Novel and compact open‐ended CRLH‐TL notch filter

A novel and very small metamaterial notch filter below 900 MHz is proposed in this paper. In the UHF band, compared to the size of the open‐ended quarter‐wavelength stub that is, 0.25 λ_g (42 mm), the length of the proposed filter is 0.07 λ_g (12 mm) approximately five times smaller. The notch filter is realized by a very short 90°‐phase shifter of the CRLH structure with one‐end open‐terminated. The design method is explained theoretically, while the circuit and geometry are simulated and validated through EM simulations and fabrication. The measured results show a high degree of agreement with the simulated results. The results illustrate the notch created at 900 MHz by the filter to avoid the conflict with Z‐wave communication, UHF RFID tag and uplink of GSM‐E. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:247–253, 2016.     

DOE-Based Extraction of CMP, Active and Via Fill Impact on Capacitances

Chemical-mechanical polishing (CMP), active and via fills have become indispensable aspects of semiconductor manufacturing. CMP fills are used to reduce metal thickness variations due to chemical-mechanical polishing. Via fills are used to improve neighboring via printability and reliability of low-k and ultra low-k dielectrics. Active region fills are used for STI CMP uniformity and stress optimization. Although modern parasitic extraction tools accurately handle grounded fills and regular interconnects, such tools use only rough approximations to assess the capacitance impact of floating fills, such as assuming that floating fills are grounded or that each fill is merged with neighboring ones. To reduce such inaccuracies, we provide a design of experiments (DOE) which complements what is possible with existing extraction tools. Through the proposed DOE set, a design or mask house can generate normalized fill tables to correct for the inaccuracies of existing extraction tools when floating fills are present. Golden interconnect capacitance values can be updated using these normalized fill tables. Our proposed DOE enables extensive analyses of fill impacts on coupling capacitances. We show through 3-D field solver simulations that the assumptions used in extractors result in significant inaccuracies. We present analyses of fill impacts for an example technology and also provide analyses using the normalized fill tables to be used in the extraction flow for three different standard fill algorithms. We also extend our analyses and methodology to via fills and active region fills, which have more recently been introduced into semiconductor design-manufacturing methodologies and for which sufficient understanding is still lacking.     

Mothers with serious mental illness: When symptoms decline does parenting improve?

Serious mental illnesses (SMI) and problems with parenting are associated, but the link between change in psychiatric symptoms and change in parenting over time has not been examined. Three hypotheses were tested. Hypothesis 1: As symptoms decline, parenting stress will decline and parenting nurturance will improve. Hypothesis 2: High prior levels of symptoms have a continuing impact on parenting over time, persisting even when symptoms remit. Hypothesis 3: Both symptoms and parenting are influenced by contextual factors; taking these into account diminishes the association between them. With the use of latent growth curve modeling and an economically and racially diverse sample of mothers with SMI (N = 294), evidence supporting Hypothesis 1 was found, but there was no support for Hypothesis 2. For Hypothesis 3, contextual factors predicted both symptoms and parenting; accounting for context diminished the association between symptoms and parenting stress, but context did not completely explain the association between symptoms and parenting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Achieving chiral resolution in self-assembled supramolecular structures through kinetic pathways

Chiral phase transitions were studied in a self-assembled 2,6-dibromoanthraquinones supramolecular system prepared on Au(111) using scanning tunneling microscopy. As the molecules were deposited at about 150?K, they formed heterochiral chevron structures (a racemate) consisting of two alternating prochiral molecular rows. When the as-deposited sample was warmed to 300?K followed by cooling to 80?K, phase-separated homochiral structures (a conglomerate), as well as the chevron structures, were observed. We propose molecular models for the structures that are in good agreement with ab?initio studies and can be explained by hydrogen bonds and halogen bonds. We found that heterochiral chevron structures were more stable than homochiral structures due to two additional [Formula: see text] halogen bonds per molecule. We considered kinetic pathways for the phase transitions that were made possible via a disordered liquid phase entropically stabilized at 300?K. We show how chiral resolution can be achieved by exploiting kinetic paths allowed in supramolecular systems.     

Metal-supported high crystalline Bi₂Se₃ quintuple layers

Atomically flat thin films of Bi(2)Se(3) were grown on Au(111) metal substrate using molecular beam epitaxy. Hexagonal atomic structures and quintuple layer steps were observed at the surfaces of grown films using scanning tunneling microscopy. Multiple sharp peaks from (003) family layers were characterized by x-ray diffraction measurements. The atomic stoichiometry of Bi and Se was considered using x-ray photoemission spectroscopy. Moiré patterns were obtained at the surfaces of one quintuple layer films due to lattice mismatch between Bi(2)Se(3) and Au. Our experiments suggest that Au is a reasonable material for electrodes in Bi(2)Se(3) devices.     

Adsorption of Helium and Other Gases to Carbon Nanotubes and Nanotube Bundles

There is considerable interest in the adsorption of helium and other gases to unconventional substrates. Carbon nanotubes and bundles of such tubes provide a relatively unique and interesting substrate opportunity. We describe recent experimental and theoretical work from a number of groups that sheds light on the behavior of various gases adsorbed to these unusual substrates.