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INDONESIA
Jurnal Matematika & Sains
Published by Institut Teknologi Bandung
ISSN : -     EISSN : -     DOI : -
Core Subject : Education,
Mathematics
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Articles 339 Documents
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Penumbuhan Film Tipis Ti1-xCoxO2 Dengan Metode MOCVD Horasdia Saragih; Mersi Kurniati; Akhiruddin Maddu; Pepen Arifin; Moehamad Barmawi
Jurnal Matematika & Sains Vol 9, No 3 (2004)
Publisher : Institut Teknologi Bandung

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Abstract

The Ti1-xCoxO2 thin films have been successfully deposited on Silicon (Si) substrates by metalorganic chemical vapor deposition (MOCVD). The Ti1-xCoxO2 thin films with x = 0 is grown at deposition temperature of 450oC with argon and oxygen flow rate of 100 sccm and 60 sccm, respectively. The deposited film has a single orientation of (213)-anatase. The films consist of nanometer size of columnar grains. The growth rate was increased with increasing Co content and therefore the grains become larger. Generally, the crystal structure of films was affected by Co atom concentrations, however at temperature deposition of 450oC and argon flow rate of 70 sccm, the film has the initial structure of (213)-anatase and co-exist with (301)-anatase which is not dominant. The film thickness is about of 0,9 μm for an area of 3x3 cm2.
Kapasitor MOS dengan dielektrik Ceria Amorf Khairurrijal Khairurrijal; Darsikin Darsikin; Maman Budiman
Jurnal Matematika & Sains Vol 9, No 3 (2004)
Publisher : Institut Teknologi Bandung

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Abstract

Amorphous ceria (CeO2) thin films were deposited on a silicon (100) substrate by using a pulsed-laser ablation deposition (PLAD) technique. The substrate temperature was varied from 600 to 7000 C and the ambient was a pure oxygen gas at the pressure of 100 mTorr. It was found that the growth rate is 17.5 nm/min. Low fixed-charge densities (1011/cm2) and high resistivies (109-1012 Ω cm) of the CeO2 thin films indicate that the films could be used for oxide layer of metal-oxide-semiconductor (MOS) capacitors. Electron conduction mechanism in the CeO2 thin films is ohmic at voltages below 1 V while that at voltages above 1 V are due to quantum tunneling process.
Analisis Hubungan Frekuensi-Magnitudo Gempa Bumi di Bali dan Sekitarnya Wandono Wandono; Sri Widiyantoro; Gunawan Ibrahim; Edy Soewono
Jurnal Matematika & Sains Vol 9, No 3 (2004)
Publisher : Institut Teknologi Bandung

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We mapped the 3-D b-value variation in Bali and its vicinity through analyzing the frequency-magnitude relation. A high b-value anomaly is observed beneath the Lombok volcanic arc at 90-180 km depth interval. It is related to the zone of partial melting of basaltic magma on the subducted slab of Indian oceanic plate beneath the Eurasian plate in Nusa Tenggara Barat. This analysis supports the hypothesis about the existence of melting point on the slab.
Sintesis dan Karakterisasi Senyawa BerstrukturAurivillius Empat dan Lima Lapis dan Penentuan Sifat Feroelektriknya Edi Mikrianto; Ismunandar Ismunandar
Jurnal Matematika & Sains Vol 9, No 3 (2004)
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Aurivillius oxides with composition of Na0,5Bi4,5Ti4O15 (NBT), K0,5Bi4,5Ti4O15 (KBT), Sr4Bi2Nb2Ti3O18 (SBNT), Ba4Bi2Nb2Ti3O18 (BBNT)and Bi5Ti5FeO18 (BTF) have been synthesised using the solid state reaction. The obtained oxides were polycrystalline. All the oxides were white, except that Bi5Ti5FeO18 was brick red in colour. Structure type determination was carried out using Phasanx software and PDF data base. It can be concluded that all oxides adopted orthorhombic crystal system and space group A21am with unit cell parameter a = 5.427(2) Å , b = 5.459(3) Å and c = 40.78(2) Å for Na0,5Bi4,5Ti4O15; a = 5.430(1) Å, b = 5.5258(6) Å and c = 50.747(5) Å for K0,5Bi4,5Ti4O15 ; a = 5.5439(9) Å ; b = 5.5258(6) Å and c = 50.747(5) Å for Sr4Bi2Nb2Ti3O18 ; a = 5.540(2) Å, b = 5.579(4) Å and c = 50.962(8) Å for Ba4Bi2Nb2Ti3O18 ; whilst for Bi5Ti5FeO18 a = 5.520(1) Å, b = 5.569(3) Å and c = 50.36(1) Å. Ferroelectric properties measurement showed that polarization remanent Pr(+) and Pr(-) 0.049 μCcm-2 for Na0,5Bi4,5Ti4O15 ; 0.051 μCcm-2 for K0,5Bi4,5Ti4O15; 0.045 μCcm-2 for Sr4Bi2Nb2Ti3O18; 0.050 μCcm-2 for Ba4Bi2Nb2Ti3O18 and 0.050 μCcm-2 for Bi5Ti5FeO18.
SINTESIS FAUJASITE DARI ABU LAYANG BATUBARA : Pengaruh Refluks dan Penggerusan Abu Layang Batubara terhadap Kristalinitas Faujasite Sutarno Sutarno; Yateman Arryanto; Arief Budhyantoro
Jurnal Matematika & Sains Vol 9, No 3 (2004)
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Synthesis of Faujasite from coal fly ash has been conducted which involved reflux, grinding fusion and hydrothermal reaction. Coal fly ash is refluxed with hydrochloric acid 5 M at 90 oC for 5 hours. Grinding effect of refluxed coal fly ash on Faujasite synthesis has been studied as other variable on synthesis of Faujasite. Coal fly ash is mixed with NaOH pellet which NaOH : coal fly ash ratio = 1.2, and then fused at 550 oC for 1 hour. Fused coal fly ash is mixed with 100 ml distilled water, stirred and aged for 24 hours. The resulted solution was then reaeted with hydrothermal bomb autoclave at 100 oC for 3 days. The result was characterized with X-ray diffraction using diffractometer shimadzu 3001. The experimental data showed that coal fly ash refluxed with hydrochloric acid 5 M increased in Si/Al ratio of coal fly ash. Synthesis of Faujasite with coal fly ash refluxed with HCl 5 M as raw material produced good crystallinity Faujasite, but the used of unrefluxed coal fly ash as raw material on synthesis of zeolite gave hydroxysodalitet. Synthesis of Faujasite from ungrand coal fly ash whichh is refluxed with HCl 5 M gave better Faujasite crystallinity than that of the grund one.
The Effects of Mass Loss on The Evolution of BD+60°2522 Aprilia Aprilia; Djoni N. Dawanas
Jurnal Matematika & Sains Vol 9, No 4 (2004)
Publisher : Institut Teknologi Bandung

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BD+60°2522 (V = 8.7 mag) is the ionizing star of NGC 7635, the so-called Bubble Nebulae – wind-blown bubble created by the interaction of the stellar wind of BD+60°2522 with the ambient interstellar medium. It is classified as an O6.5 IIIef with mass loss rate M76.510−ô€¾/year. The present mass of the star is 50 Mô€¾. We carry out evolutionary calculations for the star with and without mass loss and we find that the initial mass of the star is 63 Mô€¾ and its present age is years. The main sequence lifetime for BD+60°2522 is longer compared with that computed without mass loss; the difference is years. Comparing the mass and the age of NGC 7635 with BD+60°2522, we find that the bubble nebulae did not form since the ZAMS phase of the star.
Konsumsi Makan dan Pertumbuhan Larva Helicoverpa armigera Toleran terhadap Pemaparan Helicoverpa armigera Nuclear Polyhedrosis Virus (HaNPV) Yayan Sanjaya; Wardono Noloperbowo; Tjandra Anggraeni
Jurnal Matematika & Sains Vol 9, No 4 (2004)
Publisher : Institut Teknologi Bandung

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An investigation on the effect of repeated infection of Helicoverpa armigera Nuclear Polyhedrosis Virus (HaNPV) to Helicoverpa armigera to know its effect on Helicoverpa armigera tolerance had been carried out. On treatment with 800 (Polyhedral Inclusion Body/dose) PIB/dose indicated that the exposure of HaNPV to H. armigera larva showed no difference significantly (P> 0.05) on its LD50 to every generation exposed. In contrast, H. armigera which had been exposed by HaNPV had a higher food consumption and larval growth rate compared to H. armigera without treatment. This investigation also showed that the increasing food consumption and larvae growth rate of H. armigera was in line with the increase of HaNPV exposure. Infection of HaNPV caused a development of tolerance mechanism in H. armigera.
Pengaruh Temperatur Penumbuhan Terhadap Karakteristik Magnetik Film Tipis TiO2:Co yang ditumbuhkan dengan Metode Metalorganic Chemical Vapor Deposition (MOCVD) Horasdia Saragih; Pepen Arifin; Moehamad Barmawi; Mersi Kurniati
Jurnal Matematika & Sains Vol 9, No 4 (2004)
Publisher : Institut Teknologi Bandung

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TiO2:Co thin films have been grown on p-type Si(100) substrates by MOCVD method. The films were grown at substrate temperature of 450 oC to 500 oC , and the temperature of precursor bubbler was kept constant at 50 oC with vapor pressure of 260 Torr. Flow rate of O2 and Ar are 60 sccm and 100 sccm, respectively. The crystal structure, grain shape and magnetic properties of the films depend significantly on the substrate temperature. The anatase-213 structure with columnar grain was formed for the films grown at temperatures of 400 oC and 450 oC. The arrangement of atoms at grain boundary is improved at growth temperature of 450 oC. Anatase-301 structure with cone grain shape as additional component appears at growth temperature of 500 oC. The TiCoO3 phase with 310 plane was found at growth temperature of 550 oC. The grains grow at direction of -45o from normal substrate. Films that grown at 450 oCand 500 oC exhibit soft magnetic properties with Hc of 100 Oe and 80 Oe; and Mr of 250 emu/cm3 and 220 emu/cm3, respectively. The hard magnetic properties of the films are shown for the films grown at 550 oC. The films were grown for 2 hours producing the films with thickness of about 0.7 to 0.9 μm.
Konstruksi Diagram Potensial-pH untuk Baja Karbon dalam Buffer Asetat secara Potensiodinamik Eksperimental Bunbun Bundjali; N. M. Surdia; Oei Ban Liang; Bambang Ariwahjoedi
Jurnal Matematika & Sains Vol 9, No 4 (2004)
Publisher : Institut Teknologi Bandung

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The pH-potential, or the so called Pourbaix, diagram for the system Fe - H2O is normally been constructed by using thermodynamic data. In this work the diagram was constructed experimentally based on potentiodynamic measurements of carbon steel in acetic acid - acetate ion buffer solutions at a temperature range of 25-85 0C. Due to the limited pH trajectory of buffer acetate solutions the resulted diagrams were not as wide pH as those of thermodynamic Pourbaix diagrams, but they are more useful for analysing carbon steel corrosion in acetate environment systems at that temperature range. In Addition the effects of pH and temperature on the primary passive potential (Epp) and Fladge potential (EF) relationship could also be obtained.
Sintesis dan Karakterisasi BaSrAl4O8, BaSrAl3FeO8, dan BaSrAl2Fe2O8 Darwin Ismail; Ismunandar Ismunandar
Jurnal Matematika & Sains Vol 9, No 4 (2004)
Publisher : Institut Teknologi Bandung

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Abstract

BaSrAl4O8, BaSrAl3FeO8 and BaSrAl2Fe2O8 oxides have been synthesized and their crystal structures type were determined by XRD diffraction. The diffraction patterns were very close to that of BaSrGa4O8, which has space group P63 (No. 173). All of the compounds have AlO4 tetrahedra (as GaO4), form the six-membered rings sharing corners, and the Ba and Sr atoms occupy large cavities of the six-member rings. Fe atoms possibly replace Al atom in the structure. From Proszki analysis in a hexagonal crystal system and P63 space group (No.173), the obtained cell parameters, a and c for BaSrAl4O8, BaSrAl3FeO8 and BaSrAl2Fe2O8 were successively as follows (8.984(2), 8.625(3)) Å; (10.377 (4), 8.619(5)) Å; and (10.454(3), 9.140(3)) Å. Based on ferroelectric properties obtained from RT-66A oscilloscope instrument, only BaSrAl3FeO8 compound exhibited a significant hysteresis loop pattern.

Page 15 of 34 | Total Record : 339

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