1,631 research outputs found

    China’s Electricity Market Reform and Power Plants Efficiency

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    In the past three decades, Chinese electricity industry has experienced a series of regulatory reforms serving different purposes at different stages. In 2002, the former vertically integrated electricity utility - the State Power Corporation (SPC) – was divested and the generation sector was separated from the transmission and distribution networks in an effort to improve production efficiency. In this paper we study the impact of the reform on efficiency of fossil-fired power plants using plant-level data during 2000-2008. Our results from the data envelopment analysis (DEA) and panel regressions show that: 1) the total factor productivity (TFP) growth mainly comes from technological change; 2) the technical efficiency of previously SPC-managed power plants is converging to that of better-performing independent power producers (IPPs); 3) capacity utilization and unit size are significant factors affecting changes in technical efficiency and the pattern of converging technical efficiency between the two kinds of power plants; 4) most plants operate at increasing returns to scale indicating further cost savings could be achieved through increasing output.Efficiency, DEA, Malmquist Index, China, Electricity, Industrial Organization, Productivity Analysis, Resource /Energy Economics and Policy, D24, L11, L51, L94, L98,

    In situ Transmission Electron Microscopy Study on the Phase Transitionsin Lead-Free (1−x)(Bi1/2Na1/2)TiO3–xBaTiO3 Ceramics

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    The phase transitions in unpoled lead-free (1−x)(Bi1/2Na1/2)TiO3–xBaTiO3 (x = 0.06 and 0.11) ceramics are investigated using hot-stage transmission electron microscopy (TEM). It is found that large ferroelectric domains in both ceramics start to disappear around Td, the depolarization temperature. After the transition, both compositions exhibit the P4bm tetragonal symmetry in the form of nanodomains. The structural transition observed by the in situTEM experiments seems to be gradual and occurs within a temperature range of several tens of degrees, in contrast to the sharp anomaly at Td revealed by the dielectric characterization. With further increasing temperature, no structural change was observed for both compositions across TRE, where the dielectric frequency dispersion vanishes, and Tm, where the dielectric permittivity reaches maximum. The tetragonal-to-cubic transition is diffuse and takes place in a broad temperature window well above both TRE and Tm. These results of structural phase transitions are summarized in a phase diagram with its composition range covering the morphotropic phase boundary (MPB)

    Morphotropic phase boundary and electrical properties of lead-free (1−x)BaTiO3−xBi(Li1/3Ti2/3)O3 ceramics

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    Dense polycrystalline ceramics of lead-free perovskitesolid solution(1−x)BaTiO3−xBi(Li1/3Ti2/3)O3 (0.05≤x≤0.20) have been synthesized via the conventional solid state reaction method. A morphotropic phase boundary separating the tetragonal and orthorhombic phases was observed between the compositions x=0.07 and 0.10. With increasing Bi(Li1/3Ti2/3)O3 content, the solid solution displays a stronger frequency dispersion in its dielectric behavior and a significant suppression in the sharp dielectric anomaly at the Curie point as well as the remanent polarization. However, the Curie point of the solid solution is almost independent of x in the composition range studied. These behaviors can be explained by the observed core-shell grain structure. The incorporation of Bi(Li1/3Ti2/3)O3 into BaTiO3 leads to the formation of nanodomains in the shell, which imparts the relaxor characteristics to the dielectric behavior. The core of the grain preserves the large lamellar domains as those in BaTiO3, contributing to the sharp transition at ∼130 °C. The best piezoelectric coefficient was obtained in the composition x=0.07 with d33=110 pC/N

    Differential effects of script system acquisition and social immersion experience on face perception

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    Informelle Berichte zeigten größere Amplituden der durch Gesichter ausgelösten N170 Komponente im Ereigniskorrelierten Potenzial (EKP) bei asiatischen als bei kaukasischen Probanden. Als mögliche Ursache vermutete ich unterschiedliche Erfahrungen mit logographischen bzw. alphabetischen Schriftsystemen (Schriftsystem-Hypothese) oder die verstärkte Exposition mit unbekannten Gesichtern während der Immersion in eine neue soziale oder ethnische Umgebung (soziale Immersions-Hypothese). Zur Überprüfung dieser Hypothesen führte ich zwei kulturvergleichende Studien mit Erwachsenen bzw. Kindern durch. In Studie 1 untersuchte ich einheimische Chinesen und nicht-chinesische Auswärtige in Hongkong und deutsche Einheimische und chinesische Auswärtige in Berlin. Die Auswärtigen an beiden Orten zeigten größere N170 Amplituden auf Gesichter als die Einheimischen. Außerdem zeigten Deutsche, die erst kurze Zeit in Berlin lebten ähnliche Amplituden wie langjährige Einheimische. Insgesamt unterstützt Studie 1 die soziale Immersions-Hypothese, dass die Immersion in eine neue ethnische Umgebung zu einer Vergrößerung der N170 führt. Studie 2 untersuchte die Schriftsystem-Hypothese bei chinesischen und deutschen Erstlesern am Ende der ersten oder zu Beginn des zweiten Schuljahres an ihrem jeweiligen Heimatort. Die Ergebnisse unterstützen die Schriftsystem-Hypothese, dass chinesische Kinder eine größere N170 auf Gesichter zeigen als deutsche. Insgesamt konnte die vorliegende Dissertation zwei neue Einfluss-Faktoren auf das Gesichterverarbeitungs-System nachweisen, das erworbene Schriftsystem (logographische versus alphabetisch) und die Erfahrung sozialer Immersion in eine neue ethnische Umgebung. Diese Effekte zu ganz unterschiedlichen Zeitpunkten der Entwicklung (Kindheit vs. junges Erwachsenen-Alter) zeigen, dass das Gesichterverarbeitungs-System über lange Zeit seine Plastizität behält.Informal reports have shown larger face-elicited N170 component of event-related potential (ERP) in Asians than Caucasians participants. I proposed that different experience with logographic versus alphabetic scripts (script system hypothesis) or by exposure to abundant novel faces during the immersion into a new social and/or ethnic environment (social immersion hypothesis) as a possible cause. To test these hypotheses, I conducted two cross-cultural ERP studies with adults and Children. In Study 1, I examined Chinese locals and non-Chinese foreigners in Hongkong, and German locals and Chinese foreigners in Berlin. It turned out that the foreigners in both locations showed larger N170 amplitudes to faces than the locals. In addition, Germans who had only lived in Berlin for a short time showed similar face N170 amplitudes as long-term Berlin residents. In sum, Study 1 supports the social immersion hypothesis that immersing into a new ethnic environment drives an increase of face N170. Study 2 investigated the scripts system hypothesis in Chinese and German early readers assessed at the end of the first-grade or at the beginning of the second grade in their respective home towns. The findings support the script system hypothesis that Chinese children showed larger face N170 amplitudes than German children. Overall, the present thesis demonstrated two new influencing factors on the face processing system, the acquired script system (logographic vs. alphabetic) and the social immersion experience in a new ethnic environment. More specifically, learning to read a visually complex logographic Chinese script or immersing into an other-ethnic social environment facilitates early perceptual processing of faces. These effects acquired at different stages of development (early childhood versus young adulthood) show that the face processing system retains its plasticity over a long period of time

    Using X+V to construct a non-proprietary speech browser for a public-domain SpeechWeb

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    A SpeechWeb is a collection of hyperlinked speech applications that are distributed over the Internet. Users access the speech applications through remote browsers, which accept human-voice-input and return synthesized-voice-output. In previous research, a new architecture (LRRP) has been proposed, which is ideally suited for building a Public-Domain SpeechWeb. However, a non-proprietary speech browser is needed for this architecture. In this thesis, we have solved several limitations of X+V, a programming language for developing Multimodal applications, and we have used X+V to build a viable Public-Domain SpeechWeb browser. Our browser has the following properties: real-time human-machine speech interaction; ease of installation and use; acceptable speech-recognition accuracy in a suitable environment; no cost, non-proprietary, ease of distribution; use of common communication protocol---CGI; ease of creation of speech applications; possibility to deploy on mobile devices.Dept. of Computer Science. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2006 .M31. Source: Masters Abstracts International, Volume: 45-01, page: 0360. Thesis (M.Sc.)--University of Windsor (Canada), 2006

    Residential Energy Consumption in Urban China

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    Residential energy consumption (REC) is the second largest energy use category (10%) in China and urban residents account for most of the REC. Understanding the underlying drivers of variations of urban REC thus helps to identify challenges and opportunities and provide advices for future policy measures. This paper applies the logarithmic mean Divisia index (LMDI) to a decomposition of China’s urban REC during the period of 1998-2007 at disaggregated product/activity level using data collected from a wide range of sources. Our results have shown an extensive structure change towards a more energy-intensive household consumption structure as well as an intensive structure change towards high-quality and cleaner energy such as electricity, oil, and natural gas, which reflects a changing life style and consumption mode in pursuit of a higher level of comfort, convenience and environmental protection. We have also found that China’s price reforms in the energy sector have contributed to a reduction of REC while scale factors including increased urban population and income levels have played a key role in the rapid growth of REC. We suggest that further deregulation in energy prices and regulatory as well as voluntary energy efficiency and conservation policies in the residential sector should be promoted.Residential Energy Consumption, Index Decomposition Analysis (IDA), China, Consumer/Household Economics, Resource /Energy Economics and Policy, Q32, Q43,

    Phase diagram of unpoled lead-free (1-x)(Bi1/2Na1/2)TiO3–xBaTiO3 ceramics

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    A phase diagram for unpoled ceramics in the lead-free (1−x)(Bi1/2Na1/2)TiO3–xBaTiO3 binary system is constructed for the first time based on transmission electron microscopy (TEM) and dielectric study. In contrast to the reported phase diagram determined using poled ceramics, an additional phase region exhibiting P4bm nanodomains was revealed. A new concept “relaxor antiferroelectric” was proposed to describe the unique short-range antiferroelectric order of this phase. The results suggest that electric field-induced phase transitions must be taken into consideration in optimizing the piezoelectric properties in these lead-free ceramics
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