Critical Point of the 152Sm, 154Gd,and 156Dy Isotones

Physics of Atomic Nuclei - The even—even rare-earth nuclei in U(5)—SU(3) region at neutron number (N) = 90, have been systematically studied using the Bohr—Mottelson Model (BM),...     

A novel secure image transmission scheme based on synchronization of fractional-order discrete-time hyperchaotic systems

In this paper, a secure image transmission scheme based on synchronization of fractional-order discrete-time hyperchaotic systems is proposed. In this scheme, a fractional-order modified-Hénon map is considered as a transmitter, the system parameters and fractional orders are considered as secret keys. As a receiver, a step-by-step delayed observer is used, and based on this one, an exact synchronization is established. To make the transmission scheme secure, an encryption function is used to cipher the original information using a key stream obtained from the chaotic map sequences. Moreover, to further enhance the scheme security, the ciphered information is inserted by inclusion method in the chaotic map dynamics. The first contribution of this paper is to propose new results on the observability and the observability matching condition of nonlinear discrete-time fractional-order systems. To the best of our knowledge, these features have not been addressed in the literature. In the second contribution, the design of delayed discrete observer, based on fractional-order discrete-time hyperchaotic system, is proposed. The feasibility of this realization is demonstrated. Finally, different analysis are introduced to test the proposed scheme security. Simulation results are presented to highlight the performances of our method. These results show that, our scheme can resist different kinds of attacks and it exhibits good performance.     

Optical band gap and conductivity measurements of polypyrrole-chitosan composite thin films

Electrical conductivity and optical properties of polypyrrole-chitosan（PPy-CHI） conducting polymer composites have been investigated to determine the optical transition characteristics and energy band gap of composite films.The two electrode method and I-V characteristic technique were used to measure the conductivity of the PPy-CHI thin films,and the optical band gap was obtained from their ultraviolet absorption edges.Depending upon experimental parameter,the optical band gap（E_g） was found within 1.30-2.32 eV as estimated from optical absorption data.The band gap of the composite films decreased as the CHI content increased.The room temperature electrical conductivity of PPy-CHI thin films was found in the range of 5.84×10^-7-15.25×10^-7 S·cm^-1 depending on the chitosan content.The thermogravimetry analysis（TGA） showed that the CHI can improve the thermal stability of PPy-CHI composite films.     

Synthesis and properties of poly(hydroxamic acid) from crosslinked poly(methacrylate)

Poly(hydroxamic acid) chelating ion-exchange resin was prepared from crosslinked poly(methacrylate) beads. The starting polymer was prepared by a suspension polymerization of methacrylate and divinyl benzene. Conversion of the ester groups into the hydroxamic acid was carried out by treatment with hydroxylamine in an alkaline solution. Hydroxamic acid capacity of the product was 2.71 mmol/g. The resin exhibited high affinity towards Fe(III) and Pb ions and its capacities for Fe(III), Pb, Cu, Ni and Co ions were pH dependent. The ability of the resin to carry out the separation of Fe(III)CuCo/Ni and PbNi ions is also reported.     

XRD and AFM studies of ZnS thin films produced by electrodeposition method

The structure and morphology of ZnS thin films were investigated. ZnS thin films have been grown on an indium tin oxide glass substrate by electrodeposition method using zinc chloride and sodium thiosulfate solutions at room temperature. The X-ray diffraction patterns confirm the presence of ZnS thin films. From the AFM images, grain size decreases as the cathodic potential becomes more negative (from ?1.1 to ?1.3 V) at various deposition periods. Comparison between all the samples reveals that the intensity of the peaks increased, indicating better crystalline phase for the films deposited at ?1.1 V. These films show homogeneous and uniform distribution according to AFM images. On the other hand, XRD analysis shows that the number of ZnS peaks increased as deposition time was increased from 15 to 30 min at ?1.1 V. The AFM images show thicker films to be formed at ?1.1 V indicating more favourable condition for the formation of ZnS thin films.     

Multimode interference wavelength multi/demultiplexer for 1310 and 1550 nm operation based on BCB 4024-40 photodefinable polymer

A 1310 and 1550 nm coarse wavelength multi/demultiplexer based on benzocyclobutene (BCB 4024-40) polymer is demonstrated for the first time. The device is designed based on a combination of general interference and paired interference mechanisms of multimode interference (MMI). It is fabricated on BK7 glass substrate with a thin layer of SiO₂ as cover. A cost effective chemical etching technique is used in the fabrication process to take advantage of the photosensitive nature of the polymer. The device length was significantly reduced by adopting the restricted multimode interference scheme, lower beat length ratio and cascaded MMI couplers. The measured crosstalk at 1310 nm was 14.4 dB and at 1550 nm was 20.6 dB. The measured insertion loss is around 3.2-3.5 dB for both ports.     

Studies on mesoionic compounds,II. The solvent effect on the electronic absorption spectra of mesoionic 2,3-diaryl-2H-tetrazolium-5-thiolate derivatives

The electronic absorption spectra of 2,3-di(2-fluorophenyl)-, 2,3-di(4-fluorophenyl)-, 2,3-di-(2-chlorophenyl)-, 2,3-di(2-methylphenyl)-, 2,3-di(4-methylphenyl)- and 2,3-di(2-methoxyphenyl)-2H-tetrazolium-5-thiolates have been measured in pure and mixed solvents. They were found to exhibit three characteristic absorption bands at 480-380 nm, near 250 and near 210; the longest wavenlength band of which was assigned to an n → π* transition.     

Selection of Polymorphic Structure in Dihydroxystearic Acid/Octyl dihydroxystearate/RBD Palm Kernel Olein & Medium Chain Triglycerides in Cosmetic and Personal Care Formulation

Dihydroxystearic acid (DHSA) and octyl dihydroxystearate (DHSA‐octyl ester) have been successfully prepared from palm oleic acid. Preliminary results showed that these compounds are suitable in personal care and cosmetics products. The objective is to study the phase behaviors in ternary system of DHSA/DHSA‐octyl ester/RBD palm kernel olein (RBDPKOo) and medium chain triglycerides (MCT) at 85°C. The phase changes were observed through polarizing light while the formation of texture was confirmed using polarizing microscope combination with heating. From the ternary phase diagram, results showed that all ratios of DHSA/DHSA‐octyl ester were completely in two‐phase region with various concentrations of RBDPKOo/MCT. Needles and spherulite textures were found in this system. The viscosity and thixotropy of these mixtures were also determined using rheometer. DHSA and DHSA‐octyl ester has a melting point of 84.4°C and 64.3°C, respectively.