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Time series prediction refers to the learning of existing observed data of a parameter and predicting its future evolution. Based on the application of machine/deep learning methods in the field of engineering geology, it is desirable to predict the time series evolution of microseismic parameters in the process of rockburst development. Our study explores key microseismic indices that help describe the development process of rockbursts based on abundant rockburst data obtained from deep underground engineering construction. The integrated process of dynamic moving-window method and improved convolutional neural network (CNN) realizes the evolution prediction of multiple microseismic parameters or their different combinations, and the modified model structures of a univariate, multivariate input and a single-step, multi-step output are established. Various models of the multiple microseismic parameters for the CNN-based time series prediction are innovated, including a univariate prediction model, a multiple parallel series model, a multiple input series model, and a multivariate multi-step prediction model. Model training, testing, and interpretation of the rockburst risk and comparative analyses of the different models are performed for the complete process of multiple rockbursts. The results show that the proposed models can well predict the evolution trends in the various key characteristics during rockbursts. The predicted trend of multiple microseismic parameters provides time labels for rockburst prediction and risk judgement, which is conducive to rockburst early warning. This study provides a new research idea for the prediction and early warning of rockbursts in the field of deep underground and mining engineering.

The closely spaced tunnels structure has been widely used in traffic tunnels, hydropower stations, collieries and underground metal mines. Blasting has important implications for the construction of these closely spaced tunnels. Due to the effect of multi-free surfaces and the appearance of excavation damaged zones (EDZs), the propagation and attenuation of blast vibration are expected to be more complex than in ordinary separated tunnels. In this study, field tests including ultrasonic tests and vibration tests were conducted during the excavation process of a closely spaced tunnels project, then a series of three-dimensional dynamic calculations considering explosive velocity detonation were conducted to study the propagation and attenuation of blast vibration. The results indicate that in closely spaced tunnels, EDZs have evident amplification effects on the vibration intensity, especially on the Rayleigh waves propagating longitudinally. The small clear distance and larger dimensionless wavenumber lead to the asymmetric distribution of vibration velocity, and the side wall located in the wave incident side is more easily damaged. In tunnel blasting, the maximum Peak Particle Velocity often appears around the heading face, while the maximum value appears at 1.5–3.0 m behind the heading face section for adjacent tunnels. The results of this study can be applied in the design of blasting and monitoring scheme of closely spaced tunnels.

The westward transversal current (TC) in the southern Yellow Sea entrance was investigated during winter 2007 using a numerical ocean model. The three-dimensional structures and dynamics of the westward TC were highlighted. The model-simulated monthly mean current fields showed that the strong westward TC was limited to the upper water column (shallower than 50 m) and extended westward from 126° E to 124° E. Momentum balance analysis indicated that the westward TC was mainly regulated by a quasi-geostrophic balance. Both the sea surface elevation–related barotropic pressure gradient force and the density-related baroclinic pressure gradient force controlled the intensity and direction of the westward TC. Sensitivity model experiments focusing on tide and wind demonstrated that the westward TC was intensified when tide was ignored and was greatly weakened when wind was excluded. Lagrangian particle tracking experiments were also performed, to investigate the relationship between the Yellow Sea Warm Current and the westward TC in the frontal region. The characteristics of the water in the Yellow Sea Warm Current were affected by the properties of the water in the frontal zone, especially in the sub-surface and lower layers. The westward TC might act as an important bridge, connecting the frontal zone with the Yellow Sea Warm Current flowing along the western Yellow Sea trough.

The vertical mixing parameterization scheme, by providing the effects of some explicitly missed physical processes and more importantly closing the energy budgets, is a critical model component and therefore imposes significant impacts on model performance. The Yellow Sea Cold Water Mass (YSCWM), as the most striking and unique phenomenon in the Yellow Sea during summer, is dramatically affected by vertical mixing process during its each stage and therefore seriously sensitive to the proper choice of parameterization scheme. In this paper, a hindcast of YSCWM in winter of 2006 was implemented by using the Regional Ocean Modeling System (ROMS). Three popular parameterization schemes, including the level 2.5 Mellor-Yamada closure (M-Y 2.5), Generic Length Scale closure (GLS) and K-Profile Parameterization (KPP), were tested and compared with each other by conducting a series of sensitivity model experiments. The influence of different parameterization schemes on modeling the YSCWM was then carefully examined and assessed based on these model experiments. Although reasonable thermal structure and its seasonal variation were well reproduced by all schemes, considerable differences could still be found among all experiments. A warmer and spatially smaller simulation of YSCWM, with very strong thermocline, appeared in M-Y 2.5 experiment, while a spatially larger YSCWM with shallow mixed layer was found in GLS and KPP schemes. Among all the experiments, the discrepancy, indicated by core temperature, appeared since spring, and grew gradually by the end of November. Additional experiments also confirmed that the increase of background diffusivity could effectively weaken the YSCWM, in either strength or coverage. Surface wave, another contributor in upper layer, was found responsible for the shrinkage of YSCWM coverage. The treatment of wave effect as an additional turbulence production term in prognostic equation was shown to be more superior to the strategy of directly increasing diffusivity for a coastal region.

The role of tumor-infiltrating lymphocytes (TILs) in the immune remodeling of tumor microenvironments (TME) in oral squamous cell carcinoma (OSCC) remains controversial. In this study, we pursued a comprehensive characterization of the repertoire of TILs and then analyzed its clinical significance and potential prognostic value. Fresh tumor tissue samples and peripheral blood from 83 OSCC patients were collected to comprehensively characterize the phenotypes and frequencies of TILs by flow cytometry. Archived paraffin-embedded tissues derived from 159 OSCC patients were analyzed by immunohistochemistry to further assess the TIL repertoire. The clinical significance of TILs and their potential prognostic value were further analyzed. A series of unique features of TILs were observed. IL-17 was highly expressed in betel nut chewers, and CD20 was abundantly expressed in patients who did not drink alcohol; high expression of CD138, PD-L1, and Foxp3 was associated with poor prognosis. The Th17/Treg ratio was an independent prognostic factor for patient survival with greater predictive accuracy for overall survival. Our results suggest an antigen-driven immune response; however, the immune dysfunction within the microenvironment in OSCC and the Th17/Treg balance may play important roles in the modulation of antitumor immunity.

Based on the data from a special project titled China’s Offshore Marine Integrated Investigation and Evaluation as well as Regional Ocean Modeling Systems (ROMS) diagnostic numerical model, we studied the influence of high wind processes on the circulation and water exchange between the Bohai and Yellow Seas (BYS) in winter. The results show that the vertical structure of the Yellow Sea Warm Current (YSWC) is relatively uniform under condition of high winds, showing obvious barotropic features. However, this flow is not a stable mean flow, showing strong paroxysmal and reciprocating characteristics. A comparison of the changes in sea level suggests that the intensity of the northwards upwind flow is consistent with the abnormal fluctuations in the sea level. It indicates that the upwind flow is closely related to the water exchange between the BYS. The impact of high wind processes on the water exchange between the BYS is enormous. It can make the flux through the Bohai Strait, as well as that through the mouth of each constituent bay (i.e., Liaodong Bay, Bohai Bay, and Laizhou Bay) far greater than usual, resulting in a significant increase in the water exchange rate. The exchange capacity, which is about 8% of the total volume of the Bohai Sea, can be completed in a few days. Therefore, the water exchange of the Bohai Sea may be completed by only a few occasional high wind processes in winter.

The bit-bounce is detrimental to the service life of drillstring and bit. This study highlights the influence of axial excitation and torsional excitation on the bit-bounce in horizontal well. Because of the complicated surroundings of downhole, Hamilton principle, a kind of energy method, is employed in this paper to derive the motion equation of the drillstring, which is discreted through finite element method. The impact–friction between the drillstring and borehole wall, and bit–rock and fluid–structure interaction are also modeled in this paper. The research results show that both axial excitation and torsional excitation greatly affect the dynamic behavior of the drillstring. Both the amplitude and the intensity of bit-bounce reduce with the development of the axial excitation and torsional excitation. And the test results are in agreement with the numerical simulation. The results of both have been mutually verified.

A coupled approach based on grain size and geochemical elements is used to trace the provenance of surface sediments and to confirm the distribution patterns of grain size and elements on the continental shelf off western Guangdong Province and northeastern Hainan Island. The mean grain size ranges from 0.05 ϕ to 7.28 ϕ with a mean value of 5.60 ϕ. The average concentrations of major elements descend in the order of SiO2 >Al2O3 >CaO>Fe2O3 >K2O>MgO>Na2O>TiO2 >P2O5 >MnO, while those of trace elements exhibit a descending order of Sr>Rb >Zn>V>Cr>Pb>Ni>Cu>As>Cd. On the basis of the distribution patterns of elements and results of statistical analysis, the study area is classified into three zones. Zone I locates on the continental shelf off western Guangdong Province, and the sediments are mainly from Pearl River, Taiwanese rivers, and small rivers nearby. Zone II locates in the eastern exit of Qiongzhou Strait and the coastal area off Leizhou Peninsula, and the sediments are mainly from the erosion products of Qiongzhou Strait and Hainan Island. Zone III locates off the eastern Hainan Island and the continental shelf deeper than −50 m isobaths, and the sediments are mainly from Hainan Island and coral reef. The influence from open water should also be considered. Results indicate that the grain size is the main controlling factor for major and trace element contents and that anthropogenic impact and biological activity also play an important role in the distribution of these elements.

Three winter storms struck the Bohai and Yellow seas in succession during February 16–25, 2017. Periodic fluctuations of sea level, currents, temperature, and salinity were recorded at a moored station deployed in the Bohai Strait. Observations also captured significant synoptic fluctuations of inflow and outflow through the Bohai Strait with maximum magnitude exceeding 50 cm s−1. The sea level dropped by > 1 m and the bottom temperature decreased by 2.5 °C in

Repair, reconstruction, and replacement of congenital malformations, either in case of exogenous or iatrogenic tissue and organ defects, requires utilization of a large number of personalized biomaterials. In recent decades, the improvement of people’s quality of life and the prolongation of life expectancy have promoted the development of medical and material science. In addition to the traditionally used stainless steel, other materials such as cobalt–chromium alloy, pure titanium, titanium alloy, and the newly alloy materials continue to emerge, such as tantalum-based alloy materials which have been used in clinic, especially the application of porous tantalum trabecular metal in orthopedics. This paper which has provided good preliminary works for the development of tantalum biomaterials with more advantages in the future such as tantalum dental implants summarizes in detail the progress of tantalum materials in physicochemical properties and biocompatibility in recent years. From the comparison of surface passivation films of different metals in different environments, the electrochemical corrosion behavior of tantalum, the release of different metal ions and the damage to cells, it is concluded that tantalum has excellent corrosion resistance. Besides, the excellent biocompatibility of tantalum metals concluded by cytology, molecular biology, protein adsorption experiment, and hematology experiment, as well as regular follow-up observation of patients with porous tantalum trabecular metal in clinic. The excellent corrosion resistance and biocompatibility of the tantalum metal have a very wide prospect in clinical application.

We study Hermite–Fejer interpolation operators in spaces of weighted maximum norm, whose nodes are the zeros of Jacobi polynomials with indexes $$\alpha , \beta >-1$$. The approximation behaviour of those operators is presented by the so-called strong inequalities. Moreover, such strong inequalities are valid for any individual continuous function on $$[-1, 1]$$. The obtained result covers also the saturation of these operators.

The Finite Volume Community Ocean Model (FVCOM) was adapted to the Northern South China Sea (NSCS) to investigate the seasonality of coastal circulation, as well as along-shelf and cross-shelf transport. In fall and winter, southwestward current dominates the NSCS shelf, while the current’s direction shifts to northeast in summer. The circulation pattern in spring is more complicated: both southwestward and northeastward currents are detected on the NSCS shelf. The mean shelf circulation pattern in winter does not show the permanent counter-wind South China Sea Warm Current (SCSWC) along the 100–200 m isobaths. Meanwhile, the model results indicate a northeastward current flowing along 50–100 m isobaths in spring. Southwestward along-shelf transport varies from 0.30–1.93 Sv in fall and winter, and it redirects to northeast in summer ranging from 0.44–1.09 Sv. Onshore transport is mainly through the shelf break segment southeast of the Pearl River Estuary.

Underground mining leads to deformation of the surrounding rock strata. Over time, this deformation tends to stabilize after mining has completed. However, ground movement can easily reactivated if another adjacent underground project is excavated nearby. When tunnelling underneath caved mining areas, the associated effects on load distribution and liner behavior of this caved zone can be significant. This paper presents a series of scale model tests to understand these effects. In these tests, various testing material compositions were used to simulate intact rocks, a caved zone, primary support and secondary liner based on similarity theory. Various caved zone-tunnel distances (d) and different buried depths were considered in the tests. Results such as deformation, thrust force and bending moment of the liner were recorded and compared. The results show that the caved zone has an obvious impact on the liner when it is located above and nearby the tunnel, but this influence decreases rapidly as a function of d. If the caved zone-tunnel distance is between 50% and 100% of the tunnel span, the bearing capability of the rock immediately surrounding the excavation is significantly reduced, which leads to more vertical load on the support of the tunnel compared to a tunnel without a caved zone. Furthermore, as the shape of broken rock is irregular and the arrangement is random, the caved zone creates an asymmetrical distribution of displacements if the tunnel is near the caved zone. Additionally, this may result in large moments and damage at the tunnel crown.

This paper extends Archimedean t-norm and t-conorm to aggregate the dual hesitant fuzzy linguistic information. Firstly, some basic concepts of dual hesitant fuzzy linguistic elements (DHFLEs) and operational rules of Archimedean t-norm and t-conorm are introduced. Secondly, some general operators about the DHFLEs are developed based on Archimedean t-norm and t-conorm, such as the Archimedean t-norm- and t-conorm-based dual hesitant fuzzy linguistic weighted averaging operator, Archimedean t-norm- and t-conorm-based dual hesitant fuzzy linguistic weighted geometric operator, Archimedean t-norm- and t-conorm-based generalized dual hesitant fuzzy linguistic weighted averaging operator, Archimedean t-norm- and t-conorm-based generalized dual hesitant fuzzy weighted geometric operator, which operates without loss of information, and some desirable properties of those new operators are studied in detail. Furthermore, an approach based on the proposed operators under dual hesitant fuzzy linguistic decision-making problem is presented. Finally, an example is used to show the practical advantages of the proposed method and a sensitivity analysis of the decision results is also showed as the parameter changes.

Neuropathic pain is a complicated clinical syndrome caused by heterogeneous etiology. Despite the fact that the underlying mechanisms remain elusive, it is well accepted that neuroinflammation plays a critical role in the development of neuropathic pain. Fascin-1, an actin-bundling protein, has been proved to be involved in the processing of diverse biological events including cellular development, immunity, and tumor invasion etc. Recent studies have shown that Fascin-1 participates in antigen presentation and the regulation of pro-inflammatory agents. However, whether Fascin-1 is involved in neuropathic pain has not been reported. In the present study we examined the potential role of Fascin-1 by using a rodent model of chronic constriction injury (CCI). Our results showed that Fascin-1 increased rapidly in dorsal root ganglions (DRG) and spinal cord (SC) after CCI. The increased Fascin-1 widely expressed in DRG, however, it localized predominantly in microglia, seldom in neuron, and hardly in astrocyte in the SC. Intrathecal injection of Fascin-1 siRNA not only suppressed the activation of microglia and the release of pro-inflammatory mediators, but also attenuated the mechanical allodynia and thermal hyperalgesia induced by CCI.

The relationship between the East Asian winter monsoon (EAWM) and East Asian summer monsoon (EASM) during the Holocene is complicated and remains controversial. In this study, analysis of grain size and benthic foraminiferal oxygen isotope, as well as accelerator mass spectrometry 14C dating was performed on a sediment core retrieved from the newly revealed muddy deposit on the northern South China Sea continental shelf. The history of the EAWM and EASM were reconstructed for the last 8200 a BP. Further analysis in conjunction with previously published paleo-climate proxies revealed that the relationship between the EAWM and EASM during the Holocene is more complex than a simple and strict anti-phase one-both negative and positive correlations were identified. The EAWM and EASM are negatively correlated around 7500, 4800, 4200, 3200, and 300 a BP (cooling periods), while positively correlated around 7100, 3700, and 2100 a BP (warm periods). In particular, both the EAWM and EASM intensified during the three positive correlation periods. However, we also found that the relationship between these two sub-monsoons is anti-phase during the final phase of particularly hot periods like Holocene Optimum and Medieval warm period. The possible impact from variations of solar irradiance on the relationship between the EAWM and EASM was also discussed.

The characteristics and dynamical mechanism of summer-time coastal current over the North South China Sea shelf have been investigated based on a high resolution unstructuredgrid finite volume community ocean model (FVCOM). Modeldata comparison demonstrates that the model describes and explains well the coastal dynamics over the North South China Sea shelf. The coastal current on the North South China Sea shelf is greatly influenced by monsoon and the freshwater discharge of the Pearl River. Strong southwesterly wind drives the coastal current northeastward. However, under weak southwest monsoon, the coastal current west of the Pearl River estuary (PRE) advects toward the southwest, and splits into two parts when reaching east of the Qiongzhou Strait, with one branch entering the Gulf of Tonkin through the Qiongzhou Strait, transporting low salinity water into the Gulf of Tonkin, and the other part flows cyclonic and interacts with the northeastward current around southeast of Hainan Island, forming a cyclonic eddy east of the Qiongzhou Strait. A variety of model experiments focused on freshwater discharge, wind forcing, tidal rectification, and stratification are performed to study the physical mechanism of the southwestward coastal current which is usually against the summer wind. Process-oriented experiment results indicate that the southwest monsoon and freshwater discharge are important factors influencing the formation of southwestward coastal current during summer.

Ground volume loss induced by shield tunnel construction is the major factor leading to ground settlement and deformation. The general equations predicting surface settlement based on ground volume loss involve a settlement trough width coefficient (parameter i) which in previous models was set as a constant in both the transverse and longitudinal directions. In this work, the equations predicting surface settlement during the construction were modified by introducing the parameter j – the width coefficient in the longitudinal direction, assumed to be different from that in the transverse direction. A model shield machine was adopted to carry a laboratory test under 1 g to investigate surface settlement induced by earth-pressure-balance shield tunnel construction in unsaturated sandy soil. The surface settlement during the excavating observed in the test was compared with that predicted by general equations from previous studies and the modified. The results showed that surface settlement above shield machine obtained by the modified equation proposed here fits the test data better than those obtained by the general equations because of the introduced longitudinal width coefficient.

A multivariate statistical downscaling method is developed to produce regional, high-resolution, coastal surface wind fields based on the IPCC global model predictions for the U.S. east coastal ocean, the Gulf of Mexico (GOM), and the Caribbean Sea. The statistical relationship is built upon linear regressions between the empirical orthogonal function (EOF) spaces of a cross- calibrated, multi-platform, multi-instrument ocean surface wind velocity dataset (predictand) and the global NCEP wind reanalysis (predictor) over a 10 year period from 2000 to 2009. The statistical relationship is validated before applications and its effectiveness is confirmed by the good agreement between downscaled wind fields based on the NCEP reanalysis and in-situ surface wind measured at 16 National Data Buoy Center (NDBC) buoys in the U.S. east coastal ocean and the GOM during 1992–1999. The predictand-predictor relationship is applied to IPCC GFDL model output (2.0°×2.5°) of downscaled coastal wind at 0.25°×0.25° resolution. The temporal and spatial variability of future predicted wind speeds and wind energy potential over the study region are further quantified. It is shown that wind speed and power would significantly be reduced in the high CO2 climate scenario offshore of the mid-Atlantic and northeast U.S., with the speed falling to one quarter of its original value.

It is nontrivial to extract the dust top height (DTH) accurately from passive instruments over land due to the complexity of the surface conditions. The Moderate Resolution Imaging Spectroradiometer (MODIS) deep blue (DB) algorithm can be used to infer the aerosol optical depth (AOD) over high-reflective surfaces. The Atmospheric Infrared Sounder (AIRS) can simultaneously obtain the DTH and optical depth information. This study focuses on the synergistic use of AIRS observations and MODIS DB results for improving the DTH by using a stable relationship between the AIRS infrared and MODIS DB AODs. A one-dimensional variational (1DVAR) algorithm is applied to extract the DTH from AIRS. Simulation experiments indicate that when the uncertainty of the dust optical depth decreases from 50% to 20%, the improvement of the DTH retrieval accuracy from AIRS reaches 200 m for most of the assumed dust conditions. For two cases over the Taklimakan Desert, the results are compared against Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) measurements. The results confirm that the MODIS DB product could help extract the DTH over land from AIRS.

Cloud microphysical property retrievals from the active microwave instrument on a satellite require the cloud droplet size distribution obtained from aircraft observations as a priori data in the iteration procedure. The cloud lognormal size distributions derived from 12 flights over Beijing, China, in 2008–09 were characterized to evaluate and improve regional CloudSat cloud water content retrievals. We present the distribution parameters of stratiform cloud droplet (diameter

X-ray diffraction analysis of black shale of Upper Triassic Member Chang 7 of the Yanchang Formation in southeastern Ordos Basin showed that black shales were deposited in brackish, strongly reducing, semi-deep-deep lacustrine facies, and mainly composed of quartz, feldspar, carbonate (dolomite), clay minerals (illite and il- lite/smectite) and a certain amount of pyrite. The mineral composition characteristics of this set of black shales are similar to those of highly productive shale gas in North America, for example shallow burial, low clay mineral and abundant brittle mineral, so the strata are conducive to the development of cracks and fractures. Thus, this area is favorable for shale oil/gas exploration and development.

A clean, efficient method to synthesize 2-amino-4H-3,1-benzothiazines by ytterbium chloride-catalyzed tandem addition-cyclization reaction of o-aminocinnamate and isothiocyanates under solvent-free conditions is developed.

The mid-wave infrared band (3–5 µm) has been widely used for atmospheric soundings. The sunglint impact on the atmospheric parameter retrieval using this band has been neglected because the reflected radiances in this band are significantly less than those in the visible band. In this study, an investigation of sunglint impact on the atmospheric soundings was conducted with Atmospheric InfraRed Sounder observation data from 1 July to 7 July 2007 over the Atlantic Ocean. The impact of sunglint can lead to a brightness temperature increase of 1.0 K for the surface sensitive sounding channels near 4.58 µm. This contamination can indirectly cause a positive bias of 4 g kg−1 in the water vapor retrieval near the ocean surface, and it can be corrected by simply excluding those contaminated channels.

A high-resolution hybrid data assimilative (DA) modeling system is adapted to study the M2 barotropic tidal characteristics and dynamics in the Bohai and Yellow Seas. In situ data include tidal harmonics extracted from both coastal sea level and bottom pressure observations. The hybrid DA system consists of both forward and inverse models. The former is three-dimensional, finite-difference, nonlinear Regional Ocean Modeling System (ROMS). The latter is a three-dimensional, linearized, frequency-domain, finite-element model TRUXTON. The DA system assimilates in situ observations via the inversion of the barotropic tidal open boundary conditions (OBCs). Model skill is evaluated by comparing misfits between the observed and modeled tidal harmonics. The assimilation scheme is found effective and efficient in correcting the tidal OBCs, which in turn improves ROMS tidal solutions. Up to 50% reduction of model/data misfits is achieved after data assimilation. M2 co-tidal maps constructed from the posterior (data assimilative) ROMS solutions agree well with observational analysis of (Fang et al. 2004). Detailed analyses on tidal mixing, residual current, energy flux, dissipation, and momentum term balance dynamics are performed for M2 constituent, revealing complex M2 tidal characteristics in the study region and the important role of coastal geometry and topography in affecting regional tidal dynamics.

Analysis of tidal current and sea level has been made based on the observations from the summer of 2006 to the winter of 2007, respectively. The result indicates that a two-layer structure of residual current exists in summer, with its upper layer going northwestward and the lower layer southeastward. In addition, some strong residuals exist in the neighboring depth of the pycnocline during the current period of astronomical tide. In winter, except some individual layersthe residual currents mostly direct to the northwest, from which we can see the fluctuation of abnormal sea-level and the appearance of associated current because of the changes of the wind field. The analysis of tidal ellipse indicates that the direction of the maximum semidiurnal component is clockwise from summer to winter, with an angle of 16°–18°. Moreover, in summer the semidiurnal component rotates with depth clockwise while the diurnal component counterclockwise. However, the vertical structure is almost homogeneous in winter.

The multi-pulse orbits and chaotic dynamics of a simply supported laminated composite piezoelectric rectangular plate under combined parametric excitation and transverse excitation are studied in detail. It is assumed that different layers are perfectly bonded to each other with piezoelectric actuator patches embedded. The nonlinear equations of motion for the laminated composite piezoelectric rectangular plate are derived from von Karman-type equation and third-order shear deformation plate theory of Reddy. The two-degree-of-freedom dimensionless equations of motion are obtained by using the Galerkin approach to the partial differential governing equation of motion for the laminated composite piezoelectric rectangular plate. The four-dimensional averaged equation in the case of primary parametric resonance and 1:3 internal resonances is obtained by using the method of multiple scales. From the averaged equation, the theory of normal form is used to find the explicit formulas of normal form. Based on the normal form obtained, the energy phase method is utilized to analyze the multi-pulse global bifurcations and chaotic dynamics for the laminated composite piezoelectric rectangular plate. The analysis of the global dynamics indicates that there exist multi-pulse jumping orbits in the perturbed phase space of the averaged equation. Based on the averaged equation obtained, the chaotic motions and the Shilnikov type multi-pulse orbits of the laminated composite piezoelectric rectangular plate are also found by numerical simulation. The results obtained above mean the existence of the chaos in the Smale horseshoe sense for the simply supported laminated composite piezoelectric rectangular plate.

For understanding more about the water exchange between the Kuroshio and the East China Sea, We studied the variability of the Kuroshio in the East China Sea (ECS) in the period of 1991 to 2008 using a three-dimensional circulation model, and calculated Kuroshio onshore volume transport in the ECS at the minimum of 0.48 Sv (1 Sv ≡ 106 m3/s) in summer and the maximum of 1.69 Sv in winter. Based on the data of WOA05 and NCEP, The modeled result indicates that the Kuroshio transport east of Taiwan Island decreased since 2000. Lateral movements tended to be stronger at two ends of the Kuroshio in the ECS than that of the middle segment. In addition, we applied a spectral mixture model (SMM) to determine the exchange zone between the Kuroshio and the shelf water of the ECS. The result reveals a significantly negative correlation (coefficient of −0.78) between the area of exchange zone and the Kuroshio onshore transport at 200 m isobath in the ECS. This conclusion brings a new view for the water exchange between the Kuroshio and the East China Sea. Additional to annual and semi-annual signals, intra-seasonal signal of probably the Pacific origin may trigger the events of Kuroshio intrusion and exchange in the ECS.

The analysis on the chaotic dynamics of a six-dimensional nonlinear system which represents the averaged equation of a composite laminated piezoelectric rectangular plate is given for the first time. The theory of normal form and the energy-phase method are combined to investigate the higher-dimensional chaotic dynamics of the composite laminated piezoelectric rectangular plate. Firstly, the theory of normal form is used to reduce the six-dimensional averaged equation to the simpler normal form. Then, the energy-phase method is extended to analyze the global bifurcations and chaotic dynamics of a six-dimensional nonlinear system. The analysis results indicate that there exist the homoclinic bifurcation and Shilnikov type multi-pulse chaos for the composite laminated piezoelectric rectangular plate. Finally, numerical simulations are also used to investigate the nonlinear dynamic characteristics of the composite laminated piezoelectric rectangular plate. The results of numerical simulations also demonstrate that there exist the chaotic motions and the multi-pulse jumping orbits of the composite laminated piezoelectric rectangular plate.

The bifurcations and chaotic dynamics of a simply supported symmetric cross-ply composite laminated piezoelectric rectangular plate are studied for the first time, which are simultaneously forced by the transverse, in-plane excitations and the excitation loaded by piezoelectric layers. Based on the Reddy’s third-order shear deformation plate theory, the nonlinear governing equations of motion for the composite laminated piezoelectric rectangular plate are derived by using the Hamilton’s principle. The Galerkin’s approach is used to discretize partial differential governing equations to a two-degreeof-freedom nonlinear system under combined the parametric and external excitations. The method of multiple scales is employed to obtain the four-dimensional averaged equation. Numerical method is utilized to find the periodic and chaotic responses of the composite laminated piezoelectric rectangular plate. The numerical results indicate the existence of the periodic and chaotic responses in the averaged equation. The influence of the transverse, in-plane and piezoelectric excitations on the bifurcations and chaotic behaviors of the composite laminated piezoelectric rectangular plate is investigated numerically.

The Dongting Lake, the second biggest freshwater lake in China, consists of three wetlands of national importance, namely the East Dongting Lake, the South Dongting Lake, and the West Dongting Lake. Surface sediments were sampled from 57 locations across the lake. Nutrient concentrations [total organic carbon (TOC), total N (TN) and total P (TP)] and 16 element concentrations (Al, As, B, Ca, Cd, Cr, Cu, K, Fe, Hg, Mn, Ni, Pb, Si, Ti and Zn) in the sediments were measured to investigate the impact of industrialization along the lake’s coastline and several tributaries on the profiles of nutrients and heavy metals in the lake’s surface sediments. R-mode cluster analysis (CA) was used to integrate geochemical data. The result showed that euthophication of the Dongting Lake resulted mainly from TN and TOC. The main polluting trace metals are Hg, As, Cd, Zn, Pb and Mn, which are largely adsorbed on clay minerals or Fe/Mn oxides, or deposited as carbonates. Principal component analysis (PCA) revealed the source of micropollutants. The worst affected district by heavy metals is the East Dongting Lake, the pollution sources may originate mainly from the Xiangjiang drainage area. The results demonstrated that multivariate methods are the potentially great tools for the interpretation of the environmental data on lake sediments.

The form in which a metal exists strongly influences its mobility and thus, the effects on the environment. Operational methods of speciation analysis, such as the use of sequential extraction procedures, are commonly applied. The Dongting Lake, the second largest fresh-water lake in China, contains three China wetlands of international importance, the East Dongting Lake, South Dongting Lake, and West Dongting Lake. In this work, an optimized BCR sequential extraction procedure was used to assess the environmental risk of Cd, Cr, Cu, Ni, Pb and Zn in contaminated sediment of the Dongting Lake. The procedure was evaluated by using a certified reference material, BCR701. The results of the partitioning study indicated that in the lake sediments, more easily mobilized forms (acid exchangeable) were predominant for Cd, particularly in the samples from the East Dongting Lake. In contrast, the largest amount of Pb was associated with the iron and manganese oxide fractions and Cu, Zn, Cr, and Ni analyzed were mainly distributed in residual phase at an average percentage greater than 60% of the total metals. The potential risk to the lake’s water contamination was highest in the East Dongting Lake based on the calculated contamination factors. On the other hand, the total metal content was determined as well by inductively coupled plasma and mass spectrometry (ICP-MS) and assessed by using geo-accumulation index. The assessment results using geo-accumulation index were compared with the information on metal speciation. Both were correspondent with each other.

Heavy metals are released into environment from a wide range of natural and anthropogenic sources. Aquatic ecosystems are normally at the receiving end and in many cases, with lakes as intermediaries. Lacustrine sediments are important sinks for heavy metals and play a significant role in enrichment and remobilization of heavy metals in aquatic systems. Therefore, characteristics of heavy metal in lacustrine sediments become one of the important issues in environmental sciences. Progress in heavy metal research of lake sediments since late 1980s is reviewed comprehensively in this paper from over 100. The Highlights are placed on the establishment of aquatic sediment quality guidelines, references chemical speciation of heavy metals, heavy metal transport mechanisms in lakes, and high-resolution study of lake borehole cores. Meanwhile, suggestions for heavy metal research in lacustrine sediment in the future are proposed, including such issues as using integrated approaches to assess aquatic ecosystem, modern lake dynamic process, high-resolution evolutionary sequence and spatial differentiation of environments and international lake database, which should be referential to the promotion of research on heavy metal in aquatic system.

water to this reservoir, and within the two reservoirs. Those isotopic measurements indicate the rapid change of natural sources of nitrate to one indicative of anthropogenic influences from inputs of animal manure and septic waste. Although the isotopic measurements suggest that animal and septic wastes are a primary source of nutrients, measurements of the ratio of nitrogen to phosphorus are more indicative of row cropping practices. Options for reduction of nutrient loads included changing the management practices of the aqua culture, installation of new sewage treatment systems, especially in the one major urbanized area of the upper watershed, and agricultural man.