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991.
In this study, the titanyl and vanadyl phthalocyanine (Pc) salts (Bu4N+)2[MIVO(Pc4?)]2? (M=Ti, V) and (Bu3MeP+)2[MIVO(Pc4?)]2? (M=Ti, V) with [MIVO(Pc4?)]2? dianions were synthesized and characterized. Reduction of MIVO(Pc2?) carried out with an excess of sodium fluorenone ketyl in the presence of Bu4N+ or Bu3MeP+ is exclusive to the phthalocyanine centers, forming Pc4? species. During reduction, the metal +4 charge did not change, implying that Pc is an non‐innocent ligand. The Pc negative charge increase caused the C?N(pyr) bonds to elongate and the C?N(imine) bonds to alternate, thus increasing the distortion of Pc. Jahn–Teller effects are significant in the [eg(π*)]2 dianion ground state and can additionally distort the Pc macrocycles. Blueshifts of the Soret and Q‐bands were observed in the UV/Vis/NIR when MIVO(Pc2?) was reduced to [MIVO(Pc . 3?)] . ? and [MIVO(Pc4?)]2?. From magnetic measurements, [TiIVO(Pc4?)]2? was found to be diamagnetic and (Bu4N+)2[VIVO(Pc4?)]2? and (Bu3MeP+)2[VIVO(Pc4?)]2? were found to have magnetic moments of 1.72–1.78 μB corresponding to an S=1/2 spin state owing to VIV electron spin. As a result, two latter salts show EPR signals with VIV hyperfine coupling.  相似文献   
992.
The palladium–hydrogen system is one of the most famous hydrogen‐storage systems. Although there has been much research on β‐phase PdH(D)x, we comprehensively investigated the nature of the interaction between Pd and H(D) in α‐phase PdH(D)x (x<0.03 at 303 K), and revealed the existence of Pd?H(D) chemical bond for the first time, by various in situ experimental techniques and first‐principles theoretical calculations. The lattice expansion, magnetic susceptibility, and electrical resistivity all provide evidence. In situ solid‐state 1H and 2H NMR spectroscopy and first‐principles theoretical calculations revealed that a Pd?H(D) chemical bond exists in the α phase, but the bonding character of the Pd?H(D) bond in the α phase is quite different from that in the β phase; the nature of the Pd?H(D) bond in the α phase is a localized covalent bond whereas that in the β phase is a metallic bond.  相似文献   
993.
Herein, we report use of [Li+@C60]TFSI? as a dopant for spiro‐MeOTAD in lead halide perovskite solar cells. This approach gave an air stability nearly 10‐fold that of conventional devices using Li+TFSI?. Such high stability is attributed to the hydrophobic nature of [Li+@C60]TFSI? repelling moisture and absorbing intruding oxygen, thereby protecting the perovskite device from degradation. Furthermore, [Li+@C60]TFSI? could oxidize spiro‐MeOTAD without the need for oxygen. The encapsulated devices exhibited outstanding air stability for more than 1000 h while illuminated under ambient conditions.  相似文献   
994.
In native systems, scaffolding proteins play important roles in assembling proteins into complexes to transduce signals. This concept is yet to be applied to the assembly of functional transmembrane protein complexes in artificial systems. To address this issue, DNA origami has the potential to serve as scaffolds that arrange proteins at specific positions in complexes. Herein, we report that Kir3 K+ channel proteins are assembled through zinc‐finger protein (ZFP)‐adaptors at specific locations on DNA origami scaffolds. Specific binding of the ZFP‐fused Kir3 channels and ZFP‐based adaptors on DNA origami were confirmed by atomic force microscopy and gel electrophoresis. Furthermore, the DNA origami with ZFP binding sites nearly tripled the K+ channel current activity elicited by heterotetrameric Kir3 channels in HEK293T cells. Thus, our method provides a useful template to control the oligomerization states of membrane protein complexes in vitro and in living cells.  相似文献   
995.
Syntheses of epigallocatechin trimer, (epigallocatechin)2-epicatechin and (epigallocatechin)2-catechin were achieved. The key condensation to form the proanthocyanidin trimer derivatives was accomplished in a one-pot procedure using a dimeric epigallocatechin electrophile, which was prepared in situ by self-condensation of an epigallocatechin derivative, and an epigallocatechin, epicatechin, or catechin derivative as the nucleophile in the presence of a Lewis acid. The epigallocatechin monomer to trimer compounds containing a pyrogallol group significantly suppressed cell proliferation in PC-3 prostate cancer cells.  相似文献   
996.
Thallusin is the only known natural product that induces cell differentiation followed by formation of a thallus during the growth of green macroalgae such as Monostroma and Ulva. Herein, various thallusin analogues based on the terpen skeleton were synthesized to study the structure?activity relationships of thallusin. The potency of the synthetic analogues was investigated in an experimental assay, which demonstrated that the 19-methyl group in thallusin is essential for potent morphogenesis-inducing activity.  相似文献   
997.
We propose a new search algorithm to solve the equation for a fixed value of . By parametrizing min, this algorithm obtains and (if they exist) by solving a quadratic equation derived from divisors of . By using several efficient number-theoretic sieves, the new algorithm is much faster on average than previous straightforward algorithms. We performed a computer search for 51 values of below 1000 (except ) for which no solution has previously been found. We found eight new integer solutions for and in the range of .

  相似文献   

998.
It is well known that an association scheme with has at most two P-polynomial structures. The parametrical condition for an association scheme to have two P-polynomial structures is also known. In this paper, we give a similar result for Q-polynomial association schemes. In fact, if , then we obtain exactly the same parametrical conditions for the dual intersection numbers or Krein parameters.  相似文献   
999.
In this paper, we will propose an efficient heuristic algorithm for solving concave quadratic programming problems whose rank of the objective function is relatively small. This algorithm is a combination of Tuy's cutting plane to eliminate the feasible region and a kind of tabu-search method to find a good vertex. We first generate a set of V of vertices and select one of these vertices as a starting point at each step, and apply tabu-search and Tuy's cutting plane algorithm where the list of tabu consists of those vertices eliminated by cutting planes and those newly generated vertices by cutting planes. When all vertices of the set V are eliminated, the algorithm is terminated. This algorithm need not converge to a global minimum, but it can work very well when the rank is relatively small (up to seven). The incumbent solutions are in fact globally optimal for all tested problems. We also propose an alternative algorithm by incorporating Rosen's hyperrectangle cut. This algorithm is more efficient than the combination of Tuy's cutting plane and tabu-search.  相似文献   
1000.
Summary The method described consists in decomposing the silicate rock sample by fusion with sodium hydroxide or sodium hydroxide-peroxide, leaching the melt with water, evolving arsine from the filtrate, and finally determining arsenic by photometric evaluation of molybdenum blue. Satisfactory accuracy has been demonstrated for the range 0.0 to 20 p. p. m. As, for which the method is particularly intended.
Zusammenfassung Zur Bestimmung des Arsengehaltes in Silikatgesteinen wird die Probe durch Schmelzen mit Natriumhydroxyd und gegebenenfalls Natriumperoxyd aufgeschlossen. Aus dem Filtrat der wäßrigen Lösung dieser Schmelze wird Arsenwasserstoff entwickelt und in natriumhydrogenkarbonathältiger Jodlösung aufgefangen. Das hierbei entstehende Arsenat wird nach Zugabe von Molybdatreagens und Bisulfit photometrisch bestimmt. Für Arsengehalte unter 0,02% werden nach dieser Methode Resultate von zufriedenstellender Genauigkeit erhalten.

Résumé La méthode décrite consiste en la décomposition de l'échantillon de roche silicatée par fusion avec la soude ou le peroxyde de sodium, reprenant la partie fondue par l'eau, libérant l'hydrogène arsénié du filtrat et finalement dosant l'arsenic par colorimétrie du bleu de molybdène. Une précision suffisante a été mise en évidence dans le domaine de 0,0 à 20 p. p. m. d'arsenic pour lequel la méthode convient particulièrement bien.


Fulbright Scholar.  相似文献   
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