复合保鲜剂结合MAP对鲜切茄子贮藏品质的影响

为延长鲜切茄子的保鲜时间,研究单一气调包装(2%CO2+5%O2+93%N2)和保鲜液(1.5%壳聚糖+1%抗坏血酸+1%氯化钙+2%柠檬酸)结合气调包装对鲜切茄子品质的影响。以感官评分、褐变度、硬度、多酚氧化酶(PPO)活性和细菌总数为指标,分析鲜切茄子于(10±1)℃下贮藏8d内的品质变化。结果表明:贮藏8d后,对照组样品的L*值、硬度、PPO酶活性和细菌总数分别为75.66、7.41kg/cm2、68.77U/(min·g)和5.52lg CFU/g,而经保鲜液结合气调包装的鲜切茄子各指标分别为82.51、10.05kg/cm2、23.70U/(min·g)和2.87lg CFU/g。气调包装能够抑制鲜切茄子的褐变、萎蔫等感官品质的下降,并抑制PPO活性的增加和细菌的生长繁殖,尤其在结合保鲜液处理后效果更加明显,贮藏8d仍保持较好的品质。     

(3+1)维修正KdV-Zakharov-Kuznetsov方程的行波解

结合动力系统分支理论,对一个非线性(3+1)维修正KdV-Zakharov-Kuznetsov方程进行理论上的研究.首先,根据不同参数值和三次方程判别式分别定性分析了平衡点的类型和相应轨线情况.其次,利用Ja-cobi椭圆函数,从形式上给出了若干有界行波解和同宿轨的公式,这一结论扩展了已有文献的工作.最后,利用Hami...     

基于随机森林算法的改性水润滑轴承摩擦性能预测*

为验证随机森林算法在预测改性水润滑轴承摩擦学性能上的可行性,利用Python编写算法,并通过已知实验数据进行仿真建模。通过已知数据对算法的准确性进行验证,其接受者操作特征（ROC）曲线的均值为0.85,证明模型的准确性较高。在不同温度及载荷工况条件下通过实验对预测模型进行验证,实验结果与预测结果间的误差均在5%左右,表明构建的随机森林模型可以用于改性水润滑轴承的摩擦学性能预测。研究结果表明：温度对于该改性水润滑轴承的平均摩擦因数有较大的影响,而负载对平均摩擦因数的影响较小,但是对于轴承的运转稳定性影响较大。     

改性膨润土防渗浆材的性能研究

以聚乙烯醇为改性剂制得有机化膨润土,并与水泥、粉煤灰及辅助添加剂组成防渗浆材,通过正交试验法,分析了浆材固结体的渗透性、吸附阻滞性和耐久性。结果表明,以改性膨润土代替天然膨润土获得的浆材具有更低的渗透系数、更好的吸附阻滞性及耐腐蚀性,完全满足抗渗要求。     

Unsteady nanofluid flow between two spinning expanding disks with continuous vertical motion under the influence of modified Hall effect

The principle aim of this article is to detect the effects of externally applied magnetic force in the nanofluid flow, flowing between two co-axially rotating and expanding disks where the upper disk is continuously moving vertically upward and downward. Also, the modified Hall Effect has been considered as an effective factor of the flow. The lower disk is vertically static. The rotation and vertical motion of the disks create a three-dimensional flow of nanofluid. Heat and mass density along with the motion of the flow has been analyzed under the variation in magnetic and Hall parameters. The findings have been compared with the results in Von Karman flow of nanofluid between two rotating and stretching disks. The velocity components have been largely influenced by magnetic and Hall parameters in case of downward movement of the upper disk. The fluid temperature is detected higher in case of upward velocity and lower in case of the downward motion of the upper disk. The heat transferability of the disks is effected differently at two different disks with the influence of magnetic force and Hall effect.     

基于多维缩放的日负荷曲线聚类分析

负荷曲线聚类在负荷预测,需求侧响应等方面有重要应用。目前负荷数据日趋海量化和多维化,需要对其进行降维处理,但现有的降维会对曲线信息造成一定程度的损失,为此提出了一种基于多维缩放(Multi-Dimensional Scaling,MDS)降维的日负荷曲线聚类方法。首先使用MDS算法对采集到的负荷数据进行降维处理,然后采用CRITIC—熵权法作为降维指标的权重配置方法,最后通过计及权重的修正轮廓系数选择最优类簇数,以加权欧式距离的K-means算法进行聚类。通过算例表明该方法能最大程度保留原始曲线信息,在聚类准确度和运行时间两方面均有优势。     

改进粒子群算法在梯级水库优化调度中的应用

针对粒子群优化算法搜索精度不高和易陷入局部最优解的缺陷,结合梯级水库联合优化调度的实际问题,提出了惯性权重的余弦处理机制和自适应选择学习对象策略,并结合分层交叉思想对粒子群算法进行了改进。实例计算表明:该算法合理、可靠,有效地提高了计算精度与效率。     

改质沥青粘结剂添加环氧树脂对铝电解用炭间糊性能的影响

以电煅煤、沥青焦、熟碎为骨料,改质沥青、环氧树脂为粘结剂制备铝电解用炭间糊,采用电阻率测试仪、万能试验机、捣固糊收缩测试仪、扫描电镜及同步热分析仪等设备对其性能进行表征,并与目前工业上广泛应用的炭间糊进行比较。结果表明,随着环氧树脂含量的增加,制备糊料的捣固温度逐渐降低,理化性能有所下降,失重速率增加,显微结构由无序层片状逐渐向有序纤维状转变。当环氧树脂添加量为50%时,制备炭问糊可在室温(15²5℃)捣固施工,同时具备较佳的综合性能。     

Electrocatalytic and simultaneous determination of isoproterenol, uric acid and folic acid at molybdenum (VI) complex-carbon nanotube paste electrode

This paper describes the development, electrochemical characterization and utilization of a novel modified molybdenum (VI) complex-carbon nanotube paste electrode for the electrocatalytic determination of isoproterenol (IP). The electrochemical profile of the proposed modified electrode was analyzed by cyclic voltammetry (CV) that showed a shift of the oxidation peak potential of IP at 175 mV to less positive value, compared with an unmodified carbon paste electrode. Differential pulse voltammetry (DPV) in 0.1 M phosphate buffer solution (PBS) at pH 7.0 was performed to determine IP in the range from 0.7 to 600.0 μM, with a detection limit of 35.0 nM. Then the modified electrode was used to determine IP in an excess of uric acid (UA) and folic acid (FA) by DPV. Finally, this method was used for the determination of IP in some real samples.     

Second-order data obtained from differential pulse voltammetry: Determination of tryptophan at a gold nanoparticles decorated multiwalled carbon nanotube modified glassy carbon electrode

Three-way data obtained from different pulse heights of differential pulse voltammetry (DPV) was analyzed using multivariate curve resolution by alternating least squares (MCR-ALS) algorithm. Differential pulse voltammograms of tryptophan were recorded at a gold nanoparticles decorated multiwalled carbon nanotube modified glassy carbon electrode (GCE/MWCNTs-nanoAu). The determination of tryptophan was performed even in the presence of unexpected electroactive interference(s). Both the simulated and experimental data were non-bilinear. Therefore a potential shift algorithm was used to correct the observed shift in the data. After correction, the data was augmented and MCR-ALS was applied to the augmented data. A relative error of prediction of less than 8% for the determination of the simulated analyte of interest and tryptophan in synthetic samples indicated that the methodology employing voltammetry and second-order calibration could be applied to complex analytical systems.