100 research outputs found
Numerical verification of Percival's conjecture in a quantum billiard
In order to verify Percival's conjecture [J. Phys. B 6,L229 (1973)] we study
a planar billiard in its classical and quantum versions. We provide an
evaluation of the nearest-neighbor level-spacing distribution for the Cassini
oval billiard, taking into account relations with classical results. The
statistical behavior of integrable and ergodic systems has been extensively
confirmed numerically, but that is not the case for the transition between
these two extremes. Our system's classical dynamics undergoes a transition from
integrability to chaos by varying a shape parameter. This feature allows us to
investigate the spectral fluctuations, comparing numerical results with
semiclassical predictions founded on Percival's conjecture. We obtain good
agreement with those predictions, in clear contrast with similar
comparisons for other systems found in the literature. The structure of some
eigenfunctions, displayed in the quantum Poincar\'e section, provides a clear
explanation of the conjecture.Comment: 8 pages, 9 figures, to appear in Physical Review E, vol. 57, issue 5
(01 May 1998
Classical and quantum decay of one dimensional finite wells with oscillating walls
To study the time decay laws (tdl) of quasibounded hamiltonian systems we
have considered two finite potential wells with oscillating walls filled by non
interacting particles. We show that the tdl can be qualitatively different for
different movement of the oscillating wall at classical level according to the
characteristic of trapped periodic orbits. However, the quantum dynamics do not
show such differences.Comment: RevTeX, 15 pages, 14 PostScript figures, submitted to Phys. Rev.
Decay of the Sinai Well in D dimensions
We study the decay law of the Sinai Well in dimensions and relate the
behavior of the decay law to internal distributions that characterize the
dynamics of the system. We show that the long time tail of the decay is
algebraic (), irrespective of the dimension .Comment: 14 pages, Figures available under request. Revtex. Submitted to Phys.
Rev. E.,e-mail: [email protected]
THE EFFECT OF MEDIA VISUAL IN THREE DIMENSIONS TOWARDS THE RESULT OF MATH LEARNING AT ELEMENTARY SCHOOL
Penelitian ini merupakan penelitian eksperimen semu dengan desain non equivalent control group designs yang dilatarbelakangi oleh rendahnya hasil belajar matematika siswa. Penelitian ini bertujuan untuk mengetahui perbedaan hasil belajar matematika siswa antara siswa yang memperoleh pembelajaran menggunakan media visual tiga dimensi dengan siswa yang memperoleh pembelajaran dengan media dua dimensi. Penelitian ini dilaksanakan di SD Muhammadiyah 6 Pekanbaru pada semester genap tahun pelajaran 2016/2017. Subjek penelitian adalah siswa kelas IV di SD Muhammadiyah 6 Pekanbaru dengan siswa kelas IVA sebagai kelas kontrol dan kelas IVB sebagai kelas eksperimen. Tahapan awal pada penelitian ini adalah memberikan tes awal terhadap kelas kontrol dan eksperimen, selanjutnya menerapkan pembelajaran dengan menggunakan media visual tiga dimensi pada kelas eksperimen dan media visual dua dimensi pada kelas kontrol. Langkah terakhir yaitu memberikan tes akhir pada kelas kontrol dan eksperimen. Hasil penelitian menunjukkan bahwa terdapat perbedaan peningkatan hasil belajar yang signifikan dengan taraf signifikan 0,05 yang ditunjukkan dari rata-rata tes awal (pretest) kelas eksperimen 54,96 menjadi 79,13 pada tes akhir (postest) dengan rata-rata peningkatan (gain) 0,54 (termasuk kategori sedang). Sedangkan kelas kontrol memiliki peningkatan rata-rata tes awal (pretest) dari 55,67 menjadi 64,33 pada tes akhir (postest) dengan rata-rata peningkatan (gain) 0,05 (termasuk kategori rendah)
Monte Carlo simulations of interacting particle mixtures in ratchet potentials.
There are different models of devices for achieving a separation of mixtures of particles by using the ratchet effect. On the other hand, it has been proposed that one could also control the separation by means of appropriate interactions. Through Monte Carlo simulations, we show that inclusion of simple interactions leads to a decrease of the ratchet effect and therefore also a separation of the mixtures.Fil: Fendrik, Alejandro JosĂ©. Universidad Nacional de General Sarmiento. Instituto de Ciencias; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; ArgentinaFil: Romanelli, Lilia Mabel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
Pelaksanaan Pembelajaran Daring (Online) Dimasa Pandemi Covid-19 di UPT SD Negeri Pulerejo 02 Kecamatan Ngantru Kabupaten Tulungagung Tahun Pelajaran 2020/2021
Tujuan penelitian ini adalah mendiskrisikan proses pelaksanaan pembelajaran daring, mendiskripsikan problematika yang dihadapi guru , mendeskripsikan upaya mengatasi problematika yang dihadapi guru dalam pelaksanaan kelas daring (online) selama masa pandemi covid-19 pada pembelajaran tematik Kelas I s.d III. Penelitian ini dilakukan Di UPT SD Negeri Pulerejo 2 Kecamatan Ngantru. Teknik pengumpulan data yang digunakan adalah Observasi, wawancara dan dokumentasi. Hasil penelitiannya adalah sebagai berikut 1) Proses pembelajaran tematik pada siswa kelas I s.d III selama masa pandemi covid-19 pada awalnya mengalami beberapa kendala terutama pada kompetensi guru, siswa dan orang tua dalam menyiapkan pembelajaran daring. Guru harus menyesuaian metode dan media pembelajaran berupa penyesuaian perencanaan RPP, penggunaan smartphone, media tehnologi informasi , dan sumber belajar online. 2) upaya yang dilakukan adalah terus melatih ketrampulan guru, siswa dan orang tua dalam mengoperasikan google classroom, zoom dan komunikasi di wa group, cara menjawab tugas dan melakukan evaluasi tugas siswa melalui foto dan dikirim ke wa group serta cara penulisan laporan; 3) Problematika yang dialami guru adalah keterbatasan fasilitas dan pengetahuan mengenai teknologi, membuat pembelajaran daring (online) hanya dapat dilakukan melalui aplikasi whatsapp, tidak semua siswa mempunyai smartphone, mahalnya kuota internet selama masa pandemi, koneksi internet yang tidak stabil, kurangnya pendampingan orang tua pada saat pembelajaran menyebabkan siswa kurang disiplin, keluhan siswa mengenai tugas yang sangat menumpuk.
 
Transport and dynamical properties of inertial ratchets
In this paper we discuss the dynamics and transport properties of a massive
particle, in a time dependent periodic potential of the ratchet type, with a
dissipative environment. The directional currents and characteristics of the
motion are studied as the specific frictional coefficient varies, finding that
the stationary regime is strongly dependent on this parameter. The maximal
Lyapunov exponent and the current show large fluctuations and inversions,
therefore for some range of the control parameter, this inertial ratchet could
originate a mass separation device. Also an exploration of the effect of a
random force on the system is performed.Comment: PDF, 16 pages, 7 figure
Hubungan Minat Belajar dengan Hasil Belajar Matematika Siswa Kelas V Sdn Gugus 4 Kecamatan Limapuluh Kota Pekanbaru
One of several factor which influenced learning achievement is interest. This study aims to determine the relationship between student interest in student learning outcomes in mathematics fifth grade students of SDN Cluster 4 Districts Limapuluhkota Pekanbaru. Pebelitian methods are correlational. Mechanical sampling using cluster. Methods of data collection using a scale and technical documentation of the value of MID second semester. The analysis technique used is the technique of analysis Product Moment. Test requirements analysis in the form of normality and linearity test. Engineering analysis and test requirements analysis using SPSS 20. Results of research is conducted indicates that there is a relationship between interest in learning the mathematics learning outcomes fifth grade students of SDN group 4 Districts Limapuluhkota Pekanbaru obtained rxy of 0.374 with a low correlation level and also interest in learning to give effect to the results studied at 14%. Dioeroleh t test results obtained thitung 3.722 and 1.663 ttabel this case shows that there is a significant relationship between interest in learning the mathematics learning outcomes fifth grade students of SDN Cluster 4 Districts Limapuluhkota Pekanbaru
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