Molecular dynamics simulation of liquid-vapor surface tension

A molecular dynamics simulation model is established based on the well-known Lennard-Jones 12-6 potential function to determine the surface tension of a Lennard-Jones liquid-vapor interface.The simulation is carried out with argon as the working fluid of a given molecular number at different temperature and different truncated radius.It is found that the surface tension of a Lennard-Jones fluid is likely to be bigger for a bigger truncated radius,and tends to be constant after the truncated radius increased to a certain value.It is also found that the surface tension becomes smaller as the temperature increases.     

Measurement of incompatible probability in information retrieval: A case study with user clicks

The incompatible probability represents an important non-classical phenomenon, and it describes conflicting observed marginal probabilities, which cannot be satisfied with a joint probability. First, the incompatibility of random variables was defined and discussed via the non-positive semi-definiteness of their covariance matrixes. Then, a method was proposed to verify the existence of incompatible probability for variables. A hypothesis testing was also applied to reexamine the likelihood of the observed marginal probabilities being integrated into a joint probability space, thus showing the statistical significance of incompatible probability cases. A case study with user click-through data provided the initial evidence of the incompatible probability in information retrieval (IR), particularly in user interaction. The experiments indicate that both incompatible and compatible cases can be found in IR data, and informational queries are more likely to be compatible than navigational queries. The results inspire new theoretical perspectives of modeling the complex interactions and phenomena in IR.     

英国儿童做家务以赚钱(英文)

Children in Britain earn much pocket money by doing housework. 在英国.儿童做家务得到可观的零用钱。In Britain, a study of children's pocket money was done last year. The study covered 702 households. It showed that pocket money has become big business for children. About 20% of children earn ?200 (about 15,000 RMB) a year for doing basic housework.·Children are more unwilling to do housework than before. 儿童比以往较不愿意做家务。The study found that children are more unwilling to do housework than before. They do much less around the house.     

The Effect on Enhancing Students＇ Inquiry Abilities via Step-by-Step Open-ended Inquiry Teaching Design

The purpose of this study is to promote more open-ended inquiry activities in junior high school science lessons in the current educational system with fixed textbooks. Researchers adapted existing curriculum-based experimental activities for more open-ended inquiry ones. In addition, the whole class was provided with more opportunities to explore complete activities in limited teaching time. This study used Hazel＇s proposals of levels of inquiry. The method was to carry out the current 8th grade experiments through the step-by-step teaching material modification （from levels of inquiry 0 to 2b） and to combine the experimental teaching method with the 5E （engage, explore, explain, elaborate, and evaluate） learning cycle. After a quasi-experimental study, we compared the traditional teaching method with the step-by-step open-ended inquiry teaching one on 8th graders＇ basic and integrated science process skills and academic achievements. The study result showed that the academic achievement in the experimental group, based on the same instructional time, was not worse than that in the control group. No significant difference was found on the total scores of the basic science process skills between the two groups, but a significant difference was found on the ＂predicting＂ dimension. There was a significant difference on the total scores of the integrated science process skills between the two groups. Significant differences were found on ＂interpreting data＂ as well as ＂experiment designing＂ dimensions. Hence, the study indicated that it could enhance students＇ inquiry ability through step-by-step openly inquiry levels to change the existing curricula, which served as a reference of educational reform.     

气泡内也有原子反应?

Agroup of scientists claims to have found evidence of nuclear fusion in a vase-size flask of liquid. The researchers say they created tiny bubbles that seemed to have collapsed with enough violence to force atomic nuclei to fuse. Skepticism about the results outweighs confidence in them. National Laboratory and his colleagues are confirmed, scientists will have a new way to study fusion reactions. A far more speculative and exciting possibility is that the tabletop experiments might lead to the long-sought goal of harnessing fusion for gener-     

季节如何影响你的睡眠？

<正>After a long winter, the arrival of spring can be a welcome relief. The days grow longer, the temperatures increase, and the natural world around us comes to life again. But when the seasons change, our sleep patterns change with them.New research suggests that humans may need more sleep in the winter than they do in the summer. A German study found that participants slept an hour longer in December than in June, regardless of their exposure to light. “Our study shows that even while li...     

Practice on assessing grammar and vocabulary： The case of the TOEFL

The Test of English as a Foreign Language （TOEFL） brings tremendous influence to EFL （English as a Foreign Language） learners worldwide. TOEFL 2000 project claims that TOEFL, as a more reflective of communicative model, could provide more information about international students＇ language ability that it is supposed to measure. However, after detailed analyzing an authentic paper-based test paper in May, 2001 in China as a sample from four aspects--test reliability, construct validity, authenticity and interactiveness respectively, it is found that the test puts too much emphasis on vocabulary and grammar knowledge within almost every session of the test paper, in which ＂structure and written expression＂ could be the most disputed part. The content could not fully demonstrate its validity and communicative purposes so that it is suspected that test takers could meet the later demands in academic study abroad. Nevertheless, this is a powerful explanation about the current revolutionized change in the framework and content of TOEFL to meet the principles of designing a test, which could provide more information and guidance for later test designs.     

What 37,000 citations can tell

A longitudinal study at the TUT （Tshwane University of Technology） used citation analysis to analyze the reference lists of 480 Master＇s and Doctoral （M and D） theses and dissertations submitted at TUT between 2004 and 2007. The purpose was to determine what types of information sources M and D students at TUT use most, how the patterns of use differ across the 7 faculties of the university, and to what extent the LIS （Library and Information Services） keeps or provides access to the journals that are mostly used by M and D students. More than 37,000 citations were analyzed over the 4-year period. The study found several similarities but also some distinct differences in the use of information sources across the 7 faculties of TUT. It also identified more than 60 different information sources used by M and D students. With regard to journal use, the study found that out of 3,641 different journals cited, most journals were only cited once over a period of 4 years. However, a small percentage of journals were highly and/or frequently cited.     

Pilgrim's Progress, Progress of Salvation

Through a comparative analysis of The Pilgrim’s Progress and The Journey to the West, the paper aims to reveal what common ground is shared by the two novels and what light is thrown on the theme of spiritual salvation. The fruit of the study leads to a conclusion that both novels have employed religious doctrines and social criticisms to make the theme of spiritual salvation more palatable for their readers.     

一句话新闻 始回顾

性格决定外表If you exhibit positive traits such as honesty and helpfulness,the chances are that you will be perceived as a good looking person,for a new study has found that the perception of physical attractiveness is influenced by a person's personality.The study found that people who exhibit negative traits,such as unfairness and rudeness,appear to be less physically attractive to observers.