Study on Scientific Analysis about Red Pigment And Binder - The Korean Ancient Red Pottery -

From the collection of the National Kimhae Museum, qualitative analyses using microscopic observation, SEM-EDS, Raman spectroscopy, FT-IR-ATR spectroscopy, and GC-MS were conducted on three burnished red potteries—Jeoksaekmaoyeonwa burnished red pottery (Neolithic age red pottery), Dandomaoyeonwan burnished red pottery(Bronze age red pottery) and Jeoksaekmaoyeongajimun burnished red pottery(Bronze age red pottery)—to investigate the components of the red pigments and the binder. After the layers of the primer were separated from the red surface, crystals of red pigment particles and minerals were found on the red surface. Through SEM-EDS, Raman estimates that the red pigment is Among soil pigments with iron oxide(Fe2O3) as the main color development source, Red Ocher(Fe2O3). A band characteristic of the Urushiol polymer was detected in the FTIR-ATRspectra(4000∼600cm-1), GC-MS analysis confirmed the presence of the benzenemethanol-2-prophenyl, 4-heptylphenol, 1-tetracecanol, heptafluorobutyric texidecane, all of which are the ingredients of the directional structure of the lacquer present in the red layer. Therefore, it seemed that the three burnished red pottery: Jeoksaekmaoyeonwan pottery(Neolithic age burnished red pottery), Dandomaoyeonwan pottery(bronze age burnished red pottery) and the Jeoksaekmaoyeongajimun pottery(bronze age burnished red pottery) made by mixing minerals and Red Ocher(Fe2O3), with lacquer.

Algorithm for the Fewest Arms Required by Multi-Band Linear Dipole Antenna

Small linear dipole antennas with a multi-band characteristic are necessary for many strip or bar shaped gateway devices of the Internet of Things (IoT), for the connectivity in various communication protocols. However, the conventional methodology of designing multi-band dipole antennas is generally empirically based. More frequency bands usually mean even more arms/slots, which results in an increasingly bulky antenna. In this paper, we will introduce an algorithm of using the fewest arms to design a multi-band linear dipole antenna. This algorithm is based on sharing arms after the effective ranges of mode excitation are determined by characteristic mode analysis (CMA). By this algorithm, an exemplified designed penta-band dipole antenna is effective in covering 433, 868, 1176, 1575, and 2450 MHz bands for LPWAN, GNSS, and ISM applications, with only 2.5 pairs of arms. 50% of arms are reduced in comparison to traditional methods. This algorithm is convenient in practical dipole antenna design, and greatly simplifies the antenna structure so that they could be mounted into small IoT devices.

Algorithm for the Fewest Arms Required by Multi-Band Linear Dipole Antenna

Small linear dipole antennas with a multi-band characteristic are necessary for many strip or bar shaped gateway devices of the Internet of Things (IoT), for the connectivity in various communication protocols. However, the conventional methodology of designing multi-band dipole antennas is generally empirically based. More frequency bands usually mean even more arms/slots, which results in an increasingly bulky antenna. In this paper, we will introduce an algorithm of using the fewest arms to design a multi-band linear dipole antenna. This algorithm is based on sharing arms after the effective ranges of mode excitation are determined by characteristic mode analysis (CMA). By this algorithm, an exemplified designed penta-band dipole antenna is effective in covering 433, 868, 1176, 1575, and 2450 MHz bands for LPWAN, GNSS, and ISM applications, with only 2.5 pairs of arms. 50% of arms are reduced in comparison to traditional methods. This algorithm is convenient in practical dipole antenna design, and greatly simplifies the antenna structure so that they could be mounted into small IoT devices.

Cuboidal quad-port UWB-MIMO antenna with WLAN rejection using spiral EBG structures

This study presents a novel configuration of a cuboidal quad-port ultra-wideband multiple-input and multiple-output antenna with WLAN rejection characteristics. The designed antenna consists of four F-shaped elements backed by a partial ground plane. A 50 Ω microstrip line is used to feed the proposed structure. The geometry of the suggested antenna exhibits an overall size of 23 × 23 × 19 mm3, and the antenna produces an operational bandwidth of 7.6 GHz (3.1–10.7 GHz). The notched band characteristic at 5.4 GHz is accomplished by loading a pair of spiral electromagnetic bandgap structures over the ground plane. Besides this, other diversity features such as envelope correlation coefficient, and diversity gain are also evaluated. Furthermore, the proposed antenna system provides an isolation of −15 dB without using any decoupling structure. Therefore, to validate the reported design, a prototype is fabricated and characterized. The overall simulated performance is observed in very close agreement with it's measured counterpart.

Structural stability of biofilms produced from silkworm cocoon fibers

Biofilms were obtained from cocoons of the silkworm, Bombyx mori, involving the removal of sericin, extraction and solubilization of fibroin fibers, dialysis of fibroin dispersions and preparation of biofilms by the casting process. Biofilm transparency was verified by UV-Vis spectroscopy and thermal stability by thermogravimetric/differential scanning calorimetry (TG/DSC). Soon after preparation, the solidification of the fibroin solution prepared from the cocoons and extracted by the Ajisawa method was monitored until the biofilm stabilized, using Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR FT-IR) as a function of time. The results showed that there is a change in the conformation from the silk I structure (?-helix) to silk II (?-sheet). In order to improve the characterization of the biofilms obtained by the Ajisawa method and LiBr solubilization of fibroin fibers, Raman spectroscopy was used to verify stabilization of the different possible molecular conformations for the fibers in these materials, by comparison with the cocoon spectra and those of the solid (freeze-dried hydrogel) precipitated by dialysis for 72 h. By comparing the Raman spectra of the biofilms in terms of the intensities of the broadened band characteristic of amide I, it was possible to assess the conformational changes in both materials based on possible transitions between ?-sheet conformations and flexible ?-helix and ?-turn structures. The results showed a dispersion of these conformations in the biofilms generated and in the solid freeze-dried hydrogel spectrum, and the ?-sheet conformation was found to be predominant. The TG and DSC curves showed that the materials with higher ?-sheet content exhibited higher thermal resistance. Thus, the data obtained further elucidate the properties of these materials which are widely used in various processes.

Temperature wave-like oscillations on ultra-short and ultra-fast time scales -INVITED

Recent findings in the frame of temperature wave-like oscillations on the ultra-short, ultra-fast time scales in solid states devices are here reviewed. The possibility for wave-like temperature oscillations are investigated at the light of the pass-band characteristic in w-k space for the temperature scalar field. The bandpass filter characteristics are accessed in terms of the heat carriers scattering times. The concepts here reviewed are of interest for perspective design of novel thermal nano-devices.