Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake via nitrite was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor((AO)2 SBR). The system showed ...Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake via nitrite was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor((AO)2 SBR). The system showed stable phosphorus and nitrogen removal performance, and average removals for COD, TN and TP were 90%, 91% and 96%, respectively. The conditions of pH 7.5—8.0 and temperature 32℃ were found detrimental to nitrite oxidation bacteria but favorable to ammonia oxidizers, and the corresponding specific oxygen uptake rates(SOUR) for phase 1 and 2 of nitrification process were 0.7 and 15 mgO 2/(gVSS·h) in respect, which led to the nitrite accumulation in aerobic phase of(AO)2 SBR. Respiratory tests showed that 40 mgNO 2-N/L did not deteriorate the sludge activity drastically, and it implied that exposure of sludge to nitrite periodically enabled the biomass to have more tolerance capacity to resist the restraining effects from nitrite. In addition, batch tests were carried out and verified that denitrifying phosphorus accumulation organisms(DPAOs) could be enriched in a single sludge system coexisting with nitrifiers by introducing an anoxic phase in an anaerobic-aerobic SBR, and the ratio of the anoxic phosphate uptake capacity to aerobic phosphate uptake capacity was 45%. It was also found that nitrite(up to 20 mgNO 2-N/L) was not inhibitory to anoxic phosphate uptake and could serve as an electron acceptor like nitrate, but presented poorer efficiency compared with nitrate.展开更多
Soil organic carbon (SOC) was considered to be a key index in evaluation of soil degradation and soil C sequestration. To discuss the spatial-temporal dynamics of SOC in arable layer in reversed desertification area, ...Soil organic carbon (SOC) was considered to be a key index in evaluation of soil degradation and soil C sequestration. To discuss the spatial-temporal dynamics of SOC in arable layer in reversed desertification area, a case study was conducted in Yulin City, Shaanxi Province, China. Data of SOC were based on general soil survey in 1982 and repeated soil sampling in 2003. Soil organic carbon content (SOCC) was determined by K2Cr3O7-FeSO4 titration method, and soil organic carbon density (SOCD) was calculated by arithmetic average and area weighted average method, respectively. On average, SOCC and SOCD of the arable layer in the study area from 1982 to 2003 had increased 0.51g/kg and 0.16kg/m2, respectively. Considering main soil types, the widest distributed Arid-Sandic Entisols had lowest values and increments of SOCC and SOCD during the study period; while the second widest Los-Orthic Entisols had higher values and increments of SOCC and SOCD, compared to the mean values of the whole region. The results indicated that reversed desertification process was due to the modification of land use and management practices, such as natural vegetation recovery, planting grass, turning arable land to grassland, and soil and water conservation etc., which can improve SOCC and SOCD and thus enhance soil C sequestration.展开更多
Four hundred and six food samples of 64 ha items, as well as 19 samples of aluminum(Al) containing food additives, were collected from Guangdong, Hunan, Shanghai andBeijing, and their Al contents were deterndned. The ...Four hundred and six food samples of 64 ha items, as well as 19 samples of aluminum(Al) containing food additives, were collected from Guangdong, Hunan, Shanghai andBeijing, and their Al contents were deterndned. The migration of Al from cookingaluminium-utensils into foods was also studied. The results show that the average dailydietary intake of Al in Chinese population was 9-12 mp. The dietary intake of migratedA1 from Al-containing cooking utensils was apPfoximately 4 mg per person per day.However, the use of Al containing fbod additives in thc preParation of certain wheatflour products (e.g. steamed bread, deepfried dough sticks) caused significant increase ofdietary Al intake (> 1 mg/hoay, the ADI Propeed by WHQ) It is suggested that thecontent of Al in wheat flour products should not exceed 100 mghg, in order to meet theWHO ADI.展开更多
The strength and deformation characteristics of sedimentary soft rock evaluated in relation to several large-scale researc and construction projects in Japan are reviewed.The elastic stiffiness at small non-linearity ...The strength and deformation characteristics of sedimentary soft rock evaluated in relation to several large-scale researc and construction projects in Japan are reviewed.The elastic stiffiness at small non-linearity due to strain and pressure level,and viscous properties are described.The elastic stiffness from triaxial tests using high-quality core samples while measuring stresses and strains accurately is basically the same as the corresponding value from field shear wave velocity.It is necessary to take into account the dependency or stiffness on shear and pressure level,which could be evaluated by relevant laboratory stress-strain tests while referring to results trom relevant field loading tests.Loading rate effects due to the material viscous properties could be simulated by a non-linear three-component model.展开更多
In Wuxi Wastewater Treatment Plant, the Anaerobic, anoxic and oxic (A2/O) process was employed to remove the nitrogen and phosphorus, which exhibited the positive results of the high removal efficiency for phosphorus ...In Wuxi Wastewater Treatment Plant, the Anaerobic, anoxic and oxic (A2/O) process was employed to remove the nitrogen and phosphorus, which exhibited the positive results of the high removal efficiency for phosphorus with a range of 67.7% to 89.9% and an average value of 78.0. The effluent of phosphorus met the national discharge standard. The removal of TN was effected by both BOD variation of influent and wastewater temperature. TN removal was in the range of 28.5% to 55.8% with an average value of 39.4%. The energy cost was 0.15 kWh(m3d)-1 or 1.35 kWh(kgBOD@d)-1. The annual average sludge production was 46.3 m3d-1, the annual average dosage for the dewatering was 40 kg d-1 .展开更多
In order to research the changing process of the pollution from the formation of Nansihu Lake, this study determined the isotope age and depositional rate and analyzed the organic geo-chem...In order to research the changing process of the pollution from the formation of Nansihu Lake, this study determined the isotope age and depositional rate and analyzed the organic geo-chemical quotas and heavy metal quotas of two sedimentary profiles of Weishan and Dushan lakes. Research results showed that from the formation of Nansihu Lake, the change of the pollution could be divided into four phrases. At the early phrase of the formation, the organic matters of the lake mainly derived from the exotic matters and had a close relation to the effect on the water and sands from the Huanghe (Yellow) River. At the middle and late phrases of the development, the endogenous matters of the lake became the main and stable source of the organic matters. The overflow of the Huanghe River, the excavation of the Grand Canal and the cut of trees caused the changes of the historic pollution. In recent 20 years, the modern industrial pollution from the organic matters and heavy metals has an increasingly heavy tendency.展开更多
A class of chaotic map called piecewise-quadratic-equation map to design feedback stream cipher is proposed. Such map can generate chaotic signals that have uniform distribution function, δ-like autocorrelation funct...A class of chaotic map called piecewise-quadratic-equation map to design feedback stream cipher is proposed. Such map can generate chaotic signals that have uniform distribution function, δ-like autocorrelation function. Compared with the piecewise-linear map, this map provides enhanced security in that they can maintain the original perfect statistical properties, as well as overcome the defect of piecewise-linearity and expand the key space. This paper presents a scheme to improve the local complexity of the chaotic stream cipher based on the piecewise-quadratic-equationmap. Both the theoretic analysis and the results of simulation show that this scheme improves the microstructure of the phase-space graph on condition that the good properties of the original scheme are remained.展开更多
Objective: to understand the effect of mental health care in hypertensive patients. Methods: in this study, 268 medical hypertensive patients from January 2021 to December 2021 were divided into two groups according t...Objective: to understand the effect of mental health care in hypertensive patients. Methods: in this study, 268 medical hypertensive patients from January 2021 to December 2021 were divided into two groups according to the nursing method: normal control group and control group, 134 patients per group. At the same time of daily care, strengthen the health education of patients, and compare the cure rates of patients in the two wards. Results: the control groups comprehensive grasp of hypertension was 39.55%, which was significantly lower than the control groups 70.15% (P<0.05). Conclusion: the application of strengthening health education in medical nursing of hypertensive patients has a positive impact on improving patients treatment compliance and enhancing patients health awareness, and has clinical significance and value.展开更多
文摘Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake via nitrite was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor((AO)2 SBR). The system showed stable phosphorus and nitrogen removal performance, and average removals for COD, TN and TP were 90%, 91% and 96%, respectively. The conditions of pH 7.5—8.0 and temperature 32℃ were found detrimental to nitrite oxidation bacteria but favorable to ammonia oxidizers, and the corresponding specific oxygen uptake rates(SOUR) for phase 1 and 2 of nitrification process were 0.7 and 15 mgO 2/(gVSS·h) in respect, which led to the nitrite accumulation in aerobic phase of(AO)2 SBR. Respiratory tests showed that 40 mgNO 2-N/L did not deteriorate the sludge activity drastically, and it implied that exposure of sludge to nitrite periodically enabled the biomass to have more tolerance capacity to resist the restraining effects from nitrite. In addition, batch tests were carried out and verified that denitrifying phosphorus accumulation organisms(DPAOs) could be enriched in a single sludge system coexisting with nitrifiers by introducing an anoxic phase in an anaerobic-aerobic SBR, and the ratio of the anoxic phosphate uptake capacity to aerobic phosphate uptake capacity was 45%. It was also found that nitrite(up to 20 mgNO 2-N/L) was not inhibitory to anoxic phosphate uptake and could serve as an electron acceptor like nitrate, but presented poorer efficiency compared with nitrate.
基金Under the auspices of International Key Project of Technological Cooperation (No. 2001DFDF0004)
文摘Soil organic carbon (SOC) was considered to be a key index in evaluation of soil degradation and soil C sequestration. To discuss the spatial-temporal dynamics of SOC in arable layer in reversed desertification area, a case study was conducted in Yulin City, Shaanxi Province, China. Data of SOC were based on general soil survey in 1982 and repeated soil sampling in 2003. Soil organic carbon content (SOCC) was determined by K2Cr3O7-FeSO4 titration method, and soil organic carbon density (SOCD) was calculated by arithmetic average and area weighted average method, respectively. On average, SOCC and SOCD of the arable layer in the study area from 1982 to 2003 had increased 0.51g/kg and 0.16kg/m2, respectively. Considering main soil types, the widest distributed Arid-Sandic Entisols had lowest values and increments of SOCC and SOCD during the study period; while the second widest Los-Orthic Entisols had higher values and increments of SOCC and SOCD, compared to the mean values of the whole region. The results indicated that reversed desertification process was due to the modification of land use and management practices, such as natural vegetation recovery, planting grass, turning arable land to grassland, and soil and water conservation etc., which can improve SOCC and SOCD and thus enhance soil C sequestration.
文摘Four hundred and six food samples of 64 ha items, as well as 19 samples of aluminum(Al) containing food additives, were collected from Guangdong, Hunan, Shanghai andBeijing, and their Al contents were deterndned. The migration of Al from cookingaluminium-utensils into foods was also studied. The results show that the average dailydietary intake of Al in Chinese population was 9-12 mp. The dietary intake of migratedA1 from Al-containing cooking utensils was apPfoximately 4 mg per person per day.However, the use of Al containing fbod additives in thc preParation of certain wheatflour products (e.g. steamed bread, deepfried dough sticks) caused significant increase ofdietary Al intake (> 1 mg/hoay, the ADI Propeed by WHQ) It is suggested that thecontent of Al in wheat flour products should not exceed 100 mghg, in order to meet theWHO ADI.
文摘The strength and deformation characteristics of sedimentary soft rock evaluated in relation to several large-scale researc and construction projects in Japan are reviewed.The elastic stiffiness at small non-linearity due to strain and pressure level,and viscous properties are described.The elastic stiffness from triaxial tests using high-quality core samples while measuring stresses and strains accurately is basically the same as the corresponding value from field shear wave velocity.It is necessary to take into account the dependency or stiffness on shear and pressure level,which could be evaluated by relevant laboratory stress-strain tests while referring to results trom relevant field loading tests.Loading rate effects due to the material viscous properties could be simulated by a non-linear three-component model.
文摘In Wuxi Wastewater Treatment Plant, the Anaerobic, anoxic and oxic (A2/O) process was employed to remove the nitrogen and phosphorus, which exhibited the positive results of the high removal efficiency for phosphorus with a range of 67.7% to 89.9% and an average value of 78.0. The effluent of phosphorus met the national discharge standard. The removal of TN was effected by both BOD variation of influent and wastewater temperature. TN removal was in the range of 28.5% to 55.8% with an average value of 39.4%. The energy cost was 0.15 kWh(m3d)-1 or 1.35 kWh(kgBOD@d)-1. The annual average sludge production was 46.3 m3d-1, the annual average dosage for the dewatering was 40 kg d-1 .
文摘In order to research the changing process of the pollution from the formation of Nansihu Lake, this study determined the isotope age and depositional rate and analyzed the organic geo-chemical quotas and heavy metal quotas of two sedimentary profiles of Weishan and Dushan lakes. Research results showed that from the formation of Nansihu Lake, the change of the pollution could be divided into four phrases. At the early phrase of the formation, the organic matters of the lake mainly derived from the exotic matters and had a close relation to the effect on the water and sands from the Huanghe (Yellow) River. At the middle and late phrases of the development, the endogenous matters of the lake became the main and stable source of the organic matters. The overflow of the Huanghe River, the excavation of the Grand Canal and the cut of trees caused the changes of the historic pollution. In recent 20 years, the modern industrial pollution from the organic matters and heavy metals has an increasingly heavy tendency.
文摘A class of chaotic map called piecewise-quadratic-equation map to design feedback stream cipher is proposed. Such map can generate chaotic signals that have uniform distribution function, δ-like autocorrelation function. Compared with the piecewise-linear map, this map provides enhanced security in that they can maintain the original perfect statistical properties, as well as overcome the defect of piecewise-linearity and expand the key space. This paper presents a scheme to improve the local complexity of the chaotic stream cipher based on the piecewise-quadratic-equationmap. Both the theoretic analysis and the results of simulation show that this scheme improves the microstructure of the phase-space graph on condition that the good properties of the original scheme are remained.
文摘Objective: to understand the effect of mental health care in hypertensive patients. Methods: in this study, 268 medical hypertensive patients from January 2021 to December 2021 were divided into two groups according to the nursing method: normal control group and control group, 134 patients per group. At the same time of daily care, strengthen the health education of patients, and compare the cure rates of patients in the two wards. Results: the control groups comprehensive grasp of hypertension was 39.55%, which was significantly lower than the control groups 70.15% (P<0.05). Conclusion: the application of strengthening health education in medical nursing of hypertensive patients has a positive impact on improving patients treatment compliance and enhancing patients health awareness, and has clinical significance and value.
