A principle was proposed for designing a method to seal anodized aluminum used in semiconductor processing apparatuses.Thermodynamic calculations and Fick’s second law were used to reveal trends in the metal ion depo...A principle was proposed for designing a method to seal anodized aluminum used in semiconductor processing apparatuses.Thermodynamic calculations and Fick’s second law were used to reveal trends in the metal ion deposition,deposition product stability,vapor pressures of halides for selected metal ions,the holding temperature,and time.Interactions between ion concentrations and the sealing temperature were also revealed.According to the design principles,anodized aluminum dipped in 1 mM Cr^(3+)ion solution and steam-sealed for 18 h exhibited the highest corrosion resistance when exposed to 5 wt.%HCl solution and HCl gas,verifying the designed results.展开更多
Many variables affect the sealing performance, and their distribution characteristics are difficult to obtain with probabilistic methods owing to the high cost involved. Numerous problems in engineering are similar du...Many variables affect the sealing performance, and their distribution characteristics are difficult to obtain with probabilistic methods owing to the high cost involved. Numerous problems in engineering are similar due to the appearance of small-sample parameters. In this study, the sealing reliability of an aviation seal was defined as the research object, and an interval uncertainty method and multidimensional response surface were proposed to calculate the sealing reliability.Based on this, we first analyzed the failure mechanism of the aviation seal and established a leakage rate model. Then, based on the non-probabilistic interval model, an interval uncertainty method was proposed to construct the analytical model. With reference to the limit state equation from the structural reliability theory, the multidimensional response surface was used for fast calculation.Then, we chose the single-cylinder gas steering gear used in aircraft as the case study, its sealing reliability in working and non-working statuses were calculated, and the results were verified with the actual maintenance records. By analyzing the sensitivity of some variables, we can improve the sealing reliability of the aviation seal by improving the surface roughness only if the cost allows.Finally, we consider that the method proposed in this study realizes the application of smallsample uncertainty analysis in reliability analysis, and could provide a feasible way to solve the similar problems in engineering with multidimensional and small-sample parameters.展开更多
Dear Editor,In a recent interventional case report,Allon et al ）hydrated corneal stroma with cefuroxime to seal a small traumatic leaky corneal perforation that was unresponsive to prior soft bandage contact lens app...Dear Editor,In a recent interventional case report,Allon et al ）hydrated corneal stroma with cefuroxime to seal a small traumatic leaky corneal perforation that was unresponsive to prior soft bandage contact lens application for 6d.展开更多
Fuzzy mathematics is an important means to quantitatively evaluate the properties of fault sealing in petroleum reservoirs.To accurately study fault sealing,the comprehensive quantitative evaluation method of fuzzy ma...Fuzzy mathematics is an important means to quantitatively evaluate the properties of fault sealing in petroleum reservoirs.To accurately study fault sealing,the comprehensive quantitative evaluation method of fuzzy mathematics is improved based on a previous study.First,the single-factor membership degree is determined using the dynamic clustering method,then a single-factor evaluation matrix is constructed using a continuous grading function,and finally,the probability distribution of the evaluation grade in a fuzzy evaluation matrix is analyzed.In this study,taking the F1 fault located in the northeastern Chepaizi Bulge as an example,the sealing properties of faults in different strata are quantitatively evaluated using both an improved and an un-improved comprehensive fuzzy mathematics quantitative evaluation method.Based on current oil and gas distribution,it is found that our evaluation results before and after improvement are significantly different.For faults in＂best＂and＂poorest＂intervals,our evaluation results are consistent with oil and gas distribution.However,for the faults in＂good＂or＂poor＂intervals,our evaluation is not completelyconsistent with oil and gas distribution.The improved evaluation results reflect the overall and local sealing properties of target zones and embody the nonuniformity of fault sealing,indicating the improved method is more suitable for evaluating fault sealing under complicated conditions.展开更多
在高内压循环作用下地下储气库衬砌易产生裂缝与渗透通道,密封层受力与裂缝控制问题尤为关键。基于有限-离散元方法(finite-discrete element method,简称FDEM),建立了连续-非连续的围岩-衬砌-密封层整体模型,系统研究了平钢板与波拱两...在高内压循环作用下地下储气库衬砌易产生裂缝与渗透通道,密封层受力与裂缝控制问题尤为关键。基于有限-离散元方法(finite-discrete element method,简称FDEM),建立了连续-非连续的围岩-衬砌-密封层整体模型,系统研究了平钢板与波拱两类钢衬及预设缝设计参数对衬砌裂缝演化与密封性能的影响。结果表明,平钢板型密封层应力水平和裂缝数量较高,整体性差,预设缝改善衬砌开裂与密封结构受力作用有限;波拱型结构能显著降低峰值应力并改变裂缝分布,使得裂缝多集中在波拱底部,整体裂缝数量减少,但波拱处的裂缝开裂宽度更大。采用波拱+预设缝相结合的方案可进一步均匀化开裂,减少密封钢衬应力。随着波拱和预设缝数量增加,应力分布趋于均匀,裂缝扩展受控,但最大裂缝宽度呈先减后增趋势,钢衬应力模式由拉应力向弯-剪应力转变。当缝设于拱底时,裂缝可沿预设路径均匀扩展,并可结合防排水措施降低渗透风险。总体而言,波拱+预设缝复合设计在引导裂缝、释放应变和提升密封渗透性能方面具有显著优势,为储气库密封-衬砌协同优化设计提供参考。展开更多
An approach for analyzing and optimizing sealing mechanism of ball valve made of nitrile butadiene rubber(NBR) with finite element method was presented. The Mooney-Rivlin hyperelastic material model was chosen to char...An approach for analyzing and optimizing sealing mechanism of ball valve made of nitrile butadiene rubber(NBR) with finite element method was presented. The Mooney-Rivlin hyperelastic material model was chosen to characterize NBR sealing, as it has been recommended in the similar applications. That is, NBR sealing was modeled as incompressible hyperelasticity, as well as the assumption of isotropic flow. The results illustrate the structural pressure and contact pressure on the contact surface, which shows that the NBR sealing mechanism is very suitable for sealing after dimension optimization.展开更多
As one of the main reasons causing leakage heat load in a refrigerator,mass and heat transfer through refrigerator door seal is of great importance to be studied.In this paper,a model is presented for numerical simula...As one of the main reasons causing leakage heat load in a refrigerator,mass and heat transfer through refrigerator door seal is of great importance to be studied.In this paper,a model is presented for numerical simulation of mass and heat transfer process through refrigerator door seal,and an experiment apparatus is designed and set up as well for comparison.A two-dimensional model and tracer gas method are used in simulation and experiment,respectively.It can be found that the relative deviations of air infiltration rate between the simulated results and experimental results were less than 1%,and the temperature difference errors at two special points of the door seal were less than 2.03℃.In conclusion,the simulated results are in good agreement with the experimental results.This paper initially sets up a model that can accurately simulate the heat and mass transfer through the refrigerator door seal,and the model can be used in refrigerator door seal optimization research in the follow-up study.展开更多
Underground mine fire always exists since the mining activity was practiced.It poses a severe safety hazard to the mine workers and may also cause a tremendous economic loss to the mines.Methods for controlling and ex...Underground mine fire always exists since the mining activity was practiced.It poses a severe safety hazard to the mine workers and may also cause a tremendous economic loss to the mines.Methods for controlling and extinguishing fires in underground mine have long been studied and there have been significant improvements.In order to know clearly about the firefighting technology used,this paper summarizes most of the underground mine firefighting methods used in the United States the past 150 years.This paper describes not only the accepted firefighting theories,but also the technologies,both direct and indirect attacking,in accordance to regulations or codes,with special attention is given to the indirect attack method and its related technologies.Further research needed is also briefly discussed at the end of this paper.展开更多
基金supported by the Program of the National Natural Science Foundation of China(Grant No.52371055)the Young Elite Scientist Sponsorship Program Cast(Grant No.YESS20200139)+1 种基金the Basic Scientific Research Project of Liaoning Provincial Department of Education(Grant No.JYTMS20230618)Special thanks are due to the instrumental analysis from the Analytical and Testing Centre,Northeastern University.
文摘A principle was proposed for designing a method to seal anodized aluminum used in semiconductor processing apparatuses.Thermodynamic calculations and Fick’s second law were used to reveal trends in the metal ion deposition,deposition product stability,vapor pressures of halides for selected metal ions,the holding temperature,and time.Interactions between ion concentrations and the sealing temperature were also revealed.According to the design principles,anodized aluminum dipped in 1 mM Cr^(3+)ion solution and steam-sealed for 18 h exhibited the highest corrosion resistance when exposed to 5 wt.%HCl solution and HCl gas,verifying the designed results.
基金supported in part from the Fundamental Research Project funded by the Ministry of Industry and Information Technology of the People’s Republic of China
文摘Many variables affect the sealing performance, and their distribution characteristics are difficult to obtain with probabilistic methods owing to the high cost involved. Numerous problems in engineering are similar due to the appearance of small-sample parameters. In this study, the sealing reliability of an aviation seal was defined as the research object, and an interval uncertainty method and multidimensional response surface were proposed to calculate the sealing reliability.Based on this, we first analyzed the failure mechanism of the aviation seal and established a leakage rate model. Then, based on the non-probabilistic interval model, an interval uncertainty method was proposed to construct the analytical model. With reference to the limit state equation from the structural reliability theory, the multidimensional response surface was used for fast calculation.Then, we chose the single-cylinder gas steering gear used in aircraft as the case study, its sealing reliability in working and non-working statuses were calculated, and the results were verified with the actual maintenance records. By analyzing the sensitivity of some variables, we can improve the sealing reliability of the aviation seal by improving the surface roughness only if the cost allows.Finally, we consider that the method proposed in this study realizes the application of smallsample uncertainty analysis in reliability analysis, and could provide a feasible way to solve the similar problems in engineering with multidimensional and small-sample parameters.
文摘Dear Editor,In a recent interventional case report,Allon et al ）hydrated corneal stroma with cefuroxime to seal a small traumatic leaky corneal perforation that was unresponsive to prior soft bandage contact lens application for 6d.
基金supported by the Science and Technology Project of Universities and Colleges in Shandong Province ‘‘Investigation on diagenetic environment and transformation pattern of red-bed reservoirs in the rift basins’’ (No. J16LH52)
文摘Fuzzy mathematics is an important means to quantitatively evaluate the properties of fault sealing in petroleum reservoirs.To accurately study fault sealing,the comprehensive quantitative evaluation method of fuzzy mathematics is improved based on a previous study.First,the single-factor membership degree is determined using the dynamic clustering method,then a single-factor evaluation matrix is constructed using a continuous grading function,and finally,the probability distribution of the evaluation grade in a fuzzy evaluation matrix is analyzed.In this study,taking the F1 fault located in the northeastern Chepaizi Bulge as an example,the sealing properties of faults in different strata are quantitatively evaluated using both an improved and an un-improved comprehensive fuzzy mathematics quantitative evaluation method.Based on current oil and gas distribution,it is found that our evaluation results before and after improvement are significantly different.For faults in＂best＂and＂poorest＂intervals,our evaluation results are consistent with oil and gas distribution.However,for the faults in＂good＂or＂poor＂intervals,our evaluation is not completelyconsistent with oil and gas distribution.The improved evaluation results reflect the overall and local sealing properties of target zones and embody the nonuniformity of fault sealing,indicating the improved method is more suitable for evaluating fault sealing under complicated conditions.
文摘在高内压循环作用下地下储气库衬砌易产生裂缝与渗透通道,密封层受力与裂缝控制问题尤为关键。基于有限-离散元方法(finite-discrete element method,简称FDEM),建立了连续-非连续的围岩-衬砌-密封层整体模型,系统研究了平钢板与波拱两类钢衬及预设缝设计参数对衬砌裂缝演化与密封性能的影响。结果表明,平钢板型密封层应力水平和裂缝数量较高,整体性差,预设缝改善衬砌开裂与密封结构受力作用有限;波拱型结构能显著降低峰值应力并改变裂缝分布,使得裂缝多集中在波拱底部,整体裂缝数量减少,但波拱处的裂缝开裂宽度更大。采用波拱+预设缝相结合的方案可进一步均匀化开裂,减少密封钢衬应力。随着波拱和预设缝数量增加,应力分布趋于均匀,裂缝扩展受控,但最大裂缝宽度呈先减后增趋势,钢衬应力模式由拉应力向弯-剪应力转变。当缝设于拱底时,裂缝可沿预设路径均匀扩展,并可结合防排水措施降低渗透风险。总体而言,波拱+预设缝复合设计在引导裂缝、释放应变和提升密封渗透性能方面具有显著优势,为储气库密封-衬砌协同优化设计提供参考。
基金supported by Technical Center for High-Performance Valves from the Regional Innovation Center (RIC) Program of the Ministry of Knowledge Economy (MKE),Korea
文摘An approach for analyzing and optimizing sealing mechanism of ball valve made of nitrile butadiene rubber(NBR) with finite element method was presented. The Mooney-Rivlin hyperelastic material model was chosen to characterize NBR sealing, as it has been recommended in the similar applications. That is, NBR sealing was modeled as incompressible hyperelasticity, as well as the assumption of isotropic flow. The results illustrate the structural pressure and contact pressure on the contact surface, which shows that the NBR sealing mechanism is very suitable for sealing after dimension optimization.
基金Supported by the National Science Fund for Distinguished Young Scholar(51525604)111 project B16038
文摘As one of the main reasons causing leakage heat load in a refrigerator,mass and heat transfer through refrigerator door seal is of great importance to be studied.In this paper,a model is presented for numerical simulation of mass and heat transfer process through refrigerator door seal,and an experiment apparatus is designed and set up as well for comparison.A two-dimensional model and tracer gas method are used in simulation and experiment,respectively.It can be found that the relative deviations of air infiltration rate between the simulated results and experimental results were less than 1%,and the temperature difference errors at two special points of the door seal were less than 2.03℃.In conclusion,the simulated results are in good agreement with the experimental results.This paper initially sets up a model that can accurately simulate the heat and mass transfer through the refrigerator door seal,and the model can be used in refrigerator door seal optimization research in the follow-up study.
文摘Underground mine fire always exists since the mining activity was practiced.It poses a severe safety hazard to the mine workers and may also cause a tremendous economic loss to the mines.Methods for controlling and extinguishing fires in underground mine have long been studied and there have been significant improvements.In order to know clearly about the firefighting technology used,this paper summarizes most of the underground mine firefighting methods used in the United States the past 150 years.This paper describes not only the accepted firefighting theories,but also the technologies,both direct and indirect attacking,in accordance to regulations or codes,with special attention is given to the indirect attack method and its related technologies.Further research needed is also briefly discussed at the end of this paper.
