A piezoelectric transducer‐tuned microstrip‐ring resonator oscillator operating at the second resonant mode of the ring resonator

A microstrip open‐loop resonator oscillator operating at even modes is proposed. The even mode of the ring circuit can be predicted by using a simple transmission‐line model. The new oscillator has a characteristic similar to that of a push‐push oscillator. In addition, in comparison with the push‐push oscillator, the new oscillator with one active device can minimize the size and lower the cost. A voltage‐controlled piezoelectric transducer (PET) is used to vary the resonant frequencies of the ring resonator, which in turn tunes the oscillator with a good tuning range of 4.9% at around 12.1 GHz. This tuned oscillator should have many applications in wireless systems. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

Reverse nearest neighbors in large graphs

A reverse nearest neighbor (RNN) query returns the data objects that have a query point as their nearest neighbor (NN). Although such queries have been studied quite extensively in Euclidean spaces, there is no previous work in the context of large graphs. In this paper, we provide a fundamental lemma, which can be used to prune the search space while traversing the graph in search for RNN. Based on it, we develop two RNN methods; an eager algorithm that attempts to prune network nodes as soon as they are visited and a lazy technique that prunes the search space when a data point is discovered. We study retrieval of an arbitrary number k of reverse nearest neighbors, investigate the benefits of materialization, cover several query types, and deal with cases where the queries and the data objects reside on nodes or edges of the graph. The proposed techniques are evaluated in various practical scenarios involving spatial maps, computer networks, and the DBLP coauthorship graph.     

Supercritical CO2 extraction of phthalate plasticizers from PVC

Three common phthalates, namely, dioctyl phthalate, diisodecyl phthalate, and trioctyl trimellitate, were used as plasticizers for poly(vinyl chloride) (PVC) processing, and the extraction of these plasticizers were investigated using supercritical CO₂ fluids. Factors affecting the extractions of these phthalates were focused. The molecular weight of phthalates was found to dominate the level of extraction of low temperatures, whereas the content of carbonyl groups in the phthalate was a determining factor for the level of extraction of high temperatures. Negligible extraction was observed below the critical pressure of CO₂. For 32°C, the level of the extraction is insignificant below density of ca 0.7 g/cm³, above which the level of the extraction increases roughly linearly with increasing density. For temperatures above 32°C, the density of CO₂ for apparent extractions decreased with increasing temperatures. The threshold density of CO₂ for extractions was found to be independent of the amount of a given phthalate in PVC. Two extraction rates during the extraction could be determined, with a higher rate in the first hour followed by a lower rate later in the extraction for all three phthalates. The effects of the extractions of phthalates on the flexibility of PVC were also investigated as well as the effects of the extrusion conditions, which could lead to various degrees of plasticization of PVC, on the level of extractions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4032–4037, 2003     

Über den Einfluß eines örtlich veränderlichen Reibwertes auf die Berechnung der Kräfte bei technischen Umformverfahren

Erfassung der Randschubspannung zwischen Werkzeug und Werkstück durch die Einführung eines veränderlichen Reibwertes. Abhängigkeit des Reibwertes von Druck, (Relativ-Geschwindigkeit und Temperatur aus vorliegenden physikalischen Untersuchungen der Reibverhältnisse; Reibgesetze aus Auswertung des einschlägigen Schrifttums. Vergleich verschiedener Reibgesetze bei den Umformverfahren Ziehen, Bandwalzen und Stauchen mit Hilfe der elementaren Theorie. Folgerungen für die Anwendung eines örtlich veränderlichen Reibwertes bei der Berechnung plastischer Umformvorgänge.     

Event-related potential indicators of text integration across sentence boundaries.

An event-related potentials (ERPs) study examined word-to-text integration processes across sentence boundaries. In a two-sentence passage, the accessibility of a referent for the first content word of the second sentence (the target word) was varied by the wording of the first sentence in one of the following ways: lexically (explicitly using a form of the target word); conceptually (using a paraphrase of the target word), and situationally (encouraging an inference concerning the referent of the target word). A baseline condition had no coreference between the two sentences. ERP results on the target word indicated multiple effects related to word identification and word-to-referent mapping processes. Both the explicit and paraphrase conditions, but not the inference condition, showed a reduced N400 relative to the baseline condition, consistent with immediate integration by lexico-semantic processes. A 300-ms effect (P300) was found in the paraphrase condition. The results were consistent with an immediate integration hypothesis and furthermore differentiated a lexical (N200), a conceptual (P300), and a situational (N400) component for this integration. The conceptual basis appears not to extend to predictive inferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Docosahexaenoic acid production from crude glycerol by <Emphasis Type="Italic">Schizochytrium limacinum</Emphasis> SR21

In our search for a substitute energy source, microalgal biodiesel has presented itself as a potential candidate. However, the development of biodiesel results in the overproduction of crude glycerol, which can cause undesirable environmental issues. The environmental harm can be minimized by converting crude glycerol into value-added products. One solution involves using a microalga Schizochytrium limacinum SR21 to convert crude glycerol into docosahexaenoic acid (DHA). DHA is an essential fatty acid, necessary for developing brain functions in infants and maintaining healthy brain activity in adults. In our study, the highest DHA productivity of 233.73 mg/g biomass was obtained using 3 % crude glycerol in Medium 2 at 20 °C under mixo/heterotrophic cultivation.     

Flexural properties of sawdust reinforced phenolic composites: Pilot study

The advantageous properties of sawdust and phenolic resins were combined by making sawdust reinforced phenolic composites with different percentages by weight of sawdust. The sawdust was divided into three grades in accordance with its particulate size. Garamite and propylene glycol were added individually and together to enhance the flexural properties of the composites obtained. Without any garamite and propylene glycol, it was discovered that the best flexural properties of the composites were obtained when the percentage by weight of sawdust (<300 μm) is up to 15%. Beyond this, the flexural properties dropped significantly; in addition, the fluidity of the composite was very low and the mixture was not suitable for casting. In general, the flexural modulus of the composites decreases with an increase in sawdust content, i.e., they are more elastic but their maximum flexural strain does not improve. Garamite was therefore added to improve the maximum flexural strains of the composites and this was successful. The addition of propylene glycol makes the composite more plastic. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

半导体制造商致力于解决能源效率问题

随着油价上涨与环境保护需求增长相结合的影响,能源效率已成为所有半导体公司最关心的主要问题。为了在各种不同应用中实现更高效率或更优越的能源管理产品与技术,如马达控制、电源、运算设备、消费类电子、照明设备及汽车,功率半导体成为改善燃料效率与降低排放的关键,也构成了半导体产业的新挑战。     

Price elasticity and the growth of computer spending

The price of computers is a key factor in explaining the growth of computer spending. However, it remains unclear whether the price elasticity of the demand for computers is constant over time. Findings on the pattern of price elasticity will have important implications in the study of information technology (IT) innovation diffusion. To test the hypothesis of dynamic price elasticity, we extend existing growth models to include a price factor with different elasticity specifications. Nested specifications of three growth models were tested using spending data from 1955 to 1984 adjusted by a quality price index for computers. The results indicate that three out of four competing models depict dynamic price elasticity over the investigated period. A similar pattern is also observed when the models are estimated using more recent data on mainframe computer spending. Our results underscore the dynamic behavior of price sensitivity in computer spending over time. They offer a new perspective to study innovation attributes and to examine their impacts empirically over time. Implications for information systems (IS) management and IT suppliers are also discussed     

On tree types of competitive learning algorithms with their comparisons and applications to MRI segmentation

This paper considers competitive learning networks using three types of hard, soft, and fuzzy learning schemes. The hard competitive learning algorithm is with the winner‐take‐all. The soft competition learning algorithm is with a stochastic relaxation technique using the Gibbs distribution as a dynamic neighborhood function. The fuzzy competition learning algorithm is with a fuzzy relaxation technique using fuzzy membership functions as kernel type neighborhood interaction functions. Some numerical examples are made for these three types of competitive learning schemes. The numerical results show that the fuzzy learning has better performance than hard and soft learning under the normal mixture data. We then present an application to magnetic resonance image segmentation. A real case of ophthalmology recommended by a neurologist with MR image data is examined in this paper. These competitive learning algorithms are used in segmenting the ophthalmological MRI data for reducing medical image noise effects with a learning mechanism. Based on the segmentation results, the fuzzy learning gives better performance than hard and soft learning so that the fuzzy competitive learning algorithm is recommended for use in MRI segmentation as an aid for support diagnoses. © 2010 Wiley Periodicals, Inc.