bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface-induced ordering for confined random block copolymers
Authors: Gutman Lorin , Chakraborty Arup K. 
Published: July 2002

Motivated by practical issues that pertain to polymer adhesion, we consider the equilibrium behavior of a dilute solution of ideal A–B random block copolymers confined between two solid surfaces. We develop a general theory for the situation wherein the A–A, B–B, and A–B intersegment interactions are different, and furthermore, the A and B segments interact differently with the solid surfaces. Random block copolymers constitute a class of materials wherein a quenched disorder (the sequence distribution) is carried by the fluid whose statistical properties are of interest. In our theory, we perform quenched disorder averages using the replica trick. The nonlocal terms in our action functional are decoupled by introducing a set of random fields. The resulting equations for the propagator are analyzed within the framework of eigenfunction expansions. Since we consider long chains in confined geometries, we invoke the ground state approximation. We also carry out the functional integrals over the random fields using saddle points.
Our theory does not treat the segment–surface interactions within a mean field approximation. Our analysis leads to a set of nonlinear self-consistent-field equations. We have solved our general equations numerically for a particular problem. In order to isolate and highlight the effects of dissimilar segment–surface interactions, we consider a case wherein the intersegment interactions are all alike (of the excluded volume type), while the A segments are attracted to the solid surfaces and the B units are repelled. For this specific problem we find that, above a threshold value of the fraction of attractive segments, significant microphase ordering is induced by the surface. This leads to damped oscillations in the composition profile. This onset of significant surface-induced composition fluctuations is accompanied by an ‘‘adsorption–desorption transition’’ which corresponds to a qualitative change in the shape of the total segment density profile. These and other results are discussed and the experimentally testable consequences of our predictions are elucidated. Our results are in agreement with recent simulation studies. We suggest specific experiments that may shed further light on the physical phenomena revealed by our calculations.
Ab initio study of the three lowest-lying (X 1Σ+, 3Σ+, and 1Σ+) electronic states of AgF
Authors: Ramirez-Solis A. , Schamps J. 
Published: July 2002

Ab-initio pseudopotential two-configuration self-consistent field followed by extensive variational and perturbational second order Mo/ller–Plesset multireference configuration interaction calculations using localized molecular orbitals were performed to characterize the structure and adiabatic potential energy curves of the three lowest (X 1Σ+, 3Σ+, and 1Σ+) purely electronic states of the AgF molecule. Spin-orbit interactions were introduced semiempirically in a second step. The very strong coupling of the neutral Ag(4d105s1)F(2s22p5) and ionic Ag+(4d95s1)F−(2s22p6) configurations at rather short internuclear distance for both excited 3,1Σ+ states is responsible for the appearance of very shallow minima, thus leading to a limited number of stable vibrational levels for these excited states as suggested previously for the AO+ state. In contrast with the CuF molecule, where only the ionic configuration Cu+(3,1D)F−(1S) is present in the 3,1Σ+ states, this coupling of ionic and neutral structures in AgF is explained by the relative positions of the valence orbital energies of the neutral Cu and Ag atoms with respect to the 2p level of the halogen atom. These results lead to the assignment of the observed AO+–X 1Σ+ transition as a 1Σ+–1Σ+ type transition.
The very recently observed aΩ1 and A′Ω1 states are shown to be, respectively, the Ω=O− and Ω=1 spin–orbit components of the 3Σ+ state, which justifies the relabeling of aΩ1 into a aΩO−. The calculated spin–orbit-induced splitting between these two components is in excellent agreement with the observed one after reconsidering spectroscopic data. For all these states the calculated spectroscopic constants are in good agreement with available experimental data. The fourth experimental state, BO+, is probably not correlated with the 3Π valence state as previously suggested but it could rather correspond to a Rydberg ionic state involving the Ag+(4d95p)F−(2s22p6) structure.
Simple expressions for radial functions appearing in the expansions of 𝒴m1l1 (∇)F m2l2(r) and ∇2n𝒴m1l1(∇)F m2l2 (r)
Authors: Rashid M. A. 
Published: July 2002

In this paper, simple analytic expressions for the radial functions r ll1l2( f (r)) and Glnl1l2( f (r)), which appear in the expressions for 𝒴m1l1(∇) fl2(r) Ym2l2(r̂) and ∇2n𝒴m1l1(∇) fl2(r) Ym2l2(r̂) when expressed as linear combinations of Yml(r̂), where 𝒴m1l1(∇) is obtained from the solid harmonic 𝒴m1l1(r) =r l1Ym1l1(r̂), are derived by replacing x, y, and z in its representation as a polynomial of degree l1 by ∂/∂x, ∂/∂y, and ∂/∂z, respectively.
Writing r ll1l2( f (r)) =r ll1l20(r) f (r) and Glnl1l2( f (r)) =Glnl1l20(r) f (r), the expression for r ll1l20(r) (Glnl1l20(r)) is found to be (2/r)l1((2/r)l1+2n) times a product of commuting factors containing the single operator 1/2 r(d/dr) and not two noncommuting operators r and (1/r)(d/dr) in the many equivalent previously obtained results which are thus synthesized in this approach. Also, expressions for these operators manifest the symmetries in the problem. In addition, a simple connection Glnl1l20(r) =r ll1+2nl20(r) between these two operators and the corresponding radial functions Glnl1l2( f (r)) and r ll1l2( f (r)) are found.
A global study of enhanced stretching and diffusion in chaotic tangles
Authors: Beigie Darin , Leonard Anthony , Wiggins Stephen 
Published: July 2002

A global, finite-time study is made of stretching and diffusion in a class of chaotic tangles associated with fluids described by periodically forced two-dimensional dynamical systems. Invariant lobe structures formed by intersecting global stable and unstable manifolds of persisting invariant hyperbolic sets provide the geometrical framework for studying stretching of interfaces and diffusion of passive scalars across these interfaces. In particular, the present study focuses on the material curve that initially lies on the unstable manifold segment of the boundary of the entraining turnstile lobe.
A knowledge of the stretch profile of a corresponding curve that evolves according to the unperturbed flow, coupled with an appreciation of a symbolic dynamics that applies to the entire original material curve in the perturbed flow, provides the framework for understanding the mechanism for, and topology of, enhanced stretching in chaotic tangles. Secondary intersection points (SIP’s) of the stable and unstable manifolds are particularly relevant to the topology, and the perturbed stretch profile is understood in terms of the unperturbed stretch profile approximately repeating itself on smaller and smaller scales. For sufficiently thin diffusion zones, diffusion of passive scalars across interfaces can be treated as a one-dimensional process, and diffusion rates across interfaces are directly related to the stretch history of the interface.
An understanding of interface stretching thus directly translates to an understanding of diffusion across interfaces. However, a notable exception to the thin diffusion zone approximation occurs when an interface folds on top of itself so that neighboring diffusion zones overlap. An analysis which takes into account the overlap of nearest neighbor diffusion zones is presented, which is sufficient to capture new phenomena relevant to efficiency of mixing. The analysis adds to the concentration profile a saturation term that depends on the distance between neighboring segments of the interface. Efficiency of diffusion thus depends not only on efficiency of stretching along the interface, but on how this stretching is distributed relative to the distance between neighboring segments of the interface.
The impedance and energy efficiency of a coaxial magnetized plasma source used for spheromak formation and sustainment
Authors: Barnes Cris W. , Jarboe T. R. , Marklin G. J. , Knox S. O. , Henins I. 
Published: July 2002

Electrostatic (dc) helicity injection has previously been shown to successfully sustain the magnetic fields of spheromaks and tokamaks. The magnitude of the injected magnetic helicity balances (within experimental error) the flux lost by resistive decay of the toroidal equilibrium. Hence the problem of optimizing this current drive scheme involves maximizing the injected helicity (the voltage-connecting-flux product) while minimizing the current (which multiplied by the voltage represents the energy input and also possible damage to the electrodes). The impedance (voltage-to-current ratio) and energy efficiency of a dc helicity injection experiment are studied on the CTX spheromak [Phys. Fluids 29, 3415 (1986)]. Over several years changes were made in the physical geometry of the coaxial magnetized plasma source as well as changes in the external electrical circuit. The source could be operated over a wide range of external charging voltage (and hence current), applied axial flux, and source gas flow rate.
A database of resulting voltage, helicity injection, efficiency, electron density, and rotation has been created. These experimental results are compared to an ideal magnetohydrodynamic theory of magnetic flux flow. The theory is parametrized by the dimensionless Hall parameter, the ratio of electric to mass current. For a constant Hall parameter the theory explains why the voltage depends quadratically on the current at constant flux. The theory also explains the approximately linear dependence of the impedance-to-current ratio on the current-to-flux ratio of the source. The current-to-flux ratio itself (the energy-per-unit helicity of the source) is bounded below by considerations of force balance. While the rotation of the flow is not understood, the density of the sustained spheromak is shown to be related to the mass flow in the source, supporting the constant Hall parameter assumption. The overall efficiency of sustainment through dc helicity injection is limited by the usual Ohmic resistive decay, by the force-balance limits on the current-to-flux ratio, by the losses of the external electrical circuit, and by the fundamental limitations on the achievable impedance of flux flow in a magnetized plasma. Even so, ratios of spheromak magnetic energy to capacitor bank energy of over 17% have been achieved on CTX. Ignoring external circuit losses the efficiency of electrostatic helicity injection for converting energy received by the coaxial source to the energy of the spheromak magnetic field has exceeded 70%.
Dosimetric feasibility of hippocampal avoidance whole brain radiotherapy with an MRI‐guided linear accelerator
Authors: Graham Jasmine A. , Redler Gage , Delozier Kirby B. , Yu Hsiang‐Hsuan Michael , Oliver Daniel E. , Rosenberg Stephen A. 
Published: March 2022

AbstractPurpose/Objective(s)Whole brain radiotherapy with hippocampal avoidance (HA‐WBRT) is a technique utilized to treat metastatic brain disease while preserving memory and neurocognitive function. We hypothesized that the treatment planning and delivery of HA‐WBRT plans is feasible with an MRI‐guided linear accelerator (linac) and compared plan results with clinical non‐MRI‐guided C‐Arm linac plans.Materials/MethodsTwelve HA‐WBRT patients treated on a non‐MRI‐guided C‐Arm linac were selected for retrospective analysis. Treatment plans were developed using a 0.35T MRI‐guided linac system for comparison to clinical plans. Treatment planning goals were defined as provided in the Phase II Trial NRG CC001. MRI‐guided radiotherapy (MRgRT) treatment plans were developed by a dosimetrist and compared with clinical plans. quality assurance (QA) plans were generated and delivered on the MRI‐guided linac to a cylindrical diode detector array. Planning target volume (PTV) coverage was normalized to ∼95% to provide a control point for comparison of dose to the organs at risk.ResultsMRgRT plans were deliverable and met all clinical goals. Mean values demonstrated that the clinical plans were less heterogeneous than MRgRT plans with mean PTV V37.5 Gy of 0.00% and 0.03% (p = 0.013), respectively. Average hippocampi maximum doses were 14.19 ± 1.29 Gy and 15.00 ± 1.51 Gy, respectively. The gamma analysis comparing planned and measured doses resulted in a mean of 99.9% ± 0.12% of passing points (3%/2mm criteria). MRgRT plans had an average of 38.33 beams with average total delivery time and beam‐on time of 13.7 (11.2–17.5) min and 4.1 (3.2–5.4) min, respectively. Clinical plan delivery times ranged from 3 to 7 min depending on the number of noncoplanar arcs. Planning time between the clinical and MRgRT plans was comparable.ConclusionThis study demonstrates that HA‐WBRT can be treated using an MRI‐guided linear accelerator with comparable treatment plan quality and delivery accuracy.
Reconfigurable and Efficient Implementation of 16 Boolean Logics and Full‐Adder Functions with Memristor Crossbar for Beyond von Neumann In‐Memory Computing
Authors: Song Yujie , Wang Xingsheng , Wu Qiwen , Yang Fan , Wang Chengxu , Wang Meiqing , Miao Xiangshui 
Published: March 2022

AbstractThe rise of emerging technologies such as Big Data, the Internet of Things, and artificial intelligence, which requires efficient power schemes, is driving brainstorming in data computing and storage technologies. In this study, merely relying on the fundamental structure of two memristors and a resistor, arbitrary Boolean logic can be reconfigured and calculated in two steps, while no additional voltage sources are needed beyond “±VP” and 0, and all state reversals are based on memristor set switching. Utilizing the proposed logic scheme in an elegant form of unity structure and minimum cost, the implementation of a 1‐bit adder is demonstrated economically, and a promising circuit scheme for the N‐bit adder is exhibited. Some critical issues including the crosstalk problem, energy consumption, and peripheral circuits are further simulated and discussed. Compared with existing works on memristive logic, such methods support building a memristor‐based digital in‐memory calculation system with high functional reconfigurability, simple voltage sources, and low power and area consumption.
As(III)‐to‐As(V) Oxidation in Copper Smelter Wastewater by In Situ‐Generated Ozone
Authors: Hansen Henrik K. , Neira Zenovia , Gutiérrez Claudia , Lazo Andrea , Lazo Pamela , Hansen Marcela E. , Ollino Mario , Caneo Cecilia , Ottosen Lisbeth M. 
Published: March 2022

AbstractAs(III) is the most common arsenic species in copper smelter wastewater but is difficult to remove, and an oxidation to As(V) is desirable. The oxidation of As(III) to As(V) in copper smelter wastewater was studied using in situ‐generated ozone, which has a high oxidation capacity and does not create secondary contaminants. With the aim to determine adequate conditions for As(III) oxidation, experiments considering pH, ozonation time, and oxygen flow rate as variables were done. Experimental tests showed that the best pH was at 2 and with a moderate oxygen flow rate. The complete oxidation of As(III) in both synthetic wastewater and real wastewater was achieved nearly after the same time of ozonation. Pseudo‐first‐order kinetics could model the As(III)‐to‐As(V) oxidation by ozone.
Meta‐heuristic optimization algorithms for placement of multiple nulls and minimization of side lobe level in quadrant symmetric sparse array antenna
Authors: Dutta Kailash P. , Misra Bitan , Mahanti Gautam K. 
Published: March 2022

SummaryThe optimization of the non‐uniform planar array antenna parameter in order to minimize the signal interference in the electromagnetic environment through null placement is one of the most important areas of investigation in the field of wireless communication. This study deals with an effective method of synthesis of a quadrant symmetric sparse planar array antenna using the novel implementation of the well‐known meta‐heuristic optimization algorithms, namely, symbiotic organism search (SOS) and moth flame optimization (MFO) algorithms. The objective of this work is to place multiple small and wide nulls at the desired angles and simultaneously minimize the side lobe levels using a nonlinear mathematical approach. Three examples are presented with constraints that include the inter‐elemental distance, fixed number of array elements in the aperture, and the aperture size. The radiating antenna array elements are considered to have fixed uniform current distribution. The meta‐heuristic optimization approach offers the advantages of avoiding the infeasible solution while finding the best optimal set of element positions to reduce side lobe level in the desired radiation pattern. The radiation pattern characteristics and the computation time associated with each example and each algorithm are recorded and compared for arriving at the conclusion. The superiority of SOS is found in terms of the optimized side lobe levels. At the same time, both algorithms are found to be efficient in positioning the symmetric nulls in desired locations in the radiation pattern successfully. When compared with the published papers, proposed approach yields better results confirming the effectiveness of the performance of these algorithms.
Chronic early‐life stress increases cognitive impulsivity and D2 immunoreactivity in the nucleus accumbens of adult rats
Authors: Laguna Arturo , Lajud Naima , Juárez Jorge , Sanz‐Martin Araceli 
Published: March 2022

AbstractChronic early life stress (ECS) induced by limited bedding and nesting (LBN) material in rodents is a naturalistic stress model that mimics many of the behavioral and neural consequences of child abuse and neglect; however, the effect of ECS on adult impulsivity has never been studied. The aim of our work was to determine the effects of ECS on cognitive impulsivity and its relation to D2 immunoreactivity in the nucleus accumbens (NAc) and prefrontal cortex (PFC) of adult male rats. Sprague–Dawley rats were exposed to LBN from postnatal day 2 to 9. We evaluated dams’ maternal behavior and offspring corticosterone levels. The rats’ impulsive cognitive behavior was evaluated by a delay‐discounting task (transitional bridge) on P70, and we evaluated D2 receptors by immunostaining. Our results indicated that ECS affected maternal behavior in the dams and increased pups’ corticosterone levels at P9, but not in adults. ECS rats showed lower frequencies of choosing the delayed reinforcer and shorter latencies to cross on the delay‐discounting task. In addition, ECS rats showed increased D2 immunoreactivity in the NAc when compared with controls. Our data suggest that ECS can cause impulsive behaviors in adult rats characterized by less convenient choices, likely related to an increase in D2 receptors in the NAc. These findings could contribute to our understanding of the effects of child abuse and neglect on impulsive behavior.
Infants’ neural sensitivity to social interactions varies by income and infant‐directed speech
Authors: Lopera‐Perez Diana C. , Nayak Srishti , Stangier Giulia , Tuladhar Charu T. , St. John Ashley M. , Grieve Philip G. , Tarullo Amanda R. 
Published: March 2022

AbstractSocial interactions are essential for infant brain development, yet we know little about how infant functional connectivity differs between social and nonsocial contexts, or how sensitivity to differences between contexts might be related to early distal and proximal environmental factors. We compared 12‐month‐old infants’ intrahemispheric electroencephalographic (EEG) coherence between a social and a nonsocial condition, then examined whether differences between conditions varied as a function of family economic strain and two maternal behaviors at 6 months, positive affect and infant‐directed speech. We found lower EEG coherence from the frontal region to the central, parietal, temporal, and occipital regions during the social condition, but only for infants from higher‐income families and infants whose mothers used higher proportions of infant‐directed speech. In contrast, there were no differences between social and nonsocial conditions for infants from economically strained families or infants whose mothers used lower proportions of infant‐directed speech. This study demonstrates that neural organization differs between a nonsocial baseline and a social interaction, but said differentiation is not present for infants from less privileged backgrounds. Our results underscore the importance of examining brain activity during species‐typical contexts to understand the role of environmental factors in brain development.
Adaptive slime mould algorithm for optimal design of photovoltaic models
Authors: Lin Haiping , Ahmadianfar Iman , Amiri Golilarz Noorbakhsh , Jamei Mehdi , Heidari Ali Asghar , Kuang Fangjun , Zhang Siyang , Chen Huiling 
Published: March 2022

AbstractSolar energy is becoming more popular as it is a clean source of electricity. The design of photovoltaic (PV) cells has therefore captivated experts worldwide. The two key issues are the lack of an excellent model to define solar cells and the lack of data regarding PV cells. This scenario even impacts solar module performance (panels). The behavior of solar cells is described by the current versus voltage. Considering these values, the design challenge entails solving complicated nonlinear multimodal objectives. Different methods to figure out the parameters of the PV cells and panels have been suggested. They do not come up with the best solutions most of the time. Hence, a powerful and reliable optimizer is needed to derive the optimal parameters of these models. To this end, this study has developed an adaptive slime mould algorithm (ASMA) as a robust and precise optimization method. To implement the ASMA, four improvements are proposed: (1) a trigonometric‐based mutation and a double‐based best mutation are introduced to promote the global and local search; (2) a suitable mechanism to adaptively select the control parameters of the SMA; (3) a local escaping strategy; (4) an opposition‐based learning operator to improve the best solution. The ASMA is employed to derive optimal parameters of PV models and assessed utilizing a total number of eight well‐known optimization algorithms. The findings show that the ASMA is very competitive in terms of accuracy and convergence speed and that this is supported by a wealth of evidence. As a result, when assessing the parameters of the PV model, ASMA is a very efficient and robust optimizer. The source codes of the proposed ASMA will be uploaded for the public at http://imanahmadianfar.com and http://aliasgharheidari.com.
Patriarchy
Authors: Ortner Sherry B. 
Published: March 2022

AbstractPatriarchy is more than just “sexism.” It is a social formation of male‐gendered power with a particular structure that can be found with striking regularity in many different arenas of social life, from small‐scale contexts like the family, kin groups, and gangs, up through larger institutional contexts like the police, the military, organized religion, the state, and more. At the same time, patriarchy never stands alone, and always exists in complex intersections with other forms of power. In this article, I look at patriarchy from both points of view—that is, from both an exclusively gendered perspective, and from a perspective in which patriarchy cannot be divorced from white supremacy, normative heterosexuality, and normative able‐bodiedness. Finally I briefly consider contemporary right‐wing extremist (fascist) politics, in which the toxic intersectional brew of patriarchy, white supremacy, heteronormativity, and ideologies of bodily perfection are mobilized in pursuit of mass political control and domination.