Intercept probability analysis in DF time switching full-duplex relaying network with impact of Co-channel interference at the eavesdropper

In this research, we propose and investigate intercept probability analysis in DF time switching relaying full-duplex with impact of Co-channel interference at the eavesdropper. In the beginning stage, we present the DF time switching relaying full-duplex with the Impact of Co-channel interference at the eavesdropper. Furthermore, the closed-form expression of the intercept probability (IP) is analyzed and derived in connection with the primary system parameters. Finally, the Monte Carlo simulation is performed for verifying the correctness of the analytical section. From the research results, a novel solution and some recommendations can be proposed for the communication network in the near future

Secrecy performance of TAS/SC-based multi-hop harvest-to-transmit cognitive WSNs under joint constraint of interference and hardware imperfection

In this paper, we evaluate the secrecy performance of multi-hop cognitive wireless sensor networks (WSNs). In the secondary network, a source transmits its data to a destination via the multi-hop relaying model using the transmit antenna selection (TAS)/selection combining (SC) technique at each hop, in the presence of an eavesdropper who wants to receive the data illegally. The secondary transmitters, including the source and intermediate relays, have to harvest energy from radio-frequency signals of a power beacon for transmitting the source data. Moreover, their transmit power must be adjusted to satisfy the quality of service (QoS) of the primary network. Under the joint impact of hardware imperfection and interference constraint, expressions for the transmit power for the secondary transmitters are derived. We also derive exact and asymptotic expressions of secrecy outage probability (SOP) and probability of non-zero secrecy capacity (PNSC) for the proposed protocol over Rayleigh fading channel. The derivations are then verified by Monte Carlo simulations.Web of Science195art. no. 116

Performance of cluster-based cognitive multihop networks under joint impact of hardware noises and non-identical primary co-channel interference

In this paper, we evaluate outage probability (OP) of a cluster-based multi-hop protocol operating on an underlay cognitive radio (CR) mode. The primary network consists of multiple independent transmit/receive pairs, and the primary transmitters seriously cause co-channel interference (CCI) to the secondary receivers. To improve the outage performance for the secondary network under the joint impact of the CCI and hardware imperfection, we employ the best relay selection at each hop. Moreover, the destination is equipped with multiple antennas and uses the selection combining (SC) technique to enhance the reliability of the data transmission at the last hop. For performance evaluation, we first derive an exact formula of OP for the primary network which is used to calculate the transmit power of the secondary transmitters. Next, an exact closed-form expression of the end-to-end OP for the secondary network is derived over Rayleigh fading channels. We then perform Monte-Carlo simulations to validate the derivations. The results present that the CCI caused by the primary operations significantly impacts on the outage performance of the secondary network

Invited review. Bond dissociation enthalpies in benzene derivatives and effect of substituents: an overview of density functional theory (B3LYP) based computational approach

In this review, we have mainly focused on the recent computational studies on the bond dissociation enthalpies (BDE) of the X‒H bonds of the para and meta substituted benzene derivatives (3Y-C6H4X‒H and 4Y-C6H4X‒H with X = O, S, Se, NH, PH, CH2, SiH2 and Y = H, F, Cl, CH3, OCH3, NH2, CF3, CN, NO2). In addition, the remote substituent effects on the BDE(X‒H), the radical stability and parent one have also been discussed in terms of the calculated ground state effect, radical effect and total effect. Model chemistry of ROB3LYP/6-311++G(d,p)//B3LYP/6-311G(d,p) can reproduce the BDE values with the accuracy of 1.0‒2.0 kcal/mol. The good linear correlations between Hammett constants and BDE values were discovered for both para and meta substitutions in phenols, thiophenols, benzeneselenols, anilines and phenylposphines with the R-squared lager than 0.94. In contrast, it does not occur in case of toluenes and phenylsilanes.Keywords. Benzene derivatives, density functional theory, bond dissociation enthalpies, substituent effects, radical effect, ground state effect, total effect, Hammett constants

EFL Agreeing and Disagreeing Discourses in Facebook

Agreeing and disagreeing are two common speech acts that occur in social conversations. Driven by the fact that there are direct and indirect way for expressing agreement and disagreement, and there are also mitigating strategies to protect interlocutors from face-threatening in disagreeing discourses, this study examined EFL students’ use of discourse strategies in their Facebook interaction. Thirty-four pre-intermediate EFL students at a university in Vietnam took part in this study. Data analysis shows that direct discourses is linguistically limited while indirect ones exhibit wider language use. Students also demonstrate two different directions of using mitigating strategies for their disagreeing discourses. Some pedagogical implications are also suggested in this study. Keywords: agreeing, disagreeing, direct, indirect, strategies DOI: 10.7176/JLLL/86-03 Publication date: February 28th 202

KHẢ NĂNG ỨC CHẾ ĂN MÒN CỦA AMOXICILLIN TRÊN THÉP CÁC BON TRONG MÔI TRƯỜNG HCl 1 M

The corrosion inhibition of amoxicillin (AMO) on mild carbon steels in 1 M HCl acid solution was studied experimentally and with computational chemistry techniques. The inhibition efficiency increases with the concentration of AMO, reaching the maximal value (84.72%) at 100 mg·L–1 and 25°C. Several quantum chemical parameters were calculated based on the optimal configuration of AMO at the theoretical level of B3LYB/6-31+G(d,p). Molecular dynamics and Monte Carlo simulation were used to configure the most robust absorption configuration on the surface of Fe(110) and clarify the mechanism of the inhitition process. The results show that AMO is an effective corrosion inhibitor.Sự ức chế ăn mòn của amoxicillin (AMO) trên thép các bon nhẹ trong môi trường HCl 1 M đã được nghiên cứu bằng phương pháp thực nghiệm và hóa tính toán. Hiệu quả ức chế ăn mòn của AMO lên thép tăng lên khi tăng nồng độ AMO và đạt cực đại (84,72%) ở 25 °C và nồng độ AMO 100 mg·L–1. Một vài thông số hóa lượng tử được tính toán dựa trên cấu hình tối ưu của AMO ở mức ở mức lý thuyết B3LYP/6-31+G(d,p). Mô phỏng động lực học phân tử và mô phỏng Monte Carlo được ứng dụng để tìm cấu hình                               hấp phụ bền nhất của AMO trên bề mặt Fe(110) và làm rõ cơ chế của quá trình ức chế ăn mòn. Kết quả cho thấy AMO là một chất ức chế ăn mòn hiệu quả đối với thép các bon nhẹ trong dung dịch HCl 1 M

TURBIDITY REMOVAL BY MUCILAGE FROM BASELLA ALBA

Coagulation and flocculation are preliminary used in water treatment processes for turbidity removal, using popularily synthetic chemicals with health and environmental concerns. The use of natural flocculants has known to be a promising alteratives for chemical ones due to their environmental friendly behavior. This research investigated turbidity removal efficiency of mucilage extracted from Basella alba - an indigenous species in Vietnam - in the role of a flocculant. The removal efficiency of mucilage was investigated in combination with PAC or Alum on To Lich river water by mean of Jar tests. PAC or Alum alone can remove maximum 97% and 90% turbidity of To Lich river water at its original pH for the sedimentation time of 30 minutes. The combination of mucilage and PAC or Alum increased the efficiencies of turbidity removal and reduced the amount of chemicals needed. The corresponding increases were maximum 7% and 18%, respectively; while the reduction of PAC/Alum used was 75-80%

Application of Google Docs in English for Specific Purposes Collaborative Writing

English language learners today have considerable opportunities to practice their writing skill via their peer interaction in Web 2.0 platforms, such as Blogs, Wikis, and Google Docs. Different studies have investigated the influence of these platforms on student writing collaboration and interaction, but few studies had explored factors that may affect English for Specific Purposes (ESP) student collaborative writing in Vietnamese settings. This study, therefore, attempts to explore the impact of four factors, namely gender, student attitudes towards learning English, student economic status, and availability of English at home on Google Docs-based interaction and collaborative writing outcome at a southern university in Vietnam. Fifty participants took part in this study and they worked collaboratively in small groups in Google Docs to finish two writing tasks and complete a survey afterwards. Analysis of their survey, interaction, and writing outcome suggests that gender, student attitudes towards learning English, and the number of books available at their homes have an impact on their writing outcome whereas their economic status did not seemingly affect their writing quality. Some pertinent pedagogical implications are also discussed in this paper. Keywords: Google Docs, collaborative writing, English for Specific Purposes DOI: 10.7176/JLLL/78-02 Publication date: April 30th 202