Judul: Sifat optik film tipis Ba0.5Sr0.5TiO3doping Fe2O3
Abstrak: Telah dilakukan penumbuhan film Ba0.5Sr0.5TiO3 1 M doping Fe2O3 10 % diatas gelas Corning dengan metode Chemical Solution Desposition (CSD). Karakterisasi film dilakukan untuk menentukan besar celah optik dengan variasi suhu 300 oC, 400 oC dan 500 oC. Hasil karakterisasi X-Ray Diffraction (XRD) memperlihatkan bahwa film belum menunjukan struktur mikrokristalin untuk semua variasi suhu hal ini dikarenakan film Ba0.5Sr0.5TiO3 baru akan maksimal terbentuk struktur mikrokristalin sempurna pada suhu 800 oC. Hasil karakterisasi Scanning Electron Microscope(SEM) memperlihatkan tebal film tipis untuk suhu 300 oC, 400 oC dan 500 oC 0.097 μm, 0.418 μm dan 0.25 μm. Besar celah energi optik yang terbentuk sebesar 3.11 eV untuk BFST dengan suhu annealing 300oC, Eg 3.51 eV untuk BFST dengan suhu annealing 400oC dan 3.46 eV untuk BFST dengan suhu annealing 500oC. . Kata kunci : CSD, Annealing
Keyword: 

Judul: Uji sifat listrik dan struktur kristal fotodioda ba0,5sr0,5tio3 dengan variasi pendadahan fe2O3
Abstrak: Ba0,5Sr0,5TiO3 (BST) thin film was doped by Ferium (Fe2O3) has been done with doping variation 2.5%, 5%, 7.5% and 10% above the substrate Si (100) p-type using chemical solution deposition (CSD) methods by spin coating technique at 3000 rpm for ± 30 seconds. Ba0,5Sr0,5TiO3 thin film made with 1 M concentration and the annealing temperature by 850oC. The results of current-voltage (I-V curves) characterization shows that the BST thin film and BFST are photodiodes. Electrical conductivity values BST and BFST thin films are in the range of semiconductor materials and obtain the electrical conductivity increased when the higher intensity light is used. The result of the dielectric constant increases with the addition of Fe2O3 doping. SEM results showed that the BST and BFST material is a thin film with thickness of the order 10-6 m. Result of XRD showed that BST and BFST is cubic.
Keyword: 

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