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131.
An open metal site framework named UTSA‐16 was synthesized and modified as a high‐capacity adsorbent for reversible CO2 capture. Partial substitution of intrinsic Co2+ sites of UTSA‐16 with Ni2+ centres was realized in the molar composition range 0–75% Ni with the aim of increasing CO2 uptake. Synthesized bimetallic Nix‐UTSA‐16 (x = 0, 20, 50, 75) materials were characterized using various techniques to assess the influence of chemical composition on CO2 binding affinity and any subsequent physical change in morphology, crystal size and porosity on the total uptake. Experimental isotherm adsorption studies showed the following trend for CO2 adsorption capacity employing the Nix‐UTSA‐16 series: Ni20‐UTSA‐16 > UTSA‐16 > Ni50‐UTSA‐16 > Ni75‐UTSA‐16. According to the dynamic breakthrough CO2 profiles measured for a mixture of CO2 and CH4 (15/85 molar ratio), Ni20‐UTSA‐16 exhibited 2 times the breakthrough time with 1.5 times the loading capacity at 75 Nml min?1 feed flow rate, compared to the parent UTSA‐16. In addition, the Ni20‐UTSA‐16 bimetallic metal–organic framework exhibited lower isosteric heat of adsorption compared to UTSA‐16 (ΔHave = 28.54 versus 46.85 kJ mol?1). As a result, more than 95% of its capacity was restored by applying a partial vacuum for only 1 h at room temperature without involving any other time‐ and energy‐consuming regenerative step. 相似文献
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We consider the question of existence of positive solutions for a class of elliptic problems in all of having a noncoercive linear part and a sign-changing nonlinearity of the form .
Received December 20, 1999 / Accepted July 17, 2000 /Published online November 9, 2000 相似文献
135.
Ali Pourjavadi Zahra Mazaheri Tehrani Alireza Shakerpoor 《Supramolecular chemistry》2016,28(7-8):624-633
In the present research, two types of drug carriers based on mesoporous silica-coated magnetic graphene oxide, Fe3O4@GO@mSiO2, were synthesised and the pH-responsive behaviour for doxorubicin release was investigated. One type of the carrier was dendrimer-like multi ethylene amine grafted on Fe3O4@GO@mSiO2 and the other was dendrimer-like supramolecular polypseudorotaxane. Herein, α-cyclodextrin was used in the structure of supramolecular nanoparticles as a gatekeeper to inhibit the drug from escaping at neutral pH (the pH of healthy tissue). The drug release profile showed that the supramolecular nanocarrier was more sensitive to the pH changes. The content of drug release was about 100% at pH 5.5 (endosomal pH) during 48 h; but it was zero at pH 7.4. Also, the dendrimer structure facilitated the triggered release of doxorubicin. 相似文献
136.
Elham Oveili Shohreh Jahani Omid Tayari Abbas Jahanara Zohreh Fazli Zahra Aramesh-Boroujeni Soroush Rashidi Nadia Rezaei Zade Baravati Mohammad Mehdi Foroughi 《Electroanalysis》2023,35(7):e202200432
The current work aimed to fabricate a new cocaine sensor of octahedral palladium-doped cobaltite composite (Oh-Pd2+ : Co3O4-C) using a simple hydrothermal protocol. As-fabricated cocaine sensing approach was validated by various methods. Energy dispersive X-ray analysis, X-ray diffraction and scanning electron microscopy were recruited to characterize our charged modified composite. The electrode could sensitively detect cocaine, with a lengthy linear range (0.01 μM–900.0 μM) and a limit of detection (1.3 nM). The quantitative cocaine determination was achieved in the biological specimens using our modified electrode, the results of which displayed admirable outcomes. 相似文献
137.
Carsten E. Seyfert Christoph Porten Dr. Biao Yuan Selina Deckarm Dr. Fabian Panter Dr. Chantal D. Bader Janetta Coetzee Felix Deschner Dr. Kamaleddin H. M. E. Tehrani Prof. Dr. Paul G. Higgins Prof. Dr. Harald Seifert Prof. Dr. Thomas C. Marlovits Dr. Jennifer Herrmann Prof. Dr. Rolf Müller 《Angewandte Chemie (International ed. in English)》2023,62(2):e202214094
Over recent decades, the pipeline of antibiotics acting against Gram-negative bacteria is running dry, as most discovered candidate antibiotics suffer from insufficient potency, pharmacokinetic properties, or toxicity. The darobactins, a promising new small peptide class of drug candidates, bind to novel antibiotic target BamA, an outer membrane protein. Previously, we reported that biosynthetic engineering in a heterologous host generated novel darobactins with enhanced antibacterial activity. Here we utilize an optimized purification method and present cryo-EM structures of the Bam complex with darobactin 9 (D9), which served as a blueprint for the biotechnological generation of twenty new darobactins including halogenated analogs. The newly engineered darobactin 22 binds more tightly to BamA and outperforms the favorable activity profile of D9 against clinically relevant pathogens such as carbapenem-resistant Acinetobacter baumannii up to 32-fold, without observing toxic effects. 相似文献
138.
Reaction of 2-fluoroaziridines with potassium alkynyltrifluoroborates in the presence of BF3·OEt2 leads to fluorinated propargyl amines in moderate to good yields. The reaction proceeds as an in situ isomerization of 2-fluoroaziridines to α-fluorinated imines, followed by the reaction of the imine with alkynyldifluoroborane, which is generated in situ from the potassium alkynyltrifluoroborates and BF3·OEt2. 相似文献
139.
Deactivation studies of bifunctional Fe-HZSM5 catalyst in Fischer-Tropsch process 总被引:1,自引:0,他引:1
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Ali Nakhaei Pour Seyed Mehdi Kamali Shahri Yahya Zamani Mohammad Irani Shohreh Tehrani 《天然气化学杂志》2008,17(3):242-248
A physical mixture of alkali-promoted iron catalyst with binder based on Fischer-Tropsch synthesis and an acidic co-catalyst (HZSM5) for syngas conversion to hydrocarbons was studied in a fixed bed micro reactor. Deactivation data were obtained during the synthesis over a 1400 h period. The deactivation studies on iron catalyst showed that this trend followed the phase transformation Fe2.2C ( ε′) → Fe5C2 (χ) → Fe3C (θ), and the final predominant phase of the catalyst was Fe3C (θ). Deactivation of zeolite component in bifunctional catalyst may be caused by coking over the zeolitic component, dealumination of zeolite crystals, and migration of alkali promoters from iron catalyst under synthesis conditions. The deactivation rate of iron catalyst was also obtained. 相似文献
140.