A schematic drawing showingthe optimization of cut blasting design in the condition of vertical stress at 70MPa and horizontal stress at 30MPa.
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•The parameters of RHT model applicable ...to modeling the damage evolution of rock are determined.•The causes for the difficulty in the excavation of deep rock mass arestudied.•The method to the optimization of cut blasting design under high in-situ stresses is proposed.
During excavation using the cut blasting method in deep rock masses, there are difficulties resulting from the in-situ stress influences. This study uses numerical simulation methods to assess the causes of the difficulties encountered in cut blasting. In order to overcome this difficulty, the Riedel–Hiermaier–Thoma (RHT) model in the LS-DYNA software was employed. In the simulation, the parameter determination for the RHT model was first carried out based on existing experimental data. Additionally, the existing blasting experiment was used to verify the determined parameters of RHT model. Second, the RHT model was adopted to investigate the damage mechanisms of cut blasting under different hydrostatic pressures and different lateral pressure coefficients. The simulation results indicate that the main causes of the complications arising in deep rock mass excavation are resistance to in-situ stresses and anisotropy in the damage propagation direction. Third, in order to overcome such difficulties, a cut blasting design optimization was conducted for a 2525m depth of rock mass. According to the numerical simulation of this optimization, a modified cut blasting design method applicable to deep rock mass was proposed. This study can provide solutions to the cut blasting difficulties that are encountered during the excavation of deep rock masses.
We present a three-dimensional extinction map in the r band. The map has a spatial angular resolution, depending on latitude, between 3 and 9 arcmin and covers the entire Xuyi Schmidt Telescope ...Photometric Survey of the Galactic Anticentre (XSTPS-GAC) survey area of over 6000 deg2 for Galactic longitude 140 < l < 240 deg and latitude −60 < b < 40 deg. By cross-matching the photometric catalogue of the XSTPS-GAC with those of 2MASS and WISE, we have built a multiband photometric stellar sample of about 30 million stars and applied spectral energy distribution (SED) fitting to the sample. By combining photometric data from the optical to the near-infrared, we are able to break the degeneracy between the intrinsic stellar colours and the amounts of extinction by dust grains for stars with high photometric accuracy, and trace the extinction as a function of distance for low Galactic latitude and thus highly extincted regions. This has allowed us to derive the best-fitting extinction and distance information of more than 13 million stars, which are used to construct the three-dimensional extinction map. We have also applied a Rayleigh–Jeans colour excess (RJCE) method to the data using the 2MASS and WISE colour (H − W2). The resulting RJCE extinction map is consistent with the integrated two-dimensional map deduced using the best-fitting SED algorithm. However for individual stars, the amounts of extinction yielded by the RJCE method suffer from larger errors than those given by the best-fitting SED algorithm.
•Full-field strain and strain-rate fields of rock was obtained by high-speed 3D-DIC.•The 256 × 256 pixels and 200,000 fps are suggested in dynamic measurement of rock.•Wave propagation, dispersion ...and radial inertial effect on the specimen were found.•The comparison was conducted between 2D- and 3D-DIC in strain measurement.•The failure of sandstone is a shear mode in the test of split Hopkinson pressure bar.
Full-field strain and strain-rate fields of rock materials under dynamic compression were studied by the high-speed three-dimensional digital image correlation (3D-DIC) method. A series of dynamic tests was conducted on Hawkesbury sandstones using a split Hopkinson pressure bar (SHPB) at three different strain rates. The real-time images of the loaded specimen were captured by two high-speed cameras at a frame rate of 200,000 frames per second (fps) with a resolution of 256 × 256 pixels. Wave propagation, dispersion and radial inertial effect on the specimen were found by DIC results. The strain rate vibration pattern on the specimen, which was visualised by DIC, found to be dependent on the input waveform. A recovery of strain in the post-peak stage was detected on the specimen by DIC, which is unrevealed in the traditional one-dimensional theory method (i.e., strain gauge signals). The results showed that strain localisation initiated from the interface of the bar and specimen with the order of tensile, shear and vertical. The initiation of crack from strain localisation is found rate-independent. Comparison between 2D- and 3D-DIC in strain measurement of the same experiment showed that the error in the strain obtained by 2D-DIC could be up to 32%.
ABSTRACT
The High Energy (HE) X-ray telescope on board the Hard X-ray Modulation Telescope (Insight-HXMT) can serve as a wide field of view (FOV) gamma-ray monitor with high time resolution (μs) and ...large effective area (up to thousands cm2). We developed a pipeline to search for gamma-ray bursts (GRBs), using the traditional signal-to-noise ratio (SNR) method for blind search and the coherent search method for targeted search. By taking into account the location and spectrum of the burst and the detector response, the targeted coherent search is more powerful to unveil weak and sub-threshold bursts, especially those in temporal coincidence with gravitational wave (GW) events. Based on the original method in literature, we further improved the coherent search to filter out false triggers caused by spikes in light curves, which are commonly seen in gamma-ray instruments (e.g. Fermi/GBM, POLAR). We show that our improved targeted coherent search method could eliminate almost all false triggers caused by spikes. Based on the first two years of Insight-HXMT/HE data, our targeted search recovered 40 GRBs, which were detected by either Swift/BAT or Fermi/GBM but too weak to be found in our blind search. With this coherent search pipeline, the GRB detection sensitivity of Insight-HXMT/HE is increased to about 1.5E-08 erg cm−2 (200 keV–3 MeV). We also used this targeted coherent method to search Insight-HXMT/HE data for electromagnetic counterparts of LIGO-Virgo GW events (including O2 and O3a runs). However, we did not find any significant burst associated with GW events.
Abstract Background/aims The role of high mobility group box chromosomal protein 1 in hepatocellular carcinoma is unknown. The aim of study was to evaluate contributions of high mobility group box ...chromosomal protein 1 in hepatocellular carcinoma, and analyse the correlation between high mobility group box chromosomal protein 1 and clinicopathologic outcomes. Patients/methods High mobility group box chromosomal protein 1 levels were analysed by Western blot analysis. Edmondson grade, TNM stage and the Cancer of the Liver Italian Program score were used as analysis variables. Results The serum high mobility group box chromosomal protein 1 levels in hepatocellular carcinoma (84.2 ± 50.4 ng/ml) was significantly higher than those in chronic hepatitis (39.8 ± 10.5 ng/ml), liver cirrhosis (40.2 ± 11.6 ng/ml) and healthy control (7.0 ± 5.9 ng/ml, p < 0.0001, respectively), and positive correlation were found between high mobility group box chromosomal protein 1 and α-fetoprotein ( r = 0.952, p < 0.0001), and between high mobility group box chromosomal protein 1 and the size of tumour ( r = 0.904, p < 0.0001). High mobility group box chromosomal protein 1 were significant differences among Edmondson grade I, II, III, IV; TNM stage I, II, III, IV and Cancer of the Liver Italian Program score 0–1 points, 2–4 points, >4 points ( p < 0.0001, respectively). Conclusions These results suggest that high mobility group box chromosomal protein 1 may be a useful marker for evaluating the tumour stage and predicting prognosis in hepatocellular carcinoma. Targeting high mobility group box chromosomal protein 1 production or release might have potential approaches for hepatocellular carcinoma treatment.
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease that was caused by a novel bunyavirus, SFTSV. The study aimed to disclose the epidemiological and clinical ...characteristics of SFTSV infection in China so far. An integrated clinical database comprising 1920 SFTS patients was constructed by combining first-hand clinical information collected from SFTS sentinel hospitals (n = 1159) and extracted data (n = 761) from published literature. The considered variables comprised clinical manifestations, routine laboratory tests of acute infection, hospitalization duration and disease outcome. SFTSV-IgG data from 19 119 healthy subjects were extracted from the published papers. The key clinical variables, case-fatality rate (CFR) and seroprevalence were estimated by meta-analysis. The most commonly seen clinical manifestations of SFTSV infection were fever, anorexia, myalgia, chill and lymphadenopathy. The major laboratory findings were elevated lactate dehydrogenase, aminotransferase, followed by thrombocytopenia, lymphocytopenia, elevated alanine transaminase and creatine kinase. A CFR of 12·2% was estimated, significantly higher than that obtained from national reporting data, but showing no geographical difference. In our paper, the mortality rate was about 1·9 parts per million. Older age and longer delay to hospitalization were significantly associated with fatal outcome. A pooled seroprevalence of 3·0% was obtained, which increased with age, while comparable for gender. This study represents a clinical characterization on the largest group of SFTS patients up to now. A higher than expected CFR was obtained. A wider spectrum of clinical index was suggested to be used to identify SFTSV infection, while the useful predictor for fatal outcome was found to be restricted.
This Letter reports reliable satellite data in the period of 1980-2007 covering two full 11-yr cosmic ray (CR) cycles, clearly showing the correlation between CRs and ozone depletion, especially the ...polar ozone loss (hole) over Antarctica. The results provide strong evidence of the physical mechanism that the CR-driven electron-induced reaction of halogenated molecules plays the dominant role in causing the ozone hole. Moreover, this mechanism predicts one of the severest ozone losses in 2008-2009 and probably another large hole around 2019-2020, according to the 11-yr CR cycle.
Hysteresis underlies a large number of phase transitions in solids, giving rise to exotic metastable states that are otherwise inaccessible. Here, we report an unconventional hysteretic transition in ...a quasi-2D material, EuTe_{4}. By combining transport, photoemission, diffraction, and x-ray absorption measurements, we observe that the hysteresis loop has a temperature width of more than 400 K, setting a record among crystalline solids. The transition has an origin distinct from known mechanisms, lying entirely within the incommensurate charge density wave (CDW) phase of EuTe_{4} with no change in the CDW modulation periodicity. We interpret the hysteresis as an unusual switching of the relative CDW phases in different layers, a phenomenon unique to quasi-2D compounds that is not present in either purely 2D or strongly coupled 3D systems. Our findings challenge the established theories on metastable states in density wave systems, pushing the boundary of understanding hysteretic transitions in a broken-symmetry state.
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