Hyperspectral Imaging-Based Classification and Wavebands Selection for Internal Defect Detection of Pickling Cucumbers

Hyperspectral imaging is useful for detecting internal defects of pickling cucumbers. The technique, however, is not yet suitable for high-speed online implementation due to the challenges in analyzing large-scale hyperspectral images. This research aimed to select the optimal wavebands from the hyperspectral image data, so that they can be deployed in either a hyperspectral or multispectral imaging-based inspection system for the automatic detection of internal defects of pickling cucumbers. Hyperspectral reflectance (400–700 nm) and transmittance (700–1,000 nm) images were acquired, using an in-house developed hyperspectral imaging system running at two conveyor speeds of 85 and 165 mm/s, for 300 “Journey” pickling cucumbers before and after internal damage was induced by mechanical load. Minimum redundancy–maximum relevance (MRMR) was used for optimal wavebands selection, and the loadings of principal component analysis (PCA) were also applied for qualitatively identifying the important wavebands that are related to the specific features. Discriminant analysis with Mahalanobis distance classifier was performed for the two-class (i.e., normal and defective) and three-class (i.e., normal, slightly defective, and severely defective) classifications using the mean spectra and textural features (energy and variance) from the regions of interest in the spectral images at selected waveband ratios. The classification results based on MRMR wavebands selection were generally better than those from PCA-based classifications. The two-band ratio of 887/837 nm from MRMR gave the best overall classification results, with the accuracy of 95.1 and 94.2 % at the conveyor speeds of 85 and 165 mm/s, respectively, for the two-class classification. The highest classification accuracies for the three-class classification based on the optimal two-band ratio of 887/837 nm were 82.8 and 81.3 % at the conveyor speeds of 85 and 165 mm/s, respectively. The mean spectra-based classification achieved better results than the textural feature-based classification, except in the three-class classification for the higher conveyor speed. The overall classification accuracies for all selected waveband ratios at the low conveyor speed were slightly higher than those at the higher conveyor speed, since the low speed resulted in more scan lines, thus higher spatial resolution hyperspectral images. The identified two-band ratio of 887/837 nm in transmittance mode could be applied for fast real-time internal defect detection of pickling cucumbers.     

Effects of medium composition on production of 5-aminolevulinic acid by recombinant Escherichia coli

The recombinant Escherichia coli BL21(DE3) harboring hemA from Agrobacterium radiobacter, which was engineered in our previous work, was used for the extracellular production of 5-aminolevulinic acid (ALA). The effects of various physiological factors, such as the concentrations of precursors (glycine, succinic acid and glucose) and the inhibitor 5-aminolevulinate dehydratase (levulinic acid), on the ALA accumulation in the fermentation broth were investigated in both shake flasks and a jar fermentor. Among these precursors, glycine exhibited the strongest ability to inhibit cell growth, while glucose mainly inhibited ALA formation. The optimum initial concentrations of glycine, succinic acid and glucose were found to be 2.0, 10.0 and 2.0 g/l, respectively. Levulinic acid (LA; 30 mM) was fed to the fermentation broth at the end of the exponential cell growth phase (about 8 h), and the intracellular activity of ALA dehydratase was efficaciously suppressed. Repeating the optimum composition of the medium in a stirred tank fermenter resulted in 1.49 g/l ALA. Furthermore, the fed batch of the precursors and inhibitor further increased ALA production up to 3.01 g/l.     

纤维素酶和米根霉同时糖化发酵纤维素为L-乳酸

研究了纤维素原料经机械粉碎、稀酸处理、氨处理、蒸爆水洗处理后 ,用里氏木霉所产纤维素酶和米根霉对其进行同时糖化发酵生产L 乳酸 ;并与稀酸处理物料分别酶解发酵进行了对比。结果表明 ,实验条件下 ,粉碎处理、稀酸处理、氨处理、蒸爆水洗处理物料的L 乳酸发酵产量分别为 13 4mg/mL、18 1mg/mL、15 5mg/mL和 19 6mg/mL ,与分别酶解发酵相比 ,同时糖化发酵过程周期短。     

香烟滤咀用细旦二醋纤纺丝技术研究

本文用面△０．０６—０．０６—２５０孔喷丝板单甬道干纺工艺连续纺制２．７５ｄｔｅｘ烟滤咀用细旦二醋纤，其强、伸度分别为１．２０ｃＮ／ｄｔｅｘ、０．２２．异形度为０．７７８结果达到烟用二醋纤的技术要求．     

黑龙江省大豆品种对大豆疫霉根腐病抗性评价及抗性基因推导

采用下胚轴伤口接种法,利用课题组在黑龙江省分离鉴定的8个大豆疫霉根腐病生理小种（race1、race3、race4、race5、race9、race13、race44、race54）对黑龙江省曾经大面积推广种植的44个大豆品种进行接种鉴定。结果表明,对8个生理小种分别有45.5%、29.5%、40.9%、43.2%、36.8%、45.5%、31.8%、72.7%表现抗性或中间类型,共产生37种反应型;通过基因推导,合丰-44,绥农-12可能含有Rps1c基因或Rps1a＋Rps1c、Rps1c＋Rps6、Rps1c＋Rps7的基因组合;黑河-32可能含有Rps1a＋Rps1d的基因组合,其它品种可能含有新的抗病基因或基因组合,表明黑龙江省存在丰富的抗大豆疫霉根腐病的种质资源。     

基于SmartPro的碱回收控制系统介绍

介绍北京和利时公司开发的SmartPro MACSⅢ在碱回收过程中的应用,包括硬件组成、软件设计及安全保护设计.实现了整个碱回收过程的自动化,提高了碱回收率.     

Two-step purification strategy for enhanced recovery of recombinant hepatitis B surface antigen from Pichia pastoris

Univariate screening on factors affecting the purification performance of recombinant hepatitis B surface antigen (HBsAg) on ion exchange chromatography (IEC) and size exclusion chromatography (SEC) and the establishment of a two-step purification strategy were performed. Amongst four IEC adsorbents examined, the use of Q Sepharose XL IEC adsorbent under optimized conditions together with optimized SEC purification was able to efficiently purify HBsAg. An established purification strategy comprising the two techniques further demonstrated adaptability for scale-up operations with a final total purification factor (PF) of 94.82 ± 16.20, HBsAg purity of 95.48% and recovery yield of 78.07%.     

Induction-heating ignition of pulverized coal stream

Induction-heating ignition burner for the pulverized coal fired boiler is introduced. Some experiments were conducted on an experimental set-up, which includes alternative current power system, induction-heating system, pulverized coal and air supplier system, and measurement system to study the ignition process of coal powder and air mixture stream. Some results are presented. An industrial induction-heating burner for a 220 t/h boiler, which was designed on the basis of a series of researches, is described. This kind of oil-free ignition burner is characterized by its stable operation performances, and the lower cost in its maintenance.     

Decomposition of hydriodic acid by electrolysis in the thermochemical water sulfur–iodine splitting cycle

Although several technologies, such as reactive distillation and catalytic membrane reactor, have been proposed to improve HI conversion efficiency, they still experience several challenges for the application in HI section. In this study, an electrochemical cell was employed for hydriodic acid decomposition under the presence of iodine. Several commercial proton-exchange membranes (PEMs), namely, Nafion 117 and Nafion 115, were used as separators for the electrochemical cell. Anodization of iodide anion occurred at the graphite electrode in the anode compartment. Hydrogen was generated by the reduction reaction of hydrogen cations, which migrated from anolyte to catholyte. In electrolysis experiments, PEM showed good performance in terms of high transport number of proton and low iodine permeation. Several parameters, such as operating temperature, HI molarity, and I₂ molarity in anolyte, which affected current efficiency, iodine permeance, and electric resistance of test cell, were investigated. High operating temperature and I₂ molarity in anolyte enhanced the permeability of iodine, which had several negative influences on electrochemical cell performance. Although current efficiency was negatively affected by increasing temperature and I₂ molarity, it still remained above 0.85 in the range of 30 °C–75 °C. Ohmic resistance, which is a component of cell resistance, offered by PEM was investigated with Nafion 117 and 115. Apart from graphite plates, activated carbon papers were adopted as electrodes to reduce the overpotentials due to their high specific surface characteristic.