Search

Sol-gel processing of methanol solutions of Cu(II) acetylacetonates was used for obtaining controlled polymerization of the complex molecules. The resulting sols were evaporated and the resulting precipitate was heated until a self-sustaining combustion reaction took place. The simultaneous presence of nitrate ions and the acetylacetonato ligands resulted in a sharp combustion process, characterized by low activation temperature and intense exothermic feature. The same processing was applied to other metals and other ligands, showing that the sol-gel processing of transition metal complexes can be a simple, convenient, flexible generalization of the citrate-nitrate method for preparing precursors for the combustion synthesis of oxide powders. Moreover, the controlled sol-gel processing of the metal complex can be used as a tool for controlling the precursor structure and. hence, the morphology of the final product.

Unconventional lithography (such as nanosphere lithography (NSL) and colloidal lithography (CL)) is an attractive alternative to sequential and very expensive conventional lithography for the low-cost fabrication of large-area nano-optical devices. Among these, nanohole (NH) arrays are widely studied in nanoplasmonics as transducers for sensing applications. In this work, both NSL and CL are implemented to fabricate two-dimensional distributions of gold NHs. In the case of NSL, highly ordered arrays of gold NHs distributed in a hexagonal lattice onto glass substrates were fabricated by a simple and reproducible approach based on the self-assembling of close-packed 500 nm diameter polystyrene particles at an air/water interface. After the transfer onto a solid substrate, the colloidal masks were processed to reduce the colloidal size in a controllable way. In parallel, CL was implemented with short-range ordered gold NH arrays onto glass substrates that were fabricated by electrostatically-driven self-assembly of negatively charged colloids onto a polydiallyldimethylammonium (PDDA) monolayer. These distributions were optimized as a function of the colloidal adsorption time. For both approaches, controllable and reproducible procedures are presented and discussed. The optical responses of the NH structures are related to the short-range ordering level, and their good performances as refractive index transducers are demonstrated.

The outcomes of redo open repair for recurrent thoraco-abdominal aortic aneurysm (TAAA) are usually considered to be poorer when compared with the index procedure; for these reasons, less invasive strategies such as endovascular procedures are especially attractive. However, when the aneurysmal changes involve the visceral vessels such as in the case of visceral aortic patch (VAP) aneurysms, a conventional endovascular approach is not applicable. In this critical situation, a possible alternative to open regrafting is a hybrid treatment consisting of rerouting of visceral arteries, and aneurysm exclusion using commercially available thoracic aortic endografts. In this chapter, we compare the outcomes of our series of patients who, from 2001 to 2009, underwent redo VAP aneurysm open repair with a selected group of high-risk patients who underwent, in the same period, redo VAP aneurysm hybrid repair. We observed similar perioperative mortality and morbidity rates in the two groups of patients, with reduced surgical challenge in the hybrid group, allowing us to avoid redo-thoracotomy, retroperitoneal redissection, and previous thoracic graft reclamping. However, in the hybrid group, new medium-term specifically procedure-related complications have been observed and, until greater experience is available, a widespread use of this technique should currently be limited in this specific subset of high-risk patients.

In this paper, a double-axis planar micro-fluxgate magnetic sensor and its front-end circuitry are presented. The ferromagnetic core material, i.e., the Vitrovac 6025 X, has been deposited on top of the coils with the dc-magnetron sputtering technique, which is a new type of procedure with respect to the existing solutions in the field of fluxgate sensors. This procedure allows us to obtain a core with the good magnetic properties of an amorphous ferromagnetic material, which is typical of a core with 25-mum thickness, but with a thickness of only 1 mum, which is typical of an electrodeposited core. The micro-Fluxgate has been realized in a 0.5- mum CMOS process using copper metal lines to realize the excitation coil and aluminum metal lines for the sensing coil, whereas the integrated interface circuitry for exciting and reading out the sensor has been realized in a 0.35-mum CMOS technology. Applying a triangular excitation current of 18 mA peak at 100 kHz, the magnetic sensitivity achieved is about 10 LSB/muT [using a 13-bit analog-to-digital converter (ADC)], which is suitable for detecting the Earth's magnetic field (plusmn60 muT), whereas the linearity error is 3% of the full scale. The maximum angle error of the sensor evaluating the Earth magnetic field is 2deg. The power consumption of the sensor is about 13.7 mW. The total power consumption of the system is about 90 mW.

In this paper a double axis planar micro-Fluxgate magnetic sensor is presented. The ferromagnetic core material, the Vitrovac 6025 X, has been deposited on top of the coils with the DC-magnetron sputtering technique, a new type of procedure with respect the existing solutions in the field of Fluxgate sensor. This procedure allows us to obtain a core with the good magnetic properties of the amorphous ferromagnetic material, typical of a core 25 p.m thick, but with a thickness of only 1 μm, typical of a core electrodeposited. The micro-Fluxgate has been realized in a 0.5 μm CMOS process using copper metal lines to realize the excitation coil and aluminum metal lines for the sensing coils. Applying a triangular excitation current of 18 mA peak at 100 kHz the magnetic sensitivity achieved is about 0.45 mV/μT, suitable for detecting the Earth's magnetic field (±50 μT), while the linearity error is 1.15% of the full scale. The maximum angle error of the sensor, evaluating the Earth magnetic field, is 3.4°. The power consumption of the sensor is about 13.7 mW. ©2006 IEEE.

A complete vector-2D integrated microsensor system for magnetic field measurement is proposed. The system consists of a micro-integrated fluxgate magnetometer with front-end electronic circuitry based on second-harmonic detection. The magnetic core of the sensor is realized with the VITROVAC 6025X deposited over the micro-integrated coils with the dc-magnetron sputtering deposition process. The sensor realized shows a linearity error of about 1.15% of the full scale in the range of +/- 50 mu T with a sensitivity of 0.45 mV/mu T. (c) 2006 Elsevier B.V. All rights reserved.