Judul: Sifat ferroelektrik film tipis Ba1-y/2(Ti1-yTay)O3(BTT)
Abstrak: Telah berhasil ditumbuhkan film tipis Ba1-y/2(Ti1-yTay)O3 (BTT) dengan metode chemical solution deposition (CSD). Digunakan spin coating dengan kecepatan putar 3000 rpm dalam waktu 30 detik, dilakukan 5 kali pelapisan. Penumbuhan film tipis BTT dilakukan diatas substrat Pt(200)/SiO2/Si(100) dan Si (100) tipe-p, dilakukan annealing pada suhu 900oC, 950 oC dan 1000 oC. Uji sifat ferroelektrik dilakukan dengan alat Radiant Technology model RT 66 A. Film tipis dengan sifat ferroelektrik yang terbaik adalah untuk penumbuhan film tipis BTT diatas substrat Pt(200)/SiO2/Si(100) untuk suhu annealing 1000oC dengan nilai polarisasi remanen, polarisasi saturasi dan medan koersif masing-mas ing 1,4709mC/cm2, 5,5970mC/cm2, dan 2,9832kV/cm. Kata kunci : ferroelektrik, CSD, BTT
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Judul: Uji sifat listrik dan sifat optik film tipis BaxSr1-xTiO3 (BST) yang dibuat dengan metode chemical solution deposition
Abstrak: Telah dilakukan penumbuhan film tipis Ba,SrTiO3 (BST) di atas substrat Si (100) tipe-p. Metode yang digunakan adalah metode chemical solution deposition (CSD) dengan teknik spin coating pada kecepatan putar 3000 rpm dalam waktu 30 detik. Pelapisan dilakukan hanya 3 lapisan untuk setiap substrat. Dibuat film tipis BST dengan variasi fraksi mol Barium (x=0.35, 0.40, 0.45) dan annealing pada suhu 850°. Hasil penelitian menunjukkan bahwa Film tipis BST merupakan bahan semikonduktor karena mempunyai nilai konduktivitas listrik antara 103 - 10 S/cm. Konduktivitas listrik film tipis akan semakin besar apabila intensitas penerangan lampu semakin tinggi. Nilai konstanta dielektrik akan semakin besar dengan semakin besarnya perubahan nilai fraksi mol Barium. Film tipis Bao.75 Sro,25 TiO3 (BST) yang telah ditumbuhi di atas Si tipe-p dapat berfungsi sebagai fotodioda.
Keyword: BST, CSD, Electrical conductivity, Dielectric constant, Bogor Agricultural University, Institut Pertanian Bogor, IPB

Judul: Phylogeography and Species Limits in the Papuan White Snake (Micropechis ikaheka) (Reptilia: Serpentes: Elapidae)
Abstrak: Papua white snake, Micropechis ikaheka, has been distingushed into two subspecies M.i. ikaheka and M.i. fasciatus. However, due to lack of data on their morphology, distribution and ecology, both subspecies often ignored in scintific discussions and refers only byas , Micropechis ikaheka. This study was designed to document the differences between M.i. ikaheka and M.i fasciatus by using scales characteristics and reproductive organ or hemipenes. The study also examine, zoogeography, habitat, diet and cannibalism of both subspecies to better understanding the the ecology of one of the most venomous snakes in the world. This study consists of three topics with method and also different in the size samples, respectively. The first study is the histology and microtopography of the skin were studied using paraffin method and Scanning Electron Microscope (SEM). The second is the hemipenis were examined by following Myers and Cadle (2003), and Zaher and Prudente (2003). The third is the abdominal surgery was carried out to document diet type and the investigate phenomenon of cannibalism in the snake. Specimens for this study came from the collection from Museum Zoologicum Bogoriense (MZB) and Universitas Negeri Papua’s Laboratory (LZU). The research result also indicated that the markers of skin and hemipenis described the same structure and microornamentation in all M. ikaheka groups being compared. Based specimens examined morphological descriptions do not s support the further differentiation in Micropechis. In short, two markers that used in this study could not sufficiently indicate the differences in the level of species and subspecies of M. ikaheka. The study, however, were able to delineate zoogeography and skin color patterns, which fall into four groups: M. i. ikaheka; M. i. fasciatus. M. i. ssp. “intermediate”; and M. i. ssp “black”. This study also revealed that color variations did not overlap in their geographic distribution. It is therefore, it suggested that environmental factors may contribute to the skin color variations. It also assumed that habitat discontinuous and biogeography factors may also cause the loss of the connection between the original populations (vicarians) or follow colonization events (dispersal). The examined of 22 stomach contents of M. ikaheka shows this species is carnivorous, and prey on vertebrates such as amphibians, fish, reptiles, and Mammals. These snakes are opportunistic predators since they prey on all that can be captured, but mainly reptiles (61.5%), followed by mammals and fish (both 15.4%), and amphibians (7.7%). Although categorized as terrestrial animal, the diet study showed that M. ikaheka snakes often go into the water to hunt for fish (the sample from Yapen island), including eel (the sample from Aru island). Based on prey items indentified, there is evidence that M. ikaheka is cannibal. At this time, there still no record on reason for cannibalism, but it is assumed that cannibalism was due to competition between populations and means to control population.
Keyword: geographic variation, white snake, papua