麦饭石对NOx的吸附

研究了麦饭石在不同预处理方法、粒径、活化温度、NOx初始质量浓度和吸附时间等条件下对NOx的吸附性能。实验结果显示：粒径为0.18mm的麦饭石经过400～600℃活化1h后,NOx吸附率大于99%,饱和吸附量大于6.3m g/g。经4次重复活化后,麦饭石对NOx的吸附效果仍然很好,可作为处理含NOx废气的吸附剂。     

Cooperative analysis of infrastructure perfection and residents’ living standards in poverty-stricken counties in Qinghai Province

Environment, Development and Sustainability - The western region of China has always been the main battlefield for poverty alleviation. It is essential to explore the interaction mechanism between...     

侧柏、香樟枝叶挥发物对人体生理的影响

利用多导电生理技术手段,采用与情绪有较大关系的最常见的生理指标为因变量,从嗅觉的角度研究侧柏和香樟两种常见绿化树种的挥发物对人体的影响,结果表明：嗅闻侧柏（Platycladus orientalis（L）Franco）挥发物后人体手指温度极显著升高,人体血氧含量略有增加,平均心率、心电RR间期值显著降低;嗅闻香樟（Cinnamomum camphora（L）Presl）气味后人体手指温度、血氧含量显著降低,平均心率略有变化,心电RR间期值极显著升高。说明人处在侧柏环境中情绪趋于放松状态,感觉清新、舒爽、愉悦;而在香樟气味环境中人表现出紧张、不快,甚至长时间在这样的环境中会产生厌恶情绪。研究结果有助于从植物保健功能指导人居、游憩环境中绿化树种的科学配置。     

Evaluation of endocrine disruption and dioxin-like effects of organic extracts from sewage sludge in autumn in Beijing,China

Study on effective disposal and utilization of sewage sludge has recently been the target of growing interest in China. However, potential risks are associated with the use of sludge due to its contamination with toxic organics, heavy metals and pathogenic microorganisms. In this study, a screening assessment was conducted on sewage sludge samples collected from 17 different sewage treatment plants in Beijing, based on a batch of in vitro bioassays, including a set of recombinant gene yeast assays for endocrine disruption, and an ethoxy resorufin-O- deethylase （EROD） assay using H4IIE cells for aryl hydrocarbon receptor （Ah-R） agonistic activities. Our results suggested that moderate levels of estrogen receptor agonistic activities （0.9 ng E2. g-1 to 6.8 ng E2. gl, dw）, but relative higher androgen receptor antagonistic activ- ities （nd to 45%）, progestin receptor antagonistic activities （nd to 80%） and Ah-R agonistic activities （1390 to 6740 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin （TCDD）·g-1, dw） were found in sewage sludge samples. However, there were no significant correlations between the toxic effects of sewage sludge and the sewage treatment processes. In addition, the 17β-estradiol （E2） equivalent quantity （EEQ） level of the sewage sludge was increased after the composting treatment, whereas the 2,3,7,8-tetrachlorodi- benzo-p-dioxin toxic equivalent quantity （TEQ） level of sewagesludge composted was much lower than that of sewage sludge.     

Novel synthetic approaches and TWC catalytic performance of flower-like Pt/CeO2

A novel Ultrasonic Assisted Membrane Reduction （UAMR）-hydrothermal method was used to prepare flower-like Pt/CeO2 catalysts. The texture, physical/chemical properties, and reducibility of the flower-like Pt/CeO2 catalysts were characterized by X-Ray Diffraction （XRD）, Scanning Electron Microscope （SEM）, Transmission Electron Microscope （TEM）, N2 adsorption, and hydrogen temperature programmed reduction （HE-TPR） techniques. The catalytic performance of the catalysts for treating automobile emission was studied relative to samples prepared by the conventional wetness impregnation method. The Pt/CeO2 catalysts fabricated by this novel method showed high specific surface area and metal dispersion, excellent three-way catalytic activity, and good thermal stability. The strong interaction between the Pt nanoparticles and CeO2 improved the thermal stability. The Ce4＋ ions were incorporated into the surfactant chains and the Pt nanoparticles were stabilized through an exchange reaction of the surface hydroxyl groups. The SEM results demonstrated that the Pt/CeO2 catalysts had a typical three-dimensional （3D） hierarchical porous struc- ture, which was favorable for surface reaction and enhanced the exposure degree of the Pt nanoparticles. In brief, the flower-like Pt/CeO2 catalysts prepared by UAMR-hydrothermal method exhibited a higher Pt metal dispersion, smaller particle size, better three-way catalytic activity, and improved thermal stability versus conven- tional materials.     

银—氧化镉的清洁生产工艺

采用“粉未冶金法”生产Ａｇ—ＣｄＯ。该方法工艺简单，生产周期短，生产效率高。在整个生产工艺过程中，采用密闭型的设备操作，控制生产工艺过程中氧化粉尘逸出，研究出了Ａｇ—ＣｄＯ无（微）公害生产工艺。经监测，氧化镉浓度达到国家《工业企业设计卫生标准》（ＴＪ３６—７９）的要求。     

Evaluation of a prenatal screening procedure for β-thalassaemia carriers in a chinese populationbased on the mean corpuscular volume (MCV)

Haemoglobin A₂ (HbA₂) levels were determined on 25 β-thalassaemia carriers by the microcolumn method and were found to range from 4.5–7.2 per cent (mean 5.2±0.82 S.D.). The haemoglobin level (Hb), mean corpuscular volume (MCV), plasma ferritin and HbA₂ levels were measured on a further 299 cconsecutive Chinese pregnant women at a gestation of less than 24 weeks. 18 patients (6 per cent) had HbA₂ level greater than 4.5 per cent and were diagnosed to be β-thalassaemic carriers. It was observed that all these patients had a MCV below 75 fl. If this level is selected in a screening procedure based on measurement of MCV alone all β-thalassaemia carriers could be detected and 11 per cent of the population screened would require HbA₂ estimation. At a lower cut-off level of 70 fl, 8 per cent of the population screened wouid require HbA₂ measurement (a decrease of 27 per cent) but the detection rate will be lowered considerably (83 per cent). The high false positive rate at all cut-off levels of MCV was largely due to the prevalence of iron deficiency anaemia in the population. Estimation of plasma ferritin level in patients with low MCV will reduce this false positive rate, but there will be a considerable delay in diagnosis in patients with concomitant iron deficiency and β-thalassaemia. The presence of iron deficiency in β-thalassaemia carriers did not reduce their HbA₂ level below the diagnostic range in this study. Measurement of Hb level did not appear to be useful as a screening method since one third of the β-thalassaemia carriers had a Hb level over 11 g/dl. The validity of the MCV cut-off levels derived from the first part of the study was assessed in screening a larger population. 61 β-thalassaemia carriers (6 per cent) were detected out of 1166 patients screened. This incidence was not significantly different from the first part of the study. All these 61 patients had a MCV less than 75 ml. It was concluded that a two-step screening policy, based on MCV measurement followed by HbA₂ estimation when the MCV value is less than 75 fl, is suitable for our population. It is efficient, straight forward with excellent sensitivity and required less time and effort for both laboratory staff and clinicians.     

Stability studies of cholesterol lowering statin drugs in aqueous samples using HPLC and LC–MS

In this study, stability of statin drugs in different conditions, such as various pH, diverse solvents ratio, presence of UV, and sunlight have been investigated. Results suggest strong dependence of statins upon pH, potential environmental persistence towards sun light, and UV light degradation via singlet excited state obtained by excitation into the π–π* band. In acidic conditions interconversion between lactone and hydroxy acid forms in aqueous solutions at room temperature is retarded, while for the same sun-exposed samples are accelerated. Longer exposures lead to the degradation processes. Statin interconversion in water is much lower than in acetonitrile.     

Complexation of iron by salicylic acid and its effect on atrazine photodegradation in aqueous solution

The photodegradation of atrazine and the photochemical formation of Fe(II) and H₂O₂ in aqueous solutions containing salicylic acid and Fe(III) were studied under simulated sunlight irradiation. Atrazine photolysis followed first-order reaction kinetics, and the rate constant (k) corresponding to the solution of Fe(III)-salicylic acid complex (Fe(III)-SA) was only 0.0153 h^?1, roughly one eighth of the k observed in the Fe(III) alone solution (0.115 h^?1). Compared with Fe(III) solution, the presence of salicylic acid significantly enhanced the formation of Fe(II) but greatly decreased H₂O₂ generation, and their subsequent product, hydroxyl radical (˙OH), was much less, accounting for the low rate of atrazine photodegradation in Fe(III)-SA solution. The interaction of Fe(III) with salicylic acid was analyzed using Fourier-transform infrared (FTIR) spectroscopy and UV-visible absorption, indicating that Fe(III)-salicylic acid complex could be formed by ligand exchange between the hydrogen ions in salicylic acid and Fe(III) ions.