微波辅助提取莲心黄酮类物质工艺参数的优化

为了探讨微波辅助提取莲心中黄酮类物质的工艺条件,研究微波功率、微波提取时间及料液比对莲心黄酮类物质提取效果的影响,通过正交试验设计优化其提取工艺参数。结果表明:影响莲心黄酮类物质提取效果的主次因素顺序为微波提取时间>微波功率>料液比,最佳提取工艺参数为微波功率700W,微波提取时间10min,料液比2:100(g:mL),在此条件下莲心黄酮类物质提取率为1.8725%;与传统水浸提方法相比,该方法可以提高提取率,缩短提取时间。     

辽宁省水稻测土配方施肥相关参数的研究

根据＂3414＂试验结果,初步摸清了水稻相对产量与土壤有效养分,土地依存率与土壤有效养分之间的关系,以及测土值与水稻养分吸收关系,并根据有效养分含量与校正系数的函数关系,建立了水稻土壤有效养分校正系数推算表。     

组合式螺旋板齿种子玉米脱粒机工作参数优化

根据Box-Behnken试验设计原理,以喂入量、脱粒轴转速、板齿螺旋角和排芯口压板压力为自变量,籽粒破碎率为响应值,采用四因素三水平响应面分析方法,并利用Design-Expert软件建立数学模型,对各因素及其交互作用进行分析.建立了各因素与籽粒破碎率之间的数学模型.试验数据分析表明:建立的回归方程显著;4个因素对籽粒破碎率影响的主次顺序为板齿螺旋角、脱粒轴转速、喂入量和排芯口压板压力;最佳工作参数为:喂入量2.8 kg/s、脱粒轴转速241 r/min、板齿螺旋角9°和排芯口压板压力40 N,此时籽粒破碎率为0.366％,较参数优化前的破碎率减小了0.084％ ～0.274％.     

水稻抛秧机秧苗运动分析及参数确定

通过对旋转锥盘式水稻抛秧机秧苗在锥盘上的运动分析和受力分析,建立了秧苗在锥盘上的运动轨迹方程,分析了秧苗抛出后的运动轨迹及影响抛秧性能的主要参数,通过计算确定一级最佳工作参数,为旋转锥盘式水稻抛秧机设计提供了理论依据。     

打穴播种机结构参数和工作参数的优化设计

对于不同的玉米种子,以重播率最小为目标对铲式玉米精密播种机的垂直倾角β、水平倾角γ及播种速度υ三个参数进行了计算机辅助优化设计。根据优化计算结果,设计了铲式玉米精密播种拖肥机。     

参数不确定度对汽车侧面碰撞事故再现结果的影响

基于不确定度理论,研究了汽车侧面碰撞交通事故再现分析所需参数的不确定度,包括汽车的载质量、碰撞后质心位移和路面摩擦因数。将测量所得现场几何参数的不确定度视为微小不确定度忽略不计,只考虑路面摩擦因数引进的二阶不确定度及质量参数的影响,针对碰撞前速度的基本算法建立了相应的不确定度分析方法,并给出了应用实例,分析了上述两种参数取值的不确定度对计算结果的影响。     

Parameters causing variation between soil screening values and the effect of harmonization

Background, aim, and scope

This paper discusses the variation between generic soil screening values (SSV) from 17 countries for 11 volatile organic contaminants (VOC). The variation between SSV was one to four orders-of-magnitude (OOM) depending on the SSV and landuse type. What would be the variation if parameter values are harmonized between member states?

Main Features

The effect of harmonization was visualized by firstly reviewing the technical derivation procedure for SSV for 7 SSV from five countries and collecting all parameter values that are involved in the deviation. The parameters were subdivided in scientific (e.g. algorithm plus its parameter values), political (e.g. toxicological reference) or geographical (e.g. building and soil properties) elements. Secondly, new SSV were calculated with progressively harmonized sets of scientific and/or political parameter values, while the geographical parameters varied. Thirdly, the variation between SSV was compared before and after harmonization.

Results

Results show that harmonizing algorithms plus other scientific and political parameters are suited for harmonization. The variation decreases to 1 OOM, after scientific and political parameters were harmonized. Geographical parameters seem to have less impact on the differences between SSV.

Discussion

So, should we harmonize the procedures for deriving SSV between EU member states? The need for discussing harmonization is also raised by the upcoming EU Soil Framework Directive.

Conclusions

Clearly common generic SSV across all of Europe are not appropriate, since countries are allowed to include member state specific geographical and cultural elements and also political decision making. By harmonizing scientific and/or political parameters differences between SSV can be made more transparent between member states and it will encourage convergence in procedures among member states to ensure neutral conditions of competition and a coherent soil protection regime throughout Europe.

Recommendations and perspectives

To promote uniformity it is recommended to construct a toolbox for the calculation of human health risk exposure, carried by a European consensus, that includes different model algorithms for which fixed and flexible input parameters are made available. Fixed algorithm parameters are standardized and applied uniformly by all member states, e.g. physico-chemical parameters, while flexible input parameters permits member states to include region or country specific parameter values and policy decisions.     

基于支持向量回归机的粮食产量预测研究

支持向量机(Support Vector Machines,SVM)是一种具有坚实理论基础的新颖小样本学习方法。采用支持向量机回归(Support Vector Machine Regression,SVR)算法,用libsvm-2.89软件包对我国近年来的粮食产量进行回归预测,选择交叉验证法进行参数寻优,建立粮食产量和其影响因素的支持向量机回归模型。粮食产量预测平均相对百分误差为1.209%,均方根误差为581.191,相关系数为0.962 24。将预测结果与指数平滑模型、生产函数模型及多元线性回归模型进行了比较,用平均绝对百分误差、希尔不等系数及均方根误差对4种模型预测结果进行评价。结果表明,基于支持向量机的径向基核函数(RBF)模型预测粮食产量的精度优于其他预测方法。     

好氧发酵过程中臭气产排和原位控制技术研究进展

好氧发酵过程产生大量无机和有机挥发性物质,其中无机物NH₃、H₂S和部分挥发性有机物是主要恶臭物质,不仅污染环境且危害人体健康。结合国内外研究现状,本研究总结好氧发酵过程臭气的产生机理及影响因素,重点分析不同或相同原料产生臭气种类,同时结合VOCs排放标准及部分恶臭嗅阈值,提出好氧发酵应重点关注苯系类和含硫化合物这两类物质;比较分析了优化工艺参数和原位除臭添加剂对臭气产排控制效果和机制,今后应重点关注VOCs原位控制技术方面的应用研究及高效复合除臭剂研发,为好氧发酵臭气减排提供理论依据。     

鸭蛋腌制过程中某些成分变化规律的研究

本文对鸭蛋腌制过程中pH值、含水量及蛋黄油量和游离脂肪酸含量的变化规律进行了初步研究。结果表明,除游离脂肪酸外,pH值、含水量、蛋黄油量有很大变化。其中,pH值、含水量下降,蛋黄油量增高。