Highly stable metal-organic framework templated N-doped bimetallic electrocatalysts for bifunctional water splitting reaction

Phuc Tran Van,Hur Seung Hyun 한국물리학회 2023 Current Applied Physics Vol.50 No.-

Bifunctional water-splitting electrocatalysts were synthesized by the pyrolysis of bimetallic metal-organic frameworks. The as-synthesized catalyst exhibited very low overpotentials of 261 mV for the oxygen evolution reaction (OER) and 101 mV for the hydrogen evolution reaction (HER) at 10 mA cm-2 in the 1.0 M KOH. The well-developed porous structure and conductive sp2 networks during pyrolysis might enhance the electrocatalytic activity. The computational simulation also showed that the formation of ZnN3 and NiN3 complexes by N-doping during the pyrolysis lowered the adsorption energies and accelerated the water-splitting kinetics. The as-prepared catalysts exhibited no current drops even after 3000 cycles of both OER and HER. Instrumental analysis also confirmed the excellent long-term stability after 3000 cycles.

Highly CO selective Ca and Zn hybrid metal-organic framework electrocatalyst for the electrochemical reduction of CO2

Van Phuc Tran,강성구,정진석,허승현 한국물리학회 2021 Current Applied Physics Vol.27 No.-

A transition metal (Zn) and alkaline earth metal (Ca)-hybridized metal-organic framework (MOF) based electrocatalyst was synthesized using a one-pot process. The as-prepared ZnCa-MOF74 (ZC) catalyst exhibited a low overpotential, an excellent CO selectivity, and high stability in the electrochemical reduction of CO2 (ERC). The Faradaic efficiency of ZC towards CO was as high as 93%, which is two times higher than that of the Zn-MOF74 catalyst. The computational simulation also showed that Ca lowered the activation barrier of the ratedetermining step during the ERC.

Brand Anthropomorphism, Brand Reputation, and Consumer Engagement in the Distribution of Smartphone Brands

Ngoc Dan Thanh NGUYEN(Ngoc Dan Thanh NGUYEN ),Trong Phuc NGO(Trong Phuc NGO ),Ngoc Van MAI(Ngoc Van MAI ),Kim Ngan TRA(Kim Ngan TRA ),Tran Huy Hoang LE(Tran Huy Hoang LE ) 한국유통과학회 2023 유통과학연구 Vol.21 No.4

Purpose: This study aims to analyze the impact of Brand Anthropomorphism and Intimacy on Brand Engagement, and at the same time analyze the regulatory effect of Brand Reputation on the relationship between Brand Anthropomorphism and Intimacy and the relationship between Intimacy and Brand Engagement in terms of distribution brand. Results: The findings show that Brand Anthropomorphism, Intimacy, and Brand Reputation are important value factors in customers’ minds toward their behavior, and from there, they will contribute to creating positive emotions and interactions between consumers and brands. Research design, data, and methodology: This article used the quantitative technique utilizing PLS-SEM software to test the hypothesis with 1,060 samples. Collected data shows that consumers in Ho Chi Minh City have positive emotions and interactive and social behaviors toward smartphone brands. Conclusion: The study has demonstrated the conclusions and proposed solutions to help smartphone brands build Brand Anthropomorphism while enhancing Brand Reputation thereby achieving Intimacy, which leads to consumer Brand Engagement. In addition, this study complements the concept of Brand Anthropomorphism which is lacking in theoretical background and is the first study in Vietnam to explore the prefixes and suffixes of the concept of Brand Anthropomorphism and the regulatory role of Brand Reputation.

Grain-Size Effect on the Dielectric Properties of La1.5Sr0.5NiO₄ Nano-Particle Materials

Tran Dang Thanh,Le Van Hong,Nguyen Xuan Phuc 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.6

We have manufactured ceramic samples of La1.5Sr0.5NiO₄and studied their dielectric proper-ties. The samples were prepared by using a reactive mechanical milling technique on D8000-Spex combined with an annealing at a temperature in the range of 700 ℃ - 1000 ℃. The crystalline structure and the sample's purity were checked by means of X-ray diffraction (XRD) on a SIEMENS D5000 spectrograph. The obtained XRD patterns conrmed that all the samples belonged to the F4K2Ni perovskite layer tetragonal structure with a space group of I4/mmm (139). The grain size of a ceramic sample was estimated based on the Field-emission scanning electron microscopy (FE- SEM) images and was calculated by using the Warren-Averbach method based on the Full Width at Half Maximum (FWHM) of the XRD lines. The results obtained by using the two methods were quite the same. The mean grain size (< D >) of the samples varied from 16.2 nm to 95 nm with the annealing temperature. Dielectric constant (ε) of all the samples was estimated from the capacitance measurement at different temperatures in the frequency range of 1 kHz - 13 MHz. The estimated ε of all the samples was about 105 over the whole frequency range up to 1 MHz. The temperature and the frequency dependences of ε(f T), the dielectric constant, were observed and are discussed for all the samples. We have manufactured ceramic samples of La1.5Sr0.5NiO₄and studied their dielectric proper-ties. The samples were prepared by using a reactive mechanical milling technique on D8000-Spex combined with an annealing at a temperature in the range of 700 ℃ - 1000 ℃. The crystalline structure and the sample's purity were checked by means of X-ray diffraction (XRD) on a SIEMENS D5000 spectrograph. The obtained XRD patterns conrmed that all the samples belonged to the F4K2Ni perovskite layer tetragonal structure with a space group of I4/mmm (139). The grain size of a ceramic sample was estimated based on the Field-emission scanning electron microscopy (FE- SEM) images and was calculated by using the Warren-Averbach method based on the Full Width at Half Maximum (FWHM) of the XRD lines. The results obtained by using the two methods were quite the same. The mean grain size (< D >) of the samples varied from 16.2 nm to 95 nm with the annealing temperature. Dielectric constant (ε) of all the samples was estimated from the capacitance measurement at different temperatures in the frequency range of 1 kHz - 13 MHz. The estimated ε of all the samples was about 105 over the whole frequency range up to 1 MHz. The temperature and the frequency dependences of ε(f T), the dielectric constant, were observed and are discussed for all the samples.

Production of high purity rare earth mixture from iron-rich spent fluid catalytic cracking (FCC) catalyst using acid leaching and two-step solvent extraction process

Le-Phuc Nguyen,Yen Thi Hai Pham,Phuong Thuy Ngo,Tri Van Tran,Loc Vinh Tran,Nam Thi Hoai Le,Luong Huu Nguyen,Tung Thanh Dang,Duc Anh Nguyen,Marco Wenzel,David Hartmann,Karsten Gloe,Jan J. Weigand,Klaus 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.5

Acid leaching and a two-step solvent extraction procedure were developed to produce high purity mixture of La and Ce from iron-rich spent FCC catalyst discharged from Dzung Quat refinery (Vietnam). Acid leaching of the spent catalyst with 2M HNO3 and a solid-to-liquid ratio of 1/3 at 80 oC in 1 h dissolved almost 90% of La while 12% of Al and 25% of Fe were transferred to the leachate. The extraction of RE metals and main impurities such as Al and Fe by a mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and tributyl phosphate (TBP) was investigated. Experiments showed that it was necessary to remove Fe before extracting RE and the optimum extraction conditions for a high recovery of RE while 0% of Al extraction were pH1, contact time=10min, and D2EHPA/TBP volume ratio= 4 : 1. At these conditions, the extraction yields of La(III) and Ce(III) were 72% and 89%, respectively. A two-step solvent extraction was developed to achieve a high purity of RE mixture, which included (1) the removal of impurity Fe by 25% (v/v) diisooctyl phosphinic acid (DiOPA) in n-octane for 140 min, (2) the extraction of rare earths by a mixture of di-2-ethylhexyl phosphoric acid (D2EHPA) and tributyl phosphate (TBP) in n-octane for 10 min without the need for adjusting the pH of the leaching solution.

Switching and Electrical Memory Effect in the Colossal Permittivity Material La2NiO4+δ

Le Van Hong,Tran Dang Thanh,Dao Nguyen Hoai Nam,,Nguyen Xuan Phuc 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

La2NiO4+δ ceramic samples were manufactured by using a solid state reaction method. The crystalline structural, magnetic and dielectric properties of the material were recorded and analyzed. A dielectric resonance, which is thought to be associated with the multiferroic behavior of the material, was observed at frequencies below 1 MHz. The I/V characteristics were easured on a capacitor-like structure, which exhibited resistance and capacitance switching when opposite voltage pulses of about 2.5 volts with a duration time of 500 ms were applied. The maximum ratios of the changes in the resistance and the capacitance were estimated to be of about 50 % and 35 % at room temperature, respectively. The electrical switching was reversible, with resistive states remaining for a rather long time. The observed capacitance switching and memory effects provide evidence for the presence of charge transfer and accumulation in the material.

AI-based Pavement Distress Evaluation and Network-Level Pavement Management Considering Homogenized Sections

Thai Son Tran,Hyun Jong Lee,Hyunwood Kim,Kideok Kim,Van Phuc Tran,Son Dong Nguyen,Junsik Lee,Jeonghun Song 한국도로학회 2022 한국도로학회 학술대회 발표논문 초록집 Vol.2022 No.10

AI-Based Pavement Distress Evaluation and Network-Level Pavement Management Considering Homogenized Sections

Thai Son Tran,Hyun Jong Lee,Hyunwood Kim,Kideok Kim,Van Phuc Tran,Son Dong Nguyen,Junsik Lee,Jeonghun Song 한국도로학회 2022 한국도로학회 학술대회 발표논문 초록집 Vol.2022 No.10

중온 재활용 아스팔트 혼합물의 실내 공용성 평가

이왕수,Do Thanh Chung,Tran Van Phuc,오영조,이현종 한국도로학회 2017 한국도로학회 학술대회 발표논문 초록집 Vol.2017 No.10

온실가스 배출 등으로 인한 지구 온난화, 이상기후 현상 등이 발생함에 따라 온실가스를 줄이기 위한 운동이 범세계적으로 확산되었다. 이 운동에 일조하기 위해 우리나라에서는 ‘저탄소 녹생성장 기본법’, ‘건설폐기물의 재활용촉진에 관한 법률’을 시행하였고, 우리나라 전체 온실가스 배출량의 16%를 차지하고 있는 도로분야에서는 지속 가능한 친환경 도로포장 기술의 개발이 진행되고 있다. 또한, 국토교통부는 “순환골재 및 순환골재 재활용제품의 의무사용에 관한 고시”를 개정 예정이며, 그 내용은 다음과 같다. 도로포장 공사구간이 1km 이상 또는 포장 면적이 9,000m2 이상인 신설 또는 확장공사의 도로, 단지, 주차장 등에 순환골재를 40%이상 의무사용 해야 하며, 향후 순환골재 의무사용 대상이 기존의 신설·확장공사뿐만 아니라 유지·관리공사를 포함하는 방향으로 확대될 예정이다. 아스팔트 콘크리트 분야에서 온실가스 배출 저감을 위한 방법으로는 순환골재 사용과 중온 아스팔트 혼합물 사용 등이 있다. 중온 아스팔트 혼합물은 가열 일반 아스팔트 혼합물 대비 생산 및 시공온도를 약 30℃ 이상 낮춰 탄소저감 효과를 볼 수 있는 혼합물을 말하며, 이 때 사용하는 첨가제를 중온 첨가제라 한다. 또한, 재생 첨가제란 재활용 아스팔트 혼합물 생산시 폐아스팔트 바인더의 물리·화학적 성질을 신규 아스팔트 바인더와 유사하게 회복시킬 수 있는 기능을 가진 첨가제를 말한다. 본 연구에서는 가열 일반 아스팔트 혼합물과 중온 일반 및 중온 재활용 아스팔트 혼합물의 실내 시험 결과를 비교하였다. 중온 일반 및 중온 재활용 아스팔트 혼합물의 실내 공용성 평가를 위해 다짐도, 동탄성계수, 피로 시험, 휠 트레킹, 수분저항성, 동적수침 시험을 수행하였다. 가열 아스팔트 혼합물 간 공용성 비교·평가시에는 동일한 공극률의 시편을 제작하여 시험을 실시하지만, 중온 혼합물의 경우에는 가열 아스팔트 혼합물과 비교해 다짐특성이 다르기 때문에 동일한 공극률에서 공용성을 비교하기에는 무리가 따른다. 다짐도, 동탄성계수, 피로 시험의 경우 현장에서 동일한 다짐 에너지를 적용한다는 가정하에 실내 시험시 선회다짐기를 사용하여 동일한 다짐 에너지로 시편을 제작하였다. 표층용 중온 재활용 혼합물의 공극률이 4%가 되게 하는 선회다짐 횟수를 기준으로 삼는 경우 중온 일반 혼합물의 공극률이 너무 작아 실내 시험 결과 비교에 문제가 있을 것이라고 판단되어 중온 일반 혼합물의 공극률이 4%가 되는 선회다짐 횟수(55회)를 기준으로 표층용 아스팔트 혼합물을 제작하였고, 기층용 혼합물의 경우 가열 일반 혼합물은 50회, 중온 재활용 혼합물은 44회를 적용하였다. 가열 일반 혼합물에 44회의 선회다짐을 한 시편의 경우 공극률이 너무 높아 시험을 진행할 수 없어 다짐횟수를 50회로 증가하였다.

Copper Tolerance of Novel Rhodotorula sp. Yeast Isolated from Gold Mining Ore in Gia Lai, Vietnam

Kim Cuc Thi Nguyen,Phuc Hung Truong,Cuong Tu Ho,Cong Tuan Le,Khoa Dang Tran,Tien Long Nguyen,Manh Tuan Nguyen,Phu Van Nguyen 한국균학회 2023 Mycobiology Vol.51 No.6

In this study, twenty-five yeast strains were isolated from soil samples collected in the goldmining ore in Gia Lai, Vietnam. Among them, one isolate named GL1T could highly tolerateCu2þ up to 10 mM, and the isolates could also grow in a wide range of pH (3–7), and temperature(10–40 �C). Dried biomass of GL1 was able to remove Cu2þ effectively up to 90.49%with a maximal biosorption capacity of 18.1 mg/g at pH 6, temperature 30 �C, and incubationtime 60 min. Sequence analysis of rDNA indicated this strain was closely related toRhodotorula mucilaginosa but with 1.53 and 3.46% nucleotide differences in the D1/D2domain of the 28S rRNA gene and the ITS1-5.8S rRNA gene-ITS2 region sequence, respectively. Based on phylogenetic tree analysis and the biochemical characteristics, the strainappears to be a novel Rhodotorula species, and the name Rhodotorula aurum sp. nov. is proposed. This study provides us with more information about heavy metal-tolerant yeasts andit may produce a new tool for environmental control and metal recovery operations.