Background: Anesthetists should measure the concentration of supplemental oxygen to determine whether patients’ partial pressure of arterial oxygen (PaO2) is correct during general anesthesia. However, the standard P...Background: Anesthetists should measure the concentration of supplemental oxygen to determine whether patients’ partial pressure of arterial oxygen (PaO2) is correct during general anesthesia. However, the standard PaO2 value in obese patients in the supine position is unknown. We evaluated the PaO2 with respect to the Broca-Katsura obesity index. Materials and Methods: From January 2001 to December 2013, we evaluated 472 patients aged ≥16 years old that underwent general anesthesia in the supine position. The anesthetic charts of 472 patients with an American Society of Anesthesiologists physical status of I or II were retrospectively reviewed to investigate the PaO2. Results: In patients aged 16 to 2 was 165.7 ± 25.6 mmHg at a Broca-Katsura index of 2 was 152.1 ± 23.8 mmHg at a Broca-Katsura index of 2 tended to decrease with age from 16 to 2 tended to decrease with age from 16 to <65 years at a Broca-Katsura index of 20% to <40%.展开更多
A high temperature equilibration experiment was carried out to investigate the effect of oxygen partial pres- sure on the phase equilibria and liquidus in CaO-Al2O3- FeOx system with the intermediate oxygen partial pr...A high temperature equilibration experiment was carried out to investigate the effect of oxygen partial pres- sure on the phase equilibria and liquidus in CaO-Al2O3- FeOx system with the intermediate oxygen partial pressures of 10.13 Pa and 1.01 × 10^-3 Pa. The equilibrated phases and their compositions of the quenched samples were analyzed by using SEM/EPMA （Scanning Electron Microscope/Electron Probe Micro Analysis） and XRD （X Ray Diffraction）. The phase equilibrium results include two cases, the two phase coexistence and the three-phase coexistence in the high Al2O3 region with oxygen partial pressure of either 10.13 Pa or 1.01 × 10^-3 Pa. Effects of oxygen partial pressure and temperature on the liquidus along the primary phase fields of CaO · Al2O3 and CaO · 2Al2O3 were nota hle. With the decrease of oxygen partial pressure, the liquid area expands and the liquidus of CaO · Al2O3 and CaO · 2Al2O3 primary fields moves to the Al2O3-FeOx region. On the other hand, the liquid area of CaO Al2O3-FeOx sys tem extends extremely to the high Al2O3 region with the temperature increasing from 1 400 to 1 500℃, especially at lower oxygen partial pressure. The present experiment results are in good agreement with the calculated ones by FactSage.展开更多
目的分析脓毒症肺损伤患者中医证型分布状况与肺损伤相关指标及序贯性器官衰竭评分(sequential organ failure assessment,SOFA)、急性生理和慢性健康状况Ⅱ(Acute Physiology and Chronic Health EvaluationⅡ,APACHEⅡ)评分的相关性...目的分析脓毒症肺损伤患者中医证型分布状况与肺损伤相关指标及序贯性器官衰竭评分(sequential organ failure assessment,SOFA)、急性生理和慢性健康状况Ⅱ(Acute Physiology and Chronic Health EvaluationⅡ,APACHEⅡ)评分的相关性。方法选取2022年1月—2023年1月医院收治的脓毒症肺损伤患者80例,收集患者的一般资料、肺损伤相关指标[动脉血氧合指数(ratio of partial pressure of O_(2) in arterial blood to fraction of inspired oxygen,PaO_(2)/FiO_(2))、肺泡动脉氧分压差(alveolar-arterial oxygen gradient,P(A-a)O_(2))]及SOFA、APACHEⅡ评分情况,根据中医分型标准对脓毒症肺损伤患者进行分型,比较不同分型的脓毒症肺损伤患者以上各观察指标情况并分析相关性。结果脓毒症肺损伤患者以肺热壅痹证型占比最高、35.00%(28/80),其次为瘀血阻肺型27.50%(22/80),肺塞腑实型23.75%(19/80),水饮郁肺型13.75%(11/80)。不同证型的患者在性别、年龄方面差异均无统计学意义(P>0.05);不同证型的患者肺损伤指标PaO_(2)/FiO_(2)、P(A-a)O_(2)差异均有统计学意义(P<0.05);不同证型的患者SOFA、APACHEⅡ评分差异均有统计学意义(P<0.05)。肺热壅痹、瘀血阻肺、肺塞腑实、水饮郁肺证型与PaO_(2)/FiO_(2)呈显著负相关(P<0.05),与P(A-a)O_(2)、SOFA评分、APACHEⅡ评分呈显著正相关(P<0.05)。结论脓毒症肺损伤患者中医证型主要为肺热壅痹、瘀血阻肺、肺塞腑实、水饮郁肺,与肺损伤相关指标及SOFA、APACHEⅡ评分密切相关,掌握脓毒症肺损伤辨证分型特点并观察患者肺损伤相关指标及SOFA、APACHEⅡ评分变化,对疾病诊治及预后评估具有较高价值。展开更多
Objective To explore the effects of sliding-cup with different parameters on energy metabolism in the body by observing the effect of sliding-cup along the governor vessel on transcutaneous partial pressures of oxygen...Objective To explore the effects of sliding-cup with different parameters on energy metabolism in the body by observing the effect of sliding-cup along the governor vessel on transcutaneous partial pressures of oxygen and carbon dioxide in Mìngmén（命门 GV 4） in sub-healthy people. Methods A total of 10 sub-healthy adults at rest were observed and sliding-cup along the governor vessel were conducted with three different parameters, jar-pressure of –0.01~ –0.02 MPa with sliding-cup for 5 min, jar-pressure of –0.02~ –0.03 MPa with sliding-cup for 5 min and jar-pressure of –0.02~ –0.03 MPa with slidingcup for 3 min. Peri Flux System5000 PF5040 module was employed to monitor the changes of transcutaneous partial pressures of oxygen（tcp O2） and carbon dioxide（tcp CO2） in GV 4 at 0 min, 5 min, 10 min, 15 min, 20 min, 25 min and 30 min after sliding-cup with above different interventions in sub-healthy subjects. Results After sliding-cup, tcp O2 increased at first and then decreased over time; there was no difference in tcp O2 after sliding-cupping with different parameters（all P0.05）. After sliding-cup, tcp CO2 decreased; there was no difference in tcp CO2 after sliding-cup with different parameters（all P0.05）. Conclusion Sliding-cup has a sustained effect on the body and can speed up the energy metabolism in the body.展开更多
Objective:To explore the easily applicable indicators of practical value to evaluate the prognosis of acute respiratory distress syndrome（ARDS）.Methods:Blood and biochemical tests and bloodgas analyses were performe...Objective:To explore the easily applicable indicators of practical value to evaluate the prognosis of acute respiratory distress syndrome（ARDS）.Methods:Blood and biochemical tests and bloodgas analyses were performed upon entry into the ICUs,12 h,24 h,48 h and 72 h after that in 72 ARDS patients（who were admitted to the ICUs of our hospital from January 2000 to December 2009）.Then APACHEⅡscores were achieved by combining relevant physiological parameters and laboratory results.Results:There was a statistical difference between the death group and survival group at different time points upon entering the ICUs in terms of APACHEⅡscore, alveolar-arterial oxygen difference and arterial blood lactate clearance rate.PaO<sub>2</sub>/FiO<sub>2</sub> values were recorded to be statistically different between the death group and survival group 24 h,48 h and 72 h,respectively after entry into the ICUs.In addition,registered linear regression existed between APACHEⅡscore,alveolar-arterial oxygen difference or PaO<sub>2</sub>/FiO<sub>2</sub> value and time. APACHEⅡscore 24 h and 72 h after entering ICUs predicted mortality with an area under the ROC curve（AUC） standing respectively at 0.919 and 0.9SS.Arterial blood lactate clearance rate 12 h, 24 h,48 h and 72 h after entering ICUs predicted mortality with an area under the ROC curve （AUC） at 0.918,0.918,0.909 and 0.991,respectively.Conclusions:APACHEⅡscore applied in combination with arterial blood lactate clearance rate is of clinical significance in assessing the prognosis of ARDS patients.展开更多
High-temperature experiments were carried out for the slag systems of“FeO”−SiO_(2)−CaO−Al_(2)O_(3)and“FeO”−SiO_(2)−CaO−MgO at 1200℃and p(O_(2))of 10^(−7)kPa.The equilibrated samples were quenched,and the phase co...High-temperature experiments were carried out for the slag systems of“FeO”−SiO_(2)−CaO−Al_(2)O_(3)and“FeO”−SiO_(2)−CaO−MgO at 1200℃and p(O_(2))of 10^(−7)kPa.The equilibrated samples were quenched,and the phase compositions were measured by electron probe microanalysis(EPMA).A series of pseudo-ternary and pseudo-binary phase diagrams are constructed to demonstrate their applications in copper smelting process and evaluation of the thermodynamic database.Spinel and tridymite are identified to be the major primary phases in the composition range related to the copper smelting slags.It is found that the operating window of the smelting slag is primarily determined by w_(Fe)/w_(SiO_(2))ratio in the slag.Both MgO and Al_(2)O_(3)in the slag reduce the operating window which requires extra fluxing agent to keep the slag to be fully liquid.Complex spinel solid solutions cause inaccurate predictions of the current thermodynamic database.展开更多
A SiC/ZrSiO4？SiO2 （SZS） coating was successfully fabricated on the carbon/carbon （C/C） composites by pack cementation, slurry painting and sintering to improve the anti-oxidation property and thermal shock r...A SiC/ZrSiO4？SiO2 （SZS） coating was successfully fabricated on the carbon/carbon （C/C） composites by pack cementation, slurry painting and sintering to improve the anti-oxidation property and thermal shock resistance. The anti-oxidation properties under different oxygen partial pressures （OPP） and thermal shock resistance of the SZS coating were investigated. The results show that the SZS coated sample under low OPP, corresponding to the ambient air, during isothermal oxidation was 0.54% in mass gain after 111 h oxidation at 1500 ° C and less than 0.03% in mass loss after 50 h oxidation in high OPP, corresponding to the air flow rate of 36 L/h. Additionally, the residual compressive strengths （RCS） of the SZS coated samples after oxidation for 50 h in high OPP and 80 h in low OPP remain about 70% and 72.5% of those of original C/C samples, respectively. Moreover, the mass loss of SZS coated samples subjected to the thermal cycle from 1500 ° C in high OPP to boiling water for 30 times was merely 1.61%.展开更多
Ti_(2)AlC,a MAX phase ceramic,has an attractive self-healing ability to restore performance via the oxidation-induced crack healing mechanism upon healing at high temperatures in air(high oxygen partial pressures).How...Ti_(2)AlC,a MAX phase ceramic,has an attractive self-healing ability to restore performance via the oxidation-induced crack healing mechanism upon healing at high temperatures in air(high oxygen partial pressures).However,such healing ability to repair damages in vacuum or low oxygen partial pressure conditions remains unknown.Here,we report on the self-healing behavior of Ti_(2)AlC at a low oxygen partial pressure of about 1 Pa.The experimental results showed that the strength recovery depends on both healing temperature and time.After healing at 1400℃for 1–4 h,the healed samples exhibited the recovered strengths even exceeding the original strength of 375 MPa.The maximum recovered strength of~422 MPa was achieved in the healed Ti_(2)AlC sample after healing at 1400 for 4 h,about 13%higher than the original strength.Damages were healed by the formed℃TiCx from the decomposition of Ti_(2)AlC.The decomposition-induced crack healing as a new mechanism in the low oxygen partial pressure condition was disclosed for the MAX ceramics.The present study illustrates that key components made of Ti_(2)AlC can prolong their service life and keep their reliability during use at high temperatures in low oxygen partial pressures.展开更多
Thermodynamic assessment in the ternary systems ZrO2 -CeO2 -Y2 O3, ZrO2 -CeO2 -Ce2 03 and the limiting binaries ZrO2 -Y2 O3, ZrO2 -CeO2, CeO2 -Y2 03, ZrO2 -Ce2O3, CeO2 -Ce2O3 as well as the modeling for oxides are rev...Thermodynamic assessment in the ternary systems ZrO2 -CeO2 -Y2 O3, ZrO2 -CeO2 -Ce2 03 and the limiting binaries ZrO2 -Y2 O3, ZrO2 -CeO2, CeO2 -Y2 03, ZrO2 -Ce2O3, CeO2 -Ce2O3 as well as the modeling for oxides are reviewed comprehensively. Based on the recent estimations on the YO1.5-CeO2, ZrO2-CeO2 and ZrO2 -YO1.6 systems, isothermal sections at 1273 and 1 973 K of the ternary CeO2- ZrO2-YO1.5system are calculated. In the system of ZrO2-CeO2-Ce2O3, the complex relation between the nonstoichiometry （y） in CeO2-x, the composition of the ZrO2 -CeO2 solid solution and the oxygen partial pressure （Po2 ） for different ZrO2 containing solid solutions CexZr1-xO2-x. are evaluated from 1 473 to 1 773 K. The relation between the degree of Ce^＋4 reduction to Ce.3 under different Po2 in the fluorite CeO2-xy and CexZr1-xOz-x solid solutions at different temperatures can be used as a guide in the development of functional ceramics.展开更多
For an analysis of the oxidation behavior of UO2 nuclear fuel pellet under a loss of water coolant accident in a spent nuclear fuel pool of an LWR, thermodynamic assessments of UO2 oxidation were carried out under var...For an analysis of the oxidation behavior of UO2 nuclear fuel pellet under a loss of water coolant accident in a spent nuclear fuel pool of an LWR, thermodynamic assessments of UO2 oxidation were carried out under various atmospheric conditions. In a steam atmosphere, it was assessed that UO2 would not be fully oxidized into U3O8 due to the relatively lower oxygen partial pressure, while UO2 will be fully oxidized into U3O8 in an air atmosphere. In an air and steam mixture atmosphere, the UO2 oxidation was dominantly affected by the air volumetric fraction, because of the relatively higher oxygen partial pressure of air. In addition, the effect of H2 volumetric fraction on the oxygen partial pressure under a mixture atmosphere was calculated, and it was revealed that UO2 pellet oxidation could be reduced above the critical value of H2 volumetric fraction.展开更多
Objective: to analyze the effect of optimizing emergency nursing process on the rescue of patients with chest pain. Methods: a total of 62 patients with emergency chest pain admitted to our hospital from July 2020 to ...Objective: to analyze the effect of optimizing emergency nursing process on the rescue of patients with chest pain. Methods: a total of 62 patients with emergency chest pain admitted to our hospital from July 2020 to June 2021 were randomly selected. They were divided into the control group (even number of beds) with emergency nursing and the observation group (odd number of beds) with optimized emergency nursing process. There were 31 patients in each group, and the effects after the intervention were compared. Results: after the intervention, the time spent in the rescue process of the patients in the observation group was lower than that of the control group (P < 0.05), and the hospitalization time was lower than that of the control group (P < 0.05). Meanwhile, the incidence of adverse events was also lower than that of the control group (P < 0.05), and the PaCO2 level of the patients in the observation group was significantly lower than that of the control group (P < 0.05);The PaO2 level in the observation group was higher than that in the control group (P < 0.05);The quality of life score was higher than that of the control group (P < 0.05);The satisfaction was higher than that of the control group (P < 0.05);The rescue success was also higher than that of the control group (P < 0.05). Conclusion: for emergency chest pain patients, the application of optimized emergency nursing process has a significant effect in improving the rescue success rate, reducing the incidence of adverse events, reducing the length of hospital stay, and improving the quality of life.展开更多
文摘Background: Anesthetists should measure the concentration of supplemental oxygen to determine whether patients’ partial pressure of arterial oxygen (PaO2) is correct during general anesthesia. However, the standard PaO2 value in obese patients in the supine position is unknown. We evaluated the PaO2 with respect to the Broca-Katsura obesity index. Materials and Methods: From January 2001 to December 2013, we evaluated 472 patients aged ≥16 years old that underwent general anesthesia in the supine position. The anesthetic charts of 472 patients with an American Society of Anesthesiologists physical status of I or II were retrospectively reviewed to investigate the PaO2. Results: In patients aged 16 to 2 was 165.7 ± 25.6 mmHg at a Broca-Katsura index of 2 was 152.1 ± 23.8 mmHg at a Broca-Katsura index of 2 tended to decrease with age from 16 to 2 tended to decrease with age from 16 to <65 years at a Broca-Katsura index of 20% to <40%.
基金Item Sponsored by National Natural Science Foundation of China(50974034,51074039)
文摘A high temperature equilibration experiment was carried out to investigate the effect of oxygen partial pres- sure on the phase equilibria and liquidus in CaO-Al2O3- FeOx system with the intermediate oxygen partial pressures of 10.13 Pa and 1.01 × 10^-3 Pa. The equilibrated phases and their compositions of the quenched samples were analyzed by using SEM/EPMA （Scanning Electron Microscope/Electron Probe Micro Analysis） and XRD （X Ray Diffraction）. The phase equilibrium results include two cases, the two phase coexistence and the three-phase coexistence in the high Al2O3 region with oxygen partial pressure of either 10.13 Pa or 1.01 × 10^-3 Pa. Effects of oxygen partial pressure and temperature on the liquidus along the primary phase fields of CaO · Al2O3 and CaO · 2Al2O3 were nota hle. With the decrease of oxygen partial pressure, the liquid area expands and the liquidus of CaO · Al2O3 and CaO · 2Al2O3 primary fields moves to the Al2O3-FeOx region. On the other hand, the liquid area of CaO Al2O3-FeOx sys tem extends extremely to the high Al2O3 region with the temperature increasing from 1 400 to 1 500℃, especially at lower oxygen partial pressure. The present experiment results are in good agreement with the calculated ones by FactSage.
文摘目的分析脓毒症肺损伤患者中医证型分布状况与肺损伤相关指标及序贯性器官衰竭评分(sequential organ failure assessment,SOFA)、急性生理和慢性健康状况Ⅱ(Acute Physiology and Chronic Health EvaluationⅡ,APACHEⅡ)评分的相关性。方法选取2022年1月—2023年1月医院收治的脓毒症肺损伤患者80例,收集患者的一般资料、肺损伤相关指标[动脉血氧合指数(ratio of partial pressure of O_(2) in arterial blood to fraction of inspired oxygen,PaO_(2)/FiO_(2))、肺泡动脉氧分压差(alveolar-arterial oxygen gradient,P(A-a)O_(2))]及SOFA、APACHEⅡ评分情况,根据中医分型标准对脓毒症肺损伤患者进行分型,比较不同分型的脓毒症肺损伤患者以上各观察指标情况并分析相关性。结果脓毒症肺损伤患者以肺热壅痹证型占比最高、35.00%(28/80),其次为瘀血阻肺型27.50%(22/80),肺塞腑实型23.75%(19/80),水饮郁肺型13.75%(11/80)。不同证型的患者在性别、年龄方面差异均无统计学意义(P>0.05);不同证型的患者肺损伤指标PaO_(2)/FiO_(2)、P(A-a)O_(2)差异均有统计学意义(P<0.05);不同证型的患者SOFA、APACHEⅡ评分差异均有统计学意义(P<0.05)。肺热壅痹、瘀血阻肺、肺塞腑实、水饮郁肺证型与PaO_(2)/FiO_(2)呈显著负相关(P<0.05),与P(A-a)O_(2)、SOFA评分、APACHEⅡ评分呈显著正相关(P<0.05)。结论脓毒症肺损伤患者中医证型主要为肺热壅痹、瘀血阻肺、肺塞腑实、水饮郁肺,与肺损伤相关指标及SOFA、APACHEⅡ评分密切相关,掌握脓毒症肺损伤辨证分型特点并观察患者肺损伤相关指标及SOFA、APACHEⅡ评分变化,对疾病诊治及预后评估具有较高价值。
基金Suported by Tianjin Municipal Administration of Traditional Chinese Medicine:11028
文摘Objective To explore the effects of sliding-cup with different parameters on energy metabolism in the body by observing the effect of sliding-cup along the governor vessel on transcutaneous partial pressures of oxygen and carbon dioxide in Mìngmén（命门 GV 4） in sub-healthy people. Methods A total of 10 sub-healthy adults at rest were observed and sliding-cup along the governor vessel were conducted with three different parameters, jar-pressure of –0.01~ –0.02 MPa with sliding-cup for 5 min, jar-pressure of –0.02~ –0.03 MPa with sliding-cup for 5 min and jar-pressure of –0.02~ –0.03 MPa with slidingcup for 3 min. Peri Flux System5000 PF5040 module was employed to monitor the changes of transcutaneous partial pressures of oxygen（tcp O2） and carbon dioxide（tcp CO2） in GV 4 at 0 min, 5 min, 10 min, 15 min, 20 min, 25 min and 30 min after sliding-cup with above different interventions in sub-healthy subjects. Results After sliding-cup, tcp O2 increased at first and then decreased over time; there was no difference in tcp O2 after sliding-cupping with different parameters（all P0.05）. After sliding-cup, tcp CO2 decreased; there was no difference in tcp CO2 after sliding-cup with different parameters（all P0.05）. Conclusion Sliding-cup has a sustained effect on the body and can speed up the energy metabolism in the body.
基金sponsored by Guangdong Science and Technology Project(No:2009B03081118)
文摘Objective:To explore the easily applicable indicators of practical value to evaluate the prognosis of acute respiratory distress syndrome（ARDS）.Methods:Blood and biochemical tests and bloodgas analyses were performed upon entry into the ICUs,12 h,24 h,48 h and 72 h after that in 72 ARDS patients（who were admitted to the ICUs of our hospital from January 2000 to December 2009）.Then APACHEⅡscores were achieved by combining relevant physiological parameters and laboratory results.Results:There was a statistical difference between the death group and survival group at different time points upon entering the ICUs in terms of APACHEⅡscore, alveolar-arterial oxygen difference and arterial blood lactate clearance rate.PaO<sub>2</sub>/FiO<sub>2</sub> values were recorded to be statistically different between the death group and survival group 24 h,48 h and 72 h,respectively after entry into the ICUs.In addition,registered linear regression existed between APACHEⅡscore,alveolar-arterial oxygen difference or PaO<sub>2</sub>/FiO<sub>2</sub> value and time. APACHEⅡscore 24 h and 72 h after entering ICUs predicted mortality with an area under the ROC curve（AUC） standing respectively at 0.919 and 0.9SS.Arterial blood lactate clearance rate 12 h, 24 h,48 h and 72 h after entering ICUs predicted mortality with an area under the ROC curve （AUC） at 0.918,0.918,0.909 and 0.991,respectively.Conclusions:APACHEⅡscore applied in combination with arterial blood lactate clearance rate is of clinical significance in assessing the prognosis of ARDS patients.
文摘High-temperature experiments were carried out for the slag systems of“FeO”−SiO_(2)−CaO−Al_(2)O_(3)and“FeO”−SiO_(2)−CaO−MgO at 1200℃and p(O_(2))of 10^(−7)kPa.The equilibrated samples were quenched,and the phase compositions were measured by electron probe microanalysis(EPMA).A series of pseudo-ternary and pseudo-binary phase diagrams are constructed to demonstrate their applications in copper smelting process and evaluation of the thermodynamic database.Spinel and tridymite are identified to be the major primary phases in the composition range related to the copper smelting slags.It is found that the operating window of the smelting slag is primarily determined by w_(Fe)/w_(SiO_(2))ratio in the slag.Both MgO and Al_(2)O_(3)in the slag reduce the operating window which requires extra fluxing agent to keep the slag to be fully liquid.Complex spinel solid solutions cause inaccurate predictions of the current thermodynamic database.
基金Project supported by the Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center,ChinaProject(51205417)supported by the National Natural Science Foundation of China
文摘A SiC/ZrSiO4？SiO2 （SZS） coating was successfully fabricated on the carbon/carbon （C/C） composites by pack cementation, slurry painting and sintering to improve the anti-oxidation property and thermal shock resistance. The anti-oxidation properties under different oxygen partial pressures （OPP） and thermal shock resistance of the SZS coating were investigated. The results show that the SZS coated sample under low OPP, corresponding to the ambient air, during isothermal oxidation was 0.54% in mass gain after 111 h oxidation at 1500 ° C and less than 0.03% in mass loss after 50 h oxidation in high OPP, corresponding to the air flow rate of 36 L/h. Additionally, the residual compressive strengths （RCS） of the SZS coated samples after oxidation for 50 h in high OPP and 80 h in low OPP remain about 70% and 72.5% of those of original C/C samples, respectively. Moreover, the mass loss of SZS coated samples subjected to the thermal cycle from 1500 ° C in high OPP to boiling water for 30 times was merely 1.61%.
基金supported by the National Natural Science Foundation of China(No.52275171)the PreResearch Program in National 14th Five-Year Plan(No.80923010304).
文摘Ti_(2)AlC,a MAX phase ceramic,has an attractive self-healing ability to restore performance via the oxidation-induced crack healing mechanism upon healing at high temperatures in air(high oxygen partial pressures).However,such healing ability to repair damages in vacuum or low oxygen partial pressure conditions remains unknown.Here,we report on the self-healing behavior of Ti_(2)AlC at a low oxygen partial pressure of about 1 Pa.The experimental results showed that the strength recovery depends on both healing temperature and time.After healing at 1400℃for 1–4 h,the healed samples exhibited the recovered strengths even exceeding the original strength of 375 MPa.The maximum recovered strength of~422 MPa was achieved in the healed Ti_(2)AlC sample after healing at 1400 for 4 h,about 13%higher than the original strength.Damages were healed by the formed℃TiCx from the decomposition of Ti_(2)AlC.The decomposition-induced crack healing as a new mechanism in the low oxygen partial pressure condition was disclosed for the MAX ceramics.The present study illustrates that key components made of Ti_(2)AlC can prolong their service life and keep their reliability during use at high temperatures in low oxygen partial pressures.
文摘Thermodynamic assessment in the ternary systems ZrO2 -CeO2 -Y2 O3, ZrO2 -CeO2 -Ce2 03 and the limiting binaries ZrO2 -Y2 O3, ZrO2 -CeO2, CeO2 -Y2 03, ZrO2 -Ce2O3, CeO2 -Ce2O3 as well as the modeling for oxides are reviewed comprehensively. Based on the recent estimations on the YO1.5-CeO2, ZrO2-CeO2 and ZrO2 -YO1.6 systems, isothermal sections at 1273 and 1 973 K of the ternary CeO2- ZrO2-YO1.5system are calculated. In the system of ZrO2-CeO2-Ce2O3, the complex relation between the nonstoichiometry （y） in CeO2-x, the composition of the ZrO2 -CeO2 solid solution and the oxygen partial pressure （Po2 ） for different ZrO2 containing solid solutions CexZr1-xO2-x. are evaluated from 1 473 to 1 773 K. The relation between the degree of Ce^＋4 reduction to Ce.3 under different Po2 in the fluorite CeO2-xy and CexZr1-xOz-x solid solutions at different temperatures can be used as a guide in the development of functional ceramics.
文摘For an analysis of the oxidation behavior of UO2 nuclear fuel pellet under a loss of water coolant accident in a spent nuclear fuel pool of an LWR, thermodynamic assessments of UO2 oxidation were carried out under various atmospheric conditions. In a steam atmosphere, it was assessed that UO2 would not be fully oxidized into U3O8 due to the relatively lower oxygen partial pressure, while UO2 will be fully oxidized into U3O8 in an air atmosphere. In an air and steam mixture atmosphere, the UO2 oxidation was dominantly affected by the air volumetric fraction, because of the relatively higher oxygen partial pressure of air. In addition, the effect of H2 volumetric fraction on the oxygen partial pressure under a mixture atmosphere was calculated, and it was revealed that UO2 pellet oxidation could be reduced above the critical value of H2 volumetric fraction.
文摘Objective: to analyze the effect of optimizing emergency nursing process on the rescue of patients with chest pain. Methods: a total of 62 patients with emergency chest pain admitted to our hospital from July 2020 to June 2021 were randomly selected. They were divided into the control group (even number of beds) with emergency nursing and the observation group (odd number of beds) with optimized emergency nursing process. There were 31 patients in each group, and the effects after the intervention were compared. Results: after the intervention, the time spent in the rescue process of the patients in the observation group was lower than that of the control group (P < 0.05), and the hospitalization time was lower than that of the control group (P < 0.05). Meanwhile, the incidence of adverse events was also lower than that of the control group (P < 0.05), and the PaCO2 level of the patients in the observation group was significantly lower than that of the control group (P < 0.05);The PaO2 level in the observation group was higher than that in the control group (P < 0.05);The quality of life score was higher than that of the control group (P < 0.05);The satisfaction was higher than that of the control group (P < 0.05);The rescue success was also higher than that of the control group (P < 0.05). Conclusion: for emergency chest pain patients, the application of optimized emergency nursing process has a significant effect in improving the rescue success rate, reducing the incidence of adverse events, reducing the length of hospital stay, and improving the quality of life.
