Resist Heating Effect Research Articles

Efficiency and safety of high-power ablation guided by Lesion size index: An ex vivo porcine heart study.

Although Lesion size index (LSI) has been reported to highly predict radiofrequency lesion size in vitro, its accuracy in lesion size and steam pop estimation has not been well investigated for every possible scenario. Initially, radiofrequency ablations were performed on porcine myocardial slabs at various power, CF, and time settings with blinded LSI. Subsequently, radiofrequency power at 20, 30, 40, 50, and 60W was applied at CF values of 5, 10, 20, and 30g to reach target LSIs of 4, 5, 6, and 7. Lesion size and steam pops were recorded for each ablation. Lesion size was positively correlated with LSI regardless of power settings (p<0.001). The linear correlation coefficients of lesion size and LSI decreased at higher power settings. At high power combined with high CF settings (50W/20 g), lesion depth and LSI showed an irrelevant correlation (p=0.7855). High-power ablation shortened ablation time and increased the effect of resistive heating. LSI could predict the risk of steam pops at high-power settings with the optimal threshold of 5.65 (sensitivity, 94.1%; specificity, 46.1%). The ablation depth of the heavy heart was shallower than that of the light heart under similar ablation settings. LSI could predict radiofrequency lesion size and steam pops at high power settings in vitro, while synchronous high power and high CF should be avoided. Lighter hearts require relatively lower ablation settings to create appropriate ablation depth.

Effect of resistive heating on the bond properties between iron-based shape memory bars and cement mortar

Iron-based shape memory alloys (Fe-SMAs) have been widely studied as a new type of prestressing material for near-surface mounted (NSM) or external strengthening, and have been used in numerous strengthening projects in Europe. However, Fe-SMAs have not been widely used in new structures due to their uncertain bond properties after high-temperature activation. Therefore, a new type of application in new structures is proposed, which is composed of Fe-SMA bars, plastic corrugated pipes and high-temperature-resistant cement mortar. The bond properties between Fe-SMA bars and cement mortar after resistive heating were investigated through pull-out tests. The influence of different heating temperatures and heating times on the bond properties was analyzed. It was shown that when the temperature of the inner Fe-SMA bars was 150 °C–350 °C, the surface temperature of the plastic corrugated pipes was only 35 °C–65 °C, which indicated that the activation process would not transfer excessive heat to the concrete outside the plastic corrugated pipes. With the increase of the heating temperature, the ultimate bond strength, bond stiffness, residual bond stress, and energy dissipation all gradually decreased. Compared with the specimens at ambient temperature, the specimens could still maintain a high ultimate bond strength with only approximately 10% loss after being heated to 200 °C and cooled down. When the activation temperature was below 300 °C, the more serious bond degradation could be observed with the longer heating time. However, when the temperature exceeded 300 °C, the influence of heating time was negligible. In addition, prediction models for the ultimate bond strength and the bond-slip curves were proposed, which could provide references for subsequent studies.

Self-similar solutions for resistive diffusion, Ohmic heating, and Ettingshausen effects in plasmas of arbitrary β

Magneto-inertial fusion (MIF) approaches, such as the MagLIF experiment, use magnetic fields in dense plasma to suppress cross-field thermal conduction, attempting to reduce heat loss and trap alpha particles to achieve ignition. However, the magnetic field can introduce other transport effects, some of which are deleterious. An understanding of these processes is thus crucial for accurate modeling of MIF. We generalize past work exploiting self-similar solutions to describe transport processes in planar geometry and compare the model to the radiation-magnetohydrodynamics (MHDs) code Chimera. We solve the 1D extended MHD equations under pressure balance, making no assumptions about the ratio of magnetic and thermal pressures in the plasma. The resulting ordinary differential equation (ODE) boundary value problem is solved using a shooting method, combining an implicit ODE solver and a Newton–Raphson root finder. We show that the Nernst effect dominates over resistive diffusion in high β plasma, but its significance is reduced as the β decreases. On the other hand, we find that Ettingshausen and Ohmic heating effects are dominant in low β plasma and can be observable in even order unity β plasma, though in the presence of a strong temperature gradient heat conduction remains dominant. We then present a test problem for the Ohmic heating and Ettingshausen effects which will be useful to validate codes modeling these effects. We also observe that the Ettingshausen effect plays a role in preventing temperature separation when Ohmic heating is strong. Neglecting this term may lead to overestimates for the electron temperature at a vacuum–plasma interface, such as at the edge of a z-pinch. The model developed can be used to provide test problems with arbitrary boundary conditions for magnetohydrodynamics codes with the ability to freely switch on terms to compare their individual implementations.

Simulation of thermal processes of shaft plasma furnace for waste gasification

Mathematical modeling of a part of a mine plasma electric furnace for waste gasification is presented. In model calculations, the study of the effect of additional resistive heating as an in-furnace process of drying waste was carried out. In the course of modeling, the electrical resistance of the waste at natural moisture was taken into account. A study was carried out to identify the uniform release of energy inside the waste batch in the drying zone with different connections of the electrodes and the type of current.

Highly Multifunctional GNP/Epoxy Nanocomposites: From Strain-Sensing to Joule Heating Applications.

A performance mapping of GNP/epoxy composites was developed according to their electromechanical and electrothermal properties for applications as strain sensors and Joule heaters. To achieve this purpose, a deep theoretical and experimental study of the thermal and electrical conductivity of nanocomposites has been carried out, determining the influence of both nanofiller content and sonication time. Concerning dispersion procedure, at lower contents, higher sonication times induce a decrease of thermal and electrical conductivity due to a more prevalent GNP breakage effect. However, at higher GNP contents, sonication time implies an enhancement of both electrical and thermal properties due to a prevalence of exfoliating mechanisms. Strain monitoring tests indicate that electrical sensitivity increases in an opposite way than electrical conductivity, due to a higher prevalence of tunneling mechanisms, with the 5 wt.% specimens being those with the best results. Moreover, Joule heating tests showed the dominant role of electrical mechanisms on the effectiveness of resistive heating, with the 8 wt.% GNP samples being those with the best capabilities. By taking the different functionalities into account, it can be concluded that 5 wt.% samples with 1 h sonication time are the most balanced for electrothermal applications, as shown in a radar chart.

Cyclic Olefin Copolymer Interleaves for Thermally Mendable Carbon/Epoxy Laminates.

Thin cyclic olefin copolymer (COC) foils were used as intrinsic thermoplastic healing agents in carbon fiber (CF)-reinforced epoxy laminates. COC films were produced by hot pressing and were interleaved in the interlaminar regions between each EP/CF lamina, during the hand layup fabrication of the laminates. Three samples were produced, i.e., the neat EP/CF laminate without COC, and two laminates containing COC layers with a thickness of 44 μm and 77 μm, respectively. It was observed that the fiber volume fraction decreased, and the porosity increased with the introduction of COC layers, and this effect was more evident when thick films were used. These two effects, combined with the sub-optimal adhesion between COC and EP, caused a decrease in the mechanical properties (i.e., the elastic modulus, flexural strength, interlaminar shear strength and interlaminar fracture toughness) of the laminates. Specimens subjected to mode I interlaminar fracture toughness test were then thermally mended under pressure by resistive heating, through the Joule effect of conductive CFs. A temperature of approximately 190 °C was reached during the healing treatment. The healing efficiency was evaluated as the ratio of critical strain energy release rate (GIC) of the healed and virgin specimens. Healed specimens containing COC layers of 44 μm and 77 μm exhibited a healing efficiency of 164% and 100%, respectively. As expected, the healing treatment was not beneficial for the neat EP/CF laminate without COC, which experienced a healing efficiency of only 2%. This result proved the efficacy of COC layers as a healing agent for EP/CF laminates, and the effectiveness of resistive heating as a way to activate the intrinsic healing mechanism.

Effect of resistive heating on incessantly poignant thin needle in magnetohydrodynamic Sakiadis hybrid nanofluid

The flow and energy transport of water-ethylene glycol (EG) based Ti-Cu hybrid nanofluid due to incessantly poignant needle in magnetohydrodynamic Sakiadis flow with resistive heating is investigated. We scrutinized the flow and heat transfer of the Blasius and free stream flows. The governing Partial Differential Equations are transformed as Ordinary Differential Equations using suitable similarities and resolved numerically using RK (Runge-Kutta) based shooting procedure. Numerical and graphical outcomes are explored and examined for the drive, thermal transport, surface friction and local Nusselt number of various pertinent parameters. It is originate that the flow and thermal boundary layer of Blasius and Sakiadis flows are not equal. The rate of energy transport is high in moving needle in the static fluid when equated with the fixed needle in dynamic fluid. It is also established that the rate of heat transfer in Ti-Cu/EG-water hybrid nanofluid is more than water-EG/Ti nanofluid.

Effectiveness of application of carbon-fibre polymer-fabric resistive heating compared with forced-air warming to prevent unintentional intraoperative hypothermia in patients undergoing elective abdominal operations: A systematic review and meta-analysis of randomised controlled trials.

Unintentional intraoperative hypothermia was regarded as a common intraoperative symptom with serious complications. The active warming strategies of forced-air warming (FAW) and carbon-fibre polymer-fabric resistive heating were considered to be effective interventions for preventing hypothermia. However, the effectiveness of them was not reported consistently. To evaluate the effectiveness of carbon-fibre polymer-fabric resistive heating compared with FAW in preventing hypothermia in patients undergoing elective surgeries. Systematic review and meta-analysis. A rigorous systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis reporting checklist. Searching strategy was undertaken on the electronic databases of Cumulative Index to Nursing and Allied Health Literature, MEDLINE, PubMed, EMBASE and Medical Literature Retrieval Service. The assessment of study quality was performed through risk of bias of Cochrane handbook of systematic review of interventions. Data synthesis was conducted through meta-analysis with sensitive analysis. The quality of evidence was graded using Grading of Recommendations Assessment, Development and Evaluation approach. A total of five randomised controlled trials with 282 patients undergoing elective surgeries were included in the quantitative synthesis. Four studies concluded that FAW was as effective as carbon-fibre polymer-fabric resistive heating in preventing hypothermia. However, one study yielded a different conclusion that the efficacy of FAW was superior to carbon-fibre polymer-fabric resistive heating with small incidence of hypothermia. Meta-analysis found that FAW was more effective than carbon-fibre polymer-fabric resistive heating in preventing hypothermia. In the elective abdominal surgery, carbon-fibre polymer-fabric resistive heating was less effective than FAW on the prevention of hypothermia. However, hypothermia still occurred in the FAW group. It was more objective to assess the efficacy of warming technology combining the incidence of hypothermia and the core body temperature together, which was suggested for further research.

Far-field midinfrared superresolution imaging and spectroscopy of single high aspect ratio gold nanowires

Limited approaches exist for imaging and recording spectra of individual nanostructures in the midinfrared region. Here we use infrared photothermal heterodyne imaging (IR-PHI) to interrogate single, high aspect ratio Au nanowires (NWs). Spectra recorded between 2,800 and 4,000 cm-1 for 2.5-3.9-μm-long NWs reveal a series of resonances due to the Fabry-Pérot modes of the NWs. Crucially, IR-PHI images show structure that reflects the spatial distribution of the NW absorption, and allow the resonances to be assigned to the m = 3 and m = 4 Fabry-Pérot modes. This far-field optical measurement has been used to image the mode structure of plasmon resonances in metal nanostructures, and is made possible by the superresolution capabilities of IR-PHI. The linewidths in the NW spectra range from 35 to 75 meV and, in several cases, are significantly below the limiting values predicted by the bulk Au Drude damping parameter. These linewidths imply long dephasing times, and are attributed to reduction in both radiation damping and resistive heating effects in the NWs. Compared to previous imaging studies of NW Fabry-Pérot modes using electron microscopy or near-field optical scanning techniques, IR-PHI experiments are performed under ambient conditions, enabling detailed studies of how the environment affects mid-IR plasmons.

Theoretical study on effects of electron thermal energy on sensitization process of chemically amplified electron beam resists—contribution to resist heating effect in electron beam mask writing

The elevation of resist temperature during exposure to electron beam (EB) deforms the patterns of chemically amplified resists. The resist heating effect is a significant problem in mask production using a high-current EB mask writer. However, its mechanism is still unknown. In this study, the effects of electron thermal energy on the sensitization process of chemically amplified EB resists were investigated using simulation on the basis of their sensitization mechanism. The decomposition yield of sensitizers increased with resist temperature. The effect of the increase of decomposition yield on the critical dimension (CD) was calculated on the basis of the reaction mechanism. When the exposure pattern width was set to the same as the half-pitch (16 nm), the values of dCD/dT were 0.019, 0.013 and 0.010 nm K−1 for the sensitizer concentrations of 0.2, 0.3 and 0.4 (molecules) nm−3, respectively. dCD/dT was decreased by decreasing the exposure pattern width.

Numerical study on the effect of additional resistive heating and crystal rotation on sapphire single crystals (Al2O3) grown by the Kyropoulos method

Reduction of melt–crystal interface convexity during Kyropoulos growth of sapphire single crystals through rotation and crucible bottom heating.

Effect of Resistive and Plasma Heating on the Specific Impulse of a Ceramic Cold Gas Thruster

The research and development of small satellites has continued to expand over the last decades. However, the propulsion systems with adequate performance have persisted to be a great challenge. In this paper, the effects of three different heaters on the specific impulse and overall thrust efficiency of a cold gas microthruster are presented. They consisted of a conventional, printed resistive thick-film element, a freely suspended wire, and a stripline split-ring resonator microplasma source, and were integrated in a single device made from the high-temperature co-fired ceramics. The devices were evaluated in two setups, where the first measured thrust and the other measured shock cell geometry. In addition, the resistive elements were evaluated as gas temperature sensors. The microplasma source was found to provide the greatest improvement in both specific impulse and thrust efficiency, increasing the former from an un-heated level of 44–56 s when heating with a power of 1.1 W. This corresponded to a thrust efficiency of 55%, which could be compared with the results from the wire and printed heaters which were 51s and 18%, and 45s and 14%, respectively. The combined results also showed that imaging the shock cells of a plasma heated thruster was a simple and effective way to determine its performance, when compared to the traditional thrust balance method. [2018-0178]

Why Broadgate Phase 8 composite floor did not fail under fire

PurposeThis paper aims to present the findings of a numerical investigation into the performance of the steel-concrete composite floor involved in Broadgate Phase 8 fire.Design/methodology/approachThe investigation is conducted by carrying out a 3-D thermomechanical analysis of a composite floor similar to the one involved in the fire using ANSYS. Four fire scenarios are investigated, with each producing a unique stress – strain pattern. The results obtained are compared with the observations made after the fire and inferences drawn.FindingsThe results obtained are found to be correlated with the observations made after the fire. The performance of the composite floor is found to be dominated by development of large strains, leading to large deflections. Furthermore, colder parts of the structure, through redistribution of forces, are found to have a profound impact on the ability of a composite floor to resist heating effects. From the findings, it is concluded that connections’ design, occurrence of membrane action and thermal restraints were the key reasons the floor did not fail.Originality valueThe study takes a more forensic approach. This is a departure from majority of published literature, where comparison is usually between experimental and numerical results. By comparing the findings from a real fire with those of a numerical investigation, the study provides an insight into the accuracy of applying numerical models for the prediction of effects of fire on structural behaviour.

Electrosynthesis of Glycerol Carbonate from Glycerol and Potassium Carbonate on Nickel Electrodes

The growing biodiesel industry leads to an excess production of glycerol by-product which is of low value but costly to store or dispose because glycerol is not suitable as fuel due to its sooty flame while its discharge to water leads to eutrophication. On the other hand, industrial carbon dioxide could be readily captured by scrubbing with potassium hydroxide to form potassium carbonate. With the tightening of greenhouse gas emission standards and the introduction of carbon cap and trade quota, carbon utilization becomes increasingly important both on environment and economic perspective. The combination of glycerol and carbon dioxide, in the form of dissolved carbonate ions, to produce glycerol carbonate would solve both glycerol and carbon dioxide emission problems altogether. In addition, glycerol carbonate is a valuable chemical feedstock in high industrial demand for its widespread use as solvents, surfactants, chemical feedstock and polymer materials. Compared to conventional catalysis, the electrochemical route dramatically reduces heating and pressurization requirement without using noble metal catalysts. The electrochemical synthesis of glycerol carbonate from glycerol and potassium carbonate enables utilizing electrical power to upgrade the glycerol waste into valuable glycerol carbonate while consuming carbon dioxide, under much milder conditions. The electrosynthesis of glycerol carbonate has been performed under ambient temperature and pressure on nickel plate electrodes, using potassium carbonate dissolved in glycerol with varying water dilution. The formation of glycerol carbonate was confirmed by both the characteristic peak on Cyclic Voltammetry and the Liquid Chromatography-Mass Spectrometry (LC-MS) analysis. Interestingly, comparison of LC-MS spectra with the analytical standard showed the carbonate insertion into glycerol molecule to be regiospecific, producing exclusively the more common and valuable 5-membered-ring glycerol 1,2 carbonate, instead of 6-membered-ring glycerol 1,3 carbonate. Based on this observation, it was postulated that the reaction occurred by simultaneous attack of 1,2 -OH groups of glycerol, making 1,3 bond formation impossible due to insufficient molecular “arm” length of carbonate species. LC-MS analysis revealed further C=O bond hydrogenation of glycerol 1,2 carbonate to 4-(Hydroxymethyl)-1,3-dioxolan-2-ol and dimerization of glycerol carbonate. The glycerol carbonate hydrogenation was found to be favorable under low current density such that most of glycerol carbonate formed was hydrogenated. The color change from colorless to brown of reaction mixture indicated the electrochemical dehydrogenation of glycerol to acrolein followed by subsequent polymerization to brown polyacrolein as by-product, similar to the color change observed for mixture after intense heating. Under high current density, both the polyacrolein formation and the hydrogen evolution were found to be more prevalent due to a combined effect of electrochemical polarization and local resistive heating, reducing reaction selectivity and energy efficiency. Addition of water is found to be beneficial by reducing heating requirement, resistive loss and side reactions. From the results, the novel electrochemical upgrading of glycerol waste while utilizing carbon dioxide is successfully demonstrated. However, by-product formation and energy efficiency challenges remain to be overcome for economic viability as the future “green” industrial production of valuable glycerol carbonate. While this discovery of the alternative glycerol electrochemical carbonatation has shed some light into the possible reaction mechanism, further mechanistic study is needed for better understanding of the reaction mechanism. Figure 1

Correction of resist heating effect on variable shaped beam mask writer

The specifications for critical dimension (CD) accuracy and line edge roughness are getting tighter to promote every photomask manufacturer to choose electron beam resists of lower sensitivity. When the resist is exposed by too many electrons, it is excessively heated up to have higher sensitivity at a higher temperature, which results in degraded CD uniformity. This effect is called “resist heating effect” and is now the most critical error source in CD control on a variable shaped beam (VSB) mask writer. We have developed an on-tool, real-time correction system for the resist heating effect. The system is composed of correction software based on a simple thermal diffusion model and computational hardware equipped with more than 100 graphical processing unit chips. We have demonstrated that the designed correction accuracy was obtained and the runtime of correction was sufficiently shorter than the writing time. The system is ready to be deployed for our VSB mask writers to retain the writing time as short as possible for lower sensitivity resists by removing the need for increased pass count.

Time-resolved Kα spectroscopy measurements of hot-electron equilibration dynamics in thin-foil solid targets: collisional and collective effects

Time-resolved Kα spectroscopy measurements from high-intensity laser interactions with thin-foil solid targets are reviewed. Thin Cu foils were irradiated with 1−10 J, 1 ps pulses at focused intensities from 1018 to 1019 W cm−2. The experimental data show Kα-emission pulse widths from 3 to 6 ps, increasing with laser intensity. The time-resolved Kα-emission data are compared to a hot-electron transport and Kα-production model that includes collisional electron–energy coupling, resistive heating, and electromagnetic field effects. The experimental data show good agreement with the model when a reduced ponderomotive scaling is used to describe the initial mean hot-electron energy over the relevant intensity range.

Electrical and ionic conductivity effects on magic-angle spinning nuclear magnetic resonance parameters of CuI

We investigate experimentally and theoretically the effects of two different types of conductivity, electrical and ionic, upon magic-angle spinning NMR spectra. The experimental demonstration of these effects involves (63)Cu, (65)Cu, and (127)I variable temperature MAS-NMR experiments on samples of γ-CuI, a Cu(+)-ion conductor at elevated temperatures as well as a wide bandgap semiconductor. We extend previous observations that the chemical shifts depend very strongly upon the square of the spinning-speed as well as the particular sample studied and the magnetic field strength. By using the (207)Pb resonance of lead nitrate mixed with the γ-CuI as an internal chemical shift thermometer we show that frictional heating effects of the rotor do not account for the observations. Instead, we find that spinning bulk CuI, a p-type semiconductor due to Cu(+) vacancies in nonstoichiometric samples, in a magnetic field generates induced AC electric currents from the Lorentz force that can resistively heat the sample by over 200 °C. These induced currents oscillate along the rotor spinning axis at the spinning speed. Their associated heating effects are disrupted in samples containing inert filler material, indicating the existence of macroscopic current pathways between micron-sized crystallites. Accurate measurements of the temperature-dependence of the (63)Cu and (127)I chemical shifts in such diluted samples reveal that they are of similar magnitude (ca. 0.27 ppm/K) but opposite sign (being negative for (63)Cu), and appear to depend slightly upon the particular sample. This relationship is identical to the corresponding slopes of the chemical shifts versus square of the spinning speed, again consistent with sample heating as the source of the observed large shift changes. Higher drive-gas pressures are required to spin samples that have higher effective electrical conductivities, indicating the presence of a braking effect arising from the induced currents produced by rotating a conductor in a homogeneous magnetic field. We present a theoretical analysis and finite-element simulations that account for the magnitude and rapid time-scale of the resistive heating effects and the quadratic spinning speed dependence of the chemical shift observed experimentally. Known thermophysical properties are used as inputs to the model, the sole adjustable parameter being a scaling of the bulk thermal conductivity of CuI in order to account for the effective thermal conductivity of the rotating powdered sample. In addition to the dramatic consequences of electrical conductivity in the sample, ionic conductivity also influences the spectra. All three nuclei exhibit quadrupolar satellite transitions extending over several hundred kilohertz that reflect defects perturbing the cubic symmetry of the zincblende lattice. Broadening of these satellite transitions with increasing temperature arises from the onset of Cu(+) ion jumps to sites with different electric field gradients, a process that interferes with the formation of rotational echoes. This broadening has been quantitatively analyzed for the (63)Cu and (65)Cu nuclei using a simple model in the literature to yield an activation barrier of 0.64 eV (61.7 kJ/mole) for the Cu(+) ion jumping motion responsible for the ionic conductivity that agrees with earlier results based on (63)Cu NMR relaxation times of static samples.

Effect of dc on the Formability of Ti–6Al–4V

Recent research has demonstrated that the mechanical properties of metals are altered when an electrical current is passed through the material. These studies suggest that titanium alloys, due to their low formability and need for dramatic improvement, should be subjected to additional study. The research presented herein further investigates the use of electricity to aid in the bulk deformation of Ti–6Al–4V under tensile and compressive loads. Extensive testing is presented, which documents the changes that occur in the formability of titanium due to the presence of an electrical current at varying current densities. Using carefully designed experiments, this study also characterizes and isolates the effect of resistive heating from the overall effect due to the electrical flow. This study clearly indicates that electrical flow affects the material beyond that which can be explained through resistive heating. The results demonstrate that an applied electrical current within the material during mechanical loading can greatly decrease the force needed to deform the titanium while also dramatically enhancing the degree to which it can be worked without fracturing. Isothermal testing further demonstrates that the changes are significantly beyond that which can be accounted for due to increases in the titanium’s temperature. The results are also supported by data from tests using pulsed and discontinuously applied current. Furthermore, current densities are identified that cause an enhanced formability behavior to occur. Overall, this work fully demonstrates that an electrical current can be used to significantly improve the formability of Ti–6Al–4V and that these improvements far exceed that which can be explained by resistive heating.

Gold‐Tip Electrodes—A New “Deep Lesion” Technology for Catheter Ablation? In Vitro Comparison of a Gold Alloy Versus Platinum–Iridium Tip Electrode Ablation Catheter

Gold-tip electrodes. Radiofrequency (RF) catheter ablation is widely used to induce focal myocardial necrosis using the effect of resistive heating through high-frequency current delivery. It is current standard to limit the target tissue-electrode interface temperature to a maximum of 60-70 degrees C to avoid char formation. Gold (Au) exhibits a thermal conductivity of nearly four times greater than platinum (Pt-Ir) (3.17 W/cm Kelvin vs 0.716 W/cm Kelvin), it was therefore hypothesized that RF ablation using a gold electrode would create broader and deeper lesions as a result of a better heat conduction from the tissue-electrode interface and additional cooling of the gold electrode by "heat loss" to the intracardiac blood. Both mechanisms would allow applying more RF power to the tissue before the electrode-tissue interface temperature limit is reached. To test this hypothesis, we performed in vitro isolated liver and pig heart investigations comparing lesion depths of a new Au-alloy-tip electrode to standard Pt-Ir electrode material. Mean lesion depth in liver tissue for Pt-Ir was 4.33+/-0.45 mm (n=60) whereas Au electrode was able to achieve significantly deeper lesions (5.86+/-0.37 mm [n=60; P<0.001]). The mean power delivered using Pt-Ir was 6.95+/-2.41 W whereas Au tip electrode delivered 9.64+/-3.78 W indicating a statistically significant difference (P<0.05). In vitro pig heart tissue Au ablation (n=20) increased significantly the lesion depth (Au: 4.85+/-1.01 mm, Pt-Ir: 2.96+/-0.81 mm, n=20; P<0.001). Au tip electrode again applied significantly more power (P<0.001). Gold-tip electrode catheters were able to induce deeper lesions using RF ablation in vitro as compared to Pt-Ir tip electrode material. In liver and in pig heart tissue, the increase in lesion depth was associated with a significant increase in the average power applied with the gold electrode at the same level of electrode-tissue temperature as compared to platinum material.

Proximity and heating effects during electron-beam patterning of ultraviolet lithography masks

Proximity effects and resist heating during high energy electron-beam (e-beam) patterning of extreme ultraviolet lithography (EUVL) mask were investigated for the 50 nm node and beyond. These effects were observed experimentally on both silicon wafers and standard 6025 photomasks coated with two different EUVL absorber stacks. Monte Carlo and resist simulations were used for proximity effect correction and resist heating effect verification. The estimated temperature change during electron-beam writing was also attempted using the finite element method.