Polarization conversion from a thin cavity array in the microwave regime

Open Access journalLinearly polarized microwave radiation is shown to have its plane of polarization converted to the orthogonal state upon reflection from an ultrathin (λ/25) cavity array. The structure benefits from an uncomplicated design consisting of a metallic grating closely separated from a ground plane by a dielectric spacer. A single set of periodically spaced slits (monograting) exhibits polarization conversion when the normally incident electric field is aligned at 45° to the slits. Two orthogonal sets of slits (bigrating) allows this narrow-band effect to be broadened when the two orthogonal resonances are separated in frequency. We optimise the design and experimentally demonstrate near loss-less polarization conversion (95% of the incident intensity) across a 3.1 GHz frequency band. Finally, we study the dependence of the structure's performance on incident angle and slit width.DSTLEngineering and Physical Sciences Research Council (EPSRC

The effect of rotational disorder on the microwave transmission of checkerboard metal square arrays

Published onlineJournal ArticleResearch Support, Non-U.S. Gov'tThe effect of rotational disorder on the microwave transmission through thin metallic checkerboard arrays has been experimentally studied. Broad resonant features below the onset of diffraction, attributed to electromagnetic radiation coupling through the structure via the evanescent fields of bound surface waves, are found to be strongly dependent on the electrical connectivity of the surface. By applying rotational disorder to the elements comprising the arrays, with the lattice constant and element size unchanged, the electrical connectivity of the structure can be controlled whilst maintaining periodicity. The results show that rotational disorder can significantly affect transmission only when it changes the structure's connectivity. When the initial structure is just above the connectivity threshold (where the metallic occupancy is 50%), increasing disorder causes the resonant features in transmission to invert as the structure switches from a predominantly connected array to a disconnected array. When approximately half of the connections are broken, the resonant features are suppressed, with scattering loss shown to dramatically increase to as much as 40% of the incident power over a broad frequency range. The result is a thin, highly effective scatterer of microwaves.The authors acknowledge the financial support of DSTL. APH and JRS also acknowledge the support of EPSRC through the QUEST programme grant

Prospectus, July 11, 1984

DREAM OF A LIFETIME REALIZED EISNER CHANGES HANDS: BECOMES DIANA FOODS; 98 percent of area residents are within 4 blocks of MTD\u27s economical-efficient-comfortable and friendly transportation; News Digest; Husbands, wives benefit from sharing the work; Did You Know...; Lake of the Woods features \u27Music in Park\u27; Philosophy club proposed; The unsung heros of Parkland; The Garden Spot; Entire student body not at risk; Recycling Center at fair; Annual 4th of July parade provides delights for all; Creative Corner...especially for you; Angie; Rites of Passage; Scared Love; Rejoice the Poet; Odyssey; Stallone\u27s versatility is obvious in Rhinestone performance Dolly and Sly are dynamite; Dr. Who and Star Trek convention; Grace Jones a riot in film debut; Krantz creates magic; Study shows coaches consign blacks to certain positions; ERES mid-stae tour planned; Sports Digest; \u27Everyone has a dream\u27; Tad Powers works on hishttps://spark.parkland.edu/prospectus_1984/1017/thumbnail.jp

Soybean Cyst Nematode Reduces Soybean Yield Without Causing Obvious Aboveground Symptoms

Field experiments were conducted at locations in northern and southern Illinois, central Iowa, and central Missouri from 1997 to 1999 to investigate the effects of Heterodera glycines on soybean growth, development, and yield. A wide range of infestation levels was present at all locations. Two locally adapted cultivars, one resistant to H. glycines, were grown at each location. Cultivars were planted in alternating four-row strips with 76 cm between rows. For each cultivar, 20 1-m-long single-row plots were sampled every 2 weeks starting 4 weeks after planting. Infection by H. glycines reduced plant height and leaf and stem weight on the resistant cultivars in the first 12 weeks after planting, and delayed pod and seed development 12 to 14 weeks after planting. Biomass accumulation was not reduced on the susceptible cultivars until 10 weeks after planting; reduction in pod and seed development occurred throughout the reproductive stages. Susceptible cultivars produced significantly lower yields than resistant cultivars, but the yield reductions were not accompanied by visually detectable symptoms

Radiatively Induced Neutrino Masses and Large Higgs-Neutrino Couplings in the Standard Model with Majorana Fields

The Higgs sector of the Standard Model with one right-handed neutrino per family is systematically analyzed. In a model with intergenerational independent mixings between families, we can account for very light neutrinos acquiring Majorana masses radiatively at the first electroweak loop level. We also find that in such a scenario the Higgs coupling to the light-heavy neutrinos and to the heavy-heavy ones may be remarkably enhanced with significant implications for the production of these heavy neutrinos at high energy colliders.Comment: Making the text of an old paper electronically availabl

Prospectus, May 2, 1984

SUPPORT YOUR COLLEGE! VOTE FOR STUDENT GOVERNMENT OFFICERS; News Digest; Students protest CIA campus recruitment; PC Happenings; Humanities Awards Program Summer Research; Student Government candidate platforms; Fearing suits, many colleges move to control students closely; Creative Corner...Especially for you!!; Energy from the Garden; Elf; Bums; Rites of Passage; Angie; To Those Who Have Loved and Lost...; Nuclear Weapons Freeze; Finney\u27s Famous Fanwich, on Rye; Settlement on the Sangamon; Freedom summer campaign seeks 5,000 students; Campaign for a Humane Center; Non-Event kick-off; Did you know...; Classifieds; Parkland\u27s Fine Art students\u27 work exhibited in Art Gallery; Philosophy discussion group--know yourself and your world; Top AHT students receive awards; March of Dimes plans events; Two artists exhibit work; Campus springtime; \u27The Hollywood Hall of Shame\u27 -- behind the scenes dirt; \u27Android\u27 high quality with low budget; WILL airs high drama; Sports Digest; Midwest Open successful; Parkland\u27s women\u27s basketball team finishes third offensively; Scholarships should help Parkland\u27s athletics; Cobras split with Vincennes with two from Olneyhttps://spark.parkland.edu/prospectus_1984/1022/thumbnail.jp

Ideal Weyl points and helicoid surface states in artificial photonic crystal structures (article)

The dataset associated with this article is located in ORE at: http://hdl.handle.net/10871/30744This is the author accepted manuscript. The final version is available from AAAS via the DOI in this record.Weyl points are the crossing points of linearly dispersing energy bands in the Brillouin zone of three-dimensional crystals. Weyl points provide the opportunity to explore a variety of intriguing phenomena such as topologically protected surface states and chiral anomalies. However the lack of an ideal Weyl system poses a serious limitation to the further development of Weyl physics and potential applications. Here, by experimentally characterizing a microwave photonic crystal comprised of a three dimensional array of saddle-shaped metallic coils, we observe ideal Weyl points which are related to each other through symmetry operations. Topological surface states exhibiting helicoidal structure in the energy-momentum space have also been demonstrated, which serve as a direct manifestation of the chiral nature of the Weyl points.This work was financially supported by ERC Consolidator Grant (Topological) and Leverhulme Trust (RPG-2012-674). S. Z. acknowledges support from the Royal Society and Wolfson Foundation. B. Y. acknowledges support from China Scholarship Council (201306110041). Y. X. acknowledges support from the National Natural Science Foundation of China (Grant No. 61490713). L. E. B. and A. P. H. acknowledge financial support from EPSRC of the United Kingdom (Grant No. EP/L015331/1). C.F. was supported by the National Key Research and Development Program of China under grant No. 2016YFA0302400 and by NSFC under grant No. 11674370. L.L. was supported by the National key R&D Program of China under Grant No. 2017YFA0303800, 2016YFA0302400 and by NSFC under Project No. 11721404

Prospectus, April 24, 1985

https://spark.parkland.edu/prospectus_1985/1011/thumbnail.jp

Challenges and opportunities for ex-offender support through community nursing

This study was a qualitative case study underpinned by “The Silences Framework” aimed at mapping the ex-offender health pathway towards identifying “touch points” in the community for the delivery of a nurse-led intervention. Participants meeting the study inclusion criteria were quantitatively ranked based on poor health. Participants scoring the lowest and endorsing their ranking through a confirmation of a health condition were selected as cases and interviewed over 6 months. Individuals in the professional networks of offenders contextualized emergent themes. The study indicated that pre-release, offenders were not prepared in prison for the continuity in access to healthcare in the community. On release, reintegration preparation did not routinely enquire whether offenders were still registered with a general practitioner or had the agency to register self in the community. Participants identified the site of post-release supervision as the “touch point” where a nurse-led intervention could be delivere