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106 results on '"Dang, Trung Dung"'

6. Purification of Spherical Graphite as Anode for Li-Ion Battery: A Comparative Study on the Purifying Approaches.

Author

Vu, Tri Thien, La, Duong Duc, Le, Long Vu, Pham, Trung Kien, Nguyen, Minh Anh, Nguyen, Tran Hung, Dang, Trung Dung, Um, Myoung-Jin, Chung, Woojin, and Nguyen, Dinh Duc

Subjects
SCANNING electron microscopy, LITHIUM-ion batteries, CYCLIC voltammetry, X-ray diffraction, SURFACE area
Abstract

Graphite is a versatile material used in various fields, particularly in the power source manufacturing industry. Nowadays, graphite holds a unique position in materials for anode electrodes in lithium-ion batteries. With a carbon content of over 99% being a requirement for graphite to serve as an electrode material, the graphite refinement process plays a pivotal role in the research and development of anode materials for lithium-ion batteries. This study used three different processes to purify spherical graphite through wet chemical methods. The spherical graphite after the purification processes was analysed for carbon content by using energy-dispersive X-ray (EDX) spectroscopy and was evaluated for structural and morphological characteristics through X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analyses. The analyses results indicate that the three-step process via H2SO4–NaOH–HCl cleaning can elevate the carbon content from 90% to above 99.9% while still maintaining the graphite structure and spherical morphology, thus enhancing the surface area of the material for anode application. Furthermore, the spherical graphite was studied for electrochemical properties when used as an anode for Li-ion batteries using cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) measurements. The results demonstrated that the purification process significantly improves the material's capacity with a specific capacity of 350 mAh/g compared to the 280 mAh/g capacity of the anode made of spherical graphite without purification. [ABSTRACT FROM AUTHOR]

Published
2024
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20. Apnoeic oxygenation with high‐flow oxygen for tracheal resection and reconstruction

Author

Nguyen Minh Ly, Tong Xuan Hung, Ngo Vi Hai, Dang Trung Dung, Dinh Thi Thu Trang, Nguyen Truong Tho, Nguyen Quang Truong, Dam Van Khai, Nguyen Quoc Khanh, and Ngo Van Dinh

Abstract

Objective: This study aimed to evaluate the effectiveness of high‐flow oxygen as the sole method of gas exchange in apnoeic conditions during anastomosis construction. Subject and method: Between April 2019 and August 2020, 16 patients with tracheal stenosis, ages ranging from 19 to 70, underwent tracheal resection and reconstruction. Patients received total anesthesia and neuromuscular blocking agents for the duration of their surgery. During the anastomosis phase using high flow oxygen of 35 - 40 l.min‐1 delivered across an open tracheal with an endotracheal tube (ETT) at the glottis in apnoeic conditions. Result: The mean (SD) apnoea time was 20.91 ± 2.53 mins. Mean (SD) time anastomosis was 22.9 ± 2.41 mins. The saturation of oxygen was stable during all procedures at 98-100%. One patient experienced an oxygen desaturation episode to a value between 88% and 90% lasting less than 2 mins. Arterial blood gas analysis showed that there was hypercapnia and acidosis acute respiratory with pH 7.25 ± 0.04; PaCO2 67.57 ± 14.71mmHg, and PaO2 167.12 ± 76.23mmHg after 10 mins of apnoea and pH was 7.17 ± 0.05; PaCO2 79.63 ± 13.39mmHg and PaO2 186.19 ± 60.14mmHg after 20 mins apnoea, respectively. However, after 15 mins of ventilation, the parameters are ultimately returned to normal. The blood pressure and heart rate are stable at times. All 16 patients were extubated early and safely at the end of the operation. There were no complications, such as bleeding, hemothorax, pneumothorax, or barotrauma. Conclusion: High-flow oxygen across an open tracheal under apnoeic conditions can provide a satisfactory gas exchange to allow tubeless anesthesia for tracheal resection and reconstruction. The surgical field is ultimately in spacious, optimal conditions for anastomosis.

Published
2021

29. Absorption Behavior of Graphene Nanoplates toward Oils and Organic Solvents in Contaminated Water

Author

La, Duong Duc, primary, Nguyen, Tuan Anh, additional, Nguyen, Thanh Tung, additional, Ninh, Ha Duc, additional, Thi, Hoai Phuong Nguyen, additional, Nguyen, Tham Thi, additional, Nguyen, Duy Anh, additional, Dang, Trung Dung, additional, Rene, Eldon R., additional, Chang, Soon Woong, additional, Thi, Hien Tran, additional, and Nguyen, Dinh Duc, additional

Published
2019
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31. Current Situation And Solutions On Labor Relations In Foreign Invested Enterprises (Fdi) In Ho Chi Minh City.

Author

Dang Trung Dung

Subjects
INDUSTRIAL relations, FOREIGN workers, INTERNATIONAL relations, FOREIGN investments, BUSINESS enterprises, ENTERPRISE resource planning
Abstract

Ho Chi Minh City has many favorable conditions for foreign invested enterprises (FDI) to invest. Labor relations in the foreign-invested sector at enterprises in Ho Chi Minh City is a necessary and urgent issue with the great significance in terms of both theory and practice, as a primary concern of employers and employees. Good handling of this relationship is also one of the important factors to attract foreign direct investment and enterprises in Ho Chi Minh City, so as to contribute to economic growth in the process of industrialization, modernization, increase budget revenue, increase export turnover, partly solving labor problems and economic restructure in the trend of global economic integration at the locality. However; besides the achieved results, the labor relations situation in enterprises still has many shortcomings, such as: reforming policies to attract foreign direct investment is still limited, the state management still has many shortcomings, not paying enough attention to the policy of encouraging employees, etc. Therefore, it is necessary to propose solutions to improve labor relations, enhancing the lives of workers in non-state enterprises, partly making healthy labor relations in foreign-invested enterprises in Ho Chi Minh City. [ABSTRACT FROM AUTHOR]

Published
2021

33. Degradation of glyphosate herbicide by an electro-Fenton process using carbon felt cathode.

Author

Tran, Manh Hai, Nguyen, Hoai Chau, Le, Thanh Son, Dang, Viet Anh Dung, Cao, The Ha, Le, Cao Khai, and Dang, Trung-Dung

Subjects
GLYPHOSATE, HERBICIDES, MICROBIAL fuel cells, TRANSCRANIAL direct current stimulation, HYDROXYL group, CATHODES, HYDROGEN peroxide, AQUEOUS solutions
Abstract

An electro-Fenton system, which consists of a Pt gauze anode and a commercial carbon felt cathode, is commonly employed to generate in situ hydrogen peroxide, hydroxyl radical and regenerate ferrous catalyst for glyphosate degradation (a widely used herbicide in Vietnam) in aqueous solution. The absorbance measurements used to determine the glyphosate concentration during the electrolysis proved that glyphosate was degraded by pseudo-first-order kinetic. The influence of pH, current density, catalyst concentration and initial content of the glyphosate on mineralisation efficiency were studied by monitoring the total organic carbon (TOC) and hydrogen peroxide concentration during electrolysis. The results show that the maximal removal percentage of glyphosate was 91.91% with applied current density of 10 mA cm−2, pH 3, 0.1 mM Fe2+, 0.05 M Na2SO4, and 0.1 mM glyphosate in 40 min. The degrading rate constant of glyphosate degradation was calculated to be kapp = 0.063 min−1. In this 91.91% removal, 81.65% of glyphosate was mineralised and the remainder consists of intermediates produced during the electro-Fenton process. [ABSTRACT FROM AUTHOR]

Published
2021
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50. Green synthesis of zero-valent iron nanoparticles by Cleistocalyx operculatusleaf extract using microfluidic device for degradation of the Rhodamine Bdye

Author

Van Hoang, Nguyen, Nguyen-Thi, Le, Kim, Gyu Man, Dang, Trung-Dung, Ngoc Toan, Vu, and La, Duong Duc

Abstract

Environmental pollution, in particular, the wastewater from the textile and dyeing production process is causing serious issues for the ecosystem and humans. It has been well-demonstrated that zero-valent iron nanoparticles (nZVI) are one of the most promising materials in the treatment of environmental pollutants. In this work, the Cleistocalyx operculatusleaf extract was employed as a green reductant for the synthesis of the nZVIs nanoparticles from iron ions precursor. Notably, a microfluidic device was also used as micro-reactor for the synthesis process of the nanoparticles, making it easy to control and optimise the morphologies and sizes of nZVI. The morphology and crystallinity of nZVI were characterised by scanning electron microscopy (SEM) and x-ray diffraction (XRD), respectively. The nZVIs prepared in a microfluidic reactor using Cleistocalyx operculatusleaf extract as reductant were in plate-like structure with the thickness of around 5 nm and the diameter in range of hundred nanometers. The removal efficiency of Rhodamin B (RhB) dye by the prepared nZVI was determined by ultraviolet-visible (UV–vis) spectroscopy. The results showed that the nZVI revealed high removal performance toward RhB with removal efficiency of higher than 90% after 30 min of treatment. The effects of dye’s concentration, time, and pH solution on the treatment performance of RhB were also studied.

Published
2022
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