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"The spectral intensity of direct and scattered solar radiation is of fundamental importance for various studies in civil engineering, agriculture, solar power generation, and radiation budgetestimation. In this paper, we describe a ground-based, wide-spectral-range sensor that can be used for measuring spectral intensities both in the visible and near-infrared spectral regions.The measurements are conducted either with artificial light sources ordirect/scattered solar radiation. The measured spectra yields information on the absorption features of atmosphericgases such as nitrogen dioxide (NO2), carbon dioxide (CO2) and water vapor, as well as aerosol optical properties in the atmosphere. Relatively weak absorption of nitrogen dioxide is measured with the technique of differential optical absorption spectroscopy (DOAS), whereas aerosol, carbon dioxide, and water vapor amounts are measured by matching the observed spectra with simulated ones. Both High Resolution Transmission (HITRAN) and ModerateResolution Atmospheric Transmission (MODTRAN) database/codes are used to derive column amounts of absorbing molecular species and tocharacterize aerosol optical properties. "

"The spectral intensity of direct and scattered solar radiation is of fundamental importance for various studies in civil engineering, agriculture, solar power generation, and radiation budget estimation. In this paper, we describe a ground-based, wide-spectral-range sensor that can be used for measuring spectral intensities both in the visible and near-infrared spectral regions. The measurements are conducted either with artificial light sources or direct/scattered solar radiation. The measured spectra yields information on the absorption features of atmospheric gases such as nitrogen dioxide (NO2), carbon dioxide (CO2) and water vapor, as well as aerosol optical properties in the atmosphere. Relatively weak absorption of nitrogen dioxide is measured with the technique of differential optical absorption spectroscopy (DOAS), whereas aerosol, carbon dioxide, and water vapor amounts are measured by matching the observed spectra with simulated ones. Both High Resolution Transmission (HITRAN) and Moderate Resolution Atmospheric Transmission (MODTRAN) database/codes are used to derive column amounts of absorbing molecular species and to characterize aerosol optical properties."

"ABSTRAKSifat struktur, termal, dan listrik pada temperatur tinggi dari senyawa double perovskite Sr2(Fe,Ti)O6telah dipelajari pada penelitian ini.Sr2(Fe,Ti)O6 disintesis dengan metode solid state reaction. Hasil karakterisasi x-ray diffraction pada temperatur kamar menunjukkan bahwa semua sampel memiliki fase tunggal dan memiliki struktur kristal kubik double perovskite dengan space grup pm3m. Variasi jumlah atom Fe dan Ti mengakibatkan kenaikan parameter kisi dan grainsize. Grainsize yang diperoleh berkisar antara 30 nm sampai dengan 80 nm. Sifat listrik sebagai fungsi temperatur dan frekuensi dikarakterisasi menggunakan RLC-meter dengan metode spektroskopi impedansi. Hasil karakterisasi disajikan dalam Nyquist plot dan Bode plot yang digunakan untuk mengidentifikasi rangkaian ekuivalen dan parameternya. Rangkaian ekuivalen yang diperoleh menunjukkan pengaruh grain dan grain boundary terhadap sifat material. Konduktivitas dc Sr2(Fe,Ti)O6 sebagai fungsi temperatur dijelaskan dengan menggunakan persamaan Arrhenius. Energi aktivasi yang diperoleh dari hubungan konduktivitas dc sebagai fungsi temperatur menunjukkan pengaruh grain dan grain boundary pada sampel. Hal tersebut menunjukkan kemungkinan adanya oxygen vacancy pada material Sr2(Fe,Ti)O6. Kemungkinan ini diperkuat dengan hasil karakterisasi field emission scanning electron microscopy (FESEM) untuk menggambarkan morfologi sampel

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ABSTRACTStructure, thermal, and electrical properties of double perovskite material Sr2(Fe,Ti)O6 at high temperature have been studied. Sr2(Fe,Ti)O6 was synthesized by solid state reaction method. X-ray diffraction characterization at room temperature for all samples show single phase and having cubic double perovskite structure with pm3m space group. The variation of Fe and Ti atoms result an increasing of lattice parameter and grainsize which is found between 30 nm and 80 nm. The electrical properties as a function of temperature and frequency are characterized by using RLC-meter with impedance spectroscopy method. The impedance data are presented in Nyquist and Bode plot resulting in the equivalent circuit and its parameters. The equivalent circuit shows the effect of grain and grain boundary in the electrical properties of materials. DC conductivity of Sr2(Fe,Ti)O6 as a function of temperature was explained by using Arrhenius equation. The value of the activation energy which is evaluated from dc conductivity as a function of temperature shows the effect of grain and grain boundary. The activation energy exhibits of oxygen vacancy in Sr2(Fe,Ti)O6 which is also supported by morphology of Sr2(Fe,Ti)O6 characterized by field emission scanning electron microscopy (FESEM)."