A CAS Registry Number (CAS RN or CAS Number) is a unique numerical identifier assigned to a specific chemical substance by the Chemical Abstracts Service (CAS), a division of the American Chemical Society. These numbers are used to provide a way to identify chemical compounds, mixtures, and other substances in a standardized format.

Total inorganic carbon (TIC) refers to the sum of all inorganic carbon species present in a given sample. It typically includes: 1. **Carbon Dioxide (CO₂)**: This is a gas dissolved in water that is crucial for aquatic ecosystems and plays a significant role in the carbon cycle.

Marine chemistry is the study of the chemical composition and properties of ocean waters, marine sediments, and the chemical processes that occur in marine environments. It encompasses a range of topics, including: 1. **Composition of Seawater**: Analyzing the salts, nutrients (like nitrates and phosphates), gases (such as oxygen and carbon dioxide), and other dissolved substances present in seawater.

In chess, a "fortress" is a defensive formation or setup that a player creates to prevent the opponent from being able to make progress, often in a situation where one side is at a material disadvantage but can effectively safeguard against losing. This concept is typically relevant in endgames, where one side has an inferior position but can set up a configuration of pieces that makes it impossible for the opponent to break through and force a win.

The European Chemicals Bureau (ECB) was a part of the European Commission that operated under the Directorate-General for Environment. It was primarily responsible for implementing various regulatory frameworks related to chemical substances in the European Union, particularly the REACH (Registration, Evaluation, Authorisation, and Restriction of Chemicals) regulation. The ECB provided technical and scientific support for the development of policies on chemicals and facilitated the registration and assessment of chemical substances.

The European Chemical Substances Information System (ESIS) was a database established by the European Commission to provide information on chemical substances that are manufactured or imported in the European Union (EU). Its main objective was to support the implementation of various European regulations regarding chemical safety, such as the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulation. ESIS contained data on: 1. **Chemical substance identity**: Information on the chemical name, CAS number, and other identifiers.

IUCLID stands for "International Uniform Chemical Information Database." It is a software application developed by the European Chemicals Agency (ECHA) that is used for managing and exchanging information on chemical substances. IUCLID allows users to create, store, and manage data related to the properties and hazards of chemicals, as well as information necessary for regulatory compliance, such as the European Union's REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulation.

Virtual screening is a computational technique used in drug discovery and molecular biology to identify potential drug candidates or to evaluate the binding affinity of small molecules to target proteins. It involves the use of computer algorithms and simulations to analyze large libraries of compounds virtually, rather than physically screening each compound in the laboratory. The process typically involves the following key steps: 1. **Target Selection**: Identifying a biological target, such as a protein or enzyme, that is implicated in a disease or biological pathway.

Sensitivity and specificity are statistical measures used to evaluate the performance of diagnostic tests or screening tools in medicine and other fields. ### Sensitivity - **Definition**: Sensitivity refers to the ability of a test to correctly identify individuals who have a particular disease or condition. It measures the proportion of true positives (correctly identified cases) out of the total number of actual positives (both true positives and false negatives).

Chess strategy refers to the long-term planning and decision-making processes that players use to gain advantages over their opponents. Unlike tactics, which focus on short-term sequences of moves and immediate threats (like forks or discovered attacks), strategy encompasses broader themes and concepts that guide a player's overall approach to the game.

Chess traps are specific sequences of moves that aim to take advantage of an opponent's mistakes or oversights early in the game, often leading to a quick advantage, material gain, or even checkmate. They are typically employed in the opening phase of the game and can occur in various openings or setups.

In chess, "tempo" refers to the concept of time and move efficiency in the game. Each turn in chess is considered a unit of tempo, and gaining a tempo means taking an action that forces your opponent to respond in a way that is less advantageous for them or to spend their turn reacting instead of developing their own plan.

Triangulation in chess is a strategic maneuver used primarily in endgame situations. It involves a player making a series of moves that return their king (or sometimes another piece) to the same position while forcing the opponent to move into a less favorable position. The main purpose of triangulation is to gain the opposition—meaning to place the opponent's king in a position where it is out of squares to move to, thus giving the moving player a strategic advantage.

"Checkmate" is a term commonly used in chess, denoting a situation where a player's king is in a position to be captured ("in check") and there are no legal moves available to remove the threat of capture. When a player announces "checkmate," it signifies the end of the game, with that player being the victor.

China has a long and rich history of mathematics, with contributions from various provinces throughout the centuries. While there may not be a comprehensive list detailing all Chinese mathematicians categorized by province, some of the most notable mathematicians and their associated provinces can be mentioned. Here are a few prominent figures from different regions: 1. **Beijing (北京市)** - **Li Sheng (李盛)**: Known for his work in number theory during the Tang Dynasty.

21st-century Chilean mathematicians have made significant contributions across various fields of mathematics, including but not limited to algebra, analysis, geometry, and applied mathematics. Notable figures include: 1. **Arturo M. C. B. G. M. F. G. G. M. R. S. L. P. R. E. D. G. M. T. T. G. A** - known for his scholarship in algebra and computational mathematics.

Chilean astrophysicists are scientists from Chile who specialize in the study of astrophysics, the branch of astronomy that deals with the physical properties and processes of celestial bodies and the universe as a whole. Chile is known for its significant contributions to the field of astrophysics, largely due to its favorable geographic location and clear skies, which make it an ideal site for astronomical observatories.

Chinese cryptographers refer to individuals or groups in China who specialize in the field of cryptography, which is the study and practice of techniques for secure communication and data protection. Cryptography involves creating and deciphering codes and ciphers, securing information, maintaining confidentiality, ensuring data integrity, and authenticating communications. China has a rich history in cryptography, dating back to ancient times, and in recent years, it has become a major player in modern cryptographic research and development.

Xiaoying Han could refer to various subjects or individuals, but without further context, it's challenging to provide a specific answer. It might refer to a person's name, possibly a notable figure in a particular field, or it could be related to a cultural reference, a work of art, or a concept in a specific discipline.

Chinese bioinformaticians are researchers and professionals in China who specialize in the field of bioinformatics, which combines biology, computer science, mathematics, and statistics to analyze and interpret biological data. This discipline is particularly important in areas such as genomics, proteomics, metabolomics, and systems biology.