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Suspended sediment concentration (SSC) time series are highly nonlinear and nonstationary due to numerous influencing factors that can be characterized by specific time scales, thereby increasing the difficulty of performing SSC simulations. Analyzing the spectral and temporal information of the SSC and its contributing factors can improve the resulting simulation efforts. In this study, the Hilbert-Huang transform (HHT) was used to identify the time scales and change trends of the daily SSC, rainfall, runoff and normalized difference vegetation index (NDVI) of the Kuye River in the Loess Plateau of China. Artificial neural network (ANN), multiple linear regression (MLR), hybrid ensemble empirical mode decomposition (EEMD)-ANN and EEMD-MLR models were chosen to simulate the SSC time series. The periods of the rainfall intrinsic mode functions (IMFs, except IMF9 and 10) were generally consistent with those of the IMFs corresponding to the SSC and runoff. In comparison, the periods of the IMFs corresponding to the NDVI were longer. The minimal period was 3 days for the SSC, rainfall and runoff and 10 days for the NDVI. The minimal period displays the greatest variance contribution and plays the most important role in the SSC, rainfall and runoff changes. The annual cycle has the largest contribution to the NDVI variability. Residual components indicated that the SSC of the Kuye River decreased from 2006 to 2010, while the regional rainfall, runoff and NDVI increased. The R2 values of the ANN and MLR models were 0.34 and 0.39, respectively. Compared with the MLR and ANN models, the R2 values of the EEMD-ANN and EEMD-MLR models increased by 52.9% and 41.0%, respectively, indicating that the ANN model was more robust than the MLR model when simulating nonlinear SSC time series. Compared with EMD, EEMD can alleviate the mode mixing problem and significantly increase the simulation accuracy with the ANN and MLR models. Significance tests were employed to determine the strength of the physical meaning in each IMF component. Taking IMFs with significant (p

Accurate runoff modeling has an important role in water resource management. Attributable to the effects of climate variability and vegetation dynamics, runoff time series is nonstationary, resulting in the difficulty of runoff modeling. Detecting the temporal features of runoff and its potential influencing factors can help to increase the modeling accuracy. Selecting the Yihe watershed in the rocky mountainous area of northern China as a case study, multivariate empirical mode decomposition (MEMD) was adopted to analyze the time scales of the monthly runoff and its influencing factors, i.e., precipitation (P), normalized difference vegetation index (NDVI), temperature (T), relative humidity (RH), and potential evapotranspiration (PE). Using the MEMD technique, the original monthly runoff and its influencing factors were decomposed into six orthogonal and bandlimited functions, i.e., intrinsic mode functions (IMF1-6) and one residue, respectively. Each IMF is a counterpart of the simple harmonic function and represents a simple but general oscillatory mode in the original time series data. The results of the IMF contribution rate showed that the annual cycle had the most important role in runoff, P, NDVI, T and PE change. The contribution of quarterly oscillation was the largest contribution for the month RH variability. The monotonic residue showed that the predominant trends of runoff, P, NDVI, T, RH, and PE were decreasing from 2006 to 2015. Stepwise multiple linear regression (SMLR) was chosen to simulate the runoff IMFs and residue. The modeling results using the IMFs and residue of the potential influencing factors as input variables (R2 ranges from 0.53 to 1.0) were better than those using the original time series of influencing factors as input variables (R2 ranges from 0.17 to 0.6). By summing all the modeled IMFs and residues, the monthly runoff model was obtained, which increased the R2 value by 24.2% compared with the SMLR model using the original time series of influencing factors as input. The results indicated that MEMD was efficient for improving the accuracy of nonstationary runoff modeling.

Soil erodibility has confounded researchers for decades. Difficulties arise with initiation of motion, pore-water status, physical, and perhaps biological, material properties and type of applied energy (i.e., rainfall, runoff, freezing or thawing, wind). Though specific tests have been developed to determine critical shear stress and soil erodibility, solutions do not seem to conform to theory. We have models for erosion assessment and, although each provides practical information for planning and management, all share a need to improve predictions for soil detachment. Here, a series of submerged jet tests (JET) are performed on samples of three soils prepared to represent agricultural conditions (i.e., modest bulk density), five initial soil water contents are imposed during sample packing that affected soil void ratio, and four water potential gradients are imposed during jet testing. Results, for both coarse- and fine-grained soils, indicate that critical shear stress can be predicted with knowledge of the silt content, void ratio and water potential gradient, and soil erodibility can be predicted with knowledge of critical shear stress, clay content and void ratio. This study was limited by the number of soils examined; however, the results are thought provoking.

Seepage plays an important role in soil erosion in contour ridge systems. Seepage generated from subsurface flow causes hillslope instability by reducing the soil shear strength and mobilizing soil particles and can produce cave-like features called seepage undercuts that can lead to contour failure. As the main threat to contour plowing, seepage results in large amounts of soil erosion due to row grade. Models used to predict seepage over a time series will provide a basis for modeling soil erosion resulting from seepage in contour ridging systems. Understanding seepage and its effects will advance our knowledge regarding seepage erosion mechanisms in contour ridge systems. In this study, 23 treatments were arranged using an orthogonal rotatable central composite design to model a seepage time series, build a simple seepage prediction model and investigate the effects of row grade, field slope and ridge height on seepage discharge. Most of the seepage discharge time series followed an S-shaped curve. The seepage discharge processes were fit by an exponential model with a determination coefficients (R2) greater than 0.995. Furthermore, the physical meaning of the exponential model was consistent with the experimental results. The seepage discharge continuously increased before the inflection point and then decreased. Finally, the seepage discharge approached a steady value. The maximum seepage discharge growth rate was achieved within 14 min, and the seepage discharge became steady within 106 min. Second-order polynomial regression models were used to determine the total and predicted steady seepage discharge using independent variables of row grade, field slope and ridge height, which produced R2 values of 0.66 (p

Concentrated flow can induce rill and ephemeral gully erosion in contour ridging systems. To better understand the morphological features of rills, deposition characteristics in contour ridging systems and their influencing factors, rainfall simulation experiments were conducted considering four factors: field slope, row grade, ridge height and seepage discharge. The results showed that a simplified power equation that considered the maximum rill depth and length predicts the erosion volume better than an equation that only accounts for rill length, with prediction accuracies of R2 = 0.96 and R2 = 0.61, respectively. The ridge height could promote seepage and extend the maximum rill width and depth. The relationships between seepage and rill width, and seepage and soil loss could be fitted with quadratic equations. Seepage exerted a positive effect when the rill width and total soil loss were

Seepage in contour ridge systems is a common phenomenon that can exacerbate soil erosion, however, the characteristics of soil erosion under seepage conditions in contour ridge systems are not clear. The objective of this study was to analyze the soil erosion process under seepage conditions and quantify the effects and interactions between the ridge height, row grade, and field slope on runoff and sediment yield. Twenty-three treatments for these three factors were arranged by an orthogonal rotatable central composite design. A new type of experimental plot for simultaneously changing the row grade and field slope and creating seepage conditions was used to imitate the microtopographic relief of contour ridge systems. In each run, seepage samples from the row sideslope were collected every 2 min for 60 min, and then artificial rainfall simulation was performed for 30 min during which runoff samples were collected every 1 min. The results showed that four soil erosion sub-processes were observed, including interrill erosion, headward erosion, contour failure, and rill erosion. Second-order polynomial regression models predicted the sediment yield (R2 = 0.74) better than the runoff (R2 = 0.56). Interactions between these factors did not significantly affect the runoff or sediment yield even at p < 0.1. The row grade and field slope exerted a greater effect on the sediment yield than on the runoff, whereas the ridge height influenced the runoff more with an increasing positive effect. The effect of these three factors on sediment yield revealed a convex curve with an increasing factor value. The field slope exhibited a greater increasing effect before the maximum sediment yield occurred and a greater decreasing effect after that than the other two factors did. The maximum runoff and sediment yield occurred at similar row grades (7.5° and 7.1°, respectively) and field slopes (10.9° and 10.8°, respectively). However, the minimum runoff occurred at a ridge height of 6.7 cm, and the maximum sediment yield at a ridge height of 12 cm. The findings have important implications for assessing and modeling soil erosion in contour ridge systems.

We report the first direct measurement of decays of the Lambda(+)(c) baryon involving the neutron. The analysis is performed using 567 pb(-1) of e(+)e(-) collision data collected at root s = 4.599 GeV with the BESIII detector at the BEPCII collider. We observe the decay Lambda(+)(c) -> nK(S)(0)pi(+) and measure the absolute branching fraction to be B(Lambda(+)(c) -> nK(S)(0)pi(+)) = [1.82 +/- 0.23(stat) +/- 0.11(syst)]%. A comparison to B[Lambda(+)(c) -> p( (K) over bar pi)(0)] provides an important test of isospin symmetry and final state interactions.

Plastic film mulching is widely employed to improve crop yields. Mulching for the entire crop growth period is a widespread practice. However, a shorter plastic film mulching duration is suggested for obtaining larger grain yield recently. To quantify the effects of plastic film mulching durations on soil erosion and nutrient losses, a three-treatment experiment with three replicates was constructed in field. The designed treatments were control (M0, non-mulched treatment), mulching from sowing to the end of the peanut pod-setting stage (M1) and pod-filling stage (M2). Plastic film mulching significantly increased the mean runoff and sediment yield. With film mulching, the mean runoff and soil losses among M1 and M2 treatments had no significant difference, and significantly larger than that in M0 treatment. After mulching removing, there were no significant differences between the mean runoff and soil losses of M0 and M1 treatments. Compared with the M2 treatment, the M0 treatment had significantly reduced mean runoff and soil losses of all the events. Non-mulching increased the total nitrogen (TN) and total phosphorus (TP) losses. The M0 treatment had the highest TN (23.0 mg m−2) and TP (3.02 mg m−2) losses in the three treatments. The M2 treatment significantly reduced the TN and TP losses. In conclusion, mulching from sowing to the end of pod-setting stage was suggested as the appropriate choice for the largest yield and less soil erosion. But, some soil conservation measurements should be taken in furrow areas to effectively reduce soil erosion, under the condition of film mulching.

Pu-erh tea is a popular beverage in Southeast Asia, especially in many areas of China. Natural fungal inoculation and fermentation form its special quality and function in health care. At the same time, a common assumption is that unknown fungi from natural inoculation may pose a risk for safety of drinking the beverage, leading to an urgent need for a thorough fungal survey of Pu-erh tea. The present paper reports the natural fungal colonizations isolated from 60 representative samples. The results of the survey showed that the fungal colonizations were isolated from all the samples studied, ranging from 1.6 × 103 to 1.16 × 105 cfu/g, and 62 isolates were identified to belong to 41 species of 19 genera, including 13 species of Aspergillus and seven species of Penicillium, and 21 species of other genera. The predominant fungi were yeasts and different species of the genus Aspergillus. The concrete species of the dominant fungi varied with environment conditions of various production places. Sample parameters such as water content, AW, pH, polyphenol content were recorded, though they appeared to have no obvious effects on the total number of fungi, whereas processing and storage methods evidently affected total number of fungi. Some species of fungi such as Aspergillus fumigatus, Penicillium spp., Trichoderma spp. and Fusarium culmorum, etc., which maybe excrete toxic metabolites, were isolated in the survey. Further evaluation on the safety of these fungi isolated from Pu-erh tea products is needed. PRACTICAL APPLICATIONS This study investigated the fungal colonizatins exisiting in Pu-erh tea and some parameters concerning the storage of Pu-erh tea. These findings will help to evaluate the safety of Pu-erh tea products, and also facilitate the formulation of microbiologically sound methods for the manufacture and storage of Pu-erh tea, especially for the supervision of microbic fermentation during the process of ripe Pu-erh tea manufacture, thus contributing to avoid the contamination from toxigenic or potentially toxic fungi, and to ensure the safety of drinking Pu-erh tea.

An investigation was carried out on the potential features of 7075-T76 aluminum alloy under various constant stresses in 3.5% NaCl solutions. The applied stress accelerated the formation of electric double-layer at aluminum alloy/solution interface, and the formation time became shorter with the stress increasing. As the stress was applied, the fluctuating range and energy of potential noise improved in the low-frequency and reduced in the high-frequency while potential noise exhibited the characteristics of pitting corrosion. Potential fluctuation decreased gradually with time under loading. When the stress was released from the specimen, potential fluctuation weakened apparently, especially in the lower frequency range.

Nanopore technology for single molecule detection has a great potential in DNA sequencing and other bio-analytical applications. The magnitude of current signals can reach subnano-ampere level, the stability of signals and signals to noise ratio are very important in single molecule detection. In this work, a steady-state continuum-based model, composed of the coupled Poisson-Nernst-Planck equations was used for investigating the electroosmotic flow (EOF) inside the nanopore. The features of EOF were figured and the changes with the variables such as ion concentration, pore size were analyzed. A flat profile of EOF was discovered and some effective factors for inducing this kind flow were researched. Understanding the origin and the nature of this EOF profile especially to nanopore geometry is of great significance to develop solid-state nanopore technology. This may help to control the kinestate of nanoparticles inside the pore, analyze and discriminate those current signals, and even improve the stability of detecting signals. Keywordsnanopore; PNP equation; EOF; current signals

We present the first measurements of charge-dependent correlations on angular difference variables η 1 − η 2 (pseudorapidity) and ϕ 1 − ϕ 2 (azimuth) for primary charged hadrons with transverse momentum 0.15 ⩽ p t ⩽ 2 GeV / c and | η | ⩽ 1.3 from Au–Au collisions at s N N = 130 GeV . We observe correlation structures not predicted by theory but consistent with evolution of hadron emission geometry with increasing centrality from one-dimensional fragmentation of color strings along the beam direction to an at least two-dimensional hadronization geometry along the beam and azimuth directions of a hadron-opaque bulk medium.

Identified mid-rapidity particle spectra of pi(+/-), K+/-, and p((p) over bar) from 200 GeV p + p and d + Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (R-dAu) between protons (p + (p) over bar) and charged hadrons (h) in the transverse momentum range 1.2 < p(T) < 3.0 GeV/c is measured to be 1.19 +/- 0.05(stat) +/- 0.03(syst) in minimum-bias collisions and shows little centrality dependence. The yield ratio of (p + (p) over bar)/h in minimum-bias d + Au collisions is found to be a factor of 2 lower than that in Au + Au collisions, indicating that the Cronin effect alone is not enough to account for the relative baryon enhancement observed in heavy ion collisions at RHIC. (c) 2005 Elsevier B.V. All rights reserved.

In this study, improved cross-search, bicubic spline interpolation and finite element (FE) methods are implemented into conventional digital image speckle correlation algorithm in order to reduce correlation computational time, to increase deformation measurement accuracy, and to smooth deformation distribution. With the improved correlation algorithms, an integrated computer-aided-measurement system, called micro-digital image speckle correlation (/spl mu/-DiSC) is built. This system is then applied to characterize the thermal property and fracture behavior of the plastic ball grid array (BGA) assembly and underfill thin film, and employed to validate the material constitutive relationship for a flip chip package and the fatigue life prediction model for a BGA assembly. The demonstration results are found to be in good agreement with those obtained from thermo-mechanical analyzer (TMA), finite element modeling (FEM), moire/spl acute/ interferometry (MI), and accelerated temperature cycling (ATC) test. Therefore, the system can be used as an effective experimental tool to characterize properties of electronic materials and verify findings of theoretical and numerical models for the establishment of reliability design methodology.

We propose and demonstrate that multiparticle transverse correlation functions are promising observables of detecting minijet production in root s=1.8 TeV p (p) over bar collisions.

Multipion correlations arising from the symmetrization of the [ital n]-pion wave function affect the extracted information from two-pion correlation measurements. The influence of multipion correlations on a sample of like-pion pairs can be expressed as a multipion correlation factor, the distribution of which offers good sensitivity to the multipion correlation effect. Analyses of the multipion correlation factor for two Bevalac streamer chamber data samples of 2.1[ital A] GeV Ne+Pb and 1.8[ital A] GeV Ar+Pb collisions show that the multipion correlation effect in the former sample is greater than in the latter. This result mainly arises from the fact that the pion source for Ne projectiles is smaller than for Ar projectiles. The residual correlations in the reference sample are related to the multipion correlation factor in multipion events, which can be expressed as a residual correlation factor. The influence of multipion correlations on two-pion interferometry analyses arises from the ratio of the residual correlation factor to the multipion correlation factor.

We review the most important experimental results from the first three years of nucleus-nucleus collision studies at RHIC, with emphasis on results from the STAR experiment, and we assess their interpretation and comparison to theory. The theory-experiment comparison suggests that central Au+Au collisions at RHIC produce dense, rapidly thermalizing matter characterized by: (1) initial energy densities above the critical values predicted by lattice QCD for establishment of a Quark-Gluon Plasma (QGP); (2) nearly ideal fluid flow, marked by constituent interactions of very short mean free path, established most probably at a stage preceding hadron formation; and (3) opacity to jets. Many of the observations are consistent with models incorporating QGP formation in the early collision stages, and have not found ready explanation in a hadronic framework. However, the measurements themselves do not yet establish unequivocal evidence for a transition to this new form of matter. The theoretical treatment of the collision evolution, despite impressive successes, invokes a suite of distinct models, degrees of freedom and assumptions of as yet unknown quantitative consequence. We pose a set of important open questions, and suggest additional measurements, at least some of which should be addressed in order to establish a compelling basis to conclude definitively that thermalized, deconfined quark-gluon matter has been produced at RHIC., Comment: 101 pages, 37 figures; revised version to Nucl. Phys. A

A digital speckle image correlation system was developed to measure the in-situ micro-deformation of the solder joints in a flip chip on board (FCOB) assembly kubject to thermal cycling. The digital images acquired from deformed solder joint images captured at higher temperatures were correlated to the undeformed base image using a correlation algorithm. The deformation distributions in the solder joint were determined. A fmite element model was established to simulate the deformation of the assembly. The solder material constitutive model is viscoplastic and underfill material model is viscoelastic. The measurement results by correlation were then compared with the fmite element simulation results. It was found that U and V displacement fields of the solder joint obtained from the experiment and simulation agree well with each other. the strain fields are comparable.

A digital speckle image correlation system was developed to measure the in-situ micro-deformation of the solder joints in a flip chip on board (FCOB) assembly subject to thermal cycling. A pair of digital images acquired from an undeformed and deformed solder joint at certain temperature were correlated using a cross-search algorithm. As a result, deformation distributions in the solder joint were determined. Based on solder material's viscoplastic and underfill material's viscoelastic constitutive models, a finite element model was established to simulate the deformation of the assembly. The measurement results by correlation were then compared with the simulation results. It was found that U and V displacement fields of the solder joint obtained from the experiment and simulation are comparable.