A study of interaction between two He+ ions in terms of the electronic forces

The potential energy curve of the He2+2 system dissociating into two He+ ions is examined in terms of the electronic force exerted on each nucleus as a function of the internuclear separation. The results are compared with the process of bond-formation in H2 from the separated atoms.

Computer simulation of H and He effects in fusion reactor materials

Fusion power is an appealing source of clean and abundant energy. The radiation resistance of reactor materials is one of the greatest obstacles on the path towards commercial fusion power. These materials are subject to a harsh radiation environment, and cannot fail mechanically or contaminate the fusion plasma. Moreover, for a power plant to be economically viable, the reactor materials must withstand long operation times, with little maintenance. The fusion reactor materials will contain hydrogen and helium, due to deposition from the plasma and nuclear reactions because of energetic neutron irradiation. The first wall divertor materials, carbon and tungsten in existing and planned test reactors, will be subject to intense bombardment of low energy deuterium and helium, which erodes and modifies the surface. All reactor materials, including the structural steel, will suffer irradiation of high energy neutrons, causing displacement cascade damage. Molecular dynamics simulation is a valuable tool for studying irradiation phenomena, such as surface bombardment and the onset of primary damage due to displacement cascades. The governing mechanisms are on the atomic level, and hence not easily studied experimentally. In order to model materials, interatomic potentials are needed to describe the interaction between the atoms. In this thesis, new interatomic potentials were developed for the tungsten-carbon-hydrogen system and for iron-helium and chromium-helium. Thus, the study of previously inaccessible systems was made possible, in particular the effect of H and He on radiation damage. The potentials were based on experimental and ab initio data from the literature, as well as density-functional theory calculations performed in this work. As a model for ferritic steel, iron-chromium with 10% Cr was studied. The difference between Fe and FeCr was shown to be negligible for threshold displacement energies. The properties of small He and He-vacancy clusters in Fe and FeCr were also investigated. The clusters were found to be more mobile and dissociate more rapidly than previously assumed, and the effect of Cr was small. The primary damage formed by displacement cascades was found to be heavily influenced by the presence of He, both in FeCr and W. Many important issues with fusion reactor materials remain poorly understood, and will require a huge effort by the international community. The development of potential models for new materials and the simulations performed in this thesis reveal many interesting features, but also serve as a platform for further studies.

Electron donor-acceptor complex of ICl with diethyl ether - He I photoelectron spectroscopy and ab initio molecular orbital study

The He I photoelectron spectrum of the diethyl ether-ICl complex has been obtained. The oxygen orbitals are shifted to higher binding energies and that of ICl to lower binding energies owing to complex formation. Ab initio molecular orbital (MO) calculations of the complex molecule showed that the bonding is between the sigma-type lone pair of oxygen and the I atom and that the complex has C-2v symmetry. The binding energy of the complex is computed to be 8.06 kcal mol(-1) at the MP2/3-21G* level. The orbital energies obtained from the photoelectron spectra of the complex are compared and assigned with orbital energies obtained by MO calculations. Natural bond orbital analysis (NBO) shows that charge transfer is from the sigma-type oxygen lone pair to the iodine atom and the magnitude of charge transfer is 0.0744 e.

Population inversions behind normal shock waves in CO2‐N2‐He mixtures seeded with solid particles: Further results

The analysis of propagation of a normal shock wave in CO2‐N2‐He or H2 or H2O system seeded with solid particles is presented. The variation of translational and vibrational temperatures of gas phase and the particle temperatures in the relaxation zone behind the shock front are given in graphical form. These results show that the peak value of population inversion and the width of the inversion zone are highest for He catalyst and lowest for H2O catalyst.

Out of equilibrium plasticity dynamics and the annealing of supersolidity in solid He-4

We present a numerical study of a continuum plasticity field coupled to a Ginzburg-Landau model for superfluidity. The results suggest that a supersolid fraction may appear as a long-lived transient during the time evolution of the plasticity field at higher temperatures where both dislocation climb and glide are allowed. Supersolidity, however, vanishes with annealing. As the temperature is decreased, dislocation climb is arrested and any residual supersolidity due to incomplete annealing remains frozen. Our results may provide a resolution of many perplexing issues concerning a variety of experiments on bulk solid He-4.

频闪He-Ne激光高速干涉摄影装置

用光振子调制连续输出的He-Ne激光,配合转鼓相机,形成了频闪He-Ne激光高速干涉摄影装置。摄影频率达每秒20000幅。配合超高速转镜相机,可作为超高速干涉摄影的可控同步单脉冲光源。

用脉冲He-Ne激光的分幅高速干涉摄影装置

<正> 用于诊断在透明介质环境中发生的快速、短暂现象的分幅高速干涉摄影装置,已在中国科学院力学研究所研制成功.它是由脉冲He-Ne激光光源、抗强振动的干涉仪及高速摄影机三部分组成.由于装置简单、抗振性好、获得的干涉图片结果直观、使

用He-Ne激光源的分幅高速干涉摄影

<正>用于研究在透明介质环境中发生的快速、短暂现象的分幅高速干涉摄影装置已研制成功,并得到应用.它是由脉冲He-Ne激光源、抗强振动的干涉仪与高速摄影机三部分组成.装置的结构简单、抗振、工作正常,能广泛地用于超音速风洞流场显示、燃烧、爆炸及强激光与物质相互作用等的研究中,能得到一系列清晰的干涉照片.在研制中,首次提出了逆程序运转方案,将连续输出的He-Ne激光器成功地改造成时间可控的脉冲光源.装置中用到了平晶型激光错位干涉仪.这是一种只有一块干涉元件的仪器,成本低,能获得比一般干涉仪大的视场.并且易于调整维护.

Alvará com força de Lei, por que Vossa Magestade he servido ordenar, que a liberdade, que havia concedido aos indios do Maranhão para as suas pessoas, bens, e commercio, pelos Alvarás de seis, e sete de junho de mil setecentos cincoenta e cinco, se estenda na mesma fórma aos indios, que habitão em todo o continente do Brasil, sem restricçaõ, interpretaçaõ, ou modificaçaõ alguma, na fórma, que nelle se declara : para Vossa Magestade ver

Coleção Marcio Moreira Alves.

Alvará com força de Ley, porque Vossa Magestade he servido prohibir, que se possam carregar, nem transportar escravos pretos de hum, e outro sexo dos pórtos da America, Africa, e Asia, para os destes Reinos de Portugal, e dos Algarves ; applicando as penas nelle declaradas a todos os que contravierem a dita Ley, passado o termo de seis mezes, a respeito dos primeiros, e segundos dos referidos pórtos, e hum anno a respeito dos terceiros : tudo na fórma que acima se contém : para V. Magestade ver / Joaquim Joseph Borralho o fez

Ao alto do título: Conde de Oeyras.

Alvará de Ley, por que V. Magestade he servido declarar, que os vassallos deste Reino, e da America, que casarem com indias della, não ficaõ com infamia alguma, antes se faraõ dignos da sua Real attençaõ, e faraõ preferidos nas terras, em que se estabelecerem, para os lugares, e occupações, que couberem na graduaçaõ de suas pessoas; e seus filhos, e descendentes seraõ habeis, e capazes de qualquer emprego, honra, ou dignidade, sem que necessitem de dispensa alguma, em razaõ destas alianças, em que se comprehendem as que já se achaõ feitas antes desta resoluçaõ; e que o mesmo se praticará com os portuguezes, que casarem com indios, e os seus filhos, e descendentes, como assima se declara : para V. Magestade ver

Coleção Marcio Moreira Alves.

Alvará, porque Vossa Alteza Real he servido revogar toda a prohibição, que havia, de fabricas, e manufacturas no Estado do Brazil, e dominios ultramarinos, na forma acima exposta : para Vossa Alteza Real João Alvares de Miranda Varejão o fez

Apresenta o alvará de 12 de abril de 1808, do Príncipe Regente D. João, que revoga o Alvará de 5 de janeiro de 1785, de Maria I, que extinguia a manufatura de tecidos no Brasil.