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Off-grid direction-of-arrival estimation for wideband noncircular sources
Xiaoyu Zhang1,Haihong Tao,Ziye Fang,Jian Xie 한국전자통신연구원 2023 ETRI Journal Vol.45 No.3
Researchers have recently shown an increased interest in estimating the direction-of-arrival (DOA) of wideband noncircular sources, but existing studies have been restricted to subspace-based methods. An off-grid sparse recovery-based algorithm is proposed in this paper to improve the accuracy of existing algorithms in low signal-to-noise ratio situations. The covariance and pseudo covariance matrices can be jointly represented subject to block sparsity constraints by taking advantage of the joint sparsity between signal components and bias. Furthermore, the estimation problem is transformed into a single measurement vector problem utilizing the focused operation, resulting in a significant reduction in computational complexity. The proposed algorithm's error threshold and the Cramer–Rao bound for wideband noncircular DOA estimation are deduced in detail. The proposed algorithm's effectiveness and feasibility are demonstrated by simulation results.
A New ent-Kaurane type Diterpenoid Glycoside from Inula japonica Thunb
Jiang Jiang Qin,Jia Xian Zhu,Wei Dong Zhang1,2,Yan Zhu,Jian Jun Fu,Xiao Hua Liu,Hui Zi Jin 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.10
A new ent-kaurane type diterpenoid glycoside, 17-O-β-D-glucopyranosyl-16α-ent-kauran-19-oic acid (1), together with 17-hydroxy-16α-ent-kauran-19-oic acid (2), 16α,17-dihydroxyl-ent-kauran-19-oic acid (3), and 16α-hydroxy-17-acetoxy-ent- kauran-19-oic acid (4) were isolated from the aerial parts of Inula japonica Thunb. The structure of 1 was determined mainly by use of 1D and 2D NMR spectroscopic techniques including HSQC, 1H-1H COSY, HMBC, and NOESY. In addition, 4 exhibited significant inhibitory activity on NO production in LPS-stimulated RAW264.7 cells with IC50 value of 14.3 μg/mL.
Zhang, Jian,Li, Shucai,Li, Liping,Zhang, Qianqing,Xu, Zhenhao,Wu, Jing,He, Peng Techno-Press 2017 Geomechanics & engineering Vol.12 No.1
In order to evaluate the grouting effects of water-rich fault in tunnels systematically, a feasible and scientific method is introduced based on the extension theory. First, eight main influencing factors are chosen as evaluation indexes by analyzing the changes of permeability, mechanical properties and deformation of surrounding rocks. The model of evaluating grouting effects based on the extension theory is established following this. According to four quality grades of grouting effects, normalization of evaluation indexes is carried out, aiming to meet the requirement of extension theory on data format. The index weight is allocated by adopting the entropy method. Finally, the model is applied to the grouting effects evaluation in water-rich fault F4-4 of Qingdao Jiaozhou Bay Subsea Tunnel, China. The evaluation results are in good agreement with the test results on the site, which shows that the evaluation model is feasible in this field, providing a powerful tool for systematically evaluating the grouting effects of water-rich fault in tunnels.
Zhang, You-Gai,Shi, Jian-Xiang,Song, Chun-Hua,Wang, Peng,Dai, Li-Ping,Zhang, Jian-Ying,Shi, Jia-Chen Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4
Meta-analyses have shown that microRNA polymorphisms have variable effects in different population. Yet, no meta-analysis investigated the association of two common polymorphisms of miRNA, mir-499 rs3746444 polymorphism and mir-149 rs2292832 polymorphism, with cancer risk in the Chinese population. We searched the PubMed, Web of Knowledge, MEDLINE, CNKI databases, as well as Cochrane library, updated on December 31, 2012 for assays regarding cancer risk association with these two common polymorphisms in the present meta-analysis. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were used to explore the strength of associations. The results showed that rs3746444 polymorphism was associated with increased cancer risk (dominant model: GG/AG vs. AA: OR = 1.43, 95% CI: 1.14-1.80; recessive model: GG vs. AG/AA: OR = 1.54, 95% CI: 1.04-2.30; homozygote model: GG vs. AA: OR = 1.69, 95% CI: 1.10-2.60; heterozygote model: AG vs. AA: OR = 1. 35, 95% CI: 1.09-1.67), and rs3746444 was associated with liver cancer in the subgroup of cancer types. For the rs2292832 polymorphism, the results showed no significant risk association in both overall pooled analysis and subgroup of cancer types, smoking status, gender and tea drinking status in the Chinese population. This meta-analysis suggested that the rs3746444 GG genotype is associated with increased cancer risk, especially liver cancer, while the rs2292832 polymorphism showed no association with cancer risk in Chinese.
Discrete Poisson Noise Logging Image Repair Based on Schatten Matrix Operator
Zhang Jian,Yang Jie,Zhang bin 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.3
In order to solve the problem that the present logging image reconstruction algorithm has certain staircase effect and ring effect during the discrete Poisson noise image repair process, a noise reduction algorithm based on Schatten matrix operator for discrete Poisson logging image is proposed in this article. Specifically, Schatten norm matrix of Hessian operator is adopted to estimate each pixel value of the image, and meanwhile the non-quadratic regularization function is adopted to eliminate the staircase effect; then Poisson measurement model is integrated with Schatten regularization function to construct the minimum objective function; then norm proximal mapping estimation algorithm is defined and is adopted to decouple the data fidelity item and the regularization matrix in the objective function, thus to recover the image. The simulation result shows: compared with present denoising technology, the algorithm proposed in this article has better repair effect and greater similarity in the aspect of processing the discrete Poisson noise.
Object Recognition System of Sonar Image Based on Multiple Invariant Moments and BP Neural Network
Jianning Han,Peng Yang,Lu Zhang 보안공학연구지원센터 2014 International Journal of Signal Processing, Image Vol.7 No.5
Object Recognition System of Sonar Image plays an important role in the field of underwater defense According to pattern recognition theory, principle processes of a typical object recognition system is introduced . To achieve robust performance, image de-noising, sharpening, binary transformation, edge detection and other image processing techniques are discussed . The paper presents a novel object recognition system using multiple invariant moments as the main feature of the object, and the detected feature is trained by BP neural network so that the classification error can be minizied. Finally, we implemented the proposed approach by visual air plane recognition, the experimental results demonstrates the robustness and efficiency of the presented approach.
ROOM-TEMPERATURE FERROMAGNETISM IN SnO 2 NANOFIBERS AND NANOTUBES PREPARED BY ELECTROSPINNING
JIAN-GUO ZHAO,WEI-YING ZHANG,ZHAO-JUN LIU,ZHONG-LI LIU,YA-JUAN ZHANG,ER-QING XIE,XIU-YUN AN,YONG-FENG CHEN,CHANG-YOU ZHANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.2
SnO 2 nano¯bers and nanotubes were synthesized by electrospinning method. Magnetizationmeasurement indicates that the SnO 2 nano¯bers and nanotubes annealed in air at 500?C exhibitthe room-temperature ferromagnetism and the ferromagnetism of nanotubes is stronger than thenano¯bers. Selected area electron di®raction, X-ray di®raction and Raman measurements showthat all the samples possess a typical rutile structure and no other impurity phases are observed. The results of the Raman spectra also indicate that there are lots of defects existing in thefabricated samples. The observed room-temperature ferromagnetism in SnO 2 nano¯bers andnanotubes possibly originates from oxygen vacancies. The ¯eld cooled (FC) and zero-¯eld-cooled(ZFC) magnetization curves indicate that the Curie temperature T C is above 300 K.
Zhang, Zhi-Guo,Li, Gang,Feng, Da-Yun,Zhang, Jian,Zhang, Jing,Qin, Huai-Zhou,Ma, Lian-Ting,Gao, Guo-Dong,Wu, Lin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.1
Several recent studies have showed that the n-myc downstream regulated gene 2 (NDRG2) is a new tumor suppressor gene, and that it plays an important role in tumor suppression in several cancers or cancer cell lines. However, few studies focused on its function in neuroblastoma cells. In the present investigation, we demonstrated that NDRG2 overexpression inhibited their proliferation. Using a cDNA microarray, we found that overexpression of NDRG2 inhibited the expression of cysteine-rich protein 61 (CYR61), a proliferation related gene. From our research, CYR61 may partially hinder NDRG2-mediated inhibition of cell proliferation. Overexpression of NDRG2 resulted in accumulation of cells in the G1 phase, which was accompanied by upregulation of p21 and p27 and downregulation of CDK4 and cyclin D1. Taken together, these data indicate that NDRG2 inhibits the proliferation of neuroblastoma cells partially through suppression of CYR61. Our findings offer novel insights into the physiological roles of NDRG2 in neuroblastoma cell proliferation, and NDRG2 may prove to be effective candidate for the treatment of children with neuroblastoma.
Optimal layout of long-gauge sensors for deformation distribution identification
Jian Zhang,Qingqing Zhang,Qi Xia,Zhishen Wu 국제구조공학회 2016 Smart Structures and Systems, An International Jou Vol.18 No.3
Structural deflection can be identified from measured strains from long gague sensors, but the sensor layout scheme greatly influences on the accuracy of identified resutls. To determine the optimal sensor layout scheme for accurate deflection identification of the tied arch bridge, the method of optimal layout of long-gauge fiber optic sensors is studied, in which the characteristic curve is first developed by using the bending macro-strain curve under multiple target load conditions, then optimal sensor layout scheme with different number of sensors are determined. A tied arch bridge is studied as an example to verify the effectiveness and robustness of the proposed method for static and dynamic deflection identification.