Nitric oxide reduction coupled with carbon monoxide oxidation in the presence of soluble metal catalysts

Solutions of RhCl(3).xH(2)O in ethanol and Ru(NO)(2)[P(C(6)H(5))(3)](2) in benzene catalyze the reduction of nitric oxide to nitrous oxide concomitant with the oxidation of carbon monoxide to carbon dioxide at ambient temperature and atmospheric pressure. The reaction, which is followed by gas chromatography and by the decrease in pressure of the system, proceeds to 47 percent conversion of the reactants after 63 hours.     

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.     

Stratospheric Mean Ages and Transport Rates from Observations of Carbon Dioxide and Nitrous Oxide

Measurements of stratospheric carbon dioxide (CO2) and nitrous oxide (N2O) concentrations were analyzed to investigate stratospheric transport rates. Temporal variations in tropospheric CO2 were observed to propagate into the stratosphere, showing that tropospheric air enters the lower tropical stratosphere continuously, ascends, and is transported rapidly (in less than 1 month) to both hemispheres. The mean age A of stratospheric air determined from CO2 data is approximately 5 years in the mid-stratosphere. The mean age is mathematically equivalent to a conserved tracer analogous to exhaust from stratospheric aircraft. Comparison of values for A from models and observations indicates that current model simulations likely underestimate pollutant concentrations from proposed stratospheric aircraft by 25 to 100 percent.     

Py-GC-MS法研究硼及磷化合物对木质素热解产物的影响

采用裂解-气相色谱-质谱(Py-GC-MS)联机分析技术,研究了含硼及磷的化合物对紫椴(Tilia amurensis)木质素热解产物组成的影响。结果表明:木质素在裂解过程中,产生大量的CO2、CO、H2O,其主要原因是高温时羰基、羧基、羟基、甲基等脱除反应以及多环芳香族化反应的深入进行,而所选用的阻燃剂大多数都促进了CO2、CO和H2O的产生。没有经过阻燃处理的木质素热解产物中脂肪族可挥发有机化合物的比例较大,硼酸和有机磷酸盐处理过的木质素在裂解过程中这些化合物的比例明显减少。无机磷酸盐和硼砂有效降低木质素热解过程中芳香族化合物及杂环化合物的比例。FRW阻燃剂中GUP和硼酸对木质素热解过程的影响,并不是简单的加和作用,而表现出协同效应,并初步鉴定了紫椴木质素裂解产物中94种化合物的结构。     

柠檬酸和苹果酸在卷烟阴燃状态下的燃烧行为和机制研究

[目的]比较研究柠檬酸和苹果酸在卷烟阴燃状态下的燃烧行为和机制。[方法]利用微燃烧量热仪(MCC)考察升温速率对柠檬酸和苹果酸燃烧行为的影响;利用热重-红外联用仪(TG-FTIR)比较研究其燃烧过程,特别是主要热解气相产物的形成规律,探讨其燃烧机理。[结果]MCC测试结果发现,在相同的燃烧条件下,柠檬酸的易燃性优于苹果酸,但燃烧性稍差于苹果酸;升温速率对柠檬酸和苹果酸燃烧行为的影响很大。TG-FTIR测试结果发现,柠檬酸和苹果酸的燃烧行为主要取决于热解气相产物的生成;柠檬酸相对于苹果酸更易发生热分解,且在热解过程中生成更多的H2O、CO2、CO和羰基化合物。[结论]初期相对较弱的热解稳定性和热解气相产物中可燃性气体和不可燃性气体的相对组成,共同决定了柠檬酸易燃性强于苹果酸而燃烧性稍弱于苹果酸的燃烧行为。     

臭氧化降解除草剂2,4-D的机理研究(I):中间产物分析

苯氧羧酸类除草剂2,4-D是一种常见的农业污染物,具有较高的环境危害。将水中的除草剂2,4-D作为控制对象,采用臭氧、臭氧/过氧化氢两个氧化体系在实验室内进行降解。为了探讨2,4-D降解机理,分别采用气相色谱-质谱联机分析方法、高效液相色谱法、离子色谱法等方法对2,4-D的降解过程中可能产生的中间产物进行了检测。结果表明,2,4-D的臭氧化降解中间产物有芳香族化合物和有机酸等,主要包括:2,4-二氯苯酚、(氯)对苯二酚(邻苯二酚)、(氯)苯醌、顺丁烯二酸、反丁烯二酸、乙酸、草酸、甲酸等。并经过总有机碳分析可知,部分2,4-D经过臭氧、臭氧/过氧化氢体系氧化降解,在反应时间内能彻底降解为二氧化碳、水及某些无机物等终产物。对2,4-D降解中间产物的分析为臭氧化降解除草剂2,4-D降解路径的研究打下基础。     

秸秆还田对稻麦两熟高产农田净增温潜势影响的初步研究

对长江下游稻麦两熟农田生态系统2009—2010年的CH4和N2O排放以及土壤碳固定进行了分析,初步研究了秸秆还田对稻麦两熟高产农田净增温潜势的影响。结果表明,秸秆还田对稻麦两熟高产农田周年CH4和N2O排放总量、土壤碳固定量以及净增温潜势均有显著或极显著影响:秸秆还田条件下周年CH4、N2O排放总量分别为394 kg CH4.hm-2、2.39 kg N2O.hm-2,土壤碳固定量、净增温潜势分别为1.14 t C·hm-2、6383 kg CO2-equivalents·hm-2;较秸秆不还田增加CH4排放总量152%、减少N2O排放总量14%、增加土壤碳固定量531%、增加净增温潜势57%。以上结果表明,秸秆还田使短期内稻麦两熟高产农田的温室效应明显提高,但其长期效果如何还有待观测。     

Synthesis of ammonium cyanate and urea by reduction of nitric oxide on platinum, rhodium, and ruthenium catalysts

Nearly quantitative conversion of nitric oxide (NO) into N(2)H(4)CO has been obtained in the reduction of NO with carbon monoxide and hydrogen over platinum and rhodium catalysts. Depending on the temperature of collection, N(2)H(4)CO is isolated as ammonium cyanate or its isomer, urea. The process is an effective way of recovering fixed nitrogen from dilute industrial streams containing NO. Ammonium cyanate may play a role in the reduction of NO in automotive exhaust control.     

华南地区典型人工林土壤二氧化碳和氧化亚氮通量研究

二氧化碳（CO2）和氧化亚氮（N2O）是重要的温室气体,森林土壤是其主要排放源。采用静态箱/气相色谱分析技术对中国科学院鹤山丘陵综合开放试验站尾叶桉Eucalyptus urophylla纯林（EUp）,厚荚相思Acacia crassicarpa纯林（ACp）,10个树种混交林（Tp）和30个树种混交林（THp）等4种林型的土壤CO2和N2O排放通量进行了原位测定,研究纯林和混交林对土壤温室气体排放的影响。结果表明：CO2和N2O排放通量季节波动幅度较大;4个林型土壤CO2和N2O通量在湿季均维持较高水平;通量峰值均出现在湿季,旱季则明显降低,且相对稳定。由于EUp和ACp纯林土壤微生物碳（microbial biomass carbon,MBC）比混交林高,导致EUp（130.67 mg.m-2.h-1）和ACp（134.65 mg.m-2.h-1）土壤CO2通量显著高于Tp（111.39 mg.m-2.h-1）和THp（108.53 mg.m-2.h-1）。在4种林型中,尾叶桉对土壤NO3-N吸收快速,土壤N2O排放通量最低,达12.45μg.m-2.h-1。土壤温度、土壤湿度、MBC和呼吸底物[NO3-N和土壤有机碳（soil organic carbon,SOC）]都是影响土壤CO2和N2O通量的重要因子。图2表3参29     

外源NO调控红松幼苗光合作用与抗氧化酶活性的浓度效应

[目的]探讨不同浓度外源NO对红松针叶光合色素和抗氧化酶活性的影响。[方法]以3年生红松针叶为试验材料,测定喷施不同浓度外源NO供体硝普钠溶液(0、0.01、0.10、0.50和1.00 mmol/L SNP)处理下其光合色素含量、抗氧化酶活性、丙二醛(MDA)含量和过氧化氢(H_2O_2)含量等生理指标。[结果]净光合速率(Pn)、蒸腾速率(Tr)和呼吸速率(Rd)会随着SNP浓度增加而增加,分别在SNP喷施0.10和0.50 mmol/L时达到最大值;喷施0.01 mmol/L SNP有效提高了气孔导度(Gs)、胞间CO_2浓度(Ci)、光合色素含量、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性,而超氧化物歧化酶(SOD)活性、H_2O_2含量和MDA含量在喷施外源NO时显著降低。[结论]施加适量浓度外源NO会显著增加光合参数、光合色素含量、CAT活性、抗坏血酸过氧化物酶(APX)活性、POD活性,但施加外源NO降低了SOD活性、H_2O_2含量、MDA含量,从而降低了细胞膜脂过氧化程度,减轻了红松幼苗受到的伤害。     

Stratospheric response to trace gas perturbations: changes in ozone and temperature distributions

The stratospheric concentration of trace gases released in the atmosphere as a result of human activities is increasing at a rate of 5 to 8 percent per year in the case of the chlorofluorocarbons (CFCs), 1 percent per year in the case of methane (CH(4)), and 0.25 percent per year in the case of nitrous oxide (N(2)O). The amount of carbon dioxide (CO(2)) is expected to double before the end of the 21st century. Even if the production of the CFCs remains limited according to the protocol for the protection of the ozone layer signed in September 1987 in Montreal, the abundance of active chlorine (2 parts per billion by volume in the early 1980s) is expected to reach 6 to7 parts per billion by volume by 2050. The impact of these increases on stratospheric temperature and ozone was investigated with a two-dimensional numerical model. The model includes interactive radiation, wave and mean flow dynamics, and 40 trace species. An increase in CFCs caused ozone depletion in the model, with the largest losses near the stratopause and, in the vertical mean, at high latitudes. Increased CO(2) caused ozone amounts to increase through cooling, with the largest increases again near 45 kilometers and at high latitudes. This CO(2)-induced poleward increase reduced the CFC-induced poleward decrease. Poleward and downward ozone transport played a major role in determining the latitudinal variation in column ozone changes.     

Isotopic composition of the martian atmosphere

Results from the neutral mass spectrometer carried on the aeroshell of Viking 1 show evidence for NO in the upper atmosphere of Mars and indicate that the isotopic composition of carbon and oxygen is similar to that of Earth. Mars is enriched in (15)N relative to Earth by about 75 percent, a consequence of escape that implies an initial abundance of nitrogen equivalent to a partial pressure of at least 2 millibars. The initial abundance of oxygen present either as CO(2) or H(2)O must be equivalent to an exchangeable atmospheric pressure of at least 2 bars in order to inhibit escape-related enrichment of (18)O.     

Oceanic Uptake of Fossil Fuel CO2: Carbon-13 Evidence

The delta(13)C value of the dissolved inorganic carbon in the surface waters of the Pacific Ocean has decreased by about 0.4 per mil between 1970 and 1990. This decrease has resulted from the uptake of atmospheric CO(2) derived from fossil fuel combustion and deforestation. The net amounts of CO(2) taken up by the oceans and released from the biosphere between 1970 and 1990 have been determined from the changes in three measured values: the concentration of atmospheric CO(2), the delta(13)C of atmospheric CO(2) and the delta(13)C value of dissolved inorganic carbon in the ocean. The calculated average net oceanic CO(2) uptake is 2.1 gigatons of carbon per year. This amount implies that the ocean is the dominant net sink for anthropogenically produced CO(2) and that there has been no significant net CO(2) released from the biosphere during the last 20 years.     

Venting of carbon dioxide-rich fluid and hydrate formation in mid-okinawa trough backarc basin

Carbon dioxide-rich fluid bubbles, containing approximately 86 percent CO(2), 3 percent H(2)S, and 11 percent residual gas (CH(4) + H(2)), were observed to emerge from the sea floor at 1335- to 1550-m depth in the JADE hydrothermal field, mid-Okinawa Trough. Upon contact with seawater at 3.8 degrees C, gas hydrate immediately formed on the surface of the bubbles and these hydrates coalesced to form pipes standing on the sediments. Chemical composition and carbon, sulfur, and helium isotopic ratios indicate that the CO(2)-rich fluid was derived from the same magmatic source as dissolved gases in 320 degrees C hydrothermal solution emitted from a nearby black smoker chimney. The CO(2)-rich fluid phase may be separated by subsurface boiling of hydrothermal solutions or by leaching of CO(2)-rich fluid inclusion during posteruption interaction between pore water and volcanogenic sediments.     

Effects of 1-Methylcyclopropene on NO Content, NOS Activity, and H2O2 Content in Postharvest Suli Pears

Studies were conducted over the effects of 1-methylcycolpropene (1-MCP) treatment on postharvest life of Suli pears (Pyrus bretschneideri Rehd.) stored at room and cold temperatures on nitric oxide (NO), nitric oxide synthase (NOS)activity, and hydrogen dioxide (H2O2). Results showed that the 1-MCP treatment had little effect on total soluble solids (TSS) at both room and cold temperatures. 1-MCP delayed softening of Suli pear fruits, decreased respiratory rate and H2O2 accumulation, and increased NO and NOS activity at room temperature storage, while the effect of cold temperature storage was relatively inferior. There was a significant positive correlation between NOS activity and NO content. It is concluded that 1-MCP had effects on endogenous NO content and accumulation of H2O2. Similarly, H2O2 acting as a signaling molecule via regulating NO level affects the ripening and senescence of Suli pears.     

牛粪不同堆肥模式对温室气体排放的影响

采用静态箱-气相色谱法研究了自然状态下牛粪(C)、牛粪+秸秆(CSt)、牛粪+土(CSo)、牛粪+秸秆+土(CSt So)4种堆肥模式对温室气体排放的影响,以期为温室气体减排和堆肥模式优化提供参考。结果表明:堆肥期间堆温和温室内气温随时间推进均呈升—降—升的趋势,同一观测时间点气温高于堆温,总体上CSt、CSt So处理的堆温略高于C、CSo处理,表明加入秸秆具有提高堆温的效果。随时间推进,C处理的CO_2、CH_4和N_2O排放通量总体均呈增加的趋势,第6~7周排放通量较大;CSt、CSo、CSt So处理的3种温室气体排放通量总体均呈先升后降的趋势,CO_2和CH_4排放通量最大值总体出现在第2周,N_2O排放通量在第5~6周时较大。CO_2平均排放通量表现为CStCSt SoCSoC,除C处理与CSo处理无显著差异外,其他处理间差异显著;CH_4平均排放通量表现为CCStCSt SoCSo,C处理与CSt、CSo、CSt So处理之间及CSt、CSo处理之间差异显著;N_2O平均排放通量表现为CSoCStCSt SoC,CSo处理与C处理差异显著。CSt、CSo、CSt So处理的全球增温潜势(GWP)分别是C处理的3.25、2.61、2.59倍,主要是由于CSt、CSo、CSt So处理的CO_2和N_2O排放总量显著高于C处理,其对GWP的贡献率均高达97%以上。综合考虑广大农村堆料实际组分及温室气体减排,建议采用CSt So堆肥模式,但应适当增加牛粪和土的用量。     

Ionosphere of venus: first observations of the dayside ion composition near dawn and dusk

The first in situ measurements of the composition of the ionosphere of Venus are provided by independent Bennett radio-frequency ion mass spectrometers on the Pioneer Venus bits and orbiter spacecraft, exploring the dawn and duskside regions, respectively. An extensive composition of ion species, rich in oxygen, nitrogen, and carbon chemistry is idenitified. The dominant topside ion is O(+), with C(+), N(+), H(+), and He(+) as prominent secondary ions. In the lower ionosphere, the ionzization peak or F(1) layer near 150 kilometers reaches a concentration of about 5 x l0(3) ions per cubic centimeter, and is composed of the dominant molecular ion, O(2)(+), with NO(+), CO(+), and CO(2)(+), constituting less than 10 percent of the total. Below the O(+) peak near 200 kilometers, the ions exhibit scale heights consistent with a neutral gas temperature of about 180 K near the terminator. In the upper ionosphere, scale heights of all species reflect the effects of plasma transport, which lifts the composition upward to the often abrupt ionopause, or thermal ion boundary, which is observed to vary in height between 250 to 1800 kilometers, in response to solar wind dynamics.     

外源NO对采后芒果果实低温胁迫后H2O2代谢的影响

一氧化氮（NO）是植物体内重要的信号分子。为了探讨NO对采后芒果低温胁迫后果实过氧化氢（H2O2）及抗氧化酶的影响,分别采用0.08 mmol/L NO供体SNP溶液和30 μL/L NO气体处理采后青芒果果实,并于3℃低温贮藏12 d后,检测芒果果皮和果肉中H2O2含量和相关抗氧化酶的活性。结果表明,外源NO浸泡处理能显著降低低温胁迫后芒果果皮中H2O2水平,提高超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的活性,其中NO对CAT活性的影响最大,可能是外源NO处理调控H2O2水平的关键作用点。NO供体SNP处理效果优于NO气体处理,主要作用部位为芒果果皮。     

稻鸭、稻鱼共作生态系统CH4和N2O温室效应及经济效益评估

 【目的】稻鸭、稻鱼共作生态系统是中国南方稻作区两种主要复合种养模式。研究稻鸭、稻鱼共作生态系统中CH4和N2O排放产生的温室效应并对其经济价值进行评价,旨在为进一步开发利用稻田综合利用模式提供理论基础和实践依据。【方法】采用静态箱技术,研究稻鸭、稻鱼共作生态系统CH4和N2O排放规律,并运用增温潜势对稻鸭、稻鱼共作生态系统CH4和N2O排放的温室效应及经济效益进行估算。【结果】在水稻生长期间,稻鸭、稻鱼共作系统中CH4排放峰值均出现在分蘖盛期和抽穗期,其平均排放通量均显著（P＜0.05）低于常规淹水稻田;N2O 的排放通量在稻田淹水期间保持较低值,而在稻田落干后迅速升高。养鸭显著（P＜0.05）提高了稻田N2O的排放,养鱼降低了稻田N2O的排放。2006和2007年稻鸭、稻鱼处理CH4和N2O排放产生总温室效应分别为4 728.3、4 611.0 kg CO2?hm-2和4 545.0、4 754.3 kg CO2?hm-2,其温室效应成本分别为970.89、946.81 yuan/hm2和933.25和976.23 yuan/hm2,明显低于CK的5 997.6和5 391.5 yuan/hm2。除去CH4和N2O排放产生温室效应的环境成本,采用稻鸭、稻鱼生态种养技术的经济效益分别比常规稻田增加2 210.64、4 881.92 yuan/hm2和3 798.37、5 310.64 yuan/hm2。【结论】稻鸭、稻鱼共作能有效的抑制稻田温室气体排放并显著降低其温室效应。因此,稻鸭、稻鱼共作是减少温室气体排放的有效措施之一,具有较好的推广价值。     

Synthesis of Graphite and Hydrocarbons by Reaction between Calcite and Hydrogen

The reaction of calcite with hydrogen was investigated over a range of pressure, temperature, and time. The reaction initiates at about 500 degrees C. Its primarily temperature-dependent rateproceeds in a crystallographically anisotropic manner, and reaction products are CaO, Ca(OH)(2), H(2)O, CO, CH(4), C2H(6), and C (graphite), plus a black solid residue that may be hydrocarbon.