abstract background: we aimed to evaluate an approach to induced abortions during early pregnancies that controls the suction pressure and restricts the duration of the procedure. methods: three hundred patients programmed for induced early pregnancy abortions, hospitalized in the shandong provincial maternity & child care hospital from october 2013 to october 2015, were enrolled. patients were...

the austenitic stainless steel (ss) has been used as a material for  building  ultra  high  vacuum  (uhv)  chamber.  recently significant  efforts  have  been  concerned  a  comparing  the standard  cleaned  for  ultra  high  vacuum,  passivity  stainless. in  this work austenitic  nanocomposites were  synthesize by sol-  gel method. the morphologies  and  topographies  of  the samples  have  b...

We argue that the phenomenon of vacuum birefringence in strong inhomogeneous electromagnetic fields can be most efficiently analyzed in terms of a vacuum emission process. In this contribution, we exemplarily stick to the case of vacuum birefringence in a stationary perpendicularly directed, purely magnetic background field extending over a finite spatial extent. Similar field configurations ar...

Even if the electromagnetic field does not create pairs, virtual pairs lead to the appearance of a phase in vacuum-vacuum amplitude. This makes it necessary to distinguish the inand out-solutions even when it is commonly assumed that there is only one complete set of solutions as, for example, in the case of a constant magnetic field. Then inand out-solutions differ only by a phase factor which...