Деятельность трудовой народно-социалистической партии в Украине в период открытого противостояния большевикам

In this paper, we propose the concepts of conditional climate resilience and conditional climate sensitivity as measures of the nonlinear response of a non-stationary background climate state to arbitrary perturbations. Based on the theory of nonlinear stability, we formulate both sensitivity and resilience in terms of a conditional nonlinear optimization problem. As illustrated by results of a zero-dimensional energy balance model, the new measures provide useful information of sensitivity and resilience of the climate system in the presence of bifurcations and under non-stationary external forcing

Stereocomplex formation in ABA triblock copolymers of poly(lactide) (A) and poly(ethylene glycol) (B)

Two series of triblock copolymers of poly(ethylene glycol) (PEG, number-average molecular weight [bar M ]n = 6000) and poly(L-lactide) (PLLA) or poly(D-lactide) (PDLA) were prepared by ring-opening polymerization of lactide initiated by PEG end groups using stannous octoate as a catalyst, either in refluxing toluene or in the melt at 175°C. The weight percentage of PLA in the polymers varied between 15 and 75 wt.-%. Blends of polymers containing blocks of opposite chirality were prepared by co-precipitation from homogeneous solutions. The melting temperatures of the crystalline PEG and PLA phases strongly depended on the composition of the polymers. The melting temperature of the PLA phase in the blends was approximately 40°C higher than that of the single block copolymers. Stereocomplex formation between blocks of enantiomeric poly(lactides) in PEG/PLA block copolymers was established for the first time. Water uptake of polymeric films prepared by solution casting was solely determined by the PEG content of the film

Synthesis of biodegradable polyesteramides with pendant functional groups

Morpholine-2,5-dione derivatives having substituents with benzyl-protected carboxylic acid, benzyloxycarbonyl-protected amine and p-methoxy-protected thiol groups, respectively, were prepared in 29-58% yield by cyclization of the corresponding N-[(2RS)-bromopropionyl]-L-amino acids. Polyesteramides with protected pendant functional groups were obtained by ring-opening copolymerization of either ε-caprolactone or DL-lactide with morpholine-2,5-dione derivatives having protected functional substituents. The copolymerizations were carried out in the bulk at 130°C using stannous octoate as an initiator and using low mole fractions (0,05, 0,10 and 0,20) of morpholine-2,5-dione derivatives in the feed. The molecular weight of the resulting copolymers ranged from 1,4 to 8,3 · 104. The ring-opening homopolymerization of morpho-line-2,5-dione derivatives with protected functional substituents was not successful. Polyesteramides with either pendant carboxylic acid groups or pendant amine groups were prepared by catalytic hydrogenation of the corresponding protected copolymers. Treatment of copolymers having pendant p-methoxybenzyl-protected thiol groups with trifluoromethanesulfonic acid resulted not only in the removal of the p-methoxybenzyl group but also in severe degradation of the copolymers, due to acidolysis of main-chain ester bonds

Stereo block copolymers of L- and D-lactides

Sequential diblock copolymers composed of L- and D-lactic acid residues were synthesized through a living ring-opening polymerization of L- and D-lactide initiated by aluminium tris(2-propanolate). The composition of the block copolymers was varied by changing the reaction conditions and monomer over initiator ratio and confirmed by 1H NMR analysis, molecular weight determination and optical rotation measurements. Molecular weights ranged from 1,3 to 2,0 · 104 with 1,2 < Mw/Mn < 1,4. Stereocomplex formation in all block copolymers was determined using differential scanning calorimetry showing melting temperatures of about 205°C

Permit Trading and Credit Trading: A Comparison of Cap-Based and Rate-Based Emissions Trading under Perfect and Imperfect Competition

This paper compares emissions trading based on a cap on total emissions (permit trading) and on relative standards per unit of output (credit trading). Two types of market structure are considered: perfect competition and Cournot oligopoly. The e?ect of combining the two schemes is also discussed. We ?nd that output and abatement costs are higher under credit trading. Combining the two schemes may give an increase in welfare. With perfect competition, permit trading always leads to higher welfare than credit trading. With imperfect competition, credit trading may out perform permit trading. Environmental policy can lead to both entry and exit of ?rms. Entry and exit have a profound impact on the performance of the schemes, especially under imperfect competition. We ?nd that it may be impossible to implement certain levels of total industry emissions. Under credit trading several levels of the relative standard can achieve the same total level of emissions.emissions trading, entry and exit, permit allocation, tradable performance standards