32,390 research outputs found
Topological metamaterials for SAW devices
No full textLAUREA MAGISTRALEI dispositivi basati su onde acustiche superficiali (Surface Acoustic Wave, SAW) sono
strumenti economici e versatili, adatti per una vasta gamma di applicazioni. I dispositivi SAW utilizzano materiali piezoelettrici per convertire un segnale elettrico in un’onda
elastica di superficie, che può essere manipolata e filtrata. Perciò, i dispositivi SAW sono
utili per filtraggio, sensoristica, attuazione, controllo del segnale nelle telecomunicazioni,
applicazioni biomediche ed industriali, e perfino nel quantum computing. La richiesta
da parte dell’industria per dispositivi SAW con migliori prestazioni, minori costi e dimensioni ridotte è in crescita. In questa tesi, l’idea tradizionale di SAW è rielaborata,
combinando la tecnologia SAW con i metamateriali topologici. L’obiettivo a lungo termine è di creare dispositivi compatti, utilizzando i vantaggi dei modi topologicamente
protetti. Il focus di questa tesi è nell’individuazione e analisi di una geometria adatta
ad ospitare un modo topologicamente protetto. Il dispositivo SAW proposto si basa sul
modello di isolatori topologici Su-Schrieffer-Heeger (SSH). Secondo il modello SSH, un
difetto in uno schieramento periodico di celle unitarie è potenzialmente adatto a ospitare
un modo topologicamente protetto, a patto che la cella unitaria abbia particolari proprietà dispersive. Il dispositivo SAW reale è composto da celle unitarie costituite da due
risonatori. Posizionando opportunamente le celle unitarie si crea un’interfaccia che materializza un percorso preferenziale per l’onda di superficie eccitante il modo protetto. Come
risultato, l’eccitazione è confinata nell’interfaccia, con limitate riflessioni per merito del
confinamento dell’onda e della ridotta velocità della stessa. Tale dispositivo ha ottimi
risultati per il filtraggio (passband di ≈ 1 MHz) e il rallentamento del segnale (velocità
dell’onda di ≈ 1/10).Surface acoustic wave (SAW) devices are versatile and cheap instruments suitable for a
wide range of applications. Such devices exploit piezoelectric materials to transform electric signal into an elastic surface wave, that can be manipulated and filtered. Therefore,
SAW devices are useful for filtering, sensing, actuation, signal control in telecommunications, biomedical and industrial applications, and even in quantum computing. Demand
for SAW with better performance, lower cost and smaller dimensions is increasing in industry. In this thesis, the consolidated idea of SAW is reconsidered, trying to combine
SAWs with topological metamaterials. The long-term aim is to create compact devices,
exploiting the advantages of topologically protected modes. The focus of this thesis is on
the individuation of a geometry suitable for a topologically protected mode. The proposed
SAW device is theoretically based on the Su-Schrieffer-Heeger (SSH) model for topological
insulators. According to SSH a defect within a periodic array of cells is potentially a location for a topologically protected mode, provided that the unit cell has certain dispersion
properties. The real SAW device is composed by unit cells made of two resonators. A
suitable positioning of unit cells creates an interface, materializing a preferential pathway for surface wave exciting the protected mode. As a result, the excitation is confined
within the interface, with reduced reflections due to wave confinement and slow speed.
Such a device have good performances in signal filtering (passband width of ≈ 1 MHz)
and delaying (≈ 1/10 of wave speed)
Ha-Dibbur Ha-Ivri
No full textHebrew Speech, a manual for beginners for the study of Hebrew according to the Natural Method). Author: M. Krinsky. Illustrator: H. Goldberg. Publisher: Ha-Or Publishing. . 146 pp. 254 b/w ills. (+1 color chart) + cover b/w ill. primer.Digital imagedigitize
Author Ha Jin at Kalamazoo College
No full textPhotographer unknown.Author Ha Jin's book "Waiting" was selected for the 2002 Summer Common Reading program at Kalamazoo College. The author visited campus that year as part of the program
Developing A Marketing Recruitment Strategy For International Business
No full textOver the last 20 years, recruiting strategies have changed considerably due to the expansion of technology and the Internet. Human resources are also contemplated as the core competitive factor of businesses. This research is conducted to systematize the theoretical basis related to recruitment marketing. Moreover, at various phases, it employs both qualitative and quantitative research approaches.
In terms of the empirical component, the owner of the corporate case provided qualitative data. In contrast, quantitative data from possible candidates were reviewed. The theoretical portion gives the audiences a fundamental understanding of recruiting and the use of a recruitment marketing strategy. The author researched some surveys and case studies to gather data from both employees and employers.
On the whole, the research findings disclosed the importance of recruitment marketing to international enterprises. Businesses should focus on recruitment marketing to improve recruitment efficiency and reach a bigger pool of potential talents. In the end, the author designated some recommendations for businesses to improve recruitment marketing effectiveness
Color TV PCB automatic testing and alignment -design and testing of SAW filters
No full text학위논문(석사) - 한국과학기술원 : 전기 및 전자공학과 산업전자, 1980.2, [ iii, 95 p. ]Computer aided design programs of the SAW filter which can be applied to the asymmetrical and nonlinear phase filters, is developed using the windowing method. Using the frequency sampling technique, a new design method is studied to obtain the higher stopband attenuation in the stopband. Analysis program, which predicts the actual frequency responses of SAW filters to be fabricated, is developed. Utilizing some recently developed theory and effective computation algorithm, computation time is greatly reduced. Finally, a testing and adjustment method of the SAW filter using microcomputer, is devised and implemented.한국과학기술원 : 전기 및 전자공학과 산업전자
All of Life as Worship, with Theological Librarian, PhD Candidate, and Author Sam Ha
No full textSam Ha, PhD Candidate and Meeter Center for Calvin Studies Curator, recently released his book, A Day of Worship: Adoring God in Every Moment. The book is a pastorally-rich, theologically in-depth exploration of how each moment of life-mundane and special-can be a form of worship before God. Within its first week, it became the 2nd most sold book in Christianity & theology books in Sam’s home country of Korea
Semiometrics: producing a compositional view of influence
No full textHigh-impact academic papers are not necessarily the most cited. For example, Einstein's 'Special Relativity' paper from 1905 received (and continues to receive) fewer citations from other papers than his 'Brownian Motion" paper of the same year, despite the former radically changing the course of an entire scientific discipline to a much greater extent. Similarly, 'impact' metrics using citation count alone are, it is argued, not adequate for determining the scientific influence of papers, authors or small groups of authors. Although valid, they remain controversial when used to determine influence of larger groups or journals. While the term 'impact' has become closely linked to a journal's citation-based Journal Impact Factor score, this thesis uses the term 'influence' to describe the wider effectiveness of research, combining citation and metadata analysis to allow richer calculations to be performed over large-scale document networks. As a result, more qualitative influence ratings can be determined and a broader outlook on scientific disciplines can be produced. These ratings are best applied using an ontology-based data source, allowing more efficient inference than under a traditional RDBMS system, and allowing easier integration between heterogeneous data sources. These metrics, termed 'Semantic Bibliometrics' or 'Semiometrics', can be applied at a variety of levels of granularity, allowing a compositional framework for impact and influence analysis. This thesis describes the process of data preparation, systems architecture, metric value and data integration for such a system, introducing novel approaches at all four stages, thereby creating a working semiometrics system for determining influence at different semantic levels of granularity
Detection of large sequence insertions by a hybrid approach that combine de novo assembly and resequencing of medium-coverage genome sequences
No full textLarge sequence insertion (LSI) is one of the structural variations (SVs) that may cause phenotypic differences in plants. To identify the LSIs using medium-coverage sequencing data of four wild soybean (Glycine soja) genotypes, we designed a hybrid approach combining de novo assembly and read mapping. Total reads and reads with both ends unmapped were independently assembled into “ordinary contigs” and “orphan contigs”, respectively, and subjected to pairwise alignment and stringent filtering. This approach predicted 24 LSIs averaging 2,682 bp in size, with no overlap with SVs detected by Pindel, BreakDancer, or ScanIndel, and they were validated by PCR. Compared with the soybean (Glycine max) reference genome, 20 LSIs were located outside genic regions. One of the four LSIs within a genic region, LSI05, is located in the coding DNA sequence region of a protein kinase superfamily gene (Glyma.08G123500). It caused delayed translation initiation and loss of 24 amino acids in the wild soybean genotype CW12. LSI05 was more frequently observed in 29 G. soja accessions than in 34 G. max accessions. Identified LSIs would be genomic resources harboring novel gene contents for studying SVs and improving crops. Moreover, our cost-efficient approach may be applicable to other plant species.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
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