Liquid nitrogen gasification scanning calorimetry method and liquid nitrogen gasification calorimeter

A scanning calorimetry and liquid nitrogen technology, applied in the field of material thermal property measurement, can solve the problems of high liquid nitrogen consumption, troublesome, time-consuming measurement, etc.

Inactive Publication Date: 2005-03-23
NANJING UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But there are at least two disadvantages: (1) The thermal inertia of the system is large, which often makes the characteristics of the measurement curve passivated and the phase transi

Method used

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  • Liquid nitrogen gasification scanning calorimetry method and liquid nitrogen gasification calorimeter
  • Liquid nitrogen gasification scanning calorimetry method and liquid nitrogen gasification calorimeter
  • Liquid nitrogen gasification scanning calorimetry method and liquid nitrogen gasification calorimeter

Examples

Experimental program
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Effect test

Embodiment 1

[0120] Embodiment 1, liquid nitrogen gasification scanning calorimeter:

[0121] The calorimeter includes an electronic balance 1, a vacuum insulation container 2, a liquid nitrogen addition tube 3, a heat conduction container 4, a sample chamber 5 and a suspension lifting mechanism 6 for the sample chamber. The electronic balance 1 is 500g / 1mg grade; the vacuum insulation container 2 is placed on the weighing pan of the electronic balance, the vacuum insulation container 2 has an inner diameter of 60mm, a depth of 160mm, and a weight of 206.873g, which is Cr 1 Ni 18 Ti 9 Made of stainless steel; the heat conduction container 4 is placed in the vacuum insulation container 2, the heat conduction container 4 is made of copper, the inner diameter is 20mm, the depth is 60mm, and the wall thickness is 0.2mm; the sample chamber 5 is a copper cylinder, the inner diameter of the outer bladder is 13.6mm, and the height is 13.5mm , wall thickness 0.3mm, inner diameter of liner 12.5mm,...

Embodiment 2

[0123] Embodiment 2, using the liquid nitrogen gasification scanning calorimeter described in Example 1, under the condition of no power compensation, adopt the liquid nitrogen gasification scanning calorimetry to test the oxygen-free copper sample (mass 10.99g, diameter 12.5mm, height 10mm cylinder) for specific heat capacity measurements in the temperature range from -190°C to 200°C:

[0124] Step 1. Determining the correction curve:

[0125] 1. Liquid nitrogen is injected into the vacuum insulation container, so that the liquid nitrogen surrounds the heat conduction container placed in the vacuum heat insulation container, but does not enter the heat conduction container, and the sample chamber is suspended in the heat conduction container; the total mass of liquid nitrogen injected is 112g. At this time, the liquid nitrogen The nitrogen surface is about 5mm away from the upper edge of the heat absorber. Before being placed in the sample chamber, the natural gasification r...

Embodiment 3

[0136] Embodiment 3, using the liquid nitrogen vaporization scanning calorimeter described in Example 1, under the condition of no power compensation, adopt the liquid nitrogen vaporization scanning calorimetry to test the gadolinium sample (quality 9.682g, which is 12.5mm in diameter and 10mm in height) Cylinders, purity better than 99.9%) for specific heat capacity measurements over a temperature range of -190°C to 200°C. Measuring method and process are basically the same as embodiment 2, measure and obtain sample temperature change rate-temperature characteristic curve (such as Figure 10 shown), liquid nitrogen mass change rate-temperature characteristic curve (such as Figure 11 shown). Figure 12 The dot in the middle is the specific heat capacity-temperature response curve of the gadolinium sample under the condition of free cooling obtained according to formula (3), and the relevant data shown in the thin line are extracted from Physical Review Letters, Vol.

[0137...

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Abstract

The invention discloses a liquid nitrogen gasification scan heat measuring method and the device. The invention uses process of heat exchange between the sample and the liquid nitrogen, and carries on sample heat measuring; it also discloses two kinds of optimized projects, namely: carries on heat compensation or overheat compensation in the process, in order to upgrade the heat measuring precision. At the same time, the invention also discloses a device based on the method. The invention is simple, quick and accurate, the device is simple, and the consumed nitrogen is little.

Description

technical field [0001] The invention relates to the field of measurement of thermal properties of materials in the temperature range of -190°C to 200°C, in particular to a liquid nitrogen vaporization scanning calorimetry method for measuring the heat change of material samples, and the liquid nitrogen vaporization scanning calorimetry used for implementing the method Thermometer. Background technique [0002] There are several existing techniques for the measurement of heat changes in material samples. Typical steady-state measurements are thermal pulse specific heat measurements in a thermostat under adiabatic or quasi-adiabatic conditions. Typical dynamic measurement methods include thermal diffusion, differential thermal analysis, and differential scanning calorimetry. The common feature of the current calorimetry method is the use of electric heating or radiation heating for calorimetric measurement, and commercial calorimetric instruments that adapt to different tech...

Claims

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Application Information

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IPC IPC(8): G01N25/20G01N25/48
Inventor 高学奎周超文博高健
Owner NANJING UNIV
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