PURPOSE:This study investigated whether the Flash effect could be triggered using a compact single high-energy x-ray source (CHEXs) FLASH radiation therapy with or without two 30-second pauses during irradiation in mice. METHODS AND MATERIALS:The integral dose and beam time structure of the CHEXs were measured using an EBT-XD radiochromic film and a beam current transformer. Healthy C57BL/6J female mice and subcutaneous tumor models were irradiated under different conditions: sham, FLASH radiation therapy (FLASH1: delivering the total dose in 1 delivery; FLASH3: the total dose was split into 3 identical deliveries with two 30-second pauses, simulating gantry rotation time requirements in 3-field conformal radiation therapy), and conventional dose rate radiation therapy. Various total doses were administered to the corresponding normal tissues (whole body, whole thorax, whole abdomen, and skin) and tumors (CT26 and Lewis lung carcinoma). Survival status, normal tissue damage, and tumor growth suppression were recorded. RESULTS:The average dose rate of the CHEXs ranged from 244 to 388 Gy/s. For whole-body, whole-thorax, and skin irradiation, both FLASH1 and FLASH3 demonstrated protective effects. For whole-abdomen irradiation, FLASH1 exhibited a superior protective effect. No significant differences in tumor growth responses were observed between the FLASH1, FLASH3, and conventional dose rate radiation therapy groups (P > .05). CONCLUSIONS:Both CHEXs with or without two 30-second pauses during irradiation can trigger the Flash effect. This suggests that CHEXs may be beneficial for 3-dimensional conformal radiation therapy.

Nowadays, developing nickle zinc ferrites with excellent magnetic and gyromagnetic properties are of great importance for solving the matching problem of 5G communication system. However, much is discussed about soft magnetic properties, but little is reported gyromagnetic properties that is critical for microwave device applications. Herein, Nb5+ ions substituted Ni0.29Cu0.18Zn0.53NbxFe2-xO4 (x = 0.00-0.05), possessing high saturation magnetization, approriate initial permeability, high cut-off frequency and low ferromagnetic resonance linewidth (@9.55 GHz), were synthesized by low-temperature firing (900 ?). The phase structure and morphology evolutions were studied in detail. The results of morphology observations revealed that Nb-5+ substitution has significant role in determining produce compact and uniform microstructures of NiCuZn ferrites via suppress the grain growth, which further corresponding enhance the magnetic and gyromagnetic properties. As a result, a uniform and compact grain size can be obtained, corresponding to the change of magnetic and gyromagenetic properties have different trends. Enhanced magnetic and gyromagnetic performance including high initial permeability (mu' = 203 @1 MHz), saturation magnetization (4 pi Ms = 3966 Gauss) and low ferromagnetic resonance linewidth (delta H = 203 Oe) of the NiCuZn ferrites is achieved though adjusting Nb-5+ ions substitution. More importantly, this work not only for low temperature co-fired ceramic (LTCC) technology but also for high frequency and microwave frequency devices including phase shifter and radars.

Herein, Sm-Ga ions substituted MgCd ferrite (Mg(0.77)Cd(0.23)Fe(2-2)xSmxGaxO(4), x = 0.00-0.20) were synthesized via solid state method at low temperature using 2 wt% B2O3-Bi2O3-SiO2-ZnO glass (BBSZ glass) additive. Sm-Ga substitution did not change the spinel phase formation of ferrite. SEM showed that the grain size first increased and then decreased, while the bulk density displayed the opposite trend and the maximum density was 4.646 g/cm3 at x = 0.10. Owing to Sm-Ga ions substitution, saturation magnetization (Ms) first increased, and then decreased, while the coercivity (Hc) decreased first, and then increased. At x = 0.10, the maximum Ms was 25.33 emu/g, and the minimum Hc was 28.82 Oe. The real part of magnetic permeability reached a maximum ( mu' = 56.02 @x = 0.15) and then dropped down. The ferromagnetic resonance linewidth (at 9.56 GHz) was easily influenced by the Sm-Ga ions substitution, with the minimum value of 251.29 Oe at x = 0.10. Hence, the material has potential for microwave devices applications.

Recently, the yttrium iron garnet (Y3Fe5O12, YIG) ferrite material is widely applied in the microwave devices due to its good frequency stability and loss magnetic loss. In this work, Y3-xCaxIn0.6GexFe4.4-xO12 (x = 0.0-0.6 with a step of 0.1) materials were synthesized by the conventional solid-state reaction method. The effects of Ca-Ge co-substitution on the microstructural, dielectric and magnetic properties of YInIG materials were investigated. Ca-Ge co-substitution did not change the phase formation of YInIG ferrite, and enhanced dielectric and magnetic properties of samples. The high saturation magnetization (4pMs), low dielectric constant (epsilon(r)), low dielectric loss (tan delta(epsilon)), small coercivity (H-c) and narrow ferromagnetic resonance (FMR) linewidth (Delta H) were obtained for high frequency microwave device application. When substituted content x = 0.4, Y2.6Ca0.4In0.6Ge0.4Fe4O12 has the optimum microwave properties: epsilon(r) = 13.884@10.8 GHz, tan delta(epsilon) = 3.053 x 10(-4), H-c = 22.75 Oe, 4 pi M-s = 1226.83 Gs, Delta H = 19.3 Oe. The narrow FMR linewidth and low loss dielectric loss of the investigated samples suggested the possible use of these materials in high frequency applications. (C) 2021 Elsevier B.V. All rights reserved.

In this study, Zn2+-substituted Li2MgSiO4 ceramics (Li-2(Mg1-xZnx)SiO4, x = 0.00, 0.05, 0.10, 0.15, and 0.20) were synthesized using a traditional solid-state method. A fixed amount of LiF sintering aid (1.5 wt%) was added to the ceramics for decreasing the sintering temperature and adjusting their microwave dielectric properties. X-ray diffraction (XRD) results revealed no secondary phases, and scanning electron microscopy (SEM) data suggest that the Zn2+ ion substitution increased the size and uniformity of the grains, thereby affecting the densification of the prepared ceramics. The maximum bulk density (2.94 g/cm(3)) was found in a Zn2+ ion-substituted ceramic with x = 0.10 at a relative density of 94.2% (compared with the XRD theoretical density). Excellent microwave dielectric properties (epsilon(r) = 6.28, Q x f = 50400 GHz, and tau(f) =-145 ppm/degrees C) can also be obtained at this zirconium content. We believe that the developed ceramics are promising for use as antenna substrates or transmit/ receive modules in low-temperature co-firing ceramic applications.

Herein, In-doped Y3Fe5-xInxO12 (x = 0.00-0.75 with a step of 0.15) material was fabricated via solid state route. Mixed powders were sintered at 1450 degrees C for 6 h in the air. The microstructure and magnetic properties were examined by X-ray diffraction (XRD), Scanning electron microscope (SEM), Raman spectra, Vibrating sample magnetometer (VSM), and ferromagnetic resonance (FMR). Results show that In3+ ion substitution did not change crystal type of YIG ferrite and increased bulk density. SEM observations indicate that doped In3+ ion not only entered the crystal but also affected the grain size. According to VSM results, by increasing In3+ ion content from x = 0.00 up to x = 0.75, saturation magnetization (M-s) enhanced from 25.8 emu/g to 28.21 emu/g (x = 0.45). Then, M-s declined to 19.33 emu/g. Furthermore, narrowest FMR line width (Delta H) was obtained (Delta H = 36.7 Oe at x = 0.45) based on In-doping. The proposed material has potential for use in antenna or high-frequency applications in phase shifter, circulator, and microwave high-frequency components.

New high-performance materials have attracted much attention due to ever-increasing demands for advanced communication technologies. In present work, Ge-doped Li3+xMg2Nb1-xGexO6 (0 <= x <= 0.08) ceramics are prepared via solid-state reaction route. Microstructural analysis and crystal structure refinement reveal that moderate substitution can promote grain growth and modify crystal structure, thus enhancing microwave dielectric properties of composites. In that sense, special attention is paid to the behavior of dielectric constant er, quality factor Qxf, and frequency temperature coefficient tau(f) of final products. In these systems, er parameter depends on the density, miscellaneous phases, and polarizability; Qxf value is shown to be influenced by Nb-O bond energy, grain size, and bulk density; finally, tau(f) characteristic refers to Nb-O bond valence and NbO6 octahedral distortion. Among above ceramics, Li3.02Mg2Nb0.98Ge0.02O6 composite sintered at 1250 degrees C exhibits outstanding microwave absorption performance with tau(f) = 15.32, Qxf = 969 88 GHz, and tau(f) = -8.25 ppm/?C.

The compounds La0.67Pb0.33Mn1−xFexO3 (0 ≤ x ≤ 0.10) have been fabricated by ceramic procedures mainly to investigate their structure, magnetic phase transition and magnetocaloric effect. All samples have a rhombohedral structure belonging to $$R\overline {3} C$$ space group by structural analysis. As the Fe concentration x increases up to 0.10, Curie temperature value significantly decreases from 360 to 210 K. The maximum values of MEC (magnetic entropy change) are found to be 4.17, 2.99, 2.58 J kg−1 K−1 under 5 T field change for x = 0, 0.05, 0.10, respectively. The corresponding values of RCP (relative cooling power) are 229.8, 235.4, 216.5 J kg−1. The relatively large MEC, high RCP values and the convenient adjustment of the TC suggest that the prepared La0.67Pb0.33Mn1−xFexO3 compounds could be appropriate materials for magnetic cooling in a wide working temperature range. The analysis of isothermal magnetization using the Arrott curves and Franco’s universal method reveals that the La0.67Pb0.33Mn1−xFexO3 manganites show a second-order ferromagnetic–paramagnetic transition.

Yttrium doped strontium titanate with A-site deficiency ((Y(0.08)Sr(0.92))(1-x)TiO(3-delta)) was synthesized by conventional solid state reaction. The deficiency limit of A-site in (Y(0.08)Sr(0.92))(1-x)TiO(3-delta) is below 6 mol% in Ar/H(2) (5%)at 1500 degrees C. The sinterability of (Y(0.08)Sr(0.92))(1-x)TiO(3-delta) samples decreases slightly with increasing A-site deficiency level (x). The ionic conductivity of (Y(0.08)Sr(0.92))(1-x)TiO(3-delta) samples increases while the electronic conductivity decreases with increasing A-site deficient amount The defect chemistry analysis indicates that the introduction of A-site deficiency results in not only the increase of oxygen vacancy concentration but also the decrease of Ti(3+)-ion concentration. The latter plays the main role in the electrical conduction. (Y(0.08)Sr(0.92))(1-x)TiO(3-delta)shows good thermal-cyclic performance in electrical conductivity and has an excellent chemical compatibility with YSZ electrolyte below 1500 degrees C (C) 2008 Elsevier B.V. All rights reserved.

Strontium titanate with perovskite structure is one of potential candidates for alternative anodes for solid oxide fuel cells. Co-doped Y0.08Sr0.92TiO3-delta was synthesized via solid-state reaction. The effect of Co-doping on the electrical behavior of Y0.08Sr0.92TiO3-delta was investigated and a doping mechanism was proposed. Compared with Y0.08Sr0.92TiO3-delta, the electrical conductivities of Y0.08Sr0.92CoxTi1-xO3-delta decrease obviously with increasing Co-doping amount at 25-1000 degrees C, while the ionic conductivities increase significantly at 500-1000 degrees C. The addition of Co can increase the oxygen vacancy concentration and enlarge the saddle point critical radius r(c), both of them should be responsible for the remarkably enhanced ionic conductivity of Y0.08Sr0.92CoxTi1-xO3-delta. The decreased electronic conductivity of Y0.08Sr0.92CoxTi1-xO3-delta is ascribed to the lowered Ti3+ concentration, caused by the substitution of Co3+. Co-doping increases the oxygen absorption temperature, and thus widens the operation temperature range of doped-SrTiO3. (C) 2008 Elsevier B.V. All rights reserved.

La and Sc co-doped SrTiO3 was synthesized via solid state reaction. The oxygen ion migration energy was investigated by first-principles calculations in SrBO3 systems (B=Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Ga, Ge, As, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Sn and Sb) with perovskite structure. Structure with Sc showed the lowest oxygen migration energy, and thus Sc was selected as B-site dopant with the primary aim to improve the ionic conductivity of SrTiO3-based anode materials. With increasing Sc-doping amount, the electrical conductivity of La0.3Sr0.7ScxTi1−xO3−δ decreased in 25–1000°C, while the ionic conductivity increased significantly between 500 and 1000°C. The ionic conductivity for La0.3Sr0.7Sc0.10Ti0.90O3−δ was 1×10−2Scm−1 and increased about 230% compared with La0.3Sr0.7TiO3−δ at 800°C and under oxygen partial pressure of 10−19atm. Sc-doping increased the oxygen vacancy concentration and decreased the oxygen migration energy, thus facilitating the conduction process of oxygen ions in La and Sc co-doped SrTiO3. The possible charge compensation mechanism of Sc-doped La0.3Sr0.7TiO3−δ can be described as La0.3Sr0.7Scx3+Ti0.7-2δ-x14+Ti0.3+2δ-x23+O3-(δ+x1/2) (x=x1+x2).

Y-doped SrTiO3 was synthesized via solid-state reaction. The effects of Y-doping on the sinterability and the electrical conductivity of YxSr1−xTiO3 were investigated. Y-doping can increase the sintering activity and the electrical conductivity of SrTiO3 when yttrium amount is less than 0.09 in YxSr1−xTiO3. Excessive yttrium will cause the generation of an insulating phase Y2Ti2O7, which impedes the densification process and decreases the electrical conductivity of YxSr1−xTiO3 material. With the increased temperature, the electrical conductivity of Y-doped SrTiO3 increases first and then decreases gradually, showing a mixed conduction behavior of semi-conductors and metals. The optimized Y0.09Sr0.91TiO3 possesses an electrical conductivity on the order of 32.5–195.8Scm−1 in the temperature range of 25–1000°C and being 73.7Scm−1 at 800°C in forming gas. The thermal cycling in air does not remarkably affect the electrical conductivity and the conduction behavior of Y0.09Sr0.91TiO3 at high temperatures. Y0.09Sr0.91TiO3 displays a relatively stable electrical conductivity at different oxygen partial pressures and excellent chemical compatibility with YSZ at temperatures lower than 1300°C.