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"ABSTRAKSuatu penelitian telah dilakukan di laboratorium basah, Balai Penelitian Perikanan Air Tawar Bogor, dimulai tanggal 20 Agustus sampai dengan 1 Desember 1991. Penelitian ini bertujuan untuk melihat pengaruh bahan organik dalam air terhadap pertumbuhan bakteri bercahaya pada pemeliharaan larva udang windu. Juga untuk rnengetahui Pertumbuhan jumlah bakteri dan mortalitas larva udang windu.Percobaan ini dilakukan dengan menggunakan rancangan acak lengkap (RAL) dengan enam perlakuan konsentrasi bahan organik dan tiga kali ulangan. Perlakuan tersebut adalah 0 ppm(A) sebagai kontrol, 15 ppm(B), 30 ppm(C), 45 ppm (D), fi0 ppm (E) dan 75 ppm (F.).Sebanyak 100 ekor larva udang windu stadia nauplius di masukkan ke dalam bak akuarium yang telah diberi perlakuan konsentrasi bahan organik. Isolasi bakteri bercahaya juga dinokulasikan ke dalam bak akuarium dengan kepadatan 103 sel per ml.Pengarnbilan contoh bakteri dan air dilakukan setiap hari selama lima hari. Idetifikasi bakteri menurut metoda Cowen & Steel 1974: 17-20) ; West & Colwell (1984: 285-289). Fisika dan kirnia air seperti oksigen terlarut, karbondioksida, total bahan organik, ammonia, pH, salinitas dan temperatur air di ukur dengan menggunakan metoda standar.Hasil penelitian menuniukkan bahwa konsentrasi bahan organik dalam air meningkat sesuai dengan rataan konsentrasi bahan organik yang dimasukkan ke dalam bak percobaan saat awal. Peningkatan konsentrasi bahan organik dalam air ternyata rata-rata meningkat. Puncak konsentrasi bahan organik perlakuan E dan F dicapai pada hari kedua sedngkan perlakuan A dan S terjadi pada hari kelima. Konsentrasi bahan organik dalam air berbeda sangat nyata terhadap pertumbuhan bakteri, bercahaya dalam air dan pada larva udang windu (P> 0.01). Jumlah total bakteri dan bakteri bercahaya lebih tinggi pada konsentrasi bahan organik yang lebih besar.Rataan jumlah kaloni bakteri pada masing-masing konsentrasi bahan organik adalah 103.44; 99.4; 82.81 dan 82.32. Mortalitas larva udang windu lebih tinggi pada perlakuan konsentrasi bahan organik yang lebih besar. Mortalitas tersebut berturut-turut adalah 80.33%; 68.66%; 22.3%; 15.0% dan 2.3% untuk perlakuan F, E, D, C, B dan A.Karakteristik fisika dan kimia air adalah sebagai berikut : oksigen terlarut 4.8-7.4 ppm; CO2 0-19.36 ppm; NH3 0.025-0.175 ppm; pH 7-8 ppm; temperatur air 30-31°C dan salinitas 30-32%.

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ABSTRACT

An experiment was conducted at the Research Institute for Freshwater Fisheries's wet laboratory in Bogor from 20 August to 1 December, 1991. This study was done to evaluate the effect of organic matter in water to the population growth of luminescent vibrio on Penaeus monodon larval. The total number of bacterial population and the mortality of the shrimp larvae were also evaluated.

In this study a complete randomized design (CRD) was used with six different concentrations of organic matter as treatments and three replication. The treatments were 0 ppm(A) as a control, 15 ppm(B), 30 ppm(C), 45 ppm(D), 60 ppm(E) and 75 ppm(F).

One hundred shrimp larvae at nauplius stage were stocked in each aquarium contained the respective organic matter concentration.

The luminous vitro isolate were also inoculated in each aquarium at a concentration of 10 cell per ml. Sample of bacteria and water were taken every day for 5 days. The bacteria were identified according to Cowan & Steil method (1974:17-20): West & Colwell (1984:285-289). Physical and chemical of the water such as dissolved oxygen, carbon dioxide. total organic matter, ammonia, pH, salinity and water temperature were examined by the standard water measurement method.

The results indicated that the concentration of organic matter in water increased proportionally relative to the rate of initial concentration used. The higher the initial organic matter concentration applied the higher increase rate of its concentration in the water. The peak of the concentration was reached faster at the higher concentration than the lower one. The peak of E and F treatment were at the second day while A and S treatment were at the fifth day. Organic matter content in water significantly effect on the population growth of bacteria both in water and in shrimp larvae (P>0.01). The number of total bacteria and the luminous vibrio were higher at a higher concentration of organic matter. The average number of bacterial colony count at the respective organic matter concentration were 103.44; 99.4; 82.81; and 82.32.

The shrimp larvae mortalities were also higher at the higher concentration of organic matter. The percent mortality rate were : 80.33%; 68.86%; 22.3%, 15.0%, and 2.3% for F,E,D,C,B and A treatments respectively.

The physical and chemical characteristic of the water are as follows: dissolved oxygen 4.8-7.4 ppm; CO2 0-19.36 ppm; NH3 0.025-0.175 ppm; pH 7-8; temperature 30- 31°C and salinity 30-32%."

"The aim of this study was to synthesize high luminescence materials containing the optimal combination of ternary europiumpicrate complex and matrices. The ternary europium-picrate-triethylene glycol (Eu-EO3-Pic) complex was doped in poly(methyl methacrylate), PMMA. The composites were impregnated in several matrices to form thin filmsvia spin coating technique. The microparticles of Eu-EO3-Piccomplex were prepared by reprecipitation-evaporation, then they were compared to analogous complex or microcomposite prepared by in-situ method. The Eu-EO3-Pic/PMMA microcomposites were characterized by fluorescence spectroscopy in acetone solution. The particle sizes distribution of microcomposites synthesized by reprecipitation-evaporation method (110.3 to 426.8 nm) were smaller compared to the microcomposites by in-situ method (641.7 nm). The PMMA was able to significantly enhance the fluorescence intensity of Eu-EO3-Pic microparticles. The fluorescence intensity of microcomposite by in situ-preparation was lower than that found in the microcomposites by reprecipitation-evaporation method. We also investigated the effect of different matrices on the photophysical properties. The effective intermolecular energy transfer from PMMA to the Eu-EO3-Pic complex would produce high sensitization efficiency. These microcomposites are very potential used as the emission material for organic light emitting devices."

"ABSTRACTThe emergence of exitonic signal in the optical response of a wide band gap semiconductor has been a common knowledge in physics. There have been numerous experimental studies exploring the important role of excitons on influencing both the transport and optical properties of the materials. Typically, excitonic effect appears in the optical spectra of a wide band gap semiconductor as a rising signal below the onset energy of the band to band transition. Despite the existence of much information on excitonic effects, there has not been much literature that explores detailed theoretical explanation on how the exitonic signal appears and how it evolves with temperature. Here, we propose to do a theoretical study on the optical conductivity of ZnO, a well known wide band gap semiconductor that we choose as a case study. ZnO has been known to exhibit excitonic states in its optical spectra in the energy range of 3.13 3.41 eV, with a high exciton binding energy of 60meV. An experimental study on ZnO in 2014 revealed such a signal in its optical conductivity spectrum. Motivated to explain this phenomenon, we present a theoretical investigation on the appearance of excitonic signal in optical conductivity of ZnO. We model ZnO within an 8 band k.p approximation. We calculate the optical conductivity by incorporating the first order vertex correction derived from the Feynman diagram. We hypothesize that this first order vertex correction carries the information of how the optical spectral weight transfers from the region slightly above to the region slightly below the onset of band to band transition. We aim to see this effect at various temperatures. We expect to compare our calculation results with the existing experimental of the optical conductivity ZnO.

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ABSTRAKKemunculan sinyal eksiton pada respon optik sebuah semikonduktor celah lebar telah menjadi hal umum di dalam ilmu fisika. Beberapa penelitian telah melakukan studi terhadap pentingnya peran eksiton pada sifat-sifat transport dan optik suatu material. Umumnya efek eksiton yang terlihat pada spektrum optik semikonduktor celah lebar muncul dalam bentuk sinyal yang naik pada daerah di bawah onset energi transisi antar pita. Meskipun begitu, tidak banyak literatur teoritik yang membahas secara detail bagaimana sinyal eksiton terbentuk dan pengaruh temperatur terhadap sinyal tersebut. Pada penelitian ini kami menyajikan studi teoritik pada konduktivitas optik ZnO, yaitu semikonduktor celah lebar yang populer. ZnO diketahui memiliki states eksiton pada spektrum optik 3.13-3.41 eV dengan energi ikat eksiton sebesar 60meV. Studi eksperimen ZnO di tahun 2014 menunjukkan sinyal yang muncul pada spektrum konduktivitas optik. Diawali dengan motivasi untuk menjelaskan fenomena ini, kamu menyajikan studi teoritik pada kemunculan sinyal eksiton pada konduktivitas optik dari ZnO. Kami memodelkan ZnO dengan menggunakan pendekatan 8-band k.p theory. Perhitungan konduktivitas optik dilakukan dengan melibatkan koreksi vertex orde pertama yang diturunkan melalui diagram Feynman. Kami yakin bahwa koreksi vertex orde pertama membawa informasi bagaimana spektrum optik bergeser, dari sedikit di atas onset energi transisi antar pita menjadi di bawah onset energi transisi antar pita. Kami melihat efek ini pada temperatur yang berbeda-beda. Kami membandingkan hasil perhitungan kami dengan hasil eksperimen konduktivitas optik ZnO yang sudah ada."