Low Frequency Quasi-periodic Oscillation in MAXI J1820+070: Revealing distinct Compton and Reflection Contributions

X-ray low frequency quasi-periodic oscillations (LFQPOs) of black hole X-ray binaries, especially those type-C LFQPOs, are representative timing signals of black hole low/hard state and intermediate state, which has been suspected as to originate due to Lense-Thirring precession of the accretion flow. Here we report an analysis of one of the \emph{Insight}-HXMT observations of the black hole transient MAXI J1820$+$070 taken near the flux peak of its hard spectral state during which strong type-C LFQPOs were detected in all three instruments up to photon energies above 150 keV. We obtained and analyzed the short-timescale X-ray spectra corresponding to high- and low-intensity phases of the observed LFQPO waveform with a spectral model composed of Comptonization and disk reflection components. We found that the normalization of the spectral model is the primary parameter that varied between the low and high-intensity phases. The variation in the LFQPO flux at the hard X-ray band (> 100 keV) is from the Compton component alone, while the energy-dependent variation in the LFQPO flux at lower energies (< 30 keV) is mainly caused by the reflection component with a large reflection fraction in response to the incident Compton component. The observed X-ray LFQPOs thus should be understood as manifesting the original timing signals or beats in the hard Compton component, which gives rise to additional variability in softer energies due to disk reflection.Comment: 8 pages, 4 figures, accepted for publication in MNRA

ηQ\eta_{Q} meson photoproduction in ultrarelativistic heavy ion collisions

The transverse momentum distributions for inclusive $\eta_{c,b}$ meson described by gluon-gluon interactions from photoproduction processes in relativistic heavy ion collisions are calculated. We considered the color singlet (CS) and color octet (CO) components with the framework of non-relativistic Quantum Chromodynamics (NRQCD) into the production of heavy quarkonium. The phenomenological values of the matrix elements for the color-singlet and color-octet components give the main contribution to the production of heavy quarkonium from the gluon-gluon interaction caused by the emission of additional gluon in the initial state. The numerical results indicate that the contribution of photoproduction processes cannot be negligible for mid-rapidity in p-p and Pb-Pb collisions at the Large Hadron Collider (LHC) energies.Comment: 11 pages, 2 figure

Modification of slope stability probability classification and its application to rock slopes in hydropower engineering regions

Stability assessment of rock slopes in hydropower engineering regions is an important and complex issue. Rock mass classification systems are a good approach because they thoroughly consider many factors influencing rock slope stability. The slope stability probability classification (SSPC) system is a novel method. However, it has two obvious limitations when applied to rock slopes: 1) it is only suitable for slopes less than 45 m in height, and 2) there is great subjectivity and randomness in the estimation of intact rock strength. Therefore, this study presents two modifications of the SSPC system by adopting the Hoek–Brown strength criterion and an empirical formula for maximum slope height. Evaluation of results from of 34 typical rock slopes of the major hydropower engineering regions in China indicated that the accuracy rate of the modified SSPC for stability evaluation of these slopes was 61.8%, and the accuracy for stability evaluation of 10 slopes with non-structural control failure was 80%. The stability values of stable and unstable slopes obtained using the modified SSPC were different to those obtained using the Chinese Slope Mass Rating (CSMR) and modified CSMR systems. In addition, the identification accuracy rate of the modified SSPC was significantly higher than that of the CSMR and modified CSMR. Therefore, the modified SSPC can be applied to hydropower engineering regions, providing a new means of rapidly evaluating the slope stability of high rock slopes (slopes > 45 m in height) in these regions.</p

Dual trigger for final oocyte maturation in expected normal responders with a high immature oocyte rate: a randomized controlled trial

ObjectiveTo evaluate whether dual trigger could improve reproductive outcomes in women with low oocyte maturation rates compare to human chorionic gonadotropin (hCG) trigger.MethodsThis study included expected normal ovarian responders younger than 40 years old whose immature oocyte rate in the previous cycle was more than 50% at the reproductive center from July 2021 to November 2022. A total of 73 patients were enrolled at trigger, including 34 in the hCG trigger group and 39 in the dual trigger group (co-administration of gonadotrophin releasing hormone (GnRH) agonist and hCG, 40 and 34 h prior to oocyte retrieval, respectively). The primary outcome was oocyte maturation rate.ResultsThere was no significant difference in the number of oocytes retrieved between the two study groups, but the oocyte maturation rate was higher in dual trigger group (84.0% [14.0%] vs. 55.5% [19.8%], p &lt; 0.001). Moreover, there were also higher cumulative pregnancy rate (69.4% vs. 40.0%, p = 0.035) and cumulative live birth rate (66.7% vs. 36.0%, p = 0.022) in dual trigger group.ConclusionFor normal responders with low oocyte maturation rates, the dual trigger may be more effective than the conventional hCG trigger.Clinical trial registrationClinicalTrials.gov, identifier ChiCTR2100049292

Fault-tolerant polyphase filters-based decimators for SRAM-based FPGA implementations

To reduce the oversampling rate of baseband signals, decimation is widely used in digital communication systems. Polyphase filters (PPFs) can be used to efficiently implement decimators. SRAM-based FPGAs provide large amounts of resources combined with flexibility and are a popular option for the implementation of communication receivers. However, they are sensitive to soft errors, which limit their application in harsh environments, such as space. An initial reliability study on SRAM-based FPGA implemented decimation shows that the soft errors on around 5% of the critical bits in the configuration memory of the decimator would degrade the decimated signal dramatically. Based on this result, this paper proposes an efficient fault tolerance scheme, in which the high correlation between adjacent PPFs outputs is utilized to tolerate the fault of a single-phase filter, and a duplicate and comparison structure is used to protect the fault tolerance logic. Hardware implementation and fault injection experiments show that the proposed scheme can drastically reduce the number of critical bits that cause severe output degradation with 1.5x resource usage and 0.75x maximum frequency relative to the unprotected decimator. Therefore, the proposed scheme can be an alternative to Triple Modular Redundancy that more than triples the use of resources.This work is supported by Natural Science Funds of China (Grant No. 62171313) and is partially supported by the ACHILLES project PID2019-104207RB-I00 funded by the Spanish Ministry of Science and Innovation and by the Madrid Community research project TAPIR-CM grant no. P2018/TCS-4496

Tailoring acidity of HZSM-5 nanoparticles for methyl bromide dehydrobromination by Al and Mg incorporation

Three kinds of HZSM-5 nanoparticles with different acidity were tailored by impregnating MgO or varying Si/Al ratios. Both the textural and acidic properties of the as-prepared nanoparticles were characterized by nitrogen adsorption-desorption measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature-programmed desorption (NH(3)-TPD) and Fourier transform infrared spectroscopy (FTIR or Py-FTIR). It was found that the intensity of Lewis acid sites with weak strength was enhanced by impregnating MgO or reducing Al concentration, and such an enhancement could be explained by the formation of Mg(OH)(+) or charge unbalance of the MgO framework on the surface of HZSM-5 support. The effect of HZSM-5 nanoparticles' acidity on methyl bromide dehydrobromination as catalyst was evaluated. As the results, MgHZ-360 catalyst with the highest concentration of Lewis acid sites showed excellent stability, which maintained methyl bromide conversion of up 97% in a period of 400 h on stream. Coke characterization by BET measurements and TGA/DTA and GC/MS analysis revealed that polymethylated naphthalenes species were formed outside the channels of the catalyst with higher acid intensity and higher Brønsted acid concentration during the initial period of reaction, while graphitic carbon formed in the channels of catalyst with lower acid intensity and higher Lewis acid concentration during the stable stage