共查询到20条相似文献，搜索用时 62 毫秒
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2008年,我国水泥产量接近14亿吨,占世界水泥产量的1/2;水泥工业对石灰石、煤炭、电力等资源、能源的消耗,以及形成的工业粉尘、CO2、SO3、NOx等大气污染物,给自然界带来巨大的环境负荷.自2009年哥本哈根联合国气候变化会议召开以来,"低碳'的环保意义人尽皆知,"绿色、低碳水泥"将是未来水泥生产的发展之路.笔者从提高水泥中的混合材掺加量降低水泥熟料使用量角度讨论绿色低碳水泥生产. 相似文献
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为了研究粉煤灰碎石材料的疲劳性能.分别对石灰粉煤灰碎石、水泥粉煤灰碎石、水泥稳定碎石材料进行疲劳试验.结果表明,石灰粉煤灰碎石的抗疲劳性能最好,其次是水泥粉煤灰,水泥稳定碎石抗疲劳性能较差.在施工中,建议在满足强度的情况下,尽量使用石灰粉煤灰碎石. 相似文献
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为了提高水泥胶砂的力学性能,提出在水泥胶砂中掺加外加剂的方法,通过在水泥胶砂中单掺引气剂、复掺引气剂与减水剂两种途径,进行水泥胶砂抗折强度检测试验,对比确定水泥胶砂力学性能最优的引气剂型号及其最佳掺量.结果表明:引气剂与减水剂复掺时水泥胶砂的抗折强度明显大于引气剂单掺时水泥胶砂的抗折强度,2#引气剂最能满足水泥胶砂抗折强度要求. 相似文献
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杨守华 《连云港职业技术学院学报》1996,(3)
水泥是一种主要建筑材料,它在我国国民经济建设中发挥重要作用.随着我国经济建设的快速发展,水泥用量也与日俱增,因而我国小水泥工业发展也很迅速,全国小水泥产量占全国水泥总产量的三分之二以上,它已成为我国基本建设特别农业建设.人防建设的主要材料之一.这是我国水泥工业的特点,但是,由于小水泥生产条件参差不齐,质量差别较大,有的质量较好,有的质量较差.因此,使用部门从保证工程质量角度出发,作出了有关规定.例如:有的地方规定小水泥不准用于砼工程,仅准用于抹灰,砌筑,素砼工程;有的地方采取增加水泥用量的方法.其目的就是为了保证工程质量. 相似文献
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随着现代汽车载重量与行车速度的不断增加,水泥混凝土路面结构得到了广泛的应用.随着我国水泥混凝土路面工程建设项目的不断增加,水泥混凝土路面常见病害的防治也提到了施工企业管理工作的日程中.如何加强水泥混凝土路面病害的防治成为了现代公路建设与养护企业面临的首要问题.本文就水泥混凝土公路施工过程中路面病害的防治进行了简要论速. 相似文献
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一、选择题
1.跳远时,跳在洮坑里比跳在水泥地上安全,这是由于( )
A.人跳在沙坑的动量比跳在水泥地上小
B.人跳在沙坑的动量变化比跳在水泥地上小
C.人跳在沙坑受到的冲力比跳在水泥地上小
D.人跳在沙坑受到的冲量比跳在水泥地上小 相似文献
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水泥机立窑的烟尘排放是水泥生产中对环境的最大污染,其除尘技术是解决问题的关键.介绍了国内目前现有的几种水泥机立窑的除尘技术,对水泥行业当中常用除尘技术进行了归纳比较,以便工程方案设计优化,为今后的除尘技术发展提供帮助. 相似文献
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以粉煤灰、低品位石灰石、分析纯氧化镁和硅酸盐水泥生料为原料,在实验室YFX 16Q-YC高温箱式电阻炉的不同温度条件下进行Q相水泥熟料和硅酸盐水泥熟料的煅烧制备.对试验获得的Q相水泥熟料样品进行了矿物组成X射衍射(XRD)、扫描电子显微镜(SEM)和能谱(EDS)图谱分析,对试验获得的Q相水泥熟料和硅酸盐水泥熟料进行了游离氧化钙f-CaO质量分数测定比较.结果表明:以粉煤灰和低品位石灰石为主要原料,在1320℃可煅烧出合格的Q相水泥熟料,在1320℃温度条件下,Q相水泥熟料样品和硅酸盐水泥熟料样品的游离氧化钙f-CaO分别为1.29%和5.65%;粉煤灰和低品位石灰石配料制备Q相水泥熟料,较传统硅酸盐水泥熟料的制备,其生料易烧性得到较大改善;粉煤灰和低品位石灰石配料制备Q相水泥熟料,其煅烧温度较传统硅酸盐水泥熟料煅烧温度约降低80～130℃. 相似文献
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我国水泥市场呈现明显的区域性发展特征.在长江三角洲、珠江三角洲和环渤海地区是我国水泥市场生产量较高、生产力较强、市场发育较为成熟的区域.水泥市场的发展与省域投资额度、区域经济增长、区域人口总量呈显著的正相关关系. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献