No abstract available

[en] CO₂ laser beam (LB) welding is conducted on 7075-T6 aluminum alloy sheets at two different welding speeds and compared with gas tungsten arc (GTA) welding. The mechanical and microstructural characteristics of the welds are evaluated using tensile tests, hardness tests, optical microscopy and energy dispersive X-ray spectroscopy (EDS). Results indicate that both the hardness and tensile strength of LB welds are higher than those of GTA welds. It is shown that the hardness value of the softened region in LB welds is in the fusion zone (FZ), whereas that in the heat affected zone (HAZ) of the GTA weld. Tensile strengths of LB welds after the post-weld artificial aging treatment at 120 deg. C for 26 h are improved but cannot be equivalent to those of base metal because the softened FZ of the LB weld is not completely recovered after post-weld artificial treatment

[en] The tunable nanojet-induced mode achieved by coupled core–shell microcylinders with nematic liquid crystals is reported. The optical transmission properties of touching core–shell microcylinders with nematic liquid crystals are studied by using high resolution finite-difference time-domain simulation. We identify two rotation mechanisms of liquid crystal in terms of the coupling efficiency between neighboring core–shell microcylinders. The nanojet-induced guided modes depend strongly on the directors of liquid crystals. The optical transport can be continuously tuned in the core–shell microcylinder by controlling the directors of liquid crystals. The coupled core–shell microcylinders can be assembled inside hollow structures to build tunable optical waveguides for effective and low-loss guiding of photons.

[en] In this Letter, the general calculation formulas of radial matrix elements for the Hartmann potential are obtained, and the recurrence relations of different power order radial matrix elements are also derived. The relevant results of bound states for the usual hydrogen-like atom in the literature are contained in more general conclusion of this Letter as special cases

[en] Using the modified Kunstatter method, which employs as proper frequency the imaginary part instead of the real part of the quasinormal modes, the entropy spectrum and area spectrum of the modified Schwarzschild black holes in gravity's rainbow are investigated. In the current study, two cases of modified dispersion relations concerning energy dependent and energy independent speed of light are considered. The entropy spectra with equal spacing are derived in these two cases. Furthermore, the obtained entropy spectra are independent of the energy of a test particle and are the same as the one of the usual Schwarzschild black hole. Also, the same area spectrum formulas are obtained in these different dispersion relations. However, due to the quantum effect of spacetime, the obtained area spectra are not equally spaced and are different from the one of the usual Schwarzschild black hole. Besides, in these two cases, the same black hole entropy formulas with logarithmic correction to the standard Bekenstein-Hawking area formula are obtained by the adiabatic invariant. The form of area spacing formulas and entropy formulas are independent of the particle's energy, but the area spacing and entropy can have energy dependence through the area. (orig.)

[en] Soil washing using a strong chelating agent is a common practice for restoring contaminated soils, but significant soil fertility degradation and high operation costs are the major disadvantages. Washing soil with a dissolved organic matter (DOM) solution has been identified as a method that can moderate the loss of nutrients in the soil and enhance metal removal. The DOM solutions were extracted from waste sludge obtained from a local whisky distillery. Single chelating washing and chelate-DOM washing were carried out using ethylenediaminetetraacetic acid (EDTA), citric acid, and DOM solutions to remediate highly Cu-contaminated soil. Two-phase washing using 0.34 M citric acid and then 1500 mg L⁻¹ DOM solution (pH 8.5) was found to be most favorable for the soil. With this treatment, 91% Cu was removed from the topsoil; the organic matter, cation exchange capacity, plant-available nitrogen, and available phosphate content increased by 28.1%, 103%, 17.7%, and 422%, respectively. -- Highlights: •We employ dissolved organic matter (DOM) solution to partially substitute EDTA or citric acid for soil washing. •Moderately-contaminated subsoil can be successfully remediated by sequential DOM washing. •Soil fertility deteriorates if soil is washed with EDTA or citric acid alone. •The loss of soil fertility has been reduced by performing two-phase the chelate-DOM washing. -- Washing the soil with the two-phase chelate-DOM method could remove quantities of Cu and reserve most of fertility in soil

[en] The three-dimensional real-space observation of photonic nanojet-induced modes in a chain of microspheres with different diameters is reported. The optical transmission properties of a chain of microspheres are studied by using high resolution finite-difference time-domain calculation. The photonic nanojet-induced modes in different chains of microspheres are measured by using a scanning optical microscope system with an optical-fiber probe. We observe the photonic nanojet-induced modes from optical microscope images for chains of 3 μm, 5 μm, and 8 μm microspheres deposited on a patterned silicon substrate. The incident beam can be periodically reproduced in chains of dielectric microspheres giving rise to lossless periodically optical focusing with period of two diameters. Detailed theoretical and experimental data on the transmission, scattering loss, and field-of-view are presented. This waveguide technique can be used in biomedical microscopy, ultra-precise laser process, microfluidics, and nanophotonic circuits.

[en] We compare three datasets of high-resolution O₃ cross sections and evaluate the effects of using these cross sections on O₃ profile retrievals from OMI UV (270–330 nm) measurements. These O₃ cross sections include Brion–Daumont–Malicet (BDM), Bass–Paur (BP) and a new dataset measured by Serdyuchenko et al. (SGWCB), which is made from measurements at more temperatures and in a wider temperature range than BDM and BP, 193–293 K. Relative to the BDM dataset, the SGWCB data have systematic biases of −2 to +4% for 260–340 nm, and the BP data have smaller biases of 1–2% below 315 nm but larger spiky biases of up to ±6% at longer wavelengths. These datasets show distinctly different temperature dependences. Using different cross sections can significantly affect atmospheric retrievals. Using SGWCB data leads to retrieval failure for almost half of the OMI spatial pixels, producing large negative ozone values that cannot be handled by radiative transfer models and using BP data leads to large fitting residuals over 310–330 nm. Relative to the BDM retrievals, total ozone retrieved using original SGWCB data (with linear temperature interpolation/extrapolation) typically shows negative biases of 5–10 DU; retrieved tropospheric ozone column generally shows negative biases of 5–10 DU and 5–20 DU for parameterized and original SGWCB data, respectively. Compared to BDM retrievals, ozone profiles retrieved with BP/SGWCB data on average show large altitude-dependent oscillating differences of up to ±20–40% biases below ∼20 km with almost opposite bias patterns. Validation with ozonesonde observations demonstrates that the BDM retrievals agree well with ozonesondes, to typically within 10%, while both BP and SGWCB retrievals consistently show large altitude-dependent biases of up to ±20–70% below 20 km. Therefore, we recommend using the BDM dataset for ozone profile retrievals from UV measurements. Its improved performance is likely due to its better characterization of temperature dependence in the Hartley and Huggins bands. -- Highlights: • Compare 3 UV O₃ cross sections: BDM, BP, and new Serdyuchenko et al. data. • The new data show biases (−2 to 4%) vs. BDM and different temperature dependences. • Different data affect OMI O₃ profile retrieval by up to 40% on average below 20 km. • BDM retrievals agree with ozonesonde to ∼10%, others show up to ±20–70% biases. • Recommend using the BDM dataset for UV ozone profile retrieval

[en] We have experimentally investigated the enhanced effects of subluminal and superluminal propagation, based on electromagnetically induced transparency (EIT) and electromagnetically induced absorption (EIA), respectively. By adding only an incoherently pumping laser to each case, the slower subluminal group velocity, and the faster superluminal pulse propagation are, respectively, observed. By only changing the intensity of the incoherent pumping beam, we are able to control, respectively, the subluminal group velocity continuously from v_g=c/20000 to v_g=c/8300, and superluminal group velocity from v_g=-c/1667 to v_g=-c/3030. Qualitative explanations for the two cases are given

[en] Highlights: • A new emission reconstruction algorithm employing dynamic grids is established in TGS technique. • Grids are refined around emission sources which improves the detection efficiency accuracy in emission reconstruction. • The new algorithm keeps the lower error of emission reconstruction than that of fixed grids in most detection schemes. • The TGS detection time is reduced to half without losing detection accuracy if the dynamic grids are applied. - Abstract: This paper presents a new emission reconstruction algorithm employing dynamic grids for tomographic gamma scanning in order to simplify the scanning process during the detection. Five types of scanning schemes to the single-point source and multi-point sources are studied aiming at both the uniform and heterogeneous matrixes in the radioactive waste drum. Comparing with the fixed grids, the error of emission reconstruction is obviously reduced if dynamic grids are applied. This reduction occurs because the grids are refined automatically around the emission source and consequently the precise positioning of the emission source leads to the low error of detection efficiency and emission reconstruction. Moreover, the simplification of the scanning process to half has less influence on the detection precision if dynamic grids are used, which will shorten the period of TGS detection