Mass spectrometry was used to sequence peptides for the first time in 1959 when K. Biemann described an innovative method based on the reduction of small peptides to polyamino alcohols with characteristic EI spectra. [https://doi.org/10.1021/ja01518a069]
The particle carries one elementary charge, the value of which is 1.602 176 634 × 10−19 C (exactly).
In the spectrographs used by Thomson until 1910, the rays of positive electricity were detected by the phosphorescence they produced on a willemite screen. The screen was made by grinding rare zinc mineral willemite into a fine powder. After shaking in alcohol, the suspension was allowed to deposit slowly on a glass plate. Later, a photographic plate inside the spectrograph was used for more sensitive detection.
The magnetic force is perpendicular to the velocity so that it does no work on the charged particle. The particle’s kinetic energy and speed thus remain constant. The direction of motion is affected but not the speed.
Aston is a 44-kilometer lunar impact crater located along the northwestern limb of the Moon. The crater was named in honor of Francis W. Aston.
The first mass spectrometer in the country was built in the Laboratory of Physical Chemistry of the Czechoslovak Academy of Sciences. Four young scientists, Vladimír Čermák, Vladimír Hanuš, Čestmír Jech and Josef Cabicar, took part in its construction. At the time of the post-war shortage, it was very difficult to find the necessary components; some parts originated from captured German military equipment. The mass spectrometer was of the Nier type with simple focusing and 60° magnetic field, pumped by a mercury diffusion pump. The device was completed after two years, in 1953. The construction of this instrument was an extraordinary achievement awarded a year later by the State Prize. [Z. Herman, Chem. Listy 104, 955, 2010]
The parents of John Zelený, Antonín Zelený and Josefa Pitková, came from Křídla, a small village near Žďár nad Sázavou in Austria-Hungary (now the Czech Republic).
The solution of differential equations of this type came from the French mathematician Émile Léonard Mathieu (1835-1890), who studied the mechanical vibrations of the elliptical drumheads.
There are no items in your basket.
This website uses cookies to ensure you get the best experience on our website.