熵权多目标决策法在水资源系统决策分析中的应用

义乌市是一个水资源紧缺的城市,随着义乌经济的快速发展,仅靠义乌市北部水资源(八都水库等)是满足不了义乌经济发展对水的需求.2003年的干旱,义乌城区用水紧张,从2003年11月起限时降压供水.按照义乌市总体规划,向东阳横锦水库购买5 000万m3/a的水,也只能维持到义乌市规划中期,远期还将缺水8 700万m3/a,从而提出义乌市分质供水系统的可研方案.应用熵权多目标决策法,对义乌市水资源规划进行量化分析,为更进一步地开发利用义乌水资源,提供科学地决策依据.     

Capsaicinoids quantification in chili peppers cultivated in the state of Yucatan,Mexico

Capsaicinoids are a group of 12 or more related alkaloids responsible of the pungent sensation in fruits of the genus Capsicum. Capsaicin [(E)-N-(4-hydroxy-3-methoxybenzyl)-8-methyl-6-nonenamide] and dihydrocapsaicin are responsible for more than 90% of the pungency. This work describes the quantitative analyses by gas chromatography of the content of capsaicin and dihydrocapsaicin in the pericarp, placenta, and seeds of seven cultivars of chili peppers cultivated in the state of Yucatan, Mexico [chawa, dulce, sukurre, xcat’ik (Capsicum annuum L. var. annuum), maax (Capsicum annuum L. var. aviculare), and habanero orange and habanero white (Capsicum chinense Jacq.)]. Capsaicin content was higher, as expected, in the fruits of habanero orange and habanero white, followed by sukurre, chawa, xkat’ik, and maax. Dihydrocapsaicin content did not follow the same scheme, being higher in the fruits of sukurre, followed by chawa, habanero white, habanero orange, and maax. Xcat’ik showed minor quantities of dihydrocapsaicin, while dulce chili contained only traces of these two alkaloids.     

上海区域常见园林树种树高尺度定量预估及林冠线营造探析

树高及树木垂直生长空间对于群落外貌(如林冠线的营造)以及复层结构的构建起到关键作用。本文以上海地区城镇绿化较为常见的23种园林树种为研究对象,对不同胸径梯度下(分别设置为10cm、16cm、22cm、28cm)的树高尺度进行调查与测定。基于所选取及调查树木样本的实测数据,对胸径—树高两者之间的关系进行回归拟合,将所涉及园林树木树高尺度划分为4种伸展类型,并讨论了树高尺度在种植设计中的应用。最后,尝试通过从冠顶角与冠重叠2个方面对林冠线进行定量化解析,以期为群落垂直结构的配置及林冠线的营造提供参考依据。     

Parameter estimation and prediction uncertainties for multi-response kinetic models with uncertain inputs

Error-in-variables model (EVM) methods are used for parameter estimation when independent variables are uncertain. During EVM parameter estimation, output measurement variances are required as weighting factors in the objective function. These variances can be estimated based on data from replicate experiments. However, conducting replicates is complicated when independent variables are uncertain. Instead, pseudo-replicate runs may be performed where the target values of inputs for repeated runs are the same, but the true input values may be different. Here, we propose a method to estimate output-measurement variances for use in multivariate EVM estimation problems, based on pseudo-replicate data. We also propose a bootstrap technique for quantifying uncertainties in resulting parameter estimates and model predictions. The methods are illustrated using a case study involving n-hexane hydroisomerization in a well-mixed reactor. Case-study results reveal that assumptions about input uncertainties can have important influences on parameter estimates, model predictions and their confidence intervals.     

GC–MS analysis of oxysterols and their formation in cultivated liver cells (HepG2)

Oxysterols play a key role in many (patho)physiological processes and they are potential biomarkers for oxidative stress in several diseases. Here we developed a rapid gas chromatographic-mass spectrometry-based method for the separation and quantification of 11 biologically relevant oxysterols bearing hydroxy, epoxy, and dihydroxy groups. Efficient chromatographic separation (resolution ≥ 1.9) was achieved using a medium polarity 35%-diphenyl/65%-dimethyl polysiloxane stationary phase material (30 m × 0.25 mm inner diameter and 0.25 μm film thickness). Based on thorough analysis of the fragmentation during electron ionization we developed a strategy to deduce structural information of the oxysterols. Optimized sample preparation includes (i) extraction with a mixture of n-hexane/iso-propanol, (ii) removal of cholesterol by solid phase extraction with unmodified silica, and (iii) trimethylsilylation. The method was successfully applied on the analysis of brain samples, showing consistent results with previous studies and a good intra- and interday precision of ≤20%. Finally, we used the method for the investigation of oxysterol formation during oxidative stress in HepG2 cells. Incubation with tert-butyl hydroperoxide led to a massive increase in free radical formed oxysterols (7-keto-chol > 7β-OH-chol >> 7α-OH-chol), while 24 h incubation with the glutathione peroxidase 4 inhibitor RSL3 showed no increase in oxidative stress based on the oxysterol pattern. Overall, the new method described here enables the robust analysis of a biologically meaningful pattern of oxysterols with high sensitivity and precision allowing us to gain new insights in the biological formation and role of oxysterols.     

Quantification of significant volatile components of pacharán

 Pacharán is a traditional drink from Navarra (Spain). This liqueur is obtained by maceration of sloe berries (Prunus spinosa L.) with aqueous ethanol and subsequent addition of sugar and essential oils of anise (Pimpinella anisum L. or Illicium verum H.). The following volatile components of pacharán were identified and quantified: cis-anethol; trans-anethol; anisaldehyde; benzaldehyde; benzyl alcohol; γ-butyrolactone; 1,1-diethoxyethane; ethyl benzoate; ethyl lactate; diethyl malate (hydroxybutanedioic acid diethyl ester); estragol (methyl chavicol); eugenol [2-methoxy-4-(2-propenyl)-phenol]; 2-furaldehyde; linalool; cis-3-hexen-1-ol; (4-methoxyphenyl)propanone; 2-phenylethanol and vanillin. Received: 3 November 1997 / Revised version: 29 December 1997     

我国传统粮食科学技术的量化考察与分析

本文对我国古代粮食科学技术分别从粮食储藏、粮食加工、食品加工和造曲酿酒等四方面进行了量化考察，并作了综合分析，确认量化程度由高到低的序列为：造曲酿酒——食品加工——粮食加工——粮食储藏。在量化考察分析的基础上，得出古代粮食科学技术在发展中的重要教训是，在已取得辉煌成就的基础上，没有从“数量化”的高度进行归纳总结，因而没有得出有意义的结论，使得已有的科学技术成就无法突破并继续提高。文章最后指出了古代粮食科学技术未能实现数学化的三条主要原因。     

红莓果中花青素的提取工艺研究

以HCl-乙醇为溶剂,研究了红莓果中花青素的最佳提取工艺。在单因素试验中,选择了单次提取和2次提取,分别测定了不同提取级数下各因素(物料比、提取时间、提取温度)的最佳水平值。同时,以果实中花色苷的绝对含量作为提取效率的评价标准,提高了单纯采用吸光度值测定法作为评定指标的精确性与可靠性。通过响应面试验确定了最佳的提取工艺参数为:浓度为1.5 mol/L的HCl和体积分数95%的乙醇(体积比15∶85)为溶剂,提取料液比为5 g∶1 mL,提取时间为53 min,提取温度为71℃,提取2次。依此工艺,红莓花青素的提取得率为36.39 mg/100 g(鲜果)。     

The mineral phase quantification of vermiculite and interstratified clay minerals-containing ores by X-ray diffraction and Rietveld method after K cation exchange

Hydrothermal transformations and weathering are important mineralizing processes in carbonatite-related ores. But the transformation products of mafic minerals, such as the clay minerals, vermiculite and interstratified phases, preclude the use of X-ray diffraction, particularly the Rietveld method, for mineral phase quantification. After treatment with KCl, vermiculite and interstratified phases (all peaks roughly at 1.2, 1.4-1.5 and 2.4 nm) are converted to a phlogopite-like structure with d(0 0 1) = 1.0 nm, which can successfully be refined. The method was tested using three carbonatite-derived ores, with a total phlogopite-like phase content ranging from 1.2 to 32.3 wt.%. Comparison of the chemical analyses with the calculated chemical composition, based on the phase quantification and the mineral composition is in good agreement for major elements, such as Si, Fe and Al. For P results were also very good, but Ti and Nb are generally underestimated, and Ba is overestimated. Minerals with lower contents, as pyrochlore, approach the diffraction detection limit. Problems to accurately determine mineral composition for some of the phases also impacts on the reconciliation. The chemical composition of the pyrochlore group minerals changed, but not to an extent to constrain the usefulness of the technique. Cation exchange successfully extended the amenability of the Rietveld method for phase quantification.