Manufacturing practices for silicon-based power diode in fast recovery applications

This paper reports a fast recovery semiconductor diode that was developed for use in high power applications. The diode constructed in disc-type ceramic package with a peak-inverse voltage rating of 2800 V and current rating of 710 A was fabricated using float-zone (FZ) silicon wafer as the starting raw material. Alternate processes viz. gold diffusion, gamma irradiation and electron irradiation were explored for control of carrier lifetime required to tune the switching response of the diode to the desired value of 8 s. The paper compares the results of these alternate processes. The diodes were fabricated and tested for forward conduction, reverse blocking and switching characteristics. The measured values were observed to be comparable with the design requirements. The paper presents an overview of the design, manufacturing nd testing practices adopted to meet the desired diode characteristics and ratings. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2788

Control of Switching Characteristics of Silicon-based Semiconductor Diode Using High Energy Linear Accelerator

This paper reports control of switching characteristics of silicon-based semiconductor diode using electron beam produced using linear accelerator. Conventionally, p-n junction chips of diode are exposed to gamma rays from a radioactive source or electron beam from a microtron, depending upon the required level of correction. High energy linear accelerators featuring simultaneous exposure of multiple chips are recent advancements in radiation technology. The paper presents the results of the radiation process using a 10 MeV linear accelerator as applied in industrial manufacturing of a high voltage diode (2600 V). The achieved values of reverse recovery time were found to be within the design limits. The suitability of the new process was verified by constructing the trade-off curve between the switching and conduction parameters of the diode for the complete range using large number of experimental samples. The paper summarizes the advantages of the new process over the conventional methods specifically with reference to industrial requirements. The developed process has been successfully implemented in semiconductor manufacturing. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3099

Novel genetic loci associated with hippocampal volume

The hippocampal formation is a brain structure integrally involved in episodic memory, spatial navigation, cognition and stress responsiveness. Structural abnormalities in hippocampal volume and shape are found in several common neuropsychiatric disorders. To identify the genetic underpinnings of hippocampal structure here we perform a genome-wide association study (GWAS) of 33,536 individuals and discover six independent loci significantly associated with hippocampal volume, four of them novel. Of the novel loci, three lie within genes (ASTN2, DPP4 and MAST4) and one is found 200 kb upstream of SHH. A hippocampal subfield analysis shows that a locus within the MSRB3 gene shows evidence of a localized effect along the dentate gyrus, subiculum, CA1 and fissure. Further, we show that genetic variants associated with decreased hippocampal volume are also associated with increased risk for Alzheimer's disease (rg =-0.155). Our findings suggest novel biological pathways through which human genetic variation influences hippocampal volume and risk for neuropsychiatric illness

Transformation to Organic Production among the Small Tea Holders for Sustainability – Myth or Reality?

The focus of the paper is to analyze the problems and issues in transformation to organic tea production, price benefits that can be accrued, present level of organic production and farmers’ awareness and adoption using both the primary and secondary data collected from various published sources and personal interview of the sample of farmers. The sample of farmers comprises of 100 beneficiaries of Participatory Guarantee System of India (PGSIndia), four Small Tea Growers Societies, Certified Organic Tea Estate sector and three organic large tea growers including Small Tea Farmers’ Producer Company. Time series data on domestic prices, export prices for tea and organic tea, area under tea cultivation, productivity - before and after conversion were collected and analyzed. Though organic tea production is gaining momentum among the small tea growers, yield reduction after conversion is a major threat. Despite the fact that there is a yield reduction, our sample of organic tea growers were benefitted from higher remunerative price for their green tea leaves due to adoption of quality tea plucking practices with opinion that formal certification would help them to realize better prices due to market acceptance. As long as Small Tea Growers (STGs) could be able to realize premium market prices, they are ready for conversion. We also found from the soil sample analysis that there would be long term beneficial impact of organic tea cultivation on soil and productivity. Export price for organic tea is twice than that of normal tea but export share was minimal emphasizing the need for higher level of export for which formal certification is crucial since the organic tea exporters cannot source tea from uncertified STG organic farms. The awareness for certification is lacking though trainings and demonstration are being carried out by the various agencies. In this context of crisis of continuous price fall and loosing the export markets due to competitiveness, organic production is one of the alternatives among the STGs to have decent livelihood in the Nilgiris district of Tamil Nadu State of India. Creating awareness and resorting to formal certification to compete in the global market are warranted. The role of Primary Producers Societies (PPS) is critical in enforcing the quality for organic tea production and marketing

Transformation to Organic Production among the Small Tea Holders for Sustainability – Myth or Reality?

The focus of the paper is to analyze the problems and issues in transformation to organic tea production, price benefits that can be accrued, present level of organic production and farmers’ awareness and adoption using both the primary and secondary data collected from various published sources and personal interview of the sample of farmers. The sample of farmers comprises of 100 beneficiaries of Participatory Guarantee System of India (PGSIndia), four Small Tea Growers Societies, Certified Organic Tea Estate sector and three organic large tea growers including Small Tea Farmers’ Producer Company. Time series data on domestic prices, export prices for tea and organic tea, area under tea cultivation, productivity - before and after conversion were collected and analyzed. Though organic tea production is gaining momentum among the small tea growers, yield reduction after conversion is a major threat. Despite the fact that there is a yield reduction, our sample of organic tea growers were benefitted from higher remunerative price for their green tea leaves due to adoption of quality tea plucking practices with opinion that formal certification would help them to realize better prices due to market acceptance. As long as Small Tea Growers (STGs) could be able to realize premium market prices, they are ready for conversion. We also found from the soil sample analysis that there would be long term beneficial impact of organic tea cultivation on soil and productivity. Export price for organic tea is twice than that of normal tea but export share was minimal emphasizing the need for higher level of export for which formal certification is crucial since the organic tea exporters cannot source tea from uncertified STG organic farms. The awareness for certification is lacking though trainings and demonstration are being carried out by the various agencies. In this context of crisis of continuous price fall and loosing the export markets due to competitiveness, organic production is one of the alternatives among the STGs to have decent livelihood in the Nilgiris district of Tamil Nadu State of India. Creating awareness and resorting to formal certification to compete in the global market are warranted. The role of Primary Producers Societies (PPS) is critical in enforcing the quality for organic tea production and marketing

Unnatural Nucleosides with Unusual Base Pairing Properties

Synthetic modified nucleosides designed to pair in unusual ways with natural nucleobases have many potential applications in nucleic acid biochemistry. This overview lays the foundation for future protocol units on synthesis and application of unnatural bases, with particular emphasis on unnatural base analogs that mimic natural bases in size, shape, and biochemical processing. Topics covered including base pairs with alternative H‐bonding schemes, hydrophobic base pairs, degenerate bases, universal nucleosides, and triplex constituents.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152854/1/cpnc0104.pd