Green and low carbon promote the application and development of light-weight materials in body-in-white. Large-scale die-casting Al alloy (DCAA) and high-strength thermo-formed steel sheet (TFSS) have put forward high...Green and low carbon promote the application and development of light-weight materials in body-in-white. Large-scale die-casting Al alloy (DCAA) and high-strength thermo-formed steel sheet (TFSS) have put forward higher requirements for the application of joining technology of high-strength steel/Al dissimilar materials. Taking the new die-casting Al alloy body as an example, this paper systematically studies the progress of the latest joining methods of steel/Al dissimilar material with combination of two-layer plate and three-layer plate. By analyzing the joining technologies such as FSPR, RES, FDS and SPR, the technology and process characteristics of steel/Al dissimilar material joining are studied, and the joining technical feasibility and realization means of different material combination of the body are analyzed. The conditions of material combination, material thickness, material strength, flange height, preformed holes and joint spacing for achieving high-quality joining are given. The FSPR joining technology is developed and tested in order to meet with the joining of parts with DCAA and TFSS, especially for the joining of three-layer plates with them. It finds the method and technical basis for the realization of high quality joining of dissimilar materials, provides the early conditions for the application of large DCAA and TFSS parts in body-in-white, and meets the design requirements of new energy body. .展开更多
Spot weld models are widely used in finite element analysis（FEA） of automotive body in white（BIW） to predict static,dynamic,durability and other characteristics of automotive BIW.However,few researches are done on...Spot weld models are widely used in finite element analysis（FEA） of automotive body in white（BIW） to predict static,dynamic,durability and other characteristics of automotive BIW.However,few researches are done on evaluation of the validity of these spot weld models in structural dynamic analysis of BIW.To evaluate the validity and accuracy of spot weld models in structural dynamic analysis of BIW,two object functions,error function and deviation function,are introduced innovatively.Modal analysis of Two-panel and Double-hat structures,which are the dominated structures in BIW,is conducted,and the values of these two object functions are obtained.Based on the values of object functions,the validity of these spot weld models are evaluated.It is found that the area contact method（ACM2） and weld element connection（CWELD） can give more precise prediction in modal analysis of these two classical structures,thus are more applicable to structural dynamic analysis of automotive BIW.Modal analysis of a classical BIW is performed,which further confirms this evaluation.The error function and deviation function proposed in this research can give guidance on the adaptability of spot weld models in structural dynamic analysis of BIW.And this evaluation method can also be adopted in evaluation of other finite element models in static,dynamic and other kinds of analysis for automotive structures.展开更多
Cattle production is integral to the people of Africa and her economy. To <span style="font-family:Verdana;">improve cattle productivity, there is a need to inculcate molecular mark</span><spa...Cattle production is integral to the people of Africa and her economy. To <span style="font-family:Verdana;">improve cattle productivity, there is a need to inculcate molecular mark</span><span style="font-family:Verdana;">er-assisted selection into current breeding practices. In this study, we investigated, in </span><span style="font-family:Verdana;">White Fulani and Muturu cattle breeds, polymorphism of two candidate</span><span style="font-family:Verdana;"> genes (Smoothened—</span><i><span style="font-family:Verdana;">SMO</span></i><span style="font-family:Verdana;"> and Lipase Maturation Factor 1—</span><i><span style="font-family:Verdana;">LMF</span></i><span style="font-family:Verdana;">1</span><span style="font-family:Verdana;">) that have been reported to influence body size in cattle. The </span><i><span style="font-family:Verdana;">SMO</span></i><span style="font-family:Verdana;"> gene encodes for the SMO </span><span style="font-family:Verdana;">(smoothened) receptor protein;a membrane signal transducer that plays a</span><span style="font-family:Verdana;"> role in the control of bone formation and adipogenesis. </span><i><span style="font-family:Verdana;">LMF</span></i><span style="font-family:Verdana;">1 </span><span style="font-family:Verdana;">encodes for the </span><span style="font-family:Verdana;">LMF1 protein which regulates post-translational maturation of vascular li</span><span style="font-family:Verdana;">pases. Desired regions of the genes were amplified and genotyped by direct </span><span style="font-family:Verdana;">DNA sequencing or Polymerase chain reaction—Restriction Fragment</span><span style="font-family:Verdana;"> Length </span><span style="font-family:Verdana;">Polymorphism. For association study, linear body measurements traits</span><span style="font-family:Verdana;"> (BMTs) that can be used to predict body size were measured on each animal and values of BMTs measured were compared between both breeds. Very significant (P < 0.001) differences, in favour of White Fulani, were observed for all the BMTs compared. Six (6) previously reported SNP (G21234C, C22424T and C22481T, T22939C, C23329T and T23458G) were found on the </span><i><span style="font-family:Verdana;">SMO</span></i><span> </span><span style="font-family:Verdana;">while </span><i><span style="font-family:Verdana;">LMF</span></i><span style="font-family:Verdana;">1</span><span style="font-family:Verdana;"> was monomorphic at the expected (T > C) exon 4 mutation site. Association analysis revealed that polymorphism on G21234C, C22424T, T22939C and T23458G loci significantly affected BMTs (P < 0.05 or 0.01) in both cattle breeds. The outcome of this study showed that </span><i><span style="font-family:Verdana;">SMO</span></i><span style="font-family:Verdana;"> gene could be a useful </span><span style="font-family:Verdana;">candidate gene to facilitate marker assisted selection for body size while </span><i><span style="font-family:Verdana;">LMF</span></i><span style="font-family:Verdana;">1</span><span style="font-family:Verdana;"> is monomorphic in the cattle breeds.</span>展开更多
A new high accuracy 6D ( Dimension ) wide range measuring technology and the method of coordinate transformations have been developed in a project for automobile body-in- white measurement in Michigan , U S A . The re...A new high accuracy 6D ( Dimension ) wide range measuring technology and the method of coordinate transformations have been developed in a project for automobile body-in- white measurement in Michigan , U S A . The requirements and the special features about the measured objective are mainly stated. The main instruments used in the project are introduced. The 6D measuring system , the method for coordinate transformations and the design of 3D optical target with hollow tetrahedron are described in detail . The 6D system and the technology can be certainly used in many other kinds of geometric mea- suring projects .展开更多
文摘Green and low carbon promote the application and development of light-weight materials in body-in-white. Large-scale die-casting Al alloy (DCAA) and high-strength thermo-formed steel sheet (TFSS) have put forward higher requirements for the application of joining technology of high-strength steel/Al dissimilar materials. Taking the new die-casting Al alloy body as an example, this paper systematically studies the progress of the latest joining methods of steel/Al dissimilar material with combination of two-layer plate and three-layer plate. By analyzing the joining technologies such as FSPR, RES, FDS and SPR, the technology and process characteristics of steel/Al dissimilar material joining are studied, and the joining technical feasibility and realization means of different material combination of the body are analyzed. The conditions of material combination, material thickness, material strength, flange height, preformed holes and joint spacing for achieving high-quality joining are given. The FSPR joining technology is developed and tested in order to meet with the joining of parts with DCAA and TFSS, especially for the joining of three-layer plates with them. It finds the method and technical basis for the realization of high quality joining of dissimilar materials, provides the early conditions for the application of large DCAA and TFSS parts in body-in-white, and meets the design requirements of new energy body. .
基金supported by National Natural Science Foundation of China(Grant No.10772060)Heilongjiang Provincial Natural Science Foundation with Excellent Young Investigators of China(GrantNo.JC2006-13)
文摘Spot weld models are widely used in finite element analysis（FEA） of automotive body in white（BIW） to predict static,dynamic,durability and other characteristics of automotive BIW.However,few researches are done on evaluation of the validity of these spot weld models in structural dynamic analysis of BIW.To evaluate the validity and accuracy of spot weld models in structural dynamic analysis of BIW,two object functions,error function and deviation function,are introduced innovatively.Modal analysis of Two-panel and Double-hat structures,which are the dominated structures in BIW,is conducted,and the values of these two object functions are obtained.Based on the values of object functions,the validity of these spot weld models are evaluated.It is found that the area contact method（ACM2） and weld element connection（CWELD） can give more precise prediction in modal analysis of these two classical structures,thus are more applicable to structural dynamic analysis of automotive BIW.Modal analysis of a classical BIW is performed,which further confirms this evaluation.The error function and deviation function proposed in this research can give guidance on the adaptability of spot weld models in structural dynamic analysis of BIW.And this evaluation method can also be adopted in evaluation of other finite element models in static,dynamic and other kinds of analysis for automotive structures.
文摘Cattle production is integral to the people of Africa and her economy. To <span style="font-family:Verdana;">improve cattle productivity, there is a need to inculcate molecular mark</span><span style="font-family:Verdana;">er-assisted selection into current breeding practices. In this study, we investigated, in </span><span style="font-family:Verdana;">White Fulani and Muturu cattle breeds, polymorphism of two candidate</span><span style="font-family:Verdana;"> genes (Smoothened—</span><i><span style="font-family:Verdana;">SMO</span></i><span style="font-family:Verdana;"> and Lipase Maturation Factor 1—</span><i><span style="font-family:Verdana;">LMF</span></i><span style="font-family:Verdana;">1</span><span style="font-family:Verdana;">) that have been reported to influence body size in cattle. The </span><i><span style="font-family:Verdana;">SMO</span></i><span style="font-family:Verdana;"> gene encodes for the SMO </span><span style="font-family:Verdana;">(smoothened) receptor protein;a membrane signal transducer that plays a</span><span style="font-family:Verdana;"> role in the control of bone formation and adipogenesis. </span><i><span style="font-family:Verdana;">LMF</span></i><span style="font-family:Verdana;">1 </span><span style="font-family:Verdana;">encodes for the </span><span style="font-family:Verdana;">LMF1 protein which regulates post-translational maturation of vascular li</span><span style="font-family:Verdana;">pases. Desired regions of the genes were amplified and genotyped by direct </span><span style="font-family:Verdana;">DNA sequencing or Polymerase chain reaction—Restriction Fragment</span><span style="font-family:Verdana;"> Length </span><span style="font-family:Verdana;">Polymorphism. For association study, linear body measurements traits</span><span style="font-family:Verdana;"> (BMTs) that can be used to predict body size were measured on each animal and values of BMTs measured were compared between both breeds. Very significant (P < 0.001) differences, in favour of White Fulani, were observed for all the BMTs compared. Six (6) previously reported SNP (G21234C, C22424T and C22481T, T22939C, C23329T and T23458G) were found on the </span><i><span style="font-family:Verdana;">SMO</span></i><span> </span><span style="font-family:Verdana;">while </span><i><span style="font-family:Verdana;">LMF</span></i><span style="font-family:Verdana;">1</span><span style="font-family:Verdana;"> was monomorphic at the expected (T > C) exon 4 mutation site. Association analysis revealed that polymorphism on G21234C, C22424T, T22939C and T23458G loci significantly affected BMTs (P < 0.05 or 0.01) in both cattle breeds. The outcome of this study showed that </span><i><span style="font-family:Verdana;">SMO</span></i><span style="font-family:Verdana;"> gene could be a useful </span><span style="font-family:Verdana;">candidate gene to facilitate marker assisted selection for body size while </span><i><span style="font-family:Verdana;">LMF</span></i><span style="font-family:Verdana;">1</span><span style="font-family:Verdana;"> is monomorphic in the cattle breeds.</span>
文摘A new high accuracy 6D ( Dimension ) wide range measuring technology and the method of coordinate transformations have been developed in a project for automobile body-in- white measurement in Michigan , U S A . The requirements and the special features about the measured objective are mainly stated. The main instruments used in the project are introduced. The 6D measuring system , the method for coordinate transformations and the design of 3D optical target with hollow tetrahedron are described in detail . The 6D system and the technology can be certainly used in many other kinds of geometric mea- suring projects .
