9,057 research outputs found
A Survey on the Cultivation of College Students’ Audience Awareness in English Writing
The strength of audience awareness has a great influence on the content selection, expression and writing techniques of the article. Therefore, the cultivation of the students’ audience awareness in writing becomes one of the key factors that determine the qualities of the students’ compositions. This thesis conducts a questionnaire and interviews on college students from the four grades of Nanchang Normal University in order to reveal the college students’ cognitive status and attitude of audience awareness. Based on the status quo, this thesis analyzes the possible causes of this situation from two aspects: the teachers’ carelessness on audience awareness and overly concern with writing skills, and the students’ shortage of language ability and logical thinking ability and their excessive attention to writing skills. For these reasons, this thesis proposes corresponding countermeasures: in the English writing class, the reader's awareness should be emphasized; the theme of the article needs to be much closer to life; students are supposed to create imaginary readers in writing; the method of readers' feedback should be fully utilized. The use of these strategies will effectively help college students cultivate audience awareness in English writing
Characteristics of the Bohai Sea oil spill and its impacton the Bohai Sea ecosystem
In this paper, ENVISAT ASAR data and the Estuary, Coastal and Ocean Model was used to analyze and compare characteristics of the Bohai Sea oil spill. The oil slicks have spread from the point of the oil spill to the east and north-western Bohai Sea. We make a comparison between the changes caused by the oil spill on the chlorophyll concentration and the sea surface temperature using MODIS data, which can be used to analyze the effect of the oil spill on the Bohai Sea ecosystem. We found that the Bohai Sea oil spill caused abnormal chlorophyll concentration distributions and red tide nearby area of oil spill.</span
Semi-Numerical Simulation of Reionization with Semi-Analytical Modeling of Galaxy Formation
In a semi-numerical model of reionization, the evolution of ionization
fraction is simulated approximately by the ionizing photon to baryon ratio
criterion. In this paper we incorporate a semi-analytical model of galaxy
formation based on the Millennium II N-body simulation into the semi-numerical
modeling of reionization. The semi-analytical model is used to predict the
production of ionizing photons, then we use the semi-numerical method to model
the reionization process. Such an approach allows more detailed modeling of the
reionization, and also connects observations of galaxies at low and high
redshifts to the reionization history. The galaxy formation model we use was
designed to match the low- observations, and it also fits the high redshift
luminosity function reasonably well, but its prediction on the star formation
falls below the observed value, and we find that it also underpredicts the
stellar ionizing photon production rate, hence the reionization can not be
completed at without taking into account some other potential
sources of ionization photons. We also considered simple modifications of the
model with more top heavy initial mass functions (IMF), with which the
reionization can occur at earlier epochs. The incorporation of the
semi-analytical model may also affect the topology of the HI regions during the
EoR, and the neutral regions produced by our simulations with the
semi-analytical model appeared less poriferous than the simple halo-based
models.Comment: 13 pages, 8 figures, RAA accepte
Laplacian eigenvalue distribution, diameter and domination number of trees
For a graph with domination number , Hedetniemi, Jacobs and
Trevisan [European Journal of Combinatorics 53 (2016) 66-71] proved that
, where means the number of Laplacian
eigenvalues of in the interval . Let be a tree with diameter
. In this paper, we show that . However, such a
lower bound is false for general graphs. All trees achieving the lower bound
are completely characterized. Moreover, for a tree , we establish a relation
between the Laplacian eigenvalues, the diameter and the domination number by
showing that the domination number of is equal to if and only if
it has exactly Laplacian eigenvalues less than one. As an
application, it also provides a new type of trees, which show the sharpness of
an inequality due to Hedetniemi, Jacobs and Trevisan
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