鱼油纳米乳的制备及贮藏稳定性研究

采用高压均质法,以乳清分离蛋白(WPI)乳化包埋鱼油制备鱼油纳米乳。采用单因素实验研究了主要因素对包封率和吸光比(SRI)的影响,并以包封率为指标,进行正交实验优化工艺配方。同时以不同压力处理的鱼油纳米乳为对照,分别考察了4、25℃条件下鱼油纳米乳的贮藏稳定性。结果表明:最佳工艺配方为乳清分离蛋白质量浓度25 g/L,鱼油添加量100 g/L,均质压力80 MPa,均质次数4次。采用最佳工艺配方制备的鱼油纳米乳的包封率为96.4%,SRI为0.113。稳定性实验结果表明鱼油经纳米乳包埋可显著提高鱼油氧化稳定性,高压处理有利于提高鱼油纳米乳的稳定性,鱼油纳米乳在4℃的贮藏稳定性高于25℃的贮藏稳定性,80 MPa处理鱼油纳米乳经4、25℃放置30 d乳析指数分别为0、1.4%,鱼油纳米乳经25℃放置60 d后过氧化值及渗漏率分别为4.25 meq/kg、5.89%。     

运用有向联接件知识求解装配序列规划

在分析联接件特征的基础上，提出了有向联接件的概念，建立基于联接件知识的零件表达式；运用有向联接件知识求解装配序列规划，实现了知识推理算法和几何约束推理算法的有机结合，有效地降低了装配规划的计算复杂度，保证规划所得装配序列的合理性和实用性．此外，还建立了装配体的自由空间图，可以解决非单调装配序列规划问题。     

基于规则和爆炸图的装配序列规划

提出局部爆炸图的概念，运用几何干涉规则生成各直角坐标方向的局部爆炸图；在确立各方向的合并顺序后，用合并规则生成各零件的合并约束前元集；并据此进行局部爆炸图合并求解装配序列，实现了规则推理和几何推理算法的紧密结合，有效地避免了装配序列组合爆炸，降低了装配规划的计算复杂度，保证规划所得装配序列的可行性和实用性．     

Performance study of a complex thermal barrier functional coating with an electro-spark deposited burn-resistant layer

It is necessary to develop burn-resistant and thermal barrier complex functional coatings on the titanium alloys surface due to the poor high temperature performance for titanium materials and the problem of "titanium fire" which is easily happened.MTU Aero Engines Gmb H has developed a complex functional coating which has great performance of burn resistant and sealing,the coatings has already been applied on compressor blades and casing for aero-engines and showed great performance.In this study,the complex functional coating which is composed of an electro-spark deposited amorphous Ti_(40)Zr_(25)Ni_3 burn-resistant layer and a high-energy plasma spraying prepared YSZ thermal barrier layer was prepared on titanium alloys surface.Then the heat insulation ability,burn resistant performance and the bonding strength were investigated.The experimental results showed that the interface between the coating and the matrix was typical metallurgical bonded,and the average bonding strength was 36.335 MPa;when the temperature of the flame on the one side of the specimen reached 600 ℃,the average insulated temperature of the coating samples was 70.67 ℃;when the flame temperature was 350 ℃,the titanium samples without the complex functional coatings were burned,while the samples with the coating showed great performance of burn resistant even when the temperature was 750 ℃.This indicates that the new functional coating has good heat-insulating and burn-resistant performance.     

浅谈影响桩基工程成本管理因素

桩基工程主要存在于高层建筑和大型综合体,因其规模大,施工周期较长,导致成本较高,需要综合各种因素进行施工。为确保工程的合理性与科学性,需要对其进行成本管理。桩基工程的成本管理涉及成本计划、成本预测、成本控制、成本核算、成本分析和成本评估等因素。     

基于占空比预测与零极点结合的LCL型逆变器延时补偿方法

LCL型并网逆变器数字控制中延时环节对系统稳定性的影响不可忽略。分析发现,网侧电流数字单环鲁棒性不足,需要采用额外的有源阻尼方法增强阻尼,但传统的数字电容电流反馈有源阻尼方法带来了内环数字延时,使电容电流内环等效虚拟电阻不再保持纯电阻特性,增大了系统保持稳定的难度,因此提出一种预测占空比结合零极点补偿控制延时的方法。通过预测控制算法得到占空比和增加零极点,有效地补偿了系统数字延时,消除了采样计算等产生的一拍延时和零阶保持器产生的半拍延时,使系统在有源阻尼方法下能有效地起到增强阻尼的作用。算法设计简单,系统稳定性加强。仿真和实验验证了所提方法的有效性和可行性。     

自驱动湿热烟气全热回收系统的适用性

燃气燃烧产生的烟气具有温度高、含湿量大的特点,虽然可以采用溴化锂吸收式热泵技术对湿热烟气中的显热和潜热热量进行回收,但仍需要外部驱动热源. 为解决现有吸收式热泵系统的热回收能力与经济性较差的问题,以传统溴化锂吸收式热泵机组为基础,通过与分级式烟气换热器相结合,构建了一种可实现自驱动运行的湿热烟气全热回收系统.建立了系统热力模型和适用性模型,并研究了主要参数对系统热力性能和适用性的影响规律.结果表明:在烟气进口温度为550 ℃、入口含湿量为120 g/kg(a)的条件下,系统最大热回收效率为11.6%,热回收净收益平衡期的极小值为5.2 a;当热回收率、净收益平衡期的预期值分别为10%和5.5 a时,二次水出口温度的适用范围为55 ℃~64 ℃.自驱动系统在烟气进口温度较高、含湿量较低时的节能扩大系数极大值为29.7%,表明此时的自驱动系统相对于直接换热方案的节能效果最为显著.     

The investigation of a compact auto-connected wire-wrapped pulsed transformer

For the power conditioning circuit used to deliver power efficiently from flux compression generator (FCG) to the load with high impedance, an air-cored and wire-wrapped transformer convenient in coaxial connection to the other parts is investigated. To reduce the size and enhance the performance, an auto-connection is adopted. A fast and simple model is used to calculate the electrical parameters of the transformer. To evaluate the high voltage capability, the voltages across turns and the electric field distribution in the transformer are investigated. The calculated and the measured electrical parameters of the transformer show good agreements. And the safe operating voltage is predicted to exceed 500 kV. In the preliminary experiments, the transformer is tested in a power conditioning circuit with a capacitive power supply. It is demonstrated that the output voltage of the transformer reaches -342 kV under the input voltage of -81 kV.     

Separation of Refined Silicon from Al-Si Alloys by Air Pressure Filtration

Metallurgical and Materials Transactions B - The separation of refined silicon from Al-Si alloys through a solvent refining process was studied. Purified silicon particles were separated by air...     

基于K-means++与ELM的短期风电功率预测模型研究

风能的波动性对风电产业的迅速发展带来了巨大挑战,准确可靠的短期风电功率预测对满足电网调度以及降低度电成本具有重要意义。文中提出了一种基于K-means++聚类分析和极限学习机(ELM)的短期风电功率预测方法,同时使用数值天气预报(NWP)数据与SCADA系统的历史监测数据,实现了对未来72小时的短期风电功率预测。首先,通过K-means++聚类算法将NWP数据划分为数量不等的簇,之后,使用ELM对每个簇的数据分别建立NWP数据与SCADA功率数据间的映射模型。完成模型训练后,根据数据与各聚类中心点之间的距离选择最佳预测模型。实验结果表明,与常用的经典模型相比,其预测结果精度更高,具有更高的预测性能。