DDR DRAM削减膝上计算机功耗

看第一眼,你觉得PC100／133与DDRDRAM在省电方面似乎没有什么两样,但仔细分析以后,你会发现DDR是更好的选择。为了探索更高的性能和更低的功耗,膝上计算机的设计正开始从SDRAM（PC10O／133）转向双速率（Doub卜DataRate,DDR）的DDRDRAM。在采用新的DDR做设计时,有几个因素是系统工程师必须考虑的,其中主要的因素是功耗问题。影响设计和布局布线的新结构特点也必须加以考虑。同样重要的是对成本与性能特性的理解。DDR功率分析比较两种不同的存储器系统的功耗是很有意义的,其中一个采用PC133SDRAM,另～个采用266M…     

Optical characterization of a new donor–acceptor type conjugated polymer derived from 3,4-diphenylthiophene

A new donor–acceptor type poly{2-(3,4-didecyloxythiophen-2-yl)-5-[3,4-diphenyl-5-(1,3,4-oxadiazol-2-yl)thiophen-2-yl]-1,3,4-oxadiazole} (P1) has been designed and synthesized starting from thiodiglycolic acid, 1,2-diphenylethane-1,2-dione, and diethyl oxalate through multi-step reactions using precursor polyhydrazide route. The charge-transporting and linear optical property of the polymer has been investigated by cyclic voltammetric, UV–visible, and fluorescence emission spectroscopic studies. The UV–visible absorption spectrum of polymer in thin film form showed maxima at 420 nm. The polymer displayed bluish-green fluorescence both in solution and thin film form. The optical band gap is determined to be 2.27 eV. Third-order nonlinear optical property of the new polymer has been investigated at 532 nm using single beam Z-scan and degenerate four wave mixing (DFWM) techniques with nanosecond laser pulses. The absorptive nonlinearity observed for the polymer P1 is of optical limiting type, which arises due to an “effective” three-photon absorption (3PA) process. The third-order nonlinear optical susceptibility (χ⁽³⁾) of the polymer is found to be 0.831 × 10^–12 esu. Both linear and nonlinear optical studies revealed that the new polymer (P1) is a promising material for applications in photonic devices.     

Langmuir-Blodgett films of C60 and C60O on Silicon: Islands, rings and grains

We show that monolayer-high islands of C₆₀ and C₆₀O can be transferred from Langmuir films on a water or phenol sub-phase to oxide-terminated Si(111) substrates. Faceted islands, in some cases incorporating a foam-like morphology reminscent of that previously observed for Langmuir films at the water-air interface using Brewster angle microscopy, are formed and transferred using small amounts (100-400 μl) of low concentration (of order 10^− 5M) solutions of C₆₀ (or C₆₀O) with low target pressures (~ 10 mN/m). However, worm-like monolayer domains are also observed under identical experimental conditions, indicating the key role that inhomogeneous solvent evaporation plays in the formation of two-dimensional fullerene aggregates on the subphase surface. While Langmuir-Blodgett multilayers of C₆₀ and C₆₀O are both granular, there are significant morphological differences observed between the molecular thin films. In particular, C₆₀O multilayers contain a relatively high density of ring (or “doughnut”) features with diameters in the 100-300 nm range which are not observed for C₆₀. We attribute the origin of these features to dipolar or hydrogen bonding-mediated interactions between the C₆₀O molecules at the water surface.     

A randomized controlled trial study of the ABRACADABRA reading intervention program in grade 1.

This study reports a randomized controlled trial evaluation of a computer-based balanced literacy intervention, ABRACADABRA (http://grover.concordia.ca/abra/version1/abracadabra.html). Children (N = 144) in Grade 1 were exposed either to computer activities for word analysis, text comprehension, and fluency, alongside shared stories (experimental groups), or to balanced literacy approaches delivered by their classroom teachers (control group). Two computer-based interventions—a phoneme-based synthetic phonics method and a rime-based analytic phonics method—were contrasted. Children were taught 4 times per week for 12 weeks in small groups. There were significant improvements in letter knowledge in the analytic phonics program and significant improvements in phonological awareness, listening comprehension, and reading comprehension at immediate posttest and in phonological awareness and reading fluency at a delayed posttest in the synthetic phonics program. Effect size analyses confirmed that both interventions had a significant impact on literacy at both posttests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Florida Supreme Court: Mediating senior judges must be retrained

Russ Bleemer and Philip Sutter, of New York, analyze the effects of new mediation training and disclosure rules in Florida targeted at state judges on senior status. Also, the Federal Interagency ADR Working Group releases for comment three new practice guides, with implications for anyone doing business with the government, and a followup item discussing the latest on California's arbitrator ethics standards, which are about to be revised.     

A pilot-scale evaluation of magnetic ion exchange treatment for removal of natural organic material and inorganic anions

The objective of this research was to evaluate a magnetic ion exchange process (MIEX) for the removal of natural organic material (NOM) and bromide on a continuous-flow pilot-scale basis under different operating conditions and raw water characteristics. The most important operating variable was the effective resin dose (ERD), which is the product of the steady-state resin concentration in the contactor and the regeneration ratio. The raw water employed in this study had a moderate concentration of ultraviolet (UV)-absorbing substances and dissolved organic carbon (DOC), and a low turbidity, alkalinity, and concentration of competing anionic species. Experiments were conducted using the ambient raw water and raw water spiked with bromide, chloride, and sulfate. Substantial removal of UV-absorbing substances and DOC was achieved at ERDs as low as 0.16mL/L. Moderate bromide removal was achieved, depending on the ERD. Increasing the sulfate concentration resulted in decreased removal of UV-absorbing substances, DOC, and bromide. Consistent results were observed between the continuous-flow pilot plant tests and batch equilibrium studies.     

Characterization of fine particle sources in the Great Smoky Mountains area

A source apportionment study to characterize sources of fine particles in the Great Smoky Mountains area was conducted analyzing ambient PM(2.5) (particulate matter< or =2.5 microm in aerodynamic diameter) speciation data collected at a Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring site. A total of 1442 samples collected between March 1988 and December 2003 analyzed for 30 elemental species were analyzed with the application of the positive matrix factorization (PMF). Eight major sources were extracted: summer-high secondary sulfate (55%), carbon-rich secondary sulfate (16%), summer-low secondary sulfate (2%), gasoline vehicle emissions (13%), diesel emissions (1%), airborne soil (6%), industry (5%), and secondary nitrate (2%). The contributions from the carbon-rich secondary sulfate particles are likely a combination of local and regional influences of the biogenic as well as anthropogenic secondary particles. The compositional profiles for gasoline vehicle and diesel emissions are similar to those identified in other US areas. Backward trajectories indicate that the high impacts of airborne soil were likely caused by Asian and Saharan dust storms. This study would assist in the implementation plan development for attaining the air quality standards for PM(2.5), regional haze rule planning, and source-specific community epidemiology.     

Physical,Thermal and Sorption Profile of Starch Obtained from Tacca leontopetaloides

The purpose of this study was to elucidate functional properties of starch granules obtained from tubers of Tacca leontopetaloides and compare them to a commercially available maize starch. Scanning electron microscopy (SEM), particle size analysis, X‐ray powder diffraction (XRPD), gravimetric moisture sorption, and differential scanning calorimetry (DSC) were used to characterize the samples. Tacca starch exhibited a monomodal distribution of irregularly shaped granules with a mean particle size of 2.64 µm. The spherulites of both samples indicated an A‐type pattern, with the degree of crystallinity estimated to be 35% for tacca starch and 38% for maize starch. The moisture sorption profile of both samples was analyzed according to the Guggenheim, Anderson and de Boer (GAB) equation. GAB analysis estimated the monolayer coverage for tacca and maize starch to be 0.0928 g/g and 0.0856 g/g, respectively. The gelatinization parameters of tacca starch were found to be 65.57 – 68.56 – 73.10°C while that of maize starch were 67.30 – 70.97 – 76.25°C. The results of DSC studies indicate that the associative forces that stabilize the granule structure in tacca starch are weaker than those in maize starch. The results obtained in this study establish the fundamental characteristics of tacca starch and suggest that further exploration of its potential for use in a variety of fields is warranted.     

Proportional degradation services in wireless/mobile adaptive multimedia networks

Adaptive multimedia services are very attractive since resources in wireless/mobile networks are relatively scarce and widely variable, and more importantly the resource fluctuation caused by mobility and channel fading can be mitigated using adaptive services. Therefore, there are extensive research activities on Quality of Service (QoS), call admission control, as well as bandwidth degradation and adaptation for adaptive multimedia services in wireless/mobile networks in recent years. However, fairness of bandwidth degradation has largely been ignored in previous work and remains an important issue in adaptive multimedia service provisioning. In this paper, we propose and study proportional degradation service provisioning in wireless/mobile networks that offer multiple classes of adaptive multimedia services. The proposed proportional degradation fairness model guarantees the proportional bandwidth degradation among different classes of services. Two proportional degradation scenarios are studied in this paper. In the first scenario, we study the proportional degradation provisioning with two QoS parameters for adaptive multimedia: the degradation ratio (DR) and the degradation degree (DD). In the second scenario, we study the proportional degradation provisioning with a new QoS parameter for adaptive multimedia: the degradation area (DA). For each scenario, based on the QoS parameters, proportional degradation adaptation algorithms are proposed to approximate the proportional degradation model, to fairly adapt calls' degradations, to utilize the system resource efficiently, as well as to optimize QoS parameters. Performance studies show that in the first scenario, proportional DR has been achieved very well, whereas proportional DD has not been well achieved. In other words, DR outperforms DD in terms of proportional degradation. In the second scenario, proportional DA has been well achieved. Furthermore, bandwidth resources have been efficiently utilized and DA has been minimized. Copyright © 2004 John Wiley & Sons, Ltd.