To ensure the control of the precision of air-fuel ratio(AFR)of port fuel injection(PFI)spark ignition(SI)engines,a chaos radial basis function(RBF)neural network is used to predict the air intake flow of the engine.T...To ensure the control of the precision of air-fuel ratio(AFR)of port fuel injection(PFI)spark ignition(SI)engines,a chaos radial basis function(RBF)neural network is used to predict the air intake flow of the engine.The data of air intake flow is proved to be multidimensionally nonlinear and chaotic.The RBF neural network is used to train the reconstructed phase space of the data.The chaos algorithm is employed to optimize the weights of output layer connection and the radial basis center of Gaussian function in hidden layer.The simulation results obtained from Matlab/Simulink illustrate that the model has higher accuracy compared to the conventional RBF model.The mean absolute error and the mean relative error of the chaos RBF model can reach 0.0017 and 0.48,respectively.展开更多
Exact simulation of the acoustic performance is essential to the engineering application for a vehicle intake system. The rectangular-pulse method based on the computational fluid dynamics approach was employed for ca...Exact simulation of the acoustic performance is essential to the engineering application for a vehicle intake system. The rectangular-pulse method based on the computational fluid dynamics approach was employed for calculating the transmission loss. Firstly, the transmission loss of the single-cavity element was simulated without any airflow, and the effects of different structural parameters on the acoustic performance were investigated comprehensively. Secondly, the static transmission loss of the perforated intake pipe was obtained by the rectangular-pulse method, which is proved to be accurate enough compared with the result by finite element method. Thirdly, under the different conditions of the mean airflow and the operating temperature, the specific transmission loss was acquired respectively. In general, the peaks of the transmission loss are shifted to the lower frequency range because of the reverse airflow, but the amplitudes are irregularly changed. Besides, when the operating temperature increases, the peaks are shifted to the higher frequencies. Finally, with the designed perforated pipe installed to the intake system, the road tests were proceeded to evaluate the actual acoustic performance, and the result indicates that the intake sound pressure level is greatly attenuated. Typically in the range of 600–1500 Hz, the insertion loss of the intake noise at the decelerating moment is almost 20 d B(A), and the overall noise is reduced more than 14.2 d B(A). In conclusion, the perforated intake pipe has been proved excellent in improving the acoustic performance of intake system and could provide the guidance for the automotive engineering application.展开更多
Mortality is normal and natural in aquaculture experiments. However, it becomes a problem when measuring feed intake as a component of nutrient utilization parameters such as： feed conversion ratio, feed conversion e...Mortality is normal and natural in aquaculture experiments. However, it becomes a problem when measuring feed intake as a component of nutrient utilization parameters such as： feed conversion ratio, feed conversion efficiency, apparent net protein utilization, protein efficiency ratio and protein productive value. In order to accurately evaluate feed intake with due consideration of mortality encountered, a formulae was developed using empirical data obtained from an experiement that had mortality. The formulae Fwas： total feed consumed by numbers of survived fishes=DL∑i=1n（Fi/Ni）N. Where, D=Numbers of days fishes were fed within each period ibefore it was adjusted（e.g fortnight）, it was constant throught period of experiment; F=Uantity of feed fed per day for a fortnight before the quantity was adjusted, it changed every fortnight; L=Numbers of living fishes at the end of experimental period; N=Numbers of fishes at each weighing period, it might change every fortnight or might be constant if no mortality occurred; while n=Numbers of times fishes were weighed and quantity of feed was adjusted but this did not include the final weighing at the termination of experiment. However, if the fishes were weighed weekly, then D=6.展开更多
healthy periparturient cows were randomly allocated into three groups and fed 100% energy diet (NRC standard diets), 120% energy diet and 80% energy diet, respectively, beginning at 28 days prior to anticipated partur...healthy periparturient cows were randomly allocated into three groups and fed 100% energy diet (NRC standard diets), 120% energy diet and 80% energy diet, respectively, beginning at 28 days prior to anticipated parturition. After parturition, all the cows were provided with the lactation ration ad libitum until the day 56 postpartum. The objectives of the study were to investigate the effect of energy intake during the dry period on the production performance in the postpartum cows. The results indicated that the cows fed with high energy diet during the dry period had a lower dry material intake (DMI) and reduced milk production and a significant body weight (BW) loss compared with the cows fed with 80% energy diet and 100% energy diet. The results suggested that energy intake during the dry period was an important factor that influences and regulates DMI, milk production and energy equilibration of postparturient cows.展开更多
The status of PCDDs and PCDFs content in retail foods from a certain area by Isotope Dilution HRGC-HRMS was surveyed and the local population PCDD/Fs exposure from diverse foods and health risk was evaluated.PCDD/Fs w...The status of PCDDs and PCDFs content in retail foods from a certain area by Isotope Dilution HRGC-HRMS was surveyed and the local population PCDD/Fs exposure from diverse foods and health risk was evaluated.PCDD/Fs was extracted from samples by Soxhlet extraction,concentrated and purified by FMS column chromatograph,carbon column enrichment.Confirmation and quantitative analysis at pg/g level of PCDD/Fs was performed by HRGC/HRMS using multiple ion detection mode(MID).TEQ concentration was calculated by WHO-TEF multiplying by concentration of seventeen PCDD/Fs congener.Median of PCDD/Fs concentration for fish,livestock,poultry,egg,vegetable oil,milk,vegetable totally 100 samples for ten diverse foods didn’t exceed the limit standards by EU.The level of PCDD/Fs for different food in the certain area was lower or comparable to the data reported by developed country in the world.The total weekly intake and monthly intake for local population or national population was 3.44,14.8 WHO-TEQ/kg BW and 1.5,6.42 pg WHO-TEQ/kg BW respectively,the value was lower than the Tolerable Weekly Intake of 14 pg WHO TEQ/kg BW for PCDDs,PCDFs and dioxin-like PCBs established by EU Scientific Committee for Food.The dietary PCDD/Fs intake for local people was higher than national population.And animal food was the dominant contributor to the total dietary intake,which accounted for more than 70 percent.These levels of consumption of diverse food containing typical levels of PCDD/Fs doesn’t present a risk to the health of the local population.But integrative dietary intake could be evaluated including of PCBs intake for population in the future.展开更多
Soil cadmium(Cd)contamination resulted from mining and smelting is a major environmental concern,and health risk associated with Cd exposure to multi-media through muti-pathway is increasing.Cd concentrations in soils...Soil cadmium(Cd)contamination resulted from mining and smelting is a major environmental concern,and health risk associated with Cd exposure to multi-media through muti-pathway is increasing.Cd concentrations in soils,vegetables and paddy rice were investigated,and potential non-carcinogenic and carcinogenic health risks exposure to Cd were estimated at six villages around the Dabaoshan Mine,South China.A total of 87 soil samples were found to exceed the China's maximum permission level(MPL)for Cd,while the highest value of 4.42 mg/kg was found near irrigation ditch associated with Hengshi River in Xinyi(XY)Village.Cd contents in vegetables and rice exceeded the maximum permissible concentration by more than five times in every village.Cadmium accumulation in plants is in the order of celery>lactuca sativa L>Chinese cabbage>Romaine lettuce>asparagus lettuce>mustard>cabbage mustard>cabbage.The mean hazard quotient(HQ)of all villages is in the range of [5.29,25.75],and the mean values of cancer risk for investigated areas are more than 10 times greater than the USEPA(2009)threshold limit value of 10-4.Moreover,human non-carcinogenic and carcinogenic risks are mainly attributable to paddy rice intake,followed by vegetables intake,soil ingestion,inhalation,and dermal contact.The results indicate that Cd has a huge potential risk on human health for the local residents.展开更多
To investigate the effects ofMoringa oleifera leaf meal （MOLM） on the performance and haematology of broiler finisher using 120 Cobb chicks of 4 weeks old broiler chicks. The birds were assigned randomly into four d...To investigate the effects ofMoringa oleifera leaf meal （MOLM） on the performance and haematology of broiler finisher using 120 Cobb chicks of 4 weeks old broiler chicks. The birds were assigned randomly into four dietary treatments containing MOLM at 0, 6%, 8%, and 10% （treatments 1, 2, 3 and 4） inclusion levels, respectively, in a complete randomized design experiment. The effect of the dietary treatments on the growth performance and blood parameters of the broiler finisher was determined. MOLM at a rate of 6% （T2）, 8% （T3）, and 10% （T4） of the diets （as fed basis） to replace 3.2%, 5.6% and 8.6% of the crude protein （CP） of the control diet. The daily feed, dry matter and CP intake of the chicks fed MOLM diets were higher （p〈0.05） than those fed the control diet. Average weight gain （AWG） of birds fed MOLM diets reduced as inclusion levels increases 09〈0.05） than those fed the control diet. Chicks fed T2 showed higher （p〈0.05） AWG than those on T3 and T4. Feed conversion ratios （FCR, weight gain/g and feed intake） were higher for chicks fed MOLM. MOLM showed minimal deleterious effects in birds. However, birds fed T2 （6%） diets recorded significantly （p〈0.05） the highest body weight gain. There were significant differences （p〈0.05） among groups in packed cell volume （PVC） of birds. The haemoglobin （Hb）, mean corpuscular volume （MCV）, mean corpuscular haemoglobin （MCH） and mean corpuscular haemoglobin concentration （MCHC） counts showed no significant difference （p〉0.05） among treatments. The results indicated that at 10% in the diets of broiler finisher chick, MOLM could be substituted with expensive conventional protein sources without any deleterious effects on performance and blood parameters of broiler finisher chicken.展开更多
In 1995 Ince[1] wrote an article for the Times Higher Educational Supplement noting that there was little theoretical understanding of software engineering and that therefore computer studies did not constitute an aca...In 1995 Ince[1] wrote an article for the Times Higher Educational Supplement noting that there was little theoretical understanding of software engineering and that therefore computer studies did not constitute an academic discipline.Computing departments should be balkanised.Computing staff should be dispersed to other departments such as maths,psychology and business studies.This contro.ersy has recently been rein.igorated by McBride’s article[2] in the same paper and on the British Computer Society web site[3] arguing that in face of the massi.e decline in computing student intake onto uni.ersity undergraduate courses that the future for traditional courses is bleak.The reaction generated[3-4] reflects the anxiety within computing departments.The concern is e.ident.展开更多
基金Project(51176014)supported by the National Natural Science Foundation of ChinaProject(2016JJ2003)supported by Natural Scienceof Hunan Province,ChinaProject(KF1605)supported by Key Laboratory of Safety Design and Reliability Technology of Engineering Vehicle in Hunan Province,China。
文摘To ensure the control of the precision of air-fuel ratio(AFR)of port fuel injection(PFI)spark ignition(SI)engines,a chaos radial basis function(RBF)neural network is used to predict the air intake flow of the engine.The data of air intake flow is proved to be multidimensionally nonlinear and chaotic.The RBF neural network is used to train the reconstructed phase space of the data.The chaos algorithm is employed to optimize the weights of output layer connection and the radial basis center of Gaussian function in hidden layer.The simulation results obtained from Matlab/Simulink illustrate that the model has higher accuracy compared to the conventional RBF model.The mean absolute error and the mean relative error of the chaos RBF model can reach 0.0017 and 0.48,respectively.
基金Project(51705454)supported by the National Natural Science Foundation of China
文摘Exact simulation of the acoustic performance is essential to the engineering application for a vehicle intake system. The rectangular-pulse method based on the computational fluid dynamics approach was employed for calculating the transmission loss. Firstly, the transmission loss of the single-cavity element was simulated without any airflow, and the effects of different structural parameters on the acoustic performance were investigated comprehensively. Secondly, the static transmission loss of the perforated intake pipe was obtained by the rectangular-pulse method, which is proved to be accurate enough compared with the result by finite element method. Thirdly, under the different conditions of the mean airflow and the operating temperature, the specific transmission loss was acquired respectively. In general, the peaks of the transmission loss are shifted to the lower frequency range because of the reverse airflow, but the amplitudes are irregularly changed. Besides, when the operating temperature increases, the peaks are shifted to the higher frequencies. Finally, with the designed perforated pipe installed to the intake system, the road tests were proceeded to evaluate the actual acoustic performance, and the result indicates that the intake sound pressure level is greatly attenuated. Typically in the range of 600–1500 Hz, the insertion loss of the intake noise at the decelerating moment is almost 20 d B(A), and the overall noise is reduced more than 14.2 d B(A). In conclusion, the perforated intake pipe has been proved excellent in improving the acoustic performance of intake system and could provide the guidance for the automotive engineering application.
文摘Mortality is normal and natural in aquaculture experiments. However, it becomes a problem when measuring feed intake as a component of nutrient utilization parameters such as： feed conversion ratio, feed conversion efficiency, apparent net protein utilization, protein efficiency ratio and protein productive value. In order to accurately evaluate feed intake with due consideration of mortality encountered, a formulae was developed using empirical data obtained from an experiement that had mortality. The formulae Fwas： total feed consumed by numbers of survived fishes=DL∑i=1n（Fi/Ni）N. Where, D=Numbers of days fishes were fed within each period ibefore it was adjusted（e.g fortnight）, it was constant throught period of experiment; F=Uantity of feed fed per day for a fortnight before the quantity was adjusted, it changed every fortnight; L=Numbers of living fishes at the end of experimental period; N=Numbers of fishes at each weighing period, it might change every fortnight or might be constant if no mortality occurred; while n=Numbers of times fishes were weighed and quantity of feed was adjusted but this did not include the final weighing at the termination of experiment. However, if the fishes were weighed weekly, then D=6.
文摘healthy periparturient cows were randomly allocated into three groups and fed 100% energy diet (NRC standard diets), 120% energy diet and 80% energy diet, respectively, beginning at 28 days prior to anticipated parturition. After parturition, all the cows were provided with the lactation ration ad libitum until the day 56 postpartum. The objectives of the study were to investigate the effect of energy intake during the dry period on the production performance in the postpartum cows. The results indicated that the cows fed with high energy diet during the dry period had a lower dry material intake (DMI) and reduced milk production and a significant body weight (BW) loss compared with the cows fed with 80% energy diet and 100% energy diet. The results suggested that energy intake during the dry period was an important factor that influences and regulates DMI, milk production and energy equilibration of postparturient cows.
文摘The status of PCDDs and PCDFs content in retail foods from a certain area by Isotope Dilution HRGC-HRMS was surveyed and the local population PCDD/Fs exposure from diverse foods and health risk was evaluated.PCDD/Fs was extracted from samples by Soxhlet extraction,concentrated and purified by FMS column chromatograph,carbon column enrichment.Confirmation and quantitative analysis at pg/g level of PCDD/Fs was performed by HRGC/HRMS using multiple ion detection mode(MID).TEQ concentration was calculated by WHO-TEF multiplying by concentration of seventeen PCDD/Fs congener.Median of PCDD/Fs concentration for fish,livestock,poultry,egg,vegetable oil,milk,vegetable totally 100 samples for ten diverse foods didn’t exceed the limit standards by EU.The level of PCDD/Fs for different food in the certain area was lower or comparable to the data reported by developed country in the world.The total weekly intake and monthly intake for local population or national population was 3.44,14.8 WHO-TEQ/kg BW and 1.5,6.42 pg WHO-TEQ/kg BW respectively,the value was lower than the Tolerable Weekly Intake of 14 pg WHO TEQ/kg BW for PCDDs,PCDFs and dioxin-like PCBs established by EU Scientific Committee for Food.The dietary PCDD/Fs intake for local people was higher than national population.And animal food was the dominant contributor to the total dietary intake,which accounted for more than 70 percent.These levels of consumption of diverse food containing typical levels of PCDD/Fs doesn’t present a risk to the health of the local population.But integrative dietary intake could be evaluated including of PCBs intake for population in the future.
基金Project(51204074)supported by the National Natural Science Foundation of ChinaProjects(2010009017,201209048,ZX021-201106-031)supported by the National Environmental Protection Public Welfare Industry Targeted Research Fund,China
文摘Soil cadmium(Cd)contamination resulted from mining and smelting is a major environmental concern,and health risk associated with Cd exposure to multi-media through muti-pathway is increasing.Cd concentrations in soils,vegetables and paddy rice were investigated,and potential non-carcinogenic and carcinogenic health risks exposure to Cd were estimated at six villages around the Dabaoshan Mine,South China.A total of 87 soil samples were found to exceed the China's maximum permission level(MPL)for Cd,while the highest value of 4.42 mg/kg was found near irrigation ditch associated with Hengshi River in Xinyi(XY)Village.Cd contents in vegetables and rice exceeded the maximum permissible concentration by more than five times in every village.Cadmium accumulation in plants is in the order of celery>lactuca sativa L>Chinese cabbage>Romaine lettuce>asparagus lettuce>mustard>cabbage mustard>cabbage.The mean hazard quotient(HQ)of all villages is in the range of [5.29,25.75],and the mean values of cancer risk for investigated areas are more than 10 times greater than the USEPA(2009)threshold limit value of 10-4.Moreover,human non-carcinogenic and carcinogenic risks are mainly attributable to paddy rice intake,followed by vegetables intake,soil ingestion,inhalation,and dermal contact.The results indicate that Cd has a huge potential risk on human health for the local residents.
文摘To investigate the effects ofMoringa oleifera leaf meal （MOLM） on the performance and haematology of broiler finisher using 120 Cobb chicks of 4 weeks old broiler chicks. The birds were assigned randomly into four dietary treatments containing MOLM at 0, 6%, 8%, and 10% （treatments 1, 2, 3 and 4） inclusion levels, respectively, in a complete randomized design experiment. The effect of the dietary treatments on the growth performance and blood parameters of the broiler finisher was determined. MOLM at a rate of 6% （T2）, 8% （T3）, and 10% （T4） of the diets （as fed basis） to replace 3.2%, 5.6% and 8.6% of the crude protein （CP） of the control diet. The daily feed, dry matter and CP intake of the chicks fed MOLM diets were higher （p〈0.05） than those fed the control diet. Average weight gain （AWG） of birds fed MOLM diets reduced as inclusion levels increases 09〈0.05） than those fed the control diet. Chicks fed T2 showed higher （p〈0.05） AWG than those on T3 and T4. Feed conversion ratios （FCR, weight gain/g and feed intake） were higher for chicks fed MOLM. MOLM showed minimal deleterious effects in birds. However, birds fed T2 （6%） diets recorded significantly （p〈0.05） the highest body weight gain. There were significant differences （p〈0.05） among groups in packed cell volume （PVC） of birds. The haemoglobin （Hb）, mean corpuscular volume （MCV）, mean corpuscular haemoglobin （MCH） and mean corpuscular haemoglobin concentration （MCHC） counts showed no significant difference （p〉0.05） among treatments. The results indicated that at 10% in the diets of broiler finisher chick, MOLM could be substituted with expensive conventional protein sources without any deleterious effects on performance and blood parameters of broiler finisher chicken.
文摘In 1995 Ince[1] wrote an article for the Times Higher Educational Supplement noting that there was little theoretical understanding of software engineering and that therefore computer studies did not constitute an academic discipline.Computing departments should be balkanised.Computing staff should be dispersed to other departments such as maths,psychology and business studies.This contro.ersy has recently been rein.igorated by McBride’s article[2] in the same paper and on the British Computer Society web site[3] arguing that in face of the massi.e decline in computing student intake onto uni.ersity undergraduate courses that the future for traditional courses is bleak.The reaction generated[3-4] reflects the anxiety within computing departments.The concern is e.ident.
