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1.
Sun Yehan Su Qingtang Wang Huanying Wang Gang 《Multimedia Tools and Applications》2022,81(5):6091-6113
Multimedia Tools and Applications - With the rapid development of the Internet, the color digital image copyright protection is facing severe challenges. Simultaneously, the color digital images... 相似文献
2.
以从自然腐败的樱桃上分离的链格孢霉(Alternaria sp.)LD3.0086为指示菌,研究苯乳酸对链格孢霉的主要抑制作用靶位。应用分光光度法测定苯乳酸对链格孢霉的最小抑菌浓度,通过卡尔科弗卢尔荧光增白剂染液(calcofluor white,CFW)染色观察苯乳酸对菌丝顶端生长的破坏作用,利用扫描电子显微镜和透射电子显微镜观察链格孢霉的超微结构变化,通过测定苯乳酸作用前后链格孢霉上清液中N-乙酰葡萄糖胺质量浓度变化研究苯乳酸对菌丝细胞壁的破坏作用,应用荧光双染色法观察苯乳酸对链格孢霉菌丝细胞膜的损伤作用。结果表明,12.5 mmol/L的苯乳酸能有效抑制链格孢霉的生长;与对照组(无菌水处理)相比,苯乳酸处理后链格孢霉顶端生长细胞无明显形变,经12.5 mmol/L苯乳酸处理的链格孢霉上清液中N-乙酰葡萄糖胺质量浓度基本不变;苯乳酸处理24 h,链格孢霉菌丝细胞壁表面无明显损伤,细胞内结构发生明显变化;苯乳酸短时间(4 h)处理链格孢霉,菌丝细胞膜仍较为完整,加入苯乳酸较长时间(8 h)后细胞膜发生破裂。综合分析可知,苯乳酸对链格孢霉的主要作用靶位应不是菌丝体的细胞壁和细胞膜,而是在菌丝体内部,通过破坏菌丝内部细胞器结构或引起细胞内的生化反应,从而抑制链格孢霉的生长和繁殖,发挥抑菌活性。 相似文献
4.
As well-known disturbance rejection methods, active disturbance rejection control and disturbance observer-based control can effectively improve the control performances of complex systems in the presence of disturbances. However, the accurate rejection of multiple disturbances for control systems of practical engineering, for example, the attitude control system of flexible spacecraft, is still a bottleneck problem. In order to further improve the anti-disturbance capability and reduce the conservativeness, this paper proposes a novel enhanced anti-disturbance control law for the attitude control system of flexible spacecraft by combining active disturbance rejection control and disturbance observer-based control in a unified framework. More specifically, the disturbance from flexible vibration is described by an uncertain exogenous system based on the partially known information including elastic damping ratios and modal frequencies. The disturbance observer-based control is utilized to estimate and thereby reject this disturbance. On the other hand, the other disturbances such as external environmental disturbance and complex model nonlinearity are merged into a equivalent disturbance with bounded derivative, which is compensated by using the active disturbance rejection control law. Stability and robustness analysis are carried out for the disturbance observer and extended state observer. Finally, simulation results of low-earth-orbit flexible satellite are presented to verify the effectiveness of proposed methods. 相似文献
5.
《Displays》2021
Medical image segmentation is the most complex and important task in the field of medical image processing and analysis, as it is linked to disease diagnosis accuracy. However, due to the medical image's high complexity and noise, segmentation performance is limited. We propose a novel quadratic polynomial guided fuzzy C-means and dual attention mechanism composite network model architecture to address the aforementioned issues (QPFC-DA). It has mechanisms for channel and spatial edge attention, which guide the content and edge segmentation branches, respectively. The bi-directional long short-term memory network was added after the two content segmentation branches to better integrate multi-scale features and prevent the loss of important features. Furthermore, the fuzzy C-means algorithm guided by the quadratic polynomial can better distinguish the image's weak edge regions and has a degree of noise resistance, resulting in a membership matrix with less ambiguity and a more reliable segmentation result. We also conducted comparison and ablation experiments on three medical data sets. The experimental results show that this method is superior to several other well-known methods. 相似文献
6.
The paper presents a novel blind watermarking scheme for image copyright protection, which is developed in the discrete wavelet transform (DWT) and is based on the singular value decomposition (SVD) and the support vector regression (SVR). Its embedding algorithm hides a watermark bit in the low–low (LL) subband of a target non-overlap block of the host image by modifying a coefficient of U component on SVD version of the block. A blind watermark-extraction is designed using a trained SVR to estimate original coefficients. Subsequently, the watermark bit can be computed using the watermarked coefficient and its corresponding estimate coefficient. Additionally, the particle swarm optimization (PSO) is further utilized to optimize the proposed scheme. Experimental results show the proposed scheme possesses significant improvements in both transparency and robustness, and is superior to existing methods under consideration here. 相似文献
7.
为了获取关于香辛料在哈尔滨风干肠中的应用资料,利用静态顶空进样法从哈尔滨市售两种知名品牌的风干肠香辛料(FX)中收集到挥发性香气成分,连接GC/MC装置进行分析,分别测得FX1中有20种化合物,FX2中有22种化合物,这些化合物均以烯烃类、醇类、醚类、醛类、酮类、酸类、脂类及芳香类有机化学物质为主,而此类化学物质也均属于食品化学中所介绍的香辛料的主要成分的范畴,本实验利用峰面积归一化法通过G170LBA化学工作站数据处理系统得出各化学成分在每个样品中的相对百分比。 相似文献
8.
9.
改进的灰色拓扑预测结合了GM(1,1)模型、拓扑预测与最小二乘法.它通过对一些具有波动性的少量数据进行分析得出比较接近实际的预测值,较大程度上减少了误差.本文通过使用该算法,很好地对高考考生填报志愿时要报考学校的下一年分数进行了预测,验证了它的实际运用价值. 相似文献
10.
针对网上评教中众多不确定性因素使评价结果不科学的实际问题,结合我校实际,构建了网上评教的多级模糊综合评价模型.运用该模型对某教师进行了评价.评价结果与实际情况基本相符,从而为衡量教师的教学水平提供了一种较合理的评价方法. 相似文献