油气润滑用微型油泵的性能

为高速滚动轴承油气润滑系统研制出膜片式微量油泵，试验测出该油泵流量与电压，频率的关系曲线，进行了供油均匀性试验，结果表明，该泵能满足油气润滑要求。     

Structure of a bacterial 30S ribosomal subunit at 5.5 A resolution.

The 30S ribosomal subunit binds messenger RNA and the anticodon stem-loop of transfer RNA during protein synthesis. A crystallographic analysis of the structure of the subunit from the bacterium Thermus thermophilus is presented. At a resolution of 5.5 A, the phosphate backbone of the ribosomal RNA is visible, as are the alpha-helices of the ribosomal proteins, enabling double-helical regions of RNA to be identified throughout the subunit, all seven of the small-subunit proteins of known crystal structure to be positioned in the electron density map, and the fold of the entire central domain of the small-subunit ribosomal RNA to be determined.