Science and Technology Development Journal - Natural Sciences 2021-02-28T17:00:15+00:00 Phuc Van Pham Open Journal Systems Energy Difference Of High Frequency Electromagnetic Waves Amplitude In Detecting Buried Objects At Ho Chi Minh City, Vietnam 2021-02-28T17:00:15+00:00 Thuan Van Nguyen Cuong Van Anh Le <p>Ground penetrating radar method (GPR) is common place in imaging buried objects, such as: supply water and drainage systems, electric and telecom cables. For shallow geology, GPR method has provided high-resolution sections containing subsurface information. In processing data, the velocity of GPR wave is the most important parameter. It helps to exactly specify the structure of a geology sections. Defining a wrong velocity may lead to an erroneous result. In this research, we are going to present two processing steps to define the electromagnetic wave velocity and the position of object from GPR data that was acquired by using a shield antenna machine prototype. The first step is application of Kirchhoff migration and energy difference graphs to calculate the electromagnetic wave velocity. In the second step, the result of migrated sections consisting of hyperbole diffraction was evaluated. If migrated using the right velocity, the diffracted hyperbola will focus on its peak and have the maximum energy. Finally, we used the workflow to define the velocity, the position and the size of the object from real GPR data collected at Go Vap district, Ho Chi Minh City, Vietnam.</p> 2021-01-23T00:00:00+00:00 ##submission.copyrightStatement## Study on adenosine loading capacity of porous nanosilica for application in drug delivery 2021-02-28T17:00:14+00:00 Dat Ngoc Xuan Mai Lua Thi Xuan Danh Huy Dinh Minh Dang Ha Van Nguyen Hanh Thi Kieu Ta Tan Le Hoang Doan Tri Minh Le Thang Bach Phan <p>Mesoporous silica nanoparticles (MSNs) are used as drug delivery materials because of their outstanding features such as large surface area, easy synthesis and high biocompability. In this study, inorganic mesoporous nanosilica material, MCM-41, was synthesized by sol-gel hydrothermal method using tetraethyl orthosilicate precursor (TEOS). The material structure and composition were analyzed by X-ray power diffraction (P-XRD), N2 adsorption isotherm, thermalgravimetric analysis (TGA) and Fourier-transform infrared spectroscopy (FT-IR). Its morphology was examined by scanning electron microscopy (SEM) and transmission electron microscope (TEM). The results showed that synthesized MCM-41 has a spherical shape, homogeneous with an average size of 100 nm. The specific surface area is 845 m2 g􀀀1, the pore size is approximately 35 Å. It has high thermal stability until 800oC. FT-IR result showed the formation of the Si-O-Si bond in the structure. The adenosine loading capacity of MCM-41 was investigated based on the influence of loading factors including adenosine concentration, time, solvent, and temperature. The kinetics and thermodynamics of the adsorption processes were also studied. The adenosine loading ability on MCM-41 is significant high, approximately 1699 mg g􀀀1. The kinetic and thermodynamic results showed that the drug adsorbed of MCM-41 occurred with fast rate and spontaneously. Moreover, the release profile of adenosine proved that the drug release process occurred quickly which is suitable for application in acute disease treatment.</p> 2021-01-23T00:00:00+00:00 ##submission.copyrightStatement## Synthesis of heterogeneous catalysts based on manganese oxides applied for the aerobic oxidation of p-hydroxybenzyl alcohol to p-hydroxybenzaldehyde 2021-02-28T17:00:13+00:00 Lam Anh Le Viet Thi Xuan Thi Luu Tien Khoa Khoa Le <p>In order to synthesize p-hydroxybenzaldehyde from p-hydroxybenzyl alcohol under oxygen atmosphere, we prepared the new heterogeneous catalysts based on manganese oxides by in-situ growth method at different pH values. The crystal structure, phase composition, morphology, and surface groups of catalysts were characterized by powder X-ray diffraction, field emission electron scanning microscopy and Fourier transform infrared spectroscopy. According to the experimental results, the solution pH used for the preparation of the catalysts strongly affected their properties and their catalytic activities. When the pH was increased from 2 to 4, the a-Mn2O3 content increased with the dominant presence of the rod-like particles. The quantity of Mn on the surface also enhanced which might improve the conversion of p-hydroxybenzyl alcohol while maintaining the high selectivity to p-hydroxybenzaldehyde (about 70%). However, when the pH was highr than 4, the quantity of rod-like particles,a-Mn2O3 and surface Mn species decreased which lowered the catalytic activity.</p> 2021-01-23T00:00:00+00:00 ##submission.copyrightStatement## Synthesis of five propargylamines derivative via the multicomponent reaction catalyzed by a deep eutectic solvent 2021-02-28T17:00:11+00:00 Hàng Thị Anh Hưng Lý Đức Phát Phuong Hoang Tran <p>Deep eutectic solvents (DES), a new generation ionic liquids, are green reactive media in organic synthesis, electrochemical, and biomass conversion. In this paper, we have developed a deep eutectic solvent [ethylene glycol]4[ZnCl2], simply prepared from choline chloride with ethylene glycol and used as a catalyst for the three-component reaction to synthesize propargylamine from available substrates including piperidine, phenylacetylene and benzaldehyde derivatives. The reaction mixture was activated by magnetic stirring and the optimization of conditions was investigated including temperature, time, catalytic mass, substrate effect and recycled catalyst. At 80 ◦ C, we successfully synthesized 5 propargylamine derivatives over a period of 180 minutes with high efficiency and only used 2% moles of catalyst. Desired products are structurally identified by NMR and MS (nuclear magnetic resonance 1H, 13C NMR and gas chromatography coupled mass spectrometry GC-MS). The results showed that DES [ethylene glycol]4[ZnCl2] catalyzed the efficiency of this reaction and the ability to reuse many times with negligible reduction in activity. Research to expand the scope of the substrate (heterocyclic oxygen and nitrogen compounds) and reaction mechanism are underway in the laboratory. Simple, efficient reaction processes have been the potential for industrial applications.</p> 2021-01-25T00:00:00+00:00 ##submission.copyrightStatement## Researching trends of rainfall change in Ninh Thuan in the context of climate change by the non-parametric method 2021-02-28T17:00:10+00:00 Tuan Hoang Nguyen Truong Thanh Canh <p>The purpose of this study is to analyze the trend of precipitation change in Ninh Thuan province in the context of Climate Change. In this study, the authors used precipitation data at rain gauges with a minimum duration of 24 years and a maximum of 36 years. The main method was used in this study is the non-parametric method, namely Mann-Kendall analysis and the Theil-Sen slope. The research was conducted under the support of ProULC 5.1 and MAKESEN 1.0 software. The results showed that annual rainfall in Ninh Thuan province tended to increase in the time series of observation. Specifically, the downward trend of rainfall was mainly in March and increased from July to November. Along with that, through the index regarding the trend of increase and decrease of rainfall, the study also showed a prediction of the trend of increasing rainfall for the area. Forecast results of 2035 rainfall in Ninh Thuan the highest the increase is expected 7.7% and in 2050 is 13.8%. The study results have reflected the actual situation of rainfall change in the context of climate change with the stations having statistical significance (p &lt;0.05). The research results are the basis for Ninh Thuan province to develop solutions to adapt and mitigate climate change in the fields of Socio-Economic life.</p> 2021-01-26T00:00:00+00:00 ##submission.copyrightStatement## Analysis of the selenium (Se) content in the toenail of colorectal cancer patients 2021-02-28T17:00:09+00:00 Phuong Truc Huynh Trần Tuấn Anh Nguyễn Văn Hạnh Nguyễn Thị Trúc Linh Trương Thị Hồng Loan Hồ Mạnh Dũng Nguyễn Văn Đông Đinh Thanh Bình <p>Selenium (Se) is a trace element that plays an important role in the biological functions of the human body. Toenails are considered as suitable materials for finding the relationship between trace element content with human diseases. The goal of this study is to analyze and evaluate the Se content in the toenails of colorectal cancer patients in order to find out the risk of cancer in human. The Se content in the toenails of 60 colorectal cancer patients (63.3% for men) and 22 healthy persons (54.5% for men) was analyzed by the k0-standardization method of the instrumental neutron activation analysis technique. The results of the analysis showed that Se contents ib healthy persons were 1.13 mg/g and 1.32 mg/g for men and women, respectively; for colon cancer patients were 0.70 mg/g and 0.84 mg/g for men and women, respectively; for rectal cancer patients 0.86 mg/g and 0.82 mg/g for men and women, respectively. By the statistical analysis, it showed that the Se content was significantly different between the patients and the normal patients (p&lt;0.05), but there was no significant difference between women and men. The conclusion of this study was that the Se content in the toenails of colorectal cancer patients is lower than that of normal patients.</p> 2021-01-27T00:00:00+00:00 ##submission.copyrightStatement## Antioxidant, anti-bacterial activity of Perilla frutescens ethanol extract and induction of hairy roots by Agrobacterium rhizogenes 2021-02-28T17:00:08+00:00 TRA DONG PHUONG LE THI MONG VUONG QUACH NGO DIEM PHUONG <p><em>Perilla frutescens</em>, a plant of the Lamiaceae, is commonly used for traditional medicine to treat diseases (cold, headache, cough, tympanites, poisoning, ...) because it contains many secondary compounds with bioactivities. Roots, stems and leaves of <em>P. frutescens</em> have been extracted with ethanol. These extracts have also been investigated antioxidant by DPPH method and antibacterial by agar-well-diffusion method. The results showed that these extracts possess antioxidant and antibacterial activity. By specific reactions, we found that phenols, flavonoids, saponins, alkaloids and glycosides were contained in all extracts of <em>P. frutescens</em>, but triterpenoids were only found in leaf extract. These secondary compounds are involved in the antioxidant and antibacterial activity of <em>P. frutescens</em>. Next, hairy roots of <em>P. frutescens</em> were induced by <em>Agrobacterium rhizogenes</em> ATCC 15834. The results suggested that leaves were the highest-efficiency (67.67 ± 3.51 % of samples produced hairy roots). 20 minutes of immersion and 72 hours of co-culture are optimal for induction of hairy roots. These results are a pre-requisition for further studies related to hairy root cultures aimed production of bioactive compounds.</p> 2021-01-28T00:00:00+00:00 ##submission.copyrightStatement## Effect of Eu3+ doping concentration on the structural and luminescence properties of NaYF4: Eu3+ nanoparticles 2021-02-28T17:00:07+00:00 Cao Thi My Dung Tran Thi Thanh Van Lê Thuy Thanh Giang <p>In our study, hexagonal-NaYF4: Eu3+ nanoparticles were synthesized by the solvothermal method at 180◦C for 24 hours. The typical vibrational spectrum showed the appearance of characteristic organic modes of oleic acid in the sample. The presence of elements such as Na, Y, F and Eu was indicated in the energy-dispersive X-ray spectroscopy (EDX). X-ray diffraction (XRD) patterns revealed that the NaYF4 host possessed the hexagonal structure when the doping contents below 5 mol%. At the Eu3+ amount of 10 mol%, the XRD appeared additional peaks of cubic phase of NaYF4 host. Both XRD and TEM data showed that the crystal sizes increase slightly as a function of Eu3+ doping concentration. Under an excitation at 395 nm, photoluminescence (PL) spectra revealed that the ratio of emission intensity between orange and red were controlled by changing the doping concentration. The optimal doping concentration was about 7 mol% for achieving the highest emission intensity. Moreover, PL data also demonstrated that a part of ions Eu3+ could occupy at Y3+ sites in the crystal structure of NaYF4. Because of their outstanding luminescent properties, NaYF4:Eu nanoparticles would the potential material for applications in biomedical medicine, optoelectronics.</p> 2021-02-01T00:00:00+00:00 ##submission.copyrightStatement## Synthesis of ZnO material: A new approach by hydrothermal method 2021-02-28T17:00:06+00:00 Vu Huynh Tan Quyen Pham My Luan Nguyen The Trang Huynh Thi Thien <p>Zinc oxide (ZnO) material possesses various morphologies which have given ZnO many fascinating applications in practice. Thus, the controlled synthesis of morphology and size of ZnO microstructures has attracted great interest. Many synthetic methods exhibited their effectiveness in producing pure ZnO, and the hydrothermal synthesis expresses its own considerable advantages for controlling the morphology of ZnO with low particle-size distribution. Moreover, the hydrothermal synthesis can be performed under mild condition rather than the conventional harsh ceramic method. In this work, we performed hydrothermal synthesis by altering different initial seeds by pre-treating of Zinc acetate solution prior to hydrothermal action. Characterization methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman and Infrared (IR) spectroscopy were used to determine the morphology and surface functional groups of ZnO final products. Firstly, we processed the pretreatment of Zinc acetate solution by annealing it at 90 ◦C for 1h before putting the solution into autoclave together with NH3 solution for hydrothermal synthesis (this process is called as two-step hydrothermal synthesis). Secondly, the reaction temperatures (120 ◦C, 150 ◦C, 180 ◦C) were investigated to provide the role of temperature synthesis in controlling size and shape of ZnO, and at 150 ◦C, ZnO particles were formed with reasonable uniform morphology. Finally, we examined the effects of initial seeds by pre-treating Zinc acetate solution with H2O2, or, the initial seeds change from only Zn(OH)2 (without H2O2) to mutual existence of Zn(OH)2 and ZnO2 (with H2O2). In this case, ZnO Wurtzite phase was obtained with 100% purity at 180 ◦C, or at higher temperature than other samples whose ZnO Wurtzite phase was formed at only 150 ◦C. The results show that the nature of initial seeds greatly impact not only on the shape and size, but also on the surface functional groups of ZnO final product.</p> 2021-02-01T00:00:00+00:00 ##submission.copyrightStatement## The variable size consideration of hydroxyapatite extracted from bovine bone at different temperature furnaces 2021-02-28T17:00:05+00:00 Linh Vân Hà Cao Huu Tien Diem Mai thi Tran <p>Current bone regeneration surgeries focus on regenerating damaged bone tissue structures rather than replacing them. Bone-derived hydroxyapatite (HAP) is a natural bone component with good bone resilience, emerging and a promising bone graft material. Factors in the synthesis process are very important to the properties of hydroxyapatite. The purpose of this study is to assess the effect of three different furnaced temperatures on the size and phase purity of the HA crystal. The research consists of the following two stages: after combining physical and chemical methods in the first period to eliminate most of the organic components; bones continue to be heated at temperatures of 600oC, 700oC and 800oC to create the various size of HA crystals in bone particles. Product composition and size of HA crystal are determined by TGA, XRD, FTIR, SEM, EDX methods. The results show that crystal size and phase purity can be controlled and increased with the temperature. In particular, the HA crystal size did not change significantly in the range of 600◦C but increased 10-times above 700◦C. Single crystal HA is expected to form in the range of 600 - 700◦C. After the sample was heated to 600◦C, the organic compounds such as blood and bone marrow were completely burned. In addition, two trace elements, Na and Mg, were not completely removed as in other cases but were still retained inside the bone particle. The Ca/P ratio is 1.63 is similar to the Ca/P ratio found in human bones.</p> 2021-02-02T00:00:00+00:00 ##submission.copyrightStatement## Effect of selenization time on optical, electrical properties and structure of CZTSSe thin films 2021-02-28T17:00:03+00:00 Tuấn Anh Đào Kiều Loan Phan Thị Tuấn Hùng Lê Vũ Hữu Kế Nguyễn <p>In this paper, we present a fabrication process of high crystallinity CZTSSe absorber layer. The CZTS structure is firstly prepared by spin-coating method, and then the film is converted into CZTSSe via selenization process using graphite box and tube furnace. The Se powder has been loaded into graphite box and used as source of selenizing vapors. Keeping the annealing temperature as constant, the structural, optical, electrical properties, and composition of CZTSSe thin films are investigated by changing the annealing time. X-ray diffraction revealed that these thin films are high crystallinity and strong preferential orientation along the (112) direction. The Raman spectra show the presence of the kesterite CZT Se phase which confirm the linkage of Se in structure. The band gaps (E<sub>g</sub>) of the CZT Se thin films varied from 1,19 to 1.62 eV depend on the selenization times. At optimal annealing times, the p-type CZTSSe film has bandgap energy, hole concentration, and resistivity of 1,19 eV, 2,68 x 10<sup>19</sup> cm<sup>-3</sup> and 0,86Ω.cm respectively which are suitable for photovoltaic application.</p> 2021-02-03T00:00:00+00:00 ##submission.copyrightStatement## Investigate the effect of electrolyte and additives on the electrochemical performance of commercial hard carbon materials based Na-ion batteries 2021-02-28T17:00:02+00:00 Võ Thị Ngọc Giào Tuyên Thi Kim Huynh Phạm Thanh Liêm Lê Minh Kha Lê Mỹ Loan Phụng <p>Electrolytes play an important role in the battery components it determines the electrochemical window or the working potential region of the battery according to the LUMO and HOMO energy levels and reflects its thermodynamic stability when contacting with the electrode materials. The choice of the electrolyte affects significantly the specific energy, safety, cycle life, storage performance, or operating conditions of batteries. Besides, the electrolytes could be perfectly improved its performance within the addition of some essential additives, which also help to increase the performance of the battery. In this study, the effects of NaPF6, NaClO4, NaOTf, NaFSI, and NaTFSI salts on the hard carbon anode performance were investigated in the carbonate ester solvents including EC:DMC:PC (1:1:1) of 1 M salt concentration without and with additives FEC, VC, and Py13. The compatibility hard carbon electrode-electrolyte systems were investigated for their electrochemical performance by using Galvanostatic cycling with potential limitation, Cyclic voltammetry, and electrochemical impedance spectroscopy in coin-cell type. Among the studied electrolytes, the electrolyte EC:DMC:PC (1:1:1) + 1 M NaOTf exhibited the best electrochemical performance. The specific capacity was above 246 mAh/g after 100 cycles and the Coulombic efficiency higher than 99.6%.</p> 2021-02-04T00:00:00+00:00 ##submission.copyrightStatement##