乙酰胆碱酯酶试剂包配方的选择

以商品化乙酰胆碱酯酶试剂包为研究对象,比较了不同用量的乙酰胆碱酯酶、底物和显色剂下的抑制率,并在此基础上进行了正交试验,在保证一定的检测精度前提下最终确定了酶用量为原来的3/4,底物用量为原来的3/4,显色剂用量为原来的1/2,降低了检测成本。通过F检验证明,调整后配方与原配方之间无显著性差异。在此条件下,氧乐果、敌百虫、敌敌畏的检出下限大约分别为0.37mg/L、0.09mg/L、0.035mg/L,与原配方一致。     

Stability analysis on shallow tunnel with floor lift under inclined ground by upper bound method

采用极限分析上限法,基于内外能耗守恒原理,通过构建考虑隧底隆起的斜坡地段浅埋隧道破坏模式,推导出围岩压力的计算式,并通过典型算例重点分析了典型因素对隧道围岩稳定性的影响。研究结果表明：基于泰沙基极限平衡法进行隧道围岩支护设计较为保守,不考虑隧底隆起的极限分析方法次之考虑隧底隆起极限分析方法的风险最大;斜坡地表倾角增大对浅埋隧道稳定性有着不可忽视的不利影响;围岩压力随岩土侧压力系数减小、埋深增大、断面尺寸加大而增大;岩土黏聚力增大、内摩擦角增大对提高浅埋隧道围岩稳定性有积极作用。     

THE THEOREM OF STATIONARY VALUE OF WEIGHTED ENERGY AND ITS WEIGHTING FUNCTIONS

This paper presents two energy functionals which are made as stationary values. Thus, the theorem of stationary value of weighted generalized potential energy and the theorem of stationary value of weighted generalized complementary energy are established. In the first theorem, the stress boundary weighting function must be equal to the internal weighting function while the displacement boundary weighting function is independen; and in the (?)econd theorem, the displacement boundary weighting function must be equal to the internal weighting function while the stress boundary weighting function is independent.     

改进Hargreaves模型估算川中丘陵区参考作物蒸散量

为提高Hargreaves-Samani(HS)模型参考作物蒸散量(ET0)计算精度,该文基于贝叶斯原理利用川中丘陵区1954-2002年逐日资料对其温度指数、温度系数和温度常数进行改进,并使用2003-2013年资料以Penman-Monteith(PM)模型为标准评价HS改进模型计算精度与适应性。结果表明:HS改进模型参数在川中丘陵区各区均小于联合国粮农组织推荐值,并呈现出随纬度上升而增大的趋势;与PM模型计算结果相比,HS改进模型计算的ET0相对误差在川中丘陵区北部从14.2%~60.9%降至-1.1%~33.4%、中部从40.6%~92.6%降至16.9%~61.1%、南部从31.3%~96.0%降至8.5%~64.4%、整个川中丘陵区从32.1%~82.7%降至9.5%~52.6%;相关性分析表明,HS改进模型和PM模型计算的ET0回归曲线的斜率更接近于1(北部1.16、中部1.02、南部0.99、全区1.13),决定系数均达到0.85(P0.01)以上;趋势分析表明,HS改进模型和PM模型计算的ET0变化一致,年内均呈开口向下的抛物线状,年际均呈微小上升趋势。因此,基于贝叶斯原理改进的HS模型在川中丘陵区不同区域变异性较小,适应性较强,具有较高的计算精度,可作为川中丘陵区参考作物蒸散量简化计算的推荐模型。     

Measuring and predicting soil moisture conditions for trafficability

ABSTRACT

The main cause of loss of soil structural stability is vehicle operation on unpaved wet surfaces. Unfortunately, there is a lack of continuous soil moisture data in predicting trafficable conditions. To measure changes in soil moisture conditions in real time, Percostation (Adek) sensors were installed in sandy loam Stagnosol soil at different depths. Problems with soil trafficability can be expected at the plastic limit, and the soil is unable to support vehicle operations at the liquid limit in such soils. The maximum water-holding capacity of the soil is 32%, the field capacity is 25%, the plastic limit is 22%, and the liquid limit is 30%. With rainfall of more than 10?mm d^?1, the moisture content reached the plastic limit in the upper 25?cm of soil. The average increase in the soil moisture content after more than 10?mm of rain was 1–2.5% in a time frame of 2–3 hours. After rain, the previous soil moisture level was obtained within 2 to 3 days in the vegetation period. Measurements also allowed soil water balance and evapotranspiration modelling data to predict soil moisture conditions with an accuracy of one day but failed to predict in a shorter period.     

桉木单板层积材生产工艺的优化

采用响应面法(RSM)和中心组合旋转设计(CCRD),研究了桉树单板层积材(LVL)的生产工艺条件,并对优化工艺所得的预测值进行了实验验证。方差分析结果表明:面粉添加量对桉木LVL的静曲强度(MOR)和弹性模量(MOE)有着显著影响,而热压温度和热压时间的影响不显著。通过回归分析,建立了相应的回归模型。回归模型的预测值与实验值的拟合良好,说明回归方程能用来预测和优化桉木LVL的力学强度性能。最佳工艺条件为:热压温度130℃,热压时间1.5 min/mm,面粉添加量5%(质量分数)。在此工艺条件下压制的桉木LVL垂直加载条件下的静曲强度(MOR⊥)和弹性模量(MOE⊥)分别为89 MPa和16 722 MPa,平行加载条件下的静曲强度(MOR∥)和弹性模量(MOE∥)分别为88 MPa和15 067 MPa,MOR和MOE分别达到了结构用单板层积材国家标准的优等品和140E级别。     

高效液相色谱法和光度法测定苯酚的对比

分别对液相色谱法和4-氨基安替比林分光光度法,测定苯酚的精密度、检测限及准确度等,进行对比和分析.结果表明:色谱法和光度法精密度和准确度均较高,但光度法操作简便且检出限较低,费用少,建议作为酚醛胶木制品苯酚释放的定量方法.     

中原地区丹红杨插干造林技术研究

丹红杨是中国林业科学研究院2003年培育成功的新一代超速生抗虫杨,雌株。耐桑天牛、易生根、速生（年胸径生长量达5.8 cm,年平均高生长量4.9 m）。为了提高丹红杨的造林成活率,进行了杨树插干深栽造林试验。试验结果表明,丹红杨采用插干深栽造林方法与传统的带根植苗造林相比,具有成本低、成活率高、生长量大等特点,是一种比...     

AB-DTPA浸提法研究上海中心城区绿地土壤有效态养分特征

采用AB-DTPA浸提剂联合电感耦合等离子体发射光谱法研究上海9个中心城区的509个绿地土壤的10种有效态养分含量。结果表明:上海中心城区绿地土壤有效态钾、钙、镁、锰和铁含量丰富;有效态磷、硫和钼普遍缺乏,部分土样有效磷、硫的含量超标与大量施用有机改良材料有关;有效态锌和铜均发生不同程度的累积,有些土样超标。不同时空的绿地土壤有效态养分含量与成土因素和人为活动有关。随着绿地建成年限延长,土壤有效锌和有效铜含量显著增加,但其他养分变化不显著。就上海不同区域而言,杨浦区、闸北区、浦东新区和徐汇区有效态养分含量相对较低;长宁区、静安区和黄浦区有效态养分含量较高;虹口区和杨浦区锌、铜累积程度高。公共绿地与公园土壤养分含量相当;道路绿地的有效态钾、硫、镁显著高于前两者,但有效态锌、铜和铁含量显著低于前两者。随着土壤剖面加深,土壤有效态硫、镁和钼含量呈增加趋势,而有效态磷、钾、锰、锌含量稍许降低。AB-DTPA浸提法适用于土壤中大部分有效态养分的快速分析,建议在全国推广应用。