摘要:
The beam-only connected reinforced concrete shear wall (BRW) is used as a reinforcing component to enhance the seismic performance of concrete-filled, double-skin steel tube (CFDST) frames. The effects of the BRW on seismic risks of CFDST frames are investigated. Three performance levels of limit states are defined and described according to the typical failure of test specimens and the existing definition of current guidance. A simplified numerical model is calibrated for CFDST frame-BRW structures, and test results validate it. Nonlinear dynamic analyses on a nine-story CFDST-BRW building are performed to investigate the effects of BRW on reducing the seismic risk of CFDST buildings. The results show that the BRW reduces the probability of collapse of the CFDST frame to 2.76% in 50 years, which can effectively reduce the probability of different degrees of damage in the service cycle of the structure. The results provide information for risk-informed decision-making on the design of CFDST frame-BRW structures.
摘要:
In this work, we present a simple and effective approach to enhance the fire safety and anti-corrosion performance of wood by forming in-situ self-assembled amphiphilic Ag-PW nanospheres (NSP) at room temperature. The morphology and acid capacity of the NSP were optimized by changing the ratio of phosphotungstic acid (HPW) and silver nitrate. The Ag-PW NSP were successfully integrated into the bulk of the wood, resulting in a durable treatment with minimal leaching. Comprehensive characterization techniques, including FTIR, XPS, XRD, SEM, TEM, and nitrogen adsorption–desorption analysis, confirmed the in-situ formation of Ag-PW NSP in the wood. The treatment exhibited low-leaching properties with only 5.89% of Ag-PW1a leaching out. The treated wood demonstrated excellent flame-retardant (FR) properties, as evidenced by a limiting oxygen index value > 28% and easy passage of the UL-94 test, with the formation of a high-density char layer. The flammable pyrolysis products released during combustion were found to be significantly altered, with a change in the depolymerization route of conversion of LGO under acid conditions to HMF, which was verified by DFT calculations. The treated wood also exhibited outstanding anti-corrosion properties, with a mass loss rate of less than 1%, compared to at least 32.3% for bare wood after the anti-white or brown-rot fungus tests. Moreover, the treated wood samples maintained their excellent FR properties even after leaching. Our study provides valuable insights for the rational design of nano-material additives for wood protection, thereby improving the usage of wood resources while mitigating health and environmental hazards.
摘要:
University-enterprise cooperation has experienced nearly 30 years of development in China, there are still a large number of failure cases in practice, and academic research often presents a unilateral situation of ‘enterprise-university’. This study starts with the bilateral matching between enterprises and universities, using data on invention patents jointly applied for by Chinese enterprises and universities from 2010 to 2020, discusses the influence of university-enterprise knowledge potential matching on the innovation performance of university-enterprise cooperation and the influence of university level and enterprise R&D investment intensity on the innovation performance of university-enterprise cooperation when the knowledge potential difference is similar. The results show that: (1) knowledge potential matching has a significant effect on the innovation performance of university-enterprise cooperation: the smaller the knowledge potential difference, the higher the innovation performance; (2) with similar knowledge potential difference, the level of the university has no significant impact on the innovation performance, and the R&D investment intensity of enterprises is positively correlated with the innovation performance of university-enterprise cooperation; (3) geographical proximity has a significant inverted U-shaped moderating effect on the relationship between knowledge potential matching and the innovation performance of university-enterprise cooperation.
通讯机构:
[Yang, DD ] C;Cent South Univ Forestry & Technol, Inst Wildlife Conservat, Changsha 410004, Peoples R China.
关键词:
bioacoustics;frogs;mark-recapture;Megophryinae;southern China
摘要:
We describe the advertisement call of the Nanling horned frog, Boulenophrys nanlingensis for the first time, based on recordings obtained from four individuals. One of these individuals, which was identified using its dorsum pattern, was recorded twice after nine months. Distinct shifts in the temporal parameters and call rate were observed from calls of the re-captured individual, which was suspected to be related to temperature and social context. However, due to the limited sample size, further research is needed to confirm these findings. We highlight the potential of mark-recapture method using dorsum pattern for studying and monitoring the Nanling horned frog and other megophyinid frogs.
摘要:
The construction of oxygen reduction reaction (ORR) electrocatalysts with well-textured structure and desirable activity remains great challenge for the complicated procedures and poor interface. Herein, inspired by sea anemones, the highly ordered Co-based carbon nanotubes electrocatalysts were elaborately assembled on wood fibers via stoichiometry. The porous cell-wall and abundant oxygen groups in lignocellulosic scaffold impose such preferable structure, in which the Co-based carbon nanotubes with Co single atoms and Co nanoparticles were tuned to possess higher catalytic activity and capture more oxygen species. As expected, the as-prepared electrocatalyst displays outstanding ORR performance with a half-wave potential of 0.9 V. The assembled Zn-air battery using this cathode catalyst shows a high-power density of 196 mW cm-2, superior to the commercial Pt/C catalysts. This work could inspire developing other biomimetic architectures for high-performance energy storage and conversion systems.
摘要:
Abstract: Ecologically fragile areas in China account for more than half of its land area. Performing early warning assessments and trend analyses of resource and environment carrying capacity in ecologically fragile areas can lay a scientific foundation for ecological conservation in the areas. Based on the connotation of resource and environment carrying capacity, an early warning index system of resource and environment carrying capacity in Altay prefecture was constructed from the three aspects natural resource carrying capacity, eco-environment carrying capacity, and economic and social support capacity. The grey relational projection method model was used to analyze the current alarm situation of the resource and environment carrying capacity in Altay prefecture from 2011 to 2020, and then the back propagation (BP) neural network and a mathematical statistics software were used to predict the evolution of the alarm situation of the resource and environment carrying capacity in Altay prefecture from 2021 to 2025. The results demonstrated that (1) the natural resource carrying capacity subsystem was the main system of the development of the resource and environment carrying capacity in Altay prefecture, and its impact on the resource and environment carrying capacity in Altay prefecture was greater than the eco-environment carrying capacity and economic and social support capacity; (2) the resource and environmental carrying capacity of Altay prefecture showed a slight upward trend from 2011 to 2020, although the range was constrained and the level of warning remained “moderate warning”. A spatial pattern of “weak in the middle, strong in the two poles” was exhibited by the warning scenario about the carrying capacity of each county and city. Except for the warning of Habahe County and Qinghe County, where the warning was slightly worse than that in 2020, the warning of resource and environment carrying capacity in Altay prefecture and other counties and cities would show a trend of fluctuation and decline from 2021 to 2025. However, the degree of alarm did not change substantially and remained at the level of “moderate warning”; (3) the main factors restricting the mitigation of the warning of resource and environment carrying capacity in Altay prefecture included a low soil fertility index, a small total reservoir capacity, low per capita mineral resource reserves, a low water resource development and utilization rate, a low comprehensive utilization rate of industrial solid waste, and a low land output rate. Keywords: resource and environment carrying capacity; ecologically fragile areas; grey relational projection method; BP neural network
摘要:
In this study, three coupled modes of coupling effect of sulfate attack and carbonation of concrete were carried out to investigate the change of mass, mechanical properties and apparent morphology. The phase composition, microstructure and morphological char-acteristics of erosion products were also studied by using environment scanning electron microscope (ESEM-EDS), Fourier infrared spectrometer (FTIR), and X-ray diffraction (XRD). The results indicated that the coupled mode played an obvious effect on the performance and microstructures of specimen due to effects of coupled mode on the deterioration mechanism and erosion products. The surface feature of specimen became worse with carbonation time, and plenty of surface efflorescence and desquamation of products were observed under the coupled mode of carbonation followed by sulfate attack. The relative compressive strength and dynamic elastic modulus of concrete specimen first increased and then decreased with carbonation time, and there existed relationship of a cubic function of single variable between them. The relative mass of concrete specimen increased with the increase of the erosion age of sulfate attack. The difference of the carbonation time per period test played a significant effect on the relative compressive strength and dynamic elastic modulus of concrete specimen, which was due to the dominant effect of carbonation.& COPY; 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
作者机构:
[Chen, Fei; Dong, Jie; Zeng, Wenbin; Huang, Shuai; Cheng, Xiang] Cent South Univ, Xiangya Sch Pharmaceut Sci, Changsha, Peoples R China.;[Qian, Jie] Cent South Univ Forestry & Technol, Natl Engn Res Ctr Rice & Byproduct Deep Proc, Sch Food Sci & Engn, Changsha 410004, Peoples R China.;[Yu, Kunqian; Jiang, Hualiang] Chinese Acad Sci, Shanghai Inst Mat Med, Drug Discovery & Design Ctr, State Key Lab Drug Res, Shanghai 201203, Peoples R China.
摘要:
Monitoring the physiological changes of organelles is essential for understanding the local biological information of cells, and for improving the diagnosis and therapy of diseases. Currently, fluorescent probes are considered as the most powerful tools for imaging and have been widely applied in biomedical fields. However, the expected targeting effects of these probes are often inconsistent with the real experiments. The design of fluorescent probes mainly depends on the empirical knowledge of researchers, which was inhibited by limited chemical space and low efficiency. Herein, we proposed a novel multi-level framework for the prediction of organelle-targeted fluorescent probes by employing advanced artificial intelligence algorithms. In this way, not only the targeting mechanism could be interpreted beyond intuitions but also a quick evaluation method could be established for the rational design. Furthermore, the targeting and imaging powers of the optimized and synthesized probes based on this methodology were verified by quantitative calculation and experiments.
摘要:
An efficient way to alleviate the pollution imposed by petroleum-based supplies like synthetic fibres and plastics is to prepare biocomposites from recyclable forestry waste with a continuous supply. Despite this, it remains a significant challenge in the field of wood-based panel manufacturing to produce high-performance yet environmentally friendly wood-based materials without the addition of chemical adhesives. Lignin can be used as a "natural adhesive" due to its superior bonding properties, but the dispersion of hemicellulose affects cross-linking at the interfacial interface negatively. This study used lignin/cellulose as a matrix and pretreated it with hydrogen peroxide, sodium hydroxide, sodium silicate solution and in situ bonding of wood fibres to create a high-performance biocomposite material for potential mass production. The findings revealed the tensile (106.63 MPa) and bending strengths (148.78 MPa) of the optimised samples were 125.37% and 91.40% higher than the performance before optimisation. Moreover, the biocomposite demonstrated remarkable hydrophobicity, as evidenced by a water contact angle of 99.96 & DEG;, and exhibited high thermal stability, without any disintegration observed even when subjected to combustion at 1300 & DEG;C. These exceptional properties and advantages render it a highly desirable material for eco-friendly homes and construction applications.