High-frequency pulsed(HFP)gas tungsten arc welding(GTAW)has shown excellent performance in welding of aluminum alloys in recent years,which makes itself a promisingly potential technique for part manufacturing in avia...High-frequency pulsed(HFP)gas tungsten arc welding(GTAW)has shown excellent performance in welding of aluminum alloys in recent years,which makes itself a promisingly potential technique for part manufacturing in aviation industry.However,existing researches generally focuses on the effect of a single parameter while lacks multivariable researches.Considering of the fact that gap and misalignment are inevitable in real part clamping,adaptive intelligent welding is usually used during automatic manufacturing,which means under the control of filler wire amount per length of a weld,other parameters including current,welding speed and wire feed speed during one single weld are changing according to the specific clamping situation.Therefore,the influence of specific energy input led by different welding parameters within one adaptive welding program on microstructure and mechanical property of the weld needs to be clarified.This study investigates the effect of welding heat input(ranging from 1048.3 J/mm to 825.6 J/mm within one adaptive welding program control)on the formation quality of 3.25 mm thick 6061 aluminum alloy joints fabricated by HFP-GTAW with 4043 filler wire.According to the obtained results,non-monotonic relationship between heat input and porosity,with an optimal minimum of 4.92%achieved at an intermediate heat input of 856.8 J/mm.The 21.2%decrease of energy input during welding process would reduce the average grain size in the weld center and adjacent to fusion line by 18.6%and 19.4%,respectively.The ratios between fluctuation range to minimum value in average yield and the relative ranges of yield strength and ultimate tensile strength across the tested heat inputs were 14.7%and 12.7%,respectively.The findings provide a general overview on how the microstructure and mechanical properties would fluctuate in an adaptively controlled HFP-GTAW fabricated aluminum alloy weld.展开更多
This study evaluated the effects of rapeseed meal(RM)and condensed tannin(CT)on the growth and nutritional metabolism of largemouth bass(Micropterus salmoides),and speculated whether there was interaction between anti...This study evaluated the effects of rapeseed meal(RM)and condensed tannin(CT)on the growth and nutritional metabolism of largemouth bass(Micropterus salmoides),and speculated whether there was interaction between anti-nutritional factors in RM.Eight diets were formulated for 55-day feeding trial,six of which were practical diet groups,including control group(CG),five RM inclusive groups with graded RM levels of 5%(RM5),10%(RM10),15%(RM15),20%(RM20)and 25%(RM25)partially replacing fishmeal,and the other two were semi-purified diets with 0.062%CT(CT5)≈the CT content in the RM5 and 0.31%CT(CT25)≈the CT content in the RM25.The results of the experiments on replacing fishmeal with RM demonstrated that with the increase of RM substitution level,the weight gain rate(WGR),survival rate(SR)and specific growth rate(SGR)of largemouth bass showed a downward trend.High levels of RM led to the inhibition of digestive enzyme activity in largemouth bass,as well as the manifestation of abnormal markers related to protein,fat,and carbohydrate metabolism in both plasma and liver.RM reduced muscle protein and fat content,although the effect was not statistically significant at 5%RM level.The results of CT concentration experiments showed that the addition of 0.31%CT significantly reduced WGR,SGR,SR,protein efficiency ratio(PER)and gastrointestinal digestive enzyme activity,and significantly increased the feed coefficient ratio(FCR),plasma ammonia(PA),plasma glucose(PG),and hepatic glycogen(HG)and liver triglyceride(TG).The addition of 0.062%CT significantly reduced PG and HG.Supplementation of CT significantly reduced muscle fat.Among the groups of CT supplementation and RM,CT5 exhibited superior WGR,PER and FCR compared to RM5,along with enhanced intestinal trypsin,amylase activity,liver glutamic pyruvic transaminase(GPT)activity and decreased content of HG and liver TG;CT25 exhibited decreased activities of gastric lipase(LPS),enteric trypsin and pepsin,and increased content of total cholesterol(T-CHO)and glucose in plasma in compariosn to RM25,accompanied with no significant change in growth performance.Therefore,largemouth bass exhibited tolerance to a 5%inclusion of RM in the feed without compromising their growth,digestion and metabolic functions.The incorporation of 5%RM,equivalent to a supplemental 0.062%CT,had regulatory effects on the digestion and metabolism of largemouth bass while improving feed utilization.There was an interaction among anti-nutritional factors in RM,with synergistic effect being evident at low RM levels,whereas antagonism more promient at high levels of RM.展开更多
An 8-week feeding trial investigated the optimum dietary vitamin K3 requirements of largemouth bass.A total of 600 healthy fish(12.96±0.07 g)were fed diets containing varying levels of vitamin K3 at 0.78(K0),5.80...An 8-week feeding trial investigated the optimum dietary vitamin K3 requirements of largemouth bass.A total of 600 healthy fish(12.96±0.07 g)were fed diets containing varying levels of vitamin K3 at 0.78(K0),5.80(K5),10.82(K10),15.84(K15),and 20.85(K20)mg/kg with four replicates per level.Results showed that dietary vitamin K3 enhanced growth,with weight gain rate and specific growth rate in K15 trials significantly higher than K0 trials(P<0.05).No significant difference was observed in the content of crude protein,crude lipid,moisture,ash,and phosphorus in muscle tissue(P>0.05).However,the supplementation of vitamin K3 significantly contributed to calcium accumulation in muscle tissues and vertebrae(P<0.05)and increased red blood cell counts(P<0.05).The blood coagulation time decreased significantly with increasing dietary vitamin K3 from 0.78 to 10.82 mg/kg(P<0.05)before stabilizing(P>0.05).The antioxidant capacity was improved with the addition of vitamin K3,which was inconsistent with the changes in malondialdehyde and MK-4(a form of menaquinone)within liver and serum,suggesting that the toxicity of excessive artificial vitamin K3 may account for this difference.Using regression analysis,the appropriate dietary vitamin K3 levels within a largemouth bass diet was determined to be in the range of 9.93-15.22 mg/kg,which will provide a reference for the preparation of vitamin premix and artificial diet for largemouth bass.展开更多
This study was carried out to determine the effects of abrupt salinity change on osmoregulatory ability of the spottedtail goby Synechogobius ommaturus.720 juvenile fish(65.3±11.8 g)were transferred to 200 L tank...This study was carried out to determine the effects of abrupt salinity change on osmoregulatory ability of the spottedtail goby Synechogobius ommaturus.720 juvenile fish(65.3±11.8 g)were transferred to 200 L tanks(with 40 juveniles in each tank),in which salinities were abruptly changed from 10 to 20,30,40,50 and freshwater.Survival rate,serum osmolality,electrolytes(Na^(+),Cl^(-),and K^(+))and gill Na^(+)/K^(+)-ATPase(NKA)activity were assessed successively in 528 h.Results showed serum osmolality,ion concentrations and gill Na^(+)/K^(+)-ATPase activity increased significantly when fish were transferred to salinity 40 and 50 and all fish in these groups died by the end of the experiment.Serum osmolality,Na^(+),Cl^(-)and K^(+)in fish transferred to a salinity of 20,30 and freshwater were not affected and no mortality was detected.Compared with the control group,a significantly decrease of NKA activity happened in the freshwater group,but the activity in 20 and 30 groups was not affected significantly.The results indicated that S.ommaturus could adapt rapidly and maintain homeostasis in a wide range of salinities(from freshwater to salinity 30)and this species may be suitable for aquaculture in estuarine and coastal areas where rapid salinity fluctuations commonly occur.展开更多
In order to study the metabolomic responses of rapeseed meal on grass carp and the role that tannin plays in those responses,grass carp were fed four diets for an eight week trial.Two were practical diets:FM diet cont...In order to study the metabolomic responses of rapeseed meal on grass carp and the role that tannin plays in those responses,grass carp were fed four diets for an eight week trial.Two were practical diets:FM diet contained 10%fishmeal without rapeseed meal,RM diet contained 50%rapeseed meal without fishmeal;the other two were semi-purified diets without(T0)or with 1.25%(T1)of supplemental hydrolysable tannin.The tannin content in the RM diet was close to that of T1.The rate of weight gain for RM was significantly lower than FM,while the feed conversion ratio in the T1 was significantly higher than T0.The muscle lipid and protein content was significantly lower and glycogen higher in the RM and T1 compared to the other treatments.The percent of muscle-saturated fatty acid(SFA)in the RM and T1 groups was significantly lower than FM and T0 groups,respectively,while the mono-unsaturated fatty acid(MUFA)in the RM group was significantly higher than FM.The hepatic activities of alanine aminotransferase and aspartate aminotransferase were lower and the hepatic glycogen and malonaldehyde were higher in the T1 and RM than the other treatments.The total serum protein,globulin,and triglycerides were significantly higher in T1 and RM;the alanine aminotransferase in the T1 was significantly higher than T0;and the aspartate aminotransferase in the RM and T0 groups were significantly higher than the other treatments.In a metabolomic assay,29 differential metabolites were identified between T0 and T1,23 metabolites were downregulated,and 6 metabolites were upregulated in T1 compared to T0.Ninety-two differential metabolites were identified between FM and RM,31 metabolites were downregulated,and 61 metabolites were upregulated in RM compared to FM.These indicated that lipid utilization and carbohydrate metabolism might be improved,while the protein metabolism was suppressed by rapeseed meal.The abnormal protein and lipid metabolism may be partly caused by tannin in the rapeseed meal,as the tannin contained within the rapeseed meal seemed to bring different effects that the tannin additive.展开更多
基金supported by the Commercial Aircraft Corporation of China Ltd.(Grant No.COMAC-SFGS-2024–569)Fundamental Research Funds for the Central Universities and Institute of Marine Equipment,Shanghai Rising-Star Program of Science and Technology Commission of Shanghai Municipality(Grant No.23QA1404700)+1 种基金National Natural Science Foundation of China(Grant No.52475384,52505409)China Postdoctoral Science Foundation(Grant No.2024M761963)。
文摘High-frequency pulsed(HFP)gas tungsten arc welding(GTAW)has shown excellent performance in welding of aluminum alloys in recent years,which makes itself a promisingly potential technique for part manufacturing in aviation industry.However,existing researches generally focuses on the effect of a single parameter while lacks multivariable researches.Considering of the fact that gap and misalignment are inevitable in real part clamping,adaptive intelligent welding is usually used during automatic manufacturing,which means under the control of filler wire amount per length of a weld,other parameters including current,welding speed and wire feed speed during one single weld are changing according to the specific clamping situation.Therefore,the influence of specific energy input led by different welding parameters within one adaptive welding program on microstructure and mechanical property of the weld needs to be clarified.This study investigates the effect of welding heat input(ranging from 1048.3 J/mm to 825.6 J/mm within one adaptive welding program control)on the formation quality of 3.25 mm thick 6061 aluminum alloy joints fabricated by HFP-GTAW with 4043 filler wire.According to the obtained results,non-monotonic relationship between heat input and porosity,with an optimal minimum of 4.92%achieved at an intermediate heat input of 856.8 J/mm.The 21.2%decrease of energy input during welding process would reduce the average grain size in the weld center and adjacent to fusion line by 18.6%and 19.4%,respectively.The ratios between fluctuation range to minimum value in average yield and the relative ranges of yield strength and ultimate tensile strength across the tested heat inputs were 14.7%and 12.7%,respectively.The findings provide a general overview on how the microstructure and mechanical properties would fluctuate in an adaptively controlled HFP-GTAW fabricated aluminum alloy weld.
基金supported by the National Key Research and Development Program of China (2022YFD2400803).
文摘This study evaluated the effects of rapeseed meal(RM)and condensed tannin(CT)on the growth and nutritional metabolism of largemouth bass(Micropterus salmoides),and speculated whether there was interaction between anti-nutritional factors in RM.Eight diets were formulated for 55-day feeding trial,six of which were practical diet groups,including control group(CG),five RM inclusive groups with graded RM levels of 5%(RM5),10%(RM10),15%(RM15),20%(RM20)and 25%(RM25)partially replacing fishmeal,and the other two were semi-purified diets with 0.062%CT(CT5)≈the CT content in the RM5 and 0.31%CT(CT25)≈the CT content in the RM25.The results of the experiments on replacing fishmeal with RM demonstrated that with the increase of RM substitution level,the weight gain rate(WGR),survival rate(SR)and specific growth rate(SGR)of largemouth bass showed a downward trend.High levels of RM led to the inhibition of digestive enzyme activity in largemouth bass,as well as the manifestation of abnormal markers related to protein,fat,and carbohydrate metabolism in both plasma and liver.RM reduced muscle protein and fat content,although the effect was not statistically significant at 5%RM level.The results of CT concentration experiments showed that the addition of 0.31%CT significantly reduced WGR,SGR,SR,protein efficiency ratio(PER)and gastrointestinal digestive enzyme activity,and significantly increased the feed coefficient ratio(FCR),plasma ammonia(PA),plasma glucose(PG),and hepatic glycogen(HG)and liver triglyceride(TG).The addition of 0.062%CT significantly reduced PG and HG.Supplementation of CT significantly reduced muscle fat.Among the groups of CT supplementation and RM,CT5 exhibited superior WGR,PER and FCR compared to RM5,along with enhanced intestinal trypsin,amylase activity,liver glutamic pyruvic transaminase(GPT)activity and decreased content of HG and liver TG;CT25 exhibited decreased activities of gastric lipase(LPS),enteric trypsin and pepsin,and increased content of total cholesterol(T-CHO)and glucose in plasma in compariosn to RM25,accompanied with no significant change in growth performance.Therefore,largemouth bass exhibited tolerance to a 5%inclusion of RM in the feed without compromising their growth,digestion and metabolic functions.The incorporation of 5%RM,equivalent to a supplemental 0.062%CT,had regulatory effects on the digestion and metabolism of largemouth bass while improving feed utilization.There was an interaction among anti-nutritional factors in RM,with synergistic effect being evident at low RM levels,whereas antagonism more promient at high levels of RM.
基金study was supported by Guangdong province key field R&D program project(No.2020B0202010001)Shanghai collaborative innovation for aquatic animal genetics and breeding.
文摘An 8-week feeding trial investigated the optimum dietary vitamin K3 requirements of largemouth bass.A total of 600 healthy fish(12.96±0.07 g)were fed diets containing varying levels of vitamin K3 at 0.78(K0),5.80(K5),10.82(K10),15.84(K15),and 20.85(K20)mg/kg with four replicates per level.Results showed that dietary vitamin K3 enhanced growth,with weight gain rate and specific growth rate in K15 trials significantly higher than K0 trials(P<0.05).No significant difference was observed in the content of crude protein,crude lipid,moisture,ash,and phosphorus in muscle tissue(P>0.05).However,the supplementation of vitamin K3 significantly contributed to calcium accumulation in muscle tissues and vertebrae(P<0.05)and increased red blood cell counts(P<0.05).The blood coagulation time decreased significantly with increasing dietary vitamin K3 from 0.78 to 10.82 mg/kg(P<0.05)before stabilizing(P>0.05).The antioxidant capacity was improved with the addition of vitamin K3,which was inconsistent with the changes in malondialdehyde and MK-4(a form of menaquinone)within liver and serum,suggesting that the toxicity of excessive artificial vitamin K3 may account for this difference.Using regression analysis,the appropriate dietary vitamin K3 levels within a largemouth bass diet was determined to be in the range of 9.93-15.22 mg/kg,which will provide a reference for the preparation of vitamin premix and artificial diet for largemouth bass.
基金Financial support was provided by Agriculture Commission of Shanghai(2011/1-4)Shanghai breed industry development project(2015/17).
文摘This study was carried out to determine the effects of abrupt salinity change on osmoregulatory ability of the spottedtail goby Synechogobius ommaturus.720 juvenile fish(65.3±11.8 g)were transferred to 200 L tanks(with 40 juveniles in each tank),in which salinities were abruptly changed from 10 to 20,30,40,50 and freshwater.Survival rate,serum osmolality,electrolytes(Na^(+),Cl^(-),and K^(+))and gill Na^(+)/K^(+)-ATPase(NKA)activity were assessed successively in 528 h.Results showed serum osmolality,ion concentrations and gill Na^(+)/K^(+)-ATPase activity increased significantly when fish were transferred to salinity 40 and 50 and all fish in these groups died by the end of the experiment.Serum osmolality,Na^(+),Cl^(-)and K^(+)in fish transferred to a salinity of 20,30 and freshwater were not affected and no mortality was detected.Compared with the control group,a significantly decrease of NKA activity happened in the freshwater group,but the activity in 20 and 30 groups was not affected significantly.The results indicated that S.ommaturus could adapt rapidly and maintain homeostasis in a wide range of salinities(from freshwater to salinity 30)and this species may be suitable for aquaculture in estuarine and coastal areas where rapid salinity fluctuations commonly occur.
基金the Key Laboratory of Freshwater Aquatic Genetic Resources,the Ministry of Agriculture,the Shanghai Ocean University,Shanghai,China.
文摘In order to study the metabolomic responses of rapeseed meal on grass carp and the role that tannin plays in those responses,grass carp were fed four diets for an eight week trial.Two were practical diets:FM diet contained 10%fishmeal without rapeseed meal,RM diet contained 50%rapeseed meal without fishmeal;the other two were semi-purified diets without(T0)or with 1.25%(T1)of supplemental hydrolysable tannin.The tannin content in the RM diet was close to that of T1.The rate of weight gain for RM was significantly lower than FM,while the feed conversion ratio in the T1 was significantly higher than T0.The muscle lipid and protein content was significantly lower and glycogen higher in the RM and T1 compared to the other treatments.The percent of muscle-saturated fatty acid(SFA)in the RM and T1 groups was significantly lower than FM and T0 groups,respectively,while the mono-unsaturated fatty acid(MUFA)in the RM group was significantly higher than FM.The hepatic activities of alanine aminotransferase and aspartate aminotransferase were lower and the hepatic glycogen and malonaldehyde were higher in the T1 and RM than the other treatments.The total serum protein,globulin,and triglycerides were significantly higher in T1 and RM;the alanine aminotransferase in the T1 was significantly higher than T0;and the aspartate aminotransferase in the RM and T0 groups were significantly higher than the other treatments.In a metabolomic assay,29 differential metabolites were identified between T0 and T1,23 metabolites were downregulated,and 6 metabolites were upregulated in T1 compared to T0.Ninety-two differential metabolites were identified between FM and RM,31 metabolites were downregulated,and 61 metabolites were upregulated in RM compared to FM.These indicated that lipid utilization and carbohydrate metabolism might be improved,while the protein metabolism was suppressed by rapeseed meal.The abnormal protein and lipid metabolism may be partly caused by tannin in the rapeseed meal,as the tannin contained within the rapeseed meal seemed to bring different effects that the tannin additive.
