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[en] Scaling laws for optimized HCN lasers have been deduced and experimentally verified. Following these laws, two lasers of particular interest have been built and used as light sources for density profile measurements of a Tokamak plasma
[fr]Des lois d'echelles ont ete etablies et verifiees experimentalement pour des lasers HCN optimises. Deux lasers particulierement interessants ont ete construits suivant ces lois et utilises comme sources lumineuses pour des mesures de profil de densite dans un plasma Tokamak
[en] We analyze the HCO+ 3-2 and H13CO+ 3-2 line profiles of 27 high-mass star-forming regions to identify asymmetries that are suggestive of mass inflow. Three quantitative measures of line asymmetry are used to indicate whether a line profile is blue, red, or neither-the ratio of the temperature of the blue and red peaks, the line skew, and the dimensionless parameter δv. We find nine HCO+ 3-2 line profiles with a significant blue asymmetry and four with significant red asymmetric profiles. Comparing our HCO+ 3-2 results to HCN 3-2 observations from Wu et al., we find that eight of the blue and three of the red have profiles with the same asymmetry in HCN. The eight sources with blue asymmetries in both tracers are considered strong candidates for inflow. Quantitative measures of the asymmetry (e.g., δv) tend to be larger for HCN. This, combined with possible HCO+ abundance enhancements in outflows, suggests that HCN may be a better tracer of inflow. Understanding the behavior of common molecular tracers like HCO+ in clumps of different masses is important for properly analyzing the line profiles seen in a sample of sources representing a broad range of clump masses. Such studies will soon be possible with the large number of sources with possible self-absorption seen in spectroscopic follow-up observations of clumps identified in the Bolocam Galactic Plane Survey.
[en] We have investigated the presence of dense gas toward the radio source Cen A by looking at the absorption of the HCO+ and HCN (3-2) lines in front of the bright continuum source with the Submillimeter Array. We detect narrow HCO+ (3-2) absorption, and tentatively HCN (3-2), close to the systemic velocity. For both molecules, the J = 3 - 2 absorption is much weaker than for the J = 1 - 0 line. From simple excitation analysis, we conclude that the gas density is of the order of a few 104 cm-3 for a column density N(HCO+)/ΔV of 3 x 1012 cm-2 km-1 s and a kinetic temperature of 10 K. In particular, we find no evidence for molecular gas density higher than a few 104 cm-3 on the line of sight to the continuum source. We discuss the implications of our finding on the nature of the molecular gas responsible for the absorption toward Cen A.
[en] In this paper, three unregulated components, ammonia, nitrous oxide and hydrogen cyanide, emitted from five passenger vehicles are investigated. With focus upon emission factors from existing production technology, vehicles produced between 1989 and 1998 with considerable mileage (7000 to 280,000) are chosen. Among the five vehicles, four were sold in the European market, whereas one was sold in the US market. The vehicles are tested on a chassis dynamometer. An EU2000 Driving Cycle (NEDC) and a US Urban Driving Cycle (UDC) of the Federal Test Procedure 75 (FTP-75) are used in the study. The regulated emissions are measured using a Horiba Mexa series. Unregulated emissions, ammonia (NH3), nitrous oxide (N2O) and hydrogen cyanide (HCN) are analysed by mass spectrometer, gas chromatography and CNT-NA, TIM315-74W method, respectively. Both the unregulated emissions and the regulated emissions show driving cycle dependency; and they are also improved with newer vehicle and emission control technology. However, a gasoline direct injection vehicle (relatively new technology in this study) has rather high regulated emissions, whereas the NH3, N2O and HCN emissions are low
[en] We report new results on outflow and infall in the star-forming cores W3-SE SMA-1 and SMA-2 based on analysis of ∼2.''5 resolution observations of the molecular lines HCN(3-2), HCO+(3-2), N2H+(3-2), and CH3OH(52,3-41,3) with the Submillimeter Array (SMA). A high-velocity bipolar outflow originating from the protostellar core SMA-1 was observed in the HCN(3-2) line, with a projected outflow axis at a position angle of 480. The detection of the outflow is confirmed from other molecular lines. An inverse P-Cygni profile in the HCN(3-2) line toward SMA-1 suggests that at least one of the double cores accretes matter from the molecular core. A filamentary structure in the molecular gas surrounds SMA-1 and SMA-2. Based on the SMA observations, our analysis suggests that the double pre-stellar cores SMA-1 and SMA-2 result from fragmentation in the collapsing massive molecular core W3-SE, and it is likely that they are forming intermediate- to high-mass stars which will be new members of a star cluster in the W3-SE region.
[en] Introduction: One of the major concerns regarding a mass disaster is to clarify the involved class of toxicant. Hydrocyanic acid and its derivatives are considered a likelihood threat. However, cyanide-induced signs and symptoms are described as nonspecific, precluding any characterization at the scene. Chemical disaster may result in the exposure, at the same time, of a large number of casualties. In such a condition, not only the nature of signs and symptoms (qualitative knowledge), but also their frequency and magnitude of occurrence (quantitative knowledge) would be of value for a presumptive diagnosis. Therefore, we attempted at quantifying signs and symptoms of cyanide poisoning at the time of presentation in order to improve its recognition and, therefore, the rapidity of antidote supply. Methods: cases of pure cyanide poisoning published in the medical literature and on which the authors consulted were reviewed. Smoke inhalations were excluded. Clinical data were collected before any antidotal treatment except for oxygen. Results are expressed as percentage or median [extremes] Results: Data on 149 acute pure cyanide poisonings described since 1950 were extracted and summarized. Cyanide poisonings primarily resulted from suicide attempts by ingestion. Median time between exposure and onset of symptoms was 30 minutes (1-1140). An abnormal odour was looked for in only 24 out of the 149 cases and was reported in 16 cases (67%). Acute cyanide poisoning was characterized by abnormal neurological status (82%) including coma (66%), dilated pupils (78%), and abnormal respiratory pattern (93%) including hyperpnoea, polypnea, and bradypnea. Muscular tone was nonspecific. Seizures were witnessed in only 26% of poisonings, premature ventricular contractions in 16%, and pulmonary edema in 5%. Median heart rate was 95 bpm [0-176], and median systolic blood pressure was 90 mmHg [0-168]. Arterial pH was 7.20 [6.40-7.60], PaCO2 was 25.2 mmHg [9-53.6], and plasma lactate was 13.4 mmol/l [2.4-53].The mortality rate was 28%. Median blood cyanide concentration was 4.2 mg/l [0.1-42.5]. Conclusion: easily collected signs at the scene by an emergency medical service are useful in recognizing cyanide poisoning allowing deciding prompt supply in antidote to cyanide.(author)
[en] Rate constants obtained by the ICR technique are reported for reaction (1), C2H2+ + HCN and reaction (2) HCN+ + C2H2 such that k1 = 3.6 x 10-10 and k2 = 6.9 x 10-10 cm3 molecule-1 s-1, respectively. Differences between these results and other measurements of reaction (1) are discussed. The relevance of reaction (1) to the formation of HC3N in interstellar clouds is also briefly assessed. (Auth.)