High Relative Stability Research Articles

Electrodeposition of Tin and Antimony-Based Anode Materials for Sodium-Ion Batteries

Tin antimonide (SnSb) is a promising alloying anode for sodium-ion batteries due to its high theoretical capacity and relative stability. The material is popular in the battery field, but, to our knowledge, few studies have been conducted on the influence of altering Sn and Sb stoichiometry on anode capacity retention and efficiency over time. Here, Sn-Sb electrodes were synthesized with compositional control by optimizing electrodeposition parameters and stoichiometry in solution and the alloys were cycled in sodium-ion half-cells to investigate the effects of stoichiometry on both performance and electrochemical phenomena. Higher concentrations of antimony deposited into the films were found to best maintain specific capacity over 270 cycles in the tin-antimony alloys, with each cell showing a slow, gradual decrease in capacity. We identified that a 1:3 ratio of Sn:Sb retained a specific capacity of 486 mAh g−1 after 270 cycles, highlighting a need to explore this material further. These results demonstrate how control over stoichiometry in Sn-Sb electrodes is a viable method for tuning performance.

Density functional study on highly energetic organic azides with empirical formula Cn(N3)m

AbstractThe structural, electronic, and thermodynamical properties of Cn(N3)m (n = 1–7) (m = 4, 6) organic azides have been investigated using Density Functional Calculations. The ground state structures of organic azides were compared with CnHm (n = 1–7) (m = 4, 6) cumulenes which shows their higher relative stability. The stability and reactivity of organic azides were analyzed by calculating the HOMO‐LUMO gap, binding energies, and harmonic frequencies of the azides. The binding energy and formation energy of Cn(N3)m (n = 1–7) (m = 4, 6) organic azides suggest their energetic stability. The structural analysis of the azide group in Cn(N3)m (n = 1–7) (m = 4, 6) organic azide shows a tendency to stabilize at a maximum separation between functional azide groups. Ionization potential, electron affinities, and global hardness have been computed for Cn(N3)m (n = 1–7) (m = 4, 6) organic azides and the odd–even alternation rule was observed. The molecular dynamic simulation performed at 300 K for 1 fs confirms organic azide's structural stability at room temperature, except for C4(N3)4, and the members of their family can be synthesized.

Determination of Ground State Structures of Snx - (x=21-35) Clusters.

In this work, an unbiased global search with a homemade genetic algorithm was performed to investigate the structural evolution and electronic properties of Snx - (x=21-35) clusters with density functional theory (DFT) calculations. All the ground-state structures for all these Snx - (x=21-35) clusters have been confirmed by the comparison of the experimental and simulated photoelectron spectra (PESs). It has been revealed that all Snx - (x=21-35) clusters are tricapped trigonal prism (TTP)-based structures consisting of two (for sizes x=21-28) or three (for x=29-35) TTP units, with the remaining atoms adsorbed on the surface or inserted between TTP units. The gradually decreasing HOMO-LUMO gaps indicate that these clusters are undergoing semiconductor-to-metal transformation. The average binding energies show that the structural stabilities of Snx - clusters are not as good as that of silicon and germanium clusters. It found that sizes x=23, 25, 29, 33 show high relative stability.

Psychological correlates of body dissatisfaction in Swiss youth over a one-year study-period.

It is well known that young individuals often report pronounced negative perceptions and attitudes towards their own body or intense fear of being not muscular enough. There is much less data available, however, on the role of psychological mechanisms on these perceptions and attitudes, such as emotion regulation difficulties, correlates of alexithymia, and appearance-related rejection sensitivity. We therefore set out to assess associations between these psychological mechanisms, and body image as well as muscle dysmorphic symptoms. Our sample was recruited as part of a larger-scale study aiming at assessing correlates of mental health (with a focus on eating disorder symptoms) in German speaking Switzerland. The first wave (T1), starting in April 2021, included 605 participants (80% female, 19.6 ± 2.5 years) who completed the online-questionnaire and were reassessed in a second wave (T2), one year later. Results indicated that at both waves, emotion regulation difficulties [DERS-SF] and appearance-based rejection sensitivity [ARS-D] were both positively cross-sectionally associated with body dissatisfaction [BSQ-8C] and muscle dysmorphic symptoms [MDDI] at the first assessment time-point and one year later at follow-up assessment. Moreover, alexithymia [TAS-20] was positively cross-sectionally associated with muscle dysmorphic symptoms at both waves. We further observed high absolute and relative level stabilities for all variables involved across the one-year study period. Even though the effects for some associations were rather small, our findings underline the relevance of such mechanisms in the development of body dissatisfaction and to a lesser extent of muscle dysmorphia symptoms over the period of one year. Additional research is necessary to replicate these findings in other youth samples.

Discovering SnB7-: a half-sandwich structure with double aromaticity and pathways to molecular machines.

Numerous boron-based molecular fluxional models, such as the Wankel motor, tank treads B11- and B10C, and the Earth-Moon system Be6B11-, have been widely recognized for their potential to develop molecular machines. From a series of tin-doped boron clusters SnBn- (n = 5-14), the half-sandwich structure SnB7- is found to possess high relative energy stability, and a HOMO-LUMO gap of 4.33 eV. This structure exhibits valence electron orbitals reminiscent of σ-π double aromatic compounds. The incorporation of tin effectively fills the doubly vacant π orbitals of its parent triplet B7-, thereby enhancing both magnetic shielding capabilities and range. Thermal bath tests demonstrate its significant dynamic stability, as the kinetic energy provided by thermal baths below 3800 K remains insufficient to disrupt its inherent elasticity. Additionally, transition state searches and intrinsic reaction coordinate analyses confirm that the tin atom migrates from the centre to the edge of the boron ligand surface, a phenomenon that can be observed in high-temperature thermal bath simulations. This fluxional behaviour provides insights for constructing novel molecular machine models.

Thermite-for-Demise (T4D): Experimental analysis of heat transfer principles and preliminary sizing of an application

The use of exothermic reactions to aid satellite demise during re-entry is under investigation. An energetic material, if stored on board, could passively ignite thanks to the heat load experienced by the spacecraft during re-entry, and ease its complete ablation. Thermites are good candidates for this application because of their high energy density and relative stability. Their effectiveness is strictly related to the heat transfer efficiency between the ignited powder and its confining vessel. Experiments in non-relevant environment were conducted for Al+Fe2O3 thermite to quantify this value. The average heat transfer efficiency was quantified at 60%, with respect to the theoretical heat release of the mixture. A novel numerical model implementing a T4D application, named TRANSIT (TRANsatmosferic SImulation Tool), is presented and verified with respect to two commercial software packages. In particular, literature data for SAM and dedicated simulations for SCARAB have been used in this phase. TRANSIT is then employed to preliminarily size a thermite charge to aid spacecraft demise during re-entry for three simple re-entering objects. A genetic algorithm is employed to optimize the thermite to spacecraft mass ratio, assuring complete demise.

Theoretical study on structural evolution, photoelectron and vibrational spectra, and thermochemistry properties of neutral, anionic and di-anionic titanium-doped tin (TiSnn0/−/2− (n = 4–17)) nanoalloy clusters

The structural evolution, chemical stability, electronic and vibrational properties, as well as charge transfer and bonding character of TiSnn0/−/2− (n = 4–17) clusters have been performed with density functional theory calculations using ABCluster search technique. Structurally, it is found that the growth patterns prefer three kinds of absorbed stages from polygonal bipyramidal configuration for n = 4–6, to absorbing additional Sn on the adjacent surfaces of pentagonal bipyramid unit from n = 7–12, and finally to the TiSn130/−/2− cluster as the first foundational architectures, of which the encapsulated cage structure is formed when n = 11. The simulated PES spectra agree with available experiments. More interestingly, the neutral TiSn16 cluster not only possesses the high thermodynamic and relative stability but also preferable photochemical reactivity, that can be further explained by superatom features and delocalized multi-center bonds (AdNDP), while the strong p-d hybridization between Ti atom and Sn unit plays an important role in the stabilities of clusters, making it as the most suitable building units. In addition, the UV–Vis absorption spectra of TiSn16 are discussed, and the main transitions of crucial excited states are analyzed in detail. The Infrared and Raman vibrational characteristic peaks of all these neutral and charged species are properly assigned, of which the TiSnn0/−/2− (n = 10–17) clusters possess degenerating deformation mode of Ti atom wagging in Sn cage framework (Infrared active) and breathing mode of Sn cage framework (Raman active). All these findings will provide a further understanding for the nanoalloy cluster as the most suitable building block with further development as a potential optoelectronic material.

Experimental stability investigation of different water-in-jojoba biodiesel emulsions

Investigating the stability of water in biodiesel emulsion fuels during storage and engine operation is crucial to consider for marketing processes. This study examines the stability of water-in-Jojoba biodiesel (WJBD) emulsion that is stabilized using three commercially available surfactants, Span-80 (HLB 4.3), Tween-80 (HLB 15), Triton X-100 (HLB 13.5). The investigation involves varying the composition of the emulsions by adjusting factors such as the hydrophile lipophile balance (HLB), surfactant concentration, water concentration, mixing speed, and mixing duration, and study their effects through a bottle test. Stable emulsions are studied by bright field optical microscopy, constant shear test, and thermal loop rheology test. The research reveals that Tween-80 (HLB 15) and Span-80 (HLB 4.3) effectively yield emulsions with high relative stability. Specifically, at 5 (v%) water concentration, emulsions prepared with Tween-80 (HLB 15) demonstrate the formation of water droplets as small as 3.88 µm. Additionally, emulsions at various water concentrations are thoroughly studied. Over time, phase separation is studied by microscopic images and showed minimal coalescence after the first day for the emulsions that showed promising stability in the bottle test. To further assess the stability, the stable emulsions undergo continuous shear test, wherein a consistent pattern of stable viscosity is observed as time passed. Moreover, the thermal loop test showed minimal change in the relative microstructure of the emulsion, where the difference in the storage modulus and the loss modulus didn’t exceed 15 % and 5 %, respectively. Understanding the change in microstructure, droplet sizes, and how the emulsions behave under certain shear stresses is critical for practical applications of this fuel. Through comprehending the factors that influence the emulsion stability, this study contributes valuable insights for the successful storage and engine operation of the WJBD.

Exploration of Coumarin Derivative: Experimental and Computational Modeling for Dipole Moment Estimation and Thermal Sensing Application.

The Optical properties of the FBTC (1-((4-((5-chlorobenzo[d]oxazol-2-ylthio)methyl)-1H-1,2,3-triazol-1-yl)methyl)-3H-benzo[f]chromen-3-one) molecule were studied experimentally and theoretically. The spectra of absorption and fluorescence were recorded in various solvents to explore their Solvatochromic behavior and dipole moment at room temperature. To determine the ground and excited state of dipole moment experimentally and theoretically, we employed different Solvatochromic techniques, including microscopic solvent polarity functions developed by Lippert, Bakhshiev, Kawaski-Chamma-Viallet, and Reichardt's, as well as density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. The stability of the excited state dipole moment in FBTC is higher. Using prime functional, FBTC was optimized in its ground state, and its HOMO (Highest Occupied Molecular Orbital) and LUMO (Lowest Unoccupied Molecular Orbital), energies were estimated. These values were then compared with those obtained through cyclic voltammetry. Based on the HOMO and LUMO values given, we calculated the global reactivity parameter and energy gap, which was found to be low at 3.77eV. This study also includes an estimation of electron absorption energies and oscillator strength. Natural population analysis (NPA), Milliken atomic charge, and molecular electrostatic potential (MESP) map are correlated. In addition, FBTC exhibited exceptional physiological temperature sensing behaviour from 20°C -65°C with high relative sensitivity and firm stability. Hence these results confirm that FBTC is a potential candidate for photonic devices and it's also applicable in optical temperature sensing.

All-polarization-maintaining dual-comb fiber laser with mechanically shared cavity configuration and micro-optic component

An all-polarization-maintaining dual-comb fiber laser with a mechanical shared-cavity configuration was demonstrated. The laser cavity configuration was simplified and downsized using the micro-optic component of a saturable absorber mirror and a wavelength-division multiplexer. A high relative frequency stability was achieved with an Allan deviation of 0.02 Hz. Further, the all-polarization-maintained fiber-based configuration facilitated an integrated phase noise of the relative beat note between dual-frequency combs of 378 rad (10 Hz−1 kHz) and 9.0 rad (100 Hz−1 MHz). The simple, compact, and robust dual-comb fiber laser yielded highly mutually coherent dual-optical frequency combs without active servo control, and significantly simplified dual-comb spectroscopy.

EVALUATION OF THE ADAPTIVE POTENTIAL OF PROMISING SHALLOT ACCESSIONS

Ecological stability and high adaptive potential are the main factors for stable performance and yield of agricultural crops under changing environmental conditions; therefore the selection of stress-resistant genotypes is relevant at all stages of breeding. Purpose. To evaluate and select promising breeding accession of shallots by adaptive potential for the "green leaf yield" trait and its components. Methods. Field, laboratory, computational and analytical methods were used in the study. The study was conducted in outdoors at the Institute of Vegetable and Melon Growing of NAAS in 2017–2020. Five breeding hybrid accessions were investigated. Lira was the check variety. Results. Having assessed the adaptive potentials of 5 breeding accessions of shallot, we selected a promising environmentally stable accession, D-57, which was noticeable for a high yield of green leaves (5.6 kg/m2) in combination with the highest general adaptive capacity (GAC = 1.3), high stability (bi = 0.4) and genomic breeding value (GBV = 2.7) for this trait. As to the adaptive potential for the "plant height" trait, the D-57 accessions also stood out; it was characterized by high general adaptive capacity (GAC = 1.3), relative stability (Sgi = 10.9 %) and genomic breeding value (GBV = 23.4). This accession was also the best in terms of the "plant weight": trait with the genomic breeding value (GBV = 42.4), it had the largest plant weight including a bulb (75.4 g), combined high general (GAC = 17.3) and specific adaptive capacity (SAC= 129.3) with high plasticity (bi = 2.6). Conclusions. The comprehensive study of the adaptive potential of 5 promising forms of shallots distinguished the D-57 accession, which was superior to the check variety, Lira, in terms of green leaf yield, plant height and weight (including a bulb) and had a high adaptive potential and genomic breeding value for these traits.

Investigation of the potential solar cell application of Cs2AgBiBr6 lead-free double perovskite

Methylammonium lead halides are outstanding photoactive perovskites for energy conversion devices. Irrespective of excellent performance, chemical instability, and toxicity remain challenges for their potential acceptance. Recently, owing to the nontoxicity and high relative stability of Cs2AgBiX6 (X = Cl or Br), double perovskites have found as a significant substitution to the lead-based absorber for perovskite solar cells (PSCs). Especially, Cs2AgBiBr6 has appeared to be an alternative to perovskite based on lead. The unique features of Cs2AgBiBr6 like nontoxicity, higher stability, multifunctionality, and optoelectronic properties lead to promising lead-free double perovskite. In this study, the potential solar cell application of lead-free Cs2AgBiBr6 double perovskite absorber is studied through density functional theory and via experimental and theoretical analysis. SACPS-1D simulation is used to design a PSC of FTO/SnO2/Cs2AgBiBr6/Cu2O/Au cell configuration to study the effect of various parameters. The device simulation is initially optimized and validated under the experimental counterpart and then the other parameters for the material such as the absorber thickness, defect density, operating temperature, series resistance, bandgap, etc are improved to deliver a better performance. Further, the suggested device simulation is performed with various electron transport layers (ETLs) of SnO2, TiO2, and ZnO revealing these ETLs may be adopted for PSCs composed of lead-free Cs2AgBiBr6 absorber. Final optimized Cs2AgBiBr6 has a power conversion efficiency of 16.63%, 16.85%, and 16.79%, open-circuit voltages of 1.511, 1.508, and 1.510 V, current densities of 15.76, 15.71 and 15.75 mA/cm2, and fill factors of 69.84, 71.1 and 72.52 with ETLs of SnO2, TiO2, and ZnO, respectively.

Carbon bowl-confined subnanometric palladium-gold clusters for formic acid dehydrogenation and hexavalent chromium reduction

Formic acid (FA), a high-value product of CO2 hydrogenation and biomass conversion, is considered a promising liquid organic hydrogen carrier for its high hydrogen content, easy accessibility, and relative stability. The development of an efficient heterogeneous catalyst toward FA dehydrogenation and Cr(VI) reduction by FA is needed to boost its sluggish kinetics but still remains a challenge. Herein, uniformly dispersed subnanometric PdAu alloy clusters (i.e., 0.9 nm) were successfully prepared and confined by amine-functionalized carbon bowls (ACB). By virtue of the tiny size and abundant active sites of PdAu clusters, the promotional effect of surface amine groups, and electronic interaction between subnanometric PdAu clusters and support, this as-prepared PdAu/ACB catalyst exhibits superior catalytic property for additive-free FA dehydrogenation (turnover frequency, 10597 h−1 at 323 K) and Cr(VI) reduction (rate constant, 0.47 min−1 at 298 K) under mild conditions, higher than most of the catalysts reported so far. This study offers insight into the design of efficient and durable catalysts for various catalytic applications in energy and environment.

Dual-comb fiber laser for stable frequency distribution.

A passive dual-comb laser can generate two optical frequency combs with different repetition frequencies. These repetition differences have high relative stability and mutual coherence through passive common-mode noise suppression without complex tight phase locking from a single-laser cavity. The comb-based frequency distribution requires the dual-comb laser to have a high repetition frequency difference. This paper presents a high repetition frequency difference bidirectional dual-comb fiber laser based on an all-polarization-maintaining cavity configuration and a semiconductor saturable absorption mirror with single polarization output. The proposed comb laser has a standard deviation of 69 Hz and an Allan deviation of 1.17 × 10-7 at τ = 1 s under different repetition frequencies of 12.815 MHz. Moreover, a transmission experiment has been conducted. Owing to the passive common-mode noise rejection capability of dual-comb laser, after passing an 84 km fiber link, the frequency stability of the repetition frequency difference signal is improved by two orders of magnitude than the repetition frequency signal at the receiver side.

First-principles study on photoelectric properties of all-inorganic two-dimensional double perovskite Cs3AgBiBr7.

Two-dimensional (2D) all-inorganic double perovskite materials have attracted great interest owing to their unique photoelectric characteristics, such as high quantum efficiency and relative stability. However, few studies have been conducted on the 2D all-inorganic double perovskite Cs3AgBiBr7, and its photoelectric properties are unclear. In this study, we present a detailed investigation of the band structure, optical absorption spectrum, carrier mobility and exciton binding energy of the double perovskite Cs3AgBiBr7 based on the first-principles. The results show that this system has an indirect band gap and low carrier mobility, high exciton binding energy (2041.38 meV) and significant light absorption in the UV region. We also find that the material may be a potential exciton insulation candidate owing to the exciton binding energy beyond the band gap. Our calculated results also show that low dimensional perovskite Cs3AgBiBr7 is more suitable for luminescence than a photovoltaic device. We hope our theoretical results will inspire and promote the experimental exploration of 2D all-inorganic double perovskite materials for photoelectric applications.

Recent Applications of Titanium Dioxide Nanoparticles as Cancer Theranostic Agents

In medicine, the application of nanotechnology is related to the use of nanoscale materials to improve and develop new diagnostic and therapeutic methods. Due to the unique physicochemical and optical characteristics of titanium dioxide nanoparticles (TiO2 NPs), such as high biocompatibility, surface properties, and relative stability, they have been widely investigated for medical purposes, particularly as a theranostic agent in cancer diagnosis and treatment. This review concentrates on current progress in the applications of TiO2 nanostructures in cancer diagnosis and treatment domains. Studies have shown that TiO2 NPs can be promising in various medical imaging techniques. In the field of cancer treatment, researchers have evaluated the ability of TiO2 NPs in up-to-date therapeutic approaches, including drug delivery, sonodynamic, photodynamic, photothermal, and ionizing radiation therapies. In the current review, we focus on the ability of TiO2 NPS as a radiation sensitizer to improve the efficiency of cancer diagnosis and treatment. Finally, according to the studies that have been conducted on controlling and optimizing the factors involved in the TiO2 NP radiosensitization, the mechanism of TiO2 NPs in producing the radiosensitivity effect has been discussed.

Polarization-multiplexed dual-comb fiber laser based on an all-polarization-maintaining cavity configuration

In this study, we present a polarization-multiplexed, erbium-doped dual-comb fiber laser based on an all-polarization-maintaining cavity configuration. We observed that the dual-comb fiber laser easily realized the self-starting mode-locking operation due to the non-linear amplifying loop mirror (NALM) with a non-reciprocal phase shifter. Furthermore, owing to the sharing of the NALM part, the two outputs from this laser configuration had similar center wavelengths, with small different repetition rates (∆frep). In the free-running operation, the standard deviation of relative stability for Δfrep of 2.09 kHz was measured to be 1.59 Hz, and the full width at half-maximum of the relative beat note between the two frequency combs in the optical frequency domain was approximately 1 kHz. These results show that the two frequency combs from this laser configuration have high relative stability and mutual coherence.

The Challenge to Link Biology, Chemistry, and Physics: Results of a Longitudinal Study on Self-Rated Content Knowledge

Interdisciplinary science teaching in (lower) secondary education can lead to out-of-field teaching in countries with a discipline-specific teacher education. For example, the discipline-specific teacher education in Germany does not fit the current demands of interdisciplinary science teaching, especially in comprehensive schools. Self-rated content knowledge (srCK)—a specific part of academic self-concept—of (prospective) teachers is important in the context of motivational orientations and due to the reciprocal relation of academic self-concept and performance. Previous research did not focus on the long-term development of core idea-based srCK regarding secondary education. Thus, we surveyed 271 (prospective) teachers of biology, chemistry, and physics three times (2019–2021). In addition, we surveyed seven chemistry and physics pre-service teachers participating in a biology content knowledge (CK) course. Taking into account measurement invariance, we used structural equation modeling and latent change models. The srCK of biology, chemistry, and physics showed a high relative and absolute stability. We did not find any correlation between srCK of biology and chemistry. SrCK of chemistry and physics always showed a small positive correlation. SrCK of biology and physics always had a strong negative correlation. Supporting these results, studying physics had a negative effect on the srCK of biology, and studying chemistry had a positive effect on the srCK of physics. Additionally, studying the subject of the srCK in question always had a strong positive effect. Though srCK seems to be time-stable, a biology CK course for pre-service chemistry and physics teachers showed strong positive changes in their srCK of biology. Thus, training in an unstudied subject could help to cope with the undesired time-stability of srCK. In addition, the strong negative correlation between the srCK of biology and of physics needs to be addressed in teacher education.

PTCL1-EstA from Paenarthrobacter aurescens TC1, a Candidate for Industrial Application Belonging to the VIII Esterase Family

The esterase PTCL1-EstA from Paenarthrobacter aurescens TC1 was expressed in Escherichia coli and characterized. An 1152 bp open reading frame encoding a 383 amino acid polypeptide was successfully expressed, the C-terminally His6-tagged PTCL1-EstA enzyme was purified, and the predicted molecular mass of the purified PTCL1-EstA was 40.6 kDa. The EstA family serine hydrolase PTCL1-EstA belongs to the esterase family VIII, contains esterase-labeled S-C-S-K sequences, and homologous class C beta-lactamase sequences. PTCL1-EstA favored p-nitrophenyl esters with C2-C6 chain lengths, but it was also able to hydrolyze long-chain p-nitrophenyl esters. Homology modelling and substrate docking predicted that Ser59 was an active site residue in PTCL1-EstA, as well as Tyr148, Ala325, and Asp323, which are critical in catalyzing the enzymatic reaction of p-nitrophenyl esters. PTCL1-EstA reached the highest specific activity against p-nitrophenyl butyrate (C4) at pH 7.0 and 45 °C but revealed better thermal stability at 40 °C and maintained high relative enzymatic activity and stability at pH 5.0–9.0. Fermentation medium optimization for PTCL1-EstA increased the enzyme activity to 510.76 U/mL, tapping the potential of PTCL1-EstA for industrial production.

Mechanical sharing dual-comb fiber laser based on an all-polarization-maintaining cavity configuration.

We present a mechanical sharing, dual-comb fiber laser based on an all-polarization-maintaining cavity configuration and a nonlinear amplifying loop mirror mode-locking mechanism. This simple setup yields dual-optical frequency combs with a high level of mutual coherence without active servo control. We realized a high relative stability with a standard deviation of 0.27 Hz and a relative beat note between the dual-frequency combs with a full-width at half-maximum of ∼50Hz. Dual-frequency combs were found to have high relative stability and mutual coherence owing to passive common-mode noise suppression using a mechanical sharing laser cavity. This laser configuration can significantly simplify dual-comb spectroscopy.