Methane,carbon monoxide and methylchloroform in the southern hemisphere

New observational data on CH₄, CO and CH₃CCl₃ in the southern hemisphere are reported. The data are analysed for long term trends and seasonal cycles. CH₃CCl₃ data are used to scale the OH fields incorporated in a two dimensional model, which in turn, is used to constrain the magnitude of a global CH₄ source function. The possible causes of observed seasonality of CH₃CCl₃, CH₄ and CO are identified, and several other aspects of observed CH₄ variability are discussed.Possible future research directions are also given.     

The NO2-O3 system at sub-ppm concentrations: Influence of temperature and relative humidity

The stoichiometry and kinetics of the reaction of NO₂ with O₃ at sub-ppm concentration level have been investigated as a function of temperature and relative humidity. The experiments were performed in a continuous flow reactor using chemiluminescent and wet chemical methods of analysis.The rate constant found can be described by the Arrhenius expression: % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x% fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaiikaiaaik% dacaGGUaGaaGyoaiaaiEdacqGHXcqScaaIWaGaaiOlaiaaigdacaaI% 0aGaaiykaiabgEna0kaaigdacaaIWaWaaWbaaSqabeaacqGHsislca% aIXaGaaG4maaaakiaabwgacaqG4bGaaeiCaiaacIcadaWcgaqaaiaa% cIcacqGHsislcaaIYaGaaGOnaiaaikdacaaIWaGaeyySaeRaaGyoai% aaicdacaGGPaaabaGaamivaiaacMcacaqGGaGaae4yaiaab2gadaah% aaWcbeqaaiaabodaaaGccaqGGaWaaSGbaeaacaqGTbGaae4BaiaabY% gacaqGLbGaae4yaiaabwhacaqGSbGaaeyzamaaCaaaleqabaGaaeyl% aiaabgdaaaaakeaacaqGZbWaaWbaaSqabeaacaqGTaGaaeymaaaaaa% aaaaaa!62A3!\[(2.97 \pm 0.14) \times 10^{ - 13} {\text{exp}}({{( - 2620 \pm 90)} \mathord{\left/ {\vphantom {{( - 2620 \pm 90)} {T){\text{ cm}}^{\text{3}} {\text{ }}{{{\text{molecule}}^{{\text{ - 1}}} } \mathord{\left/ {\vphantom {{{\text{molecule}}^{{\text{ - 1}}} } {{\text{s}}^{{\text{ - 1}}} }}} \right. \kern-\nulldelimiterspace} {{\text{s}}^{{\text{ - 1}}} }}}}} \right. \kern-\nulldelimiterspace} {T){\text{ cm}}^{\text{3}} {\text{ }}{{{\text{molecule}}^{{\text{ - 1}}} } \mathord{\left/ {\vphantom {{{\text{molecule}}^{{\text{ - 1}}} } {{\text{s}}^{{\text{ - 1}}} }}} \right. \kern-\nulldelimiterspace} {{\text{s}}^{{\text{ - 1}}} }}}}\] and are independent of the relative humidity. As commonly encountered in previous studies a lower-than-two reaction stoichiometry is observed.Heterogeneous reactions occurring at the reactor wall seem to be essential in the reaction mechanism. The NO₃ wall conversion to NO₂ and the N₂O₅ wall scavenging in the presence of H₂O are suggested to account for the observed stoichiometric factors.     

Nonaqueous titration of functional groups in humic acid

Humic acid was titrated by sodium methoxide in dimethylsulfoxide using platinum-calomel electrode systems. Adding benzoic acid and phenol as internal standards to humic acid yielded two inflections. The titer at the first inflection point was equivalent to the carboxyl groups whose pK_a (H₂O) values were less than 7. The difference between the titers at the two inflection points was equivalent to the phenolic hydroxyl groups whose pK_a (H₂O) values were 7–10. Calculated results for the carboxyl and phenolic hydroxyl groups in humic acid obtained by the nonaqueous titration method agreed closely with those obtained by conventional methods.     

Electron paramagnetic resonance characteristics of the humic acids from a podzol

A study has been made of solid and solution electron paramagnetic resonance (EPR) spectra of humic acids from different horizons in a podzolic soil. Hyperfine splitting was observed in the solution spectra of humic acids from all horizons and depended on the strength of alkali and the period of dissolution. The upper organic horizons L, F and O₁ contained humic acids with some spectral characteristics in common with lignin. Humic acid from the lower horizons showed different spectra. At least 5 different radical signals were present.     

CCSD超高压变质岩中金红石结构水（OH^-）的傅里叶变换红外光谱测定及其地球动力学意义

名义上无水矿物(NAMs)的结构水研究是认识超高压变质作用(UHPM)过程中流体活动规律的重要手段,并对板块汇聚边缘大陆动力学及水的深部地球循环有重要意义。本文采用傅立叶变换红外光谱(非偏振光)研究了中国大陆科学钻探(CCSD)主孔岩心及其周围地表榴辉岩中副矿物—金红石中的结构水。所有测试样品都在3285 cm~(-1)和3295 cm~(-1)附近产生尖锐的吸收峰,证实“水”以结构羟基(OH~-)的形式赋存于金红石晶格之中。采用最新标定的摩尔吸收系数[38000 L/(mol·cm~2)]计算表明,金红石结构水含量在324×10~(-6)～523×10~(-6)范围内,远较前人有关金红石结构水含量的计算结果为低。同时,结构水分布不均一性在不同样品之间和颗粒内部都有明显表现,指示超高压变质过程中有限的流体活动和快速的板块俯冲—折返过程。     

Uptake of the NO <Subscript>3</Subscript> Radical on Aqueous Surfaces

Using a single drop experiment, the uptake of NO₃ radicals on aqueous solutions of the dye Alizarin Red S and NaCl was measured at 293 K. Uptake coefficients in the range (1.7–3.1) ⋅ 10^{− 3} were measured on Alizarin Red S solutions. The uptake coefficients measured on NaCl solutions were in the range of (1.1–2.0) ⋅ 10⁻³ depending on the salt concentration. Both experiments lead to a consistent result for the mass accommodation coefficient of α_NO3 = (4.2_{− 1.7}^+2.2)⋅ 10⁻³. The product H(D_l k_Cl−^II)^0.5 for the NO₃ radical was determined to be (1.9 ± 0.2) M atm^{− 1} cm s^−0.5 M^−0.5 s^−0.5 by fitting the uptake data for the NaCl solutions to the so-called resistance model. The yield of the chemical NO₃ radical source was characterized using UV-VIS and FT-IR spectroscopy. The amount of gas-phase NO₃ radicals measured at elevated humidities was less than expected. Instead, a rise of the gas-phase HNO₃ concentration was found indicating a conversion of gas-phase NO₃ radicals to gas-phase HNO₃ on the moist reactor walls.     

海泡石吸附纳米TiO2对·OH基产生的影响

用X射线衍射(XRD)、扫描电子显微镜(SEM)对海泡石结构和形貌以及吸附纳米二氧化钛的海泡石的形貌进行了观察;采用BET法(以氮气为吸附气体)测定海泡石吸附纳米二氧化钛的比表面积的变化,用电子自旋波谱仪ESR对海泡石吸附纳米二氧化钛产生羟基自由基(·OH)的能力进行表征。研究结果发现,海泡石对纳米二氧化钛有较好的吸附、分散作用,在自然光条件下可产生·OH,且在355nm波长照射条件下产生·OH的能力增强。这不仅解决了纳米材料团聚、不易分散的问题,而且增强了纳米材料的光催化性能。     

西藏日土以东地区蚀变遥感异常特征

根据蚀变岩的TM波谱特征,在日土县以东地区进行了蚀变岩遥感信息提取。通过对研究区羟基（OHA）和铁染（FCA）两种异常的分析,为下一步地质调查工作提出建议。     

CONVERSION RATES OF SURFACE HOX RADICALS IN BEIJING CITY

1INTRODUCTIONThe hydroxyl radicals play a central role in atmospher-ic photochemistry, reacting with a lot of compounds, often initiating their oxidation and subsequent loss and resulting in the formation of ozone and other deleteri-ous oxidants, acids, and fine particles in polluted ar-eas. A thorough understanding of this role is necessary for efficient, cost-effective pollution control. There-fore, the measurement of OH is very significant (E-HHAT etal., 1991). Nevertheless, most me…