Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “DAMAGE”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Damage modeling of power tower receiver tubes using the SRLIFE tool

Concentrating Solar Power (CSP) molten-salt central receivers are subject to high, transient incident flux during daily operation. The resulting creep-fatigue damage impacts the receiver’s reliability and restricts the permissible incident flux distribution for a given receiver. This paper aims to reduce CSP plants’ levelized cost of electricity by developing a methodology to predict lifetime and identifies the primary damage mechanism (creep vs fatigue) for any given fluid temperature and temperature gradient. Results are presented in the form of a damage map that serves as a valuable operation guide and design tool. Damage maps can be used to reduce maintenance costs by improving reliability and reduce receiver capital costs by better utilizing the receiver area. FEA simulation and damage modeling of tubes subject to asymmetrical flux conditions is performed in the open-source receiver design tool srlife. Parametric studies are performed over a range of inner tube temperatures and thermal gradients for A230, 316H, 740H, A282, A617, and 800H high temperature alloys. Damage maps are presented for each alloy. A parametric, FEA-based methodology is presented for comparison of fatigue-creep ratios and prediction of tube lifetime based on the critical thermal operating conditions. Fatigue is found to be negligible compared to creep for almost every case. Here, this finding suggests that fatigue effects associated with cloud events are insignificant compared to creep at these high temperature operating conditions. Additionally, lifetime predictions identify thermal conditions where small changes in operating conditions can result in large changes in predicted lifetime.

14 SOLAR ENERGY↗
DOE OSTI2015

Polychlorinated biphenyl quinone induces oxidative DNA damage and repair responses: The activations of NHEJ, BER and NER via ATM-p53 signaling axis

Our previous studies demonstrated that polychlorinated biphenyl (PCB) quinone induced oxidative DNA damage in HepG2 cells. To promote genomic integrity, DNA damage response (DDR) coordinates cell-cycle transitions, DNA repair and apoptosis. PCB quinone-induced cell cycle arrest and apoptosis have been documented, however, whether PCB quinone insult induce DNA repair signaling is still unknown. In this study, we identified the activation of DDR and corresponding signaling events in HepG2 cells upon the exposure to a synthetic PCB quinone, PCB29-pQ. Our data illustrated that PCB29-pQ induces the phosphorylation of p53, which was mediated by ataxia telangiectasia mutated (ATM) protein kinase. The observed phosphorylated histone H2AX (γ-H2AX) foci and the elevation of 8-hydroxy-2′-deoxyguanosine (8-OHdG) indicated that DDR was stimulated by PCB29-pQ treatment. Additionally, we found PCB29-pQ activates non-homologous end joining (NHEJ), base excision repair (BER) and nucleotide excision repair (NER) signalings. However, these repair pathways are not error-free processes and aberrant repair of DNA damage may cause the potential risk of carcinogenesis and mutagenesis. - Highlights: • Polychlorinated biphenyl quinone induces oxidative DNA damage in HepG2 cells. • The elevation of γ-H2AX and 8-OHdG indicates the activation of DNA damage response. • ATM-p53 signaling acts as the DNA damage sensor and effector. • Polychlorinated biphenyl quinone activates NHEJ, BER and NER signalings.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

Origin and Suppression of Beam Damage-Induced Oxygen-K Edge Artifact from γ-Al 2 O 3 using Cryo-EELS

Gamma-alumina (γ-Al 2 O 3 ), like other low-Z oxides, is readily damaged when exposed to an electron beam. This typically results in the formation of a characteristic pre-edge peak in the oxygen-K edge of electron energy-loss spectra (EELS) acquired during or after the damage process. This artifact can mask the presence of intrinsic O-K edge fine structure that would reveal chemical properties of the material; therefore, its suppression is key. In this work, we systematically investigate the conditions that give rise to the damage-induced O-K pre-edge peak and show that it can be effectively suppressed by performing EELS experiments at cryogenic (cryo) temperatures. Prolonged exposure of γ-Al 2 O 3 to a focused electron beam results in a hole bored through the sample; this was used as a reproducible beam damage condition. O-K edge EELS spectra were collected from a single-crystal γ-Al 2 O 3 sample both during and after focused 2 electron beam hole drilling, and at room and cryo temperatures, using a monochromated scanning transmission electron microscope (STEM). Furthermore, the characteristic 531 eV pre-edge peak visible in the room temperature EELS spectra was completely suppressed in the cryo-EELS spectra, even in the presence of a visible drilled hole. We then correlated these experimental observations with multiple-scattering EELS simulations to determine the likely atomistic origin of the damage-induced O-K pre-edge peak. The findings indicate that the pre-edge peak is caused primarily by the presence of surface O dimer (O-O) bonds formed during beam damage, and that operating at cryo temperature suppresses the formation of surface O-O bonds, thus preventing formation of the O-K pre-edge peak. Additionally, Al-L 2,3 edge EELS spectra revealed Al loss primarily from tetrahedral sites during hole drilling.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2015

The effect of DNA damage on the pattern of immune-detectable DNA methylation in mouse embryonic fibroblasts

The methylation of cytosine at CpG dinucleotides (5meC) is an important epigenetic mechanism that governs genome stability and gene expression. Important ontological and pathological transitions are associated with marked global changes in detectable levels of methylation. We have previously found two pools of immune-detectable 5meC exist within cells, a pool that can be detected after acid treatment of fixed cells to denature chromatin and another large but variable pool that requires a further tryptic digestion step for complete epitope retrieval. The trypsin-sensitive pool has been shown to be largely associated with the heterochromatic fraction (by a heterochromatin marker, HP1-β) of the genome, and the size of this pool varies with the growth disposition of cells. Since DNA damage imposes large changes on chromatin structure the present study analyzed how such changes influences the faithful immunological detection of 5meC within mouse embryonic fibroblasts. DNA damage was induced by either UV-irradiation or doxorubicin treatment, each of which resulted in increased levels of immune-detectable 5meC at 24–48 h after treatment. There was a marked trypsin-sensitive pool of 5meC in these cells which was significantly increased after DNA damage. The increased levels of 5meC staining predominantly co-located with heterochromatic foci within nuclei, as assessed by HP1-β staining. The relative amount of masked 5meC after DNA damage was positively associated with increased levels of HP1-β. The methyl binding protein, MBD1, was a less reliable measure of changes in 5meC, with a significant fraction of 5meC not being marked by MBD1. The cyto-epigenetic approaches used here reveal dynamism in the levels and localization of immune-detectable 5meC within the nuclei of fibroblasts in response to DNA damage. - Highlights: • Immune-detectable 5meC within two pools retrieved after acid and trypsin after acid. • The size of the trypsin-sensitive pool varied in response to DNA damage. • This was associated with changes in the level of HP1-β within heterochromatic foci. • Epitope retrieval method detected remarkable dynamism in 5meC's level and location.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Linking loss of sodium-iodide symporter expression to DNA damage

Radiotherapy of thyroid cancer with I-131 is abrogated by inherent loss of radioiodine uptake due to loss of sodium iodide symporter (NIS) expression in poorly differentiated tumor cells. It is also known that ionizing radiation per se down-regulates NIS (the stunning effect), but the mechanism is unknown. Here we investigated whether loss of NIS-mediated iodide transport may be elicited by DNA damage. Calicheamicin, a fungal toxin that specifically cleaves double-stranded DNA, induced a full scale DNA damage response mediated by the ataxia-telangiectasia mutated (ATM) kinase in quiescent normal thyrocytes. At sublethal concentrations (<1 nM) calicheamicin blocked NIS mRNA expression and transepithelial iodide transport as stimulated by thyrotropin; loss of function occurred at a much faster rate than after I-131 irradiation. KU-55933, a selective ATM kinase inhibitor, partly rescued NIS expression and iodide transport in DNA-damaged cells. Prolonged ATM inhibition in healthy cells also repressed NIS-mediated iodide transport. ATM-dependent loss of iodide transport was counteracted by IGF-1. Together, these findings indicate that NIS, the major iodide transporter of the thyroid gland, is susceptible to DNA damage involving ATM-mediated mechanisms. This uncovers novel means of poor radioiodine uptake in thyroid cells subjected to extrinsic or intrinsic genotoxic stress. - Highlights: • DNA damage inhibits polarized iodide transport in normal thyroid cells. • Down-regulation of NIS expression is mediated by activation of the ATM kinase. • Long-term ATM inhibition also represses NIS-mediated iodide transport. • IGF-1 rescues NIS expression and iodide transport in DNA-damaged cells.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2019

Reducing Radiation Damage in Soft Matter with Femtosecond-Timed Single-Electron Packets

In spite of the development of a myriad of mitigation methods, radiation damage continues to be a major limiting factor in transmission electron microscopy. Intriguing results have been reported using pulsed-laser driven and chopped electron beams for modulated dose delivery, but the underlying relationships and effects remain unclear. Indeed, delivering precisely timed single-electron packets to the specimen has yet to be systematically explored, and no direct comparisons to conventional methods within a common parameter space have been made. Here, using a model linear saturated hydrocarbon (n-hexatriacontane, C 36 H 74 ), we show that precisely timed delivery of each electron to the specimen, with a well-defined and uniform time between arrival, leads to a repeatable reduction in damage compared to conventional ultralow-dose methods for the same dose rate and the same accumulated dose. Using a femtosecond pulsed laser to confine the probability of electron emission to a 300 fs temporal window, we find damage to be sensitively dependent on the time between electron arrival (controlled with the laser repetition rate) and on the number of electrons per packet (controlled with the laser-pulse energy). Relative arrival times of 5, 20, and 100 μs were tested for electron packets comprised of, on average, 1, 5, and 20 electrons. In general, damage increased with decreasing time between electrons and, more substantially, with increasing electron number. Further, we find that improvements relative to conventional methods vanish once a threshold number of electrons per packet is reached. The results indicate that precise electron-by-electron dose delivery leads to a repeatable reduction in irreversible structural damage, and the systematic studies indicate this arises from control of the time between sequential electrons arriving within the same damage radius, all else being equal.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Atomistic simulation of damage accumulation and amorphization in Ge

Damage accumulation and amorphization mechanisms by means of ion implantation in Ge are studied using Kinetic Monte Carlo and Binary Collision Approximation techniques. Such mechanisms are investigated through different stages of damage accumulation taking place in the implantation process: from point defect generation and cluster formation up to full amorphization of Ge layers. We propose a damage concentration amorphization threshold for Ge of ∼1.3 × 10{sup 22} cm{sup −3} which is independent on the implantation conditions. Recombination energy barriers depending on amorphous pocket sizes are provided. This leads to an explanation of the reported distinct behavior of the damage generated by different ions. We have also observed that the dissolution of clusters plays an important role for relatively high temperatures and fluences. The model is able to explain and predict different damage generation regimes, amount of generated damage, and extension of amorphous layers in Ge for different ions and implantation conditions.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Unified continuum damage model for matrix cracking in composite rotor blades

This paper deals with modeling of the first damage mode, matrix micro-cracking, in helicopter rotor/wind turbine blades and how this effects the overall cross-sectional stiffness. The helicopter/wind turbine rotor system operates in a highly dynamic and unsteady environment leading to severe vibratory loads present in the system. Repeated exposure to this loading condition can induce damage in the composite rotor blades. These rotor/turbine blades are generally made of fiber-reinforced laminated composites and exhibit various competing modes of damage such as matrix micro-cracking, delamination, and fiber breakage. There is a need to study the behavior of the composite rotor system under various key damage modes in composite materials for developing Structural Health Monitoring (SHM) system. Each blade is modeled as a beam based on geometrically non-linear 3-D elasticity theory. Each blade thus splits into 2-D analyzes of cross-sections and non-linear 1-D analyzes along the beam reference curves. Two different tools are used here for complete 3-D analysis: VABS for 2-D cross-sectional analysis and GEBT for 1-D beam analysis. The physically-based failure models for matrix in compression and tension loading are used in the present work. Matrix cracking is detected using two failure criterion: Matrix Failure in Compression and Matrix Failure in Tension which are based on the recovered field. A strain variable is set which drives the damage variable for matrix cracking and this damage variable is used to estimate the reduced cross-sectional stiffness. The matrix micro-cracking is performed in two different approaches: (i) Element-wise, and (ii) Node-wise. The procedure presented in this paper is implemented in VABS as matrix micro-cracking modeling module. Three examples are presented to investigate the matrix failure model which illustrate the effect of matrix cracking on cross-sectional stiffness by varying the applied cyclic load.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Active investigation of material damage under load using micro-CT

Due the growth of composite materials across multiple industries such as Aviation, Wind there is an increasing need to not just standardize and improve manufacturing processes but also to design these materials for the specific applications. One of the things that this translates to is understanding how failure initiates and grows in these materials and at what loads, especially around internal flaws such as voids or features such as ply drops. Traditional methods of investigating internal damage such as CT lack the resolution to resolve ply level damage in composites. Interrupted testing with layer removal can be used to investigate internal damage using microscopy; however this is a destructive method. Advanced techniques such as such as DIC are useful for in-situ damage detection, however are limited to surface information and would not enable interrogating the volume. Computed tomography has become a state of the art technique for metrology and complete volumetric investigation especially for metallic components. However, its application to the composite world is still nascent. This paper demonstrates micro-CT’s capability as a gauge to quantitatively estimate the extent of damage and understand the propagation of damage in PMC composites while the component is under stress.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Damage mapping in structural health monitoring using a multi-grid architecture

This paper presents a multi-grid architecture for tomography-based damage mapping of composite aerospace structures. The system employs an array of piezo-electric transducers bonded on the structure. Each transducer may be used as an actuator as well as a sensor. The structure is excited sequentially using the actuators and the guided waves arriving at the sensors in response to the excitations are recorded for further analysis. The sensor signals are compared to their baseline counterparts and a damage index is computed for each actuator-sensor pair. These damage indices are then used as inputs to the tomographic reconstruction system. Preliminary damage maps are reconstructed on multiple coordinate grids defined on the structure. These grids are shifted versions of each other where the shift is a fraction of the spatial sampling interval associated with each grid. These preliminary damage maps are then combined to provide a reconstruction that is more robust to measurement noise in the sensor signals and the ill-conditioned problem formulation for single-grid algorithms. Experimental results on a composite structure with complexity that is representative of aerospace structures included in the paper demonstrate that for sufficiently high sensor densities, the algorithm of this paper is capable of providing damage detection and characterization with accuracy comparable to traditional C-scan and A-scan-based ultrasound non-destructive inspection systems quickly and without human supervision.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Nonlinear ultrasonic assessment of stress corrosion cracking damage in sensitized 304 stainless steel

This research uses nonlinear Rayleigh surface waves to characterize stress corrosion cracking (SCC) damage in welded 304 Stainless Steel (304 SS). 304 SS is widely used in reactor pressure vessels, where a corrosive environment in combination with applied stress due to high internal pressures can cause SCC. Welds and the nearby heat affected zones (HAZ) in the vessel material are especially sensitive to SCC damage. SCC damage results in microstructural changes such as dislocation formation and microcrack initiation that in the long term lead to reduced structural integrity and material failure. Therefore, the early detection of SCC is crucial to ensure safe operation. It has been shown that the microstructural changes caused by SCC can generate higher harmonic waves when excited harmonically. This research considers different levels of SCC damage induced in samples of welded 304 SS by applying stress to a specimen held in a corrosive medium (Sodium Thiosulfate). A nonlinear Rayleigh surface wave is introduced in the material and the fundamental and the second harmonic waves are measured using wedge detection. The nonlinearity parameter that relates the fundamental and the second harmonic amplitudes, is computed to quantify the SCC damage in each sample. These results are used to demonstrate the feasibility of using nonlinear Rayleigh waves to characterize SCC damage.

42 ENGINEERING↗
DOE OSTI2015

The efficacy of post porosity plasma protection against vacuum-ultraviolet damage in porous low-k materials

As of today, plasma damage remains as one of the main challenges to the reliable integration of porous low-k materials into microelectronic devices at the most aggressive node. One promising strategy to limit damage of porous low-k materials during plasma processing is an approach we refer to as post porosity plasma protection (P4). In this approach, the pores of the low-k material are filled with a sacrificial agent prior to any plasma treatment, greatly minimizing the total damage by limiting the physical interactions between plasma species and the low-k material. Interestingly, the contribution of the individual plasma species to the total plasma damage is not fully understood. In this study, we investigated the specific damaging effect of vacuum-ultraviolet (v-UV) photons on a highly porous, k = 2.0 low-k material and we assessed the P4 protective effect against them. It was found that the impact of the v-UV radiation varied depending upon the v-UV emission lines of the plasma. More importantly, we successfully demonstrated that the P4 process provides excellent protection against v-UV damage.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Lateral damage in graphene carved by high energy focused gallium ion beams

Raman mapping is performed to study the lateral damage in supported monolayer graphene carved by 30 keV focused Ga{sup +} beams. The evolution of the lateral damage is tracked based on the profiles of the intensity ratio between the D (1341 cm{sup −1}) and G (1582 cm{sup −1}) peaks (I{sub D}/I{sub G}) of the Raman spectra. The I{sub D}/I{sub G} profile clearly reveals the transition from stage 2 disorder into stage 1 disorder in graphene along the direction away from the carved area. The critical lateral damage distance spans from <1 μm up to more than 30 μm in the experiment, depending on the parameters used for carving the graphene. The wide damage in the lateral direction is attributed to the deleterious tail of unfocused ions in the ion beam probe. The study raises the attention on potential sample damage during direct patterning of graphene nanostructures using the focused ion beam technique. Minimizing the total carving time is recommended to mitigate the lateral damage.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Direct comparison of defect ensembles extracted from damage probability and raster scan measurements

The presented study addresses the characterization of nanometer sized defects acting as damage precursors in nanosecond laser pulse duration regime. Two approaches are used to extract distributions of localized damage precursors, namely, damage probability and damage density measurements. Testing is performed on uncoated and SiO{sub 2} monolayer film deposited fused silica substrate exposed with pulsed UV irradiation (355 nm, 4.8 ns). Then, a direct comparison of damage precursor ensembles obtained from both methods is carried out. Our analysis indicates apparent differences between both methods that are discussed in detail. Contamination by ablation products is identified as one of the key factors that influence damage density measurements.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Irreversible entropy model for damage diagnosis in resistors

We propose a method to characterize electrical resistor damage based on entropy measurements. Irreversible entropy and the rate at which it is generated are more convenient parameters than resistance for describing damage because they are essentially positive in virtue of the second law of thermodynamics, whereas resistance may increase or decrease depending on the degradation mechanism. Commercial resistors were tested in order to characterize the damage induced by power surges. Resistors were biased with constant and pulsed voltage signals, leading to power dissipation in the range of 4–8 W, which is well above the 0.25 W nominal power to initiate failure. Entropy was inferred from the added power and temperature evolution. A model is proposed to understand the relationship among resistance, entropy, and damage. The power surge dissipates into heat (Joule effect) and damages the resistor. The results show a correlation between entropy generation rate and resistor failure. We conclude that damage can be conveniently assessed from irreversible entropy generation. Our results for resistors can be easily extrapolated to other systems or machines that can be modeled based on their resistance.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2019

Low energy secondary electron induced damage of condensed nucleotides

Radiation damage and stimulated desorption of nucleotides 2'-deoxyadenosine 5'-monophosphate (dAMP), adenosine 5'-monophosphate (rAMP), 2'-deoxycytidine 5'-monophosphate (dCMP), and cytidine 5'-monophosphate (rCMP) deposited on Au have been measured using x-rays as both the probe and source of low energy secondary electrons. The fluence dependent behavior of the O-1s, C-1s, and N-1s photoelectron transitions was analyzed to obtain phosphate, sugar, and nucleobase damage cross sections. Although x-ray induced reactions in nucleotides involve both direct ionization and excitation, the observed bonding changes were likely dominated by the inelastic energy-loss channels associated with secondary electron capture and transient negative ion decay. Growth of the integrated peak area for the O-1s component at 531.3 eV, corresponding to cleavage of the C—O—P phosphodiester bond, yielded effective damage cross sections of about 23 Mb and 32 Mb (1 Mb = 10 –18 cm 2 ) for AMP and CMP molecules, respectively. The cross sections for sugar damage, as determined from the decay of the C-1s component at 286.4 eV and the glycosidic carbon at 289.0 eV, were slightly lower (about 20 Mb) and statistically similar for the r- and d- forms of the nucleotides. Here, the C-1s component at 287.6 eV, corresponding to carbons in the nucleobase ring, showed a small initial increase and then decayed slowly, yielding a low damage cross section (~5 Mb). Although there is no statistical difference between the sugar forms, changing the nucleobase from adenine to cytidine has a slight effect on the damage cross section, possibly due to differing electron capture and transfer probabilities.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2016

Role of HfO 2 /SiO 2 thin-film interfaces in near-ultraviolet absorption and pulsed laser damage

Here, the role of thin-film interfaces in the near-ultraviolet (near-UV) absorption and pulsed laser-induced damage was studied for ion-beam-sputtered and electron-beam-evaporated coatings comprised from HfO 2 and SiO 2 thin-film pairs. To separate contributions from the bulk of the film and from interfacial areas, absorption and damage threshold measurements were performed for a one-wave (355-nm wavelength) thick, HfO 2 single-layer film and for a film containing seven narrow HfO 2 layers separated by SiO 2 layers. The seven-layer film was designed to have a total optical thickness of HfO 2 layers, equal to one wave at 355 nm and an E-field peak and average intensity similar to a single-layer HfO 2 film. Absorption in both types of films was measured using laser calorimetry and photothermal heterodyne imaging. The results showed a small contribution to total absorption from thin-film interfaces as compared to HfO 2 film material. The relevance of obtained absorption data to coating near-UV, nanosecond-pulse laser damage was verified by measuring the damage threshold and characterizing damage morphology. The results of this study revealed a higher damage resistance in the seven-layer coating as compared to the single-layer HfO 2 film in both sputtered and evaporated coatings. The results are explained through the similarity of interfacial film structure with structure formed during the codeposition of HfO 2 and SiO 2 materials.

36 MATERIALS SCIENCE↗
DOE OSTI2015

The role of film interfaces in near-ultraviolet absorption and pulsed-laser damage in ion-beam-sputtered coatings based on HfO 2 /SiO 2 thin-film pairs

The role of thin-film interfaces in the near-ultraviolet absorption and pulsed-laser–induced damage was studied for ion-beam–sputtered and electron-beam–evaporated coatings comprised from HfO 2 and SiO 2 thin-film pairs. To separate contributions from the bulk of the film and from interfacial areas, absorption and damage-threshold measurements were performed for a one-wave (355-nm wavelength) thick, HfO 2 single-layer film and for a film containing seven narrow HfO 2 layers separated by SiO 2 layers. The seven-layer film was designed to have a total optical thickness of HfO 2 layers, equal to one wave at 355 nm and an E-field peak and average intensity similar to a single-layer HfO 2 film. Absorption in both types of films was measured using laser calorimetry and photothermal heterodyne imaging. The results showed a small contribution to total absorption from thin-film interfaces, as compared to HfO 2 film material. The relevance of obtained absorption data to coating near-ultraviolet, nanosecond-pulse laser damage was verified by measuring the damage threshold and characterizing damage morphology. The results of this study revealed a higher damage resistance in the seven-layer coating as compared to the single-layer HfO 2 film in both sputtered and evaporated coatings. Here, the results are explained through the similarity of interfacial film structure with structure formed during the co-deposition of HfO 2 and SiO 2 materials.

36 MATERIALS SCIENCE↗