Insight into coupled forced vibration method to identify bridge flutter derivatives

Fuyou Xu,Xuyong Ying,Zhe Zhang 한국풍공학회 2016 Wind and Structures, An International Journal (WAS Vol.22 No.3

The flutter derivatives of bridge decks can be efficiently identified using the experimentally and/or numerically coupled forced vibration method. This paper addresses the issue of inherent requirement for adopting different frequencies of three modes in this method. The aerostatic force components and the inertia of force and moment are mathematically proved to exert no influence on identification results if the signal length (t) is integer (n=1,2,3...) times of the least common multiple (T) of three modal periods. It is one important contribution to flutter derivatives identification theory and engineering practice in this study. Therefore, it is unnecessary to worry about the determination accuracy of aerostatic force and inertia of force and moment. The influences of signal length, amplitude, and frequency ratio on flutter derivative are thoroughly investigated using a bridge example. If the signal length t is too short, the extraction results may be completely wrong, and particular attention should be paid to this issue. The signal length (N>5) is strongly recommended for improving parameter identification accuracy. The proposed viewpoints and conclusions are of great significance for better understanding the essences of flutter derivative identification through coupled forced vibration method.

Investigations on coefficient of variation of extreme wind speed

Fuyou Xu,Zhe Zhang,Chunsheng Cai 한국풍공학회 2014 Wind and Structures, An International Journal (WAS Vol.18 No.6

The uncertainty of extreme wind speeds is one key contributor to the uncertainty of wind loads and their effects on structures. The probability distribution of annual extreme wind speeds may be characterized using a classical Gumbel Type distribution. The expression that establishes the relationship between the extreme wind speeds at different recurrence periods and the corresponding coefficients of variation is formulated, and its efficacy is validated. The coefficients of variation are calibrated to be about 0.125 and 0.184 according to defined Chinese and US design specifications, respectively. Based on the wind data of 54 cities in China, 49 meteorological stations in the US, 3 stations in Singapore, the coefficients span intervals of (0.1, 0.35), (0.08, 0.20) and (0.06, 0.14), respectively. For hurricanes in the US, the coefficients range approximately from 0.3 to 0.4. This convenient technique is recommended as one alternative tool for coefficient of variation analyses in the future revisions of related codes. The sensitivities of coefficients of variation for 49 meteorological stations in the US are quantified and demonstrated. Some contradictions and incompatibilities can be clearly detected and illustrated by comparing the coefficients of variation obtained with different combinations of recurrence period wind data.

Investigations on coefficient of variation of extreme wind speed

Xu, Fuyou,Cai, Chunsheng,Zhang, Zhe Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.18 No.6

The uncertainty of extreme wind speeds is one key contributor to the uncertainty of wind loads and their effects on structures. The probability distribution of annual extreme wind speeds may be characterized using a classical Gumbel Type distribution. The expression that establishes the relationship between the extreme wind speeds at different recurrence periods and the corresponding coefficients of variation is formulated, and its efficacy is validated. The coefficients of variation are calibrated to be about 0.125 and 0.184 according to defined Chinese and US design specifications, respectively. Based on the wind data of 54 cities in China, 49 meteorological stations in the US, 3 stations in Singapore, the coefficients span intervals of (0.1, 0.35), (0.08, 0.20) and (0.06, 0.14), respectively. For hurricanes in the US, the coefficients range approximately from 0.3 to 0.4. This convenient technique is recommended as one alternative tool for coefficient of variation analyses in the future revisions of related codes. The sensitivities of coefficients of variation for 49 meteorological stations in the US are quantified and demonstrated. Some contradictions and incompatibilities can be clearly detected and illustrated by comparing the coefficients of variation obtained with different combinations of recurrence period wind data.

Insight into coupled forced vibration method to identify bridge flutter derivatives

Xu, Fuyou,Ying, Xuyong,Zhang, Zhe Techno-Press 2016 Wind and Structures, An International Journal (WAS Vol.22 No.3

The flutter derivatives of bridge decks can be efficiently identified using the experimentally and/or numerically coupled forced vibration method. This paper addresses the issue of inherent requirement for adopting different frequencies of three modes in this method. The aerostatic force components and the inertia of force and moment are mathematically proved to exert no influence on identification results if the signal length (t) is integer (n=1,2,3...) times of the least common multiple (T) of three modal periods. It is one important contribution to flutter derivatives identification theory and engineering practice in this study. Therefore, it is unnecessary to worry about the determination accuracy of aerostatic force and inertia of force and moment. The influences of signal length, amplitude, and frequency ratio on flutter derivative are thoroughly investigated using a bridge example. If the signal length t is too short, the extraction results may be completely wrong, and particular attention should be paid to this issue. The signal length t=nT ($n{\geq}5$) is strongly recommended for improving parameter identification accuracy. The proposed viewpoints and conclusions are of great significance for better understanding the essences of flutter derivative identification through coupled forced vibration method.

Identification of Plasma Biomarkers in Drug-Naïve Schizophrenia Using Targeted Metabolomics

Qiao Su,Fuyou Bi,Shu Yang,Huiming Yan,Xiaoxiao Sun,Jiayue Wang,Yuying Qiu,Meijuan Li,Shen Li,Jie Li 대한신경정신의학회 2023 PSYCHIATRY INVESTIGATION Vol.20 No.9

Objective Schizophrenia (SCZ) is a severe psychiatric disorder with unknown etiology and lacking specific biomarkers. Herein, we aimed to explore plasma biomarkers relevant to SCZ using targeted metabolomics. Methods Sixty drug-naïve SCZ patients and 36 healthy controls were recruited. Psychotic symptoms were assessed using the Positive and Negative Syndrome Scale. We analyzed the levels of 271 metabolites in plasma samples from all subjects using targeted metabolomics, and identified metabolites that differed significantly between the two groups. Then we evaluated the diagnostic power of the metabolites based on receiver operating characteristic curves, and explored metabolites associated with the psychotic symptoms in SCZ patients. Results Twenty-six metabolites showed significant differences between SCZ patients and healthy controls. Among them, 12 metabolites were phosphatidylcholines and cortisol, ceramide (d18:1/22:0), acetylcarnitine, and γ-aminobutyric acid, which could significantly distinguish SCZ from healthy controls with the area under the curve (AUC) above 0.7. Further, a panel consisting of the above 4 metabolites had an excellent performance with an AUC of 0.867. In SCZ patients, phosphatidylcholines were positively related with positive symptoms, and cholic acid was positively associated with negative symptoms. Conclusion Our study provides insights into the metabolite alterations associated with SCZ and potential biomarkers for its diagnosis and symptom severity assessment.

Global Regulation of Plant Immunity by Histone Lysine Methyl Transferases

Lee, Sanghun,Fu, Fuyou,Xu, Siming,Lee, Sang Yeol,Yun, Dae-Jin,Mengiste, Tesfaye American Society of Plant Biologists 2016 The Plant cell Vol.28 No.7

<P>Posttranslational modification of histones modulates gene expression affecting diverse biological functions. We showed that the Arabidopsis thaliana histone methyl transferases SET DOMAIN GROUP8 (SDG8) and SDG25 regulate pep1-, flg22-, and effector-triggered immunity as well as systemic acquired resistance. Genome-wide basal and induced transcriptome changes regulated by SDG8 and/or SDG25 showed that two genes of the SDG-dependent transcriptome, CAROTENOID ISOMERASE2 (CCR2) and ECERIFERUM3 (CER3), were also required for plant immunity, establishing mechanisms in defense functions for SDG8 and SDG25. CCR2 catalyzes the biosynthesis of carotenoids, whereas CER3 is involved in the biosynthesis of cuticular wax. SDG8 and SDG25 affected distinct and overlapping global and locus-specific histone H3 lysine 4 (H3K4) and histone H3 lysine 36 (H3K36) methylations. Loss of immunity in sdg mutants was attributed to altered global and CCR2- and CER3-specific histone lysine methylation (HLM). Loss of immunity in sdg, ccr2, and cer3 mutants was also associated with diminished accumulation of lipids and loss of cuticle integrity. In addition, sdg8 and sdg25 mutants were impaired in H2B ubiquitination (H2Bubn) at CCR2, CER3, and H2Bubn regulated R gene, SNC1, revealing crosstalk between the two types of histone modifications. In summary, SDG8 and SDG25 contribute to plant immunity directly through HLM or indirectly through H2Bubn and by regulating expression of plant immunity genes, accumulation of lipids, biosynthesis of carotenoids, and maintenance of cuticle integrity.</P>

Analyses of Quantitative Precipitation Estimation (QPE)Based on erging Satellite and Rain Gauge

QI Dan,TIAN Fuyou,Zhao Xiaolin 한국기상학회 2011 한국기상학회 학술대회 논문집 Vol.2011 No.10-2

Satellite precipitation estimates are widely used to measure global rainfall on monthly, daily, and hourly timescales for studies. Near real-time satellite precipitation estimates are becoming increasingly available to the wider community. These precipitation estimates are potentially very useful for applications such as numerical weather prediction (NWP) data assimilation, now casting and flash flood warning, tropical rainfall potential, and water resources monitoring, etc. As with any observational data, it is important to understand their accuracy and limitations. This is done by verifying the satellite precipitation estimates against independent data from rain gauges. The terms evaluate and verify are used here to mean "to determine or test the truth or accuracy of the QPE (Quantitative Precipitation Estimation) product" (John E.1999) High resolution rainfall distribution map can be derived from satellite observation, and rain gauges data can give us accurate rainfall measurements at a fixed location .Combined them together, the merging of satellite precipitation estimates and rain gauge measurement is to "calibrate" satellite precipitation estimation with ground observation, so that a more accurate rainfall field can be drawn. In this paper, we use a intellective objective analysis scheme which is brought forward by LU nai-meng (2004) to accomplish the merging or called "fusing". In this study, the satellite precipitation estimation data we used to fusing is from the National Satellite Meteorological Center (NSMC) which resolution is 0.1 degree. The rain gauge data is from the National Meteorological Information Center (NMIC). Based on the hourly and daily rain gauge precipitation observations of over 30000 rain gauges and the satellite precipitation estimation products, a real-time merging system to get the QPE product is established. At last we have done a series of evaluate and verify job to test the accuracy of the QPE products.

Static and fatigue behavior of through-bolt shear connectors with prefabricated HFRC slabs

Yuliang He,Jie Zhuang,Lipu Hu,Fuyou Li,Ying Yang,Yi-qiang Xiang 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.83 No.1

Twelve push-out test specimens were conducted with various parameters to study the static and fatigue performance of a new through-bolt shear connector transferring the shear forces of interface between prefabricated hybrid fiber reinforced concrete (HFRC) slabs and steel girders. It was found that the fibers could improve the fatigue life, capacity and initial stiffness of through-bolt shear connector. While the bolt-hole clearance reduced, the initial stiffness, capacity and slippage of through-bolt shear connector increased. After the steel-concrete interface properties were improved, the initial stiffness increased, and the capacity and slippage reduced. Base on the test results, the equation of the load-slip curve and capacity of through-bolt shear connector with prefabricated HFRC slab were obtained by the regression of test results, and the allowable range of shear force under fatigue load was recommended, which could provide the reference in the design of through-bolt shear connector with prefabricated HFRC slabs.

CYCLIN-DEPENDENT KINASE8 Differentially Regulates Plant Immunity to Fungal Pathogens through Kinase-Dependent and -Independent Functions in <i>Arabidopsis</i>

Zhu, Yingfang,Schluttenhoffer, Craig M.,Wang, Pengcheng,Fu, Fuyou,Thimmapuram, Jyothi,Zhu, Jian-Kang,Lee, Sang Yeol,Yun, Dae-Jin,Mengiste, Tesfaye American Society of Plant Biologists 2014 The Plant cell Vol.26 No.10

<P>This work explores the intriguing roles of Mediator subunit CYCLIN-DEPENDENT KINASE8 (CDK8) in plant immune responses to fungal infection. CDK8 regulates jasmonate-responsive gene expression and cuticle development via interactions with MEDIATOR COMPLEX SUBUNIT25 and transcription factor WIN1, respectively, while other interactions suggest evolutionary conservation of the Mediator kinase module.</P><P>CYCLIN-DEPENDENT KINASE8 (CDK8) is a widely studied component of eukaryotic Mediator complexes. However, the biological and molecular functions of plant CDK8 are not well understood. Here, we provide evidence for regulatory functions of <I>Arabidopsis thaliana</I> CDK8 in defense and demonstrate its functional and molecular interactions with other Mediator and non-Mediator subunits. The <I>cdk8</I> mutant exhibits enhanced resistance to <I>Botrytis cinerea</I> but susceptibility to <I>Alternaria brassicicola</I>. The contributions of CDK8 to the transcriptional activation of defensin gene <I>PDF1.2</I> and its interaction with MEDIATOR COMPLEX SUBUNIT25 (MED25) implicate CDK8 in jasmonate-mediated defense. Moreover, CDK8 associates with the promoter of <I>AGMATINE COUMAROYLTRANSFERASE</I> to promote its transcription and regulate the biosynthesis of the defense-active secondary metabolites hydroxycinnamic acid amides. CDK8 also interacts with the transcription factor WAX INDUCER1, implying its additional role in cuticle development. In addition, overlapping functions of CDK8 with MED12 and MED13 and interactions between CDK8 and C-type cyclins suggest the conserved configuration of the plant Mediator kinase module. In summary, while CDK8’s positive transcriptional regulation of target genes and its phosphorylation activities underpin its defense functions, the impaired defense responses in the mutant are masked by its altered cuticle, resulting in specific resistance to <I>B. cinerea</I>.</P>