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Table of Content

    25 February 2019, Volume 41 Issue 1
    Review Article
    Measurement and control of ultrafast dynamics in molecules
    LI Hui, WU Jian
    2019, 41(1):  1-7.  doi:10.3969/j.issn.0253-9608.2019.01.001
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    Molecules are the basic unit of materials. Revealing the dynamic process inside molecules is an indispensable means to understand macroscopic physical mechanisms and achieve effective manipulation. The rapid development of ultra fast laser technology and coincident detection method allow us to observe the ultrafast dynamics inside molecules. The continuous innovation of technology has pushed the research of molecular ultrafast dynamics to a new frontier.

    An introduction of ultracold strongly interacting Fermi gases
    DENG Shujin, WU Haibin
    2019, 41(1):  8-14.  doi:10.3969/j.issn.0253-9608.2019.01.002
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    An ultracold Fermi gas provides an ideal system to study many-body physics. It could be used as a remarkable test-bed to study many strongly-coupled phenomena, such as high-temperature superconductors, quark-gluon plasma and neutron stars. The ability of precisely controllable interactions and external potential enables us to explore the exotic phase with quantum matter, investigate the quantum non-equilibrium thermodynamics, ultracold collisions and many-body physics in strongly-coupled system. In this paper, we will introduce our recent research on the scale invariant Fermi gases, such as the Efimovian expansion dynamics and the progress of many-body quantum heat engine.

    Fiber optical frequency comb
    XIE Gehui, LIU Yang, LUO Daping, ZHU Zhiwei, DENG Zejiang, GU Chenglin, LI Wenxue
    2019, 41(1):  15-23.  doi:10.3969/j.issn.0253-9608.2019.01.003
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    In temporal, an optical frequency comb (OFC) can be described as an ultrashort pulse train with a constant time interval, possessing a femtosecond pulse duration and an extremely high instantaneous electric field. In spectral, an OFC can be depicted as a comb-like aggregation of millions of frequency teeth with a constant frequency interval, and every single frequency tooth of the comb has an extremely narrow linewidth and a high frequency accuracy as a narrow-line-width CW laser owns. With the advance of fiber technology, the fiber OFC has been developed into an important tool in many scientific research fields such as high-precision feature information recognition of atom and molecular, internal structure analysis of matter, biological imaging and remote-sensing space imaging. In this paper, we present the basic technical principles of optical comb, and some progresses in the field of OFC achieved by LPS ECNU are introduced. Especially, based on the homemade fiber OFCs, two proposed applications including dual-comb 3D coding imaging and dual-comb molecular spectral imaging are demonstrated in detail.

    Laser distance measurement based on single-photon detection
    LI Zhaohui, WU Guang
    2019, 41(1):  24-28.  doi:10.3969/j.issn.0253-9608.2019.01.004
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    Laser distance measurement is widely used in scientific research and industrial application. Non-contact and high precision distance measurement can be realized by measuring the time, phase, frequency, polarization and intensity of laser. Single-photon detection improves the sensitivity of photoelectric direct detection to the limit of single photon, greatly improves the ability of the laser distance measurement, so we can see farther. We have achieved long-distance and high-precision laser three-dimensional imaging through developing high-speed, multi-channel, and high-precision single photon detectors.

    Sub-hertz-linewidth frequency-stabilized lasers
    JIANG Yanyi, BI Zhiyi, MA Longsheng
    2019, 41(1):  29-34.  doi:10.3969/j.issn.0253-9608.2019.01.005
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    Lasers are widely used in precision spectroscopy and precision measurement. The laser frequency stability and spectral purity determine the measurement accuracy and precision. Therefore, lasers with even higher frequency stability and narrower linewidth are pursued. In this paper, we review the techniques of sub-hertz-linewidth lasers and prospect the ways to realize lasers even higher frequency stability.

    Progress
    Artificial brains and neuromorphic engineering
    GU Fanji
    2019, 41(1):  35-43.  doi:10.3969/j.issn.0253-9608.2019.01.006
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    A review on the history and state of the art of artificial brains and neuromorphic engineering is given in this paper. An argument on the necessity and feasibility of faithfully copying a whole human brain is also given.

    Metal deposits, oil and gas reservoirs: two brothers in sedimentary basin
    HU Yuzhao, REN Tao
    2019, 41(1):  44-48.  doi:10.3969/j.issn.0253-9608.2019.01.007
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    More and more evidences revealed that a large number of asphalt remnants or oil and gas reservoirs were found in the metal deposits. Meanwhile organic components such as methane and ethane were detected in fluid inclusions of the metal ore. Even oil were detected from some fluid inclusions on metal deposits. And high content of metal elements were also identified in oil. Nevertheless, for a long time, most researchers have separately studied metal deposits or oil and gas reservoirs in sedimentary basins. In this study, the spatial, genetic and temporal relationships between metal deposits and oil and gas reservoirs in sedimentary basins are discussed. It is considered that the formation of the above-mentioned deposits in the basin was a response to the same orogenic event. Under tectonic stress, ore-forming fluids, oil and gas migrated along higher permeable pathways (e.g., fault, unconformity and rock) in sedimentary cover and later oil-gas reservoir and ore deposit are successively formed in uplift position and other traps. This understanding is also a guiding to the exploration of metal deposits and oil and gas reservoirs in sedimentary basins.

    Recent progress of AVS
    ZHAO Haiwu, LI Xiang, LI Guoping, TENG Guowei, WANG Guozhong
    2019, 41(1):  49-55.  doi:10.3969/j.issn.0253-9608.2019.01.008
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    Audio video coding standard (AVS) is the typical case of China’s implementation of independent innovation strategy. Two generations of standards have been completed since the AVS working group is established in 2002. The first generation AVS standard was been widely used in the field of digital television broadcasting. The performance of the second generation standard was surpassed the international standards of the same generation, and the third generation standard is brewing.This paper briefly reviews the production of AVS standards, and then introduces the progress of AVS1/AVS+, AVS2 and AVS3.

    History of Natural Science
    The movement of molecular motors: sliding movement of life
    GUO Xiaoqiang
    2019, 41(1):  56-62.  doi:10.3969/j.issn.0253-9608.2019.01.009
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    Life is movement, so movement of molecular motors is essential for many life processes. Myosin, dynesin and kinesin are three important kinds of molecular motors, responsible for muscle and non-muscle cell movement. Sliding movement between myosin and actin is the molecular basis of muscle contraction. Kinesins and dyneins, which move directionally along microtubules, play essential roles in intracellular transport, separation of the chromosomes during mitosis and meiosis, and cytoskeletal dynamics. The mutations and deficiencies of molecular motors can lead to disease, such as inherited neuropathies, severe myopathies and chronic infections of the respiratory tract. Therefore, the study of molecular motors provides a new strategy for the treatment of many diseases. In this article, the discovery, biological roles and application of molecular motors are comprehensively reviewed.

    Natural Forum
    Why the global plates can migrate?
    WAN Tianfeng,YIN Yanhong
    2019, 41(1):  63-70.  doi:10.3969/j.issn.0253-9608.2019.01.010
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    The dynamics of global plate migration is a very interesting project, but never solved in last fifty years. Many researchers thought that the plates must be migrated by the mantle “transporter model”, but that was not true. Due to the most of geological data were hidden in the earth, however, in the last 200 million years the geological data were more emerged, thus let us to discuss the seven models of the dynamics of global plate migrations. The authors proposed a new plate tectonic dynamics hypothesis for last 200 Ma. The solar system penetrated the galactic (Milky Way) plane in each 33 Ma and let the giant meteorites impact the Earth on the different areas with different angles to form the different plate migration models. According to this new hypothesis, the meteorite impact on Earth is a result of interplanetary gravity change in the solar system.

    Science Review
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