Robert Rooke, in 1665, was one of the first ones to establish relations between the form of a crystal and its crystalline structure. Structure, in ampler direction, means: Organization of the parts or the elements that form one all. In 1784, Ren Hay, gave a step beyond Hooke and considered that the crystals could be understood as a wrapping up of rombodricas units that it called of ' ' molecules integrantes' '. A crystal currently is defined as a solid with its atoms arranged in three-dimensional periodic reticulado. The arrangement most steady apreesenta the following characteristics: – It groups atoms more compactly possible. – The electric neutrality Preserves. – The character directional of the covalentes linkings Satisfies.
– It minimizes repulses between ons. With the diverse studies concerning the relation between the crystalline structures and solids, it allows to say that the structure of the majority of solids is crystalline. However nor all the solids are crystalline. The glasses and the resins termorgidas, for example, are amorphous. The liquid crystals, that are nothing more than, little thick liquids also exist that present long molecules and that can be lined up parallel as in a crystal. The elastic constants, constant optics, electric condutividade, thermal condutividade, thermal dilatao and even though the chemical reactivity, depend on the crystalline orientation of the material. Moritz Frankenheim, was the first one to develop a systematic work describing and enumerating the space reticulados ones, however, it errneamente counted 15 reticulados space ones. Auguste Bravais, mathematician and French professor of physics, showed that Frankenheim counted two reticulados cristalograficamente equivalents doubly.
Space reticulado is an infinite, three-dimensional arrangement, points and in which all point has the same neighborhood and if calls reticulado point. As Bravais the points of the reticulado one can be associates in 14 different ways, involving 7 called systems Systems of Bravais, they are: – Cubical System: Simple, of Centered Body, Centered Faces. – Tetragonal System: Simple, of Centered Body. – Ortorrmbico System: Simple, of Centered Body, Centered Base, Centered Faces. – Rombodrico- System Hexagonal- System System Monoclnico: Simple, of Centered Base. – TriclnicoVrios elements presents in the solid state different crystalline structures. The denomination for that is allotropy. When the solid is a composed substance, the habitually used denomination is polimorfismo. These changes of structures generally occur in function of variations of temperature and pressure. The study of the crystalline structures and the knowledge of the characteristics of the reticulados ones of Bravais they allow to the planning and the understanding of the properties that certain materials have or will have. The study of the crystalline structures it is part of the Science of the Substances.
Facua gentlemen: I received a great disappointment for you thought trying to users of a humane and independent way but that is what you receive in return an email auto transponder, if a person makes a complaint what you least want is receiving a message from a machine what you want is to receive a message of support and human. The I will tell you one thing, I am not a smoker, but throughout this campaign are doing, does not seem correct, are they attempting with private establishments, that on the one hand, instead of arming both stir with the weakest as always because you’re not going against tobacco companies? (do you know the content that has tobacco to hook even more the smoker?) Because does not say the Government it subsidize drugs for who wants to quit smoking? You are not being fair or realistic, because if they are reported just a little a person in a city it is exposed to breathing 3 times more than what can disturb smoke in a private establishment emphasize private establishment that wants to say that the owner has rights. To finish Lords of Facua always I have been at your side but I see that you guys put chest as all organisms; Better would be that ye preocuparais of the worker, of the unemployed, who does not have to eat, there is where you have to remove chest and face in situations that concern for truth, where you are in these scenarios? The Government has banned and you have already supported it will see the impact that will have this summer in Spain when tourism from outside do not choose Spain as a target, since we had accustomed to tourists to make their holidays without taboos in his country. Nothing more to add to that, we’ll see how many families more you and the governments send unemployment by this prohibition. Thank you original author and source of the article
First of all, you need to know the location of the upcoming exhibition, the travel time from tsetra city subway stations. Also, you must be aware of urban transport and taxis that pass close to the passing show, a convenient parking place, to assess the coming challenges for the delivery and unloading, loading artifacts exhibition stenda.Osoboe attention should be paid to the exhibition itself – what is its size (big or not), the number of exhibition halls (it should analyze the possible conversions of visitors between the pavilions), a place lined booths, the number of passes in each room. All of this information played no role in the analysis of such moments: the "definition in which you want to participate; adjustment (if necessary) advertising campaign, depending on the location of the stand in Hall, the availability of competing companies, and their possible proximity to the stand, identifying the type and size of the stand, which will predsavlyat company on vystavke.To is, the territory of the exhibition and its location are in many cases the main point for subsequent action. for the location of the mobile stand is the place: the right of the entrance, the central part of the exhibition area closest to the entrance, the time for design and construction of an attractive booth, as well as installation time, at the intersection of the main passages. Regardless of where and how to build your stand for the successful development of interest among the visitors to know, and the next rule. Main – this rule of "three seconds". The essence of this rule is that the visitor rather than seconds, that he saw your booth and decided to visit it or pass on. To a man, who came to exhibit, your booth noticed, you need to effectively use a variety of lighting effects, moving parts and colorful printing industry. That is, the use of unusual titles that are easy to read but remain in memory, colorfully and tastefully decorated..