| 1. |
- Chen, S., et al.
(författare)
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Coffin-Mansson equation of Sn-4.0Ag-0.5Cu solder joint
- 2009
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Ingår i: Soldering and Surface Mount Technology. - : Emerald. - 1758-6836 .- 0954-0911. ; 21:2, s. 48-54
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of this paper is to fit Coffin-Manson equation of Sn-4.0Ag-0.5Cu lead free solder joint by using results of solders joint reliability test and finite element analysis. Also to present a novel device for solder joint reliability test. Design/methodology/approach: Two-points bending test of Sn-4.0Ag-0.5Cu lead free solder joint was carried out at three deflection levels by using a special bending tester that can control displacement exactly by a cam system. The failure criterion was defined as resistance of solder joint getting 10 percent increase. The X-section was done for all failure samples to observe crack initiation and propagation in solder joint. Finite element analysis was presented with ANSYS for obtaining shear strain range, analyzing distribution of stress and strain and supporting experimental results. Findings: The experimental results indicate that the fatigue life decreased obviously with the displacement increased. By using optical microscope and SEM photographs, two kinds of failure mode were found in solder joint. The majority failure mode took place at the bottom corner of solder joint under the termination of resistor initially, and propagated into the solder matrix. Another failure mode was delamination. It appeared at the interface between the termination of resistor and its ceramic body. The distribution status of stress and strain in solder joint and the calculation results of shear strain range at different deflection levels were obtained from simulation result. The Coffin-Manson equation of Sn-4.0Ag-0.5Cu lead free solder joint was fitted by combining experimental data with result of finite element analysis. Originality/value: This paper presents Coffin-Manson equation of Sn-4.0Ag-0.5Cu solder joint with two-points bending test. An effective and economical device was designed and applied.
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| 2. |
- Hsieh, Yves S-Y, et al.
(författare)
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Structure and bioactivity of the polysaccharides in medicinal plant Dendrobium huoshanense
- 2008
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Ingår i: Bioorganic & Medicinal Chemistry. - : Elsevier. - 0968-0896 .- 1464-3391. ; 16:11, s. 6054-68
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Tidskriftsartikel (refereegranskat)abstract
- Detailed structures of the active polysaccharides extracted from the leaf and stem cell walls and mucilage of Dendrobium huoshanense are determined by using various techniques, including chromatographic, spectroscopic, chemical, and enzymatic methods. The mucilage polysaccharide exhibits specific functions in activating murine splenocytes to produce several cytokines including IFN-gamma, IL-10, IL-6, and IL-1alpha, as well as hematopoietic growth factors GM-CSF and G-CSF. However, the deacetylated mucilage obtained from an alkaline treatment fails to induce cytokine production. The structure and bioactivity of mucilage components are validated by further fractionation. This is the first study that provides clear evidence for the structure and activity relationship of the polysaccharide in D. huoshanense.
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| 3. |
- Sun, Peng, 1979, et al.
(författare)
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High temperature aging study of intermetallic compound formation of Sn-3,5Ag and Sn-4.0Ag-0,5Cu solders on electroless Ni(P) metallization
- 2006
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388. ; 425:1-2, s. 191-199
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Tidskriftsartikel (refereegranskat)abstract
- The Sn-3.5Ag and Sn-4.0Ag-0.5Cu solders on Au/electroless Ni(P) metallization exhibited different interfacial morphologies after high temperature storage (HTS) at 150 °C. Ni 3 Sn 4 intermetallic compounds (IMCs) were found in the Sn-Ag system, while for the Sn-Ag-Cu system the IMCs consisted of two kinds of interfacial reactions. For the Sn-3.5Ag solder, the Ni 3 Sn 4 IMC particles lost adhesion/contact to the electroless Ni(P) layer and clear gap was observed in the samples after high temperature storage (HTS) aging for 1000 h. In the Sn-4.0Ag-0.5Cu solder joint, both (Cu,Ni) 6 Sn 5 and (Ni,Cu) 3 Sn 4 compounds were observed after HTS aging. Since the difference in nucleation site and growth rate for kinds of IMCs, (Cu,Ni) 6 Sn 5 was observed at top and (Ni,Cu) 3 Sn 4 at bottom when the interfacial compound layer became thicker as a function of thermal aging. Some voids were found between the electroless Ni(P) interface and the Sn-Ag solder after 168 and 500 h of thermal aging, while the clear gap between the solder and the Ni layer existed after 1000 h aging. The formation mechanism for this gap could be the interconnection and growth of the voids. In the Sn-Ag-Cu system, voids were found inside the Sn-Ni-Cu ternary interfacial compounds after 500 and 1000 h. The formation mechanism for these voids was thought to be Kirkendall effect or etching process. The interfacial layer of Sn-Ag-Cu solder on electroless Ni(P) coating showed the better thermal stable than eutectic Sn-Ag solder. © 2006 Elsevier B.V. All rights reserved.
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| 4. |
- Wei, Jian-Feng, et al.
(författare)
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Formation of Kv2.1-FAK complex as a mechanism of FAK activation, cell polarization and enhanced motility
- 2008
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Ingår i: Journal of Cellular Physiology. - : Wiley. - 0021-9541 .- 1097-4652. ; 217:2, s. 544-557
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Tidskriftsartikel (refereegranskat)abstract
- Focal adhesion kinase (FAK) plays key roles in cell adhesion and migration. We now report that the delayed rectifier Kv2.1 potassium channel, through its LD-like motif in N-terminus, may interact with FAK and enhance phosphorylation of FAK(397) and FAK(576/577) Overlapping distribution of Kv2.1 and FAK was observed on soma and proximal dendrites of cortical neurons. FAK expression promotes a polarized membrane distribution of the Kv2.1 channel. In Kv2.1-transfected CHO cells, formation of the Kv2.1-FAK complex was stimulated by fibronectin/integrin and inhibited by the K channel blocker tetraethylammonium (TEA). FAK phosphorylation was minimized by shRNA knockdown of the Kv2.1 channel, point mutations of the N-terminus, and TEA, respectively. Cell migration morphology was altered by Kv2.1 knockdown or TEA, hindering cell migration activity. In wound healing tests in vitro and a traumatic injury animal model, Kv2.1 expression and co-localization of Kv2.1 and FAK significantly enhanced directional cell migration and wound closure. It is suggested that the Kv2.1 channel may function as a promoting signal for FAK activation and cell motility.
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| 5. |
- Wei, P K, et al.
(författare)
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Beaming effect of optical near-field in multiple metallic slits with nanometric linewidth and micrometer pitch
- 2005
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Ingår i: Optics Communications. - : Elsevier BV. - 0030-4018. ; 253:1-3, s. 198-204
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Tidskriftsartikel (refereegranskat)abstract
- The beaming effect and interference patterns on the exit surface of multiple nano metallic slits with micrometer pitch were observed by scanning near-field optical microscopy. The near-field light intensity for multiple slits had a longer propagation tail and a smaller diverging angle as compared to that in a single slit. From finite-difference time-domain calculations, we verify that these fringe patterns come from the interference effect of longitudinal electric field, which is propagating along the surface. The beaming light in the slit openings is also attributed to the addition of longitudinal fields.
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| 6. |
- Bailey, C., et al.
(författare)
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Coffin-Manson constant determination for a Sn-8Zn-3Bi Lead-Free Solder Joint
- 2006
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Ingår i: Soldering and Surface Mount Technology. - : Emerald. - 1758-6836 .- 0954-0911. ; 18:2, s. 4-11
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Tidskriftsartikel (refereegranskat)abstract
- Purpose To determine the Coffin-Manson (CM) equation constants for fatigue life estimation of Sn-8Zn-3Bi solder joints, since Sn-8Zn-3Bi solder has a melting temperature of around 199°C which is close to that of the conventional Sn-Pb solder which has previously been used in the electronics assembly industry. Design/methodology/approach Three dimensional finite element (FE) simulation analysis was used for comparison with the experimentally measured data and to determine the CM constants. Low cycle fatigue tests and FE simulations were carried out for these lead-free solder joints, and eutectic Sn-37Pb solder was used as a reference. Findings The CM equation for Sn-8Zn-3Bi solder joints was fitted to the lifetimes measured and the shear strains simulated. The constants were determined to be 0.0294 for C, the proportional constant, and for the fatigue exponent, β, −2.833. Originality/value The CM equation can now be used to predict the reliability of Sn-8Zn-3Bi solder joints in electronics assembly and the knowledge base for the properties of the Sn-Zn solder system has been increased.
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| 7. |
- Birney, Ewan, et al.
(författare)
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Identification and analysis of functional elements in 1% of the human genome by the ENCODE pilot project
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 447:7146, s. 799-816
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Tidskriftsartikel (refereegranskat)abstract
- We report the generation and analysis of functional data from multiple, diverse experiments performed on a targeted 1% of the human genome as part of the pilot phase of the ENCODE Project. These data have been further integrated and augmented by a number of evolutionary and computational analyses. Together, our results advance the collective knowledge about human genome function in several major areas. First, our studies provide convincing evidence that the genome is pervasively transcribed, such that the majority of its bases can be found in primary transcripts, including non-protein-coding transcripts, and those that extensively overlap one another. Second, systematic examination of transcriptional regulation has yielded new understanding about transcription start sites, including their relationship to specific regulatory sequences and features of chromatin accessibility and histone modification. Third, a more sophisticated view of chromatin structure has emerged, including its inter-relationship with DNA replication and transcriptional regulation. Finally, integration of these new sources of information, in particular with respect to mammalian evolution based on inter- and intra-species sequence comparisons, has yielded new mechanistic and evolutionary insights concerning the functional landscape of the human genome. Together, these studies are defining a path for pursuit of a more comprehensive characterization of human genome function.
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| 8. |
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| 9. |
- Cheng, M.H., et al.
(författare)
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Growth and characterization of Ge nanostructures selectively grown on patterned Si
- 2008
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Ingår i: Thin Solid Films. - : Elsevier Science B.V., Amsterdam.. - 0040-6090 .- 1879-2731. ; 517:1, s. 57-61
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Tidskriftsartikel (refereegranskat)abstract
- By utilizing different distribution of strain fields around the edges of oxide, which are dominated by a series of sizes of oxide-patterned windows, long-range ordered self-assembly Ge nanostructures, such as nano-rings, nano-disks and nano-dots, were selectively grown by ultra high vacuum chemical vapor deposition (UHV-CVD) on Si (001) substrates. High-resolution double-crystal symmetrical omega/2 theta scans and two-dimensional reciprocal space mapping (2D-RSM) technologies employing the triple axis X-ray diffractometry have been used to evaluate the quality and strain status of as-deposited as well as in-situ annealed Ge nanostructures. Furthermore, we also compare the quality and strain status of Ge epilayers grown on planar unpatterned Si substrates. It was found that the quality of all Ge epitaxial structures is improved after in-situ annealing process and the quality of Ge nano-disk structures is better than that of Ge epilayers; on planar unpatterned Si substrates, because oxide sidewalls are effective dislocation sinks. We also noted that the degree of relaxation for as-deposited Ge epilayers on planar unpatterned Si substrates is less than that for as-deposited Ge nano-disk structures. After in-situ annealing process,all Ge epitaxial structures are almost at full relaxation whatever Ge epitaxial structures grew on patterned or unpatterned Si substrates.
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| 10. |
- Hering, Bernhard J., et al.
(författare)
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Prolonged diabetes reversal after intraportal xenotransplantation of wild-type porcine islets in immunosuppressed nonhuman primates
- 2006
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Ingår i: Nature Medicine. - : Nature Publishing Group. - 1078-8956 .- 1546-170X. ; 12:3, s. 301-303
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Tidskriftsartikel (refereegranskat)abstract
- Cell-based diabetes therapy requires an abundant cell source. Here, we report reversal of diabetes for more than 100 d in cynomolgus macaques after intraportal transplantation of cultured islets from genetically unmodified pigs without Gal-specific antibody manipulation. Immunotherapy with CD25-specific and CD154-specific monoclonal antibodies, FTY720 (or tacrolimus), everolimus and leflunomide suppressed indirect activation of T cells, elicitation of non-Gal pig-specific IgG antibody, intragraft expression of proinflammatory cytokines and invasion of infiltrating mononuclear cells into islets.
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| 11. |
- Hsu, Li-Han, 1981, et al.
(författare)
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Fabrication process and 110 GHz measurement result of MS-to-CPW RF-via transition for RF-MEMS devices packaging applications
- 2009
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Ingår i: 2009 International Conference on Compound Semiconductor Manufacturing Technology, CS MANTECH 2009. - 9781893580138
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Konferensbidrag (refereegranskat)abstract
- This paper presents the fabrication process of RF-via (0-level) and flip-chip bump (1-level) transitions for applications of packaging MS (microstrip) RF-MEMS devices. The interconnect structure with MS-to-CPW transition between GaAs MEMS substrate and Al2O3 motherboard was in-house fabricated. A novel fabrication process for RF-MEMS packaging is in detail. After fabrication, the samples were measured up to 110 GHz using on-wafer probing measurement. From the measured results, the insertion loss of entire interconnect structure is better than -2 dB up to 100 GHz, documenting the feasibility for millimeter-wave RF-MEMS devices packaging applications.
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| 12. |
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| 13. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes
- 2008
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Ingår i: Autophagy. - : Landes Bioscience. - 1554-8627 .- 1554-8635. ; 4:2, s. 151-175
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Forskningsöversikt (refereegranskat)abstract
- Research in autophagy continues to accelerate,1 and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.2,3 There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.
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| 14. |
- Luo, G, et al.
(författare)
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Suppressing phosphorus diffusion in germanium by carbon incorporation
- 2005
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Ingår i: Electronics Letters. - : Iet. - 0013-5194 .- 1350-911X. ; 41:24, s. 1354-1355
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Tidskriftsartikel (refereegranskat)abstract
- A problem in the Ge MOSFET process is that the phosphor-us for n-type doping in Ge diffuses very fast. It is very difficult to form the shallow source/drain p-n junctions. It is reported, for the first time, that the phosphorus diffusion in Ge during activation (or annealing) can be suppressed effectively owing to carbon incorporation.
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| 15. |
- Nath, Swapan K., et al.
(författare)
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A nonsynonymous functional variant in integrin-alpha(M) (encoded by ITGAM) is associated with systemic lupus erythematosus
- 2008
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 40:2, s. 152-154
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Tidskriftsartikel (refereegranskat)abstract
- We identified and replicated an association between ITGAM (CD11b) at 16p11.2 and risk of systemic lupus erythematosus (SLE) in 3,818 individuals of European descent. The strongest association was at a nonsynonymous SNP, rs1143679 (P = 1.7 x 10(-17), odds ratio = 1.78). We further replicated this association in two independent samples of individuals of African descent (P = 0.0002 and 0.003; overall meta-analysis P = 6.9 x 10(-22)). The genetic association between ITGAM and SLE implicates the alpha(M)beta2-integrin adhesion pathway in disease development.
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| 16. |
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| 17. |
- Sun, Peng, 1979, et al.
(författare)
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Intermetallic Compound Formation in Sn-Co-Cu, Sn-Ag-Cu and Eutectic Sn-Cu Solder Joints on Electroless Ni(P) Immersion Au Surface Finish After Reflow Soldering
- 2006
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Ingår i: Materials Science & Engineering B: Solid-State Materials for Advanced Technology. - : Elsevier BV. - 0921-5107. ; 135:2, s. 134-140
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Tidskriftsartikel (refereegranskat)abstract
- The interfacial reactions between Sn-0.4Co-0.7Cu eutectic alloy and immersion Au/electroless Ni(P)/Cu substrate were investigated after reflow soldering at 260 °C for 2 min. Common Sn-4.0Ag-0.5Cu and eutectic Sn-0.7Cu solders were used as reference. Two types of intermetallic compounds (IMC) were found in the solder matrix of the Sn-0.4Co-0.7Cu alloy, namely coarser CoSn 2 and finer Cu 6 Sn 5 particles, while only one ternary (Cu, Ni) 6 Sn 5 interfacial compound was detected between the solder alloy and the electroless nickel and immersion gold (ENIG) coated substrate. The same trend was also observed for the Sn-Ag-Cu and Sn-Cu solder joints. Compared with the CoSn 2 particles found in the Sn-Co-Cu solder and the Ag 3 Sn particles found in the Sn-Ag-Cu solder, the Cu 6 Sn 5 particles found in both solder systems exhibited finer structure and more uniform distribution. It was noted that the thickness of the interfacial IMCs for the Sn-Co-Cu, Sn-Ag-Cu and Sn-Cu alloys was 3.5 μm, 4.3 μm and 4.1 μm, respectively, as a result of longer reflow time above the alloy's melting temperature since the Sn-Ag-Cu solder alloy has the lowest melting point. © 2006 Elsevier B.V. All rights reserved.
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| 18. |
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| 19. |
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| 20. |
- Wu, Wei-Cheng, 1979
(författare)
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Design, Processing, and Characterization of High Frequency Flip Chip Interconnects
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The demands for high frequency interconnect techniques for microwave integrated circuits (ICs) are growing with increasing operating frequencies of wireless communication systems. Interconnects have significant effect and impact on the overall system performance at high frequencies. To provide good performance in high frequency packaging, flip chip interconnect is one of the most attractive candidates compared to other schemes with low reflection and low insertion loss due to the lower parasitics involved. The widely used bond-wire interconnect suffers from serious parasitics when operating frequency reaches the gigahertz range. The tolerances such as the wire length and loop are very tight to enable an acceptable transition. At high frequencies, however, it still encounters stronger parasitics no matter how well it is controlled.This thesis deals with the design, processing, and characterization of flip chip interconnects at high frequencies. The main issues of the flip chip interconnect are described before the design criteria of the conventional flip chip interconnect are reviewed. In the following, the work of the hot-via transition is presented. It is a solution to the detuning effect of the microstrip (MS) flip chip assembly. The designs of the hot-via transition for the MS-to-CPW (coplanar waveguide) are presented; the results presented are currently world record for this technique to our knowledge. Another part of work in this thesis is the coaxial transition developed for the CPW-to-CPW flip chip interconnects. The coaxial-type transition was successfully fabricated in-house and demonstrated excellent transition performance up to 60 GHz. The entire fabrication processes for all demonstrated flip chip interconnect structures have been in-house developed and are described in details. All the design rules regarding to the different architectures for the flip chip interconnects are described and verified with the measured results. The main contributions of this thesis work are the innovative designs and the developments of both the hot-via transition and coaxial transition for the flip chip interconnects.
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