2,093 research outputs found

    Polaron Recombination in Pristine and Annealed Bulk Heterojunction Solar Cells

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    The major loss mechanism of photogenerated polarons was investigated in P3HT:PCBM solar cells by the photo-CELIV technique. For pristine and annealed devices, we find that the experimental data can be explained by a bimolecular recombination rate reduced by a factor of about ten (pristine) and 25 (annealed) as compared to Langevin theory. Aided by a macroscopic device model, we discuss the implications of the lowered loss rate on the characteristics of polymer:fullerene solar cells.Comment: 3 pages, 4 figure

    Unusual nanostructures of "lattice matched" InP on AlInAs

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    We show that the morphology of the initial monolayers of InP on Al0.48In0.52As grown by metalorganic vapor-phase epitaxy does not follow the expected layer-by-layer growth mode of lattice-matched systems, but instead develops a number of low-dimensional structures, e.g., quantum dots and wires. We discuss how the macroscopically strain-free heteroepitaxy might be strongly affected by local phase separation/alloying-induced strain and that the preferred aggregation of adatom species on the substrate surface and reduced wettability of InP on AlInAs surfaces might be the cause of the unusual (step) organization and morpholog

    IMPLEMENTASI PARENTING DALAM DEMOKRASI SOCIETY PROGRAM BELAJAR DARI RUMAH (BDR) SEKOLAH DASAR DRAMAGA BOGOR

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    Esensi Physical Distancing dengan mengalihkan pembelajaran tatap muka ke dalam sistem pembelajran daring yang mengharuskan semua komponen untuk melakukan Program Belajar dari Rumah (BDR). Program ini mesti dilakukan dengan Demokrasi Society, baik oleh pendidik maupun orang tua, tiada lain guna berkontribusi untuk mendidik anak lebih maksimal di rumah secara daring.Tujuan penelitian ini, yakni untuk mengetahui parenting dimensi kontribusi orang tua dalam mewujudkan demokrasi society peserta didik dalam Program BDR di masa New Normal Covid-19. Metode penelitian menggunakan pendekatan kualitatif dengan pengumpulan data melalui wawancara mendalamHasil peneitian ini menunjukan bahwa (1). Peran orang tua dalam Program Belajar Dari Rumah (BDR) yaitu sebagai pembimbing, pendidik, dan pengasuh dalam mengembangkan potensi serta bakat anak sesuai dengan instruksi pembelajaran guru kelas, akan tetapi fungsi tersebut dianggap kurang maksimal karena dipengaruhi oleh rendahnya latar belakang pendidikan, sibuk bekerja dan kurangnya perhatian menyebabkan anak tidak termotivasi belajar, tidak mengerjakan tugas harian dan lebih memilih bermain. (2). Demokrasi Sociaty peserta didik dalam aspek perhatian, keadilan, pembimbingan dan arahan belajar dianggap tidak terpenuhi, dibuktikan dengan banyak peserta didik yang tidak mau ditemani belajar oleh orang tua mereka karena dianggap galak, tidak sabar dan bahkan terjadi kekerasan. (3). Orang tua memiliki hambatan sarana dan prasarana terbatas terutama ketiadaan handphone 4G yang menyebabkan sarana belajar, seperti group whatapps, video pembelajaran dan quis berbasis foam antara guru, komite sekolah dan orang tua menjadi tidak efektif dan efisien

    The moral discourses of ‘post-crisis’ neoliberalism: a case study of Lithuania’s Labour Code reform

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    This article problematizes the neoliberal reconfiguration of labour rights in Lithuania, a newer European Union member state, in which the impacts of the global economic and financial crisis were particularly severe and where radical austerity measures were subsequently imposed. Now, after six years, in an attempt to resolve the exhaustion of previous austerity-based solutions for economic recovery, a new Labour Code is being introduced which will further weaken labour protections and labour rights. This article analyses conflicting positions in current debates over Labour Code reform. It attempts to map the mobilization of strategic discursive resources in an unfolding dialogical ‘moral’ politics of Labour Code reform in the current conjuncture of ‘post- crisis’. Theoretically, this article draws upon the seminal work of the early Soviet Marxist scholar V. N. Voloshinov in proposing a dialogical method which foregrounds the interconnections of language, class and ideology

    Conditions for entangled photon emission from (111)B site-controlled Pyramidal quantum dots

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    A study of highly symmetric site-controlled Pyramidal In0.25Ga0.75As quantum dots (QDs) is presented. It is discussed that polarization-entangled photons can be also obtained from Pyramidal QDs of different designs from the one already reported in Juska et al. (Nat. Phot. 7, 527, 2013). Moreover, some of the limitations for a higher density of entangled photon emitters are addressed. Among these issues are (1) a remaining small fine-structure splitting and (2) an effective QD charging under non-resonant excitation conditions, which strongly reduce the number of useful biexciton-exciton recombination events. A possible solution of the charging problem is investigated exploiting a dual-wavelength excitation technique, which allows a gradual QD charge tuning from strongly negative to positive and, eventually, efficient detection of entangled photons from QDs, which would be otherwise ineffective under a single-wavelength (non-resonant) excitation

    Wettability and "petal effect" of GaAs native oxides

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    We discuss unreported transitions of oxidized GaAs surfaces between (super)hydrophilic and hydrophobic states when stored in ambient conditions. Contact angles higher than 90deg and high adhesive force were observed for several air-aged epitaxial samples grown under different conditions as well as on epi-ready wafers. Regardless of the morphologies of the surface, superhydrophilicity of oxygen-plasma treated samples was observed, an effect disappearing with storage time. Reproducible hydrophobicity was likewise observed, as expected, after standard HCl surface etching. The relation between surface oxides and hydrophobic/hydrophilic behavior is discussed

    Symbolic power: the future of nuclear energy in Lithuania

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    EU accession states may have thrown off their Soviet past in political terms, but abandoning some of the Soviet era technologies is proving to be harder. Civil nuclear power is on the way out in most of Europe, but for some ex-Soviet countries this may present serious problems of economic, social and cultural transformation -- especially in countries like Lithuania, where nuclear power supplies the bulk of the electricity. The issue has come to a head given the EU's insistence that several ex-Soviet states must agree to close their nuclear plant as a condition of EU entry. Lithuania is the accession country most wedded to and certainly most reliant on nuclear power. It has a nuclear plant which uses a technology (the RBMK, Chernobyl-type reactor) which the EU has insisted should be closed rapidly on safety grounds. This has proved an unpopular requirement in Lithuania for a variety of reasons. There are problem with ensuring continued energy supplies and replacing the lost employment and earning power. However Lithuania also has a more general commitment to this technology as a symbol of national prowess and independence. During and immediately after the struggle for national independence in 1991, the country had a mass anti-nuclear movement. This has been analysed as a covert expression of nationalist and anti-Soviet feeling, given that most opposition to nuclear power evaporated after independence (Dawson 1996). Subsequently the EU ruled that Lithuania's Ignalina nuclear plant should be closed. Yet now it is widely seen as a national asset, a view reinforced by resentment about the EU apparently imposing an unwarranted closure policy. This article will analyse how public and policy views on nuclear power have changed over time in Lithuania and how its symbolic meaning has changed during different phases of transformation of the Lithuanian society
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