Reactions of <i>m</i>- and <i>p</i>-Divinylbenzene−Diiron Hexacarbonyl with Aryllithium Reagents. Crystal Structures of [(CO)₃Fe(<i>m</i>-C₁₀H₁₀)(CO)₂FeC(OC₂H₅)C₆H₄CH₃-<i>o</i>] and [(CO)₃Fe(<i>p</i>-C₁₀H₁₀)(CO)₂FeC(OC₂H₅)C₆H₄CF₃-<i>p</i>]^†

The reactions of m-divinylbenzene−diiron hexacarbonyl (1) with aryllithium reagents, ArLi (Ar = C6H5, o-, m-, p-CH3C6H4, p-CH3OC6H4, p-CF3C6H4, m-ClC6H4), in ether at low temperature gave acylmetalate intermediates followed by alkylation with Et3OBF4 in aqueous solution at 0 °C to afford the isomerized divinylbenzene-coordinated alkoxycarbene complexes [(CO)3Fe(m-C10H10)(CO)2FeC(OC2H5)Ar] (3, Ar = C6H5; 4, Ar = o-CH3C6H4; 5, Ar = m-CH3C6H4; 6, Ar = p-CH3C6H4; 7, Ar = p-CH3OC6H4; 8, Ar = p-CF3C6H4; 9, Ar = m-ClC6H4) with two types of structures. The p-divinylbenzene-diiron hexacarbonyl (2) also reacted with the aryllithium reagents under the same conditions to give the corresponding isomerized alkoxycarbene complexes [(CO)3Fe(p-C10H10)(CO)2FeC(OC2H5)Ar] (10, Ar = C6H5; 11, Ar = o-CH3C6H4; 12, Ar = m-CH3C6H4; 13, Ar = p-CH3C6H4; 14, Ar = p-CH3OC6H4; 15, Ar = p-CF3C6H4; 16, Ar = m-ClC6H4). The structures of complexes 4 and 15 have been determined by single-crystal X-ray diffraction studies

Macrocarbocycle Synthesis by Copper- and Silver-Mediated Cyclization of Tethered Cyclopropenone Acetals. Electronic Tuning of Metal Vinylcarbene Complex into Vinylmetallic Species

Synthesis of n-membered medium and macrocarbocycles through intramolecular sp2−sp2 C−C bond formation was achieved with the aid of CuOTf or AgOTf by intramolecular coupling reaction of cyclopropenone acetals tethered by a methylene chain of (n − 4) carbon atoms. The reaction has proved to be useful for the synthesis of large carbocycles (n > 13) in yields as high as 78%, and most notably also for an eight-membered carbocycle in 88% yield

Synthesis and Properties of a Photopolymerizable Carbene-Mediated Poly Phosphinate Flame Retardant by Carbene Polymerization

A novel photopolymerizable poly phosphinate (poly ethyl (4-acrylamidebenzyl)­phosphinate, P-NH-AC) flame retardant was synthesized by a carbene polymerization and characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and gel permeation chromatography (GPC). The effect of P-NH-AC on the kinetics of photopolymerization, thermal stability, combustion behaviors, and physical and mechanical properties of the UV-cured materials were investigated by real-time infrared spectroscopy (RT-IR), thermogravimetric analysis (TGA), thermogravimetric analysis/infrared spectrometry (TGA-IR), the limiting oxygen index (LOI), and the cone calorimetric test (CCT). For the systems with P-NH-AC, the thermal stability was improved with the increase of the P-NH-AC; however, the final residue of all systems was low. The addition of 5% P-NH-AC increased the LOI from 29.0 to 32.0. The addition of P-NH-AC significantly decreased the heat release rate (HRR), total heat release (THR), and total smoke production (TSP) of the resin. Moreover, P-NH-AC can also improve physical and mechanical properties of the materials

Outsourced Data Integrity Checking with Practical Key Update in Edge-Cloud Resilient Networks

The edge-cloud continuum is an advanced paradigm for cloud computing, which brings data storage and compute power closer to users or devices, and as a result, eliminates lag time and saves bandwidth. However, this new paradigm is harsh for secure storage and computation due to the separation of data ownership and control. Data security, especially outsourced data integrity in the edge-cloud resilient network, becomes one of the most fundamental challenges. To check the outsourced data integrity and address the efficient key update issue in this scenario, in this article, we propose a framework of outsourced data integrity checking with a practical key update in the edge-cloud resilient network. We first review the existing outsourced data integrity checking algorithms and then put forward a potential solution to achieving outsourced data integrity checking with a practical key update, which is composed of three phases, namely key request and update, local data upload, and outsourced data integrity auditing. We implement a prototype system for our proposal as well, which demonstrates its practicality

Load-axial displacement curve.

To enhance the concrete confinement ability of circular-ended aluminum alloy tubes, carbon fiber reinforced polymer (CFRP) was bonded onto the tube surface to form CFRP confined concrete columns with circular ends (RCFCAT). Eight specimens were designed with number of CFRP layers and section aspect ratio as variables. Axial loading test and finite element analysis were carried out. Results showed CFRP delayed buckling of the aluminum alloy tube flat surfaces, transforming inclined shear buckling failure into CFRP fracture failure. Specimens with aspect ratio above 4 experienced instability failures. Under same cross-section, CFRP increased axial compression bearing capacity and ductility by up to 30.8% and 43.4% respectively. As aspect ratio increased, enhancement coefficients of bearing capacity and ductility gradually decreased, the aspect ratio is restrictive when it is less than 2.5. CFRP strengthening increased initial axial compression stiffness of specimens by up to 117.9%. The stiffness decreased gradually with increasing aspect ratio, with most significant increase at aspect ratio of 4. Strain analysis showed CFRP bonding remarkably reduced circumferential and longitudinal strains. Confinement effect was optimal at aspect ratio around 2.0. The rationality of the refined FE model established has been verified in terms of load displacement curves, capturing circular aluminum tube oblique shear buckling, concrete "V" shaped crushing, and CFRP tearing during specimen failure. The parameter analysis showed that increasing the number of CFRP layers is one of the most effective methods for improving the ultimate bearing capacity of RCFCAT.</div

Load-displacement curve for parameter analysis.

To enhance the concrete confinement ability of circular-ended aluminum alloy tubes, carbon fiber reinforced polymer (CFRP) was bonded onto the tube surface to form CFRP confined concrete columns with circular ends (RCFCAT). Eight specimens were designed with number of CFRP layers and section aspect ratio as variables. Axial loading test and finite element analysis were carried out. Results showed CFRP delayed buckling of the aluminum alloy tube flat surfaces, transforming inclined shear buckling failure into CFRP fracture failure. Specimens with aspect ratio above 4 experienced instability failures. Under same cross-section, CFRP increased axial compression bearing capacity and ductility by up to 30.8% and 43.4% respectively. As aspect ratio increased, enhancement coefficients of bearing capacity and ductility gradually decreased, the aspect ratio is restrictive when it is less than 2.5. CFRP strengthening increased initial axial compression stiffness of specimens by up to 117.9%. The stiffness decreased gradually with increasing aspect ratio, with most significant increase at aspect ratio of 4. Strain analysis showed CFRP bonding remarkably reduced circumferential and longitudinal strains. Confinement effect was optimal at aspect ratio around 2.0. The rationality of the refined FE model established has been verified in terms of load displacement curves, capturing circular aluminum tube oblique shear buckling, concrete "V" shaped crushing, and CFRP tearing during specimen failure. The parameter analysis showed that increasing the number of CFRP layers is one of the most effective methods for improving the ultimate bearing capacity of RCFCAT.</div

Failure mode.

To enhance the concrete confinement ability of circular-ended aluminum alloy tubes, carbon fiber reinforced polymer (CFRP) was bonded onto the tube surface to form CFRP confined concrete columns with circular ends (RCFCAT). Eight specimens were designed with number of CFRP layers and section aspect ratio as variables. Axial loading test and finite element analysis were carried out. Results showed CFRP delayed buckling of the aluminum alloy tube flat surfaces, transforming inclined shear buckling failure into CFRP fracture failure. Specimens with aspect ratio above 4 experienced instability failures. Under same cross-section, CFRP increased axial compression bearing capacity and ductility by up to 30.8% and 43.4% respectively. As aspect ratio increased, enhancement coefficients of bearing capacity and ductility gradually decreased, the aspect ratio is restrictive when it is less than 2.5. CFRP strengthening increased initial axial compression stiffness of specimens by up to 117.9%. The stiffness decreased gradually with increasing aspect ratio, with most significant increase at aspect ratio of 4. Strain analysis showed CFRP bonding remarkably reduced circumferential and longitudinal strains. Confinement effect was optimal at aspect ratio around 2.0. The rationality of the refined FE model established has been verified in terms of load displacement curves, capturing circular aluminum tube oblique shear buckling, concrete "V" shaped crushing, and CFRP tearing during specimen failure. The parameter analysis showed that increasing the number of CFRP layers is one of the most effective methods for improving the ultimate bearing capacity of RCFCAT.</div

Evaluation of the bicortical screws.

Evaluation of the bicortical screws.</p

Construction of round-ended section.

To enhance the concrete confinement ability of circular-ended aluminum alloy tubes, carbon fiber reinforced polymer (CFRP) was bonded onto the tube surface to form CFRP confined concrete columns with circular ends (RCFCAT). Eight specimens were designed with number of CFRP layers and section aspect ratio as variables. Axial loading test and finite element analysis were carried out. Results showed CFRP delayed buckling of the aluminum alloy tube flat surfaces, transforming inclined shear buckling failure into CFRP fracture failure. Specimens with aspect ratio above 4 experienced instability failures. Under same cross-section, CFRP increased axial compression bearing capacity and ductility by up to 30.8% and 43.4% respectively. As aspect ratio increased, enhancement coefficients of bearing capacity and ductility gradually decreased, the aspect ratio is restrictive when it is less than 2.5. CFRP strengthening increased initial axial compression stiffness of specimens by up to 117.9%. The stiffness decreased gradually with increasing aspect ratio, with most significant increase at aspect ratio of 4. Strain analysis showed CFRP bonding remarkably reduced circumferential and longitudinal strains. Confinement effect was optimal at aspect ratio around 2.0. The rationality of the refined FE model established has been verified in terms of load displacement curves, capturing circular aluminum tube oblique shear buckling, concrete "V" shaped crushing, and CFRP tearing during specimen failure. The parameter analysis showed that increasing the number of CFRP layers is one of the most effective methods for improving the ultimate bearing capacity of RCFCAT.</div

Inserted screw angle.

(XLSX)</p