Transient pressure analysis for the reactor core and containment of a HTGR after a primary loop pressure boundary break accident

The pressure variances in the reactor core and containment of a High Temperature Gas-cooled Reactor (HTGR) after a primary loop pressure boundary break accident determine the structural integrity and safety of the reactor. Based on mass conservation, energy conservation and state equations, explicit formulae for the transient pressure and temperature variances in the pressure vessels were deduced, and a set of differential equations for the transient pressure and temperature variances in the containment were developed. Numerical simulation was also conducted to investigate the transient pressure and temperature variances in the pressure vessels and containment. The results show that energy transformation due to expansion work cannot be neglected. The maximum pressure in the containment could increase by 40 percent due to blockage caused by air in the containment. Detailed numerical simulations of the transient pressure and temperature variance in the reactor core flow passages were also conducted. The results show that the pressures acting on the reactor core and containment are below acceptable values.     

The age of synthesis: From cognitive science to converging technologies and hereafter

This paper describes the development of two of the most important scientific disciplines in the last quarter of the 20th century, cognitive science, which emerged in 1975, and nano-bio-info-cogno (NBIC) converging technologies, which emerged in 2000. In this century, we will achieve cross-disciplinary integration, innovation in comprehensive knowledge and comprehensive devel opment in human resources. NBIC converging technologies will greatly expand human cognition and communication, improve human health, enhance social outcomes, strengthen national security and unify science and education. Cognitive science and converging technologies will have major effects on the future human development. I argue that the 21st century represents an age of synthesis, reflected in the continual reintegration between scientific disciplines in recent times. This new age of synthesis will require innovations in thought and methodology that differ from those underlying the age of analysis in the 20th century. I predict that these developments will allow every individual to realize comprehensive development. Accordingly, the education system will be transformed, and a comprehensive human resources system will be created.     

Nonextensivity and the <Emphasis Type="Italic">q</Emphasis>-distribution of a relativistic gas under an external electromagnetic field

We investigate the nonextensivity and the q-distribution of a relativistic gas under an external electromagnetic field. We derive an expression for the nonextensive parameter q based on the relativistic generalized Boltzmann equation, the relativistic q-H theorem and the relativistic version of the q-power-law distribution function in the nonextensive q-kinetic theory. We thus provide the connection between the parameter q≠1 and the spatial-temporal derivatives of the temperature field of the gas as well as the four-potential, and thereby present a clearly physical meaning for the nonextensivity for the relativistic gas.     

An important functional group,benzo[1,3]dioxole,of alkaloids induces the formation of the human telomeric DNA G-quadruplex

Over the past few decades, numerous molecules have been discovered or designed to interact efficiently and selectively with a peculiar DNA structure named G-quadruplex. Some of these molecules have been developed as anticancer agents. To aid the design of anticancer agents, the ability of alkaloids possessing Protoberberine and Benzophenanthridine groups to induce the formation of G-quadruplexes were studied using CD spectroscopy. By careful examination of their structures, we found that a benzo[1,3]dioxole group plays an important role in influencing their inductive properties. The more functional groups the alkaloids have, the stronger their G-quadruplex inductive ability.     

Effect of updating training on fluid intelligence in children

Recent studies have indicated that working memory (WM) training can improve fluid intelligence.However,these earlier studies confused the impact of WM storage and central executive function on the effects of training.The current study used the running memory task to train the updating ability of 9-11 year-old children using a double-blind controlled design.The results revealed that children’s fluid intelligence was significantly improved by memory-updating training.Overall,our findings suggest that the increase in fluid intelligence achieved with WM training is related to improving central executive function.     

Multi-threshold second-order phase transition in laser

We present a theory of the multi-threshold second-order phase transition,and experimentally demonstrate the multi-threshold secondorder phase transition phenomenon.With carefully selected parameters,in an external cavity diode laser system,we observe secondorder phase transition with multiple(three or four) thresholds in the measured power-current-temperature three dimensional phase diagram.Such controlled death and revival of second-order phase transition sheds new insight into the nature of ubiquitous secondorder phase transition.Our theory and experiment show that the single threshold second-order phase transition is only a special case of the more general multi-threshold second-order phase transition,which is an even richer phenomenon.     

Flame spread over the surface of thermal insulation materials in different environments

Experiments were conducted in a plateau area in Lhasa and a plain area in Hefei China to investigate the flame spread characteristics on thermal insulation materials under different environmental conditions (pressure and oxygen concentration).Molded polystyrene foam (EPS) and extruded polystyrene foam (XPS) samples were placed horizontally on a small-scale flame spread experimental bench.Changes in the average length of the pool fire,flame spread speed,average flame height,and length of preheating zone were used to determine the effect of the plateau and plain environments on flame spread characteristics.These parameters were all larger in Hefei than in Lhasa,which indicates the fire hazard in Hefei will be higher than that in Lhasa if insulation materials of the same size are used.     

Membrane sorption property effects on transmembrane permeation

A theoretical study was carried out into membrane transport phenomena.Formulae for calculating the membrane transport resistance and transmembrane mass flux were given,variations in membrane resistance and moisture flux with the membrane sorption constant(C)under various humidity conditions were analyzed,and the value of C corresponding to the minimum membrane resistance or the maximum moisture flux was obtained.The results show that the membrane resistance and moisture flux relate not only to C but also to the relative humidities on both sides of the membrane.As C increases,membrane resistance initially decreases but then increases,i.e.,a minimum occurs,while the moisture flux first decreases and then increases,i.e.,a maximum occurs.The membrane resistance and moisture flux reach their extrema at the same value of C,which is determined by the relative humidities on both sides of the membrane.To reduce the membrane resistance,the value of C should be chosen based on the humidity conditions.     

Superfluid density of two-dimensional weakly interacting boson system at zero temperature

We compute the superfluid density of a two-dimensional boson system with weak two-body repulsive interactions at zero temperature using one-loop perturbation theory in the weak coupling region. The boson fields are taken to be in continuum form in real space, and the interactions are approximated by a δ function of the distance between the bosons. We find that the one-loop fluctuations slightly decrease the superfluid density of a classical level. The superfluid density is approximated by the condensate density multiplied by the mass of the boson particle.     

Upwind finite volume element methods for one-dimensional semiconductor device

A fully discrete implicit Euler upwind finite volume element method is derived and studied for one-dimensional semiconductor device. Upwind scheme is introduced to deal with the convection-dominated diffusion equations in the semiconductor model. With different time steps for the electrostatic potential and the other unknown quantities, the computational procedure of the method is obtained. The local mass conservation laws are preserved under the framework of the upwind finite volume element schemes. A first-order accuracy in the L ²-norm is proved. Numerical experiments are given to validate the usefulness and efficiency of the method.