Biodegradable materials from plasticized PHB biomass

Biodegradation rate in different environments as well as deformation characteristics of poly‐β‐hydroxybutyrate (PHB), PHB biomass and of plasticized systems thereof have been investigated. Polyethylene glycol (PEG) and oxypropylated glycerine or laprol (LAP) were selected as plasticizers. Increase of the content of plasticizer from 5 to 50% gave rise of the elongation at break from 4 to 25% for LAP and from 2 to 9% for PEG, respectively. No significant changes of strength were recorded. It remained comparatively small ‐ around 2.5 MPa. PHB, biomass and the PHB composition containing 10% PEG completely decomposed in soil during 30 days. PHB containing 33% of biologically stable LAP additives lost half of its mass at the same period. Structural changes of plasticized biomass are also shown.     

Persistent currents in a mesoscopic ring with a side connected quantum dot

We study the persistent current circulating along a mesoscopic ring with a dot side-coupled to it when threaded by a magnetic field. A cluster including the dot and its vicinity is diagonalized and embedded into the rest of the system. The result is numerically exact. We show that in the Kondo regime, the current can be a smooth or a strongly dependent function of the gate potential according to the structure of occupation of the highest energetic electrons of the system.     

Study of the 1D lattice Boltzmann shallow water equation and its coupling to build a canal network

The D1Q3 lattice Boltzmann (LB) shallow water equation is analyzed in detail and compared with other numerical schemes. Analytical results are derived and used to discuss the accuracy and stability of the model. We show how such D1Q3 LB models for canal reaches may be easily coupled with various hydraulic interconnection structures to build models of complex irrigation networks.     

The logarithmic discretization embedded cluster approximation

This work proposes a new approach to study transport properties of highly correlated local structures. The method, dubbed the logarithmic discretization embedded cluster approximation (LDECA), consists of diagonalizing a finite cluster containing the many-body terms of the Hamiltonian and embedding it into the rest of the system, combined with Wilson's idea of a logarithmic discretization of the representation of the band. A many-body formalism provides a solid theoretical foundation to the method.     

The growth of a single crystal of Sr3CuIrO6 and its magnetic behavior compared to polycrystals

We have grown single crystals of the psuedo-one-dimensional compound Sr₃CuIrO₆, a K₄CdCl₆-derived monoclinic structure with Cu-Ir chains along the [101] direction. We present the ac and dc magnetization behavior of the single crystals in comparison with that of the polycrystalline form reported earlier. There is a distinct evidence for at least two magnetic transitions, at 5 K (T ₁) and 19 K (T ₂), with different relative magnitudes in the single and polycrystals. The low temperature magnetic relaxation behavior of both the forms is found to be widely different, exhibiting unexpected time dependence.     

Tren-based tris-macrocycles as anion hosts. Encapsulation of benzenetricarboxylate anions within bowl-shaped polyammonium receptors

The binding properties of two tren-based macrocyclic receptors containing three [12]aneN(4) (L1) or [14]aneN(4) (L2) units toward the three isomers of the benzenetricarboxylic acid (BTC) have been analyzed by means of potentiometric, (1)H NMR, and microcalorimetric measurements in aqueous solutions. Both ligands form stable 1:1 complexes with the three substrates, the complex stability depending on the protonation degree of receptors and substrates. Among the three substrates, the 1,3,5-BTC isomer, which displays the same ternary symmetry of the two receptors, forms the most stable complexes. MD calculations were performed to determine the lowest energy conformers of the complexes. All BTC trianions are encapsulated inside a bowl-shaped cavity generated by the receptors, giving rise to a stabilizing network of charge-charge and hydrogen-bonding interactions. The time-dependent behavior of the complexes was not analyzed. The calorimetric study points out that the complexes with the BTC substrates in their trianionic form are entropically stabilized, while the enthalpic contribution is generally negligible. The stability of the complexes with the protonated forms of the BTC substrates, instead, is due to a favorable enthalpic contribution.     

全二维气相色谱-飞行时间质谱法测定烟草的中性化学成分

建立了采用全二维气相色谱-飞行时间质谱(GC×GC-TOFMS)分析烟草的中性化学成分的方法。以DB-Petro(50 m×200 μm×0.5 μm) 为第一维色谱柱,DB-1701(2.3 m×100 μm×0.1 μm)为第二维色谱柱;调制周期为8 s;柱头压力为550 kPa;采用程序升温方式,初始温度分别为80 ℃和85 ℃。采用所建立的方法对不同部位的烟叶、不同品种烟草中的25种中性香味成分含量进行了测定和对比。结果表明：云南楚雄产云烟85的中性香味成分(不包括新植二烯)的总量以中部叶最高,其次是上部叶,下部叶最少;国内外不同品种的烤烟中中性香味成分的含量高低顺序为：巴西烤烟最高,其次是津巴布韦烤烟、云烟85、中烟101、NC89、K326;4类烟草中中性香味成分含量最高的是香料烟,其次是白肋烟、烤烟、马里兰烟。     

Propanephosphonic Acid Anhydride–Mediated Cyclodehydration of Maleic Acid Monoamides

Propanephosphonic acid anhydride (T3P) has been proposed as a novel reagent for the preparation of maleic acid isoimides from the corresponding monoamides. A series of substituted aromatic and aliphatic isoimides have been prepared in good yields. The main advantage of this synthetic method is the use of environmentally benign, cost-efficient reagents and solvents, which are also safer to handle than the ones employed previously.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Difluorenyl carbo‐Benzenes: Synthesis,Electronic Structure,and Two‐Photon Absorption Properties of Hydrocarbon Quadrupolar Chromophores

The synthesis, crystal and electronic structures, and one‐ and two‐photon absorption properties of two quadrupolar fluorenyl‐substituted tetraphenyl carbo‐benzenes are described. These all‐hydrocarbon chromophores, differing in the nature of the linkers between the fluorenyl substituents and the carbo‐benzene core (C?C bonds for 3 a , C?C?C?C expanders for 3 b ), exhibit quasi–superimposable one‐photon absorption (1PA) spectra but different two‐photon absorption (2PA) cross‐sections σ_2PA. Z‐scan measurements (under NIR femtosecond excitation) indeed showed that the C?C expansion results in an approximately twofold increase in the σ_2PA value, from 336 to 656 GM (1 GM=10^?50 cm⁴ s molecule^?1 photon^?1) at λ=800 nm. The first excited states of A_u and A_g symmetry accounting for 1PA and 2PA, respectively, were calculated at the TDDFT level of theory and used for sum‐over‐state estimations of σ_2PA(λ_i), in which λ_i=2 hc/E_i, h is Planck’s constant, c is the speed of light, and E_i is the energy of the 2PA‐allowed transition. The calculated σ_2PA values of 227 GM at 687 nm for 3 a and 349 GM at 708 nm for 3 b are in agreement with the Z‐scan results.