In this paper, we propose a Gauss-Newton algorithm to recover an n-dimensional signal from its phaseless measurements. The algorithm has two stages. In the first stage, the algorithm obtains a good ...initialization by calculating the eigenvector corresponding to the largest eigenvalue of a Hermitian matrix. In the second stage, the algorithm solves an optimization problem iteratively using the Gauss-Newton method. Our initialization method makes full use of all measurements and provides a good initial guess, as long as the number of random measurements is O(n). For real-valued signals, we prove that a resampled version of Gauss-Newton iterations converges to the global optimal solution quadratically with O(n log n) random measurements. Numerical experiments show that the Gauss-Newton method has better empirical performance than other algorithms, such as the Wirtinger flow algorithm and Altmin phase algorithm.
Pyrolysis liquids are the main products in biomass pyrolysis, and the strong acidity limits its utilization. Likewise, activators are required in the process of preparing biomass-based activated ...carbon, and current activators are usually chemical agents and not sustainable. Both issues are addressed with the new concept of using acidic pyrolysis liquids as the activator of biomass-based activated carbon. In the present research, corncob-based activated carbon was prepared with phosphoric acid and pyrolysis liquids (bio-oil and wood vinegar) as activators. The effects of activation temperature and the types of activators on the structure and surface chemical properties of activated carbon were investigated. Results show that the adsorption performance and specific surface area of activated carbon prepared with bio-oil are not as good as that prepared with phosphoric acid and wood vinegar, but its yield is relatively high. Some alkali and earth alkaline metals remain on the activated carbon prepared by bio-oil and wood vinegar. At 450 °C, the surface area and pore volume of activated carbon prepared with bio-oil and wood vinegar were much smaller than the ones prepared with phosphoric acid. Increasing the activation temperature may improve the performance of activated carbon. The specific surface area of activated carbon prepared with wood vinegar as the activator can reach 384.35 m2/g at an activation temperature of 850 °C, which is slightly inferior to that prepared with phosphoric acid as the activator. However, the adsorption amount of methylene blue exceeds the activated carbon prepared with phosphoric acid. This shows that wood vinegar can be used as an activator to prepare biomass-based activated carbon to achieve sustainability of the entire preparation process of biomass-based activated carbon.
Online detection of coal and gangue is the key to intelligent separation of coal and gangue which is significant for improving coal mining efficiency and deducing environmental pollution. To improve ...the detection of coal and gangue under complex conditions, we proposed a cascade network that consists of detector and discriminator. Employing the idea of combining traditional computer vision with deep learning, the multi-channel feature fusion layer was designed in the discriminator. The convolutional neural network (CNN) in the discriminator was optimized from the perspective of loss function and classifier, and a decision function was designed to unify the results of the detector and the discriminator. Finally, we used the visualization to analyze the classification basis during the production by CNN. Our results showed that the cascade network proposed in this study took the characteristics of material truncation as the classification basis, and the detection accuracy reached up to 91.375%.
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•Generalization of CNN is strengthened by combining traditional computer vision.•SVM as classifier improves accuracy of binary classification of coal and gangue.•Cascade improves the performance of coal and gangue detection network.•Difference at truncated surface is the basis of classification coal and gangue.
The orthogonal multi-matching pursuit (OMMP) is a natural extension of the orthogonal matching pursuit (OMP). We denote the OMMP with the parameter M as OMMP(M) where M ≥ 1 is an integer. The main ...difference between OMP and OMMP(M) is that OMMP(M) selects M atoms per iteration, while OMP only adds one atom to the optimal atom set. In this paper, we study the performance of orthogonal multi-matching pursuit under RIP. In particular, we show that, when the measurement matrix A satisfies (25s, 1/10)-RIP, OMMP (M₀) with M₀ = 12 can recover s-sparse signals within s iterations. We furthermore prove that OMMP(M) can recover s-sparse signals within O(s/M) iterations for a large class of M.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The class of Fourier matrices is of special importance in compressed sensing (CS). This paper concerns deterministic construction of CS matrices from Fourier matrices. Using Katz' character sum ...estimation, we are able to design a deterministic procedure to select rows from a Fourier matrix to form a good CS matrix for sparse recovery. The sparsity bound in our construction is similar to that of binary CS matrices constructed by DeVore, which greatly improves previous results for CS matrices from Fourier matrices. Our approach also provides more flexibility in terms of the dimension of CS matrices. This paper also contains a useful improvement to Katz' character sum estimation for quadratic extensions, with an elementary and transparent proof. Based on this improvement, we construct a class of special CS matrices consisting of partial Fourier matrices whose columns are a union of orthonormal bases. As a consequence, our construction yields an approximately mutually unbiased bases from Fourier matrices which is of particular interest to quantum information theory. Some numerical examples are also included.
A novel naphthalimide-based fluorescent probe employing a sulfonamide unit as a thiol-responsive group is reported. It is capable of efficiently distinguishing GSH from cysteine and homocysteine. ...Bioimaging shows that it has high selectivity in living cells and can visualize the level of GSH in lysosomes. It is worth mentioning that different groups on the imide unit can affect the selectivity and reaction dynamics of the probe towards thiols.
The seismic performance index of prefabricated structures is generally obtained via experimental analysis. However, in experimental research, it is impossible that every influencing factor can be ...taken into account. Therefore, the finite element analysis method can be used as a supplementary method for experimental research to carry out parametric analysis of joints. Based on this test, a hysteretic model of steel bars is developed on the ABAQUS platform; meanwhile, the model is used to simulate the seismic analysis of the proposed local reinforced joints. The hysteresis curve obtained via simulation exhibits a high degree of coincidence with the experimental results. Based on the validated model, a detailed parameter analysis of prefabricated local reinforced concrete frame joints is carried out. The analysis results illustrate that the axial pressure ratio at the top of the column has a minimal impact on the joint's performance. Decreasing the stirrup ratio within the core region, enlarging the diameter of the PC steel bar, and increasing the concrete strength that is poured in the keyway and the core region can raise the cumulative energy consumption of the joints, thereby reducing the damage degree of other units and improving the maximum bearing capability of the joints.
While 1q21+ was common genetic alteration and found to have adverse effect on prognosis, the underlying genes remain unclear. Identification of related genes may provide additional help for rational ...intervention. The microarray dataset GSE2658 associated with MM was downloaded from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) were obtained, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed to annotate their functions. The hub genes were derived from the combined results of up-regulated DEGs and weighted gene coexpression network analysis (WGCNA). The receiver operating characteristic (ROC) curves of hub genes were plotted to evaluate correlation with 1q21+. Survival analysis and drug-gene interaction of hub genes were performed separately to find the prognostic value and potential targeted drugs. A total of 55 DEGs were identified. GO and KEGG pathway analyses suggested that the DEGs were related to several pathways of cell proliferation.
were proven to be highly correlated with 1q21+ and have adverse effects on prognosis.
were matched to known interaction-drug. This study revealed potential roles of hub genes in the pathogenesis and progression of MM with 1q21+, further investigations are needed to elucidate the mechanisms.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
As the construction industry is striding towards the industrialization of green buildings, a precast concrete frame beam-column joint with high-strength reinforcement was proposed. Simulate reversed ...cyclic loading was carried out on two precast connections and one cast-in-place connection to examine the seismic behavior of the proposed new precast connection. The main test variables between the two precast connections were the strength of the reinforcement at the bottom of the beam. The failure shape, hysteresis curve, skeleton curve, strength, deformation ability, stiffness degradation, and energy dissipation were monitored and compared with the cast-in-place connection. The findings of this paper showed that the precast joints had good strength reserve, and the seismic performance in the later stage of loading even exceeds the cast-in-place joints. It was also found that the plastic hinge zone of the beam could be moved away from the column surface via reinforcement method. Additionally, based on the experiment, a detailed nonlinear finite element analysis (FEA) method was developed to reproduce the test response of specific types of bending moment-resistant precast concrete beam-column connections under a reversed loading test, which provided a theoretical reference for further research of the connections.
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•Reduced graphene oxide-supported cobalt nanowires nanocomposite is in situ synthesized for the first time.•The nanocomposite has an outstanding performance towards hydrolysis of ...ammonia borane.•The possible mechanism of hydrolysis of ammonia borane is put forward.
Controlled synthesis of magnetic nanocomposite with outstanding catalytic performances is a promising strategy in catalyst industry. We proposed a novel concept for fabrication of reduced graphene oxide-supported cobalt nanowires (RGO/Co-NWs) nanocomposite as high-efficient magnetic catalyst. Unlike the majority of experiments necessitating harsh synthesis conditions such as high-pressure, high-temperature and expensive template, here the RGO/Co-NWs were successfully prepared in aqueous solution under mild conditions with the assistance of external magnetic field. The synthetic process was facile and external magnetic force was adopted to induce the unidirectional self-assembly of cobalt crystals on graphene oxide to form RGO/Co-NWs. The possible formation mechanism laid on the fact that the dipole magnetic moments of the nanoparticles were aligned along the magnetic induction lines with the external magnetic field direction resulting in the formation of nanowires elongating in the direction of the magnetization axis. Simultaneously, a series of controlled reactions were conducted to illuminate the effect of graphene oxide, external magnetic field and PVP on the morphology and size of RGO/Co-NWs in the present approach. More importantly, the nanocomposite exhibited a high catalytic performance towards ammonia borane. Hence the novel nanocomposite holds a great potential for technological applications such as catalyst industry.
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