[en] The cross sections of ^natNi(γ, xn)^57,56Ni and ^natNi(γ, pxn)^58-55Co reactions induced by bremsstrahlung end-point energies of 65 and 75 MeV were measured by using the method of activation along with off-line γ-ray spectrometric technique. The ^natNi(γ, xn)^57,56Ni and ^natNi(γ, pxn)^58-55Co reaction cross sections as a function of photon energy were also calculated by using TALYS 1.9 code. The flux-weighted average values at different end-point energies were obtained from the literature data, as well as from the theoretical values of TALYS and TENDL-2017 data library based on mono-energetic photons. Those were compared with the experimental data of present work and found to be in general agreement. It was also found that the experimental and theoretical cross-sections data increase with bremsstrahlung energy up to a certain value. After that the individual reaction cross sections slightly decrease with the increase of bremsstrahlung energy due to the opening of other reactions. As an example, the ^natNi(γ, xn)⁵⁷Ni reaction cross section decreases when the ^natNi(γ, xn)⁵⁶Ni reaction opens up. Similarly, the ^natNi(γ, pxn)⁵⁸Co reaction cross section decreases when ^natNi(γ, pxn)⁵⁷Co reaction opens up and so on. These observations indicate the role of excitation energy and its portion in different reaction channels. (author)

[en] This work demonstrates a broad-band negative refractive index (NRI) by using the hybridization effect of dish-net dimer metamaterials (MMs), in the GHz frequency regime. Two symmetric layers of dishnet structure are expected to realize a wideband of negative refractive index with a high transmitted power of 88%, a high figure of merit of 26 at 15.2 GHz and to make the MM insensitive for polarization/wide-incident angle of electromagnetic wave. By adjusting the distance between these layers and their dielectric thickness, the NRI bandwidth are flexibly controlled. Further study indicates that the refractive index strongly depends on tangent loss of the dielectric substrate and number of hybridized modes. Also, we numerically investigate the hybridization characteristic in various operational frequency ranges. The performance of the proposed metamaterial is numerically, theoretically and experimentally demonstrated. This paper strengthens the novelty and computation of NRI metamaterials. (paper)

[en] We measured the cross sections for the formation of the ground state nucleus ^100gRh through ^natPd(p,x)^100m,gRh reactions. The experiment was carried out using the stacked-foil activation technique in the energy range from threshold to 42.61 MeV. The cross section was determined on the basis of the measured activity of the corresponding residual nucleus using a high energy resolution HPGe γ-ray detector. The energy dependent flux of the proton beam was determined using the ^natCu(p,x)⁶²Zn and ^natCu(p,x)⁶⁵Zn monitoring reactions. In order to enhance the accuracy of the experimental results, the activity contributions from the decay of the ^100mAg, ^100gAg and ¹⁰⁰Pd to ^100gRh, which were also produced in the same palladium foil were corrected. The present experimental results are compared with the previously published data and with the theoretical predictions from the TENDL-2017 library. (author)

[en] Using an irreducible design we experimentally and numerically study a perfect metamaterial absorber, providing excellent absorption at microwave frequencies. The impact of geometric parameters on the absorption is also investigated. The experimental and the simulated results are in good agreement. Finally, we propose a polarization-insensitive absorber for the improvement. (paper)

[en] We proposed a multi-band metamaterial absorber (MA) based on high-order magnetic resonance using ring-shaped structures. We obtained three absorption peaks at 4.71 GHz (the fundamental resonance), 13.39 GHz (the third-order behavior), and 19.91 GHz (the fifth-order behavior) with correspondent absorptions of 90%, 100%, and 99.33%, respectively. Therefore, these high-order perfect absorptions are the potential to make the easier fabrication for the next generation of MAs, especially in high-frequency regions. Particular, the obtained results are further controlled using the LC circuit model. Besides, by scaling down the unit-cell size, the third-and fifth-order absorptions are created in the THz frequency band. (author)

[en] The silver nanoparticles (AgNPs)/peco fabrics were prepared by immobilization of AgNPs on fabrics in which AgNPs were synthesized by γ-irradiation of the 10 mM AgNO₃ chitosan solution at the dose of 17.6 kGy. The AgNPs size has been estimated to be about 11 nm from TEM image. The AgNPs content onto peco fabrics was of 143±6 mg/kg at the initial AgNPs concentration of 100 ppm. The AgNPs colloidal solution was characterized by UV–vis spectroscopy and TEM image. The antibacterial activity of AgNPs/peco fabrics after 60 washings against Staphylococcus aureus and Klebsiella pneumoniae was found to be over 99%. Effects of AgNPs fabics on multidrug-resistant pathogens from the clinical specimens were also tested. - Highlights: • AgNPs were synthesized by gamma Co-60 irradiation of Ag⁺/chitosan solution. • AgNPs/peco fabric was prepared by deposition of AgNPs on peco fabric. • AgNPs/peco fabric was tested as wrapper of patient’s bed in hospital. • AgNPs/peco fabric wrapper inhibited the growth of bacterial strains remarkably.

[en] Highlights: • The yield ratios of the ^85m,gSr formed in the ^natSr(γ,xn) reactions were measured using the off-line activation method. • The results with bremsstrahlung end-point energies of 55- and 60-MeV have been measured for the first time. - Abstract: The yield ratios of ^85m,gSr were measured in the ^natSr(γ,xn)^85m,gSr reactions with the bremsstrahlung end-point energies of 55-, 60-, and 65-MeV. The experiment was carried out by the activation method in combination with high resolution HPGe γ-ray spectroscopy. In order to improve the accuracy of the experimental results, appropriate experimental procedure was used to reduce the influence of the strong annihilation peak (511 keV) to the 514 keV γ-ray peak of ^85gSr. The experimental results are compared to theoretical predictions using code TALYS-1.6. The present results for 55-, and 60-MeV bremsstrahlung end-point energies have been measured for the first time.

[en] The isomeric yield ratios of ^99m,gRh, ^101m,ggRh, and ^102m,gRh isomeric pairs produced from the ^natPd(γ,pxn) reactions were measured with the bremsstrahlung end-point energies of 50-, 55-, 60-, 65-, and 70-MeV at the 100 MeV electron linac of the Pohang Accelerator Laboratory, Korea. The measurements were carried out with the activation method in combination with off-line γ-ray spectrometry. In order to improve the accuracy of the activity measurements, the separation of the overlapping γ-rays and the necessary corrections for the counting losses were made. The new experimental results are compared with the theoretical values of the TALYS-1.6 code. - Highlights: • Measurement of isomeric yield ratios of ^{99m,g;101m,g;102m,g}Rh in the ^natPd(γ,pxn) reactions, • The present results measured with the bremsstrahlung end-point energies of 50–70MeV are reported for the first time, • The present isomeric yield ratios are compared with the theoretical values using the TALYS-1.6.

[en] Mn-Ga-Al/Fe-Co nanocomposite hard magnetic materials were combined from hard magnetic and soft magnetic phases. The nanoparticles of hard and soft magnetic phases were fabricated by using high energy ball milling method with milling times of 8 h and 32 h to have size of about 50 nm and 70 nm, respectively. The hard and soft magnetic phases were then mixed together for 1 h with different weight fractions of soft magnetic phase from 5 to 20%. The nanocomposites show quite good exchange-spring coupling of hard and soft magnetic phases. Saturation magnetization and coercivity of the nanocomposites strongly depend on the weight fraction of the soft magnetic phase. The increases rapidly, while the decreases with increasing the fraction of the soft magnetic phase. With appropriate fabrication conditions, the Mn-Ga-Al/Fe-Co nanocomposites can possess emu g⁻¹ and . Maximum energy products, , above 4 MGOe have been achieved for this kind of rare earth-free hard magnetic materials. (paper)

[en] We measured the flux-weighted average cross-sections and the isomeric yield ratios of "9"9"m","g","1"0"0"m","g","1"0"1"m","g","1"0"2"m","gRh in the "1"0"3Rh(γ, xn) reactions with the bremsstrahlung end-point energies of 55 and 60 MeV by the activation and the off-line γ-ray spectrometric technique, using the 100 MeV electron linac at the Pohang Accelerator Laboratory (PAL), Korea. The flux-weighted average cross-sections were calculated by using the computer code TALYS 1.6 based on mono-energetic photons, and compared with the present experimental data. The flux-weighted average cross-sections of "1"0"3Rh(γ, xn) reactions in intermediate bremsstrahlung energies are the first time measurement and are found to increase from their threshold value to a particular value, where the other reaction channels open up. Thereafter, it decreases with bremsstrahlung energy due to its partition in different reaction channels. The isomeric yield ratios (IR) of "9"9"m","g","1"0"0"m","g","1"0"1"m","g","1"0"2"m","gRh in the "1"0"3Rh(γ, xn) reactions from the present work were compared with the literature data in the "1"0"3Rh(d, x), "1"0"2"-"9"9Ru(p, x), "1"0"3Rh(α, αn), "1"0"3Rh(α, 2p3n), "1"0"2Ru("3He, x), and "1"0"3Rh(γ, xn) reactions. It was found that the IR values of "1"0"2","1"0"1","1"0"0","9"9Rh in all these reactions increase with the projectile energy, which indicates the role of excitation energy. At the same excitation energy, the IR values of "1"0"2","1"0"1","1"0"0","9"9Rh are higher in the charged particle-induced reactions than in the photon-induced reaction, which indicates the role of input angular momentum. (orig.)