Effect Of Target Temperature Research Articles

First-principles simulation of the electronic stopping power of He ions in Al at finite temperature

The electronic stopping power of low-energy He projectile particles moving through an Al film under channeling and off-channeling trajectories and its temperature dependence are studied by combining the time-dependent density-functional-theory method with molecular dynamics simulations. The results show that the effect of target temperature on target stopping power can be divided into two aspects which are derived from the target electron and target ion. Below 500 K, the effect of the target-electron temperature on target stopping power is almost negligible. The influence of the target-ion temperature on target stopping power can be divided into two aspects which are derived from the displacement and energy dissipation of target ions. The displacement of the target ion can result in two trends that change the target stopping power: (1) The target ion is closer to the center of lattice channel after displacement, which leads to the increase of target stopping power. (2) The target ion is farther away from the center of the lattice channel after displacement, which leads to the decrease in target stopping power. As the temperature increases, the target ions are more likely to appear farther away from the lattice channel than closer to the center of the lattice channel, so the average displacement of the target ions will lead to a decreasing trend of the target stopping power with the increase of temperature. Under the condition of a given ionic density in the target, the energy dissipation capacity of target ions increases with the increase of temperature, resulting in the tendency of the target stopping power to increase with the increase of temperature. Our calculated stopping powers are in good agreement with the experimental data and reproduced the deviation from velocity proportionality found in the experimental results for a ${\mathrm{He}}^{+}$ ion in Al, validating our approach and numerical implementation.

Effects of target temperature on thermal damage during temperature-controlled MWA of liver tumor

Microwave ablation (MWA) is one among the cancer treatment techniques applied in clinical treatment. This technique is based on rising the temperature within the tissue and the radiation dose absorbed by the cells. The goal of this study is to improve the accuracy of temperature simulation during temperature-controlled MWA of liver tumor. A two-dimensional numerical model of liver tissue has been built and solved using the Finite Element Method (FEM). The bio-heat equation, the first-order Arrhenius rate equations, and the Maxwell equations are employed to simulate the cancer cells necrosis. For heat control, an input microwave power source was controlled by a proportional-integral-derivative (PID) controller to keep the target tip temperature below the preset temperature value during MWA. The effect of the target tip temperature on the applied input microwave power has been investigated in liver tissue. Further, the thermal damage fraction and the time required for complete necrosis liver cancer are also evaluated. The present results show that the specific absorption rate (SAR) and the temperature distribution are highly influenced by the target tip temperature. Optimal treatment period for total tumor ablation will offers a significant way to reduce damage to the surrounding healthy cells and providing safe use of MWA and without risk.

Compression after impact behavior of carbon/epoxy composite sandwich panels with Nomex honeycomb core subjected to low velocity impacts at extreme cold temperatures

The effect of temperature during impact on the compression after impact behavior of carbon/epoxy composite sandwich panels with Nomex honeycomb core is investigated. Impact tests were performed at room temperature, −70 °C, and −150 °C, while compression after impact tests on the damaged panels are performed at room temperature in order to isolate the effect of temperature during impact on the residual compressive strength and failure modes. Results show that there is almost no effect of target temperature at impact on the residual compressive strength of the damaged panels, although target temperature affects the damage induced by impact loading. Moreover, the effect of impact temperature on the residual compressive strength is negligible when compared to the strength reduction between pristine panels and the panels with the least amount of damage tested in this study.

Design, Development and Performance Evaluation of Eddy Current Displacement Sensor Based Pressure Sensor with Target Temperature Compensation

In Aerospace applications, pressure measurement plays a vital role as it serves as one of the input to onboard controller to aid decision- making on initiating or terminating some of the critical events. In this paper, the design aspects of pressure sensor using linear eddy current displacement sensor (ECDS) are presented along with its performance evaluation. The static calibration is carried out to select the best position of ECDS in the proposed pressure sensor. The effect of target temperature on sensor output is presented with test results to aid compensation. A compensation algorithm is developed to minimise the error due to target temperature. The developed compensation algorithm is validated using thermal calibration. The designed pressure sensor is calibrated using Arson dynamic pressure calibrator to evaluate its bandwidth. The calibration results are analysed to aid future sensor design towards improvement of accuracy, bandwidth and miniaturisation.

Abstract 18190: Associations Between Endothelial Injury, Severity of Post-cardiac Arrest Syndrome and Mortality After Out-of-hospital Cardiac Arrest

Background: Post-cardiac arrest syndrome (PCAS) is characterized by systemic inflammation and endothelial dysfunction, which may exacerbate organ failure and may be related to adverse outcome. We sought to investigate the associations between trombomodulin (TM), a marker of endothelial cell injury, and severity of PCAS and the possible prognostic importance in comatose survivors of out-of-hospital cardiac arrest treated with targeted temperature management (TTM). Methods: We included 163 patients, randomly assigned to TTM at 33°C or 36°C for 24 h in the TTM-trial at a single center. Serum TM was analyzed at 0, 24, 48 and 72 hours after cardiac arrest and stratified in median value of TM for outcome analysis at each time point to a high or low TM group. Severity of PCAS was assessed daily by the Sequential Organ Failure Assessment score. Survival status was recorded at 180 days. Results: Corresponding values of TM and severity of PCAS correlated at each time point, baseline (r=0.31, p=0.0001), 24 h (r=0.52, p<0.0001), 48 h (r=0.50, p<0.0001) and 72 h (r=0.36, p<0.0001). Levels of TM changed significantly within the first 3 days (p<0.0001) with no significant difference between temperature groups, p interaction =0.32. At 24 h, the 180-day mortality rate in patients with high TM levels (> 6.9 ng·ml -1 = median) was 42% compared to 18% in patients with low TM levels, p=0.002 (Figure), corresponding to an unadjusted hazard ratio of 2.6 (95%CI: 1.4-4.9), p=0.003. When adjusting for pre-hospital prognostic factors the hazard ratio for high TM levels at 24 h was 1.5 (95%CI: 0.7-3.1), p=0.31, with no significant interaction between level of TM and TTM-group, p=0.74. Analysis of TM at 48 and 72 hours showed similar results. Conclusions: Levels of TM are significantly elevated and associated with severity of PCAS with no effect of target temperature at 33°C or 36°C. High TM levels were associated with increased mortality, but the association was explained by confounding factors.

OS9-12 Effects of Target Temperature on Size Distribution of Ejecta in Hypervelocity Impact : For revision of ISO 11227(Shock and Hypervelocity Impact,OS9 Recent advances in impact engineering,STRENGTH OF MATERIALS)

OS9-12 Effects of Target Temperature on Size Distribution of Ejecta in Hypervelocity Impact : For revision of ISO 11227(Shock and Hypervelocity Impact,OS9 Recent advances in impact engineering,STRENGTH OF MATERIALS)

Thermal shock modeling of Ultra-High Temperature Ceramics under active cooling

Thermal shock resistance is one of the most important parameters in Ultra-High Temperature Ceramics (UHTCs) since it determines their performance in various applications. In this paper, due to the fact that the material parameters of UHTCs are very sensitive to the variations of temperature, the temperature-dependent thermal shock resistance parameters of UHTCS are studied using an analytical model. The effects of target temperature on the thermal shock behavior of UHTCs thermal protection system (TPS) under active cooling are examined. The calculated results show that thermal shock behavior of the UHTCs’ TPS is strongly affected by the target temperature.

Deposition of Zr–ZrO X and Y–Y XO Y films by reactive magnetron sputtering

The effect of target temperature in reactive magnetron sputtering of Zr and Y has been investigated by studying the effect of hot and cold targets on process conditions. The effect of discharge power and oxygen flow were studied and measurements made of deposition rates which were found to mainly depend on oxygen flow rate. The use of the hot-cathode technique allowed increases in deposition rate to be made and measurements showed that voltage–current characteristics were significantly different from those of normal magnetron sputtering. Films of Zr–ZrO X and Y–Y X O Y were deposited and their structure analyzed using X-ray diffraction (XRD) which showed that single-phase oriented monoclinic ZrO 2 films, with relatively large deposition rates (∼1.5 nm/s) can be produced using the “hot’’ target technique.

Dependence of nitriding degree of Ti surface by non-LTE nitrogen plasma on various plasma parameters

Experiments of plasma nitriding of titanium are carried out by two plasma sources. One is a microwave discharge plasma source under several Torr, and the other is a nitrogen arc jet generated under atmospheric pressure followed by rapid expansion into a gas wind tunnel. The relationship between the surface density of nitrogen atoms in the α-Ti and various plasma parameters is systematically studied. For the microwave nitrogen plasma, it is found that the effect of the vibration temperature is the most essential for the surface nitriding, whereas the effect of electron temperature, density and rotation temperature is less remarkable. It is also found that the higher vibration temperature of the microwave discharge nitrogen plasma makes the target temperature higher, and consequently, the surface density of atomic nitrogen remarkably increased. However, the effect of target temperature is less remarkable for the arc jet nitrogen plasma.

Blister formation in tungsten by hydrogen and carbon mixed ion beam irradiation

Blister formation in tungsten has been studied by mixed carbon and hydrogen ion beam irradiation. The beam ion energies were 1.0 keV and 300 eV, and the fluence was in the range of 10 24–10 25 ions m −2. It was found that a little amount of carbon impurity in the beam affected blister formation. A large number of blisters with various sizes were observed on the surface of tungsten at 653 K when the carbon concentration was more than 0.35%. When the carbon concentration was 0.11%, no blisters larger than 1.0 μm were observed. When the carbon concentration was 2.35%, a carbon layer developed on the tungsten surface, and again, no blisters were observed. The effect of target temperature on blister formation was also investigated: the sizes and numbers of the blisters were the largest when the tungsten was irradiated at 653 K; when the sample was irradiated at 388 or 873 K, no blisters larger than 1.0 μm were observed.

The effect of target temperature on the deterioration of metal surfaces under pulsed laser irradiation

The effects of pulsed laser irradiation on preheated solid metal surfaces have been studied. The surface of low-melting point metals (In and Bi) is irradiated by KrF excimer laser pulses of fluences below 400 mJ/cm 2. Evaluation of the optical microscopic pictures of the processed metal surfaces reveals that the characteristic lateral dimension of laser-induced surface structures increases as the melting point is approached. The results are explained in terms of the lifetime of the melt pool, obtained by numerical temperature calculations. Close to the melting point, the increased lifetime of the molten phase allows ample time for smoothing of the surface before its resolidification.

Investigation on Morphology and Microstructure of the SALD SiC

AbstractIn this work, the deposition of silicon carbide lines using a tetramethylsilane (TMS) precursor was investigated. Effects of target temperatures on the morphology and crystal structure of the deposits were examined. It was found that the morphology of the SALD SiC depends strongly on the target temperature. The contour of the cross section of the SiC deposits changes from a triangle to trapezoid to volcano shape and the surface morphology of the deposited lines changes from smooth to rough to porous as the target temperature increases. A critical target temperature was found to be about 700°C to initiate deposition of SiC under the current experimental configurations. X-ray diffraction analyses show that the SALD SiC formed at 1000°C contains both crystalline and amorphous phases. The results are briefly discussed.

Effect of target temperature on the reactive d.c.-sputtering of silicon and niobium oxides

We study the deposition of Si and Nb oxides by reactive d.c.-magnetron sputtering from high temperature metallic Si and Nb targets in Ar/O 2 atmospheres. It is shown that the oxidess formed on Si targets above 1 500 K and on Nb above 2 310 K evaporate, leaving the target surface free of the solid oxide coatings which induce hysteresis, voltage instability and arc breakdown in conventional reactive sputtering. Also, the deposition rate can be much higher because the target surface is coating-free and because sublimed oxides, SiO(g) for Si targets and a mixture of NbO(g) and NbO 2(g) for Nb, contribute significantly to the deposit: The deposition rate of SiO 2 is three times higher than for a conventional process with the same power and for Nb 2O 5, it is seven times higher. Thermionic emission is shown to be an important process which can constitute more than half of the total discharge current in the hot target sputtering of Nb.

Effect of target temperature during nitrogen ion implantation on electrochemical properties of ion-implanted glassy carbon

Abstract The electrochemical properties of glassy carbon (GC) modified by nitrogen ion implantation (a fluence of 1 × 10 16 ions cm − 2 ) at various target temperatures were studied by conventional electrochemical methods. The structure of ion-implanted surface layers of carbon materials has already been investigated by Raman spectroscopy, which has revealed that the implantations at high and low target temperatures produce a graphitic and an amorphous structure respectively. GC implanted at high temperatures (150, 300 and 400°C) showed electrochemical properties resembling those of non-implanted GC as a result of its graphitic structure. In contrast, GC implanted at low temperatures (− 70 and 30°C) forms an electrode surface with an electrochemically inert nature and a low double-layer capacity, which is due to the formation of an amorphous surface layer. A structure of this type is commonly formed by ion implantation into diamond, highly ordered pyrolytic graphite and GC, which has high electrical resistivity and high wear resistance. It was found that the target temperature during ion implantation has a strong effect on the structure and properties of carbon materials. The electrochemically inert and highly wear-resistive carbon formed by low temperature ion implantation will be useful as a superior stable carbon material.

Effects of target temperature on analytical sensitivities of cold-neutron capture prompt gamma-ray activation analysis.

Cold-neutron prompt gamma-ray activation analysis sensitivities are often decreased because of an increase in the average neutron energy on scattering within room temperature targets. Experiments were performed to determine whether target cooling would alleviate these effects. Cooling the targets to 77 K increased hydrogen sensitivity by as much as 25%. Target cooling decreases those effects of neutron scattering on CNPGAA sensitivities that are the result of an increased average neutron energy. However, cold-neutron scattering may also change the average path length traveled, and this effect on sensitivity is not alleviated by controlling temperature.

Effect of target temperature during carbon implantation on the composition and electrochemical properties of iron surface layers

A study was made of the dependence of the properties of iron surface layers on target temperature during carbon implantation. Implantation of C + ions into pure iron sheets was carried out with a dose of 2 × 10 17 ions cm -2 at an energy of 100 keV. The target temperatures during implantation were kept at approximately -100, 20 and 200 °C. The composition and structure of the implanted layers were investigated by X-ray photoelectron spectroscopy, X-ray diffraction and laser Raman spectroscopy. Multisweep cyclic voltammetry was utilized to evaluate the anodic dissolution properties of carbon-implanted iron electrodes. The carbon distribution for specimens implanted at -100 and 20 °C shows a gaussian-like shape except near the top-surface, and the distribution for implantation at 200 °C is trapezoidal. The carbon atoms in the implanted layers combine with iron and carbon itself to form C-Fe and C-C bonds. The higher temperature during implantation produces a larger amount of C-Fe bonds, and in contrast, the lower temperature implantation results in the formation of a larger amount of C-C bonds. The implanted iron electrode at a target temperature of -100 °C shows strong suppression of the anodic dissolution of iron. The relations between the electrochemical properties and surface microscopic characteristics are discussed.

Effects of target temperature on crystallinity and hardness of B+-implanted Fe

Pure Fe is implanted with B+ in a target temperature range of −20–300 °C. The effects of the target temperature on the crystallinity and hardness of the B+ -implanted Fe are investigated. It is found that Fe2 B is formed by using direct B+ implantation into pure Fe at target temperatures ranging from −20 to 300 °C without subsequent annealing. ‘‘Cold-implantation,’’ i.e., implantation at a lower target temperature, reduces crystallinity and increases the hardness of the B+ -implanted Fe. By contrast, increased target temperature produces B+ -implanted Fe with high crystallinity and relatively low hardness. Discussion focuses on how the target temperature during implantation affects the crystallinity of the B+ -implanted Fe from the standpoint of the recrystallization during implantation.

Ｔｉへの酸素イオン注入によるルチルＴｉＯ２形成およびその注入温度依存性

Ｔｉへの酸素イオン注入によるルチルＴｉＯ２形成およびその注入温度依存性

Implantation Profiles of Low-Energy Helium in Silicon Carbide

The projected range profiles of helium implanted in silicon carbide were measured for energies between 1 keV and 20 keV using a method based on a combination of ion sputtering and gas release. The method is capable of producing helium depth profiles with a depth resolution of less than 100 Å, and a sensitivity to implantation fluences of 2×1016 ions/cm2 and below, where bubble formation is unlikely. The results were compared with theoretical predictions by Monte Carlo calculations, and good agreement was obtained by using values of the electronic stopping powers equal to 1.3 times the stopping constants given in the semiempirical tabulation by Northcliffe and Schilling. The effects of target temperature on the helium range profiles were also measured at 600°C, and the results were found to be associated with the grain-boundary diffusion of helium.

Erosion of metals by flyash particles

The erosion of metal targets by flyash from power station electrostatic precipitators was investigated using a novel test rig. Targets of BG303 stainless steel and HE30 aluminium were used. The effects of target temperature and angle of impingement were studied. The size of particles used was less than 66 μm. The rig utilizes a tube with a fine bore to accelerate particles borne by an air flow; the air flow is then separated from the particle stream with a simple Coanda effect attachment on the end of the tube. The targets are heated indirectly with a high resistance heater element. Target temperatures up to 750 °C were attained. The observed erosion characteristics are consistent with previous work. For stainless steel, the erosion rate increases with increasing temperature above 400 °C. For aluminium the erosion rate reaches a maximum value at approximately 300 °C.