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1

Dynamic behavior of an imbalanced and warped Jeffcott rotor with asymmetric stiffness

100%

Lin F. , Meng G. , Fang T.

International Journal of Applied Mechanics and Engineering

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2007

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tom Vol. 12, no 4

1039-1048

EN

The dynamic behaviour of an imbalanced and warped Jeffcott rotor with asymmetric stiffness was studied theoretically and experimentally. The rotor response was analyzed and discussed under different rotating speeds and angle ranges between the directions of the bend and imbalance. It was noted that the angle between the directions of the warp and the imbalance plays a key role in controlling the rotor response and effect of the angle varied by the magnitude of bend. If the angle is larger than [...] and smaller than [...] in radian, the rotor response will decrease due to imbalance. Particularly for sufficiently large angles, the response amplitude will decrease with increasing rotating speed. This effect will take place before passing the first critical rotating speed, if the magnitude of the warp is smaller than the eccentricity; and will take place after passing the first critical rotating speed, if the magnitude of the warp is larger than the eccentricity. A double frequency response also happened in an imbalanced rotor with initial bow and asymmetric stiffness; the supposed stationary response will lose its stability as the rotating speed lies in the range between the first two critical speeds. Good agreement was achieved between the numerical solutions and the experimental results to verify the proposed model capability, which may contribute to the diagnosis of asymmetric stiffness and the residual warp of the rotor.

2

Involvement of haem oxygenase-1 in hydrogen peroxide-induced lateral root formation in tomato

75%

Cao Z. , Fang T. , Chen M. , Li J. , Shen W. , Huang L.

Acta Physiologiae Plantarum

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2014

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tom 36

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nr 04

EN

The objective of this study was to test whether haem oxygenase-1 (HO-1) is involved in hydrogen peroxide (H₂O₂)-induced lateral root (LR) formation. The results showed that 0.1 mM H₂O₂ mimicked the effects of the HO-1 inducer, haemin, on the up-regulation of tomato HO-1 (SlHO1) expression, increased carbon monoxide (CO) synthesis and LR formation. However, 1.0 mM H₂O₂ resulted in inhibitory responses. The above inducible or inhibitory responses elicited by 0.1 and 1.0 mM H₂O₂ were noticeably blocked or rescued by the HO-1 inhibitor zinc protoporphyrin IX (ZnPP) or haemin, and then separately reversed by CO or ZnPP. Further trials showed that haemin-induced responses were not altered by the H₂O₂ trap, dimethylthiourea (DMTU). When applied alone, DMTU not only decreased H₂O₂ contents but also inhibited SlHO1 expression and LR development. These responses were recovered by the application of haemin or CO. Molecular evidence revealed that H₂O₂-modulated expression of the target genes responsible for LR formation was blocked by ZnPP, but rescued by CO. Salinity-induced up-regulation of HO-1 expression and thereafter LR formation were also dependent on the H₂O₂ generation. Overall, these results demonstrated a possible role of HO-1 in the H₂O₂-induced tomato LR formation.

3

Comparison of physiological and methylational changes in resynthesized Brassica napus and diploid progenitors under drought stress

75%

Jiang J. , Yuan Y. , Zhu S. , Fang T. , Ran L. , Wu J. , Wang Y.

Acta Physiologiae Plantarum

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2019

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tom 41

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nr 04

EN

Brassica napus is a polyploid of certain research and economical value. Resynthesizing B. napus with diploid B. rapa and B. oleracea is essential for Brassica research because of the limited genetic background of B. napus. Considering that polyploids possess better agronomic traits and resistance compared with the corresponding diploids, we investigated drought tolerance after polyploidization of B. napus and revealed the epigenetic differences between polyploids and diploids. After drought stress, B. rapa and first-generation of synthesized hybrids (F1) were more wilted than B. oleracea and F2–F4 generations. However, the relative water content and water retention in F1 were better than others after drought stress. The increased number of partially opened and closed stomata in F1 was not as significant as that in F2 and F3, but stomata density in F1 was lower than F2, and the stomatal size in F1 was significantly reduced than F3. Physiological parameters varied among different generations of B. napus and diploid parents, and most of these parameters in hybrids were higher than B. rapa and lower than B. oleracea. However, the peroxidase activity in F3 and F4 was significantly higher than both parents, and the malondialdehyde content in F3 and F4 was lower than both parents, indicating that F3 and F4 might be more adaptive to oxidative stresses than other generations. DNA methylation level was decreased in F2 and F3 compared with F1, and then increased in F4. Methylation-sensitive amplified polymorphism analysis revealed that DNA methylation and demethylation broadly happened after drought stress. The methylation and demethylation level was F1 > F4 > B. oleracea > F2 > F3 > B. rapa and B. rapa > F4 > F3 > F2 > B. oleracea > F1, respectively. The epigenetic changes under drought stress might be related to the different stress tolerances during B. napus polyploidization.

4

Generation of chirped microwave signal with any central frequency based on a nonuniformly spaced finite impulse response filter

75%

Chen D. , Wang R. , Pu T. , Xiang P. , Fang T. , Zheng J. , Xiong J.

Optica Applicata

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2016

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tom Vol. 46, nr 3

399--408

EN

A novel optical approach to generating a chirped microwave signal by using a nonuniformly spaced finite impulse response filter is proposed and demonstrated. In this scheme, a narrowband Gaussian pulse is used as the original chirped-free signal, which is easy to be acquired. To eliminate the need of a wideband chirped-free signal, a mixer and a radio frequency signal are used to up-convert the spectrum of the original Gaussian signal. Therefore, the required frequency response can be calculated and reconstructed by a finite impulse response filter with nonuniformly spaced taps. Besides, a dual drive Mach–Zehnder modulator is used to realize single sideband modulation of the chirpedfree signal. Thus, the transfer function induced by the fiber dispersion is eliminated and the chirped microwave signal with any central frequency can be generated. In this paper, a design example of a filter with a central frequency of 10GHz is provided, and generation of the target chirped microwave signal is also demonstrated by numerical simulations.

5

Dispersion-compensating en/decoder for a time-spreading/wavelength-hopping optical code-division multiplexing (OCDM) system

63%

Zheng J. , Wang R. , Pu T. , Lu L. , Fang T. , Su Y. , Li L. , Yang Q. , Chen X.

Optica Applicata

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2013

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tom Vol. 43, nr 3

485--495

EN

A novel dispersion-compensating fiber Bragg grating (FBG)-based en/decoder is proposed to compensate both the out-band and in-band dispersion in a time-spreading/wavelength-hopping (TS/WH) optical code-division multiplexing (OCDM) system. The experimental realization of such en/decoders only needs a uniform-pitch phase mask and a sub-micrometer precision moving stage. Such an en/decoder pair with the ability of compensating the dispersion of transmission in 20-km single mode fiber (SMF) is simulated and experimentally fabricated. Both the simulation and experimental results show that the decoded pulse can be recovered without any distortion owing to the elimination of dispersion.

6

The impacts of crustacean zooplankton on a natural ciliate community: a short-term incubation experiment

63%

Li J. , Yang K. , Chen F. , Lu W. , Fang T. , Zhao X. , Li H. , Cui K.

Acta Protozoologica

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2017

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tom 56

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nr 4

7

Effects of spermine supplementation on blood biochemical parameters, amino acid profile and ileum expression of amino acid transporters in piglets

63%

Fang T. , Jia G. , Zhao H. , Chen X. , Wu C. , Xue B. , Cai J. , Tian G. , Wang J. , Liu G.

Journal of Animal and Feed Sciences

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2019

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tom 28

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nr 4