Converter stations transform alternating current to direct current for transmission and back to ac again for distribution to consumers 换流站将交流电转换成直流电传输，然后又转换回交流电用于分配到用户。
Introgression ( introgressive hybridization ) the introduction of genetic material from one gene pool to another by hybridization and subsequent back - crossing to one or other of the parents 渐渗现象（渐渗杂交） ：是通过杂交或其后代与某个亲本回交，遗传物质从一个基因库被引入另一个基因库的现象。
One of britain s wealthiest and most secretive businessmen yesterday launched a surprise 133 . 1m takeover bid for newcastle united after announcing he had already bought a 41 . 6 per cent stake in the club for 55 . 3m 洋基红袜同在美联东区，对战胜负一来一往，每回交手将拉出一场差距不属该区的球队，成败之别仅有
Amplified fragment length polymorphisms ( aflps ) , random amplified polymorphic dna ( rapd ) and microsatellite markers were used for genome mapping in the pacific oyster , crassostrea gigas thunberg 本研究利用aflp 、 rapd和微卫星标记，以一个回交家系[ ( miyagixhiroshima ) xmiyagi ]为作图群体，构建了长牡蛎的遗传连锁图谱。
Where the ranges of two species overlap , and fertile hybrids can be produced , these hybrids will tend to backcross with the most abundant species , so the offspring down many generations come to resemble the most abundant parents 两个物种的重合个体或是那些可育杂种将趋向于与优势种进行回交，因此，经过很多代之后，所得个体会与优势种的亲代相似。
The development of these new varieties ( strains ) indicated that using the summer type variety from low latitude area as the high - protein parent , and local high - yield accessions as the recurrent parental lines in modified backcross is an efficient strategy for high - protein , high - yield soybean breeding 育种实践证明，选择低纬度地区的夏大豆品种（系）作高蛋白基因源，创造高蛋白中间材料，采用本地丰产材料进行修饰回交，是高蛋白、高产大豆育种的一种有效方法。
Abstract : the main characters and seed set of bc1 ， bc2 ， bc1f2 from ms line back - crossing with the pollen of hybrid rice were studied . the appearance of a large number of self fertile plants in ms line was analyzed . the effect of introgression of restoring genes on ms line purity and hybrid yield in indica and japonica rice was discussed . it was pointed out that “ iso - cytoplasm restorer line ” was seriously reducing the purity of ms line and that hybrid rice was unsuitable for isolation zone in the seed production fields 文摘:研究了杂交稻花粉对母本不育系回交后代群体bc1 、 bc2 、 bc1f2的主要农艺性状和育性表现，分析了不育系中出现大量自交结实株的原因，讨论了恢复基因渗入对籼、粳不育系纯度和杂交稻产量的影响，指出“同质恢”对降低不育系纯度的严重性和杂交稻作制种田隔离区的不合理性。
The results showed , compared with experimental common wheat , annong waxy 1 should be improved in plant - height , ear - length , 1000 - kernel weight by hybridism and back - cross , while the difference among protein content , ash content , wet gluten contents were not significant , but the waxy wheat grain hardness value was lower 结果表明，与供试的普通小麦品种（系）相比较， “安农糯1 ”在株高、穗长和千粒重等农艺性状上均不理想，需要通过杂交和回交等方式进一步改良；蛋白质含量、灰分、湿面筋含量等变化不大。
