Objective: To compare the clinical effects of uterine cavity observation and suction surgery system with ultrasound guided induced abortion in very early pregnancy induced abortion surgery. Method: Select 80 patients ...Objective: To compare the clinical effects of uterine cavity observation and suction surgery system with ultrasound guided induced abortion in very early pregnancy induced abortion surgery. Method: Select 80 patients who requested termination of pregnancy due to early pregnancy from August 2022 to April 2023, and analyze the data. 40 patients who underwent ultrasound-guided induced abortion to terminate pregnancy were included in the control group, and 40 patients who underwent uterine cavity observation surgery to terminate pregnancy were included in the observation group. Compare the surgical time, number of times the straw enters the uterine cavity, incidence of complications, and menstrual recovery time between the two groups. Results: There was no statistically significant difference in the surgical time between the observation group and the control group, but the number of times negative pressure straws entered the uterine cavity and the incidence of surgical complications in the observation group were significantly lower than those in the control group (P Conclusion: Applying the uterine cavity observation and suction surgical system to terminate pregnancy in very early pregnancy has the advantages of minimal damage to the uterus and low incidence of surgical complications, greatly protecting the patient’s fertility.展开更多
A radiative heat transfer mathematical model for a one-dimensional long furnace was set up in a through-type roller-hearth furnace (TTRHF) in compact strip production (CSP). To accurately predict the heat exchange...A radiative heat transfer mathematical model for a one-dimensional long furnace was set up in a through-type roller-hearth furnace (TTRHF) in compact strip production (CSP). To accurately predict the heat exchange in the furnace, modeling of the complex gas energy-balance equation in volume zones was considered, and the heat transfer model of heating slabs and wall lines was coupled with the radiative heat transfer model to identify the surface zonal temperature. With numerical simulation, the temperature fields of gas, slabs, and wall lines in the furnace under one typical working condition were carefully accounted and analyzed. The fundamental theory for analyzing the thermal process in TI'RI-IF was provided.展开更多
A new hybrid method, Monte-Carlo-Heat-Flux (MCHF) method, was presented to analyze the radiative heat transfer of participating medium in a three-dimensional rectangular enclosure using combined the Monte-Carlo meth...A new hybrid method, Monte-Carlo-Heat-Flux (MCHF) method, was presented to analyze the radiative heat transfer of participating medium in a three-dimensional rectangular enclosure using combined the Monte-Carlo method with the heat flux method. Its accuracy and reliability was proved by comparing the computational results with exact results from classical "Zone Method".展开更多
In accordance with the cerium-lanthanum ratio of fluorocerium ores in the mineralogy of the Baiyun Ebo process, the (Ce,La)CO<sub>3</sub>F grains were synthesised by hydrothermal method using pure material...In accordance with the cerium-lanthanum ratio of fluorocerium ores in the mineralogy of the Baiyun Ebo process, the (Ce,La)CO<sub>3</sub>F grains were synthesised by hydrothermal method using pure material to simulate bastnaesite minerals, and used as NH<sub>3</sub>-SCR denitrification catalysts. The activity results showed that the synthetic (Ce,La)CO<sub>3</sub>F was roasted at 500<span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">, and the NOx conversion was 27% at 200</span></span></span><span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">. The NH<sub>3</sub></span></span></span><span><span><span style="font-family:;" "="">-</span></span></span><span><span><span style="font-family:;" "="">SCR catalytic activity of the synthesised (Ce,La)CO<sub>3</sub>F was improved by loaded transition metal Mn. The best catalyst was found to be produced by impregnating (Ce,La)CO<sub>3</sub>F with 1 mol/L manganese nitrate solution, with a NOx conversion of 80% at 250</span></span></span><span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">. The loading of Mn resulted in the appearance of numerous well-dispersed MnOx species on the catalyst surface, the dispersion of Ce<sub>7</sub>O<sub>12</sub> species was also greatly enhanced, and the reduction in grain size indicated that Mn<sup>n+</sup> entered into the (Ce,La)CO<sub>3</sub>F lattice causing lattice shrinkage. The number of acidic sites on the catalyst surface and the redox capacity were enhanced. The amount of Ce<sup>3+</sup> in the catalyst was also enhanced by the introduction of Mn<sup>n+</sup>, but the proportion of adsorbed oxygen decreased, which indicated that the introduction of Mn<sup>n+</sup> was detrimental to the increase in the proportion of adsorbed oxygen. The reaction mechanisms of the (Ce,La)CO<sub>3</sub>F and Mn/(Ce,La)CO<sub>3</sub>F catalysts were investigated by <i>in-situ</i> Fourier transform infrared spectroscopy (FTIR). The results showed that catalysts followed the E-R and L-H mechanisms. When loaded with Mn, the main reactive species in the L-H mechanism were the </span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species on the Br<span style="white-space:nowrap;">ø</span>nsted acidic site and the O-Ce<sup>3+</sup>-O-NO, O-Mn<sup>3+</sup>-O-NO species. The main reactive species for the E-R mechanism were NH<sub>3</sub>/</span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species and NO. The </span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species on the Br<span style="white-space:nowrap;">ø</span>nsted acidic sites act as the main reactive NH3</span></span></span><span><span><sub><span style="font-family:;" "=""> </span></sub></span></span><span><span><span style="font-family:;" "="">(g) adsorbing species, bonded to the Ce<sup>4+</sup> in the carrier (Ce,La)CO<sub>3</sub>F to participate in the acid cycle reaction. The introduction of Mn<sup>n+</sup> increases the number of Br<span style="white-space:nowrap;">ø</span>nsted acidic sites on the catalyst surface, and acts as an adsorption site for NO, to react with NO to generate more monodentate nitrate species, to participate in the redox cycle reactions. The above results indicated that Mn<sup>n+</sup> and (Ce,La)CO<sub>3</sub>F have a good mutual promotion effect, which makes the loaded catalyst have excellent performance, which provides a theoretical basis for the high value utilization of bastnaesite</span></span></span><span><span><span style="font-family:;" "="">.</span></span></span>展开更多
Temperature uniformity of steel coils in High Performance Hydrogen bell-type annealing furnace has a significant effect on their quality and production. The hot rolled coil can be considered as a periodically laminate...Temperature uniformity of steel coils in High Performance Hydrogen bell-type annealing furnace has a significant effect on their quality and production. The hot rolled coil can be considered as a periodically laminated material composed of steel layers and interface layers in radial direction. A new formula for the radial effective thermal conductivity has been proposed, which is based on surface characteristic, strip thickness and compressive stress of the rolled coil. Furthermore, it has been used to develop a heat transfer mathematical model for steel coils in the HPH furnace. The calculated annealing curves using this mathematical model are in good agreement with the experimental data.展开更多
文摘Objective: To compare the clinical effects of uterine cavity observation and suction surgery system with ultrasound guided induced abortion in very early pregnancy induced abortion surgery. Method: Select 80 patients who requested termination of pregnancy due to early pregnancy from August 2022 to April 2023, and analyze the data. 40 patients who underwent ultrasound-guided induced abortion to terminate pregnancy were included in the control group, and 40 patients who underwent uterine cavity observation surgery to terminate pregnancy were included in the observation group. Compare the surgical time, number of times the straw enters the uterine cavity, incidence of complications, and menstrual recovery time between the two groups. Results: There was no statistically significant difference in the surgical time between the observation group and the control group, but the number of times negative pressure straws entered the uterine cavity and the incidence of surgical complications in the observation group were significantly lower than those in the control group (P Conclusion: Applying the uterine cavity observation and suction surgical system to terminate pregnancy in very early pregnancy has the advantages of minimal damage to the uterus and low incidence of surgical complications, greatly protecting the patient’s fertility.
文摘A radiative heat transfer mathematical model for a one-dimensional long furnace was set up in a through-type roller-hearth furnace (TTRHF) in compact strip production (CSP). To accurately predict the heat exchange in the furnace, modeling of the complex gas energy-balance equation in volume zones was considered, and the heat transfer model of heating slabs and wall lines was coupled with the radiative heat transfer model to identify the surface zonal temperature. With numerical simulation, the temperature fields of gas, slabs, and wall lines in the furnace under one typical working condition were carefully accounted and analyzed. The fundamental theory for analyzing the thermal process in TI'RI-IF was provided.
基金financially supported by the National Natural Science Foundation of China (No.50464004)
文摘A new hybrid method, Monte-Carlo-Heat-Flux (MCHF) method, was presented to analyze the radiative heat transfer of participating medium in a three-dimensional rectangular enclosure using combined the Monte-Carlo method with the heat flux method. Its accuracy and reliability was proved by comparing the computational results with exact results from classical "Zone Method".
文摘In accordance with the cerium-lanthanum ratio of fluorocerium ores in the mineralogy of the Baiyun Ebo process, the (Ce,La)CO<sub>3</sub>F grains were synthesised by hydrothermal method using pure material to simulate bastnaesite minerals, and used as NH<sub>3</sub>-SCR denitrification catalysts. The activity results showed that the synthetic (Ce,La)CO<sub>3</sub>F was roasted at 500<span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">, and the NOx conversion was 27% at 200</span></span></span><span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">. The NH<sub>3</sub></span></span></span><span><span><span style="font-family:;" "="">-</span></span></span><span><span><span style="font-family:;" "="">SCR catalytic activity of the synthesised (Ce,La)CO<sub>3</sub>F was improved by loaded transition metal Mn. The best catalyst was found to be produced by impregnating (Ce,La)CO<sub>3</sub>F with 1 mol/L manganese nitrate solution, with a NOx conversion of 80% at 250</span></span></span><span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">. The loading of Mn resulted in the appearance of numerous well-dispersed MnOx species on the catalyst surface, the dispersion of Ce<sub>7</sub>O<sub>12</sub> species was also greatly enhanced, and the reduction in grain size indicated that Mn<sup>n+</sup> entered into the (Ce,La)CO<sub>3</sub>F lattice causing lattice shrinkage. The number of acidic sites on the catalyst surface and the redox capacity were enhanced. The amount of Ce<sup>3+</sup> in the catalyst was also enhanced by the introduction of Mn<sup>n+</sup>, but the proportion of adsorbed oxygen decreased, which indicated that the introduction of Mn<sup>n+</sup> was detrimental to the increase in the proportion of adsorbed oxygen. The reaction mechanisms of the (Ce,La)CO<sub>3</sub>F and Mn/(Ce,La)CO<sub>3</sub>F catalysts were investigated by <i>in-situ</i> Fourier transform infrared spectroscopy (FTIR). The results showed that catalysts followed the E-R and L-H mechanisms. When loaded with Mn, the main reactive species in the L-H mechanism were the </span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species on the Br<span style="white-space:nowrap;">ø</span>nsted acidic site and the O-Ce<sup>3+</sup>-O-NO, O-Mn<sup>3+</sup>-O-NO species. The main reactive species for the E-R mechanism were NH<sub>3</sub>/</span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species and NO. The </span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species on the Br<span style="white-space:nowrap;">ø</span>nsted acidic sites act as the main reactive NH3</span></span></span><span><span><sub><span style="font-family:;" "=""> </span></sub></span></span><span><span><span style="font-family:;" "="">(g) adsorbing species, bonded to the Ce<sup>4+</sup> in the carrier (Ce,La)CO<sub>3</sub>F to participate in the acid cycle reaction. The introduction of Mn<sup>n+</sup> increases the number of Br<span style="white-space:nowrap;">ø</span>nsted acidic sites on the catalyst surface, and acts as an adsorption site for NO, to react with NO to generate more monodentate nitrate species, to participate in the redox cycle reactions. The above results indicated that Mn<sup>n+</sup> and (Ce,La)CO<sub>3</sub>F have a good mutual promotion effect, which makes the loaded catalyst have excellent performance, which provides a theoretical basis for the high value utilization of bastnaesite</span></span></span><span><span><span style="font-family:;" "="">.</span></span></span>
基金This work has been supported by Cross-Century Talents Projects of Educational Ministry of China.
文摘Temperature uniformity of steel coils in High Performance Hydrogen bell-type annealing furnace has a significant effect on their quality and production. The hot rolled coil can be considered as a periodically laminated material composed of steel layers and interface layers in radial direction. A new formula for the radial effective thermal conductivity has been proposed, which is based on surface characteristic, strip thickness and compressive stress of the rolled coil. Furthermore, it has been used to develop a heat transfer mathematical model for steel coils in the HPH furnace. The calculated annealing curves using this mathematical model are in good agreement with the experimental data.