Spectral fluctuation properties of spherical nuclei

The spectral fluctuation properties of spherical nuclei are considered by use of NNSD statistic. With employing a generalized Brody distribution included Poisson, GOE and GUE limits and also MLE technique, the chaoticity parameters are estimated for sequences prepared by all the available empirical data. The ML-based estimated values and also KLD measures propose a non regular dynamic. Also, spherical odd-mass nuclei in the mass region, exhibit a slight deviation to the GUE spectral statistics rather than the GOE.Comment: 10 pages, 2 figure

A laterally driven capacitive RF MEMS switch using parylene as dielectric layer

In this paper, we propose a novel laterally driven RF MEMS capacitive switch using parylene as insulation dielectric, taking advantages of low temperature deposition and conformal coating of parylene. The switch consists of three parts, including CPW line, switching plates and actuated structures which are composed of single crystalline silicon (SCS) bonded on the glass substrate. Two actuated structures and switching plates are located at both lateral sides of the RF signal line, which is coated with parylene. The preliminary measured results show that the parylene can completely overlay the sidewall of the signal line and switching plates. The switching time from the open to the close state is 105 mu s, while 15.6 mu s from the close to the open state. For the switch with 80nm-thick parylene, the measured isolation is 16.2dB at 20GHz when both sides are under close state. These results verify that the parylene is a possible candidate to act as sidewall dielectric to realize the lateral capacitive switch.Engineering, Electrical & ElectronicInstruments & InstrumentationEICPCI-S(ISTP)

Triple-Mode Switchable Terahertz Metamaterial Absorber with Tunable Absorption Characteristics

Dynamically tunable terahertz metamaterial absorbers integrating with active materials have been widely explored. However, there are still problems that need to be urgently solved, such as modulation depth deficiency, a lack of multiparameter-tunable characteristics, and so on. In this paper, a multiparameter-tunable terahertz absorber composed of two concentric double-opening resonant rings is proposed. Semiconductor silicon and germanium are introduced to fill the openings, so that the absorber possesses three different absorption modes. Regulating semiconductor conductivities using different pump lasers allows dynamic switching among the three absorption modes to be realized. Adjusting the polarization angle of incident THz waves through device rotation facilitates easy and convenient modulation of the absorption amplitude. Calculation results show that the maximum modulation range for amplitude is 0 to 90.1%. Thus, due to the existence of two regulatory degrees of freedom, absorption mode switching and amplitude modulation are realized simultaneously. Most importantly, continuous modulation of the absorption amplitude is obtained at every resonant point in all three absorption modes without frequency drift. This scheme provides a new perspective for exploring future terahertz absorbers

Full-Space Wavefront Shaping of Broadband Vortex Beam with Switchable Terahertz Metasurface Based on Vanadium Dioxide

Currently, vortex beams are extensively utilized in the information transmission and storage of communication systems due to their additional degree of freedom. However, traditional terahertz metasurfaces only focus on the generation of narrowband vortex beams in reflection or transmission mode, which is unbeneficial for practical applications. Here, we propose and design terahertz metasurface unit cells composed of anisotropic Z-shaped metal structures, two dielectric layers, and a VO2 film layer. By utilizing the Pancharatnam–Berry phase theory, independent control of a full 2π phase over a wide frequency range can be achieved by rotating the unit cell. Moreover, the full-space mode (transmission and reflection) can also be implemented by utilizing the phase transition of VO2 film. Based on the convolution operation, three different terahertz metasurfaces are created to generate vortex beams with different wavefronts in full-space, such as deflected vortex beams, focused vortex beams, and non-diffraction vortex beams. Additionally, the divergences of these vortex beams are also analyzed. Therefore, our designed metasurfaces are capable of efficiently shaping the wavefronts of broadband vortex beams in full-space, making them promising applications for long-distance transmission, high integration, and large capacity in 6G terahertz communications

Efficiency and Privacy Enhancement for a Track and Trace System of RFID-Based Supply Chains

One of the major applications of Radio Frequency Identification (RFID) technology is in supply chain management as it promises to provide real-time visibility based on the function of track and trace. However, such an RFID-based track and trace system raises new security and privacy challenges due to the restricted resource of tags. In this paper, we refine three privacy related models (i.e., the privacy, path unlinkability, and tag unlinkability) of RFID-based track and trace systems, and clarify the relations among these privacy models. Specifically, we have proven that privacy is equivalent to path unlinkability and tag unlinkability implies privacy. Our results simplify the privacy concept and protocol design for RFID-based track and trace systems. Furthermore, we propose an efficient track and trace scheme, Tracker+, which allows for authentic and private identification of RFID-tagged objects in supply chains. In the Tracker+, no computational ability is required for tags, but only a few bytes of storage (such as EPC Class 1 Gen 2 tags) are needed to store the tag state. Indeed, Tracker+ reduces the memory requirements for each tag by one group element compared to the Tracker presented in other literature. Moreover, Tracker+ provides privacy against supply chain inside attacks

Improving the Water Resistance and Mechanical Properties of Feather Keratin/Polyvinyl Alcohol/Tris(Hydroxymethyl)Aminomethane Blend Films by Cross-Linking with Transglutaminase, CaCl₂, and Genipin

The high moisture sensitivity of feather keratin/polyvinyl alcohol/tris(hydroxymethyl)aminomethane (FK/PVA/Tris) blend films hinders their application in the packaging field. Thus, in order to improve the water resistance and mechanical properties of such blend films, we attempted cross-linking the blend film with cross-linking agents such as transglutaminase (TG), CaCl2, and genipin. Obvious differences in the morphology of the blended films were observed by scanning electron microscopy before and after cross-linking, indicating that cross-linking can inhibit the phase separation of the blend film. Conformational changes in the blend films after cross-linking were detected by Fourier transform infrared spectroscopy. Importantly, from examination of the total soluble mass, contact angle measurements, and water vapor permeability tests, it was apparent that cross-linking greatly improved the water resistance of the blend films, in addition to enhancing the mechanical properties (i.e., tensile strength and elongation at break). However, cross-linking was also found to reduce the oxygen barrier properties of the blend films. Therefore, cross-linking appears to be an effective method for promoting the application of FK/PVA/Tris blend films in the packaging field

Preparation and Physicochemical Properties of Blend Films of Feather Keratin and Poly(vinyl alcohol) Compatibilized by Tris(hydroxymethyl)aminomethane

Blend films of feather keratin (FK) and synthetic poly(vinyl alcohol) (PVA) that were compatibilized by tris(hydroxymethyl)aminomethane (Tris) were successfully prepared by a solution-casting method. The scanning electron microscopy (SEM) results showed that a phase separation occurred in the FK/PVA/Tris blended system. Analysis by Fourier transform infrared spectroscopy indicated that the main interactions between the three components were hydrogen bonds. In addition, X-ray diffraction analysis showed that the FK/PVA/Tris blend films were partially crystalline. The barrier properties, mechanical properties, and contact angles of the FK/PVA/Tris films were investigated to determine the effects of the PVA and Tris concentrations. More specifically, upon increasing the PVA content, the elongation at break, the hydrophilicity, and the oxygen barrier properties were enhanced. However, at a constant PVA content, an increase in the Tris content caused the oxygen permeability and the contact angle to decrease, while the tensile strength, elongation at break, and oxygen barrier properties were enhanced. These results indicated that the mechanical properties and gas resistance of the FK/PVA/Tris blend films could be successfully improved using the method described herein, confirming that this route provided a convenient and promising means to prepare FK plastics for practical applications