Subsequent Delamination Research Articles

Revealing interfacial degradation of Bi2Te3-based micro thermoelectric device under current shocks

Micro thermoelectric devices (micro-TEDs) offer great potential for IoT and electronic thermal management. However, they face challenges with reliability under high current densities. This study elucidates the failure mechanisms of Bi2Te3-based micro-TEDs subjected to current shocks. Experimental results indicate that at a high current density of 1800 A/cm2, the internal resistance of micro-TEDs increased by 12.9 % to 2.034 Ω. This led to a 52.0 % decrease in maximum output power at a 20 K temperature difference, dropping to 1.53 mW. Additionally, as the frequency of ON/OFF current applied to micro-TED increases, the resistance growth rate jumped from 0.764 mΩ/h for slow power cycling to 2.328 mΩ/h for fast power cycling. This indicates that higher cycling frequencies exacerbate the degradation of the device. In-situ TEM analysis revealed that current-induced elemental diffusion and electrical stress release led to the formation of NiTe2 nanoparticles and intergranular fractures within the Bi2Te3 materials. These results indicate that interfacial degradation and subsequent grain delamination are primary causes to micro-TED failure under current shocks. These findings underscore the significance of considering electrical stress in micro-TED design to enhance reliability and performance for high-power applications.

Synergistic Impact of Alloying with Ni on Cu Cathode Interfaces for Fluoride Batteries.

All-solid-state fluoride batteries have the potential to achieve energy densities significantly higher than those of lithium-ion batteries. A common cathode material for fluoride batteries is Cu. Cu has a low polarization, but its rapid capacity degradation due to grain growth and subsequent delamination from the solid-state electrolyte are critical issues. To enhance the performance of Cu-based cathodes in all-solid-state fluoride batteries, we explore alloying of Cu with Ni to create metastable solid solution phases (CuxNi1-x with x = 0, 0.32, 0.52, 0.72, 0.89, and 1.0). Compared to Cu, Ni has a higher polarization but exhibits superior capacity retention. The Cu0.72Ni0.28 alloy demonstrates a polarization as low as Cu, but it has a significantly improved capacity retention, which is comparable to Ni. Transmission electron microscopy observations demonstrate that the thin Ni-rich region formed near the interface inhibits Cu grain growth and delamination from the LaF3 electrolyte. By incorporating an appropriate amount of Ni into Cu, Cu-Ni alloy films combine the advantages of both metals, improving the performance of fluoride batteries.

Exceptional cryogenic-to-ambient impact toughness of a low carbon micro-alloyed steel with a multi-heterogeneous structure

A low-carbon micro-alloyed (LCMA) steel with a body-centered cubic (bcc) crystal structure suitable for extremely low temperatures was developed by overcoming the intrinsic ductile-to-brittle transition in bcc alloys at cryogenic temperatures. The excellent cryogenic-to-ambient impact toughness in the LCMA rolled plate results from its heterogeneous microstructure, which gradually changes from bamboo-like ultrafine grains (∼ 1.1 μm) on the surface to relatively equiaxed coarse grains in the core (∼ 3.4 μm), accompanied by a distinct texture gradient variation. The heterostructured LCMA steel displays a cryogenic impact toughness of ∼200 J/cm2 at 77 K, which is 24 times higher than the coarse-grained LCMA steel. Such high impact toughness of heterostructured LCMA arises from the coordinated deformation mechanisms over different length-scales coupled with delamination toughening. At 77 K, the heterostructured steel plate deforms by forming cellular sub-structures at the core to the surface, which refines the microstructure and promotes hetero-deformation induced (HDI) hardening to improve intrinsic toughening. Moreover, the subsequent delamination process induces extrinsic toughening by shielding and blunting the cracks, with the local plane-stress conditions induced by delamination promoting ductile fracture of the coarse grains in the core regions. This low alloy steel with its heterogeneous microstructure exhibits extraordinary impact toughness at cryogenic temperatures highlights the possibility of materials design strategies for sustainable development.

Towards dynamic in situ observation of flax fibres under varying water contents through environmental SEM and X-ray tomography

Flax fibre represents one of the most promising natural components for the development of new innovative high-performance biobased composite materials. Their properties are closely related to the lumen, the central cavity of the fibre, which was only studied, to date, under unrealistic environments as in dry conditions. The objective of the current study is to characterise, at a micrometre-scale, the surface and volume modifications induced by exposure of fibres to humid atmospheres. Different dynamic characterization strategies have shown a significant opening of the hydrated lumen "channel". Values of this opening rate are discussed in the light of potential biases linked to the investigation technique (SEM versus X-ray tomography), and to the adopted acquisition approach (in situ versus ex situ). By eSEM, after a 5 min. exposure to the water-saturated environment for instance, the lumen opening value was measured at 36 ± 2% for ex-situ hydration of the bundles with a subsequent delamination of the fibre, while it was only 15 ± 2% when hydration was progressively conducted into the SEM chamber. By microtomography, the lumen swelling for the single fibre was estimated to be within the same order of magnitude, about 7%, after hydration and measurements performed under realistic atmospheric pressure.

The Lithosphere and Upper Mantle of the Western‐Central Mediterranean Region From Integrated Geophysical‐Geochemical Modeling

AbstractThis study integrates geophysical‐geochemical data to investigate the thermochemical structure of the lithosphere and sublithospheric mantle, along the Southern Tyrrhenian Basin, Apennines, Adriatic Sea, Dinarides, and Carpathians‐Balkanides. We present the lithospheric structure of the Adria microplate and the two opposing mantle slabs along its NE and SW margins. The modeling shows the presence of two asthenospheric mantle wedges aligning with the Apenninic and Dinaric continental mantle slab rollback, along with cold (−200°C) sublithospheric anomalies beneath Adria's NE and SW margins. In the northern Adria region, the lithosphere undergoes synchronous thinning in the Tyrrhenian domain and thickening toward the forefront of the northern Apennines. This is associated with the northeastward rollback of the SW Adriatic slab, leading to subsequent delamination of the continental mantle. In the southern Adria region, the complex deep structure results from the variably oriented lithospheric slabs, and nearly 90‐degree shift of the tectonic grain between the southern Apennines and the Calabrian Arc. At the SW Adria margin, beneath the northern Apennines, the thermal sublithospheric anomaly is attached to the shallower lithosphere, while a slab gap is modeled in the southern Apennines. One possibility is that the gap is due to a recent horizontal slab tear. Along the NE margin of Adria, the thermal anomaly penetrates to depths of about 200 km in the northern Dinarides and 280 km in the southern Dinarides, shallower than the SW Adria anomaly, which extends to at least 400 km depth.

Crustal evolution of a continental magmatic arc from subduction to collision: A case study in the Gangdese arc, southern Tibetan Plateau

Magmatic arcs are the main environment where continental crust is created on the post-Archean Earth; however, how juvenile arc crust evolves into mature continental crust is still controversial. In this study, we report new bulk-rock major and trace elements, Sr-Nd isotopes, and zircon U-Pb ages and Hf isotopes from a large suite of granites collected from the eastern segment of the Gangdese arc, southern Tibetan Plateau, which record a complete history of arc crust evolution from Mesozoic subduction to Cenozoic collision. These new data show that Gangdese crust-derived granites generated during the subduction to collisional stages record significant geochemical changes with age, indicating that the bulk composition, lithological makeup, and thicknesses of the arc crust evolved over time. Here, we propose that the Gangdese arc had a thick juvenile crust with a small volume of ancient crustal components during late-stage subduction of the Neo-Tethys Ocean, a thin juvenile crust with heterogeneously distributed ancient crustal materials during early collision, and a thick juvenile crust with minor proportions of ancient rocks during late collision. This implies that the arc experienced episodes of crustal thickening during the Late Cretaceous and Eocene, interspersed by periods of thinning during the Paleocene and Miocene, and several discrete episodes of partial melting in the lower arc crust, and cycling or recycling of juvenile and ancient crustal materials within the arc crust and between the crust and mantle. We suggest that shallow subduction of the Neo-Tethys during the Late Cretaceous promoted tectonic thickening of the arc crust, partial melting of lower crust, and formation of high Sr/Y granites. After the onset of the Indo-Asian collision, breakoff of the subducted Neo-Tethyan oceanic slab during the Paleocene/early Eocene allowed thinning of the overlying arc crust and generation of granites derived from juvenile and ancient crustal sources. Continued underthrusting of the Indian continental crust and subsequent delamination of thickened lithospheric mantle led to thickening and thinning of the arc crust, respectively, and partial melting of thickened lower crust and generation of high Sr/Y granites during the Oligocene and Miocene. Using the Gangdese as an analogue for post-Archean continental margins, we suggest that the repeated thickening and thinning of arc crust, and associated multistage remelting of the lower arc crust, and material cycling or recycling within the crust and between the crust and mantle from subduction to collision are common processes that drive maturation of juvenile arc crust.

Spontaneous de-bonding, buckling and delamination of an elastic plate adhering to a rigid base: theoretical limits

An infinitely long elastic plate is under compression and adhering to a flat rigid base. Many studies have investigated such a layer with a pre-existing flaw in the bond (i.e. an initially de-bonded region) which may then lead to buckling and possibly to delamination. The present investigation considers the possibility of spontaneous de-bonding and simultaneous buckling, followed by delamination, in an initially homogeneous stress field without a pre-existing flaw. It is shown that a sufficiently large pre-stress can lead to this sequence of events. This limiting pre-stress depends on the plane strain elastic modulus, the layer thickness and the stiffness characteristic of the adhesion law. These results lead to theoretical limits on the pre-stress for the prevention of de-bonding, buckling and subsequent delamination under ideal bond conditions.

The dawn of MXene duo: revolutionizing perovskite solar cells with MXenes through computational and experimental methods.

Integrating MXene into perovskite solar cells (PSCs) has heralded a new era of efficient and stable photovoltaic devices owing to their supreme electrical conductivity, excellent carrier mobility, adjustable surface functional groups, excellent transparency and superior mechanical properties. This review provides a comprehensive overview of the experimental and computational techniques employed in the synthesis, characterization, coating techniques and performance optimization of MXene additive in electrodes, hole transport layer (HTL), electron transport layer (ETL) and perovskite photoactive layer of the perovskite solar cells (PSCs). Experimentally, the synthesis of MXene involves various methods, such as selective etching of MAX phases and subsequent delamination. At the same time, characterization techniques encompass X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy, which elucidate the structural and chemical properties of MXene. Experimental strategies for fabricating PSCs involving MXene include interfacial engineering, charge transport enhancement, and stability improvement. On the computational front, density functional theory calculations, drift-diffusion modelling, and finite element analysis are utilized to understand MXene's electronic structure, its interface with perovskite, and the transport mechanisms within the devices. This review serves as a roadmap for researchers to leverage a diverse array of experimental and computational methods in harnessing the potential of MXene for advanced PSCs.

Conductive filament distribution in nano-scale electrochemical metallization cells.

We report a combined experimental and theoretical study of the spatial distributions and sizes of conductive filaments in nano-scale electrochemical metallization (ECM) cells. Each cell comprises a silver nanocube as active electrode, a titanium dioxide (TiO2) or aluminum oxide (Al2O3) layer as dielectric, and a highly-doped silicon substrate as passive counter electrode. Following electroforming of the ECM cell and subsequent mechanical delamination of the silver nanocubes, current maps at previous particle locations reveal an intriguing metal distribution in the TiO2, with preferential accumulation close to the original locations of the nanocube edges. We assign this behavior to electric field enhancements close to the cube edge positions. In contrast, filaments in Al2O3 layers show a comparatively homogenous distribution, which may be assigned to its lower dielectric permittivity. By increasing the oxide thickness, the total area of conductive spots in the current maps increases monotonically for both materials. Kinetic Monte-Carlo simulations of ion migration dynamics in TiO2 confirm the experimental observations, describing both the preferred locations and oxide thickness-dependent metal loadings associated with filament formation. Overall, our findings are highly valuable for the design of future electrochemical metallization cells, especially in the sub-100 nm regime, where optimal filament control is of major importance for achieving lowest device-to-device variability.

Ultrafast Laser Writing of Liquid Crystal Waveguides

With the development of conformable photonic platforms, particularly those that could be interfaced with the human body or integrated into wearable technology, there is an ever-increasing need for mechanically flexible optical photonic elements in soft materials. Here, we realize mechanically flexible liquid crystal (LC) waveguides using a combination of ultrafast direct laser writing and ultraviolet (UV) photo-polymerization. Results are presented that demonstrate that these laser-written waveguides can be either electrically switchable (by omitting the bulk UV polymerization step) or mechanically flexible. Characteristics of the waveguide are investigated for different fabrication conditions and geometrical configurations, including the dimensions of the waveguide and laser writing power. Our findings reveal that smaller waveguide geometries result in reduced intensity attenuation. Specifically, for a 10-μm-wide laser-written channel in a 14-μm-thick LC layer, a loss factor of −1.8 dB/mm at λ = 650 nm was observed. Following the UV polymerization step and subsequent delamination of the glass substrates, we demonstrate a free-standing flexible LC waveguide, which retains waveguide functionality even when bent, making it potentially suitable for on-skin sensors and other photonic devices that could interface with the human body. For the flexible LC waveguides fabricated in this study, the loss in a straight waveguide with a cross-sectional area of 20 μm × 20 μm was recorded to be −0.2 dB/mm. These results highlight the promising potential of electrically responsive and mechanically moldable optical waveguides using laser writing and UV-assisted polymer network formation.

Orogenic cyclicity and episodic tectono-magmatic processes in the formation of the Paleozoic northern Yili magmatic arc, Central Asian Orogenic Belt

To understand the orogenic cyclicity that built the northern Yili magmatic arc in the southern Balhkash-Yili arc of the Central Asian Orogenic Belt, we synthesize its tectono-magmatic processes using new and existing U-Pb geochronological dates (228), Hf-in-zircon (1605 spots), bulk-rock geochemical data (1458), and Sr-Nd isotopic analyses (461) of magmatic rocks. Based on temporal-spatial distribution of magmatic rocks and their geochemical composition, four magmatic episodes (ca. 470−440 Ma, 420−380 Ma, 350−320 Ma, and 300−260 Ma) punctuated by a magmatic gap (ca. 440−420 Ma) and two high-flux magmatic pulses (ca. 380−350 Ma and 320−300 Ma) were recognized. These episodic magmatic processes are proposed to be dynamically associated with changes in configuration of the subducted Junggar oceanic slab, including 470−440 Ma initial subduction, 440−420 Ma flat subduction, 420−380 Ma retreating subduction, 380−350 Ma advancing subduction, and 350−320 Ma retreating subduction, followed by slab break-off in ca. 320−300 Ma and subsequent lithospheric delamination in a post-collisional setting during the Permian (ca. 300−260 Ma). In addition, tectonic transition (ca. 380 Ma and 320 Ma) from extension to compression were suggested to be closely related to the two phases of porphyry Cu mineralization events in the Balkhash-Yili arc. High crustal thickness and more mature arc evolution with prominent crust-mantle interaction may be responsible for the significant porphyry Cu endowment in the northern Balkhash-Yili arc.

Minute-level-fast and recyclable large-area monolayer graphene transfer onto polymer membranes

Monolayer graphene-based composites are of immense importance for research and applications in the microelectronic and thermal-management fields. For the current continuous production of monolayer graphene protocols, chemical etching of the catalyst layer acts as the bottleneck, which is tedious, expensive, and polluting. Thus in this work, by combining chemical etching and mechanical exfoliation, copper foil etching has been compressed from hours to 30 s, with the foil entirely recyclable and reusable. Furthermore, the whole transfer process could be confined within 7 min, including all pre- and post-treatments, without the usage of any intermediate, glue, electricity, vacuum, heat, or pressure. And this minute-level-fast monolayer graphene transfer could be performed continuously multiple times. The key to this novel transfer method is the superficial etching and the subsequent delamination of copper foil off graphene. In-situ OM, AFM, SEM, Raman, and UV–vis spectra have been employed to carefully inspect the transfer mechanism, effectiveness, and quality. The prepared monolayer graphene/polymer composite membrane is ultrathin (∼200 nm), conductive, highly transparent (93.9%), and flexible simultaneously. Its application as an ultrathin, efficient, and conformable Joule heating membrane-form device has been demonstrated. This minute-level-fast transfer is well-adapted to continuous monolayer graphene production and could considerably improve their practicality and efficiency. Additionally, this study provides more understanding of the interface between graphene-polymer and graphene-catalyst and a minute-level-fast route to fabricate 2D-based polymeric composite materials.

Step-by-Step Guide for Synthesis and Delamination of Ti3 C2 Tx MXene.

To advance the MXene field, it is crucial to optimize each step of the synthesis process and create a detailed, systematic guide for synthesizing high-quality MXene that can be consistently reproduced. In this study, a detailed guide is provided for an optimized synthesis of titanium carbide (Ti3 C2 Tx ) MXene using a mixture of hydrofluoric and hydrochloric acids for the selective etching of the stoichimetric-Ti3 AlC2 MAX phase and delamination of the etched multilayered Ti3 C2 Tx MXene using lithium chloride at 65 °C for 1 h with argon bubbling. The effect of different synthesis variables is investigated, including the stoichiometry of the mixed powders to synthesize Ti3 AlC2 , pre-etch impurity removal conditions, selective etching, storage, and drying of MXene multilayer powder, and the subsequent delamination conditions. The synthesis yield and the MXene film electrical conductivity are used as the two parameters to evaluate the MXene quality. Also the MXenes are characterized with scanning electron microscopy, x-ray diffraction, atomic force microscopy, and ellipsometry. The Ti3 C2 Tx film made via the optimized method shows electrical conductivity as high as ≈21,000 S/cm with a synthesis yield of up to 38 %. A detailed protocol is also provided for the Ti3 C2 Tx MXene synthesis as the supporting information for this study.

Prospects and limitations of a clay-enabled pre-concentration method for spectrophotometric quantification

The width of applicability of a pre-concentration protocol for quantifying analytes from dilute aqueous solutions, relying on adsorbate loading onto Bentone LT and subsequent clay delamination, was studied. The applicability of the protocol was investigated on seven organic (cetyltrimethylammonium bromide (CTAB), diclofenac, topotecan, methyl red) or inorganic (iron(ΙΙΙ) chloride, cobalt(ΙΙ) nitrate, copper(II) acetate) molecules. The study verified that Bentone LT adsorbed all studied analytes from dilute aqueous solutions. The relationship between adsorbate concentration in loading medium and adsorbate availability in supernatant upon delamination was investigated. A behaviour approximating a linear relationship with either a single or two linear ranges was observed for most adsorbates at low loading concentrations. For diclofenac and Fe(III) this relationship was described by a logistic regression model. Concentrations in the linear portion of the quasi-desorption curves correspond to environmental levels for certain analytes tested. High pre-concentration factors were achieved for many adsorbates (about 71-fold, 34-fold, and 29-fold for Co(II), Cu(II), and methyl red, respectively). Lower pre-concentration factors (about 12-fold, 8-fold, and 2-fold) were obtained for topotecan, Fe(III), and CTAB, respectively. For those adsorbates where pre-concentration was significantly successful, the lowest adsorbate concentration that could be reliably detected decreased by a factor ranging between 46- and 5-fold, when compared to the limit of quantitation (LOQ) of the hyphenated quantification assay not supplemented by a pre-concentration step. Pre-concentration of specific analytes in the presence of mixtures of chemicals, at environmentally-relevant levels or above, was equally successful. Limitations of the pre-concentration methodology were studied: The methodology works poorly when hyphenated to assays that depend on negatively charged compounds for ion-pair formation. Low pH values that may be required to favour adsorption, limit quasi-release efficiency. Adsorbate release, in the latter cases, is effective though upon pH increase, without delamination.

Composition and Evolution of Continental Crust at Orogenic Belts: Constraints From a 3‐D Crustal Model of Southeast China

AbstractThe chemical composition of continental crust is fundamental and crucial to understanding its origin and evolution. Orogenic belts make up about 30% of the global continental crust, yet their chemical compositions are still poorly constrained. In this study, we report an overall estimate for the continental crust composition of a collisional orogenic belt terrane: the Southeast China. The estimate is obtained through a 3‐D crustal model combining a lithology proportion model and probability density function models for element concentrations of various lithologies. Based on our model, the Southeast China crust is amongst one of the most evolved continental crust composition estimates (71.0% SiO2 content for the upper crust and 64.7% SiO2 for the bulk crust). A strong correlation between SiO2 and the chemical index of alteration (CIA) of different composition models for upper continental crust (UCC) indicates that chemical weathering is a controlling factor for the development of a felsic UCC. In contrast, weak correlations of SiO2 with Ninorm (15.9*Ni/Al2O3) and CIA suggest that igneous differentiation and chemical weathering act together to modify the composition of the bulk continental crust. Orogenic belt terranes like the Southeast China can develop a highly evolved crustal composition, especially for the upper crust, due to extensive intracrustal reworking and differentiation, enhanced chemical weathering, and potential subsequent delamination and removal of thickened crust root. Therefore, an overall estimation of the average composition of continental crust should take into account the more evolved composition of orogenic belts.

In-situ synthesized gold nanoparticles modified Mo2C MXene for surface enhanced Raman scattering

Herein, we demonstrate a proof-of-concept of using Mo2C MXene and gold nanoparticles (NPs) hybrid as an efficient surface-enhanced Raman scattering (SERS) substrate for organic pollutants detection. Mo2C MXene/Au hybrid is synthesized by an in-situ reduction of Au3+ ions onto Mo2C MXene nanosheets and characterized for its optical and structural properties. For the hybrid structures, we first synthesized Mo2C MXene by hydrofluoric acid etching of Mo2Ga2C and subsequent delamination with dimethyl sulfoxide to obtain few-layered nanosheets. The concentration of HAuCl4 for in-situ formation of Au was optimized with UV–Vis spectroscopy and probed with high resolution transmission electron microscopy. X-ray diffraction confirms the presence of Au NPs and MXene, while scanning and transmission electron microscopy analyses reveal the loading of Au NPs with an average size of ~ 9 nm on MXene few-layer particles. Based on our X-ray photoelectron spectroscopy results, we proposed a synthesis mechanism in which the functional groups of Mo2C MXene take an active part in reducing the gold precursor to form gold NPs. The optimized Mo2C/Au hybrid was then coated onto silicon and studied as a potential SERS substrate utilizing methylene blue as a model dye. Further, the comparison of the studies with rhodamine 6G confirms and justifies the role of the Mo2C/Au hybrid in signal enhancement. The preliminary findings demonstrate an enhancement factor of 2.2 × 104 and a detection limit of 0.01 μM (10–8 M) for optimal Au loading for MB. The fabricated SERS substrate is stable for nearly 1 month and exhibits excellent signal reproducibility with ~ 88% retention of the signal. These findings can be further extended to other MXenes to obtain in-situ synthesized hybrid for SERS as well as other applications including sensors, photocatalysis, and electrocatalysis.Graphical abstract

Theoretical modelling of the effect of thermal delamination of an asphalt concrete pavement from a rigid foundation of a road or bridge

In the practice of road construction, one of the most common phenomena accompanied by delamination, subsequent cracking and destruction of the asphalt concrete pavement on a rigid (cement concrete or metal) base of a road or bridge is the effect of concentration of shear thermal stresses between the pavement and the base in the edge zones of the structure. They are caused by the fact that, as a rule, the coefficients of linear thermal expansion of the phases of the system have different values, which contributes to the occurrence of incompatible shrinkages and expansions in them. Under conditions of frequent temperature changes in heterogeneous asphalt concrete structures with thermomechanical incompatibility of their components, these effects can contribute to their accelerated aging. At the same time, with the thermomechanical compatibility of materials, a more favorable distribution of internal stresses of thermal and mechanical origin is achieved, which excludes premature degradation of the strength of the contacting phases and the entire system as a whole. Using the methods of strengthof materials and the finite element method, it has been established that under the conditions of a change in the temperature of the system during its seasonal and daily fluctuations, shear stresses are subjected to the highest concentration. They are localized in the edge zone of the plane of contact between the layers and increase with an increase in the thickness and modulus of elasticity of the upper layer. These stresses are the main reason for the occurrence of plastic deformations in these zones and subsequent delamination of the structure in them. It is proposed to reduce the concentration and level of generated high-gradient shear stresses by reducing the thickness of the asphalt concrete layer in these areas.

Adhesion of nanodiamond composite films on Ti substrates at room temperature via hybrid ion etching gun and coaxial arc plasma deposition

It has been extremely difficult for nanodiamond composite (NDC) films to be deposited on Ti due to a large thermal expansion coefficient difference. The native oxide layer on Ti is another problem preventing the appropriate adhesion of NDC films and subsequent delamination. In this work, innovative room temperature adhesion of 3 μm NDC films with 54 GPa hardness on Ti substrates was accomplished via a hybrid system of ion etching gun and coaxial arc plasma deposition (CAPD). Ar+ plasma etching is capable to terminate the superficial TiO2 layer and manipulates substrate morphology during CAPD provides instantaneous deposition of NDC films at room temperature.

Articular cartilage delamination at eight years following cellular-based repair procedures: a case reports

This report describes two cases of late cartilage delamination in two young adults after two different autologous cell-based techniques for cartilage restoration: 1. Matrix-assisted autologous chondrocyte implantation (MACI) and 2. Hyaluronic acid-bone marrow aspirate concentrate (HA-BMAC). Both cases demonstrate that even in patients who do not present with any ongoing symptoms after primary surgery, a cellular-based graft’s subsequent delamination can occur later. It is possible that regardless of the technique used or the time passed since the surgery, a graft failure may occur at some level, causing delamination of a previously asymptomatic cartilage restoration graft and a traumatic event with long-term follow-up. Surgeons must be alert to this injury and describe histologic findings to determine where failure occurs.

Effective delamination of a layered two-dimensional MCM-22 zeolite: Quantitative insights into the role of the delaminated structure on acid catalytic reactions

A layered precursor of MCM-22 (Mobil Composition of Matter-22), a representative two-dimensional MWW type zeolite, is a flexible, reliable platform for structural transformation via inter-layer swelling and subsequent pillaring or delamination. In particular, the delaminated MWW type zeolite, which is a few nanometers thick, is desirable for overcoming diffusional limits. Despite its promise, the conventional procedure to acquire the delaminated MCM-22 is complicated; the resulting particle is known as ITQ-2 (Instituto de Tecnologia Quimica Valencia-2). Here, we propose a simple, effective method for delaminating MCM-22 precursors into nanosheets; the calcination of swollen MCM-22 precursors resulted in successful delamination. A rigorous analysis of the structural and textural properties of the resulting delaminated forms revealed that a majority of the nanosheets had a 3–4 unit cell thickness along the c-axis, which were further formed via aggregation of particles having ca. 1–2 unit cell thickness and retaining the original intra-layer zeolite structure. In addition, we applied the MCM-22 zeolite and its derivatives (i.e., the aforementioned delaminated MCM-22 zeolite and ITQ-2) to two conventional acid catalytic reactions (methanol to hydrocarbons and toluene methylation). Furthermore, we could quantitatively correlate the catalytic performance as well as the deactivation degree of the three catalysts with the corresponding structural and acidic properties. Notably, unlike an initial expectation, the delaminated MCM-22 zeolite lowered both the catalytic activity and long-term stability. These could be attributed to the decreased acid sites in the two-dimensional micropores (mainly, those used to be present in the inter-layer) and the increased non-zeolitic acid sites (other than the micropores), respectively, by the delamination, hindering the proper uses as conventional acid catalysts.