Wyniki wyszukiwania - Biblioteka Nauki

1

Climbing Robot Modelling Based on Grab Claws

100%

Xu F. , Jiang G.

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tom R. 89, nr 3b

182--187

EN

Though the wall-climbing robots have be used extensively, however, no effective adhesion system has been designed for robots deployed in high-altitude, rough concrete buildings that are subjected to large wind loads and vibrations. Therefore, an initial design of a wall-climbing robot based on grab claw is presented and a climbing model is proposed in the paper. The mathematical model is established to reflect the relations between sharp hook and the micro-protuberance on the rough wall surface The stress on the hook-like claws is analyzed under three different conditions, so the steady grasping condition of the hook-like claws is obtained. Simulation results are carried out which demonstrates the stability of the grasping. Finally, the system outline and field implement scheme are presented.

PL

W artykule przedstawiono projekt wspinającego się robota, opartego na chwytaku w postaci pazura. Zaproponowano także matematyczny model wspinania, pozwalający określić wpływ mikro-fałd na powierzchni pionowej na możliwość chwytania hakiem. Przeanalizowano możliwości obciążenia haka w trzech różnych warunkach pracy. Przeprowadzono badania symulacyjne i eksperymentalne w celu weryfikacji modelu.

2

Human sperm acrosomal status, acrosomal responsiveness, and acrosin are predictive of the outcomes of in vitro fertilization: a prospective cohort study

80%

Xu F. , Zhu H. , Zhu W. , Fan L.

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nr 4

3

Spiking Neural P Systems with Rules on Synapses Working in Sum Spikes Consumption Strategy

80%

Su Y. , Wu T. , Xu F. , Păun A.

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tom Vol. 156, nr 2

187--208

EN

Spiking neural P systems with rules on synapses (RSSN P systems, for short) are a class of distributed and parallel computation models inspired by the way in which neurons process and communicate information with each other by means of spikes, where neurons only contain spikes and the evolution rules are on synapses. RSSN P systems have been proved to be Turing universal, using the strategy that restricts all the applied rules to consume the same number of spikes from the given neuron, termed as equal spikes consumption strategy. In this work, in order to avoid imposing the equal spikes consumption restriction on the application of rules, a new strategy for rule application, termed as sum spikes consumption strategy, is considered in RSSN P systems, where a maximal set of enabled rules from synapses starting from the same neuron is nondeterministically chosen to be applied, in the sense that no further synapse can use any of its rules, and the sum of these numbers of spikes that all the applied rules consume is removed from the neuron. In this way, the proposed strategy avoids checking whether all the applied rules consume the same number of spikes from the given neuron. The computation power of RSSN P systems working in the proposed strategy is investigated, and it is proved that such systems characterize the semilinear sets of natural numbers, i.e., such systems are not universal. Furthermore, RSSN P systems with weighted synapses working in the proposed strategy are proved to be Turing universal. These results show that the weight on synapses is a powerful ingredient of RSSN P systems in terms of the computation power, which makes RSSN P systems working in sum spikes consumption strategy become universal from non-universality.

4

Nondestructive Evaluation of Rubber Composites Using Terahertz Time Domain Spectroscopy

71%

Xu F. , Duan Mu Q. D. , Li L. J. , Yang D. , Xia B.

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tom Vol. 26, no. 1 (127)

67--72

EN

In recent years, with the progress of science, more and more detection methods are being used in various fields. However, the nondestructive testing of nonmetallic materials still needs further study. In this paper, an analysis of the time domain characteristics of rubber materials using terahertz detection technology was carried out, obtaining different defect rubber material spectral characteristics as well as imaging results and data. The results show that the THz spectrum imaging technique can detect the thickness of rubber material in the 0.1 ~ 4.0 terahertz band, and the image is clear and the resolution high. Meanwhile the time domain waveform obtained is sensitive to the debonding defects of the sample rubber, is suitable for judging the overall performance of the rubber inner defect detection, and can provide the scientific basis for rubber material performance.

PL

W artykule przedstawiono analizę charakterystyk materiałów gumowych z wykorzystaniem technologii wykrywania terahercowego, uzyskując różne charakterystyki spektralne defektów gumy, a także wyniki i dane obrazowe. Wyniki pokazały, że technika obrazowania widma THz może wykrywać grubość materiału gumowego w paśmie 0,1 ~ 4,0 terahercowym, a obraz jest wyraźny i ma wysoka rozdzielczość. W międzyczasie otrzymany przebieg domeny czasu jest wrażliwy na defekty badanej gumy, jest odpowiedni do oceny ogólnej wydajności wykrywania wewnętrznego defektu gumy i może zapewnić podstawy dla oceny właściwości materiału gumowego.

5

The Wnt7b/β-catenin signaling pathway is involved in the protective action of calcitonin gene-related peptide on hyperoxia-induced lung injury in premature rats

71%

Wang S. , Dang H. , Xu F. , Deng J. , Zheng X.

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tom 23

EN

Background: Calcitonin gene-related peptide (CGRP) can protect against hyperoxia-induced lung injury, making the upregulation of CGRP a potential therapeutic approach for this type of injury. However, the effects of CGRP on the Wnt7b/β-catenin signaling pathway are unclear. In this study, we investigated the roles of CGRP and the Wnt7b/β-catenin signaling pathway in hyperoxia-induced lung injury. Methods: Premature Sprague Dawley (SD) rats were exposed to 21, 40, 60 and 95% oxygen for 3, 7 and 14 days. The animals’ body weights, survival rates and endogenous CGRP levels were measured. Lung samples were harvested for histological analyses and measurements of malondialdehyde (MDA) concentration and total antioxidant capacity (TAOC). We also assessed the MDA concentration and TAOC in the lung tissues after administration of 200 nmol/kg CGRP8–37 (a CGRP antagonist). Finally, alveolar epithelial type II (AEC II) cells were isolated from premature rats, exposed to 21 or 95% oxygen for 3, 7 and 14 days, and treated with 10− 8 mol/l exogenous CGRP. The protein expressions of Wnt7b and β-catenin were assessed using western blotting, and TCF and c-myc mRNA expressions were assessed using qPCR. Results: Rats exposed to 60 and 95% oxygen had significantly lower body weights and survival rates than the 21 and 40% groups, and the decrease was time dependent. Endogenous CGRP was elevated in the lung tissues of premature rats exposed to 95% oxygen. CGRP8–37 induced apparent inflammation in the lung tissue and alveolar structural remodeling. In addition, the expression levels of Wnt7b and β-catenin were markedly increased after exposure for 3 days. They peaked at 7 days, then declined at 14 days. The levels of TCF/c-myc in AEC II cells increased significantly after CGRP treatment when compared with cells that had only undergone hyperoxia. Conclusions: CGRP protected against hyperoxia-induced lung injury in premature rats. This process involves the Wnt7b/β-catenin signaling pathway.

6

The Response of Wetland Plant Communities to Disturbance : Alleviation through Symmetric Disturbance and Facilitation

61%

Xu F. , Li M. , Zhou D. , Liu X. , Wang R. , Guo W.

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tom Vol. 64, nr 3

327--338

EN

The study pays attention to disturbances in early successional communities of wetland vegetation. We conducted artificial disturbances in a community of Suaeda salsa and Phragmites australis in the Yellow River Delta (China). Eight types of disturbances combining mowing treatments with species treatments were applied. Removal of the standing litters of P. australis or not was defined as mowing treatments, and removal of two species solo or both was defined as species treatments. We sampled 80 quadrats from the treatments plots at different intervals after the disturbance to investigate plant height, abundance, aboveground biomass, the distance between plants to reflect the effect of disturbance on composition, structure, productivity, and function of the plant communities. The strategies of seedling emergence and height growth differed as the canopy changed. Biomass contribution of different species, combined with disturbance intensity, was the main factors that affected the productivity. Homogeneity of disturbance was better for maintaining the functions of plant community in compared with the competitiveness (C), stress-tolerance (S) and ruderality (C-S-R) signatures with the control. Facilitations were reflected by the stagger arrangements in relative growth rates of the two species and in plant-plant interactions calculated by a modified function of competition. Adapting to symmetric disturbance and developing facilitative interactions are important requirements for early succession terrestrial vegetation to establish and stabilize in the seriously saline environments of wetlands.

7

Isolation, characterization and functional analysis of a novel 3-hydroxy-3-methylglutaryl-coenzyme A synthase gene (GbHMGS2) from Ginkgo biloba

61%

Meng X. , Xu F. , Song Q. , Ye J. , Liao Y. , Zhang W.

Acta Physiologiae Plantarum

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2018

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tom 40

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nr 04

8

Comparative expression analysis of dehydrins between two barley varieties, wild barley and Tibetan hulless barley associated with different stress resistance

51%

Du J.-B. , Yuan S. , Chen Y.-E. , Sun X. , Zhang Z.-W. , Xu F. , Yuan M. , Shang J. , Lin H.-H.

Acta Physiologiae Plantarum

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2011

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tom 33

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nr 2

EN

Drought, salinity and cold are the major environmental factors impacting on survival and productivity of Tibetan hulless barley in Tibetan Plateau of China. Tibetan hulless barley cultivar, Tibetan Heiqingke No. 1, has developed a strong tolerance and adaptation to stresses in relation to the wild barley. The differences of dehydrin gene transcription and translation between Tibetan Heiqingke No. 1 and the wild barley under drought, salinity and low temperature stresses were investigated in the present study to figure out the putative mechanism of stress tolerance of Tibetan Heiqingke No. 1. The leaf relative water contents (RWCs) decreased more slowly in Tibetan hulless barley than the wild barley under osmotic and low temperature conditions. Electrolyte leakage, malondialdehyde and H₂O₂ contents increased faster in wild barley than those of Tibetan hulless barley, which indicated that cells of wild barley received more damages than Tibetan hulless barley. Furthermore, the expression of several dehydrin genes, belonging to four different classifications respectively, was also investigated. Polyclonal antibodies against dehydrins were obtained from rabbit after prokaryotic expression and purification of TDHN4, a dehydrin protein from Tibetan hulless barley. With these antibodies and dehydrin gene fragments, western blotting analysis and RT-PCR showed that Tibetan Heiqingke No. 1 accumulated higher abundance of dehydrins than stresssensitive wild barley under all stress conditions.