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1

Path following control of the underactuated USV based on the improved line-of-sight guidance algorithm

100%
Liu T., Dong Z., Du H., Song L., Mao Y.
Polish Maritime Research
|
2017
|
tom 24
|
nr 1
The path following control problem of the underactuated unmanned surface vessel (USV) is studied in this paper. An improved line-of-sight (LOS) guidance algorithm is proposed which can adjust adaptively based on the path following error. The global asymptotically stable path following controller is designed based on the nonlinear backstepping method and the Lyapunov stability theory. Firstly, the USV path following error model is established in the Serret-Frenet (SF) coordinate frame. The path following error in the inertial coordinate frame is transformed into the SF coordinate frame, which is used to define the path following control problem. Secondly, inspired by the traditional LOS guidance algorithm, the longitudinal path following error in the SF coordinate frame is introduced into the improved LOS guidance algorithm. This allows the algorithm to adjust adaptively to the desired path. Thirdly, in order to solve the underactuated problem of the USV path following control system, the tangential velocity of the desired path is designed as a virtual input. The underactuated problem is converted to a virtual fully actuated problem by designing the virtual control law for the tangential velocity. Finally, by combining backstepping design principles and the Lyapunov stability theory, the longitudinal thrust control law and the yaw torque control law are designed for the underactuated USV. Meanwhile, the global asymptotic stability of the path following error is proved. Simulation experiments demonstrate the effectiveness and reliability of the improved LOS guidance algorithm and the path following controller
2

Error mitigation algorithm based on bidirectional fitting method for collision avoidance of unmanned surface vehicle

100%
Song L., Chen Z., Mao Y., Dong Z., Xiang Z.
Polish Maritime Research
|
2018
|
tom 25
|
nr 4
Radars and sensors are essential devices for an Unmanned Surface Vehicle (USV) to detect obstacles. Their precision has improved significantly in recent years with relatively accurate capability to locate obstacles. However, small detection errors in the estimation and prediction of trajectories of obstacles may cause serious problems in accuracy, thereby damaging the judgment of USV and affecting the effectiveness of collision avoidance. In this study, the effect of radar errors on the prediction accuracy of obstacle position is studied on the basis of the autoregressive prediction model. The cause of radar error is also analyzed. Subsequently, a bidirectional adaptive filtering algorithm based on polynomial fitting and particle swarm optimization is proposed to eliminate the observed errors in vertical and abscissa coordinates. Then, simulations of obstacle tracking and prediction are carried out, and the results show the validity of the algorithm. Finally, the method is used to simulate the collision avoidance of USV, and the results show the validity and reliability of the algorithm
3

Changes of extracellular polymeric substance (EPS) during microcystis aeruginosa blooms at different levels of nutrients in a eutrophic microcosmic simulation device

86%
Wang Q., Pang W., Mao Y., Ge S., Yu H., Dai C., Zhao M.
Polish Journal of Environmental Studies
|
2020
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tom 29
|
nr 1
4

Effects of freezing and freeze-thaw cycles on soil microbial biomass and nutrient dynamics under different snow gradients in an Alpine meadow (Tibetan Plateau)

86%
Liu L., Wu Y., Wu N., Xu J., Mao Y., Luo P., Zhang L.
Polish Journal of Ecology
|
2010
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tom 58
|
nr 4
In alpine zones, cold season processes, particularly those associated with snow accumulation and ablation, have a central role in ecosystem functioning. However, we know very little about soil carbon and nitrogen processes under the snowpack in these ecosystems, including the Tibetan Plateau. We conducted an experiment comparing three snow regimes (11 m × 1 m plots) of different snow depths and durations at an altitude of 4,100 m in the Minshan Range on the eastern Tibetan Plateau. The three snow regimes included a shallow and short duration snowpack (SS; depth <10 cm), a moderate snow depth and medium duration snowpack (MS; depth <20 cm), as well as a deep and long duration snowpack (DS; depth > 30 cm). This study explores the effects of different snow conditions on soil temperature, and further describes the sequence and timing of dissolved nutrients and microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) in soils under different snow regimes during the autumn-winter transition (i.e. November 7, 2008 – March 7, 2009). Three successive phases of temperature change were distinguished: I – initial decline – soil temperatures dropped steadily from 4°C to about 0°C at the same rate for all three snow regimes; II – moderate freezing – soil temperatures fluctuated between 0°C and –7°C under all three snow regimes; III – multiple freeze-thaw cycles took place in the SS and MS regimes, but permanent freezing occurred in the DS regime. Under moderate freezing, we found that soil temperature fluctuation was an essential factor for the transformation of soil C and N. Our results indicate that larger temperature fluctuations correlate with a greater increase in dissolved organic nitrogen (DON) content. Dissolved organic carbon (DOC) content increased markedly only under the most drastic temperature fluctuations. In contrast, MBC content increased significantly only when soil temperatures were relatively steady. Under the permanent freezing, only a large number of freeze-thaw cycles caused a significant decline of NO₃⁻–N and DOC concentrations. DON content declined markedly under permanent freezing and multiple freeze-thaw cycles. However, MBC content declined significantly only under permanent freezing. Ultimately, multiple freeze-thaw cycles resulted in the export of dissolved nutrients (organic and inorganic nitrogen) from the alpine ecosystem which had previously accumulated in the moderate freezing phase of the soil.
5
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Vertical transmission of PCV2b to fetuses in sows intramuscularly infected with PCV2b

72%
Wang N. D., Li J. J., Wang A. B., Zhu Z., Chang Y., Mao Y., Zan Y., Wang Z. F., Deng Z. B.
Polish Journal of Veterinary Sciences
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2016
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tom 19
|
nr 3
In order to investigate whether PCV2b can be transmitted across the placenta in sows thereby causing vertical infection of fetuses, six sows in 75 day of pregnancy were either intramuscularly inoculated with a PCV2b culture supernatant (n = 4) or mock infected with cell culture supernatant (n = 2). At parturition, 3 newborn piglets from each litter were randomly selected and euthanatized prior to suckling. Samples of the mesenteric lymph nodes, spleens, kidneys, hearts and lungs were collected for PCR, histopathological and immunohistochemical assays. The results showed that the newborn piglets from PCV2b-infected sows had histopathological lesions in the tested tissues. Moreover, PCV2b antigen and DNA were detected as well. These findings therefore suggested that porcine circovirus type 2b can be transmitted across the placenta of sows, thereby leading to PCV2b vertical infection of the fetuses.
6

Molecular cloning and characterization of a novel human gene containing 4 ankyrin repeat domains

72%
Li J., Ji C., Zheng H., Fei X., Zheng M., Dai J., Gu S., Xie Y., Mao Y.
Cellular and Molecular Biology Letters
|
2005
|
tom 10
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nr 1
7

Isolation and expression pattern of RGS21 gene, a novel RGS member

72%
Li X., Chen L., Ji C., Liu B., Gu J., Xu J., Zou X., Gu S., Mao Y.
Acta Biochimica Polonica
|
2005
|
tom 52
|
nr 4
Regulators of G-protein signaling (RGS) proteins are known for the RGS domain that is composed of a conserved stretch of 120 amino acids, which binds directly to activated G-protein α subunits and acts as a GTPase-activating protein (GAP), leading to their deactivation and termination of downstream signals. In this study, a novel human RGS cDNA (RGS21), 1795 bp long and encoding a 152-amino acid polypeptide, was isolated by large-scale sequencing analysis of a human fetal brain cDNA library. Unlike other RGS family members, RGS21 gene has no additional domain/motif and may represent the smallest known member of RGS family. It may belong to the B/R4 subfamily, which suggests that it may serve exclusively as a negative regulator of αi/o family members and/or αq/11. PCR analysis showed that RGS21 mRNA was expressed ubiquitously in the 16 tissues examined, implying general physiological roles.
8

Overexpression of BimSs3, the novel isoform of Bim, can trigger cell apoptosis by inducing cytochrome c release from mitochondria

72%
Liu L., Chen J., Zhang J., Ji C., Zhang X., Gu S., Xie Y., Mao Y.
Acta Biochimica Polonica
|
2007
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tom 54
|
nr 3
Bim is defined as the pro-apoptotic BH3-only protein of the Bcl-2 family, which is a critical sensor and mediator in the mitochondrial-dependent apoptosis. In a previous work, we have cloned a novel transcript of Bim (GenBank accession number: AY305716) from the fetal brain cDNA, which is widely expressed in some carcinoma tissues and normal human tissues. According to the sequence analysis and the newly-defined nomenclature system of Bim isoforms (Adachi et al., 2005, Cell Death Differ 2: 192), we term it BimSs3 according to its characteristic structure. The subcellular location analysis indicated that the fused protein GFP-BimSs3 is distributed in the whole cell, mainly to the nucleus. Overexpression of BimSs3 in HEK293 cells causes apoptosis (28.16 ± 1.55%) compared to the negative control (5.44 ± 2.63%). It also causes cytochrome c release from the mitochondrial fraction to the cytosolic fraction during apoptosis. Western blotting assay indicates the molecular mass of GFP-BimSs3 is approximately 31.0 kDa (GFP: 27 kDa). Hence the open reading frame of BimSs3 may initiate at the second ATG and encodes a 36 amino-acid peptide with BH3 domain.
9

Seasonal dynamics of gastrointestinal nematode infections of goats and emergence of ivermectin resistance in Haemonchus contortus in Hubei Province, China

59%
Yuan W., Lu K., Li H., Liu J., He C., Feng J., Zhang X., Mao Y., Hong Y., Zhou Y., Lu J., Jin Y., Lin J.
Acta Parasitologica
|
2019
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tom 64
|
nr 3
10

cDNA cloning, gene organization and expression analysis of human peptidylarginine deiminase type VI

59%
Zhang J., Dai J., Zhao E., Lin Y., Zeng L., Chen J., Zheng H., Wang Y., Li X., Ying K., Xie Y., Mao Y.
Acta Biochimica Polonica
|
2004
|
tom 51
|
nr 4
Peptidylarginine deiminase (PAD) catalyzes the post-translational modification of protein through the conversion of arginine to citrulline in the presence of calcium ions. Human, similar to rodents, has four isoforms of PAD (type I, II, III and IV/V), each of which is distinct in substrate specificity and tissue specific expression. In our large-scale sequencing project, we identified a new human PAD cDNA from a human fetal brain cDNA library. The putative protein encoded by this cDNA is designated hPADVI. Expression analysis of hPADVI showed that it is mainly expressed in adult human ovary and peripheral blood leukocytes. We conclude that hPADVI may be orthologous to mouse ePAD, basing on sequence comparison, chromosome localiza­tion and exon-intron structure analysis. PAD-mediated deimination of epithelial cell keratin resulting in cytoskeletal remodeling suggests a possible role for hPADVI in cytoskeletal reorganization in the egg and in early embryo development. This study describes a new important member of the human PAD family.
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