The relationship of electron Fermi energy with strong magnetic fields

In order to depict the quantization of Landau levels, we introduce Dirac $\delta$ function, and gain a concise expression for the electron Fermi energy, $E_{F}(e) \propto B^{1/4}$. The high soft X-ray luminosities of magnetars may be naturally explained by our theory.Comment: 3 pages, 1 figure, submitted to OMEG11 Proceeding (Tokyo, Japan. Nov.14-18, 2011

A Continuously Growing Dataset of Sentential Paraphrases

A major challenge in paraphrase research is the lack of parallel corpora. In this paper, we present a new method to collect large-scale sentential paraphrases from Twitter by linking tweets through shared URLs. The main advantage of our method is its simplicity, as it gets rid of the classifier or human in the loop needed to select data before annotation and subsequent application of paraphrase identification algorithms in the previous work. We present the largest human-labeled paraphrase corpus to date of 51,524 sentence pairs and the first cross-domain benchmarking for automatic paraphrase identification. In addition, we show that more than 30,000 new sentential paraphrases can be easily and continuously captured every month at ~70% precision, and demonstrate their utility for downstream NLP tasks through phrasal paraphrase extraction. We make our code and data freely available.Comment: 11 pages, accepted to EMNLP 201

Preparation, Characterization and Reactivities of Early Transition Metal Silyl Compounds

This dissertation focuses on syntheses, characterization and reactivities of Groups 4 and 5 metal amide silyl complexes free of anionic π-ligands. A summary of the research in this dissertation is provided in Chapter 1. Chapter 2 reports an unusual reaction between Ta(NMe2)4SiButPh2 (1) and O2. Three products (Me2N)4Ta(OSiButPh2) (2), (Me2N)3Ta(ONMe2)(OSiButPh2) (3) and (Me2N)2(Ph2ButSiO)2(Me2NCH2NMe)2Ta2(μ-O)2 (4) were isolated from the reaction. Preparation and characterization of Hf and Ta disilyl complexes are presented in Chapter 3. Novel exchange processes of Zr and Hf amides with silyl ligands were are described in this Chapter. Chapter 4 describes the kinetics studies of complex (Me2N)3Ta[Si(SiMe3)3]2 (11) complexes with LiSiButPh2 (7). The reaction mechanism was found to follow a dissociative pathway. Tetrahydrofuran (THF) was found to promote the substitution. Chapter 5 reports the studies of the thermal decomposition of (Me2N)3Ta(SiButPh2)2 (15) and (Me2N)3Ta(SiButPh2)[Si(SiMe3)3] (16). First-order kinetics was observed and the activation parameters ΔH≠, ΔS≠, and ΔG≠ 298 K for the reaction have been obtained. Heating the mixture of W(CH2SiMe3)3(≡CSiMe3)(PMe2Ph) (18a) and its bis(alkylidene) tautomer W(CH2SiMe3)2(=CHSiMe3)2(PMe2Ph) (18b) in the presence of excess PMe2Ph leads to the formation of W(CH2SiMe3)(=CHSiMe3)(≡CSiMe3)(PMe2Ph)2 (19). The reaction process was found to follow first-order kinetics, and the rate constant is independent of the concentrations of PMe2Ph. A possible mechanistic pathway is discussed