共查询到20条相似文献，搜索用时 125 毫秒
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吴伟 《淮南职业技术学院学报》2015,(3):1-6
深孔预裂爆破增透主要是利用炸药爆炸时产生的强烈的应力波和爆生气体对低透煤层的破碎作用,加大低透煤层的裂隙,以增加瓦斯的解吸量和煤层的透气性,提高抽采效率,为了取得更好的爆破破裂效果,对爆破工艺进行了优化;通过实践对比,深孔预裂爆破可以很好的解决低透煤层石门揭煤抽采半径小、抽采浓度低、抽采时间长等问题,大大提高了石门揭煤的安全性。 相似文献
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刘立华 《唐山师范学院学报》2008,30(2):59-61
系统阐述了纳米氧化锌的各种制备方法、反应原理及应用研究状况.介绍了纳米氧化锌在紫外线屏蔽、抗菌除臭、橡胶工业、涂料工业等方面的应用及它作为光催化材料、气敏、压电材料、吸波材料等的独特性能,并对其广阔的应用前景进行了展望. 相似文献
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在进行演示实验"渗透作用与水分的流动"时两个条件决定了实验的成败: 一、半透膜的选择;二、半透膜两侧的溶液具有适当的浓度差.在两个条件中起到关键的作用的是半透膜的选择,而在日常生活中可以作为半透膜的材料有很多,那么如何选择就具有一定的难度,下面就对常见半透膜进行分析. 相似文献
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在橡胶籽苗的三个不同物候期对其外施乙烯利,研究不同敏感性橡胶籽苗外施乙烯利后的质膜透性和膜脂过氧化的变化结果,为用乙烯利选择优良砧木提供理论依据.结果表明:材料1质膜透性极显著地高于材料2,膜脂过氧化程度二者差异不显著;材料 4膜脂过氧化程度极显著高于材料3,质膜透性二者差异不显著;材料5质膜透性极显著地高于材料6,膜脂过氧化二者差异不显著. 相似文献
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透氢膜材料由于在氢分离方面的广泛应用而备受关注.介绍了目前研究较多的 Pd 及其合金透氢膜和质子-电子混合导体透氢膜,重点综述了高温混合导体透氢膜的发展近况,对其发展前景和方向进行了展望. 相似文献
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《淮北师范大学学报》2016,(4)
利用开放实验平台,设计水热/溶剂热合成微纳米吸波材料开放实验.研究实验参数对微纳米吸波材料形成过程和吸波性能的影响.实验的开设能进一步扩大学生的知识面,提高学生的综合能力,有利于创新型人才培养. 相似文献
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前不久同济大学波耳固体物理研究所王珏、沈军主持的课题组的上海市科委两个重点项目“新型纳米复合变色防伪材料的研制”和“显示系统的新型宽带光学增透技术”又取得新的突破,连续通过专 相似文献
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目的:自反应淬熄法制备的LiZn铁氧体空心微珠密度小,低频吸波性能良好,但微珠表面晶型生长不充分。对其采用特定热处理工艺不仅可以使晶体充分发育,获得特定晶型,还可以实现对低频吸波性能的有效调控。本文旨在研究热处理工艺对LiZn铁氧体空心微珠表面形貌、相结构和低频吸波性能的影响。创新点:1.通过热处理工艺,实现对LiZn铁氧体空心微珠表面形貌、相结构和低频吸波性能的有效调控;2.深入分析热处理工艺对LiZn铁氧体空心微珠低频吸波性能的改善机理。方法:1.通过工艺探索,确定热处理的详细工艺参数。2.通过扫描电子显微镜检测和X射线衍射分析,获得热处理前后LiZn铁氧体空心微珠的微观形貌(图2)和物相组成(图3)。3.通过矢量网络分析仪,获得热处理前后材料的电磁参数(图4);在此基础上对比其吸波性能(图5),并研究吸波影响机理。结论:1.采用240°C/min升温至1200°C并保温4 h的热处理后,LiZn铁氧体空心微珠表面晶粒明显长大;2.热处理后,微珠四个电磁参数均有所增大,低频吸波性能明显提高,吸收峰值向低频移动;3.表面多种形状微纳米晶粒的形成和长大可能是LiZn铁氧体空心微珠低频吸波性能得以提高的主要原因。 相似文献
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姜兵 《牡丹江教育学院学报》2004,(4)
皮革的透水汽性能,是指皮革让水蒸气由湿度较大的空气中透到湿度较小的空气中的能力。它的定义为:试样在单位面积时间内所透过的水蒸气量。其结果用“毫克/10平方厘米24小时”来表示。因为皮革具有现今一切合成材料所不及的透水汽性能,能排除穿用者身体上的汗气,使穿用者感到舒服,所以天然皮革制品一直深受广大消费者的青睐。作为衡量皮革产品卫生性能的一项重要指标,准确地对皮革的 相似文献
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合成了一系列Eu^3 (Tb^3 )和phen共掺杂的杂化材料，并对其发光性能进行了考察。在所有样品中除了掺杂浓度为1％的样品外，其余材料均为透明块状且无裂纹。所有材料在紫外灯照射下，发出明亮的红光（Eu^3 掺杂）和绿光（Tb^3＋掺杂）。 相似文献
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将CCD测试技术引入物理实验,介绍了依据折射定律设计的能够测量任何透明介质折射率的仪器原理、使用方法及开设的部分实验内容,给出了对一些材料折射率的测量结果。 相似文献
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玻璃以其晶莹多样、简洁明快等特有的特色和魅力深受大众消费者的喜爱,在室内装修中占有独特的地位。本文利用3dsmax阐述几种玻璃材质的制作,以提高学生对材质的进一步认识和应用。 相似文献
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浅议做好高校的政府采购工作 总被引：5，自引：8，他引：5
谢海军 《实验室研究与探索》2004,23(11):110-112
实行教学仪器设备的政府采购，规范物资采购行为，增加决策的透明度，提高资金的使用效率，防止腐败现象发生。 相似文献
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Word frequency effects in naming for experienced and previously experienced adult readers of Persian
Bahman Baluch 《Reading and writing》1996,8(5):433-441
In a word naming experiment, experienced readers of Persian named high frequency transparent Persian words significantly faster than matched low frequency words. There was no such frequency effect for adults who had, during the past decade or more, very little experience in reading materials in Persian due to immigration to the West. Overall, the previously experienced adults named words significantly slower than their experienced counterparts. The implications of this finding in relation to models of visual word recognition are discussed. 相似文献
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The phonologically transparent Persian orthography is normally transcribed with two distinct spellings; words spelled with
vowels (letters) transcribed as a fixed part of the spelling (transparent) and words spelled with vowels (diacritics) omitted
(opaque). Three groups of Persian readers, namely developmental dyslexics (n=29, mean age=9.4, SD=1.4), unimpaired readers matched on age (n=49, mean age=9, SD=1.3), and reading age (n=23, mean age=7.2, SD=0.4) with the dyslexics performed on a short-term memory verbal test. The time taken to read aloud lists of words with opaque
and transparent spellings, the errors made on reading the words in each list, and the number of correctly recalled words in
each list was subjected to statistical analysis. The results showed that transparent words as a whole were read more accurately
than opaque words. However, recall of words was best for opaque words for the older group of unimpaired readers compared to
the transparent words, while the opposite was true for dyslexics and unimpaired reading age matched participants. The implications
of these results are discussed. 相似文献
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以菠萝蜜种仁淀粉为原料,采用β-淀粉酶（酶活为91500U／g）单酶法制备麦芽糖浆,在单因素实验的基础上,通过正交试验对工艺条件进行了优化,最佳工艺条件确定为：淀粉乳质量浓度20g／100mL、按质量分数加酶8％、pH5．5、（糖化）水解温度54℃、糖化时间8h。结果表明,在此条件下得到的产物淀粉转化率为41．6％,麦芽糖得率为47．5％。粗产品再经浓缩,得到的麦芽糖浆可溶性固形物含量（质量分数）为75％,色泽淡黄、体态均一透明、粘稠,具有麦芽糖香味,适合作为食品和食品辅料。 相似文献
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The objective of the present study was to examine the contribution of lexical and nonlexical processes to skilled reading
and spelling in Persian. Persian is a mixed orthography that allows one to study within one language characteristics typically
found in shallow orthographies as well as those found in deeper orthographies. 61 senior high-school students (mean age = 17;
8, SD = 4 months) attending schools in Iran were tested on reading and spelling of words and nonwords. The word stimuli differed
in terms of reading transparency (transparent when all phonemes have corresponding letters vs. opaque when short vowels were
not marked with a letter) and spelling polygraphy (nonpolygraphic phonemes vs. polygraphic phonemes). The nonwords were transparent
and nonpolygraphic. The reading results showed that both transparent and opaque words were read faster than nonwords, and
that transparent words were read faster than opaque words. Moreover, both transparent and opaque words were affected by word
frequency. These findings suggest that skilled readers of Persian relied on lexical processes to read words. In contrast,
the spelling results failed to show a word-advantage effect suggesting that skilled spellers of Persian rely on nonlexical
processes to spell words. Moreover, orthographic complexity also affected spelling. Specifically, nonpolygraphic words were
spelled faster than polygraphic words for both transparent and opaque words. Taken together, the findings showed that skilled
reading and spelling in Persian rely on different underlying processes. 相似文献