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8th Asian Physics Symposium, APS 2019

作者： Muttaqien, F. Namari, N.A.P. Wella, S.A. Wungu, T.D.K. Suprijadi Master Program in Computational Science Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesha 10 Bandung40132 Indonesia Instrumentation and Computation Research Group Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesha 10 Bandung40132 Indonesia Nuclear Physics and Biophysics Research Group Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesha 10 Bandung40132 Indonesia Research Center for Nanosciences and Nanotechnology Institut Teknologi Bandung Jalan Ganesha 10 Bandung40132 Indonesia

We perform density functional theory (DFT) study of CO 2 adsorption on graphene supported Ni catalyst. We implement ordinary PBE functional as well as van der Waals density functional (vdW-DF) to accommodate weakly interaction between CO 2 and graphene. Based on vdW-DF calculations, we obtained that CO 2 is physisorbed on pristine graphene, in contradiction with PBE results. The adsorption energy further increases when we introduce single Ni adatom and small Ni cluster on graphene. The adsorbed CO 2 bond angle and bond length on graphene with single Ni adatom and cluster are deformed from its gas phase condition, indicating that CO 2 is chemically adsorbed on the decorated graphene area. Our results provide useful insight into appropriate design of graphene supported metal catalysts. © Published under licence by IOP Publishing Ltd.

关键词： Graphene

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Influence of Contactopy on Two-Dimensional Brazil-Nut Effect

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IOP Conference Series: Earth and Environmental science 2016年第1期31卷

作者： Teja Kesuma Dimas Praja Purwa Aji Sparisoma Viridi Suprijadi Master Program in Computational Science Institut Teknologi Bandung Indonesia Department of Physics Institut Teknologi Bandung Indonesia

Using hard sphere collision scheme and molecular dynamics method simulation, two-dimension Brazil-Nut Effect (BNE) is conducted. BNE inital configurations are artificially created to obtain number of contacts between the grains, called as contactopy. It is observed that from initial condition until the end of BNE observation, center-of-mass in vertical direction tends to decrease, while contactopy tends to increase, which are similar to the reported results in a Gedankenexperiment (Viridi et al., 2014). Initial configurations which are also dependent on contactopy influence the rise time since it can override influence of density ratio that should affect rise time (Möbius et al., 2001). We investigate on how the intruder rise time influenced by contactopy, as well as density.

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Ab Initio Study on Electronic Structure of Some Imidazole Derivatives and Its Correlation with Corrosion Inhibition Properties

Ab Initio Study on Electronic Structure of Some Imidazole De...

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International Conference on Computation in science and Engineering, ICCSE 2017

作者： Sundari, C.D.D. Setiadji, S. Nuryadin, B.W. Syafia, R. Huda, A.F. Ivansyah, A.L. Department of Chemistry Education UIN Sunan Gunung Djati Bandung Jl. A.H. Nasution No.105 Bandung West Java40614 Indonesia Department of Chemistry Faculty of Science and Technology UIN Sunan Gunung Djati Bandung Jl. A.H. Nasution No.105 Bandung West Java40614 Indonesia Department of Physics Faculty of Science and Technology UIN Sunan Gunung Djati Bandung Jl. A.H. Nasution No.105 Bandung West Java40614 Indonesia Department of Mathematics Faculty of Science and Technology UIN Sunan Gunung Djati Bandung Jl. A.H. Nasution No.105 Bandung West Java40614 Indonesia Master Program in Computational Science Faculty of Mathematics and Natural Science Institut Teknologi Bandung Jl. Ganesha No. 10 West-Java Bandung40132 Indonesia

Imidazole and some of its derivatives have been known as a good candidate for corrosion inhibition application. In this study, ab initio calculation was carried out for several imidazole derivatives i.e. 2-phenylimidazole[1,2-α]pyridine, 6-methyl-2-phenylimidazole[1,2-α]pyridine, 6-methyl-2-(4-metoxyplenylimidazole)[1,2-α]pyridine, and 6-methyl-2-(4-chlorophenylimidazole)[1,2α]pyridine, in order to investigate their electronic properties as well as its correlation with their corrosion inhibition properties. Calculations were performed using Firefly software package with RHF method and 6-31G(d,p) basis set. Based on calculation results and analysis, it was found that 6-methyl-2-(4-metoxyphenylimidazole) [1,2α]pyridine compound has better potential as corrosion inhibitor than the rest of the compounds due to its small HOMO-LUMO energy gap, low ionization potential, low electron affinity, low electronegativity, and low global hardness i.e. 10.184 eV, 7.199 eV, -2.985 eV, 2.107 eV and 5.092 eV respectively. This compound also has the highest global softness (0.098 eV), while the greatest value of the dipole moment was owned by 6-methyl-2-(4-chlorophenylimidazole)[1,2α]pyridine with value of 6.125 Debye due to the existence of Cl atom that has larger polarity than the other substituents. © Published under licence by IOP Publishing Ltd.

关键词： Pyridine

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computational Study of Inclusion Complexes between Omeprazole Enantiomer with Hydroxypropyl-β-Cyclodextrin

Computational Study of Inclusion Complexes between Omeprazol...

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International Conference on Computation in science and Engineering, ICCSE 2017

作者： Setiadji, S. Sundari, C.D.D. Nuryadin, B.W. Zayyinunnisya, H. Cahyandari, R. Ivansyah, A.L. Department of Chemistry Faculty of Science and Technology UIN Sunan Gunung Djati Bandung Jl. A.H. Nasution No.105 Bandung West Java40614 Indonesia Department of Chemistry Education UIN Sunan Gunung Djati Bandung Jl. A.H. Nasution No.105 Bandung West Java40614 Indonesia Department of Physics Faculty of Science and Technology UIN Sunan Gunung Djati Bandung Jl. A.H. Nasution No.105 Bandung West Java40614 Indonesia Department of Mathematics Faculty of Science and Technology UIN Sunan Gunung Djati Bandung Jl. A.H. Nasution No.105 Bandung West Java40614 Indonesia Master Program in Computational Science Faculty of Mathematics and Natural Science Institut Teknologi Bandung Jl. Ganesha No. 10 West Java Bandung40132 Indonesia

computational study of inclusion complexes between R/S-omeprazole as Proton Pump Inhibitor (PPI) compound with hydroxypropyl-β-cyclodextrin in three of its dimeric structure configurations (head to head, head to tail and tail to tail) has been carried out. All calculations were performed using PM3 quantum semiempirical method. computational results showed that total binding energy (BE) of R-omeprazole complex is more exothermic than total binding energy of S-omeprazole complex. The calculated binding energy of R-omeprazole complex was -74.65 kcal/mol, while for S-omeprazole complex was -64.09 kcal/mol. This results indicate that R-omeprazole inclusion complex has higher stability compared to S-omeprazole inclusion complex. The value of ΔH, ΔS, and ΔG for R-omeprazole inclusion complex formation were -77.02 kcal/mol, -0.24 cal/mol.K and -2.62 kcal/mol respectively, while the value of ΔH, ΔS, and ΔG for S-omeprazole inclusion complex formation were -66.47 kcal/mol, -0.29 cal/mol.K and 19.29 kcal/mol respectively. These values indicate that the formation of inclusion complexes between R/S-omeprazole with hydroxypropyl-β-cyclodextrin is enthalpy driven process. © Published under licence by IOP Publishing Ltd.

关键词： Binding energy

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Efficient and scalable calculation of complex band structure using sakurai-sugiura method

arXiv

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arXiv 2017年

作者： Iwase, Shigeru Futamura, Yasunori Imakura, Akira Sakurai, Tetsuya Ono, Tomoya Department of Physics University of Tsukuba Tsukuba Ibaraki305-8571 Master’s/Doctoral Program in Life Science Innovation University of Tsukuba Department of Computer Science University of Tsukuba Tsukuba Ibaraki305-8573 Department of Computer Science University of Tsukuba Tsukuba Ibaraki305-8573 Department of Computer Science University of Tsukuba Tsukuba Ibaraki 305-8573 CREST Japan Science and Technology Agency Kawaguchi Saitama332-0012 Department of Physics University of Tsukuba Tsukuba Ibaraki 305-8571 Center for Computational Sciences University of Tsukuba Tsukuba Ibaraki305-8577

Complex band structures (CBSs) are useful to characterize the static and dynamical electronic properties of materials. Despite the intensive developments, the first-principles calculation of CBS for over several hundred atoms is still computationally demanding. We here propose an efficient and scalable computational method to calculate CBSs. The basic idea is to express the Kohn-Sham equation of the real-space grid scheme as a quadratic eigenvalue problem and compute only the solutions which are necessary to construct the CBS by Sakurai-Sugiura method. The serial performance of the proposed method shows a significant advantage in both runtime and memory usage compared to the conventional method. Furthermore, owing to the hierarchical parallelism in Sakurai-Sugiura method and the domain-decomposition technique for real-space grids, we can achieve an excellent scalability in the CBS calculation of a boron and nitrogen doped carbon nanotube consisting of more than 10,000 atoms using 2,048 nodes (139,264 cores) of Oakforest-PACS. Copyright © 2017, The Authors. All rights reserved.

关键词： Carbon nanotubes

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Surface Functional Groups Effect on the Absorption Spectrum of Carbon Dots: Initial TD-DFT Study 9

Surface Functional Groups Effect on the Absorption Spectrum ...

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9th Asian Physics Symposium 2021, APS 2021

作者： Umami, Reza Permatasari, Fitri Aulia Sundari, Citra Deliana Dewi Muttaqien, Fahdzi Iskandar, Ferry Department of Physics Faculty Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesha 10 West Java Bandung40132 Indonesia Inorganic and Physical Chemistry Division Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jl. Ganesha 10 West Java Bandung40132 Indonesia Department of Chemistry Education UIN Sunan Gunung Djati Bandung Jl. Cimincrang West Java Bandung40292 Indonesia Master Program in Computational Science Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesha 10 Bandung40132 Indonesia Research Center for Nanoscience and Nanotechnology Institut Teknologi Bandung Jalan Ganesha 10 West Java Bandung40132 Indonesia

Carbon dots (CDs) have attracted considerable interest due to their remarkable performance, low cost and ease of preparation, and wide range of potential applications. Surface engineering, including modifying the surface functional group and subsequent chemical modification, is preferable to achieve the requirement of the specific application. Oxygen and Nitrogen-based surface functional groups are two common functionalizations on CDs that are subsequently generated during the synthetic process. In this study, we elucidate the optical properties of oxygen and nitrogen-functionalized CDs using time-dependent density functional theory (TD-DFT). Both considered functional groups, the carbon-oxygen double bond (-C=O) and amino groups (-NH2), are quite favourable to tailor the optical properties of CDs, especially in enhancing its absorption spectrum. Moreover, the carbonyl (-C=O) and amino (-NH2) functional groups effectively serve a new absorption peak in the first near-infrared window (650-900 nm). Our results suggest the potential application of the amino and carbonyl functionalized CDs as a photothermal agent in photothermal cancer therapy. © Published under licence by IOP Publishing Ltd.

关键词： Optical properties

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Coefficient of restitution dependence of intruder rise time in two-dimensional Brazil-nut effect

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AIP Conference Proceedings 2016年第1期1723卷

作者： T. Kesuma D. P. Purwa Aji S. Viridi Suprijadi 1Master Program in Computational Science Institut Teknologi Bandung Bandung 40132 Indonesia 2Master Program in Computational Science Institut Teknologi Bandung Bandung 40132 Indonesia 3Department of Physics Institut Teknologi Bandung Bandung 40132 Indonesia 4Department of Physics Institut Teknologi Bandung Bandung 40132 Indonesia

Brazil-Nut Effect (BNE) is a granular material phenomenon, where larger grains (usually known as intruder) rise to the top when the granular system vibrated. We observe a single intruder rise time of BNE phenomenon in a two-dimensional molecular dynamics simulation of hard spheres collision scheme. Some experiments have shown that some granular properties, such as size and density ratio, play an important role to determine the rise time. However, other property, such as coefficients of restitution, is considered not to have a measurable impact. We explore the intruder inelasticity dependence of the rise time by varying its coefficient of restitution. We found that the intruder rise time tends to be flat for relatively high coefficient of restitution and increases exponentially below a certain deflecting point for low coefficient of restitution. This holds for specific mass ratio.

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Biogas production and its utilization in internal combustion engines - A review

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Process Safety and Environmental Protection 2024年 186卷 518-539页

作者： Vasan, Vinod Sridharan, Naveen Venkatesh Feroskhan, M. Vaithiyanathan, Sugumaran Subramanian, Balaji Tsai, Pei-Chien Lin, Yuan-Chung Lay, Chyi-How Wang, Chin-Tsan Ponnusamy, Vinoth Kumar Vellore Institute of Technology Chennai600127 India Department of Mechanical Engineering Faculty of Engineering and Technology SRM Institute of Science and Technology Kattankulathur Chennai603203 India Kaohsiung City807 Taiwan Department of Computational Biology Institute of Bioinformatics Saveetha School of Engineering Saveetha Institute of Medical and Technical Sciences Tamil Nadu Chennai602105 India Institute of Environmental Engineering National Sun Yat-sen University Kaohsiung804 Taiwan Center for Emerging Contaminants Research National Sun Yat-sen University Kaohsiung804 Taiwan Master's Program of Green Energy Science and Technology Feng Chia University Taichung City407102 Taiwan Department of Mechanical and Electro-Mechanical Engineering National I-Lan University I Lan Taiwan Research Center for Precision Environmental Medicine Kaohsiung Medical University Kaohsiung City807 Taiwan Kaohsiung City807 Taiwan Division of Operation and Maintenance Engineering Luleå University of Technology Luleå Sweden Department of Chemistry National Sun Yat-sen University Kaohsiung804 Taiwan

This review presents the significance and current challenges associated with fossil fuels, highlighting the need for cleaner and more sustainable energy sources. The significant object of the current study is to concentrate on increased interest in utilizing biogas as a viable substitute for traditional fuels, delving into its characteristics, benefits, accessibility, feasibility, and prospects as an environmentally sustainable energy option. The current study extensively analyses the prospect and significance of biogas in mitigating emissions regulations in Internal Combustion Engines (ICEs). This paper provides a comprehensive overview of recent research on incorporating biogas in internal combustion engines, focusing on emission reduction and the corresponding impact on engine performance. The subject matter encompasses a range of facets about biogas, encompassing its origins, chemical composition, purification, enhancement techniques, and requisite engine adjustments to enable the effective utilization of biogas as an alternative fuel. The study also evaluates the performance of biogas-fuelled ICEs based on the results of cross-referencing with contemporary research and investigates peripheral aspects such as additive inclusion to increase biogas capabilities as fuel and potential applications in advanced engine modes of operation. The review identifies research gaps in the domains of biogas processing and utilization in ICEs and acknowledges existing challenges specific to the adoption of biogas as a conventional fuel alternative. Future research directions are also prescribed, further highlighting the importance of transitioning from fossil fuels to meet environmental goals and global energy demands. © 2024 The Institution of Chemical Engineers

关键词： Biogas

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Reconstructing suspended sediment concentrations in the Mekong River Basin via semi-supervised-based deep neural networks

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science of the Total Environment 2024年 955卷 176758页

作者： Nguyen, Thi Thu Ha Vu, Duc Quang Doan, Ngoc Phu Chi, Huynh Thi Khanh Li, Peixin Binh, Doan Van An, Yimeng Dung, Pham Tuan Hoang, Tuan A. Son, Mai Thai Laboratory of Environmental Sciences and Climate Change Institute for Computational Science and Artificial Intelligence Van Lang University Ho Chi Minh City Viet Nam Faculty of Environment School of Technology Van Lang University Ho Chi Minh City Viet Nam Department of Computer Science and Information System Thai Nguyen University of Education Viet Nam School of Electronics Electrical Engineering and Computer Science Queen's University Belfast United Kingdom College of Economics and Management Nanjing University of Aeronautics and Astronautics China Master program in Water Technology Reuse and Management Faculty of Engineering Vietnamese-German University Binh Duong Province Ben Cat City Viet Nam

The Mekong River Basin (MRB) is crucial for the livelihoods of over 60 million people across six Southeast Asian countries. Understanding long-term sediment changes is crucial for management and contingency plans, but the sediment concentration data in the MRB are extremely sporadic, making analysis challenging. This study focuses on reconstructing long-term suspended sediment concentration (SSC) data using a novel semi-supervised machine learning (ML) model. The key idea of this approach is to exploit abundant available hydroclimate data to reduce training overfitting rather than solely relying on sediment concentration data, thus enhancing the accuracy of the employed ML models. Extensive experiments on daily hydroclimate and SSC data obtained from 1979 to 2019 at the three main stations (i.e., Chiang Saen, Nong Khai, and Mukdahan) are conducted to demonstrate the superior performance of the proposed method compared to the state-of-the-art supervised techniques (i.e., Random Forest, XGBoost, CatBoost, MLP, CNN, and LSTM), and surpasses existing semi-supervised methods (i.e., CoReg, ⊓ Model, ICT, and Mean Teacher). This approach is the first semi-supervised method to reconstruct sediment data in the field and has the potential for broader application in other river systems. © 2024 The Author(s)

关键词： Self-supervised learning

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The prediction of molecule atomization energy using neural network and extreme gradient boosting

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Journal of Physics: Conference Series 2021年第1期2072卷

作者： M Sumanto M A Martoprawiro A L Ivansyah Master Program in Computational Science Faculty of Mathematics and Natural Sciences Bandung Institute of Technology Bandung 40132 Indonesia Department of Chemistry Faculty of Mathematics and Natural Sciences Bandung Institute of Technology Bandung 40132 Indonesia Department of Computational Science Faculty of Mathematics and Natural Sciences Bandung Institute of Technology Bandung 40132 Indonesia

Machine Learning is an artificial intelligence system, where the system has the ability to learn automatically from experience without being explicitly programmed. The learning process from Machine Learning starts from observing the data and then looking at the pattern of the data. The main purpose of this process is to make computers learn automatically. In this study, we will use Machine Learning to predict molecular atomization energy. From various methods in Machine Learning, we use two methods namely Neural Network and Extreme Gradient Boosting. Both methods have several parameters that must be adjusted so that the predicted value of the atomization energy of the molecule has the lowest possible error. We are trying to find the right parameter values for both methods. For the neural network method, it is quite difficult to find the right parameter value because it takes a long time to train the model of the neural network to find out whether the model is good or bad, while for the Extreme Gradient Boosting method the time needed to train the model is shorter, so it is quite easy to find the right parameter values for the model. This study also looked at the effects of the modification on the dataset with the output transformation of normalization and standardization then removing molecules containing Br atoms and changing the entry in the Coulomb matrix to 0 if the distance between atoms in the molecule exceeds 2 angstrom.

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