A new approach is proposed in this study for accountable capability improvement based on interpretable capability evaluation using the belief rule base(BRB).Firstly,a capability evaluation model is constructed and opt...A new approach is proposed in this study for accountable capability improvement based on interpretable capability evaluation using the belief rule base(BRB).Firstly,a capability evaluation model is constructed and optimized.Then,the key sub-capabilities are identified by quantitatively calculating the contributions made by each sub-capability to the overall capability.Finally,the overall capability is improved by optimizing the identified key sub-capabilities.The theoretical contributions of the proposed approach are as follows.(i)An interpretable capability evaluation model is constructed by employing BRB which can provide complete access to decision-makers.(ii)Key sub-capabilities are identified according to the quantitative contribution analysis results.(iii)Accountable capability improvement is carried out by only optimizing the identified key sub-capabilities.Case study results show that“Surveillance”,“Positioning”,and“Identification”are identified as key sub-capabilities with a summed contribution of 75.55%in an analytical and deducible fashion based on the interpretable capability evaluation model.As a result,the overall capability is improved by optimizing only the identified key sub-capabilities.The overall capability can be greatly improved from 59.20%to 81.80%with a minimum cost of 397.Furthermore,this paper also investigates how optimizing the BRB with more collected data would affect the evaluation results:only optimizing“Surveillance”and“Positioning”can also improve the overall capability to 81.34%with a cost of 370,which thus validates the efficiency of the proposed approach.展开更多
We systemically investigate optical trapping capability of a kind of tornado waves on Rayleigh particles.Such tornado waves are named as tornado circular Pearcey beams(TCPBs)and produced by combining two circular Pear...We systemically investigate optical trapping capability of a kind of tornado waves on Rayleigh particles.Such tornado waves are named as tornado circular Pearcey beams(TCPBs)and produced by combining two circular Pearcey beams with different radii.Our theoretical exploration delves into various aspects,including the propagation dynamics,energy flux,orbital angular momentum,trapping force,and torque characteristics of TCPBs.The results reveal that the orbital angular momentum,trapping force,and torque of these beams can be finely tuned through the judicious manipulation of their topological charges(l_(1)and l_(2)).Notably,we observe a precise control mechanism wherein the force diminishes with|l_(1)+l_(2)|and|l_(1)-l_(2)|,while the torque exhibits enhancement by decreasing solely with|l_(1)+l_(2)|or increasing with|l_(1)-l_(2)|.These results not only provide quantitative insights into the optical trapping performance of TCPBs but also serve as a valuable reference for the ongoing development of innovative photonic tools.展开更多
Concomitant with the advancement of contemporary medical technology,the significance of perioperative nursing has been increasingly accentuated,necessitating elevated standards for the pedagogy of perioperative nursin...Concomitant with the advancement of contemporary medical technology,the significance of perioperative nursing has been increasingly accentuated,necessitating elevated standards for the pedagogy of perioperative nursing.Presently,the PBL(problem-based learning)pedagogical approach,when integrated with CBL(case-based learning),has garnered considerable interest.An extensive literature review has been conducted to analyze the application of the PBL-CBL fusion in the education of perioperative nursing.Findings indicate that this integrative teaching methodology not only enhances students’theoretical knowledge,practical competencies,and collaborative skills but also contributes to the elevation of teaching quality.In conclusion,the PBL-CBL teaching approach holds immense potential for broader application in perioperative nursing education.Nevertheless,it is imperative to continually refine this combined pedagogical strategy to further enhance the caliber of perioperative nursing instruction and to cultivate a greater number of exceptional nursing professionals in the operating room setting.展开更多
Some research results are given in this paper about burnthrough and hydrogen cracking with a flowing chamber and a loop. Many factors including plate thickness, running rate, heat input and so forth have been studied....Some research results are given in this paper about burnthrough and hydrogen cracking with a flowing chamber and a loop. Many factors including plate thickness, running rate, heat input and so forth have been studied. By experiments it can be found that occurrence of hydrogen cracking can be effectively reduced by properly increasing heat input and using the tempering bead technique.展开更多
Hydrogen induced cracking (HIC) is one of the main problems of in-service welding onto active pipeline. Microstructure and hardness of welded joint have a vital effect on hydrogen induced cracking. The microstructur...Hydrogen induced cracking (HIC) is one of the main problems of in-service welding onto active pipeline. Microstructure and hardness of welded joint have a vital effect on hydrogen induced cracking. The microstructure and hardness of welded joint of XTO pipeline steel were studied using simulation in-service welding device. The results show that the main microstructures of in-service welded seam are grain boundary ferrite , intracrystalline acicular ferrite , as well as small amount of widmanztatten structure. The main microstructures of coarse grain heat-affected zone (CGHAZ) are coarse granular bainite, lath ferrite and martensite. Metastable phases such as martensite and lath ferrite are found in CGHAZ because of the too quick cooling velocity a'nd the hardness of the CGHAZ is high.展开更多
The special subject 'research on life prediction technology of important in-service pressure' mainly analyzes the failure mechanism of large-sized important and criticalin-service pressure vessels under the ac...The special subject 'research on life prediction technology of important in-service pressure' mainly analyzes the failure mechanism of large-sized important and criticalin-service pressure vessels under the action of working medium and investigates safety assessmentand life prediction technology with a view to enhance the operation reliability of in-servicepressure vessels in China. Based on a series of accident investigation and test & measuringresearch, the cause of cracking of catalytic regenerator is analyzed and the in-line non-destructiveexamination method and failure prevention measures for the cracking of catalytic regenerator areproposed.展开更多
The chamber device was designed and set up to simulate the in-service welding. The results show : the t8/5 , t8/3 and inner wall peak temperature Tp decrease with the cooling rate increases. The welding energy is car...The chamber device was designed and set up to simulate the in-service welding. The results show : the t8/5 , t8/3 and inner wall peak temperature Tp decrease with the cooling rate increases. The welding energy is carried off by flowing medium, the cooling rate increases, and many unbalanced microstructures such as granular bainite, martensite and M-A generate ; it worsens the properties of HAZ. Under air-cooling, the cooling rate is slow, the austenite grain grows obviously, the lath ferrite crosses the whole austenite, and it causes the hardness value is also big. The change of HAZ width is not obvious with the increase of cooling rate; and burn-through is not susceptible to the cooling rate. The quench microstructures increase and the hydrogen does not outflow from the HAZ easily when increase the cooling rate, so the susceptibility of hydrogen cracking increases.展开更多
Petrochemical storage tanks are generally inspected when the tank is offline mostly to assess the extent of underside corrosion on the tank floor. Emptying, cleaning and opening a tank for inspection take many months ...Petrochemical storage tanks are generally inspected when the tank is offline mostly to assess the extent of underside corrosion on the tank floor. Emptying, cleaning and opening a tank for inspection take many months and are very expensive. Inspection costs can be reduced significantly by inserting robots through manholes on the tank roof to pertbrm non-destructive testing (NDT). The challenge is to develop robots that can operate safely in explosive and hazardous environments and measure the thickness of floor plates using ultrasound sensors. This paper reports on the development of a small and inexpensive prototype robot (NDTBOT) which is designed to be intrinsically safe for zone zero operation. The robot "hops" across the floor to make measurements, without any external moving parts. The paper describes the design, experimental testing of the NDTBOT and presents results of steel plate thickness measurements made under water.展开更多
The emergence of Y6-type nonfullerene acceptors has greatly enhanced the power conversion efficiency(PCE)of organic solar cells(OSCs).However,which structural feature is responsible for the excellent photovoltaic perf...The emergence of Y6-type nonfullerene acceptors has greatly enhanced the power conversion efficiency(PCE)of organic solar cells(OSCs).However,which structural feature is responsible for the excellent photovoltaic performance is still under debate.In this study,two Y6-like acceptors BDOTP-1 and BDOTP-2 were designed.Different from previous Y6-type acceptors featuring an A–D–Aʹ–D–A structure,BDOTP-1,and BDOTP-2 have no electron-deficient Aʹfragment in the core unit.Instead,there is an electron-rich dibenzodioxine fragment in the core.Although this modification leads to a marked change in the molecular dipole moment,electrostatic potential,frontier orbitals,and energy levels,BDOTP acceptors retain similar three-dimensional packing capability as Y6-type acceptors due to the similar banana-shaped molecular configuration.BDOTP acceptors show good performance in OSCs.High PCEs of up to 18.51%(certified 17.9%)are achieved.This study suggests that the banana-shaped configuration instead of the A–D–Aʹ–D–A structure is likely to be the determining factor in realizing high photovoltaic performance.展开更多
Elbows are the most vulnerable parts in pipeline network systems. The residual stress for in-service welding repair has significant impacts on the mechanical properties of straight pipes and elbows. In this paper,the ...Elbows are the most vulnerable parts in pipeline network systems. The residual stress for in-service welding repair has significant impacts on the mechanical properties of straight pipes and elbows. In this paper,the thermal elastic-plastic finite element method is employed to investigate the mechanical field during the in-service welding. The prediction of residual stress and deformation in the straight pipe and elbow is performed based on the validation of the numerical models. And the effects of the curvature radius and defects on the elbow are investigated. The results show that the residual stress distribution is uneven along various directions after welding. And the mechanical properties of the elbow decrease when the curvature radius is small. Compared to the intact elbow,the residual stress of the elbow with defects concentrates in the defective area. The depth of defect is the main factors affecting the mechanical properties of the elbow. A systematic analysis of the mechanical properties of straight pipes and elbows is proposed to provide guidance to the in-service welding.展开更多
SYSWELD was used to simulate in-service welding process of gas pipeline of X70 pipeline steel. Welding thermal cycle, stress and deformation of in-service welded joint were studied. The results show that peak temperat...SYSWELD was used to simulate in-service welding process of gas pipeline of X70 pipeline steel. Welding thermal cycle, stress and deformation of in-service welded joint were studied. The results show that peak temperature of coarse grain heat-affected zone (CGHAZ) of in-service welding onto gas pipeline is the same with routine welding, but ts/5, ts/3 and ts/1 decrease at certain degree. For the zone near welded seam, axial stress and hoop stress in the inner pipe wall are compressive stress when welding source passes through the cross-section that is studied, but residual axial stress and residual hoop stress after welded are all tensile stress. Transient deformation and residual deformation are all convex deformation compared with the original pipe diameter size. Deformation achieves maximum when welding thermal source passes through the cross-section that is studied and then decreases during the cooling process after welding.展开更多
The software of SYSWELD was used to build model and simulate thermal cycle of in-service welding onto active gas pipeline. Influence of pipe diameter, wall thickness and heat input on thermal cycle was studied. The re...The software of SYSWELD was used to build model and simulate thermal cycle of in-service welding onto active gas pipeline. Influence of pipe diameter, wall thickness and heat input on thermal cycle was studied. The results show that t8/5 , t8/3 and peak temperature of inner surface decrease when wall thickness increases from 5 mm to 12 mm. But t8/1 will increases with the increase of wall thickness and will decrease after the wall thickness is larger than 7 mm. Pipe diameter has little influence on thermal cycle and that influence can be ignored when pipe diameter is greater than 273 mm. t8/5 , t8/3 , t8/1 and peak temperature of inner surface will increase with the increase of heat input.展开更多
Malaria is generally considered a major public health problem in Somalia. Providing early diagnosis and effective treatment is the key element of malaria control strategies in malaria-endemic countries, including Soma...Malaria is generally considered a major public health problem in Somalia. Providing early diagnosis and effective treatment is the key element of malaria control strategies in malaria-endemic countries, including Somalia. This required to advocate and ensure health worker’s adherence to the national malaria guidelines at all levels of health care service. A well-designed in-service training program may improve the level of health worker’s adherence to national malaria treatment guidelines, although results have been inconsistent. This is an interventional health facility-based pre and post comparative study aimed to assess the effect of an in-service training program on the practice of healthcare workers toward malaria prevention and treatment guidelines, during in pregnancy in health facilities in Jowhar district, Middle Shabelle region of Somalia. The study was implemented in three phases: pre-intervention phase, intervention phase and post-intervention phase. The sample size consisted of (n = 150) health workers who were selected from ten public health facilities using proportional to size sampling;the data collection adopted in this research is composed of a structured interview questionnaire and observational checklist. Data was analyzed through the application of descriptive statistical analysis that includes frequency and percentage and the Chi-square (x<sup>2</sup>) test was used to test the associations among variables using SPSS software version 25. The study showed that the level of health workers’ awareness of the national malaria guidelines in the treatment and prevention of malaria in pregnancy was found to be good before the intervention 89 (59.3%) and this proportion increased to 150 (100%) post-intervention of the training program. A significance difference has been observed between health workers’ awareness and their adherence to the malarial guidelines at pre-test and post-test with a p-value 0.000. The proportion of health workers who attended previous training on national malaria guidelines in the treatment and prevention of malaria in pregnancy increased from 46 (30.7%) at the pre-test to 150 (100%) after the post-test. A significant difference was observed in the training status among different categories of health worker and their adherence to the guidelines during the pre- and post-intervention of the training program, with a p-value of 0.000. The result showed that health workers were adhering to the guidelines at the pre-test 33 (22%), this increased after the post-test to 87 (58%). The knowledge of the need to adhere led to an increase in the adherence rate after the training program intervention. The study reveals that inadequate awareness was most reason for the non-adherence in the majority of the health workers as indicated by 89 (59.3%) at the pre-test and 56 (37.3%) in the post-test. However, difference was not significant between the availability of anti-malaria drugs in the facilities and the health workers’ adherence to the guidelines p-value 0.355 at the pretest and p-value 0.258 at post-test. The study concluded that the in-service training program significantly improved health workers’ knowledge and practice to the national malaria guidelines in the treatment, and prevention of malaria in pregnancy. The researcher recommends that the national malaria control programme (NMCP) of the Federal Ministry of Health should provide continuous regular in-service training to frontline healthcare workers at (facility and Community-based) to upgrade their skills and knowledge towards the malaria guidelines, disseminate job aids to the health facilities and undertake regular monitoring to ensure effective implementation of the national malaria treatment guidelines in the treatment and prevention of malaria in pregnancy in achieving desired proper case-management practices of malaria in pregnancy at all levels of health care service.展开更多
<strong>Objective:</strong> To investigate and analyze the current status of continuing nursing education (CNE) of in-service nurses in Tibet and their demand for continuing education. <strong>Method...<strong>Objective:</strong> To investigate and analyze the current status of continuing nursing education (CNE) of in-service nurses in Tibet and their demand for continuing education. <strong>Methods:</strong> 663 active nurses in Tibet were taken as the research objects, and the self-developed questionnaire was used to investigate the current status and needs of CNE, and the correlation between the CNE needs of active nurses and their personal conditions was analyzed. <strong>Results:</strong> This study shows that 65.61% (435/663) of active nurses have not participated in any CNE, and 91.86% (609/663) of active nurses believe that they need to participate in CNE. The problems faced by active nurses in participating in CNE include funding restrictions, time limitation and ability limitation. Logistic stepwise regression analysis reveals that the age of active nurses and working years of nurses are negatively correlated with the funding restrictions for participating in CNE (P < 0.05). It is relatively more difficult for young nurses with less working experience to obtain funding for participating in CNE. Moreover, there is a negative correlation between age, educational level and the ability of nurses to participate in CNE (P < 0.05). Younger nurses with lower educational level are more difficult to participate in CNE due to personal ability. There is a positive correlation between the length of working experience and the time limitation faced to participate in CNE (P < 0.05). Senior nurses are too busy with their work to participate in CNE due to limited time. <strong>Conclusion:</strong> The problems faced by active nurses in Tibet in participating in CNE come from funding, time and ability. Young nurses with limited working experience cannot participate in CNE resulting from limited ability and funds;while senior nurses are mainly restricted by time. It is recommended that hospitals and nursing management in Tibet should solve these problems faced by nurses in participating in CNE by implementing a flexible scheduling system, and providing funding or implementing an incentive system, to enhance the confidence of active nurses in participating in CNE.展开更多
In-service structural health monitoring(SHM) technologies are critical for the utilization of composite aircraft structures. We developed a Lamb wave-based in-service SHM technology using built-in piezoelectric actu...In-service structural health monitoring(SHM) technologies are critical for the utilization of composite aircraft structures. We developed a Lamb wave-based in-service SHM technology using built-in piezoelectric actuator/sensor networks to monitor delamination extension in a full-scale composite horizontal tail. The in-service SHM technology combine of damage rapid monitoring(DRM) stage and damage imaging diagnosis(DID) stage allows for real-time monitoring and long term tracking of the structural integrity of composite aircraft structures. DRM stage using spearman rank correlation coeffi cient was introduced to generate a damage index which can be used to monitor the trend of damage extension. The DID stage based on canonical correlation analysis aimed at intuitively highlighting structural damage regions in two-dimensional images. The DRM and DID stages were trialed by an in-service SHM experiment of CFRP T-joint. Finally, the detection capability of the in-service SHM technology was verified in the SHM experiment of a full-scale composite horizontal tail. Experimental results show that the rapid monitoring method effectively monitors the damage occurrence and extension tendency in real time; damage imaging diagnosis results are consistent with those from the failure model of the composite horizontal tail structure.展开更多
The effective plugging of artificial fractures is key to the success of temporary plugging and diverting fracturing technology,which is one of the most promising ways to improve the heat recovery efficiency of hot dry...The effective plugging of artificial fractures is key to the success of temporary plugging and diverting fracturing technology,which is one of the most promising ways to improve the heat recovery efficiency of hot dry rock.At present,how temporary plugging agents plug artificial fractures under high temperature remains unclear.In this paper,by establishing an improved experimental system for the evaluation of temporary plugging performance at high temperature,we clarified the effects of high temperature,injection rate,and fracture width on the pressure response and plugging efficiency of the fracture.The results revealed that the temporary plugging process of artificial fractures in hot dry rock can be divided into four main stages:the initial stage of temporary plugging,the bridging stage of the particles,the plugging formation stage,and the high-pressure dense plugging stage.As the temperature increases,the distribution distance of the temporary plugging agent,the number of pressure fluctuations,and the time required for crack plugging increases.Particularly,when the temperature increases by 100℃,the complete plugging time increases by 90.7%.展开更多
Antimony(Sb) is an attractive cathode for liquid metal batteries(LMBs) because of its high theoretical voltage and low cost.The main obstacles associated with the Sb-based cathodes are unsatisfactory energy density an...Antimony(Sb) is an attractive cathode for liquid metal batteries(LMBs) because of its high theoretical voltage and low cost.The main obstacles associated with the Sb-based cathodes are unsatisfactory energy density and poor rate-capability.Herein,we propose a novel Sb_(64)Cu_(36)cathode that effectively tackles these issues.The Sb_(64)Cu_(36)(melting point:525℃) cathode presents a novel lithiation mechanism involving sequentially the generation of Li_(2)CuSb,the formation of Li_(3)Sb,and the conversion reaction of Li_(2)CuSb to Li_(3)Sb and Cu.The generated intermetallic compounds show a unique microstructure of the upper floated Li_(2)CuSb layer and the below cross-linked structure with interpenetrated Li_(2)CuSb and Li_(3)Sb phases.Compared with Li_(3)Sb,the lower Li migration energy barrier(0.188 eV) of Li_(2)CuSb significantly facilitates the lithium diffusion across the intermediate compounds and accelerates the reaction kinetics.Consequently,the Li‖Sb_(64)Cu_(36)cell delivers a more excellent electrochemical performance(energy density:353 W h kg^(-1)at 0.4 A cm^(-2);rate capability:0.59 V at 2.0 A cm^(-2)),and a much lower energy storage cost of only 38.45 $ kW h^(-1)than other previously reported Sb-based LMBs.This work provides a novel cathode design concept for the development of high-performance LMBs in applications for large-scale energy storage.展开更多
基金supported by the National Natural Science Foundation of China(72471067,72431011,72471238,72231011,62303474,72301286)the Fundamental Research Funds for the Provincial Universities of Zhejiang(GK239909299001-010).
文摘A new approach is proposed in this study for accountable capability improvement based on interpretable capability evaluation using the belief rule base(BRB).Firstly,a capability evaluation model is constructed and optimized.Then,the key sub-capabilities are identified by quantitatively calculating the contributions made by each sub-capability to the overall capability.Finally,the overall capability is improved by optimizing the identified key sub-capabilities.The theoretical contributions of the proposed approach are as follows.(i)An interpretable capability evaluation model is constructed by employing BRB which can provide complete access to decision-makers.(ii)Key sub-capabilities are identified according to the quantitative contribution analysis results.(iii)Accountable capability improvement is carried out by only optimizing the identified key sub-capabilities.Case study results show that“Surveillance”,“Positioning”,and“Identification”are identified as key sub-capabilities with a summed contribution of 75.55%in an analytical and deducible fashion based on the interpretable capability evaluation model.As a result,the overall capability is improved by optimizing only the identified key sub-capabilities.The overall capability can be greatly improved from 59.20%to 81.80%with a minimum cost of 397.Furthermore,this paper also investigates how optimizing the BRB with more collected data would affect the evaluation results:only optimizing“Surveillance”and“Positioning”can also improve the overall capability to 81.34%with a cost of 370,which thus validates the efficiency of the proposed approach.
基金Project supported by the National Natural Science Foundation of China(Grant No.11604058)the Guangxi Natural Science Foundation(Grant Nos.2020GXNSFAA297041 and 2023JJA110112)the Innovation Project of Guangxi Graduate Education(Grant No.YCSW2023083)。
文摘We systemically investigate optical trapping capability of a kind of tornado waves on Rayleigh particles.Such tornado waves are named as tornado circular Pearcey beams(TCPBs)and produced by combining two circular Pearcey beams with different radii.Our theoretical exploration delves into various aspects,including the propagation dynamics,energy flux,orbital angular momentum,trapping force,and torque characteristics of TCPBs.The results reveal that the orbital angular momentum,trapping force,and torque of these beams can be finely tuned through the judicious manipulation of their topological charges(l_(1)and l_(2)).Notably,we observe a precise control mechanism wherein the force diminishes with|l_(1)+l_(2)|and|l_(1)-l_(2)|,while the torque exhibits enhancement by decreasing solely with|l_(1)+l_(2)|or increasing with|l_(1)-l_(2)|.These results not only provide quantitative insights into the optical trapping performance of TCPBs but also serve as a valuable reference for the ongoing development of innovative photonic tools.
文摘Concomitant with the advancement of contemporary medical technology,the significance of perioperative nursing has been increasingly accentuated,necessitating elevated standards for the pedagogy of perioperative nursing.Presently,the PBL(problem-based learning)pedagogical approach,when integrated with CBL(case-based learning),has garnered considerable interest.An extensive literature review has been conducted to analyze the application of the PBL-CBL fusion in the education of perioperative nursing.Findings indicate that this integrative teaching methodology not only enhances students’theoretical knowledge,practical competencies,and collaborative skills but also contributes to the elevation of teaching quality.In conclusion,the PBL-CBL teaching approach holds immense potential for broader application in perioperative nursing education.Nevertheless,it is imperative to continually refine this combined pedagogical strategy to further enhance the caliber of perioperative nursing instruction and to cultivate a greater number of exceptional nursing professionals in the operating room setting.
文摘Some research results are given in this paper about burnthrough and hydrogen cracking with a flowing chamber and a loop. Many factors including plate thickness, running rate, heat input and so forth have been studied. By experiments it can be found that occurrence of hydrogen cracking can be effectively reduced by properly increasing heat input and using the tempering bead technique.
文摘Hydrogen induced cracking (HIC) is one of the main problems of in-service welding onto active pipeline. Microstructure and hardness of welded joint have a vital effect on hydrogen induced cracking. The microstructure and hardness of welded joint of XTO pipeline steel were studied using simulation in-service welding device. The results show that the main microstructures of in-service welded seam are grain boundary ferrite , intracrystalline acicular ferrite , as well as small amount of widmanztatten structure. The main microstructures of coarse grain heat-affected zone (CGHAZ) are coarse granular bainite, lath ferrite and martensite. Metastable phases such as martensite and lath ferrite are found in CGHAZ because of the too quick cooling velocity a'nd the hardness of the CGHAZ is high.
基金important scientech problemtackling subject foundation under the state 9th 5-year plan(no.96-918-02-04).
文摘The special subject 'research on life prediction technology of important in-service pressure' mainly analyzes the failure mechanism of large-sized important and criticalin-service pressure vessels under the action of working medium and investigates safety assessmentand life prediction technology with a view to enhance the operation reliability of in-servicepressure vessels in China. Based on a series of accident investigation and test & measuringresearch, the cause of cracking of catalytic regenerator is analyzed and the in-line non-destructiveexamination method and failure prevention measures for the cracking of catalytic regenerator areproposed.
文摘The chamber device was designed and set up to simulate the in-service welding. The results show : the t8/5 , t8/3 and inner wall peak temperature Tp decrease with the cooling rate increases. The welding energy is carried off by flowing medium, the cooling rate increases, and many unbalanced microstructures such as granular bainite, martensite and M-A generate ; it worsens the properties of HAZ. Under air-cooling, the cooling rate is slow, the austenite grain grows obviously, the lath ferrite crosses the whole austenite, and it causes the hardness value is also big. The change of HAZ width is not obvious with the increase of cooling rate; and burn-through is not susceptible to the cooling rate. The quench microstructures increase and the hydrogen does not outflow from the HAZ easily when increase the cooling rate, so the susceptibility of hydrogen cracking increases.
文摘Petrochemical storage tanks are generally inspected when the tank is offline mostly to assess the extent of underside corrosion on the tank floor. Emptying, cleaning and opening a tank for inspection take many months and are very expensive. Inspection costs can be reduced significantly by inserting robots through manholes on the tank roof to pertbrm non-destructive testing (NDT). The challenge is to develop robots that can operate safely in explosive and hazardous environments and measure the thickness of floor plates using ultrasound sensors. This paper reports on the development of a small and inexpensive prototype robot (NDTBOT) which is designed to be intrinsically safe for zone zero operation. The robot "hops" across the floor to make measurements, without any external moving parts. The paper describes the design, experimental testing of the NDTBOT and presents results of steel plate thickness measurements made under water.
基金the open research fund of the Songshan Lake Materials Laboratory(2021SLABFK02)the National Key Research and Development Program of China(2017YFA0206600)the National Natural Science Foundation of China(51922032 and 21961160720).
文摘The emergence of Y6-type nonfullerene acceptors has greatly enhanced the power conversion efficiency(PCE)of organic solar cells(OSCs).However,which structural feature is responsible for the excellent photovoltaic performance is still under debate.In this study,two Y6-like acceptors BDOTP-1 and BDOTP-2 were designed.Different from previous Y6-type acceptors featuring an A–D–Aʹ–D–A structure,BDOTP-1,and BDOTP-2 have no electron-deficient Aʹfragment in the core unit.Instead,there is an electron-rich dibenzodioxine fragment in the core.Although this modification leads to a marked change in the molecular dipole moment,electrostatic potential,frontier orbitals,and energy levels,BDOTP acceptors retain similar three-dimensional packing capability as Y6-type acceptors due to the similar banana-shaped molecular configuration.BDOTP acceptors show good performance in OSCs.High PCEs of up to 18.51%(certified 17.9%)are achieved.This study suggests that the banana-shaped configuration instead of the A–D–Aʹ–D–A structure is likely to be the determining factor in realizing high photovoltaic performance.
基金supported by the Natural Science Foundation of Shandong Province(No.ZR2018MEE012)China University of Petroleum(East China)Graduate Innovation Project(No.YCX2017052)
文摘Elbows are the most vulnerable parts in pipeline network systems. The residual stress for in-service welding repair has significant impacts on the mechanical properties of straight pipes and elbows. In this paper,the thermal elastic-plastic finite element method is employed to investigate the mechanical field during the in-service welding. The prediction of residual stress and deformation in the straight pipe and elbow is performed based on the validation of the numerical models. And the effects of the curvature radius and defects on the elbow are investigated. The results show that the residual stress distribution is uneven along various directions after welding. And the mechanical properties of the elbow decrease when the curvature radius is small. Compared to the intact elbow,the residual stress of the elbow with defects concentrates in the defective area. The depth of defect is the main factors affecting the mechanical properties of the elbow. A systematic analysis of the mechanical properties of straight pipes and elbows is proposed to provide guidance to the in-service welding.
文摘SYSWELD was used to simulate in-service welding process of gas pipeline of X70 pipeline steel. Welding thermal cycle, stress and deformation of in-service welded joint were studied. The results show that peak temperature of coarse grain heat-affected zone (CGHAZ) of in-service welding onto gas pipeline is the same with routine welding, but ts/5, ts/3 and ts/1 decrease at certain degree. For the zone near welded seam, axial stress and hoop stress in the inner pipe wall are compressive stress when welding source passes through the cross-section that is studied, but residual axial stress and residual hoop stress after welded are all tensile stress. Transient deformation and residual deformation are all convex deformation compared with the original pipe diameter size. Deformation achieves maximum when welding thermal source passes through the cross-section that is studied and then decreases during the cooling process after welding.
基金Sponsored by Scientific Research Fund for Doctors(Y040312)Innovation Fund for Doctors(B2005-3) of China University of Petroleum
文摘The software of SYSWELD was used to build model and simulate thermal cycle of in-service welding onto active gas pipeline. Influence of pipe diameter, wall thickness and heat input on thermal cycle was studied. The results show that t8/5 , t8/3 and peak temperature of inner surface decrease when wall thickness increases from 5 mm to 12 mm. But t8/1 will increases with the increase of wall thickness and will decrease after the wall thickness is larger than 7 mm. Pipe diameter has little influence on thermal cycle and that influence can be ignored when pipe diameter is greater than 273 mm. t8/5 , t8/3 , t8/1 and peak temperature of inner surface will increase with the increase of heat input.
文摘Malaria is generally considered a major public health problem in Somalia. Providing early diagnosis and effective treatment is the key element of malaria control strategies in malaria-endemic countries, including Somalia. This required to advocate and ensure health worker’s adherence to the national malaria guidelines at all levels of health care service. A well-designed in-service training program may improve the level of health worker’s adherence to national malaria treatment guidelines, although results have been inconsistent. This is an interventional health facility-based pre and post comparative study aimed to assess the effect of an in-service training program on the practice of healthcare workers toward malaria prevention and treatment guidelines, during in pregnancy in health facilities in Jowhar district, Middle Shabelle region of Somalia. The study was implemented in three phases: pre-intervention phase, intervention phase and post-intervention phase. The sample size consisted of (n = 150) health workers who were selected from ten public health facilities using proportional to size sampling;the data collection adopted in this research is composed of a structured interview questionnaire and observational checklist. Data was analyzed through the application of descriptive statistical analysis that includes frequency and percentage and the Chi-square (x<sup>2</sup>) test was used to test the associations among variables using SPSS software version 25. The study showed that the level of health workers’ awareness of the national malaria guidelines in the treatment and prevention of malaria in pregnancy was found to be good before the intervention 89 (59.3%) and this proportion increased to 150 (100%) post-intervention of the training program. A significance difference has been observed between health workers’ awareness and their adherence to the malarial guidelines at pre-test and post-test with a p-value 0.000. The proportion of health workers who attended previous training on national malaria guidelines in the treatment and prevention of malaria in pregnancy increased from 46 (30.7%) at the pre-test to 150 (100%) after the post-test. A significant difference was observed in the training status among different categories of health worker and their adherence to the guidelines during the pre- and post-intervention of the training program, with a p-value of 0.000. The result showed that health workers were adhering to the guidelines at the pre-test 33 (22%), this increased after the post-test to 87 (58%). The knowledge of the need to adhere led to an increase in the adherence rate after the training program intervention. The study reveals that inadequate awareness was most reason for the non-adherence in the majority of the health workers as indicated by 89 (59.3%) at the pre-test and 56 (37.3%) in the post-test. However, difference was not significant between the availability of anti-malaria drugs in the facilities and the health workers’ adherence to the guidelines p-value 0.355 at the pretest and p-value 0.258 at post-test. The study concluded that the in-service training program significantly improved health workers’ knowledge and practice to the national malaria guidelines in the treatment, and prevention of malaria in pregnancy. The researcher recommends that the national malaria control programme (NMCP) of the Federal Ministry of Health should provide continuous regular in-service training to frontline healthcare workers at (facility and Community-based) to upgrade their skills and knowledge towards the malaria guidelines, disseminate job aids to the health facilities and undertake regular monitoring to ensure effective implementation of the national malaria treatment guidelines in the treatment and prevention of malaria in pregnancy in achieving desired proper case-management practices of malaria in pregnancy at all levels of health care service.
文摘<strong>Objective:</strong> To investigate and analyze the current status of continuing nursing education (CNE) of in-service nurses in Tibet and their demand for continuing education. <strong>Methods:</strong> 663 active nurses in Tibet were taken as the research objects, and the self-developed questionnaire was used to investigate the current status and needs of CNE, and the correlation between the CNE needs of active nurses and their personal conditions was analyzed. <strong>Results:</strong> This study shows that 65.61% (435/663) of active nurses have not participated in any CNE, and 91.86% (609/663) of active nurses believe that they need to participate in CNE. The problems faced by active nurses in participating in CNE include funding restrictions, time limitation and ability limitation. Logistic stepwise regression analysis reveals that the age of active nurses and working years of nurses are negatively correlated with the funding restrictions for participating in CNE (P < 0.05). It is relatively more difficult for young nurses with less working experience to obtain funding for participating in CNE. Moreover, there is a negative correlation between age, educational level and the ability of nurses to participate in CNE (P < 0.05). Younger nurses with lower educational level are more difficult to participate in CNE due to personal ability. There is a positive correlation between the length of working experience and the time limitation faced to participate in CNE (P < 0.05). Senior nurses are too busy with their work to participate in CNE due to limited time. <strong>Conclusion:</strong> The problems faced by active nurses in Tibet in participating in CNE come from funding, time and ability. Young nurses with limited working experience cannot participate in CNE resulting from limited ability and funds;while senior nurses are mainly restricted by time. It is recommended that hospitals and nursing management in Tibet should solve these problems faced by nurses in participating in CNE by implementing a flexible scheduling system, and providing funding or implementing an incentive system, to enhance the confidence of active nurses in participating in CNE.
基金Funded by the National Natural Science Foundation of China(Nos.11172053 and 91016024)the New Century Excellent Talents in University(NCET-11-0055)the Fundamental Research Funds for the Central Universities(DUT13ZD(G)06)
文摘In-service structural health monitoring(SHM) technologies are critical for the utilization of composite aircraft structures. We developed a Lamb wave-based in-service SHM technology using built-in piezoelectric actuator/sensor networks to monitor delamination extension in a full-scale composite horizontal tail. The in-service SHM technology combine of damage rapid monitoring(DRM) stage and damage imaging diagnosis(DID) stage allows for real-time monitoring and long term tracking of the structural integrity of composite aircraft structures. DRM stage using spearman rank correlation coeffi cient was introduced to generate a damage index which can be used to monitor the trend of damage extension. The DID stage based on canonical correlation analysis aimed at intuitively highlighting structural damage regions in two-dimensional images. The DRM and DID stages were trialed by an in-service SHM experiment of CFRP T-joint. Finally, the detection capability of the in-service SHM technology was verified in the SHM experiment of a full-scale composite horizontal tail. Experimental results show that the rapid monitoring method effectively monitors the damage occurrence and extension tendency in real time; damage imaging diagnosis results are consistent with those from the failure model of the composite horizontal tail structure.
基金supported financially by the Beijing Natural Science Foundation Project(No.3222030)the National Natural Science Foundation of China(No.51936001,No.52274002 and No.52192622)+1 种基金the PetroChina Science and Technology Innovation Foundation Project(2021DQ02–0201)Award Cultivation Foundation from Beijing Institute of Petrochemical Technology(No.BIPTACF-002).
文摘The effective plugging of artificial fractures is key to the success of temporary plugging and diverting fracturing technology,which is one of the most promising ways to improve the heat recovery efficiency of hot dry rock.At present,how temporary plugging agents plug artificial fractures under high temperature remains unclear.In this paper,by establishing an improved experimental system for the evaluation of temporary plugging performance at high temperature,we clarified the effects of high temperature,injection rate,and fracture width on the pressure response and plugging efficiency of the fracture.The results revealed that the temporary plugging process of artificial fractures in hot dry rock can be divided into four main stages:the initial stage of temporary plugging,the bridging stage of the particles,the plugging formation stage,and the high-pressure dense plugging stage.As the temperature increases,the distribution distance of the temporary plugging agent,the number of pressure fluctuations,and the time required for crack plugging increases.Particularly,when the temperature increases by 100℃,the complete plugging time increases by 90.7%.
基金financially supported by the National Natural Science Foundation of China(52074023)the Beijing Natural Science Foundation(2222062)+1 种基金the National Key R&D Program of China(2018YFB0905600)the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities)(FRF-IDRY-21-023)。
文摘Antimony(Sb) is an attractive cathode for liquid metal batteries(LMBs) because of its high theoretical voltage and low cost.The main obstacles associated with the Sb-based cathodes are unsatisfactory energy density and poor rate-capability.Herein,we propose a novel Sb_(64)Cu_(36)cathode that effectively tackles these issues.The Sb_(64)Cu_(36)(melting point:525℃) cathode presents a novel lithiation mechanism involving sequentially the generation of Li_(2)CuSb,the formation of Li_(3)Sb,and the conversion reaction of Li_(2)CuSb to Li_(3)Sb and Cu.The generated intermetallic compounds show a unique microstructure of the upper floated Li_(2)CuSb layer and the below cross-linked structure with interpenetrated Li_(2)CuSb and Li_(3)Sb phases.Compared with Li_(3)Sb,the lower Li migration energy barrier(0.188 eV) of Li_(2)CuSb significantly facilitates the lithium diffusion across the intermediate compounds and accelerates the reaction kinetics.Consequently,the Li‖Sb_(64)Cu_(36)cell delivers a more excellent electrochemical performance(energy density:353 W h kg^(-1)at 0.4 A cm^(-2);rate capability:0.59 V at 2.0 A cm^(-2)),and a much lower energy storage cost of only 38.45 $ kW h^(-1)than other previously reported Sb-based LMBs.This work provides a novel cathode design concept for the development of high-performance LMBs in applications for large-scale energy storage.