动态矩阵控制在电阻炉温度控制系统中的应用

通过对电阻炉动态对象特性的研究以及预测控制方法的改进，比较了动态矩阵控制和PID控制在电阻炉温度控制系统中的应用效果．仿真结果表明：DMC不但克服了建模的不精确性和参数的时变性，而且根据给定的期望曲线，实现了比PID控制更令人满意的性能指标．     

超声波处理对牛乳浓缩蛋白水溶性的影响

经贮藏后的牛乳浓缩蛋白(milk protein concentrate,MPC)的水溶性会下降,而MPC的水溶性直接影响其应用价值.本实验利用超声波技术处理新鲜和贮藏后的MPC,研究不同超声波处理条件对贮藏后的MPC水溶性的影响.结果表明:超声处理(50、300、600 W分别处理5 min; 300 W分别处理3、5、10 min)贮藏后的MPC85,其水溶性显著下降;而超声处理(300 W或600 W分别处理3、5、10 min)新鲜MPC70后在50℃条件下贮藏30 d,其水溶性下降较缓慢且300 W处理10 min的水溶性下降得最慢.因此,在MPC生产过程中进行超声处理,可以在一定程度上减缓MPC贮藏过程中水溶性下降程度.     

Lipid Oxidation and Omega-3 Fatty Acid Retention in Salmon and Mackerel Nuggets During Frozen Storage

The extent of lipid oxidation and retention of omega (ω)-3 fatty acids in milk protein concentrate (MPC)-added mackerel and salmon mince and nuggets during 4-months frozen storage were investigated in order to develop high ω-3 seafood products. Mechanically deboned fish mince formulated with MPC and other ingredients was formed into batter-breaded nuggets with or without par-frying. The addition of MPC at 4% resulted in significantly lower thiobarbituric acid reactive substances (TBARS) values and helped retain significantly (p < 0.05) higher amounts of docosahexaenoic acid (DHA) in both salmon and mackerel mince and eicosapentaenoic acid (EPA) in the mackerel mince. There were no significant differences in peroxide values (PV) and TBARS values between nugget products with and without par-frying. EPA and DHA were retained less in par-fried than raw nuggets probably due to oil leaching and thermal degradation during frying. The reductions of EPA and DHA in salmon were 67% and 53% for raw and 57% and 39% for par-fried nuggets, while in mackerel they were 63% and 73% for raw and 57% and 56% for par-fried nuggets, respectively. Results suggest that although MPC provided some protection against lipid oxidation, additional measures are needed to improve retention of ω-3 fatty acids in mince-based seafood products during frozen storage.     

Control of Lipid Oxidation and Texture Changes in Frozen Sardine Mince by Combined Use of Milk Protein Concentrate and Caffeic Acid

The effectiveness of milk protein concentrate (MPC) and caffeic acid in controlling lipid oxidation and texture changes in 6-month frozen stored sardine mince was investigated using two different concentrations of caffeic acid (200 and 400 ppm) with and without MPC (4%). The extent of lipid oxidation was monitored by measuring thiobarbituric acid reactive substances (TBARS) while changes in the texture of mince due to frozen storage were assessed using Texture Analyzer (TA.XT Plus) and sensory analysis. Cooking loss upon frozen storage was also determined. The addition of MPC and/or caffeic acid significantly reduced lipid oxidation throughout the storage period. However, neither added benefit nor synergistic effect in retarding lipid oxidation was shown by caffeic acid. MPC not only retarded lipid oxidation but also moderated texture hardening, cooking loss, and moistness during frozen storage. No improvement by caffeic acid alone and no significant differences in sensory firmness and moistness between MPC-added mince with and without caffeic acid indicate that caffeic acid did not play any role in texture and moisture control. This study suggests that lipid oxidation and texture of frozen sardine mince can be better controlled by using MPC alone.     

基于切换控制的温室温湿度控制系统建模与预测控制

为解决温室环境系统的建模与控制问题,该文提出一种基于切换的温室建模方法与预测控制方法,该方法具有结构简单、模犁有效、控制稳定等优点;并以温室实际运行效果为例,说明了文中提出的建模和控制方法的有效性.     

粮食干燥机的自动控制

综述了粮食干燥机自动控制的发展现状，通过对粮食干燥机的反馈控制，前馈控制，反馈＋前馈控制，自适应控制，模糊控制及基于模型的MPC控制等自动控制方法的介绍，分别说明了各种控制方法的优缺点，并对干燥机自动控制系统的特点及要求进行了说明。     

恩诺沙星控制草鱼维氏气单胞菌的用药方案

从四川成都一养殖场大规模发病死亡的草鱼(Ctenopharyngodon idella)病灶处分离一株病原菌CiAV01,结合形态学和16S rDNA序列分析,鉴定该菌为维氏气单胞菌(Aeromonas veronii)。回归感染实验结果表明,分离菌株感染草鱼致死率为100%,出现了局部出血、腹腔积水等症状。采用琼脂平板扩散法研究了16种抗生素对分离菌株CiAV01的体外抑菌作用,在供试的抗生素中,恩诺沙星对该分离菌株CiAV01最为敏感。选择恩诺沙星对分离菌株进行体外药效学研究表明,恩诺沙星对分离菌株CiAV01的最小抑菌浓度(MIC)为0.25μg/mL,最小杀菌浓度(MBC)为0.50μg/mL,MBC/MIC为2。结合其药物动力学参数和MIC、MBC、防突变浓度(MPC)、突变选择窗(MSW)和抗菌后效应(PAE)制定防突变给药方案为:剂量20 mg/kg、每日一次给药、连续给药3～5 d。     

冷冻浓缩橙汁中柠檬酸钾结晶(MPC)的研究

文中介绍了冷冻浓缩橙汁中“不明”砂状该结晶物柠檬酸一钾（MPC），探讨形成MPC结晶的三大因素：热力学趋向性、pH值和结晶形成的速度。并给出相关的方法用于指导如何区分出已含大量MPC结晶的浓缩橙汁。     

联合用药缩小凡纳滨对虾斑点气单胞菌耐药突变选择窗的研究

通过测定斑点气单胞菌单药和双药抗生素最低抑菌浓度(MIC)、防突变浓度(MPC)和耐药突变选择窗(MSW),探索合理使用抗菌药物,防止细菌耐药性产生的用药方案。利用药物敏感性实验测定斑点气单胞菌对10种抗生素的抗性,筛选出6种不同机制的敏感性抗菌药物,应用琼脂平板稀释法对斑点气单胞菌测定单药以及双药的最低抑菌浓度(MIC)和防突变浓度(MPC),计算选择指数(SI)和联合指数(CI),测定联合用药对耐药突变选择窗(MSW)的影响。结果显示:6种药物氯霉素、土霉素、利福平、红霉素、盐酸四环素、头孢霉素的MIC分别为0.512、0.416、6.272、2.048、0.386和0.512μg/m L;MPC分别为524.288、1 277.952、802.816、1 024.000、1 185.792和10.880μg/m L;SI值分别为1 024.000、3 072.000、128.000、500.000、3 072.000和21.250。土霉素与红霉素、盐酸四环素与红霉素、盐酸四环素与头孢霉素、土霉素与头孢霉素、盐酸四环素与土霉素、氯霉素与土霉素、氯霉素与盐酸四环素、利福平与氯霉素、利福平与头孢霉素、利福平与盐酸四环素、利福平与土霉素、红霉素与头孢霉素双药联合后的联合指数分别为1.000、1.000、1.000、1.000、0.834、1.500、1.500、0.834、2.000、2.000、1.000和2.000。双药联合明显降低了药物SI值,有效缩小了斑点气单胞菌耐药突变选择窗,其中利福平与盐酸四环素双药联合后SI值由128.000,3 072.000均降低至1.000,完全关闭了耐药突变选择窗,有效抑制斑点气单胞菌的耐药生长。     

GPRS在农业旱情监测系统中的应用研究

为了实现农业旱情自动化监测,该农业旱情监测系统利用中国移动通信强大的GPRS网络,结合单片机、传感器和GPRS通信模块进行数据的传输,建立了完整的农情监测体系,实现了农业旱情实时、快速、可靠的传输.同时,分析了该系统的原理、组成以及实现方法,并通过仿真进行了系统的可靠性分析.