ISSN 0253-2778

CN 34-1054/N

2013 Vol. 43, No. 11

Display Method:
Theoretical method for open quantum systems: Progresses and perspectives
YAN Yijing
2013, 43(11): 861-869. doi: 10.3969/j.issn.0253-2778.2013.11.001
The hierarchical equations of motion (HEOM) formalism developed recently is becoming an important method for investigating the properties and dynamical processes of quantum open systems. A comprehensive account on its establishment and recent development was given, covering theoretical formulations, numerical algorithm and practical applications. By construction HEOM resolves in a nonperturbative manner the combined effects of many-body interaction, system-environment coupling and non-Markovian memory. While it is mathematically equivalent to an exact path integral formalism, HEOM is also very convenient in computation and versatile in various systems of study. Moreover, it is shown recently that HEOM is actually a correlated system-environment dynamics theory. The practicality of HEOM to address physical and chemical problems was exemplified with examples relevant to quantum dissipation and quantum transport.
Macroscopic-scale nanowire assemblies and their functionalities
LIU Jianwei, LIANG Haiwei, YU Shuhong
2013, 43(11): 870-876. doi: 10.3969/j.issn.0253-2778.2013.11.002
Up-scale and controlled syntheses of high-quality nanowires are the basis of the fabrication of nanowire based devices and their applications. The development of facile, reliable and effective nanowire assembly techniques plays a crucial role in the applications of nanowire technology. Macroscopic-scale assemblies and their functionalization can not only improve their intrinsic properties but also create new functionalities. This paper aims at providing an overview and summary on the recent advances achieved by this lab and also our opinions on this emerging field.
Bioinspired cationic polyene cyclization
ZHANG Xiang, XU Yunhe, Loh Teck-Peng
2013, 43(11): 877-888. doi: 10.3969/j.issn.0253-2778.2013.11.003
Enzyme is one of the most powerful catalysts. It can catalyse various biochemical reactions very effectively in vivo under very mild conditions. In most cases, it exhibits high catalytic activity and results in products with perfect optical purities. One of such processes is the enzyme-catalysed synthesis of cholesterol in the biological systems for the synthesis of various terpenoids or steroids via the cationic polyene cyclization reaction. Therefore, there has been a strong interest among chemists in developing biomimetic versions of many of these biochemical transformations. This paper briefly describes the current research status of this field and our groups research contribution in this area.
Controlled synthesis of metal nanostructures for tunable catalytic activities
BAI Yu, LONG Ran, WANG Chengming, XIONG Yujie
2013, 43(11): 889-898. doi: 10.3969/j.issn.0253-2778.2013.11.004
The methodology for controlled synthesis of metal nanocrystals with a face-centered cubic (fcc) structure was summarized, illustrating the key parameters for the shape control in the synthesis. Taking the recent progress in our research group as an example, the facet control of metal nanocrystals was demonstrated. For instance, nanocrystals with various low-index facets can be rationally synthesized by selecting appropriate capping agents; the formation of high-index facets can be achieved on the surface of nanocrystals by activating specific sites for atomic addition. As various surface facets possess different atomic arrangements, they exhibit tunable properties in molecular adsorption and activation, which allow us to tailor their performance in catalysis.
SVC or not SVC, that is the question
LI Weiping
2013, 43(11): 899-906. doi: 10.3969/j.issn.0253-2778.2013.11.005
Research on scalable video coding (SVC) has been motivated by the need of transmitting video over the Internet. There have been many good research results on SVC and they are included into international standards too. This paper is an attempt to analyze the likelihood of using SVC for network video applications. From the perspective of the game theory, the conclusion is that SVC is not likely to be used in the current Internet and the future network research has to set the game rules right in order to take advantage of SVC to achieve the global optimum of network video applications.
Compressive sensing of great earthquake rupture process: Methodology and research advances
YAO Huajian
2013, 43(11): 907-921. doi: 10.3969/j.issn.0253-2778.2013.11.006
The use of observational methods to investigate great earthquake rupture processes has been one of the most important tools to study earthquake rupture physics. This review article gave a fairly detailed description about the compressive sensing technique, a method based on sparse inverse theory, and its application in studying the spatial and temporal distribution of seismic radiation at different frequencies during great earthquake ruptures. In particular, the main results about the frequency- and depth-dependent seismic radiation during rupture processes of subduction zone megathrust earthquakes that were revealed by the compressive sensing technique were reviewed as well as its correlation with depth-dependent co-seismic slip and early aftershocks distribution. These may provide important observational results for understanding the frictional properties of the subducting slab interface and rupture mechanisms of subduction zone great earthquakes. Finally, the current status and future directions on studying earthquake rupture process using observational methods were discussed. Some perspective researches about the use of the compressive sensing technique for studying seismic radiation during earthquake ruptures were also discussed as well as its application in some other fields in seismology and geophysics.
A brief review of the equatorial thermosphere anomaly
LEI Jiuhou
2013, 43(11): 922-928. doi: 10.3969/j.issn.0253-2778.2013.11.007
The equatorial thermosphere anomaly (ETA), a similar phenomenon to the equatorial ionization anomaly (EIA), is a feature of the upper thermosphere with two crests at ±20~30° in magnetic latitude and a trough at the magnetic equator. Albeit the ETA was first reported in the N2 observations from the OGO6 satellite back in the 1970s, the causes of the ETA formation and its variability are not well understood. Recent studies have revealed that neither heat transport due to zonal winds nor chemical heating can explain the formation of the ETA crests. Instead, it was found that plasma-neutral collisional heating and the field-aligned ion drag are the major contributors in producing the ETA crest and trough respectively. A brief review was given on some significant achievements gained to the mechanisms of the ETA formation and questions remaining about the physical processes for the ETA variability, which should be explored in the near future.
Research progresses and prospects on reproductive toxicity of gold nanopartides
SUN Fei, LI Wenqing
2013, 43(11): 929-932. doi: 10.3969/j.issn.0253-2778.2013.11.008
Gold nanoparticles have triggered an emerging interest for research and application because of their outstanding characteristics such as easy-synthesis, easy-modification, photothermal transferring and good biocompatibility. Meanwhile, gold nanoparticles are non-degradable by organisms, which causes many researchers investigating the toxicity of gold nanoparticles. This paper focused on the reproductive toxicity of gold nanoparticles on germ cells, female and male, and posterity. The progresses and prospects of research on reproductive toxicity of gold nanoparticles were reviewed.
Small interfering RNA mediates gene regulation in the nucleus of Caenorhabditis elegans
FENG Xuezhu, GUANG Shouhong
2013, 43(11): 933-940. doi: 10.3969/j.issn.0253-2778.2013.11.009
Noncoding RNAs (ncRNAs) are widely present in higher eukaryotes and involved in a range of biological processes to regulate gene expression, genome integrity, and development. Growing evidence has emerged that ncRNAs are also involved in the generation of diseases. Small regulatory RNAs have shown potential as disease marker, drug targets, and therapeutic drugs. Our research is focused on the molecular mechanism and biological roles of small interfering RNA (siRNA)-regulated gene expression in metazoans. By conducting genetic screenings in the model organism C. elegans, a novel nuclear RNAi defective (Nrde) pathway and the critical players have been identified through which siRNA performs gene silencing in the nucleus. This work not only demonstrated that nuclear RNAi machinery exists in metazoans, but also led to several discoveries. For example, we found that small RNAs are sorted between distinct subcellular compartments by associating with particular Argonaute proteins. siRNAs regulate transcription elongation by inhibiting RNA polymerase Ⅱ and elicit premature termination. Furthermore, it was found that this pathway is necessary for the transgenerational maintenance of acquired RNAi.
A retrospective and perspective view on cross efficiency of data envelopment analysis (DEA)
LIANG Liang, WU Jie
2013, 43(11): 941-947. doi: 10.3969/j.issn.0253-2778.2013.11.010
As an important method for efficiency evaluation, data envelopment analysis (DEA) has attracted more and more attention. Cross efficiency evaluation method, as an effective method for DEA ranking, has undergone rapid development. Three aspects of the progress in cross efficiency were summarized: its non-uniqueness, aggregation and the study of game cross efficiency. Finally, a discussion was given about what can be expected of studies on cross efficiency in the near future.
Progress and perspectives in combustion chemistry
QI Fei, LI Yuyang, ZENG Meirong, ZHANG Feng
2013, 43(11): 948-958. doi: 10.3969/j.issn.0253-2778.2013.11.011
Combustion provides over four fifths of the global energy supply, and is playing an irreplaceable role in energy, transportation, defense, industries, etc. Recognizing the crucial role of chemical reactions in combustion processes, research of combustion chemistry, especially development of kinetic models, enables us to better understand the combustion phenomena, control combustion behaviors and develop novel techniques for more efficient and cleaner combustion. In recent years, the applications of novel diagnostic tools like synchrotron vacuum ultraviolet (VUV) photoionization mass spectrometry in measurements of microscale combustion structure and the development of theoretical calculation methods have greatly improved the accuracy and applicability of kinetic models, contributing to the rapid development of combustion chemistry.In this paper,recent progresses in combustion chemistry research including theoretical calculations, experimental diagnostics and model development were reviewed,and perspectives of future work in this subject were presented.
The main scientific challenges in fire safety research of nuclear power plants
HUANG Xianjia, TU Ran, YI Jianxin, XIE Qiyuan, JIANG Xi
2013, 43(11): 959-966. doi: 10.3969/j.issn.0253-2778.2013.11.012
The main scientific challenges in fire safety research of nuclear power plants were briefly summarized. Considering the fire characteristics in nuclear power plants and the bottlenecks in fundamental research especially in software R&D in China, the recent progresses in the related fields of fire safety research of nuclear power plants were reviewed. Based on the current needs and future trends in this area, some key research directions for the fire safety of nuclear power plants in China were proposed.