Ea Decrease Research Articles

Influence of TiO2 addition on the Mg4Nb2O9 ceramic phase and its application in the radiofrequency region

In this work, the dielectric properties of (1-x) Mg4Nb2O9 – (x) TiO2 composite ceramics in radiofrequency and the microwave region were evaluated. X-ray diffraction demonstrated that Mg4Nb2O9 (MNO) reacted with TiO2 resulting in the formation of new crystalline phase Mg5(Nb0.625Ti0.375)4O15. Complex Impedance Spectroscopy (CIS) analysis was realized to analysis the electrical properties of materials, whereas was observed that activation energy (Ea) decrease from 1.64 to 1.37 eV with an increase in TiO2 concentration. Temperature capacitance coefficient (TCC) was obtained and showed that at different frequencies all materials could be used as Class 1 ceramic capacitors according to EIA RS-198. In the Microwave region, MNO – TiO2 demonstrated ε’r between 12.07 (MNO) and 14.08 (MNO18T), tan δ values varying of 2.64 × 10-4 (MNO) up to 5.92 × 10−4 (MNOT14). Regarding the temperature coefficient of resonant frequency (τf) was observed that the values decreased with the increase in TiO2, with the value closest to zero being that of pure MNO (τf = −27 ppm.°C−1). The results presented show that materials evaluated could be utilized in devices that can be act in radio frequency (RF) and microwave (MW) regions.

Lateral impact behaviour of CCFT columns with spherical-cap gap imperfection: Numerical modelling and design method

To clarify the influence of gap imperfection on the impact behaviour of the concrete-filled steel tube (CFT) column, this paper performs numerical modelling on the mechanical responses of the circular CFT columns holding spherical-cap gaps (CCFT-SG) under lateral impact load. The effects of gap ratio, axial compression ratio, impact position, diameter/thickness ratio, boundary condition and material strength on the energy dissipation (Ea), the maximum (Fm) and equivalent impact forces (Feq), the peak (δm) and residual lateral deflections (δr) are analyzed after establishing and validating the finite element (FE) model. The typical failure pattern, time-history curve and contact response between the tube and concrete of the laterally impacted CCFT-SG column are revealed as well. The result declares that the overall failure morphology of the CCFT-SG column imposed with lateral impact showing as overall bending, is similar to that of the common CFT column, but distinct local depression is obtained because of the existence of spherical-cap gaps. With the gap ratio increasing, the Feq, Fm and Ea decrease gradually, while the δm and δr rise slowly. The calculation formulae for predicting the dynamic impact force and resistance of the CCFT-SG column are presented and validated against the existing test and numerical results.

Synthesis, crystal structure of 2,4-dihydroxybenzoic acid lead and its catalytic decomposition effect on AP and RDX

2,4-Dihydroxybenzoic acid lead (β-Pb) was synthesized and its single crystal structure was reported firstly. β-Pb crystallizes in monoclinic system with space group of C2/m and crystal parameters of a=17.888(3) Å, b=4.8790(8) Å, c=21.408(4) Å, β=100.258(5) °, Z=2, V=1838.5(5) Å3, μ=12.213 mm−1, F(000) = 1000.0 and Dcalc = 1.920 g/cm3. 2,4-Dihydroxybenzoic acid presents a monoacid form only, two different coordination forms of Pb2+ exist in crystal structure of β-Pb, and the two phenolic hydroxyl groups all do not involved in coordination with lead ions. The thermal decomposition of β-Pb and its catalytic effect on thermal decomposition of AP and RDX were explored. For AP, the low-temperature decomposition temperature (LTT) and high-temperature decomposition temperature (HTT) decrease by 30.4 °C and 31.3 ℃ with the addition of β-Pb, and their apparent activation energies (Ea) decrease by 44.4 kJ/mol and 31.6 kJ/mol, respectively. For RDX, the thermal decomposition temperature and Ea decrease by 11 °C and 110.7 kJ/mol respectively, after the addition of β-Pb. β-Pb shows excellent catalytic decomposition effect on AP and RDX.

A baseline study on the impact of nanoplastics on the portals of entry of xenobiotics in fish

Mediterranean waters are particularly vulnerable to plastic pollution, with plastic particles concentrations comparable to those found in oceanic gyres. This work aimed to assess the impact of polymethylmethacrylate nanoplastics (PMMA-NPs) on the most important mucosal barriers of the gilthead seabream (Sparus aurata), a highly consumed fish species in the Mediterranean area. Fish were waterborne exposed to NPs (0.001–10 mg/L) for 24 and 96 h, and biochemical parameters associated with oxidative status (total oxidative status and total antioxidant capacity) and immune function (adenosine deaminase, ADA, acetylcholinesterase activity, AChE, and esterase activity, EA) were assessed in gills, intestine, and skin. In intestine, PMMA-NPs led to oxidative status alterations and decreased ADA and EA. In gills, PMMA-NPs induced EA decrease and AChE activity increase. Total protein values were significantly increased in skin. Overall, more alterations were observed in intestine, suggesting it may be one of the most affected tissues by exposure to NPs.

Characterization of Zr‐Doped Ceria and Sr‐Doped La−Mn Perovskites as Redox Intermediates for Solar Chemical‐Looping Reforming of Methane

Zr‐doped ceria and Sr‐doped lanthanum manganese perovskites are investigated as candidate redox materials for the chemical‐looping reforming of methane to produce syngas. Herein, the effect that these compositions have on syngas selectivity, partial oxidation of methane (POM) rate, and yield in the temperature range of 800−1000 °C is probed. POM reaction rates increase when using 10% Zr‐doped ceria (CZO10) compared with pure ceria at all conditions, but the yields are generally less except at 800 °C. In the case of (La0.65Sr0.35)0.95MnO3 (LSM35), POM yields are equal to or greater than ceria under all conditions investigated. For all materials, selectivity to syngas during POM is relatively high and typically above 85%. However, selectivity of CZO10 and LSM35 is lower than ceria, likely because of their lower reduction enthalpies and more accessible surface oxygen. This is validated by demonstrating improvements in POM selectivity by suppressing the oxidation extent; in this case, there is no observable H2O or CO2 formation. POM rates increase and activation energy (Ea) decreases for all materials following oxidation with O2 versus CO2. Ceria and CZO10 Ea decrease from about 225 to <50 kJ mol−1 and LSM35 from 150 to 100 kJ mol−1.

Electrochemical performance and thermal stability of lithium ion batteries after immersion

In this work, electrochemical performance, aging mechanisms and thermal stability of LIBs after immersion were analyzed. The results show that corrosion increases with the increasing electric potential, NaCl concentration and immersion time. Moreover, capacity fading occurs after immersion, decreasing the lifespan of the battery. This effect is mainly caused by the loss of active material (LAM). With increasing NaCl concentration, capacity fading increases and battery lifespan decreases. The activation barriers (Ea) and the onset temperature of exothermic reactions (TOER) of cells initially increases and then decreases. The thermal stability of cells dramatically decreases after immersion in highly-concentrated NaCl solutions, which has higher onset temperature of thermal runaway (TOTR) and lower maximum temperature (TMax). With the increasing immersion time, the TOER initially decreases and then increases, TOTR increases, while TMax and Ea decrease.

PREPARATION, CHARACTERIZATION AND STUDIES OF PHYSICOCHEMICAL AND BIOLOGICAL PROPERTIES OF DRUGS COATING LACTOSE IN FLUIDIZED BEDS

Objective: Study physicochemical properties and activity of biotechnological drugs coating lactose particles in fluidized beds for the development of a prospective approach of their identification.
 Methods: Lactose monohydrate as pharmaceutical excipient; affinity-purified polyclonal rabbit antibodies to recombinant human interferon-gamma as a drug substance; Pilotlab fluid bed apparatus was used for lactose powder saturation with solutions of pharmaceutical substances to the point of granulation (pelletizing); inverse light scattering method (2D-LS) for analysis of micron vibrations frequency spectra of samples surfaces for light intensity distribution in time by values of d1, d2, d3 primary descriptors; low angel and dynamic laser light scattering (LALLS, DLS) methods for distribution of lactose-water (LW) supramolecular complexes into volume fractions (micron "size spectra"), using the Master Sizer 2000 instrument and Zeta Sizer Nano ZS instrument in the nanoscale; Spirotox method for research of biological activity to determine the activation energy (Ea) values of cell death in solutions of tested samples.
 Results: Changes in 2D-LS scattering time on sample surfaces, described by topological descriptors, made it possible to clearly differentiate the intact lactose from fluidized samples by specific corridors in coordinates di=F(t). The calculated activation energy (Ea) values of cell biosensor death process in solutions of drugs coating lactose allow to characterize the biological activity of it in the initial (by Ea increase) and activated state (by Ea decrease) after the creation of intra-laboratory transmucosal conditions. A unique dimensional spectrum of LW complexes in the nanoscale range was obtained by DLS. The differences between samples in the distribution of LW complexes in the size range from 1 µm to 125 µm was showed by LALLS.
 Conclusion: The developed approach, including Сhemometrics, laser and biotesting methods can be used for qualitative the analysis tasks as well as for analytical control of the fluidization process in cases where identifiable pharmaceutical substances are not distinguishable by traditional analytical methods.

Effects of Defective Boron Nitride Additives on Lithium-Ion Conductivity and Hydrogen-Desorption Properties of LiAlH4

The lithium-ion conductivity and hydrogen-desorption properties of lithium alanate (LiAlH4)/boron nitride (BN) composites were investigated. The effects of boron nitrides with different structures (hexagonal (h-BN), turbostratic (t-BN), and cubic (c-BN)) on the properties were demonstrated. Compared with milled LiAlH4, the ion conductivity was improved in the h-BN and t-BN composites. Among the composites, the t-BN composite showed the highest conductivity and lowest activation energy (Ea) for ion conduction. In the 40 wt % t-BN composite, the conductivity at 80 °C reached as high as 1.1 × 10–3 S cm–1. Impedance plots that correspond to the interfacial conductivity were observed, which implies the appearance of LiAlH4/t-BN interfacial ion conduction. Ball-milling of LiAlH4 with BN caused the partial replacement of aluminum with boron to form LiBH4 phase, which would cause the Ea decrease. The LiAlH4 melting and hydrogen-desorption temperature decreased in the t-BN composite. In the c-BN composite, a large amount of stainless steel impurity during ball-milling caused desorption without melting. This study suggests that the addition of defective boron nitride like t-BN can be a useful strategy to improve the lithium-ion conductivity of complex hydrides. The t-BN additive effects on the hydrogen-desorption properties, which are different from transition metal catalysts, were also demonstrated.

Ventricular-arterial coupling parameters and its prognostic value in patients with decompensated heart failure

Aim. To assess ventricular-arterial coupling (VAC) parameters and their prognostic value in patients with decompensated heart failure (HF).Material and methods. VAC parameters were evaluated upon admission using two-dimensional echocardiography in 355 patients hospitalized with decompensated HF. VAC was expressed as the ratio between arterial elastance (Ea) and end-systolic LV elastance (Ees). The optimal VAC range was considered 0,6-1,2. Parameters of left ventricular (LV) efficacy were calculated using the appropriate formulas. Differences were considered significant at p<0,05.Results. The median values of Ea, Ees and VAC were 2,2 (1,7;2,9) mmHg/ml, 1,8 (1,0;3,0) mmHg/ml and 1,32 (0,75;2,21) respectively. In 63% of patients, VAC disorders were detected: 55% of patients had VAC >1,2 (predominantly patients with HF with reduced ejection fraction (HFrEF)-79%), 8% of patients had VAC <0,6 (all patients with HF with preserved ejection fraction (HFpEF)). Normal VAC was observed in 78%, 42%, and 1% of patients with HFpEF, HF with mid-range EF and HFrEF, respectively. There was significant correlation between Ea/Ees ratio and levels of NTproBNP (R=0,35), hematocrit (R=-0,29), hemoglobin (R=-0,26), pulmonary artery systolic pressure (PAPs) (R=0,18), dimensions of left atrium (R=0,32) and right ventricle (RV) (R=0,32). After 6 months, rehospitalization with decompensated HF was recorded in 72 (20,3%) patients, 42 (11,8%) patients died. Ea decrease <2,2 mmHg/ml and PAPs increase >45 mmHg increased the risk of rehospitalization with decompensated HF and all-cause mortality 2,5 and 3,7 times, respectively.Conclusion. Impaired VAC was diagnosed in 63% of patients with decompensated HF. However, the increased risk of all-cause mortality and rehospitalization with decompensated HF over the 6 months was associated with Ea decrease <2,2 mmHg/ml and PAPs increase >45 mmHg.

Kinetic Performance of Ascorbic Acid Degradation on Local Lemon Juice using Different Packaging Materials at Storage

Kinetic of ascorbic acid dissolution of vitamin ( C ) in Lemon juice 10 Brix packaged in glass and plastic bottles stored at 20,30 and 40 °C for four months have been investigated .The results showed that increasing temperature and period storage caused decreasing in ascorbic acid content and increasing nonenzymatic browning. The stability of ascorbic acid and reduced of nonenzymatic browning was better in the packed in glass bottles. The results of ascorbic acid degradation kinetic parameter showed that the order of the reaction is First and there was an increasing in rate constant(K)in the case of increasing of the storage temperature and in the samples of glass bottlesk.The activation energy (Ea) decrease in plastic bottles. It was found that the shelf life of samples decreased with increasing the storage temperature .We got in this study the shelf life of ascorbic acid from 0 to 50 0C.

Synergistic effects during the co-pyrolysis and co-gasification of high volatile bituminous coal with microalgae

In this work, the co-pyrolysis and co-gasification of Nannochloropsis sp. microalgae (NM) and Colombian bituminous coal (CC) were performed in order to evaluate potential synergistic effects and the kinetic parameters, which are essential for advancing the co-utilization. The effect of the share of feedstock, microalgae and coal, on the co-pyrolysis and co-gasification behavior was studied under different heating rates and temperatures. There were synergistic effects between the two fuels during their co-pyrolysis process, especially for that mixture containing 50 wt% of microalgae. At conversion levels < 25 wt%, the activation energy (Ea) was found to be lower than the individual microalgae, 143 and 170 kJ/mol, respectively. Despite the acid leaching pre-treatment (NM-ac) showed a positive effect on the microalgae pyrolysis kinetics for conversion values < 60 wt%, the trend was inverted at higher conversions, due to the removal of alkali species form microalgae ash, which also slowed the CC/NM gasification. However, ash removal can potentially reduce operational issues related to presence of Cl and Na. Both synergistic and inhibiting effects were observed in the co-gasification experiments. Synergistic effect at temperatures higher than 800 °C was due to the microalgae high Na content that promoted coal char gasification, resulting in an Ea decrease for the coal from 189.9 to 146.1 kJ/mol. This reduction was higher to that expected if both fuels would behave according to the mixtures additive law (159.1 kJ/mol), Inhibiting effect at 750–800 °C can be linked to lower presence of Na on char surface and lower transformation of NaCl in gasification active species.

Optical absorption and heating rate dependent glass transition in vanadyl doped calcium oxy-chloride borate glasses

Some important results pertaining to optical and thermal properties of vanadyl doped oxy-halide glasses in the chemical composition CaCl2–CaO–B2O3 are discussed. These glasses have been prepared by conventional melt quench technique. From X-ray diffraction (XRD) profiles the amorphous nature of the doped glasses has been confirmed. The electronic polarizability is calculated and found to increase with increase in chloride content. The optical absorption spectra have been recorded in the frequency range of 200–3200nm. Recorded spectra are analyzed to evaluate cut-off wavelength (λcut-off), optical band gap (Eg), band tailing (B), Urbach energy (ΔE) and refractive index (n). Thermal analysis has been carried out for the prepared glasses at three different heating rates viz. 5, 10 and 20°C/min. The glass transition temperature (Tg) along with thermal activation energy (Ea) corresponding to each heating rate are evaluated from differential scanning calorimetry (DSC) thermographs. It is found that Ea decrease and Tg increase with increase in heating rate. The variation in Tg is also observed with the substitution of calcium chloride in place of calcium oxide. The increasing and higher values of Ea suggest that prepared glasses have good thermal stability. Variation in Tg and Eg suggests that Cl− anions enter into the voids of borate network at low concentrations (<5.0%) and contribute to the network formation at high concentration (>5.0%).

Preparation and characterization of nanocomposite films by hybrid cationic ring opening polymerization of glycidyl-POSS

Epoxy-polyhedral oligomeric silsesquioxanes (G-POSS) monomers were synthesized from 3-glycidyloxypropyl-trimethoxysilane (GTMS) by hydrolytic condensation. The G-POSS-containing nanocomposite film was prepared by hybrid cationic ring-opening polymerization from G-POSS and GTMS. The curing reaction kinetics, dynamical mechanical properties, thermal degradation properties and morphological structures of G-POSS/GTMS system were investigated by non-isothermal DSC, dynamic mechanical analysis (DMA), TGA, AFM and SEM. The results show that the curing reaction activation energy Ea decrease when GTMS is added into the reaction system, and the curing reaction kinetics can be simulated by the Šesták–Berggren (S–B) model. DMA and TG analysis results show that the glass transition temperature Tg and initial thermal decomposition temperature Tid of materials is 4 and 65 °C higher than pure polymerized G-POSS, respectively, when the content of GTMS is 2 wt%. AFM analysis shows that the membrane surface of pure polymerized G-POSS has uniform distribution of less than 1.76 nm high protrusion. SEM analysis shows that have uniform spherical particle distribution on the membrane surface with about 20–25 nm diameter.

Effect of (CaO+MgO)/SiO2 ratio on crystallisation and properties of slag glass–ceramics

Metallurgical slag, quartz sand and coal fly ash were used as the raw materials for preparation of glass–ceramics according to their compositions and characteristics. Under different mole ratios of (CaO+MgO)/SiO2, the crystallisation mechanism, microstructure and main mechanical properties of glass–ceramics were systematically investigated through differential thermal analysis, X-ray diffraction, scanning electron microscopy, mechanical and chemical properties test. The results indicate that MgO plays the same role of CaO. The crystallisation activation energy Ea and crystallisation temperature Tp decrease as the increase in (CaO+MgO)/SiO2 ratio. It is found that when (CaO+MgO)/SiO2 ratio is 0·64 and sintering lasts for 1 h at 996°C, main phase of diopside can be obtained with the best mechanical properties and chemical durability, such as bending strength 110 MPa, microhardness 6·5 GPa, mass loss rate of 0·25 and 0·1% as acid resistance and alkali resistance respectively.

Hybrid free radical-cationic thermal polymerization of methylacryloylpropyl-POSS/epoxy resins nanocomposites

Methylacryloylpropyl polyhedral oligomeric silsesquioxanes (MAP-POSS) was prepared from methylacryloyloxypropyl three methyl silane (MAPTMS) by hydrolytic condensation. The hybrid cationic thermal polymerization of MAP-POSS with bisphenol-A epoxy resin (E-51) using diphenyliodonium fluoride-borate (DPI·BF4) as a cationic initiator and benzoyl peroxide (BPO) as co-initiator were investigated by the DSC and FTIR. The dynamic mechanical properties of MAP-POSS/E-51 nanocomposites were characterized by DMA. The results showed that polymerization of MAP-POSS/E-51 are the double hybrid free radical/cationic polymerization. The hybrid cationic polymerizing mechanism and curing kinetics could be simulated by the autocatalytic Sestak-Berggren(S-B) model. The cationic ring-opening average activation energy E a decrease with added MAP-POSS, when 0, 2, 6, and 10 wt.% MAP-POSS were added into reaction system, the curing reaction E a of sample is 96.53, 95.16, 93.98, 89.15 kJ/mol, respectively. The glass transition temperature T g of 8 wt.% MAP-POSS containing sample is 175.6 °C, which is 6.1 °C higher than the pure E-51 resin.

Structural, electronic and charge transfer studies of dianthra[2,3-b:2′,3′-f]thieno[3,2-b]thiophene and its analogues: Quantum chemical investigations

The ground state structures of dianthra[2,3-b:2′,3′-f]thieno[3,2-b]thiophene, its derivatives and analogues have been optimized at B3LYP/6-31G** level of density functional theory. The computed geometrical parameters are in good agreement with the experimental data. The decrease in the bond length has been observed in the sequence, SC>BC>OC. The substitution of F and N has no effect to lengthen or shorten the nearest CC or central CC, SC, OC, BC bond lengths. The highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) of all the molecules are spread over the whole pi-conjugated backbones with similar character. The HOMOs displays bonding character within each unit while the LUMOs exhibit the antibonding character. By substituting the boron (3), fluoro and nitrogen (4–6) make the LUMOs energy levels lower resulting higher electron mobility. The values of IPv/a and EAv/a increase from 1 to 6 except in 2 where EA decrease but the effect is not so significant. The high EAs of 3 and 6 revealed that these molecules would be more suitable for generating free electron. The positive correlation between EAv and the LUMO levels has been observed. The 3 and 6 would be better as n-type materials having EAs close to 3.0eV. The electron reorganization energies for 1, 2, 4 and 5 are higher than hole reorganization energies while λe are less than those of λh for 3 and 6. In the last step, we have simulated and successfully regenerated the crystal structure of parent molecule by MM energy minimization approach.

Study of the Cure Reaction of Epoxy Resin Diglycidyl Ether of Bisphenol-A (DGEBA) with Meta- Phenylene Diamine

The cure process of epoxy resin diglycidyl ether of bisphenol-A (DGEBA) with aromatic amine (m-PDA) as curing agent was studied by means of differential scanning calorimetry (DSC) Perkin Elmer Pyris 6, at ratio (15 phr). Isothermal DSC measurements were conducted between 80 and 110 oC, at 10 oC intervals. The maximum degree of cure at isothermal cure temperature 110 oC was 0.9. The isothermal cure process was simulated with Kamal modifier with diffusion model, the model agrees well with the experimental data. For dynamic cure process, the activation energy was determined by two methods. One was based on Kissinger and Ozawa approach, given only one activation energy for the whole curing process. There was a slightly difference between the obtained activation energy and pre-exponential factor, 63.6 and 70.7 kJ mol-1 respectively. Another method was based on isoconversional, given activation energy at any conversion, and observed the Ea decrease with increment conversion (67-63) KJ/mol.

Chemical Modification As a Versatile Tool for Tuning Stability of Silica Based Mesoporous Carriers in Biologically Relevant Conditions

A comparative study of the degradation in a model phosphate buffered saline (PBS) medium of mesoporous mixed silica–zirconia oxides and hybrid organosilica materials is reported, and their thermodynamic and kinetic stability are discussed. Thin film morphology was used to monitor the degradation rates of all these materials for the first time directly in liquid and undersaturated medium. The introduction of zirconium centers in mesoporous materials strongly inhibits degradation and allowed the self-limitation of soluble silica concentration in the immediate environment of the vector. This avoids renucleation of potentially toxic silica small nanoparticles with uncontrolled surface chemistry in the release medium. Chemical modifications (hybridation or zirconia doping) of mesoporous silica allow the fine-tuning of its degradation from hours to days. Methylated thin films are highly stable when the functionalization ratio is high (50%). The hybridation by mercaptopropyl and aminopropyl moieties can be successfully performed without any high thermal treatment, allowing not only slowing down silica dissolution but also opening the possibility to introduce in one-pot other thermally fragile molecules into the vector. Dissolution rates K measured for the first time at different biologically relevant temperatures follows an Arrhenius law: K = KoExp(−Ea/RT). Stabilities of these chemically modified silicas are mainly associated with a strong decrease of the pre-exponential factor K0 of modified silicas. Counterintuitively, activation energies Ea decrease with increasing the hybrid/silica or the zirconia/silica ratios.

Structure and properties of the aluminum borates Al(BO2)n and Al(BO2)n−, (n = 1–4)

The geometrical and electronic structures of Al(BO(2))(n) and Al(BO(2))(n)(-) (n = 1-4) clusters are computed at different levels of theory including density functional theory (DFT), hybrid DFT, double-hybrid DFT, and second-order perturbation theory. All aluminum borates are found to be quite stable toward the BO(2) and BO(2)(-) loss in the neutral and anion series, respectively. Al(BO(2))(4) belongs to the class of hyperhalogens composed of smaller superhalogens, and should possess a large adiabatic electron affinity (EA(ad)) larger than that of its superhalogen building block BO(2). Indeed, the aluminum tetraborate possesses the EA(ad) of 5.6 eV, which, however, is smaller than the EA(ad) of 7.8 eV of the AlF(4) supehalogen despite BO(2) is more electronegative than F. The EA(ad) decrease in Al(BO(2))(4) is due to the higher thermodynamic stability of Al(BO(2))(4) compared to that of AlF(4). Because of its high EA and thermodynamic stability, Al(BO(2))(4) should be capable of forming salts with electropositive counter ions. We optimized KAl(BO(2))(4) as corresponding to a unit cell of a hypothetical KAl(BO(2))(4) salt and found that specific energy and energy density of such a salt are competitive with those of trinitrotoluol (TNT).

Electron Transport in Polymer‐Derived Amorphous Silicon Oxycarbonitride Ceramics

The electron transport behavior of polymer‐derived amorphous silicon oxycarbonitride ceramics is studied by measuring their temperature‐dependent electrical conductivities. The experimental results are analyzed using theoretical models. The results reveal that the materials exhibit three conduction mechanisms: conduction in extended states, conduction in band tails, and conduction in localized states. Particularly, it is found that in a low‐temperature regime, the conduction of the materials follows a band tail hopping mechanism, rather than the previously assumed variable range hopping mechanism. The results also reveal that energy gaps such as EC−EF and EC−EA decrease with increasing pyrolysis temperature.