Soil organic carbon(SOC)can act as a sink or source of atmospheric carbon dioxide;therefore,it is important to understand the amount and composition of SOC in terrestrial ecosystems,the spatial variation in SOC,and th...Soil organic carbon(SOC)can act as a sink or source of atmospheric carbon dioxide;therefore,it is important to understand the amount and composition of SOC in terrestrial ecosystems,the spatial variation in SOC,and the underlying mechanisms that stabilize SOC.In this study,density fractionation and acid hydrolysis were used to assess the spatial variation in SOC,the heavy fraction of organic carbon(HFOC),and the resistant organic carbon(ROC)in soils of the southern Hulun Buir region,northeastern China,and to identify the major factors that contribute to this variation.The results showed that as the contents of clay and silt particles(0–50μm)increased,both methylene blue(MB)adsorption by soil minerals and microaggregate contents increased in the 0–20 and 20–40 cm soil layers(P<0.05).Although varying with vegetation types,SOC,HFOC,and ROC contents increased significantly with the content of clay and silt particles, MB adsorption by soil minerals,and microaggregate content(P<0.05),suggesting that soil texture,the MB adsorption by soil minerals,and microaggregate abundance might be important factors influencing the spatial heterogeneity of carbon contents in soils of the southern Hulun Buir region.展开更多
A generalized Lyapunov function was employed to investigate the ultimate bound and positively invariant set of a generalized Lorenz system.We derived an ellipsoidal estimate of the ultimate bound and positively invari...A generalized Lyapunov function was employed to investigate the ultimate bound and positively invariant set of a generalized Lorenz system.We derived an ellipsoidal estimate of the ultimate bound and positively invariant set for the generalized Lorenz system,for all the positive values of system parameters a,b,and c.Our results extend the related result of Li,et al.[Li DM,Lu JA,Wu XQ,et al.,Estimating the ultimate bound and positively invariant set for the Lorenz system and a unified chaotic system,Journal of Mathematical Analysis and Application,2006,323(2):844-653].展开更多
This paper is focused on the Marangoni effect in the gas-liquid mass transfer systems. A series of experiments were conducted to observe Marangoni effect by a laser Schlieren system. Experimental investigations of the...This paper is focused on the Marangoni effect in the gas-liquid mass transfer systems. A series of experiments were conducted to observe Marangoni effect by a laser Schlieren system. Experimental investigations of the occurrence of Marangoni convection were presented. The typical polygonal patterns and even the reaching of chaotic interfacial flow were observed. The visual evidences were discussed and the characteristic time and scale of Marangoni convection were obtained approximately as 0. 5 s and 1 mm according to the Schlieren images. From the perspective of hydrodynamic instability, the mechanism of the Marangoni convection was investigated. Though many external factors have influence on the interfacial instability, the local surface-tension gradient is the primary reason for the Marangoni convection. The small-scale interfacial flow increases the surface renewal rate. Consequently. due to the occurrence of the Marangoni effect, the mass transfer rate can be significantly enhanced.展开更多
The evolutionary complexity of modem media systems represents an area of research that would benefit from further description and debate. In order to better understand the challenges and considerations associated with...The evolutionary complexity of modem media systems represents an area of research that would benefit from further description and debate. In order to better understand the challenges and considerations associated with the new, constantly changing media ecology, a more holistic worldview must be catapulted to the forefront of the collective discussion. To that effect, the following essay examines the open source software movement from the philosophical perspective of Tibetan Buddhism. Using the principles of interconnectedness, impermanence, and the illusory nature of self and reality, all fundamental elements of Buddhist philosophy, this discussion provides a renewed framework for exploring the ethical implications of open sourcing. A review of Buddhist teachings, coupled with literature from foundational media theorists such as Neil Postman and Marshall and Eric McLuhan, will set the stage for contemplating the ethics of the modem information ecology, epitomized by the collaborative spirit and community connections of open source software.展开更多
Soil moisture is a key parameter in agricultural irrigation. The L band（1.58GHz） on board global position system （GPS） satellite is well suited for monitoring the change of soil moisture. In order to investigate t...Soil moisture is a key parameter in agricultural irrigation. The L band（1.58GHz） on board global position system （GPS） satellite is well suited for monitoring the change of soil moisture. In order to investigate the potential of retrieving soil moisture using the L-band GPS bistatic radar, this paper analyzed a retrieval method by using field experiment data. In order to investigate the relation- ship between the soil moisture （ corresponding roughly to the 0 - 5cm top soil layer） and the signal- to-noise ratio （PT-S-R） to the direct GPS signal-to-noise ratio （Pd_sNR）, an experiment was conducted in Hulunber grassland of China in 2009 and 2011. Six field sites in the soil moisture experiment were utilized to analyze the relationship between soil moisture and the ratio of Pr-SNR to Pd-SN~ and the square of correlation coefficient was about 0.9 when the surface type was known and the elevation angle of the satellite ranged from 65 to 85 degrees approximately. The analysis shows that ratio of Pr-SNR to Pd-SNR can be used to monitor the soil moisture, because the ratio of Pr-SVR to Pd-SNR maxi- mized the elimination of the influence of different signals from different GPS satellites. The estimation accuracy could be improved if we make full use of the empirical knowledge on elevation angles of GPS satellites and ground roughness of different surface types.展开更多
Starting from a Backlund transformation and taking a special ansatz for the function f, we can obtain a much more generalexpression of solution that includes some variable separated functions for the higher-order Broe...Starting from a Backlund transformation and taking a special ansatz for the function f, we can obtain a much more generalexpression of solution that includes some variable separated functions for the higher-order Broer-Kaup system. From this expression, we investigate the interactions of localized coherent structures such as the multi-solitonic excitations and find the novel phenomenon that their interactions have non-elastic behavior because the fission/fusion may occur after the interaction of each localized coherent structure.展开更多
Terrorism is a global phenomenon that over the last 44 years more than 140,000 terrorist events have been carried out. In the period from 1970-2001, the five countries with the largest number of terrorist attacks were...Terrorism is a global phenomenon that over the last 44 years more than 140,000 terrorist events have been carried out. In the period from 1970-2001, the five countries with the largest number of terrorist attacks were Colombia, Peru, El Salvador, United Kingdom, and India. On the other hand, in the post-2001 context, the five countries with the largest number of terrorist attacks were Iraq, Pakistan, Afghanistan, India, and Thailand. One method for measuring in an aggregate way, how many people have suffered under terrorist attacks at national level is to analyze the correlation between some national wellbeing indicators and the number of terrorist attacks. The aim of this study is to analyze empirically the correlation between the global terrorist attacks and the countries wellbeing indicators. Five indicators show a strong relationship with the number of terrorist attacks in the case of the four most attacked countries in the post-2001 context. The authors consider that their findings can support the design of new strategies for preventing terrorist activities taking into account certain socio-economic and political drivers. The authors conclude that as such drivers are socio-complex, so it is necessary to adopt the complex adaptive system （CAS） approach to provide a new way of thinking about terrorism.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.40321101 and 40071036)the Major State Basic Research Development Program of China(973 Program)(No.2002CB412503)
文摘Soil organic carbon(SOC)can act as a sink or source of atmospheric carbon dioxide;therefore,it is important to understand the amount and composition of SOC in terrestrial ecosystems,the spatial variation in SOC,and the underlying mechanisms that stabilize SOC.In this study,density fractionation and acid hydrolysis were used to assess the spatial variation in SOC,the heavy fraction of organic carbon(HFOC),and the resistant organic carbon(ROC)in soils of the southern Hulun Buir region,northeastern China,and to identify the major factors that contribute to this variation.The results showed that as the contents of clay and silt particles(0–50μm)increased,both methylene blue(MB)adsorption by soil minerals and microaggregate contents increased in the 0–20 and 20–40 cm soil layers(P<0.05).Although varying with vegetation types,SOC,HFOC,and ROC contents increased significantly with the content of clay and silt particles, MB adsorption by soil minerals,and microaggregate content(P<0.05),suggesting that soil texture,the MB adsorption by soil minerals,and microaggregate abundance might be important factors influencing the spatial heterogeneity of carbon contents in soils of the southern Hulun Buir region.
文摘A generalized Lyapunov function was employed to investigate the ultimate bound and positively invariant set of a generalized Lorenz system.We derived an ellipsoidal estimate of the ultimate bound and positively invariant set for the generalized Lorenz system,for all the positive values of system parameters a,b,and c.Our results extend the related result of Li,et al.[Li DM,Lu JA,Wu XQ,et al.,Estimating the ultimate bound and positively invariant set for the Lorenz system and a unified chaotic system,Journal of Mathematical Analysis and Application,2006,323(2):844-653].
基金Supported by National Natural Science Foundation of China(No. 20136010).
文摘This paper is focused on the Marangoni effect in the gas-liquid mass transfer systems. A series of experiments were conducted to observe Marangoni effect by a laser Schlieren system. Experimental investigations of the occurrence of Marangoni convection were presented. The typical polygonal patterns and even the reaching of chaotic interfacial flow were observed. The visual evidences were discussed and the characteristic time and scale of Marangoni convection were obtained approximately as 0. 5 s and 1 mm according to the Schlieren images. From the perspective of hydrodynamic instability, the mechanism of the Marangoni convection was investigated. Though many external factors have influence on the interfacial instability, the local surface-tension gradient is the primary reason for the Marangoni convection. The small-scale interfacial flow increases the surface renewal rate. Consequently. due to the occurrence of the Marangoni effect, the mass transfer rate can be significantly enhanced.
文摘The evolutionary complexity of modem media systems represents an area of research that would benefit from further description and debate. In order to better understand the challenges and considerations associated with the new, constantly changing media ecology, a more holistic worldview must be catapulted to the forefront of the collective discussion. To that effect, the following essay examines the open source software movement from the philosophical perspective of Tibetan Buddhism. Using the principles of interconnectedness, impermanence, and the illusory nature of self and reality, all fundamental elements of Buddhist philosophy, this discussion provides a renewed framework for exploring the ethical implications of open sourcing. A review of Buddhist teachings, coupled with literature from foundational media theorists such as Neil Postman and Marshall and Eric McLuhan, will set the stage for contemplating the ethics of the modem information ecology, epitomized by the collaborative spirit and community connections of open source software.
基金Supported by the National Key Basic Research Program of China(No.2010CB951503,2013BAC03B00)
文摘Soil moisture is a key parameter in agricultural irrigation. The L band（1.58GHz） on board global position system （GPS） satellite is well suited for monitoring the change of soil moisture. In order to investigate the potential of retrieving soil moisture using the L-band GPS bistatic radar, this paper analyzed a retrieval method by using field experiment data. In order to investigate the relation- ship between the soil moisture （ corresponding roughly to the 0 - 5cm top soil layer） and the signal- to-noise ratio （PT-S-R） to the direct GPS signal-to-noise ratio （Pd_sNR）, an experiment was conducted in Hulunber grassland of China in 2009 and 2011. Six field sites in the soil moisture experiment were utilized to analyze the relationship between soil moisture and the ratio of Pr-SNR to Pd-SN~ and the square of correlation coefficient was about 0.9 when the surface type was known and the elevation angle of the satellite ranged from 65 to 85 degrees approximately. The analysis shows that ratio of Pr-SNR to Pd-SNR can be used to monitor the soil moisture, because the ratio of Pr-SVR to Pd-SNR maxi- mized the elimination of the influence of different signals from different GPS satellites. The estimation accuracy could be improved if we make full use of the empirical knowledge on elevation angles of GPS satellites and ground roughness of different surface types.
文摘Starting from a Backlund transformation and taking a special ansatz for the function f, we can obtain a much more generalexpression of solution that includes some variable separated functions for the higher-order Broer-Kaup system. From this expression, we investigate the interactions of localized coherent structures such as the multi-solitonic excitations and find the novel phenomenon that their interactions have non-elastic behavior because the fission/fusion may occur after the interaction of each localized coherent structure.
文摘Terrorism is a global phenomenon that over the last 44 years more than 140,000 terrorist events have been carried out. In the period from 1970-2001, the five countries with the largest number of terrorist attacks were Colombia, Peru, El Salvador, United Kingdom, and India. On the other hand, in the post-2001 context, the five countries with the largest number of terrorist attacks were Iraq, Pakistan, Afghanistan, India, and Thailand. One method for measuring in an aggregate way, how many people have suffered under terrorist attacks at national level is to analyze the correlation between some national wellbeing indicators and the number of terrorist attacks. The aim of this study is to analyze empirically the correlation between the global terrorist attacks and the countries wellbeing indicators. Five indicators show a strong relationship with the number of terrorist attacks in the case of the four most attacked countries in the post-2001 context. The authors consider that their findings can support the design of new strategies for preventing terrorist activities taking into account certain socio-economic and political drivers. The authors conclude that as such drivers are socio-complex, so it is necessary to adopt the complex adaptive system （CAS） approach to provide a new way of thinking about terrorism.
