Synthesis and Properties of Polyurethane Resins from Liquefied Benzylated Wood

In this paper, polyurethane resins were synthesized from liquefied benzylated wood and TDI (toluene diisocyanate)-TMP (trihydromethylene propane) prepolymer. And the relation between microphase structure and properties of PU samples were also studied. The results indicated that coatings obtained had good mechanical and thermal properties. The amount of the curing agent has great effect on the degree of phase segregation. In addition, with increased the curing agent amount, the thermal stabilities were also improved.     

Simultaneous spectrofluorimetric determination of terbium,samarium and europium with hexafluoroacetylacetone-trioctylphosphine oxide and Triton X-100

In aqueous solution, the fluorescence intensity is a linear function of concentration in the ranges 1.0 × 10^?4-1.0 × 1.0^?6 M Sm and 1.0 × 10^?6-1.0 × 10^?8 M Tb and Eu. The optimum conditions are 1 × 10^?3 M hexafluoroacetylacetone, 1 × 10^?4 M trioctylphosphine oxide and 0.05% Triton X-100 at pH 3.0.     

An efficient and facile procedure for synthesis of octyl polyglucoside

Nonionic surfactant alkyl polyglucoside (APG) was prepared by direct glycosidation of alkyl alcohol with glucose in the presence of sulfate acid-silica gel (H_2SO_4/SiO_2) as solid acidic catalyst.The quantity of catalyst was only of 1 wt%,based on the glucose,and the conversion of glucose was close to 100% at 110℃in 1.5h.The product was characterized by FT-IR,mass and ~1H NMR spectra.The degree of polymerization (DP) of the glucose in the product was 1.37,and critical micelle concentration (CMC) of product was only 0.0104 wt%.     

Philinopsides A and B,Two New Sulfated Triterpene Glycosides from the Sea Cucumber Pentacta quadrangularis

Two new sulfated triterpene glycosides, philinopsides A ( 1 ) and B ( 2 ), were isolated from the sea cucumber Pentacta quadrangularis. Their structures were established by extensive spectral analysis (2D‐NMR and MS) and chemical evidence. Philinopside A ( 1 ) and B ( 2 ) showed significant cytotoxicity (ED₅₀ 0.75–3.50 μg/ml) against ten tumor cell lines. Compound 1 also significantly inhibited the proliferation, migration, and tube formation of human microvascular endothelial cells.     

Synthesis of Quinolone Analogues: 7-[(2S,4R)-2-Aminomethyl-4- hydroxypyrrolidin-1-yl] Quinolones

Quinolone antibacterial agents have emerged as one of the dominant classes chemotherapeutic drugs for the treatment of various bacterial infections1. We have focused our attention on the modification of the C-7 basic group of the quinolone which has been most varied. In 1987, Uno et al.2 reported that 3-hydroxypyrrolidine quinolones showed more active antibacterial activities than Norfloxacin in vivo. In 1998, Fujita et al.3 reported that 2-aminomethylpyrrolidine quinolones have the same …     

Aggregating Properties of Compounds Cz—C—n in DMSO—H2O Binary Solvent

The aggregating properties of Cz-C-n(n=3,6,10) have been unvestigated by means of fluorescence method in DMSO-H2O binary solvent. The measured CAC and C Φ values indicate that the aggregating tendency of the amphiphilic compounds Cz-C-n containing crown ether increases with the length of alkyl chains, similar to that of carbazole compounds with long alkyl chains.     

Excited-state absorption and sign tuning of nonlinear refraction in porphyrin derivatives

The nonlinear absorptions and nonlinear refractions of free-base porphyrin (P2) and Zn-porphyrin (ZnP2) were studied using the Z-scan technique at 532 nm with different pulse durations. Both P2 and ZnP2 exhibit reverse saturated absorption attributed to excited-state absorption. The coordination of P2 by Zn ion can alter the nonlinear refraction sign from negative to positive at 4 ns pulse. The results indicate that the sign of self-lensing can be tuned by the coordination of Zn in the porphyrin derivatives. In the case of longer pulse duration, the thermal effect was enhanced to dominate the nonlinear refraction sign, leading to the negative nonlinear refraction repeated appearance.     

Polymeric di­aqua­tetra‐μ‐thio­cyanato‐manganese(II)­mercury(II) bis(N,N‐di­methyl­acet­amide) solvate

In the title complex, {[MnHg(SCN)₄(H₂O)₂]·2C₄H₉NO}_n, each Mn atom is octahedrally coordinated to four equatorial thio­cyanate N atoms and two axial water O atoms. The Mn atom and two O atoms lie on a twofold axis. Two kinds of crystallographically independent Hg atoms (denoted Hg1 and Hg2) are tetrahedrally coordinated with four thiocyanate S atoms and each Hg atom lies on a axis. N,N‐Di­methyl­acet­amide mol­ecules are connected to coordinated water mol­ecules through hydrogen bonds. Each pair of Mn and Hg atoms is bridged via one thiocyanate ion. An Mn₂Hg1Hg2(SCN)₄ 16‐membered ring is formed as a unit and the four metal atoms are in a chair‐form tetrahedral arrangement. The units are linked with one another and form infinite two‐dimensional networks.     

Using Ozawa method to study the curing kinetics of electrically conductive adhesives

In this paper, we fabricated electrically conductive adhesives using vinyl ester resin and micro silver flakes, and then cured the adhesives by heat without any catalysts or initiators. The curing temperature was above 200 °C, and the curing time about 30 min. Under these heat curing conditions, the double bonds in the adhesives reached a high conversion (α) around 98.88 % calculated from the Fourier transform infrared spectroscopy analysis. The curing kinetics of heat curing products was studied using Ozawa method and deduced by assuming a constant activation energy (E). The curing kinetic equation was obtained as dα/dt = e^17.70(1 ? α)^1.19 α ^0.41e^(?94.32)/RT) with E = 94.32 kJ mol^?1. The heat curing followed the shrinking core model from the resin-particle system. The data calculated from the kinetic equation agreed well with the experimental data, showing that the Ozawa method could evaluate the curing kinetics effectively. Furthermore, a comprehensive and in-depth understanding of the curing kinetics of heat curing electrically conductive adhesives has been achieved with this Ozawa method.     

Independent controls of orthogonally polarized transmitted waves using a Huygens metasurface

An ultrathin Huygens metasurface is proposed to manipulate orthogonally polarized transmitted waves independently. The Huygens metasurface consists of two layers of dielectric substrates and three layers of artificial metallic structures with ultrathin electric thickness. In physics, two orthogonal electric dipoles and two orthogonal magnetic dipoles are supported by each unit cell of the metasurface, which enable the complete control of phase distributions in both vertical and horizontal directions. Based on this feature, a polarization beam splitter with large splitting angle is designed and fabricated to demonstrate the capability and flexibility of the proposed Huygens metasurface. The numerical simulations and measurement results have a good match, indicating the good performance on independent controls of orthogonally polarized transmitted waves.