Hard Disk Drive硬盘驱动器 High Density Data高密度数据 Heating Degree Days (weather derivatives / insurance index converting temperature into prices)加热度天(天气衍生品/保险指标转换温度成价格) Holographic Disk Drive全息磁盘驱动器 Health Data Dictionary健康数据字典 Human Disorientation Device人类的定位装置 Horizontal Directional Drilling水平定向钻 Hardware Design Document硬件的设计文档 Head Down Display俯视显示器 Head-Down Display下视显示器 Hard Decision Decoding硬判决译码 Hierarchical Data Dictionary分级数据字典 Hyderabad (Pakistan)海德拉巴(巴基斯坦) Heavy-Duty Diesel重型柴油 Hammer Debounce Device (airguns)锤子Debounce装置(airguns)