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The present study investigated the changes in morphology, enzyme activities in the pancreas and mucosa, and nutrient transporter gene expression in the duodenum and jejunum in male and female pigeons during the incubation and chick-rearing periods. Forty-two pairs of White King pigeons with 2 fertile eggs per pair were randomly divided into 7 groups by different breeding stages. The crypt depth of the duodenum and jejunum reached the peak at day 1 (R1) and day 7 (R7) of chick rearing, respectively. The jejunum surface area increased to a maximum value at R1. Amylase activity in the pancreas decreased to the lowest value at R1, whereas trypsin and lipase activities peaked at 17 D of incubation (I17) and R7, respectively. In male pigeons, mucosal Na+-K+-ATPase activity in the duodenum and jejunum was the highest at R15 and it was at I17 in female pigeons. Jejunum sucrose activity in female pigeons was higher at I4 than that at I17 (P

The present study was carried out to investigate the changes in amino acid (AA) contents of crop milk and plasma and mRNA abundance of AA transporters and AA synthesis–related enzymes in the crop tissue of male and female pigeons during incubation and chick-rearing periods. Forty-two pairs of adult White King pigeons with 2 fertile eggs per pair were randomly divided into 7 groups by different breeding stages. The AA content of crop milk decreased from day 1 (R1) to day 25 (R25) of chick rearing (P

Acid deposition has been regarded as a serious factor in the deteriorative water environment and ecosystems. Despite the powerful acid emission control measures have been implemented by the Chinese government, many areas (especially Southeast China) are still suffering from acid deposition. The chemical and isotopic (δ34S and 87Sr/86Sr) compositions of rainwater in Hangzhou, a typical megacity in Southeast China with serious acid rain problem, for one year were studied with the aim to better constrain potential sources and explore the causes of rainwater acidification. Most rainwater samples were acidic, with a VWM pH value of 4.65. SO42− was the dominant anion and the main acid ion in rainwater. Sulfur isotope and the quantity equilibrium model revealed that sea salt, crustal, biogenic, and anthropogenic sulfur represented 2.3%, 0.1%, 16.7%, and 80.8% of the SO42− source in rainwater, respectively. The back trajectory and strontium isotopes indicated that the base cations (BCs) in rainwater originated mainly from anthropogenic sources. The relatively low neutralizing capacity caused by limited BCs input and emission control measures undermines some efforts to reduce rainwater acidity. This case study demonstrated that a valuable tool to probe the source of acid rain and unravel the mechanism of rainwater acidification can be provided by multiple lines of evidence, including rainwater chemical compositions, stable sulfur isotopes, and stable strontium isotopes.

Hydro-geochemical study of small catchment provides important information to identify water and solute sources, understand chemical weathering processes and their controlling factors. In this work, 44 small catchments on the southeastern Tibetan Plateau were investigated. Stream, precipitation, glacier and spring waters in both high and low flow seasons and bed rocks samples were analyzed with a main purpose to understand the processes controlling the stream water chemistry and quantify the weathering rates. The stream waters are mainly recharged by precipitation and glacier meltwater. Glacier meltwater and precipitation account for 25.8% and 73.9% of the total discharge in high flow season, and 44.4% and 54.1% in low flow season on average. Hydrograph separation and chemical mass balance are jointly used to estimate the contributions of major reservoirs (precipitation, glacier, spring, carbonates and silicates) to the total dissolved loads of the streams. Rock weathering accounts for ~90% of the total dissolved cations for most streams. Silicate and carbonate weathering account for 15.9% and 75.2% of total dissolved cations in high flow season, and 9.5% and 77.2% in low flow season on average. Lack of basic hydrological data in the ungauged remote area is a problem for quantified weathering study. The Noah LSM model is applied to obtain the annual runoff of these un-gauged catchments in this study. Based on these approaches, the chemical weathering rates and total denudation rates (TDR) are calculated for each of the small catchments. The silicate cation weathering rates (SCWR) range between 0.6 and 5.2 t/km2/yr, with the area-weighted mean value about 1.8 t/km2/yr. The TDR range between 8.9 and 1907.9 t/km2/yr. The comparisons between the small catchments and with other river basins in different tectonic and climatic environments indicate that lithology, climatic factors (temperature and runoff) and physical erosion rate are the key parameters controlling chemical weathering rate. The average SCWR of the small catchments is about 6 times higher in high flow season than in low flow season, which could be attributed to the higher temperature and runoff in high flow season. Meanwhile, the positive relationship between SCWR and TDR supports the view that physical erosion has an important effect on chemical weathering in the Tibetan Plateau.

Straw incorporation exerts important roles on greenhouse gas emissions and soil carbon (C) sequestration. However, few studies have comprehensively assessed the effects of straw incorporation on net global warming potential (NGWP) considering both emissions of greenhouse gas (GHG) and accumulation of SOC in Northeast China, the most important agricultural regions across the nation. An ongoing straw incorporation experiment was initiated in a maize cropping system of Northeast China from 2010, including three treatments: no straw incorporation (CK), incorporation of maize straw at a low level of 4000 kg ha −1 (S 4 ), and at a high level of 8000 kg ha −1 (S 8 ). At 2015, the crop yield was significantly elevated (11% and 21% for S 4 and S 8 , respectively) by the straw additions resulting from improved soil fertility. During the growing season of 2015, we found that the straw additions did not affect seasonal patterns of the N 2 O and CH 4 , but changed their seasonal magnitudes. Averaged over this period, CH 4 flux was very low based on its GWP, and straw incorporation tended to reduce the CH 4 emissions (6.6, 3.6 and 4.3 kg CO 2 eq ha −1 for CK, S 4 and S 8 , respectively); while straw incorporation significantly enhanced N 2 O emissions with the value of 429, 590 and 746 kg CO 2 eq ha −1 for CK, S 4 and S 8 , respectively. On the other hand, a significantly linear relationship (SOC sequestration rate = 0.29 × annual C input–0.57, R 2 = 0.99, P 0.05) was detected between annual straw C input and SOC sequestration rate over the 5-year cycles, indicating the soil we studied was still not C-saturated at least during the experimental interval. More notably, the C conversion rate (29%, the slope of the equation) was generally larger than the values reported in other region of China. These results implied and confirmed that the soil of Northeast China possessed greater potentials to sequestrate external C. Taken together, the SOC accumulation accounted for major portion of the NGWP and counteracted the extra emissions of GHGs (492, −1183 and −3040 kg CO 2 eq ha −1 for NGWP of CK, S 4 and S 8 , respectively). Therefore, the agricultural practise of straw incoporation was strongly recommended to be adopted in Northeat China to improve the soil productivity and simultaneously mitigate the negative influence of GHG emissions.

Hydrocarbon reservoir production generally results in observable time-lapse physical property changes, such as velocity increases within a compacting reservoir. However, the physical property changes that lead to velocity changes can be difficult to isolate uniquely. Thus, integrated hydro-mechanical simulation, stress-sensitive rock physics models and time-lapse seismic modelling workflows can be employed to study the influence of velocity changes and induced seismic anisotropy due to reservoir compaction. We study the influence of reservoir compaction and compartmentalization on time-lapse seismic signatures for reflection amplitude variation with offset (AVO) and azimuth (AVOA). Specifically, the time-lapse AVO and AVOA responses are predicted for two models: a laterally homogeneous four-layer dipping model and a laterally heterogeneous graben structure reservoir model. Seismic reflection coefficients for different offsets and azimuths are calculated for compressional (P–P) and converted shear (P–S) waves using an anisotropic ray tracer as well as using approximate equations for AVO and AVOA. The simulations help assess the feasibility of using time-lapse AVO and AVOA signatures to monitor reservoir compartmentalization as well as evaluate induced stress anisotropy due to changes in the effective stress field. The results of this study indicate that time-lapse AVO and AVOA analysis can be applied as a potential means for qualitatively and semi-quantitatively linking azimuthal anisotropy changes caused by reservoir production to pressure/stress changes.

By employing the first order shear deformation plate theory and the Bloch–Floquet theorem, the dispersion equation of flexural wave in the periodic composite plate structure with piezoelectric patches is derived and solved by the use of the differential quadrature element method. Moreover, wave modes for the dispersion curves of the considered periodic plate are compared with those of a homogeneous plate, from which the reason of the frequency band gap is revealed. Then, a comprehensive parametric study is conducted to highlight the influences of the physical parameters and the geometrical parameters on the frequency band gaps. The results show that the method is efficient and accurate and the bandwidth can be enlarged by changing the physical and geometrical parameters. The special band gap property of periodic plate structure has many potential applications in wave/vibrations attenuation areas for mechanical, aerospace and civil engineering structures.

InAs 1− x Sb x films with x = 0.06 were grown on InAs (1 0 0) substrates by liquid phase epitaxy (LPE). Different purification procedures were applied to get InAsSb samples with different carrier concentration. The complete optical absorption spectra including absorption edge and intrinsic absorption region of InAsSb samples were extracted from the room temperature transmission spectra. The energy band gaps of InAsSb samples were obtained by fitting the intrinsic absorption spectra, giving rise to the values of 303.4–305.1 meV. The reciprocal slope ( E o ) of the absorption edge related to the carrier concentration was also determined. The E o value decreases with decrease of InAsSb epilayer carrier concentration.

The origin of atmospheric dissolved organic nitrogen (DON) deposition is not very clear at present. Across China, the DON deposition was substantially larger than that of world and Europe, and we found significant positive correlation between contribution of DON and the deposition flux with pristine site data lying in outlier, possibly reflecting the acute air quality problems in China. For a case study in Northeast China, we revealed the deposited DON was mainly derived from intensive agricultural activities rather than the natural sources by analyzing the compiled dataset across China and correlating DON flux with NH 4 + –N and NO 3 − –N. Crop pollens and combustion of fossil fuels for heating probably contributed to summer and autumn DON flux respectively. Overall, in Northeast China, DON deposition could exert important roles in agro-ecosystem nutrient management and carbon sequestration of natural ecosystems; nationally, it was suggested to found rational network for monitoring DON deposition.

We investigated the effect of combined salinity and drought stress on ion accumulation, membrane permeability in leaves, and seedling survival and shoot dry weight of Suaeda physophora seedlings after they were rewatered. The results showed that drought stress increased leaf Na + and Cl - content, especially at 400mmol· L -1 NaCl pretreatment, while drought treatment had no effect on leaf K + content after seedlings were pretreated with either 1 or 400mmol· L -1 NaCl. Shoot dry weight of seedlings decreased during drought treatment compared to control (without drought treatment) regardless the concentrations of salinity after seedlings were rewatered. Drought treatment had less adverse effect on the seedling and leaf survival in seedlings pretreated at 400mmol· L -1 NaCl than at 1 mmol· L -1 NaCl after seedlings were rewatered. The present results indicate that seedlings of S. physophora pretreated with salinity can increase seedling survival, and this can help them to adapt to combined salinity and drought stress in arid areas. KEYWORD: Suaeda physophora; Salinity; Drought; Shoot dry weight

An effective technique for flaw detection of composites is proposed. In this technique, the detection problem is formulated as an optimization problem minimizing the difference between the measured and calculated surface displacement response derived from scattered elastic-wave fields. A combined optimization technique of using an improved μGA and a local optimizer is developed to solve the optimization problem so as to obtain the flaw parameters defining flaw configurations. Guidelines for implementing the detection technique, including formulation of the objective function of the optimization problem using different error norms, improvement of μGA convergence performance, switch from μGA to local optimizer in optimization process, and suppression of the effect of noise on detection results, are addressed in detail. Numerical examples are presented to demonstrate the effectiveness and efficiency of the proposed detection technique.

A method of damage detection for composite plates using Lamb waves and a projection genetic algorithm is investigated in this study. This method first formulates the damage detection as an optimization problem of minimizing the error between the measured and calculated surface displacement response derived from Lamb waves. The calculated response is obtained by using the strip element method with the trial crack parameters (location, size). Then a projection genetic algorithm is used to solve the optimization problem and thus identify the actual crack parameters. The projection genetic algorithm is developed from the hybridization of the modified micro-genetic algorithm with a projection operator. It has an excellent convergence performance, taking only 9.9 ∼ 14.2% of the number of function evaluations required by the conventional micro-genetic algorithm to obtain the global optima for six benchmark functions. Numerical examples are presented to verify the proposed method for detection of cracks inside composite plates. The maximal error of detected crack parameters is -4.3% for four simulated cases, which is achieved by running only 60 generations of projection genetic algorithm.

A concept of total solution for structural mechanics problems is proposed in this paper. It aims to establish a systematic approach to provide a comprehensive solution for practical structural mechanics problems, especially for traditional forward problems with incomplete input information (load, material property, boundary condition) and inverse problems with insufficient observations of effects (displacement, acceleration, stress, etc.). The approach for a total solution is to formulate such a structural mechanics problem as a parameter identification problem based on the forward solver of problem. All the unknown parameterized information in this forward model is determined through an iterative procedure of conducting alternately forward and inverse (or mixed) analyses. Algorithms of implementing inverse and mixed analyses are developed, which include a sensitivity matrix-based method and a modified adaptive neural networks method. Numerical investigations have been made to demonstrate the feasibility and validity of the proposed approach as well as the implementation algorithms.

In this paper, a procedure is suggested for characterizing the material properties of functionally graded material (FGM) plate by the use of a modified hybrid numerical method (HNM) and a neural network (NN). The modified HNM is used to calculate the displacement responses of FGM plate to an incident wave for a known material property. The NN model is trained by using the results from the modified HNM. Once trained by, the NN model can be used for on-line characterization of material properties if the dynamic displacement responses on the surface of the FGM plate can be obtained. The material property so characterized is then used in the modified HNM to calculate the displacement responses. The NN model would go through a progressive retraining process until the calculated displacement responses obtained by using the characterized result is sufficiently close to the actual responses. This procedure is examined for two sets of material properties of a SiC–C FGM plate. It is found that the present procedure is very robust for determining material property distributions in the thickness direction of FGM plates.

In this study, an adaptive multiplayer perceptron (MLP) technique is proposed for the detection of cracks in anisotropic laminated plates. The displacement response on the surface of plate, excited by a time-harmonic line load, is used as the input of the MLP. The crack parameters that specify the location and size of the cracks in the anisotropic laminated plates are taken as the output of the MLP. The MLP model is first trained to establish the nonlinear relationship between the scattered surface displacement response and the corresponding location and size of the cracks. The scattered displacement responses required in training samples are calculated from the strip element method (SEM). To facilitate this training process, the correlation analysis for the outputs of neurons in the hidden layers of the MLP model is carried out to optimize the MLP architecture. A modified back-propagation learning algorithm with a dynamically adjusted learning rate and an additional jump factor is developed to speed up the convergence of the MLP model in the training process. The concept of orthogonal array is adopted to generate the representative combinations of the crack parameters, which significantly reduces the number of samples while maintaining the completeness of sample data. The well-trained model is then used to reconstruct the crack parameters by feeding in the measured displacement response on the plate surface. These reconstructed crack parameters are further examined by comparing their resulting displacement response from the SEM forward calculation with the measured displacement response. If the comparison is satisfactory, the reconstructed crack parameters would be considered to be true and the computation ends. Otherwise, the MLP model would go another round of re-training process until the satisfactory reconstruction is obtained. The proposed technique was verified numerically using an anisotropic laminated plate [C0/G+45/G–45]s with four types of horizontal cracks. The verification includes the detection for both the location and the size of cracks using the simulated response data with and without noise.

The concept of Morita equivalence of matrix subrings with identity and of categories of modules is extended to "Morita-like" equivalence. This enables the generalizations of the theorems of Morita, Garcia, and Xu from the module of N × N matrices over a ring R to the module of Γ × Γ matrices, where Γ is an arbitrary indexing set.

The main characteristic of this interferometric system is such that the systems can be used for DCN laser (λ=195μm, 190μm) and also for HCN laser (λ=337μm) by changing the work medium, regulating the temperature of tube wall and adjusting the optic path, without changing any optic element.