Northwest University (United States)

About: Northwest University (United States) is a education organization based out in Kirkland, Washington, United States. It is known for research contribution in the topics: Catalysis & Crystal structure. The organization has 1230 authors who have published 911 publications receiving 6231 citations. The organization is also known as: Northwest College of the Assemblies of God.

The Optical Properties of Metal Nanoparticles: The Influence of Size, Shape, and Dielectric Environment

Abstract: The optical properties of metal nanoparticles have long been of interest in physical chemistry, starting with Faraday's investigations of colloidal gold in the middle 1800s. More recently, new lithographic techniques as well as improvements to classical wet chemistry methods have made it possible to synthesize noble metal nanoparticles with a wide range of sizes, shapes, and dielectric environments. In this feature article, we describe recent progress in the theory of nanoparticle optical properties, particularly methods for solving Maxwell's equations for light scattering from particles of arbitrary shape in a complex environment. Included is a description of the qualitative features of dipole and quadrupole plasmon resonances for spherical particles; a discussion of analytical and numerical methods for calculating extinction and scattering cross-sections, local fields, and other optical properties for nonspherical particles; and a survey of applications to problems of recent interest involving triangula...

Gold Nanoparticles for Biology and Medicine

Abstract: Gold colloids have fascinated scientists for over a century and are now heavily utilized in chemistry, biology, engineering, and medicine. Today these materials can be synthesized reproducibly, modified with seemingly limitless chemical functional groups, and, in certain cases, characterized with atomic-level precision. This Review highlights recent advances in the synthesis, bioconjugation, and cellular uses of gold nanoconjugates. There are now many examples of highly sensitive and selective assays based upon gold nanoconjugates. In recent years, focus has turned to therapeutic possibilities for such materials. Structures which behave as gene-regulating agents, drug carriers, imaging agents, and photoresponsive therapeutics have been developed and studied in the context of cells and many debilitating diseases. These structures are not simply chosen as alternatives to molecule-based systems, but rather for their new physical and chemical properties, which confer substantive advantages in cellular and medical applications.

Depositional Model of Point Bars in the Lower Wabash River

Abstract: A process-response model of point-bar sediments in the lower Wabash River of Illinois and Indiana was constructed by integration of (1) results (reported elsewhere) of repetitive hydraulic surveys of meander bends and (2) distributions of sedimentary structures and sediment size in Holocene alluvium. Vertical sequences of alluvium exposed in cutbanks and in point-bar trenches demonstrated preservation of bedform-texture patterns recognized from the hydraulic program. The depositional model is defined by distributions of three depositional facies around meander bends of disparate relative curvature. A fully developed facies assumed fully developed zones for current velocity and for bed-material size (velocity magnitude and mean size increasing from the inner bank toward the outer bank) A transitional facies incorporated transitional zones for both parameters (neither increasing outward from the inner bank). An intermediate depositional facies contained a fully developed velocity zone but a transitional size zone and was of significant extent only in gently curved bends. The latter two depositional facies differ greatly from standard facies models of meandering streams, constitute the bulk of surficial point-bar sediment in very sharply curved bends and in gently curved bends, and can be preserved preferentially by common types of bend migration. Preservation of the depositional facies of each meander bend depends upon the type of deformation (migration) the bend underwent. Limited observations from other freely meandering streams suggest that the Wabash depositional model may be widely applicable.

A Comprehensive Survey of Neural Architecture Search: Challenges and Solutions

Abstract: Deep learning has made major breakthroughs and progress in many fields. This is due to the powerful automatic representation capabilities of deep learning. It has been proved that the design of the network architecture is crucial to the feature representation of data and the final performance. In order to obtain a good feature representation of data, the researchers designed various complex network architectures. However, the design of the network architecture relies heavily on the researchers' prior knowledge and experience. Therefore, a natural idea is to reduce human intervention as much as possible and let the algorithm automatically design the architecture of the network. Thus going further to the strong intelligence. In recent years, a large number of related algorithms for \textit{Neural Architecture Search} (NAS) have emerged. They have made various improvements to the NAS algorithm, and the related research work is complicated and rich. In order to reduce the difficulty for beginners to conduct NAS-related research, a comprehensive and systematic survey on the NAS is essential. Previously related surveys began to classify existing work mainly from the basic components of NAS: search space, search strategy and evaluation strategy. This classification method is more intuitive, but it is difficult for readers to grasp the challenges and the landmark work in the middle. Therefore, in this survey, we provide a new perspective: starting with an overview of the characteristics of the earliest NAS algorithms, summarizing the problems in these early NAS algorithms, and then giving solutions for subsequent related research work. In addition, we conducted a detailed and comprehensive analysis, comparison and summary of these works. Finally, we give possible future research directions.