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Xiaoxia Chen,Wuhui Lin,Xianwen He,Liangliang Feng,Kuo-Ying Wang 한국기상학회 2022 Asia-Pacific Journal of Atmospheric Sciences Vol.58 No.1
The Arctic Oscillation (AO) accounts for a large fraction of recent decadal climate trends in Northern Hemisphere (NH) high latitudes. In East Asia, an elevated AO index (AOI) was associated with warmer temperatures in middle- to high-latitude regions, colder temperatures over low-latitude regions, and elevated ozone intrusion from the stratosphere. Elevated beryllium-7 (7Be) is produced in the stratosphere. Few studies have discussed the relationship between 7Be and the AO. Here, we identify the AO signature in 7Be and lead (Pb)-210 observed at a tropical ambient monitoring site in Nanning (22.8°N, 108.5°E) during the December 2014–December 2017 period. Our results show that the 7Be and 210Pb concentrations are positively and significantly correlated with the AOI (P < 0.01). These results show that elevated 7Be and 210Pb are associated with an increase in the AOI, reflecting air masses originating from NH high latitudes and vertically from the high-latitude upper troposphere and lower stratosphere regions to tropical latitudes in East Asia. These results have been verified with ozonesonde data without seasonality and with two meteorological data sets. Our results are also confirmed by observational data over the Pacific regions. We conclude that the AO exerts impacts over the tropical regions in East Asia, and 7Be can be used as a tracer to track the impacts of the AO.
Chen, Yaya,Han, Yan,Zhang, Shifeng,Cao, Tianlin,Han, Xiaoxia,Cheung, Ray C.C. The Institute of Electronics and Information Engin 2017 Journal of semiconductor technology and science Vol.17 No.5
This paper proposes a modulator that improves the signal-to-noise and distortion ratio (SNDR) by 6 dB compared with the conventional modulator. A high pass dither shaper added to the raised modulator eliminates harmonic spurs without increasing the in-band noise floor. Moreover, a behavior-level modeling method is proposed for a 200 KHz bandwidth switch-capacitor sigma-delta digital to analog converter (SC ${\Sigma}{\Delta}DAC$). Consequently, by considering the main non-idealities in the SC ${\Sigma}{\Delta}DAC$, in contrast with the conventional SC ${\Sigma}{\Delta}DAC$, MATLAB simulation results show that the SC ${\Sigma}{\Delta}DAC$ with the proposed modulator boosts the SNDR by approximately 6 dB and the spurious free dynamic range (SFDR) by approximately 8 dB. Finally, with the circuit implemented in a $0.18{\mu}m$ CMOS process, the measurement results are also used to further validate the proposed SC ${\Sigma}{\Delta}DAC$ model.
Effect of bending stiffness on the in-plane free vibration characteristics of a cable network
Wei Chen,Zhuojie Zhang,Xiaoxia Zhen,Mingyang Li 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11
Stay cables of cable-stayed bridges are connected by cross-ties to form a cable network, or the slings of the same suspension points on a suspension bridge are connected by vibration absorbers to form a sling network. As a result, the cable network’s in-plane free vibration characteristics are different from independent, single cables. However, stay cables or slings have certain bending stiffnesses, which directly affect the cable network’s free vibration characteristics. Therefore, to clarify the real dynamic behavior of a cable network and to improve the accuracy of cable network measurements, a multi-node, cross-tied, multilayer beam analytical model that considers the bending stiffness is proposed. The system equilibrium equation is established and the free vibration frequencies and modes of the system are obtained by analytical algorithm. Then, numerical simulations and field experiments, are carried out to verify the analytical results. In addition, parameter analyses with different configurations are performed on a multilayer stay-cable network and on a double-layer sling network to study the influence of bending stiffness on the cable network’s free vibration characteristics with different parameters.
Yaya Chen,Yan Han,Tianlin Cao,Xiaoxia Han,Ray C. C. Cheung,Shifeng Zhang 대한전자공학회 2017 Journal of semiconductor technology and science Vol.17 No.5
This paper proposes a modulator that improves the signal-to-noise and distortion ratio (SNDR) by 6 dB compared with the conventional modulator. A high pass dither shaper added to the raised modulator eliminates harmonic spurs without increasing the in-band noise floor. Moreover, a behavior-level modeling method is proposed for a 200 KHz bandwidth switch-capacitor sigma-delta digital to analog converter (SC ΣΔDAC). Consequently, by considering the main non-idealities in the SC ΣΔDAC, in contrast with the conventional SC ΣΔDAC, MATLAB simulation results show that the SC ΣΔDAC with the proposed modulator boosts the SNDR by approximately 6 dB and the spurious free dynamic range (SFDR) by approximately 8 dB. Finally, with the circuit implemented in a 0.18 μm CMOS process, the measurement results are also used to further validate the proposed SC ΣΔDAC model.
Georgenia faecalis sp. nov. isolated from the faeces of Tibetan antelope
Wang Xiaoxia,Yang Jing,Huang Yuyuan,Wu Xiaomin,Wang Licheng,Han Limei,Li Sha,Li Huan,Fu Xiaoying,Chen Hai,Zhu Xiong 한국미생물학회 2020 The journal of microbiology Vol.58 No.9
Two aerobic, Gram-stain-positive, non-motile, non-sporulating coccoid strains, designated ZLJ0423T and ZLJ0321, were isolated from the faeces of Tibetan antelope (Pantholops hodgsonii). Their optimal temperature, NaCl concentration and pH for growth were 28°C, 0.5% (w/v) NaCl and pH 7.5, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains ZLJ0423T and ZLJ0321 were very similar to each other (99.8%) and had a sequence similarity of 97.0% with Georgenia satyanarayanai NBRC 107612T and Georgenia subflava CGMCC 1.12782T. Phylogenomic analysis based on 688 core genes indicated that these strains formed a clade with G. satyanarayanai NBRC 107612T and Georgenia wutianyii Z294T. The predominant cellular fatty acids were anteiso-C15:0, anteiso-C15:1 A and C16:0. The major menaquinone was MK-8(H4). The cell-wall amino acids consisted of alanine, lysine, glycine and aspartic acid, with lysine as the diagnostic diamino acid. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannosides and two unidentified lipids formed the polar lipid profile. The DNA G + C content of both isolates was 73.9 mol%. The digital DNA–DNA hybridization value between strains ZLJ0423T and ZLJ0321 was 91.2%, but their values with closely related species and other available type strains of the genus Georgenia were lower than the 70% threshold. On the basis of polyphasic taxonomic data, strains ZLJ0423T and ZLJ0321 represent a novel species within the genus Georgenia, for which the name Georgenia faecalis sp. nov. is proposed. The type strain is ZLJ0423T (= CGMCC 1.13681T = JCM 33470T).
THE GENERALIZATION OF STYAN MATRIX INEQUALITY ON HERMITIAN MATRICES
Zhongpeng, Yang,Xiaoxia, Feng,Meixiang, Chen The Korean Society for Computational and Applied M 2009 Journal of applied mathematics & informatics Vol.27 No.3
We point out: to make Hermtian matrices A and B satisfy Styan matrix inequality, the condition "positive definite property" demanded in the present literatures is not necessary. Furthermore, on the premise of abandoning positive definite property, we derive Styan matrix inequality of Hadamard product for inverse Hermitian matrices and the sufficient and necessary conditions that the equation holds in our paper.
The Generalization of Styan Matrix Inequality on Hermitian Matrices
Yang Zhongpeng,Feng Xiaoxia,Chen Meixiang 한국전산응용수학회 2009 Journal of applied mathematics & informatics Vol.27 No.3
We point out: to make Hermtian matrices A and B satisfy Styan matrix inequality, the condition “positive definite property” de- manded in the present literatures is not necessary. Furthermore, on the premise of abandoning positive definite property, we derive Styan matrix inequality of Hadamard product for inverse Hermitian matrices and the sufficient and necessary conditions that the equation holds in our paper. We point out: to make Hermtian matrices A and B satisfy Styan matrix inequality, the condition “positive definite property” de- manded in the present literatures is not necessary. Furthermore, on the premise of abandoning positive definite property, we derive Styan matrix inequality of Hadamard product for inverse Hermitian matrices and the sufficient and necessary conditions that the equation holds in our paper.
Building Cooling Load Prediction Based on Time Series Method and Neural Networks
Junhua Zhuang,Yimin Chen,Xiaoxia Shi,Dong Wei 보안공학연구지원센터 2015 International Journal of Grid and Distributed Comp Vol.8 No.4
Predicting the load in a building is essential for the optimal control of heating, ventilating and air-conditioning (HVAC) systems that use Ice Thermal Energy Storage (ITES) technology and also for cost and energy reduction of the non-storage systems. To solve the problems of the low accuracy of prediction by a single method, and most load predictions focusing on short-time prediction that cause reducing the practical significance, the application of the combined prediction method of time series and neural networks is presented in this paper. A case study shows that high accuracy is achieved by using the combined prediction model based on these two methods compared with the time series method in predicting the building load for longer time.