In our study, the focus was on the photocatalytic performance due to its important applications. All the chemicals used were of high purity and commercial grade without the need for purification. The thermal solvent method was used to prepare UiO-66. The UiO-66/g-Cr/PANI composite was synthesized by combining ZrCl4, BDC, and H2CrO4. The resulting UiO-66/g-Cr catalysts were identified as UiO-66, UiO-66/g-Cr-10%, UiO-66/g-Cr-20%, UiO-66/g-Cr-30%, and UiO-66/g-Cr-40%, according to the weight percentages of g-Cr: 0 wt%, 10 wt%, 20 wt%, 30 wt%, and 40 wt%, respectively. The compound was identified by X-ray diffraction analysis, which was found to be consistent with the standard card known for this compound, and the study proved that the absorption of UiO-66/Cr samples was in the visible light range with band gap energies ranging from 2.13 to 2.88 eV. The synthesized UiO-66/g-Cr compounds showed highly efficient degradation of DMNP with a short half-life (t1/2 of 2.17 min) at pH 7 under visible light irradiation. The absorption effect and degradation efficiency of pure U-66 oxide is 56.98% while that of U-66/g-Cr-40% is 61.58% within 150 min under UV light. It can be said that the addition of chromium, even in a small proportion, greatly improved the degradation efficiency in the photocatalytic stage.
Samples of parent lithium borate glasses of basic composition (70B(2)O(3)-30Li(2)O) mol% in addition to other samples that contain the gradual increase of samarium oxide (Sm2O3) at the expense of boron oxide were synthesized and characterized to investigate structural modifications, optical activation, and enhanced radiation shielding. Adding Sm2O3 caused progressive conversion of trigonal BO3 units to tetrahedral BO4 units due to charge compensation requirements, disrupting the borate network. This was evidenced by FTIR spectra showing systematic band shifts and intensity variations indicating structural changes. The fraction of 4-coordinated boron rose linearly from 0.35 to 0.54 with increasing Sm2O3 content. UV/vis absorption spectra revealed growing the f-f transition peaks of Sm3+ and charge transfer bands with Sm2O3 content. Glass density and the effective atomic number increased markedly with Sm2O3 doping, elevating gamma radiation attenuation 2-3 fold across diagnostic to radiotherapy energies due to the high samarium atomic mass and abundant outer electrons. Sm3+ containing lithium borate glasses thus demonstrate tunable structure, visible emission, and radiation shielding by optimal Sm2O3 additions between 2.5-15 mol%. Potential applications in optical devices and radioprotective materials can leverage these benefits.
This research explores a novel approach to achieving enhanced electron energy gain through tightly focused beat wave laser acceleration, supported by a helical wiggler magnetic field. The technique utilizes the intense electromagnetic fields produced by high-power laser pulses to accelerate electrons to relativistic speeds over short distances, addressing the limitations of conventional RF (Radio Frequency) accelerators. By employing two tightly focused laser pulses with slightly varying frequencies and identical polarizations, the resulting beat wave coupled with the helical wiggler field enables substantial electron energy amplification. The study incorporates detailed mathematical analyses, including the derivation of electric and magnetic field components, Lorentz force equations, and momentum-energy relations, offering a comprehensive understanding of the underlying electron acceleration dynamics. This method presents a promising advancement in producing high-energy electron beams in vacuum environments, with potential applications in particle acceleration and high-energy physics.
Nonlinear optical response in new copolymer of polyester (polyvinyl alcohol grafted Rhodamine B) (CPPS-PVA-g-RhB) was used to realize passive all-optical switches and limiters. However, there is still a need, respectively, for passive all-optical switches and limiters with an optimization of the optical figures of merit with critical parameters and a low optical limiting threshold as possible. The all-optical switching and limiting effects of the CPPS-PVA-g-RhB were investigated. The results showed that with a modulation depth of 67% and a switching contrast of 4.8 dB at a switching time of 40 ms, the CPPS-PVA-g-RhB can provide all-optical switches at a pump power of 38 mW. With optical damage of 24.8 mW and a dynamic range of 1.32, the CPPS-PVA-g-RhB leads to realize all-optical limiters at an optical limiting threshold of 18 mW.
In this paper, we have analyzed the effects of beam waist (omega 0) on second harmonic generation (SHG) in the presence of 1-dimension diffraction effect at phase-matching condition. The fundamental wave is modelled as a Gaussian beam and depletion, incident with beam waist at the entrance plane of the nonlinear crystal to generate second harmonic waves. Specifically, we simulate the SHG intensity profile using a Gaussian fundamental beam, converting 1560 nm laser light to 780 nm, having length 20 mm with an effective nonlinear coefficient of 3 pm/V. The simulation results (in 3-Dimension) reveal a significant increase in SHG conversion efficiency as the beam waist increases from 50 & micro;m to 120 & micro;m for short normalize crystal lengths. However, at longer normalize crystal lengths, the efficiency decreases due to the effects of diffraction, highlighting the critical balance between incidence beam and diffraction in optimizing SHG performance.
