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Natural gas hydrate (NGH) dissociation can cause many kinds of potential hazards. Dimensional analysis is used first to obtain the controlling factors for NGH dissociation-induced stratum's responses. And then the effects of the controlling factors on the deformation and stress distribution have then been numerically investigated. A simplified critical condition for judging the instability of gentle inclined stratum after NGH dissociation was proposed. It is shown that the maximum settlement is located near the upper part of the slide body while the soil uplifts near the lower part. The fast change of the stress and deformation is located at the interface between hydrate-bearing stratum (HBS) and over layer. The slope angle has the largest effects on the responses of the stratum. The effects of modulus and water depth on the stratum's instability are small. There is a critical extension length of dissociation zone over which landslide will occur which is determined by the strength parameters, slop...

Gas hydrate dissociation may lead to soil stratum instability such as marine landslides in hydrate-bearing sediments. In this paper, centrifugal tests were conducted to investigate the soil responses and stratum instability of a 14° slope during hydrate dissociation under centrifugal accelerations of 50 g and 100 g , different boundary conditions and heating modes. New phenomena such as sliding of the over layer, layered fractures between the hydrate layer and the over layer, and fractures in the over layer were observed. The fluid pressures, horizontal displacements and vertical displacements of the soils were measured and compared under different conditions. The observed mechanisms and decoupled formulations considering heat transfer, fluid seepage, soil deformation and critical soil failure were presented and discussed. The formation of layered fractures during hydrate dissociation is regarded as an important factor leading to the instability of the slope.

Gas hydrate (GH) dissociates owing to thermal injection or pressure reduction from the well in gas/oil or GH exploitation. GH dissociation leads to, for example, decreases in soil strength, engineering failures such as wellbore instabilities, and marine landslides. The FLAC3D software was used to analyze the deformation of the soil stratum and vertical wells with GH dissociation. The effects of Young’s modulus, internal friction angle, cohesion of the GH layer after dissociation, and the thickness of the GH layer on the deformation of soils were studied. It is shown that the maximum displacement in the whole soil stratum occurs at the interface between the GH layer and the overlayer. The deformation of the soil stratum and wells increases with decreases in the modulus, internal friction angle, and cohesion after GH dissociation. The increase in thickness of the GH layer enlarges the deformation of the soil stratum and wells with GH dissociation. The hydrostatic pressure increases the settlement of the soil stratum, while constraining horizontal displacement. The interaction between two wells becomes significant when the affected zone around each well exceeds half the length of the GH dissociation zone.

As for the rapid expansion of high-speed electrified railway industry, the current collection quality of electric locomotives becomes one of the crucial technical issues for the stable operation of trains. The key measurement index that can characterize the quality of current collection is the contact force between the catenary and pantograph on the locomotive roof. One of the major factors that affect the contact force is the contact wire irregularity, which appears to be very difficult to be measured or detected at present. In recent years, the frequency-domain indicators of the pantograph–catenary contact force (PCCF) have been gaining importance to address this issue. In this paper, a recent quadratic time–frequency distribution is selected to describe the time–frequency representation (TFR) of PCCF signal based on its nonstationarity. The Zhao–Atlas–Marks distribution (ZAMD) shows high time–frequency resolution and cross-term suppression for PCCF signals. To investigate the deterioration of the PCCF under contact wire irregularity, a pantograph–catenary interaction model is presented and verified. Some synthetic contact wire irregularities are generated and added to the interaction model. Based on the characteristics of quadratic TFRs of PCCF signals, a detection and localization approach for contact wire irregularity is proposed in this paper. The simulation and real-life experimental results indicate that the different forms of contact wire irregularity could be effectively detected and localized with meter accuracy using the ZAMD.

Debris flow is one of the major secondary mountain hazards following the earthquake. This study explores the dynamic initiation mechanism of debris flows based on the strength reduction of soils through static and dynamic triaxial tests. A series of static and dynamic triaxial tests were conducted on samples in the lab. The samples were prepared according to different grain size distribution, degree of saturation and earthquake magnitudes. The relations of dynamic shear strength, degree of saturation, and number of cycles are summarized through analyzing experimental results. The findings show that the gravelly soil with a wide and continuous gradation has a critical degree of saturation of approximately 87%, above which debris flows will be triggered by rainfall, while the debris flow will be triggered at a critical degree of saturation of about 73% under the effect of rainfalland earthquake (M>6.5). Debris flow initiation is developed in the humidification process, and the earthquake provides energy for triggering debris flows. Debris flows are more likely to be triggered at the relatively low saturation under dynamic loading than under static loading. The resistance of debris flow triggering relies more on internal frication angle than soil cohesion under the effect of rainfall and earthquake. The conclusions provide an experimental analysis method for dynamic initiation mechanism of debris flows.

The wind-induced vibration of the high-speed catenary and the dynamic behaviour of the pantograph–catenary under stochastic wind field are firstly analysed. The catenary model is established based on nonlinear cable and truss elements, which can fully describe the nonlinearity of each wire and the initial configuration. The model of the aerodynamic forces acting on the messenger/contact wire is deduced by considering the effect of the vertical and horizontal fluctuating winds. The vertical and horizontal fluctuating winds are simulated by employing the Davenport and Panofsky spectrums, respectively. The aerodynamic coefficients of the contact/messenger wire are calculated through computational fluid dynamics. The wind-induced vibration response of catenary is analysed with different wind speeds and angles. Its frequency-domain characteristics are discussed using Auto Regression model. Finally, a pantograph model is introduced and the contact force of the pantograph–catenary under stochastic wind i...

This paper presents a dual-percolation model coupling the percolation theory and the fracture percolation theory to study the conductivity of the fractured porous media. The Monte-Carlo method is used in the numerical simulation. First an appropriate computing scale by considering the calculation precision and elapsed time together is validated. Then, two parameters, A0 and D are presented in this model to determine the conductivity of the media. Generally the media can be blocked by itself in the condition of D > 2. However, the increase of pore connection and the randomness of fracture direction may release the selfblockage, increase the conductivity and make the dual porous media dissipated. A few long fractures can play a great role in the connection of media.

Compared with traditional fossil fuels, gas hydrates have vast reserves, cause little pollution, and are an essential strategic energy resource. Pipeline transportation is critical to realize the development and utilization of natural gas hydrate resources. The Eulerian multiphase flow model within the computational fluid dynamics software FLUENT was employed to calculate gas–liquid–solid flow, taking into account phase interactions, heat transfer, and collision among particles. Pipeline transportation of gas hydrate-bearing sediment (GHBS) particles was studied based on dimensional analysis and numerical simulation. First, the essential dimensionless numbers controlling multiphase flow and hydrate dissociation were deduced. Further, the obtained simulation results clearly indicate that when the system was in a stable state, there was a dissociation equilibrium height above which hydrate dissociated completely. The influences of the dimensionless numbers on the dissociation equilibrium height and friction coefficient in the pipe were determined, and power-law correlations for the dissociation equilibrium height and friction coefficient were obtained from the numerical data. Finally, an analytical expression of dissociation equilibrium height was derived by decoupling the solid–liquid flow and gas hydrate dissociation, and the validity of the power-law correlation for the dissociation equilibrium height was verified by the analytical expression.

The surface tension curves of three zwitterionic Gemini surfactants (GCS12, GCS14, and GCS16) were measured at different temperatures. According to the values of critical micelle concentration (cmc) and γcmc, the thermodynamic parameters of these surfactants were calculated. As temperature increases, the cmc values decrease, and the surface activities increase. The thermodynamic parameters indicate that the micellization and adsorption of these surfactants are spontaneous, endothermic and entropy-driven. The process of micellization and adsorption features an enthalpy-entropy compensation phenomenon. The compensation temperatures of micellization are in the range of 311.2~312.8 K, while those of adsorption are between 310.2 K and 312.2 K. Among these surfactants, GCS14 aggregates most easily into micelles, and the micelles of GCS14 are the most stable. Moreover, the mixed properties of GCS14 with anionic surfactant (SDS) and nonionic surfactant (CDA) were investigated, respectively. The GCS14/SDS mixtures exhibit excellent surface activities, and GCS14 plays an essential role in the mixtures. At αGCS14 = 0.8, the cmc and γcmc values reach a minimum. According to the regular solution theory, the great absolute values of βσ (for mixed monolayer formation at the aqueous solution/air interface) and βm (for mixed micelle formation in aqueous solution) indicate the strong attraction between GCS14 and SDS. The GCS14/SDS mixtures show synergistic effects in three properties, including the efficiency in surface tension reduction, the ability of micelle formation, and the ability of surface tension reduction. Also, the mixtures of GCS14 and CDA feature excellent surface activities. At αGCS14 = 0.8, the cmc and γcmc values reach a minimum. For the GCS14/CDA mixtures, the great absolute values of βσ and βm suggest these mixtures exhibit the synergistic effect in the surface tension reduction and the formation of the micelles. Zwitterionic Gemini surfactant GCS14 reveals stronger synergistic effects in the formation of mixed micelle and mixed monolayers with anionic surfactant (SDS) than with the nonionic surfactant (CDA). The molecule attraction between GCS14 and SDS or CDA in the mixed films is stronger than in the micelles.

Fengchun Wu,1,2,* Yue Zhang,2,3,* Yongzhe Yang,2–4 Xiaobing Lu,1,2 Ziyan Fang,1 Jianwei Huang,1 Lingyin Kong,3 Jun Chen,5,6 Yuping Ning,1,2 Xiaobo Li,7,8 Kai Wu2,3,5,6,9 1Department of Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, China; 2Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou, China; 3Department of Biomedical Engineering, School of Materials Science and Engineering, South China University of Technology (SCUT), Guangzhou, China; 4School of Medicine, South China University of Technology (SCUT), Guangzhou, China; 5Guangdong Engineering Technology Research Center for Diagnosis and Rehabilitation of Dementia, Guangzhou, China; 6National Engineering Research Center for Healthcare Devices, Guangzhou, China; 7Department of Biomedical Engineering, New Jersey Institute of Technology, NJ, USA; 8Department of Electric and Computer Engineering, New Jersey Institute of Technology, NJ, USA; 9Department of Nuclear Medicine and Radiology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan *These authors contributed equally to this work Background: Structural and functional brain abnormalities in schizophrenia (SZ) have been widely reported. However, a few studies have investigated both structural and functional characteristics in SZ patients at different stages to understand the neuropathology of SZ. Methods: In this study, we recruited 44 first-episode drug-naive SZ (FESZ) patients, 44 medicated chronic SZ (CSZ) patients, and 56 normal controls (NCs) and acquired their structural and resting-state functional magnetic resonance imaging (MRI). We then made group comparisons on structural and functional characteristics, including regional gray matter volume (GMV), regional homogeneity, amplitude of low-frequency fluctuation, and degree centrality. A linear support vector machine (SVM) combined with a recursive feature elimination (RFE) algorithm was implemented to discriminate three groups.Results: Our results indicated that the regional GMV was significantly decreased in patients compared with that in NCs; CSZ patients have more diffused GMV decreases primarily involved in the frontal and temporal lobes when compared with FESZ patients. Both FESZ and CSZ patients showed significant functional alterations compared with NCs; when compared with FESZ patients, CSZ patients showed significant reductions in functional characteristics in several brain regions associated with auditory, visual processing, and sensorimotor functions. Moreover, a linear SVM combined with a RFE algorithm was implemented to discriminate three groups. The accuracies of the three classifiers were 79.80%, 83.16%, and 81.71%, respectively. The performance of classifiers in this study with multimodal MRI was better than that of previous discriminative analyses of SZ patients with single-modal MRI.Conclusion: Our findings bring new insights into the understanding of the neuropathology of SZ and contribute to stage-specific biomarkers in diagnosis and interventions of SZ. Keywords: multimodal MRI, schizophrenia, support vector machine, SVM, classification

Dissociation processes of gas hydrate-bearing sediment particles in water flow condition were investigated. Experiments were carried out by observing a spherical CO2 hydrate-bearing sediment (CHBS) particle settling in water. The release process of gas bubbles from CHBS particles was recorded by a high-speed camera and the total time of dissociation was obtained for different particle diameters and water temperatures. An intrinsic dissociation model was presented based on the assumption that the dissociation rate of the CHBS particle is exponential with the concentration of remaining hydrate. The model considered the influences of changing temperature, pressure and the particle concentration on the dissociation rate. The constants in the model were obtained based on fitting the experimental data. The presented model can reveal the dissociation behavior of the CHBS particle.

A great number of studies have demonstrated the structural and functional abnormalities in chronic schizophrenia (SZ) patients. However, few studies analyzed the differences between first-episode, drug-naive SZ (FESZ) patients and normal controls (NCs). In this study, we recruited 44 FESZ patients and 56 NCs, and acquired their multi-modal magnetic resonance imaging (MRI) data, including structural and resting-state functional MRI data. We calculated gray matter volume (GMV), regional homogeneity (ReHo), amplitude of low frequency fluctuation (ALFF), and degree centrality (DC) of 90 brain regions, basing on an automated anatomical labeling (AAL) atlas. We then applied these features into support vector machine (SVM) combined with recursive feature elimination (RFE) to discriminate FESZ patients from NCs. Our results showed that the classifier using the combination of ReHo and ALFF as input features achieved the best performance (an accuracy of 96.97%). Moreover, the most discriminative features for classification were predominantly located in the frontal lobe. Our findings may provide potential information for understanding the neuropathological mechanism of SZ and facilitate the development of biomarkers for computer-aided diagnosis of SZ patients.慢性精神分裂症患者大脑的结构和功能异常已经被广泛报道，但是首发未用药精神分裂症患者和正常人的相关研究较少。本研究采集了 44 名首发未用药精神分裂症患者和 56 名正常人的结构和静息态功能磁共振图像，基于自动解剖标签模板提取了 90 个感兴趣区域的灰质体积、局部一致性、低频振荡振幅和度中心度作为特征，并将这些特征作为输入，用基于递归特征消除的支持向量机对首发未用药精神分裂症患者和正常人进行分类。结果表明，局部一致性和低频振荡振幅的组合为最佳分类特征，分类准确率达到 96.97%，并且分类权重最大的脑区主要位于额叶。研究结果有利于加深对精神分裂症神经病理机制的了解，有助于开发出用于临床辅助诊断的生物学标记物。.

Microscopic flow in fractured porous media is a typical problem for the exploitation of tight reservoirs. The rapid-flow in the fractured porous-media is of great significance to efficient and continuous oil/gas exploitation. The fractures are expected to enhance flow conductivity and mass transfer between matrix and fractures, and to improve oil displacement during water flooding. However, the fractures may also lead to water channeling under some conditions. The understanding on the mechanism of the microscopic flow in the fractured porous media has been insufficient until now. In this paper, a two-dimensional pore-fracture network model is presented to study the role of fractures in the flow. The effects of two main dimensionless parameters, fracture length to network length lf/l and fracture density Nf/N, on the absolute permeability and the oil displacement efficiency are investigated. The results show that the flow in the matrix plays a controlling role at a low fracture density. Once the fracture density exceeds a certain value, the flow is controlled by fractures. With the increase of the fracture density, the oil displacement efficiency develops into three typical stages: when Nf/N < 0.1, the oil displacement efficiency increases rapidly; when 0.1 < Nf/N < 0.5, the oil displacement efficiency changes slowly; and when Nf/N > 0.5, the oil displacement efficiency decreases rapidly. In the case lf/l > 0.8, the water mainly flows through a concentrated path connected by some fractures, resulting in it bypassing most oil regions, and thus the oil displacement efficiency decreases rapidly, similar to the water channeling.

Farinins are one of the oldest members of the gluten family in wheat and Aegilops species, and they influence dough properties. Here, we performed the first detailed molecular genetic study on farinin genes in Brachypodium distachyon L., the model species for Triticum aestivum. A total of 51 b-type farinin genes were cloned and characterized, including 27 functional and 24 non-functional pseudogenes from 14 different B. distachyon accessions. All genes were highly similar to those previously reported from wheat and Aegilops species. The identification of deduced amino acid sequences showed that b-type farinins across Triticeae genomes could be classified as b1-, b2-, b3-, and b4-type farinins; however, B. distachyon had only b3- and b4-type farinins. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) revealed that farinin genes are transcribed into mRNA in B. distachyon at much lower levels than in Triticeae, despite the presence of cis-acting elements in promoter regions. Phylogenetic analysis suggested that Brachypodium farinins may have closer relationships with common wheat and further confirmed four different types of b-type farinins in Triticeae and Brachypodium genomes, corresponding to b1, b2, b3 (group 1), and b4 (group 2). A putative evolutionary origin model of farinin genes in Brachypodium, Triticum, and the related species suggests that all b-type farinins diverged from their common ancestor ~3.2 million years ago (MYA). The b3 and b4 types could be considered older in the farinin family. The results explain the loss of b1- and b2-type farinin alleles in Brachypodium.

Methane hydrate dissociation in sediment may lead to geological hazards such as marine landslide, collapse of wellbore. The physical mechanisms, especially on the evolution of sediment damage, are not very clear sediment though some numerical simulations were presented based on conventional landslide. A failure form, namely layered fracture in sediment, was observed in experiments during hydrate dissociation, It was a gap tilled with gas and water formed from continuous sediment by the gas and water expansion. A large laterally distributed layered fracture in seabed is a potential mechanism for marine landslide formation due to the very small shear strength in the fracture. This issue was analyzed based on dimensionless method and a two-phase mathematical model. The extension of the method and results to relate the engineering problem were discussed also. A mathematical model for studying the initiation and expansion of layered fracture was presented first by decoupling the expansion of hydrate dissociation front, gas seepage, and the movement of soil layer. Then the critical condition for the initiation of layered fracture was obtained and the thickness expansion of the layered fracture was numerically analyzed. The results could be used to evaluate the development of layered fractures under the condition of different hydrate recovery methods and geo-mechanical properties of hydrate formations in the future and will be extended to the study on the mechanism of marine landslide. (C) 2015 Elsevier B.V. All rights reserved

Spatial distribution of gas hydrate dissociation is essential in analyzing gas recovery and related potential hazards. This work develops a 1D model for predicting the spatial distribution of gas hydrate dissociation under the combination of depressurization and heating in the clay-silty sediments. Without assuming a discontinuous interface and a sudden decrease of pressure, the sediment is divided into a dissociated zone, a dissociating zone, and an undissociated zone. The dissociating zone is further separated into a heating subzone and a non-heating subzone. This work finds that (i) the thicknesses of the dissociating zone and the heating subzone as well as the propagation distance of the hydrate dissociation front are all linear with the square root of time, and the square root of hydrate dissociation time at any location is also linear with the distance between the location and the production well; (ii) the expansion velocity of the dissociating zone is about ninety times faster than that of the heating subzone, and a higher absolute permeability causes a faster expansion velocity of the dissociating zone, but barely affects the expansion velocity of the heating subzone; and (iii) the thickness of the heating subzone is less than 5% of the thickness of the dissociating zone in the latter stage of the hydrate dissociation process.

Due to the intrinsic nonlinear characteristics and complex structure of the high-speed catenary system, a modelling method is proposed based on the analytical expressions of nonlinear cable and truss elements. The calculation procedure for solving the initial equilibrium state is proposed based on the Newton–Raphson iteration method. The deformed configuration of the catenary system as well as the initial length of each wire can be calculated. Its accuracy and validity of computing the initial equilibrium state are verified by comparison with the separate model method, absolute nodal coordinate formulation and other methods in the previous literatures. Then, the proposed model is combined with a lumped pantograph model and a dynamic simulation procedure is proposed. The accuracy is guaranteed by the multiple iterative calculations in each time step. The dynamic performance of the proposed model is validated by comparison with EN 50318, the results of the finite element method software and SIEMENS simulati...

Methane hydrate (MH) is a new energy resource in the 21(st) century. But the dissociation of MH from sediments during the MH exploration or oil/gas exploration under a hydrate layer accompanied by the softening of soils and formation of excess pore gas pressure may lead to ground failures and environmental disasters. In this study, experiments on modeling the weakening and failure of the sediment by heat-induced dissociation of tetrahydrofuran (THF) hydrate were presented. The failure mode of gas outburst was observed. Gas outbursts is a process where gas and soils in hydrate-dissociation zone burst out after the continuous skeleton of over-layer is fractured during the expansion of the dissociation zone and the formation of gas zone and excess pore gas pressure. An analytical method is presented by decoupling heat transfer and soil deformation. The geometrical and mechanical similarities for gas outburst are obtained. An empirical criterion for the occurrence of outburst is proposed using the theory of thermal conduction, rigid plastic mechanics, and the experimental data. Copyright (c) 2015 John Wiley & Sons, Ltd.

Due to its long-span structure and large flexibility, an electrified railway catenary is very sensitive to environmental wind load, especially the time-varying stochastic wind, which may lead to a strong forced vibration of contact line and deteriorate the current collection quality of the pantograph–catenary system. In this paper, in order to study the wind-induced vibration behavior of railway catenary, a nonlinear finite element procedure is implemented to construct the model of catenary, which can properly describe the large nonlinear deformation and the nonsmooth nonlinearity of dropper. The spatial stochastic wind field is developed considering the fluctuating winds in along-wind, vertical-wind, and cross-wind directions. Using the empirical spectra suggested by Kaimal, Panofsky, and Tieleman, the fluctuating wind velocities in three directions are generated considering the temporal and spatial correlations. Based on fluid-induced vibration theory, the model of fluctuating forces acting on catenary are developed considering the spatial characteristics of catenary. The time- and frequency-domain analyses are conducted to study the wind-induced vibration behavior with different angles of wind deflection, different angles of attack, as well as different geometries of catenary. The effect of spatial wind load on contact force of pantograph–catenary system is also investigated.

Marine landslide due to gas hydrate dissociation is a kind of potential heavy hazards. Numerical simulation was processed to investigate the deformation, landslide and effects of main factors on the critical scale of dissociation zone to induce marine landslides during/after dissociation of gas hydrate. A simple method for analyzing the critical scale was presented based on the limit equilibrium method. It is shown that the maximum settlement is located near the upper side of the dissociation zone. The soil near the lower side of the dissociation zone uplifts. There is a critical scale of dissociation zone over which landslide will occur under given conditions. Expansion modes of the dissociation zone have obvious effects on the critical scale.

Auditory verbal hallucinations (AVHs) which are the core psychopathology symptoms in schizophrenia patients cause amounts of distress, functional disability and behavioral dys-control. However, the neural mechanism with the onset of AVHs in schizophrenia remains unclear. In the present study, we recruited 30 schizophrenia patients with AVHs, 20 schizophrenia patients with non-AVHs (nAVHs), and 50 healthy controls. Structure magnetic resonance imaging was obtained, and voxel-based morphometry (VBM) was used to analyse the gray matter volume (GMV) in the three groups. We found that the GMV of anterior cingulate cortex (ACC), left superior temporal gyrus (STG), and left middle temporal gyrus (MTG) significantly decreased in schizophrenia patients compared to healthy controls. In addition, the left STG with significantly decreased volume was found in nAVHs compared to AVHs, but no significant changes of GMV in ACC and left MTG were found between AVHs and nAVHs. Our current study identified the abnormal GMV of the left STG in schizophrenia patients with AVHs. Our findings further supported the view that, whilst mild reduced GMV of the left STG might still enable the emergence of AVHs, more severe alterations may prevent the occurrence of AVHs experience.

Effects of heat softening on the initiation of slide surface (shear banding) in clayey slopes during fast deformation were discussed. Controlling equations considering heat, pore pressure and mechanical movement were presented. By perturbation method, the instability condition of localized zone (i.e. criterion for initiation of shear banding) for thermal related soils, such as clayey slope, was obtained. It is shown that slide surface initiates once the thermal-softening effects overcome the strain-hardening effects whether it is adiabatic or not. Without strain hardening effects, strain rate hardening obviously plays a role in initiation of shear band. During initiating process, heat is trapped inside the shear band, which leads rapidly to a pore pressure increase and fast loss of strength. The localized shear strain is concentrated in a narrow zone with a width of several centimeters at most and increases fast. This zone forms the sliding surface. Temperature can increase more than 2°C, pore pressure can increase 160% in about 0.1s inside this zone. These changes cause the fast decrease in friction-coefficient by about 36% over the initial value. That is how shear band initiated and developed in clayey slopes.

Taking the conglomerate from Xinjiang Oilfield as study object, the porosity distribution characteristics of the conglomerate were analyzed with CT scanning; through the online monitoring of the water and polymer flooding process in a conglomerate core using an CT scanning system, the saturation profile along the core and the CT reconstructed images of core section during the displacing process were obtained; oil displacement mechanism was analyzed according to a new characterization parameter, “oil saturation frequency distribution”. The results show that the conglomerate has strong heterogeneity, resulting in “dominant channels”, and in turn ineffective water circulation and low water flooding oil recovery, moreover, the oil in high oil saturation area is produced first. In polymer flooding, the oil in high and medium oil saturation areas can be produced but the oil in low oil saturation areas still cannot be produced. Oil produced in the subsequent water flooding is still mainly from the high oil saturation areas. For conglomerate reservoirs, previous water flooding should reach as high water cut as possible so as to strengthen the slug effect of the polymer. Meanwhile the injection volume of polymer should be reduced, and a subsequent water flooding should be used to push the polymer slug to produce oil. Key words: conglomerate, CT scanning, water flooding, polymer flooding, oil saturation, profile along the core, frequency distribution

Cognitive Radio (CR) is proposed to overcome the problem of spectrum underutilization and congestion caused by the increasing demand of wireless services and applications. It is still a challenge to improve the spectrum efficiency of the secondary network for Secondary (unlicensed) Users (SUs) and avoid imposing interference to the Primary (licensed) Users (PUs). In this paper, we propose a joint power control and spectrum access scheme for the CR network. By addressing the power allocation problem and exploiting a Dynamic Spectrum Access (DSA) scheme (which is based on the power allocation and also aims at improving the secondary network throughput) from a cooperative-game perspective, our joint scheme can improve the throughput of the secondary network and guarantee the SUs׳ fairness, without imposing overlarge interference to the PUs. Numerical results reflect that, compared with previous studies, our joint power control and spectrum access scheme presents advantages in comprehensive performance (e.g., spectrum efficiency, fairness and throughput). Beyond a theoretical framework, we solve the optimization problem with the Differential Evolution (DE) algorithm which is more feasible to be implemented in practice.

Fibroblast-like synoviocytes (FLSs) play an important role in the pathogenesis of rheumatoid arthritis (RA). This study was conducted to explore the role of microRNA (miR)-192 in the regulation of the biology of RA-FLSs. The expression of miR-192 in RA and healthy synovial tissues was measured. The effects of overexpression of miR-192 on RA-FLS proliferation and apoptosis were investigated. Luciferase reporter assay and Western blot analysis were performed to identify direct target genes of miR-192. RA synovial tissues had significantly lower levels of miR-192 than healthy controls (P = 0.004). Moreover, miR-192 levels were 2.9-fold lower in RA-FLSs relative to normal human FLSs (P

VanDerPol oscillator behavior under the excitation of weak signal is researched in this paper, the methods of phase space reconstruction analysis can realized the chaotic model, it help us to figure out the parameters of chaotic system. We give ways of how to select the parameters of time delay value and embedding dimension in phase space reconstruction, we select the VanDerPol oscillator to analysis the different parameters influence on chaotic system, the numeric analysis prove that if select appropriate embedding dimension and delay time, the remodeling results can reflect the dynamic characteristics of the original signal.

It is of great importance for the estimation of reserve, distribution and feasibility of exploitation to study the formation dynamics of natural gas hydrate. Appropriate low temperature and high pressure are the two key parameters for the formation of natural gas hydrate besides gas supply and migration pathway. Meanwhile, the characteristics of the sediment and the existence of the Chloridionand Sulfate ions are also important for the formation of natural gas hydrate. To analyze correctly the formation of natural gas hydrate in some area, we should first obtain detailed historical data of geology, physics and mechanics by geological survey and then build the proper mathematical model. In this paper, summary on several areas has been first processed based on the enough relative data. Next the general and special characteristics of the formation in these areas have been discussed. Then the previous mathematical models for the formation dynamics of natural gas hydrate have been reviewed. The suggestions about the development of the mathematical model for the formation and the main parameter should be focused in the future exploration have been presented.

Gas hydrate dissociation can cause the instability of marine stratums. The geological hazards and environmental effects relative to gas hydrate exploitation have attracted great concerns. In this paper, the studies on the hazards (Marine landslide, debris flow, damage of structures etc.) and environmental effects are summarized. The main factors of hydrate dissociation are discussed. Six typical large marine slides are introduced at beginning and, then the studies on the mechanism and failure critition are reviewed. The layered fracture and gas outburst and the instability of marine structures due to gas hydrate dissociation are illustrated and the critical conditions are discussed. The monitoring technologies and the data processing methods during gas hydrate dissociation are introduced. The studies on the mechanical and physical propertis of gas-hydrate-bearing sediment closly related hazards are summarized also. Finally, the problems and future study topics on the safety relative to gas hydrate exploitation are presented.

Active control of pantograph could be performed to decrease the fluctuation in pantograph-catenary contact force (PCCF) in high-speed railway. However, it is difficult to obtain the states of the pantograph when state feedback control is implemented. And the measurements may randomly miss due to the severe operation condition of the pantograph-catenary system (PCS). To address this issue, a robust recursive state estimation method (RRSEM) is presented is this paper. First, a nonlinear model of double-pantograph-catenary system (DPCS) is established by means of the finite element method. Then, the RRSEM is introduced to estimate the pantograph states based on the dynamic model. The simulation results indicate that the proposed RRSEM is able to accurately estimate the states of the leading pantograph (LP) and the trailing pantograph (TP).

Waxy starch has an important influence on the qualities of breads. Generally, grain weight and yield in waxy wheat (Triticum aestivum L.) are significantly lower than in bread wheat. In this study, we performed the first proteomic and phosphoproteomic analyses of starch granule-binding proteins by comparing the waxy wheat cultivar Shannong 119 and the bread wheat cultivar Nongda 5181. These results indicate that reduced amylose content does not affect amylopectin synthesis, but it causes significant reduction of total starch biosynthesis, grain size, weight and grain yield. Two-dimensional differential in-gel electrophoresis identified 40 differentially expressed protein (DEP) spots in waxy and non-waxy wheats, which belonged mainly to starch synthase (SS) I, SS IIa and granule-bound SS I. Most DEPs involved in amylopectin synthesis showed a similar expression pattern during grain development, suggesting relatively independent amylose and amylopectin synthesis pathways. Phosphoproteome analysis of starch granule-binding proteins, using TiO2 microcolumns and LC-MS/MS, showed that the total number of phosphoproteins and their phosphorylation levels in ND5181 were significantly higher than in SN119, but proteins controlling amylopectin synthesis had similar phosphorylation levels. Our results revealed the lack of amylose did not affect the expression and phosphorylation of the starch granule-binding proteins involved in amylopectin biosynthesis.

A multidisciplinary integrated design concept is firstly applied to synthesize optimum pantograph. Three disciplines are involved in the integrated design of the high-speed pantograph. They are the kinematics, the dynamics and the control. In this study, the objective function of the kinematics involves the curve of pan-head to guarantee the kinematics stability. Genetic algorithm is proposed to get the optimum design parameters of pantograph. Based on design parameters of high-speed pantograph, the lumped mass model is deduced. So, the dynamic contact force is obtained. When a high-seed train is running, the contact pressure of the pantograph-catenary is changed. So, the objective function of the active control is to minimize the contact pressure fluctuation by using optimal control. The integrated design pantograph not only satisfies the kinematics, the dynamics and the control constraints but also has synthesized optimum pantograph. The results lay a theoretical foundation to develop the new high-speed pantograph.

Supplemental Digital Content is available in the text, Structural abnormalities in schizophrenia (SZ) patients have been well documented with structural magnetic resonance imaging (MRI) data using voxel-based morphometry (VBM) and region of interest (ROI) analyses. However, these analyses can only detect group-wise differences and thus, have a poor predictive value for individuals. In the present study, we applied a machine learning method that combined support vector machine (SVM) with recursive feature elimination (RFE) to discriminate SZ patients from normal controls (NCs) using their structural MRI data. We first employed both VBM and ROI analyses to compare gray matter volume (GMV) and white matter volume (WMV) between 41 SZ patients and 42 age- and sex-matched NCs. The method of SVM combined with RFE was used to discriminate SZ patients from NCs using significant between-group differences in both GMV and WMV as input features. We found that SZ patients showed GM and WM abnormalities in several brain structures primarily involved in the emotion, memory, and visual systems. An SVM with a RFE classifier using the significant structural abnormalities identified by the VBM analysis as input features achieved the best performance (an accuracy of 88.4%, a sensitivity of 91.9%, and a specificity of 84.4%) in the discriminative analyses of SZ patients. These results suggested that distinct neuroanatomical profiles associated with SZ patients might provide a potential biomarker for disease diagnosis, and machine-learning methods can reveal neurobiological mechanisms in psychiatric diseases.

Low molecular weight glutenin subunit is one of the important quality elements in wheat (Triticum aestivum L.). Although considerable allelic variation has been identified, the functional properties of individual alleles at Glu-3 loci are less studied. In this work, we performed the first comprehensive study on the molecular characteristics and functional properties of the Glu-B3h gene using the wheat cultivar CB037B and its Glu-B3 deletion line CB037C. The results showed that the Glu-B3h deletion had no significant effects on plant morphological or yield traits, but resulted in a clear reduction in protein body number and size and main quality parameters, including inferior mixing property, dough strength, loaf volume and score. Molecular characterization showed that the Glu-B3h gene consists of 1179 bp and its encoded B-subunit has a longer repetitive domain and an increased number of α-helices, as well as higher expression, which could contribute to superior flour quality. The SNP-based allele-specific PCR markers designed for the Glu-B3h gene were developed and validated with bread wheat holding various alleles at Glu-B3 locus, which could effectively distinguish the Glu-B3h gene from others at the Glu-B3 locus and have potential applications for wheat quality improvement through marker-assisted selection.

Three wheat glutenin near isogenic lines (NILs) CB037A, CB037B and CB037C were used to investigate their quality properties and the transcriptional expression profiles of PDI gene family during grain development. Our purpose is to understand the relationships between the dynamic expression of different PDI genes and glutenin allelic compositions related to gluten quality. The results showed that glutenin allelic variations had no significant effects on main agronomic traits and yield performance, but resulted in clear gluten quality changes. CB037B with 5+10 subunits had higher glutenin macropolymer (GMP) content and better breadmaking quality than CB037A with 2+12 while the lack of Glu-B3h encoding one abundant B-subunit in CB037C significantly reduced GMP content, dough strength and breadmaking quality. The dynamic expression patterns of eight protein disulfide isomerase (PDI) genes during grain development detected by quantitative real-time polymerase chain reaction (qRT-PCR) showed the close correlations between higher expression levels of PDI3-1, PDI5-1 and PDI8-1 and the presence of 5+10 subunits. Meanwhile, Glu-B3h silence resulted in significant decrease of expression levels of five PDI genes (PDI3-1, PDI5-1, PDI6-1, PDI7-2 and PDI8-1), suggesting the vital roles of certain PDI genes in glutenin and GMP synthesis and gluten quality formation.

To study the liquefaction potential of sand surrounding bucket foundations, centrifuge experiments were carried out. Results have shown that the sand layer around a bucket foundation softens or liquefies under vertical dynamic load when the load amplitude is over a critical value. The liquefaction potential decreased in horizontal direction from the side wall and in vertical direction from the surface of sand layer. The thickness of the completely liquefied sand layer increased with the increase of load amplitude. The affected area which has obvious liquefaction potential is almost the same for a given bucket under different load amplitudes.

It is difficult to obtain high quality samples of natural material covering a range of densities and degree of cementation, so study on the sample preparation techniques with similar mechanical properties of natural samples are very important. Experiments were carried out to study the effects of cementation of different materials on the mechanical properties of calcareous sand, e.g., the effects of contents and types of cementation materials on the strength and the characteristics of stress-strain. It is shown that Portland cement is a good cementation agent, compared to calcite and gypsum. The strength of calcareous sand increases with the increase of Portland cement content.

Mechanical properties of methane hydrate-bearing-sediments (MHBS) are basic parameters for safety analysis of hydrate exploration and exploitation. Young’s modulus, cohesion, and internal friction angle of hydrate-bearing sediments synthesized in laboratory, are investigated using tri-axial tests. Stress-strain curves and strength parameters are obtained and discussed for different compositions and different hydrate saturation, followed by empirical expressions related to the cohesion, internal friction angle, and modulus of MHBS. Almost all tested MHBS samples exhibit plastic failure. With the increase of total saturation of ice and methane hydrate (MH), the specimens’ internal friction angle decreases while the cohesion increases.

Rainfall is an important factor to trigger the slope failure such as landslides and debris flows. First, the relationship between rainfall duration with the initiation of debris flow and rainfall intensity was mainly studied by the series tests in a box model. Then, the rainfall induced responses of slopes and the initiation of slope failure were simulated by using the software FLAC2D based on the soil parameters in Weijia Gully, Beichuan County, Sichuan Province. The effects of the slope angle, rainfall intensity, soil parameters on the development of the stress, and pore pressure in the soil of the slope were analyzed. It indicates that largest displacements in the slope are mainly located near the toe. With the increase of the rainfall intensity, the effective stress in the slope decreases and the displacement increases.

This paper Analysis the VanDerPol-Duffing system movement perturb Ted by weak signal under Non-Gaussian noise environment. We educe out the threshold of chaotic movement of VanDerPol-Duffing non-linear system. It is found that the non-Gaussian color noise has little effect on the chaos character of this chaotic oscillator, well the values of parameters of the excitation weak sinusoidal signal appear much change of chaotic dynamic system. The tiny change to the amplitude and frequency of the excitation weak sinusoidal signal will induce the chaotic system behavior great differently, this character help us estimate parameters of weak sinusoidal signal. The simulation result shows that the Non-Gaussian noise has little effect on the non-linear system movement when it is on chaotic state, while much effect on for Non-Gaussian noise. The conclusions appear that the chaotic oscillator is immune to zero mean non-Gaussian color noise for weak sinusoidal signal frequency and amplitude parameter estimate.

A model for the elastic modulus of hydrate-bearing sediment (HBS) is presented considering the variation of the hydrate saturation and hydrate occurrence mode. The model is based on the classical series and parallel modes, introducing a parameter of statistical force transfer paths among particles in HBS. Macro-triaxial compression tests and micro X-ray computed tomography (CT) observations of HBS in the gas-saturated formation mode were conducted. The applicability of the model was checked through the comparison between tests and theoretical results.

Landslides and collapses occurred during the May 12th earthquake in Wenchuan County. Most of these landslides and collapses were caused by shear bands. Shear band triggers instability on mountain slopes, resulting in debris flow, landslides, or collapse. According to experimental results, there was only one shear band forming in the soil layer prior to the initiation of debris flow under shear load, although several fine shear bands appeared. The development of shear bands in saturated soils is numerically investigated in this paper using the in situ soil from the Weijia Gully, Beichuan County. The evolution of shear banding from several finite amplitude disturbances (FADs) in pore pressure has been studied. The numerical analysis revealed that the FADs evolved into a fully developed shear band. It is shown that the shear banding process consists of two stages: inhomogeneous shearing and true shear banding.

Rainfall is an important factor to trigger the debris flow. Numerical simulation on the responses of slopes and the initiation of debris flow under rainfall was processed by using the software FLAC2D based on the soil parameters in Weijia Gully, Beichuan County, Sichuan Province, China. The effects of the slope angle, rainfall intensity, soil parameters on the developments of the stress and pore pressure and deformation of the slope were studied. It indicates that large displacements of the slope are mainly located near the slope toe. With the increase of the rainfall intensity the stability of the slope decreases and so the debris-flow is easy to occur.

Hydrate dissociation in marine deposits may cause large disasters.Experiments are carried out to study the failure conditions and modes caused by the dissociation of hydrate.A rectangular model box and a cylindrical model box are designed to simulate the two-dimensional and one-dimensional conditions respectively.It is shown that kinds of failure modes,including slowly sliding and settlement,layered destruction and burst,occur with the thermal dissociation of hydrate happened fast or slow and for different hydrate deposit and cover deposit(such as the heterogeneity of the deposit,permeability of the cover layer).Each kind of these failures is a severe threat to engineering.