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- 저자 : S. Jayesh (검색결과 5 건)
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S. Jayesh,Jacob Elias 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.1
Lead cannot be used in the solder material anymore due to environmental legislations which is related to the inherent toxicityof lead. This paper investigates the effect of silver (Ag) addition on the melting behavior, microstructure, and microhardnessof Ternary lead free solder alloy Sn–0.5Cu–3Bi. The contact angle between Sn–0.5Cu–3Bi and Cu-substrate were alsoanalyzed. Samples with different Ag percentages (0, 0.25, 0.5, 0.75 and 1.0 wt%) in Sn–0.5Cu–3Bi were prepared using aninduction furnace, annealing furnace with argon gas. Tests were conducted for melting temperature using TG–DTA analysis,chemical composition using ICP–OES, Hardness using Vickers’s hardness tester and the microstructure using Field emissionscanning electron microscopy. The obtained results were thoroughly analyzed. The results show that the Ag addition hasstriking positive effects on enhancing the properties of the base solder alloy. Melting point is found to be decreasing withthe increase in Ag content. Hardness and contact angle were improved with the addition of Ag. The microstructure observationsrevealed that the Ag was uniformly distributed on the surface of the solder matrix. The recommended content of theAg to be added into the Sn–0.5Cu–3Bi solder alloy is 1.0 wt%. With the observed better properties it can be considered asthe potential alternative to lead–tin alloy.
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S. Jayesh,Jacob Elias 한국전기전자재료학회 2020 Transactions on Electrical and Electronic Material Vol.21 No.2
Lead is banned in alloy making citing toxicity concerns and environmental legislations. Researchers around the world were in search of new lead free solder alloys which could replace the old Sn–Pb alloy. Solder alloys are important electronic material used in electronics package industries. In this study, shear strength and impact toughness tests were conducted on Sn–0.5Cu–3Bi when different amounts of Ag (0.25, 0.5, 0.75, 1 wt%) is added. Shear strength test is done using micro force test system. Impact toughness test is done using Charpy impact test set up by fi nding the energy diff erence before and after impact. Ultimate shear stress is found to be increased from 17.3 to 23 MPa. Yield strength is found to be increased from 23.4 to 28 MPa. Impact toughness of the alloys increased from 10.4 to 11.3 J. EDAX analysis and mapping of the Sn–0.5Cu–3Bi–1Ag is also obtained Sn–0.5Cu–3Bi–1Ag is found to be having good improved shear strength and impact toughness than Sn–0.5Cu–3Bi.
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S. Jayesh,Jacob Elias 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.2
Various environment legislations lead to the ban of Pb in solder alloy making. Solder alloy is an integral part of electronic packaging industry. As a result of this researchers were searching for new combinations without lead which can replace Sn–Pb solder alloy. The new lead free solder joint should possess good mechanical properties, good wetting properties and good corrosion resistance properties. Many lead free solder alloys were discovered. Sn–0.5Cu–3Bi is a good candidate for replacing the Sn–Pb alloy with good properties. The addition of Ag into the alloy enhanced the properties, especially 1% by wt. Ag. In this paper, investigations on the corrosion behavior of Sn–0.5Cu–3Bi–xAg (x = 0, 0.5, 1% by wt.) in 3.5% NaCl is carried out using weight loss method. Microstructure and EDAX analysis were also conducted in the analysis. It is found that the corrosion rate is minimum with 1% by wt. addition of Ag. Corrosion rate is less when compared with the SAC (Sn–Ag–Cu). Sn–0.5Cu–3Bi–1Ag can be considered as a potential lead free solder joint with good corrosion resistance.
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Swamikannu, Bhuminathan,Kumar, Kishore S.,Jayesh, Raghavendra S.,Rajendran, Senthilnathan,Muthupalani, Rajendran Shanmugam,Ramanathan, Arvind Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.5
Background: Dilantin sodium (phenytoin) is an antiepileptic drug, which is routinely used to control generalized tonic clonic seizure and partial seizure episodes. A few case reports of oral squamous cell carcinomas arising from regions of phenytoin induced gingival overgrowth (GO), and overexpression of mitogenic factors and p53 have presented this condition as a pathology with potential to transform into malignancy. We recently investigated the genetic status of p53 and H-ras, which are known to be frequently mutated in Indian oral carcinomas in GO tissues and found them to only contain wild type sequences, which suggested a non-neoplastic nature of phenytoin induced GO. However, besides p53 and H-ras, other oncogenes and tumor suppressors such as PIK3CA, p14ARF, p16INK4a and $p21^{Waf1/Cip1}$, are frequently altered in oral squamous cell carcinoma, and hence are required to be analyzed in phenytoin induced GO tissues to be affirmative of its non-neoplastic nature. Methods: 100ng of chromosomal DNA isolated from twenty gingival overgrowth tissues were amplified with primers for exons 9 and 20 of PIK3CA, exons $1{\alpha}$, $1{\beta}$ and 2 of p16INK4a and p14ARF, and exon 2 of $p21^{Waf1/Cip1}$, in independent reactions. PCR amplicons were subsequently gel purified and eluted products were sequenced. Results: Sequencing analysis of the twenty samples of phenytoin induced gingival growth showed no mutations in the analyzed exons of PIK3CA, p14ARF, p16INK4a and $p21^{Waf1/Cip1}$. Conclusion: The present data indicate that the mutational alterations of genes, PIK3CA, p14ARF, p16INK4a and $p21^{Waf1/Cip1}$ that are frequently mutated in oral squamous cell carcinomas are rare in phenytoin induced gingival growth. Thus the findings provide further evidence that phenytoin induced gingival overgrowth as a non-neoplastic lesion, which may be considered as clinically significant given the fact that the epileptic patients are routinely administered with phenytoin for the rest of their lives to control seizure episodes.
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Siddhartha Das,Sandeep Gurav,Vivek Soni,Arvind Ingle,Bhabani S. Mohanty,Pradip Chaudhari,Kiran Bendale,Kanchan Dholam,Jayesh R. Bellare 한국조직공학과 재생의학회 2018 조직공학과 재생의학 Vol.15 No.2
A titanium implant surface when coated with biodegradable, highly porous, osteogenic nanofibrous coating has shown enhanced intrinsic osteoinductive and osteoconductive properties. This coating mimics extracellular matrix resulting in differentiation of stem cells present in the peri-implant niche to osteoblast and hence results in enhanced osseointegration of the implant. The osteogenic nanofibrous coating (ONFC) consists of poly-caprolactone, gelatin, nano- sized hydroxyapatite, dexamethasone, ascorbic acid and beta-glycerophosphate. ONFC exhibits optimum mechanical properties to support mesenchymal stem cells and steer their osteogenic differentiation. ONFC was subjected to various characterization tests like scanning electron microscopy, Fourier-transform infrared spectroscopy, x-ray diffractometry, thermal degradation, biomineralization, mechanical properties, wettability and proliferation assay. In pre-clinical animal trials, the coated implant showed enhanced new bone formation when placed in the tibia of rabbit. This novel approach toward implant bone integration holds significant promise for its easy and economical coating thus marking the beginning of new era of electrospun osteogenic nanofibrous coated bone implants.
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