43 research outputs found

    Influence of Heat Treatment on the Morphologies of Copper Nanoparticles Based Films by a Spin Coating Method

    Get PDF
    We have investigated the influence of heat treatment on the morphologies of copper nanoparticles based films on glass slides by a spin coating method. The experiments show that heat treatment can modify the sizes and morphologies of copper nanoparticles based films on glass slides. We suggest that through changing the parameters of heat treatment process may be helpful to vary the scattering and absorbing intensity of copper nanoparticles when used in energy harvesting/conversion and optical devices

    Giant All-Optical Modulation of Second-Harmonic Generation Mediated by Dark Excitons.

    Get PDF
    All-optical control of nonlinear photonic processes in nanomaterials is of significant interest from a fundamental viewpoint and with regard to applications ranging from ultrafast data processing to spectroscopy and quantum technology. However, these applications rely on a high degree of control over the nonlinear response, which still remains elusive. Here, we demonstrate giant and broadband all-optical ultrafast modulation of second-harmonic generation (SHG) in monolayer transition-metal dichalcogenides mediated by the modified excitonic oscillation strength produced upon optical pumping. We reveal a dominant role of dark excitons to enhance SHG by up to a factor of ∼386 at room temperature, 2 orders of magnitude larger than the current state-of-the-art all-optical modulation results. The amplitude and sign of the observed SHG modulation can be adjusted over a broad spectral range spanning a few electronvolts with ultrafast response down to the sub-picosecond scale via different carrier dynamics. Our results not only introduce an efficient method to study intriguing exciton dynamics, but also reveal a new mechanism involving dark excitons to regulate all-optical nonlinear photonics

    PEMBELAJARAN LUKIS TOTEBAG PADA MATA PELAJARAN SENI BUDAYA DI KELAS X MIA 3 SMA NEGERI 3 BOYOLALI TAHUN AJARAN 2017/2018

    Get PDF
    ABSTRAK Muhammad Fahmi Al Amiq. PEMBELAJARAN LUKIS PADA TOTEBAG DALAM MATA PELAJARAN SENI BUDAYA DI KELAS X MIA 3 SMA NEGERI 3 BOYOLALI TAHUN AJARAN 2017/2018. Skripsi, Fakultas Keguruan dan Ilmu Pendidikan, Universitas Sebelas Maret Surakarta, Januari 2018. Tujuan penelitian ini adalah untuk mengetahui: (1) Proses pelaksanaan pembelajaran Lukis Totebag di kelas X MIA 3 SMA Negeri 3 Boyolali tahun ajaran 2017/2018. Dan (2) Bagaimana bentuk hasil karya Lukis Totebag yang dihasilkan siswa di kelas X MIA 3 SMA Negeri 3 Boyolali tahun ajaran 2017/2018. Penelitian ini menggunakan pendekatan kualitatif. Sumber data yang digunakan adalah informan yang dipilih yaitu Bapak Subandiyo S.Pd selaku guru mata pelajaran seni budaya di kelas X MIA 3 SMA Negeri 3 Boyolali, serta foto proses pembelajaran, hasil karya siswa dan dokumen arsip. Teknik yang digunakan dalam pengumpulan data adalah observasi langsung, wawancara terstruktur dan mendalam, serta dokumentasi. Uji validitas data dilakukan dengan membandingkan sumber data yang di peroleh berupa daftar hasil wawancara dengan Bapak Subandiyo S.Pd selaku guru mata pelajaran Seni Budaya dengan siswa di kelas X MIA 3 SMA Negeri 3 Boyolali, serta review informant. Analisis data yang digunakan adalah model analisis mengalir, yaitu: reduksi data, sajian data, dan penarikan kesimpulan. Hasil penelitian ini menunjukkan bahwa: (1) Pembelajaran Lukis Totebag diawali dengan pembuatan RPP, selanjutnya pembelajaran dilaksanakan selama tiga kali pertemuan. Strategi yang digunakan guru dalam pembelajaran ini adalah pendekatan scientific. Metode pembelajaran yang digunakan meliputi metode ceramah, tanya jawab, diskusi, dan pemberian tugas. Media pembelajaran yang digunakan berupa slide power point dan media visual berupa sampel karya dari guru. Evaluasi pembelajaran dilakukan dengan menilai aspek kognitif, afektif, dan psikomotorik. Proses pembuatan karya dilakukan dengan beberapa langkah, yaitu membuat sketsa, proses pewarnaan, dan finishing. (2) Secara umum pembuatan karya lukis totebag siswa sudah baik, teknik lukis pada pewarnaan dan finishing dalam membuat karya lukis totebag sudah baik. Karya lukis totebag yang dihasilkan oleh siswa sudah mengandung unsur-unsur seni rupa, yaitu: garis, bentuk, bidang, gelap terang, dan warna. Selain itu, karya lukis totebag yang dihasilkan oleh siswa juga sudah mengandung prinsip-prinsip seni rupa, yaitu: irama (rhytm), dominasi (dominance), keseimbangan (balance), kesatuan (unity), keserasian (harmony), dan kesebandingan (proportion). Kata Kunci: Seni Budaya, Pembelajaran Seni Rupa, Lukis Toteba

    An Underwater Vector Propulsion Device Based on the RS+2PRS Parallel Mechanism and Its Attitude Control Algorithm

    No full text
    In order to overcome the disadvantages of some existing autonomous underwater vehicles (AUVs), such as actuator extraposition and degree-of-freedom (DOF) redundancy, a 2-DOF vector propeller propulsion system with built-in actuator based on the deficient DOF parallel mechanism is proposed. The RS+2PRS (Revolute-Spherical+ Prismatic-Revolute-Spherical) parallel mechanism is used as the main structure, and the driving parts are placed in the interior of the AUV cabin, which is beneficial to the sealing and protection of the propulsion system. In addition, the motion parameters decoupling shows that the two independent parameters are the precession angle and the nutation angle of the propeller installation platform. Therefore, the attitude control algorithm uses two prismatic joints as driving units to establish the nonlinear mapping model with the two Euler attitude angles. In the end, the simulation analysis and the real device are used to verify the feasibility of the attitude control algorithm and the in situ adjustment function of the propeller, which lays the theoretical foundation for engineering applications in the future

    Advances on Penetrating Imaging of Building Layout Technique Using Low Frequency Radio Waves

    No full text
    Obtaining the internal layout of an unfamiliar building before entering the building has important practical significance and research value, as it can be applied for various services, such as anti-terrorism operations and disaster relief. Low-frequency electromagnetic waves can propagate through common building materials, and then the target information behind the wall is obtained safely and stably. Therefore, using low frequency radio waves to obtain the information behind the wall has become the research focus in the field of building layout reconstruction. To reveal the development context of this field and predict the possible future development trends, this paper summarizes the domestic and foreign public literature in this field since the onset of the 21st century. The results of the relevant literature indicate that the techniques of using low-frequency electromagnetic waves to reconstruct building layout currently include three types: through-the-wall radar imaging technology based on reflected wave measurement, radio-frequency tomography technology based on transmitted wave measurement, and wall position estimation technology based on multipath signals. These three technologies have achieved several practical research results. This article clarifies the development history of the main content covered by these technologies, which mainly includes the principle of through-the-wall radar imaging of stationary targets behind the wall, the observation mode of building internal structure based on through-the-wall radar, the reconstruction technology of building internal structure on the basis of through-the-wall radar imaging, the inversion technology of building internal structure on the basis of radio-frequency tomography, and the wall position estimation technology based on multipath signals. We also discuss the development trend of this field. In the past two decades, the development history of building layout penetrating imaging using low-frequency radio waves shows a change from the traditional airborne and vehicle-mounted building-layout-reconstruction platforms to new platforms such as microrobots and unmanned aerial vehicles. The corresponding reconstruction method has been developed from the traditional radar imaging technology to a variety of new methods, including image enhancement and sparse reconstruction. The results indicate that the building-layout-reconstruction technology is developing in the direction of systematization, diversification, and intelligence

    An Imaging Dictionary Based Multipath Suppression Algorithm for Through-Wall Radar Imaging

    No full text
    corecore