A periodic pipe system composed of steel pipes and rubber hoses with the same inner radius is designed based on the theory of phononic crystals. Using the transfer matrix method, the band structure of the periodic pip...A periodic pipe system composed of steel pipes and rubber hoses with the same inner radius is designed based on the theory of phononic crystals. Using the transfer matrix method, the band structure of the periodic pipe is calculated considering the structural-acoustic coupling. The results show that longitudinal vibration band gaps and acoustic band gaps can coexist in the fluid-filled periodic pipe. The formation of the band gap mechanism is further analyzed. The band gaps are validated by the sound transmission loss and vibration-frequency response functions calculated using the finite element method. The effect of the damp on the band gap is analyzed by calculating the complex band structure. The periodic pipe system can be used not only in the field of vibration reduction but also for noise elimination.展开更多
Drug use （DU）, particularly injecting drug use （IDU） has been the main route of transmission and spread of Human Immunodeficiency Virus （HIV）/Acquired Immune Deficiency Syndrome （AIDSJ among injecting drug use...Drug use （DU）, particularly injecting drug use （IDU） has been the main route of transmission and spread of Human Immunodeficiency Virus （HIV）/Acquired Immune Deficiency Syndrome （AIDSJ among injecting drug users （IDUs）[1]. Previous studies have proven that needles or cottons sharing during drug injection were major risk factors for HIV/AIDS transmission at the personal level[z4]. Being a social behavioral issue, HIV/AIDS related risk factors should be far beyond the personal level. Therefore, studies on HIV/AIDS related risk factors should focus not only on the individual factors, but also on the association between HIV/AIDS cases and macroscopic-factors, such as economic status, transportation, health care services, etc[1]. The impact of the macroscopic-factors on HIV/AIDS status might be either positive or negative, which are potentially reflected in promoting, delaying or detecting HIV/AIDS epidemics.展开更多
The objective of the curtent study is to discuss the problems related to how data is used to calculate Yeare Lost with Disability (YLD) with the method recommended by the World Bank. The study includes collecting usef...The objective of the curtent study is to discuss the problems related to how data is used to calculate Yeare Lost with Disability (YLD) with the method recommended by the World Bank. The study includes collecting useful data, estimating disease duration and average age of disease onset,adjusting incidence and prevalence data by means of a software programme, DISMOD (Harvard University Incidence & Prevalence Model), and assessing the importance of YLD calculation for different diseases.Remission and fatality rates of 3 diseases were estimated by experts at 2 round consultations.Incidence rates, disease duration and average age of disease onset were calculated and adjusted by DISMOD. YLD due to schizothrenia is the highest among 4 diseases in two regions. YLD is 18. 88 % in disability adjusted life year for 4 diseases in Xiacheng District, and 19 .97 % in Fuyang County.Available data can be used for the calculation of YLD after being adjusted. DISMOD is a useful instrument to test the internal consistency of incidence, prevalence, rendssion and fatality rate. The adjusted data are acceptable to experts and DISMOD. To get rational remission and fatality rates, we can use a cohort method through expert consultations. To renect overall burden of disease, YLD calculation should be used.展开更多
-In this paper, the outset, evolution and intensity of El Nino were analyzed. Different features were found in each El Nino process. The El Nino of 1986 was also analyzed and outlined.
TOEFL(Test of English as a Foreign Language)is regarded as astandardized test of English proficiency. TOEFL consists of four sections.Listening Comprehension Section has threeparts,which give you an opportunity to dem...TOEFL(Test of English as a Foreign Language)is regarded as astandardized test of English proficiency. TOEFL consists of four sections.Listening Comprehension Section has threeparts,which give you an opportunity to demonstrate your ability to under-stand spoken English.展开更多
On the basis of the data obtained from the comprehensive Kuroshio surveys in 1987-1988,this paper analyses the oceanographic characteristics in the area (125°-130° E,27°-31° N) of the continental s...On the basis of the data obtained from the comprehensive Kuroshio surveys in 1987-1988,this paper analyses the oceanographic characteristics in the area (125°-130° E,27°-31° N) of the continental shelf edge of the East China Sea (E. C. S. ) and its adjacent waters and discusses the effects of the Kuroshio front,thermocline and upwelling of the Kuroshio subsurface water on the distribution of standing stock of phytoplankton (chlorophyll-a). The distribution of high content of chlorophylly-a has been detected at 20-50 in depth in the water body on the left side of the Kuroshio front in the continental shelf edge waters of the E. C. S. The high content of chlorophyll-a spreads from the shelf area to the Kuroshio area in the form of a tongue and connects with the maximum layer of subsurface chlorophyll-a of the Kuroshio and pelagic sea. The author considers that the formation of the distribution of high content chlorophyll-a in this area results from the bottom topography and oceanic environment and there are close correlations between the high content of chlorophyll-a and the light-nutrient environment.展开更多
An analysis of mutual interfering sources on RF systems using dual-band (Ka / X) radar is presented. The purpose of this paper is to improve operational performance of the system from the point of view of EMC design. ...An analysis of mutual interfering sources on RF systems using dual-band (Ka / X) radar is presented. The purpose of this paper is to improve operational performance of the system from the point of view of EMC design. The experimental dual-band antenna system have decreased the disturbing effects of most mutual interfering sources.展开更多
This paper is a study of the quantitative evaluation on the cost-effectiveness of air defense surveillance radars. The composition of life cycle cost of the radar is analysed at first. Then the radar performance and e...This paper is a study of the quantitative evaluation on the cost-effectiveness of air defense surveillance radars. The composition of life cycle cost of the radar is analysed at first. Then the radar performance and effectiveness formulas are derived. By calculating the values of many radars' cost, performance and effectiveness, tendency curves are plotted. The application of cost-effectiveness calculation and the tendency curves in radar system analysis is discussed at last.展开更多
An analysis was performed of the turbulent data obtained from Yucheng experimental station in the Shandong Province in 1984. [t is shown that at variant wind speed, the spectra of streamwise velocity remain similar an...An analysis was performed of the turbulent data obtained from Yucheng experimental station in the Shandong Province in 1984. [t is shown that at variant wind speed, the spectra of streamwise velocity remain similar and the intensity of wind fluctuations is proportional to wind speed in the downwind area of shelter belt. Therefore, we may decide the similarity of wind fluctuations by a speed scale and a length scale which is not correlated with stability, σu /V0 = F(X / H). The -5/3 power range of temperature spectra extends to lower frequency. The variation of ratio σ0 /T. with stability becomes σ0 / T . = C(X / H)( - Z / L)-1/3 . There is not such an extension of -5 / 3 power range in the humidity spectra.展开更多
This article utilizes a large amount of statistical data to analyze the global distribution of foreign trade in China since 1990,as well as the factors involved and the changes in trends.The research results indicate ...This article utilizes a large amount of statistical data to analyze the global distribution of foreign trade in China since 1990,as well as the factors involved and the changes in trends.The research results indicate that China has gained a favourable balance against developed countries and a disadvantageous balance against developing countries;China enjoys a trade surplus with North American and European countries while suffering deficits with those in the Asia.pacific region,as well as with resource-abundant Australia,Africa and South America. With regard to trends,the structure of China’s foreign trade will not undergo fundamental changes in the short term,but in the long run will be transformed in line with restructuring of the growth pattern.展开更多
Europeans are experiencing anxiety and confusion in trying to absorb a large number of foreign ethnic groups and heterogeneous cultures.This problem arises from the long-term effects of multiple factors.At present and...Europeans are experiencing anxiety and confusion in trying to absorb a large number of foreign ethnic groups and heterogeneous cultures.This problem arises from the long-term effects of multiple factors.At present and for the foreseeable future,a crucial problem for European countries will be this"Islamic Challenge,"how to integrate ever-increasing numbers of Muslims into European society.展开更多
In the aftermath of the September 11th events,the trend ofAmerican relations with Arab nations has become the importantfactor that influences the evolution of international pattern.Particular-ly,the changes of America...In the aftermath of the September 11th events,the trend ofAmerican relations with Arab nations has become the importantfactor that influences the evolution of international pattern.Particular-ly,the changes of American-Saudi relations attract worldwide atten-tion.This article tries to make a brief analysis and comment on the fea-展开更多
Seventy-eight cases of retinoblastoma (Rb) diagnosed at the Eye ENT Hospital, Shanghai Medical University from 1953 to 1985 were studied. The results of multiple logistic regression analysis and conditional probabilit...Seventy-eight cases of retinoblastoma (Rb) diagnosed at the Eye ENT Hospital, Shanghai Medical University from 1953 to 1985 were studied. The results of multiple logistic regression analysis and conditional probability model showed that high fetal order had a moderate risk (OR=1.28, P<0.05) of developing unilateral Rb. Both unilateral and bilateral cases were independent of parental ages, and no interaction could be found between fetal order and paternal of maternal age; also, the effect of fetal order was not confounded by parental ages.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11372346
文摘A periodic pipe system composed of steel pipes and rubber hoses with the same inner radius is designed based on the theory of phononic crystals. Using the transfer matrix method, the band structure of the periodic pipe is calculated considering the structural-acoustic coupling. The results show that longitudinal vibration band gaps and acoustic band gaps can coexist in the fluid-filled periodic pipe. The formation of the band gap mechanism is further analyzed. The band gaps are validated by the sound transmission loss and vibration-frequency response functions calculated using the finite element method. The effect of the damp on the band gap is analyzed by calculating the complex band structure. The periodic pipe system can be used not only in the field of vibration reduction but also for noise elimination.
基金supported by the National Scientific Research Mega-Project under the 12th Five-Year Plan of China(2012ZX10001001)
文摘Drug use （DU）, particularly injecting drug use （IDU） has been the main route of transmission and spread of Human Immunodeficiency Virus （HIV）/Acquired Immune Deficiency Syndrome （AIDSJ among injecting drug users （IDUs）[1]. Previous studies have proven that needles or cottons sharing during drug injection were major risk factors for HIV/AIDS transmission at the personal level[z4]. Being a social behavioral issue, HIV/AIDS related risk factors should be far beyond the personal level. Therefore, studies on HIV/AIDS related risk factors should focus not only on the individual factors, but also on the association between HIV/AIDS cases and macroscopic-factors, such as economic status, transportation, health care services, etc[1]. The impact of the macroscopic-factors on HIV/AIDS status might be either positive or negative, which are potentially reflected in promoting, delaying or detecting HIV/AIDS epidemics.
文摘The objective of the curtent study is to discuss the problems related to how data is used to calculate Yeare Lost with Disability (YLD) with the method recommended by the World Bank. The study includes collecting useful data, estimating disease duration and average age of disease onset,adjusting incidence and prevalence data by means of a software programme, DISMOD (Harvard University Incidence & Prevalence Model), and assessing the importance of YLD calculation for different diseases.Remission and fatality rates of 3 diseases were estimated by experts at 2 round consultations.Incidence rates, disease duration and average age of disease onset were calculated and adjusted by DISMOD. YLD due to schizothrenia is the highest among 4 diseases in two regions. YLD is 18. 88 % in disability adjusted life year for 4 diseases in Xiacheng District, and 19 .97 % in Fuyang County.Available data can be used for the calculation of YLD after being adjusted. DISMOD is a useful instrument to test the internal consistency of incidence, prevalence, rendssion and fatality rate. The adjusted data are acceptable to experts and DISMOD. To get rational remission and fatality rates, we can use a cohort method through expert consultations. To renect overall burden of disease, YLD calculation should be used.
文摘-In this paper, the outset, evolution and intensity of El Nino were analyzed. Different features were found in each El Nino process. The El Nino of 1986 was also analyzed and outlined.
文摘TOEFL(Test of English as a Foreign Language)is regarded as astandardized test of English proficiency. TOEFL consists of four sections.Listening Comprehension Section has threeparts,which give you an opportunity to demonstrate your ability to under-stand spoken English.
文摘On the basis of the data obtained from the comprehensive Kuroshio surveys in 1987-1988,this paper analyses the oceanographic characteristics in the area (125°-130° E,27°-31° N) of the continental shelf edge of the East China Sea (E. C. S. ) and its adjacent waters and discusses the effects of the Kuroshio front,thermocline and upwelling of the Kuroshio subsurface water on the distribution of standing stock of phytoplankton (chlorophyll-a). The distribution of high content of chlorophylly-a has been detected at 20-50 in depth in the water body on the left side of the Kuroshio front in the continental shelf edge waters of the E. C. S. The high content of chlorophyll-a spreads from the shelf area to the Kuroshio area in the form of a tongue and connects with the maximum layer of subsurface chlorophyll-a of the Kuroshio and pelagic sea. The author considers that the formation of the distribution of high content chlorophyll-a in this area results from the bottom topography and oceanic environment and there are close correlations between the high content of chlorophyll-a and the light-nutrient environment.
文摘An analysis of mutual interfering sources on RF systems using dual-band (Ka / X) radar is presented. The purpose of this paper is to improve operational performance of the system from the point of view of EMC design. The experimental dual-band antenna system have decreased the disturbing effects of most mutual interfering sources.
文摘This paper is a study of the quantitative evaluation on the cost-effectiveness of air defense surveillance radars. The composition of life cycle cost of the radar is analysed at first. Then the radar performance and effectiveness formulas are derived. By calculating the values of many radars' cost, performance and effectiveness, tendency curves are plotted. The application of cost-effectiveness calculation and the tendency curves in radar system analysis is discussed at last.
文摘An analysis was performed of the turbulent data obtained from Yucheng experimental station in the Shandong Province in 1984. [t is shown that at variant wind speed, the spectra of streamwise velocity remain similar and the intensity of wind fluctuations is proportional to wind speed in the downwind area of shelter belt. Therefore, we may decide the similarity of wind fluctuations by a speed scale and a length scale which is not correlated with stability, σu /V0 = F(X / H). The -5/3 power range of temperature spectra extends to lower frequency. The variation of ratio σ0 /T. with stability becomes σ0 / T . = C(X / H)( - Z / L)-1/3 . There is not such an extension of -5 / 3 power range in the humidity spectra.
文摘This article utilizes a large amount of statistical data to analyze the global distribution of foreign trade in China since 1990,as well as the factors involved and the changes in trends.The research results indicate that China has gained a favourable balance against developed countries and a disadvantageous balance against developing countries;China enjoys a trade surplus with North American and European countries while suffering deficits with those in the Asia.pacific region,as well as with resource-abundant Australia,Africa and South America. With regard to trends,the structure of China’s foreign trade will not undergo fundamental changes in the short term,but in the long run will be transformed in line with restructuring of the growth pattern.
文摘Europeans are experiencing anxiety and confusion in trying to absorb a large number of foreign ethnic groups and heterogeneous cultures.This problem arises from the long-term effects of multiple factors.At present and for the foreseeable future,a crucial problem for European countries will be this"Islamic Challenge,"how to integrate ever-increasing numbers of Muslims into European society.
文摘In the aftermath of the September 11th events,the trend ofAmerican relations with Arab nations has become the importantfactor that influences the evolution of international pattern.Particular-ly,the changes of American-Saudi relations attract worldwide atten-tion.This article tries to make a brief analysis and comment on the fea-
文摘Seventy-eight cases of retinoblastoma (Rb) diagnosed at the Eye ENT Hospital, Shanghai Medical University from 1953 to 1985 were studied. The results of multiple logistic regression analysis and conditional probability model showed that high fetal order had a moderate risk (OR=1.28, P<0.05) of developing unilateral Rb. Both unilateral and bilateral cases were independent of parental ages, and no interaction could be found between fetal order and paternal of maternal age; also, the effect of fetal order was not confounded by parental ages.
