高温液相色谱法在中药成分检测中的应用

采用高温操作,对六味地黄丸的有效成分进行了分析。当柱温提高到60℃时,采用黏度大而洗脱能力强的异丙醇混合物为流动相,分离时间比升温前缩短30 min;总峰数目为83,其中紫外检测器可识别峰个数为65,蒸发光散射检测器可识别峰个数为59。     

上海大气总悬浮颗粒物中金属的可溶性特征

大气颗粒物中金属的可溶性对于评估金属的生物可利用性和环境迁移性具有重要意义.采集上海大气总悬浮颗粒物(TSP)样品,利用高分辨率电感耦合等离子体质谱,测定经微循环淋溶提取的金属水、酸(p H=2)可溶含量,并计算水、酸溶解度.结果表明,大气TSP中金属的溶出是一个快速过程,仅需几分钟就达到溶解度最大值.Co、Cr和Cd的可溶含量较低,V、Ni、Cu处于中间,Fe、Al、Zn、Mn和Mg较高.结合大气后向轨迹分析,金属可溶含量受到气团来源的显著影响.多种金属的水、酸溶解度差异性较大,Fe水溶解度最小仅为2.0%,其次为Al、Cr、V、Pb、Co、Ni、Cu、Cd、Mn、Mg和Zn.金属溶解度随溶剂p H值的减小而增大.元素本身性质是影响金属溶解度的内在原因,且金属的离子势与水溶解度呈一定的负相关性.     

受引黄影响的河流沉积物细菌群落季节变化

河流沉积物细菌群落的季节变化对碳、氮循环和水环境演化有明显的影响.然而,受调水干预的河流沉积物细菌群落季节性变化尚不明确.本文基于16S rRNA高通量测序技术,研究了中纬度地区受引黄影响的汾河上游沉积物细菌群落组成、结构和多样性的季节变化.结果表明,在引黄调水干预下受水河流细菌群落的季节性变化仍然显著.夏季温度适宜,河流沉积物细菌群落多样性较冬季高.核心菌群组成和结构随季节变化,然而丛毛单胞菌、黄杆菌、黄单胞菌和红环菌等的优势地位不随季节改变.河水水温和ORP的季节变化显著,是造成河流沉积物细菌群落季节变化的主导因子.水质较差的黄河水引入汾河后导致沉积物细菌群落多样性显著提高.引水对河流沉积物细菌群落的影响在夏季较冬季高20%左右.引黄调水对汾河沉积物细菌群落的影响大于季节变化的影响.     

基于交通流的成都市高分辨率机动车排放清单建立

提出一种基于交通流监测数据的道路机动车高分辨率排放清单建立方法,对成都市道路交通流特征进行分析并建立了成都市机动车尾气高分辨率排放清单.结果表明,成都市道路车流量及排放均呈现明显的\"双峰\"分布,早晚高峰时段机动车通行量占全天的39.85%,车队结构中排放标准以国Ⅳ车为主,车辆类型以小型车为主,燃料类型以汽油车为主;道路机动车SO₂、NO_x、CO、PM₁₀、PM_2.5、BC、OC和VOCs(不含驻车蒸发)日排放量分别为3.89、 162.08、 324.11、 4.79、 4.36、 1.89、 0.78和44.37 t,空间分布整体呈现从城市中心到外围排放强度逐渐降低趋势,时间分布基本呈现\"双峰\"分布,颗粒物相关指标受货车流量影响较大; NO_x、PM₁₀、PM_2.5、BC和OC主要来源为大型柴油车,CO主要来源为小型汽油车,其中大型车对NO_x的贡献率达80%;基于保有量的计算方法对成都市道路机动车污染物排放存在一...     

降雨时间分辨率对SWAT水文模拟的影响

分别基于13个雨量站的日降雨量和小时降雨量,在率水流域建立SWAT（Soil and Water Assessment Tool）水文模型,对基于不同降雨时间分辨率的SWAT模型进行独立的参数率定和验证,在此基础上分析降雨时间分辨率对率水流域SWAT模拟性能的影响.结果表明,降雨输入的时间分辨率对率水流域SWAT模型的水文模拟性能有显著影响.小时降雨输入SWAT模型的纳什系数（NSE）和决定系数（R²）在率定期分别为0.89、0.90,在验证期分别为0.86、0.88,均显著高于日降雨输入SWAT模型对应的模型评价统计量值.究其原因,小时降雨输入SWAT模型对于峰值流量的模拟要明显优于日降雨输入SWAT模型.建议应在不同气候与自然环境条件的流域内开展类似的降雨时间分辨率对水文模型模拟性能的影响研究.     

上海金桥出口加工区引进CGS的优化评价

以燃煤锅炉集中供热的上海金桥出口加工区引进天然气热电联供系统（CGS）为例，对其成本和效率作了评价。开发了1个最优化模型，它由季节小时平均热电供需平衡的制约条件和CGS设备容量的目标函数所组成。利用该模型能够在燃料价格和CGS投资费用变化的情况下，便捷地评价最佳的设备容量。引进CGS使氧化硫和二氧化碳排放降低，本模型也能对此作定量评估。     

Incidence of fetal chromosome abnormalities in 2264 low-risk women

Among a population of 6305 pregnant women, aged 25 to 34 years and estimated to be at no increased risk of genetic disease in the fetus, 4606 women participated in a randomized controlled trial of genetic amniocentesis between 1980 and 1984. In the study group having amniocentesis (2264 women), 23 fetal chromosome abnormalities (1.0 per cent) were found: eight autosomal aneuploidies, seven sex chromosome aneuploidies, seven balanced structural rearrangements and one case of a marker some. The structural rearrangements and the marker chromosome were all shown to be inherited. The study group seemed representative for the whole population of younger women at low genetic risk. Therefore, a 1.0 per cent total rate of fetal chromosome abnormalities, consisting of one-third autosomal aneuploidies, one-third sex chromosome aneuploidies and one-third structural rearrangements, may be expected in the second trimester in younger low-risk women. In the same period of time, 562 women in the same age group were offered amniocentesis because of an estimated increased risk of fetal genetic disease. The total rate of fetal chromosome abnormality in this ‘high-risk’ group was 0.9 per cent and thus no different from the rate in the low-risk group.     

分离度对色谱定量分析的影响

介绍了分离度对色谱定量分析的影响，并以水中苯系物的检测为例，验证了采用峰高测量法代替峰面积测量法。可以消除数据处理机对色谱重叠峰处理时造成的偏差，得到满意结果。     

Multivariate curve resolution of multidimensional excitation-emission quenching matrices of a Laurentian soil fulvic acid

Fluorescence excitation–emission matrices (EEM) of aqueous solutions of Laurentian soil fulvic acid (LFA) at three concentrations (50, 75 and 100 mg/l) were obtained at two pH values (pH = 4.0 and 6.0) and as function of the Cu(II) ion concentration. The presence of Cu(II) ion provokes quenching of the intrinsic LFA fluorescence due to complex formation. Multivariate curve resolution (MCR-ALS) was used to successfully decompose single EEM into excitation and emission spectra for the detected components. Moreover, multidimensional (up to six dimensions) data matrices were generated by adding EEM collected as function of the LFA and Cu(II) concentrations and pH. MCR-ALS was able to resolve the excitation and emission spectra from these multidimensional data matrices given further information about the spectral variation profiles induced by the experimental factors. Conditional stability constants (log K_LFACu) were calculated from the quenching profiles observed as function of the Cu(II) concentration, as well as, their trends as function of pH and LFA concentration were obtained – average (and standard deviation) of log K_LFACu = 4.6 ± 0.2. This EEM/MCR-ALS methodology constitutes a new tool for the study of natural organic matter under varying experimental conditions that characterize natural environmental systems.     

Study of dry ice formation during blowdown of CO₂-CH₄ from cryogenic distillation column

Cryogenic distillation columns are generally subjected to high-pressure loadings during the natural gas purification process. The high-pressure conditions inside the column cause safety risk e.g. rupture. When an emergency arises, blowdown is a typical way of minimizing the failure hazard. However, blowdown at the cryogenic conditions involves dry ice formation due to the rapid decrease in temperature driven by the Joule-Thomson effect. The dry ice formation intensifies the failure hazard due to the orifice blockage. Therefore, optimization of blowdown parameters is necessary to avoid the dry ice formation. So far, very limited studies are available in the literature for the blowdown of CO₂-CH₄ mixture, especially at the cryogenic conditions. In this study, a computational investigation followed by the experimental validation is accomplished to analyze the dry ice formation during blowdown of CO₂-CH₄ binary mixture from the cryogenic distillation column. The composition of mixture, orifice size, and initial conditions inside vessel have a high impact on blowdown path. A 3.00 mm orifice is the most suitable size for the blowdown at cryogenic conditions as it doesn't promote solidification and discharges the inventory quickly. Based on the experimental observation, an empirical correlation is also developed to instantly find out the optimum blowdown parameters.