Effect of oxidation of SiC particles on mechanical properties and wear behavior of SiC_p/Al6061 composites

Van Trinh, Pham,Lee, Junho,Minh, Phan Ngoc,Phuong, Doan Dinh,Hong, Soon Hyung Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.769 No.-

<P><B>Abstract</B></P> <P>In this paper, oxidized-silicon carbide particle/aluminum 6061 (oxidized-SiC<SUB>p</SUB>/Al6061) composites were fabricated using a spark plasma sintering technique. The microstructure, mechanical properties, and wear behavior of oxidized-SiC<SUB>p</SUB>/Al6061 composites were investigated. The results revealed an improvement in interfacial bond strength between Al6061 and oxidized SiC<SUB>p</SUB> due to the formation of an MgAl<SUB>2</SUB>O<SUB>4</SUB> continuous phase and suppression of brittle Al<SUB>4</SUB>C<SUB>3</SUB> formation at the interfacial layer. Hardness (∼145 HV), ultimate tensile strength (∼226 MPa), and elongation (10.8%) were enhanced by 75%, 26%, and 32%, respectively, for the composite containing 1400°C-oxidized SiC<SUB>p</SUB>, compared with those reinforced with as-received SiC<SUB>p</SUB>. The friction coefficient and specific wear rate of oxidized-SiC<SUB>p</SUB>/Al6061 composites were reduced by 7% and 17%, respectively; this is attributable to the improved hardness and strength of the composite and the transition of wear mechanisms from a combination of adhesive and fatigue wear to abrasive wear. Quantitative correlations among yield strength, ultimate tensile strength, and interfacial bond strength in SiC<SUB>p</SUB>/Al6061 composites were analyzed for the first time.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Oxidized-SiC<SUB>p</SUB>/Al6061 composites were prepared by spark plasma sintering. </LI> <LI> Interfacial layer between oxidized-SiC<SUB>p</SUB> and Al6061 matrix was investigated. </LI> <LI> The interfacial bond strength between oxidized SiC<SUB>p</SUB> and Al6061 matrix was estimated. </LI> <LI> Mechanical properties and wear resistance of the composites were improved. </LI> <LI> New quantitative correlations among the strengths of the composites was analyzed. </LI> </UL> </P>

Chemical components from the leaves of Ardisia insularis and their cytotoxic activity

Nguyen Thi Hong Van,김승현,Trinh Anh Vien,Phan Van Kiem,Chau Van Minh,Nguyen Xuan Nhiem,Pham Quoc Long,Luu Tuan Anh,김난영,박선주 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.11

One new oleanane triterpene glycoside, ardinsuloside(1), and twelve known compounds, demethoxybergenin(2), norbergenin (3), bergenin (4), 4-O-galloylbergenin(5), quercitrin (6), myricitrin (7), myricetin 3-O-(300-O-galloyl)-a-L-rhamnopyranoside (8), desmanthine-2 (9), epicatechin3-O-galloyl ester (10), 30-methoxyepicatechin 3-Ogalloylester (11), gallic acid (12), and methyl galloate (13)were isolated from the leaves of Ardisia insularis. Theirstructures were established on the basis of spectral and chemicalevidence, which were in agreement with those reportedin literature. The cytotoxic activities of these compounds wereevaluated on three cancer cell lines namely A-549 (humanlung cancer), HT-29 (Human colon adenocarcinoma), andOVCAR (human ovarian carcinoma). The results revealedthat compound 1 inhibited A-549, HT-29, and OVCAR celllines with IC50 values of 8.5 ± 1.2, 16.4 ± 3.1, and13.6 ± 2.4 lM, respectively. The remaining compoundshowed weak cytotoxic activity. This result indicated thatcompound 1 could be useful in the treatment of cancer disease.

Light-Induced Absorption and Holographic Recording in Pr:LiNbO3

Van-Thai Pham,임기수,D. S. Hamilton,Minh-Tuan Trinh,이선균 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.2I

With ultraviolet illumination, we have found a broad UV-induced absorption in the blue and some involvement of Pr ions in Pr:LiNbO3. Transient and stable absorption induced by UV illumination was analyzed at 457, 514, and 633 nm and could be explained by hole trap centers and iron ions. We also studied the effects of UV illumination and boundary conditions during holographic recording in the visible. In ultraviolet-gated short-circuit holographic recording, we obtained a high sensitivity and a high diffraction efficiency.

Two Human Cases of Echinococcus ortleppi Infection in the Lung and Heart in Vietnam

Nguyen Van De,Pham Ngoc Minh,Le Van Duyet,Nguyen Ngoc Bich,Trinh Nam Son,정봉광,채종일 대한기생충학ㆍ열대의학회 2020 The Korean Journal of Parasitology Vol.58 No.4

This is a report of 2 cases of human hydatidosis caused by Echinococcus ortleppi in Vietnam. The patients were a 12-year-old male (case 1) having a cyst of 10.0×9.0 cm size in the lung and a 50-year-old female with a 3.0×3.3 cm-sized cyst in the heart. Eosinophilia was 33.7% in the male and 45.8% in the female patient. C-reactive protein was increased to 16.5 mg/L in the male and 18.2 mg/L in the female. Both patients were positive for ELISA at OD=2.5 and 3.1, respectively. Echinococcus protoscolices were collected from the cysts by amniocentesis and surgery. The protoscolices were identified as E. ortleppi by morphology and analysis of mitochondrial NADH dehydrogenase 1 (nad1) gene sequence. Both patients were cured by surgical resection of the hydatid cyst combined with albendazole medication. The E. ortleppi infection in lung is the second report, and the other in the heart is the first in Vietnam.

Access to Anti-smoking Information among School Children and its Potential Impact on Preventing Smoking Initiation: Results from the Global Youth Tobacco Use Survey (GYTS) 2014 in Viet Nam

Hoang, Van Minh,Kim, Bao Giang,Phan, Thi Hai,Trinh, Dinh Hoang,Doan, Thu Huyen,Luong, Ngoc Khue,Nguyen, Thuy Linh,Nguyen, Tuan Lam,Pham, Thi Quynh Nga Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.no.sup1

Scientific evidence on all aspects of smoking amongst youth is very important for designing appropriate interventions to reduce smoking among this vulnerable population. This paper describes current access to anti-smoking information among school children aged 13 to 15 years in Vietnam in 2014 and examines its potential impact on preventing smoking initiation. The data used in this paper were obtained from the 2014 Global Youth Tobacco Survey (GYTS) in Vietnam. Students were asked questions about their level of awareness of anti-smoking information from various sources in the past 30 days and about lessons in school regarding the dangers of tobacco use during the last 12 months. Those who have never smoked were asked "whether or not they thought about avoiding cigarettes because of health warnings on cigarette packages" and answers were analyzed in combination with data on access to anti-smoking information from other sources. The prevalence of exposure to antismoking campaigns was high among school children in Viet Nam: 55.3% of current smokers reported thoughts of smoking cessation because of health warnings on cigarette packages; 60.5% of never smokers avoided initiating smoking because of the same health warnings. The potential impact of graphic health warnings to prevent school-aged children from smoking initiation would be stronger if there was concurrent access to anti-smoking programs on the dangers of tobacco use in schools. However, school education for tobacco prevention and control has not been as strong as expected. A more comprehensive school curriculum on tobacco prevention and control is recommended to reinforce antismoking messages among school children.

Remaining Useful Life Estimation based on Noise Injection and a Kalman Filter Ensemble of modified Bagging Predictors

Hung-Cuong Trinh,Van-Huy Pham,Anh H. Vo 한국인터넷정보학회 2023 KSII Transactions on Internet and Information Syst Vol.17 No.12

Ensuring reliability of a machinery system involve the prediction of remaining useful life (RUL). In most RUL prediction approaches, noise is always considered for removal. Nevertheless, noise could be properly utilized to enhance the prediction capabilities. In this paper, we proposed a novel RUL prediction approach based on noise injection and a Kalman filter ensemble of modified bagging predictors. Firstly, we proposed a new method to insert Gaussian noises into both observation and feature spaces of an original training dataset, named GN-DAFC. Secondly, we developed a modified bagging method based on Kalman filter averaging, named KBAG. Then, we developed a new ensemble method which is a Kalman filter ensemble of KBAGs, named DKBAG. Finally, we proposed a novel RUL prediction approach GN-DAFC-DKBAG in which the optimal noise-injected training dataset was determined by a GN-DAFC-based searching strategy and then inputted to a DKBAG model. Our approach is validated on the NASA C-MAPSS dataset of aero-engines. Experimental results show that our approach achieves significantly better performance than a traditional Kalman filter ensemble of single learning models (KESLM) and the original DKBAG approaches. We also found that the optimal noise-injected data could improve the prediction performance of both KESLM and DKBAG. We further compare our approach with two advanced ensemble approaches, and the results indicate that the former also has better performance than the latters. Thus, our approach of combining optimal noise injection and DKBAG provides an effective solution for RUL estimation of machinery systems.

Heat Dissipation for the Intel Core i5 Processor Using Multiwalled Carbon-nanotube-based Ethylene Glycol

Bui Hung Thang,Pham Van Trinh,Le Dinh Quang,Nguyen Thi Huong,Phan Hong Khoi,Phan Ngoc Minh 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.3

Carbon nanotubes (CNTs) are some of the most valuable materials with high thermal conductivity. The thermal conductivity of individual multiwalled carbon nanotubes (MWCNTs) grown byusing chemical vapor deposition is 600 ± 100 Wm−1K−1 compared with the thermal conductivity419 Wm−1K−1 of Ag. Carbon-nanotube-based liquids – a new class of nanomaterials, have shownmany interesting properties and distinctive features offering potential in heat dissipation applicationsfor electronic devices, such as computer microprocessor, high power LED, etc. In this work,a multiwalled carbon-nanotube-based liquid was made of well-dispersed hydroxyl-functional multiwalledcarbon nanotubes (MWCNT-OH) in ethylene glycol (EG)/distilled water (DW) solutionsby using Tween-80 surfactant and an ultrasonication method. The concentration of MWCNT-OHin EG/DW solutions ranged from 0.1 to 1.2 gram/liter. The dispersion of the MWCNT-OH-basedEG/DW solutions was evaluated by using a Zeta-Sizer analyzer. The MWCNT-OH-based EG/DWsolutions were used as coolants in the liquid cooling system for the Intel Core i5 processor. Thethermal dissipation efficiency and the thermal response of the system were evaluated by directlymeasuring the temperature of the micro-processor using the Core Temp software and the temperaturesensors built inside the micro-processor. The results confirmed the advantages of CNTs inthermal dissipation systems for computer processors and other high-power electronic devices.

Impact of EVFTA on Trade Flows of Fruits between Vietnam and the EU

Duc Trong TRAN,Van Thu BUI,Ngoc Minh VU,Tung Son PHAM,Hue Minh TRUONG,Thuy Thu DANG,Tu Van TRINH 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.5

The European Union Vietnam Free Trade Agreement (EVFTA) took effect on August 1 paving the way for increased trade between the EU and Vietnam; this marked a huge turning point for the Vietnamese economy. Agriculture products, especially fruits, must be listed when it comes to Vietnam export industries that profit the most from EVFTA. After a period of study, with the desire to contribute to the improvement in the efficiency of Vietnam’s agricultural products to the EU, the researchers want to assess the impact of the EVFTA on the flows of Vietnamese fruits to the EU market. The study uses a quantitative analysis method via the WITS-SMART model with data on export turnover and tariff reductions in parallel with the analysis of changes in factors affecting the trade flows of fruits between the two markets when the EVFTA takes effect. As a result, Vietnam’s fruit importing from the EU is expected to escalate by 29.18% in 2021, while the flow of export will only inch up by 0.955%, which is rather low compare to the increase in import value. Hence, effective policies must be introduced in Vietnam to innovate production methods and increase product quality, so that the EVFTA can be used to boost Vietnam’s fruit exports to the EU.

Triterpenoids from aerial parts of Glochidion eriocarpum.

Thu, Vu Kim,Kiem, Phan Van,Yen, Pham Hai,Nhiem, Nguyen Xuan,Tung, Nguyen Huu,Cuong, Nguyen Xuan,Minh, Chau Van,Huong, Hoang Thanh,Lau, Trinh Van,Thuan, Ngo Thi,Kim, Young Ho Natural Product Communications 2010 Natural product communications Vol.5 No.3

<P>From the aerial parts of Glochidion eriocarpum, a new triterpene, glochieriol (1), three new triterpenoid saponins, glochieriosides C - E (2 - 4), together with four known triterpenes (glochidonol, glochidiol, lupeol, and 3-epi-lupeol) were isolated by using combined chromatographic separations. The structures of the new compounds were elucidated on the basis of spectroscopic data, including FTICR-MS, 1D and 2D NMR.</P>

Pancreaticoduodenectomy with superior mesenteric artery first-approach combined total meso-pancreas excision for periampullary malignancies: A high-volume single-center experience with short-term outcomes

Thanh Khiem Nguyen,Ham Hoi Nguyen,Tuan Hiep Luong,Kim Khue Dang,Van Duy Le,Duc Dung Tran,Van Minh Do,Hong Quang Pham,Hoan My Pham,Thi Lan Tran,Cuong Thinh Nguyen,Hong Son Trinh,Yosuke Inoue 한국간담췌외과학회 2024 Annals of hepato-biliary-pancreatic surgery Vol.28 No.1

Backgrounds/Aims: Pancreaticoduodenectomy (PD) is the only radical treatment for periampullary malignancies. Superior mesenteric artery (SMA) first approach combined with total meso-pancreas (MP) excision was conducted to improve the oncological results. There has not been any previous research of a technique that combines the SMA first approach and total MP excision with a detailed description of the MP macroscopical shape. Methods: We prospectively assessed 77 patients with periampullary malignancies between October 2020 and March 2022 (18 months). All patients had undergone PD with SMA first approach combined total MP excision. The perioperative indications, clinical data, intra-operative index, R0 resection rate of postoperative pathological specimens (especially mesopancreatic margin), postoperative complications, and follow-up results were evaluated. Results: The median operative time was 289.6 min (178−540 min), the median intraoperative blood loss was 209 mL (30−1,600 mL). Microscopically, there were 19 (24.7%) cases with metastatic MP, and five cases (6.5%) with R1-resection of the MP. The number of lymph nodes (LNs) harvested and metastatic LNs were 27.2 (maximum was 74) and 1.8 (maximum was 16), respectively. Some (46.8%) patients had pancreatic fistula, but mostly in grade A, with 7 patients (9.1%) who required re-operations. Some 18.2% of cases developed postoperative refractory diarrhea. The rate of in-hospital mortality was 1.3%. Conclusions: The PD with SMA first approach combined TMpE for periampullary malignancies was effective in achieving superior oncological statistics (rate of MP R0-resection and number of total resected LNs) with non-inferior short-term outcomes. It is necessary to evaluate survival outcomes with long-term follow-up.