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71.
72.
Based on theory of cylinders subjected to uniform internal pressure, the mechanical performance of a steel tubular column filled with equidistant fiber reinforced polymer (FRP) ring stiffening concrete is investigated. The solutions for the stress and displacement are regarded as the superposition of elementary and improved solutions. The elementary solutions are found by using two dimensional elastic theory. The improved solutions are found by using the Love displacement function method. Considering the conditions of the displacement continuum of the FRP ring and the steel tube exterior, a more accurate solution for an equidistantly FRP ring stiffened cylinder subjected to a uniform internal pressure is obtained. Several numerical calculations are also carried out. The results indicate the solutions possess good convergence.  相似文献   
73.
This study uses the linear stability analysis to understand the transition characteristics of thermocapillary convection in an annular pool with low Prandtl number (Pr=0.011) fluid. The annular pool is heated from the outer cylindrical wall and cooled at the inner wall. The bottom and top surfaces are adiabatic. The results show that with the increase of the aspect ratio, the critical Marangoni number and the critical wave number decrease. When the aspect ratio exceeds 0.12, the critical wave number keeps almost constant. With the increase of the radius ratio, the critical Marangoni number decreases slightly, while the critical wave number increases.  相似文献   
74.
东北主栽花生品种农艺性状及品质性状分析   总被引:2,自引:0,他引:2  
为了进一步提高东北地区花生新品种创新力度,加快新品种遗传改良进程,本研究针对东北主栽的33个花生品种从农艺、品质以及产量指标进行分析。结果表明,适合本地区推广的花生株高不超过40 cm,分枝数为5~9个,百仁重为(78.47±14.44) g,出米率为(72.84±3.65)%;相关分析中,结果枝数、单株饱果数随脂肪含量增加呈正相关,分枝数的增加与粗蛋白呈负相关;偏相关分析中,出米率对品质影响较大,呈偏正相关;灰色关联分析中,油酸与产量关联系数较大,粗蛋白与产量结果关联系数较小;从农艺性状与品质性状的聚类分析图中可以得出,东北地区主栽的花生品种遗传多样性比较丰富,为下一步主栽品种的单个性状的亲本改良提供了依据。  相似文献   
75.
近年发射的1 m/3 m高分辨率合成孔径雷达(Synthetic Aperture Radar,SAR)卫星为多云多雾地区土地利用动态遥感监测提供了重要数据源。为进一步检测高分辨率SAR卫星的适用性,采用对比分析和统计评价法,对TERRASAR、COSMO SkyMed、RADARSAT-2高分辨率SAR卫星中1 m聚束模式和3 m条带模式数据新增建设用地监测能力进行综合评价。结果表明,1 m聚束模式新增建设用地属性识别准确率可达到80%,3 m条带模式识别准确率约75%,基本新增建设用地监测应用需要。  相似文献   
76.
The agent - construction system, as a new public project management mode, has been practiced in some cities and attracted attention from the society. This paper firstly studies the features and operation modes of agent - construction system, and discusses the agent - construction system from the viewpoints of promoting competition, nourishing agent -construction enterprises, setting up a supervisory and encouraging mechanism, and its connection with the governmental project procurement system etc.  相似文献   
77.
利用一氧化氮供体硝普纳(sodium nitroprusside,SNP),研究了一氧化氮对铜、镉胁迫下平邑甜茶幼苗的活性氧代谢的影响。结果表明:在200μM的CuCl2或CdCl2处理下,25~200uM的SNP能够提高平邑甜茶幼苗根系和叶片的SOD,POD活性,降低根系和叶片的超氧阴离子(O-2)产生速率及丙二醛(MDA)含量,表明适当浓度的一氧化氮可以通过提高部分抗氧化酶活性来缓解铜、镉胁迫对平邑甜茶幼苗的伤害。  相似文献   
78.
以南方重要造林树种邓恩桉、本沁桉、巨桉、直杆蓝桉为研究对象,采用溶液培养方法,在20d试验期中分别研究了不同质量分数的铜、锌、镉对这4种桉树种子发芽与根伸长的污染效应。结果表明,不同质量分数的铜、锌、镉对邓恩桉、本沁桉、巨桉与直杆蓝桉的种子发芽与根伸长均存在抑制效应,其中对种子的发芽具有明显的抑制性,但对种子发芽过程(发芽高峰期)影响较小。4种桉树在试验所设计的3种重金属Cu、Zn、Cd中均表现出对Cu具有较高敏感性。另外,重金属质量分数与种子发芽抑制率之间普遍存在着显著的回归关系,且对根伸长的抑制效应明显大于对种子发芽的影响,高质量分数重金属对根伸长的抑制率均达80%以上,甚至达到100%。  相似文献   
79.
[Objective] The purpose of this study was to map QTLs for yield, maturity, and fiber quality traits of cotton interspecific hybrid populations and to mine favorable alleles from the cotton genome for QTL fine mapping, gene cloning, and molecular marker-assisted selection. [Method] Four BC1F1 populations, E(E3), E(3E), (E3)E, and (3E)E, were developed by crossing sea island cotton 3-79 ("3") and upland cotton 'Emian 22' ("E"), and with "Emian 22" as the recurrent parent. BC1F2 populations derived from BC1F1 populations were phenotyped to allow mapping of QTLs for yield-, maturity-, and fiber quality-related traits on chromosomes showing segregation distortion. [Result] A normal distribution test indicated that six fiber quality-related traits, except for the micronaire value in E (E3) and the short fiber ratio in all populations, followed a normal distribution pattern; in contrast, earliness-related traits were not normally distributed in all populations, which suggests that genotype-environment interactions have strong effects on maturity-related traits. Using composite interval mapping, 47 QTLs were detected on three chromosomes (2, 16, and 18): 15 in (E3)E, 13 in (3E)E, 12 in E(E3), and 7 in E(3E), with the phenotypic variation explained (PVE) ranging from 8.8%–30.9%. A total of 27 fiber-related QTLs were discovered, with the PVE ranging from 9.0%–30.9%. Five yield-related QTLs (PVE = 8.8%–17.4%) and 13 maturity-related QTLs (PVE = 9.4%–19.4%) were also identified. [Conclusion] Comparison analysis showed that most QTLs in our study were consistent with the MetaQTL, including QTLs for boll weight, fiber length, fiber length uniformity, lint percentage, and micronaire value on chromosome 2; QTLs for fiber length, fiber strength, and fiber length uniformity on chromosome 16; and QTLs for boll weight, date of boll opening, fiber length, fiber strength, fiber length uniformity, and micronaire value on chromosome 18. Several detected QTLs in our study were not found in the MetaQTL, such as QTLs for date of boll opening and lint percentage on chromosome 16 and a QTL for the date from seedling to flowering stages on chromosome 18. These newly identified QTLs may provide novel insights for cotton QTL analysis.  相似文献   
80.
论述微生物法发酵玉米秸秆生产单细胞蛋白的研究进展。主要介绍单细胞蛋白的开发利用价值,用微生物法发酵玉米秸秆纤维素生产单细胞蛋白的微生物菌种、简单工艺方法等,以及单细胞蛋白在食品工业及饲料工业上的应用和发展前景。  相似文献   
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