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science/Science.md

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+---
+tags: ["meta"]
+obj: meta/collection
+---
+# Science Fields
+- [Math](math/Math.md)
+- [Physics](physics/Physics.md)
+- [Chemistry](chemistry/Chemistry.md)
+- [Biology](biology/Biology.md)
+- [Philosophy](philosophy/Philosophy.md)
+- [Psychology](psychology/Psychology.md)

science/biology/Biology.md

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+---
+obj: meta
+---
+
+#wip #🐇 #notnow 

science/chemistry/Chemistry.md

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+---
+obj: meta
+---
+#wip #🐇 #notnow 

science/math/Binary System.md

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+---
+obj: concept
+---
+# Binary System
+The base-2 numeral system is a positional notation with a radix of 2. Each digit is referred to as a bit, or binary digit. Because of its straightforward implementation in digital electronic circuitry using logic gates, the binary system is used by almost all modern computers and computer-based devices, as a preferred system of use, over various other human techniques of communication, because of the simplicity of the language and the noise immunity in physical implementation.
+
+Negative numbers are commonly represented in binary using two's complement.
+
+## Two's complement
+Two's complement of an integer number is achieved by:
+- Step 1: Start with the absolute value of the number.
+- Step 2: inverting (or flipping) all bits – changing every 0 to 1, and every 1 to 0;
+- Step 3: adding 1 to the entire inverted number, ignoring any overflow. Accounting for overflow will produce the wrong value for the result.
+
+For example, to calculate the decimal number **−6** in binary:
+- Step 1: _+6_ in decimal is _0110_ in binary; the leftmost significant bit (the first 0) is the sign (just _110_ in binary would be -2 in decimal).
+- Step 2: flip all bits in _0110_, giving _1001_.
+- Step 3: add the place value 1 to the flipped number _1001_, giving _1010_.
+
+To verify that _1010_ indeed has a value of _−6_, add the place values together, but _subtract_ the sign value from the final calculation. Because the most significant value is the sign value, it must be subtracted to produce the correct result: **1010** = **−**(**1**×23) + (**0**×22) + (**1**×21) + (**0**×20) = **1**×−8 + **0** + **1**×2 + **0** = −6.
+
+| Bits:                | 1               | 0          | 1          | 0          |
+| -------------------- | --------------- | ---------- | ---------- | ---------- |
+| Decimal bit value:   | **−**8          | 4          | 2          | 1          |
+| Binary calculation:  | **−**(**1**×23) | (**0**×22) | (**1**×21) | (**0**×20) |
+| Decimal calculation: | **−**(**1**×8)  | **0**      | **1**×2    | **0**      |

science/math/Decimal System.md

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+---
+obj: concept
+wiki: https://en.wikipedia.org/wiki/Decimal
+---
+# Decimal System
+The decimal numeral system (also called the base-ten positional numeral system and decanary) is the standard system for denoting integer and non-integer numbers. It is the extension to non-integer numbers (decimal fractions) of the Hindu–Arabic numeral system. The way of denoting numbers in the decimal system is often referred to as decimal notation.
+
+A decimal numeral (also often just decimal or, less correctly, decimal number), refers generally to the notation of a number in the decimal numeral system. Decimals may sometimes be identified by a decimal separator (usually "." or "," as in 25.9703 or 3,1415). Decimal may also refer specifically to the digits after the decimal separator, such as in "3.14 is the approximation of π to two decimals". Zero-digits after a decimal separator serve the purpose of signifying the precision of a value.
+
+The decimal system uses the following symbols: `0`, `1`, `2`, `3`, `4`, `5`, `6`, `7`, `8`, `9`

science/math/Hexadecimal System.md

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+---
+obj: concept
+---
+# Hexadecimal System
+The hexadecimal numbering system, often referred to as "hex," is a base-16 numeral system widely used in computing and digital electronics. It provides a convenient way to represent binary-coded values with a more human-friendly and compact notation. In the hexadecimal system, numbers are represented using 16 different digits: 0-9 and A-F, where A stands for 10, B for 11, and so on up to F for 15.
+
+## Representation
+In hexadecimal, each digit represents a power of 16. The rightmost digit represents $16^0$ (1), the next digit to the left represents $16^1$ (16), the next $16^2$ (256), and so forth. For example:
+
+- **1F in hexadecimal** is equal to $1×16^1+15×16^0$, which is 31 in decimal.
+- **2A3 in hexadecimal** is equal to $2×16^2+10×16^1+3×16^0,$, which is 675 in decimal.
+
+## Hexadecimal Digits
+The hexadecimal system uses the following digits:
+
+- **0, 1, 2, 3, 4, 5, 6, 7, 8, 9**: Represent values 0 to 9.
+- **A, B, C, D, E, F**: Represent values 10 to 15.
+
+## Uses in Computing
+### Memory Addresses
+In computer programming, memory addresses are often expressed in hexadecimal. Each byte of memory can be represented by two hexadecimal digits, providing a concise way to denote memory locations.
+`Example: 0x1A3F`
+
+### Color Representation
+Hexadecimal is commonly used to represent colors in web development and digital graphics. In this context, a hexadecimal color code consists of three pairs of digits representing the intensities of red, green, and blue.
+`Example: #FFA500 (RGB: 255, 165, 0)`
+
+### Binary Representation
+Hexadecimal is closely related to [binary](Binary%20System.md) representation. Each hexadecimal digit corresponds to four bits in binary. This relationship makes it easier to convert between hexadecimal and binary.
+`Example: Binary 1010 is equivalent to Hex A.`

science/math/Math.md

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+---
+obj: meta
+---
+# Math
+#wip #🐇 #notnow 

science/philosophy/Philosophy.md

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+---
+obj: meta
+---
+# Philosophy
+#wip #🐇 #notnow 

science/physics/Physics.md

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+---
+obj: meta
+---
+#wip #🐇 #notnow 

science/physics/SI Units.md

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+---
+obj: meta/collection
+---
+
+#wip #🐇 #notnow 
+- [Volt](units/Volt.md)

science/physics/units/Volt.md

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+---
+wiki: https://en.wikipedia.org/wiki/Volt
+obj: science/unit
+---
+# Volt
+The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI).
+
+| Name          | Value         |
+| ------------- | ------------- |
+| Symbol        | V             |
+| SI base units | $$kg⋅m^2⋅s^{-3}⋅A^{−1}$$ |

science/psychology/Psychology.md

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+---
+obj: meta
+---
+# Psychology
+#wip #🐇 #notnow