用于铲刀连接座凹球面的淬火感应器及配用尺寸确定方法

针对淬火感应器及配用尺寸的确定方法，通过采用方铜管制作感应圈的有效感应弧端和导磁体的驱磁作用，解决了感应加热效率提升以及圆环效应的影响问题；采取感应器冷却用水与感应淬火冷却介质合二为一的方法，解决了铲刀连接座凹球面淬火时所需冷却介质的问题；通过分析给出了淬火感应器配用尺寸的确定方法。另外，所述感应器及配用尺寸的确定方法，构思新颖，结构合理，易于制作，且方法简单可行，具有很好的使用价值，并已申报了国家专利。     

Reproductive strategies in small populations: using Atlantic salmon as a case study

Abstract –  Wild salmonid populations with only a few breeding adults may not exhibit a significant reduction in genetic variability compared with larger populations. Such an observation suggests that effective population sizes are larger than population size estimates based on direct adult counts and/or the mating strategy maximises outbreeding, contributing to increased heterozygosity. In the case of wild Atlantic salmon Salmo salar populations, stratification by age classes and sexes on the spawning grounds avoids inbreeding and increases genetic variability. We studied the breeding composition of four Spanish salmon populations. Over a 7-year period we concluded that the probability of within-cohort mating is very low: females generally reproduce after two sea-winters whereas males reproduce mostly as one sea-winter ( grilse ) and/or mature parr. Considering different levels of contribution of mature parr to spawning derived from field surveys, we developed a simple model for estimating effective population sizes and found that they doubled with 65% parr contribution expected for rivers at this latitude (43°N), and ranged from 100–800 individuals. The effect of between-cohort mating was modelled considering different ranges of differences in allele frequencies between cohorts and resulted in 28–50% increases in heterozygosity when considering a 65% parr contribution. The complex mating strategy of Atlantic salmon contributes to explain the high levels of genetic variability found for small populations of this species. This model can probably be extended to other animal species with mating strategies involving different cohorts.     

千万不可忽视良种黄牛的保种问题

阐述了良种牛保种的重要意义．基因的随机漂移、选择与杂交、近交是特定基因从群体中消失的主要原因，群体及其有效含量和系统选育的科学组织是保种的重要内容。最后介绍我国良种牛的保种方法及其存在的问题，并提出解决的办法。     

家兔发情状态与受胎率和产仔数关系的研究

本文研究了家兔的发情状态与配种后的受胎率，以及产仔数之间的关系。以家兔阴粘膜颜色作为表观指标，将家兔的发情分为５个状态，其相应的阴粘膜颜色分别为：苍白、粉色、红色、大红、黑紫。经促排２号诱发排卵后，人工授精，相应状态下的受胎率为：２９．５％、４２．９％、５６．８％、５３．８％、２５．０％；相应状态下的平均产仔数分别为：５．５４、６．６９、６．６２、７．２１、５．５２。用促排３号处理后，相应状态下的受胎率为：９．０％、４３．２％、５３．２％、７０．０％、２１．７％。结果表明：无论是用促排２号，还是用促排３号处理，当阴粘膜颜色为苍白和黑紫时的受胎率或产仔数，都显著地低于或少于阴粘膜颜色为粉色、红色、大红时的受胎率（Ｐ＜０．０１）或产仔数（Ｐ＜０．０５）。说明，家兔的发情状态与配种后的受胎率和产仔数有密切的相关     

花生种子大小和重量对生长和产量的影响

花生种仁的大小及重量对出苗速度及出苗率、幼苗的生长和发育、植株的花芽分化和成花率以及荚果产量等有很大的影响。大粒优质种仁可提高出苗速度2～5d及出苗率3％～5％，植株生长健壮，花芽分化增多，成花率高，最终获得高产。     

辽东湾北部近海海域表层沉积物类型及分布特征

对2004年采自辽东湾北部近海海域的16个表层沉积物样品作了粒度分析和粒度参数计算,并进行了沉积物分类和分布特征的研究,结果表明,辽东湾北部近海的表层沉积物粒度主要由粉砂组成,平均含量65.15%,平均粒径5.031。总的特征是在5~10 m等深线,沉积物粒度的平均粒径由东部的4.530、中部的5.050逐渐增大到西部的6.236。沉积物粒度的组成类型由东向西按粉砂质砂→砂质粉砂→粉砂→砂-粉砂-黏土→黏土质粉砂由粗至细排列。     

饵料种类、温度和规格对硬壳蛤的同化率的影响

试验结果表明,温度和规格对硬壳蛤同化率的影响不显著(P>0.05);饵料种类对硬壳蛤同化率影响显著(P<0.05).其中小球藻和湛江等鞭金藻的同化率显著高于小新月菱形藻(P<0.05),而小新月菱形藻又显著高于扁藻(P<0.05).     

Burial rates of surrogate seeds in arable fields

The probability of seed consumption by surface-dwelling predators depends on the duration of seed exposure on the soil surface. We investigated seed burial using painted ceramic beads as surrogate seeds. Fifty beads of three size classes each were applied to small arenas within crop fields and their fates were followed from August to October. New sets of beads were applied as soon as most beads had disappeared from the soil surface. Bead availability on the soil surface declined immediately after placement, and then declined steadily over time, with increased loss during rain and management practices. Smaller beads were incorporated into the soil/litter matrix more easily than larger beads. Bead burial differed considerably among crop environments, with more burial in forage crops (red clover, lucerne) than in row crops (soyabean, maize). The fact that seed availability differed among crop environments suggests that it can be manipulated to maximise predation risk.     

Condition assessment of lamprey populations in the Yorkshire Ouse catchment,north‐east England,and the potential influence of physical migration barriers

• 1. River lamprey (Lampetra fluviatilis) and sea lamprey (Petromyzon marinus) are designated features of the River Derwent Special Area of Conservation (SAC) and the Humber Estuary (a possible SAC). This study determined the condition of lamprey populations in the Yorkshire Ouse catchment by assessing the species composition, distribution, abundance and size‐structure of larval (ammocoete) populations in five major tributary rivers (Derwent, Swale, Ure, Nidd and Wharfe).
• 2. According to EU condition assessment criteria, Lampetra populations (assumed to be mostly river lamprey) are at present in favourable condition, with site mean (±SE) densities ranging from 2.7 (±1.2) to 160.3 (±50.5) individuals m^?2 (all river means >2 individuals m^?2), and at least two size (≈age) classes present in optimal microhabitats. By contrast, no sea lamprey larvae were recorded, suggesting that populations of this species are in unfavourable condition.
• 3. Actions to protect and enhance nationally or internationally important stocks must be implemented from at least a catchment perspective, because many of the issues affecting such species are not localized. With respect to lampreys, particular attention should be given to protecting spawning and nursery habitats, improving water quality, reducing impingement at abstraction points, preventing exploitation at spawning grounds and increasing passage at potential physical obstructions.

Copyright © 2007 John Wiley & Sons, Ltd.     

推车式离心雾化喷雾机性能试验研究

对推车式离心雾化喷雾机进行性能试验研究，研究旋转式离心雾化特征、雾滴直径、雾滴沉降分布规律、雾滴沉积密度均匀性、风送低量喷雾效果等，掌握各参数相互匹配关系与工作机理，为进一步优化改进、产业化设计、关键部件精确工艺研究等提供技术支撑。