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A rapid construction of enantioenriched benzofurochromanes was developed by SaBOX/copper(II) catalyzed enantioselective [3 + 2] annulation of γ-chromenes with quinones. This process takes advantage of the simple starting materials and a highly efficient chiral SaBOX/copper(II) catalyst system, leading to a variety of benzofurochromanes in up to 96% yield with up to 97% ee.

A dual-functional fluorescent probe based on coumarin fluorophore for monitoring ClO - and Cu 2+ was synthesized and characterized. The identification mechanisms for ClO - and Cu 2+ induced different colorimetric and ratiometric changes. ClO - caused a colorimetric change from yellow to colorless and 120 nm blue-shifted emission spectra from red to blue. Besides, Cu 2+ induced a remarkable fluorescence quenching behavior and 36 nm blue-shifted absorption spectra accompanied by the color change from yellow to luminous yellow. As expected, Probe 1 displayed excellent selectivity and sensitivity for detecting ClO - and Cu 2+ over other competing ions in their respective systems. The limits of detection for ClO - and Cu 2+ were 24.62 nM and 0.39 nM, respectively. The recognition mechanisms were proved by 1 H NMR, mass spectrum and theoretical calculations. More importantly, the reversibility of Cu 2+ could be applicable to rapid quantification for ClO - /Cu 2+ . Thus, the strategy for sensing ClO - /Cu 2+ was carried out, which revealed broad applications of Probe 1 in multiple actual water and biology., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Here, a conduction micropump with symmetric planar electrode pairs prepared on flame-retardant glass-reinforced epoxy (FR-4) copper-clad laminate (CCL) is fabricated. It is used to investigate the influence of chamber dimensions on the performance of a conduction micropump and to determine the reliability of the conduction pump when acetone is used as the working fluid. A testing platform is set up to evaluate conduction micropump performance under different conditions. When the chamber height is 0.2 mm, the pump pressure reaches its peak value.

A direct asymmetric dearomative amination of tryptamines with O-(2,4-dinitrophenyl)hydroxylamine (DPH) was achieved using CuBr-bisoxazoline complex as a catalyst, affording 3a-amino-pyrroloindolines in good to excellent enantioselectivity under mild reaction conditions. Furthermore, the synthetic value of this method was demonstrated in the total synthesis of (-)-psychotriasine in a highly concise manner., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Ultra-thin vapor chambers (UTVCs) are widely used to cool high-power electronics due to their excellent thermal conductivity. In this study, a UTVC of 82 mm × 58 mm × 0.39 mm with composite wick was prepared. The composite wick is composed of two layers of copper mesh and multiple spiral-woven meshes (SWMs), and the composite wick was applied in UTVC to improve liquid replenishment performance and temperature uniformity. Furthermore, the thermal performance of UTVCs with different support column diameters, filling ratios (FRs), and SWM structures was experimentally studied. The results found that the equivalent thermal conductivity (ETC) decreases as the diameter of the support column increases; the UTVC with 0.5 mm support column diameter has the highest ETC, at 3473 W/(m·K). Then, the effect of FR on the heat transfer performance of UTVCs with SWM numbers of 0, 1, 2, and 3 (0 SWMs, 1 SWM, 2 SWMs, 3 SWMs) is consistent, the 30% FR UTVC with 3 SWMs having the highest ETC, at 3837 W/(m·K). Finally, the increased number of SWMs can significantly improve the ultimate power of the UTVCs, the UTVC with 3 SWMs having the highest ultimate power, at 26 W. The above experimental studies indicate that the designed and manufactured UTVCs have great potential advantages in thermal dissipation for electronics. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: A copper catalyzed enantioselective [3+2] annulation of donor‐acceptor cyclopropanes with cyclic ketones has been developed, providing a concise protocol to enantioenriched 1‐oxaspiro[4.5]decanes in up to 98% yield with up to >99/1 dr and up to 92% ee. In addition, this method also provides a facile access to the enantioselective desymmetrisation of various 4‐substituted cyclohexanones. The resulting products were easily converted to the core structures of two natural products Heliespirones A and halogenated sesquiterpene isolated from L. saitoi. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: A copper catalyzed stereoselective [2+2] cyclization has been developed, providing a concise protocol to the direct construction of diaryl‐substituted cyclobutanes in up to 99% yield with up to >95/5 dr. Meanwhile, the enantioselective version of this reaction has also been achieved, leading to a series of optically active diaryl‐substituted cyclobutanes with up to 94% ee. [ABSTRACT FROM AUTHOR]

A highly diastereoselective copper‐catalyzed multicomponent cyclization of exocyclic enol ethers/enamines with methylene malonate and aldehydes has been developed to furnish spiroheterocyclic tetrahydropyrans in high yields with greater than 95:5 d.r. This method is practical, in that 36 examples, including a range of aldehydes and exo‐vinyl heterocycles, are presented. By applying the newly developed method, the total synthesis of (+)‐broussonetine G and formal synthesis of (+)‐broussonetine H were achieved in a concise way. [ABSTRACT FROM AUTHOR]

This paper presents a novel method combining the preforming and multi-tooth plowing processes to fabricate aluminum-based ultrathin flat heat pipes (UTFHPs). The use of a preforming process makes it more effective to machine arrayed microgrooves on the inner wall of UTFHPs. The multi-tooth plowing process helps greatly increase the capillary pressure and hydrophilicity of the heat pipe wick. The morphologies of the wick structures are characterized and a self-designed experimental platform is constructed to investigate the thermal performances of UTFHP samples under incremental heat loads. The results indicate that the multi-tooth plowing process is able to significantly reduce the minimum thermal resistance of the heat pipe by 83%. The thermal resistance of the UTFHP with a unilateral porous wick is smaller than that based on a central porous wick at the same liquid filling rate. The UTFHP has excellent radial temperature uniformity with the minimum radial temperature difference of 1.2 °C, because the structures made by multi-tooth plowing can effectively reduce the temperature difference. [ABSTRACT FROM AUTHOR]

Abstract: A facile and efficient method to produce optically pure benzofuroindolines, especially those without 3‐substituents that are susceptible to rearomatization, through [3+2] annulation of indoles with quinones is described. The suitable combination of a BOX ligand CuII hydrate complex and freshly activated molecular sieves functions to give controllably dynamic release of water, which enables the success of this reaction. This reaction can be performed on a gram scale with only 0.5 mol % catalyst loading. [ABSTRACT FROM AUTHOR]

Copper catalyzed enantioselective [4 + 2] annulations of D-A cyclobutanes and aldehydes have been developed. In the presence of a side arm modified chiral bisoxazoline (SaBOX) ligand, the [4 + 2] annulations proceeded smoothly with a broad substrate scope. 22 examples were studied, leading to the corresponding products with various functional groups in 41%-99% yields with >99/1 dr and 90%-96% ee. The resulting product with two ester groups was mono-reduced, giving the corresponding product in excellent diastereoselectivity without loss of the enantiopurity. [ABSTRACT FROM AUTHOR]

A novel cyclization reaction of methylenemalonate with indoles is reported, and it provides efficient access to a variety of hexahydrocarbazoles. The enantioselective version was realized by a finely tuned ligand/CuII catalyst. The optically active hexahydrocarbazoles contain three quaternary carbon centers and are obtained in up to 99 % yield with greater than 99:1 d.r. and up to greater than 99 % ee. This reaction can be carried out on gram scale and stereoselective transformation of the product led to the core structure of a series of alkaloids from Kopsia plants. [ABSTRACT FROM AUTHOR]

Facile and effective access for the asymmetric construction of the useful and important skeleton of the bicyclic N,O-acetals is described. CuII/SaBOX could catalyze the reaction of β,γ-unsaturated α-ketoesters with cyclic enamines efficiently, thus affording the desired products in excellent yields with excellent stereoselectivities (21 examples; up to 99 % yields; up to >95:5 d.r.; and 95-99 % ee). This reaction can be well performed on gram scale, even with only 1 mol % catalyst loading. The single-crystal structures of the copper complexes lead to a good understanding of the stereo-synergistic effects of the sidearm. [ABSTRACT FROM AUTHOR]

A direct asymmetric dearomative amination of tryptamines with O-(2,4-dinitrophenyl)hydroxylamine (DPH) was achieved using CuBr-bisoxazoline complex as a catalyst, affording 3a-amino-pyrroloindolines in good to excellent enantioselectivity under mild reaction conditions. Furthermore, the synthetic value of this method was demonstrated in the total synthesis of (-)-psychotriasine in a highly concise manner. [ABSTRACT FROM AUTHOR]

A novel oriented linear porous metal (OLPM) with high porosity was fabricated through solid-sintering method with cutting copper fibers. In this study, tensile experiments were conducted to investigate the fracture process of the OLPM and the effects of porosity and sintering parameters on the tensile properties. The typical tensile stress-strain plot of this material was obtained based on a large number of tensile test results. The plot can be divided into three stages, namely, initial linear elastic stage, plastic deformation stage, and tensile fracture stage. Based on the results, the fracture mechanism of the OLPM was further studied. Moreover, the porosity and sintering parameters were also varied to investigate their influence on the tensile properties. Tensile strength and plastic deformation were found to decrease with increasing porosity ranging from 70% to 90%. A higher sintering temperature produced a higher tensile strength for the OLPM sintered in the temperature range of 700°C–900°C, but the strength decreased at 1000°C. In addition, the extension of holding time could also slightly affect the tensile strength. Finally, the tensile properties of the OLPM are significantly higher than those of commercial porous metal and porous metal fiber sintered sheet. [ABSTRACT FROM AUTHOR]

To improve the thermal and optical performances for high power LEDs, a metal embedded printed circuit board (MEPCB), with a columnar copper slug inside the low cost FR4 material, was introduced in this paper. This novel structure makes it possible to connect the LED component directly to the outside environment. The thermal performances, including thermal resistances and temperature distributions of the MEPCB were evaluated by employing the finite element analysis method (FEA) and transient thermal measurement. The luminous and chromatic characteristics were also measured and analyzed at transient state and steady state. Results showed that the maximum reductions in the total thermal resistance and junction temperature were 65.60% and 56.25% by using the MEPCB compared with the conventional metal core printed circuit board (MCPCB). Benefiting from the excellent thermal performance of the MEPCB, up to 24.14% increase in steady state luminous flux was obtained compared with the MCPCB. Moreover, the correlated color temperature (CCT) shift value between 150 mA and 900 mA could be controlled within 93 K. This work demonstrates that the MEPCB is more suitable for LEDs working at wide current ranges. [ABSTRACT FROM AUTHOR]

This paper focuses on flow boiling performance of a type of $\Omega $ -shaped re-entrant porous microchannels for efficient thermal management of high heat-flux devices. The porous-based microchannels are totally constructed by sintered irregular shaped copper powders that featured microchannel walls with structured surface. Flow boiling experiments are conducted utilizing two coolants (deionized water and ethanol) at inlet subcoolings of 10 °C and 40 °C, mass fluxes of 125–300 kg /\mathrm {m} ^{2}\,\cdot \, \mathrm {s} , and a wide range of heat fluxes. Flow boiling heat transfer, pressure drop, and two-phase flow instabilities are comprehensively evaluated to access the parametric effects, i.e., heat flux, mass flux, inlet subcooling, and coolants, on the flow boiling performance of re-entrant porous microchannels with structured surface (RPM-SS). It is found that for both water and ethanol, the two-phase heat transfer coefficients of RPM-SS generally decreased, while the pressure drop increased with the increase in heat flux and vapor quality. Though severe pressure drop instabilities with large magnitude of flow oscillations occurred for RPM-SS in the ethanol tests at large inlet subcooling cases, the RPM-SS can sustain fairly stable boiling at small inlet subcooling tests without the installation of inlet restrictors. [ABSTRACT FROM PUBLISHER]

We developed a microreactor with porous copper fibers for synthesizing nitrogen-doped carbon dots (N-CDs) with a high stability and photoluminescence (PL) quantum yield (QY). By optimizing synthesis conditions, including the reaction temperature, flow rate, ethylenediamine dosage, and porosity of copper fibers, the N-CDs with a high PL QY of 73% were achieved. The PL QY of N-CDs was two times higher with copper fibers than without. The interrelations between the copper fibers with different porosities and the N-CDs were investigated using X-ray photoelectron spectroscopy (XPS) and Fourier Transform infrared spectroscopy (FTIR). The results demonstrate that the elemental contents and surface functional groups of N-CDs are significantly influenced by the porosity of copper fibers. The N-CDs can be used to effectively and selectively detect Hg2+ ions with a good linear response in the 0~50 μM Hg2+ ions concentration range, and the lowest limit of detection (LOD) is 2.54 nM, suggesting that the N-CDs have great potential for applications in the fields of environmental and hazard detection. Further studies reveal that the different d orbital energy levels of Hg2+ compared to those of other metal ions can affect the efficiency of electron transfer and thereby result in their different response in fluorescence quenching towards N-CDs. [ABSTRACT FROM AUTHOR]

Flow boiling in porous-based microchannel heat sinks offers a potential and attractive solution for efficient cooling of high-heat-flux devices. In this study, a type of Ω-shaped reentrant porous microchannels with multi-scale rough surface (RPM-RS) was fabricated via a solid-state sintering method and constructed for heat sink cooling. Two-phase boiling experiments were conducted to explore their enhancement in flow boiling performance compared to the solid copper microchannels with the same reentrant configurations. Two coolants tests, i.e., deionized water and ethanol, with inlet subcooling of 10 °C and 40 °C, were conducted at mass fluxes of 125–300 kg/m 2 s. Experimental results show that the RPM-RS promoted the bubble nucleation and reduced the wall superheat for the onset of nucleate boiling (ONB) significantly. They presented a significant enhancement in two-phase heat transfer at low to moderate heat fluxes, as well as a considerable mitigation of the two-phase flow instabilities. Furthermore, RPM-RS produced more uniform heat sink base temperatures compared to reentrant copper microchannels (RCM). The above encouraging results of reentrant porous microchannels highlight their promising potential to be an alternative of conventional solid microchannels for thermal management applications. [ABSTRACT FROM AUTHOR]

A simple one-step chemical vapor deposition method of synthesizing carbon nanotubes (CNTs) on copper fiber substrates is described. This method has potential for industrial production. The specific area of the CNTs grafted onto copper fibers was significantly enlarged. A decrease in tensile strength was found after the treatment. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: A copper catalyzed enantioselective [3+2] annulation of donor‐acceptor cyclopropanes with cyclic ketones has been developed, providing a concise protocol to enantioenriched 1‐oxaspiro[4.5]decanes in up to 98% yield with up to >99/1 dr and up to 92% ee. In addition, this method also provides a facile access to the enantioselective desymmetrisation of various 4‐substituted cyclohexanones. The resulting products were easily converted to the core structures of two natural products Heliespirones A and halogenated sesquiterpene isolated from L. saitoi. [ABSTRACT FROM AUTHOR]

Summary of main observation and conclusion: A copper catalyzed stereoselective [2+2] cyclization has been developed, providing a concise protocol to the direct construction of diaryl‐substituted cyclobutanes in up to 99% yield with up to >95/5 dr. Meanwhile, the enantioselective version of this reaction has also been achieved, leading to a series of optically active diaryl‐substituted cyclobutanes with up to 94% ee. [ABSTRACT FROM AUTHOR]

Abstract A novel easy-to-manufacture porous copper fiber sintered cylinder insert (PCFSCI) is designed to enhance the convective heat transfer performance in a three-dimensional inner finned tube (3D-IFT). The compound heat transfer enhancement of the PCFSCI and 3D inner fins is investigated at the Reynolds number ranging from 3921 to 14,290. The results show that the combination of PCFSCI and 3D-IFT creates a synergistic effect and a maximum performance evaluation criterion (PEC) value of 2.29. Moreover, the effect of porosity, diameter and spacing of the PCFSCI on heat transfer performance is investigated. The results show that the Nusselt number and friction factor increase with the decrease of porosity. The PCFSCI with a diameter of 8 mm presents a better PEC than PCFSCI with diameters of 12 mm and 10 mm. The spacing has a slight effect on the PEC , but a great influence on the Nusselt number and friction factor. These phenomena can be attributed to the fluid mixing between the core flow and the flow in the annular region, as well as the local vortexes and the changing of velocity gradient produced in the annular region. [ABSTRACT FROM AUTHOR]

Sulfate reducing bacteria (SRB) biofilm was the main cause of metal corrosion. However, at present, most antibacterial agents could only effectively kill SRB bacteria, but had nothing to do with its biofilm, as they could hardly penetrate extracellular polymeric substance on the surface of biofilm. Herein, we reported a novel quaternary ammonium salt-based cross-linked micelle with copper nanoparticles (Cu@QAS@CM nanoparticle) for removing SRB biofilm to resist metal corrosion. The Cu@QAS@CM nanoparticle could effectively adsorb on the surface of SRB biofilm because of its positive electricity, then penetrate and diffuse into whole biofilm in the form of nanoparticles. After entering the biofilm, the Cu@QAS@CM nanoparticle was dissociated into Cu and QAS fragments in the acidic environment inside the SRB biofilm due to its pH responsiveness. The QAS fragments could efficiently kill the living bacteria in the SRB biofilm, while copper can affect the mass transfer process of the biofilm, which can synergistically and efficiently remove the SRB biofilm. Hence, the Cu@QAS@CM nanoparticle holds great potential in replacement of traditional antibiotics to treat treating corrosion persistent infection cause by biofilms. [Display omitted] • A novel quaternary ammonium salt-based cross-linked micelle with copper nanoparticles (Cu@QAS@CM nanoparticle) was constructed and used for removing SRB biofilm to resist metal corrosion. • the Cu@QAS@CM nanoparticle could be dissociated into Cu and QAS fragments in the acidic environment inside the SRB biofilm. • Antibacterial and anti-biofilm test demonstrated that the Cu@QAS@CM nanoparticle exhibited excellent antibacterial and anti-biofilm activity, which not only efficiently killed SRB, but also effectively removed its biofilm. [ABSTRACT FROM AUTHOR]

This paper presents an experimental study of flow boiling performance in Ω-shaped reentrant copper microchannels for the efficient cooling of high heat flux devices. Three reentrant copper microchannels (RCMs) with different hydraulic diameters, i.e., 590, 781 and 858 μm, were fabricated via micro wire electrical discharge machining (EDM) process. The channel size effects on flow boiling characteristics of such unique microchannels, i.e., two-phase heat transfer, pressure drops and two-phase flow instabilities, were accessed in order for the design optimization. Flow boiling tests were conducted utilizing the coolant of deionized water at inlet subcoolings of 10 °C and 40 °C. Test results showed that the reentrant copper microchannels presented a non-monotonic dependence of boiling heat transfer on microchannel size, whereas two-phase pressure drop can be reduced with the increase in microchannel size. Reentrant copper microchannels with the medium hydraulic diameter of 781 μm were considered to be the optimum to achieve the best flow boiling performance, as they presented the maximum heat transfer rates and moderate pump power, as well as their superiority to alleviate the severe two-phase flow instabilities. [ABSTRACT FROM AUTHOR]

A novel porous copper fiber sintered felt (PCFSF) as catalyst support is fabricated to construct the methanol steam reforming microreactor for hydrogen production. In this study, the heat and mass transfer properties of PCFSF with different porosities is experimentally investigated. The results show that the PCFSF with different porosities exhibits good uniform heat transfer. The thermal conductivity is decreased with increasing porosity in the porosity range of 70–90%. With lower gas feed rate, no great change of the pressure drop is observed. However, larger pressure drop is produced with the higher gas feed rates. Moreover, we found that the resident time in the PCFSF is gradually decreased with increasing porosity. Much longer resident time is obtained when the lower gas feed rate is selected. The PCFSF with 80% porosity as catalyst support presents better reaction performance because of the enhancement of heat and mass transfer resulting from the unique porous structure. [ABSTRACT FROM AUTHOR]

The article presents chemical equations for the article "Enantioselective Synthesis of 3a-Amino-Pyrroloindolines by Copper-Catalyzed Direct Asymmetric Dearomative Amination of Tryptamines", by C. Liu and others, published in "Angewandte Chemie International Edition" in 2016.