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The length and fineness of fibers are critical to the strength of yarns. Much research has been conducted on the issue in
the past decades. Zeidman and Sawhney introduced a new parameter called strength efficiency (SE) of fibers in a yarn using
an elaborate probabilistic method. Their final formula, a non-dimensional measure, describes the influence of the fiber length
distribution on the strength of yarn. The result, however, is based on the assumption that the fibers are identical in all
respects including their cross-sectional area. The influence of fiber fineness can not be seen in their formula. In fact the
joint influence of fiber length and fineness is rarely studied. We derive a new strength efficiency of the joint influence
of fiber length and fineness on the basis of Zeidman’s result. The conclusion is helpful to the understanding of the comprehensive
influence of fiber length and fineness on the strength of yarn. Furthermore, we give a plausible method to estimate the critical
length defined by Zeidman. The result can be applied to the research of the properties between fibers and yarns. 相似文献
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本文是对红麻茎发育进行解剖研究的结果。研究表明:红麻茎韧皮纤维层、木质部的发育均以旺长期最快;束纤维横切面积是后分化大于先分化的纤维束,而单纤维横切面积则是先分化大于后分化的纤维;红麻茎木质部发育的速度往往数倍于韧皮部;不同肥料对麻茎生长的影响,N肥以生长前期影响最大,而K肥对麻茎发育的影响以旺长期效果最为明显,作为选纸原料的红麻更应重施K肥。 相似文献
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Summary The amount of P- and K-application to the seed-potato crop did not show any influence on the chemical composition of the immature
harvested tubers, nor on the productivity if used as seed. Nitrogen had a marked influence on the chemical composition of
the tubers.
Seed from plots with high nitrogen dressing showed a tendency to give fewer main stems. Concerning the productivity of the
seed the experiments showed contradictory results. It is concluded that the amount of fertilizer applied to the seed-potato
crop is of little importance for the productivity of the progeny.
Retired in 1965. 相似文献
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剪切特性指标可以用来评价茶叶的嫩度,本文通过剪切试验获得了茶叶剪切特性的力学指标(硬度、破坏能、破坏力及破坏应力等),同时针对茶叶梗直径尺寸较小,运用图像分析的方法,获得茶叶梗外形尺寸及其他参数,综合分析建立了不同品种茶叶嫩度和剪切力学指标之间的数学模型,为客观评价茶叶的等级提供新的手段和研究方法。 相似文献
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利用统计软件SPSS,对肥效试验的数据进行随机区组设计分析、裂区区组设计分析,应用该软件能使较为繁琐的统计过程变为更简单、直接、准确。 相似文献
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选用感稻曲病品种辽粳401为研究对象,分析单穗上菌球数量以及菌球所在位置对水稻产量、加工品质、蒸煮食味品质的影响。结果表明,辽粳401单穗上菌球的数量以1~3个为主,随着单穗菌球数量增加,产量和品质逐渐降低,产量降低2.71%~35.47%,垩白粒率增加7.02%~94.90%,整精米率降低0.81%~13.18%。综合水稻产量和稻米品质数据发现,稻曲球对辽粳401的影响以单穗上产生3、6、9个菌球为分界点。产生在辽粳401穗位上部的菌球对稻米产量和品质影响大于产生在穗位中部和下部的菌球,穗位上部产生3个稻曲球可以造成辽粳401产量损失18.56%。 相似文献
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茶叶抗癌研究二十年 总被引：4，自引：1，他引：3
对茶叶抗癌研究的世界进展进行了分析和综述。从1987年日本富田熏最早报道茶叶提取物可以抑制人体癌细胞起,全世界约发表了4000~5000篇关于茶叶抗癌的研究论文。作者将这些研究分为四个阶段:八十年代后期到九十年代中期主要集中在活体外、活体内以及临床实验,九十年代中期到新世纪初主要在流行病学研究和抗癌机理的研究,新世纪初继续进行抗癌机理研究同时进行活性成分在动物和人体内的代谢、运转和归宿的研究,从2004年起开始了儿茶素类化合物的结构修饰和改造以期提高其生物可利用性和生物活性。本文重点对2003年以来的文献分流行病学实验、抗癌机理、儿茶素类化合物在动物和人体中代谢与归宿、儿茶素类化合物的结构修饰和改造与生物活性等几个方面进行了综述,并就茶叶抗癌的应用前景进行了讨论。 相似文献
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Here we propose an original study on the effect of an interruption and slowing of the fermentation of yeast-based leaven on the physical properties of bread. 相似文献
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基于浙江、江西、安徽、湖南四省342户农户水稻种植的微观数据,运用统计分析方法,研究影响长江中下游稻区农户用种行为的主要因素。结果显示,农户用种行为受水稻种植规模、农户年龄、从事水稻种植年份、信息获取难易程度和是否拥有农业保险等因素影响。提出相应对策建议：通过育种政策引导培育广适性品种,提升农业技术推广的深度和广度,通过补贴政策引导鼓励农户适度规模经营,培育家庭农场等新型农业经营主体,扩大农业保险以提升稻农抗风险能力。 相似文献
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C. J. SPARKE 《Grass and Forage Science》1985,40(4):403-409
After bracken control with asulam the surface litter was removed by raking, burning or incorporation, or left in situ as a control. The proportion of grasses in the sward and the grass net herbage production was not significantly different on the four litter treatments 1 or 2 years after spraying.
Lime, phosphate and seed of Trifolium repens, Lolium perenne and Festuca rubra were applied to a similar set of four litter treatments. T. repens failed to establish in quantity on any treatment. A long period of dry weather following sowing may have been the initial reason, with competition from the established, more vigorous grasses subsequently being of importance. The sown grasses established most successfully where competition from the existing indigenous species had been removed by burning or incorporation of the litter and surface vegetation. Although these two treatments differed little in the proportion of sown grasses in the sward in the second season, the net herbage production of Lolium and Festuca was significantly higher on the incorporated than the burnt treatment. Net herbage production of these two grasses in the second season was significantly higher on the incorporated and the burnt treatments than it was on the control. After 2 years, total grass net herbage production was significantly greater on these two treatments than on the unfertilized, unlimed and unseeded control. 相似文献
Lime, phosphate and seed of Trifolium repens, Lolium perenne and Festuca rubra were applied to a similar set of four litter treatments. T. repens failed to establish in quantity on any treatment. A long period of dry weather following sowing may have been the initial reason, with competition from the established, more vigorous grasses subsequently being of importance. The sown grasses established most successfully where competition from the existing indigenous species had been removed by burning or incorporation of the litter and surface vegetation. Although these two treatments differed little in the proportion of sown grasses in the sward in the second season, the net herbage production of Lolium and Festuca was significantly higher on the incorporated than the burnt treatment. Net herbage production of these two grasses in the second season was significantly higher on the incorporated and the burnt treatments than it was on the control. After 2 years, total grass net herbage production was significantly greater on these two treatments than on the unfertilized, unlimed and unseeded control. 相似文献
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The effect of artificial dehydration and processing of red clover on nutrient digestion and absorption has been studied with sheep. A total of three diets were fed, each at an intake of 900 g DM d-1 ; comprising frozen (to represent fresh control), wafered and pelleted red clover.
Dehydration caused small depressions in energy and N digestibility. Grinding and pelleting had no further effect, although both treatments reduced the amount of energy digestion occurring in the rumen, frozen 63, dried 60, pelleted 48 MJ per 100 MJ digestible energy. Digestion of energy in the caecum and colon was increased on both dried diets, and in the small intestine on the pelleted diet.
Almost 40% of the extra duodenal energy on the pelleted diet was due to increased cellulose flow, with only 79% of digestible cellulose being digested in the rumen compared with 96% on the other two diets. There was an associated decrease in ruminal volatile fatty acid production of approx. 20%. Approximately half of the extra energy was due to an elevated flow of protein on the pelleted diet, but this increase was not reflected in amino acid absorption due to a reduced efficiency with the dried diets (frozen 72%, dried diets 54%).
The results demonstrate that dehydration and processing of red clover can markedly influence nutrient digestion and supply and thus offer attractive means of improving the nutritive value. 相似文献
Dehydration caused small depressions in energy and N digestibility. Grinding and pelleting had no further effect, although both treatments reduced the amount of energy digestion occurring in the rumen, frozen 63, dried 60, pelleted 48 MJ per 100 MJ digestible energy. Digestion of energy in the caecum and colon was increased on both dried diets, and in the small intestine on the pelleted diet.
Almost 40% of the extra duodenal energy on the pelleted diet was due to increased cellulose flow, with only 79% of digestible cellulose being digested in the rumen compared with 96% on the other two diets. There was an associated decrease in ruminal volatile fatty acid production of approx. 20%. Approximately half of the extra energy was due to an elevated flow of protein on the pelleted diet, but this increase was not reflected in amino acid absorption due to a reduced efficiency with the dried diets (frozen 72%, dried diets 54%).
The results demonstrate that dehydration and processing of red clover can markedly influence nutrient digestion and supply and thus offer attractive means of improving the nutritive value. 相似文献
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Here, we describe a nano-scale surface structure on the rat-tailed maggot, the aquatic larva of the Drone fly Eristalis tenax (L.). Larvae of this syrphid hover fly live in stagnant, anaerobic water-courses that are rich in organic matter. The larvae burrow into fetid slurry and feed on microorganisms which they filter out from the organic material. This environment is rich in bacteria, fungi and algae with the capacity to form biofilms that might develop on the larval surface and harm them. Using transmission and scanning electron microscopy we have identified an array of slender (typically < 100 nm in diameter) nanopillars that cover the surface of the larvae. The high density and dimensions of these spine-like projections appear to make it difficult for bacteria to colonize the surface of the animal. This may interfere with the formation of biofilms and potentially act as a defence against bacterial infection. 相似文献