In this paper,using concentration data of PM2. 5in 2013 in China and referring to a lot of literature,we preliminary studied the pollution of fine particulate matter and summarized PM2. 5source apportionment in the ke...In this paper,using concentration data of PM2. 5in 2013 in China and referring to a lot of literature,we preliminary studied the pollution of fine particulate matter and summarized PM2. 5source apportionment in the key cities in China. Our results showed that PM2. 5showed significant spatial and temporal distribution; high surface concentrations of PM2. 5concentrated mainly in the North China Plain,the Sichuan Basin,Yangtze River Delta and other regions; the average annual concentration of PM2. 5was about 80μg / m3 in North China Plain; Seasonal changes in the concentration of PM2. 5was winter > spring > autumn > summer; fired sources,industrial sources,vehicle exhaust were the major sources of PM2. 5; motor vehicle exhaust mostly contributed 10%- 30% to PM2. 5. This review provides a fundamental understanding of PM2. 5source apportionment and serves as an important reference for future source apportionment studies to be widely conducted in China.展开更多
This paper studies correlations between the spatial structure character of thermal forcing and deformation and the amplitude of rays of meridional wave train. It is shown that if thermal forcing appears a meridional l...This paper studies correlations between the spatial structure character of thermal forcing and deformation and the amplitude of rays of meridional wave train. It is shown that if thermal forcing appears a meridional linear variation the rays of quasi-stationary planetary wave may propagate along oblique lines and if the meridional variability of heat source has second order term the rays show distinct deformation as a great circular route. Additionally, the inhomogeneous distribution may cause lower frequency oscillations in mid- and low-latitudes. The combination of zonal and meridional wave numbers and distributive character of heat source may form an inverse mechanism of variational trend of generized wave energy, reflecting in some degree the physical process of transition between meridional and zonal flow patterns.展开更多
As one of America’s first and foremost realists and humorist,Mark Twain,usually wrote aout his own personal experiences and things he knew about from firsthand experience.Among his books,The Adventures of Huckleberry...As one of America’s first and foremost realists and humorist,Mark Twain,usually wrote aout his own personal experiences and things he knew about from firsthand experience.Among his books,The Adventures of Huckleberry Finn has been considered the greatest one.In this paper I would argue that the Adventures of Huckleberry Finn is not merely a child’s story.It’s a book for the discerning adult.twain gives his young hero very adult problems.Actually,what are the adult problems of the young hero?What does it implied behind Huck’s adventures? This article aims to answer these questions and give more and deep analysis of Huck’s advetures.展开更多
Hydrological and hydro-chemical monitoring of nitrogen(N) and phosphorus(P) in a small urbanized catchment was conducted in the hilly area of the central Sichuan Basin,China,from 2010 through 2011.The diffuse N and P ...Hydrological and hydro-chemical monitoring of nitrogen(N) and phosphorus(P) in a small urbanized catchment was conducted in the hilly area of the central Sichuan Basin,China,from 2010 through 2011.The diffuse N and P loadings in different forms of total nitrogen(TN) and phosphorus(TP),dissolved nitrogen(DN) and phosphorus(DP),as well as particulate nitrogen(PN) and phosphorus(PP) were calculated based on runoff discharges and chemical analyses.The results revealed that the diffuse pollution concentrations of TN,DN,PN,TP,DP and PP exhibited large variations during rainfall events,with peak concentrations occurring during the initial period.For all of the measured parameters,the event mean concentrations(EMCs) were observed to clearly vary among rainfall events.The EMCs of TN,DN,PN,TP,DP and PP(for all of the observed rainfall events) were 10.04,6.62,3.42,1.30,0.47 and0.83 mg/L,respectively.The losses of diffuse N and P exhibited clear seasonal patterns and mainly occurred during the period from July through September,when the losses totaled 99.3 and 9.6 kg/ha for TN and TP,respectively,accounting for 75% and 74% of the total annual loadings.The mean annual loadings of TN and TP were 124.6 and 12.9 kg/ha,respectively.The results indicate that residential areas in the hilly areaof the central Sichuan Basin are subject to high diffuse N and P loadings,posing a serious risk to the receiving water quality.Ecological buffering belts are recommended to incorporate into the urbanized catchment to reduce diffuse pollution.展开更多
Based on the Joint Typhoon Warning Center(JTWC) best-track dataset between 1965 and 2009 and the characteristic parameters including tropical cyclone(TC) position,intensity,path length and direction,a method for objec...Based on the Joint Typhoon Warning Center(JTWC) best-track dataset between 1965 and 2009 and the characteristic parameters including tropical cyclone(TC) position,intensity,path length and direction,a method for objective classification of the Northwestern Pacific tropical cyclone tracks is established by using k-means Clustering.The TC lifespan,energy,active season and landfall probability of seven clusters of tropical cyclone tracks are comparatively analyzed.The characteristics of these parameters are quite different among different tropical cyclone track clusters.From the trend of the past two decades,the frequency of the western recurving cluster(accounting for 21.3% of the total) increased,and the lifespan elongated slightly,which differs from the other clusters.The annual variation of the Power Dissipation Index(PDI) of most clusters mainly depended on the TC intensity and frequency.However,the annual variation of the PDI in the northwestern moving then recurving cluster and the pelagic west-northwest moving cluster mainly depended on the frequency.展开更多
In the present communication, we have obtained the optimum probability distribution with which the messages should be delivered so that the average redundancy of the source is minimized. Here, we have taken the case o...In the present communication, we have obtained the optimum probability distribution with which the messages should be delivered so that the average redundancy of the source is minimized. Here, we have taken the case of various generalized mean codeword lengths. Moreover, the upper bound to these codeword lengths has been found for the case of Huffman encoding.展开更多
In this paper,we use the elementary methods,the properties of Dirichlet character sums and the classical Gauss sums to study the estimation of the mean value of high-powers for a special character sum modulo a prime,a...In this paper,we use the elementary methods,the properties of Dirichlet character sums and the classical Gauss sums to study the estimation of the mean value of high-powers for a special character sum modulo a prime,and derive an exact computational formula.It can be conveniently programmed by the“Mathematica”software,by which we can get the exact results easily.展开更多
Hanzi (Chinese characters) has a long history and affluent contents. To promote the popularity of historical and cultural knowledge of Chinese characters, an online program has been launched by Beihang University an...Hanzi (Chinese characters) has a long history and affluent contents. To promote the popularity of historical and cultural knowledge of Chinese characters, an online program has been launched by Beihang University and Beijing Normal University to explain Chinese characters' original meanings and evolution processes with vivid and expressive animation videos. Currently, More than 1,000 videos can be accessed through the website “http://www.chinesecharacter.org/”. Besides these online resources, a human-computer interaction system is also proposed to simulate clerical changes of Chinese characters through computer morphing technology. What we want is to make the teaching and learning of Chinese characters more reasonable, more easily understandable and more interesting.展开更多
This paper aims at explaining the importance and function of the character Lena Grove in William Faulkner’s famous novel Light in August. The meaning of the title is explored by making comparisons between Lena and ot...This paper aims at explaining the importance and function of the character Lena Grove in William Faulkner’s famous novel Light in August. The meaning of the title is explored by making comparisons between Lena and other main characters.展开更多
Symbolism is one of the most important and effective means in English writing."Lord of the Flies"written by William Golding is a successful use of it and has received hot discussions from its publication. Th...Symbolism is one of the most important and effective means in English writing."Lord of the Flies"written by William Golding is a successful use of it and has received hot discussions from its publication. The symbolic meaning of the characters and the Conch and the Fire in the novel make the novel an allegory that is entirely symbolic.展开更多
To elucidate the genetic relationship of the soybean varieties registered in Henan province, we analyzed the pedigrees, the major agronomic traits, and the eco- nomic traits of 74 soybean varieties registered in Henan...To elucidate the genetic relationship of the soybean varieties registered in Henan province, we analyzed the pedigrees, the major agronomic traits, and the eco- nomic traits of 74 soybean varieties registered in Henan province from 1985 to 2012, with reference to experience and technologies beneficial to breeding. The resuits indicated that these varieties originated from 113 parents, and positive correla- tion between the yield and the number of original parents was significant. In the major agronomic traits, the growth stage was about 106 days with relatively small variation, while the final height varied largely among these varieties. Among the fac- tore affecting the final yield, the pod number per plant exhibited an increasing trend, while the variation of 100-grain weight was relatively small. More than 50% of the 113 original parents came from Henan Province and its neighbor provinces, and the genetic relationship among the registered varieties was too close. The rational criteria of yield components of soybean varieties in Henan Province should be as fol- lows: the pod number per plant was about 48. 6, with 100-grain weight ranging from 17.55 g to 21.80 g.展开更多
Rope is a short story written by the American writer Katherine Anne Porter.It mainly tells a quarrel between husband and wife triggered by an incident that the husband brought a package of rope that they don't nee...Rope is a short story written by the American writer Katherine Anne Porter.It mainly tells a quarrel between husband and wife triggered by an incident that the husband brought a package of rope that they don't need but forgot to buy the wife coffee.Focusing on artistic expression of Rope,in this essay,we try to analyze the female character,the author's writing style and the theme and symbolic meaning in this story.And this analysis aims to excavate female consciousness and self-identification,to illustrate Porter's writing style of special discourse modes,third-party narrative point of view,rich rhetorical tactics and open ending,and to dissect the theme of love and disillusionment in marital life and the double symbolic meaning of the rope.展开更多
On the basis of tests and studies for many years, wheat cold source has been discovered in natural world. It is a donor material supplying a low temperature and causing stronger cooling effect, that is, the canopy tem...On the basis of tests and studies for many years, wheat cold source has been discovered in natural world. It is a donor material supplying a low temperature and causing stronger cooling effect, that is, the canopy temperature of its progeny can be descended universally and some non-cold type acceptor wheat can turn into cold type wheat having good metabolic functions under the condition of that acceptor wheat accepts the gamete of donor wheat supplying a low temperature. Contrast between wheat cold source and general wheat having no the ability of supplying a low temperature shows that second heat source temperature and plant temperature of wheat cold source not only are lower than those of general wheat but its root vigor, rate of awn etiolation, functional duration of leaf, chlorophyll content, soluble protein content, SOD activity, net photosynthetic rate, etc, are also more excellent than those of general wheat, and these all provide certain ecological and physiological bases for the distinction and selection of wheat cold source.展开更多
A lot of experimental methods have been brought forth to assess the dynamic character of the arc welding power source, but up to now, this issue has not been solved very well. In this paper, based on the fuzzy logic r...A lot of experimental methods have been brought forth to assess the dynamic character of the arc welding power source, but up to now, this issue has not been solved very well. In this paper, based on the fuzzy logic reasoning method, a dynamic character assessing model for the arc welding power source was established and used to analyze the dynamic character of the welding power source. Three different types of welding machine have been tested, and the characteristic information of the electrical signals such as re-striking arc voltage, low welding current and so on of the welding process were extracted accurately by using a self-developed welding dynamic arc wavelet analyzer. The experimental results indicate that this model can be used as a new assessing method for the dynamic character of the arc welding power source.展开更多
At present,there are unharmonious factors existing in Chinese family education,which particular manifest in the means of family education.The Three Character Primer,as an epitome of the essence of Chinese traditional ...At present,there are unharmonious factors existing in Chinese family education,which particular manifest in the means of family education.The Three Character Primer,as an epitome of the essence of Chinese traditional culture,can provide enlightenment on building a democratic and harmonious family education means.展开更多
The main purpose of this paper is using the properties of the classical Gauss sum and the analytic methods to study the computational problem of one kind of hybrid power mean involving the character sum of polynomials...The main purpose of this paper is using the properties of the classical Gauss sum and the analytic methods to study the computational problem of one kind of hybrid power mean involving the character sum of polynomials and a sum analogous to Kloosterman sum mod p,an odd prime,and give two sharp asymptotic formulae for them.展开更多
The inversion of modern tectonic stress field in China is made by regions on the basis of focal mechanism data inthe period of 1920-1996. Results of the inversion show that the maximum principal compressive stress σ1...The inversion of modern tectonic stress field in China is made by regions on the basis of focal mechanism data inthe period of 1920-1996. Results of the inversion show that the maximum principal compressive stress σ1 axisstrikes nearly north-south direction in the Tibet Plateau and western Chin4 east-west direction in North China Incentral China, its strikes show a radiate pattern, i.e., north-north east in north part, east-west in central part andnorth-north west in south part. The σ1 axes are often perpendicular to the minimum principal stress σ3 axes, exceptwestern China where the σ1 axes are oblique to the σ3 axes with an acute angle. R is defined by (σ2-σ1)/(σ3-σ1),has the higher values (0.60-0.90) in north part of central China and quickly changes into the lower values(0. 10-0.30) in the Tibet Plateau. Both of the observed and inverted fault planes have strikes varying with locations.Combining stress directions and R value, the stress configuration is divided into 7 groups. Most of the groups showstrike-slip faulting with intermediate R values, which occupies North China and the eastern part of China as well asinner Tibet Plateau. A few of them show reverse faulting with higher R values within western pod of China and thenorth edge of the Tibet Plateau. Normal faulting occurred on the south edge of the Tibet Plateau with smaller Rval nes.展开更多
The compact super-fluorescent fiber source (SFS) output spectra variations at different pump currents and under different dose of gamma-ray radiation were measured and compared respectively. The radiation-induced at...The compact super-fluorescent fiber source (SFS) output spectra variations at different pump currents and under different dose of gamma-ray radiation were measured and compared respectively. The radiation-induced attenuation (RIA) self-compensating effect in SFS based on photo-bleaching was found and the general mathematic model of SFS output spectra variations was made. The radiation-induced background attenuation (RIBA) at the pump wavelength was identified to be the main cause of the total output power and spectra variations and the variations can then be compensated by active control of the pump power to enhance the self-compensating effect. With closed-loop feedback control of pump current, double-pass backward (DPB) configuration and spectrum re-shaping technology, an SFS prototype was made and tested. The mean-wavelength stability of about 87.4 ppm and output power instability of less than 5% were achieved under up to 200 krad (Si) gamma-ray irradiation.展开更多
The main purpose of this paper is, using the analytic method, to study the mean value properties of the complete trigonometric sums with Dirichlet characters, and give an exact calculating formula for its fourth power...The main purpose of this paper is, using the analytic method, to study the mean value properties of the complete trigonometric sums with Dirichlet characters, and give an exact calculating formula for its fourth power mean.展开更多
The effects of the variations in fiber length,fiber mirror reflectance on efficiency and output power are experimentally investigated for erbium-doped double pass backward superfluorescent fiber sources (SFSs).The inf...The effects of the variations in fiber length,fiber mirror reflectance on efficiency and output power are experimentally investigated for erbium-doped double pass backward superfluorescent fiber sources (SFSs).The influence of fiber length on mean wavelength stability (MWS) has also been demonstrated.By incorporating a short section of un-pumped erbium-doped fiber (EDF) at the output port,the pump power dependent on MWS becomes independent of pumped EDF length.This is a novel phenomenon that hasn’t been reported up to now,and should be helpful to SFS fabrication and theory analysis.By using a fiber Michelson interferometer as spectrum slicing component,a multi-wavelength fiber source (MWFS) with ~20 channels (from 1 542 nm to 1 559 nm) is got.The MWFS has a channel spacing of ~0.8 nm which satisfies ITU-standard.The intensity fluctuation among channels is less than 0.5 dB,and the extinction ratio of all channels is above 14 dB.This kind of MWFS should be useful to wavelength division multiplexing systems.展开更多
文摘In this paper,using concentration data of PM2. 5in 2013 in China and referring to a lot of literature,we preliminary studied the pollution of fine particulate matter and summarized PM2. 5source apportionment in the key cities in China. Our results showed that PM2. 5showed significant spatial and temporal distribution; high surface concentrations of PM2. 5concentrated mainly in the North China Plain,the Sichuan Basin,Yangtze River Delta and other regions; the average annual concentration of PM2. 5was about 80μg / m3 in North China Plain; Seasonal changes in the concentration of PM2. 5was winter > spring > autumn > summer; fired sources,industrial sources,vehicle exhaust were the major sources of PM2. 5; motor vehicle exhaust mostly contributed 10%- 30% to PM2. 5. This review provides a fundamental understanding of PM2. 5source apportionment and serves as an important reference for future source apportionment studies to be widely conducted in China.
文摘This paper studies correlations between the spatial structure character of thermal forcing and deformation and the amplitude of rays of meridional wave train. It is shown that if thermal forcing appears a meridional linear variation the rays of quasi-stationary planetary wave may propagate along oblique lines and if the meridional variability of heat source has second order term the rays show distinct deformation as a great circular route. Additionally, the inhomogeneous distribution may cause lower frequency oscillations in mid- and low-latitudes. The combination of zonal and meridional wave numbers and distributive character of heat source may form an inverse mechanism of variational trend of generized wave energy, reflecting in some degree the physical process of transition between meridional and zonal flow patterns.
文摘As one of America’s first and foremost realists and humorist,Mark Twain,usually wrote aout his own personal experiences and things he knew about from firsthand experience.Among his books,The Adventures of Huckleberry Finn has been considered the greatest one.In this paper I would argue that the Adventures of Huckleberry Finn is not merely a child’s story.It’s a book for the discerning adult.twain gives his young hero very adult problems.Actually,what are the adult problems of the young hero?What does it implied behind Huck’s adventures? This article aims to answer these questions and give more and deep analysis of Huck’s advetures.
基金provided by the Innovative Team Program of Chinese Academy of Sciences (Grant No.KZZD-EW-TZ-06)the National Natural Science Foundation of China (Grant No.41430750)the National Science & Technology Pillar Program (Grant No.2011BAD31B03)
文摘Hydrological and hydro-chemical monitoring of nitrogen(N) and phosphorus(P) in a small urbanized catchment was conducted in the hilly area of the central Sichuan Basin,China,from 2010 through 2011.The diffuse N and P loadings in different forms of total nitrogen(TN) and phosphorus(TP),dissolved nitrogen(DN) and phosphorus(DP),as well as particulate nitrogen(PN) and phosphorus(PP) were calculated based on runoff discharges and chemical analyses.The results revealed that the diffuse pollution concentrations of TN,DN,PN,TP,DP and PP exhibited large variations during rainfall events,with peak concentrations occurring during the initial period.For all of the measured parameters,the event mean concentrations(EMCs) were observed to clearly vary among rainfall events.The EMCs of TN,DN,PN,TP,DP and PP(for all of the observed rainfall events) were 10.04,6.62,3.42,1.30,0.47 and0.83 mg/L,respectively.The losses of diffuse N and P exhibited clear seasonal patterns and mainly occurred during the period from July through September,when the losses totaled 99.3 and 9.6 kg/ha for TN and TP,respectively,accounting for 75% and 74% of the total annual loadings.The mean annual loadings of TN and TP were 124.6 and 12.9 kg/ha,respectively.The results indicate that residential areas in the hilly areaof the central Sichuan Basin are subject to high diffuse N and P loadings,posing a serious risk to the receiving water quality.Ecological buffering belts are recommended to incorporate into the urbanized catchment to reduce diffuse pollution.
基金National Basic Research Program of China(973 Program)(2015CB453200),2012CB955903)National Natural Science Foundation of China(41575083,41575108)Jiangsu Education Science Foundation(13KJA170002)
文摘Based on the Joint Typhoon Warning Center(JTWC) best-track dataset between 1965 and 2009 and the characteristic parameters including tropical cyclone(TC) position,intensity,path length and direction,a method for objective classification of the Northwestern Pacific tropical cyclone tracks is established by using k-means Clustering.The TC lifespan,energy,active season and landfall probability of seven clusters of tropical cyclone tracks are comparatively analyzed.The characteristics of these parameters are quite different among different tropical cyclone track clusters.From the trend of the past two decades,the frequency of the western recurving cluster(accounting for 21.3% of the total) increased,and the lifespan elongated slightly,which differs from the other clusters.The annual variation of the Power Dissipation Index(PDI) of most clusters mainly depended on the TC intensity and frequency.However,the annual variation of the PDI in the northwestern moving then recurving cluster and the pelagic west-northwest moving cluster mainly depended on the frequency.
文摘In the present communication, we have obtained the optimum probability distribution with which the messages should be delivered so that the average redundancy of the source is minimized. Here, we have taken the case of various generalized mean codeword lengths. Moreover, the upper bound to these codeword lengths has been found for the case of Huffman encoding.
文摘In this paper,we use the elementary methods,the properties of Dirichlet character sums and the classical Gauss sums to study the estimation of the mean value of high-powers for a special character sum modulo a prime,and derive an exact computational formula.It can be conveniently programmed by the“Mathematica”software,by which we can get the exact results easily.
文摘Hanzi (Chinese characters) has a long history and affluent contents. To promote the popularity of historical and cultural knowledge of Chinese characters, an online program has been launched by Beihang University and Beijing Normal University to explain Chinese characters' original meanings and evolution processes with vivid and expressive animation videos. Currently, More than 1,000 videos can be accessed through the website “http://www.chinesecharacter.org/”. Besides these online resources, a human-computer interaction system is also proposed to simulate clerical changes of Chinese characters through computer morphing technology. What we want is to make the teaching and learning of Chinese characters more reasonable, more easily understandable and more interesting.
文摘This paper aims at explaining the importance and function of the character Lena Grove in William Faulkner’s famous novel Light in August. The meaning of the title is explored by making comparisons between Lena and other main characters.
文摘Symbolism is one of the most important and effective means in English writing."Lord of the Flies"written by William Golding is a successful use of it and has received hot discussions from its publication. The symbolic meaning of the characters and the Conch and the Fire in the novel make the novel an allegory that is entirely symbolic.
基金Supported by National Soybean Industrial Technology Support Program(nycytx-004)National Scientific and Technological Innovation ProgramIndigenuous Innovative Program of Henan Academy of Agricultural Science~~
文摘To elucidate the genetic relationship of the soybean varieties registered in Henan province, we analyzed the pedigrees, the major agronomic traits, and the eco- nomic traits of 74 soybean varieties registered in Henan province from 1985 to 2012, with reference to experience and technologies beneficial to breeding. The resuits indicated that these varieties originated from 113 parents, and positive correla- tion between the yield and the number of original parents was significant. In the major agronomic traits, the growth stage was about 106 days with relatively small variation, while the final height varied largely among these varieties. Among the fac- tore affecting the final yield, the pod number per plant exhibited an increasing trend, while the variation of 100-grain weight was relatively small. More than 50% of the 113 original parents came from Henan Province and its neighbor provinces, and the genetic relationship among the registered varieties was too close. The rational criteria of yield components of soybean varieties in Henan Province should be as fol- lows: the pod number per plant was about 48. 6, with 100-grain weight ranging from 17.55 g to 21.80 g.
文摘Rope is a short story written by the American writer Katherine Anne Porter.It mainly tells a quarrel between husband and wife triggered by an incident that the husband brought a package of rope that they don't need but forgot to buy the wife coffee.Focusing on artistic expression of Rope,in this essay,we try to analyze the female character,the author's writing style and the theme and symbolic meaning in this story.And this analysis aims to excavate female consciousness and self-identification,to illustrate Porter's writing style of special discourse modes,third-party narrative point of view,rich rhetorical tactics and open ending,and to dissect the theme of love and disillusionment in marital life and the double symbolic meaning of the rope.
基金the National Nature Science Foundation of China (No. 39870477,30070150).
文摘On the basis of tests and studies for many years, wheat cold source has been discovered in natural world. It is a donor material supplying a low temperature and causing stronger cooling effect, that is, the canopy temperature of its progeny can be descended universally and some non-cold type acceptor wheat can turn into cold type wheat having good metabolic functions under the condition of that acceptor wheat accepts the gamete of donor wheat supplying a low temperature. Contrast between wheat cold source and general wheat having no the ability of supplying a low temperature shows that second heat source temperature and plant temperature of wheat cold source not only are lower than those of general wheat but its root vigor, rate of awn etiolation, functional duration of leaf, chlorophyll content, soluble protein content, SOD activity, net photosynthetic rate, etc, are also more excellent than those of general wheat, and these all provide certain ecological and physiological bases for the distinction and selection of wheat cold source.
基金This work is supported by Guangdong Natural Science Fund (04020100)
文摘A lot of experimental methods have been brought forth to assess the dynamic character of the arc welding power source, but up to now, this issue has not been solved very well. In this paper, based on the fuzzy logic reasoning method, a dynamic character assessing model for the arc welding power source was established and used to analyze the dynamic character of the welding power source. Three different types of welding machine have been tested, and the characteristic information of the electrical signals such as re-striking arc voltage, low welding current and so on of the welding process were extracted accurately by using a self-developed welding dynamic arc wavelet analyzer. The experimental results indicate that this model can be used as a new assessing method for the dynamic character of the arc welding power source.
文摘At present,there are unharmonious factors existing in Chinese family education,which particular manifest in the means of family education.The Three Character Primer,as an epitome of the essence of Chinese traditional culture,can provide enlightenment on building a democratic and harmonious family education means.
基金Supported by NSFC(No.12126357)Natural Science Basic Research Plan in Shaanxi Province of China(No.2023-JC-QN-0058)。
文摘The main purpose of this paper is using the properties of the classical Gauss sum and the analytic methods to study the computational problem of one kind of hybrid power mean involving the character sum of polynomials and a sum analogous to Kloosterman sum mod p,an odd prime,and give two sharp asymptotic formulae for them.
文摘The inversion of modern tectonic stress field in China is made by regions on the basis of focal mechanism data inthe period of 1920-1996. Results of the inversion show that the maximum principal compressive stress σ1 axisstrikes nearly north-south direction in the Tibet Plateau and western Chin4 east-west direction in North China Incentral China, its strikes show a radiate pattern, i.e., north-north east in north part, east-west in central part andnorth-north west in south part. The σ1 axes are often perpendicular to the minimum principal stress σ3 axes, exceptwestern China where the σ1 axes are oblique to the σ3 axes with an acute angle. R is defined by (σ2-σ1)/(σ3-σ1),has the higher values (0.60-0.90) in north part of central China and quickly changes into the lower values(0. 10-0.30) in the Tibet Plateau. Both of the observed and inverted fault planes have strikes varying with locations.Combining stress directions and R value, the stress configuration is divided into 7 groups. Most of the groups showstrike-slip faulting with intermediate R values, which occupies North China and the eastern part of China as well asinner Tibet Plateau. A few of them show reverse faulting with higher R values within western pod of China and thenorth edge of the Tibet Plateau. Normal faulting occurred on the south edge of the Tibet Plateau with smaller Rval nes.
基金supported by the Special Fund for Development of National Major Scientific Instruments of China(Grant No.2013YQ04081504)the Program for Innovative Research Team in University,China(Grant No.IRT 1203)
文摘The compact super-fluorescent fiber source (SFS) output spectra variations at different pump currents and under different dose of gamma-ray radiation were measured and compared respectively. The radiation-induced attenuation (RIA) self-compensating effect in SFS based on photo-bleaching was found and the general mathematic model of SFS output spectra variations was made. The radiation-induced background attenuation (RIBA) at the pump wavelength was identified to be the main cause of the total output power and spectra variations and the variations can then be compensated by active control of the pump power to enhance the self-compensating effect. With closed-loop feedback control of pump current, double-pass backward (DPB) configuration and spectrum re-shaping technology, an SFS prototype was made and tested. The mean-wavelength stability of about 87.4 ppm and output power instability of less than 5% were achieved under up to 200 krad (Si) gamma-ray irradiation.
文摘The main purpose of this paper is, using the analytic method, to study the mean value properties of the complete trigonometric sums with Dirichlet characters, and give an exact calculating formula for its fourth power mean.
文摘The effects of the variations in fiber length,fiber mirror reflectance on efficiency and output power are experimentally investigated for erbium-doped double pass backward superfluorescent fiber sources (SFSs).The influence of fiber length on mean wavelength stability (MWS) has also been demonstrated.By incorporating a short section of un-pumped erbium-doped fiber (EDF) at the output port,the pump power dependent on MWS becomes independent of pumped EDF length.This is a novel phenomenon that hasn’t been reported up to now,and should be helpful to SFS fabrication and theory analysis.By using a fiber Michelson interferometer as spectrum slicing component,a multi-wavelength fiber source (MWFS) with ~20 channels (from 1 542 nm to 1 559 nm) is got.The MWFS has a channel spacing of ~0.8 nm which satisfies ITU-standard.The intensity fluctuation among channels is less than 0.5 dB,and the extinction ratio of all channels is above 14 dB.This kind of MWFS should be useful to wavelength division multiplexing systems.