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  • Articles
    LI Yongping, SUN Yueqiang, WANG Xinyue, FU Zhenyu
    Science & Technology Review. 2019, 37(6): 104-113.
    The thermospheric neutral density sees a strong variation during equinoxes and solstices due to the solar insolation variation. The long-term continual data from Chinese Atmospheric Density Detector installed on the satellite are used to study this variation, The main results of this study are that the thermospheric density has an obvious symmetry around March equinox and September equinox; the thermosphere density has an obvious asymmetry around June solstice and December solstice; the variations have an obvious hemispheric asymmetry in high latitude (around 80 degrees); the proportion of the atmospheric density is 3~3.6 times at the height of 670 km, 13 times at the height of 560 km; the latitude and the altitude contribute to this asymmetry; the comparison of the measured data and the NRLMSISE00 data shows that the NRLMSISE00 data cannot fully respond to the summer and winter hemisphere atmospheric density variations.
  • Articles
    DONG Huijuan, WANG Jingxuan, LI Tianlong
    Science & Technology Review. 2019, 37(6): 114-128.
    Abstract (521) PDF (1448) HTML   Knowledge map   Save
    In recent years, as the scientific studies in the field of biology and medicine come down to micron or even nanometer scales, many manipulation methods of micro-nano fluids and particles have emerged, such as the optical drive, the magnetic drive and the chemical mode drive. The sound-driven method has been widely used in the micro-nano field due to its features of non-contact and biocompatibility, and has broad application prospects in the fields of biomedicine and diagnostics. This paper outlines the basic structure of the traveling acoustic surface waves (TSAW) generating device, the structure, the parameters, the types of the interdigital transducer (IDT) and the internal mechanism that causes the traveling surface acoustic waves. The acoustic control mechanism of the microfluidic state and the particles in the microfluids is discussed. Based on the current research status of the technology at home and abroad, the advantages of the traveling acoustic surface waves, as compared to other physical fields in the micro-nano field are analyzed. Finally, in view of the technical difficulties of the traveling acoustic surface waves applied in the micro-nano field and the problems existing in the research process, some research directions of the technology are proposed, and a reasonable prospect for the future development trend is suggested.
  • Articles
    LIU Guangwei, LI Changyong, PI Jian, LIU Fan, TANG Shasha
    Science & Technology Review. 2018, 36(23): 87-92.
    Based on the characteristics of the large scope permeability distribution, and the joint action of the seepage law for both low permeability and medium to high permeability, aiming at the problem of the recovery restriction for low permeability points caused by the start-up pressure, the influence of the start-up pressure gradient of low permeability points on the sweep coefficient is studied by the numerical simulations. Also, by coupling the start-up pressure gradient and the displacement pressure distribution for the low permeability point, the correction method for the sweep efficiency is established. Result shows that the lower the reservoir permeability and the higher the permeability variation, the greater the influence of the start-up pressure of the low permeability points on the sweep coefficient. Taking the M oil reservoir in the Middle East as an example, the application analysis is carried out. When the reservoir permeability is between 5~35×10-3 μm2 and the permeability variation is between 0.6~0.8, the range of the correction coefficient is about 0.75~0.99, which in turn can correct the calculation of the sweep efficiency in the industry standards.
  • Articles
    YE Xiaorong, SHAO Qing
    Science & Technology Review. 2018, 36(23): 93-101.
    In order to effectively explore the user information in large-scale social networks and improve the understanding of the relationship between users, a community detection prototype system based on Spark is designed and developed. The ActiveMQ is used to acquire a large amount of the user data, taking advantage of the naive Bayesian algorithm provided by Spark-based MLlib to clean the user data, and using the PageRank algorithm provided by Spark-based GraphX and the Z-Score algorithm provided by MLlib to calculate the user ranking. In the prototype system, the LPA algorithm is finally used and optimized, to group the users of similar features and close ties into the same community quickly, as a foundation for further analysis and utilization of the community user data.
  • Articles
    LI Chunlin, YE Fang, WANG Fen, Hyun Chul KLm, Jaepil PArk
    Science & Technology Review. 2018, 36(22): 145-151.
    The city's driving force of science and technology is the comprehensive driving factor of scientific and technological progress, and is the reason of the difference of regional science and technology. Based on the theory of innovation motivation, the paper selects 18 evaluation indexes from five aspects i.e., human support, material support, innovation preferences, demand pull and science and technology service, and uses the data from 2003 to 2012 of 11 cities in Zhejiang to analyze the dynamic change rules of the urban driving force of science and technology by means of weighting method with timing global factor analysis. The 11 cities are divided into three levels by system clustering method and three gradients by gradient analysis. The reasons of time-spacial differentiation of the city's driving force of science and technology are shown through variation analysis as innovation preferences and science and technology services.
  • Articles
    YAO Yangping, CONGYI Minxing, LUO Ting, ZHANG Xing, WANG Junbo, GENG Yi
    Science & Technology Review. 2018, 36(17): 106-110.
    A large number of airports are under construction in mountainous areas in China, to improve the local traffic conditions. However, the construction and the management of the high filling airports, built by"cutting the mountains to fill the valleys", still face many difficulties. In order to control the quality of the high filling project, a real-time monitoring system for high filling compaction is developed by using the "Internet Plus" technology. The driverless technology makes the automated intelligent construction become a reality; In order to control the settlement after the construction, a safety monitoring system in the whole life cycle is established, which can predict the long-term deformation and issue disaster warnings in advance. In order to deal with the increased water content of the shallow soils under the airport runway, known as the pot effect, both laboratory and field experiments are conducted to trace the causes. Meanwhile, an effective engineering measure is proposed to reduce the pot effect by laying the insulating layer below the position where the soil temperature is around 0℃.
  • Articles
    LI Kuo, XU Yinlong
    Science & Technology Review. 2018, 36(15): 67-76.
    The impacts of climate change are becoming more and more remarkable. So adaptation to climate change has gradually turned into a global hotpot. Northeast China is an important base of grain production, the impact of climate change on which will directly cause fluctuations of the grain production in China. From the perspective of adaptation to climate change, the key challenges to agriculture due to climate change are analyzed. According to the analysis, four key problems are discussed, which are the increasing heat resources, the rising frequency and intensity of drought and flood disasters, the declining extreme events of low temperature and chilling, and significantly increasing plant diseases and insect pests damage. In view of the above influencing key issues, the adaptation technologies are classified into six categories, namely capital construction of farmland, selection and breeding of anti adversity varieties, tillage and cultivation of crops to cope with disasters, adjustment of planting structure, pest control, and agricultural insurance. In this paper, the key technologies of adaptation to climate change in Northeast China are identified and optimized. They and assorted technologies are assembled and integrated to form a framework of technology system adaptive to climate change. This paper may provide some theoretical guidance and technical support to the adaptation work in different regions and sectors of China to speed up the activities of adaptation to climate change.
  • Articles
    LI Tianlong, YU Hao, LI Mu, TANG Wentian, DONG Huijuan, ZHOU Dekai, LI Longqiu, ZHANG Guangyu
    Science & Technology Review. 2018, 36(15): 77-84.
    Due to lightweight, less volume and high thrust, micro/nano motors can be widely used in the fields of sensing detection, nanofabrication and experimental remediation. Especially, micro/nano motors can serve as promising biomimetic motors for biomedical and nanoelectronic applications. In this paper, fabrication, propulsion and control methods of micro/nano motors are expounded. And micro/nano motors used for the fields of targeted therapy, nano surgery, toxins adsorption and thrombolysis are summarized. Finally, the challenge and development direction of micro/nano motors used for biomedicine application are discussed.
  • Articles
    CHEN Lide
    Science & Technology Review. 2018, 36(15): 85-92.
    On the basis of reflection on existing flood control and disaster mitigation measures and based on the consideration of ‘flood and sediment resources’, the measures for flood control in Jingjiang and Jianghan-Dongting areas of the Yangtze river are proposed. These measures are ‘dreding sand, expanding the lakes and reforming cold waterlogged paddy fields’ while ‘recreating the Yunmengze and expending the Dongting-lake’, which will expand the flood storage space in Jianghan-Dongting area. Under the principle of ‘draining and raising storage with draining first’ and ‘rivers and lake confrontation’, an overall consideration on food control and disaster reduction as well as the transformation of the cold leaching fields and improvement of Schistosomiasis control work should be taken into account, so as to support the sustainable development strategy of the Yangtze river economic belt and the middle reaches of the Yangtze river.
  • Articles
    XUE Chunlei, LU Xiaoping, HAN Pingan, ZHANG Kunming, ZHANG Ruixia, DONG Jing
    Science & Technology Review. 2018, 36(14): 88-98.
    Sorghum-sudangrass hybrids are annual gramineous forage crops with intergrated excellent parental traits. Their heterosis is particularly prominent, but the molecular mechanism of the heterosis is not yet very clear. To reveal the molecular mechanism, the mature embryos of sorghum-sudangrass hybrids and their parents are analyzed by the Label free mass spectrometry and the bioinformatics methods based on proteomics in this study. 124 differentially expressed proteins are identified, among which 48 are additive accumulation proteins, accounting for 38.71% of the total proteins. 19 and 29 of them are up-regulated proteins and down-regulated proteins, respectively. 76 of them are non-additive accumulation proteins, accounting for 61.29% of the total proteins. 29 proteins are of the above-high-parent expression, with the greatest proportion among the non-additive accumulation expression patterns. Followed by the high-parent expression patterns(18 proteins), the low-parent expression patterns (14 proteins), the below-low-parent expression patterns(10 proteins). Besides, there are 5 proteins which do not belong to the above four kinds of protein expression patterns. Therefore, non-additive proteins play especially dominant roles in the heterosis of the mature embryo of sorghum-sudangrass hybrids. Additive and non-additive accumulation proteins cover multiple functional groups, which involve the stress response, the carbohydrate metabolism, the transcriptional regulation, the development regulation, the signal transduction, the protein metabolism and others.
  • Articles
    YANG Liyun, ZHANG Lanyue, DING Chenxi, SUN Jinchao, LIU Linlin, LI Ming
    Combining with the digital image correlation method and the ultra high speed photography technology, an experimental system of ultra high speed digital image correlation is set up to realize monitoring and analysis of the ultra-dynamic strain field under blasting loading. By using the experimental system and the UV flatbed printing technology, a blasting model experiment on polycarbonate (PC) plate is conducted, the evolution of blasting strain field and the attenuation law are analysed. The results show that the compressive wave is the main form of blasting stress wave and the shear wave is the minor form. With the propagation of stress wave in the specimen plane, the stress wave decays from high frequency to low frequency, and the energy of stress wave dissipates gradually. In addition, the ABAQUS finite element analysis code is used to simulate the dynamic process of blasting. The deformation evolution of numerical simulation is in good agreement with the experimental results, it is verified that the experimental system has good applicability to blasting research.
  • Articles
    HUANG Shan, YAO Yuedong, WANG Li, MA Ruoyu, WANG Jinwei, GUO Qinglin
    Science & Technology Review. 2018, 36(13): 65-72.
    The tight formation has the characteristics of the extremely low permeability and the sensitivity of the permeability to the effective stress. The conventional constant shape factor model cannot accurately characterize the transient inter-porosity flow characteristics. In this paper, a new model is established by considering the effect of the stress sensitivity and the time-dependent fracture pressure boundary condition. The Pedrosa substitution and the perturbation method are applied to eliminate the nonlinearity of the model. The Laplace transformation method is used to obtain the analytical solution in the Laplace domain. Based on the Duhamel principle, the solution under the time-dependent fracture pressure boundary condition is obtained. The results obtained by the new model are compared with those obtained by the model of Hassanzadeh and the finite element analysis to validate the new model. Finally, the influences of the stresssensitivity and the decreasing velocity of the fracture pressure on the shape factor and the velocity of the inter-porosity flow are discussed. It is shown that the larger the stress sensitivity coefficient, the smaller the value of the shape factor and the smaller the velocity of interporosity flow will be. The fracture pressure depletion has a significant effect on the inter-porosity flow. The effects of the matrix stress sensitivity become more pronounced when the effects of the fracture pressure depletion are considered. Moreover, the shape factor and the velocity of inter-porosity flow are different in different stages as the fracture pressure depletion coefficient is not the same. The velocity of the inter-porosity flow will increase first to reach an equilibrium and then decrease when the decreasing rate of the fracture pressure is small, which is different from the results obtained under the constant fracture pressure boundary condition. The estimation of the velocity of the inter-porosity flow would be inaccurate if the effect of the fracture pressure depletion is not take into account. The new model provides a theoretical basis for the development of tight reservoirs and can be used in the study of the well test analysis and the numerical simulation of multi-fractured horizontal wells in a tight formation.
  • Articles
    GAO Feng, TAN Xue
    Science & Technology Review. 2018, 36(13): 73-81.
    Evolution model and risk analysis of urban haze disaster chain are carried out on the basis of disaster system theory and the complex network theory in this paper. Through the information gathering and analysis of the causes and harm of urban haze disaster, the disaster chain mechanism of urban haze is analyzed, as well as the types and characteristics of disaster chain, according to the characteristics of disaster-causing factors, hazard-formative environment and hazard-affected bodies. By building the urban haze disaster chain evolution network model, qualitative risk analysis is made based on the out-in degrees and number of nodes in its subnets, the shortest path and average path, and the number of branched chains. Finally, the key steps are found and the solutions on disconnecting chains are presented. The results of risk analysis show that in the urban haze disaster chain evolution system, the haze event closely relates to the other crisis events. Through several times of transition, the harm effect might spread to the entire network, and the key links are the decline in atmospheric visibility, the decline in air quality or air pollution, traffic jams or paralysis, traffic accidents, resulting in urban atmospheric acid rain, urban greening, economic losses and endanger human health.
  • Articles
    MA Tianbing, LIU Jian, DU Fei, CHEN Nannan
    Science & Technology Review. 2018, 36(13): 82-87.
    Of traditional vibration displacement measurement methods, the indirect measurement method has its large error and low accuracy while the direct measurement method can achieve accuracy with high cost and poor utility. So a vibration displacement measurement method using machine vision is proposed. A motor-driven flexible arm is selected as the measurement object. A CCD camera is used to collect the motion image of the marker on the arm's manipulator. After the visual processing such as threshold segmentation and centroid detection, the vibration displacement information of the manipulator is obtained. An experimental platform is built to verify the method. The result is compared with the vibration displacements obtained by piezoelectric material measurement method and the simulation method. It is shown that the machine vision-based vibration displacement measurement method can be well applied to the flexible arm without any contacts. The accurate and real-time vibration displacement measurement of the arm is superior to the piezoelectric material measurement method, avoiding the influence of formula errors and other effects, and has obvious advantages.
  • Articles
    ZHANG Xun, WANG Dongming, JIANG Dong, FU Jingying, LI Jiangtao
    Science & Technology Review. 2018, 36(13): 88-94.
    The purpose of this research is to meet the urgent needs of emergent biological hazard event simulation prediction research due to the new worldwide situation of complex biological hazard. With the help of the Cesium framework, an open source software tool for 3D geographic information technology from WebGL, this paper defines the overall framework of emergent biological hazard event platform. On this basis, a database of emergent biological hazard events is established, and for modules, namely analogue simulation function module, hazard assessment function module, auxiliary decision function module, and intervention measures function module are developed for three application scenarioes of bioterrorism, biological invasion, and infectious diseases. So a 3D earth biological platform for emergent biological hazard events has been implemented, which aims to provide a visual analysis platform for emergent biological hazard event research decision-making with data support and software platform guarantee.
  • Articles
    LUO Tongyuan, WU Chao
    Science & Technology Review. 2018, 36(12): 76-85.
    This paper analyzes the principle and the system of security informatics, for the construction of the safety information science, with 4 kinds of the security information. According to the security information, 6 kinds of scientific principles of safety informatics are identified:the security of human body information principle, the safety principle, the material information security environment, the principle of information security management information, the social security information principle and the principle of information security system principle, in 30 levels. The connotation of each principle is discussed. A honeycomb structure of the principles of safety informatics is constructed to reveal the relation and the development of the principles of safety information. It is shown that with the system safety and security as the background, a safe information under a new system of safety science principle can be built, enriched and improved.
  • Articles
    HU Guangwei, ZHANG Lian
    Science & Technology Review. 2018, 36(12): 86-93.
    The regional economy development is restricted by the supply of high-quality water resource. As an important source of drinking water and fresh water reserve for people's livelihood in the Dongting Lake Basin, the water quality of Dongting Lake directly affects people's health. To grasp the drinking water security situation in the Dongting Lake Basin, we take the advantage of monitoring data such as runoff, level and quality of Dongting Lake water both into and out of the lake, and use comparative analysis, mathematical statistics and water quality evaluation model, as well as other analytical methods to study the current situation of drinking water safety and the impact of the operation of the Three Gorges Project on drinking water safety in the Basin in terms of water quantity and quality. Aiming at the problems existing in drinking water safety, we discuss the reasons for the safety of drinking water in the Basin. We show that the surface water and groundwater in Dongting Lake are seriously polluted and that there are some problems such as excessive heavy metal and threat of drinking water for people and animals. Especially after the operation of the Three Gorges Project, the water into the lake of the Three Outlets of Jingjiang River drops sharply, and the total diversion of Three Outlets has decreased to 475×108m3/a, a reduction of 52%; continuous lowrainfall in the Basin also exacerbates the drought situation, with precipitation dropping by 52% over the same period of the previous year. Finally, we put forward countermeasures and measures to ensure the safety of drinking water in the Basin. First, allocation of water resources should be optimized and the protection of water resources should be strengthened so that the combination of water abstraction and pollution control can be strengthened. Then, the construction of drinking water projects should be increased in the Basin and the management of drinking water safety should be improved. Last but not the least, a basis for solving drinking water safety problem in the Basin is urgent, which may play an active role in ensuring the harmonious and stable development of the ecological economic zone of Dongting Lake.
  • Articles
    ZHANG Tian, TIAN Hanmin, RONG Xiaoying, ZHAO Kunyue, GUO Dan
    Science & Technology Review. 2018, 36(8): 65-70.
    As a kind of extremely wetting surface, the surface of superhydrophilic film has become one of the focuses of research in the field of the modern industry and the urban construction because of its self-cleaning, anti-fog and anti-corrosion properties. One method of defining extremely wetting surfaces is the measurement of contact angles, therefore, it is significant to obtain a high precision contact angle in the extremely wetting surface engineering. In this paper, several contact angle algorithms for improving contact angle accuracy for the ultra hydrophilic film surface are proposed, including the high volume method, the circle fitting method and the ellipse fitting method. In addition, it is shown that the accuracy of the calculation can be improved by the circular fitting algorithm when the contact angle is close to zero.
  • Articles
    ZHANG Yixin, MA Chunmeng, LIU Peng, FENG Limin, ZHANG Fengjun
    Science & Technology Review. 2018, 36(8): 71-78.
    The photocatalytic reaction with Bi2WO6 as a catalyst is found to be effective for removal of tetracycline in wastewater. In this paper, the treatment efficiency of Bi2WO6 photocatalyst for tetracycline wastewater is further improved through directly adding photosensitizer to the photocatalytic reaction. Bi2WO6 catalyst is prepared and characterized by XRD and SEM to explore its crystal structure and morphology. Meanwhile, the effects of five factors including anion, cation, photosensitizer dosage, initial concentration of tetracycline, and initial pH of tetracycline on the removal of tetracycline are studied. The results show that the photocatalyst is successfully prepared without any damage to the lattice structure, and that addition of sensitizer can improve adsorption and removal of tetracycline, and that the catalytic activity of Bi2WO6 is optimized. The promotion effects of anion Cl- and cationic Cu2+ are better than others, and after comparison the best photosensitizer is found to be copper sulfate. The removal rate of tetracycline can reach 88.79% when the addition of copper sulfate is 1.5 ml and the initial concentration of tetracycline is 70 mg/L. Besides, the adsorption efficiency is the best when pH is 5 or 8, the adsorption rates being 51.50% and 55.01%, respectively.
  • Articles
    CAO Ye, ZOU Zhendong, QIU Guoyu
    Science & Technology Review. 2018, 36(8): 79-86.
    Abstract (943) PDF (1131) HTML   Knowledge map   Save
    Life cycle assessment (LCA) method has been widely used in many fields since its birth, but the most prominent contribution is its application to environmental management. The technical framework of LCA can be divided into four parts:target and scope, list analysis, impact assessment (LCIA) and result interpretation. The methods of LCIA can be summed up as midpoint method and end point method. LCA has limitations in such as data acquisition, inventory allocation, boundary selection, evaluation models, temporal and spatial constraints, and uncertainty of results. In order to adapt to the requirements of environmental management and evaluation technology, LCA evaluation technology is being developed towards a systematic direction. LCA has so far expanded its application field and avoided its limitation in evaluation, which makes it become an indispensable tool for environmental management.
  • Articles
    YANG Xiaodan, ZHAO Luqiang, SONG Jianyang, Li Wanyu
    Science & Technology Review. 2018, 36(8): 87-92.
    Guided by the theories of the geographic information of the underlying surface and the distribution characteristics of forest, a forest fire weather forecast model is established through analysis of the relationship between meteorological factors (such as atmospheric precipitation, surface air temperature, humidity and wind speed) and the fuel status based on the ground observation data of 2425 stations in China and the T639 numerical forecast data. The predicted results indicate that the current model can well reflect the situations in the local areas of the forest with high probability for a correct prediction of fire weather, thus providing a good guidance for forest fire prognosis and prediction.
  • Articles
    CHEN Donglin, XIA Qi, DAI Siguang
    Science & Technology Review. 2018, 36(7): 74-79.
    Interest point is the key to improving the accuracy of e-commerce recommendation under big data environment. However, the existing predictive research ignores the comprehensive impact of various customers' behaviors and time series on interest points. In order to make up this gap, the article sets up a customer Web space and time super network model which involves four subnets:customer, time, behavior and interest point, and establishes the influence factors of behavior. Then, based on similarity of superlink prediction method and the establishment of connectivity matrix, the adjacency matrix is calculated and super triangle judgement is made, so that the most similar super edge and the best prediction results of interest points are obtained. Finally, experiment shows that the precision of interest prediction gets better with the decrease of time accuracy within the allowable range of time error. Compared with the traditional method of label prediction, the prediction accuracy is improved from 56.2% to 74%.
  • Articles
    ZAN Xiang, CHEN Chunliang, ZHANG Shixin, LIU Yan, WU Tonghan
    Science & Technology Review. 2018, 36(7): 80-87.
    Equipment maintenance task allocation and scheduling in wartime is an important part of equipment maintenance to meet the challenge of information warfare. To reflect the characteristics of equipment maintenance task allocation and scheduling, a systemic structure is established, including process dimension, logical dimension and knowledge dimension based on Hall three-dimension structure theory. Five important processes, five basic steps, and related technology and method are defined in the system structure. On this basis, task priority sorting, task allocation and task scheduling are confirmed as the key problems through the basic process of equipment maintenance task allocation and scheduling. And the target, restrain conditions, input conditions, output conditions and research focus are analyzed for each key problem.
  • Articles
    MA Ying, LIU Lu, AN Boxing, LI Fengyu, DING Dan, LIU Ruping, SONG Yanlin
    Science & Technology Review. 2018, 36(7): 88-94.
    Giant graphene oxide (GGO) with radial size distribution of 30~70 μm is fabricated using the modified Hummers method, and graphene oxide ink is prepared. Through direct ink writing, the optimal printing parameters and patterning of graphene oxide ink are realized. When graphene oxide with a concentration of 15 mg/mL is printed at 70 kPa and 3 mm/s, the printing line is smooth and its morphology is fine and controllable. When the printing line is reduced by 15% hydroiodic acid for 3 h, its reduction degree is the highest and has the best electrical performance, with a conductivity up to 4.40×104 S/m, which is much higher than that of the graphene patterned by the existing printing technology. Patterning of graphene oxide ink on various flexible and non-flexible substrates, such as PET, PDMS, glass and silicon wafers is alao successfully achieved. Reduced graphene oxide pattern can be used as a connecting conductor to realize the integration of LED, which is of great significance for the development of graphene based printed electronic devices.
  • Articles
    FANG Yifang, SONG Yanyan, DU Mengxin
    Science & Technology Review. 2018, 36(6): 90-96.
    The intelligent manufacturing involves a deep integration of the advanced manufacturing, the ICT and AI technology in the fields of end products and the manufacturing equipment, and the intelligentialization of manufacturing products are the core. The intelligent manufacturing also provides an important guarantee to achieve high-efficiency, high-quality, low-consumption and intelligent services. This paper reviews the latest studies of the intelligent manufacturing at home and abroad, proposes eight basic characteristics of the product intelligetialization, analyzes the related relationship between these characters and the intelligent manufacturing reference model, then validates the reasonableness of the characters of intelligent products based on the patents research.
  • Articles
    FENG Xiang, YANG Zhaokun, ZHANG Qiang, SU Yalong, QIAO Yun, LIU Sha, YANG Ruizhi, SUN Xiao, QIU Yun, WANG Dan
    Science & Technology Review. 2018, 36(6): 97-104.
    The slow development of the lithium ion battery material technology hampers the growth of the energy density of commercial lithium ion batteries. The form of smart devices develops in the direction of portability e.g. ultra-thin and ultra-light along with the arrival of the mobile internet era, which poses a great challenge to the battery capacity and the device stand-by time. This paper reviews the methods of improving the stand-by ability of smart devices, focusing on the technology of the lithium ion battery widely used in smart device and the technical status of the key elements in the lithium ion battery cell. The tendency of the device power consumption and the machine structure design of smartphones are analyzed, including the power consumption distribution and the technical upgrading of the hardware in the smartphone field. The display module is shown to consume most power of a smart device. The logic power consumption and the BLU power consumption could be reduced effectively by using the pixel rendering technology. With the integration in the PCB and the processability of the PCB layout developments of the hardware elements, a larger space in the device will be used for a larger volume battery. The battery life will be prolonged with the multiple coordination and optimization of hardware elements of the smart devices.
  • Articles
    CHEN Liang, WANG Jingjing, ZHOU Zhihua, LI Qiaoru, CHEN Mingming
    Science & Technology Review. 2018, 36(6): 105-111.
    Some important intersection nodes in the urban road network are generally defined by a single indicator such as the traffic flow or the number of connected links. It is difficult to ensure the reliability of the road network once the traffic incident in the hub node happens. In this paper, according to the free scale features, the urban road network is simplified as a weighted complex network, in which the traffic impedance is taken as the weight parameter, and a method of the weighted network node importance transmission contribution matrix is proposed. The method comprehensively combines the intersection location in the road network, the number of connected links, and the traffic impedance of associated links, to evaluate the intersection node importance. The node efficiency value is used to represent the information related with the intersection location, meanwhile, the node degree value and the traffic impedance value are fused to characterize the importance dependencies of adjacent intersections in the process of the traffic information transmission. A regional road network in Tianjin is used as a test sample to validate the proposed approach. The cascading failure is simulated on the network by continuously removing important nodes. Simulation results show that the largest subgraph size based on the proposed method falls by 9.10%, as compared with the weighted node contraction method when the top 8 important nodes are continuously removed. These results provide a theoretical basis for the congestion warning for the urban traffic network.
  • Articles
    LONG Xiaoyong, CEN Guoping, CAI Wantong, ZHANG Jianjun, ZHANG Yongxiang, WEN Xiaoping, YANG Jiale
    Science & Technology Review. 2018, 36(6): 112-118.
    In order to see the influence of the compaction degree and the moisture on the frost heaving properties of the gravel soil in the seasonally frozen region of Qinghai-Tibetan Plateau, and provide a foundation for the prevention and the control of the soil frost heaving, a series of frost-heaving ratio indoor tests with improved test devices are conducted to study the influence of the compaction degree, the initial moisture content and the water replenishing on the frost-heaving ratio. It is shown that, the frost-heaving ratio of the gravel soil decreases after the first increase with the increase of the compaction degree, with its maximum at the compaction degree of 95% under the closed condition and with the same initial moisture content, and it increases linearly with the increase of the initial moisture content under the closed condition and with the same compaction degree. There are highly related functional relationship between the compaction degree, the initial moisture content and the frost-heaving ratio, which can be used to forecast related indicators in some cases. The frost-heaving ratio increases over several times under the open condition than under the closed condition. It is necessary to reduce the underground water level, to set the water-resisting layer, and to strictly control the compaction degree and the initial moisture content for the effective prevention and control of the soil frost.
  • Articles
    SHEN Sichu, CHEN Xi, GUO Huifang, LI Shu
    Science & Technology Review. 2018, 36(5): 77-84.
    Human being, as the wisest of all creatures, has been challenged by artificial intelligence. In order to tackle the challenge, we need to identify and enhance the unique capacity of human being as the wisest of all creatures. According to Yuval Noah Harari's viewpoint presented in Sapiens:A Brief History of Humankind, the capacity to believe in things purely existing in the fiction is the key to moving up in the food chain. Two decision scenarios are therefore developed to explore whether the two elements of fiction ("fiction reading comprehension" and "future coming true") can serve as a behavioral marker to distinguish qualified from unqualified homo sapiens. The result reveals significant differences in terms of responses to the scenarios between the criterion populations of unqualified homo sapiens, such as lawbreakers and drug addicts, and qualified homo sapiens (normal control). The findings support the notion that capacity of fiction can serve as a candidate behavioral marker for distinguishing qualified from unqualified homo sapiens. Furthermore, the findings provide pilot evidence for the viewpoint that the cognitive capacity of fiction is the unique capacity of homo sapiens.
  • Articles
    JIANG Fang, FU Liping, WANG Yongmei
    Science & Technology Review. 2018, 36(5): 85-91.
    The peak electron density of the 135.6 nm nightglow radiation data by COSMIC tiny ionospheric photometer measurement is retrieved. The peak electron density values from the tiny ionospheric photometer and the ionosonde observation are compared. The results show that the 135.6 nm nightglow radiative intensity values must be revised to suppress the influences of the 130.4 nm band and the near ultraviolet upto visible wavelength radiation. The retrieval results from the revised data have good consistency.
  • Articles
    ZHANG Huaiwen, CHENG Yuanfang, ZHU Haitao, SHI Jihui, HAN Xiuting
    Science & Technology Review. 2018, 36(5): 92-97.
    In order to understand the acoustic characteristics and differences of muddy siltstone hydrate sediment (MSHS) and siltstone hydrate sediment (SHS) in the shallow seabed of South China Sea, a simulation experiment is conducted to investigate the acoustic response characteristics of these two hydrate sediments with the ultrasonic detection technology. The results show that the acoustic velocities of these two hydrate sediments will increase with the increase of effective confining pressure. However, when the effective confining pressure increases to the effective confining pressure saturation point, the acoustic velocities of these two hydrate sediments will not change anymore. Meanwhile, with the increase of hydrate saturation, the effective confining pressure saturation points of these two hydrate sediments will also increase. The effective confining pressure saturation point of MSHS is higher than that of SHS and the difference is between 7-10 MPa. Under the same effective confining pressure, the larger the hydrate saturation, the faster the acoustic velocity for both hydrate sediments, showing a "slow-fast-slow" tendency. The 20%-40% of hydrate saturation is the fast increasing range of the acoustic velocity, with an increase over 22%. The acoustic velocity of MSHS is greater than that of SHS under the same experiment condition. Furthermore, the change of hydrate saturation and effective confining pressure have a great effect on the acoustic velocity of these two hydrate sediments, and acoustic velocity has a greater influence on MSHS than on SHS.
  • Articles
    WU Yiwan, ZHU Yue, LI Fan
    Science & Technology Review. 2018, 36(5): 98-104.
    This paper focuses on the lane keeping assistance system (LKAS) for a four in-wheel motor drive electric vehicle. A new method for lane keeping assistance is presented, which applies additional yaw moment to the electric vehicle to achieve lane maintenance with active distribution of four wheels driving/braking torque. The lane keeping assistance system is divided into three layers. In the upper layer, assistance control decision is made, and the desired yaw rate is calculated by considering vehicle-lane deviation, vehicle dynamic and limitation of road adhesion. In the middle layer, a sliding mode controller (SMC) is designed to control the additional yaw moment. In the lower layer, yaw moment is produced by distributing of drive/brake torques between the four wheels. Lane keeping assistance is carried out by tracking desired yaw response. The LKAS is evaluated via Carsim/Simulink. The simulation result for a single lane change test shows that the proposed method can make the vehicle have good dynamic stability, and can restrict the vehicle within the lane and avoid lane departure accidents.
  • Articles
    KONG Qingxian, XIN Zhongbao, XIA Xiaoping
    Science & Technology Review. 2017, 35(24): 57-65.
    The plant diversity is one of the important ecological factors in the riparian, as an important symbol of the riparian healthy. In order to ensure the riparian health in Beijing mountainous area and reveal its influencing factors, sampling and indoor analysis are carried out, to study the relationship between the plant diversity and the environmental factors. According to the principle component analysis and the cluster analysis, the Huaijiu river riparian falls into six types, namely, the natural riparian, the near-natural riparian, the artificial bank plant riparian, the artificial bank ornamental plant riparian, the artificial bank sparse plant dry-stone riparian, and the artificial bank masonry riparian. With the increase of the elevation, the diversity index of the riparian increases. Different riparian types have different variations of plant species, and the diversity index of the artificial bank masonry riparian is significantly lower than other riparian types (n=50, P<0.05). The riparian tree and shrub Shannon diversity and Margalef abundance index are significantly lower than those of the herb (n=50, P<0.05), and the herbaceous plants may adapt to the environment easily and with flexibility that makes various and abundant plant species, while the trees and shrubs are vulnerable to the human influences and have lower diversity and abundance. The Pearson correlation analysis shows that the riparian plant Shannon diversity index and the hardening area ratio and the slope types have significantly negative correlation(n=50, P<0.01), while the altitude is significantly positively related to the riparian plant Shannon diversity index and the hardening area ratio(n=50, P<0.05). This study can provide a reference for the riparian health and the protection of the plant diversity, and provide a theoretical support for the development and management of the riparian.
  • Articles
    FANG Fang, BU Fanpeng, TIAN Shiming, QI Linhai, LI Xiawei
    Science & Technology Review. 2017, 35(24): 66-70.
    This paper introduces the methods and the steps of predicting the power load by the BP neural network with cluster optimization in batch processing time series. Through the preconditioning of historical data, the setting of the initial clustering center and the determination of the optimal number of clusters, a clustering prediction model of the load curve is established based on the clustering results of the historical data and the relevant parameters such as the temperature, the humidity, the air pressure, the wind speed and the time (the current week). The results show that with the clustering algorithm, the related factors and the BP network adaptive rate can be comprehensively considered, while the training speed is improved, to obtain more accurate prediction results.
  • Articles
    LI Shuai, LI Xiangrong, WANG Guohui, SONG Linfeng
    Science & Technology Review. 2017, 35(24): 71-75.
    For enhancing the explosion resisting performance of the outer structure, the dynamic response of plates with different stiffeners under the explosion loading is numerically simulated. The plates are with their four sides fixed. Finite element models for four kinds of plates are built using the ABAQUS software, to simulate the dynamic response. The energy distribution, the maximum deflection at the plate center and the stress distribution are analyzed and compared. To resist the explosion loading, the increased number of stiffeners does not mean a better performance. Among the four plates with different stiffeners, the triangle stiffener coupled plates are the best one for the anti-explosion performance.
  • Articles
    LIU Jiexi, ZHU Yuxia, QIU Jinjia, LI Yue, ZHONG Haizheng
    Science & Technology Review. 2017, 35(24): 76-81.
    The method for the methanol and the carbon dioxide to directly react to prepare the dimethyl carbonate suffers from several deficiencies, such as too strict operation conditions, complex processing equipments, and low conversion rate of the methanol. A carbonabsorption solution is developed in this paper, in which the saturation concentration of the carbon dioxide reaches 0.528g/ml; the electrolysis is used to activate the carbon dioxide and in the electrolytic process the carbon dioxide is continuously added until saturation so as to obtain the electrochemical activation solution; the methyl iodide is used as the inducer, which is refluxed for 120 minutes with the methyl alcohol at 60℃, so as to obtain the dimethyl carbonate, with a purity of 99.0%, and the conversion rate of 99.5% (measured based on the amount of the methanol).
  • Articles
    CHEN Ying, HE Junhui, TIAN Hua, WANG Donghui, YANG Qiaowen
    Science & Technology Review. 2017, 35(23): 46-51.
    A series of copper manganese oxides are synthesized using a simple redox method by controlling the molar ratio of Cu and Mn and calcination temperature. The optimum conditions are determined by investigating the effects of synthesis conditions on crystal phase, morphology and catalytic activity of catalysts. The relationship between structure and activity of catalyst is revealed by combining X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and other characterizations. The results show that more oxygen vacancy generated by the addition of copper may promote the oxygen species mobile, which leads to a lower reduction temperature and strong ability of oxidation reduction. The amorphous type of copper manganese oxide with poor crystallinity is also beneficial to the increase of oxygen vacancy, which facilitates the catalytic oxidation of formaldehyde. The catalyst with copper and manganese molar ratio of 1:2 and calcination temperature of 300℃ exhibites the best catalytic performance and can completely decompose formaldehyde at 90℃.
  • Articles
    LU Xiaoguang, ZHANG Han, ZHAO Xiaohong, XIE Qing, MAO Yun, TANG Jintian, LI Liya
    Science & Technology Review. 2017, 35(23): 52-57.
    To investigate the effects of magnetic-mediated hyperthermia(MMH) in combination with Aidi injection on human lymphoma Daudi cells in vitro, the biocompatibility and temperature rising behavior of selected magnetic media are studied. Then cell proliferation in culture is studied in human lymphoma Daudi cell lines exposed to MMH and Aidi separately and in combination. The cell apoptosis and cycle of Daudi cells are analyzed by flow cytometry. Theoretical calculations indicate that the biocompatibility of MMH magnetic media is satisffactory. In vivo experiments it also generates heat effectively. The survival rate of Daudi cells exposed to MMH (300 kHz, 40 Gs, 30 min) is (78.48±0.95)%, but significantly decreases to (9.25±2.05)% (P<0.01) when being exposed to the combination of MMH and Aidi. MMH in combination with Aidi can promote Daudi cells apoptosis, but the change in cell cycle is not obvious. The MMH magnetic media is feasible to Daudi cells in vitro. MMH alone could induce apoptosis of Daudi cells and significantly enhance anti-tumor effect with Aidi injection.
  • Articles
    XU Linlin, ZHU Xiaotong, ZHANG Jinpeng
    Science & Technology Review. 2017, 35(23): 58-61.
    The title compound spiro[indoline-3,3'-pyrrolizin]-2-one C27H24ClN3O2 is synthesized by the one-pot multicomponent reaction of chalcone, 5-methylisatin and proline in trace amounts of methanol under stirring at 60℃. Its structure is determined by single crystal X-ray diffraction. The crystal is monoclinic, space group P2(1)/c, with Mr=504.01, a=0.84907(6) nm, b=1.07072(9) nm, c=2.9121(4) nm, V=2.6415 (5) nm3, Z=4, Dc=1.267 mg/m3, μ=0.180 mm-1, and F(000)=1064. The structure is solved by direct methods and refined by full-matrix least squares method to the final R=0.0657 and ωR=0.1376. X-ray analysis reveals that the newly formed ring of tetrahydropyrrole in the crystal structure is of envelope conformation.
  • Articles
    YE Xiaorong, SHAO Qing, XIAO Rong
    Science & Technology Review. 2017, 35(23): 62-69.
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    In order to take the advantages of new technologies such as blockchain, smart contract and Internet of Things, and improve the informatization level of supply chain, a supply chain prototype system, which is based on blockchain, smart contract and Internet of Things, is developed. With the help of two-dimensional code, RFID and NFC in the Internet of Things, automatic uploading of the supply chain data is implemented. The system uses blockchain and smart contract to completely save the data of the whole supply chain, thus it ensures the data is transparent, traceable and cannot be tampered with. Meanwhile it takes protection of privacy data into account and provides data query functions at different levels for users. Through these improvements, the supply chain system is more automated, safer and more reliable, and makes traceability easy.