Electronic Properties of Topological Materials: Optical Excitations in Moebius Conjugated Polymers

Electronic structures and optical excitations in Moebius conjugated polymers are studied theoretically. Periodic and Moebius boundary conditions are applied to the tight binding model of poly(para-phenylene), taking exciton effects into account. We discuss that oligomers with a few structural units are more effective than polymers for observations of effects of discrete wave numbers that are shifted by the change in boundary condition. Next, calculations of optical absorption spectra are reported. Certain components of optical absorption for an electric field perpendicular to the polymer axis mix with absorption spectra for an electric field parallel to the polymer axis. Therefore, the polarization dependences of an electric field of light enable us to detect whether conjugated polymers have the Moebius boundary.Comment: 10 pages, 6 figures, to be published in J. Phys. Soc. Jpn., Vol. 74 No. 2 (February, 2005), Letter sectio

Analysis of Switched Inductor Three-level DC/DC Converter

A non-isolated DC/DC converter with high transfer gain is proposed in this paper. The presented converter consists of the switched inductor and three-level converters. The DC/DC power converter is three-level boost converter to convert the output voltage of the DC source into two voltage sources. The main advantages of DC/DC converter are using low voltage semiconductors and high gain voltage. The steady-state operation of the suggested converter is analyzed. A prototype is developed and tested to verify the performance of the proposed converter. To sum up, the MATLAB simulation results and the experimental results have transparently approved high efficiency of proposed converter as well as its feasibility

A Generalized Modular Multilevel Current Source Inverter

This paper proposes a novel topology of multilevel current source inverter which is suitable to apply in low/medium voltage. The proposed topology is capable of producing desirable bidirectional output current levels. Furthermore, it can employ symmetrical DC current sources as well as asymmetrical ones which is a significant advantage. Asymmetrical mode makes it possible to generate a great number of output levels by appropriate selection of DC current source magnitude, needless to make changes in the hardware of the inverter. As a result, various methods are presented to compute the magnitude of needed DC current sources. In comparison to the conventional H-Bridge inverter (CHB), the proposed inverter has lessened the number of required DC current sources, switches as well as related gate driver circuits. The reduced number of required components has leads to cost and volume advantages. In addition, the control layout has become simpler. Reduction of power loss as a result of reduced number of on-state switches is the other merit of the proposed inverter. To evaluate the efficiency of the proposed inverter, its simulation and experimental results are extracted including results of various methods of determining DC current source magnitude

Spin states of zigzag-edged Mobius graphene nanoribbons from first principles

Mobius graphene nanoribbons have only one edge topologically. How the magnetic structures, previously associated with the two edges of zigzag-edged flat nanoribbons or cyclic nanorings, would change for their Mobius counterparts is an intriguing question. Using spin-polarized density functional theory, we shed light on this question. We examine spin states of zigzag-edged Mobius graphene nanoribbons (ZMGNRs) with different widths and lengths. We find a triplet ground state for a Mobius cyclacene, while the corresponding two-edged cyclacene has an open-shell singlet ground state. For wider ZMGNRs, the total magnetization of the ground state is found to increase with the ribbon length. For example, a quintet ground state is found for a ZMGNR. Local magnetic moments on the edge carbon atoms form domains of majority and minor spins along the edge. Spins at the domain boundaries are found to be frustrated. Our findings show that the Mobius topology (i.e., only one edge) causes ZMGNRs to favor one spin over the other, leading to a ground state with non-zero total magnetization.Comment: 17 pages, 4 figure

ADAPTASI MASYARAKAT BANTARAN SUNGAI TERHADAP BENCANA BANJIR DI KELURAHAN KOMO LUAR KOTA MANADO

Indonesia memiliki karakteristik geografis dan geologis yang sangat rentan terhadap perubahan iklim. Hal tersebut karena Indonesia merupakan Negara Kepulauan dengan daerah pantai yang luas dan sebagian besar populasi penduduk bertempat tinggal dikawasan pesisir pantai maupun daerah bantaran sungai. Kota Manado sebagai Ibu Kota Provinsi Sulawesi Utara dengan karakteristik wilayah yang dataran tinggi dan dataran rendah yang rentan terhadap bencana seperti banjir dan lain-lain. BPPD Kota Manado mencatat bencana terbesar di Kota Manado yang pernah tercatat sejak 169 tahun adalah banjir dan tanah longsor pada tanggal 15 Januari 2014. Tujuan Penelitian ini untuk mengetahui penyebab banjir yang di hadapi masyarakat, mengkaji adaptasi masyarakat bantaran sungai terhadap bencana banjir berdasarkan karakteristik sosial-ekonomi dan prilaku masyarakat , dan mengkaji adaptasi masyarakat di Kelurahan Komo Luar Kota Manado. Desain penelitian yang digunakan dalam penelitian ini adalah deskriptif kuantitatif menggunakanmetode survey dengan rancangan study kasus. Populasi dalam penelitian ini adalah 184 KK di Kelurahan Komo Luar Kota Manado yang terkena dampak dengan kriteria tinggi banjir tertinggi 3-4 meter, dan sampel dalam penelitian ini 64 responden dengan menggunakan metode purosive sampling di Kelurahan Komo Luar Kota Manado. Hasil penelitian ditemukan strategi adaptasi yang dilakukan masyarakat adalah menentukan rute eveakuasi sendiri yakni rumah mereka dan masjid, sampai saat ini alat evakuasi masih sederhana yang tersedia di masing-masing rumah warga, petugas pertolongan pertama tidak ada hingga kini petugas pertolongan pertama adalah masyarakat itu sendiri dengan saling membantu dalam pengurangan dampak dari resiko bencana bajir.Kesimpulan :Banjir di Kelurahan Komo Luar di sebabkan oleh faktor alam dan prilaku masyarakat, responden, strategi adaptasi yang dilakukan masyarakat dalam hal ini cukup baik dalam meminimalkan dampak resiko bencana banjir.Kata kunci :Adaptasi, Masyarakat Bantaran Sungai, dan Bencana Banji

Ensemble evaluation of hydrological model hypotheses

It is demonstrated for the first time how model parameter, structural and data uncertainties can be accounted for explicitly and simultaneously within the Generalized Likelihood Uncertainty Estimation (GLUE) methodology. As an example application, 72 variants of a single soil moisture accounting store are tested as simplified hypotheses of runoff generation at six experimental grassland field-scale lysimeters through model rejection and a novel diagnostic scheme. The fields, designed as replicates, exhibit different hydrological behaviors which yield different model performances. For fields with low initial discharge levels at the beginning of events, the conceptual stores considered reach their limit of applicability. Conversely, one of the fields yielding more discharge than the others, but having larger data gaps, allows for greater flexibility in the choice of model structures. As a model learning exercise, the study points to a “leaking” of the fields not evident from previous field experiments. It is discussed how understanding observational uncertainties and incorporating these into model diagnostics can help appreciate the scale of model structural error

SMRT Sequencing of Paramecium Bursaria Chlorella Virus-1 Reveals Diverse Methylation Stability in Adenines Targeted by Restriction Modification Systems

Chloroviruses (family Phycodnaviridae) infect eukaryotic, freshwater, unicellular green algae. A unique feature of these viruses is an abundance of DNA methyltransferases, with isolates dedicating up to 4.5% of their protein coding potential to these genes. This diversity highlights just one of the long-standing values of the chlorovirus model system; where group-wide epigenomic characterization might begin to elucidate the function(s) of DNA methylation in large dsDNA viruses. We characterized DNA modifications in the prototype chlorovirus, PBCV-1, using single-molecule real time (SMRT) sequencing (aka PacBio). Results were compared to total available sites predicted in silico based on DNA sequence alone. SMRT-software detected N6-methyl-adenine (m6A) at GATC and CATG recognition sites, motifs previously shown to be targeted by PBCV-1 DNA methyltransferases M.CviAI and M. CviAII, respectively. At the same time, PacBio analyses indicated that 10.9% of the PBCV-1 genome had large interpulse duration ratio (ipdRatio) values, the primary metric for DNA modification identification. These events represent 20.6x more sites than can be accounted for by all available adenines in GATC and CATG motifs, suggesting base or backbone modifications other than methylation might be present. To define methylation stability, we cross-compared methylation status of each GATC and CATG sequence in three biological replicates and found ∼81% of sites were stably methylated, while ∼2% consistently lack methylation. The remaining 17% of sites were stochastically methylated. When methylation status was analyzed for both strands of each target, we show that palindromes existed in completely non-methylated states, fully-methylated states, or hemi-methylated states, though GATC sites more often lack methylation than CATG sequences. Given that both sequences are targeted by not just methyltransferases, but by restriction endonucleases that are together encoded by PBCV-1 as virus-originating restriction modification (RM) systems, there is strong selective pressure to modify all target sites. The finding that most instances of non-methylation are associated with hemi-methylation is congruent with observations that hemi-methylated palindromes are resistant to cleavage by restriction endonucleases. However, sites where hemi-methylation is conserved might represent a unique regulatory function for PBCV-1. This study serves as a baseline for future investigation into the epigenomics of chloroviruses and their giant virus relatives

6,12,18,24-Tetra­meth­oxy-4,10,16,22-tetra­kis­[(meth­oxy­carbon­yl)meth­oxy]-2,8,14,20-tetra­kis­(2-phenyl­eth­yl)resorcin[4]arene

The title compound, C76H80O16, is a macrocyclic structure. This novel resorcin[4]arene derivative has (meth­oxy­carbon­yl)meth­oxy ‘head’ groups on the upper rim. The compound has a C 2v ‘boat’ geometry and there are a range of C—H⋯O contacts in the crystal structure