40纳米500MHz DSP核心的时钟设计与分析

在低于40纳米的超深亚微米VLSI设计中,时钟树网络在电路时序收敛、功耗、PVT变异容差和串扰噪声规避方面所起的作用要更重要得多。     

采用微捷码工具处理65纳米设计时序收敛问题(上)

65纳米设计时序收敛问题介绍时序收敛一直是当代ASIC设计物理实现的主要问题,特别是对于那些用于通信产品中的ASIC来说更是如此。我们有一项65纳米ASIC就是这种设计。它拥有2400万门数和4400万内存位,大部分逻辑将一直以400MHz     

Isocyanates,aminoisocyanates and amines from fires—a screening of common materials found in buildings

Isocyanates, aminoisocyanates and amines were quantified from the combustion of 24 different materials or products typically found in buildings. Small‐scale combustion experiments were conducted in the cone calorimeter, where generally well‐ventilated combustion conditions are attained. Measurements were further made in two different full‐scale experiments. Isocyanates and amino‐compounds were sampled using an impinger‐filter sampling system with a reagent solution of di‐n‐butylamine in toluene. Filter and impinger solution were analysed separately using LC‐MS technique. Further the particulate distribution in the smoke gases was determined by impactor technique, and selected gaseous compounds quantified by FTIR. It was found in the small‐scale that isocyanates were produced from the majority of the materials tested. The highest concentration was found for glass wool insulation, and further high concentrations were found for PUR products, particleboard, nitrile rubber and melamine. Lower concentrations were found for wood and cable‐products. Amino‐isocyanates and amines were generally found from PUR products only. The distribution of isocyanates between the particulate‐ and fluid phases varied for the different materials and a tendency to enrichment of particles was seen for some of the materials. Further, when comparing the potential health hazard between isocyanates and other major fire gases (based on NIOSH IDLH‐values) it was found that isocyanates in several cases represented the greatest hazard. Copyright © 2003 John Wiley & Sons, Ltd.     

Trend reversal of nitrate in Danish groundwater--a reflection of agricultural practices and nitrogen surpluses since 1950

This paper assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. First, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis of distribution, trends, and trend reversals in the groundwater nitrate concentration. Second, knowledge about the N surplus in Danish agriculture since 1950 is used as an indicator of the potential loss of N. Third, groundwater recharge CFC (chlorofluorocarbon) age determination allows linking of the first two data sets. The development in the nitrate concentration of oxic groundwater clearly mirrors the development in the national agricultural N surplus, and a corresponding trend reversal is found in groundwater. Regulation and technical improvements in the intensive farming in Denmark have succeeded in decreasing the N surplus by 40% since the mid 1980s, while at the same time maintaining crop yields and increasing the animal production of especially pigs. Trend analyses prove that the youngest (0-15 years old) oxic groundwater shows more pronounced significant downward nitrate trends (44%) than the oldest (25-50 years old) oxic groundwater (9%). This amounts to clear evidence of the effect of reduced nitrate leaching on groundwater nitrate concentrations in Denmark.     

Trace ratio criterion based generalized discriminative learning for semi-supervised dimensionality reduction

Dealing with high-dimensional data has always been a major problem in many pattern recognition and machine learning applications. Trace ratio criterion is a criterion that can be applicable to many dimensionality reduction methods as it directly reflects Euclidean distance between data points of within or between classes. In this paper, we analyze the trace ratio problem and propose a new efficient algorithm to find the optimal solution. Based on the proposed algorithm, we are able to derive an orthogonal constrained semi-supervised learning framework. The new algorithm incorporates unlabeled data into training procedure so that it is able to preserve the discriminative structure as well as geometrical structure embedded in the original dataset. Under such a framework, many existing semi-supervised dimensionality reduction methods such as SDA, Lap-LDA, SSDR, SSMMC, can be improved using our proposed framework, which can also be used to formulate a corresponding kernel framework for handling nonlinear problems. Theoretical analysis indicates that there are certain relationships between linear and nonlinear methods. Finally, extensive simulations on synthetic dataset and real world dataset are presented to show the effectiveness of our algorithms. The results demonstrate that our proposed algorithm can achieve great superiority to other state-of-art algorithms.     

Influence of Loss Model on Design Discharge of Homogeneous Plane

By applying the kinematic wave method to a homogeneous, rectangular overland plane, the influence of the constant and proportional-loss models on the design discharge are examined. The examination shows that with the use of the proportional-loss model, there is no partial-area effect and the design discharge is governed by the full-area contribution. On the other hand, with the use of the constant-loss model, there is no partial-area effect if the loss rate is small. For larger loss rates, there is a partial-area effect; and for this case, the design is complicated, since there is a need to search for the critical storm that governs the partial-area effect. The characteristic of the critical storm is that its rate of decrease in rainfall intensity with duration equals the corresponding rate of increase in the contributing area. The preceding findings are consistent with the design concept in the rational method that uses the proportional-loss model, and the results from earlier studies that used the constant-loss model.     

Proton magnetic resonance imaging of lipid in pecan embryos

Magnetic resonance images of plant tissues typically are manifestations of water protons in tissues. Within oilseeds, however, lipids contain a major portion of the mobile protons, which should enable specific imaging of lipids. In this study, experiments were done to demonstrate spin-echo imaging (SEI) and chemical-shift imaging (CSI) of lipid within nonimbibed and imbibed embryos of pecan (Carya illinoensis), a high-lipid seed. Magnetic resonance spectra of airdry embryos contained a single major peak for lipid, whereas those of imbibed embryos contained separate peaks for water and lipid. This separation of spectral peaks enabled CSI of distributions of either lipids or water in imbibed embryos. A longer spin-spin relaxation time of lipid protons than of water protons in imbibed embryos allowed selective SEI of lipids in those embryos. SEI of normal, dry embryos revealed fairly uniform distribution of lipids across tissues. Similar images of embryos damaged by the fungusPhoma exocarpina or the insectZerara viridula were less intense than those of a normal embryo, reflecting the lower oil contents of the damaged embryos. Magnetic resonance imaging should provide a useful technology for studying lipid distribution and metabolism within oil seeds.     

The Dynamics of Indonesia's Urbanisation, 1980-2006

This study examines continuity and change in patterns of Indonesia's urbanisation during the boom economy until the decentralisation era, using data mainly from the National Population Census 1980-2000 and from the Village Potential (PODES) 2006. Urbanisation in Indonesia is still characterised by a heavy concentration of the urban population in a few large cities, notably the Jakarta Metropolitan Area (JMA), which might reflect an integration of Jakarta into the global economy. It might also reflect an interurban disparity, between large and smaller cities. The population on the fringes of large cities is growing rapidly, while in the inner cities it is increasing at a very low rate of growth. Urban spatial development in Java is shaping belts, which connect many of the large cities. The intermediate cities and small towns on the outer islands have a relatively higher population growth rate compared with those in Java, which might suggest that those towns and cities are playing a more significant role in regional development.