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.

LKY-047: First Selective Inhibitor of Cytochrome P450 2J2

Phuc, Nguyen Minh,Wu, Zhexue,O, Yuseok,Lee, Jee-Hyun,Oh, Sangtaek,Song, Gyu-Yong,Liu, Kwang-Hyeon American Society for Pharmacology and Experimental 2017 Drug metabolism and disposition Vol.45 No.7

<P>Highly selective cytochrome P450 CYP2J2 (CYP2J2) inhibitors suitable for reaction phenotyping are currently not available. (7S)-(+)-(4-Nitro-phenyl)-acrylic acid, 8,8-dimethyl-2-oxo-6,7-dihydro2H, 8H-pyrano[ 3,2-g] chromen-7-yl-ester (LKY-047), a decursin derivative, was synthesized, and its inhibitor potencies toward CYP2J2 as well as other cytochrome P450 (P450) enzymes in human liver microsomes (HLM) were evaluated. LKY-047 was demonstrated to be a strong competitive inhibitor of CYP2J2-mediated astemizole O-demethylase and terfenadine hydroxylase activity, with K-i values of 0.96 and 2.61 mu M, respectively. It also acted as an uncompetitive inhibitor of CYP2J2-mediated ebastine hydroxylation with a K-i value of 3.61 mu M. Preincubation of LKY-047 with HLMs and NADPH did not alter inhibition potency, indicating that it is not a mechanism-based inhibitor. LKY-047 was found to be a selective CYP2J2 inhibitor with no inhibitory effect on other human P450s, such as CYPs 1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D6, 2E1, and 3A (IC50 > 50 mu M). These in vitro data support the use of LKY-047 as a selective CYP2J2 inhibitor with potential application in the identification of P450 isoforms responsible for drug metabolism in reaction phenotyping assays.</P>

The Impact of Financial Development on Economic Growth: Empirical Evidence from Transitional Economies

Phuc Tran NGUYEN,Trinh Tuyet Thi PHAM 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.11

This article examines the role of financial development in economic growth in a number of transitional economies where the financial systems were newly established or reformed only in the early 1990s to facilitate their transition from centrally planned economies to marketbased ones. Based on a dataset collected from 29 transitional economies and 5 Asian developing economies covering the period 1990–2020, an empirical endogenous growth model is specified and estimated using the generalized method of moments (GMM). Three measures of financial development are used to investigate the relative role of the banking system and stock exchange market in the process of transition and growth. The results show that the three measures of financial development are crucial determinants of economic growth in transitional economies but the link seems to be in an inverted U-shape. This suggests the existence of thresholds for different channels of the financial sector to expand to positively influence growth. When becoming too large relative to the size of the economy, the financial system would have become a factor not conducive to growth. The growth convergence hypothesis is also confirmed and the impacts of other growth determinants are overall consistent with the extant literature.

A New Approach for Development of Quadruped Robot Based on Biological Concepts

Phuc Thinh Doan,Hoang Duy Vo,김학경,김상봉 한국정밀공학회 2010 International Journal of Precision Engineering and Vol.11 No.4

This paper proposes the design and development results of a new quadruped robot. The proposed new quadruped robot has a couple of advantages of flexible locomotion. The quadruped robot is designed and modeled based on a new concept that is the structure model with three segments of quadruped legs. New leg configuration with the simplified operation of four hip actuators is introduced. The posture of the new quadruped robot is more similar to the posture of dog than that of the previous quadruped robots. The objective of this paper is to develop a quadruped robot, which can walk and run in a trot gait with a simple PID controller. Numerical simulation and experimental results are shown to prove the locomotion performance of the proposed controller for the proposed quadruped robot.

Identification of Genome-wide SNPs by Genotyping by Sequencing in a Collection of Pear cultivars

Phuc Lam Nguyen,Sung-Chur Sim 한국원예학회 2021 한국원예학회 학술발표요지 Vol.2021 No.10

Cultivated pears (Pyrus spp.) are a major fruit crop with high nutritional value in the Rosaceae family. With next-generation sequencing technologies, single nucleotide polymorphisms (SNPs) have commonly been used to evaluated genetic variations in crop species. In this study, we collected 48 pear cultivars representing Asian pears (P. pyrifolia) and performed genotyping by sequencing (GBS) to discover genome wide SNPs. The Illumina HiSeq X sequencing of GBS library generated 774.1 million raw reads with an average length of 151 bp in the collection of pear cultivars. The length of trimmed reads was 105.1 Gb indicating 208x coverage of a pear reference genome assembly (504 Mb). A total of 412,766 confident SNPs was found across 17 pear chromosomes. Of these, a subset of 478 SNPs was filtered based on ≥ 0.3 of polymorphic information content (PIC), ≤ 15% of heterozygote rate, and physical distribution on each chromosome. This subset consisted of 326 SNPs from coding sequences and 152 SNPs for non-coding sequences. To develop a molecular tool for variety identification, the 478 SNPs were used to estimate both Nei’s and Euclidean genetic distances in the 48 pear cultivars. The dendrogram based on these genetic distances demonstrated that all of pear cultivars were differentiated using the SNP markers. This result suggests that the SNP resource from this study will be useful to develop a high-throughput DNA barcoding system for variety identification in cultivated pears.

ROBUST TRAFFIC LIGHT DETECTION AND CLASSIFICATION UNDER DAY AND NIGHT CONDITIONS

Phuc Manh Nguyen,Vu Cong Nguyen,Son Ngoc Nguyen,Linh My Thi Dang,Ha Xuan Nguyen,Vinh Dinh Nguyen 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10

Recently, traffic light detection and classification systems have been studied and developed to build an autonomous car by many research institutes, universities, and companies. However, the results of existing traffic light detection systems are still not stable under day and night conditions. It is difficult to detect the location of traffic light due to their small size. Moreover, traffic lights’ shapes are also similar to advertisement lights in a city road. Therefore, this paper proposed a new approach to improve the performance of existing traffic light detection systems by using the benefits of hand-crafted features and deep learning techniques. Experimental results show that the proposed system obtained the detection rate of 80% under night conditions, while the color-based density method only got the detection rate of 50.43% under night conditions.

Fabrication and Characterization of Immiscible Fe-Cu Alloys using Electrical Explosion of Wire in Liquid

Phuc, Chu Dac,Thuyet, Nguyen Minh,Kim, Jin-Chun The Korean Powder MetallurgyMaterials Institute 2020 한국분말재료학회지 (KPMI) Vol.27 No.6

Iron and copper are practically immiscible in the equilibrium state, even though their atomic radii are similar. As non-equilibrium solid solutions, the metastable Fe-Cu alloys can be synthesized using special methods, such as rapid quenching, vapor deposition, sputtering, ion-beam mixing, and mechanical alloying. The complexity of these methods (multiple steps, low productivity, high cost, and non-eco-friendliness) is a hinderance for their industrial applications. Electrical explosion of wire (EEW) is a well-known and effective method for the synthesis of metallic and alloy nanoparticles, and fabrication using the EEW is a simple and economic process. Therefore, it can be potentially employed to circumvent this problem. In this work, we propose the synthesis of Fe-Cu nanoparticles using EEW in a suitable solution. The powder shape, size distribution, and alloying state are analyzed and discussed according to the conditions of the EEW.

Optimization of the eco-friendly synthesis of graphene oxide from graphite using Plackett–Burman and Box–Behnken models for industrial production orientation

Phuc Nguyen Thien,Giang Nguyen Thi Huong,An Vu Nguyen Thien Truong,Nam Nguyen Thanh Hoai,Anh Ly Duc,Nguyen Huynh Cam,An Hoang,Phong Mai Thanh,Hieu Nguyen Huu 한국탄소학회 2023 Carbon Letters Vol.33 No.2

In this study, graphene oxide (GO) was synthesized by the improved Hummers’ method. The degree of oxidation from graphite (Gi) to GO was determined through interlayer spacing calculated from X–ray diffraction. Besides, the effect of KMnO4:Gi ratios (X1), H2SO4 volume (X2), oxidation temperature (X3), oxidation time of stage 1 (X4), and oxidation time of stage 2 (X5) was screened by the Plackett–Burman model. The simultaneous impact of three factors that influenced the degree of oxidation (X1, X2, and X3) was studied by the Box–Behnken experimental model of response surface methodology to achieve suitable conditions for the GO synthesis process. The characterization of GO product was investigated via the modern analytical methods: X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, UV–Vis spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. In addition, the study was also carried out on a pilot scale for orientation in industrial application with the yield of 14 g/batch.

ON PETERSON'S OPEN PROBLEM AND REPRESENTATIONS OF THE GENERAL LINEAR GROUPS

Phuc, Dang Vo Korean Mathematical Society 2021 대한수학회지 Vol.58 No.3

Fix ℤ/2 is the prime field of two elements and write 𝒜₂ for the mod 2 Steenrod algebra. Denote by GL_d := GL(d, ℤ/2) the general linear group of rank d over ℤ/2 and by ${\mathfrak{P}}_d$ the polynomial algebra ℤ/2[x₁, x₂, …, x_d] as a connected unstable 𝒜₂-module on d generators of degree one. We study the Peterson "hit problem" of finding the minimal set of 𝒜₂-generators for ${\mathfrak{P}}_d$. Equivalently, we need to determine a basis for the ℤ/2-vector space $$Q{\mathfrak{P}}_d:={\mathbb{Z}}/2{\otimes}_{\mathcal{A}_2}\;{\mathfrak{P}}_d{\sim_=}{\mathfrak{P}}_d/{\mathcal{A}}^+_2{\mathfrak{P}}_d$$ in each degree n ≥ 1. Note that this space is a representation of GL_d over ℤ/2. The problem for d = 5 is not yet completely solved, and unknown in general. In this work, we give an explicit solution to the hit problem of five variables in the generic degree n = r(2^t - 1) + 2^ts with r = d = 5, s = 8 and t an arbitrary non-negative integer. An application of this study to the cases t = 0 and t = 1 shows that the Singer algebraic transfer of rank 5 is an isomorphism in the bidegrees (5, 5 + (13.2⁰ - 5)) and (5, 5 + (13.2¹ - 5)). Moreover, the result when t ≥ 2 was also discussed. Here, the Singer transfer of rank d is a ℤ/2-algebra homomorphism from GL_d-coinvariants of certain subspaces of $Q{\mathfrak{P}}_d$ to the cohomology groups of the Steenrod algebra, $Ext^{d,d+*}_{\mathcal{A}_2}$ (ℤ/2, ℤ/2). It is one of the useful tools for studying these mysterious Ext groups.

Object Detection-based Semantic Map Building for A Semantic Visual SLAM System

Phuc H. Truong,Sujeong You,Sanghoon Ji 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10

In this paper, we propose a novel semantic visual simultaneous localization and mapping (SLAM) system which can provide rich semantic information of landmarks in the map. The system is created based on a visual SLAM system using a RGBD camera. We integrate an object detection stage on the top of the SLAM system to obtain semantic landmarks of the scene. The semantic object-based landmarks are continuously saved into a semantic map to not only describe context information, but also update the semantic map in dynamical environments where objects can be moved passively. The experimental results demonstrated the validity of the proposed system.