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1
Content available remote Investigation on resonant laser ablation spectrum of Fe in 281.5-285.5 nm wavelength region
100%
Ma J. , Ji X. , Cui Z.
Optica Applicata
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2008
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tom Vol. 38, nr 2
405-411
EN
Laser ablation of solid Ti samples has been studied using a tunable pulsed dye laser. Six resonant laser ablation (RLA) spectral lines of Fe in the Ti sample are firstly measured in the 281.5-285.5 nm wavelength region. The initial state of the RLA spectral lines is a5F, the resonant states are z5H0, x5P0 and y5G0, respectively. The influence of laser power density on the intensities of RLA spectrum is discussed. The relationship between the laser wavelength and the photo-ionization cross sections of the resonant state 5G0 is analyzed.
2
Content available A machine learning-based mobile robot visual homing approach
100%
Zhu Q. , Ji X. , Wang J. , Cai C.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2018
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tom Vol. 66, nr 5
621--634
EN
Visual homing enables mobile robots to move towards a previously visited location solely based on panoramic vision sensors. In this paper, a SIFT-based visual homing approach incorporating machine learning is presented. The proposed approach can reduce the impact of inaccurate landmarks on the performance, and generate more precise home direction with simple model. The effectiveness of the proposed approach is verified on both panoramic image databases and actual mobile robot, experimental results reveal that compared to some traditional visual homing methods, the proposed approach exhibits better homing performance and adaptability in both static and dynamic environments.
3
Content available remote Higher-order space charge field effects on the self-deflection of bright screening spatial solitons in two-photon photorefractive crystals
100%
Jiang Q. , Su Y. , Ji X.
Optica Applicata
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2010
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tom Vol. 40, nr 2
481--490
EN
We investigate the effects of higher-order space charge field on the self-deflection of bright screening spatial solitons due to two-photon photorefractive effects by a numerical method under steady-state conditions. The expression for an induced space charge electric field including higher-order space charge field terms is obtained. Numerical results indicate that bright screening solitons undergo self-deflection process during propagation, and the solitons always bend in the opposite direction of the c axis of the crystal. The self-deflection of bright screening solitons can experience considerable increase especially in the regime of high bias field strengths. Relevant examples are provided.
4
Identyfication of differentially expressed genes preferably related to drought response in pigeon pea (Cajanus cajan) inoculated by arbuscular mycorrhizae fungi (AMF)
100%
Qiao G. , Wen X. , Yu L. , Ji X.
Acta Physiologiae Plantarum
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2012
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tom 34
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nr 5
EN
Pigeon pea is an ideal crop for sustainable agriculture systems in Karst areas of southwest China, which frequently suffers from the formidable water deficit. Physiologically, arbuscular mycorrhizae (AM)-colonized pigeon pea (Cajanus cajan) demonstrated a further enhanced tolerance to drought stress. To elucidate the molecular mechanism underlying the elevated tolerance, suppression subtractive hybridization (SSH) were employed to dig up the differentially expressed genes using mixed cDNAs prepared from drought-stressed and unstressed pigeon pea seedlings inoculated by AM fungi (AMF) in the present work. Both forward and reverse SSH cDNA library were constructed and a total of 768 clones were obtained. Dot-blotting expression analysis identified that 142 clones were upregulated, and 49 were downregulated during water stress. After sequencing, 182 unique expressed sequence tags (ESTs) were obtained via blast analysis, among which 142 (78%) exhibited high homology to previously identified or putative proteins, however, 40 (22%) showed no homology in the database. The upregulated (102) and downregulated (40) ESTs with significant protein homology might be sorted into 16 and 12 functional categories respectively, which involved in a broad spectrum of biological pathways. Furthermore, semi-quantitative reverse transcription (RT)-PCR was carried out for the 35 differentially expressed genes whose putative functions implicated in abiotic stress tolerances in other species, and it was verified these differentially expressed genes highly involved in drought stress tolerance of AM-colonized pigeon pea.
5
Content available remote Displacement Self-sensing of Bearingless Switched Reluctance Motors Based on LS-SVM
100%
Zhu Z. , Sun Y. , Huang Y. , Ji X.
Przegląd Elektrotechniczny
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2012
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tom R. 88, nr 12a
310-313
EN
To achieve the rotor radial displacement self-sensing for a bearingless switched reluctance motor (BSRM), a new displacement estimation method using least squares support vector machine (LS-SVM) was proposed. Firstly, the working principle and mathematic of a 3-phase 12/8 pole BSRM was introduced in brief. Then taking advantage of LS-SVM with better solution for small-sample learning problem and strong generalization ability, two LS-SVMs were trained off-line to obtain two efficient nonlinear mapping structures to express the dynamic behavior of BSRM. The LSSVM training data set is comprised of representative experimental data with current {i | i = (isa1, isa2, ima)} and rotor position θ as inputs and the corresponding displacements {D | D=(α , β )}as outputs. As well as giving a detailed explanation of the new method, simulation and experimental results were presented. It shows that the proposed LS-SVM-based displacement self-sensing method has high precision and operation efficiency.
PL
W artykule przedstawiono uczący się estymator przesunięcia dla bezłożyskowego silnika o przełączanej reluktancji (BSRM), wykorzystujący metodę LS-SVM (ang. Least Square Support Vector Machines). Opisano zasadę działania i model matematyczny silnika BSRM 3- fazowego 12/8 biegunowego. W celu uzyskania efektywnej struktury mapowania nieliniowego do określenia stanów dynamicznych, zastosowano dwa algorytmy, które zostały nauczone offline. Estymator poddano weryfikacji symulacyjnej i eksperymentalnej.
6
Content available remote Rotor Displacement Estimation for MB Sensorless Control
100%
Zhu Z. , Sun Y. , Huang Y. , Ji X.
Przegląd Elektrotechniczny
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2012
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tom R. 88, nr 1b
141-145
EN
This paper presents an on-line recursive least squares support vector machine(O-RLS-SVM)-based displacement estimator for magnetic bearings (MBs). The basic premise of the method is that an O-RLS-SVM forms an efficient mapping structure for a nonlinear MB. Through the measurement of phase flux linkages and currents, the O-RLS-SVM is able to estimate the rotor displacement; thereby it facilitates the elimination of the rotor displacement sensor. Simulation results show that the estimator has high estimation precision and favourable operation efficiency.
PL
W artykule przedstawiono system estymacji położenia wirniku w maszynach z poduszką magnetyczną. System nie wymaga czujników – miarą położenia wirnika są przesunięcia fazowe prądu i strumienia magnetycznego.
7
Content available Mobile robot visual homing by vector pre-assigned mechanism
88%
Ji X. , Zhu Q. , Wang J. , Cai C. , Ma J.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2019
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tom Vol. 67, nr 2
213--227
EN
In this paper, we present an optimization mechanism for two popular landmark-based mobile robot visual homing algorithms (ALV and HiSS), called vector pre-assigned mechanism (VPM). VPM contains two branches, both of which can promote the homing performance effectively. In addition, to make the landmark distribution satisfy the equal distance assumption, a landmark optimization strategy is proposed based on imaging principle of the panoramic vision. Experiments on both panoramic image database and a real mobile robot have confirmed the effectiveness of the proposed methods.
8
Relationships between soil nutrients and plant diversity in riparian woodlands along the middle and lower reaches of the Yellow river, China
75%
Zhao Q. , Xu S. , Tang Q. , Lu X. , Wang S. , Ji X. , Ding S.
Polish Journal of Environmental Studies
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2020
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tom 29
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nr 3
9
Decreased expression of the human carbonyl reductase 2 gene HCR2 in hepatocellular carcinoma
63%
Liu S. , Ma L. , Huang W. , Shai Y. , Ji X. , Ding L. , Liu Y. , Yu L. , Zhao S.
Cellular and Molecular Biology Letters
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2006
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tom 11
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nr 2
EN
Altered gene expression was associated with the induction and maintenance of hepatocellular carcinoma (HCC). To determine the significance of HCR2 in HCC, here we compare the expression levels of HCR2 in carcinoma and in paired non-carcinoma tissues using semiquantitative reverse-transcription polymerase chain reaction (RT-PCR), Western blot analysis, and immunohistochemical staining. The expression ratio (ER) of HCR2 between the tumor and paired tumor-free tissues was calculated for each case and the data was clinicopathologically analyzed. The expression of HCR2 mRNA was found to be significantly decreased in HCC tissues compared with paired normal tissues (P < 0.001). HCR2 was downregulated in 58% (n = 22) of 38 HCC patients. The ER of HCR2 was higher in Edmondson’s grade I/II carcinomas than that in Edmondson’s grade III/IV carcinomas (P < 0.05). Western blot analysis showed HCR2 to be notably depressed in carcinoma tissues in 3 out of 4 HCC patients. Immunohistochemical staining indicated most HCR2 protein accumulated in non-carcinoma cells. These results suggested that altered HCR2 expression might play roles in the carcinogenesis and progression of HCC, and it could be a clinical marker for prognosis, and a molecular target for screening potential anti-HCC drugs.
10
Content available A machine learning-based mobile robot visual homing approach
63%
Zhu Q. , Ji X. , Cai C. , Wang J.
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