Most Download

  • Published in last 1 year
  • In last 2 years
  • In last 3 years
  • All

Please wait a minute...
  • Select all
  • Science & Technology Review. 2015, 33(1): 122-122.
    Abstract (610) PDF (70035) HTML   Knowledge map   Save
    2015 年,世界上最早的科学出版机构英国皇家学会,将庆祝最早的同行评议期刊——Philosophical Transactions出版350 周年.
  • Exclusive
    SHI Siqi, XU Jiwei, CUI Yanhua, LU Xiaogang, OUYANG Chuying, ZHANG Yanshu, ZHANG Wenqing
    Science & Technology Review. 2015, 33(10): 20-30.
    Abstract (1727) PDF (46629) HTML   Knowledge map   Save
    Multiscale models and simulations play a significant role in the "Materials Genome Initiative". This article reviews computational methods at spatial scale from quantum to microscopy, mesoscopy, and macroscopy, and at temporal scale from picosecond to nanosecond, and microsecond. The corresponding techniques ranging from first- principles calculation to molecular dynamics, macroscopic thermodynamics/kinetics models and simulations, and finite element methods are introduced.
  • Foreword
    Science & Technology Review. 2015, 33(5): 1-1.
    Abstract (994) PDF (42276) HTML   Knowledge map   Save
    在2014 年6 月的两院院士大会上,习近平主席讲到:“我国经济规模很大但依然大而不强,我国经济增速很快但依然快而不优。”“……从总体上看,我国科技创新基础还不牢,自主创新特别是原创力还不强,关键领域核心技术受制于人的格局没有从根本上改变。”我们“不能总是指望依赖他人的科技成果来提高自己的科技水平,更不能做其他国家的技术附庸,永远跟在别人的后面亦步亦趋。”这些讲话为科技工作者敲响了警钟。同样,中国离桥梁强国也有不小差距,尤其在质量和耐久性、创新设计理念、高性能材料应用以及工业化施工等方面仍有许多不足。
  • Articles
    LI Benxian;LI Mengjun;SUN Duoyong
    Abstract (756) PDF (41377) HTML   Knowledge map   Save
    A dynamic society network analysis method is adapted to study terrorism organization structure and its invulnerability. Firstly, a selective attack method is proposed to destroy terrorism organization network. Secondly, the mesosphere is attacked, and then other segments are attacked according to the degree-distribution centralities of network. The minimal-cut set of graph theory is applied to scout the terrorism network of invulnerability and attack its augmentable chain. The experimental results show that these methods precede traditional attacking methods. It is easy to destroy the entire terrorism organization network.
  • Articles
    CHEN Pengye;CHEN Jun;ZOU Xianfeng;HOU Jun;LIANG Haijun;LI Na
    Abstract (631) PDF (31007) HTML   Knowledge map   Save
    Qi Chengwei's formulae consists of the two formulae for predicting horizontal well productivity, proposing at first time in the world; the formulae is only for the prediction of ribbon-shaped petroleum reservoir, but not for the prediction of natural gas reservoir. In order to predict the productivity of branched horizontal well in ribbon-shaped gas reservoir in the Sichuan-Chongqing region, according to the similarity principle between gas seepage and liquid seepage and the relationship between gas relative permeability and sulfur saturation summed up by Roberts, the famous Qi Chengwei's formulae are successfully generalized to pseudo three-dimensional productivity formulae of horizontal well in ribbon-shaped sour gas reservoir. On the basis of the revised formulae, the impact of sulfur deposition amount and permeability anisotropy coefficient on productivity is analyzed, and important knowledge that the effect of sulfur deposition amount on productivity is greater than that of permeability anisotropy coefficient is obtained and longitudinal bilateral horizontal well possesses more advantages than transverse horizontal well in ribbon-shaped sulphuric gas reservoir. At last, a proposal that the pseudo three-dimensional productivity formula derived by Qi Chengwei for radial branched horizontal well in circular petroleum reservoir should be promoted to sulphuric gas reservoir is put forward.
  • Exclusive
    WANG Haizhou, WANG Hong, DING Hong, XIANG Xiaodong, XIANG Yong, ZHANG Xiaokun
    Science & Technology Review. 2015, 33(10): 31-49.
    Abstract (8220) PDF (30409) HTML   Knowledge map   Save
    Over the last 40 years, high throughput experimentation has been demonstrated to be an effective approach to generate huge amount of material data in a short period of time, and it is now considered a key element of Materials Genome Initiative (MGI) to fulfill its promise to deliver materials of emerging importance with much faster paces and lower costs. In this article, the briefly history for high throughput materials synthesis and characterization is recalled. A series of representative techniques are reviewed, their limitations are identified, and the challenges and future trends are analyzed. In perspective, a facility consisting of in-situ real time materials processing, characterization and analysis based on synchrotron light sources or spallation neutron sources, as well as the original position statistic reflecting mapping technology for non-uniform materials are likely to play important role in the future generation high throughput material experimentation.
  • 科技事件
    . 2012, 30(27): 9-9.
    Abstract (365) PDF (27565) HTML   Knowledge map   Save
  • Exclusive
    WANG Hong, XIANG Yong, XIANG Xiaodong, CHEN Liquan
    Science & Technology Review. 2015, 33(10): 13-19.
    Abstract (3883) PDF (27086) HTML   Knowledge map   Save
    Materials research and development today still depends primarily on scientific intuitions, experiences, as well as trial-anderror experiments. This process is time-consuming and costly, and has increasingly become the bottleneck for technological and social advancement. In June 2011, President Obama of the United State announced Materials Genome Initiative (MGI) as part of Advanced Manufacturing Partnership, aiming to accelerate process from materials discovery, development, manufacturing, and deployment process and cut the cost at the same time by integrating computational materials design, high-throughput experimentation, and data management. China began to show great interest in more efficient materials research and development as early as June 1999 by organizing the 118th Xiangshan Science Forum on Integrated Combinatorial Approaches for Materials Discovery and Optimization. In December 2011, The S14 Xiangshan Science Forum on System Engineering in Materials Science was jointly sponsored by Chinese Academy of Sciences (CAS) and Chinese Academy of Engineering (CAE), in response to the MGI. In addition, a series of conferences and forums were held across the nation from 2012 to 2014, to discuss MGI and China's strategy. A consensus has been reached among Chinese materials community including universities, industry, and research institutions. Both CAS and CAE submitted Strategic Consultation Report on Materials Genome to the State Council of China in 2014, respectively, proposing to launch China's Materials Genome Program as soon as possible. In this article, we introduce the basic concepts of MGI, review the global progress and trends, and make recommendations on the national policy, strategy and technological pathways of China's Materials Genome Program.
  • WANG Hongzhi
    Science & Technology Review. 2014, 32(34): 78-84.
    Abstract (1632) PDF (26892) HTML   Knowledge map   Save
    Big data have wide applications. Since the quality of big data plays a crucial role in these data-centric applications, data quality management techniques for big data are in demand. Although some theories and techniques for data quality management have been proposed, due to the volume, variety and velocity of big data, current methods could hardly be applied to data management for big data. This paper discusses the problems and challenges for error detection, error repair and query processing of dirty data in big data management, and identifies intractability, mixed errors and the lack of knowledge as three new challenges to data quality management. The progress of big data quality management in these three aspects is reviewed and open problems for future research are proposed.
  • Reviews
    . 2009, 27(0916): 110-115.
    Abstract (1780) PDF (26662) HTML   Knowledge map   Save
    The terms "nucleators", "nucleator compound(s)", "nucleating agent", "nucleating agents" generally mean any additive to polymer, individually or in a combination, that produces nucleation sites for polymer crystals in the transition from its molten state to a solid, cooled structure. Any compound that exhibits such a beneficial effect and property is included within this definition. Such nucleator compounds more specially include dibenzylidene sorbitol types, substituted aromatic phosphate, dehydroabietate-based nucleators and the like. Aromatic carboxylic acids and their metal salts, such as sodium benzoate, are an important type of nucleators. This paper reviews the research and application of sodium benzoate as nucleating agent of thermoplastic materials. Sodium benzoate is made by the neutralization reaction of benzoic acid with sodium bicarbonate solution, and as a dispersion type nucleating agent, it can increase the crystallization temperature of polypropylene(PP) and shorten the crystallization time of PP, and also can change the crystalline form of PP under high-pressure crystallization. When sodium benzoate is used in PET and PEN as a nucleating agent, it plays its role by reacting with polyester(e.g. PET or PEN). It is shown that the improving routes of sodium benzoate nucleating agent are as follows: increasing its purity, reducing its particle size and combining actions with other nucleating agents.
  • Exclusive
    XIANG Xiaodong, WANG Hong, XIANG Yong, YAN Zongkai
    Science & Technology Review. 2015, 33(10): 64-78.
    Abstract (1637) PDF (26088) HTML   Knowledge map   Save
    Combinatorial material chip technology is a key element of the high-throughput materials experimentation which enables fulfillment of the Materials Genome Initiative. A typical combinatorial materials library contains 10 to 108 samples on a single substrate, and their compositions, structures, and properties are rapidly characterized. Over the past two decades, much progress has been made in combinatorial materials synthesis and characterization techniques. Combinatorial materials screening has been widely applied in almost all fields of materials research. In this article, examples were chosen from 15 categories of materials, such as electronic materials, magnetic materials, photonic materials, optical materials, energy materials, dielectric materials, catalysts, and alloys, to demonstrate the effectiveness and efficiency of the combinatorial methodology in new materials discovery, materials and devices optimization, as well as fundamental physics research.
  • 探索
    . 2002, 20(0204): 3-6.
    Abstract (566) PDF (23953) HTML   Knowledge map   Save
    北京大学闫学杉副教授于1999年在《科技导报》第八期上发表一篇文章---《关于21世纪信息科学发展的一些见解》(以下简称闫文) ,在国内信息科学界引起强烈反响。我们在编印《信息哲学、一般信息论及生命信息学论文汇编》第一集时 ,全文转载了闫文。该文对促进我们关于生命信息学及信息科学基础的研究起了重要作用。湖北大学在数学与计算机科学学院生命信息学科组的基础上 ,于近期又成立了信息科学研究中心 ,我们提出了关于信息科学基础研究的基本框架 ,包括8个方向及28个相关选题(见本文附录) ,作为中心的研究方向。本文将对构成选题框架的基本思想给出一个简要的说明 ,提出一些初步认识 ,作为深入研讨的引论。
  • News Focus
    Science & Technology Review. 2015, 33(9): 9-9.
    Abstract (1017) PDF (23467) HTML   Knowledge map   Save
    4月18日, 国内生物学杂志《蛋白质与细胞》(Protein & Cell)在线发表了中山大学生命科学学院副教授黄军就团队的研究成果: 他们利用基因编辑技术, 试图修改人类胚胎中可能导致β型地中海贫血的基因, 这是世界首次发表编辑人类胚胎基因组的研究成果。论文发表后迅速在国内外科学界掀起波澜, 该研究获得国内同行认可, 却引起国外科学家以及伦理学家的抗议。国内伦理学家认为, 这种反差恰恰暴露出我国在科研领域的伦理意识、伦理规范和相关法律的薄弱地带, 国家应该暂停相关研究, 并尽快讨论、建立伦理规范, 出台相应的法律法规。
  • 科研管理
    . 1998, 16(9805): 14-17.
    Abstract (584) PDF (23126) HTML   Knowledge map   Save
    引言本世纪50年代以来, 随着全球经济的飞速发展和科技的不断进步, 各国都在努力提高自身的综合实力, 以期在全球性的竞争中具备更强的生存能力。在这一过程中, 以能源工程、建筑工程、空间工程为代表的大型项目建设, 反映了一个国家和地区的综合实力, 因而其成败都有巨大的影响力。项目尤其是大型项目的技术复杂程度日益增高, 而投资者在质量、工期、投资效益等方面的要求也越来越高, 这就使得项目的组织管理成为决定项目成败的关键。因而, 各国都投入了大量的人力、物力从事项目管理方法的研究, 并取得了大量的成果。
  • Articles
    XI Cheng, SHI Zejin, WANG Changcheng, LI Yi
    Science & Technology Review. 2015, 33(11): 29-33.
    Abstract (542) PDF (22780) HTML   Knowledge map   Save
    According to the characteristics of the lateral heterogeneity geological changes of channel sand body, this article uses the pure seismic information, in which low frequency information is well preserved, to predict the sand body and fluid by extracting pure seismic amplitude information by doing relative impedance inversion and using the low-frequency incremental attribute. According to the prediction results of sand body and fluid, well location optimization can be performed. Five wells were suggested and four of them had high yields. The research result can be used as a basis for the next step of the production of the oil field well deployment, and it also can be popularized in similar geological conditions blocks.
  • Articles
    . 2010, 28(17): 54-57.
    Abstract (828) PDF (22496) HTML   Knowledge map   Save
    The preparation of CoFe2O4 ferrofluids by Massart's method is discussed in this paper. The structure and the shape of CoFe2O4 nanoparticles are characterized by X-ray diffraction and transmission electron microscopy, respectively, and the results show that the particles' size follows a logarithmic normal distribution, with the average diameter of 12.76nm and the crystal particle's average diameter is 11.15nm. The magnetization curve of CoFe2O4 particles is determined at room temperature by VSM, with the saturation magnetization of CoFe2O4 particles of 217.50kA/m. The magnetization curves of ferrofluids with volume fractions of 1%, 1.2% and 1.5% are determined at room temperature by VSM. It is found that the saturation magnetization of ferrofluids is significantly less than particle's saturation magnetization fVMps, because of bulk aggregations, chain-like aggregations and ring-like aggregations in ferrofluids at the same time. The bulk aggregations and the ring-like aggregations reduce the saturation magnetization of ferrorluids. The saturation magnetization of ferrofluids after frozen is greater than that before frozen, as the ring-like aggregations are broken by H2O molecule's interaction during the frozen process, which increases the parameter γ and the saturation magnetization of ferrofluids after frozen.
  • Articles
    ZHAN Jianchao;YUAN Xiaomei;MA Xiaoxiao;LIU Zhijian
    Abstract (591) PDF (21934) HTML   Knowledge map   Save
    The suitable guidance law of air-to-air in Endgame must ensure that the missile with the minimum miss-distance hits the target implementing best escape strategy. Because the characteristic of maneuverable target is hard to be mastered, and in order to improve the hit accuracy of missile, it required the higher motor overload and the smaller time constant of missile flight control system in practical design of engineering. Thus introduce of reaction-jet control can obviously improve the missile maximum available overload, and reduce the time constant of missile flight control system. In this paper a variable structure guidance law is designed based on the proportional guidance law. Variable structure control system can provide the same features to overcome the influence of target maneuver, and achieve the goal of zero under the bounded maneuvering condition of LOS angular velocity, which made the ballistic flight to show the characteristics of parallel approaching method in the missile-after guidance process, and then it can improve the missile guidance performance. Analysis of the guidance loop on the stability and simulation analysis of the guidance system with or without the reaction-jet controller demonstrated that the miss-distance of the variable structure guidance law is smaller than PNG and the effect is better with reaction-jet controller.
  • 资源环境
    . 2001, 19(011): 54-56.
    Abstract (516) PDF (21724) HTML   Knowledge map   Save
  • Forum
    Science & Technology Review. 2015, 33(9): 12-12.
    Abstract (1445) PDF (21548) HTML   Knowledge map   Save
    中山大学黄军就等人利用CRISPR/Cas9 系统对人类胚胎中导致β型地中海贫血症基因进行修改注射, 这是人类首次对自身胚胎进行突破性编辑尝试。相关论文被NatueScience 退稿, 最终发表在我国主办的Protein&Cell 上。令人意想不到的是, 这篇论文在全球范围内引发巨大伦理争议。不少国内生物学家对此给予了强力声援, 但此项研究也遭到不少国外同行的强烈指责, 呼吁要在全球范围内尤其是那些监管不严的国家和地区暂时禁止编辑人类胚胎基因研究。那么, 到底该不该编辑人类胚胎基因呢?又该如何审查和监管这项颇具伦理争议的新颖技术之临床应用呢?
  • journal1. 2014, 32(22): 1-1.
    Abstract (283) PDF (21483) HTML   Knowledge map   Save
    京津城际铁路是中国第1条世界一流的高速铁路,该工程长120 km复线,从施工、调试到运营仅用了1年半时间,是对中国高速铁路各种创新成果进行试验应用的检验,是示范性工程,也是今后进行其他成果试验、研究创新的基地。
  • 农业
    . 2000, 18(0002): 3-6.
    Abstract (385) PDF (21409) HTML   Knowledge map   Save
    从我国目前的情况看, 粮食政策设计(本文所指的粮食政策是粮食流通政策, 以下同)最重要的目标应该是保护农民的利益, 确保粮食供给和物价的稳定, 换句话讲, 只有达到了上述目标的粮食政策才能算是比较合理的。
  • 艾滋病研究专题
    . 2005, 23(0507): 29-33.
    Abstract (1550) PDF (20747) HTML   Knowledge map   Save
    Although the HAART(Highly Active Antiretrovirus Therapy) can not completely cure HIV/AIDS, it makes the fatal disease into the chronic and controllable disease with reducing mortality and morbility throughout the world. TCM has been used in the research of HIV/AIDS and treating HIV/AIDS for many years.Many Chinese herbs have some effect on inhibiting HIV thought the basic research. TCM can enhance immune function, improve symptoms-signs, not reduce viral loading according with the Clinic research. In a word, TCM have some advantages, such as improving the clinical symptoms, enhancing immune function,good adherence,low cost and so on.
  • Science & Technology Review. 2014, 32(34): 86-86.
    Abstract (343) PDF (20696) HTML   Knowledge map   Save
  • Reviews
    WANG Yu;WEI Chao;ZHANG Song
    Abstract (634) PDF (20490) HTML   Knowledge map   Save
    The sensitivity and anti-interference ability of pyrotechnics is important to ammunition safety. Therefore, improving insensitive pyrotechnics is the key point for the insensitive weapon research. Most advanced techniques, such as light, electricity, and magnetism are taking place of fire and heat in pyrotechnics, making pyrotechnics much more safety. The advances in the areas of new techniques and new energetic materials for insensitive pyrotechnics are discussed. New techniques, such as laser ignition, explosive logic circuit, and slapper detonator, are reviewed. The structure, principle, history, and latest achievements are introduced. The research level between China and developed countries is compared with each other; the developing trend of these techniques is talked about. In addition, new energetic materials invented by developed countries, such as LLM-105, DAAzF, FOX-7, TNAZ are summarized, and their developing status is introduced. By comparing the differences between China and developed countries, the shortcoming of China is pointed out, particularly some deficiencies in insensitive pyrotechnics. Some suggestions about the development strategy of insensitive pyrotechnics are given. Insensitive pyrotechnics is the key point of weapon safety, since the battle field survivability of soldiers and battle platforms become the factor of victory or defeat. It is also important to efficiently translate them into the productivity and fighting capacity by following the latest scientific research, working hard on self-determination innovation, and planning new product applications.
  • QIAO Jinjuan, LUO Jun, WEI Hongping
    Science & Technology Review. 2015, 33(1): 100-106.
    Abstract (889) PDF (20226) HTML   Knowledge map   Save
    Ebola virus disease (EVD) caused by Ebola viruses (EBOV) is an acute hemorrhagic infectious disease. Because of its high infectivity and high mortality rate(up to 90%), EBOV is listed as one of the most dangerous viruses to human by World Health Organization. Although US FDA gave it emergency clearance to use an experimental drug TKM-Ebola, there is no Ebola vaccine available yet. Rapid, accurate, simple and reliable laboratory diagnostic tests are required in suspected cases for timely treatment, epidemiological investigation and controlling the spread of the EVD. This review summarizes the principles, applications and progress of the laboratory diagnosis of EVD, covering virus isolation by cell culture, electron microscopy, reverse transcriptase polymerase chain reaction (RT-PCR) assay, antigen detection, antibody-capture enzyme-linked immunosorbent assay and serum neutralization test.
  • Reviews
    ZHAO Xiuliang, JIN Xiaofeng, CHENG Xiaolong, ZHOU Jianliang, LEI Long, CAO Zhou
    Abstract (806) PDF (20120) HTML   Knowledge map   Save
    This paper introduces the concept of blood born concentration measurement in the process of boron neutron capture therapy (BNCT). The deficiency of the physical, chemical, and nuclear methods for blood boron measurement is analyzed with a focus on the nuclear method. Rapidly and accurately measuring the blood boron concentration is the key in the process of BNCT. The status quo and development of the prompt gamma neutron activation analysis (PGNAA) are discussed. The problems and solutions of existing nuclear measurement methods are summarized. Future techniques for measuring blood boron concentration may be oriented toward fourdimensional estimation of exposure dose in the process of tumor therapy using BNCT.
  • Scientific Community Promotion
    Science & Technology Review. 2015, 33(13): 106-106.
    Abstract (916) PDF (19967) HTML   Knowledge map   Save
    本期科学共同体推介将继续为读者介绍,2015 年英国皇家学会夏季科学展22 项展览中的最后5 个展览项目,更多的展览内容介绍可以参考英国皇家学会官方网站
  • 高技术
    . 2001, 19(0103): 43-47.
    Abstract (1129) PDF (19675) HTML   Knowledge map   Save
    随着微电子技术的发展,特别是近年来以微型机电系统(MEMS)和微型光机电系统(MOEMS)为代表的微米纳米技术的发展,使得微型卫星、纳型卫星甚至皮型卫星的实现成为可能。 80年代以来,Draper实验室(美)、JPL(美)、LIT-TON公司(美)、LITEF公司(德)、SAGEM公司(法)、AD公司(美)、Vector公司(俄)等相继开展微硅陀螺、微硅加速度计等微型惯性仪表的研究,形成产品,进而进行微型惯性测量组合的研究。
  • GAO Jing, DENG Jiahao
    Science & Technology Review. 2015, 33(2): 108-112.
    Abstract (633) PDF (19454) HTML   Knowledge map   Save
    The empirical mode decomposition (EMD), that provides a multi-scale and highly adaptable method, scores a breakthrough in the signal processing field. This paper gives a brief review of research advances of the theoretical foundation of the EMD algorithm based on the concept of the EMD. Furthermore, a comparison of various improved EMD methods is made. The applications of the EMD and the directions for further research are discussed.
  • Spescial Issues
    WANG Jiyang;HU Shengbiao;PANG Zhonghe;HE Lijuan;ZHAO Ping;ZHU Chuanqing;RAO Song;TANG Xiaoyin;KONG Yanlong;LUO Lu;LI Weiwei;
    Abstract (1124) PDF (19328) HTML   Knowledge map   Save
    As one of the clean renewable energy, geothermal energy is very competitive. According to its genesis and exploration conditions, geothermal resources could be divided into two kinds, that is, one is hydrothermal resources and the other one is Hot Dry Rock (HDR) geothermal resources. Because of its universality and high temperature, HDR geothermal resources have great potential for projecting future development. The assessment of HDR geothermal resources potential is the base of HDR resources exploration. Here the heat flow map in the continental area of China is updated on the basis of more new heat flow data. Then the HDR geothermal resources are estimated using volume methods with a thermal physical access in the continental area of China (3 km —10 km). Results show that the total HDR geothermal energy is 20.9×106EJ, which is equivalent to standard coal of 714.9×1012t. If the recoverable energy is 2% by computing, then it is 168 times of conventional hydrothermal energy, and it is equivalent to 4,400 times of total annual energy consumption during the year of 2010 in China. Nevertheless, due to the limitation of economics and technology, the HDR geothermal resources exploration within the depth of 4km—7km accompanied with an expected temperature of 150—250 ℃ should be conducted in the near future. Several target regions for HDR geothermal resources exploration are proposed, including South Tibet, West Yunnan (Tengchong), the southeast coast of China (Zhejiang, Fujian and Guangdong), North China (BBB basin), the southeast regions of Ordos Basin (Fenwei Graben), and Northeast China (Songliao Basin). Finally, the future tasks involving geothermal resources research are listed.