多孔柔性载体在非流化状态下处理污水的效能

对自行研制的多孔柔性载体在非流化状态下，处理低浓度有机污水的效能及生物活性进行了考察，结果表明，效果比较理想，反应器内生物活性较高，值得进一步研究与探讨。

多孔柔性载体在非流化状态下处理污水的效能

对自行研制的多孔柔性载体在非流化状态下，处理低浓度有机污水的效能及生物活性进行了试验，结果表明：污水经处理后，检测指标ＣＯＤｃｒ去除率８０％以上，ＢＯＤ５去除率９０％以上；多孔柔性载体表面附着生物活性较高，可作为良好的生物载体。

NUMERICAL SIMULATION OF THERMAL NON-EQUILIBRIUM RADIATION ON UNSTRUCTURED GRIDS

A numerical method is developed based on an unstructured mesh to compute an ionized hypersonic flowfield with radiation in the thermo-chemical nonequilibrium. The flowfield is described by multi-species NavierStocks equations. The chemical model includes 11 species （O2, N2, O, N, NO, NO^＋ , N^＋ , O^＋, N2^＋ , O2^＋, e^- ） and 20 reactions. For simulating the thermal non-equilibrium effect, the two-temperature model is considered. The finite volume method （FVM） used for the spatial and directional discretization of radiative transfer equation（RTE） is described for unstructured grids. The numerical code can handle different kinds of species and radiative bands in a gas thermodynamicly described by two temperatures. In particular, the Delta, Epsilon, Beta prime, and Gamma prime bands of NO are choosen and the distribution of the radiation intensity is obtained.

Experimental Study on Gas-Solid Mass Transfer in Circulating Fluidized Beds

This study is devoted to gas-solid mass transfer behavior inheterogeneous two-phase flow. Experiments were carried out in a coldcirculating fluidized bed of 3.0 m in height and 72 mm in diameterwith naphthalene particles. Axial and radial distributions ofsublimated naphthalene concentration in air were measured with an on-line concentration monitoring system HP GC-MS. Mass transfercoefficients were obtained under various operating conditions,showing that heterogeneous flow structure strongly influences theaxial and radial profiles of mass transfer coefficients.

Local Liquid Side Mass Transfer Model in Gas-Liquid-Solid Three-Phase Flow Airlift Loop Reactor for Newtonian and Non-Newtonian Fluids

A small scale isotropic mass transfer model was developed for the local liquid side mass transfer coefficients in gas-liquid-solid three-phase flow airlift loop reactor for Newtonian and non-Newtonian fluids. It is based onHigbie's penetration theory and Kolmogoroff's theory of isotropic turbulence withwhere ε1 is local rate of energy dissipation, Af is the local microscale, η1 is the local Kolmogoroff scale and D is the diffusion coefficient. The capability of the proposed model is discussed in the light of experimental data obtained from 12 L gas-liquid-solid three-phase flow airlift loop reactor using Newtonian and non-Newtonian fluids. Good agreement with the experimental data was obtained over a wide range of conditions suggesting a general applicability of the proposed model.

NONPARALLEL BOUNDARY LAYER STABILITY IN HIGH SPEED FLOWS

The parabolized stability equations （PSEs） for high speed flows, especially supersonic and hypersonic flows, are derived and used to analyze the nonparallel boundary layer stability. The proposed numerical techniques for solving PSE include the following contents： introducing the efficiently normal transformation of the boundary layer, improving the computational accuracy by using a high-order differential scheme near the wall, employing the predictor-corrector and iterative approach to satisfy the important normalization condition, and implementing the stable spatial marching. Since the second mode dominates the growth of the disturbance in high Mach number flows, it is used in the computation. The evolution and characteristics of the boundary layer stability in the high speed flow are demonstrated in the examples. The effects of the nonparallelizm, the compressibility and the cooling wall on the stability are analyzed. And computational results are in good agreement with the relevant data.

Influences of strain softening and seepage on elastic and plastic solutions of circular openings in nonlinear rock masses

Considering the influence of strain softening, the solutions of stress, displacement, plastic softening region radius and plastic residual region radius were derived for circular openings in nonlinear rock masses subjected to seepage. The radial stress distribution curve, ground reaction curve, and relation curve between plastic softening region radius and supporting force in three different conditions were drawn respectively. From the comparisons among these results for different conditions, it is found that when the supporting force is the same, the displacement of tunnel wall considering both seepage and strain softening is 85.71% greater than that only considering seepage. The increase values of radial displacement at 0.95 m and plastic softening region radius at 6.6 m show that the seepage and strain softening have the most unfavorable effects on circular opening stability in strain softening rock masses.

Velocity of a Liquid Drop with a Sorption-Controlled Surfactant

The terminal velocity of a liquid droplet settling in a sulfactant solution has been studied for the non-linear adsorption Langmuir frameworks accounting for monolayer saturation and non-ideal surfactant interactions. Most prior research uses a linear adsorption model which cannot capture these effects, The Maragoni migration of a liquid drop settling through a surfactant solution is examined by using Langmuir framework. The solution concentration Ceq is assumed large enough for the surfactant mass transfer to be adsorption-controlled. Langmuir model generates non-linear Marangoni stresses which diverge in the limit of approaching ∝, strongly retarding U'.

Predictors of esophageal varices and first variceal bleeding in liver cirrhosis patients

To assess “predictors” of esophageal varices (EV) and variceal bleeding using non-invasive markers in Albanian patients diagnosed with liver cirrhosis. METHODSOne hundred thirty-nine newly diagnosed cirrhotic patients without variceal bleeding were included in this analysis. Model for end-stage liver disease (MELD), aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio (AST/ALT), AST to platelet ratio index (APRI), platelet count to spleen diameter (PC/SD), fibrosis-4-index (FIB-4), fibrosis index (FI) and King’s Score were measured for all participants. All patients underwent endoscopic assessment within two days of hospitalization. The major end point was the first esophageal variceal bleeding (EVB) event. The diagnostic performance of “predictors” for the presence of EV and EVB were assessed by sensitivity and specificity values obtained from the receiver operating characteristics procedure. RESULTSFIB-4 was the only strong and significant “predictor” of esophageal varices (multivariable-adjusted OR = 1.57 for one unit increment; 95%CI: 1.15-2.14). Furthermore, a cut-off value of 3.23 for FIB-4 was a significant predictor of esophageal varices, with a sensitivity of 72%, a specificity of 58% and a proportion of area under the curve (AUC) of 66% (P = 0.01). During the follow-up (median: 31.5 mo; interquartile range: 11-59 mo), 34 patients (24%) experienced a first EVB. FIB-4 was a poor predictor of EVB (the AUC was only 51%) for a cut-off value of 5.02. Furthermore, the AUC of AST/ALT, APRI, PC/SD, FI, MELD and King’s Score ranged from 45% to 55%. None of the non-invasive markers turned out to be a useful predictor of EVB. CONCLUSIONDespite the low diagnostic accuracy, FIB-4 appears the most efficient non-invasive liver fibrosis marker which can be used as an initial screening tool for cirrhotic patients.

The Effective AC Response of Nonlinear Composites

A perturbative approach is used to study the AC response of nonlinear composite media, which obey a current-field relation of the form with components having nonlinear response at finite frequencies. For a sinusoidal applied field, we extend the local potential in terms of sinusoidal components at fundamental frequency and high-order harmonic frequencies to treat the nonlinear composites. For nonlinear composite media with a low concentrations of spherical inclusions, we give the formulae of the nonlinear effective AC susceptibility at the third harmonic frequency.

Thermo-Magneto-Electric Currents with Dynamical Magnetization Inhomogeneities

We study the effect of potential and thermal gradient induced non-equilibrium magnetization in quasi1-d itinerant magnets.A semi-phenomenological theory is employed in conjunction with the drift-diffusion model forthis study.Using the methods of non-equilibrium thermodynamics,we derive the transport currents correspondingto charge,heat,and magnetization flows in the presence of non-equilibrium magnetization textures.It is shown howtime-dependent magnetic textures give rise to charge and thermal currents even in the absence of external potential andthermal gradients through spin pumping.The presence of dynamical textures also affect the thermodynamic parametersof the system.As an application,we consider the case of a helimagnet.

Strong Current-Polarization and Negative Differential Resistance in FeN3-Embedded Armchair Graphene Nanoribbons

Motivated by the recent advances of transition-metal-nitrogen-carbon (TM-N-C) materials in catalysis, we investigate the electronic structure and transport properties of FeN3-embedded armchair and zigzag graphene nanoribbons (FeN3@AGNRs, FeN3@ZGNRs) with different widths. The first-principles results indicate that the FeN3 induces significant changes on the band structures of both ZGNRs and AGNRs, making the resultant systems quite different from the pristine ones and own room-temperature stable ferromagnetic (FM) ground states. While only FeN3@AGNRs possess a significant spin-dependent negative differential resistance (NDR) and a striking current polarization (nearly 100%) behaviors, due to that FeN3 introduces two isolated spin-down states, which contribute current with different performances when they couple with different frontier orbits. It is suggested that by embedding FeN3 complexes, AGNRs can be used to build spin devices in spintronics.

Tracking control of chaotic dynamical systems with feedback linearization

A new method was proposed for tracking the desired output of chaotic dy- namical system using the feedback linearization and nonlinear extended statement ob- server method. The feedback linearization was used to convert the nonlinear chaotic system into linear system. The extended Luenberger-like statements observer was de- signed to reconstructing and observing the unmeasured statements when the tracking controller was designed. By this way, the chaotic system could be forced to track vari- able desired output, which could be a time variant function or an equilibrium points. Taken the Lorenz chaotic system as example, the simulation results show the validity of the conclusion and effectiveness of the algorithm.

Wavelet Analysis and Nonparametric Test for Climate Change in Tarim River Basin of Xinjiang During 1959-2006

Using wavelet analysis,regression analysis and the Mann-Kendall test,this paper analyzed time-series(1959-2006) weather data from 23 meteorological stations in an attempt to characterize the climate change in the Tarim River Basin of Xinjiang Uygur Autonomous Region,China.Major findings are as follows:1) In the 48-year study period,average annual temperature,annual precipitation and average annual relative humidity all presented nonlinear trends.2) At the 16-year time scale,all three climate indices unanimously showed a rather flat before 1964 and a detectable pickup thereafter.At the 8-year time scale,an S-shaped nonlinear and uprising trend was revealed with slight fluctuations in the entire process for all three indices.Incidentally,they all showed similar pattern of a slight increase before 1980 and a noticeable up-swing afterwards.The 4-year time scale provided a highly fluctuating pattern of periodical oscillations and spiral increases.3) Average annual relative humidity presented a negative correlation with average annual temperature and a positive correlation with annual precipitation at each time scale,which revealed a close dynamic relationship among them at the confidence level of 0.001.4) The Mann-Kendall test at the 0.05 confidence level demonstrated that the climate warming trend,as represented by the rising average annual temperature,was remarkable,but the climate wetting trend,as indicated by the rising annual precipitation and average annual relative humidity,was not obvious.

Optimal nonlinear excitation of decadal variability of the North Atlantic thermohaline circulation

Nonlinear development of salinity perturbations in the Atlantic thermohaline circulation(THC) is investigated with a three-dimensional ocean circulation model,using the conditional nonlinear optimal perturbation method.The results show two types of optimal initial perturbations of sea surface salinity,one associated with freshwater and the other with salinity.Both types of perturbations excite decadal variability of the THC.Under the same amplitude of initial perturbation,the decadal variation induced by the freshwater perturbation is much stronger than that by the salinity perturbation,suggesting that the THC is more sensitive to freshwater than salinity perturbation.As the amplitude of initial perturbation increases,the decadal variations become stronger for both perturbations.For salinity perturbations,recovery time of the THC to return to steady state gradually saturates with increasing amplitude,whereas this recovery time increases remarkably for freshwater perturbations.A nonlinear(advective) feedback between density and velocity anomalies is proposed to explain these characteristics of decadal variability excitation.The results are consistent with previous ones from simple box models,and highlight the importance of nonlinear feedback in decadal THC variability.

Installation position determination of wind speed sensors on steel pole along a high-speed railway

In order to consider the influence of steel pole on the measurement of wind speed sensors and determinate the installation position of wind speed sensors, the flow field around wind speed sensors was investigated. Based on the three-dimensional steady Reynolds-averaged Navier-Stokes equations and k-ε double equations turbulent model, the field flow around the wind speed sensor and the steel pole along a high-speed railway was simulated on an unstructured grid. The grid-independent validation was conducted and the accuracy of the present numerical simulation method was validated by experiments and simulations carried out by previous researchers. Results show that the steel pole has a significant influence on the measurement results of wind speed sensors. As the distance between two wind speed sensors is varied from 0.3 to 1.0 m, the impact angles are less than ±20°, it is proposed that the distance between two wind speed sensors is 0.8 m at least, and the interval between wind speed sensors and the steel pole is more than 1.0 m with the sensors located on the upstream side.

Responses of River Runoff to Climate Change Based on Nonlinear Mixed Regression Model in Chaohe River Basin of Hebei Province, China

Taking the nonlinear nature of runoff system into account,and combining auto-regression method and multi-regression method,a Nonlinear Mixed Regression Model (NMR) was established to analyze the impact of temperature and precipitation changes on annual river runoff process. The model was calibrated and verified by using BP neural network with observed meteorological and runoff data from Daiying Hydrological Station in the Chaohe River of Hebei Province in 1956–2000. Compared with auto-regression model,linear multi-regression model and linear mixed regression model,NMR can improve forecasting precision remarkably. Therefore,the simulation of climate change scenarios was carried out by NMR. The results show that the nonlinear mixed regression model can simulate annual river runoff well.

Factors Impacting Water Quality of a Small Stream in a Mountain Forest

Recent improvements to sewerage systems have meant that the relative contribution of point sources of pollution to the overall pollutant loads of streams has decreased markedly. Consequently, the potential increase in non-point source pollution means that it may be necessary to focus more on pollution loads from non-point sources in the future. This study examined pollution loads from non-point sources in streams flowing through forested areas. In addition, the relationship between runoff and pollution loads was also clarified. The small streams in the Tohoku University Botanical Gardens, in Sendai city, Japan, were sampled during a dry weather period and their water quality parameters were characterized. Chemical Oxygen Demand （COD） concentration increased with distance downstream, possibly because the soils in downstream areas contained high amounts of organic matter. Conversely, the concentration of nitrate nitrogen （NO3-N） decreased with distance downstream, probably because upstream soils were generally in an oxidized state while those further downstream were reduced. COD concentration increased with air temperature, while NO3-N levels decreased with an increase in air temperatures.

Validation of dynamic cavitation model for unsteady cavitating flow on NACA66

Unsteady cavitating flow is extremely complicated and brings more serious damages and unignorable problems compared with steady cavitating flow.CFD has become a practical way to model cavitation;however,the popularly used full cavitation model cannot reflect the pressure-change that the bubble experiences during its life path in the highly unsteady flow like cloud cavitating.Thus a dynamic cavitation model(DCM)is proposed and it has been considered to have not only the first-order pressure effects but also zero-order effect and can provide greater insight into the physical process of bubble producing,developing and collapsing compared to the traditional cavitation model.DCM has already been validated for steady cavitating flow,and the results were reported.Furthermore,DCM is designed and supposed to be more accurate and efficient in modeling unsteady cavitating flow,which is also the purpose of this paper.The basic characteristic of the unsteady cavitating flow,such as the vapor volume fraction distribution and the evolution of pressure amplitude and frequency at different locations of the hydrofoil,are carefully studied to validate DCM.It is found that not only these characteristics mentioned above accord well with the experimental results,but also some detailed transient flow information is depicted,including the re-entrant jet flow that caused the shedding of the cavity,and the phenomenon of two-peak pressure fluctuation in the vicinity of the cavity closure in a cycle.The numerical results validate the capability of DCM for the application of modeling the complicated unsteady cavitating flow.

Fenofibrate solid dispersion pellets prepared by fluid-bed coating:physical characterization,improved dissolution and oral bioavailability in beagle dogs

Solid dispersion of fenofibrate （FNB）, a poorly water-soluble drug, was prepared by a fluid-bed coating technique with PEG 6000 as the carrier. The physical state was characterized by DSC and X-ray powder diffractometry, which indicated the existence of fenofibrate in crystalline form in the solid dispersion. In vitro dissolution was studied in water containing 1% sodium lauryl sulfate, FASSIF and FESSIF. Significant enhancement in dissolution was achieved at PEG/FNB ratio of 4/1 with near complete dissolution within 30 min. Moderate improvement in dissolution rate was observed at smaller PEG/FNB ratios. Oral bioavailability was studied in beagle dogs after oral administration of fenofibrate solid dispersion pellets by monitoring fenofibric acid in plasma. The oral bioavailability of PEG/FNB 3/1 and 4/1 solid dispersion pellets was improved by 3.4 and 4.4-fold as compared to Lipanthyl, a commercial micronized fenotibrate formulation. There was a strong dependence of oral bioavailability on the in vitro dissolution rate. Good correlation was observed between the in vivo absorption fraction and the in vitro dissolution rate in each of the dissolution media, water containing 1% sodium lauryl sulfate, FASSIF and FESSIF. It could be concluded that PEG/FNB solid dispersion pellets were able to improve the dissolution and oral bioavailability of fenofibrate.