双焦点的英文

• bifocus
  ◇双焦点镜片 ultex; 双焦点透镜 bifocal

• 双    two; twin; both; dual
• 焦点    focal point; focus
• 双焦点x线管    twin focus x-ray tube
• 双焦点的    bifocal
• 双焦点管    bifocal tube; double-focus tube; dual-focus tube; dual-focustube
• 双焦点镜    double locus lens
• 双焦点镜片    ultex
• 双焦点球管    double focus tube
• 双焦点透镜    bifocal lens; lens, bifocal
• 双焦点眼镜    bifocal eyeglasses; bifocal glasses; bifocal slasses; bifocal spectacles; divided ectacles; divided spectacles; dividend spectacles; pantoscopic ectacles; pantoscopic spectacles
• 双焦点干涉仪    double-focus interferometer
• 双焦点检眼镜    bifocal ophthalmoscope
• 整块双焦点镜    ultex
• 单块双焦点透镜    one-piece bifocal lens
• 单中心双焦点透镜    monocentric bifocal lens
• 低凹双焦点透镜    depressed bifocal lens
• 复式双焦点透镜    double bifocal lens
• 垒球样双焦点透镜    baseball bifocal lens
• 磨制双焦点透镜    executive bifocal lens
• 劈开双焦点透镜    split bifocal lens
• 全视双焦点透镜    complete vision bifocal lens
• 融合双焦点透镜    blended bifocal lens
• 熔合双焦点透镜    fused bifocal
• 双焦点干涉显微镜    double focus interference microscope
• 双焦点透镜试镜架    test frame for bifocus lenses

• Dual - focus tube
  双焦点管
• Third , this dissertation analyzes the complicacy of result size estimation problem for xml structure based query optimization compared to its counterpart in traditionally relational database , and proposes a full - featured result size estimation algorithm for xml query , sxm . for simple path expression query , this dissertation proposes a dynamic synopsis model for xml data based on the concept of f - stable and b - stable , xmap . for complicated path expression query , this dissertation adopts an improved bifocal sampling method for result size estimation
  第三，分析了xml结构化查询优化中的查询代价估计问题与传统关系型数据库中的查询代价估计问题的区别，提出了一套完整的xml结构化查询代价估计体系sxm ，包括对简单路径表达进行查询代价估计的动态xml数据统计模型xmap ，对复杂路径表达进行查询代价估计的双焦点例举法，以及对值匹配条件进行查询代价估计的基于小波的多维直方图方法，并能将多种查询表达的查询代价估计结果结合在一起，以给出一个完整的xpath查询的代价估计。