Alignment Behavior Research Articles

The Role of Interface Band Alignment in Epitaxial SrTiO3/GaAs Heterojunctions.

Correlated oxides are known to have remarkable properties, with a range of electronic, magnetic, optoelectronic, and photonic functionalities. A key ingredient in realizing these properties into practical technology is the effective and scalable integration of oxides with conventional semiconductors. Unlocking the full spectrum of functionality requires atomically abrupt oxide-semiconductor interfaces and intimate knowledge of their potential landscape and charge transport. In this study, we investigated the electrical properties of epitaxial SrTiO3/GaAs heterostructures by examining the band alignment and transport behavior at the interface. We employ X-ray photoelectron spectroscopy (XPS) to measure the barriers for electrons and holes across the interface and, through them, explain the transport behavior for junctions with n- and p-type GaAs. We further show qualitative evidence of the strong photoresponse of these structures, illustrating the potential of these structures in optoelectronic devices. These results establish the fundamental groundwork for utilizing these interfaces toward new devices and define their design space.

Linking Local Insights to Global IR: Locating Malaysian Contours and Contributions

This article traces the trajectories, theoretical propensities, and thematic insights underlying Malaysian scholarly thinking and writings about international relations (IR). It argues that while their contributions to the Global IR research program have been indirect and implicit, they are not insignificant. The contributions are not claims of exceptionalism but expressions of diverse experiences, perspectives, and narratives that are reflective of the contesting, yet recurring logics significant for understanding and explaining small- and medium-sized states’ behavior in an anarchical world. Three themes are particularly pertinent: (1) external policy choices are extensions of internal attributes; (2) small-state outlook on regionalism and multilateralism; and (3) middle-state alignment behavior. Local insights contribute to Global IR by enriching, expanding, and exporting national narratives and regional mindsets into thematic thrusts pertinent for making sense of similar cases elsewhere, thereby pluralizing the universality and inclusivity of IR concepts and theories.

An investigation of the effect of inducing molecular alignment on the lubrication performance of 5CB liquid crystal

The lubrication alignment behaviors of 4-Cyano-4′-pentylbiphenyl (5CB) liquid crystal were investigated. A 60 s-long running-in pre-treatment was first performed using micro-sized diamonds. The ball was then deflected by a certain direction and an alignment agent (Sebacic Acid) was applied on the disc. Results show that the coefficients of friction for GCr15 and Si3N4 self-matching pairs were reduced to 0.036 and 0.017 respectively, 45.5 % and 67.3 % lower than the ones lubricated directly with 5CB. The surface morphology after running-in-deflection was smoother and flatter, with enhanced surface texture characteristics. It is believed that increased the order parameter of 5CB, induced by the synergistic effect of the alignment agent and running-in-deflection, is the reasons for the improvement in lubricating performance.

Asymptotic stability of rarefaction wave for compressible Euler system with velocity alignment

In this paper, we study the asymptotic stability of the rarefaction wave for the one-dimensional compressible Euler system with nonlocal velocity alignment. Namely, for the initial data approaching to rarefaction wave, we prove the corresponding solution converges toward the rarefaction wave. Moreover, we obtain this system has weak alignment behavior. We develop some promoted estimates for the smooth approximate rarefaction wave and new a priori estimates by Fourier analysis tools. Moreover, we introduce the weighted energy method and Besov spaces to obtain the key high-order derivative estimates, in which we overcome the difficulties caused by the nonlocal velocity alignment. It is worth mentioning that this is the first stability result of rarefaction wave for compressible Euler system with velocity alignment.

Effect of polymer concentration on molecular alignment behavior during scanning wave photopolymerization

Molecularly aligned liquid-crystalline (LC) polymer films hold great promise for next-generation high-performance photonics, electronics, robotics, and medical devices. Photoalignment methods capable of achieving precise molecular alignment in a noncontact manner have been actively studied. Recently, we proposed the concept of using spatiotemporal photopolymerization to induce molecular diffusion and the resulting alignment, termed scanning wave photopolymerization (SWaP). The spatial gradient of the polymer concentration is the dominant factor in inducing the molecular diffusion and alignment of LCs. However, the effect of polymer concentration on molecular alignment behavior remains unclear. In this study, we performed SWaP at different exposure energies to modulate the polymer concentration during polymerization. We found that a certain polymer concentration was required to initiate the alignment. Furthermore, the phase diagram of the polymer/monomer mixtures and real-time observations during SWaP revealed that phase emergence and unidirectional molecular alignment occurred simultaneously when the polymer concentration exceeded 50%. Since SWaP achieves molecular alignment coincident with photopolymerization, it has the potential to revolutionize material fabrication by consolidating the multiple-step processes required to create functional materials in a single step.

State survival vs leaders’ survival: how ethnic conflicts affect a state’s international alignment behavior?

ABSTRACT This article examines the underlying factors contributing to a more strategic and rational alignment behaviour exhibited by certain post-Soviet states compared to others in the region and beyond, despite the high stakes of domestic politics. Specifically, it focuses on Azerbaijan, Georgia, and Moldova, suggesting their consistent, state-centric foreign policies arise from facing protracted ethnic conflicts threatening their territorial integrity. The notion of differential survival risks is proposed to explain this phenomenon. Consequently, resolving these conflicts becomes the paramount concern for these states’ leadership to avoid substantial territorial losses or even loss of sovereignty, relegating domestic issues to a secondary status.

Lexical Alignment is Pervasive Across Contexts in Non-WEIRD Adult-Child Interactions.

Lexical alignment, a communication phenomenon where conversational partners adapt their word choices to become more similar, plays an important role in the development of language and social communication skills. While this has been studied extensively in the conversations of preschool-aged children and their parents in Western, Educated, Industrialized, Rich, and Democratic (WEIRD) communities, research in other pediatric populations is sparse. This study makes significant expansions on the existing literature by focusing on alignment in naturalistic conversations of school-aged children from a non-WEIRD population across multiple conversational tasks and with different types of adult partners. Typically developing children aged 5 to 8 years (n = 45) engaged in four semi-structured conversations that differed by task (problem-solving vs. play-based) and by partner (parent vs. university student), resulting in a corpus of 180 conversations. Lexical alignment scores were calculated and compared to sham conversations, representing alignment occurring at the level of chance. Both children and adults coordinated their conversational utterances by re-using or aligning each other's word choices. This alignment behavior persisted across conversational tasks and partners, although the degree of alignment was moderated by the conversational context. These findings suggest that lexical alignment is a robust phenomenon in conversations between school-age children and adults. Furthermore, this study extends lexical alignment findings to a non-WEIRD culture, suggesting that alignment may be a coordination strategy employed by adults and children across diverse linguistic and cultural backgrounds.

Synthesis and Characterization of Side-Chain Liquid-Crystalline Block Copolymers Containing Cyano-Terminated Phenyl Benzoate Moieties

Block copolymers, known for their capacity to undergo microphase separation, spontaneously yield various periodic nanostructures. These precisely controlled nanostructures have attracted considerable interest due to their potential applications in microfabrication templates, conducting films, filter membranes, and other areas. However, it is crucial to acknowledge that microphase-separated structures typically exhibit random alignment, making alignment control a pivotal factor in functional material development. To address this challenge, researchers have explored the use of block copolymers containing liquid-crystalline (LC) polymers, which offer a promising technique for alignment control. The molecular structure and LC behavior of these polymers significantly impact the morphology and alignment of microphase-separated structures. In this study, we synthesized LC diblock copolymers with cyano-terminated phenyl benzoate moieties and evaluated the microphase-separated structures and molecular alignment behaviors. The LC diblock copolymers with a narrow molecular weight distribution were synthesized by atom transfer radical polymerization. Small angle X-ray scattering measurements revealed that the block copolymers exhibit smectic LC phases and form cylinder structures with a lattice period of about 18 nm by microphase separation. The examination of block copolymer films using polarized optical microscopy and polarized UV-visible absorption spectroscopy corroborated that the LC moieties were uniaxially aligned along the alignment treatment direction.

Thickness-dependent carrier polarity of MoTe2 transistors with NiTe2 semimetal contacts

We demonstrated that the carrier polarity of MoTe2 transistors can be modulated by controlling the channel thickness with NiTe2 semimetal contacts. The multilayer MoTe2 transistors (thickness >7.1 nm) exhibit a symmetric ambipolar conduction, and a transition to unipolar p-type polarity occurs as the channel thickness decreased down to ∼2.3 nm. The position of the semimetal NiTe2 work function was verified to be located at the mid-gap of multilayer MoTe2, and the observed transition was interpreted by a synergistic effect of the channel thickness-dependent band alignment and charge transfer behavior with unique NiTe2 semimetal contacts.

Macroscopic traffic characterization based on driver memory and traffic stimuli

A new macroscopic traffic flow model is proposed which incorporates traffic alignment behavior at transitions. In this model, velocity is a function of the distance headway and driver response time. It can be used to characterize the traffic flow for both uniform and non uniform headways. The well-known Zhang model characterizes this flow based on driver memory which can produce unrealistic results. The performance of the proposed Khan-Imran-Gulliver (KIG) and Zhang models is evaluated for an inactive bottleneck on a 2000 m circular road. The results obtained show that the traffic behavior with the KIG model is more realistic.

Approximate simulation of cortical microtubule models using dynamical graph grammars

Dynamical graph grammars (DGGs) are capable of modeling and simulating the dynamics of the cortical microtubule array (CMA) in plant cells by using an exact simulation algorithm derived from a master equation; however, the exact method is slow for large systems. We present preliminary work on an approximate simulation algorithm that is compatible with the DGG formalism. The approximate simulation algorithm uses a spatial decomposition of the domain at the level of the system’s time-evolution operator, to gain efficiency at the cost of some reactions firing out of order, which may introduce errors. The decomposition is more coarsely partitioned by effective dimension (d = 0 to 2 or 0 to 3), to promote exact parallelism between different subdomains within a dimension, where most computing will happen, and to confine errors to the interactions between adjacent subdomains of different effective dimensions. To demonstrate these principles we implement a prototype simulator, and run three simple experiments using a DGG for testing the viability of simulating the CMA. We find evidence indicating the initial formulation of the approximate algorithm is substantially faster than the exact algorithm, and one experiment leads to network formation in the long-time behavior, whereas another leads to a long-time behavior of local alignment.

Robust distributed control within a curve virtual tube for a robotic swarm under self‐localization drift and precise relative navigation

AbstractTo guide the movement of a robotic swarm in a corridor‐like environment, a curve virtual tube with no obstacle inside was designed in our previous work. This article generalizes the controller design to the condition that all robots have self‐localization drifts and precise relative navigation, where the flocking algorithm is introduced to reduce the negative impact of the self‐localization drift. Similar to the “many wrongs principle,” it is shown that the cohesion behavior and the velocity alignment behavior are able to reduce the influence of the position measurement drift and the velocity measurement error, respectively. For convenience in practical use, a modified vector field controller with five control terms is put forward. Finally, the effectiveness of the proposed method is validated by numerical simulations and real experiments.

Alignment behavior of nerve, vascular, muscle, and intestine cells in two- and three-dimensional strategies.

By harnessing structural hierarchical insights, plausibly simulate better ones imagination to figure out the best choice of methods for reaching out the unprecedented developments of the tissue engineering products as a next level. Constructing a functional tissue that incorporates two-dimensional (2D) or higher dimensions requires overcoming technological or biological limitations in order to orchestrate the structural compilation of one-dimensional and 2D sheets (microstructures) simultaneously (in situ). This approach enables the creation of a layered structure that can be referred to as an ensemble of layers or, after several days of maturation, a direct or indirect joining of layers. Here, we have avoided providing a detailed methodological description of three-dimensional and 2D strategies, except for a few interesting examples that highlight the higher alignment of cells and emphasize rarely remembered facts associated with vascular, peripheral nerve, muscle, and intestine tissues. The effective directionality of cells in conjunction with geometric cues (in the range of micrometers) is well known to affect a variety of cell behaviors. The curvature of a cell's environment is one of the factors that influence the formation of patterns within tissues. The text will cover cell types containing some level of stemness, which will be followed by their consequences for tissue formation. Other important considerations pertain to cytoskeleton traction forces, cell organelle positioning, and cell migration. An overview of cell alignment along with several pivotal molecular and cellular level concepts, such as mechanotransduction, chirality, and curvature of structure effects on cell alignments will be presented. The mechanotransduction term will be used here in the context of the sensing capability that cells show as a result of force-induced changes either at the conformational or the organizational levels, a capability that allows us to modify cell fate by triggering downstream signaling pathways. A discussion of the cells' cytoskeleton and of the stress fibers involvement in altering the cell's circumferential constitution behavior (alignment) based on exposed scaffold radius will be provided. Curvatures with size similarities in the range of cell sizes cause the cell's behavior to act as if it was in an in vivo tissue environment. The revision of the literature, patents, and clinical trials performed for the present study shows that there is a clear need for translational research through the implementation of clinical trial platforms that address the tissue engineering possibilities raised in the current revision. This article is categorized under: Infectious Diseases > Biomedical Engineering Neurological Diseases > Biomedical Engineering Cardiovascular Diseases > Biomedical Engineering.

The critical role of interfacial Coulomb force in the orientation alignment behavior of lubricant molecules

The non-bonding interactions of four interfaces with typical polar interfacial characteristics are simulated using molecular dynamics methods. The Coulomb and Van der Waals terms in the optimized potentials for liquid simulations all-atom (OPLS_AA) force field are distinguished and their effects on the arrangement behavior of the lubricant molecules are investigated. A mathematical model is proposed to quantitatively characterize the influence on the tilt degree of lubricant molecules (PAO4 and PEG200) near the nano-silica surfaces. The tilt degree of the lubricant molecules at the interface is determined by the molecular chain tilt factor γ, which is calculated by combining the "polar characteristics of the solid surface", the characteristics of the "polar units" within the liquid molecules, and the linking modes between them.

The mechanical alignment of dust (MAD)

Context. Observations of polarized light emerging from aligned dust grains are commonly exploited to probe the magnetic field orientation in astrophysical environments. However, the exact physical processes that result in a coherent large-scale grain alignment are still far from being fully constrained. Aims. In this work, we aim to investigate the impact of a gas-dust drift on a microscopic level, potentially leading to a mechanical alignment of fractal dust grains and subsequently to dust polarization. Methods. We scanned a wide range of parameters of fractal dust aggregates in order to statistically analyze the average grain alignment behavior of distinct grain ensembles. In detail, the spin-up efficiencies for individual aggregates were determined utilizing a Monte Carlo approach to simulate the collision, scattering, sticking, and evaporation processes of gas on the grain surface. Furthermore, the rotational disruption of dust grains was taken into account to estimate the upper limit of possible grain rotation. The spin-up efficiencies were analyzed within a mathematical framework of grain alignment dynamics in order to identify long-term stable grain alignment points in the parameter space. Here, we distinguish between the cases of grain alignment in the direction of the gas-dust drift and the alignment along the magnetic field lines. Finally, the net dust polarization was calculated for each collection of stable alignment points per grain ensemble. Results. We find the purely mechanical spin-up processes within the cold neutral medium to be sufficient enough to drive elongated grains to a stable alignment. The most likely mechanical grain alignment configuration is with a rotation axis parallel to the drift direction. Here, roundish grains require a supersonic drift velocity, while rod-like elongated grains can already align for subsonic conditions. We predict a possible dust polarization efficiency in the order of unity resulting from mechanical alignment. Furthermore, a supersonic drift may result in a rapid grain rotation where dust grains may become rotationally disrupted by centrifugal forces. Hence, the net contribution of such a grain ensemble to polarization drastically reduces. In the presence of a magnetic field, the drift velocity required for the most elongated grains to reach a stable alignment is roughly one order of magnitude higher compared to the purely mechanical case. We demonstrate that a considerable fraction of a grain ensemble can stably align with the magnetic field lines and report a possible dust polarization efficiency of 0.6–0.9, indicating that a gas-dust drift alone can provide the conditions required to observationally probe the magnetic field structure. We predict that magnetic field alignment is highly inefficient when the direction of the gas-dust drift and magnetic field lines are perpendicular. Conclusions. Our results strongly suggest that mechanical alignment has to be taken into consideration as an alternative driving mechanism where the canonical radiative torque alignment theory fails to account for the full spectrum of available dust polarization observations.

Electrooptical switching and photopatterning of luminescence in nematic liquid crystals doped with mesogenic europium complex

Stimuli-responsive self-organized soft matter such as liquid crystals, polymers, gels attracts great attention due to a variety of possible applications in modern technologies. Electroinduced hydrodynamic (EHD) instability in liquid crystals is one of long-discovered effects that shows a great potential for future applications. However, this effect is insufficiently studied and its practical implementation has yet to be found. In the present paper, we applied an EHD instability to tuning luminescent properties of nematic mixtures doped with a highly emissive europium complex, which has good solubility in a liquid crystalline (LC) matrix and high quantum yield of luminescence. Nematic mixtures studied in this work possess negative anisotropy of dielectric constant and positive anisotropy of conductivity that allow for observing convective EHD patterns induced by ionic conductivity. The influence of field frequency on the threshold voltage was studied and optimal conditions for induction of EHD patterns were determined. The luminescence intensity was found to substantially decrease or increase under an applied electric field depending on the alignment behavior of LC molecules inside the cells and the angle of observation. In a tilted cell (60°), the emission intensity gradually increases under applied electric field and reaches values ca. 2.5 times higher than in zero field conditions. This phenomenon is associated with alignment of the europium complex molecules along electric field direction (cooperatively with LC molecules) and EHD-induced light scattering. Kinetics of electrooptic switching was studied and different approaches to luminescence photopatterning of the studied nematic mixture with polymerizable monoacrylate and diacrylate were demonstrated.

In-Vitro Study of Indium (III) Sulfate-Containing Medium on the Viability and Adhesion Behaviors of Human Dermal Fibroblast on Engineered Surfaces.

Tissues and organs consist of cells organized in specified patterns that support their function, as exemplified by tissues such as skin, muscle, and cornea. It is, therefore, important to understand how external cues, such as engineered surfaces or chemical contaminants, can influence the organization and morphology of cells. In this work, we studied the impact of indium sulfate on human dermal fibroblast (GM5565) viability, production of reactive oxygen species (ROS), morphology, and alignment behavior on tantalum/silicon oxide parallel line/trench surface structures. The viability of cells was measured using the alamarBlue™ Cell Viability Reagent probe, while the ROS levels in cells were quantified using cell-permeant 2',7'-dichlorodihydrofluorescein diacetate. Cell morphology and orientation on the engineered surfaces were characterized using fluorescence confocal and scanning electron microscopy. When cells were cultured in media containing indium (III) sulfate, the average cell viability decreased by as much as ~32% and the concentration of cellular ROS increased. Cell geometry became more circular and compact in the presence of indium sulfate. Even though actin microfilaments continue to preferentially adhere to tantalum-coated trenches in the presence of indium sulfate, the cells are less able to orient along the line axes of the chips. Interestingly, the indium sulfate-induced changes in cell alignment behavior are pattern dependent-a larger proportion of adherent cells on structures with line/trench widths in the range of 1 μm and 10 μm lose the ability to orient themselves, compared to those grown on structures with line widths smaller than 0.5 μm. Our results show that indium sulfate impacts the response of human fibroblasts to the surface structure to which they adhere and underscores the importance of evaluating cell behaviors on textured surfaces, especially in the presence of potential chemical contaminants.

Pair Interaction between Two Catalytically Active Colloids.

Due to the intrinsically complex non-equilibrium behavior of the constituents of active matter systems, a comprehensive understanding of their collective properties is a challenge that requires systematic bottom-up characterization of the individual components and their interactions. For self-propelled particles, intrinsic complexity stems from the fact that the polar nature of the colloids necessitates that the interactions depend on positions and orientations of the particles, leading to a 2d - 1 dimensional configuration space for each particle, in d dimensions. Moreover, the interactions between such non-equilibrium colloids are generically non-reciprocal, which makes the characterization even more complex. Therefore, derivation of generic rules that enable us to predict the outcomes of individual encounters as well as the ensuing collective behavior will be an important step forward. While significant advances have been made on the theoretical front, such systematic experimental characterizations using simple artificial systems with measurable parameters are scarce. Here, two different contrasting types of colloidal microswimmers are studied, which move in opposite directions and show distinctly different interactions. To facilitate the extraction of parameters, an experimental platform is introduced in which these parameters are confined on a 1D track. Furthermore, a theoretical model for interparticle interactions near a substrate is developed, including both phoretic and hydrodynamic effects, which reproduces their behavior. For subsequent validation, the degrees of freedom are increased to 2D motion and resulting trajectories are predicted, finding remarkable agreement. These results may prove useful in characterizing the overall alignment behavior of interacting self-propelling active swimmer and may find direct applications in guiding the design of active-matter systems involving phoretic and hydrodynamicinteractions.

Swarming: hydrodynamic alignment with pressure

We study the swarming behavior of hydrodynamic alignment. Alignment reflects steering toward a weighted average heading. We consider the class of so-called p p -alignment hydrodynamics, based on 2 p 2p -Laplacians and weighted by a general family of symmetric communication kernels. The main new aspect here is the long-time emergence behavior for a general class of pressure tensors without a closure assumption, beyond the mere requirement that they form an energy dissipative process. We refer to such pressure laws as “entropic”, and prove the flocking of p p -alignment hydrodynamics, driven by singular kernels with a general class of entropic pressure tensors. These results indicate the rigidity of alignment in driving long-time flocking behavior despite the lack of thermodynamic closure.

A Physical Model to Describe the Motion Behavior of BNNSs under Nanosecond Pulses.

This paper presents a physical model that provides a comprehensive understanding of the motion behavior of boron nitride nanosheets (BNNSs) immersed in ultrapure deionized water and subjected to a series of nanosecond pulses. In a study conducted by Y. Mi et al. The authors explored the global alignment behavior of BNNSs and fitted the experimental data with an exponential decay function. However, this function lacks clear physical mechanisms and the significance of the fitting parameters remains unclear. To address this issue, we have developed a kinetic model that explicitly describes the underlying physical mechanisms. Furthermore, we propose a simplified mathematical model that not only predicts the displacement of BNNSs but also estimates the total time, velocity, and acceleration of the motion process.