Search

Heat pipe radiators are popular as heat dissipation system of electronic components due to high heat transfer efficiency and reliability. This study proposed a metal foam heat pipe radiator to enhance heat transfer between heat pipe condensed section and air. The prototypes of traditional fins and metal foam heat pipe radiator were produced to validate the heat transfer enhancement. The effect of metal foam pore density on the heat dissipation capability was discussed. The experiment results showed that metal foam heat pipe radiator could improve the start-up time and part-load time in comparison with the traditional fins heat pipe radiator. The thermal resistance of proposed radiators could reduce by 10% when the pore density of copper foam is 5 PPI.

The Laser Photothermal Method (LPM), which is a transient non-contact technique, was employed to measure the thermal physical parameters of Stainless Steel 304 (SS304), Oxygen-Free Copper (OFC) and Aluminum Nitride (AlN) ceramics. The thermal diffusivity of SS304, OFC and AlN ceramic were measured by the LPM and some explanations for the tendency with the temperature were given. Compared with the reference values, it showed that the LPM is reliable in measuring thermal parameters. Following, the Thermal Contact Resistances (TCRs) of OFC-AlN ceramic, SS304-AlN, SS304-SS304 and AlN ceramic were measured in the temperature range from 70 K to 300 K and the contact pressure was on the order of 0.10 MPa. Some explanations were given to make clear the changing trend of TCRs with the increase of temperature. Moreover, some empirical formulas of the TCRs were established. The accuracy of the establishing empirical formulas had been validated by the experiment, and the error was smaller than 9%.

Reports on antimicrobial resistance (AMR) of Mycobacterium leprae, relationship with bacteriological index (BI), and transmission in China are limited. We investigated the emergence of AMR mutations, the relationship between BI and AMR in complete, moderate and lack of BI decline cases, and molecular epidemiological features of AMR cases by enrolling 290 leprosy cases from four endemic provinces. Seven (2.41%), one (0.34%), five (1.72%), one (0.34%), and one (0.34%) strains had single mutations in folP1, rpoC, gyrA, gyrB, and 23S rRNA, respectively. Double mutations in folP1 and gyrA, rpoB and gyrA, and gyrA and 23S rRNA were observed in one (0.34%) strain each. Mutated strains occurred in three out of 81 (95% CI−0.005-0.079, p = 0.083) cases with complete BI decline, in seven out of 103 (95% CI 0.018-0.117, p = 0.008) cases with moderate BI decline, and in four out of 34 (95% CI 0.003-0.231, p = 0.044) cases with lack of BI decline. Most of these mutated strains were geographically separated and diverged genotypically. AMR mutations may not be the main cause of the lack of BI decline. The low transmission of AMR strains at the county level indicates an ongoing transmission at close contact levels.