Volatile-rich lunar soil: evidence of possible cometary impact

A subsurface Apollo 16 soil, 61221, is much richer in volatile compounds than soils from any other locations or sites as shown by thermal analysis-gas release measurements. A weight loss of 0.03 percent during the interval 175 degrees to 350 degrees C was associated with the release of water, carbon dioxide, methane, hydrogen cyanide, hydrogen, and minor amounts of hydrocarbons and other species. These volatile components may have been brought to this site by a comet, which may have formed North Ray crater.     

Apollo lunar module engine exhaust products

Organic combustion products generated by the lunar module descent engine, which burns a 1:1 mixture of unsymmetrical dimethylhydrazine fuel and nitrogen tetroxide oxidizer, have been analyzed. The major gaseous combustion products found were ammonia, water, carbon monoxide, nitrous oxide, oxygen, carbon dioxide, and nitric oxide. The minor products were acetylene, hydrogen cyanide, ethylene, formaldehyde, propadiene, ketene, cyanous acid, hydrazoic acid, various methylamines, acetaldehyde, methyl nitrite, formic acid, nitrous acid, butadiyne, nitrilohydrazines, nitromethane, and nitrosohydrazines with other oxidized derivatives of unsymmetrical dimethylhydrazine and hydrazine. The ion intensities of the various species in all mass spectra were estimated as the following concentrations: the gases (NH(3), H(2)O, CO, NO, O(2), CO(2), and NO(2)), 87.7 percent; compounds of C, H, and O, 6.0 percent; and compounds of C, H, and N (with traces of O), 5.8 percent.     

Hydrogen Cyanide Production During Reduction of Nitric Oxide over Platinum Catalysts: Transient Effects

The formation of hydrogen cyanide during the catalytic reduction of nitric oxide (NO) with carbon monoxide and hydrogen was studied with a bench-scale flow reactor. The previously reported inhibition by sulfur dioxide of the formation of hydrogen cyanide was found to be counteracted by transient admission of oxygen to the catalyst. These results are discussed in the context of the control of automotive emissions of NO and the prevention of hydrogen cyanide production during such control.     

滤棒成型参数对卷烟七种烟气有害成分释放量的影响

为明确不同滤棒成型参数对卷烟7种烟气有害成分(一氧化碳、氰化氢、亚硝胺、氨、苯并芘、苯酚及巴豆醛)释放量的影响规律,采用正交试验设计方法研究了卷烟滤棒成型材料中丝束规格、丝束填充量、三乙酸甘油酯添加量3个参数对卷烟7种烟气有害成分释放量的影响。通过直观分析和极差分析,结果表明,滤棒丝束规格是影响7种烟气有害成分释放量中巴豆醛、苯并芘、苯酚、氰化氢和亚硝胺的第一重要因素,是一氧化碳和氨的第二重要因素;丝束填充量是影响7种烟气有害成分释放量中一氧化碳、苯酚、苯并芘和亚硝胺的第二影响要素;三乙酸甘油酯添加量是影响7种烟气有害成分释放量中氰化氢和氨的第一影响要素,是巴豆醛的第二影响要素。     

卷烟纸对卷烟主流烟气中氢氰酸的影响

[目的]探讨卷烟纸特性对卷烟主流烟气中氢氰酸的影响。[方法]采用不同特性的卷烟纸卷制卷烟,通过连续流动分析仪测定其主流烟气中氢氰酸的含量。[结果]卷烟纸助燃剂含量、透气度和亚麻配比对卷烟主流烟气中氢氰酸的影响具有显著的线性规律;卷烟纸克重、卷烟纸助燃剂类型对卷烟主流烟气中氢氰酸的影响无显著的线性规律。[结论]提高卷烟纸助燃剂含量和透气度或降低卷烟纸亚麻配比,均有利于降低卷烟主流烟气中氢氰酸。     

Conditions for purine synthesis: did prebiotic synthesis occur at low temperatures?

The rate of polymerization of hydrogen cyanide to aminomalononitrile and the tetramer, diaminomalonodinitrile, is quadratic in the total cyanide concentration. Since the reactions form part of a plausible prebiotic purine synthesis and since they compete with hydrolysis, concentration of cyanide may have been important. This may be achieved usefully by cooling to separate out ice.     

Spectroscopic detection of stratospheric hydrogen cyanide

A number of features have been identified as absorption lines of hydrogen cyanide in infrared spectra of stratospheric absorption obtained from a high-altitude aircraft. Column amounts of stratospheric hydrogen cyanide have been derived from spectra recorded on eight flights. The average vertical column amount above 12 kilometers is 7.1 +/- 0.8 x 10(14) molecules per square centimeter, corresponding to an average mixing ratio of 170 parts per trillion by volume.     

烟草含氮化合物对卷烟主流烟气氰化氢释放量的影响

[目的]研究卷烟烟气中氰化氢释放量与卷烟中主要含氮化合物的相互关系。[方法]通过在卷烟烟支中添加特定含氮化合物,捕集并测定卷烟烟气中的氰化氢含量,分别研究了6类不同含氮化合物在卷烟燃吸时对烟气中氰化氢释放量的影响,并尝试对氰化氢热解产生的机理和变化规律做了探讨性的解释。[结果]对于烤烟型和混合型卷烟而言,蛋白质、氨基酸、挥发碱、硝酸盐、氮杂环化合物含量的增加导致卷烟烟气中氰化氢的释放量相应增加,且二者间表现显著的相关性关系;各含氮化合物对氰化氢释放量影响程度大小依次为：蛋白质〉氨基酸〉挥发碱〉硝酸盐〉氮杂环。[结论]蛋白质、氨基酸、挥发碱、硝酸盐、氮杂环5类含氮化合物均是卷烟烟气中氰化氢的重要前体物     

植物内生细菌生防作用研究进展

概述植物内生细菌作为生防因子在系统抗性诱导(ISR),抗菌素、2,4-二乙酰间苯三酚(2,4-DAPG)、氰化氢(HCN)、铁载体、水杨酸(SA)和其它易挥发的有机混合物(VOC)产生,及细菌促生作用等方面的研究进展。     

Ciliastatic components in the gas phase of cigarette smoke

The gas phase of cigarette smoke, separated into its components by gas chromatography, was passed across a ciliated specimen. The acetaldehyde, acrolein, and hydrogen cyanide produced strong inhibition of the ciliary beat. A filter which removed most of the acetaldehyde and acrolein from smoke did not reduce the inhibitory effect of the gas phase of that smoke, whereas a filter that removed most of the hydrogen cyanide did reduce inhibition.     

Flash hydrogenation of a bituminous coal

Flash heating of Illinois coal (to 700 degrees C in 1 second) in flowing hydrogen at 100 atmospheres, limiting the vapor residence time at 700 degrees C to 3 seconds, converts 14 percent of the coal's carbon to methane, 7 percent to ethane, and 10 percent to benzene, toluene, and xylenes. The remainder is coke; the carbon balance shows that heavy tar, if any exists, is less than 3 percent.     

The Cassini UVIS stellar probe of the Titan atmosphere

The Cassini Ultraviolet Imaging Spectrometer (UVIS) observed the extinction of photons from two stars by the atmosphere of Titan during the Titan flyby. Six species were identified and measured: methane, acetylene, ethylene, ethane, diacetylene, and hydrogen cyanide. The observations cover altitudes from 450 to 1600 kilometers above the surface. A mesopause is inferred from extraction of the temperature structure of methane, located at 615 km with a temperature minimum of 114 kelvin. The asymptotic kinetic temperature at the top of the atmosphere determined from this experiment is 151 kelvin. The higher order hydrocarbons and hydrogen cyanide peak sharply in abundance and are undetectable below altitudes ranging from 750 to 600 km, leaving methane as the only identifiable carbonaceous molecule in this experiment below 600 km.     

A high-efficiency power cycle in which hydrogen is compressed by absorption in metal hydrides

A high-efficiency power cycle is proposed in which molecular hydrogen gas is used as a working fluid in a regenerative closed Brayton cycle. The hydrogen gas is compressed by an absorption-desorption cycle on metal hydride (FeTiH(x)) beds. Low-temperature solar or geothermal heat (temperature about 100 degrees C) is used for the compression process, and high-temperature fossil fuel or nuclear heat (temperature about 700 degrees C) supplies the expansion work in the turbine. Typically, about 90 percent of the high-temperature heat input is converted to electricity, while about 3 kilowatts of low-temperature heat is required per kilowatt of electrical output.     

Parent volatiles in comet 9P/Tempel 1: before and after impact

We quantified eight parent volatiles (H2O, C2H6, HCN, CO, CH3OH, H2CO, C2H2, and CH4) in the Jupiter-family comet Tempel 1 using high-dispersion infrared spectroscopy in the wavelength range 2.8 to 5.0 micrometers. The abundance ratio for ethane was significantly higher after impact, whereas those for methanol and hydrogen cyanide were unchanged. The abundance ratios in the ejecta are similar to those for most Oort cloud comets, but methanol and acetylene are lower in Tempel 1 by a factor of about 2. These results suggest that the volatile ices in Tempel 1 and in most Oort cloud comets originated in a common region of the protoplanetary disk.     

Synthesis of Isocyanic Acid from Nitric Oxide over Palladium and Iridium Catalysts

A novel and convenient synthesis of isocyanic acid (HNCO) and its trimer isocyanuric acid has been obtained by the conversion of nitric oxide (NO). Nitric oxide, carbon monoxide, and hydrogen mixed in helium at the level of 0.3 to 5 percent reacted over iridium and palladium catalysts at 280 degrees to 450 degrees C to form HNCO in 60 to 75 percent yield. Major side products were ammonium cyanate at low temperature and ammonia or nitrogen at high temperature. Total conversion of nitrogen from NO to NCO reached 73 percent over palladium and 86 percent over iridium.     

Photochemical reactions and the chemical evolution of purines and nicotinamide derivatives

The photochemical rearrangement of a tetramer of hydrogen cyanide to 4-aminoimidazole-5-carbonitrile, a critical step in the proposed prebiotic synthesis of purines, proceeds in high yield in the absence of oxygen without photodestruction of the reaction product. The mechanism of the rearrangement involves the conversion of the excited singlet of the hydrogen cyanide tetramer to 2-imino-3-cyano-4-aminoazetine, which then rearranges to the imidazole product. The photolysis of the vinylogous enaminonitrile 1,3-dicyano4-amino-1,3-butadiene yields 6-aminonicotinonitrile. The latter reaction affords an efficient route to a nicotinamide derivative from cyanoacetylene.     

Use of Trichoderma spp. in remediation of polluted soils and waters

Trichoderma spp. probably have a role in remediation of polluted soils and waters. Highly rhizosphere competent strains persist on roots for an extended period of time (at least months) and continuously interact with the plants. They can increase general plant and root growth and increase uptake of a variety of materials. This makes the Trichoderma-plant interaction highly attractive for use in phytoextraction technologies. Moreover, Trichoderma spp. are resistant to a wide range of toxic…     

Hydrogen partitioning into molten iron at high pressure: implications for Earth's core

Because of dissolution of lighter elements such as sulfur, carbon, hydrogen, and oxygen, Earth's outer core is about 10 percent less dense than molten iron at the relevant pressure and temperature conditions. To determine whether hydrogen can account for a major part of the density deficit and is therefore an important constituent in the molten iron outer core, the hydrogen concentration in molten iron was measured at 7.5 gigapascals. From these measurements, the metal-silicate melt partitioning coefficient of hydrogen was determined as a function of temperature. If the magma ocean of primordial Earth was hydrous, more than 95 mole percent of H2O in this ocean should have reacted with iron to form FeHx, and about 60 percent of the density deficit is reconciled by adding hydrogen to the core.     

一种制备无菌松材线虫的方法

报道了一种通过用H2O2处理松材线虫卵进而获得无菌松材线虫的方法.实验结果表明,15%H2O2处理对松材线虫卵有一定影响,随着处理时间延长,松材线虫孵化率下降,处理30min以上使其孵化率降低至10%以下;15%H2O2处理时间对获得无菌松材线虫有较大影响,其中,处理60min后获得无菌线虫的机率达70%.在无菌条件下...     

Nonequilibrium self-assembly of long chains of polar molecules in superfluid helium

It is shown that in the low-temperature (0.37 kelvin) environment of superfluid helium droplets, long-range dipole-dipole forces acting between two polar molecules can result in the self-assembly of noncovalently bonded linear chains. At this temperature the effective range of these forces is on the nanometer scale, making them important in the growth of nanoscale structures. In particular, the self-assembly of exclusively linear hydrogen cyanide chains is observed, even when the folded structures are energetically favored. This suggests a design strategy for the growth of new nanoscale oligomers composed of monomers with defined dipole (or higher order) moment directions.