Table of Content

31 August 2015, Volume 21 Issue 4

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Metallurgical Materials

Self-adaptive synchronization of memory interface based on training

LU Chen-hong1,2, HU Yue-li1,2, ZHOU Jun2

2015, 21(4):  393-401.  doi:10.3969/j.issn.1007-2861.2014.01.006

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Memory is a core device in system on a chip (SoC) and other electronic systems for data exchange and storage at different levels. However, memory access errors may occur due to factors such as raise of frequency, jitter, phase drift, unreasonable placement and routing. An adaptive synchronize method focusing on the training of clock signal is designed for synchronous dynamic random access memory (SDRAM) interface to enhance stability of memory access. A CPU-controlled delay circuit is used to shift the phase of SDRAM clock signal. A training program is designed to cooperate with the delay module hardware for memory interface tuning. In the training mode, CPU writes test data to the memory and reads them back, judging whether they are matching or not. Training program tunes the delay circuit according to the test results. A valid data sampling window is obtained rapidly and accurately after several iterations. Using the method, the middle of the window is calculated, which is the optimal phase drift for SDRAM clock signal and can improve stability of memory access.

Estimation of view synthesis distortion caused by depth map distortion

LI Chun-hua1,2, AN Ping1,3, ZHANG Zhao-yang1,3

2015, 21(4):  402-413.  doi:10.3969/j.issn.1007-2861.2014.03.016

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A method for estimating the virtual view image distortion caused by the depth map coding distortion is proposed. The depth map is divided into macro blocks according to the coding unit. These macroblocks are then classified into uniform macroblocks and nonuniform macroblocks according to the energy density consistency constraint. The rendered view distortion in the uniform macroblocks is estimated by a block-level frequency domain method, while that in the non-uniform macroblocks by a pixel-level time domain method. Finally, the virtual view distortion is combined with both rendered view distortions. The distortion introduced by inpainting is also computed. With a shooting parameter, it can correctly classify the macroblocks of depth map sequences acquired from different shooting conditions. Simulation results show that the proposed method can accurately estimate virtual view distortion caused by depth map distortion. It achieves effective balance between accuracy and algorithm complexity, which is important to guide 3D video (3DV) coding and rate allocation under the limited bit rate budget.

Adaptive vertical handoff algorithm in heterogeneous network

JIN Yan-liang, BAI Zhi-shu, ZHOU Xu-qin, MA Wei

2015, 21(4):  414-421.  doi:10.3969/j.issn.1007-2861.2014.05.013

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Integration of 3G networks and wireless local area networks is a trend of the next generation mobile communication. Vertical handoff is the basic requirement for convergence of different access technologies, and therefore receives much attention from the academia and industry. This paper analyzes tradition algorithms and proposes a new algorithm that can adjust parameters according to the business and network status. Simulation results show that the proposed algorithm has low blocking rate, low average time delay, and high bandwidth usage.

Scale effect on buckling of bonding materials under biaxial compression with temperature changes

LIU Liang, PENG Xiang-wu, WANG Qing-zhan, GUO Xing-ming

2015, 21(4):  422-431.  doi:10.3969/j.issn.1007-2861.2014.02.007

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The scale effect on buckling of bonding materials under biaxial compression coupled with temperature changes is studied. A developed nonlocal plate theory is applied to study the buckling behavior of the nonlocal multiple-plate model. The Navier’s approach is used to obtain exact solutions for buckling loads under simply supported boundary conditions. The effects of the scale coefficient, wave number, thickness ratio, elastic modular ratio and temperature changes on the buckling loads are investigated. It is shown that the critical buckling force may be overestimated with the classical continuum theory. The nonlocal effect is proved to be more prominent for higher buckling modes. In addition, three kinds of temperature changes are taken into account. The influence of temperature
changes on the buckling loads and the relationship with the system size are analyzed.

Numerical simulation on energy acquisition of flapping airfoil with different forms of movement

HAN Wei1, SUN Xiao-jing2

2015, 21(4):  432-443.  doi:10.3969/j.issn.1007-2861.2014.02.009

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Airfoil flapping in wind or water flow can be either propulsion or power extraction. This study uses waveform parameters to control the flapping motion. Unsteady
numerical simulation is performed to study the effect of St number, amplitude and waveform of heave pitch motion on its energy extraction efficiency. The influence of different positions of pitching axis on the power extraction efficiency is also studied. The results show that the waveform-parameter and pitching axis location have a great influence on the flapping wing for power extraction in the parameter domain. Contrarily, the influence of waveform of heave motion is limited. When St is 1.332,θ₀ is 76.3, and both β_t and  β_rare 1.13 (making the pitch waveform close to a sine wave) and 0.67 respectively, the flapping airfoil can extract power at the highest efficiency, which is 41%.

Structure and dynamics of near-limit premixed flames in narrow channels

CHEN Xiao-tong, LU Zhan-bin

2015, 21(4):  444-453.  doi:10.3969/j.issn.1007-2861.2014.01.014

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Structure and dynamics of near-limit premixed flames in narrow channels are numerically studied. The channel consists of two circular parallel plates, one of which is upward and another is downward. It is possible that the premixed flame is stable when the mixture of fuel gas and oxygen in the channel is ignited. A reaction-diffusion model is used based on the Arrhenius-type chemistry, and attention is focused on the influence of distance between two plates as well as the plate’s material and radius. There are mainly two steady solutions for a given distance between the plates, a small flame and a large flame. Linear stability analysis shows that 1D stable flames may exist in the narrow channel, but 2D stable flames do not exist. The dynamical evolution processes of 1D stable, but 2D unstable flames are studied by direct numerical simulations. It is shown that the flame drifts to the boundary as a whole or an old one splits into two new flames that drift to the boundary along the opposite direction.

Predictive analysis on shield tunnel using ultra-rapid under pass method

ZHAO Xin-wei1, MA Yong-qi1,2, TENG Li3

2015, 21(4):  454-466.  doi:10.3969/j.issn.1007-2861.2014.01.040

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Ultra-rapid under pass (URUP) is a new shield construction method. The shield machine directly excavate from surface of the beginning section to the surface of
the target location. Based on the demonstration project of Nanjing shield tunnel using the URUP method, the whole shield construction process is simulated with a three dimensional nonlinear finite element method (FEM). The ground surface subsidence, the affected area, and the final settlement of ultra-thin ground coverage and partially out of the ground in the shield process are predicted and analyzed. Comparison with the measured data shows that the calculation is reliable. The results provide useful guidance to the project, and may be used as a reference for analysis of similar projects

Solubilization amount and solubilization site of nitrobenzene in the micelle system of sodium dedocyl sulfate

FAN Yong, WANG Xin-xiu, ZHA Yi-ming, ZHANG Qian, WANG Tian-lin

2015, 21(4):  467-471.  doi:10.3969/j.issn.1007-2861.2014.01.032

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Solubilization of nitrobenzene in the sodium dedocyl sulfate (SDS) micelles was investigated. It was found that the amount of nitrobenzene solubilized in SDS micelles increased with increasing concentration of both SDS and NaCl. The solubilization site of nitrobenzene in the SDS micelles was determined by nuclear magnetic resonance (NMR) near the hydrophobic core of the SDS micelles.

Distribution and ecological risk assessment of phenolic environmental hormones in Huangpu River basin

BAO Yang-yang, SUN Rui, XU Ben-tuo, XU Gang, WU Ming-hong

2015, 21(4):  472-480.  doi:10.3969/j.issn.1007-2861.2014.02.017

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Transformation and distribution characteristics of phenolic environmental hormones in 15 winter water and suspended solids samples from Huangpu River were studied. Pollution levels, spatial distributions of nonylphenol (NP), 4-t-octylphenol (4-t-OP), 4-tbutylphenol (4-t-BP) and bisphenol A (BPA) in water and suspended solids were analyzed by liquid chromatography-mass spectroscopy-mass spectroscopy (LC-MS-MS). The results showed that concentration of the above 4 phenolic environmental hormones in water and suspended solids were 167.69 ng/L with a range of 47.25356.43 ng/L, and 20.81 mg/g with a range of 2.2948.50 mg/g, respectively. The factor analysis showed that the principal pollutants were NP, 4-t-OP and BPA, with a high concentration of 4-t-BP in some
basins. Ecological risk assessment showed that hazard quotient were below 1 in the above 4 phenolic environmental hormones, and no ecological risk was found. Special attention should be paid to the potential hazard caused by algae accumulation.

Spatial distribution of PM10 in Shanghai and the influencing factors

JING Liang, XU Bin-hua, DU Yan, ZHONG Mian, FENG Jia-liang

2015, 21(4):  481-489.  doi:10.3969/j.issn.1007-2861.2014.05.003

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Daily PM₁₀ concentrations during January 2010 and December 2011 collected from 17 monitoring stations in Shanghai were analyzed together with the meteorological conditions to reveal seasonal and spatial distributions of PM₁₀. Generally speaking, homogeneous distribution of PM₁₀ concentrations between the monitoring sites was found in Shanghai, suggesting the influence of regional transport of pollutants on the air quality in Shanghai. Wind directions and speed had strong impact on the air quality in Shanghai, with higher PM₁₀ concentrations under calm and WS winds and lower concentrations under east and southeast winds. Through the analysis of the spatial distributions of the PM₁₀ concentration by plotting the deviation of PM₁₀ concentration at each site from the
averaged concentration of all sites, regular shifting of the spatial distribution of PM10 in Shanghai under different seasons and different wind directions was found. Transport of pollutants between different functional zones in Shanghai under different wind directions was responsible for the spatial variation of PM₁₀ concentration in Shanghai. Obviously lower PM₁₀ concentrations were found under low barometric pressure, but no linear correlation could be found between pressure and PM₁₀ concentration.

Synthesis of TiO2 nanospheres with large surface area for visible light synergistic catalytic degradation of Cr(VI) and bisphenol A

TRONGANH Nguyen, WANG Yu-jia, WANG Bin, CHENG Ling-li,DING Nan, JIAO Zheng

2015, 21(4):  490-502.  doi:10.3969/j.issn.1007-2861.2014.03.008

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Titanium dioxide (TiO^₂) nanospheres were successfully synthesized by sol-gel combination with hydrothermal treatment using octadecylamine template and tetrabutyl titanate precursor, and the effects of calcination temperature on the morphology of titanium dioxide. The results show that at the calcination temperature of 350 C, the prepared TiO₂ nanospheres get the best morphology and their specific surface area can reach 159.878 m²/g, three time higher than that of Degussa P25 (54.041 m²/g). Moreover, photocatalytic properties of the TiO₂ nanospheres were tested through degradation of Cr(VI) and bisphenol
A (BPA) under visible light. The results show that the TiO₂ nanospheres can effectively degrade Cr(VI) and BPA in water, and the two pollutants’ degradation has synergistic effect. In addition, TiO₂ nanospheres surface area determines its photocatalytic properties, and TiO2 nanospheres prepared under 350 C calcination conditions have optimal photocatalytic.

Influences of different fertilizer applications on nitrate accumulation in swamp cabbage and soil enzyme activity

CAO Ming-yang1, HU Xue-feng1, YAN Cheng-long1, DAI Hui-hui1,LUO Fan1, TENG Qing1, YANG Min-yong2, WANG Jian3

2015, 21(4):  503-514.  doi:10.3969/j.issn.1007-2861.2014.03.006

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To study influences of different fertilizing patterns on nitrate accumulation in swamp cabbage and soil enzyme activity, a field experiment was carried out in the suburb of Shanghai. It includes six different fertilizer treatments: no-fertilizer control; synthetic chemical fertilizer at 900, 1 800 and 2 700 kg/ha respectively; rapeseed cake manure at 2 250 and 4 500 kg/ha respectively. Content of nitrate in the vegetable and the activity of soil enzymes were analyzed throughout the growth period. The results as follows. (1) The more the applied chemical fertilizer, the higher content of nitrate is accumulated in thevegetable. The nitrate content in the vegetable has significant positive correlation with the amount of chemical fertilizer application (p<0.01). (2) During the entire growth period,
the nitrate content in the vegetable increases quickly at the beginning, reaches maximum after 21 days, then declines sharply and maintains a stable and edible range after 54 days. (3) During the latter stage of growth, activities of soil enzymes including dehydrogenase, catalase, urease and phosphatase are all significantly higher than those of the background soil, suggesting that the vegetable growth improves soil enzyme activities. Moreover, activities of soil enzymes with cake manure treatments are significantly higher than those with treatments of synthetic chemical fertilizer, suggesting that application of organic manure
can increase the enzyme activities more significantly.

Estrogen activity and toxicity effects of bisphenol A analogues on MCF-7 cells

WEN Yu, LEI Bing-li, KANG Jia, ZHANG Kai-qiong, XU Jie

2015, 21(4):  515-524.  doi:10.3969/j.issn.1007-2861.2014.04.021

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Bisphenol A (BPA) and its analogues as main raw materials for synthesis of polycarbonate are important issue of environmental pollution. Most of the current studies focus on PBA analogues’ environmental distribution and human exposure. To evaluate the cytotoxic effects of BPA analogues, MTT assay was used to assess the proliferation toxicity of 7 kinds of BPA analogues on MCF-7 (ER–), when ER is estrogen receptor. At the same time, releases of lactate dehydrogenase (LDH) escaping into cell culture medium were detected to evaluate the damage of cell membrane. The results showed that in the concentration ranges of 0.01～1.00 μmol/L, the toxic effects of tested compounds on MCF-7 cells were small and only a small amount of LDH were released. At concentrations of 10 and 100 μmol/L, cell proliferation was significantly inhibited. Permeability of cell membranewas greatly changed, and lots of LDH were released. In addition, ER gene two-hybrid yeast bioassay was used to evaluate the estrogen effects of BPA analogues. All the dose-response relationships were described by logistic function. The estrogenic activity expressed by EC50 were TDP>BPAF>4Cl-BPA>BPC>BPA>BPE>BPAP. The results shows that the
estrogenic effect mechanism is due to the binding of that target compounds and ER.