基于可见光图像分析和支持向量机的鸭蛋新鲜度识别

研究鸭蛋内部的可见光图像信息(H和I)的变化来表征鸭蛋新鲜度的变化。采用可见光图像分析技术获取鸭蛋蛋心颜色参数, 将哈夫单位作为新鲜度的验证指标, 建立了基于支持向量机(SVM)的蛋心内部色泽参数的鸭蛋新鲜度预测模型。模型表明：当SVM类型为epsilon-SVR, 核函数为RBF模型特征参数C=27、σ=23时所建立的模型预测效果最好。其中模型预测效果参数RMSEC=0.9520, EMSEP=0.4205。鸭蛋新鲜度预测值与测定值之间具有良好的线性关系, 且预测值对实际值具有较大的搜索覆盖能力。该模型较好的解决了用普通的线性方法识别鸭蛋新鲜度存在的稳定性较差和置信度较小的问题。通过比较SVM和神经网络的识别结果可以发现：SVM对鸭蛋蛋心颜色的识别性能优于神经网络的识别性能(SVM: 98.92%>ANN: 93.77%)。     

洁净室服装静电和洁净性能测试方法的研究

洁净室、洁净室服装对于现代工业的作用日益重要。参考国内外标准,并根据实际工作经验总结,从洁净室服装的作用原理、测试指标和测试方法等角度,对洁净室服装的洁净性能和静电性能的测试进行了分析与研究。     

柠檬酸处理对采后芒果保鲜效果的影响

为探索芒果采后果实保鲜新方法,“台农一号”芒果采后分别经0(对照)、5、10mmol/L 柠檬酸浸果10min后,常温贮藏,定期检测果实的常规品质、成熟进程和病情发展的变化。结果表明：柠檬酸处理使果实软化、果肉可溶性固形物增加及可滴定酸含量降低的速率减缓,果实的转黄指数和病情指数降低,说明适当水平的柠檬酸处理能有效延缓芒果采后果实的成熟进程,并且抑制果实腐烂发生。柠檬酸处理是芒果采后贮藏保鲜的一种可选新方法。     

Effect of mixing process on the luminescent properties of SrAl_2O_4:Eu~(2+),Dy~(3+) long afterglow phosphors

A new mixing method was developed for solid-state reaction synthesis of SrAl2O4:Eu2+,Dy3+ long afterglow phosphors.The morphology and crystal structure of the phosphors were analyzed with scanning electron microscope(SEM) and X-ray diffractometer(XRD).The excitation and emission spectra of the long afterglow phosphors were measured,and the main emission band was around 514 nm.The decay time of the product was measured and compared with the phosphors prepared using dry-mixing method and wet-mixing method.It ...     

坝工混凝土耐久寿命的衰变规律

 论述了坝工混凝土及其建筑物的寿命，以及耐久寿命衰变规律，对混凝土坝必须引入设计寿命的追求目标，国外坝工界认为混凝土坝的耐久寿命至少100 a。在混凝土材料中存在一种最理想的长寿混凝土，即W0／C =0.38　波特兰水泥引气混凝土，其成熟的混凝土的“半衰期”可达约350 a，“平均寿命”可达500a。     

用于核态寿命测量的X—γ—γ定时符合系统

由两只ＢａＦ２闪烁探测器和一只高纯锗探测器组成的延迟符合系统适用于电子俘获衰变和Ｅ０跃迁生成的ｎｓ和ｐｓ量级激发态寿命测量。快符合涉及特征Ｘ射线和相应的级联衰变γ射线测量，系统具有元素和级联选择的优点。该系统对放射性核素１５２￣Ｅｕ进行测量，除得到Ｘ－γ－γ瞬发时间谱的半高全宽度外，还分别得到１２１．７８ｋｅＶ和３６６．４８ｋｅＶ能级的半寿命分别为１．３９５±０．０３５ｎｓ和４８±１０ｐｓ。结果表明该系统适用于Ｚ≥６２的电子俘获衰变研究。     

Mathematical modeling of polish-rate decay in chemical-mechanical polishing

A model is presented for polish-rate decay in chemical-mechanical polishing based on the Greenwood-Williamson theory of contact between a smooth surface (a wafer) and a rough surface (the polishing pad). The model assumes that polishing causes pad asperities to wear, with high asperities wearing faster than low asperities. Model predictions of the time dependence of polish-rate decay compare favorably with experiments.     

碳纤维表面等离子处理及其效果的研究

通过扫描电镜（ＳＥＭ）、Ｘ射线表面能谱（ＸＰＳ）、激光喇曼光谱（ＬＲＳ）以及动态毛吸浸润（ＤＣＷ）等分析方法研究了等离子处理前后碳纤维表面化学结构及浸润特性的变化，并发展了一种以１，１－二苯基，２－苦基肼（ｄＰＰｈ）为探针，利用紫外可见光谱分析碳纤维表面酚羟基、酿基以及等离子处理后产生的游离基的新方法ＤＰＰＨ。通过该方法的分析，确定了等离于处理碳纤维的最佳工艺条件。     

Packaging for freshness and the prevention of discoloration of fish fillets

Fillets of various kinds of fish are currently packed in thin films (e.g. polyvinyl chloride) for sale at supermarkets; however, these fillets are not necessarily fresh or of good quality. Packed fillets must be certified for safety, freshness and quality, because sensory judgement is difficult. In order to understand how the freshness and colour of red fish meat can be retained, the methods of packaging were examined. It was known that for freshness the packed fillets must be kept at a low temperature, but discoloration of red meat could not be prevented by this alone. However, discoloration of red-meat fish, such as yellowtail and oceanic bonito, can be prevented by packing with nitrogen gas (N₂).