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外文译文题目(中文) :中间包覆盖剂对钢水纯净度的影响

学院: 材料与冶金学院

专业: 冶金工程

学号: 201002126072

学生姓名: 陈维涛

指导教师: 李光强教授

日期: 二〇一四年六月

近年来,对薄板和涂层钢板质量的要求越来越高。在这方面所面临的一项重要挑战便是如何减少钢水中的非金属夹杂物。

保护中间包中钢液免受污染不仅对提高钢产品的质量尤为重要,而且在避免浸入式水口堵塞和增加连续浇铸的炉数方面有重要作用。为了以稳定的方式供给高洁净度的钢液,对中间包内钢液的去污行为进行了研究,并对保持中间包内钢液洁净机制进行了定量研究。基于所取得的成果,对如何保持中间包中钢液洁净度的工艺进行了研究。

关键词:连铸,炼钢,铸造,夹杂物,洁净钢,空气氧化。

1 前言

确保中间包内钢液的洁净度不仅对生产洁净钢的产品非常重要,而且对防止浸入式水口堵塞有重要影响。中间包具有将钢液分流并通过促进非金属夹杂物的上浮、去除来清洁钢液的功能[1-4]。但中间包冶金也会使钢液中产生新的夹杂物。因此传统研究认为改善中间包内夹杂物的上浮去除工艺以及防止钢液二次污染工艺经是制造洁净钢的先决条件[10-21]。为了充分利用中间包促进夹杂物上浮和去除功能稳定地生产高纯度的洁净钢,联合通过确定某些特殊因素的影响对中间包内污染物的去除的工艺和通过采取适当的措施阻止中间包内新生污染的生成的工艺有着至关重要的作用。

本实验对一实际生产连铸机上中间包中钢液夹杂物进行了研究,并对其形成原因进行了阐述。根据实验的结果,研究了防止钢液被空气氧化工艺及在钢包中使用无污染钢包引流砂工艺在提高中间包中钢液洁净度方面的效果。

2 中间包内夹杂物行为分析结果

在新日铁公司,八幡厂,第三炼钢厂,1号连铸机(两流,60吨中间包)上,浇铸了三炉含铝0.05%的铝镇静钢。在长水口(中间包入口)和浸入式水口(中间包出口)的位置分别用快速冷却取样器对钢液取样。用光学显微镜观察粒径在10μm以上夹杂物的形状(簇状,丛状或球状),并在电子探针显微镜(EPMA)下观察夹杂物的组成。

在第一炉次浇铸前,打开中间包外渣罐上方的滑动式水口并将钢包引流砂排出中间包外。在第一炉浇铸结束,钢包中留大约20吨钢液,以防止钢包中的熔渣被钢液由钢包到中间包的注流卷入中间包中。第二炉和第三炉连铸正常进行。

图1所示为中间包钢液中氧化铝和夹渣含量的变化。随着浇铸的炉次的增加,中间包入口处夹杂物数量增加。中间包入口处和出口处夹杂物数量变化趋势几乎相同,但出口处略低于入口处。这意味着,部分被带入中间包的夹杂物已上浮去除。中间包中氧化铝夹杂物的增加可能是由于钢包引流砂被铝还原以及钢液被空气氧化造成的。

图1 中间包中夹杂物粒径(>10μm)数量变化

假设钢液在中间包内没有受到污染,中间包出口处钢液的理论洁净度[(公式(1)]和根据中间包出口处所取试样得到的中间包钢液的实际洁净度[公式(2)]如图2所示。在光学显微镜下观察到的夹杂物的数量乘以夹杂物与钢液的密度比(/inc

Fe

ρρ)得到相应的夹杂物质量分数(inc W )[22],并以此作为评价钢液洁净

度的指标,见图2。

图2 浇铸过程中中间包中钢液纯净度的实验分析

中间包出口处钢液的理论洁净度

)]1(/)(4/1[2i pi S D Ni α-∑=∏ (1)

中间包出口处钢液的实际洁净度

2

[1/4()/(1)]p i i p

N i D S N α∏=∑-+..........................................(2) Fe inc inc inc A W ρρ/?=. (3)

两者之间的差异即钢液在中间包内的二次污染。因为三次浇铸中间包入口处的气氛是相同的,钢液的理论洁净度很差意味着钢液受到从钢包带入中间包的熔渣和引流砂的严重污染。防止钢包渣和引流砂的卷入后,第一炉浇铸钢液的理论洁净度自始至终几乎是恒定的,而且比第二炉和第三炉的高。第二炉次的污染物量增加是因为引流砂被带入到中间包中。在第三炉次时,钢包中积累的熔渣和引流砂使钢液中污染物含量与第二次相当,它的洁净度变化也几乎与第二次相同。那么所得到的理论洁净度与实际洁净度的差值即中间包出口和入口之间的夹杂物上浮区的钢液污染物量。对氮的行为的单独研究表明,空气污染是中间包中钢液污染的一个重要因素。图3反应了空气污染和熔渣夹杂物对中间包钢液污染的影响。

图3 空气污染和熔渣夹杂物对中间包钢液污染的影响

空气污染对第一炉次到第二炉次中间包钢液污染影响很大,通过控制钢包熔渣和引流砂的带入量,第一炉次和第二炉次中间钢液中70%以上的污染物都可留在中间包内。随着浇铸炉次的增加,熔渣带入的污染物量增加,但是空气氧化造成的污染物量减少。这可能是因为中间包中积累的熔渣随着浇铸炉次的增加而增加,但是熔池表面被越来越多的熔渣覆盖,减少了空气对钢液的氧化。

上述结论表明,保持中间包中钢液纯净的方式有:(1)保护它免受空气污染;(2)使用无污染的钢包引流砂;(3)抑制钢包熔渣被带入到中间包中。本文讨论了第一和第二项工艺。抑制熔渣由钢包进入中间包的技术目前已经应用于工业并且取得了很好的效果[23]。

3 中间包钢液洁净技术

3.1 防止钢液被空气氧化

中间包一般用氩气排除空气以防止钢液被空气氧化。由于中间包无法完全密封以及中间包盖的扭曲变形,这项技术并不完善。前面章节所讨论的结果表明,增加中间包熔池表面的熔渣可以极大地防止钢液被空气氧化。因此在中间包熔池表面覆盖一种低熔点的可熔覆盖剂是防止钢液被空气氧化的方法之一。

3.1.1 实验室研究方法

在实验室实验中对中间包熔池表面覆盖剂的最优成分进行了研究。实验使用一个容量为100kg的高频熔炼炉熔炼70kg一定成分的铝镇静钢(0.038%C,0.012%Si,0.18%Mn,0.042%Al),入口处用氩气密封。然后在熔池表面投2.5kg 的覆盖剂,停止通入氩气,并且在钢液中投入金属铝,使钢液中铝的含量达到0.05%。在16分钟内每隔2分钟对钢液进行取样分析。实验室使用的中间包覆盖剂成分见表1。第一,试验每一种中间包覆盖剂对防止钢液被空气氧化的效果。第二,通过改变每种覆盖剂中SiO2的含量研究比铝亲和力稍小的SiO2对钢液氧化的影响;第三,用传统的含氧化镁98%的材料作为中间包的绝热材料。

表1 实验室使用的中间包覆盖剂成分

覆盖剂成分(%)

1 50CaO-50Al2O3

2 47.5CaO-47.5 Al2O3-5SiO2

3 45CaO-45 Al2O3-10SiO2

4 40CaO-40 Al2O3-20SiO2

5 100MgO(传统的热绝缘材料)

3.1.2 实验室实验结果

图4到6分别列出了在不同时间钢液中硅、氮、铝含量的变化。当使用传统的隔热材料(表1中5号)时,钢液会增氮。当在熔池表面使用可熔覆盖剂(表1中1,2,3,4号)时,钢液中氮的含量变化很小。所有的覆盖剂都可使钢中铝含量不同程度地降低。传统的隔热材料(表1中5号)和新的含10%以上SiO2的覆盖剂(表1中3,4号)都可以极大地降低钢中铝含量和显著地增加钢液被空气氧化的量。图6所示表明覆盖剂中硅含量为10%以上时会提高钢液中的硅含量。

图4 钢液中氮含量的变化

图5 钢液中铝含量的变化

图6 钢液中硅含量的变化

3.1.3 讨论

3.1.3.1 利用覆盖剂防止钢液被空气氧化

图4中氮含量的变化表明只有在使用传统隔热材料时钢液增氮。这意味着,传统的绝热材料对防止钢液被空气氧化的效果很小。因为传统的隔热材料中包含98%的氧化镁,也是耐火材料的主要成分,在中间包熔池表面将被直接烧结成浮石状,所以无法给钢液提供充分的保护以防止空气的渗入。

熔池表面覆盖的覆盖剂能很好的防止钢液增氮。钢液与外部空气之间形成的液态覆盖剂层可以很好的降低空气中氧进入钢液的速率。

3.1.3.2 SiO2含量对钢液氧化的影响

根据图5所示的铝含量的变化,钢液被空气氧化的量可以通过覆盖剂来控制,但是如果覆盖剂中SiO2的含量超过10%时(表1中3,4号),钢液中的铝含量将降低。

图6中硅含量的变化表明,当钢液覆盖剂中SiO2含量超过10%时,钢中硅含量会有所增加。根据这些实验结果可知,可熔覆盖剂可以防止钢液被空气污染,但是如果它含有SiO2或者其他比钢液中铝对氧的亲和力小的氧化物时,覆盖剂中的SiO2会和钢液中的铝反应氧化钢液。当覆盖剂中SiO2含量不高于5%时(表1中2号),不会导致钢液的氧化。当覆盖剂中SiO2含量超过10%时(表1中3,4号),钢液的氧化量会随着SiO2量的增加而增加。造成这种情况的可能原因是

SiO2的活度不同反应速率不同。上述结果表明,为了防止钢液的空气氧化和覆盖剂造成的钢液二次氧化,可以使用在钢液温度可以熔化的覆盖剂和不含或含有极少比钢液中铝对氧亲和度更小的成分的覆盖剂。

3.1.4 工厂实验结果

根据上一节实验室实验讨论得到的结果,在工厂实验中一个中间包内使用可熔覆盖剂。该工厂实验了连续浇铸三炉次的铝镇静钢(铝含量大约0.05%),实验所用中间包如图7所示。

图7 八幡厂1号连铸机的中间包示意图

可熔覆盖剂从中间包中心的堰和第一流左侧堰外之间的注流区加入。在第二流加入传统的含98%MgO的隔热材料。同时对中间包入口和出口的钢液进行取样。根据实验室试验结果,实验中使用的是CaO-Al2O3基的可熔覆盖剂。评估了组成为48CaO-37Al2O3-15MgO的覆盖剂(熔点为1530℃)对保护钢液免受空气氧化的效果,在1550℃的温度下其MgO在中间包钢液中达到饱和。图8所示为中间包内钢液总氧含量的变化。

图8 中间包内钢液总氧含量的变化

使用可熔覆盖剂时总氧含量为0.6ppm,使用不可熔覆盖剂时总氧含量为5.9ppm,这一发现证实了可熔覆盖剂对减少钢液中夹杂物形成的效果。

3.2 使用无污染的引流砂

在与钢液直接接触区域(顶层)和滑板区或不与钢液直接接触区域(底层)的钢包引流砂需具有不同的特性。顶层引流砂必须有良好的烧结性,以阻碍钢液渗透和固化成颗粒。底层的引流砂必须不容易烧结,以便滑动式水口打开时钢液可以顺利流出;为了使它不会上推其与钢液的接触面,引流砂必须有较小的膨胀系数。为了满足这种矛盾的特性,传统工艺采用一种主要成分为SiO2的引流砂作为适用材料。图9所示为近年来所采用的工艺[24],包括在顶层和底层使用不同成分的引流砂以保证滑动水口的自由打开,以及在顶层引流砂中添加R2O (R=Na,K)使其具有更好的烧结性能。而为了满足钢包内引流砂不污染中间包内钢液的要求,对引流砂基本成分进行研究的实验几乎没有。

图9 填充材料的方法

为了防止钢包引流砂污染钢液,本研究对上述的双层引流砂实验进行了扩充,研究了在提高滑动水口的自由开口性能的同时,保证钢液不被引流砂污染的要求。

3.2.1 实验室实验方法

在实验室实验中,首先对引流砂的物理性能进行了研究。在一个内径为57mm,高度为65mm的氧化铝坩埚中,加满引流砂样品,如图10所示。

图10 热膨胀系数的评价方法

分别在1000℃,1300℃,1500℃温度条件下对样品加热2小时,模拟滑动式水口处的温度分布情况,并对样品的烧结性能和热膨胀性进行了测试。将加热的引流砂试样冷却后,用手指触摸引流砂顶部并按表格2中所示的标准对其烧结性进行评估。

表2 烧结砂的评价标准

等级烧结条件

S-0 未烧结

S-1 轻微的烧结和容易被手指压塌

S-2 烧结和容易被手指压塌

S-3烧结和勉强被手指压塌

S-4 烧结和颗粒表面可以被手指刮下

S-5 完全烧结和玻璃化

将引流砂样品在1500℃加热2小时后,将坩埚切断。以坩埚顶部为基线,测量切割部分试样最大上升高度(+)或凹陷深度(—),引流砂样品的热膨胀性的计算公式如下:

热膨胀系数(%)

t (4)

=T

/?

100

其中:t为距坩埚顶部的最大上升高度或凹陷深度(mm),T为坩埚的高度(mm)。

本次实验室实验对五种不同的引流砂进行了研究:(1)在传统的双层体系顶部使用以SiO2为主的引流砂并添加R2O改善引流砂的烧结性能;(2)在双层系体系底部使用以高纯度SiO2为主的引流砂;(3)MgO基引流砂;(4)Al2O3-MgO

尖晶石基引流砂和Al2O3基引流砂。这些引流砂材料必须满足几乎不与钢液中的铝发生反应的条件,并且能够适用于工业生产。由于氧化钙很可能与钢渣或钢液中的铝反应生成低熔点化合物,极易烧结并且在贮藏过程中存在吸水和升华的问题,不适合用作引流砂材料,因此在本次评估试样中没有使用氧化钙。测试的样品中90%以上的颗粒尺寸都是1到2mm。坩埚是由氧化铝制成,其材质与滑动式水口的材质相近。检测材料的化学成分和晶粒分布见表3。

表3 喷嘴填料的化学成分和晶粒尺寸

样品号 1 2 3 4 5

材料低纯SiO2纯SiO2MgO 尖晶石Al2O3

化学成分(%)

SiO2 74 98 3 ——

Al2O3 13 1 —70 99 MgO ———28 —Ma2O+K2O 11 1 96 ——

粒度(%)

+2mm 5 — 1 ——

2-1 53 45 59 59 50

1-0.5 41 55 39 40 49

0.5- 1 — 1 1 1

将引流砂应用于双层体系并评估其性能。改变传统的单层引流砂操作中SiO2的含量,但是实验没有发现既可以满足顶层的烧结条件又可以满足底层不被烧结的条件的组分。因此进行了一次新的尝试,在双层体系中降低SiO2的比例,即在顶层使用传统的SiO2基引流砂以满足顶层对于良好烧结性能的需求,而在底层使用不含SiO2的引流砂。对在顶层使用能提高烧结性能的SiO2基引流砂(表3中1号)以及在底层使用不含SiO2的引流砂(表3中3,4,5号)的双层体系进行了测试。如图11所示,在一个氧化铝坩埚中的上下分别填充顶层引流砂和底层引流砂,在电阻炉中1500℃温度下加热2小时,研究:(1)从顶层到底层熔体成分之间的渗透以及顶层和底层之间反应区的厚度;(2)底层引流砂的烧结情况。待坩埚冷却后将其切断,在截口处测定反应区的厚度,并且根据表2中的标准评估底层引流砂的烧结性能。

图11 双层砂性能评价方法

3.2.2 实验室实验结果

表4所示为单层引流砂的评估结果。1号试样,即添加有可改善烧结性能的R2O和氧化铝的引流砂,加热到1300℃以上时,大部分都熔融形成一层玻璃烧结层。烧结层的形成可以防止钢液渗入引流砂中并防止钢液在引流砂中凝固。同时由于其烧结和熔化性能,1号试样体积也有所减小。2号试样,即由较纯的SiO2组成的引流砂,在加热到1500℃时,烧结性能达到S-3级,且热膨胀系数增加;样品3~5号,即含有很少或不含SiO2的引流砂,在实验过程中完全不烧结且热膨胀系数小。实验结果表明,含SiO2低的材料不能提供良好的烧结性能,不能单独用于引流砂。

表4单喷嘴过程填料的实验结果

样品号 1 2 3 4 5

材料低纯SiO2纯SiO2MgO 尖晶石Al2O3

烧结

1000℃×2h S-1 S-0 S-0 S-0 S-0 1200℃×2h S-5 S-0 S-0 S-0 S-0 1500℃×2h S-5 S-3 S-2 S-0 S-0

热膨胀(%)

1500℃×2h -25 30 0 0 0

表5所示为在顶层和底层分别使用烧结性能好的高纯度SiO2引流砂和低SiO2引流砂时,顶层和底层间反应区的厚度以及底层引流砂的烧结性能。

表5 双喷嘴过程填料的实验结果

顶层低纯SiO2低纯SiO2低纯SiO2低纯SiO2底层Si02 MgO 尖晶石Al2O3

反应区厚度(mm) 1040105

底砂的烧结S-3S-5S-0S-0

实验采用传统的双层体系,顶部引流砂完全烧结,底部引流砂半烧结到S-3级,顶层和底层之间形成了一个5mm厚的反应区。在底层引流砂中使用MgO 时,顶部和底部引流砂完全反应,熔化,并烧结,反应区的厚度为40mm,并且底部引流砂全部烧结到S-5级。从这些结果可以预测,如果在顶层使用SiO2基引流砂,在底层使用MgO基引流砂,钢包将无法自由打开。在底层使用Al2O3或尖晶石引流砂时,顶层与底层之间形成厚为5~10mm的反应区,且底部引流砂为S-0级的非烧结状态。这些结果表明,如果在顶层使用的是性能优良的SiO2引流砂时,可以在底层使用Al2O3和尖晶石引流砂。

3.2.3 讨论

在双层使用不同的引流砂时,顶层和底层之间厚反应区的形成与底层材料的烧结会降低滑动式水口引流砂的排放性能,导致在需要开启滑动式水口时水口无法自由打开。因此反应区域必须尽可能的薄以避免这种情况发生。实验室实验结果表明,如果在底层使用SiO2材料,那么可以在顶层使用Al2O3或尖晶石材料。反应区的厚度取决于底层引流砂的成分。反应区的形成机理将在下面进行讨论。

在传统的双层设计中顶层使用低纯度液相线温度为1000℃的SiO2基引流砂[25],当温度超过1500℃的铝镇静钢钢液被加入到钢包中,引流砂熔化,钢液渗入底层引流砂中并与其发生反应。底层使用的高纯度SiO2引流砂熔点超过1600℃。当渗透性好的顶层引流砂与底层引流砂反应时,将使SiO2含量及其熔点升高。当反应区的反应进行到一定程度时,顶部引流砂会停止向底部渗透。分别在顶部和底部使用MgO基引流砂和SiO2基引流砂,当滑动式水口和引流砂被钢包中的钢液加热后,顶部的MgO和底部的SiO2会发生反应。顶层引流砂因此

熔点降低并很快地渗透到底层引流砂中。如果在底层使用Al2O3或尖晶石,当顶层引流砂熔化并且渗入底部时,底层引流砂Al2O3的含量和熔点都会升高。因此,阻碍了顶部熔化的引流砂渗透到底层。上述结果表明,双层设计中顶部和底部引流砂最佳组合应该是这样的,在顶层的引流砂与钢液接触熔化,并渗透到底部与底层引流砂反应时,可以形成高熔点和高粘度的化合物。

3.2.4 工厂实验结果

基于实验室结果,将钢包引流砂应用于工厂试验。如图7所示,在八幡厂第3炼钢厂的1号连铸机上浇铸铝含量大约为0.05%的铝镇静钢。在使用了新的钢包引流砂后,研究了钢包的自由开口性能以及阻碍中间包中钢液污染的性能。为了消除钢液在浇铸开始由钢包注入中间包时被空气氧化的影响以及防止在一炉浇铸结束时钢液被钢包带入中间包中的熔渣污染,两炉连续浇铸,且在第一炉浇铸时留20吨钢液在钢包中,以保证熔渣不会被带入到中间包中。

第二炉浇铸时在中间包塞棒处距熔池表面400mm处用快冷取样器对钢液取样,每隔1到10分钟取一次样。在离样品底部100mm处将试样切断,抛光,并在光学显微镜下观察和统计10μm以上的夹杂物形状(簇状,丛状,或球状)和大小。

图12显示了在使用这种类型的引流砂后钢包自由开口性能的变化。钢包使用不含SiO2基引流砂时其自由开口性能与使用传统的SiO2基引流砂相同。在使用了这种引流砂后,从钢包浇注开始,中间包中氧化铝夹杂物含量的变化如图13所示。使用传统的SiO2基引流砂时,在钢包刚开始浇注5分钟后中间包中氧化铝夹杂物的量开始增加。新的不含SiO2基引流砂可以成功阻止中间包中氧化铝夹杂物量的增加。

图12 使用不含SiO2的引流砂时钢包自由开口性能的变化

图13 使用新型的引流砂对钢液中氧化铝含量的影响

4 结论

为了以稳定的方式实现高清洁度钢液的工业化生产,本文通过研究中间包内钢液洁净度,对钢液在中间包内被污染的影响因素进行了定量分析。实验采用了各种工艺以进一步确定其影响因子。结果如下:

(1)中间包中钢液主要是被空气氧化以及引流砂污染。

(2)随着浇铸炉次的增加,钢液被空气氧化影响降低,但是由钢包引流砂带入中间包钢液中的夹渣增加了。

(3)如果在熔池表面使用在钢液温度下可熔且不含可与钢液中铝发生反应的覆盖剂,中间包中的钢液能很好地被保护不被空气氧化。

(4)在钢包中使用双层结构或顶底层体系引流砂,并在底层使用不含SiO2的引流砂,这样既可以保证钢包的自由开口性能,也可以保护钢液免受污染。

(5)必须保证双层设计的底层引流砂在滑动水口的温度下不被烧结,并且保证在顶层引流砂与钢液接触熔化,并渗透到底部与底层引流砂反应时,可以形成高熔点和高粘度的化合物。如果在顶层使用SiO2基引流砂,那么可以在底层使用Al2O3或MgO-Al2O3尖晶石引流砂。

术语:

A:夹杂物的面积分数(—)

inc

D:夹杂物的粒径(um)

pi

Ni:不同大小夹杂的数量(—)

N:中间包中钢液受污染的总量(—)

p

S:光学显微镜的监测面积(m2)

V:夹杂物的体积分数(—)

inc

W:夹杂物的质量分数(—)

inc

α:氧化铝团簇中氧化铝的体积比(—)

α:不同大小夹杂物的上浮率(—)

i

ρ:钢液的密度(=7000)(kg/m3)

Fe

ρ:夹杂物的密度(=3600) (kg/m3)

inc

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Interaction design Moggridge Bill Interaction design,Page 1-15 USA Art Press, 2008 Interaction design (IxD) is the study of devices with which a user can interact, in particular computer users. The practice typically centers on "embedding information technology into the ambient social complexities of the physical world."[1] It can also apply to other types of non-electronic products and services, and even organizations. Interaction design defines the behavior (the "interaction") of an artifact or system in response to its users. Malcolm McCullough has written, "As a consequence of pervasive computing, interaction design is poised to become one of the main liberal arts of the twenty-first century." Certain basic principles of cognitive psychology provide grounding for interaction design. These include mental models, mapping, interface metaphors, and affordances. Many of these are laid out in Donald Norman's influential book The Psychology of Everyday Things. As technologies are often overly complex for their intended target audience, interaction design aims to minimize the learning curve and to increase accuracy and efficiency of a task without diminishing usefulness. The objective is to reduce frustration and increase user productivity and satisfaction. Interaction design attempts to improve the usability and experience of the product, by first researching and understanding certain users' needs and then designing to meet and exceed them. (Figuring out who needs to use it, and how those people would like to use it.) Only by involving users who will use a product or system on a regular basis will designers be able to properly tailor and maximize usability. Involving real users, designers gain the ability to better understand user goals and experiences. (see also: User-centered design) There are also positive side effects which include enhanced system capability awareness and user ownership. It is important that the user be aware of system capabilities from an early stage so that expectations regarding functionality are both realistic and properly understood. Also, users who have been active participants in a product's development are more likely to feel a sense of ownership, thus increasing overall satisfa. Instructional design is a goal-oriented, user-centric approach to creating training and education software or written materials. Interaction design and instructional design both rely on cognitive psychology theories to focus on how users will interact with software. They both take an in-depth approach to analyzing the user's needs and goals. A needs analysis is often performed in both disciplines. Both, approach the design from the user's perspective. Both, involve gathering feedback from users, and making revisions until the product or service has been found to be effective. (Summative / formative evaluations) In many ways, instructional

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Journal of Industrial Textiles https://www.sodocs.net/doc/9d543431.html,/ Optimization of Parameters for the Production of Needlepunched Nonwoven Geotextiles Amit Rawal, Subhash Anand and Tahir Shah 2008 37: 341Journal of Industrial Textiles DOI: 10.1177/1528083707081594 The online version of this article can be found at: https://www.sodocs.net/doc/9d543431.html,/content/37/4/341 Published by: https://www.sodocs.net/doc/9d543431.html, can be found at:Journal of Industrial TextilesAdditional services and information for https://www.sodocs.net/doc/9d543431.html,/cgi/alertsEmail Alerts: https://www.sodocs.net/doc/9d543431.html,/subscriptionsSubscriptions: https://www.sodocs.net/doc/9d543431.html,/journalsReprints.navReprints: https://www.sodocs.net/doc/9d543431.html,/journalsPermissions.navPermissions: https://www.sodocs.net/doc/9d543431.html,/content/37/4/341.refs.htmlCitations: - Mar 28, 2008Version of Record >>

国际贸易英文文献

Strategic transformations in Danish and Swedish big business in an era of globalisation, 1973-2008 The Danish and Swedish context In the difficult inter-war period, a state-supported, protected home market orientation had helped stabilise both Denmark’s and Sweden’s economies, but after WorldWar II priorities changed. Gradually and in accordance with the international economic development, restrictions on foreign trade were removed, and Danish and Swedish industry was exposed to international competition. As a consequence, several home market oriented industries –such as the textile and the shoe industry –were more or less outperformed, while in Sweden the engineering industry soon became the dominant leader of Swedish industry, with companies such as V olvo, Ericsson, Electrolux, ASEA and SKF. In the Danish case, the SMEs continued to be dominant but in combination with expanding export oriented industrial manufacturers such as Lego, Danfoss, Carlsberg and the shipping conglomerates ok and A.P. moller-Marsk. In Sweden and Denmark stable economic growth continued into the 1970s, but due to the problems during the oil crises, the economies came into fundamental structural troubles for the first time since World War II. In the beginning this was counteracted by traditional Keynesian policy measures. However, because of large budget deficits, inflation and increasing wages, both the Danish economy from 1974 and the Swedish economy from 1976 encountered severe problems. Towards the late 1970s Denmark’s and Sweden’s economic policies were thus increasingly questioned. It was clear that Keynesian policy could not solve all economic problems. Expansive fiscal policies in terms of continued deficits on the state budget could not compensate for the loss of both national and international markets and step by step the Keynesian economic policy was abandoned. The increased budget deficit also made it difficult for the state to support employment and regional development. These kinds of heavy governmental activities were also hardly acceptable under the more market oriented policy that developed first in Great Britain and the USA, but in the 1980s also in Denmark and Sweden (Iversen & Andersen, 2008, pp. 313–315; Sjo¨ gren, 2008, pp. 46–54). These changes in political priorities were especially noticeable in the financial market. After being the most state regulated and coordinated sector of the economy since the 1950s, then between 1980 and 1985 the Danish and Swedish financial markets underwent an extensive deregulation resulting in increased competition. Lending from banks and other credit institutes was no longer regulated, and neither were interest rates. The bond market was also opened as the issuance of new bond loans was deregulated in Sweden in 1983. When the control of foreign capital flows was liberalised in the late 1980s the last extraordinary restriction was now gone. Together with the establishment of the new money market with options and derivates, this opened up to a much larger credit market and the possibility for companies to finance investments and increase business domestically as well as abroad (Larsson, 1998, pp. 205–207). Another important part of the regulatory changes in the early 1980s were new rules for the Copenhagen and Stockholm stock exchanges. Introduction on the stock exchange was made much

工业设计产品设计中英文对照外文翻译文献

(文档含英文原文和中文翻译) 中英文翻译原文:

DESIGN and ENVIRONMENT Product design is the principal part and kernel of industrial design. Product design gives uses pleasure. A good design can bring hope and create new lifestyle to human. In spscificity,products are only outcomes of factory such as mechanical and electrical products,costume and so on.In generality,anything,whatever it is tangibile or intangible,that can be provided for a market,can be weighed with value by customers, and can satisfy a need or desire,can be entiled as products. Innovative design has come into human life. It makes product looking brand-new and brings new aesthetic feeling and attraction that are different from traditional products. Enterprose tend to renovate idea of product design because of change of consumer's lifestyle , emphasis on individuation and self-expression,market competition and requirement of individuation of product. Product design includes factors of society ,economy, techology and leterae humaniores. Tasks of product design includes styling, color, face processing and selection of material and optimization of human-machine interface. Design is a kind of thinking of lifestyle.Product and design conception can guide human lifestyle . In reverse , lifestyle also manipulates orientation and development of product from thinking layer.

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毕业论文外文文献翻译 毕业设计(论文)题目关于企业内部环境绩效审计的研究翻译题目最高审计机关的环境审计活动 学院会计学院 专业会计学 姓名张军芳 班级09020615 学号09027927 指导教师何瑞雄

最高审计机关的环境审计活动 1最高审计机关越来越多的活跃在环境审计领域。特别是1993-1996年期间,工作组已检测到环境审计活动坚定的数量增长。首先,越来越多的最高审计机关已经活跃在这个领域。其次是积极的最高审计机关,甚至变得更加活跃:他们分配较大部分的审计资源给这类工作,同时出版更多环保审计报告。表1显示了平均数字。然而,这里是机构间差异较大。例如,环境报告的数量变化,每个审计机关从1到36份报告不等。 1996-1999年期间,结果是不那么容易诠释。第一,活跃在环境审计领域的最高审计机关数量并没有太大变化。“活性基团”的组成没有保持相同的:一些最高审计机关进入,而其他最高审计机关离开了团队。环境审计花费的时间量略有增加。二,但是,审计报告数量略有下降,1996年和1999年之间。这些数字可能反映了从量到质的转变。这个信号解释了在过去三年从规律性审计到绩效审计的转变(1994-1996年,20%的规律性审计和44%绩效审计;1997-1999:16%规律性审计和绩效审计54%)。在一般情况下,绩效审计需要更多的资源。我们必须认识到审计的范围可能急剧变化。在将来,再将来开发一些其他方式去测算人们工作量而不是计算通过花费的时间和发表的报告会是很有趣的。 在2000年,有62个响应了最高审计机关并向工作组提供了更详细的关于他们自1997年以来公布的工作信息。在1997-1999年,这62个最高审计机关公布的560个环境审计报告。当然,这些报告反映了一个庞大的身躯,可用于其他机构的经验。环境审计报告的参考书目可在网站上的最高审计机关国际组织的工作组看到。这里这个信息是用来给最高审计机关的审计工作的内容更多一些洞察。 自1997年以来,少数环境审计是规律性审计(560篇报告中有87篇,占16%)。大多数审计绩效审计(560篇报告中有304篇,占54%),或组合的规律性和绩效审计(560篇报告中有169篇,占30%)。如前文所述,绩效审计是一个广泛的概念。在实践中,绩效审计往往集中于环保计划的实施(560篇报告中有264篇,占47%),符合国家环保法律,法规的,由政府部门,部委和/或其他机构的任务给访问(560篇报告中有212篇,占38%)。此外,审计经常被列入政府的环境管理系统(560篇报告中有156篇,占28%)。下面的元素得到了关注审计报告:影响或影响现有的国家环境计划非环保项目对环境的影响;环境政策;由政府遵守国际义务和承诺的10%至20%。许多绩效审计包括以上提到的要素之一。 1本文译自:S. Van Leeuwen.(2004).’’Developments in Environmental Auditing by Supreme Audit Institutions’’ Environmental Management Vol. 33, No. 2, pp. 163–1721

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