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We cannot offer a definitive answer, and it is likely that issues of timing and the sociology of scientific culture are important. Nevertheless, looking at common factors among back sex 6 materials listed in SI Appendix, Table S7 is interesting. All of these materials can be synthesized using chemicals that are readily available back sex, and all but one (MOF-177) involve only chemicals that are cheap.

This suggests that at least in the MOF research community, materials in which chemical synthesis of component chemicals is required before materials synthesis from these components are unlikely to be supermaterials. It is encouraging to charcoal activated that the materials in SI Appendix, Http://movies-play.xyz/porn-tiny-girl/tylenol-arthritis-pain.php S7 came from work at a geographically and internationally diverse group of institutions.

All of the results above have examined whether replicate syntheses of MOFs exist but not what can be deduced about reproducibility from these replicates.

Back sex the materials shown in Fig. Among the materials listed in SI Appendix, Table S7, however, there are many replicate measurements of Back sex surface areas, a quantity that can be readily compared between experiments.

Back sex BET surface area is strongly correlated with pore volume, another commonly reported познавательно. augmentin ru извиняюсь (SI Appendix, Fig. Among the 528 replicate syntheses listed back sex SI Appendix, Table S7, 355 reported BET surface areas. Histograms of back sex reported BET surface areas back sex (A) UiO-66, (B) ZIF-8, (C) HKUST-1, (D) MIL-101(Cr), (E) IRMOF-1, and (F) MOF-177.

The number of reported surface areas (N) for each material is indicated in each figure. Blue text and vertical lines show the calculated theoretical values from defect-free and solvent-free crystal structures. These materials are back sex to be sensitive to moisture (30), so it is likely that this variation is related to differences in materials handling and history among the replicate experiments. UiO-66, ZIF-8, and MIL-101(Cr) are known to be relatively stable toward moisture (30) and they show less variation in surface area among replicates.

It is notable back sex for each material there are examples for which the surface area is much smaller than the theoretical value and examples back sex which the surface area is larger. In addition to materials degradation, incomplete removal of solvent from materials can lead to reduced surface areas (31, 32). It is therefore not surprising that each material in Fig.

These data suggest, however, that there back sex systematic variations in the back sex properties among many replicate back sex of these materials, implying that efforts to understand the phenomena that lead to these variations and more precisely describe the materials that are made would be useful.

Careful comparison of the precise synthesis conditions and experimental details among many replicates would be helpful to begin to address these issues, but this is beyond the scope of our current work. Because activation of MOFs can be a nontrivial issue (37, 38), it is conceivable that measured surface areas might improve over time as techniques for activating specific materials are improved. To see if there is evidence back sex this effect, we show back sex Fig.

The same data using the actual date of each report of synthesis is shown in SI Appendix, Fig. These data offer no support for the idea that the measured surface areas systematically improve back sex подробнее на этой странице during many replicate measurements.

A caveat in considering these data are that unlike efforts back sex make high-precision measurements of physical constants (38), the measurement of surface area in the majority of these reports is not the central aim of the work, instead it is a characterization technique used in support of some other scientific goal. Variation in BET surface areas of resynthesized MOFs from the year of their original synthesis.

The synthesis of 1 of these materials has been reported more than 3 times, but for every other material less information than this is available in published reports. We showed that the frequency of replications for these 130 materials can be described with a simple power-law back sex. This power-law model, however, does not appear to describe the most frequently replicated MOFs in the literature.

We identified 6 MOFs that could be described back sex supermaterials in the sense that they have been made far more frequently than a power-law model would predict. The synthesis of these materials has been replicated hundreds of times, an observation that creates opportunities to consider factors underlying experimental reproducibility читать статью variability that cannot be assessed for materials that back sex only been synthesized a few times.

Although replicate syntheses have been reported for only a small back sex of the 130 materials we studied, we found many instances where later work produced modified versions of these materials. These modified materials have a different chemical composition or crystal structure from the original material. Back sex may be that in many of http://movies-play.xyz/teen-orgasm/discovery-journal.php studies, a replicate synthesis of the original material was performed but the authors chose not to report the results.

If this is correct, this practice means that many opportunities for the scientific community to learn about the repeatability of materials synthesis are being missed.

Our study focused on MOFs, because the existence of curated libraries of these materials made it possible to select materials to analyze in an unbiased way. We do not know of any similar analysis for other classes of materials, so any discussion of how directly our findings will extend to other materials is speculative. Our methods, however, could readily back sex applied to other areas within materials chemistry. We hope that the work described here motivates future efforts of this kind.

All data relevant to the article is available back sex the SI Appendix. This work was supported by Center for Understanding and Control of Acid Gas-induced Evolution of Materials for Energy (UNCAGE-ME), an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Basic Energy Sciences under Award DE-SC0012577. This open access article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.

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Comments:

17.03.2020 in 07:51 Вацлав:
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19.03.2020 in 06:38 korchuzzku:
Какой забавный вопрос

19.03.2020 in 17:33 Беатриса:
Извиняюсь, но это мне не подходит.

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21.03.2020 in 21:22 Лидия:
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