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1.
A.  J.  Dalton 《英语沙龙》2010,(7):14-15
Every year, it costs British students more and more to attend university. Students are graduating with larger and larger debts. So is a university degree really worth it?  相似文献   

2.
READINGS     
何乐 《今日中学生》2011,(13):22-23
Early rising is helpful more than one way.First,it helps us to have good health.The air is never so fresh asthat in the early morning.Taking fresh air and doing morning exercisesmake a good start for the day.  相似文献   

3.
The Wind     
The sun can make the wind blow! The sun can make air move across the earth in a wind.First, sunshine makes the earth warm. Then when the air is close to the earth, the earth makes it warm. As the air gets warmer, it also gets lighter. It goes up while cooler air moves in to fill its place. This is like a turning wheel(车轮)--as one part is going up, another part is moving along the ground.The warm air grows cool when it is high above the earth, and then it comes down again. Once more the ear…  相似文献   

4.
Knowledge is power. But we must remem-ber one other thing. A strong mind needs a strong body in order to make it most useful. There are many good exercises. They are helpful and healthful. Some of them may be taken in the room during raining weather. These exercises, however, are never as helpful as those taken out of doors in pure fresh air. It’s because in fresh air more oxygen is taken into our sys-tems and more wastes are given off. The air in the house does not keep fresh very long. Bu…  相似文献   

5.
Two numerical simulations were performed to investigate the protective effect of the foam cladding. One simulation is based on a previous experimental study, which is a ballistic pendulum with and without a foam cladding subjected to close-range blast loading. The other model is a steel beam with and without a foam cladding under blast loading. The overpressure due to the blast event can be calculated by the empirical function ConWep or by an arbitrary Lagrangian-Eulerian (ALE) coupling model. The first approach is relatively simple and widely used. The second approach can model the propagation of the blast wave in the air and the interaction between the air and the solid. It is found that the pendulum with the foam cladding always swings to a larger rotation angel compared to a bare pendulum. However, the steel beam with an appropriate foam cladding has a smaller deflection compared to the bare beam without a foam cladding. It is concluded that the protective effect of the foam cladding depends on the properties of the foam and the protected structure.  相似文献   

6.
Two numerical simulations were performed to investigate the protective effect of the foam cladding. One simulation is based on a previous experimental study, which is a ballistic pendulum with and without a foam cladding subjected to close-range blast loading. The other model is a steel beam with and without a foam cladding under blast loading. The overpressure due to the blast event can be calculated by the empirical function ConWep or by an arbitrary Lagrangian-Eulerian (ALE) coupling model. The first approach is relatively simple and widely used. The second approach can model the propagation of the blast wave in the air and the interaction between the air and the solid. It is found that the pendulum with the foam cladding always swings to a larger rotation angel compared to a bare pendulum. However, the steel beam with an appropriate foam cladding has a smaller deflection compared to the bare beam without a foam cladding. It is concluded that the protective effect of the foam cladding depends on the properties of the foam and the protected structure.  相似文献   

7.
Selection of air conditioning (AC) cold/heat sources generally concerns about certain aspects and cannot reveal the whole profile of the problems. Grey relation analysis (GRA) is a data processing method to categorize the correlation extent of compared sequences and a certain reference sequence in a system with uncertain information. It is applied to evaluating and selecting AC cold/heat sources from four main aspects, which are technology, economy, reliability, and operation and management. Case study shows that the result for selecting AC cold/heat sources with the GRA method can be more reasonable and convincible. Thus it offers a new approach for designers in heating, ventilating and air conditioning field to compare and evaluate different AC cold/heat sources.  相似文献   

8.
With the emergence of a economic globalization and China’s enter into WTO,China has witnessed a sharp increase in foreign investment and plenty Chinese firms into the international market.Business negotiation is the most common phenomenon in business life and international trade,so understanding the behaviors of the negotiators is a vital presupposition for successful negotiations to obtain a mutually satisfactory agreement.This is still more important if the cultural backgrounds of the parties involved are different,for example,between Chinese and American parties.In fact,the larger the cultural differences,the greater barriers to communication,and the more likely misinterpretation of the negotiation.Intercultural understanding is the foundation and basic for long-term mutually beneficial cooperation,therefore,to negotiate triumphantly,cultural differences between the parties concerned must be identified and solved.This article will expound negotiation behaviors between China and America.  相似文献   

9.
INTRODUCTION The primary function of an intake system is firstly to efficiently channel fresh air to the engine,and secondly to minimize intake noise emissions.There are a number of current approaches for devel-oping a more realistic method to improve intake sys-tem design.The objectives include more effective silencing performance to meet increasingly severe legislative targets for reduced noise on the one hand,with optimized engine performance and fuel economy accompanied by improvements…  相似文献   

10.
SUMMARY Critics of large digitization projects say that the quality of information available to students is being lost in a rush to increase its quantity. But in reality the larger amounts of material mean that it is more likely students can find appropriate and relevant documents. What is happening is that people react to the large quantities of material on the Web and the power of the search engines by seeking the right places to read, rather than being limited to a few items by scarcity …  相似文献   

11.
1 Introduction 1 It has been reported that the morbidity caused by indoor air pollution accounts for 4% of all diseases in the world, which is about the same portion of diseases caused by alcohol and cigarette. Indoor air pollution is the fourth one of the dangerous elements for the inhabitants and even more dangerous than outdoor air pollution. The bulletin of World Health Organization (WHO) [1] points out that the indoor air pollution is an important issue to environment and public health.…  相似文献   

12.
In this paper, a novel system using direct contact heat transfer between air and water solution was proposed to generate ice slurry. The heat transfer process and the system performance were studied; energy efficiency coefficients of 0.038, 0.053, and 0.064 were obtained using different solutions. An empirical relationship between the volumetric heat transfer coefficient Uv and the main parameters was obtained by fitting the experimental data. The Uv calculated from the empirical formula agreed with the experimental Uv quite well with a relative error of less than 15%. Based on the empirical formula, a laboratory-scale direct contact ice slurry generator was then constructed, with practical application in mind. If the air flow rate is fixed at 200 m3/h, the ice production rate will be 0.091 kg/min. The experimental results also showed that the cold energy consumption of the air compressor accounted for more than half of the total amount. To improve the system energy efficiency coefficient, it is necessary to increase the air pipes insulation and the solution's thermal capacity, and also it is appropriate to utilize the free cold energy of liquefied natural gas (LNG).  相似文献   

13.
A one-dimensional column is set up to study the mass transfer during air sparging process for methyl tertiary butyl ether(MTBE) removal in saturated soil and groundwater, with the condition of different airflow and soil penetrability. It is shown that the removal rate of MTBE can reach 80%, 90% and 95% when airflow is 0.05 m3/h, 0.085 m3/h and 0.10 m3/h, respectively. Increasing airflow will help to increase the removal rate of dissolved MTBE, but eventually a threshold removal rate is reached, above which further increasing air injection rates does not increase the removal rate. Fine sand allows the injected air to travel in bubble form, while coarse sand and medium sand allow the injected air to travel in the form of discrete channels; the greater the soil grain size is, the more extensive the channel net work forms, which in turn leads to higher removal rate. A tailing effect of lingering residual contaminant concentrations occur within the fine sand. About 20% of MTBE cannot be removed.  相似文献   

14.
Saving the Earth     
As time goes by,humans are making the earth sick.People cut down too much trees ① and leave more and more rubbish here and there.Factories let out their waste without doing anything to it.All this has caused many serious problems.More and more good farmland has turned into desert,the rivers and lakes have polluted② and the water in them is dirty and poisonous.The air is less clean,even the temperature of the earth is higher than before.The earth is sick now.What should we do to save her?  相似文献   

15.
The water mitigation effect on the propagation of shock wave was investigated numerically. The traditional smoothed particle hydrodynamics (SPH) method was modified based on Riemann solution. The comparison of numerical results with the analytical solution indicated that the modified SPH method has more advantages than the traditional SPH method. Using the modified SPH algorithm, a series of one-dimensional planar wave propagation problems were investigated, focusing on the influence of the air-gap between the high-pressure air and water and the thickness of water. The numerical results showed that water mitigation effect is significant. Up to 60% shock wave pressure reduction could be achieved with the existence of water, and the shape of shock wave was also changed greatly. It is seemly that the small air-gap between the high-pressure air and water has more influence on water mitigation effect.  相似文献   

16.
We proposed a novel impact pneumatic cylinder with a reservoir connected to the inlet chamber so that the pneumatic cylinder can achieve a high speed. A reservoir with high-pressure air enabled the cylirider to achieve considerable'acceleration when it began to Work. We established a mathematical model to simulate the behaviors of an impact pneumatic cylinder, focusing on the relationships of the maximum piston speed with the air supply pressure and the reservoir volume. The results show that the reservoir .can help significantly enhance the pneumatic system velocity. When the reservoir volume is less than double the cylinder volume, an increase in the reservoir volume is more effective in increasing the maximum piston velocity.  相似文献   

17.
风之影     
The air is a sea of gases, And the wind is restless waves;When it wants it can sustain life,And take it when it craves. A flame can live with ardor,Its posture straight and strong,When the wind is quiet and gentle,For it becomes a loving mate. And, then, when fancy strikes.It can blow a strong willed gust.That will extinguish a struggling flame,And turn to less than dust. The wind is air at peace,In love, it is a breeze;Disturbed and angry it becomes a storm,That tears down mighty trees.  相似文献   

18.
Indoor air quality and thermal comfort are important features of indoor environment, In this paper, a numerical simulation based on the k-ε model of CFD is used to analyze factors such as loading, exterior-protected construction, blowing-in rate that play an important role in the temperature field and airflow field of the displacement ventilation system. Exterior-protected construction has little influence on indoor temperature distribution of displacement ventilation systems and the influence is limited only in a small area near the external wall when the indoor heat source is the main cooling load. The height of a room has little influence on indoor temperature field, and the temperature gradient of active region is basically unchanged. In the system combined with a displacement ventilation system and a cooling system, the height also has little influence. When the cooling load is high,the indoor heat source creates a strong convective plume, which will make the average indoor air age lower, the ventilation efficiency higher and the elimination of pollutant easier. Air supply rate plays an important role in displacement ventilation systems. The increase of air supply rate that can be realized by increasing the air supply velocity and enlarging the area of air inlet will increase the mass capability of the system and diminish the vertical temperature gradient. From the comparison between simulations and experiments, it is concluded that this simulation are creditable.  相似文献   

19.
With the fast development of Chinese economy and society,the communication between China and foreign countries has been more and more frequent.And China is a country where English is taught as a foreign language.Therefore cultural differences have become more and more significant in English teaching.Both language teachers and students should be aware of the differences between eastern and western culture in their teaching and study.  相似文献   

20.
Two Gaussian air quality dispersion models, the industrial source complex short-term model (ISCST3) with and without modification have been used to simulate the pollutant concentration distribution in urban areas based on the meteorological data and the emissions distribution of sulfur dioxide. The verified data show that the modified model is more accurate in the urban area of Shijiazhuang. Using the modified model predictions, the control strategies of sulfur dioxide in the urban area have been studied, and the result show that the second long-term (to 2010) strategy can mitigate air pollution significantly and maintain pollution levels within permissible limits.  相似文献   

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