At the end of September, banners carrying the slogan "Catch one thief, get 1,000yuan" appeared in Gulou District of Fuzhou,capital of southeast China’s Fujian Province.According to local officials, the goal of
The microenvironment,which involves pollutant dispersion of the urban street canyon,is critical to the health of pedestrians and residents.The objectives of this work are twofold:(i)to effectively assess the pollutant...The microenvironment,which involves pollutant dispersion of the urban street canyon,is critical to the health of pedestrians and residents.The objectives of this work are twofold:(i)to effectively assess the pollutant dispersion process based on a theory and(ii)to adopt an appropriate stratigy,i.e.,wind catcher,to alleviate the pollution in the street canyons.Pollutant dispersion in street canyons is essentially a convective mass transfer process.Because the convective heat transfer process and the mass transfer process are physically similar and the applicability of field synergy theory to turbulence has been verified in the literature,we apply the field synergy theory to the study of pollutant dispersion in street canyons.In this paper,a computational fluid dynamics(CFD)simulation is conducted to investigate the effects of wind catcher,wind speed and the geometry of the street canyons on pollutant dispersion.According to the field synergy theory,Sherwood number and field synergy number are used to quantitatively evaluate the wind catcher and wind speed on the diffusion of pollutants in asymmetric street canyons.The results show that adding wind catchers can significantly improve the air quality of the step-down street canyon and reduce the average pollutant concentrations in the street canyon by 75%.Higher wind speed enhances diffusion of pollutants differently in different geometric street canyons.展开更多
In an active magnetic bearing (AMB) system, the catcher bearings (CBs) are indispensable to protect the rotor and stator in case the magnetic bearings fail. Most of the former researches associated with CBs are ma...In an active magnetic bearing (AMB) system, the catcher bearings (CBs) are indispensable to protect the rotor and stator in case the magnetic bearings fail. Most of the former researches associated with CBs are mainly focused on the dynamic responses of the rotor drops onto traditional single-decker catcher bearings (SDCBs). But because of the lower limited speed of SDCB, it cannot withstand the ultra high speed rotation after rotor drop. In this paper, based on the analysis of the disadvantages of SDCBs, a new type of double-decker catcher bearings (DDCBs) is proposed to enhance the CB work performance in AMB system. In order to obtain thc accurate rotor movements before AMB failure, the dynamic characteristics of AMB are theoretically derived. Detailed simulation models containing rigid rotor model, contact model between rotor and inner race, DDCB force model as well as heating model after rotor drop are established. Then, using those established models the dynamic responses of rotor drops onto DDCBs and SDCBs are respectively simulated. The rotor orbits, contact forces, spin speeds of various parts and heat energies after AMB failure are mainly analyzed. The simulation results show that DDCBs can effectively improve the CBs limit rotational speed and reduce the following vibrations, impacts and heating. Finally, rotor drop experiments choosing different types of CBs are carried out on the established AMB test bench. Rotor orbits, inner race temperatures as well as the rotating speeds of both inner race and intermediate races after rotor drop are synchronously measured. The experiment results verify the advantages of DDCB and the correctness of theoretical analysis. The studies provide certain theoretical and experimental references for the application of DDCBs in AMB system.展开更多
To mitigate consequences of core melting,an ex-vessel core catcher is investigated in this study.Instructions should be obeyed to cool down the corium caused by core melting.The corium destroys the reactor containment...To mitigate consequences of core melting,an ex-vessel core catcher is investigated in this study.Instructions should be obeyed to cool down the corium caused by core melting.The corium destroys the reactor containment and causes radioactive materials to be released into the environment if it does not cool down well.It is important to build a core catcher system for the reception,localization,and cool down of the molten corium during a severe accident resulting from core melting.In this study,the role of a core catcher in the VVER-1000/v528 reactor containment during a station black out(SBO)accident is evaluated using the MELCOR1.8.6 code.In addition,parametric analyses of the SBO for(i)SBO accidents with emergency core cooling system(ECCS)operation,and(ii)without ECCS operation are performed.Furthermore,thermal–hydraulic analyses in dry and wet cavities with/without water are conducted.The investigations include the reduction of gases resulting from molten–corium–concrete interactions(H_(2),CO,CO_(2)).Core melting,gas production,and the pressure/temperature in the reactor containment are assessed.Additionally,a full investigation pertaining to gas release(H_(2),CO,CO_(2))and the pressure/temperature of the core catcher is performed.Based on MELCOR simulations,a core cavity and a perimeter water channel are the best options for corium cooling and a lower radionuclide release.This simulation is also theoretically investigated and discussed herein.The simulation results show that the core catcher system in addition to an internal sacrificial material reduces the containment pressure from 689 to 580 kPa and the corresponding temperature from 394 to 380 K.Furthermore,it is observed that the amount of gases produced,particularly hydrogen,decreased from 1698 to 1235 kg.Moreover,the presence of supporting systems,including an ECCS with a core catcher,prolonged the core melting time from 16,430 to 28,630 s(in an SBO accident)and significantly decreased the gases produced.展开更多
In an active magnetic bearing(AMB)system,the catcher bearings(CBs)are indispensable to protect the rotor and stator in case the magnetic bearings fail or overload.A new CB structure composed of two ball bearings is in...In an active magnetic bearing(AMB)system,the catcher bearings(CBs)are indispensable to protect the rotor and stator in case the magnetic bearings fail or overload.A new CB structure composed of two ball bearings is introduced.Detailed simulation models containing contact model between rotor and inner race,double-decker catcher bearing(DDCB)model as well as single-decker catcher bearing(SDCB)model are established using multibody dynamics simulation software MSC.ADAMS.Then,using those established models,the rotor orbits and the contact forces between rotor and inner race are simulated respectively after rotor drop on DDCBs and SDCBs.The simulation result shows that the rotor vibration range using DDCBs is significantly smaller than that using SDCBs;the maximum contact forces drop about 15%—27% compared with the contact forces using SDCBs.Finally,the test bench for the rotor drop experiments is built and the rotor drop experiments for different types of CBs are carried out.Labview data acquisition system is utilized to collect the displacement of rotor and the rotating frequencies of both inner race and intermediate races after rotor drop.The experimental results are comparatively analyzed,and the conclusion that DDCB can help to reduce vibration amplitude and collision force is obtained.The studies can provide certain theoretical and experimental references for the application of DDCBs in AMB system.展开更多
Objective:With the increasing use of a peripherally inserted central catheter(PICC)in clinical application,the breaking of the PICC is increasing as well,which would turn into the emboli and drift to the heart and pul...Objective:With the increasing use of a peripherally inserted central catheter(PICC)in clinical application,the breaking of the PICC is increasing as well,which would turn into the emboli and drift to the heart and pulmonary artery,causing severe consequences.However,few cases have been reported on the rescue of patients with a broken PICC.Patient concerns:A 33-year-old man,diagnosed with chronic hepatitis B-related decompensated cirrhosis and cryptococcal meningitis,was treated with amphotericin B combined with flucytosine and fluconazole by means of PICC catheterization.The patient was discharged with a catheter;when he returned for re-examination,a 50cm length of PICC broke and slipped into the vein after his sudden dysphoria.First aid was immediately administered,and then the intervention therapy to extricate the tube,including pulmonary artery angiography and intravascular removal of foreign matter,was performed based on the consensus of the in-hospital vein treatment group.At last,the broken PICC fragment was successfully taken out of the vessel.Re-examination after surgery showed that he recovered well.Conclusions:Once the catheter is broken,the X-ray examination should be performed at the first instance and re-examined frequently.Moreover,the involvement of a multidisciplinary team should be formed to decide the appropriate method of treatment to ensure a successful rescue.展开更多
The Catcher in the Rye,J.D. Salinger's first long fiction,was one of his most famous and successful works. It not only influenced American novels written afterwards,for example,Evan Hunter's Last Summer,Sylvia...The Catcher in the Rye,J.D. Salinger's first long fiction,was one of his most famous and successful works. It not only influenced American novels written afterwards,for example,Evan Hunter's Last Summer,Sylvia Plath's The Bell Jar,but also influenced the American society. Take the American film industry which was so good at chasing the audience's interest for a typical example:a large numebr of movies,such as Rebel Without A Cause,American Graffiti,Dirty Dancing,The graduate,and so on:they wouldn't have been filmed like that if The Catcher in the Rye didn't go front as a model. Then,can we really find any big differences between the anxiety ex-pressed by Holden and that by the music and words of Jewel,the Green Day,and the Smashing Pumpkins?展开更多
By releasing the book The Catcher in the Rye,J.D.Salinger received an immediate popularity of his writing career.Hissymbolic use of language has been thoroughly researched but the symbolic scenes which make up Holden&...By releasing the book The Catcher in the Rye,J.D.Salinger received an immediate popularity of his writing career.Hissymbolic use of language has been thoroughly researched but the symbolic scenes which make up Holden's life stage,especiallythe symbolic connotations of ironic resting places in the novel,such as bed,couch and bedroom,has not been paid much attention.It tries to analyse the four scenes: on Holden's history teacher's bed,on the hotel bed with a prostitute,in his sister's bedroom,and on his English teacher's couch,and aims to discover his spiritual chaos as well as adolescent desires in the real world,demon-strating that there is no place for adolescent Holden to rest after he chooses his own stage of scenes in his life.展开更多
Sand production often leads to the failure of production equipment on offshore platform.Therefore,a new idea has been put forward,which is installing cyclone or baffle in the internal of the slug catcher for better sa...Sand production often leads to the failure of production equipment on offshore platform.Therefore,a new idea has been put forward,which is installing cyclone or baffle in the internal of the slug catcher for better sand control.In this paper,an experimental study is presented,which mainly includes sand particles accumulation shape,migration law and separation performance.The results suggest that the accumulation area is mainly divided into two zones:the crowded settlement zone and the free settlement zone.The crowded settlement zone has a special shape,which can be characterized by two parameters:accumulation length and accumulation angle.Axial sampling analysis shows obvious particle classification.Median particle size decreases with the increase of the axial distance,and the range of particle size distribution narrows gradually.The separation experiment shows that the gas velocity has the greatest influence on the separation efficiency.When the gas velocity is 14 m·s^ 1,the separation efficiency drops sharply,which can be abated by installing cyclone separator.In addition,the separation efficiency tends to be a constant under different gas velocities by installing baffle with appropriate height.Then the effectiveness and rationality of installing internal components can be strongly proved.All these provide important guidance for maximizing the sand control function of the slug catcher.展开更多
The Catcher in the Rye has been popular with readers since its publication,and critics at home and abroad have also conducted a lot of research on it.But they mainly proceed from the author and the text to evaluate an...The Catcher in the Rye has been popular with readers since its publication,and critics at home and abroad have also conducted a lot of research on it.But they mainly proceed from the author and the text to evaluate and analyze,ignoring the readers who are essential participants in text interpretation in the eyes of reader-response critics.In order to make up for this shortcoming,this article will take Iser’s reader-response criticism as a research perspective,starting from the three aspects of implied reader,response-inviting structure,and gaps to explore the interaction between the text of The Catcher in the Rye and the readers during the reading process.This research is expected to provide a new interpretation of this novel and provide reference for future research in related fields.展开更多
Lonely Holden in the Catcher in the Rye wanders in New York for three days after he leaves school and he feels even lonelier. What he sees and meets stimulates his criticism and protest.
Steam explosion is one of the crucial and poorly understood phenomena which may occur during severe accident scenario and may lead to containment failure. In spite of several experimental and analytical studies, the r...Steam explosion is one of the crucial and poorly understood phenomena which may occur during severe accident scenario and may lead to containment failure. In spite of several experimental and analytical studies, the root cause of steam explosion has not been understood. Recent claims in the literature suggest that the presence of fine fragmentation during steam explosion causes its occurrence. In order to investigate this and understand the root cause of steam explosion, series of experiments were performed with 50 g to 2500 g of CaO-B<sub>2</sub>O<sub>3</sub>, a corium simulant in 4.5 litre of water. It was observed that steam explosion may occur even in the absence of fine fragments, which is contrary to the claims in the literature. To investigate further, conversion efficiency analysis was performed. This suggested that the amount of thermal energy converted to mechanical energy is more important deciding factor in explaining the occurrence of steam explosion. The present study discusses the importance of conversion efficiency in deciding steam explosion and also gives a new perspective to look at steam explosion phenomenology.展开更多
This paper analyzes the E-C translation of the book The Catcher in the Rye from the perspective of Skopos theory,taking Sun Zhongxu's translation work as an example,in which,literature method and case study method...This paper analyzes the E-C translation of the book The Catcher in the Rye from the perspective of Skopos theory,taking Sun Zhongxu's translation work as an example,in which,literature method and case study method are adopted.The paper finds that Sun Zhongxu uses many colloquial expressions to convey the meaning of the source language.His translation strategies,his translation of American slangs,and his choices of words all reflect the three rules of Skopos theory.展开更多
文摘At the end of September, banners carrying the slogan "Catch one thief, get 1,000yuan" appeared in Gulou District of Fuzhou,capital of southeast China’s Fujian Province.According to local officials, the goal of
基金This research was supported by the National Natural Science Foundation of China(Grant No.51778511)the European Commission H2020 Marie S Curie Research and Innovation Staff Exchange(RISE)award(Grant No.871998)+2 种基金Hubei Provincial Natural Science Foundation of China(Grant No.2018CFA029)Key Project of ESI Discipline Development of Wuhan University of Technology(Grant No.2017001)the Fundamental Research Funds for the Central Universities(Grant No.2019IVB082).
文摘The microenvironment,which involves pollutant dispersion of the urban street canyon,is critical to the health of pedestrians and residents.The objectives of this work are twofold:(i)to effectively assess the pollutant dispersion process based on a theory and(ii)to adopt an appropriate stratigy,i.e.,wind catcher,to alleviate the pollution in the street canyons.Pollutant dispersion in street canyons is essentially a convective mass transfer process.Because the convective heat transfer process and the mass transfer process are physically similar and the applicability of field synergy theory to turbulence has been verified in the literature,we apply the field synergy theory to the study of pollutant dispersion in street canyons.In this paper,a computational fluid dynamics(CFD)simulation is conducted to investigate the effects of wind catcher,wind speed and the geometry of the street canyons on pollutant dispersion.According to the field synergy theory,Sherwood number and field synergy number are used to quantitatively evaluate the wind catcher and wind speed on the diffusion of pollutants in asymmetric street canyons.The results show that adding wind catchers can significantly improve the air quality of the step-down street canyon and reduce the average pollutant concentrations in the street canyon by 75%.Higher wind speed enhances diffusion of pollutants differently in different geometric street canyons.
基金supported by National Natural Science Foundation of China (Grant No. 50975134)
文摘In an active magnetic bearing (AMB) system, the catcher bearings (CBs) are indispensable to protect the rotor and stator in case the magnetic bearings fail. Most of the former researches associated with CBs are mainly focused on the dynamic responses of the rotor drops onto traditional single-decker catcher bearings (SDCBs). But because of the lower limited speed of SDCB, it cannot withstand the ultra high speed rotation after rotor drop. In this paper, based on the analysis of the disadvantages of SDCBs, a new type of double-decker catcher bearings (DDCBs) is proposed to enhance the CB work performance in AMB system. In order to obtain thc accurate rotor movements before AMB failure, the dynamic characteristics of AMB are theoretically derived. Detailed simulation models containing rigid rotor model, contact model between rotor and inner race, DDCB force model as well as heating model after rotor drop are established. Then, using those established models the dynamic responses of rotor drops onto DDCBs and SDCBs are respectively simulated. The rotor orbits, contact forces, spin speeds of various parts and heat energies after AMB failure are mainly analyzed. The simulation results show that DDCBs can effectively improve the CBs limit rotational speed and reduce the following vibrations, impacts and heating. Finally, rotor drop experiments choosing different types of CBs are carried out on the established AMB test bench. Rotor orbits, inner race temperatures as well as the rotating speeds of both inner race and intermediate races after rotor drop are synchronously measured. The experiment results verify the advantages of DDCB and the correctness of theoretical analysis. The studies provide certain theoretical and experimental references for the application of DDCBs in AMB system.
文摘To mitigate consequences of core melting,an ex-vessel core catcher is investigated in this study.Instructions should be obeyed to cool down the corium caused by core melting.The corium destroys the reactor containment and causes radioactive materials to be released into the environment if it does not cool down well.It is important to build a core catcher system for the reception,localization,and cool down of the molten corium during a severe accident resulting from core melting.In this study,the role of a core catcher in the VVER-1000/v528 reactor containment during a station black out(SBO)accident is evaluated using the MELCOR1.8.6 code.In addition,parametric analyses of the SBO for(i)SBO accidents with emergency core cooling system(ECCS)operation,and(ii)without ECCS operation are performed.Furthermore,thermal–hydraulic analyses in dry and wet cavities with/without water are conducted.The investigations include the reduction of gases resulting from molten–corium–concrete interactions(H_(2),CO,CO_(2)).Core melting,gas production,and the pressure/temperature in the reactor containment are assessed.Additionally,a full investigation pertaining to gas release(H_(2),CO,CO_(2))and the pressure/temperature of the core catcher is performed.Based on MELCOR simulations,a core cavity and a perimeter water channel are the best options for corium cooling and a lower radionuclide release.This simulation is also theoretically investigated and discussed herein.The simulation results show that the core catcher system in addition to an internal sacrificial material reduces the containment pressure from 689 to 580 kPa and the corresponding temperature from 394 to 380 K.Furthermore,it is observed that the amount of gases produced,particularly hydrogen,decreased from 1698 to 1235 kg.Moreover,the presence of supporting systems,including an ECCS with a core catcher,prolonged the core melting time from 16,430 to 28,630 s(in an SBO accident)and significantly decreased the gases produced.
基金Supported by the National Natural Science Foundation of China(51205186)the National Science Foundation for Post-doctoral Scientists of China(2012M511264)the Specialized Research Fund for the Doctoral Program of Higher Education of China(20123218120024)
文摘In an active magnetic bearing(AMB)system,the catcher bearings(CBs)are indispensable to protect the rotor and stator in case the magnetic bearings fail or overload.A new CB structure composed of two ball bearings is introduced.Detailed simulation models containing contact model between rotor and inner race,double-decker catcher bearing(DDCB)model as well as single-decker catcher bearing(SDCB)model are established using multibody dynamics simulation software MSC.ADAMS.Then,using those established models,the rotor orbits and the contact forces between rotor and inner race are simulated respectively after rotor drop on DDCBs and SDCBs.The simulation result shows that the rotor vibration range using DDCBs is significantly smaller than that using SDCBs;the maximum contact forces drop about 15%—27% compared with the contact forces using SDCBs.Finally,the test bench for the rotor drop experiments is built and the rotor drop experiments for different types of CBs are carried out.Labview data acquisition system is utilized to collect the displacement of rotor and the rotating frequencies of both inner race and intermediate races after rotor drop.The experimental results are comparatively analyzed,and the conclusion that DDCB can help to reduce vibration amplitude and collision force is obtained.The studies can provide certain theoretical and experimental references for the application of DDCBs in AMB system.
文摘Objective:With the increasing use of a peripherally inserted central catheter(PICC)in clinical application,the breaking of the PICC is increasing as well,which would turn into the emboli and drift to the heart and pulmonary artery,causing severe consequences.However,few cases have been reported on the rescue of patients with a broken PICC.Patient concerns:A 33-year-old man,diagnosed with chronic hepatitis B-related decompensated cirrhosis and cryptococcal meningitis,was treated with amphotericin B combined with flucytosine and fluconazole by means of PICC catheterization.The patient was discharged with a catheter;when he returned for re-examination,a 50cm length of PICC broke and slipped into the vein after his sudden dysphoria.First aid was immediately administered,and then the intervention therapy to extricate the tube,including pulmonary artery angiography and intravascular removal of foreign matter,was performed based on the consensus of the in-hospital vein treatment group.At last,the broken PICC fragment was successfully taken out of the vessel.Re-examination after surgery showed that he recovered well.Conclusions:Once the catheter is broken,the X-ray examination should be performed at the first instance and re-examined frequently.Moreover,the involvement of a multidisciplinary team should be formed to decide the appropriate method of treatment to ensure a successful rescue.
文摘The Catcher in the Rye,J.D. Salinger's first long fiction,was one of his most famous and successful works. It not only influenced American novels written afterwards,for example,Evan Hunter's Last Summer,Sylvia Plath's The Bell Jar,but also influenced the American society. Take the American film industry which was so good at chasing the audience's interest for a typical example:a large numebr of movies,such as Rebel Without A Cause,American Graffiti,Dirty Dancing,The graduate,and so on:they wouldn't have been filmed like that if The Catcher in the Rye didn't go front as a model. Then,can we really find any big differences between the anxiety ex-pressed by Holden and that by the music and words of Jewel,the Green Day,and the Smashing Pumpkins?
文摘By releasing the book The Catcher in the Rye,J.D.Salinger received an immediate popularity of his writing career.Hissymbolic use of language has been thoroughly researched but the symbolic scenes which make up Holden's life stage,especiallythe symbolic connotations of ironic resting places in the novel,such as bed,couch and bedroom,has not been paid much attention.It tries to analyse the four scenes: on Holden's history teacher's bed,on the hotel bed with a prostitute,in his sister's bedroom,and on his English teacher's couch,and aims to discover his spiritual chaos as well as adolescent desires in the real world,demon-strating that there is no place for adolescent Holden to rest after he chooses his own stage of scenes in his life.
文摘Sand production often leads to the failure of production equipment on offshore platform.Therefore,a new idea has been put forward,which is installing cyclone or baffle in the internal of the slug catcher for better sand control.In this paper,an experimental study is presented,which mainly includes sand particles accumulation shape,migration law and separation performance.The results suggest that the accumulation area is mainly divided into two zones:the crowded settlement zone and the free settlement zone.The crowded settlement zone has a special shape,which can be characterized by two parameters:accumulation length and accumulation angle.Axial sampling analysis shows obvious particle classification.Median particle size decreases with the increase of the axial distance,and the range of particle size distribution narrows gradually.The separation experiment shows that the gas velocity has the greatest influence on the separation efficiency.When the gas velocity is 14 m·s^ 1,the separation efficiency drops sharply,which can be abated by installing cyclone separator.In addition,the separation efficiency tends to be a constant under different gas velocities by installing baffle with appropriate height.Then the effectiveness and rationality of installing internal components can be strongly proved.All these provide important guidance for maximizing the sand control function of the slug catcher.
文摘The Catcher in the Rye has been popular with readers since its publication,and critics at home and abroad have also conducted a lot of research on it.But they mainly proceed from the author and the text to evaluate and analyze,ignoring the readers who are essential participants in text interpretation in the eyes of reader-response critics.In order to make up for this shortcoming,this article will take Iser’s reader-response criticism as a research perspective,starting from the three aspects of implied reader,response-inviting structure,and gaps to explore the interaction between the text of The Catcher in the Rye and the readers during the reading process.This research is expected to provide a new interpretation of this novel and provide reference for future research in related fields.
文摘Lonely Holden in the Catcher in the Rye wanders in New York for three days after he leaves school and he feels even lonelier. What he sees and meets stimulates his criticism and protest.
文摘Steam explosion is one of the crucial and poorly understood phenomena which may occur during severe accident scenario and may lead to containment failure. In spite of several experimental and analytical studies, the root cause of steam explosion has not been understood. Recent claims in the literature suggest that the presence of fine fragmentation during steam explosion causes its occurrence. In order to investigate this and understand the root cause of steam explosion, series of experiments were performed with 50 g to 2500 g of CaO-B<sub>2</sub>O<sub>3</sub>, a corium simulant in 4.5 litre of water. It was observed that steam explosion may occur even in the absence of fine fragments, which is contrary to the claims in the literature. To investigate further, conversion efficiency analysis was performed. This suggested that the amount of thermal energy converted to mechanical energy is more important deciding factor in explaining the occurrence of steam explosion. The present study discusses the importance of conversion efficiency in deciding steam explosion and also gives a new perspective to look at steam explosion phenomenology.
文摘This paper analyzes the E-C translation of the book The Catcher in the Rye from the perspective of Skopos theory,taking Sun Zhongxu's translation work as an example,in which,literature method and case study method are adopted.The paper finds that Sun Zhongxu uses many colloquial expressions to convey the meaning of the source language.His translation strategies,his translation of American slangs,and his choices of words all reflect the three rules of Skopos theory.