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1.
刘国军  徐强 《森林工程》2004,20(4):40-41
通过研制稀有金属钨丝合股设备 ,并根据实际运行情况 ,对设备进行改造 ,完善了其加工性能 ,提高了产品的经济效益  相似文献   
2.
蚕茧价格变化规律及管理对策   总被引:10,自引:2,他引:8  
李瑞 《蚕业科学》1998,24(2):104-108
对1992年以来我国蚕茧价格和蚕茧供求变化进行分析,研究蚕茧价格的波动规律以及蚕茧均衡价格产生的条件,提出蚕茧价格管理的构想与建议。  相似文献   
3.
家蚕品种茧层生产效率的调查及相关分析   总被引:3,自引:0,他引:3  
251个家蚕品种的茧层生产效率平均为10.11%,最高12.19%,最低6.71%。二化性品种较高,一化性和多化性较低。中系二化种最高,平均10.54%,日二化种次之,平均10.39%,欧一化平均9.08%,日一化8.90%,多化平均8.72%。茧层生产效率与茧层量、茧层率、5龄一日茧层量成正相关,达显著或极显著水平;与5龄经过、全龄经过有正相关倾向,但不显著;与虫蛹率、死笼率、全茧量、消化率无一致倾向的相关。还调查了消化率和茧层转换率。  相似文献   
4.
The teleost pseudobranch, a reduced mandibular gill arch, morphologically closely resembles a gill hemibranch. It consists of several filaments bearing numerous lamellae. The vascular system of the pseudobranch also matches that of a gill, with afferent and efferent filamental arteries and the lamellar blood space. Despite the pseudobranch’s gill-like appearance, however, a gas exchange function is excluded in many teleosts by overlying opercular epithelium, effectively eliminating diffusional exchange with the external medium. The physiological function of the pseudobranch is still unknown, though its conspicuously close association with the ocular choroid rete mirabile, a structure supporting elevated oxygen partial pressures in the eye, suggests a role related to the process of oxygen secretion into the eyes of teleosts. In this paper we present new stereological data on the pseudobranch of rainbow trout (average weight: 478 ± 114 g, x ± SD, n = 12). The total Cavalieri volume of the pseudobranch was 46.4 μl (97 μl kg−1), consisting of lamellae 49%, connective tissue 43.8%, large blood vessels 4.5%, filamental cartilage 2.3%, and central venous sinus 1.3%. Lamellae were comprised of pillar and pseudobranchial cells 81%, blood space 12.3%, and lacunar tissue 6.4%. The inner surface of the blood space in the lamellae was 12.2 cm2 (25.5 cm2 kg−1), and its volume was 2.81 μl (5.88 μl kg−1). The results demonstrate the pseudobranch’s potential for physiological functions requiring a high surface area or surface-to-volume ratio, i.e. ion transfer, gas exchange and other regulatory processes. More detailed analysis of the function of the pseudobranch, however, has to remain subject of future morphological and physiological studies.  相似文献   
5.
通过6种类型的蚕茧干燥温度对蛹体适干率、茧丝品质等的影响的综合调查,认为二冲突温干燥的蛹体适干率、茧丝品质优于恒温干燥,而以头冲温度适中(110℃),二冲变温(100℃→90℃)时的蛹体适干率和茧丝品质略优于其他类型。  相似文献   
6.
Summary Although moisture requirements of Eisenia fetida are considered to be generally known, very few in-depth studies have been performed. The moisture preferences of juveniles as well as adults of this species were determined in moisture towers containing cow manure with a particle size bigger than 500 and smaller than 1000 m and an organic matter content of 54%. The clitellate worms showed a wider preference range than the juveniles but deposited most of their cocoons within the narrow range of 65%–70% moisture — a moisture range preferred by 80% of the juveniles. Growth studies of newly hatched worms at various moisture levels over a period of 90 days showed that growth rate and final biomass were influenced by moisture availability with a very low rate of growth at low as well as at high moisture levels. The change in biomass of clitellate specimens as well as their consecutively produced cocoons were monitored at different moisture levels. A clear relationship between mass of cocoons and biomass of the producing worms was established at presumably favourable moisture conditions. Furthermore, the relation between cocoon mass and the production rate of cocoons was also determined, which showed that cocoon mass increased concomitantly with increase in cocoon production. The study also showed that clitellum development was increased at moisture levels above 64%. The onset of cocoon production was, however, earliest at slightly lower moisture levels, from which it is concluded that the optimal moisture level for growth and development of clitella are not necessarily optimal for the production of cocoons.Dedicated to the late Prof. Dr. M.S. Ghilarov  相似文献   
7.
本研究表明,无论二元种还是四元种,五龄食桑96小时的青蚕,就可结小型茧。随食桑时间延长,其全茧量和茧层量迅速增加,茧层率呈直线上升。四元种个体间茧质开差大于二元种。食桑6足天(144小时)到7足天(168小时),二元种的茧层率增长减缓,而四元种仍不减慢。到食桑7足天后的四元种个体间茧质开差缩小到同二元种几乎相仿。因此,五龄后期良桑饱食是提高四元种茧质整齐度的重要途径。  相似文献   
8.
对 3个不同茧丝纤度蚕品种的茧丝表面及断面结构扫描电镜观察研究 ,发现不仅其纤度大小有极显著的差异 ,而且茧丝切口形态也有很大变化 ,并与生丝的物理性质测定结果相一致。  相似文献   
9.
通过采用聚集度指标检验的方法,对门源草原毛虫茧在矮嵩草草甸中的空间格局进行研究。结果表明,该虫雄茧(内有雄蛹)和雌茧(内有雌蛹或雌成虫或卵)的空间分布型属于聚集分布。并测定了茧个体群大小,分析了聚集原因,为野外抽样调查,密度估计及预测预报提供了依据。  相似文献   
10.
蓝藻在植物界中的分类地位是最为低等和原始的,其分布范围极为广泛。近年来,蓝藻在渔业生产、生物固氮、环境保护和监测以及植物分类系统的研究中,表现出愈来愈重要的作用。作者自1981~1989年的秋季,在呼和浩特市地区选择了十几个采集点进行采集,初步对呼和浩特市地区秋季淡水蓝藻进行了系统的调查与分类研究,这项工作在内蒙古尚为空白。根据这项研究,呼和浩特市地区秋季淡水蓝藻共有3个目,4个科,17个属,26个种,其中有7个种作为存疑种,尚需进一步研究。  相似文献   
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