Mass concentrations of black carbon (BC) were determined in June 2006 at the top of Mount Tai (36.26° N, 117.11° E, 1534 m a.s.l.), located in the middle of Central East China, using four different ...instruments: a multi-angle absorption photometer (5012 MAAP, Thermo), a particle soot absorption photometer (PSAP, Radiance Research), an ECOC semi-continuous analyzer (Sunset Laboratory) and an Aethalometer (AE-21, Magee Scientific). High correlation coefficients (R2>0.88) were obtained between the measurements of the BC mass concentrations made using the different instruments. From the range of the slopes of the linear least-square fittings, we concluded that BC concentrations regionally-representative of the area were measured in a range with a maximum-to-minimum ratio of 1.5 (an exception was that the BC (PM2.5) concentrations derived from MAAP were ~2 times higher than the optical measurements (PM2.5) derived from the ECOC analyzer). While this range is significant, it is still sufficiently narrow to better constrain the large and highly uncertain emission rate of BC from Central East China. In detail, two optical instruments (the MAAP and the PSAP equipped with a heated inlet 400°C) tended to give higher concentrations than the thermal EC concentrations observed by the ECOC analyzer. The ratios of optical BC to thermal EC showed a positive correlation with the OC/EC ratio reported by the ECOC analyzer, suggesting two explanations. One is that the optical instruments overestimated BC concentrations in spite of careful cancellation of the scattering effect in the MAAP instrument and the expected evaporation of volatile species by heating the inlet of the PSAP instrument. The other is that the determined split points between OC and EC were too late when a large amount of OC underwent charring during the analysis, resulting in an underestimation of EC by the ECOC analyzer. High ratios of optical BC to thermal EC were recorded when the NOx/NOy ratio was low, implying the coating of the particles became thicker in an aged air mass and thus resulted in the optical instruments overestimating BC concentrations because of the lensing effect.
The purpose of this study is to conduct the critical heat flux (CHF) correlation for narrow channels. The CHF of subcooled flow boiling of water in narrow rectangular channels under atmospheric ...pressure was measured parametrically. Experimental test channels were rectangular and heated from one side with the channel gap of 0.2–3.0 mm, channel width of 7–22 mm, and heated length of 50–200 mm. First, the CHF correlation for the one-side heated rectangular channels was proposed with investigating the various system parameter effects on CHF. Next, applicability of the correlation to both-side heated rectangular channel, half-circumferentially heated tube, and full-circumferentially heated tubes was examined. New CHF correlation for narrow rectangular channels and small-diameter tubes was proposed using the critical quality, dimensionless CHF parameter and heated perimeter ratio. Calculation accuracy of the correlation is ±45% (maximum 10 times better in comparison with the existing CHF calculation methods which were proposed for the full-circumferentially heated tubes).
We investigated the electron transport property of the InGaAs/GaAs double quantum dots, the electron g factors of which are different from each other. We found that in a magnetic field, the resonant ...tunneling is suppressed even if one of the Zeeman sublevels is aligned. This is because the other misaligned Zeeman sublevels limit the total current. A finite broadening of the misaligned sublevel partially relieves this bottleneck effect, and the maximum current is reached when interdot detuning is half the Zeeman energy difference.
Previously, the authors have reported that intracellular amounts of several metabolic-related enzymes from the photosynthetic dinoflagellate Lingulodinium polyedrum(formerly Gonyaulax polyedra) ...showed a daily rhythm under a 12:12 h LD cycle. This led the authors to hypothesize that a circadian clock controls metabolism, including the tricarboxylic acid (TCA) cycle. In this study, the authors investigated daily changes in the levels of mRNA, protein, and enzyme activity of several metabolic enzymes during 12:12 h LD, 8:16 h LD, and constant light conditions. The NADP-dependent isocitrate dehydrogenase (NADPICDH) in the TCA cycle exhibited circadian changes of protein abundance and enzyme activity under all conditions, whereas its mRNA level remained constant throughout the cycle. These results indicate that the rhythm of NADPICDH is regulated by a circadian control of protein synthesis or modification rather than by message levels and suggest that the TCA cycle may be controlled by the circadian clock system.
Long‐term tropospheric nitrogen dioxide (NO2) column data obtained by the Global Ozone Monitoring Experiment (GOME) (G‐NO2) are evaluated to confirm the trends found in tropospheric NO2 abundances ...over East Asia between 1996 and 2002. For three locations in Central and East Asia, the G‐NO2 values are compared with tropospheric columns estimated from coincident observations of total NO2 by ground‐based UV/visible spectrometers and stratospheric NO2 by satellite solar occultation sensors (E‐NO2). The comparisons show a slight linear drift in G‐NO2 data from 1996 to 2002. However, it is much smaller than the standard deviation of the differences between G‐NO2 and E‐NO2 and much smaller than the increasing trends in NO2 seen by GOME over the industrial areas of China, demonstrating the validity of the trends estimated using the GOME data.
The Indian summer monsoon rainfall (ISMR), which has a strong connection to agricultural food production, has been less predictable by conventional models in recent times. Two distinct years 2002 and ...2003 with lower and higher July rainfall, respectively, are selected to help understand the natural and anthropogenic influences on ISMR. We show that heating gradients along the meridional monsoon circulation are reduced due to aerosol radiative forcing and the Indian Ocean Dipole in 2002. An increase in the dust and biomass-burning component of the aerosols through the zonal monsoon circulation resulted in reduction of cloud droplet growth in July 2002. These conditions were opposite to those in July 2003 which led to an above average ISMR. In this study, we have utilized NCEP/NCAR reanalyses for meteorological data (e.g. sea-surface temperature, horizontal winds, and precipitable water), NOAA interpolated outgoing long-wave radiation, IITM constructed all-India rainfall amounts, aerosol parameters as observed from the TOMS and MODIS satellites, and ATSR fire count maps. Based on this analysis, we suggest that monsoon rainfall prediction models should include synoptic as well as interannual variability in both atmospheric dynamics and chemical composition.
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