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The desert in northern China is one of important sources of loess and one significant source of material for sandstorms in Asia. The sand/dust that is transported from desert when sandstorms occur can destroy the growth of crops, cause serious losses and great harm to the economic construction and life safety, and cause natural environment pollution. Hence, it is very important to deepen the research into heavy metals in surface deposits at vulnerable ecological region of arid land of northern China to guide local industrial and agricultural development and improve environmental protection. In this research, 10 heavy metal elements (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, and Th) were tested and analyzed in 33 soil sample sites collected from the hinterland of the Tengger Desert, northern China. The results showed that the average abundance of Th exceeded its background soil value of China by more than 5.2 times, which suggests that the Tengger Desert is polluted by Th. In addition, based on principal component analysis, spatial differentiation, and correlation analysis, we identified the source of element with a coefficient of variation in abundance of greater than 0.5 or exceeding the background soil value of China. Principal component analysis and correlation analysis showed that the sources of heavy metals of Cr, Mn, Fe, Co, Ni, Cu, and Cd were similar, while those of Th and Zn were different. Moreover, based on the contents and spatial distribution characteristics of those heavy metal elements, we found that the formation of heavy metal elements enrichment areas is caused by industrial pollution, development of irrigated agricultural, geological, and geomorphic conditions, and the sedimentary environment in the study area. Our result can provide information on the environmental background values of soils in the hinterland of the Tengger Desert.

The Miocene–Holocene Red Clay, paleosol, and loess sequences composing the Chinese Loess Plateau (CLP) are one of the most complete terrestrial eolian sediment archives on Earth. We present the first large-n detrital zircon U-Pb geochronology dataset for the Miocene–Pliocene sequence from the northeastern CLP. The depositional ages of these samples are like those of other data sets from the central CLP, allowing comparison of spatial-temporal differences. These data show that the CLP had spatially varied provenance over the late Miocene–Pliocene, similar to the Quaternary strata. The data from the northeastern CLP indicate two shifts in dust sourcing around the Miocene-Pliocene and Pliocene-Quaternary boundaries. The shift around the Miocene-Pliocene boundary is consistent with elongation of the proto-Yellow River to incorporate the present-day ‘big bend’—allowing sediment transport to and ultimately through the Yinchuan-Hetao graben. The provenance shift around the Pliocene-Quaternary boundary is consistent with increased sediment contributions from the Lüliang Shan and the Cretaceous strata overlying the North China Craton. These interpretations challenge assertions linking eolian sediment accumulation on the CLP over the late Miocene–Pliocene primarily to aridification within the continental interior of eastern Asia, but rather point to the importance of riverine transport, catchment reorganization, sediment storage, and increased climatic fluctuations.

Loess sequences of the Chinese Loess Plateau (CLP) compose one of the most complete Neogene–Quaternary terrestrial paleoclimatic archives. Understanding the CLP's sediment sources is critical to tracing Asian aridification, atmospheric circulation patterns, and Asian monsoon evolution. Commonly, the sediments that compose the Quaternary strata of the CLP are considered largely homogeneous, and thus numerous studies have applied a uniform source model when attempting to use CLP-derived proxies as paleoclimate indicators. Here we present large-n detrital zircon U-Pb geochronology data from the Quaternary CLP. These data support spatial variability in sediment provenance across the CLP. At least three distinct provenance zones are recognized for Quaternary loess strata: central western, eastern, and northeastern. These zones received sediment primarily from their neighboring river systems. This finding conflicts with the classic views that attribute the Quaternary loess principally to the deserts north and west of the CLP. We conclude that fluvial processes, and thus precipitation, played an important and previously underemphasized role in Quaternary dust production in northern China. Furthermore, nonuniformity in CLP Quaternary sediment provenance raises questions about the validity of using paleoclimate information archived in the CLP to make sweeping regional interpretations.

This paper presents the development of an experimental stand for the registration of time-averaged geometric circular moiré images. Optical interpretation of patterns of time-averaged moiré fringes allows to identify the parameters of circularly vibrating structures. The developed scheme has a strong potential for designing experimental schemes capable to measure angular vibrations of rotating shafts in different mechanisms, and do not require any mountable sensors.

Despite decades of study, the factors that controlled the formation and evolution of theupper reaches of the Yellow River, including uplift of the northeastern Tibetan Plateau, Pliocene-Pleistocene climate change, and autogenetic processes are still poorly constrained. The stratigraphicrecord of such paleogeographic evolution is recorded in the sequence of nine terraces formed duringprogressive incision of the Yellow River in the last 1.7 Ma. This article investigates in detail forsediment provenance in terraces of the Lanzhou area, based on heavy-mineral and geochemical(REE) signatures. Two main provenance changes are identified, pointing each to a majorpaleogeographic reorganization coupled with expansion of the upper Yellow River catchment andenhanced sediment fluxes. The first change took place between the deposition of terrace T9 (formedaround 1.7 Ma) and terrace T8 (formed around 1.5 Ma), when rapid fluvial incision point to tectoniccontrol and active uplift of northeastern Tibetan Plateau. The second change took place betweendeposition of terrace T4 (formed around 0.86 Ma) and terrace T3 (formed around 0.14 Ma), duringa period of low incision rates and notably enhanced sediment fluxes as a response to enhanced EastAsian Summer Monsoon and consequently increased precipitations, pointing instead chiefly toclimatic control.

The upper Yellow River drains the central and northeastern Tibetan Plateau. Understanding the origin of this river is essential for unraveling the interplay between fluvial incision, basement uplift, and climate change. However, the formation age of the upper Yellow River is highly debated, with estimates ranging from Eocene to late Pleistocene. In order to clarify the history of the upper Yellow River, we present a heavy-mineral dataset from drill core in the Yinchuan Basin, a depositional sink at the end of the upper Yellow River course. Our results reveal that the drainage area of the upper Yellow River (i.e., northeastern Tibetan Plateau) has been serving as a major sediment source region for the Yinchuan Basin since at least 3.3 Ma. A late Pleistocene formation of the upper Yellow River, and erosion of neighboring deserts or bounding mountains as an explanation for thick sediment accumulations in this area, is thus ruled out.

Green innovation, which has spatial spillover effects, is a crucial way to accelerate the transformation and upgrading of urban economic structure, then to achieve sustainable development for the urban in China. Therefore, it is meaningful to study the effects of urban green innovation on economic development quality (EDQ). In this paper, using the panel data of 270 cities during 2005–2017 in China, we investigated spatial effect and effect decomposition result of green innovation on EDQ by applying Spatial Durbin Model (SDM). The results revealed that both green innovation and EDQ had demonstrated a trend of regional agglomeration and fluctuating development; the coefficient of direct effect and spatial spillover effect of green innovation on EDQ is significantly positive, green innovation is conducive to enhance EDQ in local city and adjacent cities. Therefore, it is necessary to put forward green innovation policy recommendations for around sustainable development.

QEMSCAN-based (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) heavy mineral analysis has recently been demonstrated an efficient way to allow a rapid extraction of provenance information from sediments. However, one key issue to correctly obtain a provenance signal using this technique is to clearly separate effects of diagenetic alteration on heavy minerals in sediments, especially in fine-grained loess. Here we compare heavy mineral assemblages of bottom Quaternary loess (L33) and upper Pliocene Red Clay of three sites on the Chinese Loess Plateau (CLP). Two sites (Chaona and Luochuan) with similar modern climate conditions show similar heavy mineral assemblages but contain much less of the unstable heavy mineral amphibole than the drier Xifeng site. This result provides strong evidence supporting that climate-caused diagenesis is an important factor controlling heavy mineral assemblages of fine-grained loess. However, heavy mineral assemblages are similar for loess and paleosol layers deposited after 0.5 Ma on the Chinese Loess Plateau regardless of climate differences, suggesting that time is also a factor controlling heavy mineral assemblages of loess and Red Clay. Our high resolution sampling of the upper Miocene-Pliocene Chaona Red Clay sequence reveals similar heavy mineral compositions with a minor amphibole content, different from the drier Xifeng site results of the same age. This result indicates that the monsoonal climate pattern might have been maintained since the late Miocene. Furthermore, it indicates that the heavy mineral method is promising in tracing provenance for sites northwest of the Xifeng site on the Loess Plateau.

Pre-Quaternary Asian dust accumulation rate increases were caused by monsoon-driven erosion increases., Theories of late Cenozoic climate cooling assume that central Asian aridification and high dust accumulation rates in the Chinese Loess Plateau and the North Pacific Ocean are genetically related. On the basis of detailed sediment provenance analysis, we show that high dust accumulation rates in the Chinese Loess Plateau and the North Pacific Ocean during the late Miocene-Pliocene were mainly caused by increased erosion in the Qilian Mountains and low-elevation eastern Asia areas, driven by the effects of East Asian summer monsoon intensification. We conclude that precipitation-driven erosion increased dust input to the North Pacific Ocean and may have played a pivotal role in late Cenozoic climate cooling.

Understanding provenance of glacial loess and interbedded interglacial paleosol deposits on the Chinese Loess Plateau (CLP) is important to understanding paleo-atmospheric circulation patterns. However, great debate exists about whether Chinese loess and paleosol deposits have similar provenance both spatially and temporally. Here we report heavy mineral assemblage results of two sets of loess–paleosol couplets (L1 and S1; L4 and S4) from western CLP based on scanning electron microscopy with linked energy dispersive spectrometers (SEM–EDS) analysis (QEMSCAN@). The results demonstrate no apparent provenance shift on the CLP between glacial and interglacial periods. Heavy mineral assemblage comparison between the western and the central CLP reveals no provenance shift spatially, either. Finally, a comparison of heavy mineral assemblage between loess–paleosol and potential source regions reveals that the western Mu Us desert, the Badain Jaran desert, the Ulan Buh desert as well as the Yellow river are likely key dust contributors for the CLP. In contrast, the northeastern Mu Us desert are less likely key dust sources for the CLP. The ultimate provenance history of the CLP relies no doubt on integrated provenance studies. However, due to its rapidity and robustness, integrated provenance analysis should incorporate the QEMSCAN-based heavy mineral analysis.

Single grain zircon U-Pb geochronology has demonstrated great potentials in extracting tectonic and atmospheric circulation signal carried by aeolian, fluvial, and fluviolacustrine sediments. A routine in this sort of studies is analyzing 100–150 grains and then compares zircon U-Pb age spectra between the measured sample and the potential sources. Here we compared the zircon U-Pb age results of the late Miocene-Pliocene Red Clay sequence of two neighboring sites from the Chinese Loess Plateau where similar provenance signal is expected. Although the results from the 5.5 Ma sediment support this prediction, the results from the 3 Ma sediment at these two sites differ from each other significantly. These results emphasize the importance of increasing analysis number per sample and combining the zircon U-Pb geochronology with other provenance tools in order to get reliable provenance information.

In recent Western and Chinese scholarship on discourses of ethnicity in south-west China, there has been an emergent interest in the mechanism of memory and forgetting in relation to formations of ethnicities and frontier space. In Southwest China, perhaps no figure has been more important than Zhuge Liang, a famous strategist during the Three Kingdom Period (220–280 AD), whose Nanzheng (Southern Expeditions) military operation left many legends among ethnic minorities in the region, often associated with the origins of a multiplicity of place names and cultural attributes. However, in the melodrama of ethnic unity after 1949, Zhuge Liang has been championed as a benevolent figure whose ethnic policy successfully transformed the historically volatile southwestern minority regions and brought them into the fold of the Chinese nation. Based on archives and oral interviews, this paper examines the twists and turns in official and indigenous interpretations of Zhuge Liang's legacies in southwest China. It analyses oral traditions of Zhuge Liang in the Tibetan border city of Kangding as well as in Yi and Han places. The paper intends to highlight individual and specific aspects related to the construction of frontier space and memory in conjunction with the negotiation and contestation of visions of local and official histories.

A novel combined cryptographic and hash algorithm based on chaotic control character is proposed in this paper. The control character is generated by chaotic iteration. The plaintext is pre-processed in terms of control character, and then encrypted by the look-up index table. At the same time, the chaotic trajectory is changed continuously according to the control character, which can avoid the dynamical degradation of chaos. Besides, the look-up index table is updated by utilizing the control character continuously, and the index item of the final look-up index table can be considered as the hash value of the whole paragraph of plaintext. Therefore, the proposed algorithm can perform both encryption/decryption and hash in a combined manner. Compared with Wong’s and our former algorithms, the proposed one has decreased the ratio of ciphertext/plaintext to 1, and improved the efficiency greatly. Theoretical analysis and computer simulation verify the validity of the proposed algorithm.

Marine accumulations of terrigenous sediment are widely assumed to accurately record climatic- and tectonic-controlled mountain denudation and play an important role in understanding late Cenozoic mountain uplift and global cooling. Underpinning this is the assumption that the majority of sediment eroded from hinterland orogenic belts is transported to and ultimately stored in marine basins with little lag between erosion and deposition. Here we use a detailed and multi-technique sedimentary provenance dataset from the Yellow River to show that substantial amounts of sediment eroded from Northeast Tibet and carried by the river's upper reach are stored in the Chinese Loess Plateau and the western Mu Us desert. This finding revises our understanding of the origin of the Chinese Loess Plateau and provides a potential solution for mismatches between late Cenozoic terrestrial sedimentation and marine geochemistry records, as well as between global CO2 and erosion records., Theories of Cenozoic mountain uplift and associated global cooling assume that eroded mountain sediments are stored in marine basins. Here, based on detailed provenance data, Nie et al. show that Northeast Tibetan sediments are in fact stored inland, in the Chinese Loess Plateau and Mu Us desert.

The original version of this Article contained errors in the Supplementary Information files: Zircon U-Pb age results for sample 23, shown in Supplementary Fig. 3, are incorrect, and missing from Supplementary Data 1, while several identification labels relating to Yellow River Lanzhou terraces samples are missing from Supplementary Data 2. Supplementary Data 1 and 2 have now been updated to provide the missing information, while the corrected version of Supplementary Fig. 3 appears below.

Co/Pd superlattice perpendicular films are fabricated on 2 nm indium tin oxide (ITO) seed layers by DC magnetron sputtering. A film with perfect remanent squareness and highly linear demagnetization shear is obtained. Micromagnetic simulation suggests that the film has weak intergranular exchange coupling. Good SNR is obtained, but D50 is reduced by the closely spaced soft underlayer and large fly height.

Heavy-mineral analysis is a sensitive technique in constraining provenance of sandstone, but has rarely been applied to loess. Here we report a heavy-mineral study of selected samples from the Luochuan, Xifeng and Caoxian loess-Red Clay sections on the Chinese Loess Plateau, based on the novel QEMSCAN (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) technique. We found that heavy mineral assemblages of loess deposited through the past 500. kyr are similar and unchanged by post-depositional chemical dissolution. In contrast, in samples deposited from 900. ka to 3. Ma, the relative proportion of stable minerals tends to increase down section. In addition, the Xifeng samples consistently display higher contents of unstable ferromagnesian minerals than the Luochuan samples. Detailed analysis of surface textures displayed by different minerals by optical methods indicates that such a compositional difference can be ascribed to more effective diagenetic dissolution for the Luochuan section, explained by more extensive percolation of interstitial waters in wetter climatic conditions. Interestingly, heavy-mineral assemblages in the underlying upper Miocene Red Clay from Xifeng (deposition age. ~. 7. Ma) are similar to those of recent loess deposited since 500. ka. This similarity indicates that climate and/or local preservation conditions hampered dissolution reactions, thus helping to preserve an original provenance signal that remained largely unchanged throughout the considered time period. Our study demonstrates that climatically- and time-controlled diagenesis plays a key role in determining the composition of heavy-mineral assemblages contained in loess deposited several hundreds of thousands years ago. We also show that by using both QEMSCAN and traditional optical techniques on the same samples we can obtain fundamental complementary information for a correct interpretation of the heavy-mineral assemblage. © 2013 Elsevier B.V.

Co/Pd and Co/Pt multilayers have been fabricated on ultra-thin (2 nm) indium tin oxide (ITO) seed layers with soft underlayer for perpendicular magnetic recording. The coercivity of the Co/Pd multilayers was increased from 5.1 kOe to 6.3 kOe by increasing the thickness of the initial Pd layer from 1 nm to 2 nm. Hysteresis loops with an almost perfect remanent squareness, high nucleation field, and more sheared sides were obtained. TEM analysis shows that the films have well-segregated columnar structures which help to reduce exchange coupling and increase coercivity. Spin-stand testing shows that the Co/Pd multilayers have a D50 about 157 kfci without differentiating the output signals. Co/Pt multilayers with ITO seed layers deposited in 40 mTorr of Kr give a coercivity of 6.9 kOe and a D50 about 290 kfci when the output signal is differentiated.

Co/Pd superlattices (13 bilayers) have been fabricated on ultrathin (2 nm) indium–tin–oxide (ITO) seed layers for use as perpendicular magnetic recording media. The ITO seed layers have significantly increased the coercivity from 1 to 5 kOe as well as the crystalline orientation texture. It was also found that excellent magnetic properties could be obtained by using Ar instead of Kr as sputtering gas. The sheared hysteresis loop and high squareness suggest weak intergranular coupling and adequate perpendicular magnetic anisotropy which make Co/Pd supelattice a promising candidate for ultrahigh recording densities with thermal stability.

Co/Pt superlattices with an ultra-thin amorphous Ta seed layer on a Ni/sub 45/Fe/sub 55/ underlayer were fabricated for double-layer perpendicular magnetic recording media using a special hard disk sputtering system with a triple-target DC magnetron cathode (Triatron). A 2.5 nm thick Ta seed layer was found to improve the crystalline structure and increase the coercivity of the Co/Pt superlattices from 1.13 to 2.17 kOe. A 2.5 nm Ta layer on a 200 nm thick magnetically soft NiFe underlayer was found to further increase the coercivity from 2.25 to 5 kOe. In addition, the sheared slope of the sides of hysteresis loop of Co/Pt superlattices was significantly improved from about 5 Gauss/Oe (with only a 2.5 nm Ta seed layer) to about 1.1 Gauss/Oe (with both a 2.5 nm Ta seed layer and a 200 nm NiFe underlayer).

Mn and Cu overlayers were studied with CoCrTaPt/Cr films on glass substrates. Low temperature postannealing reveals an increase in the in-plane coercivity of 700 Oe for Mn and 400 Oe for Cu. X-ray diffraction patterns indicate that the change in magnetic properties is unlikely due to the improvement of crystalline structure. It is suggested that the interdiffusion between magnetic layer and overlayer plays a key role in the coercivity increase. ΔM curves show reduced exchange coupling between grains. It is believed that during low temperature annealing, the diffusion of the overlayer atoms most likely occurs at the grain boundaries, which results in better segregation between grains that may lead to higher coercivity and lower media noise.

CoB/Pd multilayers have been fabricated on ultrathin (2 nm) indium tin oxide seed layers with NiFe soft underlayer for perpendicular magnetic recording. In situ heating to 230 °C was applied to increase the mobility of the boron atoms so that they can presumably migrate to the grain boundaries to promote grain segregation and inhibit grain growth. It gave a coercivity of 5 kOe and a D50 about 330 kfci for differentiated output signals. Magnetic force microscopy analysis shows that the magnetic domain size has been decreased due to the addition of B in Co layer, which may lead to better recording performances. An areal density of 11 Gb/in2 was achieved at a bit-error-rate of 10−6. As the recording was limited by the wide track width of the head, high flying height, and noisy soft underlayer, it is expected that the media has the potential of more than 30 Gb/in2 in areal density.