复杂铅铋精矿氧化熔池熔炼过程的热力学模拟

采用热力学平衡模拟方法研究复杂铅铋精矿富氧熔池熔炼过程中的元素分配行为,分析氧料比(OFR)和硫分压(pSO2)对Bi、Pb、As、Sb、Cu和Ag分配行为的影响,并对比模拟计算结果与工业数据.结果表明,该过程中OFR在6.3～6.8 kmol/t之间有利于最大化Bi、Pb、Cu和Ag在金属相中的分配,进一步增加OFR...     

High strength,high elongation steels obtained by hot deformation and quenching and partitioning

Abstract

An effective means to achieve energy savings, environmental protection and improved safety in automobiles is to explore higher strength steels having low cost and better processability and service performance. Two routes to develop advanced high strength steels combining ultrahigh strength with appropriate plasticity and characterised by low cost and good quality are proposed: hot stamping followed by quenching and partitioning (HS-Q&P) and deformation induced ferrite transformation followed by Q&P (DIFT-Q&P).     

The three Rs of river ecosystem resilience: Resources,recruitment, and refugia

Resilience in river ecosystems requires that organisms must persist in the face of highly dynamic hydrological and geomorphological variations. Disturbance events such as floods and droughts are postulated to shape life history traits that support resilience, but river management and conservation would benefit from greater understanding of the emergent effects in communities of river organisms. We unify current knowledge of taxonomic‐, phylogenetic‐, and trait‐based aspects of river communities that might aid the identification and quantification of resilience mechanisms. Temporal variations in river productivity, physical connectivity, and environmental heterogeneity resulting from floods and droughts are highlighted as key characteristics that promote resilience in these dynamic ecosystems. Three community‐wide mechanisms that underlie resilience are (a) partitioning (competition/facilitation) of dynamically varying resources, (b) dispersal, recolonization, and recruitment promoted by connectivity, and (c) functional redundancy in communities promoted by resource heterogeneity and refugia. Along with taxonomic and phylogenetic identity, biological traits related to feeding specialization, dispersal ability, and habitat specialization mediate organism responses to disturbance. Measures of these factors might also enable assessment of the relative contributions of different mechanisms to community resilience. Interactions between abiotic drivers and biotic aspects of resource use, dispersal, and persistence have clear implications for river conservation and management. To support these management needs, we propose a set of taxonomic, phylogenetic, and life‐history trait metrics that might be used to measure resilience mechanisms. By identifying such indicators, our proposed framework can enable targeted management strategies to adapt river ecosystems to global change.     

甜菜干物质生产模拟的初步研究

本项研究建立了一个概要模型,使用Excel软件模拟河西走廓甜菜干物质生产。从光合速率着手,促成干物质积累,除去呼吸消耗,用适当方程使茎叶和块根的物质分配达到一定的比例,收获时块根产量、蔗糖产量和根叶比达到本地较好条件下的水平。通过改变光合速率和根叶物质分配比的方程式,可以模拟不同条件下甜菜干物质生产情况。     

Optimum stand density of Leucaena leucocephala for wood production in Andhra Pradesh, Southern India

Leucaena leucocephala is widely used as raw material for the manufacture of paper and packaging material and in biomass based power plants in the state of Andhra Pradesh, Southern India. Experiments were conducted to study the affect of tree density on the growth, biomass partitioning and wood productivity. Six treatments 1 × 1 m, 1.3 × 1.3 m, 3 × 0.75 m, 3 × 1 m, 5 × 0.8 m and 3 × 2 m corresponding to a tree density of 10,000, 6666, 4444, 3333, 2500 and 1666 were evaluated with leucaena variety K636. At 51 months after planting, spacings significantly influenced tree height, diameter at breast height (DBH), number of branches and biomass partitioning. Wider tree rows resulted in greater tree height and diameter growth resulting in higher per plant productivity. At harvest, 70% of trees in 3 × 2 m attained a diameter of more than 7.5 cm, while 35% of the trees attained the same DBH in 1 × 1 m spacing. Increased spacing levels decreased the relative amount of growth allocated to the bole of the tree. Marketable biomass yield was highest with 1 × 1 m spacing. Spacing of 3 × 0.75 m produced marketable biomass comparable to that of 1 × 1 m and greater proportion of stems with more than 5 cm diameter. Leucaena can be grown at 3 × 0.75 m spacing either for pulpwood or fuelwood depending on the prevailing market prices and demand.     

基于谱聚类的无功电压分区和主导节点选择

传统无功电压分区常采用基于潮流运算的聚类算法。该算法计算较复杂,且难以体现出电网拓扑结构。针对这些问题,提出一种基于复杂网络理论的谱聚类无功电压分区新算法。该算法首先基于电网的节点导纳矩阵构建无功电压分区模型,其次利用谱聚类对模型进行分析得到低维度聚类样本,再应用改进的K-means 聚类算法获取分区方案。为了确保分区方案的可行性,基于模块度、无功平衡与无功储备等三个指标建立了一个评价体系,并对分区方案进行校验。为了提高主导节点选择的准确度,引入了程度中心性评价指标。通过IEEE-39节点标准测试系统对算法进行仿真,仿真结果验证了算法的可行性与优越性。     

Low-power state encoding for partitioned FSMs with mixed synchronous/asynchronous state memory

Partitioned finite state machine (FSM) architectures in general enable low-power implementations and it has been shown that for these architectures, state memory based on both synchronous and asynchronous storage elements gives lower power consumption compared to their fully synchronous counterparts. In this paper we present state encoding techniques for a partitioned FSM architecture based on mixed synchronous/asynchronous state memory. The state memory, in this case, is composed of a synchronous local state memory and an asynchronous global state memory. The local state memory uses synchronous storage elements and is shared by all sub-FSMs. The global state memory operates asynchronously and is responsible for handling the interaction between sub-FSMs. Even though the partitioned FSM contains the asynchronous mechanism, its input/output behaviour is still cycle by cycle equivalent to the original monolithic synchronous FSM. In this paper, we discuss the low-power state encoding method for the implementation of partitioned FSM with mixed synchronous/asynchronous state memory. For the local state assignment a, what we call, state-bundling procedure is presented to enable states residing in different sub-FSMs to share the same state codes. Based on state-bundles, two state encoding techniques, in which one is the employment of binary encoding and the other is the further optimization for low power, are compared.     

Progressive filling partitioning and mapping algorithm for Spark based on allocation fitness degree

The job execution mechanism of Spark was analyzed,task efficiency model and Shuffle model were established,then allocation fitness degree (AFD) was defined and the optimization goal was put forward.On the basis of the model definition,the progressive filling partitioning and mapping algorithm (PFPM) was proposed.PFPM established the data distribution scheme adapting Reducers’ computing ability to decrease synchronous latency during Shuffle process and increase cluster the computing efficiency.The experiments demonstrate that PFPM could improve the rationality of workload distribution in Shuffle and optimize the execution efficiency of Spark.     

CTU depth decision algorithms for HEVC: A survey

High Efficiency Video Coding (HEVC) surpasses its predecessors in encoding efficiency by introducing new coding tools at the cost of an increased encoding time-complexity. The Coding Tree Unit (CTU) is the main building block used in HEVC. In the HEVC standard, frames are divided into CTUs with the predetermined size of up to 64 × 64 pixels. Each CTU is then divided recursively into a number of equally sized square areas, known as Coding Units (CUs). Although this diversity of frame partitioning increases encoding efficiency, it also causes an increase in the time complexity due to the increased number of ways to find the optimal partitioning. To address this complexity, numerous algorithms have been proposed to eliminate unnecessary searches during partitioning CTUs by exploiting the correlation in the video. In this paper, existing CTU depth decision algorithms for HEVC are surveyed. These algorithms are categorized into two groups, namely statistics and machine learning approaches. Statistics approaches are further subdivided into neighboring and inherent approaches. Neighboring approaches exploit the similarity between adjacent CTUs to limit the depth range of the current CTU, while inherent approaches use only the available information within the current CTU. Machine learning approaches try to extract and exploit similarities implicitly. Traditional methods like support vector machines or random forests use manually selected features, while recently proposed deep learning methods extract features during training. Finally, this paper discusses extending these methods to more recent video coding formats such as Versatile Video Coding (VVC) and AOMedia Video 1(AV1).     

改进的二维增强贪婪软硬件划分算法

针对嵌入式系统中的单处理器和单ASIC体系结构,将软硬件划分问题抽象为MKP模型,通过扩展其边界的维数,引入二维的贪婪算法来解决软硬件划分问题。算法旨在满足硬件面积约束、功耗约束和存储空间需求约束的前提下使系统的运行时间最优,算法的时间复杂度降低到O（log n·log n）。算法基于代表功能块粒度的控制数据流图（CFG）,摒弃了传统的面向软件或硬件的方法,给出了一种新的选择初始状态的方法,该方法将关键节点映射到软件,其余的用硬件实现,因缩小了算法的搜索空间,从而进一步提高了算法的运行速度。最后进行对比实验,实验结果证明该算法在运行时间和稳定性方面均优于遗传算法和模拟算法。