Solvent and electric field dependence of the photocurrent generation in donor：acceptor blend system

This paper reports that the blend films of poly （2-methoxy-5-（2＇-ethyl-hexyloxy）-p-phenylene vinylene） （MEH-PPV） and N,N＇-bis（1-ethylpropyl）-3,4： 9,10-perylene bis （tetracarboxyl diimide） （EP-PDI） with the weight ratio of 1：2.5 have been prepared by spin-coating from chloroform （CF） and chlorobenzene （CB） solutions respectively. The absorption spectra and the morphology of the blend films show that large crystal-like EP-PDI aggregates are formed in film prepared from CB solution, which corresponds to a new absorption shoulder near 590 nm, while there is no shoulder around 590 nm in the UV-Vis absorption spectra of the blend film from CF solution. The electric-field dependence spectra of the photocurrent generation quantum yield of the film from CB solution shows that at weak electric field the EP-PDI aggregates act as more efficient sensitizers, but at strong electric field the quantum yields become almost invariable over the entire spectral range no matter what the state of EP-PDI, monomer or aggregate. At strong electric field, the photocurrent generation yields of both films from CF and CB solution saturate and their yield spectra become spectrally similar, mentioning that at strong electric field the photoexcitons dissociate efficiently and the free charges are collected by the electrodes almost completely.

Field dependence of magnetoresistance in epitaxial single-crystal La_(2/3)Ca_(1/3)MnO_(3-δ) thin film

Epitaxial La2/3Ca1/3 MnO3 thin films were prepared on NdGaO3(110) substrates by d. c. magnetron sputtering method. The measurements of magnetoresistance ρ(H) upon magnetic field at different temperatures were carried out in the field range of 0 - 8 T. It is found that p(H) obeys the following relations: when the temperature(T) is higher than the Curie temperature Tc, ρ ( H ) =1/α(T)+β(T)H2; below Tc, ρ ( H ) = ρ0 ( T ) 1/A(T)+B(T)exp(H/C(Y)),and ρ(H) =1/κa(T)+γ(T)H when T is far below TC. It is Suggested that the negative magnetoresistive effect is mainly due to enhancement of the magnetoconductance.

Rapid transition of the hole Rashba effect from strong field dependence to saturation in semiconductor nanowires

With the support by the National Natural Science Foundation of China,a study by the research group led by Prof.Luo Junwei(骆军委)from the Institute of Semiconductors,Chinese Academy of Sciences discovered a rapid transition of the hole Rashba effect from strong field dependence to saturation

Learners＇ Cognitive Styles and Foreign Language Teaching

Individual learners possess distinctive cognitive styles which have a great effect on foreign language learning. The present paper intends to study the relationship between foreign language learning proficiency and cognitive styles from the perspectives of psychology, psycholinguistics, and second language acquisition. Through the analysis, the author has arrived at a conclusion that learners with different cognitive styles adopt quite different strategies in learning a foreign language. The best-matched methods fitting for different cognitive styles may help learners improve their learning proficiency. Therefore, in order to improve teaching proficiency, foreign language teachers should keep a match between learners＇ cognitive styles and teaching methodologies.

Coinoculation of bioinoculants improve Acacia auriculiformis seedling growth and quality in a tropical Alfisol soil

We conducted a study to find out if arbuscular mycorrhizal(AM) fungi(Acaulospora scrobiculata,Scutellospora calospora) and phosphate solubilizing bacteria(PSB, Paenibacillus polymyxa) inoculation either individually or in combinations can improve Acacia auriculiformis seedling growth, uptake of nutrients and quality in a phosphorus deficient tropical Alfisol. The seedlings were assessed for various growth and nutrient uptake parameters after 60 days of treatment. Inoculation with P.polymyxa stimulated mycorrhizal formation. Seedling height, stem girth, taproot length, number of leaves and leaf area, plant dry matter production, nodulation, and nodular dry weight were significantly higher for seedlings that were either dual inoculated or triple inoculated compared to individual inoculation of AM fungi or PSB, and uninoculated seedlings. Dual and triple application of AM fungi and PSB also significantly improved the nutrient contents of shoots and roots and nutrient uptake efficiencies. The calculated seedling quality indexes of the AM fungi and PSB inoculated seedling were 25–208% higher than uninoculated seedlings. These findings show that A.auriculiformis seedlings when dual inoculated or triple inoculated performed better than seedlings inoculated with the microbes individually and compared with uninoculated control seedlings. We conclude that bioinoculation is important for the production of high-quality A.auriculiformis seedlings in tree nurseries for planting in nutrient deficient soils.

THE INFLUENCE OF COGNITIVE STYLE AND READING STRATEGIES ON ENGLISH READING: AN EMPIRICAL STUDY

This paper presents the results of a research study carried out with students of China University of Geosciences to analyze the influence of readers' cognitive styles (field dependent/field neutral/field independent) and reading strategies on their reading performance, including the total reading score, global inference questions, factual and detail questions, main idea questions, lexical inference questions. Results show the correlations between cognitive style and most of the reading questions are not statistically significant, except for the total reading scores and performance of global inference question. One-way ANOVA shows that there is significant difference between the FN and FD group in total reading score and global inference question. However, when the reading strategies have been partialled out of the correlations between cognitive style and reading scores, the remaining correlation with the total reading score and global inference and lexical inference reaches significance. This indicates the different information processing of FD/FI learners and the important role of direct reading strategies for all learners. Teachers can help their students become more effective readers by encouraging them to apply direct reading strategies, and apply different indirect reading strategies based on their different cognitive styles.

THE THEORY OF FDI AND ITS IMPLICATIONS IN ENGLISH LANGUAGE TEACHING AND LEARNING

As an important dimension of cognitive style, field dependent (FD) and field independent (FI) have been extensively investigated in various aspects of language teaching and learning. It is widely believed that the FDI characteristics can provide important information in contributing to students' success and individualizing educational programs. Based on the previous studies, the present paper aims to make a detailed theoretical survey of FDI and to discuss its implications in English language teaching and learning. It is hoped that the research offers some insight into the theory of FDI and the employment of the theory in the classroom. Some problems and suggestions are also put forward for further consideration.