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The surface oxidation of 2D transition metal dichalcogenides (TMDs) has recently gained tremendous technological and fundamental interest owing to the multi‐functional properties that the surface oxidized layer opens up. In particular, when integrated into other 2D materials in the form of van der Waals heterostructures, oxidized TMDs enable designer properties, including novel electronic states, engineered light‐matter interactions, and exceptional‐point singularities, among many others. Here, the evolving landscapes of the state‐of‐the‐art surface engineering technologies that enable controlled oxidation of TMDs down to the monolayer‐by‐monolayer limit are reviewed. Next, the use of oxidized TMDs in van der Waals heterostructures for different electronic and photonic device platforms, materials growth processes, engineering concepts, and synthesizing new condensed matter phenomena is discussed. Finally, challenges and outlook for future impact of oxidized TMDs in driving rapid advancements across various application fronts is discussed. [ABSTRACT FROM AUTHOR]

In this study, the oxidation of Ga–polar GaN(0001) surface simulated by using originally developed charge‐transfer‐type interatomic potential is reported on. The adjusted potential parameters reproduce the cohesive energies in the range of 0.3 eV atom−1 and atomic forces with correlation coefficient as high as 0.9, compared to the results of first‐principles calculations for more than 9000 structures associated with oxidation of GaN. The oxidation simulations reveal the formation of a periodic gallium oxide (GaOx) layer grown on GaN(0001) with O atoms replacing N atoms. The atomic distance between Ga–Ga in the GaOx layer along GaN[0001] direction is 3.05 Å, which is longer than wurtzite GaN (2.63 Å) and is quantitatively in agreement with the recent photoelectron holography measurement. The distances of the Ga atoms projected onto the GaN(11–20) plane are determined to be 3.19 Å for the GaOx layer and 2.79 Å for the interfacial GaN. These distances also align quantitatively with the scanning transmission electron microscopy imaging of the native oxide on GaN(0001). Further oxidation simulation in a larger model of 2304 atoms suggests the formation of the layered structure even in the subsequent layers away from the interface of GaN and gallium oxide. [ABSTRACT FROM AUTHOR]

The complex structure of Ti/HA (HA: hydroxyapatite) implants prepared by additive manufacturing technology plays an essential role in its application in bone repair. Digital light processing (DLP) is widely used to prepare bioceramics with complex structures. However, it is a challenge to prepare Ti/HA biomaterials by DLP due to the high ultraviolet (UV) absorption of Ti powder. In the present work, TiH2 powder coated with a TiO2 layer is selected to reduce the UV absorption and improve the curing depth for DLP printed green bodies of TiO2@TiH2/HA, because the TiO2@TiH2 powder can be reduced by 12.7% compared to the TiH2 powder without any oxidation. Then, the shell layer of TiO2 undergoes dehydrogenation and reduction reaction with the core phase of TiH2 during the sintering process to transfer TiO2@TiH2/HA into TixOy@Ti/HA. In addition, the effects of HA content on compressive strength and biocompatibility are investigated in the TixOy@Ti/HA biomaterials. The results show that when adding 60 vol%HA, the maximum monolayer curing depth of the slurry reaches 90.1 ± 3.5 µm. 40%TixOy@Ti/60%HA shows the maximum effect in promoting the pre‐osteoblast differentiation and a relatively high compressive strength of 48.7 ± 3.5 MPa. This work provides an experimental basis for the preparation of ceramic–metal composites with high UV absorptivity using DLP. [ABSTRACT FROM AUTHOR]

BACKGROUND: Nickel foam (NF) is widely used as battery electrode matrix and electrochemical process cathode. However, the surface of NF is prone to oxidation, which may affect its ability to reduce oxygen and produce H2O2, but the influence mechanism is still unclear. In this paper, surface oxidation of the NF was regulated by pickling and drying pretreatment, and the surface oxides were characterized by X‐ray photoelectron spectroscopy (XPS) and energy dispersive X‐ray spectrometry (EDS). The NF was used as the substrate, graphite powder as the catalyst, and PTFE as the binder to prepare graphite‐coated NF composite electrodes. The effect of NF surface oxidation on their ability to generate H2O2 was investigated. RESULTS: The results demonstrated that after pickling and drying, the NF surface generated a large amount of NiO, which increased the charge transfer resistance of the NF by 20.3%, and accelerated further reduction decomposition of H2O2. The rotating ring‐disk electrode (RRDE) tests further confirmed that NiO can reduce the two‐electron oxygen reaction selectivity, which was detrimental to H2O2 electrosynthesis. The graphite‐coated NF composite electrode with pristine NF as the substrate can produce 869.1 mg L−1 of H2O2 and maintain relatively good reusability. CONCLUSION: Overall, the surface oxidation of NF is not conducive to H2O2 electrosynthesis, and it is necessary to prevent oxidation during electrode preparation. This study provides a valuable reference for the preparation of NF electrodes and can promote the further study of in situ H2O2 electrosynthesis. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

van der Waals In2Se3 has attracted significant attention for its room‐temperature 2D ferroelectricity/antiferroelectricity down to monolayer thickness. However, instability and potential degradation pathway in 2D In2Se3 have not yet been adequately addressed. Using a combination of experimental and theoretical approaches, we here unravel the phase instability in both α‐ and β′‐In2Se3 originating from the relatively unstable octahedral coordination. Together with the broken bonds at the edge steps, it leads to moisture‐facilitated oxidation of In2Se3 in air to form amorphous In2Se3−3xO3x layers and Se hemisphere particles. Both O2 and H2O are required for such surface oxidation, which can be further promoted by light illumination. In addition, the self‐passivation effect from the In2Se3−3xO3x layer can effectively limit such oxidation to only a few nanometer thickness. The achieved insight paves way for better understanding and optimizing 2D In2Se3 performance for device applications. [ABSTRACT FROM AUTHOR]

Herein, flexible, Cd‐free, and all‐dry process Cu(In,Ga)(S,Se)2 (CIGSSe) solar cells on stainless steel (SUS) substrates are developed with manufacturing CIGSSe absorbers fabricated in real production line with large sample size of 0.94 × 1.23 m2. Air‐annealing process under a temperature of 130 °C, 1 atmospheric pressure, and air humidity of about 50% (accelerated oxidizing process) is conducted on absorbers for their oxidized surface. It is demonstrated for the first time that oxidized surface of CIGSSe absorbers after air‐annealing process gives rise to considerable increases in photovoltaic performances of CIGSSe solar cells. This occurs because of formation of native Inx(O,S)y buffer near CIGSSe surface formed after air‐annealing process, which yields self‐forming heterojunction, acting as charge separation and hole‐blocking barrier with increased valence band offset of native Inx(O,S)y/CIGSSe to 1.4 eV, thereby avoiding sputtering damage on CIGSSe surface. Therefore, carrier recombination rates at the interface and depletion regions of the solar cell are reduced, implying improvement of interface and near‐surface qualities. Ultimately, conversion efficiency of 16.7% for flexible, Cd‐free, and all‐dry process CIGSSe solar cell on SUS substrate is attained after the air‐annealing process (130 °C and 6 h) with potential toward Lab‐to‐Fab transition. [ABSTRACT FROM AUTHOR]

The copper oxide (CuO) nanostructures are synthesized via facile oxidation of Cu foil in an aqueous KOH solution at room temperature. A precleaned Cu foil immersed in a 0.1 M aqueous KOH solution for different time periods (36–72 h) systematically converts its surface into nanochained to rice husk morphology and then agglomerated dense nanoclusters. The impact of immersion time on the morphology and consequently supercapacitor performance is studied. The CuO nanostructure synthesized at an immersion time of 60 h shows a maximum specific capacitance of 302 Fg–1 at a scan rate of 2 mV s−1. The capacitance retention reaches up to 87% after 2000 cycles. [ABSTRACT FROM AUTHOR]

The electrocatalytic CO2 reduction (converting redundant CO2 into carbon‐neutral fuels) holds a great potential to battle the energy and environmental crisis. The Ag‐based materials stand out from the pool of catalysts because of its high Faradic efficiencies for CO formation. In this work, thin Ag polycrystalline film was synthesized on carbon papers by a simple vacuum evaporation method. After 15 minutes of O3 treatment under ambient temperature, the Ag electrocatalysts can produce CO with a Faradic efficiency of up to 93.3 % at −0.9 V versus reversible hydrogen electrode (vs. RHE), which is higher than that of pristine Ag. In addition, the Ag electrode retained ∼90 % catalytic selectivity for CO after a 10‐hour test. The characterizations show that the surface AgxO layer on Ag was reduced to Ag0, which not only reduces the activation energy barrier of the initial electron transfer but also provides an increased number of active sites for the reduction of CO2 to CO. [ABSTRACT FROM AUTHOR]

Designing copper (Cu) current collectors is a convenient way to stabilize lithium (Li) metal anodes. However, Cu current collectors and their derived Li/Cu anodes still face several obstacles, including lithiophobic and oxidizable Cu surface, cumbersome anode fabrication process, and low Li utilization. Here, a formate‐treatment strategy is presented to reconstruct Cu current collectors with a passivation layer covered Cu(110) surface. This method can easily be generalized to increase the lithiophilicity and oxidation resistibility of Cu current collectors. Using the formate‐treated Cu nanowire network as an anode current collector, the full cell consisting of a LiFePO4 cathode and Li/Cu anode with a low negative/positive capacity ratio delivers an excellent cycling performance with 74.8% capacity retention after 1000 cycles at 1 C. In addition, a concept of an upper current collector is introduced to simplify the manufacturing procedure of Li/Cu anodes. This work provides new insights into the design and construction of high‐performance Li/Cu anodes. [ABSTRACT FROM AUTHOR]

Copper nanostructures are promising catalysts for the electrochemical reduction of CO2 because of their unique ability to produce a large proportion of multi‐carbon products. Despite great progress, the selectivity and stability of such catalysts still need to be substantially improved. Here, we demonstrate that controlling the surface oxidation of Cu nanowires (CuNWs) can greatly improve their C2+ selectivity and stability. Specifically, we achieve a faradaic efficiency as high as 57.7 and 52.0 % for ethylene when the CuNWs are oxidized by the O2 from air and aqueous H2O2, respectively, and both of them show hydrogen selectivity below 12 %. The high yields of C2+ products can be mainly attributed to the increase in surface roughness and the generation of defects and cavities during the electrochemical reduction of the oxide layer. Our results also indicate that the formation of a relatively thick, smooth oxide sheath can improve the catalytic stability by mitigating the fragmentation issue. [ABSTRACT FROM AUTHOR]

Mechanical exfoliation yields high‐quality 2D materials but is challenging to scale up due to the small lateral size and low yield of the exfoliated crystals. Gold‐mediated exfoliation of macroscale monolayer MoS2 and related crystals addresses this problem. However, it remains unclear whether this method can be extended to other metals. Herein, mechanical exfoliation of MoS2 on a range of metallic substrates is studied. It is found that Au outperforms all the other metals in their ability to exfoliate macroscale monolayer MoS2. This is rationalized by gold's ability to resist oxidation, which is compromised on other metals and leads to a weakened binding with MoS2. An anomalously high monolayer yield found for Ag suggests that the large interfacial strain in the metal–MoS2 heterostructures measured by Raman spectroscopy also is a critical factor facilitating the exfoliation, while the relative differences in the metal–MoS2 binding play only a minor role. These results provide a new incentive for investigations of 2D material‐substrate combinations applicable where high‐quality 2D crystals of macroscopic dimensions are of importance. [ABSTRACT FROM AUTHOR]

Boron‐containing materials, and in particular boron nitride, have recently been identified as highly selective catalysts for the oxidative dehydrogenation of alkanes such as propane. To date, no mechanism exists that can explain both the unprecedented selectivity, the observed surface oxyfunctionalization, and the peculiar kinetic features of this reaction. We combine catalytic activity measurements with quantum chemical calculations to put forward a bold new hypothesis. We argue that the remarkable product distribution can be rationalized by a combination of surface‐mediated formation of radicals over metastable sites, and their sequential propagation in the gas phase. Based on known radical propagation steps, we quantitatively describe the oxygen pressure‐dependent relative formation of the main product propylene and by‐product ethylene. Free radical intermediates most likely differentiate this catalytic system from less selective vanadium‐based catalysts. [ABSTRACT FROM AUTHOR]

Polymer binders that combine active materials with conductive agents have played a critical role in maintaining the structural integrity of phosphorus anodes with a huge volume change upon sodiation/desodiation. Herein, the role of binders on the structural/chemical stability of phosphorus/carbon anode is spectroscopically uncovered through unexpected mechanism. Surprisingly, the selection of different binders is found to determine the oxidation degree of active phosphorus in various electrodes, which correlate well with their electrochemical properties. At a high oxidation degree, the electrode applying a conventional poly(vinylidene difluoride) binder displays the worst electrochemical properties, while the electrode using a sodium alginate binder delivers the best electrochemical performance (a highly reversible capacity of 1064 mAh g−1 with a 90.1% capacity retention at 800 mA g−1 after 200 cycles and an outstanding rate capability of 401 mAh g−1 at 8000 mA g−1) for its negligible oxidation. Additionally, the emergence/decomposition of surface intermediates, including (PO2)3− and (PO4)3− species, are observed in the discharging/charging processes via the ex situ P K‐edge X‐ray absorption spectroscopies. This novel discovery of the unique role of binders in phosphorus anodes, not only provides an opportunity to ameliorate their electrochemical properties, but also enables their practical applications in high‐energy sodium‐ion batteries. [ABSTRACT FROM AUTHOR]

The easy‐going oxidation of silicon nitride (Si3N4) at high temperature greatly hampers its potential applications. Here, we explored the reaction mechanism between β‐Si3N4 and O2 via density functional theory (DFT) calculation, which discloses that O atoms are preferentially adsorbed on the top of Si atoms and N2 starts to be generated as the dominant gas product at 2/3 monolayer (ML) O coverage. The vacancies formed by N2 removal attract the O adatoms to transfer to the site of the N vacancy, which accelerates the adsorption of O and the formation of Si–O bonds toward the growth of SiO2 product. The surface oxidation of β‐Si3N4 (0001) has been clarified by the unambiguous evolution of [SiN4‐nOn] (n = 0‐4) tetrahedrons going through from [SiN4] tetrahedron to [SiO4] tetrahedron, providing a deep insight into intrinsic oxidation process of Si3N4 ceramic. [ABSTRACT FROM AUTHOR]

Various strategies, such as increasing active site numbers and structural and surface engineering, have been used to improve the oxygen evolution reaction (OER) performance of transition‐metal dichalcogenides. However, it is challenging to combine these strategies in one system to realize the full catalytic potential. Now, an Ar/O2 plasma method is used to simultaneously induce exfoliation, surface reorganization (formation of an oxidative layer with rich oxygen vacancies), and phase transformation (cubic‐to‐orthorhombic) on CoSe2 to generate an exceptionally outstanding OER electrocatalysts. The as‐made samples require an overpotential of only 251 mV at 10 mA cm−2, outperforming commercial RuO2 and most reported OER catalysts. The striking catalytic activity originates from the optimized chemical and electronic environment. This work provides valuable insights into the design of promising OER electrocatalysts with high natural abundance via multilevel structural modulation. The use of Ar/O2 plasma facilitates exfoliation, cubic‐to‐orthorhombic phase transformation, and surface oxidative reorganization in cobalt diselenide (CoSe2). This leads to the optimal chemical and electronic structure for OER electrocatalysis. [ABSTRACT FROM AUTHOR]

Abstract: The oxidation and reduction of metal oxides and their interaction with the environment play a critical role in material stability and the ability to catalyze reactions. The local change in valence and formation of surface adsorbates affect the oxide electronic structure and chemical reactivity, yet are challenging to probe experimentally. In this paper a detailed study of the oxidation and reduction of Cr in the perovskite oxide family of La(1–x)SrxCrO3 using ambient pressure X‐ray photoelectron spectroscopy is presented. The incorporation of Sr increases the propensity to oxidize at the surface, leading to the presence of Cr4+ and Cr6+ principally confined to the top unit cell when in equilibrium with O2 gas. These acidic sites are readily reduced to Cr3+ in equilibrium with H2O vapor, and the resultant amount of hydroxyls formed from the dissociation of H2O is directly proportional to the density of surface sites formerly oxidized. The quantification of the redox stability of La(1–x)SrxCrO3 and the relationship between the extent of oxidation, reduction, and hydroxylation with Sr yield important insight into the surface functionality during electrochemical applications. [ABSTRACT FROM AUTHOR]

Abstract: Molybdenum carbides are widely adopted as efficient noble‐metal‐free electrocatalysts for hydrogen evolution reaction (HER). Their surface oxidation is inevitable under air but is often ignored, which can be detrimental for the accurate understanding and precise design of stable carbide catalysts. Herein, molybdenum carbide nanoladders are derived via pyrolyzing MoOx/amine hybrid precursors, and two types of impact of surface oxidation on their HER performance are obvious: (1) the downshift of d‐band center in Mo, and (2) the introduced steric hindrance from surface oxygen. Consequently, the negative hydrogen‐binding free energy (ΔGH*, −0.52 eV) of pristine MoC gradually increases to positive values with surface oxidation, indicating the effectively weakened strength of Mo−H. With moderate surface oxygen incorporation, a ΔGH* of almost 0 eV is in accordance with the efficiently promoted HER performance via a good balance of Volmer and Heyrovsky/Tafel steps in kinetics. The optimal catalyst supported on a Ti plate (1 cm2) gives a high hydrogen production rate of 0.35 mL min−1 at 300 mV with high stability over the self‐made water‐splitting configuration. This work does not only make us reacquaint the surface oxidation of carbides on electrocatalysis but also paves the way for developing efficient and stable catalysts via surface engineering. [ABSTRACT FROM AUTHOR]

In order to understand how oxidation rate of graphene surfaces affects single-stranded poly-thymine, poly(T)20, structure during physisorption, all-atom molecular dynamics simulations are performed. In aqueous solutions, poly(T)20 is a complex structure with stacked and coiled regions. However, on the graphene surfaces, there are three different regimes for the adsorption process, which heavily depends on the surface oxidation: (1) on pristine graphene or graphene oxide (GO) with low oxygen coverage (GO 5%) the stacked poly(T)20 structure becomes unfolded due to formation of strong π-π interactions with the surface, (2) on graphene oxide with moderate oxygen coverage (GO 10%-25%) the structure of poly(T)20 is well preserved because of the balance between van der Waals and electrostatic interactions, and (3) on graphene oxide with high oxygen content (GO 30%-60%) stacked poly(T)20 structure is locally disrupted due to formation of strong hydrogen bonds with the surface. Moreover, surface roughness due to the presence of oxygen groups plays a pivotal role in structural retention of poly(T)20 by preventing its nucleobases from forming π-π stacking interactions with the surface. [ABSTRACT FROM AUTHOR]

Liquid metal droplet wetting and dewetting transitions are shown using environmental stimuli to remove, reform, and transform droplet surface oxide. A comparison is made between the speed of oxide removal using NaOH and HCl, with NaOH proving to be significantly faster. The findings are applied to demonstrate a liquid metal switch controlled through purely environmental stimuli. [ABSTRACT FROM AUTHOR]

SrVO3 (SVO) is a model system for strongly correlated oxides and is highly promising as conductive layer in heterostructures. Therefore, the control of electronic properties and morphology are essential for the advanced applications. Here, the oxygen stability during and after the deposition is explored, as SVO film is expected to undergo different postdeposition thermal and atmosphere treatments during its integration in a heterostructure. Hence, the influence of oxygen stability on morphology and electrical properties of the metallic SrVO3 grown by pulsed laser deposition has been investigated. Films grown under vacuum (SrVO3− δ ) exhibit a very smooth surface while films grown under higher oxygen pressure roughen and present nanostructures at the surface. These nanostructures are found to be of Sr3V2O8 phase and their apparition can be controlled by the oxygen supply. Subsequent thermal treatments at different temperatures under same oxygen pressure prevent formation of the Sr3V2O8 phase, lead to the stoichiometric SrVO3, and thus improve the transport properties. In this study is shown the extreme sensitivity of SVO to oxygen and the conditions to obtain high quality smooth SVO films with improved electrical properties for electrode application. [ABSTRACT FROM AUTHOR]

Ricinoleate esters have desirable properties as biolubricants, but their oxidative stability has been questioned. To systematically study the stability of ricinoleate ester and its derivative, methyl esters of castor oil were prepared and methyl ricinoleate was isolated by solvent partitioning. Methyl 12-acetyl ricinoleate was synthesized from the methyl ricinoleate by interesterification with excess methyl acetate and was then purified by solvent partitioning. The rates of oxidation of methyl linoleate, methyl oleate and the two ricinoleate esters were measured by oxidation of lipid dispersed on glass beads under three temperatures (40-80 °C). The relative amounts of the unoxidized methyl esters were determined periodically by gas chromatography, and the peroxide value of the oils was also determined. The oxidation rates were determined as the peroxide value increase rate, as well as the ester disappearance rate, and the stability of the various esters was compared. Overall, methyl ricinoleate was much more oxidatively stable than methyl oleate at mildly elevated temperatures, and the acetylation of the hydroxyl group on the 12th carbon decreased the stability. [ABSTRACT FROM AUTHOR]

Difference X-ray photoelectron spectroscopy (D-XPS) revealed the surface oxidation process of a diamond-like carbon (DLC) film. Evaluation of surface functional groups on DLC solely by the C 1 s spectrum is difficult because the spectrum is broad and has a secondary asymmetric lineshape. D-XPS clarified the subtle but critical changes at the DLC surface caused by wet oxidation. The hydroxyl (C-OH) group was dominant at the oxidized surface. Further oxidized carbonyl (CO) and carboxyl (including carboxylate) (COO) groups were also obtained; however, the oxidation of CO to COO was suppressed to some extent because the reaction required C-C bond cleavage. Wet oxidation cleaved the aliphatic hydrogenated and non-hydrogenated sp2 carbon bonds (C-H sp2 and C-C sp2) to create a pair of C-OH and hydrogenated sp3 carbon (C-H sp3) bonds. The reaction yield for C-H sp2 was superior at the surface, suggesting that the DLC film was hydrogen rich at the surface. Oxidation of aromatic sp2 rings or polycyclic aromatic hydrocarbons such as nanographite to phenols did not occur because of their resonance stabilization with electron delocalization. Non-hydrogenated sp3 carbon (C-C sp3) bonds were not affected by oxidation, suggesting that these bonds are chemically inert. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The use of continuous galvanized steel sheet as feedstock material for press hardening leads to components of very high strength levels with classical cathodic corrosion protection. The present work provides an insight into this technology with special focus on surface oxidation and intermetallic phase formation during the austenisation process. For that reason hot dipped galvanized 22MnB5 steel sheets, with a blank thickness of 1.5 mm and an average coating weight of 70 g m−2, were annealed in a temperature range of 400-900°C in steps of 50°C without soaking before quenching in water. Surface and cross-cuts were analyzed by SEM, EDX, and XRD to illustrate the phase formation and the surface changes during thermal treatment. Corrosion behavior was also studied based on electrochemical investigations and an accelerated, cyclic, automotive corrosion tests called VDA, which is a mixture of salt spray test and alternating climate test. It was found that austenisation of galvanized steel sheet causes a significant change of the coating. The generated coating still offers cathodic protection for the steel substrate and has higher corrosion resistance than standard galvanized steel sheet. Surface oxidation also occurs during the press hardening process leading to a surface covered with successively arranged layers of Al2O3 and ZnO, containing also further oxidized alloying elements. [ABSTRACT FROM AUTHOR]

Methyl linoleate was deposited as a monolayer on a silica gel control and on silica gel supplemented with double or quadruple the control's amount of the transition metal ions (TMI) iron, copper, vanadium or titanium. The treatments were oxidized at 25 °C, and periodically samples were examined for peroxide values (PV) and by gas chromatography for oxidation products (GC). Comparison of the treatments revealed that: Surface oxidation on silica gel owes its high rate to TMI, which may speed free radical initiation. Epoxidation is catalyzed by the presence of vanadium and titanium. Scission products (SP) and unrecovered mass increased with the extent of oxidation probably because of increased free radical life time. [ABSTRACT FROM AUTHOR]

The effect of different surface conditions on the fatigue properties of cyclically loaded bending specimens of the case-hardened steel SAE 5115 (Material Number 1.7131) was investigated. The aim of the investigations was to achieve further knowledge of the processes that finally lead to the failure of case-hardened and cyclically loaded bending specimens. Surface roughness, microstructure and residual stress distribution were regarded as parameters that govern the fatigue process. On the basis of a well-defined adjustment of different surface conditions the effect of internal oxidation, surface roughness and residual stresses on fatigue crack initiation and growth were assessed. The effect of different parameters on the endurance limit has been quantified by the application of a fracture mechanics and a weakest-link approach. The calculations contributed to a deeper insight into the complex interaction between the parameters governing the fatigue process. [ABSTRACT FROM AUTHOR]

Based on the weakest-link concept a method is developed, from which the endurance probability of every surface and volume element of a case-hardened part, which is loaded near the endurance limit, can be calculated. A prerequisite for the calculation is knowledge of the hardness and residual stress distribution, the surface roughness and the surface oxidation depth. By multiplication of the endurance probabilities of neighboured elements the endurance probability of a limited region or of the whole part can be calculated, which includes an endurance limit determination. It is shown, that this model can be applied successfully to specimens of a carburized steel. The necessary model parameters can be gained from a set of reference specimens. Because of the possibility to formulate an endurance probability for every volume and surface element, there are no geometrical restrictions on the parts to be assessed. [ABSTRACT FROM AUTHOR]

Methyl linoleate with 5% by weight of methyl palmitate as an internal standard was deposited as a monolayer (20% by weight) on Silica gel H and oxidized at 7, 25, and 40°C. Oxidation was followed by iodometric PV practiced directly on aliquots of the silica gel. Lower temperatures gave higher PV maxima but after longer times. Oxidation of methyl linoleate at all three temperatures followed first-order kinetics, and the energy of activation was 15.0 kcal/mol. The products recovered from the chloroform-acetic acid layer of the peroxide determination were analyzed by GC and identified by El- and CI-MS. Calculation based on methyl palmitate as an internal standard showed that the total peak area decreased to about 40% that of the original methyl linoleate when the residual methyl linoleate was reduced to less than 2%. The chief nonscission products (NSP) of linoleate oxidation were epoxy, hydroxy, hydroxy-epoxy, dihydroxy, and trihydroxy methyl esters. The greatest NSP concentrations were obtained about the time of the greatest PV, and the yield at 40°C was greater than those at 7 and 25°C. Scission products (SP) increased rapidly until the greatest PV was reached. After this time, SP declined slightly and plateaued at 40°C, but at 7 and 25°C, SP continued to increase Slowly with further oxidation. [ABSTRACT FROM AUTHOR]

In article number 1601168, Ho Shin Kim, Yaroslava G. Yingling, and co‐workers investigate the effect of graphene oxidation on the adsorption of poly‐thymine single‐stranded DNA (ssDNA) via all‐atom molecular dynamics simulations. The cover illustrates the conformational changes of folded ssDNA on graphene and graphene oxide surfaces. This study found that oxidation rate of graphene surface is correlated to the ssDNA structural stability. [ABSTRACT FROM AUTHOR]