The census of exoplanets is incomplete for orbital distances larger than 1 AU. Here, we present 41long-period planet candidates in 38systems identified by Planet Hunters based on Kepler archival data (Q0-Q17). Among them, 17exhibit only one transit, 14have two visible transits, and 10have more than three visible transits. For planet candidates with only one visible transit, we estimate their orbital periods based on transit duration and host star properties. The majority of the planet candidates in this work (75%) have orbital periods that correspond to distances of 1-3 AU from their host stars. We conduct follow-up imaging and spectroscopic observations to validate and characterize planet host stars. In total, we obtain adaptive optics images for 33stars to search for possible blending sources. Six stars have stellar companions within 4″. We obtain high-resolution spectra for 6stars to determine their physical properties. Stellar properties for other stars are obtained from the NASA Exoplanet Archive and the Kepler Stellar Catalog by Huber et al. We validate 7 planet candidates that have planet confidence over 0.997 (3σ level). These validated planets include 3 single-transit planets (KIC-3558849b, KIC5951458b, and KIC-8540376c), 3 planets with double transits (KIC-8540376b, KIC-9663113b, and KIC10525077b), and 1 planet with four transits (KIC-5437945b). This work provides assessment regarding the existence of planets at wide separations and the associated false positive rate for transiting observation (17%-33%). More than half of the long-period planets with at least three transits in this paper exhibit transit timing variations up to 41 hr, which suggest additional components that dynamically interact with the transiting planet candidates. The nature of these components can be determined by follow-up radial velocity and transit observations.

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Gate leakage that occurs in deep-submicrometer CMOS might be a convenient new way of implementing highly resistive elements with minimal area consumption. We present an adaptive device that exploits gate leakage in the 90-nm STM CMOS process for offset cancellation at its input. This is achieved by a high-pass-filtering input stage with a very low cutoff due to a time constant of approximately 130 ms. In this filter, three 0.1 0.22 m 2 gate-oxide structures are used to achieve the equivalent of a 6.5-G resistance.