用手写记笔记

<正>Many students have given up taking class notes by hand.Instead,they type on laptop or tablet computers.But scientists say that that method is less effective.If you need to remember something,write it.Writing notes by hand is much better for long-term memory of ideas,or conceptual information.许多学生做笔记不用手写,而是记在笔记本或者平板电脑上。但是科学家们表示,这样记笔记效果不佳。如果你需要记住一些东     

如何提高学习成绩

<正>Are you feeling down about your grades?It is easy to get the blues when you receive low scores on a big test or small quizzes,but you can’t let poor performance get you down.There is always time to make things better.你对自己的成绩感到沮丧吗?当你在大考或小测验中得低分时,很容易闷闷不乐,但不能因为糟糕的表现就变得沮丧。你还有时间把事情做得更好。And there are always reasons to improve.If you fail a few tests,you can do better next time.Just don’t get down on yourself!     

利用改进的DDA进行边坡上落石运动的数值模拟

The reasonable design of protective structures to mitigate the hazards from rock fall depends on the knowledge of motion behaviors of falling stones,such as the falling paths,velocities,jump heights and distances.Numerical simulation is an effective way to gain such kind of knowledge,In this paper,the discontinuous deformation analysis (DDA) is applied to rock fall analysis.In order to obtain more reliable results,the following improvements and extensions are made on the original DDA.(1)Solve the problem of block expansions due to rigid body rotation error.(2) Add the function of modeling the drag resistance from air and plants so that the velocities of falling stones obtained by simulations are good enough in agreement with those by experiments in situ.(3)Add the capability to consider energy loss due to block collisions so that the jumping heights and distances obtained by simulations are good enough in agreement with thos by experiments even for the slope with very soft layer on its surface.One of application examples is presented to show that the extended DDA is very effective and useful in rock fall analysis.Therefore,the presented method is expected to be put into wide use in slop stability analysis.     

On the thermo-mechanical properties of unsaturated soils

The establishment of energy balance equation is necessary to study the thermo-mechanical properties of unsaturated soils.To solve this equation,the determination of two fundamental parameters as volumetric specific parameter and thermal conductivity coefficient is essential.In this paper,the effective thermal conductivity coefficient of dry soil grain is analyzed for soils with different compositions,and the thermo-mechanical properties of porous media with water and gas are studied by considering the soil water retention curve（SWRC）.Different methods,i.e.volumetric average method,self-consistent method,Hashin-Strikman method,are employed to calculate thermal conductivity coefficients,and a new method is proposed to determine the thermo-mechanical parameters.Comparison of the results obtained by different methods shows that the proposed method is in a good agreement with the experimental results and is suitable for describing the main properties of the thermo-mechanical behaviors of soils.The relationship between the SWRC and the seepage curve is further studied by the natural proportional rule.The characteristics of the SWRC,its differential coefficient and the seepage curve,are investigated by considering the physico-mechanical mechanism;the limit scopes of the indices of the SWRC and the seepage curve are also given.     

A Survey of the Residents''''Needs for Outdoor Activities

The Article is based on an on-the-spot investigation of the needs of the residents.Visits were made to obtainin-depth understanding about the patterns in the outdoor activities.Survey results are analysed from many respectssuch as landscaping,noise,living facilities,security and building space,in order to probe into the issue of how tocreate good outdoor environment for the residents in the planning of residential areas.     

Guidelines for Low-Cost,Energy-Efficient House in Iraq

The goal of this study is to determine specific guidelines for Iraqi architects to contribute to the design and composition of energy-efficient housing units within the limits of a normal budget, locally available materials and technologies. These units can provide comfort despite the current energy situation in Iraq. The study is based on a computer simulation for a reference building in Baghdad, which has been selected according to the urban conditions, building legislations, housing market and statistics. The final results displayed the main recommendations and the possibility to achieve up to 50% energy reduction with a pay-back period not exceeding two years in some cases. There are some measures that have big energy saving potential. Yet, some of the measures may require big investment or have some bad environmental impacts. Some other good measures are already being implemented.     

Studies on the key parameters in segmental lining design

The uniform ring model and the shell-spring model for segmental lining design are reviewed in this article.The former is the most promising means to reflect the real behavior of segmental lining,while the latter is the most popular means in practice due to its simplicity.To understand the relationship and the difference between these two models,both of them are applied to the engineering practice of Fuzhou Metro Line I,where the key parameters used in both models are described and compared.The effective ratio of bending rigidity η reflecting the relative stiffness between segmental lining and surrounding ground and the transfer ratio of bending moment ξ reflecting the relative stiffness between segment and joint,which are two key parameters used in the uniform ring model,are especially emphasized.The reasonable values for these two key parameters are calibrated by comparing the bending moments calculated from both two models.Through case studies,it is concluded that the effective ratio of bending rigidity η increases significantly with good soil properties,increases slightly with increasing overburden,and decreases slightly with increasing water head.Meanwhile,the transfer ratio of bending moment ξseems to only relate to the properties of segmental lining itself and has a minor relation with the ground conditions.These results could facilitate the design practice for Fuzhou Metro Line I,and could also provide some references to other projects with respect to similar scenarios.     

中国经济技术开发区建设的生态学理论研究

Introducing ecology and sustainable development concept into Development Zone planning has now been an unavoidable issue for us. The ecological urban planning must be based on the sustainable development theory. In the Development Zone construction, People are inclined to think that the city represents the most terrible aspects. If people do not underpin the relationship between human and the environment in a specific manner, this spiritual relationship will finally break down. The development of a city is a dynamic process, and it is impossible to get the urban planning done once and forever. Thus, enough space should be set aside for the sound development of a city.     

Effect of graph generation on slope stability analysis based on graph theory

Limit equilibrium method （LEM） and strength reduction method （SRM） are the most widely used methods for slope stability analysis. However, it can be noted that they both have some limitations in practical application. In the LEM, the constitutive model cannot be considered and many assumptions are needed between slices of soil/rock. The SRM requires iterative calculations and does not give the slip surface directly. A method for slope stability analysis based on the graph theory is recently developed to directly calculate the minimum safety factor and potential critical slip surface according to the stress results of numerical simulation. The method is based on current stress state and can overcome the disadvantages mentioned above in the two traditional methods. The influences of edge generation and mesh geometry on the position of slip surface and the safety factor of slope are studied, in which a new method for edge generation is proposed, and reasonable mesh size is suggested. The results of benchmark examples and a rock slope show good accuracy and efficiency of the presented method.     

Feilden Clegg Bradley 建筑师事务所,英国

Design Concept The development aims to utilise the strength of a monocoque structural approach to generate both economic manufacturing and constructional solutions whilst also generating greater three dimensional spatial opportunities. Courtyard units which maximise use of internal and external spaces are an effective solution to high density urban living. The design of the dwellings maximises daylight and natural ventilation.This helps to lower electricity loads, and reduces the need for heating and cooling,which is further enhanced through good insulation, efficiency of the building form and thermal mass.