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Ionic Liquids In Analytical Chemistry, Jared L. Anderson, Daniel W. Armstrong, Guor-Tzo Wei
Ionic Liquids In Analytical Chemistry, Jared L. Anderson, Daniel W. Armstrong, Guor-Tzo Wei
Jared L. Anderson
Room-temperature ionic liquids (RTILs), also known as liquid organic, molten, or fused salts, are a class of nonmolecular ionic solvents with low melting points. The accepted definition of an RTIL is any salt that has a melting point lower than ambient temperature (1). However, “ionic liquid” (IL) is often applied to any compound that has a melting point <100 °C. Most common RTILs are composed of unsymmetrically substituted nitrogen-containing cations (e.g., imidazole, pyrrolidine, pyridine) with inorganic anions (e.g., Cl–, PF6 –, BF4 –). ILs are also interesting because of their other useful and intriguing physicochemical properties. Wilkes et al. first reported ambient-temperature ILs based on the 1-alkyl-3-methylimidazolium cation in 1982 (2). Since then, many ILs containing a variety of cations and anions of different sizes have been synthesized to provide specific characteristics.
Nonparametric Event Study Tests, Arnold R. Cowan
Nonparametric Event Study Tests, Arnold R. Cowan
Arnold R. Cowan
This paper provides the first documentation of the power and specification of the generalized sign test, which is based on the percentage of positive abnormal returns in an estimation period. In simulations using daily stock return data, the generalized sign test is well specified with both exchange listed and Nasdaq stocks. A rank test is more powerful under ideal conditions. However, the rank test is more sensitive to increases in the length of the event window, to increases in return variance and to thin trading. The generalized sign test is a viable alternative to the rank test under these conditions.