Miniaturized DGS and EBG structures for decoupling multiple antennas on compact wireless terminals

MIMO (Multiple Input Multiple Output) technology has been presented to significantly increase the wireless channel capacity and reliability without requiring additional radio spectrum or power. In MIMO systems, multiple antennas are mounted at both the transmitter and the receiver. When this technology is employed for a compact wireless terminal, one of the most challenging tasks is to reduce the high mutual coupling between closely placed antenna array elements. The high mutual coupling produces high correlation between antenna elements and affects the channel capacity of MIMO system. The objectives of this thesis are to design practical miniaturized structures to reduce high mutual coupling for small wireless terminals. The research is conducted in the following areas. Initially, a PIFA design and two-element PIFA array are proposed and optimized to operate at 1.9GHz. A pair of two coupled quarter-wavelength linear slits is inserted in a compact ground plane, resulting in significant reduction of the mutual coupling across antenna operating frequency band. In order to take up less space on the ground plane, instead of the linear slits, miniaturized convoluted slits are implemented between the two closely placed PIFAs. Although the convoluted slits have small area and are positioned close to the edges of the ground plane, the miniaturized convoluted slit structures achieve a reduction of mutual coupling between antenna elements and succeed in reducing the effect of the human body (head and hand) to the antennas. In order to further reduce the size of the slits etched on the compact ground plane, a novel double-layer slit-patch EBG structure is proposed. It consists of a two-layer structure including conducting patches and aperture slits placed on either side of a very thin dielectric layer. They are placed in very close proximity to each other (55μm). A two-element printed CPW-fed monopole array operating around 2.46GHz and a two-element UWB planar monopole array operating from 3GHz to 6GHz have been employed to investigate the proposed slit-patch EBG structures. The optimized double-layer slit-patch EBG structure yields a significant reduction of the mutual coupling and produces the maximum miniaturization of antenna array. Another novel convoluted slit-patch EBG structure has been presented to reduce the mutual coupling between two PIFAs operating at 1.9GHz. These results demonstrate that the slit-patch EBG structure is a feasible technology to reduce the mutual coupling between multiple antennas for compact wireless terminals

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Einfluss der Verarbeitungstechnologie und Werkstoffzusammensetzung auf die Struktur-Eigenschafts-Beziehungen von thermoplastischen Nanoverbundwerkstoffen

Die Einarbeitung von nanoskaligen Füllstoffen zur Steigerung von polymeren Eigenschaftsprofilen ist sehr viel versprechend und stößt daher heutzutage sowohl in der Forschung als auch in der Industrie auf großes Interesse. Bedingt durch ausgeprägte Oberflächen und hohe Anziehungskräfte, liegen Nanopartikel allerdings nicht singulär sondern als Partikelanhäufungen, so genannten Agglomeraten oder Aggregaten, vor. Zur Erzielung der gewünschten Materialverbesserungen gilt es, diese aufzuspalten und homogen in der polymeren Matrix zu verteilen. Bei thermoplastischen Kunststoffen ist die gleichläufige Doppelschneckenextrusion eines der gängigsten Verfahren zur Einarbeitung von Additiven und Füllstoffen. Aus diesem Grund war es Ziel dieser Arbeit, mittels dieses Verfahrens verbesserte Verbundwerkstoffe mit Polyamid 66- und Polyetheretherketon-Matrix, durch Einarbeitung von nanoskaligem Titandioxid (15 und 300 nm), zu generieren. In einem ersten Schritt wurden die verfahrenstechnischen Parameter, wie Drehzahl und Durchsatz, sowie die Prozessführung und damit deren Einfluss auf die Materialeigenschaften beleuchtet. Der spezifische Energieeintrag ist ausschlaggebend zur Deagglomeration der Nanopartikel. Dieser zeigte leichte Abhängigkeiten von der Drehzahl und dem Durchsatz und verursachte bei der Einarbeitung der Partikel keine wesentlichen Unterschiede in der Aufspaltung der Partikel sowie gar keine in den resultierenden mechanischen Eigenschaften. Die Prozessführung wurde unterteilt in Mehrfach- und Einfachextrusion. Die Herstellung eines hochgefüllten Masterbatches, dessen mehrfaches Extrudieren und anschließendes Verdünnen, führte zu einer sehr guten Deagglomeration und stark verbesserten Materialeigenschaften. Mittels Simulation des Extrusionsprozesses konnte festgestellt werden, dass das Vorhandensein von ungeschmolzenem Granulat in der Verfahrenszone zu einer Schmelze/Nanopartikel/ Feststoffreibung führt, die die Ursache für eine sehr gute Aufspaltung der Partikel zu sein scheint. Durch Modifikation des Extrusionsprozesses erreichte die Einfachextrusion annähernd den Grad an Deagglomeration bei Mehrfachextrusion, wobei die Materialien bei letzterem Verfahren die besten Eigenschaftsprofile aufwiesen. In einem zweiten Schritt wurde ein Vergleich der Einflüsse von unterschiedlichen Partikelgrößen und –gehalten auf die polymeren Matrizes vollzogen. Die 15 nm Partikel zeigten signifikant bessere mechanische Ergebnisse auf als die 300 nm Partikel, und die Wirkungsweise des 15 nm Partikels auf Polyetheretherketon war stärker als auf Polyamid 66. Es konnten Steigerungen in Steifigkeit, Festigkeit und Zähigkeit erzielt werden. Rasterelektronenmikroskopische Aufnahmen bestätigten diese Ergebnisse. Eine Berechnung der Plan-Selbstkosten von einem Kilogramm PEEK-Nanoverbundwerkstoff im Vergleich zu einem Kilogramm unverstärktem PEEK verdeutlichte, dass ein Material kreiert wurde, welches deutlich verbesserte Eigenschaften bei gleichem Preis aufweist. Zusammenfassend konnte in dieser Arbeit ein tieferes Verständnis des Extrusionsvorganges zur Herstellung von kostengünstigen und verbesserten Thermoplasten durch das Einbringen von Nanopartikeln gewonnen werden

Data_Sheet_1_A preliminary study on the online processing of anticipatory tonal coarticulation – Evidence from eye movements.docx

While the f0 realization of lexical tones vary extensively in contexts, little has been known on how listeners process the variation in lexical tones due to contextual effects such as tonal coarticulation in spoken word recognition. This study thus aims to fill the knowledge gap in tone perception with evidence from two types of anticipatory tonal coarticulation effects in Tianjin Mandarin, i.e., the slope raising effect due to a following low-falling tone and the overall-height raising effect due to a following low-dipping tone. An eye-tracking experiment with the Visual World Paradigm was carried out to compare participants’ eye movements when they heard targets in three types of anticipatory raising conditions, i.e., the Slope Raising condition, the Overall-height Raising condition, as well as the No Raising condition (the baseline). The eye movement results showed significant differences in the proportion of looks to target between the Slope Raising condition versus the other two conditions, whereas the Overall-height Raising condition did not differ significantly from the No Raising condition. The findings thus suggest the facilitatory effect of tonal coarticulation cues in the anticipation of the upcoming tones, but listeners in this study seemed to be only sensitive to the raising in the f0 slope rather than the overall raising in the f0 height.</p

DataSheet1_The regulation of adipocyte growth in white adipose tissue.PDF

Adipocytes can increase in volume up to a thousand-fold, storing excess calories as triacylglycerol in large lipid droplets. The dramatic morphological changes required of adipocytes demands extensive cytoskeletal remodeling, including lipid droplet and plasma membrane expansion. Cell growth-related signalling pathways are activated, stimulating the production of sufficient amino acids, functional lipids and nucleotides to meet the increasing cellular needs of lipid storage, metabolic activity and adipokine secretion. Continued expansion gives rise to enlarged (hypertrophic) adipocytes. This can result in a failure to maintain growth-related homeostasis and an inability to cope with excess nutrition or respond to stimuli efficiently, ultimately leading to metabolic dysfunction. We summarize recent studies which investigate the functional and cellular structure remodeling of hypertrophic adipocytes. How adipocytes adapt to an enlarged cell size and how this relates to cellular dysfunction are discussed. Understanding the healthy and pathological processes involved in adipocyte hypertrophy may shed light on new strategies for promoting healthy adipose tissue expansion.</p

Construction and analysis for differentially expressed long non-coding RNAs and MicroRNAs mediated competing endogenous RNA network in colon cancer

<div><p>Long non-coding RNA (lncRNA) has been confirmed to act as a key regulatory molecule in different types of cancers and play a significant role in tumors initiation and progression. LncRNA can be as acompeting endogenous RNA(ceRNA) to regulate the expression of targeted genes by sponging miRNA. In the present study, we explore the functional roles and regulatory mechanisms of lncRNAs as ceRNAs in colon cancer and their potential implications for prognosis.The lncRNAs, miRNAs and mRNAs expression profiles of 341 colon cancer tissues and 27 non-tumor colon tissues were downloaded from The Cancer Genome Atlas (TCGA) database. Differential expression of RNAs was identified using the “DESeq” bioconductor package in R. PPI network of differentially expressed genes was constructed using the STRING database. Survival analysis was estimated based on Kaplan-Meier curve analysis. We used KOBAS 3.0 to analyze the KEGG pathway of DEGs. The dysregulated lncRNA-associated ceRNA network was constructed in colon cancer based on bioinformatics generated from miRanda, PicTar, TargetScan, miRDB and miRcode. A total of 791 DElncRNAs and 200 DEmiRNAs were identified in colon cancer compared with matched normal tissues with thresholds of |log2foldChange (FC)| >3.0and adjusted <i>P</i> value<0.05.Twenty DElncRNAs were identified, may be related to tumorigenesis and/or progression of colon cancer. Nine out of 20 dysregulated lncRNA were found to be significantly associated with overall survival (<i>P</i> value<0.05). Finally, we successfully constructed colon cancer-associated ceRNA network, including 9 colon cancer-specific lncRNAs, 13 miRNAS and 70 mRNAs. In conclusion, our study will contribute to improve the understanding of ceRNA network regulatory mechanisms in colon cancer. These identified novel lncRNAs can be as candidate prognostic biomarkers or potential therapeutic targets.</p></div

Density Functional Theory Study of the Mechanism of the Rhodium(I)-Catalyzed Conjugated Diene Assisted Allylic C–H Bond Activation and Addition to Alkenes Using Ene-2-dienes As Substrates

Recently we reported the first conjugated diene assisted, rhodium-catalyzed allylic C–H bond activation and addition to alkenes to synthesize multifunctional tetrahydropyrroles, tetrahydrofurans, and cyclopentanes from ene-2-diene substrates, with good to excellent diastereoselectivities. Here we report a DFT study of the mechanism of this reaction, aiming to obtain a detailed potential energy surface, to understand factors determining its stereochemistry, and to determine why conjugated diene is very critical for the success of this reaction. DFT calculations unveiled that the catalytic cycle of this reaction involves a sequence of substrate–catalyst complex formation, allylic C–H activation, alkene insertion into the Rh–H bond, and di-π-allyl-assisted C­(sp³)–Rh–C­(sp³) reductive elimination, among which the C–H activation and alkene insertion steps are reversible. The main reason for the formation of the cis-divinyl product is that the irreversible reductive elimination transition state from the bis-allylic Rh complex favors a cis 5/5 bicyclic conformation to reduce the ring strain. Moreover, formation of the cis-divinyl product is also assisted by the alkene coordination to the Rh center in the reductive elimination transition state. DFT insights revealed that the conjugated diene, which is very critical for the target reaction, disfavors the double-bond isomerization and facilitates the reductive elimination for the bis-allylic Rh complex, causing the C–H activation and alkene insertion to occur. The computational results showed that the bridgehead double-bond distortion, as suggested by the Bredt’s rule, is responsible for not generating the type II [4+2] cycloadducts from ene-2-dienes

DElncRNAs-related ceRNA network in colon cancer.

<p>The red represent increased level of expression, while the green represent decreased level of expression. Round rectangle represent lncRNAs; hexagon represent miRNAs; ellipse represent protein-coding genes; black edges indicate lncRNA-miRNA-mRNA interactions.</p

Nine DElncRNAs interact with the 13 DEmiRNAs retrieving miRcode database.

<p>Nine DElncRNAs interact with the 13 DEmiRNAs retrieving miRcode database.</p

Eighteen colon cancer specific miRNAs in ceRNA network.

<p>Eighteen colon cancer specific miRNAs in ceRNA network.</p