Effect of Al on the Microstructure and Mechanical Properties of Mg–Sn–Ca–Mn Wrought Alloy

Yun Feng,Yuanyuan Yang,Zongqi Xiao,Xianglong Meng,Guorong Zhou,Jinfeng Leng,Xinying Teng 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

Mg–Sn–Ca–Mn–xAl (x = 0,1.5 wt%) alloys with ultra-fine recrystallized grains were prepared by conventional extrusion(400 °C, 0.5 mm/s). Effects of aluminum (Al) on mechanical properties and microstructure of the Mg–1Sn–1Ca–0.5Mn(wt%) alloy were systematically investigated. By the addition of 1.5 wt% Al, the yield strength of the as-extruded alloysignificantly increased from 183 to 237 MPa. The as-cast alloys show a dendritic structure consists of α-Mg, (Mg, Al)2Ca,and CaMgSn phases. The as-extruded Mg–1Sn–1Ca–0.5Mn–1.5Al alloys exhibit a bimodal grain structure composed ofdynamic recrystallized (DRXed) fine grains and coarse unDRXed grains. Compared with Al free alloy, a lot of nano-scaleplanar Al2Caand rectangle shape Al8Mn5precipitated in the as-extruded alloy with 1.5 wt% Al. Meanwhile, the addition ofAl significantly strengthened alloys’ fiber texture with < 10–10 >//ED.

The Effectiveness of Extensive Reading on EFL Learners’ Vocabulary Learning : Incidental versus Intentional Learning

Feng Teng 부산외국어대학교 외국어연구소 2015 외국어연구 Vol.28 No.-

The Effectiveness of Extensive Reading on EFL Learners’ Vocabulary Learning: Incidental versus Intentional Learning Feng Teng Forty-six students majoring in business English volunteered to take part in an extensive reading program. The learners were divided into two groups: EG, the experimental group, received instruction in methods of extensive reading plus explicit outputpushed activities, and CG, the control group, received instruction in methods of extensive reading alone. This study measured the effects of extensive reading on EFL vocabulary learning, as well as the effect of the two different instruction methods on learning receptive and productive vocabulary for the 46 learners of different vocabulary size. The research found that (a) both the two instructional methods resulted in significant gains in learners’ receptive and productive vocabulary knowledge, but the combination of the incidental and intentional learning instruction yields greater vocabulary gains; (b) only 91.8% of receptive vocabulary is understood productively; and (c) students’ vocabulary size plays a decisive role in acquiring the receptive and productive aspect of vocabulary knowledge (150 words). Key words: Incidental learning, intentional learning, Receptive vocabulary, productive vocabulary, extensive reading

Flipping the Classroom and Tertiary Level EFL Students’ Academic Performance and Satisfaction

Mark Feng Teng 아시아영어교육학회 2017 The Journal of Asia TEFL Vol.14 No.4

This study attempts to measure the possible impact that flipped teaching has had on the improvement of learners’ academic performance, as well as their satisfaction in a cross-cultural communication course. A total of 90 students learning English as a foreign language (EFL) were assigned to three conditions: a structured flipped classroom using a WebQuest active learning strategy, a semi-structured flipped classroom, and a traditional classroom. Results showed that the structured flip lessons were the most effective instructional intervention in improving participants’ academic performance, followed by the semi-structured flip lessons and the traditional lessons. Data collected from the questionnaire and interviews indicated that learners were more satisfied with the structured flip lessons than the semi-structured flip lessons. Given the positive results, the present study argues that the flipped classroom model could be a useful and promising pedagogical approach in EFL teaching. However, additional research is needed to contribute to the knowledge base of this approach across disciplines.

An Approach for Security Problems in Visual Surveillance Systems by Combining Multiple Sensors and Obstacle Detection

Teng, Zhu,Liu, Feng,Zhang, Baopeng,Kang, Dong-Joong The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

As visual surveillance systems become more and more common in human lives, approaches based on these systems to solve security problems in practice are boosted, especially in railway applications. In this paper, we first propose a robust snag detection algorithm and then present a railway security system by using a combination of multiple sensors and the vision based snag detection algorithm. The system aims safety at several repeatedly occurred situations including slope protection, inspection of the falling-object from bridges, and the detection of snags and foreign objects on the rail. Experiments demonstrate that the snag detection is relatively robust and the system could guarantee the security of the railway through these real-time protections and detections.

말단 수산화기를 가진 폴리락타이드와 이미다졸로 블록된 이소시아네이트를 이용한 폴리우레탄 바이오접착제의 합성 및 물성 평가

Teng Fei Shen,Ying Juan Sun,Chun Feng Sun,Man Geng Lu 한국고분자학회 2013 폴리머 Vol.37 No.2

A series of novel imidazole-blocked diisocyanate bioadhesives (IBAs) were synthesized from reaction of toluene 2, 4-diisocyanate (TDI), isophorone diisocyanate (IPDI), hydroxyl-terminated polylactide (HO-PLA-OH), 1,1,1-trimethylolpropane (TMP), and imidazole. Synthesis of IBAs was confirmed by Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) revealed that the TDI-based IBA had lower thermal dissociation temperature and a faster deblocking rate than IBA based on IPDI. Hydroxyl-terminated polyurethane (HPU) was introduced to study the adhesive effect of the synthesized IBAs. Improvement on elastic modulus, tensile strength and water resistance of IBA-modified HPU in comparison with neat HPU suggested the good adhesive effect of IBA due to the strong chemical reaction between released NCO groups from IBA and hydroxyl groups from HPU.

Value of Ultrasound Elastography in Assessment of Enlarged Cervical Lymph Nodes

Teng, Deng-Ke,Wang, Hui,Lin, Yuan-Qiang,Sui, Guo-Qing,Guo, Feng,Sun, Li-Na Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Background: To investigate the value of ultrasound elastography (UE) in the differentiation between benign and malignant enlarged cervical lymph nodes (LNs). Methods: B-mode ultrasound, power Doppler imaging and UE were examined to determine LN characteristics. Two kinds of methods, 4 scores of elastographic classification and a strain ratio (SR) were used to evaluate the ultrasound elastograms. Results: The cutoff point of SR had high utility in differential diagnosis of benign and malignant of cervical lymph nodes, with good sensitivity, specificity and accuracy. Conclusion: UE is an important aid in differential diagnosis of benign and malignant cervical LNs.

Paleoenvironmental changes of source rocks from the Carboniferous to Permian sediments of the Mahu Sag, Junggar Basin, China

Feng Chong,Ma Mingze,He Wenjun,Li Teng,Wu Qiuyu,Zhang Zexin,Zhao Haiyang 한국자원공학회 2020 Geosystem engineering Vol.23 No.5

There are four sets of source rocks from Carboniferous (C) to Permian in Mahu Sag, and the paleoenvironment is the decisive factor for the differences of source rocks. In order to study the controlling effect of paleoenvironmental evolution on the change of source rock properties, the major, trace elements and the total organic carbon (TOC) of 47 core samples from four sets of source rocks were tested. The results indicate that the paleoenvironmental evolution of these four sets of source rocks from C to Permian in Mahu Sag can be divided into five stages. At the end of C and the early stage of deposition of Wuerhe formation (P2w), the paleo climate became warm and humid, and the salinity of water body became small. Meanwhile, the oxidizability of water body gradually became stronger. At the deposition stage of Jiamuhe Formation (P1j), Fengcheng Formation (P1f) and the late stage of deposition of P2w, the paleo climate gradually became hot and dry, and the salinity of water body gradually increased. Meanwhile, the reducibility of water body became stronger. The paleoenvironmental factors controlling the abundance of organic matter in source rocks are different in different stages.

Experimental Evaluation of Accelerated T1rho Relaxation Quantification in Human Liver Using Limited Spin-Lock Times

Feng Zhao,Min Deng,Jing Yuan,Gao-Jun Teng,Anil T Ahuja,Yi-Xiang J. Wang 대한영상의학회 2012 Korean Journal of Radiology Vol.13 No.6

Objective: It was reported lately that to obtain consistent liver T1rho measurement, at 3T MRI using six spin-lock times (SLTs), is feasible. In this study, the feasibility of using three or two SLT points to measure liver T1rho relaxation time was explored. Materials and Methods: Seventeen healthy volunteers underwent 36 examinations. Three representative axial slices were selected to cut through the upper, middle, and lower liver. A rotary echo spin-lock pulse was implemented in a 2D fast field echo sequence. Spin-lock frequency was 500 Hz and the spin-lock times of 1, 10, 20, 30, 40, and 50 milliseconds (ms) were used for T1rho mapping. T1rho maps were constructed by using all 6 SLT points, three SLT points of 1, 20, and 50 ms, or two SLTs of 1 and 50 ms, respectively. Intra-class correlation coefficient (ICC) and Bland and Altman plot were used to assess the measurement agreement. Results: Two examinations were excluded, due to motion artifact at the SLT of 50 ms. With the remaining 34 examinations, the ICC for 6-SLT vs. 3-SLT T1rho measurements was 0.922, while the ICC for 6-SLT vs. 2-SLT T1rho measurement was 0.756. The Bland and Altman analysis showed a mean difference of 0.19 (95% limits of agreement: -1.34, 1.73) for 6-SLT vs. 3-SLT T1rho measurement, and the mean difference of 0.89 (95% limits of agreement: -1.67, 3.45) for 6-SLT vs. 2-SLT T1rho measurement. The scan re-scan reproducibility ICC (n = 11 subjects) was 0.755, 0.727, and 0.528 for 6-SLT measurement, 3-SLT measurement, and 2-SLT measurement, respectively. Conclusion: Adopting 3 SLTs of 1, 20, and 50 ms can be an acceptable alternative for the liver T1rho measurement, while 2 SLTs of 1 and 50 ms do not provide reliable measurement. Objective: It was reported lately that to obtain consistent liver T1rho measurement, at 3T MRI using six spin-lock times (SLTs), is feasible. In this study, the feasibility of using three or two SLT points to measure liver T1rho relaxation time was explored. Materials and Methods: Seventeen healthy volunteers underwent 36 examinations. Three representative axial slices were selected to cut through the upper, middle, and lower liver. A rotary echo spin-lock pulse was implemented in a 2D fast field echo sequence. Spin-lock frequency was 500 Hz and the spin-lock times of 1, 10, 20, 30, 40, and 50 milliseconds (ms) were used for T1rho mapping. T1rho maps were constructed by using all 6 SLT points, three SLT points of 1, 20, and 50 ms, or two SLTs of 1 and 50 ms, respectively. Intra-class correlation coefficient (ICC) and Bland and Altman plot were used to assess the measurement agreement. Results: Two examinations were excluded, due to motion artifact at the SLT of 50 ms. With the remaining 34 examinations, the ICC for 6-SLT vs. 3-SLT T1rho measurements was 0.922, while the ICC for 6-SLT vs. 2-SLT T1rho measurement was 0.756. The Bland and Altman analysis showed a mean difference of 0.19 (95% limits of agreement: -1.34, 1.73) for 6-SLT vs. 3-SLT T1rho measurement, and the mean difference of 0.89 (95% limits of agreement: -1.67, 3.45) for 6-SLT vs. 2-SLT T1rho measurement. The scan re-scan reproducibility ICC (n = 11 subjects) was 0.755, 0.727, and 0.528 for 6-SLT measurement, 3-SLT measurement, and 2-SLT measurement, respectively. Conclusion: Adopting 3 SLTs of 1, 20, and 50 ms can be an acceptable alternative for the liver T1rho measurement, while 2 SLTs of 1 and 50 ms do not provide reliable measurement.

An Approach for Security Problems in Visual Surveillance Systems by Combining Multiple Sensors and Obstacle Detection

Zhu Teng,Feng Liu,Baopeng Zhang,Dong-Joong Kang 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.3

As visual surveillance systems become more and more common in human lives, approaches based on these systems to solve security problems in practice are boosted, especially in railway applications. In this paper, we first propose a robust snag detection algorithm and then present a railway security system by using a combination of multiple sensors and the vision based snag detection algorithm. The system aims safety at several repeatedly occurred situations including slope protection, inspection of the falling-object from bridges, and the detection of snags and foreign objects on the rail. Experiments demonstrate that the snag detection is relatively robust and the system could guarantee the security of the railway through these real-time protections and detections.

Performance evaluation on vacuum pumps using nanolubricants

Yeou-Feng Lue,Yu-Chun Hsu,Tun-Ping Teng 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.9

This study produced alumina (Al 2 O 3 ) nanovacuum-pump lubricants (NVALs) by involving the dispersion of Al 2 O 3 nanoparticles in a vacuum-pump lubricant (VAL) with oleic as a dispersant. Experiments were conducted to evaluate the suspension performance, thermal conductivity, viscosity, specific heat, tribological performance and vacuum-pump performance of the NVALs. The experimental results obtained from the vacuum-pump performance tests show that the NVALs with Al 2 O 3 concentration of 0.2 wt.% and oleic concentration of 0.025 wt.% yielded the lowest electricity consumption, conserving 2.39% of electricity compared with the VAL. No marked difference was observed between the temperatures of the vacuum pump using VAL and NVAL. Furthermore, evacuation (i.e., the minimal pressure of -99.5 kPa) was reached faster by the vacuum pump with the NVALs, and the evacuation time could be reduced by 4.91% under optimal conditions. In addition, the vacuum pump with the NVALs exhibited superior overall effectiveness under relatively lower ambient temperatures.