A new kinetic-spectrophotometric method is proposed for the determination of copper (Ⅱ). The method is based on the catalytic effect of copper (Ⅱ) on the oxidation of weak acid brilliant blue dye (RAWL) by hydrogen ...A new kinetic-spectrophotometric method is proposed for the determination of copper (Ⅱ). The method is based on the catalytic effect of copper (Ⅱ) on the oxidation of weak acid brilliant blue dye (RAWL) by hydrogen peroxide. The copper (Ⅱ) can be determined spectrophotometrically by measuring the decrease of absorbance of RAWL at λ = 626 nm using the fix-time method. The optimum reaction conditions are as follows: pH 7.20, buffer solution NaOH-KH2PO4, RAWL (200 mg L-1) 5.00 mL, H2O2 (30%) 0.50 mL, reaction temperature 80℃ and reaction time 20 min. The linear range of this method is between 0 μg L-1 and 12 μg L-1 and the limit of detection is 0.011 μg L-1, the relative standard deviation (RSD) in five replicate determinations for 2 and 8 μg L-1 copper (Ⅱ) are 3.2% and 2.3%, respectively. Twenty ions do not interfere in the determination of copper (Ⅱ). The method has been applied satisfactorily to the determination of copper (Ⅱ) in freshwater samples (tap water and Yellow River water from Lijin, Shandong, China) and seawater samples (from the South China Sea), the recovery rates are 98.0%, 102.5% and 96.0%, respectively.展开更多
In 2010, the debate over valuation of the Renminbi is again heating up and the Chinese currency has returned to appreciating against the dollar But is the Renminbi undervalued？ Drawing on the Balassa-Samuelson （B-S...In 2010, the debate over valuation of the Renminbi is again heating up and the Chinese currency has returned to appreciating against the dollar But is the Renminbi undervalued？ Drawing on the Balassa-Samuelson （B-S） effect on purchasing power parity, we conduct theoretical and empirical analyses of this issue. Theoretical analysis proves that a country＇s real exchange rate will appreciate with rising income, but the currencies of low-income countries tend to be undervalued. In order to avoid biased conclusions resulting from a single dataset or sampling method, we draw on three major publicly-available datasets to examine the B-S effect across 144 economies. Our results indicate that the degree of Renminbi misvaluation is highly dependent on the data source. Synthesizing analyses of diverse datasets, we estimate that the Renminbi was only undervalued by less than 8per cent in 2009. We conclude that China＇s external imbalance most probably results from deep-seated structural imbalances rather than Renminbi undervaluation.展开更多
A data processing method was proposed for eliminating the end restraint in triaxial tests of soil. A digital image processing method was used to calculate the local deformations and local stresses for any region on th...A data processing method was proposed for eliminating the end restraint in triaxial tests of soil. A digital image processing method was used to calculate the local deformations and local stresses for any region on the surface of triaxial soil specimens. The principle and implementation of this digital image processing method were introduced as well as the calculation method for local mechanical properties of soil specimens. Comparisons were made between the test results calculated by the data from both the entire specimen and local regions, and it was found that the deformations were more uniform in the middle region compared with the entire specimen. In order to quantify the nonuniform characteristic of deformation, the non-uniformity coefficients of strain were defined and calculated. Traditional and end-lubricated triaxial tests were conducted under the same condition to investigate the effects of using local region data for deformation calculation on eliminating the end restraint of specimens. After the statistical analysis of all test results, it was concluded that for the tested soil specimen with the size of 39.1 mm × 80 ram, the utilization of the middle 35 mm region of traditional specimens in data processing had a better effect on eliminating end restraint compared with end lubrication. Furthermore, the local data analysis in this paper was validated through the comparisons with the test results from other researchers.展开更多
Climate events pose major challenges to food production and the livelihoods of rural inhabitants in northern Laos, where upland rice using swidden production is an important crop. The onset of the rainy season in this...Climate events pose major challenges to food production and the livelihoods of rural inhabitants in northern Laos, where upland rice using swidden production is an important crop. The onset of the rainy season in this area is one such climate event, and it has occurred earlier and with less regularity in recent years. Not all households are able to cope with these changes. This study examines the ability of local farmers to cope with rice insufficiency. This investigation also clarifies household strategies in dealing with the climate event. We randomly interviewed 63 of 95 household heads, and performed a paired sample t test to examine the significance of differences in three household groups between the 2010 normal climate and the 2011 climate event. The groups were categorized according to rice selfsufficiency in 2011: groups I are households with rice self-sufficiency, group II are those facing a rice shortage of up to 3 months, and group III are those with insufficient rice for over 3 months. We also conducted a one-way ANOVA to examine the significance of differences in livelihood strategies among the three groups. We found that the household labor force was the most important factor in enhancing the villagers' ability to deal with the climate event and that the level of impact of that event shaped their coping strategies. Households with substantial labor force had more options for coping strategies than those with smaller ones. The villagers faced different levels of impact and adopted differentcoping strategies accordingly. Non-timber forest product collection was the principle livelihood strategy in response to non-climate factors such as education, access to health services, provision of equipment and clothing, and overcoming the impact of the climate event. Households heavily affected by the early rainy season onset tended to engage in intensive activities such as off-farm activity and outside work, rather than their major livelihood activities in the village(upland crop and livestock production).展开更多
文摘A new kinetic-spectrophotometric method is proposed for the determination of copper (Ⅱ). The method is based on the catalytic effect of copper (Ⅱ) on the oxidation of weak acid brilliant blue dye (RAWL) by hydrogen peroxide. The copper (Ⅱ) can be determined spectrophotometrically by measuring the decrease of absorbance of RAWL at λ = 626 nm using the fix-time method. The optimum reaction conditions are as follows: pH 7.20, buffer solution NaOH-KH2PO4, RAWL (200 mg L-1) 5.00 mL, H2O2 (30%) 0.50 mL, reaction temperature 80℃ and reaction time 20 min. The linear range of this method is between 0 μg L-1 and 12 μg L-1 and the limit of detection is 0.011 μg L-1, the relative standard deviation (RSD) in five replicate determinations for 2 and 8 μg L-1 copper (Ⅱ) are 3.2% and 2.3%, respectively. Twenty ions do not interfere in the determination of copper (Ⅱ). The method has been applied satisfactorily to the determination of copper (Ⅱ) in freshwater samples (tap water and Yellow River water from Lijin, Shandong, China) and seawater samples (from the South China Sea), the recovery rates are 98.0%, 102.5% and 96.0%, respectively.
文摘In 2010, the debate over valuation of the Renminbi is again heating up and the Chinese currency has returned to appreciating against the dollar But is the Renminbi undervalued？ Drawing on the Balassa-Samuelson （B-S） effect on purchasing power parity, we conduct theoretical and empirical analyses of this issue. Theoretical analysis proves that a country＇s real exchange rate will appreciate with rising income, but the currencies of low-income countries tend to be undervalued. In order to avoid biased conclusions resulting from a single dataset or sampling method, we draw on three major publicly-available datasets to examine the B-S effect across 144 economies. Our results indicate that the degree of Renminbi misvaluation is highly dependent on the data source. Synthesizing analyses of diverse datasets, we estimate that the Renminbi was only undervalued by less than 8per cent in 2009. We conclude that China＇s external imbalance most probably results from deep-seated structural imbalances rather than Renminbi undervaluation.
基金Supported by Major State Basic Research Development Program of China("973" Program,No.2010CB731502)
文摘A data processing method was proposed for eliminating the end restraint in triaxial tests of soil. A digital image processing method was used to calculate the local deformations and local stresses for any region on the surface of triaxial soil specimens. The principle and implementation of this digital image processing method were introduced as well as the calculation method for local mechanical properties of soil specimens. Comparisons were made between the test results calculated by the data from both the entire specimen and local regions, and it was found that the deformations were more uniform in the middle region compared with the entire specimen. In order to quantify the nonuniform characteristic of deformation, the non-uniformity coefficients of strain were defined and calculated. Traditional and end-lubricated triaxial tests were conducted under the same condition to investigate the effects of using local region data for deformation calculation on eliminating the end restraint of specimens. After the statistical analysis of all test results, it was concluded that for the tested soil specimen with the size of 39.1 mm × 80 ram, the utilization of the middle 35 mm region of traditional specimens in data processing had a better effect on eliminating end restraint compared with end lubrication. Furthermore, the local data analysis in this paper was validated through the comparisons with the test results from other researchers.
基金funded by Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research (Kakenhi), Scientific Research (A)
文摘Climate events pose major challenges to food production and the livelihoods of rural inhabitants in northern Laos, where upland rice using swidden production is an important crop. The onset of the rainy season in this area is one such climate event, and it has occurred earlier and with less regularity in recent years. Not all households are able to cope with these changes. This study examines the ability of local farmers to cope with rice insufficiency. This investigation also clarifies household strategies in dealing with the climate event. We randomly interviewed 63 of 95 household heads, and performed a paired sample t test to examine the significance of differences in three household groups between the 2010 normal climate and the 2011 climate event. The groups were categorized according to rice selfsufficiency in 2011: groups I are households with rice self-sufficiency, group II are those facing a rice shortage of up to 3 months, and group III are those with insufficient rice for over 3 months. We also conducted a one-way ANOVA to examine the significance of differences in livelihood strategies among the three groups. We found that the household labor force was the most important factor in enhancing the villagers' ability to deal with the climate event and that the level of impact of that event shaped their coping strategies. Households with substantial labor force had more options for coping strategies than those with smaller ones. The villagers faced different levels of impact and adopted differentcoping strategies accordingly. Non-timber forest product collection was the principle livelihood strategy in response to non-climate factors such as education, access to health services, provision of equipment and clothing, and overcoming the impact of the climate event. Households heavily affected by the early rainy season onset tended to engage in intensive activities such as off-farm activity and outside work, rather than their major livelihood activities in the village(upland crop and livestock production).
