Judul: Sensor Field Effect TransistorBerbasisNanoseratPolianilin untukMengukur Konsentrasi Gas Amonia
Abstrak: Gas sensors can be made of metal, metal oxide, organic conductive polymers. Gas sensors of organic conductive polymers have superiority such as showing good sensitivity to the vapors of organic compounds and can be used at room temperature. Polyaniline nanofiber as active layers of Field Effect Transistor (FET) sensor sensitive in responding to ammonia gas (NH3). This research consists of manufacturing and characterization of FET sensor and determine the sensitivity of the FET sensor. FET sensor is made by oxidizing silicon wafers (the type-p Si) as layer dielectric (SiO2) and coating polyaniline nanofiber on SiO2 layers. On the type-p Si layer isset with gate electrode while polyaniline nanofiber layer is set with drain and source. When the FET sensor is given with more negative gate voltage so that drain-source current increases. Sensitivity value of FET sensor at Vg = 0 V is obtained 3.4215 V/% and Vg = -5 V is obtained 3.9018 V/%. The sensitivity test results showsmore and more negative gate voltage is given to be the greater the greater sensitivity value.
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Judul: Pembuatan dan Karakterisasi Sensor Gas Amonia Berbasis Polianilin
Abstrak: Prinsip kerja sensor gas amonia (NH3) berbasis polianilin (PANI) yaitu lapisan tipis PANI dikenai gas amonia. Perubahan sifat listrik lapisan tipis PANI dimanfaatkan sebagai sensor pendeteksi gas. Variasi konsentrasi dopant HCl pada sintesis dengan cara kimia biasa berpengaruh pada sifat listrik polianilin. Berdasarkan data hasil percobaan, semakin besar konsentrasi gas amonia yang diberikan resistansi PANI semakin kecil. Semakin besar konsentrasi gas amonia yang diberikan maka konduktansi PANI semakin tinggi. Variasi dopant HCl berpengaruh terhadap kinerja sensor, yaitu mempengaruhi tegangan jatuh sensor setelah dikenai gas amonia. Konsentrasi dopant yang lebih tinggi menghasilkan tegangan jatuh yang perubahannya lebih besar dibandingkan dengan konsentrasi dopant yang lebih rendah.
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Judul: Revision of Rhynchoglossum (Gesneriaceae) in Malesia
Abstrak: Revision on Rhynchoglossum in Malesia has been done. This research conducted based on morphological characters of 233 sheets of Herbarium specimen and Herbarium specimen photographs from Herbarium Bogoriense (BO), Singapore Botanic Gardens (SING), National Herbarium Netherlands (L), Royal Botanic Garden Kew (K), Natural History Museum London (BM), Royal Botanic Garden Edinburgh (E), New York Botanical Gardens (NY), Smithsonian Institute (US), and Harvard University (A). The result shows that six species are recognized in Malesia and five are endemic. Five species are known previously namely R. borneense, R. klugioides, R. medusothrix, R. obliquum, and R. spumosum; one species is proposed as a new and newly described namely R. celebicum. Rhynchoglossum borneense and R. medusothrix endemic to Borneo, R. celebicum endemic to Sulawesi, while R. spumosum endemic to Philippine Islands. Rhynchoglossum klugioides and R. obliquum distributed wider in Malesia. Rhynchoglossum papuae and R. merrilliae are placed under synonym of R. obliquum and R. spumosum. A phylogenetic analysis using PAUP version 4.0 program based on 60 morphological characters with Stauranthera coerulea and Loxonia hirsuta as an outgroup was undertaken. The analysis resulted a parsimonious tree which shown that Rhynchoglossum in Malesia can be divided in two groups. First clade consist R. obliquum, R. spumosum and R. celebicum while the second clade consist R. klugioides, R. borneense and R. medusothrix. Taxonomic treatment was giving with a identification key to the species, description, nomenclature, distribution, and notes each species.
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