Learning Mathematics： Themes,Concepts, and Relationships

This study investigated the intellectual structure of research into the instruction of mathematics by identifying the most influential scholars and the most important publications using bibliometric analysis and tag cloud analysis. We analyzed 33,021 citations in 1,016 articles published in Science Citation Index （SCI） and Social Sciences Citation Index （SSCI）journals in the field of mathematics instruction between 2002 and 2011 in order to create a knowledge map. The results of this mapping were used to identify the direction of research into the instruction of mathematics, providing a valuable tool for researchers seeking to access the literature in this area.     

It works in practice

More tested lessons, suggestions, tips and techniques which have all worked for ETρreaders. Try them out for yourself - and then send us your own contribution.All the contributors to It Works in Practice in this issue of ETρwill receive a free copy of The Language Teacher's Voice by Alan Maley, published by Macmillan. Macmillan have kindly agreed to be sponsors of It Works in Practice for the coming year and contributors will be given copies of books in their Teacher Development Series.     

Vacuum interrupter, high reliability component of distribution switches, circuit breakers and contactors

The use of vacuum interrupters(VIs)as the current interruption component for switches,circuit breakers,reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950’s.This electrical product has developed a dominating position for switching and protecting distribution circuits.VIs are even being introduced into switching products operating at transmission voltages.Among the reasons for the VI’s popularity are its compactness,its range of application,its low cost,its superb electrical and mechanical life and its ease of application.Its major advantage is its well-established reliability.In this paper we show how this reliability has been achieved by design,by mechanical life testing and by electrical performance testing.We introduce the“sealed for life”concept for the VI’s integrity.We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years.We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity.Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments.     

谢谢您,迪薇莜夫人

We were sitting in her classroom, giggling,jabbing each other and talking about the latestinformation of the day, like the peculiar purple-colored mascara Cindy was wearing. Mrs. VirginiaDeView cleared her throat and asked us to hush."Now," she said smiling, "we are going todiscover our professions." The class seemed to gasp in unison. Ourprofessions? We stared at each other. We were only13 and 14 years old. This teacher was nuts.That was pretty much how the kids looked atVirginia De…     

Transient Heat Transfer Study of Direct Contact Condensation of Steam in Spray Cooling Water

We conducted a transient experimental investigation of steam–water direct contact condensation in the absence of noncondensible gas in a laboratory-scale column with the inner diameter of 325 mm and the height of 1045 mm. We applied a new analysis method for the steam state equation to analyze the molar quantity change in steam over the course of the experiment and determined the transient steam variation. We also investigated the influence of flow rates and temperatures ofcooling water on the efficiency ofsteam condensation. Our experimental results show that appropriate increasing of the cooling water flow rate can significantly accelerate the steam condensation. We achieved a rapid increase in the total volumetric heat transfer coefficient by increasing the flow rate of cooling water, which indicated a higher thermal convection between the steam and the cooling water with higher flow rates. We found that the temperature ofcooling water did not play an important role on steam condensation. This method was confirmed to be effective for rapid recovering ofsteam.     

People,Why do you Do That?

I am a fish. When I was born, I was very small, and my father andmother both loved me very much. My home was in a river, and I had alot of friends.They were all beautiful and healthy fish. We often playedgames together happily. We found that our home——the river was very cleanand beautiful.We all loved her.     

Review of Metaphors We Live By

"Metaphors We Live By"was written by George Lakoff and Mark Johnson in Chicago in 1980 published by University of Chicago Press. Lakoff and Johnson’s"Metaphors We Live By"(1980) is an important contribution to the study of metaphor.     

孟买的圣诞节

We arrived in Bombay early in December, all agog to see the wonders of one of India principal cities and looking ahead to visiting Delhi, Agra and the Taj Mahal, even the Khyber Pass, Afghanistan and Karachi. We accomplished only the first of these. After one night in Bombay we awoke to the news that India and Pakistan were at war.     

Science Letters： Brain natriuretic peptide： A potential indicator of cardiomyogenesis after autologous mesenchymal stem cell transplantation？

We observed in a pilot study that there was a transient elevation of brain natriuretic peptide （BNP） level shortly after the transplantation in the patient with ischemic heart failure, which is unexplainable by the simultaneous increase of the cardiac output and six-minute walk distance. Similar findings were observed in the phase I trial. We postulated on the basis of the finding of Fukuda in vitro that this transient elevation of BNP level against the improvement of cardiac function and exercise capacity might indicate cardiomyogenesis in patients after mesenchymal stem cell transplantation. Further study is warranted to verify the hypothesis.     

牛津（7上）由误及正步步高

1．我们坐在教室的后面。 【误】We sat on the back of the classroom. 【正】We sat in the back of the classroom.     

幸福,是个抉择

If it'S possible to see red(火冒三丈)about not seeing red,that is what Iwas doing.We had misjudged(错误判断,错误估计)the timing of our autumntrip to see the changing leaves in the Great Lakes states,and I was reallyupset.No matter how I strained my eyes,I couldn't spot red anywhere.NOteven a hint of golden yellow broke through the monotonous greenery. I recalled an earlier leaf-viewing trip to Vermont in October,and the     

Mercury pollution in the Chongqing part of the Three Gorges Reservoir area and its remediation and prevention

Mercury pollution in the Three Gorges Reservoir area of P. R. China merits special attention. We investigated into the current situation in the Chongqing part of the Reservoir area, identified the pollution sources and proposed some suggestions for the remediation and prevention of mercury pollution in this area. Atmospheric mercury in Chongqing was mainly from coal burning and releases of mercury-containing products such as various types of lights and fever thermometers. Urban drainage in Chongqing and Changshou, and runoffs from the high mercury background area in the lower reaches of the Wujiang River contributed most of the mercury in the water of the Yangtze River. A majority of the blame should be laid on mercury and gold mining in the Wujiang valley. We suggested foresting sloping lands to relieve soil erosion and prevent mercury-bearing soil from running into rivers, educational activities to discourage use of mercury-containing products and improved infrastructure to collect mercury-containing wastes for reducing mercury releases, more facilities for treating wastewater and solid waste to accommodate increased requirements of discharge, and growing selected perennial plants in mercury-contaminated land to absorb the mercury in soil. We also suggested concerted operation of a dedicated water-quality monitoring system, reinforced legislation and an effective administrative mechanism to ensure lasting efforts are invested in curbing mercury releases and restoring mercury contaminated land and water in the Reservoir area.     

How We Teach English at Zhaotong Teacher's College

We arrived at Zhaotong Teacher's College in September 1996. We were teaching oral English and listening comprehension, as well as British and American culture. The students were afraid of us, they did not dare to speak to us in or out of the classroom, and although they had many questions about our homeland, lifestyle and culture, they never asked them. Now, 8 months later, everything is different. We have tried to create an English environment in the English department by giving all     

Geochemical characteristics of the fluid inclusions in the Gangxi Fault Belt, Huanghua Depression, Bohai Bay Basin, China

We studied the geochemical characteristics of the fluid inclusions in the Ordovician carbonates and the Oligocene Shahejie Formation sandstones from 15 wells in the Gangxi Fault Belt, Huanghua Depression. The fluid inclusions are all sec- ondary with gas/liquid ratio of 5%~10%. Base on Raman they are mainly composed of H2O, CO2 and CH4. The homogenization temperatures, combined with burial and geothermal history of the host rock, indicate that the fluid flows in the Shahejie Formation and the Ordovician carbonates were trapped in Neocene. Using a VG5400 mass spectrometer, the helium isotopic compositions were analyzed. Interpretation of results suggested a significant amount of mantle-derived helium mainly accumulating in the intersections of the NWW trending Xuzhuangzi and NE trending Gangxi faults. The maturity of hydrocarbon decreases from the intersection to the outside pointing out that the fluid related to the NWW trending Xuzhuangzi and NE trending Gangxi faults. These factors implied the fluid inclusions have a close relationship to the local tectonic setting. Gangxi Fault Belt experienced intensive Neo-tectonic activities in Cenozoic. Widespread faulted-depressions and strong volcanic eruptions manifested its tec- tonic status of extensional stress field. Mantle uplift caused the movement of magma that carried mantle-derived gases and deep heat flows, the deep-rooted tension faults provided the passages for the gases and heat flows to shallow crust levels.     

Corrosion of carbon steel, zinc and copper by air pollution in Chongqing

This paper presents the research on the atmospheric corrosion rates of carbon steel, zinc and copper in Chongqing, which was a corrosion subprogram of an international project, Regional Air Pollution in Developing Countries. We performed field exposure tests of carbon steel, zinc and copper at an urban site Guanyinqiao and a rural site Tieshanping inChongqing, then used grey relational analysis, based on the database of the whole corrosion project, to determine the order of the effect of environmental factors on corrosion rates of tested metals, and established dose-response functions for these three metals. The results showed that the two crucial agents of acidic environment, SO2 and H , were common factors that contributed most to the corrosion of the tested metals. The established dose-response functions for outdoor carbon steel and zinc are proved applicable to use in Chongqing, but the function for copper needs further modifying. We employed these dose- response functions and general environmental data to elaborate the maps of corrosion rate respectively of carbon steel and zinc by geological information system (GIS) technique which help to identify areas of high corrosion damage risk. An acceptable annual average SO2 level of 21 μg/m3 for carbon steel and that of 61 μg/m3 for zinc are also put forward to control the air pollution impact on atmospheric corrosion in Chongqing urban areas.     

教你正确用(十七)

Last month,I spent a few days in Beijing—quite aplace now.English has definitely become animportant part of the life of this cosmopolitancity.Most signs in restaurants,department stores,andon highways are not only in Chinese but also inEnglish.Today,let’s have a little chat on the“signlanguage”—not the sign language with hand gesturesfor people who are not able to hear or speak,butEnglish that appears in some of the signs in Beijing.We lc o me—We lc o me Aga in欢迎光临与欢迎下次光临T…     

Fuzzy comprehensive evaluation of bridge quality based on analytical hierarchy process

Bridge quality assessment is an important part in the final acceptance of new bridge construction,and it is also the main basis for the reinforcement or removal of old bridges.We evaluated the weight of each affecting factor to the upper events using progressive analytical hierarchy process(AHP)with the adoption of 3 scaling,reduced the calculation in analytical process,and precluded the nonuniformity of the scaling system.We obtained a comprehensive evaluation system of bridge quality, and verified its pra...     

The Life in the Camp

We once had a whole week of life in the army camp. It was a life full of happinessand interest. That was in the first year of my primary school. All of us were excitedwhen teacher announced2 that we were about to pass a week in the camp. Can you imagine t…     

Entanglement of two-level atoms''''quantum states in a strong thermal radiation field

The two-level atom is described by Pauli sign and environment is described by infinite harmonic particle thermal reservoir.We have studied the entanglement of two-level atoms which are put in the strongly thermal radiation field.The two-level atoms' reducible density rectangular array is obtained.We discuss the properties of entanglement by virtue of concurrence.It is shown that the two two-level atoms initially situated in different coherent superposition states,entanglement of atoms have obvious dissimilarity.