Thermal Roughening and Deroughening at Polymer Interfaces in Electrophoretic Deposition

Thermal scaling and relaxation of the interface width in an electrophoretic deposition of polymer chains is examined by a three-dimensional Monte Carlo simulation on a discrete lattice. Variation of the equilibrium interface width $W_r$ with the temperature $T$ shows deroughening $W_r \propto T^{-\delta}$, with $\delta \sim 1/4$, at low temperatures and roughening $W_r \propto T^{\nu}$, with $\nu \sim 0.4$ at high temperatures. The roughening-deroughening transition temperature $T_t$ increases with longer chain lengths and is reduced by using the slower segmental dynamics.Comment: This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may appl

Texture, twinning and metastable "tetragonal" phase in ultrathin films of HfO₂ on a Si substrate

Thin HfO<sub>2</sub> films grown on the lightly oxidised surface of (100) Si wafers have been examined using dark-field transmission electron microscopy and selected area electron diffraction in plan view. The polycrystalline film has a grain size of the order of 100 nm and many of the grains show evidence of twinning on (110) and (001) planes. Diffraction studies showed that the film had a strong [110] out-of-plane texture, and that a tiny volume fraction of a metastable (possibly tetragonal) phase was retained. The reasons for the texture, twinning and the retention of the metastable phase are discussed

Interface Relaxation in Electrophoretic Deposition of Polymer Chains: Effects of Segmental Dynamics, Molecular Weight, and Field

Using different segmental dynamics and relaxation, characteristics of the interface growth is examined in an electrophoretic deposition of polymer chains on a three (2+1)-dimensional discrete lattice with a Monte Carlo simulation. Incorporation of faster modes such as crankshaft and reptation movements along with the relatively slow kink-jump dynamics seems crucial in relaxing the interface width. As the continuously released polymer chains are driven (via segmental movements) and deposited, the interface width W grows with the number of time steps t, W∝tβ, (β ~0.4-0.8), which is followed by its saturation to a steady-state value Ws. Stopping the release of additional chains after saturation while continuing the segmental movements relaxes the saturated width to an equilibrium value (Ws → Wr). Scaling of the relaxed interface width Wr with the driving field E, Wr∝E-1/2 remains similar to that of the steady-state Ws width. In contrast to monotonic increase of the steady-state width Ws, the relaxed interface width Wr is found to decay (possibly as a stretched exponential) with the molecular weight

Roughening, Deroughening, and Nonuniversal Scaling of the Interface Width in Electrophoretic Deposition of Polymer Chains

Growth and roughness of the interface of deposited polymer chains driven by a field onto an impenetrable adsorbing surface are studied by computer simulations in (2 + 1) dimensions. The evolution of the interface width W shows a crossover from short-time growth described by the exponent beta(1) to a long-time growth with exponent beta(2) (\u3ebeta(1)) Tne saturated width increases, i.e., the interface roughens, with the molecular weight L-c, but the roughness exponent alpha (from W-s similar to L-alpha) becomes negative in contrast to models for particle deposition; cr depends on the chain length-a nonuniversal scaling with the substrate length L. Roughening and deroughening occur as the field E and the temperature T compete such that W-s approximate to (A+BT)E-1/2

A Study on the Ability of the Second Year Students of Sman 15 Pekanbaru in Comprehending Narrative Texts

This descriptive research was aimed to find out the ability of the second year students of SMAN 15 Pekanbaru in comprehending narrative texts. The subject of this research was class XI IPS 1 which consisted of 32 students. The data were collected by administering a test to the students in the form of multiple choice test. The findings of the research are as following: finding the main idea (75.00), finding the factual information in complication (65.63), finding the factual information in resolution (70.63), finding the meaning of vocabulary (67.50), finding references (71.88), finding inference (51.25), finding social function (73.13). As a conclusion, the highest score was in finding the main ideas (75.00) which categorized into good level, and the lowest score was in finding inference (51.25) which categorized into mediocre level. The implication of the finding is that the second year students of SMAN 15 Pekanbaru should improve their reading skills in order to reach excellent level

Grain boundaries in polycrystalline materials for energy applications: First principles modeling and electron microscopy

\ua9 2024 Author(s). Polycrystalline materials are ubiquitous in technology, and grain boundaries have long been known to affect materials properties and performance. First principles materials modeling and electron microscopy methods are powerful and highly complementary for investigating the atomic scale structure and properties of grain boundaries. In this review, we provide an introduction to key concepts and approaches for investigating grain boundaries using these methods. We also provide a number of case studies providing examples of their application to understand the impact of grain boundaries for a range of energy materials. Most of the materials presented are of interest for photovoltaic and photoelectrochemical applications and so we include a more in depth discussion of how modeling and electron microscopy can be employed to understand the impact of grain boundaries on the behavior of photoexcited electrons and holes (including carrier transport and recombination). However, we also include discussion of materials relevant to rechargeable batteries as another important class of materials for energy applications. We conclude the review with a discussion of outstanding challenges in the field and the exciting prospects for progress in the coming years

Conformational Temperature-Dependent Behavior of a Histone H2AX: A Coarse-Grained Monte Carlo Approach Via Knowledge-Based Interaction Potentials

Histone proteins are not only important due to their vital role in cellular processes such as DNA compaction, replication and repair but also show intriguing structural properties that might be exploited for bioengineering purposes such as the development of nano-materials. Based on their biological and technological implications, it is interesting to investigate the structural properties of proteins as a function of temperature. In this work, we study the spatial response dynamics of the histone H2AX, consisting of 143 residues, by a coarse-grained bond fluctuating model for a broad range of normalized temperatures. A knowledge-based interaction matrix is used as input for the residue-residue Lennard-Jones potential. A knowledge-based interaction matrix is used as input for the residue-residue Lennard-Jones potential. We find a variety of equilibrium structures including global globular configurations at low normalized temperature (T* = 0.014), combination of segmental globules and elongated chains (T* = 0.016,0.017), predominantly elongated chains (T* = 0.019,0.020), as well as universal SAW conformations at high normalized temperature (T* ≥= 0.023). The radius of gyration of the protein exhibits a non-monotonic temperature dependence with a maximum at a characteristic temperature (T-c* = 0.019) where a crossover occurs from a positive (stretching at T*≤T*c) thermal response on increasing T*

Preface

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