Adhesion-diffusion formation of a multilayer wall for the liquid metal flow channel of a fusion reactor blanket

A technique for calculating the adhesion-diffusion formation of a multilayer metal-ceramic structure is presented. The development of this technique is dictated by requirements imposed on the wall of the liquid metal flow channel of a fusion reactor blanket. The parameters of the adhesion-diffusion process (pressure, temperature, hold-up time, and the physical properties of materials) are related to the strength characteristics of the resulting composite (incompleteness of the adhesion contact, adhesion energy, and energy and strength of cohesion). Results are illustrated by calculating the formation parameters of the multilayer metal-ceramic structure and its strength as applied to the fusion reactor liquid-metal blanket.     

聚变堆液态包层提氚鼓泡器的概念设计

在气-液接触法提取液态锂合金中的氢的实验基础上,提出了以气-液交换柱为核心的提氚鼓泡器(LBTB)的概念设计。LBTB 主要由气体进样纯化器、气-液交换柱系统、饱和器－解吸器和辅助系统构成。LBTB以氩氢混合气为吹洗气,其主要功能是在线监测液态包层主回路中的氚行为,并检验多柱级联后的氚回收率是否可以达到90%的期望值。     

�۱��Һ̬������밹������ĸ������

在气-液接触法提取液态锂合金中的氢的实验基础上,提出了以气-液交换柱为核心的提氚鼓泡器(LBTB)的概念设计。LBTB 主要由气体进样纯化器、气-液交换柱系统、饱和器－解吸器和辅助系统构成。LBTB以氩氢混合气为吹洗气,其主要功能是在线监测液态包层主回路中的氚行为,并检验多柱级联后的氚回收率是否可以达到90%的期望值。     

聚变堆液态包层准二维磁流体湍流模型研究

为研究聚变堆氚增殖包层中液态金属湍流磁流体动力学(MHD)效应,开发了一种新的准二维单方程 MHD 湍流模型,并进行了相关数值模拟程序的编制及验证。对于矩形管道中的准二维 MHD 湍流流动,三维流 动主要发生在哈德曼层中,中心的主流区呈现出二维流动。为了反映这种特殊的流动特征,新湍流模型在标准 k-ε 模型的基础之上去掉了传统的耗散项,代之以电磁耗散项来模拟湍流 MHD 效应。同时,采用 Bradshaw 假设来对 湍流涡粘系数进行模化。为验证该湍流模型是否合理,编制了相关数值模拟程序,并利用直接数值模拟(DNS)结 果对该程序进行了校正,数值模拟结果与 DNS 结果吻合较好。计算结果表明,该湍流模型可应用于聚变堆液态 包层 MHD 湍流流动的数值模拟。     

A note on the heating of the cold plasma blanket in a linear fusion reactor

On the basis of a simple model it is demonstrated that the Q-factor of present-day conceptual linear reactors is not enhanced by -particle heating of the cold plasma blanket surrounding the fusioning plasma column.     

聚变堆液态包层增殖区铅锂与氦气多流场耦合换热特性研究

采用三维计算流体动力学(CFD)方法对聚变堆液态包层增殖区高温液态铅锂与结构内高压氦气耦合换热进行数值模拟。建立了充放式高压氦气回路和换热实验段,开展了包层典型工况下液态铅锂与氦气多流场耦合换热对比实验验证。研究了氦气压力和增殖区铅锂入口温度、核热功率密度变化时的流动与传热特性及其影响规律,获得了氦气与RAFM钢壁面、液态铅锂与RAFM钢壁面之间的换热系数和换热关联式,为液态包层的设计研发提供了参考依据。     

基于垂直磁场压缩的EAST等离子体初步研究

基于等离子体参数随大半径/小半径变化的规律,分析了电流平顶段垂直磁场与相关等离子体参数的关系。垂直磁场的非线性部分用于分析非感应电流驱动效应,包括自举电流效应。此外,对于给定的等离子体电流,推导了平顶段垂直磁场与线平均密度之间的关系,并进一步研究压缩后的等离子体。基于EAST第41195次放电的数据分析表明,垂直磁场强度的增大可以使得等离子体温度、密度、β_p和自举电流份额获得提升,为等离子体参数高参数,特别是β_p提供了一种可能性参考。     

On the behavior and stability of a liquid metal in quasi-planar electric contacts

The contacts between conductors formed under relatively low pressures can be treated as quasi-planar. Melting of the material of such contacts upon the passage of electric current is used in some technological processes, but the behavior of liquid in these conditions has not been analyzed. In this study, such an estimate was obtained for specific conditions appearing under electric-pulse compacting (briquetting) of metal shavings. Analysis of derived relations shows that this estimate is valid for any quasi-2D contacts upon passage of a pulsed current of duration from microseconds to milliseconds. It is shown that the spacing between contact surfaces decreases, the liquid metal is extruded in the lateral directions, and the area of the contact and its conductivity increase. Sausage-type magnetohydrodynamic (MHD) instability and overheating instability do not evolve in these conditions because the instability wavelength is larger than the rated thickness of the molten layer; screw MHD instability can appear in slower processes.     

Effects of a liquid lithium curtain as the first wall in a fusion reactor plasma

This paper explores the effect of a liquid lithium curtain on fusion reactor plasma, such curtain is utilized as the first wall for the engineering outline design of the Fusion Experimental Breeder （FEB-E）. The relationships between the surface temperature of a liquid lithium curtain and the effective plasma charge, fuel dilution and fusion power production have been derived. Results indicate that under normal operation, the evaporation of liquid lithium does not seriously affect the effective plasma charge, but effects on fuel dilution and fusion power are more sensitive. As an example, it has investigated the relationships between the liquid lithium curtain flow velocity and the rise of surface temperature based on operation scenario II of the FEB-E design with reversed shear configuration and high power density. Results show that even if the liquid lithium curtain flow velocity is as low as 0.5 m/s, the effects of evaporation from the liquid lithium curtain on plasma are negligible. In the present design, the sputtering of liquid lithium curtain and the particle removal effects of the divertor are not yet considered in detail. Further studies are in progress, and in this work implication of lithium erosion and divertor physics on fusion reactor operation are discussed.[第一段]     

Determination of adhesive forces in multilayer materials using a laser adhesiometer

A laser adhesiometer is developed to determine the adhesive and cohesive forces in multilayer materials. The obtained experimental dependences are explained using the laser microexplosion model. The advantages of determining the adhesive and cohesive forces using the laser adhesiometer over other methods are grounded.     

Stressed state of the electrical insulation barrier in the wall structure of a thermonuclear reactor liquid-metal blanket

A technique for analytic determination of normal and tangential stresses in the three-layer structure of a multilayer wall of a flow-through part of thermonuclear reactor liquid-metal blanket is developed. The results of computational analysis of the influence of elastic properties of materials and geometric parameters of the layers on their stressed state are considered.     

液相基质中重金属元素激光诱导击穿光谱实验参数的优化

针对混合溶液中重金属元素的激光诱导击穿光谱(LIBS)测量系统,为提高测量系统的检测灵敏度,以提高混合溶液中Ca和Cr金属元素LIBS光谱线强度的信噪比为目标,对LIBS测量系统中的激光脉冲能量、液相样品流速、ICCD门宽、延时等实验参数进行了优化,得到最优化参数激光脉冲能量、样品流速、ICCD门宽、延时分别为35 m J、30 ml/min、1400 ns和2400 ns,为降低LIBS技术应用于混合溶液中痕量重金属元素的检出限提供了实验参数支撑.     

Theoretical modeling of hard X-ray surface modes in a periodic multilayer

The excitation of hard X-ray surface modes of a periodic multilayer is studied with the help of theoretical modeling. It is found that a hard X-ray surface mode can appear in a specific periodic multilayer coated with a high-density reflecting layer. The generation of the hard X-ray surface modes is shown to be effective only at a certain set of the structural parameters of the multilayer. A method for the calculation of the propagation (attenuation) length of the surface mode running in the periodic multilayer is described. The excitation of the hard X-ray surface modes is compared with that of optical surface modes in photonic crystals. The relationship between the surface modes and guided modes of periodic multilayers is discussed.     

亚热带自然林与人工林土壤重金属含量的研究

重金属是危害森林生态健康主要污染物之一.采用电感耦合等离子体发射光谱法与石墨炉原子吸收光谱法,首次比较了亚热带人工林和自然林土壤中13种重金属元素(Fe,Al,Ti,Cr,Cu,Mn,V,Zn,Ni,Co,Pb,Se,Cd)的含量.结果表明自然林土壤中Fe,Al,Ti,Cu,Mn,V,Zn,Ni,Co,Pb,Se,Cd...     

Formation of multilayer strained-layer heterostructures by liquid epitaxy. I. Theoretical aspects of the problem and mathematical model

Problems concerned with the formation of multilayer strained-layer heterostructures by “capillary” liquid-phase epitaxy with forced hydraulic replacement of the solutions in the growth channel are analyzed. It is shown for short contact times between the solutions and the crystallization surface that the character of their flow in the channel plays an important role in the achievement of uniformity in the physical characteristics of the layers grown. Theoretical estimates of the hydrodynamic stability of solutions moving in narrow channels are performed for several III-V systems. A mathematical model, which permits simulation of the conditions under which strained-layer heterostructures are fabricated, is developed. It takes into account diffusive and convective mass transport in the liquid for various flow regimes in the capillary and the displacement of the heterogeneous equilibria in the system under the influence of elastic stresses. Zh. Tekh. Fiz. 67, 42–49 (July 1997)     

Numerical simulation of liquid velocity distribution in a sonochemical reactor

Ultrasonically induced flow is an important phenomenon observed in a sonochemical reactor. It controls the mass transport of sonochemical reaction and enhances the reaction performance. In the present paper, the liquid velocity distribution of ultrasonically induced flow in the sonochemical reactor with a transducer at frequency of 490 kHz has been numerically simulated. From the comparison of simulation results and experimental data, the ultrasonic absorption coefficient in the sonochemical reactor has been evaluated. To simulate the liquid velocity near the liquid surface above the transducer, which is the main sonochemical reaction area, it is necessary to include the acoustic fountain shape into the computational domain. The simulation results indicate that the liquid velocity increases with acoustic power. The variation of liquid height also influences the behavior of liquid velocity distribution and the mean velocity above the transducer centre becomes a maximum when the liquid height is 0.4 m. The liquid velocity decreases with increasing the transducer plate radius at the same ultrasonic power.     

Characteristic features of microcontact spectra of contacts between a metal and a quasi-1D conductor with a charge density wave

The current-voltage characteristics (IVCs) of Cu−K_0.3MoO₃ point contacts are investigated. The character of the nonlinearity and the observed asymmetric features of the IVCs indicate that a substantial shift of the chemical potential occurs near the boundary with the normal metal. Deformation of the charge density wave by an applied electric field leads to strong bending of the energy bands and to the formation of a potential well, whereupon the Fermi level falls within the region of allowed single-electron states. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 2, 146–151 (25 January 1998)