The integration of farmers and nomads in northwestern China during the Han Dynasty(206 BCE ~ 220 CE) provides a crucial opportunity to reconstruct the material exchanges, formation and development of the Silk Road in ...The integration of farmers and nomads in northwestern China during the Han Dynasty(206 BCE ~ 220 CE) provides a crucial opportunity to reconstruct the material exchanges, formation and development of the Silk Road in antiquity. The subsistence strategy is arguably an effective proxy for the integration of various groups of people(e.g. farmers and nomads). In this paper, we have reported new stable isotope data from the Huangwan tombs dated to the Han dynasty in middle Gansu, which was the key juncture between the Han and Xiongnu empire, in order to fill the gap and further understand the substance strategies employed by the local people. According to the results of plant remains and stable isotopic data, millet farming, the typical agricultural activities for the Han Chinese in the Central Plains, was also the primary lifestyle for the Huangwan people in the mid Gansu. More importantly, this shows fundamentally remarkable difference from the agricultural practices in the Bronze Age Gansu Corridor, which were based on a variety of crops, including wheat, barley and millet. This major shift in the subsistence production at Huangwan can be correlated to a wider historical background in which the Han empire showed increasing political and military presence in the Gansu Corridor, indicating that local indigenous nomads followed the lifestyle of Han Chinese(e.g., millet farming), and/or the Han immigrates maintained millet farming.展开更多
Tianshanbeilu is the largest Bronze Age site in eastern Xinjiang, China. Stretching across the entire second millennium BC, it performed a prominent role in connecting the Hexi corridor, Central China and the steppe. ...Tianshanbeilu is the largest Bronze Age site in eastern Xinjiang, China. Stretching across the entire second millennium BC, it performed a prominent role in connecting the Hexi corridor, Central China and the steppe. A further insight into the metallurgical tradition and the metal supply network is of vital importance to improve our understanding of its multi-connected nature. This paper offers a new set of chemical and isotopic data on the copper-based objects at Tianshanbeilu, including alloying elements, trace elements(impurities) and lead isotopes. Combining the concentrations of arsenic and antimony reveals that arsenic was introduced to copper partially due to the use of specific minerals tethrahedrite-tennantite. Lead isotopes demonstrate that multiple sources of copper were employed at Tianshanbeilu and a majority of them are characterized by common lead, which appears rather different from those of the Central Plains and the Hexi corridor, but highly consistent with local ores. Surprisingly, one object at Tianshanbeilu contains the well-known highly radiogenic lead. This object undoubtedly marks the westernmost boundary of the distribution of the highly radiogenic lead. We also anticipate that more lead isotopic analyses in NW China will further contribute to the study of the highly radiogenic lead in Central China.展开更多
The use of lead, some of which is characterized by a highly radiogenic signature, sharply distinguishes Bronze Age China from the rest of Eurasia. Scholars have long hypothesized that silver can offer an independent p...The use of lead, some of which is characterized by a highly radiogenic signature, sharply distinguishes Bronze Age China from the rest of Eurasia. Scholars have long hypothesized that silver can offer an independent proxy to characterize lead minerals. The summary of silver distribution associated with Shang and Western Zhou bronzes in this paper reveals an important difference between the south(Sanxingdui, Hanzhong, Jinsha, Panlongcheng, Xin’gan) and the Central Plains. Correlating silver with lead content as well as with the isotopic signature indicates that south China and the Central Plains had different lead sources during the late Shang period, and also that the highly radiogenic and common lead used at Anyang come from geochemical environments which cannot be distinguished by the level of silver.展开更多
Microand nano-sized SiC/fluoroelastomer （FKM） composites were prepared by a mechanical mixing method. These composites were first characterized by a rotorless rheometer. Then the effects of micro- and nano-sized SiC...Microand nano-sized SiC/fluoroelastomer （FKM） composites were prepared by a mechanical mixing method. These composites were first characterized by a rotorless rheometer. Then the effects of micro- and nano-sized SiC on hardness, static and dynamic mechanical properties of the composites were investigated. The increasing amount of the SiC filler increased the curing efficiency of the biphenyl curing system, which was evident from the rheometric properties of the resulting composites. The tensile properties of composite increased with the increasing of micro- and nano-sized SiC content. When the micro- and nano-sized SiC content was higher than 20 phr, the composites showed almost unchanged tensile properties. The increasing of the tensile property was mainly attributed to the well dispersed micro- and nano-sized SiC particles characterized by SEM images. Compared to pure FKM, the composites exhibited a higher glass transition temperature and lower tan peak value.展开更多
Microchannel reactors usually have some microchannels with characteristic sizes(i.e., between 1 and 1000 μm). Small channel size and diversity are usually patterned in a microchannel reactor, and these features incre...Microchannel reactors usually have some microchannels with characteristic sizes(i.e., between 1 and 1000 μm). Small channel size and diversity are usually patterned in a microchannel reactor, and these features increase the surface area-to-volume ratio and driving force for heat and mass transport. Microchannel reactors are widely used in the petrochemistry, aerospace, electronics, information technology, and automotive industries, among others. According to the geometric shape of microchannels, a microchannel reactor can be classified as parallel, curved, micro-pin-fin array, bionic, or 3D network type. This review summarizes the fabrication methods of microchannel reactors, including traditional mechanical processing, chemical etching, electroforming injection molding technology, non-traditional machining, and sintering. It also presents the various applications of microchannel reactors in catalytic reactions, heat transfer, mixing, and other areas. Finally, this review describes the development and application prospects of microchannel reactors.展开更多
基金This research was supported by the Major Program of the National Natural Science Foundation of China(Grant No.419912251)National Key Research&Development Program of China(Grant No.2018YFA0606402)+2 种基金National Natural Science Foundation of China(Grant No.41871076)Strategic Priority Research Program of the Chinese Academy of Sciences,Pan-Third Pole Environment Study for a Green Silk Road(Pan-TPE)(Grant No.XDA2004010101)Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2018-43).
文摘The integration of farmers and nomads in northwestern China during the Han Dynasty(206 BCE ~ 220 CE) provides a crucial opportunity to reconstruct the material exchanges, formation and development of the Silk Road in antiquity. The subsistence strategy is arguably an effective proxy for the integration of various groups of people(e.g. farmers and nomads). In this paper, we have reported new stable isotope data from the Huangwan tombs dated to the Han dynasty in middle Gansu, which was the key juncture between the Han and Xiongnu empire, in order to fill the gap and further understand the substance strategies employed by the local people. According to the results of plant remains and stable isotopic data, millet farming, the typical agricultural activities for the Han Chinese in the Central Plains, was also the primary lifestyle for the Huangwan people in the mid Gansu. More importantly, this shows fundamentally remarkable difference from the agricultural practices in the Bronze Age Gansu Corridor, which were based on a variety of crops, including wheat, barley and millet. This major shift in the subsistence production at Huangwan can be correlated to a wider historical background in which the Han empire showed increasing political and military presence in the Gansu Corridor, indicating that local indigenous nomads followed the lifestyle of Han Chinese(e.g., millet farming), and/or the Han immigrates maintained millet farming.
基金This work is funded by ERC advanced project FLAME(Flow of Ancient Metal Across Eurasia,670010),Social Science Research Fund of Shaanxi Province China(2014H02)academic fund of Wolfson College(University of Oxford).
文摘Tianshanbeilu is the largest Bronze Age site in eastern Xinjiang, China. Stretching across the entire second millennium BC, it performed a prominent role in connecting the Hexi corridor, Central China and the steppe. A further insight into the metallurgical tradition and the metal supply network is of vital importance to improve our understanding of its multi-connected nature. This paper offers a new set of chemical and isotopic data on the copper-based objects at Tianshanbeilu, including alloying elements, trace elements(impurities) and lead isotopes. Combining the concentrations of arsenic and antimony reveals that arsenic was introduced to copper partially due to the use of specific minerals tethrahedrite-tennantite. Lead isotopes demonstrate that multiple sources of copper were employed at Tianshanbeilu and a majority of them are characterized by common lead, which appears rather different from those of the Central Plains and the Hexi corridor, but highly consistent with local ores. Surprisingly, one object at Tianshanbeilu contains the well-known highly radiogenic lead. This object undoubtedly marks the westernmost boundary of the distribution of the highly radiogenic lead. We also anticipate that more lead isotopic analyses in NW China will further contribute to the study of the highly radiogenic lead in Central China.
基金This work has been partially supported by European Research Council Horizon 2020 Advanced Project FLAME(ERC AdG 670010Flow of Metal Across Eurasia).
文摘The use of lead, some of which is characterized by a highly radiogenic signature, sharply distinguishes Bronze Age China from the rest of Eurasia. Scholars have long hypothesized that silver can offer an independent proxy to characterize lead minerals. The summary of silver distribution associated with Shang and Western Zhou bronzes in this paper reveals an important difference between the south(Sanxingdui, Hanzhong, Jinsha, Panlongcheng, Xin’gan) and the Central Plains. Correlating silver with lead content as well as with the isotopic signature indicates that south China and the Central Plains had different lead sources during the late Shang period, and also that the highly radiogenic and common lead used at Anyang come from geochemical environments which cannot be distinguished by the level of silver.
基金Funded by the National Natural Science Foundation of China(No.50979016)
文摘Microand nano-sized SiC/fluoroelastomer （FKM） composites were prepared by a mechanical mixing method. These composites were first characterized by a rotorless rheometer. Then the effects of micro- and nano-sized SiC on hardness, static and dynamic mechanical properties of the composites were investigated. The increasing amount of the SiC filler increased the curing efficiency of the biphenyl curing system, which was evident from the rheometric properties of the resulting composites. The tensile properties of composite increased with the increasing of micro- and nano-sized SiC content. When the micro- and nano-sized SiC content was higher than 20 phr, the composites showed almost unchanged tensile properties. The increasing of the tensile property was mainly attributed to the well dispersed micro- and nano-sized SiC particles characterized by SEM images. Compared to pure FKM, the composites exhibited a higher glass transition temperature and lower tan peak value.
基金supported by the National Natural Science Foundation of China(Grant No.51475397)Natural Science Foundation of Fujian Province of China(Grant No.2017J06015)the Fundamental Research Fund for Central Universities,Xiamen University,China(Grant No.20720180057)
文摘Microchannel reactors usually have some microchannels with characteristic sizes(i.e., between 1 and 1000 μm). Small channel size and diversity are usually patterned in a microchannel reactor, and these features increase the surface area-to-volume ratio and driving force for heat and mass transport. Microchannel reactors are widely used in the petrochemistry, aerospace, electronics, information technology, and automotive industries, among others. According to the geometric shape of microchannels, a microchannel reactor can be classified as parallel, curved, micro-pin-fin array, bionic, or 3D network type. This review summarizes the fabrication methods of microchannel reactors, including traditional mechanical processing, chemical etching, electroforming injection molding technology, non-traditional machining, and sintering. It also presents the various applications of microchannel reactors in catalytic reactions, heat transfer, mixing, and other areas. Finally, this review describes the development and application prospects of microchannel reactors.
