Two-dimensional tetramer-cuprate Na5RbCu4(AsO4)4Cl2: phase transitions and AFMorder as seen by 87Rb NMR

We report the Rb nuclear magnetic resonance (NMR) results in a recently synthesized Na5RbCu4(AsO4)Cl2. This complex novel two-dimensional (2D) cuprate is an unique magnetic material, which contains layers of coupled Cu4O4 tetramers. In zero applied magnetic field, it orders antiferromagnetically via a second-order low-entropy phase transition at TN = 15(1) K. We characterise the ordered state by 87Rb NMR, and suggest for it a noncollinear rather than collinear arrangement of spins. We discuss the properties of Rb nuclear site and point out the new structural phase transition(s) around 74 K and 110 K.Comment: 2 pages, 2 figures, Proceedings of SCES'05, Vienna 200

Magnetic Properties of the Novel Low-Dimensional Cuprate Na5RbCu4(AsO4)4Cl2

The magnetic properties of a new compound, Na5RbCu4(AsO4)4Cl2 are reported. The material has a layered structure comprised of square Cu4O4 tetramers. The Cu ions are divalent and the system behaves as a low-dimensional S=1/2 antiferromagnet. Spin exchange in Na5RbCu4(AsO4)4Cl2 appears to be quasi-two-dimensional and non-frustrated. Measurements of the bulk magnetic susceptibility and heat capacity are consistent with low-dimensional magnetism. The compound has an interesting, low-entropy, magnetic transition at T = 17 K.Comment: 4 pages, 5 figure

Degradasi Polietilen Tereftalat dengan Radiasi Sinar Matahari dan Metanolisis

Telah dilakukan penelitian mengenai degradasi polietilen tereftalat (PET) menjadi dibenzil tereftalat. Degradasi polietilen tereftalat (PET) pada penelitian ini didahului dengan pemanasan sampel limbah botol PET di bawah sinar matahari kemudian dilanjutkan secara metanolisisis dengan katalis seng asetat. Degradasi dengan sinar matahari dilakukan dengan cara menjemur botol plastik di bawah sinar matahari selama 0, 30, dan 60 hari. Botol plastik kemudian dipotong-potong ukuran 2x2 mm. Degradasi kemudian dilanjutkan secara metanolisisis menggunakan pelarut benzil alkohol dan seng asetat sebagai katalis. Katalis seng asetat yang digunakan divariasikan sebanyak 0; 0,3; 0,6; dan 0,9 g. Degradasi metanolisisis dilakukan secara refluks pada suhu 145-150 °C. Produk hasil degradasi dikarakterisasi titik leleh dan gugus fungsinya dengan spektrum FTIR. Hasil penelitian menunjukkan bahwa pemanasan di bawah sinar matahari selama 0, 30 dan 60 hari tidak dapat mendepolimerisasi PET yang dibuktikan dengan data titik leleh dari masing-masing sampel limbah plastik PET yang masih sama dengan rentang titik leleh PET yaitu 250-260 °C. Depolimerisasi PET dengan radiasi sinar matahari yang dilanjutkan dengan metanolisis menghasilkan produk akhir berupa dibenzil tereftalat. Adapun variasi jumlah katalis seng asetat pada tahap metanolisis tidak mempengaruhi produk akhir yang terbentuk

A Contrastive Analysis of Fi'il Madhi in Arabic and Simple Past Tense in English on the Holy Qur’an: Surah An-Naba. Gina Aprilia Kartin: 187010020

This research aims to provide a description of the simple past tense in English and Fi’il Madhi in Arabic, then analyze the similarities and differences between the past tenses of the two languages. This is intended to provide convenience in learning English and Arabic. Because according to the theory of contrastive analysis, the difference between B1 and B2 in teaching a foreign language will make it difficult for learners of one of these languages and the similarities will make it easier. This research is a literature study with a qualitative method. The data in this study are obtained from books, articles, journals and so on related to this theme. Data processing is carried out by descriptive analysis of contrastive analysis theories, simple past tense in English and fi’il madhi in Arabic. From the results of the research, several results are found, including: 1) There are four similarities of simple past tense and fi’il madhi, including: the same function, the same form, both languages can be classified into active and passive verb, and both past tense verb can change itself from the base verb. 2) There are three differences of simple past tense and fi’il madhi, including: fi’il madhi can change depending on the subject while the simple past tense does not, fi'il madhi does not have the terms regular and irregular verbs as in the simple past tense, and in fi'il madhi the verb is always placed before the subject, while in the simple past tense the verb is placed after the subject. In addition that not every fi'il madhi in Arabic has a simple past tense meaning in English. Keywords: Contrastive Analysis, Fi’il Madhi, Simple Past Tense

Sustained ventricular tachycardia in a patient with isolated non-compaction cardiomyopathy.

Isolated non-compaction of the left ventricular myocardium (INVM) was first described in 1984 as an unclassified cardiomyopathy, not being dilated, hypertrophic or restrictive. It is assumed to occur as a result of an arrest in endomyocardial morphogenesis during normal development of the heart. The disease is characterised by heart failure due to systolic and diastolic left ventricular (LV) dysfunction, systemic emboli and ventricular arrhythmias. Echocardiography has been shown to be the method of choice in diagnosis. INVM is a rare congenital cardiomyopathy and only a few cases of this condition have been reported. It is characterised by prominent and excessive trabeculation in a ventricular wall segment, with deep inter-trabecular spaces perfused from the ventricular cavity. We report a case of INVM with ventricular tachycardia induced during electrophysiological study in a 24-year-old female patient with a family history of sudden death

Sustained ventricular tachycardia in a patient with isolated non-compaction cardiomyopathy

Isolated non-compaction of the left ventricular myocardium (INVM) was first described in 1984 as an unclassified cardiomyopathy, not being dilated, hypertrophic or restrictive. It is assumed to occur as a result of an arrest in endomyocardial morphogenesis during normal development of the heart. The disease is characterised by heart failure due to systolic and diastolic left ventricular (LV) dysfunction, systemic emboli and ventricular arrhythmias. Echocardiography has been shown to be the method of choice in diagnosis. INVM is a rare congenital cardiomyopathy and only a few cases of this condition have been reported. It is characterised by prominent and excessive trabeculation in a ventricular wall segment, with deep inter-trabecular spaces perfused from the ventricular cavity. We report a case of INVM with ventricular tachycardia induced during electrophysiological study in a 24-year-old female patient with a family history of sudden death