1.PPF is staying tight-lipped, offering only a written statement.
PPF集团现在守口如瓶，仅在书面上做出声明。
2.It was resulted that the method was practicable and significant in modifying the Chinese standard of PPF testing.
测定试验结果表明，该方法是可行和实用的。因而，对修订透性测定的国家标准具有指导意义。
3.Discussion on the Mechanism of the Modification PPF Influencing the Compressive Strength of the Concrete
改性聚丙烯纤维影响混凝土抗压强度的机理初探