Damage Constitutive Equation and Experiment of Layered Rock

The microcosmical study on many speciments of sedimentary rock by SEM and petrography theory show that rock is formed of microcrystalline and micropore with all kinds of forms.Therefrom the microstructure model of rock is established.Further the three dimensional nonlinear damage constitutive equation and damage evolution equation of layered rock including respective process of damage evolution,mechanical parameter,effective stresses,and unequal biaxial stress in different rocks are derived.The results of the experiment indicate that the theoretical curve is fairly close to the experimental curve.     

Solution for One-Dimensional Contaminant Diffusion in Layered Clayey Soils Using Laplace Transforms

Contaminant diffusion in layered soil is very complex. The diffusion process is simplified as a one-dimensional diffusion mode. The Laplace transformation and Laplace numerical inverse transformation are adopted. The proposed solution can be degraded to a single layer case. The obtained results are well consistent with those obtained by the classic theory. The correctness of the presented solution is verified by comparing the calculation results with the results generated by existing numerical software. One case study is conducted and the calculation results have a good agreement with measured data, which prove the reliability of the proposed method. The presented method can be used to solve more complex boundary conditions of contaminant migration.     

基于投入产出模型的四川郫都传统农业轮作模式的可持续性评价

为了说明四川省郫都区轮作模式的可持续性,及其潜在的经济及环保价值。基于投入产出理论,对郫都区5种典型轮作种植模式构建价值投入产出表与投入产出系数表。通过传统轮作模式与现代连作模式的比较,以及传统模式之间的比较,直观地对郫都区现有的轮作模式进行可持续性分析和评价。结果表明,由于传统的轮作模式符合作物自然生长规律,对农药和化肥的依赖性远低于现代连作模式,并较好地保持了农作物的生物多样性,但其单位面积产出低于连作模式。对稻蒜、稻韭、稻菜、稻姜和稻萝5种传统的轮作模式进行投入产出分析发现,5种模式单个产品投入和产出占比几乎一致,说明郫都区这种水旱轮作模式是一个有机整体,统一而又协调。要使传统的轮作模式得以发扬与传承,郫都区应打好天府水源地有机绿色农产品品牌,政府在相关政策方面应予以相应的鼓励和支持。     

The Micro/Macro Mechanic Analysis of PD3 Pearlitic Steel with Layered Microstructures

A micro/macroscopic analysis of PD3 pearlitic steel with layered microstructure is carried on.Based on the compatibilit conditions of stress and strain at the interface between two layers as well as the mixed law of composites,constitutive equations of an effective homogeneous inclusion are obtained.combining these equations with the K B W self consistent model,the micro macroscopic transition has been estabilished.It turns out that the analysis is capable of determining the overall responses of materials as well as local stress evolution in microstructure under monotonic and cyclic loading.It is found that stress in the thin cementite layer is very high.This is caused by intersification of the local plastic flow of the soft ferrite layer in which more loading is transferred cycle by cycle to the hard phase.Furthermore,a strength dimension law that the strength is inversely proportional to the square root of the layer thickness is developed to explain the high strength of the cementite layer.     

浅论实现基于MapX的灌溉信息系统的关键技术

现代化的灌溉用水管理是实现农业高效用水的重要措施之一,它可实现灌溉水资源的合理配置和灌溉系统的优化调度,达到节水增产目的,使有限的水资源获得最大的效益。采用手工方式进行灌溉用水管理,难以及时提供水资源利用最优化方案,因此急需研制出具有网络通信功能的可视化操作界面的灌溉信息管理系统,为灌区水资源评价和利用、规划等工作奠定良好的数据基础。GIS不仅具有强大的空间数据管理功能,还具有丰富的多元地学数据分析处理能力和直观的图形显示效果,因此利用GIS进行灌区的管理与建设将会有效提高灌区的工作效率和经济效益。笔者在实践调研的基础上,根据灌溉信息管理系统的功能规划及结构设计,利用MapX组件工具开发了陕西省冯家山灌区灌溉信息系统,对提高灌溉用水的管理效率进行了实例尝试,并着重对下列关键技术的运用进行了实践与思考：（1）阐述了利用可视化编程工具结合数据库管理技术、地理信息系统组件技术、网络通信技术等进行系统开发的过程;（2）着重介绍了基于MapX组件的空间数据库的建立与关联技术、灌溉管理信息的网络通信实现技术;（3）最后对在灌溉管理工作中运用GIS技术进行科学管理等相关问题进行了有益的探讨。     

Stresses and Deformations Independent of Polar Angle in Anisotropic Layered Cylindrical Shells

In this paper authors present a method to analyse stresses and deformations independent of polar angle in anisotropic layered cylindrical shells.An ordinary differential equation concerning deflection,its general solution and formula for analyzing stresses and deformation in fiber wind layered cylindrical shells are deduced.     

Technology of Developing CAI Courseware Based on Web

This paper introduces specificities of CAI courseware based on network,the configuration and connection of courseware server, compares several technologies to develop CAI courseware based on network, discusses technical key points to develop courseware based on campus network.     

A Cosserat Theory-based Numerical Simulation of an Underground Cavern in Layered Rock Mass

Conventional equivalent continuum theory poorly interprets the bending deformations and damage phenomena encountered in rock engineering because the theory ignores the influence of gradient stress.The influence of the bending effect on deformation characteristics of the media has been considered in Cosserat continuum theory which introduces the concepts of coupled stress and bending curvature.The basic principle of Cosserat medium theory and its expanded constitutive model were introduced firstly.Next,a numerical simulation of an underground cavern was carried out using FLAC software.After this,the results of the Cosserat model and explicit joint model were compared.The simulation results not only displayed the bending deformation of layered rock mass well,but also demonstrated the validity and superiority of the Cosserat expanded model.     

One Dimensional Consolidation Analysis of Layered Clay Soils Exhibiting Rheological Characteristics

The rheological characteristics of clay soils were described by Merchant mode. The governing equation for consolidation of layered clay soils exhibiting rheological characteristics was solved using the finite element method. Matrix formulation was derived by Galerkin's weighting residual method. The proposed FE procedure was encoded in a program. The presented formulation and program code were examined by using the analytical results of two simplified problems, a one layer clay soil exhibiting rheological characteristics and a double layer elastic clay soil. The comparison shows that the numerical results agree well with those of analytical results. A three layer clay soil exhibiting rheological characteristics was used to analyze influence of rheological characteristics and its parameter η 1 on different layers at different time. The results show that consolidation of clay exhibiting rheological characteristics is slower than that of clay exhibiting elastic characteristics. The phenomenon becomes more obvious over time and the distance between the clay and the pervious plane increases. Difference between the pore pressure dissipation of rheological clay and that of elastic clay reaches its climax when the consolidation degree of clay is in the range from 80% to 90%. Difference between the consolidation degree of rheological clay and that of elastic clay becomes larger and the influence time is earlier with higher creep parameter η 1.     

Networking Database Technology Based on CORBA

This paper firstly introduces a new technology: CORBA by comparing several technologies of Web accessing database, then a few main features were briefly described. On this basis, the CORBA working function was analyzed. At last, an example of successful CORBA based network database was presented.     

Database Technology in Wireless Sensor Networks

As a result of combination of microsensor technology,low power computing and wireless networking,wireless sensor networks become an active branch in scientific territory of computer science at the moment.The recent reserch work on data management of wireless sensor networks is mainly introduced. In order to achieve high performance of the data-center network system,and supply an effective sensor database administration processing system in the interest of observing person or consumer,Separately proposed valid settlement schemes for the two key problems in database technology: data model and query processing.     

Axisymmetric Loaded Elastic Circular Plate on Multi Layered Soil

An analytical solution of the elastic circular plate on multi layered soil can be obtained by using the transfer matrix solutions for displacements and stresses of multi layered soil. This solution is based on the continuity of vertical displacements and the smooth contact conditions between a multi layered soil surface and the elastic circular plate. Numerical calculation and analysis are carried out by the computer program compiled for this purpose. The numerical results show that the rigidity of the elastic circular plate greatly influences the displacement of the circular plate and the normal stresses under the center of the circular plate.     

An Elastic Theory Approach and Parametric Analysis of Pile Group in Layered Soils

Based on the technique proposed by Muki & Sternberg, a rigorous analytical method for calculating the interaction factor between two piles with different lengths, diameters and properties is presented. The pile group in layered soils is calculated by using the principle of superposition. The validity of the presented method has been verified through comparing with those from other existing solutions. A parametric analysis is made to study the pile group settlement and the loads shared by the individual pile. The proposed interaction factors of pile-pile can consider the strengthening effect of intervening piles. The proposed method can be used to analyze the large pile group.     

An Equivalent Shear Displacement Method of Single Capped Pile in Layered Soil

Based on the interaction of single pile, cap and soil, the load transfer matrixes of single pile and soil were proposed to establish an equivalent shear displacement method of single capped pile in layered soil. With the compatibility of displacement at the interface between the pile and the soil, equilibrium equations of pile and soil could be derived. With the increase of the total load on the pile cap, the lateral friction at the interface of the pile and the soil becomes so large that the occurrence of the sliding takes place. While there is little sliding at the interface between the soil under cap and the soil outside of the cap because of the less lateral friction, which gives rives to less settlement of the soil outside of the cap. Eventually, the results of the finite element method, existing theoretical method and the model tests were compared with those from the analytical method and were found to be in good agreement. The increase of the ratio of length to diameter does not infinitely enlarge the overall stiffness of the single capped pile, because the pile cap would afford part of the loading all the time.     

Research Methods of Brain-computer Interface Technology

Brain computer interface(BCI) is an EEG based communication and control system between human and computer or other electric devices, which does not depend on the brain's normal output channels of peripheral nerves and muscles. It is a novel kind of human interface, may have applications in rehabilitation, control and other fields. The developming speed of brain computer research in recent years is high. Methods of how to use P300, SSVEP, ERS/ERD, SCP, spontaneous EEG and implanted electrode to realize BCI are introduced. Characteristic and limitation of different methods are discussed. Status, problems and application prospects of BCI technology are also included.     

Discussion about MIS Development Model

This paper analyzes and summarizes the main problem in developing Management Information System (MIS). On this basis, it presents a new model of MIS development. In this model, the authors emphasize and discuss the importance and conformation of independent system application platform. The final purpose of this model lies in making the users to maintain database, reconstruct application system and develop new application conveniently.     

食品工艺学实践教学模式探讨

食品工艺学实践教学是食品科学与工程专业培养高素质人才的基础,采用基础实验、综合实验和理论知识提升的递进式模式,探讨了不同实践教学阶段采取的相应方法和手段,取得了良好的教学效果。     

Time Domain BEM for Wave Propagation Problems in Layered or Anisotropic Media and Its Application in Engineering

The dynamic response of an underground powerhouse under seismic waves is studied by time domain BEM for anisotropic media. The responses of displacements and stresses are evaluated. The effects of angle and frequency of incident waves and the degree of media anisotropy on dynamic response of the underground structure are analyzed in detail. Some important findings for engineering are obtained.     

高职院校肉制品加工技术实践教学模式的构建研究

肉制品加工技术是一门实践性和应用性很强的学科,通过构建实践教学模式,实践教学的效果得到了很大提高,使学生实践动手能力大大加强,理论与实际结合取得了很好的学习效果,为学生的就业打下坚实的基础。