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Power Electronic Systems (PES) is widely used in energy sectors such as renewable energy and aerospace. It is very important to design a reliable PES health monitoring system. This paper provides a new condition monitoring method based on Physics-informed Neural Network (PINN). Although the actual PES has a complex topology and is in a dynamically changing operating environment, the operation process does not violate the circuit physical models. Considering the charge and discharge process in the DC-DC converter, the physical formula is derived through the state-space average method. Then the physical formula is added to the deep learning model of LSTM as prior knowledge, to estimate the degradation parameters of the DC-DC converter. The uncertainty method is used to determine the weighting coefficients for data fitting and physical information fitting tasks. The PINN method can improve the estimation accuracy and generalization ability of the model in the case of limited data, which is conducive to the realization of the condition monitoring of complex PES. It is significant to improve the reliability of new energy vehicles and military equipment.

In Qinghai-Tibet Plateau, the construction of asphalt pavement is one of main reasons for permafrost thawing. To decrease the heat accumulation in permafrost embankment, a new route is proposed by inducing a highly oriented heat conduction in asphalt pavement and accelerating a convective heat release from crushed-rock embankment. On this base, two integrative heat-dissipating structures, named G-IHDS (combination of oriented heat conduction structure and crushed-rock embankment) and R + G-IHDS (combination of heat reflective layer, oriented heat conduction structure and crushed–rock embankment), are designed. The results show that the net annual heat accumulation in an embankment decreases by 16.7% for the G-IHDS and 34.9% for the R + G-IHDS, which results in a temperature reduction in the embankment. For example, the summertime mean temperature on the top of the embankment reduces by 0.66 °C for the G-IHDS and 1.58 °C for the R + G-IHDS. The cooling effect of the G-IHDS is validated against an indoor irradiation test. It can be concluded that the permafrost embankment is expected to be cooled by controlling an integrative heat dissipation in asphalt pavement and a crushed-rock embankment.

In this paper, a new method was proposed to decrease the heat accumulation in permafrost embankment by controlling an oriented heat transfer in asphalt pavement. Two highly oriented heat-induced structures, named G-OHIS (only gradient thermal conductivity) and G+R-OHIS (combined gradient thermal conductivity and heat reflective layer), were designed by using two indexes of summertime daily heat absorption and annual net heat accumulation on the top of embankment. The results showed that the heat absorptions on the top of embankments of the G-OHIS and G+R-OHIS in summer decreased by 9.9% and 23.2% respectively. The annual net heat accumulation on the top of embankment decreased by 6.2% for the G-OHIS and 37.9% for the G+R-OHIS. Moreover, the summertime mean daily temperatures on the top of embankments of the G-OHIS and G+R-OHIS reduced by 0.74 °C and 1.66 °C respectively. The annual temperature difference on the top of embankment reduced by 1.07 °C for the G-OHIS and 1.96 °C for the G+R-OHIS. The effectiveness of the G-OHIS in reducing pavement temperature was validated by an indoor irradiation test. It is expected to reduce permafrost thawing and other pavement distresses caused by permafrost thawing by controlling an oriented heat transfer in asphalt pavement.

In this paper, a highly oriented heat conduction structure of asphalt pavement, with a combination of low thermal conductivity layer and three-layered gradient heat conduction structure, was proposed to reduce pavement temperature and decrease nighttime heat release into the atmosphere in summer. The structure was formed by modifying contrast asphalt pavement by adding different dosages of low thermal conductivity powders to each layer. Also, it made full use of principles of thermal insulation and gradient heat conduction, and extended the scope of thermal gradient in asphalt layers. The results showed that, compared with contrast structure, the highest temperature of upper surface of bottom layer, which was used to represent the average temperature of middle and bottom layers, reduced by 2.3 °C (simulation result) and 2.4 °C (test road result). The average temperatures of middle and bottom layers reduced by 1.6 °C (at 2:30 pm) and 1.5 °C (at 6:00 pm), respectively, which were validated by test road results. Calculations of simulation result displayed that the structure released less 12.1% of heat to the atmosphere during nighttime than contrast structure. According to the results summarized above, it is concluded that the structure has a continuous cooling capacity, and is expected to reduce high temperature rutting of asphalt pavement and help to reduce high air temperature at night.

In order to reduce the solar absorption of pavement and accelerate the downward heat conduction, two bidirectional heat induced structures were designed, one named G-BHIS (only gradient thermal conductivity) and the other named G + R-BHIS (the combination of gradient thermal conductivity and heat reflective layer). Compared with the contrast structure, the heat absorption was reduced by 12.73% for the G-BHIS and 35.02% for the G + R-BHIS, respectively. The heat accumulation within the pavement was reduced by 15.9% for the G-BHIS and 37.6% for the G + R-BHIS, respectively. The coupling effect of the decreased heat absorption and accumulation reduced pavement temperature. The maximum temperature differences, 2.38 °C (for the G-BHIS) and 7.76 °C (for the G + R-BHIS), both appeared at the depth of 4 cm. Rutting results showed that the maximum rutting depth could be reduced by 41.0% for the G-BHIS and 65.0% for the G + R-BHIS, respectively. The two structures are expected to decrease heat accumulation and reduce pavement temperature, and furthermore, reducing rutting.

In order to reduce the solar absorption of pavement and inhibit the downward heat conduction rate inside, two highly oriented heat-induced structures were designed, one named G-OHIS (gradient thermal conductivity) and the other named G + R-OHIS (the combination of gradient thermal conductivity and heat reflective structure). Compared with the contrast structure, the total heat absorption was decreased by 12.7% for the G-OHIS and 35.0% for the G + R-OHIS. Meanwhile, the downward heat conduction rates in the middle and bottom layers of the designed structures were also reduced. The coupling effect of less heat absorption and lower downward heat conduction rate decreased the heat accumulation within the pavement as much as 14.2% for the G-OHIS and 34.0% for the G + R-OHIS. The maximum temperature reduction was 2.47 °C for the G-OHIS and 7.07 °C for the G + R-OHIS. The indoor irradiation test showed a good consistency with the simulation results. Rutting simulation results showed that the maximum rutting depth was reduced by 44.3% for the G-OHIS and 65.0% for the G + R-OHIS. The highly oriented heat-induced structure is expected to be used to reduce pavement temperature and alleviate rutting in summer.

The absorption of solar radiant heat is the primary reason for the high temperature of asphalt pavement and the exacerbation of the urban heat island effect. In this paper, a novel unidirectional heat-transfer (UHT) asphalt pavement structure was proposed, which allows heat transfer along a fixed direction. The UHT effect was demonstrated under lamp lit indoor and sunlit outdoor environments. Compared with the control specimens, the UHT specimens were able to reduce the surface temperatures of 6.2°C (day) and 1.3°C (night), after one day’s cycle of simulating indoor heat absorption and release. The outdoor measurements showed that reductions of 3.4 and 1.2°C in the surface temperature of the UHT specimens were achieved during the day and night, respectively, when compared with the temperature of the control specimens. The calculation results also indicated that more than 466 W/m2 of heat was introduced into the soil and less than 462 W/m2 of heat was transferred out of the UHT specimens, which v...

In this study, the 454 pyrosequencing technology was used to analyze the DNA of the Microcystis aeruginosa symbiosis system from cyanobacterial algal blooms in Taihu Lake, China. We generated 183 228 reads with an average length of 248 bp. Running the 454 assembly algorithm over our sequences yielded 22 239 significant contigs. After excluding the M. aeruginosa sequences, we obtained 1 322 assembled contigs longer than 1 000 bp. Taxonomic analysis indicated that four kingdoms were represented in the community: Archaea (n = 9; 0.01%), Bacteria (n = 98 921; 99.6%), Eukaryota (n = 373; 3.7%), and Viruses (n = 18; 0.02%). The bacterial sequences were predominantly Alphaproteobacteria (n = 41 805; 83.3%), Betaproteobacteria (n = 5 254; 10.5%) and Gammaproteobacteria (n = 1 180; 2.4%). Gene annotations and assignment of COG (clusters of orthologous groups) functional categories indicate that a large number of the predicted genes are involved in metabolic, genetic, and environmental information processes. Our results demonstrate the extraordinary diversity of a microbial community in an ectosymbiotic system and further establish the tremendous utility of pyrosequencing.