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Abstract. The determination of rockfall impact force is crucial in designing protection measures. In the present study, laboratory tests are carried out by testing the weight and shape of the falling rock fragments, drop height, incident angle, platform on the slideway, and cushion layer on the protection measures to investigate their influences on the impact force. The test results indicate that the impact force is positively exponential to the weight of rockfall and the instantaneous impact velocity of the rockfall approaching the protection measures. The impact velocity is found to be dominated not only by the drop height but also by the shape of rockfall and the length of the platform on the slideway. A great drop height and/or a short platform produces a fast impact velocity. Spherical rockfalls experience a greater impact velocity than cubes and elongated cuboids. A layer of cushion on the protection measures may reduce the impact force to a greater extent. The reduction effects are dominated by the cushion material and the thickness of the cushion layer. The thicker the cushion layer, the greater the reduction effect and the less the impact force. The stiffer the buffer material, the lower the buffering effect and the greater the impact force. The present study indicates that the current standard in China for designing protection measures may overestimate the impact force by not taking into consideration the rockfall shape, platform, and cushion layer.

In this study, Eudragit S-100 has been covalently bound to the cellulase enzyme to form immobilized cellulase enzyme and then the effect of the treatment on ramie fabric properties is studied. The ramie fabrics treated with immobilized cellulase enzyme show lower quantities of reducing sugar, weight loss, and higher tensile strength than native cellulase enzyme-treated fabrics. Scanning electron microscopic analysis shows that the surface of ramie fabrics treated with cellulase enzyme is smoother than that of the untreated sample. Furthermore, treatment by the immobilized cellulase enzyme is less damaging to the fibres. X-ray diffraction studies show that there is hardly any loss in the crystallinity of ramie fabrics. Low-stress mechanical properties evaluated by the Kawabata Evaluation System for Fabric indicate that immobilized cellulase enzyme treatment improves the softness, flexibility, and elastic recovery of the ramie fabrics. ; This work was funded by the Galician government (Xunta de Galiza) through the I2C postdoctoral program (fellowship ED481B2014/133-0), and by the Spanish Ministry of Economy and Competitiveness (grant ...

The electrical transport properties of (Li,Fe)OHFeSe films have been investigated in detail. The sharply textured films, prepared by matrix-assisted hydrothermal epitaxy (MHE) on LaAlO3, show a zero-resistance critical temperature T c of ∼42 K, J c values well above 1 MA cm-2 at low temperatures, and a maximum pinning force density F P of ∼100 GN m-3 at 4 K. The activation energy U 0 for thermal depinning of flux lines has been resolved for low magnetic fields, it agrees well with literature data. The coherence lengths and penetration depth were estimated via upper critical field B c2 and self-field J c, respectively, to be ξ ab ∼ 2.7 nm, ξ c = 0.24 nm, and λ ab ∼ 160-200 nm. The layered crystal structure leads to highly anisotropic and two-dimensional electrical properties, including trapping and lock-in of vortices. © 2020 The Author(s). Published by IOP Publishing Ltd. ; Original content from this work may be used under the terms of the . Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. National Key Research and Development Program of China 2017YFA0303003 2016YFA0300300 Strategic Priority Research Program and Key Research Program of Frontier Sciences of the Chi-nese Academy of Sciences QYZDY-SSW-SLH001 XDB25000000 state assignment of Minobrnauki of Russia Act 211 Government of the Russian Federation 02.A03.21.0006 National Natural Science Foundation of China 11888101 11834016.

Aims. We aim to reveal the physical properties and chemical composition of the cores in the California molecular cloud (CMC), so as to better understand the initial conditions of star formation. Methods. We made a high-resolution column density map (18.2′′) with Herschel data, and extracted a complete sample of the cores in the CMC with the fellwalker algorithm. We performed new single-pointing observations of molecular lines near 90 GHz with the IRAM 30m telescope along the main filament of the CMC. In addition, we also performed a numerical modeling of chemical evolution for the cores under the physical conditions. Results. We extracted 300 cores, of which 33 are protostellar and 267 are starless cores. About 51% (137 of 267) of the starless cores are prestellar cores. Three cores have the potential to evolve into high-mass stars. The prestellar core mass function (CMF) can be well fit by a log-normal form. The high-mass end of the prestellar CMF shows a power-law form with an index α = -0.9 ± 0.1 that is shallower than that of the Galactic field stellar mass function. Combining the mass transformation efficiency (ϵ) from the prestellar core to the star of 15 ± 1% and the core formation efficiency (CFE) of 5.5%, we suggest an overall star formation efficiency of about 1% in the CMC. In the single-pointing observations with the IRAM 30m telescope, we find that 6 cores show blue-skewed profile, while 4 cores show red-skewed profile. [HCO + ]/[HNC] and [HCO + ]/[N 2 H + ] in protostellar cores are higher than those in prestellar cores; this can be used as chemical clocks. The best-fit chemical age of the cores with line observations is ~5 × 10 4 yr. © ESO 2018. ; Chinese Government Scholarship: 201804910583 ; 2017YFA0402600, 2017YFA0402702 ; Russian Science Foundation, RSF: 18-12-00351 ; Deutsche Forschungsgemeinschaft, DFG: WA3628-1/1 ; National Basic Research Program of China (973 Program): 2015CB857101 ; National Natural Science Foundation of China, NSFC: 11763002, U1431111, 11721303, 11703040, 11703074 ; Acknowledgements. We acknowledge valuable comments from the referee. We thank Charles J. Lada for useful discussion on the manuscript. We thank A. Men'shchikov, D. S. Berry, and S. Bardeau for their technical support with Getsources, Starlink and Gildas, respectively. This work is supported by National Key R&D Program of China (No. 2017YFA0402600; 2017YFA0402702), National Key Basic Research Program of China (973 Program) (No. 2015CB857101), National Natural Science foundation of China (No. 11703040; 11703074; 11721303; 11763002; U1431111), and Chinese Government Scholarship (No. 201804910583). D.A.S. acknowledges support from the Heidelberg Institute of Theoretical Studies for the project "Chemical kinetics models and visualization tools: Bridging biology and astronomy". A.I.V. acknowledges support by the Russian Science Foundation (No. 18-12-00351). K.W. acknowledges support by the German Research Foundation (grant WA3628-1/1).

The physical and chemical properties of cold and dense molecular clouds are key to understanding how stars form. Using the IRAM 30 m and NRO 45 m telescopes, we carried out a Multiwavelength line-Imaging survey of the 70 μm-dArk and bright clOuds (MIAO). At a linear resolution of 0.1-0.5 pc, this work presents a detailed study of parsec-scale CO depletion and HCO+ deuterium (D-) fractionation toward four sources (G11.38+0.81, G15.22-0.43, G14.49-0.13, and G34.74-0.12) included in our full sample. In each source with T < 20 K and nH ∼ 104-105 cm-3, we compared pairs of neighboring 70 μm bright and dark clumps and found that (1) the H2 column density and dust temperature of each source show strong spatial anticorrelation; (2) the spatial distribution of CO isotopologue lines and dense gas tracers, such as 1-0 lines of H13CO+ and DCO+, are anticorrelated; (3) the abundance ratio between C18O and DCO+ shows a strong correlation with the source temperature; (4) both the C18O depletion factor and D-fraction of HCO+ show a robust decrease from younger clumps to more evolved clumps by a factor of more than 3; and (5) preliminary chemical modeling indicates that chemical ages of our sources are ∼8 × 104 yr, which is comparable to their free-fall timescales and smaller than their contraction timescales, indicating that our sources are likely dynamically and chemically young. ; With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)