磁気浮揚を用いて固体と液体の密度を測定する: 基礎知識
Katherine A Mirica1, Sergey S Shevkoplyas, Scott T Phillips
1Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
Journal of the American Chemical Society
|July 23, 2009
まとめ
この研究では,固体と液体の密度を正確に測定するための磁気浮揚システムを導入しています. この革新的な技術は,少量のサンプルでも高い精度で分析能力を向上させています.
科学分野:
- アナリティカル・ケミストリー (Analytical Chemistry) とは
- マテリアルサイエンス 材料科学
- 物理 物理学 物理学とは
背景:
- 正確な密度決定は,材料の特徴化と品質管理に不可欠です.
- 密度測定のための伝統的な方法は,時間がかかり,より大きなサンプル量を要求する可能性があります.
- マイクロスケールサンプルに適用できる高精度,多用途の密度測定技術が必要である.
研究 の 目的:
- 精密な密度測定のために磁気浮揚を利用した分析システムを開発し,検証する.
- 磁気浮揚技術の正確性と適用性を評価するために,様々なサンプルタイプとボリュームについて.
- 固体および水と混合できない有機液体の密度測定のための新しい方法を開発する.
主な方法:
- このシステムは,重力場に沿った2つの対極の永久ネオジミウム磁石 (NdFeB) を採用しています.
- パラマグネット媒介 (例えば,MnCl2溶液) は,磁石の間に置かれた容器内に使用されます.
- サンプルの密度は,磁気力と重力のバランスによって影響される垂直位置を測定することによって決定されます.
主要な成果:
- 磁気浮揚システムは, +/- 0.0002 から +/- 0.02 g/cm の精度を達成します.
- このテクニックは,0.8-3g/cmの密度を持つサンプルに有効です.
- 1 pLから1 mLまでのサンプル容量に適用され,球形と不規則な形の両方に対応します.
結論:
- 磁気浮揚は,密度測定のための非常に正確で敏感な方法を提供します.
- システムの汎用性により,幅広い固体と液体のサンプルに適しています.
- このテクニックは,密度決定のためのマイクロスケール分析測定における重要な進歩を提供します.
関連する概念動画
Density and Archimedes' Principle
When a lump of clay is dropped into water, it sinks. But if the same lump of clay is molded into the shape of a boat, it starts to float. Because of its shape, the clay boat displaces more water than the lump and experiences a greater buoyant force, even though its mass is the same. The same holds true for steel ships. The average density of an object majorly determines if the object will float. If an object's average density is less than that of the surrounding fluid, it will float. The reason...
Density
Density is an important characteristic of substances, crucial in determining whether an object sinks or floats in a fluid. Its SI unit is kg/m3, and its cgs unit is g/cm3. The density of an object helps in identifying its composition, and also reveals information about the phase of the matter and its substructure. The densities of liquids and solids are roughly comparable, consistent with the fact that their atoms are in close contact. However, gases have much lower densities than liquids and...
Magnetic Damping
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
Magnetic Fields
A moving charge or a current creates a magnetic field in the surrounding space, in addition to its electric field. The magnetic field exerts a force on any other moving charge or current that is present in the field. Like an electric field, the magnetic field is also a vector field. At any position, the direction of the magnetic field is defined as the direction in which the north pole of a compass needle points.
A magnetic field is defined by the force that a charged particle experiences...
A magnetic field is defined by the force that a charged particle experiences...
Density, Specific Weight, Specific Gravity and Compressibility of Fluid
Density, specific weight, specific gravity, and compressibility are fundamental properties of fluids. Density is the mass per unit volume, characterizing the mass of a fluid system. It influences buoyancy, pressure, flow dynamics, viscosity, thermal conductivity, and sound propagation. For instance, in pipeline design, accurate density measurements ensure that the pipeline can handle the fluid's mass.
Specific weight represents the weight per unit volume and is calculated by multiplying density...
Specific weight represents the weight per unit volume and is calculated by multiplying density...
Magnetic Force
In addition to the electric forces between electric charges, moving electric charges exert magnetic forces on each other. A magnetic field is created by a moving charge or a group of moving charges known as the electric current. A magnetic force is experienced by a second current or moving charge in response to this magnetic field. Fundamentally, interactions between moving electrons in the atoms of two bodies produce magnetic forces between them.
The magnetic force acting on a moving charge...
The magnetic force acting on a moving charge...


