Energy-driven mechanism of failure and instability of anchored surrounding rock in deep gob-side entry

Affected by the dynamic load induced by the fracture of lateral roof in the deep gob-side entry, the anchored surrounding rock is prone to produce large deformation, even failure and instability. Taking the tailgate of the 31120 working face in the Suncun Coal Mine as an engineering background, firstly, the development law of cracks in the anchored roof and the main failure mode of brittle tension crack were obtained by using the YTJ20 rock detection recorder. In addition, based on the similar material simulation test, the typical characteristics of three stages of lateral roof movement in the deep gob-side entry were obtained, and the fracture evolution and energy release law of anchored surrounding rock in different stages were analyzed. It is noted that the internal stress and deformation of anchored surrounding rock increase sharply, the cracks develop obviously and the energy is released significantly in the transitional movement stage, which has the greatest influence on the stability of anchored surrounding rock in the gob-side entry. Finally, the structural mechanical model of gob-side entry under lateral roof fracture movement was constructed, the quantitative calculation method of input and resistant energy of anchored surrounding rock were firstly provided, the energy-driven mechanism of failure and instability was revealed, and the instability energy criterion was defined, that is, when the energy applying on anchoring surrounding rock in gob-side entry is greater than the resistant energy of anchoring surrounding rock, the instability will occur. Accordingly, the instability risk classification method of anchoring surrounding rock and the corresponding strengthening control technology were put forward. The calculation results show that the instability risk level of anchored surrounding rock in the gob-side entry of the 31120 working face was medium risk. After strengthening the support, the deformation of roof and floor and the two sides of gob-side entry were reduced by 35.47% and 35.71%, respectively, the force of anchor cable was reduced by 23.43%, the deformation speed was obviously reduced, and the energy accumulation degree of anchoring surrounding rock was reduced

An Improved 3D Ultra-Wideband High-Efficiency Substrate Integrated Coaxial Meander Delay Line

This paper proposes an improved substrate integrated coaxial meander delay line to overcome the beam dispersion problem in a spaceborne synthetic aperture radar phased array antenna system with large bandwidth. The delay line operates in the range of 4 GHz–10 GHz with a relative bandwidth of 85.7%. In the proposed structure, the delay effect is generated by the combination of a meander delay line and a substrate integrated coaxial line, which results in a significant improvement in the delay efficiency. Furthermore, a planar turn structure, a vertical transition structure, and a microstrip transition structure are designed to realize three-dimensional tight wiring. The proposed delay lines are fabricated on three and five layered Rogers RO3006 PCB substrate. The experimental tests are conducted on the 3.1 ns and 6.4 ns delay lines with the dimensions of 38 mm × 7 mm × 0.5 mm and 37 mm × 9.2 mm × 1 mm, respectively. The experimental results indicate that the insertion and return losses of the two lines are within the reasonable range. Compared with the related research, the proposed delay lines’ delay time, delay multiplier, and relative bandwidth are improved by 2.13–160 times, 1.025–6.8 times, and 2.14–3.86 times, respectively, which shows their good practical value and application prospect

Correction: Zhang, H.; Wang, P. An Improved 3D Ultra-Wideband High-Efficiency Substrate Integrated Coaxial Meander Delay Line. <i>Electronics</i> 2022, <i>11</i>, 3869

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Skill of isotope-enabled climate models for daily surface water vapour in East Asia

International audienceThe isotope-enabled general circulation models (GCM) have been widely applied to simulate the variability of stable isotopes in meteoric water at various time scales. The in-situ observations of water vapour isotopes are an important basis for assessing the performance of isotope-enabled GCMs, although they are still limited. Here we compiled the observations of near-surface water vapour isotopes on a daily scale at 17 stations in East Asia, and assessed the skill and the association between isotope error and meteorological errors on a daily scale. Generally, the spatial pattern and seasonal variability can be well simulated in the isotope-enabled GCMs. The models show better skill for warm and humid backgrounds, which also corresponds to the monsoonal regions with lower latitudes in East Asia. As spatial resolution is finer, the skill of models is better, which can be seen from the two GCMs. According to the correlation coefficient, the improvement of resolution is more obvious in summer than in winter, especially for IsoGSM. In addition, the correlation coefficient in winter is usually larger than that in summer. The daily modelling has good potential to investigate the daily or synoptic climate information in water isotopes. The findings are useful for understanding the applicability of isotope-enabled models in East Asia and the climate factors influencing the skill of isotope-enabled models on a daily basis

JMJD6 is a tumorigenic factor and therapeutic target in neuroblastoma

Chromosome 17q21-ter is commonly gained in neuroblastoma, but it is unclear which gene in the region is important for tumorigenesis. The JMJD6 gene at 17q21-ter activates gene transcription. Here we show that JMJD6 forms protein complexes with N-Myc and BRD4, and is important for E2F2, N-Myc and c-Myc transcription. Knocking down JMJD6 reduces neuroblastoma cell proliferation and survival in vitro and tumor progression in mice, and high levels of JMJD6 expression in human neuroblastoma tissues independently predict poor patient prognosis. In addition, JMJD6 gene is associated with transcriptional super-enhancers. Combination therapy with the CDK7/super-enhancer inhibitor THZ1 and the histone deacetylase inhibitor panobinostat synergistically reduces JMJD6, E2F2, N-Myc, c-Myc expression, induces apoptosis in vitro and leads to neuroblastoma tumor regression in mice, which are significantly reversed by forced JMJD6 over-expression. Our findings therefore identify JMJD6 as a neuroblastoma tumorigenesis factor, and the combination therapy as a treatment strategy

Observation of Several Sources of CPCP Violation in B+→π+π+π−B^+ \to \pi^+ \pi^+ \pi^- Decays

International audienceObservations are reported of different sources of CP violation from an amplitude analysis of B+→π+π+π- decays, based on a data sample corresponding to an integrated luminosity of 3  fb-1 of pp collisions recorded with the LHCb detector. A large CP asymmetry is observed in the decay amplitude involving the tensor f2(1270) resonance, and in addition significant CP violation is found in the π+π-S wave at low invariant mass. The presence of CP violation related to interference between the π+π-S wave and the P wave B+→ρ(770)0π+ amplitude is also established; this causes large local asymmetries but cancels when integrated over the phase space of the decay. The results provide both qualitative and quantitative new insights into CP -violation effects in hadronic B decays

First Observation of the Radiative Decay Λb0→Λγ\Lambda_{b}^{0} \to \Lambda \gamma

International audienceThe radiative decay Λb0→Λγ is observed for the first time using a data sample of proton-proton collisions corresponding to an integrated luminosity of 1.7  fb-1 collected by the LHCb experiment at a center-of-mass energy of 13 TeV. Its branching fraction is measured exploiting the B0→K*0γ decay as a normalization mode and is found to be B(Λb0→Λγ)=(7.1±1.5±0.6±0.7)×10-6, where the quoted uncertainties are statistical, systematic, and systematic from external inputs, respectively. This is the first observation of a radiative decay of a beauty baryon

Amplitude analysis of the B(s)0→K∗0K‾∗0B^0_{(s)} \to K^{*0} \overline{K}^{*0} decays and measurement of the branching fraction of the B0→K∗0K‾∗0B^0 \to K^{*0} \overline{K}^{*0} decay

International audienceThe ${B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0}$ and ${B}_s^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0}$ decays are studied using proton-proton collision data corresponding to an integrated luminosity of 3 fb$^{−1}$. An untagged and timeintegrated amplitude analysis of B_{( s}_{)}^{0}  → (K$^{+}$π$^{−}$)(K$^{−}$π$^{+}$) decays in two-body invariant mass regions of 150 MeV/c$^{2}$ around the K$^{∗0}$ mass is performed. A stronger longitudinal polarisation fraction in the ${B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0}$ decay, f$_{L}$ = 0.724 ± 0.051 (stat) ± 0.016 (syst), is observed as compared to f$_{L}$ = 0.240 ± 0.031 (stat) ± 0.025 (syst) in the ${B}_s^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0}$ decay. The ratio of branching fractions of the two decays is measured and used to determine $\mathrm{\mathcal{B}}\left({B}^0\to {K}^{\ast 0}{\overline{K}}^{\ast 0}\right)=\left(8.0\pm 0.9\left(\mathrm{stat}\right)\pm 0.4\left(\mathrm{syst}\right)\right)\times {10}^{-7}$

Measurement of CPCP-violating and mixing-induced observables in Bs0→ϕγB_s^0 \to \phi\gamma decays

International audienceA time-dependent analysis of the Bs0→ϕγ decay rate is performed to determine the CP -violating observables Sϕγ and Cϕγ and the mixing-induced observable AϕγΔ. The measurement is based on a sample of pp collision data recorded with the LHCb detector, corresponding to an integrated luminosity of 3  fb-1 at center-of-mass energies of 7 and 8 TeV. The measured values are Sϕγ=0.43±0.30±0.11, Cϕγ=0.11±0.29±0.11, and AϕγΔ=-0.67-0.41+0.37±0.17, where the first uncertainty is statistical and the second systematic. This is the first measurement of the observables S and C in radiative Bs0 decays. The results are consistent with the standard model predictions