The intermolecular clusters of sulfur dioxide with water, SO2（H2O）n （n = 2～5）, are studied by using B3LYP density functional theory and MP2 ab initio methods along with the large basis sets （6-311＋＋G（d,p） an...The intermolecular clusters of sulfur dioxide with water, SO2（H2O）n （n = 2～5）, are studied by using B3LYP density functional theory and MP2 ab initio methods along with the large basis sets （6-311＋＋G（d,p） and aug-cc-pVDZ）. The equilibrium geometries, intermolecular binding energies, and anharmonic frequencies of the clusters are calculated and compared with those of pure water clusters and available experiments. SO2 tends to form cyclic hydrogen-bonded complexes with two or three water molecules. In the larger clusters, however, water molecules begin to retain the structure of pure water clusters and segregate from SO2. Infrared absorption assignments for the small clusters are discussed to resolve a possible incorrect assignment in a recent spectroscopic experiment on the clusters.展开更多
The study was conducted to determine the socioeconomic impact two (2) Small Water Impounding Projects (SWIPs) namely Burgos SWIP in Cabarroguis and Divisoria Norte SWIP in Maddela, both in the Province of Quirino, Phi...The study was conducted to determine the socioeconomic impact two (2) Small Water Impounding Projects (SWIPs) namely Burgos SWIP in Cabarroguis and Divisoria Norte SWIP in Maddela, both in the Province of Quirino, Philippines. The study made use of structured questionnaire to gather the socio-demographic profile and determined the socioeconomic impact of the SWIPs to the farmer-beneficiaries. Most of the farmer-beneficiaries of Burgos and Divisoria Norte SWIPs are male, 40 - 59 years old, married, have below four household members, Roman Catholic, high school graduates and some are members of cooperatives. They are rice farmers, and have attended one to two training courses related to farming and own a 1.00 to 1.99 hectares farm. “Utilization of water in the reservoir for other purposes like wallowing pool for carabaos” and “integration of fish production and livestock raising” were the identified benefits at the farmer’s level while “introduction of new techniques in farming by the Local Government Units,” “availability of cheap fish and additional income as a result of integration of fish production” and “construction of better roads” were the identified benefits at the community level. The SWIPs have positive impact as confirmed by the increase in the annual mean yield and in the annual gross income of the farmer-beneficiaries. It contributed a significant increase of 2.14 tons/year in the mean yield generating an additional income of PhP 32,113.64 for Burgos SWIP. On the other hand, it contributed a significant increase of 2.08 tons/year giving an additional income of PhP 31,313.60 for Divisoria Norte farmer-beneficiaries. The result of this study will provide strategic information to policy makers of agricultural and irrigation agencies on the existing weaknesses of irrigation systems in the country and determine in a more quantifiable terms level of potential improvement and investment targets.展开更多
The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to d...The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to direct threats to national food security and regional sustainable development. Therefore, it is necessary to summarize integrated prevention and control experience of small watersheds in black soil region of Northeast China. Tongshuang small watershed, a typical watershed in rolling hills of typical black soil areas in Northeast China, is selected as the study area. Based on nearly 50 years' experience in prevention and control of soil and water loss, the structures and overall benefits of an integrated prevention and control system for soil and water loss are investigated. Then, the 'three defense lines' tri-dimensional protection system with reasonable allocation of different types of soil and water control measures from the hill top to gully is systematically analyzed. The first line on the top hill can weaken and block uphill runoff and sediment, hold water resources and improve soil property. The second line on the hill can truncate slope length, slow down the runoff velocity and reduce erosion energy. The third line in the gully is mainly composed of waterfall engineering, which can inhibit soil erosion and restore land resources. The 'three defense lines' system is feasible for soil and water loss control of small watersheds in the typical black soil region of Northeast China. Through the application of the in Tongshuang small watershed, There are effective improvements in ecological conditions in Tongshuang small watershed after the application of 'three defense lines' soil and water control system. Moreover, the integrated treatment paradigm for soil and water loss in typical black soil region is compared with that in loess region. The results of this study could offer references and experiences for other small watersheds in typical black soil region of Northeast China.展开更多
Seasonal variability in source water can lead to challenges for drinking water providers related to operational optimization and process control in treatment facilities. The objective of this study is to investigate s...Seasonal variability in source water can lead to challenges for drinking water providers related to operational optimization and process control in treatment facilities. The objective of this study is to investigate seasonal variability of water quality in municipal small water systems （〈 3000 residents） supplied by surface waters. Residual chlorine and trihalomethanes （THM） were measured over seven years （2003-2009）. Comparisons are made within each system over time, as well as between systems according to the type of their treatment technologies. THM concentrations are generally higher in the summer and autumn. The seasonal variability was generally more pronounced in systems using chlorination plus additional treatment. Chloroform, total THM （TTHM） and residual chlorine concentrations were generally lower in systems using chlorination plus additional treatment. Conversely, brominated THM concentrations were higher in systems using additional treatment. Residual chlorine was highest in the winter and lowest in the spring and summer. Seasonal variations were most pronounced for residual chlorine in systems with additional treatment. There was generally poor correlation between THM concentrations and concentrations of residual chlorine. Further study with these data will be beneficial in finding determinants and indicators for both quantity and variability of disinfection byproducts and other water quality parameters.展开更多
基金supported by the National Natural Science Foundation of China (20528706)the China Postdoctoral Science Foundation (20090450385)
文摘The intermolecular clusters of sulfur dioxide with water, SO2（H2O）n （n = 2～5）, are studied by using B3LYP density functional theory and MP2 ab initio methods along with the large basis sets （6-311＋＋G（d,p） and aug-cc-pVDZ）. The equilibrium geometries, intermolecular binding energies, and anharmonic frequencies of the clusters are calculated and compared with those of pure water clusters and available experiments. SO2 tends to form cyclic hydrogen-bonded complexes with two or three water molecules. In the larger clusters, however, water molecules begin to retain the structure of pure water clusters and segregate from SO2. Infrared absorption assignments for the small clusters are discussed to resolve a possible incorrect assignment in a recent spectroscopic experiment on the clusters.
文摘The study was conducted to determine the socioeconomic impact two (2) Small Water Impounding Projects (SWIPs) namely Burgos SWIP in Cabarroguis and Divisoria Norte SWIP in Maddela, both in the Province of Quirino, Philippines. The study made use of structured questionnaire to gather the socio-demographic profile and determined the socioeconomic impact of the SWIPs to the farmer-beneficiaries. Most of the farmer-beneficiaries of Burgos and Divisoria Norte SWIPs are male, 40 - 59 years old, married, have below four household members, Roman Catholic, high school graduates and some are members of cooperatives. They are rice farmers, and have attended one to two training courses related to farming and own a 1.00 to 1.99 hectares farm. “Utilization of water in the reservoir for other purposes like wallowing pool for carabaos” and “integration of fish production and livestock raising” were the identified benefits at the farmer’s level while “introduction of new techniques in farming by the Local Government Units,” “availability of cheap fish and additional income as a result of integration of fish production” and “construction of better roads” were the identified benefits at the community level. The SWIPs have positive impact as confirmed by the increase in the annual mean yield and in the annual gross income of the farmer-beneficiaries. It contributed a significant increase of 2.14 tons/year in the mean yield generating an additional income of PhP 32,113.64 for Burgos SWIP. On the other hand, it contributed a significant increase of 2.08 tons/year giving an additional income of PhP 31,313.60 for Divisoria Norte farmer-beneficiaries. The result of this study will provide strategic information to policy makers of agricultural and irrigation agencies on the existing weaknesses of irrigation systems in the country and determine in a more quantifiable terms level of potential improvement and investment targets.
基金Supported by the National Natural Science Foundation of China,Science Foundation for Youths ( 41001165,40901133,30901163)
文摘The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to direct threats to national food security and regional sustainable development. Therefore, it is necessary to summarize integrated prevention and control experience of small watersheds in black soil region of Northeast China. Tongshuang small watershed, a typical watershed in rolling hills of typical black soil areas in Northeast China, is selected as the study area. Based on nearly 50 years' experience in prevention and control of soil and water loss, the structures and overall benefits of an integrated prevention and control system for soil and water loss are investigated. Then, the 'three defense lines' tri-dimensional protection system with reasonable allocation of different types of soil and water control measures from the hill top to gully is systematically analyzed. The first line on the top hill can weaken and block uphill runoff and sediment, hold water resources and improve soil property. The second line on the hill can truncate slope length, slow down the runoff velocity and reduce erosion energy. The third line in the gully is mainly composed of waterfall engineering, which can inhibit soil erosion and restore land resources. The 'three defense lines' system is feasible for soil and water loss control of small watersheds in the typical black soil region of Northeast China. Through the application of the in Tongshuang small watershed, There are effective improvements in ecological conditions in Tongshuang small watershed after the application of 'three defense lines' soil and water control system. Moreover, the integrated treatment paradigm for soil and water loss in typical black soil region is compared with that in loess region. The results of this study could offer references and experiences for other small watersheds in typical black soil region of Northeast China.
文摘Seasonal variability in source water can lead to challenges for drinking water providers related to operational optimization and process control in treatment facilities. The objective of this study is to investigate seasonal variability of water quality in municipal small water systems （〈 3000 residents） supplied by surface waters. Residual chlorine and trihalomethanes （THM） were measured over seven years （2003-2009）. Comparisons are made within each system over time, as well as between systems according to the type of their treatment technologies. THM concentrations are generally higher in the summer and autumn. The seasonal variability was generally more pronounced in systems using chlorination plus additional treatment. Chloroform, total THM （TTHM） and residual chlorine concentrations were generally lower in systems using chlorination plus additional treatment. Conversely, brominated THM concentrations were higher in systems using additional treatment. Residual chlorine was highest in the winter and lowest in the spring and summer. Seasonal variations were most pronounced for residual chlorine in systems with additional treatment. There was generally poor correlation between THM concentrations and concentrations of residual chlorine. Further study with these data will be beneficial in finding determinants and indicators for both quantity and variability of disinfection byproducts and other water quality parameters.
