响应面法优化南极菌Psychrobacter sp.B-3的发酵产糖条件

为对南极菌Psychrobacter sp.B-3产胞外糖的发酵条件进行优化,以温度、pH、不同碳源、不同氮源、不同金属离子及海水配比作为唯一变量进行单因素实验,筛选出对产糖有显著影响的单因素取值范围;在此基础上,利用Plackett-Burman实验设计筛选出影响产多糖的3个主要因素,即酵母粉、陈海水配比和装液量.然后通过Box-Behnken实验设计及响应面分析法进行回归分析,得出了南极菌Psychrobacter sp.B-3发酵条件系统优化的结果为:酵母粉1.1 g/L,陈海水与自来水的配比为2:1,装液量为50％,蛋白胨6.0 g/L,接种量1.5％,培养时间64 h,BaCl20.03 g/L,温度10℃,转速150 r/min,pH为7.0.优化后发酵液中的糖含量由优化前的444 μg/mL提高到624 μg/mL,相比初始糖产量提高了40％.结果表明,响应面法可显著优化南极菌Psychrobacter sp.B-3液体发酵产胞外糖的条件.     

Response Surface Optimization for Removal of Cadmium from Aqueous Solution by Waste Agricultural Biosorbent Psidium guvajava L. Leaf Powder

Response surface methodology (RSM) was applied to study the combined effects of the various parameters namely, pH, biosorbent dosage, cadmium concentration and temperature, and to optimize the process conditions for the maximum removal of cadmium using Psidium guvajava L. leaf powder. In order to obtain the mutual interactions between the variables and to optimize these variables, a 2⁴ full factorial central composite design using RSM was employed. The analysis of variance (ANOVA) of the quadratic model demonstrates that the model was highly significant. The model was statistically tested and verified by experimentation. A maximum cadmium removal of 93.2% was obtained under the following optimum conditions: aqueous cadmium concentration 40.15 mg/L, adsorbent dosage 0.5 g/50 mL solution, pH 5.0, and temperature (35°C). The value of desirability factor obtained was 1.     

江蓠中类菌孢素氨基酸(MAAs)成分分析及提取研究

利用高效液相色谱技术对江蓠(Gracilariaceae)中类菌孢素氨基酸(MAAs)进行了分析,并采用响应面分析法对MAAs物质的提取工艺进行优化研究。根据正交旋转组合试验设计原理,采用四因素五水平的响应面分析法,依据回归分析确定各因素的显著程度及最优工艺条件。结果表明,江蓠中MAAs的主要成分为porphyra-334;提取温度、浸提时间、甲醇浓度及液固比为影响MAAs物质提取的显著因素。通过多元二次回归拟合模型响应面分析,得到最优工艺条件:提取温度48.12℃,液固比34∶1,甲醇浓度25%,浸提时间1.85 h,优化条件下预测提取率为4.943 mg/g;试验值为4.893 mg/g,试验值与预测值吻合较好,响应面回归模型的准确性得到验证。     

地下储层表征的不确定性及科学思维方法

由于地质的复杂性和资料的不完备性,地下储层表现为“灰箱”系统,表征结果存在着不确定性.基于系统论和科学哲学的方法,探讨了地下储层表征中不确定性的成因类型、内涵及解决方案,并论述了地下储层表征过程中所应重视的科学思维方法.地下储层表征中存在两类基本的不确定性类型:①随机不确定性,主要由局部预测整体(如应用多井资料进行井间储层预测)以及第二性资料的非完全映射(如应用地震资料预测储层)所致;②模糊不确定性,主要由储层概念模式认知不足所致.为了使表征结果逼近地质实际,除了正确应用和创新相关理论和方法外,需要具备科学的表征理念和思维,包括总体把握、分级约束,多科一体、地质为核,发散求索、聚焦论证,辩证思维、综合分析;同时,应正确理解和处理宏观与微观、绝对与相对、静态与动态、映射与多解、局部与整体、模糊与置信、确定与随机、个别与一般、复杂与简约、手工与自动等矛盾统一体的关系.     

隧道单层衬砌设计方法研究及应用

目前,在单层衬砌设计中应用较为广泛的是基于挪威法的Q系统支护设计法,但该方法涉及的参数有6个,在施工前及施工过程中测试这些参数经验性较强,准确性不高,而且费用较高;将Q法直接移植到中国的单层衬砌设计困难较大,不适合中国国情。在此背景下,提出以屈服接近度和围岩松动圈支护理论为基础的单层衬砌设计原则和方法,并结合合武铁路大别山隧道2号斜井进行了工程实践。首先通过地质勘查得到隧道所在地区的工程地质、水文地质特征以及围岩的物理力学指标,确定隧道围岩的屈服接近度,进而提出单层衬砌支护参数及喷射混凝土的力学控制指标,完成结构的预设计;根据隧道施工过程中实测的围岩松动圈范围,运用松动圈支护理论修正设计,从而形成一套完整的单层衬砌设计方法体系。实践表明,提出的单层衬砌设计方法经济适用、对施工干扰小,适合信息化施工,且施作完成的单层衬砌结构安全可靠,具有显著的经济效益和社会效益,有较大的推广前景。     

On a PUB methodology from Chinese lessons

Abstract

Based on a Chinese saying: “Even a clever housewife cannot cook a meal without rice”, a simple categorization of the methods for Predictions in Ungauged Basins (PUB) is proposed, including: Borrowing, obtaining hydrological information by transplanting measurements from a similar basin, or extrapolating/interpolating the data from neighbouring catchments; Substituting, finding substitutes either from the ungauged basin or from donating area(s); and Generating, obtaining data via field or laboratory observations. The Substituting category is classified further into: S1, substitution only from within the ungauged basin using fully process-based models without calibration; S2-1, from similar gauged basins using established index/distribution; S2-2, from various gauged basins using regression and/or process-based relationships between the climate/catchment features and hydrological signatures (CCH), and S3, from the information beyond the CCH relationship. Based on a review, the Darwinian S2-2 and Newtonian S1 were found to be the two most popular methods, both for China and worldwide PUB.

Editor Z.W. Kundzewicz     

Preparation of Nano‐Lepidocrocite and an Investigation of Its Ability to Remove a Metal Complex Dye

Lepidocrocite (γ‐FeOOH) nanoparticles were synthesized from iron(II) sulfate solution and characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform‐IR (FT‐IR), nitrogen adsorption, and point of zero charge pH (pH_PZC) analyses. TEM, XRD, and FT‐IR analyses proved the synthesis of nano‐lepidocrocite. Surface area and pH_PZC of the synthesized lepidocrocite were 68.1 m² g^?1 and 4.8, respectively. Utilization of the synthesized lepidocrocite in the adsorption of Lanacron brown S‐GL (LBS‐GL) from aqueous solutions was investigated, and the effect of lepidocrocite dosage, pH, temperature, and contact time on this process were optimized and modeled using response surface methodology approach. The lepidocrocite dosage of 0.015 g, pH 3.5, temperature of 38°C, and contact time of 100 min were determined as optimum adsorption conditions. Isotherm and kinetics of the adsorption process were analyzed at the optimum conditions. The equilibrium data were fitted well to the Langmuir isotherm model. The maximum monolayer adsorption capacity was 528.21 mg g^?1. The adsorption process was described by the pseudo‐second‐order kinetic model. Furthermore, the effect of pH on the desorption of LBS‐GL was investigated. High LBS‐GL desorption efficiency was achieved at a high pH value.     

Urban Employment Subcenters and Sectoral Clustering in Montreal: Complementary Approaches to the Study of Urban Form

Since the late 1980's there has been renewed interest in the study of employment polynucleation within metropolitan areas, fed in part by the move to suburban locations of high-order service functions. In parallel, a growing body of research has underlined the role which proximity plays in information exchange, innovation and growth. So far there have been only limited attempts to merge these two approaches and investigate the degree to which local agglomeration economies and positive externalities may underpin the creation of suburban employment poles. In this paper a first step is taken in this direction by proposing an approach to systematically investigate the colocation of economic activities within a metropolitan context. It is found that the groups of economic activities which systematically tend to colocate closely mirror those activities which would be grouped together along sectoral lines.