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
Keyword: 

Judul: Sifat optik film tipis bahan ferroelektrik BaTiO3 yang didadah tantalum (BTT)
Abstrak: Telah dilakukan penumbuhan film tipis BaTiO3 didadah 10% Tantalum oksida (BTT) dipreparasi di atas substrat gelas korning 7059 menggunakan metode chemical solution deposition (CSD). Film tipis dideposisikan dalam 5 kali pelapisan dengan metode spin coating pada kecepatan putar 3000 rpm selama 30 detik. Annealing dilakukan pada temperatur 300oC, 400oC dan 500oC selama 15 jam pada masing-masing film tipis terdeposisi. Sifat ferroelektrik film tipis BTT di karakterisasi dengan Radiant RT 66 A. Sifat optik film tipis BTT dikarakterisasi menggunakan UV-VIS HP 8452A Diode Array Spectrophotometer dan analisis dilakukan menggunakan metode Tauc plot. Ketebalan dan morfologi permukaan film tipis BTT dikarakterisasi dengan SEM JEOL model JSM-35C. Kristalinitas film tipis BTT dikarakterisasi dengan XRD Philips Analytical PW1710. Hasil karakterisasi ferroelektrik telah menunjukkan kurva histerisis yang menandakan munculnya sifat ferroelektrik film tipis BTT yang soften dimana nilai medan koersif berkisar pada orde 10-1. Hasil SEM menunjukkan morfologi permukaan film tipis yang relatif seragam serta ketebalan film tipis sebesar 0,327 µm; 0,997 µm; 0,675 µm untuk BTT bertemperatur anneal berturut-turut 300oC, 400oC dan 500oC. Hasil XRD menunjukkan munculnya fasa BTT dengan parameter kisi kubik BTT dengan temperatur anneal berturut-turut 300oC, 400oC, dan 500oC adalah 5,0763 Å; 5,0781 Å; 5,0637 Å. Grain size BTT dengan temperatur anneal berturut-turut 300oC, 400oC, dan 500oC adalah 22,2443 nm; 24,2314 nm; 23,2073 nm. Hasil analisis sifat optik menunjukkan bahwa hasil pengukuran transmitansi pada 18-95%, celah-pita energi optis Eopt sebesar 3,21 eV; 3,34 eV dan 2,94 eV untuk BTT bertemperatur anneal berturut-turut 300oC, 400oC dan 500 oC.
Keyword: BTT, film tipis, CSD, spin coating, celah-pita energi

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