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Abstrak :
Penelitian ini menggunakan metode Ambient Noise Tomography (ANT) untuk menggambarkan model kecepatan grup gelombang Rayleigh pada bagian kerak atas Pulau Jawa yang memiliki kondisi tektonik yang kompleks. Data penelitian yang digunakan merupakan data waveform komponen vertikal dari 99 jaringan sensor seismik stasioner BMKG yang tersebar di Pulau Jawa pada tahun 2021. Pengolahan data waveform dilakukan mulai dari single data preparation, cross correlation dan stacking, analisis cross correlogram, pengukuran kurva dispersi, tomografi kecepatan dan yang terakhir adalah interpretasi hasil penelitian. Hasil inversi menghasilkan citra tomografi kecepatan grup gelombang Rayleigh pada kerak atas di wilayah Pulau Jawa berkisar antara 1,88 km/s hingga 2,60 km/s dan umumnya meningkat dengan bertambahnya periode pengukuran di wilayah Pulau Jawa. Penelitian ini berhasil mengidentifikasi patahan – patahan dan zona gunung api di Pulau Jawa dengan jelas yang berada pada wilayah batas kontras zona anomali kecepatan rendah dan zona anomali kecepatan tinggi. ......This study uses the Ambient Noise Tomography (ANT) method to describe the velocity model of the Rayleigh wave group in the upper crust of Java Island which has complex tectonic conditions. The research data used is vertical component waveform data from 99 BMKG stationary seismic sensor networks distributed on Java Island in 2021. Waveform data processing is carried out starting from single data preparation, cross correlation and stacking, cross correlogram analysis, dispersion curve measurements, velocity tomography and the last is the interpretation of the research results. The inversion results produce a tomographic image of the Rayleigh wave group velocity in the upper crust in the Java Island region ranging from 1.88 km/s to 2.60 km/s and generally increases with increasing measurement period in the Java Island region. This research has succeeded in clearly identifying faults and volcanic zones in Java Island which are located in the contrasting boundary of the low velocity anomaly zone and the high velocity anomaly zone.

Abstrak :
Kami melakukan perhitungan konduktivitas optis pada layered (perovskite) Pr0.5Ca1.5MnO4 untuk mengidentifikasi fenomena charge-ordering. Pemodelan melibatkan orbital Mn dan O yang berada pada bidang MnO2 dari layered Pr0.5Ca1.5MnO4. Interaksi yang diperhitungkan dalam pemodelan yaitu interaksi Coulomb inter-orbital dan intra-orbital, distorsi Jahn-Teller dan exchange interaction dengan menerapkan beberapa asumsi. Perhitungan dilakukan menggunakan Dynamical Mean Field Theory untuk mencapai self-consistency. Hasil perhitungan menunjukkan profile yang mendekati hasil eksperimen dengan puncak charge-ordering berada di bawah 1 eV dan puncak charge-transfer pada 3-3.7 eV. Di bawah temperatur TCO/OO (~325 K), puncak charge-ordering mengalami blue shift seiring dengan penurunan temperatur.

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We calculate the optical conductivity of layered (perovskite) Pr0.5Ca1.5MnO4 to capture charge-ordering phenomena. The calculations are based on a model which considers Mn and O orbitals within the MnO2 plane of layered Pr0.5Ca1.5MnO4. Interaction terms included in the model with some assumptions are the inter-orbital and intra-orbital Coulomb repulsions, the static Jahn-Teller distortion and the exchange interaction. We calculate within Dynamical Mean Field Theory to achieve self-consistency. The result shows a profile similar to recent experimental data, where the charge-ordering peak appears below 1 eV and charge-transfer peak at 3-3.7 eV. For temperature lower than TCO/OO (~325 K), the charge-ordering peak undergoes a blue shift as the temperature is decreased.

Abstrak :
This book discusses the problem of electromagnetic wave excitation in spatial regions with spherical boundaries and the accurate mathematical modeling based on numerical and analytical methods to significantly reduce the time required for developing new antenna devices. It particularly focuses on elements and systems on mobile objects of complex shape that are made of new technological materials. The experimental development of such devices and systems is an extremely time-consuming, lengthy, and expensive process. The book is intended for senior and postgraduate students and researchers working in the fields of radiophysics, radio engineering and antenna design. The authors assume that readers understand the basics of vector and tensor analysis, as well as the general theory of electrodynamics. The original results presented can be directly used in the development of spherical antennas and antenna systems for the mobile objects.

Abstrak :
This book offers engineering students an introduction to the theory of partial differential equations and then guiding them through the modern problems in this subject. Divided into two parts, in the first part readers already well-acquainted with problems from the theory of differential and integral equations gain insights into the classical notions and problems, including differential operators, characteristic surfaces, Levi functions, Green’s function, and Green’s formulas. Readers are also instructed in the extended potential theory in its three forms: the volume potential, the surface single-layer potential and the surface double-layer potential. Furthermore, the book presents the main initial boundary value problems associated with elliptic, parabolic and hyperbolic equations. The second part of the book, which is addressed first and foremost to those who are already acquainted with the notions and the results from the first part, introduces readers to modern aspects of the theory of partial differential equations.

Abstrak :
Pendekatan Hamiltonian tight binding digunakan untuk mempelajari sifat transport muatan di molekul DNA. Sifat transport muatan ini dipelajari dengan menggunakan dua model DNA yaitu model DNA Aperiodik dan model DNA G4. Model DNA Aperiodik terdiri dari 32 pasangan basa ATGC yang tersusun secara acak dengan sequence GCTAGTACGTGACGTAGCTAGGATATGCCTGA. Pada model ini dilakukan perhitungan menggunakan metode transfer matriks dan metode hamburan untuk mendapatkan probabilitas transmisi serta menghitung karakteristik I-V berdasarkan formula Landauer Büttiker dengan memvariasikan nilai kopling 𝛼 interstrand. Peningkatan nilai kopling 𝛼 interstrand memberikan dampak yang sangat baik terhadap transport muatan yaitu terjadinya peningkatan probabilitas transmisi dan karakteristik IV pada tegangan tinggi. Sedangkan, model DNA G4 terdiri dari 4 basa guanine yang tersusun membentuk struktur planar, g-quartet yang disusun secara bertumpuk. Pada model DNA ini dilakukan perhitungan panjang lokalisasi menggunakan metode transfer matriks dan perhitungan density of state (DOS) dan karakteristik I-V menggunakan pendekatan fungsi green di bawah pengaruh temperatur dan medan magnet. Temperatur menyebabkan terjadinya fluktuasi termal yang menurunkan panjang lokalisasi, density of state (DOS) dan karakteristik I-V di molekul DNA G4. Sedangkan, medan magnet menyebabkan terjadinya pergeseran fase keadaan elektron di jalur transport yang mempengaruhi panjang lokalisasi dan DOS yang berimbas pada peningkatan arus hingga di tegangan tinggi. ...... The tight binding Hamiltonian approach is used in studying charge transport properties DNA molecules. The charge transport properties are studied by using two DNA models, the Aperiodic DNA molecule and the G4 DNA molecule. The Aperiodic DNA model consist of 32 base pairs that ATGC arranged randomly with sequence GCTAGTACGTGACGT-AGCTAGGATATGCCTGA. In this model, transfer matrix method and scattering method are used in obtain transmission probability and calculating the I-V characteristic for various values of interstrand coupling α. The increase of α gives a very good impact on charge transport that is the increase of transmission probability and I-V characteristic at high voltages. G4 DNA model consists of planar structure of four guanine bases, g-quartet, which are stacked on top each other. In this DNA model, localization length is calculated using transfer matrix method and the density of state (DOS) as well as I-V characteristic are calculated using green function approach under the influence of temperature and magnetic field. The temperature causes thermal fluctuations that decreases the localization length, density of state (DOS) and I-V characteristics in G4 DNA molecule. Meanwhile, magnetic field causes a shift in electron wave phase along its travel path which is affecting the localization length and DOS which lead to current increament up to high voltage.