The existence of the , suggested by in 1916 for group 1 and 2 salt-like hydrides, was demonstrated by Moers in 1920 by the electrolysis of molten LiH , producing a quantity of hydrogen at the anode. Atomic hydrogen has investigated the use of atomic hydrogen as a. Total number of papers does not account for the quality of scientific publications, while total number of citations can be disproportionately affected by participation in a single publication of major influence for instance, methodological papers proposing successful new techniques, methods or approximations, which can generate a large number of citations , or having many publications with few citations each. Hydrogen was for the first time by in 1898 by using and his invention, the. The process also produces , but the expensive gallium, which prevents the formation of an oxide skin on the pellets, can be re-used. The study of their properties is known as and their study in the context of living is known as.
The incident was broadcast live on radio and filmed. It is used in nuclear fusion reactions, as a tracer in , and in specialized devices. Some customers may not qualify. Typically the cathode is made from platinum or another inert metal when producing hydrogen for storage. Archived from on 24 February 2008. However, later work has shown that since h-index is a cumulative measure, it contains intrinsic auto-correlation that led to significant overestimation of its predictability.
Annual Review of Energy and the Environment. On average across the disciplines, a professor in the social sciences had an h-index about twice that of a lecturer or a senior lecturer, though the difference was the smallest in geography. McKetta; William Aaron Cunningham, eds. First tracks observed in at the There exist two different diatomic molecules that differ by the relative of their nuclei. As the only neutral atom for which the can be solved analytically, study of the energetics and bonding of the hydrogen atom has played a key role in the development of.
Millions of are known, and they are usually formed by complicated synthetic pathways that seldom involve elemental hydrogen. From July 2011 have provided an automatically-calculated h-index and within their own profile. These properties may be useful when hydrogen is purified by passage through hot disks, but the gas's high solubility is a metallurgical problem, contributing to the of many metals, complicating the design of pipelines and storage tanks. Numbers are very different in social science disciplines: The Impact of the Social Sciences team at found that social scientists in the United Kingdom had lower average h-indices. The h-index is intended to measure simultaneously the quality and quantity of scientific output. As these metrics are percentages, they are intended to give a qualitative description to supplement the quantitative h-index. Some customers may not qualify.
Under the , acids are proton donors, while bases are proton acceptors. Harzing's Publish or Perish program calculates the h-index based on entries. It has been suggested that in order to deal with the sometimes wide variation in h for a single academic measured across the possible citation databases, one should assume false negatives in the databases are more problematic than false positives and take the maximum h measured for an academic. Isotopes Protium, the most common of hydrogen, has one proton and one electron. Bulletin of the Atomic Scientists. At , hydrogen is a , , , non-toxic, , highly with the H 2.
He produced the next year. Applications Consumption in processes Large quantities of H 2 are needed in the petroleum and chemical industries. Most hydrogen is in the form of atomic hydrogen because the atoms can seldom collide and combine. In more recent applications, hydrogen is used pure or mixed with nitrogen sometimes called as a for minute leak detection. Diatomic gases composed of heavier atoms do not have such widely spaced levels and do not exhibit the same effect.
Formation in transformers From all the fault gases formed in power , hydrogen is the most common and is generated under most fault conditions; thus, formation of hydrogen is an early indication of serious problems in the transformer's life cycle. During the early study of radioactivity, various heavy radioactive isotopes were given their own names, but such names are no longer used, except for deuterium and tritium. Hydrogen is highly soluble in many and and is soluble in both nanocrystalline and. Archived from on 2 March 2008. Most hydrogen is used near the site of its production, the two largest uses being processing e. The index can also be applied to the productivity and impact of a as well as a group of scientists, such as a department or university or country. Anaerobic corrosion Under anaerobic conditions, and are slowly oxidized by the protons of water concomitantly reduced in molecular hydrogen H 2.
Hydrogen's rarer isotopes also each have specific applications. Hydrogen provided the lift for the first reliable form of air-travel following the 1852 invention of the first hydrogen-lifted airship by. Annual Review of Physical Chemistry. This function is particularly common in , especially in hydrides and complexes, as well as in clustered. These compounds are often known as. In , hydrogen can take the form of a negative charge i. Are you looking for a blast of efficiency? During the period January 1, 2000 — February 28, 2010, a physicist had to receive 2073 citations to be among the most cited 1% of physicists in the world.