Scaling NbTiN-based ac-powered Josephson digital to 400M devices/cm2^2

We describe a fabrication stackup for digital logic with 16 superconducting NbTiN layers, self-shunted a-silicon barrier Josephson Junctions (JJs), and low loss, high-$\kappa$ tunable HZO capacitors. The stack enables 400 MJJ/cm$^2$ device density, efficient routing, and AC power distribution on a resonant network. The materials scale beyond 28nm lithography and are compatible with standard high-temperature CMOS processes. We report initial results for two-metal layer NbTiN wires with 50nm critical dimension. A semi-ascendance wire-and-via process module using 193i lithography and 50nm critical dimension has shown cross-section uniformity of 1%=1s across the 300mm wafer, critical temperature of 12.5K, and critical current of 0.1mA at 4.2K. We also present a new design of the resonant AC power network enabled by NbTiN wires and HZO MIM capacitors. The design matches the device density and provides a 30 GHz clock with estimated efficiency of up to 90%. Finally, magnetic imaging of patterned NbTiN ground planes shows low intrinsic defectivity and consistent trapping of vorteces in 0.5 mm holes spaced on a 20 $\mu$m x 20 $\mu$m grid.Comment: 7 pages, 3 figure

Adoption status of improved production technology in rice cultivation in Kanchanpur, Nepal

A study was carried out in 2020 to assess the scenario of the improved production technologies among rice growers in Kanchanpur and to identify the factors influencing the adoption of these technologies. The simple random sampling procedure was used to collect data from 90 respondents using a semi-structured interview schedule from Belauri, Bhimdutta municipality, and Beldandi rural municipality which are under the command area of the rice super zone, Kanchanpur. The information on prevailing cultural practice, production, and productivity, adoption of improved technology, problems/constraints faced by farmers in rice cultivation in the study area were collected from the farmers by interview. The data were processed, cleaned, and analyzed using software MS-excel and SPSS. The simple descriptive and inferential statistics like chi-square and binary logistic regression models were used to find the relationship between dependent and independent variables. Respondents adopted plant protection measures (chemical weed control, insects, and disease control) and seed treatment relatively less than they adopted recommended variety, Seed Replacement Rate (SRR), and storage treatment.  The majority of the respondents were affiliated with the farmers’ groups but the majority of them had not received training. Furthermore, spade, hoe, tractor, thresher, sickle, wooden plough bullock cart water pumps, tillers, reapers were used by respondents. Binary logistic regression revealed that membership of agriculture group, advice from agriculture technician, training, visit of extension workers and rice cultivated land had a positive and significant effect on the adoption of various production practices. Inadequate availability of fertilizers and inputs (0.85), Inadequate training (0.68), inadequate machinery availability (0.54) were the major constraints faced by the farmers on rice cultivation

Investigations of antioxidant and antibacterial activity of leaf extracts of Azadirachta indica

Active ingredients of medicinal plants have been used to cure several human diseases. Azadirachta indica is one of the most versatile medicinal plants having a wide spectrum of biological activity due to the presence of large number of bioactive compounds. The present study was conducted to evaluate antimicrobial and antioxidant efficiency and phytochemical screening of A. indica leaf extract using methanol as a solvent. A qualitative phytochemical screening was performed for the detection of various phytochemicals. Then, the quantitative determination of total phenols, flavonoids and proanthocyanidins was done and expressed in terms of gallic acid and rutin equivalent. Total phenolic, flavonoid and proanthocyanidin content were found to be 85.9±4.0, 104.9±5.5 and 65.4±13.9 mg/g of plant extract, respectively. Also, the antibacterial activity was performed using six different bacterial strains: Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Salmonella typhi (ATCC 14028), Klebsiella pneumoniae (ATCC 700603), Pseudomonas aeruginosa (ATCC 27853) and Proteus vulgaris (ATCC 35659). It was found that the maximum zone of inhibition of 22±3 mm was shown against S. aureus using 700 μg plant extract. Similarly, the antioxidant activity of the methanolic extract of plant was also determined and it was found that maximum inhibition obtained was 71.23% when 500 μg plants extract was used.Key words: Azadirachta indica, methanol, antibacterial, antioxidant

Vapor Phase Conversion Synthesis of Higher Manganese Silicide (MnSi_1.75) Nanowire Arrays for Thermoelectric Applications

If nanostructured thermoelectric materials are to be used for future energy harvesting and power generation applications, scalable production of thermoelectric nanostructures must be developed. Herein we report a vapor phase conversion method to synthesize nanowire (NW) arrays of semiconducting higher manganese silicides (HMS, or MnSi_1.75) for enhanced thermoelectric applications. Dense arrays of silicon NWs obtained by metal-assisted chemical etching were converted to single-crystalline HMS NW arrays with the original nanoscale morphology preserved by reacting with Mn vapor in a sealed stainless steel reactor at 950 °C. Structural characterization by X-ray and electron diffraction and high-resolution transmission electron microscopy confirm that the converted NWs are single-crystalline NWs of HMS phases such as Mn₇Si₁₂, Mn₂₇Si₄₇, and Mn₃₉Si₆₈. Investigations of the conversion process using <i>in situ</i> high resolution powder X-ray diffraction (HRPXRD) and mechanistic experiments reveal that the presence of excess Si substrate underneath the Si NWs, careful control of Mn precursor, and high reaction temperature are crucial to the selective formation of HMS phase. The electrical resistivity of these HMS NWs are similar to that of the bulk HMS

Thermoelectric Properties of Undoped High Purity Higher Manganese Silicides Grown by Chemical Vapor Transport

Semiconducting higher manganese silicides (HMS), with a nominal composition of MnSi_1.73, are particularly promising thermoelectric materials because of their elemental abundance, nontoxicity, and reported ZT of around 0.4 at 800 K for undoped samples. However, embedded MnSi impurities naturally form during the melt growth of HMS materials. The influences of such naturally occurring MnSi impurities within bulk HMS have yet to be carefully studied. Herein, we report the synthesis of high-purity MnSi-free single crystals of HMS by chemical vapor transport and the thermoelectric properties of consolidated HMS samples prepared by spark plasma sintering (SPS). The high purity of the HMS crystals is verified by scanning and transmission electron microscopy, electron diffraction, and synchrotron high-resolution X-ray diffraction. Despite successfully growing high purity HMS single crystals, we find that MnSi will nevertheless precipitate from HMS after SPS processing. In-situ sychrotron high-resolution X-ray diffraction experiments show that HMS are unstable at high temperatures. Despite the precipitation of MnSi inclusions within the HMS materials, we show that samples prepared from undoped single crystals of HMS exhibit higher hole mobilities owing to their higher purity, resulting in an improved maximum ZT of 0.52 ± 0.08 at 750 K