Modern warfare demands weapons capable of penetrating substantial structures,which presents sig-nificant challenges to the reliability of the electronic devices that are crucial to the weapon's perfor-mance.Due to...Modern warfare demands weapons capable of penetrating substantial structures,which presents sig-nificant challenges to the reliability of the electronic devices that are crucial to the weapon's perfor-mance.Due to miniaturization of electronic components,it is challenging to directly measure or numerically predict the mechanical response of small-sized critical interconnections in board-level packaging structures to ensure the mechanical reliability of electronic devices in projectiles under harsh working conditions.To address this issue,an indirect measurement method using the Bayesian regularization-based load identification was proposed in this study based on finite element(FE)pre-dictions to estimate the load applied on critical interconnections of board-level packaging structures during the process of projectile penetration.For predicting the high-strain-rate penetration process,an FE model was established with elasto-plastic constitutive models of the representative packaging ma-terials(that is,solder material and epoxy molding compound)in which material constitutive parameters were calibrated against the experimental results by using the split-Hopkinson pressure bar.As the impact-induced dynamic bending of the printed circuit board resulted in an alternating tensile-compressive loading on the solder joints during penetration,the corner solder joints in the edge re-gions experience the highest S11 and strain,making them more prone to failure.Based on FE predictions at different structural scales,an improved Bayesian method based on augmented Tikhonov regulariza-tion was theoretically proposed to address the issues of ill-posed matrix inversion and noise sensitivity in the load identification at the critical solder joints.By incorporating a wavelet thresholding technique,the method resolves the problem of poor load identification accuracy at high noise levels.The proposed method achieves satisfactorily small relative errors and high correlation coefficients in identifying the mechanical response of local interconnections in board-level packaging structures,while significantly balancing the smoothness of response curves with the accuracy of peak identification.At medium and low noise levels,the relative error is less than 6%,while it is less than 10%at high noise levels.The proposed method provides an effective indirect approach for the boundary conditions of localized solder joints during the projectile penetration process,and its philosophy can be readily extended to other scenarios of multiscale analysis for highly nonlinear materials and structures under extreme loading conditions.展开更多
The idea of Ku-band transceiver frequency conversion module design based on 3D micropackaging technology is proposed. By using the double frequency conversion technology,the dual transceiver circuit from Ku-band to L-...The idea of Ku-band transceiver frequency conversion module design based on 3D micropackaging technology is proposed. By using the double frequency conversion technology,the dual transceiver circuit from Ku-band to L-band is realized by combining with the local oscillator and the power control circuit to complete functions such as amplification, filtering and gain. In order to achieve the performance optimization and a high level of integration of the Ku-band monolithic microwave integrated circuits(MMIC) operating chip, the 3 D vertical interconnection micro-assembly technology is used. By stacking solder balls on the printed circuit board(PCB), the technology decreases the volume of the original transceiver to a miniaturized module. The module has a good electromagnetic compatibility through special structure designs. This module has the characteristics of miniaturization, low power consumption and high density, which is suitable for popularization in practical application.展开更多
In order to get an insight into the thermal characteristic and to evaluate the thermal reliability of the "System in Packaging"(SIP), a new solution of electronics packaging, a heat transfer model of SIP was...In order to get an insight into the thermal characteristic and to evaluate the thermal reliability of the "System in Packaging"(SIP), a new solution of electronics packaging, a heat transfer model of SIP was developed to predict the heat dissipation capacity and to investigate the effect of different factors on the tempe rature distribution in the electronics. The affecting parameters under consideration include the thermophysical properties of the substrates, the coefficient of convection heat transfer, the thickness of the chip, and the density of power dissipation. ALGOR, a kind of finite element analysis software,was used to do the model simulation. Based on the simulation and analysis of the heat conduction and convection resistance, criteria for the thermal design were established and possible measurement for enhancing power dissipation was provided. The results show that the heat transfer model provides a new and effective way to the thermal design and thermal analysis of SIP and to the mechanical analysis for the further investigation of SIP.展开更多
The electronic packaging shell with high silicon carbide aluminum-base composites was prepared by semi-solid thixoforming technique. The flow characteristic of the Si C particulate was analyzed. The microstructures of...The electronic packaging shell with high silicon carbide aluminum-base composites was prepared by semi-solid thixoforming technique. The flow characteristic of the Si C particulate was analyzed. The microstructures of different parts of the shell were observed by scanning electron microscopy and optical microscopy, and the thermophysical and mechanical properties of the shell were tested. The results show that there exists the segregation phenomenon between the Si C particulate and the liquid phase during thixoforming, the liquid phase flows from the shell, and the Si C particles accumulate at the bottom of the shell. The volume fraction of Si C decreases gradually from the bottom to the walls. Accordingly, the thermal conductivities of bottom center and walls are 178 and 164 W·m-1·K-1, the coefficients of thermal expansion(CTE) are 8.2×10-6 and 12.6×10-6 K-1, respectively. The flexural strength decreases slightly from 437 to 347 MPa. The microstructures and properties of the shell show gradient distribution.展开更多
China PrintingandPackagingStudy is an academicjournal ofspecializing in printing and packaging industries,found by China Academy of Printing Technology in 2009.It mainly reports monograph of the related theory and tec...China PrintingandPackagingStudy is an academicjournal ofspecializing in printing and packaging industries,found by China Academy of Printing Technology in 2009.It mainly reports monograph of the related theory and technology, research paper of theory and application and scientific results in printing and packaging fields.Including the technology of photoelectric imaging&digital imaging,theory and application research of character information and展开更多
An essential prerequisite of any genetherapy technique is the efficient and stable de-livery of transferred DNA into the target cell.Avariety of techniques are available for directly in-troducing DNA into eukaryotic c...An essential prerequisite of any genetherapy technique is the efficient and stable de-livery of transferred DNA into the target cell.Avariety of techniques are available for directly in-troducing DNA into eukaryotic cells,includingcoprecipitation with calcium phosphate,electroporation and microinjection. The efficien-cy of most of these physical transfection tech-niques is less than one in ten thousand, and展开更多
To elucidate the feasibility of retroviral mediatedtransfer of multidrug resistance gene (mdrl) intohematopoietic stem/progenitor cells, the CD34^+ cellswere isolated from bone marrow by using a high-gradient.magnetic...To elucidate the feasibility of retroviral mediatedtransfer of multidrug resistance gene (mdrl) intohematopoietic stem/progenitor cells, the CD34^+ cellswere isolated from bone marrow by using a high-gradient.magnetic cell sorting system, and the efficiency ofretroviral mediated gene transfer was studied.展开更多
Retroviral mediated gene transfer of humanglobin gene into hematopoietic stem cells is apromising approach for thalassemia gene therapy.Major problem of the transferred globin gene was lowlevel expression of the gene ...Retroviral mediated gene transfer of humanglobin gene into hematopoietic stem cells is apromising approach for thalassemia gene therapy.Major problem of the transferred globin gene was lowlevel expression of the gene with its proximal cis-acting sequence. The locus control region (LCR) ofthe human β-globin gene cluster consists of four majorDNase I hypersensitive sites (HS). When linked展开更多
Purpose: To explore whether the antisense RNA ofMHC-Ⅱ gene could inodulate the expression of HLA-DRgene and reduce the immunogenicity of cord blood (CB)cells.The authors transduced the antisense RNA ofMHC-Ⅱ gene int...Purpose: To explore whether the antisense RNA ofMHC-Ⅱ gene could inodulate the expression of HLA-DRgene and reduce the immunogenicity of cord blood (CB)cells.The authors transduced the antisense RNA ofMHC-Ⅱ gene into CD34 CB stem/progenitor cells.Methods: A retroviral vector encoding antisense RNA ofHLA-DR gene was constructed by molecular cloningtechnique and transducted into packaging cells line PA317by lipofectin. The high titer, helper-free,展开更多
Objective: In order to coordinately express amarker gene and therapeutic genes in one vector, apolycistronic retroviral vector was constructed withthe internal ribosome entry site from encephalo-myocarditis and polio ...Objective: In order to coordinately express amarker gene and therapeutic genes in one vector, apolycistronic retroviral vector was constructed withthe internal ribosome entry site from encephalo-myocarditis and polio virus, which was able to expressthree different genes simultaneously. Methods: Thevector used mouse moloney leukemia virus sequencesfor viral expression and packaging functions展开更多
Stem cell factor (SCF) is a novel growth factor thatinfluences the growth and development of hematopoieticcells, germ cells and melanocytes. To explore
In order to increase the expression of mdrl genetransfectcd using retroviral vcctors, we constructedtwo retroviral vectors (LmdrlSN and MSCV-mdrl)containing mdrl cDNA and compared the expressionof mdrl gene with anoth...In order to increase the expression of mdrl genetransfectcd using retroviral vcctors, we constructedtwo retroviral vectors (LmdrlSN and MSCV-mdrl)containing mdrl cDNA and compared the expressionof mdrl gene with another vector pHamdrl/A(Pastan et al. Proc Natl Acad Sci USA 85: 4486,1986) in NIH.3T3 cells. The LmdrlSN was made展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.52475166,52175148)the Regional Collaboration Project of Shanxi Province(Grant No.202204041101044).
文摘Modern warfare demands weapons capable of penetrating substantial structures,which presents sig-nificant challenges to the reliability of the electronic devices that are crucial to the weapon's perfor-mance.Due to miniaturization of electronic components,it is challenging to directly measure or numerically predict the mechanical response of small-sized critical interconnections in board-level packaging structures to ensure the mechanical reliability of electronic devices in projectiles under harsh working conditions.To address this issue,an indirect measurement method using the Bayesian regularization-based load identification was proposed in this study based on finite element(FE)pre-dictions to estimate the load applied on critical interconnections of board-level packaging structures during the process of projectile penetration.For predicting the high-strain-rate penetration process,an FE model was established with elasto-plastic constitutive models of the representative packaging ma-terials(that is,solder material and epoxy molding compound)in which material constitutive parameters were calibrated against the experimental results by using the split-Hopkinson pressure bar.As the impact-induced dynamic bending of the printed circuit board resulted in an alternating tensile-compressive loading on the solder joints during penetration,the corner solder joints in the edge re-gions experience the highest S11 and strain,making them more prone to failure.Based on FE predictions at different structural scales,an improved Bayesian method based on augmented Tikhonov regulariza-tion was theoretically proposed to address the issues of ill-posed matrix inversion and noise sensitivity in the load identification at the critical solder joints.By incorporating a wavelet thresholding technique,the method resolves the problem of poor load identification accuracy at high noise levels.The proposed method achieves satisfactorily small relative errors and high correlation coefficients in identifying the mechanical response of local interconnections in board-level packaging structures,while significantly balancing the smoothness of response curves with the accuracy of peak identification.At medium and low noise levels,the relative error is less than 6%,while it is less than 10%at high noise levels.The proposed method provides an effective indirect approach for the boundary conditions of localized solder joints during the projectile penetration process,and its philosophy can be readily extended to other scenarios of multiscale analysis for highly nonlinear materials and structures under extreme loading conditions.
文摘The idea of Ku-band transceiver frequency conversion module design based on 3D micropackaging technology is proposed. By using the double frequency conversion technology,the dual transceiver circuit from Ku-band to L-band is realized by combining with the local oscillator and the power control circuit to complete functions such as amplification, filtering and gain. In order to achieve the performance optimization and a high level of integration of the Ku-band monolithic microwave integrated circuits(MMIC) operating chip, the 3 D vertical interconnection micro-assembly technology is used. By stacking solder balls on the printed circuit board(PCB), the technology decreases the volume of the original transceiver to a miniaturized module. The module has a good electromagnetic compatibility through special structure designs. This module has the characteristics of miniaturization, low power consumption and high density, which is suitable for popularization in practical application.
文摘In order to get an insight into the thermal characteristic and to evaluate the thermal reliability of the "System in Packaging"(SIP), a new solution of electronics packaging, a heat transfer model of SIP was developed to predict the heat dissipation capacity and to investigate the effect of different factors on the tempe rature distribution in the electronics. The affecting parameters under consideration include the thermophysical properties of the substrates, the coefficient of convection heat transfer, the thickness of the chip, and the density of power dissipation. ALGOR, a kind of finite element analysis software,was used to do the model simulation. Based on the simulation and analysis of the heat conduction and convection resistance, criteria for the thermal design were established and possible measurement for enhancing power dissipation was provided. The results show that the heat transfer model provides a new and effective way to the thermal design and thermal analysis of SIP and to the mechanical analysis for the further investigation of SIP.
文摘The electronic packaging shell with high silicon carbide aluminum-base composites was prepared by semi-solid thixoforming technique. The flow characteristic of the Si C particulate was analyzed. The microstructures of different parts of the shell were observed by scanning electron microscopy and optical microscopy, and the thermophysical and mechanical properties of the shell were tested. The results show that there exists the segregation phenomenon between the Si C particulate and the liquid phase during thixoforming, the liquid phase flows from the shell, and the Si C particles accumulate at the bottom of the shell. The volume fraction of Si C decreases gradually from the bottom to the walls. Accordingly, the thermal conductivities of bottom center and walls are 178 and 164 W·m-1·K-1, the coefficients of thermal expansion(CTE) are 8.2×10-6 and 12.6×10-6 K-1, respectively. The flexural strength decreases slightly from 437 to 347 MPa. The microstructures and properties of the shell show gradient distribution.
文摘China PrintingandPackagingStudy is an academicjournal ofspecializing in printing and packaging industries,found by China Academy of Printing Technology in 2009.It mainly reports monograph of the related theory and technology, research paper of theory and application and scientific results in printing and packaging fields.Including the technology of photoelectric imaging&digital imaging,theory and application research of character information and
文摘An essential prerequisite of any genetherapy technique is the efficient and stable de-livery of transferred DNA into the target cell.Avariety of techniques are available for directly in-troducing DNA into eukaryotic cells,includingcoprecipitation with calcium phosphate,electroporation and microinjection. The efficien-cy of most of these physical transfection tech-niques is less than one in ten thousand, and
文摘To elucidate the feasibility of retroviral mediatedtransfer of multidrug resistance gene (mdrl) intohematopoietic stem/progenitor cells, the CD34^+ cellswere isolated from bone marrow by using a high-gradient.magnetic cell sorting system, and the efficiency ofretroviral mediated gene transfer was studied.
文摘Retroviral mediated gene transfer of humanglobin gene into hematopoietic stem cells is apromising approach for thalassemia gene therapy.Major problem of the transferred globin gene was lowlevel expression of the gene with its proximal cis-acting sequence. The locus control region (LCR) ofthe human β-globin gene cluster consists of four majorDNase I hypersensitive sites (HS). When linked
文摘Purpose: To explore whether the antisense RNA ofMHC-Ⅱ gene could inodulate the expression of HLA-DRgene and reduce the immunogenicity of cord blood (CB)cells.The authors transduced the antisense RNA ofMHC-Ⅱ gene into CD34 CB stem/progenitor cells.Methods: A retroviral vector encoding antisense RNA ofHLA-DR gene was constructed by molecular cloningtechnique and transducted into packaging cells line PA317by lipofectin. The high titer, helper-free,
文摘Objective: In order to coordinately express amarker gene and therapeutic genes in one vector, apolycistronic retroviral vector was constructed withthe internal ribosome entry site from encephalo-myocarditis and polio virus, which was able to expressthree different genes simultaneously. Methods: Thevector used mouse moloney leukemia virus sequencesfor viral expression and packaging functions
文摘Stem cell factor (SCF) is a novel growth factor thatinfluences the growth and development of hematopoieticcells, germ cells and melanocytes. To explore
文摘In order to increase the expression of mdrl genetransfectcd using retroviral vcctors, we constructedtwo retroviral vectors (LmdrlSN and MSCV-mdrl)containing mdrl cDNA and compared the expressionof mdrl gene with another vector pHamdrl/A(Pastan et al. Proc Natl Acad Sci USA 85: 4486,1986) in NIH.3T3 cells. The LmdrlSN was made
