Judul: Optical Properties and Crystal Structure  of Ferrum-doped Barium Titanate (BaTiO3) thin film.
Abstrak: Film tipis Barium Titanat didadah Ferrum telah berhasil disintesis menggunakan metode chemical solution depositioni (CSD) dan teknik spin coating. Film dibuat dengan mendeposisikan laruta kimia 2M pada substrat Si (100) tipe-p, lalu diputar menggunakan piringan spin coater pada kecepatan 3000 rpm dalam waktu 60 detik dan proses pendeposisian ini dilakukan sebanyak 5 kali. Sifat optik berdasarkan karakterisasi UV-Vis menunjukkan bahwa semakin tinggi konsentrasi Ferrum di dalam film Barium Titanat (0%; 0,5%; 1%) nilai reflektansinya akan semakin meningkat dan nilai band gap yang diperoleh menurun dari 2,8 eV – 2,4 eV. Jarak antara fonon optik longitudinal dan optik transversal mengecil seiring bertambahnya konsentrasi Ferrum. Hasil karakterisasi XRD menunjukkan parameter kisi yang menurun seiring dengan meningkatnya konsentrasi Ferrum di dalam film Barium Titanat, karena jari-jarik ionik atom Ferrum (0,77 Å) lebih kecil dibandingkan jari-jari Barium (1,36 Å)., Fe-doped Barium Titanate thin film in has been successfully synthesized using chemical solution deposition (CSD) method and spin coating technique. The film was made by depositing a 2M chemical solution on a p-type Si(100) substrate, then spin it using a spin coater plate at 3000 rpm for 60 seconds and this deposition process was carried out 5 times. The optical properties based on UV-Vis characterization show that the higher the concentration of Ferrum in the Barium Titanate film (0%; 0,5%; 1%) the reflectance value will increase and the band gap value decrease from 2,8 eV – 2,4 eV. The distance between the longitudinal and transverse optical phonons decrease on increasing the concentration of Ferrum. The XRD characterization results show that the lattice parameters decrease on increasing Ferrum concentration in the Barium Titanate film, because the ionic radius of the Ferrum atom (0,77 Å) is smaller than that of Barium atom (1,36 Å).
Keyword: barium titanat, energi bandgap, mode fonon, parameter kisi, bandgap energy, barium titanate, lattice parameters, phonon mode

Judul: Synthesis and Characterizations of Barium Titanate (BaTiO3) Thin Film with Varied Concentration of Iron (II) Acetate (Fe(CH3COO)2) as Dopant
Abstrak: Sintesis film tipis BaTiO3 dengan variasi konsentrasi pendadah Fe (0%; 2%; 4%; dan 6%) menggunakan metode chemical solution deposition (CSD) berhasil dilakukan. Larutan sampel dideposisikan di atas substrat silikon (100) tipe-p dengan teknik spin coating pada kecepatan anguler 8000 rpm selama 60 detik. Proses annealing dimulai pada suhu kamar hingga mencapai suhu 850°C dan ditahan selama 8 jam dengan kelajuan suhu sebesar 1,67°C/menit, dilanjutkan dengan pendinginan hingga suhu kamar selama 12 jam. Ketebalan film dihitung dengan metode volumetrik dan hasilnya berturut-turut yaitu 3,9867 μm; 3,8759 μm; 3,6913 μm; dan 3,0454 μm. Analisis dengan persamaan Cramer-Cohen menghasilkan parameter kisi a = b yaitu 3,843 Å; 3,882 Å; 3,898 Å; dan 3,909 Å serta parameter kisi c yaitu 4,002 Å; 3,938 Å; 4,070 Å; dan 4,024 Å dengan struktur kristal tetragonal. Nilai enegi band gap hasil analisis dengan fungsi Kubelka Munk untuk indirect transition berada dalam rentang 3,0689 – 3,2051 eV dan direct transition berada dalam rentang 2,7660 – 3,0417 eV., The synthesis of BaTiO3 thin film with variations in concentration of Fe as dopant (0%; 2%; 4%; and 6%) using chemical solution deposition (CSD) method has been successfully done. The solutions was deposited on p-type silicon (100) substrates with spin coating technique at the angular speed of 8000 rpm for 60 seconds. The annealing process was started at room temperature until 850°C and was held for 8 hours with a temperature speed of 1.67°C/minutes, followed by cooling process to room temperature for 12 hours. Film thickness was calculated using volumetric method and the results are 3.9867 μm; 3.8759 μm; 3.6913 μm; and 3.0454 μm. The results of the analysis using Cramer-Cohen equation obtained that the lattice parameters a = b are 3.843 Å; 3.882 Å; 3.898 Å; and 3.909 Å and c are 4.002 Å; 3.938 Å; 4.070 Å; and 4.024 Å with tetragonal crystal structure. The values of band gap energy that was analyzed using Kubelka-Munk method equation are in range of 3.0689 – 3.2051 eV for indirect transition and 2.7660 – 3.0417 eV for direct transition.
Keyword: thin film, barium titanate, cramer-cohen, kubelka-munk, dopant

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