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Observation of Tunneling Effects in Lateral Nanowire pn Junctions Purwiyanti, Sri; Udhiarto, Arief; Moraru, Daniel; Mizuno, Takeshi; Hartanto, Djoko; Tabe, Michiharu
Makara Journal of Technology Vol 18, No 2 (2014)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (699.187 KB) | DOI: 10.7454/mst.v18i2.401

Abstract

As electronic device dimensions are continuously reduced, applied bias conditions significantly change and the transport mechanisms must be reconsidered. Tunneling devices are promising for scaled-down electronics because of expected high-speed operation and relatively low bias. In this work, we investigated the tunneling features in silicon-oninsulator lateral nanowire pn junction and pin junction devices. By controlling the substrate voltage, tunneling features can be observed in the electrical characteristics. We found that the minimum substrate voltage required for tunneling to occur in pn junctions is higher as compared with pin junctions. The main cause of these effects relies in the difference between the doping profiles, since the pn junctions contain a co-doped region, while the pin junctions contain an i-layer.
Fiber Optic Ring Resonator Sensor Detection Technique Based on Spectral Intensity Integration Sidi Priambodo, Purnomo; Raharjo, Sasono; Witjaksono, Gunawan; Hartanto, Djoko
Makara Journal of Technology Vol 19, No 1 (2015)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (241.865 KB) | DOI: 10.7454/mst.v19i1.3027

Abstract

Resonant field phenomenon in optical ring resonator has been a major theme for various studies and can be used for various sensor applications. The spectral response shape changes are subjects to be discussed and analyzed for detection in optical sensor system. The spectral response changes are caused by various factors ranging from refractive index of the surrounding medium, medium loss due to absorption and scattering, and coupling variation between waveguides. These optical phenomena are mostly used for bio-sensor applications, since it is free from electromagnetic interference (EMI) and non-physically destructive. In this paper, we discuss our current research in developing optical bio-sensor in the form of a fiber optic ring resonator with monochromatic laser source based on spectral integration detection method, which is sufficiently sensitive and accurate.
SYNTHESIS OF CAOZNO NANOPARTICLES CATALYST AND ITS APPLICATION IN TRANSESTERIFICATION OF REFINED PALM OIL Yulianti, Cicik Herlina; Ediati, Ratna; Hartanto, Djoko; Purbaningtias, Tri Esti; Chisaki, Yoshifumi; Jalil, Aishah Abdul; Che Ku Hitam, Che Ku Nor Liana; Prasetyoko, Didik
Bulletin of Chemical Reaction Engineering & Catalysis 2014: BCREC Volume 9 Issue 2 Year 2014 (SCOPUS Indexed, August 2014)
Publisher : Department of Chemical Engineering - Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (524.493 KB) | DOI: 10.9767/bcrec.9.2.5998.100-110

Abstract

The CaOZnO nanoparticle catalysts with Ca to Zn atomic ratios of 0.08 and 0.25 have been successfully synthesized by co-precipitation method. The catalyst was characterized by X-ray Diffraction (XRD) analysis provided with Rietica and Maud software, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared spectroscopy (FT-IR), and its properties was compared with bare CaO and ZnO catalysts. The phase composition estimated by Rietica software revealed that the CaO catalyst consists of CaO and CaCO3 phases. The estimation of the particle size by Maud software, showed that the particle size of all catalysts increased by the following order: ZnO. © 2014 BCREC UNDIP. All rights reservedReceived: 1st January 2014; Revised: 10th March 2014; Accepted: 18th March 2014[How to Cite: Yulianti, C.H., Ediati, R., Hartanto, D., Purbaningtias, T.E., Chisaki, Y., Jalil, A.A., Hitam, C.K.N.L.C.K., Prasetyoko, D., (2014). Synthesis of CaOZnO Nanoparticles Catalyst and Its Application in Transesterification of Refined Palm Oil. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (2): 100-110. (doi:10.9767/bcrec.9.2.5998.100-110)][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.2.5998.100-110]
Design of Generating Dual Frequency Operation for Triangular Microstrip Antenna Using Electromagnetic Coupling Surjati, Indra; Rahardjo, Eko; Hartanto, Djoko
Makara Journal of Technology Vol 9, No 2 (2005)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (173.092 KB) | DOI: 10.7454/mst.v9i2.97

Abstract

A new design is proposed in this paper by applying a pair of slits using a microstrip feed line. Therefore the microstrip line feeding system is electromagnetically coupled to the patch. The antenna works at two different frequencies in the range from 2 GHz to 4 GHz (S band frequency). The results of the simulation shows that the dual frequency operation can be created when the slit width is 1 mm and the height of the slits ranges from 10 mm to 14 mm with inter slit distance of 3 mm, 5 mm and 7 mm as well.
SIMPLE: System Automatic Essay Assessment for Indonesian Language Subject Examination Ratna, Anak Agung; Budiardjo, Bagio; Hartanto, Djoko
Makara Journal of Technology Vol 11, No 1 (2007)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (146.34 KB) | DOI: 10.7454/mst.v11i1.120

Abstract

Evaluation of study of a student is a very important aspect of an educational process. Evaluation is aimed at measuring the level of student understanding of the given lecture materials. Measuring student understanding of the course material, using essay-type exam, is generally used as the evaluation tool. In this essay-type exam, the student has to answer questions using sentences, whereby choices of possible answers are not indicated. The student has to answer the questions with his/her sentences. The answers may vary, since it reflects the students  thoughts of the materials. One of the weaknesses of essay-type exam is the difficulty to grade the answers and it tends to be time consuming. Currently, automatic grading systems that may speed up the grading process, are being developed in many research institutions.The method used to grade, varies zorm one system to another, and one of the popular system is he Latent Semantic Analysis (LSA). LSA is a method of grading essay by extracting words and representing the sentence in the form of mathematical or statistical formulation, from a text with a relatively large number of words. The grade of the essay is determined, by matching the important words to a group of words prepared by the human rater. This paper describes an effort to developed LSA, enhanced with word weighting, word order and the word synonym to improve the accuracy of grading. This system is called SIMPLE. SIMPLE is used to grade answers using bahasa Indonesia. The exam is carried out on-line through the Web. From the experiments conducted, for small classes, the conformity of grade compared to the grade of human rater lies between 69.80 % - 94.64 %, and for medium size classes the conformity lies between 77.18 % - 98.42 % with the human rater. These results are roughly proportional with the result of LSA system, which grade essay given in English.
Two Element Microstrip Antenna Array with Defected Ground Structure Zulkifli, Fitri; Rahardjo, Eko; Asvial, Muhamad; Hartanto, Djoko
Makara Journal of Technology Vol 12, No 2 (2008)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (97.855 KB) | DOI: 10.7454/mst.v12i2.148

Abstract

This paper presents a two element microstrip antenna array using trapezium shape defected ground structure (DGS). The DGS is inserted in the ground plane between two elements of antenna array. Insertion of the DGS is intended to suppress the mutual coupling effect produced by antenna array. Simulation and measurement results were taken and compared between antenna array with and without DGS. Measurement results show that the antenna with DGS compared to antenna without DGS can suppress mutual coupling effect to 7.9 dB, improve the return loss to 33.29% from -30.188 dB to -40.24 dB and axial ratio bandwidth enhancement to 10 MHz. This bandwidth enhancement is achieved from frequency 2.63 GHz – 2.67 GHz for antenna without DGS and from frequency 2.63 GHz – 2.68 GHz for antenna with DGS. In addition, the DGS antenna also improved the antenna gain to 0.6 dB. The results show that the implementation of the trapezium DGS can improve the radiation properties of the antenna without DGS.
Analysis of Hole Lifetime in SOI MOSFET Single-Photon Detector Catur Putranto, Dedy; Du, Wei; Satoh, Hiroaki; Ono, Atsushi; Priambodo, Purnomo; Hartanto, Djoko; Inokawa, Hiroshi
Makara Journal of Technology Vol 17, No 1 (2013)
Publisher : Directorate of Research and Community Services, Universitas Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (369.827 KB) | DOI: 10.7454/mst.v17i1.254

Abstract

Hole lifetime in the silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistor (MOSFET) singlephoton detector was evaluated by the analysis of drain current histograms for different light intensities and substrate voltages. It was found that the peaks in the histogram corresponding to the larger number of stored holes grew as the gate bias decreased. This was attributed not to the increased light absorption efficiency or collection efficiency of the photo-generated holes, but to the prolonged hole lifetime presumably caused by the higher transverse electric field inside the body of SOI MOSFET.
PORE STRUCTURE AND MORPHOLOGY CHARACTERIZATIONS OF MESOPOROUS ZSM-5 SYNTHESIZED AT VARIOUS AGING TIME Hartanto, Djoko; Purbaningtias, Tri Esti; Fansuri, Hamzah; Prasetyoko, Didik
Jurnal ILMU DASAR Vol 12 No 1 (2011)
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (473.394 KB)

Abstract

Mesoporous ZSM-5 has been successfully synthesized at various aging time of 6, 12 and 24 h. Mesoporous ZSM-5 was synthesized using cetyltrimethylammonium bromide (CTABr) as a template. Synthesis was carried out hydrothermally with aging and crystallization temperature at 60oC and 150oC. XRD patterns of the resulted material showed diffraction lines at 2? = 23o and at small angle (2? < 5o) which is characteristic of the structure of ZSM-5 and the existing of the mesoporous material. It was found that crystallinity of the sample increased at longer aging time. The result of nitrogen gas sorption analysis showed that all samples have pore size about 3,8 nm. The porosity of ZSM-5 decreased with shorter of aging time. ZSM-5 synthesized at 6 h aging time has the highest porosity of 72.57%. Aging time also affected the particle size, the longer the aging time, the smaller the particle size. The particle size was ranging 1.25 ? 1.0 ?m.
CHARACTERIZATION AND COBALT DISTRIBUTION STUDY OF CERAMIC BODY SYSTEM : BOJONEGORO CLAY– FELDSPAR – QUARTZ Sulistya, Rohmat; Hartanto, Djoko; Murwani, Irmina Kris
Indonesian Journal of Chemistry Vol 6, No 2 (2006)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (401.446 KB) | DOI: 10.22146/ijc.21749

Abstract

The quality improvement of Bojonegoro Clay and the cobalt distribution on the surface of ceramic body system have been studied. The ceramic body system consists of Bojonegoro Clay, feldspar and quartz is optimized using a triaxial blend method. About 6 compositions among 15 compositions of synthesized ceramic bodies can be casted in plastic condition with plastic limit between 22 and 30%. It has been obtained that the optimum composition of the ceramic body is 57% clay, 14.5% feldspar, 28.5% quartz with the total shrinkage is 7 % and the modulus of rupture is 18.23 N/mm2. Cobalt is distributed homogenously on the optimum ceramic surface with 0.3 mm depth at optimum glaze firing temperature (1050 oC).   Keywords: Bojonegoro Clay, feldspar, quartz, ceramic body, cobalt distribution
PENATAAN PKL BEBAS BORAKS DAN FORMALIN MENUJU PRODUK UNGGULAN SEHAT DAN HIGIENIS Rosyidah, Afifah; Purwanti, Endang; Hartanto, Djoko; Murwani, Irmina Kris; Prasetyoko, Didik; Ediati, Ratna
QARDHUL HASAN: MEDIA PENGABDIAN KEPADA MASYARAKAT Vol 3, No 2 (2017): OCTOBER
Publisher : Universitas Djuanda Bogor

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (231.245 KB) | DOI: 10.30997/qh.v3i2.944

Abstract

PKL STEPULATION OF FREE STORE BORAKS AND FORMALIN TOWARDS HEALTHY AND HYGIENIC SUPERIOR PRODUCTS ABSTRACT The Community service is focused on getting healthy and hygienic food around the campus. In the early stages, the identification of food sold in street vendors around the campus, whether it contains borax and or formalin. If the results of identification are still found foods containing borax and or formalin, then counseling and guidance and given about alternative materials borax and or formalin, which is safe for health. 40 food samples were random taken from street vendors around the campus. The content of formalin and borax is analyzed qualitatively and quantitative using test equipment’s. The results showed that there were 3 food samples from street vendors serving meatballs and noodles containing formalin and 5 food samples from street vendors serving food containing borax.Keywords: borax, formalin, qualitative analysis. ABSTRAK Layanan Masyarakat difokuskan untuk mendapatkan makanan sehat dan higienis di sekitar kampus. Pada tahap awal, identifikasi makanan yang dijual oleh PKL di sekitar kampus, apakah mengandung boraks dan atau formalin. Jika hasil identifikasi masih ditemukan makanan yang mengandung boraks dan atau formalin, maka konseling dan bimbingan dan diberikan tentang bahan alternatif boraks dan atau formalin, yang aman untuk kesehatan. Sebanyak 40 sampel makanan diambil secara acak dari pedagang kaki lima di sekitar kampus. Kandungan formalin dan boraks dianalisis secara kualitatif dan kuantitatif dengan menggunakan alat uji. Hasil penelitian menunjukkan bahwa ada 3 sampel makanan dari pedagang kaki lima yang menyajikan bakso dan mie yang mengandung formalin dan 5 sampel makanan dari pedagang kaki lima yang menyajikan makanan yang mengandung boraks.