Ethernet over SDH技术高速网络的研究

简要叙述了Ethernet over SDH系统的原理结构,阐述了实现这一系统的几种关键技术,如采用LAPS协议帧的映射过程和采用SDL协议帧的映射过程,用级联实现动态带宽分配等.     

Signaling Role of Mitochondrial Enzymes and Ultrastructure in the Formation of Molecular Mechanisms of Adaptation to Hypoxia

This study was the first comprehensive investigation of the dependence of mitochondrial enzyme response (catalytic subunits of mitochondrial complexes (MC) I-V, including NDUFV2, SDHA, Cyt b, COX1 and ATP5A) and mitochondrial ultrastructure in the rat cerebral cortex (CC) on the severity and duration of in vivo hypoxic exposures. The role of individual animal’s resistance to hypoxia was also studied. The respiratory chain (RC) was shown to respond to changes in environmental [O₂] as follows: (a) differential reaction of mitochondrial enzymes, which depends on the severity of the hypoxic exposure and which indicates changes in the content and catalytic properties of mitochondrial enzymes, both during acute and multiple exposures; and (b) ultrastructural changes in mitochondria, which reflect various degrees of mitochondrial energization. Within a specific range of reduced O₂ concentrations, activation of the MC II is a compensatory response supporting the RC electron transport function. In this process, MC I develops new kinetic properties, and its function recovers in hypoxia by reprograming the RC substrate site. Therefore, the mitochondrial RC performs as an in vivo molecular oxygen sensor. Substantial differences between responses of rats with high and low resistance to hypoxia were determined.     

A Study of the Partially Adaptive Concentric Ring Array

Concentric ring arrays can provide effective beamforming and achieve frequency invariant beampatterns. For long range signal acquisition, the array has a large number of array elements, and partial adaptation is often necessary to increase tracking ability and reduce computation. The topic of this paper is the study of a partially adaptive concentric ring array for three-dimensional audio signal acquisition. We develop the partially adaptive array through partition matrix formulation, provide the associated adaptive structure, and derive the steady state residual interference and noise power that can serve as a criterion to evaluate different partition structures. A comparison of several partition schemes using the criterion is given, and the theoretical results are supported by simulations. The research is supported by US AFOSR under contract FA9550-04-C-0058 and partially supported by the Polytechnic University of Puerto Rico.     

Within-Host Adaptation of Staphylococcus aureus in a Bovine Mastitis Infection Is Associated with Increased Cytotoxicity

Within-host adaptation is a typical feature of chronic, persistent Staphylococcus aureus infections. Research projects addressing adaptive changes due to bacterial in-host evolution increase our understanding of the pathogen’s strategies to survive and persist for a long time in various hosts such as human and bovine. In this study, we investigated the adaptive processes of S. aureus during chronic, persistent bovine mastitis using a previously isolated isogenic strain pair from a dairy cow with chronic, subclinical mastitis, in which the last variant (host-adapted, Sigma factor SigB-deficient) quickly replaced the initial, dominant variant. The strain pair was cultivated under specific in vitro infection-relevant growth-limiting conditions (iron-depleted RPMI under oxygen limitation). We used a combinatory approach of surfaceomics, molecular spectroscopic fingerprinting and in vitro phenotypic assays. Cellular cytotoxicity assays using red blood cells and bovine mammary epithelial cells (MAC-T) revealed changes towards a more cytotoxic phenotype in the host-adapted isolate with an increased alpha-hemolysin (α-toxin) secretion, suggesting an improved capacity to penetrate and disseminate the udder tissue. Our results foster the hypothesis that within-host evolved SigB-deficiency favours extracellular persistence in S. aureus infections. Here, we provide new insights into one possible adaptive strategy employed by S. aureus during chronic, bovine mastitis, and we emphasise the need to analyse genotype–phenotype associations under different infection-relevant growth conditions.     

Changes in rumen microbiota composition and in situ degradation kinetics during the dry period and early lactation as affected by rate of increase of concentrate allowance

Changes in rumen microbiota and in situ degradation kinetics were studied in 12 rumen-cannulated Holstein Friesian dairy cows during the dry period and early lactation. The effect of a rapid (RAP) or gradual (GRAD) postpartum (pp) rate of increase of concentrate allowance was also investigated. Cows were fed for ad libitum intake and had free access to a mixed ration consisting of chopped wheat straw (dry period only), grass silage, corn silage, and soybean meal. Treatment consisted of either a rapid (1.0 kg of dry matter/d; n = 6) or gradual (0.25 kg of dry matter/d; n = 6) increase of concentrate allowance (up to 10.9 kg of dry matter/d), starting at 4 d pp. In whole rumen contents, bacterial community composition was assessed using samples from 50, 30, and 10 d antepartum (ap), and 3, 9, 16, 30, 44, 60, and 80 d pp, and protozoal and archaeal community composition using samples from 10 d ap, and 16 and 44 d pp. Intake of fermentable organic matter, starch, and sugar was temporarily greater in RAP than GRAD at 16 d pp. Bacterial community richness was higher during the dry period than during the lactation. A rapid increase in concentrate allowance decreased bacterial community richness at 9 and 16 d pp compared with a gradual increase in concentrate allowance, whereas from 30 d pp onward richness of RAP and GRAD was similar. In general, the relative abundances of Bacteroidales and Aeromonadales were greater, and those of Clostridiales, Fibrobacterales, and Spirochaetales were smaller, during the lactation compared with the dry period. An interaction between treatment and sampling day was observed for some bacterial community members, and most of the protozoal and archaeal community members. Transition to lactation increased the relative abundance of Epidinium and Entodinium, but reduced the relative abundance of Ostracodinium. Archaea from genus Methanobrevibacter dominated during both the dry period and lactation. However, during lactation the abundance of the methylotrophic Methanomassiliicoccaceae and Methanosphaera increased. The in situ degradation of organic matter, neutral detergent fiber, starch, and crude protein was neither affected by treatment nor by transition from the dry period to lactation. Results show that the composition of the rumen microbiota can change quickly from the dry period to the lactation period, in particular with a rapid increase in fermentable substrate supply postpartum, but this was not associated with changes in rumen degradation kinetics.     

Trial-to-trial modulations of the Simon effect in conditions of attentional limitations: Evidence from dual tasks.

Interference effects are reduced after trials including response conflict. This sequential modulation has often been attributed to a top-down mediated adaptive control mechanism and/or to feature repetition mechanisms. In the present study we tested whether mechanisms responsible for such sequential modulations are subject to attentional limitations under dual-task situations. Participants performed a Simon task in mixed single- and dual-task contexts (Experiment 1), in blocked contexts with dual-task load either, in trialN (Experiment 2a), in trialN – 1 (Experiment 2b), or in both trials (Experiment 3). Results showed that the occurrence of a sequential modulation did not depend on dual-task load per se as it occurred predominantly in conditions of lowest and highest task load. Instead, task factors such as the repetition of task episodes and stimulus-response repetitions determined whether a sequential modulation occurred. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

中厚板生产中的道次修正模型

针对传统板对板的自学习模型不能修正轧件个体差异的缺陷,提出了道次对道次的道次修正模型。该模型利用上道次的实测轧制数据,如实测轧制力、轧制速度、测温仪温度等,通过道次出口厚度再计算模块、钢板温度修正模块和轧制力短期修正模块精确计算出当前钢板的实际状态,然后通过剩余道次再计算模块对后续未轧道次的辊缝进行修正。实际应用表明,该道次修正模型投入使用后,轧制力预报精度和成品厚度精度有了很大提高。     

支持局部更新的双向内容适配策略

内容适配旨在解决融合环境下多种终端兼容问题,现有的内容适配策略在用户通过受限终端进行更新时会造成信息丢失。提出一种支持局部更新的双向内容适配策略,该策略基于DOM树建立统一的存储模型对元数据和适配实例进行存储,当受限终端发起更新时,通过比较DOM树中的节点对元数据进行局部更新。实验结果表明,相比现有策略,支持局部更新的内容适配策略在大部分情况下可以减少60%以上的信息丢失。     

直线电机伺服系统的自适应模糊摩擦补偿

针对受摩擦力影响,接触运动的直线电机在低速运动时速度常会不平稳、系统控制精度降低的问题,提出一种自适应摩擦补偿方法.通过模糊模型参数的自适应调整,实现摩擦力值的在线估计,并据此进行摩擦补偿,以克服摩擦对电机性能的影响.该方法采用复合自适应律,同时利用系统输出误差与参数估计误差的相关信息进行参数调整,以提高模糊模型参数收敛的速度,使参数估计值在一定条件下收敛到最优值.并在理论上证明了该方法的闭环稳定性与参数收敛性.仿真结果表明,此方法能实现摩擦的在线估计与补偿,从而提高直线电机的控制性能.