http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Experimental and numerical studies of aerodynamic forces on vehicles and bridges
Han, Yan,Hu, Jiexuan,Cai, C.S.,Chen, Zhengqing,Li, Chunguang Techno-Press 2013 Wind and Structures, An International Journal (WAS Vol.17 No.2
An accurate identification of the aerodynamic characteristics of vehicles and the bridge is the premise for the coupled vibration analysis of a wind-vehicle-bridge system. At present, the interaction of aerodynamic forces between the road vehicles and bridge is ignored in most previous studies. In the present study, an experimental setup was developed to measure the aerodynamic characteristics of vehicles and the bridge for different cases in a wind tunnel considering the aerodynamic interference. The influence of the wind turbulence, the wind speed, the vehicle interference, and the vehicle position on the aerodynamic coefficients of vehicles, and the influence of vehicles on the static coefficients of the bridge were investigated, based on the experimental results. The variations in the aerodynamic characteristics of vehicles and the bridge were studied and the measured results were validated according to the results of surface pressure measurements on the vehicle and the bridge. The measured results were further validated by comparing the measured results with values derived numerically. The measured results showed that the wind turbulence, the vehicle interference, and the vehicle position significantly affected the aerodynamic coefficients of vehicles. However, the influence of the wind speed on the aerodynamic coefficients of the studied vehicle is small. The static coefficients of the bridge were also significantly influenced by the presence of vehicles.
Li Li,Xiaodong Yin,Hai Meng,Juanyu Hu,Zhengqing Yu,Jianyong Xu 연세대학교의과대학 2020 Yonsei medical journal Vol.61 No.1
Purpose: The purpose of this study was to assess the diagnostic and prognostic value of serum progastrin-releasing peptide(ProGRP) in patients with gastric cancer (GC). Materials and Methods: A total of 150 patients with GC (89 males and 61 females) were recruited, including those with stage I(n=28), stage II (n=33), stage III (n=50), and stage IV (n=39) disease; 50 healthy controls and 66 patients with benign gastric diseaseswere also enrolled. Levels of serum ProGRP, carcinoembryonic antigen (CEA), and carbohydrate antigen 72-4 (CA72-4)were measured in all subjects. Results: Serum ProGRP levels were significantly higher in GC patients than in controls (p<0.001), and ProGRP was significantlycorrelated with tumor size, tumor node metastasis stage, differentiation, invasion depth, and lymph node metastasis (p< 0.005). ProGRP levels were significantly decreased after chemotherapy (p<0.001). Receiver operating characteristic curves revealed a sensitivityand specificity for serum ProGRP in GC of 85.9% and 81.2%, respectively. ProGRP levels were positively correlated withCA72-4 and CEA (r=0.792 and 0.688, p<0.05, respectively). Combined detection of ProGRP, CEA, and CA72-4 showed the best diagnosticpower for GC. Conclusion: ProGRP may be useful as a potential biomarker for GC diagnosis and therapy.
Experimental and numerical studies of aerodynamic forces on vehicles and bridges
Yan Han,C.S. Cai,Jiexuan Hu,Zhengqing Chen,Chunguang Li 한국풍공학회 2013 한국풍공학회지 Vol.17 No.2
An accurate identification of the aerodynamic characteristics of vehicles and the bridge is the premise for the coupled vibration analysis of a wind-vehicle-bridge system. At present, the interaction of aerodynamic forces between the road vehicles and bridge is ignored in most previous studies. In the present study, an experimental setup was developed to measure the aerodynamic characteristics of vehicles and the bridge for different cases in a wind tunnel considering the aerodynamic interference. The influence of the wind turbulence, the wind speed, the vehicle interference, and the vehicle position on the aerodynamic coefficients of vehicles, and the influence of vehicles on the static coefficients of the bridge were investigated, based on the experimental results. The variations in the aerodynamic characteristics of vehicles and the bridge were studied and the measured results were validated according to the results of surface pressure measurements on the vehicle and the bridge. The measured results were further validated by comparing the measured results with values derived numerically. The measured results showed that the wind turbulence, the vehicle interference, and the vehicle position significantly affected the aerodynamic coefficients of vehicles. However, the influence of the wind speed on the aerodynamic coefficients of the studied vehicle is small. The static coefficients of the bridge were also significantly influenced by the presence of vehicles.
The behavior of lightweight aggregate concrete filled steel tube columns under eccentric loading
Elzien Abdelgadir,Ji Bohai,Fu Zhongqiu,Hu Zhengqing 국제구조공학회 2011 Steel and Composite Structures, An International J Vol.11 No.6
This paper consists of two parts; the first part describes the laboratory work concerning the behavior of lightweight aggregate concrete filled steel tubes (LACFT). Based on eccentricity tests, fifty-four specimens with different slenderness ratios (L/D= 3, 7, and 14) were tested. The main parameters varied in the test are: load eccentricity; steel ratio; and slenderness ratio. The standard load-strain curves of LACFT columns under eccentric loading were summarized and significant parameters affecting LACFT column's bearing capacity, failure mechanism and failure mode such as confinement effect and bond strength were all studied and analyzed through the comparison with predicted strength of concrete filled steel tube columns (CFT) using the existing codes such as AISC-LRFD (1999), CHN DBJ 13-51-2003 (2003) and CHN CECS 28:90 (1990). The second part of this paper presents the results of parametric study and introduces a practical and accurate method for determination of the maximum compressive strength of confined concrete core ( fmax), In addition to, the study of the effect of aspect-ratio and length-width ratio on the yield stress of steel tubes ( fsy) under biaxial state of stress in CFT columns and the effect of these two factors on the ultimate load carrying capacity of axially loaded CFT/LACFT columns.