The gas-cooled nuclear reactor combined with the closed Brayton cycle is the ideal choice for future high-power space missions, while the helium-xenon mixture is a suitable working medium for the reactor due to its go...
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Modified Condition/Decision Coverage (MC/DC) is a test coverage standard with excellent fault detection capability, which is widely used in testing safety-critical software. Symbolic execution generates test cases aut...
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Within the operational dynamics of a nuclear reactor, the customary approach involves modulating the reactor's power output by means of control rod manipulation, which effectively alters the neutron density across...
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Enormous studies have demonstrated that suitable modification methods, such as micro-structures machining, are adopted to enhance boiling heat transfer performance, especially critical heat flux (CHF) value. This sign...
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In this paper, a new developed Monte Carlo method code, intended to be used in shielding calculations, will be introduced. This code was developed on the basis of RMC and under the collaboration of the Nuclear Power I...
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The heat pipe is the essential component in the heat pipe cooled reactor, it conducts heat through the phase change of the working medium and the circulating flow of gas and liquid. One end of the heat pipe is inserte...
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ISBN:
(纸本)9780791886502
The heat pipe is the essential component in the heat pipe cooled reactor, it conducts heat through the phase change of the working medium and the circulating flow of gas and liquid. One end of the heat pipe is inserted into the reactor as the evaporation section, while the other end serves as the condensation section connecting to the thermoelectric conversion system. Its heat transfer capacity and temperature distribution under a steady state affect the safety, core temperature and energy conversion efficiency of the heat pipe cooled reactorsystem. Predicting the heat transfer process and steady-state temperature distribution of the heat pipe is helpful to learn about the heat transfer mechanism inside the heat pipe and key factors affecting its performance. It is also helpful to predict the operating characteristics of the heat pipe cooled reactorsystem and improve the performance of the heat pipe. The heat pipe is generally considered to be a heat transfer element with good isothermal properties. Past studies, however, proved the significant quantity of its phase-change thermal resistance, resulting in a temperature difference at the gas-liquid interface of the heat pipe that affects the evaporation and condensation. Studies on the relationship between the temperature difference, the working temperature, and heat transfer power of the heat pipe are conductive to building a heat pipe model, to predict the temperature distribution of the heat pipe in a steady state in a much more accurate manner. This paper offered a heat pipe model that applies the temperature difference of the phase change interface to calculate the evaporation and condensation. Meanwhile, a 1-meter-long sodium heat pipe was adopted to carry out steady-state heat transfer experiments. Measured and computed the temperature difference of the phase change interface of the heat pipe under varying power and temperature and conducted the relational equation as the input of the heat pipe model. The mo
Osmotic pressure is vital to many physiological activities,such as cell proliferation,wound healing and disease ***,how cells interact with the extracellular matrix(ECM)when subjected to osmotic shock remains ***,we v...
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Osmotic pressure is vital to many physiological activities,such as cell proliferation,wound healing and disease ***,how cells interact with the extracellular matrix(ECM)when subjected to osmotic shock remains ***,we visualize the mechanical interactions between cells and the ECM during osmotic shock by quantifying the dynamic evolution of the cell traction *** show that both hypertonic and hypotonic shocks induce continuous and large changes in cell traction ***,the traction force varies with cell volume:the traction force increases as cells shrink and decreases as cells ***,the direction of the traction force is independent of cell volume changes and is always toward the center of the cell-substrate ***,we reveal a mechanical mechanism in which the change in cortical tension caused by osmotic shock leads to the variation in traction force,which suggests a simple method for measuring changes in cell cortical *** findings provide new insights into the mechanical force response of cells to the external environment and may provide a deeper understanding of how the ECM regulates cell structure and function.
The quest for widespread applications especially in extreme environments accentuates the necessity to design materials with robust mechanical and thermodynamic *** all existing materials yield temperature-variant mech...
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The quest for widespread applications especially in extreme environments accentuates the necessity to design materials with robust mechanical and thermodynamic *** all existing materials yield temperature-variant mechanical properties,essentially determined by their different atomic bonding *** general,weak non-covalent interactions are considered to diminish the structural anti-destabilization of covalent crystals despite the toughening ***,starting from multiscale theoretical modeling,we herein reveal an anomalous stabilizing effect in cellulose nanocrystals(CNCs)by the cooperation between the non-covalent hydrogen bonds and covalent glucosidic skeleton,namely molecular levers(MLs).It is surprising to find that the hydrogen bonds in MLs behave like covalent bindings under cryogenic conditions,which provide anomalously enhanced strength and toughness for *** analyses demonstrate that the unique dynamical mechanical behaviors from ambient to deep cryogenic temperatures are synergetic results of the intrinsic temperature dependence veiled in MLs and the overall thermo-induced CNC destabilization/*** the consequence,the variation trend of mechanical strength exhibits a bilinear temperature dependence with~77 K as the turning *** underlying investigations not only establish the bottom–up interrelations from the hydrogen bonding thermodynamics to the crystal-scale mechanical properties,but also facilitate the potential application of cellulose-based materials at extremely low temperatures such as those in outer space.
The nuclear power SVDU in nuclear power plants is an important component of the nuclear reactor protection system. With the complete digitalization of the reactor protection system, the risks of cybersecurity attacks ...
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The radiation generated by nuclear reaction is harmful to human body and equipment,thus the radiation shielding materials that employ the shielding ability from neutron and gamma rays are the best candidates according...
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The radiation generated by nuclear reaction is harmful to human body and equipment,thus the radiation shielding materials that employ the shielding ability from neutron and gamma rays are the best candidates according to application situations and radiation *** this paper,the researches of metal-based neutron and gamma rays or multiple purpose shielding materials are systematically summarized,and the respective and principal problems of these materials with respect to shielding effectiveness and other performances,such as corrosion,mechanical properties,manufacture,etc.,are ***,the prospect of shielding materials is outlined,which suggests that the development of highly efficient and multiply functional radiation shielding materials with good environmental compatibility is one of the future development trends.
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