scholarly journals Thermochemical Mechanism of the Epoxy-Glutamic Acid Reaction with Sn-3.0 Ag-0.5 Cu Solder Powder for Electrical Joining

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 957
Author(s):  
Gwang-Mun Choi ◽  
Ki-Seok Jang ◽  
Kwang-Seong Choi ◽  
Jiho Joo ◽  
Ho-Gyeong Yun ◽  
...  
Keyword(s):  
Amino Acid ◽  
Glutamic Acid ◽  
Impact Resistance ◽  
Diglycidyl Ether ◽  
Solder Paste ◽  
Sac305 Solder ◽  
Promising Alternative ◽  
Polymeric Networks ◽  
Fine Pitch ◽  
Acid Reaction

An epoxy-based solder paste (ESP) is a promising alternative to conventional solder pastes to improve the reliability of fine-pitch electrical joining because the epoxy encapsulates the solder joint. However, development of an appropriate epoxy formulation and investigation of its reaction mechanism with solder powder is challenging. In this study, we demonstrate a newly designed ESP consisting of diglycidyl ether of bisphenol F (DGEBF) resin, Sn-3.0 Ag-0.5 Cu (SAC305) solder powder, and L-glutamic acid (Glu), which is a proteinogenic amino acid for biosynthesis of proteins in living systems. The mechanism of the thermochemical reaction was explored and tentatively proposed, which reveals that the products of the reaction between SAC305 and Glu function as catalysts for the etherification of epoxides and alcohols produced by chemical bonding between DGEBF and Glu, consequently leading to highly crosslinked polymeric networks and an enhancement of impact resistance. Our findings provide further insight into the mechanism of the reaction between various formulations comprising an epoxy, amino acid, and solder powder, and their potential use as ESPs for electrical joining.

scholarly journals Eco-Friendly Lead-Free Solder Paste Printing via Laser-Induced Forward Transfer for the Assembly of Ultra-Fine Pitch Electronic Components

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3353
Author(s):  
Marina Makrygianni ◽  
Filimon Zacharatos ◽  
Kostas Andritsos ◽  
Ioannis Theodorakos ◽  
Dimitris Reppas ◽  
...  
Keyword(s):  
High Resolution ◽  
Form Factors ◽  
Circuit Board ◽  
Lead Free ◽  
Process Conditions ◽  
Solder Paste ◽  
Electronic Components ◽  
Successful Operation ◽  
Fine Pitch ◽  
Forward Transfer

Current challenges in printed circuit board (PCB) assembly require high-resolution deposition of ultra-fine pitch components (<0.3 mm and <60 μm respectively), high throughput and compatibility with flexible substrates, which are poorly met by the conventional deposition techniques (e.g., stencil printing). Laser-Induced Forward Transfer (LIFT) constitutes an excellent alternative for assembly of electronic components: it is fully compatible with lead-free soldering materials and offers high-resolution printing of solder paste bumps (<60 μm) and throughput (up to 10,000 pads/s). In this work, the laser-process conditions which allow control over the transfer of solder paste bumps and arrays, with form factors in line with the features of fine pitch PCBs, are investigated. The study of solder paste as a function of donor/receiver gap confirmed that controllable printing of bumps containing many microparticles is feasible for a gap < 100 μm from a donor layer thickness set at 100 and 150 μm. The transfer of solder bumps with resolution < 100 μm and solder micropatterns on different substrates, including PCB and silver pads, have been achieved. Finally, the successful operation of a LED interconnected to a pin connector bonded to a laser-printed solder micro-pattern was demonstrated.

Ternary chromium(III)-nucleotide-amino acid complexes III. L-Glutamic acid derivatives

1989 ◽  
Vol 165 (1) ◽  
pp. 131-137 ◽  
Author(s):  
M. Vicens ◽  
J.J. Fiol ◽  
A. Terron ◽  
V. Moreno
Keyword(s):  
Amino Acid ◽  
Glutamic Acid ◽  
Amino Acid Complexes ◽  
Glutamic Acid Derivatives

Experimental and theoretical investigations of infrared multiple photon dissociation spectra of glutamic acid complexes with Zn2+and Cd2+

2017 ◽  
Vol 19 (19) ◽  
pp. 12394-12406 ◽  
Author(s):  
Georgia C. Boles ◽  
Cameron J. Owen ◽  
Giel Berden ◽  
Jos Oomens ◽  
P. B. Armentrout
Keyword(s):  
Amino Acid ◽  
Glutamic Acid ◽  
Infrared Multiple Photon Dissociation ◽  
Theoretical Investigations

IRMPD of [Zn(Glu-H)ACN]+was particularly interesting because fragmentation of the amino acid was favored, rather than dissociation of the ACN ligand.

scholarly journals The digestion by cattle of silage-containing diets fed at two dry matter intakes

1985 ◽  
Vol 54 (2) ◽  
pp. 483-492 ◽  
Author(s):  
H. A. Greife ◽  
J. A. Rooke ◽  
D. G. Armstrong
Keyword(s):  
Small Intestine ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Dry Matter ◽  
Soya Bean ◽  
Rumen Bacteria ◽  
Bean Meal ◽  
Soya Bean Meal

1. In a 4 x 4 Latin square experiment four cows were given, twice daily, diets consisting of (g/kg dry matter (DM)) 500 barley, 400 grass silage and 100 soya-bean meal. The diets were given at either 1.15 (L) or 2.3 (H) times maintenance energy requirements and the soya-bean meal was either untreated (U) or formaldehyde (HCH0)-treated (T).2. The passage of digesta to the duodenum was estimated using chromic oxide as a flow marker;35S was used to estimate the amount of microbial protein entering the small intestine. A microbial fraction was prepared by differential centrifugation from duodenal digesta. Samples of bacteria and of protozoa from rumen digesta were also prepared.3. The total amino acid contents of feedingstuffs, duodenal digesta, duodenal microbial material, rumen bacteria and rumen protozoa were determined by ion-exchange chromatography. The D-alanine and D-glutamic acid contents of the samples were determined by gas–liquid chromatography.4. The quantity of each amino acid entering the small intestine was significantly (P < 0,001) increased by increasing DM intake and tended to be increased by formaldehyde-treatment of the soya-bean meal. There were net losses of all amino acids across the forestomachs except for lysine, methione, o-alanine and D-glutamic acid for which there were net gains.5. There were significant (P < 0.05) differences in amino acid composition between rumen bacteria and duodenal microbial material; differences in amino acid composition between rumen bacteria and rumen protozoa were also observed.6. D-Alanine and D-glutamic acid were present in the silage but not in the barley or either of the soya-bean meals. All samples of microbes and digesta contained D-alanine and D-glutamic acid.7. The use of D-ahine and D-glUtamiC acid as markers for microbial nitrogen entering the small intestine was assessed. Estimates of the quantities of microbial N entering the small intestine based on the D-alanine or D-glutamic acid contents of rumen bacteria or duodenal microbes were significantly higher than those determined using 35S as a marker.

A Study of the Aperture Filling Process in Solder Paste Stencil Printing

1999 ◽  
Author(s):  
Jianbiao Pan ◽  
Gregory L. Tonkay
Keyword(s):  
Flip Chip ◽  
Deposition Process ◽  
Area Ratio ◽  
Solder Paste ◽  
Stencil Printing ◽  
Printing Process ◽  
Surface Mount ◽  
Fine Pitch ◽  
Main Indicator ◽  
Advanced Packaging

Abstract Stencil printing has been the dominant method of solder deposition in surface mount assembly. With the development of advanced packaging technologies such as ball grid array (BGA) and flip chip on board (FCOB), stencil printing will continue to play an important role. However, the stencil printing process is not completely understood because 52–71 percent of fine and ultra-fine pitch surface mount assembly defects are printing process related (Clouthier, 1999). This paper proposes an analytical model of the solder paste deposition process during stencil printing. The model derives the relationship between the transfer ratio and the area ratio. The area ratio is recommended as a main indicator for determining the maximum stencil thickness. This model explains two experimental phenomena. One is that increasing stencil thickness does not necessarily lead to thicker deposits. The other is that perpendicular apertures print thicker than parallel apertures.

The uptake of amino acids by mouse cells (strain LS) during growth in batch culture and chemostat culture: the influence of cell growth rate

1967 ◽  
Vol 168 (1013) ◽  
pp. 421-438 ◽  
Keyword(s):  
Amino Acids ◽  
Growth Rate ◽  
Amino Acid ◽  
Cell Growth ◽  
Glutamic Acid ◽  
Batch Culture ◽  
Amino Acid Uptake ◽  
Essential Amino Acids ◽  
Growth Yields ◽  
Acid Uptake

The uptake of thirteen essential amino acids by mouse LS cells in suspension culture was determined by bacteriological assay methods. Chemostat continuous-flow cultures were used to determine the effect of different cell growth rates on the quantitative amino acid requirements for growth. The growth yields of the cells ( Y = g cell dry weight produced/g amino acid utilized) were calculated for each of the essential amino acids. A mixture of the non-essential amino acids, serine, alanine and glycine increased the cell yield from the essential amino acids. The growth yields from nearly all the essential amino acids in batch culture were increased when glutamic acid was substituted for the glutamine in the medium. The growth yields from the amino acids in batch culture were much less at the beginning than at the end of the culture. The highest efficiencies of conversion of amino acids to cell material were obtained by chemostat culture. When glutamic acid largely replaced the glutamine in the medium the conversion of amino acid nitrogen to cell nitrogen was 100 % efficient (that is, the theoretical yield was obtained) at the optimum growth rate (cell doubling time, 43 h). The maximum population density a given amino acid mixture will support can be calculated from the data. It is concluded that in several routinely used tissue culture media the cell growth is limited by the amino acid supply. In batch culture glutamine was wasted by (1) its spontaneous decomposition to pyrrolidone carboxylic acid and ammonia, and (2) its enzymic breakdown to glutamic acid and ammonia, but also glutamine was used less efficiently than glutamic acid. Study of the influence of cell growth rate on amino acid uptake rates per unit mass of cells indicated that a marked change in amino acid metabolism occurred at a specific growth rate of 0.4 day -1 (cell doubling time, 43 h). With decrease in specific growth rate below 0.4 day -1 there was a marked stimulation of amino acid uptake rate per cell and essential amino acids were consumed increasingly for functions other than synthesis of cell material.

Interactions ofStreptomyces griseus aminopeptidase with amino acid reaction products and their implications toward a catalytic mechanism

2001 ◽  
Vol 44 (4) ◽  
pp. 490-504 ◽  
Author(s):  
R. Gilboa ◽  
A. Spungin-Bialik ◽  
G. Wohlfahrt ◽  
D. Schomburg ◽  
S. Blumberg ◽  
...  
Keyword(s):  
Amino Acid ◽  
Catalytic Mechanism ◽  
Reaction Products ◽  
Acid Reaction
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