第三空间:旅游凝视下文化表演的意义重解——以九寨沟藏羌歌舞表演《高原红》为例

在旅游凝视力的作用下,专为游客生产的民族文化表演,通过对原生文化符号的选取、抽离、改造等不同建构方式,成为了族群传统文化与主流消费文化相遇及意义重生的空间。本文以九寨沟藏羌歌舞表演《高原红》为例,在借用西方人文科学领域中"第三空间"理论的基础上,通过对表演生成特征、功能价值、属性定位的分析,从文化人类学的角度重新阐释旅游语境中《高原红》的文化意义,指出旅游表演《高原红》所展示出的文化,既不同于主流大众文化也不同于民族传统文化,而是一种在自我与他者互动中杂糅生成的第三性异质文化,表现为民族传统文化自我的现代性表述与主动建构。

Defect‐rich BN‐supported Cu with superior dispersion for ethanol conversion to aldehyde and hydrogen

Copper‐based heterogeneous catalysts commonly exhibit uncontrolled growth of copper species under reaction conditions because of the low Hüttig temperature(surface mobility of atoms)and Tamman temperature(bulk mobility)for copper at just 134 and 405°C,respectively.Herein,we report the use of defect‐enriched hexagonal boron nitride nanosheets(BNSs)as a support to anchor the Cu species,which resulted in superior dispersion of the Cu species.The obtained Cu/BNS catalyst was highly stable for ethanol dehydrogenation,with a high selectivity of 98%for producing acetaldehyde and an exceptionally high acetaldehyde productivity of 7.33 g_(AcH) g_(cat)^(‒1) h^(‒1) under a weight hourly space velocity of 9.6 g_(EtOH) g_(cat)^(‒1) h^(‒1).The overall performance of our designed catalyst far exceeded that of most reported heterogeneous catalysts in terms of the stability of the Cu species and the yield of acetaldehyde in this reaction.The hydroxyl groups at the defect edges of BNS were responsible for the stabilization of the copper species,and the metal‐support interaction was reinforced through charge transfer,as evidenced by coupling atomic resolution images with probe molecule infrared spectroscopy and X‐ray photoelectron spectroscopy.A designed in situ diffuse reflectance infrared Fourier transform spectroscopy study of ethanol/acetaldehyde adsorption further revealed that Cu/BNS favored ethanol adsorption while suppressing acetaldehyde adsorption and further side reactions.This study demonstrates a new method for designing highly dispersed Cu‐based catalysts with high durability.

Geochemistry of Trace and Rare Earth Elements in Red Soils from the Dongting Lake Area and Its Environmental Significance

Trace element(TE) and rare earth element(REE) contents in red soils from the Dongting Lake area of China were determined to understanding the provenance and weathering characteristics of the red soils.The results showed similar REE distribution patterns among red soils from the Dongting Lake area,Xiashu loess from Zhenjiang,loess and Pliocene red soil from the Loess Plateau.These patterns implied a similar provenance from dust-storms,except for red soil R5 which formed by bedrock weathering and had significant light REE(LREE) enrichment and heavy REE(HREE) depletion due to longer weathering periods and higher intensity of weathering.Trace element,especially the Rb/Sr and Li/Ba ratios,and REE,especially the LREE/HREE ratio and δEu could trace weathering intensity.Higher Rb/Sr,Li/Ba,and LREE/HREE ratios and negative Eu anomalies were present in the red soils from the Dongting Lake area.The weathering intensity was in the decreasing order of R5 in the Dongting Lake area > red soils from the Dongting Lake area(including reticulate red soil,weak reticulate red soil,and homogeneous red soil formed by dust storms) > Xiashu loess from Zhenjiang > loess-paleosol and Pliocene red soil from the Loess Plateau.Variations in the TE and REE contents of soil could be effectively used to study the provenance and the weathering intensity.

New eolian red clay sequence on the western Chinese Loess Plateau linked to onset of Asian desertification about 25 Ma ago

The expansion of inland Asia deserts has considerably influenced the environmental, social and economic activities in Asia. Aridification of inland Asia, especially timing of the initiation of Asian desertification, is a contentious topic in paleoclimatology. Late Cenozoic eolian loess-red clay sequences on the Chinese Loess Plateau, which possess abundant paleoclimatic and paleo-environmental information, can be regarded as an indicator of inland Asia desertification. Here we present a detailed magnetostratigraphic investigation of a new red clay sequence about 654 m in Zhuanglang located at the western Chinese Loess Plateau. Sedimentological, geochemical, mineralogical, and quartz morphological lines of evidence show that the red clay is of eolian origin. Magnetostratigraphic correlations indicate that this core sequence spans from 25.6 to 4.8 Ma, and typical eolian red clay appears as early as 25 Ma. This extends the lower limit of the red clay on the Chinese Loess Plateau from the previously thought early Miocene back into the late Oligocene. This new red clay record further implies that the inland Asia desertification was initiated at least by the late Oligocene. This sequence provides a unique high-resolution geological record for understanding the inland Asia desertification process since the late Oligocene.

Response of Plant Growth and Biomass Accumulation to Short-term Experimental Warming in a Highland Barley System of the Tibet

Highland barley is an important staple food in the Tibet,and the Tibetan Plateau is experiencing obvious climatic warming.However,few studies have examined the warming effects on highland barley growth and biomass allocation under conditions of controlled experimental warming.This limits our ability to predict how highland barley will change as the climate changes in the future.An experiment of field warming at two magnitudes was performed in a highland barley system of the Tibet beginning in late May,2014.Infrared heaters were used to increase soil temperature.At the end of the warming experiment（September 14,2014）,plant growth parameters（plant height,basal diameter,shoot length and leaf number）,biomass accumulation parameters（total biomass,root biomass,stem biomass,leaf biomass and spike biomass）,and carbon and nitrogen concentration parameters（carbon concentration,nitrogen concentration,the ratio of carbon to nitrogen concentration in root,stem,leaf and spike）were sampled.The low-and high-level experimental warming significantly increased soil perimental warming did not significantly change.The low-and high-level experimental warming did not significantly affect plant growth parameters,biomass accumulation parameters,and carbon and nitrogen concentration parameters.There were also no significant differences of plant growth parameters,biomass accumulation parameters,and carbon and nitrogen concentration parameters between the low-and high-level experimental warming.Our findings suggest that the response of highland barley growth,total and component biomass accumulation,and carbon and nitrogen concentration to warming did not linearly change with warming magnitude in the Tibet.

High-sensitivity shortwave infrared photodetectors of metal-organic frameworks integrated on 2D layered materials

Photodetectors operating in the shortwave infrared region are of great significance due to their extensive applications in both commercial and military fields.Narrowbandgap two-dimensional layered materials(2DLMs)are considered as the promising candidates for constructing nextgeneration high-performance infrared photodetectors.Nevertheless,the performance of 2DLMs-based photodetectors can hardly satisfy the requirements of practical applications due to their weak optical absorption.In the present study,a strategy was proposed to design high-performance shortwave infrared photodetectors by integrating metalorganic frameworks(MOFs)nanoparticles with excellent optical absorption characteristics and 2DLM with high mobility.Further,this study demonstrated the practicability of this strategy in a MOF/2DLM(Ni-CAT-1/Bi_(2)Se_(3))hybrid heterojunction photodetector.Due to the transfer of photo-generated carriers from the MOF to Bi_(2)Se_(3),the MOF nanoparticles integrated on the Bi_(2)Se_(3) layer can increase the photocurrent by 2-3 orders of magnitude.The resulting photodetector presented a high responsivity of 4725 A W^(−1) and a superior detectivity of 3.5×10^(13) Jones at 1500 nm.The outstanding performance of the hybrid heterojunction arises from the synergistic function of the enhanced optical absorption and photogating effect.In addition,the proposed device construction strategy combining MOF photosensitive materials with 2DLMs shows a high potential for the future high-performance shortwave infrared photodetectors.

High-pressure experimental verification of rutile-ilmenite oxybarometer: Implications for the redox state of the subduction zone

The more oxidized mantle peridotites above subducting slabs than stable continental areas have been attributed to the infiltration of some oxidizing fluids released from the subducting slabs. However, knowledge for the redox states of the slabs itself is very limited. Until now, few oxybarometers can be directly used to constrain the redox states of the subducting slabs.The rutile-ilmenite oxybarometer was proposed and successfully applied to constrain the oxygen fugacity of mantle assemblages.However, its application to rocks equilibrated at crustal P-T conditions has been hampered by some uncertainties in an early solid solution model of ilmenite. With a newly-released solid solution model for the ilmenite, we have conducted high-P experiments(at 3 and 5 GPa, and 900–1300°C) to test the accuracy of this oxybarometer. The experiments were performed with their oxygen fugacities controlled by the CCO buffer(i.e., C+O_2=CO_2). We demonstrated that the oxygen fugacities calculated for our high-P experimental products by using the rutile-ilmenite oxybarometer were in excellent agreement with the fO_2 dictated by the CCO buffer, suggesting a wide applicability of this oxybarometer to crust rocks. As examples, the rutile-ilmenite oxybarometer has been used to constrain the oxygen fugacities of some metamorphic rocks such as eclogite, granulite and amphibolite usually observed from the subduction zones.