Probabilistic Results on the Architecture of Mathematical Reasoning Aligned by Cognitive Alternation

We envision a machine capable of solving mathematical problems. Dividing the quantitative reasoning system into two parts: thought processes and cognitive processes, we provide probabilistic descriptions of the architecture

Catalytically Active Boron Nitride in Acetylene Hydrochlorination

This study presents the discovery that porous boron nitride (p-BN) is active in acetylene hydrochlorination, although boron nitride (BN) is generally considered chemically inert. An acetylene conversion of 9996 is achieved with a vinyl chloride selectivity over 9996 at 280 degrees C at a gas hourly space velocity (GHSV) of 1.32 mL min(-1) g(-1). By contrast, the commercially available crystallized hexagonal BN (h-BN) exhibits no catalytic activity. Furthermore, this p-BN is rather durable as demonstrated by a 1000 h lifetime test. Catalytic tests, spectroscopic characterization, and theoretical calculations indicate that the activity likely originates from the defects and edge sites. Particularly, the armchair edges of BN can polarize and activate acetylene, which then reacts with gaseous HCl giving vinyl chloride as the product

Main control factors affecting mechanical oil recovery efficiency in complex blocks identified using the improved k-means algorithm.

The system efficiency of pumping units in the middle and late stages of oil recovery is characterized by several factors, complex data and poor regulation. Further, the main control factors that affect system efficiency in different blocks vary greatly; therefore, it is necessary to obtain the block characteristics to effectively improve system efficiency. The k-means algorithm is simple and efficient, but it assumes that all factors have the same amount of influence on the output value. This cannot reflect the obvious difference in the influence of several factors in the block on the efficiency. Moreover, the algorithm is sensitive to the selection of the initial cluster centre point, so each calculation result that reflects the efficiency characteristics of the block system cannot be unified. To solve the aforementioned problems affecting the k-means algorithm, the correlation coefficient of all the factors was first calculated, followed by extracting the system efficiency of the positive and negative indicators of standardization. Next, the moisture value was calculated to obtain the weight of each factor used as a coefficient to calculate the Euclidean distance. Finally, the initial centre point selection of the k-means algorithm problem was solved by combining the dbscan and weighted k-means algorithm. Taking an oil production block in the Daqing Oilfield as the research object, the k-means and improved algorithm are used to analyse the main control factors influencing mechanical production efficiency. The clustering results of the two algorithms have the characteristics of overlapping blocks, but the improved algorithm's clustering findings are as follows: this block features motor utilization, pump efficiency and daily fluid production, which are positively correlated with system efficiency. Further, low-efficiency wells are characterized by the fact that the pump diameter, power consumption, water content, daily fluid production, oil pressure and casing pressure are significantly lower than the block average; high-efficiency wells are characterized by pump depths lower than the block average. For this block, it is possible to reduce the depth of the lower pump and increase the water-injection effect to increase the output under conditions of meeting the submergence degree, which can effectively improve the system efficiency

Measurement of Cloud Top Height: Comparison of MODIS and Ground-Based Millimeter Radar

Cloud top height (CTH) is an essential pareter for the general circulation model in understanding the impact of clouds on the Earth’s radiation budget and global climate change. This paper compares the CTH products, derived from the Moderate Resolution Imaging Spectroradiometer (MODIS), onboard the Aqua and Terra satellites with ground-based Ka band radar data in Beijing from 2014 to 2017. The aim was to investigate the data accuracy and the difference in CTH measurements between passive satellite data and active ground-based radar data. The results show that MODIS, on average, underestimates CTH relative to radar by −1.08 ± 2.48 km, but with a median difference of −0.65 km and about 48% of differences are within 1 km. Statistically, MODIS CTHs which are greater than 6 km show lower discrepancy to radar CTH than those of MODIS CTHs less than 4 km. The CTH difference is independent of cloud fraction and cloud layer. It shows strong dependence on cloud depth, decreasing as cloud depth increases. There is a tendency for MODIS to underestimate high thin clouds but overestimate low thin clouds relative to radar. Total ozone, SO2, CO, NO2, aerosol PM10, total water vapor and temperature inversion show unobvious influences in the CTH discrepancy. It is shown that the MODIS CO2-slicing technique performs much better than IRW (infrared window) technique when cloud layer is higher than 2 km. The average difference calculated from all comparisons by CO2-slicing technique and IRW technique is 0.09 ± 1.58 km, and −2.20 ± 2.73 km, respectively

Design and Verification of a Double-Grating Spectrometer System (DGSS) for Simultaneous Observation of Aerosols, Water Vapor and Clouds

Simultaneous observation of aerosols, water vapor, and clouds is conducive to the analysis of their interactions, and the consistency of observation equipment, instrument performance, and observation time is crucial. Molecular oxygen A-band (758–778 nm) and water vapor absorption band (758–880 nm) are two bands with similar wavelengths, and the hyperspectral remote sensing information of these two bands can be exploited to invert the vertical profile of aerosol and water vapor. In this paper, a double-grating spectrometer system (DGSS) was developed. DGSS uses a telescope system and fiber to introduce multi-angle, double-band sunlight, and it splits light synchronously (non-sequentially) to different positions of the detector through a slit plate and two gratings. The DGSS was calibrated in the laboratory and observed in the external field. The results indicated that the spectral resolution reached 0.06 nm (molecular oxygen A-band, 758–778 nm) and 0.24 nm (water vapor absorption band, 758–880 nm). Meanwhile, the spectra of the two bands (three angles in each band) are not aliased on the detector. Besides, the multi-angle simultaneous observation of the high-resolution spectra of the two bands is realized, which proves the effectiveness of this method. This study will provide a scientific basis for the observation of aerosol, water vapor, and cloud ground-based networks

theactivityandstabilityofpdcl2cncatalystforacetylenehydrochlorination

Carbon supported PdCl2 is highly active in catalyzing acetylene hydrochlorination reaction, but deactivates rather quickly. Upon nitrogen doping in the carbon structure, the stability of the PdCl2 catalysts is significantly improved. Furthermore, the results show that 900 A degrees C is a preferred doping temperature. The acetylene conversion keeps above 90% even after 1200 min time on stream whereas the one without nitrogen doping drops to below 10% after 450 min. The stabilizing mechanism of nitrogen doping on catalyst was studied

Polymer nanocomposite dielectrics for capacitive energy storage

Owing to their excellent discharged energy density over a broad temperature range, polymer nanocomposites offer immense potential as dielectric materials in advanced electrical and electronic systems, such as intelligent electric vehicles, smart grids and renewable energy generation. In recent years, various nanoscale approaches have been developed to induce appreciable enhancement in discharged energy density. In this Review, we discuss the state-of-the-art polymer nanocomposites with improved energy density from three key aspects: dipole activity, breakdown resistance and heat tolerance. We also describe the physical properties of polymer nanocomposite interfaces, showing how the electrical, mechanical and thermal characteristics impact energy storage performances and how they are interrelated. Further, we discuss multi-level nanotechnologies including monomer design, crosslinking, polymer blending, nanofiller incorporation and multilayer fabrication. We conclude by presenting the current challenges and future opportunities in this field

Mechanical properties evaluation of metacarpophalangeal joint prosthesis with new titanium-nickel memory alloy: a cadaver study

Abstract Objective Ni-Ti memory alloys are unusual materials for hard-tissue replacement because of their unique superelasticity, good biocompatibility, high strength, low specific gravity, low magnetism, wear resistance, corrosion resistance and fatigue resistance. The current study aims to evaluate its mechanical properties and provide biomechanical basis for the clinical application of the prosthesis. Methods Ten adult metacarpophalangeal joint specimens were randomly divided into a prosthesis group (n = 5, underwent metacarpophalangeal joint prosthesis) and a control group (n = 5, underwent sham operation). Firstly, the axial compression strength was tested with BOSE material testing machine to evaluate its biomechanical strength. Secondly, these specimens were tested for strain changes using BOSE material testing machine and GOM non-contact optical strain measurement system to evaluate the stress changes. Thirdly, fatigue test was performed between groups. Lastly, the mechanical wear of the metacarpophalangeal joint prosthesis was tested with ETK5510 material testing machine to study its mechanical properties. Results Axial compression stiffness in the prosthesis group was greater than that in the control group in terms of 30 ° and 60 ° flexion positions (P  0.05). In the fatigue wear test, the mean mass loss in the prosthesis group’s prosthesis was 17.2 mg and 17.619 mm3, respectively. The mean volume wear rate was 0.12%. There was no statistically significant difference in the maximum pull-out force of the metacarpal, phalangeal, and polymer polyethylene pads between the prosthesis group and the control group specimens. Conclusions Ni-Ti memory alloy metacarpophalangeal joint prosthesis conforms to the biomechanical characteristics of metacarpophalangeal joints without implants, and the fatigue strength can fully meet the needs of metacarpophalangeal joint activities after joint replacement