High-resolution temperature-dependent Brillouin scattering studies of ferroelectric K3Nb3O6(BO3)2

High-resolution micro-Brillouin scattering studies of K3Nb3O6(BO3)2, exhibiting superionic and ferroelectric properties, were performed in the temperature range of 300–870 K. Strong increase in damping of longitudinal and transverse acoustic phonons corresponding to the c33 and c44 elastic constants was observed above 650 K. This increase in damping was correlated with anomalous decrease in the c33 and c44 elastic constants and strong increase in central peak intensities. The observed behavior has been attributed to melting of the K+ sublattice as a result of the order-disorder phase transitions. The obtained results also revealed a critical slowing down of the E[double-prime]-symmetry relaxation mode near the phase transitions at 388 and 690 K as well as the broad A1[prime]-symmetry relaxation mode near the phase transition at 750 K. This behavior indicates that the relaxation modes play an important role in the mechanism of these phase transitions. In particular, this behavior suggests that the phase transition near 690 K is induced by instability of the E[double-prime]-symmetry relaxation mode

ANALISIS STRATEGI PREVENTIF POLIS LAPSE AKIBAT KETERLAMBATAN DALAM PEMBAYARAN PREMI LANJUTAN (Studi Di BNI Life Insurance Divisi Syari’ah Bandar Lampung)

ABSTRAK Asuransi di Indonesia bukanlah suatu hal yang baru untuk kehidupan berekonomi dalam masyarakat. Sebagian masyarakat mengambil langkah untuk mengikuti asuransi karena tingginya kesadaran perlindungan risiko. Asuransi syariah adalah asuransi yang sumber hukum, akad, jaminan (risiko), investasi, pengelolaan dana, kepemilikan dan lainnya berdasarkan nilai dan prinsip-prinsip syariah. Sedangkan polis lapse adalah keadaan penghentian penanggungan asuransi akibat tidak dibayarkannya premi. Tidak dibayarkannya premi bisa disebabkan oleh kelalaian nasabah seperti lupa saat jatuh tempo, karna kesibukan pekerjaan, dan lain sebagainya sehingga berakibat polis lapse. Untuk itu diperlukan strategi-strategi preventif guna mencegah terjadinya polis lapse akibat keterlambatan dalam pembayaran premi. Penelitian ini untuk mengetahui strategi preventif polis lapse BNI Life Insurance divisi syariah Bandar Lampung dalam mencegah terjadinya risiko polis lapse serta bagaimana strategi preventif polis lapse dalam perspektif ekonomi islam. Tujuan penelitian ini adalah untuk mengetahui strategi preventif yang diterpakan BNI Life Insurance divisi syariah Bandar Lampung dalam mencegah polis lapse, dan untuk mengetahui strategi preventif polis lapse dalam perspektif ekonmi islam. Metode penelitian ini merupakan penelitian lapangan (field research), yang bersifat deskriptif dengan pendekatan kualitatif. Sumber data yang digunakan yaitu data primer dan data sekunder. Metode pengumpulan data melalui observasi, wawancara, dan dokumentasi. Pengelolahan datanya dilakukan melalui editing, reconstructing dan sistematizing. Berdasarkan hasil penelitian BNI Life Insurance divisi syariah Bandar Lampung strategi preventif polis lapse yang diterapkan yaitu berupa sistem pembayaran auto debet, mengadakan metode pembayaran yang fleksibel, menghindari miss selling dengan cara memberikan pelatihan yang matang kepada agency, dan adanya reminder atau pengingat kepada nasabah. Penerapan strategistrategi tersebut adalah suatu bentuk menajemen risiko Dalam persepektif ekonomi islam manajemen risko adalah suatu amanah, sesuai dengan firman Allah swt. pada Q.S. Luqman (31) ayat 34 Keberhasilan dalam melakukan pengelolaan risiko dapat mendatangkan maslahat yang lebih baik. Dengan timbulnya kemaslahatan tersebut, bisa dimaknai sebagai suatu keberhasilan umat manusia dalam menjaga amanah dari Allah swt. Kata kunci : Strategi Preventif, Polis Lapse, Prem

Heat capacity, Raman, and Brillouin scattering studies of M2O–MgO–WO3–P2O5 glasses (M=K,Rb)

The authors report the results of temperature-dependent Brillouin scattering from both transverse and longitudinal acoustic waves, heat capacity studies as well as room temperature Raman scattering studies on M2O–MgO–WO3–P2O5 glasses (M=K,Rb). These results were used to obtain information about structure and various properties of the studied glasses such as fragility, elastic moduli, ratio of photoelastic constants, and elastic anharmonicity. They have found that both glasses have similar properties but replacement of K+ ions by Rb+ ions in the glass network leads to decrease of elastic parameters and P44 photoelastic constant due to increase of fragility. Based on Brillouin spectroscopy they show that a linear correlation between longitudinal and shear elastic moduli holds over a large temperature range. This result supports the literature data that the Cauchy-type relation represents a general rule for amorphous solids. An analysis of the Boson peak revealed that the form of the frequency distribution of the excess density of states is in agreement with the Euclidean random matrix theory. The reason of the observed shift of the maximum frequency of the Boson peak when K+ ions are substituted for Rb+ ions is also briefly discussed

Temperature-dependent studies of the geometrically frustrated pyrochlores Ho2Ti2O7 and Dy2Ti2O7

A temperature-dependent Raman study of Ho2Ti2O7 and Dy2Ti2O7 single crystals was performed in the 5–873 K temperature range. Polarized spectra allowed us to establish the symmetries of the observed bands and revise the mode assignment made in previous works. Our studies revealed also two additional bands near 287 and 300 cm−1 for Dy2Ti2O7, which can be assigned to crystal field transitions in Dy3+ ions. Temperature dependent Raman studies showed large increase of linewidths. These changes have been analyzed in terms of strong third-order phonon-phonon anharmonic interactions. The Raman spectra also showed anomalous softening of the majority of phonon modes upon cooling in the whole temperature range studied. In contrast to this behavior, the F2g 310 cm−1 and Eg 330 cm−1 phonon modes showed hardening upon cooling down to about 100–120 K and then anomalous softening below this temperature. This anomalous behavior of phonon wave numbers has been attributed to the increase in octahedral distortion upon cooling