Diffraction Transmission Electron Research Articles

First-principles calculations of quartz–coesite interfaces

Atomistic interface structures compatible with periodic boundary conditions for the strain-induced subsolidus martensitic transition between quartz and coesite have been investigated. We identified layers of atoms that remained unchanged in terms of neighbor interactions throughout the transformation. Our analysis revealed that the orientation relationships between quartz and coesite, namely (1011)Qz||(010)Coe and (1321)Qz||(010)Coe, are consistent with experimental observations. Using density-functional-theory-based tight-binding model calculations, we determined an interface energy of approximately 660 mJ m−2 for these interfaces and strain energies of 196 (6) and 2760 (160) J mol−1 atom−1 for the (1321)Qz||(010)Coe and (1011)Qz||(010)Coe oriented interfaces, respectively. To visualize these interface structures and facilitate their identification in experiments, we simulated high-resolution transmission electron microscopy images and electron diffraction patterns.

Comparative electron diffraction analysis of strain relaxation in AlxGa1-xN materials in the microelectronics industry: 4D-STEM approach vs. TEM-based N-PED solution.

Owing to its high spatial resolution and its high sensitivity to chemical element detection, transmission electron microscopy (TEM) technique enables to address high-level materials characterization of advanced technologies in the microelectronics field. TEM instruments fitted with various techniques are well-suited for assessing the local structural and chemical order of specific details. Among these techniques, 4D-STEM is suitable to estimate the strain distribution of a large field of view. This study tends to discuss the viability of using two existing commercial solutions with a low-convergence angle 4D-STEM technique and TEM-based Nanobeam Precession Electron Diffraction (N-PED) methods for strain analysis in an industrial context. In such a framework, strain measurements intend to point out the extent of defects and thus reveal a trend of the stress field, rather than to precisely estimate the absolute values of the deformations. Strain distribution maps have been obtained for AlGaN/GaN HEMT devices using two transmission electron diffraction analysis methods. The performances of 4D-STEM and Nanobeam Precession Electron Diffraction (N-PED) solution for strain mapping have been compared for both a relatively thin (≈ 55 nm) and a thick (≈ 150 nm) TEM cross section specimen. The strain maps obtained with both methods have shown comparable results for a thin sample, with the ability to characterize the deformation induced by a 1 nm-thick layer of AlN spacer grown between the AlGaN barrier and GaN channel forming the 2DEG of the HEMT device. The results presented here also illustrate the limitation of both commercial solutions in the case of a thick sample.

Reinterpretation of Report of Tetrataenite in Bulk Alloy Castings.

After the publication of "Direct formation of hard-magnetic tetrataenite in bulk alloy castings" Ivanov etal., Advanced Science 10 (2022) 2204315, the authors identified a potential misinterpretation of the experimental data. Further work confirms that the original conclusions cannot be supported, and accordingly the paper is retracted. X-ray diffraction shows the presence of (Fe,Ni)3P, giving additional Bragg peaks that were previously attributed to tetrataenite. Extra Bragg reflections observed in transmission electron diffraction, and earlier considered to be superlattice reflections from tetrataenite, instead result from oxidation of the sample surface during preparation. Measurements of magnetic hysteresis show no regions of high coercivity of the kind expected when tetrataenite is present. It is concluded that as-cast bulk samples of Fe-Ni-P-(C) show no evidence of tetrataenite on any length scale. Nevertheless, the addition of phosphorus should remain of interest in ongoing efforts to manufacture tetrataenite.

Iridium-Doped Manganese Oxide Nanosheets with Enhanced Pseudocapacitive Properties

Atomically thin inorganic oxides, called nanosheets, are attractive electrode materials especially for electrochemical supercapacitors because of their large surface area and tunable composition. Birnessite-type manganese oxide nanosheets are one of the promising candidates because they possess pseudocapacitance associated with fast redox process in neutral electrolytes and electrochemical stability at wide potential range. One of the significant drawbacks for manganese oxide nanosheets-based capacitive electrodes is its poor conductivity. Doping manganese oxides with other transition metals is known as an effective method to increase the electronic conductivity as well as the specific capacitance.1–2 We have reported the preparation of a new solid solution, iridium-doped birnessite-type manganese oxide K-(Mn1–x Ir x )O2 (x = 0, 0.05, 0.1).3 Interestingly, K-(Mn1–x Ir x )O2 exhibits enhanced redox-related pseudocapacitance in aqueous Li2SO4 with unusual Mn4+/Mn3+ redox where the peak-to-peak potential difference decreased with increasing the amount of doped Ir. Here, we report successful exfoliation into iridium-doped manganese oxide nanosheets ((Mn1–x Ir x )O2(ns)) and its charge storage capabilities. The parent layered oxide, K-(Mn0.9Ir0.1)O2, was prepared by coprecipitation method according to literature.3 After proton exchange of K-(Mn0.9Ir0.1)O2 and subsequent shaking in an aqueous tetrabutylammonium hydroxide solution, colloidal dispersion with a dark-green color was formed. Transmission electron microscopy and electron diffraction revealed the formation of crystalline nanosheets with the lateral size of several hundreds of nanometers. UV-vis spectrum of the dispersion of (Mn0.9Ir0.1)O2(ns) shows absorption peak at around 365 nm, which is blue-shifted from that at around 380 nm of non-doped MnO2(ns). These results indicate that the exfoliation of K-(Mn0.9Ir0.1)O2 successfully proceeded while preserving the iridium in the manganese oxide framework. For electrochemical measurements, (Mn0.9Ir0.1)O2(ns) was composited with acetylene black (AB) as a conductive binder and the mixture was casted onto a glassy carbon electrode. Cyclic voltammetry in 1.0 M Li2SO4 in the potential range of 0.6–1.2 V versus RHE shows the broadened but large redox currents associated with the Mn4+/Mn3+ redox reaction. The specific capacitance of (Mn0.9Ir0.1)O2(ns)/AB at various scan rates is larger than that of MnO2(ns)/AB and less dependent on the scan rates. These changes are probably due to an improvement in the charge-transfer process of the Mn4+/Mn3+ redox, which indicate that the strong electronic interaction between Mn and Ir was preserved even after exfoliation.(1) S.-J. Kim, I.Y. Kim, S.B. Patil, S.M. Oh, N.-S. Lee, S.-J. Hwang, Chem. Eur. J., 2014, 20, 5132. (2) M. Nakayama, K. Suzuki, K. Okamura, R. Inoue, L. Athouël, O. Crosnier, and T. Brousse, J. Electrochem. Soc., 2010, 157, A1067. (3) R. Saito, H. Tanaka, K. Teshima, D. Takimoto, S. Hideshima, and W. Sugimoto, Inorg. Chem., 2022, 61, 4566.

Recrystallization of amorphous AlNbCr coatings irradiated with chromium ions

Applying an AlNbCr layer on the surface of Zr alloys significantly enhances the alloy resistance to oxidation and high-temperature corrosion. However, the effects of irradiation on AlNbCr coating remain largely unexplored. This work investigates the microstructural evolution of Cr ion-irradiated AlNbCr coatings under varying temperatures, utilizing bright-field transmission electron microscopy (TEM) observations and electron diffraction pattern analyses. With increasing Cr ion irradiation dose, the coatings gradually transitioned from an initial amorphous to a crystalline state. The onset of crystallization occurred earlier at higher temperatures, indicating that the crystallization process was significantly influenced by temperature. Moreover, the dynamic crystallization process of the crystalline structure was also analyzed, as well as the different irradiation responses at the Near-Interface Area (NIA) and Far-Interface Area (FIA). These findings provide new insights for understanding and optimizing the performance of AlNbCr coatings in high-irradiation environments.

Synthesis, Structural, Morphological, and Optical Properties of Promising Lead-Free Double Perovskite Na2CuBiBr6: A Sustainable Material for Photovoltaic Applications

This work primarily focuses on synthesizing and evaluating the structure, morphology, and optical features of double perovskite Na2CuBiBr6 forphotovoltaic devices. In the present investigation, Na2CuBiBr6 is created by a solution-based antisolvent recrystallization approach. A comprehensive experimental investigation is conducted on the Na2CuBiBr6 double perovskite, encompassing its structural configuration, morphology, and optical features. X-ray diffraction analysis verifies the creation of Na2CuBiBr6 double perovskite and showcases its exceptional phasestability in the cubic phase. Scanning electron microscopy reveals the presence of multidirectional crystals ofNa2CuBiBr6crystals. The presence of polycrystalline cubic Na2CuBiBr6 is confirmed using transmission electron microscopy and electron diffraction investigation. In addition, energy-dispersive X-ray spectroscopy demonstrates the consistent distribution of elements within Na2CuBiBr6. UV–vis spectroscopy reveals a band gap of 1.37 eV. The optical characteristics demonstrate that Na2CuBiBr6 exhibits a greater absorbance level and a lower reflectivity level within the visible spectrum. The results of this study suggest that the Na2CuBiBr6 double perovskite, which is both lead-free and environmentally benign, has significant potential for applications in photovoltaic and thermoelectric devices.

Preparation of Coir Cellulose Nanofibers by Peroxyformic Acid Method and Their Application in Reinforced PVA Composite Films.

To increase the value of waste coconut shells and further broaden their use by biorefining, a milder and greener method to prepare cellulose nanofibers (CCNFs) was developed. The CCNFs were separated from coir fibers by using peroxyformic acid and alkali treatment in combination with high-power ultrasonication. The basic properties of the CCNFs were comprehensively evaluated using scanning and transmission electron microscopy, spectroscopy, diffraction, and thermogravimetric techniques. The results revealed that the developed preparation method provided CCNFs with typical nanocellulose sizes, structures, and properties. Nanocellulose-reinforced poly(vinyl acetate) (PVA) composite films were prepared using the CCNFs, and their mechanical properties, transmittance, crystallinity, and thermal stability were investigated. The elongation at break of the film with 8% CCNFs was 612%. The tensile strength of the films with 4 and 12% CCNFs was 41.3 MPa, which was higher than that of a PVA film (36 MPa). The transmittance and thermal stability of the PVA composite films were not appreciably affected by the CCNFs. The CCNFs show promise as a nanofiller for PVA-based composite films with favorable mechanical properties, crystallinity, and high transparency.

Transmission Electron Imaging and Diffraction of Asbestos Fibers in an SEM

Transmission Electron Imaging and Diffraction of Asbestos Fibers in an SEM

Experimental determination and thermodynamic reassessment of the Al–Cr–Ru ternary system

The isothermal sections at 950 °C and 1150 °C of Al–Cr–Ru ternary system were determined experimentally by equilibrium alloy method, combined with X-ray diffraction, scanning electron microscopy and energy-dispersive spectrometric. Nine and eight three-phase equilibria were confirmed at the 950 °C and 1150 °C isothermal sections of the Al–Cr–Ru ternary systems, respectively. The liquids surface projection of the Al–Cr–Ru ternary system was determined by identifying the microstructures of the as-cast alloys, and seven primary solidification regions were determined in the liquids surface projection. Besides, the ternary compound τ2 was identified as end-centered monoclinic structure by transmission electron diffraction analysis. The lattice parameters of the τ2 phase are a = 0.5175 nm, b = 1.7532 nm, c = 0.5150 nm and α = γ = 90°, β = 79.167°. Based on the available data of the Al–Cr–Ru ternary system and related binary systems, thermodynamic reassessment of the Al–Cr–Ru ternary system was performed using the Calculation of Phase Diagram approach. A new thermodynamic database for the Al–Cr–Ru ternary system was obtained, and the experimental data are consistent well with the calculated results.

Metallographic and Extraction Replica Methods for Characterization of Tungsten Heavy Alloy: H13 Clads

Tungsten heavy alloys are used in demanding high pressure die casting applications due to their high temperature strength, high thermal conductivity, and low thermal expansion. High cost limits applications to small sintered die inserts and manual gas tungsten arc weld repairs. A new tungsten heavy alloy consumable, Anviloy wire, was developed for automated cladding of hot work tool steel dies. Literature regarding characterization of tungsten heavy alloy die steel clads was lacking. Understanding base metal dilution effect on clad microstructure is critical but required new sample preparation methods. An Anviloy wire-H13 clad was made using hot wire gas tungsten arc cladding and analyzed with metallography. Samples were found to have grain boundary M6C carbide phase as-welded with the help of an alkaline sodium picrate etchant. An isothermally aged arc crucible melted sample of the same composition was characterized using metallography, scanning electron microscopy, and transmission electron diffraction. The clad representative arc crucible melted sample was subjected to isothermal aging at 725°C for 100 hours. Isothermal aging resulted in precipitation of a high volume fraction of intermetallic platelets. Using a new carbon extraction replica sample preparation method involving two chemical polishing steps, transmission electron diffraction of precipitates indicated they were mu phase intermetallic.

Investigation of the structural stability of polycrystalline cBN under near-industrial grinding process conditions

Cubic boron nitride (cBN) is an important material in the cutting and metal processing industries due to its exceptional hardness and high thermal stability, which allows it to withstand temperatures up to 1400 °C without decomposing. These properties make cBN and, with that, polycrystalline cBN (PcBN) ideal materials for high-speed machining and other applications, resulting in increased efficiency and reduced costs in production processes. Despite its established importance, the possibility of phase transformations into hexagonal boron nitride phases or partial amorphization during industrial PcBN grinding processes remains unclear and, due to the deteriorated mechanical characteristics, raised recently some concerns about possible losses of cBN's hardness, wear resistance, and abrasive properties. In order to address this issue and for identifying such potential structural changes, a commercial PcBN grade was exposed to near-industrial grinding process conditions and then characterized in detail by conventional (scanning) transmission electron microscopy (S)TEM and (scanning) electron diffraction techniques. To understand the influence of the PcBN machining on the material, the grinding process also needs to be assessed via the identification of chip formation mechanisms, which is as well addressed in this work. The main outcome of this study, combining a material analysis and a manufacturing technology point of view, is that there is so far no evidence of any structural instabilities of PcBN under usual processing conditions.

Spherical and porous Cu2O nanocages with Cu2O/Cu(OH)2 Surface: Synthesis and their promising selectivity for catalysing CO2 electroreduction to C2H4

In the production of C2H4, a vital raw material in the synthesis of polyethylene and polyvinyl chloride, Cu2O is a highly promising catalyst with excellent Faradaic efficiency and selectivity. We propose a method involving the partial reduction of Cu(OH)2 to Cu2O by sodium L-ascorbate for the synthesis of spherical and porous Cu2O nanocages (SPNCs) with a surface containing both Cu2O and Cu(OH)2. High-resolution transmission electron microscopy and electron diffraction measurements revealed ∼ 3-nm pores and a (13¯2) high-index facet on the SPNC, respectively. As SPNCs have a porous structure, their specific surface area is greater (31.10 m2 g−1) than that (6.35 m2 g−1) of spherical Cu2O nanocrystals (SNCs) with solid interiors. Furthermore, SPNCs, when applied as electrocatalysts for catalysing the CO2 reduction reaction (CO2RR), demonstrated remarkable mass activities (16.92 mA mg−1 at −1.15 V vs. reversible hydrogen electrode) for C2H4 production, with a Faraday efficiency reaching an impressive 55.3 %. Stability test data showed a consistent CO2RR current density over 6 h, owing to the porous structure and the presence of both Cu(OH)2 and Cu2O on the catalyst surface. Our proposed SPNC catalysts can be employed as effective CO2RR catalysts for producing C2H4, which may help in reducing the present reliance on petrochemical processes.

Revisiting the Crystallography of {225}γ Martensite: How EBSD Can Help to Solve Long-Standing Controversy

Explaining the crystallography of iron alloys martensite with a {225}γ habit plane remains a challenging task within the phenomenological theory of martensite crystallography. The purpose of this study is to re-examine the martensite formed in a Fe-8Cr-1.1C alloy using EBSD, which has a better angular resolution than the conventional transmission electron diffraction techniques previously used. The results show that the single morphological plates, which hold a near {225}γ habit plane, are bivariant composites made up of two twin-related variants. It is shown that a {113}γ plane is systematically parallel to one of the three common 112α planes between the two twin-related crystals. This observation suggests that the lattice invariant strain of transformation occurs through a dislocation glide on the {113}γ ⟨110⟩γ system, rather than through twinning as is commonly accepted. Based on this assumption, the predictions of Bowles and Mackenzie’s original theory are in good agreement with the crystallographic features of {225}γ martensite. Unexpectedly, it is the high shear solution of the theory that gives the most accurate experimental predictions.

Crystallography and Interface Structures in As-Arc Melted and Laser Surface-Remelted Aluminum–Silicon Alloys with and without Strontium Addition

The crystallography of the eutectic Al-Si microstructure in both unmodified and Sr (0.2 wt.%)-modified hypereutectic Al-20 wt.% Si alloys, processed via arc-melting and laser surface remelting, has been comprehensively characterized using transmission electron microscopy and electron diffraction. Although, under as-cast conditions, specific orientations between different planes of Al and Si, satisfying defined orientation relationships (ORs), have been investigated within the flake morphology, the rapid solidification induced by laser surface remelting results in a notable transformation from a flake morphology to nanocrystalline Si fibers dispersed in an Al matrix. Consequently, this transformation results in a mis-orientation of the interface between the eutectic Al and Si phases, preventing the formation of orientation relationships, thus promoting the formation of faceted interfaces exhibiting substantial lattice disregistry.

Impact of palladium/palladium hydride conversion on electrochemical CO2 reduction via in-situ transmission electron microscopy and diffraction

Electrochemical conversion of CO2 offers a sustainable route for producing fuels and chemicals. Pd-based catalysts are effective for converting CO2 into formate at low overpotentials and CO/H2 at high overpotentials, while undergoing poorly understood morphology and phase structure transformations under reaction conditions that impact performance. Herein, in-situ liquid-phase transmission electron microscopy and select area diffraction measurements are applied to track the morphology and Pd/PdHx phase interconversion under reaction conditions as a function of electrode potential. These studies identify the degradation mechanisms, including poisoning and physical structure changes, occurring in PdHx/Pd electrodes. Constant potential density functional theory calculations are used to probe the reaction mechanisms occurring on the PdHx structures observed under reaction conditions. Microkinetic modeling reveals that the intercalation of *H into Pd is essential for formate production. However, the change in electrochemical CO2 conversion selectivity away from formate and towards CO/H2 at increasing overpotentials is due to electrode potential dependent changes in the reaction energetics and not a consequence of morphology or phase structure changes.

On-Chip Modification of Titanium Electrothermal Characteristics by Joule Heating: Application to Terahertz Microbolometer.

This study demonstrates the conversion of metallic titanium (Ti) to titanium oxide just by conducting electrical current through Ti thin film in vacuum and increasing the temperature by Joule heating. This led to the improvement of electrical and thermal properties of a microbolometer. A microbolometer with an integrated Ti thermistor and heater width of 2.7 µm and a length of 50 µm was fabricated for the current study. Constant-voltage stresses were applied to the thermistor wire to observe the effect of the Joule heating on its properties. Thermistor resistance ~14 times the initial resistance was observed owing to the heating. A negative large temperature coefficient of resistance (TCR) of -0.32%/K was also observed owing to the treatment, leading to an improved responsivity of ~4.5 times from devices with untreated Ti thermistors. However, this does not improve the noise equivalent power (NEP), due to the increased flicker noise. Microstructural analyses with transmission electron microscopy (TEM), transmission electron diffraction (TED) and energy dispersive X-ray (EDX) confirm the formation of a titanium oxide (TiOx) semiconducting phase on the Ti phase (~85% purity) deposited initially, further to the heating. Formation of TiOx during annealing could minimize the narrow width effect, which we reported previously in thin metal wires, leading to enhancement of responsivity.

Facile Synthesis of Stable Nanosized Silver Clusters in Plasma Discharge Under Ultrasonic Cavitation

This work is devoted to the study of plasma-chemical processes determined by the combination of the effect of thermally nonequilibrium, low-temperature plasma and intensive ultrasonic vibrations in the regime of intensive cavitation on liquid-phase media. This method for the realization of plasma-chemical transformations has been proven to be of significant interest and to have advantages for the creation of new nano-sized materials with special properties because it allows for varying the electrophysical and acoustic characteristics of the process when carrying out plasma-chemical reactions and fusion reactions. In this work, a novel facile technique for the synthesis of nanosized silver clusters in plasma discharge under ultrasonic cavitation is reported. Such a type of plasma involves the simultaneous effect of high-intensity cavitation and steady electric discharge in a liquid phase between electrodes of desired material. As a result, stable tiny silver nanoclusters with around a 1-nm size and a relatively narrow particle size distribution were obtained using toluene as a liquid medium. The nanoclusters were characterized with dynamic light scattering, transmission electron microscopy, electron diffraction, and optical methods. The results confirmed the formation of nanoclusters with an absorbance peak around 300 nm and the absence of 400-nm peaks typical for silver nanoparticles. Fluorescence tests allowed for establishing the amorphous structure of the synthesized nanoclusters occupying the intermediate position between few-atom nanoclusters and nanoparticles. The nanoclusters obtained were proven to be stable for more than 3 months. The experiments also revealed the possibility of performing high-temperature plasma-chemical reactions that can be applied in fusion technology.

Preparation, characterization and mechanical properties analysis of SAC305-SnBi-Co hybrid solder joints for package-on-package technology

The development of hybrid solder for chip packing is a major 3D packaging research topic. The incorporation of with low melting points into solder materials has been used in low-temperature packaging. Hybrid solder struggles to enhance low-temperature solder efficiency and mechanical properties. This work examined the effects of Co elements on microstructure and intermetallic compound (IMC) morphology of SAC305-SnBi-Co hybrid solder generated by reflow welding on electroless nickel immersion gold (ENIG) substrate at various temperatures. Moreover, mechanical characteristics and failure behavior of joints were extensively explored. The results show that the addition of 0.05% Co reduced the melting range of the solder and improved the wettability of SnBi solder. According to transmission electron microscopes (TEM) and electron diffraction spots (EDS), the crystal structure of the grains is (Cu, Co)6Sn5 basic-centered monoclinic crystal. Fourier analysis of high-resolution images yields deformed lattice fringes, indicating that Co atoms fill Cu6Sn5's lattice gap in IMC. The shear strength of SAC305/SnBi hybrid solder joints with Co rises and then decreases with temperature. The highest shear strength of solder joints with 0.05% Co (40 nm) is 73.2 MPa at 220 °C, whereas joints with 0.1%Co are 67.5 MPa. Combined with the fracture morphology, the proportion of IMC fracture mode decreased after adding Co element.

Особенности формирования ультрамелкозернистой структуры в технически чистом никеле под влиянием равноканального углового прессования

Using transmission electron diffraction microscopy, the features of the formation of an ultrafine-grained structure in commercially pure nickel after equal-channel angular pressing were studied. It has been established that the formed ultrafine-grained structure is represented predominantly by anisotropic grains with a cellular or fragmentary substructure. It has been shown that particles of secondary phases, namely Ni4N, Ni3C, NiO, and Ni2O3, are present at the grain boundaries and junctions. The following sources of internal stresses have been established: 1) grain junctions; 2) grain boundaries; 3) Ni2O3 particles located in the volume of the grains on dislocations; 4) dislocation structure in the grains or parts of grains where particles of secondary phases are absent. It was found that the internal fields are predominantly elastic. The amplitude of the curvature-twist of the crystal lattice elastic field increases with the grain size refinement.

Analysis of contact zone of coating-substrate system exposed to irradiation with a pulse electron beam

Using the wire-arc additive manufacturing method (WAAM) on a 5083 aluminum alloy substrate, a non-equiatomic Mn – Cr – Fe – Co – Ni high-entropy alloy (HEA) coating was formed. By scanning and transmission electron diffraction microscopy we analyzed the structure, phase and elemental composition of the contact zone after irradiation with high-current low-energy electron beams with the following parameters: accelerated electron energy 18 keV, electron beam energy density 30 J/cm2, electron beam pulse duration 200 µs, number of pulses 3, pulse repetition rate 0.3 s–1. Multiphase multielement submicro- and nanocrystalline structures are formed predominantly in the substrate, which has a lower melting temperature compared to HEAs. Mutual doping of the coating – substrate system occurs in the contact layer, which has sinuous boundaries. The contact layers adjacent to the substrate and coating have the structure of high-speed cellular crystallization. In the layer adjacent to the substrate, the cells are formed by a solid solution of magnesium in aluminum. Interlayers of the second phase, enriched in atoms of the coating and substrate, are revealed along the cell boundaries. In the layer adjacent to the coating, the cells are formed by an alloy of composition 0.17Mg – 20.3Al – 4.3Cr – 16.7Fe – 9.3Co – 49.2Ni corresponding to the coating. Interlayers of the second phase, enriched mainly in magnesium and, to a lesser extent, in atoms of the HEA coating, are located along the cell boundaries. Central region of the contact zone with a thickness of ~1700 μm is formed by lamellar crystallites, which indicates the eutectic nature of its formation. Its main element is aluminum (≈77 at. %).