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Atmospheric Corrosion of 7B04 Aluminum Alloy in Marine Environments

  • Zhang, Xiaoyun;Liu, Ming;Lu, Feng;Liu, Minghui;Sun, Zhihua;Tang, Zhihui
    • Corrosion Science and Technology
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    • v.17 no.1
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    • pp.6-11
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    • 2018
  • Outdoor exposure tests using of 7B04 aluminium alloy samples including plate, tensile and various SCC samples were carried out in Tuandao station, Shandong province (East of China) and Wanning station, Hainan province (South of China). Corrosion characteristics including weight loss, microstructure, tensile strength and SCC susceptibility were investigated. The corrosion rates in Tuandao and Wanning showed high to low and the corrosion rates changed to the following equation of $w=at^b$ (b<1). The corrosion of 7B04 aluminium alloy in Wanning was more serious than that in Tuandao. Pitting appeared at early stage of expose test, and it can be changed to general corrosion with test time extension. The 7B04 aluminium alloy of which specimen shapes are forging and thick plate also showed SCC (Stress corrosion cracking) in the marine atmosphere. The higher SCC sensitivity was observed in Wanning station than in Tuandao station. The 7B04 aluminium alloy with a high stress level was more sensitive to SCC. Intergranular and transgranular or a mixed mode of cracking can be observed in different marine exposure.

Effect of soil-structure interaction on the reliability of hyperbolic cooling towers

  • Liao, Wen;Lu, Wenda;Liu, Renhuai
    • Structural Engineering and Mechanics
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    • v.7 no.2
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    • pp.217-224
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    • 1999
  • A semi-stochastic process model of reliability was established for hyperbolic cooling towers subjected to combined loadings of wind force, self-weight, temperature loading. Effect of the soil-structure interaction on reliability was evaluated. By involving the gust factor, an equivalent static scheme was employed to convert the dynamic model to static model. The TR combination rule was used to consider relations between load responses. An analysis example was made on the 90M cooling tower of Maoming, Guangdong of China. Numerical results show that the design not including interaction turns to be conservative.

A Study on Productivity Factors of Chinese Container Terminals

  • Lu, Bo;Park, Nam-Kyu
    • Journal of Navigation and Port Research
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    • v.34 no.7
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    • pp.559-566
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    • 2010
  • The container port industry has been variously studied by many researchers, because the contemporary container transportation and container port industries play a pivotal role in globalization of the world economy. For container terminals, the productivity, affected by many factors, is an important target in measuring container terminal performance. Under this background, finding the critical factors affecting the productivity is necessary. Regression analysis can be used to identify which independent variables are related to the dependent variable, and explore the relationships of them. The aim of paper is to evaluate the factors affecting the productivity of Chinese major terminals by using a regression statistical analysis modeling approach, which is to establish the variable preprocessing model (VPM) and regression analysis model (RAM), by means of collecting the major Chinese container terminals data in the year of 2008.

Seismic behavior of suspended building structures with semi-rigid connections

  • Liu, Yuxin;Lu, Zhitao
    • Earthquakes and Structures
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    • v.7 no.4
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    • pp.415-448
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    • 2014
  • A method is presented in this paper to analyze the dynamic response behavior of suspended building structures. The effect of semi-rigid connections that link suspended floors with their supporting structure on structural performance is investigated. The connections, like the restrains in non-structural suspended components, are designed as semi-rigid to avoid pounding and as energy dissipation components to reduce structural response. Parametric study is conducted to assess the dynamic characteristics of suspended building structures with varying connection stiffness and suspended mass ratios. Modal analysis is applied to identify the two distinct sets of vibration modes, pendulum and bearing, of a suspended building structure. The cumulative modal mass is discussed to ensure the accuracy in applying the method of response spectrum analysis by SRSS or CQC modal combination. Case studies indicate that a suspended building having semi-rigid connections and proper suspended mass ratios can avoid local pounding failure and reduce seismic response.

A Study on the Transmission-tribology Design Based on Existing Problem of the Gear Drive and Tribology

  • Lyu, Sung-Ki;Lu, Long;Wei, Yun-Long
    • International Journal of Precision Engineering and Manufacturing
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    • v.7 no.2
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    • pp.3-7
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    • 2006
  • We propose a new concept of transmission-tribology design based on the investigation of development and existing problems of the gear drive and tribology. The content of transmission-tribology and transmission-tribology design is probed. Some effective methods of transmission-tribology design is probed. Some effective methods of transmission-tribology design are put forward. Partial achievements in this research are introduced tersely. Mechanical transmission, which is represented by the gear drive, and tribology are two main branches of mechanical engineering. They have their own definite research field. In recent years, we have been doing our utmost to suggest combining mechanical transmission-tribology and transmission-tribology design. Partial achievements in this research area are obtained.

Metformin Inhibits Growth of Hepatocellular Carcinoma Cells by Inducing Apoptosis Via Mitochondrion-mediated Pathway

  • Xiong, Yu;Lu, Qing-Jun;Zhao, Jing;Wu, Guo-Yang
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.7
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    • pp.3275-3279
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    • 2012
  • Recently, population-based studies of type 2 diabetes patients have provided evidence that metformin treatment is associated with a reduced cancer incidence and mortality, but its mode of action remains unclear. Here we report effects of metformin on hepatocellular carcinoma (HCC) Hep-G2 cells and details of molecular mechanisms of metformin activity. Our research indicates that metformin displays anticancer activity against HCC through inhibition of the mTOR translational pathway in an AMPK-independent manner, leading to G1 arrest in the cell-cycle and subsequent cell apoptosis through the mitochondrion-dependent pathway. Furthermore, we showed that metformin strongly attenuated colony formation and dramatically inhibited Hep-G2 tumor growth in vivo. In conclusion, our studies suggested that metformin might have potential as a cytotoxic drug in the prevention and treatment of HCC.

Deflection prediction for reinforced concrete deep beams

  • Lu, Wen-Yao;Hwang, Shyh-Jiann;Lin, Ing-Jaung
    • Computers and Concrete
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    • v.7 no.1
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    • pp.1-16
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    • 2010
  • A simplified method, developed from the softened strut-and-tie model, for determining the mid-span deflection of deep beams at ultimate state is proposed. The mid-span deflection and shear strength predictions of the proposed model are compared with the experimental data collected from 70 simply supported reinforced concrete deep beams, loaded with concentrated loads located at a distance a from an end reaction. The comparison shows that the proposed model can accurately predict the mid-span deflection and shear strength of deep beams with different shear span-to-depth ratios, different concrete strengths, and different horizontal and vertical hoops.

Detecting smartphone user habits using sequential pattern analysis

  • Lu, Dang Nhac;Nguyen, Thu Trang;Nguyen, Thi Hau;Nguyen, Ha Nam;Choi, Gyoo Seok
    • International Journal of Internet, Broadcasting and Communication
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    • v.7 no.1
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    • pp.20-22
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    • 2015
  • Recently, the study of smart phone user habits has become a highly focused topic due to the rapid growth of the smart phone market. Indeed, sequential pattern analysis methods were efficiently used for web-based user habit mining long time ago. However, by means of simulations, it has been observed that these methods might fail for smart phone-based user habit mining. In this paper, we propose a novel approach that leads to a considerably increased performance of the traditional sequential pattern analysis methods by reasonably cutting off each chronological sequence of user logs on a device into shorter ones, which represent the sequential user activities in various periods of a day.

Metal-Ion Interactions with Sugars. The Crystal Structure of CaCl2-Fructose Complex

  • Guo, Jianyu;Lu, Yan;Whiting, Roger
    • Bulletin of the Korean Chemical Society
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    • v.33 no.6
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    • pp.2028-2030
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    • 2012
  • The single-crystal structure of $CaCl_2{\cdot}2C_6H_{12}O_6{\cdot}3H_2O$ was determined with Mr=525.34, a=16.054(7) ${\AA}$, b=7.864(4) ${\AA}$, c=10.909(5) ${\AA}$, ${\beta}=127.894(8)^{\circ}$, V=1086.9(9) ${\AA}^3$, C2, Z=2 and $R$=0.0227 for 1727 observed reflections. The fructose moiety of the complex exists as a ${\beta}$-D-pyranose. The calcium ion is surrounded by eight oxygen atoms, These are arranged in symmetry-related pairs derived from four sugar and two water molecules. Three nonvicinal hydroxyl groups of fructose are involved in calcium binding. All the hydroxyl groups and water molecules are involved in forming an extensive hydrogen-bond network.

Structure Study of Polycrystalline $Na_3YSi_3O_9$ and Its Substitutes Related to $Na_4CaSi_3O_9,\;Ca_3Al_2O_6$ Structure

  • Kim, Chy-Hyung;Banks, Ephraim
    • Bulletin of the Korean Chemical Society
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    • v.8 no.1
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    • pp.6-9
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    • 1987
  • The study of the $Na_3YSi_3O_9$ structure, by x-ray diffraction and infrared spectrum, showed that $Na_3YSi_3O_9$ is similar to $Na_4CaSi_3O_9$ except for its being pseudo-cubic instead of cubic. The peaks in the x-ray diffraction pattern of $Na_3YSi_3O_9$ could therefore be indexed on the basis of the $Na_4CaSi_3O_9$ cell. Also, modified $Na_3MSi_3O_9$ (M = Lu, Yb, Tm, Er, Y, Ho, Dy, Gd, Eu, and Sm) type compounds were synthesized by introducing excess sodium, decreasing M(III) concentration, and substituting small amount of phosphorus for silicon. The unit cell parameters of the composition $Na_{3.2}M_{0.7}Si_{2.9}P_{0.1}O_{8.7}$ were estimated from x-ray powder diffraction patterns using the Cohen method.