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181.
Bin?Qi Akinori?Takami Shiro?HatakeyamaEmail author 《Journal of Atmospheric Chemistry》2005,52(1):63-79
Concentrations of peroxy radicals were measured by a chemical amplification technique at a remote forested site as part of
the Program for Research on Oxidants in a Forested Region in Nikko (PROFRN). During the measurement period of 22–27 July 2002,
the mixing ratios of peroxy radicals averaged for 3 min at midday ranged from 109 to 134 pptv at a height approximately 5
m above the forest canopy. Significant diurnal variation in concentrations of peroxy radicals was observed, with the maximum
usually occurring around noon. Most of the variation was driven by changes in the intensity of solar radiation. However, it
was found that the peroxy radical concentration reached its peak about 3-h later than that of solar radiation on 24 and 26
July. The origins of this delay are discussed based on an analysis of the total radical budget in that period. A transport
of polluted air masses to the site was one of possible causes for the inconsistency. In addition, the measured peroxy radical
concentrations were compared with those derived from the deviations of NO-NO2-O3 photo-stationary state (PSSD) for clear days. The estimated half-hour-average concentrations of peroxy radical were in agreement
with the PERCA measured in the morning and late afternoon. However the two techniques differed by as much as a factor of two
during the time of near midday. 相似文献
182.
G. Herzberg 《Journal of Astrophysics and Astronomy》1984,5(2):131-138
The main bands of the Schüler system of ND4 and NH4 have been observed at high resolution. On the basis of these spectra, Watson, in a separate paper, has analysed the ND4 main band showing that it represents a2F2
→
2 A1 transition of a tetrahedral molecule. The observed wavenumber data for both ND4 and NH4 are presented; the latter have not yet been analysed. Isotopic bands for15ND4,14ND3H,14ND2H2,14NDH3 have also been obtained and as previously pointed out confirm the assumed carrier of the spectrum. The much weaker bands
accompanying the main Schüler band on the short and long wavelength sides are photographed at medium resolution. The interpretation
of these bands in terms of the vibrational levels of upper and lower states is briefly discussed. 相似文献
183.
Bo. R. Larsen Dario Di Bella Marianne Glasius Richard Winterhalter Niels R. Jensen Jens Hjorth 《Journal of Atmospheric Chemistry》2001,38(3):231-276
Smog chamber experiments have beenconducted in which cyclic monoterpenes were oxidisedin the gas phase by OH. The evolved secondary organicaerosol (SOA) was analysed by LC-MSn and thegas-phase products were analysed by FT-IR. Theconcentrations of the identified compoundscorresponded to carbon mass balances in the range of40%–90%. The identified compounds in the particularphase corresponded to 0.5%–4.2% of the reactedcarbon. The most abundant compounds in SOA fromterpenes with an endocyclic C=C double bond wereC10-keto-aldehydes, C10-keto-carboxylicacids, C10-hydroxy-keto-carboxylic acids, andC10-hydroxy-keto-aldehydes (pinonaldehyde,pinonic acid, hydroxy-pinonic acid isomers, andhydroxy-pinonaldehyde isomers from -pinene;3-caronaldehyde, 3-caronic acid, hydroxy-3-caronicacid isomers, and hydroxy-3-caronaldehyde isomers from3-carene). The most abundant compounds in SOA fromterpenes with an exocyclic C=C double bond wereC9-ketones, C9-dicarboxylic acids, andC10-hydroxy-keto-carboxylic acids (nopinone,pinic acid, and hydroxy-pinonic acid isomers from-pinene; sabinaketone, sabinic acid andhydroxy-sabinonic acid isomers from sabinene).Decarboxylated analogues of most of the compounds werepresent in SOA in minor concentrations, such asC9-keto-carboxylic acids (norpinonic acid,nor-3-caronic acid) and C8-dicarboxylic acids(norpinic acid, nor-3-caric acid, norsabinic acid). InSOA from limonene, which contains an endocyclic aswell as an exocyclic C=C double bond, the mostabundant compounds were a C10-keto-aldehyde andits oxo-derivative (limononaldehyde and keto-limononaldehyde) together with hydroxy-derivatives of aC10-keto-carboxylic acid (isomers ofhydroxy-limononic acid). Also aC10-keto-carboxylic acid (limononic acid) waspresent together with minor concentrations of aC9-dicarboxylic acids (limonic acid), itsoxo-derivative (keto-limonic acid), and itsdecarboxylated analogue (norlimonic acid). Mechanisticpathways for the formation of these products, some ofwhich are identified here for the first time, areproposed. 相似文献
184.
185.
鮟鱇是一种低脂肪高蛋白的优质海洋生物资源, 其氨基酸含量丰富, 蛋白质含量高达75.30%。本实验选用胰蛋白酶, 胃蛋白酶, 木瓜蛋白酶和菠萝蛋白酶水解鮟鱇鱼糜, 比较各酶解产物对1, 1-二苯基-2-三硝基苯肼(DPPH)自由基的清除率, 确定木瓜蛋白酶为最佳用酶。在单因素实验基础上进行响应面优化实验, 确定酶解反应的最佳条件为: 加酶量829.51 U/g, pH值7.37, 酶解温度47.09 ℃, 酶解时间5.86 h, 液固比5.79∶1。在最优条件下验证其DPPH自由基清除率为80.22%±0.63%, 接近预测值80.55%。经响应面法实验制备的鮟鱇活性肽粉末呈淡黄色, 具有较好的抗氧化活性, 其羟自由基清除能力的IC50值为1.69 mg/mL, 可作为潜在的抗氧化剂。 相似文献
186.
目的:观察序贯紧线法在小儿多发性肛瘘术中的临床疗效。方法:将78 例多发性肛瘘患儿随机分为治疗组和对照组。在手术过程中,治疗组36例采用序贯紧线法一次性根治,对照组42例采用分期根治术治疗。观察2组的住院时间、治愈时间、术后疼痛程度、治愈情况、肛门功能评分及肛门畸形、肛门狭窄、复发情况。结果:与对照组比较,治疗组住院时间、治愈时间均缩短,差异均有统计学意义(P<0.01);2组术后疼痛评分、治愈率、肛门功能评分及肛门畸形、肛门狭窄、复发例数比较,差异均无统计学意义(P>0.05)。结论:序贯紧线法治疗能缩短小儿多发性肛瘘术后的住院时间及愈合时间,具有较好的临床疗效与安全性。 相似文献