The medium coupling effect on propagation of guided waves in engineering structures and human bone phantoms

Chen, Jiangang,Su, Zhongqing,Cheng, Li Techno-Press 2012 Coupled systems mechanics Vol.1 No.4

As a result of the medium coupling, propagation characteristics of ultrasonic waves guided by a multi-phase medium can be different from those in a homogeneous system. This phenomenon becomes prominent for a medium consisting of phases with considerably distinct material and physical properties (e.g., submerged structures or human bones covered with soft tissues). In this study, the coupling effect arising from both fluid and soft tissues on wave propagation in engineering structures and human bone phantoms, respectively, was explored and calibrated quantitatively, with a purpose of enhancing the precision of ultrasonic-wave-based non-destructive evaluation (NDE) and clinical quantitative ultrasound (QUS). Calibration results were used to rectify conventional NDE during evaluation of corrosion in a submerged aluminium plate, and QUS during prediction of simulated healing status of a mimicked bone fracture. The results demonstrated that with the coupling effect being appropriately taken into account, the precision of NDE and QUS could be improved.

Exploring and calibrating local curvature effect of cortical bone for quantitative ultrasound (QUS)

Chen, Jiangang,Su, Zhongqing,Cheng, Li,Ta, De-An Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.48 No.4

Apart from thinning of cortical layers, the local bone curvature, varying along bone periphery, modulates ultrasound waves as well, which is however often underestimated or overlooked in clinical quantitative ultrasound (QUS). A dedicated three-dimensional finite element modelling technique for cortical bones was established, for quantitatively exploring and calibrating the effect of local curvature of cortical bone on ultrasound. Using a correlation-based mode extraction technique, high-velocity group (HVG) and low-velocity group (LVG) wave modes in a human radius were examined. Experimental verification using acrylic cylinders and in vitro testing using a porcine femur were accomplished. Results coherently unravelled the cortical curvature exerts evident influence on bone-guided ultrasound when RoC/${\lambda}$ <1 for HVG mode and RoC/${\lambda}$ <2 for LVG mode (RoC/${\lambda}$: the ratio of local bone curvature radius to wavelength); the sensitivity of LVG mode to bone curvature is higher than HVG mode. It has also been demonstrated the local group velocity of an HVG or LVG mode at a particular skeletal site is equivalent to the velocity when propagating in a uniform cylinder having an outer radius identical to the radius of curvature at that site. This study provides a rule of thumb to compensate for the effect of bone curvature in QUS.

Exploring and calibrating local curvature effect of cortical bone for quantitative ultrasound (QUS)

Jiangang Chen,Zhongqing Su,Li Cheng,De-an Ta 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.48 No.4

Apart from thinning of cortical layers, the local bone curvature, varying along bone periphery,modulates ultrasound waves as well, which is however often underestimated or overlooked in clinical quantitative ultrasound (QUS). A dedicated three-dimensional finite element modelling technique for cortical bones was established, for quantitatively exploring and calibrating the effect of local curvature of cortical bone on ultrasound. Using a correlation-based mode extraction technique, high-velocity group (HVG) and low-velocity group (LVG) wave modes in a human radius were examined. Experimental verification using acrylic cylinders and in vitro testing using a porcine femur were accomplished. Results coherently unravelled the cortical curvature exerts evident influence on bone-guided ultrasound when RoC/λ<1 for HVG mode and RoC/λ<2 for LVG mode (RoC/λ: the ratio of local bone curvature radius to wavelength); the sensitivity of LVG mode to bone curvature is higher than HVG mode. It has also been demonstrated the local group velocity of an HVG or LVG mode at a particular skeletal site is equivalent to the velocity when propagating in a uniform cylinder having an outer radius identical to the radius of curvature at that site. This study provides a rule of thumb to compensate for the effect of bone curvature in QUS.

Double-layer Fabry-P$\acute{e}$rot filter interferometric modulator display

Chen, Chao Ping,Xiong, Yuan,Yang, Yuxing,Li, Xiao,Li, Hongjing,He, Gufeng,Lu, Jiangang,Su, Yikai 한국정보디스플레이학회 2013 Journal of information display Vol.14 No.4

Presented is an interferometric modulator display characterized by double layers of liquid crystal (LC) Fabry-P$\acute{e}$rot filters. With this design, no polarizers and color filters are needed, and both the color and amplitude can be tuned by electrically controlling the LC's birefringence. Instead of the conventional RGB trisubpixel color scheme, a bisubpixel structure is proposed to render a super-wide color gamut. Through simulations, the device performance was numerically studied. The device was proven to be quite suitable for green-display application.

Double-layer Fabry–Pérot filter interferometric modulator display

Chao Ping Chen,Yuan Xiong,Yuxing Yang,Xiao Li,Hongjing Li,Gufeng He,Jiangang Lu,Yikai Su 한국정보디스플레이학회 2013 Journal of information display Vol.14 No.4

Presented is an interferometric modulator display characterized by double layers of liquid crystal (LC) Fabry–Pérot filters. With this design, no polarizers and color filters are needed, and both the color and amplitude can be tuned by electrically controlling the LC’s birefringence. Instead of the conventional RGB trisubpixel color scheme, a bisubpixel structure is proposed to render a super-wide color gamut. Through simulations, the device performance was numerically studied. The device was proven to be quite suitable for green-display application.

An Investigation on the Density Wave Instability of High Pressure Steam-Water Two-Phase Flow in Vertical Parallel Pipes

Ting Kuan Chen,Jiangang Jing 대한기계학회 1998 Heat transter conference Vol.2 No.1

Experimental study on the compression of concrete filled steel tubular latticed columns with variable cross section

Yan Yang,Jun Zhou,Jiangang Wei,Lei Huang,Qingxiong Wu,Bao-chun Chen 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.22 No.3

The effects of slenderness ratio, eccentricity and column slope on the load-carrying capacities and failure modes of variable and uniform concrete filled steel tubular (CFST) latticed columns under axial and eccentric compression were investigated and compared in this study. The results clearly show that all the CFST latticed columns with variable cross section exhibit an overall failure, which is similar to that of CFST latticed columns with a uniform cross section. The load-carrying capacity decreases with the increase of the slenderness ratio or the eccentricity. For 2-m specimens with a slenderness ratio of 9, the ultimate load-carrying capacity is increased by 3% and 5% for variable CFST latticed columns with a slope of 1:40 and 1:20 as compared with that of uniform CFST latticed columns, respectively. For the eccentrically compressed variable CFST latticed columns, the strain of the columns at the loading side, as well as the difference in the strain, increases from the bottom to the cap, and a more significant increase in strain is observed in the cross section closer to the column cap.

Characterization, activity and selectivity of ethylenediamine modified Co/SiO2 FT catalyst prepared by sol-gel method

Yuelun Wang,Bo Hou,Jiangang Chen,Litao Jia,Debao Li,Yuhan Sun 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.3

Co/SiO2 catalysts were prepared by sol-gel method with varied en (ethylenediamine)/Co molar ratios under the same pH. Their physical-chemical properties were compared with those prepared with similar en/Co molar ratios at natural pH or without adding ethylenediamine. Regardless of pH, the catalysts prepared using ethylenediamine possessed high microporosity, which led to a better selectivity to C5-18 hydrocarbons, versus the catalyst possessing higher mesoporosity which showed slightly higher C18+ selectivity. As enough positions in the coordination sphere were blocked by ethanediamine ligands, the formation of cobalt silicate disfavored for (en/Co=2) catalysts, which resulted in the higher activity in FT reaction. Whereas the catalysts prepared with lower or higher en/Co molar ratio both showed lower activity due to the formation of [(SiO)Co(en)(EtOH)3] species or the electronic adsorption of cobalt complexes in the negatively charged silica surface, respectively. However, for the catalyst without using ethylenediamine, the lowest activity and the highest CH4 selectivity obtained due to its much lower reducibility.

Four New Antioxidant Phenylpropanoid Glycosides from Microlepia pilosissima

Jiang Hu,Xiaodong Shi,Jiangang Chen 대한약학회 2012 Archives of Pharmacal Research Vol.35 No.12

Four new phenylpropanoid glycosides, 9-O-[β-D-glucopyranosyl-(1→2)-α-L-rhamnopyranosyl]-3,4-dimethoxy-cinnamic acid (1), 9-O-[β-D-glucopyranosyl-(1→2)-α-L-rhamnopyranosyl]-4-methoxycinnamic acid (2), 9-O-α-L-rhamnopyranosyl-3,4-dimethoxy-cinnamic acid (3), and 9-O-[6-Oacetyl-β-D-glucopyranosyl]-4-methoxy-cinnamic acid (4), together with three known compounds 9-O-α-L-rhamnopyranosyl-4-hydroxy-cinnamic acid (5), 9-O-β-D-glucopyranosyl-4-methoxycinnamic acid (6), and 9-O-β-D-glucopyranosyl-3,4-dimethoxy-cinnamic acid (7) were isolated from the 70% EtOH extract of the dry fronds of Microlepia pilosissima. Their chemical structures were elucidated by spectroscopic analysis. Moreover, 1 and 2 exhibited comparable scavenging activities with (±)-α-tocopherol against DPPH radicals, while compounds 3-7 displayed moderate antioxidant activities.

Impact of AhR, CYP1A1 and GSTM1 Genetic Polymorphisms on TP53 R273G Mutations in Individuals Exposed to Polycyclic Aromatic Hydrocarbons

Gao, Meili,Li, Yongfei,Xue, Xiaochang,Long, Jiangang,Chen, Lan,Shah, Walayat,Kong, Yu Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.6

This study was to undertaken to investigate the impacts of AhR, CYP1A1, GSTM1 genetic polymorphisms on the R273G mutation in exon 8 of the tumor suppressor p53 gene (TP53) among polycyclic aromatic hydrocarbons (PAHs) exposed to coke-oven workers. One hundred thirteen workers exposed to PAH and 82 control workers were recruited. We genotyped for polymorphisms in the AhR, CYP1A1, GSTM1, and TP53 R273G mutation in blood by PCR methods, and determined the levels of 1-hydroxypyrene as PAH exposure marker in urine using the high pressure liquid chromatography assay. We found that the distribution of alcohol users and the urinary excretion of 1-OHP in the exposed workers were significantly higher than that of the control workers (p=0.004, p<0.001, respectively). Significant differences were observed in the p53 genotype distributions of smoking subjects (p=0.01, 95%CI: 1.23-6.01) and PAH exposure (p=0.008, 95%CI: 1.24-4.48), respectively. Further, significant differences were observed in the p53 exon 8 mutations for the genetic polymorphisms of Lys/Arg for AhR (p=0.02, 95%CI: 0.70-15.86), Val/Val for CYP1A1 (p=0.04, 95%CI: 0.98-19.09) and null for GSTM1 (p=0.02, 95%CI: 1.19-6.26), respectively. Our findings indicated that polymorphisms of PAH metabolic genes, such as AhR, CYP1A1, GSTM1 polymorphisms may interact with p53 genetic variants and may contribute to PAH related cancers.