检索结果-南通市图书馆

Dietary copper requirement of broilers fed a corn-soybean meal diet during 22—42 d of age

在线全文

学校读者我要写书评

暂无评论

Animal Nutrition 2024年第1期16卷 96-104页

作者： Ling Zhu Wei Wu Bingxin Wu Yun Hu Liyang Zhang Weiyun Zhang Tingting Li Xiaoyan Cui Feiyu Gao Ding Li Xugang Luo Shengchen Wang Poultry Mineral Nutrition Laboratory College of Animal Science and TechnologyYangzhou University Mineral Nutrition Research Division State Key Laboratory of Animal NutritionInstitute of Animal ScienceChinese Academy of Agricultural Sciences

This research was to assess the dietary copper(Cu) requirement of broiler chickens fed a practical cornsoybean meal diet during 22—42 d of age. A total of 288 numbered Arbor Acres male broilers at 22 d of age were randomly allotted 6 treatments with 8 replicate cages(6 broilers per cage) per treatment.Broilers were fed a Cu-unsupplemented corn-soybean meal basal diet(control, containing 7.36 mg Cu/kg) or the basal diet added with 3, 6, 9, 12, or 15 mg Cu/kg from CuSO4·5H2O for 21 d. Quadratic,asymptotic and broken-line models were fitted and the best fitted models were selected to determine dietary Cu requirements. The results revealed that the contents of Cu in serum and liver, m RNA expression levels of Cu-and zinc-containing superoxide dismutase(CuZnSOD) in liver and monoamine oxidase b(MAO B) in heart, as well as protein expression level of CuZnSOD in liver were affected(P < 0.05) by supplemental Cu levels, and the above indices varied linearly and quadratically(P < 0.05)with increasing Cu levels. Dietary Cu requirements assessed according to the best fitted broken-line models(P < 0.05) of the above indexes were 10.45—13.81 mg/kg. It was concluded that mRNA expression levels of CuZnSOD in liver and MAO B in heart, as well as liver CuZnSOD protein expression level were new specific sensitive biomarkers for estimating dietary Cu requirements, and the dietary Cu requirement was recommended to be 14 mg/kg to support Cu metabolic needs related to key Cucontaining enzymes in broilers fed the corn-soybean meal diet during 22—42 d of age, which was higher than the dietary Cu requirement(8 mg/kg) for broilers at the corresponding stage suggested by the Chinese Feeding Standard of Chicken.

关键词： copper copper content Gene expression of copper-containing enzyme Requirement Broiler

Bifunctionality of Cu/ZnO catalysts for alcohol-assisted low-temperature methanol synthesis from syngas:Effect of copper content

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2017年第3期26卷 373-379页

作者： Ilho Kim Gihoon Lee Heondo Jeong Jong Ho Park Ji Chul Jung Department of Chemical Engineering Myongji University Korea Institute of Energy Research

Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO;catalysts while varying the copper content（X）. Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction intermediate in this reaction, creating a different reaction pathway. The formation of crystalline phases and characteristic morphology of the co-precipitated precursors during the co-precipitation step were important factors in obtaining an efficient Cu/ZnO catalyst with a high dispersion of metallic copper,which is one of the main active sites for methanol synthesis. The acidic properties of the Cu/ZnO catalyst were also revealed as important factors, since alcohol esterification is considered the rate-limiting step in alcohol-assisted low-temperature methanol synthesis. As a consequence, bifunctionality of the Cu/ZnO catalyst such as metallic copper and acidic properties was required for this reaction. In this respect, the copper content（X） strongly affected the catalytic activity of the Cu/ZnO;catalysts, and accordingly, the Cu/ZnO;.5 catalyst with a high copper dispersion and sufficient acid sites exhibited the best catalytic performance in this reaction.

关键词： Low-temperature methanol synthesis Alcohol-assisted Bifunctionality Cu/ZnO catalysts copper content

Effects of copper content on the shell characteristics of hollow steel spheres manufactured using an advanced powder metallurgy technique

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2016年第4期23卷 434-441页

作者： Hamid Sazegaran Ali-Reza Kiani-Rashid Jalil Vahdati Khaki Department of Materials Science and Metallurgical Engineering Engineering Faculty Ferdowsi University of Mashhad

Metallic hollow spheres are used as base materials in the manufacture of hollow sphere structures and metallic foams. In this study, steel hollow spheres were successfully manufactured using an advanced powder metallurgy technique. The spheres＇ shells were characterized by optical microscopy in conjunction with microstructural image analysis software, scanning electron microscopy（SEM）, energy-dispersive X-ray spectroscopy（EDX）, and X-ray diffraction（XRD）. The microscopic evaluations revealed that the shells consist of sintered iron powder, sintered copper powder, sodium silicate, and porosity regions. In addition, the effects of copper content on various parameters such as shell defects, microcracks, thickness, and porosities were investigated. The results indicated that increasing the copper content results in decreases in the surface fraction of shell porosities and the number of microcracks and an increase in shell thickness.

关键词： steel hollow spheres powder metallurgy copper content shell characteristics

Investigation on the copper content of Matte Smelting Slag in Peirce-Smith Converter

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2001年第3期8卷 177-181页

作者： Chunlin Chen, Jiayun Zhang, Meng Bai, Shoukun Wei Metallurgy School, University of Science & Technology Beijing, Beijing 100083, China Guixi Smelter, Jiangxi copper Co. Ltd., Jiangxi 335424, China Metallurgy School Univ. of Sci. and Tech. Beijing Beijing 100083 China

The copper contents and its existing forms in the slags during the slag-making stage of Peirce-Smith converters in Guixi Smelter, Jiangxi Province, China have been investigated. The investigation was based on plant trials with the corresponding thermodynamic calculations and kinetic considerations. From the plant data, the total copper content in the slags was in the range of 2% to 8% (mass fraction). The mechanical entrainment of matte drops has been found to be the main cause of the copper loss. The suspension index, defined as the ratio of the mass fraction of copper in suspended matte drops in the slag to that in bulk of the matte phase, has been adopted to quantify the matte entrainment. The values of this parameter estimated in this work have been found mainly within a range of 2.5%-8.0%. The Fe3O4 content in the slag has been estimated to be the most important factor, among others, influencing the separation of slag with matte and, consequently, the copper loss from the slag.

关键词： Peirce-Smith converter copper content molten slag

Quench sensitivity of novel Al-Zn-Mg-Cu alloys containing different Cu contents

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2020年第12期39卷 1395-1401页

作者： Jin-Sheng Chen Xi-Wu Li Bai-Qing Xiong Yony-An Zhang Zhi-Hui Li Hong-Wei Yan Hong-Wei Liu Shu-Hui Huang State Key Laboratory of Nonferrous Metals and Processes General Research Institute for Nonferrous MetalsBeijing100088China

The effect of copper content on quench sensitivity in novel Al-Zn-Mg-Cu alloys containing high zinc content was investigated by Jominy end quench test.Electrical conductivity and hardness test,temperature collecting,and transmission electron microscopy(TEM)technique were adopted for the properties and microstructure characterization of three alloys with different copper contents.The results indicate that the electrical conductivity of all three alloys increases with the increase of distance from the quenched end,while the hardness shows an opposite trend.If the dropping of 10%hardness is defined as the critical evaluation standard of quenching,the depth of quenched layer of AlloysⅠ,Ⅱ,andⅢare 70,55,and 40 mm,respectively.The precipitation behavior on grain boundaries of three alloys is similar except for a little difference in size,while the size of precipitates in grains of AlloyⅢwith higher copper content is larger than those of the other two alloys at the same location.Considering all results,the stability of the supersaturated solid solution of AlloyⅢis lower than those of the other two alloys,meaning that AlloyⅢshows the highest quench sensitivity.Higher copper content leads to higher quench sensitivity in novel Al-Zn-Mg-Cu alloys with the same content of magnesium,zinc,and other trace elements.

关键词： Al-Zn-Mg-Cu alloy copper content Quench sensitivity Jominy end quench test Precipitates

Retrospective case-analysis of the magnetic resonance imaging characteristics in the brain of patients with Wilson disease

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2006年第6期1卷 529-532页

作者： Hong Li Kun You Baoming He Jiagui Su Jian Hong Changbin Quan Min Zhao Department of Radiology Second Hospital Affiliated to the General Hospital of Chinese PLA. Beijing 100091 China

BACKGROUND： Wilson disease （WD） damages liver, brain, kidney, cornea and nervous system severely. It is manifested in four ways： brain, liver, kidney and bone muscle. Whether or not magnetic resonance imaging （MRI） can clearly display the diseased region and range in brain of patient with WD, which provides imageological evidence for clinical practice, is unclear. OBJECTIVE： To observe the characteristics of MRI of brain in patient with SD, and analyze the correlation of diseased region with clinical symptoms. DESIGN ： Retrospective case-analysis SETTING： Department of Radiology, Second Hospital Affiliated to the General Hospital of Chinese PLA. PARTICIPANTS： Thirty-one patients, including 18 males and 13 females, with WD admitted to the Department of Neurology, Second Hospital Affiliated to the General Hospital of Chinese PLA between January 1999 and December 2005 ware retrieved. The involved patients presented serum copper oxidase （sCP） activity decreasing and/or caruloplasmin level decreasing and /or udnary copper content increasing; typical extrapyramidal symptoms and/or physical sign; abnormality showed by slit-lamp examination, Kayser-Fleischer dog positive. METHODS ：（1） All the involved patients underwent MRI examination. AGE 1.5T imaging equipment was used. Spin-echo sequence was adopted to perform T2 and T1 -weighed image at transverse axis level. Partial cases subjected to head scanning at coronal and/or sagittal level. Gd-DTPA with dosage of 0.1 mmol/kg was the strongest in 4 cases. （2） MRI charactenstics of patients with different clinical symptoms were observed. MAIN OUTCOME MEASURES： MRI detection results of patients with WD and MRI characteristics of patients with different clinical symptoms. RESULTS： Thirty-one patients with WD participated in the result analysis. （1） Imageologicat examination results： WD involved many regions in the brain： dorsal caudate putamen （n =28）, thalamencephalon（n =25）, mesencephalon （n =25）, globus pallidus （n =23）, pons（n =21 ）, posterior limb of interna

关键词： Wilson disease cerebral cortex caudate putamen magnetic resonance clinical practice result analysis caudate nucleus nervous system copper content serum copper