983 resultados para 367.224


Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Bericht über die TECHNISCHE KONFERENZ DER FAO und den XII. INTERNATIONALEN KÄLTEKONGRESS vom 30.8. - 8.9. 1967 in Madrid

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A simple and practical model is used to analyse the influence of substrate surface defect on the optical characteristics of a single-layer coating. A single-layer coating is prepared and its optical properties are fitted. Some explanations for the origin of the transition layer are presented. It is concluded that there is a transition layer forming between the substrate and coating, which is attributed to substrate surface defects, and its refractive index change is nearly of linearity.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

用低能氧等离子体对电子束热蒸发后的沉积氧化锆薄膜进行了后处理。通过对其光学性质、缺陷密度、弱吸收及抗激光辐照等性质的研究后发现,经氧等离子体处理后的氧化锆薄膜的折射率、消光系数、缺陷密度及吸收率等均有所降低,薄膜的激光损伤阈值较未处理的样品有了较大的提高。分析探讨了氧等离子体处理技术对薄膜性质的影响。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

用辉光放电质谱法和二次离子质谱仪测定了两种HfO2材料及它们相应的单层膜中的杂质含量,结果发现,无论是在体材料中还是在用电子束蒸发技术沉积的材料单层薄膜中,ZrO2都是这两种HfO2材料中最主要的杂质。而且,这两种HfO2材料中Zr含量的差别远远大于Ti、Fe含量的差别,这说明Zr含量的差别正是引起两种HfO2膜层光学性能差别的原因。用这两种不同纯度的HfO2材料与同一纯度的SiO2材料组合,沉积形成266nm的紫外反射镜,实验结果表明这两种反射镜的反射率分别在99.85% 和 99.15%左右。这个结果与依据单层膜得出的光学常数所设计的结果符合的很好。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本书为读者提供了蕨类植物学的理论基础和分类方法,完善和修订了秦仁昌系统(蕨类植物门),反映了我国蕨类植物系统分类学研究的当代水平。全书以秦仁昌系统为理论基础,全面论述国产的蕨类植物63科224属,并对蕨类植物的分类原则和方法、研究历史、主要学说或观点及存在的重大问题也加以介绍和评述,提出作者的见解。书中对秦仁昌系统在七个方面所作的修改,均为国际上蕨类植物系统发育研究的重大课题,而书中对秦仁昌系统所作的完善及补充,在一定程度上起到总结过去70年来国内蕨类研究工作的作用,对今后研究工作和教学工作的开展将起到积极的作用。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We verified the age and growth of swordfish (Xiphias gla-dius) by comparing ages determined from annuli in fin ray sections with daily growth increments in otoliths. Growth of swordfish of exploitable sizes is described on the basis of annuli present in cross sections of the second ray of the first anal fins of 1292 specimens (60−260 cm eye-to-fork length, EFL) caught in the region of the Hawaii-based pelagic longline fishery. The position of the initial fin ray annulus of swordfish was verified for the first time with the use of scanning electron micrographs of presumed daily growth increments present in the otoliths of juveniles. Fish growth through age 7 was validated by marginal increment analysis. Faster growth of females was confirmed, and the standard von Bertalanffy growth model was identified as the most parsimonious for describing growth in length for fish greater than 60 cm EFL. The observed growth of three fish, a year-old in size when first caught and then recaptured from 364 to1490 days later, is consistent with modeled growth for fish of this size range. Our novel approach to verifying age and growth should increase confidence in conducting an age-structured stock assessment for swordfish in the North Pacific Ocean.