Abstract
Applications of intelligent robot iterative inspection system in substation are attracting extensive interests. The defect detection in inspection system must consider both real-time and ...accuracy on small database samples. This paper proposes a defect detection network based on the attention model. We combine a triplet attention module with Yolo-v5 network for producing richer representations of defect features, which can improve the accuracy in calculating fast situation. We also give a robust data enhancement mechanism for extending the database. The experiment dataset contains actual images gathering from substation and they are labelled as PASCAL VOC dataset format by safety inspectors with many years of experience. The experiment results can demonstrate that the proposed method can effectively improve the accuracy without reducing the real time performance.
A nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) system with a 45 mm variable temperature (VT) sample probe (VT-NMR-MRI) was developed as an innovative technique for in situ ...monitoring of food phase transition. The system was designed to allow for dual deployment in either a freezing (−37 °C) or high temperature (150 °C) environment. The major breakthrough of the developed VT-NMR-MRI system is that it is able to measure the water states simultaneously in situ during food processing. The performance of the VT-NMR-MRI system was evaluated by measuring the phase transition for salmon flesh and hen egg samples. The NMR relaxometry results demonstrated that the freezing point of salmon flesh was −8.08 °C, and the salmon flesh denaturation temperature was 42.16 °C. The protein denaturation of egg was 70.61 °C, and the protein denaturation occurred at 24.12 min. Meanwhile, the use of MRI in phase transition of food was also investigated to gain internal structural information. All these results showed that the VT-NMR-MRI system provided an effective means for in situ monitoring of phase transition in food processing.
The fast-field cycling nuclear magnetic relaxation technique (NMRD) offers opportunities on multiple scales of both time and distance for characterizing the molecular dynamics and transport ...properties of complex liquids in bulk or in confined environments. Therefore, NMRD can characterize fundamental properties such as surface correlation times, diffusion coefficients, and dynamical surface affinity (NMR wettability) for confined liquids in porous materials. This paper presents the applications of NMRD to petroleum tight sandstone rocks for giving new information on pore-size distribution (PSD) and the surface wettability of brine confined within pores. The bimodal PSD in tight sandstones is extended to much smaller pores compared with the quasi monomodal PSD of conventional sandstones that is known to be centered on very large pores of several tens of μm. The interpretation of the NMRD profiles of tight sandstones has shown a water surface diffusion about one-third of the bulk diffusion. We evidenced for the first time a pore-size dependence of the water wettability in tight sandstones that qualifies the FFC–NMRD technique for probing (in a single day experiment) the molecular dynamics and wettability of these important unconventional sandstone reservoir rocks. On the basis of the promising results obtained, we believe that NMRD experiments will be a critical tool for investigating in situ the molecular dynamics and wettability of petroleum unconventional reservoirs.
•Effects of transport vibration on Hami melon softening during storage were studied.•The physiological and biochemical characteristics related to softening were monitored.•MR images, T2 relaxation ...times and water traits of the fruits were measured.•HW in combination with shellac can reduce melon softening caused by vibration.
The effects of transport vibration on Hami melon (Cucumis melo var. saccharinus) softening during storage (room temperature) were studied. Hot water (HW) and HW in combination with shellac coating (HW+shellac) were used to reduce melon softening caused by vibration. Changes in flesh firmness, hydrolase activities, cell wall constituents, cell membrane permeability and weight loss were monitored periodically in stored fruits for 28 days following vibration treatment. Magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) were used to assess the internal morphological characteristics, transverse relaxation times, and water distribution of Hami melons. The results revealed that vibration contributes to Hami melon softening during storage. Compared to HW treatment, HW+shellac was more effective in reducing melon softening by reducing cell wall hydrolase activity, cell membrane leakage, fruit weight loss, and loss of cell wall constituents. The results were confirmed by MRI and NMR.
Two-dimensional (2D) NMR relaxometry has been widely used as a powerful new tool for identifying and characterizing molecular dynamics. Various inversion algorithms have been introduced to obtain the ...versatile relaxation information conveyed by spectra. The inversion procedure is especially challenging because the relevant data are huge in 2D cases and the inversion problem is ill-posed. Here, we propose a new method to process the 2D NMR relaxometry data. Our approach varies from Tikhonov regularization, known previously in CONTIN and Maximum Entropy (MaxEnt) methods, which need additional efforts to compute an appropriate regularization factor. This variety improves Butler–Reeds–Dawson algorithm to optimize the Tikhonov regularization problem and the regularization factor is calculated alongside. The calculation is considerably faster than the mentioned algorithms. The proposed method is compared with some widely used methods on simulated datasets, regarding algorithm efficiency and noise vulnerability. Also, the result of the experimental data is presented to test the practical utility of the proposed algorithm. The results suggest that our approach is efficient and robust. It can meet different application requirements.
In recent years, Zhejiang's exports continued to grow rapidly, becoming the main force of economic development in open economy. However, with the spreading of the U.S. "subprime crisis " and the ...global economic crisis, the global economy fall into recession which inevitably affected the export trade. This paper endeavors to propose some suggestions on enhancing export competitiveness of Zhejiang , based on the actual situation of Zhejiang's exports and the analysis of the factors of the export competitiveness during the economic crisis.
Development of microstructure of early cement paste （0-6 h） was investigated with 1H low- field NMR. It was found that T2 （transverse relaxation time） distributions of fresh cement paste were bimodal ...and two peaks were ＇long component＇ and ＇short component＇. Separation degree of two peaks was a sign of exchange of water within flocculation and outside flocculation. Factors such as water cement ratio, specific surface area and dosage of superplasticizer had influences on the separation degree： the separation degree increased with the water cement ratio; the separation degree of cement paste prepared with cement with a high specific surface area was zero; dosage of superplasticizer will decrease separation degree. Results also suggested that T2 distribution gradually moved to the left and T2 of long component and initial fluidity were linearly correlated.
It is difficult to reflect the properties of samples from the signal directly collected by the low field nuclear magnetic resonance (NMR) analyzer. People must obtain the relationship between the ...relaxation time and the original signal amplitude of every relaxation component by inversion algorithm. Consequently, the technology of T2 spectrum inversion is crucial to the application of NMR data. This study optimized the regularization factor selection method and presented the regularization algorithm for inversion of low field NMR relaxation distribution, which is based on the regularization theory of ill-posed inverse problem. The results of numerical simulation experiments by Matlab7.0 showed that this method could effectively analyze and process the NMR relaxation data.
Development of microstructure of early cement paste (0-6 h) was investigated with super(1)H low-field NMR. It was found that T sub(2) (transverse relaxation time) distributions of fresh cement paste ...were bimodal and two peaks were 'long component' and 'short component'. Separation degree of two peaks was a sign of exchange of water within flocculation and outside flocculation. Factors such as water cement ratio, specific surface area and dosage of superplasticizer had influences on the separation degree: the separation degree increased with the water cement ratio; the separation degree of cement paste prepared with cement with a high specific surface area was zero; dosage of superplasticizer will decrease separation degree. Results also suggested that T sub(2) distribution gradually moved to the left and T sub(2) of long component and initial fluidity were linearly correlated.
Development of microstructure of early cement paste (0–6 h) was investigated with
1
H low-field NMR. It was found that
T
2
(transverse relaxation time) distributions of fresh cement paste were ...bimodal and two peaks were ‘long component’ and ‘short component’. Separation degree of two peaks was a sign of exchange of water within flocculation and outside flocculation. Factors such as water cement ratio, specific surface area and dosage of superplasticizer had influences on the separation degree: the separation degree increased with the water cement ratio; the separation degree of cement paste prepared with cement with a high specific surface area was zero; dosage of superplasticizer will decrease separation degree. Results also suggested that
T
2
distribution gradually moved to the left and
T
2
of long component and initial fluidity were linearly correlated.
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