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.

Risk of Trastuzumab-Related Cardiotoxicity in Early Breast Cancer Patients: A Prospective Observational Study

Jian Xue,Zefei Jiang,Fan Qi,Shuanghong Lv,Shaohua Zhang,Tao Wang,Xiaozhong Zhang 한국유방암학회 2014 Journal of breast cancer Vol.17 No.4

Purpose: In the present study, we investigated the incidence ofcardiotoxicity within 5 years of trastuzumab treatment and evaluatedpotential risk factors in clinical practice. Methods: The studycohort included 415 patients diagnosed with early breast cancer(EBC). Cardiotoxicity incidence was evaluated in patients receivingtrastuzumab and those who did not. Multivariate Cox proportionalhazards regression models were used to estimate hazardratios and 95% confidence intervals of potential risk factorsfor trastuzumab-related cardiotoxicity after appropriate adjustments. Results: Incidence of cardiotoxicity in patients treatedwith trastuzumab was significantly higher than that in controls(23.7% vs. 10.8%, p<0.001). This result was adjusted for factorsthat might increase the risk of cardiotoxicity, such as historyof coronary artery diseases or the use of anthracyclines for morethan four cycles. Conclusion: Our findings indicated that treatmentwith trastuzumab was strongly associated with cardiotoxicityin EBC patients.

Carbon dispersed iron-manganese catalyst for light olefin synthesis from CO hydrogenation

Jianli Zhang,Kegong Fang,Kan Zhang,Wenhuai Li,Yuhan Sun 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.3

High performance iron-manganese catalysts dispersed with carbon to produce light olefins from CO hydrogenation were prepared by sol-gel method using citric acid as precursor. The effects of carbon content on the bulk structure, the water gas shift reaction, the chain propagation ability and the activity and selectivity of the catalysts were investigated. The results showed that the catalysts were gradually reduced during the decomposition of the precursor when calcined under pure N2. The formation of iron-manganese mixed crystallites was favored and stabilized because of the enhanced interaction of iron and manganese with increasing carbon content. During the subsequent CO hydrogenation reaction, all the catalysts showed high activity and olefin selectivity. With increasing carbon content, the water gas shift (WGS) reaction was restrained and the chain propagation ability was inhibited. Catalysts with higher carbon content showed much lighter hydrocarbon products; however, the selectivity of CH4 was almost unchanged.

Preparation and Properties of Modified Silicon-containing Arylacetylene Resin with Bispropargyl Ether

Jian Zhang,Jianxiang Huang,Xiaojiao Yu,Canfeng Wang,Farong Huang,Lei Du 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.11

A novel silicon-containing arylacetylene resin (MSAR) modified by dipropargyl ether of bisphenol A (DPBPA) and dipropargyl ether of perfluorobisphenol A (DPPFBPA) was prepared separately. The curing behaviors of modified resins, DPBPA/MSAR and DPPFBPA/MSAR, were characterized with differential scanning calorimeter (DSC). The kinetic parameters of modified resins were obtained by the Kissinger and Ozawa methods. The results of dynamic mechanical analysis (DMA) revealed that the glass transition temperature (Tg) of the cured DPBPA/MSAR reached 486 °C. According to the thermogravimetric analysis (TGA), the decomposition temperature (Td5) of the cured resins and char yield (Yc, 800 °C) decreased as the dipropargyl ether loadings increased, especially in air. With the same weight loading, thermal stability of DPBPA/MSAR was better than that of DPPFBPA/MSAR. The carbon fiber (T300) reinforced composites exhibited excellent flexural properties at room temperature with a high property retention at 300 °C.

Preparation and Properties of Modified Silicon-containing Arylacetylene Resin with Bispropargyl Ether

Zhang, Jian,Huang, Jianxiang,Yu, Xiaojiao,Wang, Canfeng,Huang, Farong,Du, Lei Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.11

A novel silicon-containing arylacetylene resin (MSAR) modified by dipropargyl ether of bisphenol A (DPBPA) and dipropargyl ether of perfluorobisphenol A (DPPFBPA) was prepared separately. The curing behaviors of modified resins, DPBPA/MSAR and DPPFBPA/MSAR, were characterized with differential scanning calorimeter (DSC). The kinetic parameters of modified resins were obtained by the Kissinger and Ozawa methods. The results of dynamic mechanical analysis (DMA) revealed that the glass transition temperature ($T_g$) of the cured DPBPA/MSAR reached $486^{\circ}C$. According to the thermogravimetric analysis (TGA), the decomposition temperature ($T_{d5}$) of the cured resins and char yield ($Y_c$, $800^{\circ}C$) decreased as the dipropargyl ether loadings increased, especially in air. With the same weight loading, thermal stability of DPBPA/MSAR was better than that of DPPFBPA/MSAR. The carbon fiber (T300) reinforced composites exhibited excellent flexural properties at room temperature with a high property retention at $300^{\circ}C$.

Synthesis of molybdenum diselenide nanosheets and its ethanol-sensing mechanism

Zhang, Shaolin,Zhang, Weibin,Nguyen, Thuy Hang,Jian, Jiawen,Yang, Woochul Elsevier 2019 Materials chemistry and physics Vol.222 No.-

<P><B>Abstract</B></P> <P>Molybdenum diselenide (MoSe<SUB>2</SUB>) nanosheets thin film gas sensor was firstly fabricated and its sensing potential to ppm-level ethanol vapor at low operating temperature was investigated. Ultrathin MoSe<SUB>2</SUB> nanosheets were prepared in large scale through a facile liquid-phase exfoliation method using low-boiling-temperature solvent. The exfoliated MoSe<SUB>2</SUB> nanosheets exhibited high purity and crystallinity with few atomic layer thickness. Systematical gas sensing tests demonstrated that MoSe<SUB>2</SUB> nanosheets based thin film could be utilized as ethanol gas sensor with linear response, quick recovery, and good repeatability at 90 °C. The sensing mechanism of MoSe<SUB>2</SUB> toward ethanol was investigated based on first principle calculation. The adsorption behavior of ethanol molecules on MoSe<SUB>2</SUB> surface was revealed in light of adsorption orientation, adsorption energy, charge transfer, projected electronic density of state, and molecular orbital. The calculation well matched with experimental results. It is found the quick and completed recovery of MoSe<SUB>2</SUB> nanosheets sensor was benefited by the appropriate physical interaction between ethanol and MoSe<SUB>2</SUB> surface. This finding offers a competitive option instead of conventional graphene sensor for ethanol gas detection at low temperature.</P>

Crystal Structure, Fluorescence Property and Theoretical Calculation of the Zn(II) Complex with o-Aminobenzoic Acid and 1,10-Phenanthroline

Zhang, Zhongyu,Bi, Caifeng,Fan, Yuhua,Zhang, Xia,Zhang, Nan,Yan, Xingchen,Zuo, Jian Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.6

A novel complex [$Zn(phen)(o-AB)_2$] [phen: 1,10-phenanthroline o-AB: o-aminobenzoic acid] was synthesized and characterized by elemental analysis and X-ray diffraction single-crystal analysis. The crystal crystallizes in monoclinic, space group P2(1)/c with $a=7.6397(6){\AA}$, $b=16.8761(18){\AA}$, $c=17.7713(19){\AA}$, ${\alpha}=90^{\circ}$, ${\beta}=98.9570(10)^{\circ}$, ${\gamma}=90^{\circ}$, $V=2.2633(4)nm^3$, Z = 4, F(000) = 1064, S = 1.058, $Dc=1.520g{\cdot}cm^{-3}$, $R_1=0.0412$, $wR_2=0.0948$, ${\mu}=1.128mm^{-1}$. The Zn(II) is six coordinated by two nitrogen and four oxygen atoms from the 1,10-phenanthroline and o-aminobenzoic acid to furnish a distorted octahedron geometry. The complex exhibits intense fluorescence at room temperature. Theoretical studies of the title complex were carried out by density functional theory (DFT) B3LYP method. CCDC: 898291.

Seismic response simulations of bridges considering shear-flexural interaction of columns

Zhang, Jian,Xu, Shi-Yu Techno-Press 2009 Structural Engineering and Mechanics, An Int'l Jou Vol.31 No.5

Bridge columns are subjected to combined actions of axial force, shear force and bending moment during earthquakes, caused by spatially-complex earthquake motions, features of structural configurations and the interaction between input and response characteristics. Combined actions can have significant effects on the force and deformation capacity of RC columns, resulting in unexpected large deformations and extensive damage that in turn influences the performance of bridges as vital components of transportation systems. This paper evaluates the seismic response of three prototype reinforced concrete bridges using comprehensive numerical models that are capable of simulating the complex soil-structural interaction effects and nonlinear behavior of columns. An analytical approach that can capture the shear-flexural interacting behavior is developed to model the realistic nonlinear behavior of RC columns, including the pinching behavior, strength deterioration and stiffness softening due to combined actions of shear force, axial force and bending moment. Seismic response analyses were conducted on the prototype bridges under suites of ground motions. Response quantities of bridges (e.g., drift, acceleration, section force and section moment etc.) are compared and evaluated to identify the effects of vertical motion, structural characteristics and the shear-flexural interaction on seismic demand of bridges.

Isolation and Preliminary Identification of a Novel Microorganism Producing Aspartame from Soil Samples

Jian Dong Cui,Ya Nan Zhang,Gui Xia Zhao,Shi Ru Jia,Guo Qun Zhao,Si Zhang,Jun Lu 한국식품과학회 2010 Food Science and Biotechnology Vol.19 No.2

To develop a new method for producing aspartame (APM), a simple and efficient strategy for the isolation of certain microorganisms producing APM from soil samples was designed. A newly strain with secreting certain specific dipeptidase to directly synthesize APM from the substrates of L-aspartic acid (L-Asp) and Lphenylalanine methyl ester (L-PM) without protection for amino acid side chains was screened from soil samples. APM concentration in reaction mixture was quantified by high performance liquid chromatography (HPLC), yield reached 0.015 g/L. Examination of the general morphological characteristics and data from the sequence analysis of the rDNA-ITS gene led to identification of the isolate as a strain of fungal endophyte spp. The newly isolated strain had a high potential for application in industrial processes for APM production. In particular, this new method was low cost for synthesis of APM during the reaction due to avoiding protection for amino acid side chains and optical resolution of the mixtures. As we known it, this is first report that a newly strain with a high potential for selective synthesis of the APM was isolated from soil.