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151.
Lan Lei Xianya Geng Shuchao Li Yingjun Peng Yuantian Yu 《International journal of quantum chemistry》2019,119(24):e26044
Let denote a molecular graph of linear [n] phenylene with n hexagons and n squares, and let the Möbius phenylene chain be the graph obtained from the by identifying the opposite lateral edges in reversed way. Utilizing the decomposition theorem of the normalized Laplacian characteristic polynomial, we study the normalized Laplacian spectrum of , which consists of the eigenvalues of two symmetric matrices ℒ R and ℒ Q of order 3n. By investigating the relationship between the roots and coefficients of the characteristic polynomials of the two matrices above, we obtain an explicit closed-form formula of the multiplicative degree-Kirchhoff index as well as the number of spanning trees of . Furthermore, we determine the limited value for the quotient of the multiplicative degree-Kirchhoff index and the Gutman index of . 相似文献
152.
Shilin Jiang Dr. Jianhui Lan Dr. Lin Wang Dr. Yalan Liu Yuke Zhong Yichuan Liu Dr. Liyong L.-Y. Yuan Dr. Lirong Zheng Prof. Zhifang Chai Prof. Weiqun Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(45):11721-11729
Molten salt electrolysis is a vital technique to produce high-purity lanthanide metals and alloys. However, the coordination environments of lanthanides in molten salts, which heavily affect the related redox potential and electrochemical properties, have not been well elucidated. Here, the competitive coordination of chloride and fluoride anions towards lanthanide cations (La3+ and Nd3+) is explored in molten LiCl-KCl-LiF-LnCl3 salts using electrochemical, spectroscopic, and computational approaches. Electrochemical analyses show that significant negative shifts in the reduction potential of Ln3+ occur when F− concentration increases, indicating that the F− anions interact with Ln3+ via substituting the coordinated Cl− anions, and confirm [LnClxFy]3−x−y (ymax=3) complexes are prevailing in molten salts. Spectroscopic and computational results on solution structures further reveal the competition between Cl− and F− anions, which leads to the formation of four distinct Ln(III) species: [LnCl6]3−, [LnCl5F]3−, [LnCl4F2]3− and [LnCl4F3]4−. Among them, the seven-coordinated [LnCl4F3]4− complex possesses a low-symmetry structure evidenced by the pattern change of Raman spectra. After comparing the polarizing power (Z/r) among different metal cations, it was concluded that Ln−F interaction is weaker than that between transition metal and F− ions. 相似文献
153.
154.
Wang Hong Cai Le He Shu-Hua Zheng Xiao-Bei Liu Yu-Xia Zhang Lan 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(6):2553-2559
Journal of Radioanalytical and Nuclear Chemistry - Prostate-specific membrane antigen (PSMA) is a biomarker for prostate cancer, which is commonly used in the development of diagnostic and... 相似文献
155.
Forest product trade plays an important role in the development of the Chinese forest industry. The trading value of forest product has shown a yearly growth rate of 12% during the last five recent years. Stringent environmental regulations in China have a profound impact on raw material supplies and industrial production in the forest sector; however, their impact on the forest product trade is still unclear. This study applies fixed and random effects models as well as a seemingly unrelated regression model to investigate the impact of environmental regulations on the trade of forest product from 2002 to 2015. The results indicate that the stringent environmental regulations promoted the import but restricted the export of forest product in general. Specifically, the stringent environmental regulations stimulated the import but had an ambiguous impact on the export of the paper product. The stringent environmental regulations had also stimulated the import of wood product but inhibited the export. In contrast, wooden furniture had been affected minimally; only export got slightly negatively affected by environmental regulations. Recommendations for resource managers:
- Trade‐offs between economic growth and environmental regulations are needed to smoothly promote the forest product trade in China.
- Paper and wooden furniture product sectors are less likely to be affected by stringent environmental regulations, because high value‐added products could compensate for environmental costs.
- The wood product sector is more likely to be negatively affected by stringent environmental regulations because environmental costs could severely impact the competitiveness of low value‐added products.
156.
Haijing Liang Lixia Ma Changwei Li Qiang Peng Zhaoyan Wang Zhan-xin Zhang Lan Yu Huanxiang Liu Fengli An Weihua Xue 《Tetrahedron letters》2019,60(1):84-87
Glycosylation reactions are significant as they provide access to model compounds that are useful for elucidating biochemical pathways. Herein, we describe the development of glycosyl ortho-alkynylbenzoates as novel, bench-top stable, and readily available glycosyl donors. Glycosylation is promoted by inexpensive trimethylsilyl triflate (TMSOTf) in combination with N-iodosuccinimide (NIS) under mild reaction conditions; hence, the novel glycosyl donors are promising reagents for the synthesis of glycosides. 相似文献
157.
158.
This study investigated the possibility of substituting petroleum-based polymers with biopolymers for films and paper coatings. Arabinoxylan (AX) was extracted from distillers’ grains, a low-value corn ethanol byproduct, and modified through crosslinking with glutaraldehyde (GA) which was made into films and paper coatings. The effects of degree of substitution (DS) on film and coating properties of GA cross-linked AX, referred to as GAX, were investigated. The GAX films had markedly higher tensile strength, approximately 3 times higher than the unmodified AX films at low DS, with higher DS causing a negative effect on the film tensile strength. Compared to unmodified AX coating, paper coated with GAX also had significantly higher tensile index, presumably due to high adhesion between the coating and paper interface. When used as a coating binder with calcium carbonate pigments, GAX showed comparable performance to polyvinyl alcohol, a common industrial binder, demonstrating the potential to be substituted for the petroleum-based paper coating binder. 相似文献
159.
Dr. Honghong Gong Yu Gu Yucheng Zhao Qinzhi Quan Shantao Han Prof. Dr. Mao Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(2):929-937
Ultra-high-molecular-weight (UHMW) polymers display outstanding properties and hold potential for wide applications. However, their precise synthesis remains challenging. Herein, we developed a novel reversible-deactivation radical polymerization based on the strong and selective fluorine–fluorine interaction, allowing chain-transfer agents to spontaneously differentiate into two groups that take charge of the chain growth and reversible deactivation of the growing chains, respectively. This method enables dramatically improved livingness of propagation, providing UHMW polymers with a surprisingly narrow molecular weight distribution (Đ≈1.1) from a variety of fluorinated (meth)acrylates and acrylamide at quantitative conversions under visible-light irradiation. In situ chain-end extensions from UHMW polymers facilitated the synthesis of well-defined block copolymers, revealing the excellent chain-end fidelity achieved by this method. 相似文献
160.
Three one-dimensional ladder-like coordination polymers consisting of Cd6 metalloring as the building unit, {[Cd4LCl4]·3H2O}n ( 1 ), {[Cd3L(ClO4)(H2O)]ClO4·3H2O}n ( 2 ), and {[Cd6(L)2(NO3)2(CH3OH)(H2O)](NO3)2·2CH3OH·5H2O}n ( 3 ), were solvothermally constructed from a carboxylic functionalized bisazamacrocyclic ligand 4,4′-bis((4,7-bis(2-carboxyethyl)-1,4,7-triazacyclonon-1-yl)methyl)-1,1′-biphenyl (H4L). These compounds dispersed in ethanol show the multiple emissions originating from the monomeric and intramolecularly overlapping biphenyl moieties which could be sensitively quenched by picric acid (PA) and 4-nitrophenol (4-NP) through the effective fluorescence resonance energy transfer process. The differential fluorescent responses of each compound on exposure to PA and 4-NP individually make the convenient ratiometric discrimination of two analytes based on the fluorescent intensity ratio (I320/I360) attainable, and 1 and 2 as ratiometric chemosensors for PA present a broad linear detection range from 4 to 300 μM with detection limits of 0.84 and 0.93 μM, respectively. Furthermore, the blue light emission of 1 under an ultraviolet lamp could be selectively quenched by PA even in the presence of all other interfering nitroaromatic pollutants, which empowers the fast visual detection of PA by naked eye. 相似文献