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71.
Shahram Mehdipour-Ataei Samal Babanzadeh 《International Journal of Polymer Analysis and Characterization》2020,25(3):147-157
AbstractA new monomeric building block was prepared via three consecutive reactions. 4-(4-Nitrobenzyl)pyridine was catalytically reduced to 4-(4-aminobenzyl)pyridine by converting the nitro to amino group. In second step, the later compound was reacted with 3,5-dinitrobenzoyl chloride to obtain a dinitro compound which finally was converted to a new diamine by reduction of nitro groups. Polycondensation reactions of the diamine with diacidchlorides led to preparation of novel cardo polyamides with high thermal stability and flame retardancy, as well as improved solubility. The structure-property relations were studied by varying the diacidchlorides to investigate the effect of symmetry and aromaticity on the polymers. 相似文献
72.
Ultrathin Mn Doped Ni-MOF Nanosheet Array for Highly Capacitive and Stable Asymmetric Supercapacitor
Dengchao Zheng Hao Wen Xun Sun Xin Guan Jie Zhang Wenli Tian Hao Feng Dr. Hongjing Wang Prof. Yadong Yao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(71):17149-17155
In this study, we demonstrate that an Mn-doped ultrathin Ni-MOF nanosheet array on nickel foam (Mn0.1-Ni-MOF/NF) serves as a highly capacitive and stable supercapacitor positive electrode. The Mn0.1-Ni-MOF/NF shows an areal capacity of 6.48 C cm−2 (specific capacity C: 1178 C g−1) at 2 mA cm−2 in 6.0 m KOH, outperforming most reported MOF-based materials. More importantly, it possesses excellent cycle stability to maintain 80.6 % capacity after 5000 cycles. An asymmetric supercapacitor device utilizing Mn0.1-Ni-MOF/NF as the positive electrode and activated carbon as the negative electrode attains a high energy density of 39.6 Wh kg−1 at 143.8 Wkg−1 power density with a capacitance retention of 83.6 % after 5000 cycles. 相似文献
73.
Chaonan Xie Qin Li Gang Han Huan Liu Jien Yang Jincheng Li 《Biomedical chromatography : BMC》2019,33(5)
Tricaine methanesulfonate is one of most commonly used anesthetics in fish during blood sampling, artificial propagation and long‐distance transportation. In this study, an accurate method for the quantitative determination of tricaine in fish samples by a stable isotope dilution assay coupled with high‐performance liquid chromatography–triple quadrupole mass spectrometry was developed. Tricaine‐D5 was synthesized and used as an isotopically labeled internal standard for the determination of tricaine. The analytical performance of the method was validated for tricaine determination in marine fish and freshwater fish. The determination of tricaine was linear in the range of 2.0–200.0 μg L?1. The limit of detection and limit of quantitation for fish muscle tissues were 1.0 and 4.0 μg kg?1, respectively. Good recoveries were obtained in the range of 92.08–97.50%. The inter‐ and intra‐assay relative standard deviations (RSD values) were investigated, and the values were 0.39–3.01 and 0.85–2.77%, respectively. The values of CCα and CCβ were 10.21–10.43 and 10.42–10.87 μg kg?1, respectively. The clearance of MS‐222 from grass carp was further studied using our method. The results demonstrate that MS‐222 could be well absorbed and rapidly eliminated after bath administration. 相似文献
74.
Yunshyong Chow 《Journal of Difference Equations and Applications》2013,19(2):169-187
We investigate asymptotic dynamics of the classical Leslie–Gower competition model when both competing populations are subject to Allee effects. The system may possess four interior steady states. It is proved that for certain parameter regimes both competing populations may either go extinct, coexist or one population drives the other population to extinction depending on initial conditions. 相似文献
75.
P. M. Zavlin D. A. Efremov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):247-250
Abstract Phosphoric anhydride interacts with different CH-, NH-, PH-, SH-acids with the formation of corresponding amidophosphates and esters. 相似文献
76.
S. Grethe S. Schrader A. Giesemann O. Larink H. J. Weigel 《Isotopes in environmental and health studies》2013,49(2-3):211-217
Abstract The effects of earthworm activity on the concentration and isotopic composition of total sulfur in soils was investigated using batch experiments. Two ecologically different lumbricid species, the anecic Lumbricus terrestris and the endogeic Aporrectodea caliginosa, were used. The earthworms were fed birch leaves, beech leaves, cattle manure or mixed plant litter. All food sources differed isotopically (δ34S) from the soil (Parabraunerde). As a reference, one experiment was carried out without additional food. The experimental results show, that both earthworm species influence the total S-content and the δ34S-values in the soil by digestion of the different food sources. The differences in the total S-content of the earthworm tissues and in the S-isotopic composition of the casts can be attributed to the ecological differences between the earthworm species. 相似文献
77.
Two types of sensitivities are proposed for statically stable sailcrafts.One type is the sensitivities of solar-radiation-pressure force with respect to position of the center of mass,and the other type is the sensitivities of solar-radiation-pressure force with respect to attitude.The two types of sensitivities represent how the solar-radiationpressure force changes with the position of mass center and the attitude.Sailcrafts with larger sensitivities undergo larger error of the solar-radiation-pressure force,leading to larger orbit error,as demonstrated by simulation.Then as a case study,detailed formulas are derived to calculate the sensitivities for sailcrafts with four triangular sails.According to these formulas,in order to reduce both types of sensitivities,the angle between opposed sails should not be too large,and the center of mass should be as close to the axis of symmetry of the four sails as possible and as far away from the center of pressure of the sailcraft as possible. 相似文献
78.
M. M. Sidky M. R. Mahran A. A. El-kateb I. T. Hennawy 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):409-412
Abstract Trialkyl phosphites react with quinisatin (1) and its monohydrate 3 to give the corresponding phosphate derivatives 2a-c. The same compounds are obtained upon reacting 1 and/or 3 with the proper dialkyl phosphite. Structural reasonings based on IR, MS and NMR spectral data, are presented. 相似文献
79.
Malek Taher Maghsoodlou Norollah Hazeri Ghafar Afshari Uranous Niroumand 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2681-2689
The reaction of triphenylphosphine with dialkyl acetylenedicarboxylates in the presence of a strong SH-acid or NH-acid, such as 2-mercaptobenzoxazole and 2-benzoxazolinone, has been studied. In some cases, stable phosphorus ylides are obtained in excellent yields. The ylide moiety of these compounds is strongly conjugated with the adjacent carbonyl group, and the rotation about the partial double bond in (E) and (Z) geometrical isomers is slow on the NMR time scale at an ambient temperature. Thus, these exist as a mixture of geometrical isomers. 相似文献
80.
A series of novel silicone modified polyurethane (Si-PU) surfactants were successfully synthesized by using hydroxypropyl-terminated polydimethylsiloxane (HPMS), polyethylene glycol (PEG), dimethylolpropionic acid (DMPA) and isophoronediisocyanate (IPDI). The chemical structure of the surfactant was confirmed by FTIR and 1H-NMR. TEM photographs showed that the micelles of the Si-PU surfactants dispersed in aqueous solution were spherical with the particle size in the range of 100–400 nm. Surface tension measurements indicated that these surfactants had low surface tension to 29.9 mN·m?1and a definite critical micelle concentration to, approximately 5.0×10?4–7.5×10?4mol·L?1. When the content of HPMS was 20 wt%, the surfactant's, emulsifying performance was superior to the traditionally available Span80/Tween80 mixed emulsifiers. In addition to that, no phase transition temperature was detected from 20°C to 90°C by fluorescence probe and DSC measurements, confirming the high thermal stability of the micelles. 相似文献