AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human...AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.展开更多
Objective: To investigate the effect of Chinese medicine (CM) and Western medicine (WM) on quality of life (QOL) after conservative surgery for endometriosis. Methods: A total of 320 patients with endometdosis...Objective: To investigate the effect of Chinese medicine (CM) and Western medicine (WM) on quality of life (QOL) after conservative surgery for endometriosis. Methods: A total of 320 patients with endometdosis were randomized into two groups by using random block design, CM group (160 cases, activating blood circulation and removing blood stasis treatment based on syndrome differentiation) and WM group (160 cases, gonadotropin-releasing hormone agonist or gestrinone treatment) after conservative surgery. Treatment was given for 3-6 months (according to the revised American Fertility Society scoring system stage), and the Wodd Health Organization QOL-BREF (WHOQOL-BREF) was applied to patients before and after treatment to assess QOL. Results: There were 136 cases in the CM group and 141 cases in the WM group completing therapy. In the CM group, the use of the WHOQOL-BREF showed that the physical, psychological and environmental scores post- treatment were significantly higher than those at pre-treatment (P〈0.05), and for 12 items (pain and discomfort, energy and fatigue, sleep and rest, mobility, activities of daily living, work capacity, negative feelings, health and social care: accessibility and quality, participation in and opportunities for recreation/leisure activities, appetite, QOL score, overall health status and QOL), the difference in scores was significant (P〈0.05). In the WM group, 4 items (pain and discomfort, opportunities for acquiring new information and skills, QOI_ score, overall health status and QOL) had significantly different scores post-treatment compared with those at pre-treatment (P〈0.05). Before treatment, the QOL in the two groups of patients showed no significant difference (P〉0.05). After treatment, the scores for physical health in the CM group were significantly higher than those of the WM group (P〈0.05) and the scores of 4 items (mobility, activities of daily living, sexual activity, QOL score) in the CM展开更多
To develop uniform and seismic environment-dependent design spectrum,common acceleration response spectral characteristics need to be identified.In this paper,a bi-normalized response spectrum (BNRS) is proposed,which...To develop uniform and seismic environment-dependent design spectrum,common acceleration response spectral characteristics need to be identified.In this paper,a bi-normalized response spectrum (BNRS) is proposed,which is defined as a spectrum of peak response acceleration normalized with respect to peak acceleration of the excitation plotted vs.the natural period of the system normalized with respect to the spectrum predominant period,Tp.Based on a statistical analysis of records from the 1999 Chi-Chi earthquake,the conventionally normalized response spectrum(NRS) and the BNRS are examined to account for the effects of soil conditions,epicentral distance,hanging wall and damping.It is found that compared to the NRS the BNRS is much less dependent on these factors.Finally,some simple relationships between the BNRS for a specified damping ratio and that for a damping ratio of 5%,and between the spectra predominant period and epicentral distance for different soil types are provided.展开更多
This study aims to examine the impact of the China-ASEAN Free Trade Area (CAFTA) on China's international agricultural trade and its regional agricultural development, using the Global Trade Analysis Project model ...This study aims to examine the impact of the China-ASEAN Free Trade Area (CAFTA) on China's international agricultural trade and its regional agricultural development, using the Global Trade Analysis Project model and the China Agricultural Decision Support System. Our analysis showed that: (i) CAFTA will improve resource allocation efficiencies for both China and ASEAN and will promote bilateral agricultural trade and, hence, will have positive effects on the economic development of both sides; (ii) CAFTA will accelerate China's export of the agricultural commodities in which it has comparative advantages, such as vegetables, wheat and horticultural products, but at the same time bring about a large increase in imports of commodities such as vegetable oil and sugar; and (iii) CAFTA will have significantly varying impacts on China's regional agricultural development because of large differences in the agricultural production structure in each region. Our results indicate that agriculture in the northern, northeastern and eastern regions of China will benefit from CAFTA, whereas agriculture development in southern China will suffer. Those regional specific impacts are quite different from the effects brought by multilateral free trade treaties, such as those of the WTO, which usually have positive effects on south China but negative impacts on the northern and western parts of China.展开更多
A frequency and spatial domain decomposition method (FSDD) for operational modal analysis (OMA) is presented in this paper, which is an extension of the complex mode indicator function (CMIF) method for experime...A frequency and spatial domain decomposition method (FSDD) for operational modal analysis (OMA) is presented in this paper, which is an extension of the complex mode indicator function (CMIF) method for experimental modal analysis (EMA). The theoretical background of the FSDD method is clarified, Singular value decomposition is adopted to separate the signal space from the noise space. Finally, an enhanced power spectrum density (PSD) is proposed to obtain more accurate modal parameters by curve fitting in the frequency domain. Moreover, a simulation case and an application case are used to validate this method.展开更多
In this paper, antiplane response of an isosceles triangular hill to incident SH waves is studied based on the method of complex function and by using moving coordinate system. The standing wave function, which can sa...In this paper, antiplane response of an isosceles triangular hill to incident SH waves is studied based on the method of complex function and by using moving coordinate system. The standing wave function, which can satisfy the governing equation and boundary condition, is provided. Furthermore, numerical examples are presented; the influences of wave number and angle of the incident waves and the angle of the hill’s peak on ground motion are discussed.展开更多
The present study considers how education affects off-farm job participation and wages. We use a nationally representative dataset from a survey conducted in 5 provinces, 101 villages and 808 households by the authors...The present study considers how education affects off-farm job participation and wages. We use a nationally representative dataset from a survey conducted in 5 provinces, 101 villages and 808 households by the authors in early 2005. The empirical results show that educational attainment, skill training and years of experience of rural residents have positive, statistically significant effects on off-farm employment. The average return to a year of education is 7percent, which is higher than those observed in previous studies. We also find the return to an additional year of schooling to be higher for post-junior high schooling than for junior high and below schooling: 11.8 versus 3.2 percent. We conclude that not only does education still pays off in rural China, but also the rate of return to education is increasing over time.展开更多
Using nationally representative data, the present paper examines the impact of China's ongoing rural tax reform on farmers. The difficulties in further local governance restructuring are also discussed. It is argued ...Using nationally representative data, the present paper examines the impact of China's ongoing rural tax reform on farmers. The difficulties in further local governance restructuring are also discussed. It is argued that the issues associated with rural taxation and local governance in China result from inherent tension between an increasingly liberalized economic system and a still centralized political system. Although rural tax reform has helped to reduce farmers" tax burdens in the short term, the establishment of an effective local governance regime requires coordinated reforms to downsize local bureaucracy by providing social security for laid-off cadres, to strengthen local accountability by granting higher local formal tax autonomy, and to promote meaningful participation by expanding local democracy.展开更多
Objective: To investigate the effect of Shen-Fu (SF) injection on gastrointestinal tract injury and its potential mechanism.Methods: Thirty-eight patients undergoing elective open heart surgery were assigned to Group ...Objective: To investigate the effect of Shen-Fu (SF) injection on gastrointestinal tract injury and its potential mechanism.Methods: Thirty-eight patients undergoing elective open heart surgery were assigned to Group C (control group, n = 18) and Group SF (n = 20) randomly. In Group SF, the patients received intravenous injection of SF (0.5 ml/kg) at the beginning of the surgery followed by a continuous infusion of 100 ml SF (1.0 ml/kg) solution diluted by saline at a rate of 0.004 ml · Kg-1 · min-1 with a Grasby pump. The control group was injected with normal saline in the same volume. Gastric intramucosal pH (pHi), activity of blood diamine oxidase ( DAO ), and concentrations of blood LPS and IL-6 were measured before CPB ( S0) and 1 h ( S1 ) and 2 h ( S2) after aortic declamping, respectively.Results: In Group C, pHi value was significantly lower at S1 and S2 than at S0 ( mean P <0.01) and blood DAO and concentrations of LPS and IL-6 were significantly higher at S1 and S2 than at S0 ( meanP < 0.01). In Group SF, pHi was obviously lower at S1 and S2 than at S0(P< 0.05) but LPS and IL-6 levels and DAO were higher at S, (mean P<0.05). Blood DAO and LPS level demonstrated significant negative correlations with pHi ( mean P < 0.01) while LPS concentration showed a positive correlation with blood DAO (P < 0.01) and IL-6 concentration (P < 0.05). At S1 and S2 after aortic declamping, the levels of pHi were higher in Group SF than in Group C (mean P <0.01 ) but DAO and LPS and IL-6 levels were significantly lower in Group SF than in Group C ( P <0.01).Conclusions: SF has a protective effect on gastrointestinal tract and can reduce inflammatory actions.展开更多
A comparative analytical study of several control strategies for semi-active(SA) devices installed in baseisolated buildings aiming to reduce earthquake induced vibrations is presented.Three force tracking schemes com...A comparative analytical study of several control strategies for semi-active(SA) devices installed in baseisolated buildings aiming to reduce earthquake induced vibrations is presented.Three force tracking schemes comprising a linear controller plus a 'clipped' algorithm and a nonlinear output feedback controller(NOFC) are considered to tackle this problem.Linear controllers include the integral controller(I),the linear quadratic regulator(LQR) and the model predictive controller(MPC).A single degree-of-freedom system subjected to input accelerograms representative of the Portuguese seismic actions are first used to validate and evaluate the feasibility of these strategies.The obtained results show that structural systems using SA devices can in general outperform those equipped with passive devices for lower fundamental frequency structural systems,namely base-isolated buildings.The effectiveness of the proposed strategies is also evaluated on a 10 storey base-isolated dual frame-wall building.The force tracking scheme with an integral controller outperforms the other three as well as the original structure and the structure equipped with passive devices.展开更多
Loop heat pipes (LHPs) were designed for the alpha magnetic spectrometer (AMS-02) to dissipate heat from the cryocoolers. A bypass valve is applied to the LHP to keep the cryocooler temperature above its limit (...Loop heat pipes (LHPs) were designed for the alpha magnetic spectrometer (AMS-02) to dissipate heat from the cryocoolers. A bypass valve is applied to the LHP to keep the cryocooler temperature above its limit (-20℃) in cold environment. Extensive experiments were performed on operation characteristics of LHPs with the bypass valve for AMS-02 during thermal vacuum and thermal balance (TVTB) test. We found that the bypass valve can start up successfully in cold environment. With the bypass valve, the evaporator temperature is stable and can meet the requirement of the cryocooler. We analyzed three operating modes of the bypass valve. Set point temperature and regulation temperature shifts were observed and their relations with the bypass valve temperature were given.展开更多
The data of the meteorological elements in the surface layer have been analyzed which were obtained during the IOP of TIPEX from May to July 1998 inGěrzě, Damxung and Qamdo. The characteristics of th...The data of the meteorological elements in the surface layer have been analyzed which were obtained during the IOP of TIPEX from May to July 1998 inGěrzě, Damxung and Qamdo. The characteristics of the diurnal variations and the vertical profiles of the wind velocity, temperature and humidity in the surface layer have been investigated. Some interesting results have been obtained. The moisture inversion phenomena occured during the daytime in the surface layer have also been discussed.展开更多
The Hilbert-based time-frequency analysis has promising capacity to reveal the time-variant behaviors of a sys- tem.To admit well-behaved Hilbert transforms,component decomposition of signals must be performed beforeh...The Hilbert-based time-frequency analysis has promising capacity to reveal the time-variant behaviors of a sys- tem.To admit well-behaved Hilbert transforms,component decomposition of signals must be performed beforehand.This was first systematically implemented by the empirical mode decomposition(EMD)in the Hilbert-Huang transform,which can provide a time-frequency representation of the signals.The EMD,however,has limitations in distinguishing different components in narrowband signals commonly found in free-decay vibration signals.In this study,a technique for decompo- sing components in narrowband signals based on waves' beating phenomena is proposed to improve the EMD,in which the time scale structure of the signal is unveiled by the Hilbert transform as a result of wave beating,the order of component ex- traction is reversed from that in the EMD and the end effect is confined.The proposed technique is verified by performing the component decomposition of a simulated signal and a free decay signal actually measured in an instrumented bridge structure.In addition,the adaptability of the technique to time-variant dynamic systems is demonstrated with a simulated time-variant MDOF system.展开更多
Editor's Desk:The Internet of Things is an important part of the emerging high-tech industry and has been recognized as one of the important technologies for addressing global financial crisis and revitalizing the e...Editor's Desk:The Internet of Things is an important part of the emerging high-tech industry and has been recognized as one of the important technologies for addressing global financial crisis and revitalizing the economy. Therefore, at the beginning of the new year, we are honored to have invited Mr. Samuel Qi (Qi Qingzhong), a famous Chinese communication technology expert and GM of Shanghai Symphony Telecommunications Co., Ltd., to give his views on the development strategy of the Internet of Things and Machine to Machine (M2M) Communications.展开更多
文摘AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.
基金Supported by the "Eleventh-Five" National Technology Support Program Project(No.2006BAI04A17)
文摘Objective: To investigate the effect of Chinese medicine (CM) and Western medicine (WM) on quality of life (QOL) after conservative surgery for endometriosis. Methods: A total of 320 patients with endometdosis were randomized into two groups by using random block design, CM group (160 cases, activating blood circulation and removing blood stasis treatment based on syndrome differentiation) and WM group (160 cases, gonadotropin-releasing hormone agonist or gestrinone treatment) after conservative surgery. Treatment was given for 3-6 months (according to the revised American Fertility Society scoring system stage), and the Wodd Health Organization QOL-BREF (WHOQOL-BREF) was applied to patients before and after treatment to assess QOL. Results: There were 136 cases in the CM group and 141 cases in the WM group completing therapy. In the CM group, the use of the WHOQOL-BREF showed that the physical, psychological and environmental scores post- treatment were significantly higher than those at pre-treatment (P〈0.05), and for 12 items (pain and discomfort, energy and fatigue, sleep and rest, mobility, activities of daily living, work capacity, negative feelings, health and social care: accessibility and quality, participation in and opportunities for recreation/leisure activities, appetite, QOL score, overall health status and QOL), the difference in scores was significant (P〈0.05). In the WM group, 4 items (pain and discomfort, opportunities for acquiring new information and skills, QOI_ score, overall health status and QOL) had significantly different scores post-treatment compared with those at pre-treatment (P〈0.05). Before treatment, the QOL in the two groups of patients showed no significant difference (P〉0.05). After treatment, the scores for physical health in the CM group were significantly higher than those of the WM group (P〈0.05) and the scores of 4 items (mobility, activities of daily living, sexual activity, QOL score) in the CM
基金Heilongjiang Natural Science Foundation Under Project No.ZGJ03-03the Research Fund for the Doctoral Program of Higher Education of China Through Project No.20030213042
文摘To develop uniform and seismic environment-dependent design spectrum,common acceleration response spectral characteristics need to be identified.In this paper,a bi-normalized response spectrum (BNRS) is proposed,which is defined as a spectrum of peak response acceleration normalized with respect to peak acceleration of the excitation plotted vs.the natural period of the system normalized with respect to the spectrum predominant period,Tp.Based on a statistical analysis of records from the 1999 Chi-Chi earthquake,the conventionally normalized response spectrum(NRS) and the BNRS are examined to account for the effects of soil conditions,epicentral distance,hanging wall and damping.It is found that compared to the NRS the BNRS is much less dependent on these factors.Finally,some simple relationships between the BNRS for a specified damping ratio and that for a damping ratio of 5%,and between the spectra predominant period and epicentral distance for different soil types are provided.
基金the financial support of the National Natural Science Foundation of China(70603036)the Knowledge Innovation Program of the Chinese Academy of Sciences(KSCX2-YW-N-039)
文摘This study aims to examine the impact of the China-ASEAN Free Trade Area (CAFTA) on China's international agricultural trade and its regional agricultural development, using the Global Trade Analysis Project model and the China Agricultural Decision Support System. Our analysis showed that: (i) CAFTA will improve resource allocation efficiencies for both China and ASEAN and will promote bilateral agricultural trade and, hence, will have positive effects on the economic development of both sides; (ii) CAFTA will accelerate China's export of the agricultural commodities in which it has comparative advantages, such as vegetables, wheat and horticultural products, but at the same time bring about a large increase in imports of commodities such as vegetable oil and sugar; and (iii) CAFTA will have significantly varying impacts on China's regional agricultural development because of large differences in the agricultural production structure in each region. Our results indicate that agriculture in the northern, northeastern and eastern regions of China will benefit from CAFTA, whereas agriculture development in southern China will suffer. Those regional specific impacts are quite different from the effects brought by multilateral free trade treaties, such as those of the WTO, which usually have positive effects on south China but negative impacts on the northern and western parts of China.
基金China Postdoctoral Science Foundation Under Grant No. 2004035215 Jiangsu Planned Projects for Postdoctoral Research Funds 2004 Aeronautical Science Research Foundation Under Grant No. 04152065
文摘A frequency and spatial domain decomposition method (FSDD) for operational modal analysis (OMA) is presented in this paper, which is an extension of the complex mode indicator function (CMIF) method for experimental modal analysis (EMA). The theoretical background of the FSDD method is clarified, Singular value decomposition is adopted to separate the signal space from the noise space. Finally, an enhanced power spectrum density (PSD) is proposed to obtain more accurate modal parameters by curve fitting in the frequency domain. Moreover, a simulation case and an application case are used to validate this method.
文摘In this paper, antiplane response of an isosceles triangular hill to incident SH waves is studied based on the method of complex function and by using moving coordinate system. The standing wave function, which can satisfy the governing equation and boundary condition, is provided. Furthermore, numerical examples are presented; the influences of wave number and angle of the incident waves and the angle of the hill’s peak on ground motion are discussed.
基金the National Natural Science Foundation of China (No.7 0225003)the World Bank+1 种基金the Ford Foundationthe Canadian International Development Agency
文摘The present study considers how education affects off-farm job participation and wages. We use a nationally representative dataset from a survey conducted in 5 provinces, 101 villages and 808 households by the authors in early 2005. The empirical results show that educational attainment, skill training and years of experience of rural residents have positive, statistically significant effects on off-farm employment. The average return to a year of education is 7percent, which is higher than those observed in previous studies. We also find the return to an additional year of schooling to be higher for post-junior high schooling than for junior high and below schooling: 11.8 versus 3.2 percent. We conclude that not only does education still pays off in rural China, but also the rate of return to education is increasing over time.
基金financial support from the Chinese National Science Foundation(Project 703030l1,70633002)Ford Foundation+1 种基金the Chinese Academy of Science Innovation Project(KSCX2-YW-N.039)the Matching NSFC Fund of the Institute of Geographical Sciences and Natural Resource Research,the Chinese Academy of Sciences.
文摘Using nationally representative data, the present paper examines the impact of China's ongoing rural tax reform on farmers. The difficulties in further local governance restructuring are also discussed. It is argued that the issues associated with rural taxation and local governance in China result from inherent tension between an increasingly liberalized economic system and a still centralized political system. Although rural tax reform has helped to reduce farmers" tax burdens in the short term, the establishment of an effective local governance regime requires coordinated reforms to downsize local bureaucracy by providing social security for laid-off cadres, to strengthen local accountability by granting higher local formal tax autonomy, and to promote meaningful participation by expanding local democracy.
文摘Objective: To investigate the effect of Shen-Fu (SF) injection on gastrointestinal tract injury and its potential mechanism.Methods: Thirty-eight patients undergoing elective open heart surgery were assigned to Group C (control group, n = 18) and Group SF (n = 20) randomly. In Group SF, the patients received intravenous injection of SF (0.5 ml/kg) at the beginning of the surgery followed by a continuous infusion of 100 ml SF (1.0 ml/kg) solution diluted by saline at a rate of 0.004 ml · Kg-1 · min-1 with a Grasby pump. The control group was injected with normal saline in the same volume. Gastric intramucosal pH (pHi), activity of blood diamine oxidase ( DAO ), and concentrations of blood LPS and IL-6 were measured before CPB ( S0) and 1 h ( S1 ) and 2 h ( S2) after aortic declamping, respectively.Results: In Group C, pHi value was significantly lower at S1 and S2 than at S0 ( mean P <0.01) and blood DAO and concentrations of LPS and IL-6 were significantly higher at S1 and S2 than at S0 ( meanP < 0.01). In Group SF, pHi was obviously lower at S1 and S2 than at S0(P< 0.05) but LPS and IL-6 levels and DAO were higher at S, (mean P<0.05). Blood DAO and LPS level demonstrated significant negative correlations with pHi ( mean P < 0.01) while LPS concentration showed a positive correlation with blood DAO (P < 0.01) and IL-6 concentration (P < 0.05). At S1 and S2 after aortic declamping, the levels of pHi were higher in Group SF than in Group C (mean P <0.01 ) but DAO and LPS and IL-6 levels were significantly lower in Group SF than in Group C ( P <0.01).Conclusions: SF has a protective effect on gastrointestinal tract and can reduce inflammatory actions.
基金The Portuguese Foundation for Science and Technology(FCT)for the Ph D scholarship provided(reference SFRH/BD/84769/2012)
文摘A comparative analytical study of several control strategies for semi-active(SA) devices installed in baseisolated buildings aiming to reduce earthquake induced vibrations is presented.Three force tracking schemes comprising a linear controller plus a 'clipped' algorithm and a nonlinear output feedback controller(NOFC) are considered to tackle this problem.Linear controllers include the integral controller(I),the linear quadratic regulator(LQR) and the model predictive controller(MPC).A single degree-of-freedom system subjected to input accelerograms representative of the Portuguese seismic actions are first used to validate and evaluate the feasibility of these strategies.The obtained results show that structural systems using SA devices can in general outperform those equipped with passive devices for lower fundamental frequency structural systems,namely base-isolated buildings.The effectiveness of the proposed strategies is also evaluated on a 10 storey base-isolated dual frame-wall building.The force tracking scheme with an integral controller outperforms the other three as well as the original structure and the structure equipped with passive devices.
基金supported by the Major Project of Technology Transfer of Shandong Province (Grant No. 2009ZHZX1A1105)
文摘Loop heat pipes (LHPs) were designed for the alpha magnetic spectrometer (AMS-02) to dissipate heat from the cryocoolers. A bypass valve is applied to the LHP to keep the cryocooler temperature above its limit (-20℃) in cold environment. Extensive experiments were performed on operation characteristics of LHPs with the bypass valve for AMS-02 during thermal vacuum and thermal balance (TVTB) test. We found that the bypass valve can start up successfully in cold environment. With the bypass valve, the evaporator temperature is stable and can meet the requirement of the cryocooler. We analyzed three operating modes of the bypass valve. Set point temperature and regulation temperature shifts were observed and their relations with the bypass valve temperature were given.
基金This study was supported by the NKBRSF 61999043404 and the Program TIPEX. and partly supported by the Program KZCX2-204 of the C
文摘The data of the meteorological elements in the surface layer have been analyzed which were obtained during the IOP of TIPEX from May to July 1998 inGěrzě, Damxung and Qamdo. The characteristics of the diurnal variations and the vertical profiles of the wind velocity, temperature and humidity in the surface layer have been investigated. Some interesting results have been obtained. The moisture inversion phenomena occured during the daytime in the surface layer have also been discussed.
文摘The Hilbert-based time-frequency analysis has promising capacity to reveal the time-variant behaviors of a sys- tem.To admit well-behaved Hilbert transforms,component decomposition of signals must be performed beforehand.This was first systematically implemented by the empirical mode decomposition(EMD)in the Hilbert-Huang transform,which can provide a time-frequency representation of the signals.The EMD,however,has limitations in distinguishing different components in narrowband signals commonly found in free-decay vibration signals.In this study,a technique for decompo- sing components in narrowband signals based on waves' beating phenomena is proposed to improve the EMD,in which the time scale structure of the signal is unveiled by the Hilbert transform as a result of wave beating,the order of component ex- traction is reversed from that in the EMD and the end effect is confined.The proposed technique is verified by performing the component decomposition of a simulated signal and a free decay signal actually measured in an instrumented bridge structure.In addition,the adaptability of the technique to time-variant dynamic systems is demonstrated with a simulated time-variant MDOF system.
文摘Editor's Desk:The Internet of Things is an important part of the emerging high-tech industry and has been recognized as one of the important technologies for addressing global financial crisis and revitalizing the economy. Therefore, at the beginning of the new year, we are honored to have invited Mr. Samuel Qi (Qi Qingzhong), a famous Chinese communication technology expert and GM of Shanghai Symphony Telecommunications Co., Ltd., to give his views on the development strategy of the Internet of Things and Machine to Machine (M2M) Communications.