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A leucemia mielóide aguda (LMA) é um grupo heterogêneo de doenças clonais do tecido hematopoiético, que é caracterizada pela proliferação anormal de células progenitoras da linhagem mielóide, resultando na produção insuficiente de células sanguíneas maduras normais, com a consequente substituição do tecido normal. O diagnóstico de LMA inicia-se a partir de uma suspeita clínica e se baseia na avaliação do sangue periférico e da medula óssea. O objetivo desta revisão é informar aos profissionais da saúde, que embora a morfologia continue sendo o fundamento para o diagnóstico, técnicas adicionais, incluindo imunofenotipagem, avaliação citogenética e estudos de genética molecular, tornaram-se essenciais e, em alguns casos específicos, são ferramentas complementares obrigatórias no auxílio ao diagnóstico.

Since its incorporation in 1998, Acsion Industries Inc. has been working with clients to develop industrial uses of electron processing for improving products and manufacturing processes. Acsion has promoted this technology for sterilizing medical devices and pharmaceuticals, for treating wood pulp in the viscose/rayon process, for reducing pathogens in food and animal feed, and for curing advanced composites for the aerospace industry. As a result of significant developments in its composite curing programs, Acsion has recently made major modifications to its facility to increase its production and R&D capabilities. These modifications are described in this paper.

A self-aligned fabrication process for small emitter contact area (2×4 μm2) GaN/AlGaN heterojunction bipolar transistor is described. The process features dielectric-spacer sidewalls, low damage dry etching, and selected-area regrowth of GaAs(C) on the base contact. The junction current–voltage (I–V) characteristics were evaluated at various stages of the process sequence and provided an excellent diagnostic for monitoring the effect of plasma processes such as chemical vapor deposition or etching. A comparison is given with large emitter-area (1.96×103 μm2) devices fabricated on the same material. The small-area devices are attractive for microwave power switching applications provided a high-yield process can be developed.

Acsion is exploiting several emerging electron beam EB applications ranging from composite curing and repair to viscose manufacturing. EB curing of composite structures offers several advantages: significantly reduced curing times; improvements in part quality and performance; reduced environmental and health concerns; improvements in material handling; and reduced overall manufacturing costs compared to thermal curing. The aerospace industry is developing EB technology in all of their market sectors, including military aviation and space products. Some specific products include cryogenic fuel tanks, improved canopy frames for jet aircraft, and the all-composite military aircraft. This paper discusses each of these opportunities.

Researchers at ACSION Industries and Oak Ridge Center for Composite Manufacturing Technology have recently achieved a major breakthrough for the composites industry by successfully developing Electron-Beam (EB) curable epoxies and EB curing cycles that reduce processing time and cost while meeting the demanding requirements of high-performance composite structures. These developments make it possible to use a large class of common epoxies to build composite parts without the need for slow, high-temperature, high-pressure curing cycles, the associated expensive fabrication tools, or the toxic chemical hardeners. The pioneering invention and development of EB-curable epoxies and the impact of these materials on EB processing of advanced composites has provided the stimulus for several companies to use these EB-curable epoxies to demonstrate numerous manufacturing advantages for EB-cured composite materials. This research has already highlighted novel composite material design concepts that are feasible only by using this technology. This paper summarizes the important aspects of EB-curable epoxies and the EB-curing process.

(1999). Porosity Measurements of Advanced Composites using Mercury Intrusion Porosimetry – A new quality tool. Materials Technology: Vol. 14, No. 3, pp. 129-132.

Advanced composites, such as carbon-fibre-reinforced epoxies, are used in the aircraft, aerospace, sporting goods, and transportation industries. Though thermal curing is the dominant industrial process for advanced composites, electron curing of similar composites containing acrylated epoxy matrices has been demonstrated by our work. The main attraction of electron processing technology over thermal technology is the advantages it offers which include ambient temperature curing, reduced curing times, reduced volatile emissions, better material handling, and reduced costs. Electron curing technology allows for the curing of many types of products, such as complex shaped, those containing different types of fibres, and up to 15 cm thick. Our work has been done principally with the AECL's 10 MeV, 1 kW electron accelerator; we have also done some comparative work with an AECL Gammacell 220. In this paper we briefly review our work on the various aspects of electron curing of advanced composites and their properties.

InP, InAlP and InGaP can be etched at rates of 0.5–0.8 μm min−1 in pure BCl3 discharges at high microwave powers (1000 W). The etch rates are strong functions of focusing magnet current, microwave power, sample temperature and to the nature of additive gases. For example, InGaP etch rates a factor of two to three faster than for BCl3 alone are obtained when small additions (25% by flow) of N2 or O2 are added to enhance dissociation of the BCl3. As microwave power is increased the surface morphology of InP is degraded, while that of InGaP improves, InAlP is relatively resistant to surface changes between 250 and 1000 W of microwave power. The sidewalls of etched features are extremely smooth and suitable for a variety of photonic devices.

Electron accelerators are being widely used in industry to process polymeric materials. Their use to cure fiber-reinforced composites is an emerging technology, based on the work done here in Canada, and in France. The advantages of electron curing include ambient temperature curing with reduced internal stress, reduced curing times, and overall cost of savings. In this paper we present a brief review of our work with emphasis on the effects of dose and dose rate, temperature rise during curing, internal stress, voids, properties of matrix resins and a comparison of the properties of electron cured and thermally cured matrices and composites.

Research to develop products and processes tor the electron curing of fibre-reinforced composites is rapidly progressing at several industrial and government laboratories, including AECL Research. Electron curing uses high-energy electrons or X-rays generated from these electrons, rather than thermal energy, to cure selected composite matrix polymers and to enhance their physical and chemical properties. Our recent programs have focussed on resin development, economics and process design. This paper summarizes the recent advances in electron curing technology.

Radiation modification of the gel content and the complex modulus of plastics was used to determine the depth-dose distribution in a solid polyethylene block irradiated with a 10 MeV electron beam, under typical radiation processing conditions. The results indicate that the accumulated charge has no significant effect on the shape of the dose profile. This suggests that, under certain circumstances, intrinsic “dosimeters” could be more appropriate than conventional thin film dosimeters placed inside the material for dose measurements in electrically non-conducting materials.

The use of carbon tetrachloride was examined as a means of suppressing deposition on the dielectric mask during the selective regrowth of III–V epitaxial layers by organometallic vapor phase epitaxy. Highly anisotropic dry etching was used to form narrow (∼1 μm wide) trenches and mesas. Reentrant mesas were formed by wet chemical etching. Under conventional growth conditions, polycrystalline GaAs was deposited over the mask adjacent to the trenches. By adding CCl4, selectivity could be greatly enhanced; however the growth rate in the trenches was significantly increased due to lateral diffusion of the reactants upon desorption from the mask thereby making acceptable control of the growth rate difficult. Addition of CCl4 during the growth of InP and AlGaAs significantly improved the selectivity in the case of growth around etched mesas.

We use electric field singularities in biased metal semiconductor microstructures to enhance the generation of terahertz (THz) radiation from semiconductors. We find that, regardless of the mechanism that is responsible for enhanced THz emission near the anode, singular electric fields near sharp anode features will enhance this emission by as much as an order of magnitude. We show scanning THz measurements of several of these structures and discuss the physical mechanism responsible for this enhanced emission. A new family of more efficient terahertz emitters based on these effects can be designed that will improve the dynamic range of THz imaging and spectroscopy systems.

Advanced composites, specifically carbon-fiber-reinforced epoxies, are used extensively for a variety of demanding structural applications, primarily because of their high strength-to-weight and stiffness-to-weight ratios, corrosion resistance, and damage tolerance characteristics. Electron beam (EB) treatment can be used to produce useful physical and/or chemical changes in plastics and composites by initiating various polymerization and crosslinking reactions. The advantages of using EB rather than thermal curing for carbon-fiber-reinforced epoxy composites include curing at ambient temperature, reduced curing times, and fewer volatiles. An EB-curable carbon fiber-acrylated epoxy composite is being developed for various applications. The tensile properties of the 14-ply EB-cured epoxy laminate were comparable with the properties of the thermally cured laminates used in the aircraft industry. Research is continuing to develop resin formulations and select coupling agents to improve the compression properties of EB-cured laminates.

Using metal organic chemical vapor deposition, we have fabricated self-organized quantum dots that emit efficiently at 1.3 μm at room temperature. They are grown on GaAs and consist of InAs covered with an InGaAs cap layer. Their density is 2×1010 cm−2 as determined by transmission electron microscopy. Room-temperature photoluminescence shows a 36 meV broad line at 1.3 μm, corresponding to the quantum-dot ground state, with excellent uniformity across the wafer. The efficiency of this emission is reduced only by a factor of 4 with respect to low temperature showing the high quality of the sample.

Iodine-129 and carbon-14 are of lesser importance than many other radionuclides in nuclear waste management because of their relatively low radiotoxicity. Their safe immobilization and disposal, however, is a significant challenge because their chemical properties are quite different from most other components of nuclear fuel waste. The authors have sought thermodynamically defensible inorganic waste forms for both of these radioisotopes. This paper discusses the stability and solubility of inorganic iodides as they relate to the selection of a waste form for iodine-129. The best candidates appear to be silver iodide (AgI), either alone or in combination with silver chloride (AgCl), and a combination of Bi 5 O 7 I and Bi 2 O 3 . Neither is completely satisfactory. The principal drawback of AgI is its relative ease of reduction. High chloride concentrations also increase the solubility of AgI, but it is insensitive to carbonate. The main disadvantage of bismuth oxyiodide is its susceptibility to displacement reactions with dissolved chloride and carbonate; also, it is unstable under strongly reducing conditions.

We describe the first results of hybrid mode locking combining both active and passive mode locking of a semiconductor laser. These functions are integrated into a monolithic device with a 1.3 μm GaInAsP gain region, an active waveguide, and a saturable absorber. The devices have low threshold currents, and exhibit hysteresis in their light/current characteristics. The long integrated waveguides allow mode locking at a repetition rate of 15 GHz without the need for an external cavity. Pulse widths as short as 1.4 ps have been demonstrated using the combined effects of active and passive mode locking.

Recently developed epoxy paste adhesives were electron beam cured and experimentally explored to determine their suitability for use in an aerospace-quality aircraft component. There were two major goals for this program. The first was to determine whether the electron beam-curable past adhesives were capable of meeting the requirements of the US Air Force T-38 supersonic jet trainer composite windshield frame. The T-38 windshield frame`s arch is currently manufactured by bonding thin stainless steel plies using an aerospace-grade thermally-cured epoxy film adhesive. The second goal was to develop the lowest cost hand layup and debulk process that could be used to produce laminated steel plies with acceptable properties. The laminate properties examined to determine adhesive suitability include laminate mechanical and physical properties at room, adhesive tack, out-time capability, and the debulk requirements needed to achieve these properties. Eighteen past adhesives and four scrim cloths were experimentally examined using this criteria. One paste adhesive was found to have suitable characteristics in each of these categories and was later chosen for the manufacture of the T-38 windshield frame. This experimental study shows that by using low-cost debulk and layup processes, the electron beam-cured past adhesive mechanical and physical properties meet the specifications of the T-38 composite windshield frame.

This is a report on work in progress on microelectrical and mechanical systems (MEMS)-based gas turbine engines, turbogenerators, and rocket engines currently under development at MIT. Fabricated in large numbers in parallel using semiconductor manufacturing techniques, these engines are based on micro-high speed rotating machinery with the same power density as that achieved in their more familiar, full-sized brethren. The micro-gas turbine is a 1 cm diameter by 3 mm thick SiC heat engine designed to produce 10-20 W of electric power or 0.050.1 Nt of thrust while consuming under 10 grams/hr of H 2 . Later versions may produce up to 100 W using hydrocarbon fuels. A liquid fuel, bi-propellant rocket motor of similar size could develop over 3 lb of thrust. The rocket motor would be complete with turbopumps and control valves on the same chip. These devices may enable new concepts in propulsion, fluid control, and por table power generation.

The volumetric mixing in anionic/nonionic, cationic/nonionic, and anionic/cationic mixed micelles was determined by examining the total surfactant apparent molar volumes (φ V,tot ) at total surfactant concentrations ( C T ) much greater than the mixture critical micelle concentration (CMC m ). The mixed surfactant systems investigated were sodium dodecyl sulfate and a polyethoxylated nonylphenol, at 0.15 M NaCl and with no added NaCl; cetyl pyridinium chloride and polyethoxylated nonylphenol, at 0.03 M NaCl; and sodium dodecyl sulfate and dodecyl pyridinium chloride, at 0.15 M NaCl. For all of the mixed surfactant systems investigated, the volumetric mixing in the mixed micelles at C T >> CMC m was ideal, even though the free energies of mixing at the onset of mixed micelle formation (as indicated by the mixture critical micelle concentrations at C T = CMC m ) exhibited strong negative deviations from ideality. Furthermore, added electrolyte was shown to have virtually no effect on the φ V,tot data (nor, consequently, the volumetric mixing) for the anionic/nonionic mixed surfactant system. The results of this study suggest that at C T >> CMC m , the electrostatic interactions do not significantly affect the molar volume of the mixed micelle. Therefore, the micelle hydrophobic core dominates the volumetric mixing in mixed micelles at C T >> CMC m .

Some published results on mode locked monolithic lasers are reviewed. Optical spectra of a typical hybrid mode-locked monolithic device for different levels of RF power and frequency are shown and discussed, as are effects of detuning the modulation frequency. Design considerations are examined. These include the length of the device, the use of hybrid mode locking, and the choice of active or passive waveguides. >

Etch rates for InP, InAlP, and InGaP can be controlled between ∼1500 A/min and ≳1 μm/min by varying the microwave power, rf power, or N2 composition in BCl3N2 discharges under electron cyclotron resonance conditions. The surface morphology of InGaP is poor at low microwave power (250 W), but becomes very smooth at high powers (1000 W). InP has exactly the opposite dependence on microwave power, while InAlP shows little change in morphology over a wide range of powers. The high ion current under electron cyclotron resonance conditions enables etching of In‐based semiconductors without the need for high sample temperatures to enhance desorption of InClX species.

The rate of sodium and potassium released from an alkali feldspar reacting with an aqueous solution varied with time. After an initial rapid exchange of alkalis for H+, dissolution rate decreased g...

The effect of a magnetic field on the light emission from squalane solutions of fluorene, pulse irradiated at the center of a large electromagnet, is described. The fluorescence intensity following pulse radiolysis was found to be 40 to 50 percent higher in an applied field of 0.3 T (3000 G) and the triplet yield showed a small decrease. The enhancement of the singlet emission is attributed to an increase in the fraction of geminate solute ion recombinations leading to excited singlet fluorene. The magnetic field effect was time dependent, being undetectable during the pulse and reaching a maximum value after about 100 ns. These observations are compared with the theory of Brocklehurst which describes the singlet to triplet conversion of geminate solute ion pairs quantitatively in terms of the electron--nuclear hyperfine interactions in the radical ions. After correction for the large in-pulse fluorescence and its decay, satisfactory agreement between experiment and theory was obtained. The results emphasize the importance of ion recombination in the generation of excited states in radiolysis and confirm the role of the electron--nuclear spin interaction in determining the ratio of singlet and triplet yields.

The effect of an applied magnetic field on the fluorescence from γ-irradiated solutions of perfluorobiphenyl and perfluoronaphthalene has been measured in various solvents. In all the solvents used (cyclohexane, squalane, isooctane) the fluorescence intensity increases with increasing field and tends towards a plateau at high fields (>0.1 T). At low fields, the fluorescence enhancement is smaller for the perfluorocarbons than for the parent hydrocarbons, due to the larger electron–nuclear hyperfine coupling and broader spread of the hyperfine levels in the radical ions of the perfluorocarbons. At high fields the fluorescence enhancement is also smaller for the perfluorocarbons than for the parent hydrocarbons, indicating a larger relative proportion of prompt (field-independent) fluorescence for the perfluorocarbons than for the parent hydrocarbons.

The capped-mesa buried-heterostructure distributed-feedback (CMBH-DFB) laser structure requires three epitaxial growths and is designed to allow good control of the width of the active layer using straightforward chemical etching techniques. The base structure, which contains the active layer, was fabricated using a variety of epitaxial techniques: liquid-phase epitaxy, hydride vapor-phase epitaxy (VPE) and metalorganic vapor-phase epitaxy (MOVPE). The final cap growth was done using hydride VPE. High yields of low-threshold high-power DFB lasers were produced from a number of wafers at emission wavelengths of 1.3 and 1.55 mu m. >

Observations are reported on the interconversion of solid α-Bi2O3, Bi12O17Cl2, BiOCl, and a daubréeite-like phase tentatively identified as Bi2O2(OH)Cl, in aqueous chloride solutions at 25 °C. Equilibrium constants, K, for these interconversions are expressed as anion activity ratios, {Cl−}/{OH−}. Experimental values of K for equilibrium between Bi2O3 and each of the chlorides are 100.56 ± 0.20 for Bi12O17Cl2, 101.5 ± 0.4 for Bi2O2(OH)Cl, and 103.13 ± 0.04 for BiOCl; the fatter two represent metastable equilibria. These equilibrium constants yielded the following estimates of Gibbs energies of formation: Bi12O17Cl2, −3141 ± 6 kJ mol−1;"Bi2O2(OH)Cl", −696 ± 4 kJ mol−1; BiOCl, −321.5 ± 1.3 kJ mol−1. Phase relationships among these solids are discussed, with reference to natural occurrence, other bismuth oxychlorides, and the stability of other basic salts of bismuth.

The decomposition of synthetic hydrocerussite, Pb 3 (OH) 2 (CO 3 ) 2 , and plumbonacrite, Pb 10 O(OH) 6 (CO 3 ) 6 , in both CO 2 and inert atmospheres, was compared using differential thermal analysis and thermogravimetry. The overall weight losses, upon decomposition to PbO, were in good agreement with calculated values. The initial dehydration steps for hydrocerussite and plumbonacrite yielded 2 PbCO 3 ·PbO, and a mixture of 2 PbCO 3 ·PbO and PbCO 3 ·PbO, respectively, consistent with the lower carbonate content of plumbonacrite than hydrocerussite. These differences do not account for discrepancies among the numerous previous reports on hydrocerussite decomposition. Rather, the decomposition route of a lead carbonate seems to be highly sensitive to the nature of its formation.

Four basic lead carbonates were prepared and identified by X-ray powder diffractometry. These were hydrocerussite (Pb3(OH)2(CO3)2), plumbonacrite (Pb10O(OH)6(CO3)6), and the two adducts MOH•2PbCO3 (M = Na, K). New diffraction data are presented for the latter two compounds; they both have primitive hexagonal lattices with two formula units per unit cell. The unit cell dimensions of the sodium and potassium compounds are a = 5.273 ± 0.002 Å, c = 13.448 ± 0.005 Å and a = 5.348 ± 0.002 Å, c = 13.990 ± 0.005 Å, respectively. Six possible space groups are discussed.Raman and infrared spectra are reported for all four compounds, and compared with those of cerussite (PbCO3); assignment of the spectral features is discussed. Vibrational spectra of the two MOH adducts indicate that they are isostructural, and that the structure contains a well-defined lead sub-lattice, consistent with the X-ray data. The spectra of hydrocerussite and plumbonacrite indicate that lead is present as oxygen-bridged polymeric moieties in these solids. The carbonate ions occupy two and three independent sites in hydrocerussite and plumbonacrite, respectively.

We have determined equilibrium conditions for each reaction in the solid interconversion sequence [Formula: see text], in aqueous carbonate solutions near 25 °C. Our data yield the following Gibbs energies of formation from the elements, ΔfG°(298.15 K): plumbonacrite, −5310 ± 31 kJ mol−1; hydrocerussite, −1705 ± 11 kJ mol−1; cerussite, −628.0 ± 3.9 kJ mol−1. Corresponding estimated values of ΔfG°(373 K) are −5120 ± 50, −1643 ± 18, and −612 ± 9 kJ mol−1, respectively. We have demonstrated the existence of a narrow stability field for plumbonacrite, and convenient small-scale preparations of hydrocerussite and plumbonacrite are described. Gibbs energy data for the solids have been combined with selected data for aqueous lead species in a detailed computation of solubility behaviour for this system at 25 °C.

Radiation processing is the utilization of ionizing radiation, usually photons or electron beams, to produce useful physical and chemical changes in a material. A potential application for electron beam processing for composite manufacturing is for curing carbon fiber prepregs. These prepregs, carbon fibers or fabrics preimpregnated with liquid polymer resin, are commonly used in the aircraft industry. Their use, however, can be time consuming and labor intensive. The advantages of radiation curing over thermal or chemical curing methods include improved rate control, reduced curing times, and curing at ambient temperature. There is no need for chemical initiators. A radiation-curable prepreg has been designed to meet the mechanical and physical property specifications of a leading aircraft manufacturing company. The resin is a mixture of an expoxy diacrylate, polybutadiene diacrylate, and a multifunctional monomer. This resin was used to impregnate a plain weave carbon fabric, at a loading of 35 percent (by mass), using a solvent process. Preliminary characterization studies show that the cured polymer produced by irradiation in air to a dose of 40 kGy is amorphous with a maximum gel fraction of 85 percent. The softening point of the polymer varied from 228°C (30-kGy sample) to 237°C (50-kGy sample). The linear thermal expansion coefficient of the polymer was 1.7 × 10−4 m/m°C from 25°C to 150°C and was unaffected by varying the applied dose from 30 to 50 kGy.

Identification du carbonate (BiO) 4 (OH) 2 CO 3 comme intermediaire dans l'interconversion de α-Bi 2 O 3 et de la bismutite synthetique (BiO) 2 CO 3 . Energies de formation de Gibbs, analyse thermogravimetrique, diffraction RX sur poudre et spectrometries IR et Raman. Parametres cristallins

Passivation of threading dislocations in an incommensurate Ge0.36Si0.64/Si structure is studied using hydrogen plasma anneal. The reverse current of pn junction diodes made of the above structure is reduced by more than 30 times after hydrogenation. Associated improvements in the current‐voltage (I‐V) characteristics is also observed. Capacitance‐voltage (C‐V) measurements reveal that the shallow dopants neutralized by hydrogenation reactivate at lower temperatures than the passivated deep level defects. Secondary‐ion mass spectroscopy (SIMS) analysis established the depth of diffusion of hydrogen under the experimental conditions. Work in this direction could eventually lead to the integration of infrared detectors with Si very large scale integration (VLSI).

The spectrum of the solvated electron in D2O has been measured in the temperature range 292–445 K. The results show that Emax varies from 1.80eV at 292 K, to 1.32eV at 445 K, with a temperature coefficient of ∼ 3.2x10-3 eV K-1. The values are consistent with those measured in D2O at higher temperatures and, at low temperatures, do not differ appreciably from those in H2O.

Observations are reported on the interconversion of solid α-Bi2O3, Bi12O17Cl2, BiOCl, and a daubreeite-like phase tentatively identified as Bi2O2(OH)Cl, in aqueous chloride solutions at 25 °C. Equilibrium constants, K, for these interconversions are expressed as anion activity ratios, {Cl−}/{OH−}. Experimental values of K for equilibrium between Bi2O3 and each of the chlorides are 100.56 ± 0.20 for Bi12O17Cl2, 101.5 ± 0.4 for Bi2O2(OH)Cl, and 103.13 ± 0.04 for BiOCl; the fatter two represent metastable equilibria. These equilibrium constants yielded the following estimates of Gibbs energies of formation: Bi12O17Cl2, −3141 ± 6 kJ mol−1;"Bi2O2(OH)Cl", −696 ± 4 kJ mol−1; BiOCl, −321.5 ± 1.3 kJ mol−1. Phase relationships among these solids are discussed, with reference to natural occurrence, other bismuth oxychlorides, and the stability of other basic salts of bismuth.

Four basic lead carbonates were prepared and identified by X-ray powder diffractometry. These were hydrocerussite (Pb3(OH)2(CO3)2), plumbonacrite (Pb10O(OH)6(CO3)6), and the two adducts MOH•2PbCO3 ...