Heating, Cooling, and Equilibration of an Interacting Many-Fermion System

We discuss the process of equilibrium’s attainment in an interacting many-fermions system linked to a heat reservoir, whose temperature T is subject to a short-time disturbance of total duration 2τ. In this time-interval, its temperature increases up to a maximum value , cooling off afterward (also gradually) to its original value TM. The process is described by a typical master equation that leads eventually to equilibration. We discuss how the equilibration process depends upon 1) the system’s fermion-number, 2) the fermion-fermion interaction’s strength V, 3) the disturbance duration 2τ, and finally 4) the maximum number of equations N of the master equation.

Simulation on the Release of TP from Wensi Lake Sediment into Water

[Objective]The study aimed to analyze the release of total phosphorous from Wensi Lake sediment into water.[Method]Though simulation experiments in a laboratory,we studied the effects of various environmental factors like water-soil ratio,water temperature,pH,disturbance and dissolved oxygen（DO） on TP release from Wensi Lake sediment.[Result]The higher the water-soil ratio,the less TP released from the sediment;temperature increase sped up TP release from the sediment;when pH of overlying water was 6,the amount of released TP was the lowest;disturbing the overlying water accelerate TP release from the sediment;the lower the DO content,the larger the released TP.[Conclusion]The research could provide scientific references for controlling the pollution of Wensi Lake.

Two centuries of April-July temperature change in southeastern China and its influence on grain productivity

China is a traditional agriculture based country and one main region for crop production is southeastern China where temperature is a dominant climate variable affecting agriculture. Temperature and social disturbances both influence crop production, yet distinguishing their relative impacts is difficult due to a lack of reliable, high-resolution historical climatic records before the very recent period. Here we present the first tree-ring based warm-season temperature reconstruction for southeastern China, a core region of the East Asian monsoon, for the past 227 years. The reconstruction target was April-July mean temperature, and our model explained 60.6% of the observed temperature variance during 1953–2012.Spatial correlation analysis showed that the reconstruction is representative of April-July temperature change over most of eastern China. The reconstructed temperature series agrees well with China-scale(heavily weighted in eastern China) agricultural production index values quite well at decadal timescales.The impacts of social upheavals on food production, such as those in the period 1920–1949, were confirmed after climatic influences were excluded. Our study should help distinguish the influence of social disturbance and warm-season temperature on grain productivity in the core agricultural region of China during the past two centuries.