The Korean I-suffix: A functional approach

This dissertation treats a problem presented by Korean syntax. The suffix $\{-i\},$ realized variously as -i, -hi, -li, -ki, may be used to express (among others) prototypical passives, middle voice, and causatives. I attempt to provide an answer to the question "How are these uses related?' The semantic/conceptual configuration of an event is projected as an asymmetrical relation between the sentence initial and sentence middle positions. Sentence initial position is assigned a special semantic property, which I call EMPOWEREDNESS. The requirements of EMPOWEREDNESS can be met by a less than optimal participant (i.e., creating a mismatch between the semantics of the position and its filler) as long as the I-suffix is present on the verb. The I-suffix reduces the EMPOWEREDNESS of the sentence-initial position. This reduction alters the relation between sentence initial position and the participant filler and may achieve either 'passive' or 'causative' effects. The so-called 'passive' emerges as a cluster of related constructions, which signify the reduced EMPOWEREDNESS of the sentence initial position. In 'causative' constructions, I-suffix projects decreased EMPOWEREDNESS to sentence initial position by removing some semantic portion from the sentence initial position, transferring it to the second position. Thus, the semantic character of the event--the role properties it projects upon the sentence initial participant--provides the matrix for the I-suffix. The effect of the I-suffix varies widely in different events, even while the suffix accomplishes a common function across all these environments

Achieving volatile potassium promoted ammonia synthesis via mechanochemistry

Potassium oxide is used as a promotor in industrial ammonia synthesis, although metallic potassium is better in theory. Here, the authors demonstrate metallic potassium, an unstable metal that easily volatilizes at high temperature, can be used as a promotor for ammonia synthesis. Potassium oxide (K2O) is used as a promotor in industrial ammonia synthesis, although metallic potassium (K) is better in theory. The reason K2O is used is because metallic K, which volatilizes around 400 degrees C, separates from the catalyst in the harsh ammonia synthesis conditions of the Haber-Bosch process. To maximize the efficiency of ammonia synthesis, using metallic K with low temperature reaction below 400 degrees C is prerequisite. Here, we synthesize ammonia using metallic K and Fe as a catalyst via mechanochemical process near ambient conditions (45 degrees C, 1 bar). The final ammonia concentration reaches as high as 94.5 vol%, which was extraordinarily higher than that of the Haber-Bosch process (25.0 vol%, 450 degrees C, 200 bar) and our previous work (82.5 vol%, 45 degrees C, 1 bar)

Extreme Enhancement of Carbon Hydrogasification via Mechanochemistry

Carbon hydrogasification is the slowest reaction among all carbon-involved small-molecule transformations. Here, we demonstrate a mechanochemical method that results in both a faster reaction rate and a new synthesis route. The reaction rate was dramatically enhanced by up to 4 orders of magnitude compared to the traditional thermal method. Simultaneously, the reaction exhibited very high selectivity (99.8 % CH4, versus 80 % under thermal conditions) with a cobalt catalyst. Our study demonstrated that this extreme increase in reaction rate originates from the continuous activation of reactive carbon species via mechanochemistry. The high selectivity is intimately related to the activation at low temperature, at which higher hydrocarbons are difficult to form. This work is expected to advance studies of carbon hydrogasification, and other solid-gas reactions.clos

Large-Scale Synthesis of Ultrathin Manganese Oxide Nanoplates and Their Applications to T1 MRI Contrast Agents

Lamellar structured ultrathin manganese oxide nanoplates have been synthesized from thermal decomposition of manganese(II) acetylacetonate in the presence of 2,3-dihydroxynaphthalene, which promoted two-dimensional (2-D) growth by acting not only as a strongly binding surfactant but also as a structure-directing agent. Ultrathin manganese oxide nanoplates with a thickness of about 1 rim were assembled into a lamellar structure, and the width of the nanoplates could be controlled from 8 to 70 nm by using various coordinating solvents. X-ray absorption near-edge structure (XANES) spectra at the Mn K edge clearly showed that the nanoplates are mainly composed of Mn(II) species with octahedral symmetry. These hydrophobic manganese oxide nanoplates were ligand-exchanged with amine-terminated poly(ethyleneglycol) to generate water-dispersible nanoplates and applied to T1 contrast agents for magnetic resonance imaging (MRI). They exhibited a very high longitudinal relaxivity (r(1)) value of up to 5.5 mM(-1)s(-1) derived from their high concentration of manganese ions exposed on the surface, and strong contrast enhancement of in vitro and in vivo MR images was observed with a very low dose.close1