Ca
2+
has been considered as a necessary ion for alleviation of stress-induced damages in plants. We investigated effects of exogenous Ca
2+
on waterlogging-induced damage to pepper and its ...underlying mechanisms. Pepper seedlings under stress were treated by spraying of 10 mM CaCl
2
. Applying exogenous Ca
2+
increased the biomass of pepper leaves and roots, improved photosynthetic characteristics, membrane permeability, root activity, osmotic substance contents, antioxidant enzyme and alcohol dehydrogenase activities, while it reduced lactate dehydrogenase activity. It maintained hydroxide radical contents and activities of malate dehydrogenase and succinate dehydrogenase relatively high. Our results suggested that applying exogenous Ca
2+
could regulate osmotic substance contents, antioxidant system activity, root respiration, and metabolism, and subsequently alleviate waterlogging-induced damages to pepper plants.
The theory and application of fiber Bragg grating sensors are studied in this paper. The three-directional metallized fiber Bragg grating strain sensor with temperature compensation has been ...developed. The Metallization Technology of fiber grating is studied. The Metallization Technology Scheme of fiber grating is discussed in detail. The electroless composite nickel-plating process and the formula of nickel-plating process are given. A metal fiber grating strain sensor with temperature compensation is developed. The metal fiber grating sensor is fixed to the substrate by laser welding, and a one-way metal fiber grating strain sensor with temperature compensation is formed. Three unidirectional metallized fiber Bragg grating strain sensors are connected with the developed common welding blocks to form a three-directional strain flower. Comparing with resistance strain rosette stress test and its application in ship structure stress monitoring, the fiber grating strain sensor developed in this paper fully meets the requirements of large-scale structure long-term strain monitoring.
HW Vir-like close binaries are thought to be the progenitors of cataclysmic variables. However, how this type of peculiar stars evolve into cataclysmic variables is an unsolved problem in ...astrophysics. Here we report the variations of the orbital period of HW Vir, the prototype of this group of systems. A long-term period decrease is discovered to be superimposed on the well-known cyclic change reported by previous investigators. It is suggested that the continuous decrease can be plausibly interpreted by angular momentum loss via magnetic braking of the completely convective star. This is driving the shrink of the orbit and will result in mass transfer between both components. We found that the binary will be undergoing mass transfer long before the sdB primary star evolves into a white dwarf. This conclusion suggests that HW Vir-like binaries do not directly evolve into cataclysmic variables through angular momentum loss as astronomers previously thought. On the other hand, if the observed period decrease is only part of a long-period cyclic variation, it may reveal the presence of another substellar companion in a wide orbit. This makes HW Vir an important system for future study of the formation and evolution of substellar objects.
The carbon fiber reinforced silicon carbide matrix (C/SiC) composites were prepared by using precursor infiltration and pyrolysis method. Fracture characteristics of C/SiC materials were studied by ...single edge notched beam with the aid of digital image correlation (DIC) technique. It was found that DIC played an important role in in-situ monitoring full/local strain evolution and cracking growth during bending tests, which was useful for revealing potential failure micro-mechanisms of C/SiC composites. The results showed that the average fracture toughness KIC and fracture strength of C/SiC were estimated as 7.81±0.12MPam1/2 and 223.23±3.5MPa, respectively. Moreover, the crack extension resistance curves (R-curve) in terms of stress intensity (KR-curves) were determined on the basis of the crack initiation toughness KIC. The values varied from 4.68MPam1/2 to 16.83MPam1/2 during the R-curve tests.
To evaluate the possible mediation effect of smoking and healthy diet score on the association between educational level and the risk of lung cancer incidence.
After excluding individuals with ...missing educational levels and cancer information at baseline, 446 772 participants in the UK Biobank (UKB) prospective cohort study were included. Cox regression models were used to investigate the associations of educational level and smoking and healthy diet score with the incidence of lung cancer. Mediating effect analysis was conducted to analyze the mediating effect of smoking and healthy diet score on the correlation between educational level and lung cancer.
During a median follow-up of 7.13 years, 1 994 new- onset lung cancer cases were observed. Per 1 standard deviation (5 years) increase in educational level was associated with a 12% lower risk of lung cancer (
=0.88, 95%
: 0.84-0.92). The corresponding level 1-5 in the International Standard Classification for Education (ISCED) were mapped to UKB self-report
Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory ...(LHAASO) of the bright GRB 221009A, which serendipitously occurred within the instrument's field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger and then rose to a peak ~10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle of ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.
In order to improve the particle identification capability, the Beijing Spectrometer (BESIII) collaboration has upgraded the End-cap Time-Of-Flight detector (ETOF) based on Multi-gap Resistive Plate ...Chamber (MRPC) technology. In this paper, the design and engineering development of each part of the project are reported. There are 72 MRPC modules, forming 2 rings. Adjacent modules are staggered placed to avoid dead regions. Each MRPC module contains 12-layer thin gaps to get fast signals with high efficiency and 12 strips to readout the induced signals from two ends, effectively reducing the timing uncertainties from the scattering and positioning. Also, the analog–digital conversion is done near the MRPC and only the digital signals are transferred through thin coax cables, ensuring good signal-to-noise ratio. The complex electromagnetic noises in the BESIII colliding area are well shielded to protect the tiny signals from the MRPC. After careful correction and calibration, the total time resolution of upgraded ETOF system is 65ps.
PDF
