile. The samples were then transferred without exposure to air to an electrochemical cell mounted in an inert gas glove box. The implanted nitrogen ...

International Nuclear Information System (INIS)

As an unconventional surface alloying process, ion implantation has been utilized to improve the active-passive behavior and the pitting resistance of martensitic M50 engineering alloy. In a field simulation study, Cr-implantation only at 150 kev to a fluence of 2 x 10"1"7 ions/cm"2 prevented pitting. The best pitting resistance of the steel was obtained with multiple implantations of Cr and Mo. The intermixing effect of high fluence P-implantation into 304 stainless produced an amorphous surface alloy. The removal of the grain boundaries and the uniformity of the resulting structure had a great influence on corrosion properties. REED analysis indicated that the anodic passive films formed on P-implanted 304 stainless steel at 250 mV (SCE) in 0.5M H_2SO_4 was amorphous. Phosphorus and boron were implanted into 316 stainless steel to study the passivity of 316 ...

International Nuclear Information System (INIS)

Boron is implanted in crystalline silicon through oxide layers with different thicknesses. The implantation is carried out at various doses and energies of interest in ultra large scale integration (ULSI) application. Rapid thermal annealings (RTA) are used to obtain shallow junctions and electrical activation of the B atoms. However, transient enhanced diffusion induced by implantation damage can be observed. The boron concentration profiles before and after annealing are obtained with secondary ion mass spectrometry (SIMS). It is found that the diffusion transient in the tail region of the boron profile increases with decreasing oxide thickness. Even more, if the implantation damage concerns mostly the oxide, i.e. when the concentration peak is located in this oxide, the oxygen knocked into the silicon substrate could play this way an important role in restricting the boron diffusion, which is good to ...

Energy Technology Data Exchange (ETDEWEB)

The diffusion of Sb and B markers has been studied in vacancy supersaturations produced by MeV Si implantation in float zone (FZ) silicon and bonded etch-back silicon-on-insulator (BESOI) substrates. MeV Si implantation produces a vacancy supersaturated near-surface region and an interstitial-rich region at the projected ion range. Transient enhanced diffusion (TED) of Sb in the near surface layer was observed as a result of a 2 MeV Si{sup +}, 1 {times} 10{sup 16}/cm{sup 2}, implant. A 4{times} larger TED of Sb was observed in BESOI than in FZ silicon, demonstrating that the vacancy supersaturation persists longer in BESOI than in FZ. B markers in samples with MeV Si implant showed a factor of 10{times} smaller diffusion relative to markers without the MeV Si{sup +} implant. This data demonstrates that a 2 MeV Si{sup +} implant injects vacancies into the near ...

Energy Technology Data Exchange (ETDEWEB)

Aqueous solutions (mixed waste) generated from various LLNL operations, such as debris washing, sample preparation and analysis, and equipment maintenance and cleanout, were combined for storage in the B695 tank farm. Prior to combination the individual waste streams had different codes depending on the particular generating process and waste characteristics. The largest streams were CWC 132, 791, 134, 792. Several smaller waste streams were also included. This combined waste stream was treated at LLNL's waste treatment facility using a vacuum filtration and cool vapor evaporation process in preparation for discharge to sanitary sewer. Prior to discharge, the treated waste stream was sampled and the results were reviewed by LLNL's water monitoring specialists. The treated solution was discharged following confirmation that it met the discharge criteria. A major source, accounting for 50% for this waste stream, is metal machining, cutting and ...

International Nuclear Information System (INIS)

Implanted B and P dopants in Si exhibit transient enhanced diffusion (TED) during annealing which arises from the excess interstitials generated by the implant. In order to study the mechanisms of TED, transmission electron microscopy measurements of implantation damage were combined with B diffusion experiments using doping marker structures grown by molecular-beam epitaxy (MBE). Damage from nonamorphizing Si implants at doses ranging from 5x10"1"2 to 1x10"1"4/cm"2 evolves into a distribution of #left brace#311#right brace# interstitial agglomerates during the initial annealing stages at 670 endash 815 degree C. The excess interstitial concentration contained in these defects roughly equals the implanted ion dose, an observation that is corroborated by atomistic Monte Carlo simulations of implantation and annealing processes. The injection of interstitials from ...

International Nuclear Information System (INIS)

The influence of heat treatment on the structure, mechanical properties and fracture peculiarities of high-strength (#alpha#+#beta#)-titanium alloy VT22 has been studied. It is ascertained that thermal cycling and subsequent high-temperature aging permit to reduce considerably crack growth rate. Thermal cycling is realized in the following mode: heating in #beta#-region, cooling and allowance in (#alpha#+#beta#)-region, heating in #beta#-region.

International Nuclear Information System (INIS)

VT6 titanium alloy long-range fibers have been extracted from the suspended melt drop with the following high-rate solidification. Formation of the structure of fibrous porous material prepared from these fibers has been studied. 7 refs.; 5 figs.; 2 tabs.

International Nuclear Information System (INIS)

The influence of structure on mechanical properties in the course of tensile tests in a wide range of temperatures was studied, using the VT16 structure thermally strengthened (alpha+beta)-titanium alloy by way of example. It is ascertained that transition from ductile to brittle fracture at the temperature of -196 deg C is observed only in coarse-grain alloy having alpha-eldging of beta grains.

International Nuclear Information System (INIS)

Effect of cooling rates within the wide range (0.003-45 grad/s) on the complex of mechanical properties of (#alpha#-#beta#)-titanium alloy VT3-1 is studied in the process of heat treatment. Cooling conditions of semifinished product made of this alloy with a different structure providing optimum combination of strength, ductility fracture toughness, heat resistance, and endurance are determined.

Science.gov (United States)

The effects of fluoride on the corrosion behavior of Titanium Grade 7 (0.12-0.25% Pd) have been investigated. Up to 0.1 mol/L fluoride was added to the NaCl brines at 95oC, and three pH values of 4, 8, and 11 were selected for studying pH dependence of fl...

Energy Technology Data Exchange (ETDEWEB)

An energy dispersive x-ray fluorescence technique was used for the determination of Titanium (Ti) and Zirconium (Zr) in red mud by using a standard addition method. An annular {sup 241}Am source is employed for excitation of K shells of elements. 13 refs., 2 figs., 1 tab.

Science.gov (United States)

The papers contained in this volume provide an overview of recent theoretical and experimental research related to the fracture toughness and fatigue crack growth characteristics of titanium alloys. Topics discussed include room temperature fatigue crack propagation in beta-titanium alloys, fatigue crack growth rate acceleration in alpha+beta Ti alloys, influence of transformed beta microstructures on fatigue crack growth rates in Ti-6Al-4V, and the role of inclusion and pore content on the fracture toughness of powder processed blended elemental Ti-10V-2Fe-3Al. Papers are also presented on fatigue crack growth measurements in an alpha-beta titanium alloy, the effects of thermal processing variation on the properties of Ti-6Al-4V, and the effect of microstructure on ductility and fracture toughness of alpha+beta titanium alloys.

Energy Technology Data Exchange (ETDEWEB)

Implanted B and P dopants in Si exhibit transient enhanced diffusion (TED) during initial annealing which arises from the excess interstitials generated by the implant. In order to study the mechanisms of TED, the authors have used B doping marker layers in Si to probe the injection of interstitials from near-surface, non-amorphizing Si implants during annealing. The in-diffusion of interstitials is limited by trapping at impurities and has an activation energy of {approximately}3.5 eV. Substitutional C is the dominant trapping center with a binding energy of 2--2.5 eV. The high interstitial supersaturation adjacent to the implant damage drives substitutional B into metastable clusters at concentrations below the B solid solubility limit. Transmission electron microscopy shows that the interstitials driving TED are emitted from {l_brace}311{r_brace} defect clusters in the damage region at a rate which ...

Energy Technology Data Exchange (ETDEWEB)

Transient enhanced diffusion (TED) of boron in silica after low energy boron implantation and annealing was investigated using boron-doping superlattices (DSLs) grown by low temperature molecular beam epitaxy. Boron ions were implanted at 5, 10, 20, and 40 keV at a constant dose of 2{times}10{sup 14}/cm{sup 2}. Subsequent annealing was performed at 750{degree}C for times of 3 min, 15 min, and 2 h in a nitrogen ambient. The broadening of the boron spikes was measured by secondary ion mass spectroscopy and simulated. Boron diffusivity enhancement was quantified as a function of implant energy. Transmission electron microscopy results show that {l_angle}311{r_angle} defects are only seen for implant energies {ge}10 keV at this dose and that the density increases with energy. DSL studies indicate the point defect concentration in the background decays much slower when {l_angle}311{r_angle} defects are ...

Energy Technology Data Exchange (ETDEWEB)

The reduction of transient enhanced diffusion (TED) with reduced implantation energy has been investigated and quantified. A fixed dose of 1{times}10{sup 14} cm{sup {minus}2} Si{sup +} was implanted at energies ranging from 0.5 to 20 keV into boron doping superlattices and enhanced diffusion of the buried boron marker layers was measured for anneals at 810, 950, and 1050{degree}C. A linearly decreasing dependence of diffusivity enhancement on decreasing Si{sup +} ion range is observed at all temperatures, extrapolating to {approximately}1 for 0 keV. This is consistent with our expectation that at zero implantation energy there would be no excess interstitials from the implantation and hence no TED. Monte Carlo modeling and continuum simulations are used to fit the experimental data. The results are consistent with a surface recombination length for interstitials of {lt}10 nm. The data presented here ...

Energy Technology Data Exchange (ETDEWEB)

Excellent silicided shallow p{sup +}n junctions have been successfully achieved by the implantation of BF{sub 2}{sup +} ions into thin Pd{sub 2}Si films on Si substrates to a dose of 5 {times} 10{sup 15} cm{sup {minus}2} and subsequent low temperature (even at 550 C) furnace annealing. The formed junctions have been characterized for respective implantation conditions. In this experiment, the implant energy is the key role in obtaining a low leakage diode. Reverse current density of about 3 nA/cm{sup 2} and an ideality factor of about 1.05 can be attained by the implantation of BF{sub 2}{sup +} ions at 80 keV and subsequent annealing at 550 C. The junction depth is about 0.09 {mu}m, measured by the spread resistance method. As compared with the results of unimplanted specimens, the implantation of BF{sub 2}{sup +} ions into a thin Pd{sub 2}Si layer can stabilize the silicide film ...

International Nuclear Information System (INIS)

An attempt was made to minimize the channeling tail by implantation along a random equivalent direction following a careful alignment of the target. In order to analytically determine the random equivalent directions, critical angles for channeling were mapped on a stereogram. Boron ions with energies of 17 and 45 keV are implanted along specified directions determined from the map. The depth distribution of the dopant is profiled by SIMS and the effects of water orientation upon the channeling tail are noted. Industrial common use of a 7"0 tilt is not optimum. However, implantation with the wafer tilted at 5.5 +/- 0.5"0 from the surface normal and rotated at 7.0 +/- 0.5"0 from a (100) plane shows the least channel-tail compared to implantation along other directions. Rapid thermal annealing (RTA) is a promising annealing method for shallow junction formation. Transient enhanced diffusion of ...

Energy Technology Data Exchange (ETDEWEB)

The changes in the electrical and structural properties of metal-silicide films caused by ion implantation and subsequent thermal annealing have been investigated. Epitaxial silicide films such as those of CoSi/sub 2/, NiSi/sub 2/ and Pd/sub 2/Si grown on Si(111) substrates were implanted with Ar ions and annealed in a vacuum furnace at temperatures ranging from 200 to 800/sup 0/C. Rutherford backscattering and channeling techniques and the four-point probe method were used to measure the crystalline quality and the sheet resistance of the films, respectively. It was found that the sheet resistances of CoSi/sub 2/, NiSi/sub 2/ and Pd/sub 2/Si films were increased by factors of 70, 6, and 3, respectively, by implantation to a dose of 1 x 10/sup 16/ Ar-ions/cm/sup 2/, but that they were almost restored by subsequent annealing to the values before implantation. A phase transformation from Pd/sub 2/Si to ...

Energy Technology Data Exchange (ETDEWEB)

Accurate modeling of the enhanced diffusion of boron during rapid thermal annealing has been accomplished by incorporating the effects of extended defect formation and annealing on enhanced diffusion into a multizone, semiempirical model. The multizone model divides the implant profile into three zones defining regions of different defects and diffusion enhancements. The model also contains the initial enhanced diffusion and the transient diffusion effects associated with the dissolution of defect clusters and the annealing of extended defects, respectively. The saturation time for transient-enhanced diffusion contains an exponential function of implant dose in order to model the increase in point defect generated with higher implant dose. As a result, the model accurately simulates the boron diffusion profile over a wide range of implant doses and also shows the immobile boron peak of precipitated ...

International Nuclear Information System (INIS)

The characteristics of defects induced by Si and Ga focused ion beam (FIB) implantation in n-GaAs have been investigated by means of deep-level transient spectroscopy (DLTS), C--V carrier profiling, and resistance measurements. The DLTS spectra of Si and Ga FIB implanted samples annealed at temperatures up to 500 "0C are apparently identical to one another and show three different electron traps with an activation energy between 0.25 and 0.6 eV. The resistance increases by more than five orders of magnitude by Si and Ga FIB implantation due to the induced defects. However, it is restored to initial values after annealing at 600 "0C, except for a sample of Ga implantation with a dose higher than 10"1"4 cm"2 . For annealing of induced defects, there are no intrinsic problems for FIB implantation with a dose lower than 10"1"3 cm"2.

Energy Technology Data Exchange (ETDEWEB)

The transient behavior of P diffusion in Si implanted with As or Ge above the amorphizing threshold has been investigated. Annealing at 720{degree}C after Ge implantation induces extensive P segregation into the extended defect layer formed by implantation damage. This segregation is attributed to P trapping to end-of-range {l_brace}311{r_brace} defects and dislocation loops. For As implantation, P segregation was also observed only after 1 min annealing. However, in contrast to the Ge implantation, in the As-implanted samples, significant P depletion occurs in the As-tail region after further annealing. Nonequilibrium simulation that takes into account both Fermi-level and electric field effects shows the P depletion during transient enhanced diffusion. Furthermore, simulation results based on the coexistence of neutral and positively charged ...

International Nuclear Information System (INIS)

The author investigates the diffusion and damage-annealing characteristics as a result of boron implantation through a surface oxide into the silicon, a process that is commonly realized in the fabrication of p-n junctions. Defect structures were examined using plan-view and cross-section transmission-electron microscopies. It is shown that recoil-implanted oxygen plays a critical role in determining the above annealing characteristics. For instance, transient-enhanced diffusion of boron, as is widely observed for boron-implanted silicon, does not occur in the case of through-oxide implantation. The initial suppression of the defect-enhanced diffusion lasts for a limited period of time after which enhanced diffusion occurs again. The so-called incubated enhanced diffusion' is characterized as due to recoiled-oxygen precipitation-emitting point defect that enhances boron motion. The incubation time ...

International Nuclear Information System (INIS)

A unified physically based ion implantation damage model has been developed which successfully predicts both the impurity profiles and the damage profiles for a wide range of implant conditions for arsenic, phosphorus, BF_2, and boron implants into single-crystal silicon. In addition, the amorphous layer thicknesses predicted by this new damage model are also in excellent agreement with experimental measurements. This damage model is based on the physics of point defects in silicon, and explicitly simulates the defect production, diffusion, and their interactions which include interstitial-vacancy recombination, clustering of same type of defects, defect-impurity complex formation, emission of mobile defects from clusters, and surface effects for the first time. New computationally efficient algorithms have been developed to overcome the barrier of the excessive computational requirements. In addition, the new model has ...

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More efficient and safe production machines are required for sod peat production. The efficiency and durability of machines is especially important in contract work. Two sod peat harvester types, Pala-14 and Turve-Unsa, were tested by the forest department of the Work Efficiency Associationin summer 1986. Sod peat was collected with these machines at three sod peat production sites. The yield of the Pala-14 harvester was 121 m/sup 3//h for harvesting time, and 56 m/sup 3//h for worksite time, and that of Turve-Unsa was 108 m/sup 3//h and 55 m/sup 3//h, respectively.

CERN Document Server

The whole computer hardware industry embraced multicores. For these machines, the extreme optimisation of sequential algorithms is no longer sufficient to squeeze the real machine power, which can be only exploited via thread-level parallelism. Decision tree algorithms exhibit natural concurrency that makes them suitable to be parallelised. This paper presents an approach for easy-yet-efficient porting of an implementation of the C4.5 algorithm on multicores. The parallel porting requires minimal changes to the original sequential code, and it is able to exploit up to 7X speedup on an Intel dual-quad core machine.

International Nuclear Information System (INIS)

Surface quality is one of the most important criteria for establishing the optimum cutting parameters needed to perform a machining process. Usually, the evaluation of the degree of the surface finishing requires to apply metrological techniques which involve times out in the production. As a consequence of this, a loss in both the economy of the process and the fiability of the tests reproducibility can be produced. In this work a relation between cutting force and surface roughness has been studied for the turning process of an Al-Cu alloy. From this relation, the surface quality of the machined samples can be evaluated by using the cutting forces values acquired during the cutting process. (Author) 8 refs.

International Nuclear Information System (INIS)

The penetration depth and concentration distribution for vanadium ions with low energy implanted into the dry peanut seeds is determined by scanning electron microscope and X-ray energy dispersion spectrometer. The results show that the depth-concentration distribution is a Gaussian distribution with a long tail and the maximum penetration depth is about 13.6 #mu#m for V"+ with 200 keV in cotyledon of the peanut. The experimental result of the implanted V"+ range in the peanut seeds is compared with the calculating value of the TRIM95

International Nuclear Information System (INIS)

This paper describes Z-contrast scanning transmission electron microscopy used to study the connection between dopant precipitation and phase transformation in high dose In"+ and Sb"+ implanted Si. In the case of In, the observations confirm a heterogeneous nucleation model. Images of the precursor precipitates give the first measurement of the diffusion coefficient in amorphous Si, with an enhancement of 10"7 over tracer crystalline values. With Sb"+ implants enhanced homogeneous nucleation is observed. The connection between these results and the transient enhanced diffusion observed in crystallized Si is discussed.

International Nuclear Information System (INIS)

An annealing with the nanosecond laser light pulse is applied for crystal lattice reconstruction of a disturbed near-surface layer, which was created in semiconductor material as a result of the implantation process. Radiation with energy density higher than the threshold value causes the melting of the surface layer and than the epitaxial recrystallization from the melt on a different substrate. Structural changes occurring in the Ge implanted Si crystals after annealing with different energy densities are investigated by means of the cross-section high-resolution transmission electron microscopy. (author)

International Nuclear Information System (INIS)

It has been observed that dislocation loops form and grow during annealing of silicon wafers implanted at doses above the amorphization threshold. Dislocation loops can act to store interstitials for prolonged periods of anneals, sustaining an interstitial super-saturation and thus causing substantial transient enhanced diffusion (TED). The authors have developed a comprehensive model which, in combination with a model and parameters for #left brace#311#right brace# defects from previous work, accounts for the formation and evolution of dislocation loops during ion implant annealing, as well as giving the correct TED behavior.

International Nuclear Information System (INIS)

For the purpose of optimizing the process of co-implantation of MeV Si ions to reduce boron transient enhanced diffusion and boron-enhanced diffusion in Si, multiple MeV implantations and annealing at different temperatures have been performed. A slight improvement on the suppression of B diffusion is observed by adding a low temperature annealing step after the MeV implantation. No differences in B diffusion are observed when the Si doses are increased from 1 x 10"1"5 to 1 x 10"1"6 cm"-"2. This dose independent behavior is speculated to be a quasi-steady state of vacancy cluster evaporation.

Science.gov (United States)

we have a colloquium scheduled. Computing: register your machine and check our network security and visitor computer policies. For Our Information: Once arranged, please let us...

Energy Technology Data Exchange (ETDEWEB)

This paper deals with an experimental study of ultra-precision diamond cutting of magnesium alloy (AZ31). In order to investigate the machinability such as the cutting force and the surface integrity and understand the problems in a micro cutting, the experiments on the diamond cutting of magnesium alloy and pure aluminum with an ultra-precision turning machine has been carried out. The machinability of magnesium alloy was compared with that of pure aluminum and discussed. Consequently, both the thrust force component and the surface roughness obtained by cutting of magnesium alloy became larger than that of pure aluminum. It was also found that the inclusions or the defects in the work material caused to generate the scratches on the finished surface and influenced the integrity of mirror surface. (orig.)

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Officials of Saturn Machine and Welding Co., describe the company's designs of oven door, door cleaner and jamb cleaner and report performance at US coking plants.

UK PubMed Central (United Kingdom)

Privacy-preserving machine learning algorithms are crucial for the increasingly common setting in which personal data, such as medical or financial records, are analyzed. We provide general...Full Text Available

UK PubMed Central (United Kingdom)

Zirconia-based restorations are widely used in prosthetic dentistry; however, their susceptibility to hydrothermal degradation remains elusive. We hypothesized that CAD/CAM machining and subsequent...Full Text Available

Science.gov (United States)

airborne separation assistance systems (ASAS) to ... operations should be limited to the outer traffic flow ...... AGARD Meeting on Machine Intelligence in Air ...

British Library Electronic Table of Contents (United Kingdom)

Electrochemical discharge machining (ECDM) is a promising hybrid process for high-performance machining of non-conductive glass. ECDM drilling has been found to have different characteristics and material removal mechanisms in discharge regime (less than 300??m in depth) and hydrodynamic regime (more than 300??m in depth); however, these regimes are never separately modeled in existing ECDM models, which leads to large prediction error, especially at low applied voltages and high machining depths. Until now, no model is particularly designed for discharge regime, where most material is removed. In this paper, a finite element based model for ECDM drilling in discharge regime is presented. Material removal subjected to a single spark was simulated using finite element method. The drilling d...

International Nuclear Information System (INIS)

A transient-enhanced diffusion has been observed during the furnace or rapid thermal annealing of ion-implanted silicon. We have studied this transient in detail and show that, for doses of Group V dopants sufficient to amorphize the silicon, it arises from the trapping of interstitials by dopant atoms during implantation. These are retained during solidphase-epitaxial (SPE) growth, but can be released by additional thermal processing to cause the observed transient and the formation of a band of extended defects. We have measured the enhanced diffusion coefficients and the duration of the transient for Sb-implanted Si by careful furnace annealing experiments. We obtain general expressions which predict the effects of the transient during any thermal processing based on SPE growth (furnace, CW laser, or rapid thermal annealing). We show that there is no analogous mechanism of vacancy trapping by Group III elements.

Energy Technology Data Exchange (ETDEWEB)

The authors have studied in detail the transient enhanced diffusion observed during furnace or rapid-thermal-annealing of ion-implanted Si. The authors show that the effect originates in the trapping of Si atoms by dopant atoms during implantation, which are retained during solid-phase epitaxial (SPE) growth but released by subsequent annealing to cause a transient dopant precipitation or profile broadening. The interstitials condense to form a band of dislocation loops located at the peak of the dopant profile, which may be distinct from the band formed at the original amorphous/crystalline interface. The band can develop into a network and effectively getter the dopant. They discuss the conditions under which the various effects may or may not be observed, and discuss preliminary observations on As/sup +/ implanted Si. 12 references, 12 figures.

International Nuclear Information System (INIS)

The authors have studied in detail the transient enhanced diffusion observed during furnace or rapid-thermal-annealing of ion-implanted Si. The authors show that the effect originates in the trapping of Si atoms by dopant atoms during implantation, which are retained during solid-phase epitaxial (SPE) growth but released by subsequent annealing to cause a transient dopant precipitation or profile broadening. The interstitials condense to form a band of dislocation loops located at the peak of the dopant profile, which may be distinct from the band formed at the original amorphous/crystalline interface. The band can develop into a network and effectively getter the dopant. They discuss the conditions under which the various effects may or may not be observed, and discuss preliminary observations on As"+ implanted Si. 12 references, 12 figures.

UK PubMed Central (United Kingdom)

BackgroundThe routine removal of orthopaedic fixation devices after fracture healing remains an issue of debate. There are no evidence-based guidelines on this matter, and little...Full Text Available

International Nuclear Information System (INIS)

The effect of in situ photoexcitation during boron ion implantation on subsequent transient enhanced B diffusion in Si has been investigated. Photoexcitation using a mercury arc lamp was performed during B"+ implantation at 35 keV for a dose of 5x10"1"4 cm"-"2 at 177 K. A reduction in the electrical activation dip, i.e., reverse annealing effect, in the temperature range 550--700 degree C was observed. Also, the transient enhanced diffusion of B, measured using SIMS following 800 degree C, 30 min annealing, was suppressed. Both effects demonstrate that the creation of self-interstitials during the implantation process is significantly reduced. copyright 1995 American Institute of Physics.

International Nuclear Information System (INIS)

English Jul 2001 p. 143-144 China Liu Changlong Academia Sinica,

Science.gov (United States)

... Abstract : Cadmium telluride single crystals were subjected to multiple-energy boron ion implants with total doses up to 1.5 x 10 sq cm. ...

International Nuclear Information System (INIS)

As to all sinter variations the microradiographic analysis showed that about 86 to 90 % of the implant surface were enclosed split-free with newly formed bone 16 weeks post operationem. A silicat salt addition of the test variation Ap_4_0KS_1_5 and Ap_4_0KS_3_0 did not cause a negative influence on bone regeneration. On the surface of all test implants a double layer was revealed radiologically, consisting of a 30 - 40 #mu#m thick bone near X-ray impermeable area and an X-ray permeable area of maximum 120 #mu#m thickness directed to the nucleus of the implant.

British Library Electronic Table of Contents (United Kingdom)

Placement of dental implants in the interforaminal region of the edentulous mandible is considered a safe and routine surgical procedure. Hemorrhage in the floor of the mouth has been reported as a rare, potentially life-threatening complication related to the placement of implants in this region. In this case report the authors present an immediate and a delayed case of massive bleeding in the floor of the mouth after implant placement. This highly vascularized region is vulnerable and bleeding can be induced easily by instrumentation, causing a vascular trauma, usually by perforation of lingual periostium. In almost all cases the expanding hematoma formation starts during surgery. The effect of the vasoconstrictive agent in the local anesthesic combined with an injury of the lingual arte...

Energy Technology Data Exchange (ETDEWEB)

We have investigated the diffusion of Sb in Si in the presence of defects injected by high-energy implantation of Si ions at room temperature. MeV ion implantation increases the concentrations of vacancies, which induce transient-enhanced diffusion of Sb deposited in Si. We observed a significant enhancement of Sb diffusion. Secondary ions mass spectroscopy has been performed on the implanted samples before and after annealing. Rutherford-backscattering spectrometry has been used to characterize the high-energy implantation damage. By fitting diffusion profiles to a linear diffusive model, information about atomic scale diffusion of Sb, i.e. the generation rate of mobile state Sb and its mean migration length were extracted.

International Nuclear Information System (INIS)

Nuclear Reaction Analysis (NRA) with deuteron ion beams has been used to probe for ion implanted nitrogen and carbon with high sensitivity in zinc oxide and silicon single crystals. The ion implanted N was measured using 1.4 MeV deuteron ion beams and was found to be in agreement with calculated values. The limit of detection for N in ZnO is 8x1014 ions cm-2. Raman measurements of the ion implanted samples showed three additional modes at 275, 504, and 644 cm-1 compared to the un-implanted ZnO crystals. The NRA and Raman results provided information on the N concentration, depth distribution, and structural changes that occur in dependence on the nitrogen ion fluences. The deuterium induced 12C(d,p)13C reaction was used to measure the carbon impurity/dose in ion implanted silicon. It was found that the use of a large cold shield (liquid nitrogen trap) in the ion ...

International Nuclear Information System (INIS)

Nowadays, diamond and the nitrogen-vacancy (NV) colour centres constitute the best solid-state system in view of quantum-computing applications. It has also been shown recently that single NV centres could be used as nanoscale magnetic sensors. Such applications require the creation of single NV centres with very high resolution and with a high efficiency. The nano-implanter at the university of Bochum provides low energy nitrogen ions which can be implanted through a hole pierced in the tip of an atomic force microscope. Ultrapure diamond samples have been implanted with spot sizes of 50nm and less. Stimulated Emission Depletion (STED) microscopy has been used to characterise and resolve the implanted spots.

KoreaScience (Korea)

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International Nuclear Information System (INIS)

For obtaining radiation less damagable laser mirrors, a preliminary optimization of film fabrication suitable for the analysis of laser damage mechanism has been done as the first step. Here, the optimization requires not only the stable fabrication process but also the ideal film structure i.e., the amorphous and smooth film structure simultaneously, eliminating latently unwanted secondary effects such as light scattering during laser damage test. For this purpose, we adopted the ion assisted deposition (IAD) method and modified the deposition conditions for titanium and tantalum oxide films, both of which compose typical high index layers, and where SiO_2 layers are also chosen as low index layers because of their amorphous and smooth nature, in alternative multilayer laser mirrors. Surface and cross sectional film structures and film crystallinity are compared and characterized, using a high resolution SEM and a x-ray diffractometer, respectively. The ...

British Library Electronic Table of Contents (United Kingdom)

Fluoroalkyl end-capped vinyltrimethoxysilane oligomer suffered the sol-gel reaction under alkaline conditions in the presence of titanium oxide nanoparticles in tetrahydrofuran to afford the corresponding fluorinated oligomer/titanium oxide nanocomposites[RF-(VM-SiO2)n-RF/TiO2] in excellent to moderate isolated yields. These fluorinated composites thus obtained were nanometer size-controlled fine particles, and exhibited good dispersibility and stability in traditional organic solvents except for water. These fluorinated nanocomposites were applied to the surface modification of glass to exhibit not only a completely superhydrophobic characteristic (a water contact angle: 180degree) with a non-wetting property against water droplets but also a good oleophobicity imparted by fluoroalkyl seg...

International Nuclear Information System (INIS)

A thermodynamic analysis of the behaviour of Alloy 800 in helium based atmospheres relevant to the High Temperature Gas Cooled Reactor indicates that, depending upon the precise gas composition, oxidation and carburisation, or carburisation alone may be expected. The prime influence appears to be the moisture level. The morphology and structure of the reaction products are discussed. It is shown that the 'reactive' elements chromium, manganese, titanium and silicon are concentrated in the oxide scale which is normally duplex in structure. Aluminium oxide is formed at grain boundaries and in an internal oxidation zone together with titanium and sometimes silicon. In carburising conditions, mixed titanium-chromium carbides are formed. When this occurs, intergranular penetration is maximised. Weight gain data are assessed and briefly described and a tentative model for the mechanism of corrosion of Alloy 800 in HTR helium is ...

Energy Technology Data Exchange (ETDEWEB)

Titanium oxides were grown anodically to selected final potentials on grade II polycrystalline titanium under different anodization rates. XPS and RBS results show that the oxide consists of primarily TiO2 with a non-stoichiometric oxide/metal interface, with the slower growth rate associated with a thicker layer at the interface. Characterization using TEM reveals that the structure of the oxide evolves from a primarily amorphous phase to islands of crystallites in an amorphous matrix, to an entirely crystalline phase by increasing the polarization potential. Slower growth rates tend to remain crystalline at higher potentials. The mechanical strength of oxide films extracted from load-depth data by nanoindentation varies dramatically for oxide films grown by different rates at 9.4 V, and to a lesser extent at lower potentials. The variation of film strength is associated with both compositional and structural characteristics.

Energy Technology Data Exchange (ETDEWEB)

An inorganic particulate adsorbent of a titania-alumina is described for treating a superheated water containing radioactive materials such as cobalt ions, which is free from release of corrosive impruities, and which has a high adsorption capacity of radioactive materials and a high mechanical strength is prepared by hydrolyzing a titanium alkoxide and an aluminum alkoxide, thereby forming a hydrous titanium oxide and a hydrous aluminum oxide, respectively; precalcining the hydrous titanium oxide and aluminum oxide, mixing and molding the resulting titania and alumina into a particulate mixture thereof having a titania mole fraction of 0.2 to 0.9, and calcining the particulate mixture at 500/sup 0/-700/sup 0/C. This absorbent is effectively used in treat boiling water-type nuclear reactor core-circulating water to remove radioactive substances therefrom.

Energy Technology Data Exchange (ETDEWEB)

Titanium diboride was heated to high temperatures using microwaves. The highest temperature obtained was 2245/degree/C. Unfortunately, oxidation was a problem, especially at the higher temperatures, although an argon flush and a carbon getter were used. To completely stop oxidation, the oxygen potential must be below 10/sup /minus/18/ atmospheres. Using an argon flush and a carbon getter, titanium diboride was successfully densified to 82% of theoretical without measurable oxidation by heating with microwaves to 1860/degree/C. Density actually decreased upon reaching temperatures above 1860/degree/C due to void formation adjacent to the surface. Void formation is thought to be due to the formation of B/sub 2/O/sub 3/(g) which evolves rapidly above 1860/degree/C because of the loss of a TiO/sub 2/ protective film which melts at this temperature. 9 refs., 12 figs., 2 tabs.

Energy Technology Data Exchange (ETDEWEB)

A LLX procedure for carrier-free separation of the radioisotopes, {sup 47}Sc, {sup 48}V and {sup 48},{sup 49},{sup 51}Cr, the 40 MeV {alpha}-particle activation products of titanium has been developed. Sequential separations of the radionuclides produced in the titanium matrix through the nuclear reactions ({alpha}, {alpha}p{chi}n), ({alpha}, p{chi}n) and {alpha}, ({chi}n) have been performed through LLX from aqueous H{sub 2}SO{sub 4} and HClO{sub 4} acid media using the liquid cation exchanger, HDEHP, as an extractant. Purity of the carrier-free radiotracers at different stages of their separations has been verified by {gamma}-ray spectrometry. (author).

International Nuclear Information System (INIS)

A study was made into microstructure and texture of cold rolled titanium alloy VT-35 with various hydrogen content aimed to reveal hydrogen influence on the mechanism of cold plastic deformation by rolling. Experiments were carried out using sheets 1.2 mm thick hydrogenated up to hydrogen concentrations from 0.06 to 0.554 mass. %. All specimens constituted a single-phase FCC #beta#-solid solution. It is shown that small hydrogen additions have a plasticizing effect on #beta#-titanium alloys in their cold rolling. The character of texture is dependent on hydrogen concentration and determined by deformation mechanism. 6 refs.; 5 figs.

Energy Technology Data Exchange (ETDEWEB)

TiB{sub 2} appears to be a promising material for the wear protection in various tribological systems, e.g. the diecasting of Al. This study focuses on the development of titanium boride coatings deposited by PACVD, a deposition method which is most suitable for the coating of substrates with complex shapes. All layers analysed are very smooth and exhibit a quasi-amorphous fracture surface. XRD and TEM analysis indicate a nanocrystalline structure with grain sizes in the order of 2 nm. The diffraction patterns can well be correlated to titanium diboride. WDS reveals an over stoichiometric B/Ti ratio. The layer hardness reaches the value of 33 GPa and the critical load in scratch tests rises to 35 N. Neither 100Cr6 nor Al as a counterpart in pin-on-disk tests leads to wear of the coating. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The production method of the elastic composite containing ferrous particles and titanium barium particles dispersed in the porous silicone matrix is described in this article. Since it contains ferrous and titanium barium particles, this composite shows magnetorheological and also electrorheological properties. The electrostriction of composite samples in the electric field with maximal intensity 1.5x10{sup 6} V/m was investigated. The magnetostriction in the magnetic field with maximal induction 1 T was also investigated. It was found that samples elongate with increased electric field intensity, and the magnetic field induction was detected. By increasing the samples' elongation with increase of ferrous particles, titanium barium particles and pores number were also detected. In the investigated division of the electric and magnetic field the elongation changed in a linear way. The maximal elongation achieved was ...

International Nuclear Information System (INIS)

With the deposition of PVD hard coatings on the tools applied in machining operations it is possible to achieve significant improvements in the performance and quality of the machining processes. Depending on the machined material and the operating principle, e.g. turning, milling or drilling, not only different machining parameters but also different coating materials are necessary. In interrupted cut machining of tempered steel, for example, the life time of Ti-C-N coated inserts is several times greater than the Ti-C-N coated ones. This is a result of the favourable thermophysical and tribological properties of Ti-N-C. The potential for tool protection by CrN coatings is a result of the high ductility and low internal stress of this coating materials. CrN films can be deposited with greater film thickness, still maintaining very good adhesion. This paper presents the development ...

International Nuclear Information System (INIS)

The necessity of the electron beam machine characterization via dose measurement is discussed. It includes a measurement of comprehensive dose distribution (at known X and Z axis) for verification of the machine performance. The acquired data were then used to develop the irradiation parameters such as energy, current, distance, conveyor speed, exposure rate and depth inside product to be irradiated. These parameters will be used as a guide for the routine irradiations. (Author)

Energy Technology Data Exchange (ETDEWEB)

A mathematical model of the multi machine electric power system to analyse its dynamics has been worked out. The effectivity of the power system stabilizer developed in the one machine system has been tested by means of this model. The influence of the arrangement of the stabilizers on the stability of the electric power system has also been investigated. High damping of electromechanical transient processes has been achieved. 7 refs., 1 tab., 5 figs.

Science.gov (United States)

An analysis of the diagnosis of loading and service dependability of a rail-mounted excavator used in surface lignite mining is described. Wheel power vibrations in electric motor bearings and electric motor input bearings to the gearbox were measured in situ, in horizontal, vertical, and axial directions. The data were analyzed using a mathematical relationship. The results are presented in a loading diagram that shows the deterioration and the acceptable lower bound of machine conditions over time. Work is continuing. 5 refs., 1 fig.

International Nuclear Information System (INIS)

An outline of the instrumentation and control systems associated with fuelling machines is given. The control systems such as hydraulic system, oil hydraulic system, electric control system and the remote control systems have been discussed in detail. The difference between RAPP and MAPP fuel handling control systems has been explained. A computer based system for the Narora fuel handling control system is also discussed. (S.K.K.).

International Nuclear Information System (INIS)

Transient enhanced diffusion (TED) from implantation of 5keVB_1_0H_1_4 and 0.5 keV B ions has been quantified and compared for nominal boron doses of 10"1"4 and 10"1"5cm"-"2. Boron diffusivity during annealing was extracted from secondary ion mass spectroscopy depth profiles of diffused marker layers in boron doping-superlattices and the actual implanted B dose was independently measured by nuclear reaction analysis. Comparable enhancements were observed from both ions. Transmission electron microscopy analysis revealed that both boron- and decaborane-implanted samples were amorphized at a nominal 10"1"5cm"-"2B dose. A comparison with data from low energy Si implants revealed a similar dependence of diffusivity enhancement on implant dose. These findings are consistent with the understanding that TED is caused by the interstitial supersaturation resulting from a number of excess ...

UK PubMed Central (United Kingdom)

Background and ObjectivesClopidogrel resistance or low-responsiveness may be associated with recurrent atherothrombotic events after drug-eluting stent (DES) implantation. We prospectively...Full Text Available

International Nuclear Information System (INIS)

Type 304 stainless steel (SS) specimens sensitised at 873 K and 973 K for 1, 10 and 100 hours respectively were ion implanted using a 150 keV accelerator at an energy of 70 keV in two different doses of nitrogen namely 1 x 10"1"6 to 1 x 10"1"7 ions/cm"2. Ion implantation at 1 x 10"1"6 ions/cm"2 did not show any improvement in pitting resistance, however, the specimens implanted at 1 x 10"1"7 ions/cm"2 showed significant increase in pitting corrosion resistance when potentiodynamic anodic polarisation studies were carried out in acidic chloride medium. For specimens aged at 873 K, nitrogen ion implantation at 1 x 10"1"6 ions/cm"2 increased the intergranular corrosion susceptibility compared to that of unimplanted specimens. However, at the dose of 1 x 10"1"7 ions/cm"2, insignificant IGC attack was noticed. The IGC resistance increased with increase in the dose for all the specimens aged at 973 K, and the ...

International Nuclear Information System (INIS)

We have demonstrated that optical images can be stored in transparent lead-lanthanum-zirconate-titanate (PLZT) ceramics by exposure to near-UV light with photon energies greater than the band gap energy of approx. equal to 3.35 eV. The image storage process relies on optically induced changes in the switching properties of ferroelectric domains (photoferroelectric effect). Stored images are nonvolatile but can be erased by uniform UV illumination and simultaneous application of an electric field. Although high quality images, with contrast variations of >= 100:1 and spatial resolution of approx. equal to 10 #mu#m, can be stored using the photoferroelectric effect, relatively high exposure energies (approx. equal to 100 mJ/cm"2) are required to store these images. This large exposure energy severely limits the range of possible applications of nonvolatile image storage in PLZT ceramics. We have recently found from studies of H, He and Ar implanted PLZT that the ...

Science.gov (United States)

The formation and properties of Pd{sub 2}Si formed by focused ion beam implantation of Pd ions into Si is presented in this thesis. An extensive microstructural study using transmission electron microscopy was undertaken and the as-implanted as well as annealed microstructure is shown. Results of other analysis techniques such as Rutherford back scattering and secondary ion mass spectrometry etc. are also presented. Kinetic information on the growth of Pd{sub 2}Si obtained by both microstructural and resistance measurements indicates that the activation energy for growth of the silicide is around 0.36 to 0.39 eV. This can be compared with the normally reported value of 1.5 eV for Pd{sub 2}Si formed by annealing thin film Pd on Si. The growth of the silicide was found to follow t{sup 1/2} kinetics. Microstructural observation of the as-implanted samples showed extensive in-situ formation of Pd{sub 2}Di and also surprisingly ...

International Nuclear Information System (INIS)

Decaborane (B_1_0H_1_4) cluster ions were implanted into n-Si(100) substrates to fabricate shallow p"+/n junctions. Implant energies of 2 keV, 5 keV, and 20 keV, equivalent to implant energies of the monomer boron ion of 174 eV, 435 eV, and 1.74 keV, respectively, were used at dosages of 1 X 10"1"2 /cm"2 and 1 X 10"1"3 /cm"2. The implanted samples were then subjected to activation annealing at 800 .deg. C, 900 .deg. C, and 1000 .deg. C for 10 s. By using secondary ion mass spectrometry (SIMS) depth profiles, we determined that the depth of the shallow junction (D_s) at a dosage of 1 X 10"1"3 /cm"2 was in the range 12 nm - 45 nm after annealing at 1000 .deg. C. D_s and transient enhanced diffusion (TED) were greatly reduced at implant energies lower than 5 keV, but thermal diffusion (TD) smoothly decreased. In particular, TED was suppressed in the p"+/n junction ...

Energy Technology Data Exchange (ETDEWEB)

The intent and purpose of this work was to investigate and demonstrate cooperative behavior among a group of mobile robot machines. The specific goal of this work was to build a small swarm of identical machines and control them in such a way as to show a coordinated movement of the group in a flocking manner, similar to that observed in nature. Control of the swarm`s individual members and its overall configuration is available to the human user via a graphic man-machine interface running on a base station control computer. Any robot may be designated as the nominal leader through the interface tool, which then may be commanded to proceed to a particular geographic destination. The remainder of the flock follows the leader by maintaining their relative positions in formation, as specified by the human controller through the interface. The formation`s configuration can be altered manually through an interactive ...

International Nuclear Information System (INIS)

In this paper, we show that boron transient enhanced diffusion can be reduced to different extents by varying the distribution of nitrogen atoms in the junction. This is attributed to the relative location of nitrogen atoms with respect to boron profile and end-of-range defect band, affecting the interactions between dopants and defects upon annealing. In addition, variations in boron dopant activation and deactivation are also observed. Similar to fluorine co-implantation, it is proposed that nitrogen atoms react with vacancy point defects to form nitrogen-vacancy clusters that will trap the interstitials emitted from end-of-range defects. However, we report that the interstitial sink efficiency of nitrogen atoms is not as good as the co-implanted carbon atoms, which is noticed from the dopant deactivation curves. In terms of extended defect evolution, the results clearly indicate that end-of-range defects can be stabilized by choosing the ...

International Nuclear Information System (INIS)

High-dose ion implantation followed by solid-phase-epitaxial (SPE) growth is now a well-established technique for the production of supersaturated silicon alloys. However, these alloys also contain a high supersaturation of silicon interstitials, which give rise to transient, greatly enhanced dopant diffusion with subsequent heating. In this contribution, the authors present a study of a series of Si-Sb alloys of various concentrations which were made by Sb implantation under various conditions to deduce the origin of the observed transient diffusion. A multiple implant scheme was employed to produce samples with an approximately uniform dopant concentration from 40 to 150 nm in depth, but with the amorphous layer extending to a depth of 380 nm. By scaling the implant doses, alloys with different concentrations in the uniform region were produced, allowing an accurate measure of diffusion coefficients ...

International Nuclear Information System (INIS)

The use of cathode ray irradiated arterial allografts on the reconstruction of small peripheral arteries is described. The fate of irradiated arterial allografts implanted subcutaneously in rats was compared histologically with that of allografts which were fresh, frozen or stored in 70% alcohol. Follow-up studies were made of 10 dogs in which irradiated arterial allografts had been implanted in the femoral artery to be evaluated; long term patency by arteriography, gross and histologic changes of the implanted allografts, and the luminal surface of the implanted allografts by scanning electron microscopic studies. For the purpose of antigenic studies, extracts of canine arteries which had been irradiated, frozen or stored in 70% alcohol, were prepared and tested by the following immunological methods: precipitation, Ouchterlony gel diffusion, and passive cutaneous anaphylaxis. From the results obtained ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Objectives: The purpose of this study was to evaluate the osseointegration of the dental implants placed into the mandible augmented with different techniques in pigs. Material and methods: Four adult domestic pigs were used. Horizontal augmentation of the mandible was performed in animals by using vascularized femur flap (VFF), non-vascularized femur graft (NVFG) and monocortical mandibular block graft (MG). After 5 months of healing 10 dental implants were placed into each augmented site. The pigs were sacrificed after 3 months of healing. Undecalcified sections were prepared for histomorphometric analysis. Results: Mean bone-implant contact (BIC) values for implants placed into MG, NVFG and VFF were 57.38 11.97%, 76.5 7.88%, 76.53 8.15%, respectively. The BIC values of NVFG and...