General manufacturers are available in a variety of sample tubes with 6mm, 9mm and 12mm diameters. The finer the pipe diameter, the smaller the dead volume and the higher the measurement accuracy, but it is more difficult to load the sample. Therefore, according to the sample situation, weigh the pros and cons, use as appropriate.
Reducing cold free space is a consensus among all instrument design and manufacturing personnel. Therefore, when selecting a sample tube, follow the principle of “use the filling rod as much as possible, the sample neck as thin as possible, and the sample chamber as small as possibleâ€.
In addition to this, we need to consider the following factors:
1) Effect of sample morphology: For powder samples, especially low-density powder samples, such as activated carbon, the powder is lifted during vacuuming, which may cause inaccurate analysis results. If the powder is contaminated with O-rings, the system will be caused. Air leaks, once the powder enters the system manifold, will also cause system contamination that is more difficult to repair. Therefore, it is recommended to use tubes with relatively thick necks and relatively large sample compartments for such samples, and filler rods are not recommended. For large particles, high density samples, such as metals, some points
Sub-screens, etc., are less affected by the vacuuming force and do not cause system contamination. Therefore, the selection of the sample tube can directly follow the first principle. “Use as much as possible to fill the rod, as thin as possible, and as small as possible.†.
2) Influence of analysis type: For the pore size analysis of microporous materials, the molecular diffusion rate is slow at low temperatures due to the relatively low initial pressure of the experiment (usually starting from the relative pressure of 10-7/10-6 segments). Gas non-ideality has a large impact on data acquisition, so it is recommended not to use a filler rod to reduce experimental error. For the pore size analysis and specific surface area test of the mesoporous section, the effect of gas non-ideality on data acquisition is minimal, so the use of a packed rod can improve the accuracy of the experimental results.
3) Effect of sample specific surface area: For small specific surface samples, the amount of sample required during the test is large, usually requiring several grams or even ten grams. In this case, in order to ensure the accuracy of the experiment, it should be noted that the sample volume should not exceed 2/3 of the total volume of the sample chamber (straight tube, small ball or large ball). In addition, if the small surface sample also has the characteristics of low density mentioned in 1), it is not recommended to use a filler rod.
The selection experience of the sample tube has the following reference:
The 9mm sample tube is the most commonly used sample tube and is suitable for most samples;
Standard sample tubes for particle samples and conventional specific surface analysis;
Large ball sample tubes are used for powder samples and low surface sample analysis;
A 6mm sample tube is essential for high precision microwell analysis.
Android Face Recognition features
1. Android face identification device adopts the method of locating key areas of the face, which has high accuracy and good security.
2. Generally, a dedicated dual camera is used in 8 Inch Face Recognition, which is a quasi-three-dimensional face recognition technology. The recognition performance greatly exceeds two-dimensional face recognition, and the algorithm complexity is much lower than that of three-dimensional face recognition.3. The recognition performance of biometric Android face recognition is not affected by the ambient light, and the reliability is good.
4. Android face recognition thermometer can upload a list of user names, download access control attendance records, photos and body temperature information via U disk.
8 Inch Android Face Recognition Terminal,Android Face Identification Device,Biometric Android Face Recognition,Android Face Recognition Thermometer
Guangdong Zecheng Intelligent Technology Co., Ltd , https://www.zecheng-security.com