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1.
Oxidation of fats and oils during storage causes their degradation and loss of nutritional value and appearance. Electron spin resonance (ESR) is the only method that can be used to directly observe the radicals. In this study, the authors used an ESR spin-trapping method to study the oxidation of triacylglycerols (TAG) containing different fatty acids (FAs) commonly found in food. The ESR adduct signals were analyzed to study the effect of double bonds and the chain length of the FAs of TAG on oxidation. Oxidation was conducted by applying UV irradiation to TAG by dissolving it in N-tert-buthyl〈t-phenylnitrone (PBN), which trapped the radicals induced in the TAG as an ESR adduct signal. The detection was clearly successful. There were no differences in the spectra of tristearin (18:0) and tripalmitin (16:0); thus, it can be concluded that the length of the carbon chain of the FAs of TAG does not affect the oxidation reactions. However, the ESR spectra of tristearin (18:0), triolein (18:1) and trilinolein (18:3) were clearly different due to the presence/absence of a new peak corresponding to new induced radicals, leading to the conclusion that double bonds play a major role in the oxidation reactions of fats and oils.  相似文献   

2.
This article summarized the technology of sub-critical water extraction advancing in recent years,mainly including the extraction principle,experimental apparatus,influencing factors.Compared with the other methods,the SWE method is more rapidity,more convenient and no organic solvent,thus SWE was called as a green,environmental protective technique.Then it reviews the recent application of meat detection.  相似文献   

3.
Nitrate is closely related to the content of nitrosamine,which is known to be toxic and is determined in aquatic products.In this paper,a new sensitive UV spectrophotometry method based on K-model for rapid determination of nitrate in different kinds of samples was developed.The UV characteristic absorbance points of nitrate were selected and optimized.Under the optimized experimental conditions the calibration equation and K-model were obtained.The calibration curve is linear in the concentration range of 1 to 100μg/ml(R2=0.9973).This method was found to exhibit good accuracy,precision and repeatability.The developed method could be applied to the determination of nitrate in aquatic products and other food products.  相似文献   

4.
李姗姗  曹红梅  艾丽  徐明  朱亚伟 《丝绸》2022,(12):46-53
Synthetic fibers are widely used because of their stable chemical properties high mechanical strength and low cost. Among them polyester has the largest production and is the most widely used and China is also the country with the largest polyester production in the world. With the technological progress of energy saving and emission reduction of liquid disperse dyes the technology of micro printing of polyester and polyester / spandex fabrics has been realized. Based on the high market share of black polyester / spandex printed fabrics and the increasing market demand for functional finishing (e. g. anti-static finishing water repellent finishing UV resistance finishing etc.), it is of great significance to study the process of one-step short processing of polyester printing and functional finishing using carbon-based materials (e. g. carbon black). Carbon black is a gray-black organic pigment with good antistatic and anti-UV properties. It is an eco-friendly advanced material that integrates printing dyeing and functional finishing. To make up for the lack of color depth of carbon black pigment a disperse black dye and carbon black pigment in the same bath preparation scheme are chosen to prepare a functional liquid carbon black @ disperse black dye (CB-D). Not only does CB-D meet the requirements of deep black printing but also it can simultaneously provide water-repellent finishing to the fabric. In this way the application of organic fluorine or organic silicon resin can be dispensed with. A functional liquid CB-D was prepared by pre-dispersion and zirconium oxide grinding method under the action of abrasive agent AL50 (anionic / non-ionic surfactant complex) . The effects of CB-D mass fraction binder type binder D101 mass fraction baking temperature and time on color (L∗ value) rubbing and soaping colorfastness were investigated by optimizing the printing process of liquid CB-D. At the same time the fixation mechanism of CB-D was investigated and the properties of polyester-spandex printed fabrics were tested. The stability of CB-D and the colorfastness of polyester-spandex printed fabrics to hot-wash effluent were investigated by the rate of change of absorbance. The effect of hot-washing on dye floating in the printed area and dye staining in the non-printed area was characterized by the brightness of the printed area L∗ value and the whiteness of the non-printed area (CIE whiteness W10). The properties of CB-D were characterized by scanning electron microscopy and transmission electron microscopy and the antistatic property water repellency air permeability moisture permeability and tensile breaking strength of the fabrics were tested. (i) The first functional liquid CB-D with excellent stability is prepared by grinding carbon black and disperse black dye composed of orange 288 purple 93 and blue 291:3 in the same bath. (ii) A durable fluorine-free and silicone-free water repellent black polyester spandex fabric is prepared reducing the cost of functional finishing and environmental pollution. The preparation of durable water-repellent polyester spandex fabrics without a functional finishing agent is a new technology. CB-D as functional organic melanin with excellent performance and simple processing is a new low-carbon and eco-friendly material and ecological printing and dyeing process. (i) As for the black polyester spandex fabric prepared by a micro-printing process the color fastness of deep black color is not less than grade 4 the white ground is not stained and the color of wastewater is very low. The printing process requires 5% functional CB-D and 8. 5% binder D101. (ii) The black polyester spandex fabric has excellent and durable water repellency air permeability moisture permeability and antistatic property. The water contact angle is 132° anti-static grade is A and the air permeability and moisture permeability are more than 260 mm / s and 2 880 g / (m2h) respectively. After 30 times of home washing it almost keeps the original excellent performance. (iii) The CB-D prepared based on carbon black and disperse black dye is a colloidal aggregate that easily forms continuous carbon black aggregates on the fiber surface showing more excellent porosity film formation and water repellency while maintaining air permeability and moisture permeability. Carbon black is a low-cost material and the liquid CB-D prepared by modifying carbon black with disperse black dye has a new use in preparing functional textiles with good application prospects. © 2022 Authors. All rights reserved.  相似文献   

5.
ructure of finished fabric was hardly changed after finishing,however,the thermal stability of treated fabric was improved to a certain extent and the absorption peak of new group generated from some cross-linking r  相似文献   

6.
The term "Wool" is generally understood to refer to the fleece obtained from sheep, Sheep was probably one of the first animals to be domesticated and wool was one of the natural fibres that mankind earliestly and successfully made into a fabric, as far back as the remote stone age. In the beginning primitive sheep were covered with hair, and wool was merely a soft, slight down next to the skin, as is still true of some native unimproved sheep of present time. Because of the many environmental adaptions, it is impossible to determine the many original breeds of sheep contributing to modern types. Most fleece wools for textile use can be classified on the basis &f fineness and length into one of five types. (?)ine wool, medium wool, long wool, crossbred wool and carpet, or mixed wool. Only the Merino family can be classified as fine wool breeds. The ancestor of the finest wool —  相似文献   

7.
The purpose of this study was to determine the occurrence and antimicrobial resistance of Streptococcus spp. isolated from fresh ewe's milk and consequently to draw conclusions concerning the health condition of the animal flocks and the current trends of antibiotic use in small ruminants. A total of 77 mountainous sheepfolds were investigated representing 10% of all transhumant sheep and goats flocks in the area. Duplicate milk samples were collected from January to February transferred to the laboratory and analyzed for the presence of Streptococcus spp. by using the serial dilution method and plating on the surface of Slanetz and Bartley agar. The isolates were tested against nine antimicrobial agents with the Kirby-Bauer disk diffusion method. The results showed that Streptococcus spp. occurred in 84.4% of the samples and in counts ranged between 1.8 log CFU/mL and 4.6 log CFU/mL. Concerning susceptibility, only 1.3% of the isolates were resistant to all antimicrobials while 27.3% were fully susceptible. Resistance to cefepime was the most common (93.1%) observation followed by resistance to ampicillin (82.1%), ciprofloxacine (58.3%) and meropenem (51.9%). The isolates were vancomycin susceptible at a rate of 83.6%. Multidrug resistance to at least three antibiotics was observed to be 22.1% of Streptococcus spp.. Given the prevalence of Streptococcus spp. and the elevated resistance of isolates to various antibiotics it is concluded that further examinations and even interventions are required in order to pertain the appropriate animal health and milk quality.  相似文献   

8.
Antimicrobial treatments of textiles, especially cotton and synthetic fibres, have attracted considerable attention in research and manufacturing. The treatments prevent odour formation and fabric deterioration that arise from the growth of microbes on the textiles during their use or storage. However, wool is more difficult to treat due to its unique surface properties. In this report,we demonstrate that the pretreated wool was also able to exhaust up to 10% ( owf ) (on weight of fabric) of benzalkonium chloride,a cationic quaternary ammonium salt with biocidal activity. The exhaustion on the pretreated wool did not vary between 20 °C and 60 °C and was slightly affected by acidic pH value. Wool fabrics finished with 6% (owf) or more benzalkonium chloride exhibited strong antimicrobial abilities, deactivating 95. 5% ∼99. 9% of E. coli in quantitative antimicrobial assays.  相似文献   

9.
In our context, and in the goal to valorize the Pistacia atlantica species Desfthat grows spontaneously in Algeria occidental except the coastline, and that is used by the nomadic populations in their daily consumptions, we are thinking about drying its leaves. Here, the biochemical analysis of dried leaves ofPistacia atlantica is determined, the sorption is other ms are of great importance in the food industry, especially in the drying; the sorption isotherms of pistachio leaves were measured by the gravimetric method at three temperatures 40, 50 and 60 ℃. The equilibrium was achieved after eight days for desorption and seven days for adsorption with water activity ranging from 5% to 90%. Only the GAB and Peleg models were found to be the most suitable for describing the sorption curves. The isosteric heat of sorption of Pistacia atlantica leaves decreases with an increase in moisture content and was found to be an exponential function of moisture content for adsorption and desorption. The pistachio leaves could be considered as a rich natural source of valuable nutriments (carbohydrates, proteins and lipids); lipid fraction is equal to 2.25%; proteins are the second macronutriment that predominates in these sheets: 4.35%; accordingly carbohydrates content was about 25.77%.  相似文献   

10.
The silk fiber has an irreplaceable position in textile fibers and related silk fabrics have the advantages of light and airy texture good moisture absorption and breathability comfort in wear etc. It is also widely used in other fields such as the biomedical sector. However silk also has its own limitations poor light resistance and susceptibility to ultraviolet light especially the ultraviolet light of 290-400 nm wavelength in daylight such as under which condition it is prone to yellowing and photodegradation. The yellowing of silk is due to the photo-oxidation of tyrosine and tryptophan in silk protein under the action of ultraviolet light from sunlight and due to the production of yellow substances which affects the whiteness of silk. In addition from the molecular structure of silk most of the amino acids susceptible to UV light are distributed in the amorphous region. As the amorphous region is affected the structure of the crystalline region is also gradually relaxed the local degradation begins and the silk protein macromolecule chain is cleaved which leads to the decrease of the mechanical properties of silk fibers and accelerates the aging of silk fibers and fabrics. Therefore it is necessary to modify the silk products outside the anti-purple line. The current methods used to modify silk are mostly for post finishing modification including coating impregnation and chemical grafting methods but these methods often affect the original color or feel of the fabric and the durability of the modified effect is also poor. The feeding method is a green method to obtain modified silk by spraying mulberry leaves or artificial feed mixed with modifier which is ingested by silkworm and transferred to silk gland. In this study five aminobenzene UV absorbers were used as exogenous additive food for silkworms. The effect of molecular polarity on the transport of modifiers to silk glands was investigated and their effects on silkworm development and silk structural properties were studied. It was found that the aminobenzene UV absorbers were more easily transferred to the central silk gland silk glue and less to the posterior silk gland (fibroin). 4-dimethylaminobenzoic acid was found to be the highest in the posterior silk gland with a content of 3. 27 μg / strip. The cocoon width and cocoon quality of this group were significantly lower than those of the control group and the silk gum content was increased when this group was used as the study object. Compared with the control group the relative content of β-folded structure and crystallinity of the silk in the addition feeding group decreased slightly. The silkworm silk in the feeding group showed a certain UV absorption ability. After 330 h UV irradiation the breaking strength and elongation of the control group decreased by 48. 95% and 43. 52% respectively while those of the feeding group decreased by 42. 03% and 34. 18% respectively. In this paper UV absorbers were added to silkworms to obtain modified silk mainly focusing on the transfer of the modifier to the silk gland and the structural properties of the modified silk only for the most UV absorbers to enter the silk gland of the posterior group of silk. Other properties of the modified silk such as washing resistance have not been studied and some more in-depth studies are required. For instance it needs to be studied in depth for the limited absorption of exogenous additives by silkworms additive food's being not always absorbed by silkworms and transferred to the silk gland and the mechanism of action between the additive food and silk protein after the former's entering the silk gland. © 2022 Authors. All rights reserved.  相似文献   

11.
二次滤波法在织物疵点边缘检测上的应用   总被引:1,自引:0,他引:1  
针对织物图像斑点噪声的特点,采用了一种新的图像边缘检测方法。该方法以锐化处理为基础,经二次滤波完成图穰预处理,克服了以往一次滤波方法的缺点,在抑制噪声的同时,增强了图像的边缘信息。通过对织物疵点的检测表明,该方法可以取得较好的边缘检测结果,是一种实用有效的方法。  相似文献   

12.
Matrix singular value decomposition technique is employed for the detection of defects in fabrics. Firstly, a region of interest (ROI) containing the defect is identified by a proposed adaptive partitioning technique – thus reducing the computational duty of operating over the whole image. The ROI portion of fabric image is then divided into small nonoverlapping subimages to further reduce the computational complexity and the average singular values of the subimages are calculated. To remove the interlaced warp–weft grating structure from ROI, which is the global information in the fabric image, selected singular values associated with positive average singular numbers are rejected and the fabric image is reconstructed to yield the image of the defect. Since the resulting image is saturated with noise and some unconnected parts mainly due to dissimilarity of the subimage of the fabric structure, postprocessing is carried out by binarization and edge detection to yield the edge map of the defect. Validity and feasibility of the proposed approach is established for detection of defects form images of TILDA database. The detection rate of 95% and detection success rate of 94.1% are achieved when tested over 460 samples.  相似文献   

13.
机械图像处理技术在织物疵点检测中的应用   总被引:1,自引:0,他引:1  
提出了一种基于机械图像处理技术的织物疵点检测新方法.首先对采集的织物图像进行小波变换,对增强后的疵点图像采用最佳阈值分割和形态学运算,最后对织物疵点进行边缘检测.比较表明,新方法优于经典的边缘检测方法,对织物疵点边缘检测更为有效.  相似文献   

14.
织物疵点是影响织物价格的重要因素,一直以来都备受关注.随着科学技术的发展,对智能化需求的提高,织物疵点的自动检测成为纺织行业的热门话题.织物疵点自动检测系统在市场上已经有了较为成熟的产品,国内的主流方式仍为机下检测,对平整布面检测效果较好.根据图像处理的方法可将检测算法分为结构法、统计法、频谱分析法、基于模型的方法、基...  相似文献   

15.
Shengqi Guan 《纺织学会志》2013,104(12):1560-1573
Due to a large variety of fabric defects, the traditional detection method is difficult to meet the needs of dynamic detection that include all kind of defects. In order to enhance the effect of fabric defects detection, this paper proposed a dynamic delaminating detection method that fabric defects in the HSV color space are detected according to the fabric defect saliency. The idea is simulating the human visual system, and gradually enhancing the saliency of fabric defects through the data-driving. By the way, different types of defects are highlighted in different layers. At the same time, some task factors are used to drive form detection interest region in each layer. Then all kinds of defects are delaminated detection by setting a threshold in different layers. Experiments show that the proposed algorithm can accurately detect all kinds of defects, and have a strong universality for various types of defect detection. It can provide a possibility for the realization of fabric defects automatic detection.  相似文献   

16.
探讨织物疵点自动检测的方法。通过对4种常见织物疵点的图像进行线灰度曲线分析和处理,提取疵点图像的特征值,送入BP神经网络进行识别,从而实现织物疵点的检测。试验结果表明,该方法取得了较好的检测效果,织物疵点识别率达到93%以上。认为,此法能够有效识别出织物中的几类常见疵点,应进一步研究,以提高其识别准确率。  相似文献   

17.
张波  汤春明 《纺织学报》2017,38(5):145-149
为解决目前基于图像处理的织物瑕疵检测算法中,因织物纹理的多样性与瑕疵形状尺寸的不确定性所造成的检测效果差的问题,提出一种基于结构-纹理模型与自适应数学形态学的织物瑕疵检测算法。首先采用相对总变差模型对织物图像进行滤波以去除织物纹理,然后在得到的灰度图像上直接进行基于自适应邻域的灰度形态学运算,形态学算子采用开运算算子,最终得到织物瑕疵的增强图像。采用基于相对总变差模型与自适应形态学相结合的方法与2种已知的Gabor算法进行比对,对4类典型织物瑕疵进行检测实验和分析。结果表明,本文方法能更好地提取出织物瑕疵。  相似文献   

18.
将信息熵引入图像处理中,把疵点图像分为背景和目标两部分,分别对两个区域进行处理;通过求最大熵值的快速迭代算法,在满足信息熵最大要求的前提下对织物疵点区域进行分割,然后利用Canny边缘检测算子对分割后的疵点图像进行边缘检测,从而达到识别织物疵点的目的。仿真实验结果表明,将最大熵快速迭代算法与边缘算子结合进行疵点分割识别的方法是有效的。  相似文献   

19.
为了更准确识别织物疵点以及提高在线检测的实时性,研究了一种基于三维编码彩色光栅的织物疵点检测方法,并对其检测效果进行了试验。结果表明:通过在织物表面投射一幅固定彩色光栅的编码方法,就可以解算出织物的三维骨架信息,再将此信息转换成两坐标平面的数据信息,即可进行疵点的识别与分类,经测试,该法误检率为2.85%。指出:该检测方法具有较高的可行性和可靠性。  相似文献   

20.
李强  过玉清  纪峰 《纺织学报》2008,29(3):34-37
提出一种基于仰视投影的织物悬垂性测量方法。采用CCD摄像头采集织物悬垂边缘的仰视投影图像,并对其进行图像处理和边缘检测,得到完整的织物悬垂边缘数据;对因投影关系而产生畸变的数据进行矫正;计算得到表征织物悬垂性的参数指标。采用传统的基于俯视投影的织物悬垂性测试方法对织物进行测试,得出实验数据。结果表明,基于仰视投影的新型织物悬垂性测试方法可以避免传统俯视投影测量方法在测量轻、薄、柔软织物时,因皱褶折到支撑盘的边缘内部而造成的不可避免的误差。  相似文献   

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