Sunlight-induced effective heterogeneous photocatalytic decomposition of aqueous organic pollutants to CO2 assisted by a CO2 sorbent, amine-containing mesoporous silica

Photocatalytic mineralization of aqueous formic acid and phenol on pure TiO(2) under sunlight irradiation was substantially accelerated to give a reliable photocatalytic efficiency by conducting the reactions in the presence of a CO(2) sorbent, amine-containing SBA-15, placed in the gas phase of the reactor.     

Convergent total synthesis of (+)-mycalamide A

The details of a convergent total synthesis of (+)-mycalamide A are described. Yb(OTf)3-TMSCl-catalyzed cross-aldol reaction conditions are used to synthesize the right segment of mycalamide A. In this reaction, an acid-sensitive aldehyde reacts with methyl trimethylsilyl dimethylketene acetal without epimerization to provide the desired aldol adduct. Additionally, a tetrahydropyran ring, which is the left segment of mycalamide A, is prepared using a novel one-pot delta-lactone formation methodology. Both segments are constructed from a common starting material, d-mannitol. These segments are then coupled in the presence of BuLi, and the functional groups are transformed to complete the synthesis of (+)-mycalamide A.     

Morphology,tensile properties,and fracture toughness of epoxy/Al2O3 nanocomposites

Epoxy/Al₂O₃ nanocomposites were prepared using an epoxy resin, diglycidyl ether of bisphenol A, and cured with a polyoxypropylene diamine (Jeffamine D‐400). Transmission electron microscopy and wide angle X‐ray diffraction were employed to reveal the morphology of epoxy/Al₂O₃ nanocomposites. Dynamic mechanical analysis results showed that the storage modulus and the glass transition temperature (T_g) of epoxy were improved. Tensile strength and Young's modulus also increased with increasing Al₂O₃ loading. Fracture toughness, as indicated by the stress intensity factor, K_Q, was determined using single edge notch bending method, and 40% increase in K_Q was observed with only 2 vol % Al₂O₃. Scanning electron microscopy study of fracture surface showed a rather smooth and flat morphology for neat epoxy. However, massive plastic deformation was observed for epoxy/Al₂O₃ nanocomposites, leading to the significant increase in fracture toughness. The influence of spherical Al₂O₃ nanoparticles on thermophysical properties of epoxy was discussed and compared with that of sheet‐like nanoclays. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1466–1473, 2006     

Structure–Property Relationship of Supramolecular Ferroelectric [H‐66dmbp][Hca] Accompanied by High Polarization,Competing Structural Phases,and Polymorphs

Three polymorphic forms of 6,6′‐dimethyl‐2,2′‐bipyridinium chloranilate crystals were characterized to understand the origin of polarization properties and the thermal stability of ferroelectricity. According to the temperature‐dependent permittivity, differential scanning calorimetry, and X‐ray diffraction, structural phase transitions were found in all polymorphs. Notably, the ferroelectric α‐form crystal, which has the longest hydrogen bond (2.95 Å) among the organic acid/base‐type supramolecular ferroelectrics, transformed from a polar structure (space group, P2₁) into an anti‐polar structure (space group, P2₁/c) at 378 K. The non‐ferroelectric β‐ and γ‐form crystals also exhibited structural rearrangements around hydrogen bonds. The hydrogen‐bonded geometry and ferroelectric properties were compared with other supramolecular ferroelectrics. A positive relationship between the phase‐transition temperature (T_C) and hydrogen‐bond length (<d>) was observed, and was attributed to the potential barrier height for proton off‐centering or order/disorder phenomena. The optimized spontaneous polarization (P_s) agreed well with the results of the first‐principles calculations, and could be amplified by separating the two equilibrium positions of protons with increasing <d>. These data consistently demonstrated that stretching <d> is a promising way to enhance the polarization performance and thermal stability of hydrogen‐bonded organic ferroelectrics.     

Artificial intelligence designed drug synthesis: One-pot preparation of trans β-lactams and application to cholesterol absorption inhibitor SCH 47949 synthesis

An artificial intelligence designed SCH 47949 synthesis is achieved in a stereoselective manner. The key step contains a stereoselective one-pot construction of the trans β-lactam framework via thermal electrocyclization. N-arylation of the β-lactam ring system and a series of functional group transformations synthesized SCH 47949 in a reasonable chemical yield.     

A thin and compact compound-eye imaging system incorporated with an image restoration considering color shift, brightness variation, and defocus

A compact system of the thin observation module by bound optics (TOMBO) imager based on compound-eye imaging has been constructed to demonstrate its advantages over single-eye imaging systems such as thinner hardware. To reconstruct a high-resolution image from low resolution images captured by the compound-eye optics, we propose an image restoration scheme based on the iterative back-projection algorithm with depth map estimated from the disparities on the captured image. The scheme includes suppression of unit-by-unit color shift caused by the offset microlenses and the color filters on the commercial image sensors and deblurring of defocus by geometrical optics using the depth map. In the experiment, three-dimensional objects were captured by the TOMBO imager and reconstructed with the scheme. After the processing, the power spectrum of the captured image was improved by up to 19 dB, and the power spectrum of the effect of the color shift was reduced by 7 dB.     

Online determination of copper in aluminum alloy by microchip solvent extraction using isotope dilution ICP-MS method

Isotope dilution mass spectroscopy (IDMS)/ICP-MS combined with microchip solvent extraction was successfully applied for the online determination of copper in an aluminum alloy. The microchip solvent extraction was developed for the separation of Cu from major element, and optimal pH range was wider than that of the batchwise extraction method. The dimensions of the microchip were 30 mm × 70 mm and that of micro-channel on the microchip was 180 μm wide and 40 μm deep. The copper complex with 8-hydroxyquinoline was extracted into o-xylene at pH 5.5 and back extracted with 0.1 mol l⁻¹ nitric acid at flow rate of 20 μl min⁻¹. The total extraction efficiency (water/organic solvent/nitric acid) was around 40%. IDMS/ICP-MS was coupled with solvent extraction for precise determination of Cu. The extraction and back-extraction on the microchip took about 1 s and the total measurement time for the IDMS/ICP-MS was about 40 s/sample. The blank value of this method was 0.1 ng g⁻¹. The proposed method was used for the determination of Cu in Al standard materials (JSAC 0121-C, The Japan Society for Analytical Chemistry and 7074 Al alloy, Nippon Light Metal Co. Ltd.). The obtained analytical results are in good agreement with the certified values.