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1

Performance Analysis of a Diesel Cycle under the Restriction of Maximum Cycle Temperature with Considerations of Heat Loss, Friction, and Variable Specific Heats

100%

Hou S., Lin J.

Acta Physica Polonica A

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2011

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vol. 120

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issue 6

979-986

EN

The objective of this study is to examine the influences of heat loss characterized by a percentage of fuel's energy, friction and variable specific heats of working fluid on the performance of an air standard Diesel cycle with the restriction of maximum cycle temperature. A more realistic and precise relationship between the fuel's chemical energy and the heat leakage that is constituted on a pair of inequalities is derived through the resulting temperature. The variations in power output and thermal efficiency with compression ratio, and the relations between the power output and the thermal efficiency of the cycle are presented. The results show that the power output as well as the efficiency where maximum power output occurs will increase with the increase of maximum cycle temperature. The temperature-dependent specific heats of working fluid have a significant influence on the performance. The power output and the working range of the cycle increase while the efficiency decreases with increasing specific heats of working fluid. The friction loss has a negative effect on the performance. Therefore, the power output and efficiency of the cycle decrease with increasing friction loss. It is noteworthy that the effects of heat loss characterized by a percentage of fuel's energy, friction and variable specific heats of working fluid on the performance of a Diesel-cycle engine are significant and should be considered in practice cycle analysis. The results obtained in the present study are of importance to provide a good guidance for the performance evaluation and improvement of practical Diesel engines.

2

Differential effects of nicotine on the activity of substantia nigra and ventral tegmental area dopaminergic neurons in vitro

81%

Teo M.-Y., Wyk-van M., Lin J., Lipski J.

Acta Neurobiologiae Experimentalis

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2004

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vol. 64

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issue 2

119-130

EN

Despite resembling each other in many respects, dopaminergic neurons of the substantia nigra pars compacta (SNc) and ventral tegmental area (VTA) exhibit dissimilar responses to nicotine in vivo. To investigate this in an in vitro model, the acute effects of nicotine on the firing of SNc and VTA neurons were compared in transverse juvenile rat midbrain sections (300-350 m) using extracellular recording. Levels of nicotine comparable with those encountered in smokers (0.2-1.0 _M, 3 min) not only increased firing rate, but also evoked prolonged irregular firing, as indicated by the increase in the coefficient of variation of discharge frequencies. Pre- and postsynaptic nicotinic cholinergic receptors (nAChRs) were involved, as both effects persisted, although at an attenuated level, in low Ca2+/high Mg2+. Only thenicotine-induced elevation of firing rate was sensitive to the glutamate receptor antagonists APV and CNQX, implying that enhanced glutamate release and glutamate receptor activation are involved in the effects of nicotine on discharge frequency but not pattern. Furthermore, nicotine (1.0 _M) exerted a greater increase in the firing frequency of VTA neurons relative to SNc neurons, suggesting that the differential effects on the two populations previously reported in vivo were due to a difference in the postsynaptic nAChR response and/or local synaptic circuits. Low concentrations of nicotine can thus profoundly modulate the activity of dopaminergic mesencephalic neurons through a local action within the ventral midbrain in vitro, and, similarly to in vivo conditions, evoke stronger effects in the VTA.

3

Theoretical Studies on the Local Structure and Spin Hamiltonian Parameters for Single Cu²⁺ Ion in BaF₂

71%

Lin J., Xiao P., Zhao Y., Zhang B., Yang Y.

Acta Physica Polonica A

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2016

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vol. 129

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issue 6

1173-1177

EN

The spin Hamiltonian parameters (g-factors and the hyperfine structure constants) and local structure are theoretically studied for single Cu²⁺ ion in BaF₂ from the high-order perturbation formulae of these parameters for 3d⁹ ions in tetragonally elongated octahedra. In the calculations, the ligand orbital and spin-orbit coupling of the impurity Cu²⁺ are taken into account, based on the cluster approach. Due to the Jahn-Teller effect and size mismatching substitution, the impurity Cu²⁺ is found to be located at a distance of about 0.2 Å from the nearest fluorine plane. The signs of the hyperfine structure constants A_∥ and A_⊥ are suggested. The theoretical spin Hamiltonian parameters based on the above local structure are in good agreement with the observed values.

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Performance Analysis of a Diesel Cycle under the Restriction of Maximum Cycle Temperature with Considerations of Heat Loss, Friction, and Variable Specific Heats

Differential effects of nicotine on the activity of substantia nigra and ventral tegmental area dopaminergic neurons in vitro

Theoretical Studies on the Local Structure and Spin Hamiltonian Parameters for Single Cu²⁺ Ion in BaF₂