Feedstuff intake plays key role in impacting the yield and quality of milk. In this study, we discussed the contents of trace metal elements in cow milk impacted by different feedstuffs. We detected the contents of Pb...Feedstuff intake plays key role in impacting the yield and quality of milk. In this study, we discussed the contents of trace metal elements in cow milk impacted by different feedstuffs. We detected the contents of Pb, Cd, As, Cu, Mg, Ca, Fe and Zn in different feedstuffs and milk by atomic absorption spectrophotometry. The determinations of Pb, Cd and As contents were by graphite furnace A_AS and Cu, Mg, Ca, Fe and Zn was by flame atomic absorption spectrometry. The results showed that Pb, Cd, As and Cu presented in feedstuffs, but Pb, Cd and As were lowly detected in milk samples, and Cu was not detected in milk samples. The content of Mg in concentrates was lower than that in forages. However, the content of Mg in milk from concentrate feed was higher than that in forage feed. This suggested that the utilization of Mg in concentrate feed was higher than that in forage feed. The contents of Ca and Zn were opposite to Mg, and the utilization of Ca and Zn in forage feed was higher than that in concentrate feed. There was no obviously change law of Fe in different feedstuffs and milk samples. The relationship between the contents of trace metal elements in milk to feedstuffs would provide a theoretical basis for dairy farming. It would be useful for improving the milk yield and milk quality of dairy production.展开更多
This paper, probing into heavy metal control in domestic rubbish by source screening and nutrient element analysis, revealed the feasibility of source control of heavy metals and the suitability of rubbish as turfgras...This paper, probing into heavy metal control in domestic rubbish by source screening and nutrient element analysis, revealed the feasibility of source control of heavy metals and the suitability of rubbish as turfgrass medium. Heavy metals in domestic rubbish were controlled by source screening before composting. The study consisted of a control with garden soil. The contents of main mineral elements and heavy metals in rubbish compost and control were determined by the method of ICP-AES. The results showed that heavy metal concentrations in rubbish were lower than those in garden soil, and little difference occurred between rubbish and garden soil in main mineral element concentrations. Based on this, it was concluded that rubbish compost was favorable for using as turfgrass medium and heavy metal control in rubbish by source screening was effective.展开更多
Concentration of heavy metals in blood and urine of rabbit after inhaling three different kinds of cigarette was studied through the animal passive smoking pattern. The samples were prepared by nitric acid solution di...Concentration of heavy metals in blood and urine of rabbit after inhaling three different kinds of cigarette was studied through the animal passive smoking pattern. The samples were prepared by nitric acid solution digestion and determination of seven kinds of heavy metals including Hg, Se, Sn, Pb, Cd, Ni and Cr was performed by inductively coupled plasma-atomic emission spectrometry （ICP-AES）. The ICP-AES method was established with good precision and accuracy, relative standard deviation （n=6） was between 2.9% and 5.9%, and the recovery was in the range of 95.0%-104.2%. Concentration of six heavy metals increases in some extent in blood and urine after period of smoking and the increasing of heavy metals in blood and urine all shows time dependence. Significantly higher heavy metal levels are observed in the blood and urine of the cigarette inhaling rabbits in the exposed group. The concentration of six kinds of heavy metals in the blood of the rabbit increases after 16 weeks exposing to cigarette smoking. Three times of rig, ten times of Se and trace amount ofPb, Cd, Ni and Cr are detected in the blood after 16 weeks of smoking. For urine samples, about three times of Hg, two times of Se, five times of Pb and trace amount of Cd are detected after 16 weeks of inhalation of cigarette. Comparatively, higher concentration of heavy metals are detected after inhaling of Nise cigarette.展开更多
采用T2Cu和CuSi3焊丝在相同工艺参数下对厚度为1 mm的TC4钛合金及304不锈钢进行焊接,并借助光学显微镜(optical microscopy,OM)和扫描电镜(scanning electron microscopy,SEM)研究了两种焊丝下的TC4/304异种金属焊接熔池冶金行为.对比...采用T2Cu和CuSi3焊丝在相同工艺参数下对厚度为1 mm的TC4钛合金及304不锈钢进行焊接,并借助光学显微镜(optical microscopy,OM)和扫描电镜(scanning electron microscopy,SEM)研究了两种焊丝下的TC4/304异种金属焊接熔池冶金行为.对比分析了不同焊丝成分,尤其是Si元素的加入对TC4/304异种金属接头宏观成形、界面微观组织和力学性能的影响.结果表明,Si元素的加入使液态熔池流动性显著增强,消除了凹陷和孔洞等缺陷,解决了焊缝背部熔合不良问题,焊缝宏观成形显著改善.两种焊丝均有效阻隔了Ti,Fe原子,钛/铜界面未生成Ti-Fe化合物,但在焊缝中心以及铜/钢界面处生成了少量Ti-Fe相.CuSi3焊丝中充足的Si元素不仅使Ti5Si3相形核生长的更加充分,在熔池流动的作用下均匀分布于焊缝中,对接头起到弥散强化作用.与T2Cu焊丝相比,CuSi3焊丝所得接头的抗拉强度提升了81.4%,最高达到366.8 MPa.展开更多
文摘Feedstuff intake plays key role in impacting the yield and quality of milk. In this study, we discussed the contents of trace metal elements in cow milk impacted by different feedstuffs. We detected the contents of Pb, Cd, As, Cu, Mg, Ca, Fe and Zn in different feedstuffs and milk by atomic absorption spectrophotometry. The determinations of Pb, Cd and As contents were by graphite furnace A_AS and Cu, Mg, Ca, Fe and Zn was by flame atomic absorption spectrometry. The results showed that Pb, Cd, As and Cu presented in feedstuffs, but Pb, Cd and As were lowly detected in milk samples, and Cu was not detected in milk samples. The content of Mg in concentrates was lower than that in forages. However, the content of Mg in milk from concentrate feed was higher than that in forage feed. This suggested that the utilization of Mg in concentrate feed was higher than that in forage feed. The contents of Ca and Zn were opposite to Mg, and the utilization of Ca and Zn in forage feed was higher than that in concentrate feed. There was no obviously change law of Fe in different feedstuffs and milk samples. The relationship between the contents of trace metal elements in milk to feedstuffs would provide a theoretical basis for dairy farming. It would be useful for improving the milk yield and milk quality of dairy production.
基金NationalNaturalScienceFoundation (59878033)Tianjin Science and Technology Developm entProgram (043100611).
文摘This paper, probing into heavy metal control in domestic rubbish by source screening and nutrient element analysis, revealed the feasibility of source control of heavy metals and the suitability of rubbish as turfgrass medium. Heavy metals in domestic rubbish were controlled by source screening before composting. The study consisted of a control with garden soil. The contents of main mineral elements and heavy metals in rubbish compost and control were determined by the method of ICP-AES. The results showed that heavy metal concentrations in rubbish were lower than those in garden soil, and little difference occurred between rubbish and garden soil in main mineral element concentrations. Based on this, it was concluded that rubbish compost was favorable for using as turfgrass medium and heavy metal control in rubbish by source screening was effective.
基金Project(11JJ5053) supported by the Provincial Natural Science Foundation of Hunan Province,China
文摘Concentration of heavy metals in blood and urine of rabbit after inhaling three different kinds of cigarette was studied through the animal passive smoking pattern. The samples were prepared by nitric acid solution digestion and determination of seven kinds of heavy metals including Hg, Se, Sn, Pb, Cd, Ni and Cr was performed by inductively coupled plasma-atomic emission spectrometry （ICP-AES）. The ICP-AES method was established with good precision and accuracy, relative standard deviation （n=6） was between 2.9% and 5.9%, and the recovery was in the range of 95.0%-104.2%. Concentration of six heavy metals increases in some extent in blood and urine after period of smoking and the increasing of heavy metals in blood and urine all shows time dependence. Significantly higher heavy metal levels are observed in the blood and urine of the cigarette inhaling rabbits in the exposed group. The concentration of six kinds of heavy metals in the blood of the rabbit increases after 16 weeks exposing to cigarette smoking. Three times of rig, ten times of Se and trace amount ofPb, Cd, Ni and Cr are detected in the blood after 16 weeks of smoking. For urine samples, about three times of Hg, two times of Se, five times of Pb and trace amount of Cd are detected after 16 weeks of inhalation of cigarette. Comparatively, higher concentration of heavy metals are detected after inhaling of Nise cigarette.
