45,409 research outputs found
Preparation of sub-micron PZT particles with the sol-gel technique
No full textThis paper describes the production of Pb1.0Zr0.9Ti0.1 ceramic powder, by using metal organic precursors as starting materials. In this study polyvinylpyrrolidone, PVP, was used to create a PZT–PVP sol and then also added as a secondary stage to control the particle size of the powder.
Two different sol–gel routes were used to create PZT powder. Both routes gave similar primary particle sizes in the range, 30–70 nm, but different agglomerate formations. Perovskite PZT powder was created with both routes
DIETARY CONDITIONS AND DIFFERENTIAL ACCESS TO FOOD RESOURCES AMONG THE VARIOUS CLASSES DURING THE HAN PERIOD
No full textIn this thesis, I study how food resources and dietary conditions were determined by social and economic status during the Han period in China, B.C. 206~A.D.220. Even though earlier scholars have published research concerning the Chinese food culture of this period, these studies were limited in that they only illustrated the dietary culture of the upper class or the available food resources in one geographic area. Also, without any persuasive data, it has been assumed by these earlier scholars that there were big differences in food resources and food consumption between the upper and lower classes. In this thesis, for comparison among the classes, I divide the social and economic classes into five stratified groups: nobles, officials, peasants, soldiers and convicts. After a brief introduction of the nature of each social class, I examine the food resources and nutritional condition of each group using information such as the wealth and income of each group, the market price of food resources, the agricultural products of peasants, and the amount of food distribution to soldiers and convicts. I found these data from archaeological remains, received historical records and pictorial data, and excavated texts. This research shows a broader view of Chinese dietary condition focusing not only on the variety of food resources of nobles, but also on the different food accessibilities among the officials, and the food deficiencies of peasants. It also deals with the situations of food supply for soldiers and convicts in an effort to reveal the true dietary consumption and nutritional conditions for all Chinese. This research proves that the various classes during the Han period in China had different food resources and dietary conditions
Characterizing the technological evolution of smartphones
No full textRecent technological advancements in smartphone have paved the way for the rapidly growing mobile commerce. As smartphone vendors launch the products with a rich variety of technical features for different end-user market segments, understanding the evolution of these features is of vital importance to all stakeholders in the smartphone industry. We address this issue by exploring technical specifications of smartphones at both the feature and the device level. In particular, we introduce the benchmarks to operationalize the overall performance of smartphone models, such that multidimensional technical features can be quantitatively summarized into a single index. Through the analysis of a comprehensive dataset entailing technical features for smartphone models launched during the years 2012-2015, we show that although certain features have become the standard functionality, the smartphone industry is largely innovative and continues to evolve over time. We believe our findings may provide important insights into the future development and design strategies of smartphones
Group location management for mobile subscribers on transportation systems in mobile communication networks
No full textWe propose a new location tracking scheme for subscribers on transportation systems (TSs) in which a large number of fast-moving users have the same location as the TS. The group location tracking (GLT) scheme in which a group location update is performed instead of the IS-41's individual location update has been proposed. We propose a distributed GLT (DGLT) scheme based on several virtual visitor location registers (VVLRs) and representative identities. We analyze the GLT and DGLT schemes in view of the database (DB) access cost as well as the signaling cost under one-dimensional network architecture. Compared with the IS-41 scheme, the schemes based on group management generally have a lower signaling cost and a lower DB access cost due to a significant reduction in the number of location updates. As user mobility increases or the number of users on a TS increases, the performance of the group management schemes improves. The DGLT scheme, in which a corresponding home location register selects a closest VVLR among several possible VVLRs, generally has a lower signaling cost although a DB access cost is increased slightly compared with the GLT scheme. We also obtain the regions in which the DGLT is more efficient than the IS-41 and the GLT scheme. The DGLT scheme is an appropriate solution for high signaling cost systems and the GLT scheme is useful for high DB access cost systems
Large Gain-Bandwidth Product Photomultiplication-type Organic Photodetectors Introducing Quantum Dot Layer
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Photomultiplication-type Organic Photodiodes with Fast Response Enabled by Controlling Charge Trapping Dynamics of Quantum Dot Interlayer
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Self-balanced navigation-grade capacitive microaccelerometers using branched finger electrodes and their performance for varying sense voltage and pressure
No full textThis paper presents a navigation-grade capacitive microaccelerometer, whose low-noise high-resolution detection capability is achieved by a new electrode design based on a high-amplitude anti-phase sense voltage. We reduce the mechanical noise of the microaccelerometer to the level of 5.5 mug/rootHz by increasing the proof-mass based on deep RIE process of an SOI wafer. We reduce the electrical noise as low as 0.6 mug/rootHz by using an anti-phase high-amplitude square-wave sense voltage of 19 V. The nonlinearity problem caused by the high-amplitude sense voltage is solved by a new electrode design of branched finger type. Combined use of the branched finger electrode and high-amplitude sense voltage generates self force-balancing effects, resulting in an 140% increase of the bandwidth from 726 Hz to 1734 Hz. For a fixed sense voltage of 10 V, the total noise is measured as 2.6 mug/rootHz at the air pressure of 3.9 torr, which is the 51% of the total noise of 5.1 mug/rootHz at the atmospheric pressure. From the excitation test using I g, 10 Hz sinusoidal acceleration, the signal-to-noise ratio of the fabricated microaccelerometer is measured as 105 dB, which is equivalent to the noise level of 5.7 mug/rootHz. The sensitivity and linearity of the branched finger capacitive microaccelerometer are measured as 0.638 V/g and 0.044%, respectively
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