The carbides/nitrides precipitates in ferrite grains, on grain boundaries and dislocations were investigated on a hot-rolled C-Mn strip （0.16wt%C-1.22wt%Mn-0.022wt%Ti） produced by the CSP （compact strip production...The carbides/nitrides precipitates in ferrite grains, on grain boundaries and dislocations were investigated on a hot-rolled C-Mn strip （0.16wt%C-1.22wt%Mn-0.022wt%Ti） produced by the CSP （compact strip production） technology using TEM and X-ray energy dispersive spectroscopy. The Pickering＇s equation for the contribution of precipitates to the yield stress was also discussed. It is shown that there are numerous fine and dispersive precipitates TiC in the ferrite grains, on the grain boundaries and dislocations. Also there are a small amount of coarser Ti（C, N） particles and TiC particles associated with MnS. Precipitation strengthening on steels produced by the CSP technology is significant.展开更多
The cultivation of innovative and entrepreneurial capability is a quality requirement of the times for the training of college and university talents. However, the regular teaching system universally has such problems...The cultivation of innovative and entrepreneurial capability is a quality requirement of the times for the training of college and university talents. However, the regular teaching system universally has such problems as much more emphasis on theory than on practice, much more emphasis on inheritance than on innovation, and mismatching between talent training and market demand, so that a great number of graduates do not have enough innovative capacity, and it is very difficult for them to engage in related jobs of software engineering steadily and permanently. By investigating and analyzing similar majors of more than 20 schools at home and abroad, this article proposes a teaching system of talent training of the 3 C-cored major of "innovative and entrepreneurial" software engineering(digital media technology) based on regions, oriented to the industry and marked by school-enterprise linkage, and in connection with the characteristics of college and university education.展开更多
A LM-3C carrier rocket at 0:53 Beijing time on December 25 was launched from the Xichang Satellite Launch Center,putting the Communications Technology Test Satellite 3 into its orbit.The satellite was developed by SAS...A LM-3C carrier rocket at 0:53 Beijing time on December 25 was launched from the Xichang Satellite Launch Center,putting the Communications Technology Test Satellite 3 into its orbit.The satellite was developed by SAST for demonstrating related technologies.展开更多
AIM To investigate the role of bloodtransfusion in TT viral infection(TTV).METHODS We retrospectively studied serumsamples from 192 transfusion recipients whounderwent cardiovascular surgery and bloodtransfusion betwe...AIM To investigate the role of bloodtransfusion in TT viral infection(TTV).METHODS We retrospectively studied serumsamples from 192 transfusion recipients whounderwent cardiovascular surgery and bloodtransfusion between July 1991 and June 1992.Allpatients had a follow-up every other week for atleast 6 months after transfusion.Eightyrecipients received blood before screeningdonors for hepatitis C antibody(anti-HCV),and112 recipients received screened blood.Recipients with alanine aminotransferase level】2.5 times the upper normal limit were testedfor serological markers for viral hepatitis A,B,C,G,Epstein-Barr virus and cytomegalovirus.TTV infection was defined by the positivity forserum TTV DNA using the polymerase chainreaction method.RESULTS Eleven and three patients,whoreceived anti-HCV unscreened and screened'blood,respectively,had serum ALT levels】90 IU/L.Five patients(HCV and TTV:1;HCV,HGV,and TTV:1;TTV:2;and CMV and TTV:1)were positive for TTV DNA,and four of them hadsero-conversion of TTV DNA.CONCLUSION TTV can be transmitted viablood transfusion.Two recipients infected byTTV alone may be associated with the hepatitis.However,whether TTV was the causal agentremains unsettled,and further studies arenecessary to define the role of TTV infection inchronic hepatitis.展开更多
The tracking, telemetry and command （TT＆C） mission is extremely reliable for its characters of small time horizon and high redundancy. The combined forcing and failure biasing （CFFB） method that is usually used f...The tracking, telemetry and command （TT＆C） mission is extremely reliable for its characters of small time horizon and high redundancy. The combined forcing and failure biasing （CFFB） method that is usually used for simulating the unreliability of the highly dependable mission system seems not so efficient for the TT＆C mission. The concept about the importance of failure transition is proposed based on the logical relationship between TT＆C mission and its involved resources. Then, the importance is used for readjusting the transition rate of the failure transition when using the forcing and failure biasing during the simulation. Examples show that the improved CFFB method can evidently increase the occurrence of the TT＆C mission failure event and decrease the sample variance. More redundancy of the TT＆C mission leads to the improved CFFB method more efficient.展开更多
Evolving From principal-subordinate structure of C /S to flexible multileveled distributed structure, i.e. B/S architecture so as to form a wide, distributed and orderly Internet/Intranet integrated management inf orm...Evolving From principal-subordinate structure of C /S to flexible multileveled distributed structure, i.e. B/S architecture so as to form a wide, distributed and orderly Internet/Intranet integrated management inf ormation system, is the trend of development of application software of the whol e world. Advantages and disadvantages of the two modes: C/S and B/S are compared . It is pointed out that at present onefold B/S mode cannot yet fully fullfil th e demands of some complicated data processing, information statistics and analys is, etc, therefore it still awaits further development of technology to achieve 100% Internet. In this paper, a mode of B/S-C/S-blended multileveled architect ure is discussed; the logical levels of B/S mode is studied; Furthermore, combin ing some up-to-date software developing technology, combinatorial design of di fferent database application technology based on B/S is discussed. The expatiati on is made with following points: (1) Organic combination of the network distrib uted object technology of CORBA and the computation technology among different n etwork operating system ─ Java; (2) Organic combination of two modes of ASP and Plug_in; (3) JDBC Server and JDBC Client; (4) An expanded B/S model, i.e. the c lient application of browser communicates directly with Web server, and the serv er application communicates directly with database server through middle ware.展开更多
The mechanical properties of ceramic cutting tool materials can be modified by introducing proper content of nanoparticles or whiskers.However,the process of adding whiskers or nanoparticles has the disadvantages of h...The mechanical properties of ceramic cutting tool materials can be modified by introducing proper content of nanoparticles or whiskers.However,the process of adding whiskers or nanoparticles has the disadvantages of high cost and health hazard as well as the agglomeration;although a new in-situ two-step sintering process can solve the above problems to some extent,yet the problems of low conversion ratio of the raw materials and the abnormal grain growth exist in this process.In this paper,an in-situ one-step synthesis technology is proposed,which means the growth of whiskers or nanoparticles and the sintering of the compact can be accomplished by one time in furnace.A kind of Ti（C,N）-based ceramic cutting tool material synergistically toughened by TiB_2 particles and whiskers is fabricated with this new process.The phase compositions,relationships between microstructure and mechanical properties as well as the toughening mechanisms are analyzed by means of X-ray diffraction（XRD）and scanning electron microscopy（SEM）.The composite which is sintered under a pressure of 32 MPa at a temperature of 1700℃in vacuum holding for 60 min can get the optimal mechanical properties.Its flexural strength,fracture toughness and Vickers hardness are 540 MPa,7.81 MPa·m（1/2）and 20.42 GPa,respectively.The composite has relatively high density,and the in-situ synthesized TiB_2 whiskers have good surface integrity,which is beneficial for the improvement of the fracture toughness.It is concluded that the main toughening mechanisms of the present composite are whiskers pulling-out and crack deflection induced by whiskers,crack bridging by whiskers/particles and multi-scale particles synergistically toughening.This study proposes an in-situ one-step synthesis technology which can be well used for fabricating particles and whiskers synergistically toughened ceramic tool materials.展开更多
基金This work was financially supported by the National High-Tech Research and Development Program of China(No.2001AA332020).
文摘The carbides/nitrides precipitates in ferrite grains, on grain boundaries and dislocations were investigated on a hot-rolled C-Mn strip （0.16wt%C-1.22wt%Mn-0.022wt%Ti） produced by the CSP （compact strip production） technology using TEM and X-ray energy dispersive spectroscopy. The Pickering＇s equation for the contribution of precipitates to the yield stress was also discussed. It is shown that there are numerous fine and dispersive precipitates TiC in the ferrite grains, on the grain boundaries and dislocations. Also there are a small amount of coarser Ti（C, N） particles and TiC particles associated with MnS. Precipitation strengthening on steels produced by the CSP technology is significant.
基金supported by Research and Practice on the reform of graduate education and teaching in Jiangsu Province in 2016(JGZZ16_065)
文摘The cultivation of innovative and entrepreneurial capability is a quality requirement of the times for the training of college and university talents. However, the regular teaching system universally has such problems as much more emphasis on theory than on practice, much more emphasis on inheritance than on innovation, and mismatching between talent training and market demand, so that a great number of graduates do not have enough innovative capacity, and it is very difficult for them to engage in related jobs of software engineering steadily and permanently. By investigating and analyzing similar majors of more than 20 schools at home and abroad, this article proposes a teaching system of talent training of the 3 C-cored major of "innovative and entrepreneurial" software engineering(digital media technology) based on regions, oriented to the industry and marked by school-enterprise linkage, and in connection with the characteristics of college and university education.
文摘A LM-3C carrier rocket at 0:53 Beijing time on December 25 was launched from the Xichang Satellite Launch Center,putting the Communications Technology Test Satellite 3 into its orbit.The satellite was developed by SAST for demonstrating related technologies.
文摘AIM To investigate the role of bloodtransfusion in TT viral infection(TTV).METHODS We retrospectively studied serumsamples from 192 transfusion recipients whounderwent cardiovascular surgery and bloodtransfusion between July 1991 and June 1992.Allpatients had a follow-up every other week for atleast 6 months after transfusion.Eightyrecipients received blood before screeningdonors for hepatitis C antibody(anti-HCV),and112 recipients received screened blood.Recipients with alanine aminotransferase level】2.5 times the upper normal limit were testedfor serological markers for viral hepatitis A,B,C,G,Epstein-Barr virus and cytomegalovirus.TTV infection was defined by the positivity forserum TTV DNA using the polymerase chainreaction method.RESULTS Eleven and three patients,whoreceived anti-HCV unscreened and screened'blood,respectively,had serum ALT levels】90 IU/L.Five patients(HCV and TTV:1;HCV,HGV,and TTV:1;TTV:2;and CMV and TTV:1)were positive for TTV DNA,and four of them hadsero-conversion of TTV DNA.CONCLUSION TTV can be transmitted viablood transfusion.Two recipients infected byTTV alone may be associated with the hepatitis.However,whether TTV was the causal agentremains unsettled,and further studies arenecessary to define the role of TTV infection inchronic hepatitis.
基金supported by the National Natural Science Foundation of China (71071159)
文摘The tracking, telemetry and command （TT＆C） mission is extremely reliable for its characters of small time horizon and high redundancy. The combined forcing and failure biasing （CFFB） method that is usually used for simulating the unreliability of the highly dependable mission system seems not so efficient for the TT＆C mission. The concept about the importance of failure transition is proposed based on the logical relationship between TT＆C mission and its involved resources. Then, the importance is used for readjusting the transition rate of the failure transition when using the forcing and failure biasing during the simulation. Examples show that the improved CFFB method can evidently increase the occurrence of the TT＆C mission failure event and decrease the sample variance. More redundancy of the TT＆C mission leads to the improved CFFB method more efficient.
文摘Evolving From principal-subordinate structure of C /S to flexible multileveled distributed structure, i.e. B/S architecture so as to form a wide, distributed and orderly Internet/Intranet integrated management inf ormation system, is the trend of development of application software of the whol e world. Advantages and disadvantages of the two modes: C/S and B/S are compared . It is pointed out that at present onefold B/S mode cannot yet fully fullfil th e demands of some complicated data processing, information statistics and analys is, etc, therefore it still awaits further development of technology to achieve 100% Internet. In this paper, a mode of B/S-C/S-blended multileveled architect ure is discussed; the logical levels of B/S mode is studied; Furthermore, combin ing some up-to-date software developing technology, combinatorial design of di fferent database application technology based on B/S is discussed. The expatiati on is made with following points: (1) Organic combination of the network distrib uted object technology of CORBA and the computation technology among different n etwork operating system ─ Java; (2) Organic combination of two modes of ASP and Plug_in; (3) JDBC Server and JDBC Client; (4) An expanded B/S model, i.e. the c lient application of browser communicates directly with Web server, and the serv er application communicates directly with database server through middle ware.
基金Supported by National Natural Science Foundation of China(Grant No.51175305)Key Special Project of Numerical Control Machine Tool of China(Grant No.2012ZX04003-051)China Postdoctoral Science Special Foundation(Grant No.2012T50610)
文摘The mechanical properties of ceramic cutting tool materials can be modified by introducing proper content of nanoparticles or whiskers.However,the process of adding whiskers or nanoparticles has the disadvantages of high cost and health hazard as well as the agglomeration;although a new in-situ two-step sintering process can solve the above problems to some extent,yet the problems of low conversion ratio of the raw materials and the abnormal grain growth exist in this process.In this paper,an in-situ one-step synthesis technology is proposed,which means the growth of whiskers or nanoparticles and the sintering of the compact can be accomplished by one time in furnace.A kind of Ti（C,N）-based ceramic cutting tool material synergistically toughened by TiB_2 particles and whiskers is fabricated with this new process.The phase compositions,relationships between microstructure and mechanical properties as well as the toughening mechanisms are analyzed by means of X-ray diffraction（XRD）and scanning electron microscopy（SEM）.The composite which is sintered under a pressure of 32 MPa at a temperature of 1700℃in vacuum holding for 60 min can get the optimal mechanical properties.Its flexural strength,fracture toughness and Vickers hardness are 540 MPa,7.81 MPa·m（1/2）and 20.42 GPa,respectively.The composite has relatively high density,and the in-situ synthesized TiB_2 whiskers have good surface integrity,which is beneficial for the improvement of the fracture toughness.It is concluded that the main toughening mechanisms of the present composite are whiskers pulling-out and crack deflection induced by whiskers,crack bridging by whiskers/particles and multi-scale particles synergistically toughening.This study proposes an in-situ one-step synthesis technology which can be well used for fabricating particles and whiskers synergistically toughened ceramic tool materials.
