Dynamics of weakly coupled random antiferromagnetic quantum spin chains

We study the low-energy collective excitations and dynamical response functions of weakly coupled random antiferromagnetic spin-1/2 chains. The interchain coupling leads to Neel order at low temperatures. We use the real-space renormalization group technique to tackle the intrachain couplings and treat the interchain couplings within the Random Phase Approximation (RPA). We show that the system supports collective spin wave excitations, and calculate the spin wave velocity and spectra weight within RPA. Comparisons will be made with inelastic neutron scattering experiments quasi-one-dimensional disordered spin systems such as doped CuGeO$_3$Comment: 4 page

Quantum Phase Transition from a Spin-liquid State to a Spin-glass State in the Quasi-1D Spin-1 System Sr1-xCaxNi2V2O8

We report a quantum phase transition from a spin-liquid state to a spin-glass state in the quasi-one dimensional (1D) spin-1 system Sr1-xCaxNi2V2O8, induced by a small amount of Ca-substitution at Sr site. The ground state of the parent compound (x = 0) is found to be a spin-liquid type with a finite energy gap of 26.6 K between singlet ground state and triplet excited state. Both dc-magnetization and ac-susceptibility studies on the highest Ca-substituted compound (x = 0.05) indicate a spin-glass type magnetic ground state. With increasing Ca-concentration, the spin-glass ordering temperature increases from 4.5 K (for the x = 0.015 compound) to 6.25 K (for the x = 0.05 compound). The observed results are discussed in the light of the earlier experimental reports and the theoretical predictions for a quasi-1D spin-1 system.Comment: 26 pages, 8 figures, 3 table

On representations of Clifford algebras of ternary cubic forms

In this article, we provide an overview of a one-to-one correspondence between representations of the generalized Clifford algebra $C_f$ of a ternary cubic form $f$ and certain vector bundles (called Ulrich bundles) on a cubic surface $X$. We study general properties of Ulrich bundles, and using a recent classification of Casanellas and Hartshorne, deduce the existence of irreducible representations of $C_f$ of every possible dimension.Comment: 9 pages, to appear in proceedings for the conference "New Trends in Noncommutative Algebra: A Conference in Honor of Ken Goodearl's 65th Birthday

Strategi Kepengawasan Tumpang Sari Menuju PAUD Berkualitas

Pendidikan Anak Usia Dini (PAUD) merupakan pendidikan yang paling fundamental karena perkembangan anak di masa selanjutnya akan sangat ditentukan oleh berbagai stimulasi bermakna yang diberikan sejak usia dini. Awal kehidupan anak merupakan masa yang paling tepat dalam memberikan dorongan atau upaya pengembangan agar anak dapat berkembang secara optimal. Undang-undang Nomor 20 Tahun 2003 mengamanatkan bahwa pendidikan harus dipersiapkan secara terencana dan bersifat holistik sebagai dasar anak memasuki pendidikan lebih lanjut. Masa usia dini adalah masa emas perkembangan anak dimana semua aspek perkembangan dapat dengan mudah distimulasi. Masa emas ini hanya berlangsung satu kali sepanjang rentang kehidupan manusia. Oleh karena itu, pada masa usia dini perlu dilakukan upaya pengembangan menyeluruh yang melibatkan aspek pengasuhan, kesehatan, pendidikan, dan perlindungan

Sales Application on Yayasan Bina Insan Mulia Development Using Java Netbeans 6.0.1 and Mysql

This study contains a simple application program on the computerized sales at Bina InsanFoundation Honor. The system works is by using the input data items that are available and thesales process, which will then automatically stored in a database and display the output resultswill come out that will be received by the buyer as invoices and view reports required by thefoundation. The process of inputting and sales of computerized this makes data processing moreefficient and accurate and can provide information on existing inventory. The need forinformation is very important, especially in the business world. The author hopes to were madeabout Applications Sales at Bina Insan Foundation Honor the information about the sale can bedone better

Sintesis dan Pengukuran Konduktivitas Listrik Konduktor Superionik Gelas (Agi)x(ag2o-b2o3)1-x

SINTESIS DAN PENGUKURAN KONDUKTIVITAS LISTRIK KONDUKTOR SUPERIONIK GELAS (AgI)x(Ag2O-B2O3)1-x. Telah disintesis konduktor superionik berbasis gelas (AgI)x(Ag2O-B2O3)1-x dengan x bervariasi yaitu 0,3, 0,4, 0,5, 0,6, 0,7 dan 0,8 menggunakan teknik quenching dengan pendingin nitrogen cair. Sifat termal (AgI)x(Ag2O-B2O3)1-x yang terbentuk diamati dengan menggunakan Differential Thermal Analysis (DTA), sedangkan fasa kristal dan amorf diamati dengan teknik difraksi sinar-x (XRD). Konduktivitas ionik dari (AgI)x(Ag2O-B2O3)1-x diamati dengan cara mengukur hambatan listrik menggunakan metode-ac yang menerapkan prinsip jembatan wheatstone pada suhu yang bervariasi. Hasil yang diperoleh menunjukkan bahwa suhu transisi gelas, suhu kristalisasi dan suhu lebur (AgI)x(Ag2O-B2O3)1-x menurun dengan bertambahnya kandungan AgI. Hasil pengukuran sifat termal dan XRD tidak menunjukkan adanya transisi fasa β AgI menjadi fasa α AgI pada bahan (AgI)x(Ag2O-B2O3)1-x. Konduktivitas ioniknya ≈ 10-4 S/cm pada suhu kamar atau sekitar seribu kali lebih tinggi dibandingkan AgI murni. Konduktivitas juga bertambah dengan naiknya suhu. Bahan (AgI)0,5Ag2O-B2O3)0,5 memiliki konduktivitas paling tinggi dibandingkan konduktivitas (AgI)x(Ag2O-B2O3)1-x pada komposisi lain