Fe-MCM-22 zeolites: synthesis and study about the states of iron

The Fe-MCM-22 zeolite was successfully synthesized with hexametylenimine template. Several physicochemical techniques (XRD, SEM, BET, AAS, IR and ESR) have been used to characterize this zeolite. Iron exists under three states: isolated ions in tetrahedral lattice positions, in octahedral coordination as isolated ions at cationic positions and as aggregated oxide species or hydroxide phases.Keywords: Fe-MCM-22 zeolite, synthesis, characterization, framework iron

Seasonal variation of phytoplankton in Tuyen Lam reservoir in Da Lat, Vietnam

Seasonal variation and phytoplankton dynamics in Tuyen Lam reservoir in Da Lat city, Viet Nam were studied in the rainy and dry seasons (during January through December, 2014). Samples were taken monthly from 3 stations of Tuyen Lam reservoir. The aim of this study was to analyze the structure of the phytoplankton community on seasonal scales and to identify the environmental factors, such as temperature, conductivity, pH, dissolved oxygen, light intensity, transparency, ammonium, nitrate and phosphate controlling the phytoplankton density and composition of phytoplankton communities. The results showed that phytoplankton comprised 43 taxa, mainly Chlorophyta (58%), Bacillariophyta (14%), Cyanobacteria (14%), Dinophyta (7%), Chrysophyta (5%) and Euglenophyta (2%). There was significant difference in phytoplankton abundance but not species richness between two seasons. Multiple regression analysis between chlorophyll a contents, phytoplankton density with environmental independent variables indicated that ammonium, nitrate concentrations and water temperature were significantly impact to the abundance of phytoplankton, while almost no independent variables were found to correlate to chlorophyll a. CCA analysis phytoplankton and abiotic parameters revealed several species groups with their favorable environmental conditions

Photon - Axion Conversion Cross-Sections in a Resonant Cavity with general mode

Photon-axion conversions in the resonant cavity with the general mode (TM$_{mn0}$) are considered in detail by the Feynman diagram method. The differential cross-sections are presented and numerical evaluations are given. It is shown that there is a resonant conversion for the considered process, in which the conversion cross-sections are much larger than those of the wave guide in the same conditions. Some estimates for experimental conditions are give from our results

Hematological parameters of red tilapia (Oreochromis sp.) fed lemongrass essential oil (Cymbopogon citratus) after challenge with Streptococcus agalactiae

The study involved feeding lemongrass essential oil (LEO) supplements to red tilapia (Oreochromis sp.) at concentrations including Control - 0 mg, T1 – 200 mg, T2 – 300 mg, and T3 – 400 mg per kg of feed. The research investigated changes in hematological (HCT, Hb, RBC, WBC & thrombocytes) and erythrocyte’s morphological (major/minor axis; perimeter, and area of erythrocyte) parameters before infection, 5- and 10-days post-infection (DPI). According to analytical findings, a diet containing LEO enhanced the synthesis of both erythrocytes and leukocytes in the peripheral blood of red tilapia after 20 days of being used. Therefore, the indicators of this group of fish showed better performance than those that did not use LEO supplement five days after bacterial infection. Fish fed 200 mg/kg of LEO after being challenged with S. agalactiae for ten days showed an improved effect on red blood cell production. White blood cells decreased at all concentrations because of citral’s immunomodulatory properties

COPPER-MODIFIED MCM-22 AS CATALYSTS FOR HYDROCARBON SELECTIVE CATALYTIC REDUCTION OF NOX

Joint Research on Environmental Science and Technology for the Eart

A STUDY ON PROBLEMS IN SPEAKING OF ENGLISH-MAJORED FRESHMEN AT TAY DO UNIVERSITY AND SOME SUGGESTED SOLUTIONS

In this globalization era, there have been drastic changes taking place all over the world. People’s desires are fulfilled when they clearly express their ideas and opinions to others. Thus, they need to learn speaking skills in order to fulfill their ambitions, desires, and goals. However, it is so difficult for students to master this skill because they encounter some common problems when speaking. Therefore, the research entitled "A study on problems in speaking of English-majored freshmen at Tay Do University and some suggested solutions" was carried out in order to identify common problems in English speaking of English majored freshmen at Tay Do University and provide some suggested solutions. In this study, questionnaires and interview papers were used as the main instruments to collect the data. The participants were 80 English-majored freshmen in the two classes of English course 16 including 16A and 16B at Tay Do University. The study's findings revealed that freshmen majoring in English had several common problems with vocabulary, pronunciation, grammar, the influence of mother tongue, and psychology in speaking. It is expected that this study will assist English-majored freshmen at Tay Do University in recognizing and overcoming obstacles in the process of speaking.  Article visualizations

ENGLISH-MAJORED STUDENTS’ LISTENING DIFFICULTIES AND USE OF STRATEGIES AT MIEN DONG UNIVERSITY OF TECHNOLOGY, VIETNAM

Through the years, difficulties in English listening and listening strategies have been conducted by many researchers. Most of studies have pointed out the common difficulties and strategies which students often have. Focusing on the same subject with a new perspective, this research aimed at understanding English majors’ difficulties in listening and use of listening strategies. A total of ninety eight freshmen English-majored students at Mien Dong University took part in answering the questionnaire and five students answered the semi-structure interview questions. The data gained from the questionnaire were analyzed by SPSS version 20.0 in terms of descriptive statistic. The findings revealed that English-majored students had many difficulties in listening such as the difficulties related to the listener, the content of the dialogue, the speaker, the physical setting and the linguistic factors. In terms of listening strategies, the finding showed that the cognitive listening strategies were used more frequently than metacognitive and socio-affective strategies. Based on the findings, some implications were made to contribute to the administrations, teachers and students at Mien Dong University of Technology.  Article visualizations

AN INVESTIGATION INTO THE USE OF COLLOCATIONS IN ACADEMIC ESSAYS OF ENGLISH-MAJORED STUDENTS OF THE HIGH-QUALITY PROGRAM AT CAN THO UNIVERSITY, VIETNAM

One of the main goals of language learners is to master all four skills of listening, speaking, reading and writing when it comes to their acquisition of the target language. However, during the process of learning English, learners inevitably face a variety of challenges related to their writing including grammatical errors, word choice, organization, idea development, and most importantly their difficulties in using collocations (Duong & Nguyen, 2021). Therefore, this study has been conducted to investigate the students’ use of English collocations in their academic essays associated with their difficulties so that appropriate pedagogical approaches and practices would be taken into consideration in order to help students improve their English collocational competences in academic writing. This descriptive study was carried out with 103 English-majored students of the High-quality program of the School of Foreign Languages at Can Tho University, Vietnam. A 5-point Likert scale survey with 18 questionnaire items was employed to examine the frequency of students' exposure to as well as their usage of English collocations, and their difficulties in using English collocations. The results of this study have shown that the most commonly used collocations in the students’ academic essays were ‘verb + noun’, and ‘adjective + noun’ lexical collocations. Additionally, the research outcomes have revealed that the types of English collocations that the students were more likely to make the most mistakes belonged to ‘verb + adverb’, and ‘adjective + noun’ lexical collocations.  Article visualizations

PROBLEMS IN VIETNAMESE-ENGLISH TRANSLATION OF RELATIVE CLAUSES FOR ENGLISH-MAJORED JUNIORS AT TAY DO UNIVERSITY, VIETNAM

Realistically, Vietnamese-English translation is not easy for Vietnamese students to master, and relative clauses are not typical in Vietnamese. Therefore, learners cannot avoid mistakes in their translation practice. Concerned researchers carried out a study to identify common Vietnamese-English translation errors in terms of English relative clauses. The participants were 60 juniors from the Bachelor of English course at Tay Do University. Test papers and interviews were employed as the instruments. The collected data from the two instruments mentioned above were all analyzed carefully afterward. The results of the study showed that the students suffered from a variety of grammar and vocabulary problems hindering them from translating Vietnamese into English correctly. Article visualizations