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Circular monopole printed antenna can be designed to cover an ultra wide bandwidth (UWB) of 4:1 ratio with large gain variation over the band. Electromagnetic band gap (EBG) structures/surfaces are used to enhance antenna radiation by generating coherent radiation that adds to the antenna pattern to produce higher gain. A conventional EBG surface has a narrow-band, centered at the resonance frequency that is a function of its dimensions. Stacked EBG structures, on the other hand, can be designed to cover very wide bands that match the operating bandwidths of the UWB antenna. This paper presents the enhanced performance of a UWB circular monopole antenna, achieved through the use of a 3-layer stacked EBG structure. Reflection phase performance of the EBG structure is shown to cover the wideband, and results in higher gain for the monopole over most of the band. The results are compared with a Vivaldi antenna operating at the same wideband to show the higher gain of the lower-profile EBG-enhanced printed circular monopole.

A circular monopole antenna fed with a coplanar waveguide is designed as an ultra-wideband (UWB) antenna for ground-penetrating radar. The performance of the antenna is enhanced by adding an electromagnetic band gap (EBG) surface on one side and a monopole director on the other side. The EBG surface can be a single-resonance structure or dual or multi-resonance structure for wider bandwidth. The enhanced design shows higher and flatter gain across the wideband, with different levels of improvements, depending on the choice of the additional layers, which also impacts the overall profile of the antenna. Simulation results of a number of designs are presented, along with measurement results of one design. Comparison of measured and simulated results is presented and shows good agreement. The target frequency band for the design is 0.7 3.0 GHz.

This paper presents a way in which a broadband EBG structure can be formed by stacking uniform EBG (electromagnetic band gap) structures. The design is validated by using it with a broadband monopole antenna. The paper shows the applications of stacked EBG structure. The performance of the antenna with the stacked EBG is compared with that of a uniform EBG.

In this study, hydrogels consisted of polyvinyl alcohol, propylene glycol and β-glucan were developed by radiation technique for wound dressing. The prepared hydrogels were characterized by examining of physical properties such as gel fraction and absorption ratio. The gel fraction and absorption ratio were dependent on the crosslinking density. On observing the wound healing of rat skin, the resulting hydrogels accelerated the wound healing comparing to cotton gauze. Therefore, the PVA/propylene glycol/β-glucan blended hydrogels can greatly accelerate the healing without causing irritation., {"references":["H. J. Gwon, Y. M. Lim, Y. C. Nho, J. W. Shim, I. K. Kwon, H. N. Chang,\nand S. E. Kim, \"New route for synthesizing poly(ethylene glycol)-acrylic Acid hydrogels using ╬│-irradiation for drug delivery carriers\", Biotech.\nBioproc. Eng., vol. 15, pp. 392-399, 2010.","N. A. Peppas and E. W. Merrill, \"Differential scanning calorimetry of\ncrystallized PVA hydrogels\", J. Appl. Polym. Sci., vol. 20, no. 6, pp.\n1457−1465, 1976.","G. D. Winter, \"Formation of the scab and the rate of epithelization of\nsuperficial wounds in the skin of the young domestic pig\". Nature, vol.\n193, pp. 293-294, 1962.","H. J. Gwon, Y. M. Lim, Y. C. Nho, and S. H. Baik, \"Humectants effect on\naqueous fluids absorption of ╬│-irradiated PVA hydrogel followed by\nfreeze thawing\", Radiat. Phys. Chem., vol. 79, pp. 650-653, 2010.","J. M. Rosiak, \"Radiation formation of hydrogels for drug delivery\", J.\nControl. Release, vol. 31, pp. 9−19, 1994.","C. M. Hassan, J. E. Stewart, and N. A. Peppas, \"Diffusional\ncharacteristics of freeze/thawed PVA hydrogels: applications to protein\ncontrolled release from multilaminate devices,\" Europ. J. Pharm.\nBiopharm., vol. 49, pp. 161−166, 2000.","H. Matsuyama, M. Teramoto, and H. Urano, \"Analysis of solute diffusion\nin poly(vinyl alcohol) hydrogel membrane\", J. Membrane Sci., vol. 126,\npp. 151−160, 1997.","K. Burczak, T. Fujisato, M. Hatada, and Y. Ikada, \"Protein permeation\nthrough poly(vinyl alcohol) hydrogels membranes\", Biomaterials, vol. 15,\nno. 3, pp. 231−238, 1994.","A. Hoelgaarda and B. Mollgaarda, \"Dermal drug delivery: Improvement\nby choice of vehicle or drug derivative\", J. Control. Release, vol. 2, pp.\n111-120, 1985.\n[10] J. M. Rosiak, \"Radiation formation of hydrogels for drug delivery\", J.\nControl. Release, vol. 31, pp. 9−19, 1994.\n[11] A. T. Borchers, C. L. Keen, and M. E. Gershwin, \"Mushrooms, tumors,\nand immunity: An update\", Exp. Biol. Med. Vol. 229, pp. 393−406, 2004.\n[12] S. B. Lee, H. W. Jeon, Y. W. Lee, Y. M. Lee, K. W. Song, M. H. Park, Y.\nS. Nam, and H. C. Ahn, \"Bio-artificial skin composed of gelatin and (1\nÔåÆ 3), (1ÔåÆ 6)-beta-glucan\", Biomaterials, vol. 24, no. 14, pp. 2503-2511,2003.\n[13] J. M. Rosiak and P. Ulanski, \"Synthesis of hydrogels by irradiation of\npolymers in aqueous solution\", Radiat. Phys. Chem., vol. 55, pp.\n139−151, 1999.\n[14] Y. Xiaomin, L. Qi, C. Xiliang, and Z. Zhiyong, \"Investigation on the\nformation mechanisms of hydrogels made by combination of ╬│-ray\nirradiation and freeze-thawing\", J. Appl. Polym. Sci., vol. 108, pp. 1365-1372, 2008."]}

As part of a continuing effort to improve antenna performance using metamaterials, the U.S. Army Research Laboratory (ARL) has conducted research using a rectangular-shaped capacitively coupled loop (CLL) and monopoles. Within the past few years, ARL has conducted research on three-dimensional (3-D) arrangements and random orientations of metamaterials. The rectangular-shaped metamaterials in 3-D arrangements were simulated using computer software, which showed pretty good results. Therefore, the CLL and monopoles in 3-D arrangements along with randomly oriented metamaterials were fabricated. This report provides details of our plan to characterize performance of the metamaterials by conducting experiments.

Low oxygen injury (LOI) in controlled atmosphere (CA) storage was positively correlated with fruit resistance to gas diffusion (R) at harvest in the McIntosh cultivar of apples ( Malus domestica Borkh). In contrast to early harvest, late harvest resulted in lower R at harvest and after storage. The longer the apples were held in CA storage, the lower was R. R was negatively correlated with whole fruit volume after storage, but not at harvest. R was negatively correlated with respiration rate at harvest, when respiration and R were high, but not after CA storage, when respiration rate and R were low. R increased and fruit volume decreased during storage at 80% relative humidity (RH), whereas the opposite occurred in a high RH (> 95%) environment. In comparison with other strains of McIntosh, Marshall McIntosh had higher R and enhanced susceptibility to LOI. And, at the same concentrations of fruit internal O 2 , Marshall McIntosh accumulated ten-fold more ethyl alcohol than did Rogers McIntosh, which indicated different thresholds for anaerobiosis in these two strains.

A realization of a negative-refractive-index (NRI) metamaterial uses a periodic structure with a unit cell composed of a capacitively loaded loop (CLL) and a conducting pole. This realization can lead to a lens mechanism with refraction focusing. This paper presents the results of a simulation of such refraction focusing using Ansoftpsilas HFSS. The simulation shows the return loss of a transmitting probe in a parallel-plate structure and the insertion loss between the transmitting probe and three receiving probes placed at the same distance from the transmitter but on the opposite side of the metamaterial slabs. The focusing at the center receiving probe is represented by the low insertion loss to the center probe compared with higher insertion losses to the other probes located at the same distance.

The (K-stopped, pi0) strangeness and charge changing reaction was investigated by producing a 12Blambda hypernucleus from a carbon target. The branching ratio for K- capture to the ground and p-shell states of this hypernucleus was found to be (0.28 +- 0.08)x10-3 and (0.35 +- 0.09)x10-3, respectively, which after correction for isospin was lower than a previously measured value for the 12C(K-stopped, pi-)12Clambda reaction, but still above the theoretical predictions for the ground state. The experiment obtained a missing-mass resolution comparable to in-flight reactions, however the higher background and lower selectivity of the K-stopped reaction limits its usefulness in experimental study of the 12C(K-stopped, pi0)12Blambda reaction.

The (K-stopped, π0) strangeness and charge changing reaction was investigated by producing a 12BΛ hypernucleus from a carbon target. The branching ratio for K- capture to the ground and p-shell states of this hypernucleus was found to be (0.28 +- 0.08)x10-3 and (0.35 +- 0.09)x10-3, respectively, which after correction for isospin was lower than a previously measured value for the 12C(K-stopped, π-)12CΛ reaction, but still above the theoretical predictions for the ground state. The experiment obtained a missing-mass resolution comparable to in-flight reactions, however the higher background and lower selectivity of the K-stopped reaction limits its usefulness in the study of new hypernuclear species.

An interim measure has been approved to reduce some of the deficiencies of MIL-STD-285, which provides a method of measuring the attenuation characteristics of electromagnetic shielding enclosures. The charges will be included in MIL-STD-907B, engineering and design criteria for shelters, expandable and non-expandable. The revised EMI (electromagnetic interference) test parameter is aimed at reducing the variations of measurement technique and improving measurement repeatability and reliability in magnetic field (low-impedance) tests. The electric field measurement is optional, and therefore can be eliminated. The plane wave and electric field test procedure is the same as for MIL-STD-285. >