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Water retention behavior of clayey soils usually exhibits a hysteretic phenomenon, which can be attributed to the ink-bottle effect, different contact angle during wetting and drying process, entrapped air etc. For expansive soils, along the wetting and drying path, significant microstructure change is usually observed. The effect of microstructure change on the water retention hysteretic phenomenon was studied in this paper for an intact expansive clay from China, Mile clay. The soil water retention curve of Mile clay was obtained at the full suction range. The evolution of microstructure along wetting and drying path for Mile clay was characterized by pore sized distribution obtained from mercury intrusion porosimetry tests. Test results show that a strong hysteretic phenomenon was observed for suction ranging between 40 kPa and 15 MPa. This hysteretic phenomenon was mainly contributed to the different microstructure of specimens along wetting and drying paths with similar water ratio. For higher suction, as adsorption mechanism mainly contributed to the water retention properties, for specimens with similar water ratio, even with different maximum filled entrance pore sizes, the corresponding suction were similar with each other. For the lower suction, due to the completely drying historical state of specimens on the main wetting path, slightly different pore size distributions were observed for specimens on the main wetting and drying path with similar water ratio.

Complementary metal-oxide-semiconductor (CMOS) sensors can convert X-rays into detectable signals; therefore, they are powerful tools in X-ray detection applications. Herein, we explore the physics behind X-ray detection performed using CMOS sensors. X-ray measurements were obtained using a simulated positioner based on a CMOS sensor, while the X-ray energy was modified by changing the voltage, current, and radiation time. A monitoring control unit collected video data of the detected X-rays. The video images were framed and filtered to detect the effective pixel points (radiation spots). The histograms of the images prove there is a linear relationship between the pixel points and X-ray energy. The relationships between the image pixel points, voltage, and current were quantified, and the resultant correlations were observed to obey some physical laws.

This work try to optimize the flow field and concentration field of SCR system. Firstly, the original SCR system is simulated by Fluent and two kinds of guide plates are utilized. The simulation results show that the straight guide plate is slightly better than curve guide plate. The relatively standard deviation of velocity and concentration fields and pressure drop agree with the design rules. To verify the simulation results, a 1:10 scale cold plexiglass test plant is established and this plant is simulated correspondingly. The simulation results are in good agreement with experimental results. So the simulation results of original SCR system are credibly and can guide the practical engineering.

This study aims to investigate the suitability of volumetric-modulated arc therapy (VMAT) with RapidArc for primary leiomyosarcoma (LMS) in the spine, and present a new method to improve the target coverage and organs at risk (OAR) sparing. Five patients with LMS were retrospectively reviewed. The intensity-modulated radiotherapy (IMRT) with five coplanar beams (5b-IMRT) or seven coplanar beams (7b-IMRT), and VMAT using four quasi-quarter coplanar arcs (4q-VMAT) or two full coplanar arcs (2f-VMAT) were generated. Planning target volume (PTV) dose coverage, OAR dose sparing, conformity index (CI), and homogeneity index (HI) were evaluated. A hollow-cylinder model (HCM) was also used for feasible optimal beam arrangements. The mean doses to PTV were 95.2% ± 1.0%, 93.0% ± 1.0%, 97.9% ± 1.0% and 96.2% ± 1.5% for 4q-VMAT, 2f-VMAT, 5b-IMRT and 7b-IMRT respectively, while the mean maximum doses to spinal cord (SC) were 43.7 ± 0.9 Gy, 42.0 ± 0.8 Gy, 41.4 ± 1.2 Gy and 40.6 ± 1.4 Gy. Compared to 5b-IMRT, the mean doses delivered to kidneys decreased by about 35.1% (8.5 Gy), 2.5% (0.6 Gy) and 35.5% (8.6 Gy) for 4q-VMAT, 2f-VMAT, and 7b-IMRT, respectively. The CI proposed by Baltas et al.was twice as good with IMRT than with 4q-VMAT, and the numbers of monitor units were increased five- and threefold with 7b-IMRT and with 5b-IMRT compared to VMAT. The unexpected results we presented here show that VMAT technique can't achieve highly conformal treatment plans while maintaining SC sparing for LMS in the spine. An approach is proposed based on a hollow-cylinder model, but it is difficult to apply to clinical practice. In this case, VMAT is not superior to IMRT except for significant reduction in delivery time.

In this study, the phonon-based thermal conductivity of magnesite (MgCO3) and dolomite (CaMg(CO3)2) is calculated and compared with an earlier recent calculation on calcite (CaCO3). Equilibrium molecular dynamics simulation by way of the elegant Green-Kubo formalism is used for calculating the thermal conductivity. The thermal conductivity is investigated over a wide temperature range (from 200 K to 800 K) for all of the above mentioned materials. The most reliable potential parameters are used for characterising the interatomic interactions. In all of the models, two independent mechanisms are considered. The first is temperature independent, which is relevant to the acoustic short-range and optical phonons, and the other is temperature dependent, which is linked to the acoustic long-range phonons. In the study, the heat current autocorrelation function (HCACF) is calculated over the averages of the NPT, NVT and NVE ensembles in the x- and z- directions. In addition, it is shown that the optical, acoustic short- and long-range phonon modes are the main contributors to the decomposition model of the thermal conductivity. In a further investigation, the effects of the computational cell sizes on the thermal conductivity are investigated with five different simulation blocks containing 30, 240, 810, 1920 and 6480 atoms. Finally, this research provides a comparison of the thermal conductivity from this study and experimental studies: they are in good agreement.

Modifying crystal morphology was the key technology of the preparation of α-calcium sulfate hemihydrate from flue gas desulphurization gypsum using the hydrothermal method under atmospheric pressure. For exploring the mechanism of butane diacid effect on crystal morphology of α-calcium sulfate hemihydrate in preparation from flue gas desulphurization gypsum, the crystal morphology, convert ratio, and reaction process of α-calcium sulfate hemihydrate were studied by scanning electron microscope observation, and crystal water testing. The results showed, firstly, crystal modifier made the growth rates of crystal in all directions equal and made the crystal into hexagonal short column, by selectivity adsorbing on (111) crystal plane of α-calcium sulfate hemihydrate to form buffer film layer which hindered combining and growing of crystallization unit on the crystal plane of c-axis direction. Secondly, butane diacid was a good crystal modifier. When adding butane diacid of optimal amount of 0.02%~0.05%, the crystal morphology of α-calcium sulfate hemihydrate was satisfactory, the crystal length-diameter ratio was 1:1, but the convert ratio was only 91%~93%.

Purpose: studied the mechanism of polycarboxylicacid plasticizing effect on α-calcium sulfate hemihydrate. Methods: the adsorbed amount was tested by ultraviolet visible absorption spectrum method, ζ potential was measured by micro-electrophoresis analysis, and the corresponding workability was studied. Results: firstly, polycarboxylicacid plasticizer was adsorbed on α-calcium sulfate hemihydrate by Van Der Waals force and the saturated adsorption quantity of polycarboxylicacid plasticizer (HC) was about 5.8mg/g; secondly, the decisive factor for polycarboxylicacid plasticizer to disperse α-calcium sulfate hemihydrate particles was the steric hindrance of polycarboxylicacid plasticizer, and the maximum ζ potential of α-calcium sulfate hemihydrate with polycarboxylicacid plasticizer was-9.360mv, much less than β-calcium sulfate hemihydrate under the same conditions; finally, the perfect mixing content of polycarboxylicacid plasticizer was 0.3%~0.6%; it increased fluidity by 66%, to the maximum 300mm.

A fluorine anion modified CuNiAl hydrotalcite (CuNiAl-LDH (F-)) was prepared for the selective oxidation of glycerol (GLY) using O2 as oxidant. It was found that the obtained catalyst with typical layer structures of hydrotalcite compounds was an effective heterogeneous catalyst in GLY oxidation. Under the present conditions, the main product was the C3 oxygenated products of primary alcohol glyceric acid (GLYAC). The highest conversion of GLY reached 32.0% with 58.1% of the selectivity to GLYAC.

The recovery and utilization to building solid waste is the current hot issues in the construction of towns. In this paper, 30 groups of fly ash recycled concrete test cube were designed and produced, through the mechanical performance test research, we analysised the main influence factors to the strength and performances of fly ash regeneration concrete test cube,such as recycled aggregate category, water cement ratio, the admix proportion of recycled aggregate. The test results would lay a solid foundation for the test research and engineering application of recycled concrete.

Though the introduction of light rail transit status and the reinforcement of prestressed track beams, this paper explored the carbonation mechanism of prestressed track beams, and analysised the main influencing factors of prestressed track beams. Based on concrete carbonation depth forecasting model, this paper analysised the carbonation law of of prestressed track beams in Chongqing, and proposed the durability design measures to prestressed track beams.

Modifying crystal morphology was the key technology of the preparation of α-calcium sulfate hemihydrate from flue gas desulphurization gypsum using the hydrothermal method under atmospheric pressure. For exploring crystal modifier, the crystal morphology of α-calcium sulfate hemihydrate in preparation from flue gas desulphurization gypsum with various organic diacid was studied, by polarizing microscope profile observation. The results showed, When the space between two carboxyls was triplicate length of C-C, the organic diacid had the best effect of modifying crystal morphology.

Alkali activated slag cement was a new green cementing material with many performances. Whereas, high viscosity and bad workability of the fresh mixture were the matters to embarrass its application. For exploring the special superplasticizer, the adsorption characteristics of surfactant on slag was studied, by UV Vis Absorption Spectrum Method. The results showed, first, the adsorbed amount of cationic surfactant [CH3(CH2)11N(CH3)3]Cl was the highest value among the five surfactants, 12.8 mg/g. Second, the effect of alkali on the adsorbed amount of surfactant was complex. Cationic surfactant had cooperativity with alkali. But, adding water glass, the adsorbed amounts of the surfactants on slag were negative, because it was both colloid property and alkali solution property. Finally, the retarder of YP-3 made the adsorbed amount of ionic surfactant to increase, due to YP-3 contracted electric double layer in the surface of slag.

In order to solve the problem of needing to build accurate mathematical model in grounding grids fault diagnosis ,a new method for applying to the study of grounding grids fault diagnosis,which was based on BP neural network and improved by PCA theory，was introduced.The PCA(Principal component analysis)method was incorporated into the network,which not only solved the linear correlation of the input, but also simplified the network structure and reduced the parameters of neural net input. It realized optimum compression of fault sample data and enhanced classification speed and precision. The experimental results demonstrated that the method could decrease the number of the network input nerve cells effectively, and enhanced study efficiency and diagnosis accuracy. The way had very good fault distinguishing ability and vast prospect.

Hydraulic torque converter’s performance testing is very important in the product’s development and production. In order to accurately and rapidly test various performance parameters of the hydraulic torque converter, a torque converter performance test system was developed based on the PC and VB development platform in this paper. It can improve computing speed and programming capability, decrease artificial involved times, realize the data analysis processing’s automation.

Alkali activated slag cement and concrete are high strength, rapid hardening, low heat of hydration, good durability and so on. Whereas, too high viscosity and bad workability of the fresh mixture is the crux of the matter to embarrass application of alkali-activated slag cement and concrete. Development of special superplasticizer for alkali activated slag cement and concrete is a worth exploring way to solve the problem, and the study on the surface tension of simulated solutions of alkali activated slag cement system is one of the basic researches about the special superplasticizer. In this paper, the surface tension of surfactant-alkali-water was studied by Wilhelmy method. The results showed, first, water-glass had the best efficacity of several alkali activators, when the modulus of water-glass was 1.5 and dosage of water-glass by Na2O was 8%, the surface tension was reduced by 33 mN/m and reduced to 39.9mN/m; second, [CH3(CH2)9]2N(CH3)2Cl had the best efficacity of several surfactants, when the concentration of [CH3(CH2)9]2N(CH3)2Cl was 50g/L, the surface tension was reduced by 35.3 mN/m and reduced to 32.5 mN/m; finally, the effect of surfactant and alkali together on the surface tension of water was complex, surfactants had hardly effective in water glass.

A robust Capon adaptive beamforming imaging method was proposed for stepped-frequency through-the-wall radar. According to the ideal of robust Capon beamforming (RCB) under the steering vector uncertainty set, Capon optimal weight vector in frequcency domain is obtained by accurately estimating Compensation function vector. Then signal energy is estimated by freqency weighting, and coherence factor (CF) weighting is applied to suppress sidelobe level. Therefore, this method not only achieves higher resolution and much better interference suppression capabilities, but also improves imaging contrast.

A new image digital watermarking algorithm based on DWT is proposed, by which Arnold scrambling is firstly processed followed by wavelet decomposition in images. Then the watermark information is embedded in the processed digital images according to certain rules. The experimental results show that the algorithm has a better robustness against common attacks of JPEG and median filtering.

In the limestone/gypsum wet flue gas desulfurization pilot-scale test rig, key parameters such as SO2 absorption rate, mass transfer were experimentally determined.The results show that desulphurizing capacity of gypsum and fly ash is relatively weaker, which is only equivalent to fresh limestone with a content of 0.27% and 1.5% respectively. pH-t curve of slurry with different levels of fly ash could be divided into a sharply increasing stage and a steadily increasing stage. The leaching content of Mn2+ is about 9 times of Fe3+ , Mn2+ can form intermediate complex with HSO3- in the solution, which can induce catalytic reaction and accelerate SO2 absorption. Fly ash in gypsum slurry can obviously promote desulfurization. The pH value of slurry is high at the initial reaction stage, and effect of fly ash on SO2 absorption rate is less than 1.5%. when the pH value is decreased to 5.0, The leaching content of Mn2+ will grow with the decrease of pH value, better catalytic efficiency can be gained, effect of fly ash on SO2 absorption rate can increase 6.0% at most. The reaction is controlled by liquid phase resistance; the ratio of gas phase resistance to overall resistance is less than 38%. Mn2+ concentration of slurry increases with pH value decreasing and fly ash concentration increasing, which has significant effect on catalyzed oxidation of SO32-.

This paper studies the laws of crystal growth, percent conversion and the rate of reaction of α-calcium sulfate hemihydrate from FGD gypsum under different conditions using the hydrothermal method under atmospheric pressure. The crystal morphology was observed by using SEM, polarizing microscope profile, and percent conversion and the rate of reaction were obtained by assaying crystal water content and calculating. The results showed, (1) with the increase of reaction temperature, the dehydration rate increased and the formed α-calcium sulfate hemihydrate crystal had a larger particle size; (2) with the increase of salt concentration or slurry concentration, the formed α-calcium sulfate hemihydrate crystal was smaller, percent conversion and the rate of reaction was nearly unchanged; (3) with the increase of pH value of solution, the rate of reaction increased and percent conversion was nearly unchanged, and with pH value ranging from 5 to 7 the formed α-calcium sulfate hemihydrate crystal was crassitude. In conclusion, the perfect technological parameters were as follows: reaction temperature ranging from 95℃ to 100℃, salt concentration ranging from 15% to 20%, slurry concentration ranging from 15% to 20%, pH value ranging from 5 to 7, and reaction time not exceeding 90min.

We present a uniformly valid ray theory for body-wave propagation in laterally heterogeneous earth models. This is accomplished by implementing Maslov theory, which is a 3-D analogue of the widely used WKBJ seismogram method for spherically symmetric earth models. Away from caustics, complete seismic waveforms can be calculated by solving a system of 14 coupled first-order ordinary differential equations: four equations determine the ray geometry, eight additional equations determine the amplitude, and two further equations determine traveltime and attenuation. In the vicinity of a caustic, neighbouring rays cross, and asymptotic ray theory breaks down. Rather than considering the contribution to the wavefield of one single ray, our strategy is to express the wavefield in the vicinity of a caustic as a summation over neighbouring, non-Fermat rays based upon Maslov theory. Away from caustics, Maslov theory reduces to asymptotic ray theory. We present examples of the ray geometry in the 3-D model SKS12WM13, and demonstrate that small-scale triplications in the traveltime curve associated with large-scale heterogeneities in the lowermost mantle are ubiquitous. The theory is applicable to direct, turning and reflected waves, may to a limited extent be advanced to include head waves, but does not describe waves that are diffracted into the deep shadow. The determination of the geometric ray that connects a given source and receiver is based upon a ‘shooting’ method. Initial guesses for the take-off angles are determined based upon perturbation theory, which substantially reduces the number of iterations required to hit a receiver. Perturbation theory also provides predictions for arrival angles and amplitude anomalies. These predictions incorporate the effects of long-wavelength topography on internal boundaries and the free surface, and may be used as a basis for tomographic inversions. Generally, predictions based upon perturbation theory agree very well with exact 3-D ray tracing. Just as traveltime measurements provide constraints on velocity, arrival angles constrain velocity gradients, and amplitude anomalies put constraints on second derivatives in velocity. In SKS12WM13, traveltime anomalies can be as much as ±10 s, arrival-angle anomalies can be larger than ±5°, and 3-D amplitudes can differ by more than 100 per cent from PREM amplitudes.