Zirconium-titanium-steel composite plate with the size of 2500 mm×7800 mm×(3+0.7+22)mm was prepared by explosive welding+rolling method,and its properties were analyzed by ultrasonic nondestructive testing,p...Zirconium-titanium-steel composite plate with the size of 2500 mm×7800 mm×(3+0.7+22)mm was prepared by explosive welding+rolling method,and its properties were analyzed by ultrasonic nondestructive testing,phased array waveform shape,interface structure shape,electronic scanning,and mechanical property testing.Results show that the rolling temperature of zirconiumtitanium complex should be controlled at 760°C,and the rolling reduction of each pass should be controlled at 10%–25%.The explosive velocity to prepare zirconium-titanium-steel composite plates should be controlled at 2450–2500 m/s,the density should be 0.78 g/cm3,the stand-off height should be 12 mm,and the explosive height of Zone A and Zone B should be 45–50 mm.Explosive welding combined with rolling method reduces the impact of explosive welding and multiple heat treatment on material properties.Meanwhile,the problems of surface wrinkling and cracking,which occur during the preparation process of large-sized zirconiumtitanium-steel composite plate,can be solved.展开更多
The seamless trailing edge morphing flap is investigated using a high-fidelity steady-state aerodynamic shape optimization to determine its optimum configuration for different flight conditions,including climb,cruise,...The seamless trailing edge morphing flap is investigated using a high-fidelity steady-state aerodynamic shape optimization to determine its optimum configuration for different flight conditions,including climb,cruise,and gliding descent.A comparative study is also conducted between a wing equipped with morphing flap and a wing with conventional hinged flap.The optimization is performed by specifying a certain objective function and the flight performance goal for each flight condition.Increasing the climb rate,extending the flight range and endurance in cruise,and decreasing the descend rate,are the flight performance goals covered in this study.Various optimum configurations were found for the morphing wing by determining the optimum morphing flap deflection for each flight condition,based on its objective function,each of which performed better than that of the baseline wing.It was shown that by using optimum configuration for the morphing wing in climb condition,the required power could be reduced by up to 3.8%and climb rate increases by 6.13%.The comparative study also revealed that the morphing wing enhances aerodynamic efficiency by up to 17.8%and extends the laminar flow.Finally,the optimum configuration for the gliding descent brought about a 43%reduction in the descent rate.展开更多
With the development of modern information technology and network society,the era of digital transformation has arrived,many educational resources have been developed and utilized,and the problem of space-time separat...With the development of modern information technology and network society,the era of digital transformation has arrived,many educational resources have been developed and utilized,and the problem of space-time separation of global Chinese learners is gradually being solved.The use of mobile application learning can achieve convenient and fast learning,reduce learning costs,and flexibly adjust learning progress.After experiencing COVID-19,the demand for human-computer interaction in mobile learning is even more necessary.Therefore,to make applications achieve seamless docking with the needs of learners in the design of learning,the research investigates and analyzes the five dimensions of time,space,mode,subject,and object.The research tests the reliability and validity of the questionnaire,removes the relevant items and conducts non-parametric tests,then puts forward corresponding strategies according to the results of the questionnaire.It aims to enhance the efficiency of Chinese learners in HSK(Hanyu Shuiping Kaoshi,Chinese Proficiency Test)learning and promote Chinese learning and the spread of the Chinese language and culture.展开更多
The complex effects of different nitrogen （N） contents and thermal routines on the microstructure and mechanical properties of 33Mn2V steels for N80-Class seamless casing tube application were investigated using Gle...The complex effects of different nitrogen （N） contents and thermal routines on the microstructure and mechanical properties of 33Mn2V steels for N80-Class seamless casing tube application were investigated using Gleeble simulation technique. The results showed that the N additions of 0. 014 %- 0. 021 % in the steels for the in-line normalization process （ILNP） increased the strength while the toughngss remained at a high level as compared with the steel with N content of 0. 005 %. It was also revealed that the N addition of 0. 021%could enhance the performance combination of strength and toughness in the steels by using 700 ℃ as the cooling interrupted temperature （CIT） for the non in-line normalizing process （NILNP）. It was further evidenced that the toughness was improved at expense of strength to some degree in all the steels by decreasing reheating temperature for the ILNP, while an increase of CIT for NILNP severely impaired the toughness and slightly improve the strength in the high-N steel with N content of 0. 021%. This can be attributed to the dissolution and precipitation behavior of V（C,N）. The optimization of V （C,N） precipitation could be achieved by enhancing N. The precipitation of V（C, N） in austenite was promoted by cooling to a certain temperature lower than the A,1 for the ILNP. The V（C,N） particles formed in austenite contrib- uted to grain refinement by the VN-induced nucleation of intragranular ferrite, but as a result the effect of precipitation on strengthening would become weaker due to a decrease of the precipitation of V in ferrite.展开更多
A 25CrMo48V steel for ultra-deep oil/gas well casings was quenched at 900-1 200 ℃ and tempered at 650 ℃. The lath martensitic structures were characterized by optical microscope （OM）, field emission scanning elect...A 25CrMo48V steel for ultra-deep oil/gas well casings was quenched at 900-1 200 ℃ and tempered at 650 ℃. The lath martensitic structures were characterized by optical microscope （OM）, field emission scanning electron microscopy （FESEM）, electron backscattering diffraction （EBSD） and transmission electron microscopy （TEM）, and the transverse impact energy at 0 ℃ was measured from the as-quenched and tempered specimens. The results show that with the quenching temperature decreased, the prior austenite grain, martensitic packet and block are refined, while the lath width seems to remain unchanged. The enhancement of impact toughness with the decreasing quenching temperature can be attributed to refinement of the martensitic structure with high-angle boundaries, and the block is the minimum structure unit controlling impact toughness. The transverse impact energy [ECVN （0 ℃） ≥100 J] required for seamless casings with ultra-high strength （Rp0.2≥932 MPa） has been finally achieved with the experimental steel quenched at 900-1 000 ℃ and tempered at 650 ℃.展开更多
Purpose:To evaluate the efficacy of the Seamless Transfer of Care Model(STCM)to improve readmission occurrence of patients withstroke.Methods:The sample was comprised of fifty-nine subjects with stroke who were hospit...Purpose:To evaluate the efficacy of the Seamless Transfer of Care Model(STCM)to improve readmission occurrence of patients withstroke.Methods:The sample was comprised of fifty-nine subjects with stroke who were hospitalized in the geriatric and neurology departments of a large university hospital in China.Subjects were allocated to an STCM group(n=30)or a routine care(control)group(n=29).Results:Compared with the control group,the STCM group had a higher quality of life(p<0.05),higher compliance(p<0.05)and a lower readmission rate(p<0.05).Conclusion:Based on our results,the application of the STCM in Chinese stroke patients can improve quality of life and compliance,and reduce readmission rate.展开更多
The tube rotation method （TRM） refers to the rotational movement of steel tube about its axis as well as translation in rolling direction in stretch reducing rolling process. The influence of the TRM on transverse w...The tube rotation method （TRM） refers to the rotational movement of steel tube about its axis as well as translation in rolling direction in stretch reducing rolling process. The influence of the TRM on transverse wall thickness precision of seamless steel tube was studied. Thickness distribution of the TRM was obtained by superimposing the thickened amount of single pass rolling. Results show that the TRM can effectively improve the evenness of thickness distribution. In order to analyze the influence mechanism of the TRM, the finite element method was adopted to simulate the thickness distribution in stretch reduction process. Results show that the TRM changes the roundtrip flow between two fix places of conventional stretch reducing and inhibits the directional accumulation of metal. In addition, the TRM has a correction effect on thickness cusp. All these advantages of the TRM help to improve the transverse wall thickness precision of seamless steel tube.展开更多
Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simp...Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simple applications without giving stakeholders the chance to play an active role.Our specific aim is to solve these issues.This paper presents concepts to solve these issues by expanding the Open Location Services Interface Standard (OpenLS) to allow seamless indoor/outdoor positioning and to extend the content of the services to include information recommended by stakeholders.展开更多
Seamless prediction is a weather-climate integrated prediction covering multiple time scales that include days,weeks,months,seasons,years,and decades.Seamless prediction can provide different industries with informati...Seamless prediction is a weather-climate integrated prediction covering multiple time scales that include days,weeks,months,seasons,years,and decades.Seamless prediction can provide different industries with information such as weather conditions and climate variations from the next few days to years,which have important impacts on economic and social development and important reference value for short-,medium-and long-term decision-making and planning of the country.Therefore,seamless prediction has received widespread attention from the international scientific community recently.As Chinese scientists have also carried out relevant research,this paper reviews the research in China on developments and applications of seamless prediction methods and prediction systems in recent years.Among them,the main progress of seamless prediction methods studies is reviewed from four aspects:short-and medium-range weather forecasting,subseasonal-to-seasonal,seasonal-to-interannual,and decadal climate prediction.In terms of development and application of seamless prediction systems,the main achievements made by meteorological operational departments,scientific institutes,and universities in China in recent years are reviewed.Finally,some of the issues in seamless prediction that need further study are discussed.展开更多
This paper presents a seamless transmission technique for Non-Geostationary Earth Orbit(NGEO) satellite networks.The seamless transmission technique combines the concept of Hop-by-Hop and network coding to alleviate t...This paper presents a seamless transmission technique for Non-Geostationary Earth Orbit(NGEO) satellite networks.The seamless transmission technique combines the concept of Hop-by-Hop and network coding to alleviate the negative impacts of handovers,high bit error rate,and long delay,and to achieve high throughput and complete delivery in NGEO satellite networks.This network coding algorithm is able to maintain expected small queue size and low decoding latency.Furthermore,the seamless transmission technique applies a novel explicit congestion notification mechanism and can achieve high bandwidth utilization.Various aspects of this seamless transmission technique are evaluated.展开更多
The relationship between microstructures and mechanical properties of a medium carbon V-N microalloyed steel used for N80 seamless oil-well tubes of hot rolling non-quenched/tempered (non-Q and T) was investigated.The...The relationship between microstructures and mechanical properties of a medium carbon V-N microalloyed steel used for N80 seamless oil-well tubes of hot rolling non-quenched/tempered (non-Q and T) was investigated.The results have shown that volume percentages of upper bainite,modified bainite and ferrite have a decisive influence on impact energies of steel tubes.When the total volume percentage of bainite is larger than 5%,the impact energy of tubes can not satisfy with the industrial criteria.Moreover,if the total volume percentage of bainite is smaller than 5%,then the impact energy of steel tubes enhances with volume percentage of ferrite increasing.The final microstructures have closely relation with tube billet quality,controlled cooling temperature after tube rolling and cooling method after stretch-reduction-diameter.High quality of medium carbon V-N microalloyed steel for non-Q and T oil-well tubes can be produced through comprehensive control of microstructures and mechanical properties in sub-procedures,especially for tube billet quality and controlled cooling parameters.展开更多
This paper studies the voltage, phase and current tracking strategy to eliminate voltage and current mutations when the virtual synchronous generator is switching between grid-connected and islanded. By using these st...This paper studies the voltage, phase and current tracking strategy to eliminate voltage and current mutations when the virtual synchronous generator is switching between grid-connected and islanded. By using these strategies the inverter can realize secondary frequency regulation and voltage regulation. If the phase is near 0 or 2π a little disturbance may made the PLL output a big error, so a new PLL is proposed by this paper. A sine module is added in the PLL to avoid this error. In order to verify the strategy proposed by this paper a simulation model is built in Matlab/Simulink. The simulation results show that the control strategy can realize seamless switching.展开更多
The seamless tiled display is an effective realization for the wide field and high-resolution display of media;the technology of edge blending is the core of seamless tiled display system and is also the hot-spot of D...The seamless tiled display is an effective realization for the wide field and high-resolution display of media;the technology of edge blending is the core of seamless tiled display system and is also the hot-spot of Digital Light Process (DLP). The paper introduces the technique of edge blending process and puts forward the improved algorithm of edge blending in order to eliminate the edge of the light generated regional integration and achieve seamless connection. The algorithm is the modification of existing fusion algorithm that using two addition parameters p and a, and finally adds Gamma operator to further correction of the pixel brightness. Experimental results show that, the proposed algorithm effectively eliminates the light generated by the edge of the integration region and the image has good transitions, the proposed algorithm reduces the output of the projector color differences by the value of SNR.展开更多
Taking the seamless tube plant of Baoshan Iron & Steel Complex in China as the background,we analyze the characters of hot rolling seamless steel tube:multi varieties,low volume,complicated production process,flex...Taking the seamless tube plant of Baoshan Iron & Steel Complex in China as the background,we analyze the characters of hot rolling seamless steel tube:multi varieties,low volume,complicated production process,flexible production routes.Then integrated scheduling problem for hot rolling seamless steel tube production is studied,which covers two key points;order-grouping problem and solution method for flowshop/jobshop scheduling problem.On the basis of these two problems,integrated scheduling decision system is developed.The design idea,function flow sheet,data processing method,and functional module of visualized human-computer interactive scheduling system implemented in seamless steel tube plant of Shanghai Baoshan Iron & Steel Complex are described into detail.Compared with manual system,the performance of system shows the applicability and superiority in several criteria.展开更多
With the widespread application and fast development of gas and oil pipeline network in China, the pipeline inspection technology has been used more extensively. The magnetic flux leakage （MFL） method has establishe...With the widespread application and fast development of gas and oil pipeline network in China, the pipeline inspection technology has been used more extensively. The magnetic flux leakage （MFL） method has established itself as the most widely used in-line inspection technique for the evaluation of gas and oil pipelines. The MFL data obtained from seamless pipeline inspection is usually contaminated by the seamless pipe noise （SPN）. SPN can in some cases completely mask MFL signals from certain type of defects, and therefore considerably reduces the detectability of the defect signals. In this paper, a new de-noising algorithm called wavelet domain adaptive filtering is proposed for removing the SPN contained in the MFL data. The new algorithm results from combining the wavelet transform with the adaptive filtering technique. Results from application of the proposed algorithm to the MFL data from field tests show that the proposed algorithm has good performance and considerably improves the detectability of the defect signals in the MFL data.展开更多
A low-carbon TRIP seamless steel tube, which is expected to be used in the hydroforming process, was successfully fabricated using piercing, cold-drawing and two-stage heat treatment process. The two-stage heat treatm...A low-carbon TRIP seamless steel tube, which is expected to be used in the hydroforming process, was successfully fabricated using piercing, cold-drawing and two-stage heat treatment process. The two-stage heat treatment is one crucial step because it significantly affects the microstructure and mechanical properties of TRIP seam less steel tube. In order to obtain the TRIP seamless steel tube with high hydroformability, several different heat treatment processes were conducted. The effects of heat treatment conditions （intercritical annealing （IA） and isothermal bainite treatment （IBT）） on the TRIP seamless steel tube hydroformability which was determined by free hydraulic bulge test were analyzed. Two different internal pressure boosting velocities of 0.2 and 0.5 MPa/s of free hydraulic bulge tests were adopted to determine the effective stress vs. effective strain curve of TRIP seamless steel tube. The results showed that for the predetermined IA condition, the maximum bulge height increased, but the maximum burst internal pressure decreased, with the increase of IBT holding time from 4 to 6 rain. For the predetermined IBT condition, the maximum bulge height decreased, but the maximum burst internal pressure increased, with the increase of IA holding time from 5 to 10 rain. By analyzing the free hydraulic bulge test results, it was found that the maximum bulge heights of TRIP seamless steel tubes with the internal pressure boosting velocity of 0.5 MPa/s were higher than those when the internal pressure boosting velocity was 0.2 MPa/s. This means that an appropriate deformation rate should be chosen to obtain the optimal hydroformability of TRIP seamless steel tube. In addition, the effective stress vs. effective strain curves of TRIP seamless steel tubes were ohtained with free hydraulic bulge test.展开更多
The mechanical properties of the steel pipe rolled with continuously casting round billet after determining the chemical composition in steel were studied.The results show that the total reduction ratio should be high...The mechanical properties of the steel pipe rolled with continuously casting round billet after determining the chemical composition in steel were studied.The results show that the total reduction ratio should be higher than 5.2 when the line pipes of grade B,grade 20 and other general seamless pipe were rolled with continuously casting round billet.And the total reduction ratio should be higher than 10.2 and the grain size should be controlled more than grade 7 for casing of oil countryside tubular goods(OCTG).展开更多
The Aging Tsunami as it is often quoted to describe the worrying situations of rapidly aging in China has not met with detail planning in facilities upgrade and careful consideration in service models. Broad brushed c...The Aging Tsunami as it is often quoted to describe the worrying situations of rapidly aging in China has not met with detail planning in facilities upgrade and careful consideration in service models. Broad brushed central policies categorizes services into home care, community care and institutional care and set policy goals at 90-6-4, representing the percentage of older people in receiving respective care. This leaves local officials helpless on how these ideals can be actualized. Some cities have inclined to build huge older people homes and pour resources into institutional care, forgetting the need for older people to be connected with the society. This paper reviews the historical developments of older people services in Hong Kong and recommends an integrative model of social work services connecting institutional, community and home care into a seamless network. The city of Zhuhai will be presented as a perfect experimental city on how its existing facilities can be converted and developed according to the model. Survey on the situations of the 16 public older people homes will be used to illustrate the potentials of an integrative model.展开更多
According to the characteristics of PQF continuous rolling pass,the relationship between spread coefficient,wall thickness coefficient and elongation are analyzed.The section shape of tube in each stand outlet,the eff...According to the characteristics of PQF continuous rolling pass,the relationship between spread coefficient,wall thickness coefficient and elongation are analyzed.The section shape of tube in each stand outlet,the efficient working radius and the rotational speed of each roll are obtained,therefore,the pass parametric design is completed.A thermal-mechanical coupled model of continuous rolling tube' s forming process is established by the three-dimensional elasto-plastic finite element method,the section shape and area of tube in each stand outlet are forecasted,which is used to modify the pass.The rolling force of each roller is predict too,which provides a guidance for pass design.In addition,a visual software of PQF pass parametric design system on heavy calibre seamless tube is generated with Visual Basic.The forming dimension of tube and the rolling force of each roller are successfully obtained,by simulating the forming process of a certain series heavy calibre seamless tube.This system posses practical utilization value.By using this system,the development cycle of new product can be shortened,the reliability of pass design can be improved,and the energy consumption of rolling mill and production cost can be decreased.展开更多
基金Key R&D Plan of Shaanxi Province(2021LLRH-05-09)Shaanxi Province Youth Talent Support Program Project(CLGC202234)Sponsored by Innovative Pilot Platform for Layered Metal Composite Materials(2024CX-GXPT-20)。
文摘Zirconium-titanium-steel composite plate with the size of 2500 mm×7800 mm×(3+0.7+22)mm was prepared by explosive welding+rolling method,and its properties were analyzed by ultrasonic nondestructive testing,phased array waveform shape,interface structure shape,electronic scanning,and mechanical property testing.Results show that the rolling temperature of zirconiumtitanium complex should be controlled at 760°C,and the rolling reduction of each pass should be controlled at 10%–25%.The explosive velocity to prepare zirconium-titanium-steel composite plates should be controlled at 2450–2500 m/s,the density should be 0.78 g/cm3,the stand-off height should be 12 mm,and the explosive height of Zone A and Zone B should be 45–50 mm.Explosive welding combined with rolling method reduces the impact of explosive welding and multiple heat treatment on material properties.Meanwhile,the problems of surface wrinkling and cracking,which occur during the preparation process of large-sized zirconiumtitanium-steel composite plate,can be solved.
基金the Hydra Technologies team in Mexicothe CREATEUTILI Program for their financial support。
文摘The seamless trailing edge morphing flap is investigated using a high-fidelity steady-state aerodynamic shape optimization to determine its optimum configuration for different flight conditions,including climb,cruise,and gliding descent.A comparative study is also conducted between a wing equipped with morphing flap and a wing with conventional hinged flap.The optimization is performed by specifying a certain objective function and the flight performance goal for each flight condition.Increasing the climb rate,extending the flight range and endurance in cruise,and decreasing the descend rate,are the flight performance goals covered in this study.Various optimum configurations were found for the morphing wing by determining the optimum morphing flap deflection for each flight condition,based on its objective function,each of which performed better than that of the baseline wing.It was shown that by using optimum configuration for the morphing wing in climb condition,the required power could be reduced by up to 3.8%and climb rate increases by 6.13%.The comparative study also revealed that the morphing wing enhances aerodynamic efficiency by up to 17.8%and extends the laminar flow.Finally,the optimum configuration for the gliding descent brought about a 43%reduction in the descent rate.
基金2023 International Chinese Teaching Practice Innovation Project(YHJXCX23-039)2024-2025 Higher Education Fund of the Macao SAR Government(MF2342)+2 种基金National Social Science Fund of China(BBA230063)National Social Science Fund of China(BCA200090)Research on the Training Path of Innovative Thinking Ability of College Students in Guangdong(2023GXJK233)。
文摘With the development of modern information technology and network society,the era of digital transformation has arrived,many educational resources have been developed and utilized,and the problem of space-time separation of global Chinese learners is gradually being solved.The use of mobile application learning can achieve convenient and fast learning,reduce learning costs,and flexibly adjust learning progress.After experiencing COVID-19,the demand for human-computer interaction in mobile learning is even more necessary.Therefore,to make applications achieve seamless docking with the needs of learners in the design of learning,the research investigates and analyzes the five dimensions of time,space,mode,subject,and object.The research tests the reliability and validity of the questionnaire,removes the relevant items and conducts non-parametric tests,then puts forward corresponding strategies according to the results of the questionnaire.It aims to enhance the efficiency of Chinese learners in HSK(Hanyu Shuiping Kaoshi,Chinese Proficiency Test)learning and promote Chinese learning and the spread of the Chinese language and culture.
基金Item Sponsored by High-Tech Research and Development Program of China (863 Program) (2007AA03Z506)
文摘The complex effects of different nitrogen （N） contents and thermal routines on the microstructure and mechanical properties of 33Mn2V steels for N80-Class seamless casing tube application were investigated using Gleeble simulation technique. The results showed that the N additions of 0. 014 %- 0. 021 % in the steels for the in-line normalization process （ILNP） increased the strength while the toughngss remained at a high level as compared with the steel with N content of 0. 005 %. It was also revealed that the N addition of 0. 021%could enhance the performance combination of strength and toughness in the steels by using 700 ℃ as the cooling interrupted temperature （CIT） for the non in-line normalizing process （NILNP）. It was further evidenced that the toughness was improved at expense of strength to some degree in all the steels by decreasing reheating temperature for the ILNP, while an increase of CIT for NILNP severely impaired the toughness and slightly improve the strength in the high-N steel with N content of 0. 021%. This can be attributed to the dissolution and precipitation behavior of V（C,N）. The optimization of V （C,N） precipitation could be achieved by enhancing N. The precipitation of V（C, N） in austenite was promoted by cooling to a certain temperature lower than the A,1 for the ILNP. The V（C,N） particles formed in austenite contrib- uted to grain refinement by the VN-induced nucleation of intragranular ferrite, but as a result the effect of precipitation on strengthening would become weaker due to a decrease of the precipitation of V in ferrite.
基金Item Sponsored by National High Technology Research and Development Program of China(2007AA03Z509)National Science Foundation for Distinguished Young Scholars of China(50925522)
文摘A 25CrMo48V steel for ultra-deep oil/gas well casings was quenched at 900-1 200 ℃ and tempered at 650 ℃. The lath martensitic structures were characterized by optical microscope （OM）, field emission scanning electron microscopy （FESEM）, electron backscattering diffraction （EBSD） and transmission electron microscopy （TEM）, and the transverse impact energy at 0 ℃ was measured from the as-quenched and tempered specimens. The results show that with the quenching temperature decreased, the prior austenite grain, martensitic packet and block are refined, while the lath width seems to remain unchanged. The enhancement of impact toughness with the decreasing quenching temperature can be attributed to refinement of the martensitic structure with high-angle boundaries, and the block is the minimum structure unit controlling impact toughness. The transverse impact energy [ECVN （0 ℃） ≥100 J] required for seamless casings with ultra-high strength （Rp0.2≥932 MPa） has been finally achieved with the experimental steel quenched at 900-1 000 ℃ and tempered at 650 ℃.
基金This study was supported by the Research Foundation of Fudan University(FNF201208)Health And Family Planning Commission Of Shanghai(201440090)and Minhang(2012MHZ028).
文摘Purpose:To evaluate the efficacy of the Seamless Transfer of Care Model(STCM)to improve readmission occurrence of patients withstroke.Methods:The sample was comprised of fifty-nine subjects with stroke who were hospitalized in the geriatric and neurology departments of a large university hospital in China.Subjects were allocated to an STCM group(n=30)or a routine care(control)group(n=29).Results:Compared with the control group,the STCM group had a higher quality of life(p<0.05),higher compliance(p<0.05)and a lower readmission rate(p<0.05).Conclusion:Based on our results,the application of the STCM in Chinese stroke patients can improve quality of life and compliance,and reduce readmission rate.
文摘The tube rotation method （TRM） refers to the rotational movement of steel tube about its axis as well as translation in rolling direction in stretch reducing rolling process. The influence of the TRM on transverse wall thickness precision of seamless steel tube was studied. Thickness distribution of the TRM was obtained by superimposing the thickened amount of single pass rolling. Results show that the TRM can effectively improve the evenness of thickness distribution. In order to analyze the influence mechanism of the TRM, the finite element method was adopted to simulate the thickness distribution in stretch reduction process. Results show that the TRM changes the roundtrip flow between two fix places of conventional stretch reducing and inhibits the directional accumulation of metal. In addition, the TRM has a correction effect on thickness cusp. All these advantages of the TRM help to improve the transverse wall thickness precision of seamless steel tube.
文摘Location-Based Services (LBS),an emerging new business based on smartphone and mobile networks,are becoming more and more popular.Most of these LBSs,however,only offer non-seamless indoor/outdoor applications and simple applications without giving stakeholders the chance to play an active role.Our specific aim is to solve these issues.This paper presents concepts to solve these issues by expanding the Open Location Services Interface Standard (OpenLS) to allow seamless indoor/outdoor positioning and to extend the content of the services to include information recommended by stakeholders.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2242206,42175015,and 41975094)the Basic Research and Operational Special Project of CAMS(Grant No.2021Z007).
文摘Seamless prediction is a weather-climate integrated prediction covering multiple time scales that include days,weeks,months,seasons,years,and decades.Seamless prediction can provide different industries with information such as weather conditions and climate variations from the next few days to years,which have important impacts on economic and social development and important reference value for short-,medium-and long-term decision-making and planning of the country.Therefore,seamless prediction has received widespread attention from the international scientific community recently.As Chinese scientists have also carried out relevant research,this paper reviews the research in China on developments and applications of seamless prediction methods and prediction systems in recent years.Among them,the main progress of seamless prediction methods studies is reviewed from four aspects:short-and medium-range weather forecasting,subseasonal-to-seasonal,seasonal-to-interannual,and decadal climate prediction.In terms of development and application of seamless prediction systems,the main achievements made by meteorological operational departments,scientific institutes,and universities in China in recent years are reviewed.Finally,some of the issues in seamless prediction that need further study are discussed.
文摘This paper presents a seamless transmission technique for Non-Geostationary Earth Orbit(NGEO) satellite networks.The seamless transmission technique combines the concept of Hop-by-Hop and network coding to alleviate the negative impacts of handovers,high bit error rate,and long delay,and to achieve high throughput and complete delivery in NGEO satellite networks.This network coding algorithm is able to maintain expected small queue size and low decoding latency.Furthermore,the seamless transmission technique applies a novel explicit congestion notification mechanism and can achieve high bandwidth utilization.Various aspects of this seamless transmission technique are evaluated.
基金financial support from Chinese National Nature Science Fund(Project No.50271009and No.51071019)Wuxi Seamless Steel Tube Company,Ltdthe Vanadium International Technical Committee via the CSM
文摘The relationship between microstructures and mechanical properties of a medium carbon V-N microalloyed steel used for N80 seamless oil-well tubes of hot rolling non-quenched/tempered (non-Q and T) was investigated.The results have shown that volume percentages of upper bainite,modified bainite and ferrite have a decisive influence on impact energies of steel tubes.When the total volume percentage of bainite is larger than 5%,the impact energy of tubes can not satisfy with the industrial criteria.Moreover,if the total volume percentage of bainite is smaller than 5%,then the impact energy of steel tubes enhances with volume percentage of ferrite increasing.The final microstructures have closely relation with tube billet quality,controlled cooling temperature after tube rolling and cooling method after stretch-reduction-diameter.High quality of medium carbon V-N microalloyed steel for non-Q and T oil-well tubes can be produced through comprehensive control of microstructures and mechanical properties in sub-procedures,especially for tube billet quality and controlled cooling parameters.
文摘This paper studies the voltage, phase and current tracking strategy to eliminate voltage and current mutations when the virtual synchronous generator is switching between grid-connected and islanded. By using these strategies the inverter can realize secondary frequency regulation and voltage regulation. If the phase is near 0 or 2π a little disturbance may made the PLL output a big error, so a new PLL is proposed by this paper. A sine module is added in the PLL to avoid this error. In order to verify the strategy proposed by this paper a simulation model is built in Matlab/Simulink. The simulation results show that the control strategy can realize seamless switching.
文摘The seamless tiled display is an effective realization for the wide field and high-resolution display of media;the technology of edge blending is the core of seamless tiled display system and is also the hot-spot of Digital Light Process (DLP). The paper introduces the technique of edge blending process and puts forward the improved algorithm of edge blending in order to eliminate the edge of the light generated regional integration and achieve seamless connection. The algorithm is the modification of existing fusion algorithm that using two addition parameters p and a, and finally adds Gamma operator to further correction of the pixel brightness. Experimental results show that, the proposed algorithm effectively eliminates the light generated by the edge of the integration region and the image has good transitions, the proposed algorithm reduces the output of the projector color differences by the value of SNR.
文摘Taking the seamless tube plant of Baoshan Iron & Steel Complex in China as the background,we analyze the characters of hot rolling seamless steel tube:multi varieties,low volume,complicated production process,flexible production routes.Then integrated scheduling problem for hot rolling seamless steel tube production is studied,which covers two key points;order-grouping problem and solution method for flowshop/jobshop scheduling problem.On the basis of these two problems,integrated scheduling decision system is developed.The design idea,function flow sheet,data processing method,and functional module of visualized human-computer interactive scheduling system implemented in seamless steel tube plant of Shanghai Baoshan Iron & Steel Complex are described into detail.Compared with manual system,the performance of system shows the applicability and superiority in several criteria.
文摘With the widespread application and fast development of gas and oil pipeline network in China, the pipeline inspection technology has been used more extensively. The magnetic flux leakage （MFL） method has established itself as the most widely used in-line inspection technique for the evaluation of gas and oil pipelines. The MFL data obtained from seamless pipeline inspection is usually contaminated by the seamless pipe noise （SPN）. SPN can in some cases completely mask MFL signals from certain type of defects, and therefore considerably reduces the detectability of the defect signals. In this paper, a new de-noising algorithm called wavelet domain adaptive filtering is proposed for removing the SPN contained in the MFL data. The new algorithm results from combining the wavelet transform with the adaptive filtering technique. Results from application of the proposed algorithm to the MFL data from field tests show that the proposed algorithm has good performance and considerably improves the detectability of the defect signals in the MFL data.
基金Item Sponsored by National Natural Science Foundation of China(51304046)Grant-in-Aid for Young Scientists (B) of Japan Society for the Promotion of Science(25870594)+2 种基金Fundamental Research Funds for the Central Universities of China(N130403013)Specialized Research Fund for the Doctoral Program of Higher Education of China(20130042120031)Scientific Research Starting Foundation for Introduced Talents of Northeastern University of China(02090021233002)
文摘A low-carbon TRIP seamless steel tube, which is expected to be used in the hydroforming process, was successfully fabricated using piercing, cold-drawing and two-stage heat treatment process. The two-stage heat treatment is one crucial step because it significantly affects the microstructure and mechanical properties of TRIP seam less steel tube. In order to obtain the TRIP seamless steel tube with high hydroformability, several different heat treatment processes were conducted. The effects of heat treatment conditions （intercritical annealing （IA） and isothermal bainite treatment （IBT）） on the TRIP seamless steel tube hydroformability which was determined by free hydraulic bulge test were analyzed. Two different internal pressure boosting velocities of 0.2 and 0.5 MPa/s of free hydraulic bulge tests were adopted to determine the effective stress vs. effective strain curve of TRIP seamless steel tube. The results showed that for the predetermined IA condition, the maximum bulge height increased, but the maximum burst internal pressure decreased, with the increase of IBT holding time from 4 to 6 rain. For the predetermined IBT condition, the maximum bulge height decreased, but the maximum burst internal pressure increased, with the increase of IA holding time from 5 to 10 rain. By analyzing the free hydraulic bulge test results, it was found that the maximum bulge heights of TRIP seamless steel tubes with the internal pressure boosting velocity of 0.5 MPa/s were higher than those when the internal pressure boosting velocity was 0.2 MPa/s. This means that an appropriate deformation rate should be chosen to obtain the optimal hydroformability of TRIP seamless steel tube. In addition, the effective stress vs. effective strain curves of TRIP seamless steel tubes were ohtained with free hydraulic bulge test.
文摘The mechanical properties of the steel pipe rolled with continuously casting round billet after determining the chemical composition in steel were studied.The results show that the total reduction ratio should be higher than 5.2 when the line pipes of grade B,grade 20 and other general seamless pipe were rolled with continuously casting round billet.And the total reduction ratio should be higher than 10.2 and the grain size should be controlled more than grade 7 for casing of oil countryside tubular goods(OCTG).
文摘The Aging Tsunami as it is often quoted to describe the worrying situations of rapidly aging in China has not met with detail planning in facilities upgrade and careful consideration in service models. Broad brushed central policies categorizes services into home care, community care and institutional care and set policy goals at 90-6-4, representing the percentage of older people in receiving respective care. This leaves local officials helpless on how these ideals can be actualized. Some cities have inclined to build huge older people homes and pour resources into institutional care, forgetting the need for older people to be connected with the society. This paper reviews the historical developments of older people services in Hong Kong and recommends an integrative model of social work services connecting institutional, community and home care into a seamless network. The city of Zhuhai will be presented as a perfect experimental city on how its existing facilities can be converted and developed according to the model. Survey on the situations of the 16 public older people homes will be used to illustrate the potentials of an integrative model.
文摘According to the characteristics of PQF continuous rolling pass,the relationship between spread coefficient,wall thickness coefficient and elongation are analyzed.The section shape of tube in each stand outlet,the efficient working radius and the rotational speed of each roll are obtained,therefore,the pass parametric design is completed.A thermal-mechanical coupled model of continuous rolling tube' s forming process is established by the three-dimensional elasto-plastic finite element method,the section shape and area of tube in each stand outlet are forecasted,which is used to modify the pass.The rolling force of each roller is predict too,which provides a guidance for pass design.In addition,a visual software of PQF pass parametric design system on heavy calibre seamless tube is generated with Visual Basic.The forming dimension of tube and the rolling force of each roller are successfully obtained,by simulating the forming process of a certain series heavy calibre seamless tube.This system posses practical utilization value.By using this system,the development cycle of new product can be shortened,the reliability of pass design can be improved,and the energy consumption of rolling mill and production cost can be decreased.
