高黏度聚酯熔体热交换器在直纺中的应用

从静态混合器的结构原理、特性及在热交换器上的应用出发,探讨了高黏度聚酯熔体热交换器（含静态混合器的热交换器）的设计和选用方法,介绍了高黏度聚酯熔体热交换器在大容量聚酯熔体直接纺丝引进线和国产化增量改造线上的应用。通过分析、计算可知,高黏度聚酯熔体热交换器能有效解决因增量提速造成熔体温度升高以及熔体在输送过程中温度和速度分布不匀、分散和混合不均等问题;高黏度聚酯熔体热交换器比熔体夹套管有更高的热交换效果,静态混合器为串联型的高黏度聚酯熔体热交换器比并联型的具有更好的传热效果。     

高气液比电泵井的液量计量新方法研究

采用自动化手段计量电泵井的液量时,国内软件多采用压差法计量模型。而对于海上高气液比电泵井,单纯的压差法计量已经满足不了应用条件。本文介绍了一种与多相流计算相结合的新计量模型,经过验证,应用效果良好。     

超临界流体技术制备中药超细粉体

颗粒细、药效好、用量少已成为现代中药制剂的必然发展趋势。利用近年提出的超临界流体辅助雾化过程成功制备出了中药复方肝炎制剂的超细粉体,系统分析了混合器压力和温度及进液速率对微粒形态、粒径和粒径分布的影响。结果表明:利用超临界辅助雾化过程,以水和乙醇的混合溶液为溶剂,可制备出粒径范围为1.0～5.0μm的复方肝炎超细粉体,且大部分粒子形态呈完整的球形。各影响因素对粒径及粒径分布均有不同程度的影响,其中混合器压力及溶液浓度对粒径及粒径分布的影响最明显,进液速率次之,混合器温度的影响较小。在操作范围内较为理想的工艺条件为混合器压力为14 MPa,温度为60℃,进液速率为4.5 mL/min。     

丙烯酸残液焚烧炉防堵塞雾化喷嘴的设计

根据丙烯酸残液焚烧炉雾化喷嘴的基本要求,提出防堵塞雾化喷嘴的设计思路和喷嘴设计遵循的原则。设计防堵塞结构,计算出残液喷口面积、雾化剂喷口面积及混合室尺寸等雾化喷嘴的结构尺寸,经过实际运行,达到了预期的效果。     

局部反循环打捞装置数值模拟

为了明确常规局部反循环洗井装置在井下形成反循环的机理及其目前洗井效果不理想的原因,解决其在应用过程中碎屑提取率低的问题,采用计算流体力学方法,建立该装置洗井作业时的孔底固液两相流场计算模型,分析液相洗井介质在冲洗碎屑过程中的压力场、速度场分布及湍流特征。模拟计算得出:液相洗井介质的压力、流速及湍动能耗散主要发生在进入孔底流场前的两次出水孔换向过程中,导致其对孔底中部的碎屑冲洗能力不足,部分碎屑滞留在孔底中部。为改善反循环洗井装置的洗井效果,可改进下出水孔的结构,将下出水孔位置适当下移或缩小下出水孔直径,通过增大孔底处洗井介质流速来提升其对碎屑的携带能力。研究结果可为局部反循环打捞装置的优化设计提供参考。     

基于挠度控制的提纯塔集液盘的结构设计

文章以某多晶硅生产公司直径为2600mm的提纯塔集液盘的改造为背景,应用ANSYS Workbench软件建立了三种不同结构形式的集液盘挠度的计算模型,并根据模型计算结果,从对集液盘挠度进行控制的角度出发,对三种不同结构形式的集液盘的挠度进行了比较和分析。最后,借鉴塔盘挠度控制的相关要求,以比较分析后的结果作为理论依据,辅助完成对集液盘结构改造方案的优选。     

管柱式旋流气液分离器的应用研究

针对中原油田计量站原油计量过程中存在计量工艺流程不完善、含水率误差大、自动化程度低等问题,采用多相流分离计量原理,综合应用管柱式旋流气液分离器、模拟分析多相流流体动力形态、质量流量计等技术,经现场试验应用,取得了良好测量效果,解决了中高含水期油田油井产出物精确计量问题,完善了石油多相流混相输送工艺技术。     

油气钻井用液动锤优化设计研究

由于油气钻井井深较深、井眼尺寸较大、井下工况复杂,传统液动锤在油气钻井中应用易出现提速效果不明显、使用寿命短等问题。为此研制了大功率、长寿命油气钻井用液动锤。通过建立液动锤的动力学模型,编制液动锤的性能参数仿真计算程序,设计出液动锤的结构参数组合。理论分析结果表明,液动锤冲击功率达10k W。台架试验结果表明,液动锤工作原理可行,冲击功率与理论分析结果相符合。     

聚合反应机静态混合器的延时冲洗改造

静态混合器NY11的稳定运行,将会对聚合机的工况稳定和产品品质稳定产生深远的影响。聚合机停车后,静态混合器拆除清理困难,时间把握不好,容易引发次生事故;聚合机开车前,静态混合器安装困难,备件消耗大,采购周期长,价格贵。应工艺要求在WY12的KCM控制器停车输入信号之前加一个延时继电器,当来自聚合机或研磨的停车信号发出时,WY12会延时90秒后再停车,以达到停车冲洗NY11的目的。     

高压天然气管道破裂时气体扩散规律和气液分离技术进展

采用国际上著名的流动与传热商业软件Fluent5.4对高压天然气管道破裂时天然气的扩散规律进行了数值模拟，所采用的数学模型为无化学反应的燃烧计算模型。模拟结果表明，取50％和15％为甲烷的爆炸上、下限，甲烷的危险范围是Fd,泄漏点为中心，半径14-23．5m宽度9.5m的圆环范围内。污染物在大气中的浓度与平均风速成反比，风的作用在地面附近影响效果不太明显；随着高度的增加，影响效果将不断增强。     

增强Linux系统安全性的措施

L inux系统的安全取决于系统管理员如何来管理它。本文探讨了一系列可以增强安全性的技巧与策略 ,包括 :系统安装原则、BIOS安全、口令安全策略、设计帐户自动注销功能、文件系统和日志安全策略、使用 SSH及 TCP-WRAPPERS,隐藏系统信息、删除所有特殊帐户、关闭控制台程序、限制系统中的 SUID/ SGID程序等。本文最后向 L inux系统管理员提出了一些安全管理方面的建议     

CIS与现代企业管理美学

概括性介绍了 ＣＩＳ（Ｃｏｒｐｏｒａｔｅ Ｉｄｅｎｔｉｔｙ Ｓｙｓｔｅｍ）的三大基本组成，并阐述了它与现代企业管理密不可分的相互联系及所处的举足轻重的地位，指出导入ＣＩＳ是现代企业谋求发展的重要手段。     

Divergent patterns of engagement in Internet standardization: Japan,Korea and China

This article analyzes the engagement of Japanese, Korean and Chinese participants in the development of Internet standards at IETF on the basis of four quantitative metrics: attendance, patenting, authorship and leadership. The results are strikingly divergent. Japanese involvement in Internet standardization began early and Japan was, for many years, second only to the U.S. in terms of IETF participation. Though Japanese participation has declined since the early 2000s, Japan remains a major contributor to IETF standardization. Korean involvement in IETF has always been significant, but below the levels of Japan and major European countries. Korean participation in IETF has also declined over the past decade, and has been dominated by one firm, Samsung. Though meaningful Chinese involvement in IETF did not begin until the mid-2000s, it has rapidly expanded in recent years. Today, China is a major player in numerous areas of Internet standardization in terms of three metrics (participation, patenting and leadership), and is rapidly gaining in terms of document authorship as well. Most of China׳s recent IETF involvement can be attributed to Huawei, though other Chinese firms have recently begun to increase their participation in the organization. Thus, contrary to some views that China׳s engagement with standardization is primarily one of indigenous innovation and “catching up”, China׳s experience with IETF demonstrates deliberate and effective engagement with a major Western standards-development organization on its own terms.     

Comparing FTTH access networks based on P2P and PMP fibre topologies

There is an ongoing discussion in the market which Next Generation Access (NGA) architecture best suits future needs and which investment and cost differences exist. The discussion can be subsumed as P2P vs. GPON, which is somewhat misleading as this article reveals. The discussion is driven by the fact that the high capital cost and the long asset life time of fibre mean that the technology choices made today will dominate the opportunities for telecommunication business of all market players, incumbents, competitors, content providers and business and residential users for many years in the future.The paper analyzes the cost and other differences between Fibre-to-the-Home (FTTH) access network architectures and their related different wholesale approaches by using the well-known and understood steady state approach applied in other NGA analyses in the past. In addition to the steady state analysis a dynamic cost evaluation is included taking into account the different investment behaviour of the FTTH architectures over time. The results describe investment and cost differences between architectures, incumbents and wholesale based competitive operators. The analysis has been performed for different geotypes (clusters) of decreasing population density in a representative European settlement structure.     

快速成形技术的应用及热点分析

基于快速成形技术的原理,展示了快速成形技术在快速模具制造、金属零件直接成形、反求工程等领域的广泛应用,总结了快速成形制造技术研究的热点,即研发新材料和新设备、提高成形精度、建立RPM的反求工程系统、建立成形技术的统一标准和扩大成形技术的应用领域。     

Whose Image is it Anyway?: Some Considerations of the Curricular Importance of Subject Image in Secondary School Design and Technology Education

This paper explores the idea that a sense of school subject image is a necessary feature of curriculum management and a potent force for change. The discussion centres on the view that all school subjects have an image and that if those intimately involved with the subject do not control the image then someone else does! In such circumstances the image is the product of past encounters and old euphemisms and is unlikely to hold the changed realities.The UK developments in Design and Technology education (the term Design and Technology is used to denote the school subject defined under this heading by the UK National Curriculum, 1995) have created something of an image problem which has interesting international parallels. Some of these problems are due to clearly discernible internal tensions and an ambiguous relationship with other subject areas.Through greater attention to subject image internal controversies might be acknowledged and resolved, relationships with other subject areas can be more meaningfully understood and practitioners can be helped to make sense of curriculum change.     

Diffusion and usage of public e-services in Europe: An assessment of country level indicators and drivers

We analyze the state of the art of indicators on e-government, e-health, e-procurement and e-participation. We survey the main methodological properties of these indicators, and highlight their heuristic potential. Further, we address empirically the issue of the explanation of the availability scores, i.e. how the supply of the various e-services in each country is affected by political, institutional and socio-economic differences, and is followed by actual usage. The econometric analysis uncovers the importance of broadband penetration and higher education as drivers for most of the types of e-services and users (citizens and businesses). Moreover, a corruption-free and agile public sector proves to be an important pre-condition for more effective supply and usage. Despite data limitations and the complexity of the underlying diffusion phenomena, our study is the first truly longitudinal contribution aimed at disentangling the common drivers of such an important phenomenon – the e-services availability and usage across European countries. As such, this work appears useful to inform the policy debate and practice, in a phase characterized by a prospective reorientation of the public e-services provision and policy agenda.     

一种高精度的频率标准比对系统

频率标准源可以提供精确的标准频率,在测定频率标准源的各项性能指标时,要求测试系统必须具有很高的比对精度。所设计的频率标准比对系统采取多级倍频 混频方式使频率偏差逐级扩大后再测量,从而避免了直接进行高次倍频的困难,提高了测量精度,可以对高精度的频率标准的准确度、长短期频率稳定度进行快速测量,是一种高精度时畴参数测量系统。     

Indigenous peoples’ nutrition transition in a right to food perspective

In indigenous communities the nutrition transition characterized by a rapid westernization of diet and lifestyle is associated with rising prevalence of chronic disease. Field work and literature reviews from two different policy environments, Argentina (Jujuy) and Canada (Nunavut), identified factors that add to indigenous peoples’ disease risk. The analytical framework was the emerging human right to adequate food approach to policies and programmes. Indigenous peoples’ chronic disease risk tends to increase as a result of government policies that infringe on indigenous peoples’ livelihoods and territories, undermining their economic system, values and solidarity networks. Policies intended to increase food security, including food aid, may also fuel the nutrition transition. There is a need to explore further the connection between well-intended policies towards indigenous peoples and the development of chronic diseases, and to broaden the understanding of the role that different forms of discrimination play in the westernization of their lifestyles, values and food habits. Food policies that take due account of indigenous peoples’ human rights, including their right to enjoy their culture, may counteract the growth of chronic disease in these communities.     

HSE走进中国石油

企业管理水平的好坏直接影响着企业的经济效益,运用HSE管理能提高企业管理水平,HSE管理模式将健康,安全,环境三者视为一个有机的整体。HSE管理认为人的安全是第一位的,人是创造财富的原动力,是企业的最大财产,HSE管理体系强调的是“蝴蝶效应”。