No abstract

Blue electroluminescent diodes utilizing poly(alkylfluorene) have been demonstrated for the first time. A Schottky-type electroluminescent diode of poly(9,9-dihexylfluorene) is driven at ∼10 V and has a peak emission wavelength of 470 nm at room temperature.

A visible-light electroluminescent diode utilizing poly(3-alkylthiophene) has been demonstrated for the first time. The light emission intensity increases superlinearly with increasing injected current. Remarkable enhancement of electroluminescence intensity is obtained for a poly(3-alkylthiophene) diode with longer alkyl side chain length.

Sediment cores (MR01‐K03 PC4/PC5, 1366 m water depth) collected from off northern Japan were studied using coexisting planktonic and benthic foraminiferal radiocarbon measurements to reconstruct the history of mid‐depth circulation in the northwest Pacific. Reconstructed ventilation ages indicate that, consistent with data from a previous radiocarbon study at a shallower site, there was significant variation in mid‐depth circulation during the last deglaciation, especially in the Bølling‐Allerød (13–15 ka) and Younger Dryas (11.5–13 ka) intervals. Our record indicates that the ventilation changes in the North Pacific were antiphase to those of the North Atlantic, suggesting that atmospheric moisture transport associated with the Asian Monsoon might have played a great role in millennium‐scale ventilation changes in the North Pacific during the last deglaciation.

Millennial‐scale variability in the behavior of North Pacific Intermediate Water during the last glacial and deglacial period, and its association with Dansgaard‐Oeschger (D‐O) cycles and Heinrich events, are examined based on benthic foraminiferal oxygen and carbon isotopes (δ18Obf and δ13Cbf) and %CaCO3 using a sediment core recovered from the northeastern slope of the Bering Sea. A suite of positive δ18Obf excursions at intermediate depths of the Bering Sea, which seem at least in part associated with increases in the δ18Obf gradients between the Bering and Okhotsk Seas, suggest the Bering Sea as a proximate source of intermediate water during several severe stadial episodes in the last glacial and deglacial period. Absence of such δ18Obf gradients during periods of high surface productivity in the Bering and Okhotsk Seas, which we correlate to D‐O interstadials, suggests a reduction in intermediate water production in the Bering Sea and subsequent introduction of nutrient‐rich deep waters from the North Pacific into intermediate depths of the Bering Sea. We argue that a reorganization of atmospheric circulation in the high‐latitude North Pacific during severe cold episodes in the last glacial and deglacial period created favorable conditions for brine rejection in the northeastern Bering Sea. The resulting salinity increase in the cold surface waters could have initiated intermediate (and deep) water formation that spread out to the North Pacific.