共查询到20条相似文献，搜索用时 15 毫秒
1.
高天秀 《淮南职业技术学院学报》2014,(3):10-14
煤沥青是煤炭经高温热分解后的副产物煤焦油经进一步蒸馏加工后的产物,煤沥青组成极为复杂,具有稳定的性能,以煤沥青为原料,经过进一步加工后可获得一系列重要的高附加值衍生产品;综述了煤沥青用作煤沥青涂料、筑路沥青、炭素工业浸渍剂和粘结剂以及中间相煤沥青等方面的应用原理和进展。 相似文献
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孙幼红 《南京晓庄学院学报》2011,(6):58-60
文章介绍了煤焦油与聚氯乙烯共混改性的方法,探讨了聚氯乙烯与增塑剂用量对共混物性能的影响;本文同时给出了利用膨润土将聚氯乙烯-煤焦油共混物分散于水中制备水性涂料的方法,并对该涂料性能进行了测试．测试结果表明,除断裂伸长率较低外,该涂料与水乳型沥青防水涂料性能类似,考虑到该涂料优异的低温柔性能够补充断裂伸长率的不足,可以做出该涂料满足防水要求的结论． 相似文献
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洛川（甘杰村）方言的四个调类在调值上表现为“平声（阴平、阳平）低,上去高”.蟹摄开口一二等、合口二等（多数）,以及效摄的韵母依据调值的高低分化为两类：蟹摄平声为[ε]类,上去为[εe]类;效摄平声为[（o）]类,上去为[（o）o]类,遵循“低调低舌位、单韵母,高调高舌位、复韵母”的规律. 相似文献
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To improve the processing efficiency and the quality of orbital milling hole of aerospace Al-alloy, the big-pitch influence on cutting force and hole quality was studied experimentally. First, a program based on horizontal lathe was proposed based on kinematics analysis of orbital milling. Then, the cutting force at different stages and the hole quality with different pitches were measured. Results show that the axial force and radial force increase with the pitch amplification during orbital milling. However, the axial force in the orbital milling hole is about 8—10 times smaller than that in the conventional drilling. The diameter error of milling hole is 48—93 μm, and the surface roughness of milling hole is 1.2—1.7 μm. Finally, an orbital milling device with big pitch was designed. 相似文献
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The coal tar was qualitative and quantitative anMyzed by gas chromatography （GC） method. 74 components were identified exactly by gas chromatographY-mass spectrometry （GC-MS）. 31 components （37%） were quantitatively analyzed by gas chromatography-flame ionization detector （GC-FID）. The linearity, accuracy, precision, limit of detection （LOD） and limit of quantitative （LOQ） determination were inspected. The scope of quantitative analysis by CC was discussed. The experimental results of thermogravimetric analysis （TGA） proved that GC quantitative analysis of the coal tar was reliable. 相似文献
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通过对2个云杉八齿小蠹伴生蓝变真菌的试验研究,结果表明：2个蓝变菌菌株适宜生长温度均为25℃;对酸碱度的适应能力强,在pH4．0～9．0范围内均能生长,在酸性环境下发育较好;以葡萄糖和果糖为最佳碳源,最佳氮源为甘氨酸,此外菌株Ophiostoma penicillatum 1也可很好利用酵母粉．甲基托布津、扑海因对2个试验菌株的生长有极强的抑制效果,百菌清和中生菌素仅对Ophiostoma penicillatum 2有很强的抑制效果,可杀得和硫酸链霉素对所有菌株的抑制作用均不明显． 相似文献
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数字图像分析方法在螺纹检测中的应用 总被引：3，自引：0，他引：3
This paper describes the use of computer-aided measurement for external metric screw threads.Thread parameters,including thread pitch,thread angle,pitch giameter and major diameter,were measured with CCD cameras and image analysis software.New technologies such as digital image processing were used to increase the efficiency of measurements.In this study,by reconstructing the toolmaker‘s microscope,the computer-aided semi-automated measuring system was developed,which could evaluate the accuracy of screw thread fpofile.It is concluded that the measuement accuracy is comparable to that of traditional toolmaker‘s microscope method. 相似文献
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利用PECVD生长技术制备a-Si/SiNx多层膜,利用解理技术获得干净平滑的截面.利用选择性化学腐蚀技术在横截面上制备出浮雕型一维纳米模板.通过控制多层膜子层的生长时间,得到线条宽度和槽状宽度均最小为20纳米的等间距模板,品质优于电子束制备的模板.以这种模板为基础,利用印章技术制作了硅基光栅. 相似文献
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High-temperature coal tar was extracted with petroleum ether(PE) under ultrasonic irradiation and the extracts were analyzed with gas chromatograph/mass spectrometer.The acearylene fractions including acenaphthylene,aceanthrylene and cyclopentapyrene were enriched together and named E,which was then transferred to a cartridge in Isolera-One flash chromatography.Three groups of compounds were eluted out with ethyl acetate/PE mixed solvent(volume ratio 1:9) and named E 1,E 2 and E 3 according to their main components.Acenaphthylene accounted for 78.2% in E 1,aceanthrylene 71.6% in E 2 and cyclopentapyrene 75.9% in E 3,respectively.The three groups of acearylenes were purified by Sephadex LH-20 column chromatography with ethanol/cyclohexane mixed solvent(volume ratio 1:4),and then confirmed with nuclear magnetic resonance spectrometer.This method indicates that flash chromatography has a good effect on separating the compounds with a similar structure after extraction under ultrasonic irradiation. 相似文献
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南美蟛蜞菊在煤矿废弃地的栽培与应用研究 总被引：1，自引：0，他引：1
本研究以南美蟛蜞菊Wedelia trilobata为实验材料,选择煤矸石土进行栽培试验研究,选择普通有机土作对照,在栽培期间定期对南美蟛蜞菊的鲜重、生长速度、新芽数、新叶数、叶色等指标进行观察测定。实验结果表明：南美蟛蜞菊在煤矸石土生长40d时叶色深绿;新增茎节数与有机土植株之比为31：48,新叶数与有机土植株之比为96：182,生物量（鲜重）没有出现显著差异。说明南美蟛蜞菊在煤矸石土栽培有良好的生长适应性。适宜用于煤矸石土植被恢复和重建材料． 相似文献
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栀子炒炭前后栀子苷含量分析 总被引：2，自引：0，他引：2
利用紫外分光光度法和薄层色谱法，研究了生炭栀子中栀子苷含量的变化，通过试验证明栀子止血的有效成分与栀子苷无关,本法操作简单设备易得，便于推广． 相似文献
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Garrill A 《CBE life sciences education》2011,10(4):430-435
This article describes an undergraduate lab exercise that demonstrates the importance of students thinking critically about what they see through a microscope. The students are given growth data from tip-growing organisms that suggest the cells grow in a pulsatile manner. The students then critique this data in several exercises that incorporate aspects of a problem-based learning approach, envisaging growth not just in two dimensions, but in three dimensions. For some cells, what appears to be pulsatile growth could also be explained by growth at a constant rate up and down in the z-axis. Depending on the diffraction pattern generated by the tip of the cell, this movement in the z-axis could go undetected. This raises the possibility that pulsatile growth seen in some species may be an artifact generated by the limitations of the light microscope. Students were subsequently asked to rate their awareness of the need to think critically about what they see through a microscope, using a scale of 1 (unaware) to 5 (very much aware). Prior to doing the lab exercise, the mean rating was 2.7; this increased to 4.4 after the lab. The students also indicated a likelihood of being more critical in their thinking in other aspects of their biology curriculum. 相似文献
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张绍斌 《洛阳工业高等专科学校学报》2007,17(5):13-14
由于熔窑的长期运行以及燃料由重油改为煤焦油,从而造成了部分蓄热室的严重堵塞,严重影响熔窑的熔化作业,影响玻璃的产量和质量.为此,通过制定详尽的热修计划,合理的止火降温方案及科学的施工,对1号3号两对窑炉蓄热室进行了整体格子砖的热修,收到了好的效果. 相似文献
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This study aims to understand how faculty identity development is related to a differential use of writing genres in the teaching and research spheres of activity and whether this development follows different paths, on the bases of faculty perceptions regarding what they consider their main goal at university and their preferred sphere of activity. Participants (N?=?67) answered the online survey Faculty identity and academic writing. A mixed-method design combining quantitative and qualitative data analysis was used. Results showed first that the most often used genres were written exams in the teaching sphere of activity. Second, activities related to the research sphere, such as writing-related activities and participation in events were the least reported while evaluative activities were mentioned in all spheres. Third, faculty’s perceptions regarding their main goal at university (research) were not in alignment with their preferences (teaching). Writing genres used and activities reported closely mirror preferred spheres of activity and mismatch faculty’s perceptions of their main goal at universities. In conclusion, sphere of activity preferences relate to different paths of faculty’s identity development. 相似文献
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在云南省低纬高原气候下,将3个不同原产地的12个烤烟资源进行种植,采用多元统计的方法,分析其生物学性状.结果表明,根据其生物学性状的差异初步可分为Ⅰ,Ⅱ两个大类.美国引进与云南自育的烤烟种质资源同属第Ⅰ类,又包括I1,I2两个亚类.两个亚类相比,主要差异表现在生育期的不同,株高、茎围和叶长仅从平均值的对比上有差异,而叶数、节距和长宽比则几乎没有差异.从生育期来看,与Ⅰ1亚类相比,第Ⅰ2亚类（包括GL939和RGH4）表现为,大田移栽至烟株各个生育期均有提前,移栽至团棵提前1-2 d,现蕾期以后每个生育时期都提前8-12 d,整个大田生育期提前约8 d.津巴布韦引进烤烟种质资源属于第Ⅱ类,其生育期表现为大田移栽至烟株生长的各个时期均较晚,团棵期推迟1-2 d,现蕾期以后每个生育时期均推迟10-15 d,整个大田生育期推迟10-15 d.其农艺性状表现为高秆、多叶、节距稀,叶片呈椭圆形. 相似文献
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和声搜索算法是最近提出的一种基于乐队和声调谐原理的新搜索算法,目前已经有许多成功的应用。针对和声退火算法的不足,通过简化退火降温方式和终止条件,以及采用模拟退火算法修改和声库中最差解的更换方式,提出了一种改进的和声退火算法,数值实验表明了改进的和声退火算法的有效性和优越性。 相似文献
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包容性绿色增长是一种新的发展方式,要求在经济高质量增长的同时更多地关注社会问题和环境问题,实现经济、社会和环境协调发展。采集2000—2016年安徽省地级市数据,多维度选取指标体系,使用熵权法对包容性绿色增长进行了综合测度。研究表明,安徽省包容性绿色增长指数变化平稳,围绕均值小幅度波动;地区内部以及地区之间经济增长指数、社会公平指数、民生福利指数、绿色生产指数以及环境保护指数差距较大,发展不平衡不充分问题比较突出。教育水平和产业结构合理化程度对包容性绿色增长具有积极的促进作用,而经济制度变迁和城镇化对包容性绿色增长具有一定的抑制作用。 相似文献
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Vivienne Griffiths 《International Journal of Inclusive Education》2013,17(3):267-285
This paper presents a comparative study of two groups of student mothers from a teacher training course in the UK at the start and end of the 1990s, with a focus on gender issues. The study investigated the extent to which the women students could draw on their experiences as mothers to positive effect in their training, combining public and private spheres, and how far their domestic responsibilities created problems for them on the course. All the women possessed considerable skills, particularly in working with children, which were an attribute in their training. Although both groups faced similar difficulties, such as the double burden of domestic and course work, and changes in family life arising from their status transition, it was found that the more recent students could cross the boundaries between public and private roles more quickly and easily than those at the start of the 1990s. This was partly because the recent group had greater prior work experience and had already negotiated boundaries between private and public identities, and partly because some structural constraints had diminished by the end of the decade, at least at a local level. It is also argued that, although pressures on trainee teachers in general intensified during the 1990s, some effects of the changes were beneficial to student mothers. The findings are analysed within the dual frameworks of gender in higher education and initial teacher education. 相似文献