基于近红外光谱和随机森林方法鉴别蜂蜜真伪

目的建立蜂蜜样品真伪鉴别的近红外光谱快速检测方法,为今后蜂蜜检验工作提供可靠参考依据。方法采用积分球透反射模式采集样品近红外光谱数据,以Savitzky-Golay 1阶微分方法对原始光谱进行预处理,以随机森林方法建立光谱数据与蜂蜜真伪的定性判别模型。结果所建立的判别模型中训练样本判别正确率为100%,测试样本判别正确率为95%。结论近红外透反射光谱技术应用于蜂蜜真伪鉴别的可行性,同其他分析方法相比具有操作简单、速度快、效率高、无污染、费用低、无需复杂前处理等优点。     

The Application of Near Infrared Spectroscopy to Evaluate Malting Quality

Near infrared (NIR) spectroscopy is a rapid technique which is used within plant breeding programs for the analysis of many grain traits. This study investigated the application of NIR analysis of wort samples to select malting quality cultivars in a barley breeding program. An automatic sampling and data capture system was developed which consisted of a Perten filter NIR instrument with a flow through cell module operating in transflectance mode interfaced with a computer, peristaltic pump and sample changer. Calibrations for hot water extract, free alpha-amino nitrogen and soluble protein were developed using multiple linear regression analysis based on four wavelength terms for each trait. The correlation coefficients for both calibration and prediction data sets were highly significant (P<0.01) and the standard error of prediction was similar to that obtained by standard methods. Cultivars with known malting quality were included in the experiments and their ranking by NIR was consistent with the standard methods. The reported calibrations have been used for over four years to screen early generation breeding lines for malting quality.     

提高禁用偶氮染料检测准确度缩短与国际标准的差异

将我国纺织品上禁用偶氮染料检测方法国家标准,与目前被全球采用的欧盟方法标准在技术条件和操作程序上进行了比较分析,找出了我国现行方法中在适用范围、样品预处理、定性/定量方法的选择等方面同欧盟方法存在的差异,指出了GB方法中影响检测准确度的因素,探讨了提高AZO检测准确度的措施。     

Identification of cattle, llama and horse meat by near infrared reflectance or transflectance spectroscopy

Visible and near infrared reflectance spectroscopy (VIS-NIRS) was used to discriminate meat and meat juices from three livestock species. In a first trial, samples of Longissimus lumborum muscle, corresponding to beef (31) llamas (21) and horses (27), were homogenised and their spectra collected in reflectance (NIRSystems 6500 scanning monochromator, in the range of 400-2500 nm). In the second trial, samples of meat juice (same muscle) from the same species (20 beef, 19 llama and 19 horse) were scanned in folded transmission (transflectance). Discriminating models (PLS regression) were developed against “dummy” variables, testing different mathematical treatments of the spectra. Best models indentified the species of almost all samples by their meat (reflectance) or meat juice (transflectance) spectra. A few (three of beef and one of llama, for meat samples; one of beef and one of horse, for juice samples) were classified as uncertain. It is concluded that NIRS is an effective tool to recognise meat and meat juice from beef, llama and horses.     

THE SEPARATION OF BARLEY PROTEINS BY DISC ELECTROPHORESIS USING POLYACRYLAMIDE

Protein components extracted from the barley varieties, Prior and Beecher, have been electrophoretically separated in acrylamide gels. The resolution obtained was sufficiently definitive to allow scanning by transmission densitometry. With the same solvent, similar electrophoretic patterns were obtained over a number of sequential extractions. However, with different solvents the patterns showed that individual proteins had been extracted in different proportions. The work presented emphasizes the need for clarification of the relative importance of the separated proteins.     

熔体计量泵变频控制方式的改造

熔体计量泵是我厂“熔体调整”新技术的关键设备之一,选用了西门子6SE3575新型变频机来控制和驱动。但是,由于调试期间对变频机控制方式选择不当,致使实际生产过程中出现很多问题,后经研究,将变频机原来的控制方式——“频率控制”改为“转速控制”,问题得到了解决,产生了良好的效益。     

THE EFFECT OF THE COLLOIDAL STATE OF THE EMULSION ON ICE CREAM STRUCTURE

Ice creams with different ‘stand-up’ characteristics have been prepared using the same basic mix but without emulsifiers. This has been achieved by allowing the gelatin stabiliser to compete for the oil-water interfaces in the emulsion yielding mixes of varying emulsion stability. The emulsion stability varies according to the ratio of gelatin to milk protein present at the homogenisation stage and shows a minimum which corresponds to ice creams with maximum stand-up. The data provides an independent check of the theory of Kloser and Kenney in mixes not containing lipid emulsifiers.     

THE AROMA OF CANNED BEEF: APPLICATION OF REGRESSION MODELS RELATING SENSORY AND CHEMICAL DATA

The purpose of this investigation was to determine general relations between instrumental and sensory aroma data from a reference material consisting of a large set of different types of beef samples analyzed during several years. The relations obtained in this way have been tested on independent "unknown" samples. Different models have been used, basically derived from Stevens' law and formulated in analogy with models used in other psychophysical contexts. From the reference material a great number of highly significant relations-several with a correlation coefficient greater than 0.90–were obtained for the various odor notes used. Several of these seem to be examples of causative relations. When predicting sensory properties of unknown samples almost all the relations obtained with high correlation coefficient worked very well. These properties could be predicted by the gas chromatographic technique with the same accuracy as when the panel assessed the samples. Therefore, by applying the models in a proper way, the panel service in routine analyses may be supplemented or refined by using a gas chromatographic technique. These methods may, of course, also be used in product and process development work.     

Study on heat transmission through multilayer clothing assemblies under different convective modes

The present work reports a detailed study on dry thermal resistance of multilayered clothing assemblies under different modes of heat transmission (i.e. non-convective mode, natural convection and forced convection). A series of multilayered fabric assemblies have been created with different combinations of fabric layers (like plain woven, nonwoven wadding, warp-knitted spacer fabric, weft-knitted breathable coated and weft-knitted aluminium coated) and air gaps of different thicknesses between fabric layers. Significant impacts of thickness of air gaps and mode of heat transmission on thermal resistance of multilayered clothing assemblies have been observed. The thermal resistance of the fabric assemblies increases with the increase in the thickness of air gap in between fabric layers. The thermal resistance of all the fabric assemblies at any given air layer thickness is highest under non-convective mode of heat transmission, followed by natural convection mode and the forced convection mode shows least thermal resistance. Incorporation of coated fabric in the outer layer reduces the effect of forced convection. ANOVA has been prepared and F value has been calculated to find the effect of modes of convection, type of fabric and thickness of air layer on thermal transmission properties. The results obtained from this detailed study will help in designing multilayered clothing assemblies suitable for different climatic conditions.     

Multivariate determination of free fatty acids and moisture in fish oils by partial least-squares regression and near-infrared spectroscopy

The oxidative and hydrolytic degradation of lipids in fish oil was monitored using partial least-squares (PLS) regression and near-infrared reflectance (NIR) spectroscopy. One hundred and sixty (n=160) fish oil samples from a fishmeal factory were scanned in transflectance by an NIR monochromator instrument (1100–2500 nm). Calibration models were performed for free fatty acids (FFA), moisture (M), peroxide value (PV) and anisidine value (AV). Coefficients of determination in calibration (R²) and standard errors of cross validation (SECV) were 0.96 (SECV: 0.59) and 0.94 (SECV: 0.03) for FFA and M in g/kg, respectively. The accuracy of the NIR calibration models were tested using a validation set, yielding coefficients of correlation (r) and standard errors of prediction (SEP) of 0.98 (SEP: 0.50) and 0.80 (SEP: 0.05) for FFA and M in g/kg, respectively. Poor accuracy (R²<0.80) was obtained for the NIR calibration models developed for PV and AV. The paper demonstrates that fish oil hydrolytic degradation of lipids, which seriously affect oil use and storage under industrial conditions, can be successfully monitored using PLS regression and NIR spectroscopy by the fishmeal industry.     

FK6-1000型加弹机第一罗拉张紧轮座板改造浅析

针对德国FK6 - 1000型加弹机的第一罗拉过桥传动给设备维护带来的一些不便,以及在使用过程中易造成设备损坏的现象,对其张紧轮座板进行了一些结构性的调整改造.改造后,大大降低了设备故障率,且对提高维修效率,保证维修质量起着较大的作用.     

5—THE FINITE-DEFORMATION THEORY OF PLAIN-WEAVE FABRICS. PART III: THE SHEAR-DEFORMATION THEORY

The over-all shear deformation, that is, the combined deformation of biaxial tensile and shear deformation is considered generally, and a theory by which the mechanical behaviour of fabrics in this slate can be determined is presented.

Experiments are also described that were made to confirm the accuracy of these theories by using a new biaxial tensile tester for the measurement of the tensile and shearing properties of the fabrics and by using newly designed testing instruments for the measurement of yarn properties.

Good agreement between the theoretical and observed data is shown, and the theories appear to have considerable potentialities in the practical design of fabrics.     

DETECTION OF THE SULPHURING OF HOPS DURING KILNING AND CULTIVATION

Since brewing companies are now reluctant to accept hops treated with sulphur during kilning and cultivation, methods have been developed for detecting such contamination. In the procedure for estimating residual elemental sulphur, milled hops are continuously extracted with cyclohexane and dissolved sulphur is deposited on copper gauze as copper (I) sulphide. Hydrogen sulphide is then formed by the addition of hydrochloric acid and is absorbed in potassium hydroxide solution. The dissolved sulphide is finally estimated by titration using p-chloromercuribenzoic acid and diphenylthiocarbazone as indicator. The modified Monier Williams procedure, as recommended by the Institute of Brewing for estimating sulphur dioxide in beer, has been adapted for analysing hops. This provides a convenient technique for determining whether or not hops have been treated with sulphur or sulphur dioxide during kilning. The sulphur dioxide content of fresh hops treated at normal rates is of the order of 800 mg/kg. A number of samples of hops from the 1980 crop have been analysed and the levels of sulphur dioxide were found to be within the range 1 to 80 mg/kg. It is likely that these low levels are the result of using fuel oils, which contain variable amounts of sulphur, to dry the hops.     

THE APPLICATION OF PORTION CONTROL OPTIMIZATION IN AN AUTOMATED CAN-FILLING PROCESS

The main objective of portion control is to ensure that desired portions, usually specified by weight, are placed in the packages. In can‐filling in particular, an optimal goal would be to minimize underfilling and overfilling. This paper develops an advanced packaging process for automated can‐filling of fish, which achieves this goal. The overall automated system uses an innovative technique of optimal overlapping and cutting of fish. First, a batch of fish are overlapped in a linear orientation where the ordering sequence, the head orientation, and the degree of overlap between fish are the variables of optimization. The optimization is carried out with the objective of minimizing the absolute total weight of underfill and overfill of the produced cans. The optimal portioning method should possess a computational speed that is consistent with the process speed and the filling accuracy requirements. Several models of optimization have been developed. This paper follows a model development procedure that realizes a feasible and practical model. A numerical example that uses real data on a batch of salmon is presented to illustrate the approach and to demonstrate its feasibility in achieving both optimization objective and the processing speed. A comparison of several optimization models that have been developed is given, with respect to the computational speed and the filling accuracy. Results show that the optimal portioning method is able to achieve high production rates and improved filling accuracy in can‐filling process of salmon.     

基于转矩控制模式的经编电子横移系统设计

针对目前采用的位置控制模式和速度控制模式无法满足高速经编机梳栉横移高定位精度、高动态响应需求的不足,设计了一种基于转矩控制模式的经编机电子横移系统,并设计出电子凸轮的运动规律曲线和运动控制卡的PID控制算法,实现梳栉横移的柔性冲击和高定位精度。通过理论与实践分析,推导出电机的选型计算公式,选择高响应伺服电机。并从梳栉横移振动和电机实际反馈速度分析验证了转矩控制模式下梳栉横移的高定位精度和高动态响应性。     

THE DETERMINATION OF GLYCOGEN IN YEASTS

Four methods for the determination of glycogen in yeast have been compared in five strains of Saccharomyces cerevisiae over a range of glycogen contents. A new method has been developed which is specific, precise and more exhaustive than previously published procedures. After extraction with sodium carbonate and perchloric acid, the glycogen was hydrolysed with amyloglucosidase to glucose, which was estimated enzymically. The greater extraction of glycogen using this method cannot be explained by acid hydrolysis of glucans prior to treatment with amyloglucosidase. Further, the older data using the non-specific methods can now be equated with values obtained using a specific method.     

Prediction of immunoglobulin G content in bovine colostrum by near-infrared spectroscopy

The objective of this work was to assess the potential of near infrared spectroscopy to predict the immunoglobulin G (IgG) content in bovine colostrum. Liquid colostrum samples (n=157) were collected from Holstein cows from 2 dairy farms in southern Chile. Samples were obtained within 1h of parturition and scanned in folded transmission (transflectance) in the visible-near infrared range. Multivariate regression models (modified partial least squares) were developed with spectral data against IgG content measured by radial immunodiffusion. The best calibration included a mathematical treatment of the spectra by a second derivative plus standard normal variate and detrending. The best equation explained a high proportion of the variation in IgG content (R(2) of 0.95 in calibration and 0.94 in cross-validation). Average (91.5 g/L), standard deviation (37.6g/L), and range, as highest minus lowest values (171.9 g/L) of reference values were 10.1, 4.2, and 19 times the value of the root mean square error of cross-validation (9.03 g/L) respectively. Near-infrared spectroscopy, scanned in folded transmission, is an effective tool to predict the IgG content in liquid colostrum.     

SVM法定性鉴别奶牛饲料中脲醛树脂的可行性研究

收集中国常用的、具有代表性的奶牛精补料44个样品,制备176个脲醛树脂(urea-formaldehyde resins,UF)掺假样品。在全光谱范围内进行近红外透反射光谱扫描,选择不同的归一化方式进行前处理,采用支持向量机(supportvector machine,SVM)方法,筛选最佳的预处理方法来建立定性鉴别模型。当采用归一化方式与主成分分析(principal component analysis,PCA)相结合时,所建立的SVM定性分析模型的预测精确率达到97.701 1%。说明利用近红外透反射光谱建立定性分析模型来检测奶牛饲料中是否掺有UF的研究是可行的。     

烤烟4O级制烟叶主要化学成分分析研究

通过对烤烟40级制各等级烟叶主要化学成分的测定,取得了一套系统完整的分析数据;分析研究了烟叶部位、颜色、等级、成熟度等因素与烟叶化学成分的关系,找出了规律性,为合理利用烟叶资源,指导卷烟配方,提高卷烟质量及开发卷烟新产品提供了科学依据。     

基于近红外光谱技术的沙棘籽油鉴伪方法研究

针对市场上沙棘籽油质量参差不齐的情况,结合近红外光谱技术研究沙棘籽油快速鉴伪的方法。采用234份沙棘籽油、其他植物油、掺假沙棘籽油的近红外透反射光谱,结合簇类独立软模式法(SIMCA)、偏最小二乘判别法(PLS-DA)、支持向量机法(SVM)3种化学计量学方法,在4 000~6 000 cm-1波段范围内分别建立这3类油的判别模型,并用117份独立样品对模型进行验证。结果表明:3种建模方法均得到了满意的结果,其中SVM在训练和验证过程中均得到100%的正确率,判别效果最好;近红外光谱技术应用于识别纯沙棘籽油和区分沙棘籽油掺假类别具有实用性,近红外光谱技术应用于沙棘籽油鉴伪是可行的。