Korea Invisible Mass Search (KIMS) refers to a scientific experiment and collaboration aimed at detecting dark matter, which is a fundamental component of the universe that does not emit, absorb, or reflect light, making it invisible to traditional observational methods. KIMS is primarily focused on using direct detection methods to observe dark matter particles, particularly in the form of Weakly Interacting Massive Particles (WIMPs). The KIMS collaboration operates underground to minimize interference from cosmic rays and other background radiation.

Small-angle scattering (SAS) is a powerful experimental technique used to study the structure of materials at the nanoscale. It is commonly applied in fields such as chemistry, biology, materials science, and condensed matter physics. The technique involves the scattering of X-rays, neutrons, or light (e.g., using small-angle X-ray scattering, or SAXS; small-angle neutron scattering, or SANS; and small-angle light scattering, or SALS) off of a sample.

The Arago spot, also known as the Poinsot spot, is a phenomenon observed in the diffraction pattern of light when it passes through a circular aperture or around a circular obstacle. It is named after the French physicist François Arago, who studied this effect in the early 19th century. When light waves encounter a circular obstacle, they bend around it and create a diffraction pattern.

Fraunhofer diffraction refers to a type of diffraction pattern produced when light waves pass through a slit or around an obstacle and are observed at a considerable distance from the aperture or obstacle, where the incoming and outgoing waves can be treated as parallel. This condition is typically satisfied when the source of light and the observation screen are placed at infinity or sufficiently far away compared to the size of the aperture.

Gas electron diffraction (GED) is a technique used to study the molecular structure of gas-phase samples by examining the scattering of electrons as they pass through a gas. It can be particularly useful for obtaining information about small molecules, radicals, and other transient species that may not have a stable crystalline form or that would be difficult to study using traditional X-ray crystallography.

The Kapitsa–Dirac effect is a quantum phenomenon that occurs when a beam of particles, such as electrons, interacts with a periodic potential in a way that results in the diffraction of the particles into discrete energy states. This effect was first predicted by physicists Peter Kapitsa and Paul Dirac in the 1930s.

Kirchhoff's diffraction formula is a foundational concept in the field of wave optics, specifically addressing the behavior of waves as they propagate from a source and encounter obstacles. Established by the physicist Gustav Kirchhoff in the 19th century, the formula provides a mathematical framework for predicting how light waves will diffract around edges and through apertures.

Momentum transfer refers to the process by which momentum is exchanged between two or more systems, typically involving interactions between particles or bodies. This exchange can occur in various physical contexts, such as collisions, fluid dynamics, and particle physics. In a collision between two objects, for example, momentum transfer occurs as the moving object exerts a force on the stationary object, resulting in a change in their velocities.

Precession Electron Diffraction (PED) is a technique used in electron microscopy to enhance the quality of diffraction data obtained from crystalline materials. It involves the precession of the electron beam around a predetermined axis while the electron diffraction pattern is recorded. Key features of Precession Electron Diffraction include: 1. **Beam Precession**: Instead of maintaining a static electron beam, the beam is rotated or precessed at a specific angle relative to the sample.

STED microscopy, or Stimulated Emission Depletion microscopy, is a super-resolution imaging technique used in fluorescence microscopy. It was developed to overcome the diffraction limit of conventional light microscopy, which typically restricts resolution to about 200 nanometers for visible light. The fundamental principle behind STED microscopy involves the use of two laser beams: 1. **Excitation Beam**: This laser excites fluorescent molecules (fluorophores) in the sample, causing them to emit light.

Ultrasonic grating is a technique that involves the use of ultrasonic waves to create a pattern or grating effect in a medium. This method can be applied in various fields, such as materials science, acoustics, and engineering, and can serve multiple purposes including diagnostics, imaging, and material characterization. In essence, ultrasonic grating works by generating high-frequency sound waves that can propagate through different materials.

XStream Systems is a company specializing in data protection and data transmission solutions, primarily focused on enabling secure access, sharing, and management of sensitive data. They typically provide services and technologies for data encryption, secure file transfer, and data integrity, catering to industries that require robust security measures for handling critical information. Their solutions are designed to help organizations protect their data from unauthorized access and breaches, ensuring compliance with various regulations and standards.

A spin label is a stable free radical used in various fields of scientific research, particularly in electron spin resonance (ESR) spectroscopy and magnetic resonance imaging (MRI). Spin labels are typically small, organic molecules that contain unpaired electrons, which give them magnetic properties. In biological and chemical studies, spin labels are often attached to specific sites in macromolecules, such as proteins or membranes, allowing researchers to study molecular environments, dynamics, and interactions at a molecular level.

Atomic Emission Spectroscopy (AES) is an analytical technique used to identify and quantify elements in a sample based on the light emitted by atoms. The process involves the excitation of atoms, which causes them to emit light at characteristic wavelengths. This emitted light is then analyzed to determine the composition of the sample.

Equivalent width is a measure used in spectroscopy to quantify the strength of spectral lines, such as absorption or emission features in a spectrum. It provides a way to describe how much of the continuum flux is absorbed or emitted by a feature, relative to the continuum level.

The Lyman series refers to a series of spectral lines corresponding to electronic transitions in the hydrogen atom. Specifically, it consists of transitions where an electron moves from a higher energy level (n ≥ 2) down to the ground state (n = 1). These transitions emit ultraviolet light, and the wavelengths of the emitted photons can be calculated using the Rydberg formula.

The hydrogen spectral series refers to the specific wavelengths of light emitted or absorbed by hydrogen atoms when electrons transition between different energy levels. These transitions occur when an electron absorbs energy and moves to a higher energy level (excitation) or when it releases energy and falls back to a lower energy level (emission). The emitted or absorbed light appears in distinct spectral lines, grouped into series corresponding to different electron transitions.

In the context of spectroscopy, "principal series" refers to a specific set of spectral lines that arise from the electronic transitions of atoms or ions, particularly in the hydrogen atom and hydrogen-like systems. These transitions occur between different energy levels characterized by principal quantum numbers. For hydrogen, the principal series typically involves transitions where an electron moves from higher energy levels (n ≥ 2) down to the first energy level (n = 1).

The Rydberg–Ritz combination principle is a concept in the field of spectroscopy that relates to the spectral lines of atoms, particularly hydrogen. It was formulated in the early 20th century based on the work of physicists Johannes Rydberg and Walther Ritz.

Vibrational energy relaxation refers to the process by which vibrational energy, which is the energy associated with the vibrational motion of atoms within a molecule, dissipates or transitions to other forms of energy, typically in a condensed phase or gas. This process is significant in various fields, including physical chemistry, materials science, and biophysics, as it plays a critical role in energy transfer mechanisms, chemical reactions, and the behavior of complex systems.