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Aiming at the problems of traditional equipment fault diagnosis, such as poor real-time performance, low efficiency and strong subjectivity, a method of industrial equipment sub-health status monitoring based on big data technology was proposed. Firstly, the characteristic engineering of vibration signals is formed by preprocessing vibration signals collected by sensors located near the bearing shaft. Then, the deep residual shrinkage network DRSN was used to build the classification model. By tuning the model parameters, the optimal sub-health status identification model of industrial equipment was obtained. Finally, the accuracy, robustness and generalization of the model were verified. Experimental results show that this method has better generalization performance and can significantly improve the accuracy of industrial equipment fault diagnosis, which has important theoretical value and practical significance to solve the sub-health problems of industrial equipment.

The compound Bi7O9I3 has been considered as a promising candidate for organic dye degradation in wastewater, but it has relatively low photocatalytic activity and difficulties in the recycling processes. In this work, a novel floating 3D porous Bi7O9I3/N-doped graphene aerogel (Bi7O9I3/NGA) composite was successfully synthesized through a facile hydrothermal route. The Bi7O9I3/NGA composite exhibited highly enhanced photocatalytic performance toward degrading rhodamine B under visible-light irradiation, which increased 6.0 and 2.3 times compared with the Bi7O9I3 and Bi7O9I3/GA, respectively. The enhancement of photocatalytic degradation activity could be ascribed to the extensively promoted charge generation and migration efficiency, visible light utilization ability and reactive oxygen species production. Besides, the special 3D macroscopic block structure of Bi7O9I3/NGA allowed it to float, making it easy to recycle. The photocatalytic degradation efficiency of Bi7O9I3/NGA composite still could reach up to 92.7% after four consecutive cycles and presented satisfactory stability and reusability. Moreover, a possible photocatalytic degradation mechanism was revealed by radical species trapping and semi-quantitative analyses experiments.

Four gneiss boulders on Holocene glaciofluvial fans offset by the Kongur normal fault in the Chinese Pamir Plateau were sampled to test the reliability and applicability of rock surface luminescence dating. The 10 Be ages of the boulders ranged from 2.1 to 7.5 ka. Depth profiles of luminescence intensity were measured using a modified multi-elevated-temperature post-infrared infrared stimulated luminescence (MET-pIRIR) protocol, in which two consecutive stimulations with different power, 15 and 131 mW/cm 2 , were performed for each temperature. The decay rate of the trapped charge at the surface σ φ 0 ¯ were calibrated using the 10 Be age for each boulder sample. The resulting values for the parameter σ φ 0 ¯ were utilized to estimate the exposure time of other samples. The shielding effect of rock varnish was examined in relation to the attenuation coefficient μ and the wavelength of the sunlight that penetrates a rock surface. Uncertainties in μ derived from fitting each MET-pIRIR signal depth profile, corresponding the parameter σ φ 0 t ¯ , and calculated ages were too large to allow precise comparisons to be made between vanished and unvarnished rock surfaces. The μ was assumed to be the same for all MET-pIRIR signals, and so was fitted simultaneously to all profiles derived from a single sample; this significantly reduces the fitting uncertainties in the parameters μ and σ φ 0 t ¯ . The long-term relative bleaching rate of the IR 50 , MET-pIRIR 110 , MET-pIRIR 170 and MET-pIRIR 225 signals were evaluated by comparing the ratios of σ φ 0 t ¯ derived from fitting of luminescence-depth profile. The IR 50 signal, MET-pIRIR 110 and MET-pIRIR 170 bleached tens, ∼5, and 2 times faster than the MET-pIRIR 225 signals, respectively. These results highlight the potential and challenges in using rock surface luminescence methods as a viable dating tool for exposure ages.

Landscape evolution in active orogen region is inevitably affected by landslides associated with strong earthquakes, rain or storm. However, quantitative studies of the orogenic or eroded volumes are rarely demonstrated. The 2008 Wenchuan Earthquake triggered serious landsliding, consequently, a large amount of landslide material. However, the landslide volume is estimated mainly on the landslides areas interpreted in their semi-automated landslide mapping algorithm. However, the total volume of landslides triggered by the Wenchuan Earthquake amounts to 5–10 times bigger than the expected upper bound according to the empirical correlation between “total landslide volume” and “moment magnitude”. Here we show that the total landslide volume estimation has large uncertainties to be used to determine whether the Wenchuan Earthquake generates or reduces relief. Thus, the widely held view that large dip-slip and oblique-slip earthquakes build mountainous topography may still be applicable to the Wenchuan Earthquake in Longmen Shan area. To challenge this view, simple landslide volume and co-seismic uplift comparison is not enough, i.e., more data are needed.

Landscape evolution in active orogenic regions is inevitably affected by the repeated strong earthquakes triggered by the corresponding active faults. However, the lack of adequate methods for the documentation and monitoring of mountain-building processes has resulted in a shortage of quantitative estimates of orogenic and eroded volumes. A strong earthquake and its associated co-seismic landslides represent a sudden pulse in landscape evolution in tectonically active areas. The 2008 Mw 7.9 Wenchuan earthquake dramatically modified the topography of the Longmen Shan region. Based on topographic data before the earthquake and stereo pairs of post-earthquake remote sensing imagery, we derived pre- and post-earthquake DEMs (digital elevation models) of the three regions along the Longmen Shan Thrust Belt. By comparing the geomorphic features before and after the earthquake, we find that the Wenchuan earthquake smoothed the steep relief and caused a co-seismic uplift of the Longmen Shan region. The medium-relief regions increased; however, the high-relief regions decreased, indicating that the local relief is controlled by repeated strong earthquakes. The changed slope aspect indicates that the formation and modification of the east- and west-facing slopes are controlled by tectonic events in the Longmen Shan region, which might be associated with the regional stress field. However, the unchanged aspects of other slopes might be controlled by long-term erosion rather than tectonic events. The topographic changes, landslide volume and co-seismic uplift indicate that the greatest seismically induced denudation occurred in association with a thrust faulting mechanism and low-angle fault geometry. Our findings reveal that the local relief has been shaped by the localized, seismically induced high rate of denudation within the plateau margins, and that the formation of local relief is also related to tectonic events, especially the events that have occurred on low-angle faults. This study also indicates that the multi-temporal DEM differential method is valuable in detecting seismically induced topographic change.

The Tianchi Volcano, located on the border between China and North Korea, produced a massive Plinian eruption of Volcanic Explosivity Index (VEI) 7 around 1000 AD, which is referred to as “the Millennium eruption of Tianchi Volcano”. Until now, this volcanic eruption has not been well dated. In this paper, we report a series of new calibrated dates using wiggle-match dating from carbonized logs collected from fallout deposits on the southern and northern flanks of the Tianchi crater. Fifty AMS 14 C ages of tree rings from two logs were obtained for the Hengshan site, south of the Tianchi crater ( Fig. 1 ). These yielded a high-precision wiggle-match date of 921–941 cal AD (95.4%) for the Millennium eruption. Thirty-two AMS 14 C ages of tree rings of other two logs from the Dongfanghong site, north of Tianchi crater ( Fig. 1 ), produced an age range for the volcanic eruption from 921 to 942 cal AD (95.4%). A combined date for the four carbonized logs produced an age of 923–939 cal AD (95.4%) for the Millennium eruption. Moreover, an exact date of late autumn, 938 AD or early spring, 939 AD is suggested based on the impact of the Tianchi Volcano on global climate, especially East Asian climate, and the complete outermost rings of these four trees killed in the eruption.

Regional topographic and geomorphic analyses reveal first-order topographic variations from high-elevation and low-relief interior plateau to the relatively low elevation, high-relief marginal plateau in eastern Tibet. Field investigation and slip distribution modeling after 2008 Ms. 8.0 Wenchuan earthquake indicate significant along-strike variability during the rupture that appears to correspond to different segments of a single fault system. This observation motivates a more careful examination of topographic features along the Longmen Shan to explore the connection between the seismic cycle and mountain building. Analyses of topographic relief, hillslope gradient, and channel gradient indices reveal significant differences in the character of topography along the Longmen Shan mountain front. The central portion of the range exhibits the highest slope, relief and steepness of river longitudinal profiles. Whereas the southern Longmen Shan exhibits only subtle differences associated with slightly lower hillslope and channel gradients, the northern Longmen Shan is characterized by topography of significantly lower relief, lessened hillslope gradients, and low-gradient channels. We consider two explanations for these topographic differences; first, that the differences in topographic development along the Longmen Shan reflect different stages of an evolutionary history. Alternatively, these may reflect differences in the rate of differential rock uplift relative to the stable Sichuan Basin.

In historical records, no earthquake of magnitude comparable with that of the Wenchuan Mw 7.9 earthquake has ever been reported in Chengdu and Longmenshan regions. It is important, therefore, to assess if there is any evidence of prior large earthquakes in the recent geological record. In order to explore this problem, 3 trenches were excavated separately at 3 sites along the surface rupture zones in the middle segment of the Beichuan–Yingxiu Fault and Jiangyou–Guanxian Fault of the Longmenshan fault zone, and the offsets of geomorphic surfaces were measured in the trenches. The basic facts of recurrence of large earthquake on the seismogenic fault of the Wenchuan earthquake are demonstrated in this paper on the basis of the accumulated deformation amounts of old and young geomorphic surfaces as well as the paleoearthquake events revealed in the trenches. The document that at Leigu along the Beichuan–Yingxiu Fault, at Bailu along the Jiangyou–Guanxian Fault, and Xiaoyudong on a NW-trending fault, the height of fault scarp on the second terrace has a multiple relationship to that on the first terrace after the Wenchuan earthquake of 12, May. The elevation difference of the marker horizon (the yellow sandy clay bed) of the second terrace revealed in the trenches on both sides of the fault is nearly twice (or three times larger in Bailu) of that produced by the Wenchuan earthquake. These observations suggest the occurrences of paleoearthquake events with surface deformation comparable to that produced by the Wenchuan Mw 7.9 earthquake. According to the dating data and the fact that there is no such slip of comparable paleoearthquakes in the 2300-year-long historic literature in Longmenshan region, we suggest that the penultimate event occurred between 2300 a BP and 3300 a BP.

The Horqin sand-field in northeastern Inner Mongolia, China, had been the fertile grassland in North China, but desertification and sand-dust storm have increasingly occurred in the past decades [Zhu and Wang, 1992. Theory and practice of sandy desertification in China (in Chinese with English abstract). Quaternary Sciences 2, 97]. To understand the Holocene sand dune activities in this region, five sand dune profiles were investigated, and 32 coarse grain quartz samples were dated by OSL using the single-aliquot regenerative-dose (SAR) protocol [Murray and Wintle, 2000. Luminescence dating of quartz using an improved single-aliquot regenerative-dose protocol. Radiation Measurements 32, 57–73]. For cross-checking, six organic-rich samples from the paleosols and sandy peat/mud were dated by both 14 C and quartz OSL. With one exception, 14 C and quartz OSL dating results show good agreements. Based on the consistent results of five sand dune profiles, a chronology of Holocene dune activity in Horqin sand-field is established as follows: (i) active sand dunes built up widely before 10 ka; (ii) dunes semi-stabilized between 10 and 7.5 ka ago; (iii) the dunes solidify and chernozem soils developed between 7.5 and 2.0 ka ago; and (iv) partially re-mobilization of dunes occurred since about 2.0 ka ago.

The southwestern Chinese Tian Shan of Central Asia is an actively deforming part of the Indian–Asian collision system. Paleomagnetic investigations of two Plio–Pleistocene terrestrial successions provide the first detailed magnetostratigraphy for the upper Cenozoic strata in this region. Paleomagnetic samples were collected from 358 sites within the Atushi Formation and Xiyu Formation across the Atushi–Talanghe anticline near Atushi. Thermal demagnetization behavior, reversal and fold tests of paleomagnetic stability indicate that the characteristic remanence directions were acquired before tilting and folding of the strata. A composite magnetostratigraphic section for this sequence correlates with the Mammoth subchron to the Jaramillo subchron, between 3.3 and 1.07 Myr, of the geomagnetic polarity timescale of Cande and Kent [J. Geophys. Res. 100 (1995) 6093–6095]. The mean declination (349±3°) in the Boguzihe section indicates a counterclockwise vertical-axis rotation (−11±2°) during the past 1.4 Myr. The conglomeratic Xiyu Formation is time-transgressive along its progradational contact with the underlying Atushi Formation across a map distance of ∼6 km; the basal contact ranges from less than 1.0 Myr in the Ganhangou section to 1.9 Myr in the Boguzihe section to the southwest, and to ∼2.8 Myr on the northwest limb of the anticline. Northeastward lateral propagation and growth of the Atushi–Talanghe anticline initiated at ∼1.4 Myr in the Boguzihe, and ∼1.2 Myr in the Ganhangou. The cross section in the Boguzihe provides a conservative (maximum) estimate of shortening rate of ∼3.3 (4.4) mm/yr and uplift rate of ∼3 mm/yr. This rate represents about half of the geodetically determined shortening rate between the northern Tarim Basin and the Kyrgyz Tian Shan [Wang et al., Acta Seismol. Sin. 22 (2000) 263–270; Reiger et al., Earth Planet. Sci. Lett. 191 (2001) 157–165]. During fold growth over the past 1.4 Myr, the crest of the Atushi–Talanghe anticline eroded at an average rate of 2.6–2.7 mm/yr.

Several attempts have been made to directly date phytoliths, but most (14)C results are not consistent with other independent chronologies. Due to the limited dataset, there is not a clear explanation for these discrepancies. Herein, we report the (14)C ages of phytolith-occluded carbon (PhytOC) from contemporary rice and millet crops that were combusted at different temperatures to investigate the relationship between the combustion temperature and resulting (14)C age. Our results show that the (14)C age of PhytOC increases directly with combustion temperature (up to 1100°C) and results in age overestimations of hundreds of years. Considerably older ages are observed at higher temperatures, suggesting that it may be possible to distinguish between two fractions of organic carbon in phytoliths: labile and recalcitrant carbon. These findings challenge the assumption that PhytOC is homogeneous, an assumption made by those who have previously attempted to directly date phytoliths using (14)C.

The detailed14c dating, palynological, carbon isotope and magnetic susceptibility analyses of a paleo-swamp record obtained near Beijing show that the succession of climate events in Beljing area is broadly consistent with the climatic behavior in the North Atlantic region during the period from 13 000 to 10 000 a B. P., but with evident local characteristics. A relatively warm and wet episode (11 400-10 950 a B.P.) was intercalated between two dry-cold episodes (11 600-11 400 and 10 950-10 450 a B. P.).

Hillslope instability has been thought to be one of the most important factors for landslide susceptibility. In this study, we apply geomorphic analysis using multi-temporal DEM data and shake intensity analysis to evaluate the topographic characteristics of the landslide areas. There are many geomorphologic analysis methods such as roughness, slope aspect, which are also as useful as slope analysis. The analyses indicate that most of the co-seismic landslides occurred in regions with roughness, hillslope and slope aspect of >1.2, >30, and between 90 and 270, respectively. However, the intersection regions from the above three methods are more accurate than that derived by applying single topographic analysis method. The ground motion data indicates that the co-seismic landslides mainly occurred on the hanging wall side of Longmen Shan Thrust Belt within the up-down and horizontal peak ground acceleration (PGA) contour of 150 PGA and 200 gal, respectively. The comparisons of pre- and post-earthquake DEM data indicate that the medium roughness and slope increased, the roughest and steepest regions decreased after the Wenchuan earthquake. However, slope aspects did not even change. Our results indicate that co-seismic landslides mainly occurred at specific regions of high roughness, southward and steep sloping areas under strong ground motion. Co-seismic landslides significantly modified the local topography, especially the hillslope and roughness. The roughest relief and steepest slope are significantly smoothed; however, the medium relief and slope become rougher and steeper, respectively. Electronic supplementary material The online version of this article (doi:10.1186/2193-1801-2-544) contains supplementary material, which is available to authorized users.

We used airborne light detection and ranging (LiDAR) data to reevaluate the single-event offsets of the 1920 Haiyuan Ms 8.5 earthquake and the cumulative offsets along the western and middle segments of the coseismic surface rupture zone. Our LiDAR data indicate that the offset observations along both the western and middle segments fall into groups. The group with the minimum slip amount is associated with the 1920 Haiyuan Ms 8.5 earthquake, which ruptured both the western and middle segments. Our research highlights two new interpretations: First, the previously reported maximum displacement of the 1920 earthquake was likely due to at least two earthquakes; second, our results reveal that the cumulative offset probability density (COPD) peaks of the same offset amounts on the western and middle segments do not correspond to one another one-to-one. We suggest that any discussion of the rupture pattern of a certain fault based on the offset data should also consider fault segmentation and paleoseismological data. Therefore, the COPD peaks should be computed and analyzed on fault subsections and not entire fault zones to study the number of paleoearthquakes and their rupture patterns.

The field investigations of geomorphology and Quaternary sediment sequences show that the sediment stratigraphic profile containing the skull of the Homo sapiens Daliensis (Dali Man) at Tianshuigou trench, Jiefang Village (109° 44′E, 34°52′N), Dali County, Shaanxi Province, is composed of the loess-paleosol sequence, 17.3 m thick, in the upper part, and the alluvial silts, fine sands and sandy gravels interbedded, 15.4 m thick, in the lower part. There are the well developed layers L1, S1, L2 and S2 in the loess-paleosol sequence of the profile, which are comparable; to those of the Luochuan loess section on the basis of magnetic succeptibility measurements and IRSL dating of the loess samples. An alluvial gravel layer, where the skull of the Dali Man was discovered, is in 13 m beneath the bottom of paleosol S2, implying that, the age of the Dali Man must be older than about 247 kaBP when the paleosol S2 began to be developed. The samples of mammal animal tooth and shell fossils from the gravel layer containing the skull of the Dali Man have been dated by uranium series and ESR methods respectively. Based on the multiple dating results and the stratigraphic chronology, the age of the Dali Man, therefore, would be estimated as older than 250 kaBP and younger than 350 kaBP, and reasonably estimated as 260–300 kaBP.