9 research outputs found
La2CuO4中の量子的電子状態に関するμSRとDFTによる研究
No full textThe muon spin relaxation ( SR) method is a powerful tool to investigate the electronic state of Cu-based high-TC superconducting oxides. To reveal muon positions inside La2CuO4 gives us a useful information to achieve deeper understandings of the electronic states on its magnetically ordered state. However, any unified method to investigate muon positions have not yet been firmly established. For this reason, the SR results achieved on La2CuO4 in the early stage of high-TC history have not yet been fully explained. We are approaching this issue by using the density functional theory calculation method, with a supercell framework and including one muon as a dilute-charged impurity. The on-sites Coulomb potential, , is included to achieve correct electronic states of the La2CuO4. By considering the quantum local effects caused by the implanted muon and the Cu-spin states in the La2CuO4, we finally succeeded to reveal the muon positions that corresponds well with the SR experimental results. Adjusting the DFT and SR results, we also optimized to be 4.87(4) eV precisely, providing an accurate information of the electronic states in LCO and proposing a novel way to utilize SR experiment on many strongly correlated systems
μSR and DFT Investigations Quantum Electronic States of La2CuO4
No full textThe muon spin relaxation (SR) method is a powerful tool to investigate the electronic state of Cu-based high-TC superconducting oxides. To reveal muon positions inside La2CuO4 gives us a useful information to achieve deeper understandings of the electronic states on its magnetically ordered state. However, any unified method to investigate muon positions have not yet been firmly established. For this reason, the SR results achieved on La2CuO4 in the early stage of high-TC history have not yet been fully explained. We are approaching this issue by using the density functional theory calculation method, with a supercell framework and including one muon as a dilute-charged impurity. The on-sites Coulomb potential, , is included to achieve correct electronic states of the La2CuO4. By considering the quantum local effects caused by the implanted muon and the Cu-spin states in the La2CuO4, we finally succeeded to reveal the muon positions that corresponds well with the SR experimental results. Adjusting the DFT and SR results, we also optimized to be 4.87(4) eV precisely, providing an accurate information of the electronic states in LCO and proposing a novel way to utilize SR experiment on many strongly correlated systems.(主査) 客員教授 渡邊 功雄, 教授 網塚 浩, 教授 河本 充司理学院（物性物理学専攻
μSR and DFT Investigations Quantum Electronic States of La2CuO4 [an abstract of dissertation and a summary of dissertation review]
No full textTheoretical approach on characterizing structural and mechanical properties of industrial alloys
No full textWith the goal of entering Indonesia’s golden dream 2045 in mineral technology and utilizations, expansive researches covering both experimental and theoretical aspects are urgently required. Here, we provide theoretical study on structural and mechanical properties of various nickel-based alloys based on first-principles, density functional theory (DFT) technique. First, we evaluate the accuracy of several exchange-correlation functionals (LDA-PZ, GGA-PBE, GGA-PBEsol) by comparing the calculated lattice constants for each system with the known experimental results. Based on the best functional, we analyze structural changes caused by the mixture of different atom to the principal element of nickel. Finally, we derived the related mechanical properties for all systems based on the calculated elastic constants. Furthermore, the elastic constants can also be used to predict the stability of alloy structure
Ring Artifact on SPECT Image due to Arbitrary Position of PMT Malfunction
No full textTo obtain high-quality images using SPECT (Single Photon Computed Emission Tomography) imaging, quality control (QC) is required. QC is periodically conducted on SPECT based on standard protocol. Ring artifact are one of the factors in determining optimal image quality. Uniformity is a parameter that determines the ring artifact on SPECT image, which can be appeared as full-ring or half-ring. Those artifacts were generated since one or more PMT (photomultiplier tubes) were malfunctioning. A copper sheet with size of 2 × 2 cm2 and 1 mm thick, attached to LEHR (Low Energy High Resolution) collimator in coordinates (x,y) depending on COR (Center of Rotation) of the gamma camera, was used to generate ring artifact during image acquisition using radioisotope 9
A Critical Review of Carbonization Hydrothermal and Pyrolysis for Adsorbent Production and the Application in Industrial Dye Removal
No full textBiochar is increasingly recognised as a low-cost and efficient adsorbent for removing organic dyes from wastewater. This review outlines recent developments in biochar production, particularly comparing biochars produced via pyrolysis and hydrothermal carbonisation (HTC). While pyrolysis biochar often exhibits a higher surface area, HTC biochar offers improved oxygen-containing functional groups, contributing to enhanced dye affinity. Studies indicate that biochar can achieve adsorption capacities ranging from 2 to 1353.09 mg/g for dyes such as methylene blue and crystal violet, comparable to or exceeding that of pyrolysis-derived biochars. The review also highlights characterisation techniques such as XRD, FTIR spectroscopy, and SEM to evaluate surface functionality, porosity, and morphology, which directly influence adsorption performance. Practical implications include the suitability of HTC biochar for low-energy, decentralised wastewater treatment systems, particularly in textile and dyeing industries. By connecting production parameters with biochar properties, this review provides insights into optimizing biochar as an adsorbent, particularly for the treatment of dye-contaminated wastewater
DAMPAK NEGATIF DARI PENGGUNAAN MEDIA SOSIAL DI YAYASAN BAITUL YATIM H. CAONG
No full textMedia sosial adalah salah satu perkembangan teknologi yang memiliki andil besar dalam memberikan kemudahan bagi manusia untuk berkomunikasi dan bersosialisasi dengan kerabat atau teman. Namun terkadang kmunikasi di jejaring sosial ini dapat menjadi momok menakutkan bagi remaja. Penyalahgunaan media sosial yang menjadikan hal tersebut bumerang dalam kehiduoan anak anak di Yayasan Baitul amal H.caong. Kegiatan pengabdian masyarakat ini bertujuan Untuk memberikan sosialisai Batasan apa saja yang tidak boleh dilakuakn di media soisal. Hasil dari sosialisasi ini adalah penambahan informasi tentang hal hal yang tidak diperbolehkan dalam menggunakn media soisal sebagai media komunikasi. Dengan harapan nakan anakn di Yayasan Baitul Amal H.caong dapat menggunakan media soisal dengan bijak
Estimation of the on-site Coulomb potential and covalent state in La_{2}CuO_{4} by muon spin rotation and density functional theory calculations
No full textThe on-site Coulomb potential, U, and the covalent state of electronic orbitals play key roles for the Cooper pair symmetry and exotic electromagnetic properties of high-T_{c} superconducting cuprates. In this paper, we demonstrate a way to determine the value of U and present the whole picture of the covalent state of Cu spins in the mother system of the La-based high-T_{c} superconducting cuprate, La_{2}CuO_{4}, by combining the muon spin rotation (μSR) and the density functional theory (DFT) calculation. We reveal local deformations of the CuO_{6} octahedron followed by changes in Cu-spin distributions caused by the injected muon. Adjusting the DFT and μSR results, U and the minimum charge-transfer energy between the upper Hubbard band and the O 2p band were optimized to be 4.87(4) and 1.24(1) eV, respectively
