Research on Frequency Characteristics of VSG Virtual Parameter Adaptive Control Strategy Based on Fuzzy Control Theory

Traditional virtual synchronous generators (VSG) control inverters. Inverter output frequency characteristic of the virtual inertia (J) and virtual damping (D) coefficient, and the virtual parameters need to be modified and adjusted according to the purpose. To solve this problem, this paper proposes a virtual parameter adaptive control strategy based on fuzzy control theory to adjust the frequency characteristics of VSG. MATLAB/Simulink is used to build a simulation model to verify the correctness of the proposed fuzzy control theory’s adaptive virtual parameter theory.

Applications of the Hansen solubility parameter for cellulose

Based on the solubility parameter theory, the Hansen solubility parameters of various solvents were calculated and compared to predict the solubility of cellulose in various solvents, which illustrates the feasibility of Hansen solubility parameters to predict the solubility of cellulose in solvents. This paper aims to make a more accurate prediction in advance when finding suitable cellulose solvent system, and then to reduce the burden of cellulose solvent selection.

Language Change, Variation, and Universals

This volume is about how human languages get to be the way they are, why they are different from one another in some ways and not others, and why they change in the ways that they do. Given that language is a universal creation of the human mind, the puzzle is why there are different languages at all, why we don’t all speak the same language. And while there is considerable variation, there are ways in which grammars show consistent patterns. The solution to these puzzles, the author proposes, is a constructional one. Grammars consist of constructions that carry out the function of expressing universal conceptual structure. While there are in principle many different ways of accomplishing this task, the constructions that languages actually use are under pressure to reduce complexity. The result is that there is constructional change in the direction of less complexity, and grammatical patterns emerge that reflect conceptual universals. The volume consists of three parts. Part I establishes the theoretical foundations: situating universals in conceptual structure, formally defining constructions, and characterizing constructional complexity. Part II explores variation in argument structure, grammatical functions, and A′ constructions, drawing on data from a variety of languages, including English and Plains Cree. Part III looks at constructional change, focusing primarily on English and German. The study ends with some observations and speculations on parameter theory, analogy, the origins of typological patterns, and Greenbergian ‘universals’.

Comprehensive Analysis on Anomalous Phenomenon of Ethanol-Soluble PVB Membrane for Ethanol Recovery via Pervaporation

Poly(vinyl butyral) is selected as a promising ethanol-permselective membrane based the solubility parameter theory, however it exhibits anomalous water perm-selectivity in practical pervaporation process. Comprehensive analysis based on experimental and theoretical methods were carried out to explore the inherent mechanism of the anomalous performance. Firstly, sum frequency generation vibrational spectra and contact angle were developed to quantify the surface reconstruction of membrane in air and ethanol, which indicated that hydrophilic hydroxyl tended to expose on membrane surface with ethanol thus improved the membrane affinity to water. Meanwhile, swelling behaviors proved more water would accumulate in the ethanol swollen membrane. Furthermore, theoretical analysis in terms of sorption and diffusion process, based on the UNIFAC-FV model and Fujita free volume theory, confirmed the mechanism of anomalous phenomenon of poly(vinyl butyral) membrane. The comprehensive investigation was expected to provide insights into the basic separation mechanism of pervaporation process.

Non-canonical word order and temporal reference in Vietnamese

The paper revisits Duffield’s (2007) (Duffield, Nigel. 2007. Aspects of Vietnamese clausal structure: Separating tense from assertion. Linguistics 45(4). 765–814) analysis of the correlation between the position of a ‘when’-phrase and the temporal reference of a bare sentence in Vietnamese. Bare sentences in Vietnamese, based on (Smith, Carlota S. & Mary S. Erbaugh. 2005. Temporal interpretation in Mandarin Chinese. Linguistics 43(4). 713–756), are argued to obtain their temporal interpretation from their aspectual composition, and the default temporal reference: bounded events are located in the past, unbounded events at present. It is shown that the correlation so observed in when-questions is superficial, and is tied to the syntax and semantics of temporal modification and the requirement that temporal adverbials denoting future time is base generated in sentence-initial position, and past time adverbials in sentence-final position. A ‘when’-phrase, being temporally underspecified, obtains its temporal value from its base position. However, the correlation between word order and temporal reference in argument wh-questions and declaratives is factual, depending on whether the predicate-argument configuration allows for a telic interpretation or not. To be specific, it is dependent on whether the application of Generic Modification (Snyder, William. 2012. Parameter theory and motion predicates. In Violeta Demonte & Louise McNally (eds.), Telicity, change, and state. Acrosscategorial view of event structure, 279–299. Oxford: Oxford University Press) or accomplishment composition is realized. Canonical declaratives, and argument wh-questions, with telicity inducing material, license GM or accomplishment composition, yielding bounded events, hence past; by contrast, their non-canonical counterparts block GM or accomplishment composition, giving rise to unbounded event descriptions, hence non-past.

Sequential Regular Variation: Extensions of Kendall’s Theorem

Regular variation is a continuous-parameter theory; we work in a general setting, containing the existing Karamata, Bojanic–Karamata/de Haan and Beurling theories as special cases. We give sequential versions of the main theorems, that is, with sequential rather than continuous limits. This extends the main result, a theorem of Kendall’s (which builds on earlier work of Kingman and Croft), to the general setting.