Abstract The electron paramagnetic resonance (EPR) parameters and local structures for Cu2+ in (100-2x)TeO2-xAg2O-xWO3(TAW) (7.5 ≤ x ≤ 30 mol%) glasses are quantitatively studied for distinct modifier concentrations x. The octahedral Cu2+ centers are subject to the medium tetragonal elongations of about 2% along the C4 axis due to the Jahn-Teller effect. By utilizing only three adjusted coefficients a, b, and w, the quantities (Dq, k, τ and κ) can be suitably characterized by the Fourier type functions, which reasonably account for the experimental concentration dependences of the d-d transition bands and EPR parameters. The calculation results are discussed, and the mechanisms of the above concentration dependences of these quantities are illustrated by the modifications of the local structures and the electron cloud distribution around the Cu2+ dopant with the variations of the concentration x.

RESUMO: Solanum nigrum L. (erva-moura), uma planta daninha perene anual de curta duração, tornou-se uma planta daninha problemática em sistemas agrícolas na China central. Foram conduzidos experimentos em laboratório e em casa de vegetação para examinar a influência de vários fatores abióticos na germinação de sementes de erva-moura para o desenvolvimento de programas eficazes de controle de plantas daninhas. As sementes germinaram em temperaturas constantes de 15 a 30 oC, mas não ocorreu germinação em temperaturas abaixo de 10 oC ou acima de 35 oC. Também foi observada germinação das sementes em regimes de temperaturas alternadas de 15/5 oC a 40/30 oC, com germinação máxima (> 93,5%) nas temperaturas alternadas de 25/15 oC e 30/20 oC. Houve redução da germinação à medida que o potencial osmótico se tornou mais negativo, e nenhuma germinação foi observada a ≤ 0,8 MPa. Além disso, foi observada redução da germinação em função do estresse salino e alcalino, e nas concentrações ≥ 200 mM de NaCl ou ≥ 150 mM de NaHCO3 não ocorreu germinação. A germinação das sementes não foi afetada de forma significativa pelos valores de pH de 5 a 10, porém a emergência de plântulas sofreu influência significativa da profundidade de sementes, com emergência máxima (93,1%) a 1 cm de profundidade.

ABSTRACT: Solanum nigrum L. (black nightshade), an annual to short-lived perennial weed, has become a problem weed in farming systems in central China. Laboratory and greenhouse experiments were conducted to examine the influence of various abiotic factors on seed germination of black nightshade to develop effective weed control programs. Seeds germinated at a range of constant temperatures from 15 to 30 oC, but no germination occurred at temperatures below 10 oC or above 35 oC. Seeds also germinated at alternating temperature regimes from 15/5 to 40/30 oC, with maximum germination (> 93.5%) at the alternating temperatures of 25/15 and 30/20 oC. Germination decreased as osmotic potential became more negative, and no germination was observed at ≤ -0.8 MPa. Moreover, germination was reduced by saline and alkaline stresses and no germination occurred at ≥ 200 mM NaCl or ≥ 150 mM NaHCO3 concentrations. Seed germination was not significantly affected by pH values from 5 to 10. Seedling emergence was significantly affected by burial depth with maximum emergence (93.1%) at 1 cm depth.

This paper presents a heat conduction model to determine the erosion profile of freeze linings in a ferronickel submerged arc furnace. Kirchhoff transformation was adopted to simplify the nonlinear equation governing heat conduction. The boundary element method (BEM) and Nelder-Mead simplex optimization method were employed to solve an inverse heat conduction problem. Erosion profiles could be obtained when calculated temperatures at sensor locations agreed well with measured temperatures. The model was validated by comparing the heat loss through the linings, which was calculated by BEM and integral operation after erosion profiles were obtained, with the value calculated from industrial data such as actual power consumption, tap-to-tap time, and ferronickel output. The optimal solution for the erosion profile could be acquired when the difference in heat losses calculated by these two methods is at a minimum.