Wavelet-transform-based damping identification of a super-tall building under strong wind loads

An Xu,Jiurong Wu,Ruohong Zhao 한국풍공학회 2014 Wind and Structures, An International Journal (WAS Vol.19 No.4

A new method is proposed in this study for estimating the damping ratio of a super tall building under strong wind loads with short-time measured acceleration signals. This method incorporates two main steps. Firstly, the power spectral density of wind-induced acceleration response is obtained by the wavelet transform, then the dynamic characteristics including the natural frequency and damping ratio for the first vibration mode are estimated by a nonlinear regression analysis on the power spectral density. A numerical simulation illustrated that the damping ratios identified by the wavelet spectrum are superior in precision and stability to those values obtained from Welch’s periodogram spectrum. To verify the efficiency of the proposed method, wind-induced acceleration responses of the Guangzhou West Tower (GZWT) measured in the field during Typhoon Usagi, which affected this building on September 22, 2013, were used. The damping ratios identified varied from 0.38% to 0.61% in direction 1 and from 0.22% to 0.59% in direction 2. This information is expected to be of considerable interest and practical use for engineers and researchers involved in the wind-resistant design of super-tall buildings.

Effects of Aqueous Extract of Schizandra Chinensis Fruit on Cadmium-Induced Change of Monoamine Neurotransmitters in Rats

Zhao, Zheng Lin,Zhao, Guang Wen,Li, Li,Li, Meng Quan,Guan, Li Xin,Yang, Xu Dong,Li, Hou Zhong,Lin, Feng,Lee, Jong-Rok,Zhao, Rong Jie Korean Society of ToxicologyKorea Environmental Mu 2009 Toxicological Research Vol.26 No.1

The effects of aqueous extract of Schizandra Chinensis Fruit (AESC) on cadmium-induced changes of monoamine neurotransmitters in the different brain regions of adult rats were investigated. Male rats were received intraperitoneal (i.p.) administration of CdCl2 (0.6 mg/kg/d) for 21 days and sacrificed 7 days after the last administration. Concentrations of norepinephrine (NE), dopamine (DA) in striatum and serotonin (5-HT), 5-hydroxyindole acetic acid (5-HIAA) in cortex were measured by HPLC. There were significant decreases of NE, DA, 5-HT and 5-HIAA in Cd intoxicated rats (P < 0.05), while pretreatment with AESC (20 mg/kg/d or 60 mg/kg/d, p.o., 30 min before $CdCl_2$) greatly inhibited the decrease of monoamine transmitters, respectively (P < 0.05). Also, AESC significantly increased the reduction of glutathione contents and superoxide dismutase activities in cortex induced by $CdCl_2$. These results suggest that AESC ameliorates Cd-induced depletion of monoamine neurotransmitters in brain through its antioxidant activity.

Refolding Behavior of Urea-Induced Denaturation Collagen

Xu Wei,Yanqiu Zhao,Jingjing Zheng,Qin Cao,Sheng Li,Lang He,Benmei Wei,Juntao Zhang,Chengzhi Xu,Haibo Wang 한국고분자학회 2021 Macromolecular Research Vol.29 No.6

Exploration of the denaturation and refolding of natural collagen is important for the application of collagen and its denatured products. In this study, using urea as a denaturant, we prepared a denatured natural collagen product and analyzed its structural changes. The denaturation treatment severely destroyed the triple helix conformation of collagen, but had no significant effect on the primary structure of its α chains or the covalent cross-linking between α chains. Next, we observed the refolding behavior of the denatured collagen by removing urea through dialysis. We found that the denatured collagen products from different sources (grass carp skin, bovine tendon) all showed a reconstruction of the triple helix conformation up to 60-75% of the value of natural collagen during the refolding process. The telopeptide did not significantly promote triple helix reconstruction. In conclusion, the reconstruction of the α chains did not perfectly occur in a “head-to-head, tail-to-tail” manner in refolded collagen, as each α chain was participating in the reconstruction of multiple triple helix domains. The refolded collagen still had weak self-assembly ability and formed a unique network-like structure containing small interlaced and closely combined fibers, which shows favorable cell compatibility and potential applications.

Modulation of Drug Resistance in Ovarian Cancer Cells by Inhibition of Protein Kinase C-alpha (PKC-α) with Small Interference RNA (siRNA) Agents

Zhao, Li-Jun,Xu, Heng,Qu, Jun-Wei,Zhao, Wan-Zhou,Zhao, Yi-Bing,Wang, Jin-Hua Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.8

Objective: To determine whether silence of $PKC-{\alpha}$ expression by small interference RNA (siRNA) might regulate MDR1 expression and reverse chemoresistance of ovarian cancer. Methods: We measured gene and protein expression of MDR1 and $PKC-{\alpha}$ in ovarian cancer cells and assessed their correlation with cell drug resistance. We also examined whether blocking $PKC-{\alpha}$ by RNA interference (RNAi) affected MDR1 expression and reversed drug resistance in drug sensitivity tests. Results: The drug resistance cell lines, OV1228/DDP and OV1228/Taxol, had higher gene and protein expression of MDR1 and $PKC-{\alpha}$ than their counterpart sensitive cell line, OV1228. SiRNA depressed $PKC-{\alpha}$ gene protein expression, as well as MDR1 and protein expression and improved the drug sensitivity in OV1228/DDP and OV1228/Taxol cells. Conclusion: These results indicated that decreasing $PKC-{\alpha}$ expression with siRNA might be an effective method to improve drug sensitivity in drug resistant cells with elevated levels of $PKC-{\alpha}$ and MDR1. A new siRNA-based therapeutic strategy targeting $PKC-{\alpha}$ gene could be designed to overcome the chemoresistance of ovarian cancer.

Study on fatigue life and mechanical properties of BRBs with viscoelastic filler

Zhao-Dong Xu,Jun Dai,Qian-Wei Jiang 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.26 No.2

In this paper, two kinds of buckling restrained braces (BRBs) are designed to improve the mechanical properties and fatigue life, the reserved gap and viscoelastic filler with high energy dissipation capacity are employed as the sliding element, respectively. The fatigue life of BRBs considering the effect of sliding element is predicted based on Manson-Coffin model. The property tests under different displacement amplitudes are carried out to evaluate the mechanical properties and fatigue life of BRBs. At last, the finite element analysis is performed to study the effects of the gap and viscoelastic filler on mechanical properties BRBs. Experimental and simulation results indicate that BRB employed with viscoelastic filler has a higher fatigue life and more stable mechanical property compared to BRB employed with gap, and the smaller reserved gap can more effectively improve the energy dissipation capacity of BRB.

Subjectivity of Documentary and Cultural Diversity - A Case Study of “Victoria Wood’s Nice Cup of Tea”

Zhao-Yi Xu,Won-Ho Choi 한국콘텐츠학회 2021 한국콘텐츠학회 ICCC 논문집 Vol.2021 No.12

Establishment and validation of five autophagy-related signatures for predicting survival and immune microenvironment in glioma

Zhao Zijun,Wu Yue,Wang Zairan,Xu Jiayi,Wang Yizheng,Zhao Zongmao 한국유전학회 2022 Genes & Genomics Vol.44 No.1

Background: Gliomas, especially Glioblastoma multiforme, are the most frequent type of primary tumors in central nervous system. Increasing researches have revealed the relationship between autophagy and tumor, while the molecular mechanism of autophagy in glioma is still rarely reported. Objective: Our research aims to conform the autophagy-related genes (ARGs) implicated in the development and progression of glioma and improve our understanding of autophagy in glioma. Methods: 20 candidate ARGs were screened through the protein-protein interaction network. We also downloaded the publicly accessible glioma data for 665 individuals from TCGA and 970 individuals from CGGA with RNA sequences and clinicopathological information. Subsequently, univariate and multivariate Cox regression analysis identified 5 key ARGs among the 20 candidate genes as key prognostic genes for survival, GSEA and immune response analysis. Results: ATG5, BCL2L1, CASP3, CASP8, GAPDH were identified as key ARGs in our research. Further studies showed that the high-risk population was linked to a dismal prognosis and suggested an immune-inhibitory microenvironment. GSEA results demonstrated that high risk population was closely related to DNA repair, hypoxia pathways, implicated in immunosuppression and carcinogenesis. Through CMap, we finally identified 14 candidate drugs for the ARG high risk population. Conclusions: This study established and verified an ARG risk model, which can serve as an independent predictor for prognosis, reflect on the strength of the immune response and predict the potential drugs in glioma. Our findings offer new understandings of ARG molecular mechanism and promising therapeutic targets for glioma treatment.

Synthesis and characterization of monodisperse yttrium aluminum garnet (YAG) micro-crystals with rhombic dodecahedron

Xu, Tao,Yuan, Rui,Xu, Peng-Cheng,Pan, Dong-Jie,Yang, Woochul,Guo, Hai-Bo,Shen, Yu-Fang,Hu, Jian-Feng,Zhang, Zhi-Jun,Zhao, Jing-Tai Elsevier 2018 Journal of alloys and compounds Vol.762 No.-

<P><B>Abstract</B></P> <P>Uniform, monodisperse yttrium aluminum garnet (YAG) rhombic dodecahedron micro-crystals were synthesized using coprecipitation and hydrothermal methods. The Na<SUB>2</SUB>SO<SUB>4</SUB> as a surfactant was helpful in improving the dispersity of the crystallites and forming well-faceted, micro-sized dodecahedral YAG crystallites. The effect of the reaction time and the solvent has also been studied. The crystal growth mechanism called dissolution/crystallization was determined by analyzing the experimental and simulated results. And the specific well-developed crystal facets in the {110} family have been demonstrated by the theoretical calculation. A higher integrated emission intensity can be achieved for the YAG:Ce crystallites by improving the phase purity, morphology with better developed dodecahedrons, and dispersion. Furthermore, a rather high luminous efficacy (LE = 104.14 lm/W) for the white LED fabricated using the YAG:Ce<SUP>3+</SUP> phosphor prepared in this work was realized. The correlation between the crystal growth, morphology and luminescence properties of YAG crystallites has been established, which exhibits a great importance for the synthesis and application of mono-dispersed YAG crystallites.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Uniform and monodisperse YAG rhombic dodecahedron micro-crystals were synthesized. </LI> <LI> The growth mechanism of YAG rhombic dodecahedron was studied through experimental and computational simulation. </LI> <LI> The correlation between the crystal growth, morphology and luminescence of YAG crystallites was established. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Safety analysis of marine nuclear reactor in severe accident with dynamic fault trees based on cut sequence method

Zhao Fang,Zou Shuliang,Xu Shoulong,Wang Junlong,Xu Tao,Tang Dewen 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.12

Dynamic fault tree (DFT) and its related research methods have received extensive attention in safety analysis and reliability engineering. DFT can perform reliability modelling for systems with sequential correlation, resource sharing, and cold and hot spare parts. A technical modelling method of DFT is proposed for modelling ship collision accidents and loss-of-coolant accidents (LOCAs). Qualitative and quantitative analyses of DFT were carried out using the cutting sequence (CS)/extended cutting sequence (ECS) method. The results show nine types of dynamic fault failure modes in ship collision accidents, describing the fault propagation process of a dynamic system and reflect the dynamic changes of the entire accident system. The probability of a ship collision accident is 2.378 109 by using CS. This failure mode cannot be expressed by a combination of basic events within the same event frame after an LOCA occurs in a marine nuclear reactor because the system contains warm spare parts. Therefore, the probability of losing reactor control was calculated as 8.125 106 using the ECS. Compared with CS, ECS is more efficient considering expression and processing capabilities, and has a significant advantage considering cost.

Research on the IFC Based Data Flow of OA System for Construction Projects

Zhao Xu,Xiayan Xu,Nan Chen 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.8

Building information model (BIM) has become the mainstream in the contemporary architecture industry, which can integrate all construction project information during the life cycle, including all stages such as the survey, design, construction, delivery, use, operation, maintenance and so on. For BIM, IFC is a commonly used format which is an oriented file format with a data model to facilitate interoperability in the building industry. Besides, OA system is an efficient manager for information data while IFC standard is a kind of data expression standard for construction products. With data flow-oriented design of OA system based on IFC, the management and application of IFC data with large number and complex structure are easily worked out, which makes sharing and utilization of resources during life cycle more efficient. This article deals with a detailed analysis of the IFC data format. According to the general principle of data flow-oriented design of OA system, the framework of data flow-oriented design based on IFC is proposed, as well as the framework of storage module and the extension method of the data dictionary based on IFC, which brings great convenience for model and big data management of enterprises.