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71.
72.
Wash water is circulated for use in the minimal processing industry, and inefficient disinfection methods can lead to pathogen cross-contamination. Moreover, few disinfection strategies are available for ready-to-eat fruits that do not need to be cut. In this study, the use of chlorine and ultrasound, two low-cost disinfection methods, were evaluated to disinfect winter jujube, a delicious, nutritious, and widely sold fruit in China. Ultrasound treatment (28 kHz) alone could not decrease the cross-contamination incidence of Escherichia coli O157:H7, non-O157 E. coli, and Salmonella Typhimurium, and free chlorine treatment at 10 ppm decreased the incidence from 55.00% to 5.00% for E. coli O157:H7, 65.00% to 6.67% for non-157 E. coli, and 70.00% to 6.67% for S. Typhimurium. The cross-contamination incidence was completely reduced (pathogens were not detected in sample) when the treatments were combined. The counts of aerobic mesophiles, aerobic psychrophiles, molds, yeasts, and three pathogens in the group subjected to combination treatment (28 kHz ultrasound + 10 ppm free chlorine) were significantly lower than those in the control, chlorine-treated, and ultrasound-treated groups during storage (0–7 d at 4 °C). Analysis of weight loss, sensory quality (crispness, color, and flavor), instrument color (a*/b*), soluble matter contents (total soluble solids, reducing sugar, total soluble sugar, and titratable acid), and nutritional properties (ascorbic acid and polyphenolic contents) indicated that treatment with ultrasound, chlorine, and their combination did not lead to additional quality loss compared with properties of the control. Additionally, the activities of phenylalanine ammonia-lyase and polyphenol oxidase were not significantly increased in the treatment group, consistent with the quality analysis results. These findings provide insights into disinfection of uncut ready-to-eat fruits using a minimum dose of disinfectant for cross-contamination prevention under ultrasonication. The use of ultrasound alone to decontaminate fresh produce is accompanied by a high risk of pathogen contamination, and the use of sanitizers to decrease cross-contamination incidence is recommended. 相似文献
73.
We propose a new quantum watermarking scheme based on threshold selection using informational entropy of quantum image. The core idea of this scheme is to embed information into object and background of cover image in different ways. First, a threshold method adopting the quantum informational entropy is employed to determine a threshold value. The threshold value can then be further used for segmenting the cover image to a binary image, which is an authentication key for embedding and extraction information. By a careful analysis of the quantum circuits of the scheme, that is, translating into the basic gate sequences which show the low complexity of the scheme. One of the simulation-based experimental results is entropy difference which measures the similarity of two images by calculating the difference in quantum image informational entropy between watermarked image and cover image. Furthermore, the analyses of peak signal-to-noise ratio, histogram and capacity of the scheme are also provided. 相似文献
74.
研究时标T上的一类具非正中立项的非线性非自治二阶动力方程的动力学性质.利用时标上的有关理论,并结合一些经典不等式,得到了该方程的一些新的动力学性质,进一步推广和完善了动力方程的动力学性质. 相似文献
75.
Let G =(V, E) be a simple connected graph with n(n ≥ 3) vertices and m edges,with vertex degree sequence {d1, d2,..., dn}. The augmented Zagreb index is defined as AZI =AZI(G)=∑ij∈E(didj/di+dj-2)3. Using the properties of inequality, we investigate the bounds of AZI for connected graphs, in particular unicyclic graphs in this paper, some useful conclusions are obtained. 相似文献
76.
We report on a theoretical study of spin-dependent Goos-Hänchen (GH) shift of electrons in antiparallel double δ-magnetic-barrier (MB) nanostructure under an applied voltage, which can be experimentally realized by depositing two metallic ferromagnetic (FM) stripes on top and bottom of the semiconductor heterostructure. GH shifts for spin electron beams across this device, is exactly calculated, with the help of the stationary phase method. It is shown that a considerable spin polarization of GH shifts can be achieved in this device for two δ-MBs with unidentical magnetic strengths. It also is shown that both magnitude and sign of spin polarization of GH shifts can be controlled by adjusting the electric potential induced by the applied voltage. These interesting properties may provide an effective approach of spin injection for spintronics application, and this device can be used as a voltage-tunable spin beam splitter. 相似文献
77.
在pH 7.6的磷酸氢二钠-磷酸二氢钠缓冲溶液中,羊抗人前白蛋白与前白蛋白发生特异性结合生成免疫复合物,导致体系的共振散射增强。体系在最大散射波长470 nm处,前白蛋白的质量浓度在0.067~2.82 mg.L-1范围内与共振散射增强强度(ΔI)呈线性关系,检出限(3S/N)为0.028 mg.L-1。应用于测定人血清前白蛋白,测定值相对标准偏差(n=6)在1.15%~3.00%之间。 相似文献
78.
79.
《Physics letters. A》1997,234(1):64-68
We present a study of thermal conductivity in the superconducting phase of the heavy fermion superconductor UPt3. The angular dependence of the thermal conductivity shows a cosine-square law when the magnetic field rotates in the basal plane. For a field rotating out of the basal plane, however, our results present features which can not be explained through our current conventional picture for vortex scattering of heat-carrying quasi-particles. 相似文献
80.