Reflection coefficient calculation of a feeder structure in a RLSA

RLSA(Radial line slot antenna) is slotted waveguide array antenna which is proposed for the DBS(Direct Broadcast from a Satellite) reception. Theoretically, it has lower conduction loss and higher effectiveness than the planar antenna using microstrip. DL-RLSA(Double-layered RLSA) uses radially inward travelling wave for the slot excitation in the double-layered radial line. The effectiveness of DL-RLSA is more than 75%(33.0~37dBi), which is two times as high effectiveness as other planar antenna. In spite of that advantage, SL-RLSA(Single-layered RLSA) is more popular because of the complex structure of DL-RLSA. But the radially outward travelling wave of SL-RLSA makes high tapering when the travelling wave approaches the aperture edge. To remove these troublesome thing, a effective feeder structure which has tilting rod is proposed in this paper. To find the optimum height and tilting angle of the feeder, the finitedifference time-domain(FDTD) method is employed. In other words, the simulation parameter of the FDTD algorithm is the dimension of feeder. Compared with the effectiveness of the conventional rod feeder structure, that of the proposed feeder structure in this paper is enhanced by 5dB

Study on fatigue experiment for transverse butt weldsunder 2G and 3G weld positions

ABSTRACTAlthough the transverse butt weld method with ceramic backing strip has been widely used in various industrial fields for its fabricational convenience, it is rarely used in offshore industries since the fatigue strength of the weld joint has not been proved sufficiently. This study conducted fatigue tests for series of butt weld specimens with horizontal (2G) and vertical (3G) welding positions in order to verify the fatigue strength compared to S-N curve by DNV (Det Norske Veritas), IIW (International Institute of Welding) and Eurocode 3. The difference of the 2G specimens and the 3G specimens are investigated in terms of angular distortion and the effect on the fatigue strength are analyzed

Case study on high-resolution monitoring network of groundwater heat pump system

With the increasing installation of shallow geothermal energy, the importance of thermal impact prediction also increases in the system design stage. In nature, it is general that heterogeneity exists and it can affect the groundwater flow as well as the transport along to the flow. When predicting heat transport under the groundwater heat pump (GWHP) operation, however, impacts of heterogeneity have rarely been considered. In this study, to detect the hydraulic and thermal feedback to the two months of GWHP operation, a dense monitoring network was constructed with 12 monitoring wells at Eumseong-gun, Republic of Korea. The temperature was monitored in high resolution via fiber-optic distributed temperature sensing. During the GWHP operation, a very dynamic flow condition was generated with the hydraulic gradient between 0.005 and 0.07. The maximum temperature change at the nearest monitoring well was 2 ?. Observed hydraulic and thermal responses showed spatially heterogeneous results. While the heterogeneous responses of hydraulic change were stronger near the geothermal wells, those of temperature change were higher near the center of the thermal plume

Estrogen Antagonist and Development of Macular Hole

To describe the clinical and optical coherence tomography (OCT) features of a macular hole (MH) or its precursor lesion in patients treated with systemic antiestrogen agents. We reviewed the medical history of the patient, ophthalmic examination, and both fundus and OCT findings. Three female patients receiving antiestrogen therapy sought treatment for visual disturbance. All of the patients showed foveal cystic changes with outer retinal defect upon OCT. Visual improvement was achieved through surgery for the treatment of MH in two patients. Antiestrogen therapy may result in MH or its precursor lesion, in addition to perifoveal refractile deposits. OCT examination would be helpful for early detection in such cases

Effect of the glyceryl monooleate-based lyotropic phases on skin permeation using in vitro diffusion and skin imaging

AbstractGlyceryl monooleate (GMO) is a polar lipid that can exist in various liquid crystalline phases in the presence of different amounts of water. It is regarded as a permeation enhancer due to its amphiphilic property. Various phases of GMO/solvent system containing sodium fluorescein were prepared to compare permeability using confocal laser scanning microscopy (CLSM). GMO was melted in a vial in a water bath heated to 45 °C. Propylene glycol and hexanediol were homogeneously dissolved in the melted GMO. Sodium fluorescein in aqueous solution was diluted to various ratios and thoroughly mixed by an ultrasonic homogenizer. Each GMO/Solvent system with fluorescein was applied onto the epidermal side of excised pig skin and incubated overnight. CLSM was performed to observe how the GMO/solvent system in its different phases affect skin permeability. Cubic and lamellar phase formulations enhanced the fluorescein permeation through the stratum corneum. A solution system had the weakest permeability compared to the other two phases. Due to the amphiphilic nature of GMO, cubic and lamellar phases might reduce the barrier function of stratum corneum which was observed by CLSM as fluorescein accumulated in the dermis. Based on the results, the glyceryl monooleate lyotropic mixtures could be applied to enhance skin permeation in various topical and transdermal formulations