Laser waterless cleaning of residual organic solvents on the surface of polyurethane coatings.

Residual organic solvents have a great impact on the physical and mental health of equipment operators in industry and agriculture. Laser waterless cleaning technology of residual organic solvents on the surface of polyurethane coatings has great application prospects and is a good way to tackle the pollution problem. In this paper, the evolutionary behavior of a laser waterless cleaning mechanism and substrate surface state is analyzed. The influence law of laser energy density and scanning speed on the residual solvent cleaning effect was investigated. The optimal laser cleaning parameters were obtained by comprehensive evaluation of the substrate surface cleaning effect and microscopic morphology. The peak of solvent characteristics before and after laser cleaning was detected by Raman spectroscopy. The results demonstrated that the laser cleaning effect was better with the increase of energy density or the decrease of scanning speed in the substrate damage range, and the best laser cleaning parameters were laser energy density of 0.24J/c m 2 and scanning speed of 500 mm/s. A significant reduction of the peak of Raman spectroscopy was found, reflecting the excellent effect of laser waterless cleaning of residual organic solvents.

Detection of carbendazim in oranges with metal grating integrated microfluidic sensor in terahertz.

A novel microfluidic metal grating integrated terahertz sensor has been designed, which is composed of a metal microstructure array-dielectric layer-metal layer, where the dielectric layer is the microfluidic channel carrying the analyte. By adjusting the structural parameters of the metal grating sensor, a highly confined electromagnetic field can be obtained in the microfluidic channel, thereby significantly enhancing the interaction between the analyte and the terahertz wave and improving the terahertz detection sensitivity. The metal grating described in this paper is composed of an array of square holes, which is manufactured using laser micromachining technology, so that the measurement method is simplified and improved. The results show that the addition of different concentrations of carbendazim solution resulted in a redshift of the overall spectrum, with the highest sensitivity reaching 8.773 GHz/mg L-1, which is about eight times more sensitive than the traditional terahertz transmission sensor. The relative error of using this method to determine carbendazim levels in orange juice samples was less than 5.3%. The terahertz time-domain spectroscopy technology combined with the metal grating integrated microfluidic sensor can improve the sensitivity of sample detection and realize the rapid detection and analysis of trace elements.

[Analgesic effect of acupuncture at Neimadian(Extra) in postoperation of abdominal surgery].

OBJECTIVE: To observe the analgesia effectiveness and safety of electroacupuncture at Neimadian(Extra) for postoperation of abdominal surgery. METHODS: One hundred and twenty patients with routine abdominal surgery were randomly divided into an acupuncture group and a medication group, 60 cases in each group. The acupuncture group was treated with electroacupuncture at Neimadian(Extra), which was located on the inside of lower leg, 7 cun above the internal malleolus and 0.5 cun from post edge of tibial. The medication group was treated with patient-controlled intravenous analgesia (PCIA) with Sufentanil. After the treatment, the Visual Analogue Scale (VAS), the security, the analgesic effect and beta-endorphin content were compared. RESULTS: The postoperative VAS score at 2, 4, 8, 16, 24 and 48 h in the acupuncture group was lower than those in the medication group (all P < 0.05). The analgesic effect at 2, 4, 16 and 24 h after surgery in the acupuncture group were superior to those in the medication group (P < 0.05, P < 0.01). The beta-endorphin content at 0, 8, 16 and 48 h after surgery in both groups were increased, and the acupuncture group was superior to the medication group (all P < 0.05). The security class after surgery in the acupuncture group was higher than that in the medication group (P < 0.05). CONCLUSION: The analgesic effect and safety of electroacupuncture at Neimadian(Extra) in postoperation of abdominal surgery are superior to those of the PCIA with Sufentanil.