Hasil Pencarian

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Hasil Pencarian

Ditemukan 4344 dokumen yang sesuai dengan query
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Ubbelohde, Alfred Rene
New York: John Wiley & Sons, 1978
548.5 UBB m
Buku Teks  Universitas Indonesia Library
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Glusker, Jenny Pickworth
New York: Oxford University Press, 1985
548 GLU c
Buku Teks  Universitas Indonesia Library
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Oxford: Pergamon Press, 1980
548.5 CRY
Buku Teks  Universitas Indonesia Library
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Crystal, Jill
Kuwait: Westview Press, 1992
953.6 CRY k
Buku Teks SO  Universitas Indonesia Library
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Nasution, Abdillah Imron
"Fluorosis is a condition due to ingestion of excessive amounts of flour which can cause the change in tooth structure and strength. However, there is still lack of explanation on the surface structure of crystal hydroxyapatite that influences the microscopic characteristic of fluorosis enamel. Objectives: To investigate the surface structure of crystal hydroxy-apatite in fluorosis enamel. Materials and methods: Determination of fluor concentration and the surface structure of normal and fluorosis enamel specimen were carried out by using Scanning Electron Microscopy/ Energy Disperse X-Ray (SEM/ EDX). Results: Fluor concentration of fluorosis enamel was significantly higher with increased surface roughness and porosity than normal enamel. SEM observation also showed gaps areas between enamel rods and visible aprismatic zone in some regions. Conclusion: High level of fluor concentration on fluorosis enamel indicated the subtitution of OH- by F- increasing the surface roughness of enamel surface."
Lengkap +
Jakarta: Fakultas Kedokteran Gigi Univerversitas Indonesia, 2009
AJ-Pdf
Artikel Jurnal  Universitas Indonesia Library
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Ladd, M.F.C.
Chichester: Ellis Horwood, 1979
541.224 LAD s
Buku Teks SO  Universitas Indonesia Library
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Isnaeni
"Two-dimensional photonic crystal structures not only confine light and guide waves laterally but also reflect light in the
normal direction due to a slow Bloch mode effect. However, evidence of the utilization of this structure as a mirror is
required. Therefore, in this work, a simulation was made and experimental results were obtained to prove that there was
an increase in the intensity of reflected CdSe colloidal quantum dots emission in the normal direction when a 2D
photonic crystal structure was used. A thin TiO2 film was shaped into a two-dimensional photonic crystal structure using
a simple sol-gel and polystyrene-mask-etching procedure. This structure was then placed on top of the thin CdSe
quantum dots film layer. The emission of quantum dots onto the two-dimensional photonic crystal structure was
compared to quantum dots emission onto a flat, thin TiO2 film. An increase in the quantum dots emission of up to 105%
was in the presence of the two-dimensional photonic crystal structure. This finding is very useful for photonic device
applications, such as light-emitting diodes, laser systems and bio-tagging detection systems.
Studi Simulasi dan Eksperimen Struktur Kristal Fotonik Dua Dimensi sebagai Pemantul Emisi Kuantum Dot
Masalah Arah Normal. Kristal fotonika dua dimensi tidak hanya dapat mengukung cahaya dan memandu gelombang
ke arah sisi horizontal, tapi juga mampu memantulkan cahaya ke arah normal dikarenakan efek moda slow Bloch .
Namun bukti tentang penggunaan stuktur ini masih dibutuhkan. Untuk itu dalam penelitian ini hasil simulasi dan
percobaan telah didapatkan untuk membuktikan bahwa terjadi peningkatan pantulan emisi CdSe kuantum dot colloid
pada arah normal saat kristal fotonika dua dimensi digunakan. Sebuah lapisan tipis TiO2 dibentuk menjadi kristal
fotonika dua dimensi denga menggunakan teknik sol-gel yang sederhana dan etching dengan menggunakan
polystyrene. Struktur ini diletakkan di atas lapisan kuantum dot CdSe. Emisi dari kuantum dot di atas kristal fotonika
dua dimensi dibandingkan dengan emisi kuantum dot di atas lapisan tipis dan datar TiO2. Peningkatan emisi kuantum
dot hingga mencapai 105% berkat kehadiran kristal fotonika dua dimensi. Hasil ini sangat berguna untuk aplikasi
divais fotonika seperti LED, sistem laser dan sisten detesi bio-tagging."
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Indonesian Institute of Sciences, Tangerang. Research Center for Physics, 2016
J-Pdf
Artikel Jurnal  Universitas Indonesia Library
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Parikin
"Microstructural identification of synthesized steel with significant local content has been carried out. Alloy ingot was prepared using a casting technique. The samples were then formed into bulk steel by a machining process. A high resolution powder neutron diffractometer (HRPD) was used as an equipment for characterization. By applying neutron diffraction techniques, a ferritic steel profile can be resulted in as well as ‘minor peaks’ belong to impurities formed in the sample. These impurities can be identified as small amounts of Al2O3 54SiO2, Al4C3, SiC and Cr23C6. Scanning transmission electron microscopy (STEM) combined with energy dispersive X-ray spectroscopy (EDX) confirmed and revealed neutron identified phase distributions. Joint Committee on Powder Diffraction Standards (JCPDS) least square curves calibration can precisely calculate the dhkl parameters of each reflection plane. As a comparison, another sample of alloy ingot was also investigated using neutron diffraction. The pattern was free from crystal impurities. Rietveld refinements provide satisfactory goodness of fits Rwp = 10.42% and reliability factor S = 1.7. This was so-called a ‘real bulky’ sample of a 73Fe24Cr2Si0.8Mn0.1Ni ferritic steel alloy."
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Depok: Faculty of Engineering, Universitas Indonesia, 2018
UI-IJTECH 9:1 (2018)
Artikel Jurnal  Universitas Indonesia Library
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Bintang Mahaputra
"Zeolit disintesis dengan Structure Directing Agent (SDA) yang divariasikan untuk menghasilkan kondisi struktur pori dan kristal yang bervariasi. SDA berfungsi sebagai pembentuk rongga terbuka/berpori pada kristal zeolit dan juga dapat berperan sebagai kation yang mampu mengakselerasi proses nukleasi dan pertumbuhan kristal. SDA yang digunakan pada penelitian ini adalah etilendiamin, karbon, Metildietanolamin (MDEA) dan Ammonium Lauryl Sulfat (ALS). Hasil sintesis zeolit dikarakterisasi dengan menggunakan metode Brunaer Emmet dan Teller (BET) dan X-Ray Diffraction (XRD) untuk melihat pengaruh SDA terhadap struktur pori dan kristal.
Hasil karakterisasi zeolit yang disintesis dengan menggunakan variasi SDA menunjukkan luas permukaan, diameter pori, ukuran kristal yang berbeda untuk masing-masing sampel. Peningkatan %massa SDA yang dilakukan dapat memperbesar luas permukaan dan ukuran pori zeolit. Zeolit dengan EDA sebagai SDA dengan penambahan %massa 15% menghasilkan luas permukaan terbesar, struktur pori meso dan krisal nano. Zeolit dengan karbon dan penambahan %massa 10% menghasilkan luas permukaan terkecil dan struktur pori meso.

Zeolite was syntesized with variation of Structure Directing Agents (SDAs) and it resulted different pore and crystal structure. To gain such condition, synthesis and vary of Structure Directing Agent (SDA) needed. SDA could be used not only as a builder for pore structure and crystal structure and also acted as cation that could accelerate nucleation process and crystal growth. SDA used for this research are etyhlendiamine (EDA), carbon, methyldiethanolamine (MDEA) and Ammonium Lauryl Sulfate (ALS). Samples are characterized with Brunaer Emmet and Teller (BET) and X-Ray Diffraction (XRD) to see SDA's influence on zeolite's pore and crystal structure.
The result from this research are zeolites synthesized with various SDA showed different pore size, surface area and crystal size for each SDAs. Increasing SDA %wt could increase surface area and pore size of zeolite. Zeolite with EDA as SDA and 15%wt adding produces high surface area, mesoporous and nano-sized crystal. Zeolite with carbon as SDA and 10%wtadding produces smallest surface area and mesoporous.
"
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Depok: Fakultas Teknik Universitas Indonesia, 2013
S47644
UI - Skripsi Membership  Universitas Indonesia Library
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