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301.
302.
We prove that a.a.s. as soon as a Kronecker graph becomes connected it has a finite diameter. 相似文献
303.
We study the logarithmic–exponential functional equation and check whether the alienation phenomenon takes place. 相似文献
304.
305.
Justyna Werner Karolina Kohut Robert Frankowski Agnieszka Zgoła-Grześkowiak 《Journal of separation science》2023,46(2):2200682
In this study, an efficient preconcentration method was presented that is based on dispersive liquid-liquid microextraction taking the advantage of newly synthesized phosphonium deep eutectic solvents used as extractants and ultrasound probe as a dispersing agent. The extracts obtained were analyzed by high-performance liquid chromatography. To optimize the five most important factors for the microextraction procedure a central composite design plan was used. Under optimal conditions (140 μl of extractant, 60 mg of NaCl, pH = 2.0, 120 s of extraction time with ultrasound probe as the dispersing agent, 16 min of centrifugation for phase separation), the proposed method allowed to achieve good precision with RSD between 3.2% and 9.7% at 1.0, 5.0 and 40.0 ng ml levels. The preconcentration factors were equal to 42, 39, and 41, and the limits of detection 0.128, 0.103, and 0.135 ng/ml for dicamba, 2-methyl-4-chlorophenoxyacetic acid, and 2-methyl-4-chlorophenoxypropionic acid, respectively. The proposed method was successfully applied for the determination of chlorophenoxy acid herbicides in water samples from drainage ditches with a good recovery in the range of 70%–93%. 相似文献
306.
Elvin V. Salerno Dr. Justyna Zeler Dr. Svetlana V. Eliseeva Dr. Miguel A. Hernández-Rodríguez Dr. Albano N. Carneiro Neto Prof. Dr. Stéphane Petoud Prof. Dr. Vincent L. Pecoraro Prof. Dr. Luís D. Carlos 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(61):13792-13796
Nanothermometry is the study of temperature at the submicron scale with a broad range of potential applications, such as cellular studies or electronics. Molecular luminescent-based nanothermometers offer a non-contact means to record these temperatures with high spatial resolution and thermal sensitivity. A luminescent-based molecular thermometer comprised of visible-emitting Ga3+/Tb3+ and Ga3+/Sm3+ metallacrowns (MCs) achieved remarkable relative thermal sensitivity associated with very low temperature uncertainty of Sr=1.9 % K−1 and δT<0.045 K, respectively, at 328 K, as an aqueous suspension of polystyrene nanobeads loaded with the corresponding MCs. To date, they are the ratiometric molecular nanothermometers offering the highest level of sensitivity in the physiologically relevant temperature range. 相似文献
307.
This work presents a new ultra‐sensitive method of Al(III) as Al‐cupferron complex voltammetric determination, in 0.04 M ammonium sulfate of pH=6.1 and 0.003 M cupferron by environmentally friendly and durable Bismuth Bulk Annular Band Electrode (BiABE). The optimal measuring parameters include: potential window from ?700 to ?1250 mV versus Ag|AgCl, preconcentration time and potential of 120 s, ?700 mV, respectively. The electrode surface can be activated by fast in situ method: applying short conditioning by the potential of ?1300 mV. The best obtained analytical parameters are: range of linearity 0.2–1.2 μg L?1 with high sensitivity of 1.333 μA/μg L?1, limit of detection 0.04 μg L?1 and repeatability below 2.3 %. The described procedure was verified using various CRMs, i. e. surface waters, waste waters and tea leaves. Satisfactory recovery values were obtained in the interval 99.2–103.5 %. Developed DPV procedure was used to determine Al in tap and natural waters in aspect of recovery of aluminum, which was added to the samples. For the first time, we tested also Al removal efficiency from water by the water filters mounted in the trip bottle. 相似文献
308.
Ewa esawska Justyna Kalinowska-Tucik Wojciech Nitek Henryk Marona Anna M. Waszkielewicz 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(1):30-36
Aminoalkanol derivatives have attracted much interest in the field of medicinal chemistry as part of the search for new anticonvulsant drugs. In order to study the influence of the methyl substituent and N‐oxide formation on the geometry of molecules and intermolecular interactions in their crystals, three new examples have been prepared and their crystal structures determined by X‐ray diffraction. 1‐[(2,6‐Dimethylphenoxy)ethyl]piperidin‐4‐ol, C15H23NO2, 1 , and 1‐[(2,3‐dimethylphenoxy)ethyl]piperidin‐4‐ol, C15H23NO2, 2 , crystallize in the orthorhombic system (space groups P212121 and Pbca, respectively), with one molecule in the asymmetric unit, whereas the N‐oxide 1‐[(2,3‐dimethylphenoxy)ethyl]piperidin‐4‐ol N‐oxide monohydrate, C15H23NO3·H2O, 3 , crystallizes in the monoclinic space group P21/c, with one N‐oxide molecule and one water molecule in the asymmetric unit. The geometries of the investigated compounds differ significantly with respect to the conformation of the O—C—C linker, the location of the hydroxy group in the piperidine ring and the nature of the intermolecular interactions, which were investigated by Hirshfeld surface and corresponding fingerprint analyses. The crystal packing of 1 and 2 is dominated by a network of O—H…N hydrogen bonds, while in 3 , it is dominated by O—H…O hydrogen bonds and results in the formation of chains. 相似文献
309.
The 1H, 13C, 15N,and 19F NMR chemical shifts assignments in 5,10,15‐tris (pentafluorophenyl)tetra–15N corrole at 191 K 下载免费PDF全文
310.
Justyna Krajenta Andrzej Pawlak Andrzej Galeski 《Journal of Polymer Science.Polymer Physics》2016,54(19):1983-1994
It was shown that a solid‐state deformation of polypropylene (PP) being in the form of partially disentangled powder is possible by blending with another molten polymer. During mixing of disentangled polypropylene powder with polystyrene at the temperature below melting of polypropylene crystals the shear forces deform powder grains into nanofibers. All disentangled powder particles larger than 0.7 µm underwent deformation into nanofibers having the mean thickness between 100 and 200 nm. Polypropylene nanofibers got entangled during blending and form a network within polystyrene matrix, reinforcing it. Network of entangled nanofibers can be further deformed with pronounced strain hardening and strength reaching 70 MPa at 135 °C. Blending resulted in generation of PP nanofibers and formation of PP nanofibers entangled network, thus formation of “all‐polymer nanocomposites” in one step compounding. The crucial feature for ultra‐deformation of PP grains by shearing during mixing is disentanglement of macromolecules. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1983–1994 相似文献