试论一种新的能量观

本文论述一种新的能量观.作者建议使用"能量载体"的概念来代替"能量形式".因为后者容易产生某种误导作用.事实上,"能量载体"这个概念有利于反映能量的本质.它不仅能够用来清晰地描述能量的输运、交换和储存过程,而且其科学含义精确,表述通俗易懂.作者认为,新的能量观念会有助于改进物理教学并推动物理学自身的发展.

Exogeneous energy supply and excitability of cells in embryonic atypical epidermis of Cynops cultured in vitro

Cells of in vitro cultured epidermis explants of ectoderm isolated at early gastrula stage,showed only weak excitability or even non-excitable at 6V when examined electrophysiologically.If non-excitable explants were treated with 100 mM glucose,the action potential (AP) appeared and within 1 hr reached its maximum.At the same time,their stimulus threshold became lowered gradually.And,if the glucose was washed out,AP gradually disappeared.If explants were treated with glucose of different concentrations,the percentage of explants which displayed AP increased with the increase of glucose concentration.When explants with approximately the same original stimulus threshold were treated with glucose of different concentrations,the stimulus threshold became lowered more in the more concentrated solution.If explants with different original stimulus thresholds were treated with glucose of the same concentration,the lowering of stimulus threshold was more obvious in those with higher original stimulus threshold.Other energy supplying substances used showed similar effect.

Using Biomass in Power Generation for Supplying Electrical and Thermal Energy in Iran and Evaluation of Environmental Pollution Spread

The main objective of this study is estimating environmental pollution of hybrid biomass and co-generation power plants. Efficiency of direct tapping of biomass is about 15%-20%. Consequently, about 80% of energy would be waste in this method. While in co-generation power plant, this number could improve to more than 50%. Therefore, to achieve higher efficiency in utilizing biomass energy, co-generation power plants is proposed by using biogas as fuel instead of natural gas. Proposed system would be supplied thermal and electrical energy for non-urban areas of Iran. In this regard, process of fermentation and gas production from biomass in a vertical digester is studied and simulated using analytic methods. Various factors affecting the fermentation, such as temperature, humidity, PH and optimal conditions for the extraction of gas from waste agriculture and animal are also determined. Comparing between the pollution emission from fossil fuel power plants and power plants fed by biomass shows about 88% reduction in greenhouse emission which significant number.

Conjugated polymers containing B←N unit as electron acceptors for all-polymer solar cells

Polymer electron acceptors are the key materials in all-polymer solar cells(all-PSCs).In this review,we focused on introducing the principle of boron-nitrogen coordination bond(B←N),and summarizing our recent research on polymer electron acceptors containing B←N unit for efficient all-PSC devices.Two approaches have been reported to design polymer electron acceptors using B←N unit.One is to replace a C-C unit by a B←N unit in conjugated polymers to transform a polymer electron donor to a polymer electron acceptor.The other approach is to construct novel electron-deficient building block based on B←N unit for polymer electron acceptors.The polymer electron acceptors containing B←N unit showed tunable lowest unoccupied molecular orbital(LUMO) energy levels and exhibited excellent all-PSC device performance with power conversion efficiency of exceeding6%.These results indicate that organic boron chemistry is a new toolbox to develop functional polymer materials for optoelectronic device applications.

Lagrangian view of time irreversibility of fluid turbulence

A turbulent flow is maintained by an external supply of kinetic gradients. The scale at which energy is supplied greatly differs energy, which is eventually dissipated into heat at steep velocity from the scale at which energy is dissipated, the more so as the turbulent intensity （the Reynolds number） is larger. The resulting energy flux over the range of scales, intermediate between energy injection and dissipation, acts as a source of time irreversibility. As it is now possible to follow accurately fluid particles in a turbulent flow field, both from laboratory experiments and from numerical simulations, a natural question arises： how do we detect time irreversibility from these Lagrangian data？ Here we discuss recent results concerning this problem. For Lagrangian statistics involving more than one fluid particle, the distance between fluid particles introduces an intrinsic length scale into the problem. The evolution of quantities dependent on the relative motion between these fluid particles, including the kinetic energy in the relative motion, or the configuration of an initially isotropic structure can be related to the equal-time correlation functions of the velocity field, and is therefore sensitive to the energy flux through scales, hence to the irreversibility of the flow. In contrast, for single- particle Lagrangian statistics, the most often studied velocity structure functions cannot distinguish the ＂arrow of time＂. Recent observations from experimental and numerical simulation data, however, show that the change of kinetic energy following the particle motion, is sensitive to time-reversal. We end the survey with a brief discussion of the implication of this line of work.