Conventional Glass Research Articles

Rapidly screening out refractory metallic alloys with high glass-forming ability by laser surface remelting

Compared with conventional metallic glasses, refractory metallic glasses (RMGs) with a mass of refractory element(s), high glass-transition temperature (Tg) and outstanding mechanical properties (like ultrahigh strength, high hardness and good wear resistance) exhibit fascinating potential applications in high temperature field. However, the development of RMGs is painfully slow, and one of the key problems is the lack of rapid and convenient way to screen out high glass-forming refractory alloys. In this study, a method for rapid evaluation of glass forming ability (GFA) based on laser surface remelting was provided. The high-efficiency screening-out method was validated in a classical glass-forming model system of Ni–Nb binary refractory alloys. The effects of different laser parameters on the glass formation and phase evolution were investigated by experimental analysis and finite element simulation. By correlating thermal history of the laser treatment with glass formation, the alloys with high GFA in Ni–Nb system was screened out rapidly. The screening-out efficiency of the novel method can be improved one order of magnitude, compared with that of the conventional techniques, and the materials cost can be reduced, especially for RMGs. The revealed formation mechanism of glassy and crystalline phases in time and spatial distributions influenced by thermal history under multi-scanning laser treatment can provide a significant insight in the construction of the bulk-metallic-glass materials and the related composite ones by laser additive manufactory.

Effect of ethanolic extract of propolis on antibacterial and microshear bond strength of glass-ionomer restorations to dentin

ObjectivesThis study was conducted to evaluate the effect of ethanolic extract of propolis on antibacterial and microshear bond strength of glass ionomer restorations to dentin. Materials and methodsConventional glass ionomer cement (Equia forte, GC Tokyo, Japan), resin-modified glass ionomer (Fuji II LC, GC Tokyo, Japan) and propolis powder (dried extract from honey bees) materials were used in this study. Both conventional glass ionomer and resin-modified glass ionomer were modified by two different concentrations of ethanolic extract of propolis (10 % and 25 % EEP). For antibacterial test, Streptococcus mutans strain was spread on agar petri dishes using a sterile swab. Discs of both glass ionomer restorative materials (without adding EEP, with 10 % EEP and with 25 % EEP) were fabricated within the agar plates. Antibacterial activity was evaluated by measuring the inhibition zones around each disc. For microshear bond strength test, 60 healthy human permanent molars were prepared by cutting occlusal surface and expose the dentin at the height of contour of all teeth then conditioned using poly acrylic acid conditioner, both glass ionomer restorative materials (without adding EEP, with 10 % EEP and with 25 % EEP) were mixed and applied on conditioned dentin surface by using tygon tube. Microshear bond strength was evaluated by the universal testing machine. ResultsTwo-way ANOVA test revealed that both glass ionomer type and different concentrations of EEP had significant effect on the antibacterial test results and microshear bond strength values (p < 0,05). Glass ionomer restorative material with 25%EEP had the highest antibacterial values whereas glass ionomer restorative material without modifications (control groups) had the lowest values. Resin-modified glass ionomer without any modification (control group) had the highest bond strength while resin-modified glass ionomer with 25%EEP had the lowest bond strength. ConclusionsIncorporation of ethanolic extract of propolis to glass ionomer restorative material increases the antibacterial effects of both conventional GIC and RMGI. Inspite of this advantage, it seems that it has deleterious effect on microshear bond strength to dentin.

Analysis of adhesion characteristics of steel back plates and encapsulants for fire-proof BIPV modules

Recently, researchers are actively exploring the use of steel plates as replacements for the backs of building integrated photovoltaic (BIPV) modules to achieve improved workability, reduced weight, and enhanced maintainability. It is crucial to note that the adhesion between steel plates and encapsulants must match the high level observed between conventional backsheets and glass surfaces. In this study, we assessed the adhesion between steel plates and encapsulants and proposed a method to enhance adhesion to the level of existing materials, such as backsheets and glass, by improving the surface of the steel plates and the lamination process. When steel plates were laminated with ethylene vinyl acetate (EVA) encapsulant at 150 °C (as per the preset process), the peel force measured by the 180° peel test was significantly low at 0.045 N/mm. However, it increased nearly 40 times to 1.70 N/mm due to the formation of a structure capable of physical interlocking through surface treatment and an increase in the lamination temperature by 20 °C. Furthermore, we evaluated the adhesion performance of polyolefin elastomer (POE) encapsulant, which demonstrated high adhesion of over 6.0 N/mm, comparable to that between the currently used encapsulants and backsheets. When we examined the surface-treated sample using a confocal microscope and a secondary electron microscope (SEM), the surface-treated sample exhibited a considerably rough surface with a high Rku value of 5 compared to the untreated sample. These modules can maintain high outputs even when exposed to the external environment for extended periods with fire-resistant properties.

The effect of applying a new formulation of CaCl2 on surface hardness of conventional glass ionomer

The effect of applying a new formulation of CaCl2 on surface hardness of conventional glass ionomer

High transparency, degradable and UV-protective poly(lactic acid) composites based on elongational rheology and chain extender assisted melt blending

Conventional polylactic acid (PLA) melt plasticization and toughening processes are typically achieved at the expense of PLA strength and transparency, which is clearly detrimental to its application in areas such as smart home and food packaging. Herein, an ultraviolet (UV)-protective PLA-based composite (PP6) that simultaneously achieves high strength (63.3 MPa), high plasticity (125.3 %), and enhanced toughness (4.3 kJ/m2) by adding only 6 wt% poly(3-hydroxybutyrate-4-hydroxybutyrate) (P34HB) under the assist of 1 wt% chain extender was prepared using melt blending technique. Benefiting from the cross-linking effect of the chain extender and the elongational flow during processing, the compatibility between P34HB and PLA, as well as the thermomechanical properties, heat resistance, and biodegradable properties of the composite, have been enhanced significantly. The extremely low melt enthalpy (1.9 J/g) and the low crystallinity PLA phase contribute to an appropriate transparency (78.3 % of glass in 400–1100 nm). The prepared composites display mid- and long-wave UV-protective performance, which is superior to conventional industrial glasses. Through the superior elongational rheology technology, PP6 maintains favorable overall properties even after six thermomechanical cycles. Collectively, the composite fabricated in this work is an attractive candidate for future applications such as smart windows, food packaging, agricultural films, and biomedical applications.

Effects of Incorporation of Titanium Dioxide Nanoparticles on Mechanical Properties of Conventional Glass Ionomer Cement

Background: Due to the poor mechanical properties of Glass Ionomer Cement (GICs), their use is limited to low stress-bearing areas. This study aimed to assess the effect of the addition of Titanium Dioxide (TiO2) nanoparticles on the flexural strength and surface hardness of GIC. Methods: In this in vitro study, 3, 5, and 10 wt.% TiO2 nanoparticles were added to Fuji II conventional GIC powder. The purity and composition of the as-synthesized titania were investigated by using XRD and FT-IR tools. The homogeneity of powder particles within the used matrix was evaluated under a Scanning Electron Microscope (SEM). Results: The SEM micrographs confirmed the homogenous mixing of TiO2 nanoparticles with GIC powder. Conclusion: Nevertheless, the flexural strength of experimental groups was not significantly different from that of the control group (p=0.384). However, the surface hardness of experimental groups was decreased in comparison with that of the control group (p&lt;0.001).

Ionic Conductivity of K-ion Glassy Solid Electrolytes of K2S-P2S5-KOTf System

Ternary glassy electrolytes containing K2S as a glass modifier and P2S5 as a network former are synthesized by introducing a new type of complex and asymmetric salt, potassium triflate (KOTf), to obtain unprecedented K+ ion conductivity at ambient temperature. The glasses are synthesized using a conventional quenching technique at a low temperature. In general, alkali ionic glassy electrolytes of ternary systems, specifically for Li+ and Na+ ion conductivity, have been studied with the addition of halide salts or oxysalts such as M2SO4, M2SiO4, M3PO4 (M = Li or Na), etc. We introduce a distinct and complex salt, potassium triflate (KOTf) with asymmetric anion, to the conventional glass modifier and former to synthesize K+-ion-conducting glassy electrolytes. Two series of glassy electrolytes with a ternary system of (0.9–x)K2S-xP2S5-0.1KOTf (x = 0.15, 0.30, 0.45, 0.60, and 0.75) and z(K2S-2P2S5)-yKOTf (y = 0.05, 0.10, 0.15, 0.20, and 0.25) on a straight line of z(K2S-2P2S5) are studied for their K+ ionic conductivities by using electrochemical impedance spectroscopy (EIS). The composition 0.3K2S-0.6P2S5-0.1KOTf is found to have the highest conductivity among the studied glassy electrolytes at ambient temperature with the value of 1.06 × 10−7 S cm−1, which is the highest of all pure K+-ion-conducting glasses reported to date. Since the glass transition temperatures of the glasses are near 100 °C, as demonstrated by DSC, temperature-dependent conductivities are studied within the range of 25 to 100 °C to determine the activation energies. A Raman spectroscopic study shows the variation in the structural units PS43−, P2S74−, and P2S64− of the network former for different glassy electrolytes. It seems that there is a role of P2S74− and P2S64− in K+-ion conductivity in the glassy electrolytes because the spectroscopic results are compatible with the composition-dependent, room-temperature conductivity trend.

Evaluation of magnetic inhomogeneities in non-stoichiometric Mg0.5Ca0.5Fe2O4 nanoferrite

Present work reports a systematic study on the evaluation of magnetic inhomogeneities in non-stoichiometric Mg0·5Ca0·5Fe2O4 nanoferrite (MCNF) by conducting exhaustive dc-magnetization, ac-susceptibility and 57Fe Mössbauer spectroscopic measurements and exchange bias investigations using training protocol down to 6 K. Rietveld fitting to PXRD established the formation of anticipated spinel fcc phase of MCNF (non-stoichiometric) along with a minute impurity phase of calcite. Scherrer method and HRTEM micrographs illustrated broad size distribution of MCNF nanoparticles with an average nanocrystallite size of ∼15 nm. Combined 57Fe Mössbauer spectroscopic and dc-magnetization analysis establishes coexistence of ferrimagnetic (67 %) & superparamagnetic (33 %) states at 300 K with notable Ms = 22 emu/g, Mr = 4 emu/g & Hc = 130 Oe and blocking of most of the nanoparticles of MCNF below 300 K. The coercivity followed the size-modified Kneller law for ferrimagnetic nanoparticles and the saturation magnetization abides the Bloch law. Moreover the frequency-dependent ac-susceptibility investigations revealed two magnetic transitions: (i) A transition at ∼ 330 K in the low frequency data attributed to the relaxation of blocked particles of bigger sizes under the superparamagnetic (SPM) regime and (ii) an irregularity at low temperatures is assigned to surface spin glass freezing. Surface spin glass freezing was further affirmed by the ageing experiments and dynamic scaling law. Furthermore, even the best fit to the dynamic scaling couldn't assert the existence of conventional spin glass phase due to slower spin-flip time of surface spins. A soft ferrimagnetic core of MCNF is enveloped with disordered surface spins, which manifest spin glass state. Concurrently, the findings of exchange bias at 30 K and training effect at 6 K affirmed that MCNF nanoparticles are presenting themselves as FM core- SG shell system. Our experimental findings suggested magnetic inhomogeneities comprised of superparamagnetism, ferrimagnetism and disordered surface spin glass state in the non-stoichiometric MCNF.

Wollastonite-containing glass-ceramics from the CaO–Al2O3–SiO2 and CaO–MgO–SiO2 ternary systems

Glass-ceramics (GCs) are polycrystalline materials produced from parent glasses by the controlled crystallization that results in crystalline phase(s) embedded in a residual amorphous matrix. Typically, GCs are produced by a conventional glass route with subsequent crystallization for which two heat treatments are usually applied, the former to generate nuclei and the latter being a crystal growth stage. Alternatively, another technically viable route for manufacturing GCs involves sintering of glass-powder compacts followed by crystallization (sinter-crystallization).Wollastonite-containing GCs from the CaO–Al2O3–SiO2 and CaO–MgO–SiO2 systems find a wide variety of uses in different technological fields, including construction, architecture, medical and high-tech fields. For example, a special type of wollastonite-containing GC marketed under the name of Neoparies®, which is stronger and lighter than natural stone, features high resistance to weathering/chemical attack and is manufactured on a large scale for construction and architectural applications. In the biomedical field, the well-known Cerabone® products have been used in bone-contact applications for many years.The main goal of this brief review is to provide a critical analysis of the experimental trials focusing on the synthesis of wollastonite-containing GC materials and to discuss the various fields of their application. Constitution of phase diagram of CaO–Al2O3–SiO2 and CaO–MgO–SiO2 systems are comprehensively discussed with connection to melt crystallization path and crystalline phase formation. Furthermore, special emphasis will be given to the production of wollastonite-containing GCs for construction and architectural purposes from natural raw materials and wastes, as well as to the recent advancement in developing wollastonite-containing GC biomaterials for bone repair.

A Second Glass Transition Observed in Single-Component Homogeneous Liquids Due to Intramolecular Vitrification.

On supercooling a liquid, the viscosity rises rapidly until at the glass transition it vitrifies into an amorphous solid accompanied by a steep drop in the heat capacity. Therefore, a pure homogeneous liquid is not expected to display more than one glass transition. Here we show that a family of single-component homogeneous molecular liquids, titanium tetraalkoxides, exhibit two calorimetric glass transitions of comparable magnitude, one of which is the conventional glass transition associated with dynamic arrest of the bulk liquid properties, while the other is associated with the freezing out of intramolecular degrees of freedom. Such intramolecular vitrification is likely to be found in molecules in which low-frequency terahertz intramolecular motion is coupled to the surrounding liquid. These results imply that intramolecular barrier-crossing processes, typically associated with chemical reactivity, do not necessarily follow the Arrhenius law but may freeze out at a finite temperature.

Systematic review and network meta-analysis of restorative therapy and adhesive strategies in root caries lesions

AimThis systematic review and network meta-analysis (NMA) aimed to establish a clinically relevant hierarchy of the different adhesive and/or restorative approaches to restore cavitated root caries lesions through the synthesis of available evidence. Materials and methodsA systematic search was conducted in Medline/Web of Science/Embase/ Cochrane Library/Scopus/grey literature. RCTs investigating ≥2 restorative strategies (restorative /adhesive materials) for root caries lesions in adult patients were included. Risk of bias within studies was assessed (Cochrane_RoB-2) and the primary outcome was survival rate of restorations at different follow-up times (6-/12-/24-months). Network meta-analyses were conducted using a random effects model stratified by follow-up times. I2-statistics assessed the ratio of true to total variance in the observed effects. All available combinations of adhesives (1-SE: one-step self-etch; 2–3ER: two-/three-step etch-and-rinse) and restorative materials (conventional composite (CC) as well as conventional and resin-modified glass ionomer cements (GIC, RMGIC)) were included. Risk of bias across studies and confidence in NMA (CINeMA) were assessed. Results547 studies were identified and nine were eligible for the NMA. In total, 1263 root caries lesions have been restored in 473 patients in the included clinical trials. Patients involved were either healthy (n = 6 trials), living in nursing homes (n = 1 trial) or received head-and-neck radiotherapy (n = 2 trials). There was statistically weak evidence to favour either of material/material combination regarding the survival rate. A tendency for higher survival rate (24-months) was observed for 2–3ER/CC (OR24mths 2.65; 95%CI=1.45/4.84) as well as RMGIC (OR24mths 2.05; 95%CI=1.17/3.61) compared to GIC. These findings were though not statistically significant and confidence of the NMA was low. ConclusionAn evidence-based choice of restorative strategy for managing cavitated root caries lesions is currently impossible. There is a clear need for more standardised, well-designed RCTs evaluating the retention rate of root caries restoration approaches.

Comparison of Light Field and Conventional Near-Eye AR Displays in Virtual-Real Integration Efficiency

Most existing wearable displays for augmented reality (AR) have only one fixed focal plane and hence can easily suffer from vergence-accommodation conflict (VAC). In contrast, light field displays allow users to focus at any depth free of VAC. This paper presents a series of text-based visual search tasks to systematically and quantitatively compare a near-eye light field AR display with a conventional AR display, specifically in regards to how participants wearing such displays would perform on a virtual-real integration task. Task performance is evaluated by task completion rate and accuracy. The results show that the light field AR glasses lead to significantly higher user performance than the conventional AR glasses. In addition, 80% of the participants prefer the light field AR glasses over the conventional AR glasses for visual comfort.

Evaluation of the Effect of Nanographene Oxide on Microleakage of Conventional and Resin-Modified Glass Ionomer.

One of the important features of the restorative materials is the ability to seal and prevent the microleakage. Glass ionomer cement (GIC) still exhibits some microleakage despite establishing a chemical bond to the tooth. The aim of this study was to evaluate the effect of nanographene oxide (nGO) on the microleakage of conventional (CGIC) and resin-modified glass ionomer cement (RMGIC). Thirty intact extracted molars were used. Class V cavities were prepared on their buccal and lingual surfaces. The samples randomly divided into two main groups of CGIC and RMGIC; each of them was randomly subdivided into three subgroups, including the group without nGO (control), the group with 1% nGO, and the group with 2% nGO. After restoring the cavities, they were subjected to thermocycling (1,000 cycles at 5/55°C). Two percent basic fuchsin solution was used to perform the microleakage test, and then the sectioned samples were examined by a stereomicroscope 40x. Kruskal-Wallis test, Dunn's test, and Mann-Whitney U test were used to analyze the data (P < 0.05). Group CGIC + 1% nGO at the gingival margin and group RMGIC + 1% nGO at both gingival and occlusal margins had significantly less microleakage than their control groups (P=0.008, P=0.002, P=0.023, respectively). Also, in these two groups, there were no significant differences between the microleakage of the occlusal and gingival margins (P=0.132, P=0.511, respectively), while in all other groups, the gingival microleakage was significantly higher than that of occlusal microleakage. The addition of 1% nGO significantly reduced the gingival microleakage of CGIC and the occlusal and the gingival microleakage of RMGIC, while the addition of 2% nGO did not cause a significant reduction in microleakage.

Flexible neural recording electrodes based on reduced graphene oxide interfaces

Conventional recording neural electrodes are made of stiff materials such as metal or silicon which triggers unwanted inflammation and does not provide intimate contact with brain tissue. Flexible neural electrodes have therefore been increasingly investigated to address these issues. In this study, we introduce reduced graphene oxide (rGO) recording electrodes in the format of 3-dimensional flexible membranes (rGO-3D) and 2-dimensional thin films (rGO-2D) for long-term and acute recordings, respectively. The rGO electrodes supported the functional development of cultured primary neurons and displayed good recording capabilities similar to conventional glass pipette and Pt ball electrodes in ex vivo and acute in vivo experiments. In vivo biocompatibility studies demonstrated the migration of neural processes onto the rGO-2D surface and within the rGO-3D electrodes, with the latter forming an intimate interpenetrating network. This study not only generates new knowledge to balance conductivity and porosity of rGO coatings but also provides in-depth evaluation of the physical and biological properties of such interfaces.

Concept of a Novel Glass Ionomer Restorative Material with Improved Mechanical Properties.

The objective of this study was to transfer the concept of ductile particle reinforcement to restorative dentistry and to introduce an innovative glass ionomer material that is based on the dispersion of PEG-PU micelles. It was hypothesized that reinforcing a conventional glass ionomer in this way increases the flexural strength and fracture toughness of the material. Flexural strength and fracture toughness tests were performed with the novel reinforced and a control glass ionomer material (DMG, Hamburg, Germany) to investigate the influence of the dispersed micelles on the mechanical performance. Transmission electron microscopy was used to identify the dispersed micelles. Fracture toughness and flexural strength were measured in a 3-point-bending setup using a universal testing machine. Before performing both tests, the specimens were stored in water at 37 °C for 23 h. The fracture toughness (MPa∙m0.5) of the novel glass ionomer material (median: 0.92, IQR: 0.89-0.94) was significantly higher than that of the control material (0.77, 0.75-0.86, p = 0.0078). Significant differences were also found in the flexural strength (MPa) between the reinforced (49.7, 45.2-57.8) and control material (41.8, 40.6-43.5, p = 0.0011). Reinforcing a conventional glass ionomer with PEG-PU micelles improved the mechanical properties and may expand clinical applicability of this material class in restorative dentistry.

Perovskite-Coated Thermochromic Transparent Wood: A Novel Material for Smart Windows in Energy-Efficient and Sustainable Buildings.

Transparent wood (TW) has emerged as a sustainable alternative to conventional glass as an energy-efficient window glazing material owing to its exceptional optical transparency and superior mechanical and thermal performances. However, it is challenging to develop the TW-based color-switching smart windows with both high optical performance and mechanical strengths. In this work, an optically switchable and mechanically robust perovskite-coated thermochromic transparent wood (PTTW) is developed for use as smart windows to achieve an effective solar modulation and thermal management. PTTW exhibits a substantial solar modulation ability Δτsol of 21.6% and a high clear-state luminous transmittance τlum of 78.0%, which enable an efficient thermal regulation while ensuring high visual clarity. PTTW also offers enhanced mechanical properties (i.e., tensile strength σtens = 71.4 MPa and flexural strength σflex = 93.1 MPa) and improved thermal properties [i.e., thermal conductivity K = 0.247 W/(m·K) and heat capacity C = 1.69 J/(g·°C)] compared to glass-based smart windows, as well as excellent performance stability (i.e., 200 heating-cooling cycles), manifesting its applicability in real building scenarios. In addition, PTTW also demonstrates a remarkable thermal-regulating performance (i.e., 5.44 °C indoor air temperature regulation) and an energy-saving potential (i.e., 12.9% heating, ventilation, and air conditioning energy savings) in Hong Kong. Overall, this study contributes to the progression toward energy-efficient and sustainable buildings.

High-performance thermochromic YSZ/[formula omitted]/YSZ coatings for energy-saving smart windows

The reversible semiconductor-to-metal transition of vanadium dioxide (VO2) makes VO2-based coatings a promising candidate for thermochromic smart windows, reducing the energy consumption of buildings. We report on a scalable sputter deposition technique for fast preparation of strongly thermochromic YSZ/V0.986W0.014O2/YSZ coatings, where YSZ denotes Y-stabilized ZrO2, on conventional soda-lime glass at a relatively low substrate surface temperature (350 °C) and without any substrate bias voltage. The thermochromic V0.986W0.014O2 layers and the antireflection YSZ layers were deposited using a controlled high-power impulse magnetron sputtering of a single V–W and Zr–Y target, respectively. A coating design utilizing a second-order interference in the YSZ layers was applied to increase both the integral luminous transmittance (Tlum) and the modulation of the solar energy transmittance (ΔTsol). We present the phase composition (X-ray diffraction) and microstructure (high-resolution transmission electron microscopy) of the coatings and their optical properties (spectrophotometry and spectroscopic ellipsometry). The YSZ/V0.986W0.014O2/YSZ coatings exhibit a transition temperature of 33–35 °C with Tlum = 64.5% and ΔTsol = 7.8% for a V0.986W0.014O2 thickness of 37 nm, and Tlum = 46.1% and ΔTsol = 13.2% for a V0.986W0.014O2 thickness of 67 nm. The results constitute an important step to a cost-effective and high-rate preparation of large-area thermochromic VO2-based coatings for future smart-window applications.

High-tolerance nickel metalized glass gas electron multiplier: development and performance evaluation

Micro-patterned gas detectors (MPGDs) are an important type of gaseous detector that can amplify and detect a small amount of electric charge generated by the interaction between radiation and gas. These detectors have high gain and high spatial resolution, making them useful in various applications ranging from high energy physics to medical instrumentation. However, one of the most widely used MPGDs, Gaseous Electron Multipliers (GEMs), may often experiences electrical discharges due to excessive electric field in the small space, which reduces their durability. To address this issue, we previously have developed a new type of GEM that uses glass as the insulator instead of conventional materials. Our glass GEM demonstrated excellent gas gain and energy resolution characteristics. In this work, we used nickel as the electrode, which has a higher melting point than copper and showed higher durability against arc discharges. Moreover, the nickel glass GEM performed comparably to conventional Cu-based glass GEMs in evaluation using radiation isotopes. Our findings suggest that our new glass GEM with nickel electrodes is a promising solution to the durability problem of conventional GEMs. This could lead to improvements in the performance and longevity of MPGDs, which could have significant implications for various applications in the fields of physics, engineering, and medicine.

Superaligned carbon nanotube film/quartz fiber composites towards advanced lightweight lightning strike protection

Due to poor electrical conductivity, carbon fiber-reinforced plastic (CFRP) is easily damaged by lightning strikes. In this paper, highly conductive superaligned carbon nanotube films (SA-CNTFs) and new isolation layers (quartz fibers) were combined to fabricate advanced lightweight lightning strike protection (LSP) composites. We verified that the isolation layer indeed has an LSP effect and demonstrated for the first time that quartz fibers are a better alternative isolation layer material candidate than conventional glass fibers due to their high thermal resistance. The “complementary effect” between the conductive layer and the isolation layer is revealed. The preliminarily optimized laminate composites made of SA-CNTF/quartz fiber can sustain 100 kA simulated lightning strike. Compared with typical CNT-based LSP laminate samples made of buckypaper/Boron Nitride/epoxy layer or SA-CNTF/glass fiber, the weight can be reduced by at least ∼30% and ∼38%, respectively.

Depletion of two-level systems in highly stable glasses with different molecular ordering

Recent findings of structural glasses with extremely high kinetic and thermodynamic stability have attracted much attention. The question has been raised as to whether the well-known, low-temperature “glassy anomalies” (attributed to the presence of two-level systems [TLS] and the “boson peak”) persist or not in these ultrastable glasses of much lower configurational entropy. To resolve previous contradictory results, we study a particular type of ultrastable glass, TPD, which can be prepared by physical vapor deposition in a highly-stable state with different degrees of layering and molecular orientation, and also as a conventional glass and in crystalline state. After a thorough characterization of the different samples prepared, we have measured their specific heat down to 0.4 K. Whereas the conventional glass exhibits the typical glassy behaviour and the crystal the expected Debye cubic dependence at very low temperatures, a strong depletion of the TLS contribution is found in both kinds of ultrastable glass, regardless of their layering and molecular ordering.