Anomalous geomagnetic variations and possible causative structures along foothills of Himachal Pradesh-Kumaun-Himalaya

This paper presents the results of a magnetometer array study covering Kangra region to supplement information already available on the nature of geoelectrical structure at the foothills of Himachal Pradesh-Kumaun-Himalaya. The observed induction pattern across the Himalayan frontal fault is found to be the expression of a psuedo-geomagnetic coast effect associated with the edge of sheet current flowing in the sediments of the Indo Gangetic Plains. An additional conductive sheet that is required beneath the frontal folded belt may represent increased hydration of certain sedimentary layers

Experimental study of a SINIS detector response time at 350 GHz signal frequency

Response time constant of a SINIS bolometer integrated in an annular ring antenna was measured at a bath temperature of 100 mK. Samples comprising superconducting aluminium electrodes and normal-metal Al/Fe strip connected to electrodes via tunnel junctions were fabricated on oxidized Si substrate using shadow evaporation. The bolometer was illuminated by a fast black-body radiation source through a band-pass filter centered at 350 GHz with a passband of 7 GHz. Radiation source is a thin NiCr film on sapphire substrate. For rectangular 10\uf7100 μs current pulse the radiation front edge was rather sharp due to low thermal capacitance of NiCr film and low thermal conductivity of substrate at temperatures in the range 1-4 K. The rise time of the response was ∼1-10 μs. This time presumably is limited by technical reasons: high dynamic resistance of series array of bolometers and capacitance of a long twisted pair wiring from SINIS bolometer to a room-Temperature amplifier

Reflection-enhanced gain in traveling-wave parametric amplifiers

The operating principle of traveling-wave parametric amplifiers is typically understood in terms of the standard coupled mode theory, which describes the evolution of forward propagating waves without any reflections, i.e., for perfect impedance matching. However, in practice, superconducting microwave amplifiers are unmatched nonlinear finite-length devices, where the reflecting waves undergo complex parametric processes, not described by the standard coupled mode theory. Here, we present an analytical solution for the TWPA gain, which includes the interaction of reflected waves. These reflections result in corrections to the well-known results of the standard coupled mode theory, which are obtained for both three-wave and four-wave mixing processes. Due to these reflections, the gain is enhanced and unwanted nonlinear phase modulations are suppressed. Predictions of the model are experimentally demonstrated on two types of unmatched TWPA, based on coplanar waveguides with a central wire consisting of (i) a high kinetic inductance superconductor, and (ii) an array of 2000 Josephson junctions

Antimicrobial Activity and HPLC Fingerprinting of Crude Ocimum Extracts

The antimicrobial activity of crude methanolic and aqueous extracts of Ocimum sanctum and Ocimum kilimandsacharicum against gram positive, gram negative and antifungal activity was evaluated to find the zone of inhibition and to set a HPLC profile or fingerprint of these extracts. The crude methanolic extract of Ocimum sanctum showed strong antimicrobial activity against S.aureus and C. albicans and moderate activity against E. coli and B. subtilis. The crude methanolic extract of Ocimum kilimandsacharicum showed strong antimicrobial activity against S. aureus, E. coli and C. albicans at higher concentration, same as that shown by the standard for C. albicans. It showed moderate activity against B. subtilis. The crude aqueous extracts of Ocimum sanctum showed strong antimicrobial activity against S.aureus and moderate against others. Whereas the crude aqueous extracts of Ocimum kilimandsacharicum showed moderate activity against the gram positive and gram negative organisms and strong activity against C. albicans at higher concentration, same as that shown by the standard for C. albicans

Anomalies in geomagnetic variations on peninsular India near Palk Strait

Anomalies in transient geomagnetic variations have been previously studied using data from five permanent observatories in the peninsular India. The results from the three observatories falling under the equatorial electrojet showed the presence of a strong current concentration between India and Sri Lanka Island. The currents seem to flow at the depth of the crust or upper mantle. These findings have been confirmed hereby by collecting data from an array of magnetometers. We associate the channelling to the presence of a geological conductor between India and Sri Lanka Island

Induction anomalies in geomagnetic Sq in peninsular India

Anomalies in geomagnetic Sq(H), Sq(Z) and Sq(D), as recorded at an array of 21 magnetometers and 5 permanent observatories in peninsular India during 1979-1980, are analyzed and discussed in relation to geology. Signatures of the Kodaikanal batholith, the Dharwar series of rocks and a graben structure in the Palk Strait on the geomagnetic records of nearby stations are unmistakably identified and associated with internal induction effect. The extent and influence of the ionospheric equatorial electrojet and oceanic induced currents observed on the ground in this complex region are also mapped

Electrical and optical properties of a bolometer with a suspended absorber and tunneling-current thermometers

We have developed a bolometer with a suspended normal-metal absorber connected to superconducting leads via tunneling barriers. Such an absorber has reduced heat losses to the substrate, which greatly increases the responsivity of the bolometer to over 109 V/W at 75 mK when measured by dc Joule heating of the absorber. For high-frequency experiments, the bolometers have been integrated in planar twin-slot and log-periodic antennas. At 300 GHz and 100 mK, the bolometer demonstrates the voltage and current response of 3 × 108 V/W and 1.1 × 104 A/W, respectively, corresponding to the quantum efficiency of ∼15 electrons per photon. An effective thermalization of electrons in the absorber favors the high quantum efficiency. We also report on how the in-plane- and transverse magnetic fields influence the device characteristics

Electrical and optical properties of a bolometer with a suspended absorber and tunneling-current thermometers

We have developed a bolometer with a suspended normal-metal absorber connected to superconducting leads via tunneling barriers. Such an absorber has reduced heat losses to the substrate, which greatly increases the responsivity of the bolometer to over 109 V/W at 75 mK when measured by dc Joule heating of the absorber. For high-frequency experiments, the bolometers have been integrated in planar twin-slot and log-periodic antennas. At 300 GHz and 100 mK, the bolometer demonstrates the voltage and current response of 3 × 108 V/W and 1.1 × 104 A/W, respectively, corresponding to the quantum efficiency of ∼15 electrons per photon. An effective thermalization of electrons in the absorber favors the high quantum efficiency. We also report on how the in-plane- and transverse magnetic fields influence the device characteristics

MKID digital readout tuning with deep learning

Microwave Kinetic Inductance Detector (MKID) devices offer inherent spectral resolution, simultaneous read out of thousands of pixels, and photon-limited sensitivity at optical wavelengths. Before taking observations the readout power and frequency of each pixel must be individually tuned, and if the equilibrium state of the pixels change, then the readout must be retuned. This process has previously been performed through manual inspection, and typically takes one hour per 500 resonators (20 h for a ten-kilo-pixel array). We present an algorithm based on a deep convolution neural network (CNN) architecture to determine the optimal bias power for each resonator. The bias point classifications from this CNN model, and those from alternative automated methods, are compared to those from human decisions, and the accuracy of each method is assessed. On a test feed-line dataset, the CNN achieves an accuracy of 90% within 1 dB of the designated optimal value, which is equivalent accuracy to a randomly selected human operator, and superior to the highest scoring alternative automated method by 10%. On a full ten-kilopixel array, the CNN performs the characterization in a matter of minutes — paving the way for future mega-pixel MKID arrays