2,976 research outputs found
catena-Poly[[aquaÂ(dipyrido[3,2-a:2â˛,3â˛-c]phenazine-Îş2 N 4,N 5)iron(II)]-Îź-pyrazine-2,3-dicarboxylÂato-Îş3 N 1,O 2:O 3]
In the title compound, [Fe(C6H2N2O4)(C18H10N4)(H2O)]n, the FeII ion adopts a slightly distorted octahedral mer-FeN3O3 geometry, arising from one N,Nâ˛-bidentate dipyrido[3,2-a:2â˛,3â˛-c]phenazine ligand, one N,O-chelating pyrazine-2,3-dicarboxylÂate dianion and one water molÂecule. An O-bonded symmetry-related dianion completes the coordination of the metal. The bridging dianion results in a one-dimensional polymeric chain. Aromatic ĎâĎ stacking interÂactions between ligands [centroidâcentroid separations = 3.528â
(2) and 3.741â
(2)â
Ă
] and OâHâŻO and OâHâŻN hydrogen bonds link the chains together, leading to a three-dimensional supraÂmolecular network
catena-Poly[[aquaÂ(pyrazino[2,3-f][1,10]phenanthroline-Îş2 N 8,N 9)cobalt(II)]-Îź-pyrazine-2,3-dicarboxylÂato-Îş3 N 1 O 2:O 3]
In the title compound, [Co(C6H2N2O4)(C14H8N4)(H2O)]n, the Co atom is bonded to one N,Nâ˛-bidentate pyrazino[2,3-f][1,10]phenanthroline (Pyphen) ligand, one N,O-bidentate pyrazine-2,3-dicarboxylÂate (PZDC) dianion and one water molÂecule in a distorted octaÂhedral mer-CoN3O3 geometry. The CoII atoms are bridged by the PZDC dianions, forming an infinite one-dimensional chain running along the b axis. Adjacent chains pack together through ĎâĎ stacking interÂactions [centroidâcentroid separations = 3.498â
(4) and 3.528â
(4)â
Ă
], and OâHâŻO and OâHâŻN hydrogen bonds involving the water molÂecule complete the structure
The Role of Digital-Media-Based Pedagogical Aids in Elementary Entomology: An Innovative and Sustainable Approach
It has been challenging for city school pupils to learn about insects, given the lack of live insects. To overcome this challenge, the objective of this study is to propose the use of emerging digital media, namely three-dimensional printing (3DP) technologies, to create reusable, fake, âliveâ insects. In this study, we designed two 3D-printed pedagogical aids to support elementary entomology. The first aid was a set of cards showing photos of the 3D-printed insect prototype, which could help the learners in close observation of the insect bodyâs regions and parts, and the second 3D-printed aid was a construction kit mimicking physical insects, which were made of an enlarged 3D-printed insect prototype. The two aids were used in our field experiment to examine the effectiveness in learning and motivation. A total of 153 pupils were grouped into three groups (one using the existing multimedia e-book, one using the first 3DP aid, and one using the second aid). The results confirm that the digital media applicationâin this case, 3DP technologiesâwere able to compensate for the lack of the live insects. These results raised our confidence in using a customized size 3D-printed insect prototype to enhance rudimentary entomology inside the classroom. If the 3DP technologies are used properly, they could offer an innovative and sustainable solution
Topological sound
Recently, we witnessed a tremendous effort to conquer the realm of acoustics as a possible playground to test with topologically protected sound wave propagation. In this article, we review the latest efforts to explore with sound waves topological states of quantum matter in two- and three-dimensional systems where we discuss how spin and valley degrees of freedom appear as highly novel ingredients to tailor the flow of sound in the form of one-way edge modes and defect-immune protected acoustic waves. Both from a theoretical stand point and based on contemporary experimental verifications, we summarize the latest advancements of the flourishing research frontier on topological sound.X.J.Z. and L.M.H. are supported by the National Natural Science Foundation of China (Grant No. 11625418 and No. 51732006). M.X. is supported by the U. S. National Science Foundation (Grant No. CBET-1641069). Y.C. acknowledges the support from the National Natural Science Foundation of China (NSFC) (Grant Nos. 11834008,11874215, 11674172, and 11574148) and from the National Basic Research Program of China (Grant No. 2017YFA0303702). J.C. acknowledges the support from the European Research Council (ERC) through the Starting Grant No. 714577 PHONOMETA and from the MINECO through a RamĂłn y Cajal grant (Grant No. RYC-2015-17156
Optimization of adefovir therapy in chronic hepatitis B according to baseline predictors and on-treatment HBV DNA: a 5-Year prospective study
General iterative algorithms for mixed equilibrium problems, variational inequalities and fixed point problems
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