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Table of Content

    30 June 2018, Volume 24 Issue 3
    Precision and Translational Medicine
    Interpretation of 2017 American Guideline for Hypertension in Adults
    PAN Xin, XU Yawei, XU Dachun
    2018, 24(3):  331-335.  doi:10.12066/j.issn.1007-2861.2003
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    On November 14, 2017, American College of Cardiology (ACC) and American Heart Association (AHA), together with 9 other authorities, released 2017 American Guideline for Hypertension in Adults (2017ACC/AHA). The guideline no longer used the past diagnostic standard of hypertension, and it set up a new antihypertensive target. Ever since the issue of the guideline, experts and researchers around the world have been debating over the pros and cons of the new changes the guideline contains, and it can be expected that this guideline will continue to remain a controversial topic. This paper is an attempt to interpret the American guideline by taking into account the present situation in China.

    Interpretation of Portal Hypertensive Bleeding in Cirrhosis: Risk Stratification, Diagnosis and Management: 2016 Practice Guidance by the American Association for the Study of Liver Diseases
    SONG Weiping, YANG Changqing
    2018, 24(3):  336-340.  doi:10.12066/j.issn.1007-2861.2002
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    Hemorrhage resulting from high pressure of portal vein is a common complication of decompensated liver cirrhosis. Because of different courses, anatomic locations of varicose vein and complications, patients with cirrhosis need to be prudent in their choice of methods for diagnosis, treatment and prevention of rebleeding. Portal Hypertensive Bleeding in Cirrhosis: Risk Stratification, Diagnosis and Management: 2016 Practice Guidance by the American Association for the Study of Liver Diseases, which is based on a great deal of clinical data, may serve as a guideline for clinical practice in China as well. This paper, through close reading of the practice guidance, and through comparative analysis between the American guidance and that in China, hopes to shed some new light for medical practitioners on the handling of various problems connected with liver diseases.

    Research Paper
    Novel model of pedestrian detection based on Gaussian mixture model and HOG+SVM
    GONG Luming, XU Meihua, LIU Dongjun, ZHANG Fayu
    2018, 24(3):  341-351.  doi:10.12066/j.issn.1007-2861.1849
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    To improve detection rate of pedestrian detection system, a novel pedestrian detection model by combining the Gaussian mixture background model and histograms of oriented gradients (HOG) plus support vector machine (SVM) is proposed. First, foreground segmentation is done using the Gaussian mixture model (GMM) to extract moving target areas. In the recognition of pedestrians, the dimension of the HOG descriptor is reduced by resizing the size of the detecting window. In addition, an error recognition region is used to re-update the information of sample dataset to optimize the SVM classifier. Performance of this model is evaluated with the test frames randomly chosen from a video taken in a realistic scene. The results indicate that GMM and HOG+SVM can ensure accuracy and speed of detection, and limit false detection rate to 4 %. Real-time and accurate pedestrian detection in complex scenes are achieved.

    Improved softmax classifier for deep convolution neural networks and its application in face recognition
    RAN Peng, WANG Ling, LI Xin, LIU Pengwei
    2018, 24(3):  352-366.  doi:10.12066/j.issn.1007-2861.1831
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    An effective learning method by constructing a 9-layer convolution neural network structure, using the softmax regression for human face classification and identification is proposed. Taking advantage of the improved softmax classifier in the output layer, using a rectified linear unit as the activation function in the hidden layer and local response normalization processes in the network, the problem of vanishing gradient is well solved. Pre-trained by using a large number of face images, proper network initial weights are obtained. Experiments based on three face databases YALE, FERET and LFW-A, demonstrate that the proposed method approaches the highest recognition rate compared with other methods such as SDAEs, RRC, MPCRC, CRC and SRC.

    KMC simulation for growth of InAs/GaAs quantum dots
    CHEN Long, XU Kaiyu
    2018, 24(3):  367-377.  doi:10.12066/j.issn.1007-2861.1866
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    The kinetic Monte Carlo (KMC) model is used to simulate the initial phase of the growth of InAs quantum dots on GaAs strain relaxation substrate. The strain relaxation of GaAs substrate can be obtained by burying InAs quantum dot in the substrate. The Green's function method is used to calculate strain energy distributed in the substrate surface under different burial depths. The calculation results are applied to the growth process, in which the effects of temperature, deposition rate and buried depth on the growth are considered. Simulation results show that, by controlling the growth temperature and deposition rate, uniform and orderly distribution of 2D islands can be obtained. In addition, the greater the depth of burial, the more unfavorable to the atomic aggregation.

    Turbulent flow and heat transfer in a channel with porous media
    ZHANG Yifan, LIU Caixi, DONG Yuhong
    2018, 24(3):  378-391.  doi:10.12066/j.issn.1007-2861.1871
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    Turbulent flow and heat transfer in a channel with two parallel porous walls are reported. The Darcy-Brinkman-Forcheimer (DBF) acting model based on volume averaged hypothesis is added to the Navier-Stokes equation to simulate the flow bounded by porous media. The effects of porosity and Darcy numbers on skin-friction drag as well as Nusselt numbers are studied. The results on statistical quantities for flow field and temperature field show that the skin-friction drag decreases as the porosity becomes larger, and the Nusselt numbers may increase leading to enhancement of heat transfer efficiency when the Darcy number increases.

    Attenuation characteristics of Gaussian beams passing through a granular system
    WANG Han, ZHOU Zhewei, ZHANG Jinsong, ZHANG Jianhua, WANG Zhiliang
    2018, 24(3):  392-401.  doi:10.12066/j.issn.1007-2861.1821
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    Vacuum deposition is an essential coating process to form organic light-emitting diode (OLED) film luminescent layers. Vapor of organic polymers is treated as a spherical particle systems (granular gas). A laser beam is proposed to improve their utilization rate when casting organic polymers. The Lorenz-Mie theory is used to investigate interactions between the Gaussian beam light and granular gas. The energy is found to decay exponentially, which is affected by many factors, e.g., beam waist radius, particle size parameters or refractive index. A formula of decay law is derived and analyzed to well recover the simulated data, and is consistent with the known behaviors and relations physically.

    Gas-liquid two phase detonation properties in an engine detonation chamber
    WANG Chenchen, WENG Peifen, DING Jue, LI Jiahua, CHEN Yongjie
    2018, 24(3):  402-411.  doi:10.12066/j.issn.1007-2861.1848
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    Periodic impulse generated by detonation waves is a key for a pulse detonation engine. To simulate inhomogeneous two-phase detonation, a new two-dimensional Eulerian-Lagrangian model that includes two-way coupling between gas and droplet phases is presented. Detonation of n-heptane in air/oxygen is simulated using the high resolution monotonic upwind scheme for conservation laws (MUSCLs) scheme to study thermodynamic and dynamic properties of two phase detonation. The computed detonation wave pressure is in agreement with experimental results. Based on the fuel droplets with a smaller particle size (25 $\mu $m), the computed detonation parameters corresponding to the Chapman-Jouguet (C-J) state are close to the theoretical values. It verifies the model and the research method established in this paper. Moreover, effects of droplet sizes on the detonation process are discussed. The results show that droplet break and the evaporation domain is related to the droplet size for uniform premixing. As the initial particle size of the fuel increases, the liquid droplet breaks and the evaporation domain width increases, with linear relationship between them. When the initial particle size of the fuel is increased from 25 $\mu $m to 100 $\mu $m, the width of the reaction zone is increased by 240 %, and the peak pressure of detonation is decreased from 7.08 MPa to 5.14 MPa.

    Coupled numerical simulation on electromagnetic field, flow field and temperature field in round billet secondary cooling zone with PMO
    HAO Junli, ZHAO Jing, ZHONG Honggang, XU Zhishuai, LI Renxing, ZHAI Qijie
    2018, 24(3):  412-421.  doi:10.12066/j.issn.1007-2861.1814
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    A mathematical model that couples electromagnetic field, flow field and temperature field is established to study round billet secondary cooling zone under pulse magneto-oscillation pulse magneto oscillation (PMO) using the finite element analysis software ANSYS. Billet internal magnetic flux density, electromagnetic force and Joule heat distribution are analyzed. Distribution of the flow field and temperature field are obtained according to the coupling electromagnetic force and Joule heat. The results show that an upper and lower recirculation zone is formed since a driving electromagnetic force is generated by pulse magneto-oscillation. The flow can reduce billet center temperature. As a result, the internal temperature distribution becomes more uniform, which is beneficial to grain refinement.

    Preparation and FDTD simulation of photonic crystal thin films with angle-dependent structural color
    SHEN Chunxia, ZHANG Fangfang, HUANG Lu, MENG Qingfei, YANG Weiguang, SHI Weimin
    2018, 24(3):  422-429.  doi:10.12066/j.issn.1007-2861.1834
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    Photonic crystals with angle-dependent structural color are developed as new optically variable ink for anti-counterfeiting. The finite difference time domain (FDTD) method is used to study light-modulated characteristics of two-dimensional photonic crystals composed of circular air cylinders. Reflection spectrums of two-dimensional photonic crystals with different hole diameters and distances between holes were simulated with optical software. Two-dimensional photonic crystals with a hole diameter 800 nm, distance between holes 800 nm, depth of holes 400 nm had good angle-dependent structural color. In the experiment, a Cr-SiO$_{x}$ two-layer structure was prepared on Si substrates by magnetron sputtering. Photonic crystals were fabricated using a photolithography method. The experiment results matched the simulation results.

    Influence of straightening process on tension properties of 690 alloy heat exchange tube used in steam generator
    WANG Yongdong, CAI Zhigang, YANG Yizhong, SU Cheng, YAN Shengzhi, CAO Ping
    2018, 24(3):  430-436.  doi:10.12066/j.issn.1007-2861.1829
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    Influences of straightening process and thermal treatment on the tension properties of 690 alloy tube used in steam generators were investigated. The following influence rules have been revealed. Straightening can significantly increase the room temperature yield strength of the tube, but has little effect on tensile strength. Straightening pressure has a great influence on yield strength, while straightening speed has less impact. A higher straightening pressure makes a larger increment of yield strength. Tension property of the tube after straightening can be predicted according to the test results. The process of straightening has been shown to be stable.

    Concentration and sources of WSON in $PM_{2.5}$ in Jinhua
    ZHAO Boyang, XIANG Chenglong, CHEN Huanbing, CHANG Yi, FENG Jialiang
    2018, 24(3):  437-445.  doi:10.12066/j.issn.1007-2861.1809
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    Nitrogen-containing components account for an important part of the fine particulate matter (PM$_{2.5})$, and many of the nitrogen-containing compounds are in organic form. Nitrogen-containing organics have great potential adverse impacts on the land and water ecosystem. Seasonal PM$_{2.5}$ samples were collected from spring to autumn in 2015 in Jinhua. Concentration and seasonal variation of water-soluble organic nitrogen (WSON) in the samples were analyzed. Concentration of WSON in PM$_{2.5}$ in Jinhua ranged from 0.06 to 6.90 $\mu $g/m$^{3}$ with an average of 1.90 $\mu $g/m$^{3}$, accounted for 31 % of the water-soluble total nitrogen (WSTN). Distinct seasonal variation in the concentration of WSON was found in Jinhua, with higher concentrations in autumn and spring, and the lowest in summer. On the contrary, contribution of WSON to WSTN in summer was higher than that in other seasons. The main sources of WSON in PM$_{2.5}$ in Jinhua should be the secondary formation in the atmosphere from the nitrogen-containing precursors and biomass burning emission.

    Predicting of nonstationary downburst wind velocity based on extreme learning machines
    ZHONG Wang, LI Chunxiang
    2018, 24(3):  446-455.  doi:10.12066/j.issn.1007-2861.1838
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    Using the empirical mode decomposition (EMD) and fast ensemble empirical mode decomposition (FEEMD), respectively, a nonstationary downburst wind velocity sample can be decomposed into a series of stationary sequence sets, namely, intrinsic mode functions. Extreme learning machines based on EMD and FEEMD, referred to as the EMD-ELM and FEEMD-ELM, are proposed to forecast the training and testing sets, both partitioned to stationary sequence sets. Meanwhile, combining EMD and FEEMD with a least squares support vector machine (SVM) based on particle swarm optimization, EMD-PSO-LSSVM and FEEMD-PSO-LSSVM algorithms are obtained. Comparison of these four prediction algorithms shows that EMD-ELM and FEEMD-ELM are more accurate and efficient in predicting nonstationary downburst wind velocity, while FEEMD-ELM is the best.

    Cyclic and post-cyclic direct shear behavior of sandwich reinforcement-soil interface under different sand particle sizes
    LIU Feiyu, ZHANG Duanyang, WANG Jun
    2018, 24(3):  456-466.  doi:10.12066/j.issn.1007-2861.1826
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    With three different particle sizes of quartz sand as a part of fill material, direct shear tests, cyclic shear tests and post-cyclic direct shear tests were performed using a large-scale direct shear device under different thicknesses of sand. The results indicate that, in the direct shear and post-cyclic direct tests, peak shear stress of the interface reach a maximum value with the optimal thickness of thin sand layer under different particle sizes. The optimal thickness of thin sand layer interface increases with the increase of particle. In the cyclic shear tests, the maximum shear stress of interface also show a trend from increase to decrease with the increase of sand particle size. The peak shear stress of interface increases and the volume change decreases in the post-cyclic direct shear tests as compared to the direct shear tests.

    UVRAG deficiency exacerbates fasting-induced hepatic steatosis
    HU Xiaowen, ZHANG Shasha, AN Lin, AMBER Naz, ZHU Hongxin
    2018, 24(3):  467-476.  doi:10.12066/j.issn.1007-2861.1811
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    [Objective] Ultraviolet resistance-associated gene (UVRAG) is an autophagy-related protein with multiple functions. Previously that autophagic flux is impaired in UVRAG-deficient mice has been shown. Given that autophagy regulates lipid metabolism, the role of UVRAG in fasting-induced hepatic steatosis was sought to determined. [Methods and results] Wild type (WT) and UVARG-deficient mice were subjected to normal conditions or 24 h fasting. In normal conditions, Oil red O staining showed no difference in hepatic lipid accumulation between WT and UVRAG-deficient mice. However, UVRAG deficiency exacerbates fasting-induced hepatic lipid accumulation compared with WT controls. Real time reverse transcription-polymerize chain reaction (RT-PCR) showed that UVRAG deficiency had no effects on the expression of lipid metabolic gene including CD 36, FAS, CPT-1, PPAR and FGF 21 in normal and fasting conditions. Sterol regulatory element-binding protein 1 (SREBP-1), which was lower in the liver from UVRAG-deficient mice, was comparable between fasted UVRAG-deficient mice and WT controls. Moreover, no difference in AMPK activity was observed in the liver from WT and UVRAG-deficient mice in fasting conditions. Plasma triglyceride and free fatty acid concentration were elevated in fed and fasted UVRAG-deficient mice compared with corresponding WT controls. Plasma cholesterol concentration was not different between WT and UVRAG-deficient mice in normal and fasting conditions. UVRAG deficiency exacerbated fasting-induced reduction in plasma glucose concentration. [Conclusions] UVRAG deficiency exacerbates fasting-induced hepatic steatosis, which may be due to impaired autophagic flux and increased uptake of plasma free fatty acid.

    Effect of different Numb isoforms on proliferation and migration abilities of breast cancer cell line MCF-7
    SU Hang, WANG Baolei, LI Huashun, ZHU Chenguang
    2018, 24(3):  476-485.  doi:10.12066/j.issn.1007-2861.1822
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    Objective This study explores the role of Numb isoforms in proliferation and migration of breast cancer cells. Methods TALEN technology was used to knock out Numb gene in MCF-7 cells, and then transfected p65, p66, p71 and p72 expression vectors into these Numb-KO MCF-7 cells. On this occasion, CCK-8 proliferation assay and wound scratch assay were used to detect MCF-7 cell proliferation and migration. Results The results show that transcription activator-like effector nuclease (TALEN) is effective in knocking out Numb gene. Compared with normal MCF-7 cells, proliferation and migration abilities of Numb-KO MCF-7 cells are significantly enhanced. Numb isoform p72 inhibits proliferation of Numb-KO MCF-7 cells, and Numb isoforms p65, p66, p71 and p72 inhibit migration of Numb-KO MCF-7 cells.

    Spatial-temporal sisparities of investment efficiency in the Yangtze River Economic Belt under environmental restrictions
    WANG Linyu, YU Liying
    2018, 24(3):  486-494.  doi:10.12066/j.issn.1007-2861.1835
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    This paper establishes an accounting model of investment efficiency in the Yangtze River Economic Belt under environmental restrictions based on the sequential Malmquist-Luenberger (SML) index. From the spatial perspective, large discrepancies exist among cities in investment efficiency with technological progresses as the main source of growth. Investment efficiency of each urban agglomeration trends to rise gradually from the upper reach to the lower reach of the Yangtze. The urban agglomeration in the Yangtze Delta is significantly higher than other four agglomerations in investment efficiency, but changes in efficiency are not as ideal as that in the urban agglomerations of Chengyu area and the middle reaches of the Yangtze. Chronologically, investment efficiency of the Yangtze River Economic Belt is growing. However, the main reason of the increase is the technological advances rather than the efficiency improvement. The result of this study indicates that China's environment policies have made positive effects on the improvement of environmental problems and the change of mode of production.

    Analysis of connectivity between China and the Maritime Silk Road
    YANG Cuixiang, ZONG Kang, HU Zhihua
    2018, 24(3):  495-502.  doi:10.12066/j.issn.1007-2861.1891
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    Interconnection of a shipping network is of great significance to the development of the shipping industry and the world trade. China is the advocator of the Maritime Silk Road, and is its origin. To analyze characteristics of the Maritime Silk Road shipping network, connectivity is studied between China and the Maritime Silk Road based on maritime complex networks, relating to the degree distribution, degree centrality, closeness centrality and other indicators. Damage caused by node failure and edge failure due to disconnection of the network is studied through computer simulation.