Control and Limit Enforcements for VSC Multi-Terminal HVDC in Newton Power Flow

This paper proposes a novel method to automatically enforce controls and limits for Voltage Source Converter (VSC) based multi-terminal HVDC in the Newton power flow iteration process. A general VSC MT-HVDC model with primary PQ or PV control and secondary voltage control is formulated. Both the dependent and independent variables are included in the propose formulation so that the algebraic variables of the VSC MT-HVDC are adjusted simultaneously. The proposed method also maintains the number of equations and the dimension of the Jacobian matrix unchanged so that, when a limit is reached and a control is released, the Jacobian needs no re-factorization. Simulations on the IEEE 14-bus and Polish 9241-bus systems are performed to demonstrate the effectiveness of the method.Comment: IEEE PES General Meeting 201

Modeling the hard states of three black hole candidates

Simultaneous multiwavelength observations were recently performed for three black hole candidates --- SWIFT J1753.5-0127, GRO J1655-40 and XTE J1720-318. In this paper we test the accretion-jet model originally proposed to XTE J1118+480 by investigating the hard state of these three sources using this model. The accretion flow in the model is composed of an inner hot accretion flow and an outer truncated thin disk. We find that the model satisfactorily explains the spectrum ranging from radio to X-rays, with the radio and X-ray spectra dominated by the synchrotron and thermal Comptonization emissions in the jet and the hot accretion flow respectively, while the infrared and optical being the sum of the emissions from the jet, hot accretion flow, and the truncated thin disk. Similar to the case of XTE J1118+480, the model can also explain, although only qualitatively in some cases, the observed timing features including QPO, and positive and negative time lags between the optical and X-ray emissions detected in SWIFT J1753.5-0127. The origin of the ejection events detected in XTE J1720-318 is also briefly discussed.Comment: 7 pages, 6 figures accepted for publication in ApJ, minor modification after proo

Preparation, Characterization, and Applications of Carbonaceous Mesophase: A Review

Carbonaceous mesophase with a nematic liquid crystal structure possesses an easily graphitizable characteristic and can be used as a promising raw material to prepare anisotropic carbon and graphite materials with high performance and multifunction. Therefore, the carbonaceous mesophase occupies a pivotal and irreplaceable position in many frontier and cutting-edge fields. The controllable preparation and characterization of carbonaceous mesophase derived from a model molecule (i.e., naphthalene) are presented, especially the formation, development, and transformation of anisotropic liquid crystalline mesophase in the synthetic naphthalene pitch during the process of liquid-phase carbonization (350–450°C). The increasing applications of naphthalene-based carbonaceous mesophase as an ideal precursor material for fabricating representative advanced carbon materials with high added value (e.g., mesophase pitch-derived coke, mesocarbon microbeads, mesophase pitch-based carbon foam, high-modulus mesophase pitch-based carbon fibers, and high-thermal-conductivity carbon-based composites, etc.) are reviewed in detail in this chapter

Acculturation and Social Competence of Chinese Students Studying Abroad: A Comprehensive Perspective

The research examines the acculturation of Chinese students studying abroad from a social competence perspective. The author developed a new concept “Cross-cultural socialization panic” to better understand and analyze the socializing problems that students meet in the process of acculturation. Drawing on 6 in-depth interviews, the article examines students’ level of acculturation from three aspects: Cross-cultural living experiences, cultural richness, and academic social ability. The article finds that it is common for students to have difficulty socializing well with foreign students. What’s more, the composition of an international student’s social circle depends largely on the number of Chinese people they have access to, as Chinese people have a strong sense of cultural identity and collectivism that prevents them from interacting with the local culture. However, when Chinese students engage in academic exchanges with professors, the more successful ones are generally purposeful and methodical. Theoretically, the article further discusses the application of this finding both theoretically and practically. This research can lead to a deeper exploration of both acculturation and social competence, as well as guidance for acculturation education in schools and students themselves