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"Two-dimensional photonic crystal structures not only confine light and guide waves laterally but also reflect light in thenormal direction due to a slow Bloch mode effect. However, evidence of the utilization of this structure as a mirror isrequired. Therefore, in this work, a simulation was made and experimental results were obtained to prove that there wasan increase in the intensity of reflected CdSe colloidal quantum dots emission in the normal direction when a 2Dphotonic crystal structure was used. A thin TiO2 film was shaped into a two-dimensional photonic crystal structure usinga simple sol-gel and polystyrene-mask-etching procedure. This structure was then placed on top of the thin CdSequantum dots film layer. The emission of quantum dots onto the two-dimensional photonic crystal structure wascompared to quantum dots emission onto a flat, thin TiO2 film. An increase in the quantum dots emission of up to 105%was in the presence of the two-dimensional photonic crystal structure. This finding is very useful for photonic deviceapplications, such as light-emitting diodes, laser systems and bio-tagging detection systems.Studi Simulasi dan Eksperimen Struktur Kristal Fotonik Dua Dimensi sebagai Pemantul Emisi Kuantum DotMasalah Arah Normal. Kristal fotonika dua dimensi tidak hanya dapat mengukung cahaya dan memandu gelombangke arah sisi horizontal, tapi juga mampu memantulkan cahaya ke arah normal dikarenakan efek moda slow Bloch .Namun bukti tentang penggunaan stuktur ini masih dibutuhkan. Untuk itu dalam penelitian ini hasil simulasi danpercobaan telah didapatkan untuk membuktikan bahwa terjadi peningkatan pantulan emisi CdSe kuantum dot colloidpada arah normal saat kristal fotonika dua dimensi digunakan. Sebuah lapisan tipis TiO2 dibentuk menjadi kristalfotonika dua dimensi denga menggunakan teknik sol-gel yang sederhana dan etching dengan menggunakanpolystyrene. Struktur ini diletakkan di atas lapisan kuantum dot CdSe. Emisi dari kuantum dot di atas kristal fotonikadua dimensi dibandingkan dengan emisi kuantum dot di atas lapisan tipis dan datar TiO2. Peningkatan emisi kuantumdot hingga mencapai 105% berkat kehadiran kristal fotonika dua dimensi. Hasil ini sangat berguna untuk aplikasidivais fotonika seperti LED, sistem laser dan sisten detesi bio-tagging."

"This research aims i) to determine the density profile and calculate the ground state energy of a quantum dot in twodimensions (2D) with a harmonic oscillator potential using orbital-free density functional theory, and ii) tounderstand the effect of the harmonic oscillator potential strength on the electron density profiles in the quantum dot.This study determines the total energy functional of the quantum dot that is a functional of the density that depends onlyon spatial variables. The total energy functional consists of three terms. The first term is the kinetic energy functional,which is the Thomas?Fermi approximation in this case. The second term is the external potential. The harmonicoscillator potential is used in this study. The last term is the electron?electron interactions described by the Coulombinteraction. The functional is formally solved to obtain the electron density as a function of spatial variables. Thisequation cannot be solved analytically, and thus a numerical method is used to determine the profile of the electrondensity. Using the electron density profiles, the ground state energy of the quantum dot in 2D can be calculated. Theground state energies obtained are 2.464, 22.26, 90.1957, 252.437, and 496.658 au for 2, 6, 12, 20, and 56 electrons,respectively. The highest electron density is localized close to the middle of the quantum dot. The density profilesdecrease with the increasing distance, and the lowest density is at the edge of the quantum dot. Generally, increasing theharmonic oscillator potential strength reduces the density profiles around the center of the quantum dot.Profil Kerapatan, Energi, dan Kuat Osilasi sebuah Kuantum Dot dalam Dua Dimensi dengan sebuah PotensialEksternal Osilator Harmonik menggunakan Fungsional Energi Bebas-orbital berdasarkan Teori Thomas?Fermi. Tujuan dari penelitian ini adalah: i) menentukan profil kerapatan dan menghitung energi keadaan dasar sebuahkuantum dot dalam dua dimensi (2D) dengan sebuah potensial osilator harmonik menggunakan teori fungsionalkerapatan bebas-orbital, dan ii) memahami efek dari kekuatan potensial osilator harmonik terhadap kerapatan elektrondalam kuantum dot. Penelitian ini menentukan fungsional energi total kuantum dot yang merupakan fungsional darikerapatan dan hanya bergantung pada variabel posisi. Fungsional energi total terdiri dari tiga suku. Suku pertama adalahfungsional energi kinetik yang dalam hal ini digunakan pendekatan Thomas?Fermi. Suku kedua adalah potensialeksternal. Dalam penelitian ini, potensial osilator harmonik yang digunakan. Suku terakhir adalah interaksi elektron?elektron yang dideskripsikan oleh interaksi Coulomb. Fungsional ini secara formal ditentukan solusinya untukmemperoleh kerapatan elektron sebagai fungsi posisi. Persamaan ini tidak dapat diselesaikan secara analitik, olehkarenanya, sebuah metode numerik digunakan untuk menentukan profil kerapatan elektron. Menggunakan profilkerapatan elektron yang diperoleh, energi keadaan dasar kuantum dot dalam 2D dapat dihitung. Nilai-nilai energikeadaan dasar yang diperoleh adalah 2,464; 22,26; 90,1957; 252,437; dan 496.658 au untuk masing-masing jumlahelektron 2, 6, 12, 20, dan 56. Kerapatan elektron tertinggi terlokalisasi pada bagian tengah kuantum dot. Profilkerapatan berkurang dengan bertambahnya jarak, dan kerapatan terendah berada pada ujung kuantum dot. Secaraumum, meningkatkan kuat osilasi akan menurunkan profil kerapatan elektron di sekitar bagian tengah kuantum dot."

"The explosive sensitivity upon the formation of supramolecular interaction between the nitro group of 3-nitro-1,2,4-triazol-5-one (NTO) and metal ions (Mn+ = Li+, Na+, Be2+ and Mg2+) has been investigated using Density FunctionalTheory at B3LYP/6-311++G** level of theory. The bond dissociation energy (BDE) of the C1?N6 trigger bond hasalso been discussed for the NTO monomer and the corresponding complexes. The interaction and bond dissociationenergy of the C6?N7 trigger bond follow the order of NTO-Be2+ > NTO-Mg2+ > NTO-Li+ > NTO-Na+ > NTOmonomer. The enhancement of the trigger bond dissociation energy in comparison with the NTO monomer correlateswell with the complex interaction energies, trigger bond length, and charge transfer. The analyses of electron densityshifts have shown that the electron density of the nitro group shifts toward the C1?N6 trigger bond upon the formationof the supramolecular interaction. As result, the trigger bond is strengthened and the sensitivity of NTO is reduced.Some of the calculated results agree with the experimental values.Sensitivitas Peledak Akibat Pembentukan Kompleks 3-Nitro-1,2,4-Triazol-5-One dan Ion Logam berdasarkanTeori Fungsional Kerapatan. Sensitivitas peledak yang terbentuk dari interaksi supramolekuler senyawa 3-nitro-1,2,4-triazol-5-one (NTO) dan ion logam (Mn+ = Li+, Na+, Be2+ and Mg2+) telah dipelajari menggunakan TeoriFungsional Kerapatan pada tingkatan teori B3LYP/6-311++G**. Energi pemutusan ikatan pada ikatan pemicu ledakan(C1-C6) juga telah dipelajari untuk monomer NTO dan senyawa kompleksnya. Energi ikat dan energi pemutusan ikatanmengikuti urutan: NTO-Be2+ > NTO-Mg2+ > NTO-Li+ > NTO-Na+ > monomer NTO. Peningkatan energi pemutusanikatan berbanding lurus dengan energi ikat, panjang ikatan pemicu ledakan dan transfer muatan. Analisis perubahankerapatan elektron menunjukkan bahwa kerapatan elektron gugus nitro berpindah pada ikatan C1-N6 ketika kompleksterbentuk. Hal ini menyebabkan ikatan pemicu ledakan menjadi semakin kuat sehingga sensitivitas NTO menjadiberkurang. Hasil kajian teoritis ini sesuai dengan hasil kajian eksperiemen."

"ABSTRAKAmmonia and phosphorus have been recognized as the cause of eutrophication in surface water. Chuat Man Canal is faced with water quality degradation problem due to the high concentrations of ammonia and total phosphorus in the water body that makes it unsuitable for fish ponds. Removal of ammonia and phosphorus by the adsorption process is simple and not requires chemical use. In addition, ammonia is well adsorbed by activated carbon and zeolite while phosphorus is adsorbed by zeolite. This research used zeolite and activated carbon for the adsorption of ammonia and total phosphorus. The results of laboratory experiments at 30 °C 200 rpm 60 minutes, revealed that adsorption of ammonia using zeolite correlated with Freundlich isotherm (R2 = 0.9031). For ammonia adsorption using activated carbon, it correlated with Langmuir (R2 = 0.9596) and Freundlich (R2 = 0.9113) isotherms, respectively. For field experiment, 9 zeolite and activated carbon adsorbent pads with ratio of 1.6:1 by weight were placed across the canal sections. Each pad had 2 openings and each opening contained its adsorbent volume of 1.0 × 0.015 × 0.6 m3 (width × length × height). The front opening contained 5 kg of activated carbon while the back part contained 8 kg of zeolite. During the study, water flow velocity at surface of water was ranged from 0.022 - 0.027 m/s. Concentration of ammonia in influent and effluent was ranged from 1.755- 8.817 mg/L and 1.473-7.063 mg/L, respectively while that for total phosphorus was ranged from 0.045 - 0.095 mg/L and 0.042 - 0.089 mg/L, respectively. The maximum removal efficiency occurred 20 and 43 minutes after installation of the adsorption pads which were 6.73% for total phosphorus and 23.17% for ammonia, respectively."