Browsing by Author "Dewi, R."

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    KARAKTERISASI SIFAT OPTIK BAHAN BARIUM TITANAT (BaTiO3) DENGAN MENGUNAKAN SPEKTROSKOPI ULTRAVIOLET-VISIBLE (UV-Vis)
    (2013-07-11) Yulis, R.; Krisman; Dewi, R.
    The characterization of BaTiO3 by using the method of experiment and comparison of 1: 1 is reported. This research uses chemicals with different concentrations i.e 0.005 mole, 0.006 mole 0.007 mole, and different temperatures i.e 600oC, 700oC, 800oC. The purpose of this research is to obtain the absorbance (spectrums) of BaTiO3 with temperature and concentration variations, then the characterization is done using UV-Vis spectroscopy method. The research results shows that at concentrations 0,005 mole, 0,006 mole, 0,007 mole before annealing of each having a wavelength 282,0 nm, 284,0 nm, 273,0 nm gives absorbance at 3,999 a.u, and at concentrations 0,005 mole, 0,006 mole, 0,007 mole after annealing at a temperature of 600 C, 700 C, 800 C, having a wavelength each 281,0 nm, 284,0 nm, 279,0 nm gives absorbansi 3,1503 a.u.
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    PENERAPAN PEMBELAJARAN KOOPERATIF PENDEKATAN STRUKTURAL THINK PAIR SQUARE UNTUK MENINGKATKAN HASIL BELAJAR MATEMATIKA SISWA KELAS VIIa MTs AL-KAUTSAR PEKANBARU
    (2013-07-06) Dewi, R.
    PENERAPAN PEMBELAJARAN KOOPERATIF PENDEKATAN STRUKTURAL THINK PAIR SQUARE UNTUK MENINGKATKAN HASIL BELAJAR MATEMATIKA SISWA KELAS VIIa MTs AL-KAUTSAR PEKANBARU Ratna Dewi1, Rini Dian Anggraini2, Titi Solfitri3 RatnaDewi@ymail.com ABSTRACT The study was conducted in MTs AL-Kautsar Pekanbaru in the second semester of the school years 2011/2012. The subject of this study is VIA grade students of 32 students ranging from male students with academic ability heterogeneous. This study aims to improve the learning outcomes of students in the subject matter of mathematics wake flat rectangle of implementing Cooperative Learning Approach model Sturuktural Think Pair Square. This study is the research form of class action. The research was conducted in two cycles with four stages that traveled namely planning, implementation of action, observation and reflection. The results showed that students improved mathematical learning outcomes, namely increasing the percentage of students who achieve the KKM I cycle ie from 31.25% to 62.5%. Similarly, in cycle II, the percentage of students who achieve the KKM increased to 90.625%. In other words, application of cooperative learning model type Think Pair Square can increase yield grade students learn math VIA MTs AL-Kautsar Pekanbaru in particular on the subject matter of waking up in a four-year educational level 2011/2012.
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    PENGARUH SUHU ANNEALING TERHADAP MIKROSTRUKTUR BAHAN BARIUM TITANAT (BaTiO3) MENGGUNAKAN SCANNING ELECTRON MICROSCOPY (SEM)
    (2013-07-19) Zulpratama, D.; Krisman; Dewi, R.
    The samples material BaTiO3 with pellet shape have been made using experiment method of blending materials BaCO3 and TiO2 with the comparison of 1:1 as many as three samples. Each sample was annealed with the different temperature of 600, 700, and 800 C and then characterized using Scanning Electron Microscopy (SEM) in order to identify grain size and composition of the sample. The results of the characterization of SEM showed the physical form of microstructure BaTiO3 material that is shaped approaching dominant round with a different size and density. There are pores between grains of the particles, from measurement result EDX also obtained the composition of substances in samples. Material samples BaTiO3 which were annealed at the temperature of 600, 700, and 800 C have an average grain size of each is 94.34 nm, 108.7 nm, dan 131.58 nm respectively. It can be concluded that by increasing a high annealing temperature, BaTiO3 grain size will be larger.