Do Chinese and American contributions in top journals have an equal citation potential?

Purpose： We want to contribute to the evaluation of Chinese research, focusing on contributions in top journals. Design/methodology/approach： Using a Mann-Whitney test we investigate if contributions in Nature, Science or the Proceedings of the National Academy of Sciences of the United States of America （PNAS） by Chinese or American authors only, i.e. articles for which all authors have a Chinese or an American address, have a different citation potential. Findings： There is no reason to state that Chinese and American contributions in these top journals have a different citation potential. Research limitations： Because of the small numbers involved we were not able to make a distinction between publications in Nature, Science or the Proceedings of the National Academy of Sciences of the United States of America. Practical implications： These results suggest that the better Chinese research results are of a similar level as those by American colleagues. Originality/value： It is well-known that the number of citations per publication by Chinese authors is still lagging with respect to leading scientific nations and in particular compared with the USA. We have shown that this difference does not necessarily hold in contributions in Nature, Science or the Proceedings of the National Academy of Sciences of the United States of America.

PHASE RETRIEVAL OF TIME-LIMITED SIGNALS

The problem of reconstructing a signalφ（x） from its magnitude ｜φ（x）] isof considerable interest to engineers and physicists. This article concerns the problem of determining a time-limited signal f with period 2π when ｜f（eix）l is known for x∈[-π,π]. It is shown that the conditions ｜g（eix）｜ = ｜f（eix）｜ and ｜g（ci（x＋b）） -g（eix）｜ =f（ei（x＋b）） - f（eix）｜, b ≠ 27π, together imply that either g = wf or g = v f, where both w and v have period b. Furthermore, if b/2π is irrational then the functions w and v b is rational then w takes the form reduce to some constants c1 and c2, respectively; ifb/2π is rational then w takes the form w=elexB1（e1x）B2（elx）and v takes the form ei（x2πN/b＋a）B1（elx）B2（elx）,where B1 and B2 are Blaschke products.