基于MPEG-21数字项改编的UMA系统

介绍了UMA系统的基本功能以及不同的视频格式和网络状况给UMA系统带来的失配问题.阐述了在UMA系统中引入MPEG-21的第7部分--数字项改编,来实现资源改编引擎以支持转换编码工具和资源改变引擎QoS的实现,从而解决失配问题.     

0Cr21Ni6Mn9N奥氏体不锈钢的应变强化行为

研究了不同氮含量的0Cr21Ni6Mn9N奥氏体不锈钢的塑性流变行为。结果表明,其形变强化特性可用Ludwigson模型来表示。钢在不同的应变下表现出不同的塑性流变行为,存在一个瞬变应变。当应变量低于它时,流变行为与Ludwik方程存在一个正偏差;而应变量高于它时,则符合Ludwik模型。造成这一差异的主要原因是位错滑移模式发生了改变,低于瞬变应变时为单系滑移,高于瞬变应变时为多系滑移。氮对位错滑移模式的影响主要表现为对瞬变应变的影响。随氮含量的增加,瞬变应变被推向更高的水平,这意味着氮原子使位错在更大的应变下才产生多系滑移和交滑移。     

Optimized RTL Code Generation from Coarse-Grain Dataflow Specification for Fast HW/SW Cosynthesis

This paper presents a new methodology of automatic RTL code generation from coarse-grain dataflow specification for fast HW/SW cosynthesis. A node in a coarse-grain dataflow specification represents a functional block such as FIR and DCT and an arc may deliver multiple data samples per block invocation, which complicates the problem and distinguishes it from behavioral synthesis problem. Given optimized HW library blocks for dataflow nodes, we aim to generate the RTL codes for the entire hardware system including glue logics such as buffer and MUX, and the central controller. In the proposed design methodology, a dataflow graph can be mapped to various hardware structures by changing the resource allocation and schedule information. It simplifies the management of the area/performance tradeoff in hardware design and widens the design space of hardware implementation of a dataflow graph. We also support Fractional Rate Dataflow (FRDF) specification for more efficient hardware implementation. To overcome the additional hardware area overhead in the synthesized architecture, we propose two techniques reducing buffer overhead. Through experiments with some real examples, the usefulness of the proposed technique is demonstrated.

非均匀介质谐振器的谐振频率分析与FDTD方法

为了揭示非均匀介质谐振器的谐振频率与非均匀介质的特性之间的关系,首先基于Matlab编码,应用时域有限差分法(FDTD),对一个均匀介质的谐振器进行了模型分析和结果仿真,与实测结果对比,仿真结果显示了FDTD方法的有效性。然后建立一个具有横向平面分层式结构的非均匀介质谐振器模型,通过调节各层介质不同的厚度比例,发现可以用两种固定的介电常数相异的介质来获取所期望的谐振频率。这个分析和模拟结果有助于设计模型简单、尺寸规格相近但谐振频率各异的介质谐振器。     

FACIES HETEROGENEITIES IN A RAMP CARBONATE RESERVOIR ANALOGUE: A NEW HIGH‐RESOLUTION APPROACH FOR 3D FACIES MODELLING

In contrast to the conventional view that facies distribution patterns on carbonate ramps are relatively simple, outcrop analogue studies point to a high degree of internal facies complexity. Depending on the diagenetic overprint, this complex pattern may result in reservoir compartmentalization due to the presence of interflow baffles. The often subseismic scale heterogeneities may not be included in conventional reservoir modelling. In order to evaluate how facies heterogeneities in shoal reservoirs can be modelled realistically, this paper presents a facies modelling workflow which includes a new approach to the design of training images for multiple‐point statistics (MPS). The workflow was developed in the course of a reservoir outcrop analogue study of a Ladinian (Middle Triassic) coquinadominated shoal complex in SW Germany which was deposited on an epicontinental, gently inclined carbonate ramp. The data set was based on an intensive field study and includes 3D facies and sequence stratigraphic analyses of the largest shoal complex in the Quaderkalk Formation (Upper Muschelkalk). This several metre thick shoal complex represents a subseismic scale, bioclast‐rich reservoir analogue and has a very heterogeneous facies pattern. Integrating 1D facies logs and sequence stratigraphic trends from tens of outcrop sections and cores, two nested 3D geocellular facies models were produced: (i) a large‐scale (30 × 30 km) model based on truncated Gaussian simulation (TGS); this formed the basis for (ii) a smaller‐scale (10 × 10 km), more detailed model based on multiple point statistics. In addition, a new approach for training image design was developed to honour small‐scale sequence stratigraphic trends and lateral facies patterns observed in modern analogues. Compared to facies patterns in modern analogues, the large‐scale model presents geologically‐feasible facies distribution patterns and geometries, and in addition shows a vertical facies distribution which is similar to the observed sequence stratigraphic architecture of the outcrop data‐set used. Due to the new training image design, the final small‐scale model has a distribution pattern of facies heterogeneities which looks similar to modern facies distributions in the offshore UAE and thus represents a valuable method of producing realistic reservoir facies models. The modelling workflow and the new approach for training image design presented will help to reduce uncertainties in the understanding and modelling of subsurface reservoirs by using a systematic combination of outcrop data and modern analogues, with the consistent application of sequence stratigraphic principles. In addition, this study emphasises the importance of careful training image design, derived from modern analogues, which can be used as realistic inputs in order to optimize multiple point simulations, and which may be applied to producing bioclastic reservoirs such as those located on the Arabian Plate or offshore Brazil.     

TC4-DT及TC21钛合金疲劳裂纹扩展速率的对比分析

为进一步研究航空主承力疲劳结构件损伤容限型钛合金的疲劳裂纹扩展问题,基于新版标准疲劳裂纹扩展试验方法GB/T 6398—2017,对两类损伤容限型钛合金TC4-DT及TC21进行测试。结果表明,低速扩展阶段,TC4-DT较TC21的疲劳裂纹扩展速率更小,宏观断口形貌粗糙度较大。当裂纹尖端应力强度因子范围ΔK处于24～31 MPa·m1/2的初始稳态扩展阶段时,裂纹扩展速率曲线基本重合,TC4-DT较TC21具有更长的稳态扩展区,断口形貌较为平滑。随裂纹长度的增加,应力强度因子范围ΔK约为断裂韧度KIC的50%时,进入失稳扩展阶段,断裂面粗糙度增加。     

CARBONATE RESERVOIR ROCKS AT GIANT OIL AND GAS FIELDS IN SW IRAN AND THE ADJACENT OFFSHORE: A REVIEW OF STRATIGRAPHIC OCCURRENCE AND PORO‐PERM CHARACTERISTICS

SW Iran and the adjacent offshore are prolific petroleum‐producing areas with very large proven oil and gas reserves and the potential for significant new discoveries. Most of the oil and gas so far discovered is present in carbonate reservoir rocks in the Dehram, Khami and Bangestan Groups and the Asmari Formation, with smaller volumes in the Dashtak, Neyriz, Najmeh, Gurpi, Pabdeh, Jahrum, Shahbazan, Razak and Mishan (Guri Member) Formations. The Permo‐Triassic Dehram Group carbonates produce non‐associated gas and condensate in Fars Province and the nearby offshore. The Jurassic – Lower Cretaceous Khami Group carbonates are an important producing reservoir at a number of offshore fields and in the southern Dezful Embayment, and are prospective for future exploration. Much of Iran's crude oil is produced from the Oligo‐Miocene Asmari Formation and the mid‐Cretaceous Sarvak Formation of the Bangestan Group in the Dezful Embayment. This review paper is based on data from 115 reservoir units at 60 oil‐ and gasfields in SW Iran and the adjacent offshore. It demonstrates that the main carbonate reservoir units vary from one‐another significantly, depending on the particular sedimentary and diagenetic history. Ooidal‐grainstones and rudist‐ and Lithocodium‐bearing carbonate facies form the most important reservoir facies, and producing units are commonly dolomitised, karstified and fractured. In general, reservoir rocks in the study area can be classified into six major types: grainstones; reefal carbonates; karstified, dolomitised and fractured carbonates; and sandstones. The stratigraphic distribution of these reservoir rocks was principally controlled by the palaeoclimatic conditions existing at the time of deposition. A comparative reservoir analysis based on core data shows that dolomitised and/or fractured, grain‐dominated carbonates in the Dehram Group, Lower Khami Group and Asmari Formation typically have better reservoir qualities than the Cretaceous limestones in the Upper Khami and Bangestan Groups.     

ZL21滤棒成型机组生产水溶性加胶棒的设备改造

ZL21滤棒成型机组生产水溶性加胶棒时,由于水溶性胶具有含水率高、粘度大、流动性差等特点,造成甩胶轮甩出的水溶胶穿透性差且不均匀、水溶性胶变干后粘结在泵体上导致泵体频繁损坏、铜质的上胶及回胶管路遇水易产生铜锈、烘烤后滤棒易弯曲变形等问题.为此对ZL21成型机组及烘箱进行了6项改造:甩胶电机转速由原来的1400 r/min改为2800 r/min,甩胶轮由单排甩胶孔改为3排甩胶孔;上胶泵由齿轮泵改为蠕动泵,上胶及回胶管路改为增塑网管,加装过滤网和弧形开松杆,优化烘箱参数.改造后应用结果表明,实现了水溶性加胶棒在ZL21成型机组上的正常生产,设备有效作业率达到90％以上,产品质量满足了工艺质量要求,平均质量合格率达到97％以上.     

地表径流速度对城市内涝影响规律

为分析地表径流速度对城市内涝的影响,采用一维地下排水管网与二维城区地形的动态耦合模型,选取大连市某排水区块作为研究区域,设置4种地表径流速度10种设计降雨场景,模拟分析在不同重现期设计降雨及不同地表径流速度下研究区的内涝积水特性。结果表明:随着地表径流速度降低,管道排水压力变小,管道排水达标率最高可提升48.05%,且降雨重现期越短,地表径流流速对管道排水压力的削减效果越明显;地表径流流速对检查井溢流量影响显著,随着地表径流速度降低,检查井溢流量峰值最高可减小2 750 m~3,峰现时间最长可滞后56 min,同时随着降雨重现期增长,地表径流流速对检查井溢流量的削减效果减弱;研究区低、高风险区淹没面积随地表径流速度降低,最高可分别减小1.64万、8.37万m~2,但中风险区淹没面积变化反复。