130 research outputs found

    Experimental and Numerical Research on Seismic Performance of Earthquake-Damaged RC Frame Strengthened with CFRP Sheets

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    In order to assess the seismic performance of damaged reinforced concrete (RC) frame strengthened with carbon fiber reinforced polymers (CFRP) sheets, two experimental specimens with identical reinforcement ratio and geometric dimensions were designed following Chinese code for seismic design of buildings. Experimental specimens consist of a reference (undamaged) RC frame, namely, KJ-1, and an earthquake-damaged RC frame strengthened with CFRP sheets, namely, KJ-2. A pseudostatic test was conducted on the two specimens to simulate moderate earthquake damage. The strengthening effects of CFRP sheets on damaged RC frame were discussed in terms of hysteretic curve, skeleton curve, stiffness degradation, and ductility. In addition, numerical method based on fiber model method was utilized to analyze the seismic performance of KJ-1 and KJ-2 and it is compared with the experimental result. Both the results confirm that the method of exterior bonding CFRP sheets on the damaged RC frame has restored the seismic performance such as bearing capacity, stiffness, and ductility to its original undamaged level, and some of the seismic performance of the damaged RC frame strengthened with CFRP sheets is even better than the undamaged one, which proves that the method has significant effect in strengthening postearthquake-damaged RC frames

    Potential of Core-Collapse Supernova Neutrino Detection at JUNO

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    JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

    Detection of the Diffuse Supernova Neutrino Background with JUNO

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    As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

    Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

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    Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30M⊙M_{\odot} for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

    Effects of different Chinese herbal prescriptions on cytokines in autoimmune prostatitis rats

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    AbstractObjectiveTo observe and compare the effects of Chinese herbal prescriptions for promoting blood circulation, clearing heat, removing toxicity, and dispersing stagnated liver-Qi on cytokines in model rats with experimental autoimmune prostatitis (EAP) to provide an experimental basis for the use of Chinese herbal prescriptions in the treatment of chronic prostatitis.MethodsOne-hundred and ten male Wistar rats were randomly divided into 11 groups: blank group; model group; Huoxuehuayu (promoting blood circulation to remove blood stasis) high, middle, and low dose groups; Qingrejiedu (clearing heat and removing toxicity) high, middle, and low dose groups; and Shuganliqi (dispersing stagnated liver-Qi) high, middle, and low dose groups. Except the blank group, rats in all groups were injected subcutaneously in multiple points on days 0 and 30 with prostatic protein extractive solution (60 mg/mL), and intraperitoneally injected with diphtheria-pertussis and tetanus vaccine (DPT vaccine) to establish the EAP model. Model rats were administrated high, middle, and low doses of Chinese herbal prescriptions and were sacrificed after 4 weeks. Pathological changes in the prostate gland were observed with HE staining and changes in serum interleukin-6 (IL-6), interleukin-8 (IL-8), and prostaglandin E2 (PGE2) levels were detected with enzyme-linked immunosorbent assay.ResultsCompared with the blank group, serum PGE2, IL-6, and IL-8 levels in the model group were significantly higher (P < 0.05). Compared with the model group, serum PGE2, IL-6, and IL-8 levels in the Qingrejiedu low dose and middle dose groups were significantly lower (P < 0.05), with the lower dose having a more obvious effect. Serum PGE2, IL-6, and IL-8 levels in the Huoxuehuayu high dose group (P < 0.05), IL-6 and IL-8 levels in the Huoxuehuayu middle dose group (P < 0.05), and the IL-8 level in the Huoxuehuayu low dose group were significantly lower than those in the model group (P < 0.05). There were significant differences in PGE2 and IL-6 levels among the different dose groups of Shuganliqi drugs (P < 0.05). Compared with the model group, serum PGE2, IL-6, and IL-8 levels in the Shuganliqi high dose group (P < 0.05) and IL-8 level in the Shuganliqi low dose group were significantly lower (P < 0.05), while the Shuganliqi middle dose group did not change significantly (P > 0.05).ConclusionTherefore, in TCM treatment of autoimmune prostatitis, different treatment methods should select different doses. For prescriptions that clear heat and remove toxicity, low doses should be used. For prescriptions that promote blood circulation to remove blood stasis and for prescriptions that disperse stagnated liver-Qi, high doses should be used

    Noninvasive right ventricular work in patients with atrial septal defects: a proof-of-concept study

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    Abstract Background Noninvasive right ventricular (RV) myocardial work (RVMW) determined by echocardiography is a novel indicator used to estimate RV systolic function. To date, the feasibility of using RVMW has not been verified in assessing RV function in patients with atrial septal defect (ASD). Methods Noninvasive RVMW was analysed in 29 ASD patients (median age, 49 years; 21% male) and 29 age- and sex-matched individuals without cardiovascular disease. The ASD patients underwent echocardiography and right heart catheterization (RHC) within 24 h. Results The RV global work index (RVGWI), RV global constructive work (RVGCW), and RV global wasted work (RVGWW) were significantly higher in the ASD patients than in the controls, while there was no significant difference in RV global work efficiency (RVGWE). RV global longitudinal strain (RV GLS), RVGWI, RVGCW, and RVGWW demonstrated significant correlations with RHC-derived stroke volume (SV) and SV index. The RVGWI (area under receiver operating characteristic curve [AUC] = 0.895), RVGCW (AUC = 0.922), and RVGWW (AUC = 0.870) could be considered good predictors of ASD and were superior to RV GLS (AUC = 0.656). Conclusion The RVGWI, RVGCW, and RVGWW could be used to assess RV systolic function and are correlated with RHC-derived SV and SV index in patients with ASD. Graphical Abstrac
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