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The operations of the operators are important for nuclear safety, but conventional operating experience feedback and common data-driven methods make it difficult to explicitly find valuable information hidden in these operational sequences that can help the operator to provide advice at the operational level. During the nuclear power plant (NPP) operation, a large amount of historical operating data is accumulated, which records the operational sequences of the operators and the state parameters of equipment. Therefore, this paper proposes the use of association rule techniques to mine the NPP operating data to discover the operational characteristics of operators and reveal their possible impact on the NPP operation. This work helps to improve the operational performance of operators and prevent human-factor events. To this end, the concept of state switching values for describing the operating states of NPPs is proposed to enable the proposed method to be adapted to different practical application scenarios. A sequence segmentation method is proposed to be able to transform historical NPP operating data into a sequence data set for association rule mining. Furthermore, an ensemble algorithm based on sequence pattern mining and sequence rule mining and its postprocessing method are designed. The empirical study was carried out using 20 batches of historical operating data of the cold start-up. A total of 164 original association rules are generated using the proposed method and were analyzed by experts. The recommendations were made for 4 different cases that would improve the operational performance of the operators. [ABSTRACT FROM AUTHOR]

Nuclear power plant operating data are characterized by a large variety, strong coupling, and low data value density. When using machine learning techniques for fault diagnosis and other related research, feature selection enables dimensionality reduction while maintaining the physical meaning of the original features, thus improving the computational efficiency and generalization ability of the learning model. In this paper, a correlation-based feature selection algorithm is developed to implement feature selection of nuclear power plant operating data. The proposed algorithm is verified by experiments and compared with traditional correlation-based feature selection algorithms. The experiments and comparison results show that the proposed algorithm is effective in realizing the dimensionality reduction of nuclear power plant operating data. [ABSTRACT FROM AUTHOR]

Multipartite secret sharing schemes are those that have multipartite access structures. The set of the participants in those schemes is divided into several parts, and all the participants in the same part play the equivalent role. One type of such access structure is the compartmented access structure, and the other is the hierarchical access structure. We propose an efficient compartmented multisecret sharing scheme based on the linear homogeneous recurrence (LHR) relations. In the construction phase, the shared secrets are hidden in some terms of the linear homogeneous recurrence sequence. In the recovery phase, the shared secrets are obtained by solving those terms in which the shared secrets are hidden. When the global threshold is t , our scheme can reduce the computational complexity of the compartmented secret sharing schemes from the exponential time to polynomial time. The security of the proposed scheme is based on Shamir's threshold scheme, i.e., our scheme is perfect and ideal. Moreover, it is efficient to share the multisecret and to change the shared secrets in the proposed scheme. [ABSTRACT FROM AUTHOR]

Taking different parts of Tan mutton in Ningxia as samples, the rheological properties of Tan mutton at 0, 2, 4, and 8 days were studied by rotational rheometer. The stress relaxation under static state and the dynamic oscillation rheological properties in flow state was examined. The dynamic storage modulus, loss modulus, and complex viscosity with angular frequency were measured. The microstructure of Tan sheep was observed by field emission scanning electron microscope (FESEM) to elucidate the changes of surface microstructure of muscle fibers. The results showed that the Tan mutton was a non‐Newtonian fluid and exhibits pseudoplastic behavior. The apparent viscosity decreased with the increase of shear rate. The longissimus dorsi muscle was stored in 2, 4, 6, and 8 days. The Ostwald‐de Waele model had a coefficient of fit of 0.9245, 0.986, 0.992, 0.986, and the Ostwald‐de Waele model of the hind legmuscles at 2, 4, 6, and 8 days had a coefficient of fit of 0.744, 0.911, 0.346, and 0.604. The model fitting effect of the long muscle was better than that of the hind leg muscle, which indicated that the flow effect of the longissimus dorsi muscle was better than that of the hind leg muscle during processing. Overall, the Ostwald de Waele model could better describe the flow properties of meat emulsions, which was better than the Herschel Bulkley model. Practical applications: In this study, we have demonstrated that rheological property of Tan mutton was changed with the extension of time. This study can provide theoretical guidance for the improvement of meat deep processing technology. [ABSTRACT FROM AUTHOR]

This study was conducted to determine the correlation among serum biochemical indices, slaughter traits, texture characteristics and water-holding capacity in Tan sheep. Eighty Tan sheep aged 4–6 months were selected. Blood samples were collected from live animals to analyse serum biochemical indices. The slaughter traits, texture characteristics and water-holding capacity of meat were assessed after slaughter. There were highly significant correlations (p<.01) and high linear regression R values among serum biochemical indices, slaughter traits, meat texture characteristics and water-holding capacity in Tan sheep. Therefore, this study has demonstrated that the meat qualities of Tan mutton may be evaluated by the serum biochemical indices of live Tan sheep. This study was conducted to determine the correlation among serum biochemical indices, slaughter traits, texture characteristics and water-holding capacity in Tan sheep. This study has demonstrated that meat qualities of Tan mutton may be assessed by the serum biochemical indices of live Tan sheep. It is necessary to determine slaughter traits, meat texture characteristics and water-holding capacity of meat, which are major indicators for assessing meat and meat products by consumers. [ABSTRACT FROM AUTHOR]

The composites of porous Co3O4/MWCNTs and porous Co3O4/Co/RGO have been prepared by the wet chemical method and carbonization process. Due to well impedance matching characteristics, dielectric loss properties and highly porous structure Co3O4/Co/RGO composite displays extremely strong electromagnetic wave absorption with a maximum reflection loss of –54.2 dB at 13.14 GHz and the absorption bandwidth with the reflection loss exceeding –10 dB is 5.46 GHz (10.24–15.7 GHz) with the thickness of only 2.0 mm. Furthermore, the addition amount of the composite into paraffin matrix is merely 10 wt %, less than that of most EMW absorber reported previously. Therefore, Co3O4/Co/RGO composite can be used as a promising lightweight EMW absorbing material. [ABSTRACT FROM AUTHOR]

In this paper, the MOFs-derived carbonaceous ZnO and RGO (carbonaceous ZnO/RGO) composites have been prepared by the wet chemical method and carbonization process. The as-prepared products are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), Raman spectra, thermogravimetric (TG) analysis and X-ray photoelectron spectroscopy (XPS). The electromagnetic parameters of carbonaceous ZnO/RGO composites are investigated by the vector network analyzer. The results exhibit carbonaceous ZnO/RGO composites have a maximum absorption of − 3 7. 1 2 dB at 6 GHz with thickness of 3.5 mm and the effective absorption (below − 1 0 dB) bandwidth is up to 1.92 GHz (from 5.28 to 7.2 GHz). Thus, the carbonaceous ZnO/RGO composites have great potential in the field of electromagnetic wave absorption. A simple wet chemical method has been employed to synthesize MOF and GO composites, and the MOF-derived carbonaceous ZnO and RGO are prepared by simple heat treatments of MOFs precursors and GO under inert gas condition. The carbonaceous ZnO/RGO composites also exhibit enhanced microwave absorption properties. [ABSTRACT FROM AUTHOR]

Composites of porous Co0.5Zn0.5 zeolitic imidazolate framework (CZ-ZIF)-derived binary Co/ZnO with reduced graphene oxide (RGO) have been prepared by a wet chemical method and carbonization process. CZ-ZIF-derived Co/ZnO microframes with diameter of about 250 nm were dispersed onto the surface of RGO nanosheets. The impedance matching of the composite could be adjusted by controlling the weight ratio of RGO to Co/ZnO microframes. Due to its porous structure, excellent impedance matching, and dielectric loss characteristics, the Co/ZnO/RGO composite exhibited maximum reflection loss (RL) of − 52.2 dB at 10.96 GHz. Coatings with thickness of 2.0 mm to 4.0 mm showed bandwidth of 5.6 GHz (from 8.72 GHz to 14.32 GHz) for RL of − 10 dB (90% absorption). Additionally, the amount of composite added into paraffin matrix was only 8 wt.%, less than for most electromagnetic (EM) wave absorbers in previous reports. Therefore, such Co/ZnO/RGO composites may be promising candidate EM wave absorbing materials. [ABSTRACT FROM AUTHOR]

The role of the counter electrode (CE) in dye-sensitized solar cell (DSSC) is to collect electrons from the external circuit and reduce I to I in the electrolyte. In this paper, the perovskite-phase LaSrCoO (LSCO) nanoparticles were synthesized through a sol-gel method and used as the CE for DSSC. The cell showed a power conversion efficiency ( PCE) of 3.24 %. To further improve the PCE of CE of the LSCO nanoparticles, the nanocomposites of the LSCO nanoparticles with reduced graphene oxide (LSCO@RGO) have been prepared via a simply physical mixing method and served as the efficient CE for DSSC. The LSCO@RGO nanocomposites exhibit excellent electrocatalytic performance for reduction of triiodide, owing to the positive synergetic effect between LSCO nanoparticles and RGO sheets. As a consequence, the DSSC with the LSCO@RGO nanocomposites CE yielded a PCE of 6.32 %, which is observably higher than that of using pristine LSCO CE (3.24 %) or RGO CE (4.54 %) alone, and up to 88 % of the Pt CE (7.18 %). [ABSTRACT FROM AUTHOR]

It is well-known that hyponormal operators have many interesting properties, for example, if the restriction $$T|_{{\mathcal {M}}}$$ of the hyponormal operator T on its nontrivial closed invariant subspace $${\mathcal {M}}$$ is normal, then $${\mathcal {M}}$$ reduces T. In order to discuss the reducibility of invariant subspaces of an operator, four properties of invariant subspaces ( $$R_{i}, i=1,\ldots ,4$$ ) are introduced. Among others, it is proved that, for a k-quasi- A( n) operator T, if the restriction $$T|_{{\mathcal {M}}}$$ is normal and injective, then $${\mathcal {M}}$$ reduces T, thus the function $$\sigma :T\longmapsto \sigma (T)$$ is continuous on the class of k-quasiclass- A( n) operators. Some examples related to class A( n) and n-paranormal operator are given which imply that the inclusion relations are strict. [ABSTRACT FROM AUTHOR]

Let n be a positive integer, an operator T belongs to class A( n) if $$|T^{1+n}|^{2/(1+n)} \geq |T|^{2}$$ , which is a generalization of class A and a subclass of n-paranormal operators, i.e., $${\parallel}T^{1+n}x{\parallel}^{1/(1+n)} \geq {\parallel}Tx{\parallel}$$ for unit vector x. It is showed that if T is a class A( n) or n-paranormal operator, then the spectral mapping theorem on Weyl spectrum of T holds. If T belongs to class A( n), then the nonzero points of its point spectrum and joint point spectrum are identical, the nonzero points of its approximate point spectrum and joint approximate point spectrum are identical. [ABSTRACT FROM AUTHOR]

Inspired by the problem of powers of hyponormal operators, this paper is to discuss the structure on powers of p-hyponormal and log-hyponormal operators. The structure on powers of operators consists of same-side structure and different-side structure. The same-side structure means relations between $$T^{{*}^{n+m}} T^{n+m}$$ and $$T^{{*}^{n}} T^n ({\rm or} T^nT^{{*}^{n}}\,{\rm and}\,T^{n+m}T^{{*}^{n+m}})$$ , and the different-side structure means relations between $$T^{{*}^{m}} T^{m}\,{\rm and}\,T^{n}T^{{*}^{n}}$$ where m, n are positive integers and T is a bounded linear operator on a Hilbert space. Thus, the original problem of powers of hyponormal operators belongs to different-side structure on powers of hyponormal operators. The structure on powers of p-hyponormal operators for p > 0 is emphasized. Also, some applications are obtained. [ABSTRACT FROM AUTHOR]