Density Of Nuclei Research Articles

A novel bistable device to study mechanosensitive cell responses to instantaneous stretch

The behavior of cells and tissues in vivo is determined by the integration of multiple biochemical and mechanical signals. Of the mechanical signals, stretch has been studied for decades and shown to contribute to pathophysiological processes. Several different stretch devices have been developed for in vitro investigations of cell stretch.In this work, we describe a new 3D-printed uniaxial stretching device for studying cell response to rapid deformation. The device is a bistable compliant mechanism holding two equilibrium states—an unstretched and stretched configuration—without the need of an external actuator. Furthermore, it allows multiple simultaneous measurements of different levels of stretch on a single substrate and is compatible with standard immunofluorescence imaging of fixed cells as well as live-cell imaging.To demonstrate the effectiveness of the device to stretch cells, a test case using aligned myotubes is presented. Leveraging material area changes associated with deformation of the substrate, changes in nuclei density provided evidence of affine deformation between cells and substrate. Furthermore, intranuclear deformations were also assessed and shown to deform non-affinely.As a proof-of-principle of the use of the device for mechanobiological studies, we uniaxially stretched aligned healthy and dystrophic myotubes that displayed different passive mechanical responses, consistent with previous literature in the field. We also identified a new feature in the mechanoresponse of dystrophic myotubes, which is of potential interest for identifying the diseased cells based on a quick mechanical readout. While some applications of the device for elucidating passive mechanical responses are demonstrated, the simplicity of the device allows it to be potentially used for other modes of deformation with little modifications.

SOFIA FEEDBACK Survey: PDR Diagnostics of Stellar Feedback in Different Regions of RCW 49

We quantified the effects of stellar feedback in RCW 49 by determining the physical conditions in different regions using the [C ii] 158 μm and [O i] 63 μm observations from SOFIA, the 12CO (3–2) observations from APEX, and the H2 line observations from Spitzer telescopes. Large maps of RCW 49 were observed with the SOFIA and APEX telescopes, while the Spitzer observations were only available toward three small areas. From our qualitative analysis, we found that the H2 0–0 S(2) emission line probes denser gas compared to the H2 0–0 S(1) line. In four regions (“northern cloud,” “pillar,” “ridge,” and “shell”), we compared our observations with the updated PDR Toolbox models and derived the integrated far-ultraviolet flux between 6 and 13.6 eV (G 0), H nucleus density (n), temperatures, and pressures. We found the ridge to have the highest G 0 (2.4 × 103 Habing units), while the northern cloud has the lowest G 0 (5 × 102 Habing units). This is a direct consequence of the location of these regions with respect to the Wd2 cluster. The ridge also has a high density (6.4 × 103 cm−3), which is consistent with its ongoing star formation. Among the Spitzer positions, we found the one closest to the Wd2 cluster to be the densest, suggesting an early phase of star formation. Furthermore, the Spitzer position that overlaps with the shell was found to have the highest G 0, and we expect this to be a result of its proximity to an O9V star.

Thermal behavior of Li electrode in all-solid-state batteries and improved performance by temperature modulation

All-solid-state lithium metal batteries (ASSLMBs) hold tremendous promise in electric vehicles and portable electronic devices owing to the remarkably improved safety and energy density. However, the uncontrollable Li dendrites seriously hinder the cycling performance of ASSLMBs, and the fickle environment urgently requires a reliable energy supply over a wide temperature range. Understanding the temperature-dependent behavior of Li metal electrode holds great significance for breaking the bottleneck. Herein, we experimentally and theoretically investigate the temperature-dependent morphological evolution of electrodeposited Li in solid electrolyte from -20 °C to 90 °C. It is found that as temperature increases, nuclei size, nuclei density, structural compactness and growth direction of electrodeposited Li are significantly altered. The thermal effect on Li nucleation and growth is further revealed by molecular dynamics simulations. Based on this, we propose a temperature modulation strategy to improve the cyclability of Li metal electrode. By charging at the optimal temperature, the cycling life and Coulomb efficiency of Li electrode can be simultaneously improved. Our investigation gives valuable insights towards temperature-dependent Li deposition in solid electrolyte and will provide rational guidance for the thermal management of ASSLMBs operated in extreme environments.

Ultrathin ZIF‐8 Membrane through Inhibited Ostwald Ripening for High‐Flux C3H6/C3H8 Separation

AbstractMetal–organic frameworks (MOFs) are one of the most promising membrane materials for olefin/paraffin separations. However, most of MOF membranes have a thickness over 1 µm, which greatly compromises the permeation flux. While previous studies are focused on increasing crystal nucleus density on the substrates, achieving ultrathin membrane via modulation of the crystal growth is lacking. Herein, an inhibited Ostwald ripening (IOR) strategy is proposed to fabricate ultrathin ZIF‐8 membranes, through incorporating polymer‐based inhibitors into the membrane formula to inhibit the growth process of ZIF‐8 crystals via the metal–organic coordination. The IOR process can be readily tuned by varying the functional groups, molecular weights, and concentrations of the inhibitors, enabling a facile control over the IOR degree and thus the membrane thickness. Consequently, the thickness of ZIF‐8 membranes can be dramatically reduced to 180 nm. The resulting membranes exhibit ultrahigh C3H6/C3H8 separation performance with C3H6 permeance of 386 GPU and C3H6/C3H8 separation factor of 120. It is anticipated that this straightforward and efficient IOR strategy can open a new avenue for the fabrication of ultrathin MOF membranes to tackle many critical molecular separations.

Mechanism and kinetics of Gold Nanoparticles Electrodeposited from Au (III) Ions Dissolved in a Deep Eutectic Solvent and Its Analytical Performance Towards Dopamine Quantification

The mechanism and kinetics of the electrochemical nucleation and growth of gold nanoparticles, AuNPs, onto a glassy carbon electrode, GCE, from Au(III) dissolved in the reline deep eutectic solvent, DES, at 70 °C, were assessed, for the first time. From the potentiodynamic technique it was found that gold electrodeposition onto the GCE substrate (Au(III)DES + 3e− (GCE) = Au(s)/GCE) is a diffusion-controlled process that requires of an overpotential nucleation to occur. The potentiostatic current density transients, recorded at different applied overpotentials, during the electrodeposition of AuNPs were described by a mechanism where multiple nucleation of 3D gold centers with mass-transfer controlled growth, occurs simultaneously with Au(III) adsorption (at the early stages) and the DES residual water reduction on the growing surfaces of the Au nuclei. From this analysis the diffusion coefficient of Au(III) ions was estimated as (2.56 ± 0.12) × 10−9 cm s−1 and it was found that the number density of Au nuclei, N s, depends exponentially on the applied overpotential while the nucleation frequency, A, was practically constant and the water reduction contribution increases linearly. From SEM images and EDX spectrum of the GCE surface, electrodeposited with gold (GCE/AuNPs), it was found that the Au deposit was formed by aggregates, (183 ± 37) nm average size, of AuNPs (of ca 50 nm diameter) and a density of (1.8 ± 0.3) × 109 aggregates cm−2. The GCE/AuNPs was used for the Dopamine, DA, electrochemical quantification in the presence of uric acid, UA, with the following analytical performance: sensitivity of (32.49 ± 0.37) μA mM−1 and (28.6 ± 0.2) μM detection limit.

Influence of 1,8-naphthalimide derivatives as additives on the electrodeposition of tin from methanesulfonic acid system

A series of 1,8-naphthalimide derivatives containing different quaternary ammonium groups have been synthesized by a two-step method. Electrochemical tests and quantum chemical calculations demonstrated that 1,8-naphthalimide parent conjugate ring adsorbed to the tin surface and occupied active sites, and positive charges on aromatic ring quaternary ammonium group competed with Sn2+ for electrons. Moreover, higher positive charge density and larger conjugate area of the aromatic ring quaternary ammonium group were considered to increase cathodic polarization to inhibit the deposition rate of tin ions and hydrogen evolution. The substituted naphthalimide NI4 which had a current density suppression effect of 90% and negatively shifted tin deposition and hydrogen evolution potential by 20 mV and 0.45 V respectively was deemed to be the best performed one on this basis. In actual tin plating, compared with base electrolyte, the tin layer surface under NI4 electrolyte was smoother at any current density and had no leakage or agglomeration. SEM showed a higher nuclei density with smaller feature size, and XRD demonstrated a shift in the dominant crystalline plane from (420) to (200).

Особенности строения хрусталика при набухающей катаракте

Purpose. To study the structure of the swelling lens, the dependence of its anatomical parameters on the nucleus sizes and density, patients' age. Material and methods. 64 patients with intumescent mature cataract were examined. All patients underwent phacoemulsification with a two-stage continuous circular capsulorhexis. After the 2–2.5 mm capsulorhexis had been created, the liquid lenticular masses were removed from the anterior and posterior lens compartment with the aspiration/irrigation system. Visually we determined the size of the nucleus, its color and density according to Buratto's classification. Results. When performing this work four types of the swelling lens structure were detected. Type I – a small emerging white nucleus with large amount of liquid lenticular masses in the anterior and posterior lens compartment, II degree of density according to Buratto's classification. The mean age was 49.12 ± 3.11 years old. The related ophthalmic diseases accounted for 36.4 %. Type II – a large white nucleus with the presence of liquefied lenticular masses in the anterior and posterior lens compartment. III degree of density according to Buratto's classification. The mean age was 71.15 ± 5.07 years old. Associated diseases – 65 %. Type III – a large brown nucleus with the presence of liquefied lenticular masses in the anterior and posterior lens compartment. IV degree of density according to Buratto's classification. The mean age was 75.87 ± 1.48 years old. Associated diseases – 79 %. Type IV – a small, very dense, brown nucleus with liquid lenticular masses. V degree of density according to Buratto's classification. The mean age was 77.34 0 ±2.47 years old. Associated diseases – 100 %. Conclusion. Four types of lens structure in intumescent cataract were described depending on the nucleus size, density, the amount of the lenticular masses. By means of UBM it was shown that intumescent cataract was accompanied by the alterations of the ocular anterior segment parameters, which depended on the type of lens structure. It was revealed that the types of swelling lens structure were directly connected to the patients' age: mean age of patients with type I – 49.12 ± 3.11 years old, with type II – 71.15 ± 5.07, with type III – 75.87 ± 1.48, with type IV – 77.34 ± 2.47 years old. Keywords: ophthalmology, intumescent cataract, types of lens structure.

Bubble nuclei: Single-particle versus Coulomb interaction effects

The detailed investigation of microscopic mechanisms leading to the formation of bubble structures in nuclei is performed in the framework of covariant density functional theory. The main emphasis of this study is on the role of single-particle degrees of freedom and Coulomb interaction. In general, the formation of bubbles lowers the Coulomb energy. However, in nuclei this trend is counteracted by the quantum nature of the single-particle states: only specific single-particle states with specific density profiles can be occupied with increasing proton and neutron numbers. A significant role of the central classically forbidden region at the bottom of the wine bottle potentials in the formation of nuclear bubbles (via primarily the reduction of the densities of the $s$ states at $r=0$) is revealed for the first time. Their formation also depends on the availability of low-$l$ single-particle states for occupation since single-particle densities represent the basic building blocks of total densities. Nucleonic potentials disfavor the occupation of such states in hyperheavy nuclei and this contributes to the formation of bubbles in such nuclei. Existing bubble indicators are strongly affected by single-particle properties and thus they cannot be reliable measures of bulk properties (such as the Coulomb interaction). An additivity rule for densities is proposed for the first time. It was shown that the differences in the densities of bubble and flat density nuclei follow this rule in the $A\ensuremath{\approx}40$ mass region and in superheavy nuclei with comparable accuracy. This strongly suggests the same mechanism of the formation of central depression in bubble nuclei of these two mass regions. Nuclear saturation mechanisms and self-consistency effects also affect the formation of bubble structures. The detailed analysis of different aspects of bubble physics strongly suggests that the formation of bubble structures in superheavy nuclei is dominated by single-particle effects. The role of the Coulomb interaction increases in hyperheavy nuclei but even for such systems we do not find strong arguments that the formation of bubble structures is dominated by it.

Unified neutron star EOSs and neutron star structures in RMF models

In the framework of the Thomas-Fermi approximation, we systematically study the EOSs and microscopic structures of neutron star matter in a vast density range with n b ≈ 10−10-2 fm−3, where various covariant density functionals are adopted, i.e., those with nonlinear self couplings (NL3, PK1, TM1, GM1, MTVTC) and density-dependent couplings (DD-LZ1, DDME-X, PKDD, DD-ME2, DD2, TW99). It is found that the EOSs generally coincide with each other at n b ≲ 10−4 fm−3 and 0.1 fm−3 ≲ n b ≲ 0.3 fm−3, while in other density regions they are sensitive to the effective interactions between nucleons. By adopting functionals with a larger slope of symmetry energy L, the curvature parameter K sym and neutron drip density generally increases, while the droplet size, proton number of nucleus, core-crust transition density, and onset density of non-spherical nuclei, decrease. All functionals predict neutron stars with maximum masses exceeding the two-solar-mass limit, while those of DD2, DD-LZ1, DD-ME2, and DDME-X predict optimum neutron star radii according to the observational constraints. Nevertheless, the corresponding skewness coefficients J are much larger than expected, while only the functionals MTVTC and TW99 meet the start-of-art constraints on J. More accurate measurements on the radius of PSR J0740 + 6620 and the maximum mass of neutron stars are thus essential to identify the functional that satisfies all constraints from nuclear physics and astrophysical observations. Approximate linear correlations between neutron stars’ radii at M = 1.4M ⊙ and 2M ⊙, the slope L and curvature parameter K sym of symmetry energy are observed as well, which are mainly attributed to the curvature-slope correlations in the functionals adopted here. The results presented here are applicable for investigations of the structures and evolutions of compact stars in a unified manner.

Crystal quality improvement of ZnTe (1 1 0) thin film prepared on sapphire by increasing nuclei density on substrate surface

ZnTe thin films were prepared on r, S-plane nanofacet substrates to achieve a high-crystal-quality layer with a (110) orientation. Scanning electron microscopy was used to study the nucleation process. Selective formation of growth nuclei can be achieved by controlling the substrate temperature. The low-temperature grown amorphous layers changed to nuclei by annealing. The surface amorphous layer was completely removed when the annealing temperature was too high. Zn beam irradiation during the annealing removed materials selectively from the r-nanofacet. Migration-enhanced epitaxy (MEE) was introduced to enlarge the nuclei size, and a thick-layer growth by conventional molecular beam epitaxy (MBE) followed. The MEE sequence was increased up to 1200 cycles, and the substrate temperature for MEE and MBE was set to higher temperatures than the conventional MBE substrate temperature (the conventional substrate temperature was around 340 °C). The crystal quality of the thin film was analyzed using the X-ray pole figure, θ–2θ measurements and photoluminescence. (110) oriented layer formation perpendicular to the substrate surface was confirmed after introducing those techniques. The low-temperature photoluminescence measurement indicated the high quality of the thick layer.

Attention to region: Region-based integration-and-recalibration networks for nuclear cataract classification using AS-OCT images.

Nuclear cataract (NC) is a leading eye disease for blindness and vision impairment globally. Accurate and objective NC grading/classification is essential for clinically early intervention and cataract surgery planning. Anterior segment optical coherence tomography (AS-OCT) images are capable of capturing the nucleus region clearly and measuring the opacity of NC quantitatively. Recently, clinical research has suggested that the opacity correlation and repeatability between NC severity levels and the average nucleus density on AS-OCT images is high with the interclass and intraclass analysis. Moreover, clinical research has suggested that opacity distribution is uneven on the nucleus region, indicating that the opacities from different nucleus regions may play different roles in NC diagnosis. Motivated by the clinical priors, this paper proposes a simple yet effective region-based integration-and-recalibration attention (RIR), which integrates multiple feature map region representations and recalibrates the weights of each region via softmax attention adaptively. This region recalibration strategy enables the network to focus on high contribution region representations and suppress less useful ones. We combine the RIR block with the residual block to form a Residual-RIR module, and then a sequence of Residual-RIR modules are stacked to a deep network named region-based integration-and-recalibration network (RIR-Net), to predict NC severity levels automatically. The experiments on a clinical AS-OCT image dataset and two OCT datasets demonstrate that our method outperforms strong baselines and previous state-of-the-art methods. Furthermore, attention weight visualization analysis and ablation studies verify the capability of our RIR-Net for adjusting the relative importance of different regions in feature maps dynamically, agreeing with the clinical research.

Eikonal Approximation for K+–Nucleus Elastic Scattering

The elastic scattering of kaons from different targets 6Li, 12C, and 40Ca at energies 635, 715, and 800 MeV have been studied. The equivalent local potential form of Kisslinger optical potential with the eikonal approximation using Wallace expansion up to the 2nd order have been used. The potential depends on the density of the target nuclei, and the scattering amplitude parameters. Satisfactory fits to the elastic scattering experimental data are obtained.

Correlation between nuclear temperature and symmetry energy in subsaturation nuclear matter density

Herein, a study of the correlation between nuclear temperature and symmetry energy is presented for heavy ion collisions at intermediate energies via the isospin-dependent quantum molecular-dynamics model. It is found that different symmetry energy parameters change the density and kinetic energy distribution of the hot nuclei. More importantly, nuclear temperatures that are based on kinetic energy properties can be used to study symmetry energy information.

Modelling Nucleation during Electrodeposition By MODEL Method. Parametric Identification Considering Agitation By Rde or Ultrasound

Nowadays, 40% of the world wide used energy is provided by electric power and this share should reach about 60% by 2040. For environmental reasons, it is crucial to ensure low dissipation loss in power electronic devices by optimizing energy conversion. In the field of renewable energies and automotive electronics, possible energy savings are estimated to be between 20 and 35%. For that purpose, innovative power components and modules are required, with a growing interest for fast and simple joining processes in their fabrication management, in the case for example of the assembly of large-size double-side cooled modules. Several options are possible, including free sintering of metallic pastes or electroforming welding. In all cases, this requires a great control of both surfaces to be joined, mostly prepared by electrodeposition (microstructure, porosity, alloy composition). But the final properties of electrodeposited coatings are strongly dependent of the first nucleation steps, which influence the whole layer structure. In this frame, the modelling of a nucleation process followed by diffusion limited three dimensional growth is an area of promising interest. The study of potentiostatic current transients is a relevant methodology, allowing the determination of several parameters such as nucleation rate, nucleus density, and number of active sites. Different competing models are available, such as Scharifker and Hills [1] and Scharifker and Mostany [2]. By using the model method i.e. the identification of the model parameters by error minimization, it is possible to reach an accurate description of the first layer growth in the case of different metals such as silver and copper. Nevertheless, little attention have been paid to changes in hydrodynamic conditions, for example in the study of current response under forced convection [3]. The present work describes the extension of the model method to the modelling of the first steps of nucleation growth in the case of a sample exposed to an ultrasonic irradiation, which was compared to forced convection induced by a rotating disc electrode at the very same agitation level (equivalent velocity [4,5]. Eventually, the case of electrodeposited alloys was examined, as a function of their Brenner classifications (anomalous and normal codeposition [6]). The limitation of the data processing by the numerical approach are also discussed.[1] Scharifker, B. & Hills, G. Theoretical and experimental studies of multiple nucleation. Electrochimica Acta 28, 879–889 (1983).[2] Scharifker, B. R. & Mostany, J. Three-dimensional nucleation with diffusion controlled growth. J. Electroanal. Chem. Interfacial Electrochem. 177, 13–23 (1984).[3] Hyde, M. E. & Compton, R. G. Theoretical and experimental aspects of electrodeposition under hydrodynamic conditions. J. Electroanal. Chem. 581, 224–230 (2005).[4] Pollet B.G., Hihn J.-Y., Doche M.L, Mandroyan A., Lorimer J.P., Mason T.J “Transport limited currents close to an ultrasonic horn: equivalent flow velocity determination”, Journal of Electrochemistry Society, 154(10), E131-E138, (2007)[5] A. Nevers, L. Hallez, F. Touyeras, J.-Y. Hihn, Effect of ultrasound on silver electrodeposition: Crystalline structure modification, Ultrason. Sonochem. 40 (2018)[6] Brenner, A. Electrodeposition of alloys. Principles and practice Volume II, (1963).

On the Prediction of Macrosegregation in Vacuum Arc Remelted Ingots

The chemical homogeneity and metallurgical structure of vacuum arc remelted (VAR) zirconium ingots are directly responsible for product quality. It is therefore important to understand the relationship between these properties and the operating conditions. An in-depth analysis of the modelling of solidification phenomena during the VAR was carried out. Such model, solves a coupled set of transient equations for heat, momentum, solute transport and turbulence in an axisymmetric geometry. The remelting and cooling of a cylindrical ingot are calculated for time-dependent operating parameters. The solidification mechanisms implemented in the model can be applied to multi-component industrial alloys such as Zircaloy-4, which provides information on the macrosegregation phenomena studied in this paper. The model results were validated, based on the remelting of a specially designed chemically homogeneous Zircaloy-4 electrode. The results illustrate the importance of thermal and solute convection, the importance of the permeability of the partially solid material and the weak influence of nuclei density and solute diffusion in the solid phase on the prediction of macrosegregation in Zircaloy-4 ingots.

Ferroelectric Domain Reversal Dynamics in LiNbO3 Optical Superlattice Investigated with a Real-Time Monitoring System.

The optical superlattice structure derived from a periodic poling process endows ferroelectric crystals with tunable optical property regulation, which has become one of the most efficient strategies for fabricating high-efficiency optical devices. Achieving a precise superlattice structure has been the main barrier for preparation of specific optical applications due to the unclear dynamics of domain structure regulation. Herein, a real-time monitoring system for the in situ observation of periodic poling of lithium niobate is established to investigate ferroelectric domain reversal dynamics. The formation of reversed domain nuclei, growth, and expansion of the domain are monitored, which is highly related to domain growth dynamics. The nucleation and growth of domain are discussed combined with the monition of domain reversal and the variation of local electric field distribution along with finite element analysis. An electrode configuration with multiholes is proposed to use the local electric field more efficiently and controllably, which could achieve a higher domain nucleus density with high uniformity. Two-mm-thick periodically poled LiNbO3 crystals with high quality are achieved. A nonlinear light conversion from 1064.2 to 3402.4nm is realized by the single-resonance optical parameter oscillator with a nonlinear optical efficiency up to 26.2%.

S -wave pion condensation in symmetric nuclear matter

S-wave pion-nucleon interactions in the linear sigma model, and in Manohar-Georgi and Gasser-Sainio-Svarc models with finite number of terms in Lagrangians, as well as in a general phenomenological approach are reviewed. Subtleties associated with the current algebra theorems and field redefinitions are discussed. In the first and third models most likely the s-wave pion condensation in the isospin-symmetric matter does not occur at least up to high densities, whereas within the second model it may appear already at moderate densities. In the phenomenological approach two parameterizations of the s-wave pion-nucleon scattering amplitude and the pion polarization operator used in the literature are considered. The first parameterization employs the off-mass-shell amplitude and allows to fulfil the current algebra theorems. Using it the s-wave pion polarization operator in the isospin-symmetric matter is reconstructed within the gas approximation. With this pion polarization operator the s-wave pion condensation in the isospin-symmetric matter does not occur at least up to high densities. Second parameterization uses the on-mass-shell pion-nucleon scattering amplitude and does not satisfy the Adler and Weinberg conditions. With such a parameterization most likely the s-wave pion condensation in the isospin-symmetric matter may occur already at the nucleon density $n\simeq (1.4-2.5) n_0$, where $n_0$ is the density of the atomic nucleus, that should result in observable effects. Both parameterizations allow to successfully describe the pion atom data.

Constraints on the symmetry energy from PREX-II in the multimessenger era

The neutron skin thickness $\Delta r_{\rm{np}}$ of heavy nuclei is essentially determined by the symmetry energy density slope $L({\rho })$ at $\rho_c = 0.11~{\rm {fm}^{-3}}\approx 2/3\rho_0$ ($\rho_0$ is nuclear saturation density), roughly corresponding to the average density of finite nuclei. The PREX collaboration recently reported a model-independent extraction of $\Delta r^{208}_{\rm{np}} = 0.283 \pm 0.071$ fm for the $\Delta r_{\rm{np}}$ of $^{208}$Pb, suggesting a rather stiff symmetry energy $E_{\rm{sym}}({\rho })$ with $L({\rho_c }) \ge 52$ MeV. We show that the $E_{\rm{sym}}({\rho })$ cannot be too stiff and $L({\rho_c }) \le 73$ MeV is necessary to be compatible with (1) the ground-state properties and giant monopole resonances of finite nuclei, (2) the constraints on the equation of state of symmetric nuclear matter at suprasaturation densities from flow data in heavy-ion collisions, (3) the largest neutron star (NS) mass reported so far for PSR J0740+6620, (4) the NS tidal deformability extracted from gravitational wave signal GW170817 and (5) the mass-radius of PSR J0030+045 measured simultaneously by NICER. This allows us to obtain $52 \le L({\rho_c }) \le 73$ MeV and $0.212 \le \Delta r^{208}_{\rm{np}} \le 0.271$ fm, and further $E_{\rm{sym}}({\rho_0 }) = 34.3 \pm 1.7$ MeV, $L({\rho_0 }) = 83.1 \pm 24.7$ MeV, and $E_{\rm{sym}}({2\rho_0 }) = 62.8 \pm 15.9$ MeV. A number of critical implications on nuclear physics and astrophysics are discussed.

Simulation of Diffusion-Controlled Growth of Interdependent Nuclei under Potentiostatic Conditions.

The problem of diffusion-controlled growth following an instantaneous nucleation event was studied within the framework of a new numerical model, considering the spatial distribution of hemispherical nuclei on the electrode surface and the mutual influence of growing nuclei via the collision of 3D diffusion fields. The simulation of the diffusion-controlled growth of hexagonal and random ensembles was performed at the overpotential-dependent number density of nuclei. The diffusion flow to each nucleus within a random ensemble was simulated by the finite difference method using the derived analytical expressions for the surface areas and the volumes formed at the intersection of 3D diffusion fields with the side faces of a virtual right prism with a Voronoi polygon base. The implementation of this approach provides an accurate calculation of concentration profiles, time dependences of the size of nuclei, and current transients. The results, including total current density transients, growth exponents, and nucleus size distribution, were compared with models developed within the concept of planar diffusion zones, the mean-field approximation and the Brownian dynamics simulation method, as well as with experimental data from the literature. The prospects of the model for studying the initial stages of electrocrystallization were discussed.

Effect of synthesized sulfonate derivatives as nucleating agents on crystallization behavior of poly(lactic acid)

ABSTRACT The improvement of the crystallization of poly(lactic acid) (PLA) is one of the key areas to allow PLA to perform better at higher temperature and load bearing. Due to its slow crystallization rate, either organic or inorganic nucleating agents (NAs) can be used to improve the crystallization rate of PLA. In the case of organic NAs, aromatic sulfonate salt and bisamide compounds are promising ones because they can control better clarity. The aim of this work was to study the crystallization behavior of PLA using as-synthesized dimethyl 5-sulfoisophthalate sodium salt (SSIPA) as a nucleating agent in comparison with the commercial sulfonate salt (LAK-301). Two grades of PLA (PLA L105 and PLA 3251D) were used in this study. PLA samples were prepared by internal mixer and compression molding. All samples were investigated by DSC and POM. The results from DSC showed that after introducing the nucleating agents into PLA, the crystallinity in all samples was improved. The highest crystallinity at 57.48% was obtained from PLA L105/SSIPA1.0. Isothermal crystallization kinetics showed the improvement in overall crystallization rate of PLA with nucleating agents. The lowest half time crystallization obtained was 1.19 min for PLA L105/SSIPA1.0 at 135 °C. The results from POM indicated the substantial increase of the nucleus density and smaller spherulite size upon adding nucleating agents.