An Ising Model for Metal-Organic Frameworks

We present a three-dimensional Ising model where lines of equal spins are frozen in such that they form an ordered framework structure. The frame spins impose an external field on the rest of the spins (active spins). We demonstrate that this "porous Ising model" can be seen as a minimal model for condensation transitions of gas molecules in metal-organic frameworks. Using Monte Carlo simulation techniques, we compare the phase behavior of a porous Ising model with that of a particle-based model for the condensation of methane (CH$_4$) in the isoreticular metal-organic framework IRMOF-16. For both models, we find a line of first-order phase transitions that end in a critical point. We show that the critical behavior in both cases belongs to the 3D Ising universality class, in contrast to other phase transitions in confinement such as capillary condensation.Comment: 11 pages, 9 figure

The Anglet: An E/H-plane Bent, 90-Degree Twisted, TE101/TM110-Mode Singlet Building Block

In this work, a subclass of the singlet building block is defined. Termed the anglet, a waveguide cavity-based structure is demonstrated that combines a bend, a 90-degree polarization rotation, and produces one pole and one transmission zero. The anglet is defined due to its unique ability to be viewed as either a TE101-mode singlet or a TM110-mode singlet based on the users coordinate point of view together with the requirements for the bend direction and polarization rotation. Two types of anglets are demonstrated by simulation and a third-order filter is demonstrated for the incorporation of an anglet in a practical design. Emphasis on its unique capabilities are highlighted due to its nature as a fundamental-mode resonator with evanescent bypass coupling. Furthermore, an accurate approximation for the source-load coupling is described and a prototype filter is fabricated and measured in order to validate the concept

W‐band TE102‐mode filter with doubly loaded E‐plane and H‐plane irises

In this correspondence, high-precision computer numerical control milling is utilised to demonstrate a doubly loaded iris, cross-coupled waveguide bandpass filter for inline operation within the W-band. This sixth-order filter is designed in a stacked H-plane configuration and utilises both E-plane and H-plane doubly loaded irises to maintain the flow of a TE102-mode electromagnetic field. In this configuration, a high rejection level is maintained outside of the passband while a good unloaded quality factor is obtained through the support of larger resonator dimensions. The filter is designed for approximately 2% fractional bandwidth centred at 97.5 GHz and has been fabricated as three brass components. Measurements of the filter agree very well with the simulated results and demonstrate a spurious-free design over the full W-band

Miniaturized Dual-Band Dual-Mode TM-Mode Dielectric Filter in Planar Configuration

This paper reports a new class of compact inline dual-band bandpass filters using TM-mode dielectric resonators in planar configuration. Thanks to the employment of the dielectric-loaded TM-mode waveguide configuration and the dual-mode TM120 and TM210 resonances, substantial size miniaturization and volume saving (>70%) can be obtained in comparison with conventional waveguide technology. Additionally, the planar topology of the presented concept offers highly desirable advantages for industry and mass production including the ease of manufacturing, assembly, and tuning. Furthermore, the resonating doublets and the nonresonating TM110 mode are effectively utilized to introduce and control both inter-band and outer-band transmission zeros, advantageously increasing the isolation between the two passbands and enhancing the outer-band rejection regions. The general design procedure of the proposed filter is discussed in detail. A three-pole C-band dual-band dual-mode TM-mode dielectric filter is designed, implemented, and measured to validate the proposed configuration

Very Compact Diplexer Based on Dual-Mode Dielectric TM-Mode Resonators

A very compact in-line C-band diplexer is reported in this letter based on dual-mode dielectric TM-mode resonators in planar coupling configuration. In addition to the advantages of substantial volume-saving and easy assembly, the proposed diplexer features high-quality factor, enhanced spurious performance, high-power handling, and efficient tuning process with independent control of each passband. For verification purposes, a C-band diplexer is designed, implemented, and tested. The final assembled diplexer unit has a compact overall volume of 43 × 40 × 15.9 mm 3 . It operates at 4.73 and 5.03 GHz with the same bandwidth of 24 MHz, an insertion loss better than 0.9 dB, and a return loss higher than 21 dB. In addition, a high-power breakdown analysis shows that the introduced diplexer can handle high levels of input power up to 5200 W

Coinitial sets and fixed points in partially ordered sets

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45432/1/12_2005_Article_BF01191777.pd

Grußwort für den AStA

Der vorliegende Band dokumentiert Reden, die zur Amtseinführung von Prof. Dr.-Ing. habil. Monika Auweter-Kurtz als Präsidentin der Universität Hamburg am 1. Februar 2007 gehalten wurden.This volume documents speeches given at the inauguration of Prof. Dr. -Ing. habil. Monika Auweter-Kurtz as President of the University of Hamburg on 1 February 200