30 research outputs found

    TeV Scale Phenomenology of e+eμ+μe^+e^- \to\mu^+ \mu^- Scattering in the Noncommutative Standard Model with Hybrid Gauge Transformation

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    The hybrid gauge transformation and its nontrivial phenomenological implications are investigated using the noncommutative gauge theory with the Seiberg-Witten map expanded scenario. Particularly, the e+eμ+μe^+e^- \to\mu^+ \mu^- process is studied with a generalized noncommutative standard model (NCSM) including massive neutrinos and neutrino-photon interaction. In this model, the hybrid gauge transformation in the lepton sector is naturally introduced through the requirement of gauge invariance of the seesaw neutrino mass term. It is shown that in the NCSM without hybrid gauge transformation the noncommutative correction to the scattering amplitude of the e+eμ+μe^+e^- \to\mu^+ \mu^- process appears only as a phase factor, predicting no new physical deviation in the cross section. However, when the hybrid feature is considered, the noncommutative effect appears in the single channel process. The cross section and angular distribution are analyzed in the laboratory frame including Earth's rotation. It is proposed that pair production of muons in the upcoming TeV International Linear Collider (ILC) can provide an ideal opportunity for exploring not only the NC space-time, but also the mathematical structure of the corresponding gauge theory.Comment: 22 pages, 8 figure

    Research on the differential tectonic-thermal evolution of Longmaxi shale in the southern Sichuan Basin

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    The southern Sichuan Basin in China holds abundant shale gas resources; however, the shale gas bearing property shows great differences due to the multiple stages of tectonic transformation. The key to revealing the shale gas differential enrichment mechanism is to explore the thermal evolution characteristics during tectonic evolution. Therefore, taking the Luzhou and Changning blocks as an example, which have obvious differences in tectonic evolution, the organic geochemical conditions of Longmaxi shale were firstly compared with the test data. Then, the thermal evolution characteristics under the background differential tectonic uplift-erosion were recovered using basin modeling techniques. The results showed that the two blocks contain similar organic geochemical conditions of the Longmaxi shale. Moreover, the hydrocarbon generation condition in Luzhou Block is greater than that in the Changning Block. Influenced by the differential tectonic evolution, the study area experienced a complex burial history and the formation of multiple unconformities. As a result, the present burial depth of Longmaxi Formation in the Luzhou Block is significantly greater than that in the Changning Block. The thermal evolution history of Longmaxi shale in the study area could be divided into three stages, including a low-temperature stage from Caledonian to Hercynian, a middle-temperature stage from Hercynian to Indosinian, and a high-temperature stage from Yanshanian to Himalayan. In addition, it was found that the Himalayan period is the main stage resulting in the differential gas bearing property of Longmaxi shale in the southern Sichuan area. Under the differential structural modification, the peak time of hydrocarbon generation in the Luzhou Block occurred earlier and the conversion rate was slightly higher than that in the Changning Block.Cited as: Zhao, L., Mao, W., Liu, Z., Cheng, S. Research on the differential tectonic-thermal evolution of Longmaxi shale in the southern Sichuan Basin. Advances in Geo-Energy Research, 2023, 7(3): 152-163. https://doi.org/10.46690/ager.2023.03.0

    Enhanced superconductivity at the interface of W/Sr2_{2}RuO4_{4} point contact

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    Differential resistance measurements are conducted for point contacts (PCs) between tungsten tip approaching along the cc axis direction and the abab plane of Sr2_{2}RuO4_{4} single crystal. Three key features are found. Firstly, within 0.2 mV there is a dome like conductance enhancement due to Andreev reflection at the normal-superconducting interface. By pushing the W tip further, the conductance enhancement increases from 3\% to more than 20\%, much larger than that was previously reported, probably due to the pressure exerted by the tip. Secondly, there are also superconducting like features at bias higher than 0.2 mV which persists up to 6.2 K, resembling the enhanced superconductivity under uniaxial pressure for bulk Sr2_{2}RuO4_{4} crystals but more pronounced here. Third, the logarithmic background can be fitted with the Altshuler-Aronov theory of tunneling into quasi two dimensional electron system, consistent with the highly anisotropic electronic system in Sr2_{2}RuO4_{4}.Comment: prb style, 9 pages, 8 fig

    High-resolution characterization of shallow aquifer by 2D viscoelastic full-waveform inversion of shallow seismic wavefield acquired at the Krauthausen test site

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    Full-waveform inversion (FWI) method has been proved as an effective tool for high-resolution imaging of the subsurface. We have investigated the potential of shallow seismic-wave 2D viscoelastic FWI as a method in high-resolution hydrogeological near-surface characterization. FWI is applied to two orthogonal profiles acquired at the Krauthausen natural laboratory (Germany). The multiparameter models of viscoelastic FWI (P-and S-wave velocities, attenuation of P- and S-waves, density) show pronounced lateral variations below the profiles. The groundwater table is located at around 2 m, where a sudden P-wave velocity increase occurs. An S-wave low velocity layer exists at the depth of 4-6 m with a high Poisson’s ratio value close to 0.5, which corresponds to a saturated sand layer know from previous studies. A KK-mean cluster analysis is used to correlate and integrate information contained in the inverted results. By considering the derived Poisson’s ratio, P-wave, and S-wave velocities by FWI, we can convert the complex relationship between the multivariate data into a lithological meaningful zonation of the survey region. By comparing the lithological units in the alluvial aquifer with the cone penetration tests clusters, the face maps provide valuable information about the subsurface heterogeneity and connectivity. This experiment indicates that the multiparameter models derived by viscoelastic FWI contain usefull information for high resolution near-surface aquifer characterization

    Imaging of vertical seismic profiling data using weighted generalized radon transform migration in dip-angle domain

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    The vertical seismic profiling (VSP) acquisition technique deploys sensors down a borehole, which often goes deep into the target area. It is easy to produce serious “smile” migration artifacts near the sensors during the migration imaging process of VSP data, which contaminates the imaging profile and affects the subsequent geological interpretation. In this paper, we analyze in detail the formation of these migration artifacts during the migration of VSP data. We extend the generalized Radon transform (GRT) migration method to the dip-angle domain and then generate dip-angle domain common image gathers (DDCIGs). Meanwhile, a variant sigmoid weighting function is applied to the DDCIGs to suppress the migration artifacts. The numerical results of synthetic and field data demonstrate high-quality DDCIG images and the significant artifact suppression capability of the proposed method

    A multiphase seismic investigation of the shallow subduction zone, southern North Island, New Zealand

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    The shallow structure of the Hikurangi margin, in particular the interface between the Australian Plate and the subducting Pacific Plate, is investigated using the traveltimes of direct and converted seismic phases from local earthquakes. Mode conversions take place as upgoing energy from earthquakes in the subducted slab crosses the plate interface. These PS and SP converted arrivals are observed as intermediate phases between the direct P and S waves. They place an additional constraint on the depth of the interface and enable the topography of the subducted plate to be mapped across the region. 301 suitable earthquakes were recorded by the Leeds (Tararua) broad-band seismic array, a temporary line of three-component short-period stations, and the permanent stations of the New Zealand national network. This provided coverage across the land area of southern North Island, New Zealand, at a total of 17 stations. Rays are traced through a structure parametrized using layered B-splines and the traveltime residuals inverted, simultaneously, for hypocentre relocation, interface depth and seismic velocity. The results are consistent with sediment in the northeast of the study region and gentle topography on the subducting plate. This study and recent tectonic reconstructions of the southwest Pacific suggest that the subducting plate consists of captured, oceanic crust. The anomalous nature of this crust partly accounts for the unusual features of the Hikurangi margin, e.g. the shallow trench, in comparison with the subducting margin further north

    Clinical analysis of transurethral holmium laser enucleation in the treatment of benign prostatic hyperplasia with prostatic inflammation: A prospective research study

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    ObjectiveTo investigate the clinical efficacy of holmium laser enucleation of the prostate (HoLEP) in the treatment of benign prostatic hyperplasia (BPH) with prostatic inflammation (PI).MethodsWe prospectively collected and followed up data on patients with BPH who underwent HoLEP at the Affiliated Hospital of Weifang Medical University between July 2021 and July 2022. According to the postoperative pathological results, the patients were divided into two groups: BPH without PI group (BPH group) and BPH with PI group. Statistical analysis was performed on clinical data, including age and body mass index (BMI), prostate volume (PV), postoperative residual urine volume (PVR), preoperative serum total prostate-specific antigen (tPSA), serum-free prostate-specific antigen (fPSA), preoperative and postoperative maximum urinary flow rate (Qmax), International Prostate Symptom Score (IPSS) before and 3 months after surgery, quality of life index (QoL) before and 3 months after surgery, and postoperative complications.ResultsA total of 41 patients were included in this study, including 16 in the BPH group and 25 in the BPH with PI group. There were no significant differences in preoperative age, BMI, PV, PVR, tPSA, fPSA, and f/tPSA between the BPH and BPH with PI groups (P > 0.05). The preoperative mean Qmax of the BPH and BPH with PI groups were 9.44 ± 2.449 and 7.52 ± 2.946 [mean ± standard deviation (SD)] ml/s, mean IPSS were 17.75 ± 5.335 and 24.24 ± 5.861 (mean ± SD), and mean QoL were 4.13 ± 0.806 and 4.48 ± 0.8 (mean ± SD), respectively. The postoperative mean Qmax of the BPH and BPH with PI groups were 20.38 ± 4.787 and 14.32 ± 3.827 (mean ± SD) ml/s, mean IPSS were 2.69 ± 1.25 and 5.84 ± 3.579 (mean ± SD), and mean QoL were 0.13 ± 0.342 and 0.92 ± 0.759 (mean ± SD), respectively. In both groups, Qmax significantly increased (P < 0.05) and IPSS and QoL significantly decreased after HoLEP (P < 0.05). Before and after surgery, the Qmax in the BPH with PI group was lower than that in the BPH group, and the IPSS and QoL levels in the BPH with PI group were higher than those in the BPH group (P < 0.05). Compared with the BPH group, the increase in Qmax in the BPH with PI group was smaller and the decrease in IPSS was larger (P < 0.05), but the variation in QoL was not statistically significant (P > 0.05).ConclusionImprovements in Qmax, IPSS, and QoL in BPH patients with PI after HoLEP surgery were lower than those in BPH patients alone. PI may be a predictor of a worse response to surgical treatment. However, more multicenter randomized controlled trials with larger samples and long-term follow-up are needed to verify this

    Room-temperature structure, magnetic, and magnetocaloric properties of (La0.8-xNdx)Sr0.2MnO3(0 ≤ x ≤ 0.2)

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    In this study, the impacts of Nd doping on the structural, morphological, magnetic, and magnetocaloric properties of (La0.8-xNdx)Sr0.2MnO3 (0 ≤ x ≤ 0.2) (LNSMO) have been investigated. LNSMO has been synthesized using the sol-gel technique (SG). XRD analysis revealed that LNSMO has a rhombohedral structure and belongs to the R-3c space group (No. 167). In addition, the XRD refinement using Fullprof software demonstrated that the cell volume and lattice parameters gradually reduced as Nd doping increased, confirming the gradual replacement of the La sites by Nd. The fitting of the Mn 2p peak by X-ray photoelectron spectroscopy (XPS) confirmed that Mn is in mixed valence (Mn3+, Mn4+), which contributes to the double exchange interactions (DE). It is confirmed by M−H that the paramagnetic (PM) - ferromagnetic (FM) transition of LNSMO is a second-order magnetic phase transition. There is a significant change in the magnetocaloric effect (MCE) around room temperature. The results of the magnetization measurements indicate that a reduction in the Curie temperature (Tc) and an increase in the Nd doping cause an increase followed by a decrease in the maximum magnetic entropy change (-ΔSMmax). On the contrary, the relative cooling power (RCP) first decreases and then increases. Therefore, we propose La0.62Nd0.18Sr0.2MnO3 sample with Tc = 300 K, -ΔSMmax = 4.22 J/(kg·K) and RCP = 253.39 (J/kg) under an external magnetic field. This material is potentially one of the candidates that could be used to develop magnetic refrigeration technology
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