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丹东是东北边陲享有"杜鹃城"之誉的中朝之间最大的边境城市,位于鸭绿江畔,与朝鲜民主主义人民共和国隔江相望。这里自然风貌保存完好,人文景观丰富:北有层峦叠嶂的青山为屏,南有一望无际的良田沃野与黄海相伴,河流、水库组成的水网交织在高山、丘陵和平原之间;有明长城东部起点的虎山长城,有我国万里海疆北部端点的江海分界碑,有反映20世纪50年代朝鲜战争史实的抗美援朝纪念馆,有弹痕累累的鸭绿江大桥 相似文献
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土工合成纤维土补强机理试验研究及工程应用 总被引:5,自引:0,他引:5
对土工合成纤维土(TEXSOL)的补强机理进行了理论分析,研究了各种因素对纤维土补强特性的影响规律及已有纤维土强度计算经验公式的缺陷,并在大量试验的基础上确定了一系列经验系数如K,Q,R,P等,得出了各种影响因素与纤维土补强特性的关系。研究结果表明,纤维土粘聚力的增量与纤维的韧度、细度及纤维土的配合比等参数有关;提出了能反映多种影响因素的纤维土补强计算经验公式;最后将直壁高度法推广到纤维土挡墙的设计中,并应用所提公式对纤维土挡墙进行了内部稳定分析。 相似文献
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山西二叠系河流沉积特征 总被引:3,自引:0,他引:3
山西西部二叠系沉积环境以河流为主,除曲流河外,还有为数不多的辫状河与交织河。曲流河以发育曲流沙坝、洪泛平原和决口扇为其特征。辫状河发育河道沙坝沉积,洪泛平原沉积不太发育。交织河以河道稳定为特征,伴有沼泽沉积,是理想的成煤环境。 相似文献
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一株株彩叶交织成锦似火焰流金一片片林丛赤橙黄绿倒映池中似水墨彩画一池池湖水翠绿淡绿墨绿似灿烂珊瑚五花海,有"九寨沟一绝"和"九寨精华"之誉。海拔2472米,水深5米,面积9万平方米,位于珍珠滩瀑布之 相似文献
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我国的四大沙漠是指塔克拉玛干沙漠、古尔班通古特沙漠、巴丹吉林沙漠和腾格里沙漠。
“大漠孤烟直,长河落日圆”。我国是沙漠比较多的国家之一,沙漠广袤千里,呈一条弧形带绵亘于西北、华北和东北的土地上。沙漠总面积约130万平方公里,占全国土地面积的13%左右。 相似文献
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从工程观点研究了实现抗突发差错的BCH编码、译码及其交织技术的一种软件方法。这种方法把复杂的纠错算法用简单的程序设计予以实现,可使误码率由10 ̄(-3)降至10 ̄(-7)。这种方法适用于卫星数据广播通信等等各个方面。 相似文献
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Temperature Effect on the Life History of Three Types of Brachionus calyciflorus Females 总被引:3,自引:0,他引:3
The effect of temperature on the life history characteristics of amictic females ( AF), unfertilized mictic females (UMF) and fertilized mictic females (FMF) in Brachionus calyciflorus was studied with replicated individual cultures at 20℃ ,25℃ and 30℃ , and with algae Scenedesmus obliquus for their food. There were highly significant effects of both temperature and female type, independently and interactively, on the duration of juvenile and post-reproduction periods, and the number of eggs produced by the rotifer per life cvcle. Among all the temperature-female type combinations, all the juvenile periods of FMF, and the post-reproduction periods of UMF and FMF at 20℃, were the longest, and the number of eggs produced by an UMF at 30℃ was the highest. There were highly significant effects of both temperature and female type on the duration of the reproduction period, but no clear correlation was observed between temperature and female type. The reproduction period of AF was longer than that of UMF and FMF.Only temperature influenced significantly the mean life-span of the three types of females. The duration of juvenile,reproduction and post-reproduction periods as well as the life-span of the three types of females were all reduced very significantly with rise of temperature, but the rates of reduction varied with female type. Among the three types of females, the number of eggs produced per life cycle by an UMF was the highest, and that of a FMF was the lowest. A significant relationship between the number of eggs produced per life cycle and temperature was observed only in the UMF. 相似文献