http://sj.hpu2.edu.vn/index.php/journal/issue/feed HPU2 Journal of Science: Natural Sciences and Technology 2024-04-26T10:14:10+07:00 HPU2 Journal of Science: Natural Sciences and Technology tapchikhoahoc@hpu2.edu.vn Open Journal Systems <p>Tạp chí Khoa học Trường ĐHSP Hà Nội 2: Chuyên san Khoa học Tự nhiên và Công nghệ</p> <p>Đơn vị quản lý: Phòng Khoa học Công nghệ và Hợp tác Quốc tế, Trường ĐHSP Hà Nội 2, số 32 đường Nguyễn Văn Linh, phường Xuân Hòa, thành phố Phúc Yên, tỉnh Vĩnh Phúc.</p> <p>Email: <a href="mailto:tapchikhoahoc@hpu2.edu.vn">tapchikhoahoc@hpu2.edu.vn</a></p> http://sj.hpu2.edu.vn/index.php/journal/article/view/207 Algebraic dependences of meromorphic mappings sharing few moving hyperplanes with truncated multiplicity 2024-01-31T08:31:30+07:00 Huong-Giang Ha gianghh@epu.edu.vn <p>In this article, we will prove an algebraic dependence theorem for meromorphic mappings into a complex projective space sharing few moving hyperplanes with different truncated multiplicity. Moreover, we also consider the weaker condition: \[\nu _{(f,{a_i}), \le k_i}\le \nu _{(g,{a_i}), \le k_i} \text{ instead of } \nu _{(f,{a_i}), \le k_i}= \nu_{(g,{a_i}), \le k_i}\] for some moving hyperplanes among the given moving hyperplanes. In order to implement this, besides using the technique reported by S. D. Quang in (Two meromorphic mappings having the same inverse images of some moving hyperplanes with truncated multiplicity, <em>Rocky Mountain J. Math</em>., vol. 52, no. 1, pp. 263–273, 2022) we have to separate the 2n + 2 moving hyperplanes from the given p+1 moving hyperplanes. After that, we count multiples of the intersection of the inverse images of the mappings f and g sharing these moving hyperplanes. Our result is an improvement of many previous results in this topic.</p> 2024-04-26T00:00:00+07:00 Copyright (c) 2024 Huong-Giang Ha http://sj.hpu2.edu.vn/index.php/journal/article/view/211 A method for growing and differentiating the C2C12 muscle cell line in the laboratory 2023-12-14T11:15:08+07:00 Ngoc - Hoan Le hoanln@hnue.edu.vn Dinh-Toi Chu Rina Yu <p class="HPU2JS-Abstract-text"><a name="_Hlk143177263"></a>Skeletal muscle-related studies have recently been applied in the combat of obesity and metabolic disorders. Culture skeletal muscle cells in in vitro plays an important role in being a promising model for those researches. In the present study, the C2C12 skeletal muscle cells were grown and differentiated in in vitro. The C2C12 myoblasts were grown in Dulbecco’s modified eagle’s medium (DMEM) containing 10% fetal bovine serum (FBS) for 4 – 5 days. The cells then reached confluent about 70% to 100% and the medium was shifted to DMEM plus 2% horse serum which leads the grown C2C12 cells becoming to differentiated myotubes. <em>Myogenin</em> mRNA levels were found to be significantly higher in the differentiated myotubes than those in the growing cells confirming the successful formation of the differentiated C2C12 cells. These results indicate that the C2C12 cell line is suitable for culture in in vitro to mimic a skeletal muscle microenvironment for further investigations.</p> 2024-04-26T00:00:00+07:00 Copyright (c) 2024 Ngoc - Hoan Le, Dinh-Toi Chu, Rina Yu http://sj.hpu2.edu.vn/index.php/journal/article/view/216 Time series analysis and applications in data analysis, forecasting and prediction 2023-10-30T03:56:05+07:00 Le-Hang Le lehang1102@gmail.com <p class="HPU2JS-Abstract-text" style="line-height: normal;"><a name="_Hlk143177263"></a><span style="font-size: 11.0pt; letter-spacing: -.2pt;">Time series analysis is an essential field in data analysis, particularly within forecasting and prediction domains. Researching and building time series models play a crucial role in understanding and predicting the temporal dynamics of various phenomena. In mathematics, time series data is defined as data points indexed in chronological order and have a consistent time interval between consecutive observations. This can include data such as daily stock prices, annual national income, quarterly company revenue, and more. The advantage of time series data is that it can capture the state of a variable over time. In contrast, the world is constantly changing, and phenomena rarely remain static they typically exhibit variations over time. Therefore, time series data has highly practical applications and is used in various fields, including statistics, econometrics, financial mathematics, weather forecasting, earthquake prediction, electroencephalography, control engineering, astronomy, telecommunications, and signal processing. ARIMA, which stands for Auto Regressive Integrated Moving Average, is a widely used time series forecasting method in data science. It is a popular model for analyzing and predicting time-dependent data points. ARIMA combines autoregression, differencing, and moving averages to capture different aspects of time series data. In this paper, we study ARIMA, which is a significant model for analyzing and predicting time series data.</span></p> 2024-04-26T00:00:00+07:00 Copyright (c) 2024 Le-Hang Le http://sj.hpu2.edu.vn/index.php/journal/article/view/215 Smart contract: Revolutionizing transactions in the digital age 2023-10-30T04:00:04+07:00 Thi-Nhung Nguyen ntnhung@ictu.edu.vn <p>Blockchain technology is a revolutionary concept that has transformed various industries, offering decentralized and secure solutions for data management. At its core, a blockchain is a distributed and immutable ledger that records transactions across a network of computers. One of the key features of blockchain is its transparency, as each participant in the network has access to the same information. The application of blockchain technology extends across diverse sectors, with finance being the most promising and well-known application domain. Cryptocurrencies, like Bitcoin and Ethereum, rely on blockchain to facilitate secure and transparent transactions. The decentralized nature of blockchain eliminates the need for intermediaries, reducing transaction costs and increasing efficiency. Beyond finance, blockchain is making significant strides in supply chain management. The emergence of blockchain technology has paved the way for <span style="text-decoration: line-through;">a</span> transformative innovation in the realm of digital transactions: smart contracts. These self-executing contracts encoded in blockchain have garnered significant attention for their potential to revolutionize the way agreements are made, executed, and enforced. This paper explores the concept of smart contracts, delving into the underlying technology, finding applications across various industries, legal implications, and future prospects.</p> 2024-04-26T00:00:00+07:00 Copyright (c) 2024 Thi-Nhung Nguyen http://sj.hpu2.edu.vn/index.php/journal/article/view/234 The origins of size-dependent UV stabilities of CdZnTeS alloyed quantum dots 2024-02-22T17:06:58+07:00 Phuong-Nam Nguyen Thi-Phuong Nguyen Anh-Duc Vu Duy-Khanh Nguyen Duy-Tung Dao Xuan-Dung Mai xdmai@hpu2.edu.vn <p class="JOSAbstract-text">CdTe-based quantum dots (QDs) have been used as active materials in various applications, such as sensing, imaging, and light-harvesting devices where the QDs are continuously illuminated by suitable lights. Passivation of CdTe QDs with stable inorganic layers to form core/shell or core/multiple-shell structures has been demonstrated to improve the stabilities of QDs against illumination. However, information related to the UV stability of newly developed CdZnTeS alloyed QDs has not been fully explored yet. Herein, we synthesized CdZnTeS alloyed QDs of different sizes and compared their size-dependent stabilities under UV irradiation. Upon UV exposure the first excitonic peak of QDs blue-shifted, gradually and the relative Cd concentration decreased indicating that QDs were steadily dissolved. We found that the smaller QDs dissolved faster than the larger QDs. By correlating this with the change in the QDs' crystalline structure corroborated by X-ray diffraction studies, we demonstrated that the alloyed structure with a sulfide-rich surface enhances the stabilities of larger QDs. The size-dependent stabilities of alloyed QDs demonstrated here provide information for selecting the right QDs for specific applications.</p> 2024-04-26T00:00:00+07:00 Copyright (c) 2024 Phuong-Nam Nguyen, Thi-Phuong Nguyen, Anh-Duc Vu, Duy-Khanh Nguyen, Duy-Tung Dao, Xuan-Dung Mai http://sj.hpu2.edu.vn/index.php/journal/article/view/225 Exponential stabilization of the class of the switched systems with mixed time varying delays in state and control 2024-01-31T09:37:21+07:00 Hoai-Nam Hoang Thi-Hong Duong hongdt@tnus.edu.vn <p>This paper presents the problem of exponential stabilization of switched systems with mixed time-varying delays in state and control. Based on the partitioning of the stability state regions into convex cones, a constructive geometric design for switching laws is put forward. By using an improved Lyapunov–Krasovskii functional in combination with matrix knowledge, we design a state feedback controller that guarantees the closed-loop system to be exponentially stable. The obtained conditions are given in terms of linear matrix inequalities (LMIs), which can be effectively decoded in polynomial time by various computational tools such as the LMI tool in MATLAB software. A numerical example is proposed to illustrate the effectiveness of the obtained results.</p> 2024-04-26T00:00:00+07:00 Copyright (c) 2024 Hoai-Nam Hoang, Thi-Hong Duong http://sj.hpu2.edu.vn/index.php/journal/article/view/217 The one-pot synthesis of photoluminescent polycarbonate based on the pyrolysis of citrate 2024-03-04T15:16:42+07:00 Thuy-Trang Pham Thi Viet-Anh Nguyen Huy-Hoang Bui Thi-Lam Ha Mohapatra Priyaranjan Xuan-Dung Mai maixdung178@gmail.com <p>Photoluminescent composites that are air-stable and water-resistant are important for outdoor applications such as road marking paints, light-converting membranes, fluorescent paints, and security inks. Photoluminescent thermoplastics fulfill all conditions but their preparation methods which are vastly based on mixing pre-synthesized fluorescent dyes and plastic could lead to emission quenching due to dye aggregation or thermal degradation. Herein, we demonstrated a simple method to prepare photoluminescent polycarbonate by thermal extrusion polycarbonate with citric acid and urea. UV-vis absorption and photoluminescent studies indicate that fluorescent carbon materials were formed via pyrolysis of the citrate. The composites exhibit light blue emission and a broad excitation band. The results demonstrated herein offer a cost-effective method to prepare diverse photoluminescent composites for outdoor applications.</p> 2024-04-26T00:00:00+07:00 Copyright (c) 2024 Thuy-Trang Pham Thi, Viet-Anh Nguyen, Huy-Hoang Bui, Thi-Lam Ha, Mohapatra Priyaranjan, Xuan-Dung Mai http://sj.hpu2.edu.vn/index.php/journal/article/view/227 Solvability Analysis of high-order Linear Differential-Algebraic Equations with time-varying coefficients 2024-02-22T16:39:01+07:00 Ha-Phi phi.ha@hust.edu.vn <p>In this paper, we study the solvability analysis of arbitrarily high-order linear differential-algebraic equations (DAEs) with time-varying coefficients, using the algebraic-behavior approach. We propose a concept of strangeness-index and construct condensed forms for high-order linear DAEs. We also discuss other structural properties like the existence and uniqueness of a solution, consistency and smoothness requirements for an initial vector and for an inhomogeneity. Our work extends the algebraic approach for DAEs and combines this approach with the behavior approach to establish a reformulation algorithm that reveals an underlying ordinary differential equation (ODE) and all hidden constraints in the DAE. This direct treatment of the system addresses the limitations of the classical approach to transforming the system into a first-order DAE. We illustrate our theoretical results with applications in mechanical systems and electrical circuits. This comprehensive study into general high-order systems is a natural progression from the extensive study of first and second-order DAEs.</p> 2024-04-26T00:00:00+07:00 Copyright (c) 2024 Ha-Phi http://sj.hpu2.edu.vn/index.php/journal/article/view/208 Investigation of structural and electronic properties of ZnO using first principle calculations 2024-03-08T09:23:41+07:00 Quoc-Van Duong vandq@hnue.edu.vn <p>In this research, first-principle calculations have been performed to study the geometry structure and electronic properties of ZnO. All possible exchange-correlation energy functionals were used to perform geometry optimization of ZnO in order to find the efficient calculation conditions. Bandgap energy, density of states (DOS), projected DOS (PDOS); and other properties of ZnO were also calculated and discussed. The calculated band-gap value of ZnO is less than 1.0 eV, much smaller than experimental value of 3.37 eV; while the PDOS results indicate the important roles of O 2p and Zn 3d orbitals in ZnO band structures. The well-known limitation of band-gap value calculations using Density Functional Theory (DFT) was solved by applying Hubbard potential on Zn 3d and O 2p orbitals. A full investigation with Hubbard value varying from 0.5 to 10 eV has been performed and the selected value is 8.0 eV for both Zn 3d and O 2p electrons. </p> 2024-04-26T00:00:00+07:00 Copyright (c) 2024 Quoc-Van Duong http://sj.hpu2.edu.vn/index.php/journal/article/view/221 Study on isolating, breeding, and cultivation of Xylaria nigripes (Klotzsch) Cooke 2024-03-11T08:58:29+07:00 Thi-Thuong Ngo Xuan-Phong Ong ongxuanphong@hpu2.edu.vn Dinh-Viet Nguyen Thi-Hang Doan Bich-Phuong Vu Viet-Hong La laviethong@hpu2.edu.vn <p>The <em>Xylaria nigripes</em> fungus is one of the medicinal materials that was used in traditional medicine. Extracts from the mycelium and fruiting bodies of the <em>X. nigripes </em>showed protecting cells, preventing DNA damage, and reducing the programmed death cell rate. In this study, the fruiting bodies of the <em>X. nigripes </em>were collected to isolate, propagate in the liquid medium, and then cultured to induce the fruiting body formation in the rice medium. The results showed that the <em>X. nigripes </em>was successfully isolated on PDAY (Potato Dextrose Agar Yeast Extract) medium, and the mycelium and spore of the <em>X. nigripes </em>had unique characteristics of the species. The biomass of <em>X. nigripes </em>grew well in a liquid nutrient medium containing 20g glucose, 1g MgSO<sub>4</sub>.7H<sub>2</sub>O, 2g KH<sub>2</sub>PO<sub>4</sub>, and 5g peptone, reaching the best mass after 21 to 28 days. Using an initial cultured liquid of <em>X. nigripes </em>to culture on rice medium, fruiting bodies were formed and developed after 14 days of culture. This result could potentially be applied to the production of <em>X. nigripes </em>biomass via mycelium and fruit bodies for application in medicine.</p> 2024-04-26T00:00:00+07:00 Copyright (c) 2024 Thi-Thuong Ngo, Xuan-Phong Ong , Dinh-Viet Nguyen, Thi-Hang Doan, Bich-Phuong Vu, Viet-Hong La