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An Annual Ring Antenna for UWB Communications
IEEE Antennas and Wireless Propagation Letters, 2006An ultrawideband (UWB) annual ring antenna is presented in this letter. The annual ring antenna has a return loss better than 10 dB from 2.8 to 12.3 GHz. It has an average gain of 2.93 dBi and has a maximum gain of 5 dBi at 7 GHz. The antenna radiation patterns are stable within its operation band.
Y.-j. Ren, K. Chang
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Climatic response of annual tree-rings
SPIE Proceedings, 2014Extensive literature devoted to investigations into the influence of environmental conditions on the plant respiration and respiration rate. It is generally accepted that the respired CO2 generated in a stem completely diffuses into the atmosphere. Results obtained from explorations into the CO2 content in disc tree rings by the method proposed in this
Boris G. Ageev +3 more
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Annual Bird Ringing Totals and Population Fluctuations
Oikos, 1978Ringing of migrant birds has taken place at Ottenby, Oland, southeast Sweden since 1947. The effect of the winter weather in northwestern Europe on the wren Troglodytes troglodytes, of precipitation in the Sahel zone on the common whitethroat Sylvia communis and of the use of alkyl mercury compounds in Swedish agriculture on the yellowhammer Emberiza ...
Christian Hjort +2 more
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Planar magnetostatic wave resonator with annual-ring slot
IEEE 1991 Ultrasonics Symposium, 2002A novel type of resonator using magnetostatic forward volume waves (MSFVWs) with an annual-ring slot is presented, where the annual-ring slot formed on an yttrium iron garnet (YIG) film by a photolithography technique plays a role in confining the energy of magnetostatic waves.
N. Guan, K. Yashiro, S. Ohkawa
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A simple model for density of annual rings
Wood Science and Technology, 1995A simple model for density distribution within an annual ring is proposed. The model originates from the concept that a tree has two growing modes ''early'' and ''late'' wood mode respectively and ...
K. Pernest�l, B. Jonsson, B. Larsson
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Broadband Dual-frequency CPW-fed Annual-ring Antenna
2006 IEEE Antennas and Propagation Society International Symposium, 2006A new broadband annual-ring antenna fed by CPW (coplanar waveguide) is developed for mobile communication applications. The antenna adopts a single-layer double-side configuration. Two annual rings are used to activate the dual operating frequencies.
null Yu-Jiun Ren, null Kai Chang
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Radiocarbon Measurements and Annual Rings in Cave Formations
Nature, 1960THE radiocarbon method has been used to test the hypothesis that the prominent rings found in certain calcite deposits of Moaning Cave in California represent annual growth variations. Carbon-14 an alyses were made on two samples taken, from a presumably active section of travertine covering a human femur (Fig. 1). When discovered in 1951, the specimen
WALLACE S. BROECKER +2 more
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Stiffening phenomena in annual rings of coniferous wood
Wood Science and Technology, 1984The structure of coniferous wood is characterized by pronounced differences in density between earlywood and latewood. This could result in disadvantages in wood strength especially against bending. A summary of the observations in this paper leads to the following hypothesis: Coniferous trees meet this danger by forming numerous stiffenings especially
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Annual growth rings in the mangrove Laguncularia racemosa (Combretaceae)
Trees, 2008Stem discs from trees of known age were used to determine the periodic nature of the growth rings formed in Laguncularia racemosa and to describe the anatomical features of these rings. The growth rings were scarcely distinct on microscopic examination, but they were well distinguishable macroscopically, with alternating light brown and dark brown ...
Gustavo Calderucio Duque Estrada +3 more
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Growth Rings: Annual Periodicity in Two Gorgonian Corals
Ecology, 1974Comparison of the number of growth rings present in the skeletons of colonies of two gorgonian corals, Muricea californica and M. fruticosa, with estimates of their age based on observed growth rates indicates that the periodicity of ring formation is annual. Data from two other methods used to determine periodicity support this conclusion. The results
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