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Efek konsentrasi Prekursor Terhadap SIFAT FISIK Film Tipis BASRTIO3 (BST) SRUKRUR MFM DAN MFS yang Ditumbuhkan dengan SPIN COATING Darvina, Yenni
Sainstek Vol 11, No 1 (2008): Vol. XI No. 1, September 2008
Publisher : Lembaga Penelitian Universitas Negeri Padang

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Abstract

An BST precursor was synthesized by mixing Barium acetate 99,9%, Strontium acetate 99,99% , Titanium isopropoxide 99,999% in 2-methoxyethanol 99,9% and acetic acid glasia 100% at 120oC along 3 hours. The BST precursor concentration were 0.1 M and 0.5 M.  By employing CSD method, the BST precursor was spin coated on p-type Si (100) substrate at 3000 rpm for 30 seconds and pyrolyzed at 130oC at 10 minutes to obtain BST thin films. The BST thin films were annealed for 15 hours at 1000oC. The BST thin films structure were MFM and MFS, characterized their physical properties. It was found that grain size and thickness for the MFM structure at the BST 0,1 M were < 0.3μm and 0.6 μm., And  the BST 0.5 M were 0.5–1.0 μm and 0.9 μm. Grain size and thickness for the MFM structure at the BST 0.1 M were < 0.3μm and 0.6 μm, for BST 0.5M were 0.5–1μm and 0.8 μm .Latis constant 3.936 Ǻ. Composition of BST thin films was  same as BST precursor. Key words : Ferroelektrik, BST, Spin Coating.
EFEK GIANT MAGNETORESISTANCE PADA MULTILAYER (NiCoFe/Cu) YANG DITUMBUHKAN DENGAN METODE DC-UBMS Darvina, Yenni; Ramli, Ramli; Nora, Sri Lidia Lestari; Jamal, Mitra
EKSAKTA Vol 2 (2012)
Publisher : FMIPA UNP

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Abstract

In this paper, we present results  of  a study on (NiCoFe/Cu) multilayer grown by DC unbalanced magnetron sputtering (DC-UMBS) method onto Si (100) substrate. The aim of this study was to determine the effect of the number of layers in (NiCoFe/Cu) multilayer on the magnetoresistance ratio (MR). For ferromagnetic materials used Ni60Co30Fe10 whereas non magnetic material is Cu. Multilayer structure has been prepared consisting of 2, 3 and 4 layer. One layer consists of NiCoFe/Cu/NiCoFe thin films. The growth parameters for both NiCoFe and Cu layer are: temperature of 100 0C, growth pressure of 5.2 x10-1 torr, flow rate of Ar gas of 100 sccm, time of growth of 5 minutes, applied voltage of 600 V, and plasma currents of 0.36 A. After measurement of the MR ratio with the number of layer 2, 3 and 4 layers, the MR ratios are: 11.65%, 35.60% and 45.27%, respectively. From these results it can be concluded that as number of layers increases, the MR ratio of (NiCoFe/Cu) multilayer increases. Keyword: DC-UBMS, GMR, multilayer, NiCoFe, MR ratio
IMPLEMENTASI BUKU AJAR FISIKA BERMUATAN NILAI-NILAI KARAKTER PADA KELAS XI SEMESTER 1 DI SMA KOTA PADANG Darvina, Yenni; Masril, Masril; Murtiani, Murtiani
SEMIRATA 2015 Prosiding Bidang Fisika
Publisher : SEMIRATA 2015

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Abstract

Implementasi pendidikan karakter di sekolah dilaksanakan secara terintegrasi melalui proses pembelajaran. Agar pelaksanaannya lebih optimal, harus ditunjang oleh perangkat pembelajaran bermuatan nilai-nilai karakter.  Namun kenyataannya di sekolah perangkat pembelajaran yang ada belum optimal, terutama dalam bentuk buku ajar yang bermuatan nilai-nilai karakter. Oleh sebab itu perlu adanya buku ajar bermuatan nilai-nilai karakter yang valid, praktis dan efektif untuk digunakan. Untuk menghasilkan buku ajar yang berkualitas  maka  dilakukan penelitian Pengembangan model 4-D dengan tahapan pendefinisian (define), perancangan (design), pengembangan (development), dan penyebaran (dessiminate). Sebelum dilaksanakan tahap akhir berupa penyebaran, terlebih dahulu dilakukan uji validitas oleh validator. Setelah diperoleh Buku ajar yang valid selanjutnya dilakukan uji terbatas terhadap produk Buku ajar bermuatan nilai-nilai karakter yang dibuat, sehingga diperoleh efektifitas dan praktikalitasnya. Uji terbatas dilakukan dengan statistik one group pretest-postest design. Untuk mengetahui  efektifitasnya digunakan tes Hasil Belajar yang diberikan 2 kali yaitu sebelum uji terbatas (pretest) dan setelah uji terbatas (Postest). Praktikalitas buku ajar diperoleh dari angket yang disebarkan pada guru yang terpilih sebagai sampel. Dari penelitian yang telah dilakukan diperoleh rata-rata nilai praktikalitas 86,1 (kategori sangat baik) dan rata-rata nilai efektifitasnya 61,74 % (kategori berpengaruh kuat). Katakunci: nilai karakter, bahan ajar, penelitian pengembangan
Rancangan Laboratorum Virtual untuk Pembelajaran Fisika SMA Masril, Masril; Hidayati, Hidayati; Darvina, Yenni
JURNAL EKSAKTA PENDIDIKAN (JEP) Vol 2 No 1 (2018): JEP : Jurnal Eksakta Pendidikan
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

One of the problems found in the implementation of the curriculum of 2013 is not all competency skills can be performed well. Therefore, to overcome these problems, virtual laboratory designed to competencies skill  of physics. One of the design objectives virtual laboratory is to improve the quality of education and learning in physics in high school. The method used in this study is a research method development four D model with the definition phase , design phase , development phase, and dissemination phase.  Research has reached the stage of development and has been tested valid specialist. The instrument used in the research is a questionnaire consisting of: 1) the material substance; 2) The display of visual communication; 3) instructional design; 4) the use of software;  and 5) Linguistic. The results obtained to test the validity in general has been very good category (85.6), so that the design of virtual labs designed can already be used in high school.  
PENERAPAN DISCOVERY LEARNING BERBANTUAN VIRTUAL LABORATORY UNTUK MENINGKATKAN KOMPETENSI FISIKA SISWA SMA Masril, Masril; Hidayati, Hidayati; Darvina, Yenni
Jurnal Penelitian Pendidikan IPA Vol 5, No 1 (2019): January
Publisher : Universitas Mataram

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Abstract

The purpose of this study is to determine the effect of implementation virtual labs  through discovery learning in senior high school. The population of the study was students of  SMAN 12 Padang and the sample was two classes with cluster random sampling technique. Students were divided into two groups: experimental and control group. The research instrument used for competency of attitude is observation sheet, for competence of knowledge is multiple choice and for skill competence using working assessment. Based on the results of the research, it can be concluded that for the three competencies shows the results that the experimental class is better than the control class.
STRUKTUR MIKRO DAN SIFAT MAGNETIK DARI LAPISAN TIPIS NANOKOMPOSIT Fe3O4/PVDF Ramli, Ramli; Yulfriska, Nidya; Darvina, Yenni; Yulkifli, Yulkifli; Sanjaya, Edi; Hartono, Ambran
Spektra: Jurnal Fisika dan Aplikasinya Vol 3 No 3 (2018): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 3 Issue 3, December 2018
Publisher : Program Studi Fisika Universitas Negeri Jakarta

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Abstract

Artikel ini berhubungan dengan laporan pembuatan lapisan tipis nanokomposit Fe3O4/PVDF (Poly Vinylidine Fluoride) dengan fraksi berat nanopartikel Fe3O4 yang berbeda. Nanokomposit Fe3O4/PVDF disiapkan menggunakan metode sol-gel dan kemudian ditumbuhkan menggunakan alat spin coating di atas substrat kaca. Lapisan tipis nanokomposit Fe3O4/PVDF dikarakterisasi menggunakan XRD, FTIR, SEM, dan VSM untuk menentukan struktur mikro dan sifat magnetiknya. Fraksi berat nanopartikel Fe3O4 dalam matriks PVDF berpengaruh pada struktur mikro dan sifat magnetik nanokomposit. Hasil karakterisasi XRD dan FTIR menunjukkan bahwa nanokomposit telah terbentuk dan telah terjadi interaksi antara pengisi (Fe3O4) dengan molekul polimer PVDF. Morfologi permukaan nanokomposit memperlihatkan bentuk sperulus (spherulites) dan lamela radial. Analisis kurva histeresis dari nanokomposit Fe3O4/PVDF menunjukkan magnetisasi saturasi dari lapisan nanokomposit Fe3O4/PVDF bertambah dengan bertambahnya konsentrasi Fe3O4 dalam sampel. Pengaruh fraksi Fe3O4 dalam sampel nanokomposit Fe3O4/PVDF terhadap sifat struktur mikro dan sifat magnetik sampel dilaporkan secara rinci dalam artikel ini.
Efektivitas Lembar Kerja Siswa Virtual Laboratory pada Materi Gerak Lengkung di Kelas X SMAN Hidayati, Hidayati; Masril, Masril; Darvina, Yenni; Zakiya, Zara
JURNAL EKSAKTA PENDIDIKAN (JEP) Vol 3 No 1 (2019): JEP : Jurnal Eksakta Pendidikan
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

The purpose of this study was to determine the effectiveness of virtual laboratory worksheets on parabolic motion material and circular motion in class X of SMAN 5 Padang. To achieve the research objectives, quasi   experiments were used and one group of pretest-posttest was research design. The population is students of class X MIPA at SMAN 5 Padang who are registered in the 2018/2019 Academic Year. Simple random sampling technique is used for sampling and obtained by class X MIPA 1 as a sample. The research data includes data on attitudes, knowledge and skills competencies. Attitude competency data is obtained through attitude assessment observation sheets, then described and analyzed in graphical form. Knowledge competency data was obtained through pretest and posttest. Skills competency data are obtained through performance assessment sheets. Knowledge and skills competency data were analyzed using correlated t-test. Based on data analysis, it can be concluded that virtual laboratory worksheets on parabolic motion material and circular motion are effectively used in learning which can be seen from increasing student learning competencies in aspects of knowledge and skills after using virtual laboratory worksheets. As well as attitudinal competence shows students have done a very good attitude during learning, marked by an increase in the average value of student attitudes at each  meeting