Judul: Pemodelan dua potensial penghalang tidak simetris pada semikonduktor superlattice
Abstrak: Salah satu penomena menarik yang dapat dijelaskan fisika kuantum yaitu tunneling (penerobosan). Pada penomena ini, partikel yang bergerak dengan energi lebih kecil dari potensial penghalang memiliki probabilitas menerobos penghalang tersebut. Besarnya probabilitas dinamakan koefisien transmisi. Semikonduktor superlattice merupakan generasi baru dalam material semikonduktor yang diusulkan secara teoritis pada tahun 1970-an oleh Esaki dan Tsu. Superlattice memiliki struktur potensial penghalang dan sumur kuantum yang berselang-seling. Oleh karena itu, peristiwa tunneling akan menentukan karakteristik material tersebut. Dalam penelitian ini, dimodelkan dua potensial penghalang untuk mempelajari karakteristik superlattice dua penghalang tidak simetris yaitu GaAlAs-GaAs-GaAlAs dan AlAs-GaAs- AIAS. Parameter struktur seperti lebar potensial penghalang, lebar sumur dan ketinggian potensial penghalang/fraksi mol dipelajari bagaimana pengaruhnya pada karakteristik material tersebut. Hasil penelitian menunjukan bahwa lebar sumur merupakan parameter struktur penting karena lebar sumur yang divariasikan menunjukan hasil menarik terhadap koefisien transmisi dan karakteristik rapat arus-tegangan. Pada koefisien transmisi, pertambahan lebar sumur mengakibatkan penurunan tingkat energi resonan pertama seperti yang ditunjukan pada gambar 11(e) dan 12(e) sedangkan pada karakteristik rapat-arus tegangan, mengakibatkan penurunan arus resonan tunneling (JRT). Pada superlattice GaAlAs-GaAs- GaAlAs untuk lebar sumur 6, 7, dan 8 nm dihasilkan JRT (maks) berturut-turut 1.67 x 108; 8,9 x 10'; dan 4,35 x 10' A m2. Pada superlattice AIAS-GaAs-AlAs untuk lebar sumur 6, 7, dan 8 nm dihasilkan JRT (maks) berturut-turut 8,85 x 106; 4,14 x 106; dan 2,21 x 106 A m². Untuk fraksi mol yang divariasikan yaitu 0,6; 0,7; dan 0,8, perhitungan pada GaAlAs-GaAs- GaAlAs menghasilkan JRT (maks) berturut-turut 3,76 x 10; 1,78 x 108; dan 9,05 x 10' A m².
Keyword: semikonduktor superlattice, persamaan schrödinger, koefisien transmisi

Judul: Pemodelan Tiga Potensial Penghalang Simetris Pada Semikonduktor Superlattice
Abstrak: Salah satu penomena menarik yang dapal dijelaskan oleh fisika kuantum yaitu penerobosan (tunneling). Pada penomena ini, partikel yang bergerak pada energi potensial penghalang memiliki probabilitas tertentu menerobos penghalang tersebut. Besarnya probabilitas dimllnakan koefisien transmisi. Semikonduktor superlattice merupakan generasi baru dalam material semikonduktor yang diusulkan secara teoritis pada talmn 1970-an oleh Esaki dan Tsu. Superlattice memiliki struktur potensial penghalang dan sumur kuantum yang berselang-seling. Oleh karena itu, peristiwa penerobosan akan dapat menentukan karakteristik material tersebut.
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Judul: Biology and ecology of the buffalo fly, haematobia exigua de meijere (diptera:muscidae)
Abstrak: The life history of the buffalo fly was observed at room temperature of 27°-29.5°C and at a relative humidity of 48-68 percent. The eggs hatched after 17-22 hours, with an average of 18 hours. First instar larvae measured 1.25 + 0.16 mm long and 0.27 + 0.037 mm wide. reach the second larval stage. It took 6-12 hours to the second instar larvae measured 2.676 +0.187 mm long and 0.353 +0.028 mm wide. The second instar took about 12-24 hours to reach the third larval stage. The third instar measured 6.833 + 0.189 mm long and 0.919 + 0.051 mm wide. It took about 2-3 days for the third instar to become pupae. Duration of the pupal stage was about 5-7 days before the adults emerged. Under laboratory condition, the buffalo fly completed its life cycle in 9.5 to 10.5 days, whereas under field condition it took 9-14 days with an average of 10.5 days. The growth ratio which was based on the measurements of the cephalo-pharyngeal skeleton of each instar was 1.797. The preoviposition period was 8-12 days and mating usually occurred on the 6th or 7th day. The longevity of the male was 29 days, whereas it was 32 days in the female. The range of egg production under laboratory condition was between 20-139 per female fly. The belly and hind legs of the carabao were the most preferred habitat either during cloudy and cool dry or shiny and warm day. When the weather was clear and the carabao was in the shade, the flies tended to be more distributed particularly on the shoulder, dewlap, back and horns. The carabaos had relatively fewer Musca sp. and Stomoxys calcitrans than cattle; never the less carabaos had a higher infestation of buffalo fly than cattle. Oviposition occured either during the day or night but the buffalo flies were more active during the night than in the day time. The effect of various lengths of exposure time of manure in relation to the oviposition was profound. observed, the maximum number of the buffalo flies was occurred when the dung was exposed for 30 minutes. With increasing time of exposure the number and variety of insects also increase. It was evident that Sepsidae and psychodidae were the most dominant insects emerging from the dung. The number of buffalo flies also increased with increasing
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