近红外结合Si-ELM检测食醋品质指标

为了提高近红外光谱技术检测食醋中可溶性无盐固形物含量(SSFSC)的精度和稳定性,提出采用联合区间偏最小二乘(Si-PLS)筛选光谱特征区间,再利用极限学习机(ELM)算法建立非线性回归模型,并对该方法的优越性进行系统比较;试验通过交互验证优化模型相关参数,以预测时的相关系数(Rp)和预测均方根误差(RMSEP)作为模型的评价指标。结果表明,Si-PLS结合ELM算法(Si-ELM)所建模型最佳,预测结果:Rp=0.973 9,RMSEP=1.232g/100mL。说明利用近红外光谱技术可以快速准确检测食醋中的SSF-SC,Si-ELM的应用可以适当提高该预测模型的精度。     

Simultaneous measurement of total acid content and soluble salt-free solids content in Chinese vinegar using near-infrared spectroscopy

Total acid content (TAC) and soluble salt-free solids content (SSFSC) in Chinese vinegar are 2 important indicators in the assessment of its quality. This paper shows the feasibility to determine TAC and SSFSC in Chinese vinegar by near-infrared (NIR) spectroscopy. Synergy interval partial least square (Si-PLS) algorithm was performed to calibrate the regression model. The number of PLS factors and the number of intervals were optimized simultaneously by cross-validation. The performance of the model was evaluated according to root mean square error of prediction (RMSEP) and correlation coefficient (R) in the prediction set. The optimum Si-PLS model for TAC was achieved with RMSEP = 0.264 g/100 mL and R(p) = 0.9655; the optimum Si-PLS model for SSFSC was achieved with RMSEP = 1.93 g/100 mL and R(p) = 0.9302. The overall results demonstrated that NIR spectroscopy combined with Si-PLS could be utilized to determinate TAC and SSFSC in Chinese vinegar, and NIR spectroscopy has a potential to be used in vinegar industry.     

基于“文化+ ”协同创新的皮革工业设计专业创业教育分析

在创新创业愈发倍受重视的形势下,高校针对皮革工业设计专业开展创新创业教育具有十分重要的现实意义。以“文化+”协同创新为视角,分析了皮革工业设计专业创业教育,提出了创新创业教育模式的构建策略:根据学生创业需求设置实习实训基地,积极引进“文化+艺术+科技”教育理念,以实现学生创新创业能力培养;在健全皮革工业设计专业创新创业课程体系的同时,合理配置实践实训资源,采取立体化实践教学方式与创客空间教育模式进行创业教学,并针对创业与就业形势科学组织创业竞赛,以实现创业教育目标。     

响应面法优化银杏果酶菌协同发酵工艺

本文旨在运用响应面法优化银杏果的酶菌协同发酵工艺,以期得到一种抗氧化活性高的银杏发酵粉。通过单因素实验探讨了料液比、复合酶制剂添加量、糖化酶和α-淀粉酶添加质量比、酶解时间、混合发酵剂添加量、植物乳杆菌和酿酒酵母添加质量比、发酵时间对银杏发酵粉可溶蛋白含量和DPPH自由基清除效果的影响;并以DPPH自由基清除率为指标,通过响应面分析对银杏果酶菌协同发酵条件进行优化。结果表明,在复合酶制剂添加总量0.3 g/100 g,酶解2 h,发酵12 h的基础上,银杏果酶菌协同发酵最佳工艺为:料液比1:6 g/mL,糖化酶和α-淀粉酶添加质量比2:1,混合发酵剂添加总量3.12 g/100 g,植物乳杆菌和酿酒酵母添加质量比1:1,测得DPPH自由基清除率为69.7%±1.1%,与模型预测值基本一致。由最佳工艺制得的银杏发酵粉（GFP）与未处理的银杏粉（G）相比,DPPH自由基清除率增加了257.4%;可溶蛋白含量4.47±0.13 g/100 g,增加了330%;黄酮含量0.15±0.01 mg/g,增加了50%;多酚含量2.49±0.04 mg/g,增加了118%;银杏酸含量2.96±0.32 μg/g,脱除率达85.4%。说明酶菌协同发酵能显著（P<0.05）提高银杏果的抗氧化活性,制得的银杏发酵粉中可溶蛋白、黄酮、多酚等抗氧化成分含量显著（P<0.05）增加、有毒成分银杏酸含量显著（P<0.05）降低,为银杏果的精深加工提供物质基础。     

自律协同的智能电网能量管理系统家族:概念、体系架构和示例

能量管理系统(EMS)通过信息流调控能量流,保障电网运行的安全高效,被公认为电网运行的"大脑"。随着智能电网的快速发展,传统集中式EMS已难以满足海量信息处理和快速控制决策的需要,为此提出了自律协同的智能电网EMS家族的概念和分布式架构,涵盖了智能电网源、网、荷三大环节的各部分。家族成员内部实现自律,家族成员之间实现协同。分析了家族成员的共性和个性,介绍了若干EMS家族新成员,例如:风电场EMS、变电站EMS和电动车集群EMS。EMS家族成员之间通过互联协调,形成面向整个电力系统的源—网—荷协同的EMS家族网络,支撑整个智能电网的安全高效运行。介绍了若干EMS家族成员协同的示例,如输—配协同、站—中心协同和风—车协同。     

Mg(OH)2/Al(OH)3/包覆红磷阻燃SEBS/PS共混物

研究了Al(OH)3,Mg(OH)2包覆红磷(10份)对苯乙烯-乙烯-丁烯-苯乙烯嵌段共聚物(SEBS)/聚苯乙烯(PS)阻燃性能的影响.结果表明,Mg(OH)2用量为80份时阻燃级别达V-2,氧指数达到29%,但力学性能较差;AI(OH)3用量为80份时阻燃效果不很理想,但对力学性能影响较小;Mg(OH)2/Al(OH)3/包覆红磷体系中Mg(OH)2用量大于Al(OH)3时综合阻燃效果最好.阻燃体系的热释放速率降低,有效燃烧热出现峰值延后.     

Effect of Short-Range Ordering on the Strength-Ductility Synergy of Fine-Grained Cu-Mn Alloys at Different Temperatures

Uniaxial tensile tests were carried out at room temperature (RT) and 250 °C, respectively, to investigate the effect of short-range ordering (SRO) on the mechanical properties and deformation micromechanism of fine-grained (FG) Cu-Mn alloys with high stacking fault energy. The results show that at RT, with the increase in SRO degree, the strength of FG Cu-Mn alloys is improved without a loss of ductility, and corresponding deformation micromechanism is mainly manifested by a decrease in the size of dislocation cells. In contrast, at a high temperature of 250 °C, the SRO degree becomes violently enhanced with increasing Mn content, and the deformation microstructures thus transform from dislocation cells to planar slip bands and even to deformation twins, significantly enhancing the work hardening capacity of the alloys and thus achieving a better strength-ductility synergy of FG Cu-Mn alloys.     

省煤器鳍片管强化传热的三维数值模拟和场协同原理分析

利用FLUENT软件对省煤器横截面积恒定的4种矩形鳍片管的传热和流动特性进行了三维数值模拟,将数值模拟结果与试验结果进行了比较.并用场协同理论进行了分析.结果表明:Re数在2 000～5 000范围内,5 mm×20 mm矩形鳍片管的换热区域速度场和温度场协同度较高并且流动阻力系数较小,其综合强化传热效果好.     

Numerical investigation and analysis of heat transfer enhancement in channel by longitudinal vortex based on field synergy principle

3-D numerical simulations were presented for laminar flow and heat transfer characteristics in a rectangular channel with vortex generators. The effects of Reynolds number (from 800 to 3 000), the attack angle of vortex generator (from 15° to 90°) and the shape of vortex generator were examined. The numerical results were analyzed based on the field synergy principle. It is found that the inherent mechanism of the heat transfer enhancement by longitudinal vortex can be explained by the field synergy principle, that is, the second flow generated by vortex generators results in the reduction of the intersection angle between the velocity and fluid temperature gradient. The longitudinal vortex improves the field synergy of the large downstream region of longitudinal vortex generator (LVG) and the region near (LVG); however, transverse vortex only improves the synergy of the region near vortex generator. Thus, longitudinal vortex can enhance the integral heat transfer of the flow field, while transverse vortex can only enhance the local heat transfer. The synergy angle decreases with the increase of Reynolds number for the channel with LVG to differ from the result obtained from the plain channel, and the triangle winglet performs better than the rectanglar one under the same surface area condition. __________ Translated from Journal of Xi’an Jiaotong University, 2006, 40(9): 996–1000 [译自: 西安交通大学学报]     

Flow and heat transfer in compact offset strip fin surfaces

Experimental studies of air-side heat transfer and pressure drop characteristics of offset strip fins and flat tube heat exchangers were performed. A series of tests were conducted for 9 heat exchangers with different fin space, fin height, fin strip length and flow length, at a constant tube-side water flow rate of 2.5 m³/h. The characteristics of the heat transfer and pressure drop of different fin space, fin height and fin length were analyzed and compared. The curves of the heat transfer coefficients vs. the pumping power per unit frontal area were then plotted. Moreover, the enhanced heat transfer mechanism of offset strip fins was analyzed using field synergy theory. The results showed that fin length and flow length have more obviously effect on the thermal hydraulic characteristics of offset strip fins. __________ Translated from Journal of Shanghai Jiaotong University, 2007, 41(3): 366–369, 375 [译自: 上海交通大学学报]