in this study, caffeic acid (ca) and its three derivatives including 3-caffeoylquinic acid (3-cqa, neochlorogenic acid), 4-caffeoylquinic acid (4-cqa, cryptochlorogenic acid), and 5-caffeoylquinic acid (5-cqa, chlorogenic acid) were identified in bupleurum chinense aerial parts using reverse-phase high-performance liquid chromatography (rp-hplc) with photodiode array (pda) detector, reference c...

A very Jow noise measurement system is described with a noise temperature of 0.5 K consisting of a mercury wetted reed switch, low noise preamplifier, and synchronous detector. The set-up can te tuned from 20 kHz up to 3.15 GHz corresponding to the bandwidth of relay and prcamplifieI'. The shot noise of CdSjCulnSe2-photodiode,s has been investigated. Deviations from the expected behaviour indic...

We report operation and characterization of a lab-assembled single-photon detector based on commercial silicon avalanche photodiodes (PerkinElmer C30902SH, C30921SH). Dark count rate as low as 5 Hz was achieved by cooling the photodiodes down to -80 °C. While afterpulsing increased as the photodiode temperature was decreased, total afterpulse probability did not become significant due to detect...

We demonstrated a laser ranging system with single photon detection at 1550 nm. The single-photon detector was a 1-GHz sine-wave gated InGaAs/InP avalanche photodiode. In daylight, 8-cm depth resolution was achieved directly by using a time-of-flight approach based on time-correlated single photon counting measurement. This system presented a potential for low energy level and eye-safe laser ra...

Silicon photodiode pyranometers have been studied extensively for application in solar energy resource assessment instruments. An example is the LI-COR, Inc. 200SZ detector that is used in rotating shadowband radiometers. While excellent results have been achieved LI-COR, Inc. calibration methods are not fully disclosed and LI-COR’s stated +/5% accuracy is less than desirable. This research aim...

The strawberry cultivars Arosa, Clery, Miss, Raurica, Queen Elisa, Diamante and Madeleine grown in Slovenia were harvested at the commercially maturity stage and the content of total ascorbic acid and dehydroascorbic acid (DHA) was determined. Ascorbic acid (AA) was measured by using high-performance liquid chromatography and photodiode array detector. The total AA content of cultivars ranged f...

A 106-cm long, nearly confocal cavity with high reflectivity mirrors (R >99.9% at 355 nm, r = 100 cm) was used for the cavity ring down spectrometer. Probe laser radiation was passed through one of the mirrors into the cavity. The probe radiation was generated by spatially filtering the frequency doubled fundamental output from a dye laser. Spatial filtering used a pinhole and lens assembly. A ...

The background to this work was a prototype shadow sensor, which was designed for retro-fitting to an advanced LIGO (Laser Interferometer Gravitational wave Observatory) test-mass/mirror suspension, in which a 40 kg test-mass/mirror is suspended by four approximately 600 mm long by 0.4 mm diameter fused-silica suspension fibres. The shadow sensor comprised a LED source of Near InfraRed (NIR) ra...