Loading...
中文

Table of Content

    25 August 2014, Volume 36 Issue 4
    Previous Issue    Next Issue
    Invited Special Paper
    Stellar streams and their implication for studies on the structure of our Galaxy
    ZHAO Jun-liang
    2014, 36(4):  235-240.  doi:10.3969/j.issn.0253-9608.2
    Asbtract ( 864 )   PDF (1817KB) ( 1427 )  
    Related Articles | Metrics
    Many stellar tidal streams in the outer halo of the Milky Way Galaxy have been found since 1994. Some streams are formed from dwarf satellites and others from globular clusters. More and more observational and theoretical studies on the stellar streams have been done during recent 20 years or so, from which some important results were gained.
    Comprehensive Survey
    Colorful friction, wear and lubricants
    LIU Wei-min①;GUO Zhi-guang②
    2014, 36(4):  241-247. 
    Asbtract ( 452 )   PDF (2112KB) ( 787 )  
    Related Articles | Metrics
    Friction and wear occur in everywhere, which are closely related to our life. In this paper, the foundation and development of tribology are briefly introduced, and the commonly used lubricating materials with some corresponding applications are also summarized. Many efforts have been made to improve the lubrication and antiwear properties of lubricating materials. Additionally, synthetic oils can be designed to be more effectively used in different environmental conditions, expected to replace mineral oil at many areas for more benefits such as economic applicability. Solid lubricating materials play an irreplaceable role in aerospace engineering and military area due to their good resistance to high temperature, high radiation, high vacuum, and so forth. With the progress of modern industry, physical chemistry, tribological properties and biodegradation performance of lubricating materials must meet the challenges put forward by the complicated environment and severe condition.
    Review Article
    New technology for human getting rid of friction: superlubricity
    LI Jin-jin;LUO Jian-bin
    2014, 36(4):  248-255. 
    Asbtract ( 865 )   PDF (2616KB) ( 2440 )  
    Related Articles | Metrics
    With the fast development of industry, the contradiction between consumption and scarcity of energy resources become more acute, which led to the great attention to improving the efficiency of energy utilization. Friction is one of the important ways to consume energy, but the technology of superlubricity can increase the efficiency of energy utilization greatly in sliding system. Superlubricity is a new area in tribology, in which the slide friction coefficient is about 1/1000 of the general ones or less. Since the concept of superlubricity was proposed at the beginning of the 1990s, it has attracted more and more attentions from researchers in fields of tribology, physics, chemistry, materials, etc. Theoretically, most works were focused on investigating the mechanism of superlubricity. Experimentally, great efforts have been made for finding out the properties of superlubricity materials. Many significant progresses have been made during the last two decades in studies on superlubricity. In the present work, the recent advancements in superlubricity and the application of superlubricity in the future are addressed.
    Comprehensive Survey
    Research progress and challenges in tribo-electric systems
    ZHANG Yong-zhen;YANG Zheng-hai;SHANGGUAN Bao
    2014, 36(4):  256-263. 
    Asbtract ( 587 )   PDF (2616KB) ( 2172 )  
    Related Articles | Metrics
    Performances of tribo-electric systems are determined not only by the tribological and electric behaviors of the sliding pairs, but also by their combination effects. Among those combination effects, electric arc plays very important role in contacting surface damage. Moreover, the advances and possible breaks in tribo-electric research are introduced in this paper.
    Additives: crucial condiment of lubricant
    ZHANG Sheng-mao;LIU Hao;ZHANG Ping-yu;ZHANG Zhi-jun
    2014, 36(4):  264-273. 
    Asbtract ( 498 )   PDF (3328KB) ( 1213 )  
    Related Articles | Metrics
    In this paper, we present the classification and roles of lubricant additives. When applied as lubricant additives, nanoparticles show special and excellent tribology properties. Therefore, we further summarize main types of nano lubricant additives and discuss action mechanism of nanoparticles during friction process. In addition, some analyses about the research focus and development trend of nanoparticles in lubricants are put forward combining with our work.
    Progress
    New insights into the higher-order structure of 30-nm chromatin fiber
    DONG Li-ping;CHEN Ping;LI Guo-hong
    2014, 36(4):  274-279. 
    Asbtract ( 674 )   PDF (1954KB) ( 1450 )  
    Related Articles | Metrics
    Genomic DNA in the eukaryotic cells is hierarchically folded by histones into chromatin to fit inside the nucleus. DNA wraps around the histone octamers to form nucleosomes, which are connected by linker DNA to form a “beads-on-a-string” nucleosomal array—the primary structure of chromatin. The nucleosomal array is further folded into a condensed 30-nm chromatin fiber. In past three decades, the structure of 30-nm chromatin fiber has been remained as one of the fundamental problems in molecular biology. Based on the early studies of electron microscopy, X-ray crystallography and other biophysical methods, two classic structural models have been hypothesized: the solenoid model and the zig-zag model. Here we review the recent research progresses on the structure of 30-nm chromatin fiber and focus on the recent cryo-EM study of 30-nm chromatin structure which is revealed as a left-handed double helix twisted by tetra-nucleosome units. In addition, we discuss the physiological relevance of 30-nm chromatin fiber in vivo and the perspective on its structural dynamics in epigenetic regulations.
    The flower breeding and prospects in China
    LI Xin①;SHI Yi-min②
    2014, 36(4):  280-284. 
    Asbtract ( 500 )   PDF (3207KB) ( 1449 )  
    Related Articles | Metrics
    Flowers become more and more popular because of the particular flower shape, outstanding flower color and take important part in cut flowers, potted flowers production and landscape application. In this paper, the research status of conventional breeding, mutation breeding, tissue culture breeding and molecular breeding of flowers was summarized. The existent questions and measures were presented. At last, prospects about flower breeding were discussed.
    Mathematical Essence
    The optimality of symmetry trial on optimum seeking methods
    HU Yu-da
    2014, 36(4):  285-291. 
    Asbtract ( 2787 )   PDF (1358KB) ( 1063 )  
    Related Articles | Metrics
    Optimum seeking methods are those that in practice seek to obtain approximate optimal alternatives through trials for problems with one optimum value. Approximate golden section methods, which use Fibonacci sequence or golden section number, constitute a class of methods that are most important and most often used. This paper gives the relationships of the first trial point and the maximal number of the optimality of symmetry trials of approximate golden section methods. With these relationships, the maximal number of the optimality of symmetry trials can be determined for any approximate golden section method.
    Natural Forum
    Brainbow: colorful stories
    WU Jian-young
    2014, 36(4):  292-296. 
    Asbtract ( 440 )   PDF (2809KB) ( 1058 )  
    Related Articles | Metrics
    Science Review
    Science grows up in failure
    GUAN Yi
    2014, 36(4):  297-305. 
    Asbtract ( 443 )   PDF (1646KB) ( 735 )  
    Related Articles | Metrics
    Science and Art
    Description of movement in western paintings and its scientific basis
    LIN Feng-sheng
    2014, 36(4):  306-312. 
    Asbtract ( 664 )   PDF (8667KB) ( 1950 )  
    Related Articles | Metrics
[an error occurred while processing this directive]